diff --git a/.gitattributes b/.gitattributes
index 8ce9c6b..1bdc91e 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,8 +1,10 @@
 * whitespace=!indent,trail,space
 *.[ch] whitespace=indent,trail,space diff=cpp
 *.sh whitespace=indent,trail,space eol=lf
-*.perl eol=lf
-*.pm eol=lf
+*.perl eol=lf diff=perl
+*.pl eof=lf diff=perl
+*.pm eol=lf diff=perl
+*.py eol=lf diff=python
 /Documentation/git-*.txt eol=lf
 /command-list.txt eol=lf
 /GIT-VERSION-GEN eol=lf
diff --git a/.gitignore b/.gitignore
index 833ef3b..388cc4b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@
 /GIT-LDFLAGS
 /GIT-PREFIX
 /GIT-PERL-DEFINES
+/GIT-PERL-HEADER
 /GIT-PYTHON-VARS
 /GIT-SCRIPT-DEFINES
 /GIT-USER-AGENT
@@ -34,6 +35,7 @@
 /git-clone
 /git-column
 /git-commit
+/git-commit-graph
 /git-commit-tree
 /git-config
 /git-count-objects
@@ -140,6 +142,7 @@
 /git-rm
 /git-send-email
 /git-send-pack
+/git-serve
 /git-sh-i18n
 /git-sh-i18n--envsubst
 /git-sh-setup
@@ -179,7 +182,7 @@
 /gitweb/gitweb.cgi
 /gitweb/static/gitweb.js
 /gitweb/static/gitweb.min.*
-/common-cmds.h
+/command-list.h
 *.tar.gz
 *.dsc
 *.deb
diff --git a/.mailmap b/.mailmap
index 7c71e88..df7cf63 100644
--- a/.mailmap
+++ b/.mailmap
@@ -25,8 +25,8 @@
 Benoit Sigoure <tsunanet@gmail.com> <tsuna@lrde.epita.fr>
 Bernt Hansen <bernt@norang.ca> <bernt@alumni.uwaterloo.ca>
 Brandon Casey <drafnel@gmail.com> <casey@nrlssc.navy.mil>
-brian m. carlson <sandals@crustytoothpaste.ath.cx> Brian M. Carlson <sandals@crustytoothpaste.ath.cx>
-brian m. carlson <sandals@crustytoothpaste.ath.cx> <sandals@crustytoothpaste.net>
+brian m. carlson <sandals@crustytoothpaste.net> Brian M. Carlson <sandals@crustytoothpaste.ath.cx>
+brian m. carlson <sandals@crustytoothpaste.net> <sandals@crustytoothpaste.ath.cx>
 Bryan Larsen <bryan@larsen.st> <bryan.larsen@gmail.com>
 Bryan Larsen <bryan@larsen.st> <bryanlarsen@yahoo.com>
 Cheng Renquan <crquan@gmail.com>
diff --git a/.travis.yml b/.travis.yml
index 5f5ee4f..4d4e26c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,10 +16,13 @@
 
 addons:
   apt:
+    sources:
+    - ubuntu-toolchain-r-test
     packages:
     - language-pack-is
     - git-svn
     - apache2
+    - gcc-8
 
 matrix:
   include:
diff --git a/Documentation/Makefile b/Documentation/Makefile
index 6232143..d079d7c 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -78,6 +78,7 @@
 TECH_DOCS += technical/pack-protocol
 TECH_DOCS += technical/protocol-capabilities
 TECH_DOCS += technical/protocol-common
+TECH_DOCS += technical/protocol-v2
 TECH_DOCS += technical/racy-git
 TECH_DOCS += technical/send-pack-pipeline
 TECH_DOCS += technical/shallow
@@ -184,7 +185,7 @@
 ASCIIDOC_CONF =
 ASCIIDOC_HTML = xhtml5
 ASCIIDOC_DOCBOOK = docbook45
-ASCIIDOC_EXTRA += -acompat-mode
+ASCIIDOC_EXTRA += -acompat-mode -atabsize=8
 ASCIIDOC_EXTRA += -I. -rasciidoctor-extensions
 ASCIIDOC_EXTRA += -alitdd='&\#x2d;&\#x2d;'
 DBLATEX_COMMON =
diff --git a/Documentation/RelNotes/2.13.7.txt b/Documentation/RelNotes/2.13.7.txt
new file mode 100644
index 0000000..09fc014
--- /dev/null
+++ b/Documentation/RelNotes/2.13.7.txt
@@ -0,0 +1,20 @@
+Git v2.13.7 Release Notes
+=========================
+
+Fixes since v2.13.6
+-------------------
+
+ * Submodule "names" come from the untrusted .gitmodules file, but we
+   blindly append them to $GIT_DIR/modules to create our on-disk repo
+   paths. This means you can do bad things by putting "../" into the
+   name. We now enforce some rules for submodule names which will cause
+   Git to ignore these malicious names (CVE-2018-11235).
+
+   Credit for finding this vulnerability and the proof of concept from
+   which the test script was adapted goes to Etienne Stalmans.
+
+ * It was possible to trick the code that sanity-checks paths on NTFS
+   into reading random piece of memory (CVE-2018-11233).
+
+Credit for fixing for these bugs goes to Jeff King, Johannes
+Schindelin and others.
diff --git a/Documentation/RelNotes/2.14.4.txt b/Documentation/RelNotes/2.14.4.txt
new file mode 100644
index 0000000..97755a8
--- /dev/null
+++ b/Documentation/RelNotes/2.14.4.txt
@@ -0,0 +1,5 @@
+Git v2.14.4 Release Notes
+=========================
+
+This release is to forward-port the fixes made in the v2.13.7 version
+of Git.  See its release notes for details.
diff --git a/Documentation/RelNotes/2.15.2.txt b/Documentation/RelNotes/2.15.2.txt
index 9f7e28f..b480e56 100644
--- a/Documentation/RelNotes/2.15.2.txt
+++ b/Documentation/RelNotes/2.15.2.txt
@@ -43,5 +43,8 @@
  * Clarify and enhance documentation for "merge-base --fork-point", as
    it was clear what it computed but not why/what for.
 
+ * This release also contains the fixes made in the v2.13.7 version of
+   Git.  See its release notes for details.
+
 
 Also contains various documentation updates and code clean-ups.
diff --git a/Documentation/RelNotes/2.16.4.txt b/Documentation/RelNotes/2.16.4.txt
new file mode 100644
index 0000000..6be538b
--- /dev/null
+++ b/Documentation/RelNotes/2.16.4.txt
@@ -0,0 +1,5 @@
+Git v2.16.4 Release Notes
+=========================
+
+This release is to forward-port the fixes made in the v2.13.7 version
+of Git.  See its release notes for details.
diff --git a/Documentation/RelNotes/2.17.1.txt b/Documentation/RelNotes/2.17.1.txt
new file mode 100644
index 0000000..e01384f
--- /dev/null
+++ b/Documentation/RelNotes/2.17.1.txt
@@ -0,0 +1,16 @@
+Git v2.17.1 Release Notes
+=========================
+
+Fixes since v2.17
+-----------------
+
+ * This release contains the same fixes made in the v2.13.7 version of
+   Git, covering CVE-2018-11233 and 11235, and forward-ported to
+   v2.14.4, v2.15.2 and v2.16.4 releases.  See release notes to
+   v2.13.7 for details.
+
+ * In addition to the above fixes, this release has support on the
+   server side to reject pushes to repositories that attempt to create
+   such problematic .gitmodules file etc. as tracked contents, to help
+   hosting sites protect their customers by preventing malicious
+   contents from spreading.
diff --git a/Documentation/RelNotes/2.18.0.txt b/Documentation/RelNotes/2.18.0.txt
index 31c3f6d..326ee9e 100644
--- a/Documentation/RelNotes/2.18.0.txt
+++ b/Documentation/RelNotes/2.18.0.txt
@@ -12,7 +12,9 @@
    want to move to z/d by taking the hint that the entire directory
    'x' moved to 'z'.  A bug causing dirty files involved in a rename
    to be overwritten during merge has also been fixed as part of this
-   work.
+   work.  Incidentally, this also avoids updating a file in the
+   working tree after a (non-trivial) merge whose result matches what
+   our side originally had.
 
  * "git filter-branch" learned to use a different exit code to allow
    the callers to tell the case where there was no new commits to
@@ -44,6 +46,107 @@
 
  * "git mergetools" learned talking to guiffy.
 
+ * The scripts in contrib/emacs/ have outlived their usefulness and
+   have been replaced with a stub that errors out and tells the user
+   there are replacements.
+
+ * The new "checkout-encoding" attribute can ask Git to convert the
+   contents to the specified encoding when checking out to the working
+   tree (and the other way around when checking in).
+
+ * The "git config" command uses separate options e.g. "--int",
+   "--bool", etc. to specify what type the caller wants the value to
+   be interpreted as.  A new "--type=<typename>" option has been
+   introduced, which would make it cleaner to define new types.
+
+ * "git config --get" learned the "--default" option, to help the
+   calling script.  Building on top of the above changes, the
+   "git config" learns "--type=color" type.  Taken together, you can
+   do things like "git config --get foo.color --default blue" and get
+   the ANSI color sequence for the color given to foo.color variable,
+   or "blue" if the variable does not exist.
+
+ * "git ls-remote" learned an option to allow sorting its output based
+   on the refnames being shown.
+
+ * The command line completion (in contrib/) has been taught that "git
+   stash save" has been deprecated ("git stash push" is the preferred
+   spelling in the new world) and does not offer it as a possible
+   completion candidate when "git stash push" can be.
+
+ * "git gc --prune=nonsense" spent long time repacking and then
+   silently failed when underlying "git prune --expire=nonsense"
+   failed to parse its command line.  This has been corrected.
+
+ * Error messages from "git push" can be painted for more visibility.
+
+ * "git http-fetch" (deprecated) had an optional and experimental
+   "feature" to fetch only commits and/or trees, which nobody used.
+   This has been removed.
+
+ * The functionality of "$GIT_DIR/info/grafts" has been superseded by
+   the "refs/replace/" mechanism for some time now, but the internal
+   code had support for it in many places, which has been cleaned up
+   in order to drop support of the "grafts" mechanism.
+
+ * "git worktree add" learned to check out an existing branch.
+
+ * "git --no-pager cmd" did not have short-and-sweet single letter
+   option. Now it does as "-P".
+   (merge 7213c28818 js/no-pager-shorthand later to maint).
+
+ * "git rebase" learned "--rebase-merges" to transplant the whole
+   topology of commit graph elsewhere.
+
+ * "git status" learned to pay attention to UI related diff
+   configuration variables such as diff.renames.
+
+ * The command line completion mechanism (in contrib/) learned to load
+   custom completion file for "git $command" where $command is a
+   custom "git-$command" that the end user has on the $PATH when using
+   newer version of bash.
+
+ * "git send-email" can sometimes offer confirmation dialog "Send this
+   email?" with choices 'Yes', 'No', 'Quit', and 'All'.  A new action
+   'Edit' has been added to this dialog's choice.
+
+ * With merge.renames configuration set to false, the recursive merge
+   strategy can be told not to spend cycles trying to find renamed
+   paths and merge them accordingly.
+
+ * "git status" learned to honor a new status.renames configuration to
+   skip rename detection, which could be useful for those who want to
+   do so without disabling the default rename detection done by the
+   "git diff" command.
+
+ * Command line completion (in contrib/) learned to complete pathnames
+   for various commands better.
+
+ * "git blame" learns to unhighlight uninteresting metadata from the
+   originating commit on lines that are the same as the previous one,
+   and also paint lines in different colors depending on the age of
+   the commit.
+
+ * Transfer protocol v2 learned to support the partial clone.
+
+ * When a short hexadecimal string is used to name an object but there
+   are multiple objects that share the string as the prefix of their
+   names, the code lists these ambiguous candidates in a help message.
+   These object names are now sorted according to their types for
+   easier eyeballing.
+
+ * "git fetch $there $refspec" that talks over protocol v2 can take
+   advantage of server-side ref filtering; the code has been extended
+   so that this mechanism triggers also when fetching with configured
+   refspec.
+
+ * Our HTTP client code used to advertise that we accept gzip encoding
+   from the other side; instead, just let cURL library to advertise
+   and negotiate the best one.
+
+ * "git p4" learned to "unshelve" shelved commit from P4.
+   (merge 123f631761 ld/p4-unshelve later to maint).
+
 
 Performance, Internal Implementation, Development Support etc.
 
@@ -118,6 +221,88 @@
    fast-import.c, which in turn has become the first user of the
    mem-pool API.
 
+ * A build-time option has been added to allow Git to be told to refer
+   to its associated files relative to the main binary, in the same
+   way that has been possible on Windows for quite some time, for
+   Linux, BSDs and Darwin.
+
+ * Precompute and store information necessary for ancestry traversal
+   in a separate file to optimize graph walking.
+
+ * The effort to pass the repository in-core structure throughout the
+   API continues.  This round deals with the code that implements the
+   refs/replace/ mechanism.
+
+ * The build procedure "make DEVELOPER=YesPlease" learned to enable a
+   bit more warning options depending on the compiler used to help
+   developers more.  There also is "make DEVOPTS=tokens" knob
+   available now, for those who want to help fixing warnings we
+   usually ignore, for example.
+
+ * A new version of the transport protocol is being worked on.
+
+ * The code to interface to GPG has been restructured somewhat to make
+   it cleaner to integrate with other types of signature systems later.
+
+ * The code has been taught to use the duplicated information stored
+   in the commit-graph file to learn the tree object name for a commit
+   to avoid opening and parsing the commit object when it makes sense
+   to do so.
+
+ * "git gc" in a large repository takes a lot of time as it considers
+   to repack all objects into one pack by default.  The command has
+   been taught to pretend as if the largest existing packfile is
+   marked with ".keep" so that it is left untouched while objects in
+   other packs and loose ones are repacked.
+
+ * The transport protocol v2 is getting updated further.
+
+ * The codepath around object-info API has been taught to take the
+   repository object (which in turn tells the API which object store
+   the objects are to be located).
+
+ * "git pack-objects" needs to allocate tons of "struct object_entry"
+   while doing its work, and shrinking its size helps the performance
+   quite a bit.
+
+ * The implementation of "git rebase -i --root" has been updated to use
+   the sequencer machinery more.
+
+ * Developer support update, by using BUG() macro instead of die() to
+   mark codepaths that should not happen more clearly.
+
+ * Developer support.  Use newer GCC on one of the builds done at
+   TravisCI.org to get more warnings and errors diagnosed.
+
+ * Conversion from uchar[20] to struct object_id continues.
+
+ * By code restructuring of submodule merge in merge-recursive,
+   informational messages from the codepath are now given using the
+   same mechanism as other output, and honor the merge.verbosity
+   configuration.  The code also learned to give a few new messages
+   when a submodule three-way merge resolves cleanly when one side
+   records a descendant of the commit chosen by the other side.
+
+ * Avoid unchecked snprintf() to make future code auditing easier.
+   (merge ac4896f007 jk/snprintf-truncation later to maint).
+
+ * Many tests hardcode the raw object names, which would change once
+   we migrate away from SHA-1.  While some of them must test against
+   exact object names, most of them do not have to use hardcoded
+   constants in the test.  The latter kind of tests have been updated
+   to test the moral equivalent of the original without hardcoding the
+   actual object names.
+
+ * The list of commands with their various attributes were spread
+   across a few places in the build procedure, but it now is getting a
+   bit more consolidated to allow more automation.
+
+ * Quite a many tests assumed that newly created refs are made as
+   loose refs using the files backend, which have been updated to use
+   proper plumbing like rev-parse and update-ref, to avoid breakage
+   once we start using different ref backends.
+
+
 Also contains various documentation updates and code clean-ups.
 
 
@@ -183,6 +368,146 @@
    attacker's control) buffer overflow.
    (merge d8579accfa bp/fsmonitor-bufsize-fix later to maint).
 
+ * Recent simplification of build procedure forgot a bit of tweak to
+   the build procedure of contrib/mw-to-git/
+   (merge d8698987f3 ab/simplify-perl-makefile later to maint).
+
+ * Moving a submodule that itself has submodule in it with "git mv"
+   forgot to make necessary adjustment to the nested sub-submodules;
+   now the codepath learned to recurse into the submodules.
+
+ * "git config --unset a.b", when "a.b" is the last variable in an
+   otherwise empty section "a", left an empty section "a" behind, and
+   worse yet, a subsequent "git config a.c value" did not reuse that
+   empty shell and instead created a new one.  These have been
+   (partially) corrected.
+   (merge c71d8bb38a js/empty-config-section-fix later to maint).
+
+ * "git worktree remove" learned that "-f" is a shorthand for
+   "--force" option, just like for "git worktree add".
+   (merge d228eea514 sb/worktree-remove-opt-force later to maint).
+
+ * The completion script (in contrib/) learned to clear cached list of
+   command line options upon dot-sourcing it again in a more efficient
+   way.
+   (merge 94408dc71c sg/completion-clear-cached later to maint).
+
+ * "git svn" had a minor thinko/typo which has been fixed.
+   (merge 51db271587 ab/git-svn-get-record-typofix later to maint).
+
+ * During a "rebase -i" session, the code could give older timestamp
+   to commits created by later "pick" than an earlier "reword", which
+   has been corrected.
+   (merge 12f7babd6b js/ident-date-fix later to maint).
+
+ * "git submodule status" did not check the symbolic revision name it
+   computed for the submodule HEAD is not the NULL, and threw it at
+   printf routines, which has been corrected.
+   (merge 0b5e2ea7cf nd/submodule-status-fix later to maint).
+
+ * When fed input that already has In-Reply-To: and/or References:
+   headers and told to add the same information, "git send-email"
+   added these headers separately, instead of appending to an existing
+   one, which is a violation of the RFC.  This has been corrected.
+   (merge 256be1d3f0 sa/send-email-dedup-some-headers later to maint).
+
+ * "git fast-export" had a regression in v2.15.0 era where it skipped
+   some merge commits in certain cases, which has been corrected.
+   (merge be011bbe00 ma/fast-export-skip-merge-fix later to maint).
+
+ * The code did not propagate the terminal width to subprocesses via
+   COLUMNS environment variable, which it now does.  This caused
+   trouble to "git column" helper subprocess when "git tag --column=row"
+   tried to list the existing tags on a display with non-default width.
+   (merge b5d5a567fb nd/term-columns later to maint).
+
+ * We learned that our source files with ".pl" and ".py" extensions
+   are Perl and Python files respectively and changes to them are
+   better viewed as such with appropriate diff drivers.
+   (merge 7818b619e2 ab/perl-python-attrs later to maint).
+
+ * "git rebase -i" sometimes left intermediate "# This is a
+   combination of N commits" message meant for the human consumption
+   inside an editor in the final result in certain corner cases, which
+   has been fixed.
+   (merge 15ef69314d js/rebase-i-clean-msg-after-fixup-continue later to maint).
+
+ * A test to see if the filesystem normalizes UTF-8 filename has been
+   updated to check what we need to know in a more direct way, i.e. a
+   path created in NFC form can be accessed with NFD form (or vice
+   versa) to cope with APFS as well as HFS.
+   (merge 742ae10e35 tb/test-apfs-utf8-normalization later to maint).
+
+ * "git format-patch --cover --attach" created a broken MIME multipart
+   message for the cover letter, which has been fixed by keeping the
+   cover letter as plain text file.
+   (merge 50cd54ef4e bc/format-patch-cover-no-attach later to maint).
+
+ * The split-index feature had a long-standing and dormant bug in
+   certain use of the in-core merge machinery, which has been fixed.
+   (merge 7db118303a en/unpack-trees-split-index-fix later to maint).
+
+ * Asciidoctor gives a reasonable imitation for AsciiDoc, but does not
+   render illustration in a literal block correctly when indented with
+   HT by default. The problem is fixed by forcing 8-space tabs.
+   (merge 379805051d bc/asciidoctor-tab-width later to maint).
+
+ * Code clean-up to adjust to a more recent lockfile API convention that
+   allows lockfile instances kept on the stack.
+   (merge 0fa5a2ed8d ma/lockfile-cleanup later to maint).
+
+ * the_repository->index is not a allocated piece of memory but
+   repo_clear() indiscriminately attempted to free(3) it, which has
+   been corrected.
+   (merge 74373b5f10 nd/repo-clear-keep-the-index later to maint).
+
+ * Code clean-up to avoid non-standard-conformant pointer arithmetic.
+   (merge c112084af9 rs/no-null-ptr-arith-in-fast-export later to maint).
+
+ * Code clean-up to turn history traversal more robust in a
+   semi-corrupt repository.
+   (merge 8702b30fd7 jk/unavailable-can-be-missing later to maint).
+
+ * "git update-ref A B" is supposed to ensure that ref A does not yet
+   exist when B is a NULL OID, but this check was not done correctly
+   for pseudo-refs outside refs/ hierarchy, e.g. MERGE_HEAD.
+
+ * "git submodule update" and "git submodule add" supported the
+   "--reference" option to borrow objects from a neighbouring local
+   repository like "git clone" does, but lacked the more recent
+   invention "--dissociate".  Also "git submodule add" has been taught
+   to take the "--progress" option.
+   (merge a0ef29341a cf/submodule-progress-dissociate later to maint).
+
+ * Update credential-netrc helper (in contrib/) to allow customizing
+   the GPG used to decrypt the encrypted .netrc file.
+   (merge 786ef50a23 lm/credential-netrc later to maint).
+
+ * "git submodule update" attempts two different kinds of "git fetch"
+   against the upstream repository to grab a commit bound at the
+   submodule's path, but it incorrectly gave up if the first kind
+   (i.e. a normal fetch) failed, making the second "last resort" one
+   (i.e. fetching an exact commit object by object name) ineffective.
+   This has been corrected.
+   (merge e30d833671 sb/submodule-update-try-harder later to maint).
+
+ * Error behaviour of "git grep" when it cannot read the index was
+   inconsistent with other commands that uses the index, which has
+   been corrected to error out early.
+   (merge b2aa84c789 sb/grep-die-on-unreadable-index later to maint).
+
+ * We used to call regfree() after regcomp() failed in some codepaths,
+   which have been corrected.
+   (merge 17154b1576 ma/regex-no-regfree-after-comp-fail later to maint).
+
+ * The import-tars script (in contrib/) has been taught to handle
+   tarballs with overly long paths that use PAX extended headers.
+   (merge 12ecea46e3 pa/import-tars-long-names later to maint).
+
+ * "git rev-parse Y..." etc. misbehaved when given endpoints were
+   not committishes.
+   (merge 0ed556d38f en/rev-parse-invalid-range later to maint).
+
  * Other minor doc, test and build updates and code cleanups.
    (merge 248f66ed8e nd/trace-with-env later to maint).
    (merge 14ced5562c ys/bisect-object-id-missing-conversion-fix later to maint).
@@ -198,3 +523,21 @@
    (merge decf711fc1 ps/test-chmtime-get later to maint).
    (merge 22d11a6e8e es/worktree-docs later to maint).
    (merge 92a5dbbc22 tg/use-git-contacts later to maint).
+   (merge adc887221f tq/t1510 later to maint).
+   (merge bed21a8ad6 sg/doc-gc-quote-mismatch-fix later to maint).
+   (merge 73364e4f10 tz/doc-git-urls-reference later to maint).
+   (merge cd1e606bad bc/mailmap-self later to maint).
+   (merge f7997e3682 ao/config-api-doc later to maint).
+   (merge ee930754d8 jk/apply-p-doc later to maint).
+   (merge 011b648646 nd/pack-format-doc later to maint).
+   (merge 87a6bb701a sg/t5310-jgit-bitmap-test later to maint).
+   (merge f6b82970aa sg/t5516-fixes later to maint).
+   (merge 4362da078e sg/t7005-spaces-in-filenames-cleanup later to maint).
+   (merge 7d0ee47c11 js/test-unset-prereq later to maint).
+   (merge 5356a3c354 ah/misc-doc-updates later to maint).
+   (merge 92c4a7a129 nd/completion-aliasfiletype-typofix later to maint).
+   (merge 58bd77b66a nd/pack-unreachable-objects-doc later to maint).
+   (merge 4ed79d5203 sg/t6500-no-redirect-of-stdin later to maint).
+   (merge 17b8a2d6cd jk/config-blob-sans-repo later to maint).
+   (merge 590551ca2c rd/tag-doc-lightweight later to maint).
+   (merge 44f560fc16 rd/init-typo later to maint).
diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches
index 945f8ed..2488544 100644
--- a/Documentation/SubmittingPatches
+++ b/Documentation/SubmittingPatches
@@ -176,6 +176,12 @@
 [[send-patches]]
 === Sending your patches.
 
+:security-ml: footnoteref:[security-ml,The Git Security mailing list: git-security@googlegroups.com]
+
+Before sending any patches, please note that patches that may be
+security relevant should be submitted privately to the Git Security
+mailing list{security-ml}, instead of the public mailing list.
+
 Learn to use format-patch and send-email if possible.  These commands
 are optimized for the workflow of sending patches, avoiding many ways
 your existing e-mail client that is optimized for "multipart/*" mime
@@ -259,17 +265,24 @@
 that starts with `-----BEGIN PGP SIGNED MESSAGE-----`.  That is
 not a text/plain, it's something else.
 
+:security-ml-ref: footnoteref:[security-ml]
+
+As mentioned at the beginning of the section, patches that may be
+security relevant should not be submitted to the public mailing list
+mentioned below, but should instead be sent privately to the Git
+Security mailing list{security-ml-ref}.
+
 Send your patch with "To:" set to the mailing list, with "cc:" listing
 people who are involved in the area you are touching (the `git
 contacts` command in `contrib/contacts/` can help to
 identify them), to solicit comments and reviews.
 
-:1: footnote:[The current maintainer: gitster@pobox.com]
-:2: footnote:[The mailing list: git@vger.kernel.org]
+:current-maintainer: footnote:[The current maintainer: gitster@pobox.com]
+:git-ml: footnote:[The mailing list: git@vger.kernel.org]
 
 After the list reached a consensus that it is a good idea to apply the
-patch, re-send it with "To:" set to the maintainer{1} and "cc:" the
-list{2} for inclusion.
+patch, re-send it with "To:" set to the maintainer{current-maintainer} and "cc:" the
+list{git-ml} for inclusion.
 
 Do not forget to add trailers such as `Acked-by:`, `Reviewed-by:` and
 `Tested-by:` lines as necessary to credit people who helped your
diff --git a/Documentation/config.txt b/Documentation/config.txt
index d6bcb5d..ab641bf 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -530,6 +530,12 @@
 	This variable can be set to 'input',
 	in which case no output conversion is performed.
 
+core.checkRoundtripEncoding::
+	A comma and/or whitespace separated list of encodings that Git
+	performs UTF-8 round trip checks on if they are used in an
+	`working-tree-encoding` attribute (see linkgit:gitattributes[5]).
+	The default value is `SHIFT-JIS`.
+
 core.symlinks::
 	If false, symbolic links are checked out as small plain files that
 	contain the link text. linkgit:git-update-index[1] and
@@ -898,6 +904,10 @@
 This setting defaults to "refs/notes/commits", and it can be overridden by
 the `GIT_NOTES_REF` environment variable.  See linkgit:git-notes[1].
 
+core.commitGraph::
+	Enable git commit graph feature. Allows reading from the
+	commit-graph file.
+
 core.sparseCheckout::
 	Enable "sparse checkout" feature. See section "Sparse checkout" in
 	linkgit:git-read-tree[1] for more information.
@@ -1092,6 +1102,16 @@
 	A boolean to make git-clean do nothing unless given -f,
 	-i or -n.   Defaults to true.
 
+color.advice::
+	A boolean to enable/disable color in hints (e.g. when a push
+	failed, see `advice.*` for a list).  May be set to `always`,
+	`false` (or `never`) or `auto` (or `true`), in which case colors
+	are used only when the error output goes to a terminal. If
+	unset, then the value of `color.ui` is used (`auto` by default).
+
+color.advice.hint::
+	Use customized color for hints.
+
 color.branch::
 	A boolean to enable/disable color in the output of
 	linkgit:git-branch[1]. May be set to `always`,
@@ -1194,6 +1214,15 @@
 	A boolean to enable/disable colored output when the pager is in
 	use (default is true).
 
+color.push::
+	A boolean to enable/disable color in push errors. May be set to
+	`always`, `false` (or `never`) or `auto` (or `true`), in which
+	case colors are used only when the error output goes to a terminal.
+	If unset, then the value of `color.ui` is used (`auto` by default).
+
+color.push.error::
+	Use customized color for push errors.
+
 color.showBranch::
 	A boolean to enable/disable color in the output of
 	linkgit:git-show-branch[1]. May be set to `always`,
@@ -1222,6 +1251,42 @@
 	status short-format), or
 	`unmerged` (files which have unmerged changes).
 
+color.blame.repeatedLines::
+	Use the customized color for the part of git-blame output that
+	is repeated meta information per line (such as commit id,
+	author name, date and timezone). Defaults to cyan.
+
+color.blame.highlightRecent::
+	This can be used to color the metadata of a blame line depending
+	on age of the line.
++
+This setting should be set to a comma-separated list of color and date settings,
+starting and ending with a color, the dates should be set from oldest to newest.
+The metadata will be colored given the colors if the the line was introduced
+before the given timestamp, overwriting older timestamped colors.
++
+Instead of an absolute timestamp relative timestamps work as well, e.g.
+2.weeks.ago is valid to address anything older than 2 weeks.
++
+It defaults to 'blue,12 month ago,white,1 month ago,red', which colors
+everything older than one year blue, recent changes between one month and
+one year old are kept white, and lines introduced within the last month are
+colored red.
+
+blame.coloring::
+	This determines the coloring scheme to be applied to blame
+	output. It can be 'repeatedLines', 'highlightRecent',
+	or 'none' which is the default.
+
+color.transport::
+	A boolean to enable/disable color when pushes are rejected. May be
+	set to `always`, `false` (or `never`) or `auto` (or `true`), in which
+	case colors are used only when the error output goes to a terminal.
+	If unset, then the value of `color.ui` is used (`auto` by default).
+
+color.transport.rejected::
+	Use customized color when a push was rejected.
+
 color.ui::
 	This variable determines the default value for variables such
 	as `color.diff` and `color.grep` that control the use of color
@@ -1347,6 +1412,14 @@
 credentialCache.ignoreSIGHUP::
 	Tell git-credential-cache--daemon to ignore SIGHUP, instead of quitting.
 
+completion.commands::
+	This is only used by git-completion.bash to add or remove
+	commands from the list of completed commands. Normally only
+	porcelain commands and a few select others are completed. You
+	can add more commands, separated by space, in this
+	variable. Prefixing the command with '-' will remove it from
+	the existing list.
+
 include::diff-config.txt[]
 
 difftool.<tool>.path::
@@ -1562,6 +1635,18 @@
 	Make `git gc --auto` return immediately and run in background
 	if the system supports it. Default is true.
 
+gc.bigPackThreshold::
+	If non-zero, all packs larger than this limit are kept when
+	`git gc` is run. This is very similar to `--keep-base-pack`
+	except that all packs that meet the threshold are kept, not
+	just the base pack. Defaults to zero. Common unit suffixes of
+	'k', 'm', or 'g' are supported.
++
+Note that if the number of kept packs is more than gc.autoPackLimit,
+this configuration variable is ignored, all packs except the base pack
+will be repacked. After this the number of packs should go below
+gc.autoPackLimit and gc.bigPackThreshold should be respected again.
+
 gc.logExpiry::
 	If the file gc.log exists, then `git gc --auto` won't run
 	unless that file is more than 'gc.logExpiry' old.  Default is
@@ -2426,6 +2511,7 @@
 pack.depth::
 	The maximum delta depth used by linkgit:git-pack-objects[1] when no
 	maximum depth is given on the command line. Defaults to 50.
+	Maximum value is 4095.
 
 pack.windowMemory::
 	The maximum size of memory that is consumed by each thread
@@ -2462,7 +2548,8 @@
 	The maximum size of a delta, that is cached in
 	linkgit:git-pack-objects[1]. This cache is used to speed up the
 	writing object phase by not having to recompute the final delta
-	result once the best match for all objects is found. Defaults to 1000.
+	result once the best match for all objects is found.
+	Defaults to 1000. Maximum value is 65535.
 
 pack.threads::
 	Specifies the number of threads to spawn when searching for best
@@ -3127,6 +3214,18 @@
 	behavior of linkgit:git-status[1] in Git 1.8.4 and previous.
 	Defaults to false.
 
+status.renameLimit::
+	The number of files to consider when performing rename detection
+	in linkgit:git-status[1] and linkgit:git-commit[1]. Defaults to
+	the value of diff.renameLimit.
+
+status.renames::
+	Whether and how Git detects renames in linkgit:git-status[1] and
+	linkgit:git-commit[1] .  If set to "false", rename detection is
+	disabled. If set to "true", basic rename detection is enabled.
+	If set to "copies" or "copy", Git will detect copies, as well.
+	Defaults to the value of diff.renames.
+
 status.showStash::
 	If set to true, linkgit:git-status[1] will display the number of
 	entries currently stashed away.
diff --git a/Documentation/diff-config.txt b/Documentation/diff-config.txt
index 5ca942a..77caa66 100644
--- a/Documentation/diff-config.txt
+++ b/Documentation/diff-config.txt
@@ -112,7 +112,8 @@
 
 diff.renameLimit::
 	The number of files to consider when performing the copy/rename
-	detection; equivalent to the 'git diff' option `-l`.
+	detection; equivalent to the 'git diff' option `-l`. This setting
+	has no effect if rename detection is turned off.
 
 diff.renames::
 	Whether and how Git detects renames.  If set to "false",
diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index 8631e36..97d3217 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -188,6 +188,14 @@
 	is specified. This flag forces progress status even if the
 	standard error stream is not directed to a terminal.
 
+-o <option>::
+--server-option=<option>::
+	Transmit the given string to the server when communicating using
+	protocol version 2.  The given string must not contain a NUL or LF
+	character.
+	When multiple `--server-option=<option>` are given, they are all
+	sent to the other side in the order listed on the command line.
+
 -4::
 --ipv4::
 	Use IPv4 addresses only, ignoring IPv6 addresses.
diff --git a/Documentation/git-add.txt b/Documentation/git-add.txt
index d50fa33..45652fe 100644
--- a/Documentation/git-add.txt
+++ b/Documentation/git-add.txt
@@ -193,7 +193,7 @@
 	for command-line options).
 
 
-Configuration
+CONFIGURATION
 -------------
 
 The optional configuration variable `core.excludesFile` indicates a path to a
@@ -226,7 +226,7 @@
 listing the files explicitly), it does not consider
 `subdir/git-foo.sh`.
 
-Interactive mode
+INTERACTIVE MODE
 ----------------
 When the command enters the interactive mode, it shows the
 output of the 'status' subcommand, and then goes into its
diff --git a/Documentation/git-annotate.txt b/Documentation/git-annotate.txt
index 05fd482..e44a831 100644
--- a/Documentation/git-annotate.txt
+++ b/Documentation/git-annotate.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 [verse]
-'git annotate' [options] file [revision]
+'git annotate' [<options>] <file> [<revision>]
 
 DESCRIPTION
 -----------
diff --git a/Documentation/git-apply.txt b/Documentation/git-apply.txt
index 4ebc3d3..6722849 100644
--- a/Documentation/git-apply.txt
+++ b/Documentation/git-apply.txt
@@ -113,8 +113,10 @@
 linkgit:git-config[1]).
 
 -p<n>::
-	Remove <n> leading slashes from traditional diff paths. The
-	default is 1.
+	Remove <n> leading path components (separated by slashes) from
+	traditional diff paths. E.g., with `-p2`, a patch against
+	`a/dir/file` will be applied directly to `file`. The default is
+	1.
 
 -C<n>::
 	Ensure at least <n> lines of surrounding context match before
@@ -240,7 +242,7 @@
 the `--unsafe-paths` option to override this safety check.  This option
 has no effect when `--index` or `--cached` is in use.
 
-Configuration
+CONFIGURATION
 -------------
 
 apply.ignoreWhitespace::
@@ -251,7 +253,7 @@
 	When no `--whitespace` flag is given from the command
 	line, this configuration item is used as the default.
 
-Submodules
+SUBMODULES
 ----------
 If the patch contains any changes to submodules then 'git apply'
 treats these changes as follows.
diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index b3084c9..02eccbb 100644
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -287,7 +287,7 @@
 `--list` is used or implied. The default is to use a pager.
 See linkgit:git-config[1].
 
-Examples
+EXAMPLES
 --------
 
 Start development from a known tag::
@@ -318,7 +318,7 @@
 is currently checked out) does not have all commits from the test branch.
 
 
-Notes
+NOTES
 -----
 
 If you are creating a branch that you want to checkout immediately, it is
diff --git a/Documentation/git-bundle.txt b/Documentation/git-bundle.txt
index 3a8120c..7d6c9dc 100644
--- a/Documentation/git-bundle.txt
+++ b/Documentation/git-bundle.txt
@@ -92,8 +92,8 @@
 to contain objects already in the destination, as these are ignored
 when unpacking at the destination.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 Assume you want to transfer the history from a repository R1 on machine A
 to another repository R2 on machine B.
diff --git a/Documentation/git-check-attr.txt b/Documentation/git-check-attr.txt
index aa3b2bf..3c05782 100644
--- a/Documentation/git-check-attr.txt
+++ b/Documentation/git-check-attr.txt
@@ -9,8 +9,8 @@
 SYNOPSIS
 --------
 [verse]
-'git check-attr' [-a | --all | attr...] [--] pathname...
-'git check-attr' --stdin [-z] [-a | --all | attr...]
+'git check-attr' [-a | --all | <attr>...] [--] <pathname>...
+'git check-attr' --stdin [-z] [-a | --all | <attr>...]
 
 DESCRIPTION
 -----------
diff --git a/Documentation/git-check-ignore.txt b/Documentation/git-check-ignore.txt
index 611754f..8b42cb3 100644
--- a/Documentation/git-check-ignore.txt
+++ b/Documentation/git-check-ignore.txt
@@ -9,8 +9,8 @@
 SYNOPSIS
 --------
 [verse]
-'git check-ignore' [options] pathname...
-'git check-ignore' [options] --stdin
+'git check-ignore' [<options>] <pathname>...
+'git check-ignore' [<options>] --stdin
 
 DESCRIPTION
 -----------
diff --git a/Documentation/git-check-mailmap.txt b/Documentation/git-check-mailmap.txt
index 39028ee..aa2055d 100644
--- a/Documentation/git-check-mailmap.txt
+++ b/Documentation/git-check-mailmap.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git check-mailmap' [options] <contact>...
+'git check-mailmap' [<options>] <contact>...
 
 
 DESCRIPTION
diff --git a/Documentation/git-clone.txt b/Documentation/git-clone.txt
index 42ca7b5..a55536f 100644
--- a/Documentation/git-clone.txt
+++ b/Documentation/git-clone.txt
@@ -260,7 +260,7 @@
 
 <repository>::
 	The (possibly remote) repository to clone from.  See the
-	<<URLS,URLS>> section below for more information on specifying
+	<<URLS,GIT URLS>> section below for more information on specifying
 	repositories.
 
 <directory>::
@@ -273,7 +273,7 @@
 :git-clone: 1
 include::urls.txt[]
 
-Examples
+EXAMPLES
 --------
 
 * Clone from upstream:
diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt
new file mode 100644
index 0000000..4c97b55
--- /dev/null
+++ b/Documentation/git-commit-graph.txt
@@ -0,0 +1,94 @@
+git-commit-graph(1)
+===================
+
+NAME
+----
+git-commit-graph - Write and verify Git commit graph files
+
+
+SYNOPSIS
+--------
+[verse]
+'git commit-graph read' [--object-dir <dir>]
+'git commit-graph write' <options> [--object-dir <dir>]
+
+
+DESCRIPTION
+-----------
+
+Manage the serialized commit graph file.
+
+
+OPTIONS
+-------
+--object-dir::
+	Use given directory for the location of packfiles and commit graph
+	file. This parameter exists to specify the location of an alternate
+	that only has the objects directory, not a full .git directory. The
+	commit graph file is expected to be at <dir>/info/commit-graph and
+	the packfiles are expected to be in <dir>/pack.
+
+
+COMMANDS
+--------
+'write'::
+
+Write a commit graph file based on the commits found in packfiles.
++
+With the `--stdin-packs` option, generate the new commit graph by
+walking objects only in the specified pack-indexes. (Cannot be combined
+with --stdin-commits.)
++
+With the `--stdin-commits` option, generate the new commit graph by
+walking commits starting at the commits specified in stdin as a list
+of OIDs in hex, one OID per line. (Cannot be combined with
+--stdin-packs.)
++
+With the `--append` option, include all commits that are present in the
+existing commit-graph file.
+
+'read'::
+
+Read a graph file given by the commit-graph file and output basic
+details about the graph file. Used for debugging purposes.
+
+
+EXAMPLES
+--------
+
+* Write a commit graph file for the packed commits in your local .git folder.
++
+------------------------------------------------
+$ git commit-graph write
+------------------------------------------------
+
+* Write a graph file, extending the current graph file using commits
+* in <pack-index>.
++
+------------------------------------------------
+$ echo <pack-index> | git commit-graph write --stdin-packs
+------------------------------------------------
+
+* Write a graph file containing all reachable commits.
++
+------------------------------------------------
+$ git show-ref -s | git commit-graph write --stdin-commits
+------------------------------------------------
+
+* Write a graph file containing all commits in the current
+* commit-graph file along with those reachable from HEAD.
++
+------------------------------------------------
+$ git rev-parse HEAD | git commit-graph write --stdin-commits --append
+------------------------------------------------
+
+* Read basic information from the commit-graph file.
++
+------------------------------------------------
+$ git commit-graph read
+------------------------------------------------
+
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/git-config.txt b/Documentation/git-config.txt
index e09ed5d..18ddc78 100644
--- a/Documentation/git-config.txt
+++ b/Documentation/git-config.txt
@@ -9,13 +9,13 @@
 SYNOPSIS
 --------
 [verse]
-'git config' [<file-option>] [type] [--show-origin] [-z|--null] name [value [value_regex]]
-'git config' [<file-option>] [type] --add name value
-'git config' [<file-option>] [type] --replace-all name value [value_regex]
-'git config' [<file-option>] [type] [--show-origin] [-z|--null] --get name [value_regex]
-'git config' [<file-option>] [type] [--show-origin] [-z|--null] --get-all name [value_regex]
-'git config' [<file-option>] [type] [--show-origin] [-z|--null] [--name-only] --get-regexp name_regex [value_regex]
-'git config' [<file-option>] [type] [-z|--null] --get-urlmatch name URL
+'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] name [value [value_regex]]
+'git config' [<file-option>] [--type=<type>] --add name value
+'git config' [<file-option>] [--type=<type>] --replace-all name value [value_regex]
+'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] --get name [value_regex]
+'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] --get-all name [value_regex]
+'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] [--name-only] --get-regexp name_regex [value_regex]
+'git config' [<file-option>] [--type=<type>] [-z|--null] --get-urlmatch name URL
 'git config' [<file-option>] --unset name [value_regex]
 'git config' [<file-option>] --unset-all name [value_regex]
 'git config' [<file-option>] --rename-section old_name new_name
@@ -38,12 +38,10 @@
 you want to handle the lines that do *not* match the regex, just
 prepend a single exclamation mark in front (see also <<EXAMPLES>>).
 
-The type specifier can be either `--int` or `--bool`, to make
-'git config' ensure that the variable(s) are of the given type and
-convert the value to the canonical form (simple decimal number for int,
-a "true" or "false" string for bool), or `--path`, which does some
-path expansion (see `--path` below).  If no type specifier is passed, no
-checks or transformations are performed on the value.
+The `--type=<type>` option instructs 'git config' to ensure that incoming and
+outgoing values are canonicalize-able under the given <type>.  If no
+`--type=<type>` is given, no canonicalization will be performed. Callers may
+unset an existing `--type` specifier with `--no-type`.
 
 When reading, the values are read from the system, global and
 repository local configuration files by default, and options
@@ -160,30 +158,43 @@
 --list::
 	List all variables set in config file, along with their values.
 
+--type <type>::
+  'git config' will ensure that any input or output is valid under the given
+  type constraint(s), and will canonicalize outgoing values in `<type>`'s
+  canonical form.
++
+Valid `<type>`'s include:
++
+- 'bool': canonicalize values as either "true" or "false".
+- 'int': canonicalize values as simple decimal numbers. An optional suffix of
+  'k', 'm', or 'g' will cause the value to be multiplied by 1024, 1048576, or
+  1073741824 upon input.
+- 'bool-or-int': canonicalize according to either 'bool' or 'int', as described
+  above.
+- 'path': canonicalize by adding a leading `~` to the value of `$HOME` and
+  `~user` to the home directory for the specified user. This specifier has no
+  effect when setting the value (but you can use `git config section.variable
+  ~/` from the command line to let your shell do the expansion.)
+- 'expiry-date': canonicalize by converting from a fixed or relative date-string
+  to a timestamp. This specifier has no effect when setting the value.
+- 'color': When getting a value, canonicalize by converting to an ANSI color
+  escape sequence. When setting a value, a sanity-check is performed to ensure
+  that the given value is canonicalize-able as an ANSI color, but it is written
+  as-is.
++
+
 --bool::
-	'git config' will ensure that the output is "true" or "false"
-
 --int::
-	'git config' will ensure that the output is a simple
-	decimal number.  An optional value suffix of 'k', 'm', or 'g'
-	in the config file will cause the value to be multiplied
-	by 1024, 1048576, or 1073741824 prior to output.
-
 --bool-or-int::
-	'git config' will ensure that the output matches the format of
-	either --bool or --int, as described above.
-
 --path::
-	`git config` will expand a leading `~` to the value of
-	`$HOME`, and `~user` to the home directory for the
-	specified user.  This option has no effect when setting the
-	value (but you can use `git config section.variable ~/`
-	from the command line to let your shell do the expansion).
-
 --expiry-date::
-	`git config` will ensure that the output is converted from
-	a fixed or relative date-string to a timestamp. This option
-	has no effect when setting the value.
+  Historical options for selecting a type specifier. Prefer instead `--type`,
+  (see: above).
+
+--no-type::
+  Un-sets the previously set type specifier (if one was previously set). This
+  option requests that 'git config' not canonicalize the retrieved variable.
+  `--no-type` has no effect without `--type=<type>` or `--<type>`.
 
 -z::
 --null::
@@ -221,6 +232,8 @@
 	output it as the ANSI color escape sequence to the standard
 	output.  The optional `default` parameter is used instead, if
 	there is no color configured for `name`.
++
+`--type=color [--default=<default>]` is preferred over `--get-color`.
 
 -e::
 --edit::
@@ -233,6 +246,10 @@
 	using `--file`, `--global`, etc) and `on` when searching all
 	config files.
 
+--default <value>::
+  When using `--get`, and the requested variable is not found, behave as if
+  <value> were the value assigned to the that variable.
+
 CONFIGURATION
 -------------
 `pager.config` is only respected when listing configuration, i.e., when
diff --git a/Documentation/git-credential-cache.txt b/Documentation/git-credential-cache.txt
index 2b85826..0216c18 100644
--- a/Documentation/git-credential-cache.txt
+++ b/Documentation/git-credential-cache.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 -----------------------------
-git config credential.helper 'cache [options]'
+git config credential.helper 'cache [<options>]'
 -----------------------------
 
 DESCRIPTION
diff --git a/Documentation/git-credential-store.txt b/Documentation/git-credential-store.txt
index 25fb963..693dd9d 100644
--- a/Documentation/git-credential-store.txt
+++ b/Documentation/git-credential-store.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 -------------------
-git config credential.helper 'store [options]'
+git config credential.helper 'store [<options>]'
 -------------------
 
 DESCRIPTION
diff --git a/Documentation/git-cvsserver.txt b/Documentation/git-cvsserver.txt
index ba90066..f98b7c6 100644
--- a/Documentation/git-cvsserver.txt
+++ b/Documentation/git-cvsserver.txt
@@ -22,7 +22,7 @@
 Usage:
 
 [verse]
-'git-cvsserver' [options] [pserver|server] [<directory> ...]
+'git-cvsserver' [<options>] [pserver|server] [<directory> ...]
 
 OPTIONS
 -------
@@ -207,7 +207,7 @@
 ------
 
 [[dbbackend]]
-Database Backend
+DATABASE BACKEND
 ----------------
 
 'git-cvsserver' uses one database per Git head (i.e. CVS module) to
@@ -321,7 +321,7 @@
 When these environment variables are set, the corresponding
 command-line arguments may not be used.
 
-Eclipse CVS Client Notes
+ECLIPSE CVS CLIENT NOTES
 ------------------------
 
 To get a checkout with the Eclipse CVS client:
@@ -346,7 +346,7 @@
 the cvs utility on the server with 'git-cvsserver' or manipulate your `.bashrc`
 so that calling 'cvs' effectively calls 'git-cvsserver'.
 
-Clients known to work
+CLIENTS KNOWN TO WORK
 ---------------------
 
 - CVS 1.12.9 on Debian
@@ -354,7 +354,7 @@
 - Eclipse 3.0, 3.1.2 on MacOSX (see Eclipse CVS Client Notes)
 - TortoiseCVS
 
-Operations supported
+OPERATIONS SUPPORTED
 --------------------
 
 All the operations required for normal use are supported, including
@@ -424,7 +424,7 @@
 defaults by setting `gitcvs.usecrlfattr` to true,
 and `gitcvs.allBinary` to "guess".
 
-Dependencies
+DEPENDENCIES
 ------------
 'git-cvsserver' depends on DBD::SQLite.
 
diff --git a/Documentation/git-diff-index.txt b/Documentation/git-diff-index.txt
index b380677..f4bd815 100644
--- a/Documentation/git-diff-index.txt
+++ b/Documentation/git-diff-index.txt
@@ -37,14 +37,14 @@
 
 include::diff-format.txt[]
 
-Operating Modes
+OPERATING MODES
 ---------------
 You can choose whether you want to trust the index file entirely
 (using the `--cached` flag) or ask the diff logic to show any files
 that don't match the stat state as being "tentatively changed".  Both
 of these operations are very useful indeed.
 
-Cached Mode
+CACHED MODE
 -----------
 If `--cached` is specified, it allows you to ask:
 
@@ -77,7 +77,7 @@
 asking yourself "what have I already marked for being committed, and
 what's the difference to a previous tree".
 
-Non-cached Mode
+NON-CACHED MODE
 ---------------
 The "non-cached" mode takes a different approach, and is potentially
 the more useful of the two in that what it does can't be emulated with
diff --git a/Documentation/git-diff-tree.txt b/Documentation/git-diff-tree.txt
index 7870e17..2319b2b 100644
--- a/Documentation/git-diff-tree.txt
+++ b/Documentation/git-diff-tree.txt
@@ -116,7 +116,7 @@
 include::pretty-formats.txt[]
 
 
-Limiting Output
+LIMITING OUTPUT
 ---------------
 If you're only interested in differences in a subset of files, for
 example some architecture-specific files, you might do:
diff --git a/Documentation/git-diff.txt b/Documentation/git-diff.txt
index b0c1bb9..b180f1f 100644
--- a/Documentation/git-diff.txt
+++ b/Documentation/git-diff.txt
@@ -9,11 +9,11 @@
 SYNOPSIS
 --------
 [verse]
-'git diff' [options] [<commit>] [--] [<path>...]
-'git diff' [options] --cached [<commit>] [--] [<path>...]
-'git diff' [options] <commit> <commit> [--] [<path>...]
-'git diff' [options] <blob> <blob>
-'git diff' [options] [--no-index] [--] <path> <path>
+'git diff' [<options>] [<commit>] [--] [<path>...]
+'git diff' [<options>] --cached [<commit>] [--] [<path>...]
+'git diff' [<options>] <commit> <commit> [--] [<path>...]
+'git diff' [<options>] <blob> <blob>
+'git diff' [<options>] --no-index [--] <path> <path>
 
 DESCRIPTION
 -----------
@@ -21,7 +21,7 @@
 between the index and a tree, changes between two trees, changes between
 two blob objects, or changes between two files on disk.
 
-'git diff' [--options] [--] [<path>...]::
+'git diff' [<options>] [--] [<path>...]::
 
 	This form is to view the changes you made relative to
 	the index (staging area for the next commit).  In other
@@ -29,7 +29,7 @@
 	further add to the index but you still haven't.  You can
 	stage these changes by using linkgit:git-add[1].
 
-'git diff' --no-index [--options] [--] [<path>...]::
+'git diff' [<options>] --no-index [--] <path> <path>::
 
 	This form is to compare the given two paths on the
 	filesystem.  You can omit the `--no-index` option when
@@ -38,7 +38,7 @@
 	or when running the command outside a working tree
 	controlled by Git.
 
-'git diff' [--options] --cached [<commit>] [--] [<path>...]::
+'git diff' [<options>] --cached [<commit>] [--] [<path>...]::
 
 	This form is to view the changes you staged for the next
 	commit relative to the named <commit>.  Typically you
@@ -48,7 +48,7 @@
 	<commit> is not given, it shows all staged changes.
 	--staged is a synonym of --cached.
 
-'git diff' [--options] <commit> [--] [<path>...]::
+'git diff' [<options>] <commit> [--] [<path>...]::
 
 	This form is to view the changes you have in your
 	working tree relative to the named <commit>.  You can
@@ -56,18 +56,18 @@
 	branch name to compare with the tip of a different
 	branch.
 
-'git diff' [--options] <commit> <commit> [--] [<path>...]::
+'git diff' [<options>] <commit> <commit> [--] [<path>...]::
 
 	This is to view the changes between two arbitrary
 	<commit>.
 
-'git diff' [--options] <commit>..<commit> [--] [<path>...]::
+'git diff' [<options>] <commit>..<commit> [--] [<path>...]::
 
 	This is synonymous to the previous form.  If <commit> on
 	one side is omitted, it will have the same effect as
 	using HEAD instead.
 
-'git diff' [--options] <commit>\...<commit> [--] [<path>...]::
+'git diff' [<options>] <commit>\...<commit> [--] [<path>...]::
 
 	This form is to view the changes on the branch containing
 	and up to the second <commit>, starting at a common ancestor
@@ -87,7 +87,7 @@
 "<commit>\...<commit>") do not mean a range as defined in the
 "SPECIFYING RANGES" section in linkgit:gitrevisions[7].
 
-'git diff' [options] <blob> <blob>::
+'git diff' [<options>] <blob> <blob>::
 
 	This form is to view the differences between the raw
 	contents of two blob objects.
diff --git a/Documentation/git-fast-export.txt b/Documentation/git-fast-export.txt
index ed57c68..ce954be 100644
--- a/Documentation/git-fast-export.txt
+++ b/Documentation/git-fast-export.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git fast-export [options]' | 'git fast-import'
+'git fast-export [<options>]' | 'git fast-import'
 
 DESCRIPTION
 -----------
@@ -202,7 +202,7 @@
 no private data in the stream.
 
 
-Limitations
+LIMITATIONS
 -----------
 
 Since 'git fast-import' cannot tag trees, you will not be
diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 3d3d219..e81117d 100644
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-frontend | 'git fast-import' [options]
+frontend | 'git fast-import' [<options>]
 
 DESCRIPTION
 -----------
@@ -139,7 +139,7 @@
 fastimport.unpackLimit::
 	See linkgit:git-config[1]
 
-Performance
+PERFORMANCE
 -----------
 The design of fast-import allows it to import large projects in a minimum
 amount of memory usage and processing time.  Assuming the frontend
@@ -155,7 +155,7 @@
 destination Git repository (due to less IO contention).
 
 
-Development Cost
+DEVELOPMENT COST
 ----------------
 A typical frontend for fast-import tends to weigh in at approximately 200
 lines of Perl/Python/Ruby code.  Most developers have been able to
@@ -165,7 +165,7 @@
 (use once, and never look back).
 
 
-Parallel Operation
+PARALLEL OPERATION
 ------------------
 Like 'git push' or 'git fetch', imports handled by fast-import are safe to
 run alongside parallel `git repack -a -d` or `git gc` invocations,
@@ -186,7 +186,7 @@
 is not necessary for an initial import into an empty repository.
 
 
-Technical Discussion
+TECHNICAL DISCUSSION
 --------------------
 fast-import tracks a set of branches in memory.  Any branch can be created
 or modified at any point during the import process by sending a
@@ -204,7 +204,7 @@
 need to perform any costly file update operations when switching
 between branches.
 
-Input Format
+INPUT FORMAT
 ------------
 With the exception of raw file data (which Git does not interpret)
 the fast-import input format is text (ASCII) based.  This text based
@@ -1131,7 +1131,7 @@
 in use, the `done` command is mandatory and marks the end of the
 stream.
 
-Responses To Commands
+RESPONSES TO COMMANDS
 ---------------------
 New objects written by fast-import are not available immediately.
 Most fast-import commands have no visible effect until the next
@@ -1160,7 +1160,7 @@
 pending output from `progress`, `ls`, `get-mark`, and `cat-blob` before
 performing writes to fast-import that might block.
 
-Crash Reports
+CRASH REPORTS
 -------------
 If fast-import is supplied invalid input it will terminate with a
 non-zero exit status and create a crash report in the top level of
@@ -1247,7 +1247,7 @@
 	END OF CRASH REPORT
 ====
 
-Tips and Tricks
+TIPS AND TRICKS
 ---------------
 The following tips and tricks have been collected from various
 users of fast-import, and are offered here as suggestions.
@@ -1349,7 +1349,7 @@
 has been processed.
 
 
-Packfile Optimization
+PACKFILE OPTIMIZATION
 ---------------------
 When packing a blob fast-import always attempts to deltify against the last
 blob written.  Unless specifically arranged for by the frontend,
@@ -1380,7 +1380,7 @@
 final packfile size (30-50% smaller can be quite typical).
 
 
-Memory Utilization
+MEMORY UTILIZATION
 ------------------
 There are a number of factors which affect how much memory fast-import
 requires to perform an import.  Like critical sections of core
@@ -1458,7 +1458,7 @@
 projects with 2,000+ branches and 45,114+ files in a very limited
 memory footprint (less than 2.7 MiB per active branch).
 
-Signals
+SIGNALS
 -------
 Sending *SIGUSR1* to the 'git fast-import' process ends the current
 packfile early, simulating a `checkpoint` command.  The impatient
diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt
index b634043..e6f08ab 100644
--- a/Documentation/git-filter-branch.txt
+++ b/Documentation/git-filter-branch.txt
@@ -230,7 +230,7 @@
 any other non-zero value.
 
 
-Examples
+EXAMPLES
 --------
 
 Suppose you want to remove a file (containing confidential information
@@ -288,7 +288,7 @@
 or even simpler:
 
 -----------------------------------------------
-echo "$commit-id $graft-id" >> .git/info/grafts
+git replace --graft $commit-id $graft-id
 git filter-branch $graft-id..HEAD
 -----------------------------------------------
 
@@ -406,7 +406,7 @@
 
 
 
-Checklist for Shrinking a Repository
+CHECKLIST FOR SHRINKING A REPOSITORY
 ------------------------------------
 
 git-filter-branch can be used to get rid of a subset of files,
@@ -445,7 +445,7 @@
   (or if your git-gc is not new enough to support arguments to
   `--prune`, use `git repack -ad; git prune` instead).
 
-Notes
+NOTES
 -----
 
 git-filter-branch allows you to make complex shell-scripted rewrites
diff --git a/Documentation/git-fmt-merge-msg.txt b/Documentation/git-fmt-merge-msg.txt
index 44892c4..423b6e0 100644
--- a/Documentation/git-fmt-merge-msg.txt
+++ b/Documentation/git-fmt-merge-msg.txt
@@ -57,8 +57,8 @@
 	Synonym to `merge.log`; this is deprecated and will be removed in
 	the future.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 ---------
 $ git fetch origin master
diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index 6cbe462..b41e132 100644
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -47,7 +47,7 @@
 
 The first rule takes precedence in the case of a single <commit>.  To
 apply the second rule, i.e., format everything since the beginning of
-history up until <commit>, use the '\--root' option: `git format-patch
+history up until <commit>, use the `--root` option: `git format-patch
 --root <commit>`.  If you want to format only <commit> itself, you
 can do this with `git format-patch -1 <commit>`.
 
diff --git a/Documentation/git-gc.txt b/Documentation/git-gc.txt
index 3126e0d..24b2dd4 100644
--- a/Documentation/git-gc.txt
+++ b/Documentation/git-gc.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git gc' [--aggressive] [--auto] [--quiet] [--prune=<date> | --no-prune] [--force]
+'git gc' [--aggressive] [--auto] [--quiet] [--prune=<date> | --no-prune] [--force] [--keep-largest-pack]
 
 DESCRIPTION
 -----------
@@ -56,10 +56,16 @@
 to 0 disables automatic packing of loose objects.
 +
 If the number of packs exceeds the value of `gc.autoPackLimit`,
-then existing packs (except those marked with a `.keep` file)
+then existing packs (except those marked with a `.keep` file
+or over `gc.bigPackThreshold` limit)
 are consolidated into a single pack by using the `-A` option of
-'git repack'. Setting `gc.autoPackLimit` to 0 disables
-automatic consolidation of packs.
+'git repack'.
+If the amount of memory is estimated not enough for `git repack` to
+run smoothly and `gc.bigPackThreshold` is not set, the largest
+pack will also be excluded (this is the equivalent of running `git gc`
+with `--keep-base-pack`).
+Setting `gc.autoPackLimit` to 0 disables automatic consolidation of
+packs.
 +
 If houskeeping is required due to many loose objects or packs, all
 other housekeeping tasks (e.g. rerere, working trees, reflog...) will
@@ -84,7 +90,12 @@
 	Force `git gc` to run even if there may be another `git gc`
 	instance running on this repository.
 
-Configuration
+--keep-largest-pack::
+	All packs except the largest pack and those marked with a
+	`.keep` files are consolidated into a single pack. When this
+	option is used, `gc.bigPackThreshold` is ignored.
+
+CONFIGURATION
 -------------
 
 The optional configuration variable `gc.reflogExpire` can be
@@ -129,7 +140,7 @@
 much time is spent optimizing the delta compression of the objects in
 the repository when the --aggressive option is specified.  The larger
 the value, the more time is spent optimizing the delta compression.  See
-the documentation for the --window' option in linkgit:git-repack[1] for
+the documentation for the --window option in linkgit:git-repack[1] for
 more details.  This defaults to 250.
 
 Similarly, the optional configuration variable `gc.aggressiveDepth`
@@ -144,7 +155,7 @@
 it. Default is "3 months ago".
 
 
-Notes
+NOTES
 -----
 
 'git gc' tries very hard not to delete objects that are referenced
diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
index 18b4947..312409a 100644
--- a/Documentation/git-grep.txt
+++ b/Documentation/git-grep.txt
@@ -293,7 +293,7 @@
 For more details about the <pathspec> syntax, see the 'pathspec' entry
 in linkgit:gitglossary[7].
 
-Examples
+EXAMPLES
 --------
 
 `git grep 'time_t' -- '*.[ch]'`::
diff --git a/Documentation/git-help.txt b/Documentation/git-help.txt
index 40d328a..a40fc38 100644
--- a/Documentation/git-help.txt
+++ b/Documentation/git-help.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 [verse]
-'git help' [-a|--all] [-g|--guide]
+'git help' [-a|--all [--verbose]] [-g|--guide]
 	   [-i|--info|-m|--man|-w|--web] [COMMAND|GUIDE]
 
 DESCRIPTION
@@ -42,6 +42,8 @@
 --all::
 	Prints all the available commands on the standard output. This
 	option overrides any given command or guide name.
+	When used with `--verbose` print description for all recognized
+	commands.
 
 -g::
 --guides::
diff --git a/Documentation/git-http-fetch.txt b/Documentation/git-http-fetch.txt
index 21a33d2..666b042 100644
--- a/Documentation/git-http-fetch.txt
+++ b/Documentation/git-http-fetch.txt
@@ -15,8 +15,9 @@
 -----------
 Downloads a remote Git repository via HTTP.
 
-*NOTE*: use of this command without -a is deprecated.  The -a
-behaviour will become the default in a future release.
+This command always gets all objects. Historically, there were three options
+`-a`, `-c` and `-t` for choosing which objects to download. They are now
+silently ignored.
 
 OPTIONS
 -------
@@ -24,12 +25,8 @@
         Either the hash or the filename under [URL]/refs/ to
         pull.
 
--c::
-	Get the commit objects.
--t::
-	Get trees associated with the commit objects.
--a::
-	Get all the objects.
+-a, -c, -t::
+	These options are ignored for historical reasons.
 -v::
 	Report what is downloaded.
 
diff --git a/Documentation/git-http-push.txt b/Documentation/git-http-push.txt
index 2aceb6f..ea03a4e 100644
--- a/Documentation/git-http-push.txt
+++ b/Documentation/git-http-push.txt
@@ -55,7 +55,7 @@
 	The remote refs to update.
 
 
-Specifying the Refs
+SPECIFYING THE REFS
 -------------------
 
 A '<ref>' specification can be either a single pattern, or a pair
diff --git a/Documentation/git-imap-send.txt b/Documentation/git-imap-send.txt
index 5d1e4c8..032613c 100644
--- a/Documentation/git-imap-send.txt
+++ b/Documentation/git-imap-send.txt
@@ -136,8 +136,8 @@
 .........................
 
 
-EXAMPLE
--------
+EXAMPLES
+--------
 To submit patches using GMail's IMAP interface, first, edit your ~/.gitconfig
 to specify your account settings:
 
diff --git a/Documentation/git-index-pack.txt b/Documentation/git-index-pack.txt
index 138edb4..d5b7560 100644
--- a/Documentation/git-index-pack.txt
+++ b/Documentation/git-index-pack.txt
@@ -93,8 +93,8 @@
 --max-input-size=<size>::
 	Die, if the pack is larger than <size>.
 
-Note
-----
+NOTES
+-----
 
 Once the index has been created, the list of object names is sorted
 and the SHA-1 hash of that list is printed to stdout. If --stdin was
diff --git a/Documentation/git-interpret-trailers.txt b/Documentation/git-interpret-trailers.txt
index ff446f1..9111c47 100644
--- a/Documentation/git-interpret-trailers.txt
+++ b/Documentation/git-interpret-trailers.txt
@@ -8,8 +8,8 @@
 SYNOPSIS
 --------
 [verse]
-'git interpret-trailers' [options] [(--trailer <token>[(=|:)<value>])...] [<file>...]
-'git interpret-trailers' [options] [--parse] [<file>...]
+'git interpret-trailers' [<options>] [(--trailer <token>[(=|:)<value>])...] [<file>...]
+'git interpret-trailers' [<options>] [--parse] [<file>...]
 
 DESCRIPTION
 -----------
diff --git a/Documentation/git-log.txt b/Documentation/git-log.txt
index 5437f8b..90761f1 100644
--- a/Documentation/git-log.txt
+++ b/Documentation/git-log.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git log' [<options>] [<revision range>] [[\--] <path>...]
+'git log' [<options>] [<revision range>] [[--] <path>...]
 
 DESCRIPTION
 -----------
@@ -90,13 +90,13 @@
 	ways to spell <revision range>, see the 'Specifying Ranges'
 	section of linkgit:gitrevisions[7].
 
-[\--] <path>...::
+[--] <path>...::
 	Show only commits that are enough to explain how the files
 	that match the specified paths came to be.  See 'History
 	Simplification' below for details and other simplification
 	modes.
 +
-Paths may need to be prefixed with ``\-- '' to separate them from
+Paths may need to be prefixed with `--` to separate them from
 options or the revision range, when confusion arises.
 
 include::rev-list-options.txt[]
@@ -125,7 +125,7 @@
 `git log --since="2 weeks ago" -- gitk`::
 
 	Show the changes during the last two weeks to the file 'gitk'.
-	The ``--'' is necessary to avoid confusion with the *branch* named
+	The `--` is necessary to avoid confusion with the *branch* named
 	'gitk'
 
 `git log --name-status release..test`::
diff --git a/Documentation/git-ls-files.txt b/Documentation/git-ls-files.txt
index 3ac3e3a..5298f1b 100644
--- a/Documentation/git-ls-files.txt
+++ b/Documentation/git-ls-files.txt
@@ -53,7 +53,8 @@
 	Show only ignored files in the output. When showing files in the
 	index, print only those matched by an exclude pattern. When
 	showing "other" files, show only those matched by an exclude
-	pattern.
+	pattern. Standard ignore rules are not automatically activated,
+	therefore at least one of the `--exclude*` options is required.
 
 -s::
 --stage::
@@ -183,7 +184,7 @@
 	Files to show. If no files are given all files which match the other
 	specified criteria are shown.
 
-Output
+OUTPUT
 ------
 'git ls-files' just outputs the filenames unless `--stage` is specified in
 which case it outputs:
@@ -208,7 +209,7 @@
 verbatim and the line is terminated by a NUL byte.
 
 
-Exclude Patterns
+EXCLUDE PATTERNS
 ----------------
 
 'git ls-files' can use a list of "exclude patterns" when
diff --git a/Documentation/git-ls-remote.txt b/Documentation/git-ls-remote.txt
index 5f2628c..b9fd377 100644
--- a/Documentation/git-ls-remote.txt
+++ b/Documentation/git-ls-remote.txt
@@ -10,7 +10,7 @@
 --------
 [verse]
 'git ls-remote' [--heads] [--tags] [--refs] [--upload-pack=<exec>]
-	      [-q | --quiet] [--exit-code] [--get-url]
+	      [-q | --quiet] [--exit-code] [--get-url] [--sort=<key>]
 	      [--symref] [<repository> [<refs>...]]
 
 DESCRIPTION
@@ -60,6 +60,24 @@
 	upload-pack only shows the symref HEAD, so it will be the only
 	one shown by ls-remote.
 
+--sort=<key>::
+	Sort based on the key given. Prefix `-` to sort in descending order
+	of the value. Supports "version:refname" or "v:refname" (tag names
+	are treated as versions). The "version:refname" sort order can also
+	be affected by the "versionsort.suffix" configuration variable.
+	See linkgit:git-for-each-ref[1] for more sort options, but be aware
+	keys like `committerdate` that require access to the objects
+	themselves will not work for refs whose objects have not yet been
+	fetched from the remote, and will give a `missing object` error.
+
+-o <option>::
+--server-option=<option>::
+	Transmit the given string to the server when communicating using
+	protocol version 2.  The given string must not contain a NUL or LF
+	character.
+	When multiple `--server-option=<option>` are given, they are all
+	sent to the other side in the order listed on the command line.
+
 <repository>::
 	The "remote" repository to query.  This parameter can be
 	either a URL or the name of a remote (see the GIT URLS and
@@ -90,6 +108,10 @@
 	c5db5456ae3b0873fc659c19fafdde22313cc441	refs/tags/v0.99.2
 	7ceca275d047c90c0c7d5afb13ab97efdf51bd6e	refs/tags/v0.99.3
 
+SEE ALSO
+--------
+linkgit:git-check-ref-format[1].
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/git-name-rev.txt b/Documentation/git-name-rev.txt
index e8e68f5..5cb0eb0 100644
--- a/Documentation/git-name-rev.txt
+++ b/Documentation/git-name-rev.txt
@@ -61,8 +61,8 @@
 --always::
 	Show uniquely abbreviated commit object as fallback.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 Given a commit, find out where it is relative to the local refs. Say somebody
 wrote you about that fantastic commit 33db5f4d9027a10e477ccf054b2c1ab94f74c85a.
diff --git a/Documentation/git-p4.txt b/Documentation/git-p4.txt
index d8c8f11..b9feceb 100644
--- a/Documentation/git-p4.txt
+++ b/Documentation/git-p4.txt
@@ -29,8 +29,8 @@
 the updated p4 remote branch.
 
 
-EXAMPLE
--------
+EXAMPLES
+--------
 * Clone a repository:
 +
 ------------
@@ -164,6 +164,31 @@
 $ git p4 submit --update-shelve 1234 --update-shelve 2345
 ----
 
+
+Unshelve
+~~~~~~~~
+Unshelving will take a shelved P4 changelist, and produce the equivalent git commit
+in the branch refs/remotes/p4/unshelved/<changelist>.
+
+The git commit is created relative to the current origin revision (HEAD by default).
+If the shelved changelist's parent revisions differ, git-p4 will refuse to unshelve;
+you need to be unshelving onto an equivalent tree.
+
+The origin revision can be changed with the "--origin" option.
+
+If the target branch in refs/remotes/p4/unshelved already exists, the old one will
+be renamed.
+
+----
+$ git p4 sync
+$ git p4 unshelve 12345
+$ git show refs/remotes/p4/unshelved/12345
+<submit more changes via p4 to the same files>
+$ git p4 unshelve 12345
+<refuses to unshelve until git is in sync with p4 again>
+
+----
+
 OPTIONS
 -------
 
@@ -337,6 +362,13 @@
 --import-labels::
 	Import p4 labels.
 
+Unshelve options
+~~~~~~~~~~~~~~~~
+
+--origin::
+    Sets the git refspec against which the shelved P4 changelist is compared.
+    Defaults to p4/master.
+
 DEPOT PATH SYNTAX
 -----------------
 The p4 depot path argument to 'git p4 sync' and 'git p4 clone' can
@@ -392,7 +424,7 @@
 The name of the client can be given to 'git p4' in multiple ways.  The
 variable 'git-p4.client' takes precedence if it exists.  Otherwise,
 normal p4 mechanisms of determining the client are used:  environment
-variable P4CLIENT, a file referenced by P4CONFIG, or the local host name.
+variable `P4CLIENT`, a file referenced by `P4CONFIG`, or the local host name.
 
 
 BRANCH DETECTION
@@ -461,22 +493,22 @@
 ~~~~~~~~~~~~~~~~~
 git-p4.user::
 	User specified as an option to all p4 commands, with '-u <user>'.
-	The environment variable 'P4USER' can be used instead.
+	The environment variable `P4USER` can be used instead.
 
 git-p4.password::
 	Password specified as an option to all p4 commands, with
 	'-P <password>'.
-	The environment variable 'P4PASS' can be used instead.
+	The environment variable `P4PASS` can be used instead.
 
 git-p4.port::
 	Port specified as an option to all p4 commands, with
 	'-p <port>'.
-	The environment variable 'P4PORT' can be used instead.
+	The environment variable `P4PORT` can be used instead.
 
 git-p4.host::
 	Host specified as an option to all p4 commands, with
 	'-h <host>'.
-	The environment variable 'P4HOST' can be used instead.
+	The environment variable `P4HOST` can be used instead.
 
 git-p4.client::
 	Client specified as an option to all p4 commands, with
diff --git a/Documentation/git-pack-objects.txt b/Documentation/git-pack-objects.txt
index 81bc490..d95b472 100644
--- a/Documentation/git-pack-objects.txt
+++ b/Documentation/git-pack-objects.txt
@@ -12,7 +12,7 @@
 'git pack-objects' [-q | --progress | --all-progress] [--all-progress-implied]
 	[--no-reuse-delta] [--delta-base-offset] [--non-empty]
 	[--local] [--incremental] [--window=<n>] [--depth=<n>]
-	[--revs [--unpacked | --all]]
+	[--revs [--unpacked | --all]] [--keep-pack=<pack-name>]
 	[--stdout [--filter=<filter-spec>] | base-name]
 	[--shallow] [--keep-true-parents] < object-list
 
@@ -96,7 +96,9 @@
 	it too deep affects the performance on the unpacker
 	side, because delta data needs to be applied that many
 	times to get to the necessary object.
-	The default value for --window is 10 and --depth is 50.
++
+The default value for --window is 10 and --depth is 50. The maximum
+depth is 4095.
 
 --window-memory=<n>::
 	This option provides an additional limit on top of `--window`;
@@ -126,6 +128,13 @@
 	has a .keep file to be ignored, even if it would have
 	otherwise been packed.
 
+--keep-pack=<pack-name>::
+	This flag causes an object already in the given pack to be
+	ignored, even if it would have otherwise been
+	packed. `<pack-name>` is the the pack file name without
+	leading directory (e.g. `pack-123.pack`). The option could be
+	specified multiple times to keep multiple packs.
+
 --incremental::
 	This flag causes an object already in a pack to be ignored
 	even if it would have otherwise been packed.
@@ -267,6 +276,19 @@
 	locally created objects [without .promisor] and objects from the
 	promisor remote [with .promisor].)  This is used with partial clone.
 
+--keep-unreachable::
+	Objects unreachable from the refs in packs named with
+	--unpacked= option are added to the resulting pack, in
+	addition to the reachable objects that are not in packs marked
+	with *.keep files. This implies `--revs`.
+
+--pack-loose-unreachable::
+	Pack unreachable loose objects (and their loose counterparts
+	removed). This implies `--revs`.
+
+--unpack-unreachable::
+	Keep unreachable objects in loose form. This implies `--revs`.
+
 SEE ALSO
 --------
 linkgit:git-rev-list[1]
diff --git a/Documentation/git-prune.txt b/Documentation/git-prune.txt
index a37c0af..03552dd 100644
--- a/Documentation/git-prune.txt
+++ b/Documentation/git-prune.txt
@@ -56,8 +56,8 @@
 	reachable from any of our references, keep objects
 	reachable from listed <head>s.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 To prune objects not used by your repository or another that
 borrows from your repository via its
@@ -67,7 +67,7 @@
 $ git prune $(cd ../another && git rev-parse --all)
 ------------
 
-Notes
+NOTES
 -----
 
 In most cases, users will not need to call 'git prune' directly, but
diff --git a/Documentation/git-pull.txt b/Documentation/git-pull.txt
index 4e0ad6f..118d9d8 100644
--- a/Documentation/git-pull.txt
+++ b/Documentation/git-pull.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git pull' [options] [<repository> [<refspec>...]]
+'git pull' [<options>] [<repository> [<refspec>...]]
 
 
 DESCRIPTION
diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt
index 5b08302..55277a9 100644
--- a/Documentation/git-push.txt
+++ b/Documentation/git-push.txt
@@ -11,7 +11,7 @@
 [verse]
 'git push' [--all | --mirror | --tags] [--follow-tags] [--atomic] [-n | --dry-run] [--receive-pack=<git-receive-pack>]
 	   [--repo=<repository>] [-f | --force] [-d | --delete] [--prune] [-v | --verbose]
-	   [-u | --set-upstream] [--push-option=<string>]
+	   [-u | --set-upstream] [-o <string> | --push-option=<string>]
 	   [--[no-]signed|--signed=(true|false|if-asked)]
 	   [--force-with-lease[=<refname>[:<expect>]]]
 	   [--no-verify] [<repository> [<refspec>...]]
@@ -123,6 +123,7 @@
 	will be tab-separated and sent to stdout instead of stderr.  The full
 	symbolic names of the refs will be given.
 
+-d::
 --delete::
 	All listed refs are deleted from the remote repository. This is
 	the same as prefixing all refs with a colon.
@@ -300,7 +301,7 @@
 	These options are passed to linkgit:git-send-pack[1]. A thin transfer
 	significantly reduces the amount of sent data when the sender and
 	receiver share many of the same objects in common. The default is
-	\--thin.
+	`--thin`.
 
 -q::
 --quiet::
@@ -423,7 +424,7 @@
 	refs, no explanation is needed. For a failed ref, the reason for
 	failure is described.
 
-Note about fast-forwards
+NOTE ABOUT FAST-FORWARDS
 ------------------------
 
 When an update changes a branch (or more in general, a ref) that used to
@@ -510,7 +511,7 @@
 a case where you do mean to lose history.
 
 
-Examples
+EXAMPLES
 --------
 
 `git push`::
diff --git a/Documentation/git-read-tree.txt b/Documentation/git-read-tree.txt
index f2a07d5..5c70bc2 100644
--- a/Documentation/git-read-tree.txt
+++ b/Documentation/git-read-tree.txt
@@ -132,7 +132,7 @@
 	The id of the tree object(s) to be read/merged.
 
 
-Merging
+MERGING
 -------
 If `-m` is specified, 'git read-tree' can perform 3 kinds of
 merge, a single tree merge if only 1 tree is given, a
@@ -382,7 +382,7 @@
 have finished your work-in-progress), attempt the merge again.
 
 
-Sparse checkout
+SPARSE CHECKOUT
 ---------------
 
 "Sparse checkout" allows populating the working directory sparsely.
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index bd5ecff..0e20a66 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -8,9 +8,9 @@
 SYNOPSIS
 --------
 [verse]
-'git rebase' [-i | --interactive] [options] [--exec <cmd>] [--onto <newbase>]
+'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] [--onto <newbase>]
 	[<upstream> [<branch>]]
-'git rebase' [-i | --interactive] [options] [--exec <cmd>] [--onto <newbase>]
+'git rebase' [-i | --interactive] [<options>] [--exec <cmd>] [--onto <newbase>]
 	--root [<branch>]
 'git rebase' --continue | --skip | --abort | --quit | --edit-todo | --show-current-patch
 
diff --git a/Documentation/git-receive-pack.txt b/Documentation/git-receive-pack.txt
index 86a4b32..dedf97e 100644
--- a/Documentation/git-receive-pack.txt
+++ b/Documentation/git-receive-pack.txt
@@ -41,7 +41,7 @@
 <directory>::
 	The repository to sync into.
 
-pre-receive Hook
+PRE-RECEIVE HOOK
 ----------------
 Before any ref is updated, if $GIT_DIR/hooks/pre-receive file exists
 and is executable, it will be invoked once with no parameters.  The
@@ -116,7 +116,7 @@
 
 See the notes on the quarantine environment below.
 
-update Hook
+UPDATE HOOK
 -----------
 Before each ref is updated, if $GIT_DIR/hooks/update file exists
 and is executable, it is invoked once per ref, with three parameters:
@@ -138,7 +138,7 @@
 As such it is not a good idea to send notices (e.g. email) from
 this hook.  Consider using the post-receive hook instead.
 
-post-receive Hook
+POST-RECEIVE HOOK
 -----------------
 After all refs were updated (or attempted to be updated), if any
 ref update was successful, and if $GIT_DIR/hooks/post-receive
@@ -198,7 +198,7 @@
 to evaluate it.  It is recommended that hooks rely on sha1-new
 rather than the current value of refname.
 
-post-update Hook
+POST-UPDATE HOOK
 ----------------
 After all other processing, if at least one ref was updated, and
 if $GIT_DIR/hooks/post-update file exists and is executable, then
@@ -216,7 +216,7 @@
 	exec git update-server-info
 
 
-Quarantine Environment
+QUARANTINE ENVIRONMENT
 ----------------------
 
 When `receive-pack` takes in objects, they are placed into a temporary
diff --git a/Documentation/git-remote-ext.txt b/Documentation/git-remote-ext.txt
index b25d0b5..3fc5d94 100644
--- a/Documentation/git-remote-ext.txt
+++ b/Documentation/git-remote-ext.txt
@@ -55,14 +55,14 @@
 	the vhost field in the git:// service request (to rest of the argument).
 	Default is not to send vhost in such request (if sent).
 
-ENVIRONMENT VARIABLES:
-----------------------
+ENVIRONMENT VARIABLES
+---------------------
 
 GIT_TRANSLOOP_DEBUG::
 	If set, prints debugging information about various reads/writes.
 
-ENVIRONMENT VARIABLES PASSED TO COMMAND:
-----------------------------------------
+ENVIRONMENT VARIABLES PASSED TO COMMAND
+---------------------------------------
 
 GIT_EXT_SERVICE::
 	Set to long name (git-upload-pack, etc...) of service helper needs
@@ -73,8 +73,8 @@
 	to invoke.
 
 
-EXAMPLES:
----------
+EXAMPLES
+--------
 This remote helper is transparently used by Git when
 you use commands such as "git fetch <URL>", "git clone <URL>",
 , "git push <URL>" or "git remote add <nick> <URL>", where <URL>
diff --git a/Documentation/git-remote.txt b/Documentation/git-remote.txt
index 4feddc0..0cad37f 100644
--- a/Documentation/git-remote.txt
+++ b/Documentation/git-remote.txt
@@ -186,8 +186,8 @@
 
 'update'::
 
-Fetch updates for a named set of remotes in the repository as defined by
-remotes.<group>.  If a named group is not specified on the command line,
+Fetch updates for remotes or remote groups in the repository as defined by
+remotes.<group>.  If neither group nor remote is specified on the command line,
 the configuration parameter remotes.default will be used; if
 remotes.default is not defined, all remotes which do not have the
 configuration parameter remote.<name>.skipDefaultUpdate set to true will
@@ -203,7 +203,7 @@
 `remote.origin.fetch` configuration variables.  (See
 linkgit:git-config[1]).
 
-Examples
+EXAMPLES
 --------
 
 * Add a new remote, fetch, and check out a branch from it
diff --git a/Documentation/git-repack.txt b/Documentation/git-repack.txt
index ae750e9..d90e790 100644
--- a/Documentation/git-repack.txt
+++ b/Documentation/git-repack.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git repack' [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [--window=<n>] [--depth=<n>] [--threads=<n>]
+'git repack' [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [--window=<n>] [--depth=<n>] [--threads=<n>] [--keep-pack=<pack-name>]
 
 DESCRIPTION
 -----------
@@ -90,7 +90,9 @@
 	space. `--depth` limits the maximum delta depth; making it too deep
 	affects the performance on the unpacker side, because delta data needs
 	to be applied that many times to get to the necessary object.
-	The default value for --window is 10 and --depth is 50.
++
+The default value for --window is 10 and --depth is 50. The maximum
+depth is 4095.
 
 --threads=<n>::
 	This option is passed through to `git pack-objects`.
@@ -133,6 +135,13 @@
 	with `-b` or `repack.writeBitmaps`, as it ensures that the
 	bitmapped packfile has the necessary objects.
 
+--keep-pack=<pack-name>::
+	Exclude the given pack from repacking. This is the equivalent
+	of having `.keep` file on the pack. `<pack-name>` is the the
+	pack file name without leading directory (e.g. `pack-123.pack`).
+	The option could be specified multiple times to keep multiple
+	packs.
+
 --unpack-unreachable=<when>::
 	When loosening unreachable objects, do not bother loosening any
 	objects older than `<when>`. This can be used to optimize out
diff --git a/Documentation/git-replace.txt b/Documentation/git-replace.txt
index e5c57ae..246dc99 100644
--- a/Documentation/git-replace.txt
+++ b/Documentation/git-replace.txt
@@ -11,6 +11,7 @@
 'git replace' [-f] <object> <replacement>
 'git replace' [-f] --edit <object>
 'git replace' [-f] --graft <commit> [<parent>...]
+'git replace' [-f] --convert-graft-file
 'git replace' -d <object>...
 'git replace' [--format=<format>] [-l [<pattern>]]
 
@@ -87,9 +88,13 @@
 	content as <commit> except that its parents will be
 	[<parent>...] instead of <commit>'s parents. A replacement ref
 	is then created to replace <commit> with the newly created
-	commit. See contrib/convert-grafts-to-replace-refs.sh for an
-	example script based on this option that can convert grafts to
-	replace refs.
+	commit. Use `--convert-graft-file` to convert a
+	`$GIT_DIR/info/grafts` file and use replace refs instead.
+
+--convert-graft-file::
+	Creates graft commits for all entries in `$GIT_DIR/info/grafts`
+	and deletes that file upon success. The purpose is to help users
+	with transitioning off of the now-deprecated graft file.
 
 -l <pattern>::
 --list <pattern>::
diff --git a/Documentation/git-request-pull.txt b/Documentation/git-request-pull.txt
index c32cb0b..4d4392d 100644
--- a/Documentation/git-request-pull.txt
+++ b/Documentation/git-request-pull.txt
@@ -46,8 +46,8 @@
 its remote name.
 
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 Imagine that you built your work on your `master` branch on top of
 the `v1.0` release, and want it to be integrated to the project.
diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index 95326b8..e72d332 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git rev-parse' [ --option ] <args>...
+'git rev-parse' [<options>] <args>...
 
 DESCRIPTION
 -----------
@@ -360,7 +360,7 @@
 
 ------------
 OPTS_SPEC="\
-some-command [options] <args>...
+some-command [<options>] <args>...
 
 some-command does foo and bar!
 --
@@ -385,7 +385,7 @@
 usage text would be shown:
 
 ------------
-usage: some-command [options] <args>...
+usage: some-command [<options>] <args>...
 
     some-command does foo and bar!
 
diff --git a/Documentation/git-send-email.txt b/Documentation/git-send-email.txt
index 60cf96f..4f3efde 100644
--- a/Documentation/git-send-email.txt
+++ b/Documentation/git-send-email.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git send-email' [options] <file|directory|rev-list options>...
+'git send-email' [<options>] <file|directory|rev-list options>...
 'git send-email' --dump-aliases
 
 
@@ -458,8 +458,8 @@
 	one of 'always', 'never', 'cc', 'compose', or 'auto'. See `--confirm`
 	in the previous section for the meaning of these values.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 Use gmail as the smtp server
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 To use 'git send-email' to send your patches through the GMail SMTP server,
diff --git a/Documentation/git-send-pack.txt b/Documentation/git-send-pack.txt
index f51c649..44fd146 100644
--- a/Documentation/git-send-pack.txt
+++ b/Documentation/git-send-pack.txt
@@ -99,7 +99,7 @@
 	The remote refs to update.
 
 
-Specifying the Refs
+SPECIFYING THE REFS
 -------------------
 
 There are three ways to specify which refs to update on the
diff --git a/Documentation/git-shell.txt b/Documentation/git-shell.txt
index 54cf256..11361f3 100644
--- a/Documentation/git-shell.txt
+++ b/Documentation/git-shell.txt
@@ -62,8 +62,8 @@
 If a `no-interactive-login` command exists, then it is run and the
 interactive shell is aborted.
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 To disable interactive logins, displaying a greeting instead:
 
diff --git a/Documentation/git-shortlog.txt b/Documentation/git-shortlog.txt
index 5e35ea1..bc80905 100644
--- a/Documentation/git-shortlog.txt
+++ b/Documentation/git-shortlog.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 [verse]
-'git shortlog' [<options>] [<revision range>] [[\--] <path>...]
+'git shortlog' [<options>] [<revision range>] [[--] <path>...]
 git log --pretty=short | 'git shortlog' [<options>]
 
 DESCRIPTION
@@ -69,11 +69,11 @@
 	ways to spell <revision range>, see the "Specifying Ranges"
 	section of linkgit:gitrevisions[7].
 
-[\--] <path>...::
+[--] <path>...::
 	Consider only commits that are enough to explain how the files
 	that match the specified paths came to be.
 +
-Paths may need to be prefixed with "\-- " to separate them from
+Paths may need to be prefixed with `--` to separate them from
 options or the revision range, when confusion arises.
 
 MAPPING AUTHORS
diff --git a/Documentation/git-show-branch.txt b/Documentation/git-show-branch.txt
index 7818e0f..262db04 100644
--- a/Documentation/git-show-branch.txt
+++ b/Documentation/git-show-branch.txt
@@ -173,8 +173,8 @@
 The current branch is "master".
 
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 If you keep your primary branches immediately under
 `refs/heads`, and topic branches in subdirectories of
diff --git a/Documentation/git-show-ref.txt b/Documentation/git-show-ref.txt
index c0aa871..d28e615 100644
--- a/Documentation/git-show-ref.txt
+++ b/Documentation/git-show-ref.txt
@@ -120,8 +120,8 @@
 ...
 -----------------------------------------------------------------------------
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 To show all references called "master", whether tags or heads or anything
 else, and regardless of how deep in the reference naming hierarchy they are,
diff --git a/Documentation/git-show.txt b/Documentation/git-show.txt
index e73ef54..fcf528c 100644
--- a/Documentation/git-show.txt
+++ b/Documentation/git-show.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git show' [options] [<object>...]
+'git show' [<options>] [<object>...]
 
 DESCRIPTION
 -----------
@@ -77,7 +77,7 @@
 	Concatenates the contents of said Makefiles in the head
 	of the branch `master`.
 
-Discussion
+DISCUSSION
 ----------
 
 include::i18n.txt[]
diff --git a/Documentation/git-status.txt b/Documentation/git-status.txt
index c16e27e..c4467ff 100644
--- a/Documentation/git-status.txt
+++ b/Documentation/git-status.txt
@@ -135,6 +135,16 @@
 	Display or do not display detailed ahead/behind counts for the
 	branch relative to its upstream branch.  Defaults to true.
 
+--renames::
+--no-renames::
+	Turn on/off rename detection regardless of user configuration.
+	See also linkgit:git-diff[1] `--no-renames`.
+
+--find-renames[=<n>]::
+	Turn on rename detection, optionally setting the similarity
+	threshold.
+	See also linkgit:git-diff[1] `--find-renames`.
+
 <pathspec>...::
 	See the 'pathspec' entry in linkgit:gitglossary[7].
 
diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index 71c5618..4a5cc38 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -213,8 +213,8 @@
 	submodule URLs change upstream and you need to update your local
 	repositories accordingly.
 +
-"git submodule sync" synchronizes all submodules while
-"git submodule sync \-- A" synchronizes submodule "A" only.
+`git submodule sync` synchronizes all submodules while
+`git submodule sync -- A` synchronizes submodule "A" only.
 +
 If `--recursive` is specified, this command will recurse into the
 registered submodules, and sync any nested submodules within.
@@ -239,6 +239,13 @@
 --quiet::
 	Only print error messages.
 
+--progress::
+	This option is only valid for add and update commands.
+	Progress status is reported on the standard error stream
+	by default when it is attached to a terminal, unless -q
+	is specified. This flag forces progress status even if the
+	standard error stream is not directed to a terminal.
+
 --all::
 	This option is only valid for the deinit command. Unregister all
 	submodules in the working tree.
@@ -362,7 +369,15 @@
 	this option will be passed to the linkgit:git-clone[1] command.
 +
 *NOTE*: Do *not* use this option unless you have read the note
-for linkgit:git-clone[1]'s `--reference` and `--shared` options carefully.
+for linkgit:git-clone[1]'s `--reference`, `--shared`, and `--dissociate`
+options carefully.
+
+--dissociate::
+	This option is only valid for add and update commands.  These
+	commands sometimes need to clone a remote repository. In this case,
+	this option will be passed to the linkgit:git-clone[1] command.
++
+*NOTE*: see the NOTE for the `--reference` option.
 
 --recursive::
 	This option is only valid for foreach, update, status and sync commands.
diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
index d59379e..7ea24fc 100644
--- a/Documentation/git-svn.txt
+++ b/Documentation/git-svn.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 [verse]
-'git svn' <command> [options] [arguments]
+'git svn' <command> [<options>] [<arguments>]
 
 DESCRIPTION
 -----------
@@ -707,7 +707,7 @@
 config key: svn.useLogAuthor
 
 --add-author-from::
-	When committing to svn from Git (as part of 'commit-diff', 'set-tree' or 'dcommit'
+	When committing to svn from Git (as part of 'set-tree' or 'dcommit'
 	operations), if the existing log message doesn't already have a
 	`From:` or `Signed-off-by:` line, append a `From:` line based on the
 	Git commit's author string.  If you use this, then `--use-log-author`
diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index 1d17101..87c4288 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt
@@ -34,8 +34,8 @@
 If `-m <msg>` or `-F <file>` is given and `-a`, `-s`, and `-u <keyid>`
 are absent, `-a` is implied.
 
-Otherwise just a tag reference for the SHA-1 object name of the commit object is
-created (i.e. a lightweight tag).
+Otherwise, a tag reference that points directly at the given object
+(i.e., a lightweight tag) is created.
 
 A GnuPG signed tag object will be created when `-s` or `-u
 <keyid>` is used.  When `-u <keyid>` is not used, the
diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
index 3897a59..4e8e762 100644
--- a/Documentation/git-update-index.txt
+++ b/Documentation/git-update-index.txt
@@ -228,7 +228,7 @@
 	cleaner names.
 	The same applies to directories ending '/' and paths with '//'
 
-Using --refresh
+USING --REFRESH
 ---------------
 `--refresh` does not calculate a new sha1 file or bring the index
 up to date for mode/content changes. But what it *does* do is to
@@ -239,7 +239,7 @@
 For example, you'd want to do this after doing a 'git read-tree', to link
 up the stat index details with the proper files.
 
-Using --cacheinfo or --info-only
+USING --CACHEINFO OR --INFO-ONLY
 --------------------------------
 `--cacheinfo` is used to register a file that is not in the
 current working directory.  This is useful for minimum-checkout
@@ -261,7 +261,7 @@
 object database.
 
 
-Using --index-info
+USING --INDEX-INFO
 ------------------
 
 `--index-info` is a more powerful mechanism that lets you feed
@@ -317,7 +317,7 @@
 ------------
 
 
-Using ``assume unchanged'' bit
+USING ``ASSUME UNCHANGED'' BIT
 ------------------------------
 
 Many operations in Git depend on your filesystem to have an
@@ -350,7 +350,7 @@
 to mark them as "assume unchanged").
 
 
-Examples
+EXAMPLES
 --------
 To update and refresh only the files already checked out:
 
@@ -387,7 +387,7 @@
 <9> now it checks with lstat(2) and finds it has been changed.
 
 
-Skip-worktree bit
+SKIP-WORKTREE BIT
 -----------------
 
 Skip-worktree bit can be defined in one (long) sentence: When reading
@@ -407,7 +407,7 @@
 different from assume-unchanged bit's. Skip-worktree also takes
 precedence over assume-unchanged bit when both are set.
 
-Split index
+SPLIT INDEX
 -----------
 
 This mode is designed for repositories with very large indexes, and
@@ -432,7 +432,7 @@
 modification time is updated to the current time everytime a new split
 index based on the shared index file is either created or read from.
 
-Untracked cache
+UNTRACKED CACHE
 ---------------
 
 This cache is meant to speed up commands that involve determining
@@ -490,7 +490,7 @@
 status" run with `core.untrackedCache=false` to flush out the leftover
 bad data.
 
-File System Monitor
+FILE SYSTEM MONITOR
 -------------------
 
 This feature is intended to speed up git operations for repos that have
@@ -518,7 +518,7 @@
 a command reads the index. When `--[no-]fsmonitor` are used, the file
 system monitor is immediately added to or removed from the index.
 
-Configuration
+CONFIGURATION
 -------------
 
 The command honors `core.filemode` configuration variable.  If
diff --git a/Documentation/git-update-ref.txt b/Documentation/git-update-ref.txt
index 969bfab..bc8fdfd 100644
--- a/Documentation/git-update-ref.txt
+++ b/Documentation/git-update-ref.txt
@@ -120,7 +120,7 @@
 <ref> is updated or deleted atomically, a concurrent reader may
 still see a subset of the modifications.
 
-Logging Updates
+LOGGING UPDATES
 ---------------
 If config parameter "core.logAllRefUpdates" is true and the ref is one under
 "refs/heads/", "refs/remotes/", "refs/notes/", or the symbolic ref HEAD; or
diff --git a/Documentation/git-var.txt b/Documentation/git-var.txt
index 44ff954..6072f93 100644
--- a/Documentation/git-var.txt
+++ b/Documentation/git-var.txt
@@ -23,14 +23,14 @@
 	as well. (However, the configuration variables listing functionality
 	is deprecated in favor of `git config -l`.)
 
-EXAMPLE
+EXAMPLES
 --------
 	$ git var GIT_AUTHOR_IDENT
 	Eric W. Biederman <ebiederm@lnxi.com> 1121223278 -0600
 
 
 VARIABLES
-----------
+---------
 GIT_AUTHOR_IDENT::
     The author of a piece of code.
 
diff --git a/Documentation/git-web--browse.txt b/Documentation/git-web--browse.txt
index 2d6b09a..fd952a5 100644
--- a/Documentation/git-web--browse.txt
+++ b/Documentation/git-web--browse.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 [verse]
-'git web{litdd}browse' [OPTIONS] URL/FILE ...
+'git web{litdd}browse' [<options>] <url|file>...
 
 DESCRIPTION
 -----------
@@ -84,7 +84,7 @@
 as a custom command and will use a shell eval to run the command with
 the URLs passed as arguments.
 
-Note about konqueror
+NOTE ABOUT KONQUEROR
 --------------------
 
 When 'konqueror' is specified by a command-line option or a
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index 2755ca9..afc6576 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -14,7 +14,7 @@
 'git worktree lock' [--reason <string>] <worktree>
 'git worktree move' <worktree> <new-path>
 'git worktree prune' [-n] [-v] [--expire <expire>]
-'git worktree remove' [--force] <worktree>
+'git worktree remove' [-f] <worktree>
 'git worktree unlock' <worktree>
 
 DESCRIPTION
@@ -61,8 +61,13 @@
 ------------
 +
 If `<commit-ish>` is omitted and neither `-b` nor `-B` nor `--detach` used,
-then, as a convenience, a new branch based at HEAD is created automatically,
-as if `-b $(basename <path>)` was specified.
+then, as a convenience, the new worktree is associated with a branch
+(call it `<branch>`) named after `$(basename <path>)`.  If `<branch>`
+doesn't exist, a new branch based on HEAD is automatically created as
+if `-b <branch>` was given.  If `<branch>` does exist, it will be
+checked out in the new worktree, if it's not checked out anywhere
+else, otherwise the command will refuse to create the worktree (unless
+`--force` is used).
 
 list::
 
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 4767860..dba7f0c 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -11,7 +11,7 @@
 [verse]
 'git' [--version] [--help] [-C <path>] [-c <name>=<value>]
     [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
-    [-p|--paginate|--no-pager] [--no-replace-objects] [--bare]
+    [-p|--paginate|-P|--no-pager] [--no-replace-objects] [--bare]
     [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
     [--super-prefix=<path>]
     <command> [<args>]
@@ -103,6 +103,7 @@
 	configuration options (see the "Configuration Mechanism" section
 	below).
 
+-P::
 --no-pager::
 	Do not pipe Git output into a pager.
 
@@ -163,6 +164,16 @@
 	Do not perform optional operations that require locks. This is
 	equivalent to setting the `GIT_OPTIONAL_LOCKS` to `0`.
 
+--list-cmds=group[,group...]::
+	List commands by group. This is an internal/experimental
+	option and may change or be removed in the future. Supported
+	groups are: builtins, parseopt (builtin commands that use
+	parse-options), main (all commands in libexec directory),
+	others (all other commands in `$PATH` that have git- prefix),
+	list-<category> (see categories in command-list.txt),
+	nohelpers (exclude helper commands), alias and config
+	(retrieve command list from config variable completion.commands)
+
 GIT COMMANDS
 ------------
 
diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index 1094fe2..92010b0 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -3,7 +3,7 @@
 
 NAME
 ----
-gitattributes - defining attributes per path
+gitattributes - Defining attributes per path
 
 SYNOPSIS
 --------
@@ -279,6 +279,94 @@
   catch potential problems early, safety triggers.
 
 
+`working-tree-encoding`
+^^^^^^^^^^^^^^^^^^^^^^^
+
+Git recognizes files encoded in ASCII or one of its supersets (e.g.
+UTF-8, ISO-8859-1, ...) as text files. Files encoded in certain other
+encodings (e.g. UTF-16) are interpreted as binary and consequently
+built-in Git text processing tools (e.g. 'git diff') as well as most Git
+web front ends do not visualize the contents of these files by default.
+
+In these cases you can tell Git the encoding of a file in the working
+directory with the `working-tree-encoding` attribute. If a file with this
+attribute is added to Git, then Git reencodes the content from the
+specified encoding to UTF-8. Finally, Git stores the UTF-8 encoded
+content in its internal data structure (called "the index"). On checkout
+the content is reencoded back to the specified encoding.
+
+Please note that using the `working-tree-encoding` attribute may have a
+number of pitfalls:
+
+- Alternative Git implementations (e.g. JGit or libgit2) and older Git
+  versions (as of March 2018) do not support the `working-tree-encoding`
+  attribute. If you decide to use the `working-tree-encoding` attribute
+  in your repository, then it is strongly recommended to ensure that all
+  clients working with the repository support it.
+
+  For example, Microsoft Visual Studio resources files (`*.rc`) or
+  PowerShell script files (`*.ps1`) are sometimes encoded in UTF-16.
+  If you declare `*.ps1` as files as UTF-16 and you add `foo.ps1` with
+  a `working-tree-encoding` enabled Git client, then `foo.ps1` will be
+  stored as UTF-8 internally. A client without `working-tree-encoding`
+  support will checkout `foo.ps1` as UTF-8 encoded file. This will
+  typically cause trouble for the users of this file.
+
+  If a Git client, that does not support the `working-tree-encoding`
+  attribute, adds a new file `bar.ps1`, then `bar.ps1` will be
+  stored "as-is" internally (in this example probably as UTF-16).
+  A client with `working-tree-encoding` support will interpret the
+  internal contents as UTF-8 and try to convert it to UTF-16 on checkout.
+  That operation will fail and cause an error.
+
+- Reencoding content to non-UTF encodings can cause errors as the
+  conversion might not be UTF-8 round trip safe. If you suspect your
+  encoding to not be round trip safe, then add it to
+  `core.checkRoundtripEncoding` to make Git check the round trip
+  encoding (see linkgit:git-config[1]). SHIFT-JIS (Japanese character
+  set) is known to have round trip issues with UTF-8 and is checked by
+  default.
+
+- Reencoding content requires resources that might slow down certain
+  Git operations (e.g 'git checkout' or 'git add').
+
+Use the `working-tree-encoding` attribute only if you cannot store a file
+in UTF-8 encoding and if you want Git to be able to process the content
+as text.
+
+As an example, use the following attributes if your '*.ps1' files are
+UTF-16 encoded with byte order mark (BOM) and you want Git to perform
+automatic line ending conversion based on your platform.
+
+------------------------
+*.ps1		text working-tree-encoding=UTF-16
+------------------------
+
+Use the following attributes if your '*.ps1' files are UTF-16 little
+endian encoded without BOM and you want Git to use Windows line endings
+in the working directory. Please note, it is highly recommended to
+explicitly define the line endings with `eol` if the `working-tree-encoding`
+attribute is used to avoid ambiguity.
+
+------------------------
+*.ps1		text working-tree-encoding=UTF-16LE eol=CRLF
+------------------------
+
+You can get a list of all available encodings on your platform with the
+following command:
+
+------------------------
+iconv --list
+------------------------
+
+If you do not know the encoding of a file, then you can use the `file`
+command to guess the encoding:
+
+------------------------
+file foo.ps1
+------------------------
+
+
 `ident`
 ^^^^^^^
 
@@ -1141,8 +1229,8 @@
 ------------
 
 
-EXAMPLE
--------
+EXAMPLES
+--------
 
 If you have these three `gitattributes` file:
 
diff --git a/Documentation/gitcli.txt b/Documentation/gitcli.txt
index 9f13266..592e06d 100644
--- a/Documentation/gitcli.txt
+++ b/Documentation/gitcli.txt
@@ -110,8 +110,8 @@
 +
 ---------------------------------------------
 $ git describe -h
-usage: git describe [options] <commit-ish>*
-   or: git describe [options] --dirty
+usage: git describe [<options>] <commit-ish>*
+   or: git describe [<options>] --dirty
 
     --contains            find the tag that comes after the commit
     --debug               debug search strategy on stderr
diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt
index f877f7b..e3c283a 100644
--- a/Documentation/githooks.txt
+++ b/Documentation/githooks.txt
@@ -31,7 +31,7 @@
 arguments, and stdin. See the documentation for each hook below for
 details.
 
-'git init' may copy hooks to the new repository, depending on its
+`git init` may copy hooks to the new repository, depending on its
 configuration. See the "TEMPLATE DIRECTORY" section in
 linkgit:git-init[1] for details. When the rest of this document refers
 to "default hooks" it's talking about the default template shipped
@@ -45,9 +45,9 @@
 applypatch-msg
 ~~~~~~~~~~~~~~
 
-This hook is invoked by 'git am'.  It takes a single
+This hook is invoked by linkgit:git-am[1].  It takes a single
 parameter, the name of the file that holds the proposed commit
-log message.  Exiting with a non-zero status causes 'git am' to abort
+log message.  Exiting with a non-zero status causes `git am` to abort
 before applying the patch.
 
 The hook is allowed to edit the message file in place, and can
@@ -61,7 +61,7 @@
 pre-applypatch
 ~~~~~~~~~~~~~~
 
-This hook is invoked by 'git am'.  It takes no parameter, and is
+This hook is invoked by linkgit:git-am[1].  It takes no parameter, and is
 invoked after the patch is applied, but before a commit is made.
 
 If it exits with non-zero status, then the working tree will not be
@@ -76,33 +76,33 @@
 post-applypatch
 ~~~~~~~~~~~~~~~
 
-This hook is invoked by 'git am'.  It takes no parameter,
+This hook is invoked by linkgit:git-am[1].  It takes no parameter,
 and is invoked after the patch is applied and a commit is made.
 
 This hook is meant primarily for notification, and cannot affect
-the outcome of 'git am'.
+the outcome of `git am`.
 
 pre-commit
 ~~~~~~~~~~
 
-This hook is invoked by 'git commit', and can be bypassed
+This hook is invoked by linkgit:git-commit[1], and can be bypassed
 with the `--no-verify` option.  It takes no parameters, and is
 invoked before obtaining the proposed commit log message and
 making a commit.  Exiting with a non-zero status from this script
-causes the 'git commit' command to abort before creating a commit.
+causes the `git commit` command to abort before creating a commit.
 
 The default 'pre-commit' hook, when enabled, catches introduction
 of lines with trailing whitespaces and aborts the commit when
 such a line is found.
 
-All the 'git commit' hooks are invoked with the environment
+All the `git commit` hooks are invoked with the environment
 variable `GIT_EDITOR=:` if the command will not bring up an editor
 to modify the commit message.
 
 prepare-commit-msg
 ~~~~~~~~~~~~~~~~~~
 
-This hook is invoked by 'git commit' right after preparing the
+This hook is invoked by linkgit:git-commit[1] right after preparing the
 default log message, and before the editor is started.
 
 It takes one to three parameters.  The first is the name of the file
@@ -114,7 +114,7 @@
 (if a `.git/SQUASH_MSG` file exists); or `commit`, followed by
 a commit SHA-1 (if a `-c`, `-C` or `--amend` option was given).
 
-If the exit status is non-zero, 'git commit' will abort.
+If the exit status is non-zero, `git commit` will abort.
 
 The purpose of the hook is to edit the message file in place, and
 it is not suppressed by the `--no-verify` option.  A non-zero exit
@@ -127,7 +127,7 @@
 commit-msg
 ~~~~~~~~~~
 
-This hook is invoked by 'git commit' and 'git merge', and can be
+This hook is invoked by linkgit:git-commit[1] and linkgit:git-merge[1], and can be
 bypassed with the `--no-verify` option.  It takes a single parameter,
 the name of the file that holds the proposed commit log message.
 Exiting with a non-zero status causes the command to abort.
@@ -143,16 +143,16 @@
 post-commit
 ~~~~~~~~~~~
 
-This hook is invoked by 'git commit'. It takes no parameters, and is
+This hook is invoked by linkgit:git-commit[1]. It takes no parameters, and is
 invoked after a commit is made.
 
 This hook is meant primarily for notification, and cannot affect
-the outcome of 'git commit'.
+the outcome of `git commit`.
 
 pre-rebase
 ~~~~~~~~~~
 
-This hook is called by 'git rebase' and can be used to prevent a
+This hook is called by linkgit:git-rebase[1] and can be used to prevent a
 branch from getting rebased.  The hook may be called with one or
 two parameters.  The first parameter is the upstream from which
 the series was forked.  The second parameter is the branch being
@@ -161,17 +161,17 @@
 post-checkout
 ~~~~~~~~~~~~~
 
-This hook is invoked when a 'git checkout' is run after having updated the
+This hook is invoked when a linkgit:git-checkout[1] is run after having updated the
 worktree.  The hook is given three parameters: the ref of the previous HEAD,
 the ref of the new HEAD (which may or may not have changed), and a flag
 indicating whether the checkout was a branch checkout (changing branches,
 flag=1) or a file checkout (retrieving a file from the index, flag=0).
-This hook cannot affect the outcome of 'git checkout'.
+This hook cannot affect the outcome of `git checkout`.
 
-It is also run after 'git clone', unless the --no-checkout (-n) option is
+It is also run after linkgit:git-clone[1], unless the `--no-checkout` (`-n`) option is
 used. The first parameter given to the hook is the null-ref, the second the
-ref of the new HEAD and the flag is always 1. Likewise for 'git worktree add'
-unless --no-checkout is used.
+ref of the new HEAD and the flag is always 1. Likewise for `git worktree add`
+unless `--no-checkout` is used.
 
 This hook can be used to perform repository validity checks, auto-display
 differences from the previous HEAD if different, or set working dir metadata
@@ -180,10 +180,10 @@
 post-merge
 ~~~~~~~~~~
 
-This hook is invoked by 'git merge', which happens when a 'git pull'
+This hook is invoked by linkgit:git-merge[1], which happens when a `git pull`
 is done on a local repository.  The hook takes a single parameter, a status
 flag specifying whether or not the merge being done was a squash merge.
-This hook cannot affect the outcome of 'git merge' and is not executed,
+This hook cannot affect the outcome of `git merge` and is not executed,
 if the merge failed due to conflicts.
 
 This hook can be used in conjunction with a corresponding pre-commit hook to
@@ -194,10 +194,10 @@
 pre-push
 ~~~~~~~~
 
-This hook is called by 'git push' and can be used to prevent a push from taking
-place.  The hook is called with two parameters which provide the name and
-location of the destination remote, if a named remote is not being used both
-values will be the same.
+This hook is called by linkgit:git-push[1] and can be used to prevent
+a push from taking place.  The hook is called with two parameters
+which provide the name and location of the destination remote, if a
+named remote is not being used both values will be the same.
 
 Information about what is to be pushed is provided on the hook's standard
 input with lines of the form:
@@ -216,7 +216,7 @@
 than a name which could be expanded (such as `HEAD~`, or a SHA-1) it will be
 supplied as it was originally given.
 
-If this hook exits with a non-zero status, 'git push' will abort without
+If this hook exits with a non-zero status, `git push` will abort without
 pushing anything.  Information about why the push is rejected may be sent
 to the user by writing to standard error.
 
@@ -224,8 +224,8 @@
 pre-receive
 ~~~~~~~~~~~
 
-This hook is invoked by 'git-receive-pack' when it reacts to
-'git push' and updates reference(s) in its repository.
+This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
+`git push` and updates reference(s) in its repository.
 Just before starting to update refs on the remote repository, the
 pre-receive hook is invoked.  Its exit status determines the success
 or failure of the update.
@@ -246,7 +246,7 @@
 still be prevented by the <<update,'update'>> hook.
 
 Both standard output and standard error output are forwarded to
-'git send-pack' on the other end, so you can simply `echo` messages
+`git send-pack` on the other end, so you can simply `echo` messages
 for the user.
 
 The number of push options given on the command line of
@@ -265,8 +265,8 @@
 update
 ~~~~~~
 
-This hook is invoked by 'git-receive-pack' when it reacts to
-'git push' and updates reference(s) in its repository.
+This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
+`git push` and updates reference(s) in its repository.
 Just before updating the ref on the remote repository, the update hook
 is invoked.  Its exit status determines the success or failure of
 the ref update.
@@ -279,7 +279,7 @@
  - and the new object name to be stored in the ref.
 
 A zero exit from the update hook allows the ref to be updated.
-Exiting with a non-zero status prevents 'git-receive-pack'
+Exiting with a non-zero status prevents `git receive-pack`
 from updating that ref.
 
 This hook can be used to prevent 'forced' update on certain refs by
@@ -299,7 +299,7 @@
 shell to restrict the user's access to only git commands.
 
 Both standard output and standard error output are forwarded to
-'git send-pack' on the other end, so you can simply `echo` messages
+`git send-pack` on the other end, so you can simply `echo` messages
 for the user.
 
 The default 'update' hook, when enabled--and with
@@ -310,8 +310,8 @@
 post-receive
 ~~~~~~~~~~~~
 
-This hook is invoked by 'git-receive-pack' when it reacts to
-'git push' and updates reference(s) in its repository.
+This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
+`git push` and updates reference(s) in its repository.
 It executes on the remote repository once after all the refs have
 been updated.
 
@@ -320,7 +320,7 @@
 <<pre-receive,'pre-receive'>>
 hook does on its standard input.
 
-This hook does not affect the outcome of 'git-receive-pack', as it
+This hook does not affect the outcome of `git receive-pack`, as it
 is called after the real work is done.
 
 This supersedes the <<post-update,'post-update'>> hook in that it gets
@@ -328,7 +328,7 @@
 names.
 
 Both standard output and standard error output are forwarded to
-'git send-pack' on the other end, so you can simply `echo` messages
+`git send-pack` on the other end, so you can simply `echo` messages
 for the user.
 
 The default 'post-receive' hook is empty, but there is
@@ -349,8 +349,8 @@
 post-update
 ~~~~~~~~~~~
 
-This hook is invoked by 'git-receive-pack' when it reacts to
-'git push' and updates reference(s) in its repository.
+This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
+`git push` and updates reference(s) in its repository.
 It executes on the remote repository once after all the refs have
 been updated.
 
@@ -358,7 +358,7 @@
 name of ref that was actually updated.
 
 This hook is meant primarily for notification, and cannot affect
-the outcome of 'git-receive-pack'.
+the outcome of `git receive-pack`.
 
 The 'post-update' hook can tell what are the heads that were pushed,
 but it does not know what their original and updated values are,
@@ -368,20 +368,20 @@
 them.
 
 When enabled, the default 'post-update' hook runs
-'git update-server-info' to keep the information used by dumb
+`git update-server-info` to keep the information used by dumb
 transports (e.g., HTTP) up to date.  If you are publishing
 a Git repository that is accessible via HTTP, you should
 probably enable this hook.
 
 Both standard output and standard error output are forwarded to
-'git send-pack' on the other end, so you can simply `echo` messages
+`git send-pack` on the other end, so you can simply `echo` messages
 for the user.
 
 push-to-checkout
 ~~~~~~~~~~~~~~~~
 
-This hook is invoked by 'git-receive-pack' when it reacts to
-'git push' and updates reference(s) in its repository, and when
+This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
+`git push` and updates reference(s) in its repository, and when
 the push tries to update the branch that is currently checked out
 and the `receive.denyCurrentBranch` configuration variable is set to
 `updateInstead`.  Such a push by default is refused if the working
@@ -400,8 +400,8 @@
 exit with a zero status.
 
 For example, the hook can simply run `git read-tree -u -m HEAD "$1"`
-in order to emulate 'git fetch' that is run in the reverse direction
-with `git push`, as the two-tree form of `read-tree -u -m` is
+in order to emulate `git fetch` that is run in the reverse direction
+with `git push`, as the two-tree form of `git read-tree -u -m` is
 essentially the same as `git checkout` that switches branches while
 keeping the local changes in the working tree that do not interfere
 with the difference between the branches.
@@ -410,15 +410,16 @@
 pre-auto-gc
 ~~~~~~~~~~~
 
-This hook is invoked by 'git gc --auto'. It takes no parameter, and
-exiting with non-zero status from this script causes the 'git gc --auto'
-to abort.
+This hook is invoked by `git gc --auto` (see linkgit:git-gc[1]). It
+takes no parameter, and exiting with non-zero status from this script
+causes the `git gc --auto` to abort.
 
 post-rewrite
 ~~~~~~~~~~~~
 
-This hook is invoked by commands that rewrite commits (`git commit
---amend`, 'git-rebase'; currently 'git-filter-branch' does 'not' call
+This hook is invoked by commands that rewrite commits
+(linkgit:git-commit[1] when called with `--amend` and
+linkgit:git-rebase[1]; currently `git filter-branch` does 'not' call
 it!).  Its first argument denotes the command it was invoked by:
 currently one of `amend` or `rebase`.  Further command-dependent
 arguments may be passed in the future.
@@ -450,16 +451,16 @@
 sendemail-validate
 ~~~~~~~~~~~~~~~~~~
 
-This hook is invoked by 'git send-email'.  It takes a single parameter,
+This hook is invoked by linkgit:git-send-email[1].  It takes a single parameter,
 the name of the file that holds the e-mail to be sent.  Exiting with a
-non-zero status causes 'git send-email' to abort before sending any
+non-zero status causes `git send-email` to abort before sending any
 e-mails.
 
 fsmonitor-watchman
 ~~~~~~~~~~~~~~~~~~
 
-This hook is invoked when the configuration option core.fsmonitor is
-set to .git/hooks/fsmonitor-watchman.  It takes two arguments, a version
+This hook is invoked when the configuration option `core.fsmonitor` is
+set to `.git/hooks/fsmonitor-watchman`.  It takes two arguments, a version
 (currently 1) and the time in elapsed nanoseconds since midnight,
 January 1, 1970.
 
@@ -478,7 +479,7 @@
 given.
 
 An optimized way to tell git "all files have changed" is to return
-the filename '/'.
+the filename `/`.
 
 The exit status determines whether git will use the data from the
 hook to limit its search.  On error, it will fall back to verifying
diff --git a/Documentation/gitk.txt b/Documentation/gitk.txt
index ca96c28..244cd01 100644
--- a/Documentation/gitk.txt
+++ b/Documentation/gitk.txt
@@ -8,7 +8,7 @@
 SYNOPSIS
 --------
 [verse]
-'gitk' [<options>] [<revision range>] [\--] [<path>...]
+'gitk' [<options>] [<revision range>] [--] [<path>...]
 
 DESCRIPTION
 -----------
diff --git a/Documentation/gitmodules.txt b/Documentation/gitmodules.txt
index db5d47e..4d63def 100644
--- a/Documentation/gitmodules.txt
+++ b/Documentation/gitmodules.txt
@@ -3,7 +3,7 @@
 
 NAME
 ----
-gitmodules - defining submodule properties
+gitmodules - Defining submodule properties
 
 SYNOPSIS
 --------
diff --git a/Documentation/gitremote-helpers.txt b/Documentation/gitremote-helpers.txt
index 4b8c93e..9d1459a 100644
--- a/Documentation/gitremote-helpers.txt
+++ b/Documentation/gitremote-helpers.txt
@@ -102,6 +102,14 @@
 +
 Supported commands: 'connect'.
 
+'stateless-connect'::
+	Experimental; for internal use only.
+	Can attempt to connect to a remote server for communication
+	using git's wire-protocol version 2.  See the documentation
+	for the stateless-connect command for more information.
++
+Supported commands: 'stateless-connect'.
+
 'push'::
 	Can discover remote refs and push local commits and the
 	history leading up to them to new or existing remote refs.
@@ -136,6 +144,14 @@
 +
 Supported commands: 'connect'.
 
+'stateless-connect'::
+	Experimental; for internal use only.
+	Can attempt to connect to a remote server for communication
+	using git's wire-protocol version 2.  See the documentation
+	for the stateless-connect command for more information.
++
+Supported commands: 'stateless-connect'.
+
 'fetch'::
 	Can discover remote refs and transfer objects reachable from
 	them to the local object store.
@@ -375,6 +391,22 @@
 +
 Supported if the helper has the "connect" capability.
 
+'stateless-connect' <service>::
+	Experimental; for internal use only.
+	Connects to the given remote service for communication using
+	git's wire-protocol version 2.  Valid replies to this command
+	are empty line (connection established), 'fallback' (no smart
+	transport support, fall back to dumb transports) and just
+	exiting with error message printed (can't connect, don't bother
+	trying to fall back).  After line feed terminating the positive
+	(empty) response, the output of the service starts.  Messages
+	(both request and response) must consist of zero or more
+	PKT-LINEs, terminating in a flush packet. The client must not
+	expect the server to store any state in between request-response
+	pairs.  After the connection ends, the remote helper exits.
++
+Supported if the helper has the "stateless-connect" capability.
+
 If a fatal error occurs, the program writes the error message to
 stderr and exits. The caller should expect that a suitable error
 message has been printed if the child closes the connection without
diff --git a/Documentation/gitrevisions.txt b/Documentation/gitrevisions.txt
index 27dec5b..1f6ccea 100644
--- a/Documentation/gitrevisions.txt
+++ b/Documentation/gitrevisions.txt
@@ -3,7 +3,7 @@
 
 NAME
 ----
-gitrevisions - specifying revisions and ranges for Git
+gitrevisions - Specifying revisions and ranges for Git
 
 SYNOPSIS
 --------
diff --git a/Documentation/glossary-content.txt b/Documentation/glossary-content.txt
index 6b8888d..6c2d23d 100644
--- a/Documentation/glossary-content.txt
+++ b/Documentation/glossary-content.txt
@@ -463,7 +463,7 @@
 [[def_push]]push::
 	Pushing a <<def_branch,branch>> means to get the branch's
 	<<def_head_ref,head ref>> from a remote <<def_repository,repository>>,
-	find out if it is a direct ancestor to the branch's local
+	find out if it is an ancestor to the branch's local
 	head ref, and in that case, putting all
 	objects, which are <<def_reachable,reachable>> from the local
 	head ref, and which are missing from the remote
diff --git a/Documentation/merge-config.txt b/Documentation/merge-config.txt
index 12b6bbf..662c271 100644
--- a/Documentation/merge-config.txt
+++ b/Documentation/merge-config.txt
@@ -35,7 +35,13 @@
 merge.renameLimit::
 	The number of files to consider when performing rename detection
 	during a merge; if not specified, defaults to the value of
-	diff.renameLimit.
+	diff.renameLimit. This setting has no effect if rename detection
+	is turned off.
+
+merge.renames::
+	Whether and how Git detects renames.  If set to "false",
+	rename detection is disabled. If set to "true", basic rename
+	detection is enabled.  Defaults to the value of diff.renames.
 
 merge.renormalize::
 	Tell Git that canonical representation of files in the
diff --git a/Documentation/merge-strategies.txt b/Documentation/merge-strategies.txt
index 4a58aad..aa66cbe 100644
--- a/Documentation/merge-strategies.txt
+++ b/Documentation/merge-strategies.txt
@@ -23,8 +23,9 @@
 	causing mismerges by tests done on actual merge commits
 	taken from Linux 2.6 kernel development history.
 	Additionally this can detect and handle merges involving
-	renames.  This is the default merge strategy when
-	pulling or merging one branch.
+	renames, but currently cannot make use of detected
+	copies.  This is the default merge strategy when pulling
+	or merging one branch.
 +
 The 'recursive' strategy can take the following options:
 
@@ -84,12 +85,14 @@
 	`merge.renormalize` configuration variable.
 
 no-renames;;
-	Turn off rename detection.
+	Turn off rename detection. This overrides the `merge.renames`
+	configuration variable.
 	See also linkgit:git-diff[1] `--no-renames`.
 
 find-renames[=<n>];;
 	Turn on rename detection, optionally setting the similarity
-	threshold.  This is the default.
+	threshold.  This is the default. This overrides the
+	'merge.renames' configuration variable.
 	See also linkgit:git-diff[1] `--find-renames`.
 
 rename-threshold=<n>;;
diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
index dfcc49c..7d1bd44 100644
--- a/Documentation/revisions.txt
+++ b/Documentation/revisions.txt
@@ -7,6 +7,10 @@
 ones listed near the end of this list name trees and
 blobs contained in a commit.
 
+NOTE: This document shows the "raw" syntax as seen by git. The shell
+and other UIs might require additional quoting to protect special
+characters and to avoid word splitting.
+
 '<sha1>', e.g. 'dae86e1950b1277e545cee180551750029cfe735', 'dae86e'::
   The full SHA-1 object name (40-byte hexadecimal string), or
   a leading substring that is unique within the repository.
@@ -186,6 +190,8 @@
   is matched. ':/!-foo' performs a negative match, while ':/!!foo' matches a
   literal '!' character, followed by 'foo'. Any other sequence beginning with
   ':/!' is reserved for now.
+  Depending on the given text, the shell's word splitting rules might
+  require additional quoting.
 
 '<rev>:<path>', e.g. 'HEAD:README', ':README', 'master:./README'::
   A suffix ':' followed by a path names the blob or tree
@@ -345,6 +351,7 @@
 with each step in the notation's expansion and selection carefully
 spelt out:
 
+....
    Args   Expanded arguments    Selected commits
    D                            G H D
    D F                          G H I J D F
@@ -367,3 +374,4 @@
 	  = B ^B^1 ^B^2 ^B^3
 	  = B ^D ^E ^F          B
    F^! D  = F ^I ^J D           G H D F
+....
diff --git a/Documentation/technical/api-config.txt b/Documentation/technical/api-config.txt
index 9a778b0..fa39ac9 100644
--- a/Documentation/technical/api-config.txt
+++ b/Documentation/technical/api-config.txt
@@ -47,21 +47,23 @@
 repo-specific one; by overwriting, the higher-priority repo-specific
 value is left at the end).
 
-The `git_config_with_options` function lets the caller examine config
+The `config_with_options` function lets the caller examine config
 while adjusting some of the default behavior of `git_config`. It should
 almost never be used by "regular" Git code that is looking up
 configuration variables. It is intended for advanced callers like
 `git-config`, which are intentionally tweaking the normal config-lookup
 process. It takes two extra parameters:
 
-`filename`::
-If this parameter is non-NULL, it specifies the name of a file to
-parse for configuration, rather than looking in the usual files. Regular
-`git_config` defaults to `NULL`.
+`config_source`::
+If this parameter is non-NULL, it specifies the source to parse for
+configuration, rather than looking in the usual files. See `struct
+git_config_source` in `config.h` for details. Regular `git_config` defaults
+to `NULL`.
 
-`respect_includes`::
-Specify whether include directives should be followed in parsed files.
-Regular `git_config` defaults to `1`.
+`opts`::
+Specify options to adjust the behavior of parsing config files. See `struct
+config_options` in `config.h` for details. As an example: regular `git_config`
+sets `opts.respect_includes` to `1` by default.
 
 Reading Specific Files
 ----------------------
diff --git a/Documentation/technical/api-oid-array.txt b/Documentation/technical/api-oid-array.txt
index b0c11f8..9febfb1 100644
--- a/Documentation/technical/api-oid-array.txt
+++ b/Documentation/technical/api-oid-array.txt
@@ -35,13 +35,18 @@
 	Free all memory associated with the array and return it to the
 	initial, empty state.
 
+`oid_array_for_each`::
+	Iterate over each element of the list, executing the callback
+	function for each one. Does not sort the list, so any custom
+	hash order is retained. If the callback returns a non-zero
+	value, the iteration ends immediately and the callback's
+	return is propagated; otherwise, 0 is returned.
+
 `oid_array_for_each_unique`::
-	Efficiently iterate over each unique element of the list,
-	executing the callback function for each one. If the array is
-	not sorted, this function has the side effect of sorting it. If
-	the callback returns a non-zero value, the iteration ends
-	immediately and the callback's return is propagated; otherwise,
-	0 is returned.
+	Iterate over each unique element of the list in sorted order,
+	but otherwise behave like `oid_array_for_each`. If the array
+	is not sorted, this function has the side effect of sorting
+	it.
 
 Examples
 --------
diff --git a/Documentation/technical/api-submodule-config.txt b/Documentation/technical/api-submodule-config.txt
index ee907c4..fb06089 100644
--- a/Documentation/technical/api-submodule-config.txt
+++ b/Documentation/technical/api-submodule-config.txt
@@ -38,7 +38,7 @@
 Functions
 ---------
 
-`void submodule_free()`::
+`void submodule_free(struct repository *r)`::
 
 	Use these to free the internally cached values.
 
diff --git a/Documentation/technical/commit-graph-format.txt b/Documentation/technical/commit-graph-format.txt
new file mode 100644
index 0000000..ad6af81
--- /dev/null
+++ b/Documentation/technical/commit-graph-format.txt
@@ -0,0 +1,97 @@
+Git commit graph format
+=======================
+
+The Git commit graph stores a list of commit OIDs and some associated
+metadata, including:
+
+- The generation number of the commit. Commits with no parents have
+  generation number 1; commits with parents have generation number
+  one more than the maximum generation number of its parents. We
+  reserve zero as special, and can be used to mark a generation
+  number invalid or as "not computed".
+
+- The root tree OID.
+
+- The commit date.
+
+- The parents of the commit, stored using positional references within
+  the graph file.
+
+These positional references are stored as unsigned 32-bit integers
+corresponding to the array position withing the list of commit OIDs. We
+use the most-significant bit for special purposes, so we can store at most
+(1 << 31) - 1 (around 2 billion) commits.
+
+== Commit graph files have the following format:
+
+In order to allow extensions that add extra data to the graph, we organize
+the body into "chunks" and provide a binary lookup table at the beginning
+of the body. The header includes certain values, such as number of chunks
+and hash type.
+
+All 4-byte numbers are in network order.
+
+HEADER:
+
+  4-byte signature:
+      The signature is: {'C', 'G', 'P', 'H'}
+
+  1-byte version number:
+      Currently, the only valid version is 1.
+
+  1-byte Hash Version (1 = SHA-1)
+      We infer the hash length (H) from this value.
+
+  1-byte number (C) of "chunks"
+
+  1-byte (reserved for later use)
+     Current clients should ignore this value.
+
+CHUNK LOOKUP:
+
+  (C + 1) * 12 bytes listing the table of contents for the chunks:
+      First 4 bytes describe the chunk id. Value 0 is a terminating label.
+      Other 8 bytes provide the byte-offset in current file for chunk to
+      start. (Chunks are ordered contiguously in the file, so you can infer
+      the length using the next chunk position if necessary.) Each chunk
+      ID appears at most once.
+
+  The remaining data in the body is described one chunk at a time, and
+  these chunks may be given in any order. Chunks are required unless
+  otherwise specified.
+
+CHUNK DATA:
+
+  OID Fanout (ID: {'O', 'I', 'D', 'F'}) (256 * 4 bytes)
+      The ith entry, F[i], stores the number of OIDs with first
+      byte at most i. Thus F[255] stores the total
+      number of commits (N).
+
+  OID Lookup (ID: {'O', 'I', 'D', 'L'}) (N * H bytes)
+      The OIDs for all commits in the graph, sorted in ascending order.
+
+  Commit Data (ID: {'C', 'G', 'E', 'T' }) (N * (H + 16) bytes)
+    * The first H bytes are for the OID of the root tree.
+    * The next 8 bytes are for the positions of the first two parents
+      of the ith commit. Stores value 0xffffffff if no parent in that
+      position. If there are more than two parents, the second value
+      has its most-significant bit on and the other bits store an array
+      position into the Large Edge List chunk.
+    * The next 8 bytes store the generation number of the commit and
+      the commit time in seconds since EPOCH. The generation number
+      uses the higher 30 bits of the first 4 bytes, while the commit
+      time uses the 32 bits of the second 4 bytes, along with the lowest
+      2 bits of the lowest byte, storing the 33rd and 34th bit of the
+      commit time.
+
+  Large Edge List (ID: {'E', 'D', 'G', 'E'}) [Optional]
+      This list of 4-byte values store the second through nth parents for
+      all octopus merges. The second parent value in the commit data stores
+      an array position within this list along with the most-significant bit
+      on. Starting at that array position, iterate through this list of commit
+      positions for the parents until reaching a value with the most-significant
+      bit on. The other bits correspond to the position of the last parent.
+
+TRAILER:
+
+	H-byte HASH-checksum of all of the above.
diff --git a/Documentation/technical/commit-graph.txt b/Documentation/technical/commit-graph.txt
new file mode 100644
index 0000000..0550c6d
--- /dev/null
+++ b/Documentation/technical/commit-graph.txt
@@ -0,0 +1,163 @@
+Git Commit Graph Design Notes
+=============================
+
+Git walks the commit graph for many reasons, including:
+
+1. Listing and filtering commit history.
+2. Computing merge bases.
+
+These operations can become slow as the commit count grows. The merge
+base calculation shows up in many user-facing commands, such as 'merge-base'
+or 'status' and can take minutes to compute depending on history shape.
+
+There are two main costs here:
+
+1. Decompressing and parsing commits.
+2. Walking the entire graph to satisfy topological order constraints.
+
+The commit graph file is a supplemental data structure that accelerates
+commit graph walks. If a user downgrades or disables the 'core.commitGraph'
+config setting, then the existing ODB is sufficient. The file is stored
+as "commit-graph" either in the .git/objects/info directory or in the info
+directory of an alternate.
+
+The commit graph file stores the commit graph structure along with some
+extra metadata to speed up graph walks. By listing commit OIDs in lexi-
+cographic order, we can identify an integer position for each commit and
+refer to the parents of a commit using those integer positions. We use
+binary search to find initial commits and then use the integer positions
+for fast lookups during the walk.
+
+A consumer may load the following info for a commit from the graph:
+
+1. The commit OID.
+2. The list of parents, along with their integer position.
+3. The commit date.
+4. The root tree OID.
+5. The generation number (see definition below).
+
+Values 1-4 satisfy the requirements of parse_commit_gently().
+
+Define the "generation number" of a commit recursively as follows:
+
+ * A commit with no parents (a root commit) has generation number one.
+
+ * A commit with at least one parent has generation number one more than
+   the largest generation number among its parents.
+
+Equivalently, the generation number of a commit A is one more than the
+length of a longest path from A to a root commit. The recursive definition
+is easier to use for computation and observing the following property:
+
+    If A and B are commits with generation numbers N and M, respectively,
+    and N <= M, then A cannot reach B. That is, we know without searching
+    that B is not an ancestor of A because it is further from a root commit
+    than A.
+
+    Conversely, when checking if A is an ancestor of B, then we only need
+    to walk commits until all commits on the walk boundary have generation
+    number at most N. If we walk commits using a priority queue seeded by
+    generation numbers, then we always expand the boundary commit with highest
+    generation number and can easily detect the stopping condition.
+
+This property can be used to significantly reduce the time it takes to
+walk commits and determine topological relationships. Without generation
+numbers, the general heuristic is the following:
+
+    If A and B are commits with commit time X and Y, respectively, and
+    X < Y, then A _probably_ cannot reach B.
+
+This heuristic is currently used whenever the computation is allowed to
+violate topological relationships due to clock skew (such as "git log"
+with default order), but is not used when the topological order is
+required (such as merge base calculations, "git log --graph").
+
+In practice, we expect some commits to be created recently and not stored
+in the commit graph. We can treat these commits as having "infinite"
+generation number and walk until reaching commits with known generation
+number.
+
+Design Details
+--------------
+
+- The commit graph file is stored in a file named 'commit-graph' in the
+  .git/objects/info directory. This could be stored in the info directory
+  of an alternate.
+
+- The core.commitGraph config setting must be on to consume graph files.
+
+- The file format includes parameters for the object ID hash function,
+  so a future change of hash algorithm does not require a change in format.
+
+Future Work
+-----------
+
+- The commit graph feature currently does not honor commit grafts. This can
+  be remedied by duplicating or refactoring the current graft logic.
+
+- The 'commit-graph' subcommand does not have a "verify" mode that is
+  necessary for integration with fsck.
+
+- The file format includes room for precomputed generation numbers. These
+  are not currently computed, so all generation numbers will be marked as
+  0 (or "uncomputed"). A later patch will include this calculation.
+
+- After computing and storing generation numbers, we must make graph
+  walks aware of generation numbers to gain the performance benefits they
+  enable. This will mostly be accomplished by swapping a commit-date-ordered
+  priority queue with one ordered by generation number. The following
+  operations are important candidates:
+
+    - paint_down_to_common()
+    - 'log --topo-order'
+
+- Currently, parse_commit_gently() requires filling in the root tree
+  object for a commit. This passes through lookup_tree() and consequently
+  lookup_object(). Also, it calls lookup_commit() when loading the parents.
+  These method calls check the ODB for object existence, even if the
+  consumer does not need the content. For example, we do not need the
+  tree contents when computing merge bases. Now that commit parsing is
+  removed from the computation time, these lookup operations are the
+  slowest operations keeping graph walks from being fast. Consider
+  loading these objects without verifying their existence in the ODB and
+  only loading them fully when consumers need them. Consider a method
+  such as "ensure_tree_loaded(commit)" that fully loads a tree before
+  using commit->tree.
+
+- The current design uses the 'commit-graph' subcommand to generate the graph.
+  When this feature stabilizes enough to recommend to most users, we should
+  add automatic graph writes to common operations that create many commits.
+  For example, one could compute a graph on 'clone', 'fetch', or 'repack'
+  commands.
+
+- A server could provide a commit graph file as part of the network protocol
+  to avoid extra calculations by clients. This feature is only of benefit if
+  the user is willing to trust the file, because verifying the file is correct
+  is as hard as computing it from scratch.
+
+Related Links
+-------------
+[0] https://bugs.chromium.org/p/git/issues/detail?id=8
+    Chromium work item for: Serialized Commit Graph
+
+[1] https://public-inbox.org/git/20110713070517.GC18566@sigill.intra.peff.net/
+    An abandoned patch that introduced generation numbers.
+
+[2] https://public-inbox.org/git/20170908033403.q7e6dj7benasrjes@sigill.intra.peff.net/
+    Discussion about generation numbers on commits and how they interact
+    with fsck.
+
+[3] https://public-inbox.org/git/20170908034739.4op3w4f2ma5s65ku@sigill.intra.peff.net/
+    More discussion about generation numbers and not storing them inside
+    commit objects. A valuable quote:
+
+    "I think we should be moving more in the direction of keeping
+     repo-local caches for optimizations. Reachability bitmaps have been
+     a big performance win. I think we should be doing the same with our
+     properties of commits. Not just generation numbers, but making it
+     cheap to access the graph structure without zlib-inflating whole
+     commit objects (i.e., packv4 or something like the "metapacks" I
+     proposed a few years ago)."
+
+[4] https://public-inbox.org/git/20180108154822.54829-1-git@jeffhostetler.com/T/#u
+    A patch to remove the ahead-behind calculation from 'status'.
diff --git a/Documentation/technical/pack-format.txt b/Documentation/technical/pack-format.txt
index 8e5bf60..70a99fd 100644
--- a/Documentation/technical/pack-format.txt
+++ b/Documentation/technical/pack-format.txt
@@ -36,6 +36,98 @@
 
   - The trailer records 20-byte SHA-1 checksum of all of the above.
 
+=== Object types
+
+Valid object types are:
+
+- OBJ_COMMIT (1)
+- OBJ_TREE (2)
+- OBJ_BLOB (3)
+- OBJ_TAG (4)
+- OBJ_OFS_DELTA (6)
+- OBJ_REF_DELTA (7)
+
+Type 5 is reserved for future expansion. Type 0 is invalid.
+
+=== Deltified representation
+
+Conceptually there are only four object types: commit, tree, tag and
+blob. However to save space, an object could be stored as a "delta" of
+another "base" object. These representations are assigned new types
+ofs-delta and ref-delta, which is only valid in a pack file.
+
+Both ofs-delta and ref-delta store the "delta" to be applied to
+another object (called 'base object') to reconstruct the object. The
+difference between them is, ref-delta directly encodes 20-byte base
+object name. If the base object is in the same pack, ofs-delta encodes
+the offset of the base object in the pack instead.
+
+The base object could also be deltified if it's in the same pack.
+Ref-delta can also refer to an object outside the pack (i.e. the
+so-called "thin pack"). When stored on disk however, the pack should
+be self contained to avoid cyclic dependency.
+
+The delta data is a sequence of instructions to reconstruct an object
+from the base object. If the base object is deltified, it must be
+converted to canonical form first. Each instruction appends more and
+more data to the target object until it's complete. There are two
+supported instructions so far: one for copy a byte range from the
+source object and one for inserting new data embedded in the
+instruction itself.
+
+Each instruction has variable length. Instruction type is determined
+by the seventh bit of the first octet. The following diagrams follow
+the convention in RFC 1951 (Deflate compressed data format).
+
+==== Instruction to copy from base object
+
+  +----------+---------+---------+---------+---------+-------+-------+-------+
+  | 1xxxxxxx | offset1 | offset2 | offset3 | offset4 | size1 | size2 | size3 |
+  +----------+---------+---------+---------+---------+-------+-------+-------+
+
+This is the instruction format to copy a byte range from the source
+object. It encodes the offset to copy from and the number of bytes to
+copy. Offset and size are in little-endian order.
+
+All offset and size bytes are optional. This is to reduce the
+instruction size when encoding small offsets or sizes. The first seven
+bits in the first octet determines which of the next seven octets is
+present. If bit zero is set, offset1 is present. If bit one is set
+offset2 is present and so on.
+
+Note that a more compact instruction does not change offset and size
+encoding. For example, if only offset2 is omitted like below, offset3
+still contains bits 16-23. It does not become offset2 and contains
+bits 8-15 even if it's right next to offset1.
+
+  +----------+---------+---------+
+  | 10000101 | offset1 | offset3 |
+  +----------+---------+---------+
+
+In its most compact form, this instruction only takes up one byte
+(0x80) with both offset and size omitted, which will have default
+values zero. There is another exception: size zero is automatically
+converted to 0x10000.
+
+==== Instruction to add new data
+
+  +----------+============+
+  | 0xxxxxxx |    data    |
+  +----------+============+
+
+This is the instruction to construct target object without the base
+object. The following data is appended to the target object. The first
+seven bits of the first octet determines the size of data in
+bytes. The size must be non-zero.
+
+==== Reserved instruction
+
+  +----------+============
+  | 00000000 |
+  +----------+============
+
+This is the instruction reserved for future expansion.
+
 == Original (version 1) pack-*.idx files have the following format:
 
   - The header consists of 256 4-byte network byte order
diff --git a/Documentation/technical/protocol-v2.txt b/Documentation/technical/protocol-v2.txt
new file mode 100644
index 0000000..49bda76
--- /dev/null
+++ b/Documentation/technical/protocol-v2.txt
@@ -0,0 +1,414 @@
+ Git Wire Protocol, Version 2
+==============================
+
+This document presents a specification for a version 2 of Git's wire
+protocol.  Protocol v2 will improve upon v1 in the following ways:
+
+  * Instead of multiple service names, multiple commands will be
+    supported by a single service
+  * Easily extendable as capabilities are moved into their own section
+    of the protocol, no longer being hidden behind a NUL byte and
+    limited by the size of a pkt-line
+  * Separate out other information hidden behind NUL bytes (e.g. agent
+    string as a capability and symrefs can be requested using 'ls-refs')
+  * Reference advertisement will be omitted unless explicitly requested
+  * ls-refs command to explicitly request some refs
+  * Designed with http and stateless-rpc in mind.  With clear flush
+    semantics the http remote helper can simply act as a proxy
+
+In protocol v2 communication is command oriented.  When first contacting a
+server a list of capabilities will advertised.  Some of these capabilities
+will be commands which a client can request be executed.  Once a command
+has completed, a client can reuse the connection and request that other
+commands be executed.
+
+ Packet-Line Framing
+---------------------
+
+All communication is done using packet-line framing, just as in v1.  See
+`Documentation/technical/pack-protocol.txt` and
+`Documentation/technical/protocol-common.txt` for more information.
+
+In protocol v2 these special packets will have the following semantics:
+
+  * '0000' Flush Packet (flush-pkt) - indicates the end of a message
+  * '0001' Delimiter Packet (delim-pkt) - separates sections of a message
+
+ Initial Client Request
+------------------------
+
+In general a client can request to speak protocol v2 by sending
+`version=2` through the respective side-channel for the transport being
+used which inevitably sets `GIT_PROTOCOL`.  More information can be
+found in `pack-protocol.txt` and `http-protocol.txt`.  In all cases the
+response from the server is the capability advertisement.
+
+ Git Transport
+~~~~~~~~~~~~~~~
+
+When using the git:// transport, you can request to use protocol v2 by
+sending "version=2" as an extra parameter:
+
+   003egit-upload-pack /project.git\0host=myserver.com\0\0version=2\0
+
+ SSH and File Transport
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+When using either the ssh:// or file:// transport, the GIT_PROTOCOL
+environment variable must be set explicitly to include "version=2".
+
+ HTTP Transport
+~~~~~~~~~~~~~~~~
+
+When using the http:// or https:// transport a client makes a "smart"
+info/refs request as described in `http-protocol.txt` and requests that
+v2 be used by supplying "version=2" in the `Git-Protocol` header.
+
+   C: Git-Protocol: version=2
+   C:
+   C: GET $GIT_URL/info/refs?service=git-upload-pack HTTP/1.0
+
+A v2 server would reply:
+
+   S: 200 OK
+   S: <Some headers>
+   S: ...
+   S:
+   S: 000eversion 2\n
+   S: <capability-advertisement>
+
+Subsequent requests are then made directly to the service
+`$GIT_URL/git-upload-pack`. (This works the same for git-receive-pack).
+
+ Capability Advertisement
+--------------------------
+
+A server which decides to communicate (based on a request from a client)
+using protocol version 2, notifies the client by sending a version string
+in its initial response followed by an advertisement of its capabilities.
+Each capability is a key with an optional value.  Clients must ignore all
+unknown keys.  Semantics of unknown values are left to the definition of
+each key.  Some capabilities will describe commands which can be requested
+to be executed by the client.
+
+    capability-advertisement = protocol-version
+			       capability-list
+			       flush-pkt
+
+    protocol-version = PKT-LINE("version 2" LF)
+    capability-list = *capability
+    capability = PKT-LINE(key[=value] LF)
+
+    key = 1*(ALPHA | DIGIT | "-_")
+    value = 1*(ALPHA | DIGIT | " -_.,?\/{}[]()<>!@#$%^&*+=:;")
+
+ Command Request
+-----------------
+
+After receiving the capability advertisement, a client can then issue a
+request to select the command it wants with any particular capabilities
+or arguments.  There is then an optional section where the client can
+provide any command specific parameters or queries.  Only a single
+command can be requested at a time.
+
+    request = empty-request | command-request
+    empty-request = flush-pkt
+    command-request = command
+		      capability-list
+		      [command-args]
+		      flush-pkt
+    command = PKT-LINE("command=" key LF)
+    command-args = delim-pkt
+		   *command-specific-arg
+
+    command-specific-args are packet line framed arguments defined by
+    each individual command.
+
+The server will then check to ensure that the client's request is
+comprised of a valid command as well as valid capabilities which were
+advertised.  If the request is valid the server will then execute the
+command.  A server MUST wait till it has received the client's entire
+request before issuing a response.  The format of the response is
+determined by the command being executed, but in all cases a flush-pkt
+indicates the end of the response.
+
+When a command has finished, and the client has received the entire
+response from the server, a client can either request that another
+command be executed or can terminate the connection.  A client may
+optionally send an empty request consisting of just a flush-pkt to
+indicate that no more requests will be made.
+
+ Capabilities
+--------------
+
+There are two different types of capabilities: normal capabilities,
+which can be used to to convey information or alter the behavior of a
+request, and commands, which are the core actions that a client wants to
+perform (fetch, push, etc).
+
+Protocol version 2 is stateless by default.  This means that all commands
+must only last a single round and be stateless from the perspective of the
+server side, unless the client has requested a capability indicating that
+state should be maintained by the server.  Clients MUST NOT require state
+management on the server side in order to function correctly.  This
+permits simple round-robin load-balancing on the server side, without
+needing to worry about state management.
+
+ agent
+~~~~~~~
+
+The server can advertise the `agent` capability with a value `X` (in the
+form `agent=X`) to notify the client that the server is running version
+`X`.  The client may optionally send its own agent string by including
+the `agent` capability with a value `Y` (in the form `agent=Y`) in its
+request to the server (but it MUST NOT do so if the server did not
+advertise the agent capability). The `X` and `Y` strings may contain any
+printable ASCII characters except space (i.e., the byte range 32 < x <
+127), and are typically of the form "package/version" (e.g.,
+"git/1.8.3.1"). The agent strings are purely informative for statistics
+and debugging purposes, and MUST NOT be used to programmatically assume
+the presence or absence of particular features.
+
+ ls-refs
+~~~~~~~~~
+
+`ls-refs` is the command used to request a reference advertisement in v2.
+Unlike the current reference advertisement, ls-refs takes in arguments
+which can be used to limit the refs sent from the server.
+
+Additional features not supported in the base command will be advertised
+as the value of the command in the capability advertisement in the form
+of a space separated list of features: "<command>=<feature 1> <feature 2>"
+
+ls-refs takes in the following arguments:
+
+    symrefs
+	In addition to the object pointed by it, show the underlying ref
+	pointed by it when showing a symbolic ref.
+    peel
+	Show peeled tags.
+    ref-prefix <prefix>
+	When specified, only references having a prefix matching one of
+	the provided prefixes are displayed.
+
+The output of ls-refs is as follows:
+
+    output = *ref
+	     flush-pkt
+    ref = PKT-LINE(obj-id SP refname *(SP ref-attribute) LF)
+    ref-attribute = (symref | peeled)
+    symref = "symref-target:" symref-target
+    peeled = "peeled:" obj-id
+
+ fetch
+~~~~~~~
+
+`fetch` is the command used to fetch a packfile in v2.  It can be looked
+at as a modified version of the v1 fetch where the ref-advertisement is
+stripped out (since the `ls-refs` command fills that role) and the
+message format is tweaked to eliminate redundancies and permit easy
+addition of future extensions.
+
+Additional features not supported in the base command will be advertised
+as the value of the command in the capability advertisement in the form
+of a space separated list of features: "<command>=<feature 1> <feature 2>"
+
+A `fetch` request can take the following arguments:
+
+    want <oid>
+	Indicates to the server an object which the client wants to
+	retrieve.  Wants can be anything and are not limited to
+	advertised objects.
+
+    have <oid>
+	Indicates to the server an object which the client has locally.
+	This allows the server to make a packfile which only contains
+	the objects that the client needs. Multiple 'have' lines can be
+	supplied.
+
+    done
+	Indicates to the server that negotiation should terminate (or
+	not even begin if performing a clone) and that the server should
+	use the information supplied in the request to construct the
+	packfile.
+
+    thin-pack
+	Request that a thin pack be sent, which is a pack with deltas
+	which reference base objects not contained within the pack (but
+	are known to exist at the receiving end). This can reduce the
+	network traffic significantly, but it requires the receiving end
+	to know how to "thicken" these packs by adding the missing bases
+	to the pack.
+
+    no-progress
+	Request that progress information that would normally be sent on
+	side-band channel 2, during the packfile transfer, should not be
+	sent.  However, the side-band channel 3 is still used for error
+	responses.
+
+    include-tag
+	Request that annotated tags should be sent if the objects they
+	point to are being sent.
+
+    ofs-delta
+	Indicate that the client understands PACKv2 with delta referring
+	to its base by position in pack rather than by an oid.  That is,
+	they can read OBJ_OFS_DELTA (ake type 6) in a packfile.
+
+If the 'shallow' feature is advertised the following arguments can be
+included in the clients request as well as the potential addition of the
+'shallow-info' section in the server's response as explained below.
+
+    shallow <oid>
+	A client must notify the server of all commits for which it only
+	has shallow copies (meaning that it doesn't have the parents of
+	a commit) by supplying a 'shallow <oid>' line for each such
+	object so that the server is aware of the limitations of the
+	client's history.  This is so that the server is aware that the
+	client may not have all objects reachable from such commits.
+
+    deepen <depth>
+	Requests that the fetch/clone should be shallow having a commit
+	depth of <depth> relative to the remote side.
+
+    deepen-relative
+	Requests that the semantics of the "deepen" command be changed
+	to indicate that the depth requested is relative to the client's
+	current shallow boundary, instead of relative to the requested
+	commits.
+
+    deepen-since <timestamp>
+	Requests that the shallow clone/fetch should be cut at a
+	specific time, instead of depth.  Internally it's equivalent to
+	doing "git rev-list --max-age=<timestamp>". Cannot be used with
+	"deepen".
+
+    deepen-not <rev>
+	Requests that the shallow clone/fetch should be cut at a
+	specific revision specified by '<rev>', instead of a depth.
+	Internally it's equivalent of doing "git rev-list --not <rev>".
+	Cannot be used with "deepen", but can be used with
+	"deepen-since".
+
+If the 'filter' feature is advertised, the following argument can be
+included in the client's request:
+
+    filter <filter-spec>
+	Request that various objects from the packfile be omitted
+	using one of several filtering techniques. These are intended
+	for use with partial clone and partial fetch operations. See
+	`rev-list` for possible "filter-spec" values.
+
+The response of `fetch` is broken into a number of sections separated by
+delimiter packets (0001), with each section beginning with its section
+header.
+
+    output = *section
+    section = (acknowledgments | shallow-info | packfile)
+	      (flush-pkt | delim-pkt)
+
+    acknowledgments = PKT-LINE("acknowledgments" LF)
+		      (nak | *ack)
+		      (ready)
+    ready = PKT-LINE("ready" LF)
+    nak = PKT-LINE("NAK" LF)
+    ack = PKT-LINE("ACK" SP obj-id LF)
+
+    shallow-info = PKT-LINE("shallow-info" LF)
+		   *PKT-LINE((shallow | unshallow) LF)
+    shallow = "shallow" SP obj-id
+    unshallow = "unshallow" SP obj-id
+
+    packfile = PKT-LINE("packfile" LF)
+	       *PKT-LINE(%x01-03 *%x00-ff)
+
+    acknowledgments section
+	* If the client determines that it is finished with negotiations
+	  by sending a "done" line, the acknowledgments sections MUST be
+	  omitted from the server's response.
+
+	* Always begins with the section header "acknowledgments"
+
+	* The server will respond with "NAK" if none of the object ids sent
+	  as have lines were common.
+
+	* The server will respond with "ACK obj-id" for all of the
+	  object ids sent as have lines which are common.
+
+	* A response cannot have both "ACK" lines as well as a "NAK"
+	  line.
+
+	* The server will respond with a "ready" line indicating that
+	  the server has found an acceptable common base and is ready to
+	  make and send a packfile (which will be found in the packfile
+	  section of the same response)
+
+	* If the server has found a suitable cut point and has decided
+	  to send a "ready" line, then the server can decide to (as an
+	  optimization) omit any "ACK" lines it would have sent during
+	  its response.  This is because the server will have already
+	  determined the objects it plans to send to the client and no
+	  further negotiation is needed.
+
+    shallow-info section
+	* If the client has requested a shallow fetch/clone, a shallow
+	  client requests a fetch or the server is shallow then the
+	  server's response may include a shallow-info section.  The
+	  shallow-info section will be included if (due to one of the
+	  above conditions) the server needs to inform the client of any
+	  shallow boundaries or adjustments to the clients already
+	  existing shallow boundaries.
+
+	* Always begins with the section header "shallow-info"
+
+	* If a positive depth is requested, the server will compute the
+	  set of commits which are no deeper than the desired depth.
+
+	* The server sends a "shallow obj-id" line for each commit whose
+	  parents will not be sent in the following packfile.
+
+	* The server sends an "unshallow obj-id" line for each commit
+	  which the client has indicated is shallow, but is no longer
+	  shallow as a result of the fetch (due to its parents being
+	  sent in the following packfile).
+
+	* The server MUST NOT send any "unshallow" lines for anything
+	  which the client has not indicated was shallow as a part of
+	  its request.
+
+	* This section is only included if a packfile section is also
+	  included in the response.
+
+    packfile section
+	* This section is only included if the client has sent 'want'
+	  lines in its request and either requested that no more
+	  negotiation be done by sending 'done' or if the server has
+	  decided it has found a sufficient cut point to produce a
+	  packfile.
+
+	* Always begins with the section header "packfile"
+
+	* The transmission of the packfile begins immediately after the
+	  section header
+
+	* The data transfer of the packfile is always multiplexed, using
+	  the same semantics of the 'side-band-64k' capability from
+	  protocol version 1.  This means that each packet, during the
+	  packfile data stream, is made up of a leading 4-byte pkt-line
+	  length (typical of the pkt-line format), followed by a 1-byte
+	  stream code, followed by the actual data.
+
+	  The stream code can be one of:
+		1 - pack data
+		2 - progress messages
+		3 - fatal error message just before stream aborts
+
+ server-option
+~~~~~~~~~~~~~~~
+
+If advertised, indicates that any number of server specific options can be
+included in a request.  This is done by sending each option as a
+"server-option=<option>" capability line in the capability-list section of
+a request.
+
+The provided options must not contain a NUL or LF character.
diff --git a/Documentation/technical/shallow.txt b/Documentation/technical/shallow.txt
index 5183b15..01dedfe 100644
--- a/Documentation/technical/shallow.txt
+++ b/Documentation/technical/shallow.txt
@@ -8,20 +8,22 @@
 these commits have no parents.
 *********************************************************
 
-The basic idea is to write the SHA-1s of shallow commits into
-$GIT_DIR/shallow, and handle its contents like the contents
-of $GIT_DIR/info/grafts (with the difference that shallow
-cannot contain parent information).
-
-This information is stored in a new file instead of grafts, or
-even the config, since the user should not touch that file
-at all (even throughout development of the shallow clone, it
-was never manually edited!).
+$GIT_DIR/shallow lists commit object names and tells Git to
+pretend as if they are root commits (e.g. "git log" traversal
+stops after showing them; "git fsck" does not complain saying
+the commits listed on their "parent" lines do not exist).
 
 Each line contains exactly one SHA-1. When read, a commit_graft
 will be constructed, which has nr_parent < 0 to make it easier
 to discern from user provided grafts.
 
+Note that the shallow feature could not be changed easily to
+use replace refs: a commit containing a `mergetag` is not allowed
+to be replaced, not even by a root commit. Such a commit can be
+made shallow, though. Also, having a `shallow` file explicitly
+listing all the commits made shallow makes it a *lot* easier to
+do shallow-specific things such as to deepen the history.
+
 Since fsck-objects relies on the library to read the objects,
 it honours shallow commits automatically.
 
diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index 12ff59c..bdd758e 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 GVF=GIT-VERSION-FILE
-DEF_VER=v2.17.GIT
+DEF_VER=v2.18.0-rc0
 
 LF='
 '
diff --git a/Makefile b/Makefile
index 50da82b..1d27f36 100644
--- a/Makefile
+++ b/Makefile
@@ -441,6 +441,49 @@
 #
 # When cross-compiling, define HOST_CPU as the canonical name of the CPU on
 # which the built Git will run (for instance "x86_64").
+#
+# Define RUNTIME_PREFIX to configure Git to resolve its ancillary tooling and
+# support files relative to the location of the runtime binary, rather than
+# hard-coding them into the binary. Git installations built with RUNTIME_PREFIX
+# can be moved to arbitrary filesystem locations. RUNTIME_PREFIX also causes
+# Perl scripts to use a modified entry point header allowing them to resolve
+# support files at runtime.
+#
+# When using RUNTIME_PREFIX, define HAVE_BSD_KERN_PROC_SYSCTL if your platform
+# supports the KERN_PROC BSD sysctl function.
+#
+# When using RUNTIME_PREFIX, define PROCFS_EXECUTABLE_PATH if your platform
+# mounts a "procfs" filesystem capable of resolving the path of the current
+# executable. If defined, this must be the canonical path for the "procfs"
+# current executable path.
+#
+# When using RUNTIME_PREFIX, define HAVE_NS_GET_EXECUTABLE_PATH if your platform
+# supports calling _NSGetExecutablePath to retrieve the path of the running
+# executable.
+#
+# When using RUNTIME_PREFIX, define HAVE_WPGMPTR if your platform offers
+# the global variable _wpgmptr containing the absolute path of the current
+# executable (this is the case on Windows).
+#
+# Define DEVELOPER to enable more compiler warnings. Compiler version
+# and family are auto detected, but could be overridden by defining
+# COMPILER_FEATURES (see config.mak.dev)
+#
+# When DEVELOPER is set, DEVOPTS can be used to control compiler
+# options.  This variable contains keywords separated by
+# whitespace. The following keywords are are recognized:
+#
+#    no-error:
+#
+#        suppresses the -Werror that implicitly comes with
+#        DEVELOPER=1. Useful for getting the full set of errors
+#        without immediately dying, or for logging them.
+#
+#    extra-all:
+#
+#        The DEVELOPER mode enables -Wextra with a few exceptions. By
+#        setting this flag the exceptions are removed, and all of
+#        -Wextra is used.
 
 GIT-VERSION-FILE: FORCE
 	@$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -449,15 +492,6 @@
 # CFLAGS and LDFLAGS are for the users to override from the command line.
 
 CFLAGS = -g -O2 -Wall
-DEVELOPER_CFLAGS = -Werror \
-	-Wdeclaration-after-statement \
-	-Wno-format-zero-length \
-	-Wold-style-definition \
-	-Woverflow \
-	-Wpointer-arith \
-	-Wstrict-prototypes \
-	-Wunused \
-	-Wvla
 LDFLAGS =
 ALL_CFLAGS = $(CPPFLAGS) $(CFLAGS)
 ALL_LDFLAGS = $(LDFLAGS)
@@ -478,6 +512,8 @@
 #   mandir
 #   infodir
 #   htmldir
+#   localedir
+#   perllibdir
 # This can help installing the suite in a relocatable way.
 
 prefix = $(HOME)
@@ -502,7 +538,9 @@
 mandir_relative = $(patsubst $(prefix)/%,%,$(mandir))
 infodir_relative = $(patsubst $(prefix)/%,%,$(infodir))
 gitexecdir_relative = $(patsubst $(prefix)/%,%,$(gitexecdir))
+localedir_relative = $(patsubst $(prefix)/%,%,$(localedir))
 htmldir_relative = $(patsubst $(prefix)/%,%,$(htmldir))
+perllibdir_relative = $(patsubst $(prefix)/%,%,$(perllibdir))
 
 export prefix bindir sharedir sysconfdir gitwebdir perllibdir localedir
 
@@ -652,7 +690,6 @@
 PROGRAM_OBJS += sh-i18n--envsubst.o
 PROGRAM_OBJS += shell.o
 PROGRAM_OBJS += show-index.o
-PROGRAM_OBJS += upload-pack.o
 PROGRAM_OBJS += remote-testsvn.o
 
 # Binary suffix, set to .exe for Windows builds
@@ -701,6 +738,7 @@
 TEST_PROGRAMS_NEED_X += test-fake-ssh
 TEST_PROGRAMS_NEED_X += test-line-buffer
 TEST_PROGRAMS_NEED_X += test-parse-options
+TEST_PROGRAMS_NEED_X += test-pkt-line
 TEST_PROGRAMS_NEED_X += test-svn-fe
 TEST_PROGRAMS_NEED_X += test-tool
 
@@ -757,7 +795,7 @@
 XDIFF_LIB = xdiff/lib.a
 VCSSVN_LIB = vcs-svn/lib.a
 
-GENERATED_H += common-cmds.h
+GENERATED_H += command-list.h
 
 LIB_H = $(shell $(FIND) . \
 	-name .git -prune -o \
@@ -789,6 +827,7 @@
 LIB_OBJS += column.o
 LIB_OBJS += combine-diff.o
 LIB_OBJS += commit.o
+LIB_OBJS += commit-graph.o
 LIB_OBJS += compat/obstack.o
 LIB_OBJS += compat/terminal.o
 LIB_OBJS += config.o
@@ -842,6 +881,7 @@
 LIB_OBJS += ll-merge.o
 LIB_OBJS += lockfile.o
 LIB_OBJS += log-tree.o
+LIB_OBJS += ls-refs.o
 LIB_OBJS += mailinfo.o
 LIB_OBJS += mailmap.o
 LIB_OBJS += match-trees.o
@@ -888,6 +928,7 @@
 LIB_OBJS += refs/iterator.o
 LIB_OBJS += refs/packed-backend.o
 LIB_OBJS += refs/ref-cache.o
+LIB_OBJS += refspec.o
 LIB_OBJS += ref-filter.o
 LIB_OBJS += remote.o
 LIB_OBJS += replace-object.o
@@ -898,6 +939,7 @@
 LIB_OBJS += run-command.o
 LIB_OBJS += send-pack.o
 LIB_OBJS += sequencer.o
+LIB_OBJS += serve.o
 LIB_OBJS += server-info.o
 LIB_OBJS += setup.o
 LIB_OBJS += sha1-array.o
@@ -926,6 +968,7 @@
 LIB_OBJS += tree.o
 LIB_OBJS += tree-walk.o
 LIB_OBJS += unpack-trees.o
+LIB_OBJS += upload-pack.o
 LIB_OBJS += url.o
 LIB_OBJS += urlmatch.o
 LIB_OBJS += usage.o
@@ -965,6 +1008,7 @@
 BUILTIN_OBJS += builtin/column.o
 BUILTIN_OBJS += builtin/commit-tree.o
 BUILTIN_OBJS += builtin/commit.o
+BUILTIN_OBJS += builtin/commit-graph.o
 BUILTIN_OBJS += builtin/config.o
 BUILTIN_OBJS += builtin/count-objects.o
 BUILTIN_OBJS += builtin/credential.o
@@ -1030,6 +1074,7 @@
 BUILTIN_OBJS += builtin/revert.o
 BUILTIN_OBJS += builtin/rm.o
 BUILTIN_OBJS += builtin/send-pack.o
+BUILTIN_OBJS += builtin/serve.o
 BUILTIN_OBJS += builtin/shortlog.o
 BUILTIN_OBJS += builtin/show-branch.o
 BUILTIN_OBJS += builtin/show-ref.o
@@ -1043,6 +1088,7 @@
 BUILTIN_OBJS += builtin/update-ref.o
 BUILTIN_OBJS += builtin/update-server-info.o
 BUILTIN_OBJS += builtin/upload-archive.o
+BUILTIN_OBJS += builtin/upload-pack.o
 BUILTIN_OBJS += builtin/var.o
 BUILTIN_OBJS += builtin/verify-commit.o
 BUILTIN_OBJS += builtin/verify-pack.o
@@ -1064,7 +1110,7 @@
 -include config.mak
 
 ifdef DEVELOPER
-CFLAGS += $(DEVELOPER_CFLAGS)
+include config.mak.dev
 endif
 
 comma := ,
@@ -1665,10 +1711,27 @@
 	BASIC_CFLAGS += -DHAVE_BSD_SYSCTL
 endif
 
+ifdef HAVE_BSD_KERN_PROC_SYSCTL
+	BASIC_CFLAGS += -DHAVE_BSD_KERN_PROC_SYSCTL
+endif
+
 ifdef HAVE_GETDELIM
 	BASIC_CFLAGS += -DHAVE_GETDELIM
 endif
 
+ifneq ($(PROCFS_EXECUTABLE_PATH),)
+	procfs_executable_path_SQ = $(subst ','\'',$(PROCFS_EXECUTABLE_PATH))
+	BASIC_CFLAGS += '-DPROCFS_EXECUTABLE_PATH="$(procfs_executable_path_SQ)"'
+endif
+
+ifdef HAVE_NS_GET_EXECUTABLE_PATH
+	BASIC_CFLAGS += -DHAVE_NS_GET_EXECUTABLE_PATH
+endif
+
+ifdef HAVE_WPGMPTR
+	BASIC_CFLAGS += -DHAVE_WPGMPTR
+endif
+
 ifeq ($(TCLTK_PATH),)
 NO_TCLTK = NoThanks
 endif
@@ -1753,11 +1816,13 @@
 infodir_relative_SQ = $(subst ','\'',$(infodir_relative))
 perllibdir_SQ = $(subst ','\'',$(perllibdir))
 localedir_SQ = $(subst ','\'',$(localedir))
+localedir_relative_SQ = $(subst ','\'',$(localedir_relative))
 gitexecdir_SQ = $(subst ','\'',$(gitexecdir))
 gitexecdir_relative_SQ = $(subst ','\'',$(gitexecdir_relative))
 template_dir_SQ = $(subst ','\'',$(template_dir))
 htmldir_relative_SQ = $(subst ','\'',$(htmldir_relative))
 prefix_SQ = $(subst ','\'',$(prefix))
+perllibdir_relative_SQ = $(subst ','\'',$(perllibdir_relative))
 gitwebdir_SQ = $(subst ','\'',$(gitwebdir))
 
 SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))
@@ -1768,6 +1833,31 @@
 DIFF_SQ = $(subst ','\'',$(DIFF))
 PERLLIB_EXTRA_SQ = $(subst ','\'',$(PERLLIB_EXTRA))
 
+# RUNTIME_PREFIX's resolution logic requires resource paths to be expressed
+# relative to each other and share an installation path.
+#
+# This is a dependency in:
+# - Git's binary RUNTIME_PREFIX logic in (see "exec_cmd.c").
+# - The runtime prefix Perl header (see
+#   "perl/header_templates/runtime_prefix.template.pl").
+ifdef RUNTIME_PREFIX
+
+ifneq ($(filter /%,$(firstword $(gitexecdir_relative))),)
+$(error RUNTIME_PREFIX requires a relative gitexecdir, not: $(gitexecdir))
+endif
+
+ifneq ($(filter /%,$(firstword $(localedir_relative))),)
+$(error RUNTIME_PREFIX requires a relative localedir, not: $(localedir))
+endif
+
+ifndef NO_PERL
+ifneq ($(filter /%,$(firstword $(perllibdir_relative))),)
+$(error RUNTIME_PREFIX requires a relative perllibdir, not: $(perllibdir))
+endif
+endif
+
+endif
+
 # We must filter out any object files from $(GITLIBS),
 # as it is typically used like:
 #
@@ -1916,9 +2006,9 @@
 	$(QUIET_LINK)$(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) \
 		$(filter %.o,$^) $(LIBS)
 
-help.sp help.s help.o: common-cmds.h
+help.sp help.s help.o: command-list.h
 
-builtin/help.sp builtin/help.s builtin/help.o: common-cmds.h GIT-PREFIX
+builtin/help.sp builtin/help.s builtin/help.o: command-list.h GIT-PREFIX
 builtin/help.sp builtin/help.s builtin/help.o: EXTRA_CPPFLAGS = \
 	'-DGIT_HTML_PATH="$(htmldir_relative_SQ)"' \
 	'-DGIT_MAN_PATH="$(mandir_relative_SQ)"' \
@@ -1937,9 +2027,9 @@
 	ln -s $< $@ 2>/dev/null || \
 	cp $< $@
 
-common-cmds.h: generate-cmdlist.sh command-list.txt
+command-list.h: generate-cmdlist.sh command-list.txt
 
-common-cmds.h: $(wildcard Documentation/git-*.txt)
+command-list.h: $(wildcard Documentation/git*.txt)
 	$(QUIET_GEN)$(SHELL_PATH) ./generate-cmdlist.sh command-list.txt >$@+ && mv $@+ $@
 
 SCRIPT_DEFINES = $(SHELL_PATH_SQ):$(DIFF_SQ):$(GIT_VERSION):\
@@ -1988,27 +2078,44 @@
 # This makes sure we depend on the NO_PERL setting itself.
 $(SCRIPT_PERL_GEN): GIT-BUILD-OPTIONS
 
-ifndef NO_PERL
-$(SCRIPT_PERL_GEN):
+# Used for substitution in Perl modules. Disabled when using RUNTIME_PREFIX
+# since the locale directory is injected.
+perl_localedir_SQ = $(localedir_SQ)
 
+ifndef NO_PERL
+PERL_HEADER_TEMPLATE = perl/header_templates/fixed_prefix.template.pl
 PERL_DEFINES = $(PERL_PATH_SQ):$(PERLLIB_EXTRA_SQ):$(perllibdir_SQ)
-$(SCRIPT_PERL_GEN): % : %.perl GIT-PERL-DEFINES GIT-VERSION-FILE
+
+PERL_DEFINES := $(PERL_PATH_SQ) $(PERLLIB_EXTRA_SQ) $(perllibdir_SQ)
+PERL_DEFINES += $(RUNTIME_PREFIX)
+
+# Support Perl runtime prefix. In this mode, a different header is installed
+# into Perl scripts.
+ifdef RUNTIME_PREFIX
+
+PERL_HEADER_TEMPLATE = perl/header_templates/runtime_prefix.template.pl
+
+# Don't export a fixed $(localedir) path; it will be resolved by the Perl header
+# at runtime.
+perl_localedir_SQ =
+
+endif
+
+PERL_DEFINES += $(gitexecdir) $(perllibdir) $(localedir)
+
+$(SCRIPT_PERL_GEN): % : %.perl GIT-PERL-DEFINES GIT-PERL-HEADER GIT-VERSION-FILE
 	$(QUIET_GEN)$(RM) $@ $@+ && \
-	INSTLIBDIR='$(perllibdir_SQ)' && \
-	INSTLIBDIR_EXTRA='$(PERLLIB_EXTRA_SQ)' && \
-	INSTLIBDIR="$$INSTLIBDIR$${INSTLIBDIR_EXTRA:+:$$INSTLIBDIR_EXTRA}" && \
 	sed -e '1{' \
 	    -e '	s|#!.*perl|#!$(PERL_PATH_SQ)|' \
-	    -e '	h' \
-	    -e '	s=.*=use lib (split(/$(pathsep)/, $$ENV{GITPERLLIB} || "'"$$INSTLIBDIR"'"));=' \
-	    -e '	H' \
-	    -e '	x' \
+	    -e '	rGIT-PERL-HEADER' \
+	    -e '	G' \
 	    -e '}' \
 	    -e 's/@@GIT_VERSION@@/$(GIT_VERSION)/g' \
 	    $< >$@+ && \
 	chmod +x $@+ && \
 	mv $@+ $@
 
+PERL_DEFINES := $(subst $(space),:,$(PERL_DEFINES))
 GIT-PERL-DEFINES: FORCE
 	@FLAGS='$(PERL_DEFINES)'; \
 	    if test x"$$FLAGS" != x"`cat $@ 2>/dev/null`" ; then \
@@ -2016,6 +2123,22 @@
 		echo "$$FLAGS" >$@; \
 	    fi
 
+GIT-PERL-HEADER: $(PERL_HEADER_TEMPLATE) GIT-PERL-DEFINES Makefile
+	$(QUIET_GEN)$(RM) $@ && \
+	INSTLIBDIR='$(perllibdir_SQ)' && \
+	INSTLIBDIR_EXTRA='$(PERLLIB_EXTRA_SQ)' && \
+	INSTLIBDIR="$$INSTLIBDIR$${INSTLIBDIR_EXTRA:+:$$INSTLIBDIR_EXTRA}" && \
+	sed -e 's=@@PATHSEP@@=$(pathsep)=g' \
+	    -e "s=@@INSTLIBDIR@@=$$INSTLIBDIR=g" \
+	    -e 's=@@PERLLIBDIR_REL@@=$(perllibdir_relative_SQ)=g' \
+	    -e 's=@@GITEXECDIR_REL@@=$(gitexecdir_relative_SQ)=g' \
+	    -e 's=@@LOCALEDIR_REL@@=$(localedir_relative_SQ)=g' \
+	    $< >$@+ && \
+	mv $@+ $@
+
+.PHONY: perllibdir
+perllibdir:
+	@echo '$(perllibdir_SQ)'
 
 .PHONY: gitweb
 gitweb:
@@ -2150,7 +2273,7 @@
 # Dependencies on header files, for platforms that do not support
 # the gcc -MMD option.
 #
-# Dependencies on automatically generated headers such as common-cmds.h
+# Dependencies on automatically generated headers such as command-list.h
 # should _not_ be included here, since they are necessary even when
 # building an object for the first time.
 
@@ -2160,8 +2283,9 @@
 exec-cmd.sp exec-cmd.s exec-cmd.o: GIT-PREFIX
 exec-cmd.sp exec-cmd.s exec-cmd.o: EXTRA_CPPFLAGS = \
 	'-DGIT_EXEC_PATH="$(gitexecdir_SQ)"' \
+	'-DGIT_LOCALE_PATH="$(localedir_relative_SQ)"' \
 	'-DBINDIR="$(bindir_relative_SQ)"' \
-	'-DPREFIX="$(prefix_SQ)"'
+	'-DFALLBACK_RUNTIME_PREFIX="$(prefix_SQ)"'
 
 builtin/init-db.sp builtin/init-db.s builtin/init-db.o: GIT-PREFIX
 builtin/init-db.sp builtin/init-db.s builtin/init-db.o: EXTRA_CPPFLAGS = \
@@ -2177,7 +2301,7 @@
 
 gettext.sp gettext.s gettext.o: GIT-PREFIX
 gettext.sp gettext.s gettext.o: EXTRA_CPPFLAGS = \
-	-DGIT_LOCALE_PATH='"$(localedir_SQ)"'
+	-DGIT_LOCALE_PATH='"$(localedir_relative_SQ)"'
 
 http-push.sp http.sp http-walker.sp remote-curl.sp imap-send.sp: SPARSE_FLAGS += \
 	-DCURL_DISABLE_TYPECHECK
@@ -2337,7 +2461,7 @@
 
 perl/build/lib/%.pm: perl/%.pm
 	$(QUIET_GEN)mkdir -p $(dir $@) && \
-	sed -e 's|@@LOCALEDIR@@|$(localedir_SQ)|g' \
+	sed -e 's|@@LOCALEDIR@@|$(perl_localedir_SQ)|g' \
 	    -e 's|@@NO_PERL_CPAN_FALLBACKS@@|$(NO_PERL_CPAN_FALLBACKS_SQ)|g' \
 	< $< > $@
 
@@ -2529,7 +2653,7 @@
 style:
 	git clang-format --style file --diff --extensions c,h
 
-check: common-cmds.h
+check: command-list.h
 	@if sparse; \
 	then \
 		echo >&2 "Use 'make sparse' instead"; \
@@ -2777,7 +2901,7 @@
 	$(RM) $(TEST_PROGRAMS) $(NO_INSTALL)
 	$(RM) -r bin-wrappers $(dep_dirs)
 	$(RM) -r po/build/
-	$(RM) *.pyc *.pyo */*.pyc */*.pyo common-cmds.h $(ETAGS_TARGET) tags cscope*
+	$(RM) *.pyc *.pyo */*.pyc */*.pyo command-list.h $(ETAGS_TARGET) tags cscope*
 	$(RM) -r $(GIT_TARNAME) .doc-tmp-dir
 	$(RM) $(GIT_TARNAME).tar.gz git-core_$(GIT_VERSION)-*.tar.gz
 	$(RM) $(htmldocs).tar.gz $(manpages).tar.gz
@@ -2795,7 +2919,7 @@
 endif
 	$(RM) GIT-VERSION-FILE GIT-CFLAGS GIT-LDFLAGS GIT-BUILD-OPTIONS
 	$(RM) GIT-USER-AGENT GIT-PREFIX
-	$(RM) GIT-SCRIPT-DEFINES GIT-PERL-DEFINES GIT-PYTHON-VARS
+	$(RM) GIT-SCRIPT-DEFINES GIT-PERL-DEFINES GIT-PERL-HEADER GIT-PYTHON-VARS
 
 .PHONY: all install profile-clean clean strip
 .PHONY: shell_compatibility_test please_set_SHELL_PATH_to_a_more_modern_shell
diff --git a/README.md b/README.md
index f17af66..f920a42 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,9 @@
 available at <https://public-inbox.org/git/>,
 <http://marc.info/?l=git> and other archival sites.
 
+Issues which are security relevant should be disclosed privately to
+the Git Security mailing list <git-security@googlegroups.com>.
+
 The maintainer frequently sends the "What's cooking" reports that
 list the current status of various development topics to the mailing
 list.  The discussion following them give a good reference for
diff --git a/advice.c b/advice.c
index 406efc1..370a56d 100644
--- a/advice.c
+++ b/advice.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "config.h"
+#include "color.h"
 
 int advice_push_update_rejected = 1;
 int advice_push_non_ff_current = 1;
@@ -19,6 +20,34 @@
 int advice_add_embedded_repo = 1;
 int advice_ignored_hook = 1;
 int advice_waiting_for_editor = 1;
+int advice_graft_file_deprecated = 1;
+
+static int advice_use_color = -1;
+static char advice_colors[][COLOR_MAXLEN] = {
+	GIT_COLOR_RESET,
+	GIT_COLOR_YELLOW,	/* HINT */
+};
+
+enum color_advice {
+	ADVICE_COLOR_RESET = 0,
+	ADVICE_COLOR_HINT = 1,
+};
+
+static int parse_advise_color_slot(const char *slot)
+{
+	if (!strcasecmp(slot, "reset"))
+		return ADVICE_COLOR_RESET;
+	if (!strcasecmp(slot, "hint"))
+		return ADVICE_COLOR_HINT;
+	return -1;
+}
+
+static const char *advise_get_color(enum color_advice ix)
+{
+	if (want_color_stderr(advice_use_color))
+		return advice_colors[ix];
+	return "";
+}
 
 static struct {
 	const char *name;
@@ -42,6 +71,7 @@
 	{ "addembeddedrepo", &advice_add_embedded_repo },
 	{ "ignoredhook", &advice_ignored_hook },
 	{ "waitingforeditor", &advice_waiting_for_editor },
+	{ "graftfiledeprecated", &advice_graft_file_deprecated },
 
 	/* make this an alias for backward compatibility */
 	{ "pushnonfastforward", &advice_push_update_rejected }
@@ -59,7 +89,10 @@
 
 	for (cp = buf.buf; *cp; cp = np) {
 		np = strchrnul(cp, '\n');
-		fprintf(stderr,	_("hint: %.*s\n"), (int)(np - cp), cp);
+		fprintf(stderr,	_("%shint: %.*s%s\n"),
+			advise_get_color(ADVICE_COLOR_HINT),
+			(int)(np - cp), cp,
+			advise_get_color(ADVICE_COLOR_RESET));
 		if (*np)
 			np++;
 	}
@@ -68,9 +101,23 @@
 
 int git_default_advice_config(const char *var, const char *value)
 {
-	const char *k;
+	const char *k, *slot_name;
 	int i;
 
+	if (!strcmp(var, "color.advice")) {
+		advice_use_color = git_config_colorbool(var, value);
+		return 0;
+	}
+
+	if (skip_prefix(var, "color.advice.", &slot_name)) {
+		int slot = parse_advise_color_slot(slot_name);
+		if (slot < 0)
+			return 0;
+		if (!value)
+			return config_error_nonbool(var);
+		return color_parse(value, advice_colors[slot]);
+	}
+
 	if (!skip_prefix(var, "advice.", &k))
 		return 0;
 
diff --git a/advice.h b/advice.h
index 70568fa..9f5064e 100644
--- a/advice.h
+++ b/advice.h
@@ -21,6 +21,7 @@
 extern int advice_add_embedded_repo;
 extern int advice_ignored_hook;
 extern int advice_waiting_for_editor;
+extern int advice_graft_file_deprecated;
 
 int git_default_advice_config(const char *var, const char *value);
 __attribute__((format (printf, 1, 2)))
diff --git a/alias.c b/alias.c
index bf146e5..a7e4e57 100644
--- a/alias.c
+++ b/alias.c
@@ -1,9 +1,12 @@
 #include "cache.h"
+#include "alias.h"
 #include "config.h"
+#include "string-list.h"
 
 struct config_alias_data {
 	const char *alias;
 	char *v;
+	struct string_list *list;
 };
 
 static int config_alias_cb(const char *key, const char *value, void *d)
@@ -11,8 +14,16 @@
 	struct config_alias_data *data = d;
 	const char *p;
 
-	if (skip_prefix(key, "alias.", &p) && !strcasecmp(p, data->alias))
-		return git_config_string((const char **)&data->v, key, value);
+	if (!skip_prefix(key, "alias.", &p))
+		return 0;
+
+	if (data->alias) {
+		if (!strcasecmp(p, data->alias))
+			return git_config_string((const char **)&data->v,
+						 key, value);
+	} else if (data->list) {
+		string_list_append(data->list, p);
+	}
 
 	return 0;
 }
@@ -26,6 +37,13 @@
 	return data.v;
 }
 
+void list_aliases(struct string_list *list)
+{
+	struct config_alias_data data = { NULL, NULL, list };
+
+	read_early_config(config_alias_cb, &data);
+}
+
 #define SPLIT_CMDLINE_BAD_ENDING 1
 #define SPLIT_CMDLINE_UNCLOSED_QUOTE 2
 static const char *split_cmdline_errors[] = {
diff --git a/alias.h b/alias.h
new file mode 100644
index 0000000..79933f2
--- /dev/null
+++ b/alias.h
@@ -0,0 +1,12 @@
+#ifndef __ALIAS_H__
+#define __ALIAS_H__
+
+struct string_list;
+
+char *alias_lookup(const char *alias);
+int split_cmdline(char *cmdline, const char ***argv);
+/* Takes a negative value returned by split_cmdline */
+const char *split_cmdline_strerror(int cmdline_errno);
+void list_aliases(struct string_list *list);
+
+#endif
diff --git a/alloc.c b/alloc.c
index 12afadf..cf4f8b6 100644
--- a/alloc.c
+++ b/alloc.c
@@ -93,6 +93,7 @@
 	struct commit *c = alloc_node(&commit_state, sizeof(struct commit));
 	c->object.type = OBJ_COMMIT;
 	c->index = alloc_commit_index();
+	c->graph_pos = COMMIT_NOT_FROM_GRAPH;
 	return c;
 }
 
diff --git a/apply.c b/apply.c
index 7e5792c..d79e615 100644
--- a/apply.c
+++ b/apply.c
@@ -2375,7 +2375,7 @@
 	if (postlen
 	    ? postlen < new_buf - postimage->buf
 	    : postimage->len < new_buf - postimage->buf)
-		die("BUG: caller miscounted postlen: asked %d, orig = %d, used = %d",
+		BUG("caller miscounted postlen: asked %d, orig = %d, used = %d",
 		    (int)postlen, (int) postimage->len, (int)(new_buf - postimage->buf));
 
 	/* Fix the length of the whole thing */
@@ -3509,7 +3509,7 @@
 	unsigned mode = patch->new_mode;
 
 	if (!patch->is_new)
-		die("BUG: patch to %s is not a creation", patch->old_name);
+		BUG("patch to %s is not a creation", patch->old_name);
 
 	pos = cache_name_pos(name, strlen(name));
 	if (pos < 0)
@@ -3860,9 +3860,9 @@
 	if (!patch->is_delete)
 		new_name = patch->new_name;
 
-	if (old_name && !verify_path(old_name))
+	if (old_name && !verify_path(old_name, patch->old_mode))
 		return error(_("invalid path '%s'"), old_name);
-	if (new_name && !verify_path(new_name))
+	if (new_name && !verify_path(new_name, patch->new_mode))
 		return error(_("invalid path '%s'"), new_name);
 	return 0;
 }
@@ -4058,7 +4058,7 @@
 {
 	struct patch *patch;
 	struct index_state result = { NULL };
-	static struct lock_file lock;
+	struct lock_file lock = LOCK_INIT;
 	int res;
 
 	/* Once we start supporting the reverse patch, it may be
diff --git a/archive-tar.c b/archive-tar.c
index 3563bcb..b6f58dd 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -276,7 +276,7 @@
 		memcpy(header.name, path, pathlen);
 
 	if (S_ISREG(mode) && !args->convert &&
-	    oid_object_info(oid, &size) == OBJ_BLOB &&
+	    oid_object_info(the_repository, oid, &size) == OBJ_BLOB &&
 	    size > big_file_threshold)
 		buffer = NULL;
 	else if (S_ISLNK(mode) || S_ISREG(mode)) {
@@ -441,7 +441,7 @@
 	int r;
 
 	if (!ar->data)
-		die("BUG: tar-filter archiver called with no filter defined");
+		BUG("tar-filter archiver called with no filter defined");
 
 	strbuf_addstr(&cmd, ar->data);
 	if (args->compression_level >= 0)
diff --git a/archive-zip.c b/archive-zip.c
index 6b20bce..74f3fe9 100644
--- a/archive-zip.c
+++ b/archive-zip.c
@@ -325,7 +325,8 @@
 		compressed_size = 0;
 		buffer = NULL;
 	} else if (S_ISREG(mode) || S_ISLNK(mode)) {
-		enum object_type type = oid_object_info(oid, &size);
+		enum object_type type = oid_object_info(the_repository, oid,
+							&size);
 
 		method = 0;
 		attr2 = S_ISLNK(mode) ? ((mode | 0777) << 16) :
diff --git a/archive.c b/archive.c
index 93ab175..4fe7bec 100644
--- a/archive.c
+++ b/archive.c
@@ -411,11 +411,9 @@
 }
 
 #define OPT__COMPR(s, v, h, p) \
-	{ OPTION_SET_INT, (s), NULL, (v), NULL, (h), \
-	  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, (p) }
+	OPT_SET_INT_F(s, NULL, v, h, p, PARSE_OPT_NONEG)
 #define OPT__COMPR_HIDDEN(s, v, p) \
-	{ OPTION_SET_INT, (s), NULL, (v), NULL, "", \
-	  PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_HIDDEN, NULL, (p) }
+	OPT_SET_INT_F(s, NULL, v, "", p, PARSE_OPT_NONEG | PARSE_OPT_HIDDEN)
 
 static int parse_archive_args(int argc, const char **argv,
 		const struct archiver **ar, struct archiver_args *args,
diff --git a/argv-array.c b/argv-array.c
index 5d370fa..f352ea9 100644
--- a/argv-array.c
+++ b/argv-array.c
@@ -21,12 +21,13 @@
 	array->argv[array->argc] = NULL;
 }
 
-void argv_array_push(struct argv_array *array, const char *value)
+const char *argv_array_push(struct argv_array *array, const char *value)
 {
 	argv_array_push_nodup(array, xstrdup(value));
+	return array->argv[array->argc - 1];
 }
 
-void argv_array_pushf(struct argv_array *array, const char *fmt, ...)
+const char *argv_array_pushf(struct argv_array *array, const char *fmt, ...)
 {
 	va_list ap;
 	struct strbuf v = STRBUF_INIT;
@@ -36,6 +37,7 @@
 	va_end(ap);
 
 	argv_array_push_nodup(array, strbuf_detach(&v, NULL));
+	return array->argv[array->argc - 1];
 }
 
 void argv_array_pushl(struct argv_array *array, ...)
@@ -64,6 +66,26 @@
 	array->argc--;
 }
 
+void argv_array_split(struct argv_array *array, const char *to_split)
+{
+	while (isspace(*to_split))
+		to_split++;
+	for (;;) {
+		const char *p = to_split;
+
+		if (!*p)
+			break;
+
+		while (*p && !isspace(*p))
+			p++;
+		argv_array_push_nodup(array, xstrndup(to_split, p - to_split));
+
+		while (isspace(*p))
+			p++;
+		to_split = p;
+	}
+}
+
 void argv_array_clear(struct argv_array *array)
 {
 	if (array->argv != empty_argv) {
diff --git a/argv-array.h b/argv-array.h
index 29056e4..a39ba43 100644
--- a/argv-array.h
+++ b/argv-array.h
@@ -12,13 +12,15 @@
 #define ARGV_ARRAY_INIT { empty_argv, 0, 0 }
 
 void argv_array_init(struct argv_array *);
-void argv_array_push(struct argv_array *, const char *);
+const char *argv_array_push(struct argv_array *, const char *);
 __attribute__((format (printf,2,3)))
-void argv_array_pushf(struct argv_array *, const char *fmt, ...);
+const char *argv_array_pushf(struct argv_array *, const char *fmt, ...);
 LAST_ARG_MUST_BE_NULL
 void argv_array_pushl(struct argv_array *, ...);
 void argv_array_pushv(struct argv_array *, const char **);
 void argv_array_pop(struct argv_array *);
+/* Splits by whitespace; does not handle quoted arguments! */
+void argv_array_split(struct argv_array *, const char *);
 void argv_array_clear(struct argv_array *);
 const char **argv_array_detach(struct argv_array *);
 
diff --git a/attr.c b/attr.c
index 03a678f..067fb9e 100644
--- a/attr.c
+++ b/attr.c
@@ -157,7 +157,7 @@
 
 	size = hashmap_get_size(&map->map);
 	if (size < check->all_attrs_nr)
-		die("BUG: interned attributes shouldn't be deleted");
+		BUG("interned attributes shouldn't be deleted");
 
 	/*
 	 * If the number of attributes in the global dictionary has increased
@@ -541,7 +541,7 @@
 			break;
 
 	if (i >= check_vector.nr)
-		die("BUG: no entry found");
+		BUG("no entry found");
 
 	/* shift entries over */
 	for (; i < check_vector.nr - 1; i++)
@@ -599,11 +599,11 @@
 		const struct git_attr *attr;
 		param = va_arg(params, const char *);
 		if (!param)
-			die("BUG: counted %d != ended at %d",
+			BUG("counted %d != ended at %d",
 			    check->nr, cnt);
 		attr = git_attr(param);
 		if (!attr)
-			die("BUG: %s: not a valid attribute name", param);
+			BUG("%s: not a valid attribute name", param);
 		check->items[cnt].attr = attr;
 	}
 	va_end(params);
@@ -714,7 +714,7 @@
 			    struct index_state *istate)
 {
 	if (is_bare_repository() && new_direction != GIT_ATTR_INDEX)
-		die("BUG: non-INDEX attr direction in a bare repo");
+		BUG("non-INDEX attr direction in a bare repo");
 
 	if (new_direction != direction)
 		drop_all_attr_stacks();
diff --git a/blame.c b/blame.c
index 78c9808..14d0e0b 100644
--- a/blame.c
+++ b/blame.c
@@ -81,7 +81,7 @@
 		unsigned mode;
 
 		if (!get_tree_entry(commit_oid, path, &blob_oid, &mode) &&
-		    oid_object_info(&blob_oid, NULL) == OBJ_BLOB)
+		    oid_object_info(the_repository, &blob_oid, NULL) == OBJ_BLOB)
 			return;
 	}
 
@@ -504,7 +504,7 @@
 		return 0;
 	if (get_tree_entry(&origin->commit->object.oid, origin->path, &origin->blob_oid, &origin->mode))
 		goto error_out;
-	if (oid_object_info(&origin->blob_oid, NULL) != OBJ_BLOB)
+	if (oid_object_info(the_repository, &origin->blob_oid, NULL) != OBJ_BLOB)
 		goto error_out;
 	return 0;
  error_out:
@@ -551,10 +551,10 @@
 	diff_setup_done(&diff_opts);
 
 	if (is_null_oid(&origin->commit->object.oid))
-		do_diff_cache(&parent->tree->object.oid, &diff_opts);
+		do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
 	else
-		diff_tree_oid(&parent->tree->object.oid,
-			      &origin->commit->tree->object.oid,
+		diff_tree_oid(get_commit_tree_oid(parent),
+			      get_commit_tree_oid(origin->commit),
 			      "", &diff_opts);
 	diffcore_std(&diff_opts);
 
@@ -620,10 +620,10 @@
 	diff_setup_done(&diff_opts);
 
 	if (is_null_oid(&origin->commit->object.oid))
-		do_diff_cache(&parent->tree->object.oid, &diff_opts);
+		do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
 	else
-		diff_tree_oid(&parent->tree->object.oid,
-			      &origin->commit->tree->object.oid,
+		diff_tree_oid(get_commit_tree_oid(parent),
+			      get_commit_tree_oid(origin->commit),
 			      "", &diff_opts);
 	diffcore_std(&diff_opts);
 
@@ -1255,10 +1255,10 @@
 		diff_opts.flags.find_copies_harder = 1;
 
 	if (is_null_oid(&target->commit->object.oid))
-		do_diff_cache(&parent->tree->object.oid, &diff_opts);
+		do_diff_cache(get_commit_tree_oid(parent), &diff_opts);
 	else
-		diff_tree_oid(&parent->tree->object.oid,
-			      &target->commit->tree->object.oid,
+		diff_tree_oid(get_commit_tree_oid(parent),
+			      get_commit_tree_oid(target->commit),
 			      "", &diff_opts);
 
 	if (!diff_opts.flags.find_copies_harder)
@@ -1806,7 +1806,7 @@
 			l->item = c;
 			if (add_decoration(&sb->revs->children,
 					   &c->parents->item->object, l))
-				die("BUG: not unique item in first-parent chain");
+				BUG("not unique item in first-parent chain");
 			c = c->parents->item;
 		}
 
diff --git a/branch.c b/branch.c
index 2672054..f967c98 100644
--- a/branch.c
+++ b/branch.c
@@ -3,12 +3,13 @@
 #include "config.h"
 #include "branch.h"
 #include "refs.h"
+#include "refspec.h"
 #include "remote.h"
 #include "commit.h"
 #include "worktree.h"
 
 struct tracking {
-	struct refspec spec;
+	struct refspec_item spec;
 	char *src;
 	const char *remote;
 	int matches;
@@ -218,8 +219,8 @@
 static int check_tracking_branch(struct remote *remote, void *cb_data)
 {
 	char *tracking_branch = cb_data;
-	struct refspec query;
-	memset(&query, 0, sizeof(struct refspec));
+	struct refspec_item query;
+	memset(&query, 0, sizeof(struct refspec_item));
 	query.dst = tracking_branch;
 	return !remote_find_tracking(remote, &query);
 }
diff --git a/builtin.h b/builtin.h
index 42378f3..4e0f647 100644
--- a/builtin.h
+++ b/builtin.h
@@ -149,6 +149,7 @@
 extern int cmd_clean(int argc, const char **argv, const char *prefix);
 extern int cmd_column(int argc, const char **argv, const char *prefix);
 extern int cmd_commit(int argc, const char **argv, const char *prefix);
+extern int cmd_commit_graph(int argc, const char **argv, const char *prefix);
 extern int cmd_commit_tree(int argc, const char **argv, const char *prefix);
 extern int cmd_config(int argc, const char **argv, const char *prefix);
 extern int cmd_count_objects(int argc, const char **argv, const char *prefix);
@@ -215,6 +216,7 @@
 extern int cmd_revert(int argc, const char **argv, const char *prefix);
 extern int cmd_rm(int argc, const char **argv, const char *prefix);
 extern int cmd_send_pack(int argc, const char **argv, const char *prefix);
+extern int cmd_serve(int argc, const char **argv, const char *prefix);
 extern int cmd_shortlog(int argc, const char **argv, const char *prefix);
 extern int cmd_show(int argc, const char **argv, const char *prefix);
 extern int cmd_show_branch(int argc, const char **argv, const char *prefix);
@@ -231,6 +233,7 @@
 extern int cmd_update_server_info(int argc, const char **argv, const char *prefix);
 extern int cmd_upload_archive(int argc, const char **argv, const char *prefix);
 extern int cmd_upload_archive_writer(int argc, const char **argv, const char *prefix);
+extern int cmd_upload_pack(int argc, const char **argv, const char *prefix);
 extern int cmd_var(int argc, const char **argv, const char *prefix);
 extern int cmd_verify_commit(int argc, const char **argv, const char *prefix);
 extern int cmd_verify_tag(int argc, const char **argv, const char *prefix);
diff --git a/builtin/add.c b/builtin/add.c
index c9e2619..8a155dd 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -265,8 +265,6 @@
 	return 0;
 }
 
-static struct lock_file lock_file;
-
 static const char ignore_error[] =
 N_("The following paths are ignored by one of your .gitignore files:\n");
 
@@ -393,6 +391,7 @@
 	int add_new_files;
 	int require_pathspec;
 	char *seen = NULL;
+	struct lock_file lock_file = LOCK_INIT;
 
 	git_config(add_config, NULL);
 
diff --git a/builtin/am.c b/builtin/am.c
index d834f9e..2fc2d1e 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -403,11 +403,11 @@
 	struct strbuf sb = STRBUF_INIT;
 
 	if (read_state_file(&sb, state, "next", 1) < 0)
-		die("BUG: state file 'next' does not exist");
+		BUG("state file 'next' does not exist");
 	state->cur = strtol(sb.buf, NULL, 10);
 
 	if (read_state_file(&sb, state, "last", 1) < 0)
-		die("BUG: state file 'last' does not exist");
+		BUG("state file 'last' does not exist");
 	state->last = strtol(sb.buf, NULL, 10);
 
 	if (read_author_script(state) < 0)
@@ -986,7 +986,7 @@
 	case PATCH_FORMAT_MBOXRD:
 		return split_mail_mbox(state, paths, keep_cr, 1);
 	default:
-		die("BUG: invalid patch_format");
+		BUG("invalid patch_format");
 	}
 	return -1;
 }
@@ -1041,7 +1041,7 @@
 		str = "b";
 		break;
 	default:
-		die("BUG: invalid value for state->keep");
+		BUG("invalid value for state->keep");
 	}
 
 	write_state_text(state, "keep", str);
@@ -1058,7 +1058,7 @@
 		str = "t";
 		break;
 	default:
-		die("BUG: invalid value for state->scissors");
+		BUG("invalid value for state->scissors");
 	}
 	write_state_text(state, "scissors", str);
 
@@ -1216,7 +1216,7 @@
 		mi.keep_non_patch_brackets_in_subject = 1;
 		break;
 	default:
-		die("BUG: invalid value for state->keep");
+		BUG("invalid value for state->keep");
 	}
 
 	if (state->message_id)
@@ -1232,7 +1232,7 @@
 		mi.use_scissors = 1;
 		break;
 	default:
-		die("BUG: invalid value for state->scissors");
+		BUG("invalid value for state->scissors");
 	}
 
 	mi.input = xfopen(mail, "r");
@@ -1463,7 +1463,7 @@
 	int options = 0;
 
 	if (init_apply_state(&apply_state, NULL))
-		die("BUG: init_apply_state() failed");
+		BUG("init_apply_state() failed");
 
 	argv_array_push(&apply_opts, "apply");
 	argv_array_pushv(&apply_opts, state->git_apply_opts.argv);
@@ -1489,7 +1489,7 @@
 		apply_state.apply_verbosity = verbosity_silent;
 
 	if (check_apply_state(&apply_state, force_apply))
-		die("BUG: check_apply_state() failed");
+		BUG("check_apply_state() failed");
 
 	argv_array_push(&apply_paths, am_path(state, "patch"));
 
@@ -1542,7 +1542,7 @@
 	char *their_tree_name;
 
 	if (get_oid("HEAD", &our_tree) < 0)
-		hashcpy(our_tree.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&our_tree, the_hash_algo->empty_tree);
 
 	if (build_fake_ancestor(state, index_path))
 		return error("could not build fake ancestor");
@@ -2042,7 +2042,7 @@
 	am_rerere_clear();
 
 	if (get_oid("HEAD", &head))
-		hashcpy(head.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&head, the_hash_algo->empty_tree);
 
 	if (clean_index(&head, &head))
 		die(_("failed to clean index"));
@@ -2105,11 +2105,11 @@
 	curr_branch = resolve_refdup("HEAD", 0, &curr_head, NULL);
 	has_curr_head = curr_branch && !is_null_oid(&curr_head);
 	if (!has_curr_head)
-		hashcpy(curr_head.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&curr_head, the_hash_algo->empty_tree);
 
 	has_orig_head = !get_oid("ORIG_HEAD", &orig_head);
 	if (!has_orig_head)
-		hashcpy(orig_head.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&orig_head, the_hash_algo->empty_tree);
 
 	clean_index(&curr_head, &orig_head);
 
@@ -2231,12 +2231,12 @@
 			N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
 		OPT_BOOL('m', "message-id", &state.message_id,
 			N_("pass -m flag to git-mailinfo")),
-		{ OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
-		  N_("pass --keep-cr flag to git-mailsplit for mbox format"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
-		{ OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
-		  N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
+		OPT_SET_INT_F(0, "keep-cr", &keep_cr,
+			N_("pass --keep-cr flag to git-mailsplit for mbox format"),
+			1, PARSE_OPT_NONEG),
+		OPT_SET_INT_F(0, "no-keep-cr", &keep_cr,
+			N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
+			0, PARSE_OPT_NONEG),
 		OPT_BOOL('c', "scissors", &state.scissors,
 			N_("strip everything before a scissors line")),
 		OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
@@ -2407,7 +2407,7 @@
 		ret = show_patch(&state);
 		break;
 	default:
-		die("BUG: invalid resume value");
+		BUG("invalid resume value");
 	}
 
 	am_state_release(&state);
diff --git a/builtin/blame.c b/builtin/blame.c
index db38c0b..4202584 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -7,6 +7,7 @@
 
 #include "cache.h"
 #include "config.h"
+#include "color.h"
 #include "builtin.h"
 #include "commit.h"
 #include "diff.h"
@@ -23,6 +24,7 @@
 #include "dir.h"
 #include "progress.h"
 #include "blame.h"
+#include "string-list.h"
 
 static char blame_usage[] = N_("git blame [<options>] [<rev-opts>] [<rev>] [--] <file>");
 
@@ -46,6 +48,8 @@
 static int abbrev = -1;
 static int no_whole_file_rename;
 static int show_progress;
+static char repeated_meta_color[COLOR_MAXLEN];
+static int coloring_mode;
 
 static struct date_mode blame_date_mode = { DATE_ISO8601 };
 static size_t blame_date_width;
@@ -316,10 +320,12 @@
 #define OUTPUT_PORCELAIN	010
 #define OUTPUT_SHOW_NAME	020
 #define OUTPUT_SHOW_NUMBER	040
-#define OUTPUT_SHOW_SCORE      0100
-#define OUTPUT_NO_AUTHOR       0200
+#define OUTPUT_SHOW_SCORE	0100
+#define OUTPUT_NO_AUTHOR	0200
 #define OUTPUT_SHOW_EMAIL	0400
-#define OUTPUT_LINE_PORCELAIN 01000
+#define OUTPUT_LINE_PORCELAIN	01000
+#define OUTPUT_COLOR_LINE	02000
+#define OUTPUT_SHOW_AGE_WITH_COLOR	04000
 
 static void emit_porcelain_details(struct blame_origin *suspect, int repeat)
 {
@@ -367,6 +373,63 @@
 		putchar('\n');
 }
 
+static struct color_field {
+	timestamp_t hop;
+	char col[COLOR_MAXLEN];
+} *colorfield;
+static int colorfield_nr, colorfield_alloc;
+
+static void parse_color_fields(const char *s)
+{
+	struct string_list l = STRING_LIST_INIT_DUP;
+	struct string_list_item *item;
+	enum { EXPECT_DATE, EXPECT_COLOR } next = EXPECT_COLOR;
+
+	colorfield_nr = 0;
+
+	/* Ideally this would be stripped and split at the same time? */
+	string_list_split(&l, s, ',', -1);
+	ALLOC_GROW(colorfield, colorfield_nr + 1, colorfield_alloc);
+
+	for_each_string_list_item(item, &l) {
+		switch (next) {
+		case EXPECT_DATE:
+			colorfield[colorfield_nr].hop = approxidate(item->string);
+			next = EXPECT_COLOR;
+			colorfield_nr++;
+			ALLOC_GROW(colorfield, colorfield_nr + 1, colorfield_alloc);
+			break;
+		case EXPECT_COLOR:
+			if (color_parse(item->string, colorfield[colorfield_nr].col))
+				die(_("expecting a color: %s"), item->string);
+			next = EXPECT_DATE;
+			break;
+		}
+	}
+
+	if (next == EXPECT_COLOR)
+		die (_("must end with a color"));
+
+	colorfield[colorfield_nr].hop = TIME_MAX;
+}
+
+static void setup_default_color_by_age(void)
+{
+	parse_color_fields("blue,12 month ago,white,1 month ago,red");
+}
+
+static void determine_line_heat(struct blame_entry *ent, const char **dest_color)
+{
+	int i = 0;
+	struct commit_info ci;
+	get_commit_info(ent->suspect->commit, &ci, 1);
+
+	while (i < colorfield_nr && ci.author_time > colorfield[i].hop)
+		i++;
+
+	*dest_color = colorfield[i].col;
+}
+
 static void emit_other(struct blame_scoreboard *sb, struct blame_entry *ent, int opt)
 {
 	int cnt;
@@ -375,15 +438,35 @@
 	struct commit_info ci;
 	char hex[GIT_MAX_HEXSZ + 1];
 	int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
+	const char *default_color = NULL, *color = NULL, *reset = NULL;
 
 	get_commit_info(suspect->commit, &ci, 1);
 	oid_to_hex_r(hex, &suspect->commit->object.oid);
 
 	cp = blame_nth_line(sb, ent->lno);
+
+	if (opt & OUTPUT_SHOW_AGE_WITH_COLOR) {
+		determine_line_heat(ent, &default_color);
+		color = default_color;
+		reset = GIT_COLOR_RESET;
+	}
+
 	for (cnt = 0; cnt < ent->num_lines; cnt++) {
 		char ch;
 		int length = (opt & OUTPUT_LONG_OBJECT_NAME) ? GIT_SHA1_HEXSZ : abbrev;
 
+		if (opt & OUTPUT_COLOR_LINE) {
+			if (cnt > 0) {
+				color = repeated_meta_color;
+				reset = GIT_COLOR_RESET;
+			} else  {
+				color = default_color ? default_color : NULL;
+				reset = default_color ? GIT_COLOR_RESET : NULL;
+			}
+		}
+		if (color)
+			fputs(color, stdout);
+
 		if (suspect->commit->object.flags & UNINTERESTING) {
 			if (blank_boundary)
 				memset(hex, ' ', length);
@@ -433,6 +516,8 @@
 			printf(" %*d) ",
 			       max_digits, ent->lno + 1 + cnt);
 		}
+		if (reset)
+			fputs(reset, stdout);
 		do {
 			ch = *cp++;
 			putchar(ch);
@@ -607,6 +692,30 @@
 		parse_date_format(value, &blame_date_mode);
 		return 0;
 	}
+	if (!strcmp(var, "color.blame.repeatedlines")) {
+		if (color_parse_mem(value, strlen(value), repeated_meta_color))
+			warning(_("invalid color '%s' in color.blame.repeatedLines"),
+				value);
+		return 0;
+	}
+	if (!strcmp(var, "color.blame.highlightrecent")) {
+		parse_color_fields(value);
+		return 0;
+	}
+
+	if (!strcmp(var, "blame.coloring")) {
+		if (!strcmp(value, "repeatedLines")) {
+			coloring_mode |= OUTPUT_COLOR_LINE;
+		} else if (!strcmp(value, "highlightRecent")) {
+			coloring_mode |= OUTPUT_SHOW_AGE_WITH_COLOR;
+		} else if (!strcmp(value, "none")) {
+			coloring_mode &= ~(OUTPUT_COLOR_LINE |
+					    OUTPUT_SHOW_AGE_WITH_COLOR);
+		} else {
+			warning(_("invalid value for blame.coloring"));
+			return 0;
+		}
+	}
 
 	if (git_diff_heuristic_config(var, value, cb) < 0)
 		return -1;
@@ -655,7 +764,7 @@
 
 	if (get_oid(name, &oid))
 		return 0;
-	return OBJ_NONE < oid_object_info(&oid, NULL);
+	return OBJ_NONE < oid_object_info(the_repository, &oid, NULL);
 }
 
 int cmd_blame(int argc, const char **argv, const char *prefix)
@@ -690,6 +799,8 @@
 		OPT_BIT('s', NULL, &output_option, N_("Suppress author name and timestamp (Default: off)"), OUTPUT_NO_AUTHOR),
 		OPT_BIT('e', "show-email", &output_option, N_("Show author email instead of name (Default: off)"), OUTPUT_SHOW_EMAIL),
 		OPT_BIT('w', NULL, &xdl_opts, N_("Ignore whitespace differences"), XDF_IGNORE_WHITESPACE),
+		OPT_BIT(0, "color-lines", &output_option, N_("color redundant metadata from previous line differently"), OUTPUT_COLOR_LINE),
+		OPT_BIT(0, "color-by-age", &output_option, N_("color lines by age"), OUTPUT_SHOW_AGE_WITH_COLOR),
 
 		/*
 		 * The following two options are parsed by parse_revision_opt()
@@ -714,6 +825,7 @@
 	unsigned int range_i;
 	long anchor;
 
+	setup_default_color_by_age();
 	git_config(git_blame_config, &output_option);
 	init_revisions(&revs, NULL);
 	revs.date_mode = blame_date_mode;
@@ -949,8 +1061,17 @@
 
 	blame_coalesce(&sb);
 
-	if (!(output_option & OUTPUT_PORCELAIN))
+	if (!(output_option & (OUTPUT_COLOR_LINE | OUTPUT_SHOW_AGE_WITH_COLOR)))
+		output_option |= coloring_mode;
+
+	if (!(output_option & OUTPUT_PORCELAIN)) {
 		find_alignment(&sb, &output_option);
+		if (!*repeated_meta_color &&
+		    (output_option & OUTPUT_COLOR_LINE))
+			strcpy(repeated_meta_color, GIT_COLOR_CYAN);
+	}
+	if (output_option & OUTPUT_ANNOTATE_COMPAT)
+		output_option &= ~(OUTPUT_COLOR_LINE | OUTPUT_SHOW_AGE_WITH_COLOR);
 
 	output(&sb, output_option);
 	free((void *)sb.final_buf);
diff --git a/builtin/branch.c b/builtin/branch.c
index 5bd2a0d..d53f6e2 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -391,7 +391,6 @@
 	struct ref_array array;
 	int maxwidth = 0;
 	const char *remote_prefix = "";
-	struct strbuf out = STRBUF_INIT;
 	char *to_free = NULL;
 
 	/*
@@ -419,7 +418,10 @@
 	ref_array_sort(sorting, &array);
 
 	for (i = 0; i < array.nr; i++) {
-		format_ref_array_item(array.items[i], format, &out);
+		struct strbuf out = STRBUF_INIT;
+		struct strbuf err = STRBUF_INIT;
+		if (format_ref_array_item(array.items[i], format, &out, &err))
+			die("%s", err.buf);
 		if (column_active(colopts)) {
 			assert(!filter->verbose && "--column and --verbose are incompatible");
 			 /* format to a string_list to let print_columns() do its job */
@@ -428,6 +430,7 @@
 			fwrite(out.buf, 1, out.len, stdout);
 			putchar('\n');
 		}
+		strbuf_release(&err);
 		strbuf_release(&out);
 	}
 
@@ -497,7 +500,7 @@
 
 	if (!skip_prefix(oldref.buf, "refs/heads/", &interpreted_oldname) ||
 	    !skip_prefix(newref.buf, "refs/heads/", &interpreted_newname)) {
-		die("BUG: expected prefix missing for refs");
+		BUG("expected prefix missing for refs");
 	}
 
 	if (copy)
@@ -589,8 +592,8 @@
 		OPT__QUIET(&quiet, N_("suppress informational messages")),
 		OPT_SET_INT('t', "track",  &track, N_("set up tracking mode (see git-pull(1))"),
 			BRANCH_TRACK_EXPLICIT),
-		{ OPTION_SET_INT, 0, "set-upstream", &track, NULL, N_("do not use"),
-			PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, BRANCH_TRACK_OVERRIDE },
+		OPT_SET_INT_F(0, "set-upstream", &track, N_("do not use"),
+			BRANCH_TRACK_OVERRIDE, PARSE_OPT_HIDDEN),
 		OPT_STRING('u', "set-upstream-to", &new_upstream, N_("upstream"), N_("change the upstream info")),
 		OPT_BOOL(0, "unset-upstream", &unset_upstream, N_("Unset the upstream info")),
 		OPT__COLOR(&branch_use_color, N_("use colored output")),
diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 2c46d25..665b581 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -77,7 +77,7 @@
 	switch (opt) {
 	case 't':
 		oi.type_name = &sb;
-		if (oid_object_info_extended(&oid, &oi, flags) < 0)
+		if (oid_object_info_extended(the_repository, &oid, &oi, flags) < 0)
 			die("git cat-file: could not get object info");
 		if (sb.len) {
 			printf("%s\n", sb.buf);
@@ -88,7 +88,7 @@
 
 	case 's':
 		oi.sizep = &size;
-		if (oid_object_info_extended(&oid, &oi, flags) < 0)
+		if (oid_object_info_extended(the_repository, &oid, &oi, flags) < 0)
 			die("git cat-file: could not get object info");
 		printf("%lu\n", size);
 		return 0;
@@ -116,7 +116,7 @@
 		/* else fallthrough */
 
 	case 'p':
-		type = oid_object_info(&oid, NULL);
+		type = oid_object_info(the_repository, &oid, NULL);
 		if (type < 0)
 			die("Not a valid object name %s", obj_name);
 
@@ -140,7 +140,7 @@
 	case 0:
 		if (type_from_string(exp_type) == OBJ_BLOB) {
 			struct object_id blob_oid;
-			if (oid_object_info(&oid, NULL) == OBJ_TAG) {
+			if (oid_object_info(the_repository, &oid, NULL) == OBJ_TAG) {
 				char *buffer = read_object_file(&oid, &type,
 								&size);
 				const char *target;
@@ -151,7 +151,7 @@
 			} else
 				oidcpy(&blob_oid, &oid);
 
-			if (oid_object_info(&blob_oid, NULL) == OBJ_BLOB)
+			if (oid_object_info(the_repository, &blob_oid, NULL) == OBJ_BLOB)
 				return stream_blob_to_fd(1, &blob_oid, NULL, 0);
 			/*
 			 * we attempted to dereference a tag to a blob
@@ -312,7 +312,7 @@
 					die("could not convert '%s' %s",
 					    oid_to_hex(oid), data->rest);
 			} else
-				die("BUG: invalid cmdmode: %c", opt->cmdmode);
+				BUG("invalid cmdmode: %c", opt->cmdmode);
 			batch_write(opt, contents, size);
 			free(contents);
 		} else if (stream_blob_to_fd(1, oid, NULL, 0) < 0)
@@ -342,7 +342,7 @@
 	struct strbuf buf = STRBUF_INIT;
 
 	if (!data->skip_object_info &&
-	    oid_object_info_extended(&data->oid, &data->info,
+	    oid_object_info_extended(the_repository, &data->oid, &data->info,
 				     OBJECT_INFO_LOOKUP_REPLACE) < 0) {
 		printf("%s missing\n",
 		       obj_name ? obj_name : oid_to_hex(&data->oid));
@@ -387,7 +387,7 @@
 			       (uintmax_t)strlen(obj_name), obj_name);
 			break;
 		default:
-			die("BUG: unknown get_sha1_with_context result %d\n",
+			BUG("unknown get_sha1_with_context result %d\n",
 			       result);
 			break;
 		}
diff --git a/builtin/checkout.c b/builtin/checkout.c
index b49b582..2e1d237 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -484,7 +484,8 @@
 
 	resolve_undo_clear();
 	if (opts->force) {
-		ret = reset_tree(new_branch_info->commit->tree, opts, 1, writeout_error);
+		ret = reset_tree(get_commit_tree(new_branch_info->commit),
+				 opts, 1, writeout_error);
 		if (ret)
 			return ret;
 	} else {
@@ -526,6 +527,7 @@
 		init_tree_desc(&trees[1], tree->buffer, tree->size);
 
 		ret = unpack_trees(2, trees, &topts);
+		clear_unpack_trees_porcelain(&topts);
 		if (ret == -1) {
 			/*
 			 * Unpack couldn't do a trivial merge; either
@@ -570,18 +572,23 @@
 			o.verbosity = 0;
 			work = write_tree_from_memory(&o);
 
-			ret = reset_tree(new_branch_info->commit->tree, opts, 1,
+			ret = reset_tree(get_commit_tree(new_branch_info->commit),
+					 opts, 1,
 					 writeout_error);
 			if (ret)
 				return ret;
 			o.ancestor = old_branch_info->name;
 			o.branch1 = new_branch_info->name;
 			o.branch2 = "local";
-			ret = merge_trees(&o, new_branch_info->commit->tree, work,
-				old_branch_info->commit->tree, &result);
+			ret = merge_trees(&o,
+					  get_commit_tree(new_branch_info->commit),
+					  work,
+					  get_commit_tree(old_branch_info->commit),
+					  &result);
 			if (ret < 0)
 				exit(128);
-			ret = reset_tree(new_branch_info->commit->tree, opts, 0,
+			ret = reset_tree(get_commit_tree(new_branch_info->commit),
+					 opts, 0,
 					 writeout_error);
 			strbuf_release(&o.obuf);
 			if (ret)
@@ -1002,7 +1009,7 @@
 		*source_tree = parse_tree_indirect(rev);
 	} else {
 		parse_commit_or_die(new_branch_info->commit);
-		*source_tree = new_branch_info->commit->tree;
+		*source_tree = get_commit_tree(new_branch_info->commit);
 	}
 
 	if (!*source_tree)                   /* case (1): want a tree */
diff --git a/builtin/clone.c b/builtin/clone.c
index 7df5932..99e73da 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -14,6 +14,7 @@
 #include "parse-options.h"
 #include "fetch-pack.h"
 #include "refs.h"
+#include "refspec.h"
 #include "tree.h"
 #include "tree-walk.h"
 #include "unpack-trees.h"
@@ -546,7 +547,7 @@
 }
 
 static struct ref *wanted_peer_refs(const struct ref *refs,
-		struct refspec *refspec)
+		struct refspec_item *refspec)
 {
 	struct ref *head = copy_ref(find_ref_by_name(refs, "HEAD"));
 	struct ref *local_refs = head;
@@ -823,7 +824,7 @@
 			} else if (remote_head_points_at) {
 				const char *head = remote_head_points_at->name;
 				if (!skip_prefix(head, "refs/heads/", &head))
-					die("BUG: remote HEAD points at non-head?");
+					BUG("remote HEAD points at non-head?");
 
 				strbuf_addf(&value, "+%s:%s%s", remote_head_points_at->name,
 						branch_top->buf, head);
@@ -894,8 +895,7 @@
 	int err = 0, complete_refs_before_fetch = 1;
 	int submodule_progress;
 
-	struct refspec *refspec;
-	const char *fetch_pattern;
+	struct refspec_item refspec;
 
 	fetch_if_missing = 0;
 
@@ -1077,8 +1077,7 @@
 	if (option_required_reference.nr || option_optional_reference.nr)
 		setup_reference();
 
-	fetch_pattern = value.buf;
-	refspec = parse_fetch_refspec(1, &fetch_pattern);
+	refspec_item_init(&refspec, value.buf, REFSPEC_FETCH);
 
 	strbuf_reset(&value);
 
@@ -1135,10 +1134,10 @@
 	if (transport->smart_options && !deepen && !filter_options.choice)
 		transport->smart_options->check_self_contained_and_connected = 1;
 
-	refs = transport_get_remote_refs(transport);
+	refs = transport_get_remote_refs(transport, NULL);
 
 	if (refs) {
-		mapped_refs = wanted_peer_refs(refs, refspec);
+		mapped_refs = wanted_peer_refs(refs, &refspec);
 		/*
 		 * transport_get_remote_refs() may return refs with null sha-1
 		 * in mapped_refs (see struct transport->get_refs_list
@@ -1232,6 +1231,6 @@
 	strbuf_release(&value);
 	junk_mode = JUNK_LEAVE_ALL;
 
-	free(refspec);
+	refspec_item_clear(&refspec);
 	return err;
 }
diff --git a/builtin/column.c b/builtin/column.c
index 0c3223d..5228ccf 100644
--- a/builtin/column.c
+++ b/builtin/column.c
@@ -42,7 +42,6 @@
 		git_config(column_config, NULL);
 
 	memset(&copts, 0, sizeof(copts));
-	copts.width = term_columns();
 	copts.padding = 1;
 	argc = parse_options(argc, argv, "", options, builtin_column_usage, 0);
 	if (argc)
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
new file mode 100644
index 0000000..37420ae
--- /dev/null
+++ b/builtin/commit-graph.c
@@ -0,0 +1,171 @@
+#include "builtin.h"
+#include "config.h"
+#include "dir.h"
+#include "lockfile.h"
+#include "parse-options.h"
+#include "commit-graph.h"
+
+static char const * const builtin_commit_graph_usage[] = {
+	N_("git commit-graph [--object-dir <objdir>]"),
+	N_("git commit-graph read [--object-dir <objdir>]"),
+	N_("git commit-graph write [--object-dir <objdir>] [--append] [--stdin-packs|--stdin-commits]"),
+	NULL
+};
+
+static const char * const builtin_commit_graph_read_usage[] = {
+	N_("git commit-graph read [--object-dir <objdir>]"),
+	NULL
+};
+
+static const char * const builtin_commit_graph_write_usage[] = {
+	N_("git commit-graph write [--object-dir <objdir>] [--append] [--stdin-packs|--stdin-commits]"),
+	NULL
+};
+
+static struct opts_commit_graph {
+	const char *obj_dir;
+	int stdin_packs;
+	int stdin_commits;
+	int append;
+} opts;
+
+static int graph_read(int argc, const char **argv)
+{
+	struct commit_graph *graph = NULL;
+	char *graph_name;
+
+	static struct option builtin_commit_graph_read_options[] = {
+		OPT_STRING(0, "object-dir", &opts.obj_dir,
+			N_("dir"),
+			N_("The object directory to store the graph")),
+		OPT_END(),
+	};
+
+	argc = parse_options(argc, argv, NULL,
+			     builtin_commit_graph_read_options,
+			     builtin_commit_graph_read_usage, 0);
+
+	if (!opts.obj_dir)
+		opts.obj_dir = get_object_directory();
+
+	graph_name = get_commit_graph_filename(opts.obj_dir);
+	graph = load_commit_graph_one(graph_name);
+
+	if (!graph)
+		die("graph file %s does not exist", graph_name);
+	FREE_AND_NULL(graph_name);
+
+	printf("header: %08x %d %d %d %d\n",
+		ntohl(*(uint32_t*)graph->data),
+		*(unsigned char*)(graph->data + 4),
+		*(unsigned char*)(graph->data + 5),
+		*(unsigned char*)(graph->data + 6),
+		*(unsigned char*)(graph->data + 7));
+	printf("num_commits: %u\n", graph->num_commits);
+	printf("chunks:");
+
+	if (graph->chunk_oid_fanout)
+		printf(" oid_fanout");
+	if (graph->chunk_oid_lookup)
+		printf(" oid_lookup");
+	if (graph->chunk_commit_data)
+		printf(" commit_metadata");
+	if (graph->chunk_large_edges)
+		printf(" large_edges");
+	printf("\n");
+
+	return 0;
+}
+
+static int graph_write(int argc, const char **argv)
+{
+	const char **pack_indexes = NULL;
+	int packs_nr = 0;
+	const char **commit_hex = NULL;
+	int commits_nr = 0;
+	const char **lines = NULL;
+	int lines_nr = 0;
+	int lines_alloc = 0;
+
+	static struct option builtin_commit_graph_write_options[] = {
+		OPT_STRING(0, "object-dir", &opts.obj_dir,
+			N_("dir"),
+			N_("The object directory to store the graph")),
+		OPT_BOOL(0, "stdin-packs", &opts.stdin_packs,
+			N_("scan pack-indexes listed by stdin for commits")),
+		OPT_BOOL(0, "stdin-commits", &opts.stdin_commits,
+			N_("start walk at commits listed by stdin")),
+		OPT_BOOL(0, "append", &opts.append,
+			N_("include all commits already in the commit-graph file")),
+		OPT_END(),
+	};
+
+	argc = parse_options(argc, argv, NULL,
+			     builtin_commit_graph_write_options,
+			     builtin_commit_graph_write_usage, 0);
+
+	if (opts.stdin_packs && opts.stdin_commits)
+		die(_("cannot use both --stdin-commits and --stdin-packs"));
+	if (!opts.obj_dir)
+		opts.obj_dir = get_object_directory();
+
+	if (opts.stdin_packs || opts.stdin_commits) {
+		struct strbuf buf = STRBUF_INIT;
+		lines_nr = 0;
+		lines_alloc = 128;
+		ALLOC_ARRAY(lines, lines_alloc);
+
+		while (strbuf_getline(&buf, stdin) != EOF) {
+			ALLOC_GROW(lines, lines_nr + 1, lines_alloc);
+			lines[lines_nr++] = strbuf_detach(&buf, NULL);
+		}
+
+		if (opts.stdin_packs) {
+			pack_indexes = lines;
+			packs_nr = lines_nr;
+		}
+		if (opts.stdin_commits) {
+			commit_hex = lines;
+			commits_nr = lines_nr;
+		}
+	}
+
+	write_commit_graph(opts.obj_dir,
+			   pack_indexes,
+			   packs_nr,
+			   commit_hex,
+			   commits_nr,
+			   opts.append);
+
+	return 0;
+}
+
+int cmd_commit_graph(int argc, const char **argv, const char *prefix)
+{
+	static struct option builtin_commit_graph_options[] = {
+		OPT_STRING(0, "object-dir", &opts.obj_dir,
+			N_("dir"),
+			N_("The object directory to store the graph")),
+		OPT_END(),
+	};
+
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage_with_options(builtin_commit_graph_usage,
+				   builtin_commit_graph_options);
+
+	git_config(git_default_config, NULL);
+	argc = parse_options(argc, argv, prefix,
+			     builtin_commit_graph_options,
+			     builtin_commit_graph_usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+
+	if (argc > 0) {
+		if (!strcmp(argv[0], "read"))
+			return graph_read(argc, argv);
+		if (!strcmp(argv[0], "write"))
+			return graph_write(argc, argv);
+	}
+
+	usage_with_options(builtin_commit_graph_usage,
+			   builtin_commit_graph_options);
+}
diff --git a/builtin/commit.c b/builtin/commit.c
index 5571d4a..a842fea 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -143,6 +143,16 @@
 	return 0;
 }
 
+static int opt_parse_rename_score(const struct option *opt, const char *arg, int unset)
+{
+	const char **value = opt->value;
+	if (arg != NULL && *arg == '=')
+		arg = arg + 1;
+
+	*value = arg;
+	return 0;
+}
+
 static void determine_whence(struct wt_status *s)
 {
 	if (file_exists(git_path_merge_head()))
@@ -161,9 +171,9 @@
 static void status_init_config(struct wt_status *s, config_fn_t fn)
 {
 	wt_status_prepare(s);
+	init_diff_ui_defaults();
 	git_config(fn, s);
 	determine_whence(s);
-	init_diff_ui_defaults();
 	s->hints = advice_status_hints; /* must come after git_config() */
 }
 
@@ -495,7 +505,7 @@
 static void assert_split_ident(struct ident_split *id, const struct strbuf *buf)
 {
 	if (split_ident_line(id, buf->buf, buf->len) || !id->date_begin)
-		die("BUG: unable to parse our own ident: %s", buf->buf);
+		BUG("unable to parse our own ident: %s", buf->buf);
 }
 
 static void export_one(const char *var, const char *s, const char *e, int hack)
@@ -1259,11 +1269,31 @@
 			return error(_("Invalid untracked files mode '%s'"), v);
 		return 0;
 	}
+	if (!strcmp(k, "diff.renamelimit")) {
+		if (s->rename_limit == -1)
+			s->rename_limit = git_config_int(k, v);
+		return 0;
+	}
+	if (!strcmp(k, "status.renamelimit")) {
+		s->rename_limit = git_config_int(k, v);
+		return 0;
+	}
+	if (!strcmp(k, "diff.renames")) {
+		if (s->detect_rename == -1)
+			s->detect_rename = git_config_rename(k, v);
+		return 0;
+	}
+	if (!strcmp(k, "status.renames")) {
+		s->detect_rename = git_config_rename(k, v);
+		return 0;
+	}
 	return git_diff_ui_config(k, v, NULL);
 }
 
 int cmd_status(int argc, const char **argv, const char *prefix)
 {
+	static int no_renames = -1;
+	static const char *rename_score_arg = (const char *)-1;
 	static struct wt_status s;
 	int fd;
 	struct object_id oid;
@@ -1297,6 +1327,10 @@
 		  N_("ignore changes to submodules, optional when: all, dirty, untracked. (Default: all)"),
 		  PARSE_OPT_OPTARG, NULL, (intptr_t)"all" },
 		OPT_COLUMN(0, "column", &s.colopts, N_("list untracked files in columns")),
+		OPT_BOOL(0, "no-renames", &no_renames, N_("do not detect renames")),
+		{ OPTION_CALLBACK, 'M', "find-renames", &rename_score_arg,
+		  N_("n"), N_("detect renames, optionally set similarity index"),
+		  PARSE_OPT_OPTARG, opt_parse_rename_score },
 		OPT_END(),
 	};
 
@@ -1336,6 +1370,14 @@
 	s.ignore_submodule_arg = ignore_submodule_arg;
 	s.status_format = status_format;
 	s.verbose = verbose;
+	if (no_renames != -1)
+		s.detect_rename = !no_renames;
+	if ((intptr_t)rename_score_arg != -1) {
+		if (s.detect_rename < DIFF_DETECT_RENAME)
+			s.detect_rename = DIFF_DETECT_RENAME;
+		if (rename_score_arg)
+			s.rename_score = parse_rename_score(&rename_score_arg);
+	}
 
 	wt_status_collect(&s);
 
diff --git a/builtin/config.c b/builtin/config.c
index 01169dd..b29d26d 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -25,7 +25,8 @@
 
 static int use_global_config, use_system_config, use_local_config;
 static struct git_config_source given_config_source;
-static int actions, types;
+static int actions, type;
+static char *default_value;
 static int end_null;
 static int respect_includes_opt = -1;
 static struct config_options config_options;
@@ -55,11 +56,68 @@
 #define PAGING_ACTIONS (ACTION_LIST | ACTION_GET_ALL | \
 			ACTION_GET_REGEXP | ACTION_GET_URLMATCH)
 
-#define TYPE_BOOL (1<<0)
-#define TYPE_INT (1<<1)
-#define TYPE_BOOL_OR_INT (1<<2)
-#define TYPE_PATH (1<<3)
-#define TYPE_EXPIRY_DATE (1<<4)
+#define TYPE_BOOL		1
+#define TYPE_INT		2
+#define TYPE_BOOL_OR_INT	3
+#define TYPE_PATH		4
+#define TYPE_EXPIRY_DATE	5
+#define TYPE_COLOR		6
+
+#define OPT_CALLBACK_VALUE(s, l, v, h, i) \
+	{ OPTION_CALLBACK, (s), (l), (v), NULL, (h), PARSE_OPT_NOARG | \
+	PARSE_OPT_NONEG, option_parse_type, (i) }
+
+static struct option builtin_config_options[];
+
+static int option_parse_type(const struct option *opt, const char *arg,
+			     int unset)
+{
+	int new_type, *to_type;
+
+	if (unset) {
+		*((int *) opt->value) = 0;
+		return 0;
+	}
+
+	/*
+	 * To support '--<type>' style flags, begin with new_type equal to
+	 * opt->defval.
+	 */
+	new_type = opt->defval;
+	if (!new_type) {
+		if (!strcmp(arg, "bool"))
+			new_type = TYPE_BOOL;
+		else if (!strcmp(arg, "int"))
+			new_type = TYPE_INT;
+		else if (!strcmp(arg, "bool-or-int"))
+			new_type = TYPE_BOOL_OR_INT;
+		else if (!strcmp(arg, "path"))
+			new_type = TYPE_PATH;
+		else if (!strcmp(arg, "expiry-date"))
+			new_type = TYPE_EXPIRY_DATE;
+		else if (!strcmp(arg, "color"))
+			new_type = TYPE_COLOR;
+		else
+			die(_("unrecognized --type argument, %s"), arg);
+	}
+
+	to_type = opt->value;
+	if (*to_type && *to_type != new_type) {
+		/*
+		 * Complain when there is a new type not equal to the old type.
+		 * This allows for combinations like '--int --type=int' and
+		 * '--type=int --type=int', but disallows ones like '--type=bool
+		 * --int' and '--type=bool
+		 * --type=int'.
+		 */
+		error("only one type at a time.");
+		usage_with_options(builtin_config_usage,
+			builtin_config_options);
+	}
+	*to_type = new_type;
+
+	return 0;
+}
 
 static struct option builtin_config_options[] = {
 	OPT_GROUP(N_("Config file location")),
@@ -84,16 +142,18 @@
 	OPT_BIT(0, "get-color", &actions, N_("find the color configured: slot [default]"), ACTION_GET_COLOR),
 	OPT_BIT(0, "get-colorbool", &actions, N_("find the color setting: slot [stdout-is-tty]"), ACTION_GET_COLORBOOL),
 	OPT_GROUP(N_("Type")),
-	OPT_BIT(0, "bool", &types, N_("value is \"true\" or \"false\""), TYPE_BOOL),
-	OPT_BIT(0, "int", &types, N_("value is decimal number"), TYPE_INT),
-	OPT_BIT(0, "bool-or-int", &types, N_("value is --bool or --int"), TYPE_BOOL_OR_INT),
-	OPT_BIT(0, "path", &types, N_("value is a path (file or directory name)"), TYPE_PATH),
-	OPT_BIT(0, "expiry-date", &types, N_("value is an expiry date"), TYPE_EXPIRY_DATE),
+	OPT_CALLBACK('t', "type", &type, "", N_("value is given this type"), option_parse_type),
+	OPT_CALLBACK_VALUE(0, "bool", &type, N_("value is \"true\" or \"false\""), TYPE_BOOL),
+	OPT_CALLBACK_VALUE(0, "int", &type, N_("value is decimal number"), TYPE_INT),
+	OPT_CALLBACK_VALUE(0, "bool-or-int", &type, N_("value is --bool or --int"), TYPE_BOOL_OR_INT),
+	OPT_CALLBACK_VALUE(0, "path", &type, N_("value is a path (file or directory name)"), TYPE_PATH),
+	OPT_CALLBACK_VALUE(0, "expiry-date", &type, N_("value is an expiry date"), TYPE_EXPIRY_DATE),
 	OPT_GROUP(N_("Other")),
 	OPT_BOOL('z', "null", &end_null, N_("terminate values with NUL byte")),
 	OPT_BOOL(0, "name-only", &omit_values, N_("show variable names only")),
 	OPT_BOOL(0, "includes", &respect_includes_opt, N_("respect include directives on lookup")),
 	OPT_BOOL(0, "show-origin", &show_origin, N_("show origin of config (file, standard input, blob, command line)")),
+	OPT_STRING(0, "default", &default_value, N_("value"), N_("with --get, use default value when missing entry")),
 	OPT_END(),
 };
 
@@ -149,30 +209,35 @@
 		if (show_keys)
 			strbuf_addch(buf, key_delim);
 
-		if (types == TYPE_INT)
+		if (type == TYPE_INT)
 			strbuf_addf(buf, "%"PRId64,
 				    git_config_int64(key_, value_ ? value_ : ""));
-		else if (types == TYPE_BOOL)
+		else if (type == TYPE_BOOL)
 			strbuf_addstr(buf, git_config_bool(key_, value_) ?
 				      "true" : "false");
-		else if (types == TYPE_BOOL_OR_INT) {
+		else if (type == TYPE_BOOL_OR_INT) {
 			int is_bool, v;
 			v = git_config_bool_or_int(key_, value_, &is_bool);
 			if (is_bool)
 				strbuf_addstr(buf, v ? "true" : "false");
 			else
 				strbuf_addf(buf, "%d", v);
-		} else if (types == TYPE_PATH) {
+		} else if (type == TYPE_PATH) {
 			const char *v;
 			if (git_config_pathname(&v, key_, value_) < 0)
 				return -1;
 			strbuf_addstr(buf, v);
 			free((char *)v);
-		} else if (types == TYPE_EXPIRY_DATE) {
+		} else if (type == TYPE_EXPIRY_DATE) {
 			timestamp_t t;
 			if (git_config_expiry_date(&t, key_, value_) < 0)
 				return -1;
 			strbuf_addf(buf, "%"PRItime, t);
+		} else if (type == TYPE_COLOR) {
+			char v[COLOR_MAXLEN];
+			if (git_config_color(v, key_, value_) < 0)
+				return -1;
+			strbuf_addstr(buf, v);
 		} else if (value_) {
 			strbuf_addstr(buf, value_);
 		} else {
@@ -258,6 +323,16 @@
 	config_with_options(collect_config, &values,
 			    &given_config_source, &config_options);
 
+	if (!values.nr && default_value) {
+		struct strbuf *item;
+		ALLOC_GROW(values.items, values.nr + 1, values.alloc);
+		item = &values.items[values.nr++];
+		strbuf_init(item, 0);
+		if (format_config(item, key_, default_value) < 0)
+			die(_("failed to format default config value: %s"),
+				default_value);
+	}
+
 	ret = !values.nr;
 
 	for (i = 0; i < values.nr; i++) {
@@ -287,7 +362,7 @@
 	if (!value)
 		return NULL;
 
-	if (types == 0 || types == TYPE_PATH || types == TYPE_EXPIRY_DATE)
+	if (type == 0 || type == TYPE_PATH || type == TYPE_EXPIRY_DATE)
 		/*
 		 * We don't do normalization for TYPE_PATH here: If
 		 * the path is like ~/foobar/, we prefer to store
@@ -296,11 +371,11 @@
 		 * Also don't do normalization for expiry dates.
 		 */
 		return xstrdup(value);
-	if (types == TYPE_INT)
+	if (type == TYPE_INT)
 		return xstrfmt("%"PRId64, git_config_int64(key, value));
-	if (types == TYPE_BOOL)
+	if (type == TYPE_BOOL)
 		return xstrdup(git_config_bool(key, value) ?  "true" : "false");
-	if (types == TYPE_BOOL_OR_INT) {
+	if (type == TYPE_BOOL_OR_INT) {
 		int is_bool, v;
 		v = git_config_bool_or_int(key, value, &is_bool);
 		if (!is_bool)
@@ -308,8 +383,22 @@
 		else
 			return xstrdup(v ? "true" : "false");
 	}
+	if (type == TYPE_COLOR) {
+		char v[COLOR_MAXLEN];
+		if (git_config_color(v, key, value))
+			die("cannot parse color '%s'", value);
 
-	die("BUG: cannot normalize type %d", types);
+		/*
+		 * The contents of `v` now contain an ANSI escape
+		 * sequence, not suitable for including within a
+		 * configuration file. Treat the above as a
+		 * "sanity-check", and return the given value, which we
+		 * know is representable as valid color code.
+		 */
+		return xstrdup(value);
+	}
+
+	BUG("cannot normalize type %d", type);
 }
 
 static int get_color_found;
@@ -513,6 +602,9 @@
 	if (use_local_config && nongit)
 		die(_("--local can only be used inside a git repository"));
 
+	if (given_config_source.blob && nongit)
+		die(_("--blob can only be used inside a git repository"));
+
 	if (given_config_source.file &&
 			!strcmp(given_config_source.file, "-")) {
 		given_config_source.file = NULL;
@@ -566,12 +658,7 @@
 		key_delim = '\n';
 	}
 
-	if (HAS_MULTI_BITS(types)) {
-		error("only one type at a time.");
-		usage_with_options(builtin_config_usage, builtin_config_options);
-	}
-
-	if ((actions & (ACTION_GET_COLOR|ACTION_GET_COLORBOOL)) && types) {
+	if ((actions & (ACTION_GET_COLOR|ACTION_GET_COLORBOOL)) && type) {
 		error("--get-color and variable type are incoherent");
 		usage_with_options(builtin_config_usage, builtin_config_options);
 	}
@@ -601,6 +688,12 @@
 		usage_with_options(builtin_config_usage, builtin_config_options);
 	}
 
+	if (default_value && !(actions & ACTION_GET)) {
+		error("--default is only applicable to --get");
+		usage_with_options(builtin_config_usage,
+			builtin_config_options);
+	}
+
 	if (actions & PAGING_ACTIONS)
 		setup_auto_pager("config", 1);
 
diff --git a/builtin/count-objects.c b/builtin/count-objects.c
index b054713..d51e2ce 100644
--- a/builtin/count-objects.c
+++ b/builtin/count-objects.c
@@ -66,7 +66,7 @@
 	else {
 		loose_size += on_disk_bytes(st);
 		loose++;
-		if (verbose && has_sha1_pack(oid->hash))
+		if (verbose && has_object_pack(oid))
 			packed_loose++;
 	}
 	return 0;
diff --git a/builtin/describe.c b/builtin/describe.c
index b5afc45..cf1ae77 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -502,7 +502,7 @@
 
 	if (cmit)
 		describe_commit(&oid, &sb);
-	else if (oid_object_info(&oid, NULL) == OBJ_BLOB)
+	else if (oid_object_info(the_repository, &oid, NULL) == OBJ_BLOB)
 		describe_blob(oid, &sb);
 	else
 		die(_("%s is neither a commit nor blob"), arg);
@@ -612,7 +612,7 @@
 				suffix = broken;
 			}
 		} else if (dirty) {
-			static struct lock_file index_lock;
+			struct lock_file index_lock = LOCK_INIT;
 			struct rev_info revs;
 			struct argv_array args = ARGV_ARRAY_INIT;
 			int fd, result;
diff --git a/builtin/diff.c b/builtin/diff.c
index 16bfb22..bfefff3 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -398,7 +398,7 @@
 		if (!obj)
 			die(_("invalid object '%s' given."), name);
 		if (obj->type == OBJ_COMMIT)
-			obj = &((struct commit *)obj)->tree->object;
+			obj = &get_commit_tree(((struct commit *)obj))->object;
 
 		if (obj->type == OBJ_TREE) {
 			obj->flags |= flags;
diff --git a/builtin/difftool.c b/builtin/difftool.c
index aad0e07..bc97d4a 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -610,7 +610,7 @@
 			continue;
 
 		if (!indices_loaded) {
-			static struct lock_file lock;
+			struct lock_file lock = LOCK_INIT;
 			strbuf_reset(&buf);
 			strbuf_addf(&buf, "%s/wtindex", tmpdir);
 			if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
@@ -695,12 +695,11 @@
 			 N_("use `diff.guitool` instead of `diff.tool`")),
 		OPT_BOOL('d', "dir-diff", &dir_diff,
 			 N_("perform a full-directory diff")),
-		{ OPTION_SET_INT, 'y', "no-prompt", &prompt, NULL,
+		OPT_SET_INT_F('y', "no-prompt", &prompt,
 			N_("do not prompt before launching a diff tool"),
-			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
-		{ OPTION_SET_INT, 0, "prompt", &prompt, NULL, NULL,
-			PARSE_OPT_NOARG | PARSE_OPT_NONEG | PARSE_OPT_HIDDEN,
-			NULL, 1 },
+			0, PARSE_OPT_NONEG),
+		OPT_SET_INT_F(0, "prompt", &prompt, NULL,
+			1, PARSE_OPT_NONEG | PARSE_OPT_HIDDEN),
 		OPT_BOOL(0, "symlinks", &symlinks,
 			 N_("use symlinks in dir-diff mode")),
 		OPT_STRING('t', "tool", &difftool_cmd, N_("<tool>"),
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index a15898d..6c97687 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -7,6 +7,7 @@
 #include "cache.h"
 #include "config.h"
 #include "refs.h"
+#include "refspec.h"
 #include "commit.h"
 #include "object.h"
 #include "tag.h"
@@ -35,8 +36,7 @@
 static int no_data;
 static int full_tree;
 static struct string_list extra_refs = STRING_LIST_INIT_NODUP;
-static struct refspec *refspecs;
-static int refspecs_nr;
+static struct refspec refspecs = REFSPEC_INIT_FETCH;
 static int anonymize;
 
 static int parse_opt_signed_tag_mode(const struct option *opt,
@@ -156,15 +156,14 @@
 	}
 }
 
-/* Since intptr_t is C99, we do not use it here */
-static inline uint32_t *mark_to_ptr(uint32_t mark)
+static inline void *mark_to_ptr(uint32_t mark)
 {
-	return ((uint32_t *)NULL) + mark;
+	return (void *)(uintptr_t)mark;
 }
 
 static inline uint32_t ptr_to_mark(void * mark)
 {
-	return (uint32_t *)mark - (uint32_t *)NULL;
+	return (uint32_t)(uintptr_t)mark;
 }
 
 static inline void mark_object(struct object *object, uint32_t mark)
@@ -517,7 +516,7 @@
 	/* skip "committer", "author", "tagger", etc */
 	end_of_header = strchr(*beg, ' ');
 	if (!end_of_header)
-		die("BUG: malformed line fed to anonymize_ident_line: %.*s",
+		BUG("malformed line fed to anonymize_ident_line: %.*s",
 		    (int)(*end - *beg), *beg);
 	end_of_header++;
 	strbuf_add(out, *beg, end_of_header - *beg);
@@ -578,11 +577,11 @@
 	    get_object_mark(&commit->parents->item->object) != 0 &&
 	    !full_tree) {
 		parse_commit_or_die(commit->parents->item);
-		diff_tree_oid(&commit->parents->item->tree->object.oid,
-			      &commit->tree->object.oid, "", &rev->diffopt);
+		diff_tree_oid(get_commit_tree_oid(commit->parents->item),
+			      get_commit_tree_oid(commit), "", &rev->diffopt);
 	}
 	else
-		diff_root_tree_oid(&commit->tree->object.oid,
+		diff_root_tree_oid(get_commit_tree_oid(commit),
 				   "", &rev->diffopt);
 
 	/* Export the referenced blobs, and remember the marks. */
@@ -651,8 +650,11 @@
 	struct commit *commit;
 	while (commits->nr) {
 		commit = (struct commit *)object_array_pop(commits);
-		if (has_unshown_parent(commit))
+		if (has_unshown_parent(commit)) {
+			/* Queue again, to be handled later */
+			add_object_array(&commit->object, NULL, commits);
 			return;
+		}
 		handle_commit(commit, revs, paths_of_changed_objects);
 	}
 }
@@ -826,9 +828,9 @@
 		if (dwim_ref(e->name, strlen(e->name), &oid, &full_name) != 1)
 			continue;
 
-		if (refspecs) {
+		if (refspecs.nr) {
 			char *private;
-			private = apply_refspecs(refspecs, refspecs_nr, full_name);
+			private = apply_refspecs(&refspecs, full_name);
 			if (private) {
 				free(full_name);
 				full_name = private;
@@ -947,7 +949,7 @@
 		if (last_idnum < mark)
 			last_idnum = mark;
 
-		type = oid_object_info(&oid, NULL);
+		type = oid_object_info(the_repository, &oid, NULL);
 		if (type < 0)
 			die("object not found: %s", oid_to_hex(&oid));
 
@@ -974,8 +976,8 @@
 static void handle_deletes(void)
 {
 	int i;
-	for (i = 0; i < refspecs_nr; i++) {
-		struct refspec *refspec = &refspecs[i];
+	for (i = 0; i < refspecs.nr; i++) {
+		struct refspec_item *refspec = &refspecs.items[i];
 		if (*refspec->src)
 			continue;
 
@@ -1036,18 +1038,12 @@
 		usage_with_options (fast_export_usage, options);
 
 	if (refspecs_list.nr) {
-		const char **refspecs_str;
 		int i;
 
-		ALLOC_ARRAY(refspecs_str, refspecs_list.nr);
 		for (i = 0; i < refspecs_list.nr; i++)
-			refspecs_str[i] = refspecs_list.items[i].string;
-
-		refspecs_nr = refspecs_list.nr;
-		refspecs = parse_fetch_refspec(refspecs_nr, refspecs_str);
+			refspec_append(&refspecs, refspecs_list.items[i].string);
 
 		string_list_clear(&refspecs_list, 1);
-		free(refspecs_str);
 	}
 
 	if (use_done_feature)
@@ -1086,7 +1082,7 @@
 	if (use_done_feature)
 		printf("done\n");
 
-	free_refspec(refspecs_nr, refspecs);
+	refspec_clear(&refspecs);
 
 	return 0;
 }
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index a7bc136..1a1bc63 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -4,6 +4,7 @@
 #include "remote.h"
 #include "connect.h"
 #include "sha1-array.h"
+#include "protocol.h"
 
 static const char fetch_pack_usage[] =
 "git fetch-pack [--all] [--stdin] [--quiet | -q] [--keep | -k] [--thin] "
@@ -52,6 +53,7 @@
 	struct fetch_pack_args args;
 	struct oid_array shallow = OID_ARRAY_INIT;
 	struct string_list deepen_not = STRING_LIST_INIT_DUP;
+	struct packet_reader reader;
 
 	fetch_if_missing = 0;
 
@@ -211,10 +213,24 @@
 		if (!conn)
 			return args.diag_url ? 0 : 1;
 	}
-	get_remote_heads(fd[0], NULL, 0, &ref, 0, NULL, &shallow);
+
+	packet_reader_init(&reader, fd[0], NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_GENTLE_ON_EOF);
+
+	switch (discover_version(&reader)) {
+	case protocol_v2:
+		die("support for protocol v2 not implemented yet");
+	case protocol_v1:
+	case protocol_v0:
+		get_remote_heads(&reader, &ref, 0, NULL, &shallow);
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
+	}
 
 	ref = fetch_pack(&args, fd, conn, ref, dest, sought, nr_sought,
-			 &shallow, pack_lockfile_ptr);
+			 &shallow, pack_lockfile_ptr, protocol_v0);
 	if (pack_lockfile) {
 		printf("lock %s\n", pack_lockfile);
 		fflush(stdout);
diff --git a/builtin/fetch.c b/builtin/fetch.c
index dcdfc66..ea5b966 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -5,6 +5,7 @@
 #include "config.h"
 #include "repository.h"
 #include "refs.h"
+#include "refspec.h"
 #include "commit.h"
 #include "builtin.h"
 #include "string-list.h"
@@ -59,9 +60,9 @@
 static int recurse_submodules = RECURSE_SUBMODULES_DEFAULT;
 static int recurse_submodules_default = RECURSE_SUBMODULES_ON_DEMAND;
 static int shown_url = 0;
-static int refmap_alloc, refmap_nr;
-static const char **refmap_array;
+static struct refspec refmap = REFSPEC_INIT_FETCH;
 static struct list_objects_filter_options filter_options;
+static struct string_list server_options = STRING_LIST_INIT_DUP;
 
 static int git_fetch_config(const char *k, const char *v, void *cb)
 {
@@ -107,14 +108,12 @@
 
 static int parse_refmap_arg(const struct option *opt, const char *arg, int unset)
 {
-	ALLOC_GROW(refmap_array, refmap_nr + 1, refmap_alloc);
-
 	/*
 	 * "git fetch --refmap='' origin foo"
 	 * can be used to tell the command not to store anywhere
 	 */
-	if (*arg)
-		refmap_array[refmap_nr++] = arg;
+	refspec_append(&refmap, arg);
+
 	return 0;
 }
 
@@ -156,9 +155,9 @@
 			N_("deepen history of shallow clone, excluding rev")),
 	OPT_INTEGER(0, "deepen", &deepen_relative,
 		    N_("deepen history of shallow clone")),
-	{ OPTION_SET_INT, 0, "unshallow", &unshallow, NULL,
-		   N_("convert to a complete repository"),
-		   PARSE_OPT_NONEG | PARSE_OPT_NOARG, NULL, 1 },
+	OPT_SET_INT_F(0, "unshallow", &unshallow,
+		      N_("convert to a complete repository"),
+		      1, PARSE_OPT_NONEG),
 	{ OPTION_STRING, 0, "submodule-prefix", &submodule_prefix, N_("dir"),
 		   N_("prepend this to submodule path output"), PARSE_OPT_HIDDEN },
 	{ OPTION_CALLBACK, 0, "recurse-submodules-default",
@@ -170,6 +169,7 @@
 		 N_("accept refs that update .git/shallow")),
 	{ OPTION_CALLBACK, 0, "refmap", NULL, N_("refmap"),
 	  N_("specify fetch refmap"), PARSE_OPT_NONEG, parse_refmap_arg },
+	OPT_STRING_LIST('o', "server-option", &server_options, N_("server-specific"), N_("option to transmit")),
 	OPT_SET_INT('4', "ipv4", &family, N_("use IPv4 addresses only"),
 			TRANSPORT_FAMILY_IPV4),
 	OPT_SET_INT('6', "ipv6", &family, N_("use IPv6 addresses only"),
@@ -202,7 +202,7 @@
 
 	for (i = 0; i < branch->merge_nr; i++) {
 		struct ref *rm, **old_tail = *tail;
-		struct refspec refspec;
+		struct refspec_item refspec;
 
 		for (rm = *head; rm; rm = rm->next) {
 			if (branch_merge_matches(branch, i, rm->name)) {
@@ -264,7 +264,7 @@
 	struct string_list_item *item = NULL;
 
 	for_each_ref(add_existing, &existing_refs);
-	for (ref = transport_get_remote_refs(transport); ref; ref = ref->next) {
+	for (ref = transport_get_remote_refs(transport, NULL); ref; ref = ref->next) {
 		if (!starts_with(ref->name, "refs/tags/"))
 			continue;
 
@@ -339,26 +339,40 @@
 }
 
 static struct ref *get_ref_map(struct transport *transport,
-			       struct refspec *refspecs, int refspec_count,
+			       struct refspec *rs,
 			       int tags, int *autotags)
 {
 	int i;
 	struct ref *rm;
 	struct ref *ref_map = NULL;
 	struct ref **tail = &ref_map;
+	struct argv_array ref_prefixes = ARGV_ARRAY_INIT;
 
 	/* opportunistically-updated references: */
 	struct ref *orefs = NULL, **oref_tail = &orefs;
 
-	const struct ref *remote_refs = transport_get_remote_refs(transport);
+	const struct ref *remote_refs;
 
-	if (refspec_count) {
+	if (rs->nr)
+		refspec_ref_prefixes(rs, &ref_prefixes);
+	else if (transport->remote && transport->remote->fetch.nr)
+		refspec_ref_prefixes(&transport->remote->fetch, &ref_prefixes);
+
+	if (ref_prefixes.argc &&
+	    (tags == TAGS_SET || (tags == TAGS_DEFAULT && !rs->nr))) {
+		argv_array_push(&ref_prefixes, "refs/tags/");
+	}
+
+	remote_refs = transport_get_remote_refs(transport, &ref_prefixes);
+
+	argv_array_clear(&ref_prefixes);
+
+	if (rs->nr) {
 		struct refspec *fetch_refspec;
-		int fetch_refspec_nr;
 
-		for (i = 0; i < refspec_count; i++) {
-			get_fetch_map(remote_refs, &refspecs[i], &tail, 0);
-			if (refspecs[i].dst && refspecs[i].dst[0])
+		for (i = 0; i < rs->nr; i++) {
+			get_fetch_map(remote_refs, &rs->items[i], &tail, 0);
+			if (rs->items[i].dst && rs->items[i].dst[0])
 				*autotags = 1;
 		}
 		/* Merge everything on the command line (but not --tags) */
@@ -385,17 +399,14 @@
 		 * by ref_remove_duplicates() in favor of one of these
 		 * opportunistic entries with FETCH_HEAD_IGNORE.
 		 */
-		if (refmap_array) {
-			fetch_refspec = parse_fetch_refspec(refmap_nr, refmap_array);
-			fetch_refspec_nr = refmap_nr;
-		} else {
-			fetch_refspec = transport->remote->fetch;
-			fetch_refspec_nr = transport->remote->fetch_refspec_nr;
-		}
+		if (refmap.nr)
+			fetch_refspec = &refmap;
+		else
+			fetch_refspec = &transport->remote->fetch;
 
-		for (i = 0; i < fetch_refspec_nr; i++)
-			get_fetch_map(ref_map, &fetch_refspec[i], &oref_tail, 1);
-	} else if (refmap_array) {
+		for (i = 0; i < fetch_refspec->nr; i++)
+			get_fetch_map(ref_map, &fetch_refspec->items[i], &oref_tail, 1);
+	} else if (refmap.nr) {
 		die("--refmap option is only meaningful with command-line refspec(s).");
 	} else {
 		/* Use the defaults */
@@ -403,16 +414,16 @@
 		struct branch *branch = branch_get(NULL);
 		int has_merge = branch_has_merge_config(branch);
 		if (remote &&
-		    (remote->fetch_refspec_nr ||
+		    (remote->fetch.nr ||
 		     /* Note: has_merge implies non-NULL branch->remote_name */
 		     (has_merge && !strcmp(branch->remote_name, remote->name)))) {
-			for (i = 0; i < remote->fetch_refspec_nr; i++) {
-				get_fetch_map(remote_refs, &remote->fetch[i], &tail, 0);
-				if (remote->fetch[i].dst &&
-				    remote->fetch[i].dst[0])
+			for (i = 0; i < remote->fetch.nr; i++) {
+				get_fetch_map(remote_refs, &remote->fetch.items[i], &tail, 0);
+				if (remote->fetch.items[i].dst &&
+				    remote->fetch.items[i].dst[0])
 					*autotags = 1;
 				if (!i && !has_merge && ref_map &&
-				    !remote->fetch[0].pattern)
+				    !remote->fetch.items[0].pattern)
 					ref_map->fetch_head_status = FETCH_HEAD_MERGE;
 			}
 			/*
@@ -637,7 +648,7 @@
 	struct branch *current_branch = branch_get(NULL);
 	const char *pretty_ref = prettify_refname(ref->name);
 
-	type = oid_object_info(&ref->new_oid, NULL);
+	type = oid_object_info(the_repository, &ref->new_oid, NULL);
 	if (type < 0)
 		die(_("object %s not found"), oid_to_hex(&ref->new_oid));
 
@@ -947,11 +958,11 @@
 	return ret;
 }
 
-static int prune_refs(struct refspec *refs, int ref_count, struct ref *ref_map,
-		const char *raw_url)
+static int prune_refs(struct refspec *rs, struct ref *ref_map,
+		      const char *raw_url)
 {
 	int url_len, i, result = 0;
-	struct ref *ref, *stale_refs = get_stale_heads(refs, ref_count, ref_map);
+	struct ref *ref, *stale_refs = get_stale_heads(rs, ref_map);
 	char *url;
 	int summary_width = transport_summary_width(stale_refs);
 	const char *dangling_msg = dry_run
@@ -1097,7 +1108,7 @@
 }
 
 static int do_fetch(struct transport *transport,
-		    struct refspec *refs, int ref_count)
+		    struct refspec *rs)
 {
 	struct string_list existing_refs = STRING_LIST_INIT_DUP;
 	struct ref *ref_map;
@@ -1121,7 +1132,7 @@
 			goto cleanup;
 	}
 
-	ref_map = get_ref_map(transport, refs, ref_count, tags, &autotags);
+	ref_map = get_ref_map(transport, rs, tags, &autotags);
 	if (!update_head_ok)
 		check_not_current_branch(ref_map);
 
@@ -1145,11 +1156,10 @@
 		 * explicitly (via command line or configuration); we
 		 * don't care whether --tags was specified.
 		 */
-		if (ref_count) {
-			prune_refs(refs, ref_count, ref_map, transport->url);
+		if (rs->nr) {
+			prune_refs(rs, ref_map, transport->url);
 		} else {
-			prune_refs(transport->remote->fetch,
-				   transport->remote->fetch_refspec_nr,
+			prune_refs(&transport->remote->fetch,
 				   ref_map,
 				   transport->url);
 		}
@@ -1338,10 +1348,8 @@
 
 static int fetch_one(struct remote *remote, int argc, const char **argv, int prune_tags_ok)
 {
-	static const char **refs = NULL;
-	struct refspec *refspec;
-	int ref_nr = 0;
-	int j = 0;
+	struct refspec rs = REFSPEC_INIT_FETCH;
+	int i;
 	int exit_code;
 	int maybe_prune_tags;
 	int remote_via_config = remote_is_configured(remote, 0);
@@ -1374,37 +1382,34 @@
 
 	maybe_prune_tags = prune_tags_ok && prune_tags;
 	if (maybe_prune_tags && remote_via_config)
-		add_prune_tags_to_fetch_refspec(remote);
+		refspec_append(&remote->fetch, TAG_REFSPEC);
 
-	if (argc > 0 || (maybe_prune_tags && !remote_via_config)) {
-		size_t nr_alloc = st_add3(argc, maybe_prune_tags, 1);
-		refs = xcalloc(nr_alloc, sizeof(const char *));
-		if (maybe_prune_tags) {
-			refs[j++] = xstrdup("refs/tags/*:refs/tags/*");
-			ref_nr++;
+	if (maybe_prune_tags && (argc || !remote_via_config))
+		refspec_append(&rs, TAG_REFSPEC);
+
+	for (i = 0; i < argc; i++) {
+		if (!strcmp(argv[i], "tag")) {
+			char *tag;
+			i++;
+			if (i >= argc)
+				die(_("You need to specify a tag name."));
+
+			tag = xstrfmt("refs/tags/%s:refs/tags/%s",
+				      argv[i], argv[i]);
+			refspec_append(&rs, tag);
+			free(tag);
+		} else {
+			refspec_append(&rs, argv[i]);
 		}
 	}
 
-	if (argc > 0) {
-		int i;
-		for (i = 0; i < argc; i++) {
-			if (!strcmp(argv[i], "tag")) {
-				i++;
-				if (i >= argc)
-					die(_("You need to specify a tag name."));
-				refs[j++] = xstrfmt("refs/tags/%s:refs/tags/%s",
-						    argv[i], argv[i]);
-			} else
-				refs[j++] = argv[i];
-			ref_nr++;
-		}
-	}
+	if (server_options.nr)
+		gtransport->server_options = &server_options;
 
 	sigchain_push_common(unlock_pack_on_signal);
 	atexit(unlock_pack);
-	refspec = parse_fetch_refspec(ref_nr, refs);
-	exit_code = do_fetch(gtransport, refspec, ref_nr);
-	free_refspec(ref_nr, refspec);
+	exit_code = do_fetch(gtransport, &rs);
+	refspec_clear(&rs);
 	transport_disconnect(gtransport);
 	gtransport = NULL;
 	return exit_code;
diff --git a/builtin/fsck.c b/builtin/fsck.c
index 087360a..3ad4f16 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -67,7 +67,8 @@
 	const char *ret;
 
 	if (obj->type == OBJ_NONE) {
-		enum object_type type = oid_object_info(&obj->oid, NULL);
+		enum object_type type = oid_object_info(the_repository,
+							&obj->oid, NULL);
 		if (type > 0)
 			object_as_type(obj, type, 0);
 	}
@@ -227,7 +228,7 @@
 	if (!(obj->flags & HAS_OBJ)) {
 		if (is_promisor_object(&obj->oid))
 			return;
-		if (has_sha1_pack(obj->oid.hash))
+		if (has_object_pack(&obj->oid))
 			return; /* it is in pack - forget about it */
 		printf("missing %s %s\n", printable_type(obj),
 			describe_object(obj));
@@ -339,7 +340,7 @@
 	}
 }
 
-static int fsck_obj(struct object *obj)
+static int fsck_obj(struct object *obj, void *buffer, unsigned long size)
 {
 	int err;
 
@@ -353,7 +354,7 @@
 
 	if (fsck_walk(obj, NULL, &fsck_obj_options))
 		objerror(obj, "broken links");
-	err = fsck_object(obj, NULL, 0, &fsck_obj_options);
+	err = fsck_object(obj, buffer, size, &fsck_obj_options);
 	if (err)
 		goto out;
 
@@ -398,7 +399,7 @@
 	}
 	obj->flags &= ~(REACHABLE | SEEN);
 	obj->flags |= HAS_OBJ;
-	return fsck_obj(obj);
+	return fsck_obj(obj, buffer, size);
 }
 
 static int default_refs;
@@ -506,44 +507,42 @@
 	}
 }
 
-static struct object *parse_loose_object(const struct object_id *oid,
-					 const char *path)
-{
-	struct object *obj;
-	void *contents;
-	enum object_type type;
-	unsigned long size;
-	int eaten;
-
-	if (read_loose_object(path, oid, &type, &size, &contents) < 0)
-		return NULL;
-
-	if (!contents && type != OBJ_BLOB)
-		die("BUG: read_loose_object streamed a non-blob");
-
-	obj = parse_object_buffer(oid, type, size, contents, &eaten);
-
-	if (!eaten)
-		free(contents);
-	return obj;
-}
-
 static int fsck_loose(const struct object_id *oid, const char *path, void *data)
 {
-	struct object *obj = parse_loose_object(oid, path);
+	struct object *obj;
+	enum object_type type;
+	unsigned long size;
+	void *contents;
+	int eaten;
 
-	if (!obj) {
+	if (read_loose_object(path, oid, &type, &size, &contents) < 0) {
 		errors_found |= ERROR_OBJECT;
 		error("%s: object corrupt or missing: %s",
 		      oid_to_hex(oid), path);
 		return 0; /* keep checking other objects */
 	}
 
+	if (!contents && type != OBJ_BLOB)
+		BUG("read_loose_object streamed a non-blob");
+
+	obj = parse_object_buffer(oid, type, size, contents, &eaten);
+	if (!obj) {
+		errors_found |= ERROR_OBJECT;
+		error("%s: object could not be parsed: %s",
+		      oid_to_hex(oid), path);
+		if (!eaten)
+			free(contents);
+		return 0; /* keep checking other objects */
+	}
+
 	obj->flags &= ~(REACHABLE | SEEN);
 	obj->flags |= HAS_OBJ;
-	if (fsck_obj(obj))
+	if (fsck_obj(obj, contents, size))
 		errors_found |= ERROR_OBJECT;
-	return 0;
+
+	if (!eaten)
+		free(contents);
+	return 0; /* keep checking other objects, even if we saw an error */
 }
 
 static int fsck_cruft(const char *basename, const char *path, void *data)
@@ -755,6 +754,9 @@
 			}
 			stop_progress(&progress);
 		}
+
+		if (fsck_finish(&fsck_obj_options))
+			errors_found |= ERROR_OBJECT;
 	}
 
 	for (i = 0; i < argc; i++) {
diff --git a/builtin/gc.c b/builtin/gc.c
index 3e67124..ccfb1ce 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -22,6 +22,10 @@
 #include "commit.h"
 #include "packfile.h"
 #include "object-store.h"
+#include "pack.h"
+#include "pack-objects.h"
+#include "blob.h"
+#include "tree.h"
 
 #define FAILED_RUN "failed to run %s"
 
@@ -41,6 +45,8 @@
 static const char *gc_log_expire = "1.day.ago";
 static const char *prune_expire = "2.weeks.ago";
 static const char *prune_worktrees_expire = "3.months.ago";
+static unsigned long big_pack_threshold;
+static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE;
 
 static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
 static struct argv_array reflog = ARGV_ARRAY_INIT;
@@ -128,6 +134,9 @@
 	git_config_get_expiry("gc.worktreepruneexpire", &prune_worktrees_expire);
 	git_config_get_expiry("gc.logexpiry", &gc_log_expire);
 
+	git_config_get_ulong("gc.bigpackthreshold", &big_pack_threshold);
+	git_config_get_ulong("pack.deltacachesize", &max_delta_cache_size);
+
 	git_config(git_default_config, NULL);
 }
 
@@ -166,6 +175,28 @@
 	return needed;
 }
 
+static struct packed_git *find_base_packs(struct string_list *packs,
+					  unsigned long limit)
+{
+	struct packed_git *p, *base = NULL;
+
+	for (p = get_packed_git(the_repository); p; p = p->next) {
+		if (!p->pack_local)
+			continue;
+		if (limit) {
+			if (p->pack_size >= limit)
+				string_list_append(packs, p->pack_name);
+		} else if (!base || base->pack_size < p->pack_size) {
+			base = p;
+		}
+	}
+
+	if (base)
+		string_list_append(packs, base->pack_name);
+
+	return base;
+}
+
 static int too_many_packs(void)
 {
 	struct packed_git *p;
@@ -188,7 +219,86 @@
 	return gc_auto_pack_limit < cnt;
 }
 
-static void add_repack_all_option(void)
+static uint64_t total_ram(void)
+{
+#if defined(HAVE_SYSINFO)
+	struct sysinfo si;
+
+	if (!sysinfo(&si))
+		return si.totalram;
+#elif defined(HAVE_BSD_SYSCTL) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM))
+	int64_t physical_memory;
+	int mib[2];
+	size_t length;
+
+	mib[0] = CTL_HW;
+# if defined(HW_MEMSIZE)
+	mib[1] = HW_MEMSIZE;
+# else
+	mib[1] = HW_PHYSMEM;
+# endif
+	length = sizeof(int64_t);
+	if (!sysctl(mib, 2, &physical_memory, &length, NULL, 0))
+		return physical_memory;
+#elif defined(GIT_WINDOWS_NATIVE)
+	MEMORYSTATUSEX memInfo;
+
+	memInfo.dwLength = sizeof(MEMORYSTATUSEX);
+	if (GlobalMemoryStatusEx(&memInfo))
+		return memInfo.ullTotalPhys;
+#endif
+	return 0;
+}
+
+static uint64_t estimate_repack_memory(struct packed_git *pack)
+{
+	unsigned long nr_objects = approximate_object_count();
+	size_t os_cache, heap;
+
+	if (!pack || !nr_objects)
+		return 0;
+
+	/*
+	 * First we have to scan through at least one pack.
+	 * Assume enough room in OS file cache to keep the entire pack
+	 * or we may accidentally evict data of other processes from
+	 * the cache.
+	 */
+	os_cache = pack->pack_size + pack->index_size;
+	/* then pack-objects needs lots more for book keeping */
+	heap = sizeof(struct object_entry) * nr_objects;
+	/*
+	 * internal rev-list --all --objects takes up some memory too,
+	 * let's say half of it is for blobs
+	 */
+	heap += sizeof(struct blob) * nr_objects / 2;
+	/*
+	 * and the other half is for trees (commits and tags are
+	 * usually insignificant)
+	 */
+	heap += sizeof(struct tree) * nr_objects / 2;
+	/* and then obj_hash[], underestimated in fact */
+	heap += sizeof(struct object *) * nr_objects;
+	/* revindex is used also */
+	heap += sizeof(struct revindex_entry) * nr_objects;
+	/*
+	 * read_sha1_file() (either at delta calculation phase, or
+	 * writing phase) also fills up the delta base cache
+	 */
+	heap += delta_base_cache_limit;
+	/* and of course pack-objects has its own delta cache */
+	heap += max_delta_cache_size;
+
+	return os_cache + heap;
+}
+
+static int keep_one_pack(struct string_list_item *item, void *data)
+{
+	argv_array_pushf(&repack, "--keep-pack=%s", basename(item->string));
+	return 0;
+}
+
+static void add_repack_all_option(struct string_list *keep_pack)
 {
 	if (prune_expire && !strcmp(prune_expire, "now"))
 		argv_array_push(&repack, "-a");
@@ -197,6 +307,9 @@
 		if (prune_expire)
 			argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 	}
+
+	if (keep_pack)
+		for_each_string_list(keep_pack, keep_one_pack, NULL);
 }
 
 static void add_repack_incremental_option(void)
@@ -219,9 +332,35 @@
 	 * we run "repack -A -d -l".  Otherwise we tell the caller
 	 * there is no need.
 	 */
-	if (too_many_packs())
-		add_repack_all_option();
-	else if (too_many_loose_objects())
+	if (too_many_packs()) {
+		struct string_list keep_pack = STRING_LIST_INIT_NODUP;
+
+		if (big_pack_threshold) {
+			find_base_packs(&keep_pack, big_pack_threshold);
+			if (keep_pack.nr >= gc_auto_pack_limit) {
+				big_pack_threshold = 0;
+				string_list_clear(&keep_pack, 0);
+				find_base_packs(&keep_pack, 0);
+			}
+		} else {
+			struct packed_git *p = find_base_packs(&keep_pack, 0);
+			uint64_t mem_have, mem_want;
+
+			mem_have = total_ram();
+			mem_want = estimate_repack_memory(p);
+
+			/*
+			 * Only allow 1/2 of memory for pack-objects, leave
+			 * the rest for the OS and other processes in the
+			 * system.
+			 */
+			if (!mem_have || mem_want < mem_have / 2)
+				string_list_clear(&keep_pack, 0);
+		}
+
+		add_repack_all_option(&keep_pack);
+		string_list_clear(&keep_pack, 0);
+	} else if (too_many_loose_objects())
 		add_repack_incremental_option();
 	else
 		return 0;
@@ -234,7 +373,7 @@
 /* return NULL on success, else hostname running the gc */
 static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 {
-	static struct lock_file lock;
+	struct lock_file lock = LOCK_INIT;
 	char my_host[HOST_NAME_MAX + 1];
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
@@ -354,6 +493,8 @@
 	const char *name;
 	pid_t pid;
 	int daemonized = 0;
+	int keep_base_pack = -1;
+	timestamp_t dummy;
 
 	struct option builtin_gc_options[] = {
 		OPT__QUIET(&quiet, N_("suppress progress reporting")),
@@ -366,6 +507,8 @@
 		OPT_BOOL_F(0, "force", &force,
 			   N_("force running gc even if there may be another gc running"),
 			   PARSE_OPT_NOCOMPLETE),
+		OPT_BOOL(0, "keep-largest-pack", &keep_base_pack,
+			 N_("repack all other packs except the largest pack")),
 		OPT_END()
 	};
 
@@ -382,7 +525,7 @@
 	/* default expiry time, overwritten in gc_config */
 	gc_config();
 	if (parse_expiry_date(gc_log_expire, &gc_log_expire_time))
-		die(_("Failed to parse gc.logexpiry value %s"), gc_log_expire);
+		die(_("failed to parse gc.logexpiry value %s"), gc_log_expire);
 
 	if (pack_refs < 0)
 		pack_refs = !is_bare_repository();
@@ -392,6 +535,9 @@
 	if (argc > 0)
 		usage_with_options(builtin_gc_usage, builtin_gc_options);
 
+	if (prune_expire && parse_expiry_date(prune_expire, &dummy))
+		die(_("failed to parse prune expiry value %s"), prune_expire);
+
 	if (aggressive) {
 		argv_array_push(&repack, "-f");
 		if (aggressive_depth > 0)
@@ -431,8 +577,19 @@
 			 */
 			daemonized = !daemonize();
 		}
-	} else
-		add_repack_all_option();
+	} else {
+		struct string_list keep_pack = STRING_LIST_INIT_NODUP;
+
+		if (keep_base_pack != -1) {
+			if (keep_base_pack)
+				find_base_packs(&keep_pack, 0);
+		} else if (big_pack_threshold) {
+			find_base_packs(&keep_pack, big_pack_threshold);
+		}
+
+		add_repack_all_option(&keep_pack);
+		string_list_clear(&keep_pack, 0);
+	}
 
 	name = lock_repo_for_gc(force, &pid);
 	if (name) {
diff --git a/builtin/grep.c b/builtin/grep.c
index 5f32d2c..ee753a4 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -488,7 +488,8 @@
 		strbuf_addstr(&name, repo->submodule_prefix);
 	}
 
-	repo_read_index(repo);
+	if (repo_read_index(repo) < 0)
+		die("index file corrupt");
 
 	for (nr = 0; nr < repo->index->cache_nr; nr++) {
 		const struct cache_entry *ce = repo->index->cache[nr];
@@ -602,8 +603,7 @@
 }
 
 static int grep_object(struct grep_opt *opt, const struct pathspec *pathspec,
-		       struct object *obj, const char *name, const char *path,
-		       struct repository *repo)
+		       struct object *obj, const char *name, const char *path)
 {
 	if (obj->type == OBJ_BLOB)
 		return grep_oid(opt, &obj->oid, name, 0, path);
@@ -630,7 +630,7 @@
 		}
 		init_tree_desc(&tree, data, size);
 		hit = grep_tree(opt, pathspec, &tree, &base, base.len,
-				obj->type == OBJ_COMMIT, repo);
+				obj->type == OBJ_COMMIT, the_repository);
 		strbuf_release(&base);
 		free(data);
 		return hit;
@@ -639,7 +639,6 @@
 }
 
 static int grep_objects(struct grep_opt *opt, const struct pathspec *pathspec,
-			struct repository *repo,
 			const struct object_array *list)
 {
 	unsigned int i;
@@ -652,11 +651,11 @@
 
 		/* load the gitmodules file for this rev */
 		if (recurse_submodules) {
-			submodule_free();
+			submodule_free(the_repository);
 			gitmodules_config_oid(&real_obj->oid);
 		}
-		if (grep_object(opt, pathspec, real_obj, list->objects[i].name, list->objects[i].path,
-				repo)) {
+		if (grep_object(opt, pathspec, real_obj, list->objects[i].name,
+				list->objects[i].path)) {
 			hit = 1;
 			if (opt->status_only)
 				break;
@@ -887,9 +886,9 @@
 			   N_("indicate hit with exit status without output")),
 		OPT_BOOL(0, "all-match", &opt.all_match,
 			N_("show only matches from files that match all patterns")),
-		{ OPTION_SET_INT, 0, "debug", &opt.debug, NULL,
-		  N_("show parse tree for grep expression"),
-		  PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 1 },
+		OPT_SET_INT_F(0, "debug", &opt.debug,
+			      N_("show parse tree for grep expression"),
+			      1, PARSE_OPT_HIDDEN),
 		OPT_GROUP(""),
 		{ OPTION_STRING, 'O', "open-files-in-pager", &show_in_pager,
 			N_("pager"), N_("show matching files in the pager"),
@@ -1108,7 +1107,7 @@
 		if (cached)
 			die(_("both --cached and trees are given."));
 
-		hit = grep_objects(&opt, &pathspec, the_repository, &list);
+		hit = grep_objects(&opt, &pathspec, &list);
 	}
 
 	if (num_threads)
diff --git a/builtin/help.c b/builtin/help.c
index 2d51071..58e0a55 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -9,6 +9,7 @@
 #include "run-command.h"
 #include "column.h"
 #include "help.h"
+#include "alias.h"
 
 #ifndef DEFAULT_HELP_FORMAT
 #define DEFAULT_HELP_FORMAT "man"
@@ -36,6 +37,7 @@
 
 static int show_all = 0;
 static int show_guides = 0;
+static int verbose;
 static unsigned int colopts;
 static enum help_format help_format = HELP_FORMAT_NONE;
 static int exclude_guides;
@@ -48,6 +50,7 @@
 			HELP_FORMAT_WEB),
 	OPT_SET_INT('i', "info", &help_format, N_("show info page"),
 			HELP_FORMAT_INFO),
+	OPT__VERBOSE(&verbose, N_("print command description")),
 	OPT_END(),
 };
 
@@ -400,38 +403,6 @@
 	open_html(page_path.buf);
 }
 
-static struct {
-	const char *name;
-	const char *help;
-} common_guides[] = {
-	{ "attributes", N_("Defining attributes per path") },
-	{ "everyday", N_("Everyday Git With 20 Commands Or So") },
-	{ "glossary", N_("A Git glossary") },
-	{ "ignore", N_("Specifies intentionally untracked files to ignore") },
-	{ "modules", N_("Defining submodule properties") },
-	{ "revisions", N_("Specifying revisions and ranges for Git") },
-	{ "tutorial", N_("A tutorial introduction to Git (for version 1.5.1 or newer)") },
-	{ "workflows", N_("An overview of recommended workflows with Git") },
-};
-
-static void list_common_guides_help(void)
-{
-	int i, longest = 0;
-
-	for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
-		if (longest < strlen(common_guides[i].name))
-			longest = strlen(common_guides[i].name);
-	}
-
-	puts(_("The common Git guides are:\n"));
-	for (i = 0; i < ARRAY_SIZE(common_guides); i++) {
-		printf("   %s   ", common_guides[i].name);
-		mput_char(' ', longest - strlen(common_guides[i].name));
-		puts(_(common_guides[i].help));
-	}
-	putchar('\n');
-}
-
 static const char *check_git_cmd(const char* cmd)
 {
 	char *alias;
@@ -463,6 +434,11 @@
 
 	if (show_all) {
 		git_config(git_help_config, NULL);
+		if (verbose) {
+			setup_pager();
+			list_all_cmds_help();
+			return 0;
+		}
 		printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 		load_command_list("git-", &main_cmds, &other_cmds);
 		list_commands(colopts, &main_cmds, &other_cmds);
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 78e66b9..4ab31ed 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -223,7 +223,7 @@
 
 	if (!(obj->flags & FLAG_CHECKED)) {
 		unsigned long size;
-		int type = oid_object_info(&obj->oid, &size);
+		int type = oid_object_info(the_repository, &obj->oid, &size);
 		if (type <= 0)
 			die(_("did not receive expected object %s"),
 			      oid_to_hex(&obj->oid));
@@ -812,7 +812,7 @@
 		enum object_type has_type;
 		unsigned long has_size;
 		read_lock();
-		has_type = oid_object_info(oid, &has_size);
+		has_type = oid_object_info(the_repository, oid, &has_size);
 		if (has_type < 0)
 			die(_("cannot read existing object info %s"), oid_to_hex(oid));
 		if (has_type != type || has_size != size)
@@ -837,6 +837,9 @@
 				blob->object.flags |= FLAG_CHECKED;
 			else
 				die(_("invalid blob object %s"), oid_to_hex(oid));
+			if (do_fsck_object &&
+			    fsck_object(&blob->object, (void *)data, size, &fsck_options))
+				die(_("fsck error in packed object"));
 		} else {
 			struct object *obj;
 			int eaten;
@@ -854,7 +857,7 @@
 				die(_("invalid %s"), type_name(type));
 			if (do_fsck_object &&
 			    fsck_object(obj, buf, size, &fsck_options))
-				die(_("Error in object"));
+				die(_("fsck error in packed object"));
 			if (strict && fsck_walk(obj, NULL, &fsck_options))
 				die(_("Not all child objects of %s are reachable"), oid_to_hex(&obj->oid));
 
@@ -866,7 +869,7 @@
 			if (obj->type == OBJ_COMMIT) {
 				struct commit *commit = (struct commit *) obj;
 				if (detach_commit_buffer(commit, NULL) != data)
-					die("BUG: parse_object_buffer transmogrified our buffer");
+					BUG("parse_object_buffer transmogrified our buffer");
 			}
 			obj->flags |= FLAG_CHECKED;
 		}
@@ -1015,7 +1018,7 @@
 
 		if (!compare_and_swap_type(&child->real_type, OBJ_REF_DELTA,
 					   base->obj->real_type))
-			die("BUG: child->real_type != OBJ_REF_DELTA");
+			BUG("child->real_type != OBJ_REF_DELTA");
 
 		resolve_delta(child, base, result);
 		if (base->ref_first == base->ref_last && base->ofs_last == -1)
@@ -1271,7 +1274,7 @@
 			    nr_objects - nr_objects_initial);
 		stop_progress_msg(&progress, msg.buf);
 		strbuf_release(&msg);
-		hashclose(f, tail_hash, 0);
+		finalize_hashfile(f, tail_hash, 0);
 		hashcpy(read_hash, pack_hash);
 		fixup_pack_header_footer(output_fd, pack_hash,
 					 curr_pack, nr_objects,
@@ -1479,6 +1482,9 @@
 	} else
 		chmod(final_index_name, 0444);
 
+	if (do_fsck_object)
+		add_packed_git(final_index_name, strlen(final_index_name), 0);
+
 	if (!from_stdin) {
 		printf("%s\n", sha1_to_hex(hash));
 	} else {
@@ -1543,12 +1549,13 @@
 {
 	const uint32_t *idx1, *idx2;
 	uint32_t i;
+	const uint32_t hashwords = the_hash_algo->rawsz / sizeof(uint32_t);
 
 	/* The address of the 4-byte offset table */
 	idx1 = (((const uint32_t *)p->index_data)
 		+ 2 /* 8-byte header */
 		+ 256 /* fan out */
-		+ 5 * p->num_objects /* 20-byte SHA-1 table */
+		+ hashwords * p->num_objects /* object ID table */
 		+ p->num_objects /* CRC32 table */
 		);
 
@@ -1820,6 +1827,10 @@
 		      pack_hash);
 	else
 		close(input_fd);
+
+	if (do_fsck_object && fsck_finish(&fsck_options))
+		die(_("fsck error in pack objects"));
+
 	free(objects);
 	strbuf_release(&index_name_buf);
 	if (pack_name == NULL)
diff --git a/builtin/init-db.c b/builtin/init-db.c
index 2542c52..4ecf909 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -117,7 +117,7 @@
 
 	dir = opendir(template_path.buf);
 	if (!dir) {
-		warning(_("templates not found %s"), template_dir);
+		warning(_("templates not found in %s"), template_dir);
 		goto free_return;
 	}
 
@@ -391,7 +391,7 @@
 		else if (get_shared_repository() == PERM_EVERYBODY)
 			xsnprintf(buf, sizeof(buf), "%d", OLD_PERM_EVERYBODY);
 		else
-			die("BUG: invalid value for shared_repository");
+			BUG("invalid value for shared_repository");
 		git_config_set("core.sharedrepository", buf);
 		git_config_set("receive.denyNonFastforwards", "true");
 	}
diff --git a/builtin/log.c b/builtin/log.c
index 71f68a3..4686f68 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -1019,7 +1019,7 @@
 	    open_next_file(NULL, rev->numbered_files ? NULL : "cover-letter", rev, quiet))
 		return;
 
-	log_write_email_headers(rev, head, &pp.after_subject, &need_8bit_cte);
+	log_write_email_headers(rev, head, &pp.after_subject, &need_8bit_cte, 0);
 
 	for (i = 0; !need_8bit_cte && i < nr; i++) {
 		const char *buf = get_commit_buffer(list[i], NULL);
@@ -1067,8 +1067,8 @@
 
 	diff_setup_done(&opts);
 
-	diff_tree_oid(&origin->tree->object.oid,
-		      &head->tree->object.oid,
+	diff_tree_oid(get_commit_tree_oid(origin),
+		      get_commit_tree_oid(head),
 		      "", &opts);
 	diffcore_std(&opts);
 	diff_flush(&opts);
@@ -1474,9 +1474,9 @@
 			 N_("output all-zero hash in From header")),
 		OPT_BOOL(0, "ignore-if-in-upstream", &ignore_if_in_upstream,
 			 N_("don't include a patch matching a commit upstream")),
-		{ OPTION_SET_INT, 'p', "no-stat", &use_patch_format, NULL,
-		  N_("show patch format instead of default (patch + stat)"),
-		  PARSE_OPT_NONEG | PARSE_OPT_NOARG, NULL, 1},
+		OPT_SET_INT_F('p', "no-stat", &use_patch_format,
+			      N_("show patch format instead of default (patch + stat)"),
+			      1, PARSE_OPT_NONEG),
 		OPT_GROUP(N_("Messaging")),
 		{ OPTION_CALLBACK, 0, "add-header", NULL, N_("header"),
 			    N_("add email header"), 0, header_callback },
diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index a71f6bd..88bb201 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -166,7 +166,7 @@
 				 */
 				pos = index_name_pos(istate, ent->name, ent->len);
 				if (0 <= pos)
-					die("BUG: killed-file %.*s not found",
+					BUG("killed-file %.*s not found",
 						ent->len, ent->name);
 				pos = -pos - 1;
 				while (pos < istate->cache_nr &&
@@ -556,9 +556,9 @@
 		{ OPTION_CALLBACK, 0, "exclude-standard", &dir, NULL,
 			N_("add the standard git exclusions"),
 			PARSE_OPT_NOARG, option_parse_exclude_standard },
-		{ OPTION_SET_INT, 0, "full-name", &prefix_len, NULL,
-			N_("make the output relative to the project top directory"),
-			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL },
+		OPT_SET_INT_F(0, "full-name", &prefix_len,
+			      N_("make the output relative to the project top directory"),
+			      0, PARSE_OPT_NONEG),
 		OPT_BOOL(0, "recurse-submodules", &recurse_submodules,
 			N_("recurse through submodules")),
 		OPT_BOOL(0, "error-unmatch", &error_unmatch,
diff --git a/builtin/ls-remote.c b/builtin/ls-remote.c
index 540d564..1a25df7 100644
--- a/builtin/ls-remote.c
+++ b/builtin/ls-remote.c
@@ -1,7 +1,9 @@
 #include "builtin.h"
 #include "cache.h"
 #include "transport.h"
+#include "ref-filter.h"
 #include "remote.h"
+#include "refs.h"
 
 static const char * const ls_remote_usage[] = {
 	N_("git ls-remote [--heads] [--tags] [--refs] [--upload-pack=<exec>]\n"
@@ -43,10 +45,15 @@
 	int show_symref_target = 0;
 	const char *uploadpack = NULL;
 	const char **pattern = NULL;
+	struct argv_array ref_prefixes = ARGV_ARRAY_INIT;
+	int i;
+	struct string_list server_options = STRING_LIST_INIT_DUP;
 
 	struct remote *remote;
 	struct transport *transport;
 	const struct ref *ref;
+	struct ref_array ref_array;
+	static struct ref_sorting *sorting = NULL, **sorting_tail = &sorting;
 
 	struct option options[] = {
 		OPT__QUIET(&quiet, N_("do not print remote URL")),
@@ -60,14 +67,19 @@
 		OPT_BIT(0, "refs", &flags, N_("do not show peeled tags"), REF_NORMAL),
 		OPT_BOOL(0, "get-url", &get_url,
 			 N_("take url.<base>.insteadOf into account")),
+		OPT_CALLBACK(0 , "sort", sorting_tail, N_("key"),
+			     N_("field name to sort on"), &parse_opt_ref_sorting),
 		OPT_SET_INT_F(0, "exit-code", &status,
 			      N_("exit with exit code 2 if no matching refs are found"),
 			      2, PARSE_OPT_NOCOMPLETE),
 		OPT_BOOL(0, "symref", &show_symref_target,
 			 N_("show underlying ref in addition to the object pointed by it")),
+		OPT_STRING_LIST('o', "server-option", &server_options, N_("server-specific"), N_("option to transmit")),
 		OPT_END()
 	};
 
+	memset(&ref_array, 0, sizeof(ref_array));
+
 	argc = parse_options(argc, argv, prefix, options, ls_remote_usage,
 			     PARSE_OPT_STOP_AT_NON_OPTION);
 	dest = argv[0];
@@ -75,8 +87,17 @@
 	if (argc > 1) {
 		int i;
 		pattern = xcalloc(argc, sizeof(const char *));
-		for (i = 1; i < argc; i++)
+		for (i = 1; i < argc; i++) {
+			const char *glob;
 			pattern[i - 1] = xstrfmt("*/%s", argv[i]);
+
+			glob = strchr(argv[i], '*');
+			if (glob)
+				argv_array_pushf(&ref_prefixes, "%.*s",
+						 (int)(glob - argv[i]), argv[i]);
+			else
+				expand_ref_prefix(&ref_prefixes, argv[i]);
+		}
 	}
 
 	remote = remote_get(dest);
@@ -90,28 +111,46 @@
 
 	if (get_url) {
 		printf("%s\n", *remote->url);
+		UNLEAK(sorting);
 		return 0;
 	}
 
 	transport = transport_get(remote, NULL);
 	if (uploadpack != NULL)
 		transport_set_option(transport, TRANS_OPT_UPLOADPACK, uploadpack);
+	if (server_options.nr)
+		transport->server_options = &server_options;
 
-	ref = transport_get_remote_refs(transport);
-	if (transport_disconnect(transport))
+	ref = transport_get_remote_refs(transport, &ref_prefixes);
+	if (transport_disconnect(transport)) {
+		UNLEAK(sorting);
 		return 1;
+	}
 
 	if (!dest && !quiet)
 		fprintf(stderr, "From %s\n", *remote->url);
 	for ( ; ref; ref = ref->next) {
+		struct ref_array_item *item;
 		if (!check_ref_type(ref, flags))
 			continue;
 		if (!tail_match(pattern, ref->name))
 			continue;
+		item = ref_array_push(&ref_array, ref->name, &ref->old_oid);
+		item->symref = xstrdup_or_null(ref->symref);
+	}
+
+	if (sorting)
+		ref_array_sort(sorting, &ref_array);
+
+	for (i = 0; i < ref_array.nr; i++) {
+		const struct ref_array_item *ref = ref_array.items[i];
 		if (show_symref_target && ref->symref)
-			printf("ref: %s\t%s\n", ref->symref, ref->name);
-		printf("%s\t%s\n", oid_to_hex(&ref->old_oid), ref->name);
+			printf("ref: %s\t%s\n", ref->symref, ref->refname);
+		printf("%s\t%s\n", oid_to_hex(&ref->objectname), ref->refname);
 		status = 0; /* we found something */
 	}
+
+	UNLEAK(sorting);
+	UNLEAK(ref_array);
 	return status;
 }
diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
index d44b4f9..409da4e 100644
--- a/builtin/ls-tree.c
+++ b/builtin/ls-tree.c
@@ -94,7 +94,7 @@
 			char size_text[24];
 			if (!strcmp(type, blob_type)) {
 				unsigned long size;
-				if (oid_object_info(oid, &size) == OBJ_BAD)
+				if (oid_object_info(the_repository, oid, &size) == OBJ_BAD)
 					xsnprintf(size_text, sizeof(size_text),
 						  "BAD");
 				else
diff --git a/builtin/merge.c b/builtin/merge.c
index 9db5a2c..b00d6f4 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -14,6 +14,7 @@
 #include "run-command.h"
 #include "diff.h"
 #include "refs.h"
+#include "refspec.h"
 #include "commit.h"
 #include "diffcore.h"
 #include "revision.h"
@@ -34,6 +35,7 @@
 #include "string-list.h"
 #include "packfile.h"
 #include "tag.h"
+#include "alias.h"
 
 #define DEFAULT_TWOHEAD (1<<0)
 #define DEFAULT_OCTOPUS (1<<1)
@@ -213,9 +215,9 @@
 	OPT_BOOL('e', "edit", &option_edit,
 		N_("edit message before committing")),
 	OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
-	{ OPTION_SET_INT, 0, "ff-only", &fast_forward, NULL,
-		N_("abort if fast-forward is not possible"),
-		PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
+	OPT_SET_INT_F(0, "ff-only", &fast_forward,
+		      N_("abort if fast-forward is not possible"),
+		      FF_ONLY, PARSE_OPT_NONEG),
 	OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
 	OPT_BOOL(0, "verify-signatures", &verify_signatures,
 		N_("verify that the named commit has a valid GPG signature")),
@@ -280,7 +282,7 @@
 	return rc;
 }
 
-static void read_empty(unsigned const char *sha1, int verbose)
+static void read_empty(const struct object_id *oid, int verbose)
 {
 	int i = 0;
 	const char *args[7];
@@ -290,15 +292,15 @@
 		args[i++] = "-v";
 	args[i++] = "-m";
 	args[i++] = "-u";
-	args[i++] = EMPTY_TREE_SHA1_HEX;
-	args[i++] = sha1_to_hex(sha1);
+	args[i++] = empty_tree_oid_hex();
+	args[i++] = oid_to_hex(oid);
 	args[i] = NULL;
 
 	if (run_command_v_opt(args, RUN_GIT_CMD))
 		die(_("read-tree failed"));
 }
 
-static void reset_hard(unsigned const char *sha1, int verbose)
+static void reset_hard(const struct object_id *oid, int verbose)
 {
 	int i = 0;
 	const char *args[6];
@@ -308,7 +310,7 @@
 		args[i++] = "-v";
 	args[i++] = "--reset";
 	args[i++] = "-u";
-	args[i++] = sha1_to_hex(sha1);
+	args[i++] = oid_to_hex(oid);
 	args[i] = NULL;
 
 	if (run_command_v_opt(args, RUN_GIT_CMD))
@@ -324,7 +326,7 @@
 	if (is_null_oid(stash))
 		return;
 
-	reset_hard(head->hash, 1);
+	reset_hard(head, 1);
 
 	args[2] = oid_to_hex(stash);
 
@@ -647,7 +649,7 @@
 			      struct commit_list *remoteheads,
 			      struct commit *head)
 {
-	static struct lock_file lock;
+	struct lock_file lock = LOCK_INIT;
 	const char *head_arg = "HEAD";
 
 	hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
@@ -805,7 +807,7 @@
 {
 	struct object_id result_tree, result_commit;
 	struct commit_list *parents, **pptr = &parents;
-	static struct lock_file lock;
+	struct lock_file lock = LOCK_INIT;
 
 	hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
 	refresh_cache(REFRESH_QUIET);
@@ -1297,7 +1299,7 @@
 		if (remoteheads->next)
 			die(_("Can merge only exactly one commit into empty head"));
 		remote_head_oid = &remoteheads->item->object.oid;
-		read_empty(remote_head_oid->hash, 0);
+		read_empty(remote_head_oid, 0);
 		update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
 			   UPDATE_REFS_DIE_ON_ERR);
 		goto done;
diff --git a/builtin/mktag.c b/builtin/mktag.c
index 9f5a50a..82a6e86 100644
--- a/builtin/mktag.c
+++ b/builtin/mktag.c
@@ -1,5 +1,6 @@
 #include "builtin.h"
 #include "tag.h"
+#include "replace-object.h"
 
 /*
  * A signature file has a very simple fixed format: four lines
@@ -24,7 +25,7 @@
 	enum object_type type;
 	unsigned long size;
 	void *buffer = read_object_file(oid, &type, &size);
-	const struct object_id *repl = lookup_replace_object(oid);
+	const struct object_id *repl = lookup_replace_object(the_repository, oid);
 
 	if (buffer) {
 		if (type == type_from_string(expected_type))
diff --git a/builtin/mktree.c b/builtin/mktree.c
index 263c530..bb76b46 100644
--- a/builtin/mktree.c
+++ b/builtin/mktree.c
@@ -116,7 +116,7 @@
 	}
 
 	/* Check the type of object identified by sha1 */
-	obj_type = oid_object_info(&oid, NULL);
+	obj_type = oid_object_info(the_repository, &oid, NULL);
 	if (obj_type < 0) {
 		if (allow_missing) {
 			; /* no problem - missing objects are presumed to be of the right type */
diff --git a/builtin/mv.c b/builtin/mv.c
index 6d141f7..80bb967 100644
--- a/builtin/mv.c
+++ b/builtin/mv.c
@@ -72,7 +72,6 @@
 	return path;
 }
 
-static struct lock_file lock_file;
 #define SUBMODULE_WITH_GITDIR ((const char *)1)
 
 static void prepare_move_submodule(const char *src, int first,
@@ -131,6 +130,7 @@
 	enum update_mode { BOTH = 0, WORKING_DIRECTORY, INDEX } *modes;
 	struct stat st;
 	struct string_list src_for_dst = STRING_LIST_INIT_NODUP;
+	struct lock_file lock_file = LOCK_INIT;
 
 	git_config(git_default_config, NULL);
 
@@ -276,10 +276,12 @@
 			die_errno(_("renaming '%s' failed"), src);
 		}
 		if (submodule_gitfile[i]) {
-			if (submodule_gitfile[i] != SUBMODULE_WITH_GITDIR)
-				connect_work_tree_and_git_dir(dst, submodule_gitfile[i]);
 			if (!update_path_in_gitmodules(src, dst))
 				gitmodules_modified = 1;
+			if (submodule_gitfile[i] != SUBMODULE_WITH_GITDIR)
+				connect_work_tree_and_git_dir(dst,
+							      submodule_gitfile[i],
+							      1);
 		}
 
 		if (mode == WORKING_DIRECTORY)
diff --git a/builtin/notes.c b/builtin/notes.c
index e5bf80e..6981e2d 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -461,7 +461,7 @@
 	if (d.buf.len || allow_empty) {
 		write_note_data(&d, &new_note);
 		if (add_note(t, &object, &new_note, combine_notes_overwrite))
-			die("BUG: combine_notes_overwrite failed");
+			BUG("combine_notes_overwrite failed");
 		commit_notes(t, "Notes added by 'git notes add'");
 	} else {
 		fprintf(stderr, _("Removing note for object %s\n"),
@@ -544,7 +544,7 @@
 	}
 
 	if (add_note(t, &object, from_note, combine_notes_overwrite))
-		die("BUG: combine_notes_overwrite failed");
+		BUG("combine_notes_overwrite failed");
 	commit_notes(t, "Notes added by 'git notes copy'");
 out:
 	free_notes(t);
@@ -621,7 +621,7 @@
 	if (d.buf.len || allow_empty) {
 		write_note_data(&d, &new_note);
 		if (add_note(t, &object, &new_note, combine_notes_overwrite))
-			die("BUG: combine_notes_overwrite failed");
+			BUG("combine_notes_overwrite failed");
 		logmsg = xstrfmt("Notes added by 'git notes %s'", argv[0]);
 	} else {
 		fprintf(stderr, _("Removing note for object %s\n"),
@@ -778,13 +778,13 @@
 			   N_("resolve notes conflicts using the given strategy "
 			      "(manual/ours/theirs/union/cat_sort_uniq)")),
 		OPT_GROUP(N_("Committing unmerged notes")),
-		{ OPTION_SET_INT, 0, "commit", &do_commit, NULL,
-			N_("finalize notes merge by committing unmerged notes"),
-			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
+		OPT_SET_INT_F(0, "commit", &do_commit,
+			      N_("finalize notes merge by committing unmerged notes"),
+			      1, PARSE_OPT_NONEG),
 		OPT_GROUP(N_("Aborting notes merge resolution")),
-		{ OPTION_SET_INT, 0, "abort", &do_abort, NULL,
-			N_("abort notes merge"),
-			PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
+		OPT_SET_INT_F(0, "abort", &do_abort,
+			      N_("abort notes merge"),
+			      1, PARSE_OPT_NONEG),
 		OPT_END()
 	};
 
@@ -831,7 +831,7 @@
 		const char *short_ref = NULL;
 
 		if (!skip_prefix(o.local_ref, "refs/notes/", &short_ref))
-			die("BUG: local ref %s is outside of refs/notes/",
+			BUG("local ref %s is outside of refs/notes/",
 			    o.local_ref);
 
 		strbuf_addf(&merge_key, "notes.%s.mergeStrategy", short_ref);
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 4bdae5a..71056d8 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -30,6 +30,19 @@
 #include "list.h"
 #include "packfile.h"
 #include "object-store.h"
+#include "dir.h"
+
+#define IN_PACK(obj) oe_in_pack(&to_pack, obj)
+#define SIZE(obj) oe_size(&to_pack, obj)
+#define SET_SIZE(obj,size) oe_set_size(&to_pack, obj, size)
+#define DELTA_SIZE(obj) oe_delta_size(&to_pack, obj)
+#define DELTA(obj) oe_delta(&to_pack, obj)
+#define DELTA_CHILD(obj) oe_delta_child(&to_pack, obj)
+#define DELTA_SIBLING(obj) oe_delta_sibling(&to_pack, obj)
+#define SET_DELTA(obj, val) oe_set_delta(&to_pack, obj, val)
+#define SET_DELTA_SIZE(obj, val) oe_set_delta_size(&to_pack, obj, val)
+#define SET_DELTA_CHILD(obj, val) oe_set_delta_child(&to_pack, obj, val)
+#define SET_DELTA_SIBLING(obj, val) oe_set_delta_sibling(&to_pack, obj, val)
 
 static const char *pack_usage[] = {
 	N_("git pack-objects --stdout [<options>...] [< <ref-list> | < <object-list>]"),
@@ -45,7 +58,7 @@
 static struct packing_data to_pack;
 
 static struct pack_idx_entry **written_list;
-static uint32_t nr_result, nr_written;
+static uint32_t nr_result, nr_written, nr_seen;
 
 static int non_empty;
 static int reuse_delta = 1, reuse_object = 1;
@@ -55,7 +68,8 @@
 static int local;
 static int have_non_local_packs;
 static int incremental;
-static int ignore_packed_keep;
+static int ignore_packed_keep_on_disk;
+static int ignore_packed_keep_in_core;
 static int allow_ofs_delta;
 static struct pack_idx_option pack_idx_opts;
 static const char *base_name;
@@ -80,7 +94,7 @@
 static int exclude_promisor_objects;
 
 static unsigned long delta_cache_size = 0;
-static unsigned long max_delta_cache_size = 256 * 1024 * 1024;
+static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE;
 static unsigned long cache_max_small_delta_size = 1000;
 
 static unsigned long window_memory_limit = 0;
@@ -127,13 +141,14 @@
 	buf = read_object_file(&entry->idx.oid, &type, &size);
 	if (!buf)
 		die("unable to read %s", oid_to_hex(&entry->idx.oid));
-	base_buf = read_object_file(&entry->delta->idx.oid, &type, &base_size);
+	base_buf = read_object_file(&DELTA(entry)->idx.oid, &type,
+				    &base_size);
 	if (!base_buf)
 		die("unable to read %s",
-		    oid_to_hex(&entry->delta->idx.oid));
+		    oid_to_hex(&DELTA(entry)->idx.oid));
 	delta_buf = diff_delta(base_buf, base_size,
 			       buf, size, &delta_size, 0);
-	if (!delta_buf || delta_size != entry->delta_size)
+	if (!delta_buf || delta_size != DELTA_SIZE(entry))
 		die("delta size changed");
 	free(buf);
 	free(base_buf);
@@ -264,10 +279,11 @@
 	enum object_type type;
 	void *buf;
 	struct git_istream *st = NULL;
+	const unsigned hashsz = the_hash_algo->rawsz;
 
 	if (!usable_delta) {
-		if (entry->type == OBJ_BLOB &&
-		    entry->size > big_file_threshold &&
+		if (oe_type(entry) == OBJ_BLOB &&
+		    oe_size_greater_than(&to_pack, entry, big_file_threshold) &&
 		    (st = open_istream(&entry->idx.oid, &type, &size, NULL)) != NULL)
 			buf = NULL;
 		else {
@@ -283,15 +299,15 @@
 		FREE_AND_NULL(entry->delta_data);
 		entry->z_delta_size = 0;
 	} else if (entry->delta_data) {
-		size = entry->delta_size;
+		size = DELTA_SIZE(entry);
 		buf = entry->delta_data;
 		entry->delta_data = NULL;
-		type = (allow_ofs_delta && entry->delta->idx.offset) ?
+		type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 			OBJ_OFS_DELTA : OBJ_REF_DELTA;
 	} else {
 		buf = get_delta(entry);
-		size = entry->delta_size;
-		type = (allow_ofs_delta && entry->delta->idx.offset) ?
+		size = DELTA_SIZE(entry);
+		type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 			OBJ_OFS_DELTA : OBJ_REF_DELTA;
 	}
 
@@ -315,12 +331,12 @@
 		 * encoding of the relative offset for the delta
 		 * base from this object's position in the pack.
 		 */
-		off_t ofs = entry->idx.offset - entry->delta->idx.offset;
+		off_t ofs = entry->idx.offset - DELTA(entry)->idx.offset;
 		unsigned pos = sizeof(dheader) - 1;
 		dheader[pos] = ofs & 127;
 		while (ofs >>= 7)
 			dheader[--pos] = 128 | (--ofs & 127);
-		if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+		if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 			if (st)
 				close_istream(st);
 			free(buf);
@@ -332,19 +348,19 @@
 	} else if (type == OBJ_REF_DELTA) {
 		/*
 		 * Deltas with a base reference contain
-		 * an additional 20 bytes for the base sha1.
+		 * additional bytes for the base object ID.
 		 */
-		if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+		if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 			if (st)
 				close_istream(st);
 			free(buf);
 			return 0;
 		}
 		hashwrite(f, header, hdrlen);
-		hashwrite(f, entry->delta->idx.oid.hash, 20);
-		hdrlen += 20;
+		hashwrite(f, DELTA(entry)->idx.oid.hash, hashsz);
+		hdrlen += hashsz;
 	} else {
-		if (limit && hdrlen + datalen + 20 >= limit) {
+		if (limit && hdrlen + datalen + hashsz >= limit) {
 			if (st)
 				close_istream(st);
 			free(buf);
@@ -367,21 +383,23 @@
 static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
 				unsigned long limit, int usable_delta)
 {
-	struct packed_git *p = entry->in_pack;
+	struct packed_git *p = IN_PACK(entry);
 	struct pack_window *w_curs = NULL;
 	struct revindex_entry *revidx;
 	off_t offset;
-	enum object_type type = entry->type;
+	enum object_type type = oe_type(entry);
 	off_t datalen;
 	unsigned char header[MAX_PACK_OBJECT_HEADER],
 		      dheader[MAX_PACK_OBJECT_HEADER];
 	unsigned hdrlen;
+	const unsigned hashsz = the_hash_algo->rawsz;
+	unsigned long entry_size = SIZE(entry);
 
-	if (entry->delta)
-		type = (allow_ofs_delta && entry->delta->idx.offset) ?
+	if (DELTA(entry))
+		type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 			OBJ_OFS_DELTA : OBJ_REF_DELTA;
 	hdrlen = encode_in_pack_object_header(header, sizeof(header),
-					      type, entry->size);
+					      type, entry_size);
 
 	offset = entry->in_pack_offset;
 	revidx = find_pack_revindex(p, offset);
@@ -398,7 +416,7 @@
 	datalen -= entry->in_pack_header_size;
 
 	if (!pack_to_stdout && p->index_version == 1 &&
-	    check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
+	    check_pack_inflate(p, &w_curs, offset, datalen, entry_size)) {
 		error("corrupt packed object for %s",
 		      oid_to_hex(&entry->idx.oid));
 		unuse_pack(&w_curs);
@@ -406,12 +424,12 @@
 	}
 
 	if (type == OBJ_OFS_DELTA) {
-		off_t ofs = entry->idx.offset - entry->delta->idx.offset;
+		off_t ofs = entry->idx.offset - DELTA(entry)->idx.offset;
 		unsigned pos = sizeof(dheader) - 1;
 		dheader[pos] = ofs & 127;
 		while (ofs >>= 7)
 			dheader[--pos] = 128 | (--ofs & 127);
-		if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+		if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 			unuse_pack(&w_curs);
 			return 0;
 		}
@@ -420,16 +438,16 @@
 		hdrlen += sizeof(dheader) - pos;
 		reused_delta++;
 	} else if (type == OBJ_REF_DELTA) {
-		if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+		if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 			unuse_pack(&w_curs);
 			return 0;
 		}
 		hashwrite(f, header, hdrlen);
-		hashwrite(f, entry->delta->idx.oid.hash, 20);
-		hdrlen += 20;
+		hashwrite(f, DELTA(entry)->idx.oid.hash, hashsz);
+		hdrlen += hashsz;
 		reused_delta++;
 	} else {
-		if (limit && hdrlen + datalen + 20 >= limit) {
+		if (limit && hdrlen + datalen + hashsz >= limit) {
 			unuse_pack(&w_curs);
 			return 0;
 		}
@@ -465,28 +483,29 @@
 	else
 		limit = pack_size_limit - write_offset;
 
-	if (!entry->delta)
+	if (!DELTA(entry))
 		usable_delta = 0;	/* no delta */
 	else if (!pack_size_limit)
 	       usable_delta = 1;	/* unlimited packfile */
-	else if (entry->delta->idx.offset == (off_t)-1)
+	else if (DELTA(entry)->idx.offset == (off_t)-1)
 		usable_delta = 0;	/* base was written to another pack */
-	else if (entry->delta->idx.offset)
+	else if (DELTA(entry)->idx.offset)
 		usable_delta = 1;	/* base already exists in this pack */
 	else
 		usable_delta = 0;	/* base could end up in another pack */
 
 	if (!reuse_object)
 		to_reuse = 0;	/* explicit */
-	else if (!entry->in_pack)
+	else if (!IN_PACK(entry))
 		to_reuse = 0;	/* can't reuse what we don't have */
-	else if (entry->type == OBJ_REF_DELTA || entry->type == OBJ_OFS_DELTA)
+	else if (oe_type(entry) == OBJ_REF_DELTA ||
+		 oe_type(entry) == OBJ_OFS_DELTA)
 				/* check_object() decided it for us ... */
 		to_reuse = usable_delta;
 				/* ... but pack split may override that */
-	else if (entry->type != entry->in_pack_type)
+	else if (oe_type(entry) != entry->in_pack_type)
 		to_reuse = 0;	/* pack has delta which is unusable */
-	else if (entry->delta)
+	else if (DELTA(entry))
 		to_reuse = 0;	/* we want to pack afresh */
 	else
 		to_reuse = 1;	/* we have it in-pack undeltified,
@@ -538,12 +557,12 @@
 	}
 
 	/* if we are deltified, write out base object first. */
-	if (e->delta) {
+	if (DELTA(e)) {
 		e->idx.offset = 1; /* now recurse */
-		switch (write_one(f, e->delta, offset)) {
+		switch (write_one(f, DELTA(e), offset)) {
 		case WRITE_ONE_RECURSIVE:
 			/* we cannot depend on this one */
-			e->delta = NULL;
+			SET_DELTA(e, NULL);
 			break;
 		default:
 			break;
@@ -605,34 +624,34 @@
 			/* add this node... */
 			add_to_write_order(wo, endp, e);
 			/* all its siblings... */
-			for (s = e->delta_sibling; s; s = s->delta_sibling) {
+			for (s = DELTA_SIBLING(e); s; s = DELTA_SIBLING(s)) {
 				add_to_write_order(wo, endp, s);
 			}
 		}
 		/* drop down a level to add left subtree nodes if possible */
-		if (e->delta_child) {
+		if (DELTA_CHILD(e)) {
 			add_to_order = 1;
-			e = e->delta_child;
+			e = DELTA_CHILD(e);
 		} else {
 			add_to_order = 0;
 			/* our sibling might have some children, it is next */
-			if (e->delta_sibling) {
-				e = e->delta_sibling;
+			if (DELTA_SIBLING(e)) {
+				e = DELTA_SIBLING(e);
 				continue;
 			}
 			/* go back to our parent node */
-			e = e->delta;
-			while (e && !e->delta_sibling) {
+			e = DELTA(e);
+			while (e && !DELTA_SIBLING(e)) {
 				/* we're on the right side of a subtree, keep
 				 * going up until we can go right again */
-				e = e->delta;
+				e = DELTA(e);
 			}
 			if (!e) {
 				/* done- we hit our original root node */
 				return;
 			}
 			/* pass it off to sibling at this level */
-			e = e->delta_sibling;
+			e = DELTA_SIBLING(e);
 		}
 	};
 }
@@ -643,7 +662,7 @@
 {
 	struct object_entry *root;
 
-	for (root = e; root->delta; root = root->delta)
+	for (root = e; DELTA(root); root = DELTA(root))
 		; /* nothing */
 	add_descendants_to_write_order(wo, endp, root);
 }
@@ -658,8 +677,8 @@
 	for (i = 0; i < to_pack.nr_objects; i++) {
 		objects[i].tagged = 0;
 		objects[i].filled = 0;
-		objects[i].delta_child = NULL;
-		objects[i].delta_sibling = NULL;
+		SET_DELTA_CHILD(&objects[i], NULL);
+		SET_DELTA_SIBLING(&objects[i], NULL);
 	}
 
 	/*
@@ -669,11 +688,11 @@
 	 */
 	for (i = to_pack.nr_objects; i > 0;) {
 		struct object_entry *e = &objects[--i];
-		if (!e->delta)
+		if (!DELTA(e))
 			continue;
 		/* Mark me as the first child */
-		e->delta_sibling = e->delta->delta_child;
-		e->delta->delta_child = e;
+		e->delta_sibling_idx = DELTA(e)->delta_child_idx;
+		SET_DELTA_CHILD(DELTA(e), e);
 	}
 
 	/*
@@ -705,8 +724,8 @@
 	 * And then all remaining commits and tags.
 	 */
 	for (i = last_untagged; i < to_pack.nr_objects; i++) {
-		if (objects[i].type != OBJ_COMMIT &&
-		    objects[i].type != OBJ_TAG)
+		if (oe_type(&objects[i]) != OBJ_COMMIT &&
+		    oe_type(&objects[i]) != OBJ_TAG)
 			continue;
 		add_to_write_order(wo, &wo_end, &objects[i]);
 	}
@@ -715,7 +734,7 @@
 	 * And then all the trees.
 	 */
 	for (i = last_untagged; i < to_pack.nr_objects; i++) {
-		if (objects[i].type != OBJ_TREE)
+		if (oe_type(&objects[i]) != OBJ_TREE)
 			continue;
 		add_to_write_order(wo, &wo_end, &objects[i]);
 	}
@@ -752,7 +771,7 @@
 		die_errno("unable to seek in reused packfile");
 
 	if (reuse_packfile_offset < 0)
-		reuse_packfile_offset = reuse_packfile->pack_size - 20;
+		reuse_packfile_offset = reuse_packfile->pack_size - the_hash_algo->rawsz;
 
 	total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
 
@@ -837,11 +856,11 @@
 		 * If so, rewrite it like in fast-import
 		 */
 		if (pack_to_stdout) {
-			hashclose(f, oid.hash, CSUM_CLOSE);
+			finalize_hashfile(f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_CLOSE);
 		} else if (nr_written == nr_remaining) {
-			hashclose(f, oid.hash, CSUM_FSYNC);
+			finalize_hashfile(f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
 		} else {
-			int fd = hashclose(f, oid.hash, 0);
+			int fd = finalize_hashfile(f, oid.hash, 0);
 			fixup_pack_header_footer(fd, oid.hash, pack_tmp_name,
 						 nr_written, oid.hash, offset);
 			close(fd);
@@ -878,7 +897,8 @@
 
 			if (write_bitmap_index) {
 				bitmap_writer_set_checksum(oid.hash);
-				bitmap_writer_build_type_index(written_list, nr_written);
+				bitmap_writer_build_type_index(
+					&to_pack, written_list, nr_written);
 			}
 
 			finish_tmp_packfile(&tmpname, pack_tmp_name,
@@ -982,13 +1002,16 @@
 	 * Otherwise, we signal "-1" at the end to tell the caller that we do
 	 * not know either way, and it needs to check more packs.
 	 */
-	if (!ignore_packed_keep &&
+	if (!ignore_packed_keep_on_disk &&
+	    !ignore_packed_keep_in_core &&
 	    (!local || !have_non_local_packs))
 		return 1;
 
 	if (local && !p->pack_local)
 		return 0;
-	if (ignore_packed_keep && p->pack_local && p->pack_keep)
+	if (p->pack_local &&
+	    ((ignore_packed_keep_on_disk && p->pack_keep) ||
+	     (ignore_packed_keep_in_core && p->pack_keep_in_core)))
 		return 0;
 
 	/* we don't know yet; keep looking for more packs */
@@ -1012,7 +1035,7 @@
 	int want;
 	struct list_head *pos;
 
-	if (!exclude && local && has_loose_object_nonlocal(oid->hash))
+	if (!exclude && local && has_loose_object_nonlocal(oid))
 		return 0;
 
 	/*
@@ -1066,14 +1089,13 @@
 
 	entry = packlist_alloc(&to_pack, oid->hash, index_pos);
 	entry->hash = hash;
-	if (type)
-		entry->type = type;
+	oe_set_type(entry, type);
 	if (exclude)
 		entry->preferred_base = 1;
 	else
 		nr_result++;
 	if (found_pack) {
-		entry->in_pack = found_pack;
+		oe_set_in_pack(&to_pack, entry, found_pack);
 		entry->in_pack_offset = found_offset;
 	}
 
@@ -1091,6 +1113,8 @@
 	off_t found_offset = 0;
 	uint32_t index_pos;
 
+	display_progress(progress_state, ++nr_seen);
+
 	if (have_duplicate_entry(oid, exclude, &index_pos))
 		return 0;
 
@@ -1106,8 +1130,6 @@
 	create_object_entry(oid, type, pack_name_hash(name),
 			    exclude, name && no_try_delta(name),
 			    index_pos, found_pack, found_offset);
-
-	display_progress(progress_state, nr_result);
 	return 1;
 }
 
@@ -1118,6 +1140,8 @@
 {
 	uint32_t index_pos;
 
+	display_progress(progress_state, ++nr_seen);
+
 	if (have_duplicate_entry(oid, 0, &index_pos))
 		return 0;
 
@@ -1125,8 +1149,6 @@
 		return 0;
 
 	create_object_entry(oid, type, name_hash, 0, 0, index_pos, pack, offset);
-
-	display_progress(progress_state, nr_result);
 	return 1;
 }
 
@@ -1398,8 +1420,10 @@
 
 static void check_object(struct object_entry *entry)
 {
-	if (entry->in_pack) {
-		struct packed_git *p = entry->in_pack;
+	unsigned long canonical_size;
+
+	if (IN_PACK(entry)) {
+		struct packed_git *p = IN_PACK(entry);
 		struct pack_window *w_curs = NULL;
 		const unsigned char *base_ref = NULL;
 		struct object_entry *base_entry;
@@ -1407,6 +1431,8 @@
 		unsigned long avail;
 		off_t ofs;
 		unsigned char *buf, c;
+		enum object_type type;
+		unsigned long in_pack_size;
 
 		buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
 
@@ -1415,11 +1441,15 @@
 		 * since non-delta representations could still be reused.
 		 */
 		used = unpack_object_header_buffer(buf, avail,
-						   &entry->in_pack_type,
-						   &entry->size);
+						   &type,
+						   &in_pack_size);
 		if (used == 0)
 			goto give_up;
 
+		if (type < 0)
+			BUG("invalid type %d", type);
+		entry->in_pack_type = type;
+
 		/*
 		 * Determine if this is a delta and if so whether we can
 		 * reuse it or not.  Otherwise let's find out as cheaply as
@@ -1428,9 +1458,10 @@
 		switch (entry->in_pack_type) {
 		default:
 			/* Not a delta hence we've already got all we need. */
-			entry->type = entry->in_pack_type;
+			oe_set_type(entry, entry->in_pack_type);
+			SET_SIZE(entry, in_pack_size);
 			entry->in_pack_header_size = used;
-			if (entry->type < OBJ_COMMIT || entry->type > OBJ_BLOB)
+			if (oe_type(entry) < OBJ_COMMIT || oe_type(entry) > OBJ_BLOB)
 				goto give_up;
 			unuse_pack(&w_curs);
 			return;
@@ -1438,7 +1469,7 @@
 			if (reuse_delta && !entry->preferred_base)
 				base_ref = use_pack(p, &w_curs,
 						entry->in_pack_offset + used, NULL);
-			entry->in_pack_header_size = used + 20;
+			entry->in_pack_header_size = used + the_hash_algo->rawsz;
 			break;
 		case OBJ_OFS_DELTA:
 			buf = use_pack(p, &w_curs,
@@ -1484,25 +1515,29 @@
 			 * deltify other objects against, in order to avoid
 			 * circular deltas.
 			 */
-			entry->type = entry->in_pack_type;
-			entry->delta = base_entry;
-			entry->delta_size = entry->size;
-			entry->delta_sibling = base_entry->delta_child;
-			base_entry->delta_child = entry;
+			oe_set_type(entry, entry->in_pack_type);
+			SET_SIZE(entry, in_pack_size); /* delta size */
+			SET_DELTA(entry, base_entry);
+			SET_DELTA_SIZE(entry, in_pack_size);
+			entry->delta_sibling_idx = base_entry->delta_child_idx;
+			SET_DELTA_CHILD(base_entry, entry);
 			unuse_pack(&w_curs);
 			return;
 		}
 
-		if (entry->type) {
+		if (oe_type(entry)) {
+			off_t delta_pos;
+
 			/*
 			 * This must be a delta and we already know what the
 			 * final object type is.  Let's extract the actual
 			 * object size from the delta header.
 			 */
-			entry->size = get_size_from_delta(p, &w_curs,
-					entry->in_pack_offset + entry->in_pack_header_size);
-			if (entry->size == 0)
+			delta_pos = entry->in_pack_offset + entry->in_pack_header_size;
+			canonical_size = get_size_from_delta(p, &w_curs, delta_pos);
+			if (canonical_size == 0)
 				goto give_up;
+			SET_SIZE(entry, canonical_size);
 			unuse_pack(&w_curs);
 			return;
 		}
@@ -1516,27 +1551,34 @@
 		unuse_pack(&w_curs);
 	}
 
-	entry->type = oid_object_info(&entry->idx.oid, &entry->size);
-	/*
-	 * The error condition is checked in prepare_pack().  This is
-	 * to permit a missing preferred base object to be ignored
-	 * as a preferred base.  Doing so can result in a larger
-	 * pack file, but the transfer will still take place.
-	 */
+	oe_set_type(entry,
+		    oid_object_info(the_repository, &entry->idx.oid, &canonical_size));
+	if (entry->type_valid) {
+		SET_SIZE(entry, canonical_size);
+	} else {
+		/*
+		 * Bad object type is checked in prepare_pack().  This is
+		 * to permit a missing preferred base object to be ignored
+		 * as a preferred base.  Doing so can result in a larger
+		 * pack file, but the transfer will still take place.
+		 */
+	}
 }
 
 static int pack_offset_sort(const void *_a, const void *_b)
 {
 	const struct object_entry *a = *(struct object_entry **)_a;
 	const struct object_entry *b = *(struct object_entry **)_b;
+	const struct packed_git *a_in_pack = IN_PACK(a);
+	const struct packed_git *b_in_pack = IN_PACK(b);
 
 	/* avoid filesystem trashing with loose objects */
-	if (!a->in_pack && !b->in_pack)
+	if (!a_in_pack && !b_in_pack)
 		return oidcmp(&a->idx.oid, &b->idx.oid);
 
-	if (a->in_pack < b->in_pack)
+	if (a_in_pack < b_in_pack)
 		return -1;
-	if (a->in_pack > b->in_pack)
+	if (a_in_pack > b_in_pack)
 		return 1;
 	return a->in_pack_offset < b->in_pack_offset ? -1 :
 			(a->in_pack_offset > b->in_pack_offset);
@@ -1557,29 +1599,37 @@
  */
 static void drop_reused_delta(struct object_entry *entry)
 {
-	struct object_entry **p = &entry->delta->delta_child;
+	unsigned *idx = &to_pack.objects[entry->delta_idx - 1].delta_child_idx;
 	struct object_info oi = OBJECT_INFO_INIT;
+	enum object_type type;
+	unsigned long size;
 
-	while (*p) {
-		if (*p == entry)
-			*p = (*p)->delta_sibling;
+	while (*idx) {
+		struct object_entry *oe = &to_pack.objects[*idx - 1];
+
+		if (oe == entry)
+			*idx = oe->delta_sibling_idx;
 		else
-			p = &(*p)->delta_sibling;
+			idx = &oe->delta_sibling_idx;
 	}
-	entry->delta = NULL;
+	SET_DELTA(entry, NULL);
 	entry->depth = 0;
 
-	oi.sizep = &entry->size;
-	oi.typep = &entry->type;
-	if (packed_object_info(entry->in_pack, entry->in_pack_offset, &oi) < 0) {
+	oi.sizep = &size;
+	oi.typep = &type;
+	if (packed_object_info(the_repository, IN_PACK(entry), entry->in_pack_offset, &oi) < 0) {
 		/*
 		 * We failed to get the info from this pack for some reason;
 		 * fall back to sha1_object_info, which may find another copy.
-		 * And if that fails, the error will be recorded in entry->type
+		 * And if that fails, the error will be recorded in oe_type(entry)
 		 * and dealt with in prepare_pack().
 		 */
-		entry->type = oid_object_info(&entry->idx.oid, &entry->size);
+		oe_set_type(entry,
+			    oid_object_info(the_repository, &entry->idx.oid, &size));
+	} else {
+		oe_set_type(entry, type);
 	}
+	SET_SIZE(entry, size);
 }
 
 /*
@@ -1603,7 +1653,7 @@
 
 	for (cur = entry, total_depth = 0;
 	     cur;
-	     cur = cur->delta, total_depth++) {
+	     cur = DELTA(cur), total_depth++) {
 		if (cur->dfs_state == DFS_DONE) {
 			/*
 			 * We've already seen this object and know it isn't
@@ -1620,7 +1670,7 @@
 		 * is a bug.
 		 */
 		if (cur->dfs_state != DFS_NONE)
-			die("BUG: confusing delta dfs state in first pass: %d",
+			BUG("confusing delta dfs state in first pass: %d",
 			    cur->dfs_state);
 
 		/*
@@ -1628,7 +1678,7 @@
 		 * it's not a delta, we're done traversing, but we'll mark it
 		 * done to save time on future traversals.
 		 */
-		if (!cur->delta) {
+		if (!DELTA(cur)) {
 			cur->dfs_state = DFS_DONE;
 			break;
 		}
@@ -1651,7 +1701,7 @@
 		 * We keep all commits in the chain that we examined.
 		 */
 		cur->dfs_state = DFS_ACTIVE;
-		if (cur->delta->dfs_state == DFS_ACTIVE) {
+		if (DELTA(cur)->dfs_state == DFS_ACTIVE) {
 			drop_reused_delta(cur);
 			cur->dfs_state = DFS_DONE;
 			break;
@@ -1666,7 +1716,7 @@
 	 * an extra "next" pointer to keep going after we reset cur->delta.
 	 */
 	for (cur = entry; cur; cur = next) {
-		next = cur->delta;
+		next = DELTA(cur);
 
 		/*
 		 * We should have a chain of zero or more ACTIVE states down to
@@ -1677,7 +1727,7 @@
 		if (cur->dfs_state == DFS_DONE)
 			break;
 		else if (cur->dfs_state != DFS_ACTIVE)
-			die("BUG: confusing delta dfs state in second pass: %d",
+			BUG("confusing delta dfs state in second pass: %d",
 			    cur->dfs_state);
 
 		/*
@@ -1711,6 +1761,10 @@
 	uint32_t i;
 	struct object_entry **sorted_by_offset;
 
+	if (progress)
+		progress_state = start_progress(_("Counting objects"),
+						to_pack.nr_objects);
+
 	sorted_by_offset = xcalloc(to_pack.nr_objects, sizeof(struct object_entry *));
 	for (i = 0; i < to_pack.nr_objects; i++)
 		sorted_by_offset[i] = to_pack.objects + i;
@@ -1719,9 +1773,12 @@
 	for (i = 0; i < to_pack.nr_objects; i++) {
 		struct object_entry *entry = sorted_by_offset[i];
 		check_object(entry);
-		if (big_file_threshold < entry->size)
+		if (entry->type_valid &&
+		    oe_size_greater_than(&to_pack, entry, big_file_threshold))
 			entry->no_try_delta = 1;
+		display_progress(progress_state, i + 1);
 	}
+	stop_progress(&progress_state);
 
 	/*
 	 * This must happen in a second pass, since we rely on the delta
@@ -1746,10 +1803,14 @@
 {
 	const struct object_entry *a = *(struct object_entry **)_a;
 	const struct object_entry *b = *(struct object_entry **)_b;
+	enum object_type a_type = oe_type(a);
+	enum object_type b_type = oe_type(b);
+	unsigned long a_size = SIZE(a);
+	unsigned long b_size = SIZE(b);
 
-	if (a->type > b->type)
+	if (a_type > b_type)
 		return -1;
-	if (a->type < b->type)
+	if (a_type < b_type)
 		return 1;
 	if (a->hash > b->hash)
 		return -1;
@@ -1759,9 +1820,9 @@
 		return -1;
 	if (a->preferred_base < b->preferred_base)
 		return 1;
-	if (a->size > b->size)
+	if (a_size > b_size)
 		return -1;
-	if (a->size < b->size)
+	if (a_size < b_size)
 		return 1;
 	return a < b ? -1 : (a > b);  /* newest first */
 }
@@ -1814,6 +1875,46 @@
 
 #endif
 
+/*
+ * Return the size of the object without doing any delta
+ * reconstruction (so non-deltas are true object sizes, but deltas
+ * return the size of the delta data).
+ */
+unsigned long oe_get_size_slow(struct packing_data *pack,
+			       const struct object_entry *e)
+{
+	struct packed_git *p;
+	struct pack_window *w_curs;
+	unsigned char *buf;
+	enum object_type type;
+	unsigned long used, avail, size;
+
+	if (e->type_ != OBJ_OFS_DELTA && e->type_ != OBJ_REF_DELTA) {
+		read_lock();
+		if (oid_object_info(the_repository, &e->idx.oid, &size) < 0)
+			die(_("unable to get size of %s"),
+			    oid_to_hex(&e->idx.oid));
+		read_unlock();
+		return size;
+	}
+
+	p = oe_in_pack(pack, e);
+	if (!p)
+		BUG("when e->type is a delta, it must belong to a pack");
+
+	read_lock();
+	w_curs = NULL;
+	buf = use_pack(p, &w_curs, e->in_pack_offset, &avail);
+	used = unpack_object_header_buffer(buf, avail, &type, &size);
+	if (used == 0)
+		die(_("unable to parse object header of %s"),
+		    oid_to_hex(&e->idx.oid));
+
+	unuse_pack(&w_curs);
+	read_unlock();
+	return size;
+}
+
 static int try_delta(struct unpacked *trg, struct unpacked *src,
 		     unsigned max_depth, unsigned long *mem_usage)
 {
@@ -1825,7 +1926,7 @@
 	void *delta_buf;
 
 	/* Don't bother doing diffs between different types */
-	if (trg_entry->type != src_entry->type)
+	if (oe_type(trg_entry) != oe_type(src_entry))
 		return -1;
 
 	/*
@@ -1836,8 +1937,8 @@
 	 * it, we will still save the transfer cost, as we already know
 	 * the other side has it and we won't send src_entry at all.
 	 */
-	if (reuse_delta && trg_entry->in_pack &&
-	    trg_entry->in_pack == src_entry->in_pack &&
+	if (reuse_delta && IN_PACK(trg_entry) &&
+	    IN_PACK(trg_entry) == IN_PACK(src_entry) &&
 	    !src_entry->preferred_base &&
 	    trg_entry->in_pack_type != OBJ_REF_DELTA &&
 	    trg_entry->in_pack_type != OBJ_OFS_DELTA)
@@ -1848,19 +1949,19 @@
 		return 0;
 
 	/* Now some size filtering heuristics. */
-	trg_size = trg_entry->size;
-	if (!trg_entry->delta) {
-		max_size = trg_size/2 - 20;
+	trg_size = SIZE(trg_entry);
+	if (!DELTA(trg_entry)) {
+		max_size = trg_size/2 - the_hash_algo->rawsz;
 		ref_depth = 1;
 	} else {
-		max_size = trg_entry->delta_size;
+		max_size = DELTA_SIZE(trg_entry);
 		ref_depth = trg->depth;
 	}
 	max_size = (uint64_t)max_size * (max_depth - src->depth) /
 						(max_depth - ref_depth + 1);
 	if (max_size == 0)
 		return 0;
-	src_size = src_entry->size;
+	src_size = SIZE(src_entry);
 	sizediff = src_size < trg_size ? trg_size - src_size : 0;
 	if (sizediff >= max_size)
 		return 0;
@@ -1922,10 +2023,14 @@
 	delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
 	if (!delta_buf)
 		return 0;
+	if (delta_size >= (1U << OE_DELTA_SIZE_BITS)) {
+		free(delta_buf);
+		return 0;
+	}
 
-	if (trg_entry->delta) {
+	if (DELTA(trg_entry)) {
 		/* Prefer only shallower same-sized deltas. */
-		if (delta_size == trg_entry->delta_size &&
+		if (delta_size == DELTA_SIZE(trg_entry) &&
 		    src->depth + 1 >= trg->depth) {
 			free(delta_buf);
 			return 0;
@@ -1940,7 +2045,7 @@
 	free(trg_entry->delta_data);
 	cache_lock();
 	if (trg_entry->delta_data) {
-		delta_cache_size -= trg_entry->delta_size;
+		delta_cache_size -= DELTA_SIZE(trg_entry);
 		trg_entry->delta_data = NULL;
 	}
 	if (delta_cacheable(src_size, trg_size, delta_size)) {
@@ -1952,8 +2057,8 @@
 		free(delta_buf);
 	}
 
-	trg_entry->delta = src_entry;
-	trg_entry->delta_size = delta_size;
+	SET_DELTA(trg_entry, src_entry);
+	SET_DELTA_SIZE(trg_entry, delta_size);
 	trg->depth = src->depth + 1;
 
 	return 1;
@@ -1961,13 +2066,13 @@
 
 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
 {
-	struct object_entry *child = me->delta_child;
+	struct object_entry *child = DELTA_CHILD(me);
 	unsigned int m = n;
 	while (child) {
 		unsigned int c = check_delta_limit(child, n + 1);
 		if (m < c)
 			m = c;
-		child = child->delta_sibling;
+		child = DELTA_SIBLING(child);
 	}
 	return m;
 }
@@ -1978,7 +2083,7 @@
 	free_delta_index(n->index);
 	n->index = NULL;
 	if (n->data) {
-		freed_mem += n->entry->size;
+		freed_mem += SIZE(n->entry);
 		FREE_AND_NULL(n->data);
 	}
 	n->entry = NULL;
@@ -2036,7 +2141,7 @@
 		 * otherwise they would become too deep.
 		 */
 		max_depth = depth;
-		if (entry->delta_child) {
+		if (DELTA_CHILD(entry)) {
 			max_depth -= check_delta_limit(entry, 0);
 			if (max_depth <= 0)
 				goto next;
@@ -2074,19 +2179,26 @@
 		 * between writes at that moment.
 		 */
 		if (entry->delta_data && !pack_to_stdout) {
-			entry->z_delta_size = do_compress(&entry->delta_data,
-							  entry->delta_size);
-			cache_lock();
-			delta_cache_size -= entry->delta_size;
-			delta_cache_size += entry->z_delta_size;
-			cache_unlock();
+			unsigned long size;
+
+			size = do_compress(&entry->delta_data, DELTA_SIZE(entry));
+			if (size < (1U << OE_Z_DELTA_BITS)) {
+				entry->z_delta_size = size;
+				cache_lock();
+				delta_cache_size -= DELTA_SIZE(entry);
+				delta_cache_size += entry->z_delta_size;
+				cache_unlock();
+			} else {
+				FREE_AND_NULL(entry->delta_data);
+				entry->z_delta_size = 0;
+			}
 		}
 
 		/* if we made n a delta, and if n is already at max
 		 * depth, leaving it in the window is pointless.  we
 		 * should evict it first.
 		 */
-		if (entry->delta && max_depth <= n->depth)
+		if (DELTA(entry) && max_depth <= n->depth)
 			continue;
 
 		/*
@@ -2094,7 +2206,7 @@
 		 * currently deltified object, to keep it longer.  It will
 		 * be the first base object to be attempted next.
 		 */
-		if (entry->delta) {
+		if (DELTA(entry)) {
 			struct unpacked swap = array[best_base];
 			int dist = (window + idx - best_base) % window;
 			int dst = best_base;
@@ -2415,13 +2527,14 @@
 	for (i = 0; i < to_pack.nr_objects; i++) {
 		struct object_entry *entry = to_pack.objects + i;
 
-		if (entry->delta)
+		if (DELTA(entry))
 			/* This happens if we decided to reuse existing
 			 * delta from a pack.  "reuse_delta &&" is implied.
 			 */
 			continue;
 
-		if (entry->size < 50)
+		if (!entry->type_valid ||
+		    oe_size_less_than(&to_pack, entry, 50))
 			continue;
 
 		if (entry->no_try_delta)
@@ -2429,11 +2542,11 @@
 
 		if (!entry->preferred_base) {
 			nr_deltas++;
-			if (entry->type < 0)
+			if (oe_type(entry) < 0)
 				die("unable to get type of object %s",
 				    oid_to_hex(&entry->idx.oid));
 		} else {
-			if (entry->type < 0) {
+			if (oe_type(entry) < 0) {
 				/*
 				 * This object is not found, but we
 				 * don't have to include it anyway.
@@ -2542,7 +2655,7 @@
 			die("expected object ID, got garbage:\n %s", line);
 
 		add_preferred_base_object(p + 1);
-		add_object_entry(&oid, 0, p + 1, 0);
+		add_object_entry(&oid, OBJ_NONE, p + 1, 0);
 	}
 }
 
@@ -2675,7 +2788,7 @@
 		struct object_id oid;
 		struct object *o;
 
-		if (!p->pack_local || p->pack_keep)
+		if (!p->pack_local || p->pack_keep || p->pack_keep_in_core)
 			continue;
 		if (open_pack_index(p))
 			die("cannot open pack index");
@@ -2706,7 +2819,7 @@
 static int add_loose_object(const struct object_id *oid, const char *path,
 			    void *data)
 {
-	enum object_type type = oid_object_info(oid, NULL);
+	enum object_type type = oid_object_info(the_repository, oid, NULL);
 
 	if (type < 0) {
 		warning("loose object at %s could not be examined", path);
@@ -2738,7 +2851,8 @@
 					get_packed_git(the_repository);
 
 	while (p) {
-		if ((!p->pack_local || p->pack_keep) &&
+		if ((!p->pack_local || p->pack_keep ||
+				p->pack_keep_in_core) &&
 			find_pack_entry_one(oid->hash, p)) {
 			last_found = p;
 			return 1;
@@ -2781,7 +2895,7 @@
 	struct object_id oid;
 
 	for (p = get_packed_git(the_repository); p; p = p->next) {
-		if (!p->pack_local || p->pack_keep)
+		if (!p->pack_local || p->pack_keep || p->pack_keep_in_core)
 			continue;
 
 		if (open_pack_index(p))
@@ -2807,7 +2921,8 @@
 {
 	return pack_to_stdout &&
 	       allow_ofs_delta &&
-	       !ignore_packed_keep &&
+	       !ignore_packed_keep_on_disk &&
+	       !ignore_packed_keep_in_core &&
 	       (!local || !have_non_local_packs) &&
 	       !incremental;
 }
@@ -2916,6 +3031,32 @@
 	oid_array_clear(&recent_objects);
 }
 
+static void add_extra_kept_packs(const struct string_list *names)
+{
+	struct packed_git *p;
+
+	if (!names->nr)
+		return;
+
+	for (p = get_packed_git(the_repository); p; p = p->next) {
+		const char *name = basename(p->pack_name);
+		int i;
+
+		if (!p->pack_local)
+			continue;
+
+		for (i = 0; i < names->nr; i++)
+			if (!fspathcmp(name, names->items[i].string))
+				break;
+
+		if (i < names->nr) {
+			p->pack_keep_in_core = 1;
+			ignore_packed_keep_in_core = 1;
+			continue;
+		}
+	}
+}
+
 static int option_parse_index_version(const struct option *opt,
 				      const char *arg, int unset)
 {
@@ -2955,6 +3096,7 @@
 	struct argv_array rp = ARGV_ARRAY_INIT;
 	int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
 	int rev_list_index = 0;
+	struct string_list keep_pack_list = STRING_LIST_INIT_NODUP;
 	struct option pack_objects_options[] = {
 		OPT_SET_INT('q', "quiet", &progress,
 			    N_("do not show progress meter"), 0),
@@ -2992,18 +3134,18 @@
 			 N_("do not create an empty pack output")),
 		OPT_BOOL(0, "revs", &use_internal_rev_list,
 			 N_("read revision arguments from standard input")),
-		{ OPTION_SET_INT, 0, "unpacked", &rev_list_unpacked, NULL,
-		  N_("limit the objects to those that are not yet packed"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
-		{ OPTION_SET_INT, 0, "all", &rev_list_all, NULL,
-		  N_("include objects reachable from any reference"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
-		{ OPTION_SET_INT, 0, "reflog", &rev_list_reflog, NULL,
-		  N_("include objects referred by reflog entries"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
-		{ OPTION_SET_INT, 0, "indexed-objects", &rev_list_index, NULL,
-		  N_("include objects referred to by the index"),
-		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
+		OPT_SET_INT_F(0, "unpacked", &rev_list_unpacked,
+			      N_("limit the objects to those that are not yet packed"),
+			      1, PARSE_OPT_NONEG),
+		OPT_SET_INT_F(0, "all", &rev_list_all,
+			      N_("include objects reachable from any reference"),
+			      1, PARSE_OPT_NONEG),
+		OPT_SET_INT_F(0, "reflog", &rev_list_reflog,
+			      N_("include objects referred by reflog entries"),
+			      1, PARSE_OPT_NONEG),
+		OPT_SET_INT_F(0, "indexed-objects", &rev_list_index,
+			      N_("include objects referred to by the index"),
+			      1, PARSE_OPT_NONEG),
 		OPT_BOOL(0, "stdout", &pack_to_stdout,
 			 N_("output pack to stdout")),
 		OPT_BOOL(0, "include-tag", &include_tag,
@@ -3019,8 +3161,10 @@
 			 N_("create thin packs")),
 		OPT_BOOL(0, "shallow", &shallow,
 			 N_("create packs suitable for shallow fetches")),
-		OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep,
+		OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep_on_disk,
 			 N_("ignore packs that have companion .keep file")),
+		OPT_STRING_LIST(0, "keep-pack", &keep_pack_list, N_("name"),
+				N_("ignore this pack")),
 		OPT_INTEGER(0, "compression", &pack_compression_level,
 			    N_("pack compression level")),
 		OPT_SET_INT(0, "keep-true-parents", &grafts_replace_parents,
@@ -3038,6 +3182,9 @@
 		OPT_END(),
 	};
 
+	if (DFS_NUM_STATES > (1 << OE_DFS_STATE_BITS))
+		BUG("too many dfs states, increase OE_DFS_STATE_BITS");
+
 	check_replace_refs = 0;
 
 	reset_pack_idx_option(&pack_idx_opts);
@@ -3054,6 +3201,17 @@
 	if (pack_to_stdout != !base_name || argc)
 		usage_with_options(pack_usage, pack_objects_options);
 
+	if (depth >= (1 << OE_DEPTH_BITS)) {
+		warning(_("delta chain depth %d is too deep, forcing %d"),
+			depth, (1 << OE_DEPTH_BITS) - 1);
+		depth = (1 << OE_DEPTH_BITS) - 1;
+	}
+	if (cache_max_small_delta_size >= (1U << OE_Z_DELTA_BITS)) {
+		warning(_("pack.deltaCacheLimit is too high, forcing %d"),
+			(1U << OE_Z_DELTA_BITS) - 1);
+		cache_max_small_delta_size = (1U << OE_Z_DELTA_BITS) - 1;
+	}
+
 	argv_array_push(&rp, "pack-objects");
 	if (thin) {
 		use_internal_rev_list = 1;
@@ -3085,6 +3243,8 @@
 		fetch_if_missing = 0;
 		argv_array_push(&rp, "--exclude-promisor-objects");
 	}
+	if (unpack_unreachable || keep_unreachable || pack_loose_unreachable)
+		use_internal_rev_list = 1;
 
 	if (!reuse_object)
 		reuse_delta = 0;
@@ -3148,19 +3308,20 @@
 	if (progress && all_progress_implied)
 		progress = 2;
 
-	if (ignore_packed_keep) {
+	add_extra_kept_packs(&keep_pack_list);
+	if (ignore_packed_keep_on_disk) {
 		struct packed_git *p;
 		for (p = get_packed_git(the_repository); p; p = p->next)
 			if (p->pack_local && p->pack_keep)
 				break;
 		if (!p) /* no keep-able packs found */
-			ignore_packed_keep = 0;
+			ignore_packed_keep_on_disk = 0;
 	}
 	if (local) {
 		/*
-		 * unlike ignore_packed_keep above, we do not want to
-		 * unset "local" based on looking at packs, as it
-		 * also covers non-local objects
+		 * unlike ignore_packed_keep_on_disk above, we do not
+		 * want to unset "local" based on looking at packs, as
+		 * it also covers non-local objects
 		 */
 		struct packed_git *p;
 		for (p = get_packed_git(the_repository); p; p = p->next) {
@@ -3171,8 +3332,10 @@
 		}
 	}
 
+	prepare_packing_data(&to_pack);
+
 	if (progress)
-		progress_state = start_progress(_("Counting objects"), 0);
+		progress_state = start_progress(_("Enumerating objects"), 0);
 	if (!use_internal_rev_list)
 		read_object_list_from_stdin();
 	else {
diff --git a/builtin/pack-redundant.c b/builtin/pack-redundant.c
index 354478a..0494dce 100644
--- a/builtin/pack-redundant.c
+++ b/builtin/pack-redundant.c
@@ -20,7 +20,7 @@
 
 struct llist_item {
 	struct llist_item *next;
-	const unsigned char *sha1;
+	const struct object_id *oid;
 };
 static struct llist {
 	struct llist_item *front;
@@ -90,14 +90,14 @@
 		return ret;
 
 	new_item = ret->front = llist_item_get();
-	new_item->sha1 = list->front->sha1;
+	new_item->oid = list->front->oid;
 
 	old_item = list->front->next;
 	while (old_item) {
 		prev = new_item;
 		new_item = llist_item_get();
 		prev->next = new_item;
-		new_item->sha1 = old_item->sha1;
+		new_item->oid = old_item->oid;
 		old_item = old_item->next;
 	}
 	new_item->next = NULL;
@@ -108,10 +108,10 @@
 
 static inline struct llist_item *llist_insert(struct llist *list,
 					      struct llist_item *after,
-					       const unsigned char *sha1)
+					      const struct object_id *oid)
 {
 	struct llist_item *new_item = llist_item_get();
-	new_item->sha1 = sha1;
+	new_item->oid = oid;
 	new_item->next = NULL;
 
 	if (after != NULL) {
@@ -131,21 +131,21 @@
 }
 
 static inline struct llist_item *llist_insert_back(struct llist *list,
-						   const unsigned char *sha1)
+						   const struct object_id *oid)
 {
-	return llist_insert(list, list->back, sha1);
+	return llist_insert(list, list->back, oid);
 }
 
 static inline struct llist_item *llist_insert_sorted_unique(struct llist *list,
-			const unsigned char *sha1, struct llist_item *hint)
+			const struct object_id *oid, struct llist_item *hint)
 {
 	struct llist_item *prev = NULL, *l;
 
 	l = (hint == NULL) ? list->front : hint;
 	while (l) {
-		int cmp = hashcmp(l->sha1, sha1);
+		int cmp = oidcmp(l->oid, oid);
 		if (cmp > 0) { /* we insert before this entry */
-			return llist_insert(list, prev, sha1);
+			return llist_insert(list, prev, oid);
 		}
 		if (!cmp) { /* already exists */
 			return l;
@@ -154,11 +154,11 @@
 		l = l->next;
 	}
 	/* insert at the end */
-	return llist_insert_back(list, sha1);
+	return llist_insert_back(list, oid);
 }
 
 /* returns a pointer to an item in front of sha1 */
-static inline struct llist_item * llist_sorted_remove(struct llist *list, const unsigned char *sha1, struct llist_item *hint)
+static inline struct llist_item * llist_sorted_remove(struct llist *list, const struct object_id *oid, struct llist_item *hint)
 {
 	struct llist_item *prev, *l;
 
@@ -166,7 +166,7 @@
 	l = (hint == NULL) ? list->front : hint;
 	prev = NULL;
 	while (l) {
-		int cmp = hashcmp(l->sha1, sha1);
+		int cmp = oidcmp(l->oid, oid);
 		if (cmp > 0) /* not in list, since sorted */
 			return prev;
 		if (!cmp) { /* found */
@@ -201,7 +201,7 @@
 	b = B->front;
 
 	while (b) {
-		hint = llist_sorted_remove(A, b->sha1, hint);
+		hint = llist_sorted_remove(A, b->oid, hint);
 		b = b->next;
 	}
 }
@@ -252,13 +252,14 @@
 	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
 	const unsigned char *p1_base, *p2_base;
 	struct llist_item *p1_hint = NULL, *p2_hint = NULL;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 
 	p1_base = p1->pack->index_data;
 	p2_base = p2->pack->index_data;
 	p1_base += 256 * 4 + ((p1->pack->index_version < 2) ? 4 : 8);
 	p2_base += 256 * 4 + ((p2->pack->index_version < 2) ? 4 : 8);
-	p1_step = (p1->pack->index_version < 2) ? 24 : 20;
-	p2_step = (p2->pack->index_version < 2) ? 24 : 20;
+	p1_step = hashsz + ((p1->pack->index_version < 2) ? 4 : 0);
+	p2_step = hashsz + ((p2->pack->index_version < 2) ? 4 : 0);
 
 	while (p1_off < p1->pack->num_objects * p1_step &&
 	       p2_off < p2->pack->num_objects * p2_step)
@@ -267,9 +268,11 @@
 		/* cmp ~ p1 - p2 */
 		if (cmp == 0) {
 			p1_hint = llist_sorted_remove(p1->unique_objects,
-					p1_base + p1_off, p1_hint);
+					(const struct object_id *)(p1_base + p1_off),
+					p1_hint);
 			p2_hint = llist_sorted_remove(p2->unique_objects,
-					p1_base + p1_off, p2_hint);
+					(const struct object_id *)(p1_base + p1_off),
+					p2_hint);
 			p1_off += p1_step;
 			p2_off += p2_step;
 			continue;
@@ -359,13 +362,14 @@
 	size_t ret = 0;
 	unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
 	const unsigned char *p1_base, *p2_base;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 
 	p1_base = p1->index_data;
 	p2_base = p2->index_data;
 	p1_base += 256 * 4 + ((p1->index_version < 2) ? 4 : 8);
 	p2_base += 256 * 4 + ((p2->index_version < 2) ? 4 : 8);
-	p1_step = (p1->index_version < 2) ? 24 : 20;
-	p2_step = (p2->index_version < 2) ? 24 : 20;
+	p1_step = hashsz + ((p1->index_version < 2) ? 4 : 0);
+	p2_step = hashsz + ((p2->index_version < 2) ? 4 : 0);
 
 	while (p1_off < p1->num_objects * p1_step &&
 	       p2_off < p2->num_objects * p2_step)
@@ -499,7 +503,7 @@
 		l = pl->all_objects->front;
 		while (l) {
 			hint = llist_insert_sorted_unique(all_objects,
-							  l->sha1, hint);
+							  l->oid, hint);
 			l = l->next;
 		}
 		pl = pl->next;
@@ -558,9 +562,9 @@
 
 	base = p->index_data;
 	base += 256 * 4 + ((p->index_version < 2) ? 4 : 8);
-	step = (p->index_version < 2) ? 24 : 20;
+	step = the_hash_algo->rawsz + ((p->index_version < 2) ? 4 : 0);
 	while (off < p->num_objects * step) {
-		llist_insert_back(l.all_objects, base + off);
+		llist_insert_back(l.all_objects, (const struct object_id *)(base + off));
 		off += step;
 	}
 	/* this list will be pruned in cmp_two_packs later */
@@ -601,8 +605,8 @@
 	int i;
 	struct pack_list *min, *red, *pl;
 	struct llist *ignore;
-	unsigned char *sha1;
-	char buf[42]; /* 40 byte sha1 + \n + \0 */
+	struct object_id *oid;
+	char buf[GIT_MAX_HEXSZ + 2]; /* hex hash + \n + \0 */
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage(pack_redundant_usage);
@@ -650,10 +654,10 @@
 	llist_init(&ignore);
 	if (!isatty(0)) {
 		while (fgets(buf, sizeof(buf), stdin)) {
-			sha1 = xmalloc(20);
-			if (get_sha1_hex(buf, sha1))
-				die("Bad sha1 on stdin: %s", buf);
-			llist_insert_sorted_unique(ignore, sha1, NULL);
+			oid = xmalloc(sizeof(*oid));
+			if (get_oid_hex(buf, oid))
+				die("Bad object ID on stdin: %s", buf);
+			llist_insert_sorted_unique(ignore, oid, NULL);
 		}
 	}
 	llist_sorted_difference_inplace(all_objects, ignore);
diff --git a/builtin/pack-refs.c b/builtin/pack-refs.c
index b106a39..f335356 100644
--- a/builtin/pack-refs.c
+++ b/builtin/pack-refs.c
@@ -1,6 +1,7 @@
 #include "builtin.h"
 #include "parse-options.h"
 #include "refs.h"
+#include "repository.h"
 
 static char const * const pack_refs_usage[] = {
 	N_("git pack-refs [<options>]"),
@@ -17,5 +18,5 @@
 	};
 	if (parse_options(argc, argv, prefix, opts, pack_refs_usage, 0))
 		usage_with_options(pack_refs_usage, opts);
-	return refs_pack_refs(get_main_ref_store(), flags);
+	return refs_pack_refs(get_main_ref_store(the_repository), flags);
 }
diff --git a/builtin/prune-packed.c b/builtin/prune-packed.c
index 4192381..4ff525e 100644
--- a/builtin/prune-packed.c
+++ b/builtin/prune-packed.c
@@ -25,7 +25,7 @@
 {
 	int *opts = data;
 
-	if (!has_sha1_pack(oid->hash))
+	if (!has_object_pack(oid))
 		return 0;
 
 	if (*opts & PRUNE_PACKED_DRY_RUN)
diff --git a/builtin/prune.c b/builtin/prune.c
index 38ced18..518ffbe 100644
--- a/builtin/prune.c
+++ b/builtin/prune.c
@@ -50,7 +50,8 @@
 	if (st.st_mtime > expire)
 		return 0;
 	if (show_only || verbose) {
-		enum object_type type = oid_object_info(oid, NULL);
+		enum object_type type = oid_object_info(the_repository, oid,
+							NULL);
 		printf("%s %s\n", oid_to_hex(oid),
 		       (type > 0) ? type_name(type) : "unknown");
 	}
diff --git a/builtin/pull.c b/builtin/pull.c
index c719a4f..1f2ecf3 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -15,6 +15,7 @@
 #include "remote.h"
 #include "dir.h"
 #include "refs.h"
+#include "refspec.h"
 #include "revision.h"
 #include "submodule.h"
 #include "submodule-config.h"
@@ -543,7 +544,7 @@
 		argv_array_push(&args, repo);
 		argv_array_pushv(&args, refspecs);
 	} else if (*refspecs)
-		die("BUG: refspecs without repo?");
+		BUG("refspecs without repo?");
 	ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
 	argv_array_clear(&args);
 	return ret;
@@ -679,12 +680,12 @@
  */
 static const char *get_tracking_branch(const char *remote, const char *refspec)
 {
-	struct refspec *spec;
+	struct refspec_item spec;
 	const char *spec_src;
 	const char *merge_branch;
 
-	spec = parse_fetch_refspec(1, &refspec);
-	spec_src = spec->src;
+	refspec_item_init(&spec, refspec, REFSPEC_FETCH);
+	spec_src = spec.src;
 	if (!*spec_src || !strcmp(spec_src, "HEAD"))
 		spec_src = "HEAD";
 	else if (skip_prefix(spec_src, "heads/", &spec_src))
@@ -704,7 +705,7 @@
 	} else
 		merge_branch = NULL;
 
-	free_refspec(1, spec);
+	refspec_item_clear(&spec);
 	return merge_branch;
 }
 
diff --git a/builtin/push.c b/builtin/push.c
index 013c20d..9cd8e8c 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -4,6 +4,7 @@
 #include "cache.h"
 #include "config.h"
 #include "refs.h"
+#include "refspec.h"
 #include "run-command.h"
 #include "builtin.h"
 #include "remote.h"
@@ -12,12 +13,40 @@
 #include "submodule.h"
 #include "submodule-config.h"
 #include "send-pack.h"
+#include "color.h"
 
 static const char * const push_usage[] = {
 	N_("git push [<options>] [<repository> [<refspec>...]]"),
 	NULL,
 };
 
+static int push_use_color = -1;
+static char push_colors[][COLOR_MAXLEN] = {
+	GIT_COLOR_RESET,
+	GIT_COLOR_RED,	/* ERROR */
+};
+
+enum color_push {
+	PUSH_COLOR_RESET = 0,
+	PUSH_COLOR_ERROR = 1
+};
+
+static int parse_push_color_slot(const char *slot)
+{
+	if (!strcasecmp(slot, "reset"))
+		return PUSH_COLOR_RESET;
+	if (!strcasecmp(slot, "error"))
+		return PUSH_COLOR_ERROR;
+	return -1;
+}
+
+static const char *push_get_color(enum color_push ix)
+{
+	if (want_color_stderr(push_use_color))
+		return push_colors[ix];
+	return "";
+}
+
 static int thin = 1;
 static int deleterefs;
 static const char *receivepack;
@@ -28,19 +57,10 @@
 
 static struct push_cas_option cas;
 
-static const char **refspec;
-static int refspec_nr;
-static int refspec_alloc;
+static struct refspec rs = REFSPEC_INIT_PUSH;
 
 static struct string_list push_options_config = STRING_LIST_INIT_DUP;
 
-static void add_refspec(const char *ref)
-{
-	refspec_nr++;
-	ALLOC_GROW(refspec, refspec_nr, refspec_alloc);
-	refspec[refspec_nr-1] = ref;
-}
-
 static const char *map_refspec(const char *ref,
 			       struct remote *remote, struct ref *local_refs)
 {
@@ -50,12 +70,11 @@
 	if (count_refspec_match(ref, local_refs, &matched) != 1)
 		return ref;
 
-	if (remote->push) {
-		struct refspec query;
-		memset(&query, 0, sizeof(struct refspec));
+	if (remote->push.nr) {
+		struct refspec_item query;
+		memset(&query, 0, sizeof(struct refspec_item));
 		query.src = matched->name;
-		if (!query_refspecs(remote->push, remote->push_refspec_nr, &query) &&
-		    query.dst) {
+		if (!query_refspecs(&remote->push, &query) && query.dst) {
 			struct strbuf buf = STRBUF_INIT;
 			strbuf_addf(&buf, "%s%s:%s",
 				    query.force ? "+" : "",
@@ -110,7 +129,7 @@
 			}
 			ref = map_refspec(ref, remote, local_refs);
 		}
-		add_refspec(ref);
+		refspec_append(&rs, ref);
 	}
 }
 
@@ -198,7 +217,7 @@
 	}
 
 	strbuf_addf(&refspec, "%s:%s", branch->refname, branch->merge[0]->src);
-	add_refspec(refspec.buf);
+	refspec_append(&rs, refspec.buf);
 }
 
 static void setup_push_current(struct remote *remote, struct branch *branch)
@@ -208,7 +227,7 @@
 	if (!branch)
 		die(_(message_detached_head_die), remote->name);
 	strbuf_addf(&refspec, "%s:%s", branch->refname, branch->refname);
-	add_refspec(refspec.buf);
+	refspec_append(&rs, refspec.buf);
 }
 
 static int is_workflow_triangular(struct remote *remote)
@@ -225,7 +244,7 @@
 	switch (push_default) {
 	default:
 	case PUSH_DEFAULT_MATCHING:
-		add_refspec(":");
+		refspec_append(&rs, ":");
 		break;
 
 	case PUSH_DEFAULT_UNSPECIFIED:
@@ -313,7 +332,8 @@
 	advise(_(message_advice_ref_needs_force));
 }
 
-static int push_with_options(struct transport *transport, int flags)
+static int push_with_options(struct transport *transport, struct refspec *rs,
+			     int flags)
 {
 	int err;
 	unsigned int reject_reasons;
@@ -335,10 +355,12 @@
 
 	if (verbosity > 0)
 		fprintf(stderr, _("Pushing to %s\n"), transport->url);
-	err = transport_push(transport, refspec_nr, refspec, flags,
-			     &reject_reasons);
-	if (err != 0)
+	err = transport_push(transport, rs, flags, &reject_reasons);
+	if (err != 0) {
+		fprintf(stderr, "%s", push_get_color(PUSH_COLOR_ERROR));
 		error(_("failed to push some refs to '%s'"), transport->url);
+		fprintf(stderr, "%s", push_get_color(PUSH_COLOR_RESET));
+	}
 
 	err |= transport_disconnect(transport);
 	if (!err)
@@ -366,6 +388,7 @@
 	struct remote *remote = pushremote_get(repo);
 	const char **url;
 	int url_nr;
+	struct refspec *push_refspec = &rs;
 
 	if (!remote) {
 		if (repo)
@@ -386,27 +409,9 @@
 	if (push_options->nr)
 		flags |= TRANSPORT_PUSH_OPTIONS;
 
-	if ((flags & TRANSPORT_PUSH_ALL) && refspec) {
-		if (!strcmp(*refspec, "refs/tags/*"))
-			return error(_("--all and --tags are incompatible"));
-		return error(_("--all can't be combined with refspecs"));
-	}
-
-	if ((flags & TRANSPORT_PUSH_MIRROR) && refspec) {
-		if (!strcmp(*refspec, "refs/tags/*"))
-			return error(_("--mirror and --tags are incompatible"));
-		return error(_("--mirror can't be combined with refspecs"));
-	}
-
-	if ((flags & (TRANSPORT_PUSH_ALL|TRANSPORT_PUSH_MIRROR)) ==
-				(TRANSPORT_PUSH_ALL|TRANSPORT_PUSH_MIRROR)) {
-		return error(_("--all and --mirror are incompatible"));
-	}
-
-	if (!refspec && !(flags & TRANSPORT_PUSH_ALL)) {
-		if (remote->push_refspec_nr) {
-			refspec = remote->push_refspec;
-			refspec_nr = remote->push_refspec_nr;
+	if (!push_refspec->nr && !(flags & TRANSPORT_PUSH_ALL)) {
+		if (remote->push.nr) {
+			push_refspec = &remote->push;
 		} else if (!(flags & TRANSPORT_PUSH_MIRROR))
 			setup_default_push_refspecs(remote);
 	}
@@ -418,7 +423,7 @@
 				transport_get(remote, url[i]);
 			if (flags & TRANSPORT_PUSH_OPTIONS)
 				transport->push_options = push_options;
-			if (push_with_options(transport, flags))
+			if (push_with_options(transport, push_refspec, flags))
 				errs++;
 		}
 	} else {
@@ -426,7 +431,7 @@
 			transport_get(remote, NULL);
 		if (flags & TRANSPORT_PUSH_OPTIONS)
 			transport->push_options = push_options;
-		if (push_with_options(transport, flags))
+		if (push_with_options(transport, push_refspec, flags))
 			errs++;
 	}
 	return !!errs;
@@ -467,6 +472,7 @@
 
 static int git_push_config(const char *k, const char *v, void *cb)
 {
+	const char *slot_name;
 	int *flags = cb;
 	int status;
 
@@ -514,6 +520,16 @@
 			else
 				string_list_append(&push_options_config, v);
 		return 0;
+	} else if (!strcmp(k, "color.push")) {
+		push_use_color = git_config_colorbool(k, v);
+		return 0;
+	} else if (skip_prefix(k, "color.push.", &slot_name)) {
+		int slot = parse_push_color_slot(slot_name);
+		if (slot < 0)
+			return 0;
+		if (!v)
+			return config_error_nonbool(k);
+		return color_parse(v, push_colors[slot]);
 	}
 
 	return git_default_config(k, v, NULL);
@@ -583,6 +599,20 @@
 		die(_("--delete is incompatible with --all, --mirror and --tags"));
 	if (deleterefs && argc < 2)
 		die(_("--delete doesn't make sense without any refs"));
+	if (flags & TRANSPORT_PUSH_ALL) {
+		if (tags)
+			die(_("--all and --tags are incompatible"));
+		if (argc >= 2)
+			die(_("--all can't be combined with refspecs"));
+	}
+	if (flags & TRANSPORT_PUSH_MIRROR) {
+		if (tags)
+			die(_("--mirror and --tags are incompatible"));
+		if (argc >= 2)
+			die(_("--mirror can't be combined with refspecs"));
+	}
+	if ((flags & TRANSPORT_PUSH_ALL) && (flags & TRANSPORT_PUSH_MIRROR))
+		die(_("--all and --mirror are incompatible"));
 
 	if (recurse_submodules == RECURSE_SUBMODULES_CHECK)
 		flags |= TRANSPORT_RECURSE_SUBMODULES_CHECK;
@@ -592,7 +622,7 @@
 		flags |= TRANSPORT_RECURSE_SUBMODULES_ONLY;
 
 	if (tags)
-		add_refspec("refs/tags/*");
+		refspec_append(&rs, "refs/tags/*");
 
 	if (argc > 0) {
 		repo = argv[0];
diff --git a/builtin/read-tree.c b/builtin/read-tree.c
index bf87a27..ebc43eb 100644
--- a/builtin/read-tree.c
+++ b/builtin/read-tree.c
@@ -107,8 +107,6 @@
 	return git_default_config(var, value, cb);
 }
 
-static struct lock_file lock_file;
-
 int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
 {
 	int i, stage = 0;
@@ -116,6 +114,7 @@
 	struct tree_desc t[MAX_UNPACK_TREES];
 	struct unpack_trees_options opts;
 	int prefix_set = 0;
+	struct lock_file lock_file = LOCK_INIT;
 	const struct option read_tree_options[] = {
 		{ OPTION_CALLBACK, 0, "index-output", NULL, N_("file"),
 		  N_("write resulting index to <file>"),
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 4b68a28..68d36e0 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -454,21 +454,21 @@
 	/* RFC 2104 2. (6) & (7) */
 	git_SHA1_Init(&ctx);
 	git_SHA1_Update(&ctx, k_opad, sizeof(k_opad));
-	git_SHA1_Update(&ctx, out, 20);
+	git_SHA1_Update(&ctx, out, GIT_SHA1_RAWSZ);
 	git_SHA1_Final(out, &ctx);
 }
 
 static char *prepare_push_cert_nonce(const char *path, timestamp_t stamp)
 {
 	struct strbuf buf = STRBUF_INIT;
-	unsigned char sha1[20];
+	unsigned char sha1[GIT_SHA1_RAWSZ];
 
 	strbuf_addf(&buf, "%s:%"PRItime, path, stamp);
 	hmac_sha1(sha1, buf.buf, buf.len, cert_nonce_seed, strlen(cert_nonce_seed));;
 	strbuf_release(&buf);
 
 	/* RFC 2104 5. HMAC-SHA1-80 */
-	strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, 20, sha1_to_hex(sha1));
+	strbuf_addf(&buf, "%"PRItime"-%.*s", stamp, GIT_SHA1_HEXSZ, sha1_to_hex(sha1));
 	return strbuf_detach(&buf, NULL);
 }
 
@@ -876,7 +876,7 @@
 static int command_singleton_iterator(void *cb_data, struct object_id *oid);
 static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
 {
-	static struct lock_file shallow_lock;
+	struct lock_file shallow_lock = LOCK_INIT;
 	struct oid_array extra = OID_ARRAY_INIT;
 	struct check_connected_options opt = CHECK_CONNECTED_INIT;
 	uint32_t mask = 1 << (cmd->index % 32);
@@ -968,7 +968,7 @@
 		return "Working directory has unstaged changes";
 
 	/* diff-index with either HEAD or an empty tree */
-	diff_index[4] = head_has_history() ? "HEAD" : EMPTY_TREE_SHA1_HEX;
+	diff_index[4] = head_has_history() ? "HEAD" : empty_tree_oid_hex();
 
 	child_process_init(&child);
 	child.argv = diff_index;
@@ -1378,7 +1378,7 @@
 		}
 	}
 	if (!checked_connectivity)
-		die("BUG: connectivity check skipped???");
+		BUG("connectivity check skipped???");
 }
 
 static void execute_commands_non_atomic(struct command *commands,
@@ -1965,6 +1965,12 @@
 		unpack_limit = receive_unpack_limit;
 
 	switch (determine_protocol_version_server()) {
+	case protocol_v2:
+		/*
+		 * push support for protocol v2 has not been implemented yet,
+		 * so ignore the request to use v2 and fallback to using v0.
+		 */
+		break;
 	case protocol_v1:
 		/*
 		 * v1 is just the original protocol with a version string,
diff --git a/builtin/reflog.c b/builtin/reflog.c
index a89bd1d..a48984d 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -154,7 +154,7 @@
 		for (i = 0; i < found.nr; i++) {
 			struct commit *c =
 				(struct commit *)found.objects[i].item;
-			if (!tree_is_complete(&c->tree->object.oid)) {
+			if (!tree_is_complete(get_commit_tree_oid(c))) {
 				is_incomplete = 1;
 				c->object.flags |= INCOMPLETE;
 			}
diff --git a/builtin/remote.c b/builtin/remote.c
index 45c9219..1a82d85 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -7,6 +7,7 @@
 #include "strbuf.h"
 #include "run-command.h"
 #include "refs.h"
+#include "refspec.h"
 #include "argv-array.h"
 
 static const char * const builtin_remote_usage[] = {
@@ -336,10 +337,10 @@
 	struct ref *ref, *stale_refs;
 	int i;
 
-	for (i = 0; i < states->remote->fetch_refspec_nr; i++)
-		if (get_fetch_map(remote_refs, states->remote->fetch + i, &tail, 1))
+	for (i = 0; i < states->remote->fetch.nr; i++)
+		if (get_fetch_map(remote_refs, &states->remote->fetch.items[i], &tail, 1))
 			die(_("Could not get fetch map for refspec %s"),
-				states->remote->fetch_refspec[i]);
+				states->remote->fetch.raw[i]);
 
 	states->new_refs.strdup_strings = 1;
 	states->tracked.strdup_strings = 1;
@@ -350,8 +351,7 @@
 		else
 			string_list_append(&states->tracked, abbrev_branch(ref->name));
 	}
-	stale_refs = get_stale_heads(states->remote->fetch,
-				     states->remote->fetch_refspec_nr, fetch_map);
+	stale_refs = get_stale_heads(&states->remote->fetch, fetch_map);
 	for (ref = stale_refs; ref; ref = ref->next) {
 		struct string_list_item *item =
 			string_list_append(&states->stale, abbrev_branch(ref->name));
@@ -391,8 +391,7 @@
 	local_refs = get_local_heads();
 	push_map = copy_ref_list(remote_refs);
 
-	match_push_refs(local_refs, &push_map, remote->push_refspec_nr,
-			remote->push_refspec, MATCH_REFS_NONE);
+	match_push_refs(local_refs, &push_map, &remote->push, MATCH_REFS_NONE);
 
 	states->push.strdup_strings = 1;
 	for (ref = push_map; ref; ref = ref->next) {
@@ -438,14 +437,14 @@
 		return 0;
 
 	states->push.strdup_strings = 1;
-	if (!remote->push_refspec_nr) {
+	if (!remote->push.nr) {
 		item = string_list_append(&states->push, _("(matching)"));
 		info = item->util = xcalloc(1, sizeof(struct push_info));
 		info->status = PUSH_STATUS_NOTQUERIED;
 		info->dest = xstrdup(item->string);
 	}
-	for (i = 0; i < remote->push_refspec_nr; i++) {
-		struct refspec *spec = remote->push + i;
+	for (i = 0; i < remote->push.nr; i++) {
+		const struct refspec_item *spec = &remote->push.items[i];
 		if (spec->matching)
 			item = string_list_append(&states->push, _("(matching)"));
 		else if (strlen(spec->src))
@@ -465,7 +464,7 @@
 {
 	struct ref *ref, *matches;
 	struct ref *fetch_map = NULL, **fetch_map_tail = &fetch_map;
-	struct refspec refspec;
+	struct refspec_item refspec;
 
 	refspec.force = 0;
 	refspec.pattern = 1;
@@ -518,7 +517,7 @@
 	const struct object_id *oid, int flags, void *cb_data)
 {
 	struct branches_for_remote *branches = cb_data;
-	struct refspec refspec;
+	struct refspec_item refspec;
 	struct known_remote *kr;
 
 	memset(&refspec, 0, sizeof(refspec));
@@ -589,12 +588,12 @@
 		git_config_set_multivar(buf.buf, remote->url[i], "^$", 0);
 	strbuf_reset(&buf);
 	strbuf_addf(&buf, "remote.%s.push", remote->name);
-	for (i = 0; i < remote->push_refspec_nr; i++)
-		git_config_set_multivar(buf.buf, remote->push_refspec[i], "^$", 0);
+	for (i = 0; i < remote->push.raw_nr; i++)
+		git_config_set_multivar(buf.buf, remote->push.raw[i], "^$", 0);
 	strbuf_reset(&buf);
 	strbuf_addf(&buf, "remote.%s.fetch", remote->name);
-	for (i = 0; i < remote->fetch_refspec_nr; i++)
-		git_config_set_multivar(buf.buf, remote->fetch_refspec[i], "^$", 0);
+	for (i = 0; i < remote->fetch.raw_nr; i++)
+		git_config_set_multivar(buf.buf, remote->fetch.raw[i], "^$", 0);
 	if (remote->origin == REMOTE_REMOTES)
 		unlink_or_warn(git_path("remotes/%s", remote->name));
 	else if (remote->origin == REMOTE_BRANCHES)
@@ -649,11 +648,11 @@
 	strbuf_addf(&buf, "remote.%s.fetch", rename.new_name);
 	git_config_set_multivar(buf.buf, NULL, NULL, 1);
 	strbuf_addf(&old_remote_context, ":refs/remotes/%s/", rename.old_name);
-	for (i = 0; i < oldremote->fetch_refspec_nr; i++) {
+	for (i = 0; i < oldremote->fetch.raw_nr; i++) {
 		char *ptr;
 
 		strbuf_reset(&buf2);
-		strbuf_addstr(&buf2, oldremote->fetch_refspec[i]);
+		strbuf_addstr(&buf2, oldremote->fetch.raw[i]);
 		ptr = strstr(buf2.buf, old_remote_context.buf);
 		if (ptr) {
 			refspec_updated = 1;
@@ -837,7 +836,7 @@
 	const struct object_id *oid, int flags, void *cb_data)
 {
 	struct ref_states *states = cb_data;
-	struct refspec refspec;
+	struct refspec_item refspec;
 
 	if (flags & REF_ISSYMREF)
 		return 0;
@@ -866,7 +865,7 @@
 	if (query) {
 		transport = transport_get(states->remote, states->remote->url_nr > 0 ?
 			states->remote->url[0] : NULL);
-		remote_refs = transport_get_remote_refs(transport);
+		remote_refs = transport_get_remote_refs(transport, NULL);
 		transport_disconnect(transport);
 
 		states->queried = 1;
diff --git a/builtin/repack.c b/builtin/repack.c
index 7bdb401..6c636e1 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -86,7 +86,8 @@
  * have a corresponding .keep or .promisor file. These packs are not to
  * be kept if we are going to pack everything into one file.
  */
-static void get_non_kept_pack_filenames(struct string_list *fname_list)
+static void get_non_kept_pack_filenames(struct string_list *fname_list,
+					const struct string_list *extra_keep)
 {
 	DIR *dir;
 	struct dirent *e;
@@ -97,6 +98,14 @@
 
 	while ((e = readdir(dir)) != NULL) {
 		size_t len;
+		int i;
+
+		for (i = 0; i < extra_keep->nr; i++)
+			if (!fspathcmp(e->d_name, extra_keep->items[i].string))
+				break;
+		if (extra_keep->nr > 0 && i < extra_keep->nr)
+			continue;
+
 		if (!strip_suffix(e->d_name, ".pack", &len))
 			continue;
 
@@ -148,7 +157,7 @@
 	struct string_list rollback = STRING_LIST_INIT_NODUP;
 	struct string_list existing_packs = STRING_LIST_INIT_DUP;
 	struct strbuf line = STRBUF_INIT;
-	int ext, ret, failed;
+	int i, ext, ret, failed;
 	FILE *out;
 
 	/* variables to be filled by option parsing */
@@ -160,6 +169,7 @@
 	const char *depth = NULL;
 	const char *threads = NULL;
 	const char *max_pack_size = NULL;
+	struct string_list keep_pack_list = STRING_LIST_INIT_NODUP;
 	int no_reuse_delta = 0, no_reuse_object = 0;
 	int no_update_server_info = 0;
 	int quiet = 0;
@@ -200,6 +210,8 @@
 				N_("maximum size of each packfile")),
 		OPT_BOOL(0, "pack-kept-objects", &pack_kept_objects,
 				N_("repack objects in packs marked with .keep")),
+		OPT_STRING_LIST(0, "keep-pack", &keep_pack_list, N_("name"),
+				N_("do not repack this pack")),
 		OPT_END()
 	};
 
@@ -230,6 +242,9 @@
 	argv_array_push(&cmd.args, "--keep-true-parents");
 	if (!pack_kept_objects)
 		argv_array_push(&cmd.args, "--honor-pack-keep");
+	for (i = 0; i < keep_pack_list.nr; i++)
+		argv_array_pushf(&cmd.args, "--keep-pack=%s",
+				 keep_pack_list.items[i].string);
 	argv_array_push(&cmd.args, "--non-empty");
 	argv_array_push(&cmd.args, "--all");
 	argv_array_push(&cmd.args, "--reflog");
@@ -254,7 +269,7 @@
 		argv_array_push(&cmd.args, "--write-bitmap-index");
 
 	if (pack_everything & ALL_INTO_ONE) {
-		get_non_kept_pack_filenames(&existing_packs);
+		get_non_kept_pack_filenames(&existing_packs, &keep_pack_list);
 
 		if (existing_packs.nr && delete_redundant) {
 			if (unpack_unreachable) {
diff --git a/builtin/replace.c b/builtin/replace.c
index 935647b..6da2411 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -14,12 +14,15 @@
 #include "refs.h"
 #include "parse-options.h"
 #include "run-command.h"
+#include "object-store.h"
+#include "repository.h"
 #include "tag.h"
 
 static const char * const git_replace_usage[] = {
 	N_("git replace [-f] <object> <replacement>"),
 	N_("git replace [-f] --edit <object>"),
 	N_("git replace [-f] --graft <commit> [<parent>...]"),
+	N_("git replace [-f] --convert-graft-file"),
 	N_("git replace -d <object>..."),
 	N_("git replace [--format=<format>] [-l [<pattern>]]"),
 	NULL
@@ -53,8 +56,9 @@
 			if (get_oid(refname, &object))
 				return error("Failed to resolve '%s' as a valid ref.", refname);
 
-			obj_type = oid_object_info(&object, NULL);
-			repl_type = oid_object_info(oid, NULL);
+			obj_type = oid_object_info(the_repository, &object,
+						   NULL);
+			repl_type = oid_object_info(the_repository, oid, NULL);
 
 			printf("%s (%s) -> %s (%s)\n", refname, type_name(obj_type),
 			       oid_to_hex(oid), type_name(repl_type));
@@ -79,11 +83,11 @@
 	else if (!strcmp(format, "long"))
 		data.format = REPLACE_FORMAT_LONG;
 	else
-		die("invalid replace format '%s'\n"
-		    "valid formats are 'short', 'medium' and 'long'\n",
-		    format);
+		return error("invalid replace format '%s'\n"
+			     "valid formats are 'short', 'medium' and 'long'\n",
+			     format);
 
-	for_each_replace_ref(show_reference, (void *)&data);
+	for_each_replace_ref(the_repository, show_reference, (void *)&data);
 
 	return 0;
 }
@@ -134,7 +138,7 @@
 	return 0;
 }
 
-static void check_ref_valid(struct object_id *object,
+static int check_ref_valid(struct object_id *object,
 			    struct object_id *prev,
 			    struct strbuf *ref,
 			    int force)
@@ -142,12 +146,13 @@
 	strbuf_reset(ref);
 	strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
 	if (check_refname_format(ref->buf, 0))
-		die("'%s' is not a valid ref name.", ref->buf);
+		return error("'%s' is not a valid ref name.", ref->buf);
 
 	if (read_ref(ref->buf, prev))
 		oidclr(prev);
 	else if (!force)
-		die("replace ref '%s' already exists", ref->buf);
+		return error("replace ref '%s' already exists", ref->buf);
+	return 0;
 }
 
 static int replace_object_oid(const char *object_ref,
@@ -161,28 +166,33 @@
 	struct strbuf ref = STRBUF_INIT;
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
+	int res = 0;
 
-	obj_type = oid_object_info(object, NULL);
-	repl_type = oid_object_info(repl, NULL);
+	obj_type = oid_object_info(the_repository, object, NULL);
+	repl_type = oid_object_info(the_repository, repl, NULL);
 	if (!force && obj_type != repl_type)
-		die("Objects must be of the same type.\n"
-		    "'%s' points to a replaced object of type '%s'\n"
-		    "while '%s' points to a replacement object of type '%s'.",
-		    object_ref, type_name(obj_type),
-		    replace_ref, type_name(repl_type));
+		return error("Objects must be of the same type.\n"
+			     "'%s' points to a replaced object of type '%s'\n"
+			     "while '%s' points to a replacement object of "
+			     "type '%s'.",
+			     object_ref, type_name(obj_type),
+			     replace_ref, type_name(repl_type));
 
-	check_ref_valid(object, &prev, &ref, force);
+	if (check_ref_valid(object, &prev, &ref, force)) {
+		strbuf_release(&ref);
+		return -1;
+	}
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, ref.buf, repl, &prev,
 				   0, NULL, &err) ||
 	    ref_transaction_commit(transaction, &err))
-		die("%s", err.buf);
+		res = error("%s", err.buf);
 
 	ref_transaction_free(transaction);
 	strbuf_release(&ref);
-	return 0;
+	return res;
 }
 
 static int replace_object(const char *object_ref, const char *replace_ref, int force)
@@ -190,9 +200,11 @@
 	struct object_id object, repl;
 
 	if (get_oid(object_ref, &object))
-		die("Failed to resolve '%s' as a valid ref.", object_ref);
+		return error("Failed to resolve '%s' as a valid ref.",
+			     object_ref);
 	if (get_oid(replace_ref, &repl))
-		die("Failed to resolve '%s' as a valid ref.", replace_ref);
+		return error("Failed to resolve '%s' as a valid ref.",
+			     replace_ref);
 
 	return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
 }
@@ -202,7 +214,7 @@
  * If "raw" is true, then the object's raw contents are printed according to
  * "type". Otherwise, we pretty-print the contents for human editing.
  */
-static void export_object(const struct object_id *oid, enum object_type type,
+static int export_object(const struct object_id *oid, enum object_type type,
 			  int raw, const char *filename)
 {
 	struct child_process cmd = CHILD_PROCESS_INIT;
@@ -210,7 +222,7 @@
 
 	fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 	if (fd < 0)
-		die_errno("unable to open %s for writing", filename);
+		return error_errno("unable to open %s for writing", filename);
 
 	argv_array_push(&cmd.args, "--no-replace-objects");
 	argv_array_push(&cmd.args, "cat-file");
@@ -223,7 +235,8 @@
 	cmd.out = fd;
 
 	if (run_command(&cmd))
-		die("cat-file reported failure");
+		return error("cat-file reported failure");
+	return 0;
 }
 
 /*
@@ -231,14 +244,14 @@
  * interpreting it as "type", and writing the result to the object database.
  * The sha1 of the written object is returned via sha1.
  */
-static void import_object(struct object_id *oid, enum object_type type,
+static int import_object(struct object_id *oid, enum object_type type,
 			  int raw, const char *filename)
 {
 	int fd;
 
 	fd = open(filename, O_RDONLY);
 	if (fd < 0)
-		die_errno("unable to open %s for reading", filename);
+		return error_errno("unable to open %s for reading", filename);
 
 	if (!raw && type == OBJ_TREE) {
 		const char *argv[] = { "mktree", NULL };
@@ -250,27 +263,40 @@
 		cmd.in = fd;
 		cmd.out = -1;
 
-		if (start_command(&cmd))
-			die("unable to spawn mktree");
+		if (start_command(&cmd)) {
+			close(fd);
+			return error("unable to spawn mktree");
+		}
 
-		if (strbuf_read(&result, cmd.out, 41) < 0)
-			die_errno("unable to read from mktree");
+		if (strbuf_read(&result, cmd.out, 41) < 0) {
+			error_errno("unable to read from mktree");
+			close(fd);
+			close(cmd.out);
+			return -1;
+		}
 		close(cmd.out);
 
-		if (finish_command(&cmd))
-			die("mktree reported failure");
-		if (get_oid_hex(result.buf, oid) < 0)
-			die("mktree did not return an object name");
+		if (finish_command(&cmd)) {
+			strbuf_release(&result);
+			return error("mktree reported failure");
+		}
+		if (get_oid_hex(result.buf, oid) < 0) {
+			strbuf_release(&result);
+			return error("mktree did not return an object name");
+		}
 
 		strbuf_release(&result);
 	} else {
 		struct stat st;
 		int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
 
-		if (fstat(fd, &st) < 0)
-			die_errno("unable to fstat %s", filename);
+		if (fstat(fd, &st) < 0) {
+			error_errno("unable to fstat %s", filename);
+			close(fd);
+			return -1;
+		}
 		if (index_fd(oid, fd, &st, type, NULL, flags) < 0)
-			die("unable to write object to database");
+			return error("unable to write object to database");
 		/* index_fd close()s fd for us */
 	}
 
@@ -278,30 +304,43 @@
 	 * No need to close(fd) here; both run-command and index-fd
 	 * will have done it for us.
 	 */
+	return 0;
 }
 
 static int edit_and_replace(const char *object_ref, int force, int raw)
 {
-	char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
+	char *tmpfile;
 	enum object_type type;
 	struct object_id old_oid, new_oid, prev;
 	struct strbuf ref = STRBUF_INIT;
 
 	if (get_oid(object_ref, &old_oid) < 0)
-		die("Not a valid object name: '%s'", object_ref);
+		return error("Not a valid object name: '%s'", object_ref);
 
-	type = oid_object_info(&old_oid, NULL);
+	type = oid_object_info(the_repository, &old_oid, NULL);
 	if (type < 0)
-		die("unable to get object type for %s", oid_to_hex(&old_oid));
+		return error("unable to get object type for %s",
+			     oid_to_hex(&old_oid));
 
-	check_ref_valid(&old_oid, &prev, &ref, force);
+	if (check_ref_valid(&old_oid, &prev, &ref, force)) {
+		strbuf_release(&ref);
+		return -1;
+	}
 	strbuf_release(&ref);
 
-	export_object(&old_oid, type, raw, tmpfile);
-	if (launch_editor(tmpfile, NULL, NULL) < 0)
-		die("editing object file failed");
-	import_object(&new_oid, type, raw, tmpfile);
-
+	tmpfile = git_pathdup("REPLACE_EDITOBJ");
+	if (export_object(&old_oid, type, raw, tmpfile)) {
+		free(tmpfile);
+		return -1;
+	}
+	if (launch_editor(tmpfile, NULL, NULL) < 0) {
+		free(tmpfile);
+		return error("editing object file failed");
+	}
+	if (import_object(&new_oid, type, raw, tmpfile)) {
+		free(tmpfile);
+		return -1;
+	}
 	free(tmpfile);
 
 	if (!oidcmp(&old_oid, &new_oid))
@@ -310,7 +349,7 @@
 	return replace_object_oid(object_ref, &old_oid, "replacement", &new_oid, force);
 }
 
-static void replace_parents(struct strbuf *buf, int argc, const char **argv)
+static int replace_parents(struct strbuf *buf, int argc, const char **argv)
 {
 	struct strbuf new_parents = STRBUF_INIT;
 	const char *parent_start, *parent_end;
@@ -327,9 +366,15 @@
 	/* prepare new parents */
 	for (i = 0; i < argc; i++) {
 		struct object_id oid;
-		if (get_oid(argv[i], &oid) < 0)
-			die(_("Not a valid object name: '%s'"), argv[i]);
-		lookup_commit_or_die(&oid, argv[i]);
+		if (get_oid(argv[i], &oid) < 0) {
+			strbuf_release(&new_parents);
+			return error(_("Not a valid object name: '%s'"),
+				     argv[i]);
+		}
+		if (!lookup_commit_reference(&oid)) {
+			strbuf_release(&new_parents);
+			return error(_("could not parse %s"), argv[i]);
+		}
 		strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&oid));
 	}
 
@@ -338,6 +383,7 @@
 		      new_parents.buf, new_parents.len);
 
 	strbuf_release(&new_parents);
+	return 0;
 }
 
 struct check_mergetag_data {
@@ -345,7 +391,7 @@
 	const char **argv;
 };
 
-static void check_one_mergetag(struct commit *commit,
+static int check_one_mergetag(struct commit *commit,
 			       struct commit_extra_header *extra,
 			       void *data)
 {
@@ -358,33 +404,35 @@
 	hash_object_file(extra->value, extra->len, type_name(OBJ_TAG), &tag_oid);
 	tag = lookup_tag(&tag_oid);
 	if (!tag)
-		die(_("bad mergetag in commit '%s'"), ref);
+		return error(_("bad mergetag in commit '%s'"), ref);
 	if (parse_tag_buffer(tag, extra->value, extra->len))
-		die(_("malformed mergetag in commit '%s'"), ref);
+		return error(_("malformed mergetag in commit '%s'"), ref);
 
 	/* iterate over new parents */
 	for (i = 1; i < mergetag_data->argc; i++) {
 		struct object_id oid;
 		if (get_oid(mergetag_data->argv[i], &oid) < 0)
-			die(_("Not a valid object name: '%s'"), mergetag_data->argv[i]);
+			return error(_("Not a valid object name: '%s'"),
+				     mergetag_data->argv[i]);
 		if (!oidcmp(&tag->tagged->oid, &oid))
-			return; /* found */
+			return 0; /* found */
 	}
 
-	die(_("original commit '%s' contains mergetag '%s' that is discarded; "
-	      "use --edit instead of --graft"), ref, oid_to_hex(&tag_oid));
+	return error(_("original commit '%s' contains mergetag '%s' that is "
+		       "discarded; use --edit instead of --graft"), ref,
+		     oid_to_hex(&tag_oid));
 }
 
-static void check_mergetags(struct commit *commit, int argc, const char **argv)
+static int check_mergetags(struct commit *commit, int argc, const char **argv)
 {
 	struct check_mergetag_data mergetag_data;
 
 	mergetag_data.argc = argc;
 	mergetag_data.argv = argv;
-	for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
+	return for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
 }
 
-static int create_graft(int argc, const char **argv, int force)
+static int create_graft(int argc, const char **argv, int force, int gentle)
 {
 	struct object_id old_oid, new_oid;
 	const char *old_ref = argv[0];
@@ -394,33 +442,81 @@
 	unsigned long size;
 
 	if (get_oid(old_ref, &old_oid) < 0)
-		die(_("Not a valid object name: '%s'"), old_ref);
-	commit = lookup_commit_or_die(&old_oid, old_ref);
+		return error(_("Not a valid object name: '%s'"), old_ref);
+	commit = lookup_commit_reference(&old_oid);
+	if (!commit)
+		return error(_("could not parse %s"), old_ref);
 
 	buffer = get_commit_buffer(commit, &size);
 	strbuf_add(&buf, buffer, size);
 	unuse_commit_buffer(commit, buffer);
 
-	replace_parents(&buf, argc - 1, &argv[1]);
+	if (replace_parents(&buf, argc - 1, &argv[1]) < 0) {
+		strbuf_release(&buf);
+		return -1;
+	}
 
 	if (remove_signature(&buf)) {
 		warning(_("the original commit '%s' has a gpg signature."), old_ref);
 		warning(_("the signature will be removed in the replacement commit!"));
 	}
 
-	check_mergetags(commit, argc, argv);
+	if (check_mergetags(commit, argc, argv)) {
+		strbuf_release(&buf);
+		return -1;
+	}
 
-	if (write_object_file(buf.buf, buf.len, commit_type, &new_oid))
-		die(_("could not write replacement commit for: '%s'"), old_ref);
+	if (write_object_file(buf.buf, buf.len, commit_type, &new_oid)) {
+		strbuf_release(&buf);
+		return error(_("could not write replacement commit for: '%s'"),
+			     old_ref);
+	}
 
 	strbuf_release(&buf);
 
-	if (!oidcmp(&old_oid, &new_oid))
+	if (!oidcmp(&old_oid, &new_oid)) {
+		if (gentle) {
+			warning("graft for '%s' unnecessary", oid_to_hex(&old_oid));
+			return 0;
+		}
 		return error("new commit is the same as the old one: '%s'", oid_to_hex(&old_oid));
+	}
 
 	return replace_object_oid(old_ref, &old_oid, "replacement", &new_oid, force);
 }
 
+static int convert_graft_file(int force)
+{
+	const char *graft_file = get_graft_file();
+	FILE *fp = fopen_or_warn(graft_file, "r");
+	struct strbuf buf = STRBUF_INIT, err = STRBUF_INIT;
+	struct argv_array args = ARGV_ARRAY_INIT;
+
+	if (!fp)
+		return -1;
+
+	while (strbuf_getline(&buf, fp) != EOF) {
+		if (*buf.buf == '#')
+			continue;
+
+		argv_array_split(&args, buf.buf);
+		if (args.argc && create_graft(args.argc, args.argv, force, 1))
+			strbuf_addf(&err, "\n\t%s", buf.buf);
+		argv_array_clear(&args);
+	}
+	fclose(fp);
+
+	strbuf_release(&buf);
+
+	if (!err.len)
+		return unlink_or_warn(graft_file);
+
+	warning(_("could not convert the following graft(s):\n%s"), err.buf);
+	strbuf_release(&err);
+
+	return -1;
+}
+
 int cmd_replace(int argc, const char **argv, const char *prefix)
 {
 	int force = 0;
@@ -432,6 +528,7 @@
 		MODE_DELETE,
 		MODE_EDIT,
 		MODE_GRAFT,
+		MODE_CONVERT_GRAFT_FILE,
 		MODE_REPLACE
 	} cmdmode = MODE_UNSPECIFIED;
 	struct option options[] = {
@@ -439,6 +536,7 @@
 		OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
 		OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
 		OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
+		OPT_CMDMODE(0, "convert-graft-file", &cmdmode, N_("convert existing graft file"), MODE_CONVERT_GRAFT_FILE),
 		OPT_BOOL_F('f', "force", &force, N_("replace the ref if it exists"),
 			   PARSE_OPT_NOCOMPLETE),
 		OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
@@ -461,7 +559,8 @@
 	if (force &&
 	    cmdmode != MODE_REPLACE &&
 	    cmdmode != MODE_EDIT &&
-	    cmdmode != MODE_GRAFT)
+	    cmdmode != MODE_GRAFT &&
+	    cmdmode != MODE_CONVERT_GRAFT_FILE)
 		usage_msg_opt("-f only makes sense when writing a replacement",
 			      git_replace_usage, options);
 
@@ -492,7 +591,13 @@
 		if (argc < 1)
 			usage_msg_opt("-g needs at least one argument",
 				      git_replace_usage, options);
-		return create_graft(argc, argv, force);
+		return create_graft(argc, argv, force, 0);
+
+	case MODE_CONVERT_GRAFT_FILE:
+		if (argc != 0)
+			usage_msg_opt("--convert-graft-file takes no argument",
+				      git_replace_usage, options);
+		return !!convert_graft_file(force);
 
 	case MODE_LIST:
 		if (argc > 1)
@@ -501,6 +606,6 @@
 		return list_replace_refs(argv[0], format);
 
 	default:
-		die("BUG: invalid cmdmode %d", (int)cmdmode);
+		BUG("invalid cmdmode %d", (int)cmdmode);
 	}
 }
diff --git a/builtin/reset.c b/builtin/reset.c
index 7f1c3f0..a862c70 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -314,7 +314,7 @@
 	unborn = !strcmp(rev, "HEAD") && get_oid("HEAD", &oid);
 	if (unborn) {
 		/* reset on unborn branch: treat as reset to empty tree */
-		hashcpy(oid.hash, EMPTY_TREE_SHA1_BIN);
+		oidcpy(&oid, the_hash_algo->empty_tree);
 	} else if (!pathspec.nr) {
 		struct commit *commit;
 		if (get_oid_committish(rev, &oid))
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 36b2087..4f49e96 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -282,6 +282,10 @@
 			struct commit *a, *b;
 			a = lookup_commit_reference(&start_oid);
 			b = lookup_commit_reference(&end_oid);
+			if (!a || !b) {
+				*dotdot = '.';
+				return 0;
+			}
 			exclude = get_merge_bases(a, b);
 			while (exclude) {
 				struct commit *commit = pop_commit(&exclude);
@@ -328,12 +332,12 @@
 		return 0;
 
 	*dotdot = 0;
-	if (get_oid_committish(arg, &oid)) {
+	if (get_oid_committish(arg, &oid) ||
+	    !(commit = lookup_commit_reference(&oid))) {
 		*dotdot = '^';
 		return 0;
 	}
 
-	commit = lookup_commit_reference(&oid);
 	if (exclude_parent &&
 	    exclude_parent > commit_list_count(commit->parents)) {
 		*dotdot = '^';
@@ -887,8 +891,8 @@
 				if (read_cache() < 0)
 					die(_("Could not read the index"));
 				if (the_index.split_index) {
-					const unsigned char *sha1 = the_index.split_index->base_sha1;
-					const char *path = git_path("sharedindex.%s", sha1_to_hex(sha1));
+					const struct object_id *oid = &the_index.split_index->base_oid;
+					const char *path = git_path("sharedindex.%s", oid_to_hex(oid));
 					strbuf_reset(&buf);
 					puts(relative_path(path, prefix, &buf));
 				}
diff --git a/builtin/rm.c b/builtin/rm.c
index 5b6fc7e..65b448e 100644
--- a/builtin/rm.c
+++ b/builtin/rm.c
@@ -233,8 +233,6 @@
 	return errs;
 }
 
-static struct lock_file lock_file;
-
 static int show_only = 0, force = 0, index_only = 0, recursive = 0, quiet = 0;
 static int ignore_unmatch = 0;
 
@@ -251,6 +249,7 @@
 
 int cmd_rm(int argc, const char **argv, const char *prefix)
 {
+	struct lock_file lock_file = LOCK_INIT;
 	int i;
 	struct pathspec pathspec;
 	char *seen;
diff --git a/builtin/send-pack.c b/builtin/send-pack.c
index fc4f0bb..4923b10 100644
--- a/builtin/send-pack.c
+++ b/builtin/send-pack.c
@@ -14,6 +14,7 @@
 #include "sha1-array.h"
 #include "gpg-interface.h"
 #include "gettext.h"
+#include "protocol.h"
 
 static const char * const send_pack_usage[] = {
 	N_("git send-pack [--all | --mirror] [--dry-run] [--force] "
@@ -125,8 +126,7 @@
 
 int cmd_send_pack(int argc, const char **argv, const char *prefix)
 {
-	int i, nr_refspecs = 0;
-	const char **refspecs = NULL;
+	struct refspec rs = REFSPEC_INIT_PUSH;
 	const char *remote_name = NULL;
 	struct remote *remote = NULL;
 	const char *dest = NULL;
@@ -154,6 +154,7 @@
 	int progress = -1;
 	int from_stdin = 0;
 	struct push_cas_option cas = {0};
+	struct packet_reader reader;
 
 	struct option options[] = {
 		OPT__VERBOSITY(&verbose),
@@ -187,8 +188,7 @@
 	argc = parse_options(argc, argv, prefix, options, send_pack_usage, 0);
 	if (argc > 0) {
 		dest = argv[0];
-		refspecs = (const char **)(argv + 1);
-		nr_refspecs = argc - 1;
+		refspec_appendn(&rs, argv + 1, argc - 1);
 	}
 
 	if (!dest)
@@ -207,31 +207,23 @@
 	args.push_options = push_options.nr ? &push_options : NULL;
 
 	if (from_stdin) {
-		struct argv_array all_refspecs = ARGV_ARRAY_INIT;
-
-		for (i = 0; i < nr_refspecs; i++)
-			argv_array_push(&all_refspecs, refspecs[i]);
-
 		if (args.stateless_rpc) {
 			const char *buf;
 			while ((buf = packet_read_line(0, NULL)))
-				argv_array_push(&all_refspecs, buf);
+				refspec_append(&rs, buf);
 		} else {
 			struct strbuf line = STRBUF_INIT;
 			while (strbuf_getline(&line, stdin) != EOF)
-				argv_array_push(&all_refspecs, line.buf);
+				refspec_append(&rs, line.buf);
 			strbuf_release(&line);
 		}
-
-		refspecs = all_refspecs.argv;
-		nr_refspecs = all_refspecs.argc;
 	}
 
 	/*
 	 * --all and --mirror are incompatible; neither makes sense
 	 * with any refspecs.
 	 */
-	if ((nr_refspecs > 0 && (send_all || args.send_mirror)) ||
+	if ((rs.nr > 0 && (send_all || args.send_mirror)) ||
 	    (send_all && args.send_mirror))
 		usage_with_options(send_pack_usage, options);
 
@@ -256,10 +248,22 @@
 			args.verbose ? CONNECT_VERBOSE : 0);
 	}
 
-	get_remote_heads(fd[0], NULL, 0, &remote_refs, REF_NORMAL,
-			 &extra_have, &shallow);
+	packet_reader_init(&reader, fd[0], NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_GENTLE_ON_EOF);
 
-	transport_verify_remote_names(nr_refspecs, refspecs);
+	switch (discover_version(&reader)) {
+	case protocol_v2:
+		die("support for protocol v2 not implemented yet");
+		break;
+	case protocol_v1:
+	case protocol_v0:
+		get_remote_heads(&reader, &remote_refs, REF_NORMAL,
+				 &extra_have, &shallow);
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
+	}
 
 	local_refs = get_local_heads();
 
@@ -271,7 +275,7 @@
 		flags |= MATCH_REFS_MIRROR;
 
 	/* match them up */
-	if (match_push_refs(local_refs, &remote_refs, nr_refspecs, refspecs, flags))
+	if (match_push_refs(local_refs, &remote_refs, &rs, flags))
 		return -1;
 
 	if (!is_empty_cas(&cas))
diff --git a/builtin/serve.c b/builtin/serve.c
new file mode 100644
index 0000000..d3fd240
--- /dev/null
+++ b/builtin/serve.c
@@ -0,0 +1,30 @@
+#include "cache.h"
+#include "builtin.h"
+#include "parse-options.h"
+#include "serve.h"
+
+static char const * const serve_usage[] = {
+	N_("git serve [<options>]"),
+	NULL
+};
+
+int cmd_serve(int argc, const char **argv, const char *prefix)
+{
+	struct serve_options opts = SERVE_OPTIONS_INIT;
+
+	struct option options[] = {
+		OPT_BOOL(0, "stateless-rpc", &opts.stateless_rpc,
+			 N_("quit after a single request/response exchange")),
+		OPT_BOOL(0, "advertise-capabilities", &opts.advertise_capabilities,
+			 N_("exit immediately after advertising capabilities")),
+		OPT_END()
+	};
+
+	/* ignore all unknown cmdline switches for now */
+	argc = parse_options(argc, argv, prefix, options, serve_usage,
+			     PARSE_OPT_KEEP_DASHDASH |
+			     PARSE_OPT_KEEP_UNKNOWN);
+	serve(&opts);
+
+	return 0;
+}
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index a404df3..bd250ca 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -12,6 +12,7 @@
 #include "run-command.h"
 #include "remote.h"
 #include "refs.h"
+#include "refspec.h"
 #include "connect.h"
 #include "revision.h"
 #include "diffcore.h"
@@ -455,7 +456,7 @@
 
 	displaypath = get_submodule_displaypath(path, prefix);
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(the_repository, &null_oid, path);
 
 	if (!sub)
 		die(_("No url found for submodule path '%s' in .gitmodules"),
@@ -596,8 +597,12 @@
 
 	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
 
-	if (state == ' ' || state == '+')
-		printf(" (%s)", compute_rev_name(path, oid_to_hex(oid)));
+	if (state == ' ' || state == '+') {
+		const char *name = compute_rev_name(path, oid_to_hex(oid));
+
+		if (name)
+			printf(" (%s)", name);
+	}
 
 	printf("\n");
 }
@@ -622,7 +627,7 @@
 	struct rev_info rev;
 	int diff_files_result;
 
-	if (!submodule_from_path(&null_oid, path))
+	if (!submodule_from_path(the_repository, &null_oid, path))
 		die(_("no submodule mapping found in .gitmodules for path '%s'"),
 		      path);
 
@@ -746,7 +751,7 @@
 	if (argc != 2)
 		usage(_("git submodule--helper name <path>"));
 
-	sub = submodule_from_path(&null_oid, argv[1]);
+	sub = submodule_from_path(the_repository, &null_oid, argv[1]);
 
 	if (!sub)
 		die(_("no submodule mapping found in .gitmodules for path '%s'"),
@@ -777,7 +782,7 @@
 	if (!is_submodule_active(the_repository, path))
 		return;
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(the_repository, &null_oid, path);
 
 	if (sub && sub->url) {
 		if (starts_with_dot_dot_slash(sub->url) ||
@@ -930,7 +935,7 @@
 	struct strbuf sb_config = STRBUF_INIT;
 	char *sub_git_dir = xstrfmt("%s/.git", path);
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(the_repository, &null_oid, path);
 
 	if (!sub || !sub->name)
 		goto cleanup;
@@ -1061,7 +1066,7 @@
 }
 
 static int clone_submodule(const char *path, const char *gitdir, const char *url,
-			   const char *depth, struct string_list *reference,
+			   const char *depth, struct string_list *reference, int dissociate,
 			   int quiet, int progress)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
@@ -1080,6 +1085,8 @@
 			argv_array_pushl(&cp.args, "--reference",
 					 item->string, NULL);
 	}
+	if (dissociate)
+		argv_array_push(&cp.args, "--dissociate");
 	if (gitdir && *gitdir)
 		argv_array_pushl(&cp.args, "--separate-git-dir", gitdir, NULL);
 
@@ -1195,6 +1202,7 @@
 	char *p, *path = NULL, *sm_gitdir;
 	struct strbuf sb = STRBUF_INIT;
 	struct string_list reference = STRING_LIST_INIT_NODUP;
+	int dissociate = 0;
 	char *sm_alternate = NULL, *error_strategy = NULL;
 
 	struct option module_clone_options[] = {
@@ -1213,6 +1221,8 @@
 		OPT_STRING_LIST(0, "reference", &reference,
 			   N_("repo"),
 			   N_("reference repository")),
+		OPT_BOOL(0, "dissociate", &dissociate,
+			   N_("use --reference only while cloning")),
 		OPT_STRING(0, "depth", &depth,
 			   N_("string"),
 			   N_("depth for shallow clones")),
@@ -1252,7 +1262,7 @@
 
 		prepare_possible_alternates(name, &reference);
 
-		if (clone_submodule(path, sm_gitdir, url, depth, &reference,
+		if (clone_submodule(path, sm_gitdir, url, depth, &reference, dissociate,
 				    quiet, progress))
 			die(_("clone of '%s' into submodule path '%s' failed"),
 			    url, path);
@@ -1264,8 +1274,7 @@
 		strbuf_reset(&sb);
 	}
 
-	/* Connect module worktree and git dir */
-	connect_work_tree_and_git_dir(path, sm_gitdir);
+	connect_work_tree_and_git_dir(path, sm_gitdir, 0);
 
 	p = git_pathdup_submodule(path, "config");
 	if (!p)
@@ -1305,6 +1314,7 @@
 	int quiet;
 	int recommend_shallow;
 	struct string_list references;
+	int dissociate;
 	const char *depth;
 	const char *recursive_prefix;
 	const char *prefix;
@@ -1320,7 +1330,7 @@
 	int failed_clones_nr, failed_clones_alloc;
 };
 #define SUBMODULE_UPDATE_CLONE_INIT {0, MODULE_LIST_INIT, 0, \
-	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, \
+	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, 0, \
 	NULL, NULL, NULL, \
 	STRING_LIST_INIT_DUP, 0, NULL, 0, 0}
 
@@ -1372,7 +1382,7 @@
 		goto cleanup;
 	}
 
-	sub = submodule_from_path(&null_oid, ce->name);
+	sub = submodule_from_path(the_repository, &null_oid, ce->name);
 
 	if (suc->recursive_prefix)
 		displaypath = relative_path(suc->recursive_prefix,
@@ -1447,6 +1457,8 @@
 		for_each_string_list_item(item, &suc->references)
 			argv_array_pushl(&child->args, "--reference", item->string, NULL);
 	}
+	if (suc->dissociate)
+		argv_array_push(&child->args, "--dissociate");
 	if (suc->depth)
 		argv_array_push(&child->args, suc->depth);
 
@@ -1580,6 +1592,8 @@
 			   N_("rebase, merge, checkout or none")),
 		OPT_STRING_LIST(0, "reference", &suc.references, N_("repo"),
 			   N_("reference repository")),
+		OPT_BOOL(0, "dissociate", &suc.dissociate,
+			   N_("use --reference only while cloning")),
 		OPT_STRING(0, "depth", &suc.depth, "<depth>",
 			   N_("Create a shallow clone truncated to the "
 			      "specified number of revisions")),
@@ -1655,7 +1669,7 @@
 	const char *branch = NULL;
 	char *key;
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(the_repository, &null_oid, path);
 	if (!sub)
 		return NULL;
 
@@ -1740,13 +1754,14 @@
 
 	/* Check the refspec */
 	if (argc > 2) {
-		int i, refspec_nr = argc - 2;
+		int i;
 		struct ref *local_refs = get_local_heads();
-		struct refspec *refspec = parse_push_refspec(refspec_nr,
-							     argv + 2);
+		struct refspec refspec = REFSPEC_INIT_PUSH;
 
-		for (i = 0; i < refspec_nr; i++) {
-			struct refspec *rs = refspec + i;
+		refspec_appendn(&refspec, argv + 2, argc - 2);
+
+		for (i = 0; i < refspec.nr; i++) {
+			const struct refspec_item *rs = &refspec.items[i];
 
 			if (rs->pattern || rs->matching)
 				continue;
@@ -1773,7 +1788,7 @@
 				    rs->src);
 			}
 		}
-		free_refspec(refspec_nr, refspec);
+		refspec_clear(&refspec);
 	}
 	free(head);
 
@@ -1822,6 +1837,29 @@
 	return !is_submodule_active(the_repository, argv[1]);
 }
 
+/*
+ * Exit non-zero if any of the submodule names given on the command line is
+ * invalid. If no names are given, filter stdin to print only valid names
+ * (which is primarily intended for testing).
+ */
+static int check_name(int argc, const char **argv, const char *prefix)
+{
+	if (argc > 1) {
+		while (*++argv) {
+			if (check_submodule_name(*argv) < 0)
+				return 1;
+		}
+	} else {
+		struct strbuf buf = STRBUF_INIT;
+		while (strbuf_getline(&buf, stdin) != EOF) {
+			if (!check_submodule_name(buf.buf))
+				printf("%s\n", buf.buf);
+		}
+		strbuf_release(&buf);
+	}
+	return 0;
+}
+
 #define SUPPORT_SUPER_PREFIX (1<<0)
 
 struct cmd_struct {
@@ -1847,6 +1885,7 @@
 	{"push-check", push_check, 0},
 	{"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
 	{"is-active", is_active, 0},
+	{"check-name", check_name, 0},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
diff --git a/builtin/tag.c b/builtin/tag.c
index 46a5c6a..5d0dd11 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -212,7 +212,7 @@
 	struct strbuf header = STRBUF_INIT;
 	char *path = NULL;
 
-	type = oid_object_info(object, NULL);
+	type = oid_object_info(the_repository, object, NULL);
 	if (type <= OBJ_NONE)
 	    die(_("bad object type."));
 
@@ -298,7 +298,7 @@
 	}
 
 	strbuf_addstr(sb, " (");
-	type = oid_object_info(oid, NULL);
+	type = oid_object_info(the_repository, oid, NULL);
 	switch (type) {
 	default:
 		strbuf_addstr(sb, "object of unknown type");
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
index b7755c6..6e81ca8 100644
--- a/builtin/unpack-objects.c
+++ b/builtin/unpack-objects.c
@@ -199,7 +199,7 @@
 
 	if (!(obj->flags & FLAG_OPEN)) {
 		unsigned long size;
-		int type = oid_object_info(&obj->oid, &size);
+		int type = oid_object_info(the_repository, &obj->oid, &size);
 		if (type != obj->type || type <= 0)
 			die("object of unexpected type");
 		obj->flags |= FLAG_WRITTEN;
@@ -210,7 +210,7 @@
 	if (!obj_buf)
 		die("Whoops! Cannot find object '%s'", oid_to_hex(&obj->oid));
 	if (fsck_object(obj, obj_buf->buffer, obj_buf->size, &fsck_options))
-		die("Error in object");
+		die("fsck error in packed object");
 	fsck_options.walk = check_object;
 	if (fsck_walk(obj, NULL, &fsck_options))
 		die("Error on reachable objects of %s", oid_to_hex(&obj->oid));
@@ -572,8 +572,11 @@
 	unpack_all();
 	the_hash_algo->update_fn(&ctx, buffer, offset);
 	the_hash_algo->final_fn(oid.hash, &ctx);
-	if (strict)
+	if (strict) {
 		write_rest();
+		if (fsck_finish(&fsck_options))
+			die(_("fsck error in pack objects"));
+	}
 	if (hashcmp(fill(the_hash_algo->rawsz), oid.hash))
 		die("final sha1 did not match");
 	use(the_hash_algo->rawsz);
diff --git a/builtin/update-index.c b/builtin/update-index.c
index 10d070a..a8709a2 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -364,10 +364,9 @@
 	return error("%s: is a directory - add files inside instead", path);
 }
 
-static int process_path(const char *path)
+static int process_path(const char *path, struct stat *st, int stat_errno)
 {
 	int pos, len;
-	struct stat st;
 	const struct cache_entry *ce;
 
 	len = strlen(path);
@@ -391,13 +390,13 @@
 	 * First things first: get the stat information, to decide
 	 * what to do about the pathname!
 	 */
-	if (lstat(path, &st) < 0)
-		return process_lstat_error(path, errno);
+	if (stat_errno)
+		return process_lstat_error(path, stat_errno);
 
-	if (S_ISDIR(st.st_mode))
-		return process_directory(path, len, &st);
+	if (S_ISDIR(st->st_mode))
+		return process_directory(path, len, st);
 
-	return add_one_path(ce, path, len, &st);
+	return add_one_path(ce, path, len, st);
 }
 
 static int add_cacheinfo(unsigned int mode, const struct object_id *oid,
@@ -406,7 +405,7 @@
 	int size, len, option;
 	struct cache_entry *ce;
 
-	if (!verify_path(path))
+	if (!verify_path(path, mode))
 		return error("Invalid path '%s'", path);
 
 	len = strlen(path);
@@ -449,7 +448,18 @@
 
 static void update_one(const char *path)
 {
-	if (!verify_path(path)) {
+	int stat_errno = 0;
+	struct stat st;
+
+	if (mark_valid_only || mark_skip_worktree_only || force_remove ||
+	    mark_fsmonitor_only)
+		st.st_mode = 0;
+	else if (lstat(path, &st) < 0) {
+		st.st_mode = 0;
+		stat_errno = errno;
+	} /* else stat is valid */
+
+	if (!verify_path(path, st.st_mode)) {
 		fprintf(stderr, "Ignoring path %s\n", path);
 		return;
 	}
@@ -475,7 +485,7 @@
 		report("remove '%s'", path);
 		return;
 	}
-	if (process_path(path))
+	if (process_path(path, &st, stat_errno))
 		die("Unable to process path %s", path);
 	report("add '%s'", path);
 }
@@ -545,7 +555,7 @@
 			path_name = uq.buf;
 		}
 
-		if (!verify_path(path_name)) {
+		if (!verify_path(path_name, mode)) {
 			fprintf(stderr, "Ignoring path %s\n", path_name);
 			continue;
 		}
@@ -1164,7 +1174,7 @@
 		report(_("Untracked cache enabled for '%s'"), get_git_work_tree());
 		break;
 	default:
-		die("BUG: bad untracked_cache value: %d", untracked_cache);
+		BUG("bad untracked_cache value: %d", untracked_cache);
 	}
 
 	if (fsmonitor > 0) {
diff --git a/builtin/upload-pack.c b/builtin/upload-pack.c
new file mode 100644
index 0000000..decde5a
--- /dev/null
+++ b/builtin/upload-pack.c
@@ -0,0 +1,74 @@
+#include "cache.h"
+#include "builtin.h"
+#include "exec-cmd.h"
+#include "pkt-line.h"
+#include "parse-options.h"
+#include "protocol.h"
+#include "upload-pack.h"
+#include "serve.h"
+
+static const char * const upload_pack_usage[] = {
+	N_("git upload-pack [<options>] <dir>"),
+	NULL
+};
+
+int cmd_upload_pack(int argc, const char **argv, const char *prefix)
+{
+	const char *dir;
+	int strict = 0;
+	struct upload_pack_options opts = { 0 };
+	struct serve_options serve_opts = SERVE_OPTIONS_INIT;
+	struct option options[] = {
+		OPT_BOOL(0, "stateless-rpc", &opts.stateless_rpc,
+			 N_("quit after a single request/response exchange")),
+		OPT_BOOL(0, "advertise-refs", &opts.advertise_refs,
+			 N_("exit immediately after initial ref advertisement")),
+		OPT_BOOL(0, "strict", &strict,
+			 N_("do not try <directory>/.git/ if <directory> is no Git directory")),
+		OPT_INTEGER(0, "timeout", &opts.timeout,
+			    N_("interrupt transfer after <n> seconds of inactivity")),
+		OPT_END()
+	};
+
+	packet_trace_identity("upload-pack");
+	check_replace_refs = 0;
+
+	argc = parse_options(argc, argv, NULL, options, upload_pack_usage, 0);
+
+	if (argc != 1)
+		usage_with_options(upload_pack_usage, options);
+
+	if (opts.timeout)
+		opts.daemon_mode = 1;
+
+	setup_path();
+
+	dir = argv[0];
+
+	if (!enter_repo(dir, strict))
+		die("'%s' does not appear to be a git repository", dir);
+
+	switch (determine_protocol_version_server()) {
+	case protocol_v2:
+		serve_opts.advertise_capabilities = opts.advertise_refs;
+		serve_opts.stateless_rpc = opts.stateless_rpc;
+		serve(&serve_opts);
+		break;
+	case protocol_v1:
+		/*
+		 * v1 is just the original protocol with a version string,
+		 * so just fall through after writing the version string.
+		 */
+		if (opts.advertise_refs || !opts.stateless_rpc)
+			packet_write_fmt(1, "version 1\n");
+
+		/* fallthrough */
+	case protocol_v0:
+		upload_pack(&opts);
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
+	}
+
+	return 0;
+}
diff --git a/builtin/worktree.c b/builtin/worktree.c
index 40a438e..5c7d2bb 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -29,8 +29,6 @@
 	int detach;
 	int checkout;
 	int keep_locked;
-	const char *new_branch;
-	int force_new_branch;
 };
 
 static int show_only;
@@ -298,8 +296,6 @@
 	strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
 	write_file(sb.buf, "../..");
 
-	fprintf_ln(stderr, _("Preparing %s (identifier %s)"), path, name);
-
 	argv_array_pushf(&child_env, "%s=%s", GIT_DIR_ENVIRONMENT, sb_git.buf);
 	argv_array_pushf(&child_env, "%s=%s", GIT_WORK_TREE_ENVIRONMENT, path);
 	cp.git_cmd = 1;
@@ -366,18 +362,75 @@
 	return ret;
 }
 
+static void print_preparing_worktree_line(int detach,
+					  const char *branch,
+					  const char *new_branch,
+					  int force_new_branch)
+{
+	if (force_new_branch) {
+		struct commit *commit = lookup_commit_reference_by_name(new_branch);
+		if (!commit)
+			printf_ln(_("Preparing worktree (new branch '%s')"), new_branch);
+		else
+			printf_ln(_("Preparing worktree (resetting branch '%s'; was at %s)"),
+				  new_branch,
+				  find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
+	} else if (new_branch) {
+		printf_ln(_("Preparing worktree (new branch '%s')"), new_branch);
+	} else {
+		struct strbuf s = STRBUF_INIT;
+		if (!detach && !strbuf_check_branch_ref(&s, branch) &&
+		    ref_exists(s.buf))
+			printf_ln(_("Preparing worktree (checking out '%s')"),
+				  branch);
+		else {
+			struct commit *commit = lookup_commit_reference_by_name(branch);
+			if (!commit)
+				die(_("invalid reference: %s"), branch);
+			printf_ln(_("Preparing worktree (detached HEAD %s)"),
+				  find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
+		}
+		strbuf_release(&s);
+	}
+}
+
+static const char *dwim_branch(const char *path, const char **new_branch)
+{
+	int n;
+	const char *s = worktree_basename(path, &n);
+	const char *branchname = xstrndup(s, n);
+	struct strbuf ref = STRBUF_INIT;
+
+	UNLEAK(branchname);
+	if (!strbuf_check_branch_ref(&ref, branchname) &&
+	    ref_exists(ref.buf)) {
+		strbuf_release(&ref);
+		return branchname;
+	}
+
+	*new_branch = branchname;
+	if (guess_remote) {
+		struct object_id oid;
+		const char *remote =
+			unique_tracking_name(*new_branch, &oid);
+		return remote;
+	}
+	return NULL;
+}
+
 static int add(int ac, const char **av, const char *prefix)
 {
 	struct add_opts opts;
 	const char *new_branch_force = NULL;
 	char *path;
 	const char *branch;
+	const char *new_branch = NULL;
 	const char *opt_track = NULL;
 	struct option options[] = {
 		OPT__FORCE(&opts.force,
 			   N_("checkout <branch> even if already checked out in other worktree"),
 			   PARSE_OPT_NOCOMPLETE),
-		OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
+		OPT_STRING('b', NULL, &new_branch, N_("branch"),
 			   N_("create a new branch")),
 		OPT_STRING('B', NULL, &new_branch_force, N_("branch"),
 			   N_("create or reset a branch")),
@@ -395,7 +448,7 @@
 	memset(&opts, 0, sizeof(opts));
 	opts.checkout = 1;
 	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
-	if (!!opts.detach + !!opts.new_branch + !!new_branch_force > 1)
+	if (!!opts.detach + !!new_branch + !!new_branch_force > 1)
 		die(_("-b, -B, and --detach are mutually exclusive"));
 	if (ac < 1 || ac > 2)
 		usage_with_options(worktree_usage, options);
@@ -406,33 +459,25 @@
 	if (!strcmp(branch, "-"))
 		branch = "@{-1}";
 
-	opts.force_new_branch = !!new_branch_force;
-	if (opts.force_new_branch) {
+	if (new_branch_force) {
 		struct strbuf symref = STRBUF_INIT;
 
-		opts.new_branch = new_branch_force;
+		new_branch = new_branch_force;
 
 		if (!opts.force &&
-		    !strbuf_check_branch_ref(&symref, opts.new_branch) &&
+		    !strbuf_check_branch_ref(&symref, new_branch) &&
 		    ref_exists(symref.buf))
 			die_if_checked_out(symref.buf, 0);
 		strbuf_release(&symref);
 	}
 
-	if (ac < 2 && !opts.new_branch && !opts.detach) {
-		int n;
-		const char *s = worktree_basename(path, &n);
-		opts.new_branch = xstrndup(s, n);
-		if (guess_remote) {
-			struct object_id oid;
-			const char *remote =
-				unique_tracking_name(opts.new_branch, &oid);
-			if (remote)
-				branch = remote;
-		}
+	if (ac < 2 && !new_branch && !opts.detach) {
+		const char *s = dwim_branch(path, &new_branch);
+		if (s)
+			branch = s;
 	}
 
-	if (ac == 2 && !opts.new_branch && !opts.detach) {
+	if (ac == 2 && !new_branch && !opts.detach) {
 		struct object_id oid;
 		struct commit *commit;
 		const char *remote;
@@ -441,25 +486,27 @@
 		if (!commit) {
 			remote = unique_tracking_name(branch, &oid);
 			if (remote) {
-				opts.new_branch = branch;
+				new_branch = branch;
 				branch = remote;
 			}
 		}
 	}
 
-	if (opts.new_branch) {
+	print_preparing_worktree_line(opts.detach, branch, new_branch, !!new_branch_force);
+
+	if (new_branch) {
 		struct child_process cp = CHILD_PROCESS_INIT;
 		cp.git_cmd = 1;
 		argv_array_push(&cp.args, "branch");
-		if (opts.force_new_branch)
+		if (new_branch_force)
 			argv_array_push(&cp.args, "--force");
-		argv_array_push(&cp.args, opts.new_branch);
+		argv_array_push(&cp.args, new_branch);
 		argv_array_push(&cp.args, branch);
 		if (opt_track)
 			argv_array_push(&cp.args, opt_track);
 		if (run_command(&cp))
 			return -1;
-		branch = opts.new_branch;
+		branch = new_branch;
 	} else if (opt_track) {
 		die(_("--[no-]track can only be used if a new branch is created"));
 	}
@@ -783,8 +830,9 @@
 {
 	int force = 0;
 	struct option options[] = {
-		OPT_BOOL(0, "force", &force,
-			 N_("force removing even if the worktree is dirty")),
+		OPT__FORCE(&force,
+			 N_("force removing even if the worktree is dirty"),
+			 PARSE_OPT_NOCOMPLETE),
 		OPT_END()
 	};
 	struct worktree **worktrees, *wt;
diff --git a/bulk-checkin.c b/bulk-checkin.c
index de1f404..b7e131c 100644
--- a/bulk-checkin.c
+++ b/bulk-checkin.c
@@ -36,9 +36,9 @@
 		unlink(state->pack_tmp_name);
 		goto clear_exit;
 	} else if (state->nr_written == 1) {
-		hashclose(state->f, oid.hash, CSUM_FSYNC);
+		finalize_hashfile(state->f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
 	} else {
-		int fd = hashclose(state->f, oid.hash, 0);
+		int fd = finalize_hashfile(state->f, oid.hash, 0);
 		fixup_pack_header_footer(fd, oid.hash, state->pack_tmp_name,
 					 state->nr_written, oid.hash,
 					 state->offset);
@@ -230,7 +230,7 @@
 		 * pack, and write into it.
 		 */
 		if (!idx)
-			die("BUG: should not happen");
+			BUG("should not happen");
 		hashfile_truncate(state->f, &checkpoint);
 		state->offset = checkpoint.offset;
 		finish_bulk_checkin(state);
diff --git a/bundle.c b/bundle.c
index 902c9b5..160bbfd 100644
--- a/bundle.c
+++ b/bundle.c
@@ -409,7 +409,7 @@
 int create_bundle(struct bundle_header *header, const char *path,
 		  int argc, const char **argv)
 {
-	static struct lock_file lock;
+	struct lock_file lock = LOCK_INIT;
 	int bundle_fd = -1;
 	int bundle_to_stdout;
 	int ref_count = 0;
diff --git a/cache-tree.c b/cache-tree.c
index 6a555f4..2566382 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -385,7 +385,7 @@
 		/*
 		 * "sub" can be an empty tree if all subentries are i-t-a.
 		 */
-		if (contains_ita && !oidcmp(oid, &empty_tree_oid))
+		if (contains_ita && is_empty_tree_oid(oid))
 			continue;
 
 		strbuf_grow(&buffer, entlen + 100);
@@ -523,7 +523,7 @@
 	if (0 <= it->entry_count) {
 		if (size < rawsz)
 			goto free_return;
-		memcpy(it->oid.hash, (const unsigned char*)buf, rawsz);
+		oidread(&it->oid, (const unsigned char *)buf);
 		buf += rawsz;
 		size -= rawsz;
 	}
diff --git a/cache.h b/cache.h
index 77b7ace..89a107a 100644
--- a/cache.h
+++ b/cache.h
@@ -324,7 +324,7 @@
 		 drop_cache_tree : 1;
 	struct hashmap name_hash;
 	struct hashmap dir_hash;
-	unsigned char sha1[20];
+	struct object_id oid;
 	struct untracked_cache *untracked;
 	uint64_t fsmonitor_last_update;
 	struct ewah_bitmap *fsmonitor_dirty;
@@ -373,6 +373,13 @@
 #define read_blob_data_from_cache(path, sz) read_blob_data_from_index(&the_index, (path), (sz))
 #endif
 
+#define TYPE_BITS 3
+
+/*
+ * Values in this enum (except those outside the 3 bit range) are part
+ * of pack file format. See Documentation/technical/pack-format.txt
+ * for more information.
+ */
 enum object_type {
 	OBJ_BAD = -1,
 	OBJ_NONE = 0,
@@ -428,6 +435,7 @@
 #define GIT_ICASE_PATHSPECS_ENVIRONMENT "GIT_ICASE_PATHSPECS"
 #define GIT_QUARANTINE_ENVIRONMENT "GIT_QUARANTINE_PATH"
 #define GIT_OPTIONAL_LOCKS_ENVIRONMENT "GIT_OPTIONAL_LOCKS"
+#define GIT_TEXT_DOMAIN_DIR_ENVIRONMENT "GIT_TEXTDOMAINDIR"
 
 /*
  * Environment variable used in handshaking the wire protocol.
@@ -634,7 +642,7 @@
  */
 extern int index_has_changes(struct strbuf *sb);
 
-extern int verify_path(const char *path);
+extern int verify_path(const char *path, unsigned mode);
 extern int strcmp_offset(const char *s1, const char *s2, size_t *first_change);
 extern int index_dir_exists(struct index_state *istate, const char *name, int namelen);
 extern void adjust_dirname_case(struct index_state *istate, char *name);
@@ -805,6 +813,7 @@
 
 extern int fsync_object_files;
 extern int core_preload_index;
+extern int core_commit_graph;
 extern int core_apply_sparse_checkout;
 extern int precomposed_unicode;
 extern int protect_hfs;
@@ -1008,21 +1017,10 @@
 	memset(oid->hash, 0, GIT_MAX_RAWSZ);
 }
 
-
-#define EMPTY_TREE_SHA1_HEX \
-	"4b825dc642cb6eb9a060e54bf8d69288fbee4904"
-#define EMPTY_TREE_SHA1_BIN_LITERAL \
-	 "\x4b\x82\x5d\xc6\x42\xcb\x6e\xb9\xa0\x60" \
-	 "\xe5\x4b\xf8\xd6\x92\x88\xfb\xee\x49\x04"
-extern const struct object_id empty_tree_oid;
-#define EMPTY_TREE_SHA1_BIN (empty_tree_oid.hash)
-
-#define EMPTY_BLOB_SHA1_HEX \
-	"e69de29bb2d1d6434b8b29ae775ad8c2e48c5391"
-#define EMPTY_BLOB_SHA1_BIN_LITERAL \
-	"\xe6\x9d\xe2\x9b\xb2\xd1\xd6\x43\x4b\x8b" \
-	"\x29\xae\x77\x5a\xd8\xc2\xe4\x8c\x53\x91"
-extern const struct object_id empty_blob_oid;
+static inline void oidread(struct object_id *oid, const unsigned char *hash)
+{
+	memcpy(oid->hash, hash, the_hash_algo->rawsz);
+}
 
 static inline int is_empty_blob_sha1(const unsigned char *sha1)
 {
@@ -1044,6 +1042,9 @@
 	return !oidcmp(oid, the_hash_algo->empty_tree);
 }
 
+const char *empty_tree_oid_hex(void);
+const char *empty_blob_oid_hex(void);
+
 /* set default permissions by passing mode arguments to open(2) */
 int git_mkstemps_mode(char *pattern, int suffix_len, int mode);
 int git_mkstemp_mode(char *pattern, int mode);
@@ -1159,7 +1160,15 @@
 int longest_ancestor_length(const char *path, struct string_list *prefixes);
 char *strip_path_suffix(const char *path, const char *suffix);
 int daemon_avoid_alias(const char *path);
-extern int is_ntfs_dotgit(const char *name);
+
+/*
+ * These functions match their is_hfs_dotgit() counterparts; see utf8.h for
+ * details.
+ */
+int is_ntfs_dotgit(const char *name);
+int is_ntfs_dotgitmodules(const char *name);
+int is_ntfs_dotgitignore(const char *name);
+int is_ntfs_dotgitattributes(const char *name);
 
 /*
  * Returns true iff "str" could be confused as a command-line option when
@@ -1191,27 +1200,8 @@
 	return read_object_file_extended(oid, type, size, 1);
 }
 
-/*
- * This internal function is only declared here for the benefit of
- * lookup_replace_object().  Please do not call it directly.
- */
-extern const struct object_id *do_lookup_replace_object(const struct object_id *oid);
-
-/*
- * If object sha1 should be replaced, return the replacement object's
- * name (replaced recursively, if necessary).  The return value is
- * either sha1 or a pointer to a permanently-allocated value.  When
- * object replacement is suppressed, always return sha1.
- */
-static inline const struct object_id *lookup_replace_object(const struct object_id *oid)
-{
-	if (!check_replace_refs)
-		return oid;
-	return do_lookup_replace_object(oid);
-}
-
 /* Read and unpack an object file into memory, write memory to an object file */
-extern int oid_object_info(const struct object_id *, unsigned long *);
+int oid_object_info(struct repository *r, const struct object_id *, unsigned long *);
 
 extern int hash_object_file(const void *buf, unsigned long len,
 			    const char *type, struct object_id *oid);
@@ -1270,7 +1260,7 @@
  * with the specified name.  This function does not respect replace
  * references.
  */
-extern int has_loose_object_nonlocal(const unsigned char *sha1);
+extern int has_loose_object_nonlocal(const struct object_id *oid);
 
 extern void assert_oid_type(const struct object_id *oid, enum object_type expect);
 
@@ -1301,7 +1291,6 @@
 #define FALLBACK_DEFAULT_ABBREV 7
 
 struct object_context {
-	unsigned char tree[20];
 	unsigned mode;
 	/*
 	 * symlink_path is only used by get_tree_entry_follow_symlinks,
@@ -1568,7 +1557,6 @@
 
 struct pack_entry {
 	off_t offset;
-	unsigned char sha1[20];
 	struct packed_git *p;
 };
 
@@ -1692,7 +1680,10 @@
 #define OBJECT_INFO_QUICK 8
 /* Do not check loose object */
 #define OBJECT_INFO_IGNORE_LOOSE 16
-extern int oid_object_info_extended(const struct object_id *, struct object_info *, unsigned flags);
+
+int oid_object_info_extended(struct repository *r,
+			     const struct object_id *,
+			     struct object_info *, unsigned flags);
 
 /*
  * Set this to 0 to prevent sha1_object_info_extended() from fetching missing
@@ -1835,11 +1826,6 @@
 void overlay_tree_on_index(struct index_state *istate,
 			   const char *tree_name, const char *prefix);
 
-char *alias_lookup(const char *alias);
-int split_cmdline(char *cmdline, const char ***argv);
-/* Takes a negative value returned by split_cmdline */
-const char *split_cmdline_strerror(int cmdline_errno);
-
 /* setup.c */
 struct startup_info {
 	int have_repository;
diff --git a/checkout.c b/checkout.c
index ac42630..bdefc88 100644
--- a/checkout.c
+++ b/checkout.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "remote.h"
+#include "refspec.h"
 #include "checkout.h"
 
 struct tracking_name_data {
@@ -12,8 +13,8 @@
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
 	struct tracking_name_data *cb = cb_data;
-	struct refspec query;
-	memset(&query, 0, sizeof(struct refspec));
+	struct refspec_item query;
+	memset(&query, 0, sizeof(struct refspec_item));
 	query.src = cb->src_ref;
 	if (remote_find_tracking(remote, &query) ||
 	    get_oid(query.dst, cb->dst_oid)) {
diff --git a/ci/lib-travisci.sh b/ci/lib-travisci.sh
index 109ef28..ceecc88 100755
--- a/ci/lib-travisci.sh
+++ b/ci/lib-travisci.sh
@@ -99,6 +99,9 @@
 export GIT_PROVE_OPTS="--timer --jobs 3 --state=failed,slow,save"
 export GIT_TEST_OPTS="--verbose-log -x"
 export GIT_TEST_CLONE_2GB=YesPlease
+if [ "$jobname" = linux-gcc ]; then
+	export CC=gcc-8
+fi
 
 case "$jobname" in
 linux-clang|linux-gcc)
diff --git a/ci/run-build-and-tests.sh b/ci/run-build-and-tests.sh
index 3735ce4..4b04c75 100755
--- a/ci/run-build-and-tests.sh
+++ b/ci/run-build-and-tests.sh
@@ -11,7 +11,10 @@
 make --quiet test
 if test "$jobname" = "linux-gcc"
 then
-	GIT_TEST_SPLIT_INDEX=YesPlease make --quiet test
+	export GIT_TEST_SPLIT_INDEX=yes
+	export GIT_TEST_FULL_IN_PACK_ARRAY=true
+	export GIT_TEST_OE_SIZE=10
+	make --quiet test
 fi
 
 check_unignored_build_artifacts
diff --git a/color.c b/color.c
index f277e72..b1c24c6 100644
--- a/color.c
+++ b/color.c
@@ -174,7 +174,7 @@
 		break;
 	case COLOR_ANSI:
 		if (len < 2)
-			die("BUG: color parsing ran out of space");
+			BUG("color parsing ran out of space");
 		*out++ = type;
 		*out++ = '0' + c->value;
 		break;
@@ -256,7 +256,7 @@
 #undef OUT
 #define OUT(x) do { \
 	if (dst == end) \
-		die("BUG: color parsing ran out of space"); \
+		BUG("color parsing ran out of space"); \
 	*dst++ = (x); \
 } while(0)
 
@@ -319,18 +319,20 @@
 	return GIT_COLOR_AUTO;
 }
 
-static int check_auto_color(void)
+static int check_auto_color(int fd)
 {
-	if (color_stdout_is_tty < 0)
-		color_stdout_is_tty = isatty(1);
-	if (color_stdout_is_tty || (pager_in_use() && pager_use_color)) {
+	static int color_stderr_is_tty = -1;
+	int *is_tty_p = fd == 1 ? &color_stdout_is_tty : &color_stderr_is_tty;
+	if (*is_tty_p < 0)
+		*is_tty_p = isatty(fd);
+	if (*is_tty_p || (fd == 1 && pager_in_use() && pager_use_color)) {
 		if (!is_terminal_dumb())
 			return 1;
 	}
 	return 0;
 }
 
-int want_color(int var)
+int want_color_fd(int fd, int var)
 {
 	/*
 	 * NEEDSWORK: This function is sometimes used from multiple threads, and
@@ -339,15 +341,15 @@
 	 * is listed in .tsan-suppressions for the time being.
 	 */
 
-	static int want_auto = -1;
+	static int want_auto[3] = { -1, -1, -1 };
 
 	if (var < 0)
 		var = git_use_color_default;
 
 	if (var == GIT_COLOR_AUTO) {
-		if (want_auto < 0)
-			want_auto = check_auto_color();
-		return want_auto;
+		if (want_auto[fd] < 0)
+			want_auto[fd] = check_auto_color(fd);
+		return want_auto[fd];
 	}
 	return var;
 }
diff --git a/color.h b/color.h
index cd0bced..5b744e1 100644
--- a/color.h
+++ b/color.h
@@ -88,7 +88,9 @@
  * Return a boolean whether to use color, where the argument 'var' is
  * one of GIT_COLOR_UNKNOWN, GIT_COLOR_NEVER, GIT_COLOR_ALWAYS, GIT_COLOR_AUTO.
  */
-int want_color(int var);
+int want_color_fd(int fd, int var);
+#define want_color(colorbool) want_color_fd(1, (colorbool))
+#define want_color_stderr(colorbool) want_color_fd(2, (colorbool))
 
 /*
  * Translate a Git color from 'value' into a string that the terminal can
diff --git a/column.c b/column.c
index 49ab85b..2165297 100644
--- a/column.c
+++ b/column.c
@@ -214,7 +214,7 @@
 		display_table(list, colopts, &nopts);
 		break;
 	default:
-		die("BUG: invalid layout mode %d", COL_LAYOUT(colopts));
+		BUG("invalid layout mode %d", COL_LAYOUT(colopts));
 	}
 }
 
diff --git a/command-list.txt b/command-list.txt
index a1fad28..e1c26c1 100644
--- a/command-list.txt
+++ b/command-list.txt
@@ -1,23 +1,58 @@
-# common commands are grouped by themes
-# these groups are output by 'git help' in the order declared here.
-# map each common command in the command list to one of these groups.
-### common groups (do not change this line)
-init         start a working area (see also: git help tutorial)
-worktree     work on the current change (see also: git help everyday)
-info         examine the history and state (see also: git help revisions)
-history      grow, mark and tweak your common history
-remote       collaborate (see also: git help workflows)
-
-### command list (do not change this line)
-# command name                          category [deprecated] [common]
+# Command classification list
+# ---------------------------
+# All supported commands, builtin or external, must be described in
+# here. This info is used to list commands in various places. Each
+# command is on one line followed by one or more attributes.
+#
+# The first attribute group is mandatory and indicates the command
+# type. This group includes:
+#
+#   mainporcelain
+#   ancillarymanipulators
+#   ancillaryinterrogators
+#   foreignscminterface
+#   plumbingmanipulators
+#   plumbinginterrogators
+#   synchingrepositories
+#   synchelpers
+#   purehelpers
+#
+# The type names are self explanatory. But if you want to see what
+# command belongs to what group to get a better picture, have a look
+# at "git" man page, "GIT COMMANDS" section.
+#
+# Commands of type mainporcelain can also optionally have one of these
+# attributes:
+#
+#   init
+#   worktree
+#   info
+#   history
+#   remote
+#
+# These commands are considered "common" and will show up in "git
+# help" output in groups. Uncommon porcelain commands must not
+# specify any of these attributes.
+#
+# "complete" attribute is used to mark that the command should be
+# completable by git-completion.bash. Note that by default,
+# mainporcelain commands are completable so you don't need this
+# attribute.
+#
+# As part of the Git man page list, the man(5/7) guides are also
+# specified here, which can only have "guide" attribute and nothing
+# else.
+#
+### command list (do not change this line, also do not change alignment)
+# command name                          category [category] [category]
 git-add                                 mainporcelain           worktree
 git-am                                  mainporcelain
 git-annotate                            ancillaryinterrogators
-git-apply                               plumbingmanipulators
+git-apply                               plumbingmanipulators            complete
 git-archimport                          foreignscminterface
 git-archive                             mainporcelain
 git-bisect                              mainporcelain           info
-git-blame                               ancillaryinterrogators
+git-blame                               ancillaryinterrogators          complete
 git-branch                              mainporcelain           history
 git-bundle                              mainporcelain
 git-cat-file                            plumbinginterrogators
@@ -27,15 +62,16 @@
 git-checkout                            mainporcelain           history
 git-checkout-index                      plumbingmanipulators
 git-check-ref-format                    purehelpers
-git-cherry                              ancillaryinterrogators
+git-cherry                              ancillaryinterrogators          complete
 git-cherry-pick                         mainporcelain
 git-citool                              mainporcelain
 git-clean                               mainporcelain
 git-clone                               mainporcelain           init
 git-column                              purehelpers
 git-commit                              mainporcelain           history
+git-commit-graph                        plumbingmanipulators
 git-commit-tree                         plumbingmanipulators
-git-config                              ancillarymanipulators
+git-config                              ancillarymanipulators           complete
 git-count-objects                       ancillaryinterrogators
 git-credential                          purehelpers
 git-credential-cache                    purehelpers
@@ -49,7 +85,7 @@
 git-diff-files                          plumbinginterrogators
 git-diff-index                          plumbinginterrogators
 git-diff-tree                           plumbinginterrogators
-git-difftool                            ancillaryinterrogators
+git-difftool                            ancillaryinterrogators          complete
 git-fast-export                         ancillarymanipulators
 git-fast-import                         ancillarymanipulators
 git-fetch                               mainporcelain           remote
@@ -58,20 +94,20 @@
 git-fmt-merge-msg                       purehelpers
 git-for-each-ref                        plumbinginterrogators
 git-format-patch                        mainporcelain
-git-fsck                                ancillaryinterrogators
+git-fsck                                ancillaryinterrogators          complete
 git-gc                                  mainporcelain
 git-get-tar-commit-id                   ancillaryinterrogators
 git-grep                                mainporcelain           info
 git-gui                                 mainporcelain
 git-hash-object                         plumbingmanipulators
-git-help                                ancillaryinterrogators
+git-help                                ancillaryinterrogators          complete
 git-http-backend                        synchingrepositories
 git-http-fetch                          synchelpers
 git-http-push                           synchelpers
 git-imap-send                           foreignscminterface
 git-index-pack                          plumbingmanipulators
 git-init                                mainporcelain           init
-git-instaweb                            ancillaryinterrogators
+git-instaweb                            ancillaryinterrogators          complete
 git-interpret-trailers                  purehelpers
 gitk                                    mainporcelain
 git-log                                 mainporcelain           info
@@ -85,7 +121,7 @@
 git-merge-file                          plumbingmanipulators
 git-merge-index                         plumbingmanipulators
 git-merge-one-file                      purehelpers
-git-mergetool                           ancillarymanipulators
+git-mergetool                           ancillarymanipulators           complete
 git-merge-tree                          ancillaryinterrogators
 git-mktag                               plumbingmanipulators
 git-mktree                              plumbingmanipulators
@@ -106,28 +142,29 @@
 git-read-tree                           plumbingmanipulators
 git-rebase                              mainporcelain           history
 git-receive-pack                        synchelpers
-git-reflog                              ancillarymanipulators
-git-remote                              ancillarymanipulators
-git-repack                              ancillarymanipulators
-git-replace                             ancillarymanipulators
-git-request-pull                        foreignscminterface
+git-reflog                              ancillarymanipulators           complete
+git-remote                              ancillarymanipulators           complete
+git-repack                              ancillarymanipulators           complete
+git-replace                             ancillarymanipulators           complete
+git-request-pull                        foreignscminterface             complete
 git-rerere                              ancillaryinterrogators
 git-reset                               mainporcelain           worktree
 git-revert                              mainporcelain
 git-rev-list                            plumbinginterrogators
 git-rev-parse                           ancillaryinterrogators
 git-rm                                  mainporcelain           worktree
-git-send-email                          foreignscminterface
+git-send-email                          foreignscminterface             complete
 git-send-pack                           synchingrepositories
 git-shell                               synchelpers
 git-shortlog                            mainporcelain
 git-show                                mainporcelain           info
-git-show-branch                         ancillaryinterrogators
+git-show-branch                         ancillaryinterrogators          complete
 git-show-index                          plumbinginterrogators
 git-show-ref                            plumbinginterrogators
 git-sh-i18n                             purehelpers
 git-sh-setup                            purehelpers
 git-stash                               mainporcelain
+git-stage                                                               complete
 git-status                              mainporcelain           info
 git-stripspace                          purehelpers
 git-submodule                           mainporcelain
@@ -146,6 +183,22 @@
 git-verify-pack                         plumbinginterrogators
 git-verify-tag                          ancillaryinterrogators
 gitweb                                  ancillaryinterrogators
-git-whatchanged                         ancillaryinterrogators
+git-whatchanged                         ancillaryinterrogators          complete
 git-worktree                            mainporcelain
 git-write-tree                          plumbingmanipulators
+gitattributes                           guide
+gitcli                                  guide
+gitcore-tutorial                        guide
+gitcvs-migration                        guide
+gitdiffcore                             guide
+giteveryday                             guide
+gitglossary                             guide
+githooks                                guide
+gitignore                               guide
+gitmodules                              guide
+gitnamespaces                           guide
+gitrepository-layout                    guide
+gitrevisions                            guide
+gittutorial-2                           guide
+gittutorial                             guide
+gitworkflows                            guide
diff --git a/commit-graph.c b/commit-graph.c
new file mode 100644
index 0000000..4c61270
--- /dev/null
+++ b/commit-graph.c
@@ -0,0 +1,761 @@
+#include "cache.h"
+#include "config.h"
+#include "git-compat-util.h"
+#include "lockfile.h"
+#include "pack.h"
+#include "packfile.h"
+#include "commit.h"
+#include "object.h"
+#include "revision.h"
+#include "sha1-lookup.h"
+#include "commit-graph.h"
+#include "object-store.h"
+
+#define GRAPH_SIGNATURE 0x43475048 /* "CGPH" */
+#define GRAPH_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
+#define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
+#define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */
+#define GRAPH_CHUNKID_LARGEEDGES 0x45444745 /* "EDGE" */
+
+#define GRAPH_DATA_WIDTH 36
+
+#define GRAPH_VERSION_1 0x1
+#define GRAPH_VERSION GRAPH_VERSION_1
+
+#define GRAPH_OID_VERSION_SHA1 1
+#define GRAPH_OID_LEN_SHA1 GIT_SHA1_RAWSZ
+#define GRAPH_OID_VERSION GRAPH_OID_VERSION_SHA1
+#define GRAPH_OID_LEN GRAPH_OID_LEN_SHA1
+
+#define GRAPH_OCTOPUS_EDGES_NEEDED 0x80000000
+#define GRAPH_PARENT_MISSING 0x7fffffff
+#define GRAPH_EDGE_LAST_MASK 0x7fffffff
+#define GRAPH_PARENT_NONE 0x70000000
+
+#define GRAPH_LAST_EDGE 0x80000000
+
+#define GRAPH_FANOUT_SIZE (4 * 256)
+#define GRAPH_CHUNKLOOKUP_WIDTH 12
+#define GRAPH_MIN_SIZE (5 * GRAPH_CHUNKLOOKUP_WIDTH + GRAPH_FANOUT_SIZE + \
+			GRAPH_OID_LEN + 8)
+
+char *get_commit_graph_filename(const char *obj_dir)
+{
+	return xstrfmt("%s/info/commit-graph", obj_dir);
+}
+
+static struct commit_graph *alloc_commit_graph(void)
+{
+	struct commit_graph *g = xcalloc(1, sizeof(*g));
+	g->graph_fd = -1;
+
+	return g;
+}
+
+struct commit_graph *load_commit_graph_one(const char *graph_file)
+{
+	void *graph_map;
+	const unsigned char *data, *chunk_lookup;
+	size_t graph_size;
+	struct stat st;
+	uint32_t i;
+	struct commit_graph *graph;
+	int fd = git_open(graph_file);
+	uint64_t last_chunk_offset;
+	uint32_t last_chunk_id;
+	uint32_t graph_signature;
+	unsigned char graph_version, hash_version;
+
+	if (fd < 0)
+		return NULL;
+	if (fstat(fd, &st)) {
+		close(fd);
+		return NULL;
+	}
+	graph_size = xsize_t(st.st_size);
+
+	if (graph_size < GRAPH_MIN_SIZE) {
+		close(fd);
+		die("graph file %s is too small", graph_file);
+	}
+	graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
+	data = (const unsigned char *)graph_map;
+
+	graph_signature = get_be32(data);
+	if (graph_signature != GRAPH_SIGNATURE) {
+		error("graph signature %X does not match signature %X",
+		      graph_signature, GRAPH_SIGNATURE);
+		goto cleanup_fail;
+	}
+
+	graph_version = *(unsigned char*)(data + 4);
+	if (graph_version != GRAPH_VERSION) {
+		error("graph version %X does not match version %X",
+		      graph_version, GRAPH_VERSION);
+		goto cleanup_fail;
+	}
+
+	hash_version = *(unsigned char*)(data + 5);
+	if (hash_version != GRAPH_OID_VERSION) {
+		error("hash version %X does not match version %X",
+		      hash_version, GRAPH_OID_VERSION);
+		goto cleanup_fail;
+	}
+
+	graph = alloc_commit_graph();
+
+	graph->hash_len = GRAPH_OID_LEN;
+	graph->num_chunks = *(unsigned char*)(data + 6);
+	graph->graph_fd = fd;
+	graph->data = graph_map;
+	graph->data_len = graph_size;
+
+	last_chunk_id = 0;
+	last_chunk_offset = 8;
+	chunk_lookup = data + 8;
+	for (i = 0; i < graph->num_chunks; i++) {
+		uint32_t chunk_id = get_be32(chunk_lookup + 0);
+		uint64_t chunk_offset = get_be64(chunk_lookup + 4);
+		int chunk_repeated = 0;
+
+		chunk_lookup += GRAPH_CHUNKLOOKUP_WIDTH;
+
+		if (chunk_offset > graph_size - GIT_MAX_RAWSZ) {
+			error("improper chunk offset %08x%08x", (uint32_t)(chunk_offset >> 32),
+			      (uint32_t)chunk_offset);
+			goto cleanup_fail;
+		}
+
+		switch (chunk_id) {
+		case GRAPH_CHUNKID_OIDFANOUT:
+			if (graph->chunk_oid_fanout)
+				chunk_repeated = 1;
+			else
+				graph->chunk_oid_fanout = (uint32_t*)(data + chunk_offset);
+			break;
+
+		case GRAPH_CHUNKID_OIDLOOKUP:
+			if (graph->chunk_oid_lookup)
+				chunk_repeated = 1;
+			else
+				graph->chunk_oid_lookup = data + chunk_offset;
+			break;
+
+		case GRAPH_CHUNKID_DATA:
+			if (graph->chunk_commit_data)
+				chunk_repeated = 1;
+			else
+				graph->chunk_commit_data = data + chunk_offset;
+			break;
+
+		case GRAPH_CHUNKID_LARGEEDGES:
+			if (graph->chunk_large_edges)
+				chunk_repeated = 1;
+			else
+				graph->chunk_large_edges = data + chunk_offset;
+			break;
+		}
+
+		if (chunk_repeated) {
+			error("chunk id %08x appears multiple times", chunk_id);
+			goto cleanup_fail;
+		}
+
+		if (last_chunk_id == GRAPH_CHUNKID_OIDLOOKUP)
+		{
+			graph->num_commits = (chunk_offset - last_chunk_offset)
+					     / graph->hash_len;
+		}
+
+		last_chunk_id = chunk_id;
+		last_chunk_offset = chunk_offset;
+	}
+
+	return graph;
+
+cleanup_fail:
+	munmap(graph_map, graph_size);
+	close(fd);
+	exit(1);
+}
+
+/* global storage */
+static struct commit_graph *commit_graph = NULL;
+
+static void prepare_commit_graph_one(const char *obj_dir)
+{
+	char *graph_name;
+
+	if (commit_graph)
+		return;
+
+	graph_name = get_commit_graph_filename(obj_dir);
+	commit_graph = load_commit_graph_one(graph_name);
+
+	FREE_AND_NULL(graph_name);
+}
+
+static int prepare_commit_graph_run_once = 0;
+static void prepare_commit_graph(void)
+{
+	struct alternate_object_database *alt;
+	char *obj_dir;
+
+	if (prepare_commit_graph_run_once)
+		return;
+	prepare_commit_graph_run_once = 1;
+
+	obj_dir = get_object_directory();
+	prepare_commit_graph_one(obj_dir);
+	prepare_alt_odb(the_repository);
+	for (alt = the_repository->objects->alt_odb_list;
+	     !commit_graph && alt;
+	     alt = alt->next)
+		prepare_commit_graph_one(alt->path);
+}
+
+static void close_commit_graph(void)
+{
+	if (!commit_graph)
+		return;
+
+	if (commit_graph->graph_fd >= 0) {
+		munmap((void *)commit_graph->data, commit_graph->data_len);
+		commit_graph->data = NULL;
+		close(commit_graph->graph_fd);
+	}
+
+	FREE_AND_NULL(commit_graph);
+}
+
+static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
+{
+	return bsearch_hash(oid->hash, g->chunk_oid_fanout,
+			    g->chunk_oid_lookup, g->hash_len, pos);
+}
+
+static struct commit_list **insert_parent_or_die(struct commit_graph *g,
+						 uint64_t pos,
+						 struct commit_list **pptr)
+{
+	struct commit *c;
+	struct object_id oid;
+	hashcpy(oid.hash, g->chunk_oid_lookup + g->hash_len * pos);
+	c = lookup_commit(&oid);
+	if (!c)
+		die("could not find commit %s", oid_to_hex(&oid));
+	c->graph_pos = pos;
+	return &commit_list_insert(c, pptr)->next;
+}
+
+static int fill_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t pos)
+{
+	uint32_t edge_value;
+	uint32_t *parent_data_ptr;
+	uint64_t date_low, date_high;
+	struct commit_list **pptr;
+	const unsigned char *commit_data = g->chunk_commit_data + (g->hash_len + 16) * pos;
+
+	item->object.parsed = 1;
+	item->graph_pos = pos;
+
+	item->maybe_tree = NULL;
+
+	date_high = get_be32(commit_data + g->hash_len + 8) & 0x3;
+	date_low = get_be32(commit_data + g->hash_len + 12);
+	item->date = (timestamp_t)((date_high << 32) | date_low);
+
+	pptr = &item->parents;
+
+	edge_value = get_be32(commit_data + g->hash_len);
+	if (edge_value == GRAPH_PARENT_NONE)
+		return 1;
+	pptr = insert_parent_or_die(g, edge_value, pptr);
+
+	edge_value = get_be32(commit_data + g->hash_len + 4);
+	if (edge_value == GRAPH_PARENT_NONE)
+		return 1;
+	if (!(edge_value & GRAPH_OCTOPUS_EDGES_NEEDED)) {
+		pptr = insert_parent_or_die(g, edge_value, pptr);
+		return 1;
+	}
+
+	parent_data_ptr = (uint32_t*)(g->chunk_large_edges +
+			  4 * (uint64_t)(edge_value & GRAPH_EDGE_LAST_MASK));
+	do {
+		edge_value = get_be32(parent_data_ptr);
+		pptr = insert_parent_or_die(g,
+					    edge_value & GRAPH_EDGE_LAST_MASK,
+					    pptr);
+		parent_data_ptr++;
+	} while (!(edge_value & GRAPH_LAST_EDGE));
+
+	return 1;
+}
+
+int parse_commit_in_graph(struct commit *item)
+{
+	if (!core_commit_graph)
+		return 0;
+	if (item->object.parsed)
+		return 1;
+
+	prepare_commit_graph();
+	if (commit_graph) {
+		uint32_t pos;
+		int found;
+		if (item->graph_pos != COMMIT_NOT_FROM_GRAPH) {
+			pos = item->graph_pos;
+			found = 1;
+		} else {
+			found = bsearch_graph(commit_graph, &(item->object.oid), &pos);
+		}
+
+		if (found)
+			return fill_commit_in_graph(item, commit_graph, pos);
+	}
+
+	return 0;
+}
+
+static struct tree *load_tree_for_commit(struct commit_graph *g, struct commit *c)
+{
+	struct object_id oid;
+	const unsigned char *commit_data = g->chunk_commit_data +
+					   GRAPH_DATA_WIDTH * (c->graph_pos);
+
+	hashcpy(oid.hash, commit_data);
+	c->maybe_tree = lookup_tree(&oid);
+
+	return c->maybe_tree;
+}
+
+struct tree *get_commit_tree_in_graph(const struct commit *c)
+{
+	if (c->maybe_tree)
+		return c->maybe_tree;
+	if (c->graph_pos == COMMIT_NOT_FROM_GRAPH)
+		BUG("get_commit_tree_in_graph called from non-commit-graph commit");
+
+	return load_tree_for_commit(commit_graph, (struct commit *)c);
+}
+
+static void write_graph_chunk_fanout(struct hashfile *f,
+				     struct commit **commits,
+				     int nr_commits)
+{
+	int i, count = 0;
+	struct commit **list = commits;
+
+	/*
+	 * Write the first-level table (the list is sorted,
+	 * but we use a 256-entry lookup to be able to avoid
+	 * having to do eight extra binary search iterations).
+	 */
+	for (i = 0; i < 256; i++) {
+		while (count < nr_commits) {
+			if ((*list)->object.oid.hash[0] != i)
+				break;
+			count++;
+			list++;
+		}
+
+		hashwrite_be32(f, count);
+	}
+}
+
+static void write_graph_chunk_oids(struct hashfile *f, int hash_len,
+				   struct commit **commits, int nr_commits)
+{
+	struct commit **list = commits;
+	int count;
+	for (count = 0; count < nr_commits; count++, list++)
+		hashwrite(f, (*list)->object.oid.hash, (int)hash_len);
+}
+
+static const unsigned char *commit_to_sha1(size_t index, void *table)
+{
+	struct commit **commits = table;
+	return commits[index]->object.oid.hash;
+}
+
+static void write_graph_chunk_data(struct hashfile *f, int hash_len,
+				   struct commit **commits, int nr_commits)
+{
+	struct commit **list = commits;
+	struct commit **last = commits + nr_commits;
+	uint32_t num_extra_edges = 0;
+
+	while (list < last) {
+		struct commit_list *parent;
+		int edge_value;
+		uint32_t packedDate[2];
+
+		parse_commit(*list);
+		hashwrite(f, get_commit_tree_oid(*list)->hash, hash_len);
+
+		parent = (*list)->parents;
+
+		if (!parent)
+			edge_value = GRAPH_PARENT_NONE;
+		else {
+			edge_value = sha1_pos(parent->item->object.oid.hash,
+					      commits,
+					      nr_commits,
+					      commit_to_sha1);
+
+			if (edge_value < 0)
+				edge_value = GRAPH_PARENT_MISSING;
+		}
+
+		hashwrite_be32(f, edge_value);
+
+		if (parent)
+			parent = parent->next;
+
+		if (!parent)
+			edge_value = GRAPH_PARENT_NONE;
+		else if (parent->next)
+			edge_value = GRAPH_OCTOPUS_EDGES_NEEDED | num_extra_edges;
+		else {
+			edge_value = sha1_pos(parent->item->object.oid.hash,
+					      commits,
+					      nr_commits,
+					      commit_to_sha1);
+			if (edge_value < 0)
+				edge_value = GRAPH_PARENT_MISSING;
+		}
+
+		hashwrite_be32(f, edge_value);
+
+		if (edge_value & GRAPH_OCTOPUS_EDGES_NEEDED) {
+			do {
+				num_extra_edges++;
+				parent = parent->next;
+			} while (parent);
+		}
+
+		if (sizeof((*list)->date) > 4)
+			packedDate[0] = htonl(((*list)->date >> 32) & 0x3);
+		else
+			packedDate[0] = 0;
+
+		packedDate[1] = htonl((*list)->date);
+		hashwrite(f, packedDate, 8);
+
+		list++;
+	}
+}
+
+static void write_graph_chunk_large_edges(struct hashfile *f,
+					  struct commit **commits,
+					  int nr_commits)
+{
+	struct commit **list = commits;
+	struct commit **last = commits + nr_commits;
+	struct commit_list *parent;
+
+	while (list < last) {
+		int num_parents = 0;
+		for (parent = (*list)->parents; num_parents < 3 && parent;
+		     parent = parent->next)
+			num_parents++;
+
+		if (num_parents <= 2) {
+			list++;
+			continue;
+		}
+
+		/* Since num_parents > 2, this initializer is safe. */
+		for (parent = (*list)->parents->next; parent; parent = parent->next) {
+			int edge_value = sha1_pos(parent->item->object.oid.hash,
+						  commits,
+						  nr_commits,
+						  commit_to_sha1);
+
+			if (edge_value < 0)
+				edge_value = GRAPH_PARENT_MISSING;
+			else if (!parent->next)
+				edge_value |= GRAPH_LAST_EDGE;
+
+			hashwrite_be32(f, edge_value);
+		}
+
+		list++;
+	}
+}
+
+static int commit_compare(const void *_a, const void *_b)
+{
+	const struct object_id *a = (const struct object_id *)_a;
+	const struct object_id *b = (const struct object_id *)_b;
+	return oidcmp(a, b);
+}
+
+struct packed_commit_list {
+	struct commit **list;
+	int nr;
+	int alloc;
+};
+
+struct packed_oid_list {
+	struct object_id *list;
+	int nr;
+	int alloc;
+};
+
+static int add_packed_commits(const struct object_id *oid,
+			      struct packed_git *pack,
+			      uint32_t pos,
+			      void *data)
+{
+	struct packed_oid_list *list = (struct packed_oid_list*)data;
+	enum object_type type;
+	off_t offset = nth_packed_object_offset(pack, pos);
+	struct object_info oi = OBJECT_INFO_INIT;
+
+	oi.typep = &type;
+	if (packed_object_info(the_repository, pack, offset, &oi) < 0)
+		die("unable to get type of object %s", oid_to_hex(oid));
+
+	if (type != OBJ_COMMIT)
+		return 0;
+
+	ALLOC_GROW(list->list, list->nr + 1, list->alloc);
+	oidcpy(&(list->list[list->nr]), oid);
+	list->nr++;
+
+	return 0;
+}
+
+static void add_missing_parents(struct packed_oid_list *oids, struct commit *commit)
+{
+	struct commit_list *parent;
+	for (parent = commit->parents; parent; parent = parent->next) {
+		if (!(parent->item->object.flags & UNINTERESTING)) {
+			ALLOC_GROW(oids->list, oids->nr + 1, oids->alloc);
+			oidcpy(&oids->list[oids->nr], &(parent->item->object.oid));
+			oids->nr++;
+			parent->item->object.flags |= UNINTERESTING;
+		}
+	}
+}
+
+static void close_reachable(struct packed_oid_list *oids)
+{
+	int i;
+	struct commit *commit;
+
+	for (i = 0; i < oids->nr; i++) {
+		commit = lookup_commit(&oids->list[i]);
+		if (commit)
+			commit->object.flags |= UNINTERESTING;
+	}
+
+	/*
+	 * As this loop runs, oids->nr may grow, but not more
+	 * than the number of missing commits in the reachable
+	 * closure.
+	 */
+	for (i = 0; i < oids->nr; i++) {
+		commit = lookup_commit(&oids->list[i]);
+
+		if (commit && !parse_commit(commit))
+			add_missing_parents(oids, commit);
+	}
+
+	for (i = 0; i < oids->nr; i++) {
+		commit = lookup_commit(&oids->list[i]);
+
+		if (commit)
+			commit->object.flags &= ~UNINTERESTING;
+	}
+}
+
+void write_commit_graph(const char *obj_dir,
+			const char **pack_indexes,
+			int nr_packs,
+			const char **commit_hex,
+			int nr_commits,
+			int append)
+{
+	struct packed_oid_list oids;
+	struct packed_commit_list commits;
+	struct hashfile *f;
+	uint32_t i, count_distinct = 0;
+	char *graph_name;
+	int fd;
+	struct lock_file lk = LOCK_INIT;
+	uint32_t chunk_ids[5];
+	uint64_t chunk_offsets[5];
+	int num_chunks;
+	int num_extra_edges;
+	struct commit_list *parent;
+
+	oids.nr = 0;
+	oids.alloc = approximate_object_count() / 4;
+
+	if (append) {
+		prepare_commit_graph_one(obj_dir);
+		if (commit_graph)
+			oids.alloc += commit_graph->num_commits;
+	}
+
+	if (oids.alloc < 1024)
+		oids.alloc = 1024;
+	ALLOC_ARRAY(oids.list, oids.alloc);
+
+	if (append && commit_graph) {
+		for (i = 0; i < commit_graph->num_commits; i++) {
+			const unsigned char *hash = commit_graph->chunk_oid_lookup +
+				commit_graph->hash_len * i;
+			hashcpy(oids.list[oids.nr++].hash, hash);
+		}
+	}
+
+	if (pack_indexes) {
+		struct strbuf packname = STRBUF_INIT;
+		int dirlen;
+		strbuf_addf(&packname, "%s/pack/", obj_dir);
+		dirlen = packname.len;
+		for (i = 0; i < nr_packs; i++) {
+			struct packed_git *p;
+			strbuf_setlen(&packname, dirlen);
+			strbuf_addstr(&packname, pack_indexes[i]);
+			p = add_packed_git(packname.buf, packname.len, 1);
+			if (!p)
+				die("error adding pack %s", packname.buf);
+			if (open_pack_index(p))
+				die("error opening index for %s", packname.buf);
+			for_each_object_in_pack(p, add_packed_commits, &oids);
+			close_pack(p);
+		}
+		strbuf_release(&packname);
+	}
+
+	if (commit_hex) {
+		for (i = 0; i < nr_commits; i++) {
+			const char *end;
+			struct object_id oid;
+			struct commit *result;
+
+			if (commit_hex[i] && parse_oid_hex(commit_hex[i], &oid, &end))
+				continue;
+
+			result = lookup_commit_reference_gently(&oid, 1);
+
+			if (result) {
+				ALLOC_GROW(oids.list, oids.nr + 1, oids.alloc);
+				oidcpy(&oids.list[oids.nr], &(result->object.oid));
+				oids.nr++;
+			}
+		}
+	}
+
+	if (!pack_indexes && !commit_hex)
+		for_each_packed_object(add_packed_commits, &oids, 0);
+
+	close_reachable(&oids);
+
+	QSORT(oids.list, oids.nr, commit_compare);
+
+	count_distinct = 1;
+	for (i = 1; i < oids.nr; i++) {
+		if (oidcmp(&oids.list[i-1], &oids.list[i]))
+			count_distinct++;
+	}
+
+	if (count_distinct >= GRAPH_PARENT_MISSING)
+		die(_("the commit graph format cannot write %d commits"), count_distinct);
+
+	commits.nr = 0;
+	commits.alloc = count_distinct;
+	ALLOC_ARRAY(commits.list, commits.alloc);
+
+	num_extra_edges = 0;
+	for (i = 0; i < oids.nr; i++) {
+		int num_parents = 0;
+		if (i > 0 && !oidcmp(&oids.list[i-1], &oids.list[i]))
+			continue;
+
+		commits.list[commits.nr] = lookup_commit(&oids.list[i]);
+		parse_commit(commits.list[commits.nr]);
+
+		for (parent = commits.list[commits.nr]->parents;
+		     parent; parent = parent->next)
+			num_parents++;
+
+		if (num_parents > 2)
+			num_extra_edges += num_parents - 1;
+
+		commits.nr++;
+	}
+	num_chunks = num_extra_edges ? 4 : 3;
+
+	if (commits.nr >= GRAPH_PARENT_MISSING)
+		die(_("too many commits to write graph"));
+
+	graph_name = get_commit_graph_filename(obj_dir);
+	fd = hold_lock_file_for_update(&lk, graph_name, 0);
+
+	if (fd < 0) {
+		struct strbuf folder = STRBUF_INIT;
+		strbuf_addstr(&folder, graph_name);
+		strbuf_setlen(&folder, strrchr(folder.buf, '/') - folder.buf);
+
+		if (mkdir(folder.buf, 0777) < 0)
+			die_errno(_("cannot mkdir %s"), folder.buf);
+		strbuf_release(&folder);
+
+		fd = hold_lock_file_for_update(&lk, graph_name, LOCK_DIE_ON_ERROR);
+
+		if (fd < 0)
+			die_errno("unable to create '%s'", graph_name);
+	}
+
+	f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
+
+	hashwrite_be32(f, GRAPH_SIGNATURE);
+
+	hashwrite_u8(f, GRAPH_VERSION);
+	hashwrite_u8(f, GRAPH_OID_VERSION);
+	hashwrite_u8(f, num_chunks);
+	hashwrite_u8(f, 0); /* unused padding byte */
+
+	chunk_ids[0] = GRAPH_CHUNKID_OIDFANOUT;
+	chunk_ids[1] = GRAPH_CHUNKID_OIDLOOKUP;
+	chunk_ids[2] = GRAPH_CHUNKID_DATA;
+	if (num_extra_edges)
+		chunk_ids[3] = GRAPH_CHUNKID_LARGEEDGES;
+	else
+		chunk_ids[3] = 0;
+	chunk_ids[4] = 0;
+
+	chunk_offsets[0] = 8 + (num_chunks + 1) * GRAPH_CHUNKLOOKUP_WIDTH;
+	chunk_offsets[1] = chunk_offsets[0] + GRAPH_FANOUT_SIZE;
+	chunk_offsets[2] = chunk_offsets[1] + GRAPH_OID_LEN * commits.nr;
+	chunk_offsets[3] = chunk_offsets[2] + (GRAPH_OID_LEN + 16) * commits.nr;
+	chunk_offsets[4] = chunk_offsets[3] + 4 * num_extra_edges;
+
+	for (i = 0; i <= num_chunks; i++) {
+		uint32_t chunk_write[3];
+
+		chunk_write[0] = htonl(chunk_ids[i]);
+		chunk_write[1] = htonl(chunk_offsets[i] >> 32);
+		chunk_write[2] = htonl(chunk_offsets[i] & 0xffffffff);
+		hashwrite(f, chunk_write, 12);
+	}
+
+	write_graph_chunk_fanout(f, commits.list, commits.nr);
+	write_graph_chunk_oids(f, GRAPH_OID_LEN, commits.list, commits.nr);
+	write_graph_chunk_data(f, GRAPH_OID_LEN, commits.list, commits.nr);
+	write_graph_chunk_large_edges(f, commits.list, commits.nr);
+
+	close_commit_graph();
+	finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC);
+	commit_lock_file(&lk);
+
+	free(oids.list);
+	oids.alloc = 0;
+	oids.nr = 0;
+}
diff --git a/commit-graph.h b/commit-graph.h
new file mode 100644
index 0000000..260a468
--- /dev/null
+++ b/commit-graph.h
@@ -0,0 +1,48 @@
+#ifndef COMMIT_GRAPH_H
+#define COMMIT_GRAPH_H
+
+#include "git-compat-util.h"
+
+char *get_commit_graph_filename(const char *obj_dir);
+
+/*
+ * Given a commit struct, try to fill the commit struct info, including:
+ *  1. tree object
+ *  2. date
+ *  3. parents.
+ *
+ * Returns 1 if and only if the commit was found in the packed graph.
+ *
+ * See parse_commit_buffer() for the fallback after this call.
+ */
+int parse_commit_in_graph(struct commit *item);
+
+struct tree *get_commit_tree_in_graph(const struct commit *c);
+
+struct commit_graph {
+	int graph_fd;
+
+	const unsigned char *data;
+	size_t data_len;
+
+	unsigned char hash_len;
+	unsigned char num_chunks;
+	uint32_t num_commits;
+	struct object_id oid;
+
+	const uint32_t *chunk_oid_fanout;
+	const unsigned char *chunk_oid_lookup;
+	const unsigned char *chunk_commit_data;
+	const unsigned char *chunk_large_edges;
+};
+
+struct commit_graph *load_commit_graph_one(const char *graph_file);
+
+void write_commit_graph(const char *obj_dir,
+			const char **pack_indexes,
+			int nr_packs,
+			const char **commit_hex,
+			int nr_commits,
+			int append);
+
+#endif
diff --git a/commit.c b/commit.c
index ca474a7..b0e57cc 100644
--- a/commit.c
+++ b/commit.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "tag.h"
 #include "commit.h"
+#include "commit-graph.h"
 #include "pkt-line.h"
 #include "utf8.h"
 #include "diff.h"
@@ -12,6 +13,7 @@
 #include "prio-queue.h"
 #include "sha1-lookup.h"
 #include "wt-status.h"
+#include "advice.h"
 
 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
 
@@ -176,6 +178,15 @@
 	struct strbuf buf = STRBUF_INIT;
 	if (!fp)
 		return -1;
+	if (advice_graft_file_deprecated)
+		advise(_("Support for <GIT_DIR>/info/grafts is deprecated\n"
+			 "and will be removed in a future Git version.\n"
+			 "\n"
+			 "Please use \"git replace --convert-graft-file\"\n"
+			 "to convert the grafts into replace refs.\n"
+			 "\n"
+			 "Turn this message off by running\n"
+			 "\"git config advice.graftFileDeprecated false\""));
 	while (!strbuf_getwholeline(&buf, fp, '\n')) {
 		/* The format is just "Commit Parent1 Parent2 ...\n" */
 		struct commit_graft *graft = read_graft_line(&buf);
@@ -295,6 +306,22 @@
 	}
 }
 
+struct tree *get_commit_tree(const struct commit *commit)
+{
+	if (commit->maybe_tree || !commit->object.parsed)
+		return commit->maybe_tree;
+
+	if (commit->graph_pos == COMMIT_NOT_FROM_GRAPH)
+		BUG("commit has NULL tree, but was not loaded from commit-graph");
+
+	return get_commit_tree_in_graph(commit);
+}
+
+struct object_id *get_commit_tree_oid(const struct commit *commit)
+{
+	return &get_commit_tree(commit)->object.oid;
+}
+
 const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 {
 	struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit);
@@ -331,10 +358,10 @@
 	if (tail <= bufptr + tree_entry_len + 1 || memcmp(bufptr, "tree ", 5) ||
 			bufptr[tree_entry_len] != '\n')
 		return error("bogus commit object %s", oid_to_hex(&item->object.oid));
-	if (get_sha1_hex(bufptr + 5, parent.hash) < 0)
+	if (get_oid_hex(bufptr + 5, &parent) < 0)
 		return error("bad tree pointer in commit %s",
 			     oid_to_hex(&item->object.oid));
-	item->tree = lookup_tree(&parent);
+	item->maybe_tree = lookup_tree(&parent);
 	bufptr += tree_entry_len + 1; /* "tree " + "hex sha1" + "\n" */
 	pptr = &item->parents;
 
@@ -343,7 +370,7 @@
 		struct commit *new_parent;
 
 		if (tail <= bufptr + parent_entry_len + 1 ||
-		    get_sha1_hex(bufptr + 7, parent.hash) ||
+		    get_oid_hex(bufptr + 7, &parent) ||
 		    bufptr[parent_entry_len] != '\n')
 			return error("bad parents in commit %s", oid_to_hex(&item->object.oid));
 		bufptr += parent_entry_len + 1;
@@ -383,6 +410,8 @@
 		return -1;
 	if (item->object.parsed)
 		return 0;
+	if (parse_commit_in_graph(item))
+		return 0;
 	buffer = read_object_file(&item->object.oid, &type, &size);
 	if (!buffer)
 		return quiet_on_missing ? -1 :
@@ -1288,17 +1317,19 @@
 	return extra;
 }
 
-void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
+int for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
 {
 	struct commit_extra_header *extra, *to_free;
+	int res = 0;
 
 	to_free = read_commit_extra_headers(commit, NULL);
-	for (extra = to_free; extra; extra = extra->next) {
+	for (extra = to_free; !res && extra; extra = extra->next) {
 		if (strcmp(extra->key, "mergetag"))
 			continue; /* not a merge tag */
-		fn(commit, extra, data);
+		res = fn(commit, extra, data);
 	}
 	free_commit_extra_headers(to_free);
+	return res;
 }
 
 static inline int standard_header_field(const char *field, size_t len)
diff --git a/commit.h b/commit.h
index 0fb8271..c3af512 100644
--- a/commit.h
+++ b/commit.h
@@ -9,6 +9,8 @@
 #include "string-list.h"
 #include "pretty.h"
 
+#define COMMIT_NOT_FROM_GRAPH 0xFFFFFFFF
+
 struct commit_list {
 	struct commit *item;
 	struct commit_list *next;
@@ -17,10 +19,17 @@
 struct commit {
 	struct object object;
 	void *util;
-	unsigned int index;
 	timestamp_t date;
 	struct commit_list *parents;
-	struct tree *tree;
+
+	/*
+	 * If the commit is loaded from the commit-graph file, then this
+	 * member may be NULL. Only access it through get_commit_tree()
+	 * or get_commit_tree_oid().
+	 */
+	struct tree *maybe_tree;
+	uint32_t graph_pos;
+	unsigned int index;
 };
 
 extern int save_commit_buffer;
@@ -99,6 +108,9 @@
  */
 void free_commit_buffer(struct commit *);
 
+struct tree *get_commit_tree(const struct commit *);
+struct object_id *get_commit_tree_oid(const struct commit *);
+
 /*
  * Disassociate any cached object buffer from the commit, but do not free it.
  * The buffer (or NULL, if none) is returned.
@@ -291,10 +303,10 @@
 /* Find the end of the log message, the right place for a new trailer. */
 extern int ignore_non_trailer(const char *buf, size_t len);
 
-typedef void (*each_mergetag_fn)(struct commit *commit, struct commit_extra_header *extra,
+typedef int (*each_mergetag_fn)(struct commit *commit, struct commit_extra_header *extra,
 				 void *cb_data);
 
-extern void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data);
+extern int for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data);
 
 struct merge_remote_desc {
 	struct object *obj; /* the named object, could be a tag */
diff --git a/common-main.c b/common-main.c
index b989e13..3728f66 100644
--- a/common-main.c
+++ b/common-main.c
@@ -32,14 +32,14 @@
 	 */
 	sanitize_stdfds();
 
+	git_resolve_executable_dir(argv[0]);
+
 	git_setup_gettext();
 
 	initialize_the_repository();
 
 	attr_start();
 
-	git_extract_argv0_path(argv[0]);
-
 	restore_sigpipe_to_default();
 
 	return cmd_main(argc, argv);
diff --git a/compat/mingw.c b/compat/mingw.c
index a67872b..6ded1c8 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -2221,7 +2221,7 @@
 		die_startup();
 
 	/* determine size of argv and environ conversion buffer */
-	maxlen = wcslen(_wpgmptr);
+	maxlen = wcslen(wargv[0]);
 	for (i = 1; i < argc; i++)
 		maxlen = max(maxlen, wcslen(wargv[i]));
 	for (i = 0; wenv[i]; i++)
@@ -2241,8 +2241,7 @@
 	buffer = malloc_startup(maxlen);
 
 	/* convert command line arguments and environment to UTF-8 */
-	__argv[0] = wcstoutfdup_startup(buffer, _wpgmptr, maxlen);
-	for (i = 1; i < argc; i++)
+	for (i = 0; i < argc; i++)
 		__argv[i] = wcstoutfdup_startup(buffer, wargv[i], maxlen);
 	for (i = 0; wenv[i]; i++)
 		environ[i] = wcstoutfdup_startup(buffer, wenv[i], maxlen);
diff --git a/config.c b/config.c
index 62c5609..fbbf0f8 100644
--- a/config.c
+++ b/config.c
@@ -16,6 +16,7 @@
 #include "string-list.h"
 #include "utf8.h"
 #include "dir.h"
+#include "color.h"
 
 struct config_source {
 	struct config_source *prev;
@@ -102,7 +103,7 @@
 	if (conf->u.buf.pos > 0) {
 		conf->u.buf.pos--;
 		if (conf->u.buf.buf[conf->u.buf.pos] != c)
-			die("BUG: config_buf can only ungetc the same character");
+			BUG("config_buf can only ungetc the same character");
 		return c;
 	}
 
@@ -189,7 +190,7 @@
 		strbuf_realpath(&path, cf->path, 1);
 		slash = find_last_dir_sep(path.buf);
 		if (!slash)
-			die("BUG: how is this possible?");
+			BUG("how is this possible?");
 		strbuf_splice(pat, 0, 1, path.buf, slash - path.buf);
 		prefix = slash - path.buf + 1 /* slash */;
 	} else if (!is_absolute_path(pat->buf))
@@ -653,7 +654,45 @@
 	}
 }
 
-static int git_parse_source(config_fn_t fn, void *data)
+struct parse_event_data {
+	enum config_event_t previous_type;
+	size_t previous_offset;
+	const struct config_options *opts;
+};
+
+static int do_event(enum config_event_t type, struct parse_event_data *data)
+{
+	size_t offset;
+
+	if (!data->opts || !data->opts->event_fn)
+		return 0;
+
+	if (type == CONFIG_EVENT_WHITESPACE &&
+	    data->previous_type == type)
+		return 0;
+
+	offset = cf->do_ftell(cf);
+	/*
+	 * At EOF, the parser always "inserts" an extra '\n', therefore
+	 * the end offset of the event is the current file position, otherwise
+	 * we will already have advanced to the next event.
+	 */
+	if (type != CONFIG_EVENT_EOF)
+		offset--;
+
+	if (data->previous_type != CONFIG_EVENT_EOF &&
+	    data->opts->event_fn(data->previous_type, data->previous_offset,
+				 offset, data->opts->event_fn_data) < 0)
+		return -1;
+
+	data->previous_type = type;
+	data->previous_offset = offset;
+
+	return 0;
+}
+
+static int git_parse_source(config_fn_t fn, void *data,
+			    const struct config_options *opts)
 {
 	int comment = 0;
 	int baselen = 0;
@@ -664,8 +703,15 @@
 	/* U+FEFF Byte Order Mark in UTF8 */
 	const char *bomptr = utf8_bom;
 
+	/* For the parser event callback */
+	struct parse_event_data event_data = {
+		CONFIG_EVENT_EOF, 0, opts
+	};
+
 	for (;;) {
-		int c = get_next_char();
+		int c;
+
+		c = get_next_char();
 		if (bomptr && *bomptr) {
 			/* We are at the file beginning; skip UTF8-encoded BOM
 			 * if present. Sane editors won't put this in on their
@@ -682,18 +728,33 @@
 			}
 		}
 		if (c == '\n') {
-			if (cf->eof)
+			if (cf->eof) {
+				if (do_event(CONFIG_EVENT_EOF, &event_data) < 0)
+					return -1;
 				return 0;
+			}
+			if (do_event(CONFIG_EVENT_WHITESPACE, &event_data) < 0)
+				return -1;
 			comment = 0;
 			continue;
 		}
-		if (comment || isspace(c))
+		if (comment)
 			continue;
+		if (isspace(c)) {
+			if (do_event(CONFIG_EVENT_WHITESPACE, &event_data) < 0)
+					return -1;
+			continue;
+		}
 		if (c == '#' || c == ';') {
+			if (do_event(CONFIG_EVENT_COMMENT, &event_data) < 0)
+					return -1;
 			comment = 1;
 			continue;
 		}
 		if (c == '[') {
+			if (do_event(CONFIG_EVENT_SECTION, &event_data) < 0)
+					return -1;
+
 			/* Reset prior to determining a new stem */
 			strbuf_reset(var);
 			if (get_base_var(var) < 0 || var->len < 1)
@@ -704,6 +765,10 @@
 		}
 		if (!isalpha(c))
 			break;
+
+		if (do_event(CONFIG_EVENT_ENTRY, &event_data) < 0)
+			return -1;
+
 		/*
 		 * Truncate the var name back to the section header
 		 * stem prior to grabbing the suffix part of the name
@@ -715,6 +780,9 @@
 			break;
 	}
 
+	if (do_event(CONFIG_EVENT_ERROR, &event_data) < 0)
+		return -1;
+
 	switch (cf->origin_type) {
 	case CONFIG_ORIGIN_BLOB:
 		error_msg = xstrfmt(_("bad config line %d in blob %s"),
@@ -1000,6 +1068,15 @@
 	return 0;
 }
 
+int git_config_color(char *dest, const char *var, const char *value)
+{
+	if (!value)
+		return config_error_nonbool(var);
+	if (color_parse(value, dest) < 0)
+		return -1;
+	return 0;
+}
+
 static int git_default_core_config(const char *var, const char *value)
 {
 	/* This needs a better name */
@@ -1172,6 +1249,11 @@
 		return 0;
 	}
 
+	if (!strcmp(var, "core.checkroundtripencoding")) {
+		check_roundtrip_encoding = xstrdup(value);
+		return 0;
+	}
+
 	if (!strcmp(var, "core.notesref")) {
 		notes_ref_name = xstrdup(value);
 		return 0;
@@ -1226,6 +1308,11 @@
 		return 0;
 	}
 
+	if (!strcmp(var, "core.commitgraph")) {
+		core_commit_graph = git_config_bool(var, value);
+		return 0;
+	}
+
 	if (!strcmp(var, "core.sparsecheckout")) {
 		core_apply_sparse_checkout = git_config_bool(var, value);
 		return 0;
@@ -1365,7 +1452,7 @@
 	if (starts_with(var, "mailmap."))
 		return git_default_mailmap_config(var, value);
 
-	if (starts_with(var, "advice."))
+	if (starts_with(var, "advice.") || starts_with(var, "color.advice"))
 		return git_default_advice_config(var, value);
 
 	if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
@@ -1398,7 +1485,8 @@
  * fgetc, ungetc, ftell of top need to be initialized before calling
  * this function.
  */
-static int do_config_from(struct config_source *top, config_fn_t fn, void *data)
+static int do_config_from(struct config_source *top, config_fn_t fn, void *data,
+			  const struct config_options *opts)
 {
 	int ret;
 
@@ -1410,7 +1498,7 @@
 	strbuf_init(&top->var, 1024);
 	cf = top;
 
-	ret = git_parse_source(fn, data);
+	ret = git_parse_source(fn, data, opts);
 
 	/* pop config-file parsing state stack */
 	strbuf_release(&top->value);
@@ -1423,7 +1511,7 @@
 static int do_config_from_file(config_fn_t fn,
 		const enum config_origin_type origin_type,
 		const char *name, const char *path, FILE *f,
-		void *data)
+		void *data, const struct config_options *opts)
 {
 	struct config_source top;
 	int ret;
@@ -1438,29 +1526,38 @@
 	top.do_ftell = config_file_ftell;
 
 	flockfile(f);
-	ret = do_config_from(&top, fn, data);
+	ret = do_config_from(&top, fn, data, opts);
 	funlockfile(f);
 	return ret;
 }
 
 static int git_config_from_stdin(config_fn_t fn, void *data)
 {
-	return do_config_from_file(fn, CONFIG_ORIGIN_STDIN, "", NULL, stdin, data);
+	return do_config_from_file(fn, CONFIG_ORIGIN_STDIN, "", NULL, stdin,
+				   data, NULL);
 }
 
-int git_config_from_file(config_fn_t fn, const char *filename, void *data)
+int git_config_from_file_with_options(config_fn_t fn, const char *filename,
+				      void *data,
+				      const struct config_options *opts)
 {
 	int ret = -1;
 	FILE *f;
 
 	f = fopen_or_warn(filename, "r");
 	if (f) {
-		ret = do_config_from_file(fn, CONFIG_ORIGIN_FILE, filename, filename, f, data);
+		ret = do_config_from_file(fn, CONFIG_ORIGIN_FILE, filename,
+					  filename, f, data, opts);
 		fclose(f);
 	}
 	return ret;
 }
 
+int git_config_from_file(config_fn_t fn, const char *filename, void *data)
+{
+	return git_config_from_file_with_options(fn, filename, data, NULL);
+}
+
 int git_config_from_mem(config_fn_t fn, const enum config_origin_type origin_type,
 			const char *name, const char *buf, size_t len, void *data)
 {
@@ -1477,7 +1574,7 @@
 	top.do_ungetc = config_buf_ungetc;
 	top.do_ftell = config_buf_ftell;
 
-	return do_config_from(&top, fn, data);
+	return do_config_from(&top, fn, data, NULL);
 }
 
 int git_config_from_blob_oid(config_fn_t fn,
@@ -1717,7 +1814,7 @@
 	l_item->value_index = e->value_list.nr - 1;
 
 	if (!cf)
-		die("BUG: configset_add_value has no source");
+		BUG("configset_add_value has no source");
 	if (cf->name) {
 		kv_info->filename = strintern(cf->name);
 		kv_info->linenr = cf->linenr;
@@ -2221,96 +2318,111 @@
  * Find all the stuff for git_config_set() below.
  */
 
-static struct {
+struct config_store_data {
 	int baselen;
 	char *key;
 	int do_not_match;
 	regex_t *value_regex;
 	int multi_replace;
-	size_t *offset;
-	unsigned int offset_alloc;
-	enum { START, SECTION_SEEN, SECTION_END_SEEN, KEY_SEEN } state;
-	unsigned int seen;
-} store;
+	struct {
+		size_t begin, end;
+		enum config_event_t type;
+		int is_keys_section;
+	} *parsed;
+	unsigned int parsed_nr, parsed_alloc, *seen, seen_nr, seen_alloc;
+	unsigned int key_seen:1, section_seen:1, is_keys_section:1;
+};
 
-static int matches(const char *key, const char *value)
+static void config_store_data_clear(struct config_store_data *store)
 {
-	if (strcmp(key, store.key))
+	free(store->key);
+	if (store->value_regex != NULL &&
+	    store->value_regex != CONFIG_REGEX_NONE) {
+		regfree(store->value_regex);
+		free(store->value_regex);
+	}
+	free(store->parsed);
+	free(store->seen);
+	memset(store, 0, sizeof(*store));
+}
+
+static int matches(const char *key, const char *value,
+		   const struct config_store_data *store)
+{
+	if (strcmp(key, store->key))
 		return 0; /* not ours */
-	if (!store.value_regex)
+	if (!store->value_regex)
 		return 1; /* always matches */
-	if (store.value_regex == CONFIG_REGEX_NONE)
+	if (store->value_regex == CONFIG_REGEX_NONE)
 		return 0; /* never matches */
 
-	return store.do_not_match ^
-		(value && !regexec(store.value_regex, value, 0, NULL, 0));
+	return store->do_not_match ^
+		(value && !regexec(store->value_regex, value, 0, NULL, 0));
+}
+
+static int store_aux_event(enum config_event_t type,
+			   size_t begin, size_t end, void *data)
+{
+	struct config_store_data *store = data;
+
+	ALLOC_GROW(store->parsed, store->parsed_nr + 1, store->parsed_alloc);
+	store->parsed[store->parsed_nr].begin = begin;
+	store->parsed[store->parsed_nr].end = end;
+	store->parsed[store->parsed_nr].type = type;
+
+	if (type == CONFIG_EVENT_SECTION) {
+		if (cf->var.len < 2 || cf->var.buf[cf->var.len - 1] != '.')
+			return error("invalid section name '%s'", cf->var.buf);
+
+		/* Is this the section we were looking for? */
+		store->is_keys_section =
+			store->parsed[store->parsed_nr].is_keys_section =
+			cf->var.len - 1 == store->baselen &&
+			!strncasecmp(cf->var.buf, store->key, store->baselen);
+		if (store->is_keys_section) {
+			store->section_seen = 1;
+			ALLOC_GROW(store->seen, store->seen_nr + 1,
+				   store->seen_alloc);
+			store->seen[store->seen_nr] = store->parsed_nr;
+		}
+	}
+
+	store->parsed_nr++;
+
+	return 0;
 }
 
 static int store_aux(const char *key, const char *value, void *cb)
 {
-	const char *ep;
-	size_t section_len;
+	struct config_store_data *store = cb;
 
-	switch (store.state) {
-	case KEY_SEEN:
-		if (matches(key, value)) {
-			if (store.seen == 1 && store.multi_replace == 0) {
+	if (store->key_seen) {
+		if (matches(key, value, store)) {
+			if (store->seen_nr == 1 && store->multi_replace == 0) {
 				warning(_("%s has multiple values"), key);
 			}
 
-			ALLOC_GROW(store.offset, store.seen + 1,
-				   store.offset_alloc);
+			ALLOC_GROW(store->seen, store->seen_nr + 1,
+				   store->seen_alloc);
 
-			store.offset[store.seen] = cf->do_ftell(cf);
-			store.seen++;
+			store->seen[store->seen_nr] = store->parsed_nr;
+			store->seen_nr++;
 		}
-		break;
-	case SECTION_SEEN:
+	} else if (store->is_keys_section) {
 		/*
-		 * What we are looking for is in store.key (both
-		 * section and var), and its section part is baselen
-		 * long.  We found key (again, both section and var).
-		 * We would want to know if this key is in the same
-		 * section as what we are looking for.  We already
-		 * know we are in the same section as what should
-		 * hold store.key.
+		 * Do not increment matches yet: this may not be a match, but we
+		 * are in the desired section.
 		 */
-		ep = strrchr(key, '.');
-		section_len = ep - key;
+		ALLOC_GROW(store->seen, store->seen_nr + 1, store->seen_alloc);
+		store->seen[store->seen_nr] = store->parsed_nr;
+		store->section_seen = 1;
 
-		if ((section_len != store.baselen) ||
-		    memcmp(key, store.key, section_len+1)) {
-			store.state = SECTION_END_SEEN;
-			break;
-		}
-
-		/*
-		 * Do not increment matches: this is no match, but we
-		 * just made sure we are in the desired section.
-		 */
-		ALLOC_GROW(store.offset, store.seen + 1,
-			   store.offset_alloc);
-		store.offset[store.seen] = cf->do_ftell(cf);
-		/* fallthru */
-	case SECTION_END_SEEN:
-	case START:
-		if (matches(key, value)) {
-			ALLOC_GROW(store.offset, store.seen + 1,
-				   store.offset_alloc);
-			store.offset[store.seen] = cf->do_ftell(cf);
-			store.state = KEY_SEEN;
-			store.seen++;
-		} else {
-			if (strrchr(key, '.') - key == store.baselen &&
-			      !strncmp(key, store.key, store.baselen)) {
-					store.state = SECTION_SEEN;
-					ALLOC_GROW(store.offset,
-						   store.seen + 1,
-						   store.offset_alloc);
-					store.offset[store.seen] = cf->do_ftell(cf);
-			}
+		if (matches(key, value, store)) {
+			store->seen_nr++;
+			store->key_seen = 1;
 		}
 	}
+
 	return 0;
 }
 
@@ -2322,31 +2434,33 @@
 	return 4;
 }
 
-static struct strbuf store_create_section(const char *key)
+static struct strbuf store_create_section(const char *key,
+					  const struct config_store_data *store)
 {
 	const char *dot;
 	int i;
 	struct strbuf sb = STRBUF_INIT;
 
-	dot = memchr(key, '.', store.baselen);
+	dot = memchr(key, '.', store->baselen);
 	if (dot) {
 		strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
-		for (i = dot - key + 1; i < store.baselen; i++) {
+		for (i = dot - key + 1; i < store->baselen; i++) {
 			if (key[i] == '"' || key[i] == '\\')
 				strbuf_addch(&sb, '\\');
 			strbuf_addch(&sb, key[i]);
 		}
 		strbuf_addstr(&sb, "\"]\n");
 	} else {
-		strbuf_addf(&sb, "[%.*s]\n", store.baselen, key);
+		strbuf_addf(&sb, "[%.*s]\n", store->baselen, key);
 	}
 
 	return sb;
 }
 
-static ssize_t write_section(int fd, const char *key)
+static ssize_t write_section(int fd, const char *key,
+			     const struct config_store_data *store)
 {
-	struct strbuf sb = store_create_section(key);
+	struct strbuf sb = store_create_section(key, store);
 	ssize_t ret;
 
 	ret = write_in_full(fd, sb.buf, sb.len);
@@ -2355,11 +2469,12 @@
 	return ret;
 }
 
-static ssize_t write_pair(int fd, const char *key, const char *value)
+static ssize_t write_pair(int fd, const char *key, const char *value,
+			  const struct config_store_data *store)
 {
 	int i;
 	ssize_t ret;
-	int length = strlen(key + store.baselen + 1);
+	int length = strlen(key + store->baselen + 1);
 	const char *quote = "";
 	struct strbuf sb = STRBUF_INIT;
 
@@ -2379,7 +2494,7 @@
 		quote = "\"";
 
 	strbuf_addf(&sb, "\t%.*s = %s",
-		    length, key + store.baselen + 1, quote);
+		    length, key + store->baselen + 1, quote);
 
 	for (i = 0; value[i]; i++)
 		switch (value[i]) {
@@ -2405,30 +2520,85 @@
 	return ret;
 }
 
-static ssize_t find_beginning_of_line(const char *contents, size_t size,
-	size_t offset_, int *found_bracket)
+/*
+ * If we are about to unset the last key(s) in a section, and if there are
+ * no comments surrounding (or included in) the section, we will want to
+ * extend begin/end to remove the entire section.
+ *
+ * Note: the parameter `seen_ptr` points to the index into the store.seen
+ * array.  * This index may be incremented if a section has more than one
+ * entry (which all are to be removed).
+ */
+static void maybe_remove_section(struct config_store_data *store,
+				 const char *contents,
+				 size_t *begin_offset, size_t *end_offset,
+				 int *seen_ptr)
 {
-	size_t equal_offset = size, bracket_offset = size;
-	ssize_t offset;
+	size_t begin;
+	int i, seen, section_seen = 0;
 
-contline:
-	for (offset = offset_-2; offset > 0
-			&& contents[offset] != '\n'; offset--)
-		switch (contents[offset]) {
-			case '=': equal_offset = offset; break;
-			case ']': bracket_offset = offset; break;
+	/*
+	 * First, ensure that this is the first key, and that there are no
+	 * comments before the entry nor before the section header.
+	 */
+	seen = *seen_ptr;
+	for (i = store->seen[seen]; i > 0; i--) {
+		enum config_event_t type = store->parsed[i - 1].type;
+
+		if (type == CONFIG_EVENT_COMMENT)
+			/* There is a comment before this entry or section */
+			return;
+		if (type == CONFIG_EVENT_ENTRY) {
+			if (!section_seen)
+				/* This is not the section's first entry. */
+				return;
+			/* We encountered no comment before the section. */
+			break;
 		}
-	if (offset > 0 && contents[offset-1] == '\\') {
-		offset_ = offset;
-		goto contline;
+		if (type == CONFIG_EVENT_SECTION) {
+			if (!store->parsed[i - 1].is_keys_section)
+				break;
+			section_seen = 1;
+		}
 	}
-	if (bracket_offset < equal_offset) {
-		*found_bracket = 1;
-		offset = bracket_offset+1;
-	} else
-		offset++;
+	begin = store->parsed[i].begin;
 
-	return offset;
+	/*
+	 * Next, make sure that we are removing he last key(s) in the section,
+	 * and that there are no comments that are possibly about the current
+	 * section.
+	 */
+	for (i = store->seen[seen] + 1; i < store->parsed_nr; i++) {
+		enum config_event_t type = store->parsed[i].type;
+
+		if (type == CONFIG_EVENT_COMMENT)
+			return;
+		if (type == CONFIG_EVENT_SECTION) {
+			if (store->parsed[i].is_keys_section)
+				continue;
+			break;
+		}
+		if (type == CONFIG_EVENT_ENTRY) {
+			if (++seen < store->seen_nr &&
+			    i == store->seen[seen])
+				/* We want to remove this entry, too */
+				continue;
+			/* There is another entry in this section. */
+			return;
+		}
+	}
+
+	/*
+	 * We are really removing the last entry/entries from this section, and
+	 * there are no enclosed or surrounding comments. Remove the entire,
+	 * now-empty section.
+	 */
+	*seen_ptr = seen;
+	*begin_offset = begin;
+	if (i < store->parsed_nr)
+		*end_offset = store->parsed[i].begin;
+	else
+		*end_offset = store->parsed[store->parsed_nr - 1].end;
 }
 
 int git_config_set_in_file_gently(const char *config_filename,
@@ -2489,6 +2659,9 @@
 	char *filename_buf = NULL;
 	char *contents = NULL;
 	size_t contents_sz;
+	struct config_store_data store;
+
+	memset(&store, 0, sizeof(store));
 
 	/* parse-key returns negative; flip the sign to feed exit(3) */
 	ret = 0 - git_config_parse_key(key, &store.key, &store.baselen);
@@ -2507,7 +2680,6 @@
 	fd = hold_lock_file_for_update(&lock, config_filename, 0);
 	if (fd < 0) {
 		error_errno("could not lock config file %s", config_filename);
-		free(store.key);
 		ret = CONFIG_NO_LOCK;
 		goto out_free;
 	}
@@ -2517,8 +2689,6 @@
 	 */
 	in_fd = open(config_filename, O_RDONLY);
 	if ( in_fd < 0 ) {
-		free(store.key);
-
 		if ( ENOENT != errno ) {
 			error_errno("opening %s", config_filename);
 			ret = CONFIG_INVALID_FILE; /* same as "invalid config file" */
@@ -2530,14 +2700,16 @@
 			goto out_free;
 		}
 
-		store.key = (char *)key;
-		if (write_section(fd, key) < 0 ||
-		    write_pair(fd, key, value) < 0)
+		free(store.key);
+		store.key = xstrdup(key);
+		if (write_section(fd, key, &store) < 0 ||
+		    write_pair(fd, key, value, &store) < 0)
 			goto write_err_out;
 	} else {
 		struct stat st;
 		size_t copy_begin, copy_end;
 		int i, new_line = 0;
+		struct config_options opts;
 
 		if (value_regex == NULL)
 			store.value_regex = NULL;
@@ -2554,45 +2726,38 @@
 			if (regcomp(store.value_regex, value_regex,
 					REG_EXTENDED)) {
 				error("invalid pattern: %s", value_regex);
-				free(store.value_regex);
+				FREE_AND_NULL(store.value_regex);
 				ret = CONFIG_INVALID_PATTERN;
 				goto out_free;
 			}
 		}
 
-		ALLOC_GROW(store.offset, 1, store.offset_alloc);
-		store.offset[0] = 0;
-		store.state = START;
-		store.seen = 0;
+		ALLOC_GROW(store.parsed, 1, store.parsed_alloc);
+		store.parsed[0].end = 0;
+
+		memset(&opts, 0, sizeof(opts));
+		opts.event_fn = store_aux_event;
+		opts.event_fn_data = &store;
 
 		/*
-		 * After this, store.offset will contain the *end* offset
-		 * of the last match, or remain at 0 if no match was found.
+		 * After this, store.parsed will contain offsets of all the
+		 * parsed elements, and store.seen will contain a list of
+		 * matches, as indices into store.parsed.
+		 *
 		 * As a side effect, we make sure to transform only a valid
 		 * existing config file.
 		 */
-		if (git_config_from_file(store_aux, config_filename, NULL)) {
+		if (git_config_from_file_with_options(store_aux,
+						      config_filename,
+						      &store, &opts)) {
 			error("invalid config file %s", config_filename);
-			free(store.key);
-			if (store.value_regex != NULL &&
-			    store.value_regex != CONFIG_REGEX_NONE) {
-				regfree(store.value_regex);
-				free(store.value_regex);
-			}
 			ret = CONFIG_INVALID_FILE;
 			goto out_free;
 		}
 
-		free(store.key);
-		if (store.value_regex != NULL &&
-		    store.value_regex != CONFIG_REGEX_NONE) {
-			regfree(store.value_regex);
-			free(store.value_regex);
-		}
-
 		/* if nothing to unset, or too many matches, error out */
-		if ((store.seen == 0 && value == NULL) ||
-				(store.seen > 1 && multi_replace == 0)) {
+		if ((store.seen_nr == 0 && value == NULL) ||
+		    (store.seen_nr > 1 && multi_replace == 0)) {
 			ret = CONFIG_NOTHING_SET;
 			goto out_free;
 		}
@@ -2623,18 +2788,49 @@
 			goto out_free;
 		}
 
-		if (store.seen == 0)
-			store.seen = 1;
+		if (store.seen_nr == 0) {
+			if (!store.seen_alloc) {
+				/* Did not see key nor section */
+				ALLOC_GROW(store.seen, 1, store.seen_alloc);
+				store.seen[0] = store.parsed_nr
+					- !!store.parsed_nr;
+			}
+			store.seen_nr = 1;
+		}
 
-		for (i = 0, copy_begin = 0; i < store.seen; i++) {
-			if (store.offset[i] == 0) {
-				store.offset[i] = copy_end = contents_sz;
-			} else if (store.state != KEY_SEEN) {
-				copy_end = store.offset[i];
-			} else
-				copy_end = find_beginning_of_line(
-					contents, contents_sz,
-					store.offset[i]-2, &new_line);
+		for (i = 0, copy_begin = 0; i < store.seen_nr; i++) {
+			size_t replace_end;
+			int j = store.seen[i];
+
+			new_line = 0;
+			if (!store.key_seen) {
+				copy_end = store.parsed[j].end;
+				/* include '\n' when copying section header */
+				if (copy_end > 0 && copy_end < contents_sz &&
+				    contents[copy_end - 1] != '\n' &&
+				    contents[copy_end] == '\n')
+					copy_end++;
+				replace_end = copy_end;
+			} else {
+				replace_end = store.parsed[j].end;
+				copy_end = store.parsed[j].begin;
+				if (!value)
+					maybe_remove_section(&store, contents,
+							     &copy_end,
+							     &replace_end, &i);
+				/*
+				 * Swallow preceding white-space on the same
+				 * line.
+				 */
+				while (copy_end > 0 ) {
+					char c = contents[copy_end - 1];
+
+					if (isspace(c) && c != '\n')
+						copy_end--;
+					else
+						break;
+				}
+			}
 
 			if (copy_end > 0 && contents[copy_end-1] != '\n')
 				new_line = 1;
@@ -2648,16 +2844,16 @@
 				    write_str_in_full(fd, "\n") < 0)
 					goto write_err_out;
 			}
-			copy_begin = store.offset[i];
+			copy_begin = replace_end;
 		}
 
 		/* write the pair (value == NULL means unset) */
 		if (value != NULL) {
-			if (store.state == START) {
-				if (write_section(fd, key) < 0)
+			if (!store.section_seen) {
+				if (write_section(fd, key, &store) < 0)
 					goto write_err_out;
 			}
-			if (write_pair(fd, key, value) < 0)
+			if (write_pair(fd, key, value, &store) < 0)
 				goto write_err_out;
 		}
 
@@ -2689,6 +2885,7 @@
 		munmap(contents, contents_sz);
 	if (in_fd >= 0)
 		close(in_fd);
+	config_store_data_clear(&store);
 	return ret;
 
 write_err_out:
@@ -2781,7 +2978,8 @@
 
 /* if new_name == NULL, the section is removed instead */
 static int git_config_copy_or_rename_section_in_file(const char *config_filename,
-				      const char *old_name, const char *new_name, int copy)
+				      const char *old_name,
+				      const char *new_name, int copy)
 {
 	int ret = 0, remove = 0;
 	char *filename_buf = NULL;
@@ -2791,6 +2989,9 @@
 	FILE *config_file = NULL;
 	struct stat st;
 	struct strbuf copystr = STRBUF_INIT;
+	struct config_store_data store;
+
+	memset(&store, 0, sizeof(store));
 
 	if (new_name && !section_name_is_ok(new_name)) {
 		ret = error("invalid section name: %s", new_name);
@@ -2860,7 +3061,7 @@
 				}
 				store.baselen = strlen(new_name);
 				if (!copy) {
-					if (write_section(out_fd, new_name) < 0) {
+					if (write_section(out_fd, new_name, &store) < 0) {
 						ret = write_error(get_lock_file_path(&lock));
 						goto out;
 					}
@@ -2881,7 +3082,7 @@
 						output[0] = '\t';
 					}
 				} else {
-					copystr = store_create_section(new_name);
+					copystr = store_create_section(new_name, &store);
 				}
 			}
 			remove = 0;
@@ -2925,6 +3126,7 @@
 	rollback_lock_file(&lock);
 out_no_rollback:
 	free(filename_buf);
+	config_store_data_clear(&store);
 	return ret;
 }
 
@@ -3006,7 +3208,7 @@
 	else if(cf)
 		type = cf->origin_type;
 	else
-		die("BUG: current_config_origin_type called outside config callback");
+		BUG("current_config_origin_type called outside config callback");
 
 	switch (type) {
 	case CONFIG_ORIGIN_BLOB:
@@ -3020,7 +3222,7 @@
 	case CONFIG_ORIGIN_CMDLINE:
 		return "command line";
 	default:
-		die("BUG: unknown config origin type");
+		BUG("unknown config origin type");
 	}
 }
 
@@ -3032,7 +3234,7 @@
 	else if (cf)
 		name = cf->name;
 	else
-		die("BUG: current_config_name called outside config callback");
+		BUG("current_config_name called outside config callback");
 	return name ? name : "";
 }
 
diff --git a/config.h b/config.h
index ef70a9c..cdac2fc 100644
--- a/config.h
+++ b/config.h
@@ -28,15 +28,40 @@
 	CONFIG_ORIGIN_CMDLINE
 };
 
+enum config_event_t {
+	CONFIG_EVENT_SECTION,
+	CONFIG_EVENT_ENTRY,
+	CONFIG_EVENT_WHITESPACE,
+	CONFIG_EVENT_COMMENT,
+	CONFIG_EVENT_EOF,
+	CONFIG_EVENT_ERROR
+};
+
+/*
+ * The parser event function (if not NULL) is called with the event type and
+ * the begin/end offsets of the parsed elements.
+ *
+ * Note: for CONFIG_EVENT_ENTRY (i.e. config variables), the trailing newline
+ * character is considered part of the element.
+ */
+typedef int (*config_parser_event_fn_t)(enum config_event_t type,
+					size_t begin_offset, size_t end_offset,
+					void *event_fn_data);
+
 struct config_options {
 	unsigned int respect_includes : 1;
 	const char *commondir;
 	const char *git_dir;
+	config_parser_event_fn_t event_fn;
+	void *event_fn_data;
 };
 
 typedef int (*config_fn_t)(const char *, const char *, void *);
 extern int git_default_config(const char *, const char *, void *);
 extern int git_config_from_file(config_fn_t fn, const char *, void *);
+extern int git_config_from_file_with_options(config_fn_t fn, const char *,
+					     void *,
+					     const struct config_options *);
 extern int git_config_from_mem(config_fn_t fn, const enum config_origin_type,
 					const char *name, const char *buf, size_t len, void *data);
 extern int git_config_from_blob_oid(config_fn_t fn, const char *name,
@@ -59,6 +84,7 @@
 extern int git_config_string(const char **, const char *, const char *);
 extern int git_config_pathname(const char **, const char *, const char *);
 extern int git_config_expiry_date(timestamp_t *, const char *, const char *);
+extern int git_config_color(char *, const char *, const char *);
 extern int git_config_set_in_file_gently(const char *, const char *, const char *);
 extern void git_config_set_in_file(const char *, const char *, const char *);
 extern int git_config_set_gently(const char *, const char *);
diff --git a/config.mak.dev b/config.mak.dev
new file mode 100644
index 0000000..2d244ca
--- /dev/null
+++ b/config.mak.dev
@@ -0,0 +1,42 @@
+ifeq ($(filter no-error,$(DEVOPTS)),)
+CFLAGS += -Werror
+endif
+CFLAGS += -Wdeclaration-after-statement
+CFLAGS += -Wno-format-zero-length
+CFLAGS += -Wold-style-definition
+CFLAGS += -Woverflow
+CFLAGS += -Wpointer-arith
+CFLAGS += -Wstrict-prototypes
+CFLAGS += -Wunused
+CFLAGS += -Wvla
+
+ifndef COMPILER_FEATURES
+COMPILER_FEATURES := $(shell ./detect-compiler $(CC))
+endif
+
+ifneq ($(filter clang4,$(COMPILER_FEATURES)),)
+CFLAGS += -Wtautological-constant-out-of-range-compare
+endif
+
+ifneq ($(or $(filter gcc6,$(COMPILER_FEATURES)),$(filter clang4,$(COMPILER_FEATURES))),)
+CFLAGS += -Wextra
+# if a function is public, there should be a prototype and the right
+# header file should be included. If not, it should be static.
+CFLAGS += -Wmissing-prototypes
+ifeq ($(filter extra-all,$(DEVOPTS)),)
+# These are disabled because we have these all over the place.
+CFLAGS += -Wno-empty-body
+CFLAGS += -Wno-missing-field-initializers
+CFLAGS += -Wno-sign-compare
+CFLAGS += -Wno-unused-function
+CFLAGS += -Wno-unused-parameter
+endif
+endif
+
+# uninitialized warnings on gcc 4.9.2 in xdiff/xdiffi.c and config.c
+# not worth fixing since newer compilers correctly stop complaining
+ifneq ($(filter gcc4,$(COMPILER_FEATURES)),)
+ifeq ($(filter gcc5,$(COMPILER_FEATURES)),)
+CFLAGS += -Wno-uninitialized
+endif
+endif
diff --git a/config.mak.uname b/config.mak.uname
index 6a1d0de..684fc5b 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -37,6 +37,8 @@
 	HAVE_GETDELIM = YesPlease
 	SANE_TEXT_GREP=-a
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
+	BASIC_CFLAGS += -DHAVE_SYSINFO
+	PROCFS_EXECUTABLE_PATH = /proc/self/exe
 endif
 ifeq ($(uname_S),GNU/kFreeBSD)
 	HAVE_ALLOCA_H = YesPlease
@@ -111,6 +113,7 @@
 	BASIC_CFLAGS += -DPROTECT_HFS_DEFAULT=1
 	HAVE_BSD_SYSCTL = YesPlease
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
+	HAVE_NS_GET_EXECUTABLE_PATH = YesPlease
 endif
 ifeq ($(uname_S),SunOS)
 	NEEDS_SOCKET = YesPlease
@@ -205,6 +208,7 @@
 	HAVE_PATHS_H = YesPlease
 	GMTIME_UNRELIABLE_ERRORS = UnfortunatelyYes
 	HAVE_BSD_SYSCTL = YesPlease
+	HAVE_BSD_KERN_PROC_SYSCTL = YesPlease
 	PAGER_ENV = LESS=FRX LV=-c MORE=FRX
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
 endif
@@ -217,6 +221,8 @@
 	BASIC_LDFLAGS += -L/usr/local/lib
 	HAVE_PATHS_H = YesPlease
 	HAVE_BSD_SYSCTL = YesPlease
+	HAVE_BSD_KERN_PROC_SYSCTL = YesPlease
+	PROCFS_EXECUTABLE_PATH = /proc/curproc/file
 endif
 ifeq ($(uname_S),MirBSD)
 	NO_STRCASESTR = YesPlease
@@ -235,6 +241,8 @@
 	USE_ST_TIMESPEC = YesPlease
 	HAVE_PATHS_H = YesPlease
 	HAVE_BSD_SYSCTL = YesPlease
+	HAVE_BSD_KERN_PROC_SYSCTL = YesPlease
+	PROCFS_EXECUTABLE_PATH = /proc/curproc/exe
 endif
 ifeq ($(uname_S),AIX)
 	DEFAULT_PAGER = more
@@ -350,6 +358,7 @@
 	SNPRINTF_RETURNS_BOGUS = YesPlease
 	NO_SVN_TESTS = YesPlease
 	RUNTIME_PREFIX = YesPlease
+	HAVE_WPGMPTR = YesWeDo
 	NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
 	NO_NSEC = YesPlease
 	USE_WIN32_MMAP = YesPlease
@@ -499,6 +508,7 @@
 	NO_SVN_TESTS = YesPlease
 	NO_PERL_MAKEMAKER = YesPlease
 	RUNTIME_PREFIX = YesPlease
+	HAVE_WPGMPTR = YesWeDo
 	NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
 	NO_NSEC = YesPlease
 	USE_WIN32_MMAP = YesPlease
diff --git a/connect.c b/connect.c
index c3a014c..968e91b 100644
--- a/connect.c
+++ b/connect.c
@@ -12,9 +12,12 @@
 #include "sha1-array.h"
 #include "transport.h"
 #include "strbuf.h"
+#include "version.h"
 #include "protocol.h"
+#include "alias.h"
 
-static char *server_capabilities;
+static char *server_capabilities_v1;
+static struct argv_array server_capabilities_v2 = ARGV_ARRAY_INIT;
 static const char *parse_feature_value(const char *, const char *, int *);
 
 static int check_ref(const char *name, unsigned int flags)
@@ -46,8 +49,14 @@
 	return check_ref(ref->name, flags);
 }
 
-static void die_initial_contact(int unexpected)
+static NORETURN void die_initial_contact(int unexpected)
 {
+	/*
+	 * A hang-up after seeing some response from the other end
+	 * means that it is unexpected, as we know the other end is
+	 * willing to talk to us.  A hang-up before seeing any
+	 * response does not necessarily mean an ACL problem, though.
+	 */
 	if (unexpected)
 		die(_("The remote end hung up upon initial contact"));
 	else
@@ -56,6 +65,92 @@
 		      "and the repository exists."));
 }
 
+/* Checks if the server supports the capability 'c' */
+int server_supports_v2(const char *c, int die_on_error)
+{
+	int i;
+
+	for (i = 0; i < server_capabilities_v2.argc; i++) {
+		const char *out;
+		if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
+		    (!*out || *out == '='))
+			return 1;
+	}
+
+	if (die_on_error)
+		die("server doesn't support '%s'", c);
+
+	return 0;
+}
+
+int server_supports_feature(const char *c, const char *feature,
+			    int die_on_error)
+{
+	int i;
+
+	for (i = 0; i < server_capabilities_v2.argc; i++) {
+		const char *out;
+		if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
+		    (!*out || *(out++) == '=')) {
+			if (parse_feature_request(out, feature))
+				return 1;
+			else
+				break;
+		}
+	}
+
+	if (die_on_error)
+		die("server doesn't support feature '%s'", feature);
+
+	return 0;
+}
+
+static void process_capabilities_v2(struct packet_reader *reader)
+{
+	while (packet_reader_read(reader) == PACKET_READ_NORMAL)
+		argv_array_push(&server_capabilities_v2, reader->line);
+
+	if (reader->status != PACKET_READ_FLUSH)
+		die("expected flush after capabilities");
+}
+
+enum protocol_version discover_version(struct packet_reader *reader)
+{
+	enum protocol_version version = protocol_unknown_version;
+
+	/*
+	 * Peek the first line of the server's response to
+	 * determine the protocol version the server is speaking.
+	 */
+	switch (packet_reader_peek(reader)) {
+	case PACKET_READ_EOF:
+		die_initial_contact(0);
+	case PACKET_READ_FLUSH:
+	case PACKET_READ_DELIM:
+		version = protocol_v0;
+		break;
+	case PACKET_READ_NORMAL:
+		version = determine_protocol_version_client(reader->line);
+		break;
+	}
+
+	switch (version) {
+	case protocol_v2:
+		process_capabilities_v2(reader);
+		break;
+	case protocol_v1:
+		/* Read the peeked version line */
+		packet_reader_read(reader);
+		break;
+	case protocol_v0:
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
+	}
+
+	return version;
+}
+
 static void parse_one_symref_info(struct string_list *symref, const char *val, int len)
 {
 	char *sym, *target;
@@ -85,7 +180,7 @@
 static void annotate_refs_with_symref_info(struct ref *ref)
 {
 	struct string_list symref = STRING_LIST_INIT_DUP;
-	const char *feature_list = server_capabilities;
+	const char *feature_list = server_capabilities_v1;
 
 	while (feature_list) {
 		int len;
@@ -109,60 +204,21 @@
 	string_list_clear(&symref, 0);
 }
 
-/*
- * Read one line of a server's ref advertisement into packet_buffer.
- */
-static int read_remote_ref(int in, char **src_buf, size_t *src_len,
-			   int *responded)
+static void process_capabilities(const char *line, int *len)
 {
-	int len = packet_read(in, src_buf, src_len,
-			      packet_buffer, sizeof(packet_buffer),
-			      PACKET_READ_GENTLE_ON_EOF |
-			      PACKET_READ_CHOMP_NEWLINE);
-	const char *arg;
-	if (len < 0)
-		die_initial_contact(*responded);
-	if (len > 4 && skip_prefix(packet_buffer, "ERR ", &arg))
-		die("remote error: %s", arg);
-
-	*responded = 1;
-
-	return len;
-}
-
-#define EXPECTING_PROTOCOL_VERSION 0
-#define EXPECTING_FIRST_REF 1
-#define EXPECTING_REF 2
-#define EXPECTING_SHALLOW 3
-
-/* Returns 1 if packet_buffer is a protocol version pkt-line, 0 otherwise. */
-static int process_protocol_version(void)
-{
-	switch (determine_protocol_version_client(packet_buffer)) {
-	case protocol_v1:
-		return 1;
-	case protocol_v0:
-		return 0;
-	default:
-		die("server is speaking an unknown protocol");
-	}
-}
-
-static void process_capabilities(int *len)
-{
-	int nul_location = strlen(packet_buffer);
+	int nul_location = strlen(line);
 	if (nul_location == *len)
 		return;
-	server_capabilities = xstrdup(packet_buffer + nul_location + 1);
+	server_capabilities_v1 = xstrdup(line + nul_location + 1);
 	*len = nul_location;
 }
 
-static int process_dummy_ref(void)
+static int process_dummy_ref(const char *line)
 {
 	struct object_id oid;
 	const char *name;
 
-	if (parse_oid_hex(packet_buffer, &oid, &name))
+	if (parse_oid_hex(line, &oid, &name))
 		return 0;
 	if (*name != ' ')
 		return 0;
@@ -171,20 +227,20 @@
 	return !oidcmp(&null_oid, &oid) && !strcmp(name, "capabilities^{}");
 }
 
-static void check_no_capabilities(int len)
+static void check_no_capabilities(const char *line, int len)
 {
-	if (strlen(packet_buffer) != len)
+	if (strlen(line) != len)
 		warning("Ignoring capabilities after first line '%s'",
-			packet_buffer + strlen(packet_buffer));
+			line + strlen(line));
 }
 
-static int process_ref(int len, struct ref ***list, unsigned int flags,
-		       struct oid_array *extra_have)
+static int process_ref(const char *line, int len, struct ref ***list,
+		       unsigned int flags, struct oid_array *extra_have)
 {
 	struct object_id old_oid;
 	const char *name;
 
-	if (parse_oid_hex(packet_buffer, &old_oid, &name))
+	if (parse_oid_hex(line, &old_oid, &name))
 		return 0;
 	if (*name != ' ')
 		return 0;
@@ -200,16 +256,17 @@
 		**list = ref;
 		*list = &ref->next;
 	}
-	check_no_capabilities(len);
+	check_no_capabilities(line, len);
 	return 1;
 }
 
-static int process_shallow(int len, struct oid_array *shallow_points)
+static int process_shallow(const char *line, int len,
+			   struct oid_array *shallow_points)
 {
 	const char *arg;
 	struct object_id old_oid;
 
-	if (!skip_prefix(packet_buffer, "shallow ", &arg))
+	if (!skip_prefix(line, "shallow ", &arg))
 		return 0;
 
 	if (get_oid_hex(arg, &old_oid))
@@ -217,60 +274,68 @@
 	if (!shallow_points)
 		die("repository on the other end cannot be shallow");
 	oid_array_append(shallow_points, &old_oid);
-	check_no_capabilities(len);
+	check_no_capabilities(line, len);
 	return 1;
 }
 
+enum get_remote_heads_state {
+	EXPECTING_FIRST_REF = 0,
+	EXPECTING_REF,
+	EXPECTING_SHALLOW,
+	EXPECTING_DONE,
+};
+
 /*
  * Read all the refs from the other end
  */
-struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
+struct ref **get_remote_heads(struct packet_reader *reader,
 			      struct ref **list, unsigned int flags,
 			      struct oid_array *extra_have,
 			      struct oid_array *shallow_points)
 {
 	struct ref **orig_list = list;
-
-	/*
-	 * A hang-up after seeing some response from the other end
-	 * means that it is unexpected, as we know the other end is
-	 * willing to talk to us.  A hang-up before seeing any
-	 * response does not necessarily mean an ACL problem, though.
-	 */
-	int responded = 0;
-	int len;
-	int state = EXPECTING_PROTOCOL_VERSION;
+	int len = 0;
+	enum get_remote_heads_state state = EXPECTING_FIRST_REF;
+	const char *arg;
 
 	*list = NULL;
 
-	while ((len = read_remote_ref(in, &src_buf, &src_len, &responded))) {
+	while (state != EXPECTING_DONE) {
+		switch (packet_reader_read(reader)) {
+		case PACKET_READ_EOF:
+			die_initial_contact(1);
+		case PACKET_READ_NORMAL:
+			len = reader->pktlen;
+			if (len > 4 && skip_prefix(reader->line, "ERR ", &arg))
+				die("remote error: %s", arg);
+			break;
+		case PACKET_READ_FLUSH:
+			state = EXPECTING_DONE;
+			break;
+		case PACKET_READ_DELIM:
+			die("invalid packet");
+		}
+
 		switch (state) {
-		case EXPECTING_PROTOCOL_VERSION:
-			if (process_protocol_version()) {
-				state = EXPECTING_FIRST_REF;
-				break;
-			}
-			state = EXPECTING_FIRST_REF;
-			/* fallthrough */
 		case EXPECTING_FIRST_REF:
-			process_capabilities(&len);
-			if (process_dummy_ref()) {
+			process_capabilities(reader->line, &len);
+			if (process_dummy_ref(reader->line)) {
 				state = EXPECTING_SHALLOW;
 				break;
 			}
 			state = EXPECTING_REF;
 			/* fallthrough */
 		case EXPECTING_REF:
-			if (process_ref(len, &list, flags, extra_have))
+			if (process_ref(reader->line, len, &list, flags, extra_have))
 				break;
 			state = EXPECTING_SHALLOW;
 			/* fallthrough */
 		case EXPECTING_SHALLOW:
-			if (process_shallow(len, shallow_points))
+			if (process_shallow(reader->line, len, shallow_points))
 				break;
-			die("protocol error: unexpected '%s'", packet_buffer);
-		default:
-			die("unexpected state %d", state);
+			die("protocol error: unexpected '%s'", reader->line);
+		case EXPECTING_DONE:
+			break;
 		}
 	}
 
@@ -279,6 +344,112 @@
 	return list;
 }
 
+/* Returns 1 when a valid ref has been added to `list`, 0 otherwise */
+static int process_ref_v2(const char *line, struct ref ***list)
+{
+	int ret = 1;
+	int i = 0;
+	struct object_id old_oid;
+	struct ref *ref;
+	struct string_list line_sections = STRING_LIST_INIT_DUP;
+	const char *end;
+
+	/*
+	 * Ref lines have a number of fields which are space deliminated.  The
+	 * first field is the OID of the ref.  The second field is the ref
+	 * name.  Subsequent fields (symref-target and peeled) are optional and
+	 * don't have a particular order.
+	 */
+	if (string_list_split(&line_sections, line, ' ', -1) < 2) {
+		ret = 0;
+		goto out;
+	}
+
+	if (parse_oid_hex(line_sections.items[i++].string, &old_oid, &end) ||
+	    *end) {
+		ret = 0;
+		goto out;
+	}
+
+	ref = alloc_ref(line_sections.items[i++].string);
+
+	oidcpy(&ref->old_oid, &old_oid);
+	**list = ref;
+	*list = &ref->next;
+
+	for (; i < line_sections.nr; i++) {
+		const char *arg = line_sections.items[i].string;
+		if (skip_prefix(arg, "symref-target:", &arg))
+			ref->symref = xstrdup(arg);
+
+		if (skip_prefix(arg, "peeled:", &arg)) {
+			struct object_id peeled_oid;
+			char *peeled_name;
+			struct ref *peeled;
+			if (parse_oid_hex(arg, &peeled_oid, &end) || *end) {
+				ret = 0;
+				goto out;
+			}
+
+			peeled_name = xstrfmt("%s^{}", ref->name);
+			peeled = alloc_ref(peeled_name);
+
+			oidcpy(&peeled->old_oid, &peeled_oid);
+			**list = peeled;
+			*list = &peeled->next;
+
+			free(peeled_name);
+		}
+	}
+
+out:
+	string_list_clear(&line_sections, 0);
+	return ret;
+}
+
+struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
+			     struct ref **list, int for_push,
+			     const struct argv_array *ref_prefixes,
+			     const struct string_list *server_options)
+{
+	int i;
+	*list = NULL;
+
+	if (server_supports_v2("ls-refs", 1))
+		packet_write_fmt(fd_out, "command=ls-refs\n");
+
+	if (server_supports_v2("agent", 0))
+		packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());
+
+	if (server_options && server_options->nr &&
+	    server_supports_v2("server-option", 1))
+		for (i = 0; i < server_options->nr; i++)
+			packet_write_fmt(fd_out, "server-option=%s",
+					 server_options->items[i].string);
+
+	packet_delim(fd_out);
+	/* When pushing we don't want to request the peeled tags */
+	if (!for_push)
+		packet_write_fmt(fd_out, "peel\n");
+	packet_write_fmt(fd_out, "symrefs\n");
+	for (i = 0; ref_prefixes && i < ref_prefixes->argc; i++) {
+		packet_write_fmt(fd_out, "ref-prefix %s\n",
+				 ref_prefixes->argv[i]);
+	}
+	packet_flush(fd_out);
+
+	/* Process response from server */
+	while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
+		if (!process_ref_v2(reader->line, &list))
+			die("invalid ls-refs response: %s", reader->line);
+	}
+
+	if (reader->status != PACKET_READ_FLUSH)
+		die("expected flush after ref listing");
+
+	return list;
+}
+
 static const char *parse_feature_value(const char *feature_list, const char *feature, int *lenp)
 {
 	int len;
@@ -323,7 +494,7 @@
 
 const char *server_feature_value(const char *feature, int *len)
 {
-	return parse_feature_value(server_capabilities, feature, len);
+	return parse_feature_value(server_capabilities_v1, feature, len);
 }
 
 int server_supports(const char *feature)
@@ -872,6 +1043,7 @@
  */
 static struct child_process *git_connect_git(int fd[2], char *hostandport,
 					     const char *path, const char *prog,
+					     enum protocol_version version,
 					     int flags)
 {
 	struct child_process *conn;
@@ -910,10 +1082,10 @@
 		    target_host, 0);
 
 	/* If using a new version put that stuff here after a second null byte */
-	if (get_protocol_version_config() > 0) {
+	if (version > 0) {
 		strbuf_addch(&request, '\0');
 		strbuf_addf(&request, "version=%d%c",
-			    get_protocol_version_config(), '\0');
+			    version, '\0');
 	}
 
 	packet_write(fd[1], request.buf, request.len);
@@ -929,14 +1101,14 @@
  */
 static void push_ssh_options(struct argv_array *args, struct argv_array *env,
 			     enum ssh_variant variant, const char *port,
-			     int flags)
+			     enum protocol_version version, int flags)
 {
 	if (variant == VARIANT_SSH &&
-	    get_protocol_version_config() > 0) {
+	    version > 0) {
 		argv_array_push(args, "-o");
 		argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
 		argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
-				 get_protocol_version_config());
+				 version);
 	}
 
 	if (flags & CONNECT_IPV4) {
@@ -989,7 +1161,8 @@
 
 /* Prepare a child_process for use by Git's SSH-tunneled transport. */
 static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
-			  const char *port, int flags)
+			  const char *port, enum protocol_version version,
+			  int flags)
 {
 	const char *ssh;
 	enum ssh_variant variant;
@@ -1023,14 +1196,14 @@
 		argv_array_push(&detect.args, ssh);
 		argv_array_push(&detect.args, "-G");
 		push_ssh_options(&detect.args, &detect.env_array,
-				 VARIANT_SSH, port, flags);
+				 VARIANT_SSH, port, version, flags);
 		argv_array_push(&detect.args, ssh_host);
 
 		variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
 	}
 
 	argv_array_push(&conn->args, ssh);
-	push_ssh_options(&conn->args, &conn->env_array, variant, port, flags);
+	push_ssh_options(&conn->args, &conn->env_array, variant, port, version, flags);
 	argv_array_push(&conn->args, ssh_host);
 }
 
@@ -1051,6 +1224,15 @@
 	char *hostandport, *path;
 	struct child_process *conn;
 	enum protocol protocol;
+	enum protocol_version version = get_protocol_version_config();
+
+	/*
+	 * NEEDSWORK: If we are trying to use protocol v2 and we are planning
+	 * to perform a push, then fallback to v0 since the client doesn't know
+	 * how to push yet using v2.
+	 */
+	if (version == protocol_v2 && !strcmp("git-receive-pack", prog))
+		version = protocol_v0;
 
 	/* Without this we cannot rely on waitpid() to tell
 	 * what happened to our children.
@@ -1065,7 +1247,7 @@
 		printf("Diag: path=%s\n", path ? path : "NULL");
 		conn = NULL;
 	} else if (protocol == PROTO_GIT) {
-		conn = git_connect_git(fd, hostandport, path, prog, flags);
+		conn = git_connect_git(fd, hostandport, path, prog, version, flags);
 	} else {
 		struct strbuf cmd = STRBUF_INIT;
 		const char *const *var;
@@ -1108,12 +1290,12 @@
 				strbuf_release(&cmd);
 				return NULL;
 			}
-			fill_ssh_args(conn, ssh_host, port, flags);
+			fill_ssh_args(conn, ssh_host, port, version, flags);
 		} else {
 			transport_check_allowed("file");
-			if (get_protocol_version_config() > 0) {
+			if (version > 0) {
 				argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
-						 get_protocol_version_config());
+						 version);
 			}
 		}
 		argv_array_push(&conn->args, cmd.buf);
diff --git a/connect.h b/connect.h
index 01f14cd..0e69c67 100644
--- a/connect.h
+++ b/connect.h
@@ -13,4 +13,11 @@
 extern const char *server_feature_value(const char *feature, int *len_ret);
 extern int url_is_local_not_ssh(const char *url);
 
+struct packet_reader;
+extern enum protocol_version discover_version(struct packet_reader *reader);
+
+extern int server_supports_v2(const char *c, int die_on_error);
+extern int server_supports_feature(const char *c, const char *feature,
+				   int die_on_error);
+
 #endif
diff --git a/contrib/coccinelle/commit.cocci b/contrib/coccinelle/commit.cocci
new file mode 100644
index 0000000..a7e9215
--- /dev/null
+++ b/contrib/coccinelle/commit.cocci
@@ -0,0 +1,28 @@
+@@
+expression c;
+@@
+- &c->maybe_tree->object.oid
++ get_commit_tree_oid(c)
+
+@@
+expression c;
+@@
+- c->maybe_tree->object.oid.hash
++ get_commit_tree_oid(c)->hash
+
+// These excluded functions must access c->maybe_tree direcly.
+@@
+identifier f !~ "^(get_commit_tree|get_commit_tree_in_graph|load_tree_for_commit)$";
+expression c;
+@@
+  f(...) {...
+- c->maybe_tree
++ get_commit_tree(c)
+  ...}
+
+@@
+expression c;
+expression s;
+@@
+- get_commit_tree(c) = s
++ c->maybe_tree = s
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 7fe2e21..12814e9 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -94,6 +94,70 @@
 		${__git_dir:+--git-dir="$__git_dir"} "$@" 2>/dev/null
 }
 
+# Removes backslash escaping, single quotes and double quotes from a word,
+# stores the result in the variable $dequoted_word.
+# 1: The word to dequote.
+__git_dequote ()
+{
+	local rest="$1" len ch
+
+	dequoted_word=""
+
+	while test -n "$rest"; do
+		len=${#dequoted_word}
+		dequoted_word="$dequoted_word${rest%%[\\\'\"]*}"
+		rest="${rest:$((${#dequoted_word}-$len))}"
+
+		case "${rest:0:1}" in
+		\\)
+			ch="${rest:1:1}"
+			case "$ch" in
+			$'\n')
+				;;
+			*)
+				dequoted_word="$dequoted_word$ch"
+				;;
+			esac
+			rest="${rest:2}"
+			;;
+		\')
+			rest="${rest:1}"
+			len=${#dequoted_word}
+			dequoted_word="$dequoted_word${rest%%\'*}"
+			rest="${rest:$((${#dequoted_word}-$len+1))}"
+			;;
+		\")
+			rest="${rest:1}"
+			while test -n "$rest" ; do
+				len=${#dequoted_word}
+				dequoted_word="$dequoted_word${rest%%[\\\"]*}"
+				rest="${rest:$((${#dequoted_word}-$len))}"
+				case "${rest:0:1}" in
+				\\)
+					ch="${rest:1:1}"
+					case "$ch" in
+					\"|\\|\$|\`)
+						dequoted_word="$dequoted_word$ch"
+						;;
+					$'\n')
+						;;
+					*)
+						dequoted_word="$dequoted_word\\$ch"
+						;;
+					esac
+					rest="${rest:2}"
+					;;
+				\")
+					rest="${rest:1}"
+					break
+					;;
+				esac
+			done
+			;;
+		esac
+	done
+}
+
 # The following function is based on code from:
 #
 #   bash_completion - programmable completion functions for bash 3.2+
@@ -284,7 +348,11 @@
 
 # Clear the variables caching builtins' options when (re-)sourcing
 # the completion script.
-unset $(set |sed -ne 's/^\(__gitcomp_builtin_[a-zA-Z0-9_][a-zA-Z0-9_]*\)=.*/\1/p') 2>/dev/null
+if [[ -n ${ZSH_VERSION-} ]]; then
+	unset $(set |sed -ne 's/^\(__gitcomp_builtin_[a-zA-Z0-9_][a-zA-Z0-9_]*\)=.*/\1/p') 2>/dev/null
+else
+	unset $(compgen -v __gitcomp_builtin_)
+fi
 
 # This function is equivalent to
 #
@@ -342,6 +410,24 @@
 	__gitcomp_nl_append "$@"
 }
 
+# Fills the COMPREPLY array with prefiltered paths without any additional
+# processing.
+# Callers must take care of providing only paths that match the current path
+# to be completed and adding any prefix path components, if necessary.
+# 1: List of newline-separated matching paths, complete with all prefix
+#    path componens.
+__gitcomp_file_direct ()
+{
+	local IFS=$'\n'
+
+	COMPREPLY=($1)
+
+	# use a hack to enable file mode in bash < 4
+	compopt -o filenames +o nospace 2>/dev/null ||
+	compgen -f /non-existing-dir/ >/dev/null ||
+	true
+}
+
 # Generates completion reply with compgen from newline-separated possible
 # completion filenames.
 # It accepts 1 to 3 arguments:
@@ -361,7 +447,8 @@
 
 	# use a hack to enable file mode in bash < 4
 	compopt -o filenames +o nospace 2>/dev/null ||
-	compgen -f /non-existing-dir/ > /dev/null
+	compgen -f /non-existing-dir/ >/dev/null ||
+	true
 }
 
 # Execute 'git ls-files', unless the --committable option is specified, in
@@ -371,10 +458,12 @@
 __git_ls_files_helper ()
 {
 	if [ "$2" == "--committable" ]; then
-		__git -C "$1" diff-index --name-only --relative HEAD
+		__git -C "$1" -c core.quotePath=false diff-index \
+			--name-only --relative HEAD -- "${3//\\/\\\\}*"
 	else
 		# NOTE: $2 is not quoted in order to support multiple options
-		__git -C "$1" ls-files --exclude-standard $2
+		__git -C "$1" -c core.quotePath=false ls-files \
+			--exclude-standard $2 -- "${3//\\/\\\\}*"
 	fi
 }
 
@@ -385,12 +474,103 @@
 #    If provided, only files within the specified directory are listed.
 #    Sub directories are never recursed.  Path must have a trailing
 #    slash.
+# 3: List only paths matching this path component (optional).
 __git_index_files ()
 {
-	local root="${2-.}" file
+	local root="$2" match="$3"
 
-	__git_ls_files_helper "$root" "$1" |
-	cut -f1 -d/ | sort | uniq
+	__git_ls_files_helper "$root" "$1" "$match" |
+	awk -F / -v pfx="${2//\\/\\\\}" '{
+		paths[$1] = 1
+	}
+	END {
+		for (p in paths) {
+			if (substr(p, 1, 1) != "\"") {
+				# No special characters, easy!
+				print pfx p
+				continue
+			}
+
+			# The path is quoted.
+			p = dequote(p)
+			if (p == "")
+				continue
+
+			# Even when a directory name itself does not contain
+			# any special characters, it will still be quoted if
+			# any of its (stripped) trailing path components do.
+			# Because of this we may have seen the same direcory
+			# both quoted and unquoted.
+			if (p in paths)
+				# We have seen the same directory unquoted,
+				# skip it.
+				continue
+			else
+				print pfx p
+		}
+	}
+	function dequote(p,    bs_idx, out, esc, esc_idx, dec) {
+		# Skip opening double quote.
+		p = substr(p, 2)
+
+		# Interpret backslash escape sequences.
+		while ((bs_idx = index(p, "\\")) != 0) {
+			out = out substr(p, 1, bs_idx - 1)
+			esc = substr(p, bs_idx + 1, 1)
+			p = substr(p, bs_idx + 2)
+
+			if ((esc_idx = index("abtvfr\"\\", esc)) != 0) {
+				# C-style one-character escape sequence.
+				out = out substr("\a\b\t\v\f\r\"\\",
+						 esc_idx, 1)
+			} else if (esc == "n") {
+				# Uh-oh, a newline character.
+				# We cant reliably put a pathname
+				# containing a newline into COMPREPLY,
+				# and the newline would create a mess.
+				# Skip this path.
+				return ""
+			} else {
+				# Must be a \nnn octal value, then.
+				dec = esc             * 64 + \
+				      substr(p, 1, 1) * 8  + \
+				      substr(p, 2, 1)
+				out = out sprintf("%c", dec)
+				p = substr(p, 3)
+			}
+		}
+		# Drop closing double quote, if there is one.
+		# (There isnt any if this is a directory, as it was
+		# already stripped with the trailing path components.)
+		if (substr(p, length(p), 1) == "\"")
+			out = out substr(p, 1, length(p) - 1)
+		else
+			out = out p
+
+		return out
+	}'
+}
+
+# __git_complete_index_file requires 1 argument:
+# 1: the options to pass to ls-file
+#
+# The exception is --committable, which finds the files appropriate commit.
+__git_complete_index_file ()
+{
+	local dequoted_word pfx="" cur_
+
+	__git_dequote "$cur"
+
+	case "$dequoted_word" in
+	?*/*)
+		pfx="${dequoted_word%/*}/"
+		cur_="${dequoted_word##*/}"
+		;;
+	*)
+		cur_="$dequoted_word"
+	esac
+
+	__gitcomp_file_direct "$(__git_index_files "$1" "$pfx" "$cur_")"
 }
 
 # Lists branches from the local repository.
@@ -709,26 +889,6 @@
 	esac
 }
 
-
-# __git_complete_index_file requires 1 argument:
-# 1: the options to pass to ls-file
-#
-# The exception is --committable, which finds the files appropriate commit.
-__git_complete_index_file ()
-{
-	local pfx="" cur_="$cur"
-
-	case "$cur_" in
-	?*/*)
-		pfx="${cur_%/*}"
-		cur_="${cur_##*/}"
-		pfx="${pfx}/"
-		;;
-	esac
-
-	__gitcomp_file "$(__git_index_files "$1" ${pfx:+"$pfx"})" "$pfx" "$cur_"
-}
-
 __git_complete_file ()
 {
 	__git_complete_revlist_file
@@ -829,126 +989,11 @@
 	return 1
 }
 
-__git_commands () {
-	if test -n "${GIT_TESTING_COMMAND_COMPLETION:-}"
-	then
-		printf "%s" "${GIT_TESTING_COMMAND_COMPLETION}"
-	else
-		git help -a|egrep '^  [a-zA-Z0-9]'
-	fi
-}
-
-__git_list_all_commands ()
-{
-	local i IFS=" "$'\n'
-	for i in $(__git_commands)
-	do
-		case $i in
-		*--*)             : helper pattern;;
-		*) echo $i;;
-		esac
-	done
-}
-
 __git_all_commands=
 __git_compute_all_commands ()
 {
 	test -n "$__git_all_commands" ||
-	__git_all_commands=$(__git_list_all_commands)
-}
-
-__git_list_porcelain_commands ()
-{
-	local i IFS=" "$'\n'
-	__git_compute_all_commands
-	for i in $__git_all_commands
-	do
-		case $i in
-		*--*)             : helper pattern;;
-		applymbox)        : ask gittus;;
-		applypatch)       : ask gittus;;
-		archimport)       : import;;
-		cat-file)         : plumbing;;
-		check-attr)       : plumbing;;
-		check-ignore)     : plumbing;;
-		check-mailmap)    : plumbing;;
-		check-ref-format) : plumbing;;
-		checkout-index)   : plumbing;;
-		column)           : internal helper;;
-		commit-tree)      : plumbing;;
-		count-objects)    : infrequent;;
-		credential)       : credentials;;
-		credential-*)     : credentials helper;;
-		cvsexportcommit)  : export;;
-		cvsimport)        : import;;
-		cvsserver)        : daemon;;
-		daemon)           : daemon;;
-		diff-files)       : plumbing;;
-		diff-index)       : plumbing;;
-		diff-tree)        : plumbing;;
-		fast-import)      : import;;
-		fast-export)      : export;;
-		fsck-objects)     : plumbing;;
-		fetch-pack)       : plumbing;;
-		fmt-merge-msg)    : plumbing;;
-		for-each-ref)     : plumbing;;
-		hash-object)      : plumbing;;
-		http-*)           : transport;;
-		index-pack)       : plumbing;;
-		init-db)          : deprecated;;
-		local-fetch)      : plumbing;;
-		ls-files)         : plumbing;;
-		ls-remote)        : plumbing;;
-		ls-tree)          : plumbing;;
-		mailinfo)         : plumbing;;
-		mailsplit)        : plumbing;;
-		merge-*)          : plumbing;;
-		mktree)           : plumbing;;
-		mktag)            : plumbing;;
-		pack-objects)     : plumbing;;
-		pack-redundant)   : plumbing;;
-		pack-refs)        : plumbing;;
-		parse-remote)     : plumbing;;
-		patch-id)         : plumbing;;
-		prune)            : plumbing;;
-		prune-packed)     : plumbing;;
-		quiltimport)      : import;;
-		read-tree)        : plumbing;;
-		receive-pack)     : plumbing;;
-		remote-*)         : transport;;
-		rerere)           : plumbing;;
-		rev-list)         : plumbing;;
-		rev-parse)        : plumbing;;
-		runstatus)        : plumbing;;
-		sh-setup)         : internal;;
-		shell)            : daemon;;
-		show-ref)         : plumbing;;
-		send-pack)        : plumbing;;
-		show-index)       : plumbing;;
-		ssh-*)            : transport;;
-		stripspace)       : plumbing;;
-		symbolic-ref)     : plumbing;;
-		unpack-file)      : plumbing;;
-		unpack-objects)   : plumbing;;
-		update-index)     : plumbing;;
-		update-ref)       : plumbing;;
-		update-server-info) : daemon;;
-		upload-archive)   : plumbing;;
-		upload-pack)      : plumbing;;
-		write-tree)       : plumbing;;
-		var)              : infrequent;;
-		verify-pack)      : infrequent;;
-		verify-tag)       : plumbing;;
-		*) echo $i;;
-		esac
-	done
-}
-
-__git_porcelain_commands=
-__git_compute_porcelain_commands ()
-{
-	test -n "$__git_porcelain_commands" ||
-	__git_porcelain_commands=$(__git_list_porcelain_commands)
+	__git_all_commands=$(git --list-cmds=main,others,alias,nohelpers)
 }
 
 # Lists all set config variables starting with the given section prefix,
@@ -966,11 +1011,6 @@
 	__git_get_config_variables "pretty"
 }
 
-__git_aliases ()
-{
-	__git_get_config_variables "alias"
-}
-
 # __git_aliased_command requires 1 argument
 __git_aliased_command ()
 {
@@ -1578,13 +1618,12 @@
 		return
 		;;
 	esac
-	__git_compute_all_commands
-	__gitcomp "$__git_all_commands $(__git_aliases)
-		attributes cli core-tutorial cvs-migration
-		diffcore everyday gitk glossary hooks ignore modules
-		namespaces repository-layout revisions tutorial tutorial-2
-		workflows
-		"
+	if test -n "$GIT_TESTING_ALL_COMMAND_LIST"
+	then
+		__gitcomp "$GIT_TESTING_ALL_COMMAND_LIST $(git --list-cmds=alias,list-guide) gitk"
+	else
+		__gitcomp "$(git --list-cmds=main,nohelpers,alias,list-guide) gitk"
+	fi
 }
 
 _git_init ()
@@ -2172,7 +2211,7 @@
 		__gitcomp "$__git_log_date_formats"
 		return
 		;;
-	sendemail.aliasesfiletype)
+	sendemail.aliasfiletype)
 		__gitcomp "mutt mailrc pine elm gnus"
 		return
 		;;
@@ -2345,6 +2384,7 @@
 		core.bigFileThreshold
 		core.checkStat
 		core.commentChar
+		core.commitGraph
 		core.compression
 		core.createObject
 		core.deltaBaseCacheLimit
@@ -2769,13 +2809,21 @@
 _git_stash ()
 {
 	local save_opts='--all --keep-index --no-keep-index --quiet --patch --include-untracked'
-	local subcommands='push save list show apply clear drop pop create branch'
-	local subcommand="$(__git_find_on_cmdline "$subcommands")"
+	local subcommands='push list show apply clear drop pop create branch'
+	local subcommand="$(__git_find_on_cmdline "$subcommands save")"
+	if [ -n "$(__git_find_on_cmdline "-p")" ]; then
+		subcommand="push"
+	fi
 	if [ -z "$subcommand" ]; then
 		case "$cur" in
 		--*)
 			__gitcomp "$save_opts"
 			;;
+		sa*)
+			if [ -z "$(__git_find_on_cmdline "$save_opts")" ]; then
+				__gitcomp "save"
+			fi
+			;;
 		*)
 			if [ -z "$(__git_find_on_cmdline "$save_opts")" ]; then
 				__gitcomp "$subcommands"
@@ -3044,7 +3092,7 @@
 __git_cmds_with_parseopt_helper=
 __git_support_parseopt_helper () {
 	test -n "$__git_cmds_with_parseopt_helper" ||
-		__git_cmds_with_parseopt_helper="$(__git --list-parseopt-builtins)"
+		__git_cmds_with_parseopt_helper="$(__git --list-cmds=parseopt)"
 
 	case " $__git_cmds_with_parseopt_helper " in
 	*" $1 "*)
@@ -3059,10 +3107,17 @@
 __git_complete_command () {
 	local command="$1"
 	local completion_func="_git_${command//-/_}"
-	if declare -f $completion_func >/dev/null 2>/dev/null; then
+	if ! declare -f $completion_func >/dev/null 2>/dev/null &&
+		declare -f _completion_loader >/dev/null 2>/dev/null
+	then
+		_completion_loader "git-$command"
+	fi
+	if declare -f $completion_func >/dev/null 2>/dev/null
+	then
 		$completion_func
 		return 0
-	elif __git_support_parseopt_helper "$command"; then
+	elif __git_support_parseopt_helper "$command"
+	then
 		__git_complete_common "$command"
 		return 0
 	else
@@ -3123,8 +3178,14 @@
 			--help
 			"
 			;;
-		*)     __git_compute_porcelain_commands
-		       __gitcomp "$__git_porcelain_commands $(__git_aliases)" ;;
+		*)
+			if test -n "$GIT_TESTING_PORCELAIN_COMMAND_LIST"
+			then
+				__gitcomp "$GIT_TESTING_PORCELAIN_COMMAND_LIST"
+			else
+				__gitcomp "$(git --list-cmds=list-mainporcelain,others,nohelpers,alias,list-complete,config)"
+			fi
+			;;
 		esac
 		return
 	fi
@@ -3211,6 +3272,15 @@
 		compadd -Q -S "${4- }" -p "${2-}" -- ${=1} && _ret=0
 	}
 
+	__gitcomp_file_direct ()
+	{
+		emulate -L zsh
+
+		local IFS=$'\n'
+		compset -P '*[=:]'
+		compadd -Q -f -- ${=1} && _ret=0
+	}
+
 	__gitcomp_file ()
 	{
 		emulate -L zsh
diff --git a/contrib/completion/git-completion.zsh b/contrib/completion/git-completion.zsh
index c3521fb..53cb0f9 100644
--- a/contrib/completion/git-completion.zsh
+++ b/contrib/completion/git-completion.zsh
@@ -93,6 +93,15 @@
 	compadd -Q -S "${4- }" -p "${2-}" -- ${=1} && _ret=0
 }
 
+__gitcomp_file_direct ()
+{
+	emulate -L zsh
+
+	local IFS=$'\n'
+	compset -P '*[=:]'
+	compadd -Q -f -- ${=1} && _ret=0
+}
+
 __gitcomp_file ()
 {
 	emulate -L zsh
diff --git a/contrib/convert-grafts-to-replace-refs.sh b/contrib/convert-grafts-to-replace-refs.sh
deleted file mode 100755
index 0cbc917..0000000
--- a/contrib/convert-grafts-to-replace-refs.sh
+++ /dev/null
@@ -1,28 +0,0 @@
-#!/bin/sh
-
-# You should execute this script in the repository where you
-# want to convert grafts to replace refs.
-
-GRAFTS_FILE="${GIT_DIR:-.git}/info/grafts"
-
-. $(git --exec-path)/git-sh-setup
-
-test -f "$GRAFTS_FILE" || die "Could not find graft file: '$GRAFTS_FILE'"
-
-grep '^[^# ]' "$GRAFTS_FILE" |
-while read definition
-do
-	if test -n "$definition"
-	then
-		echo "Converting: $definition"
-		git replace --graft $definition ||
-			die "Conversion failed for: $definition"
-	fi
-done
-
-mv "$GRAFTS_FILE" "$GRAFTS_FILE.bak" ||
-	die "Could not rename '$GRAFTS_FILE' to '$GRAFTS_FILE.bak'"
-
-echo "Success!"
-echo "All the grafts in '$GRAFTS_FILE' have been converted to replace refs!"
-echo "The grafts file '$GRAFTS_FILE' has been renamed: '$GRAFTS_FILE.bak'"
diff --git a/contrib/credential/netrc/Makefile b/contrib/credential/netrc/Makefile
index 51b7613..0ffa407 100644
--- a/contrib/credential/netrc/Makefile
+++ b/contrib/credential/netrc/Makefile
@@ -1,5 +1,5 @@
 test:
-	./test.pl
+	./t-git-credential-netrc.sh
 
 testverbose:
-	./test.pl -d -v
+	./t-git-credential-netrc.sh -d -v
diff --git a/contrib/credential/netrc/git-credential-netrc b/contrib/credential/netrc/git-credential-netrc
index 1571a7b..0b9a941 100755
--- a/contrib/credential/netrc/git-credential-netrc
+++ b/contrib/credential/netrc/git-credential-netrc
@@ -2,11 +2,13 @@
 
 use strict;
 use warnings;
+use autodie;
 
 use Getopt::Long;
 use File::Basename;
+use Git;
 
-my $VERSION = "0.1";
+my $VERSION = "0.2";
 
 my %options = (
 	       help => 0,
@@ -54,6 +56,7 @@
            "insecure|k",
            "verbose|v",
            "file|f=s@",
+           'gpg|g:s',
           );
 
 if ($options{help}) {
@@ -62,27 +65,31 @@
 
 	print <<EOHIPPUS;
 
-$0 [-f AUTHFILE1] [-f AUTHFILEN] [-d] [-v] [-k] get
+$0 [(-f <authfile>)...] [-g <program>] [-d] [-v] [-k] get
 
 Version $VERSION by tzz\@lifelogs.com.  License: BSD.
 
 Options:
 
-  -f|--file AUTHFILE : specify netrc-style files.  Files with the .gpg extension
-                       will be decrypted by GPG before parsing.  Multiple -f
-                       arguments are OK.  They are processed in order, and the
-                       first matching entry found is returned via the credential
-                       helper protocol (see below).
+  -f|--file <authfile>: specify netrc-style files.  Files with the .gpg
+                        extension will be decrypted by GPG before parsing.
+                        Multiple -f arguments are OK.  They are processed in
+                        order, and the first matching entry found is returned
+                        via the credential helper protocol (see below).
 
-                       When no -f option is given, .authinfo.gpg, .netrc.gpg,
-		       .authinfo, and .netrc files in your home directory are used
-		       in this order.
+                        When no -f option is given, .authinfo.gpg, .netrc.gpg,
+                        .authinfo, and .netrc files in your home directory are
+                        used in this order.
 
-  -k|--insecure      : ignore bad file ownership or permissions
+  -g|--gpg <program>  : specify the program for GPG. By default, this is the
+                        value of gpg.program in the git repository or global
+                        option or gpg.
 
-  -d|--debug         : turn on debugging (developer info)
+  -k|--insecure       : ignore bad file ownership or permissions
 
-  -v|--verbose       : be more verbose (show files and information found)
+  -d|--debug          : turn on debugging (developer info)
+
+  -v|--verbose        : be more verbose (show files and information found)
 
 To enable this credential helper:
 
@@ -99,8 +106,9 @@
 
   git config credential.helper '$shortname -f AUTHFILE -v'
 
-Only "get" mode is supported by this credential helper.  It opens every AUTHFILE
-and looks for the first entry that matches the requested search criteria:
+Only "get" mode is supported by this credential helper.  It opens every
+<authfile> and looks for the first entry that matches the requested search
+criteria:
 
  'port|protocol':
    The protocol that will be used (e.g., https). (protocol=X)
@@ -120,7 +128,7 @@
 protocol=https
 username=tzz
 
-this credential helper will look for the first entry in every AUTHFILE that
+this credential helper will look for the first entry in every <authfile> that
 matches
 
 machine github.com port https login tzz
@@ -137,8 +145,8 @@
 back to "protocol".  Any redundant entry tokens (part of the original query) are
 skipped.
 
-Again, note that only the first matching entry from all the AUTHFILEs, processed
-in the sequence given on the command line, is used.
+Again, note that only the first matching entry from all the <authfile>s,
+processed in the sequence given on the command line, is used.
 
 Netrc/authinfo tokens can be quoted as 'STRING' or "STRING".
 
@@ -152,7 +160,7 @@
 my $mode = shift @ARGV;
 
 # Credentials must get a parameter, so die if it's missing.
-die "Syntax: $0 [-f AUTHFILE1] [-f AUTHFILEN] [-d] get" unless defined $mode;
+die "Syntax: $0 [(-f <authfile>)...] [-d] get" unless defined $mode;
 
 # Only support 'get' mode; with any other unsupported ones we just exit.
 exit 0 unless $mode eq 'get';
@@ -172,6 +180,8 @@
 	$files = $options{file} = [ map { glob $_ } @candidates ];
 }
 
+load_config(\%options);
+
 my $query = read_credential_data_from_stdin();
 
 FILE:
@@ -233,7 +243,7 @@
 
 	my $io;
 	if ($gpgmode) {
-		my @cmd = (qw(gpg --decrypt), $file);
+		my @cmd = ($options{'gpg'}, qw(--decrypt), $file);
 		log_verbose("Using GPG to open $file: [@cmd]");
 		open $io, "-|", @cmd;
 	} else {
@@ -410,6 +420,14 @@
 		printf "%s=%s\n", $git_token, $entry->{$git_token};
 	}
 }
+sub load_config {
+	# load settings from git config
+	my $options = shift;
+	# set from command argument, gpg.program option, or default to gpg
+	$options->{'gpg'} //= Git->repository()->config('gpg.program')
+	                  // 'gpg';
+	log_verbose("using $options{'gpg'} for GPG operations");
+}
 sub log_verbose {
 	return unless $options{verbose};
 	printf STDERR @_;
diff --git a/contrib/credential/netrc/t-git-credential-netrc.sh b/contrib/credential/netrc/t-git-credential-netrc.sh
new file mode 100755
index 0000000..58191a6
--- /dev/null
+++ b/contrib/credential/netrc/t-git-credential-netrc.sh
@@ -0,0 +1,31 @@
+#!/bin/sh
+(
+	cd ../../../t
+	test_description='git-credential-netrc'
+	. ./test-lib.sh
+
+	if ! test_have_prereq PERL; then
+		skip_all='skipping perl interface tests, perl not available'
+		test_done
+	fi
+
+	perl -MTest::More -e 0 2>/dev/null || {
+		skip_all="Perl Test::More unavailable, skipping test"
+		test_done
+	}
+
+	# set up test repository
+
+	test_expect_success \
+    'set up test repository' \
+    'git config --add gpg.program test.git-config-gpg'
+
+	# The external test will outputs its own plan
+	test_external_has_tap=1
+
+	test_external \
+    'git-credential-netrc' \
+    perl "$TEST_DIRECTORY"/../contrib/credential/netrc/test.pl
+
+	test_done
+)
diff --git a/contrib/credential/netrc/test.command-option-gpg b/contrib/credential/netrc/test.command-option-gpg
new file mode 100755
index 0000000..d8f1285
--- /dev/null
+++ b/contrib/credential/netrc/test.command-option-gpg
@@ -0,0 +1,2 @@
+#!/bin/sh
+echo machine command-option-gpg login username password password
diff --git a/contrib/credential/netrc/test.git-config-gpg b/contrib/credential/netrc/test.git-config-gpg
new file mode 100755
index 0000000..65cf594
--- /dev/null
+++ b/contrib/credential/netrc/test.git-config-gpg
@@ -0,0 +1,2 @@
+#!/bin/sh
+echo machine git-config-gpg login username password password
diff --git a/contrib/credential/netrc/test.netrc.gpg b/contrib/credential/netrc/test.netrc.gpg
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/contrib/credential/netrc/test.netrc.gpg
diff --git a/contrib/credential/netrc/test.pl b/contrib/credential/netrc/test.pl
index 169b646..1e10010 100755
--- a/contrib/credential/netrc/test.pl
+++ b/contrib/credential/netrc/test.pl
@@ -1,83 +1,115 @@
 #!/usr/bin/perl
+use lib (split(/:/, $ENV{GITPERLLIB}));
 
 use warnings;
 use strict;
-use Test;
+use Test::More qw(no_plan);
+use File::Basename;
+use File::Spec::Functions qw(:DEFAULT rel2abs);
 use IPC::Open2;
 
-BEGIN { plan tests => 15 }
+BEGIN {
+	# t-git-credential-netrc.sh kicks off our testing, so we have to go
+	# from there.
+	Test::More->builder->current_test(1);
+	Test::More->builder->no_ending(1);
+}
 
 my @global_credential_args = @ARGV;
-my $netrc = './test.netrc';
-print "# Testing insecure file, nothing should be found\n";
+my $scriptDir = dirname rel2abs $0;
+my ($netrc, $netrcGpg, $gcNetrc) = map { catfile $scriptDir, $_; }
+                                       qw(test.netrc
+                                          test.netrc.gpg
+                                          git-credential-netrc);
+local $ENV{PATH} = join ':'
+                      , $scriptDir
+                      , $ENV{PATH}
+                      ? $ENV{PATH}
+                      : ();
+
+diag "Testing insecure file, nothing should be found\n";
 chmod 0644, $netrc;
 my $cred = run_credential(['-f', $netrc, 'get'],
 			  { host => 'github.com' });
 
-ok(scalar keys %$cred, 0, "Got 0 keys from insecure file");
+ok(scalar keys %$cred == 0, "Got 0 keys from insecure file");
 
-print "# Testing missing file, nothing should be found\n";
+diag "Testing missing file, nothing should be found\n";
 chmod 0644, $netrc;
 $cred = run_credential(['-f', '///nosuchfile///', 'get'],
 		       { host => 'github.com' });
 
-ok(scalar keys %$cred, 0, "Got 0 keys from missing file");
+ok(scalar keys %$cred == 0, "Got 0 keys from missing file");
 
 chmod 0600, $netrc;
 
-print "# Testing with invalid data\n";
+diag "Testing with invalid data\n";
 $cred = run_credential(['-f', $netrc, 'get'],
 		       "bad data");
-ok(scalar keys %$cred, 4, "Got first found keys with bad data");
+ok(scalar keys %$cred == 4, "Got first found keys with bad data");
 
-print "# Testing netrc file for a missing corovamilkbar entry\n";
+diag "Testing netrc file for a missing corovamilkbar entry\n";
 $cred = run_credential(['-f', $netrc, 'get'],
 		       { host => 'corovamilkbar' });
 
-ok(scalar keys %$cred, 0, "Got no corovamilkbar keys");
+ok(scalar keys %$cred == 0, "Got no corovamilkbar keys");
 
-print "# Testing netrc file for a github.com entry\n";
+diag "Testing netrc file for a github.com entry\n";
 $cred = run_credential(['-f', $netrc, 'get'],
 		       { host => 'github.com' });
 
-ok(scalar keys %$cred, 2, "Got 2 Github keys");
+ok(scalar keys %$cred == 2, "Got 2 Github keys");
 
-ok($cred->{password}, 'carolknows', "Got correct Github password");
-ok($cred->{username}, 'carol', "Got correct Github username");
+is($cred->{password}, 'carolknows', "Got correct Github password");
+is($cred->{username}, 'carol', "Got correct Github username");
 
-print "# Testing netrc file for a username-specific entry\n";
+diag "Testing netrc file for a username-specific entry\n";
 $cred = run_credential(['-f', $netrc, 'get'],
 		       { host => 'imap', username => 'bob' });
 
-ok(scalar keys %$cred, 2, "Got 2 username-specific keys");
+ok(scalar keys %$cred == 2, "Got 2 username-specific keys");
 
-ok($cred->{password}, 'bobwillknow', "Got correct user-specific password");
-ok($cred->{protocol}, 'imaps', "Got correct user-specific protocol");
+is($cred->{password}, 'bobwillknow', "Got correct user-specific password");
+is($cred->{protocol}, 'imaps', "Got correct user-specific protocol");
 
-print "# Testing netrc file for a host:port-specific entry\n";
+diag "Testing netrc file for a host:port-specific entry\n";
 $cred = run_credential(['-f', $netrc, 'get'],
 		       { host => 'imap2:1099' });
 
-ok(scalar keys %$cred, 2, "Got 2 host:port-specific keys");
+ok(scalar keys %$cred == 2, "Got 2 host:port-specific keys");
 
-ok($cred->{password}, 'tzzknow', "Got correct host:port-specific password");
-ok($cred->{username}, 'tzz', "Got correct host:port-specific username");
+is($cred->{password}, 'tzzknow', "Got correct host:port-specific password");
+is($cred->{username}, 'tzz', "Got correct host:port-specific username");
 
-print "# Testing netrc file that 'host:port kills host' entry\n";
+diag "Testing netrc file that 'host:port kills host' entry\n";
 $cred = run_credential(['-f', $netrc, 'get'],
 		       { host => 'imap2' });
 
-ok(scalar keys %$cred, 2, "Got 2 'host:port kills host' keys");
+ok(scalar keys %$cred == 2, "Got 2 'host:port kills host' keys");
 
-ok($cred->{password}, 'bobwillknow', "Got correct 'host:port kills host' password");
-ok($cred->{username}, 'bob', "Got correct 'host:port kills host' username");
+is($cred->{password}, 'bobwillknow', "Got correct 'host:port kills host' password");
+is($cred->{username}, 'bob', "Got correct 'host:port kills host' username");
+
+diag 'Testing netrc file decryption by git config gpg.program setting\n';
+$cred = run_credential( ['-f', $netrcGpg, 'get']
+                      , { host => 'git-config-gpg' }
+                      );
+
+ok(scalar keys %$cred == 2, 'Got keys decrypted by git config option');
+
+diag 'Testing netrc file decryption by gpg option\n';
+$cred = run_credential( ['-f', $netrcGpg, '-g', 'test.command-option-gpg', 'get']
+                      , { host => 'command-option-gpg' }
+                      );
+
+ok(scalar keys %$cred == 2, 'Got keys decrypted by command option');
 
 sub run_credential
 {
 	my $args = shift @_;
 	my $data = shift @_;
 	my $pid = open2(my $chld_out, my $chld_in,
-			'./git-credential-netrc', @global_credential_args,
+			$gcNetrc, @global_credential_args,
 			@$args);
 
 	die "Couldn't open pipe to netrc credential helper: $!" unless $pid;
diff --git a/contrib/emacs/.gitignore b/contrib/emacs/.gitignore
deleted file mode 100644
index c531d98..0000000
--- a/contrib/emacs/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-*.elc
diff --git a/contrib/emacs/Makefile b/contrib/emacs/Makefile
deleted file mode 100644
index 24d9312..0000000
--- a/contrib/emacs/Makefile
+++ /dev/null
@@ -1,21 +0,0 @@
-## Build and install stuff
-
-EMACS = emacs
-
-ELC = git.elc git-blame.elc
-INSTALL ?= install
-INSTALL_ELC = $(INSTALL) -m 644
-prefix ?= $(HOME)
-emacsdir = $(prefix)/share/emacs/site-lisp
-RM ?= rm -f
-
-all: $(ELC)
-
-install: all
-	$(INSTALL) -d $(DESTDIR)$(emacsdir)
-	$(INSTALL_ELC) $(ELC:.elc=.el) $(ELC) $(DESTDIR)$(emacsdir)
-
-%.elc: %.el
-	$(EMACS) -batch -f batch-byte-compile $<
-
-clean:; $(RM) $(ELC)
diff --git a/contrib/emacs/README b/contrib/emacs/README
index 82368bd..977a16f 100644
--- a/contrib/emacs/README
+++ b/contrib/emacs/README
@@ -1,30 +1,24 @@
-This directory contains various modules for Emacs support.
+This directory used to contain various modules for Emacs support.
 
-To make the modules available to Emacs, you should add this directory
-to your load-path, and then require the modules you want. This can be
-done by adding to your .emacs something like this:
+These were added shortly after Git was first released. Since then
+Emacs's own support for Git got better than what was offered by these
+modes. There are also popular 3rd-party Git modes such as Magit which
+offer replacements for these.
 
-  (add-to-list 'load-path ".../git/contrib/emacs")
-  (require 'git)
-  (require 'git-blame)
-
-
-The following modules are available:
+The following modules were available, and can be dug up from the Git
+history:
 
 * git.el:
 
-  Status manager that displays the state of all the files of the
-  project, and provides easy access to the most frequently used git
-  commands. The user interface is as far as possible compatible with
-  the pcl-cvs mode. It can be started with `M-x git-status'.
+  Wrapper for "git status" that provided access to other git commands.
+
+  Modern alternatives to this include Magit, and VC mode that ships
+  with Emacs.
 
 * git-blame.el:
 
-  Emacs implementation of incremental git-blame.  When you turn it on
-  while viewing a file, the editor buffer will be updated by setting
-  the background of individual lines to a color that reflects which
-  commit it comes from.  And when you move around the buffer, a
-  one-line summary will be shown in the echo area.
+  A wrapper for "git blame" written before Emacs's own vc-annotate
+  mode learned to invoke git-blame, which can be done via C-x v g.
 
 * vc-git.el:
 
diff --git a/contrib/emacs/git-blame.el b/contrib/emacs/git-blame.el
index 510e0f7..6a8a2b8 100644
--- a/contrib/emacs/git-blame.el
+++ b/contrib/emacs/git-blame.el
@@ -1,483 +1,6 @@
-;;; git-blame.el --- Minor mode for incremental blame for Git  -*- coding: utf-8 -*-
-;;
-;; Copyright (C) 2007  David Kågedal
-;;
-;; Authors:    David Kågedal <davidk@lysator.liu.se>
-;; Created:    31 Jan 2007
-;; Message-ID: <87iren2vqx.fsf@morpheus.local>
-;; License:    GPL
-;; Keywords:   git, version control, release management
-;;
-;; Compatibility: Emacs21, Emacs22 and EmacsCVS
-;;                Git 1.5 and up
-
-;; This file is *NOT* part of GNU Emacs.
-;; This file is distributed under the same terms as GNU Emacs.
-
-;; This program is free software; you can redistribute it and/or
-;; modify it under the terms of the GNU General Public License as
-;; published by the Free Software Foundation; either version 2 of
-;; the License, or (at your option) any later version.
-
-;; This program is distributed in the hope that it will be
-;; useful, but WITHOUT ANY WARRANTY; without even the implied
-;; warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
-;; PURPOSE.  See the GNU General Public License for more details.
-
-;; You should have received a copy of the GNU General Public
-;; License along with this program; if not, see
-;; <http://www.gnu.org/licenses/>.
-
-;; http://www.fsf.org/copyleft/gpl.html
-
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;
-;;; Commentary:
-;;
-;; Here is an Emacs implementation of incremental git-blame.  When you
-;; turn it on while viewing a file, the editor buffer will be updated by
-;; setting the background of individual lines to a color that reflects
-;; which commit it comes from.  And when you move around the buffer, a
-;; one-line summary will be shown in the echo area.
-
-;;; Installation:
-;;
-;; To use this package, put it somewhere in `load-path' (or add
-;; directory with git-blame.el to `load-path'), and add the following
-;; line to your .emacs:
-;;
-;;    (require 'git-blame)
-;;
-;; If you do not want to load this package before it is necessary, you
-;; can make use of the `autoload' feature, e.g. by adding to your .emacs
-;; the following lines
-;;
-;;    (autoload 'git-blame-mode "git-blame"
-;;              "Minor mode for incremental blame for Git." t)
-;;
-;; Then first use of `M-x git-blame-mode' would load the package.
-
-;;; Compatibility:
-;;
-;; It requires GNU Emacs 21 or later and Git 1.5.0 and up
-;;
-;; If you'are using Emacs 20, try changing this:
-;;
-;;            (overlay-put ovl 'face (list :background
-;;                                         (cdr (assq 'color (cddddr info)))))
-;;
-;; to
-;;
-;;            (overlay-put ovl 'face (cons 'background-color
-;;                                         (cdr (assq 'color (cddddr info)))))
-
-
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;
-;;; Code:
-
-(eval-when-compile (require 'cl))			      ; to use `push', `pop'
-(require 'format-spec)
-
-(defface git-blame-prefix-face
-  '((((background dark)) (:foreground "gray"
-                          :background "black"))
-    (((background light)) (:foreground "gray"
-                           :background "white"))
-    (t (:weight bold)))
-  "The face used for the hash prefix."
-  :group 'git-blame)
-
-(defgroup git-blame nil
-  "A minor mode showing Git blame information."
-  :group 'git
-  :link '(function-link git-blame-mode))
-
-
-(defcustom git-blame-use-colors t
-  "Use colors to indicate commits in `git-blame-mode'."
-  :type 'boolean
-  :group 'git-blame)
-
-(defcustom git-blame-prefix-format
-  "%h %20A:"
-  "The format of the prefix added to each line in `git-blame'
-mode. The format is passed to `format-spec' with the following format keys:
-
-  %h - the abbreviated hash
-  %H - the full hash
-  %a - the author name
-  %A - the author email
-  %c - the committer name
-  %C - the committer email
-  %s - the commit summary
-"
-  :group 'git-blame)
-
-(defcustom git-blame-mouseover-format
-  "%h %a %A: %s"
-  "The format of the description shown when pointing at a line in
-`git-blame' mode. The format string is passed to `format-spec'
-with the following format keys:
-
-  %h - the abbreviated hash
-  %H - the full hash
-  %a - the author name
-  %A - the author email
-  %c - the committer name
-  %C - the committer email
-  %s - the commit summary
-"
-  :group 'git-blame)
-
-
-(defun git-blame-color-scale (&rest elements)
-  "Given a list, returns a list of triples formed with each
-elements of the list.
-
-a b => bbb bba bab baa abb aba aaa aab"
-  (let (result)
-    (dolist (a elements)
-      (dolist (b elements)
-        (dolist (c elements)
-          (setq result (cons (format "#%s%s%s" a b c) result)))))
-    result))
-
-;; (git-blame-color-scale "0c" "04" "24" "1c" "2c" "34" "14" "3c") =>
-;; ("#3c3c3c" "#3c3c14" "#3c3c34" "#3c3c2c" "#3c3c1c" "#3c3c24"
-;; "#3c3c04" "#3c3c0c" "#3c143c" "#3c1414" "#3c1434" "#3c142c" ...)
-
-(defmacro git-blame-random-pop (l)
-  "Select a random element from L and returns it. Also remove
-selected element from l."
-  ;; only works on lists with unique elements
-  `(let ((e (elt ,l (random (length ,l)))))
-     (setq ,l (remove e ,l))
-     e))
-
-(defvar git-blame-log-oneline-format
-  "format:[%cr] %cn: %s"
-  "*Formatting option used for describing current line in the minibuffer.
-
-This option is used to pass to git log --pretty= command-line option,
-and describe which commit the current line was made.")
-
-(defvar git-blame-dark-colors
-  (git-blame-color-scale "0c" "04" "24" "1c" "2c" "34" "14" "3c")
-  "*List of colors (format #RGB) to use in a dark environment.
-
-To check out the list, evaluate (list-colors-display git-blame-dark-colors).")
-
-(defvar git-blame-light-colors
-  (git-blame-color-scale "c4" "d4" "cc" "dc" "f4" "e4" "fc" "ec")
-  "*List of colors (format #RGB) to use in a light environment.
-
-To check out the list, evaluate (list-colors-display git-blame-light-colors).")
-
-(defvar git-blame-colors '()
-  "Colors used by git-blame. The list is built once when activating git-blame
-minor mode.")
-
-(defvar git-blame-ancient-color "dark green"
-  "*Color to be used for ancient commit.")
-
-(defvar git-blame-autoupdate t
-  "*Automatically update the blame display while editing")
-
-(defvar git-blame-proc nil
-  "The running git-blame process")
-(make-variable-buffer-local 'git-blame-proc)
-
-(defvar git-blame-overlays nil
-  "The git-blame overlays used in the current buffer.")
-(make-variable-buffer-local 'git-blame-overlays)
-
-(defvar git-blame-cache nil
-  "A cache of git-blame information for the current buffer")
-(make-variable-buffer-local 'git-blame-cache)
-
-(defvar git-blame-idle-timer nil
-  "An idle timer that updates the blame")
-(make-variable-buffer-local 'git-blame-cache)
-
-(defvar git-blame-update-queue nil
-  "A queue of update requests")
-(make-variable-buffer-local 'git-blame-update-queue)
-
-;; FIXME: docstrings
-(defvar git-blame-file nil)
-(defvar git-blame-current nil)
-
-(defvar git-blame-mode nil)
-(make-variable-buffer-local 'git-blame-mode)
-
-(defvar git-blame-mode-line-string " blame"
-  "String to display on the mode line when git-blame is active.")
-
-(or (assq 'git-blame-mode minor-mode-alist)
-    (setq minor-mode-alist
-	  (cons '(git-blame-mode git-blame-mode-line-string) minor-mode-alist)))
-
-;;;###autoload
-(defun git-blame-mode (&optional arg)
-  "Toggle minor mode for displaying Git blame
-
-With prefix ARG, turn the mode on if ARG is positive."
-  (interactive "P")
-  (cond
-   ((null arg)
-    (if git-blame-mode (git-blame-mode-off) (git-blame-mode-on)))
-   ((> (prefix-numeric-value arg) 0) (git-blame-mode-on))
-   (t (git-blame-mode-off))))
-
-(defun git-blame-mode-on ()
-  "Turn on git-blame mode.
-
-See also function `git-blame-mode'."
-  (make-local-variable 'git-blame-colors)
-  (if git-blame-autoupdate
-      (add-hook 'after-change-functions 'git-blame-after-change nil t)
-    (remove-hook 'after-change-functions 'git-blame-after-change t))
-  (git-blame-cleanup)
-  (let ((bgmode (cdr (assoc 'background-mode (frame-parameters)))))
-    (if (eq bgmode 'dark)
-	(setq git-blame-colors git-blame-dark-colors)
-      (setq git-blame-colors git-blame-light-colors)))
-  (setq git-blame-cache (make-hash-table :test 'equal))
-  (setq git-blame-mode t)
-  (git-blame-run))
-
-(defun git-blame-mode-off ()
-  "Turn off git-blame mode.
-
-See also function `git-blame-mode'."
-  (git-blame-cleanup)
-  (if git-blame-idle-timer (cancel-timer git-blame-idle-timer))
-  (setq git-blame-mode nil))
-
-;;;###autoload
-(defun git-reblame ()
-  "Recalculate all blame information in the current buffer"
-  (interactive)
-  (unless git-blame-mode
-    (error "Git-blame is not active"))
-
-  (git-blame-cleanup)
-  (git-blame-run))
-
-(defun git-blame-run (&optional startline endline)
-  (if git-blame-proc
-      ;; Should maybe queue up a new run here
-      (message "Already running git blame")
-    (let ((display-buf (current-buffer))
-          (blame-buf (get-buffer-create
-                      (concat " git blame for " (buffer-name))))
-          (args '("--incremental" "--contents" "-")))
-      (if startline
-          (setq args (append args
-                             (list "-L" (format "%d,%d" startline endline)))))
-      (setq args (append args
-                         (list (file-name-nondirectory buffer-file-name))))
-      (setq git-blame-proc
-            (apply 'start-process
-                   "git-blame" blame-buf
-                   "git" "blame"
-                   args))
-      (with-current-buffer blame-buf
-        (erase-buffer)
-        (make-local-variable 'git-blame-file)
-        (make-local-variable 'git-blame-current)
-        (setq git-blame-file display-buf)
-        (setq git-blame-current nil))
-      (set-process-filter git-blame-proc 'git-blame-filter)
-      (set-process-sentinel git-blame-proc 'git-blame-sentinel)
-      (process-send-region git-blame-proc (point-min) (point-max))
-      (process-send-eof git-blame-proc))))
-
-(defun remove-git-blame-text-properties (start end)
-  (let ((modified (buffer-modified-p))
-        (inhibit-read-only t))
-    (remove-text-properties start end '(point-entered nil))
-    (set-buffer-modified-p modified)))
-
-(defun git-blame-cleanup ()
-  "Remove all blame properties"
-    (mapc 'delete-overlay git-blame-overlays)
-    (setq git-blame-overlays nil)
-    (remove-git-blame-text-properties (point-min) (point-max)))
-
-(defun git-blame-update-region (start end)
-  "Rerun blame to get updates between START and END"
-  (let ((overlays (overlays-in start end)))
-    (while overlays
-      (let ((overlay (pop overlays)))
-        (if (< (overlay-start overlay) start)
-            (setq start (overlay-start overlay)))
-        (if (> (overlay-end overlay) end)
-            (setq end (overlay-end overlay)))
-        (setq git-blame-overlays (delete overlay git-blame-overlays))
-        (delete-overlay overlay))))
-  (remove-git-blame-text-properties start end)
-  ;; We can be sure that start and end are at line breaks
-  (git-blame-run (1+ (count-lines (point-min) start))
-                 (count-lines (point-min) end)))
-
-(defun git-blame-sentinel (proc status)
-  (with-current-buffer (process-buffer proc)
-    (with-current-buffer git-blame-file
-      (setq git-blame-proc nil)
-      (if git-blame-update-queue
-          (git-blame-delayed-update))))
-  ;;(kill-buffer (process-buffer proc))
-  ;;(message "git blame finished")
-  )
-
-(defvar in-blame-filter nil)
-
-(defun git-blame-filter (proc str)
-  (with-current-buffer (process-buffer proc)
-    (save-excursion
-      (goto-char (process-mark proc))
-      (insert-before-markers str)
-      (goto-char (point-min))
-      (unless in-blame-filter
-        (let ((more t)
-              (in-blame-filter t))
-          (while more
-            (setq more (git-blame-parse))))))))
-
-(defun git-blame-parse ()
-  (cond ((looking-at "\\([0-9a-f]\\{40\\}\\) \\([0-9]+\\) \\([0-9]+\\) \\([0-9]+\\)\n")
-         (let ((hash (match-string 1))
-               (src-line (string-to-number (match-string 2)))
-               (res-line (string-to-number (match-string 3)))
-               (num-lines (string-to-number (match-string 4))))
-           (delete-region (point) (match-end 0))
-           (setq git-blame-current (list (git-blame-new-commit hash)
-                                         src-line res-line num-lines)))
-         t)
-        ((looking-at "\\([a-z-]+\\) \\(.+\\)\n")
-         (let ((key (match-string 1))
-               (value (match-string 2)))
-           (delete-region (point) (match-end 0))
-           (git-blame-add-info (car git-blame-current) key value)
-           (when (string= key "filename")
-             (git-blame-create-overlay (car git-blame-current)
-                                       (caddr git-blame-current)
-                                       (cadddr git-blame-current))
-             (setq git-blame-current nil)))
-         t)
-        (t
-         nil)))
-
-(defun git-blame-new-commit (hash)
-  (with-current-buffer git-blame-file
-    (or (gethash hash git-blame-cache)
-        ;; Assign a random color to each new commit info
-        ;; Take care not to select the same color multiple times
-        (let* ((color (if git-blame-colors
-                          (git-blame-random-pop git-blame-colors)
-                        git-blame-ancient-color))
-               (info `(,hash (color . ,color))))
-          (puthash hash info git-blame-cache)
-          info))))
-
-(defun git-blame-create-overlay (info start-line num-lines)
-  (with-current-buffer git-blame-file
-    (save-excursion
-      (let ((inhibit-point-motion-hooks t)
-            (inhibit-modification-hooks t))
-        (goto-char (point-min))
-        (forward-line (1- start-line))
-        (let* ((start (point))
-               (end (progn (forward-line num-lines) (point)))
-               (ovl (make-overlay start end))
-               (hash (car info))
-               (spec `((?h . ,(substring hash 0 6))
-                       (?H . ,hash)
-                       (?a . ,(git-blame-get-info info 'author))
-                       (?A . ,(git-blame-get-info info 'author-mail))
-                       (?c . ,(git-blame-get-info info 'committer))
-                       (?C . ,(git-blame-get-info info 'committer-mail))
-                       (?s . ,(git-blame-get-info info 'summary)))))
-          (push ovl git-blame-overlays)
-          (overlay-put ovl 'git-blame info)
-          (overlay-put ovl 'help-echo
-                       (format-spec git-blame-mouseover-format spec))
-          (if git-blame-use-colors
-              (overlay-put ovl 'face (list :background
-                                           (cdr (assq 'color (cdr info))))))
-          (overlay-put ovl 'line-prefix
-                       (propertize (format-spec git-blame-prefix-format spec)
-                                   'face 'git-blame-prefix-face)))))))
-
-(defun git-blame-add-info (info key value)
-  (nconc info (list (cons (intern key) value))))
-
-(defun git-blame-get-info (info key)
-  (cdr (assq key (cdr info))))
-
-(defun git-blame-current-commit ()
-  (let ((info (get-char-property (point) 'git-blame)))
-    (if info
-        (car info)
-      (error "No commit info"))))
-
-(defun git-describe-commit (hash)
-  (with-temp-buffer
-    (call-process "git" nil t nil
-                  "log" "-1"
-		  (concat "--pretty=" git-blame-log-oneline-format)
-                  hash)
-    (buffer-substring (point-min) (point-max))))
-
-(defvar git-blame-last-identification nil)
-(make-variable-buffer-local 'git-blame-last-identification)
-(defun git-blame-identify (&optional hash)
-  (interactive)
-  (let ((info (gethash (or hash (git-blame-current-commit)) git-blame-cache)))
-    (when (and info (not (eq info git-blame-last-identification)))
-      (message "%s" (nth 4 info))
-      (setq git-blame-last-identification info))))
-
-;; (defun git-blame-after-save ()
-;;   (when git-blame-mode
-;;     (git-blame-cleanup)
-;;     (git-blame-run)))
-;; (add-hook 'after-save-hook 'git-blame-after-save)
-
-(defun git-blame-after-change (start end length)
-  (when git-blame-mode
-    (git-blame-enq-update start end)))
-
-(defvar git-blame-last-update nil)
-(make-variable-buffer-local 'git-blame-last-update)
-(defun git-blame-enq-update (start end)
-  "Mark the region between START and END as needing blame update"
-  ;; Try to be smart and avoid multiple callouts for sequential
-  ;; editing
-  (cond ((and git-blame-last-update
-              (= start (cdr git-blame-last-update)))
-         (setcdr git-blame-last-update end))
-        ((and git-blame-last-update
-              (= end (car git-blame-last-update)))
-         (setcar git-blame-last-update start))
-        (t
-         (setq git-blame-last-update (cons start end))
-         (setq git-blame-update-queue (nconc git-blame-update-queue
-                                             (list git-blame-last-update)))))
-  (unless (or git-blame-proc git-blame-idle-timer)
-    (setq git-blame-idle-timer
-          (run-with-idle-timer 0.5 nil 'git-blame-delayed-update))))
-
-(defun git-blame-delayed-update ()
-  (setq git-blame-idle-timer nil)
-  (if git-blame-update-queue
-      (let ((first (pop git-blame-update-queue))
-            (inhibit-point-motion-hooks t))
-        (git-blame-update-region (car first) (cdr first)))))
-
-(provide 'git-blame)
-
-;;; git-blame.el ends here
+(error "git-blame.el no longer ships with git. It's recommended
+to replace its use with Emacs's own vc-annotate. See
+contrib/emacs/README in git's
+sources (https://github.com/git/git/blob/master/contrib/emacs/README)
+for more info on suggested alternatives and for why this
+happened.")
diff --git a/contrib/emacs/git.el b/contrib/emacs/git.el
index 97919f2..03f9262 100644
--- a/contrib/emacs/git.el
+++ b/contrib/emacs/git.el
@@ -1,1704 +1,6 @@
-;;; git.el --- A user interface for git
-
-;; Copyright (C) 2005, 2006, 2007, 2008, 2009 Alexandre Julliard <julliard@winehq.org>
-
-;; Version: 1.0
-
-;; This program is free software; you can redistribute it and/or
-;; modify it under the terms of the GNU General Public License as
-;; published by the Free Software Foundation; either version 2 of
-;; the License, or (at your option) any later version.
-;;
-;; This program is distributed in the hope that it will be
-;; useful, but WITHOUT ANY WARRANTY; without even the implied
-;; warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
-;; PURPOSE.  See the GNU General Public License for more details.
-;;
-;; You should have received a copy of the GNU General Public
-;; License along with this program; if not, see
-;; <http://www.gnu.org/licenses/>.
-
-;;; Commentary:
-
-;; This file contains an interface for the git version control
-;; system. It provides easy access to the most frequently used git
-;; commands. The user interface is as far as possible identical to
-;; that of the PCL-CVS mode.
-;;
-;; To install: put this file on the load-path and place the following
-;; in your .emacs file:
-;;
-;;    (require 'git)
-;;
-;; To start: `M-x git-status'
-;;
-;; TODO
-;;  - diff against other branch
-;;  - renaming files from the status buffer
-;;  - creating tags
-;;  - fetch/pull
-;;  - revlist browser
-;;  - git-show-branch browser
-;;
-
-;;; Compatibility:
-;;
-;; This file works on GNU Emacs 21 or later. It may work on older
-;; versions but this is not guaranteed.
-;;
-;; It may work on XEmacs 21, provided that you first install the ewoc
-;; and log-edit packages.
-;;
-
-(eval-when-compile (require 'cl))
-(require 'ewoc)
-(require 'log-edit)
-(require 'easymenu)
-
-
-;;;; Customizations
-;;;; ------------------------------------------------------------
-
-(defgroup git nil
-  "A user interface for the git versioning system."
-  :group 'tools)
-
-(defcustom git-committer-name nil
-  "User name to use for commits.
-The default is to fall back to the repository config,
-then to `add-log-full-name' and then to `user-full-name'."
-  :group 'git
-  :type '(choice (const :tag "Default" nil)
-                 (string :tag "Name")))
-
-(defcustom git-committer-email nil
-  "Email address to use for commits.
-The default is to fall back to the git repository config,
-then to `add-log-mailing-address' and then to `user-mail-address'."
-  :group 'git
-  :type '(choice (const :tag "Default" nil)
-                 (string :tag "Email")))
-
-(defcustom git-commits-coding-system nil
-  "Default coding system for the log message of git commits."
-  :group 'git
-  :type '(choice (const :tag "From repository config" nil)
-                 (coding-system)))
-
-(defcustom git-append-signed-off-by nil
-  "Whether to append a Signed-off-by line to the commit message before editing."
-  :group 'git
-  :type 'boolean)
-
-(defcustom git-reuse-status-buffer t
-  "Whether `git-status' should try to reuse an existing buffer
-if there is already one that displays the same directory."
-  :group 'git
-  :type 'boolean)
-
-(defcustom git-per-dir-ignore-file ".gitignore"
-  "Name of the per-directory ignore file."
-  :group 'git
-  :type 'string)
-
-(defcustom git-show-uptodate nil
-  "Whether to display up-to-date files."
-  :group 'git
-  :type 'boolean)
-
-(defcustom git-show-ignored nil
-  "Whether to display ignored files."
-  :group 'git
-  :type 'boolean)
-
-(defcustom git-show-unknown t
-  "Whether to display unknown files."
-  :group 'git
-  :type 'boolean)
-
-
-(defface git-status-face
-  '((((class color) (background light)) (:foreground "purple"))
-    (((class color) (background dark)) (:foreground "salmon")))
-  "Git mode face used to highlight added and modified files."
-  :group 'git)
-
-(defface git-unmerged-face
-  '((((class color) (background light)) (:foreground "red" :bold t))
-    (((class color) (background dark)) (:foreground "red" :bold t)))
-  "Git mode face used to highlight unmerged files."
-  :group 'git)
-
-(defface git-unknown-face
-  '((((class color) (background light)) (:foreground "goldenrod" :bold t))
-    (((class color) (background dark)) (:foreground "goldenrod" :bold t)))
-  "Git mode face used to highlight unknown files."
-  :group 'git)
-
-(defface git-uptodate-face
-  '((((class color) (background light)) (:foreground "grey60"))
-    (((class color) (background dark)) (:foreground "grey40")))
-  "Git mode face used to highlight up-to-date files."
-  :group 'git)
-
-(defface git-ignored-face
-  '((((class color) (background light)) (:foreground "grey60"))
-    (((class color) (background dark)) (:foreground "grey40")))
-  "Git mode face used to highlight ignored files."
-  :group 'git)
-
-(defface git-mark-face
-  '((((class color) (background light)) (:foreground "red" :bold t))
-    (((class color) (background dark)) (:foreground "tomato" :bold t)))
-  "Git mode face used for the file marks."
-  :group 'git)
-
-(defface git-header-face
-  '((((class color) (background light)) (:foreground "blue"))
-    (((class color) (background dark)) (:foreground "blue")))
-  "Git mode face used for commit headers."
-  :group 'git)
-
-(defface git-separator-face
-  '((((class color) (background light)) (:foreground "brown"))
-    (((class color) (background dark)) (:foreground "brown")))
-  "Git mode face used for commit separator."
-  :group 'git)
-
-(defface git-permission-face
-  '((((class color) (background light)) (:foreground "green" :bold t))
-    (((class color) (background dark)) (:foreground "green" :bold t)))
-  "Git mode face used for permission changes."
-  :group 'git)
-
-
-;;;; Utilities
-;;;; ------------------------------------------------------------
-
-(defconst git-log-msg-separator "--- log message follows this line ---")
-
-(defvar git-log-edit-font-lock-keywords
-  `(("^\\(Author:\\|Date:\\|Merge:\\|Signed-off-by:\\)\\(.*\\)$"
-     (1 font-lock-keyword-face)
-     (2 font-lock-function-name-face))
-    (,(concat "^\\(" (regexp-quote git-log-msg-separator) "\\)$")
-     (1 font-lock-comment-face))))
-
-(defun git-get-env-strings (env)
-  "Build a list of NAME=VALUE strings from a list of environment strings."
-  (mapcar (lambda (entry) (concat (car entry) "=" (cdr entry))) env))
-
-(defun git-call-process (buffer &rest args)
-  "Wrapper for call-process that sets environment strings."
-  (apply #'call-process "git" nil buffer nil args))
-
-(defun git-call-process-display-error (&rest args)
-  "Wrapper for call-process that displays error messages."
-  (let* ((dir default-directory)
-         (buffer (get-buffer-create "*Git Command Output*"))
-         (ok (with-current-buffer buffer
-               (let ((default-directory dir)
-                     (buffer-read-only nil))
-                 (erase-buffer)
-                 (eq 0 (apply #'git-call-process (list buffer t) args))))))
-    (unless ok (display-message-or-buffer buffer))
-    ok))
-
-(defun git-call-process-string (&rest args)
-  "Wrapper for call-process that returns the process output as a string,
-or nil if the git command failed."
-  (with-temp-buffer
-    (and (eq 0 (apply #'git-call-process t args))
-         (buffer-string))))
-
-(defun git-call-process-string-display-error (&rest args)
-  "Wrapper for call-process that displays error message and returns
-the process output as a string, or nil if the git command failed."
-  (with-temp-buffer
-    (if (eq 0 (apply #'git-call-process (list t t) args))
-        (buffer-string)
-      (display-message-or-buffer (current-buffer))
-      nil)))
-
-(defun git-run-process-region (buffer start end program args)
-  "Run a git process with a buffer region as input."
-  (let ((output-buffer (current-buffer))
-        (dir default-directory))
-    (with-current-buffer buffer
-      (cd dir)
-      (apply #'call-process-region start end program
-             nil (list output-buffer t) nil args))))
-
-(defun git-run-command-buffer (buffer-name &rest args)
-  "Run a git command, sending the output to a buffer named BUFFER-NAME."
-  (let ((dir default-directory)
-        (buffer (get-buffer-create buffer-name)))
-    (message "Running git %s..." (car args))
-    (with-current-buffer buffer
-      (let ((default-directory dir)
-            (buffer-read-only nil))
-        (erase-buffer)
-        (apply #'git-call-process buffer args)))
-    (message "Running git %s...done" (car args))
-    buffer))
-
-(defun git-run-command-region (buffer start end env &rest args)
-  "Run a git command with specified buffer region as input."
-  (with-temp-buffer
-    (if (eq 0 (if env
-                  (git-run-process-region
-                   buffer start end "env"
-                   (append (git-get-env-strings env) (list "git") args))
-                (git-run-process-region buffer start end "git" args)))
-        (buffer-string)
-      (display-message-or-buffer (current-buffer))
-      nil)))
-
-(defun git-run-hook (hook env &rest args)
-  "Run a git hook and display its output if any."
-  (let ((dir default-directory)
-        (hook-name (expand-file-name (concat ".git/hooks/" hook))))
-    (or (not (file-executable-p hook-name))
-        (let (status (buffer (get-buffer-create "*Git Hook Output*")))
-          (with-current-buffer buffer
-            (erase-buffer)
-            (cd dir)
-            (setq status
-                  (if env
-                      (apply #'call-process "env" nil (list buffer t) nil
-                             (append (git-get-env-strings env) (list hook-name) args))
-                    (apply #'call-process hook-name nil (list buffer t) nil args))))
-          (display-message-or-buffer buffer)
-          (eq 0 status)))))
-
-(defun git-get-string-sha1 (string)
-  "Read a SHA1 from the specified string."
-  (and string
-       (string-match "[0-9a-f]\\{40\\}" string)
-       (match-string 0 string)))
-
-(defun git-get-committer-name ()
-  "Return the name to use as GIT_COMMITTER_NAME."
-  ; copied from log-edit
-  (or git-committer-name
-      (git-config "user.name")
-      (and (boundp 'add-log-full-name) add-log-full-name)
-      (and (fboundp 'user-full-name) (user-full-name))
-      (and (boundp 'user-full-name) user-full-name)))
-
-(defun git-get-committer-email ()
-  "Return the email address to use as GIT_COMMITTER_EMAIL."
-  ; copied from log-edit
-  (or git-committer-email
-      (git-config "user.email")
-      (and (boundp 'add-log-mailing-address) add-log-mailing-address)
-      (and (fboundp 'user-mail-address) (user-mail-address))
-      (and (boundp 'user-mail-address) user-mail-address)))
-
-(defun git-get-commits-coding-system ()
-  "Return the coding system to use for commits."
-  (let ((repo-config (git-config "i18n.commitencoding")))
-    (or git-commits-coding-system
-        (and repo-config
-             (fboundp 'locale-charset-to-coding-system)
-             (locale-charset-to-coding-system repo-config))
-      'utf-8)))
-
-(defun git-get-logoutput-coding-system ()
-  "Return the coding system used for git-log output."
-  (let ((repo-config (or (git-config "i18n.logoutputencoding")
-                         (git-config "i18n.commitencoding"))))
-    (or git-commits-coding-system
-        (and repo-config
-             (fboundp 'locale-charset-to-coding-system)
-             (locale-charset-to-coding-system repo-config))
-      'utf-8)))
-
-(defun git-escape-file-name (name)
-  "Escape a file name if necessary."
-  (if (string-match "[\n\t\"\\]" name)
-      (concat "\""
-              (mapconcat (lambda (c)
-                   (case c
-                     (?\n "\\n")
-                     (?\t "\\t")
-                     (?\\ "\\\\")
-                     (?\" "\\\"")
-                     (t (char-to-string c))))
-                 name "")
-              "\"")
-    name))
-
-(defun git-success-message (text files)
-  "Print a success message after having handled FILES."
-  (let ((n (length files)))
-    (if (equal n 1)
-        (message "%s %s" text (car files))
-      (message "%s %d files" text n))))
-
-(defun git-get-top-dir (dir)
-  "Retrieve the top-level directory of a git tree."
-  (let ((cdup (with-output-to-string
-                (with-current-buffer standard-output
-                  (cd dir)
-                  (unless (eq 0 (git-call-process t "rev-parse" "--show-cdup"))
-                    (error "cannot find top-level git tree for %s." dir))))))
-    (expand-file-name (concat (file-name-as-directory dir)
-                              (car (split-string cdup "\n"))))))
-
-;stolen from pcl-cvs
-(defun git-append-to-ignore (file)
-  "Add a file name to the ignore file in its directory."
-  (let* ((fullname (expand-file-name file))
-         (dir (file-name-directory fullname))
-         (name (file-name-nondirectory fullname))
-         (ignore-name (expand-file-name git-per-dir-ignore-file dir))
-         (created (not (file-exists-p ignore-name))))
-  (save-window-excursion
-    (set-buffer (find-file-noselect ignore-name))
-    (goto-char (point-max))
-    (unless (zerop (current-column)) (insert "\n"))
-    (insert "/" name "\n")
-    (sort-lines nil (point-min) (point-max))
-    (save-buffer))
-  (when created
-    (git-call-process nil "update-index" "--add" "--" (file-relative-name ignore-name)))
-  (git-update-status-files (list (file-relative-name ignore-name)))))
-
-; propertize definition for XEmacs, stolen from erc-compat
-(eval-when-compile
-  (unless (fboundp 'propertize)
-    (defun propertize (string &rest props)
-      (let ((string (copy-sequence string)))
-        (while props
-          (put-text-property 0 (length string) (nth 0 props) (nth 1 props) string)
-          (setq props (cddr props)))
-        string))))
-
-;;;; Wrappers for basic git commands
-;;;; ------------------------------------------------------------
-
-(defun git-rev-parse (rev)
-  "Parse a revision name and return its SHA1."
-  (git-get-string-sha1
-   (git-call-process-string "rev-parse" rev)))
-
-(defun git-config (key)
-  "Retrieve the value associated to KEY in the git repository config file."
-  (let ((str (git-call-process-string "config" key)))
-    (and str (car (split-string str "\n")))))
-
-(defun git-symbolic-ref (ref)
-  "Wrapper for the git-symbolic-ref command."
-  (let ((str (git-call-process-string "symbolic-ref" ref)))
-    (and str (car (split-string str "\n")))))
-
-(defun git-update-ref (ref newval &optional oldval reason)
-  "Update a reference by calling git-update-ref."
-  (let ((args (and oldval (list oldval))))
-    (when newval (push newval args))
-    (push ref args)
-    (when reason
-     (push reason args)
-     (push "-m" args))
-    (unless newval (push "-d" args))
-    (apply 'git-call-process-display-error "update-ref" args)))
-
-(defun git-for-each-ref (&rest specs)
-  "Return a list of refs using git-for-each-ref.
-Each entry is a cons of (SHORT-NAME . FULL-NAME)."
-  (let (refs)
-    (with-temp-buffer
-      (apply #'git-call-process t "for-each-ref" "--format=%(refname)" specs)
-      (goto-char (point-min))
-      (while (re-search-forward "^[^/\n]+/[^/\n]+/\\(.+\\)$" nil t)
-	(push (cons (match-string 1) (match-string 0)) refs)))
-    (nreverse refs)))
-
-(defun git-read-tree (tree &optional index-file)
-  "Read a tree into the index file."
-  (let ((process-environment
-         (append (and index-file (list (concat "GIT_INDEX_FILE=" index-file))) process-environment)))
-    (apply 'git-call-process-display-error "read-tree" (if tree (list tree)))))
-
-(defun git-write-tree (&optional index-file)
-  "Call git-write-tree and return the resulting tree SHA1 as a string."
-  (let ((process-environment
-         (append (and index-file (list (concat "GIT_INDEX_FILE=" index-file))) process-environment)))
-    (git-get-string-sha1
-     (git-call-process-string-display-error "write-tree"))))
-
-(defun git-commit-tree (buffer tree parent)
-  "Create a commit and possibly update HEAD.
-Create a commit with the message in BUFFER using the tree with hash TREE.
-Use PARENT as the parent of the new commit. If PARENT is the current \"HEAD\",
-update the \"HEAD\" reference to the new commit."
-  (let ((author-name (git-get-committer-name))
-        (author-email (git-get-committer-email))
-        (subject "commit (initial): ")
-        author-date log-start log-end args coding-system-for-write)
-    (when parent
-      (setq subject "commit: ")
-      (push "-p" args)
-      (push parent args))
-    (with-current-buffer buffer
-      (goto-char (point-min))
-      (if
-          (setq log-start (re-search-forward (concat "^" (regexp-quote git-log-msg-separator) "\n") nil t))
-          (save-restriction
-            (narrow-to-region (point-min) log-start)
-            (goto-char (point-min))
-            (when (re-search-forward "^Author: +\\(.*?\\) *<\\(.*\\)> *$" nil t)
-              (setq author-name (match-string 1)
-                    author-email (match-string 2)))
-            (goto-char (point-min))
-            (when (re-search-forward "^Date: +\\(.*\\)$" nil t)
-              (setq author-date (match-string 1)))
-            (goto-char (point-min))
-            (when (re-search-forward "^Merge: +\\(.*\\)" nil t)
-              (setq subject "commit (merge): ")
-              (dolist (parent (split-string (match-string 1) " +" t))
-                (push "-p" args)
-                (push parent args))))
-        (setq log-start (point-min)))
-      (setq log-end (point-max))
-      (goto-char log-start)
-      (when (re-search-forward ".*$" nil t)
-        (setq subject (concat subject (match-string 0))))
-      (setq coding-system-for-write buffer-file-coding-system))
-    (let ((commit
-           (git-get-string-sha1
-            (let ((env `(("GIT_AUTHOR_NAME" . ,author-name)
-                         ("GIT_AUTHOR_EMAIL" . ,author-email)
-                         ("GIT_COMMITTER_NAME" . ,(git-get-committer-name))
-                         ("GIT_COMMITTER_EMAIL" . ,(git-get-committer-email)))))
-              (when author-date (push `("GIT_AUTHOR_DATE" . ,author-date) env))
-              (apply #'git-run-command-region
-                     buffer log-start log-end env
-                     "commit-tree" tree (nreverse args))))))
-      (when commit (git-update-ref "HEAD" commit parent subject))
-      commit)))
-
-(defun git-empty-db-p ()
-  "Check if the git db is empty (no commit done yet)."
-  (not (eq 0 (git-call-process nil "rev-parse" "--verify" "HEAD"))))
-
-(defun git-get-merge-heads ()
-  "Retrieve the merge heads from the MERGE_HEAD file if present."
-  (let (heads)
-    (when (file-readable-p ".git/MERGE_HEAD")
-      (with-temp-buffer
-        (insert-file-contents ".git/MERGE_HEAD" nil nil nil t)
-        (goto-char (point-min))
-        (while (re-search-forward "[0-9a-f]\\{40\\}" nil t)
-          (push (match-string 0) heads))))
-    (nreverse heads)))
-
-(defun git-get-commit-description (commit)
-  "Get a one-line description of COMMIT."
-  (let ((coding-system-for-read (git-get-logoutput-coding-system)))
-    (let ((descr (git-call-process-string "log" "--max-count=1" "--pretty=oneline" commit)))
-      (if (and descr (string-match "\\`\\([0-9a-f]\\{40\\}\\) *\\(.*\\)$" descr))
-          (concat (substring (match-string 1 descr) 0 10) " - " (match-string 2 descr))
-        descr))))
-
-;;;; File info structure
-;;;; ------------------------------------------------------------
-
-; fileinfo structure stolen from pcl-cvs
-(defstruct (git-fileinfo
-            (:copier nil)
-            (:constructor git-create-fileinfo (state name &optional old-perm new-perm rename-state orig-name marked))
-            (:conc-name git-fileinfo->))
-  marked              ;; t/nil
-  state               ;; current state
-  name                ;; file name
-  old-perm new-perm   ;; permission flags
-  rename-state        ;; rename or copy state
-  orig-name           ;; original name for renames or copies
-  needs-update        ;; whether file needs to be updated
-  needs-refresh)      ;; whether file needs to be refreshed
-
-(defvar git-status nil)
-
-(defun git-set-fileinfo-state (info state)
-  "Set the state of a file info."
-  (unless (eq (git-fileinfo->state info) state)
-    (setf (git-fileinfo->state info) state
-	  (git-fileinfo->new-perm info) (git-fileinfo->old-perm info)
-          (git-fileinfo->rename-state info) nil
-          (git-fileinfo->orig-name info) nil
-          (git-fileinfo->needs-update info) nil
-          (git-fileinfo->needs-refresh info) t)))
-
-(defun git-status-filenames-map (status func files &rest args)
-  "Apply FUNC to the status files names in the FILES list.
-The list must be sorted."
-  (when files
-    (let ((file (pop files))
-          (node (ewoc-nth status 0)))
-      (while (and file node)
-        (let* ((info (ewoc-data node))
-               (name (git-fileinfo->name info)))
-          (if (string-lessp name file)
-              (setq node (ewoc-next status node))
-            (if (string-equal name file)
-                (apply func info args))
-            (setq file (pop files))))))))
-
-(defun git-set-filenames-state (status files state)
-  "Set the state of a list of named files. The list must be sorted"
-  (when files
-    (git-status-filenames-map status #'git-set-fileinfo-state files state)
-    (unless state  ;; delete files whose state has been set to nil
-      (ewoc-filter status (lambda (info) (git-fileinfo->state info))))))
-
-(defun git-state-code (code)
-  "Convert from a string to a added/deleted/modified state."
-  (case (string-to-char code)
-    (?M 'modified)
-    (?? 'unknown)
-    (?A 'added)
-    (?D 'deleted)
-    (?U 'unmerged)
-    (?T 'modified)
-    (t nil)))
-
-(defun git-status-code-as-string (code)
-  "Format a git status code as string."
-  (case code
-    ('modified (propertize "Modified" 'face 'git-status-face))
-    ('unknown  (propertize "Unknown " 'face 'git-unknown-face))
-    ('added    (propertize "Added   " 'face 'git-status-face))
-    ('deleted  (propertize "Deleted " 'face 'git-status-face))
-    ('unmerged (propertize "Unmerged" 'face 'git-unmerged-face))
-    ('uptodate (propertize "Uptodate" 'face 'git-uptodate-face))
-    ('ignored  (propertize "Ignored " 'face 'git-ignored-face))
-    (t "?       ")))
-
-(defun git-file-type-as-string (old-perm new-perm)
-  "Return a string describing the file type based on its permissions."
-  (let* ((old-type (lsh (or old-perm 0) -9))
-	 (new-type (lsh (or new-perm 0) -9))
-	 (str (case new-type
-		(64  ;; file
-		 (case old-type
-		   (64 nil)
-		   (80 "   (type change symlink -> file)")
-		   (112 "   (type change subproject -> file)")))
-		 (80  ;; symlink
-		  (case old-type
-		    (64 "   (type change file -> symlink)")
-		    (112 "   (type change subproject -> symlink)")
-		    (t "   (symlink)")))
-		  (112  ;; subproject
-		   (case old-type
-		     (64 "   (type change file -> subproject)")
-		     (80 "   (type change symlink -> subproject)")
-		     (t "   (subproject)")))
-                  (72 nil)  ;; directory (internal, not a real git state)
-		  (0  ;; deleted or unknown
-		   (case old-type
-		     (80 "   (symlink)")
-		     (112 "   (subproject)")))
-		  (t (format "   (unknown type %o)" new-type)))))
-    (cond (str (propertize str 'face 'git-status-face))
-          ((eq new-type 72) "/")
-          (t ""))))
-
-(defun git-rename-as-string (info)
-  "Return a string describing the copy or rename associated with INFO, or an empty string if none."
-  (let ((state (git-fileinfo->rename-state info)))
-    (if state
-        (propertize
-         (concat "   ("
-                 (if (eq state 'copy) "copied from "
-                   (if (eq (git-fileinfo->state info) 'added) "renamed from "
-                     "renamed to "))
-                 (git-escape-file-name (git-fileinfo->orig-name info))
-                 ")") 'face 'git-status-face)
-      "")))
-
-(defun git-permissions-as-string (old-perm new-perm)
-  "Format a permission change as string."
-  (propertize
-   (if (or (not old-perm)
-           (not new-perm)
-           (eq 0 (logand ?\111 (logxor old-perm new-perm))))
-       "  "
-     (if (eq 0 (logand ?\111 old-perm)) "+x" "-x"))
-  'face 'git-permission-face))
-
-(defun git-fileinfo-prettyprint (info)
-  "Pretty-printer for the git-fileinfo structure."
-  (let ((old-perm (git-fileinfo->old-perm info))
-	(new-perm (git-fileinfo->new-perm info)))
-    (insert (concat "   " (if (git-fileinfo->marked info) (propertize "*" 'face 'git-mark-face) " ")
-		    " " (git-status-code-as-string (git-fileinfo->state info))
-		    " " (git-permissions-as-string old-perm new-perm)
-		    "  " (git-escape-file-name (git-fileinfo->name info))
-		    (git-file-type-as-string old-perm new-perm)
-		    (git-rename-as-string info)))))
-
-(defun git-update-node-fileinfo (node info)
-  "Update the fileinfo of the specified node. The names are assumed to match already."
-  (let ((data (ewoc-data node)))
-    (setf
-     ;; preserve the marked flag
-     (git-fileinfo->marked info) (git-fileinfo->marked data)
-     (git-fileinfo->needs-update data) nil)
-    (when (not (equal info data))
-      (setf (git-fileinfo->needs-refresh info) t
-            (ewoc-data node) info))))
-
-(defun git-insert-info-list (status infolist files)
-  "Insert a sorted list of file infos in the status buffer, replacing existing ones if any."
-  (let* ((info (pop infolist))
-         (node (ewoc-nth status 0))
-         (name (and info (git-fileinfo->name info)))
-         remaining)
-    (while info
-      (let ((nodename (and node (git-fileinfo->name (ewoc-data node)))))
-        (while (and files (string-lessp (car files) name))
-          (push (pop files) remaining))
-        (when (and files (string-equal (car files) name))
-          (setq files (cdr files)))
-        (cond ((not nodename)
-               (setq node (ewoc-enter-last status info))
-               (setq info (pop infolist))
-               (setq name (and info (git-fileinfo->name info))))
-              ((string-lessp nodename name)
-               (setq node (ewoc-next status node)))
-              ((string-equal nodename name)
-               ;; preserve the marked flag
-               (git-update-node-fileinfo node info)
-               (setq info (pop infolist))
-               (setq name (and info (git-fileinfo->name info))))
-              (t
-               (setq node (ewoc-enter-before status node info))
-               (setq info (pop infolist))
-               (setq name (and info (git-fileinfo->name info)))))))
-    (nconc (nreverse remaining) files)))
-
-(defun git-run-diff-index (status files)
-  "Run git-diff-index on FILES and parse the results into STATUS.
-Return the list of files that haven't been handled."
-  (let (infolist)
-    (with-temp-buffer
-      (apply #'git-call-process t "diff-index" "-z" "-M" "HEAD" "--" files)
-      (goto-char (point-min))
-      (while (re-search-forward
-	      ":\\([0-7]\\{6\\}\\) \\([0-7]\\{6\\}\\) [0-9a-f]\\{40\\} [0-9a-f]\\{40\\} \\(\\([ADMUT]\\)\0\\([^\0]+\\)\\|\\([CR]\\)[0-9]*\0\\([^\0]+\\)\0\\([^\0]+\\)\\)\0"
-              nil t 1)
-        (let ((old-perm (string-to-number (match-string 1) 8))
-              (new-perm (string-to-number (match-string 2) 8))
-              (state (or (match-string 4) (match-string 6)))
-              (name (or (match-string 5) (match-string 7)))
-              (new-name (match-string 8)))
-          (if new-name  ; copy or rename
-              (if (eq ?C (string-to-char state))
-                  (push (git-create-fileinfo 'added new-name old-perm new-perm 'copy name) infolist)
-                (push (git-create-fileinfo 'deleted name 0 0 'rename new-name) infolist)
-                (push (git-create-fileinfo 'added new-name old-perm new-perm 'rename name) infolist))
-            (push (git-create-fileinfo (git-state-code state) name old-perm new-perm) infolist)))))
-    (setq infolist (sort (nreverse infolist)
-                         (lambda (info1 info2)
-                           (string-lessp (git-fileinfo->name info1)
-                                         (git-fileinfo->name info2)))))
-    (git-insert-info-list status infolist files)))
-
-(defun git-find-status-file (status file)
-  "Find a given file in the status ewoc and return its node."
-  (let ((node (ewoc-nth status 0)))
-    (while (and node (not (string= file (git-fileinfo->name (ewoc-data node)))))
-      (setq node (ewoc-next status node)))
-    node))
-
-(defun git-run-ls-files (status files default-state &rest options)
-  "Run git-ls-files on FILES and parse the results into STATUS.
-Return the list of files that haven't been handled."
-  (let (infolist)
-    (with-temp-buffer
-      (apply #'git-call-process t "ls-files" "-z" (append options (list "--") files))
-      (goto-char (point-min))
-      (while (re-search-forward "\\([^\0]*?\\)\\(/?\\)\0" nil t 1)
-        (let ((name (match-string 1)))
-          (push (git-create-fileinfo default-state name 0
-                                     (if (string-equal "/" (match-string 2)) (lsh ?\110 9) 0))
-                infolist))))
-    (setq infolist (nreverse infolist))  ;; assume it is sorted already
-    (git-insert-info-list status infolist files)))
-
-(defun git-run-ls-files-cached (status files default-state)
-  "Run git-ls-files -c on FILES and parse the results into STATUS.
-Return the list of files that haven't been handled."
-  (let (infolist)
-    (with-temp-buffer
-      (apply #'git-call-process t "ls-files" "-z" "-s" "-c" "--" files)
-      (goto-char (point-min))
-      (while (re-search-forward "\\([0-7]\\{6\\}\\) [0-9a-f]\\{40\\} 0\t\\([^\0]+\\)\0" nil t)
-	(let* ((new-perm (string-to-number (match-string 1) 8))
-	       (old-perm (if (eq default-state 'added) 0 new-perm))
-	       (name (match-string 2)))
-	  (push (git-create-fileinfo default-state name old-perm new-perm) infolist))))
-    (setq infolist (nreverse infolist))  ;; assume it is sorted already
-    (git-insert-info-list status infolist files)))
-
-(defun git-run-ls-unmerged (status files)
-  "Run git-ls-files -u on FILES and parse the results into STATUS."
-  (with-temp-buffer
-    (apply #'git-call-process t "ls-files" "-z" "-u" "--" files)
-    (goto-char (point-min))
-    (let (unmerged-files)
-      (while (re-search-forward "[0-7]\\{6\\} [0-9a-f]\\{40\\} [123]\t\\([^\0]+\\)\0" nil t)
-        (push (match-string 1) unmerged-files))
-      (setq unmerged-files (nreverse unmerged-files))  ;; assume it is sorted already
-      (git-set-filenames-state status unmerged-files 'unmerged))))
-
-(defun git-get-exclude-files ()
-  "Get the list of exclude files to pass to git-ls-files."
-  (let (files
-        (config (git-config "core.excludesfile")))
-    (when (file-readable-p ".git/info/exclude")
-      (push ".git/info/exclude" files))
-    (when (and config (file-readable-p config))
-      (push config files))
-    files))
-
-(defun git-run-ls-files-with-excludes (status files default-state &rest options)
-  "Run git-ls-files on FILES with appropriate --exclude-from options."
-  (let ((exclude-files (git-get-exclude-files)))
-    (apply #'git-run-ls-files status files default-state "--directory" "--no-empty-directory"
-           (concat "--exclude-per-directory=" git-per-dir-ignore-file)
-           (append options (mapcar (lambda (f) (concat "--exclude-from=" f)) exclude-files)))))
-
-(defun git-update-status-files (&optional files mark-files)
-  "Update the status of FILES from the index.
-The FILES list must be sorted."
-  (unless git-status (error "Not in git-status buffer."))
-  ;; set the needs-update flag on existing files
-  (if files
-      (git-status-filenames-map
-       git-status (lambda (info) (setf (git-fileinfo->needs-update info) t)) files)
-    (ewoc-map (lambda (info) (setf (git-fileinfo->needs-update info) t) nil) git-status)
-    (git-call-process nil "update-index" "--refresh")
-    (when git-show-uptodate
-      (git-run-ls-files-cached git-status nil 'uptodate)))
-  (let ((remaining-files
-          (if (git-empty-db-p) ; we need some special handling for an empty db
-	      (git-run-ls-files-cached git-status files 'added)
-            (git-run-diff-index git-status files))))
-    (git-run-ls-unmerged git-status files)
-    (when (or remaining-files (and git-show-unknown (not files)))
-      (setq remaining-files (git-run-ls-files-with-excludes git-status remaining-files 'unknown "-o")))
-    (when (or remaining-files (and git-show-ignored (not files)))
-      (setq remaining-files (git-run-ls-files-with-excludes git-status remaining-files 'ignored "-o" "-i")))
-    (unless files
-      (setq remaining-files (git-get-filenames (ewoc-collect git-status #'git-fileinfo->needs-update))))
-    (when remaining-files
-      (setq remaining-files (git-run-ls-files-cached git-status remaining-files 'uptodate)))
-    (git-set-filenames-state git-status remaining-files nil)
-    (when mark-files (git-mark-files git-status files))
-    (git-refresh-files)
-    (git-refresh-ewoc-hf git-status)))
-
-(defun git-mark-files (status files)
-  "Mark all the specified FILES, and unmark the others."
-  (let ((file (and files (pop files)))
-        (node (ewoc-nth status 0)))
-    (while node
-      (let ((info (ewoc-data node)))
-        (if (and file (string-equal (git-fileinfo->name info) file))
-            (progn
-              (unless (git-fileinfo->marked info)
-                (setf (git-fileinfo->marked info) t)
-                (setf (git-fileinfo->needs-refresh info) t))
-              (setq file (pop files))
-              (setq node (ewoc-next status node)))
-          (when (git-fileinfo->marked info)
-            (setf (git-fileinfo->marked info) nil)
-            (setf (git-fileinfo->needs-refresh info) t))
-          (if (and file (string-lessp file (git-fileinfo->name info)))
-              (setq file (pop files))
-            (setq node (ewoc-next status node))))))))
-
-(defun git-marked-files ()
-  "Return a list of all marked files, or if none a list containing just the file at cursor position."
-  (unless git-status (error "Not in git-status buffer."))
-  (or (ewoc-collect git-status (lambda (info) (git-fileinfo->marked info)))
-      (list (ewoc-data (ewoc-locate git-status)))))
-
-(defun git-marked-files-state (&rest states)
-  "Return a sorted list of marked files that are in the specified states."
-  (let ((files (git-marked-files))
-        result)
-    (dolist (info files)
-      (when (memq (git-fileinfo->state info) states)
-        (push info result)))
-    (nreverse result)))
-
-(defun git-refresh-files ()
-  "Refresh all files that need it and clear the needs-refresh flag."
-  (unless git-status (error "Not in git-status buffer."))
-  (ewoc-map
-   (lambda (info)
-     (let ((refresh (git-fileinfo->needs-refresh info)))
-       (setf (git-fileinfo->needs-refresh info) nil)
-       refresh))
-   git-status)
-  ; move back to goal column
-  (when goal-column (move-to-column goal-column)))
-
-(defun git-refresh-ewoc-hf (status)
-  "Refresh the ewoc header and footer."
-  (let ((branch (git-symbolic-ref "HEAD"))
-        (head (if (git-empty-db-p) "Nothing committed yet"
-                (git-get-commit-description "HEAD")))
-        (merge-heads (git-get-merge-heads)))
-    (ewoc-set-hf status
-                 (format "Directory:  %s\nBranch:     %s\nHead:       %s%s\n"
-                         default-directory
-                         (if branch
-                             (if (string-match "^refs/heads/" branch)
-                                 (substring branch (match-end 0))
-                               branch)
-                           "none (detached HEAD)")
-                         head
-                         (if merge-heads
-                             (concat "\nMerging:    "
-                                     (mapconcat (lambda (str) (git-get-commit-description str)) merge-heads "\n            "))
-                           ""))
-                 (if (ewoc-nth status 0) "" "    No changes."))))
-
-(defun git-get-filenames (files)
-  (mapcar (lambda (info) (git-fileinfo->name info)) files))
-
-(defun git-update-index (index-file files)
-  "Run git-update-index on a list of files."
-  (let ((process-environment (append (and index-file (list (concat "GIT_INDEX_FILE=" index-file)))
-                                     process-environment))
-        added deleted modified)
-    (dolist (info files)
-      (case (git-fileinfo->state info)
-        ('added (push info added))
-        ('deleted (push info deleted))
-        ('modified (push info modified))))
-    (and
-     (or (not added) (apply #'git-call-process-display-error "update-index" "--add" "--" (git-get-filenames added)))
-     (or (not deleted) (apply #'git-call-process-display-error "update-index" "--remove" "--" (git-get-filenames deleted)))
-     (or (not modified) (apply #'git-call-process-display-error "update-index" "--" (git-get-filenames modified))))))
-
-(defun git-run-pre-commit-hook ()
-  "Run the pre-commit hook if any."
-  (unless git-status (error "Not in git-status buffer."))
-  (let ((files (git-marked-files-state 'added 'deleted 'modified)))
-    (or (not files)
-        (not (file-executable-p ".git/hooks/pre-commit"))
-        (let ((index-file (make-temp-file "gitidx")))
-          (unwind-protect
-            (let ((head-tree (unless (git-empty-db-p) (git-rev-parse "HEAD^{tree}"))))
-              (git-read-tree head-tree index-file)
-              (git-update-index index-file files)
-              (git-run-hook "pre-commit" `(("GIT_INDEX_FILE" . ,index-file))))
-          (delete-file index-file))))))
-
-(defun git-do-commit ()
-  "Perform the actual commit using the current buffer as log message."
-  (interactive)
-  (let ((buffer (current-buffer))
-        (index-file (make-temp-file "gitidx")))
-    (with-current-buffer log-edit-parent-buffer
-      (if (git-marked-files-state 'unmerged)
-          (message "You cannot commit unmerged files, resolve them first.")
-        (unwind-protect
-            (let ((files (git-marked-files-state 'added 'deleted 'modified))
-                  head tree head-tree)
-              (unless (git-empty-db-p)
-                (setq head (git-rev-parse "HEAD")
-                      head-tree (git-rev-parse "HEAD^{tree}")))
-              (message "Running git commit...")
-              (when
-                  (and
-                   (git-read-tree head-tree index-file)
-                   (git-update-index nil files)         ;update both the default index
-                   (git-update-index index-file files)  ;and the temporary one
-                   (setq tree (git-write-tree index-file)))
-                (if (or (not (string-equal tree head-tree))
-                        (yes-or-no-p "The tree was not modified, do you really want to perform an empty commit? "))
-                    (let ((commit (git-commit-tree buffer tree head)))
-                      (when commit
-                        (condition-case nil (delete-file ".git/MERGE_HEAD") (error nil))
-                        (condition-case nil (delete-file ".git/MERGE_MSG") (error nil))
-                        (with-current-buffer buffer (erase-buffer))
-                        (git-update-status-files (git-get-filenames files))
-                        (git-call-process nil "rerere")
-                        (git-call-process nil "gc" "--auto")
-                        (message "Committed %s." commit)
-                        (git-run-hook "post-commit" nil)))
-                  (message "Commit aborted."))))
-          (delete-file index-file))))))
-
-
-;;;; Interactive functions
-;;;; ------------------------------------------------------------
-
-(defun git-mark-file ()
-  "Mark the file that the cursor is on and move to the next one."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (let* ((pos (ewoc-locate git-status))
-         (info (ewoc-data pos)))
-    (setf (git-fileinfo->marked info) t)
-    (ewoc-invalidate git-status pos)
-    (ewoc-goto-next git-status 1)))
-
-(defun git-unmark-file ()
-  "Unmark the file that the cursor is on and move to the next one."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (let* ((pos (ewoc-locate git-status))
-         (info (ewoc-data pos)))
-    (setf (git-fileinfo->marked info) nil)
-    (ewoc-invalidate git-status pos)
-    (ewoc-goto-next git-status 1)))
-
-(defun git-unmark-file-up ()
-  "Unmark the file that the cursor is on and move to the previous one."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (let* ((pos (ewoc-locate git-status))
-         (info (ewoc-data pos)))
-    (setf (git-fileinfo->marked info) nil)
-    (ewoc-invalidate git-status pos)
-    (ewoc-goto-prev git-status 1)))
-
-(defun git-mark-all ()
-  "Mark all files."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (ewoc-map (lambda (info) (unless (git-fileinfo->marked info)
-                             (setf (git-fileinfo->marked info) t))) git-status)
-  ; move back to goal column after invalidate
-  (when goal-column (move-to-column goal-column)))
-
-(defun git-unmark-all ()
-  "Unmark all files."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (ewoc-map (lambda (info) (when (git-fileinfo->marked info)
-                             (setf (git-fileinfo->marked info) nil)
-                             t)) git-status)
-  ; move back to goal column after invalidate
-  (when goal-column (move-to-column goal-column)))
-
-(defun git-toggle-all-marks ()
-  "Toggle all file marks."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (ewoc-map (lambda (info) (setf (git-fileinfo->marked info) (not (git-fileinfo->marked info))) t) git-status)
-  ; move back to goal column after invalidate
-  (when goal-column (move-to-column goal-column)))
-
-(defun git-next-file (&optional n)
-  "Move the selection down N files."
-  (interactive "p")
-  (unless git-status (error "Not in git-status buffer."))
-  (ewoc-goto-next git-status n))
-
-(defun git-prev-file (&optional n)
-  "Move the selection up N files."
-  (interactive "p")
-  (unless git-status (error "Not in git-status buffer."))
-  (ewoc-goto-prev git-status n))
-
-(defun git-next-unmerged-file (&optional n)
-  "Move the selection down N unmerged files."
-  (interactive "p")
-  (unless git-status (error "Not in git-status buffer."))
-  (let* ((last (ewoc-locate git-status))
-         (node (ewoc-next git-status last)))
-    (while (and node (> n 0))
-      (when (eq 'unmerged (git-fileinfo->state (ewoc-data node)))
-        (setq n (1- n))
-        (setq last node))
-      (setq node (ewoc-next git-status node)))
-    (ewoc-goto-node git-status last)))
-
-(defun git-prev-unmerged-file (&optional n)
-  "Move the selection up N unmerged files."
-  (interactive "p")
-  (unless git-status (error "Not in git-status buffer."))
-  (let* ((last (ewoc-locate git-status))
-         (node (ewoc-prev git-status last)))
-    (while (and node (> n 0))
-      (when (eq 'unmerged (git-fileinfo->state (ewoc-data node)))
-        (setq n (1- n))
-        (setq last node))
-      (setq node (ewoc-prev git-status node)))
-    (ewoc-goto-node git-status last)))
-
-(defun git-insert-file (file)
-  "Insert file(s) into the git-status buffer."
-  (interactive "fInsert file: ")
-  (git-update-status-files (list (file-relative-name file))))
-
-(defun git-add-file ()
-  "Add marked file(s) to the index cache."
-  (interactive)
-  (let ((files (git-get-filenames (git-marked-files-state 'unknown 'ignored 'unmerged))))
-    ;; FIXME: add support for directories
-    (unless files
-      (push (file-relative-name (read-file-name "File to add: " nil nil t)) files))
-    (when (apply 'git-call-process-display-error "update-index" "--add" "--" files)
-      (git-update-status-files files)
-      (git-success-message "Added" files))))
-
-(defun git-ignore-file ()
-  "Add marked file(s) to the ignore list."
-  (interactive)
-  (let ((files (git-get-filenames (git-marked-files-state 'unknown))))
-    (unless files
-      (push (file-relative-name (read-file-name "File to ignore: " nil nil t)) files))
-    (dolist (f files) (git-append-to-ignore f))
-    (git-update-status-files files)
-    (git-success-message "Ignored" files)))
-
-(defun git-remove-file ()
-  "Remove the marked file(s)."
-  (interactive)
-  (let ((files (git-get-filenames (git-marked-files-state 'added 'modified 'unknown 'uptodate 'ignored))))
-    (unless files
-      (push (file-relative-name (read-file-name "File to remove: " nil nil t)) files))
-    (if (yes-or-no-p
-         (if (cdr files)
-             (format "Remove %d files? " (length files))
-           (format "Remove %s? " (car files))))
-        (progn
-          (dolist (name files)
-            (ignore-errors
-              (if (file-directory-p name)
-                  (delete-directory name)
-                (delete-file name))))
-          (when (apply 'git-call-process-display-error "update-index" "--remove" "--" files)
-            (git-update-status-files files)
-            (git-success-message "Removed" files)))
-      (message "Aborting"))))
-
-(defun git-revert-file ()
-  "Revert changes to the marked file(s)."
-  (interactive)
-  (let ((files (git-marked-files-state 'added 'deleted 'modified 'unmerged))
-        added modified)
-    (when (and files
-               (yes-or-no-p
-                (if (cdr files)
-                    (format "Revert %d files? " (length files))
-                  (format "Revert %s? " (git-fileinfo->name (car files))))))
-      (dolist (info files)
-        (case (git-fileinfo->state info)
-          ('added (push (git-fileinfo->name info) added))
-          ('deleted (push (git-fileinfo->name info) modified))
-          ('unmerged (push (git-fileinfo->name info) modified))
-          ('modified (push (git-fileinfo->name info) modified))))
-      ;; check if a buffer contains one of the files and isn't saved
-      (dolist (file modified)
-        (let ((buffer (get-file-buffer file)))
-          (when (and buffer (buffer-modified-p buffer))
-            (error "Buffer %s is modified. Please kill or save modified buffers before reverting." (buffer-name buffer)))))
-      (let ((ok (and
-                 (or (not added)
-                     (apply 'git-call-process-display-error "update-index" "--force-remove" "--" added))
-                 (or (not modified)
-                     (apply 'git-call-process-display-error "checkout" "HEAD" modified))))
-            (names (git-get-filenames files)))
-        (git-update-status-files names)
-        (when ok
-          (dolist (file modified)
-            (let ((buffer (get-file-buffer file)))
-              (when buffer (with-current-buffer buffer (revert-buffer t t t)))))
-          (git-success-message "Reverted" names))))))
-
-(defun git-remove-handled ()
-  "Remove handled files from the status list."
-  (interactive)
-  (ewoc-filter git-status
-               (lambda (info)
-                 (case (git-fileinfo->state info)
-                   ('ignored git-show-ignored)
-                   ('uptodate git-show-uptodate)
-                   ('unknown git-show-unknown)
-                   (t t))))
-  (unless (ewoc-nth git-status 0)  ; refresh header if list is empty
-    (git-refresh-ewoc-hf git-status)))
-
-(defun git-toggle-show-uptodate ()
-  "Toogle the option for showing up-to-date files."
-  (interactive)
-  (if (setq git-show-uptodate (not git-show-uptodate))
-      (git-refresh-status)
-    (git-remove-handled)))
-
-(defun git-toggle-show-ignored ()
-  "Toogle the option for showing ignored files."
-  (interactive)
-  (if (setq git-show-ignored (not git-show-ignored))
-      (progn
-        (message "Inserting ignored files...")
-        (git-run-ls-files-with-excludes git-status nil 'ignored "-o" "-i")
-        (git-refresh-files)
-        (git-refresh-ewoc-hf git-status)
-        (message "Inserting ignored files...done"))
-    (git-remove-handled)))
-
-(defun git-toggle-show-unknown ()
-  "Toogle the option for showing unknown files."
-  (interactive)
-  (if (setq git-show-unknown (not git-show-unknown))
-      (progn
-        (message "Inserting unknown files...")
-        (git-run-ls-files-with-excludes git-status nil 'unknown "-o")
-        (git-refresh-files)
-        (git-refresh-ewoc-hf git-status)
-        (message "Inserting unknown files...done"))
-    (git-remove-handled)))
-
-(defun git-expand-directory (info)
-  "Expand the directory represented by INFO to list its files."
-  (when (eq (lsh (git-fileinfo->new-perm info) -9) ?\110)
-    (let ((dir (git-fileinfo->name info)))
-      (git-set-filenames-state git-status (list dir) nil)
-      (git-run-ls-files-with-excludes git-status (list (concat dir "/")) 'unknown "-o")
-      (git-refresh-files)
-      (git-refresh-ewoc-hf git-status)
-      t)))
-
-(defun git-setup-diff-buffer (buffer)
-  "Setup a buffer for displaying a diff."
-  (let ((dir default-directory))
-    (with-current-buffer buffer
-      (diff-mode)
-      (goto-char (point-min))
-      (setq default-directory dir)
-      (setq buffer-read-only t)))
-  (display-buffer buffer)
-  ; shrink window only if it displays the status buffer
-  (when (eq (window-buffer) (current-buffer))
-    (shrink-window-if-larger-than-buffer)))
-
-(defun git-diff-file ()
-  "Diff the marked file(s) against HEAD."
-  (interactive)
-  (let ((files (git-marked-files)))
-    (git-setup-diff-buffer
-     (apply #'git-run-command-buffer "*git-diff*" "diff-index" "-p" "-M" "HEAD" "--" (git-get-filenames files)))))
-
-(defun git-diff-file-merge-head (arg)
-  "Diff the marked file(s) against the first merge head (or the nth one with a numeric prefix)."
-  (interactive "p")
-  (let ((files (git-marked-files))
-        (merge-heads (git-get-merge-heads)))
-    (unless merge-heads (error "No merge in progress"))
-    (git-setup-diff-buffer
-     (apply #'git-run-command-buffer "*git-diff*" "diff-index" "-p" "-M"
-            (or (nth (1- arg) merge-heads) "HEAD") "--" (git-get-filenames files)))))
-
-(defun git-diff-unmerged-file (stage)
-  "Diff the marked unmerged file(s) against the specified stage."
-  (let ((files (git-marked-files)))
-    (git-setup-diff-buffer
-     (apply #'git-run-command-buffer "*git-diff*" "diff-files" "-p" stage "--" (git-get-filenames files)))))
-
-(defun git-diff-file-base ()
-  "Diff the marked unmerged file(s) against the common base file."
-  (interactive)
-  (git-diff-unmerged-file "-1"))
-
-(defun git-diff-file-mine ()
-  "Diff the marked unmerged file(s) against my pre-merge version."
-  (interactive)
-  (git-diff-unmerged-file "-2"))
-
-(defun git-diff-file-other ()
-  "Diff the marked unmerged file(s) against the other's pre-merge version."
-  (interactive)
-  (git-diff-unmerged-file "-3"))
-
-(defun git-diff-file-combined ()
-  "Do a combined diff of the marked unmerged file(s)."
-  (interactive)
-  (git-diff-unmerged-file "-c"))
-
-(defun git-diff-file-idiff ()
-  "Perform an interactive diff on the current file."
-  (interactive)
-  (let ((files (git-marked-files-state 'added 'deleted 'modified)))
-    (unless (eq 1 (length files))
-      (error "Cannot perform an interactive diff on multiple files."))
-    (let* ((filename (car (git-get-filenames files)))
-           (buff1 (find-file-noselect filename))
-           (buff2 (git-run-command-buffer (concat filename ".~HEAD~") "cat-file" "blob" (concat "HEAD:" filename))))
-      (ediff-buffers buff1 buff2))))
-
-(defun git-log-file ()
-  "Display a log of changes to the marked file(s)."
-  (interactive)
-  (let* ((files (git-marked-files))
-         (coding-system-for-read git-commits-coding-system)
-         (buffer (apply #'git-run-command-buffer "*git-log*" "rev-list" "--pretty" "HEAD" "--" (git-get-filenames files))))
-    (with-current-buffer buffer
-      ; (git-log-mode)  FIXME: implement log mode
-      (goto-char (point-min))
-      (setq buffer-read-only t))
-    (display-buffer buffer)))
-
-(defun git-log-edit-files ()
-  "Return a list of marked files for use in the log-edit buffer."
-  (with-current-buffer log-edit-parent-buffer
-    (git-get-filenames (git-marked-files-state 'added 'deleted 'modified))))
-
-(defun git-log-edit-diff ()
-  "Run a diff of the current files being committed from a log-edit buffer."
-  (with-current-buffer log-edit-parent-buffer
-    (git-diff-file)))
-
-(defun git-append-sign-off (name email)
-  "Append a Signed-off-by entry to the current buffer, avoiding duplicates."
-  (let ((sign-off (format "Signed-off-by: %s <%s>" name email))
-        (case-fold-search t))
-    (goto-char (point-min))
-    (unless (re-search-forward (concat "^" (regexp-quote sign-off)) nil t)
-      (goto-char (point-min))
-      (unless (re-search-forward "^Signed-off-by: " nil t)
-        (setq sign-off (concat "\n" sign-off)))
-      (goto-char (point-max))
-      (insert sign-off "\n"))))
-
-(defun git-setup-log-buffer (buffer &optional merge-heads author-name author-email subject date msg)
-  "Setup the log buffer for a commit."
-  (unless git-status (error "Not in git-status buffer."))
-  (let ((dir default-directory)
-        (committer-name (git-get-committer-name))
-        (committer-email (git-get-committer-email))
-        (sign-off git-append-signed-off-by))
-    (with-current-buffer buffer
-      (cd dir)
-      (erase-buffer)
-      (insert
-       (propertize
-        (format "Author: %s <%s>\n%s%s"
-                (or author-name committer-name)
-                (or author-email committer-email)
-                (if date (format "Date: %s\n" date) "")
-                (if merge-heads
-                    (format "Merge: %s\n"
-                            (mapconcat 'identity merge-heads " "))
-                  ""))
-        'face 'git-header-face)
-       (propertize git-log-msg-separator 'face 'git-separator-face)
-       "\n")
-      (when subject (insert subject "\n\n"))
-      (cond (msg (insert msg "\n"))
-            ((file-readable-p ".git/rebase-apply/msg")
-             (insert-file-contents ".git/rebase-apply/msg"))
-            ((file-readable-p ".git/MERGE_MSG")
-             (insert-file-contents ".git/MERGE_MSG")))
-      ; delete empty lines at end
-      (goto-char (point-min))
-      (when (re-search-forward "\n+\\'" nil t)
-        (replace-match "\n" t t))
-      (when sign-off (git-append-sign-off committer-name committer-email)))
-    buffer))
-
-(define-derived-mode git-log-edit-mode log-edit-mode "Git-Log-Edit"
-  "Major mode for editing git log messages.
-
-Set up git-specific `font-lock-keywords' for `log-edit-mode'."
-  (set (make-local-variable 'font-lock-defaults)
-       '(git-log-edit-font-lock-keywords t t)))
-
-(defun git-commit-file ()
-  "Commit the marked file(s), asking for a commit message."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (when (git-run-pre-commit-hook)
-    (let ((buffer (get-buffer-create "*git-commit*"))
-          (coding-system (git-get-commits-coding-system))
-          author-name author-email subject date)
-      (when (eq 0 (buffer-size buffer))
-        (when (file-readable-p ".git/rebase-apply/info")
-          (with-temp-buffer
-            (insert-file-contents ".git/rebase-apply/info")
-            (goto-char (point-min))
-            (when (re-search-forward "^Author: \\(.*\\)\nEmail: \\(.*\\)$" nil t)
-              (setq author-name (match-string 1))
-              (setq author-email (match-string 2)))
-            (goto-char (point-min))
-            (when (re-search-forward "^Subject: \\(.*\\)$" nil t)
-              (setq subject (match-string 1)))
-            (goto-char (point-min))
-            (when (re-search-forward "^Date: \\(.*\\)$" nil t)
-              (setq date (match-string 1)))))
-        (git-setup-log-buffer buffer (git-get-merge-heads) author-name author-email subject date))
-      (if (boundp 'log-edit-diff-function)
-	  (log-edit 'git-do-commit nil '((log-edit-listfun . git-log-edit-files)
-					 (log-edit-diff-function . git-log-edit-diff)) buffer 'git-log-edit-mode)
-	(log-edit 'git-do-commit nil 'git-log-edit-files buffer
-                  'git-log-edit-mode))
-      (setq paragraph-separate (concat (regexp-quote git-log-msg-separator) "$\\|Author: \\|Date: \\|Merge: \\|Signed-off-by: \\|\f\\|[ 	]*$"))
-      (setq buffer-file-coding-system coding-system)
-      (re-search-forward (regexp-quote (concat git-log-msg-separator "\n")) nil t))))
-
-(defun git-setup-commit-buffer (commit)
-  "Setup the commit buffer with the contents of COMMIT."
-  (let (parents author-name author-email subject date msg)
-    (with-temp-buffer
-      (let ((coding-system (git-get-logoutput-coding-system)))
-        (git-call-process t "log" "-1" "--pretty=medium" "--abbrev=40" commit)
-        (goto-char (point-min))
-        (when (re-search-forward "^Merge: *\\(.*\\)$" nil t)
-          (setq parents (cdr (split-string (match-string 1) " +"))))
-        (when (re-search-forward "^Author: *\\(.*\\) <\\(.*\\)>$" nil t)
-          (setq author-name (match-string 1))
-          (setq author-email (match-string 2)))
-        (when (re-search-forward "^Date: *\\(.*\\)$" nil t)
-          (setq date (match-string 1)))
-        (while (re-search-forward "^    \\(.*\\)$" nil t)
-          (push (match-string 1) msg))
-        (setq msg (nreverse msg))
-        (setq subject (pop msg))
-        (while (and msg (zerop (length (car msg))) (pop msg)))))
-    (git-setup-log-buffer (get-buffer-create "*git-commit*")
-                          parents author-name author-email subject date
-                          (mapconcat #'identity msg "\n"))))
-
-(defun git-get-commit-files (commit)
-  "Retrieve a sorted list of files modified by COMMIT."
-  (let (files)
-    (with-temp-buffer
-      (git-call-process t "diff-tree" "-m" "-r" "-z" "--name-only" "--no-commit-id" "--root" commit)
-      (goto-char (point-min))
-      (while (re-search-forward "\\([^\0]*\\)\0" nil t 1)
-        (push (match-string 1) files)))
-    (sort files #'string-lessp)))
-
-(defun git-read-commit-name (prompt &optional default)
-  "Ask for a commit name, with completion for local branch, remote branch and tag."
-  (completing-read prompt
-                   (list* "HEAD" "ORIG_HEAD" "FETCH_HEAD" (mapcar #'car (git-for-each-ref)))
-		   nil nil nil nil default))
-
-(defun git-checkout (branch &optional merge)
-  "Checkout a branch, tag, or any commit.
-Use a prefix arg if git should merge while checking out."
-  (interactive
-   (list (git-read-commit-name "Checkout: ")
-         current-prefix-arg))
-  (unless git-status (error "Not in git-status buffer."))
-  (let ((args (list branch "--")))
-    (when merge (push "-m" args))
-    (when (apply #'git-call-process-display-error "checkout" args)
-      (git-update-status-files))))
-
-(defun git-branch (branch)
-  "Create a branch from the current HEAD and switch to it."
-  (interactive (list (git-read-commit-name "Branch: ")))
-  (unless git-status (error "Not in git-status buffer."))
-  (if (git-rev-parse (concat "refs/heads/" branch))
-      (if (yes-or-no-p (format "Branch %s already exists, replace it? " branch))
-          (and (git-call-process-display-error "branch" "-f" branch)
-               (git-call-process-display-error "checkout" branch))
-        (message "Canceled."))
-    (git-call-process-display-error "checkout" "-b" branch))
-    (git-refresh-ewoc-hf git-status))
-
-(defun git-amend-commit ()
-  "Undo the last commit on HEAD, and set things up to commit an
-amended version of it."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (when (git-empty-db-p) (error "No commit to amend."))
-  (let* ((commit (git-rev-parse "HEAD"))
-         (files (git-get-commit-files commit)))
-    (when (if (git-rev-parse "HEAD^")
-              (git-call-process-display-error "reset" "--soft" "HEAD^")
-            (and (git-update-ref "ORIG_HEAD" commit)
-                 (git-update-ref "HEAD" nil commit)))
-      (git-update-status-files files t)
-      (git-setup-commit-buffer commit)
-      (git-commit-file))))
-
-(defun git-cherry-pick-commit (arg)
-  "Cherry-pick a commit."
-  (interactive (list (git-read-commit-name "Cherry-pick commit: ")))
-  (unless git-status (error "Not in git-status buffer."))
-  (let ((commit (git-rev-parse (concat arg "^0"))))
-    (unless commit (error "Not a valid commit '%s'." arg))
-    (when (git-rev-parse (concat commit "^2"))
-      (error "Cannot cherry-pick a merge commit."))
-    (let ((files (git-get-commit-files commit))
-          (ok (git-call-process-display-error "cherry-pick" "-n" commit)))
-      (git-update-status-files files ok)
-      (with-current-buffer (git-setup-commit-buffer commit)
-        (goto-char (point-min))
-        (if (re-search-forward "^\n*Signed-off-by:" nil t 1)
-            (goto-char (match-beginning 0))
-          (goto-char (point-max)))
-        (insert "(cherry picked from commit " commit ")\n"))
-      (when ok (git-commit-file)))))
-
-(defun git-revert-commit (arg)
-  "Revert a commit."
-  (interactive (list (git-read-commit-name "Revert commit: ")))
-  (unless git-status (error "Not in git-status buffer."))
-  (let ((commit (git-rev-parse (concat arg "^0"))))
-    (unless commit (error "Not a valid commit '%s'." arg))
-    (when (git-rev-parse (concat commit "^2"))
-      (error "Cannot revert a merge commit."))
-    (let ((files (git-get-commit-files commit))
-          (subject (git-get-commit-description commit))
-          (ok (git-call-process-display-error "revert" "-n" commit)))
-      (git-update-status-files files ok)
-      (when (string-match "^[0-9a-f]+ - \\(.*\\)$" subject)
-        (setq subject (match-string 1 subject)))
-      (git-setup-log-buffer (get-buffer-create "*git-commit*")
-                            (git-get-merge-heads) nil nil (format "Revert \"%s\"" subject) nil
-                            (format "This reverts commit %s.\n" commit))
-      (when ok (git-commit-file)))))
-
-(defun git-find-file ()
-  "Visit the current file in its own buffer."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (let ((info (ewoc-data (ewoc-locate git-status))))
-    (unless (git-expand-directory info)
-      (find-file (git-fileinfo->name info))
-      (when (eq 'unmerged (git-fileinfo->state info))
-        (smerge-mode 1)))))
-
-(defun git-find-file-other-window ()
-  "Visit the current file in its own buffer in another window."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (let ((info (ewoc-data (ewoc-locate git-status))))
-    (find-file-other-window (git-fileinfo->name info))
-    (when (eq 'unmerged (git-fileinfo->state info))
-      (smerge-mode))))
-
-(defun git-find-file-imerge ()
-  "Visit the current file in interactive merge mode."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (let ((info (ewoc-data (ewoc-locate git-status))))
-    (find-file (git-fileinfo->name info))
-    (smerge-ediff)))
-
-(defun git-view-file ()
-  "View the current file in its own buffer."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (let ((info (ewoc-data (ewoc-locate git-status))))
-    (view-file (git-fileinfo->name info))))
-
-(defun git-refresh-status ()
-  "Refresh the git status buffer."
-  (interactive)
-  (unless git-status (error "Not in git-status buffer."))
-  (message "Refreshing git status...")
-  (git-update-status-files)
-  (message "Refreshing git status...done"))
-
-(defun git-status-quit ()
-  "Quit git-status mode."
-  (interactive)
-  (bury-buffer))
-
-;;;; Major Mode
-;;;; ------------------------------------------------------------
-
-(defvar git-status-mode-hook nil
-  "Run after `git-status-mode' is setup.")
-
-(defvar git-status-mode-map nil
-  "Keymap for git major mode.")
-
-(defvar git-status nil
-  "List of all files managed by the git-status mode.")
-
-(unless git-status-mode-map
-  (let ((map (make-keymap))
-        (commit-map (make-sparse-keymap))
-        (diff-map (make-sparse-keymap))
-        (toggle-map (make-sparse-keymap)))
-    (suppress-keymap map)
-    (define-key map "?"   'git-help)
-    (define-key map "h"   'git-help)
-    (define-key map " "   'git-next-file)
-    (define-key map "a"   'git-add-file)
-    (define-key map "c"   'git-commit-file)
-    (define-key map "\C-c" commit-map)
-    (define-key map "d"    diff-map)
-    (define-key map "="   'git-diff-file)
-    (define-key map "f"   'git-find-file)
-    (define-key map "\r"  'git-find-file)
-    (define-key map "g"   'git-refresh-status)
-    (define-key map "i"   'git-ignore-file)
-    (define-key map "I"   'git-insert-file)
-    (define-key map "l"   'git-log-file)
-    (define-key map "m"   'git-mark-file)
-    (define-key map "M"   'git-mark-all)
-    (define-key map "n"   'git-next-file)
-    (define-key map "N"   'git-next-unmerged-file)
-    (define-key map "o"   'git-find-file-other-window)
-    (define-key map "p"   'git-prev-file)
-    (define-key map "P"   'git-prev-unmerged-file)
-    (define-key map "q"   'git-status-quit)
-    (define-key map "r"   'git-remove-file)
-    (define-key map "t"    toggle-map)
-    (define-key map "T"   'git-toggle-all-marks)
-    (define-key map "u"   'git-unmark-file)
-    (define-key map "U"   'git-revert-file)
-    (define-key map "v"   'git-view-file)
-    (define-key map "x"   'git-remove-handled)
-    (define-key map "\C-?" 'git-unmark-file-up)
-    (define-key map "\M-\C-?" 'git-unmark-all)
-    ; the commit submap
-    (define-key commit-map "\C-a" 'git-amend-commit)
-    (define-key commit-map "\C-b" 'git-branch)
-    (define-key commit-map "\C-o" 'git-checkout)
-    (define-key commit-map "\C-p" 'git-cherry-pick-commit)
-    (define-key commit-map "\C-v" 'git-revert-commit)
-    ; the diff submap
-    (define-key diff-map "b" 'git-diff-file-base)
-    (define-key diff-map "c" 'git-diff-file-combined)
-    (define-key diff-map "=" 'git-diff-file)
-    (define-key diff-map "e" 'git-diff-file-idiff)
-    (define-key diff-map "E" 'git-find-file-imerge)
-    (define-key diff-map "h" 'git-diff-file-merge-head)
-    (define-key diff-map "m" 'git-diff-file-mine)
-    (define-key diff-map "o" 'git-diff-file-other)
-    ; the toggle submap
-    (define-key toggle-map "u" 'git-toggle-show-uptodate)
-    (define-key toggle-map "i" 'git-toggle-show-ignored)
-    (define-key toggle-map "k" 'git-toggle-show-unknown)
-    (define-key toggle-map "m" 'git-toggle-all-marks)
-    (setq git-status-mode-map map))
-  (easy-menu-define git-menu git-status-mode-map
-    "Git Menu"
-    `("Git"
-      ["Refresh" git-refresh-status t]
-      ["Commit" git-commit-file t]
-      ["Checkout..." git-checkout t]
-      ["New Branch..." git-branch t]
-      ["Cherry-pick Commit..." git-cherry-pick-commit t]
-      ["Revert Commit..." git-revert-commit t]
-      ("Merge"
-	["Next Unmerged File" git-next-unmerged-file t]
-	["Prev Unmerged File" git-prev-unmerged-file t]
-	["Interactive Merge File" git-find-file-imerge t]
-	["Diff Against Common Base File" git-diff-file-base t]
-	["Diff Combined" git-diff-file-combined t]
-	["Diff Against Merge Head" git-diff-file-merge-head t]
-	["Diff Against Mine" git-diff-file-mine t]
-	["Diff Against Other" git-diff-file-other t])
-      "--------"
-      ["Add File" git-add-file t]
-      ["Revert File" git-revert-file t]
-      ["Ignore File" git-ignore-file t]
-      ["Remove File" git-remove-file t]
-      ["Insert File" git-insert-file t]
-      "--------"
-      ["Find File" git-find-file t]
-      ["View File" git-view-file t]
-      ["Diff File" git-diff-file t]
-      ["Interactive Diff File" git-diff-file-idiff t]
-      ["Log" git-log-file t]
-      "--------"
-      ["Mark" git-mark-file t]
-      ["Mark All" git-mark-all t]
-      ["Unmark" git-unmark-file t]
-      ["Unmark All" git-unmark-all t]
-      ["Toggle All Marks" git-toggle-all-marks t]
-      ["Hide Handled Files" git-remove-handled t]
-      "--------"
-      ["Show Uptodate Files" git-toggle-show-uptodate :style toggle :selected git-show-uptodate]
-      ["Show Ignored Files" git-toggle-show-ignored :style toggle :selected git-show-ignored]
-      ["Show Unknown Files" git-toggle-show-unknown :style toggle :selected git-show-unknown]
-      "--------"
-      ["Quit" git-status-quit t])))
-
-
-;; git mode should only run in the *git status* buffer
-(put 'git-status-mode 'mode-class 'special)
-
-(defun git-status-mode ()
-  "Major mode for interacting with Git.
-Commands:
-\\{git-status-mode-map}"
-  (kill-all-local-variables)
-  (buffer-disable-undo)
-  (setq mode-name "git status"
-        major-mode 'git-status-mode
-        goal-column 17
-        buffer-read-only t)
-  (use-local-map git-status-mode-map)
-  (let ((buffer-read-only nil))
-    (erase-buffer)
-  (let ((status (ewoc-create 'git-fileinfo-prettyprint "" "")))
-    (set (make-local-variable 'git-status) status))
-  (set (make-local-variable 'list-buffers-directory) default-directory)
-  (make-local-variable 'git-show-uptodate)
-  (make-local-variable 'git-show-ignored)
-  (make-local-variable 'git-show-unknown)
-  (run-hooks 'git-status-mode-hook)))
-
-(defun git-find-status-buffer (dir)
-  "Find the git status buffer handling a specified directory."
-  (let ((list (buffer-list))
-        (fulldir (expand-file-name dir))
-        found)
-    (while (and list (not found))
-      (let ((buffer (car list)))
-        (with-current-buffer buffer
-          (when (and list-buffers-directory
-                     (string-equal fulldir (expand-file-name list-buffers-directory))
-		     (eq major-mode 'git-status-mode))
-            (setq found buffer))))
-      (setq list (cdr list)))
-    found))
-
-(defun git-status (dir)
-  "Entry point into git-status mode."
-  (interactive "DSelect directory: ")
-  (setq dir (git-get-top-dir dir))
-  (if (file-exists-p (concat (file-name-as-directory dir) ".git"))
-      (let ((buffer (or (and git-reuse-status-buffer (git-find-status-buffer dir))
-                        (create-file-buffer (expand-file-name "*git-status*" dir)))))
-        (switch-to-buffer buffer)
-        (cd dir)
-        (git-status-mode)
-        (git-refresh-status)
-        (goto-char (point-min))
-        (add-hook 'after-save-hook 'git-update-saved-file))
-    (message "%s is not a git working tree." dir)))
-
-(defun git-update-saved-file ()
-  "Update the corresponding git-status buffer when a file is saved.
-Meant to be used in `after-save-hook'."
-  (let* ((file (expand-file-name buffer-file-name))
-         (dir (condition-case nil (git-get-top-dir (file-name-directory file)) (error nil)))
-         (buffer (and dir (git-find-status-buffer dir))))
-    (when buffer
-      (with-current-buffer buffer
-        (let ((filename (file-relative-name file dir)))
-          ; skip files located inside the .git directory
-          (unless (string-match "^\\.git/" filename)
-            (git-call-process nil "add" "--refresh" "--" filename)
-            (git-update-status-files (list filename))))))))
-
-(defun git-help ()
-  "Display help for Git mode."
-  (interactive)
-  (describe-function 'git-status-mode))
-
-(provide 'git)
-;;; git.el ends here
+(error "git.el no longer ships with git. It's recommended to
+replace its use with Magit, or simply delete references to git.el
+in your initialization file(s). See contrib/emacs/README in git's
+sources (https://github.com/git/git/blob/master/contrib/emacs/README)
+for suggested alternatives and for why this happened. Emacs's own
+VC mode and Magit are viable alternatives.")
diff --git a/contrib/fast-import/import-tars.perl b/contrib/fast-import/import-tars.perl
index d60b431..e800d9f 100755
--- a/contrib/fast-import/import-tars.perl
+++ b/contrib/fast-import/import-tars.perl
@@ -63,6 +63,8 @@
 	my $have_top_dir = 1;
 	my ($top_dir, %files);
 
+	my $next_path = '';
+
 	while (read(I, $_, 512) == 512) {
 		my ($name, $mode, $uid, $gid, $size, $mtime,
 			$chksum, $typeflag, $linkname, $magic,
@@ -70,6 +72,13 @@
 			$prefix) = unpack 'Z100 Z8 Z8 Z8 Z12 Z12
 			Z8 Z1 Z100 Z6
 			Z2 Z32 Z32 Z8 Z8 Z*', $_;
+
+		unless ($next_path eq '') {
+			# Recover name from previous extended header
+			$name = $next_path;
+			$next_path = '';
+		}
+
 		last unless length($name);
 		if ($name eq '././@LongLink') {
 			# GNU tar extension
@@ -90,13 +99,31 @@
 			Z8 Z1 Z100 Z6
 			Z2 Z32 Z32 Z8 Z8 Z*', $_;
 		}
-		next if $name =~ m{/\z};
 		$mode = oct $mode;
 		$size = oct $size;
 		$mtime = oct $mtime;
 		next if $typeflag == 5; # directory
 
-		if ($typeflag != 1) { # handle hard links later
+		if ($typeflag eq 'x') { # extended header
+			# If extended header, check for path
+			my $pax_header = '';
+			while ($size > 0 && read(I, $_, 512) == 512) {
+				$pax_header = $pax_header . substr($_, 0, $size);
+				$size -= 512;
+			}
+
+			my @lines = split /\n/, $pax_header;
+			foreach my $line (@lines) {
+				my ($len, $entry) = split / /, $line;
+				my ($key, $value) = split /=/, $entry;
+				if ($key eq 'path') {
+					$next_path = $value;
+				}
+			}
+			next;
+		} elsif ($name =~ m{/\z}) { # directory
+			next;
+		} elsif ($typeflag != 1) { # handle hard links later
 			print FI "blob\n", "mark :$next_mark\n";
 			if ($typeflag == 2) { # symbolic link
 				print FI "data ", length($linkname), "\n",
diff --git a/contrib/mw-to-git/Makefile b/contrib/mw-to-git/Makefile
index a4b6f7a..4e60351 100644
--- a/contrib/mw-to-git/Makefile
+++ b/contrib/mw-to-git/Makefile
@@ -21,8 +21,9 @@
 INSTALL = install
 
 SCRIPT_PERL_FULL=$(patsubst %,$(HERE)/%,$(SCRIPT_PERL))
-INSTLIBDIR=$(shell $(MAKE) -C $(GIT_ROOT_DIR)/perl \
-                -s --no-print-directory instlibdir)
+INSTLIBDIR=$(shell $(MAKE) -C $(GIT_ROOT_DIR)/ \
+                -s --no-print-directory prefix=$(prefix) \
+                perllibdir=$(perllibdir) perllibdir)
 DESTDIR_SQ = $(subst ','\'',$(DESTDIR))
 INSTLIBDIR_SQ = $(subst ','\'',$(INSTLIBDIR))
 
diff --git a/convert.c b/convert.c
index c480097..64d0d30 100644
--- a/convert.c
+++ b/convert.c
@@ -7,6 +7,7 @@
 #include "sigchain.h"
 #include "pkt-line.h"
 #include "sub-process.h"
+#include "utf8.h"
 
 /*
  * convert.c - convert a file when checking it out and checking it in.
@@ -265,6 +266,241 @@
 
 }
 
+static int validate_encoding(const char *path, const char *enc,
+		      const char *data, size_t len, int die_on_error)
+{
+	/* We only check for UTF here as UTF?? can be an alias for UTF-?? */
+	if (istarts_with(enc, "UTF")) {
+		/*
+		 * Check for detectable errors in UTF encodings
+		 */
+		if (has_prohibited_utf_bom(enc, data, len)) {
+			const char *error_msg = _(
+				"BOM is prohibited in '%s' if encoded as %s");
+			/*
+			 * This advice is shown for UTF-??BE and UTF-??LE encodings.
+			 * We cut off the last two characters of the encoding name
+			 * to generate the encoding name suitable for BOMs.
+			 */
+			const char *advise_msg = _(
+				"The file '%s' contains a byte order "
+				"mark (BOM). Please use UTF-%s as "
+				"working-tree-encoding.");
+			const char *stripped = NULL;
+			char *upper = xstrdup_toupper(enc);
+			upper[strlen(upper)-2] = '\0';
+			if (!skip_prefix(upper, "UTF-", &stripped))
+				skip_prefix(stripped, "UTF", &stripped);
+			advise(advise_msg, path, stripped);
+			free(upper);
+			if (die_on_error)
+				die(error_msg, path, enc);
+			else {
+				return error(error_msg, path, enc);
+			}
+
+		} else if (is_missing_required_utf_bom(enc, data, len)) {
+			const char *error_msg = _(
+				"BOM is required in '%s' if encoded as %s");
+			const char *advise_msg = _(
+				"The file '%s' is missing a byte order "
+				"mark (BOM). Please use UTF-%sBE or UTF-%sLE "
+				"(depending on the byte order) as "
+				"working-tree-encoding.");
+			const char *stripped = NULL;
+			char *upper = xstrdup_toupper(enc);
+			if (!skip_prefix(upper, "UTF-", &stripped))
+				skip_prefix(stripped, "UTF", &stripped);
+			advise(advise_msg, path, stripped, stripped);
+			free(upper);
+			if (die_on_error)
+				die(error_msg, path, enc);
+			else {
+				return error(error_msg, path, enc);
+			}
+		}
+
+	}
+	return 0;
+}
+
+static void trace_encoding(const char *context, const char *path,
+			   const char *encoding, const char *buf, size_t len)
+{
+	static struct trace_key coe = TRACE_KEY_INIT(WORKING_TREE_ENCODING);
+	struct strbuf trace = STRBUF_INIT;
+	int i;
+
+	strbuf_addf(&trace, "%s (%s, considered %s):\n", context, path, encoding);
+	for (i = 0; i < len && buf; ++i) {
+		strbuf_addf(
+			&trace,"| \e[2m%2i:\e[0m %2x \e[2m%c\e[0m%c",
+			i,
+			(unsigned char) buf[i],
+			(buf[i] > 32 && buf[i] < 127 ? buf[i] : ' '),
+			((i+1) % 8 && (i+1) < len ? ' ' : '\n')
+		);
+	}
+	strbuf_addchars(&trace, '\n', 1);
+
+	trace_strbuf(&coe, &trace);
+	strbuf_release(&trace);
+}
+
+static int check_roundtrip(const char *enc_name)
+{
+	/*
+	 * check_roundtrip_encoding contains a string of comma and/or
+	 * space separated encodings (eg. "UTF-16, ASCII, CP1125").
+	 * Search for the given encoding in that string.
+	 */
+	const char *found = strcasestr(check_roundtrip_encoding, enc_name);
+	const char *next;
+	int len;
+	if (!found)
+		return 0;
+	next = found + strlen(enc_name);
+	len = strlen(check_roundtrip_encoding);
+	return (found && (
+			/*
+			 * check that the found encoding is at the
+			 * beginning of check_roundtrip_encoding or
+			 * that it is prefixed with a space or comma
+			 */
+			found == check_roundtrip_encoding || (
+				(isspace(found[-1]) || found[-1] == ',')
+			)
+		) && (
+			/*
+			 * check that the found encoding is at the
+			 * end of check_roundtrip_encoding or
+			 * that it is suffixed with a space or comma
+			 */
+			next == check_roundtrip_encoding + len || (
+				next < check_roundtrip_encoding + len &&
+				(isspace(next[0]) || next[0] == ',')
+			)
+		));
+}
+
+static const char *default_encoding = "UTF-8";
+
+static int encode_to_git(const char *path, const char *src, size_t src_len,
+			 struct strbuf *buf, const char *enc, int conv_flags)
+{
+	char *dst;
+	int dst_len;
+	int die_on_error = conv_flags & CONV_WRITE_OBJECT;
+
+	/*
+	 * No encoding is specified or there is nothing to encode.
+	 * Tell the caller that the content was not modified.
+	 */
+	if (!enc || (src && !src_len))
+		return 0;
+
+	/*
+	 * Looks like we got called from "would_convert_to_git()".
+	 * This means Git wants to know if it would encode (= modify!)
+	 * the content. Let's answer with "yes", since an encoding was
+	 * specified.
+	 */
+	if (!buf && !src)
+		return 1;
+
+	if (validate_encoding(path, enc, src, src_len, die_on_error))
+		return 0;
+
+	trace_encoding("source", path, enc, src, src_len);
+	dst = reencode_string_len(src, src_len, default_encoding, enc,
+				  &dst_len);
+	if (!dst) {
+		/*
+		 * We could add the blob "as-is" to Git. However, on checkout
+		 * we would try to reencode to the original encoding. This
+		 * would fail and we would leave the user with a messed-up
+		 * working tree. Let's try to avoid this by screaming loud.
+		 */
+		const char* msg = _("failed to encode '%s' from %s to %s");
+		if (die_on_error)
+			die(msg, path, enc, default_encoding);
+		else {
+			error(msg, path, enc, default_encoding);
+			return 0;
+		}
+	}
+	trace_encoding("destination", path, default_encoding, dst, dst_len);
+
+	/*
+	 * UTF supports lossless conversion round tripping [1] and conversions
+	 * between UTF and other encodings are mostly round trip safe as
+	 * Unicode aims to be a superset of all other character encodings.
+	 * However, certain encodings (e.g. SHIFT-JIS) are known to have round
+	 * trip issues [2]. Check the round trip conversion for all encodings
+	 * listed in core.checkRoundtripEncoding.
+	 *
+	 * The round trip check is only performed if content is written to Git.
+	 * This ensures that no information is lost during conversion to/from
+	 * the internal UTF-8 representation.
+	 *
+	 * Please note, the code below is not tested because I was not able to
+	 * generate a faulty round trip without an iconv error. Iconv errors
+	 * are already caught above.
+	 *
+	 * [1] http://unicode.org/faq/utf_bom.html#gen2
+	 * [2] https://support.microsoft.com/en-us/help/170559/prb-conversion-problem-between-shift-jis-and-unicode
+	 */
+	if (die_on_error && check_roundtrip(enc)) {
+		char *re_src;
+		int re_src_len;
+
+		re_src = reencode_string_len(dst, dst_len,
+					     enc, default_encoding,
+					     &re_src_len);
+
+		trace_printf("Checking roundtrip encoding for %s...\n", enc);
+		trace_encoding("reencoded source", path, enc,
+			       re_src, re_src_len);
+
+		if (!re_src || src_len != re_src_len ||
+		    memcmp(src, re_src, src_len)) {
+			const char* msg = _("encoding '%s' from %s to %s and "
+					    "back is not the same");
+			die(msg, path, enc, default_encoding);
+		}
+
+		free(re_src);
+	}
+
+	strbuf_attach(buf, dst, dst_len, dst_len + 1);
+	return 1;
+}
+
+static int encode_to_worktree(const char *path, const char *src, size_t src_len,
+			      struct strbuf *buf, const char *enc)
+{
+	char *dst;
+	int dst_len;
+
+	/*
+	 * No encoding is specified or there is nothing to encode.
+	 * Tell the caller that the content was not modified.
+	 */
+	if (!enc || (src && !src_len))
+		return 0;
+
+	dst = reencode_string_len(src, src_len, enc, default_encoding,
+				  &dst_len);
+	if (!dst) {
+		error("failed to encode '%s' from %s to %s",
+			path, default_encoding, enc);
+		return 0;
+	}
+
+	strbuf_attach(buf, dst, dst_len, dst_len + 1);
+	return 1;
+}
+
 static int crlf_to_git(const struct index_state *istate,
 		       const char *path, const char *src, size_t len,
 		       struct strbuf *buf,
@@ -978,6 +1214,24 @@
 	return 1;
 }
 
+static const char *git_path_check_encoding(struct attr_check_item *check)
+{
+	const char *value = check->value;
+
+	if (ATTR_UNSET(value) || !strlen(value))
+		return NULL;
+
+	if (ATTR_TRUE(value) || ATTR_FALSE(value)) {
+		die(_("true/false are no valid working-tree-encodings"));
+	}
+
+	/* Don't encode to the default encoding */
+	if (same_encoding(value, default_encoding))
+		return NULL;
+
+	return value;
+}
+
 static enum crlf_action git_path_check_crlf(struct attr_check_item *check)
 {
 	const char *value = check->value;
@@ -1033,6 +1287,7 @@
 	enum crlf_action attr_action; /* What attr says */
 	enum crlf_action crlf_action; /* When no attr is set, use core.autocrlf */
 	int ident;
+	const char *working_tree_encoding; /* Supported encoding or default encoding if NULL */
 };
 
 static void convert_attrs(struct conv_attrs *ca, const char *path)
@@ -1041,7 +1296,8 @@
 
 	if (!check) {
 		check = attr_check_initl("crlf", "ident", "filter",
-					 "eol", "text", NULL);
+					 "eol", "text", "working-tree-encoding",
+					 NULL);
 		user_convert_tail = &user_convert;
 		git_config(read_convert_config, NULL);
 	}
@@ -1064,6 +1320,7 @@
 			else if (eol_attr == EOL_CRLF)
 				ca->crlf_action = CRLF_TEXT_CRLF;
 		}
+		ca->working_tree_encoding = git_path_check_encoding(ccheck + 5);
 	} else {
 		ca->drv = NULL;
 		ca->crlf_action = CRLF_UNDEFINED;
@@ -1144,6 +1401,13 @@
 		src = dst->buf;
 		len = dst->len;
 	}
+
+	ret |= encode_to_git(path, src, len, dst, ca.working_tree_encoding, conv_flags);
+	if (ret && dst) {
+		src = dst->buf;
+		len = dst->len;
+	}
+
 	if (!(conv_flags & CONV_EOL_KEEP_CRLF)) {
 		ret |= crlf_to_git(istate, path, src, len, dst, ca.crlf_action, conv_flags);
 		if (ret && dst) {
@@ -1167,6 +1431,7 @@
 	if (!apply_filter(path, NULL, 0, fd, dst, ca.drv, CAP_CLEAN, NULL))
 		die("%s: clean filter '%s' failed", path, ca.drv->name);
 
+	encode_to_git(path, dst->buf, dst->len, dst, ca.working_tree_encoding, conv_flags);
 	crlf_to_git(istate, path, dst->buf, dst->len, dst, ca.crlf_action, conv_flags);
 	ident_to_git(path, dst->buf, dst->len, dst, ca.ident);
 }
@@ -1198,6 +1463,12 @@
 		}
 	}
 
+	ret |= encode_to_worktree(path, src, len, dst, ca.working_tree_encoding);
+	if (ret) {
+		src = dst->buf;
+		len = dst->len;
+	}
+
 	ret_filter = apply_filter(
 		path, src, len, -1, dst, ca.drv, CAP_SMUDGE, dco);
 	if (!ret_filter && ca.drv && ca.drv->required)
@@ -1664,6 +1935,9 @@
 	if (ca.drv && (ca.drv->process || ca.drv->smudge || ca.drv->clean))
 		return NULL;
 
+	if (ca.working_tree_encoding)
+		return NULL;
+
 	if (ca.crlf_action == CRLF_AUTO || ca.crlf_action == CRLF_AUTO_CRLF)
 		return NULL;
 
diff --git a/convert.h b/convert.h
index 2e9b4f4..01385d9 100644
--- a/convert.h
+++ b/convert.h
@@ -12,6 +12,7 @@
 #define CONV_EOL_RNDTRP_WARN  (1<<1) /* Warn if CRLF to LF to CRLF is different */
 #define CONV_EOL_RENORMALIZE  (1<<2) /* Convert CRLF to LF */
 #define CONV_EOL_KEEP_CRLF    (1<<3) /* Keep CRLF line endings as is */
+#define CONV_WRITE_OBJECT     (1<<4) /* Content is written to the index */
 
 extern int global_conv_flags_eol;
 
@@ -55,6 +56,7 @@
 };
 
 extern enum eol core_eol;
+extern char *check_roundtrip_encoding;
 extern const char *get_cached_convert_stats_ascii(const struct index_state *istate,
 						  const char *path);
 extern const char *get_wt_convert_stats_ascii(const char *path);
diff --git a/csum-file.c b/csum-file.c
index 5eda7fb..53ce37f 100644
--- a/csum-file.c
+++ b/csum-file.c
@@ -53,7 +53,7 @@
 	}
 }
 
-int hashclose(struct hashfile *f, unsigned char *result, unsigned int flags)
+int finalize_hashfile(struct hashfile *f, unsigned char *result, unsigned int flags)
 {
 	int fd;
 
@@ -61,11 +61,11 @@
 	the_hash_algo->final_fn(f->buffer, &f->ctx);
 	if (result)
 		hashcpy(result, f->buffer);
-	if (flags & (CSUM_CLOSE | CSUM_FSYNC)) {
-		/* write checksum and close fd */
+	if (flags & CSUM_HASH_IN_STREAM)
 		flush(f, f->buffer, the_hash_algo->rawsz);
-		if (flags & CSUM_FSYNC)
-			fsync_or_die(f->fd, f->name);
+	if (flags & CSUM_FSYNC)
+		fsync_or_die(f->fd, f->name);
+	if (flags & CSUM_CLOSE) {
 		if (close(f->fd))
 			die_errno("%s: sha1 file error on close", f->name);
 		fd = 0;
diff --git a/csum-file.h b/csum-file.h
index 992e5c0..c5a2e33 100644
--- a/csum-file.h
+++ b/csum-file.h
@@ -26,14 +26,15 @@
 extern void hashfile_checkpoint(struct hashfile *, struct hashfile_checkpoint *);
 extern int hashfile_truncate(struct hashfile *, struct hashfile_checkpoint *);
 
-/* hashclose flags */
-#define CSUM_CLOSE	1
-#define CSUM_FSYNC	2
+/* finalize_hashfile flags */
+#define CSUM_CLOSE		1
+#define CSUM_FSYNC		2
+#define CSUM_HASH_IN_STREAM	4
 
 extern struct hashfile *hashfd(int fd, const char *name);
 extern struct hashfile *hashfd_check(const char *name);
 extern struct hashfile *hashfd_throughput(int fd, const char *name, struct progress *tp);
-extern int hashclose(struct hashfile *, unsigned char *, unsigned int);
+extern int finalize_hashfile(struct hashfile *, unsigned char *, unsigned int);
 extern void hashwrite(struct hashfile *, const void *, unsigned int);
 extern void hashflush(struct hashfile *f);
 extern void crc32_begin(struct hashfile *);
diff --git a/date.c b/date.c
index c3e673f..49f943e 100644
--- a/date.c
+++ b/date.c
@@ -185,7 +185,7 @@
 {
 	static struct date_mode mode;
 	if (type == DATE_STRFTIME)
-		die("BUG: cannot create anonymous strftime date_mode struct");
+		BUG("cannot create anonymous strftime date_mode struct");
 	mode.type = type;
 	mode.local = 0;
 	return &mode;
diff --git a/detect-compiler b/detect-compiler
new file mode 100755
index 0000000..70b7544
--- /dev/null
+++ b/detect-compiler
@@ -0,0 +1,53 @@
+#!/bin/sh
+#
+# Probe the compiler for vintage, version, etc. This is used for setting
+# optional make knobs under the DEVELOPER knob.
+
+CC="$*"
+
+# we get something like (this is at least true for gcc and clang)
+#
+# FreeBSD clang version 3.4.1 (tags/RELEASE...)
+get_version_line() {
+	$CC -v 2>&1 | grep ' version '
+}
+
+get_family() {
+	get_version_line | sed 's/^\(.*\) version [0-9][^ ]* .*/\1/'
+}
+
+get_version() {
+	get_version_line | sed 's/^.* version \([0-9][^ ]*\) .*/\1/'
+}
+
+print_flags() {
+	family=$1
+	version=$(get_version | cut -f 1 -d .)
+
+	# Print a feature flag not only for the current version, but also
+	# for any prior versions we encompass. This avoids needing to do
+	# numeric comparisons in make, which are awkward.
+	while test "$version" -gt 0
+	do
+		echo $family$version
+		version=$((version - 1))
+	done
+}
+
+case "$(get_family)" in
+gcc)
+	print_flags gcc
+	;;
+clang)
+	print_flags clang
+	;;
+"FreeBSD clang")
+	print_flags clang
+	;;
+"Apple LLVM")
+	print_flags clang
+	;;
+*)
+	: unknown compiler family
+	;;
+esac
diff --git a/diff.c b/diff.c
index 1289df4..136d44b 100644
--- a/diff.c
+++ b/diff.c
@@ -177,7 +177,7 @@
 	return 0;
 }
 
-static int git_config_rename(const char *var, const char *value)
+int git_config_rename(const char *var, const char *value)
 {
 	if (!value)
 		return DIFF_DETECT_RENAME;
@@ -1184,7 +1184,7 @@
 		fputs(o->stat_sep, o->file);
 		break;
 	default:
-		die("BUG: unknown diff symbol");
+		BUG("unknown diff symbol");
 	}
 	strbuf_release(&sb);
 }
@@ -1343,7 +1343,7 @@
 	for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 		if (!diff_temp[i].name)
 			return diff_temp + i;
-	die("BUG: diff is failing to clean up its tempfiles");
+	BUG("diff is failing to clean up its tempfiles");
 }
 
 static void remove_tempfile(void)
@@ -3472,7 +3472,7 @@
 	 * objects however would tend to be slower as they need
 	 * to be individually opened and inflated.
 	 */
-	if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
+	if (!FAST_WORKING_DIRECTORY && !want_file && has_object_pack(oid))
 		return 0;
 
 	/*
@@ -3638,7 +3638,8 @@
 	else {
 		enum object_type type;
 		if (size_only || (flags & CHECK_BINARY)) {
-			type = oid_object_info(&s->oid, &s->size);
+			type = oid_object_info(the_repository, &s->oid,
+					       &s->size);
 			if (type < 0)
 				die("unable to read %s",
 				    oid_to_hex(&s->oid));
@@ -3840,7 +3841,7 @@
 		if (abbrev < 0)
 			abbrev = FALLBACK_DEFAULT_ABBREV;
 		if (abbrev > GIT_SHA1_HEXSZ)
-			die("BUG: oid abbreviation out of range: %d", abbrev);
+			BUG("oid abbreviation out of range: %d", abbrev);
 		if (abbrev)
 			hex[abbrev] = '\0';
 		return hex;
@@ -3897,13 +3898,14 @@
 		*must_show_header = 0;
 	}
 	if (one && two && oidcmp(&one->oid, &two->oid)) {
-		int abbrev = o->flags.full_index ? 40 : DEFAULT_ABBREV;
+		const unsigned hexsz = the_hash_algo->hexsz;
+		int abbrev = o->flags.full_index ? hexsz : DEFAULT_ABBREV;
 
 		if (o->flags.binary) {
 			mmfile_t mf;
 			if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
 			    (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
-				abbrev = 40;
+				abbrev = hexsz;
 		}
 		strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
 			    diff_abbrev_oid(&one->oid, abbrev),
@@ -4138,6 +4140,11 @@
 			      DIFF_FORMAT_NAME_STATUS |
 			      DIFF_FORMAT_CHECKDIFF |
 			      DIFF_FORMAT_NO_OUTPUT;
+	/*
+	 * This must be signed because we're comparing against a potentially
+	 * negative value.
+	 */
+	const int hexsz = the_hash_algo->hexsz;
 
 	if (options->set_default)
 		options->set_default(options);
@@ -4218,8 +4225,8 @@
 			 */
 			read_cache();
 	}
-	if (40 < options->abbrev)
-		options->abbrev = 40; /* full */
+	if (hexsz < options->abbrev)
+		options->abbrev = hexsz; /* full */
 
 	/*
 	 * It does not make sense to show the first hit we happened
@@ -4334,7 +4341,7 @@
 	int argcount = 1;
 
 	if (!skip_prefix(arg, "--stat", &arg))
-		die("BUG: stat option does not begin with --stat: %s", arg);
+		BUG("stat option does not begin with --stat: %s", arg);
 	end = (char *)arg;
 
 	switch (*arg) {
@@ -4797,8 +4804,8 @@
 		options->abbrev = strtoul(arg, NULL, 10);
 		if (options->abbrev < MINIMUM_ABBREV)
 			options->abbrev = MINIMUM_ABBREV;
-		else if (40 < options->abbrev)
-			options->abbrev = 40;
+		else if (the_hash_algo->hexsz < options->abbrev)
+			options->abbrev = the_hash_algo->hexsz;
 	}
 	else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
 		options->a_prefix = optarg;
@@ -5519,7 +5526,7 @@
 	struct diff_queue_struct *q = &diff_queued_diff;
 
 	if (WSEH_NEW & WS_RULE_MASK)
-		die("BUG: WS rules bit mask overlaps with diff symbol flags");
+		BUG("WS rules bit mask overlaps with diff symbol flags");
 
 	if (o->color_moved)
 		o->emitted_symbols = &esm;
@@ -6053,7 +6060,7 @@
 	}
 
 	if (!driver->textconv)
-		die("BUG: fill_textconv called with non-textconv driver");
+		BUG("fill_textconv called with non-textconv driver");
 
 	if (driver->textconv_cache && df->oid_valid) {
 		*outbuf = notes_cache_get(driver->textconv_cache,
diff --git a/diff.h b/diff.h
index d29560f..dedac47 100644
--- a/diff.h
+++ b/diff.h
@@ -324,6 +324,7 @@
 extern void diff_setup(struct diff_options *);
 extern int diff_opt_parse(struct diff_options *, const char **, int, const char *);
 extern void diff_setup_done(struct diff_options *);
+extern int git_config_rename(const char *var, const char *value);
 
 #define DIFF_DETECT_RENAME	1
 #define DIFF_DETECT_COPY	2
diff --git a/diffcore-pickaxe.c b/diffcore-pickaxe.c
index 239ce51..800a899 100644
--- a/diffcore-pickaxe.c
+++ b/diffcore-pickaxe.c
@@ -215,7 +215,6 @@
 		/* The POSIX.2 people are surely sick */
 		char errbuf[1024];
 		regerror(err, regex, errbuf, 1024);
-		regfree(regex);
 		die("invalid regex: %s", errbuf);
 	}
 }
diff --git a/dir-iterator.c b/dir-iterator.c
index 34182a9..f2dcd82 100644
--- a/dir-iterator.c
+++ b/dir-iterator.c
@@ -188,7 +188,7 @@
 	struct dir_iterator *dir_iterator = &iter->base;
 
 	if (!path || !*path)
-		die("BUG: empty path passed to dir_iterator_begin()");
+		BUG("empty path passed to dir_iterator_begin()");
 
 	strbuf_init(&iter->base.path, PATH_MAX);
 	strbuf_addstr(&iter->base.path, path);
diff --git a/dir.c b/dir.c
index 63a917b..ccf8b49 100644
--- a/dir.c
+++ b/dir.c
@@ -19,6 +19,7 @@
 #include "varint.h"
 #include "ewah/ewok.h"
 #include "fsmonitor.h"
+#include "submodule-config.h"
 
 /*
  * Tells read_directory_recursive how a file or directory should be treated.
@@ -828,7 +829,7 @@
 		if (size == 0) {
 			if (oid_stat) {
 				fill_stat_data(&oid_stat->stat, &st);
-				oidcpy(&oid_stat->oid, &empty_blob_oid);
+				oidcpy(&oid_stat->oid, the_hash_algo->empty_blob);
 				oid_stat->valid = 1;
 			}
 			close(fd);
@@ -1240,11 +1241,11 @@
 		    (!untracked || !untracked->valid ||
 		     /*
 		      * .. and .gitignore does not exist before
-		      * (i.e. null exclude_sha1). Then we can skip
+		      * (i.e. null exclude_oid). Then we can skip
 		      * loading .gitignore, which would result in
 		      * ENOENT anyway.
 		      */
-		     !is_null_sha1(untracked->exclude_sha1))) {
+		     !is_null_oid(&untracked->exclude_oid))) {
 			/*
 			 * dir->basebuf gets reused by the traversal, but we
 			 * need fname to remain unchanged to ensure the src
@@ -1275,9 +1276,9 @@
 		 * order, though, if you do that.
 		 */
 		if (untracked &&
-		    hashcmp(oid_stat.oid.hash, untracked->exclude_sha1)) {
+		    oidcmp(&oid_stat.oid, &untracked->exclude_oid)) {
 			invalidate_gitignore(dir->untracked, untracked);
-			hashcpy(untracked->exclude_sha1, oid_stat.oid.hash);
+			oidcpy(&untracked->exclude_oid, &oid_stat.oid);
 		}
 		dir->exclude_stack = stk;
 		current = stk->baselen;
@@ -2622,9 +2623,10 @@
 		stat_data_to_disk(&stat_data, &untracked->stat_data);
 		strbuf_add(&wd->sb_stat, &stat_data, sizeof(stat_data));
 	}
-	if (!is_null_sha1(untracked->exclude_sha1)) {
+	if (!is_null_oid(&untracked->exclude_oid)) {
 		ewah_set(wd->sha1_valid, i);
-		strbuf_add(&wd->sb_sha1, untracked->exclude_sha1, 20);
+		strbuf_add(&wd->sb_sha1, untracked->exclude_oid.hash,
+			   the_hash_algo->rawsz);
 	}
 
 	intlen = encode_varint(untracked->untracked_nr, intbuf);
@@ -2825,16 +2827,16 @@
 	ud->valid = 1;
 }
 
-static void read_sha1(size_t pos, void *cb)
+static void read_oid(size_t pos, void *cb)
 {
 	struct read_data *rd = cb;
 	struct untracked_cache_dir *ud = rd->ucd[pos];
-	if (rd->data + 20 > rd->end) {
+	if (rd->data + the_hash_algo->rawsz > rd->end) {
 		rd->data = rd->end + 1;
 		return;
 	}
-	hashcpy(ud->exclude_sha1, rd->data);
-	rd->data += 20;
+	hashcpy(ud->exclude_oid.hash, rd->data);
+	rd->data += the_hash_algo->rawsz;
 }
 
 static void load_oid_stat(struct oid_stat *oid_stat, const unsigned char *data,
@@ -2917,7 +2919,7 @@
 	ewah_each_bit(rd.check_only, set_check_only, &rd);
 	rd.data = next + len;
 	ewah_each_bit(rd.valid, read_stat, &rd);
-	ewah_each_bit(rd.sha1_valid, read_sha1, &rd);
+	ewah_each_bit(rd.sha1_valid, read_oid, &rd);
 	next = rd.data;
 
 done:
@@ -2992,7 +2994,7 @@
 {
 	if (!istate->untracked || !istate->untracked->root)
 		return;
-	if (!safe_path && !verify_path(path))
+	if (!safe_path && !verify_path(path, 0))
 		return;
 	invalidate_one_component(istate->untracked, istate->untracked->root,
 				 path, strlen(path));
@@ -3010,8 +3012,57 @@
 	untracked_cache_invalidate_path(istate, path, 1);
 }
 
-/* Update gitfile and core.worktree setting to connect work tree and git dir */
-void connect_work_tree_and_git_dir(const char *work_tree_, const char *git_dir_)
+static void connect_wt_gitdir_in_nested(const char *sub_worktree,
+					const char *sub_gitdir)
+{
+	int i;
+	struct repository subrepo;
+	struct strbuf sub_wt = STRBUF_INIT;
+	struct strbuf sub_gd = STRBUF_INIT;
+
+	const struct submodule *sub;
+
+	/* If the submodule has no working tree, we can ignore it. */
+	if (repo_init(&subrepo, sub_gitdir, sub_worktree))
+		return;
+
+	if (repo_read_index(&subrepo) < 0)
+		die("index file corrupt in repo %s", subrepo.gitdir);
+
+	for (i = 0; i < subrepo.index->cache_nr; i++) {
+		const struct cache_entry *ce = subrepo.index->cache[i];
+
+		if (!S_ISGITLINK(ce->ce_mode))
+			continue;
+
+		while (i + 1 < subrepo.index->cache_nr &&
+		       !strcmp(ce->name, subrepo.index->cache[i + 1]->name))
+			/*
+			 * Skip entries with the same name in different stages
+			 * to make sure an entry is returned only once.
+			 */
+			i++;
+
+		sub = submodule_from_path(&subrepo, &null_oid, ce->name);
+		if (!sub || !is_submodule_active(&subrepo, ce->name))
+			/* .gitmodules broken or inactive sub */
+			continue;
+
+		strbuf_reset(&sub_wt);
+		strbuf_reset(&sub_gd);
+		strbuf_addf(&sub_wt, "%s/%s", sub_worktree, sub->path);
+		strbuf_addf(&sub_gd, "%s/modules/%s", sub_gitdir, sub->name);
+
+		connect_work_tree_and_git_dir(sub_wt.buf, sub_gd.buf, 1);
+	}
+	strbuf_release(&sub_wt);
+	strbuf_release(&sub_gd);
+	repo_clear(&subrepo);
+}
+
+void connect_work_tree_and_git_dir(const char *work_tree_,
+				   const char *git_dir_,
+				   int recurse_into_nested)
 {
 	struct strbuf gitfile_sb = STRBUF_INIT;
 	struct strbuf cfg_sb = STRBUF_INIT;
@@ -3041,6 +3092,10 @@
 	strbuf_release(&gitfile_sb);
 	strbuf_release(&cfg_sb);
 	strbuf_release(&rel_path);
+
+	if (recurse_into_nested)
+		connect_wt_gitdir_in_nested(work_tree, git_dir);
+
 	free(work_tree);
 	free(git_dir);
 }
@@ -3054,5 +3109,5 @@
 		die_errno(_("could not migrate git directory from '%s' to '%s'"),
 			old_git_dir, new_git_dir);
 
-	connect_work_tree_and_git_dir(path, new_git_dir);
+	connect_work_tree_and_git_dir(path, new_git_dir, 0);
 }
diff --git a/dir.h b/dir.h
index b0758b8..f5fdedb 100644
--- a/dir.h
+++ b/dir.h
@@ -3,6 +3,7 @@
 
 /* See Documentation/technical/api-directory-listing.txt */
 
+#include "cache.h"
 #include "strbuf.h"
 
 struct dir_entry {
@@ -118,8 +119,8 @@
 	/* all data except 'dirs' in this struct are good */
 	unsigned int valid : 1;
 	unsigned int recurse : 1;
-	/* null SHA-1 means this directory does not have .gitignore */
-	unsigned char exclude_sha1[20];
+	/* null object ID means this directory does not have .gitignore */
+	struct object_id exclude_oid;
 	char name[FLEX_ARRAY];
 };
 
@@ -359,7 +360,17 @@
 void write_untracked_extension(struct strbuf *out, struct untracked_cache *untracked);
 void add_untracked_cache(struct index_state *istate);
 void remove_untracked_cache(struct index_state *istate);
-extern void connect_work_tree_and_git_dir(const char *work_tree, const char *git_dir);
+
+/*
+ * Connect a worktree to a git directory by creating (or overwriting) a
+ * '.git' file containing the location of the git directory. In the git
+ * directory set the core.worktree setting to indicate where the worktree is.
+ * When `recurse_into_nested` is set, recurse into any nested submodules,
+ * connecting them as well.
+ */
+extern void connect_work_tree_and_git_dir(const char *work_tree,
+					  const char *git_dir,
+					  int recurse_into_nested);
 extern void relocate_gitdir(const char *path,
 			    const char *old_git_dir,
 			    const char *new_git_dir);
diff --git a/environment.c b/environment.c
index fd970b8..2a6de23 100644
--- a/environment.c
+++ b/environment.c
@@ -51,10 +51,11 @@
 const char *askpass_program;
 const char *excludes_file;
 enum auto_crlf auto_crlf = AUTO_CRLF_FALSE;
-int check_replace_refs = 1;
+int check_replace_refs = 1; /* NEEDSWORK: rename to read_replace_refs */
 char *git_replace_ref_base;
 enum eol core_eol = EOL_UNSET;
 int global_conv_flags_eol = CONV_EOL_RNDTRP_WARN;
+char *check_roundtrip_encoding = "SHIFT-JIS";
 unsigned whitespace_rule_cfg = WS_DEFAULT_RULE;
 enum branch_track git_branch_track = BRANCH_TRACK_REMOTE;
 enum rebase_setup_type autorebase = AUTOREBASE_NEVER;
@@ -65,6 +66,7 @@
 enum object_creation_mode object_creation_mode = OBJECT_CREATION_MODE;
 char *notes_ref_name;
 int grafts_replace_parents = 1;
+int core_commit_graph;
 int core_apply_sparse_checkout;
 int merge_log_config = -1;
 int precomposed_unicode = -1; /* see probe_utf8_pathname_composition() */
diff --git a/exec-cmd.c b/exec-cmd.c
index 8a82617..02d31ee 100644
--- a/exec-cmd.c
+++ b/exec-cmd.c
@@ -2,25 +2,53 @@
 #include "exec-cmd.h"
 #include "quote.h"
 #include "argv-array.h"
-#define MAX_ARGS	32
 
-static const char *argv_exec_path;
+#if defined(RUNTIME_PREFIX)
+
+#if defined(HAVE_NS_GET_EXECUTABLE_PATH)
+#include <mach-o/dyld.h>
+#endif
+
+#if defined(HAVE_BSD_KERN_PROC_SYSCTL)
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#endif
+
+#endif /* RUNTIME_PREFIX */
+
+#define MAX_ARGS 32
+
+static const char *system_prefix(void);
 
 #ifdef RUNTIME_PREFIX
-static const char *argv0_path;
+
+/**
+ * When using a runtime prefix, Git dynamically resolves paths relative to its
+ * executable.
+ *
+ * The method for determining the path of the executable is highly
+ * platform-specific.
+ */
+
+/**
+ * Path to the current Git executable. Resolved on startup by
+ * 'git_resolve_executable_dir'.
+ */
+static const char *executable_dirname;
 
 static const char *system_prefix(void)
 {
 	static const char *prefix;
 
-	assert(argv0_path);
-	assert(is_absolute_path(argv0_path));
+	assert(executable_dirname);
+	assert(is_absolute_path(executable_dirname));
 
 	if (!prefix &&
-	    !(prefix = strip_path_suffix(argv0_path, GIT_EXEC_PATH)) &&
-	    !(prefix = strip_path_suffix(argv0_path, BINDIR)) &&
-	    !(prefix = strip_path_suffix(argv0_path, "git"))) {
-		prefix = PREFIX;
+	    !(prefix = strip_path_suffix(executable_dirname, GIT_EXEC_PATH)) &&
+	    !(prefix = strip_path_suffix(executable_dirname, BINDIR)) &&
+	    !(prefix = strip_path_suffix(executable_dirname, "git"))) {
+		prefix = FALLBACK_RUNTIME_PREFIX;
 		trace_printf("RUNTIME_PREFIX requested, "
 				"but prefix computation failed.  "
 				"Using static fallback '%s'.\n", prefix);
@@ -28,27 +56,201 @@
 	return prefix;
 }
 
-void git_extract_argv0_path(const char *argv0)
+/*
+ * Resolves the executable path from argv[0], only if it is absolute.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path_from_argv0(struct strbuf *buf, const char *argv0)
 {
 	const char *slash;
 
 	if (!argv0 || !*argv0)
-		return;
+		return -1;
 
 	slash = find_last_dir_sep(argv0);
+	if (slash) {
+		trace_printf("trace: resolved executable path from argv0: %s\n",
+			     argv0);
+		strbuf_add_absolute_path(buf, argv0);
+		return 0;
+	}
+	return -1;
+}
 
+#ifdef PROCFS_EXECUTABLE_PATH
+/*
+ * Resolves the executable path by examining a procfs symlink.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path_procfs(struct strbuf *buf)
+{
+	if (strbuf_realpath(buf, PROCFS_EXECUTABLE_PATH, 0)) {
+		trace_printf(
+			"trace: resolved executable path from procfs: %s\n",
+			buf->buf);
+		return 0;
+	}
+	return -1;
+}
+#endif /* PROCFS_EXECUTABLE_PATH */
+
+#ifdef HAVE_BSD_KERN_PROC_SYSCTL
+/*
+ * Resolves the executable path using KERN_PROC_PATHNAME BSD sysctl.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path_bsd_sysctl(struct strbuf *buf)
+{
+	int mib[4];
+	char path[MAXPATHLEN];
+	size_t cb = sizeof(path);
+
+	mib[0] = CTL_KERN;
+	mib[1] = KERN_PROC;
+	mib[2] = KERN_PROC_PATHNAME;
+	mib[3] = -1;
+	if (!sysctl(mib, 4, path, &cb, NULL, 0)) {
+		trace_printf(
+			"trace: resolved executable path from sysctl: %s\n",
+			path);
+		strbuf_addstr(buf, path);
+		return 0;
+	}
+	return -1;
+}
+#endif /* HAVE_BSD_KERN_PROC_SYSCTL */
+
+#ifdef HAVE_NS_GET_EXECUTABLE_PATH
+/*
+ * Resolves the executable path by querying Darwin application stack.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path_darwin(struct strbuf *buf)
+{
+	char path[PATH_MAX];
+	uint32_t size = sizeof(path);
+	if (!_NSGetExecutablePath(path, &size)) {
+		trace_printf(
+			"trace: resolved executable path from Darwin stack: %s\n",
+			path);
+		strbuf_addstr(buf, path);
+		return 0;
+	}
+	return -1;
+}
+#endif /* HAVE_NS_GET_EXECUTABLE_PATH */
+
+#ifdef HAVE_WPGMPTR
+/*
+ * Resolves the executable path by using the global variable _wpgmptr.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path_wpgmptr(struct strbuf *buf)
+{
+	int len = wcslen(_wpgmptr) * 3 + 1;
+	strbuf_grow(buf, len);
+	len = xwcstoutf(buf->buf, _wpgmptr, len);
+	if (len < 0)
+		return -1;
+	buf->len += len;
+	return 0;
+}
+#endif /* HAVE_WPGMPTR */
+
+/*
+ * Resolves the absolute path of the current executable.
+ *
+ * Returns 0 on success, -1 on failure.
+ */
+static int git_get_exec_path(struct strbuf *buf, const char *argv0)
+{
+	/*
+	 * Identifying the executable path is operating system specific.
+	 * Selectively employ all available methods in order of preference,
+	 * preferring highly-available authoritative methods over
+	 * selectively-available or non-authoritative methods.
+	 *
+	 * All cases fall back on resolving against argv[0] if there isn't a
+	 * better functional method. However, note that argv[0] can be
+	 * used-supplied on many operating systems, and is not authoritative
+	 * in those cases.
+	 *
+	 * Each of these functions returns 0 on success, so evaluation will stop
+	 * after the first successful method.
+	 */
+	if (
+#ifdef HAVE_BSD_KERN_PROC_SYSCTL
+		git_get_exec_path_bsd_sysctl(buf) &&
+#endif /* HAVE_BSD_KERN_PROC_SYSCTL */
+
+#ifdef HAVE_NS_GET_EXECUTABLE_PATH
+		git_get_exec_path_darwin(buf) &&
+#endif /* HAVE_NS_GET_EXECUTABLE_PATH */
+
+#ifdef PROCFS_EXECUTABLE_PATH
+		git_get_exec_path_procfs(buf) &&
+#endif /* PROCFS_EXECUTABLE_PATH */
+
+#ifdef HAVE_WPGMPTR
+		git_get_exec_path_wpgmptr(buf) &&
+#endif /* HAVE_WPGMPTR */
+
+		git_get_exec_path_from_argv0(buf, argv0)) {
+		return -1;
+	}
+
+	if (strbuf_normalize_path(buf)) {
+		trace_printf("trace: could not normalize path: %s\n", buf->buf);
+		return -1;
+	}
+
+	return 0;
+}
+
+void git_resolve_executable_dir(const char *argv0)
+{
+	struct strbuf buf = STRBUF_INIT;
+	char *resolved;
+	const char *slash;
+
+	if (git_get_exec_path(&buf, argv0)) {
+		trace_printf(
+			"trace: could not determine executable path from: %s\n",
+			argv0);
+		strbuf_release(&buf);
+		return;
+	}
+
+	resolved = strbuf_detach(&buf, NULL);
+	slash = find_last_dir_sep(resolved);
 	if (slash)
-		argv0_path = xstrndup(argv0, slash - argv0);
+		resolved[slash - resolved] = '\0';
+
+	executable_dirname = resolved;
+	trace_printf("trace: resolved executable dir: %s\n",
+		     executable_dirname);
 }
 
 #else
 
+/*
+ * When not using a runtime prefix, Git uses a hard-coded path.
+ */
 static const char *system_prefix(void)
 {
-	return PREFIX;
+	return FALLBACK_RUNTIME_PREFIX;
 }
 
-void git_extract_argv0_path(const char *argv0)
+/*
+ * This is called during initialization, but No work needs to be done here when
+ * runtime prefix is not being used.
+ */
+void git_resolve_executable_dir(const char *argv0)
 {
 }
 
@@ -65,32 +267,28 @@
 	return strbuf_detach(&d, NULL);
 }
 
-void git_set_argv_exec_path(const char *exec_path)
+static const char *exec_path_value;
+
+void git_set_exec_path(const char *exec_path)
 {
-	argv_exec_path = exec_path;
+	exec_path_value = exec_path;
 	/*
 	 * Propagate this setting to external programs.
 	 */
 	setenv(EXEC_PATH_ENVIRONMENT, exec_path, 1);
 }
 
-
-/* Returns the highest-priority, location to look for git programs. */
+/* Returns the highest-priority location to look for git programs. */
 const char *git_exec_path(void)
 {
-	static char *cached_exec_path;
-
-	if (argv_exec_path)
-		return argv_exec_path;
-
-	if (!cached_exec_path) {
+	if (!exec_path_value) {
 		const char *env = getenv(EXEC_PATH_ENVIRONMENT);
 		if (env && *env)
-			cached_exec_path = xstrdup(env);
+			exec_path_value = xstrdup(env);
 		else
-			cached_exec_path = system_path(GIT_EXEC_PATH);
+			exec_path_value = system_path(GIT_EXEC_PATH);
 	}
-	return cached_exec_path;
+	return exec_path_value;
 }
 
 static void add_path(struct strbuf *out, const char *path)
@@ -103,10 +301,12 @@
 
 void setup_path(void)
 {
+	const char *exec_path = git_exec_path();
 	const char *old_path = getenv("PATH");
 	struct strbuf new_path = STRBUF_INIT;
 
-	add_path(&new_path, git_exec_path());
+	git_set_exec_path(exec_path);
+	add_path(&new_path, exec_path);
 
 	if (old_path)
 		strbuf_addstr(&new_path, old_path);
@@ -125,7 +325,8 @@
 	return out->argv;
 }
 
-int execv_git_cmd(const char **argv) {
+int execv_git_cmd(const char **argv)
+{
 	struct argv_array nargv = ARGV_ARRAY_INIT;
 
 	prepare_git_cmd(&nargv, argv);
@@ -140,8 +341,7 @@
 	return -1;
 }
 
-
-int execl_git_cmd(const char *cmd,...)
+int execl_git_cmd(const char *cmd, ...)
 {
 	int argc;
 	const char *argv[MAX_ARGS + 1];
diff --git a/exec-cmd.h b/exec-cmd.h
index ff0b480..2522453 100644
--- a/exec-cmd.h
+++ b/exec-cmd.h
@@ -3,8 +3,8 @@
 
 struct argv_array;
 
-extern void git_set_argv_exec_path(const char *exec_path);
-extern void git_extract_argv0_path(const char *path);
+extern void git_set_exec_path(const char *exec_path);
+extern void git_resolve_executable_dir(const char *path);
 extern const char *git_exec_path(void);
 extern void setup_path(void);
 extern const char **prepare_git_cmd(struct argv_array *out, const char **argv);
diff --git a/fast-import.c b/fast-import.c
index 05d1079..4d55910 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -973,7 +973,7 @@
 		struct tag *t;
 
 		close_pack_windows(pack_data);
-		hashclose(pack_file, cur_pack_oid.hash, 0);
+		finalize_hashfile(pack_file, cur_pack_oid.hash, 0);
 		fixup_pack_header_footer(pack_data->pack_fd, pack_data->sha1,
 				    pack_data->pack_name, object_count,
 				    cur_pack_oid.hash, pack_size);
@@ -1331,7 +1331,7 @@
 		 */
 		p->pack_size = pack_size + the_hash_algo->rawsz;
 	}
-	return unpack_entry(p, oe->idx.offset, &type, sizep);
+	return unpack_entry(the_repository, p, oe->idx.offset, &type, sizep);
 }
 
 static const char *get_mode(const char *str, uint16_t *modep)
@@ -1817,7 +1817,7 @@
 
 static void dump_marks(void)
 {
-	static struct lock_file mark_lock;
+	struct lock_file mark_lock = LOCK_INIT;
 	FILE *f;
 
 	if (!export_marks_file || (import_marks_file && !import_marks_file_done))
@@ -1872,7 +1872,8 @@
 			die("corrupt mark line: %s", line);
 		e = find_object(&oid);
 		if (!e) {
-			enum object_type type = oid_object_info(&oid, NULL);
+			enum object_type type = oid_object_info(the_repository,
+								&oid, NULL);
 			if (type < 0)
 				die("object not found: %s", oid_to_hex(&oid));
 			e = insert_object(&oid);
@@ -2402,7 +2403,8 @@
 		enum object_type expected = S_ISDIR(mode) ?
 						OBJ_TREE: OBJ_BLOB;
 		enum object_type type = oe ? oe->type :
-					oid_object_info(&oid, NULL);
+					oid_object_info(the_repository, &oid,
+							NULL);
 		if (type < 0)
 			die("%s not found: %s",
 					S_ISDIR(mode) ?  "Tree" : "Blob",
@@ -2563,7 +2565,8 @@
 			die("Not a blob (actually a %s): %s",
 				type_name(oe->type), command_buf.buf);
 	} else if (!is_null_oid(&oid)) {
-		enum object_type type = oid_object_info(&oid, NULL);
+		enum object_type type = oid_object_info(the_repository, &oid,
+							NULL);
 		if (type < 0)
 			die("Blob not found: %s", command_buf.buf);
 		if (type != OBJ_BLOB)
@@ -2850,7 +2853,7 @@
 	} else if (!get_oid(from, &oid)) {
 		struct object_entry *oe = find_object(&oid);
 		if (!oe) {
-			type = oid_object_info(&oid, NULL);
+			type = oid_object_info(the_repository, &oid, NULL);
 			if (type < 0)
 				die("Not a valid object: %s", from);
 		} else
@@ -3008,7 +3011,8 @@
 	unsigned long size;
 	char *buf = NULL;
 	if (!oe) {
-		enum object_type type = oid_object_info(oid, NULL);
+		enum object_type type = oid_object_info(the_repository, oid,
+							NULL);
 		if (type < 0)
 			die("object not found: %s", oid_to_hex(oid));
 		/* cache it! */
diff --git a/fetch-pack.c b/fetch-pack.c
index 4a8bad8..a320ce9 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -305,9 +305,9 @@
 #define PIPESAFE_FLUSH 32
 #define LARGE_FLUSH 16384
 
-static int next_flush(struct fetch_pack_args *args, int count)
+static int next_flush(int stateless_rpc, int count)
 {
-	if (args->stateless_rpc) {
+	if (stateless_rpc) {
 		if (count < LARGE_FLUSH)
 			count <<= 1;
 		else
@@ -470,7 +470,7 @@
 			send_request(args, fd[1], &req_buf);
 			strbuf_setlen(&req_buf, state_len);
 			flushes++;
-			flush_at = next_flush(args, count);
+			flush_at = next_flush(args->stateless_rpc, count);
 
 			/*
 			 * We keep one window "ahead" of the other side, and
@@ -1080,6 +1080,350 @@
 	return ref;
 }
 
+static void add_shallow_requests(struct strbuf *req_buf,
+				 const struct fetch_pack_args *args)
+{
+	if (is_repository_shallow())
+		write_shallow_commits(req_buf, 1, NULL);
+	if (args->depth > 0)
+		packet_buf_write(req_buf, "deepen %d", args->depth);
+	if (args->deepen_since) {
+		timestamp_t max_age = approxidate(args->deepen_since);
+		packet_buf_write(req_buf, "deepen-since %"PRItime, max_age);
+	}
+	if (args->deepen_not) {
+		int i;
+		for (i = 0; i < args->deepen_not->nr; i++) {
+			struct string_list_item *s = args->deepen_not->items + i;
+			packet_buf_write(req_buf, "deepen-not %s", s->string);
+		}
+	}
+}
+
+static void add_wants(const struct ref *wants, struct strbuf *req_buf)
+{
+	for ( ; wants ; wants = wants->next) {
+		const struct object_id *remote = &wants->old_oid;
+		const char *remote_hex;
+		struct object *o;
+
+		/*
+		 * If that object is complete (i.e. it is an ancestor of a
+		 * local ref), we tell them we have it but do not have to
+		 * tell them about its ancestors, which they already know
+		 * about.
+		 *
+		 * We use lookup_object here because we are only
+		 * interested in the case we *know* the object is
+		 * reachable and we have already scanned it.
+		 */
+		if (((o = lookup_object(remote->hash)) != NULL) &&
+		    (o->flags & COMPLETE)) {
+			continue;
+		}
+
+		remote_hex = oid_to_hex(remote);
+		packet_buf_write(req_buf, "want %s\n", remote_hex);
+	}
+}
+
+static void add_common(struct strbuf *req_buf, struct oidset *common)
+{
+	struct oidset_iter iter;
+	const struct object_id *oid;
+	oidset_iter_init(common, &iter);
+
+	while ((oid = oidset_iter_next(&iter))) {
+		packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
+	}
+}
+
+static int add_haves(struct strbuf *req_buf, int *haves_to_send, int *in_vain)
+{
+	int ret = 0;
+	int haves_added = 0;
+	const struct object_id *oid;
+
+	while ((oid = get_rev())) {
+		packet_buf_write(req_buf, "have %s\n", oid_to_hex(oid));
+		if (++haves_added >= *haves_to_send)
+			break;
+	}
+
+	*in_vain += haves_added;
+	if (!haves_added || *in_vain >= MAX_IN_VAIN) {
+		/* Send Done */
+		packet_buf_write(req_buf, "done\n");
+		ret = 1;
+	}
+
+	/* Increase haves to send on next round */
+	*haves_to_send = next_flush(1, *haves_to_send);
+
+	return ret;
+}
+
+static int send_fetch_request(int fd_out, const struct fetch_pack_args *args,
+			      const struct ref *wants, struct oidset *common,
+			      int *haves_to_send, int *in_vain)
+{
+	int ret = 0;
+	struct strbuf req_buf = STRBUF_INIT;
+
+	if (server_supports_v2("fetch", 1))
+		packet_buf_write(&req_buf, "command=fetch");
+	if (server_supports_v2("agent", 0))
+		packet_buf_write(&req_buf, "agent=%s", git_user_agent_sanitized());
+	if (args->server_options && args->server_options->nr &&
+	    server_supports_v2("server-option", 1)) {
+		int i;
+		for (i = 0; i < args->server_options->nr; i++)
+			packet_write_fmt(fd_out, "server-option=%s",
+					 args->server_options->items[i].string);
+	}
+
+	packet_buf_delim(&req_buf);
+	if (args->use_thin_pack)
+		packet_buf_write(&req_buf, "thin-pack");
+	if (args->no_progress)
+		packet_buf_write(&req_buf, "no-progress");
+	if (args->include_tag)
+		packet_buf_write(&req_buf, "include-tag");
+	if (prefer_ofs_delta)
+		packet_buf_write(&req_buf, "ofs-delta");
+
+	/* Add shallow-info and deepen request */
+	if (server_supports_feature("fetch", "shallow", 0))
+		add_shallow_requests(&req_buf, args);
+	else if (is_repository_shallow() || args->deepen)
+		die(_("Server does not support shallow requests"));
+
+	/* Add filter */
+	if (server_supports_feature("fetch", "filter", 0) &&
+	    args->filter_options.choice) {
+		print_verbose(args, _("Server supports filter"));
+		packet_buf_write(&req_buf, "filter %s",
+				 args->filter_options.filter_spec);
+	} else if (args->filter_options.choice) {
+		warning("filtering not recognized by server, ignoring");
+	}
+
+	/* add wants */
+	add_wants(wants, &req_buf);
+
+	if (args->no_dependents) {
+		packet_buf_write(&req_buf, "done");
+		ret = 1;
+	} else {
+		/* Add all of the common commits we've found in previous rounds */
+		add_common(&req_buf, common);
+
+		/* Add initial haves */
+		ret = add_haves(&req_buf, haves_to_send, in_vain);
+	}
+
+	/* Send request */
+	packet_buf_flush(&req_buf);
+	write_or_die(fd_out, req_buf.buf, req_buf.len);
+
+	strbuf_release(&req_buf);
+	return ret;
+}
+
+/*
+ * Processes a section header in a server's response and checks if it matches
+ * `section`.  If the value of `peek` is 1, the header line will be peeked (and
+ * not consumed); if 0, the line will be consumed and the function will die if
+ * the section header doesn't match what was expected.
+ */
+static int process_section_header(struct packet_reader *reader,
+				  const char *section, int peek)
+{
+	int ret;
+
+	if (packet_reader_peek(reader) != PACKET_READ_NORMAL)
+		die("error reading section header '%s'", section);
+
+	ret = !strcmp(reader->line, section);
+
+	if (!peek) {
+		if (!ret)
+			die("expected '%s', received '%s'",
+			    section, reader->line);
+		packet_reader_read(reader);
+	}
+
+	return ret;
+}
+
+static int process_acks(struct packet_reader *reader, struct oidset *common)
+{
+	/* received */
+	int received_ready = 0;
+	int received_ack = 0;
+
+	process_section_header(reader, "acknowledgments", 0);
+	while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
+		const char *arg;
+
+		if (!strcmp(reader->line, "NAK"))
+			continue;
+
+		if (skip_prefix(reader->line, "ACK ", &arg)) {
+			struct object_id oid;
+			if (!get_oid_hex(arg, &oid)) {
+				struct commit *commit;
+				oidset_insert(common, &oid);
+				commit = lookup_commit(&oid);
+				mark_common(commit, 0, 1);
+			}
+			continue;
+		}
+
+		if (!strcmp(reader->line, "ready")) {
+			clear_prio_queue(&rev_list);
+			received_ready = 1;
+			continue;
+		}
+
+		die("unexpected acknowledgment line: '%s'", reader->line);
+	}
+
+	if (reader->status != PACKET_READ_FLUSH &&
+	    reader->status != PACKET_READ_DELIM)
+		die("error processing acks: %d", reader->status);
+
+	/* return 0 if no common, 1 if there are common, or 2 if ready */
+	return received_ready ? 2 : (received_ack ? 1 : 0);
+}
+
+static void receive_shallow_info(struct fetch_pack_args *args,
+				 struct packet_reader *reader)
+{
+	process_section_header(reader, "shallow-info", 0);
+	while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
+		const char *arg;
+		struct object_id oid;
+
+		if (skip_prefix(reader->line, "shallow ", &arg)) {
+			if (get_oid_hex(arg, &oid))
+				die(_("invalid shallow line: %s"), reader->line);
+			register_shallow(&oid);
+			continue;
+		}
+		if (skip_prefix(reader->line, "unshallow ", &arg)) {
+			if (get_oid_hex(arg, &oid))
+				die(_("invalid unshallow line: %s"), reader->line);
+			if (!lookup_object(oid.hash))
+				die(_("object not found: %s"), reader->line);
+			/* make sure that it is parsed as shallow */
+			if (!parse_object(&oid))
+				die(_("error in object: %s"), reader->line);
+			if (unregister_shallow(&oid))
+				die(_("no shallow found: %s"), reader->line);
+			continue;
+		}
+		die(_("expected shallow/unshallow, got %s"), reader->line);
+	}
+
+	if (reader->status != PACKET_READ_FLUSH &&
+	    reader->status != PACKET_READ_DELIM)
+		die("error processing shallow info: %d", reader->status);
+
+	setup_alternate_shallow(&shallow_lock, &alternate_shallow_file, NULL);
+	args->deepen = 1;
+}
+
+enum fetch_state {
+	FETCH_CHECK_LOCAL = 0,
+	FETCH_SEND_REQUEST,
+	FETCH_PROCESS_ACKS,
+	FETCH_GET_PACK,
+	FETCH_DONE,
+};
+
+static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
+				    int fd[2],
+				    const struct ref *orig_ref,
+				    struct ref **sought, int nr_sought,
+				    char **pack_lockfile)
+{
+	struct ref *ref = copy_ref_list(orig_ref);
+	enum fetch_state state = FETCH_CHECK_LOCAL;
+	struct oidset common = OIDSET_INIT;
+	struct packet_reader reader;
+	int in_vain = 0;
+	int haves_to_send = INITIAL_FLUSH;
+	packet_reader_init(&reader, fd[0], NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE);
+
+	while (state != FETCH_DONE) {
+		switch (state) {
+		case FETCH_CHECK_LOCAL:
+			sort_ref_list(&ref, ref_compare_name);
+			QSORT(sought, nr_sought, cmp_ref_by_name);
+
+			/* v2 supports these by default */
+			allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
+			use_sideband = 2;
+			if (args->depth > 0 || args->deepen_since || args->deepen_not)
+				args->deepen = 1;
+
+			if (marked)
+				for_each_ref(clear_marks, NULL);
+			marked = 1;
+
+			for_each_ref(rev_list_insert_ref_oid, NULL);
+			for_each_cached_alternate(insert_one_alternate_object);
+
+			/* Filter 'ref' by 'sought' and those that aren't local */
+			if (everything_local(args, &ref, sought, nr_sought))
+				state = FETCH_DONE;
+			else
+				state = FETCH_SEND_REQUEST;
+			break;
+		case FETCH_SEND_REQUEST:
+			if (send_fetch_request(fd[1], args, ref, &common,
+					       &haves_to_send, &in_vain))
+				state = FETCH_GET_PACK;
+			else
+				state = FETCH_PROCESS_ACKS;
+			break;
+		case FETCH_PROCESS_ACKS:
+			/* Process ACKs/NAKs */
+			switch (process_acks(&reader, &common)) {
+			case 2:
+				state = FETCH_GET_PACK;
+				break;
+			case 1:
+				in_vain = 0;
+				/* fallthrough */
+			default:
+				state = FETCH_SEND_REQUEST;
+				break;
+			}
+			break;
+		case FETCH_GET_PACK:
+			/* Check for shallow-info section */
+			if (process_section_header(&reader, "shallow-info", 1))
+				receive_shallow_info(args, &reader);
+
+			/* get the pack */
+			process_section_header(&reader, "packfile", 0);
+			if (get_pack(args, fd, pack_lockfile))
+				die(_("git fetch-pack: fetch failed."));
+
+			state = FETCH_DONE;
+			break;
+		case FETCH_DONE:
+			continue;
+		}
+	}
+
+	oidset_clear(&common);
+	return ref;
+}
+
 static void fetch_pack_config(void)
 {
 	git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
@@ -1225,7 +1569,8 @@
 		       const char *dest,
 		       struct ref **sought, int nr_sought,
 		       struct oid_array *shallow,
-		       char **pack_lockfile)
+		       char **pack_lockfile,
+		       enum protocol_version version)
 {
 	struct ref *ref_cpy;
 	struct shallow_info si;
@@ -1239,8 +1584,12 @@
 		die(_("no matching remote head"));
 	}
 	prepare_shallow_info(&si, shallow);
-	ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
-				&si, pack_lockfile);
+	if (version == protocol_v2)
+		ref_cpy = do_fetch_pack_v2(args, fd, ref, sought, nr_sought,
+					   pack_lockfile);
+	else
+		ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
+					&si, pack_lockfile);
 	reprepare_packed_git(the_repository);
 	update_shallow(args, sought, nr_sought, &si);
 	clear_shallow_info(&si);
diff --git a/fetch-pack.h b/fetch-pack.h
index 3e224a1..bb45a36 100644
--- a/fetch-pack.h
+++ b/fetch-pack.h
@@ -3,6 +3,7 @@
 
 #include "string-list.h"
 #include "run-command.h"
+#include "protocol.h"
 #include "list-objects-filter-options.h"
 
 struct oid_array;
@@ -14,6 +15,7 @@
 	const char *deepen_since;
 	const struct string_list *deepen_not;
 	struct list_objects_filter_options filter_options;
+	const struct string_list *server_options;
 	unsigned deepen_relative:1;
 	unsigned quiet:1;
 	unsigned keep_pack:1;
@@ -53,7 +55,8 @@
 		       struct ref **sought,
 		       int nr_sought,
 		       struct oid_array *shallow,
-		       char **pack_lockfile);
+		       char **pack_lockfile,
+		       enum protocol_version version);
 
 /*
  * Print an appropriate error message for each sought ref that wasn't
diff --git a/fsck.c b/fsck.c
index 9218c2a..bcae2c3 100644
--- a/fsck.c
+++ b/fsck.c
@@ -10,6 +10,13 @@
 #include "utf8.h"
 #include "sha1-array.h"
 #include "decorate.h"
+#include "oidset.h"
+#include "packfile.h"
+#include "submodule-config.h"
+#include "config.h"
+
+static struct oidset gitmodules_found = OIDSET_INIT;
+static struct oidset gitmodules_done = OIDSET_INIT;
 
 #define FSCK_FATAL -1
 #define FSCK_INFO -2
@@ -44,6 +51,7 @@
 	FUNC(MISSING_TAG_ENTRY, ERROR) \
 	FUNC(MISSING_TAG_OBJECT, ERROR) \
 	FUNC(MISSING_TREE, ERROR) \
+	FUNC(MISSING_TREE_OBJECT, ERROR) \
 	FUNC(MISSING_TYPE, ERROR) \
 	FUNC(MISSING_TYPE_ENTRY, ERROR) \
 	FUNC(MULTIPLE_AUTHORS, ERROR) \
@@ -51,6 +59,11 @@
 	FUNC(TREE_NOT_SORTED, ERROR) \
 	FUNC(UNKNOWN_TYPE, ERROR) \
 	FUNC(ZERO_PADDED_DATE, ERROR) \
+	FUNC(GITMODULES_MISSING, ERROR) \
+	FUNC(GITMODULES_BLOB, ERROR) \
+	FUNC(GITMODULES_PARSE, ERROR) \
+	FUNC(GITMODULES_NAME, ERROR) \
+	FUNC(GITMODULES_SYMLINK, ERROR) \
 	/* warnings */ \
 	FUNC(BAD_FILEMODE, WARN) \
 	FUNC(EMPTY_NAME, WARN) \
@@ -396,9 +409,11 @@
 
 	name = get_object_name(options, &commit->object);
 	if (name)
-		put_object_name(options, &commit->tree->object, "%s:", name);
+		put_object_name(options, &get_commit_tree(commit)->object,
+				"%s:", name);
 
-	result = options->walk((struct object *)commit->tree, OBJ_TREE, data, options);
+	result = options->walk((struct object *)get_commit_tree(commit),
+			       OBJ_TREE, data, options);
 	if (result < 0)
 		return result;
 	res = result;
@@ -561,10 +576,18 @@
 		has_empty_name |= !*name;
 		has_dot |= !strcmp(name, ".");
 		has_dotdot |= !strcmp(name, "..");
-		has_dotgit |= (!strcmp(name, ".git") ||
-			       is_hfs_dotgit(name) ||
-			       is_ntfs_dotgit(name));
+		has_dotgit |= is_hfs_dotgit(name) || is_ntfs_dotgit(name);
 		has_zero_pad |= *(char *)desc.buffer == '0';
+
+		if (is_hfs_dotgitmodules(name) || is_ntfs_dotgitmodules(name)) {
+			if (!S_ISLNK(mode))
+				oidset_insert(&gitmodules_found, oid);
+			else
+				retval += report(options, &item->object,
+						 FSCK_MSG_GITMODULES_SYMLINK,
+						 ".gitmodules is a symbolic link");
+		}
+
 		if (update_tree_entry_gently(&desc)) {
 			retval += report(options, &item->object, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
 			break;
@@ -711,30 +734,31 @@
 static int fsck_commit_buffer(struct commit *commit, const char *buffer,
 	unsigned long size, struct fsck_options *options)
 {
-	unsigned char tree_sha1[20], sha1[20];
+	struct object_id tree_oid, oid;
 	struct commit_graft *graft;
 	unsigned parent_count, parent_line_count = 0, author_count;
 	int err;
 	const char *buffer_begin = buffer;
+	const char *p;
 
 	if (verify_headers(buffer, size, &commit->object, options))
 		return -1;
 
 	if (!skip_prefix(buffer, "tree ", &buffer))
 		return report(options, &commit->object, FSCK_MSG_MISSING_TREE, "invalid format - expected 'tree' line");
-	if (get_sha1_hex(buffer, tree_sha1) || buffer[40] != '\n') {
+	if (parse_oid_hex(buffer, &tree_oid, &p) || *p != '\n') {
 		err = report(options, &commit->object, FSCK_MSG_BAD_TREE_SHA1, "invalid 'tree' line format - bad sha1");
 		if (err)
 			return err;
 	}
-	buffer += 41;
+	buffer = p + 1;
 	while (skip_prefix(buffer, "parent ", &buffer)) {
-		if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
+		if (parse_oid_hex(buffer, &oid, &p) || *p != '\n') {
 			err = report(options, &commit->object, FSCK_MSG_BAD_PARENT_SHA1, "invalid 'parent' line format - bad sha1");
 			if (err)
 				return err;
 		}
-		buffer += 41;
+		buffer = p + 1;
 		parent_line_count++;
 	}
 	graft = lookup_commit_graft(&commit->object.oid);
@@ -772,8 +796,8 @@
 	err = fsck_ident(&buffer, &commit->object, options);
 	if (err)
 		return err;
-	if (!commit->tree) {
-		err = report(options, &commit->object, FSCK_MSG_BAD_TREE, "could not load commit's tree %s", sha1_to_hex(tree_sha1));
+	if (!get_commit_tree(commit)) {
+		err = report(options, &commit->object, FSCK_MSG_BAD_TREE, "could not load commit's tree %s", oid_to_hex(&tree_oid));
 		if (err)
 			return err;
 	}
@@ -799,11 +823,12 @@
 static int fsck_tag_buffer(struct tag *tag, const char *data,
 	unsigned long size, struct fsck_options *options)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 	int ret = 0;
 	const char *buffer;
 	char *to_free = NULL, *eol;
 	struct strbuf sb = STRBUF_INIT;
+	const char *p;
 
 	if (data)
 		buffer = data;
@@ -834,12 +859,12 @@
 		ret = report(options, &tag->object, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
 		goto done;
 	}
-	if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n') {
+	if (parse_oid_hex(buffer, &oid, &p) || *p != '\n') {
 		ret = report(options, &tag->object, FSCK_MSG_BAD_OBJECT_SHA1, "invalid 'object' line format - bad sha1");
 		if (ret)
 			goto done;
 	}
-	buffer += 41;
+	buffer = p + 1;
 
 	if (!skip_prefix(buffer, "type ", &buffer)) {
 		ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");
@@ -901,6 +926,66 @@
 	return fsck_tag_buffer(tag, data, size, options);
 }
 
+struct fsck_gitmodules_data {
+	struct object *obj;
+	struct fsck_options *options;
+	int ret;
+};
+
+static int fsck_gitmodules_fn(const char *var, const char *value, void *vdata)
+{
+	struct fsck_gitmodules_data *data = vdata;
+	const char *subsection, *key;
+	int subsection_len;
+	char *name;
+
+	if (parse_config_key(var, "submodule", &subsection, &subsection_len, &key) < 0 ||
+	    !subsection)
+		return 0;
+
+	name = xmemdupz(subsection, subsection_len);
+	if (check_submodule_name(name) < 0)
+		data->ret |= report(data->options, data->obj,
+				    FSCK_MSG_GITMODULES_NAME,
+				    "disallowed submodule name: %s",
+				    name);
+	free(name);
+
+	return 0;
+}
+
+static int fsck_blob(struct blob *blob, const char *buf,
+		     unsigned long size, struct fsck_options *options)
+{
+	struct fsck_gitmodules_data data;
+
+	if (!oidset_contains(&gitmodules_found, &blob->object.oid))
+		return 0;
+	oidset_insert(&gitmodules_done, &blob->object.oid);
+
+	if (!buf) {
+		/*
+		 * A missing buffer here is a sign that the caller found the
+		 * blob too gigantic to load into memory. Let's just consider
+		 * that an error.
+		 */
+		return report(options, &blob->object,
+			      FSCK_MSG_GITMODULES_PARSE,
+			      ".gitmodules too large to parse");
+	}
+
+	data.obj = &blob->object;
+	data.options = options;
+	data.ret = 0;
+	if (git_config_from_mem(fsck_gitmodules_fn, CONFIG_ORIGIN_BLOB,
+				".gitmodules", buf, size, &data))
+		data.ret |= report(options, &blob->object,
+				   FSCK_MSG_GITMODULES_PARSE,
+				   "could not parse gitmodules blob");
+
+	return data.ret;
+}
+
 int fsck_object(struct object *obj, void *data, unsigned long size,
 	struct fsck_options *options)
 {
@@ -908,7 +993,7 @@
 		return report(options, obj, FSCK_MSG_BAD_OBJECT_SHA1, "no valid object to fsck");
 
 	if (obj->type == OBJ_BLOB)
-		return 0;
+		return fsck_blob((struct blob *)obj, data, size, options);
 	if (obj->type == OBJ_TREE)
 		return fsck_tree((struct tree *) obj, options);
 	if (obj->type == OBJ_COMMIT)
@@ -932,3 +1017,52 @@
 	error("object %s: %s", describe_object(o, obj), message);
 	return 1;
 }
+
+int fsck_finish(struct fsck_options *options)
+{
+	int ret = 0;
+	struct oidset_iter iter;
+	const struct object_id *oid;
+
+	oidset_iter_init(&gitmodules_found, &iter);
+	while ((oid = oidset_iter_next(&iter))) {
+		struct blob *blob;
+		enum object_type type;
+		unsigned long size;
+		char *buf;
+
+		if (oidset_contains(&gitmodules_done, oid))
+			continue;
+
+		blob = lookup_blob(oid);
+		if (!blob) {
+			ret |= report(options, &blob->object,
+				      FSCK_MSG_GITMODULES_BLOB,
+				      "non-blob found at .gitmodules");
+			continue;
+		}
+
+		buf = read_object_file(oid, &type, &size);
+		if (!buf) {
+			if (is_promisor_object(&blob->object.oid))
+				continue;
+			ret |= report(options, &blob->object,
+				      FSCK_MSG_GITMODULES_MISSING,
+				      "unable to read .gitmodules blob");
+			continue;
+		}
+
+		if (type == OBJ_BLOB)
+			ret |= fsck_blob(blob, buf, size, options);
+		else
+			ret |= report(options, &blob->object,
+				      FSCK_MSG_GITMODULES_BLOB,
+				      "non-blob found at .gitmodules");
+		free(buf);
+	}
+
+
+	oidset_clear(&gitmodules_found);
+	oidset_clear(&gitmodules_done);
+	return ret;
+}
diff --git a/fsck.h b/fsck.h
index 4525510..c3cf5e0 100644
--- a/fsck.h
+++ b/fsck.h
@@ -53,4 +53,11 @@
 int fsck_object(struct object *obj, void *data, unsigned long size,
 	struct fsck_options *options);
 
+/*
+ * Some fsck checks are context-dependent, and may end up queued; run this
+ * after completing all fsck_object() calls in order to resolve any remaining
+ * checks.
+ */
+int fsck_finish(struct fsck_options *options);
+
 #endif
diff --git a/fsmonitor.c b/fsmonitor.c
index ed3d1a0..665bd2d 100644
--- a/fsmonitor.c
+++ b/fsmonitor.c
@@ -97,19 +97,13 @@
 static int query_fsmonitor(int version, uint64_t last_update, struct strbuf *query_result)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
-	char ver[64];
-	char date[64];
-	const char *argv[4];
 
-	if (!(argv[0] = core_fsmonitor))
+	if (!core_fsmonitor)
 		return -1;
 
-	snprintf(ver, sizeof(ver), "%d", version);
-	snprintf(date, sizeof(date), "%" PRIuMAX, (uintmax_t)last_update);
-	argv[1] = ver;
-	argv[2] = date;
-	argv[3] = NULL;
-	cp.argv = argv;
+	argv_array_push(&cp.args, core_fsmonitor);
+	argv_array_pushf(&cp.args, "%d", version);
+	argv_array_pushf(&cp.args, "%" PRIuMAX, (uintmax_t)last_update);
 	cp.use_shell = 1;
 	cp.dir = get_git_work_tree();
 
diff --git a/generate-cmdlist.sh b/generate-cmdlist.sh
index eeea4b6..8d6d8b4 100755
--- a/generate-cmdlist.sh
+++ b/generate-cmdlist.sh
@@ -1,50 +1,90 @@
 #!/bin/sh
 
-echo "/* Automatically generated by generate-cmdlist.sh */
-struct cmdname_help {
-	char name[16];
-	char help[80];
-	unsigned char group;
-};
+die () {
+	echo "$@" >&2
+	exit 1
+}
 
-static const char *common_cmd_groups[] = {"
+command_list () {
+	grep -v '^#' "$1"
+}
 
-grps=grps$$.tmp
-match=match$$.tmp
-trap "rm -f '$grps' '$match'" 0 1 2 3 15
+get_categories () {
+	tr ' ' '\n'|
+	grep -v '^$' |
+	sort |
+	uniq
+}
 
-sed -n '
-	1,/^### common groups/b
-	/^### command list/q
-	/^#/b
-	/^[ 	]*$/b
-	h;s/^[^ 	][^ 	]*[ 	][ 	]*\(.*\)/	N_("\1"),/p
-	g;s/^\([^ 	][^ 	]*\)[ 	].*/\1/w '$grps'
-	' "$1"
-printf '};\n\n'
+category_list () {
+	command_list "$1" |
+	cut -c 40- |
+	get_categories
+}
 
-n=0
-substnum=
-while read grp
-do
-	echo "^git-..*[ 	]$grp"
-	substnum="$substnum${substnum:+;}s/[ 	]$grp/$n/"
-	n=$(($n+1))
-done <"$grps" >"$match"
-
-printf 'static struct cmdname_help common_cmds[] = {\n'
-grep -f "$match" "$1" |
-sed 's/^git-//' |
-sort |
-while read cmd tags
-do
-	tag=$(echo "$tags" | sed "$substnum; s/[^0-9]//g")
+get_synopsis () {
 	sed -n '
-		/^NAME/,/git-'"$cmd"'/H
+		/^NAME/,/'"$1"'/H
 		${
 			x
-			s/.*git-'"$cmd"' - \(.*\)/	{"'"$cmd"'", N_("\1"), '$tag'},/
+			s/.*'"$1"' - \(.*\)/N_("\1")/
 			p
-		}' "Documentation/git-$cmd.txt"
-done
-echo "};"
+		}' "Documentation/$1.txt"
+}
+
+define_categories () {
+	echo
+	echo "/* Command categories */"
+	bit=0
+	category_list "$1" |
+	while read cat
+	do
+		echo "#define CAT_$cat (1UL << $bit)"
+		bit=$(($bit+1))
+	done
+	test "$bit" -gt 32 && die "Urgh.. too many categories?"
+}
+
+define_category_names () {
+	echo
+	echo "/* Category names */"
+	echo "static const char *category_names[] = {"
+	bit=0
+	category_list "$1" |
+	while read cat
+	do
+		echo "	\"$cat\", /* (1UL << $bit) */"
+		bit=$(($bit+1))
+	done
+	echo "	NULL"
+	echo "};"
+}
+
+print_command_list () {
+	echo "static struct cmdname_help command_list[] = {"
+
+	command_list "$1" |
+	while read cmd rest
+	do
+		printf "	{ \"$cmd\", $(get_synopsis $cmd), 0"
+		for cat in $(echo "$rest" | get_categories)
+		do
+			printf " | CAT_$cat"
+		done
+		echo " },"
+	done
+	echo "};"
+}
+
+echo "/* Automatically generated by generate-cmdlist.sh */
+struct cmdname_help {
+	const char *name;
+	const char *help;
+	uint32_t category;
+};
+"
+define_categories "$1"
+echo
+define_category_names "$1"
+echo
+print_command_list "$1"
diff --git a/gettext.c b/gettext.c
index db727ea..7272771 100644
--- a/gettext.c
+++ b/gettext.c
@@ -2,7 +2,8 @@
  * Copyright (c) 2010 Ævar Arnfjörð Bjarmason
  */
 
-#include "git-compat-util.h"
+#include "cache.h"
+#include "exec-cmd.h"
 #include "gettext.h"
 #include "strbuf.h"
 #include "utf8.h"
@@ -157,15 +158,24 @@
 
 void git_setup_gettext(void)
 {
-	const char *podir = getenv("GIT_TEXTDOMAINDIR");
+	const char *podir = getenv(GIT_TEXT_DOMAIN_DIR_ENVIRONMENT);
+	char *p = NULL;
 
 	if (!podir)
-		podir = GIT_LOCALE_PATH;
+		podir = p = system_path(GIT_LOCALE_PATH);
+
+	if (!is_directory(podir)) {
+		free(p);
+		return;
+	}
+
 	bindtextdomain("git", podir);
 	setlocale(LC_MESSAGES, "");
 	setlocale(LC_TIME, "");
 	init_gettext_charset("git");
 	textdomain("git");
+
+	free(p);
 }
 
 /* return the number of columns of string 's' in current locale */
diff --git a/git-add--interactive.perl b/git-add--interactive.perl
index c1f52e4..36f38ce 100755
--- a/git-add--interactive.perl
+++ b/git-add--interactive.perl
@@ -205,8 +205,15 @@
 	}
 }
 
-sub get_empty_tree {
-	return '4b825dc642cb6eb9a060e54bf8d69288fbee4904';
+{
+	my $empty_tree;
+	sub get_empty_tree {
+		return $empty_tree if defined $empty_tree;
+
+		$empty_tree = run_cmd_pipe(qw(git hash-object -t tree /dev/null));
+		chomp $empty_tree;
+		return $empty_tree;
+	}
 }
 
 sub get_diff_reference {
diff --git a/git-compat-util.h b/git-compat-util.h
index 07e3832..9a64998 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -284,6 +284,10 @@
 #include <openssl/err.h>
 #endif
 
+#ifdef HAVE_SYSINFO
+# include <sys/sysinfo.h>
+#endif
+
 /* On most systems <netdb.h> would have given us this, but
  * not on some systems (e.g. z/OS).
  */
@@ -455,6 +459,7 @@
 extern void set_die_is_recursing_routine(int (*routine)(void));
 
 extern int starts_with(const char *str, const char *prefix);
+extern int istarts_with(const char *str, const char *prefix);
 
 /*
  * If the string "str" begins with the string found in "prefix", return 1.
@@ -1001,6 +1006,23 @@
 		return (x & 0x20) == 0;
 }
 
+/*
+ * Like skip_prefix, but compare case-insensitively. Note that the comparison
+ * is done via tolower(), so it is strictly ASCII (no multi-byte characters or
+ * locale-specific conversions).
+ */
+static inline int skip_iprefix(const char *str, const char *prefix,
+			       const char **out)
+{
+	do {
+		if (!*prefix) {
+			*out = str;
+			return 1;
+		}
+	} while (tolower(*str++) == tolower(*prefix++));
+	return 0;
+}
+
 static inline int strtoul_ui(char const *s, int base, unsigned int *result)
 {
 	unsigned long ul;
@@ -1052,7 +1074,7 @@
 
 #define QSORT_S(base, n, compar, ctx) do {			\
 	if (qsort_s((base), (n), sizeof(*(base)), compar, ctx))	\
-		die("BUG: qsort_s() failed");			\
+		BUG("qsort_s() failed");			\
 } while (0)
 
 #ifndef REG_STARTEND
@@ -1111,6 +1133,9 @@
 #define HAVE_VARIADIC_MACROS 1
 #endif
 
+/* usage.c: only to be used for testing BUG() implementation (see test-tool) */
+extern int BUG_exit_code;
+
 #ifdef HAVE_VARIADIC_MACROS
 __attribute__((format (printf, 3, 4))) NORETURN
 void BUG_fl(const char *file, int line, const char *fmt, ...);
diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 64f2154..ccceaf1 100755
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -11,6 +11,8 @@
 # The following functions will also be available in the commit filter:
 
 functions=$(cat << \EOF
+EMPTY_TREE=$(git hash-object -t tree /dev/null)
+
 warn () {
 	echo "$*" >&2
 }
@@ -46,7 +48,7 @@
 {
 	if test $# = 3 && test "$1" = $(git rev-parse "$3^{tree}"); then
 		map "$3"
-	elif test $# = 1 && test "$1" = 4b825dc642cb6eb9a060e54bf8d69288fbee4904; then
+	elif test $# = 1 && test "$1" = $EMPTY_TREE; then
 		:
 	else
 		git commit-tree "$@"
diff --git a/git-merge-one-file.sh b/git-merge-one-file.sh
index 9879c59..f6d9852 100755
--- a/git-merge-one-file.sh
+++ b/git-merge-one-file.sh
@@ -120,7 +120,7 @@
 	case "$1" in
 	'')
 		echo "Added $4 in both, but differently."
-		orig=$(git unpack-file e69de29bb2d1d6434b8b29ae775ad8c2e48c5391)
+		orig=$(git unpack-file $(git hash-object /dev/null))
 		;;
 	*)
 		echo "Auto-merging $4"
diff --git a/git-p4.py b/git-p4.py
index 7bb9cad..18bdd42 100755
--- a/git-p4.py
+++ b/git-p4.py
@@ -316,12 +316,17 @@
     results = p4CmdList(["changes", "-m", "1"], skip_info=True)
     return int(results[0]['change'])
 
-def p4_describe(change):
+def p4_describe(change, shelved=False):
     """Make sure it returns a valid result by checking for
        the presence of field "time".  Return a dict of the
        results."""
 
-    ds = p4CmdList(["describe", "-s", str(change)], skip_info=True)
+    cmd = ["describe", "-s"]
+    if shelved:
+        cmd += ["-S"]
+    cmd += [str(change)]
+
+    ds = p4CmdList(cmd, skip_info=True)
     if len(ds) != 1:
         die("p4 describe -s %d did not return 1 result: %s" % (change, str(ds)))
 
@@ -662,6 +667,12 @@
                             stderr=subprocess.PIPE, stdout=subprocess.PIPE);
     return proc.wait() == 0;
 
+def gitUpdateRef(ref, newvalue):
+    subprocess.check_call(["git", "update-ref", ref, newvalue])
+
+def gitDeleteRef(ref):
+    subprocess.check_call(["git", "update-ref", "-d", ref])
+
 _gitConfig = {}
 
 def gitConfig(key, typeSpecifier=None):
@@ -2099,11 +2110,11 @@
 
         commits = []
         if self.master:
-            commitish = self.master
+            committish = self.master
         else:
-            commitish = 'HEAD'
+            committish = 'HEAD'
 
-        for line in read_pipe_lines(["git", "rev-list", "--no-merges", "%s..%s" % (self.origin, commitish)]):
+        for line in read_pipe_lines(["git", "rev-list", "--no-merges", "%s..%s" % (self.origin, committish)]):
             commits.append(line.strip())
         commits.reverse()
 
@@ -2411,6 +2422,7 @@
         self.tempBranches = []
         self.tempBranchLocation = "refs/git-p4-tmp"
         self.largeFileSystem = None
+        self.suppress_meta_comment = False
 
         if gitConfig('git-p4.largeFileSystem'):
             largeFileSystemConstructor = globals()[gitConfig('git-p4.largeFileSystem')]
@@ -2421,6 +2433,18 @@
         if gitConfig("git-p4.syncFromOrigin") == "false":
             self.syncWithOrigin = False
 
+        self.depotPaths = []
+        self.changeRange = ""
+        self.previousDepotPaths = []
+        self.hasOrigin = False
+
+        # map from branch depot path to parent branch
+        self.knownBranches = {}
+        self.initialParents = {}
+
+        self.tz = "%+03d%02d" % (- time.timezone / 3600, ((- time.timezone % 3600) / 60))
+        self.labels = {}
+
     # Force a checkpoint in fast-import and wait for it to finish
     def checkpoint(self):
         self.gitStream.write("checkpoint\n\n")
@@ -2429,7 +2453,20 @@
         if self.verbose:
             print "checkpoint finished: " + out
 
-    def extractFilesFromCommit(self, commit):
+    def cmp_shelved(self, path, filerev, revision):
+        """ Determine if a path at revision #filerev is the same as the file
+            at revision @revision for a shelved changelist. If they don't match,
+            unshelving won't be safe (we will get other changes mixed in).
+
+            This is comparing the revision that the shelved changelist is *based* on, not
+            the shelved changelist itself.
+        """
+        ret = p4Cmd(["diff2", "{0}#{1}".format(path, filerev), "{0}@{1}".format(path, revision)])
+        if verbose:
+            print("p4 diff2 path %s filerev %s revision %s => %s" % (path, filerev, revision, ret))
+        return ret["status"] == "identical"
+
+    def extractFilesFromCommit(self, commit, shelved=False, shelved_cl = 0, origin_revision = 0):
         self.cloneExclude = [re.sub(r"\.\.\.$", "", path)
                              for path in self.cloneExclude]
         files = []
@@ -2452,6 +2489,19 @@
             file["rev"] = commit["rev%s" % fnum]
             file["action"] = commit["action%s" % fnum]
             file["type"] = commit["type%s" % fnum]
+            if shelved:
+                file["shelved_cl"] = int(shelved_cl)
+
+                # For shelved changelists, check that the revision of each file that the
+                # shelve was based on matches the revision that we are using for the
+                # starting point for git-fast-import (self.initialParent). Otherwise
+                # the resulting diff will contain deltas from multiple commits.
+
+                if file["action"] != "add" and \
+                    not self.cmp_shelved(path, file["rev"], origin_revision):
+                    sys.exit("change {0} not based on {1} for {2}, cannot unshelve".format(
+                        commit["change"], self.initialParent, path))
+
             files.append(file)
             fnum = fnum + 1
         return files
@@ -2743,7 +2793,16 @@
             def streamP4FilesCbSelf(entry):
                 self.streamP4FilesCb(entry)
 
-            fileArgs = ['%s#%s' % (f['path'], f['rev']) for f in filesToRead]
+            fileArgs = []
+            for f in filesToRead:
+                if 'shelved_cl' in f:
+                    # Handle shelved CLs using the "p4 print file@=N" syntax to print
+                    # the contents
+                    fileArg = '%s@=%d' % (f['path'], f['shelved_cl'])
+                else:
+                    fileArg = '%s#%s' % (f['path'], f['rev'])
+
+                fileArgs.append(fileArg)
 
             p4CmdList(["-x", "-", "print"],
                       stdin=fileArgs,
@@ -2844,11 +2903,15 @@
         self.gitStream.write(details["desc"])
         if len(jobs) > 0:
             self.gitStream.write("\nJobs: %s" % (' '.join(jobs)))
-        self.gitStream.write("\n[git-p4: depot-paths = \"%s\": change = %s" %
-                             (','.join(self.branchPrefixes), details["change"]))
-        if len(details['options']) > 0:
-            self.gitStream.write(": options = %s" % details['options'])
-        self.gitStream.write("]\nEOT\n\n")
+
+        if not self.suppress_meta_comment:
+            self.gitStream.write("\n[git-p4: depot-paths = \"%s\": change = %s" %
+                                (','.join(self.branchPrefixes), details["change"]))
+            if len(details['options']) > 0:
+                self.gitStream.write(": options = %s" % details['options'])
+            self.gitStream.write("]\n")
+
+        self.gitStream.write("EOT\n\n")
 
         if len(parent) > 0:
             if self.verbose:
@@ -3162,10 +3225,10 @@
         else:
             return None
 
-    def importChanges(self, changes):
+    def importChanges(self, changes, shelved=False, origin_revision=0):
         cnt = 1
         for change in changes:
-            description = p4_describe(change)
+            description = p4_describe(change, shelved)
             self.updateOptionDict(description)
 
             if not self.silent:
@@ -3235,7 +3298,7 @@
                                 print "Parent of %s not found. Committing into head of %s" % (branch, parent)
                             self.commit(description, filesForCommit, branch, parent)
                 else:
-                    files = self.extractFilesFromCommit(description)
+                    files = self.extractFilesFromCommit(description, shelved, change, origin_revision)
                     self.commit(description, files, self.branch,
                                 self.initialParent)
                     # only needed once, to connect to the previous commit
@@ -3300,17 +3363,23 @@
             print "IO error with git fast-import. Is your git version recent enough?"
             print self.gitError.read()
 
+    def openStreams(self):
+        self.importProcess = subprocess.Popen(["git", "fast-import"],
+                                              stdin=subprocess.PIPE,
+                                              stdout=subprocess.PIPE,
+                                              stderr=subprocess.PIPE);
+        self.gitOutput = self.importProcess.stdout
+        self.gitStream = self.importProcess.stdin
+        self.gitError = self.importProcess.stderr
+
+    def closeStreams(self):
+        self.gitStream.close()
+        if self.importProcess.wait() != 0:
+            die("fast-import failed: %s" % self.gitError.read())
+        self.gitOutput.close()
+        self.gitError.close()
 
     def run(self, args):
-        self.depotPaths = []
-        self.changeRange = ""
-        self.previousDepotPaths = []
-        self.hasOrigin = False
-
-        # map from branch depot path to parent branch
-        self.knownBranches = {}
-        self.initialParents = {}
-
         if self.importIntoRemotes:
             self.refPrefix = "refs/remotes/p4/"
         else:
@@ -3497,15 +3566,7 @@
                     b = b[len(self.projectName):]
                 self.createdBranches.add(b)
 
-        self.tz = "%+03d%02d" % (- time.timezone / 3600, ((- time.timezone % 3600) / 60))
-
-        self.importProcess = subprocess.Popen(["git", "fast-import"],
-                                              stdin=subprocess.PIPE,
-                                              stdout=subprocess.PIPE,
-                                              stderr=subprocess.PIPE);
-        self.gitOutput = self.importProcess.stdout
-        self.gitStream = self.importProcess.stdin
-        self.gitError = self.importProcess.stderr
+        self.openStreams()
 
         if revision:
             self.importHeadRevision(revision)
@@ -3585,11 +3646,7 @@
             missingP4Labels = p4Labels - gitTags
             self.importP4Labels(self.gitStream, missingP4Labels)
 
-        self.gitStream.close()
-        if self.importProcess.wait() != 0:
-            die("fast-import failed: %s" % self.gitError.read())
-        self.gitOutput.close()
-        self.gitError.close()
+        self.closeStreams()
 
         # Cleanup temporary branches created during import
         if self.tempBranches != []:
@@ -3721,6 +3778,89 @@
 
         return True
 
+class P4Unshelve(Command):
+    def __init__(self):
+        Command.__init__(self)
+        self.options = []
+        self.origin = "HEAD"
+        self.description = "Unshelve a P4 changelist into a git commit"
+        self.usage = "usage: %prog [options] changelist"
+        self.options += [
+                optparse.make_option("--origin", dest="origin",
+                    help="Use this base revision instead of the default (%s)" % self.origin),
+        ]
+        self.verbose = False
+        self.noCommit = False
+        self.destbranch = "refs/remotes/p4/unshelved"
+
+    def renameBranch(self, branch_name):
+        """ Rename the existing branch to branch_name.N
+        """
+
+        found = True
+        for i in range(0,1000):
+            backup_branch_name = "{0}.{1}".format(branch_name, i)
+            if not gitBranchExists(backup_branch_name):
+                gitUpdateRef(backup_branch_name, branch_name) # copy ref to backup
+                gitDeleteRef(branch_name)
+                found = True
+                print("renamed old unshelve branch to {0}".format(backup_branch_name))
+                break
+
+        if not found:
+            sys.exit("gave up trying to rename existing branch {0}".format(sync.branch))
+
+    def findLastP4Revision(self, starting_point):
+        """ Look back from starting_point for the first commit created by git-p4
+            to find the P4 commit we are based on, and the depot-paths.
+        """
+
+        for parent in (range(65535)):
+            log = extractLogMessageFromGitCommit("{0}^{1}".format(starting_point, parent))
+            settings = extractSettingsGitLog(log)
+            if settings.has_key('change'):
+                return settings
+
+        sys.exit("could not find git-p4 commits in {0}".format(self.origin))
+
+    def run(self, args):
+        if len(args) != 1:
+            return False
+
+        if not gitBranchExists(self.origin):
+            sys.exit("origin branch {0} does not exist".format(self.origin))
+
+        sync = P4Sync()
+        changes = args
+        sync.initialParent = self.origin
+
+        # use the first change in the list to construct the branch to unshelve into
+        change = changes[0]
+
+        # if the target branch already exists, rename it
+        branch_name = "{0}/{1}".format(self.destbranch, change)
+        if gitBranchExists(branch_name):
+            self.renameBranch(branch_name)
+        sync.branch = branch_name
+
+        sync.verbose = self.verbose
+        sync.suppress_meta_comment = True
+
+        settings = self.findLastP4Revision(self.origin)
+        origin_revision = settings['change']
+        sync.depotPaths = settings['depot-paths']
+        sync.branchPrefixes = sync.depotPaths
+
+        sync.openStreams()
+        sync.loadUserMapFromCache()
+        sync.silent = True
+        sync.importChanges(changes, shelved=True, origin_revision=origin_revision)
+        sync.closeStreams()
+
+        print("unshelved changelist {0} into {1}".format(change, branch_name))
+
+        return True
+
 class P4Branches(Command):
     def __init__(self):
         Command.__init__(self)
@@ -3775,7 +3915,8 @@
     "rebase" : P4Rebase,
     "clone" : P4Clone,
     "rollback" : P4RollBack,
-    "branches" : P4Branches
+    "branches" : P4Branches,
+    "unshelve" : P4Unshelve,
 }
 
 
diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index 85a72b9..06a7b79 100644
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -81,6 +81,8 @@
 # and leaves CR at the end instead.
 cr=$(printf "\015")
 
+empty_tree=$(git hash-object -t tree /dev/null)
+
 strategy_args=${strategy:+--strategy=$strategy}
 test -n "$strategy_opts" &&
 eval '
@@ -244,7 +246,7 @@
 		die "$(eval_gettext "\$sha1: not a commit that can be picked")"
 	}
 	ptree=$(git rev-parse -q --verify "$1"^^{tree} 2>/dev/null) ||
-		ptree=4b825dc642cb6eb9a060e54bf8d69288fbee4904
+		ptree=$empty_tree
 	test "$tree" = "$ptree"
 }
 
@@ -894,6 +896,8 @@
 	else
 		revisions=$onto...$orig_head
 		shortrevisions=$shorthead
+		test -z "$squash_onto" ||
+		echo "$squash_onto" >"$state_dir"/squash-onto
 	fi
 }
 
@@ -948,7 +952,7 @@
 	die "Could not skip unnecessary pick commands"
 
 	checkout_onto
-	if test -z "$rebase_root" && test ! -d "$rewritten"
+	if test ! -d "$rewritten"
 	then
 		require_clean_work_tree "rebase"
 		exec git rebase--helper ${force_rebase:+--no-ff} $allow_empty_message \
diff --git a/git-send-email.perl b/git-send-email.perl
index 2fa7818..8ec70e5 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -1330,9 +1330,14 @@
 	return File::Spec::Functions::file_name_is_absolute($path);
 }
 
-# Returns 1 if the message was sent, and 0 otherwise.
-# In actuality, the whole program dies when there
-# is an error sending a message.
+# Prepares the email, then asks the user what to do.
+#
+# If the user chooses to send the email, it's sent and 1 is returned.
+# If the user chooses not to send the email, 0 is returned.
+# If the user decides they want to make further edits, -1 is returned and the
+# caller is expected to call send_message again after the edits are performed.
+#
+# If an error occurs sending the email, this just dies.
 
 sub send_message {
 	my @recipients = unique_email_list(@to);
@@ -1404,15 +1409,17 @@
 
 EOF
 		}
-		# TRANSLATORS: Make sure to include [y] [n] [q] [a] in your
+		# TRANSLATORS: Make sure to include [y] [n] [e] [q] [a] in your
 		# translation. The program will only accept English input
 		# at this point.
-		$_ = ask(__("Send this email? ([y]es|[n]o|[q]uit|[a]ll): "),
-		         valid_re => qr/^(?:yes|y|no|n|quit|q|all|a)/i,
+		$_ = ask(__("Send this email? ([y]es|[n]o|[e]dit|[q]uit|[a]ll): "),
+		         valid_re => qr/^(?:yes|y|no|n|edit|e|quit|q|all|a)/i,
 		         default => $ask_default);
 		die __("Send this email reply required") unless defined $_;
 		if (/^n/i) {
 			return 0;
+		} elsif (/^e/i) {
+			return -1;
 		} elsif (/^q/i) {
 			cleanup_compose_files();
 			exit(0);
@@ -1552,7 +1559,12 @@
 $subject = $initial_subject;
 $message_num = 0;
 
-foreach my $t (@files) {
+# Prepares the email, prompts the user, sends it out
+# Returns 0 if an edit was done and the function should be called again, or 1
+# otherwise.
+sub process_file {
+	my ($t) = @_;
+
 	open my $fh, "<", $t or die sprintf(__("can't open file %s"), $t);
 
 	my $author = undef;
@@ -1642,10 +1654,15 @@
 			elsif (/^Content-Transfer-Encoding: (.*)/i) {
 				$xfer_encoding = $1 if not defined $xfer_encoding;
 			}
+			elsif (/^In-Reply-To: (.*)/i) {
+				$in_reply_to = $1;
+			}
+			elsif (/^References: (.*)/i) {
+				$references = $1;
+			}
 			elsif (!/^Date:\s/i && /^[-A-Za-z]+:\s+\S/) {
 				push @xh, $_;
 			}
-
 		} else {
 			# In the traditional
 			# "send lots of email" format,
@@ -1755,6 +1772,10 @@
 	}
 
 	my $message_was_sent = send_message();
+	if ($message_was_sent == -1) {
+		do_edit($t);
+		return 0;
+	}
 
 	# set up for the next message
 	if ($thread && $message_was_sent &&
@@ -1776,6 +1797,14 @@
 		undef $auth;
 		sleep($relogin_delay) if defined $relogin_delay;
 	}
+
+	return 1;
+}
+
+foreach my $t (@files) {
+	while (!process_file($t)) {
+		# user edited the file
+	}
 }
 
 # Execute a command (e.g. $to_cmd) to get a list of email addresses
diff --git a/git-submodule.sh b/git-submodule.sh
index 2491496..78073cd 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -42,6 +42,7 @@
 custom_name=
 depth=
 progress=
+dissociate=
 
 die_if_unmatched ()
 {
@@ -117,6 +118,9 @@
 		-q|--quiet)
 			GIT_QUIET=1
 			;;
+		--progress)
+			progress=1
+			;;
 		--reference)
 			case "$2" in '') usage ;; esac
 			reference_path=$2
@@ -125,6 +129,9 @@
 		--reference=*)
 			reference_path="${1#--reference=}"
 			;;
+		--dissociate)
+			dissociate=1
+			;;
 		--name)
 			case "$2" in '') usage ;; esac
 			custom_name=$2
@@ -229,6 +236,11 @@
 		sm_name="$sm_path"
 	fi
 
+	if ! git submodule--helper check-name "$sm_name"
+	then
+		die "$(eval_gettext "'$sm_name' is not a valid submodule name")"
+	fi
+
 	# perhaps the path exists and is already a git repo, else clone it
 	if test -e "$sm_path"
 	then
@@ -255,7 +267,7 @@
 				eval_gettextln "Reactivating local git directory for submodule '\$sm_name'."
 			fi
 		fi
-		git submodule--helper clone ${GIT_QUIET:+--quiet} --prefix "$wt_prefix" --path "$sm_path" --name "$sm_name" --url "$realrepo" ${reference:+"$reference"} ${depth:+"$depth"} || exit
+		git submodule--helper clone ${GIT_QUIET:+--quiet} ${progress:+"--progress"} --prefix "$wt_prefix" --path "$sm_path" --name "$sm_name" --url "$realrepo" ${reference:+"$reference"} ${dissociate:+"--dissociate"} ${depth:+"$depth"} || exit
 		(
 			sanitize_submodule_env
 			cd "$sm_path" &&
@@ -465,7 +477,7 @@
 			GIT_QUIET=1
 			;;
 		--progress)
-			progress="--progress"
+			progress=1
 			;;
 		-i|--init)
 			init=1
@@ -490,6 +502,9 @@
 		--reference=*)
 			reference="$1"
 			;;
+		--dissociate)
+			dissociate=1
+			;;
 		-m|--merge)
 			update="merge"
 			;;
@@ -542,14 +557,15 @@
 
 	{
 	git submodule--helper update-clone ${GIT_QUIET:+--quiet} \
-		${progress:+"$progress"} \
+		${progress:+"--progress"} \
 		${wt_prefix:+--prefix "$wt_prefix"} \
 		${prefix:+--recursive-prefix "$prefix"} \
 		${update:+--update "$update"} \
 		${reference:+"$reference"} \
+		${dissociate:+"--dissociate"} \
 		${depth:+--depth "$depth"} \
-		${recommend_shallow:+"$recommend_shallow"} \
-		${jobs:+$jobs} \
+		$recommend_shallow \
+		$jobs \
 		"$@" || echo "#unmatched" $?
 	} | {
 	err=
@@ -614,7 +630,7 @@
 				# is not reachable from a ref.
 				is_tip_reachable "$sm_path" "$sha1" ||
 				fetch_in_submodule "$sm_path" $depth ||
-				die "$(eval_gettext "Unable to fetch in submodule path '\$displaypath'")"
+				say "$(eval_gettext "Unable to fetch in submodule path '\$displaypath'")"
 
 				# Now we tried the usual fetch, but $sha1 may
 				# not be reachable from any of the refs
diff --git a/git.c b/git.c
index f598fae..c2f48d5 100644
--- a/git.c
+++ b/git.c
@@ -3,6 +3,7 @@
 #include "exec-cmd.h"
 #include "help.h"
 #include "run-command.h"
+#include "alias.h"
 
 #define RUN_SETUP		(1<<0)
 #define RUN_SETUP_GENTLY	(1<<1)
@@ -25,7 +26,7 @@
 const char git_usage_string[] =
 	N_("git [--version] [--help] [-C <path>] [-c <name>=<value>]\n"
 	   "           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
-	   "           [-p | --paginate | --no-pager] [--no-replace-objects] [--bare]\n"
+	   "           [-p | --paginate | -P | --no-pager] [--no-replace-objects] [--bare]\n"
 	   "           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
 	   "           <command> [<args>]");
 
@@ -36,7 +37,66 @@
 
 static int use_pager = -1;
 
-static void list_builtins(unsigned int exclude_option, char sep);
+static void list_builtins(struct string_list *list, unsigned int exclude_option);
+
+static void exclude_helpers_from_list(struct string_list *list)
+{
+	int i = 0;
+
+	while (i < list->nr) {
+		if (strstr(list->items[i].string, "--"))
+			unsorted_string_list_delete_item(list, i, 0);
+		else
+			i++;
+	}
+}
+
+static int match_token(const char *spec, int len, const char *token)
+{
+	int token_len = strlen(token);
+
+	return len == token_len && !strncmp(spec, token, token_len);
+}
+
+static int list_cmds(const char *spec)
+{
+	struct string_list list = STRING_LIST_INIT_DUP;
+	int i;
+
+	while (*spec) {
+		const char *sep = strchrnul(spec, ',');
+		int len = sep - spec;
+
+		if (match_token(spec, len, "builtins"))
+			list_builtins(&list, 0);
+		else if (match_token(spec, len, "main"))
+			list_all_main_cmds(&list);
+		else if (match_token(spec, len, "others"))
+			list_all_other_cmds(&list);
+		else if (match_token(spec, len, "nohelpers"))
+			exclude_helpers_from_list(&list);
+		else if (match_token(spec, len, "alias"))
+			list_aliases(&list);
+		else if (match_token(spec, len, "config"))
+			list_cmds_by_config(&list);
+		else if (len > 5 && !strncmp(spec, "list-", 5)) {
+			struct strbuf sb = STRBUF_INIT;
+
+			strbuf_add(&sb, spec + 5, len - 5);
+			list_cmds_by_category(&list, sb.buf);
+			strbuf_release(&sb);
+		}
+		else
+			die(_("unsupported command listing type '%s'"), spec);
+		spec += len;
+		if (*spec == ',')
+			spec++;
+	}
+	for (i = 0; i < list.nr; i++)
+		puts(list.items[i].string);
+	string_list_clear(&list, 0);
+	return 0;
+}
 
 static void commit_pager_choice(void) {
 	switch (use_pager) {
@@ -83,7 +143,7 @@
 		 */
 		if (skip_prefix(cmd, "--exec-path", &cmd)) {
 			if (*cmd == '=')
-				git_set_argv_exec_path(cmd + 1);
+				git_set_exec_path(cmd + 1);
 			else {
 				puts(git_exec_path());
 				exit(0);
@@ -99,7 +159,7 @@
 			exit(0);
 		} else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
 			use_pager = 1;
-		} else if (!strcmp(cmd, "--no-pager")) {
+		} else if (!strcmp(cmd, "-P") || !strcmp(cmd, "--no-pager")) {
 			use_pager = 0;
 			if (envchanged)
 				*envchanged = 1;
@@ -223,12 +283,19 @@
 			}
 			(*argv)++;
 			(*argc)--;
-		} else if (!strcmp(cmd, "--list-builtins")) {
-			list_builtins(0, '\n');
-			exit(0);
-		} else if (!strcmp(cmd, "--list-parseopt-builtins")) {
-			list_builtins(NO_PARSEOPT, ' ');
-			exit(0);
+		} else if (skip_prefix(cmd, "--list-cmds=", &cmd)) {
+			if (!strcmp(cmd, "parseopt")) {
+				struct string_list list = STRING_LIST_INIT_DUP;
+				int i;
+
+				list_builtins(&list, NO_PARSEOPT);
+				for (i = 0; i < list.nr; i++)
+					printf("%s ", list.items[i].string);
+				string_list_clear(&list, 0);
+				exit(0);
+			} else {
+				exit(list_cmds(cmd));
+			}
 		} else {
 			fprintf(stderr, _("unknown option: %s\n"), cmd);
 			usage(git_usage_string);
@@ -392,6 +459,7 @@
 	{ "clone", cmd_clone },
 	{ "column", cmd_column, RUN_SETUP_GENTLY },
 	{ "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
+	{ "commit-graph", cmd_commit_graph, RUN_SETUP },
 	{ "commit-tree", cmd_commit_tree, RUN_SETUP | NO_PARSEOPT },
 	{ "config", cmd_config, RUN_SETUP_GENTLY | DELAY_PAGER_CONFIG },
 	{ "count-objects", cmd_count_objects, RUN_SETUP },
@@ -465,6 +533,7 @@
 	{ "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 	{ "rm", cmd_rm, RUN_SETUP },
 	{ "send-pack", cmd_send_pack, RUN_SETUP },
+	{ "serve", cmd_serve, RUN_SETUP },
 	{ "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 	{ "show", cmd_show, RUN_SETUP },
 	{ "show-branch", cmd_show_branch, RUN_SETUP },
@@ -482,6 +551,7 @@
 	{ "update-server-info", cmd_update_server_info, RUN_SETUP },
 	{ "upload-archive", cmd_upload_archive, NO_PARSEOPT },
 	{ "upload-archive--writer", cmd_upload_archive_writer, NO_PARSEOPT },
+	{ "upload-pack", cmd_upload_pack },
 	{ "var", cmd_var, RUN_SETUP_GENTLY | NO_PARSEOPT },
 	{ "verify-commit", cmd_verify_commit, RUN_SETUP },
 	{ "verify-pack", cmd_verify_pack },
@@ -508,14 +578,14 @@
 	return !!get_builtin(s);
 }
 
-static void list_builtins(unsigned int exclude_option, char sep)
+static void list_builtins(struct string_list *out, unsigned int exclude_option)
 {
 	int i;
 	for (i = 0; i < ARRAY_SIZE(commands); i++) {
 		if (exclude_option &&
 		    (commands[i].option & exclude_option))
 			continue;
-		printf("%s%c", commands[i].cmd, sep);
+		string_list_append(out, commands[i].cmd);
 	}
 }
 
diff --git a/gpg-interface.c b/gpg-interface.c
index 4feacf1..0647bd6 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -101,22 +101,26 @@
 		fputs(output, stderr);
 }
 
-/*
- * Look at GPG signed content (e.g. a signed tag object), whose
- * payload is followed by a detached signature on it.  Return the
- * offset where the embedded detached signature begins, or the end of
- * the data when there is no such signature.
- */
-size_t parse_signature(const char *buf, unsigned long size)
+static int is_gpg_start(const char *line)
 {
-	char *eol;
+	return starts_with(line, PGP_SIGNATURE) ||
+		starts_with(line, PGP_MESSAGE);
+}
+
+size_t parse_signature(const char *buf, size_t size)
+{
 	size_t len = 0;
-	while (len < size && !starts_with(buf + len, PGP_SIGNATURE) &&
-			!starts_with(buf + len, PGP_MESSAGE)) {
+	size_t match = size;
+	while (len < size) {
+		const char *eol;
+
+		if (is_gpg_start(buf + len))
+			match = len;
+
 		eol = memchr(buf + len, '\n', size - len);
 		len += eol ? eol - (buf + len) + 1 : size - len;
 	}
-	return len;
+	return match;
 }
 
 void set_signing_key(const char *key)
@@ -128,13 +132,19 @@
 int git_gpg_config(const char *var, const char *value, void *cb)
 {
 	if (!strcmp(var, "user.signingkey")) {
+		if (!value)
+			return config_error_nonbool(var);
 		set_signing_key(value);
+		return 0;
 	}
+
 	if (!strcmp(var, "gpg.program")) {
 		if (!value)
 			return config_error_nonbool(var);
 		gpg_program = xstrdup(value);
+		return 0;
 	}
+
 	return 0;
 }
 
@@ -145,12 +155,6 @@
 	return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
 }
 
-/*
- * Create a detached signature for the contents of "buffer" and append
- * it after "signature"; "buffer" and "signature" can be the same
- * strbuf instance, which would cause the detached signature appended
- * at the end.
- */
 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
 {
 	struct child_process gpg = CHILD_PROCESS_INIT;
@@ -192,11 +196,6 @@
 	return 0;
 }
 
-/*
- * Run "gpg" to see if the payload matches the detached signature.
- * gpg_output, when set, receives the diagnostic output from GPG.
- * gpg_status, when set, receives the status output from GPG.
- */
 int verify_signed_buffer(const char *payload, size_t payload_size,
 			 const char *signature, size_t signature_size,
 			 struct strbuf *gpg_output, struct strbuf *gpg_status)
diff --git a/gpg-interface.h b/gpg-interface.h
index d2d4fd3..a5e6517 100644
--- a/gpg-interface.h
+++ b/gpg-interface.h
@@ -23,16 +23,43 @@
 	char *key;
 };
 
-extern void signature_check_clear(struct signature_check *sigc);
-extern size_t parse_signature(const char *buf, unsigned long size);
-extern void parse_gpg_output(struct signature_check *);
-extern int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key);
-extern int verify_signed_buffer(const char *payload, size_t payload_size, const char *signature, size_t signature_size, struct strbuf *gpg_output, struct strbuf *gpg_status);
-extern int git_gpg_config(const char *, const char *, void *);
-extern void set_signing_key(const char *);
-extern const char *get_signing_key(void);
-extern int check_signature(const char *payload, size_t plen,
-	const char *signature, size_t slen, struct signature_check *sigc);
-void print_signature_buffer(const struct signature_check *sigc, unsigned flags);
+void signature_check_clear(struct signature_check *sigc);
+
+/*
+ * Look at GPG signed content (e.g. a signed tag object), whose
+ * payload is followed by a detached signature on it.  Return the
+ * offset where the embedded detached signature begins, or the end of
+ * the data when there is no such signature.
+ */
+size_t parse_signature(const char *buf, size_t size);
+
+void parse_gpg_output(struct signature_check *);
+
+/*
+ * Create a detached signature for the contents of "buffer" and append
+ * it after "signature"; "buffer" and "signature" can be the same
+ * strbuf instance, which would cause the detached signature appended
+ * at the end.
+ */
+int sign_buffer(struct strbuf *buffer, struct strbuf *signature,
+		const char *signing_key);
+
+/*
+ * Run "gpg" to see if the payload matches the detached signature.
+ * gpg_output, when set, receives the diagnostic output from GPG.
+ * gpg_status, when set, receives the status output from GPG.
+ */
+int verify_signed_buffer(const char *payload, size_t payload_size,
+			 const char *signature, size_t signature_size,
+			 struct strbuf *gpg_output, struct strbuf *gpg_status);
+
+int git_gpg_config(const char *, const char *, void *);
+void set_signing_key(const char *);
+const char *get_signing_key(void);
+int check_signature(const char *payload, size_t plen,
+		    const char *signature, size_t slen,
+		    struct signature_check *sigc);
+void print_signature_buffer(const struct signature_check *sigc,
+			    unsigned flags);
 
 #endif
diff --git a/grep.c b/grep.c
index 65b90c1..45ec7e6 100644
--- a/grep.c
+++ b/grep.c
@@ -404,7 +404,7 @@
 			die("Couldn't allocate PCRE JIT stack");
 		pcre_assign_jit_stack(p->pcre1_extra_info, NULL, p->pcre1_jit_stack);
 	} else if (p->pcre1_jit_on != 0) {
-		die("BUG: The pcre1_jit_on variable should be 0 or 1, not %d",
+		BUG("The pcre1_jit_on variable should be 0 or 1, not %d",
 		    p->pcre1_jit_on);
 	}
 #endif
@@ -550,7 +550,7 @@
 			die("Couldn't allocate PCRE2 match context");
 		pcre2_jit_stack_assign(p->pcre2_match_context, NULL, p->pcre2_jit_stack);
 	} else if (p->pcre2_jit_on != 0) {
-		die("BUG: The pcre2_jit_on variable should be 0 or 1, not %d",
+		BUG("The pcre2_jit_on variable should be 0 or 1, not %d",
 		    p->pcre1_jit_on);
 	}
 }
@@ -636,7 +636,6 @@
 	if (err) {
 		char errbuf[1024];
 		regerror(err, &p->regexp, errbuf, sizeof(errbuf));
-		regfree(&p->regexp);
 		compile_regexp_failed(p, errbuf);
 	}
 }
@@ -701,7 +700,6 @@
 	if (err) {
 		char errbuf[1024];
 		regerror(err, &p->regexp, errbuf, 1024);
-		regfree(&p->regexp);
 		compile_regexp_failed(p, errbuf);
 	}
 }
@@ -917,10 +915,10 @@
 
 	for (p = opt->header_list; p; p = p->next) {
 		if (p->token != GREP_PATTERN_HEAD)
-			die("BUG: a non-header pattern in grep header list.");
+			BUG("a non-header pattern in grep header list.");
 		if (p->field < GREP_HEADER_FIELD_MIN ||
 		    GREP_HEADER_FIELD_MAX <= p->field)
-			die("BUG: unknown header field %d", p->field);
+			BUG("unknown header field %d", p->field);
 		compile_regexp(p, opt);
 	}
 
@@ -933,7 +931,7 @@
 
 		h = compile_pattern_atom(&pp);
 		if (!h || pp != p->next)
-			die("BUG: malformed header expr");
+			BUG("malformed header expr");
 		if (!header_group[p->field]) {
 			header_group[p->field] = h;
 			continue;
@@ -1652,7 +1650,7 @@
 		fill_filespec(df, &null_oid, 0, 0100644);
 		break;
 	default:
-		die("BUG: attempt to textconv something without a path?");
+		BUG("attempt to textconv something without a path?");
 	}
 
 	/*
@@ -1748,7 +1746,7 @@
 		case GREP_BINARY_TEXT:
 			break;
 		default:
-			die("BUG: unknown binary handling mode");
+			BUG("unknown binary handling mode");
 		}
 	}
 
@@ -2072,7 +2070,7 @@
 	case GREP_SOURCE_BUF:
 		return gs->buf ? 0 : -1;
 	}
-	die("BUG: invalid grep_source type to load");
+	BUG("invalid grep_source type to load");
 }
 
 void grep_source_load_driver(struct grep_source *gs)
diff --git a/help.c b/help.c
index a4feef2..dd35fcc 100644
--- a/help.c
+++ b/help.c
@@ -5,13 +5,127 @@
 #include "run-command.h"
 #include "levenshtein.h"
 #include "help.h"
-#include "common-cmds.h"
+#include "command-list.h"
 #include "string-list.h"
 #include "column.h"
 #include "version.h"
 #include "refs.h"
 #include "parse-options.h"
 
+struct category_description {
+	uint32_t category;
+	const char *desc;
+};
+static uint32_t common_mask =
+	CAT_init | CAT_worktree | CAT_info |
+	CAT_history | CAT_remote;
+static struct category_description common_categories[] = {
+	{ CAT_init, N_("start a working area (see also: git help tutorial)") },
+	{ CAT_worktree, N_("work on the current change (see also: git help everyday)") },
+	{ CAT_info, N_("examine the history and state (see also: git help revisions)") },
+	{ CAT_history, N_("grow, mark and tweak your common history") },
+	{ CAT_remote, N_("collaborate (see also: git help workflows)") },
+	{ 0, NULL }
+};
+static struct category_description main_categories[] = {
+	{ CAT_mainporcelain, N_("Main Porcelain Commands") },
+	{ CAT_ancillarymanipulators, N_("Ancillary Commands / Manipulators") },
+	{ CAT_ancillaryinterrogators, N_("Ancillary Commands / Interrogators") },
+	{ CAT_foreignscminterface, N_("Interacting with Others") },
+	{ CAT_plumbingmanipulators, N_("Low-level Commands / Manipulators") },
+	{ CAT_plumbinginterrogators, N_("Low-level Commands / Interrogators") },
+	{ CAT_synchingrepositories, N_("Low-level Commands / Synching Repositories") },
+	{ CAT_purehelpers, N_("Low-level Commands / Internal Helpers") },
+	{ 0, NULL }
+};
+
+static const char *drop_prefix(const char *name, uint32_t category)
+{
+	const char *new_name;
+
+	if (skip_prefix(name, "git-", &new_name))
+		return new_name;
+	if (category == CAT_guide && skip_prefix(name, "git", &new_name))
+		return new_name;
+	return name;
+
+}
+
+static void extract_cmds(struct cmdname_help **p_cmds, uint32_t mask)
+{
+	int i, nr = 0;
+	struct cmdname_help *cmds;
+
+	if (ARRAY_SIZE(command_list) == 0)
+		BUG("empty command_list[] is a sign of broken generate-cmdlist.sh");
+
+	ALLOC_ARRAY(cmds, ARRAY_SIZE(command_list) + 1);
+
+	for (i = 0; i < ARRAY_SIZE(command_list); i++) {
+		const struct cmdname_help *cmd = command_list + i;
+
+		if (!(cmd->category & mask))
+			continue;
+
+		cmds[nr] = *cmd;
+		cmds[nr].name = drop_prefix(cmd->name, cmd->category);
+
+		nr++;
+	}
+	cmds[nr].name = NULL;
+	*p_cmds = cmds;
+}
+
+static void print_command_list(const struct cmdname_help *cmds,
+			       uint32_t mask, int longest)
+{
+	int i;
+
+	for (i = 0; cmds[i].name; i++) {
+		if (cmds[i].category & mask) {
+			printf("   %s   ", cmds[i].name);
+			mput_char(' ', longest - strlen(cmds[i].name));
+			puts(_(cmds[i].help));
+		}
+	}
+}
+
+static int cmd_name_cmp(const void *elem1, const void *elem2)
+{
+	const struct cmdname_help *e1 = elem1;
+	const struct cmdname_help *e2 = elem2;
+
+	return strcmp(e1->name, e2->name);
+}
+
+static void print_cmd_by_category(const struct category_description *catdesc)
+{
+	struct cmdname_help *cmds;
+	int longest = 0;
+	int i, nr = 0;
+	uint32_t mask = 0;
+
+	for (i = 0; catdesc[i].desc; i++)
+		mask |= catdesc[i].category;
+
+	extract_cmds(&cmds, mask);
+
+	for (i = 0; cmds[i].name; i++, nr++) {
+		if (longest < strlen(cmds[i].name))
+			longest = strlen(cmds[i].name);
+	}
+	QSORT(cmds, nr, cmd_name_cmp);
+
+	for (i = 0; catdesc[i].desc; i++) {
+		uint32_t mask = catdesc[i].category;
+		const char *desc = catdesc[i].desc;
+
+		printf("\n%s\n", _(desc));
+		print_command_list(cmds, mask, longest);
+	}
+	free(cmds);
+}
+
 void add_cmdname(struct cmdnames *cmds, const char *name, int len)
 {
 	struct cmdname *ent;
@@ -190,42 +304,114 @@
 	}
 }
 
-static int cmd_group_cmp(const void *elem1, const void *elem2)
-{
-	const struct cmdname_help *e1 = elem1;
-	const struct cmdname_help *e2 = elem2;
-
-	if (e1->group < e2->group)
-		return -1;
-	if (e1->group > e2->group)
-		return 1;
-	return strcmp(e1->name, e2->name);
-}
-
 void list_common_cmds_help(void)
 {
-	int i, longest = 0;
-	int current_grp = -1;
-
-	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
-		if (longest < strlen(common_cmds[i].name))
-			longest = strlen(common_cmds[i].name);
-	}
-
-	QSORT(common_cmds, ARRAY_SIZE(common_cmds), cmd_group_cmp);
-
 	puts(_("These are common Git commands used in various situations:"));
+	print_cmd_by_category(common_categories);
+}
 
-	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
-		if (common_cmds[i].group != current_grp) {
-			printf("\n%s\n", _(common_cmd_groups[common_cmds[i].group]));
-			current_grp = common_cmds[i].group;
+void list_all_main_cmds(struct string_list *list)
+{
+	struct cmdnames main_cmds, other_cmds;
+	int i;
+
+	memset(&main_cmds, 0, sizeof(main_cmds));
+	memset(&other_cmds, 0, sizeof(other_cmds));
+	load_command_list("git-", &main_cmds, &other_cmds);
+
+	for (i = 0; i < main_cmds.cnt; i++)
+		string_list_append(list, main_cmds.names[i]->name);
+
+	clean_cmdnames(&main_cmds);
+	clean_cmdnames(&other_cmds);
+}
+
+void list_all_other_cmds(struct string_list *list)
+{
+	struct cmdnames main_cmds, other_cmds;
+	int i;
+
+	memset(&main_cmds, 0, sizeof(main_cmds));
+	memset(&other_cmds, 0, sizeof(other_cmds));
+	load_command_list("git-", &main_cmds, &other_cmds);
+
+	for (i = 0; i < other_cmds.cnt; i++)
+		string_list_append(list, other_cmds.names[i]->name);
+
+	clean_cmdnames(&main_cmds);
+	clean_cmdnames(&other_cmds);
+}
+
+void list_cmds_by_category(struct string_list *list,
+			   const char *cat)
+{
+	int i, n = ARRAY_SIZE(command_list);
+	uint32_t cat_id = 0;
+
+	for (i = 0; category_names[i]; i++) {
+		if (!strcmp(cat, category_names[i])) {
+			cat_id = 1UL << i;
+			break;
 		}
-
-		printf("   %s   ", common_cmds[i].name);
-		mput_char(' ', longest - strlen(common_cmds[i].name));
-		puts(_(common_cmds[i].help));
 	}
+	if (!cat_id)
+		die(_("unsupported command listing type '%s'"), cat);
+
+	for (i = 0; i < n; i++) {
+		struct cmdname_help *cmd = command_list + i;
+
+		if (!(cmd->category & cat_id))
+			continue;
+		string_list_append(list, drop_prefix(cmd->name, cmd->category));
+	}
+}
+
+void list_cmds_by_config(struct string_list *list)
+{
+	const char *cmd_list;
+
+	/*
+	 * There's no actual repository setup at this point (and even
+	 * if there is, we don't really care; only global config
+	 * matters). If we accidentally set up a repository, it's ok
+	 * too since the caller (git --list-cmds=) should exit shortly
+	 * anyway.
+	 */
+	if (git_config_get_string_const("completion.commands", &cmd_list))
+		return;
+
+	string_list_sort(list);
+	string_list_remove_duplicates(list, 0);
+
+	while (*cmd_list) {
+		struct strbuf sb = STRBUF_INIT;
+		const char *p = strchrnul(cmd_list, ' ');
+
+		strbuf_add(&sb, cmd_list, p - cmd_list);
+		if (*cmd_list == '-')
+			string_list_remove(list, cmd_list + 1, 0);
+		else
+			string_list_insert(list, sb.buf);
+		strbuf_release(&sb);
+		while (*p == ' ')
+			p++;
+		cmd_list = p;
+	}
+}
+
+void list_common_guides_help(void)
+{
+	struct category_description catdesc[] = {
+		{ CAT_guide, N_("The common Git guides are:") },
+		{ 0, NULL }
+	};
+	print_cmd_by_category(catdesc);
+	putchar('\n');
+}
+
+void list_all_cmds_help(void)
+{
+	print_cmd_by_category(main_categories);
 }
 
 int is_in_cmdlist(struct cmdnames *c, const char *s)
@@ -285,6 +471,7 @@
 {
 	int i, n, best_similarity = 0;
 	struct cmdnames main_cmds, other_cmds;
+	struct cmdname_help *common_cmds;
 
 	memset(&main_cmds, 0, sizeof(main_cmds));
 	memset(&other_cmds, 0, sizeof(other_cmds));
@@ -299,6 +486,8 @@
 	QSORT(main_cmds.names, main_cmds.cnt, cmdname_compare);
 	uniq(&main_cmds);
 
+	extract_cmds(&common_cmds, common_mask);
+
 	/* This abuses cmdname->len for levenshtein distance */
 	for (i = 0, n = 0; i < main_cmds.cnt; i++) {
 		int cmp = 0; /* avoid compiler stupidity */
@@ -313,10 +502,10 @@
 			die(_(bad_interpreter_advice), cmd, cmd);
 
 		/* Does the candidate appear in common_cmds list? */
-		while (n < ARRAY_SIZE(common_cmds) &&
+		while (common_cmds[n].name &&
 		       (cmp = strcmp(common_cmds[n].name, candidate)) < 0)
 			n++;
-		if ((n < ARRAY_SIZE(common_cmds)) && !cmp) {
+		if (common_cmds[n].name && !cmp) {
 			/* Yes, this is one of the common commands */
 			n++; /* use the entry from common_cmds[] */
 			if (starts_with(candidate, cmd)) {
@@ -329,6 +518,7 @@
 		main_cmds.names[i]->len =
 			levenshtein(cmd, candidate, 0, 2, 1, 3) + 1;
 	}
+	FREE_AND_NULL(common_cmds);
 
 	QSORT(main_cmds.names, main_cmds.cnt, levenshtein_compare);
 
diff --git a/help.h b/help.h
index b21d7c9..3b38292 100644
--- a/help.h
+++ b/help.h
@@ -1,6 +1,8 @@
 #ifndef HELP_H
 #define HELP_H
 
+struct string_list;
+
 struct cmdnames {
 	int alloc;
 	int cnt;
@@ -17,6 +19,14 @@
 }
 
 extern void list_common_cmds_help(void);
+extern void list_all_cmds_help(void);
+extern void list_common_guides_help(void);
+
+extern void list_all_main_cmds(struct string_list *list);
+extern void list_all_other_cmds(struct string_list *list);
+extern void list_cmds_by_category(struct string_list *list,
+				  const char *category);
+extern void list_cmds_by_config(struct string_list *list);
 extern const char *help_unknown_cmd(const char *cmd);
 extern void load_command_list(const char *prefix,
 			      struct cmdnames *main_cmds,
diff --git a/http-backend.c b/http-backend.c
index cc16cd0..adaef16 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -12,6 +12,7 @@
 #include "argv-array.h"
 #include "packfile.h"
 #include "object-store.h"
+#include "protocol.h"
 
 static const char content_type[] = "Content-Type";
 static const char content_length[] = "Content-Length";
@@ -468,8 +469,11 @@
 		hdr_str(hdr, content_type, buf.buf);
 		end_headers(hdr);
 
-		packet_write_fmt(1, "# service=git-%s\n", svc->name);
-		packet_flush(1);
+
+		if (determine_protocol_version_server() != protocol_v2) {
+			packet_write_fmt(1, "# service=git-%s\n", svc->name);
+			packet_flush(1);
+		}
 
 		argv[0] = svc->name;
 		run_service(argv, 0);
diff --git a/http-fetch.c b/http-fetch.c
index 885e471..a32ac11 100644
--- a/http-fetch.c
+++ b/http-fetch.c
@@ -17,21 +17,13 @@
 	char *url = NULL;
 	int arg = 1;
 	int rc = 0;
-	int get_tree = 0;
-	int get_history = 0;
-	int get_all = 0;
 	int get_verbosely = 0;
 	int get_recover = 0;
 
 	while (arg < argc && argv[arg][0] == '-') {
 		if (argv[arg][1] == 't') {
-			get_tree = 1;
 		} else if (argv[arg][1] == 'c') {
-			get_history = 1;
 		} else if (argv[arg][1] == 'a') {
-			get_all = 1;
-			get_tree = 1;
-			get_history = 1;
 		} else if (argv[arg][1] == 'v') {
 			get_verbosely = 1;
 		} else if (argv[arg][1] == 'w') {
@@ -55,10 +47,6 @@
 		commits = 1;
 	}
 
-	if (get_all == 0)
-		warning("http-fetch: use without -a is deprecated.\n"
-			"In a future release, -a will become the default.");
-
 	if (argv[arg])
 		str_end_url_with_slash(argv[arg], &url);
 
@@ -68,9 +56,6 @@
 
 	http_init(NULL, url, 0);
 	walker = get_http_walker(url);
-	walker->get_tree = get_tree;
-	walker->get_history = get_history;
-	walker->get_all = get_all;
 	walker->get_verbosely = get_verbosely;
 	walker->get_recover = get_recover;
 
diff --git a/http-push.c b/http-push.c
index f308ce0..7e38522 100644
--- a/http-push.c
+++ b/http-push.c
@@ -1331,7 +1331,7 @@
 	int count = 0;
 
 	while ((commit = get_revision(revs)) != NULL) {
-		p = process_tree(commit->tree, p);
+		p = process_tree(get_commit_tree(commit), p);
 		commit->object.flags |= LOCAL;
 		if (!(commit->object.flags & UNINTERESTING))
 			count += add_send_request(&commit->object, lock);
@@ -1692,8 +1692,7 @@
 {
 	struct transfer_request *request;
 	struct transfer_request *next_request;
-	int nr_refspec = 0;
-	const char **refspec = NULL;
+	struct refspec rs = REFSPEC_INIT_PUSH;
 	struct remote_lock *ref_lock = NULL;
 	struct remote_lock *info_ref_lock = NULL;
 	struct rev_info revs;
@@ -1756,8 +1755,7 @@
 			}
 			continue;
 		}
-		refspec = argv;
-		nr_refspec = argc - i;
+		refspec_appendn(&rs, argv, argc - i);
 		break;
 	}
 
@@ -1768,7 +1766,7 @@
 	if (!repo->url)
 		usage(http_push_usage);
 
-	if (delete_branch && nr_refspec != 1)
+	if (delete_branch && rs.nr != 1)
 		die("You must specify only one branch name when deleting a remote branch");
 
 	setup_git_directory();
@@ -1814,18 +1812,18 @@
 
 	/* Remove a remote branch if -d or -D was specified */
 	if (delete_branch) {
-		if (delete_remote_branch(refspec[0], force_delete) == -1) {
+		const char *branch = rs.items[i].src;
+		if (delete_remote_branch(branch, force_delete) == -1) {
 			fprintf(stderr, "Unable to delete remote branch %s\n",
-				refspec[0]);
+				branch);
 			if (helper_status)
-				printf("error %s cannot remove\n", refspec[0]);
+				printf("error %s cannot remove\n", branch);
 		}
 		goto cleanup;
 	}
 
 	/* match them up */
-	if (match_push_refs(local_refs, &remote_refs,
-			    nr_refspec, (const char **) refspec, push_all)) {
+	if (match_push_refs(local_refs, &remote_refs, &rs, push_all)) {
 		rc = -1;
 		goto cleanup;
 	}
diff --git a/http.c b/http.c
index 3034d10..b4bfbce 100644
--- a/http.c
+++ b/http.c
@@ -976,21 +976,6 @@
 		*var = val;
 }
 
-static void protocol_http_header(void)
-{
-	if (get_protocol_version_config() > 0) {
-		struct strbuf protocol_header = STRBUF_INIT;
-
-		strbuf_addf(&protocol_header, GIT_PROTOCOL_HEADER ": version=%d",
-			    get_protocol_version_config());
-
-
-		extra_http_headers = curl_slist_append(extra_http_headers,
-						       protocol_header.buf);
-		strbuf_release(&protocol_header);
-	}
-}
-
 void http_init(struct remote *remote, const char *url, int proactive_auth)
 {
 	char *low_speed_limit;
@@ -1021,8 +1006,6 @@
 	if (remote)
 		var_override(&http_proxy_authmethod, remote->http_proxy_authmethod);
 
-	protocol_http_header();
-
 	pragma_header = curl_slist_append(http_copy_default_headers(),
 		"Pragma: no-cache");
 	no_pragma_header = curl_slist_append(http_copy_default_headers(),
@@ -1795,9 +1778,17 @@
 
 	headers = curl_slist_append(headers, buf.buf);
 
+	/* Add additional headers here */
+	if (options && options->extra_headers) {
+		const struct string_list_item *item;
+		for_each_string_list_item(item, options->extra_headers) {
+			headers = curl_slist_append(headers, item->string);
+		}
+	}
+
 	curl_easy_setopt(slot->curl, CURLOPT_URL, url);
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
-	curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "gzip");
+	curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "");
 
 	ret = run_one_slot(slot, &results);
 
@@ -1855,7 +1846,7 @@
 		return 0;
 
 	if (!skip_prefix(asked, base->buf, &tail))
-		die("BUG: update_url_from_redirect: %s is not a superset of %s",
+		BUG("update_url_from_redirect: %s is not a superset of %s",
 		    asked, base->buf);
 
 	new_len = got->len;
@@ -1903,7 +1894,7 @@
 			strbuf_reset(result);
 			break;
 		default:
-			die("BUG: HTTP_KEEP_ERROR is only supported with strbufs");
+			BUG("HTTP_KEEP_ERROR is only supported with strbufs");
 		}
 	}
 
@@ -2047,7 +2038,8 @@
 	int ret = 0, i = 0;
 	char *url, *data;
 	struct strbuf buf = STRBUF_INIT;
-	unsigned char sha1[20];
+	unsigned char hash[GIT_MAX_RAWSZ];
+	const unsigned hexsz = the_hash_algo->hexsz;
 
 	end_url_with_slash(&buf, base_url);
 	strbuf_addstr(&buf, "objects/info/packs");
@@ -2063,13 +2055,13 @@
 		switch (data[i]) {
 		case 'P':
 			i++;
-			if (i + 52 <= buf.len &&
+			if (i + hexsz + 12 <= buf.len &&
 			    starts_with(data + i, " pack-") &&
-			    starts_with(data + i + 46, ".pack\n")) {
-				get_sha1_hex(data + i + 6, sha1);
-				fetch_and_setup_pack_index(packs_head, sha1,
+			    starts_with(data + i + hexsz + 6, ".pack\n")) {
+				get_sha1_hex(data + i + 6, hash);
+				fetch_and_setup_pack_index(packs_head, hash,
 						      base_url);
-				i += 51;
+				i += hexsz + 11;
 				break;
 			}
 		default:
@@ -2091,6 +2083,7 @@
 		preq->packfile = NULL;
 	}
 	preq->slot = NULL;
+	strbuf_release(&preq->tmpfile);
 	free(preq->url);
 	free(preq);
 }
@@ -2113,19 +2106,19 @@
 		lst = &((*lst)->next);
 	*lst = (*lst)->next;
 
-	if (!strip_suffix(preq->tmpfile, ".pack.temp", &len))
-		die("BUG: pack tmpfile does not end in .pack.temp?");
-	tmp_idx = xstrfmt("%.*s.idx.temp", (int)len, preq->tmpfile);
+	if (!strip_suffix(preq->tmpfile.buf, ".pack.temp", &len))
+		BUG("pack tmpfile does not end in .pack.temp?");
+	tmp_idx = xstrfmt("%.*s.idx.temp", (int)len, preq->tmpfile.buf);
 
 	argv_array_push(&ip.args, "index-pack");
 	argv_array_pushl(&ip.args, "-o", tmp_idx, NULL);
-	argv_array_push(&ip.args, preq->tmpfile);
+	argv_array_push(&ip.args, preq->tmpfile.buf);
 	ip.git_cmd = 1;
 	ip.no_stdin = 1;
 	ip.no_stdout = 1;
 
 	if (run_command(&ip)) {
-		unlink(preq->tmpfile);
+		unlink(preq->tmpfile.buf);
 		unlink(tmp_idx);
 		free(tmp_idx);
 		return -1;
@@ -2133,7 +2126,7 @@
 
 	unlink(sha1_pack_index_name(p->sha1));
 
-	if (finalize_object_file(preq->tmpfile, sha1_pack_name(p->sha1))
+	if (finalize_object_file(preq->tmpfile.buf, sha1_pack_name(p->sha1))
 	 || finalize_object_file(tmp_idx, sha1_pack_index_name(p->sha1))) {
 		free(tmp_idx);
 		return -1;
@@ -2152,6 +2145,7 @@
 	struct http_pack_request *preq;
 
 	preq = xcalloc(1, sizeof(*preq));
+	strbuf_init(&preq->tmpfile, 0);
 	preq->target = target;
 
 	end_url_with_slash(&buf, base_url);
@@ -2159,12 +2153,11 @@
 		sha1_to_hex(target->sha1));
 	preq->url = strbuf_detach(&buf, NULL);
 
-	snprintf(preq->tmpfile, sizeof(preq->tmpfile), "%s.temp",
-		sha1_pack_name(target->sha1));
-	preq->packfile = fopen(preq->tmpfile, "a");
+	strbuf_addf(&preq->tmpfile, "%s.temp", sha1_pack_name(target->sha1));
+	preq->packfile = fopen(preq->tmpfile.buf, "a");
 	if (!preq->packfile) {
 		error("Unable to open local file %s for pack",
-		      preq->tmpfile);
+		      preq->tmpfile.buf);
 		goto abort;
 	}
 
@@ -2191,6 +2184,7 @@
 	return preq;
 
 abort:
+	strbuf_release(&preq->tmpfile);
 	free(preq->url);
 	free(preq);
 	return NULL;
@@ -2210,7 +2204,7 @@
 		CURLcode c = curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE,
 						&slot->http_code);
 		if (c != CURLE_OK)
-			die("BUG: curl_easy_getinfo for HTTP code failed: %s",
+			BUG("curl_easy_getinfo for HTTP code failed: %s",
 				curl_easy_strerror(c));
 		if (slot->http_code >= 300)
 			return size;
@@ -2241,7 +2235,7 @@
 {
 	char *hex = sha1_to_hex(sha1);
 	struct strbuf filename = STRBUF_INIT;
-	char prevfile[PATH_MAX];
+	struct strbuf prevfile = STRBUF_INIT;
 	int prevlocal;
 	char prev_buf[PREV_BUF_SIZE];
 	ssize_t prev_read = 0;
@@ -2249,40 +2243,41 @@
 	struct http_object_request *freq;
 
 	freq = xcalloc(1, sizeof(*freq));
+	strbuf_init(&freq->tmpfile, 0);
 	hashcpy(freq->sha1, sha1);
 	freq->localfile = -1;
 
 	sha1_file_name(the_repository, &filename, sha1);
-	snprintf(freq->tmpfile, sizeof(freq->tmpfile),
-		 "%s.temp", filename.buf);
+	strbuf_addf(&freq->tmpfile, "%s.temp", filename.buf);
 
-	snprintf(prevfile, sizeof(prevfile), "%s.prev", filename.buf);
-	unlink_or_warn(prevfile);
-	rename(freq->tmpfile, prevfile);
-	unlink_or_warn(freq->tmpfile);
+	strbuf_addf(&prevfile, "%s.prev", filename.buf);
+	unlink_or_warn(prevfile.buf);
+	rename(freq->tmpfile.buf, prevfile.buf);
+	unlink_or_warn(freq->tmpfile.buf);
 	strbuf_release(&filename);
 
 	if (freq->localfile != -1)
 		error("fd leakage in start: %d", freq->localfile);
-	freq->localfile = open(freq->tmpfile,
+	freq->localfile = open(freq->tmpfile.buf,
 			       O_WRONLY | O_CREAT | O_EXCL, 0666);
 	/*
 	 * This could have failed due to the "lazy directory creation";
 	 * try to mkdir the last path component.
 	 */
 	if (freq->localfile < 0 && errno == ENOENT) {
-		char *dir = strrchr(freq->tmpfile, '/');
+		char *dir = strrchr(freq->tmpfile.buf, '/');
 		if (dir) {
 			*dir = 0;
-			mkdir(freq->tmpfile, 0777);
+			mkdir(freq->tmpfile.buf, 0777);
 			*dir = '/';
 		}
-		freq->localfile = open(freq->tmpfile,
+		freq->localfile = open(freq->tmpfile.buf,
 				       O_WRONLY | O_CREAT | O_EXCL, 0666);
 	}
 
 	if (freq->localfile < 0) {
-		error_errno("Couldn't create temporary file %s", freq->tmpfile);
+		error_errno("Couldn't create temporary file %s",
+			    freq->tmpfile.buf);
 		goto abort;
 	}
 
@@ -2296,7 +2291,7 @@
 	 * If a previous temp file is present, process what was already
 	 * fetched.
 	 */
-	prevlocal = open(prevfile, O_RDONLY);
+	prevlocal = open(prevfile.buf, O_RDONLY);
 	if (prevlocal != -1) {
 		do {
 			prev_read = xread(prevlocal, prev_buf, PREV_BUF_SIZE);
@@ -2313,7 +2308,8 @@
 		} while (prev_read > 0);
 		close(prevlocal);
 	}
-	unlink_or_warn(prevfile);
+	unlink_or_warn(prevfile.buf);
+	strbuf_release(&prevfile);
 
 	/*
 	 * Reset inflate/SHA1 if there was an error reading the previous temp
@@ -2328,7 +2324,7 @@
 			lseek(freq->localfile, 0, SEEK_SET);
 			if (ftruncate(freq->localfile, 0) < 0) {
 				error_errno("Couldn't truncate temporary file %s",
-					    freq->tmpfile);
+					    freq->tmpfile.buf);
 				goto abort;
 			}
 		}
@@ -2358,6 +2354,7 @@
 	return freq;
 
 abort:
+	strbuf_release(&prevfile);
 	free(freq->url);
 	free(freq);
 	return NULL;
@@ -2385,24 +2382,24 @@
 	if (freq->http_code == 416) {
 		warning("requested range invalid; we may already have all the data.");
 	} else if (freq->curl_result != CURLE_OK) {
-		if (stat(freq->tmpfile, &st) == 0)
+		if (stat(freq->tmpfile.buf, &st) == 0)
 			if (st.st_size == 0)
-				unlink_or_warn(freq->tmpfile);
+				unlink_or_warn(freq->tmpfile.buf);
 		return -1;
 	}
 
 	git_inflate_end(&freq->stream);
 	git_SHA1_Final(freq->real_sha1, &freq->c);
 	if (freq->zret != Z_STREAM_END) {
-		unlink_or_warn(freq->tmpfile);
+		unlink_or_warn(freq->tmpfile.buf);
 		return -1;
 	}
 	if (hashcmp(freq->sha1, freq->real_sha1)) {
-		unlink_or_warn(freq->tmpfile);
+		unlink_or_warn(freq->tmpfile.buf);
 		return -1;
 	}
 	sha1_file_name(the_repository, &filename, freq->sha1);
-	freq->rename = finalize_object_file(freq->tmpfile, filename.buf);
+	freq->rename = finalize_object_file(freq->tmpfile.buf, filename.buf);
 	strbuf_release(&filename);
 
 	return freq->rename;
@@ -2410,7 +2407,7 @@
 
 void abort_http_object_request(struct http_object_request *freq)
 {
-	unlink_or_warn(freq->tmpfile);
+	unlink_or_warn(freq->tmpfile.buf);
 
 	release_http_object_request(freq);
 }
@@ -2430,4 +2427,5 @@
 		release_active_slot(freq->slot);
 		freq->slot = NULL;
 	}
+	strbuf_release(&freq->tmpfile);
 }
diff --git a/http.h b/http.h
index f7bd3b2..d305ca1 100644
--- a/http.h
+++ b/http.h
@@ -172,6 +172,13 @@
 	 * for details.
 	 */
 	struct strbuf *base_url;
+
+	/*
+	 * If not NULL, contains additional HTTP headers to be sent with the
+	 * request. The strings in the list must not be freed until after the
+	 * request has completed.
+	 */
+	struct string_list *extra_headers;
 };
 
 /* Return values for http_get_*() */
@@ -200,7 +207,7 @@
 	struct packed_git *target;
 	struct packed_git **lst;
 	FILE *packfile;
-	char tmpfile[PATH_MAX];
+	struct strbuf tmpfile;
 	struct active_request_slot *slot;
 };
 
@@ -212,7 +219,7 @@
 /* Helpers for fetching object */
 struct http_object_request {
 	char *url;
-	char tmpfile[PATH_MAX];
+	struct strbuf tmpfile;
 	int localfile;
 	CURLcode curl_result;
 	char errorstr[CURL_ERROR_SIZE];
diff --git a/imap-send.c b/imap-send.c
index 3573cbf..b4eb886 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -511,7 +511,7 @@
 
 	va_start(va, fmt);
 	if (blen <= 0 || (unsigned)(ret = vsnprintf(buf, blen, fmt, va)) >= (unsigned)blen)
-		die("BUG: buffer too small. Please report a bug.");
+		BUG("buffer too small. Please report a bug.");
 	va_end(va);
 	return ret;
 }
diff --git a/line-log.c b/line-log.c
index ecdce08..fa9cfd5 100644
--- a/line-log.c
+++ b/line-log.c
@@ -816,8 +816,8 @@
 	assert(commit);
 
 	DIFF_QUEUE_CLEAR(&diff_queued_diff);
-	diff_tree_oid(parent ? &parent->tree->object.oid : NULL,
-		      &commit->tree->object.oid, "", opt);
+	diff_tree_oid(parent ? get_commit_tree_oid(parent) : NULL,
+		      get_commit_tree_oid(commit), "", opt);
 	if (opt->detect_rename) {
 		filter_diffs_for_paths(range, 1);
 		if (diff_might_be_rename())
diff --git a/list-objects-filter.c b/list-objects-filter.c
index 2477175..5b14d27 100644
--- a/list-objects-filter.c
+++ b/list-objects-filter.c
@@ -117,7 +117,7 @@
 		assert(obj->type == OBJ_BLOB);
 		assert((obj->flags & SEEN) == 0);
 
-		t = oid_object_info(&obj->oid, &object_length);
+		t = oid_object_info(the_repository, &obj->oid, &object_length);
 		if (t != OBJ_BLOB) { /* probably OBJ_NONE */
 			/*
 			 * We DO NOT have the blob locally, so we cannot
diff --git a/list-objects.c b/list-objects.c
index 168bef6..3eec510 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -195,7 +195,7 @@
 		struct commit *parent = parents->item;
 		if (!(parent->object.flags & UNINTERESTING))
 			continue;
-		mark_tree_uninteresting(parent->tree);
+		mark_tree_uninteresting(get_commit_tree(parent));
 		if (revs->edge_hint && !(parent->object.flags & SHOWN)) {
 			parent->object.flags |= SHOWN;
 			show_edge(parent);
@@ -212,7 +212,7 @@
 		struct commit *commit = list->item;
 
 		if (commit->object.flags & UNINTERESTING) {
-			mark_tree_uninteresting(commit->tree);
+			mark_tree_uninteresting(get_commit_tree(commit));
 			if (revs->edge_hint_aggressive && !(commit->object.flags & SHOWN)) {
 				commit->object.flags |= SHOWN;
 				show_edge(commit);
@@ -227,7 +227,7 @@
 			struct commit *commit = (struct commit *)obj;
 			if (obj->type != OBJ_COMMIT || !(obj->flags & UNINTERESTING))
 				continue;
-			mark_tree_uninteresting(commit->tree);
+			mark_tree_uninteresting(get_commit_tree(commit));
 			if (!(obj->flags & SHOWN)) {
 				obj->flags |= SHOWN;
 				show_edge(commit);
@@ -300,8 +300,8 @@
 		 * an uninteresting boundary commit may not have its tree
 		 * parsed yet, but we are not going to show them anyway
 		 */
-		if (commit->tree)
-			add_pending_tree(revs, commit->tree);
+		if (get_commit_tree(commit))
+			add_pending_tree(revs, get_commit_tree(commit));
 		show_commit(commit, show_data);
 
 		if (revs->tree_blobs_in_commit_order)
diff --git a/lockfile.c b/lockfile.c
index efcb7d7..8e8ab4f 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -193,7 +193,7 @@
 	strbuf_addstr(&ret, get_tempfile_path(lk->tempfile));
 	if (ret.len <= LOCK_SUFFIX_LEN ||
 	    strcmp(ret.buf + ret.len - LOCK_SUFFIX_LEN, LOCK_SUFFIX))
-		die("BUG: get_locked_file_path() called for malformed lock object");
+		BUG("get_locked_file_path() called for malformed lock object");
 	/* remove ".lock": */
 	strbuf_setlen(&ret, ret.len - LOCK_SUFFIX_LEN);
 	return strbuf_detach(&ret, NULL);
diff --git a/log-tree.c b/log-tree.c
index d1c0bed..4aef853 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -362,7 +362,8 @@
 
 void log_write_email_headers(struct rev_info *opt, struct commit *commit,
 			     const char **extra_headers_p,
-			     int *need_8bit_cte_p)
+			     int *need_8bit_cte_p,
+			     int maybe_multipart)
 {
 	const char *extra_headers = opt->extra_headers;
 	const char *name = oid_to_hex(opt->zero_commit ?
@@ -385,12 +386,16 @@
 			       opt->ref_message_ids->items[i].string);
 		graph_show_oneline(opt->graph);
 	}
-	if (opt->mime_boundary) {
-		static char subject_buffer[1024];
-		static char buffer[1024];
+	if (opt->mime_boundary && maybe_multipart) {
+		static struct strbuf subject_buffer = STRBUF_INIT;
+		static struct strbuf buffer = STRBUF_INIT;
 		struct strbuf filename =  STRBUF_INIT;
 		*need_8bit_cte_p = -1; /* NEVER */
-		snprintf(subject_buffer, sizeof(subject_buffer) - 1,
+
+		strbuf_reset(&subject_buffer);
+		strbuf_reset(&buffer);
+
+		strbuf_addf(&subject_buffer,
 			 "%s"
 			 "MIME-Version: 1.0\n"
 			 "Content-Type: multipart/mixed;"
@@ -405,13 +410,13 @@
 			 extra_headers ? extra_headers : "",
 			 mime_boundary_leader, opt->mime_boundary,
 			 mime_boundary_leader, opt->mime_boundary);
-		extra_headers = subject_buffer;
+		extra_headers = subject_buffer.buf;
 
 		if (opt->numbered_files)
 			strbuf_addf(&filename, "%d", opt->nr);
 		else
 			fmt_output_commit(&filename, commit, opt);
-		snprintf(buffer, sizeof(buffer) - 1,
+		strbuf_addf(&buffer,
 			 "\n--%s%s\n"
 			 "Content-Type: text/x-patch;"
 			 " name=\"%s\"\n"
@@ -422,7 +427,7 @@
 			 filename.buf,
 			 opt->no_inline ? "attachment" : "inline",
 			 filename.buf);
-		opt->diffopt.stat_sep = buffer;
+		opt->diffopt.stat_sep = buffer.buf;
 		strbuf_release(&filename);
 	}
 	*extra_headers_p = extra_headers;
@@ -488,9 +493,9 @@
 		&& !commit->parents->next->next);
 }
 
-static void show_one_mergetag(struct commit *commit,
-			      struct commit_extra_header *extra,
-			      void *data)
+static int show_one_mergetag(struct commit *commit,
+			     struct commit_extra_header *extra,
+			     void *data)
 {
 	struct rev_info *opt = (struct rev_info *)data;
 	struct object_id oid;
@@ -502,7 +507,7 @@
 	hash_object_file(extra->value, extra->len, type_name(OBJ_TAG), &oid);
 	tag = lookup_tag(&oid);
 	if (!tag)
-		return; /* error message already given */
+		return -1; /* error message already given */
 
 	strbuf_init(&verify_message, 256);
 	if (parse_tag_buffer(tag, extra->value, extra->len))
@@ -536,11 +541,12 @@
 
 	show_sig_lines(opt, status, verify_message.buf);
 	strbuf_release(&verify_message);
+	return 0;
 }
 
-static void show_mergetag(struct rev_info *opt, struct commit *commit)
+static int show_mergetag(struct rev_info *opt, struct commit *commit)
 {
-	for_each_mergetag(show_one_mergetag, commit, opt);
+	return for_each_mergetag(show_one_mergetag, commit, opt);
 }
 
 void show_log(struct rev_info *opt)
@@ -610,7 +616,7 @@
 
 	if (cmit_fmt_is_mail(opt->commit_format)) {
 		log_write_email_headers(opt, commit, &extra_headers,
-					&ctx.need_8bit_cte);
+					&ctx.need_8bit_cte, 1);
 		ctx.rev = opt;
 		ctx.print_email_subject = 1;
 	} else if (opt->commit_format != CMIT_FMT_USERFORMAT) {
@@ -806,7 +812,7 @@
 		return 0;
 
 	parse_commit_or_die(commit);
-	oid = &commit->tree->object.oid;
+	oid = get_commit_tree_oid(commit);
 
 	/* Root commit? */
 	parents = get_saved_parents(opt, commit);
@@ -831,7 +837,7 @@
 			 * we merged _in_.
 			 */
 			parse_commit_or_die(parents->item);
-			diff_tree_oid(&parents->item->tree->object.oid,
+			diff_tree_oid(get_commit_tree_oid(parents->item),
 				      oid, "", &opt->diffopt);
 			log_tree_diff_flush(opt);
 			return !opt->loginfo;
@@ -846,7 +852,7 @@
 		struct commit *parent = parents->item;
 
 		parse_commit_or_die(parent);
-		diff_tree_oid(&parent->tree->object.oid,
+		diff_tree_oid(get_commit_tree_oid(parent),
 			      oid, "", &opt->diffopt);
 		log_tree_diff_flush(opt);
 
diff --git a/log-tree.h b/log-tree.h
index deba035..e668628 100644
--- a/log-tree.h
+++ b/log-tree.h
@@ -27,7 +27,8 @@
 void show_decorations(struct rev_info *opt, struct commit *commit);
 void log_write_email_headers(struct rev_info *opt, struct commit *commit,
 			     const char **extra_headers_p,
-			     int *need_8bit_cte_p);
+			     int *need_8bit_cte_p,
+			     int maybe_multipart);
 void load_ref_decorations(struct decoration_filter *filter, int flags);
 
 #define FORMAT_PATCH_NAME_MAX 64
diff --git a/ls-refs.c b/ls-refs.c
new file mode 100644
index 0000000..a06f12e
--- /dev/null
+++ b/ls-refs.c
@@ -0,0 +1,96 @@
+#include "cache.h"
+#include "repository.h"
+#include "refs.h"
+#include "remote.h"
+#include "argv-array.h"
+#include "ls-refs.h"
+#include "pkt-line.h"
+
+/*
+ * Check if one of the prefixes is a prefix of the ref.
+ * If no prefixes were provided, all refs match.
+ */
+static int ref_match(const struct argv_array *prefixes, const char *refname)
+{
+	int i;
+
+	if (!prefixes->argc)
+		return 1; /* no restriction */
+
+	for (i = 0; i < prefixes->argc; i++) {
+		const char *prefix = prefixes->argv[i];
+
+		if (starts_with(refname, prefix))
+			return 1;
+	}
+
+	return 0;
+}
+
+struct ls_refs_data {
+	unsigned peel;
+	unsigned symrefs;
+	struct argv_array prefixes;
+};
+
+static int send_ref(const char *refname, const struct object_id *oid,
+		    int flag, void *cb_data)
+{
+	struct ls_refs_data *data = cb_data;
+	const char *refname_nons = strip_namespace(refname);
+	struct strbuf refline = STRBUF_INIT;
+
+	if (!ref_match(&data->prefixes, refname))
+		return 0;
+
+	strbuf_addf(&refline, "%s %s", oid_to_hex(oid), refname_nons);
+	if (data->symrefs && flag & REF_ISSYMREF) {
+		struct object_id unused;
+		const char *symref_target = resolve_ref_unsafe(refname, 0,
+							       &unused,
+							       &flag);
+
+		if (!symref_target)
+			die("'%s' is a symref but it is not?", refname);
+
+		strbuf_addf(&refline, " symref-target:%s", symref_target);
+	}
+
+	if (data->peel) {
+		struct object_id peeled;
+		if (!peel_ref(refname, &peeled))
+			strbuf_addf(&refline, " peeled:%s", oid_to_hex(&peeled));
+	}
+
+	strbuf_addch(&refline, '\n');
+	packet_write(1, refline.buf, refline.len);
+
+	strbuf_release(&refline);
+	return 0;
+}
+
+int ls_refs(struct repository *r, struct argv_array *keys,
+	    struct packet_reader *request)
+{
+	struct ls_refs_data data;
+
+	memset(&data, 0, sizeof(data));
+
+	while (packet_reader_read(request) != PACKET_READ_FLUSH) {
+		const char *arg = request->line;
+		const char *out;
+
+		if (!strcmp("peel", arg))
+			data.peel = 1;
+		else if (!strcmp("symrefs", arg))
+			data.symrefs = 1;
+		else if (skip_prefix(arg, "ref-prefix ", &out))
+			argv_array_push(&data.prefixes, out);
+	}
+
+	head_ref_namespaced(send_ref, &data);
+	for_each_namespaced_ref(send_ref, &data);
+	packet_flush(1);
+	argv_array_clear(&data.prefixes);
+	return 0;
+}
diff --git a/ls-refs.h b/ls-refs.h
new file mode 100644
index 0000000..b62877e
--- /dev/null
+++ b/ls-refs.h
@@ -0,0 +1,10 @@
+#ifndef LS_REFS_H
+#define LS_REFS_H
+
+struct repository;
+struct argv_array;
+struct packet_reader;
+extern int ls_refs(struct repository *r, struct argv_array *keys,
+		   struct packet_reader *request);
+
+#endif /* LS_REFS_H */
diff --git a/mailinfo.c b/mailinfo.c
index d04142c..3281a37 100644
--- a/mailinfo.c
+++ b/mailinfo.c
@@ -716,7 +716,7 @@
 	if (!mi->inbody_header_accum.len)
 		return;
 	if (!check_header(mi, &mi->inbody_header_accum, mi->s_hdr_data, 0))
-		die("BUG: inbody_header_accum, if not empty, must always contain a valid in-body header");
+		BUG("inbody_header_accum, if not empty, must always contain a valid in-body header");
 	strbuf_reset(&mi->inbody_header_accum);
 }
 
diff --git a/merge-recursive.c b/merge-recursive.c
index 0c0d486..ac27abb 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -23,6 +23,7 @@
 #include "merge-recursive.h"
 #include "dir.h"
 #include "submodule.h"
+#include "revision.h"
 
 struct path_hashmap_entry {
 	struct hashmap_entry e;
@@ -49,6 +50,67 @@
 	return ignore_case ? strihash(path) : strhash(path);
 }
 
+static struct dir_rename_entry *dir_rename_find_entry(struct hashmap *hashmap,
+						      char *dir)
+{
+	struct dir_rename_entry key;
+
+	if (dir == NULL)
+		return NULL;
+	hashmap_entry_init(&key, strhash(dir));
+	key.dir = dir;
+	return hashmap_get(hashmap, &key, NULL);
+}
+
+static int dir_rename_cmp(const void *unused_cmp_data,
+			  const void *entry,
+			  const void *entry_or_key,
+			  const void *unused_keydata)
+{
+	const struct dir_rename_entry *e1 = entry;
+	const struct dir_rename_entry *e2 = entry_or_key;
+
+	return strcmp(e1->dir, e2->dir);
+}
+
+static void dir_rename_init(struct hashmap *map)
+{
+	hashmap_init(map, dir_rename_cmp, NULL, 0);
+}
+
+static void dir_rename_entry_init(struct dir_rename_entry *entry,
+				  char *directory)
+{
+	hashmap_entry_init(entry, strhash(directory));
+	entry->dir = directory;
+	entry->non_unique_new_dir = 0;
+	strbuf_init(&entry->new_dir, 0);
+	string_list_init(&entry->possible_new_dirs, 0);
+}
+
+static struct collision_entry *collision_find_entry(struct hashmap *hashmap,
+						    char *target_file)
+{
+	struct collision_entry key;
+
+	hashmap_entry_init(&key, strhash(target_file));
+	key.target_file = target_file;
+	return hashmap_get(hashmap, &key, NULL);
+}
+
+static int collision_cmp(void *unused_cmp_data,
+			 const struct collision_entry *e1,
+			 const struct collision_entry *e2,
+			 const void *unused_keydata)
+{
+	return strcmp(e1->target_file, e2->target_file);
+}
+
+static void collision_init(struct hashmap *map)
+{
+	hashmap_init(map, (hashmap_cmp_fn) collision_cmp, NULL, 0);
+}
+
 static void flush_output(struct merge_options *o)
 {
 	if (o->buffer_output < 2 && o->obuf.len) {
@@ -101,7 +163,7 @@
 	struct commit *commit = alloc_commit_node();
 
 	set_merge_remote_desc(commit, comment, (struct object *)commit);
-	commit->tree = tree;
+	commit->maybe_tree = tree;
 	commit->object.parsed = 1;
 	return commit;
 }
@@ -119,6 +181,7 @@
 
 enum rename_type {
 	RENAME_NORMAL = 0,
+	RENAME_DIR,
 	RENAME_DELETE,
 	RENAME_ONE_FILE_TO_ONE,
 	RENAME_ONE_FILE_TO_TWO,
@@ -254,7 +317,7 @@
 
 	ce = make_cache_entry(mode, oid ? oid->hash : null_sha1, path, stage, 0);
 	if (!ce)
-		return err(o, _("addinfo_cache failed for path '%s'"), path);
+		return err(o, _("add_cacheinfo failed for path '%s'; merge aborting."), path);
 
 	ret = add_cache_entry(ce, options);
 	if (refresh) {
@@ -262,7 +325,7 @@
 
 		nce = refresh_cache_entry(ce, CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
 		if (!nce)
-			return err(o, _("addinfo_cache failed for path '%s'"), path);
+			return err(o, _("add_cacheinfo failed to refresh for path '%s'; merge aborting."), path);
 		if (nce != ce)
 			ret = add_cache_entry(nce, options);
 	}
@@ -275,36 +338,54 @@
 	init_tree_desc(desc, tree->buffer, tree->size);
 }
 
-static int git_merge_trees(int index_only,
-			   struct tree *common,
-			   struct tree *head,
-			   struct tree *merge)
+static int unpack_trees_start(struct merge_options *o,
+			      struct tree *common,
+			      struct tree *head,
+			      struct tree *merge)
 {
 	int rc;
 	struct tree_desc t[3];
-	struct unpack_trees_options opts;
+	struct index_state tmp_index = { NULL };
 
-	memset(&opts, 0, sizeof(opts));
-	if (index_only)
-		opts.index_only = 1;
+	memset(&o->unpack_opts, 0, sizeof(o->unpack_opts));
+	if (o->call_depth)
+		o->unpack_opts.index_only = 1;
 	else
-		opts.update = 1;
-	opts.merge = 1;
-	opts.head_idx = 2;
-	opts.fn = threeway_merge;
-	opts.src_index = &the_index;
-	opts.dst_index = &the_index;
-	setup_unpack_trees_porcelain(&opts, "merge");
+		o->unpack_opts.update = 1;
+	o->unpack_opts.merge = 1;
+	o->unpack_opts.head_idx = 2;
+	o->unpack_opts.fn = threeway_merge;
+	o->unpack_opts.src_index = &the_index;
+	o->unpack_opts.dst_index = &tmp_index;
+	o->unpack_opts.aggressive = !merge_detect_rename(o);
+	setup_unpack_trees_porcelain(&o->unpack_opts, "merge");
 
 	init_tree_desc_from_tree(t+0, common);
 	init_tree_desc_from_tree(t+1, head);
 	init_tree_desc_from_tree(t+2, merge);
 
-	rc = unpack_trees(3, t, &opts);
+	rc = unpack_trees(3, t, &o->unpack_opts);
 	cache_tree_free(&active_cache_tree);
+
+	/*
+	 * Update the_index to match the new results, AFTER saving a copy
+	 * in o->orig_index.  Update src_index to point to the saved copy.
+	 * (verify_uptodate() checks src_index, and the original index is
+	 * the one that had the necessary modification timestamps.)
+	 */
+	o->orig_index = the_index;
+	the_index = tmp_index;
+	o->unpack_opts.src_index = &o->orig_index;
+
 	return rc;
 }
 
+static void unpack_trees_finish(struct merge_options *o)
+{
+	discard_index(&o->orig_index);
+	clear_unpack_trees_porcelain(&o->unpack_opts);
+}
+
 struct tree *write_tree_from_memory(struct merge_options *o)
 {
 	struct tree *result = NULL;
@@ -318,7 +399,7 @@
 				fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
 					(int)ce_namelen(ce), ce->name);
 		}
-		die("BUG: unmerged index entries in merge-recursive.c");
+		BUG("unmerged index entries in merge-recursive.c");
 	}
 
 	if (!active_cache_tree)
@@ -360,6 +441,21 @@
 	read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o);
 }
 
+static int get_tree_entry_if_blob(const struct object_id *tree,
+				  const char *path,
+				  struct object_id *hashy,
+				  unsigned int *mode_o)
+{
+	int ret;
+
+	ret = get_tree_entry(tree, path, hashy, mode_o);
+	if (S_ISDIR(*mode_o)) {
+		oidcpy(hashy, &null_oid);
+		*mode_o = 0;
+	}
+	return ret;
+}
+
 /*
  * Returns an index_entry instance which doesn't have to correspond to
  * a real cache entry in Git's index.
@@ -370,12 +466,12 @@
 {
 	struct string_list_item *item;
 	struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
-	get_tree_entry(&o->object.oid, path,
-			&e->stages[1].oid, &e->stages[1].mode);
-	get_tree_entry(&a->object.oid, path,
-			&e->stages[2].oid, &e->stages[2].mode);
-	get_tree_entry(&b->object.oid, path,
-			&e->stages[3].oid, &e->stages[3].mode);
+	get_tree_entry_if_blob(&o->object.oid, path,
+			       &e->stages[1].oid, &e->stages[1].mode);
+	get_tree_entry_if_blob(&a->object.oid, path,
+			       &e->stages[2].oid, &e->stages[2].mode);
+	get_tree_entry_if_blob(&b->object.oid, path,
+			       &e->stages[3].oid, &e->stages[3].mode);
 	item = string_list_insert(entries, path);
 	item->util = e;
 	return e;
@@ -534,78 +630,10 @@
 	 */
 	struct stage_data *src_entry;
 	struct stage_data *dst_entry;
+	unsigned add_turned_into_rename:1;
 	unsigned processed:1;
 };
 
-/*
- * Get information of all renames which occurred between 'o_tree' and
- * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
- * 'b_tree') to be able to associate the correct cache entries with
- * the rename information. 'tree' is always equal to either a_tree or b_tree.
- */
-static struct string_list *get_renames(struct merge_options *o,
-				       struct tree *tree,
-				       struct tree *o_tree,
-				       struct tree *a_tree,
-				       struct tree *b_tree,
-				       struct string_list *entries)
-{
-	int i;
-	struct string_list *renames;
-	struct diff_options opts;
-
-	renames = xcalloc(1, sizeof(struct string_list));
-	if (!o->detect_rename)
-		return renames;
-
-	diff_setup(&opts);
-	opts.flags.recursive = 1;
-	opts.flags.rename_empty = 0;
-	opts.detect_rename = DIFF_DETECT_RENAME;
-	opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
-			    o->diff_rename_limit >= 0 ? o->diff_rename_limit :
-			    1000;
-	opts.rename_score = o->rename_score;
-	opts.show_rename_progress = o->show_rename_progress;
-	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
-	diff_setup_done(&opts);
-	diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
-	diffcore_std(&opts);
-	if (opts.needed_rename_limit > o->needed_rename_limit)
-		o->needed_rename_limit = opts.needed_rename_limit;
-	for (i = 0; i < diff_queued_diff.nr; ++i) {
-		struct string_list_item *item;
-		struct rename *re;
-		struct diff_filepair *pair = diff_queued_diff.queue[i];
-		if (pair->status != 'R') {
-			diff_free_filepair(pair);
-			continue;
-		}
-		re = xmalloc(sizeof(*re));
-		re->processed = 0;
-		re->pair = pair;
-		item = string_list_lookup(entries, re->pair->one->path);
-		if (!item)
-			re->src_entry = insert_stage_data(re->pair->one->path,
-					o_tree, a_tree, b_tree, entries);
-		else
-			re->src_entry = item->util;
-
-		item = string_list_lookup(entries, re->pair->two->path);
-		if (!item)
-			re->dst_entry = insert_stage_data(re->pair->two->path,
-					o_tree, a_tree, b_tree, entries);
-		else
-			re->dst_entry = item->util;
-		item = string_list_insert(renames, pair->one->path);
-		item->util = re;
-	}
-	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
-	diff_queued_diff.nr = 0;
-	diff_flush(&opts);
-	return renames;
-}
-
 static int update_stages(struct merge_options *opt, const char *path,
 			 const struct diff_filespec *o,
 			 const struct diff_filespec *a,
@@ -637,6 +665,27 @@
 	return 0;
 }
 
+static int update_stages_for_stage_data(struct merge_options *opt,
+					const char *path,
+					const struct stage_data *stage_data)
+{
+	struct diff_filespec o, a, b;
+
+	o.mode = stage_data->stages[1].mode;
+	oidcpy(&o.oid, &stage_data->stages[1].oid);
+
+	a.mode = stage_data->stages[2].mode;
+	oidcpy(&a.oid, &stage_data->stages[2].oid);
+
+	b.mode = stage_data->stages[3].mode;
+	oidcpy(&b.oid, &stage_data->stages[3].oid);
+
+	return update_stages(opt, path,
+			     is_null_oid(&o.oid) ? NULL : &o,
+			     is_null_oid(&a.oid) ? NULL : &a,
+			     is_null_oid(&b.oid) ? NULL : &b);
+}
+
 static void update_entry(struct stage_data *entry,
 			 struct diff_filespec *o,
 			 struct diff_filespec *a,
@@ -738,31 +787,92 @@
 		!(empty_ok && is_empty_dir(path));
 }
 
-static int was_tracked(const char *path)
+/*
+ * Returns whether path was tracked in the index before the merge started,
+ * and its oid and mode match the specified values
+ */
+static int was_tracked_and_matches(struct merge_options *o, const char *path,
+				   const struct object_id *oid, unsigned mode)
 {
-	int pos = cache_name_pos(path, strlen(path));
+	int pos = index_name_pos(&o->orig_index, path, strlen(path));
+	struct cache_entry *ce;
+
+	if (0 > pos)
+		/* we were not tracking this path before the merge */
+		return 0;
+
+	/* See if the file we were tracking before matches */
+	ce = o->orig_index.cache[pos];
+	return (oid_eq(&ce->oid, oid) && ce->ce_mode == mode);
+}
+
+/*
+ * Returns whether path was tracked in the index before the merge started
+ */
+static int was_tracked(struct merge_options *o, const char *path)
+{
+	int pos = index_name_pos(&o->orig_index, path, strlen(path));
 
 	if (0 <= pos)
-		/* we have been tracking this path */
+		/* we were tracking this path before the merge */
 		return 1;
 
-	/*
-	 * Look for an unmerged entry for the path,
-	 * specifically stage #2, which would indicate
-	 * that "our" side before the merge started
-	 * had the path tracked (and resulted in a conflict).
-	 */
-	for (pos = -1 - pos;
-	     pos < active_nr && !strcmp(path, active_cache[pos]->name);
-	     pos++)
-		if (ce_stage(active_cache[pos]) == 2)
-			return 1;
 	return 0;
 }
 
 static int would_lose_untracked(const char *path)
 {
-	return !was_tracked(path) && file_exists(path);
+	/*
+	 * This may look like it can be simplified to:
+	 *   return !was_tracked(o, path) && file_exists(path)
+	 * but it can't.  This function needs to know whether path was in
+	 * the working tree due to EITHER having been tracked in the index
+	 * before the merge OR having been put into the working copy and
+	 * index by unpack_trees().  Due to that either-or requirement, we
+	 * check the current index instead of the original one.
+	 *
+	 * Note that we do not need to worry about merge-recursive itself
+	 * updating the index after unpack_trees() and before calling this
+	 * function, because we strictly require all code paths in
+	 * merge-recursive to update the working tree first and the index
+	 * second.  Doing otherwise would break
+	 * update_file()/would_lose_untracked(); see every comment in this
+	 * file which mentions "update_stages".
+	 */
+	int pos = cache_name_pos(path, strlen(path));
+
+	if (pos < 0)
+		pos = -1 - pos;
+	while (pos < active_nr &&
+	       !strcmp(path, active_cache[pos]->name)) {
+		/*
+		 * If stage #0, it is definitely tracked.
+		 * If it has stage #2 then it was tracked
+		 * before this merge started.  All other
+		 * cases the path was not tracked.
+		 */
+		switch (ce_stage(active_cache[pos])) {
+		case 0:
+		case 2:
+			return 0;
+		}
+		pos++;
+	}
+	return file_exists(path);
+}
+
+static int was_dirty(struct merge_options *o, const char *path)
+{
+	struct cache_entry *ce;
+	int dirty = 1;
+
+	if (o->call_depth || !was_tracked(o, path))
+		return !dirty;
+
+	ce = index_file_exists(o->unpack_opts.src_index,
+			       path, strlen(path), ignore_case);
+	dirty = verify_uptodate(ce, &o->unpack_opts) != 0;
+	return dirty;
 }
 
 static int make_room_for_path(struct merge_options *o, const char *path)
@@ -893,7 +1003,9 @@
 	}
  update_index:
 	if (!ret && update_cache)
-		add_cacheinfo(o, mode, oid, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
+		if (add_cacheinfo(o, mode, oid, path, 0, update_wd,
+				  ADD_CACHE_OK_TO_ADD))
+			return -1;
 	return ret;
 }
 
@@ -977,13 +1089,193 @@
 	return merge_status;
 }
 
+static int find_first_merges(struct object_array *result, const char *path,
+		struct commit *a, struct commit *b)
+{
+	int i, j;
+	struct object_array merges = OBJECT_ARRAY_INIT;
+	struct commit *commit;
+	int contains_another;
+
+	char merged_revision[42];
+	const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
+				   "--all", merged_revision, NULL };
+	struct rev_info revs;
+	struct setup_revision_opt rev_opts;
+
+	memset(result, 0, sizeof(struct object_array));
+	memset(&rev_opts, 0, sizeof(rev_opts));
+
+	/* get all revisions that merge commit a */
+	xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
+			oid_to_hex(&a->object.oid));
+	init_revisions(&revs, NULL);
+	rev_opts.submodule = path;
+	/* FIXME: can't handle linked worktrees in submodules yet */
+	revs.single_worktree = path != NULL;
+	setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);
+
+	/* save all revisions from the above list that contain b */
+	if (prepare_revision_walk(&revs))
+		die("revision walk setup failed");
+	while ((commit = get_revision(&revs)) != NULL) {
+		struct object *o = &(commit->object);
+		if (in_merge_bases(b, commit))
+			add_object_array(o, NULL, &merges);
+	}
+	reset_revision_walk();
+
+	/* Now we've got all merges that contain a and b. Prune all
+	 * merges that contain another found merge and save them in
+	 * result.
+	 */
+	for (i = 0; i < merges.nr; i++) {
+		struct commit *m1 = (struct commit *) merges.objects[i].item;
+
+		contains_another = 0;
+		for (j = 0; j < merges.nr; j++) {
+			struct commit *m2 = (struct commit *) merges.objects[j].item;
+			if (i != j && in_merge_bases(m2, m1)) {
+				contains_another = 1;
+				break;
+			}
+		}
+
+		if (!contains_another)
+			add_object_array(merges.objects[i].item, NULL, result);
+	}
+
+	object_array_clear(&merges);
+	return result->nr;
+}
+
+static void print_commit(struct commit *commit)
+{
+	struct strbuf sb = STRBUF_INIT;
+	struct pretty_print_context ctx = {0};
+	ctx.date_mode.type = DATE_NORMAL;
+	format_commit_message(commit, " %h: %m %s", &sb, &ctx);
+	fprintf(stderr, "%s\n", sb.buf);
+	strbuf_release(&sb);
+}
+
+static int merge_submodule(struct merge_options *o,
+			   struct object_id *result, const char *path,
+			   const struct object_id *base, const struct object_id *a,
+			   const struct object_id *b)
+{
+	struct commit *commit_base, *commit_a, *commit_b;
+	int parent_count;
+	struct object_array merges;
+
+	int i;
+	int search = !o->call_depth;
+
+	/* store a in result in case we fail */
+	oidcpy(result, a);
+
+	/* we can not handle deletion conflicts */
+	if (is_null_oid(base))
+		return 0;
+	if (is_null_oid(a))
+		return 0;
+	if (is_null_oid(b))
+		return 0;
+
+	if (add_submodule_odb(path)) {
+		output(o, 1, _("Failed to merge submodule %s (not checked out)"), path);
+		return 0;
+	}
+
+	if (!(commit_base = lookup_commit_reference(base)) ||
+	    !(commit_a = lookup_commit_reference(a)) ||
+	    !(commit_b = lookup_commit_reference(b))) {
+		output(o, 1, _("Failed to merge submodule %s (commits not present)"), path);
+		return 0;
+	}
+
+	/* check whether both changes are forward */
+	if (!in_merge_bases(commit_base, commit_a) ||
+	    !in_merge_bases(commit_base, commit_b)) {
+		output(o, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
+		return 0;
+	}
+
+	/* Case #1: a is contained in b or vice versa */
+	if (in_merge_bases(commit_a, commit_b)) {
+		oidcpy(result, b);
+		if (show(o, 3)) {
+			output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
+			output_commit_title(o, commit_b);
+		} else if (show(o, 2))
+			output(o, 2, _("Fast-forwarding submodule %s to %s"), path, oid_to_hex(b));
+		else
+			; /* no output */
+
+		return 1;
+	}
+	if (in_merge_bases(commit_b, commit_a)) {
+		oidcpy(result, a);
+		if (show(o, 3)) {
+			output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
+			output_commit_title(o, commit_a);
+		} else if (show(o, 2))
+			output(o, 2, _("Fast-forwarding submodule %s to %s"), path, oid_to_hex(a));
+		else
+			; /* no output */
+
+		return 1;
+	}
+
+	/*
+	 * Case #2: There are one or more merges that contain a and b in
+	 * the submodule. If there is only one, then present it as a
+	 * suggestion to the user, but leave it marked unmerged so the
+	 * user needs to confirm the resolution.
+	 */
+
+	/* Skip the search if makes no sense to the calling context.  */
+	if (!search)
+		return 0;
+
+	/* find commit which merges them */
+	parent_count = find_first_merges(&merges, path, commit_a, commit_b);
+	switch (parent_count) {
+	case 0:
+		output(o, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
+		break;
+
+	case 1:
+		output(o, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
+		output(o, 2, _("Found a possible merge resolution for the submodule:\n"));
+		print_commit((struct commit *) merges.objects[0].item);
+		output(o, 2, _(
+			"If this is correct simply add it to the index "
+			"for example\n"
+			"by using:\n\n"
+			"  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
+			"which will accept this suggestion.\n"),
+			oid_to_hex(&merges.objects[0].item->oid), path);
+		break;
+
+	default:
+		output(o, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
+		for (i = 0; i < merges.nr; i++)
+			print_commit((struct commit *) merges.objects[i].item);
+	}
+
+	object_array_clear(&merges);
+	return 0;
+}
+
 static int merge_file_1(struct merge_options *o,
-					   const struct diff_filespec *one,
-					   const struct diff_filespec *a,
-					   const struct diff_filespec *b,
-					   const char *branch1,
-					   const char *branch2,
-					   struct merge_file_info *result)
+			const struct diff_filespec *one,
+			const struct diff_filespec *a,
+			const struct diff_filespec *b,
+			const char *filename,
+			const char *branch1,
+			const char *branch2,
+			struct merge_file_info *result)
 {
 	result->merge = 0;
 	result->clean = 1;
@@ -1039,12 +1331,11 @@
 				return ret;
 			result->clean = (merge_status == 0);
 		} else if (S_ISGITLINK(a->mode)) {
-			result->clean = merge_submodule(&result->oid,
+			result->clean = merge_submodule(o, &result->oid,
 						       one->path,
 						       &one->oid,
 						       &a->oid,
-						       &b->oid,
-						       !o->call_depth);
+						       &b->oid);
 		} else if (S_ISLNK(a->mode)) {
 			switch (o->recursive_variant) {
 			case MERGE_RECURSIVE_NORMAL:
@@ -1060,21 +1351,25 @@
 				break;
 			}
 		} else
-			die("BUG: unsupported object type in the tree");
+			BUG("unsupported object type in the tree");
 	}
 
+	if (result->merge)
+		output(o, 2, _("Auto-merging %s"), filename);
+
 	return 0;
 }
 
 static int merge_file_special_markers(struct merge_options *o,
-			   const struct diff_filespec *one,
-			   const struct diff_filespec *a,
-			   const struct diff_filespec *b,
-			   const char *branch1,
-			   const char *filename1,
-			   const char *branch2,
-			   const char *filename2,
-			   struct merge_file_info *mfi)
+				      const struct diff_filespec *one,
+				      const struct diff_filespec *a,
+				      const struct diff_filespec *b,
+				      const char *target_filename,
+				      const char *branch1,
+				      const char *filename1,
+				      const char *branch2,
+				      const char *filename2,
+				      struct merge_file_info *mfi)
 {
 	char *side1 = NULL;
 	char *side2 = NULL;
@@ -1085,22 +1380,23 @@
 	if (filename2)
 		side2 = xstrfmt("%s:%s", branch2, filename2);
 
-	ret = merge_file_1(o, one, a, b,
+	ret = merge_file_1(o, one, a, b, target_filename,
 			   side1 ? side1 : branch1,
 			   side2 ? side2 : branch2, mfi);
+
 	free(side1);
 	free(side2);
 	return ret;
 }
 
 static int merge_file_one(struct merge_options *o,
-					 const char *path,
-					 const struct object_id *o_oid, int o_mode,
-					 const struct object_id *a_oid, int a_mode,
-					 const struct object_id *b_oid, int b_mode,
-					 const char *branch1,
-					 const char *branch2,
-					 struct merge_file_info *mfi)
+			  const char *path,
+			  const struct object_id *o_oid, int o_mode,
+			  const struct object_id *a_oid, int a_mode,
+			  const struct object_id *b_oid, int b_mode,
+			  const char *branch1,
+			  const char *branch2,
+			  struct merge_file_info *mfi)
 {
 	struct diff_filespec one, a, b;
 
@@ -1111,7 +1407,39 @@
 	a.mode = a_mode;
 	oidcpy(&b.oid, b_oid);
 	b.mode = b_mode;
-	return merge_file_1(o, &one, &a, &b, branch1, branch2, mfi);
+	return merge_file_1(o, &one, &a, &b, path, branch1, branch2, mfi);
+}
+
+static int conflict_rename_dir(struct merge_options *o,
+			       struct diff_filepair *pair,
+			       const char *rename_branch,
+			       const char *other_branch)
+{
+	const struct diff_filespec *dest = pair->two;
+
+	if (!o->call_depth && would_lose_untracked(dest->path)) {
+		char *alt_path = unique_path(o, dest->path, rename_branch);
+
+		output(o, 1, _("Error: Refusing to lose untracked file at %s; "
+			       "writing to %s instead."),
+		       dest->path, alt_path);
+		/*
+		 * Write the file in worktree at alt_path, but not in the
+		 * index.  Instead, write to dest->path for the index but
+		 * only at the higher appropriate stage.
+		 */
+		if (update_file(o, 0, &dest->oid, dest->mode, alt_path))
+			return -1;
+		free(alt_path);
+		return update_stages(o, dest->path, NULL,
+				     rename_branch == o->branch1 ? dest : NULL,
+				     rename_branch == o->branch1 ? NULL : dest);
+	}
+
+	/* Update dest->path both in index and in worktree */
+	if (update_file(o, 1, &dest->oid, dest->mode, dest->path))
+		return -1;
+	return 0;
 }
 
 static int handle_change_delete(struct merge_options *o,
@@ -1127,7 +1455,8 @@
 	const char *update_path = path;
 	int ret = 0;
 
-	if (dir_in_way(path, !o->call_depth, 0)) {
+	if (dir_in_way(path, !o->call_depth, 0) ||
+	    (!o->call_depth && would_lose_untracked(path))) {
 		update_path = alt_path = unique_path(o, path, change_branch);
 	}
 
@@ -1242,17 +1571,34 @@
 
 	add = filespec_from_entry(&other, dst_entry, stage ^ 1);
 	if (add) {
+		int ren_src_was_dirty = was_dirty(o, rename->path);
 		char *add_name = unique_path(o, rename->path, other_branch);
 		if (update_file(o, 0, &add->oid, add->mode, add_name))
 			return -1;
 
-		remove_file(o, 0, rename->path, 0);
+		if (ren_src_was_dirty) {
+			output(o, 1, _("Refusing to lose dirty file at %s"),
+			       rename->path);
+		}
+		/*
+		 * Because the double negatives somehow keep confusing me...
+		 *    1) update_wd iff !ren_src_was_dirty.
+		 *    2) no_wd iff !update_wd
+		 *    3) so, no_wd == !!ren_src_was_dirty == ren_src_was_dirty
+		 */
+		remove_file(o, 0, rename->path, ren_src_was_dirty);
 		dst_name = unique_path(o, rename->path, cur_branch);
 	} else {
 		if (dir_in_way(rename->path, !o->call_depth, 0)) {
 			dst_name = unique_path(o, rename->path, cur_branch);
 			output(o, 1, _("%s is a directory in %s adding as %s instead"),
 			       rename->path, other_branch, dst_name);
+		} else if (!o->call_depth &&
+			   would_lose_untracked(rename->path)) {
+			dst_name = unique_path(o, rename->path, cur_branch);
+			output(o, 1, _("Refusing to lose untracked file at %s; "
+				       "adding as %s instead"),
+			       rename->path, dst_name);
 		}
 	}
 	if ((ret = update_file(o, 0, &rename->oid, rename->mode, dst_name)))
@@ -1339,6 +1685,8 @@
 	struct diff_filespec *c1 = ci->pair1->two;
 	struct diff_filespec *c2 = ci->pair2->two;
 	char *path = c1->path; /* == c2->path */
+	char *path_side_1_desc;
+	char *path_side_2_desc;
 	struct merge_file_info mfi_c1;
 	struct merge_file_info mfi_c2;
 	int ret;
@@ -1352,13 +1700,19 @@
 	remove_file(o, 1, a->path, o->call_depth || would_lose_untracked(a->path));
 	remove_file(o, 1, b->path, o->call_depth || would_lose_untracked(b->path));
 
+	path_side_1_desc = xstrfmt("%s (was %s)", path, a->path);
+	path_side_2_desc = xstrfmt("%s (was %s)", path, b->path);
 	if (merge_file_special_markers(o, a, c1, &ci->ren1_other,
+				       path_side_1_desc,
 				       o->branch1, c1->path,
 				       o->branch2, ci->ren1_other.path, &mfi_c1) ||
 	    merge_file_special_markers(o, b, &ci->ren2_other, c2,
+				       path_side_2_desc,
 				       o->branch1, ci->ren2_other.path,
 				       o->branch2, c2->path, &mfi_c2))
 		return -1;
+	free(path_side_1_desc);
+	free(path_side_2_desc);
 
 	if (o->call_depth) {
 		/*
@@ -1378,11 +1732,43 @@
 		char *new_path2 = unique_path(o, path, ci->branch2);
 		output(o, 1, _("Renaming %s to %s and %s to %s instead"),
 		       a->path, new_path1, b->path, new_path2);
-		remove_file(o, 0, path, 0);
+		if (was_dirty(o, path))
+			output(o, 1, _("Refusing to lose dirty file at %s"),
+			       path);
+		else if (would_lose_untracked(path))
+			/*
+			 * Only way we get here is if both renames were from
+			 * a directory rename AND user had an untracked file
+			 * at the location where both files end up after the
+			 * two directory renames.  See testcase 10d of t6043.
+			 */
+			output(o, 1, _("Refusing to lose untracked file at "
+				       "%s, even though it's in the way."),
+			       path);
+		else
+			remove_file(o, 0, path, 0);
 		ret = update_file(o, 0, &mfi_c1.oid, mfi_c1.mode, new_path1);
 		if (!ret)
 			ret = update_file(o, 0, &mfi_c2.oid, mfi_c2.mode,
 					  new_path2);
+		/*
+		 * unpack_trees() actually populates the index for us for
+		 * "normal" rename/rename(2to1) situtations so that the
+		 * correct entries are at the higher stages, which would
+		 * make the call below to update_stages_for_stage_data
+		 * unnecessary.  However, if either of the renames came
+		 * from a directory rename, then unpack_trees() will not
+		 * have gotten the right data loaded into the index, so we
+		 * need to do so now.  (While it'd be tempting to move this
+		 * call to update_stages_for_stage_data() to
+		 * apply_directory_rename_modifications(), that would break
+		 * our intermediate calls to would_lose_untracked() since
+		 * those rely on the current in-memory index.  See also the
+		 * big "NOTE" in update_stages()).
+		 */
+		if (update_stages_for_stage_data(o, path, ci->dst_entry1))
+			ret = -1;
+
 		free(new_path2);
 		free(new_path1);
 	}
@@ -1390,6 +1776,762 @@
 	return ret;
 }
 
+/*
+ * Get the diff_filepairs changed between o_tree and tree.
+ */
+static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
+					       struct tree *o_tree,
+					       struct tree *tree)
+{
+	struct diff_queue_struct *ret;
+	struct diff_options opts;
+
+	diff_setup(&opts);
+	opts.flags.recursive = 1;
+	opts.flags.rename_empty = 0;
+	opts.detect_rename = merge_detect_rename(o);
+	/*
+	 * We do not have logic to handle the detection of copies.  In
+	 * fact, it may not even make sense to add such logic: would we
+	 * really want a change to a base file to be propagated through
+	 * multiple other files by a merge?
+	 */
+	if (opts.detect_rename > DIFF_DETECT_RENAME)
+		opts.detect_rename = DIFF_DETECT_RENAME;
+	opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
+			    o->diff_rename_limit >= 0 ? o->diff_rename_limit :
+			    1000;
+	opts.rename_score = o->rename_score;
+	opts.show_rename_progress = o->show_rename_progress;
+	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+	diff_setup_done(&opts);
+	diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
+	diffcore_std(&opts);
+	if (opts.needed_rename_limit > o->needed_rename_limit)
+		o->needed_rename_limit = opts.needed_rename_limit;
+
+	ret = xmalloc(sizeof(*ret));
+	*ret = diff_queued_diff;
+
+	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+	diff_queued_diff.nr = 0;
+	diff_queued_diff.queue = NULL;
+	diff_flush(&opts);
+	return ret;
+}
+
+static int tree_has_path(struct tree *tree, const char *path)
+{
+	struct object_id hashy;
+	unsigned int mode_o;
+
+	return !get_tree_entry(&tree->object.oid, path,
+			       &hashy, &mode_o);
+}
+
+/*
+ * Return a new string that replaces the beginning portion (which matches
+ * entry->dir), with entry->new_dir.  In perl-speak:
+ *   new_path_name = (old_path =~ s/entry->dir/entry->new_dir/);
+ * NOTE:
+ *   Caller must ensure that old_path starts with entry->dir + '/'.
+ */
+static char *apply_dir_rename(struct dir_rename_entry *entry,
+			      const char *old_path)
+{
+	struct strbuf new_path = STRBUF_INIT;
+	int oldlen, newlen;
+
+	if (entry->non_unique_new_dir)
+		return NULL;
+
+	oldlen = strlen(entry->dir);
+	newlen = entry->new_dir.len + (strlen(old_path) - oldlen) + 1;
+	strbuf_grow(&new_path, newlen);
+	strbuf_addbuf(&new_path, &entry->new_dir);
+	strbuf_addstr(&new_path, &old_path[oldlen]);
+
+	return strbuf_detach(&new_path, NULL);
+}
+
+static void get_renamed_dir_portion(const char *old_path, const char *new_path,
+				    char **old_dir, char **new_dir)
+{
+	char *end_of_old, *end_of_new;
+	int old_len, new_len;
+
+	*old_dir = NULL;
+	*new_dir = NULL;
+
+	/*
+	 * For
+	 *    "a/b/c/d/e/foo.c" -> "a/b/some/thing/else/e/foo.c"
+	 * the "e/foo.c" part is the same, we just want to know that
+	 *    "a/b/c/d" was renamed to "a/b/some/thing/else"
+	 * so, for this example, this function returns "a/b/c/d" in
+	 * *old_dir and "a/b/some/thing/else" in *new_dir.
+	 *
+	 * Also, if the basename of the file changed, we don't care.  We
+	 * want to know which portion of the directory, if any, changed.
+	 */
+	end_of_old = strrchr(old_path, '/');
+	end_of_new = strrchr(new_path, '/');
+
+	if (end_of_old == NULL || end_of_new == NULL)
+		return;
+	while (*--end_of_new == *--end_of_old &&
+	       end_of_old != old_path &&
+	       end_of_new != new_path)
+		; /* Do nothing; all in the while loop */
+	/*
+	 * We've found the first non-matching character in the directory
+	 * paths.  That means the current directory we were comparing
+	 * represents the rename.  Move end_of_old and end_of_new back
+	 * to the full directory name.
+	 */
+	if (*end_of_old == '/')
+		end_of_old++;
+	if (*end_of_old != '/')
+		end_of_new++;
+	end_of_old = strchr(end_of_old, '/');
+	end_of_new = strchr(end_of_new, '/');
+
+	/*
+	 * It may have been the case that old_path and new_path were the same
+	 * directory all along.  Don't claim a rename if they're the same.
+	 */
+	old_len = end_of_old - old_path;
+	new_len = end_of_new - new_path;
+
+	if (old_len != new_len || strncmp(old_path, new_path, old_len)) {
+		*old_dir = xstrndup(old_path, old_len);
+		*new_dir = xstrndup(new_path, new_len);
+	}
+}
+
+static void remove_hashmap_entries(struct hashmap *dir_renames,
+				   struct string_list *items_to_remove)
+{
+	int i;
+	struct dir_rename_entry *entry;
+
+	for (i = 0; i < items_to_remove->nr; i++) {
+		entry = items_to_remove->items[i].util;
+		hashmap_remove(dir_renames, entry, NULL);
+	}
+	string_list_clear(items_to_remove, 0);
+}
+
+/*
+ * See if there is a directory rename for path, and if there are any file
+ * level conflicts for the renamed location.  If there is a rename and
+ * there are no conflicts, return the new name.  Otherwise, return NULL.
+ */
+static char *handle_path_level_conflicts(struct merge_options *o,
+					 const char *path,
+					 struct dir_rename_entry *entry,
+					 struct hashmap *collisions,
+					 struct tree *tree)
+{
+	char *new_path = NULL;
+	struct collision_entry *collision_ent;
+	int clean = 1;
+	struct strbuf collision_paths = STRBUF_INIT;
+
+	/*
+	 * entry has the mapping of old directory name to new directory name
+	 * that we want to apply to path.
+	 */
+	new_path = apply_dir_rename(entry, path);
+
+	if (!new_path) {
+		/* This should only happen when entry->non_unique_new_dir set */
+		if (!entry->non_unique_new_dir)
+			BUG("entry->non_unqiue_dir not set and !new_path");
+		output(o, 1, _("CONFLICT (directory rename split): "
+			       "Unclear where to place %s because directory "
+			       "%s was renamed to multiple other directories, "
+			       "with no destination getting a majority of the "
+			       "files."),
+		       path, entry->dir);
+		clean = 0;
+		return NULL;
+	}
+
+	/*
+	 * The caller needs to have ensured that it has pre-populated
+	 * collisions with all paths that map to new_path.  Do a quick check
+	 * to ensure that's the case.
+	 */
+	collision_ent = collision_find_entry(collisions, new_path);
+	if (collision_ent == NULL)
+		BUG("collision_ent is NULL");
+
+	/*
+	 * Check for one-sided add/add/.../add conflicts, i.e.
+	 * where implicit renames from the other side doing
+	 * directory rename(s) can affect this side of history
+	 * to put multiple paths into the same location.  Warn
+	 * and bail on directory renames for such paths.
+	 */
+	if (collision_ent->reported_already) {
+		clean = 0;
+	} else if (tree_has_path(tree, new_path)) {
+		collision_ent->reported_already = 1;
+		strbuf_add_separated_string_list(&collision_paths, ", ",
+						 &collision_ent->source_files);
+		output(o, 1, _("CONFLICT (implicit dir rename): Existing "
+			       "file/dir at %s in the way of implicit "
+			       "directory rename(s) putting the following "
+			       "path(s) there: %s."),
+		       new_path, collision_paths.buf);
+		clean = 0;
+	} else if (collision_ent->source_files.nr > 1) {
+		collision_ent->reported_already = 1;
+		strbuf_add_separated_string_list(&collision_paths, ", ",
+						 &collision_ent->source_files);
+		output(o, 1, _("CONFLICT (implicit dir rename): Cannot map "
+			       "more than one path to %s; implicit directory "
+			       "renames tried to put these paths there: %s"),
+		       new_path, collision_paths.buf);
+		clean = 0;
+	}
+
+	/* Free memory we no longer need */
+	strbuf_release(&collision_paths);
+	if (!clean && new_path) {
+		free(new_path);
+		return NULL;
+	}
+
+	return new_path;
+}
+
+/*
+ * There are a couple things we want to do at the directory level:
+ *   1. Check for both sides renaming to the same thing, in order to avoid
+ *      implicit renaming of files that should be left in place.  (See
+ *      testcase 6b in t6043 for details.)
+ *   2. Prune directory renames if there are still files left in the
+ *      the original directory.  These represent a partial directory rename,
+ *      i.e. a rename where only some of the files within the directory
+ *      were renamed elsewhere.  (Technically, this could be done earlier
+ *      in get_directory_renames(), except that would prevent us from
+ *      doing the previous check and thus failing testcase 6b.)
+ *   3. Check for rename/rename(1to2) conflicts (at the directory level).
+ *      In the future, we could potentially record this info as well and
+ *      omit reporting rename/rename(1to2) conflicts for each path within
+ *      the affected directories, thus cleaning up the merge output.
+ *   NOTE: We do NOT check for rename/rename(2to1) conflicts at the
+ *         directory level, because merging directories is fine.  If it
+ *         causes conflicts for files within those merged directories, then
+ *         that should be detected at the individual path level.
+ */
+static void handle_directory_level_conflicts(struct merge_options *o,
+					     struct hashmap *dir_re_head,
+					     struct tree *head,
+					     struct hashmap *dir_re_merge,
+					     struct tree *merge)
+{
+	struct hashmap_iter iter;
+	struct dir_rename_entry *head_ent;
+	struct dir_rename_entry *merge_ent;
+
+	struct string_list remove_from_head = STRING_LIST_INIT_NODUP;
+	struct string_list remove_from_merge = STRING_LIST_INIT_NODUP;
+
+	hashmap_iter_init(dir_re_head, &iter);
+	while ((head_ent = hashmap_iter_next(&iter))) {
+		merge_ent = dir_rename_find_entry(dir_re_merge, head_ent->dir);
+		if (merge_ent &&
+		    !head_ent->non_unique_new_dir &&
+		    !merge_ent->non_unique_new_dir &&
+		    !strbuf_cmp(&head_ent->new_dir, &merge_ent->new_dir)) {
+			/* 1. Renamed identically; remove it from both sides */
+			string_list_append(&remove_from_head,
+					   head_ent->dir)->util = head_ent;
+			strbuf_release(&head_ent->new_dir);
+			string_list_append(&remove_from_merge,
+					   merge_ent->dir)->util = merge_ent;
+			strbuf_release(&merge_ent->new_dir);
+		} else if (tree_has_path(head, head_ent->dir)) {
+			/* 2. This wasn't a directory rename after all */
+			string_list_append(&remove_from_head,
+					   head_ent->dir)->util = head_ent;
+			strbuf_release(&head_ent->new_dir);
+		}
+	}
+
+	remove_hashmap_entries(dir_re_head, &remove_from_head);
+	remove_hashmap_entries(dir_re_merge, &remove_from_merge);
+
+	hashmap_iter_init(dir_re_merge, &iter);
+	while ((merge_ent = hashmap_iter_next(&iter))) {
+		head_ent = dir_rename_find_entry(dir_re_head, merge_ent->dir);
+		if (tree_has_path(merge, merge_ent->dir)) {
+			/* 2. This wasn't a directory rename after all */
+			string_list_append(&remove_from_merge,
+					   merge_ent->dir)->util = merge_ent;
+		} else if (head_ent &&
+			   !head_ent->non_unique_new_dir &&
+			   !merge_ent->non_unique_new_dir) {
+			/* 3. rename/rename(1to2) */
+			/*
+			 * We can assume it's not rename/rename(1to1) because
+			 * that was case (1), already checked above.  So we
+			 * know that head_ent->new_dir and merge_ent->new_dir
+			 * are different strings.
+			 */
+			output(o, 1, _("CONFLICT (rename/rename): "
+				       "Rename directory %s->%s in %s. "
+				       "Rename directory %s->%s in %s"),
+			       head_ent->dir, head_ent->new_dir.buf, o->branch1,
+			       head_ent->dir, merge_ent->new_dir.buf, o->branch2);
+			string_list_append(&remove_from_head,
+					   head_ent->dir)->util = head_ent;
+			strbuf_release(&head_ent->new_dir);
+			string_list_append(&remove_from_merge,
+					   merge_ent->dir)->util = merge_ent;
+			strbuf_release(&merge_ent->new_dir);
+		}
+	}
+
+	remove_hashmap_entries(dir_re_head, &remove_from_head);
+	remove_hashmap_entries(dir_re_merge, &remove_from_merge);
+}
+
+static struct hashmap *get_directory_renames(struct diff_queue_struct *pairs,
+					     struct tree *tree)
+{
+	struct hashmap *dir_renames;
+	struct hashmap_iter iter;
+	struct dir_rename_entry *entry;
+	int i;
+
+	/*
+	 * Typically, we think of a directory rename as all files from a
+	 * certain directory being moved to a target directory.  However,
+	 * what if someone first moved two files from the original
+	 * directory in one commit, and then renamed the directory
+	 * somewhere else in a later commit?  At merge time, we just know
+	 * that files from the original directory went to two different
+	 * places, and that the bulk of them ended up in the same place.
+	 * We want each directory rename to represent where the bulk of the
+	 * files from that directory end up; this function exists to find
+	 * where the bulk of the files went.
+	 *
+	 * The first loop below simply iterates through the list of file
+	 * renames, finding out how often each directory rename pair
+	 * possibility occurs.
+	 */
+	dir_renames = xmalloc(sizeof(*dir_renames));
+	dir_rename_init(dir_renames);
+	for (i = 0; i < pairs->nr; ++i) {
+		struct string_list_item *item;
+		int *count;
+		struct diff_filepair *pair = pairs->queue[i];
+		char *old_dir, *new_dir;
+
+		/* File not part of directory rename if it wasn't renamed */
+		if (pair->status != 'R')
+			continue;
+
+		get_renamed_dir_portion(pair->one->path, pair->two->path,
+					&old_dir,        &new_dir);
+		if (!old_dir)
+			/* Directory didn't change at all; ignore this one. */
+			continue;
+
+		entry = dir_rename_find_entry(dir_renames, old_dir);
+		if (!entry) {
+			entry = xmalloc(sizeof(*entry));
+			dir_rename_entry_init(entry, old_dir);
+			hashmap_put(dir_renames, entry);
+		} else {
+			free(old_dir);
+		}
+		item = string_list_lookup(&entry->possible_new_dirs, new_dir);
+		if (!item) {
+			item = string_list_insert(&entry->possible_new_dirs,
+						  new_dir);
+			item->util = xcalloc(1, sizeof(int));
+		} else {
+			free(new_dir);
+		}
+		count = item->util;
+		*count += 1;
+	}
+
+	/*
+	 * For each directory with files moved out of it, we find out which
+	 * target directory received the most files so we can declare it to
+	 * be the "winning" target location for the directory rename.  This
+	 * winner gets recorded in new_dir.  If there is no winner
+	 * (multiple target directories received the same number of files),
+	 * we set non_unique_new_dir.  Once we've determined the winner (or
+	 * that there is no winner), we no longer need possible_new_dirs.
+	 */
+	hashmap_iter_init(dir_renames, &iter);
+	while ((entry = hashmap_iter_next(&iter))) {
+		int max = 0;
+		int bad_max = 0;
+		char *best = NULL;
+
+		for (i = 0; i < entry->possible_new_dirs.nr; i++) {
+			int *count = entry->possible_new_dirs.items[i].util;
+
+			if (*count == max)
+				bad_max = max;
+			else if (*count > max) {
+				max = *count;
+				best = entry->possible_new_dirs.items[i].string;
+			}
+		}
+		if (bad_max == max)
+			entry->non_unique_new_dir = 1;
+		else {
+			assert(entry->new_dir.len == 0);
+			strbuf_addstr(&entry->new_dir, best);
+		}
+		/*
+		 * The relevant directory sub-portion of the original full
+		 * filepaths were xstrndup'ed before inserting into
+		 * possible_new_dirs, and instead of manually iterating the
+		 * list and free'ing each, just lie and tell
+		 * possible_new_dirs that it did the strdup'ing so that it
+		 * will free them for us.
+		 */
+		entry->possible_new_dirs.strdup_strings = 1;
+		string_list_clear(&entry->possible_new_dirs, 1);
+	}
+
+	return dir_renames;
+}
+
+static struct dir_rename_entry *check_dir_renamed(const char *path,
+						  struct hashmap *dir_renames)
+{
+	char temp[PATH_MAX];
+	char *end;
+	struct dir_rename_entry *entry;
+
+	strcpy(temp, path);
+	while ((end = strrchr(temp, '/'))) {
+		*end = '\0';
+		entry = dir_rename_find_entry(dir_renames, temp);
+		if (entry)
+			return entry;
+	}
+	return NULL;
+}
+
+static void compute_collisions(struct hashmap *collisions,
+			       struct hashmap *dir_renames,
+			       struct diff_queue_struct *pairs)
+{
+	int i;
+
+	/*
+	 * Multiple files can be mapped to the same path due to directory
+	 * renames done by the other side of history.  Since that other
+	 * side of history could have merged multiple directories into one,
+	 * if our side of history added the same file basename to each of
+	 * those directories, then all N of them would get implicitly
+	 * renamed by the directory rename detection into the same path,
+	 * and we'd get an add/add/.../add conflict, and all those adds
+	 * from *this* side of history.  This is not representable in the
+	 * index, and users aren't going to easily be able to make sense of
+	 * it.  So we need to provide a good warning about what's
+	 * happening, and fall back to no-directory-rename detection
+	 * behavior for those paths.
+	 *
+	 * See testcases 9e and all of section 5 from t6043 for examples.
+	 */
+	collision_init(collisions);
+
+	for (i = 0; i < pairs->nr; ++i) {
+		struct dir_rename_entry *dir_rename_ent;
+		struct collision_entry *collision_ent;
+		char *new_path;
+		struct diff_filepair *pair = pairs->queue[i];
+
+		if (pair->status != 'A' && pair->status != 'R')
+			continue;
+		dir_rename_ent = check_dir_renamed(pair->two->path,
+						   dir_renames);
+		if (!dir_rename_ent)
+			continue;
+
+		new_path = apply_dir_rename(dir_rename_ent, pair->two->path);
+		if (!new_path)
+			/*
+			 * dir_rename_ent->non_unique_new_path is true, which
+			 * means there is no directory rename for us to use,
+			 * which means it won't cause us any additional
+			 * collisions.
+			 */
+			continue;
+		collision_ent = collision_find_entry(collisions, new_path);
+		if (!collision_ent) {
+			collision_ent = xcalloc(1,
+						sizeof(struct collision_entry));
+			hashmap_entry_init(collision_ent, strhash(new_path));
+			hashmap_put(collisions, collision_ent);
+			collision_ent->target_file = new_path;
+		} else {
+			free(new_path);
+		}
+		string_list_insert(&collision_ent->source_files,
+				   pair->two->path);
+	}
+}
+
+static char *check_for_directory_rename(struct merge_options *o,
+					const char *path,
+					struct tree *tree,
+					struct hashmap *dir_renames,
+					struct hashmap *dir_rename_exclusions,
+					struct hashmap *collisions,
+					int *clean_merge)
+{
+	char *new_path = NULL;
+	struct dir_rename_entry *entry = check_dir_renamed(path, dir_renames);
+	struct dir_rename_entry *oentry = NULL;
+
+	if (!entry)
+		return new_path;
+
+	/*
+	 * This next part is a little weird.  We do not want to do an
+	 * implicit rename into a directory we renamed on our side, because
+	 * that will result in a spurious rename/rename(1to2) conflict.  An
+	 * example:
+	 *   Base commit: dumbdir/afile, otherdir/bfile
+	 *   Side 1:      smrtdir/afile, otherdir/bfile
+	 *   Side 2:      dumbdir/afile, dumbdir/bfile
+	 * Here, while working on Side 1, we could notice that otherdir was
+	 * renamed/merged to dumbdir, and change the diff_filepair for
+	 * otherdir/bfile into a rename into dumbdir/bfile.  However, Side
+	 * 2 will notice the rename from dumbdir to smrtdir, and do the
+	 * transitive rename to move it from dumbdir/bfile to
+	 * smrtdir/bfile.  That gives us bfile in dumbdir vs being in
+	 * smrtdir, a rename/rename(1to2) conflict.  We really just want
+	 * the file to end up in smrtdir.  And the way to achieve that is
+	 * to not let Side1 do the rename to dumbdir, since we know that is
+	 * the source of one of our directory renames.
+	 *
+	 * That's why oentry and dir_rename_exclusions is here.
+	 *
+	 * As it turns out, this also prevents N-way transient rename
+	 * confusion; See testcases 9c and 9d of t6043.
+	 */
+	oentry = dir_rename_find_entry(dir_rename_exclusions, entry->new_dir.buf);
+	if (oentry) {
+		output(o, 1, _("WARNING: Avoiding applying %s -> %s rename "
+			       "to %s, because %s itself was renamed."),
+		       entry->dir, entry->new_dir.buf, path, entry->new_dir.buf);
+	} else {
+		new_path = handle_path_level_conflicts(o, path, entry,
+						       collisions, tree);
+		*clean_merge &= (new_path != NULL);
+	}
+
+	return new_path;
+}
+
+static void apply_directory_rename_modifications(struct merge_options *o,
+						 struct diff_filepair *pair,
+						 char *new_path,
+						 struct rename *re,
+						 struct tree *tree,
+						 struct tree *o_tree,
+						 struct tree *a_tree,
+						 struct tree *b_tree,
+						 struct string_list *entries,
+						 int *clean)
+{
+	struct string_list_item *item;
+	int stage = (tree == a_tree ? 2 : 3);
+	int update_wd;
+
+	/*
+	 * In all cases where we can do directory rename detection,
+	 * unpack_trees() will have read pair->two->path into the
+	 * index and the working copy.  We need to remove it so that
+	 * we can instead place it at new_path.  It is guaranteed to
+	 * not be untracked (unpack_trees() would have errored out
+	 * saying the file would have been overwritten), but it might
+	 * be dirty, though.
+	 */
+	update_wd = !was_dirty(o, pair->two->path);
+	if (!update_wd)
+		output(o, 1, _("Refusing to lose dirty file at %s"),
+		       pair->two->path);
+	remove_file(o, 1, pair->two->path, !update_wd);
+
+	/* Find or create a new re->dst_entry */
+	item = string_list_lookup(entries, new_path);
+	if (item) {
+		/*
+		 * Since we're renaming on this side of history, and it's
+		 * due to a directory rename on the other side of history
+		 * (which we only allow when the directory in question no
+		 * longer exists on the other side of history), the
+		 * original entry for re->dst_entry is no longer
+		 * necessary...
+		 */
+		re->dst_entry->processed = 1;
+
+		/*
+		 * ...because we'll be using this new one.
+		 */
+		re->dst_entry = item->util;
+	} else {
+		/*
+		 * re->dst_entry is for the before-dir-rename path, and we
+		 * need it to hold information for the after-dir-rename
+		 * path.  Before creating a new entry, we need to mark the
+		 * old one as unnecessary (...unless it is shared by
+		 * src_entry, i.e. this didn't use to be a rename, in which
+		 * case we can just allow the normal processing to happen
+		 * for it).
+		 */
+		if (pair->status == 'R')
+			re->dst_entry->processed = 1;
+
+		re->dst_entry = insert_stage_data(new_path,
+						  o_tree, a_tree, b_tree,
+						  entries);
+		item = string_list_insert(entries, new_path);
+		item->util = re->dst_entry;
+	}
+
+	/*
+	 * Update the stage_data with the information about the path we are
+	 * moving into place.  That slot will be empty and available for us
+	 * to write to because of the collision checks in
+	 * handle_path_level_conflicts().  In other words,
+	 * re->dst_entry->stages[stage].oid will be the null_oid, so it's
+	 * open for us to write to.
+	 *
+	 * It may be tempting to actually update the index at this point as
+	 * well, using update_stages_for_stage_data(), but as per the big
+	 * "NOTE" in update_stages(), doing so will modify the current
+	 * in-memory index which will break calls to would_lose_untracked()
+	 * that we need to make.  Instead, we need to just make sure that
+	 * the various conflict_rename_*() functions update the index
+	 * explicitly rather than relying on unpack_trees() to have done it.
+	 */
+	get_tree_entry(&tree->object.oid,
+		       pair->two->path,
+		       &re->dst_entry->stages[stage].oid,
+		       &re->dst_entry->stages[stage].mode);
+
+	/* Update pair status */
+	if (pair->status == 'A') {
+		/*
+		 * Recording rename information for this add makes it look
+		 * like a rename/delete conflict.  Make sure we can
+		 * correctly handle this as an add that was moved to a new
+		 * directory instead of reporting a rename/delete conflict.
+		 */
+		re->add_turned_into_rename = 1;
+	}
+	/*
+	 * We don't actually look at pair->status again, but it seems
+	 * pedagogically correct to adjust it.
+	 */
+	pair->status = 'R';
+
+	/*
+	 * Finally, record the new location.
+	 */
+	pair->two->path = new_path;
+}
+
+/*
+ * Get information of all renames which occurred in 'pairs', making use of
+ * any implicit directory renames inferred from the other side of history.
+ * We need the three trees in the merge ('o_tree', 'a_tree' and 'b_tree')
+ * to be able to associate the correct cache entries with the rename
+ * information; tree is always equal to either a_tree or b_tree.
+ */
+static struct string_list *get_renames(struct merge_options *o,
+				       struct diff_queue_struct *pairs,
+				       struct hashmap *dir_renames,
+				       struct hashmap *dir_rename_exclusions,
+				       struct tree *tree,
+				       struct tree *o_tree,
+				       struct tree *a_tree,
+				       struct tree *b_tree,
+				       struct string_list *entries,
+				       int *clean_merge)
+{
+	int i;
+	struct hashmap collisions;
+	struct hashmap_iter iter;
+	struct collision_entry *e;
+	struct string_list *renames;
+
+	compute_collisions(&collisions, dir_renames, pairs);
+	renames = xcalloc(1, sizeof(struct string_list));
+
+	for (i = 0; i < pairs->nr; ++i) {
+		struct string_list_item *item;
+		struct rename *re;
+		struct diff_filepair *pair = pairs->queue[i];
+		char *new_path; /* non-NULL only with directory renames */
+
+		if (pair->status != 'A' && pair->status != 'R') {
+			diff_free_filepair(pair);
+			continue;
+		}
+		new_path = check_for_directory_rename(o, pair->two->path, tree,
+						      dir_renames,
+						      dir_rename_exclusions,
+						      &collisions,
+						      clean_merge);
+		if (pair->status != 'R' && !new_path) {
+			diff_free_filepair(pair);
+			continue;
+		}
+
+		re = xmalloc(sizeof(*re));
+		re->processed = 0;
+		re->add_turned_into_rename = 0;
+		re->pair = pair;
+		item = string_list_lookup(entries, re->pair->one->path);
+		if (!item)
+			re->src_entry = insert_stage_data(re->pair->one->path,
+					o_tree, a_tree, b_tree, entries);
+		else
+			re->src_entry = item->util;
+
+		item = string_list_lookup(entries, re->pair->two->path);
+		if (!item)
+			re->dst_entry = insert_stage_data(re->pair->two->path,
+					o_tree, a_tree, b_tree, entries);
+		else
+			re->dst_entry = item->util;
+		item = string_list_insert(renames, pair->one->path);
+		item->util = re;
+		if (new_path)
+			apply_directory_rename_modifications(o, pair, new_path,
+							     re, tree, o_tree,
+							     a_tree, b_tree,
+							     entries,
+							     clean_merge);
+	}
+
+	hashmap_iter_init(&collisions, &iter);
+	while ((e = hashmap_iter_next(&iter))) {
+		free(e->target_file);
+		string_list_clear(&e->source_files, 0);
+	}
+	hashmap_free(&collisions, 1);
+	return renames;
+}
+
 static int process_renames(struct merge_options *o,
 			   struct string_list *a_renames,
 			   struct string_list *b_renames)
@@ -1462,7 +2604,7 @@
 			const char *ren2_dst = ren2->pair->two->path;
 			enum rename_type rename_type;
 			if (strcmp(ren1_src, ren2_src) != 0)
-				die("BUG: ren1_src != ren2_src");
+				BUG("ren1_src != ren2_src");
 			ren2->dst_entry->processed = 1;
 			ren2->processed = 1;
 			if (strcmp(ren1_dst, ren2_dst) != 0) {
@@ -1496,7 +2638,7 @@
 			ren2 = lookup->util;
 			ren2_dst = ren2->pair->two->path;
 			if (strcmp(ren1_dst, ren2_dst) != 0)
-				die("BUG: ren1_dst != ren2_dst");
+				BUG("ren1_dst != ren2_dst");
 
 			clean_merge = 0;
 			ren2->processed = 1;
@@ -1538,7 +2680,7 @@
 			 * add-source case).
 			 */
 			remove_file(o, 1, ren1_src,
-				    renamed_stage == 2 || !was_tracked(ren1_src));
+				    renamed_stage == 2 || !was_tracked(o, ren1_src));
 
 			oidcpy(&src_other.oid,
 			       &ren1->src_entry->stages[other_stage].oid);
@@ -1548,7 +2690,19 @@
 			dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
 			try_merge = 0;
 
-			if (oid_eq(&src_other.oid, &null_oid)) {
+			if (oid_eq(&src_other.oid, &null_oid) &&
+			    ren1->add_turned_into_rename) {
+				setup_rename_conflict_info(RENAME_DIR,
+							   ren1->pair,
+							   NULL,
+							   branch1,
+							   branch2,
+							   ren1->dst_entry,
+							   NULL,
+							   o,
+							   NULL,
+							   NULL);
+			} else if (oid_eq(&src_other.oid, &null_oid)) {
 				setup_rename_conflict_info(RENAME_DELETE,
 							   ren1->pair,
 							   NULL,
@@ -1645,6 +2799,105 @@
 	return clean_merge;
 }
 
+struct rename_info {
+	struct string_list *head_renames;
+	struct string_list *merge_renames;
+};
+
+static void initial_cleanup_rename(struct diff_queue_struct *pairs,
+				   struct hashmap *dir_renames)
+{
+	struct hashmap_iter iter;
+	struct dir_rename_entry *e;
+
+	hashmap_iter_init(dir_renames, &iter);
+	while ((e = hashmap_iter_next(&iter))) {
+		free(e->dir);
+		strbuf_release(&e->new_dir);
+		/* possible_new_dirs already cleared in get_directory_renames */
+	}
+	hashmap_free(dir_renames, 1);
+	free(dir_renames);
+
+	free(pairs->queue);
+	free(pairs);
+}
+
+static int handle_renames(struct merge_options *o,
+			  struct tree *common,
+			  struct tree *head,
+			  struct tree *merge,
+			  struct string_list *entries,
+			  struct rename_info *ri)
+{
+	struct diff_queue_struct *head_pairs, *merge_pairs;
+	struct hashmap *dir_re_head, *dir_re_merge;
+	int clean = 1;
+
+	ri->head_renames = NULL;
+	ri->merge_renames = NULL;
+
+	if (!merge_detect_rename(o))
+		return 1;
+
+	head_pairs = get_diffpairs(o, common, head);
+	merge_pairs = get_diffpairs(o, common, merge);
+
+	dir_re_head = get_directory_renames(head_pairs, head);
+	dir_re_merge = get_directory_renames(merge_pairs, merge);
+
+	handle_directory_level_conflicts(o,
+					 dir_re_head, head,
+					 dir_re_merge, merge);
+
+	ri->head_renames  = get_renames(o, head_pairs,
+					dir_re_merge, dir_re_head, head,
+					common, head, merge, entries,
+					&clean);
+	if (clean < 0)
+		goto cleanup;
+	ri->merge_renames = get_renames(o, merge_pairs,
+					dir_re_head, dir_re_merge, merge,
+					common, head, merge, entries,
+					&clean);
+	if (clean < 0)
+		goto cleanup;
+	clean &= process_renames(o, ri->head_renames, ri->merge_renames);
+
+cleanup:
+	/*
+	 * Some cleanup is deferred until cleanup_renames() because the
+	 * data structures are still needed and referenced in
+	 * process_entry().  But there are a few things we can free now.
+	 */
+	initial_cleanup_rename(head_pairs, dir_re_head);
+	initial_cleanup_rename(merge_pairs, dir_re_merge);
+
+	return clean;
+}
+
+static void final_cleanup_rename(struct string_list *rename)
+{
+	const struct rename *re;
+	int i;
+
+	if (rename == NULL)
+		return;
+
+	for (i = 0; i < rename->nr; i++) {
+		re = rename->items[i].util;
+		diff_free_filepair(re->pair);
+	}
+	string_list_clear(rename, 1);
+	free(rename);
+}
+
+static void final_cleanup_renames(struct rename_info *re_info)
+{
+	final_cleanup_rename(re_info->head_renames);
+	final_cleanup_rename(re_info->merge_renames);
+}
+
 static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
 {
 	return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
@@ -1735,6 +2988,7 @@
 
 static int merge_content(struct merge_options *o,
 			 const char *path,
+			 int is_dirty,
 			 struct object_id *o_oid, int o_mode,
 			 struct object_id *a_oid, int a_mode,
 			 struct object_id *b_oid, int b_mode,
@@ -1775,29 +3029,26 @@
 			       S_ISGITLINK(pair1->two->mode)))
 			df_conflict_remains = 1;
 	}
-	if (merge_file_special_markers(o, &one, &a, &b,
+	if (merge_file_special_markers(o, &one, &a, &b, path,
 				       o->branch1, path1,
 				       o->branch2, path2, &mfi))
 		return -1;
 
-	if (mfi.clean && !df_conflict_remains &&
-	    oid_eq(&mfi.oid, a_oid) && mfi.mode == a_mode) {
-		int path_renamed_outside_HEAD;
+	/*
+	 * We can skip updating the working tree file iff:
+	 *   a) The merge is clean
+	 *   b) The merge matches what was in HEAD (content, mode, pathname)
+	 *   c) The target path is usable (i.e. not involved in D/F conflict)
+	 */
+	if (mfi.clean &&
+	    was_tracked_and_matches(o, path, &mfi.oid, mfi.mode) &&
+	    !df_conflict_remains) {
 		output(o, 3, _("Skipped %s (merged same as existing)"), path);
-		/*
-		 * The content merge resulted in the same file contents we
-		 * already had.  We can return early if those file contents
-		 * are recorded at the correct path (which may not be true
-		 * if the merge involves a rename).
-		 */
-		path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
-		if (!path_renamed_outside_HEAD) {
-			add_cacheinfo(o, mfi.mode, &mfi.oid, path,
-				      0, (!o->call_depth), 0);
-			return mfi.clean;
-		}
-	} else
-		output(o, 2, _("Auto-merging %s"), path);
+		if (add_cacheinfo(o, mfi.mode, &mfi.oid, path,
+				  0, (!o->call_depth && !is_dirty), 0))
+			return -1;
+		return mfi.clean;
+	}
 
 	if (!mfi.clean) {
 		if (S_ISGITLINK(mfi.mode))
@@ -1809,7 +3060,7 @@
 				return -1;
 	}
 
-	if (df_conflict_remains) {
+	if (df_conflict_remains || is_dirty) {
 		char *new_path;
 		if (o->call_depth) {
 			remove_file_from_cache(path);
@@ -1818,7 +3069,7 @@
 				if (update_stages(o, path, &one, &a, &b))
 					return -1;
 			} else {
-				int file_from_stage2 = was_tracked(path);
+				int file_from_stage2 = was_tracked(o, path);
 				struct diff_filespec merged;
 				oidcpy(&merged.oid, &mfi.oid);
 				merged.mode = mfi.mode;
@@ -1831,6 +3082,10 @@
 
 		}
 		new_path = unique_path(o, path, rename_conflict_info->branch1);
+		if (is_dirty) {
+			output(o, 1, _("Refusing to lose dirty file at %s"),
+			       path);
+		}
 		output(o, 1, _("Adding as %s instead"), new_path);
 		if (update_file(o, 0, &mfi.oid, mfi.mode, new_path)) {
 			free(new_path);
@@ -1840,7 +3095,20 @@
 		mfi.clean = 0;
 	} else if (update_file(o, mfi.clean, &mfi.oid, mfi.mode, path))
 		return -1;
-	return mfi.clean;
+	return !is_dirty && mfi.clean;
+}
+
+static int conflict_rename_normal(struct merge_options *o,
+				  const char *path,
+				  struct object_id *o_oid, unsigned int o_mode,
+				  struct object_id *a_oid, unsigned int a_mode,
+				  struct object_id *b_oid, unsigned int b_mode,
+				  struct rename_conflict_info *ci)
+{
+	/* Merge the content and write it out */
+	return merge_content(o, path, was_dirty(o, path),
+			     o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
+			     ci);
 }
 
 /* Per entry merge function */
@@ -1862,9 +3130,20 @@
 		switch (conflict_info->rename_type) {
 		case RENAME_NORMAL:
 		case RENAME_ONE_FILE_TO_ONE:
-			clean_merge = merge_content(o, path,
-						    o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
-						    conflict_info);
+			clean_merge = conflict_rename_normal(o,
+							     path,
+							     o_oid, o_mode,
+							     a_oid, a_mode,
+							     b_oid, b_mode,
+							     conflict_info);
+			break;
+		case RENAME_DIR:
+			clean_merge = 1;
+			if (conflict_rename_dir(o,
+						conflict_info->pair1,
+						conflict_info->branch1,
+						conflict_info->branch2))
+				clean_merge = -1;
 			break;
 		case RENAME_DELETE:
 			clean_merge = 0;
@@ -1952,7 +3231,8 @@
 	} else if (a_oid && b_oid) {
 		/* Case C: Added in both (check for same permissions) and */
 		/* case D: Modified in both, but differently. */
-		clean_merge = merge_content(o, path,
+		int is_dirty = 0; /* unpack_trees would have bailed if dirty */
+		clean_merge = merge_content(o, path, is_dirty,
 					    o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
 					    NULL);
 	} else if (!o_oid && !a_oid && !b_oid) {
@@ -1962,7 +3242,7 @@
 		 */
 		remove_file(o, 1, path, !a_mode);
 	} else
-		die("BUG: fatal merge failure, shouldn't happen.");
+		BUG("fatal merge failure, shouldn't happen.");
 
 	return clean_merge;
 }
@@ -1993,18 +3273,20 @@
 		return 1;
 	}
 
-	code = git_merge_trees(o->call_depth, common, head, merge);
+	code = unpack_trees_start(o, common, head, merge);
 
 	if (code != 0) {
 		if (show(o, 4) || o->call_depth)
 			err(o, _("merging of trees %s and %s failed"),
 			    oid_to_hex(&head->object.oid),
 			    oid_to_hex(&merge->object.oid));
+		unpack_trees_finish(o);
 		return -1;
 	}
 
 	if (unmerged_cache()) {
-		struct string_list *entries, *re_head, *re_merge;
+		struct string_list *entries;
+		struct rename_info re_info;
 		int i;
 		/*
 		 * Only need the hashmap while processing entries, so
@@ -2018,9 +3300,8 @@
 		get_files_dirs(o, merge);
 
 		entries = get_unmerged();
-		re_head  = get_renames(o, head, common, head, merge, entries);
-		re_merge = get_renames(o, merge, common, head, merge, entries);
-		clean = process_renames(o, re_head, re_merge);
+		clean = handle_renames(o, common, head, merge, entries,
+				       &re_info);
 		record_df_conflict_files(o, entries);
 		if (clean < 0)
 			goto cleanup;
@@ -2040,27 +3321,28 @@
 		for (i = 0; i < entries->nr; i++) {
 			struct stage_data *e = entries->items[i].util;
 			if (!e->processed)
-				die("BUG: unprocessed path??? %s",
+				BUG("unprocessed path??? %s",
 				    entries->items[i].string);
 		}
 
 cleanup:
-		string_list_clear(re_merge, 0);
-		string_list_clear(re_head, 0);
+		final_cleanup_renames(&re_info);
+
 		string_list_clear(entries, 1);
+		free(entries);
 
 		hashmap_free(&o->current_file_dir_set, 1);
 
-		free(re_merge);
-		free(re_head);
-		free(entries);
-
-		if (clean < 0)
+		if (clean < 0) {
+			unpack_trees_finish(o);
 			return clean;
+		}
 	}
 	else
 		clean = 1;
 
+	unpack_trees_finish(o);
+
 	if (o->call_depth && !(*result = write_tree_from_memory(o)))
 		return -1;
 
@@ -2154,7 +3436,8 @@
 		read_cache();
 
 	o->ancestor = "merged common ancestors";
-	clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
+	clean = merge_trees(o, get_commit_tree(h1), get_commit_tree(h2),
+			    get_commit_tree(merged_common_ancestors),
 			    &mrtree);
 	if (clean < 0) {
 		flush_output(o);
@@ -2232,9 +3515,18 @@
 
 static void merge_recursive_config(struct merge_options *o)
 {
+	char *value = NULL;
 	git_config_get_int("merge.verbosity", &o->verbosity);
 	git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
 	git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
+	if (!git_config_get_string("diff.renames", &value)) {
+		o->diff_detect_rename = git_config_rename("diff.renames", value);
+		free(value);
+	}
+	if (!git_config_get_string("merge.renames", &value)) {
+		o->merge_detect_rename = git_config_rename("merge.renames", value);
+		free(value);
+	}
 	git_config(git_xmerge_config, NULL);
 }
 
@@ -2247,7 +3539,8 @@
 	o->diff_rename_limit = -1;
 	o->merge_rename_limit = -1;
 	o->renormalize = 0;
-	o->detect_rename = 1;
+	o->diff_detect_rename = -1;
+	o->merge_detect_rename = -1;
 	merge_recursive_config(o);
 	merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
 	if (merge_verbosity)
@@ -2298,16 +3591,16 @@
 	else if (!strcmp(s, "no-renormalize"))
 		o->renormalize = 0;
 	else if (!strcmp(s, "no-renames"))
-		o->detect_rename = 0;
+		o->merge_detect_rename = 0;
 	else if (!strcmp(s, "find-renames")) {
-		o->detect_rename = 1;
+		o->merge_detect_rename = 1;
 		o->rename_score = 0;
 	}
 	else if (skip_prefix(s, "find-renames=", &arg) ||
 		 skip_prefix(s, "rename-threshold=", &arg)) {
 		if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
 			return -1;
-		o->detect_rename = 1;
+		o->merge_detect_rename = 1;
 	}
 	else
 		return -1;
diff --git a/merge-recursive.h b/merge-recursive.h
index 80d69d1..fa7bc6b 100644
--- a/merge-recursive.h
+++ b/merge-recursive.h
@@ -1,6 +1,7 @@
 #ifndef MERGE_RECURSIVE_H
 #define MERGE_RECURSIVE_H
 
+#include "unpack-trees.h"
 #include "string-list.h"
 
 struct merge_options {
@@ -17,7 +18,8 @@
 	unsigned renormalize : 1;
 	long xdl_opts;
 	int verbosity;
-	int detect_rename;
+	int diff_detect_rename;
+	int merge_detect_rename;
 	int diff_rename_limit;
 	int merge_rename_limit;
 	int rename_score;
@@ -27,8 +29,41 @@
 	struct strbuf obuf;
 	struct hashmap current_file_dir_set;
 	struct string_list df_conflict_file_set;
+	struct unpack_trees_options unpack_opts;
+	struct index_state orig_index;
 };
 
+/*
+ * For dir_rename_entry, directory names are stored as a full path from the
+ * toplevel of the repository and do not include a trailing '/'.  Also:
+ *
+ *   dir:                original name of directory being renamed
+ *   non_unique_new_dir: if true, could not determine new_dir
+ *   new_dir:            final name of directory being renamed
+ *   possible_new_dirs:  temporary used to help determine new_dir; see comments
+ *                       in get_directory_renames() for details
+ */
+struct dir_rename_entry {
+	struct hashmap_entry ent; /* must be the first member! */
+	char *dir;
+	unsigned non_unique_new_dir:1;
+	struct strbuf new_dir;
+	struct string_list possible_new_dirs;
+};
+
+struct collision_entry {
+	struct hashmap_entry ent; /* must be the first member! */
+	char *target_file;
+	struct string_list source_files;
+	unsigned reported_already:1;
+};
+
+static inline int merge_detect_rename(struct merge_options *o)
+{
+	return o->merge_detect_rename >= 0 ? o->merge_detect_rename :
+		o->diff_detect_rename >= 0 ? o->diff_detect_rename : 1;
+}
+
 /* merge_trees() but with recursive ancestor consolidation */
 int merge_recursive(struct merge_options *o,
 		    struct commit *h1,
diff --git a/merge.c b/merge.c
index f06a477..0783858 100644
--- a/merge.c
+++ b/merge.c
@@ -11,10 +11,7 @@
 
 static const char *merge_argument(struct commit *commit)
 {
-	if (commit)
-		return oid_to_hex(&commit->object.oid);
-	else
-		return EMPTY_TREE_SHA1_HEX;
+	return oid_to_hex(commit ? &commit->object.oid : the_hash_algo->empty_tree);
 }
 
 int index_has_changes(struct strbuf *sb)
@@ -94,8 +91,24 @@
 		return -1;
 
 	memset(&trees, 0, sizeof(trees));
-	memset(&opts, 0, sizeof(opts));
 	memset(&t, 0, sizeof(t));
+
+	trees[nr_trees] = parse_tree_indirect(head);
+	if (!trees[nr_trees++]) {
+		rollback_lock_file(&lock_file);
+		return -1;
+	}
+	trees[nr_trees] = parse_tree_indirect(remote);
+	if (!trees[nr_trees++]) {
+		rollback_lock_file(&lock_file);
+		return -1;
+	}
+	for (i = 0; i < nr_trees; i++) {
+		parse_tree(trees[i]);
+		init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
+	}
+
+	memset(&opts, 0, sizeof(opts));
 	if (overwrite_ignore) {
 		memset(&dir, 0, sizeof(dir));
 		dir.flags |= DIR_SHOW_IGNORED;
@@ -112,24 +125,13 @@
 	opts.fn = twoway_merge;
 	setup_unpack_trees_porcelain(&opts, "merge");
 
-	trees[nr_trees] = parse_tree_indirect(head);
-	if (!trees[nr_trees++]) {
-		rollback_lock_file(&lock_file);
-		return -1;
-	}
-	trees[nr_trees] = parse_tree_indirect(remote);
-	if (!trees[nr_trees++]) {
-		rollback_lock_file(&lock_file);
-		return -1;
-	}
-	for (i = 0; i < nr_trees; i++) {
-		parse_tree(trees[i]);
-		init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
-	}
 	if (unpack_trees(nr_trees, t, &opts)) {
 		rollback_lock_file(&lock_file);
+		clear_unpack_trees_porcelain(&opts);
 		return -1;
 	}
+	clear_unpack_trees_porcelain(&opts);
+
 	if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 		return error(_("unable to write new index file"));
 	return 0;
diff --git a/notes-merge.c b/notes-merge.c
index 8e0726a..d613e06 100644
--- a/notes-merge.c
+++ b/notes-merge.c
@@ -442,7 +442,7 @@
 			printf("Using remote notes for %s\n",
 						oid_to_hex(&p->obj));
 		if (add_note(t, &p->obj, &p->remote, combine_notes_overwrite))
-			die("BUG: combine_notes_overwrite failed");
+			BUG("combine_notes_overwrite failed");
 		return 0;
 	case NOTES_MERGE_RESOLVE_UNION:
 		if (o->verbosity >= 2)
@@ -490,7 +490,7 @@
 			trace_printf("\t\t\tno local change, adopted remote\n");
 			if (add_note(t, &p->obj, &p->remote,
 				     combine_notes_overwrite))
-				die("BUG: combine_notes_overwrite failed");
+				BUG("combine_notes_overwrite failed");
 		} else {
 			/* need file-level merge between local and remote */
 			trace_printf("\t\t\tneed content-level merge\n");
@@ -600,14 +600,14 @@
 			printf("No merge base found; doing history-less merge\n");
 	} else if (!bases->next) {
 		base_oid = &bases->item->object.oid;
-		base_tree_oid = &bases->item->tree->object.oid;
+		base_tree_oid = get_commit_tree_oid(bases->item);
 		if (o->verbosity >= 4)
 			printf("One merge base found (%.7s)\n",
 			       oid_to_hex(base_oid));
 	} else {
 		/* TODO: How to handle multiple merge-bases? */
 		base_oid = &bases->item->object.oid;
-		base_tree_oid = &bases->item->tree->object.oid;
+		base_tree_oid = get_commit_tree_oid(bases->item);
 		if (o->verbosity >= 3)
 			printf("Multiple merge bases found. Using the first "
 				"(%.7s)\n", oid_to_hex(base_oid));
@@ -634,8 +634,9 @@
 		goto found_result;
 	}
 
-	result = merge_from_diffs(o, base_tree_oid, &local->tree->object.oid,
-				  &remote->tree->object.oid, local_tree);
+	result = merge_from_diffs(o, base_tree_oid,
+				  get_commit_tree_oid(local),
+				  get_commit_tree_oid(remote), local_tree);
 
 	if (result != 0) { /* non-trivial merge (with or without conflicts) */
 		/* Commit (partial) result */
diff --git a/object-store.h b/object-store.h
index fef33f3..d683112 100644
--- a/object-store.h
+++ b/object-store.h
@@ -1,6 +1,8 @@
 #ifndef OBJECT_STORE_H
 #define OBJECT_STORE_H
 
+#include "oidmap.h"
+
 struct alternate_object_database {
 	struct alternate_object_database *next;
 
@@ -69,8 +71,10 @@
 	int index_version;
 	time_t mtime;
 	int pack_fd;
+	int index;              /* for builtin/pack-objects.c */
 	unsigned pack_local:1,
 		 pack_keep:1,
+		 pack_keep_in_core:1,
 		 freshened:1,
 		 do_not_close:1,
 		 pack_promisor:1;
@@ -94,6 +98,12 @@
 	struct alternate_object_database **alt_odb_tail;
 
 	/*
+	 * Objects that should be substituted by other objects
+	 * (see git-replace(1)).
+	 */
+	struct oidmap *replace_map;
+
+	/*
 	 * private data
 	 *
 	 * should only be accessed directly by packfile.c
diff --git a/object.c b/object.c
index a0a756f..f7f4de3 100644
--- a/object.c
+++ b/object.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "object.h"
+#include "replace-object.h"
 #include "blob.h"
 #include "tree.h"
 #include "commit.h"
@@ -246,7 +247,7 @@
 	unsigned long size;
 	enum object_type type;
 	int eaten;
-	const struct object_id *repl = lookup_replace_object(oid);
+	const struct object_id *repl = lookup_replace_object(the_repository, oid);
 	void *buffer;
 	struct object *obj;
 
@@ -256,7 +257,7 @@
 
 	if ((obj && obj->type == OBJ_BLOB && has_object_file(oid)) ||
 	    (!obj && has_object_file(oid) &&
-	     oid_object_info(oid, NULL) == OBJ_BLOB)) {
+	     oid_object_info(the_repository, oid, NULL) == OBJ_BLOB)) {
 		if (check_object_signature(repl, NULL, 0, NULL) < 0) {
 			error("sha1 mismatch %s", oid_to_hex(oid));
 			return NULL;
@@ -480,6 +481,9 @@
 	FREE_AND_NULL(o->objectdir);
 	FREE_AND_NULL(o->alternate_db);
 
+	oidmap_free(o->replace_map, 1);
+	FREE_AND_NULL(o->replace_map);
+
 	free_alt_odbs(o);
 	o->alt_odb_tail = NULL;
 
diff --git a/object.h b/object.h
index b8e70e5..5c13955 100644
--- a/object.h
+++ b/object.h
@@ -25,7 +25,6 @@
 
 #define OBJECT_ARRAY_INIT { 0, 0, NULL }
 
-#define TYPE_BITS   3
 /*
  * object flag allocation:
  * revision.h:               0---------10                                26
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index 41ae27f..7b2dc3e 100644
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -48,7 +48,8 @@
 /**
  * Build the initial type index for the packfile
  */
-void bitmap_writer_build_type_index(struct pack_idx_entry **index,
+void bitmap_writer_build_type_index(struct packing_data *to_pack,
+				    struct pack_idx_entry **index,
 				    uint32_t index_nr)
 {
 	uint32_t i;
@@ -57,23 +58,25 @@
 	writer.trees = ewah_new();
 	writer.blobs = ewah_new();
 	writer.tags = ewah_new();
+	ALLOC_ARRAY(to_pack->in_pack_pos, to_pack->nr_objects);
 
 	for (i = 0; i < index_nr; ++i) {
 		struct object_entry *entry = (struct object_entry *)index[i];
 		enum object_type real_type;
 
-		entry->in_pack_pos = i;
+		oe_set_in_pack_pos(to_pack, entry, i);
 
-		switch (entry->type) {
+		switch (oe_type(entry)) {
 		case OBJ_COMMIT:
 		case OBJ_TREE:
 		case OBJ_BLOB:
 		case OBJ_TAG:
-			real_type = entry->type;
+			real_type = oe_type(entry);
 			break;
 
 		default:
-			real_type = oid_object_info(&entry->idx.oid, NULL);
+			real_type = oid_object_info(the_repository,
+						    &entry->idx.oid, NULL);
 			break;
 		}
 
@@ -97,7 +100,7 @@
 		default:
 			die("Missing type information for %s (%d/%d)",
 			    oid_to_hex(&entry->idx.oid), real_type,
-			    entry->type);
+			    oe_type(entry));
 		}
 	}
 }
@@ -146,7 +149,7 @@
 			"(object %s is missing)", sha1_to_hex(sha1));
 	}
 
-	return entry->in_pack_pos;
+	return oe_in_pack_pos(writer.to_pack, entry);
 }
 
 static void show_object(struct object *object, const char *name, void *data)
@@ -474,7 +477,7 @@
 			sha1_pos(stored->commit->object.oid.hash, index, index_nr, sha1_access);
 
 		if (commit_pos < 0)
-			die("BUG: trying to write commit not in index");
+			BUG("trying to write commit not in index");
 
 		hashwrite_be32(f, commit_pos);
 		hashwrite_u8(f, stored->xor_offset);
@@ -534,7 +537,7 @@
 	if (options & BITMAP_OPT_HASH_CACHE)
 		write_hash_cache(f, index, index_nr);
 
-	hashclose(f, NULL, CSUM_FSYNC);
+	finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
 
 	if (adjust_shared_perm(tmp_file.buf))
 		die_errno("unable to make temporary bitmap file readable");
diff --git a/pack-bitmap.c b/pack-bitmap.c
index 3f2dab3..0677111 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -255,7 +255,7 @@
 	size_t len;
 
 	if (!strip_suffix(p->pack_name, ".pack", &len))
-		die("BUG: pack_name does not end in .pack");
+		BUG("pack_name does not end in .pack");
 	return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
 }
 
@@ -723,13 +723,13 @@
 		revs->ignore_missing_links = 0;
 
 		if (haves_bitmap == NULL)
-			die("BUG: failed to perform bitmap walk");
+			BUG("failed to perform bitmap walk");
 	}
 
 	wants_bitmap = find_objects(revs, wants, haves_bitmap);
 
 	if (!wants_bitmap)
-		die("BUG: failed to perform bitmap walk");
+		BUG("failed to perform bitmap walk");
 
 	if (haves_bitmap)
 		bitmap_and_not(wants_bitmap, haves_bitmap);
@@ -1033,7 +1033,7 @@
 		oe = packlist_find(mapping, sha1, NULL);
 
 		if (oe)
-			reposition[i] = oe->in_pack_pos + 1;
+			reposition[i] = oe_in_pack_pos(mapping, oe) + 1;
 	}
 
 	rebuild = bitmap_new();
diff --git a/pack-bitmap.h b/pack-bitmap.h
index 3742a00..5ded2f1 100644
--- a/pack-bitmap.h
+++ b/pack-bitmap.h
@@ -44,7 +44,9 @@
 
 void bitmap_writer_show_progress(int show);
 void bitmap_writer_set_checksum(unsigned char *sha1);
-void bitmap_writer_build_type_index(struct pack_idx_entry **index, uint32_t index_nr);
+void bitmap_writer_build_type_index(struct packing_data *to_pack,
+				    struct pack_idx_entry **index,
+				    uint32_t index_nr);
 void bitmap_writer_reuse_bitmaps(struct packing_data *to_pack);
 void bitmap_writer_select_commits(struct commit **indexed_commits,
 		unsigned int indexed_commits_nr, int max_bitmaps);
diff --git a/pack-check.c b/pack-check.c
index 385d964..d3a57df 100644
--- a/pack-check.c
+++ b/pack-check.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "repository.h"
 #include "pack.h"
 #include "pack-revindex.h"
 #include "progress.h"
@@ -134,7 +135,7 @@
 			data = NULL;
 			data_valid = 0;
 		} else {
-			data = unpack_entry(p, entries[i].offset, &type, &size);
+			data = unpack_entry(the_repository, p, entries[i].offset, &type, &size);
 			data_valid = 1;
 		}
 
diff --git a/pack-objects.c b/pack-objects.c
index 9558d13..9270852 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -2,6 +2,8 @@
 #include "object.h"
 #include "pack.h"
 #include "pack-objects.h"
+#include "packfile.h"
+#include "config.h"
 
 static uint32_t locate_object_entry_hash(struct packing_data *pdata,
 					 const unsigned char *sha1,
@@ -58,7 +60,7 @@
 						       &found);
 
 		if (found)
-			die("BUG: Duplicate object in hash");
+			BUG("Duplicate object in hash");
 
 		pdata->index[ix] = i + 1;
 		entry++;
@@ -86,6 +88,66 @@
 	return &pdata->objects[pdata->index[i] - 1];
 }
 
+static void prepare_in_pack_by_idx(struct packing_data *pdata)
+{
+	struct packed_git **mapping, *p;
+	int cnt = 0, nr = 1U << OE_IN_PACK_BITS;
+
+	ALLOC_ARRAY(mapping, nr);
+	/*
+	 * oe_in_pack() on an all-zero'd object_entry
+	 * (i.e. in_pack_idx also zero) should return NULL.
+	 */
+	mapping[cnt++] = NULL;
+	for (p = get_packed_git(the_repository); p; p = p->next, cnt++) {
+		if (cnt == nr) {
+			free(mapping);
+			return;
+		}
+		p->index = cnt;
+		mapping[cnt] = p;
+	}
+	pdata->in_pack_by_idx = mapping;
+}
+
+/*
+ * A new pack appears after prepare_in_pack_by_idx() has been
+ * run. This is likely a race.
+ *
+ * We could map this new pack to in_pack_by_idx[] array, but then we
+ * have to deal with full array anyway. And since it's hard to test
+ * this fall back code, just stay simple and fall back to using
+ * in_pack[] array.
+ */
+void oe_map_new_pack(struct packing_data *pack,
+		     struct packed_git *p)
+{
+	uint32_t i;
+
+	REALLOC_ARRAY(pack->in_pack, pack->nr_alloc);
+
+	for (i = 0; i < pack->nr_objects; i++)
+		pack->in_pack[i] = oe_in_pack(pack, pack->objects + i);
+
+	FREE_AND_NULL(pack->in_pack_by_idx);
+}
+
+/* assume pdata is already zero'd by caller */
+void prepare_packing_data(struct packing_data *pdata)
+{
+	if (git_env_bool("GIT_TEST_FULL_IN_PACK_ARRAY", 0)) {
+		/*
+		 * do not initialize in_pack_by_idx[] to force the
+		 * slow path in oe_in_pack()
+		 */
+	} else {
+		prepare_in_pack_by_idx(pdata);
+	}
+
+	pdata->oe_size_limit = git_env_ulong("GIT_TEST_OE_SIZE",
+					     1U << OE_SIZE_BITS);
+}
+
 struct object_entry *packlist_alloc(struct packing_data *pdata,
 				    const unsigned char *sha1,
 				    uint32_t index_pos)
@@ -95,6 +157,9 @@
 	if (pdata->nr_objects >= pdata->nr_alloc) {
 		pdata->nr_alloc = (pdata->nr_alloc  + 1024) * 3 / 2;
 		REALLOC_ARRAY(pdata->objects, pdata->nr_alloc);
+
+		if (!pdata->in_pack_by_idx)
+			REALLOC_ARRAY(pdata->in_pack, pdata->nr_alloc);
 	}
 
 	new_entry = pdata->objects + pdata->nr_objects++;
@@ -107,5 +172,8 @@
 	else
 		pdata->index[index_pos] = pdata->nr_objects;
 
+	if (pdata->in_pack)
+		pdata->in_pack[pdata->nr_objects - 1] = NULL;
+
 	return new_entry;
 }
diff --git a/pack-objects.h b/pack-objects.h
index 03f1191..edf74da 100644
--- a/pack-objects.h
+++ b/pack-objects.h
@@ -1,45 +1,125 @@
 #ifndef PACK_OBJECTS_H
 #define PACK_OBJECTS_H
 
+#include "object-store.h"
+
+#define DEFAULT_DELTA_CACHE_SIZE (256 * 1024 * 1024)
+
+#define OE_DFS_STATE_BITS	2
+#define OE_DEPTH_BITS		12
+#define OE_IN_PACK_BITS		10
+#define OE_Z_DELTA_BITS		20
+/*
+ * Note that oe_set_size() becomes expensive when the given size is
+ * above this limit. Don't lower it too much.
+ */
+#define OE_SIZE_BITS		31
+#define OE_DELTA_SIZE_BITS	20
+
+/*
+ * State flags for depth-first search used for analyzing delta cycles.
+ *
+ * The depth is measured in delta-links to the base (so if A is a delta
+ * against B, then A has a depth of 1, and B a depth of 0).
+ */
+enum dfs_state {
+	DFS_NONE = 0,
+	DFS_ACTIVE,
+	DFS_DONE,
+	DFS_NUM_STATES
+};
+
+/*
+ * The size of struct nearly determines pack-objects's memory
+ * consumption. This struct is packed tight for that reason. When you
+ * add or reorder something in this struct, think a bit about this.
+ *
+ * basic object info
+ * -----------------
+ * idx.oid is filled up before delta searching starts. idx.crc32 is
+ * only valid after the object is written out and will be used for
+ * generating the index. idx.offset will be both gradually set and
+ * used in writing phase (base objects get offset first, then deltas
+ * refer to them)
+ *
+ * "size" is the uncompressed object size. Compressed size of the raw
+ * data for an object in a pack is not stored anywhere but is computed
+ * and made available when reverse .idx is made. Note that when a
+ * delta is reused, "size" is the uncompressed _delta_ size, not the
+ * canonical one after the delta has been applied.
+ *
+ * "hash" contains a path name hash which is used for sorting the
+ * delta list and also during delta searching. Once prepare_pack()
+ * returns it's no longer needed.
+ *
+ * source pack info
+ * ----------------
+ * The (in_pack, in_pack_offset) tuple contains the location of the
+ * object in the source pack. in_pack_header_size allows quickly
+ * skipping the header and going straight to the zlib stream.
+ *
+ * "type" and "in_pack_type" both describe object type. in_pack_type
+ * may contain a delta type, while type is always the canonical type.
+ *
+ * deltas
+ * ------
+ * Delta links (delta, delta_child and delta_sibling) are created to
+ * reflect that delta graph from the source pack then updated or added
+ * during delta searching phase when we find better deltas.
+ *
+ * delta_child and delta_sibling are last needed in
+ * compute_write_order(). "delta" and "delta_size" must remain valid
+ * at object writing phase in case the delta is not cached.
+ *
+ * If a delta is cached in memory and is compressed, delta_data points
+ * to the data and z_delta_size contains the compressed size. If it's
+ * uncompressed [1], z_delta_size must be zero. delta_size is always
+ * the uncompressed size and must be valid even if the delta is not
+ * cached.
+ *
+ * [1] during try_delta phase we don't bother with compressing because
+ * the delta could be quickly replaced with a better one.
+ */
 struct object_entry {
 	struct pack_idx_entry idx;
-	unsigned long size;	/* uncompressed size */
-	struct packed_git *in_pack;	/* already in pack */
-	off_t in_pack_offset;
-	struct object_entry *delta;	/* delta base object */
-	struct object_entry *delta_child; /* deltified objects who bases me */
-	struct object_entry *delta_sibling; /* other deltified objects who
-					     * uses the same base as me
-					     */
 	void *delta_data;	/* cached delta (uncompressed) */
-	unsigned long delta_size;	/* delta data size (uncompressed) */
-	unsigned long z_delta_size;	/* delta data size (compressed) */
-	enum object_type type;
-	enum object_type in_pack_type;	/* could be delta */
+	off_t in_pack_offset;
 	uint32_t hash;			/* name hint hash */
-	unsigned int in_pack_pos;
-	unsigned char in_pack_header_size;
+	unsigned size_:OE_SIZE_BITS;
+	unsigned size_valid:1;
+	uint32_t delta_idx;	/* delta base object */
+	uint32_t delta_child_idx; /* deltified objects who bases me */
+	uint32_t delta_sibling_idx; /* other deltified objects who
+				     * uses the same base as me
+				     */
+	unsigned delta_size_:OE_DELTA_SIZE_BITS; /* delta data size (uncompressed) */
+	unsigned delta_size_valid:1;
+	unsigned in_pack_idx:OE_IN_PACK_BITS;	/* already in pack */
+	unsigned z_delta_size:OE_Z_DELTA_BITS;
+	unsigned type_valid:1;
+	unsigned type_:TYPE_BITS;
+	unsigned no_try_delta:1;
+	unsigned in_pack_type:TYPE_BITS; /* could be delta */
 	unsigned preferred_base:1; /*
 				    * we do not pack this, but is available
 				    * to be used as the base object to delta
 				    * objects against.
 				    */
-	unsigned no_try_delta:1;
 	unsigned tagged:1; /* near the very tip of refs */
 	unsigned filled:1; /* assigned write-order */
+	unsigned dfs_state:OE_DFS_STATE_BITS;
+	unsigned char in_pack_header_size;
+	unsigned depth:OE_DEPTH_BITS;
 
 	/*
-	 * State flags for depth-first search used for analyzing delta cycles.
+	 * pahole results on 64-bit linux (gcc and clang)
 	 *
-	 * The depth is measured in delta-links to the base (so if A is a delta
-	 * against B, then A has a depth of 1, and B a depth of 0).
+	 *   size: 80, bit_padding: 20 bits, holes: 8 bits
+	 *
+	 * and on 32-bit (gcc)
+	 *
+	 *   size: 76, bit_padding: 20 bits, holes: 8 bits
 	 */
-	enum {
-		DFS_NONE = 0,
-		DFS_ACTIVE,
-		DFS_DONE
-	} dfs_state;
-	int depth;
 };
 
 struct packing_data {
@@ -48,8 +128,22 @@
 
 	int32_t *index;
 	uint32_t index_size;
+
+	unsigned int *in_pack_pos;
+
+	/*
+	 * Only one of these can be non-NULL and they have different
+	 * sizes. if in_pack_by_idx is allocated, oe_in_pack() returns
+	 * the pack of an object using in_pack_idx field. If not,
+	 * in_pack[] array is used the same way as in_pack_pos[]
+	 */
+	struct packed_git **in_pack_by_idx;
+	struct packed_git **in_pack;
+
+	uintmax_t oe_size_limit;
 };
 
+void prepare_packing_data(struct packing_data *pdata);
 struct object_entry *packlist_alloc(struct packing_data *pdata,
 				    const unsigned char *sha1,
 				    uint32_t index_pos);
@@ -78,4 +172,178 @@
 	return hash;
 }
 
+static inline enum object_type oe_type(const struct object_entry *e)
+{
+	return e->type_valid ? e->type_ : OBJ_BAD;
+}
+
+static inline void oe_set_type(struct object_entry *e,
+			       enum object_type type)
+{
+	if (type >= OBJ_ANY)
+		BUG("OBJ_ANY cannot be set in pack-objects code");
+
+	e->type_valid = type >= OBJ_NONE;
+	e->type_ = (unsigned)type;
+}
+
+static inline unsigned int oe_in_pack_pos(const struct packing_data *pack,
+					  const struct object_entry *e)
+{
+	return pack->in_pack_pos[e - pack->objects];
+}
+
+static inline void oe_set_in_pack_pos(const struct packing_data *pack,
+				      const struct object_entry *e,
+				      unsigned int pos)
+{
+	pack->in_pack_pos[e - pack->objects] = pos;
+}
+
+static inline struct packed_git *oe_in_pack(const struct packing_data *pack,
+					    const struct object_entry *e)
+{
+	if (pack->in_pack_by_idx)
+		return pack->in_pack_by_idx[e->in_pack_idx];
+	else
+		return pack->in_pack[e - pack->objects];
+}
+
+void oe_map_new_pack(struct packing_data *pack,
+		     struct packed_git *p);
+static inline void oe_set_in_pack(struct packing_data *pack,
+				  struct object_entry *e,
+				  struct packed_git *p)
+{
+	if (!p->index)
+		oe_map_new_pack(pack, p);
+	if (pack->in_pack_by_idx)
+		e->in_pack_idx = p->index;
+	else
+		pack->in_pack[e - pack->objects] = p;
+}
+
+static inline struct object_entry *oe_delta(
+		const struct packing_data *pack,
+		const struct object_entry *e)
+{
+	if (e->delta_idx)
+		return &pack->objects[e->delta_idx - 1];
+	return NULL;
+}
+
+static inline void oe_set_delta(struct packing_data *pack,
+				struct object_entry *e,
+				struct object_entry *delta)
+{
+	if (delta)
+		e->delta_idx = (delta - pack->objects) + 1;
+	else
+		e->delta_idx = 0;
+}
+
+static inline struct object_entry *oe_delta_child(
+		const struct packing_data *pack,
+		const struct object_entry *e)
+{
+	if (e->delta_child_idx)
+		return &pack->objects[e->delta_child_idx - 1];
+	return NULL;
+}
+
+static inline void oe_set_delta_child(struct packing_data *pack,
+				      struct object_entry *e,
+				      struct object_entry *delta)
+{
+	if (delta)
+		e->delta_child_idx = (delta - pack->objects) + 1;
+	else
+		e->delta_child_idx = 0;
+}
+
+static inline struct object_entry *oe_delta_sibling(
+		const struct packing_data *pack,
+		const struct object_entry *e)
+{
+	if (e->delta_sibling_idx)
+		return &pack->objects[e->delta_sibling_idx - 1];
+	return NULL;
+}
+
+static inline void oe_set_delta_sibling(struct packing_data *pack,
+					struct object_entry *e,
+					struct object_entry *delta)
+{
+	if (delta)
+		e->delta_sibling_idx = (delta - pack->objects) + 1;
+	else
+		e->delta_sibling_idx = 0;
+}
+
+unsigned long oe_get_size_slow(struct packing_data *pack,
+			       const struct object_entry *e);
+static inline unsigned long oe_size(struct packing_data *pack,
+				    const struct object_entry *e)
+{
+	if (e->size_valid)
+		return e->size_;
+
+	return oe_get_size_slow(pack, e);
+}
+
+static inline int oe_size_less_than(struct packing_data *pack,
+				    const struct object_entry *lhs,
+				    unsigned long rhs)
+{
+	if (lhs->size_valid)
+		return lhs->size_ < rhs;
+	if (rhs < pack->oe_size_limit) /* rhs < 2^x <= lhs ? */
+		return 0;
+	return oe_get_size_slow(pack, lhs) < rhs;
+}
+
+static inline int oe_size_greater_than(struct packing_data *pack,
+				       const struct object_entry *lhs,
+				       unsigned long rhs)
+{
+	if (lhs->size_valid)
+		return lhs->size_ > rhs;
+	if (rhs < pack->oe_size_limit) /* rhs < 2^x <= lhs ? */
+		return 1;
+	return oe_get_size_slow(pack, lhs) > rhs;
+}
+
+static inline void oe_set_size(struct packing_data *pack,
+			       struct object_entry *e,
+			       unsigned long size)
+{
+	if (size < pack->oe_size_limit) {
+		e->size_ = size;
+		e->size_valid = 1;
+	} else {
+		e->size_valid = 0;
+		if (oe_get_size_slow(pack, e) != size)
+			BUG("'size' is supposed to be the object size!");
+	}
+}
+
+static inline unsigned long oe_delta_size(struct packing_data *pack,
+					  const struct object_entry *e)
+{
+	if (e->delta_size_valid)
+		return e->delta_size_;
+	return oe_size(pack, e);
+}
+
+static inline void oe_set_delta_size(struct packing_data *pack,
+				     struct object_entry *e,
+				     unsigned long size)
+{
+	e->delta_size_ = size;
+	e->delta_size_valid = e->delta_size_ == size;
+	if (!e->delta_size_valid && size != oe_size(pack, e))
+		BUG("this can only happen in check_object() "
+		    "where delta size is the same as entry size");
+}
+
 #endif
diff --git a/pack-write.c b/pack-write.c
index d775c74..a9d46bc 100644
--- a/pack-write.c
+++ b/pack-write.c
@@ -170,8 +170,9 @@
 	}
 
 	hashwrite(f, sha1, the_hash_algo->rawsz);
-	hashclose(f, NULL, ((opts->flags & WRITE_IDX_VERIFY)
-			    ? CSUM_CLOSE : CSUM_FSYNC));
+	finalize_hashfile(f, NULL, CSUM_HASH_IN_STREAM | CSUM_CLOSE |
+				    ((opts->flags & WRITE_IDX_VERIFY)
+				    ? 0 : CSUM_FSYNC));
 	return index_name;
 }
 
diff --git a/packfile.c b/packfile.c
index 0bc67d0..1a714fb 100644
--- a/packfile.c
+++ b/packfile.c
@@ -84,6 +84,7 @@
 	uint32_t version, nr, i, *index;
 	int fd = git_open(path);
 	struct stat st;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 
 	if (fd < 0)
 		return -1;
@@ -92,7 +93,7 @@
 		return -1;
 	}
 	idx_size = xsize_t(st.st_size);
-	if (idx_size < 4 * 256 + 20 + 20) {
+	if (idx_size < 4 * 256 + hashsz + hashsz) {
 		close(fd);
 		return error("index file %s is too small", path);
 	}
@@ -129,11 +130,11 @@
 		/*
 		 * Total size:
 		 *  - 256 index entries 4 bytes each
-		 *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
-		 *  - 20-byte SHA1 of the packfile
-		 *  - 20-byte SHA1 file checksum
+		 *  - 24-byte entries * nr (object ID + 4-byte offset)
+		 *  - hash of the packfile
+		 *  - file checksum
 		 */
-		if (idx_size != 4*256 + nr * 24 + 20 + 20) {
+		if (idx_size != 4*256 + nr * (hashsz + 4) + hashsz + hashsz) {
 			munmap(idx_map, idx_size);
 			return error("wrong index v1 file size in %s", path);
 		}
@@ -142,16 +143,16 @@
 		 * Minimum size:
 		 *  - 8 bytes of header
 		 *  - 256 index entries 4 bytes each
-		 *  - 20-byte sha1 entry * nr
+		 *  - object ID entry * nr
 		 *  - 4-byte crc entry * nr
 		 *  - 4-byte offset entry * nr
-		 *  - 20-byte SHA1 of the packfile
-		 *  - 20-byte SHA1 file checksum
+		 *  - hash of the packfile
+		 *  - file checksum
 		 * And after the 4-byte offset table might be a
 		 * variable sized table containing 8-byte entries
 		 * for offsets larger than 2^31.
 		 */
-		unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
+		unsigned long min_size = 8 + 4*256 + nr*(hashsz + 4 + 4) + hashsz + hashsz;
 		unsigned long max_size = min_size;
 		if (nr)
 			max_size += (nr - 1)*8;
@@ -188,7 +189,7 @@
 		return 0;
 
 	if (!strip_suffix(p->pack_name, ".pack", &len))
-		die("BUG: pack_name does not end in .pack");
+		BUG("pack_name does not end in .pack");
 	idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
 	ret = check_packed_git_idx(idx_name, p);
 	free(idx_name);
@@ -304,7 +305,7 @@
 	}
 }
 
-static void close_pack(struct packed_git *p)
+void close_pack(struct packed_git *p)
 {
 	close_pack_windows(p);
 	close_pack_fd(p);
@@ -317,7 +318,7 @@
 
 	for (p = o->packed_git; p; p = p->next)
 		if (p->do_not_close)
-			die("BUG: want to close pack marked 'do-not-close'");
+			BUG("want to close pack marked 'do-not-close'");
 		else
 			close_pack(p);
 }
@@ -444,10 +445,11 @@
 {
 	struct stat st;
 	struct pack_header hdr;
-	unsigned char sha1[20];
-	unsigned char *idx_sha1;
+	unsigned char hash[GIT_MAX_RAWSZ];
+	unsigned char *idx_hash;
 	long fd_flag;
 	ssize_t read_result;
+	const unsigned hashsz = the_hash_algo->rawsz;
 
 	if (!p->index_data && open_pack_index(p))
 		return error("packfile %s index unavailable", p->pack_name);
@@ -507,15 +509,15 @@
 			     " while index indicates %"PRIu32" objects",
 			     p->pack_name, ntohl(hdr.hdr_entries),
 			     p->num_objects);
-	if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
+	if (lseek(p->pack_fd, p->pack_size - hashsz, SEEK_SET) == -1)
 		return error("end of packfile %s is unavailable", p->pack_name);
-	read_result = read_in_full(p->pack_fd, sha1, sizeof(sha1));
+	read_result = read_in_full(p->pack_fd, hash, hashsz);
 	if (read_result < 0)
 		return error_errno("error reading from %s", p->pack_name);
-	if (read_result != sizeof(sha1))
+	if (read_result != hashsz)
 		return error("packfile %s signature is unavailable", p->pack_name);
-	idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
-	if (hashcmp(sha1, idx_sha1))
+	idx_hash = ((unsigned char *)p->index_data) + p->index_size - hashsz * 2;
+	if (hashcmp(hash, idx_hash))
 		return error("packfile %s does not match index", p->pack_name);
 	return 0;
 }
@@ -530,7 +532,7 @@
 
 static int in_window(struct pack_window *win, off_t offset)
 {
-	/* We must promise at least 20 bytes (one hash) after the
+	/* We must promise at least one full hash after the
 	 * offset is available from this window, otherwise the offset
 	 * is not actually in this window and a different window (which
 	 * has that one hash excess) must be used.  This is to support
@@ -538,7 +540,7 @@
 	 */
 	off_t win_off = win->offset;
 	return win_off <= offset
-		&& (offset + 20) <= (win_off + win->len);
+		&& (offset + the_hash_algo->rawsz) <= (win_off + win->len);
 }
 
 unsigned char *use_pack(struct packed_git *p,
@@ -555,7 +557,7 @@
 	 */
 	if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
 		die("packfile %s cannot be accessed", p->pack_name);
-	if (offset > (p->pack_size - 20))
+	if (offset > (p->pack_size - the_hash_algo->rawsz))
 		die("offset beyond end of packfile (truncated pack?)");
 	if (offset < 0)
 		die(_("offset before end of packfile (broken .idx?)"));
@@ -675,7 +677,8 @@
 	p->pack_size = st.st_size;
 	p->pack_local = local;
 	p->mtime = st.st_mtime;
-	if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
+	if (path_len < the_hash_algo->hexsz ||
+	    get_sha1_hex(path + path_len - the_hash_algo->hexsz, p->sha1))
 		hashclr(p->sha1);
 	return p;
 }
@@ -1028,7 +1031,8 @@
 
 	for (p = the_repository->objects->packed_git; p; p = p->next)
 		for (i = 0; i < p->num_bad_objects; i++)
-			if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
+			if (!hashcmp(sha1,
+				     p->bad_object_sha1 + the_hash_algo->rawsz * i))
 				return p;
 	return NULL;
 }
@@ -1066,7 +1070,7 @@
 	} else if (type == OBJ_REF_DELTA) {
 		/* The base entry _must_ be in the same pack */
 		base_offset = find_pack_entry_one(base_info, p);
-		*curpos += 20;
+		*curpos += the_hash_algo->rawsz;
 	} else
 		die("I am totally screwed");
 	return base_offset;
@@ -1104,7 +1108,9 @@
 		return NULL;
 }
 
-static int retry_bad_packed_offset(struct packed_git *p, off_t obj_offset)
+static int retry_bad_packed_offset(struct repository *r,
+				   struct packed_git *p,
+				   off_t obj_offset)
 {
 	int type;
 	struct revindex_entry *revidx;
@@ -1114,7 +1120,7 @@
 		return OBJ_BAD;
 	nth_packed_object_oid(&oid, p, revidx->nr);
 	mark_bad_packed_object(p, oid.hash);
-	type = oid_object_info(&oid, NULL);
+	type = oid_object_info(r, &oid, NULL);
 	if (type <= OBJ_NONE)
 		return OBJ_BAD;
 	return type;
@@ -1122,7 +1128,8 @@
 
 #define POI_STACK_PREALLOC 64
 
-static enum object_type packed_to_object_type(struct packed_git *p,
+static enum object_type packed_to_object_type(struct repository *r,
+					      struct packed_git *p,
 					      off_t obj_offset,
 					      enum object_type type,
 					      struct pack_window **w_curs,
@@ -1153,7 +1160,7 @@
 		if (type <= OBJ_NONE) {
 			/* If getting the base itself fails, we first
 			 * retry the base, otherwise unwind */
-			type = retry_bad_packed_offset(p, base_offset);
+			type = retry_bad_packed_offset(r, p, base_offset);
 			if (type > OBJ_NONE)
 				goto out;
 			goto unwind;
@@ -1181,7 +1188,7 @@
 unwind:
 	while (poi_stack_nr) {
 		obj_offset = poi_stack[--poi_stack_nr];
-		type = retry_bad_packed_offset(p, obj_offset);
+		type = retry_bad_packed_offset(r, p, obj_offset);
 		if (type > OBJ_NONE)
 			goto out;
 	}
@@ -1268,14 +1275,15 @@
 	free(ent);
 }
 
-static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
-	unsigned long *base_size, enum object_type *type)
+static void *cache_or_unpack_entry(struct repository *r, struct packed_git *p,
+				   off_t base_offset, unsigned long *base_size,
+				   enum object_type *type)
 {
 	struct delta_base_cache_entry *ent;
 
 	ent = get_delta_base_cache_entry(p, base_offset);
 	if (!ent)
-		return unpack_entry(p, base_offset, type, base_size);
+		return unpack_entry(r, p, base_offset, type, base_size);
 
 	if (type)
 		*type = ent->type;
@@ -1329,8 +1337,8 @@
 	hashmap_add(&delta_base_cache, ent);
 }
 
-int packed_object_info(struct packed_git *p, off_t obj_offset,
-		       struct object_info *oi)
+int packed_object_info(struct repository *r, struct packed_git *p,
+		       off_t obj_offset, struct object_info *oi)
 {
 	struct pack_window *w_curs = NULL;
 	unsigned long size;
@@ -1342,7 +1350,7 @@
 	 * a "real" type later if the caller is interested.
 	 */
 	if (oi->contentp) {
-		*oi->contentp = cache_or_unpack_entry(p, obj_offset, oi->sizep,
+		*oi->contentp = cache_or_unpack_entry(r, p, obj_offset, oi->sizep,
 						      &type);
 		if (!*oi->contentp)
 			type = OBJ_BAD;
@@ -1376,8 +1384,8 @@
 
 	if (oi->typep || oi->type_name) {
 		enum object_type ptot;
-		ptot = packed_to_object_type(p, obj_offset, type, &w_curs,
-					     curpos);
+		ptot = packed_to_object_type(r, p, obj_offset,
+					     type, &w_curs, curpos);
 		if (oi->typep)
 			*oi->typep = ptot;
 		if (oi->type_name) {
@@ -1465,7 +1473,9 @@
 	unsigned long size;
 };
 
-static void *read_object(const struct object_id *oid, enum object_type *type,
+static void *read_object(struct repository *r,
+			 const struct object_id *oid,
+			 enum object_type *type,
 			 unsigned long *size)
 {
 	struct object_info oi = OBJECT_INFO_INIT;
@@ -1474,12 +1484,12 @@
 	oi.sizep = size;
 	oi.contentp = &content;
 
-	if (oid_object_info_extended(oid, &oi, 0) < 0)
+	if (oid_object_info_extended(r, oid, &oi, 0) < 0)
 		return NULL;
 	return content;
 }
 
-void *unpack_entry(struct packed_git *p, off_t obj_offset,
+void *unpack_entry(struct repository *r, struct packed_git *p, off_t obj_offset,
 		   enum object_type *final_type, unsigned long *final_size)
 {
 	struct pack_window *w_curs = NULL;
@@ -1561,7 +1571,7 @@
 	case OBJ_OFS_DELTA:
 	case OBJ_REF_DELTA:
 		if (data)
-			die("BUG: unpack_entry: left loop at a valid delta");
+			BUG("unpack_entry: left loop at a valid delta");
 		break;
 	case OBJ_COMMIT:
 	case OBJ_TREE:
@@ -1610,7 +1620,7 @@
 				      oid_to_hex(&base_oid), (uintmax_t)obj_offset,
 				      p->pack_name);
 				mark_bad_packed_object(p, base_oid.hash);
-				base = read_object(&base_oid, &type, &base_size);
+				base = read_object(r, &base_oid, &type, &base_size);
 				external_base = base;
 			}
 		}
@@ -1671,6 +1681,7 @@
 {
 	const unsigned char *index_fanout = p->index_data;
 	const unsigned char *index_lookup;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 	int index_lookup_width;
 
 	if (!index_fanout)
@@ -1678,10 +1689,10 @@
 
 	index_lookup = index_fanout + 4 * 256;
 	if (p->index_version == 1) {
-		index_lookup_width = 24;
+		index_lookup_width = hashsz + 4;
 		index_lookup += 4;
 	} else {
-		index_lookup_width = 20;
+		index_lookup_width = hashsz;
 		index_fanout += 8;
 		index_lookup += 8;
 	}
@@ -1694,6 +1705,7 @@
 					    uint32_t n)
 {
 	const unsigned char *index = p->index_data;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 	if (!index) {
 		if (open_pack_index(p))
 			return NULL;
@@ -1703,10 +1715,10 @@
 		return NULL;
 	index += 4 * 256;
 	if (p->index_version == 1) {
-		return index + 24 * n + 4;
+		return index + (hashsz + 4) * n + 4;
 	} else {
 		index += 8;
-		return index + 20 * n;
+		return index + hashsz * n;
 	}
 }
 
@@ -1738,12 +1750,13 @@
 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
 {
 	const unsigned char *index = p->index_data;
+	const unsigned int hashsz = the_hash_algo->rawsz;
 	index += 4 * 256;
 	if (p->index_version == 1) {
-		return ntohl(*((uint32_t *)(index + 24 * n)));
+		return ntohl(*((uint32_t *)(index + (hashsz + 4) * n)));
 	} else {
 		uint32_t off;
-		index += 8 + p->num_objects * (20 + 4);
+		index += 8 + p->num_objects * (hashsz + 4);
 		off = ntohl(*((uint32_t *)(index + 4 * n)));
 		if (!(off & 0x80000000))
 			return off;
@@ -1805,7 +1818,7 @@
 
 }
 
-static int fill_pack_entry(const unsigned char *sha1,
+static int fill_pack_entry(const struct object_id *oid,
 			   struct pack_entry *e,
 			   struct packed_git *p)
 {
@@ -1814,11 +1827,12 @@
 	if (p->num_bad_objects) {
 		unsigned i;
 		for (i = 0; i < p->num_bad_objects; i++)
-			if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
+			if (!hashcmp(oid->hash,
+				     p->bad_object_sha1 + the_hash_algo->rawsz * i))
 				return 0;
 	}
 
-	offset = find_pack_entry_one(sha1, p);
+	offset = find_pack_entry_one(oid->hash, p);
 	if (!offset)
 		return 0;
 
@@ -1833,11 +1847,10 @@
 		return 0;
 	e->offset = offset;
 	e->p = p;
-	hashcpy(e->sha1, sha1);
 	return 1;
 }
 
-int find_pack_entry(struct repository *r, const unsigned char *sha1, struct pack_entry *e)
+int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e)
 {
 	struct list_head *pos;
 
@@ -1847,7 +1860,7 @@
 
 	list_for_each(pos, &r->objects->packed_git_mru) {
 		struct packed_git *p = list_entry(pos, struct packed_git, mru);
-		if (fill_pack_entry(sha1, e, p)) {
+		if (fill_pack_entry(oid, e, p)) {
 			list_move(&p->mru, &r->objects->packed_git_mru);
 			return 1;
 		}
@@ -1855,10 +1868,10 @@
 	return 0;
 }
 
-int has_sha1_pack(const unsigned char *sha1)
+int has_object_pack(const struct object_id *oid)
 {
 	struct pack_entry e;
-	return find_pack_entry(the_repository, sha1, &e);
+	return find_pack_entry(the_repository, oid, &e);
 }
 
 int has_pack_index(const unsigned char *sha1)
@@ -1869,7 +1882,7 @@
 	return 1;
 }
 
-static int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn cb, void *data)
+int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn cb, void *data)
 {
 	uint32_t i;
 	int r = 0;
@@ -1944,7 +1957,7 @@
 		struct commit *commit = (struct commit *) obj;
 		struct commit_list *parents = commit->parents;
 
-		oidset_insert(set, &commit->tree->object.oid);
+		oidset_insert(set, get_commit_tree_oid(commit));
 		for (; parents; parents = parents->next)
 			oidset_insert(set, &parents->item->object.oid);
 	} else if (obj->type == OBJ_TAG) {
diff --git a/packfile.h b/packfile.h
index a92c0b2..e0a38ab 100644
--- a/packfile.h
+++ b/packfile.h
@@ -65,6 +65,7 @@
 
 extern unsigned char *use_pack(struct packed_git *, struct pack_window **, off_t, unsigned long *);
 extern void close_pack_windows(struct packed_git *);
+extern void close_pack(struct packed_git *);
 extern void close_all_packs(struct raw_object_store *o);
 extern void unuse_pack(struct pack_window **);
 extern void clear_delta_base_cache(void);
@@ -115,7 +116,7 @@
 extern off_t find_pack_entry_one(const unsigned char *sha1, struct packed_git *);
 
 extern int is_pack_valid(struct packed_git *);
-extern void *unpack_entry(struct packed_git *, off_t, enum object_type *, unsigned long *);
+extern void *unpack_entry(struct repository *r, struct packed_git *, off_t, enum object_type *, unsigned long *);
 extern unsigned long unpack_object_header_buffer(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep);
 extern unsigned long get_size_from_delta(struct packed_git *, struct pack_window **, off_t);
 extern int unpack_object_header(struct packed_git *, struct pack_window **, off_t *, unsigned long *);
@@ -125,7 +126,9 @@
 /* global flag to enable extra checks when accessing packed objects */
 extern int do_check_packed_object_crc;
 
-extern int packed_object_info(struct packed_git *pack, off_t offset, struct object_info *);
+extern int packed_object_info(struct repository *r,
+			      struct packed_git *pack,
+			      off_t offset, struct object_info *);
 
 extern void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1);
 extern const struct packed_git *has_packed_and_bad(const unsigned char *sha1);
@@ -134,9 +137,9 @@
  * Iff a pack file in the given repository contains the object named by sha1,
  * return true and store its location to e.
  */
-extern int find_pack_entry(struct repository *r, const unsigned char *sha1, struct pack_entry *e);
+extern int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e);
 
-extern int has_sha1_pack(const unsigned char *sha1);
+extern int has_object_pack(const struct object_id *oid);
 
 extern int has_pack_index(const unsigned char *sha1);
 
@@ -154,6 +157,7 @@
 				  struct packed_git *pack,
 				  uint32_t pos,
 				  void *data);
+extern int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn, void *data);
 extern int for_each_packed_object(each_packed_object_fn, void *, unsigned flags);
 
 /*
diff --git a/pager.c b/pager.c
index 92b23e6..a768797 100644
--- a/pager.c
+++ b/pager.c
@@ -2,6 +2,7 @@
 #include "config.h"
 #include "run-command.h"
 #include "sigchain.h"
+#include "alias.h"
 
 #ifndef DEFAULT_PAGER
 #define DEFAULT_PAGER "less"
@@ -109,10 +110,15 @@
 		return;
 
 	/*
-	 * force computing the width of the terminal before we redirect
-	 * the standard output to the pager.
+	 * After we redirect standard output, we won't be able to use an ioctl
+	 * to get the terminal size. Let's grab it now, and then set $COLUMNS
+	 * to communicate it to any sub-processes.
 	 */
-	(void) term_columns();
+	{
+		char buf[64];
+		xsnprintf(buf, sizeof(buf), "%d", term_columns());
+		setenv("COLUMNS", buf, 0);
+	}
 
 	setenv("GIT_PAGER_IN_USE", "true", 1);
 
diff --git a/parse-options-cb.c b/parse-options-cb.c
index c6679cb..0f9f311 100644
--- a/parse-options-cb.c
+++ b/parse-options-cb.c
@@ -38,7 +38,11 @@
 int parse_opt_expiry_date_cb(const struct option *opt, const char *arg,
 			     int unset)
 {
-	return parse_expiry_date(arg, (timestamp_t *)opt->value);
+	if (unset)
+		arg = "never";
+	if (parse_expiry_date(arg, (timestamp_t *)opt->value))
+		die(_("malformed expiration date '%s'"), arg);
+	return 0;
 }
 
 int parse_opt_color_flag_cb(const struct option *opt, const char *arg,
diff --git a/path.c b/path.c
index 3308b7b..7f109f6 100644
--- a/path.c
+++ b/path.c
@@ -1306,7 +1306,7 @@
 
 int is_ntfs_dotgit(const char *name)
 {
-	int len;
+	size_t len;
 
 	for (len = 0; ; len++)
 		if (!name[len] || name[len] == '\\' || is_dir_sep(name[len])) {
@@ -1323,6 +1323,90 @@
 		}
 }
 
+static int is_ntfs_dot_generic(const char *name,
+			       const char *dotgit_name,
+			       size_t len,
+			       const char *dotgit_ntfs_shortname_prefix)
+{
+	int saw_tilde;
+	size_t i;
+
+	if ((name[0] == '.' && !strncasecmp(name + 1, dotgit_name, len))) {
+		i = len + 1;
+only_spaces_and_periods:
+		for (;;) {
+			char c = name[i++];
+			if (!c)
+				return 1;
+			if (c != ' ' && c != '.')
+				return 0;
+		}
+	}
+
+	/*
+	 * Is it a regular NTFS short name, i.e. shortened to 6 characters,
+	 * followed by ~1, ... ~4?
+	 */
+	if (!strncasecmp(name, dotgit_name, 6) && name[6] == '~' &&
+	    name[7] >= '1' && name[7] <= '4') {
+		i = 8;
+		goto only_spaces_and_periods;
+	}
+
+	/*
+	 * Is it a fall-back NTFS short name (for details, see
+	 * https://en.wikipedia.org/wiki/8.3_filename?
+	 */
+	for (i = 0, saw_tilde = 0; i < 8; i++)
+		if (name[i] == '\0')
+			return 0;
+		else if (saw_tilde) {
+			if (name[i] < '0' || name[i] > '9')
+				return 0;
+		} else if (name[i] == '~') {
+			if (name[++i] < '1' || name[i] > '9')
+				return 0;
+			saw_tilde = 1;
+		} else if (i >= 6)
+			return 0;
+		else if (name[i] < 0) {
+			/*
+			 * We know our needles contain only ASCII, so we clamp
+			 * here to make the results of tolower() sane.
+			 */
+			return 0;
+		} else if (tolower(name[i]) != dotgit_ntfs_shortname_prefix[i])
+			return 0;
+
+	goto only_spaces_and_periods;
+}
+
+/*
+ * Inline helper to make sure compiler resolves strlen() on literals at
+ * compile time.
+ */
+static inline int is_ntfs_dot_str(const char *name, const char *dotgit_name,
+				  const char *dotgit_ntfs_shortname_prefix)
+{
+	return is_ntfs_dot_generic(name, dotgit_name, strlen(dotgit_name),
+				   dotgit_ntfs_shortname_prefix);
+}
+
+int is_ntfs_dotgitmodules(const char *name)
+{
+	return is_ntfs_dot_str(name, "gitmodules", "gi7eba");
+}
+
+int is_ntfs_dotgitignore(const char *name)
+{
+	return is_ntfs_dot_str(name, "gitignore", "gi250a");
+}
+
+int is_ntfs_dotgitattributes(const char *name)
+{
+	return is_ntfs_dot_str(name, "gitattributes", "gi7d29");
+}
+
 int looks_like_command_line_option(const char *str)
 {
 	return str && str[0] == '-';
diff --git a/pathspec.c b/pathspec.c
index 82eb39c..27cd606 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -198,7 +198,7 @@
 	}
 
 	if (item->attr_check->nr != item->attr_match_nr)
-		die("BUG: should have same number of entries");
+		BUG("should have same number of entries");
 
 	string_list_clear(&list, 0);
 }
@@ -422,7 +422,7 @@
 
 	if (pathspec_prefix >= 0 &&
 	    (prefixlen || (prefix && *prefix)))
-		die("BUG: 'prefix' magic is supposed to be used at worktree's root");
+		BUG("'prefix' magic is supposed to be used at worktree's root");
 
 	if ((magic & PATHSPEC_LITERAL) && (magic & PATHSPEC_GLOB))
 		die(_("%s: 'literal' and 'glob' are incompatible"), elt);
@@ -486,7 +486,7 @@
 	/* sanity checks, pathspec matchers assume these are sane */
 	if (item->nowildcard_len > item->len ||
 	    item->prefix         > item->len) {
-		die ("BUG: error initializing pathspec_item");
+		BUG("error initializing pathspec_item");
 	}
 }
 
@@ -545,7 +545,7 @@
 
 	if ((flags & PATHSPEC_PREFER_CWD) &&
 	    (flags & PATHSPEC_PREFER_FULL))
-		die("BUG: PATHSPEC_PREFER_CWD and PATHSPEC_PREFER_FULL are incompatible");
+		BUG("PATHSPEC_PREFER_CWD and PATHSPEC_PREFER_FULL are incompatible");
 
 	/* No arguments with prefix -> prefix pathspec */
 	if (!entry) {
@@ -553,7 +553,7 @@
 			return;
 
 		if (!(flags & PATHSPEC_PREFER_CWD))
-			die("BUG: PATHSPEC_PREFER_CWD requires arguments");
+			BUG("PATHSPEC_PREFER_CWD requires arguments");
 
 		pathspec->items = item = xcalloc(1, sizeof(*item));
 		item->match = xstrdup(prefix);
@@ -609,7 +609,7 @@
 
 	if (pathspec->magic & PATHSPEC_MAXDEPTH) {
 		if (flags & PATHSPEC_KEEP_ORDER)
-			die("BUG: PATHSPEC_MAXDEPTH_VALID and PATHSPEC_KEEP_ORDER are incompatible");
+			BUG("PATHSPEC_MAXDEPTH_VALID and PATHSPEC_KEEP_ORDER are incompatible");
 		QSORT(pathspec->items, pathspec->nr, pathspec_item_cmp);
 	}
 }
diff --git a/perl/Git.pm b/perl/Git.pm
index 16ebcc6..d856930 100644
--- a/perl/Git.pm
+++ b/perl/Git.pm
@@ -554,7 +554,7 @@
 	my ($fh, $rs) = @_;
 	local $/ = $rs;
 	my $rec = <$fh>;
-	chomp $rec if defined $rs;
+	chomp $rec if defined $rec;
 	$rec;
 }
 
diff --git a/perl/Git/I18N.pm b/perl/Git/I18N.pm
index dba96ff..bfb4fb6 100644
--- a/perl/Git/I18N.pm
+++ b/perl/Git/I18N.pm
@@ -18,7 +18,7 @@
 
 sub __bootstrap_locale_messages {
 	our $TEXTDOMAIN = 'git';
-	our $TEXTDOMAINDIR = $ENV{GIT_TEXTDOMAINDIR} || '@@LOCALEDIR@@';
+	our $TEXTDOMAINDIR ||= $ENV{GIT_TEXTDOMAINDIR} || '@@LOCALEDIR@@';
 
 	require POSIX;
 	POSIX->import(qw(setlocale));
diff --git a/perl/header_templates/fixed_prefix.template.pl b/perl/header_templates/fixed_prefix.template.pl
new file mode 100644
index 0000000..857b439
--- /dev/null
+++ b/perl/header_templates/fixed_prefix.template.pl
@@ -0,0 +1 @@
+use lib (split(/@@PATHSEP@@/, $ENV{GITPERLLIB} || '@@INSTLIBDIR@@'));
diff --git a/perl/header_templates/runtime_prefix.template.pl b/perl/header_templates/runtime_prefix.template.pl
new file mode 100644
index 0000000..9d28b3d
--- /dev/null
+++ b/perl/header_templates/runtime_prefix.template.pl
@@ -0,0 +1,42 @@
+# BEGIN RUNTIME_PREFIX generated code.
+#
+# This finds our Git::* libraries relative to the script's runtime path.
+sub __git_system_path {
+	my ($relpath) = @_;
+	my $gitexecdir_relative = '@@GITEXECDIR_REL@@';
+
+	# GIT_EXEC_PATH is supplied by `git` or the test suite.
+	my $exec_path;
+	if (exists $ENV{GIT_EXEC_PATH}) {
+		$exec_path = $ENV{GIT_EXEC_PATH};
+	} else {
+		# This can happen if this script is being directly invoked instead of run
+		# by "git".
+		require FindBin;
+		$exec_path = $FindBin::Bin;
+	}
+
+	# Trim off the relative gitexecdir path to get the system path.
+	(my $prefix = $exec_path) =~ s/\Q$gitexecdir_relative\E$//;
+
+	require File::Spec;
+	return File::Spec->catdir($prefix, $relpath);
+}
+
+BEGIN {
+	use lib split /@@PATHSEP@@/,
+	(
+		$ENV{GITPERLLIB} ||
+		do {
+			my $perllibdir = __git_system_path('@@PERLLIBDIR_REL@@');
+			(-e $perllibdir) || die("Invalid system path ($relpath): $path");
+			$perllibdir;
+		}
+	);
+
+	# Export the system locale directory to the I18N module. The locale directory
+	# is only installed if NO_GETTEXT is set.
+	$Git::I18N::TEXTDOMAINDIR = __git_system_path('@@LOCALEDIR_REL@@');
+}
+
+# END RUNTIME_PREFIX generated code.
diff --git a/pkt-line.c b/pkt-line.c
index 2827ca7..a593c08 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -91,6 +91,12 @@
 	write_or_die(fd, "0000", 4);
 }
 
+void packet_delim(int fd)
+{
+	packet_trace("0001", 4, 1);
+	write_or_die(fd, "0001", 4);
+}
+
 int packet_flush_gently(int fd)
 {
 	packet_trace("0000", 4, 1);
@@ -105,6 +111,12 @@
 	strbuf_add(buf, "0000", 4);
 }
 
+void packet_buf_delim(struct strbuf *buf)
+{
+	packet_trace("0001", 4, 1);
+	strbuf_add(buf, "0001", 4);
+}
+
 static void set_packet_header(char *buf, const int size)
 {
 	static char hexchar[] = "0123456789abcdef";
@@ -203,6 +215,22 @@
 	va_end(args);
 }
 
+void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len)
+{
+	size_t orig_len, n;
+
+	orig_len = buf->len;
+	strbuf_addstr(buf, "0000");
+	strbuf_add(buf, data, len);
+	n = buf->len - orig_len;
+
+	if (n > LARGE_PACKET_MAX)
+		die("protocol error: impossibly long line");
+
+	set_packet_header(&buf->buf[orig_len], n);
+	packet_trace(data, len, 1);
+}
+
 int write_packetized_from_fd(int fd_in, int fd_out)
 {
 	static char buf[LARGE_PACKET_DATA_MAX];
@@ -249,7 +277,7 @@
 	ssize_t ret;
 
 	if (fd >= 0 && src_buf && *src_buf)
-		die("BUG: multiple sources given to packet_read");
+		BUG("multiple sources given to packet_read");
 
 	/* Read up to "size" bytes from our source, whatever it is. */
 	if (src_buf && *src_buf) {
@@ -280,28 +308,43 @@
 	return (val < 0) ? val : (val << 8) | hex2chr(linelen + 2);
 }
 
-int packet_read(int fd, char **src_buf, size_t *src_len,
-		char *buffer, unsigned size, int options)
+enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
+						size_t *src_len, char *buffer,
+						unsigned size, int *pktlen,
+						int options)
 {
-	int len, ret;
+	int len;
 	char linelen[4];
 
-	ret = get_packet_data(fd, src_buf, src_len, linelen, 4, options);
-	if (ret < 0)
-		return ret;
-	len = packet_length(linelen);
-	if (len < 0)
-		die("protocol error: bad line length character: %.4s", linelen);
-	if (!len) {
-		packet_trace("0000", 4, 0);
-		return 0;
+	if (get_packet_data(fd, src_buffer, src_len, linelen, 4, options) < 0) {
+		*pktlen = -1;
+		return PACKET_READ_EOF;
 	}
-	len -= 4;
-	if (len >= size)
+
+	len = packet_length(linelen);
+
+	if (len < 0) {
+		die("protocol error: bad line length character: %.4s", linelen);
+	} else if (!len) {
+		packet_trace("0000", 4, 0);
+		*pktlen = 0;
+		return PACKET_READ_FLUSH;
+	} else if (len == 1) {
+		packet_trace("0001", 4, 0);
+		*pktlen = 0;
+		return PACKET_READ_DELIM;
+	} else if (len < 4) {
 		die("protocol error: bad line length %d", len);
-	ret = get_packet_data(fd, src_buf, src_len, buffer, len, options);
-	if (ret < 0)
-		return ret;
+	}
+
+	len -= 4;
+	if ((unsigned)len >= size)
+		die("protocol error: bad line length %d", len);
+
+	if (get_packet_data(fd, src_buffer, src_len, buffer, len, options) < 0) {
+		*pktlen = -1;
+		return PACKET_READ_EOF;
+	}
 
 	if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 	    len && buffer[len-1] == '\n')
@@ -309,7 +352,19 @@
 
 	buffer[len] = 0;
 	packet_trace(buffer, len, 0);
-	return len;
+	*pktlen = len;
+	return PACKET_READ_NORMAL;
+}
+
+int packet_read(int fd, char **src_buffer, size_t *src_len,
+		char *buffer, unsigned size, int options)
+{
+	int pktlen = -1;
+
+	packet_read_with_status(fd, src_buffer, src_len, buffer, size,
+				&pktlen, options);
+
+	return pktlen;
 }
 
 static char *packet_read_line_generic(int fd,
@@ -377,3 +432,53 @@
 	}
 	return sb_out->len - orig_len;
 }
+
+/* Packet Reader Functions */
+void packet_reader_init(struct packet_reader *reader, int fd,
+			char *src_buffer, size_t src_len,
+			int options)
+{
+	memset(reader, 0, sizeof(*reader));
+
+	reader->fd = fd;
+	reader->src_buffer = src_buffer;
+	reader->src_len = src_len;
+	reader->buffer = packet_buffer;
+	reader->buffer_size = sizeof(packet_buffer);
+	reader->options = options;
+}
+
+enum packet_read_status packet_reader_read(struct packet_reader *reader)
+{
+	if (reader->line_peeked) {
+		reader->line_peeked = 0;
+		return reader->status;
+	}
+
+	reader->status = packet_read_with_status(reader->fd,
+						 &reader->src_buffer,
+						 &reader->src_len,
+						 reader->buffer,
+						 reader->buffer_size,
+						 &reader->pktlen,
+						 reader->options);
+
+	if (reader->status == PACKET_READ_NORMAL)
+		reader->line = reader->buffer;
+	else
+		reader->line = NULL;
+
+	return reader->status;
+}
+
+enum packet_read_status packet_reader_peek(struct packet_reader *reader)
+{
+	/* Only allow peeking a single line */
+	if (reader->line_peeked)
+		return reader->status;
+
+	/* Peek a line by reading it and setting peeked flag */
+	packet_reader_read(reader);
+	reader->line_peeked = 1;
+	return reader->status;
+}
diff --git a/pkt-line.h b/pkt-line.h
index 3dad583..5b28d43 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -20,10 +20,13 @@
  * side can't, we stay with pure read/write interfaces.
  */
 void packet_flush(int fd);
+void packet_delim(int fd);
 void packet_write_fmt(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
 void packet_buf_flush(struct strbuf *buf);
+void packet_buf_delim(struct strbuf *buf);
 void packet_write(int fd_out, const char *buf, size_t size);
 void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
+void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len);
 int packet_flush_gently(int fd);
 int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
 int write_packetized_from_fd(int fd_in, int fd_out);
@@ -66,6 +69,23 @@
 		*buffer, unsigned size, int options);
 
 /*
+ * Read a packetized line into a buffer like the 'packet_read()' function but
+ * returns an 'enum packet_read_status' which indicates the status of the read.
+ * The number of bytes read will be assigined to *pktlen if the status of the
+ * read was 'PACKET_READ_NORMAL'.
+ */
+enum packet_read_status {
+	PACKET_READ_EOF,
+	PACKET_READ_NORMAL,
+	PACKET_READ_FLUSH,
+	PACKET_READ_DELIM,
+};
+enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
+						size_t *src_len, char *buffer,
+						unsigned size, int *pktlen,
+						int options);
+
+/*
  * Convenience wrapper for packet_read that is not gentle, and sets the
  * CHOMP_NEWLINE option. The return value is NULL for a flush packet,
  * and otherwise points to a static buffer (that may be overwritten by
@@ -96,6 +116,64 @@
  */
 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out);
 
+struct packet_reader {
+	/* source file descriptor */
+	int fd;
+
+	/* source buffer and its size */
+	char *src_buffer;
+	size_t src_len;
+
+	/* buffer that pkt-lines are read into and its size */
+	char *buffer;
+	unsigned buffer_size;
+
+	/* options to be used during reads */
+	int options;
+
+	/* status of the last read */
+	enum packet_read_status status;
+
+	/* length of data read during the last read */
+	int pktlen;
+
+	/* the last line read */
+	const char *line;
+
+	/* indicates if a line has been peeked */
+	int line_peeked;
+};
+
+/*
+ * Initialize a 'struct packet_reader' object which is an
+ * abstraction around the 'packet_read_with_status()' function.
+ */
+extern void packet_reader_init(struct packet_reader *reader, int fd,
+			       char *src_buffer, size_t src_len,
+			       int options);
+
+/*
+ * Perform a packet read and return the status of the read.
+ * The values of 'pktlen' and 'line' are updated based on the status of the
+ * read as follows:
+ *
+ * PACKET_READ_ERROR: 'pktlen' is set to '-1' and 'line' is set to NULL
+ * PACKET_READ_NORMAL: 'pktlen' is set to the number of bytes read
+ *		       'line' is set to point at the read line
+ * PACKET_READ_FLUSH: 'pktlen' is set to '0' and 'line' is set to NULL
+ */
+extern enum packet_read_status packet_reader_read(struct packet_reader *reader);
+
+/*
+ * Peek the next packet line without consuming it and return the status.
+ * The next call to 'packet_reader_read()' will perform a read of the same line
+ * that was peeked, consuming the line.
+ *
+ * Peeking multiple times without calling 'packet_reader_read()' will return
+ * the same result.
+ */
+extern enum packet_read_status packet_reader_peek(struct packet_reader *reader);
+
 #define DEFAULT_PACKET_MAX 1000
 #define LARGE_PACKET_MAX 65520
 #define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4)
diff --git a/pretty.c b/pretty.c
index 34fe891..703fa6f 100644
--- a/pretty.c
+++ b/pretty.c
@@ -1161,10 +1161,11 @@
 		strbuf_addstr(sb, diff_get_color(c->auto_color, DIFF_RESET));
 		return 1;
 	case 'T':		/* tree hash */
-		strbuf_addstr(sb, oid_to_hex(&commit->tree->object.oid));
+		strbuf_addstr(sb, oid_to_hex(get_commit_tree_oid(commit)));
 		return 1;
 	case 't':		/* abbreviated tree hash */
-		strbuf_add_unique_abbrev(sb, &commit->tree->object.oid,
+		strbuf_add_unique_abbrev(sb,
+					 get_commit_tree_oid(commit),
 					 c->pretty_ctx->abbrev);
 		return 1;
 	case 'P':		/* parent hashes */
diff --git a/prio-queue.c b/prio-queue.c
index 126d096..a078451 100644
--- a/prio-queue.c
+++ b/prio-queue.c
@@ -20,7 +20,7 @@
 	int i, j;
 
 	if (queue->compare != NULL)
-		die("BUG: prio_queue_reverse() on non-LIFO queue");
+		BUG("prio_queue_reverse() on non-LIFO queue");
 	for (i = 0; i < (j = (queue->nr - 1) - i); i++)
 		swap(queue, i, j);
 }
diff --git a/protocol.c b/protocol.c
index 43012b7..5e63678 100644
--- a/protocol.c
+++ b/protocol.c
@@ -8,6 +8,8 @@
 		return protocol_v0;
 	else if (!strcmp(value, "1"))
 		return protocol_v1;
+	else if (!strcmp(value, "2"))
+		return protocol_v2;
 	else
 		return protocol_unknown_version;
 }
diff --git a/protocol.h b/protocol.h
index 1b2bc94..2ad35e4 100644
--- a/protocol.h
+++ b/protocol.h
@@ -5,6 +5,7 @@
 	protocol_unknown_version = -1,
 	protocol_v0 = 0,
 	protocol_v1 = 1,
+	protocol_v2 = 2,
 };
 
 /*
diff --git a/reachable.c b/reachable.c
index a6ea33a..ffb976c 100644
--- a/reachable.c
+++ b/reachable.c
@@ -78,7 +78,7 @@
 	 * later processing, and the revision machinery expects
 	 * commits and tags to have been parsed.
 	 */
-	type = oid_object_info(oid, NULL);
+	type = oid_object_info(the_repository, oid, NULL);
 	if (type < 0)
 		die("unable to get object info for %s", oid_to_hex(oid));
 
diff --git a/read-cache.c b/read-cache.c
index 10f1c6b..3725882 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -752,7 +752,7 @@
 	int size, len;
 	struct cache_entry *ce, *ret;
 
-	if (!verify_path(path)) {
+	if (!verify_path(path, mode)) {
 		error("Invalid path '%s'", path);
 		return NULL;
 	}
@@ -817,7 +817,7 @@
  * Also, we don't want double slashes or slashes at the
  * end that can make pathnames ambiguous.
  */
-static int verify_dotfile(const char *rest)
+static int verify_dotfile(const char *rest, unsigned mode)
 {
 	/*
 	 * The first character was '.', but that
@@ -831,8 +831,13 @@
 
 	switch (*rest) {
 	/*
-	 * ".git" followed by  NUL or slash is bad. This
-	 * shares the path end test with the ".." case.
+	 * ".git" followed by NUL or slash is bad. Note that we match
+	 * case-insensitively here, even if ignore_case is not set.
+	 * This outlaws ".GIT" everywhere out of an abundance of caution,
+	 * since there's really no good reason to allow it.
+	 *
+	 * Once we've seen ".git", we can also find ".gitmodules", etc (also
+	 * case-insensitively).
 	 */
 	case 'g':
 	case 'G':
@@ -840,8 +845,15 @@
 			break;
 		if (rest[2] != 't' && rest[2] != 'T')
 			break;
-		rest += 2;
-	/* fallthrough */
+		if (rest[3] == '\0' || is_dir_sep(rest[3]))
+			return 0;
+		if (S_ISLNK(mode)) {
+			rest += 3;
+			if (skip_iprefix(rest, "modules", &rest) &&
+			    (*rest == '\0' || is_dir_sep(*rest)))
+				return 0;
+		}
+		break;
 	case '.':
 		if (rest[1] == '\0' || is_dir_sep(rest[1]))
 			return 0;
@@ -849,7 +861,7 @@
 	return 1;
 }
 
-int verify_path(const char *path)
+int verify_path(const char *path, unsigned mode)
 {
 	char c;
 
@@ -862,12 +874,25 @@
 			return 1;
 		if (is_dir_sep(c)) {
 inside:
-			if (protect_hfs && is_hfs_dotgit(path))
-				return 0;
-			if (protect_ntfs && is_ntfs_dotgit(path))
-				return 0;
+			if (protect_hfs) {
+				if (is_hfs_dotgit(path))
+					return 0;
+				if (S_ISLNK(mode)) {
+					if (is_hfs_dotgitmodules(path))
+						return 0;
+				}
+			}
+			if (protect_ntfs) {
+				if (is_ntfs_dotgit(path))
+					return 0;
+				if (S_ISLNK(mode)) {
+					if (is_ntfs_dotgitmodules(path))
+						return 0;
+				}
+			}
+
 			c = *path++;
-			if ((c == '.' && !verify_dotfile(path)) ||
+			if ((c == '.' && !verify_dotfile(path, mode)) ||
 			    is_dir_sep(c) || c == '\0')
 				return 0;
 		}
@@ -1184,7 +1209,7 @@
 
 	if (!ok_to_add)
 		return -1;
-	if (!verify_path(ce->name))
+	if (!verify_path(ce->name, ce->ce_mode))
 		return error("Invalid path '%s'", ce->name);
 
 	if (!skip_df_check &&
@@ -1806,7 +1831,7 @@
 	if (verify_hdr(hdr, mmap_size) < 0)
 		goto unmap;
 
-	hashcpy(istate->sha1, (const unsigned char *)hdr + mmap_size - the_hash_algo->rawsz);
+	hashcpy(istate->oid.hash, (const unsigned char *)hdr + mmap_size - the_hash_algo->rawsz);
 	istate->version = ntohl(hdr->hdr_version);
 	istate->cache_nr = ntohl(hdr->hdr_entries);
 	istate->cache_alloc = alloc_nr(istate->cache_nr);
@@ -1878,7 +1903,7 @@
 	uint64_t start = getnanotime();
 	struct split_index *split_index;
 	int ret;
-	char *base_sha1_hex;
+	char *base_oid_hex;
 	char *base_path;
 
 	/* istate->initialized covers both .git/index and .git/sharedindex.xxx */
@@ -1889,7 +1914,7 @@
 	trace_performance_since(start, "read cache %s", path);
 
 	split_index = istate->split_index;
-	if (!split_index || is_null_sha1(split_index->base_sha1)) {
+	if (!split_index || is_null_oid(&split_index->base_oid)) {
 		post_read_index_from(istate);
 		return ret;
 	}
@@ -1899,13 +1924,13 @@
 	else
 		split_index->base = xcalloc(1, sizeof(*split_index->base));
 
-	base_sha1_hex = sha1_to_hex(split_index->base_sha1);
-	base_path = xstrfmt("%s/sharedindex.%s", gitdir, base_sha1_hex);
+	base_oid_hex = oid_to_hex(&split_index->base_oid);
+	base_path = xstrfmt("%s/sharedindex.%s", gitdir, base_oid_hex);
 	ret = do_read_index(split_index->base, base_path, 1);
-	if (hashcmp(split_index->base_sha1, split_index->base->sha1))
+	if (oidcmp(&split_index->base_oid, &split_index->base->oid))
 		die("broken index, expect %s in %s, got %s",
-		    base_sha1_hex, base_path,
-		    sha1_to_hex(split_index->base->sha1));
+		    base_oid_hex, base_path,
+		    oid_to_hex(&split_index->base->oid));
 
 	freshen_shared_index(base_path, 0);
 	merge_base_index(istate);
@@ -2194,7 +2219,7 @@
 	if (n != the_hash_algo->rawsz)
 		goto out;
 
-	if (hashcmp(istate->sha1, hash))
+	if (hashcmp(istate->oid.hash, hash))
 		goto out;
 
 	close(fd);
@@ -2268,7 +2293,7 @@
 
 	if (!istate->version) {
 		istate->version = get_index_format_default();
-		if (getenv("GIT_TEST_SPLIT_INDEX"))
+		if (git_env_bool("GIT_TEST_SPLIT_INDEX", 0))
 			init_split_index(istate);
 	}
 
@@ -2373,7 +2398,7 @@
 			return -1;
 	}
 
-	if (ce_flush(&c, newfd, istate->sha1))
+	if (ce_flush(&c, newfd, istate->oid.hash))
 		return -1;
 	if (close_tempfile_gently(tempfile)) {
 		error(_("could not close '%s'"), tempfile->filename.buf);
@@ -2497,10 +2522,10 @@
 		return ret;
 	}
 	ret = rename_tempfile(temp,
-			      git_path("sharedindex.%s", sha1_to_hex(si->base->sha1)));
+			      git_path("sharedindex.%s", oid_to_hex(&si->base->oid)));
 	if (!ret) {
-		hashcpy(si->base_sha1, si->base->sha1);
-		clean_shared_index_files(sha1_to_hex(si->base->sha1));
+		oidcpy(&si->base_oid, &si->base->oid);
+		clean_shared_index_files(oid_to_hex(&si->base->oid));
 	}
 
 	return ret;
@@ -2554,13 +2579,13 @@
 	if (!si || alternate_index_output ||
 	    (istate->cache_changed & ~EXTMASK)) {
 		if (si)
-			hashclr(si->base_sha1);
+			oidclr(&si->base_oid);
 		ret = do_write_locked_index(istate, lock, flags);
 		goto out;
 	}
 
-	if (getenv("GIT_TEST_SPLIT_INDEX")) {
-		int v = si->base_sha1[0];
+	if (git_env_bool("GIT_TEST_SPLIT_INDEX", 0)) {
+		int v = si->base_oid.hash[0];
 		if ((v & 15) < 6)
 			istate->cache_changed |= SPLIT_INDEX_ORDERED;
 	}
@@ -2575,7 +2600,7 @@
 
 		temp = mks_tempfile(git_path("sharedindex_XXXXXX"));
 		if (!temp) {
-			hashclr(si->base_sha1);
+			oidclr(&si->base_oid);
 			ret = do_write_locked_index(istate, lock, flags);
 			goto out;
 		}
@@ -2595,7 +2620,7 @@
 	/* Freshen the shared index only if the split-index was written */
 	if (!ret && !new_shared_index) {
 		const char *shared_index = git_path("sharedindex.%s",
-						    sha1_to_hex(si->base_sha1));
+						    oid_to_hex(&si->base_oid));
 		freshen_shared_index(shared_index, 1);
 	}
 
diff --git a/ref-filter.c b/ref-filter.c
index ac82f9f..01c1a82 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -101,22 +101,38 @@
 } *used_atom;
 static int used_atom_cnt, need_tagged, need_symref;
 
-static void color_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *color_value)
+/*
+ * Expand string, append it to strbuf *sb, then return error code ret.
+ * Allow to save few lines of code.
+ */
+static int strbuf_addf_ret(struct strbuf *sb, int ret, const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	strbuf_vaddf(sb, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+static int color_atom_parser(const struct ref_format *format, struct used_atom *atom,
+			     const char *color_value, struct strbuf *err)
 {
 	if (!color_value)
-		die(_("expected format: %%(color:<color>)"));
+		return strbuf_addf_ret(err, -1, _("expected format: %%(color:<color>)"));
 	if (color_parse(color_value, atom->u.color) < 0)
-		die(_("unrecognized color: %%(color:%s)"), color_value);
+		return strbuf_addf_ret(err, -1, _("unrecognized color: %%(color:%s)"),
+				       color_value);
 	/*
 	 * We check this after we've parsed the color, which lets us complain
 	 * about syntactically bogus color names even if they won't be used.
 	 */
 	if (!want_color(format->use_color))
 		color_parse("", atom->u.color);
+	return 0;
 }
 
-static void refname_atom_parser_internal(struct refname_atom *atom,
-					 const char *arg, const char *name)
+static int refname_atom_parser_internal(struct refname_atom *atom, const char *arg,
+					 const char *name, struct strbuf *err)
 {
 	if (!arg)
 		atom->option = R_NORMAL;
@@ -126,16 +142,18 @@
 		 skip_prefix(arg, "strip=", &arg)) {
 		atom->option = R_LSTRIP;
 		if (strtol_i(arg, 10, &atom->lstrip))
-			die(_("Integer value expected refname:lstrip=%s"), arg);
+			return strbuf_addf_ret(err, -1, _("Integer value expected refname:lstrip=%s"), arg);
 	} else if (skip_prefix(arg, "rstrip=", &arg)) {
 		atom->option = R_RSTRIP;
 		if (strtol_i(arg, 10, &atom->rstrip))
-			die(_("Integer value expected refname:rstrip=%s"), arg);
+			return strbuf_addf_ret(err, -1, _("Integer value expected refname:rstrip=%s"), arg);
 	} else
-		die(_("unrecognized %%(%s) argument: %s"), name, arg);
+		return strbuf_addf_ret(err, -1, _("unrecognized %%(%s) argument: %s"), name, arg);
+	return 0;
 }
 
-static void remote_ref_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
+static int remote_ref_atom_parser(const struct ref_format *format, struct used_atom *atom,
+				  const char *arg, struct strbuf *err)
 {
 	struct string_list params = STRING_LIST_INIT_DUP;
 	int i;
@@ -145,9 +163,8 @@
 
 	if (!arg) {
 		atom->u.remote_ref.option = RR_REF;
-		refname_atom_parser_internal(&atom->u.remote_ref.refname,
-					     arg, atom->name);
-		return;
+		return refname_atom_parser_internal(&atom->u.remote_ref.refname,
+						    arg, atom->name, err);
 	}
 
 	atom->u.remote_ref.nobracket = 0;
@@ -170,29 +187,38 @@
 			atom->u.remote_ref.push_remote = 1;
 		} else {
 			atom->u.remote_ref.option = RR_REF;
-			refname_atom_parser_internal(&atom->u.remote_ref.refname,
-						     arg, atom->name);
+			if (refname_atom_parser_internal(&atom->u.remote_ref.refname,
+							 arg, atom->name, err)) {
+				string_list_clear(&params, 0);
+				return -1;
+			}
 		}
 	}
 
 	string_list_clear(&params, 0);
+	return 0;
 }
 
-static void body_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
+static int body_atom_parser(const struct ref_format *format, struct used_atom *atom,
+			    const char *arg, struct strbuf *err)
 {
 	if (arg)
-		die(_("%%(body) does not take arguments"));
+		return strbuf_addf_ret(err, -1, _("%%(body) does not take arguments"));
 	atom->u.contents.option = C_BODY_DEP;
+	return 0;
 }
 
-static void subject_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
+static int subject_atom_parser(const struct ref_format *format, struct used_atom *atom,
+			       const char *arg, struct strbuf *err)
 {
 	if (arg)
-		die(_("%%(subject) does not take arguments"));
+		return strbuf_addf_ret(err, -1, _("%%(subject) does not take arguments"));
 	atom->u.contents.option = C_SUB;
+	return 0;
 }
 
-static void trailers_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
+static int trailers_atom_parser(const struct ref_format *format, struct used_atom *atom,
+				const char *arg, struct strbuf *err)
 {
 	struct string_list params = STRING_LIST_INIT_DUP;
 	int i;
@@ -205,15 +231,20 @@
 				atom->u.contents.trailer_opts.unfold = 1;
 			else if (!strcmp(s, "only"))
 				atom->u.contents.trailer_opts.only_trailers = 1;
-			else
-				die(_("unknown %%(trailers) argument: %s"), s);
+			else {
+				strbuf_addf(err, _("unknown %%(trailers) argument: %s"), s);
+				string_list_clear(&params, 0);
+				return -1;
+			}
 		}
 	}
 	atom->u.contents.option = C_TRAILERS;
 	string_list_clear(&params, 0);
+	return 0;
 }
 
-static void contents_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
+static int contents_atom_parser(const struct ref_format *format, struct used_atom *atom,
+				const char *arg, struct strbuf *err)
 {
 	if (!arg)
 		atom->u.contents.option = C_BARE;
@@ -225,16 +256,19 @@
 		atom->u.contents.option = C_SUB;
 	else if (skip_prefix(arg, "trailers", &arg)) {
 		skip_prefix(arg, ":", &arg);
-		trailers_atom_parser(format, atom, *arg ? arg : NULL);
+		if (trailers_atom_parser(format, atom, *arg ? arg : NULL, err))
+			return -1;
 	} else if (skip_prefix(arg, "lines=", &arg)) {
 		atom->u.contents.option = C_LINES;
 		if (strtoul_ui(arg, 10, &atom->u.contents.nlines))
-			die(_("positive value expected contents:lines=%s"), arg);
+			return strbuf_addf_ret(err, -1, _("positive value expected contents:lines=%s"), arg);
 	} else
-		die(_("unrecognized %%(contents) argument: %s"), arg);
+		return strbuf_addf_ret(err, -1, _("unrecognized %%(contents) argument: %s"), arg);
+	return 0;
 }
 
-static void objectname_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
+static int objectname_atom_parser(const struct ref_format *format, struct used_atom *atom,
+				  const char *arg, struct strbuf *err)
 {
 	if (!arg)
 		atom->u.objectname.option = O_FULL;
@@ -244,16 +278,18 @@
 		atom->u.objectname.option = O_LENGTH;
 		if (strtoul_ui(arg, 10, &atom->u.objectname.length) ||
 		    atom->u.objectname.length == 0)
-			die(_("positive value expected objectname:short=%s"), arg);
+			return strbuf_addf_ret(err, -1, _("positive value expected objectname:short=%s"), arg);
 		if (atom->u.objectname.length < MINIMUM_ABBREV)
 			atom->u.objectname.length = MINIMUM_ABBREV;
 	} else
-		die(_("unrecognized %%(objectname) argument: %s"), arg);
+		return strbuf_addf_ret(err, -1, _("unrecognized %%(objectname) argument: %s"), arg);
+	return 0;
 }
 
-static void refname_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
+static int refname_atom_parser(const struct ref_format *format, struct used_atom *atom,
+			       const char *arg, struct strbuf *err)
 {
-	refname_atom_parser_internal(&atom->u.refname, arg, atom->name);
+	return refname_atom_parser_internal(&atom->u.refname, arg, atom->name, err);
 }
 
 static align_type parse_align_position(const char *s)
@@ -267,7 +303,8 @@
 	return -1;
 }
 
-static void align_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
+static int align_atom_parser(const struct ref_format *format, struct used_atom *atom,
+			     const char *arg, struct strbuf *err)
 {
 	struct align *align = &atom->u.align;
 	struct string_list params = STRING_LIST_INIT_DUP;
@@ -275,7 +312,7 @@
 	unsigned int width = ~0U;
 
 	if (!arg)
-		die(_("expected format: %%(align:<width>,<position>)"));
+		return strbuf_addf_ret(err, -1, _("expected format: %%(align:<width>,<position>)"));
 
 	align->position = ALIGN_LEFT;
 
@@ -286,49 +323,65 @@
 
 		if (skip_prefix(s, "position=", &s)) {
 			position = parse_align_position(s);
-			if (position < 0)
-				die(_("unrecognized position:%s"), s);
+			if (position < 0) {
+				strbuf_addf(err, _("unrecognized position:%s"), s);
+				string_list_clear(&params, 0);
+				return -1;
+			}
 			align->position = position;
 		} else if (skip_prefix(s, "width=", &s)) {
-			if (strtoul_ui(s, 10, &width))
-				die(_("unrecognized width:%s"), s);
+			if (strtoul_ui(s, 10, &width)) {
+				strbuf_addf(err, _("unrecognized width:%s"), s);
+				string_list_clear(&params, 0);
+				return -1;
+			}
 		} else if (!strtoul_ui(s, 10, &width))
 			;
 		else if ((position = parse_align_position(s)) >= 0)
 			align->position = position;
-		else
-			die(_("unrecognized %%(align) argument: %s"), s);
+		else {
+			strbuf_addf(err, _("unrecognized %%(align) argument: %s"), s);
+			string_list_clear(&params, 0);
+			return -1;
+		}
 	}
 
-	if (width == ~0U)
-		die(_("positive width expected with the %%(align) atom"));
+	if (width == ~0U) {
+		string_list_clear(&params, 0);
+		return strbuf_addf_ret(err, -1, _("positive width expected with the %%(align) atom"));
+	}
 	align->width = width;
 	string_list_clear(&params, 0);
+	return 0;
 }
 
-static void if_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
+static int if_atom_parser(const struct ref_format *format, struct used_atom *atom,
+			  const char *arg, struct strbuf *err)
 {
 	if (!arg) {
 		atom->u.if_then_else.cmp_status = COMPARE_NONE;
-		return;
+		return 0;
 	} else if (skip_prefix(arg, "equals=", &atom->u.if_then_else.str)) {
 		atom->u.if_then_else.cmp_status = COMPARE_EQUAL;
 	} else if (skip_prefix(arg, "notequals=", &atom->u.if_then_else.str)) {
 		atom->u.if_then_else.cmp_status = COMPARE_UNEQUAL;
-	} else {
-		die(_("unrecognized %%(if) argument: %s"), arg);
-	}
+	} else
+		return strbuf_addf_ret(err, -1, _("unrecognized %%(if) argument: %s"), arg);
+	return 0;
 }
 
-static void head_atom_parser(const struct ref_format *format, struct used_atom *atom, const char *arg)
+static int head_atom_parser(const struct ref_format *format, struct used_atom *atom,
+			    const char *arg, struct strbuf *unused_err)
 {
 	atom->u.head = resolve_refdup("HEAD", RESOLVE_REF_READING, NULL, NULL);
+	return 0;
 }
 
 static struct {
 	const char *name;
 	cmp_type cmp_type;
-	void (*parser)(const struct ref_format *format, struct used_atom *atom, const char *arg);
+	int (*parser)(const struct ref_format *format, struct used_atom *atom,
+		      const char *arg, struct strbuf *err);
 } valid_atom[] = {
 	{ "refname" , FIELD_STR, refname_atom_parser },
 	{ "objecttype" },
@@ -387,7 +440,8 @@
 
 struct atom_value {
 	const char *s;
-	void (*handler)(struct atom_value *atomv, struct ref_formatting_state *state);
+	int (*handler)(struct atom_value *atomv, struct ref_formatting_state *state,
+		       struct strbuf *err);
 	uintmax_t value; /* used for sorting when not FIELD_STR */
 	struct used_atom *atom;
 };
@@ -396,7 +450,8 @@
  * Used to parse format string and sort specifiers
  */
 static int parse_ref_filter_atom(const struct ref_format *format,
-				 const char *atom, const char *ep)
+				 const char *atom, const char *ep,
+				 struct strbuf *err)
 {
 	const char *sp;
 	const char *arg;
@@ -406,7 +461,8 @@
 	if (*sp == '*' && sp < ep)
 		sp++; /* deref */
 	if (ep <= sp)
-		die(_("malformed field name: %.*s"), (int)(ep-atom), atom);
+		return strbuf_addf_ret(err, -1, _("malformed field name: %.*s"),
+				       (int)(ep-atom), atom);
 
 	/* Do we have the atom already used elsewhere? */
 	for (i = 0; i < used_atom_cnt; i++) {
@@ -432,7 +488,8 @@
 	}
 
 	if (ARRAY_SIZE(valid_atom) <= i)
-		die(_("unknown field name: %.*s"), (int)(ep-atom), atom);
+		return strbuf_addf_ret(err, -1, _("unknown field name: %.*s"),
+				       (int)(ep-atom), atom);
 
 	/* Add it in, including the deref prefix */
 	at = used_atom_cnt;
@@ -451,8 +508,8 @@
 		}
 	}
 	memset(&used_atom[at].u, 0, sizeof(used_atom[at].u));
-	if (valid_atom[i].parser)
-		valid_atom[i].parser(format, &used_atom[at], arg);
+	if (valid_atom[i].parser && valid_atom[i].parser(format, &used_atom[at], arg, err))
+		return -1;
 	if (*atom == '*')
 		need_tagged = 1;
 	if (!strcmp(valid_atom[i].name, "symref"))
@@ -481,7 +538,8 @@
 	}
 }
 
-static void append_atom(struct atom_value *v, struct ref_formatting_state *state)
+static int append_atom(struct atom_value *v, struct ref_formatting_state *state,
+		       struct strbuf *unused_err)
 {
 	/*
 	 * Quote formatting is only done when the stack has a single
@@ -493,6 +551,7 @@
 		quote_formatting(&state->stack->output, v->s, state->quote_style);
 	else
 		strbuf_addstr(&state->stack->output, v->s);
+	return 0;
 }
 
 static void push_stack_element(struct ref_formatting_stack **stack)
@@ -527,7 +586,8 @@
 	strbuf_release(&s);
 }
 
-static void align_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state)
+static int align_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
+			      struct strbuf *unused_err)
 {
 	struct ref_formatting_stack *new_stack;
 
@@ -535,6 +595,7 @@
 	new_stack = state->stack;
 	new_stack->at_end = end_align_handler;
 	new_stack->at_end_data = &atomv->atom->u.align;
+	return 0;
 }
 
 static void if_then_else_handler(struct ref_formatting_stack **stack)
@@ -572,7 +633,8 @@
 	free(if_then_else);
 }
 
-static void if_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state)
+static int if_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
+			   struct strbuf *unused_err)
 {
 	struct ref_formatting_stack *new_stack;
 	struct if_then_else *if_then_else = xcalloc(sizeof(struct if_then_else), 1);
@@ -584,6 +646,7 @@
 	new_stack = state->stack;
 	new_stack->at_end = if_then_else_handler;
 	new_stack->at_end_data = if_then_else;
+	return 0;
 }
 
 static int is_empty(const char *s)
@@ -596,7 +659,8 @@
 	return 1;
 }
 
-static void then_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state)
+static int then_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
+			     struct strbuf *err)
 {
 	struct ref_formatting_stack *cur = state->stack;
 	struct if_then_else *if_then_else = NULL;
@@ -604,11 +668,11 @@
 	if (cur->at_end == if_then_else_handler)
 		if_then_else = (struct if_then_else *)cur->at_end_data;
 	if (!if_then_else)
-		die(_("format: %%(then) atom used without an %%(if) atom"));
+		return strbuf_addf_ret(err, -1, _("format: %%(then) atom used without an %%(if) atom"));
 	if (if_then_else->then_atom_seen)
-		die(_("format: %%(then) atom used more than once"));
+		return strbuf_addf_ret(err, -1, _("format: %%(then) atom used more than once"));
 	if (if_then_else->else_atom_seen)
-		die(_("format: %%(then) atom used after %%(else)"));
+		return strbuf_addf_ret(err, -1, _("format: %%(then) atom used after %%(else)"));
 	if_then_else->then_atom_seen = 1;
 	/*
 	 * If the 'equals' or 'notequals' attribute is used then
@@ -624,9 +688,11 @@
 	} else if (cur->output.len && !is_empty(cur->output.buf))
 		if_then_else->condition_satisfied = 1;
 	strbuf_reset(&cur->output);
+	return 0;
 }
 
-static void else_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state)
+static int else_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
+			     struct strbuf *err)
 {
 	struct ref_formatting_stack *prev = state->stack;
 	struct if_then_else *if_then_else = NULL;
@@ -634,24 +700,26 @@
 	if (prev->at_end == if_then_else_handler)
 		if_then_else = (struct if_then_else *)prev->at_end_data;
 	if (!if_then_else)
-		die(_("format: %%(else) atom used without an %%(if) atom"));
+		return strbuf_addf_ret(err, -1, _("format: %%(else) atom used without an %%(if) atom"));
 	if (!if_then_else->then_atom_seen)
-		die(_("format: %%(else) atom used without a %%(then) atom"));
+		return strbuf_addf_ret(err, -1, _("format: %%(else) atom used without a %%(then) atom"));
 	if (if_then_else->else_atom_seen)
-		die(_("format: %%(else) atom used more than once"));
+		return strbuf_addf_ret(err, -1, _("format: %%(else) atom used more than once"));
 	if_then_else->else_atom_seen = 1;
 	push_stack_element(&state->stack);
 	state->stack->at_end_data = prev->at_end_data;
 	state->stack->at_end = prev->at_end;
+	return 0;
 }
 
-static void end_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state)
+static int end_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
+			    struct strbuf *err)
 {
 	struct ref_formatting_stack *current = state->stack;
 	struct strbuf s = STRBUF_INIT;
 
 	if (!current->at_end)
-		die(_("format: %%(end) atom used without corresponding atom"));
+		return strbuf_addf_ret(err, -1, _("format: %%(end) atom used without corresponding atom"));
 	current->at_end(&state->stack);
 
 	/*  Stack may have been popped within at_end(), hence reset the current pointer */
@@ -668,6 +736,7 @@
 	}
 	strbuf_release(&s);
 	pop_stack_element(&state->stack);
+	return 0;
 }
 
 /*
@@ -702,17 +771,21 @@
 
 	format->need_color_reset_at_eol = 0;
 	for (cp = format->format; *cp && (sp = find_next(cp)); ) {
+		struct strbuf err = STRBUF_INIT;
 		const char *color, *ep = strchr(sp, ')');
 		int at;
 
 		if (!ep)
 			return error(_("malformed format string %s"), sp);
 		/* sp points at "%(" and ep points at the closing ")" */
-		at = parse_ref_filter_atom(format, sp + 2, ep);
+		at = parse_ref_filter_atom(format, sp + 2, ep, &err);
+		if (at < 0)
+			die("%s", err.buf);
 		cp = ep + 1;
 
 		if (skip_prefix(used_atom[at].name, "color:", &color))
 			format->need_color_reset_at_eol = !!strcmp(color, "reset");
+		strbuf_release(&err);
 	}
 	if (format->need_color_reset_at_eol && !want_color(format->use_color))
 		format->need_color_reset_at_eol = 0;
@@ -751,7 +824,7 @@
 			v->s = xstrdup(find_unique_abbrev(oid, atom->u.objectname.length));
 			return 1;
 		} else
-			die("BUG: unknown %%(objectname) option");
+			BUG("unknown %%(objectname) option");
 	}
 	return 0;
 }
@@ -815,7 +888,7 @@
 		if (deref)
 			name++;
 		if (!strcmp(name, "tree")) {
-			v->s = xstrdup(oid_to_hex(&commit->tree->object.oid));
+			v->s = xstrdup(oid_to_hex(get_commit_tree_oid(commit)));
 		}
 		else if (!strcmp(name, "numparent")) {
 			v->value = commit_list_count(commit->parents);
@@ -1299,7 +1372,7 @@
 		else
 			*s = "";
 	} else
-		die("BUG: unhandled RR_* enum");
+		BUG("unhandled RR_* enum");
 }
 
 char *get_head_description(void)
@@ -1358,28 +1431,30 @@
 	return show_ref(&atom->u.refname, ref->refname);
 }
 
-static void get_object(struct ref_array_item *ref, const struct object_id *oid,
-		       int deref, struct object **obj)
+static int get_object(struct ref_array_item *ref, const struct object_id *oid,
+		       int deref, struct object **obj, struct strbuf *err)
 {
 	int eaten;
+	int ret = 0;
 	unsigned long size;
 	void *buf = get_obj(oid, obj, &size, &eaten);
 	if (!buf)
-		die(_("missing object %s for %s"),
-		    oid_to_hex(oid), ref->refname);
-	if (!*obj)
-		die(_("parse_object_buffer failed on %s for %s"),
-		    oid_to_hex(oid), ref->refname);
-
-	grab_values(ref->value, deref, *obj, buf, size);
+		ret = strbuf_addf_ret(err, -1, _("missing object %s for %s"),
+				      oid_to_hex(oid), ref->refname);
+	else if (!*obj)
+		ret = strbuf_addf_ret(err, -1, _("parse_object_buffer failed on %s for %s"),
+				      oid_to_hex(oid), ref->refname);
+	else
+		grab_values(ref->value, deref, *obj, buf, size);
 	if (!eaten)
 		free(buf);
+	return ret;
 }
 
 /*
  * Parse the object referred by ref, and grab needed value.
  */
-static void populate_value(struct ref_array_item *ref)
+static int populate_value(struct ref_array_item *ref, struct strbuf *err)
 {
 	struct object *obj;
 	int i;
@@ -1501,16 +1576,17 @@
 			break;
 	}
 	if (used_atom_cnt <= i)
-		return;
+		return 0;
 
-	get_object(ref, &ref->objectname, 0, &obj);
+	if (get_object(ref, &ref->objectname, 0, &obj, err))
+		return -1;
 
 	/*
 	 * If there is no atom that wants to know about tagged
 	 * object, we are done.
 	 */
 	if (!need_tagged || (obj->type != OBJ_TAG))
-		return;
+		return 0;
 
 	/*
 	 * If it is a tag object, see if we use a value that derefs
@@ -1524,20 +1600,23 @@
 	 * is not consistent with what deref_tag() does
 	 * which peels the onion to the core.
 	 */
-	get_object(ref, tagged, 1, &obj);
+	return get_object(ref, tagged, 1, &obj, err);
 }
 
 /*
  * Given a ref, return the value for the atom.  This lazily gets value
  * out of the object by calling populate value.
  */
-static void get_ref_atom_value(struct ref_array_item *ref, int atom, struct atom_value **v)
+static int get_ref_atom_value(struct ref_array_item *ref, int atom,
+			      struct atom_value **v, struct strbuf *err)
 {
 	if (!ref->value) {
-		populate_value(ref);
+		if (populate_value(ref, err))
+			return -1;
 		fill_missing_values(ref->value);
 	}
 	*v = &ref->value[atom];
+	return 0;
 }
 
 /*
@@ -2075,9 +2154,13 @@
 	int cmp;
 	cmp_type cmp_type = used_atom[s->atom].type;
 	int (*cmp_fn)(const char *, const char *);
+	struct strbuf err = STRBUF_INIT;
 
-	get_ref_atom_value(a, s->atom, &va);
-	get_ref_atom_value(b, s->atom, &vb);
+	if (get_ref_atom_value(a, s->atom, &va, &err))
+		die("%s", err.buf);
+	if (get_ref_atom_value(b, s->atom, &vb, &err))
+		die("%s", err.buf);
+	strbuf_release(&err);
 	cmp_fn = s->ignore_case ? strcasecmp : strcmp;
 	if (s->version)
 		cmp = versioncmp(va->s, vb->s);
@@ -2136,9 +2219,10 @@
 	}
 }
 
-void format_ref_array_item(struct ref_array_item *info,
+int format_ref_array_item(struct ref_array_item *info,
 			   const struct ref_format *format,
-			   struct strbuf *final_buf)
+			   struct strbuf *final_buf,
+			   struct strbuf *error_buf)
 {
 	const char *cp, *sp, *ep;
 	struct ref_formatting_state state = REF_FORMATTING_STATE_INIT;
@@ -2148,14 +2232,17 @@
 
 	for (cp = format->format; *cp && (sp = find_next(cp)); cp = ep + 1) {
 		struct atom_value *atomv;
+		int pos;
 
 		ep = strchr(sp, ')');
 		if (cp < sp)
 			append_literal(cp, sp, &state);
-		get_ref_atom_value(info,
-				   parse_ref_filter_atom(format, sp + 2, ep),
-				   &atomv);
-		atomv->handler(atomv, &state);
+		pos = parse_ref_filter_atom(format, sp + 2, ep, error_buf);
+		if (pos < 0 || get_ref_atom_value(info, pos, &atomv, error_buf) ||
+		    atomv->handler(atomv, &state, error_buf)) {
+			pop_stack_element(&state.stack);
+			return -1;
+		}
 	}
 	if (*cp) {
 		sp = cp + strlen(cp);
@@ -2164,21 +2251,30 @@
 	if (format->need_color_reset_at_eol) {
 		struct atom_value resetv;
 		resetv.s = GIT_COLOR_RESET;
-		append_atom(&resetv, &state);
+		if (append_atom(&resetv, &state, error_buf)) {
+			pop_stack_element(&state.stack);
+			return -1;
+		}
 	}
-	if (state.stack->prev)
-		die(_("format: %%(end) atom missing"));
+	if (state.stack->prev) {
+		pop_stack_element(&state.stack);
+		return strbuf_addf_ret(error_buf, -1, _("format: %%(end) atom missing"));
+	}
 	strbuf_addbuf(final_buf, &state.stack->output);
 	pop_stack_element(&state.stack);
+	return 0;
 }
 
 void show_ref_array_item(struct ref_array_item *info,
 			 const struct ref_format *format)
 {
 	struct strbuf final_buf = STRBUF_INIT;
+	struct strbuf error_buf = STRBUF_INIT;
 
-	format_ref_array_item(info, format, &final_buf);
+	if (format_ref_array_item(info, format, &final_buf, &error_buf))
+		die("%s", error_buf.buf);
 	fwrite(final_buf.buf, 1, final_buf.len, stdout);
+	strbuf_release(&error_buf);
 	strbuf_release(&final_buf);
 	putchar('\n');
 }
@@ -2201,7 +2297,12 @@
 	 */
 	struct ref_format dummy = REF_FORMAT_INIT;
 	const char *end = atom + strlen(atom);
-	return parse_ref_filter_atom(&dummy, atom, end);
+	struct strbuf err = STRBUF_INIT;
+	int res = parse_ref_filter_atom(&dummy, atom, end, &err);
+	if (res < 0)
+		die("%s", err.buf);
+	strbuf_release(&err);
+	return res;
 }
 
 /*  If no sorting option is given, use refname to sort as default */
diff --git a/ref-filter.h b/ref-filter.h
index 76cf87c..85c8ebc 100644
--- a/ref-filter.h
+++ b/ref-filter.h
@@ -110,9 +110,10 @@
 /*  Sort the given ref_array as per the ref_sorting provided */
 void ref_array_sort(struct ref_sorting *sort, struct ref_array *array);
 /*  Based on the given format and quote_style, fill the strbuf */
-void format_ref_array_item(struct ref_array_item *info,
-			   const struct ref_format *format,
-			   struct strbuf *final_buf);
+int format_ref_array_item(struct ref_array_item *info,
+			  const struct ref_format *format,
+			  struct strbuf *final_buf,
+			  struct strbuf *error_buf);
 /*  Print the ref using the given format and quote_style */
 void show_ref_array_item(struct ref_array_item *info, const struct ref_format *format);
 /*  Parse a single sort specifier and add it to the list */
diff --git a/refs.c b/refs.c
index f61ec58..0eb379f 100644
--- a/refs.c
+++ b/refs.c
@@ -13,6 +13,8 @@
 #include "tag.h"
 #include "submodule.h"
 #include "worktree.h"
+#include "argv-array.h"
+#include "repository.h"
 
 /*
  * List of all available backends
@@ -206,7 +208,7 @@
 char *resolve_refdup(const char *refname, int resolve_flags,
 		     struct object_id *oid, int *flags)
 {
-	return refs_resolve_refdup(get_main_ref_store(),
+	return refs_resolve_refdup(get_main_ref_store(the_repository),
 				   refname, resolve_flags,
 				   oid, flags);
 }
@@ -228,7 +230,7 @@
 
 int read_ref_full(const char *refname, int resolve_flags, struct object_id *oid, int *flags)
 {
-	return refs_read_ref_full(get_main_ref_store(), refname,
+	return refs_read_ref_full(get_main_ref_store(the_repository), refname,
 				  resolve_flags, oid, flags);
 }
 
@@ -301,7 +303,7 @@
 	struct object *o = lookup_unknown_object(name->hash);
 
 	if (o->type == OBJ_NONE) {
-		int type = oid_object_info(name, NULL);
+		int type = oid_object_info(the_repository, name, NULL);
 		if (type < 0 || !object_as_type(o, type, 0))
 			return PEEL_INVALID;
 	}
@@ -375,7 +377,7 @@
 
 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 {
-	return refs_for_each_tag_ref(get_main_ref_store(), fn, cb_data);
+	return refs_for_each_tag_ref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
 int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
@@ -385,7 +387,7 @@
 
 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 {
-	return refs_for_each_branch_ref(get_main_ref_store(), fn, cb_data);
+	return refs_for_each_branch_ref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
 int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
@@ -395,7 +397,7 @@
 
 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 {
-	return refs_for_each_remote_ref(get_main_ref_store(), fn, cb_data);
+	return refs_for_each_remote_ref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
@@ -502,6 +504,19 @@
 }
 
 /*
+ * Given a 'prefix' expand it by the rules in 'ref_rev_parse_rules' and add
+ * the results to 'prefixes'
+ */
+void expand_ref_prefix(struct argv_array *prefixes, const char *prefix)
+{
+	const char **p;
+	int len = strlen(prefix);
+
+	for (p = ref_rev_parse_rules; *p; p++)
+		argv_array_pushf(prefixes, *p, len, prefix);
+}
+
+/*
  * *string and *len will only be substituted, and *string returned (for
  * later free()ing) if the string passed in is a magic short-hand form
  * to name a branch.
@@ -645,7 +660,7 @@
 {
 	const char *filename;
 	int fd;
-	static struct lock_file lock;
+	struct lock_file lock = LOCK_INIT;
 	struct strbuf buf = STRBUF_INIT;
 	int ret = -1;
 
@@ -655,8 +670,7 @@
 	strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
 
 	filename = git_path("%s", pseudoref);
-	fd = hold_lock_file_for_update_timeout(&lock, filename,
-					       LOCK_DIE_ON_ERROR,
+	fd = hold_lock_file_for_update_timeout(&lock, filename, 0,
 					       get_files_ref_lock_timeout_ms());
 	if (fd < 0) {
 		strbuf_addf(err, "could not open '%s' for writing: %s",
@@ -667,10 +681,21 @@
 	if (old_oid) {
 		struct object_id actual_old_oid;
 
-		if (read_ref(pseudoref, &actual_old_oid))
-			die("could not read ref '%s'", pseudoref);
-		if (oidcmp(&actual_old_oid, old_oid)) {
-			strbuf_addf(err, "unexpected sha1 when writing '%s'", pseudoref);
+		if (read_ref(pseudoref, &actual_old_oid)) {
+			if (!is_null_oid(old_oid)) {
+				strbuf_addf(err, "could not read ref '%s'",
+					    pseudoref);
+				rollback_lock_file(&lock);
+				goto done;
+			}
+		} else if (is_null_oid(old_oid)) {
+			strbuf_addf(err, "ref '%s' already exists",
+				    pseudoref);
+			rollback_lock_file(&lock);
+			goto done;
+		} else if (oidcmp(&actual_old_oid, old_oid)) {
+			strbuf_addf(err, "unexpected object ID when writing '%s'",
+				    pseudoref);
 			rollback_lock_file(&lock);
 			goto done;
 		}
@@ -691,24 +716,28 @@
 
 static int delete_pseudoref(const char *pseudoref, const struct object_id *old_oid)
 {
-	static struct lock_file lock;
 	const char *filename;
 
 	filename = git_path("%s", pseudoref);
 
 	if (old_oid && !is_null_oid(old_oid)) {
+		struct lock_file lock = LOCK_INIT;
 		int fd;
 		struct object_id actual_old_oid;
 
 		fd = hold_lock_file_for_update_timeout(
-				&lock, filename, LOCK_DIE_ON_ERROR,
+				&lock, filename, 0,
 				get_files_ref_lock_timeout_ms());
-		if (fd < 0)
-			die_errno(_("Could not open '%s' for writing"), filename);
+		if (fd < 0) {
+			error_errno(_("could not open '%s' for writing"),
+				    filename);
+			return -1;
+		}
 		if (read_ref(pseudoref, &actual_old_oid))
 			die("could not read ref '%s'", pseudoref);
 		if (oidcmp(&actual_old_oid, old_oid)) {
-			warning("Unexpected sha1 when deleting %s", pseudoref);
+			error("unexpected object ID when deleting '%s'",
+			      pseudoref);
 			rollback_lock_file(&lock);
 			return -1;
 		}
@@ -731,7 +760,7 @@
 	struct strbuf err = STRBUF_INIT;
 
 	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
-		assert(refs == get_main_ref_store());
+		assert(refs == get_main_ref_store(the_repository));
 		return delete_pseudoref(refname, old_oid);
 	}
 
@@ -753,7 +782,7 @@
 int delete_ref(const char *msg, const char *refname,
 	       const struct object_id *old_oid, unsigned int flags)
 {
-	return refs_delete_ref(get_main_ref_store(), msg, refname,
+	return refs_delete_ref(get_main_ref_store(the_repository), msg, refname,
 			       old_oid, flags);
 }
 
@@ -929,7 +958,7 @@
 
 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 {
-	return ref_store_transaction_begin(get_main_ref_store(), err);
+	return ref_store_transaction_begin(get_main_ref_store(the_repository), err);
 }
 
 void ref_transaction_free(struct ref_transaction *transaction)
@@ -945,10 +974,10 @@
 		/* OK */
 		break;
 	case REF_TRANSACTION_PREPARED:
-		die("BUG: free called on a prepared reference transaction");
+		BUG("free called on a prepared reference transaction");
 		break;
 	default:
-		die("BUG: unexpected reference transaction state");
+		BUG("unexpected reference transaction state");
 		break;
 	}
 
@@ -970,7 +999,7 @@
 	struct ref_update *update;
 
 	if (transaction->state != REF_TRANSACTION_OPEN)
-		die("BUG: update called for transaction that is not open");
+		BUG("update called for transaction that is not open");
 
 	FLEX_ALLOC_STR(update, refname, refname);
 	ALLOC_GROW(transaction->updates, transaction->nr + 1, transaction->alloc);
@@ -1020,7 +1049,7 @@
 			   struct strbuf *err)
 {
 	if (!new_oid || is_null_oid(new_oid))
-		die("BUG: create called without valid new_oid");
+		BUG("create called without valid new_oid");
 	return ref_transaction_update(transaction, refname, new_oid,
 				      &null_oid, flags, msg, err);
 }
@@ -1032,7 +1061,7 @@
 			   struct strbuf *err)
 {
 	if (old_oid && is_null_oid(old_oid))
-		die("BUG: delete called with old_oid set to zeros");
+		BUG("delete called with old_oid set to zeros");
 	return ref_transaction_update(transaction, refname,
 				      &null_oid, old_oid,
 				      flags, msg, err);
@@ -1045,7 +1074,7 @@
 			   struct strbuf *err)
 {
 	if (!old_oid)
-		die("BUG: verify called with old_oid set to NULL");
+		BUG("verify called with old_oid set to NULL");
 	return ref_transaction_update(transaction, refname,
 				      NULL, old_oid,
 				      flags, NULL, err);
@@ -1061,7 +1090,7 @@
 	int ret = 0;
 
 	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
-		assert(refs == get_main_ref_store());
+		assert(refs == get_main_ref_store(the_repository));
 		ret = write_pseudoref(refname, new_oid, old_oid, &err);
 	} else {
 		t = ref_store_transaction_begin(refs, &err);
@@ -1100,7 +1129,7 @@
 	       const struct object_id *old_oid,
 	       unsigned int flags, enum action_on_err onerr)
 {
-	return refs_update_ref(get_main_ref_store(), msg, refname, new_oid,
+	return refs_update_ref(get_main_ref_store(the_repository), msg, refname, new_oid,
 			       old_oid, flags, onerr);
 }
 
@@ -1133,8 +1162,8 @@
 		for (i = 0; i < nr_rules; i++) {
 			assert(offset < total_len);
 			scanf_fmts[i] = (char *)&scanf_fmts[nr_rules] + offset;
-			offset += snprintf(scanf_fmts[i], total_len - offset,
-					   ref_rev_parse_rules[i], 2, "%s") + 1;
+			offset += xsnprintf(scanf_fmts[i], total_len - offset,
+					    ref_rev_parse_rules[i], 2, "%s") + 1;
 		}
 	}
 
@@ -1321,7 +1350,7 @@
 
 int head_ref(each_ref_fn fn, void *cb_data)
 {
-	return refs_head_ref(get_main_ref_store(), fn, cb_data);
+	return refs_head_ref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
 struct ref_iterator *refs_ref_iterator_begin(
@@ -1380,7 +1409,7 @@
 
 int for_each_ref(each_ref_fn fn, void *cb_data)
 {
-	return refs_for_each_ref(get_main_ref_store(), fn, cb_data);
+	return refs_for_each_ref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
 int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
@@ -1391,7 +1420,7 @@
 
 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 {
-	return refs_for_each_ref_in(get_main_ref_store(), prefix, fn, cb_data);
+	return refs_for_each_ref_in(get_main_ref_store(the_repository), prefix, fn, cb_data);
 }
 
 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
@@ -1400,7 +1429,7 @@
 
 	if (broken)
 		flag = DO_FOR_EACH_INCLUDE_BROKEN;
-	return do_for_each_ref(get_main_ref_store(),
+	return do_for_each_ref(get_main_ref_store(the_repository),
 			       prefix, fn, 0, flag, cb_data);
 }
 
@@ -1415,9 +1444,9 @@
 	return do_for_each_ref(refs, prefix, fn, 0, flag, cb_data);
 }
 
-int for_each_replace_ref(each_ref_fn fn, void *cb_data)
+int for_each_replace_ref(struct repository *r, each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(get_main_ref_store(),
+	return do_for_each_ref(get_main_ref_store(r),
 			       git_replace_ref_base, fn,
 			       strlen(git_replace_ref_base),
 			       DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
@@ -1428,7 +1457,7 @@
 	struct strbuf buf = STRBUF_INIT;
 	int ret;
 	strbuf_addf(&buf, "%srefs/", get_git_namespace());
-	ret = do_for_each_ref(get_main_ref_store(),
+	ret = do_for_each_ref(get_main_ref_store(the_repository),
 			      buf.buf, fn, 0, 0, cb_data);
 	strbuf_release(&buf);
 	return ret;
@@ -1442,7 +1471,7 @@
 
 int for_each_rawref(each_ref_fn fn, void *cb_data)
 {
-	return refs_for_each_rawref(get_main_ref_store(), fn, cb_data);
+	return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
 int refs_read_raw_ref(struct ref_store *ref_store,
@@ -1548,7 +1577,7 @@
 /* backend functions */
 int refs_init_db(struct strbuf *err)
 {
-	struct ref_store *refs = get_main_ref_store();
+	struct ref_store *refs = get_main_ref_store(the_repository);
 
 	return refs->be->init_db(refs, err);
 }
@@ -1556,7 +1585,7 @@
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       struct object_id *oid, int *flags)
 {
-	return refs_resolve_ref_unsafe(get_main_ref_store(), refname,
+	return refs_resolve_ref_unsafe(get_main_ref_store(the_repository), refname,
 				       resolve_flags, oid, flags);
 }
 
@@ -1608,9 +1637,6 @@
 	return entry;
 }
 
-/* A pointer to the ref_store for the main repository: */
-static struct ref_store *main_ref_store;
-
 /* A hashmap of ref_stores, stored by submodule name: */
 static struct hashmap submodule_ref_stores;
 
@@ -1646,19 +1672,22 @@
 	struct ref_store *refs;
 
 	if (!be)
-		die("BUG: reference backend %s is unknown", be_name);
+		BUG("reference backend %s is unknown", be_name);
 
 	refs = be->init(gitdir, flags);
 	return refs;
 }
 
-struct ref_store *get_main_ref_store(void)
+struct ref_store *get_main_ref_store(struct repository *r)
 {
-	if (main_ref_store)
-		return main_ref_store;
+	if (r->refs)
+		return r->refs;
 
-	main_ref_store = ref_store_init(get_git_dir(), REF_STORE_ALL_CAPS);
-	return main_ref_store;
+	if (!r->gitdir)
+		BUG("attempting to get main_ref_store outside of repository");
+
+	r->refs = ref_store_init(r->gitdir, REF_STORE_ALL_CAPS);
+	return r->refs;
 }
 
 /*
@@ -1674,7 +1703,7 @@
 		hashmap_init(map, ref_store_hash_cmp, NULL, 0);
 
 	if (hashmap_put(map, alloc_ref_store_hash_entry(name, refs)))
-		die("BUG: %s ref_store '%s' initialized twice", type, name);
+		BUG("%s ref_store '%s' initialized twice", type, name);
 }
 
 struct ref_store *get_submodule_ref_store(const char *submodule)
@@ -1727,7 +1756,7 @@
 	const char *id;
 
 	if (wt->is_current)
-		return get_main_ref_store();
+		return get_main_ref_store(the_repository);
 
 	id = wt->id ? wt->id : "/";
 	refs = lookup_ref_store_map(&worktree_ref_stores, id);
@@ -1783,7 +1812,7 @@
 
 int peel_ref(const char *refname, struct object_id *oid)
 {
-	return refs_peel_ref(get_main_ref_store(), refname, oid);
+	return refs_peel_ref(get_main_ref_store(the_repository), refname, oid);
 }
 
 int refs_create_symref(struct ref_store *refs,
@@ -1799,7 +1828,7 @@
 int create_symref(const char *ref_target, const char *refs_heads_master,
 		  const char *logmsg)
 {
-	return refs_create_symref(get_main_ref_store(), ref_target,
+	return refs_create_symref(get_main_ref_store(the_repository), ref_target,
 				  refs_heads_master, logmsg);
 }
 
@@ -1820,7 +1849,7 @@
 				    refnames->items[i].string);
 			return 1;
 		} else if (cmp > 0) {
-			die("BUG: ref_update_reject_duplicates() received unsorted list");
+			BUG("ref_update_reject_duplicates() received unsorted list");
 		}
 	}
 	return 0;
@@ -1836,13 +1865,13 @@
 		/* Good. */
 		break;
 	case REF_TRANSACTION_PREPARED:
-		die("BUG: prepare called twice on reference transaction");
+		BUG("prepare called twice on reference transaction");
 		break;
 	case REF_TRANSACTION_CLOSED:
-		die("BUG: prepare called on a closed reference transaction");
+		BUG("prepare called on a closed reference transaction");
 		break;
 	default:
-		die("BUG: unexpected reference transaction state");
+		BUG("unexpected reference transaction state");
 		break;
 	}
 
@@ -1869,10 +1898,10 @@
 		ret = refs->be->transaction_abort(refs, transaction, err);
 		break;
 	case REF_TRANSACTION_CLOSED:
-		die("BUG: abort called on a closed reference transaction");
+		BUG("abort called on a closed reference transaction");
 		break;
 	default:
-		die("BUG: unexpected reference transaction state");
+		BUG("unexpected reference transaction state");
 		break;
 	}
 
@@ -1897,10 +1926,10 @@
 		/* Fall through to finish. */
 		break;
 	case REF_TRANSACTION_CLOSED:
-		die("BUG: commit called on a closed reference transaction");
+		BUG("commit called on a closed reference transaction");
 		break;
 	default:
-		die("BUG: unexpected reference transaction state");
+		BUG("unexpected reference transaction state");
 		break;
 	}
 
@@ -1981,7 +2010,7 @@
 	}
 
 	if (ok != ITER_DONE)
-		die("BUG: error while iterating over references");
+		BUG("error while iterating over references");
 
 	extra_refname = find_descendant_ref(dirname.buf, extras, skip);
 	if (extra_refname)
@@ -2007,7 +2036,7 @@
 
 int for_each_reflog(each_ref_fn fn, void *cb_data)
 {
-	return refs_for_each_reflog(get_main_ref_store(), fn, cb_data);
+	return refs_for_each_reflog(get_main_ref_store(the_repository), fn, cb_data);
 }
 
 int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
@@ -2022,7 +2051,7 @@
 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 				void *cb_data)
 {
-	return refs_for_each_reflog_ent_reverse(get_main_ref_store(),
+	return refs_for_each_reflog_ent_reverse(get_main_ref_store(the_repository),
 						refname, fn, cb_data);
 }
 
@@ -2035,7 +2064,7 @@
 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
 			void *cb_data)
 {
-	return refs_for_each_reflog_ent(get_main_ref_store(), refname,
+	return refs_for_each_reflog_ent(get_main_ref_store(the_repository), refname,
 					fn, cb_data);
 }
 
@@ -2046,7 +2075,7 @@
 
 int reflog_exists(const char *refname)
 {
-	return refs_reflog_exists(get_main_ref_store(), refname);
+	return refs_reflog_exists(get_main_ref_store(the_repository), refname);
 }
 
 int refs_create_reflog(struct ref_store *refs, const char *refname,
@@ -2058,7 +2087,7 @@
 int safe_create_reflog(const char *refname, int force_create,
 		       struct strbuf *err)
 {
-	return refs_create_reflog(get_main_ref_store(), refname,
+	return refs_create_reflog(get_main_ref_store(the_repository), refname,
 				  force_create, err);
 }
 
@@ -2069,7 +2098,7 @@
 
 int delete_reflog(const char *refname)
 {
-	return refs_delete_reflog(get_main_ref_store(), refname);
+	return refs_delete_reflog(get_main_ref_store(the_repository), refname);
 }
 
 int refs_reflog_expire(struct ref_store *refs,
@@ -2092,7 +2121,7 @@
 		  reflog_expiry_cleanup_fn cleanup_fn,
 		  void *policy_cb_data)
 {
-	return refs_reflog_expire(get_main_ref_store(),
+	return refs_reflog_expire(get_main_ref_store(the_repository),
 				  refname, oid, flags,
 				  prepare_fn, should_prune_fn,
 				  cleanup_fn, policy_cb_data);
@@ -2115,7 +2144,7 @@
 int delete_refs(const char *msg, struct string_list *refnames,
 		unsigned int flags)
 {
-	return refs_delete_refs(get_main_ref_store(), msg, refnames, flags);
+	return refs_delete_refs(get_main_ref_store(the_repository), msg, refnames, flags);
 }
 
 int refs_rename_ref(struct ref_store *refs, const char *oldref,
@@ -2126,7 +2155,7 @@
 
 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 {
-	return refs_rename_ref(get_main_ref_store(), oldref, newref, logmsg);
+	return refs_rename_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
 }
 
 int refs_copy_existing_ref(struct ref_store *refs, const char *oldref,
@@ -2137,5 +2166,5 @@
 
 int copy_existing_ref(const char *oldref, const char *newref, const char *logmsg)
 {
-	return refs_copy_existing_ref(get_main_ref_store(), oldref, newref, logmsg);
+	return refs_copy_existing_ref(get_main_ref_store(the_repository), oldref, newref, logmsg);
 }
diff --git a/refs.h b/refs.h
index 01be5ae..cc2fb4c 100644
--- a/refs.h
+++ b/refs.h
@@ -139,6 +139,13 @@
  */
 int refname_match(const char *abbrev_name, const char *full_name);
 
+/*
+ * Given a 'prefix' expand it by the rules in 'ref_rev_parse_rules' and add
+ * the results to 'prefixes'
+ */
+struct argv_array;
+void expand_ref_prefix(struct argv_array *prefixes, const char *prefix);
+
 int expand_ref(const char *str, int len, struct object_id *oid, char **ref);
 int dwim_ref(const char *str, int len, struct object_id *oid, char **ref);
 int dwim_log(const char *str, int len, struct object_id *oid, char **ref);
@@ -300,7 +307,7 @@
 int for_each_tag_ref(each_ref_fn fn, void *cb_data);
 int for_each_branch_ref(each_ref_fn fn, void *cb_data);
 int for_each_remote_ref(each_ref_fn fn, void *cb_data);
-int for_each_replace_ref(each_ref_fn fn, void *cb_data);
+int for_each_replace_ref(struct repository *r, each_ref_fn fn, void *cb_data);
 int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data);
 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
 			 const char *prefix, void *cb_data);
@@ -758,7 +765,7 @@
 
 int ref_storage_backend_exists(const char *name);
 
-struct ref_store *get_main_ref_store(void);
+struct ref_store *get_main_ref_store(struct repository *r);
 /*
  * Return the ref_store instance for the specified submodule. For the
  * main repository, use submodule==NULL; such a call cannot fail. For
diff --git a/refs/files-backend.c b/refs/files-backend.c
index a92a2aa..a9a066d 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -62,10 +62,6 @@
 	struct object_id old_oid;
 };
 
-/*
- * Future: need to be in "struct repository"
- * when doing a full libification.
- */
 struct files_ref_store {
 	struct ref_store base;
 	unsigned int store_flags;
@@ -125,7 +121,7 @@
 	if (refs->store_flags & REF_STORE_MAIN)
 		return;
 
-	die("BUG: operation %s only allowed for main ref store", caller);
+	BUG("operation %s only allowed for main ref store", caller);
 }
 
 /*
@@ -141,13 +137,13 @@
 	struct files_ref_store *refs;
 
 	if (ref_store->be != &refs_be_files)
-		die("BUG: ref_store is type \"%s\" not \"files\" in %s",
+		BUG("ref_store is type \"%s\" not \"files\" in %s",
 		    ref_store->be->name, caller);
 
 	refs = (struct files_ref_store *)ref_store;
 
 	if ((refs->store_flags & required_flags) != required_flags)
-		die("BUG: operation %s requires abilities 0x%x, but only have 0x%x",
+		BUG("operation %s requires abilities 0x%x, but only have 0x%x",
 		    caller, required_flags, refs->store_flags);
 
 	return refs;
@@ -166,7 +162,7 @@
 		strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
 		break;
 	default:
-		die("BUG: unknown ref type %d of ref %s",
+		BUG("unknown ref type %d of ref %s",
 		    ref_type(refname), refname);
 	}
 }
@@ -184,7 +180,7 @@
 		strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
 		break;
 	default:
-		die("BUG: unknown ref type %d of ref %s",
+		BUG("unknown ref type %d of ref %s",
 		    ref_type(refname), refname);
 	}
 }
@@ -2010,7 +2006,7 @@
 
 	}
 	if (!ret && sb.len)
-		die("BUG: reverse reflog parser had leftover data");
+		BUG("reverse reflog parser had leftover data");
 
 	fclose(logfp);
 	strbuf_release(&sb);
@@ -2088,7 +2084,7 @@
 static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
 				   struct object_id *peeled)
 {
-	die("BUG: ref_iterator_peel() called for reflog_iterator");
+	BUG("ref_iterator_peel() called for reflog_iterator");
 }
 
 static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
@@ -2873,7 +2869,7 @@
 	assert(err);
 
 	if (transaction->state != REF_TRANSACTION_OPEN)
-		die("BUG: commit called for transaction that is not open");
+		BUG("commit called for transaction that is not open");
 
 	/* Fail if a refname appears more than once in the transaction: */
 	for (i = 0; i < transaction->nr; i++)
@@ -2899,7 +2895,7 @@
 	 */
 	if (refs_for_each_rawref(&refs->base, ref_present,
 				 &affected_refnames))
-		die("BUG: initial ref transaction called with existing refs");
+		BUG("initial ref transaction called with existing refs");
 
 	packed_transaction = ref_store_transaction_begin(refs->packed_ref_store, err);
 	if (!packed_transaction) {
@@ -2912,7 +2908,7 @@
 
 		if ((update->flags & REF_HAVE_OLD) &&
 		    !is_null_oid(&update->old_oid))
-			die("BUG: initial ref transaction with old_sha1 set");
+			BUG("initial ref transaction with old_sha1 set");
 		if (refs_verify_refname_available(&refs->base, update->refname,
 						  &affected_refnames, NULL,
 						  err)) {
@@ -2995,7 +2991,7 @@
 {
 	struct files_ref_store *refs =
 		files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
-	static struct lock_file reflog_lock;
+	struct lock_file reflog_lock = LOCK_INIT;
 	struct expire_reflog_cb cb;
 	struct ref_lock *lock;
 	struct strbuf log_file_sb = STRBUF_INIT;
diff --git a/refs/iterator.c b/refs/iterator.c
index bd35da4..2ac91ac 100644
--- a/refs/iterator.c
+++ b/refs/iterator.c
@@ -54,7 +54,7 @@
 static int empty_ref_iterator_peel(struct ref_iterator *ref_iterator,
 				   struct object_id *peeled)
 {
-	die("BUG: peel called for empty iterator");
+	BUG("peel called for empty iterator");
 }
 
 static int empty_ref_iterator_abort(struct ref_iterator *ref_iterator)
@@ -177,7 +177,7 @@
 		(struct merge_ref_iterator *)ref_iterator;
 
 	if (!iter->current) {
-		die("BUG: peel called before advance for merge iterator");
+		BUG("peel called before advance for merge iterator");
 	}
 	return ref_iterator_peel(*iter->current, peeled);
 }
@@ -338,7 +338,7 @@
 			 * trimming, report it as a bug:
 			 */
 			if (strlen(iter->iter0->refname) <= iter->trim)
-				die("BUG: attempt to trim too many characters");
+				BUG("attempt to trim too many characters");
 			iter->base.refname = iter->iter0->refname + iter->trim;
 		} else {
 			iter->base.refname = iter->iter0->refname;
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 369c34f..cec3fb9 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -221,13 +221,13 @@
 	struct packed_ref_store *refs;
 
 	if (ref_store->be != &refs_be_packed)
-		die("BUG: ref_store is type \"%s\" not \"packed\" in %s",
+		BUG("ref_store is type \"%s\" not \"packed\" in %s",
 		    ref_store->be->name, caller);
 
 	refs = (struct packed_ref_store *)ref_store;
 
 	if ((refs->store_flags & required_flags) != required_flags)
-		die("BUG: unallowed operation (%s), requires %x, has %x\n",
+		BUG("unallowed operation (%s), requires %x, has %x\n",
 		    caller, required_flags, refs->store_flags);
 
 	return refs;
@@ -1036,7 +1036,7 @@
 			"packed_refs_unlock");
 
 	if (!is_lock_file_locked(&refs->lock))
-		die("BUG: packed_refs_unlock() called when not locked");
+		BUG("packed_refs_unlock() called when not locked");
 	rollback_lock_file(&refs->lock);
 }
 
@@ -1089,7 +1089,7 @@
 	char *packed_refs_path;
 
 	if (!is_lock_file_locked(&refs->lock))
-		die("BUG: write_with_updates() called while unlocked");
+		BUG("write_with_updates() called while unlocked");
 
 	/*
 	 * If packed-refs is a symlink, we want to overwrite the
@@ -1563,21 +1563,21 @@
 			       const char *refname, const char *target,
 			       const char *logmsg)
 {
-	die("BUG: packed reference store does not support symrefs");
+	BUG("packed reference store does not support symrefs");
 }
 
 static int packed_rename_ref(struct ref_store *ref_store,
 			    const char *oldrefname, const char *newrefname,
 			    const char *logmsg)
 {
-	die("BUG: packed reference store does not support renaming references");
+	BUG("packed reference store does not support renaming references");
 }
 
 static int packed_copy_ref(struct ref_store *ref_store,
 			   const char *oldrefname, const char *newrefname,
 			   const char *logmsg)
 {
-	die("BUG: packed reference store does not support copying references");
+	BUG("packed reference store does not support copying references");
 }
 
 static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_store)
@@ -1610,7 +1610,7 @@
 			       const char *refname, int force_create,
 			       struct strbuf *err)
 {
-	die("BUG: packed reference store does not support reflogs");
+	BUG("packed reference store does not support reflogs");
 }
 
 static int packed_delete_reflog(struct ref_store *ref_store,
diff --git a/refs/ref-cache.c b/refs/ref-cache.c
index e90bd3e..9b110c8 100644
--- a/refs/ref-cache.c
+++ b/refs/ref-cache.c
@@ -23,7 +23,7 @@
 	dir = &entry->u.subdir;
 	if (entry->flag & REF_INCOMPLETE) {
 		if (!dir->cache->fill_ref_dir)
-			die("BUG: incomplete ref_store without fill_ref_dir function");
+			BUG("incomplete ref_store without fill_ref_dir function");
 
 		dir->cache->fill_ref_dir(dir->cache->ref_store, dir, entry->name);
 		entry->flag &= ~REF_INCOMPLETE;
diff --git a/refspec.c b/refspec.c
new file mode 100644
index 0000000..78edc48
--- /dev/null
+++ b/refspec.c
@@ -0,0 +1,227 @@
+#include "cache.h"
+#include "argv-array.h"
+#include "refs.h"
+#include "refspec.h"
+
+static struct refspec_item s_tag_refspec = {
+	0,
+	1,
+	0,
+	0,
+	"refs/tags/*",
+	"refs/tags/*"
+};
+
+/* See TAG_REFSPEC for the string version */
+const struct refspec_item *tag_refspec = &s_tag_refspec;
+
+/*
+ * Parses the provided refspec 'refspec' and populates the refspec_item 'item'.
+ * Returns 1 if successful and 0 if the refspec is invalid.
+ */
+static int parse_refspec(struct refspec_item *item, const char *refspec, int fetch)
+{
+	size_t llen;
+	int is_glob;
+	const char *lhs, *rhs;
+	int flags;
+
+	is_glob = 0;
+
+	lhs = refspec;
+	if (*lhs == '+') {
+		item->force = 1;
+		lhs++;
+	}
+
+	rhs = strrchr(lhs, ':');
+
+	/*
+	 * Before going on, special case ":" (or "+:") as a refspec
+	 * for pushing matching refs.
+	 */
+	if (!fetch && rhs == lhs && rhs[1] == '\0') {
+		item->matching = 1;
+		return 1;
+	}
+
+	if (rhs) {
+		size_t rlen = strlen(++rhs);
+		is_glob = (1 <= rlen && strchr(rhs, '*'));
+		item->dst = xstrndup(rhs, rlen);
+	} else {
+		item->dst = NULL;
+	}
+
+	llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
+	if (1 <= llen && memchr(lhs, '*', llen)) {
+		if ((rhs && !is_glob) || (!rhs && fetch))
+			return 0;
+		is_glob = 1;
+	} else if (rhs && is_glob) {
+		return 0;
+	}
+
+	item->pattern = is_glob;
+	item->src = xstrndup(lhs, llen);
+	flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
+
+	if (fetch) {
+		struct object_id unused;
+
+		/* LHS */
+		if (!*item->src)
+			; /* empty is ok; it means "HEAD" */
+		else if (llen == GIT_SHA1_HEXSZ && !get_oid_hex(item->src, &unused))
+			item->exact_sha1 = 1; /* ok */
+		else if (!check_refname_format(item->src, flags))
+			; /* valid looking ref is ok */
+		else
+			return 0;
+		/* RHS */
+		if (!item->dst)
+			; /* missing is ok; it is the same as empty */
+		else if (!*item->dst)
+			; /* empty is ok; it means "do not store" */
+		else if (!check_refname_format(item->dst, flags))
+			; /* valid looking ref is ok */
+		else
+			return 0;
+	} else {
+		/*
+		 * LHS
+		 * - empty is allowed; it means delete.
+		 * - when wildcarded, it must be a valid looking ref.
+		 * - otherwise, it must be an extended SHA-1, but
+		 *   there is no existing way to validate this.
+		 */
+		if (!*item->src)
+			; /* empty is ok */
+		else if (is_glob) {
+			if (check_refname_format(item->src, flags))
+				return 0;
+		}
+		else
+			; /* anything goes, for now */
+		/*
+		 * RHS
+		 * - missing is allowed, but LHS then must be a
+		 *   valid looking ref.
+		 * - empty is not allowed.
+		 * - otherwise it must be a valid looking ref.
+		 */
+		if (!item->dst) {
+			if (check_refname_format(item->src, flags))
+				return 0;
+		} else if (!*item->dst) {
+			return 0;
+		} else {
+			if (check_refname_format(item->dst, flags))
+				return 0;
+		}
+	}
+
+	return 1;
+}
+
+void refspec_item_init(struct refspec_item *item, const char *refspec, int fetch)
+{
+	memset(item, 0, sizeof(*item));
+
+	if (!parse_refspec(item, refspec, fetch))
+		die("Invalid refspec '%s'", refspec);
+}
+
+void refspec_item_clear(struct refspec_item *item)
+{
+	FREE_AND_NULL(item->src);
+	FREE_AND_NULL(item->dst);
+	item->force = 0;
+	item->pattern = 0;
+	item->matching = 0;
+	item->exact_sha1 = 0;
+}
+
+void refspec_init(struct refspec *rs, int fetch)
+{
+	memset(rs, 0, sizeof(*rs));
+	rs->fetch = fetch;
+}
+
+void refspec_append(struct refspec *rs, const char *refspec)
+{
+	struct refspec_item item;
+
+	refspec_item_init(&item, refspec, rs->fetch);
+
+	ALLOC_GROW(rs->items, rs->nr + 1, rs->alloc);
+	rs->items[rs->nr++] = item;
+
+	ALLOC_GROW(rs->raw, rs->raw_nr + 1, rs->raw_alloc);
+	rs->raw[rs->raw_nr++] = xstrdup(refspec);
+}
+
+void refspec_appendn(struct refspec *rs, const char **refspecs, int nr)
+{
+	int i;
+	for (i = 0; i < nr; i++)
+		refspec_append(rs, refspecs[i]);
+}
+
+void refspec_clear(struct refspec *rs)
+{
+	int i;
+
+	for (i = 0; i < rs->nr; i++)
+		refspec_item_clear(&rs->items[i]);
+
+	FREE_AND_NULL(rs->items);
+	rs->alloc = 0;
+	rs->nr = 0;
+
+	for (i = 0; i < rs->raw_nr; i++)
+		free((char *)rs->raw[i]);
+	FREE_AND_NULL(rs->raw);
+	rs->raw_alloc = 0;
+	rs->raw_nr = 0;
+
+	rs->fetch = 0;
+}
+
+int valid_fetch_refspec(const char *fetch_refspec_str)
+{
+	struct refspec_item refspec;
+	int ret = parse_refspec(&refspec, fetch_refspec_str, REFSPEC_FETCH);
+	refspec_item_clear(&refspec);
+	return ret;
+}
+
+void refspec_ref_prefixes(const struct refspec *rs,
+			  struct argv_array *ref_prefixes)
+{
+	int i;
+	for (i = 0; i < rs->nr; i++) {
+		const struct refspec_item *item = &rs->items[i];
+		const char *prefix = NULL;
+
+		if (item->exact_sha1)
+			continue;
+		if (rs->fetch == REFSPEC_FETCH)
+			prefix = item->src;
+		else if (item->dst)
+			prefix = item->dst;
+		else if (item->src && !item->exact_sha1)
+			prefix = item->src;
+
+		if (prefix) {
+			if (item->pattern) {
+				const char *glob = strchr(prefix, '*');
+				argv_array_pushf(ref_prefixes, "%.*s",
+						 (int)(glob - prefix),
+						 prefix);
+			} else {
+				expand_ref_prefix(ref_prefixes, prefix);
+			}
+		}
+	}
+}
diff --git a/refspec.h b/refspec.h
new file mode 100644
index 0000000..3a93638
--- /dev/null
+++ b/refspec.h
@@ -0,0 +1,52 @@
+#ifndef REFSPEC_H
+#define REFSPEC_H
+
+#define TAG_REFSPEC "refs/tags/*:refs/tags/*"
+extern const struct refspec_item *tag_refspec;
+
+struct refspec_item {
+	unsigned force : 1;
+	unsigned pattern : 1;
+	unsigned matching : 1;
+	unsigned exact_sha1 : 1;
+
+	char *src;
+	char *dst;
+};
+
+#define REFSPEC_FETCH 1
+#define REFSPEC_PUSH 0
+
+#define REFSPEC_INIT_FETCH { .fetch = REFSPEC_FETCH }
+#define REFSPEC_INIT_PUSH { .fetch = REFSPEC_PUSH }
+
+struct refspec {
+	struct refspec_item *items;
+	int alloc;
+	int nr;
+
+	const char **raw;
+	int raw_alloc;
+	int raw_nr;
+
+	int fetch;
+};
+
+void refspec_item_init(struct refspec_item *item, const char *refspec, int fetch);
+void refspec_item_clear(struct refspec_item *item);
+void refspec_init(struct refspec *rs, int fetch);
+void refspec_append(struct refspec *rs, const char *refspec);
+void refspec_appendn(struct refspec *rs, const char **refspecs, int nr);
+void refspec_clear(struct refspec *rs);
+
+int valid_fetch_refspec(const char *refspec);
+
+struct argv_array;
+/*
+ * Determine what <prefix> values to pass to the peer in ref-prefix lines
+ * (see Documentation/technical/protocol-v2.txt).
+ */
+void refspec_ref_prefixes(const struct refspec *rs,
+			  struct argv_array *ref_prefixes);
+
+#endif /* REFSPEC_H */
diff --git a/remote-curl.c b/remote-curl.c
index 8d2ffaf..99b0bed 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -1,6 +1,7 @@
 #include "cache.h"
 #include "config.h"
 #include "remote.h"
+#include "connect.h"
 #include "strbuf.h"
 #include "walker.h"
 #include "http.h"
@@ -13,6 +14,7 @@
 #include "credential.h"
 #include "sha1-array.h"
 #include "send-pack.h"
+#include "protocol.h"
 #include "quote.h"
 
 static struct remote *remote;
@@ -184,12 +186,13 @@
 }
 
 struct discovery {
-	const char *service;
+	char *service;
 	char *buf_alloc;
 	char *buf;
 	size_t len;
 	struct ref *refs;
 	struct oid_array shallow;
+	enum protocol_version version;
 	unsigned proto_git : 1;
 };
 static struct discovery *last_discovery;
@@ -197,8 +200,31 @@
 static struct ref *parse_git_refs(struct discovery *heads, int for_push)
 {
 	struct ref *list = NULL;
-	get_remote_heads(-1, heads->buf, heads->len, &list,
-			 for_push ? REF_NORMAL : 0, NULL, &heads->shallow);
+	struct packet_reader reader;
+
+	packet_reader_init(&reader, -1, heads->buf, heads->len,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_GENTLE_ON_EOF);
+
+	heads->version = discover_version(&reader);
+	switch (heads->version) {
+	case protocol_v2:
+		/*
+		 * Do nothing.  This isn't a list of refs but rather a
+		 * capability advertisement.  Client would have run
+		 * 'stateless-connect' so we'll dump this capability listing
+		 * and let them request the refs themselves.
+		 */
+		break;
+	case protocol_v1:
+	case protocol_v0:
+		get_remote_heads(&reader, &list, for_push ? REF_NORMAL : 0,
+				 NULL, &heads->shallow);
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
+	}
+
 	return list;
 }
 
@@ -259,6 +285,7 @@
 		free(d->shallow.oid);
 		free(d->buf_alloc);
 		free_refs(d->refs);
+		free(d->service);
 		free(d);
 	}
 }
@@ -290,6 +317,19 @@
 	return 0;
 }
 
+static int get_protocol_http_header(enum protocol_version version,
+				    struct strbuf *header)
+{
+	if (version > 0) {
+		strbuf_addf(header, GIT_PROTOCOL_HEADER ": version=%d",
+			    version);
+
+		return 1;
+	}
+
+	return 0;
+}
+
 static struct discovery *discover_refs(const char *service, int for_push)
 {
 	struct strbuf exp = STRBUF_INIT;
@@ -298,9 +338,12 @@
 	struct strbuf buffer = STRBUF_INIT;
 	struct strbuf refs_url = STRBUF_INIT;
 	struct strbuf effective_url = STRBUF_INIT;
+	struct strbuf protocol_header = STRBUF_INIT;
+	struct string_list extra_headers = STRING_LIST_INIT_DUP;
 	struct discovery *last = last_discovery;
 	int http_ret, maybe_smart = 0;
 	struct http_get_options http_options;
+	enum protocol_version version = get_protocol_version_config();
 
 	if (last && !strcmp(service, last->service))
 		return last;
@@ -317,11 +360,24 @@
 		strbuf_addf(&refs_url, "service=%s", service);
 	}
 
+	/*
+	 * NEEDSWORK: If we are trying to use protocol v2 and we are planning
+	 * to perform a push, then fallback to v0 since the client doesn't know
+	 * how to push yet using v2.
+	 */
+	if (version == protocol_v2 && !strcmp("git-receive-pack", service))
+		version = protocol_v0;
+
+	/* Add the extra Git-Protocol header */
+	if (get_protocol_http_header(version, &protocol_header))
+		string_list_append(&extra_headers, protocol_header.buf);
+
 	memset(&http_options, 0, sizeof(http_options));
 	http_options.content_type = &type;
 	http_options.charset = &charset;
 	http_options.effective_url = &effective_url;
 	http_options.base_url = &url;
+	http_options.extra_headers = &extra_headers;
 	http_options.initial_request = 1;
 	http_options.no_cache = 1;
 	http_options.keep_error = 1;
@@ -345,7 +401,7 @@
 		warning(_("redirecting to %s"), url.buf);
 
 	last= xcalloc(1, sizeof(*last_discovery));
-	last->service = service;
+	last->service = xstrdup(service);
 	last->buf_alloc = strbuf_detach(&buffer, &last->len);
 	last->buf = last->buf_alloc;
 
@@ -377,6 +433,9 @@
 			;
 
 		last->proto_git = 1;
+	} else if (maybe_smart &&
+		   last->len > 5 && starts_with(last->buf + 4, "version 2")) {
+		last->proto_git = 1;
 	}
 
 	if (last->proto_git)
@@ -390,6 +449,8 @@
 	strbuf_release(&charset);
 	strbuf_release(&effective_url);
 	strbuf_release(&buffer);
+	strbuf_release(&protocol_header);
+	string_list_clear(&extra_headers, 0);
 	last_discovery = last;
 	return last;
 }
@@ -426,6 +487,7 @@
 	char *service_url;
 	char *hdr_content_type;
 	char *hdr_accept;
+	char *protocol_header;
 	char *buf;
 	size_t alloc;
 	size_t len;
@@ -612,13 +674,17 @@
 	headers = curl_slist_append(headers, needs_100_continue ?
 		"Expect: 100-continue" : "Expect:");
 
+	/* Add the extra Git-Protocol header */
+	if (rpc->protocol_header)
+		headers = curl_slist_append(headers, rpc->protocol_header);
+
 retry:
 	slot = get_active_slot();
 
 	curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
 	curl_easy_setopt(slot->curl, CURLOPT_POST, 1);
 	curl_easy_setopt(slot->curl, CURLOPT_URL, rpc->service_url);
-	curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "gzip");
+	curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "");
 
 	if (large_request) {
 		/* The request body is large and the size cannot be predicted.
@@ -752,6 +818,11 @@
 	strbuf_addf(&buf, "Accept: application/x-%s-result", svc);
 	rpc->hdr_accept = strbuf_detach(&buf, NULL);
 
+	if (get_protocol_http_header(heads->version, &buf))
+		rpc->protocol_header = strbuf_detach(&buf, NULL);
+	else
+		rpc->protocol_header = NULL;
+
 	while (!err) {
 		int n = packet_read(rpc->out, NULL, NULL, rpc->buf, rpc->alloc, 0);
 		if (!n)
@@ -779,6 +850,7 @@
 	free(rpc->service_url);
 	free(rpc->hdr_content_type);
 	free(rpc->hdr_accept);
+	free(rpc->protocol_header);
 	free(rpc->buf);
 	strbuf_release(&buf);
 	return err;
@@ -797,9 +869,6 @@
 		targets[i] = xstrdup(oid_to_hex(&to_fetch[i]->old_oid));
 
 	walker = get_http_walker(url.buf);
-	walker->get_all = 1;
-	walker->get_tree = 1;
-	walker->get_history = 1;
 	walker->get_verbosely = options.verbosity >= 3;
 	walker->get_recover = 0;
 	ret = walker_fetch(walker, nr_heads, targets, NULL, NULL);
@@ -1056,6 +1125,203 @@
 	free(specs);
 }
 
+/*
+ * Used to represent the state of a connection to an HTTP server when
+ * communicating using git's wire-protocol version 2.
+ */
+struct proxy_state {
+	char *service_name;
+	char *service_url;
+	struct curl_slist *headers;
+	struct strbuf request_buffer;
+	int in;
+	int out;
+	struct packet_reader reader;
+	size_t pos;
+	int seen_flush;
+};
+
+static void proxy_state_init(struct proxy_state *p, const char *service_name,
+			     enum protocol_version version)
+{
+	struct strbuf buf = STRBUF_INIT;
+
+	memset(p, 0, sizeof(*p));
+	p->service_name = xstrdup(service_name);
+
+	p->in = 0;
+	p->out = 1;
+	strbuf_init(&p->request_buffer, 0);
+
+	strbuf_addf(&buf, "%s%s", url.buf, p->service_name);
+	p->service_url = strbuf_detach(&buf, NULL);
+
+	p->headers = http_copy_default_headers();
+
+	strbuf_addf(&buf, "Content-Type: application/x-%s-request", p->service_name);
+	p->headers = curl_slist_append(p->headers, buf.buf);
+	strbuf_reset(&buf);
+
+	strbuf_addf(&buf, "Accept: application/x-%s-result", p->service_name);
+	p->headers = curl_slist_append(p->headers, buf.buf);
+	strbuf_reset(&buf);
+
+	p->headers = curl_slist_append(p->headers, "Transfer-Encoding: chunked");
+
+	/* Add the Git-Protocol header */
+	if (get_protocol_http_header(version, &buf))
+		p->headers = curl_slist_append(p->headers, buf.buf);
+
+	packet_reader_init(&p->reader, p->in, NULL, 0,
+			   PACKET_READ_GENTLE_ON_EOF);
+
+	strbuf_release(&buf);
+}
+
+static void proxy_state_clear(struct proxy_state *p)
+{
+	free(p->service_name);
+	free(p->service_url);
+	curl_slist_free_all(p->headers);
+	strbuf_release(&p->request_buffer);
+}
+
+/*
+ * CURLOPT_READFUNCTION callback function.
+ * Attempts to copy over a single packet-line at a time into the
+ * curl provided buffer.
+ */
+static size_t proxy_in(char *buffer, size_t eltsize,
+		       size_t nmemb, void *userdata)
+{
+	size_t max;
+	struct proxy_state *p = userdata;
+	size_t avail = p->request_buffer.len - p->pos;
+
+
+	if (eltsize != 1)
+		BUG("curl read callback called with size = %"PRIuMAX" != 1",
+		    (uintmax_t)eltsize);
+	max = nmemb;
+
+	if (!avail) {
+		if (p->seen_flush) {
+			p->seen_flush = 0;
+			return 0;
+		}
+
+		strbuf_reset(&p->request_buffer);
+		switch (packet_reader_read(&p->reader)) {
+		case PACKET_READ_EOF:
+			die("unexpected EOF when reading from parent process");
+		case PACKET_READ_NORMAL:
+			packet_buf_write_len(&p->request_buffer, p->reader.line,
+					     p->reader.pktlen);
+			break;
+		case PACKET_READ_DELIM:
+			packet_buf_delim(&p->request_buffer);
+			break;
+		case PACKET_READ_FLUSH:
+			packet_buf_flush(&p->request_buffer);
+			p->seen_flush = 1;
+			break;
+		}
+		p->pos = 0;
+		avail = p->request_buffer.len;
+	}
+
+	if (max < avail)
+		avail = max;
+	memcpy(buffer, p->request_buffer.buf + p->pos, avail);
+	p->pos += avail;
+	return avail;
+}
+
+static size_t proxy_out(char *buffer, size_t eltsize,
+			size_t nmemb, void *userdata)
+{
+	size_t size;
+	struct proxy_state *p = userdata;
+
+	if (eltsize != 1)
+		BUG("curl read callback called with size = %"PRIuMAX" != 1",
+		    (uintmax_t)eltsize);
+	size = nmemb;
+
+	write_or_die(p->out, buffer, size);
+	return size;
+}
+
+/* Issues a request to the HTTP server configured in `p` */
+static int proxy_request(struct proxy_state *p)
+{
+	struct active_request_slot *slot;
+
+	slot = get_active_slot();
+
+	curl_easy_setopt(slot->curl, CURLOPT_ENCODING, "");
+	curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
+	curl_easy_setopt(slot->curl, CURLOPT_POST, 1);
+	curl_easy_setopt(slot->curl, CURLOPT_URL, p->service_url);
+	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, p->headers);
+
+	/* Setup function to read request from client */
+	curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, proxy_in);
+	curl_easy_setopt(slot->curl, CURLOPT_READDATA, p);
+
+	/* Setup function to write server response to client */
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, proxy_out);
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, p);
+
+	if (run_slot(slot, NULL) != HTTP_OK)
+		return -1;
+
+	return 0;
+}
+
+static int stateless_connect(const char *service_name)
+{
+	struct discovery *discover;
+	struct proxy_state p;
+
+	/*
+	 * Run the info/refs request and see if the server supports protocol
+	 * v2.  If and only if the server supports v2 can we successfully
+	 * establish a stateless connection, otherwise we need to tell the
+	 * client to fallback to using other transport helper functions to
+	 * complete their request.
+	 */
+	discover = discover_refs(service_name, 0);
+	if (discover->version != protocol_v2) {
+		printf("fallback\n");
+		fflush(stdout);
+		return -1;
+	} else {
+		/* Stateless Connection established */
+		printf("\n");
+		fflush(stdout);
+	}
+
+	proxy_state_init(&p, service_name, discover->version);
+
+	/*
+	 * Dump the capability listing that we got from the server earlier
+	 * during the info/refs request.
+	 */
+	write_or_die(p.out, discover->buf, discover->len);
+
+	/* Peek the next packet line.  Until we see EOF keep sending POSTs */
+	while (packet_reader_peek(&p.reader) != PACKET_READ_EOF) {
+		if (proxy_request(&p)) {
+			/* We would have an err here */
+			break;
+		}
+	}
+
+	proxy_state_clear(&p);
+	return 0;
+}
+
 int cmd_main(int argc, const char **argv)
 {
 	struct strbuf buf = STRBUF_INIT;
@@ -1124,12 +1390,16 @@
 			fflush(stdout);
 
 		} else if (!strcmp(buf.buf, "capabilities")) {
+			printf("stateless-connect\n");
 			printf("fetch\n");
 			printf("option\n");
 			printf("push\n");
 			printf("check-connectivity\n");
 			printf("\n");
 			fflush(stdout);
+		} else if (skip_prefix(buf.buf, "stateless-connect ", &arg)) {
+			if (!stateless_connect(arg))
+				break;
 		} else {
 			error("remote-curl: unknown command '%s' from git", buf.buf);
 			return 1;
diff --git a/remote.c b/remote.c
index 91eb010..abe80c1 100644
--- a/remote.c
+++ b/remote.c
@@ -2,6 +2,7 @@
 #include "config.h"
 #include "remote.h"
 #include "refs.h"
+#include "refspec.h"
 #include "commit.h"
 #include "diff.h"
 #include "revision.h"
@@ -13,18 +14,6 @@
 
 enum map_direction { FROM_SRC, FROM_DST };
 
-static struct refspec s_tag_refspec = {
-	0,
-	1,
-	0,
-	0,
-	"refs/tags/*",
-	"refs/tags/*"
-};
-
-/* See TAG_REFSPEC for the string version */
-const struct refspec *tag_refspec = &s_tag_refspec;
-
 struct counted_string {
 	size_t len;
 	const char *s;
@@ -88,33 +77,6 @@
 	return xstrfmt("%s%s", r->rewrite[longest_i]->base, url + longest->len);
 }
 
-static void add_push_refspec(struct remote *remote, const char *ref)
-{
-	ALLOC_GROW(remote->push_refspec,
-		   remote->push_refspec_nr + 1,
-		   remote->push_refspec_alloc);
-	remote->push_refspec[remote->push_refspec_nr++] = ref;
-}
-
-static void add_fetch_refspec(struct remote *remote, const char *ref)
-{
-	ALLOC_GROW(remote->fetch_refspec,
-		   remote->fetch_refspec_nr + 1,
-		   remote->fetch_refspec_alloc);
-	remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
-}
-
-void add_prune_tags_to_fetch_refspec(struct remote *remote)
-{
-	int nr = remote->fetch_refspec_nr;
-	int bufsize = nr  + 1;
-	int size = sizeof(struct refspec);
-
-	remote->fetch = xrealloc(remote->fetch, size  * bufsize);
-	memcpy(&remote->fetch[nr], tag_refspec, size);
-	add_fetch_refspec(remote, xstrdup(TAG_REFSPEC));
-}
-
 static void add_url(struct remote *remote, const char *url)
 {
 	ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
@@ -186,9 +148,12 @@
 	ret = xcalloc(1, sizeof(struct remote));
 	ret->prune = -1;  /* unspecified */
 	ret->prune_tags = -1;  /* unspecified */
+	ret->name = xstrndup(name, len);
+	refspec_init(&ret->push, REFSPEC_PUSH);
+	refspec_init(&ret->fetch, REFSPEC_FETCH);
+
 	ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 	remotes[remotes_nr++] = ret;
-	ret->name = xstrndup(name, len);
 
 	hashmap_entry_init(ret, lookup_entry.hash);
 	replaced = hashmap_put(&remotes_hash, ret);
@@ -286,9 +251,9 @@
 		if (skip_prefix(buf.buf, "URL:", &v))
 			add_url_alias(remote, xstrdup(skip_spaces(v)));
 		else if (skip_prefix(buf.buf, "Push:", &v))
-			add_push_refspec(remote, xstrdup(skip_spaces(v)));
+			refspec_append(&remote->push, skip_spaces(v));
 		else if (skip_prefix(buf.buf, "Pull:", &v))
-			add_fetch_refspec(remote, xstrdup(skip_spaces(v)));
+			refspec_append(&remote->fetch, skip_spaces(v));
 	}
 	strbuf_release(&buf);
 	fclose(f);
@@ -327,15 +292,19 @@
 		frag = "master";
 
 	add_url_alias(remote, strbuf_detach(&buf, NULL));
-	add_fetch_refspec(remote, xstrfmt("refs/heads/%s:refs/heads/%s",
-					  frag, remote->name));
+	strbuf_addf(&buf, "refs/heads/%s:refs/heads/%s",
+		    frag, remote->name);
+	refspec_append(&remote->fetch, buf.buf);
 
 	/*
 	 * Cogito compatible push: push current HEAD to remote #branch
 	 * (master if missing)
 	 */
-	add_push_refspec(remote, xstrfmt("HEAD:refs/heads/%s", frag));
+	strbuf_reset(&buf);
+	strbuf_addf(&buf, "HEAD:refs/heads/%s", frag);
+	refspec_append(&remote->push, buf.buf);
 	remote->fetch_tags = 1; /* always auto-follow */
+	strbuf_release(&buf);
 }
 
 static int handle_config(const char *key, const char *value, void *cb)
@@ -420,12 +389,14 @@
 		const char *v;
 		if (git_config_string(&v, key, value))
 			return -1;
-		add_push_refspec(remote, v);
+		refspec_append(&remote->push, v);
+		free((char *)v);
 	} else if (!strcmp(subkey, "fetch")) {
 		const char *v;
 		if (git_config_string(&v, key, value))
 			return -1;
-		add_fetch_refspec(remote, v);
+		refspec_append(&remote->fetch, v);
+		free((char *)v);
 	} else if (!strcmp(subkey, "receivepack")) {
 		const char *v;
 		if (git_config_string(&v, key, value))
@@ -499,158 +470,6 @@
 	alias_all_urls();
 }
 
-static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
-{
-	int i;
-	struct refspec *rs = xcalloc(nr_refspec, sizeof(*rs));
-
-	for (i = 0; i < nr_refspec; i++) {
-		size_t llen;
-		int is_glob;
-		const char *lhs, *rhs;
-		int flags;
-
-		is_glob = 0;
-
-		lhs = refspec[i];
-		if (*lhs == '+') {
-			rs[i].force = 1;
-			lhs++;
-		}
-
-		rhs = strrchr(lhs, ':');
-
-		/*
-		 * Before going on, special case ":" (or "+:") as a refspec
-		 * for pushing matching refs.
-		 */
-		if (!fetch && rhs == lhs && rhs[1] == '\0') {
-			rs[i].matching = 1;
-			continue;
-		}
-
-		if (rhs) {
-			size_t rlen = strlen(++rhs);
-			is_glob = (1 <= rlen && strchr(rhs, '*'));
-			rs[i].dst = xstrndup(rhs, rlen);
-		}
-
-		llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
-		if (1 <= llen && memchr(lhs, '*', llen)) {
-			if ((rhs && !is_glob) || (!rhs && fetch))
-				goto invalid;
-			is_glob = 1;
-		} else if (rhs && is_glob) {
-			goto invalid;
-		}
-
-		rs[i].pattern = is_glob;
-		rs[i].src = xstrndup(lhs, llen);
-		flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
-
-		if (fetch) {
-			struct object_id unused;
-
-			/* LHS */
-			if (!*rs[i].src)
-				; /* empty is ok; it means "HEAD" */
-			else if (llen == GIT_SHA1_HEXSZ && !get_oid_hex(rs[i].src, &unused))
-				rs[i].exact_sha1 = 1; /* ok */
-			else if (!check_refname_format(rs[i].src, flags))
-				; /* valid looking ref is ok */
-			else
-				goto invalid;
-			/* RHS */
-			if (!rs[i].dst)
-				; /* missing is ok; it is the same as empty */
-			else if (!*rs[i].dst)
-				; /* empty is ok; it means "do not store" */
-			else if (!check_refname_format(rs[i].dst, flags))
-				; /* valid looking ref is ok */
-			else
-				goto invalid;
-		} else {
-			/*
-			 * LHS
-			 * - empty is allowed; it means delete.
-			 * - when wildcarded, it must be a valid looking ref.
-			 * - otherwise, it must be an extended SHA-1, but
-			 *   there is no existing way to validate this.
-			 */
-			if (!*rs[i].src)
-				; /* empty is ok */
-			else if (is_glob) {
-				if (check_refname_format(rs[i].src, flags))
-					goto invalid;
-			}
-			else
-				; /* anything goes, for now */
-			/*
-			 * RHS
-			 * - missing is allowed, but LHS then must be a
-			 *   valid looking ref.
-			 * - empty is not allowed.
-			 * - otherwise it must be a valid looking ref.
-			 */
-			if (!rs[i].dst) {
-				if (check_refname_format(rs[i].src, flags))
-					goto invalid;
-			} else if (!*rs[i].dst) {
-				goto invalid;
-			} else {
-				if (check_refname_format(rs[i].dst, flags))
-					goto invalid;
-			}
-		}
-	}
-	return rs;
-
- invalid:
-	if (verify) {
-		/*
-		 * nr_refspec must be greater than zero and i must be valid
-		 * since it is only possible to reach this point from within
-		 * the for loop above.
-		 */
-		free_refspec(i+1, rs);
-		return NULL;
-	}
-	die("Invalid refspec '%s'", refspec[i]);
-}
-
-int valid_fetch_refspec(const char *fetch_refspec_str)
-{
-	struct refspec *refspec;
-
-	refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
-	free_refspec(1, refspec);
-	return !!refspec;
-}
-
-struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
-{
-	return parse_refspec_internal(nr_refspec, refspec, 1, 0);
-}
-
-struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
-{
-	return parse_refspec_internal(nr_refspec, refspec, 0, 0);
-}
-
-void free_refspec(int nr_refspec, struct refspec *refspec)
-{
-	int i;
-
-	if (!refspec)
-		return;
-
-	for (i = 0; i < nr_refspec; i++) {
-		free(refspec[i].src);
-		free(refspec[i].dst);
-	}
-	free(refspec);
-}
-
 static int valid_remote_nick(const char *name)
 {
 	if (!name[0] || is_dot_or_dotdot(name))
@@ -705,9 +524,8 @@
 				pushremote_for_branch(branch, NULL);
 			struct remote *remote = remote_get(remote_name);
 
-			if (remote && remote->push_refspec_nr &&
-			    (dst = apply_refspecs(remote->push,
-						  remote->push_refspec_nr,
+			if (remote && remote->push.nr &&
+			    (dst = apply_refspecs(&remote->push,
 						  branch->refname))) {
 				if (explicit)
 					*explicit = 1;
@@ -744,8 +562,6 @@
 		add_url_alias(ret, name);
 	if (!valid_remote(ret))
 		return NULL;
-	ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
-	ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 	return ret;
 }
 
@@ -776,12 +592,6 @@
 		struct remote *r = remotes[i];
 		if (!r)
 			continue;
-		if (!r->fetch)
-			r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
-						       r->fetch_refspec);
-		if (!r->push)
-			r->push = parse_push_refspec(r->push_refspec_nr,
-						     r->push_refspec);
 		result = fn(r, priv);
 	}
 	return result;
@@ -887,7 +697,9 @@
 	return ret;
 }
 
-static void query_refspecs_multiple(struct refspec *refs, int ref_count, struct refspec *query, struct string_list *results)
+static void query_refspecs_multiple(struct refspec *rs,
+				    struct refspec_item *query,
+				    struct string_list *results)
 {
 	int i;
 	int find_src = !query->src;
@@ -895,8 +707,8 @@
 	if (find_src && !query->dst)
 		error("query_refspecs_multiple: need either src or dst");
 
-	for (i = 0; i < ref_count; i++) {
-		struct refspec *refspec = &refs[i];
+	for (i = 0; i < rs->nr; i++) {
+		struct refspec_item *refspec = &rs->items[i];
 		const char *key = find_src ? refspec->dst : refspec->src;
 		const char *value = find_src ? refspec->src : refspec->dst;
 		const char *needle = find_src ? query->dst : query->src;
@@ -913,7 +725,7 @@
 	}
 }
 
-int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
+int query_refspecs(struct refspec *rs, struct refspec_item *query)
 {
 	int i;
 	int find_src = !query->src;
@@ -923,8 +735,8 @@
 	if (find_src && !query->dst)
 		return error("query_refspecs: need either src or dst");
 
-	for (i = 0; i < ref_count; i++) {
-		struct refspec *refspec = &refs[i];
+	for (i = 0; i < rs->nr; i++) {
+		struct refspec_item *refspec = &rs->items[i];
 		const char *key = find_src ? refspec->dst : refspec->src;
 		const char *value = find_src ? refspec->src : refspec->dst;
 
@@ -944,23 +756,22 @@
 	return -1;
 }
 
-char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
-		     const char *name)
+char *apply_refspecs(struct refspec *rs, const char *name)
 {
-	struct refspec query;
+	struct refspec_item query;
 
-	memset(&query, 0, sizeof(struct refspec));
+	memset(&query, 0, sizeof(struct refspec_item));
 	query.src = (char *)name;
 
-	if (query_refspecs(refspecs, nr_refspec, &query))
+	if (query_refspecs(rs, &query))
 		return NULL;
 
 	return query.dst;
 }
 
-int remote_find_tracking(struct remote *remote, struct refspec *refspec)
+int remote_find_tracking(struct remote *remote, struct refspec_item *refspec)
 {
-	return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
+	return query_refspecs(&remote->fetch, refspec);
 }
 
 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
@@ -1167,7 +978,7 @@
 }
 
 static int match_explicit_lhs(struct ref *src,
-			      struct refspec *rs,
+			      struct refspec_item *rs,
 			      struct ref **match,
 			      int *allocated_match)
 {
@@ -1193,7 +1004,7 @@
 
 static int match_explicit(struct ref *src, struct ref *dst,
 			  struct ref ***dst_tail,
-			  struct refspec *rs)
+			  struct refspec_item *rs)
 {
 	struct ref *matched_src, *matched_dst;
 	int allocated_src;
@@ -1262,36 +1073,37 @@
 }
 
 static int match_explicit_refs(struct ref *src, struct ref *dst,
-			       struct ref ***dst_tail, struct refspec *rs,
-			       int rs_nr)
+			       struct ref ***dst_tail, struct refspec *rs)
 {
 	int i, errs;
-	for (i = errs = 0; i < rs_nr; i++)
-		errs += match_explicit(src, dst, dst_tail, &rs[i]);
+	for (i = errs = 0; i < rs->nr; i++)
+		errs += match_explicit(src, dst, dst_tail, &rs->items[i]);
 	return errs;
 }
 
-static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
-		int send_mirror, int direction, const struct refspec **ret_pat)
+static char *get_ref_match(const struct refspec *rs, const struct ref *ref,
+			   int send_mirror, int direction,
+			   const struct refspec_item **ret_pat)
 {
-	const struct refspec *pat;
+	const struct refspec_item *pat;
 	char *name;
 	int i;
 	int matching_refs = -1;
-	for (i = 0; i < rs_nr; i++) {
-		if (rs[i].matching &&
-		    (matching_refs == -1 || rs[i].force)) {
+	for (i = 0; i < rs->nr; i++) {
+		const struct refspec_item *item = &rs->items[i];
+		if (item->matching &&
+		    (matching_refs == -1 || item->force)) {
 			matching_refs = i;
 			continue;
 		}
 
-		if (rs[i].pattern) {
-			const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
+		if (item->pattern) {
+			const char *dst_side = item->dst ? item->dst : item->src;
 			int match;
 			if (direction == FROM_SRC)
-				match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
+				match = match_name_with_pattern(item->src, ref->name, dst_side, &name);
 			else
-				match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
+				match = match_name_with_pattern(dst_side, ref->name, item->src, &name);
 			if (match) {
 				matching_refs = i;
 				break;
@@ -1301,7 +1113,7 @@
 	if (matching_refs == -1)
 		return NULL;
 
-	pat = rs + matching_refs;
+	pat = &rs->items[matching_refs];
 	if (pat->matching) {
 		/*
 		 * "matching refs"; traditionally we pushed everything
@@ -1376,7 +1188,7 @@
 			continue; /* not a tag */
 		if (string_list_has_string(&dst_tag, ref->name))
 			continue; /* they already have it */
-		if (oid_object_info(&ref->new_oid, NULL) != OBJ_TAG)
+		if (oid_object_info(the_repository, &ref->new_oid, NULL) != OBJ_TAG)
 			continue; /* be conservative */
 		item = string_list_append(&src_tag, ref->name);
 		item->util = ref;
@@ -1443,22 +1255,20 @@
  * but we can catch some errors early before even talking to the
  * remote side.
  */
-int check_push_refs(struct ref *src, int nr_refspec, const char **refspec_names)
+int check_push_refs(struct ref *src, struct refspec *rs)
 {
-	struct refspec *refspec = parse_push_refspec(nr_refspec, refspec_names);
 	int ret = 0;
 	int i;
 
-	for (i = 0; i < nr_refspec; i++) {
-		struct refspec *rs = refspec + i;
+	for (i = 0; i < rs->nr; i++) {
+		struct refspec_item *item = &rs->items[i];
 
-		if (rs->pattern || rs->matching)
+		if (item->pattern || item->matching)
 			continue;
 
-		ret |= match_explicit_lhs(src, rs, NULL, NULL);
+		ret |= match_explicit_lhs(src, item, NULL, NULL);
 	}
 
-	free_refspec(nr_refspec, refspec);
 	return ret;
 }
 
@@ -1471,32 +1281,29 @@
  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
  */
 int match_push_refs(struct ref *src, struct ref **dst,
-		    int nr_refspec, const char **refspec, int flags)
+		    struct refspec *rs, int flags)
 {
-	struct refspec *rs;
 	int send_all = flags & MATCH_REFS_ALL;
 	int send_mirror = flags & MATCH_REFS_MIRROR;
 	int send_prune = flags & MATCH_REFS_PRUNE;
 	int errs;
-	static const char *default_refspec[] = { ":", NULL };
 	struct ref *ref, **dst_tail = tail_ref(dst);
 	struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
 
-	if (!nr_refspec) {
-		nr_refspec = 1;
-		refspec = default_refspec;
-	}
-	rs = parse_push_refspec(nr_refspec, (const char **) refspec);
-	errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
+	/* If no refspec is provided, use the default ":" */
+	if (!rs->nr)
+		refspec_append(rs, ":");
+
+	errs = match_explicit_refs(src, *dst, &dst_tail, rs);
 
 	/* pick the remainder */
 	for (ref = src; ref; ref = ref->next) {
 		struct string_list_item *dst_item;
 		struct ref *dst_peer;
-		const struct refspec *pat = NULL;
+		const struct refspec_item *pat = NULL;
 		char *dst_name;
 
-		dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
+		dst_name = get_ref_match(rs, ref, send_mirror, FROM_SRC, &pat);
 		if (!dst_name)
 			continue;
 
@@ -1545,7 +1352,7 @@
 				/* We're already sending something to this ref. */
 				continue;
 
-			src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
+			src_name = get_ref_match(rs, ref, send_mirror, FROM_DST, NULL);
 			if (src_name) {
 				if (!src_ref_index.nr)
 					prepare_ref_index(&src_ref_index, src);
@@ -1557,6 +1364,7 @@
 		}
 		string_list_clear(&src_ref_index, 0);
 	}
+
 	if (errs)
 		return -1;
 	return 0;
@@ -1753,7 +1561,7 @@
 {
 	char *ret;
 
-	ret = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
+	ret = apply_refspecs(&remote->fetch, refname);
 	if (!ret)
 		return error_buf(err,
 				 _("push destination '%s' on remote '%s' has no local tracking branch"),
@@ -1771,12 +1579,11 @@
 				 _("branch '%s' has no remote for pushing"),
 				 branch->name);
 
-	if (remote->push_refspec_nr) {
+	if (remote->push.nr) {
 		char *dst;
 		const char *ret;
 
-		dst = apply_refspecs(remote->push, remote->push_refspec_nr,
-				     branch->refname);
+		dst = apply_refspecs(&remote->push, branch->refname);
 		if (!dst)
 			return error_buf(err,
 					 _("push refspecs for '%s' do not include '%s'"),
@@ -1819,7 +1626,7 @@
 		}
 	}
 
-	die("BUG: unhandled push situation");
+	BUG("unhandled push situation");
 }
 
 const char *branch_get_push(struct branch *branch, struct strbuf *err)
@@ -1849,7 +1656,7 @@
  * local symbolic ref.
  */
 static struct ref *get_expanded_map(const struct ref *remote_refs,
-				    const struct refspec *refspec)
+				    const struct refspec_item *refspec)
 {
 	const struct ref *ref;
 	struct ref *ret = NULL;
@@ -1914,7 +1721,7 @@
 }
 
 int get_fetch_map(const struct ref *remote_refs,
-		  const struct refspec *refspec,
+		  const struct refspec_item *refspec,
 		  struct ref ***tail,
 		  int missing_ok)
 {
@@ -2252,8 +2059,7 @@
 struct stale_heads_info {
 	struct string_list *ref_names;
 	struct ref **stale_refs_tail;
-	struct refspec *refs;
-	int ref_count;
+	struct refspec *rs;
 };
 
 static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
@@ -2261,12 +2067,12 @@
 {
 	struct stale_heads_info *info = cb_data;
 	struct string_list matches = STRING_LIST_INIT_DUP;
-	struct refspec query;
+	struct refspec_item query;
 	int i, stale = 1;
-	memset(&query, 0, sizeof(struct refspec));
+	memset(&query, 0, sizeof(struct refspec_item));
 	query.dst = (char *)refname;
 
-	query_refspecs_multiple(info->refs, info->ref_count, &query, &matches);
+	query_refspecs_multiple(info->rs, &query, &matches);
 	if (matches.nr == 0)
 		goto clean_exit; /* No matches */
 
@@ -2294,7 +2100,7 @@
 	return 0;
 }
 
-struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
+struct ref *get_stale_heads(struct refspec *rs, struct ref *fetch_map)
 {
 	struct ref *ref, *stale_refs = NULL;
 	struct string_list ref_names = STRING_LIST_INIT_NODUP;
@@ -2302,8 +2108,7 @@
 
 	info.ref_names = &ref_names;
 	info.stale_refs_tail = &stale_refs;
-	info.refs = refs;
-	info.ref_count = ref_count;
+	info.rs = rs;
 	for (ref = fetch_map; ref; ref = ref->next)
 		string_list_append(&ref_names, ref->name);
 	string_list_sort(&ref_names);
@@ -2387,7 +2192,7 @@
 {
 	char *dst;
 
-	dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
+	dst = apply_refspecs(&remote->fetch, refname);
 	if (!dst)
 		return -1; /* no tracking ref for refname at remote */
 	if (read_ref(dst, oid))
diff --git a/remote.h b/remote.h
index f09c019..45ecc6c 100644
--- a/remote.h
+++ b/remote.h
@@ -3,6 +3,7 @@
 
 #include "parse-options.h"
 #include "hashmap.h"
+#include "refspec.h"
 
 enum {
 	REMOTE_UNCONFIGURED = 0,
@@ -27,15 +28,9 @@
 	int pushurl_nr;
 	int pushurl_alloc;
 
-	const char **push_refspec;
-	struct refspec *push;
-	int push_refspec_nr;
-	int push_refspec_alloc;
+	struct refspec push;
 
-	const char **fetch_refspec;
-	struct refspec *fetch;
-	int fetch_refspec_nr;
-	int fetch_refspec_alloc;
+	struct refspec fetch;
 
 	/*
 	 * -1 to never fetch tags
@@ -68,18 +63,6 @@
 
 int remote_has_url(struct remote *remote, const char *url);
 
-struct refspec {
-	unsigned force : 1;
-	unsigned pattern : 1;
-	unsigned matching : 1;
-	unsigned exact_sha1 : 1;
-
-	char *src;
-	char *dst;
-};
-
-extern const struct refspec *tag_refspec;
-
 struct ref {
 	struct ref *next;
 	struct object_id old_oid;
@@ -151,10 +134,19 @@
 void free_refs(struct ref *ref);
 
 struct oid_array;
-extern struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
+struct packet_reader;
+struct argv_array;
+struct string_list;
+extern struct ref **get_remote_heads(struct packet_reader *reader,
 				     struct ref **list, unsigned int flags,
 				     struct oid_array *extra_have,
-				     struct oid_array *shallow);
+				     struct oid_array *shallow_points);
+
+/* Used for protocol v2 in order to retrieve refs from a remote */
+extern struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
+				    struct ref **list, int for_push,
+				    const struct argv_array *ref_prefixes,
+				    const struct string_list *server_options);
 
 int resolve_remote_symref(struct ref *ref, struct ref *list);
 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid);
@@ -168,19 +160,12 @@
  */
 struct ref *ref_remove_duplicates(struct ref *ref_map);
 
-int valid_fetch_refspec(const char *refspec);
-struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec);
-extern struct refspec *parse_push_refspec(int nr_refspec, const char **refspec);
+int query_refspecs(struct refspec *rs, struct refspec_item *query);
+char *apply_refspecs(struct refspec *rs, const char *name);
 
-void free_refspec(int nr_refspec, struct refspec *refspec);
-
-extern int query_refspecs(struct refspec *specs, int nr, struct refspec *query);
-char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
-		     const char *name);
-
-int check_push_refs(struct ref *src, int nr_refspec, const char **refspec);
+int check_push_refs(struct ref *src, struct refspec *rs);
 int match_push_refs(struct ref *src, struct ref **dst,
-		    int nr_refspec, const char **refspec, int all);
+		    struct refspec *rs, int flags);
 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
 	int force_update);
 
@@ -196,7 +181,7 @@
  * missing_ok is usually false, but when we are adding branch.$name.merge
  * it is Ok if the branch is not at the remote anymore.
  */
-int get_fetch_map(const struct ref *remote_refs, const struct refspec *refspec,
+int get_fetch_map(const struct ref *remote_refs, const struct refspec_item *refspec,
 		  struct ref ***tail, int missing_ok);
 
 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name);
@@ -204,7 +189,7 @@
 /*
  * For the given remote, reads the refspec's src and sets the other fields.
  */
-int remote_find_tracking(struct remote *remote, struct refspec *refspec);
+int remote_find_tracking(struct remote *remote, struct refspec_item *refspec);
 
 struct branch {
 	const char *name;
@@ -214,7 +199,7 @@
 	const char *pushremote_name;
 
 	const char **merge_name;
-	struct refspec **merge;
+	struct refspec_item **merge;
 	int merge_nr;
 	int merge_alloc;
 
@@ -283,7 +268,7 @@
 			      int all);
 
 /* Return refs which no longer exist on remote */
-struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map);
+struct ref *get_stale_heads(struct refspec *rs, struct ref *fetch_map);
 
 /*
  * Compare-and-swap
@@ -306,8 +291,4 @@
 extern int is_empty_cas(const struct push_cas_option *);
 void apply_push_cas(struct push_cas_option *, struct remote *, struct ref *);
 
-#define TAG_REFSPEC "refs/tags/*:refs/tags/*"
-
-void add_prune_tags_to_fetch_refspec(struct remote *remote);
-
 #endif
diff --git a/replace-object.c b/replace-object.c
index 3363573..801b5c1 100644
--- a/replace-object.c
+++ b/replace-object.c
@@ -1,55 +1,11 @@
 #include "cache.h"
-#include "sha1-lookup.h"
+#include "oidmap.h"
+#include "object-store.h"
+#include "replace-object.h"
 #include "refs.h"
+#include "repository.h"
 #include "commit.h"
 
-/*
- * An array of replacements.  The array is kept sorted by the original
- * sha1.
- */
-static struct replace_object {
-	struct object_id original;
-	struct object_id replacement;
-} **replace_object;
-
-static int replace_object_alloc, replace_object_nr;
-
-static const unsigned char *replace_sha1_access(size_t index, void *table)
-{
-	struct replace_object **replace = table;
-	return replace[index]->original.hash;
-}
-
-static int replace_object_pos(const unsigned char *sha1)
-{
-	return sha1_pos(sha1, replace_object, replace_object_nr,
-			replace_sha1_access);
-}
-
-static int register_replace_object(struct replace_object *replace,
-				   int ignore_dups)
-{
-	int pos = replace_object_pos(replace->original.hash);
-
-	if (0 <= pos) {
-		if (ignore_dups)
-			free(replace);
-		else {
-			free(replace_object[pos]);
-			replace_object[pos] = replace;
-		}
-		return 1;
-	}
-	pos = -pos - 1;
-	ALLOC_GROW(replace_object, replace_object_nr + 1, replace_object_alloc);
-	replace_object_nr++;
-	if (pos < replace_object_nr)
-		MOVE_ARRAY(replace_object + pos + 1, replace_object + pos,
-			   replace_object_nr - pos - 1);
-	replace_object[pos] = replace;
-	return 0;
-}
-
 static int register_replace_ref(const char *refname,
 				const struct object_id *oid,
 				int flag, void *cb_data)
@@ -59,7 +15,7 @@
 	const char *hash = slash ? slash + 1 : refname;
 	struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
 
-	if (get_oid_hex(hash, &repl_obj->original)) {
+	if (get_oid_hex(hash, &repl_obj->original.oid)) {
 		free(repl_obj);
 		warning("bad replace ref name: %s", refname);
 		return 0;
@@ -69,23 +25,22 @@
 	oidcpy(&repl_obj->replacement, oid);
 
 	/* Register new object */
-	if (register_replace_object(repl_obj, 1))
+	if (oidmap_put(the_repository->objects->replace_map, repl_obj))
 		die("duplicate replace ref: %s", refname);
 
 	return 0;
 }
 
-static void prepare_replace_object(void)
+static void prepare_replace_object(struct repository *r)
 {
-	static int replace_object_prepared;
-
-	if (replace_object_prepared)
+	if (r->objects->replace_map)
 		return;
 
-	for_each_replace_ref(register_replace_ref, NULL);
-	replace_object_prepared = 1;
-	if (!replace_object_nr)
-		check_replace_refs = 0;
+	r->objects->replace_map =
+		xmalloc(sizeof(*r->objects->replace_map));
+	oidmap_init(r->objects->replace_map, 0);
+
+	for_each_replace_ref(r, register_replace_ref, NULL);
 }
 
 /* We allow "recursive" replacement. Only within reason, though */
@@ -98,23 +53,21 @@
  * permanently-allocated value.  This function always respects replace
  * references, regardless of the value of check_replace_refs.
  */
-const struct object_id *do_lookup_replace_object(const struct object_id *oid)
+const struct object_id *do_lookup_replace_object(struct repository *r,
+						 const struct object_id *oid)
 {
-	int pos, depth = MAXREPLACEDEPTH;
+	int depth = MAXREPLACEDEPTH;
 	const struct object_id *cur = oid;
 
-	prepare_replace_object();
+	prepare_replace_object(r);
 
 	/* Try to recursively replace the object */
-	do {
-		if (--depth < 0)
-			die("replace depth too high for object %s",
-			    oid_to_hex(oid));
-
-		pos = replace_object_pos(cur->hash);
-		if (0 <= pos)
-			cur = &replace_object[pos]->replacement;
-	} while (0 <= pos);
-
-	return cur;
+	while (depth-- > 0) {
+		struct replace_object *repl_obj =
+			oidmap_get(r->objects->replace_map, cur);
+		if (!repl_obj)
+			return cur;
+		cur = &repl_obj->replacement;
+	}
+	die("replace depth too high for object %s", oid_to_hex(oid));
 }
diff --git a/replace-object.h b/replace-object.h
new file mode 100644
index 0000000..f996de3
--- /dev/null
+++ b/replace-object.h
@@ -0,0 +1,36 @@
+#ifndef REPLACE_OBJECT_H
+#define REPLACE_OBJECT_H
+
+#include "oidmap.h"
+#include "repository.h"
+#include "object-store.h"
+
+struct replace_object {
+	struct oidmap_entry original;
+	struct object_id replacement;
+};
+
+/*
+ * This internal function is only declared here for the benefit of
+ * lookup_replace_object().  Please do not call it directly.
+ */
+extern const struct object_id *do_lookup_replace_object(struct repository *r,
+							const struct object_id *oid);
+
+/*
+ * If object sha1 should be replaced, return the replacement object's
+ * name (replaced recursively, if necessary).  The return value is
+ * either sha1 or a pointer to a permanently-allocated value.  When
+ * object replacement is suppressed, always return sha1.
+ */
+static inline const struct object_id *lookup_replace_object(struct repository *r,
+							    const struct object_id *oid)
+{
+	if (!check_replace_refs ||
+	    (r->objects->replace_map &&
+	     r->objects->replace_map->map.tablesize == 0))
+		return oid;
+	return do_lookup_replace_object(r, oid);
+}
+
+#endif /* REPLACE_OBJECT_H */
diff --git a/repository.c b/repository.c
index a4848c1..02fe884 100644
--- a/repository.c
+++ b/repository.c
@@ -135,9 +135,9 @@
  * Initialize 'repo' based on the provided 'gitdir'.
  * Return 0 upon success and a non-zero value upon failure.
  */
-static int repo_init(struct repository *repo,
-		     const char *gitdir,
-		     const char *worktree)
+int repo_init(struct repository *repo,
+	      const char *gitdir,
+	      const char *worktree)
 {
 	struct repository_format format;
 	memset(repo, 0, sizeof(*repo));
@@ -176,7 +176,7 @@
 	struct strbuf worktree = STRBUF_INIT;
 	int ret = 0;
 
-	sub = submodule_from_cache(superproject, &null_oid, path);
+	sub = submodule_from_path(superproject, &null_oid, path);
 	if (!sub) {
 		ret = -1;
 		goto out;
@@ -238,7 +238,8 @@
 
 	if (repo->index) {
 		discard_index(repo->index);
-		FREE_AND_NULL(repo->index);
+		if (repo->index != &the_index)
+			FREE_AND_NULL(repo->index);
 	}
 }
 
diff --git a/repository.h b/repository.h
index 09df94a..f2646f0 100644
--- a/repository.h
+++ b/repository.h
@@ -26,6 +26,9 @@
 	 */
 	struct raw_object_store *objects;
 
+	/* The store in which the refs are held. */
+	struct ref_store *refs;
+
 	/*
 	 * Path to the repository's graft file.
 	 * Cannot be NULL after initialization.
@@ -97,6 +100,9 @@
 extern void repo_set_worktree(struct repository *repo, const char *path);
 extern void repo_set_hash_algo(struct repository *repo, int algo);
 extern void initialize_the_repository(void);
+extern int repo_init(struct repository *r,
+		     const char *gitdir,
+		     const char *worktree);
 extern int repo_submodule_init(struct repository *submodule,
 			       struct repository *superproject,
 			       const char *path);
diff --git a/rerere.c b/rerere.c
index 18cae2d..e0862e2 100644
--- a/rerere.c
+++ b/rerere.c
@@ -703,10 +703,9 @@
 	return ret;
 }
 
-static struct lock_file index_lock;
-
 static void update_paths(struct string_list *update)
 {
+	struct lock_file index_lock = LOCK_INIT;
 	int i;
 
 	hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
diff --git a/resolve-undo.c b/resolve-undo.c
index aed95b4..fc5b3b8 100644
--- a/resolve-undo.c
+++ b/resolve-undo.c
@@ -90,7 +90,7 @@
 				continue;
 			if (size < rawsz)
 				goto error;
-			memcpy(ui->oid[i].hash, (const unsigned char *)data, rawsz);
+			oidread(&ui->oid[i], (const unsigned char *)data);
 			size -= rawsz;
 			data += rawsz;
 		}
diff --git a/revision.c b/revision.c
index b42c836..40fd91f 100644
--- a/revision.c
+++ b/revision.c
@@ -6,6 +6,7 @@
 #include "diff.h"
 #include "refs.h"
 #include "revision.h"
+#include "repository.h"
 #include "graph.h"
 #include "grep.h"
 #include "reflog-walk.h"
@@ -51,12 +52,9 @@
 {
 	struct tree_desc desc;
 	struct name_entry entry;
-	struct object *obj = &tree->object;
 
-	if (!has_object_file(&obj->oid))
+	if (parse_tree_gently(tree, 1) < 0)
 		return;
-	if (parse_tree(tree) < 0)
-		die("bad tree %s", oid_to_hex(&obj->oid));
 
 	init_tree_desc(&desc, tree->buffer, tree->size);
 	while (tree_entry(&desc, &entry)) {
@@ -94,50 +92,63 @@
 	mark_tree_contents_uninteresting(tree);
 }
 
+struct commit_stack {
+	struct commit **items;
+	size_t nr, alloc;
+};
+#define COMMIT_STACK_INIT { NULL, 0, 0 }
+
+static void commit_stack_push(struct commit_stack *stack, struct commit *commit)
+{
+	ALLOC_GROW(stack->items, stack->nr + 1, stack->alloc);
+	stack->items[stack->nr++] = commit;
+}
+
+static struct commit *commit_stack_pop(struct commit_stack *stack)
+{
+	return stack->nr ? stack->items[--stack->nr] : NULL;
+}
+
+static void commit_stack_clear(struct commit_stack *stack)
+{
+	FREE_AND_NULL(stack->items);
+	stack->nr = stack->alloc = 0;
+}
+
+static void mark_one_parent_uninteresting(struct commit *commit,
+					  struct commit_stack *pending)
+{
+	struct commit_list *l;
+
+	if (commit->object.flags & UNINTERESTING)
+		return;
+	commit->object.flags |= UNINTERESTING;
+
+	/*
+	 * Normally we haven't parsed the parent
+	 * yet, so we won't have a parent of a parent
+	 * here. However, it may turn out that we've
+	 * reached this commit some other way (where it
+	 * wasn't uninteresting), in which case we need
+	 * to mark its parents recursively too..
+	 */
+	for (l = commit->parents; l; l = l->next)
+		commit_stack_push(pending, l->item);
+}
+
 void mark_parents_uninteresting(struct commit *commit)
 {
-	struct commit_list *parents = NULL, *l;
+	struct commit_stack pending = COMMIT_STACK_INIT;
+	struct commit_list *l;
 
 	for (l = commit->parents; l; l = l->next)
-		commit_list_insert(l->item, &parents);
+		mark_one_parent_uninteresting(l->item, &pending);
 
-	while (parents) {
-		struct commit *commit = pop_commit(&parents);
+	while (pending.nr > 0)
+		mark_one_parent_uninteresting(commit_stack_pop(&pending),
+					      &pending);
 
-		while (commit) {
-			/*
-			 * A missing commit is ok iff its parent is marked
-			 * uninteresting.
-			 *
-			 * We just mark such a thing parsed, so that when
-			 * it is popped next time around, we won't be trying
-			 * to parse it and get an error.
-			 */
-			if (!commit->object.parsed &&
-			    !has_object_file(&commit->object.oid))
-				commit->object.parsed = 1;
-
-			if (commit->object.flags & UNINTERESTING)
-				break;
-
-			commit->object.flags |= UNINTERESTING;
-
-			/*
-			 * Normally we haven't parsed the parent
-			 * yet, so we won't have a parent of a parent
-			 * here. However, it may turn out that we've
-			 * reached this commit some other way (where it
-			 * wasn't uninteresting), in which case we need
-			 * to mark its parents recursively too..
-			 */
-			if (!commit->parents)
-				break;
-
-			for (l = commit->parents->next; l; l = l->next)
-				commit_list_insert(l->item, &parents);
-			commit = commit->parents->item;
-		}
-	}
+	commit_stack_clear(&pending);
 }
 
 static void add_pending_object_with_path(struct rev_info *revs,
@@ -440,8 +451,8 @@
 static int rev_compare_tree(struct rev_info *revs,
 			    struct commit *parent, struct commit *commit)
 {
-	struct tree *t1 = parent->tree;
-	struct tree *t2 = commit->tree;
+	struct tree *t1 = get_commit_tree(parent);
+	struct tree *t2 = get_commit_tree(commit);
 
 	if (!t1)
 		return REV_TREE_NEW;
@@ -477,7 +488,7 @@
 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
 {
 	int retval;
-	struct tree *t1 = commit->tree;
+	struct tree *t1 = get_commit_tree(commit);
 
 	if (!t1)
 		return 0;
@@ -615,7 +626,7 @@
 	if (!revs->prune)
 		return;
 
-	if (!commit->tree)
+	if (!get_commit_tree(commit))
 		return;
 
 	if (!commit->parents) {
@@ -1285,7 +1296,7 @@
 
 	cb.all_revs = revs;
 	cb.all_flags = flags;
-	cb.refs = get_main_ref_store();
+	cb.refs = get_main_ref_store(the_repository);
 	for_each_reflog(handle_one_reflog, &cb);
 
 	if (!revs->single_worktree)
@@ -1751,6 +1762,7 @@
 	const char *arg = argv[0];
 	const char *optarg;
 	int argcount;
+	const unsigned hexsz = the_hash_algo->hexsz;
 
 	/* pseudo revision arguments */
 	if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
@@ -2038,8 +2050,8 @@
 		revs->abbrev = strtoul(optarg, NULL, 10);
 		if (revs->abbrev < MINIMUM_ABBREV)
 			revs->abbrev = MINIMUM_ABBREV;
-		else if (revs->abbrev > 40)
-			revs->abbrev = 40;
+		else if (revs->abbrev > hexsz)
+			revs->abbrev = hexsz;
 	} else if (!strcmp(arg, "--abbrev-commit")) {
 		revs->abbrev_commit = 1;
 		revs->abbrev_commit_given = 1;
@@ -2107,7 +2119,7 @@
 		revs->ignore_missing = 1;
 	} else if (!strcmp(arg, "--exclude-promisor-objects")) {
 		if (fetch_if_missing)
-			die("BUG: exclude_promisor_objects can only be used when fetch_if_missing is 0");
+			BUG("exclude_promisor_objects can only be used when fetch_if_missing is 0");
 		revs->exclude_promisor_objects = 1;
 	} else {
 		int opts = diff_opt_parse(&revs->diffopt, argv, argc, revs->prefix);
@@ -2173,10 +2185,10 @@
 		 * supported right now, so stick to single worktree.
 		 */
 		if (!revs->single_worktree)
-			die("BUG: --single-worktree cannot be used together with submodule");
+			BUG("--single-worktree cannot be used together with submodule");
 		refs = get_submodule_ref_store(submodule);
 	} else
-		refs = get_main_ref_store();
+		refs = get_main_ref_store(the_repository);
 
 	/*
 	 * NOTE!
@@ -3086,7 +3098,7 @@
 {
 	if (commit->object.flags & SHOWN)
 		return commit_ignore;
-	if (revs->unpacked && has_sha1_pack(commit->object.oid.hash))
+	if (revs->unpacked && has_object_pack(&commit->object.oid))
 		return commit_ignore;
 	if (commit->object.flags & UNINTERESTING)
 		return commit_ignore;
diff --git a/run-command.c b/run-command.c
index 12c94c1..84b883c 100644
--- a/run-command.c
+++ b/run-command.c
@@ -245,7 +245,7 @@
 static const char **prepare_shell_cmd(struct argv_array *out, const char **argv)
 {
 	if (!argv[0])
-		die("BUG: shell command is empty");
+		BUG("shell command is empty");
 
 	if (strcspn(argv[0], "|&;<>()$`\\\"' \t\n*?[#~=%") != strlen(argv[0])) {
 #ifndef GIT_WINDOWS_NATIVE
@@ -383,7 +383,7 @@
 static void prepare_cmd(struct argv_array *out, const struct child_process *cmd)
 {
 	if (!cmd->argv[0])
-		die("BUG: command is empty");
+		BUG("command is empty");
 
 	/*
 	 * Add SHELL_PATH so in the event exec fails with ENOEXEC we can
@@ -471,15 +471,12 @@
 	sigset_t old;
 };
 
-#ifndef NO_PTHREADS
-static void bug_die(int err, const char *msg)
-{
-	if (err) {
-		errno = err;
-		die_errno("BUG: %s", msg);
-	}
-}
-#endif
+#define CHECK_BUG(err, msg) \
+	do { \
+		int e = (err); \
+		if (e) \
+			BUG("%s: %s", msg, strerror(e)); \
+	} while(0)
 
 static void atfork_prepare(struct atfork_state *as)
 {
@@ -491,9 +488,9 @@
 	if (sigprocmask(SIG_SETMASK, &all, &as->old))
 		die_errno("sigprocmask");
 #else
-	bug_die(pthread_sigmask(SIG_SETMASK, &all, &as->old),
+	CHECK_BUG(pthread_sigmask(SIG_SETMASK, &all, &as->old),
 		"blocking all signals");
-	bug_die(pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &as->cs),
+	CHECK_BUG(pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &as->cs),
 		"disabling cancellation");
 #endif
 }
@@ -504,9 +501,9 @@
 	if (sigprocmask(SIG_SETMASK, &as->old, NULL))
 		die_errno("sigprocmask");
 #else
-	bug_die(pthread_setcancelstate(as->cs, NULL),
+	CHECK_BUG(pthread_setcancelstate(as->cs, NULL),
 		"re-enabling cancellation");
-	bug_die(pthread_sigmask(SIG_SETMASK, &as->old, NULL),
+	CHECK_BUG(pthread_sigmask(SIG_SETMASK, &as->old, NULL),
 		"restoring signal mask");
 #endif
 }
@@ -967,7 +964,7 @@
 	int code;
 
 	if (cmd->out < 0 || cmd->err < 0)
-		die("BUG: run_command with a pipe can cause deadlock");
+		BUG("run_command with a pipe can cause deadlock");
 
 	code = start_command(cmd);
 	if (code)
@@ -1557,7 +1554,7 @@
 
 	pp->data = data;
 	if (!get_next_task)
-		die("BUG: you need to specify a get_next_task function");
+		BUG("you need to specify a get_next_task function");
 	pp->get_next_task = get_next_task;
 
 	pp->start_failure = start_failure ? start_failure : default_start_failure;
@@ -1619,7 +1616,7 @@
 		if (pp->children[i].state == GIT_CP_FREE)
 			break;
 	if (i == pp->max_processes)
-		die("BUG: bookkeeping is hard");
+		BUG("bookkeeping is hard");
 
 	code = pp->get_next_task(&pp->children[i].process,
 				 &pp->children[i].err,
diff --git a/sequencer.c b/sequencer.c
index 017adbe..cca9680 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -27,6 +27,7 @@
 #include "worktree.h"
 #include "oidmap.h"
 #include "oidset.h"
+#include "alias.h"
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
@@ -78,13 +79,6 @@
  * previous commit and from the first squash/fixup commit are written
  * to it. The commit message for each subsequent squash/fixup commit
  * is appended to the file as it is processed.
- *
- * The first line of the file is of the form
- *     # This is a combination of $count commits.
- * where $count is the number of commits whose messages have been
- * written to the file so far (including the initial "pick" commit).
- * Each time that a commit message is processed, this line is read and
- * updated. It is deleted just before the combined commit is made.
  */
 static GIT_PATH_FUNC(rebase_path_squash_msg, "rebase-merge/message-squash")
 /*
@@ -96,6 +90,11 @@
  */
 static GIT_PATH_FUNC(rebase_path_fixup_msg, "rebase-merge/message-fixup")
 /*
+ * This file contains the list fixup/squash commands that have been
+ * accumulated into message-fixup or message-squash so far.
+ */
+static GIT_PATH_FUNC(rebase_path_current_fixups, "rebase-merge/current-fixups")
+/*
  * A script to set the GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
  * GIT_AUTHOR_DATE that will be used for the commit that is currently
  * being rebased.
@@ -126,6 +125,12 @@
 	"rebase-merge/rewritten-pending")
 
 /*
+ * The path of the file containig the OID of the "squash onto" commit, i.e.
+ * the dummy commit used for `reset [new root]`.
+ */
+static GIT_PATH_FUNC(rebase_path_squash_onto, "rebase-merge/squash-onto")
+
+/*
  * The path of the file listing refs that need to be deleted after the rebase
  * finishes. This is used by the `label` command to record the need for cleanup.
  */
@@ -279,6 +284,7 @@
 	for (i = 0; i < opts->xopts_nr; i++)
 		free(opts->xopts[i]);
 	free(opts->xopts);
+	strbuf_release(&opts->current_fixups);
 
 	strbuf_reset(&buf);
 	strbuf_addstr(&buf, get_dir(opts));
@@ -470,7 +476,8 @@
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, "HEAD",
-				   to, unborn ? &null_oid : from,
+				   to, unborn && !is_rebase_i(opts) ?
+				   &null_oid : from,
 				   0, sb.buf, &err) ||
 	    ref_transaction_commit(transaction, &err)) {
 		ref_transaction_free(transaction);
@@ -529,8 +536,8 @@
 	o.show_rename_progress = 1;
 
 	head_tree = parse_tree_indirect(head);
-	next_tree = next ? next->tree : empty_tree();
-	base_tree = base ? base->tree : empty_tree();
+	next_tree = next ? get_commit_tree(next) : empty_tree();
+	base_tree = base ? get_commit_tree(base) : empty_tree();
 
 	for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 		parse_merge_opt(&o, *xopt);
@@ -562,9 +569,23 @@
 	return !clean;
 }
 
+static struct object_id *get_cache_tree_oid(void)
+{
+	if (!active_cache_tree)
+		active_cache_tree = cache_tree();
+
+	if (!cache_tree_fully_valid(active_cache_tree))
+		if (cache_tree_update(&the_index, 0)) {
+			error(_("unable to update cache tree"));
+			return NULL;
+		}
+
+	return &active_cache_tree->oid;
+}
+
 static int is_index_unchanged(void)
 {
-	struct object_id head_oid;
+	struct object_id head_oid, *cache_tree_oid;
 	struct commit *head_commit;
 
 	if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
@@ -583,15 +604,10 @@
 	if (parse_commit(head_commit))
 		return -1;
 
-	if (!active_cache_tree)
-		active_cache_tree = cache_tree();
+	if (!(cache_tree_oid = get_cache_tree_oid()))
+		return -1;
 
-	if (!cache_tree_fully_valid(active_cache_tree))
-		if (cache_tree_update(&the_index, 0))
-			return error(_("unable to update cache tree"));
-
-	return !oidcmp(&active_cache_tree->oid,
-		       &head_commit->tree->object.oid);
+	return !oidcmp(cache_tree_oid, get_commit_tree_oid(head_commit));
 }
 
 static int write_author_script(const char *message)
@@ -683,6 +699,52 @@
 	return NULL;
 }
 
+/* Read author-script and return an ident line (author <email> timestamp) */
+static const char *read_author_ident(struct strbuf *buf)
+{
+	const char *keys[] = {
+		"GIT_AUTHOR_NAME=", "GIT_AUTHOR_EMAIL=", "GIT_AUTHOR_DATE="
+	};
+	char *in, *out, *eol;
+	int i = 0, len;
+
+	if (strbuf_read_file(buf, rebase_path_author_script(), 256) <= 0)
+		return NULL;
+
+	/* dequote values and construct ident line in-place */
+	for (in = out = buf->buf; i < 3 && in - buf->buf < buf->len; i++) {
+		if (!skip_prefix(in, keys[i], (const char **)&in)) {
+			warning("could not parse '%s' (looking for '%s'",
+				rebase_path_author_script(), keys[i]);
+			return NULL;
+		}
+
+		eol = strchrnul(in, '\n');
+		*eol = '\0';
+		sq_dequote(in);
+		len = strlen(in);
+
+		if (i > 0) /* separate values by spaces */
+			*(out++) = ' ';
+		if (i == 1) /* email needs to be surrounded by <...> */
+			*(out++) = '<';
+		memmove(out, in, len);
+		out += len;
+		if (i == 1) /* email needs to be surrounded by <...> */
+			*(out++) = '>';
+		in = eol + 1;
+	}
+
+	if (i < 3) {
+		warning("could not parse '%s' (looking for '%s')",
+			rebase_path_author_script(), keys[i]);
+		return NULL;
+	}
+
+	buf->len = out - buf->buf;
+	return buf->buf;
+}
+
 static const char staged_changes_advice[] =
 N_("you have staged changes in your working tree\n"
 "If these changes are meant to be squashed into the previous commit, run:\n"
@@ -702,6 +764,7 @@
 #define AMEND_MSG   (1<<2)
 #define CLEANUP_MSG (1<<3)
 #define VERIFY_MSG  (1<<4)
+#define CREATE_ROOT_COMMIT (1<<5)
 
 /*
  * If we are cherry-pick, and if the merge did not result in
@@ -721,6 +784,40 @@
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	const char *value;
 
+	if (flags & CREATE_ROOT_COMMIT) {
+		struct strbuf msg = STRBUF_INIT, script = STRBUF_INIT;
+		const char *author = is_rebase_i(opts) ?
+			read_author_ident(&script) : NULL;
+		struct object_id root_commit, *cache_tree_oid;
+		int res = 0;
+
+		if (!defmsg)
+			BUG("root commit without message");
+
+		if (!(cache_tree_oid = get_cache_tree_oid()))
+			res = -1;
+
+		if (!res)
+			res = strbuf_read_file(&msg, defmsg, 0);
+
+		if (res <= 0)
+			res = error_errno(_("could not read '%s'"), defmsg);
+		else
+			res = commit_tree(msg.buf, msg.len, cache_tree_oid,
+					  NULL, &root_commit, author,
+					  opts->gpg_sign);
+
+		strbuf_release(&msg);
+		strbuf_release(&script);
+		if (!res) {
+			update_ref(NULL, "CHERRY_PICK_HEAD", &root_commit, NULL,
+				   REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR);
+			res = update_ref(NULL, "HEAD", &root_commit, NULL, 0,
+					 UPDATE_REFS_MSG_ON_ERR);
+		}
+		return res < 0 ? error(_("writing root commit")) : 0;
+	}
+
 	cmd.git_cmd = 1;
 
 	if (is_rebase_i(opts)) {
@@ -747,6 +844,8 @@
 		argv_array_pushf(&cmd.args, "-S%s", opts->gpg_sign);
 	if (defmsg)
 		argv_array_pushl(&cmd.args, "-F", defmsg, NULL);
+	else if (!(flags & EDIT_MSG))
+		argv_array_pushl(&cmd.args, "-C", "HEAD", NULL);
 	if ((flags & CLEANUP_MSG))
 		argv_array_push(&cmd.args, "--cleanup=strip");
 	if ((flags & EDIT_MSG))
@@ -1148,8 +1247,8 @@
 	}
 
 	if (!(flags & ALLOW_EMPTY) && !oidcmp(current_head ?
-					      &current_head->tree->object.oid :
-					      &empty_tree_oid, &tree)) {
+					      get_commit_tree_oid(current_head) :
+					      the_hash_algo->empty_tree, &tree)) {
 		res = 1; /* run 'git commit' to display error message */
 		goto out;
 	}
@@ -1178,6 +1277,8 @@
 		goto out;
 	}
 
+	reset_ident_date();
+
 	if (commit_tree_extended(msg->buf, msg->len, &tree, parents,
 				 oid, author, opts->gpg_sign, extra)) {
 		res = error(_("failed to write commit object"));
@@ -1207,7 +1308,8 @@
 {
 	int res = 1;
 
-	if (!(flags & EDIT_MSG) && !(flags & VERIFY_MSG)) {
+	if (!(flags & EDIT_MSG) && !(flags & VERIFY_MSG) &&
+	    !(flags & CREATE_ROOT_COMMIT)) {
 		struct object_id oid;
 		struct strbuf sb = STRBUF_INIT;
 
@@ -1246,12 +1348,12 @@
 		if (parse_commit(parent))
 			return error(_("could not parse parent commit %s"),
 				oid_to_hex(&parent->object.oid));
-		ptree_oid = &parent->tree->object.oid;
+		ptree_oid = get_commit_tree_oid(parent);
 	} else {
 		ptree_oid = the_hash_algo->empty_tree; /* commit is root */
 	}
 
-	return !oidcmp(ptree_oid, &commit->tree->object.oid);
+	return !oidcmp(ptree_oid, get_commit_tree_oid(commit));
 }
 
 /*
@@ -1360,38 +1462,43 @@
 	return command == TODO_FIXUP || command == TODO_SQUASH;
 }
 
+/* Does this command create a (non-merge) commit? */
+static int is_pick_or_similar(enum todo_command command)
+{
+	switch (command) {
+	case TODO_PICK:
+	case TODO_REVERT:
+	case TODO_EDIT:
+	case TODO_REWORD:
+	case TODO_FIXUP:
+	case TODO_SQUASH:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
 static int update_squash_messages(enum todo_command command,
 		struct commit *commit, struct replay_opts *opts)
 {
 	struct strbuf buf = STRBUF_INIT;
-	int count, res;
+	int res;
 	const char *message, *body;
 
-	if (file_exists(rebase_path_squash_msg())) {
+	if (opts->current_fixup_count > 0) {
 		struct strbuf header = STRBUF_INIT;
-		char *eol, *p;
+		char *eol;
 
-		if (strbuf_read_file(&buf, rebase_path_squash_msg(), 2048) <= 0)
+		if (strbuf_read_file(&buf, rebase_path_squash_msg(), 9) <= 0)
 			return error(_("could not read '%s'"),
 				rebase_path_squash_msg());
 
-		p = buf.buf + 1;
-		eol = strchrnul(buf.buf, '\n');
-		if (buf.buf[0] != comment_line_char ||
-		    (p += strcspn(p, "0123456789\n")) == eol)
-			return error(_("unexpected 1st line of squash message:"
-				       "\n\n\t%.*s"),
-				     (int)(eol - buf.buf), buf.buf);
-		count = strtol(p, NULL, 10);
-
-		if (count < 1)
-			return error(_("invalid 1st line of squash message:\n"
-				       "\n\t%.*s"),
-				     (int)(eol - buf.buf), buf.buf);
+		eol = buf.buf[0] != comment_line_char ?
+			buf.buf : strchrnul(buf.buf, '\n');
 
 		strbuf_addf(&header, "%c ", comment_line_char);
-		strbuf_addf(&header,
-			    _("This is a combination of %d commits."), ++count);
+		strbuf_addf(&header, _("This is a combination of %d commits."),
+			    opts->current_fixup_count + 2);
 		strbuf_splice(&buf, 0, eol - buf.buf, header.buf, header.len);
 		strbuf_release(&header);
 	} else {
@@ -1414,10 +1521,8 @@
 				     rebase_path_fixup_msg());
 		}
 
-		count = 2;
 		strbuf_addf(&buf, "%c ", comment_line_char);
-		strbuf_addf(&buf, _("This is a combination of %d commits."),
-			    count);
+		strbuf_addf(&buf, _("This is a combination of %d commits."), 2);
 		strbuf_addf(&buf, "\n%c ", comment_line_char);
 		strbuf_addstr(&buf, _("This is the 1st commit message:"));
 		strbuf_addstr(&buf, "\n\n");
@@ -1434,13 +1539,14 @@
 	if (command == TODO_SQUASH) {
 		unlink(rebase_path_fixup_msg());
 		strbuf_addf(&buf, "\n%c ", comment_line_char);
-		strbuf_addf(&buf, _("This is the commit message #%d:"), count);
+		strbuf_addf(&buf, _("This is the commit message #%d:"),
+			    ++opts->current_fixup_count);
 		strbuf_addstr(&buf, "\n\n");
 		strbuf_addstr(&buf, body);
 	} else if (command == TODO_FIXUP) {
 		strbuf_addf(&buf, "\n%c ", comment_line_char);
 		strbuf_addf(&buf, _("The commit message #%d will be skipped:"),
-			    count);
+			    ++opts->current_fixup_count);
 		strbuf_addstr(&buf, "\n\n");
 		strbuf_add_commented_lines(&buf, body, strlen(body));
 	} else
@@ -1449,6 +1555,17 @@
 
 	res = write_message(buf.buf, buf.len, rebase_path_squash_msg(), 0);
 	strbuf_release(&buf);
+
+	if (!res) {
+		strbuf_addf(&opts->current_fixups, "%s%s %s",
+			    opts->current_fixups.len ? "\n" : "",
+			    command_to_string(command),
+			    oid_to_hex(&commit->object.oid));
+		res = write_message(opts->current_fixups.buf,
+				    opts->current_fixups.len,
+				    rebase_path_current_fixups(), 0);
+	}
+
 	return res;
 }
 
@@ -1514,9 +1631,16 @@
 			return error(_("your index file is unmerged."));
 	} else {
 		unborn = get_oid("HEAD", &head);
-		if (unborn)
+		/* Do we want to generate a root commit? */
+		if (is_pick_or_similar(command) && opts->have_squash_onto &&
+		    !oidcmp(&head, &opts->squash_onto)) {
+			if (is_fixup(command))
+				return error(_("cannot fixup root commit"));
+			flags |= CREATE_ROOT_COMMIT;
+			unborn = 1;
+		} else if (unborn)
 			oidcpy(&head, the_hash_algo->empty_tree);
-		if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD",
+		if (index_differs_from(unborn ? empty_tree_oid_hex() : "HEAD",
 				       NULL, 0))
 			return error_dirty_index(opts);
 	}
@@ -1711,6 +1835,9 @@
 	if (!res && final_fixup) {
 		unlink(rebase_path_fixup_msg());
 		unlink(rebase_path_squash_msg());
+		unlink(rebase_path_current_fixups());
+		strbuf_reset(&opts->current_fixups);
+		opts->current_fixup_count = 0;
 	}
 
 leave:
@@ -2127,6 +2254,22 @@
 		read_strategy_opts(opts, &buf);
 		strbuf_release(&buf);
 
+		if (read_oneliner(&opts->current_fixups,
+				  rebase_path_current_fixups(), 1)) {
+			const char *p = opts->current_fixups.buf;
+			opts->current_fixup_count = 1;
+			while ((p = strchr(p, '\n'))) {
+				opts->current_fixup_count++;
+				p++;
+			}
+		}
+
+		if (read_oneliner(&buf, rebase_path_squash_onto(), 0)) {
+			if (get_oid_hex(buf.buf, &opts->squash_onto) < 0)
+				return error(_("unusable squash-onto"));
+			opts->have_squash_onto = 1;
+		}
+
 		return 0;
 	}
 
@@ -2471,10 +2614,9 @@
 static int error_failed_squash(struct commit *commit,
 	struct replay_opts *opts, int subject_len, const char *subject)
 {
-	if (rename(rebase_path_squash_msg(), rebase_path_message()))
-		return error(_("could not rename '%s' to '%s'"),
+	if (copy_file(rebase_path_message(), rebase_path_squash_msg(), 0666))
+		return error(_("could not copy '%s' to '%s'"),
 			rebase_path_squash_msg(), rebase_path_message());
-	unlink(rebase_path_fixup_msg());
 	unlink(git_path_merge_msg());
 	if (copy_file(git_path_merge_msg(), rebase_path_message(), 0666))
 		return error(_("could not copy '%s' to '%s'"),
@@ -2566,7 +2708,7 @@
 
 static int do_label(const char *name, int len)
 {
-	struct ref_store *refs = get_main_ref_store();
+	struct ref_store *refs = get_main_ref_store(the_repository);
 	struct ref_transaction *transaction;
 	struct strbuf ref_name = STRBUF_INIT, err = STRBUF_INIT;
 	struct strbuf msg = STRBUF_INIT;
@@ -2620,18 +2762,34 @@
 	if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
 		return -1;
 
-	/* Determine the length of the label */
-	for (i = 0; i < len; i++)
-		if (isspace(name[i]))
-			len = i;
+	if (len == 10 && !strncmp("[new root]", name, len)) {
+		if (!opts->have_squash_onto) {
+			const char *hex;
+			if (commit_tree("", 0, the_hash_algo->empty_tree,
+					NULL, &opts->squash_onto,
+					NULL, NULL))
+				return error(_("writing fake root commit"));
+			opts->have_squash_onto = 1;
+			hex = oid_to_hex(&opts->squash_onto);
+			if (write_message(hex, strlen(hex),
+					  rebase_path_squash_onto(), 0))
+				return error(_("writing squash-onto"));
+		}
+		oidcpy(&oid, &opts->squash_onto);
+	} else {
+		/* Determine the length of the label */
+		for (i = 0; i < len; i++)
+			if (isspace(name[i]))
+				len = i;
 
-	strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
-	if (get_oid(ref_name.buf, &oid) &&
-	    get_oid(ref_name.buf + strlen("refs/rewritten/"), &oid)) {
-		error(_("could not read '%s'"), ref_name.buf);
-		rollback_lock_file(&lock);
-		strbuf_release(&ref_name);
-		return -1;
+		strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
+		if (get_oid(ref_name.buf, &oid) &&
+		    get_oid(ref_name.buf + strlen("refs/rewritten/"), &oid)) {
+			error(_("could not read '%s'"), ref_name.buf);
+			rollback_lock_file(&lock);
+			strbuf_release(&ref_name);
+			return -1;
+		}
 	}
 
 	memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
@@ -2727,6 +2885,18 @@
 		goto leave_merge;
 	}
 
+	if (opts->have_squash_onto &&
+	    !oidcmp(&head_commit->object.oid, &opts->squash_onto)) {
+		/*
+		 * When the user tells us to "merge" something into a
+		 * "[new root]", let's simply fast-forward to the merge head.
+		 */
+		rollback_lock_file(&lock);
+		ret = fast_forward_to(&merge_commit->object.oid,
+				       &head_commit->object.oid, 0, opts);
+		goto leave_merge;
+	}
+
 	if (commit) {
 		const char *message = get_commit_buffer(commit, NULL);
 		const char *body;
@@ -3234,19 +3404,16 @@
 	return run_command_v_opt(argv, RUN_GIT_CMD);
 }
 
-static int commit_staged_changes(struct replay_opts *opts)
+static int commit_staged_changes(struct replay_opts *opts,
+				 struct todo_list *todo_list)
 {
 	unsigned int flags = ALLOW_EMPTY | EDIT_MSG;
+	unsigned int final_fixup = 0, is_clean;
 
 	if (has_unstaged_changes(1))
 		return error(_("cannot rebase: You have unstaged changes."));
-	if (!has_uncommitted_changes(0)) {
-		const char *cherry_pick_head = git_path_cherry_pick_head();
 
-		if (file_exists(cherry_pick_head) && unlink(cherry_pick_head))
-			return error(_("could not remove CHERRY_PICK_HEAD"));
-		return 0;
-	}
+	is_clean = !has_uncommitted_changes(0);
 
 	if (file_exists(rebase_path_amend())) {
 		struct strbuf rev = STRBUF_INIT;
@@ -3259,19 +3426,107 @@
 		if (get_oid_hex(rev.buf, &to_amend))
 			return error(_("invalid contents: '%s'"),
 				rebase_path_amend());
-		if (oidcmp(&head, &to_amend))
+		if (!is_clean && oidcmp(&head, &to_amend))
 			return error(_("\nYou have uncommitted changes in your "
 				       "working tree. Please, commit them\n"
 				       "first and then run 'git rebase "
 				       "--continue' again."));
+		/*
+		 * When skipping a failed fixup/squash, we need to edit the
+		 * commit message, the current fixup list and count, and if it
+		 * was the last fixup/squash in the chain, we need to clean up
+		 * the commit message and if there was a squash, let the user
+		 * edit it.
+		 */
+		if (is_clean && !oidcmp(&head, &to_amend) &&
+		    opts->current_fixup_count > 0 &&
+		    file_exists(rebase_path_stopped_sha())) {
+			const char *p = opts->current_fixups.buf;
+			int len = opts->current_fixups.len;
+
+			opts->current_fixup_count--;
+			if (!len)
+				BUG("Incorrect current_fixups:\n%s", p);
+			while (len && p[len - 1] != '\n')
+				len--;
+			strbuf_setlen(&opts->current_fixups, len);
+			if (write_message(p, len, rebase_path_current_fixups(),
+					  0) < 0)
+				return error(_("could not write file: '%s'"),
+					     rebase_path_current_fixups());
+
+			/*
+			 * If a fixup/squash in a fixup/squash chain failed, the
+			 * commit message is already correct, no need to commit
+			 * it again.
+			 *
+			 * Only if it is the final command in the fixup/squash
+			 * chain, and only if the chain is longer than a single
+			 * fixup/squash command (which was just skipped), do we
+			 * actually need to re-commit with a cleaned up commit
+			 * message.
+			 */
+			if (opts->current_fixup_count > 0 &&
+			    !is_fixup(peek_command(todo_list, 0))) {
+				final_fixup = 1;
+				/*
+				 * If there was not a single "squash" in the
+				 * chain, we only need to clean up the commit
+				 * message, no need to bother the user with
+				 * opening the commit message in the editor.
+				 */
+				if (!starts_with(p, "squash ") &&
+				    !strstr(p, "\nsquash "))
+					flags = (flags & ~EDIT_MSG) | CLEANUP_MSG;
+			} else if (is_fixup(peek_command(todo_list, 0))) {
+				/*
+				 * We need to update the squash message to skip
+				 * the latest commit message.
+				 */
+				struct commit *commit;
+				const char *path = rebase_path_squash_msg();
+
+				if (parse_head(&commit) ||
+				    !(p = get_commit_buffer(commit, NULL)) ||
+				    write_message(p, strlen(p), path, 0)) {
+					unuse_commit_buffer(commit, p);
+					return error(_("could not write file: "
+						       "'%s'"), path);
+				}
+				unuse_commit_buffer(commit, p);
+			}
+		}
 
 		strbuf_release(&rev);
 		flags |= AMEND_MSG;
 	}
 
-	if (run_git_commit(rebase_path_message(), opts, flags))
+	if (is_clean) {
+		const char *cherry_pick_head = git_path_cherry_pick_head();
+
+		if (file_exists(cherry_pick_head) && unlink(cherry_pick_head))
+			return error(_("could not remove CHERRY_PICK_HEAD"));
+		if (!final_fixup)
+			return 0;
+	}
+
+	if (run_git_commit(final_fixup ? NULL : rebase_path_message(),
+			   opts, flags))
 		return error(_("could not commit staged changes."));
 	unlink(rebase_path_amend());
+	if (final_fixup) {
+		unlink(rebase_path_fixup_msg());
+		unlink(rebase_path_squash_msg());
+	}
+	if (opts->current_fixup_count > 0) {
+		/*
+		 * Whether final fixup or not, we just cleaned up the commit
+		 * message...
+		 */
+		unlink(rebase_path_current_fixups());
+		strbuf_reset(&opts->current_fixups);
+		opts->current_fixup_count = 0;
+	}
 	return 0;
 }
 
@@ -3283,14 +3538,16 @@
 	if (read_and_refresh_cache(opts))
 		return -1;
 
+	if (read_populate_opts(opts))
+		return -1;
 	if (is_rebase_i(opts)) {
-		if (commit_staged_changes(opts))
+		if ((res = read_populate_todo(&todo_list, opts)))
+			goto release_todo_list;
+		if (commit_staged_changes(opts, &todo_list))
 			return -1;
 	} else if (!file_exists(get_todo_path(opts)))
 		return continue_single_pick();
-	if (read_populate_opts(opts))
-		return -1;
-	if ((res = read_populate_todo(&todo_list, opts)))
+	else if ((res = read_populate_todo(&todo_list, opts)))
 		goto release_todo_list;
 
 	if (!is_rebase_i(opts)) {
@@ -3349,7 +3606,8 @@
 
 		if (!get_oid(name, &oid)) {
 			if (!lookup_commit_reference_gently(&oid, 1)) {
-				enum object_type type = oid_object_info(&oid,
+				enum object_type type = oid_object_info(the_repository,
+									&oid,
 									NULL);
 				return error(_("%s: can't cherry-pick a %s"),
 					name, type_name(type));
@@ -3748,7 +4006,8 @@
 		}
 
 		if (!commit)
-			fprintf(out, "%s onto\n", cmd_reset);
+			fprintf(out, "%s %s\n", cmd_reset,
+				rebase_cousins ? "onto" : "[new root]");
 		else {
 			const char *to = NULL;
 
diff --git a/sequencer.h b/sequencer.h
index d9570d9..c5787c6 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -44,10 +44,18 @@
 	char **xopts;
 	size_t xopts_nr, xopts_alloc;
 
+	/* Used by fixup/squash */
+	struct strbuf current_fixups;
+	int current_fixup_count;
+
+	/* placeholder commit for -i --root */
+	struct object_id squash_onto;
+	int have_squash_onto;
+
 	/* Only used by REPLAY_NONE */
 	struct rev_info *revs;
 };
-#define REPLAY_OPTS_INIT { -1 }
+#define REPLAY_OPTS_INIT { .action = -1, .current_fixups = STRBUF_INIT }
 
 /* Call this to setup defaults before parsing command line options */
 void sequencer_init_config(struct replay_opts *opts);
diff --git a/serve.c b/serve.c
new file mode 100644
index 0000000..bda085f
--- /dev/null
+++ b/serve.c
@@ -0,0 +1,258 @@
+#include "cache.h"
+#include "repository.h"
+#include "config.h"
+#include "pkt-line.h"
+#include "version.h"
+#include "argv-array.h"
+#include "ls-refs.h"
+#include "serve.h"
+#include "upload-pack.h"
+
+static int always_advertise(struct repository *r,
+			    struct strbuf *value)
+{
+	return 1;
+}
+
+static int agent_advertise(struct repository *r,
+			   struct strbuf *value)
+{
+	if (value)
+		strbuf_addstr(value, git_user_agent_sanitized());
+	return 1;
+}
+
+struct protocol_capability {
+	/*
+	 * The name of the capability.  The server uses this name when
+	 * advertising this capability, and the client uses this name to
+	 * specify this capability.
+	 */
+	const char *name;
+
+	/*
+	 * Function queried to see if a capability should be advertised.
+	 * Optionally a value can be specified by adding it to 'value'.
+	 * If a value is added to 'value', the server will advertise this
+	 * capability as "<name>=<value>" instead of "<name>".
+	 */
+	int (*advertise)(struct repository *r, struct strbuf *value);
+
+	/*
+	 * Function called when a client requests the capability as a command.
+	 * The function will be provided the capabilities requested via 'keys'
+	 * as well as a struct packet_reader 'request' which the command should
+	 * use to read the command specific part of the request.  Every command
+	 * MUST read until a flush packet is seen before sending a response.
+	 *
+	 * This field should be NULL for capabilities which are not commands.
+	 */
+	int (*command)(struct repository *r,
+		       struct argv_array *keys,
+		       struct packet_reader *request);
+};
+
+static struct protocol_capability capabilities[] = {
+	{ "agent", agent_advertise, NULL },
+	{ "ls-refs", always_advertise, ls_refs },
+	{ "fetch", upload_pack_advertise, upload_pack_v2 },
+	{ "server-option", always_advertise, NULL },
+};
+
+static void advertise_capabilities(void)
+{
+	struct strbuf capability = STRBUF_INIT;
+	struct strbuf value = STRBUF_INIT;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(capabilities); i++) {
+		struct protocol_capability *c = &capabilities[i];
+
+		if (c->advertise(the_repository, &value)) {
+			strbuf_addstr(&capability, c->name);
+
+			if (value.len) {
+				strbuf_addch(&capability, '=');
+				strbuf_addbuf(&capability, &value);
+			}
+
+			strbuf_addch(&capability, '\n');
+			packet_write(1, capability.buf, capability.len);
+		}
+
+		strbuf_reset(&capability);
+		strbuf_reset(&value);
+	}
+
+	packet_flush(1);
+	strbuf_release(&capability);
+	strbuf_release(&value);
+}
+
+static struct protocol_capability *get_capability(const char *key)
+{
+	int i;
+
+	if (!key)
+		return NULL;
+
+	for (i = 0; i < ARRAY_SIZE(capabilities); i++) {
+		struct protocol_capability *c = &capabilities[i];
+		const char *out;
+		if (skip_prefix(key, c->name, &out) && (!*out || *out == '='))
+			return c;
+	}
+
+	return NULL;
+}
+
+static int is_valid_capability(const char *key)
+{
+	const struct protocol_capability *c = get_capability(key);
+
+	return c && c->advertise(the_repository, NULL);
+}
+
+static int is_command(const char *key, struct protocol_capability **command)
+{
+	const char *out;
+
+	if (skip_prefix(key, "command=", &out)) {
+		struct protocol_capability *cmd = get_capability(out);
+
+		if (*command)
+			die("command '%s' requested after already requesting command '%s'",
+			    out, (*command)->name);
+		if (!cmd || !cmd->advertise(the_repository, NULL) || !cmd->command)
+			die("invalid command '%s'", out);
+
+		*command = cmd;
+		return 1;
+	}
+
+	return 0;
+}
+
+int has_capability(const struct argv_array *keys, const char *capability,
+		   const char **value)
+{
+	int i;
+	for (i = 0; i < keys->argc; i++) {
+		const char *out;
+		if (skip_prefix(keys->argv[i], capability, &out) &&
+		    (!*out || *out == '=')) {
+			if (value) {
+				if (*out == '=')
+					out++;
+				*value = out;
+			}
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+enum request_state {
+	PROCESS_REQUEST_KEYS,
+	PROCESS_REQUEST_DONE,
+};
+
+static int process_request(void)
+{
+	enum request_state state = PROCESS_REQUEST_KEYS;
+	struct packet_reader reader;
+	struct argv_array keys = ARGV_ARRAY_INIT;
+	struct protocol_capability *command = NULL;
+
+	packet_reader_init(&reader, 0, NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_GENTLE_ON_EOF);
+
+	/*
+	 * Check to see if the client closed their end before sending another
+	 * request.  If so we can terminate the connection.
+	 */
+	if (packet_reader_peek(&reader) == PACKET_READ_EOF)
+		return 1;
+	reader.options = PACKET_READ_CHOMP_NEWLINE;
+
+	while (state != PROCESS_REQUEST_DONE) {
+		switch (packet_reader_peek(&reader)) {
+		case PACKET_READ_EOF:
+			BUG("Should have already died when seeing EOF");
+		case PACKET_READ_NORMAL:
+			/* collect request; a sequence of keys and values */
+			if (is_command(reader.line, &command) ||
+			    is_valid_capability(reader.line))
+				argv_array_push(&keys, reader.line);
+			else
+				die("unknown capability '%s'", reader.line);
+
+			/* Consume the peeked line */
+			packet_reader_read(&reader);
+			break;
+		case PACKET_READ_FLUSH:
+			/*
+			 * If no command and no keys were given then the client
+			 * wanted to terminate the connection.
+			 */
+			if (!keys.argc)
+				return 1;
+
+			/*
+			 * The flush packet isn't consume here like it is in
+			 * the other parts of this switch statement.  This is
+			 * so that the command can read the flush packet and
+			 * see the end of the request in the same way it would
+			 * if command specific arguments were provided after a
+			 * delim packet.
+			 */
+			state = PROCESS_REQUEST_DONE;
+			break;
+		case PACKET_READ_DELIM:
+			/* Consume the peeked line */
+			packet_reader_read(&reader);
+
+			state = PROCESS_REQUEST_DONE;
+			break;
+		}
+	}
+
+	if (!command)
+		die("no command requested");
+
+	command->command(the_repository, &keys, &reader);
+
+	argv_array_clear(&keys);
+	return 0;
+}
+
+/* Main serve loop for protocol version 2 */
+void serve(struct serve_options *options)
+{
+	if (options->advertise_capabilities || !options->stateless_rpc) {
+		/* serve by default supports v2 */
+		packet_write_fmt(1, "version 2\n");
+
+		advertise_capabilities();
+		/*
+		 * If only the list of capabilities was requested exit
+		 * immediately after advertising capabilities
+		 */
+		if (options->advertise_capabilities)
+			return;
+	}
+
+	/*
+	 * If stateless-rpc was requested then exit after
+	 * a single request/response exchange
+	 */
+	if (options->stateless_rpc) {
+		process_request();
+	} else {
+		for (;;)
+			if (process_request())
+				break;
+	}
+}
diff --git a/serve.h b/serve.h
new file mode 100644
index 0000000..fe65ba9
--- /dev/null
+++ b/serve.h
@@ -0,0 +1,15 @@
+#ifndef SERVE_H
+#define SERVE_H
+
+struct argv_array;
+extern int has_capability(const struct argv_array *keys, const char *capability,
+			  const char **value);
+
+struct serve_options {
+	unsigned advertise_capabilities;
+	unsigned stateless_rpc;
+};
+#define SERVE_OPTIONS_INIT { 0 }
+extern void serve(struct serve_options *options);
+
+#endif /* SERVE_H */
diff --git a/server-info.c b/server-info.c
index 83460ec..7ce6dcd 100644
--- a/server-info.c
+++ b/server-info.c
@@ -92,8 +92,6 @@
 	int old_num;
 	int new_num;
 	int nr_alloc;
-	int nr_heads;
-	unsigned char (*head)[20];
 } **info;
 static int num_pack;
 static const char *objdir;
@@ -225,12 +223,9 @@
 	else
 		stale = 1;
 
-	for (i = 0; i < num_pack; i++) {
-		if (stale) {
+	for (i = 0; i < num_pack; i++)
+		if (stale)
 			info[i]->old_num = -1;
-			info[i]->nr_heads = 0;
-		}
-	}
 
 	/* renumber them */
 	QSORT(info, num_pack, compare_info);
diff --git a/setup.c b/setup.c
index 3e03d44..b24c811 100644
--- a/setup.c
+++ b/setup.c
@@ -539,7 +539,7 @@
 	case READ_GITFILE_ERR_NOT_A_REPO:
 		die(_("not a git repository: %s"), dir);
 	default:
-		die("BUG: unknown error code");
+		BUG("unknown error code");
 	}
 }
 
@@ -1086,7 +1086,7 @@
 		      "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set)."),
 		    dir.buf);
 	default:
-		die("BUG: unhandled setup_git_directory_1() result");
+		BUG("unhandled setup_git_directory_1() result");
 	}
 
 	if (prefix)
diff --git a/sha1-array.c b/sha1-array.c
index 838b3bf..265941f 100644
--- a/sha1-array.c
+++ b/sha1-array.c
@@ -41,9 +41,26 @@
 	array->sorted = 0;
 }
 
+
+int oid_array_for_each(struct oid_array *array,
+		       for_each_oid_fn fn,
+		       void *data)
+{
+	int i;
+
+	/* No oid_array_sort() here! See the api-oid-array.txt docs! */
+
+	for (i = 0; i < array->nr; i++) {
+		int ret = fn(array->oid + i, data);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
 int oid_array_for_each_unique(struct oid_array *array,
-				for_each_oid_fn fn,
-				void *data)
+			      for_each_oid_fn fn,
+			      void *data)
 {
 	int i;
 
diff --git a/sha1-array.h b/sha1-array.h
index 04b0756..232bf95 100644
--- a/sha1-array.h
+++ b/sha1-array.h
@@ -16,8 +16,11 @@
 
 typedef int (*for_each_oid_fn)(const struct object_id *oid,
 			       void *data);
+int oid_array_for_each(struct oid_array *array,
+		       for_each_oid_fn fn,
+		       void *data);
 int oid_array_for_each_unique(struct oid_array *array,
-			       for_each_oid_fn fn,
-			       void *data);
+			      for_each_oid_fn fn,
+			      void *data);
 
 #endif /* SHA1_ARRAY_H */
diff --git a/sha1-file.c b/sha1-file.c
index 77ccaab..555e780 100644
--- a/sha1-file.c
+++ b/sha1-file.c
@@ -23,6 +23,7 @@
 #include "sha1-lookup.h"
 #include "bulk-checkin.h"
 #include "repository.h"
+#include "replace-object.h"
 #include "streaming.h"
 #include "dir.h"
 #include "list.h"
@@ -35,12 +36,21 @@
 /* The maximum size for an object header. */
 #define MAX_HEADER_LEN 32
 
+
+#define EMPTY_TREE_SHA1_BIN_LITERAL \
+	 "\x4b\x82\x5d\xc6\x42\xcb\x6e\xb9\xa0\x60" \
+	 "\xe5\x4b\xf8\xd6\x92\x88\xfb\xee\x49\x04"
+
+#define EMPTY_BLOB_SHA1_BIN_LITERAL \
+	"\xe6\x9d\xe2\x9b\xb2\xd1\xd6\x43\x4b\x8b" \
+	"\x29\xae\x77\x5a\xd8\xc2\xe4\x8c\x53\x91"
+
 const unsigned char null_sha1[GIT_MAX_RAWSZ];
 const struct object_id null_oid;
-const struct object_id empty_tree_oid = {
+static const struct object_id empty_tree_oid = {
 	EMPTY_TREE_SHA1_BIN_LITERAL
 };
-const struct object_id empty_blob_oid = {
+static const struct object_id empty_blob_oid = {
 	EMPTY_BLOB_SHA1_BIN_LITERAL
 };
 
@@ -100,6 +110,18 @@
 	},
 };
 
+const char *empty_tree_oid_hex(void)
+{
+	static char buf[GIT_MAX_HEXSZ + 1];
+	return oid_to_hex_r(buf, the_hash_algo->empty_tree);
+}
+
+const char *empty_blob_oid_hex(void)
+{
+	static char buf[GIT_MAX_HEXSZ + 1];
+	return oid_to_hex_r(buf, the_hash_algo->empty_blob);
+}
+
 /*
  * This is meant to hold a *small* number of objects that you would
  * want read_sha1_file() to be able to return, but yet you do not want
@@ -107,7 +129,7 @@
  * application).
  */
 static struct cached_object {
-	unsigned char sha1[20];
+	struct object_id oid;
 	enum object_type type;
 	void *buf;
 	unsigned long size;
@@ -115,22 +137,22 @@
 static int cached_object_nr, cached_object_alloc;
 
 static struct cached_object empty_tree = {
-	EMPTY_TREE_SHA1_BIN_LITERAL,
+	{ EMPTY_TREE_SHA1_BIN_LITERAL },
 	OBJ_TREE,
 	"",
 	0
 };
 
-static struct cached_object *find_cached_object(const unsigned char *sha1)
+static struct cached_object *find_cached_object(const struct object_id *oid)
 {
 	int i;
 	struct cached_object *co = cached_objects;
 
 	for (i = 0; i < cached_object_nr; i++, co++) {
-		if (!hashcmp(co->sha1, sha1))
+		if (!oidcmp(&co->oid, oid))
 			return co;
 	}
-	if (!hashcmp(sha1, empty_tree.sha1))
+	if (!oidcmp(oid, the_hash_algo->empty_tree))
 		return &empty_tree;
 	return NULL;
 }
@@ -141,7 +163,7 @@
 	if (flags & HASH_RENORMALIZE)
 		return CONV_EOL_RENORMALIZE;
 	else if (flags & HASH_WRITE_OBJECT)
-	  return global_conv_flags_eol;
+		return global_conv_flags_eol | CONV_WRITE_OBJECT;
 	else
 		return 0;
 }
@@ -709,42 +731,42 @@
 	return 1;
 }
 
-static int check_and_freshen_local(const unsigned char *sha1, int freshen)
+static int check_and_freshen_local(const struct object_id *oid, int freshen)
 {
 	static struct strbuf buf = STRBUF_INIT;
 
 	strbuf_reset(&buf);
-	sha1_file_name(the_repository, &buf, sha1);
+	sha1_file_name(the_repository, &buf, oid->hash);
 
 	return check_and_freshen_file(buf.buf, freshen);
 }
 
-static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
+static int check_and_freshen_nonlocal(const struct object_id *oid, int freshen)
 {
 	struct alternate_object_database *alt;
 	prepare_alt_odb(the_repository);
 	for (alt = the_repository->objects->alt_odb_list; alt; alt = alt->next) {
-		const char *path = alt_sha1_path(alt, sha1);
+		const char *path = alt_sha1_path(alt, oid->hash);
 		if (check_and_freshen_file(path, freshen))
 			return 1;
 	}
 	return 0;
 }
 
-static int check_and_freshen(const unsigned char *sha1, int freshen)
+static int check_and_freshen(const struct object_id *oid, int freshen)
 {
-	return check_and_freshen_local(sha1, freshen) ||
-	       check_and_freshen_nonlocal(sha1, freshen);
+	return check_and_freshen_local(oid, freshen) ||
+	       check_and_freshen_nonlocal(oid, freshen);
 }
 
-int has_loose_object_nonlocal(const unsigned char *sha1)
+int has_loose_object_nonlocal(const struct object_id *oid)
 {
-	return check_and_freshen_nonlocal(sha1, 0);
+	return check_and_freshen_nonlocal(oid, 0);
 }
 
-static int has_loose_object(const unsigned char *sha1)
+static int has_loose_object(const struct object_id *oid)
 {
-	return check_and_freshen(sha1, 0);
+	return check_and_freshen(oid, 0);
 }
 
 static void mmap_limit_check(size_t length)
@@ -1230,7 +1252,8 @@
 
 int fetch_if_missing = 1;
 
-int oid_object_info_extended(const struct object_id *oid, struct object_info *oi, unsigned flags)
+int oid_object_info_extended(struct repository *r, const struct object_id *oid,
+			     struct object_info *oi, unsigned flags)
 {
 	static struct object_info blank_oi = OBJECT_INFO_INIT;
 	struct pack_entry e;
@@ -1239,7 +1262,7 @@
 	int already_retried = 0;
 
 	if (flags & OBJECT_INFO_LOOKUP_REPLACE)
-		real = lookup_replace_object(oid);
+		real = lookup_replace_object(r, oid);
 
 	if (is_null_oid(real))
 		return -1;
@@ -1248,7 +1271,7 @@
 		oi = &blank_oi;
 
 	if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
-		struct cached_object *co = find_cached_object(real->hash);
+		struct cached_object *co = find_cached_object(real);
 		if (co) {
 			if (oi->typep)
 				*(oi->typep) = co->type;
@@ -1268,29 +1291,31 @@
 	}
 
 	while (1) {
-		if (find_pack_entry(the_repository, real->hash, &e))
+		if (find_pack_entry(r, real, &e))
 			break;
 
 		if (flags & OBJECT_INFO_IGNORE_LOOSE)
 			return -1;
 
 		/* Most likely it's a loose object. */
-		if (!sha1_loose_object_info(the_repository, real->hash, oi, flags))
+		if (!sha1_loose_object_info(r, real->hash, oi, flags))
 			return 0;
 
 		/* Not a loose object; someone else may have just packed it. */
 		if (!(flags & OBJECT_INFO_QUICK)) {
-			reprepare_packed_git(the_repository);
-			if (find_pack_entry(the_repository, real->hash, &e))
+			reprepare_packed_git(r);
+			if (find_pack_entry(r, real, &e))
 				break;
 		}
 
 		/* Check if it is a missing object */
 		if (fetch_if_missing && repository_format_partial_clone &&
-		    !already_retried) {
+		    !already_retried && r == the_repository) {
 			/*
-			 * TODO Investigate haveing fetch_object() return
+			 * TODO Investigate having fetch_object() return
 			 * TODO error/success and stopping the music here.
+			 * TODO Pass a repository struct through fetch_object,
+			 * such that arbitrary repositories work.
 			 */
 			fetch_object(repository_format_partial_clone, real->hash);
 			already_retried = 1;
@@ -1306,10 +1331,10 @@
 		 * information below, so return early.
 		 */
 		return 0;
-	rtype = packed_object_info(e.p, e.offset, oi);
+	rtype = packed_object_info(r, e.p, e.offset, oi);
 	if (rtype < 0) {
 		mark_bad_packed_object(e.p, real->hash);
-		return oid_object_info_extended(real, oi, 0);
+		return oid_object_info_extended(r, real, oi, 0);
 	} else if (oi->whence == OI_PACKED) {
 		oi->u.packed.offset = e.offset;
 		oi->u.packed.pack = e.p;
@@ -1321,15 +1346,17 @@
 }
 
 /* returns enum object_type or negative */
-int oid_object_info(const struct object_id *oid, unsigned long *sizep)
+int oid_object_info(struct repository *r,
+		    const struct object_id *oid,
+		    unsigned long *sizep)
 {
 	enum object_type type;
 	struct object_info oi = OBJECT_INFO_INIT;
 
 	oi.typep = &type;
 	oi.sizep = sizep;
-	if (oid_object_info_extended(oid, &oi,
-				     OBJECT_INFO_LOOKUP_REPLACE) < 0)
+	if (oid_object_info_extended(r, oid, &oi,
+				      OBJECT_INFO_LOOKUP_REPLACE) < 0)
 		return -1;
 	return type;
 }
@@ -1346,7 +1373,7 @@
 
 	hashcpy(oid.hash, sha1);
 
-	if (oid_object_info_extended(&oid, &oi, 0) < 0)
+	if (oid_object_info_extended(the_repository, &oid, &oi, 0) < 0)
 		return NULL;
 	return content;
 }
@@ -1357,7 +1384,7 @@
 	struct cached_object *co;
 
 	hash_object_file(buf, len, type_name(type), oid);
-	if (has_sha1_file(oid->hash) || find_cached_object(oid->hash))
+	if (has_sha1_file(oid->hash) || find_cached_object(oid))
 		return 0;
 	ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
 	co = &cached_objects[cached_object_nr++];
@@ -1365,7 +1392,7 @@
 	co->type = type;
 	co->buf = xmalloc(len);
 	memcpy(co->buf, buf, len);
-	hashcpy(co->sha1, oid->hash);
+	oidcpy(&co->oid, oid);
 	return 0;
 }
 
@@ -1383,8 +1410,8 @@
 	const struct packed_git *p;
 	const char *path;
 	struct stat st;
-	const struct object_id *repl = lookup_replace ? lookup_replace_object(oid)
-						      : oid;
+	const struct object_id *repl = lookup_replace ?
+		lookup_replace_object(the_repository, oid) : oid;
 
 	errno = 0;
 	data = read_object(repl->hash, type, size);
@@ -1661,15 +1688,15 @@
 	return finalize_object_file(tmp_file.buf, filename.buf);
 }
 
-static int freshen_loose_object(const unsigned char *sha1)
+static int freshen_loose_object(const struct object_id *oid)
 {
-	return check_and_freshen(sha1, 1);
+	return check_and_freshen(oid, 1);
 }
 
-static int freshen_packed_object(const unsigned char *sha1)
+static int freshen_packed_object(const struct object_id *oid)
 {
 	struct pack_entry e;
-	if (!find_pack_entry(the_repository, sha1, &e))
+	if (!find_pack_entry(the_repository, oid, &e))
 		return 0;
 	if (e.p->freshened)
 		return 1;
@@ -1689,7 +1716,7 @@
 	 * it out into .git/objects/??/?{38} file.
 	 */
 	write_object_file_prepare(buf, len, type, oid, hdr, &hdrlen);
-	if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
+	if (freshen_packed_object(oid) || freshen_loose_object(oid))
 		return 0;
 	return write_loose_object(oid, hdr, hdrlen, buf, len, 0);
 }
@@ -1708,7 +1735,7 @@
 
 	if (!(flags & HASH_WRITE_OBJECT))
 		goto cleanup;
-	if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
+	if (freshen_packed_object(oid) || freshen_loose_object(oid))
 		goto cleanup;
 	status = write_loose_object(oid, header, hdrlen, buf, len, 0);
 
@@ -1726,7 +1753,7 @@
 	int hdrlen;
 	int ret;
 
-	if (has_loose_object(oid->hash))
+	if (has_loose_object(oid))
 		return 0;
 	buf = read_object(oid->hash, &type, &len);
 	if (!buf)
@@ -1744,7 +1771,7 @@
 	if (!startup_info->have_repository)
 		return 0;
 	hashcpy(oid.hash, sha1);
-	return oid_object_info_extended(&oid, NULL,
+	return oid_object_info_extended(the_repository, &oid, NULL,
 					flags | OBJECT_INFO_SKIP_CACHED) >= 0;
 }
 
@@ -1987,7 +2014,7 @@
 
 void assert_oid_type(const struct object_id *oid, enum object_type expect)
 {
-	enum object_type type = oid_object_info(oid, NULL);
+	enum object_type type = oid_object_info(the_repository, oid, NULL);
 	if (type < 0)
 		die("%s is not a valid object", oid_to_hex(oid));
 	if (type != expect)
@@ -2226,7 +2253,7 @@
 		goto out;
 	}
 
-	if (*type == OBJ_BLOB) {
+	if (*type == OBJ_BLOB && *size > big_file_threshold) {
 		if (check_stream_sha1(&stream, hdr, *size, path, expected_oid->hash) < 0)
 			goto out;
 	} else {
diff --git a/sha1-lookup.c b/sha1-lookup.c
index 8d0b1db..796ab68 100644
--- a/sha1-lookup.c
+++ b/sha1-lookup.c
@@ -81,7 +81,7 @@
 				mi = (nr - 1) * (miv - lov) / (hiv - lov);
 				if (lo <= mi && mi < hi)
 					break;
-				die("BUG: assertion failed in binary search");
+				BUG("assertion failed in binary search");
 			}
 		}
 	}
diff --git a/sha1-name.c b/sha1-name.c
index 5b93bf8..60d9ef3 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -223,7 +223,7 @@
 
 static int disambiguate_commit_only(const struct object_id *oid, void *cb_data_unused)
 {
-	int kind = oid_object_info(oid, NULL);
+	int kind = oid_object_info(the_repository, oid, NULL);
 	return kind == OBJ_COMMIT;
 }
 
@@ -232,7 +232,7 @@
 	struct object *obj;
 	int kind;
 
-	kind = oid_object_info(oid, NULL);
+	kind = oid_object_info(the_repository, oid, NULL);
 	if (kind == OBJ_COMMIT)
 		return 1;
 	if (kind != OBJ_TAG)
@@ -247,7 +247,7 @@
 
 static int disambiguate_tree_only(const struct object_id *oid, void *cb_data_unused)
 {
-	int kind = oid_object_info(oid, NULL);
+	int kind = oid_object_info(the_repository, oid, NULL);
 	return kind == OBJ_TREE;
 }
 
@@ -256,7 +256,7 @@
 	struct object *obj;
 	int kind;
 
-	kind = oid_object_info(oid, NULL);
+	kind = oid_object_info(the_repository, oid, NULL);
 	if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 		return 1;
 	if (kind != OBJ_TAG)
@@ -271,7 +271,7 @@
 
 static int disambiguate_blob_only(const struct object_id *oid, void *cb_data_unused)
 {
-	int kind = oid_object_info(oid, NULL);
+	int kind = oid_object_info(the_repository, oid, NULL);
 	return kind == OBJ_BLOB;
 }
 
@@ -346,11 +346,10 @@
 	struct strbuf desc = STRBUF_INIT;
 	int type;
 
-
 	if (ds->fn && !ds->fn(oid, ds->cb_data))
 		return 0;
 
-	type = oid_object_info(oid, NULL);
+	type = oid_object_info(the_repository, oid, NULL);
 	if (type == OBJ_COMMIT) {
 		struct commit *commit = lookup_commit(oid);
 		if (commit) {
@@ -373,6 +372,40 @@
 	return 0;
 }
 
+static int collect_ambiguous(const struct object_id *oid, void *data)
+{
+	oid_array_append(data, oid);
+	return 0;
+}
+
+static int sort_ambiguous(const void *a, const void *b)
+{
+	int a_type = oid_object_info(the_repository, a, NULL);
+	int b_type = oid_object_info(the_repository, b, NULL);
+	int a_type_sort;
+	int b_type_sort;
+
+	/*
+	 * Sorts by hash within the same object type, just as
+	 * oid_array_for_each_unique() would do.
+	 */
+	if (a_type == b_type)
+		return oidcmp(a, b);
+
+	/*
+	 * Between object types show tags, then commits, and finally
+	 * trees and blobs.
+	 *
+	 * The object_type enum is commit, tree, blob, tag, but we
+	 * want tag, commit, tree blob. Cleverly (perhaps too
+	 * cleverly) do that with modulus, since the enum assigns 1 to
+	 * commit, so tag becomes 0.
+	 */
+	a_type_sort = a_type % 4;
+	b_type_sort = b_type % 4;
+	return a_type_sort > b_type_sort ? 1 : -1;
+}
+
 static int get_short_oid(const char *name, int len, struct object_id *oid,
 			  unsigned flags)
 {
@@ -384,7 +417,7 @@
 		return -1;
 
 	if (HAS_MULTI_BITS(flags & GET_OID_DISAMBIGUATORS))
-		die("BUG: multiple get_short_oid disambiguator flags");
+		BUG("multiple get_short_oid disambiguator flags");
 
 	if (flags & GET_OID_COMMIT)
 		ds.fn = disambiguate_commit_only;
@@ -404,6 +437,8 @@
 	status = finish_object_disambiguation(&ds, oid);
 
 	if (!quietly && (status == SHORT_NAME_AMBIGUOUS)) {
+		struct oid_array collect = OID_ARRAY_INIT;
+
 		error(_("short SHA1 %s is ambiguous"), ds.hex_pfx);
 
 		/*
@@ -416,18 +451,17 @@
 			ds.fn = NULL;
 
 		advise(_("The candidates are:"));
-		for_each_abbrev(ds.hex_pfx, show_ambiguous_object, &ds);
+		for_each_abbrev(ds.hex_pfx, collect_ambiguous, &collect);
+		QSORT(collect.oid, collect.nr, sort_ambiguous);
+
+		if (oid_array_for_each(&collect, show_ambiguous_object, &ds))
+			BUG("show_ambiguous_object shouldn't return non-zero");
+		oid_array_clear(&collect);
 	}
 
 	return status;
 }
 
-static int collect_ambiguous(const struct object_id *oid, void *data)
-{
-	oid_array_append(data, oid);
-	return 0;
-}
-
 int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 {
 	struct oid_array collect = OID_ARRAY_INIT;
@@ -864,7 +898,7 @@
 		if (o->type == OBJ_TAG)
 			o = ((struct tag*) o)->tagged;
 		else if (o->type == OBJ_COMMIT)
-			o = &(((struct commit *) o)->tree->object);
+			o = &(get_commit_tree(((struct commit *)o))->object);
 		else {
 			if (name)
 				error("%.*s: expected %s type, but the object "
@@ -1685,8 +1719,8 @@
 			if (new_filename)
 				filename = new_filename;
 			if (flags & GET_OID_FOLLOW_SYMLINKS) {
-				ret = get_tree_entry_follow_symlinks(tree_oid.hash,
-					filename, oid->hash, &oc->symlink_path,
+				ret = get_tree_entry_follow_symlinks(&tree_oid,
+					filename, oid, &oc->symlink_path,
 					&oc->mode);
 			} else {
 				ret = get_tree_entry(&tree_oid, filename, oid,
@@ -1698,7 +1732,6 @@
 								   name, len);
 				}
 			}
-			hashcpy(oc->tree, tree_oid.hash);
 			if (flags & GET_OID_RECORD_PATH)
 				oc->path = xstrdup(filename);
 
@@ -1729,6 +1762,6 @@
 int get_oid_with_context(const char *str, unsigned flags, struct object_id *oid, struct object_context *oc)
 {
 	if (flags & GET_OID_FOLLOW_SYMLINKS && flags & GET_OID_ONLY_TO_DIE)
-		die("BUG: incompatible flags for get_sha1_with_context");
+		BUG("incompatible flags for get_sha1_with_context");
 	return get_oid_with_context_1(str, flags, NULL, oid, oc);
 }
diff --git a/shallow.c b/shallow.c
index df4d44e..9ff83ca 100644
--- a/shallow.c
+++ b/shallow.c
@@ -20,7 +20,7 @@
 void set_alternate_shallow_file(const char *path, int override)
 {
 	if (is_shallow != -1)
-		die("BUG: is_repository_shallow must not be called before set_alternate_shallow_file");
+		BUG("is_repository_shallow must not be called before set_alternate_shallow_file");
 	if (alternate_shallow_file && !override)
 		return;
 	free(alternate_shallow_file);
@@ -218,7 +218,7 @@
 static void check_shallow_file_for_update(void)
 {
 	if (is_shallow == -1)
-		die("BUG: shallow must be initialized by now");
+		BUG("shallow must be initialized by now");
 
 	if (!stat_validity_check(&shallow_stat, git_path_shallow()))
 		die("shallow file has changed since we read it");
@@ -353,7 +353,7 @@
  */
 void prune_shallow(int show_only)
 {
-	static struct lock_file shallow_lock;
+	struct lock_file shallow_lock = LOCK_INIT;
 	struct strbuf sb = STRBUF_INIT;
 	int fd;
 
@@ -446,7 +446,7 @@
 	void *p;
 	if (!info->pool_count || size > info->end - info->free) {
 		if (size > POOL_SIZE)
-			die("BUG: pool size too small for %d in paint_alloc()",
+			BUG("pool size too small for %d in paint_alloc()",
 			    size);
 		info->pool_count++;
 		REALLOC_ARRAY(info->pools, info->pool_count);
diff --git a/shell.c b/shell.c
index 0200d10..40084a3 100644
--- a/shell.c
+++ b/shell.c
@@ -3,6 +3,7 @@
 #include "exec-cmd.h"
 #include "strbuf.h"
 #include "run-command.h"
+#include "alias.h"
 
 #define COMMAND_DIR "git-shell-commands"
 #define HELP_COMMAND COMMAND_DIR "/help"
diff --git a/sideband.c b/sideband.c
index 6d7f943..325bf0e 100644
--- a/sideband.c
+++ b/sideband.c
@@ -13,7 +13,7 @@
  * the remote died unexpectedly.  A flush() concludes the stream.
  */
 
-#define PREFIX "remote: "
+#define DISPLAY_PREFIX "remote: "
 
 #define ANSI_SUFFIX "\033[K"
 #define DUMB_SUFFIX "        "
@@ -49,7 +49,7 @@
 		switch (band) {
 		case 3:
 			strbuf_addf(&outbuf, "%s%s%s", outbuf.len ? "\n" : "",
-				    PREFIX, buf + 1);
+				    DISPLAY_PREFIX, buf + 1);
 			retval = SIDEBAND_REMOTE_ERROR;
 			break;
 		case 2:
@@ -67,7 +67,7 @@
 				int linelen = brk - b;
 
 				if (!outbuf.len)
-					strbuf_addstr(&outbuf, PREFIX);
+					strbuf_addstr(&outbuf, DISPLAY_PREFIX);
 				if (linelen > 0) {
 					strbuf_addf(&outbuf, "%.*s%s%c",
 						    linelen, b, suffix, *brk);
@@ -81,8 +81,8 @@
 			}
 
 			if (*b)
-				strbuf_addf(&outbuf, "%s%s",
-					    outbuf.len ? "" : PREFIX, b);
+				strbuf_addf(&outbuf, "%s%s", outbuf.len ?
+					    "" : DISPLAY_PREFIX, b);
 			break;
 		case 1:
 			write_or_die(out, buf + 1, len);
diff --git a/sigchain.c b/sigchain.c
index 2ac43bb..022677b 100644
--- a/sigchain.c
+++ b/sigchain.c
@@ -13,7 +13,7 @@
 static void check_signum(int sig)
 {
 	if (sig < 1 || sig >= SIGCHAIN_MAX_SIGNALS)
-		die("BUG: signal out of range: %d", sig);
+		BUG("signal out of range: %d", sig);
 }
 
 int sigchain_push(int sig, sigchain_fun f)
diff --git a/split-index.c b/split-index.c
index 3eb8ff1..660c75f 100644
--- a/split-index.c
+++ b/split-index.c
@@ -18,12 +18,12 @@
 	struct split_index *si;
 	int ret;
 
-	if (sz < 20)
+	if (sz < the_hash_algo->rawsz)
 		return error("corrupt link extension (too short)");
 	si = init_split_index(istate);
-	hashcpy(si->base_sha1, data);
-	data += 20;
-	sz -= 20;
+	hashcpy(si->base_oid.hash, data);
+	data += the_hash_algo->rawsz;
+	sz -= the_hash_algo->rawsz;
 	if (!sz)
 		return 0;
 	si->delete_bitmap = ewah_new();
@@ -45,7 +45,7 @@
 			 struct index_state *istate)
 {
 	struct split_index *si = istate->split_index;
-	strbuf_add(sb, si->base_sha1, 20);
+	strbuf_add(sb, si->base_oid.hash, the_hash_algo->rawsz);
 	if (!si->delete_bitmap && !si->replace_bitmap)
 		return 0;
 	ewah_serialize_strbuf(si->delete_bitmap, sb);
diff --git a/split-index.h b/split-index.h
index 43d6682..7a435ca 100644
--- a/split-index.h
+++ b/split-index.h
@@ -1,12 +1,14 @@
 #ifndef SPLIT_INDEX_H
 #define SPLIT_INDEX_H
 
+#include "cache.h"
+
 struct index_state;
 struct strbuf;
 struct ewah_bitmap;
 
 struct split_index {
-	unsigned char base_sha1[20];
+	struct object_id base_oid;
 	struct index_state *base;
 	struct ewah_bitmap *delete_bitmap;
 	struct ewah_bitmap *replace_bitmap;
diff --git a/strbuf.c b/strbuf.c
index 43a840c..b0716ac 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "refs.h"
+#include "string-list.h"
 #include "utf8.h"
 
 int starts_with(const char *str, const char *prefix)
@@ -11,6 +12,15 @@
 			return 0;
 }
 
+int istarts_with(const char *str, const char *prefix)
+{
+	for (; ; str++, prefix++)
+		if (!*prefix)
+			return 1;
+		else if (tolower(*str) != tolower(*prefix))
+			return 0;
+}
+
 int skip_to_optional_arg_default(const char *str, const char *prefix,
 				 const char **arg, const char *def)
 {
@@ -171,6 +181,21 @@
 	return ret;
 }
 
+void strbuf_add_separated_string_list(struct strbuf *str,
+				      const char *sep,
+				      struct string_list *slist)
+{
+	struct string_list_item *item;
+	int sep_needed = 0;
+
+	for_each_string_list_item(item, slist) {
+		if (sep_needed)
+			strbuf_addstr(str, sep);
+		strbuf_addstr(str, item->string);
+		sep_needed = 1;
+	}
+}
+
 void strbuf_list_free(struct strbuf **sbs)
 {
 	struct strbuf **s = sbs;
@@ -309,12 +334,12 @@
 	len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, cp);
 	va_end(cp);
 	if (len < 0)
-		die("BUG: your vsnprintf is broken (returned %d)", len);
+		BUG("your vsnprintf is broken (returned %d)", len);
 	if (len > strbuf_avail(sb)) {
 		strbuf_grow(sb, len);
 		len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 		if (len > strbuf_avail(sb))
-			die("BUG: your vsnprintf is broken (insatiable)");
+			BUG("your vsnprintf is broken (insatiable)");
 	}
 	strbuf_setlen(sb, sb->len + len);
 }
@@ -793,7 +818,18 @@
 	result = xmallocz(len);
 	for (i = 0; i < len; i++)
 		result[i] = tolower(string[i]);
-	result[i] = '\0';
+	return result;
+}
+
+char *xstrdup_toupper(const char *string)
+{
+	char *result;
+	size_t len, i;
+
+	len = strlen(string);
+	result = xmallocz(len);
+	for (i = 0; i < len; i++)
+		result[i] = toupper(string[i]);
 	return result;
 }
 
diff --git a/strbuf.h b/strbuf.h
index 4efa80c..60a35ae 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -1,6 +1,8 @@
 #ifndef STRBUF_H
 #define STRBUF_H
 
+struct string_list;
+
 /**
  * strbuf's are meant to be used with all the usual C string and memory
  * APIs. Given that the length of the buffer is known, it's often better to
@@ -537,6 +539,20 @@
 	return strbuf_split_max(sb, terminator, 0);
 }
 
+/*
+ * Adds all strings of a string list to the strbuf, separated by the given
+ * separator.  For example, if sep is
+ *   ', '
+ * and slist contains
+ *   ['element1', 'element2', ..., 'elementN'],
+ * then write:
+ *   'element1, element2, ..., elementN'
+ * to str.  If only one element, just write "element1" to str.
+ */
+extern void strbuf_add_separated_string_list(struct strbuf *str,
+					     const char *sep,
+					     struct string_list *slist);
+
 /**
  * Free a NULL-terminated list of strbufs (for example, the return
  * values of the strbuf_split*() functions).
@@ -616,6 +632,7 @@
 extern int fprintf_ln(FILE *fp, const char *fmt, ...);
 
 char *xstrdup_tolower(const char *);
+char *xstrdup_toupper(const char *);
 
 /**
  * Create a newly allocated string using printf format. You can do this easily
diff --git a/streaming.c b/streaming.c
index 7d55ba6..d1e6b2d 100644
--- a/streaming.c
+++ b/streaming.c
@@ -5,6 +5,7 @@
 #include "streaming.h"
 #include "repository.h"
 #include "object-store.h"
+#include "replace-object.h"
 #include "packfile.h"
 
 enum input_source {
@@ -116,7 +117,7 @@
 
 	oi->typep = type;
 	oi->sizep = &size;
-	status = oid_object_info_extended(oid, oi, 0);
+	status = oid_object_info_extended(the_repository, oid, oi, 0);
 	if (status < 0)
 		return stream_error;
 
@@ -139,7 +140,7 @@
 {
 	struct git_istream *st;
 	struct object_info oi = OBJECT_INFO_INIT;
-	const struct object_id *real = lookup_replace_object(oid);
+	const struct object_id *real = lookup_replace_object(the_repository, oid);
 	enum input_source src = istream_source(real, type, &oi);
 
 	if (src < 0)
diff --git a/submodule-config.c b/submodule-config.c
index 3f20757..388ef1f 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -44,7 +44,7 @@
 	const struct submodule_entry *b = entry_or_key;
 
 	return strcmp(a->config->path, b->config->path) ||
-	       hashcmp(a->config->gitmodules_sha1, b->config->gitmodules_sha1);
+	       oidcmp(&a->config->gitmodules_oid, &b->config->gitmodules_oid);
 }
 
 static int config_name_cmp(const void *unused_cmp_data,
@@ -56,7 +56,7 @@
 	const struct submodule_entry *b = entry_or_key;
 
 	return strcmp(a->config->name, b->config->name) ||
-	       hashcmp(a->config->gitmodules_sha1, b->config->gitmodules_sha1);
+	       oidcmp(&a->config->gitmodules_oid, &b->config->gitmodules_oid);
 }
 
 static struct submodule_cache *submodule_cache_alloc(void)
@@ -109,17 +109,17 @@
 	free(cache);
 }
 
-static unsigned int hash_sha1_string(const unsigned char *sha1,
-				     const char *string)
+static unsigned int hash_oid_string(const struct object_id *oid,
+				    const char *string)
 {
-	return memhash(sha1, 20) + strhash(string);
+	return memhash(oid->hash, the_hash_algo->rawsz) + strhash(string);
 }
 
 static void cache_put_path(struct submodule_cache *cache,
 			   struct submodule *submodule)
 {
-	unsigned int hash = hash_sha1_string(submodule->gitmodules_sha1,
-					     submodule->path);
+	unsigned int hash = hash_oid_string(&submodule->gitmodules_oid,
+					    submodule->path);
 	struct submodule_entry *e = xmalloc(sizeof(*e));
 	hashmap_entry_init(e, hash);
 	e->config = submodule;
@@ -129,8 +129,8 @@
 static void cache_remove_path(struct submodule_cache *cache,
 			      struct submodule *submodule)
 {
-	unsigned int hash = hash_sha1_string(submodule->gitmodules_sha1,
-					     submodule->path);
+	unsigned int hash = hash_oid_string(&submodule->gitmodules_oid,
+					    submodule->path);
 	struct submodule_entry e;
 	struct submodule_entry *removed;
 	hashmap_entry_init(&e, hash);
@@ -142,8 +142,8 @@
 static void cache_add(struct submodule_cache *cache,
 		      struct submodule *submodule)
 {
-	unsigned int hash = hash_sha1_string(submodule->gitmodules_sha1,
-					     submodule->name);
+	unsigned int hash = hash_oid_string(&submodule->gitmodules_oid,
+					    submodule->name);
 	struct submodule_entry *e = xmalloc(sizeof(*e));
 	hashmap_entry_init(e, hash);
 	e->config = submodule;
@@ -151,14 +151,14 @@
 }
 
 static const struct submodule *cache_lookup_path(struct submodule_cache *cache,
-		const unsigned char *gitmodules_sha1, const char *path)
+		const struct object_id *gitmodules_oid, const char *path)
 {
 	struct submodule_entry *entry;
-	unsigned int hash = hash_sha1_string(gitmodules_sha1, path);
+	unsigned int hash = hash_oid_string(gitmodules_oid, path);
 	struct submodule_entry key;
 	struct submodule key_config;
 
-	hashcpy(key_config.gitmodules_sha1, gitmodules_sha1);
+	oidcpy(&key_config.gitmodules_oid, gitmodules_oid);
 	key_config.path = path;
 
 	hashmap_entry_init(&key, hash);
@@ -171,14 +171,14 @@
 }
 
 static struct submodule *cache_lookup_name(struct submodule_cache *cache,
-		const unsigned char *gitmodules_sha1, const char *name)
+		const struct object_id *gitmodules_oid, const char *name)
 {
 	struct submodule_entry *entry;
-	unsigned int hash = hash_sha1_string(gitmodules_sha1, name);
+	unsigned int hash = hash_oid_string(gitmodules_oid, name);
 	struct submodule_entry key;
 	struct submodule key_config;
 
-	hashcpy(key_config.gitmodules_sha1, gitmodules_sha1);
+	oidcpy(&key_config.gitmodules_oid, gitmodules_oid);
 	key_config.name = name;
 
 	hashmap_entry_init(&key, hash);
@@ -190,6 +190,31 @@
 	return NULL;
 }
 
+int check_submodule_name(const char *name)
+{
+	/* Disallow empty names */
+	if (!*name)
+		return -1;
+
+	/*
+	 * Look for '..' as a path component. Check both '/' and '\\' as
+	 * separators rather than is_dir_sep(), because we want the name rules
+	 * to be consistent across platforms.
+	 */
+	goto in_component; /* always start inside component */
+	while (*name) {
+		char c = *name++;
+		if (c == '/' || c == '\\') {
+in_component:
+			if (name[0] == '.' && name[1] == '.' &&
+			    (!name[2] || name[2] == '/' || name[2] == '\\'))
+				return -1;
+		}
+	}
+
+	return 0;
+}
+
 static int name_and_item_from_var(const char *var, struct strbuf *name,
 				  struct strbuf *item)
 {
@@ -201,18 +226,24 @@
 		return 0;
 
 	strbuf_add(name, subsection, subsection_len);
+	if (check_submodule_name(name->buf) < 0) {
+		warning(_("ignoring suspicious submodule name: %s"), name->buf);
+		strbuf_release(name);
+		return 0;
+	}
+
 	strbuf_addstr(item, key);
 
 	return 1;
 }
 
 static struct submodule *lookup_or_create_by_name(struct submodule_cache *cache,
-		const unsigned char *gitmodules_sha1, const char *name)
+		const struct object_id *gitmodules_oid, const char *name)
 {
 	struct submodule *submodule;
 	struct strbuf name_buf = STRBUF_INIT;
 
-	submodule = cache_lookup_name(cache, gitmodules_sha1, name);
+	submodule = cache_lookup_name(cache, gitmodules_oid, name);
 	if (submodule)
 		return submodule;
 
@@ -230,7 +261,7 @@
 	submodule->branch = NULL;
 	submodule->recommend_shallow = -1;
 
-	hashcpy(submodule->gitmodules_sha1, gitmodules_sha1);
+	oidcpy(&submodule->gitmodules_oid, gitmodules_oid);
 
 	cache_add(cache, submodule);
 
@@ -341,12 +372,12 @@
 	return parse_push_recurse(opt, arg, 1);
 }
 
-static void warn_multiple_config(const unsigned char *treeish_name,
+static void warn_multiple_config(const struct object_id *treeish_name,
 				 const char *name, const char *option)
 {
 	const char *commit_string = "WORKTREE";
 	if (treeish_name)
-		commit_string = sha1_to_hex(treeish_name);
+		commit_string = oid_to_hex(treeish_name);
 	warning("%s:.gitmodules, multiple configurations found for "
 			"'submodule.%s.%s'. Skipping second one!",
 			commit_string, name, option);
@@ -354,8 +385,8 @@
 
 struct parse_config_parameter {
 	struct submodule_cache *cache;
-	const unsigned char *treeish_name;
-	const unsigned char *gitmodules_sha1;
+	const struct object_id *treeish_name;
+	const struct object_id *gitmodules_oid;
 	int overwrite;
 };
 
@@ -371,7 +402,7 @@
 		return 0;
 
 	submodule = lookup_or_create_by_name(me->cache,
-					     me->gitmodules_sha1,
+					     me->gitmodules_oid,
 					     name.buf);
 
 	if (!strcmp(item.buf, "path")) {
@@ -389,7 +420,7 @@
 		}
 	} else if (!strcmp(item.buf, "fetchrecursesubmodules")) {
 		/* when parsing worktree configurations we can die early */
-		int die_on_error = is_null_sha1(me->gitmodules_sha1);
+		int die_on_error = is_null_oid(me->gitmodules_oid);
 		if (!me->overwrite &&
 		    submodule->fetch_recurse != RECURSE_SUBMODULES_NONE)
 			warn_multiple_config(me->treeish_name, submodule->name,
@@ -511,10 +542,10 @@
 
 	switch (lookup_type) {
 	case lookup_name:
-		submodule = cache_lookup_name(cache, oid.hash, key);
+		submodule = cache_lookup_name(cache, &oid, key);
 		break;
 	case lookup_path:
-		submodule = cache_lookup_path(cache, oid.hash, key);
+		submodule = cache_lookup_path(cache, &oid, key);
 		break;
 	}
 	if (submodule)
@@ -526,8 +557,8 @@
 
 	/* fill the submodule config into the cache */
 	parameter.cache = cache;
-	parameter.treeish_name = treeish_name->hash;
-	parameter.gitmodules_sha1 = oid.hash;
+	parameter.treeish_name = treeish_name;
+	parameter.gitmodules_oid = &oid;
 	parameter.overwrite = 0;
 	git_config_from_mem(parse_config, CONFIG_ORIGIN_SUBMODULE_BLOB, rev.buf,
 			config, config_size, &parameter);
@@ -536,9 +567,9 @@
 
 	switch (lookup_type) {
 	case lookup_name:
-		return cache_lookup_name(cache, oid.hash, key);
+		return cache_lookup_name(cache, &oid, key);
 	case lookup_path:
-		return cache_lookup_path(cache, oid.hash, key);
+		return cache_lookup_path(cache, &oid, key);
 	default:
 		return NULL;
 	}
@@ -567,7 +598,7 @@
 
 	parameter.cache = repo->submodule_cache;
 	parameter.treeish_name = NULL;
-	parameter.gitmodules_sha1 = null_sha1;
+	parameter.gitmodules_oid = &null_oid;
 	parameter.overwrite = 1;
 
 	return parse_config(var, value, &parameter);
@@ -619,31 +650,24 @@
 		repo_read_gitmodules(repo);
 }
 
-const struct submodule *submodule_from_name(const struct object_id *treeish_name,
+const struct submodule *submodule_from_name(struct repository *r,
+					    const struct object_id *treeish_name,
 		const char *name)
 {
-	gitmodules_read_check(the_repository);
-	return config_from(the_repository->submodule_cache, treeish_name, name, lookup_name);
+	gitmodules_read_check(r);
+	return config_from(r->submodule_cache, treeish_name, name, lookup_name);
 }
 
-const struct submodule *submodule_from_path(const struct object_id *treeish_name,
+const struct submodule *submodule_from_path(struct repository *r,
+					    const struct object_id *treeish_name,
 		const char *path)
 {
-	gitmodules_read_check(the_repository);
-	return config_from(the_repository->submodule_cache, treeish_name, path, lookup_path);
+	gitmodules_read_check(r);
+	return config_from(r->submodule_cache, treeish_name, path, lookup_path);
 }
 
-const struct submodule *submodule_from_cache(struct repository *repo,
-					     const struct object_id *treeish_name,
-					     const char *key)
+void submodule_free(struct repository *r)
 {
-	gitmodules_read_check(repo);
-	return config_from(repo->submodule_cache, treeish_name,
-			   key, lookup_path);
-}
-
-void submodule_free(void)
-{
-	if (the_repository->submodule_cache)
-		submodule_cache_clear(the_repository->submodule_cache);
+	if (r->submodule_cache)
+		submodule_cache_clear(r->submodule_cache);
 }
diff --git a/submodule-config.h b/submodule-config.h
index a5503a5..ca1f94e 100644
--- a/submodule-config.h
+++ b/submodule-config.h
@@ -1,6 +1,7 @@
 #ifndef SUBMODULE_CONFIG_CACHE_H
 #define SUBMODULE_CONFIG_CACHE_H
 
+#include "cache.h"
 #include "hashmap.h"
 #include "submodule.h"
 #include "strbuf.h"
@@ -17,13 +18,13 @@
 	const char *ignore;
 	const char *branch;
 	struct submodule_update_strategy update_strategy;
-	/* the sha1 blob id of the responsible .gitmodules file */
-	unsigned char gitmodules_sha1[20];
+	/* the object id of the responsible .gitmodules file */
+	struct object_id gitmodules_oid;
 	int recommend_shallow;
 };
 
 #define SUBMODULE_INIT { NULL, NULL, NULL, RECURSE_SUBMODULES_NONE, \
-	NULL, NULL, SUBMODULE_UPDATE_STRATEGY_INIT, {0}, -1 };
+	NULL, NULL, SUBMODULE_UPDATE_STRATEGY_INIT, { { 0 } }, -1 };
 
 struct submodule_cache;
 struct repository;
@@ -39,13 +40,19 @@
 extern int parse_push_recurse_submodules_arg(const char *opt, const char *arg);
 extern void repo_read_gitmodules(struct repository *repo);
 extern void gitmodules_config_oid(const struct object_id *commit_oid);
-extern const struct submodule *submodule_from_name(
-		const struct object_id *commit_or_tree, const char *name);
-extern const struct submodule *submodule_from_path(
-		const struct object_id *commit_or_tree, const char *path);
-extern const struct submodule *submodule_from_cache(struct repository *repo,
-						    const struct object_id *treeish_name,
-						    const char *key);
-extern void submodule_free(void);
+const struct submodule *submodule_from_name(struct repository *r,
+					    const struct object_id *commit_or_tree,
+					    const char *name);
+const struct submodule *submodule_from_path(struct repository *r,
+					    const struct object_id *commit_or_tree,
+					    const char *path);
+void submodule_free(struct repository *r);
+
+/*
+ * Returns 0 if the name is syntactically acceptable as a submodule "name"
+ * (e.g., that may be found in the subsection of a .gitmodules file) and -1
+ * otherwise.
+ */
+int check_submodule_name(const char *name);
 
 #endif /* SUBMODULE_CONFIG_H */
diff --git a/submodule.c b/submodule.c
index 9a50168..939d687 100644
--- a/submodule.c
+++ b/submodule.c
@@ -96,7 +96,7 @@
 	if (is_gitmodules_unmerged(&the_index))
 		die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
 
-	submodule = submodule_from_path(&null_oid, oldpath);
+	submodule = submodule_from_path(the_repository, &null_oid, oldpath);
 	if (!submodule || !submodule->name) {
 		warning(_("Could not find section in .gitmodules where path=%s"), oldpath);
 		return -1;
@@ -130,7 +130,7 @@
 	if (is_gitmodules_unmerged(&the_index))
 		die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
 
-	submodule = submodule_from_path(&null_oid, path);
+	submodule = submodule_from_path(the_repository, &null_oid, path);
 	if (!submodule || !submodule->name) {
 		warning(_("Could not find section in .gitmodules where path=%s"), path);
 		return -1;
@@ -153,7 +153,8 @@
 		die(_("staging updated .gitmodules failed"));
 }
 
-static int add_submodule_odb(const char *path)
+/* TODO: remove this function, use repo_submodule_init instead. */
+int add_submodule_odb(const char *path)
 {
 	struct strbuf objects_directory = STRBUF_INIT;
 	int ret = 0;
@@ -174,7 +175,8 @@
 void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 					     const char *path)
 {
-	const struct submodule *submodule = submodule_from_path(&null_oid, path);
+	const struct submodule *submodule = submodule_from_path(the_repository,
+								&null_oid, path);
 	if (submodule) {
 		const char *ignore;
 		char *key;
@@ -230,7 +232,7 @@
 	const struct string_list *sl;
 	const struct submodule *module;
 
-	module = submodule_from_cache(repo, &null_oid, path);
+	module = submodule_from_path(repo, &null_oid, path);
 
 	/* early return if there isn't a path->module mapping */
 	if (!module)
@@ -674,7 +676,7 @@
 	if (!should_update_submodules())
 		return NULL;
 
-	return submodule_from_path(&null_oid, ce->name);
+	return submodule_from_path(the_repository, &null_oid, ce->name);
 }
 
 static struct oid_array *submodule_commits(struct string_list *submodules,
@@ -731,13 +733,14 @@
 		if (!S_ISGITLINK(p->two->mode))
 			continue;
 
-		submodule = submodule_from_path(commit_oid, p->two->path);
+		submodule = submodule_from_path(the_repository,
+						commit_oid, p->two->path);
 		if (submodule)
 			name = submodule->name;
 		else {
 			name = default_name_or_path(p->two->path);
 			/* make sure name does not collide with existing one */
-			submodule = submodule_from_name(commit_oid, name);
+			submodule = submodule_from_name(the_repository, commit_oid, name);
 			if (submodule) {
 				warning("Submodule in commit %s at path: "
 					"'%s' collides with a submodule named "
@@ -818,7 +821,7 @@
 {
 	struct has_commit_data *cb = data;
 
-	enum object_type type = oid_object_info(oid, NULL);
+	enum object_type type = oid_object_info(the_repository, oid, NULL);
 
 	switch (type) {
 	case OBJ_COMMIT:
@@ -945,7 +948,7 @@
 		const struct submodule *submodule;
 		const char *path = NULL;
 
-		submodule = submodule_from_name(&null_oid, name->string);
+		submodule = submodule_from_name(the_repository, &null_oid, name->string);
 		if (submodule)
 			path = submodule->path;
 		else
@@ -966,7 +969,7 @@
 
 static int push_submodule(const char *path,
 			  const struct remote *remote,
-			  const char **refspec, int refspec_nr,
+			  const struct refspec *rs,
 			  const struct string_list *push_options,
 			  int dry_run)
 {
@@ -989,8 +992,8 @@
 		if (remote->origin != REMOTE_UNCONFIGURED) {
 			int i;
 			argv_array_push(&cp.args, remote->name);
-			for (i = 0; i < refspec_nr; i++)
-				argv_array_push(&cp.args, refspec[i]);
+			for (i = 0; i < rs->raw_nr; i++)
+				argv_array_push(&cp.args, rs->raw[i]);
 		}
 
 		prepare_submodule_repo_env(&cp.env_array);
@@ -1011,7 +1014,7 @@
  */
 static void submodule_push_check(const char *path, const char *head,
 				 const struct remote *remote,
-				 const char **refspec, int refspec_nr)
+				 const struct refspec *rs)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 	int i;
@@ -1021,8 +1024,8 @@
 	argv_array_push(&cp.args, head);
 	argv_array_push(&cp.args, remote->name);
 
-	for (i = 0; i < refspec_nr; i++)
-		argv_array_push(&cp.args, refspec[i]);
+	for (i = 0; i < rs->raw_nr; i++)
+		argv_array_push(&cp.args, rs->raw[i]);
 
 	prepare_submodule_repo_env(&cp.env_array);
 	cp.git_cmd = 1;
@@ -1041,7 +1044,7 @@
 
 int push_unpushed_submodules(struct oid_array *commits,
 			     const struct remote *remote,
-			     const char **refspec, int refspec_nr,
+			     const struct refspec *rs,
 			     const struct string_list *push_options,
 			     int dry_run)
 {
@@ -1067,8 +1070,7 @@
 
 		for (i = 0; i < needs_pushing.nr; i++)
 			submodule_push_check(needs_pushing.items[i].string,
-					     head, remote,
-					     refspec, refspec_nr);
+					     head, remote, rs);
 		free(head);
 	}
 
@@ -1076,7 +1078,7 @@
 	for (i = 0; i < needs_pushing.nr; i++) {
 		const char *path = needs_pushing.items[i].string;
 		fprintf(stderr, "Pushing submodule '%s'\n", path);
-		if (!push_submodule(path, remote, refspec, refspec_nr,
+		if (!push_submodule(path, remote, rs,
 				    push_options, dry_run)) {
 			fprintf(stderr, "Unable to push submodule '%s'\n", path);
 			ret = 0;
@@ -1113,7 +1115,7 @@
 	const struct string_list_item *name;
 
 	/* No need to check if there are no submodules configured */
-	if (!submodule_from_path(NULL, NULL))
+	if (!submodule_from_path(the_repository, NULL, NULL))
 		return;
 
 	argv_array_push(&argv, "--"); /* argv[0] program name */
@@ -1134,7 +1136,7 @@
 		const struct submodule *submodule;
 		const char *path = NULL;
 
-		submodule = submodule_from_name(&null_oid, name->string);
+		submodule = submodule_from_name(the_repository, &null_oid, name->string);
 		if (submodule)
 			path = submodule->path;
 		else
@@ -1162,13 +1164,15 @@
 	int ret;
 
 	/* No need to check if there are no submodules configured */
-	if (!submodule_from_path(NULL, NULL))
+	if (!submodule_from_path(the_repository, NULL, NULL))
 		return 0;
 
 	argv_array_push(&args, "--"); /* args[0] program name */
 	argv_array_push(&args, oid_to_hex(incl_oid));
-	argv_array_push(&args, "--not");
-	argv_array_push(&args, oid_to_hex(excl_oid));
+	if (!is_null_oid(excl_oid)) {
+		argv_array_push(&args, "--not");
+		argv_array_push(&args, oid_to_hex(excl_oid));
+	}
 
 	collect_changed_submodules(&subs, &args);
 	ret = subs.nr;
@@ -1234,7 +1238,7 @@
 		if (!S_ISGITLINK(ce->ce_mode))
 			continue;
 
-		submodule = submodule_from_cache(spf->r, &null_oid, ce->name);
+		submodule = submodule_from_path(spf->r, &null_oid, ce->name);
 		if (!submodule) {
 			const char *name = default_name_or_path(ce->name);
 			if (name) {
@@ -1398,7 +1402,7 @@
 		    buf.buf[0] == '2') {
 			/* T = line type, XY = status, SSSS = submodule state */
 			if (buf.len < strlen("T XY SSSS"))
-				die("BUG: invalid status --porcelain=2 line %s",
+				BUG("invalid status --porcelain=2 line %s",
 				    buf.buf);
 
 			if (buf.buf[5] == 'S' && buf.buf[8] == 'U')
@@ -1567,7 +1571,7 @@
 				   get_super_prefix_or_empty(), path);
 	argv_array_pushl(&cp.args, "read-tree", "-u", "--reset", NULL);
 
-	argv_array_push(&cp.args, EMPTY_TREE_SHA1_HEX);
+	argv_array_push(&cp.args, empty_tree_oid_hex());
 
 	if (run_command(&cp))
 		die("could not reset submodule index");
@@ -1604,10 +1608,10 @@
 	if (old_head && !is_submodule_populated_gently(path, error_code_ptr))
 		return 0;
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(the_repository, &null_oid, path);
 
 	if (!sub)
-		die("BUG: could not get submodule information for '%s'", path);
+		BUG("could not get submodule information for '%s'", path);
 
 	if (old_head && !(flags & SUBMODULE_MOVE_HEAD_FORCE)) {
 		/* Check if the submodule has a dirty index. */
@@ -1623,7 +1627,7 @@
 		} else {
 			char *gitdir = xstrfmt("%s/modules/%s",
 				    get_git_common_dir(), sub->name);
-			connect_work_tree_and_git_dir(path, gitdir);
+			connect_work_tree_and_git_dir(path, gitdir, 0);
 			free(gitdir);
 
 			/* make sure the index is clean as well */
@@ -1633,7 +1637,7 @@
 		if (old_head && (flags & SUBMODULE_MOVE_HEAD_FORCE)) {
 			char *gitdir = xstrfmt("%s/modules/%s",
 				    get_git_common_dir(), sub->name);
-			connect_work_tree_and_git_dir(path, gitdir);
+			connect_work_tree_and_git_dir(path, gitdir, 1);
 			free(gitdir);
 		}
 	}
@@ -1659,9 +1663,9 @@
 		argv_array_push(&cp.args, "-m");
 
 	if (!(flags & SUBMODULE_MOVE_HEAD_FORCE))
-		argv_array_push(&cp.args, old_head ? old_head : EMPTY_TREE_SHA1_HEX);
+		argv_array_push(&cp.args, old_head ? old_head : empty_tree_oid_hex());
 
-	argv_array_push(&cp.args, new_head ? new_head : EMPTY_TREE_SHA1_HEX);
+	argv_array_push(&cp.args, new_head ? new_head : empty_tree_oid_hex());
 
 	if (run_command(&cp)) {
 		ret = -1;
@@ -1699,171 +1703,6 @@
 	return ret;
 }
 
-static int find_first_merges(struct object_array *result, const char *path,
-		struct commit *a, struct commit *b)
-{
-	int i, j;
-	struct object_array merges = OBJECT_ARRAY_INIT;
-	struct commit *commit;
-	int contains_another;
-
-	char merged_revision[42];
-	const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
-				   "--all", merged_revision, NULL };
-	struct rev_info revs;
-	struct setup_revision_opt rev_opts;
-
-	memset(result, 0, sizeof(struct object_array));
-	memset(&rev_opts, 0, sizeof(rev_opts));
-
-	/* get all revisions that merge commit a */
-	xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
-			oid_to_hex(&a->object.oid));
-	init_revisions(&revs, NULL);
-	rev_opts.submodule = path;
-	/* FIXME: can't handle linked worktrees in submodules yet */
-	revs.single_worktree = path != NULL;
-	setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);
-
-	/* save all revisions from the above list that contain b */
-	if (prepare_revision_walk(&revs))
-		die("revision walk setup failed");
-	while ((commit = get_revision(&revs)) != NULL) {
-		struct object *o = &(commit->object);
-		if (in_merge_bases(b, commit))
-			add_object_array(o, NULL, &merges);
-	}
-	reset_revision_walk();
-
-	/* Now we've got all merges that contain a and b. Prune all
-	 * merges that contain another found merge and save them in
-	 * result.
-	 */
-	for (i = 0; i < merges.nr; i++) {
-		struct commit *m1 = (struct commit *) merges.objects[i].item;
-
-		contains_another = 0;
-		for (j = 0; j < merges.nr; j++) {
-			struct commit *m2 = (struct commit *) merges.objects[j].item;
-			if (i != j && in_merge_bases(m2, m1)) {
-				contains_another = 1;
-				break;
-			}
-		}
-
-		if (!contains_another)
-			add_object_array(merges.objects[i].item, NULL, result);
-	}
-
-	object_array_clear(&merges);
-	return result->nr;
-}
-
-static void print_commit(struct commit *commit)
-{
-	struct strbuf sb = STRBUF_INIT;
-	struct pretty_print_context ctx = {0};
-	ctx.date_mode.type = DATE_NORMAL;
-	format_commit_message(commit, " %h: %m %s", &sb, &ctx);
-	fprintf(stderr, "%s\n", sb.buf);
-	strbuf_release(&sb);
-}
-
-#define MERGE_WARNING(path, msg) \
-	warning("Failed to merge submodule %s (%s)", path, msg);
-
-int merge_submodule(struct object_id *result, const char *path,
-		    const struct object_id *base, const struct object_id *a,
-		    const struct object_id *b, int search)
-{
-	struct commit *commit_base, *commit_a, *commit_b;
-	int parent_count;
-	struct object_array merges;
-
-	int i;
-
-	/* store a in result in case we fail */
-	oidcpy(result, a);
-
-	/* we can not handle deletion conflicts */
-	if (is_null_oid(base))
-		return 0;
-	if (is_null_oid(a))
-		return 0;
-	if (is_null_oid(b))
-		return 0;
-
-	if (add_submodule_odb(path)) {
-		MERGE_WARNING(path, "not checked out");
-		return 0;
-	}
-
-	if (!(commit_base = lookup_commit_reference(base)) ||
-	    !(commit_a = lookup_commit_reference(a)) ||
-	    !(commit_b = lookup_commit_reference(b))) {
-		MERGE_WARNING(path, "commits not present");
-		return 0;
-	}
-
-	/* check whether both changes are forward */
-	if (!in_merge_bases(commit_base, commit_a) ||
-	    !in_merge_bases(commit_base, commit_b)) {
-		MERGE_WARNING(path, "commits don't follow merge-base");
-		return 0;
-	}
-
-	/* Case #1: a is contained in b or vice versa */
-	if (in_merge_bases(commit_a, commit_b)) {
-		oidcpy(result, b);
-		return 1;
-	}
-	if (in_merge_bases(commit_b, commit_a)) {
-		oidcpy(result, a);
-		return 1;
-	}
-
-	/*
-	 * Case #2: There are one or more merges that contain a and b in
-	 * the submodule. If there is only one, then present it as a
-	 * suggestion to the user, but leave it marked unmerged so the
-	 * user needs to confirm the resolution.
-	 */
-
-	/* Skip the search if makes no sense to the calling context.  */
-	if (!search)
-		return 0;
-
-	/* find commit which merges them */
-	parent_count = find_first_merges(&merges, path, commit_a, commit_b);
-	switch (parent_count) {
-	case 0:
-		MERGE_WARNING(path, "merge following commits not found");
-		break;
-
-	case 1:
-		MERGE_WARNING(path, "not fast-forward");
-		fprintf(stderr, "Found a possible merge resolution "
-				"for the submodule:\n");
-		print_commit((struct commit *) merges.objects[0].item);
-		fprintf(stderr,
-			"If this is correct simply add it to the index "
-			"for example\n"
-			"by using:\n\n"
-			"  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
-			"which will accept this suggestion.\n",
-			oid_to_hex(&merges.objects[0].item->oid), path);
-		break;
-
-	default:
-		MERGE_WARNING(path, "multiple merges found");
-		for (i = 0; i < merges.nr; i++)
-			print_commit((struct commit *) merges.objects[i].item);
-	}
-
-	object_array_clear(&merges);
-	return 0;
-}
-
 /*
  * Embeds a single submodules git directory into the superprojects git dir,
  * non recursively.
@@ -1886,7 +1725,7 @@
 
 	real_old_git_dir = real_pathdup(old_git_dir, 1);
 
-	sub = submodule_from_path(&null_oid, path);
+	sub = submodule_from_path(the_repository, &null_oid, path);
 	if (!sub)
 		die(_("could not lookup name for submodule '%s'"), path);
 
@@ -1942,11 +1781,11 @@
 		* superproject did not rewrite the git file links yet,
 		* fix it now.
 		*/
-		sub = submodule_from_path(&null_oid, path);
+		sub = submodule_from_path(the_repository, &null_oid, path);
 		if (!sub)
 			die(_("could not lookup name for submodule '%s'"), path);
 		connect_work_tree_and_git_dir(path,
-			git_path("modules/%s", sub->name));
+			git_path("modules/%s", sub->name), 0);
 	} else {
 		/* Is it already absorbed into the superprojects git dir? */
 		char *real_sub_git_dir = real_pathdup(sub_git_dir, 1);
@@ -1965,7 +1804,7 @@
 		struct strbuf sb = STRBUF_INIT;
 
 		if (flags & ~ABSORB_GITDIR_RECURSE_SUBMODULES)
-			die("BUG: we don't know how to pass the flags down?");
+			BUG("we don't know how to pass the flags down?");
 
 		strbuf_addstr(&sb, get_super_prefix_or_empty());
 		strbuf_addstr(&sb, path);
@@ -2043,7 +1882,7 @@
 
 		if (super_sub_len > cwd_len ||
 		    strcmp(&cwd[cwd_len - super_sub_len], super_sub))
-			die (_("BUG: returned path string doesn't match cwd?"));
+			BUG("returned path string doesn't match cwd?");
 
 		super_wt = xstrdup(cwd);
 		super_wt[cwd_len - super_sub_len] = '\0';
@@ -2088,7 +1927,7 @@
 		strbuf_addstr(buf, git_dir);
 	}
 	if (!is_git_directory(buf->buf)) {
-		sub = submodule_from_path(&null_oid, submodule);
+		sub = submodule_from_path(the_repository, &null_oid, submodule);
 		if (!sub) {
 			ret = -1;
 			goto cleanup;
diff --git a/submodule.h b/submodule.h
index 9589f13..7856b8a 100644
--- a/submodule.h
+++ b/submodule.h
@@ -89,23 +89,24 @@
 #define SUBMODULE_REMOVAL_IGNORE_UNTRACKED (1<<1)
 #define SUBMODULE_REMOVAL_IGNORE_IGNORED_UNTRACKED (1<<2)
 extern int bad_to_remove_submodule(const char *path, unsigned flags);
-extern int merge_submodule(struct object_id *result, const char *path,
-			   const struct object_id *base,
-			   const struct object_id *a,
-			   const struct object_id *b, int search);
 
-/* Checks if there are submodule changes in a..b. */
+int add_submodule_odb(const char *path);
+
+/*
+ * Checks if there are submodule changes in a..b. If a is the null OID,
+ * checks b and all its ancestors instead.
+ */
 extern int submodule_touches_in_range(struct object_id *a,
 				      struct object_id *b);
 extern int find_unpushed_submodules(struct oid_array *commits,
 				    const char *remotes_name,
 				    struct string_list *needs_pushing);
+struct refspec;
 extern int push_unpushed_submodules(struct oid_array *commits,
 				    const struct remote *remote,
-				    const char **refspec, int refspec_nr,
+				    const struct refspec *rs,
 				    const struct string_list *push_options,
 				    int dry_run);
-extern void connect_work_tree_and_git_dir(const char *work_tree, const char *git_dir);
 /*
  * Given a submodule path (as in the index), return the repository
  * path of that submodule in 'buf'. Return -1 on error or when the
diff --git a/t/README b/t/README
index 24ddebf..8373a27 100644
--- a/t/README
+++ b/t/README
@@ -293,6 +293,28 @@
 everything up to a certain test.
 
 
+Running tests with special setups
+---------------------------------
+
+The whole test suite could be run to test some special features
+that cannot be easily covered by a few specific test cases. These
+could be enabled by running the test suite with correct GIT_TEST_
+environment set.
+
+GIT_TEST_SPLIT_INDEX=<boolean> forces split-index mode on the whole
+test suite. Accept any boolean values that are accepted by git-config.
+
+GIT_TEST_FULL_IN_PACK_ARRAY=<boolean> exercises the uncommon
+pack-objects code path where there are more than 1024 packs even if
+the actual number of packs in repository is below this limit. Accept
+any boolean values that are accepted by git-config.
+
+GIT_TEST_OE_SIZE=<n> exercises the uncommon pack-objects code path
+where we do not cache object size in memory and read it from existing
+packs on demand. This normally only happens when the object size is
+over 2GB. This variable forces the code path on any object larger than
+<n> bytes.
+
 Naming Tests
 ------------
 
diff --git a/t/diff-lib.sh b/t/diff-lib.sh
index c211dc4..2de880f 100644
--- a/t/diff-lib.sh
+++ b/t/diff-lib.sh
@@ -1,6 +1,6 @@
 :
 
-sanitize_diff_raw='/^:/s/ '"\($_x40\)"' '"\($_x40\)"' \([A-Z]\)[0-9]*	/ \1 \2 \3#	/'
+sanitize_diff_raw='/^:/s/ '"\($OID_REGEX\)"' '"\($OID_REGEX\)"' \([A-Z]\)[0-9]*	/ \1 \2 \3#	/'
 compare_diff_raw () {
     # When heuristics are improved, the score numbers would change.
     # Ignore them while comparing.
@@ -12,7 +12,7 @@
     test_cmp .tmp-1 .tmp-2 && rm -f .tmp-1 .tmp-2
 }
 
-sanitize_diff_raw_z='/^:/s/ '"$_x40"' '"$_x40"' \([A-Z]\)[0-9]*$/ X X \1#/'
+sanitize_diff_raw_z='/^:/s/ '"$OID_REGEX"' '"$OID_REGEX"' \([A-Z]\)[0-9]*$/ X X \1#/'
 compare_diff_raw_z () {
     # When heuristics are improved, the score numbers would change.
     # Ignore them while comparing.
diff --git a/t/helper/test-drop-caches.c b/t/helper/test-drop-caches.c
index 8387608..d6bcfdd 100644
--- a/t/helper/test-drop-caches.c
+++ b/t/helper/test-drop-caches.c
@@ -2,6 +2,7 @@
 #include "git-compat-util.h"
 
 #if defined(GIT_WINDOWS_NATIVE)
+#include "lazyload.h"
 
 static int cmd_sync(void)
 {
@@ -82,8 +83,7 @@
 {
 	HANDLE hProcess = GetCurrentProcess();
 	HANDLE hToken;
-	HMODULE ntdll;
-	DWORD(WINAPI *NtSetSystemInformation)(INT, PVOID, ULONG);
+	DECLARE_PROC_ADDR(ntdll.dll, DWORD, NtSetSystemInformation, INT, PVOID, ULONG);
 	SYSTEM_MEMORY_LIST_COMMAND command;
 	int status;
 
@@ -95,14 +95,8 @@
 
 	CloseHandle(hToken);
 
-	ntdll = LoadLibrary("ntdll.dll");
-	if (!ntdll)
-		return error("Can't load ntdll.dll, wrong Windows version?");
-
-	NtSetSystemInformation =
-		(DWORD(WINAPI *)(INT, PVOID, ULONG))GetProcAddress(ntdll, "NtSetSystemInformation");
-	if (!NtSetSystemInformation)
-		return error("Can't get function addresses, wrong Windows version?");
+	if (!INIT_PROC_ADDR(NtSetSystemInformation))
+		return error("Could not find NtSetSystemInformation() function");
 
 	command = MemoryPurgeStandbyList;
 	status = NtSetSystemInformation(
@@ -115,8 +109,6 @@
 	else if (status != STATUS_SUCCESS)
 		error("Unable to execute the memory list command %d", status);
 
-	FreeLibrary(ntdll);
-
 	return status;
 }
 
diff --git a/t/helper/test-dump-split-index.c b/t/helper/test-dump-split-index.c
index 4e2fdb5..63c689d 100644
--- a/t/helper/test-dump-split-index.c
+++ b/t/helper/test-dump-split-index.c
@@ -14,13 +14,13 @@
 	int i;
 
 	do_read_index(&the_index, av[1], 1);
-	printf("own %s\n", sha1_to_hex(the_index.sha1));
+	printf("own %s\n", oid_to_hex(&the_index.oid));
 	si = the_index.split_index;
 	if (!si) {
 		printf("not a split index\n");
 		return 0;
 	}
-	printf("base %s\n", sha1_to_hex(si->base_sha1));
+	printf("base %s\n", oid_to_hex(&si->base_oid));
 	for (i = 0; i < the_index.cache_nr; i++) {
 		struct cache_entry *ce = the_index.cache[i];
 		printf("%06o %s %d\t%s\n", ce->ce_mode,
diff --git a/t/helper/test-dump-untracked-cache.c b/t/helper/test-dump-untracked-cache.c
index d7c55c2..bd92fb3 100644
--- a/t/helper/test-dump-untracked-cache.c
+++ b/t/helper/test-dump-untracked-cache.c
@@ -23,7 +23,7 @@
 	len = base->len;
 	strbuf_addf(base, "%s/", ucd->name);
 	printf("%s %s", base->buf,
-	       sha1_to_hex(ucd->exclude_sha1));
+	       oid_to_hex(&ucd->exclude_oid));
 	if (ucd->recurse)
 		fputs(" recurse", stdout);
 	if (ucd->check_only)
diff --git a/t/helper/test-example-decorate.c b/t/helper/test-example-decorate.c
index 081115b..a20a616 100644
--- a/t/helper/test-example-decorate.c
+++ b/t/helper/test-example-decorate.c
@@ -30,10 +30,10 @@
 	two = lookup_unknown_object(two_oid.hash);
 	ret = add_decoration(&n, one, &decoration_a);
 	if (ret)
-		die("BUG: when adding a brand-new object, NULL should be returned");
+		BUG("when adding a brand-new object, NULL should be returned");
 	ret = add_decoration(&n, two, NULL);
 	if (ret)
-		die("BUG: when adding a brand-new object, NULL should be returned");
+		BUG("when adding a brand-new object, NULL should be returned");
 
 	/*
 	 * When re-adding an already existing object, the old decoration is
@@ -41,10 +41,10 @@
 	 */
 	ret = add_decoration(&n, one, NULL);
 	if (ret != &decoration_a)
-		die("BUG: when readding an already existing object, existing decoration should be returned");
+		BUG("when readding an already existing object, existing decoration should be returned");
 	ret = add_decoration(&n, two, &decoration_b);
 	if (ret)
-		die("BUG: when readding an already existing object, existing decoration should be returned");
+		BUG("when readding an already existing object, existing decoration should be returned");
 
 	/*
 	 * Lookup returns the added declarations, or NULL if the object was
@@ -52,14 +52,14 @@
 	 */
 	ret = lookup_decoration(&n, one);
 	if (ret)
-		die("BUG: lookup should return added declaration");
+		BUG("lookup should return added declaration");
 	ret = lookup_decoration(&n, two);
 	if (ret != &decoration_b)
-		die("BUG: lookup should return added declaration");
+		BUG("lookup should return added declaration");
 	three = lookup_unknown_object(three_oid.hash);
 	ret = lookup_decoration(&n, three);
 	if (ret)
-		die("BUG: lookup for unknown object should return NULL");
+		BUG("lookup for unknown object should return NULL");
 
 	/*
 	 * The user can also loop through all entries.
@@ -69,7 +69,7 @@
 			objects_noticed++;
 	}
 	if (objects_noticed != 2)
-		die("BUG: should have 2 objects");
+		BUG("should have 2 objects");
 
 	return 0;
 }
diff --git a/t/helper/test-path-utils.c b/t/helper/test-path-utils.c
index e115d44..ae091d9 100644
--- a/t/helper/test-path-utils.c
+++ b/t/helper/test-path-utils.c
@@ -1,6 +1,7 @@
 #include "test-tool.h"
 #include "cache.h"
 #include "string-list.h"
+#include "utf8.h"
 
 /*
  * A "string_list_each_func_t" function that normalizes an entry from
@@ -171,6 +172,11 @@
 	{ NULL,              NULL     }
 };
 
+static int is_dotgitmodules(const char *path)
+{
+	return is_hfs_dotgitmodules(path) || is_ntfs_dotgitmodules(path);
+}
+
 int cmd__path_utils(int argc, const char **argv)
 {
 	if (argc == 3 && !strcmp(argv[1], "normalize_path_copy")) {
@@ -271,6 +277,20 @@
 	if (argc == 2 && !strcmp(argv[1], "dirname"))
 		return test_function(dirname_data, posix_dirname, argv[1]);
 
+	if (argc > 2 && !strcmp(argv[1], "is_dotgitmodules")) {
+		int res = 0, expect = 1, i;
+		for (i = 2; i < argc; i++)
+			if (!strcmp("--not", argv[i]))
+				expect = !expect;
+			else if (expect != is_dotgitmodules(argv[i]))
+				res = error("'%s' is %s.gitmodules", argv[i],
+					    expect ? "not " : "");
+			else
+				fprintf(stderr, "ok: '%s' is %s.gitmodules\n",
+					argv[i], expect ? "" : "not ");
+		return !!res;
+	}
+
 	fprintf(stderr, "%s: unknown function name: %s\n", argv[0],
 		argv[1] ? argv[1] : "(there was none)");
 	return 1;
diff --git a/t/helper/test-pkt-line.c b/t/helper/test-pkt-line.c
new file mode 100644
index 0000000..0f19e53
--- /dev/null
+++ b/t/helper/test-pkt-line.c
@@ -0,0 +1,64 @@
+#include "pkt-line.h"
+
+static void pack_line(const char *line)
+{
+	if (!strcmp(line, "0000") || !strcmp(line, "0000\n"))
+		packet_flush(1);
+	else if (!strcmp(line, "0001") || !strcmp(line, "0001\n"))
+		packet_delim(1);
+	else
+		packet_write_fmt(1, "%s", line);
+}
+
+static void pack(int argc, const char **argv)
+{
+	if (argc) { /* read from argv */
+		int i;
+		for (i = 0; i < argc; i++)
+			pack_line(argv[i]);
+	} else { /* read from stdin */
+		char line[LARGE_PACKET_MAX];
+		while (fgets(line, sizeof(line), stdin)) {
+			pack_line(line);
+		}
+	}
+}
+
+static void unpack(void)
+{
+	struct packet_reader reader;
+	packet_reader_init(&reader, 0, NULL, 0,
+			   PACKET_READ_GENTLE_ON_EOF |
+			   PACKET_READ_CHOMP_NEWLINE);
+
+	while (packet_reader_read(&reader) != PACKET_READ_EOF) {
+		switch (reader.status) {
+		case PACKET_READ_EOF:
+			break;
+		case PACKET_READ_NORMAL:
+			printf("%s\n", reader.line);
+			break;
+		case PACKET_READ_FLUSH:
+			printf("0000\n");
+			break;
+		case PACKET_READ_DELIM:
+			printf("0001\n");
+			break;
+		}
+	}
+}
+
+int cmd_main(int argc, const char **argv)
+{
+	if (argc < 2)
+		die("too few arguments");
+
+	if (!strcmp(argv[1], "pack"))
+		pack(argc - 2, argv + 2);
+	else if (!strcmp(argv[1], "unpack"))
+		unpack();
+	else
+		die("invalid argument '%s'", argv[1]);
+
+	return 0;
+}
diff --git a/t/helper/test-ref-store.c b/t/helper/test-ref-store.c
index 7c4f437..e9e0541 100644
--- a/t/helper/test-ref-store.c
+++ b/t/helper/test-ref-store.c
@@ -3,6 +3,7 @@
 #include "refs.h"
 #include "worktree.h"
 #include "object-store.h"
+#include "repository.h"
 
 static const char *notnull(const char *arg, const char *name)
 {
@@ -23,7 +24,7 @@
 	if (!argv[0]) {
 		die("ref store required");
 	} else if (!strcmp(argv[0], "main")) {
-		*refs = get_main_ref_store();
+		*refs = get_main_ref_store(the_repository);
 	} else if (skip_prefix(argv[0], "submodule:", &gitdir)) {
 		struct strbuf sb = STRBUF_INIT;
 		int ret;
diff --git a/t/helper/test-scrap-cache-tree.c b/t/helper/test-scrap-cache-tree.c
index d26d3e7..393f160 100644
--- a/t/helper/test-scrap-cache-tree.c
+++ b/t/helper/test-scrap-cache-tree.c
@@ -4,10 +4,10 @@
 #include "tree.h"
 #include "cache-tree.h"
 
-static struct lock_file index_lock;
-
 int cmd__scrap_cache_tree(int ac, const char **av)
 {
+	struct lock_file index_lock = LOCK_INIT;
+
 	setup_git_directory();
 	hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
 	if (read_cache() < 0)
diff --git a/t/helper/test-submodule-config.c b/t/helper/test-submodule-config.c
index 5c6e4b0..e269274 100644
--- a/t/helper/test-submodule-config.c
+++ b/t/helper/test-submodule-config.c
@@ -49,9 +49,11 @@
 			die_usage(argc, argv, "Commit not found.");
 
 		if (lookup_name) {
-			submodule = submodule_from_name(&commit_oid, path_or_name);
+			submodule = submodule_from_name(the_repository,
+							&commit_oid, path_or_name);
 		} else
-			submodule = submodule_from_path(&commit_oid, path_or_name);
+			submodule = submodule_from_path(the_repository,
+							&commit_oid, path_or_name);
 		if (!submodule)
 			die_usage(argc, argv, "Submodule not found.");
 
@@ -65,7 +67,7 @@
 		arg += 2;
 	}
 
-	submodule_free();
+	submodule_free(the_repository);
 
 	return 0;
 }
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 87066ce..805a45d 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -48,6 +48,7 @@
 {
 	int i;
 
+	BUG_exit_code = 99;
 	if (argc < 2)
 		die("I need a test name!");
 
diff --git a/t/helper/test-write-cache.c b/t/helper/test-write-cache.c
index 017dc30..8837717 100644
--- a/t/helper/test-write-cache.c
+++ b/t/helper/test-write-cache.c
@@ -2,22 +2,18 @@
 #include "cache.h"
 #include "lockfile.h"
 
-static struct lock_file index_lock;
-
 int cmd__write_cache(int argc, const char **argv)
 {
-	int i, cnt = 1, lockfd;
+	struct lock_file index_lock = LOCK_INIT;
+	int i, cnt = 1;
 	if (argc == 2)
 		cnt = strtol(argv[1], NULL, 0);
 	setup_git_directory();
 	read_cache();
 	for (i = 0; i < cnt; i++) {
-		lockfd = hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
-		if (0 <= lockfd) {
-			write_locked_index(&the_index, &index_lock, COMMIT_LOCK);
-		} else {
-			rollback_lock_file(&index_lock);
-		}
+		hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
+		if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
+			die("unable to write index file");
 	}
 
 	return 0;
diff --git a/t/lib-diff-alternative.sh b/t/lib-diff-alternative.sh
index 8b4dbf2..8d1e408 100644
--- a/t/lib-diff-alternative.sh
+++ b/t/lib-diff-alternative.sh
@@ -59,9 +59,11 @@
 }
 EOF
 
-	cat >expect <<\EOF
+	file1=$(git rev-parse --short $(git hash-object file1))
+	file2=$(git rev-parse --short $(git hash-object file2))
+	cat >expect <<EOF
 diff --git a/file1 b/file2
-index 6faa5a3..e3af329 100644
+index $file1..$file2 100644
 --- a/file1
 +++ b/file2
 @@ -1,26 +1,25 @@
@@ -136,9 +138,11 @@
 f
 EOF
 
-	cat >expect <<\EOF
+	uniq1=$(git rev-parse --short $(git hash-object uniq1))
+	uniq2=$(git rev-parse --short $(git hash-object uniq2))
+	cat >expect <<EOF
 diff --git a/uniq1 b/uniq2
-index b414108..0fdf397 100644
+index $uniq1..$uniq2 100644
 --- a/uniq1
 +++ b/uniq2
 @@ -1,6 +1,6 @@
diff --git a/t/lib-pack.sh b/t/lib-pack.sh
index 5010782..c4d907a 100644
--- a/t/lib-pack.sh
+++ b/t/lib-pack.sh
@@ -79,6 +79,18 @@
 		;;
 	esac
 
+	# If it's not a delta, we can convince pack-objects to generate a pack
+	# with just our entry, and then strip off the header (12 bytes) and
+	# trailer (20 bytes).
+	if test -z "$2"
+	then
+		echo "$1" | git pack-objects --stdout >pack_obj.tmp &&
+		size=$(wc -c <pack_obj.tmp) &&
+		dd if=pack_obj.tmp bs=1 count=$((size - 20 - 12)) skip=12 &&
+		rm -f pack_obj.tmp
+		return
+	fi
+
 	echo >&2 "BUG: don't know how to print $1${2:+ (from $2)}"
 	return 1
 }
diff --git a/t/lib-t6000.sh b/t/lib-t6000.sh
index 3f2d873..b0ed476 100644
--- a/t/lib-t6000.sh
+++ b/t/lib-t6000.sh
@@ -4,11 +4,11 @@
 
 >sed.script
 
-# Answer the sha1 has associated with the tag. The tag must exist in .git/refs/tags
+# Answer the sha1 has associated with the tag. The tag must exist under refs/tags
 tag () {
 	_tag=$1
-	test -f ".git/refs/tags/$_tag" || error "tag: \"$_tag\" does not exist"
-	cat ".git/refs/tags/$_tag"
+	git rev-parse --verify "refs/tags/$_tag" ||
+	error "tag: \"$_tag\" does not exist"
 }
 
 # Generate a commit using the text specified to make it unique and the tree
diff --git a/t/perf/aggregate.perl b/t/perf/aggregate.perl
index 48637ef..bc86516 100755
--- a/t/perf/aggregate.perl
+++ b/t/perf/aggregate.perl
@@ -4,6 +4,7 @@
 use strict;
 use warnings;
 use JSON;
+use Getopt::Long;
 use Git;
 
 sub get_times {
@@ -36,46 +37,34 @@
 	return $out;
 }
 
+sub usage {
+	print <<EOT;
+./aggregate.perl [options] [--] [<dir_or_rev>...] [--] [<test_script>...] >
+
+  Options:
+    --codespeed          * Format output for Codespeed
+    --reponame    <str>  * Send given reponame to codespeed
+    --sort-by     <str>  * Sort output (only "regression" criteria is supported)
+    --subsection  <str>  * Use results from given subsection
+
+EOT
+	exit(1);
+}
+
 my (@dirs, %dirnames, %dirabbrevs, %prefixes, @tests,
     $codespeed, $sortby, $subsection, $reponame);
+
+Getopt::Long::Configure qw/ require_order /;
+
+my $rc = GetOptions("codespeed"     => \$codespeed,
+		    "reponame=s"    => \$reponame,
+		    "sort-by=s"     => \$sortby,
+		    "subsection=s"  => \$subsection);
+usage() unless $rc;
+
 while (scalar @ARGV) {
 	my $arg = $ARGV[0];
 	my $dir;
-	if ($arg eq "--codespeed") {
-		$codespeed = 1;
-		shift @ARGV;
-		next;
-	}
-	if ($arg =~ /--sort-by(?:=(.*))?/) {
-		shift @ARGV;
-		if (defined $1) {
-			$sortby = $1;
-		} else {
-			$sortby = shift @ARGV;
-			if (! defined $sortby) {
-				die "'--sort-by' requires an argument";
-			}
-		}
-		next;
-	}
-	if ($arg eq "--subsection") {
-		shift @ARGV;
-		$subsection = $ARGV[0];
-		shift @ARGV;
-		if (! $subsection) {
-			die "empty subsection";
-		}
-		next;
-	}
-	if ($arg eq "--reponame") {
-		shift @ARGV;
-		$reponame = $ARGV[0];
-		shift @ARGV;
-		if (! $reponame) {
-			die "empty reponame";
-		}
-		next;
-	}
 	last if -f $arg or $arg eq "--";
 	if (! -d $arg) {
 		my $rev = Git::command_oneline(qw(rev-parse --verify), $arg);
@@ -225,7 +214,8 @@
 	my ($sortby) = @_;
 
 	if ($sortby ne "regression") {
-		die "only 'regression' is supported as '--sort-by' argument";
+		print "Only 'regression' is supported as '--sort-by' argument\n";
+		usage();
 	}
 
 	my @evolutions;
diff --git a/t/perf/bisect_run_script b/t/perf/bisect_run_script
index 038255d..3ebaf15 100755
--- a/t/perf/bisect_run_script
+++ b/t/perf/bisect_run_script
@@ -24,6 +24,12 @@
 GIT_PERF_DIRS_OR_REVS="$bisect_head"
 export GIT_PERF_DIRS_OR_REVS
 
+# Don't use codespeed
+GIT_PERF_CODESPEED_OUTPUT=
+GIT_PERF_SEND_TO_CODESPEED=
+export GIT_PERF_CODESPEED_OUTPUT
+export GIT_PERF_SEND_TO_CODESPEED
+
 ./run "$script" >"$result_file" 2>&1 || die "Failed to run perf test '$script'"
 
 rtime=$(sed -n "s/^$script_number\.$test_number:.*\([0-9]\+\.[0-9]\+\)(.*).*\$/\1/p" "$result_file")
diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index 7fd87dd..af61d08 100755
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh
@@ -839,7 +839,7 @@
 '
 
 # we know the shape and contents of the tree and know the object ID for it.
-test_expect_success 'validate object ID of a known tree' '
+test_expect_success SHA1 'validate object ID of a known tree' '
 	test "$tree" = 7bb943559a305bdd6bdee2cef6e5df2413c3d30a
     '
 
@@ -882,7 +882,7 @@
 	git ls-files --stage >current
 '
 
-test_expect_success 'validate git ls-files output for a known tree' '
+test_expect_success SHA1 'validate git ls-files output for a known tree' '
 	cat >expected <<-\EOF &&
 	100644 f87290f8eb2cbbea7857214459a0739927eab154 0	path0
 	120000 15a98433ae33114b085f3eb3bb03b832b3180a01 0	path0sym
@@ -900,7 +900,7 @@
 	tree=$(git write-tree)
 '
 
-test_expect_success 'validate object ID for a known tree' '
+test_expect_success SHA1 'validate object ID for a known tree' '
 	test "$tree" = 087704a96baf1c2d1c869a8b084481e121c88b5b
 '
 
@@ -908,7 +908,7 @@
     git ls-tree $tree >current
 '
 
-test_expect_success 'git ls-tree output for a known tree' '
+test_expect_success SHA1 'git ls-tree output for a known tree' '
 	cat >expected <<-\EOF &&
 	100644 blob f87290f8eb2cbbea7857214459a0739927eab154	path0
 	120000 blob 15a98433ae33114b085f3eb3bb03b832b3180a01	path0sym
@@ -924,7 +924,7 @@
 	git ls-tree -r $tree >current
 '
 
-test_expect_success 'git ls-tree -r output for a known tree' '
+test_expect_success SHA1 'git ls-tree -r output for a known tree' '
 	cat >expected <<-\EOF &&
 	100644 blob f87290f8eb2cbbea7857214459a0739927eab154	path0
 	120000 blob 15a98433ae33114b085f3eb3bb03b832b3180a01	path0sym
@@ -943,7 +943,7 @@
 	git ls-tree -r -t $tree >current
 '
 
-test_expect_success 'git ls-tree -r output for a known tree' '
+test_expect_success SHA1 'git ls-tree -r output for a known tree' '
 	cat >expected <<-\EOF &&
 	100644 blob f87290f8eb2cbbea7857214459a0739927eab154	path0
 	120000 blob 15a98433ae33114b085f3eb3bb03b832b3180a01	path0sym
@@ -964,7 +964,7 @@
 	ptree=$(git write-tree --prefix=path3)
 '
 
-test_expect_success 'validate object ID for a known tree' '
+test_expect_success SHA1 'validate object ID for a known tree' '
 	test "$ptree" = 21ae8269cacbe57ae09138dcc3a2887f904d02b3
 '
 
@@ -972,7 +972,7 @@
 	ptree=$(git write-tree --prefix=path3/subp3)
 '
 
-test_expect_success 'validate object ID for a known tree' '
+test_expect_success SHA1 'validate object ID for a known tree' '
 	test "$ptree" = 3c5e5399f3a333eddecce7a9b9465b63f65f51e2
 '
 
@@ -1006,7 +1006,7 @@
 	test "$newtree" = "$tree"
 '
 
-test_expect_success 'validate git diff-files output for a know cache/work tree state' '
+test_expect_success SHA1 'validate git diff-files output for a know cache/work tree state' '
 	cat >expected <<\EOF &&
 :100644 100644 f87290f8eb2cbbea7857214459a0739927eab154 0000000000000000000000000000000000000000 M	path0
 :120000 120000 15a98433ae33114b085f3eb3bb03b832b3180a01 0000000000000000000000000000000000000000 M	path0sym
@@ -1033,21 +1033,21 @@
 ################################################################
 P=087704a96baf1c2d1c869a8b084481e121c88b5b
 
-test_expect_success 'git commit-tree records the correct tree in a commit' '
+test_expect_success SHA1 'git commit-tree records the correct tree in a commit' '
 	commit0=$(echo NO | git commit-tree $P) &&
 	tree=$(git show --pretty=raw $commit0 |
 		 sed -n -e "s/^tree //p" -e "/^author /q") &&
 	test "z$tree" = "z$P"
 '
 
-test_expect_success 'git commit-tree records the correct parent in a commit' '
+test_expect_success SHA1 'git commit-tree records the correct parent in a commit' '
 	commit1=$(echo NO | git commit-tree $P -p $commit0) &&
 	parent=$(git show --pretty=raw $commit1 |
 		sed -n -e "s/^parent //p" -e "/^author /q") &&
 	test "z$commit0" = "z$parent"
 '
 
-test_expect_success 'git commit-tree omits duplicated parent in a commit' '
+test_expect_success SHA1 'git commit-tree omits duplicated parent in a commit' '
 	commit2=$(echo NO | git commit-tree $P -p $commit0 -p $commit0) &&
 	     parent=$(git show --pretty=raw $commit2 |
 		sed -n -e "s/^parent //p" -e "/^author /q" |
diff --git a/t/t0012-help.sh b/t/t0012-help.sh
index 487b92a..bc27df7 100755
--- a/t/t0012-help.sh
+++ b/t/t0012-help.sh
@@ -25,6 +25,15 @@
 	EOF
 '
 
+# make sure to exercise these code paths, the output is a bit tricky
+# to verify
+test_expect_success 'basic help commands' '
+	git help >/dev/null &&
+	git help -a >/dev/null &&
+	git help -g >/dev/null &&
+	git help -av >/dev/null
+'
+
 test_expect_success "works for commands and guides by default" '
 	configure_help &&
 	git help status &&
@@ -49,8 +58,23 @@
 	test_i18ncmp expect actual
 "
 
+test_expect_success 'git help' '
+	git help >help.output &&
+	test_i18ngrep "^   clone  " help.output &&
+	test_i18ngrep "^   add    " help.output &&
+	test_i18ngrep "^   log    " help.output &&
+	test_i18ngrep "^   commit " help.output &&
+	test_i18ngrep "^   fetch  " help.output
+'
+test_expect_success 'git help -g' '
+	git help -g >help.output &&
+	test_i18ngrep "^   attributes " help.output &&
+	test_i18ngrep "^   everyday   " help.output &&
+	test_i18ngrep "^   tutorial   " help.output
+'
+
 test_expect_success 'generate builtin list' '
-	git --list-builtins >builtins
+	git --list-cmds=builtins >builtins
 '
 
 while read builtin
diff --git a/t/t0028-working-tree-encoding.sh b/t/t0028-working-tree-encoding.sh
new file mode 100755
index 0000000..12b8eb9
--- /dev/null
+++ b/t/t0028-working-tree-encoding.sh
@@ -0,0 +1,245 @@
+#!/bin/sh
+
+test_description='working-tree-encoding conversion via gitattributes'
+
+. ./test-lib.sh
+
+GIT_TRACE_WORKING_TREE_ENCODING=1 && export GIT_TRACE_WORKING_TREE_ENCODING
+
+test_expect_success 'setup test files' '
+	git config core.eol lf &&
+
+	text="hallo there!\ncan you read me?" &&
+	echo "*.utf16 text working-tree-encoding=utf-16" >.gitattributes &&
+	printf "$text" >test.utf8.raw &&
+	printf "$text" | iconv -f UTF-8 -t UTF-16 >test.utf16.raw &&
+	printf "$text" | iconv -f UTF-8 -t UTF-32 >test.utf32.raw &&
+
+	# Line ending tests
+	printf "one\ntwo\nthree\n" >lf.utf8.raw &&
+	printf "one\r\ntwo\r\nthree\r\n" >crlf.utf8.raw &&
+
+	# BOM tests
+	printf "\0a\0b\0c"                         >nobom.utf16be.raw &&
+	printf "a\0b\0c\0"                         >nobom.utf16le.raw &&
+	printf "\376\777\0a\0b\0c"                 >bebom.utf16be.raw &&
+	printf "\777\376a\0b\0c\0"                 >lebom.utf16le.raw &&
+	printf "\0\0\0a\0\0\0b\0\0\0c"             >nobom.utf32be.raw &&
+	printf "a\0\0\0b\0\0\0c\0\0\0"             >nobom.utf32le.raw &&
+	printf "\0\0\376\777\0\0\0a\0\0\0b\0\0\0c" >bebom.utf32be.raw &&
+	printf "\777\376\0\0a\0\0\0b\0\0\0c\0\0\0" >lebom.utf32le.raw &&
+
+	# Add only UTF-16 file, we will add the UTF-32 file later
+	cp test.utf16.raw test.utf16 &&
+	cp test.utf32.raw test.utf32 &&
+	git add .gitattributes test.utf16 &&
+	git commit -m initial
+'
+
+test_expect_success 'ensure UTF-8 is stored in Git' '
+	test_when_finished "rm -f test.utf16.git" &&
+
+	git cat-file -p :test.utf16 >test.utf16.git &&
+	test_cmp_bin test.utf8.raw test.utf16.git
+'
+
+test_expect_success 're-encode to UTF-16 on checkout' '
+	test_when_finished "rm -f test.utf16.raw" &&
+
+	rm test.utf16 &&
+	git checkout test.utf16 &&
+	test_cmp_bin test.utf16.raw test.utf16
+'
+
+test_expect_success 'check $GIT_DIR/info/attributes support' '
+	test_when_finished "rm -f test.utf32.git" &&
+	test_when_finished "git reset --hard HEAD" &&
+
+	echo "*.utf32 text working-tree-encoding=utf-32" >.git/info/attributes &&
+	git add test.utf32 &&
+
+	git cat-file -p :test.utf32 >test.utf32.git &&
+	test_cmp_bin test.utf8.raw test.utf32.git
+'
+
+for i in 16 32
+do
+	test_expect_success "check prohibited UTF-${i} BOM" '
+		test_when_finished "git reset --hard HEAD" &&
+
+		echo "*.utf${i}be text working-tree-encoding=utf-${i}be" >>.gitattributes &&
+		echo "*.utf${i}le text working-tree-encoding=utf-${i}LE" >>.gitattributes &&
+
+		# Here we add a UTF-16 (resp. UTF-32) files with BOM (big/little-endian)
+		# but we tell Git to treat it as UTF-16BE/UTF-16LE (resp. UTF-32).
+		# In these cases the BOM is prohibited.
+		cp bebom.utf${i}be.raw bebom.utf${i}be &&
+		test_must_fail git add bebom.utf${i}be 2>err.out &&
+		test_i18ngrep "fatal: BOM is prohibited .* utf-${i}be" err.out &&
+		test_i18ngrep "use UTF-${i} as working-tree-encoding" err.out &&
+
+		cp lebom.utf${i}le.raw lebom.utf${i}be &&
+		test_must_fail git add lebom.utf${i}be 2>err.out &&
+		test_i18ngrep "fatal: BOM is prohibited .* utf-${i}be" err.out &&
+		test_i18ngrep "use UTF-${i} as working-tree-encoding" err.out &&
+
+		cp bebom.utf${i}be.raw bebom.utf${i}le &&
+		test_must_fail git add bebom.utf${i}le 2>err.out &&
+		test_i18ngrep "fatal: BOM is prohibited .* utf-${i}LE" err.out &&
+		test_i18ngrep "use UTF-${i} as working-tree-encoding" err.out &&
+
+		cp lebom.utf${i}le.raw lebom.utf${i}le &&
+		test_must_fail git add lebom.utf${i}le 2>err.out &&
+		test_i18ngrep "fatal: BOM is prohibited .* utf-${i}LE" err.out &&
+		test_i18ngrep "use UTF-${i} as working-tree-encoding" err.out
+	'
+
+	test_expect_success "check required UTF-${i} BOM" '
+		test_when_finished "git reset --hard HEAD" &&
+
+		echo "*.utf${i} text working-tree-encoding=utf-${i}" >>.gitattributes &&
+
+		cp nobom.utf${i}be.raw nobom.utf${i} &&
+		test_must_fail git add nobom.utf${i} 2>err.out &&
+		test_i18ngrep "fatal: BOM is required .* utf-${i}" err.out &&
+		test_i18ngrep "use UTF-${i}BE or UTF-${i}LE" err.out &&
+
+		cp nobom.utf${i}le.raw nobom.utf${i} &&
+		test_must_fail git add nobom.utf${i} 2>err.out &&
+		test_i18ngrep "fatal: BOM is required .* utf-${i}" err.out &&
+		test_i18ngrep "use UTF-${i}BE or UTF-${i}LE" err.out
+	'
+
+	test_expect_success "eol conversion for UTF-${i} encoded files on checkout" '
+		test_when_finished "rm -f crlf.utf${i}.raw lf.utf${i}.raw" &&
+		test_when_finished "git reset --hard HEAD^" &&
+
+		cat lf.utf8.raw | iconv -f UTF-8 -t UTF-${i} >lf.utf${i}.raw &&
+		cat crlf.utf8.raw | iconv -f UTF-8 -t UTF-${i} >crlf.utf${i}.raw &&
+		cp crlf.utf${i}.raw eol.utf${i} &&
+
+		cat >expectIndexLF <<-EOF &&
+			i/lf    w/-text attr/text             	eol.utf${i}
+		EOF
+
+		git add eol.utf${i} &&
+		git commit -m eol &&
+
+		# UTF-${i} with CRLF (Windows line endings)
+		rm eol.utf${i} &&
+		git -c core.eol=crlf checkout eol.utf${i} &&
+		test_cmp_bin crlf.utf${i}.raw eol.utf${i} &&
+
+		# Although the file has CRLF in the working tree,
+		# ensure LF in the index
+		git ls-files --eol eol.utf${i} >actual &&
+		test_cmp expectIndexLF actual &&
+
+		# UTF-${i} with LF (Unix line endings)
+		rm eol.utf${i} &&
+		git -c core.eol=lf checkout eol.utf${i} &&
+		test_cmp_bin lf.utf${i}.raw eol.utf${i} &&
+
+		# The file LF in the working tree, ensure LF in the index
+		git ls-files --eol eol.utf${i} >actual &&
+		test_cmp expectIndexLF actual
+	'
+done
+
+test_expect_success 'check unsupported encodings' '
+	test_when_finished "git reset --hard HEAD" &&
+
+	echo "*.set text working-tree-encoding" >.gitattributes &&
+	printf "set" >t.set &&
+	test_must_fail git add t.set 2>err.out &&
+	test_i18ngrep "true/false are no valid working-tree-encodings" err.out &&
+
+	echo "*.unset text -working-tree-encoding" >.gitattributes &&
+	printf "unset" >t.unset &&
+	git add t.unset &&
+
+	echo "*.empty text working-tree-encoding=" >.gitattributes &&
+	printf "empty" >t.empty &&
+	git add t.empty &&
+
+	echo "*.garbage text working-tree-encoding=garbage" >.gitattributes &&
+	printf "garbage" >t.garbage &&
+	test_must_fail git add t.garbage 2>err.out &&
+	test_i18ngrep "failed to encode" err.out
+'
+
+test_expect_success 'error if encoding round trip is not the same during refresh' '
+	BEFORE_STATE=$(git rev-parse HEAD) &&
+	test_when_finished "git reset --hard $BEFORE_STATE" &&
+
+	# Add and commit a UTF-16 file but skip the "working-tree-encoding"
+	# filter. Consequently, the in-repo representation is UTF-16 and not
+	# UTF-8. This simulates a Git version that has no working tree encoding
+	# support.
+	echo "*.utf16le text working-tree-encoding=utf-16le" >.gitattributes &&
+	echo "hallo" >nonsense.utf16le &&
+	TEST_HASH=$(git hash-object --no-filters -w nonsense.utf16le) &&
+	git update-index --add --cacheinfo 100644 $TEST_HASH nonsense.utf16le &&
+	COMMIT=$(git commit-tree -p $(git rev-parse HEAD) -m "plain commit" $(git write-tree)) &&
+	git update-ref refs/heads/master $COMMIT &&
+
+	test_must_fail git checkout HEAD^ 2>err.out &&
+	test_i18ngrep "error: .* overwritten by checkout:" err.out
+'
+
+test_expect_success 'error if encoding garbage is already in Git' '
+	BEFORE_STATE=$(git rev-parse HEAD) &&
+	test_when_finished "git reset --hard $BEFORE_STATE" &&
+
+	# Skip the UTF-16 filter for the added file
+	# This simulates a Git version that has no checkoutEncoding support
+	cp nobom.utf16be.raw nonsense.utf16 &&
+	TEST_HASH=$(git hash-object --no-filters -w nonsense.utf16) &&
+	git update-index --add --cacheinfo 100644 $TEST_HASH nonsense.utf16 &&
+	COMMIT=$(git commit-tree -p $(git rev-parse HEAD) -m "plain commit" $(git write-tree)) &&
+	git update-ref refs/heads/master $COMMIT &&
+
+	git diff 2>err.out &&
+	test_i18ngrep "error: BOM is required" err.out
+'
+
+test_expect_success 'check roundtrip encoding' '
+	test_when_finished "rm -f roundtrip.shift roundtrip.utf16" &&
+	test_when_finished "git reset --hard HEAD" &&
+
+	text="hallo there!\nroundtrip test here!" &&
+	printf "$text" | iconv -f UTF-8 -t SHIFT-JIS >roundtrip.shift &&
+	printf "$text" | iconv -f UTF-8 -t UTF-16 >roundtrip.utf16 &&
+	echo "*.shift text working-tree-encoding=SHIFT-JIS" >>.gitattributes &&
+
+	# SHIFT-JIS encoded files are round-trip checked by default...
+	GIT_TRACE=1 git add .gitattributes roundtrip.shift 2>&1 |
+		grep "Checking roundtrip encoding for SHIFT-JIS" &&
+	git reset &&
+
+	# ... unless we overwrite the Git config!
+	! GIT_TRACE=1 git -c core.checkRoundtripEncoding=garbage \
+		add .gitattributes roundtrip.shift 2>&1 |
+		grep "Checking roundtrip encoding for SHIFT-JIS" &&
+	git reset &&
+
+	# UTF-16 encoded files should not be round-trip checked by default...
+	! GIT_TRACE=1 git add roundtrip.utf16 2>&1 |
+		grep "Checking roundtrip encoding for UTF-16" &&
+	git reset &&
+
+	# ... unless we tell Git to check it!
+	GIT_TRACE=1 git -c core.checkRoundtripEncoding="UTF-16, UTF-32" \
+		add roundtrip.utf16 2>&1 |
+		grep "Checking roundtrip encoding for utf-16" &&
+	git reset &&
+
+	# ... unless we tell Git to check it!
+	# (here we also check that the casing of the encoding is irrelevant)
+	GIT_TRACE=1 git -c core.checkRoundtripEncoding="UTF-32, utf-16" \
+		add roundtrip.utf16 2>&1 |
+		grep "Checking roundtrip encoding for utf-16" &&
+	git reset
+'
+
+test_done
diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
index f46e3c4..21a8b53 100755
--- a/t/t0060-path-utils.sh
+++ b/t/t0060-path-utils.sh
@@ -349,4 +349,90 @@
 test_submodule_relative_url "(null)" "user@host:path/to/repo" "../subrepo" "user@host:path/to/subrepo"
 test_submodule_relative_url "(null)" "user@host:repo" "../subrepo" "user@host:subrepo"
 
+test_expect_success 'match .gitmodules' '
+	test-tool path-utils is_dotgitmodules \
+		.gitmodules \
+		\
+		.git${u200c}modules \
+		\
+		.Gitmodules \
+		.gitmoduleS \
+		\
+		".gitmodules " \
+		".gitmodules." \
+		".gitmodules  " \
+		".gitmodules. " \
+		".gitmodules ." \
+		".gitmodules.." \
+		".gitmodules   " \
+		".gitmodules.  " \
+		".gitmodules . " \
+		".gitmodules  ." \
+		\
+		".Gitmodules " \
+		".Gitmodules." \
+		".Gitmodules  " \
+		".Gitmodules. " \
+		".Gitmodules ." \
+		".Gitmodules.." \
+		".Gitmodules   " \
+		".Gitmodules.  " \
+		".Gitmodules . " \
+		".Gitmodules  ." \
+		\
+		GITMOD~1 \
+		gitmod~1 \
+		GITMOD~2 \
+		gitmod~3 \
+		GITMOD~4 \
+		\
+		"GITMOD~1 " \
+		"gitmod~2." \
+		"GITMOD~3  " \
+		"gitmod~4. " \
+		"GITMOD~1 ." \
+		"gitmod~2   " \
+		"GITMOD~3.  " \
+		"gitmod~4 . " \
+		\
+		GI7EBA~1 \
+		gi7eba~9 \
+		\
+		GI7EB~10 \
+		GI7EB~11 \
+		GI7EB~99 \
+		GI7EB~10 \
+		GI7E~100 \
+		GI7E~101 \
+		GI7E~999 \
+		~1000000 \
+		~9999999 \
+		\
+		--not \
+		".gitmodules x"  \
+		".gitmodules .x" \
+		\
+		" .gitmodules" \
+		\
+		..gitmodules \
+		\
+		gitmodules \
+		\
+		.gitmodule \
+		\
+		".gitmodules x " \
+		".gitmodules .x" \
+		\
+		GI7EBA~ \
+		GI7EBA~0 \
+		GI7EBA~~1 \
+		GI7EBA~X \
+		Gx7EBA~1 \
+		GI7EBX~1 \
+		\
+		GI7EB~1 \
+		GI7EB~01 \
+		GI7EB~1X
+'
+
 test_done
diff --git a/t/t0061-run-command.sh b/t/t0061-run-command.sh
index d03149b..c887ed5 100755
--- a/t/t0061-run-command.sh
+++ b/t/t0061-run-command.sh
@@ -145,7 +145,7 @@
 	expect="$1"
 	shift
 	GIT_TRACE=1 test-tool run-command "$@" run-command true 2>&1 >/dev/null | \
-		sed 's/.* run_command: //' >actual &&
+		sed -e 's/.* run_command: //' -e '/trace: .*/d' >actual &&
 	echo "$expect true" >expect &&
 	test_cmp expect actual
 }
diff --git a/t/t0090-cache-tree.sh b/t/t0090-cache-tree.sh
index 4ae0995..0c61268 100755
--- a/t/t0090-cache-tree.sh
+++ b/t/t0090-cache-tree.sh
@@ -9,7 +9,7 @@
 
 cmp_cache_tree () {
 	test-tool dump-cache-tree | sed -e '/#(ref)/d' >actual &&
-	sed "s/$_x40/SHA/" <actual >filtered &&
+	sed "s/$OID_REGEX/SHA/" <actual >filtered &&
 	test_cmp "$1" filtered
 }
 
diff --git a/t/t1000-read-tree-m-3way.sh b/t/t1000-read-tree-m-3way.sh
index 3c4d2d6..013c5a7 100755
--- a/t/t1000-read-tree-m-3way.sh
+++ b/t/t1000-read-tree-m-3way.sh
@@ -128,7 +128,7 @@
 EOF
 
 check_result () {
-	git ls-files --stage | sed -e 's/ '"$_x40"' / X /' >current &&
+	git ls-files --stage | sed -e 's/ '"$OID_REGEX"' / X /' >current &&
 	test_cmp expected current
 }
 
diff --git a/t/t1001-read-tree-m-2way.sh b/t/t1001-read-tree-m-2way.sh
index 5ededd8..1057a96 100755
--- a/t/t1001-read-tree-m-2way.sh
+++ b/t/t1001-read-tree-m-2way.sh
@@ -30,7 +30,7 @@
 compare_change () {
 	sed -n >current \
 	    -e '/^--- /d; /^+++ /d; /^@@ /d;' \
-	    -e 's/^\([-+][0-7][0-7][0-7][0-7][0-7][0-7]\) '"$_x40"' /\1 X /p' \
+	    -e 's/^\([-+][0-7][0-7][0-7][0-7][0-7][0-7]\) '"$OID_REGEX"' /\1 X /p' \
 	    "$1"
 	test_cmp expected current
 }
diff --git a/t/t1002-read-tree-m-u-2way.sh b/t/t1002-read-tree-m-u-2way.sh
index 7ca2e65..9c05f5e 100755
--- a/t/t1002-read-tree-m-u-2way.sh
+++ b/t/t1002-read-tree-m-u-2way.sh
@@ -16,7 +16,7 @@
 	    -e '1{/^diff --git /d;}' \
 	    -e '2{/^index /d;}' \
 	    -e '/^--- /d; /^+++ /d; /^@@ /d;' \
-	    -e 's/^\(.[0-7][0-7][0-7][0-7][0-7][0-7]\) '"$_x40"' /\1 X /' "$1"
+	    -e 's/^\(.[0-7][0-7][0-7][0-7][0-7][0-7]\) '"$OID_REGEX"' /\1 X /' "$1"
 	test_cmp expected current
 }
 
diff --git a/t/t1006-cat-file.sh b/t/t1006-cat-file.sh
index 2ac3b94..13dd510 100755
--- a/t/t1006-cat-file.sh
+++ b/t/t1006-cat-file.sh
@@ -236,8 +236,8 @@
 '
 
 test_expect_success 'empty --batch-check notices missing object' '
-	echo "$_z40 missing" >expect &&
-	echo "$_z40" | git cat-file --batch-check="" >actual &&
+	echo "$ZERO_OID missing" >expect &&
+	echo "$ZERO_OID" | git cat-file --batch-check="" >actual &&
 	test_cmp expect actual
 '
 
@@ -294,8 +294,8 @@
 
 test_expect_success 'confirm that neither loose blob is a delta' '
 	cat >expect <<-EOF &&
-	$_z40
-	$_z40
+	$ZERO_OID
+	$ZERO_OID
 	EOF
 	git cat-file --batch-check="%(deltabase)" <blobs >actual &&
 	test_cmp expect actual
diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh
index 532682f..a377530 100755
--- a/t/t1007-hash-object.sh
+++ b/t/t1007-hash-object.sh
@@ -9,13 +9,13 @@
 }
 
 test_blob_does_not_exist() {
-	test_expect_success 'blob does not exist in database' "
+	test_expect_success SHA1 'blob does not exist in database' "
 		test_must_fail git cat-file blob $1
 	"
 }
 
 test_blob_exists() {
-	test_expect_success 'blob exists in database' "
+	test_expect_success SHA1 'blob exists in database' "
 		git cat-file blob $1
 	"
 }
@@ -73,19 +73,19 @@
 
 push_repo
 
-test_expect_success 'hash a file' '
+test_expect_success SHA1 'hash a file' '
 	test $hello_sha1 = $(git hash-object hello)
 '
 
 test_blob_does_not_exist $hello_sha1
 
-test_expect_success 'hash from stdin' '
+test_expect_success SHA1 'hash from stdin' '
 	test $example_sha1 = $(git hash-object --stdin < example)
 '
 
 test_blob_does_not_exist $example_sha1
 
-test_expect_success 'hash a file and write to database' '
+test_expect_success SHA1 'hash a file and write to database' '
 	test $hello_sha1 = $(git hash-object -w hello)
 '
 
@@ -161,7 +161,7 @@
 for args in "-w --stdin" "--stdin -w"; do
 	push_repo
 
-	test_expect_success "hash from stdin and write to database ($args)" '
+	test_expect_success SHA1 "hash from stdin and write to database ($args)" '
 		test $example_sha1 = $(git hash-object $args < example)
 	'
 
@@ -176,14 +176,14 @@
 sha1s="$hello_sha1
 $example_sha1"
 
-test_expect_success "hash two files with names on stdin" '
+test_expect_success SHA1 "hash two files with names on stdin" '
 	test "$sha1s" = "$(echo_without_newline "$filenames" | git hash-object --stdin-paths)"
 '
 
 for args in "-w --stdin-paths" "--stdin-paths -w"; do
 	push_repo
 
-	test_expect_success "hash two files with names on stdin and write to database ($args)" '
+	test_expect_success SHA1 "hash two files with names on stdin and write to database ($args)" '
 		test "$sha1s" = "$(echo_without_newline "$filenames" | git hash-object $args)"
 	'
 
diff --git a/t/t1012-read-tree-df.sh b/t/t1012-read-tree-df.sh
index a6a04b6..57f0770 100755
--- a/t/t1012-read-tree-df.sh
+++ b/t/t1012-read-tree-df.sh
@@ -32,7 +32,7 @@
 
 checkindex () {
 	git ls-files -s |
-	sed "s|^[0-7][0-7]* $_x40 \([0-3]\)	|\1 |" >current &&
+	sed "s|^[0-7][0-7]* $OID_REGEX \([0-3]\)	|\1 |" >current &&
 	cat >expect &&
 	test_cmp expect current
 }
diff --git a/t/t1300-repo-config.sh b/t/t1300-config.sh
similarity index 89%
rename from t/t1300-repo-config.sh
rename to t/t1300-config.sh
index e95b1e6..03c2237 100755
--- a/t/t1300-repo-config.sh
+++ b/t/t1300-config.sh
@@ -108,6 +108,7 @@
 [beta]
 baz = multiple \
 lines
+foo = bar
 EOF
 
 test_expect_success 'unset with cont. lines' '
@@ -118,6 +119,7 @@
 [alpha]
 bar = foo
 [beta]
+foo = bar
 EOF
 
 test_expect_success 'unset with cont. lines is correct' 'test_cmp expect .git/config'
@@ -740,7 +742,7 @@
 	do
 	    git config --bool --get bool.true$i >>result
 	    git config --bool --get bool.false$i >>result
-        done &&
+	done &&
 	test_cmp expect result'
 
 test_expect_success 'invalid bool (--get)' '
@@ -931,6 +933,36 @@
 	test_must_fail git config --expiry-date date.invalid1
 '
 
+test_expect_success 'get --type=color' '
+	rm .git/config &&
+	git config foo.color "red" &&
+	git config --get --type=color foo.color >actual.raw &&
+	test_decode_color <actual.raw >actual &&
+	echo "<RED>" >expect &&
+	test_cmp expect actual
+'
+
+cat >expect << EOF
+[foo]
+	color = red
+EOF
+
+test_expect_success 'set --type=color' '
+	rm .git/config &&
+	git config --type=color foo.color "red" &&
+	test_cmp expect .git/config
+'
+
+test_expect_success 'get --type=color barfs on non-color' '
+	echo "[foo]bar=not-a-color" >.git/config &&
+	test_must_fail git config --get --type=color foo.bar
+'
+
+test_expect_success 'set --type=color barfs on non-color' '
+	test_must_fail git config --type=color foo.color "not-a-color" 2>error &&
+	test_i18ngrep "cannot parse color" error
+'
+
 cat > expect << EOF
 [quote]
 	leading = " test"
@@ -1411,7 +1443,7 @@
 '
 
 # good section hygiene
-test_expect_failure 'unsetting the last key in a section removes header' '
+test_expect_success '--unset last key removes section (except if commented)' '
 	cat >.git/config <<-\EOF &&
 	# some generic comment on the configuration file itself
 	# a comment specific to this "section" section.
@@ -1425,13 +1457,86 @@
 
 	cat >expect <<-\EOF &&
 	# some generic comment on the configuration file itself
+	# a comment specific to this "section" section.
+	[section]
+	# some intervening lines
+	# that should also be dropped
+
+	# please be careful when you update the above variable
 	EOF
 
 	git config --unset section.key &&
-	test_cmp expect .git/config
+	test_cmp expect .git/config &&
+
+	cat >.git/config <<-\EOF &&
+	[section]
+	key = value
+	[next-section]
+	EOF
+
+	cat >expect <<-\EOF &&
+	[next-section]
+	EOF
+
+	git config --unset section.key &&
+	test_cmp expect .git/config &&
+
+	q_to_tab >.git/config <<-\EOF &&
+	[one]
+	Qkey = "multiline \
+	QQ# with comment"
+	[two]
+	key = true
+	EOF
+	git config --unset two.key &&
+	! grep two .git/config &&
+
+	q_to_tab >.git/config <<-\EOF &&
+	[one]
+	Qkey = "multiline \
+	QQ# with comment"
+	[one]
+	key = true
+	EOF
+	git config --unset-all one.key &&
+	test_line_count = 0 .git/config &&
+
+	q_to_tab >.git/config <<-\EOF &&
+	[one]
+	Qkey = true
+	Q# a comment not at the start
+	[two]
+	Qkey = true
+	EOF
+	git config --unset two.key &&
+	grep two .git/config &&
+
+	q_to_tab >.git/config <<-\EOF &&
+	[one]
+	Qkey = not [two "subsection"]
+	[two "subsection"]
+	[two "subsection"]
+	Qkey = true
+	[TWO "subsection"]
+	[one]
+	EOF
+	git config --unset two.subsection.key &&
+	test "not [two subsection]" = "$(git config one.key)" &&
+	test_line_count = 3 .git/config
 '
 
-test_expect_failure 'adding a key into an empty section reuses header' '
+test_expect_success '--unset-all removes section if empty & uncommented' '
+	cat >.git/config <<-\EOF &&
+	[section]
+	key = value1
+	key = value2
+	EOF
+
+	git config --unset-all section.key &&
+	test_line_count = 0 .git/config
+'
+
+test_expect_success 'adding a key into an empty section reuses header' '
 	cat >.git/config <<-\EOF &&
 	[section]
 	EOF
@@ -1611,4 +1716,88 @@
 	test_expect_code 128 nongit git config --local foo.bar
 '
 
+cat >.git/config <<-\EOF &&
+[core]
+foo = true
+number = 10
+big = 1M
+EOF
+
+test_expect_success 'identical modern --type specifiers are allowed' '
+	git config --type=int --type=int core.big >actual &&
+	echo 1048576 >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'identical legacy --type specifiers are allowed' '
+	git config --int --int core.big >actual &&
+	echo 1048576 >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'identical mixed --type specifiers are allowed' '
+	git config --int --type=int core.big >actual &&
+	echo 1048576 >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'non-identical modern --type specifiers are not allowed' '
+	test_must_fail git config --type=int --type=bool core.big 2>error &&
+	test_i18ngrep "only one type at a time" error
+'
+
+test_expect_success 'non-identical legacy --type specifiers are not allowed' '
+	test_must_fail git config --int --bool core.big 2>error &&
+	test_i18ngrep "only one type at a time" error
+'
+
+test_expect_success 'non-identical mixed --type specifiers are not allowed' '
+	test_must_fail git config --type=int --bool core.big 2>error &&
+	test_i18ngrep "only one type at a time" error
+'
+
+test_expect_success '--type allows valid type specifiers' '
+	echo "true" >expect &&
+	git config --type=bool core.foo >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--no-type unsets type specifiers' '
+	echo "10" >expect &&
+	git config --type=bool --no-type core.number >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'unset type specifiers may be reset to conflicting ones' '
+	echo 1048576 >expect &&
+	git config --type=bool --no-type --type=int core.big >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--type rejects unknown specifiers' '
+	test_must_fail git config --type=nonsense core.foo 2>error &&
+	test_i18ngrep "unrecognized --type argument" error
+'
+
+test_expect_success '--replace-all does not invent newlines' '
+	q_to_tab >.git/config <<-\EOF &&
+	[abc]key
+	QkeepSection
+	[xyz]
+	Qkey = 1
+	[abc]
+	Qkey = a
+	EOF
+	q_to_tab >expect <<-\EOF &&
+	[abc]
+	QkeepSection
+	[xyz]
+	Qkey = 1
+	[abc]
+	Qkey = b
+	EOF
+	git config --replace-all abc.key b &&
+	test_cmp .git/config expect
+'
+
 test_done
diff --git a/t/t1307-config-blob.sh b/t/t1307-config-blob.sh
index eed31ff..37dc689 100755
--- a/t/t1307-config-blob.sh
+++ b/t/t1307-config-blob.sh
@@ -73,4 +73,8 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'config --blob outside of a repository is an error' '
+	test_must_fail nongit git config --blob=foo --list
+'
+
 test_done
diff --git a/t/t1310-config-default.sh b/t/t1310-config-default.sh
new file mode 100755
index 0000000..6049d91
--- /dev/null
+++ b/t/t1310-config-default.sh
@@ -0,0 +1,36 @@
+#!/bin/sh
+
+test_description='Test git config in different settings (with --default)'
+
+. ./test-lib.sh
+
+test_expect_success 'uses --default when entry missing' '
+	echo quux >expect &&
+	git config -f config --default=quux core.foo >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'does not use --default when entry present' '
+	echo bar >expect &&
+	git -c core.foo=bar config --default=baz core.foo >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'canonicalizes --default with appropriate type' '
+	echo true >expect &&
+	git config -f config --default=yes --bool core.foo >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'dies when --default cannot be parsed' '
+	test_must_fail git config -f config --type=expiry-date --default=x --get \
+		not.a.section 2>error &&
+	test_i18ngrep "failed to format default config value" error
+'
+
+test_expect_success 'does not allow --default without --get' '
+	test_must_fail git config --default=quux --unset a.section >output 2>&1 &&
+	test_i18ngrep "\-\-default is only applicable to" output
+'
+
+test_done
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index 664a3a4..e1fd0f0 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -6,7 +6,7 @@
 test_description='Test git update-ref and basic ref logging'
 . ./test-lib.sh
 
-Z=$_z40
+Z=$ZERO_OID
 
 m=refs/heads/master
 n_dir=refs/heads/gu
@@ -457,6 +457,66 @@
 	test OTHER = $(git cat-file blob "master@{2005-05-26 23:42}:F")
 '
 
+# Test adding and deleting pseudorefs
+
+test_expect_success 'given old value for missing pseudoref, do not create' '
+	test_must_fail git update-ref PSEUDOREF $A $B 2>err &&
+	test_path_is_missing .git/PSEUDOREF &&
+	grep "could not read ref" err
+'
+
+test_expect_success 'create pseudoref' '
+	git update-ref PSEUDOREF $A &&
+	test $A = $(cat .git/PSEUDOREF)
+'
+
+test_expect_success 'overwrite pseudoref with no old value given' '
+	git update-ref PSEUDOREF $B &&
+	test $B = $(cat .git/PSEUDOREF)
+'
+
+test_expect_success 'overwrite pseudoref with correct old value' '
+	git update-ref PSEUDOREF $C $B &&
+	test $C = $(cat .git/PSEUDOREF)
+'
+
+test_expect_success 'do not overwrite pseudoref with wrong old value' '
+	test_must_fail git update-ref PSEUDOREF $D $E 2>err &&
+	test $C = $(cat .git/PSEUDOREF) &&
+	grep "unexpected object ID" err
+'
+
+test_expect_success 'delete pseudoref' '
+	git update-ref -d PSEUDOREF &&
+	test_path_is_missing .git/PSEUDOREF
+'
+
+test_expect_success 'do not delete pseudoref with wrong old value' '
+	git update-ref PSEUDOREF $A &&
+	test_must_fail git update-ref -d PSEUDOREF $B 2>err &&
+	test $A = $(cat .git/PSEUDOREF) &&
+	grep "unexpected object ID" err
+'
+
+test_expect_success 'delete pseudoref with correct old value' '
+	git update-ref -d PSEUDOREF $A &&
+	test_path_is_missing .git/PSEUDOREF
+'
+
+test_expect_success 'create pseudoref with old OID zero' '
+	git update-ref PSEUDOREF $A $Z &&
+	test $A = $(cat .git/PSEUDOREF)
+'
+
+test_expect_success 'do not overwrite pseudoref with old OID zero' '
+	test_when_finished git update-ref -d PSEUDOREF &&
+	test_must_fail git update-ref PSEUDOREF $B $Z 2>err &&
+	test $A = $(cat .git/PSEUDOREF) &&
+	grep "already exists" err
+'
+
+# Test --stdin
+
 a=refs/heads/a
 b=refs/heads/b
 c=refs/heads/c
diff --git a/t/t1401-symbolic-ref.sh b/t/t1401-symbolic-ref.sh
index 9e782a8..a4ebb0b 100755
--- a/t/t1401-symbolic-ref.sh
+++ b/t/t1401-symbolic-ref.sh
@@ -65,7 +65,7 @@
 test_expect_success 'symbolic-ref fails to delete real ref' '
 	echo "fatal: Cannot delete refs/heads/foo, not a symbolic ref" >expect &&
 	test_must_fail git symbolic-ref -d refs/heads/foo >actual 2>&1 &&
-	test_path_is_file .git/refs/heads/foo &&
+	git rev-parse --verify refs/heads/foo &&
 	test_cmp expect actual
 '
 reset_to_sane
diff --git a/t/t1407-worktree-ref-store.sh b/t/t1407-worktree-ref-store.sh
index 2211f98..4623ae1 100755
--- a/t/t1407-worktree-ref-store.sh
+++ b/t/t1407-worktree-ref-store.sh
@@ -50,13 +50,13 @@
 '
 
 test_expect_success 'for_each_reflog()' '
-	echo $_z40 > .git/logs/PSEUDO-MAIN &&
+	echo $ZERO_OID > .git/logs/PSEUDO-MAIN &&
 	mkdir -p     .git/logs/refs/bisect &&
-	echo $_z40 > .git/logs/refs/bisect/random &&
+	echo $ZERO_OID > .git/logs/refs/bisect/random &&
 
-	echo $_z40 > .git/worktrees/wt/logs/PSEUDO-WT &&
+	echo $ZERO_OID > .git/worktrees/wt/logs/PSEUDO-WT &&
 	mkdir -p     .git/worktrees/wt/logs/refs/bisect &&
-	echo $_z40 > .git/worktrees/wt/logs/refs/bisect/wt-random &&
+	echo $ZERO_OID > .git/worktrees/wt/logs/refs/bisect/wt-random &&
 
 	$RWT for-each-reflog | cut -c 42- | sort >actual &&
 	cat >expected <<-\EOF &&
diff --git a/t/t1450-fsck.sh b/t/t1450-fsck.sh
index cb4b66e..91fd714 100755
--- a/t/t1450-fsck.sh
+++ b/t/t1450-fsck.sh
@@ -713,7 +713,7 @@
 
 test_expect_success 'fsck $name notices bogus $name' '
 	test_must_fail git fsck bogus &&
-	test_must_fail git fsck $_z40
+	test_must_fail git fsck $ZERO_OID
 '
 
 test_expect_success 'bogus head does not fallback to all heads' '
@@ -723,7 +723,7 @@
 	blob=$(git rev-parse :foo) &&
 	test_when_finished "git rm --cached foo" &&
 	remove_object $blob &&
-	test_must_fail git fsck $_z40 >out 2>&1 &&
+	test_must_fail git fsck $ZERO_OID >out 2>&1 &&
 	! grep $blob out
 '
 
diff --git a/t/t1501-work-tree.sh b/t/t1501-work-tree.sh
index 9c0bc65..afcdfaf 100755
--- a/t/t1501-work-tree.sh
+++ b/t/t1501-work-tree.sh
@@ -238,10 +238,10 @@
 
 test_expect_success 'diff-index respects work tree under .git dir' '
 	cat >diff-index-cached.expected <<-EOF &&
-	:000000 100644 $_z40 $EMPTY_BLOB A	sub/dir/tracked
+	:000000 100644 $ZERO_OID $EMPTY_BLOB A	sub/dir/tracked
 	EOF
 	cat >diff-index.expected <<-EOF &&
-	:000000 100644 $_z40 $_z40 A	sub/dir/tracked
+	:000000 100644 $ZERO_OID $ZERO_OID A	sub/dir/tracked
 	EOF
 
 	(
@@ -257,7 +257,7 @@
 
 test_expect_success 'diff-files respects work tree under .git dir' '
 	cat >diff-files.expected <<-EOF &&
-	:100644 100644 $EMPTY_BLOB $_z40 M	sub/dir/tracked
+	:100644 100644 $EMPTY_BLOB $ZERO_OID M	sub/dir/tracked
 	EOF
 
 	(
diff --git a/t/t1510-repo-setup.sh b/t/t1510-repo-setup.sh
index e6854b8..972bd9c 100755
--- a/t/t1510-repo-setup.sh
+++ b/t/t1510-repo-setup.sh
@@ -238,7 +238,6 @@
 '
 
 test_expect_success '#1: GIT_WORK_TREE without explicit GIT_DIR is accepted' '
-	mkdir -p wt &&
 	try_repo 1 "$here" unset unset "" unset \
 		"$here/1/.git" "$here" "$here" 1/ \
 		"$here/1/.git" "$here" "$here" 1/sub/ 2>message &&
diff --git a/t/t1512-rev-parse-disambiguation.sh b/t/t1512-rev-parse-disambiguation.sh
index 711704b..96fe375 100755
--- a/t/t1512-rev-parse-disambiguation.sh
+++ b/t/t1512-rev-parse-disambiguation.sh
@@ -22,6 +22,12 @@
 
 . ./test-lib.sh
 
+if ! test_have_prereq SHA1
+then
+	skip_all='not using SHA-1 for objects'
+	test_done
+fi
+
 test_expect_success 'blob and tree' '
 	test_tick &&
 	(
@@ -361,4 +367,25 @@
 		git -c core.disambiguate=committish rev-parse $sha1^{tree}
 '
 
+test_expect_success C_LOCALE_OUTPUT 'ambiguous commits are printed by type first, then hash order' '
+	test_must_fail git rev-parse 0000 2>stderr &&
+	grep ^hint: stderr >hints &&
+	grep 0000 hints >objects &&
+	cat >expected <<-\EOF &&
+	tag
+	commit
+	tree
+	blob
+	EOF
+	awk "{print \$3}" <objects >objects.types &&
+	uniq <objects.types >objects.types.uniq &&
+	test_cmp expected objects.types.uniq &&
+	for type in tag commit tree blob
+	do
+		grep $type objects >$type.objects &&
+		sort $type.objects >$type.objects.sorted &&
+		test_cmp $type.objects.sorted $type.objects
+	done
+'
+
 test_done
diff --git a/t/t1601-index-bogus.sh b/t/t1601-index-bogus.sh
index 73cc932..4171f1e 100755
--- a/t/t1601-index-bogus.sh
+++ b/t/t1601-index-bogus.sh
@@ -4,7 +4,7 @@
 . ./test-lib.sh
 
 test_expect_success 'create tree with null sha1' '
-	tree=$(printf "160000 commit $_z40\\tbroken\\n" | git mktree)
+	tree=$(printf "160000 commit $ZERO_OID\\tbroken\\n" | git mktree)
 '
 
 test_expect_success 'read-tree refuses to read null sha1' '
diff --git a/t/t1700-split-index.sh b/t/t1700-split-index.sh
index e4f4c4d..1e81b33 100755
--- a/t/t1700-split-index.sh
+++ b/t/t1700-split-index.sh
@@ -426,7 +426,7 @@
 	git commit -m "commit" &&
 	{
 		git ls-tree HEAD &&
-		printf "160000 commit $_z40\\tbroken\\n"
+		printf "160000 commit $ZERO_OID\\tbroken\\n"
 	} >broken-tree &&
 	echo "add broken entry" >msg &&
 
diff --git a/t/t2011-checkout-invalid-head.sh b/t/t2011-checkout-invalid-head.sh
index c5501b0..0e8d56a 100755
--- a/t/t2011-checkout-invalid-head.sh
+++ b/t/t2011-checkout-invalid-head.sh
@@ -15,7 +15,7 @@
 '
 
 test_expect_success 'checkout master from invalid HEAD' '
-	echo $_z40 >.git/HEAD &&
+	echo $ZERO_OID >.git/HEAD &&
 	git checkout master --
 '
 
diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index d0d2e4f..d2e49f7 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -198,13 +198,25 @@
 	test_cmp_rev HEAD bat
 '
 
-test_expect_success '"add" auto-vivify does not clobber existing branch' '
-	test_commit c1 &&
-	test_commit c2 &&
-	git branch precious HEAD~1 &&
-	test_must_fail git worktree add precious &&
-	test_cmp_rev HEAD~1 precious &&
-	test_path_is_missing precious
+test_expect_success '"add" checks out existing branch of dwimd name' '
+	git branch dwim HEAD~1 &&
+	git worktree add dwim &&
+	test_cmp_rev HEAD~1 dwim &&
+	(
+		cd dwim &&
+		test_cmp_rev HEAD dwim
+	)
+'
+
+test_expect_success '"add <path>" dwim fails with checked out branch' '
+	git checkout -b test-branch &&
+	test_must_fail git worktree add test-branch &&
+	test_path_is_missing test-branch
+'
+
+test_expect_success '"add --force" with existing dwimd name doesnt die' '
+	git checkout test-branch &&
+	git worktree add --force test-branch
 '
 
 test_expect_success '"add" no auto-vivify with --detach and <branch> omitted' '
@@ -465,7 +477,7 @@
 test_expect_success '"add" invokes post-checkout hook (branch)' '
 	post_checkout_hook &&
 	{
-		echo $_z40 $(git rev-parse HEAD) 1 &&
+		echo $ZERO_OID $(git rev-parse HEAD) 1 &&
 		echo $(pwd)/.git/worktrees/gumby &&
 		echo $(pwd)/gumby
 	} >hook.expect &&
@@ -476,7 +488,7 @@
 test_expect_success '"add" invokes post-checkout hook (detached)' '
 	post_checkout_hook &&
 	{
-		echo $_z40 $(git rev-parse HEAD) 1 &&
+		echo $ZERO_OID $(git rev-parse HEAD) 1 &&
 		echo $(pwd)/.git/worktrees/grumpy &&
 		echo $(pwd)/grumpy
 	} >hook.expect &&
@@ -494,7 +506,7 @@
 test_expect_success '"add" in other worktree invokes post-checkout hook' '
 	post_checkout_hook &&
 	{
-		echo $_z40 $(git rev-parse HEAD) 1 &&
+		echo $ZERO_OID $(git rev-parse HEAD) 1 &&
 		echo $(pwd)/.git/worktrees/guppy &&
 		echo $(pwd)/guppy
 	} >hook.expect &&
@@ -506,7 +518,7 @@
 	rm -rf bare &&
 	git clone --bare . bare &&
 	{
-		echo $_z40 $(git --git-dir=bare rev-parse HEAD) 1 &&
+		echo $ZERO_OID $(git --git-dir=bare rev-parse HEAD) 1 &&
 		echo $(pwd)/bare/worktrees/goozy &&
 		echo $(pwd)/goozy
 	} >hook.expect &&
diff --git a/t/t2027-worktree-list.sh b/t/t2027-worktree-list.sh
index 720063b..bb6fb9b 100755
--- a/t/t2027-worktree-list.sh
+++ b/t/t2027-worktree-list.sh
@@ -116,7 +116,7 @@
 		git worktree add linked &&
 		cat >expected <<-EOF &&
 		worktree $(pwd)
-		HEAD $_z40
+		HEAD $ZERO_OID
 
 		EOF
 		cd linked &&
diff --git a/t/t2107-update-index-basic.sh b/t/t2107-update-index-basic.sh
index 1db7e6a..2242cd0 100755
--- a/t/t2107-update-index-basic.sh
+++ b/t/t2107-update-index-basic.sh
@@ -37,7 +37,7 @@
 	echo content >file &&
 	git add file &&
 	git rev-parse :file >expect &&
-	test_must_fail git update-index --cacheinfo 100644 $_z40 file &&
+	test_must_fail git update-index --cacheinfo 100644 $ZERO_OID file &&
 	git rev-parse :file >actual &&
 	test_cmp expect actual
 '
@@ -47,7 +47,7 @@
 	(cd submodule && test_commit foo) &&
 	git add submodule &&
 	git rev-parse :submodule >expect &&
-	test_must_fail git update-index --cacheinfo 160000 $_z40 submodule &&
+	test_must_fail git update-index --cacheinfo 160000 $ZERO_OID submodule &&
 	git rev-parse :submodule >actual &&
 	test_cmp expect actual
 '
diff --git a/t/t2201-add-update-typechange.sh b/t/t2201-add-update-typechange.sh
index 954fc51..a4eec0a 100755
--- a/t/t2201-add-update-typechange.sh
+++ b/t/t2201-add-update-typechange.sh
@@ -75,35 +75,35 @@
 		git ls-tree -r HEAD |
 		sed -e "s/^/:/" -e "
 			/	caskly/{
-				s/	caskly/ $_z40 D&/
+				s/	caskly/ $ZERO_OID D&/
 				s/blob/000000/
 			}
 			/	nitfol/{
-				s/	nitfol/ $_z40 $T_letter&/
+				s/	nitfol/ $ZERO_OID $T_letter&/
 				s/blob/100644/
 			}
 			/	rezrov.bozbar/{
-				s/	rezrov.bozbar/ $_z40 D&/
+				s/	rezrov.bozbar/ $ZERO_OID D&/
 				s/blob/000000/
 			}
 			/	xyzzy/{
-				s/	xyzzy/ $_z40 D&/
+				s/	xyzzy/ $ZERO_OID D&/
 				s/blob/000000/
 			}
 			/	yomin/{
-			    s/	yomin/ $_z40 T&/
+			    s/	yomin/ $ZERO_OID T&/
 				s/blob/160000/
 			}
 		"
 	} >expect &&
 	{
 		cat expect
-		echo ":100644 160000 $_empty $_z40 T	yonk"
-		echo ":100644 000000 $_empty $_z40 D	zifmia"
+		echo ":100644 160000 $_empty $ZERO_OID T	yonk"
+		echo ":100644 000000 $_empty $ZERO_OID D	zifmia"
 	} >expect-files &&
 	{
 		cat expect
-		echo ":000000 160000 $_z40 $_z40 A	yonk"
+		echo ":000000 160000 $ZERO_OID $ZERO_OID A	yonk"
 	} >expect-index &&
 	{
 		echo "100644 $_empty 0	nitfol"
diff --git a/t/t2203-add-intent.sh b/t/t2203-add-intent.sh
index 78236dc..04d840a 100755
--- a/t/t2203-add-intent.sh
+++ b/t/t2203-add-intent.sh
@@ -27,12 +27,12 @@
 
 test_expect_success 'git status with porcelain v2' '
 	git status --porcelain=v2 | grep -v "^?" >actual &&
-	nam1=d00491fd7e5bb6fa28c517a0bb32b8b506539d4d &&
-	nam2=ce013625030ba8dba906f756967f9e9ca394464a &&
+	nam1=$(echo 1 | git hash-object --stdin) &&
+	nam2=$(git hash-object elif) &&
 	cat >expect <<-EOF &&
-	1 DA N... 100644 000000 100644 $nam1 $_z40 1.t
-	1 A. N... 000000 100644 100644 $_z40 $nam2 elif
-	1 .A N... 000000 000000 100644 $_z40 $_z40 file
+	1 DA N... 100644 000000 100644 $nam1 $ZERO_OID 1.t
+	1 A. N... 000000 100644 100644 $ZERO_OID $nam2 elif
+	1 .A N... 000000 000000 100644 $ZERO_OID $ZERO_OID file
 	EOF
 	test_cmp expect actual
 '
@@ -181,7 +181,7 @@
 		EOF
 		test_cmp expected.2 actual.2 &&
 
-		hash=12f00e90b6ef79117ce6e650416b8cf517099b78 &&
+		hash=$(git hash-object third) &&
 		git status --porcelain=v2 | grep -v "^?" >actual.3 &&
 		cat >expected.3 <<-EOF &&
 		2 .R N... 100644 100644 100644 $hash $hash R100 third	first
@@ -212,7 +212,7 @@
 		EOF
 		test_cmp expected.2 actual.2 &&
 
-		hash=12f00e90b6ef79117ce6e650416b8cf517099b78 &&
+		hash=$(git hash-object third) &&
 		git status --porcelain=v2 | grep -v "^?" >actual.3 &&
 		cat >expected.3 <<-EOF &&
 		2 R. N... 100644 100644 100644 $hash $hash R100 second	first
diff --git a/t/t3034-merge-recursive-rename-options.sh b/t/t3034-merge-recursive-rename-options.sh
index b9c4028..3d9fae6 100755
--- a/t/t3034-merge-recursive-rename-options.sh
+++ b/t/t3034-merge-recursive-rename-options.sh
@@ -309,4 +309,22 @@
 	check_threshold_0
 '
 
+test_expect_success 'merge.renames disables rename detection' '
+	git read-tree --reset -u HEAD &&
+	git -c merge.renames=false merge-recursive $tail &&
+	check_no_renames
+'
+
+test_expect_success 'merge.renames defaults to diff.renames' '
+	git read-tree --reset -u HEAD &&
+	git -c diff.renames=false merge-recursive $tail &&
+	check_no_renames
+'
+
+test_expect_success 'merge.renames overrides diff.renames' '
+	git read-tree --reset -u HEAD &&
+	test_must_fail git -c diff.renames=false -c merge.renames=true merge-recursive $tail &&
+	$check_50
+'
+
 test_done
diff --git a/t/t3100-ls-tree-restrict.sh b/t/t3100-ls-tree-restrict.sh
index 325114f..18baf49 100755
--- a/t/t3100-ls-tree-restrict.sh
+++ b/t/t3100-ls-tree-restrict.sh
@@ -32,7 +32,7 @@
      echo $tree'
 
 test_output () {
-    sed -e "s/ $_x40	/ X	/" <current >check
+    sed -e "s/ $OID_REGEX	/ X	/" <current >check
     test_cmp expected check
 }
 
diff --git a/t/t3101-ls-tree-dirname.sh b/t/t3101-ls-tree-dirname.sh
index 327ded4..12bf310 100755
--- a/t/t3101-ls-tree-dirname.sh
+++ b/t/t3101-ls-tree-dirname.sh
@@ -40,7 +40,7 @@
 '
 
 test_output () {
-	sed -e "s/ $_x40	/ X	/" <current >check &&
+	sed -e "s/ $OID_REGEX	/ X	/" <current >check &&
 	test_cmp expected check
 }
 
diff --git a/t/t3103-ls-tree-misc.sh b/t/t3103-ls-tree-misc.sh
index 09dcf04..1452091 100755
--- a/t/t3103-ls-tree-misc.sh
+++ b/t/t3103-ls-tree-misc.sh
@@ -17,7 +17,8 @@
 '
 
 test_expect_success 'ls-tree fails with non-zero exit code on broken tree' '
-	rm -f .git/objects/5f/cffbd6e4c5c5b8d81f5e9314b20e338e3ffff5 &&
+	tree=$(git rev-parse HEAD:a) &&
+	rm -f .git/objects/$(echo $tree | sed -e "s,^\(..\),\1/,") &&
 	test_must_fail git ls-tree -r HEAD
 '
 
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index c0ef946..69ea820 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -47,7 +47,7 @@
 '
 
 cat >expect <<EOF
-$_z40 $HEAD $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	branch: Created from master
+$ZERO_OID $HEAD $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	branch: Created from master
 EOF
 test_expect_success 'git branch -l d/e/f should create a branch and a log' '
 	GIT_COMMITTER_DATE="2005-05-26 23:30" \
@@ -234,34 +234,34 @@
 
 test_expect_success 'git branch -v -d t should work' '
 	git branch t &&
-	test_path_is_file .git/refs/heads/t &&
+	git rev-parse --verify refs/heads/t &&
 	git branch -v -d t &&
-	test_path_is_missing .git/refs/heads/t
+	test_must_fail git rev-parse --verify refs/heads/t
 '
 
 test_expect_success 'git branch -v -m t s should work' '
 	git branch t &&
-	test_path_is_file .git/refs/heads/t &&
+	git rev-parse --verify refs/heads/t &&
 	git branch -v -m t s &&
-	test_path_is_missing .git/refs/heads/t &&
-	test_path_is_file .git/refs/heads/s &&
+	test_must_fail git rev-parse --verify refs/heads/t &&
+	git rev-parse --verify refs/heads/s &&
 	git branch -d s
 '
 
 test_expect_success 'git branch -m -d t s should fail' '
 	git branch t &&
-	test_path_is_file .git/refs/heads/t &&
+	git rev-parse refs/heads/t &&
 	test_must_fail git branch -m -d t s &&
 	git branch -d t &&
-	test_path_is_missing .git/refs/heads/t
+	test_must_fail git rev-parse refs/heads/t
 '
 
 test_expect_success 'git branch --list -d t should fail' '
 	git branch t &&
-	test_path_is_file .git/refs/heads/t &&
+	git rev-parse refs/heads/t &&
 	test_must_fail git branch --list -d t &&
 	git branch -d t &&
-	test_path_is_missing .git/refs/heads/t
+	test_must_fail git rev-parse refs/heads/t
 '
 
 test_expect_success 'git branch --list -v with --abbrev' '
@@ -901,7 +901,7 @@
 
 # Keep this test last, as it changes the current branch
 cat >expect <<EOF
-$_z40 $HEAD $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	branch: Created from master
+$ZERO_OID $HEAD $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	branch: Created from master
 EOF
 test_expect_success 'git checkout -b g/h/i -l should create a branch and a log' '
 	GIT_COMMITTER_DATE="2005-05-26 23:30" \
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 59c7665..c65826d 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -1204,10 +1204,6 @@
 	test A = $(git cat-file commit HEAD^^ | sed -ne \$p)
 '
 
-cat >expect <<EOF
-Successfully rebased and updated refs/heads/missing-commit.
-EOF
-
 test_expect_success 'rebase -i respects rebase.missingCommitsCheck = ignore' '
 	test_config rebase.missingCommitsCheck ignore &&
 	rebase_setup_and_clean missing-commit &&
@@ -1215,7 +1211,9 @@
 	FAKE_LINES="1 2 3 4" \
 		git rebase -i --root 2>actual &&
 	test D = $(git cat-file commit HEAD | sed -ne \$p) &&
-	test_i18ncmp expect actual
+	test_i18ngrep \
+		"Successfully rebased and updated refs/heads/missing-commit" \
+		actual
 '
 
 cat >expect <<EOF
@@ -1227,15 +1225,24 @@
 Use 'git config rebase.missingCommitsCheck' to change the level of warnings.
 The possible behaviours are: ignore, warn, error.
 
+Rebasing (1/4)
+Rebasing (2/4)
+Rebasing (3/4)
+Rebasing (4/4)
 Successfully rebased and updated refs/heads/missing-commit.
 EOF
 
+cr_to_nl () {
+	tr '\015' '\012'
+}
+
 test_expect_success 'rebase -i respects rebase.missingCommitsCheck = warn' '
 	test_config rebase.missingCommitsCheck warn &&
 	rebase_setup_and_clean missing-commit &&
 	set_fake_editor &&
 	FAKE_LINES="1 2 3 4" \
-		git rebase -i --root 2>actual &&
+		git rebase -i --root 2>actual.2 &&
+	cr_to_nl <actual.2 >actual &&
 	test_i18ncmp expect actual &&
 	test D = $(git cat-file commit HEAD | sed -ne \$p)
 '
diff --git a/t/t3418-rebase-continue.sh b/t/t3418-rebase-continue.sh
index 9214d0b..03bf1b8 100755
--- a/t/t3418-rebase-continue.sh
+++ b/t/t3418-rebase-continue.sh
@@ -88,6 +88,55 @@
 	git rebase --continue
 '
 
+test_expect_success '--skip after failed fixup cleans commit message' '
+	test_when_finished "test_might_fail git rebase --abort" &&
+	git checkout -b with-conflicting-fixup &&
+	test_commit wants-fixup &&
+	test_commit "fixup! wants-fixup" wants-fixup.t 1 wants-fixup-1 &&
+	test_commit "fixup! wants-fixup" wants-fixup.t 2 wants-fixup-2 &&
+	test_commit "fixup! wants-fixup" wants-fixup.t 3 wants-fixup-3 &&
+	test_must_fail env FAKE_LINES="1 fixup 2 squash 4" \
+		git rebase -i HEAD~4 &&
+
+	: now there is a conflict, and comments in the commit message &&
+	git show HEAD >out &&
+	grep "fixup! wants-fixup" out &&
+
+	: skip and continue &&
+	echo "cp \"\$1\" .git/copy.txt" | write_script copy-editor.sh &&
+	(test_set_editor "$PWD/copy-editor.sh" && git rebase --skip) &&
+
+	: the user should not have had to edit the commit message &&
+	test_path_is_missing .git/copy.txt &&
+
+	: now the comments in the commit message should have been cleaned up &&
+	git show HEAD >out &&
+	! grep "fixup! wants-fixup" out &&
+
+	: now, let us ensure that "squash" is handled correctly &&
+	git reset --hard wants-fixup-3 &&
+	test_must_fail env FAKE_LINES="1 squash 4 squash 2 squash 4" \
+		git rebase -i HEAD~4 &&
+
+	: the first squash failed, but there are two more in the chain &&
+	(test_set_editor "$PWD/copy-editor.sh" &&
+	 test_must_fail git rebase --skip) &&
+
+	: not the final squash, no need to edit the commit message &&
+	test_path_is_missing .git/copy.txt &&
+
+	: The first squash was skipped, therefore: &&
+	git show HEAD >out &&
+	test_i18ngrep "# This is a combination of 2 commits" out &&
+
+	(test_set_editor "$PWD/copy-editor.sh" && git rebase --skip) &&
+	git show HEAD >out &&
+	test_i18ngrep ! "# This is a combination" out &&
+
+	: Final squash failed, but there was still a squash &&
+	test_i18ngrep "# This is a combination of 2 commits" .git/copy.txt
+'
+
 test_expect_success 'setup rerere database' '
 	rm -fr .git/rebase-* &&
 	git reset --hard commit-new-file-F3-on-topic-branch &&
diff --git a/t/t3421-rebase-topology-linear.sh b/t/t3421-rebase-topology-linear.sh
index e7438ad..99b2aac 100755
--- a/t/t3421-rebase-topology-linear.sh
+++ b/t/t3421-rebase-topology-linear.sh
@@ -328,9 +328,9 @@
 		test_cmp_rev c HEAD
 	"
 }
-test_run_rebase failure ''
-test_run_rebase failure -m
-test_run_rebase failure -i
+test_run_rebase success ''
+test_run_rebase success -m
+test_run_rebase success -i
 test_run_rebase failure -p
 
 test_run_rebase () {
diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
index 9fc4648..78f7c99 100755
--- a/t/t3430-rebase-merges.sh
+++ b/t/t3430-rebase-merges.sh
@@ -241,6 +241,78 @@
 	test_cmp_rev HEAD $before
 '
 
+test_expect_success 'root commits' '
+	git checkout --orphan unrelated &&
+	(GIT_AUTHOR_NAME="Parsnip" GIT_AUTHOR_EMAIL="root@example.com" \
+	 test_commit second-root) &&
+	test_commit third-root &&
+	cat >script-from-scratch <<-\EOF &&
+	pick third-root
+	label first-branch
+	reset [new root]
+	pick second-root
+	merge first-branch # Merge the 3rd root
+	EOF
+	test_config sequence.editor \""$PWD"/replace-editor.sh\" &&
+	test_tick &&
+	git rebase -i --force --root -r &&
+	test "Parsnip" = "$(git show -s --format=%an HEAD^)" &&
+	test $(git rev-parse second-root^0) != $(git rev-parse HEAD^) &&
+	test $(git rev-parse second-root:second-root.t) = \
+		$(git rev-parse HEAD^:second-root.t) &&
+	test_cmp_graph HEAD <<-\EOF &&
+	*   Merge the 3rd root
+	|\
+	| * third-root
+	* second-root
+	EOF
+
+	: fast forward if possible &&
+	before="$(git rev-parse --verify HEAD)" &&
+	test_might_fail git config --unset sequence.editor &&
+	test_tick &&
+	git rebase -i --root -r &&
+	test_cmp_rev HEAD $before
+'
+
+test_expect_success 'a "merge" into a root commit is a fast-forward' '
+	head=$(git rev-parse HEAD) &&
+	cat >script-from-scratch <<-EOF &&
+	reset [new root]
+	merge $head
+	EOF
+	test_config sequence.editor \""$PWD"/replace-editor.sh\" &&
+	test_tick &&
+	git rebase -i -r HEAD^ &&
+	test_cmp_rev HEAD $head
+'
+
+test_expect_success 'A root commit can be a cousin, treat it that way' '
+	git checkout --orphan khnum &&
+	test_commit yama &&
+	git checkout -b asherah master &&
+	test_commit shamkat &&
+	git merge --allow-unrelated-histories khnum &&
+	test_tick &&
+	git rebase -f -r HEAD^ &&
+	! test_cmp_rev HEAD^2 khnum &&
+	test_cmp_graph HEAD^.. <<-\EOF &&
+	*   Merge branch '\''khnum'\'' into asherah
+	|\
+	| * yama
+	o shamkat
+	EOF
+	test_tick &&
+	git rebase --rebase-merges=rebase-cousins HEAD^ &&
+	test_cmp_graph HEAD^.. <<-\EOF
+	*   Merge branch '\''khnum'\'' into asherah
+	|\
+	| * yama
+	|/
+	o shamkat
+	EOF
+'
+
 test_expect_success 'labels that are object IDs are rewritten' '
 	git checkout -b third B &&
 	test_commit I &&
diff --git a/t/t3501-revert-cherry-pick.sh b/t/t3501-revert-cherry-pick.sh
index ccbc118..d1c68af 100755
--- a/t/t3501-revert-cherry-pick.sh
+++ b/t/t3501-revert-cherry-pick.sh
@@ -141,7 +141,7 @@
 	test_cmp expect actual
 '
 
-test_expect_failure 'cherry-pick works with dirty renamed file' '
+test_expect_success 'cherry-pick works with dirty renamed file' '
 	test_commit to-rename &&
 	git checkout -b unrelated &&
 	test_commit unrelated &&
@@ -150,9 +150,8 @@
 	test_tick &&
 	git commit -m renamed &&
 	echo modified >renamed &&
-	test_must_fail git cherry-pick refs/heads/unrelated >out &&
-	test_i18ngrep "Refusing to lose dirty file at renamed" out &&
-	test $(git rev-parse :0:renamed) = $(git rev-parse HEAD^:to-rename.t) &&
+	git cherry-pick refs/heads/unrelated >out &&
+	test $(git rev-parse :0:renamed) = $(git rev-parse HEAD~2:to-rename.t) &&
 	grep -q "^modified$" renamed
 '
 
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index 21b4f19..b42cd66 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -122,7 +122,7 @@
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
-		sed "s/$_x40/OBJID/g"
+		sed "s/$OID_REGEX/OBJID/g"
 	} >actual &&
 	test_cmp expect actual
 '
@@ -220,7 +220,7 @@
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
-		sed "s/$_x40/OBJID/g"
+		sed "s/$OID_REGEX/OBJID/g"
 	} >actual &&
 	cat >expect <<-\EOF &&
 	OBJID
@@ -317,7 +317,7 @@
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
-		sed "s/$_x40/OBJID/g"
+		sed "s/$OID_REGEX/OBJID/g"
 	} >actual.log &&
 	test_cmp expect foo &&
 	test_cmp expect.log actual.log
@@ -334,7 +334,7 @@
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
-		sed "s/$_x40/OBJID/g"
+		sed "s/$OID_REGEX/OBJID/g"
 	} >actual &&
 	cat >expect <<-\EOF &&
 	OBJID
diff --git a/t/t3702-add-edit.sh b/t/t3702-add-edit.sh
index 3cb74ca..c6af7f8 100755
--- a/t/t3702-add-edit.sh
+++ b/t/t3702-add-edit.sh
@@ -40,7 +40,6 @@
 
 cat > expected-patch << EOF
 diff --git a/file b/file
-index b9834b5..9020acb 100644
 --- a/file
 +++ b/file
 @@ -1,11 +1,6 @@
@@ -80,7 +79,6 @@
 
 cat > expected << EOF
 diff --git a/file b/file
-index b9834b5..ef6e94c 100644
 --- a/file
 +++ b/file
 @@ -1,10 +1,12 @@
@@ -100,7 +98,7 @@
 
 echo "#!$SHELL_PATH" >fake-editor.sh
 cat >> fake-editor.sh <<\EOF
-mv -f "$1" orig-patch &&
+egrep -v '^index' "$1" >orig-patch &&
 mv -f patch "$1"
 EOF
 
@@ -113,7 +111,8 @@
 	git add -e &&
 	test_cmp second-part file &&
 	test_cmp orig-patch expected-patch &&
-	git diff --cached > out &&
+	git diff --cached >actual &&
+	grep -v index actual >out &&
 	test_cmp out expected
 
 '
diff --git a/t/t3903-stash.sh b/t/t3903-stash.sh
index aefde7b..1f871d3 100755
--- a/t/t3903-stash.sh
+++ b/t/t3903-stash.sh
@@ -726,7 +726,7 @@
 	git reset --hard &&
 	! grep quux bazzy &&
 	git stash store -m quuxery $STASH_ID &&
-	test $(cat .git/refs/stash) = $STASH_ID &&
+	test $(git rev-parse stash) = $STASH_ID &&
 	git reflog --format=%H stash| grep $STASH_ID &&
 	git stash pop &&
 	grep quux bazzy
diff --git a/t/t3905-stash-include-untracked.sh b/t/t3905-stash-include-untracked.sh
index 3ea5b9b..597b063 100755
--- a/t/t3905-stash-include-untracked.sh
+++ b/t/t3905-stash-include-untracked.sh
@@ -35,24 +35,26 @@
 	test_cmp expect actual
 '
 
+tracked=$(git rev-parse --short $(echo 1 | git hash-object --stdin))
+untracked=$(git rev-parse --short $(echo untracked | git hash-object --stdin))
 cat > expect.diff <<EOF
 diff --git a/HEAD b/HEAD
 new file mode 100644
-index 0000000..d00491f
+index 0000000..$tracked
 --- /dev/null
 +++ b/HEAD
 @@ -0,0 +1 @@
 +1
 diff --git a/file2 b/file2
 new file mode 100644
-index 0000000..d00491f
+index 0000000..$tracked
 --- /dev/null
 +++ b/file2
 @@ -0,0 +1 @@
 +1
 diff --git a/untracked/untracked b/untracked/untracked
 new file mode 100644
-index 0000000..5a72eb2
+index 0000000..$untracked
 --- /dev/null
 +++ b/untracked/untracked
 @@ -0,0 +1 @@
@@ -109,10 +111,11 @@
 	git stash -u
 '
 
+blob=$(git rev-parse --short $(echo 4 | git hash-object --stdin))
 cat > expect <<EOF
 diff --git a/file3 b/file3
 new file mode 100644
-index 0000000..b8626c4
+index 0000000..$blob
 --- /dev/null
 +++ b/file3
 @@ -0,0 +1 @@
diff --git a/t/t4001-diff-rename.sh b/t/t4001-diff-rename.sh
index a07816d..bf40303 100755
--- a/t/t4001-diff-rename.sh
+++ b/t/t4001-diff-rename.sh
@@ -138,6 +138,18 @@
 	test_i18ngrep "renamed: .*path1 -> subdir/path1" out
 '
 
+test_expect_success 'test diff.renames=true for git status' '
+	git -c diff.renames=true status >out &&
+	test_i18ngrep "renamed: .*path1 -> subdir/path1" out
+'
+
+test_expect_success 'test diff.renames=false for git status' '
+	git -c diff.renames=false status >out &&
+	test_i18ngrep ! "renamed: .*path1 -> subdir/path1" out &&
+	test_i18ngrep "new file: .*subdir/path1" out &&
+	test_i18ngrep "deleted: .*[^/]path1" out
+'
+
 test_expect_success 'favour same basenames even with minor differences' '
 	git show HEAD:path1 | sed "s/15/16/" > subdir/path1 &&
 	git status >out &&
diff --git a/t/t4002-diff-basic.sh b/t/t4002-diff-basic.sh
index a5e8b83..3a6c21e 100755
--- a/t/t4002-diff-basic.sh
+++ b/t/t4002-diff-basic.sh
@@ -131,7 +131,7 @@
     # object ID for the changed files because it wants you to look at the
     # filesystem.
     sed <"$2" >.test-tmp \
-	-e '/^:000000 /d;s/'$_x40'\( [MCRNDU][0-9]*\)	/'$_z40'\1	/' &&
+	-e '/^:000000 /d;s/'$OID_REGEX'\( [MCRNDU][0-9]*\)	/'$ZERO_OID'\1	/' &&
     test_cmp "$1" .test-tmp
 }
 
diff --git a/t/t4006-diff-mode.sh b/t/t4006-diff-mode.sh
index 76f643b..a8e01ec 100755
--- a/t/t4006-diff-mode.sh
+++ b/t/t4006-diff-mode.sh
@@ -8,7 +8,7 @@
 '
 . ./test-lib.sh
 
-sed_script='s/\(:100644 100755\) \('"$_x40"'\) \2 /\1 X X /'
+sed_script='s/\(:100644 100755\) \('"$OID_REGEX"'\) \2 /\1 X X /'
 
 test_expect_success 'setup' '
 	echo frotz >rezrov &&
diff --git a/t/t4007-rename-3.sh b/t/t4007-rename-3.sh
index dae327f..b187b7f 100755
--- a/t/t4007-rename-3.sh
+++ b/t/t4007-rename-3.sh
@@ -17,6 +17,7 @@
 	echo $tree
 '
 
+blob=$(git hash-object "$TEST_DIRECTORY/diff-lib/COPYING")
 test_expect_success 'prepare work tree' '
 	cp path0/COPYING path1/COPYING &&
 	git update-index --add --remove path0/COPYING path1/COPYING
@@ -26,8 +27,8 @@
 # path1 both have COPYING and the latter is a copy of path0/COPYING.
 # Comparing the full tree with cache should tell us so.
 
-cat >expected <<\EOF
-:100644 100644 6ff87c4664981e4397625791c8ea3bbb5f2279a3 6ff87c4664981e4397625791c8ea3bbb5f2279a3 C100	path0/COPYING	path1/COPYING
+cat >expected <<EOF
+:100644 100644 $blob $blob C100	path0/COPYING	path1/COPYING
 EOF
 
 test_expect_success 'copy detection' '
@@ -46,8 +47,8 @@
 # path1/COPYING suddenly appearing from nowhere, not detected as
 # a copy from path0/COPYING.
 
-cat >expected <<\EOF
-:000000 100644 0000000000000000000000000000000000000000 6ff87c4664981e4397625791c8ea3bbb5f2279a3 A	path1/COPYING
+cat >expected <<EOF
+:000000 100644 $ZERO_OID $blob A	path1/COPYING
 EOF
 
 test_expect_success 'copy, limited to a subtree' '
@@ -64,8 +65,8 @@
 # path0/COPYING.  Showing the full tree with cache should tell us about
 # the rename.
 
-cat >expected <<\EOF
-:100644 100644 6ff87c4664981e4397625791c8ea3bbb5f2279a3 6ff87c4664981e4397625791c8ea3bbb5f2279a3 R100	path0/COPYING	path1/COPYING
+cat >expected <<EOF
+:100644 100644 $blob $blob R100	path0/COPYING	path1/COPYING
 EOF
 
 test_expect_success 'rename detection' '
@@ -78,8 +79,8 @@
 # path0/COPYING.  When we say we care only about path1, we should just
 # see path1/COPYING appearing from nowhere.
 
-cat >expected <<\EOF
-:000000 100644 0000000000000000000000000000000000000000 6ff87c4664981e4397625791c8ea3bbb5f2279a3 A	path1/COPYING
+cat >expected <<EOF
+:000000 100644 $ZERO_OID $blob A	path1/COPYING
 EOF
 
 test_expect_success 'rename, limited to a subtree' '
diff --git a/t/t4008-diff-break-rewrite.sh b/t/t4008-diff-break-rewrite.sh
index 9dd1bc5..b1ccd41 100755
--- a/t/t4008-diff-break-rewrite.sh
+++ b/t/t4008-diff-break-rewrite.sh
@@ -27,29 +27,32 @@
 test_expect_success setup '
 	cat "$TEST_DIRECTORY"/diff-lib/README >file0 &&
 	cat "$TEST_DIRECTORY"/diff-lib/COPYING >file1 &&
+	blob0_id=$(git hash-object file0) &&
+	blob1_id=$(git hash-object file1) &&
 	git update-index --add file0 file1 &&
 	git tag reference $(git write-tree)
 '
 
 test_expect_success 'change file1 with copy-edit of file0 and remove file0' '
 	sed -e "s/git/GIT/" file0 >file1 &&
+	blob2_id=$(git hash-object file1) &&
 	rm -f file0 &&
 	git update-index --remove file0 file1
 '
 
 test_expect_success 'run diff with -B (#1)' '
 	git diff-index -B --cached reference >current &&
-	cat >expect <<-\EOF &&
-	:100644 000000 548142c327a6790ff8821d67c2ee1eff7a656b52 0000000000000000000000000000000000000000 D	file0
-	:100644 100644 6ff87c4664981e4397625791c8ea3bbb5f2279a3 2fbedd0b5d4b8126e4750c3bee305e8ff79f80ec M100	file1
+	cat >expect <<-EOF &&
+	:100644 000000 $blob0_id $ZERO_OID D	file0
+	:100644 100644 $blob1_id $blob2_id M100	file1
 	EOF
 	compare_diff_raw expect current
 '
 
 test_expect_success 'run diff with -B and -M (#2)' '
 	git diff-index -B -M reference >current &&
-	cat >expect <<-\EOF &&
-	:100644 100644 548142c327a6790ff8821d67c2ee1eff7a656b52 2fbedd0b5d4b8126e4750c3bee305e8ff79f80ec R100	file0	file1
+	cat >expect <<-EOF &&
+	:100644 100644 $blob0_id $blob2_id R100	file0	file1
 	EOF
 	compare_diff_raw expect current
 '
@@ -66,18 +69,18 @@
 
 test_expect_success 'run diff with -B (#3)' '
 	git diff-index -B reference >current &&
-	cat >expect <<-\EOF &&
-	:100644 100644 548142c327a6790ff8821d67c2ee1eff7a656b52 6ff87c4664981e4397625791c8ea3bbb5f2279a3 M100	file0
-	:100644 100644 6ff87c4664981e4397625791c8ea3bbb5f2279a3 548142c327a6790ff8821d67c2ee1eff7a656b52 M100	file1
+	cat >expect <<-EOF &&
+	:100644 100644 $blob0_id $blob1_id M100	file0
+	:100644 100644 $blob1_id $blob0_id M100	file1
 	EOF
 	compare_diff_raw expect current
 '
 
 test_expect_success 'run diff with -B and -M (#4)' '
 	git diff-index -B -M reference >current &&
-	cat >expect <<-\EOF &&
-	:100644 100644 6ff87c4664981e4397625791c8ea3bbb5f2279a3 6ff87c4664981e4397625791c8ea3bbb5f2279a3 R100	file1	file0
-	:100644 100644 548142c327a6790ff8821d67c2ee1eff7a656b52 548142c327a6790ff8821d67c2ee1eff7a656b52 R100	file0	file1
+	cat >expect <<-EOF &&
+	:100644 100644 $blob1_id $blob1_id R100	file1	file0
+	:100644 100644 $blob0_id $blob0_id R100	file0	file1
 	EOF
 	compare_diff_raw expect current
 '
@@ -85,14 +88,15 @@
 test_expect_success 'make file0 into something completely different' '
 	rm -f file0 &&
 	test_ln_s_add frotz file0 &&
+	slink_id=$(printf frotz | git hash-object --stdin) &&
 	git update-index file1
 '
 
 test_expect_success 'run diff with -B (#5)' '
 	git diff-index -B reference >current &&
-	cat >expect <<-\EOF &&
-	:100644 120000 548142c327a6790ff8821d67c2ee1eff7a656b52 67be421f88824578857624f7b3dc75e99a8a1481 T	file0
-	:100644 100644 6ff87c4664981e4397625791c8ea3bbb5f2279a3 548142c327a6790ff8821d67c2ee1eff7a656b52 M100	file1
+	cat >expect <<-EOF &&
+	:100644 120000 $blob0_id $slink_id T	file0
+	:100644 100644 $blob1_id $blob0_id M100	file1
 	EOF
 	compare_diff_raw expect current
 '
@@ -103,9 +107,9 @@
 	# file0 changed from regular to symlink.  file1 is the same as the preimage
 	# of file0.  Because the change does not make file0 disappear, file1 is
 	# denoted as a copy of file0
-	cat >expect <<-\EOF &&
-	:100644 120000 548142c327a6790ff8821d67c2ee1eff7a656b52 67be421f88824578857624f7b3dc75e99a8a1481 T	file0
-	:100644 100644 548142c327a6790ff8821d67c2ee1eff7a656b52 548142c327a6790ff8821d67c2ee1eff7a656b52 C	file0	file1
+	cat >expect <<-EOF &&
+	:100644 120000 $blob0_id $slink_id T	file0
+	:100644 100644 $blob0_id $blob0_id C	file0	file1
 	EOF
 	compare_diff_raw expect current
 '
@@ -115,9 +119,9 @@
 
 	# This should not mistake file0 as the copy source of new file1
 	# due to type differences.
-	cat >expect <<-\EOF &&
-	:100644 120000 548142c327a6790ff8821d67c2ee1eff7a656b52 67be421f88824578857624f7b3dc75e99a8a1481 T	file0
-	:100644 100644 6ff87c4664981e4397625791c8ea3bbb5f2279a3 548142c327a6790ff8821d67c2ee1eff7a656b52 M	file1
+	cat >expect <<-EOF &&
+	:100644 120000 $blob0_id $slink_id T	file0
+	:100644 100644 $blob1_id $blob0_id M	file1
 	EOF
 	compare_diff_raw expect current
 '
@@ -128,25 +132,26 @@
 	git checkout-index -f -u -a &&
 	sed -e "s/git/GIT/" file0 >file1 &&
 	sed -e "s/git/GET/" file0 >file2 &&
+	blob3_id=$(git hash-object file2) &&
 	rm -f file0 &&
 	git update-index --add --remove file0 file1 file2
 '
 
 test_expect_success 'run diff with -B (#8)' '
 	git diff-index -B reference >current &&
-	cat >expect <<-\EOF &&
-	:100644 000000 548142c327a6790ff8821d67c2ee1eff7a656b52 0000000000000000000000000000000000000000 D	file0
-	:100644 100644 6ff87c4664981e4397625791c8ea3bbb5f2279a3 2fbedd0b5d4b8126e4750c3bee305e8ff79f80ec M100	file1
-	:000000 100644 0000000000000000000000000000000000000000 69a939f651686f56322566e2fd76715947a24162 A	file2
+	cat >expect <<-EOF &&
+	:100644 000000 $blob0_id $ZERO_OID D	file0
+	:100644 100644 $blob1_id $blob2_id M100	file1
+	:000000 100644 $ZERO_OID $blob3_id A	file2
 	EOF
 	compare_diff_raw expect current
 '
 
 test_expect_success 'run diff with -B -C (#9)' '
 	git diff-index -B -C reference >current &&
-	cat >expect <<-\EOF &&
-	:100644 100644 548142c327a6790ff8821d67c2ee1eff7a656b52 2fbedd0b5d4b8126e4750c3bee305e8ff79f80ec C095	file0	file1
-	:100644 100644 548142c327a6790ff8821d67c2ee1eff7a656b52 69a939f651686f56322566e2fd76715947a24162 R095	file0	file2
+	cat >expect <<-EOF &&
+	:100644 100644 $blob0_id $blob2_id C095	file0	file1
+	:100644 100644 $blob0_id $blob3_id R095	file0	file2
 	EOF
 	compare_diff_raw expect current
 '
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index 482112c..028d550 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -578,7 +578,11 @@
 
 	rm -rf patches/ &&
 	git checkout side &&
+	before=$(git hash-object file) &&
+	before=$(git rev-parse --short $before) &&
 	for i in 5 6 1 2 3 A 4 B C 7 8 9 10 D E F; do echo "$i"; done >>file &&
+	after=$(git hash-object file) &&
+	after=$(git rev-parse --short $after) &&
 	git update-index file &&
 	git commit -m "This is an excessively long subject line for a message due to the habit some projects have of not having a short, one-line subject at the start of the commit message, but rather sticking a whole paragraph right at the start as the only thing in the commit message. It had better not become the filename for the patch." &&
 	git format-patch -o patches/ master..side &&
@@ -586,7 +590,6 @@
 '
 
 test_expect_success 'cover-letter inherits diff options' '
-
 	git mv file foo &&
 	git commit -m foo &&
 	git format-patch --no-renames --cover-letter -1 &&
@@ -616,7 +619,7 @@
 '
 
 cat > expect << EOF
-index 40f36c6..2dc5c23 100644
+index $before..$after 100644
 --- a/file
 +++ b/file
 @@ -13,4 +13,20 @@ C
@@ -640,7 +643,7 @@
 cat > expect << EOF
 
 diff --git a/file b/file
-index 40f36c6..2dc5c23 100644
+index $before..$after 100644
 --- a/file
 +++ b/file
 @@ -14,3 +14,19 @@ C
@@ -1523,14 +1526,14 @@
 test_expect_success 'format-patch --zero-commit' '
 	git format-patch --zero-commit --stdout v2..v1 >patch2 &&
 	grep "^From " patch2 | sort | uniq >actual &&
-	echo "From $_z40 Mon Sep 17 00:00:00 2001" >expect &&
+	echo "From $ZERO_OID Mon Sep 17 00:00:00 2001" >expect &&
 	test_cmp expect actual
 '
 
 test_expect_success 'From line has expected format' '
 	git format-patch --stdout v2..v1 >patch2 &&
 	grep "^From " patch2 >from &&
-	grep "^From $_x40 Mon Sep 17 00:00:00 2001$" patch2 >filtered &&
+	grep "^From $OID_REGEX Mon Sep 17 00:00:00 2001$" patch2 >filtered &&
 	test_cmp from filtered
 '
 
@@ -1661,6 +1664,15 @@
 	test_write_lines 1 2 >expect &&
 	test_cmp expect actual
 '
+test_expect_success 'format-patch --attach cover-letter only is non-multipart' '
+	test_when_finished "rm -fr patches" &&
+	git format-patch -o patches --cover-letter --attach=mimemime --base=HEAD~ -1 &&
+	! egrep "^--+mimemime" patches/0000*.patch &&
+	egrep "^--+mimemime$" patches/0001*.patch >output &&
+	test_line_count = 2 output &&
+	egrep "^--+mimemime--$" patches/0001*.patch >output &&
+	test_line_count = 1 output
+'
 
 test_expect_success 'format-patch --pretty=mboxrd' '
 	sp=" " &&
diff --git a/t/t4020-diff-external.sh b/t/t4020-diff-external.sh
index 0446201..e009826 100755
--- a/t/t4020-diff-external.sh
+++ b/t/t4020-diff-external.sh
@@ -13,6 +13,8 @@
 
 	test_tick &&
 	echo second >file &&
+	before=$(git hash-object file) &&
+	before=$(git rev-parse --short $before) &&
 	git add file &&
 	git commit -m second &&
 
@@ -26,7 +28,7 @@
 		read path oldfile oldhex oldmode newfile newhex newmode &&
 		test "z$path" = zfile &&
 		test "z$oldmode" = z100644 &&
-		test "z$newhex" = "z$_z40" &&
+		test "z$newhex" = "z$ZERO_OID" &&
 		test "z$newmode" = z100644 &&
 		oh=$(git rev-parse --verify HEAD:file) &&
 		test "z$oh" = "z$oldhex"
@@ -55,7 +57,7 @@
 		read path oldfile oldhex oldmode newfile newhex newmode &&
 		test "z$path" = zfile &&
 		test "z$oldmode" = z100644 &&
-		test "z$newhex" = "z$_z40" &&
+		test "z$newhex" = "z$ZERO_OID" &&
 		test "z$newmode" = z120000 &&
 		oh=$(git rev-parse --verify HEAD:file) &&
 		test "z$oh" = "z$oldhex"
@@ -73,7 +75,7 @@
 		read path oldfile oldhex oldmode newfile newhex newmode &&
 		test "z$path" = zfile &&
 		test "z$oldmode" = z100644 &&
-		test "z$newhex" = "z$_z40" &&
+		test "z$newhex" = "z$ZERO_OID" &&
 		test "z$newmode" = z100644 &&
 		oh=$(git rev-parse --verify HEAD:file) &&
 		test "z$oh" = "z$oldhex"
@@ -104,7 +106,7 @@
 		read path oldfile oldhex oldmode newfile newhex newmode &&
 		test "z$path" = zfile &&
 		test "z$oldmode" = z100644 &&
-		test "z$newhex" = "z$_z40" &&
+		test "z$newhex" = "z$ZERO_OID" &&
 		test "z$newmode" = z100644 &&
 		oh=$(git rev-parse --verify HEAD:file) &&
 		test "z$oh" = "z$oldhex"
@@ -137,7 +139,7 @@
 		read path oldfile oldhex oldmode newfile newhex newmode &&
 		test "z$path" = zfile &&
 		test "z$oldmode" = z100644 &&
-		test "z$newhex" = "z$_z40" &&
+		test "z$newhex" = "z$ZERO_OID" &&
 		test "z$newmode" = z100644 &&
 		oh=$(git rev-parse --verify HEAD:file) &&
 		test "z$oh" = "z$oldhex"
@@ -180,9 +182,13 @@
 echo NULZbetweenZwords | perl -pe 'y/Z/\000/' > file
 
 test_expect_success 'force diff with "diff"' '
+	after=$(git hash-object file) &&
+	after=$(git rev-parse --short $after) &&
 	echo >.gitattributes "file diff" &&
 	git diff >actual &&
-	test_cmp "$TEST_DIRECTORY"/t4020/diff.NUL actual
+	sed -e "s/^index .*/index $before..$after 100644/" \
+		"$TEST_DIRECTORY"/t4020/diff.NUL >expected-diff &&
+	test_cmp expected-diff actual
 '
 
 test_expect_success 'GIT_EXTERNAL_DIFF with more than one changed files' '
@@ -237,7 +243,7 @@
 	git update-index --assume-unchanged file &&
 	echo second >file &&
 	git diff --cached >actual &&
-	test_cmp "$TEST_DIRECTORY"/t4020/diff.NUL actual
+	test_cmp expected-diff actual
 '
 
 test_expect_success 'clean up crlf leftovers' '
diff --git a/t/t4022-diff-rewrite.sh b/t/t4022-diff-rewrite.sh
index cb51d9f..6d1c3d9 100755
--- a/t/t4022-diff-rewrite.sh
+++ b/t/t4022-diff-rewrite.sh
@@ -13,6 +13,8 @@
 	  "nopqrstuvwxyzabcdefghijklmNOPQRSTUVWXYZABCDEFGHIJKLM" \
 	  <"$TEST_DIRECTORY"/../COPYING >test &&
 	echo "to be deleted" >test2 &&
+	blob=$(git hash-object test2) &&
+	blob=$(git rev-parse --short $blob) &&
 	git add test2
 
 '
@@ -27,7 +29,7 @@
 cat >expect <<EOF
 diff --git a/test2 b/test2
 deleted file mode 100644
-index 4202011..0000000
+index $blob..0000000
 --- a/test2
 +++ /dev/null
 @@ -1 +0,0 @@
@@ -43,7 +45,7 @@
 cat >expect <<EOF
 diff --git a/test2 b/test2
 deleted file mode 100644
-index 4202011..0000000
+index $blob..0000000
 EOF
 test_expect_success 'suppress deletion diff with -D' '
 
diff --git a/t/t4027-diff-submodule.sh b/t/t4027-diff-submodule.sh
index 2ffd11a..6304130 100755
--- a/t/t4027-diff-submodule.sh
+++ b/t/t4027-diff-submodule.sh
@@ -31,7 +31,7 @@
 		cd sub &&
 		git rev-list HEAD
 	) &&
-	echo ":160000 160000 $3 $_z40 M	sub" >expect &&
+	echo ":160000 160000 $3 $ZERO_OID M	sub" >expect &&
 	subtip=$3 subprev=$2
 '
 
@@ -250,7 +250,7 @@
 	# 39 efs
 	c=fffffffffffffffffffffffffffffffffffffff &&
 	(
-		echo "000000 $_z40 0	sub" &&
+		echo "000000 $ZERO_OID 0	sub" &&
 		echo "160000 1$c 1	sub" &&
 		echo "160000 2$c 2	sub" &&
 		echo "160000 3$c 3	sub"
@@ -265,7 +265,7 @@
 ++Subproject commit 0000000000000000000000000000000000000000'\'' &&
 
 	hh=$(git rev-parse HEAD) &&
-	sed -e "s/$_z40/$hh/" expect.nosub >expect.withsub
+	sed -e "s/$ZERO_OID/$hh/" expect.nosub >expect.withsub
 
 '
 
diff --git a/t/t4029-diff-trailing-space.sh b/t/t4029-diff-trailing-space.sh
index 3ccc237..32b6e9a 100755
--- a/t/t4029-diff-trailing-space.sh
+++ b/t/t4029-diff-trailing-space.sh
@@ -6,7 +6,7 @@
 
 . ./test-lib.sh
 
-cat <<\EOF > exp ||
+cat <<\EOF >expected ||
 diff --git a/f b/f
 index 5f6a263..8cb8bae 100644
 --- a/f
@@ -18,22 +18,26 @@
 EOF
 exit 1
 
-test_expect_success \
-    "$test_description" \
-    'printf "\nx\n" > f &&
-     git add f &&
-     git commit -q -m. f &&
-     printf "\ny\n" > f &&
-     git config --bool diff.suppressBlankEmpty true &&
-     git diff f > actual &&
-     test_cmp exp actual &&
-     perl -i.bak -p -e "s/^\$/ /" exp &&
-     git config --bool diff.suppressBlankEmpty false &&
-     git diff f > actual &&
-     test_cmp exp actual &&
-     git config --bool --unset diff.suppressBlankEmpty &&
-     git diff f > actual &&
-     test_cmp exp actual
-     '
+test_expect_success "$test_description" '
+	printf "\nx\n" > f &&
+	before=$(git hash-object f) &&
+	before=$(git rev-parse --short $before) &&
+	git add f &&
+	git commit -q -m. f &&
+	printf "\ny\n" > f &&
+	after=$(git hash-object f) &&
+	after=$(git rev-parse --short $after) &&
+	sed -e "s/^index .*/index $before..$after 100644/" expected >exp &&
+	git config --bool diff.suppressBlankEmpty true &&
+	git diff f > actual &&
+	test_cmp exp actual &&
+	perl -i.bak -p -e "s/^\$/ /" exp &&
+	git config --bool diff.suppressBlankEmpty false &&
+	git diff f > actual &&
+	test_cmp exp actual &&
+	git config --bool --unset diff.suppressBlankEmpty &&
+	git diff f > actual &&
+	test_cmp exp actual
+'
 
 test_done
diff --git a/t/t4030-diff-textconv.sh b/t/t4030-diff-textconv.sh
index aad6c7f..4cb9f0e 100755
--- a/t/t4030-diff-textconv.sh
+++ b/t/t4030-diff-textconv.sh
@@ -148,7 +148,8 @@
 # restore working setup
 echo file diff=foo >.gitattributes
 
-cat >expect.typechange <<'EOF'
+symlink=$(git rev-parse --short $(printf frotz | git hash-object --stdin))
+cat >expect.typechange <<EOF
 --- a/file
 +++ /dev/null
 @@ -1,2 +0,0 @@
@@ -156,7 +157,7 @@
 -1
 diff --git a/file b/file
 new file mode 120000
-index 0000000..67be421
+index 0000000..$symlink
 --- /dev/null
 +++ b/file
 @@ -0,0 +1 @@
diff --git a/t/t4042-diff-textconv-caching.sh b/t/t4042-diff-textconv-caching.sh
index 04a44d5..bf33aed 100755
--- a/t/t4042-diff-textconv-caching.sh
+++ b/t/t4042-diff-textconv-caching.sh
@@ -15,9 +15,13 @@
 	echo bar content 1 >bar.bin &&
 	git add . &&
 	git commit -m one &&
+	foo1=$(git rev-parse --short HEAD:foo.bin) &&
+	bar1=$(git rev-parse --short HEAD:bar.bin) &&
 	echo foo content 2 >foo.bin &&
 	echo bar content 2 >bar.bin &&
 	git commit -a -m two &&
+	foo2=$(git rev-parse --short HEAD:foo.bin) &&
+	bar2=$(git rev-parse --short HEAD:bar.bin) &&
 	echo "*.bin diff=magic" >.gitattributes &&
 	git config diff.magic.textconv ./helper &&
 	git config diff.magic.cachetextconv true
@@ -25,14 +29,14 @@
 
 cat >expect <<EOF
 diff --git a/bar.bin b/bar.bin
-index fcf9166..28283d5 100644
+index $bar1..$bar2 100644
 --- a/bar.bin
 +++ b/bar.bin
 @@ -1 +1 @@
 -converted: bar content 1
 +converted: bar content 2
 diff --git a/foo.bin b/foo.bin
-index d5b9fe3..1345db2 100644
+index $foo1..$foo2 100644
 --- a/foo.bin
 +++ b/foo.bin
 @@ -1 +1 @@
@@ -59,7 +63,7 @@
 
 cat >expect <<EOF
 diff --git a/bar.bin b/bar.bin
-index fcf9166..28283d5 100644
+index $bar1..$bar2 100644
 --- a/bar.bin
 +++ b/bar.bin
 @@ -1,2 +1,2 @@
@@ -67,7 +71,7 @@
 -converted: bar content 1
 +converted: bar content 2
 diff --git a/foo.bin b/foo.bin
-index d5b9fe3..1345db2 100644
+index $foo1..$foo2 100644
 --- a/foo.bin
 +++ b/foo.bin
 @@ -1,2 +1,2 @@
@@ -84,7 +88,7 @@
 
 cat >expect <<EOF
 diff --git a/bar.bin b/bar.bin
-index fcf9166..28283d5 100644
+index $bar1..$bar2 100644
 --- a/bar.bin
 +++ b/bar.bin
 @@ -1,2 +1,2 @@
@@ -92,7 +96,7 @@
 -converted: bar content 1
 +converted: bar content 2
 diff --git a/foo.bin b/foo.bin
-index d5b9fe3..1345db2 100644
+index $foo1..$foo2 100644
 --- a/foo.bin
 +++ b/foo.bin
 @@ -1 +1 @@
diff --git a/t/t4044-diff-index-unique-abbrev.sh b/t/t4044-diff-index-unique-abbrev.sh
index d5ce72b..647905e 100755
--- a/t/t4044-diff-index-unique-abbrev.sh
+++ b/t/t4044-diff-index-unique-abbrev.sh
@@ -3,6 +3,12 @@
 test_description='test unique sha1 abbreviation on "index from..to" line'
 . ./test-lib.sh
 
+if ! test_have_prereq SHA1
+then
+       skip_all='not using SHA-1 for objects'
+       test_done
+fi
+
 cat >expect_initial <<EOF
 100644 blob 51d2738463ea4ca66f8691c91e33ce64b7d41bb1	foo
 EOF
diff --git a/t/t4045-diff-relative.sh b/t/t4045-diff-relative.sh
index 6471a68..36f8ed8 100755
--- a/t/t4045-diff-relative.sh
+++ b/t/t4045-diff-relative.sh
@@ -8,6 +8,7 @@
 	echo content >file1 &&
 	mkdir subdir &&
 	echo other content >subdir/file2 &&
+	blob=$(git hash-object subdir/file2) &&
 	git add . &&
 	git commit -m one
 '
@@ -17,10 +18,11 @@
 	shift
 	expect=$1
 	shift
+	short_blob=$(git rev-parse --short $blob)
 	cat >expected <<-EOF
 	diff --git a/$expect b/$expect
 	new file mode 100644
-	index 0000000..25c05ef
+	index 0000000..$short_blob
 	--- /dev/null
 	+++ b/$expect
 	@@ -0,0 +1 @@
@@ -68,7 +70,7 @@
 	expect=$1
 	shift
 	cat >expected <<-EOF
-	:000000 100644 0000000000000000000000000000000000000000 25c05ef3639d2d270e7fe765a67668f098092bc5 A	$expect
+	:000000 100644 0000000000000000000000000000000000000000 $blob A	$expect
 	EOF
 	test_expect_success "--raw $*" "
 		git -C '$dir' diff --no-abbrev --raw $* HEAD^ >actual &&
diff --git a/t/t4046-diff-unmerged.sh b/t/t4046-diff-unmerged.sh
index d0f1447..ff7cfd8 100755
--- a/t/t4046-diff-unmerged.sh
+++ b/t/t4046-diff-unmerged.sh
@@ -37,7 +37,7 @@
 	for path in $paths
 	do
 		>"$path" &&
-		echo ":000000 100644 $_z40 $_z40 U	$path"
+		echo ":000000 100644 $ZERO_OID $ZERO_OID U	$path"
 	done >diff-files-0.expect &&
 	git diff-files -0 >diff-files-0.actual &&
 	test_cmp diff-files-0.expect diff-files-0.actual
@@ -47,9 +47,9 @@
 	for path in $paths
 	do
 		>"$path" &&
-		echo ":000000 100644 $_z40 $_z40 U	$path" &&
+		echo ":000000 100644 $ZERO_OID $ZERO_OID U	$path" &&
 		case "$path" in
-		x??) echo ":100644 100644 $blob1 $_z40 M	$path"
+		x??) echo ":100644 100644 $blob1 $ZERO_OID M	$path"
 		esac
 	done >diff-files-1.expect &&
 	git diff-files -1 >diff-files-1.actual &&
@@ -60,9 +60,9 @@
 	for path in $paths
 	do
 		>"$path" &&
-		echo ":000000 100644 $_z40 $_z40 U	$path" &&
+		echo ":000000 100644 $ZERO_OID $ZERO_OID U	$path" &&
 		case "$path" in
-		?x?) echo ":100644 100644 $blob2 $_z40 M	$path"
+		?x?) echo ":100644 100644 $blob2 $ZERO_OID M	$path"
 		esac
 	done >diff-files-2.expect &&
 	git diff-files -2 >diff-files-2.actual &&
@@ -75,9 +75,9 @@
 	for path in $paths
 	do
 		>"$path" &&
-		echo ":000000 100644 $_z40 $_z40 U	$path" &&
+		echo ":000000 100644 $ZERO_OID $ZERO_OID U	$path" &&
 		case "$path" in
-		??x) echo ":100644 100644 $blob3 $_z40 M	$path"
+		??x) echo ":100644 100644 $blob3 $ZERO_OID M	$path"
 		esac
 	done >diff-files-3.expect &&
 	git diff-files -3 >diff-files-3.actual &&
diff --git a/t/t4054-diff-bogus-tree.sh b/t/t4054-diff-bogus-tree.sh
index 18f42c5..fcae82f 100755
--- a/t/t4054-diff-bogus-tree.sh
+++ b/t/t4054-diff-bogus-tree.sh
@@ -19,37 +19,37 @@
 '
 
 test_expect_success 'raw diff shows null sha1 (addition)' '
-	echo ":000000 100644 $_z40 $_z40 A	foo" >expect &&
+	echo ":000000 100644 $ZERO_OID $ZERO_OID A	foo" >expect &&
 	git diff-tree $EMPTY_TREE $bogus_tree >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success 'raw diff shows null sha1 (removal)' '
-	echo ":100644 000000 $_z40 $_z40 D	foo" >expect &&
+	echo ":100644 000000 $ZERO_OID $ZERO_OID D	foo" >expect &&
 	git diff-tree $bogus_tree $EMPTY_TREE >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success 'raw diff shows null sha1 (modification)' '
-	echo ":100644 100644 $blob $_z40 M	foo" >expect &&
+	echo ":100644 100644 $blob $ZERO_OID M	foo" >expect &&
 	git diff-tree $good_tree $bogus_tree >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success 'raw diff shows null sha1 (other direction)' '
-	echo ":100644 100644 $_z40 $blob M	foo" >expect &&
+	echo ":100644 100644 $ZERO_OID $blob M	foo" >expect &&
 	git diff-tree $bogus_tree $good_tree >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success 'raw diff shows null sha1 (reverse)' '
-	echo ":100644 100644 $_z40 $blob M	foo" >expect &&
+	echo ":100644 100644 $ZERO_OID $blob M	foo" >expect &&
 	git diff-tree -R $good_tree $bogus_tree >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success 'raw diff shows null sha1 (index)' '
-	echo ":100644 100644 $_z40 $blob M	foo" >expect &&
+	echo ":100644 100644 $ZERO_OID $blob M	foo" >expect &&
 	git diff-index $bogus_tree >actual &&
 	test_cmp expect actual
 '
diff --git a/t/t4058-diff-duplicates.sh b/t/t4058-diff-duplicates.sh
index 0a23242..c24ee17 100755
--- a/t/t4058-diff-duplicates.sh
+++ b/t/t4058-diff-duplicates.sh
@@ -59,12 +59,12 @@
 
 test_expect_success 'diff-tree between trees' '
 	{
-		printf ":000000 100644 $_z40 $blob_two A\touter/inner\n" &&
-		printf ":000000 100644 $_z40 $blob_two A\touter/inner\n" &&
-		printf ":000000 100644 $_z40 $blob_two A\touter/inner\n" &&
-		printf ":100644 000000 $blob_two $_z40 D\touter/inner\n" &&
-		printf ":100644 000000 $blob_two $_z40 D\touter/inner\n" &&
-		printf ":100644 000000 $blob_two $_z40 D\touter/inner\n"
+		printf ":000000 100644 $ZERO_OID $blob_two A\touter/inner\n" &&
+		printf ":000000 100644 $ZERO_OID $blob_two A\touter/inner\n" &&
+		printf ":000000 100644 $ZERO_OID $blob_two A\touter/inner\n" &&
+		printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n" &&
+		printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n" &&
+		printf ":100644 000000 $blob_two $ZERO_OID D\touter/inner\n"
 	} >expect &&
 	git diff-tree -r --no-abbrev one two >actual &&
 	test_cmp expect actual
diff --git a/t/t4150-am.sh b/t/t4150-am.sh
index 1eccfb7..1ebc587 100755
--- a/t/t4150-am.sh
+++ b/t/t4150-am.sh
@@ -140,8 +140,8 @@
 		echo "# User $GIT_AUTHOR_NAME <$GIT_AUTHOR_EMAIL>" &&
 		echo "# Date $test_tick 25200" &&
 		echo "#      $(git show --pretty="%aD" -s second)" &&
-		echo "# Node ID $_z40" &&
-		echo "# Parent  $_z40" &&
+		echo "# Node ID $ZERO_OID" &&
+		echo "# Parent  $ZERO_OID" &&
 		cat msg &&
 		echo &&
 		git diff-tree --no-commit-id -p second
diff --git a/t/t4200-rerere.sh b/t/t4200-rerere.sh
index eaf18c8..8417e5a 100755
--- a/t/t4200-rerere.sh
+++ b/t/t4200-rerere.sh
@@ -243,7 +243,7 @@
 	five_days="$1" right_now="$2"
 	test_expect_success "rerere gc with custom expiry ($five_days, $right_now)" '
 		rm -fr .git/rr-cache &&
-		rr=.git/rr-cache/$_z40 &&
+		rr=.git/rr-cache/$ZERO_OID &&
 		mkdir -p "$rr" &&
 		>"$rr/preimage" &&
 		>"$rr/postimage" &&
diff --git a/t/t4201-shortlog.sh b/t/t4201-shortlog.sh
index ff6649e..58c2773 100755
--- a/t/t4201-shortlog.sh
+++ b/t/t4201-shortlog.sh
@@ -59,7 +59,7 @@
 fuzz() {
 	file=$1 &&
 	sed "
-			s/$_x40/OBJECT_NAME/g
+			s/$OID_REGEX/OBJECT_NAME/g
 			s/$_x35/OBJID/g
 			s/^ \{6\}[CTa].*/      SUBJECT/g
 			s/^ \{8\}[^ ].*/        CONTINUATION/g
diff --git a/t/t4205-log-pretty-formats.sh b/t/t4205-log-pretty-formats.sh
index 591f35d..2052cad 100755
--- a/t/t4205-log-pretty-formats.sh
+++ b/t/t4205-log-pretty-formats.sh
@@ -516,22 +516,22 @@
 	git commit --amend -m shorter &&
 	git log --no-walk --tags --pretty="%H %d" --decorate=full >actual &&
 	cat <<-EOF >expected &&
-	$head1  (tag: refs/tags/tag2)
 	$head2  (tag: refs/tags/message-one)
 	$old_head1  (tag: refs/tags/message-two)
+	$head1  (tag: refs/tags/tag2)
 	EOF
-	sort actual >actual1 &&
+	sort -k3 actual >actual1 &&
 	test_cmp expected actual1
 '
 
 test_expect_success 'clean log decoration' '
 	git log --no-walk --tags --pretty="%H %D" --decorate=full >actual &&
 	cat >expected <<-EOF &&
-	$head1 tag: refs/tags/tag2
 	$head2 tag: refs/tags/message-one
 	$old_head1 tag: refs/tags/message-two
+	$head1 tag: refs/tags/tag2
 	EOF
-	sort actual >actual1 &&
+	sort -k3 actual >actual1 &&
 	test_cmp expected actual1
 '
 
diff --git a/t/t4208-log-magic-pathspec.sh b/t/t4208-log-magic-pathspec.sh
index a1705f7..62f335b 100755
--- a/t/t4208-log-magic-pathspec.sh
+++ b/t/t4208-log-magic-pathspec.sh
@@ -45,8 +45,9 @@
 '
 
 test_expect_success 'git log HEAD -- :/' '
+	initial=$(git rev-parse --short HEAD^) &&
 	cat >expected <<-EOF &&
-	24b24cf initial
+	$initial initial
 	EOF
 	(cd sub && git log --oneline HEAD -- :/ >../actual) &&
 	test_cmp expected actual
diff --git a/t/t5150-request-pull.sh b/t/t5150-request-pull.sh
index 08c210f..fca001e 100755
--- a/t/t5150-request-pull.sh
+++ b/t/t5150-request-pull.sh
@@ -81,7 +81,7 @@
 	cat <<-EOT >fuzz.sed
 	#!/bin/sed -nf
 	s/$downstream_url_for_sed/URL/g
-	s/$_x40/OBJECT_NAME/g
+	s/$OID_REGEX/OBJECT_NAME/g
 	s/A U Thor/AUTHOR/g
 	s/[-0-9]\{10\} [:0-9]\{8\} [-+][0-9]\{4\}/DATE/g
 	s/        [^ ].*/        SUBJECT/g
diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh
index 65ff60f..87a590c 100755
--- a/t/t5300-pack-object.sh
+++ b/t/t5300-pack-object.sh
@@ -457,6 +457,11 @@
 	grep -F "no threads support, ignoring pack.threads" err
 '
 
+test_expect_success 'pack-objects in too-many-packs mode' '
+	GIT_TEST_FULL_IN_PACK_ARRAY=1 git repack -ad &&
+	git fsck
+'
+
 #
 # WARNING!
 #
@@ -466,9 +471,11 @@
 
 test_expect_success \
     'fake a SHA1 hash collision' \
-    'test -f	.git/objects/c8/2de19312b6c3695c0c18f70709a6c535682a67 &&
-     cp -f	.git/objects/9d/235ed07cd19811a6ceb342de82f190e49c9f68 \
-		.git/objects/c8/2de19312b6c3695c0c18f70709a6c535682a67'
+    'long_a=$(git hash-object a | sed -e "s!^..!&/!") &&
+     long_b=$(git hash-object b | sed -e "s!^..!&/!") &&
+     test -f	.git/objects/$long_b &&
+     cp -f	.git/objects/$long_a \
+		.git/objects/$long_b'
 
 test_expect_success \
     'make sure index-pack detects the SHA1 collision' \
diff --git a/t/t5304-prune.sh b/t/t5304-prune.sh
index f0f6e2a..f20f03c 100755
--- a/t/t5304-prune.sh
+++ b/t/t5304-prune.sh
@@ -320,4 +320,14 @@
 	test_cmp expected actual
 '
 
+test_expect_success 'prune: handle expire option correctly' '
+	test_must_fail git prune --expire 2>error &&
+	test_i18ngrep "requires a value" error &&
+
+	test_must_fail git prune --expire=nyah 2>error &&
+	test_i18ngrep "malformed expiration" error &&
+
+	git prune --no-expire
+'
+
 test_done
diff --git a/t/t5308-pack-detect-duplicates.sh b/t/t5308-pack-detect-duplicates.sh
index 156ae9e..6845c1f 100755
--- a/t/t5308-pack-detect-duplicates.sh
+++ b/t/t5308-pack-detect-duplicates.sh
@@ -4,6 +4,12 @@
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-pack.sh
 
+if ! test_have_prereq SHA1
+then
+       skip_all='not using SHA-1 for objects'
+       test_done
+fi
+
 # The sha1s we have in our pack. It's important that these have the same
 # starting byte, so that they end up in the same fanout section of the index.
 # That lets us make sure we are exercising the binary search with both sets.
diff --git a/t/t5309-pack-delta-cycles.sh b/t/t5309-pack-delta-cycles.sh
index 3e7861b..491556da 100755
--- a/t/t5309-pack-delta-cycles.sh
+++ b/t/t5309-pack-delta-cycles.sh
@@ -4,6 +4,12 @@
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-pack.sh
 
+if ! test_have_prereq SHA1
+then
+       skip_all='not using SHA-1 for objects'
+       test_done
+fi
+
 # Two similar-ish objects that we have computed deltas between.
 A=01d7713666f4de822776c7622c10f1b07de280dc
 B=e68fe8129b546b101aee9510c5328e7f21ca1d18
diff --git a/t/t5310-pack-bitmaps.sh b/t/t5310-pack-bitmaps.sh
index f6d600f..423c0a4 100755
--- a/t/t5310-pack-bitmaps.sh
+++ b/t/t5310-pack-bitmaps.sh
@@ -264,9 +264,9 @@
 '
 
 test_expect_success JGIT 'we can read jgit bitmaps' '
-	git clone . compat-jgit &&
+	git clone --bare . compat-jgit.git &&
 	(
-		cd compat-jgit &&
+		cd compat-jgit.git &&
 		rm -f .git/objects/pack/*.bitmap &&
 		jgit gc &&
 		git rev-list --test-bitmap HEAD
@@ -274,9 +274,9 @@
 '
 
 test_expect_success JGIT 'jgit can read our bitmaps' '
-	git clone . compat-us &&
+	git clone --bare . compat-us.git &&
 	(
-		cd compat-us &&
+		cd compat-us.git &&
 		git repack -adb &&
 		# jgit gc will barf if it does not like our bitmaps
 		jgit gc
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
new file mode 100755
index 0000000..a380419
--- /dev/null
+++ b/t/t5318-commit-graph.sh
@@ -0,0 +1,224 @@
+#!/bin/sh
+
+test_description='commit graph'
+. ./test-lib.sh
+
+test_expect_success 'setup full repo' '
+	mkdir full &&
+	cd "$TRASH_DIRECTORY/full" &&
+	git init &&
+	git config core.commitGraph true &&
+	objdir=".git/objects"
+'
+
+test_expect_success 'write graph with no packs' '
+	cd "$TRASH_DIRECTORY/full" &&
+	git commit-graph write --object-dir . &&
+	test_path_is_file info/commit-graph
+'
+
+test_expect_success 'create commits and repack' '
+	cd "$TRASH_DIRECTORY/full" &&
+	for i in $(test_seq 3)
+	do
+		test_commit $i &&
+		git branch commits/$i
+	done &&
+	git repack
+'
+
+graph_git_two_modes() {
+	git -c core.graph=true $1 >output
+	git -c core.graph=false $1 >expect
+	test_cmp output expect
+}
+
+graph_git_behavior() {
+	MSG=$1
+	DIR=$2
+	BRANCH=$3
+	COMPARE=$4
+	test_expect_success "check normal git operations: $MSG" '
+		cd "$TRASH_DIRECTORY/$DIR" &&
+		graph_git_two_modes "log --oneline $BRANCH" &&
+		graph_git_two_modes "log --topo-order $BRANCH" &&
+		graph_git_two_modes "log --graph $COMPARE..$BRANCH" &&
+		graph_git_two_modes "branch -vv" &&
+		graph_git_two_modes "merge-base -a $BRANCH $COMPARE"
+	'
+}
+
+graph_git_behavior 'no graph' full commits/3 commits/1
+
+graph_read_expect() {
+	OPTIONAL=""
+	NUM_CHUNKS=3
+	if test ! -z $2
+	then
+		OPTIONAL=" $2"
+		NUM_CHUNKS=$((3 + $(echo "$2" | wc -w)))
+	fi
+	cat >expect <<- EOF
+	header: 43475048 1 1 $NUM_CHUNKS 0
+	num_commits: $1
+	chunks: oid_fanout oid_lookup commit_metadata$OPTIONAL
+	EOF
+	git commit-graph read >output &&
+	test_cmp expect output
+}
+
+test_expect_success 'write graph' '
+	cd "$TRASH_DIRECTORY/full" &&
+	graph1=$(git commit-graph write) &&
+	test_path_is_file $objdir/info/commit-graph &&
+	graph_read_expect "3"
+'
+
+graph_git_behavior 'graph exists' full commits/3 commits/1
+
+test_expect_success 'Add more commits' '
+	cd "$TRASH_DIRECTORY/full" &&
+	git reset --hard commits/1 &&
+	for i in $(test_seq 4 5)
+	do
+		test_commit $i &&
+		git branch commits/$i
+	done &&
+	git reset --hard commits/2 &&
+	for i in $(test_seq 6 7)
+	do
+		test_commit $i &&
+		git branch commits/$i
+	done &&
+	git reset --hard commits/2 &&
+	git merge commits/4 &&
+	git branch merge/1 &&
+	git reset --hard commits/4 &&
+	git merge commits/6 &&
+	git branch merge/2 &&
+	git reset --hard commits/3 &&
+	git merge commits/5 commits/7 &&
+	git branch merge/3 &&
+	git repack
+'
+
+# Current graph structure:
+#
+#   __M3___
+#  /   |   \
+# 3 M1 5 M2 7
+# |/  \|/  \|
+# 2    4    6
+# |___/____/
+# 1
+
+test_expect_success 'write graph with merges' '
+	cd "$TRASH_DIRECTORY/full" &&
+	git commit-graph write &&
+	test_path_is_file $objdir/info/commit-graph &&
+	graph_read_expect "10" "large_edges"
+'
+
+graph_git_behavior 'merge 1 vs 2' full merge/1 merge/2
+graph_git_behavior 'merge 1 vs 3' full merge/1 merge/3
+graph_git_behavior 'merge 2 vs 3' full merge/2 merge/3
+
+test_expect_success 'Add one more commit' '
+	cd "$TRASH_DIRECTORY/full" &&
+	test_commit 8 &&
+	git branch commits/8 &&
+	ls $objdir/pack | grep idx >existing-idx &&
+	git repack &&
+	ls $objdir/pack| grep idx | grep -v --file=existing-idx >new-idx
+'
+
+# Current graph structure:
+#
+#      8
+#      |
+#   __M3___
+#  /   |   \
+# 3 M1 5 M2 7
+# |/  \|/  \|
+# 2    4    6
+# |___/____/
+# 1
+
+graph_git_behavior 'mixed mode, commit 8 vs merge 1' full commits/8 merge/1
+graph_git_behavior 'mixed mode, commit 8 vs merge 2' full commits/8 merge/2
+
+test_expect_success 'write graph with new commit' '
+	cd "$TRASH_DIRECTORY/full" &&
+	git commit-graph write &&
+	test_path_is_file $objdir/info/commit-graph &&
+	graph_read_expect "11" "large_edges"
+'
+
+graph_git_behavior 'full graph, commit 8 vs merge 1' full commits/8 merge/1
+graph_git_behavior 'full graph, commit 8 vs merge 2' full commits/8 merge/2
+
+test_expect_success 'write graph with nothing new' '
+	cd "$TRASH_DIRECTORY/full" &&
+	git commit-graph write &&
+	test_path_is_file $objdir/info/commit-graph &&
+	graph_read_expect "11" "large_edges"
+'
+
+graph_git_behavior 'cleared graph, commit 8 vs merge 1' full commits/8 merge/1
+graph_git_behavior 'cleared graph, commit 8 vs merge 2' full commits/8 merge/2
+
+test_expect_success 'build graph from latest pack with closure' '
+	cd "$TRASH_DIRECTORY/full" &&
+	cat new-idx | git commit-graph write --stdin-packs &&
+	test_path_is_file $objdir/info/commit-graph &&
+	graph_read_expect "9" "large_edges"
+'
+
+graph_git_behavior 'graph from pack, commit 8 vs merge 1' full commits/8 merge/1
+graph_git_behavior 'graph from pack, commit 8 vs merge 2' full commits/8 merge/2
+
+test_expect_success 'build graph from commits with closure' '
+	cd "$TRASH_DIRECTORY/full" &&
+	git tag -a -m "merge" tag/merge merge/2 &&
+	git rev-parse tag/merge >commits-in &&
+	git rev-parse merge/1 >>commits-in &&
+	cat commits-in | git commit-graph write --stdin-commits &&
+	test_path_is_file $objdir/info/commit-graph &&
+	graph_read_expect "6"
+'
+
+graph_git_behavior 'graph from commits, commit 8 vs merge 1' full commits/8 merge/1
+graph_git_behavior 'graph from commits, commit 8 vs merge 2' full commits/8 merge/2
+
+test_expect_success 'build graph from commits with append' '
+	cd "$TRASH_DIRECTORY/full" &&
+	git rev-parse merge/3 | git commit-graph write --stdin-commits --append &&
+	test_path_is_file $objdir/info/commit-graph &&
+	graph_read_expect "10" "large_edges"
+'
+
+graph_git_behavior 'append graph, commit 8 vs merge 1' full commits/8 merge/1
+graph_git_behavior 'append graph, commit 8 vs merge 2' full commits/8 merge/2
+
+test_expect_success 'setup bare repo' '
+	cd "$TRASH_DIRECTORY" &&
+	git clone --bare --no-local full bare &&
+	cd bare &&
+	git config core.commitGraph true &&
+	baredir="./objects"
+'
+
+graph_git_behavior 'bare repo, commit 8 vs merge 1' bare commits/8 merge/1
+graph_git_behavior 'bare repo, commit 8 vs merge 2' bare commits/8 merge/2
+
+test_expect_success 'write graph in bare repo' '
+	cd "$TRASH_DIRECTORY/bare" &&
+	git commit-graph write &&
+	test_path_is_file $baredir/info/commit-graph &&
+	graph_read_expect "11" "large_edges"
+'
+
+graph_git_behavior 'bare repo with graph, commit 8 vs merge 1' bare commits/8 merge/1
+graph_git_behavior 'bare repo with graph, commit 8 vs merge 2' bare commits/8 merge/2
+
+test_done
diff --git a/t/t5500-fetch-pack.sh b/t/t5500-fetch-pack.sh
index 0680dec..d4f4351 100755
--- a/t/t5500-fetch-pack.sh
+++ b/t/t5500-fetch-pack.sh
@@ -30,7 +30,7 @@
 	test_tick &&
 	commit=$(echo "$text" | git commit-tree $tree $parents) &&
 	eval "$name=$commit; export $name" &&
-	echo $commit > .git/refs/heads/$branch &&
+	git update-ref "refs/heads/$branch" "$commit" &&
 	eval ${branch}TIP=$commit
 }
 
@@ -45,10 +45,10 @@
 
 			case "$heads" in
 			    *A*)
-				    echo $ATIP > .git/refs/heads/A;;
+				    git update-ref refs/heads/A "$ATIP";;
 			esac &&
 			case "$heads" in *B*)
-			    echo $BTIP > .git/refs/heads/B;;
+			    git update-ref refs/heads/B "$BTIP";;
 			esac &&
 			git symbolic-ref HEAD refs/heads/$(echo $heads \
 				| sed -e "s/^\(.\).*$/\1/") &&
@@ -92,8 +92,8 @@
 		cur=$(($cur+1))
 	done &&
 	add B1 $A1 &&
-	echo $ATIP > .git/refs/heads/A &&
-	echo $BTIP > .git/refs/heads/B &&
+	git update-ref refs/heads/A "$ATIP" &&
+	git update-ref refs/heads/B "$BTIP" &&
 	git symbolic-ref HEAD refs/heads/B
 '
 
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index ae5a530..e402aee 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -63,7 +63,7 @@
 	git commit -a -m "updated by origin" &&
 	cd two &&
 	git fetch &&
-	test -f .git/refs/heads/one &&
+	git rev-parse --verify refs/heads/one &&
 	mine=$(git rev-parse refs/heads/one) &&
 	his=$(cd ../one && git rev-parse refs/heads/master) &&
 	test "z$mine" = "z$his"
@@ -73,8 +73,8 @@
 	cd "$D" &&
 	cd three &&
 	git fetch &&
-	test -f .git/refs/heads/two &&
-	test -f .git/refs/heads/one &&
+	git rev-parse --verify refs/heads/two &&
+	git rev-parse --verify refs/heads/one &&
 	master_in_two=$(cd ../two && git rev-parse master) &&
 	one_in_two=$(cd ../two && git rev-parse one) &&
 	{
diff --git a/t/t5512-ls-remote.sh b/t/t5512-ls-remote.sh
index 02106c9..6a94948 100755
--- a/t/t5512-ls-remote.sh
+++ b/t/t5512-ls-remote.sh
@@ -10,6 +10,9 @@
 	test_tick &&
 	git commit -m initial &&
 	git tag mark &&
+	git tag mark1.1 &&
+	git tag mark1.2 &&
+	git tag mark1.10 &&
 	git show-ref --tags -d | sed -e "s/ /	/" >expected.tag &&
 	(
 		echo "$(git rev-parse HEAD)	HEAD"
@@ -39,6 +42,39 @@
 	test_cmp expected.all actual
 '
 
+test_expect_success 'ls-remote --sort="version:refname" --tags self' '
+	cat >expect <<-EOF &&
+	$(git rev-parse mark)	refs/tags/mark
+	$(git rev-parse mark1.1)	refs/tags/mark1.1
+	$(git rev-parse mark1.2)	refs/tags/mark1.2
+	$(git rev-parse mark1.10)	refs/tags/mark1.10
+	EOF
+	git ls-remote --sort="version:refname" --tags self >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'ls-remote --sort="-version:refname" --tags self' '
+	cat >expect <<-EOF &&
+	$(git rev-parse mark1.10)	refs/tags/mark1.10
+	$(git rev-parse mark1.2)	refs/tags/mark1.2
+	$(git rev-parse mark1.1)	refs/tags/mark1.1
+	$(git rev-parse mark)	refs/tags/mark
+	EOF
+	git ls-remote --sort="-version:refname" --tags self >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'ls-remote --sort="-refname" --tags self' '
+	cat >expect <<-EOF &&
+	$(git rev-parse mark1.2)	refs/tags/mark1.2
+	$(git rev-parse mark1.10)	refs/tags/mark1.10
+	$(git rev-parse mark1.1)	refs/tags/mark1.1
+	$(git rev-parse mark)	refs/tags/mark
+	EOF
+	git ls-remote --sort="-refname" --tags self >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'dies when no remote specified and no default remotes found' '
 	test_must_fail git ls-remote
 '
@@ -131,7 +167,7 @@
 
 test_expect_success 'Report match with --exit-code' '
 	git ls-remote --exit-code other.git "refs/tags/*" >actual &&
-	git ls-remote . tags/mark >expect &&
+	git ls-remote . tags/mark* >expect &&
 	test_cmp expect actual
 '
 
@@ -171,13 +207,17 @@
 '
 
 test_expect_success 'ls-remote --symref' '
-	cat >expect <<-\EOF &&
+	git fetch origin &&
+	cat >expect <<-EOF &&
 	ref: refs/heads/master	HEAD
-	1bd44cb9d13204b0fe1958db0082f5028a16eb3a	HEAD
-	1bd44cb9d13204b0fe1958db0082f5028a16eb3a	refs/heads/master
-	1bd44cb9d13204b0fe1958db0082f5028a16eb3a	refs/remotes/origin/HEAD
-	1bd44cb9d13204b0fe1958db0082f5028a16eb3a	refs/remotes/origin/master
-	1bd44cb9d13204b0fe1958db0082f5028a16eb3a	refs/tags/mark
+	$(git rev-parse HEAD)	HEAD
+	$(git rev-parse refs/heads/master)	refs/heads/master
+	$(git rev-parse HEAD)	refs/remotes/origin/HEAD
+	$(git rev-parse refs/remotes/origin/master)	refs/remotes/origin/master
+	$(git rev-parse refs/tags/mark)	refs/tags/mark
+	$(git rev-parse refs/tags/mark1.1)	refs/tags/mark1.1
+	$(git rev-parse refs/tags/mark1.10)	refs/tags/mark1.10
+	$(git rev-parse refs/tags/mark1.2)	refs/tags/mark1.2
 	EOF
 	git ls-remote --symref >actual &&
 	test_cmp expect actual
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 8223913..a5077d8 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -94,6 +94,9 @@
 }
 
 check_push_result () {
+	test $# -ge 3 ||
+	error "bug in the test script: check_push_result requires at least 3 parameters"
+
 	repo_name="$1"
 	shift
 
@@ -553,10 +556,7 @@
 test_expect_success 'push with dry-run' '
 
 	mk_test testrepo heads/master &&
-	(
-		cd testrepo &&
-		old_commit=$(git show-ref -s --verify refs/heads/master)
-	) &&
+	old_commit=$(git -C testrepo show-ref -s --verify refs/heads/master) &&
 	git push --dry-run testrepo : &&
 	check_push_result testrepo $old_commit heads/master
 '
@@ -612,7 +612,7 @@
 	chmod +x testrepo/.git/hooks/pre-receive &&
 	(
 		cd child &&
-		git pull .. master
+		git pull .. master &&
 		test_must_fail git push &&
 		test $(git rev-parse master) != \
 			$(git rev-parse remotes/origin/master)
@@ -634,7 +634,7 @@
 	orgmaster=$(cd testrepo && git show-ref -s --verify refs/heads/master) &&
 	newmaster=$(git show-ref -s --verify refs/heads/master) &&
 	orgnext=$(cd testrepo && git show-ref -s --verify refs/heads/next) &&
-	newnext=$_z40 &&
+	newnext=$ZERO_OID &&
 	git push testrepo refs/heads/master:refs/heads/master :refs/heads/next &&
 	(
 		cd testrepo/.git &&
@@ -672,15 +672,15 @@
 	(
 		cd testrepo/.git &&
 		cat >pre-receive.expect <<-EOF &&
-		$_z40 $_z40 refs/heads/master
+		$ZERO_OID $ZERO_OID refs/heads/master
 		EOF
 
 		cat >update.expect <<-EOF &&
-		refs/heads/master $_z40 $_z40
+		refs/heads/master $ZERO_OID $ZERO_OID
 		EOF
 
 		cat >post-receive.expect <<-EOF &&
-		$_z40 $_z40 refs/heads/master
+		$ZERO_OID $ZERO_OID refs/heads/master
 		EOF
 
 		cat >post-update.expect <<-EOF &&
@@ -703,12 +703,12 @@
 		cd testrepo/.git &&
 		cat >pre-receive.expect <<-EOF &&
 		$orgmaster $newmaster refs/heads/master
-		$_z40 $_z40 refs/heads/nonexistent
+		$ZERO_OID $ZERO_OID refs/heads/nonexistent
 		EOF
 
 		cat >update.expect <<-EOF &&
 		refs/heads/master $orgmaster $newmaster
-		refs/heads/nonexistent $_z40 $_z40
+		refs/heads/nonexistent $ZERO_OID $ZERO_OID
 		EOF
 
 		cat >post-receive.expect <<-EOF &&
@@ -732,11 +732,11 @@
 	(
 		cd testrepo/.git &&
 		cat >pre-receive.expect <<-EOF &&
-		$_z40 $_z40 refs/heads/nonexistent
+		$ZERO_OID $ZERO_OID refs/heads/nonexistent
 		EOF
 
 		cat >update.expect <<-EOF &&
-		refs/heads/nonexistent $_z40 $_z40
+		refs/heads/nonexistent $ZERO_OID $ZERO_OID
 		EOF
 
 		test_cmp pre-receive.expect pre-receive.actual &&
@@ -751,7 +751,7 @@
 	orgmaster=$(cd testrepo && git show-ref -s --verify refs/heads/master) &&
 	newmaster=$(git show-ref -s --verify refs/heads/master) &&
 	orgnext=$(cd testrepo && git show-ref -s --verify refs/heads/next) &&
-	newnext=$_z40 &&
+	newnext=$ZERO_OID &&
 	orgpu=$(cd testrepo && git show-ref -s --verify refs/heads/pu) &&
 	newpu=$(git show-ref -s --verify refs/heads/master) &&
 	git push testrepo refs/heads/master:refs/heads/master \
@@ -763,14 +763,14 @@
 		$orgmaster $newmaster refs/heads/master
 		$orgnext $newnext refs/heads/next
 		$orgpu $newpu refs/heads/pu
-		$_z40 $_z40 refs/heads/nonexistent
+		$ZERO_OID $ZERO_OID refs/heads/nonexistent
 		EOF
 
 		cat >update.expect <<-EOF &&
 		refs/heads/master $orgmaster $newmaster
 		refs/heads/next $orgnext $newnext
 		refs/heads/pu $orgpu $newpu
-		refs/heads/nonexistent $_z40 $_z40
+		refs/heads/nonexistent $ZERO_OID $ZERO_OID
 		EOF
 
 		cat >post-receive.expect <<-EOF &&
@@ -1121,6 +1121,25 @@
 	)
 '
 
+test_expect_success 'fetch exact SHA1 in protocol v2' '
+	mk_test testrepo heads/master hidden/one &&
+	git push testrepo master:refs/hidden/one &&
+	git -C testrepo config transfer.hiderefs refs/hidden &&
+	check_push_result testrepo $the_commit hidden/one &&
+
+	mk_child testrepo child &&
+	git -C child config protocol.version 2 &&
+
+	# make sure $the_commit does not exist here
+	git -C child repack -a -d &&
+	git -C child prune &&
+	test_must_fail git -C child cat-file -t $the_commit &&
+
+	# fetching the hidden object succeeds by default
+	# NEEDSWORK: should this match the v0 behavior instead?
+	git -C child fetch -v ../testrepo $the_commit:refs/heads/copy
+'
+
 for configallowtipsha1inwant in true false
 do
 	test_expect_success "shallow fetch reachable SHA1 (but not a ref), allowtipsha1inwant=$configallowtipsha1inwant" '
diff --git a/t/t5527-fetch-odd-refs.sh b/t/t5527-fetch-odd-refs.sh
index 207899a..3b0cb98 100755
--- a/t/t5527-fetch-odd-refs.sh
+++ b/t/t5527-fetch-odd-refs.sh
@@ -27,7 +27,7 @@
 '
 
 test_expect_success 'try to create repo with absurdly long refname' '
-	ref240=$_z40/$_z40/$_z40/$_z40/$_z40/$_z40 &&
+	ref240=$ZERO_OID/$ZERO_OID/$ZERO_OID/$ZERO_OID/$ZERO_OID/$ZERO_OID &&
 	ref1440=$ref240/$ref240/$ref240/$ref240/$ref240/$ref240 &&
 	git init long &&
 	(
diff --git a/t/t5541-http-push-smart.sh b/t/t5541-http-push-smart.sh
index 21340e8..a2af693 100755
--- a/t/t5541-http-push-smart.sh
+++ b/t/t5541-http-push-smart.sh
@@ -377,5 +377,17 @@
 	grep "^To $HTTPD_URL/smart/test_repo.git" status
 '
 
+test_expect_success 'colorize errors/hints' '
+	cd "$ROOT_PATH"/test_repo_clone &&
+	test_must_fail git -c color.transport=always -c color.advice=always \
+		-c color.push=always \
+		push origin origin/master^:master 2>act &&
+	test_decode_color <act >decoded &&
+	test_i18ngrep "<RED>.*rejected.*<RESET>" decoded &&
+	test_i18ngrep "<RED>error: failed to push some refs" decoded &&
+	test_i18ngrep "<YELLOW>hint: " decoded &&
+	test_i18ngrep ! "^hint: " decoded
+'
+
 stop_httpd
 test_done
diff --git a/t/t5550-http-fetch-dumb.sh b/t/t5550-http-fetch-dumb.sh
index 8552184..6d7d88c 100755
--- a/t/t5550-http-fetch-dumb.sh
+++ b/t/t5550-http-fetch-dumb.sh
@@ -169,6 +169,17 @@
 	test_cmp file clone2/file
 '
 
+test_expect_success 'manual http-fetch without -a works just as well' '
+	cp -R clone-tmpl clone3 &&
+
+	HEAD=$(git rev-parse --verify HEAD) &&
+	(cd clone3 &&
+	 git http-fetch -w heads/master-new $HEAD $(git config remote.origin.url) &&
+	 git checkout master-new &&
+	 test $HEAD = $(git rev-parse --verify HEAD)) &&
+	test_cmp file clone3/file
+'
+
 test_expect_success 'http remote detects correct HEAD' '
 	git push public master:other &&
 	(cd clone &&
diff --git a/t/t5551-http-fetch-smart.sh b/t/t5551-http-fetch-smart.sh
index f5721b4..913089b 100755
--- a/t/t5551-http-fetch-smart.sh
+++ b/t/t5551-http-fetch-smart.sh
@@ -26,14 +26,14 @@
 cat >exp <<EOF
 > GET /smart/repo.git/info/refs?service=git-upload-pack HTTP/1.1
 > Accept: */*
-> Accept-Encoding: gzip
+> Accept-Encoding: ENCODINGS
 > Pragma: no-cache
 < HTTP/1.1 200 OK
 < Pragma: no-cache
 < Cache-Control: no-cache, max-age=0, must-revalidate
 < Content-Type: application/x-git-upload-pack-advertisement
 > POST /smart/repo.git/git-upload-pack HTTP/1.1
-> Accept-Encoding: gzip
+> Accept-Encoding: ENCODINGS
 > Content-Type: application/x-git-upload-pack-request
 > Accept: application/x-git-upload-pack-result
 > Content-Length: xxx
@@ -79,8 +79,13 @@
 		/^< Date: /d
 		/^< Content-Length: /d
 		/^< Transfer-Encoding: /d
-	" >act &&
-	test_cmp exp act
+	" >actual &&
+	sed -e "s/^> Accept-Encoding: .*/> Accept-Encoding: ENCODINGS/" \
+			actual >actual.smudged &&
+	test_cmp exp actual.smudged &&
+
+	grep "Accept-Encoding:.*gzip" actual >actual.gzip &&
+	test_line_count = 2 actual.gzip
 '
 
 test_expect_success 'fetch changes via http' '
diff --git a/t/t5571-pre-push-hook.sh b/t/t5571-pre-push-hook.sh
index ba975bb..ac53d63 100755
--- a/t/t5571-pre-push-hook.sh
+++ b/t/t5571-pre-push-hook.sh
@@ -78,8 +78,8 @@
 cat >expected <<EOF
 parent1
 repo1
-refs/tags/one $COMMIT1 refs/tags/tag1 $_z40
-HEAD~ $COMMIT2 refs/heads/prev $_z40
+refs/tags/one $COMMIT1 refs/tags/tag1 $ZERO_OID
+HEAD~ $COMMIT2 refs/heads/prev $ZERO_OID
 EOF
 
 test_expect_success 'push non-branches' '
@@ -90,7 +90,7 @@
 cat >expected <<EOF
 parent1
 repo1
-(delete) $_z40 refs/heads/prev $COMMIT2
+(delete) $ZERO_OID refs/heads/prev $COMMIT2
 EOF
 
 test_expect_success 'push delete' '
@@ -101,7 +101,7 @@
 cat >expected <<EOF
 repo1
 repo1
-HEAD $COMMIT3 refs/heads/other $_z40
+HEAD $COMMIT3 refs/heads/other $ZERO_OID
 EOF
 
 test_expect_success 'push to URL' '
diff --git a/t/t5572-pull-submodule.sh b/t/t5572-pull-submodule.sh
index 321bd37..f916729 100755
--- a/t/t5572-pull-submodule.sh
+++ b/t/t5572-pull-submodule.sh
@@ -132,4 +132,25 @@
 	test_i18ngrep "locally recorded submodule modifications" err
 '
 
+test_expect_success 'branch has no merge base with remote-tracking counterpart' '
+	rm -rf parent child &&
+
+	test_create_repo a-submodule &&
+	test_commit -C a-submodule foo &&
+
+	test_create_repo parent &&
+	git -C parent submodule add "$(pwd)/a-submodule" &&
+	git -C parent commit -m foo &&
+
+	git clone parent child &&
+
+	# Reset master so that it has no merge base with
+	# refs/remotes/origin/master.
+	OTHER=$(git -C child commit-tree -m bar \
+		$(git -C child rev-parse HEAD^{tree})) &&
+	git -C child reset --hard "$OTHER" &&
+
+	git -C child pull --recurse-submodules --rebase
+'
+
 test_done
diff --git a/t/t5701-git-serve.sh b/t/t5701-git-serve.sh
new file mode 100755
index 0000000..75ec79e
--- /dev/null
+++ b/t/t5701-git-serve.sh
@@ -0,0 +1,211 @@
+#!/bin/sh
+
+test_description='test git-serve and server commands'
+
+. ./test-lib.sh
+
+test_expect_success 'test capability advertisement' '
+	cat >expect <<-EOF &&
+	version 2
+	agent=git/$(git version | cut -d" " -f3)
+	ls-refs
+	fetch=shallow
+	server-option
+	0000
+	EOF
+
+	git serve --advertise-capabilities >out &&
+	test-pkt-line unpack <out >actual &&
+	test_cmp actual expect
+'
+
+test_expect_success 'stateless-rpc flag does not list capabilities' '
+	# Empty request
+	test-pkt-line pack >in <<-EOF &&
+	0000
+	EOF
+	git serve --stateless-rpc >out <in &&
+	test_must_be_empty out &&
+
+	# EOF
+	git serve --stateless-rpc >out &&
+	test_must_be_empty out
+'
+
+test_expect_success 'request invalid capability' '
+	test-pkt-line pack >in <<-EOF &&
+	foobar
+	0000
+	EOF
+	test_must_fail git serve --stateless-rpc 2>err <in &&
+	test_i18ngrep "unknown capability" err
+'
+
+test_expect_success 'request with no command' '
+	test-pkt-line pack >in <<-EOF &&
+	agent=git/test
+	0000
+	EOF
+	test_must_fail git serve --stateless-rpc 2>err <in &&
+	test_i18ngrep "no command requested" err
+'
+
+test_expect_success 'request invalid command' '
+	test-pkt-line pack >in <<-EOF &&
+	command=foo
+	agent=git/test
+	0000
+	EOF
+	test_must_fail git serve --stateless-rpc 2>err <in &&
+	test_i18ngrep "invalid command" err
+'
+
+# Test the basics of ls-refs
+#
+test_expect_success 'setup some refs and tags' '
+	test_commit one &&
+	git branch dev master &&
+	test_commit two &&
+	git symbolic-ref refs/heads/release refs/heads/master &&
+	git tag -a -m "annotated tag" annotated-tag
+'
+
+test_expect_success 'basics of ls-refs' '
+	test-pkt-line pack >in <<-EOF &&
+	command=ls-refs
+	0000
+	EOF
+
+	cat >expect <<-EOF &&
+	$(git rev-parse HEAD) HEAD
+	$(git rev-parse refs/heads/dev) refs/heads/dev
+	$(git rev-parse refs/heads/master) refs/heads/master
+	$(git rev-parse refs/heads/release) refs/heads/release
+	$(git rev-parse refs/tags/annotated-tag) refs/tags/annotated-tag
+	$(git rev-parse refs/tags/one) refs/tags/one
+	$(git rev-parse refs/tags/two) refs/tags/two
+	0000
+	EOF
+
+	git serve --stateless-rpc <in >out &&
+	test-pkt-line unpack <out >actual &&
+	test_cmp actual expect
+'
+
+test_expect_success 'basic ref-prefixes' '
+	test-pkt-line pack >in <<-EOF &&
+	command=ls-refs
+	0001
+	ref-prefix refs/heads/master
+	ref-prefix refs/tags/one
+	0000
+	EOF
+
+	cat >expect <<-EOF &&
+	$(git rev-parse refs/heads/master) refs/heads/master
+	$(git rev-parse refs/tags/one) refs/tags/one
+	0000
+	EOF
+
+	git serve --stateless-rpc <in >out &&
+	test-pkt-line unpack <out >actual &&
+	test_cmp actual expect
+'
+
+test_expect_success 'refs/heads prefix' '
+	test-pkt-line pack >in <<-EOF &&
+	command=ls-refs
+	0001
+	ref-prefix refs/heads/
+	0000
+	EOF
+
+	cat >expect <<-EOF &&
+	$(git rev-parse refs/heads/dev) refs/heads/dev
+	$(git rev-parse refs/heads/master) refs/heads/master
+	$(git rev-parse refs/heads/release) refs/heads/release
+	0000
+	EOF
+
+	git serve --stateless-rpc <in >out &&
+	test-pkt-line unpack <out >actual &&
+	test_cmp actual expect
+'
+
+test_expect_success 'peel parameter' '
+	test-pkt-line pack >in <<-EOF &&
+	command=ls-refs
+	0001
+	peel
+	ref-prefix refs/tags/
+	0000
+	EOF
+
+	cat >expect <<-EOF &&
+	$(git rev-parse refs/tags/annotated-tag) refs/tags/annotated-tag peeled:$(git rev-parse refs/tags/annotated-tag^{})
+	$(git rev-parse refs/tags/one) refs/tags/one
+	$(git rev-parse refs/tags/two) refs/tags/two
+	0000
+	EOF
+
+	git serve --stateless-rpc <in >out &&
+	test-pkt-line unpack <out >actual &&
+	test_cmp actual expect
+'
+
+test_expect_success 'symrefs parameter' '
+	test-pkt-line pack >in <<-EOF &&
+	command=ls-refs
+	0001
+	symrefs
+	ref-prefix refs/heads/
+	0000
+	EOF
+
+	cat >expect <<-EOF &&
+	$(git rev-parse refs/heads/dev) refs/heads/dev
+	$(git rev-parse refs/heads/master) refs/heads/master
+	$(git rev-parse refs/heads/release) refs/heads/release symref-target:refs/heads/master
+	0000
+	EOF
+
+	git serve --stateless-rpc <in >out &&
+	test-pkt-line unpack <out >actual &&
+	test_cmp actual expect
+'
+
+test_expect_success 'sending server-options' '
+	test-pkt-line pack >in <<-EOF &&
+	command=ls-refs
+	server-option=hello
+	server-option=world
+	0001
+	ref-prefix HEAD
+	0000
+	EOF
+
+	cat >expect <<-EOF &&
+	$(git rev-parse HEAD) HEAD
+	0000
+	EOF
+
+	git serve --stateless-rpc <in >out &&
+	test-pkt-line unpack <out >actual &&
+	test_cmp actual expect
+'
+
+test_expect_success 'unexpected lines are not allowed in fetch request' '
+	git init server &&
+
+	test-pkt-line pack >in <<-EOF &&
+	command=fetch
+	0001
+	this-is-not-a-command
+	0000
+	EOF
+
+	test_must_fail git -C server serve --stateless-rpc <in >/dev/null 2>err &&
+	grep "unexpected line: .this-is-not-a-command." err
+'
+
+test_done
diff --git a/t/t5702-protocol-v2.sh b/t/t5702-protocol-v2.sh
new file mode 100755
index 0000000..a4fe650
--- /dev/null
+++ b/t/t5702-protocol-v2.sh
@@ -0,0 +1,431 @@
+#!/bin/sh
+
+test_description='test git wire-protocol version 2'
+
+TEST_NO_CREATE_REPO=1
+
+. ./test-lib.sh
+
+# Test protocol v2 with 'git://' transport
+#
+. "$TEST_DIRECTORY"/lib-git-daemon.sh
+start_git_daemon --export-all --enable=receive-pack
+daemon_parent=$GIT_DAEMON_DOCUMENT_ROOT_PATH/parent
+
+test_expect_success 'create repo to be served by git-daemon' '
+	git init "$daemon_parent" &&
+	test_commit -C "$daemon_parent" one
+'
+
+test_expect_success 'list refs with git:// using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -c protocol.version=2 \
+		ls-remote --symref "$GIT_DAEMON_URL/parent" >actual &&
+
+	# Client requested to use protocol v2
+	grep "git> .*\\\0\\\0version=2\\\0$" log &&
+	# Server responded using protocol v2
+	grep "git< version 2" log &&
+
+	git ls-remote --symref "$GIT_DAEMON_URL/parent" >expect &&
+	test_cmp actual expect
+'
+
+test_expect_success 'ref advertisment is filtered with ls-remote using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -c protocol.version=2 \
+		ls-remote "$GIT_DAEMON_URL/parent" master >actual &&
+
+	cat >expect <<-EOF &&
+	$(git -C "$daemon_parent" rev-parse refs/heads/master)$(printf "\t")refs/heads/master
+	EOF
+
+	test_cmp actual expect
+'
+
+test_expect_success 'clone with git:// using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -c protocol.version=2 \
+		clone "$GIT_DAEMON_URL/parent" daemon_child &&
+
+	git -C daemon_child log -1 --format=%s >actual &&
+	git -C "$daemon_parent" log -1 --format=%s >expect &&
+	test_cmp expect actual &&
+
+	# Client requested to use protocol v2
+	grep "clone> .*\\\0\\\0version=2\\\0$" log &&
+	# Server responded using protocol v2
+	grep "clone< version 2" log
+'
+
+test_expect_success 'fetch with git:// using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	test_commit -C "$daemon_parent" two &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -C daemon_child -c protocol.version=2 \
+		fetch &&
+
+	git -C daemon_child log -1 --format=%s origin/master >actual &&
+	git -C "$daemon_parent" log -1 --format=%s >expect &&
+	test_cmp expect actual &&
+
+	# Client requested to use protocol v2
+	grep "fetch> .*\\\0\\\0version=2\\\0$" log &&
+	# Server responded using protocol v2
+	grep "fetch< version 2" log
+'
+
+test_expect_success 'pull with git:// using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -C daemon_child -c protocol.version=2 \
+		pull &&
+
+	git -C daemon_child log -1 --format=%s >actual &&
+	git -C "$daemon_parent" log -1 --format=%s >expect &&
+	test_cmp expect actual &&
+
+	# Client requested to use protocol v2
+	grep "fetch> .*\\\0\\\0version=2\\\0$" log &&
+	# Server responded using protocol v2
+	grep "fetch< version 2" log
+'
+
+test_expect_success 'push with git:// and a config of v2 does not request v2' '
+	test_when_finished "rm -f log" &&
+
+	# Till v2 for push is designed, make sure that if a client has
+	# protocol.version configured to use v2, that the client instead falls
+	# back and uses v0.
+
+	test_commit -C daemon_child three &&
+
+	# Push to another branch, as the target repository has the
+	# master branch checked out and we cannot push into it.
+	GIT_TRACE_PACKET="$(pwd)/log" git -C daemon_child -c protocol.version=2 \
+		push origin HEAD:client_branch &&
+
+	git -C daemon_child log -1 --format=%s >actual &&
+	git -C "$daemon_parent" log -1 --format=%s client_branch >expect &&
+	test_cmp expect actual &&
+
+	# Client requested to use protocol v2
+	! grep "push> .*\\\0\\\0version=2\\\0$" log &&
+	# Server responded using protocol v2
+	! grep "push< version 2" log
+'
+
+stop_git_daemon
+
+# Test protocol v2 with 'file://' transport
+#
+test_expect_success 'create repo to be served by file:// transport' '
+	git init file_parent &&
+	test_commit -C file_parent one
+'
+
+test_expect_success 'list refs with file:// using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -c protocol.version=2 \
+		ls-remote --symref "file://$(pwd)/file_parent" >actual &&
+
+	# Server responded using protocol v2
+	grep "git< version 2" log &&
+
+	git ls-remote --symref "file://$(pwd)/file_parent" >expect &&
+	test_cmp actual expect
+'
+
+test_expect_success 'ref advertisment is filtered with ls-remote using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -c protocol.version=2 \
+		ls-remote "file://$(pwd)/file_parent" master >actual &&
+
+	cat >expect <<-EOF &&
+	$(git -C file_parent rev-parse refs/heads/master)$(printf "\t")refs/heads/master
+	EOF
+
+	test_cmp actual expect
+'
+
+test_expect_success 'server-options are sent when using ls-remote' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -c protocol.version=2 \
+		ls-remote -o hello -o world "file://$(pwd)/file_parent" master >actual &&
+
+	cat >expect <<-EOF &&
+	$(git -C file_parent rev-parse refs/heads/master)$(printf "\t")refs/heads/master
+	EOF
+
+	test_cmp actual expect &&
+	grep "server-option=hello" log &&
+	grep "server-option=world" log
+'
+
+
+test_expect_success 'clone with file:// using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -c protocol.version=2 \
+		clone "file://$(pwd)/file_parent" file_child &&
+
+	git -C file_child log -1 --format=%s >actual &&
+	git -C file_parent log -1 --format=%s >expect &&
+	test_cmp expect actual &&
+
+	# Server responded using protocol v2
+	grep "clone< version 2" log
+'
+
+test_expect_success 'fetch with file:// using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	test_commit -C file_parent two &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -C file_child -c protocol.version=2 \
+		fetch origin &&
+
+	git -C file_child log -1 --format=%s origin/master >actual &&
+	git -C file_parent log -1 --format=%s >expect &&
+	test_cmp expect actual &&
+
+	# Server responded using protocol v2
+	grep "fetch< version 2" log
+'
+
+test_expect_success 'ref advertisment is filtered during fetch using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	test_commit -C file_parent three &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -C file_child -c protocol.version=2 \
+		fetch origin master &&
+
+	git -C file_child log -1 --format=%s origin/master >actual &&
+	git -C file_parent log -1 --format=%s >expect &&
+	test_cmp expect actual &&
+
+	! grep "refs/tags/one" log &&
+	! grep "refs/tags/two" log &&
+	! grep "refs/tags/three" log
+'
+
+test_expect_success 'server-options are sent when fetching' '
+	test_when_finished "rm -f log" &&
+
+	test_commit -C file_parent four &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -C file_child -c protocol.version=2 \
+		fetch -o hello -o world origin master &&
+
+	git -C file_child log -1 --format=%s origin/master >actual &&
+	git -C file_parent log -1 --format=%s >expect &&
+	test_cmp expect actual &&
+
+	grep "server-option=hello" log &&
+	grep "server-option=world" log
+'
+
+test_expect_success 'upload-pack respects config using protocol v2' '
+	git init server &&
+	write_script server/.git/hook <<-\EOF &&
+		touch hookout
+		"$@"
+	EOF
+	test_commit -C server one &&
+
+	test_config_global uploadpack.packobjectshook ./hook &&
+	test_path_is_missing server/.git/hookout &&
+	git -c protocol.version=2 clone "file://$(pwd)/server" client &&
+	test_path_is_file server/.git/hookout
+'
+
+test_expect_success 'setup filter tests' '
+	rm -rf server client &&
+	git init server &&
+
+	# 1 commit to create a file, and 1 commit to modify it
+	test_commit -C server message1 a.txt &&
+	test_commit -C server message2 a.txt &&
+	git -C server config protocol.version 2 &&
+	git -C server config uploadpack.allowfilter 1 &&
+	git -C server config uploadpack.allowanysha1inwant 1 &&
+	git -C server config protocol.version 2
+'
+
+test_expect_success 'partial clone' '
+	GIT_TRACE_PACKET="$(pwd)/trace" git -c protocol.version=2 \
+		clone --filter=blob:none "file://$(pwd)/server" client &&
+	grep "version 2" trace &&
+
+	# Ensure that the old version of the file is missing
+	git -C client rev-list master --quiet --objects --missing=print \
+		>observed.oids &&
+	grep "$(git -C server rev-parse message1:a.txt)" observed.oids &&
+
+	# Ensure that client passes fsck
+	git -C client fsck
+'
+
+test_expect_success 'dynamically fetch missing object' '
+	rm "$(pwd)/trace" &&
+	GIT_TRACE_PACKET="$(pwd)/trace" git -C client -c protocol.version=2 \
+		cat-file -p $(git -C server rev-parse message1:a.txt) &&
+	grep "version 2" trace
+'
+
+test_expect_success 'partial fetch' '
+	rm -rf client "$(pwd)/trace" &&
+	git init client &&
+	SERVER="file://$(pwd)/server" &&
+	test_config -C client extensions.partialClone "$SERVER" &&
+
+	GIT_TRACE_PACKET="$(pwd)/trace" git -C client -c protocol.version=2 \
+		fetch --filter=blob:none "$SERVER" master:refs/heads/other &&
+	grep "version 2" trace &&
+
+	# Ensure that the old version of the file is missing
+	git -C client rev-list other --quiet --objects --missing=print \
+		>observed.oids &&
+	grep "$(git -C server rev-parse message1:a.txt)" observed.oids &&
+
+	# Ensure that client passes fsck
+	git -C client fsck
+'
+
+test_expect_success 'do not advertise filter if not configured to do so' '
+	SERVER="file://$(pwd)/server" &&
+
+	rm "$(pwd)/trace" &&
+	git -C server config uploadpack.allowfilter 1 &&
+	GIT_TRACE_PACKET="$(pwd)/trace" git -c protocol.version=2 \
+		ls-remote "$SERVER" &&
+	grep "fetch=.*filter" trace &&
+
+	rm "$(pwd)/trace" &&
+	git -C server config uploadpack.allowfilter 0 &&
+	GIT_TRACE_PACKET="$(pwd)/trace" git -c protocol.version=2 \
+		ls-remote "$SERVER" &&
+	grep "fetch=" trace >fetch_capabilities &&
+	! grep filter fetch_capabilities
+'
+
+test_expect_success 'partial clone warns if filter is not advertised' '
+	rm -rf client &&
+	git -C server config uploadpack.allowfilter 0 &&
+	git -c protocol.version=2 \
+		clone --filter=blob:none "file://$(pwd)/server" client 2>err &&
+	test_i18ngrep "filtering not recognized by server, ignoring" err
+'
+
+test_expect_success 'even with handcrafted request, filter does not work if not advertised' '
+	git -C server config uploadpack.allowfilter 0 &&
+
+	# Custom request that tries to filter even though it is not advertised.
+	test-pkt-line pack >in <<-EOF &&
+	command=fetch
+	0001
+	want $(git -C server rev-parse master)
+	filter blob:none
+	0000
+	EOF
+
+	test_must_fail git -C server serve --stateless-rpc <in >/dev/null 2>err &&
+	grep "unexpected line: .filter blob:none." err &&
+
+	# Exercise to ensure that if advertised, filter works
+	git -C server config uploadpack.allowfilter 1 &&
+	git -C server serve --stateless-rpc <in >/dev/null
+'
+
+test_expect_success 'default refspec is used to filter ref when fetchcing' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -C file_child -c protocol.version=2 \
+		fetch origin &&
+
+	git -C file_child log -1 --format=%s three >actual &&
+	git -C file_parent log -1 --format=%s three >expect &&
+	test_cmp expect actual &&
+
+	grep "ref-prefix refs/heads/" log &&
+	grep "ref-prefix refs/tags/" log
+'
+
+# Test protocol v2 with 'http://' transport
+#
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+test_expect_success 'create repo to be served by http:// transport' '
+	git init "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" config http.receivepack true &&
+	test_commit -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" one
+'
+
+test_expect_success 'clone with http:// using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" GIT_TRACE_CURL="$(pwd)/log" git -c protocol.version=2 \
+		clone "$HTTPD_URL/smart/http_parent" http_child &&
+
+	git -C http_child log -1 --format=%s >actual &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" log -1 --format=%s >expect &&
+	test_cmp expect actual &&
+
+	# Client requested to use protocol v2
+	grep "Git-Protocol: version=2" log &&
+	# Server responded using protocol v2
+	grep "git< version 2" log
+'
+
+test_expect_success 'fetch with http:// using protocol v2' '
+	test_when_finished "rm -f log" &&
+
+	test_commit -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" two &&
+
+	GIT_TRACE_PACKET="$(pwd)/log" git -C http_child -c protocol.version=2 \
+		fetch &&
+
+	git -C http_child log -1 --format=%s origin/master >actual &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" log -1 --format=%s >expect &&
+	test_cmp expect actual &&
+
+	# Server responded using protocol v2
+	grep "git< version 2" log
+'
+
+test_expect_success 'push with http:// and a config of v2 does not request v2' '
+	test_when_finished "rm -f log" &&
+	# Till v2 for push is designed, make sure that if a client has
+	# protocol.version configured to use v2, that the client instead falls
+	# back and uses v0.
+
+	test_commit -C http_child three &&
+
+	# Push to another branch, as the target repository has the
+	# master branch checked out and we cannot push into it.
+	GIT_TRACE_PACKET="$(pwd)/log" git -C http_child -c protocol.version=2 \
+		push origin HEAD:client_branch &&
+
+	git -C http_child log -1 --format=%s >actual &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/http_parent" log -1 --format=%s client_branch >expect &&
+	test_cmp expect actual &&
+
+	# Client didnt request to use protocol v2
+	! grep "Git-Protocol: version=2" log &&
+	# Server didnt respond using protocol v2
+	! grep "git< version 2" log
+'
+
+
+stop_httpd
+
+test_done
diff --git a/t/t6001-rev-list-graft.sh b/t/t6001-rev-list-graft.sh
index 05ddc69..7504ba4 100755
--- a/t/t6001-rev-list-graft.sh
+++ b/t/t6001-rev-list-graft.sh
@@ -110,4 +110,13 @@
 	"
 
 done
+
+test_expect_success 'show advice that grafts are deprecated' '
+	git show HEAD 2>err &&
+	test_i18ngrep "git replace" err &&
+	test_config advice.graftFileDeprecated false &&
+	git show HEAD 2>err &&
+	test_i18ngrep ! "git replace" err
+'
+
 test_done
diff --git a/t/t6006-rev-list-format.sh b/t/t6006-rev-list-format.sh
index 98be78b..ec42c2f 100755
--- a/t/t6006-rev-list-format.sh
+++ b/t/t6006-rev-list-format.sh
@@ -447,8 +447,8 @@
 	git log -1 --format="%h %h %h" HEAD >actual1 &&
 	git log -1 --abbrev=5 --format="%h %h %h" HEAD >actual2 &&
 	git log -1 --abbrev=5 --format="%H %H %H" HEAD >actual3 &&
-	sed -e "s/$_x40/LONG/g" -e "s/$_x05/SHORT/g" <actual2 >fuzzy2 &&
-	sed -e "s/$_x40/LONG/g" -e "s/$_x05/SHORT/g" <actual3 >fuzzy3 &&
+	sed -e "s/$OID_REGEX/LONG/g" -e "s/$_x05/SHORT/g" <actual2 >fuzzy2 &&
+	sed -e "s/$OID_REGEX/LONG/g" -e "s/$_x05/SHORT/g" <actual3 >fuzzy3 &&
 	test_cmp expect2 fuzzy2 &&
 	test_cmp expect3 fuzzy3 &&
 	! test_cmp actual1 actual2
diff --git a/t/t6010-merge-base.sh b/t/t6010-merge-base.sh
index 31db7b5..aa2d360 100755
--- a/t/t6010-merge-base.sh
+++ b/t/t6010-merge-base.sh
@@ -34,7 +34,7 @@
 
 	commit=$(echo $NAME | git commit-tree $T $PARENTS) &&
 
-	echo $commit >.git/refs/tags/$NAME &&
+	git update-ref "refs/tags/$NAME" "$commit" &&
 	echo $commit
 }
 
diff --git a/t/t6012-rev-list-simplify.sh b/t/t6012-rev-list-simplify.sh
index 2a0fbb8..b5a1190 100755
--- a/t/t6012-rev-list-simplify.sh
+++ b/t/t6012-rev-list-simplify.sh
@@ -9,7 +9,7 @@
 }
 
 unnote () {
-	git name-rev --tags --stdin | sed -e "s|$_x40 (tags/\([^)]*\)) |\1 |g"
+	git name-rev --tags --stdin | sed -e "s|$OID_REGEX (tags/\([^)]*\)) |\1 |g"
 }
 
 test_expect_success setup '
diff --git a/t/t6022-merge-rename.sh b/t/t6022-merge-rename.sh
index 48747e7..b760c22 100755
--- a/t/t6022-merge-rename.sh
+++ b/t/t6022-merge-rename.sh
@@ -247,7 +247,7 @@
 	git reset --hard HEAD^ &&
 	git checkout change &&
 	GIT_MERGE_VERBOSITY=3 git merge change+rename >out &&
-	test_i18ngrep "^Skipped B" out
+	test_i18ngrep ! "^Skipped B" out
 '
 
 test_expect_success 'setup for rename + d/f conflicts' '
diff --git a/t/t6043-merge-rename-directories.sh b/t/t6043-merge-rename-directories.sh
new file mode 100755
index 0000000..2e28f29
--- /dev/null
+++ b/t/t6043-merge-rename-directories.sh
@@ -0,0 +1,3998 @@
+#!/bin/sh
+
+test_description="recursive merge with directory renames"
+# includes checking of many corner cases, with a similar methodology to:
+#   t6042: corner cases with renames but not criss-cross merges
+#   t6036: corner cases with both renames and criss-cross merges
+#
+# The setup for all of them, pictorially, is:
+#
+#      A
+#      o
+#     / \
+#  O o   ?
+#     \ /
+#      o
+#      B
+#
+# To help make it easier to follow the flow of tests, they have been
+# divided into sections and each test will start with a quick explanation
+# of what commits O, A, and B contain.
+#
+# Notation:
+#    z/{b,c}   means  files z/b and z/c both exist
+#    x/d_1     means  file x/d exists with content d1.  (Purpose of the
+#                     underscore notation is to differentiate different
+#                     files that might be renamed into each other's paths.)
+
+. ./test-lib.sh
+
+
+###########################################################################
+# SECTION 1: Basic cases we should be able to handle
+###########################################################################
+
+# Testcase 1a, Basic directory rename.
+#   Commit O: z/{b,c}
+#   Commit A: y/{b,c}
+#   Commit B: z/{b,c,d,e/f}
+#   Expected: y/{b,c,d,e/f}
+
+test_expect_success '1a-setup: Simple directory rename detection' '
+	test_create_repo 1a &&
+	(
+		cd 1a &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo d >z/d &&
+		mkdir z/e &&
+		echo f >z/e/f &&
+		git add z/d z/e/f &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '1a-check: Simple directory rename detection' '
+	(
+		cd 1a &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 4 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:y/d HEAD:y/e/f &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    B:z/d    B:z/e/f &&
+		test_cmp expect actual &&
+
+		git hash-object y/d >actual &&
+		git rev-parse B:z/d >expect &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse HEAD:z/d &&
+		test_must_fail git rev-parse HEAD:z/e/f &&
+		test_path_is_missing z/d &&
+		test_path_is_missing z/e/f
+	)
+'
+
+# Testcase 1b, Merge a directory with another
+#   Commit O: z/{b,c},   y/d
+#   Commit A: z/{b,c,e}, y/d
+#   Commit B: y/{b,c,d}
+#   Expected: y/{b,c,d,e}
+
+test_expect_success '1b-setup: Merge a directory with another' '
+	test_create_repo 1b &&
+	(
+		cd 1b &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		mkdir y &&
+		echo d >y/d &&
+		git add z y &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		echo e >z/e &&
+		git add z/e &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv z/b y &&
+		git mv z/c y &&
+		rmdir z &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '1b-check: Merge a directory with another' '
+	(
+		cd 1b &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 4 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:y/d HEAD:y/e &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    O:y/d    A:z/e &&
+		test_cmp expect actual &&
+		test_must_fail git rev-parse HEAD:z/e
+	)
+'
+
+# Testcase 1c, Transitive renaming
+#   (Related to testcases 3a and 6d -- when should a transitive rename apply?)
+#   (Related to testcases 9c and 9d -- can transitivity repeat?)
+#   (Related to testcase 12b -- joint-transitivity?)
+#   Commit O: z/{b,c},   x/d
+#   Commit A: y/{b,c},   x/d
+#   Commit B: z/{b,c,d}
+#   Expected: y/{b,c,d}  (because x/d -> z/d -> y/d)
+
+test_expect_success '1c-setup: Transitive renaming' '
+	test_create_repo 1c &&
+	(
+		cd 1c &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		mkdir x &&
+		echo d >x/d &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/d z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '1c-check: Transitive renaming' '
+	(
+		cd 1c &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:y/d &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    O:x/d &&
+		test_cmp expect actual &&
+		test_must_fail git rev-parse HEAD:x/d &&
+		test_must_fail git rev-parse HEAD:z/d &&
+		test_path_is_missing z/d
+	)
+'
+
+# Testcase 1d, Directory renames (merging two directories into one new one)
+#              cause a rename/rename(2to1) conflict
+#   (Related to testcases 1c and 7b)
+#   Commit O. z/{b,c},        y/{d,e}
+#   Commit A. x/{b,c},        y/{d,e,m,wham_1}
+#   Commit B. z/{b,c,n,wham_2}, x/{d,e}
+#   Expected: x/{b,c,d,e,m,n}, CONFLICT:(y/wham_1 & z/wham_2 -> x/wham)
+#   Note: y/m & z/n should definitely move into x.  By the same token, both
+#         y/wham_1 & z/wham_2 should too...giving us a conflict.
+
+test_expect_success '1d-setup: Directory renames cause a rename/rename(2to1) conflict' '
+	test_create_repo 1d &&
+	(
+		cd 1d &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		mkdir y &&
+		echo d >y/d &&
+		echo e >y/e &&
+		git add z y &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z x &&
+		echo m >y/m &&
+		echo wham1 >y/wham &&
+		git add y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv y x &&
+		echo n >z/n &&
+		echo wham2 >z/wham &&
+		git add z &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '1d-check: Directory renames cause a rename/rename(2to1) conflict' '
+	(
+		cd 1d &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT (rename/rename)" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 8 out &&
+		git ls-files -u >out &&
+		test_line_count = 2 out &&
+		git ls-files -o >out &&
+		test_line_count = 3 out &&
+
+		git rev-parse >actual \
+			:0:x/b :0:x/c :0:x/d :0:x/e :0:x/m :0:x/n &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  O:y/d  O:y/e  A:y/m  B:z/n &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse :0:x/wham &&
+		git rev-parse >actual \
+			:2:x/wham :3:x/wham &&
+		git rev-parse >expect \
+			 A:y/wham  B:z/wham &&
+		test_cmp expect actual &&
+
+		test_path_is_missing x/wham &&
+		test_path_is_file x/wham~HEAD &&
+		test_path_is_file x/wham~B^0 &&
+
+		git hash-object >actual \
+			x/wham~HEAD x/wham~B^0 &&
+		git rev-parse >expect \
+			A:y/wham    B:z/wham &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 1e, Renamed directory, with all filenames being renamed too
+#   (Related to testcases 9f & 9g)
+#   Commit O: z/{oldb,oldc}
+#   Commit A: y/{newb,newc}
+#   Commit B: z/{oldb,oldc,d}
+#   Expected: y/{newb,newc,d}
+
+test_expect_success '1e-setup: Renamed directory, with all files being renamed too' '
+	test_create_repo 1e &&
+	(
+		cd 1e &&
+
+		mkdir z &&
+		echo b >z/oldb &&
+		echo c >z/oldc &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		mkdir y &&
+		git mv z/oldb y/newb &&
+		git mv z/oldc y/newc &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo d >z/d &&
+		git add z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '1e-check: Renamed directory, with all files being renamed too' '
+	(
+		cd 1e &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+
+		git rev-parse >actual \
+			HEAD:y/newb HEAD:y/newc HEAD:y/d &&
+		git rev-parse >expect \
+			O:z/oldb    O:z/oldc    B:z/d &&
+		test_cmp expect actual &&
+		test_must_fail git rev-parse HEAD:z/d
+	)
+'
+
+# Testcase 1f, Split a directory into two other directories
+#   (Related to testcases 3a, all of section 2, and all of section 4)
+#   Commit O: z/{b,c,d,e,f}
+#   Commit A: z/{b,c,d,e,f,g}
+#   Commit B: y/{b,c}, x/{d,e,f}
+#   Expected: y/{b,c}, x/{d,e,f,g}
+
+test_expect_success '1f-setup: Split a directory into two other directories' '
+	test_create_repo 1f &&
+	(
+		cd 1f &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		echo d >z/d &&
+		echo e >z/e &&
+		echo f >z/f &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		echo g >z/g &&
+		git add z/g &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		mkdir y &&
+		mkdir x &&
+		git mv z/b y/ &&
+		git mv z/c y/ &&
+		git mv z/d x/ &&
+		git mv z/e x/ &&
+		git mv z/f x/ &&
+		rmdir z &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '1f-check: Split a directory into two other directories' '
+	(
+		cd 1f &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 6 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:x/d HEAD:x/e HEAD:x/f HEAD:x/g &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    O:z/d    O:z/e    O:z/f    A:z/g &&
+		test_cmp expect actual &&
+		test_path_is_missing z/g &&
+		test_must_fail git rev-parse HEAD:z/g
+	)
+'
+
+###########################################################################
+# Rules suggested by testcases in section 1:
+#
+#   We should still detect the directory rename even if it wasn't just
+#   the directory renamed, but the files within it. (see 1b)
+#
+#   If renames split a directory into two or more others, the directory
+#   with the most renames, "wins" (see 1c).  However, see the testcases
+#   in section 2, plus testcases 3a and 4a.
+###########################################################################
+
+
+###########################################################################
+# SECTION 2: Split into multiple directories, with equal number of paths
+#
+# Explore the splitting-a-directory rules a bit; what happens in the
+# edge cases?
+#
+# Note that there is a closely related case of a directory not being
+# split on either side of history, but being renamed differently on
+# each side.  See testcase 8e for that.
+###########################################################################
+
+# Testcase 2a, Directory split into two on one side, with equal numbers of paths
+#   Commit O: z/{b,c}
+#   Commit A: y/b, w/c
+#   Commit B: z/{b,c,d}
+#   Expected: y/b, w/c, z/d, with warning about z/ -> (y/ vs. w/) conflict
+test_expect_success '2a-setup: Directory split into two on one side, with equal numbers of paths' '
+	test_create_repo 2a &&
+	(
+		cd 2a &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		mkdir y &&
+		mkdir w &&
+		git mv z/b y/ &&
+		git mv z/c w/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo d >z/d &&
+		git add z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '2a-check: Directory split into two on one side, with equal numbers of paths' '
+	(
+		cd 2a &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT.*directory rename split" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			:0:y/b :0:w/c :0:z/d &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  B:z/d &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 2b, Directory split into two on one side, with equal numbers of paths
+#   Commit O: z/{b,c}
+#   Commit A: y/b, w/c
+#   Commit B: z/{b,c}, x/d
+#   Expected: y/b, w/c, x/d; No warning about z/ -> (y/ vs. w/) conflict
+test_expect_success '2b-setup: Directory split into two on one side, with equal numbers of paths' '
+	test_create_repo 2b &&
+	(
+		cd 2b &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		mkdir y &&
+		mkdir w &&
+		git mv z/b y/ &&
+		git mv z/c w/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		mkdir x &&
+		echo d >x/d &&
+		git add x/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '2b-check: Directory split into two on one side, with equal numbers of paths' '
+	(
+		cd 2b &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 >out &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			:0:y/b :0:w/c :0:x/d &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  B:x/d &&
+		test_cmp expect actual &&
+		test_i18ngrep ! "CONFLICT.*directory rename split" out
+	)
+'
+
+###########################################################################
+# Rules suggested by section 2:
+#
+#   None; the rule was already covered in section 1.  These testcases are
+#   here just to make sure the conflict resolution and necessary warning
+#   messages are handled correctly.
+###########################################################################
+
+
+###########################################################################
+# SECTION 3: Path in question is the source path for some rename already
+#
+# Combining cases from Section 1 and trying to handle them could lead to
+# directory renaming detection being over-applied.  So, this section
+# provides some good testcases to check that the implementation doesn't go
+# too far.
+###########################################################################
+
+# Testcase 3a, Avoid implicit rename if involved as source on other side
+#   (Related to testcases 1c, 1f, and 9h)
+#   Commit O: z/{b,c,d}
+#   Commit A: z/{b,c,d} (no change)
+#   Commit B: y/{b,c}, x/d
+#   Expected: y/{b,c}, x/d
+test_expect_success '3a-setup: Avoid implicit rename if involved as source on other side' '
+	test_create_repo 3a &&
+	(
+		cd 3a &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		echo d >z/d &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_tick &&
+		git commit --allow-empty -m "A" &&
+
+		git checkout B &&
+		mkdir y &&
+		mkdir x &&
+		git mv z/b y/ &&
+		git mv z/c y/ &&
+		git mv z/d x/ &&
+		rmdir z &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '3a-check: Avoid implicit rename if involved as source on other side' '
+	(
+		cd 3a &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:x/d &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    O:z/d &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 3b, Avoid implicit rename if involved as source on other side
+#   (Related to testcases 5c and 7c, also kind of 1e and 1f)
+#   Commit O: z/{b,c,d}
+#   Commit A: y/{b,c}, x/d
+#   Commit B: z/{b,c}, w/d
+#   Expected: y/{b,c}, CONFLICT:(z/d -> x/d vs. w/d)
+#   NOTE: We're particularly checking that since z/d is already involved as
+#         a source in a file rename on the same side of history, that we don't
+#         get it involved in directory rename detection.  If it were, we might
+#         end up with CONFLICT:(z/d -> y/d vs. x/d vs. w/d), i.e. a
+#         rename/rename/rename(1to3) conflict, which is just weird.
+test_expect_success '3b-setup: Avoid implicit rename if involved as source on current side' '
+	test_create_repo 3b &&
+	(
+		cd 3b &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		echo d >z/d &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		mkdir y &&
+		mkdir x &&
+		git mv z/b y/ &&
+		git mv z/c y/ &&
+		git mv z/d x/ &&
+		rmdir z &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		mkdir w &&
+		git mv z/d w/ &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '3b-check: Avoid implicit rename if involved as source on current side' '
+	(
+		cd 3b &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep CONFLICT.*rename/rename.*z/d.*x/d.*w/d out &&
+		test_i18ngrep ! CONFLICT.*rename/rename.*y/d out &&
+
+		git ls-files -s >out &&
+		test_line_count = 5 out &&
+		git ls-files -u >out &&
+		test_line_count = 3 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			:0:y/b :0:y/c :1:z/d :2:x/d :3:w/d &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  O:z/d  O:z/d  O:z/d &&
+		test_cmp expect actual &&
+
+		test_path_is_missing z/d &&
+		git hash-object >actual \
+			x/d   w/d &&
+		git rev-parse >expect \
+			O:z/d O:z/d &&
+		test_cmp expect actual
+	)
+'
+
+###########################################################################
+# Rules suggested by section 3:
+#
+#   Avoid directory-rename-detection for a path, if that path is the source
+#   of a rename on either side of a merge.
+###########################################################################
+
+
+###########################################################################
+# SECTION 4: Partially renamed directory; still exists on both sides of merge
+#
+# What if we were to attempt to do directory rename detection when someone
+# "mostly" moved a directory but still left some files around, or,
+# equivalently, fully renamed a directory in one commmit and then recreated
+# that directory in a later commit adding some new files and then tried to
+# merge?
+#
+# It's hard to divine user intent in these cases, because you can make an
+# argument that, depending on the intermediate history of the side being
+# merged, that some users will want files in that directory to
+# automatically be detected and renamed, while users with a different
+# intermediate history wouldn't want that rename to happen.
+#
+# I think that it is best to simply not have directory rename detection
+# apply to such cases.  My reasoning for this is four-fold: (1) it's
+# easiest for users in general to figure out what happened if we don't
+# apply directory rename detection in any such case, (2) it's an easy rule
+# to explain ["We don't do directory rename detection if the directory
+# still exists on both sides of the merge"], (3) we can get some hairy
+# edge/corner cases that would be really confusing and possibly not even
+# representable in the index if we were to even try, and [related to 3] (4)
+# attempting to resolve this issue of divining user intent by examining
+# intermediate history goes against the spirit of three-way merges and is a
+# path towards crazy corner cases that are far more complex than what we're
+# already dealing with.
+#
+# Note that the wording of the rule ("We don't do directory rename
+# detection if the directory still exists on both sides of the merge.")
+# also excludes "renaming" of a directory into a subdirectory of itself
+# (e.g. /some/dir/* -> /some/dir/subdir/*).  It may be possible to carve
+# out an exception for "renaming"-beneath-itself cases without opening
+# weird edge/corner cases for other partial directory renames, but for now
+# we are keeping the rule simple.
+#
+# This section contains a test for a partially-renamed-directory case.
+###########################################################################
+
+# Testcase 4a, Directory split, with original directory still present
+#   (Related to testcase 1f)
+#   Commit O: z/{b,c,d,e}
+#   Commit A: y/{b,c,d}, z/e
+#   Commit B: z/{b,c,d,e,f}
+#   Expected: y/{b,c,d}, z/{e,f}
+#   NOTE: Even though most files from z moved to y, we don't want f to follow.
+
+test_expect_success '4a-setup: Directory split, with original directory still present' '
+	test_create_repo 4a &&
+	(
+		cd 4a &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		echo d >z/d &&
+		echo e >z/e &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		mkdir y &&
+		git mv z/b y/ &&
+		git mv z/c y/ &&
+		git mv z/d y/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo f >z/f &&
+		git add z/f &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '4a-check: Directory split, with original directory still present' '
+	(
+		cd 4a &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 5 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:y/d HEAD:z/e HEAD:z/f &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    O:z/d    O:z/e    B:z/f &&
+		test_cmp expect actual
+	)
+'
+
+###########################################################################
+# Rules suggested by section 4:
+#
+#   Directory-rename-detection should be turned off for any directories (as
+#   a source for renames) that exist on both sides of the merge.  (The "as
+#   a source for renames" clarification is due to cases like 1c where
+#   the target directory exists on both sides and we do want the rename
+#   detection.)  But, sadly, see testcase 8b.
+###########################################################################
+
+
+###########################################################################
+# SECTION 5: Files/directories in the way of subset of to-be-renamed paths
+#
+# Implicitly renaming files due to a detected directory rename could run
+# into problems if there are files or directories in the way of the paths
+# we want to rename.  Explore such cases in this section.
+###########################################################################
+
+# Testcase 5a, Merge directories, other side adds files to original and target
+#   Commit O: z/{b,c},       y/d
+#   Commit A: z/{b,c,e_1,f}, y/{d,e_2}
+#   Commit B: y/{b,c,d}
+#   Expected: z/e_1, y/{b,c,d,e_2,f} + CONFLICT warning
+#   NOTE: While directory rename detection is active here causing z/f to
+#         become y/f, we did not apply this for z/e_1 because that would
+#         give us an add/add conflict for y/e_1 vs y/e_2.  This problem with
+#         this add/add, is that both versions of y/e are from the same side
+#         of history, giving us no way to represent this conflict in the
+#         index.
+
+test_expect_success '5a-setup: Merge directories, other side adds files to original and target' '
+	test_create_repo 5a &&
+	(
+		cd 5a &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		mkdir y &&
+		echo d >y/d &&
+		git add z y &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		echo e1 >z/e &&
+		echo f >z/f &&
+		echo e2 >y/e &&
+		git add z/e z/f y/e &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv z/b y/ &&
+		git mv z/c y/ &&
+		rmdir z &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '5a-check: Merge directories, other side adds files to original and target' '
+	(
+		cd 5a &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT.*implicit dir rename" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 6 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			:0:y/b :0:y/c :0:y/d :0:y/e :0:z/e :0:y/f &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  O:y/d  A:y/e  A:z/e  A:z/f &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 5b, Rename/delete in order to get add/add/add conflict
+#   (Related to testcase 8d; these may appear slightly inconsistent to users;
+#    Also related to testcases 7d and 7e)
+#   Commit O: z/{b,c,d_1}
+#   Commit A: y/{b,c,d_2}
+#   Commit B: z/{b,c,d_1,e}, y/d_3
+#   Expected: y/{b,c,e}, CONFLICT(add/add: y/d_2 vs. y/d_3)
+#   NOTE: If z/d_1 in commit B were to be involved in dir rename detection, as
+#         we normaly would since z/ is being renamed to y/, then this would be
+#         a rename/delete (z/d_1 -> y/d_1 vs. deleted) AND an add/add/add
+#         conflict of y/d_1 vs. y/d_2 vs. y/d_3.  Add/add/add is not
+#         representable in the index, so the existence of y/d_3 needs to
+#         cause us to bail on directory rename detection for that path, falling
+#         back to git behavior without the directory rename detection.
+
+test_expect_success '5b-setup: Rename/delete in order to get add/add/add conflict' '
+	test_create_repo 5b &&
+	(
+		cd 5b &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		echo d1 >z/d &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git rm z/d &&
+		git mv z y &&
+		echo d2 >y/d &&
+		git add y/d &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		mkdir y &&
+		echo d3 >y/d &&
+		echo e >z/e &&
+		git add y/d z/e &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '5b-check: Rename/delete in order to get add/add/add conflict' '
+	(
+		cd 5b &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT (add/add).* y/d" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 5 out &&
+		git ls-files -u >out &&
+		test_line_count = 2 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			:0:y/b :0:y/c :0:y/e :2:y/d :3:y/d &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  B:z/e  A:y/d  B:y/d &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse :1:y/d &&
+		test_path_is_file y/d
+	)
+'
+
+# Testcase 5c, Transitive rename would cause rename/rename/rename/add/add/add
+#   (Directory rename detection would result in transitive rename vs.
+#    rename/rename(1to2) and turn it into a rename/rename(1to3).  Further,
+#    rename paths conflict with separate adds on the other side)
+#   (Related to testcases 3b and 7c)
+#   Commit O: z/{b,c}, x/d_1
+#   Commit A: y/{b,c,d_2}, w/d_1
+#   Commit B: z/{b,c,d_1,e}, w/d_3, y/d_4
+#   Expected: A mess, but only a rename/rename(1to2)/add/add mess.  Use the
+#             presence of y/d_4 in B to avoid doing transitive rename of
+#             x/d_1 -> z/d_1 -> y/d_1, so that the only paths we have at
+#             y/d are y/d_2 and y/d_4.  We still do the move from z/e to y/e,
+#             though, because it doesn't have anything in the way.
+
+test_expect_success '5c-setup: Transitive rename would cause rename/rename/rename/add/add/add' '
+	test_create_repo 5c &&
+	(
+		cd 5c &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		mkdir x &&
+		echo d1 >x/d &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		echo d2 >y/d &&
+		git add y/d &&
+		git mv x w &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/d z/ &&
+		mkdir w &&
+		mkdir y &&
+		echo d3 >w/d &&
+		echo d4 >y/d &&
+		echo e >z/e &&
+		git add w/ y/ z/e &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '5c-check: Transitive rename would cause rename/rename/rename/add/add/add' '
+	(
+		cd 5c &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT (rename/rename).*x/d.*w/d.*z/d" out &&
+		test_i18ngrep "CONFLICT (add/add).* y/d" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 9 out &&
+		git ls-files -u >out &&
+		test_line_count = 6 out &&
+		git ls-files -o >out &&
+		test_line_count = 3 out &&
+
+		git rev-parse >actual \
+			:0:y/b :0:y/c :0:y/e &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  B:z/e &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse :1:y/d &&
+		git rev-parse >actual \
+			:2:w/d :3:w/d :1:x/d :2:y/d :3:y/d :3:z/d &&
+		git rev-parse >expect \
+			 O:x/d  B:w/d  O:x/d  A:y/d  B:y/d  O:x/d &&
+		test_cmp expect actual &&
+
+		git hash-object >actual \
+			w/d~HEAD w/d~B^0 z/d &&
+		git rev-parse >expect \
+			O:x/d    B:w/d   O:x/d &&
+		test_cmp expect actual &&
+		test_path_is_missing x/d &&
+		test_path_is_file y/d &&
+		grep -q "<<<<" y/d  # conflict markers should be present
+	)
+'
+
+# Testcase 5d, Directory/file/file conflict due to directory rename
+#   Commit O: z/{b,c}
+#   Commit A: y/{b,c,d_1}
+#   Commit B: z/{b,c,d_2,f}, y/d/e
+#   Expected: y/{b,c,d/e,f}, z/d_2, CONFLICT(file/directory), y/d_1~HEAD
+#   Note: The fact that y/d/ exists in B makes us bail on directory rename
+#         detection for z/d_2, but that doesn't prevent us from applying the
+#         directory rename detection for z/f -> y/f.
+
+test_expect_success '5d-setup: Directory/file/file conflict due to directory rename' '
+	test_create_repo 5d &&
+	(
+		cd 5d &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		echo d1 >y/d &&
+		git add y/d &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		mkdir -p y/d &&
+		echo e >y/d/e &&
+		echo d2 >z/d &&
+		echo f >z/f &&
+		git add y/d/e z/d z/f &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '5d-check: Directory/file/file conflict due to directory rename' '
+	(
+		cd 5d &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT (file/directory).*y/d" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 6 out &&
+		git ls-files -u >out &&
+		test_line_count = 1 out &&
+		git ls-files -o >out &&
+		test_line_count = 2 out &&
+
+		git rev-parse >actual \
+			:0:y/b :0:y/c :0:z/d :0:y/f :2:y/d :0:y/d/e &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  B:z/d  B:z/f  A:y/d  B:y/d/e &&
+		test_cmp expect actual &&
+
+		git hash-object y/d~HEAD >actual &&
+		git rev-parse A:y/d >expect &&
+		test_cmp expect actual
+	)
+'
+
+###########################################################################
+# Rules suggested by section 5:
+#
+#   If a subset of to-be-renamed files have a file or directory in the way,
+#   "turn off" the directory rename for those specific sub-paths, falling
+#   back to old handling.  But, sadly, see testcases 8a and 8b.
+###########################################################################
+
+
+###########################################################################
+# SECTION 6: Same side of the merge was the one that did the rename
+#
+# It may sound obvious that you only want to apply implicit directory
+# renames to directories if the _other_ side of history did the renaming.
+# If you did make an implementation that didn't explicitly enforce this
+# rule, the majority of cases that would fall under this section would
+# also be solved by following the rules from the above sections.  But
+# there are still a few that stick out, so this section covers them just
+# to make sure we also get them right.
+###########################################################################
+
+# Testcase 6a, Tricky rename/delete
+#   Commit O: z/{b,c,d}
+#   Commit A: z/b
+#   Commit B: y/{b,c}, z/d
+#   Expected: y/b, CONFLICT(rename/delete, z/c -> y/c vs. NULL)
+#   Note: We're just checking here that the rename of z/b and z/c to put
+#         them under y/ doesn't accidentally catch z/d and make it look like
+#         it is also involved in a rename/delete conflict.
+
+test_expect_success '6a-setup: Tricky rename/delete' '
+	test_create_repo 6a &&
+	(
+		cd 6a &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		echo d >z/d &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git rm z/c &&
+		git rm z/d &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		mkdir y &&
+		git mv z/b y/ &&
+		git mv z/c y/ &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '6a-check: Tricky rename/delete' '
+	(
+		cd 6a &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT (rename/delete).*z/c.*y/c" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 2 out &&
+		git ls-files -u >out &&
+		test_line_count = 1 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			:0:y/b :3:y/c &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 6b, Same rename done on both sides
+#   (Related to testcases 6c and 8e)
+#   Commit O: z/{b,c}
+#   Commit A: y/{b,c}
+#   Commit B: y/{b,c}, z/d
+#   Expected: y/{b,c}, z/d
+#   Note: If we did directory rename detection here, we'd move z/d into y/,
+#         but B did that rename and still decided to put the file into z/,
+#         so we probably shouldn't apply directory rename detection for it.
+
+test_expect_success '6b-setup: Same rename done on both sides' '
+	test_create_repo 6b &&
+	(
+		cd 6b &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv z y &&
+		mkdir z &&
+		echo d >z/d &&
+		git add z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '6b-check: Same rename done on both sides' '
+	(
+		cd 6b &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:z/d &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    B:z/d &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 6c, Rename only done on same side
+#   (Related to testcases 6b and 8e)
+#   Commit O: z/{b,c}
+#   Commit A: z/{b,c} (no change)
+#   Commit B: y/{b,c}, z/d
+#   Expected: y/{b,c}, z/d
+#   NOTE: Seems obvious, but just checking that the implementation doesn't
+#         "accidentally detect a rename" and give us y/{b,c,d}.
+
+test_expect_success '6c-setup: Rename only done on same side' '
+	test_create_repo 6c &&
+	(
+		cd 6c &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_tick &&
+		git commit --allow-empty -m "A" &&
+
+		git checkout B &&
+		git mv z y &&
+		mkdir z &&
+		echo d >z/d &&
+		git add z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '6c-check: Rename only done on same side' '
+	(
+		cd 6c &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:z/d &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    B:z/d &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 6d, We don't always want transitive renaming
+#   (Related to testcase 1c)
+#   Commit O: z/{b,c}, x/d
+#   Commit A: z/{b,c}, x/d (no change)
+#   Commit B: y/{b,c}, z/d
+#   Expected: y/{b,c}, z/d
+#   NOTE: Again, this seems obvious but just checking that the implementation
+#         doesn't "accidentally detect a rename" and give us y/{b,c,d}.
+
+test_expect_success '6d-setup: We do not always want transitive renaming' '
+	test_create_repo 6d &&
+	(
+		cd 6d &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		mkdir x &&
+		echo d >x/d &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_tick &&
+		git commit --allow-empty -m "A" &&
+
+		git checkout B &&
+		git mv z y &&
+		git mv x z &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '6d-check: We do not always want transitive renaming' '
+	(
+		cd 6d &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:z/d &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    O:x/d &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 6e, Add/add from one-side
+#   Commit O: z/{b,c}
+#   Commit A: z/{b,c} (no change)
+#   Commit B: y/{b,c,d_1}, z/d_2
+#   Expected: y/{b,c,d_1}, z/d_2
+#   NOTE: Again, this seems obvious but just checking that the implementation
+#         doesn't "accidentally detect a rename" and give us y/{b,c} +
+#         add/add conflict on y/d_1 vs y/d_2.
+
+test_expect_success '6e-setup: Add/add from one side' '
+	test_create_repo 6e &&
+	(
+		cd 6e &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_tick &&
+		git commit --allow-empty -m "A" &&
+
+		git checkout B &&
+		git mv z y &&
+		echo d1 > y/d &&
+		mkdir z &&
+		echo d2 > z/d &&
+		git add y/d z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '6e-check: Add/add from one side' '
+	(
+		cd 6e &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 4 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:y/d HEAD:z/d &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    B:y/d    B:z/d &&
+		test_cmp expect actual
+	)
+'
+
+###########################################################################
+# Rules suggested by section 6:
+#
+#   Only apply implicit directory renames to directories if the other
+#   side of history is the one doing the renaming.
+###########################################################################
+
+
+###########################################################################
+# SECTION 7: More involved Edge/Corner cases
+#
+# The ruleset we have generated in the above sections seems to provide
+# well-defined merges.  But can we find edge/corner cases that either (a)
+# are harder for users to understand, or (b) have a resolution that is
+# non-intuitive or suboptimal?
+#
+# The testcases in this section dive into cases that I've tried to craft in
+# a way to find some that might be surprising to users or difficult for
+# them to understand (the next section will look at non-intuitive or
+# suboptimal merge results).  Some of the testcases are similar to ones
+# from past sections, but have been simplified to try to highlight error
+# messages using a "modified" path (due to the directory rename).  Are
+# users okay with these?
+#
+# In my opinion, testcases that are difficult to understand from this
+# section is due to difficulty in the testcase rather than the directory
+# renaming (similar to how t6042 and t6036 have difficult resolutions due
+# to the problem setup itself being complex).  And I don't think the
+# error messages are a problem.
+#
+# On the other hand, the testcases in section 8 worry me slightly more...
+###########################################################################
+
+# Testcase 7a, rename-dir vs. rename-dir (NOT split evenly) PLUS add-other-file
+#   Commit O: z/{b,c}
+#   Commit A: y/{b,c}
+#   Commit B: w/b, x/c, z/d
+#   Expected: y/d, CONFLICT(rename/rename for both z/b and z/c)
+#   NOTE: There's a rename of z/ here, y/ has more renames, so z/d -> y/d.
+
+test_expect_success '7a-setup: rename-dir vs. rename-dir (NOT split evenly) PLUS add-other-file' '
+	test_create_repo 7a &&
+	(
+		cd 7a &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		mkdir w &&
+		mkdir x &&
+		git mv z/b w/ &&
+		git mv z/c x/ &&
+		echo d > z/d &&
+		git add z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '7a-check: rename-dir vs. rename-dir (NOT split evenly) PLUS add-other-file' '
+	(
+		cd 7a &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT (rename/rename).*z/b.*y/b.*w/b" out &&
+		test_i18ngrep "CONFLICT (rename/rename).*z/c.*y/c.*x/c" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 7 out &&
+		git ls-files -u >out &&
+		test_line_count = 6 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			:1:z/b :2:y/b :3:w/b :1:z/c :2:y/c :3:x/c :0:y/d &&
+		git rev-parse >expect \
+			 O:z/b  O:z/b  O:z/b  O:z/c  O:z/c  O:z/c  B:z/d &&
+		test_cmp expect actual &&
+
+		git hash-object >actual \
+			y/b   w/b   y/c   x/c &&
+		git rev-parse >expect \
+			O:z/b O:z/b O:z/c O:z/c &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 7b, rename/rename(2to1), but only due to transitive rename
+#   (Related to testcase 1d)
+#   Commit O: z/{b,c},     x/d_1, w/d_2
+#   Commit A: y/{b,c,d_2}, x/d_1
+#   Commit B: z/{b,c,d_1},        w/d_2
+#   Expected: y/{b,c}, CONFLICT(rename/rename(2to1): x/d_1, w/d_2 -> y_d)
+
+test_expect_success '7b-setup: rename/rename(2to1), but only due to transitive rename' '
+	test_create_repo 7b &&
+	(
+		cd 7b &&
+
+		mkdir z &&
+		mkdir x &&
+		mkdir w &&
+		echo b >z/b &&
+		echo c >z/c &&
+		echo d1 > x/d &&
+		echo d2 > w/d &&
+		git add z x w &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		git mv w/d y/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/d z/ &&
+		rmdir x &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '7b-check: rename/rename(2to1), but only due to transitive rename' '
+	(
+		cd 7b &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT (rename/rename)" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 4 out &&
+		git ls-files -u >out &&
+		test_line_count = 2 out &&
+		git ls-files -o >out &&
+		test_line_count = 3 out &&
+
+		git rev-parse >actual \
+			:0:y/b :0:y/c :2:y/d :3:y/d &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  O:w/d  O:x/d &&
+		test_cmp expect actual &&
+
+		test_path_is_missing y/d &&
+		test_path_is_file y/d~HEAD &&
+		test_path_is_file y/d~B^0 &&
+
+		git hash-object >actual \
+			y/d~HEAD y/d~B^0 &&
+		git rev-parse >expect \
+			O:w/d    O:x/d &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 7c, rename/rename(1to...2or3); transitive rename may add complexity
+#   (Related to testcases 3b and 5c)
+#   Commit O: z/{b,c}, x/d
+#   Commit A: y/{b,c}, w/d
+#   Commit B: z/{b,c,d}
+#   Expected: y/{b,c}, CONFLICT(x/d -> w/d vs. y/d)
+#   NOTE: z/ was renamed to y/ so we do want to report
+#         neither CONFLICT(x/d -> w/d vs. z/d)
+#         nor CONFLiCT x/d -> w/d vs. y/d vs. z/d)
+
+test_expect_success '7c-setup: rename/rename(1to...2or3); transitive rename may add complexity' '
+	test_create_repo 7c &&
+	(
+		cd 7c &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		mkdir x &&
+		echo d >x/d &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		git mv x w &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/d z/ &&
+		rmdir x &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '7c-check: rename/rename(1to...2or3); transitive rename may add complexity' '
+	(
+		cd 7c &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT (rename/rename).*x/d.*w/d.*y/d" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 5 out &&
+		git ls-files -u >out &&
+		test_line_count = 3 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			:0:y/b :0:y/c :1:x/d :2:w/d :3:y/d &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  O:x/d  O:x/d  O:x/d &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 7d, transitive rename involved in rename/delete; how is it reported?
+#   (Related somewhat to testcases 5b and 8d)
+#   Commit O: z/{b,c}, x/d
+#   Commit A: y/{b,c}
+#   Commit B: z/{b,c,d}
+#   Expected: y/{b,c}, CONFLICT(delete x/d vs rename to y/d)
+#   NOTE: z->y so NOT CONFLICT(delete x/d vs rename to z/d)
+
+test_expect_success '7d-setup: transitive rename involved in rename/delete; how is it reported?' '
+	test_create_repo 7d &&
+	(
+		cd 7d &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		mkdir x &&
+		echo d >x/d &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		git rm -rf x &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/d z/ &&
+		rmdir x &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '7d-check: transitive rename involved in rename/delete; how is it reported?' '
+	(
+		cd 7d &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT (rename/delete).*x/d.*y/d" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+		git ls-files -u >out &&
+		test_line_count = 1 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			:0:y/b :0:y/c :3:y/d &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  O:x/d &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 7e, transitive rename in rename/delete AND dirs in the way
+#   (Very similar to 'both rename source and destination involved in D/F conflict' from t6022-merge-rename.sh)
+#   (Also related to testcases 9c and 9d)
+#   Commit O: z/{b,c},     x/d_1
+#   Commit A: y/{b,c,d/g}, x/d/f
+#   Commit B: z/{b,c,d_1}
+#   Expected: rename/delete(x/d_1->y/d_1 vs. None) + D/F conflict on y/d
+#             y/{b,c,d/g}, y/d_1~B^0, x/d/f
+
+#   NOTE: The main path of interest here is d_1 and where it ends up, but
+#         this is actually a case that has two potential directory renames
+#         involved and D/F conflict(s), so it makes sense to walk through
+#         each step.
+#
+#         Commit A renames z/ -> y/.  Thus everything that B adds to z/
+#         should be instead moved to y/.  This gives us the D/F conflict on
+#         y/d because x/d_1 -> z/d_1 -> y/d_1 conflicts with y/d/g.
+#
+#         Further, commit B renames x/ -> z/, thus everything A adds to x/
+#         should instead be moved to z/...BUT we removed z/ and renamed it
+#         to y/, so maybe everything should move not from x/ to z/, but
+#         from x/ to z/ to y/.  Doing so might make sense from the logic so
+#         far, but note that commit A had both an x/ and a y/; it did the
+#         renaming of z/ to y/ and created x/d/f and it clearly made these
+#         things separate, so it doesn't make much sense to push these
+#         together.  Doing so is what I'd call a doubly transitive rename;
+#         see testcases 9c and 9d for further discussion of this issue and
+#         how it's resolved.
+
+test_expect_success '7e-setup: transitive rename in rename/delete AND dirs in the way' '
+	test_create_repo 7e &&
+	(
+		cd 7e &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		mkdir x &&
+		echo d1 >x/d &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		git rm x/d &&
+		mkdir -p x/d &&
+		mkdir -p y/d &&
+		echo f >x/d/f &&
+		echo g >y/d/g &&
+		git add x/d/f y/d/g &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/d z/ &&
+		rmdir x &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '7e-check: transitive rename in rename/delete AND dirs in the way' '
+	(
+		cd 7e &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT (rename/delete).*x/d.*y/d" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 5 out &&
+		git ls-files -u >out &&
+		test_line_count = 1 out &&
+		git ls-files -o >out &&
+		test_line_count = 2 out &&
+
+		git rev-parse >actual \
+			:0:x/d/f :0:y/d/g :0:y/b :0:y/c :3:y/d &&
+		git rev-parse >expect \
+			 A:x/d/f  A:y/d/g  O:z/b  O:z/c  O:x/d &&
+		test_cmp expect actual &&
+
+		git hash-object y/d~B^0 >actual &&
+		git rev-parse O:x/d >expect &&
+		test_cmp expect actual
+	)
+'
+
+###########################################################################
+# SECTION 8: Suboptimal merges
+#
+# As alluded to in the last section, the ruleset we have built up for
+# detecting directory renames unfortunately has some special cases where it
+# results in slightly suboptimal or non-intuitive behavior.  This section
+# explores these cases.
+#
+# To be fair, we already had non-intuitive or suboptimal behavior for most
+# of these cases in git before introducing implicit directory rename
+# detection, but it'd be nice if there was a modified ruleset out there
+# that handled these cases a bit better.
+###########################################################################
+
+# Testcase 8a, Dual-directory rename, one into the others' way
+#   Commit O. x/{a,b},   y/{c,d}
+#   Commit A. x/{a,b,e}, y/{c,d,f}
+#   Commit B. y/{a,b},   z/{c,d}
+#
+# Possible Resolutions:
+#   w/o dir-rename detection: y/{a,b,f},   z/{c,d},   x/e
+#   Currently expected:       y/{a,b,e,f}, z/{c,d}
+#   Optimal:                  y/{a,b,e},   z/{c,d,f}
+#
+# Note: Both x and y got renamed and it'd be nice to detect both, and we do
+# better with directory rename detection than git did without, but the
+# simple rule from section 5 prevents me from handling this as optimally as
+# we potentially could.
+
+test_expect_success '8a-setup: Dual-directory rename, one into the others way' '
+	test_create_repo 8a &&
+	(
+		cd 8a &&
+
+		mkdir x &&
+		mkdir y &&
+		echo a >x/a &&
+		echo b >x/b &&
+		echo c >y/c &&
+		echo d >y/d &&
+		git add x y &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		echo e >x/e &&
+		echo f >y/f &&
+		git add x/e y/f &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv y z &&
+		git mv x y &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '8a-check: Dual-directory rename, one into the others way' '
+	(
+		cd 8a &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 6 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			HEAD:y/a HEAD:y/b HEAD:y/e HEAD:y/f HEAD:z/c HEAD:z/d &&
+		git rev-parse >expect \
+			O:x/a    O:x/b    A:x/e    A:y/f    O:y/c    O:y/d &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 8b, Dual-directory rename, one into the others' way, with conflicting filenames
+#   Commit O. x/{a_1,b_1},     y/{a_2,b_2}
+#   Commit A. x/{a_1,b_1,e_1}, y/{a_2,b_2,e_2}
+#   Commit B. y/{a_1,b_1},     z/{a_2,b_2}
+#
+#   w/o dir-rename detection: y/{a_1,b_1,e_2}, z/{a_2,b_2}, x/e_1
+#   Currently expected:       <same>
+#   Scary:                    y/{a_1,b_1},     z/{a_2,b_2}, CONFLICT(add/add, e_1 vs. e_2)
+#   Optimal:                  y/{a_1,b_1,e_1}, z/{a_2,b_2,e_2}
+#
+# Note: Very similar to 8a, except instead of 'e' and 'f' in directories x and
+# y, both are named 'e'.  Without directory rename detection, neither file
+# moves directories.  Implement directory rename detection suboptimally, and
+# you get an add/add conflict, but both files were added in commit A, so this
+# is an add/add conflict where one side of history added both files --
+# something we can't represent in the index.  Obviously, we'd prefer the last
+# resolution, but our previous rules are too coarse to allow it.  Using both
+# the rules from section 4 and section 5 save us from the Scary resolution,
+# making us fall back to pre-directory-rename-detection behavior for both
+# e_1 and e_2.
+
+test_expect_success '8b-setup: Dual-directory rename, one into the others way, with conflicting filenames' '
+	test_create_repo 8b &&
+	(
+		cd 8b &&
+
+		mkdir x &&
+		mkdir y &&
+		echo a1 >x/a &&
+		echo b1 >x/b &&
+		echo a2 >y/a &&
+		echo b2 >y/b &&
+		git add x y &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		echo e1 >x/e &&
+		echo e2 >y/e &&
+		git add x/e y/e &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv y z &&
+		git mv x y &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '8b-check: Dual-directory rename, one into the others way, with conflicting filenames' '
+	(
+		cd 8b &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 6 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			HEAD:y/a HEAD:y/b HEAD:z/a HEAD:z/b HEAD:x/e HEAD:y/e &&
+		git rev-parse >expect \
+			O:x/a    O:x/b    O:y/a    O:y/b    A:x/e    A:y/e &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 8c, modify/delete or rename+modify/delete?
+#   (Related to testcases 5b, 8d, and 9h)
+#   Commit O: z/{b,c,d}
+#   Commit A: y/{b,c}
+#   Commit B: z/{b,c,d_modified,e}
+#   Expected: y/{b,c,e}, CONFLICT(modify/delete: on z/d)
+#
+#   Note: It could easily be argued that the correct resolution here is
+#         y/{b,c,e}, CONFLICT(rename/delete: z/d -> y/d vs deleted)
+#         and that the modifed version of d should be present in y/ after
+#         the merge, just marked as conflicted.  Indeed, I previously did
+#         argue that.  But applying directory renames to the side of
+#         history where a file is merely modified results in spurious
+#         rename/rename(1to2) conflicts -- see testcase 9h.  See also
+#         notes in 8d.
+
+test_expect_success '8c-setup: modify/delete or rename+modify/delete?' '
+	test_create_repo 8c &&
+	(
+		cd 8c &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		test_seq 1 10 >z/d &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git rm z/d &&
+		git mv z y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo 11 >z/d &&
+		test_chmod +x z/d &&
+		echo e >z/e &&
+		git add z/d z/e &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '8c-check: modify/delete or rename+modify/delete' '
+	(
+		cd 8c &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		test_i18ngrep "CONFLICT (modify/delete).* z/d" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 5 out &&
+		git ls-files -u >out &&
+		test_line_count = 2 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			:0:y/b :0:y/c :0:y/e :1:z/d :3:z/d &&
+		git rev-parse >expect \
+			 O:z/b  O:z/c  B:z/e  O:z/d  B:z/d &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse :2:z/d &&
+		git ls-files -s z/d | grep ^100755 &&
+		test_path_is_file z/d &&
+		test_path_is_missing y/d
+	)
+'
+
+# Testcase 8d, rename/delete...or not?
+#   (Related to testcase 5b; these may appear slightly inconsistent to users;
+#    Also related to testcases 7d and 7e)
+#   Commit O: z/{b,c,d}
+#   Commit A: y/{b,c}
+#   Commit B: z/{b,c,d,e}
+#   Expected: y/{b,c,e}
+#
+#   Note: It would also be somewhat reasonable to resolve this as
+#             y/{b,c,e}, CONFLICT(rename/delete: x/d -> y/d or deleted)
+#
+#   In this case, I'm leaning towards: commit A was the one that deleted z/d
+#   and it did the rename of z to y, so the two "conflicts" (rename vs.
+#   delete) are both coming from commit A, which is illogical.  Conflicts
+#   during merging are supposed to be about opposite sides doing things
+#   differently.
+
+test_expect_success '8d-setup: rename/delete...or not?' '
+	test_create_repo 8d &&
+	(
+		cd 8d &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		test_seq 1 10 >z/d &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git rm z/d &&
+		git mv z y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo e >z/e &&
+		git add z/e &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '8d-check: rename/delete...or not?' '
+	(
+		cd 8d &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:y/e &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    B:z/e &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 8e, Both sides rename, one side adds to original directory
+#   Commit O: z/{b,c}
+#   Commit A: y/{b,c}
+#   Commit B: w/{b,c}, z/d
+#
+# Possible Resolutions:
+#   w/o dir-rename detection: z/d, CONFLICT(z/b -> y/b vs. w/b),
+#                                  CONFLICT(z/c -> y/c vs. w/c)
+#   Currently expected:       y/d, CONFLICT(z/b -> y/b vs. w/b),
+#                                  CONFLICT(z/c -> y/c vs. w/c)
+#   Optimal:                  ??
+#
+# Notes: In commit A, directory z got renamed to y.  In commit B, directory z
+#        did NOT get renamed; the directory is still present; instead it is
+#        considered to have just renamed a subset of paths in directory z
+#        elsewhere.  Therefore, the directory rename done in commit A to z/
+#        applies to z/d and maps it to y/d.
+#
+#        It's possible that users would get confused about this, but what
+#        should we do instead?  Silently leaving at z/d seems just as bad or
+#        maybe even worse.  Perhaps we could print a big warning about z/d
+#        and how we're moving to y/d in this case, but when I started thinking
+#        about the ramifications of doing that, I didn't know how to rule out
+#        that opening other weird edge and corner cases so I just punted.
+
+test_expect_success '8e-setup: Both sides rename, one side adds to original directory' '
+	test_create_repo 8e &&
+	(
+		cd 8e &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv z w &&
+		mkdir z &&
+		echo d >z/d &&
+		git add z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '8e-check: Both sides rename, one side adds to original directory' '
+	(
+		cd 8e &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep CONFLICT.*rename/rename.*z/c.*y/c.*w/c out &&
+		test_i18ngrep CONFLICT.*rename/rename.*z/b.*y/b.*w/b out &&
+
+		git ls-files -s >out &&
+		test_line_count = 7 out &&
+		git ls-files -u >out &&
+		test_line_count = 6 out &&
+		git ls-files -o >out &&
+		test_line_count = 2 out &&
+
+		git rev-parse >actual \
+			:1:z/b :2:y/b :3:w/b :1:z/c :2:y/c :3:w/c :0:y/d &&
+		git rev-parse >expect \
+			 O:z/b  O:z/b  O:z/b  O:z/c  O:z/c  O:z/c  B:z/d &&
+		test_cmp expect actual &&
+
+		git hash-object >actual \
+			y/b   w/b   y/c   w/c &&
+		git rev-parse >expect \
+			O:z/b O:z/b O:z/c O:z/c &&
+		test_cmp expect actual &&
+
+		test_path_is_missing z/b &&
+		test_path_is_missing z/c
+	)
+'
+
+###########################################################################
+# SECTION 9: Other testcases
+#
+# This section consists of miscellaneous testcases I thought of during
+# the implementation which round out the testing.
+###########################################################################
+
+# Testcase 9a, Inner renamed directory within outer renamed directory
+#   (Related to testcase 1f)
+#   Commit O: z/{b,c,d/{e,f,g}}
+#   Commit A: y/{b,c}, x/w/{e,f,g}
+#   Commit B: z/{b,c,d/{e,f,g,h},i}
+#   Expected: y/{b,c,i}, x/w/{e,f,g,h}
+#   NOTE: The only reason this one is interesting is because when a directory
+#         is split into multiple other directories, we determine by the weight
+#         of which one had the most paths going to it.  A naive implementation
+#         of that could take the new file in commit B at z/i to x/w/i or x/i.
+
+test_expect_success '9a-setup: Inner renamed directory within outer renamed directory' '
+	test_create_repo 9a &&
+	(
+		cd 9a &&
+
+		mkdir -p z/d &&
+		echo b >z/b &&
+		echo c >z/c &&
+		echo e >z/d/e &&
+		echo f >z/d/f &&
+		echo g >z/d/g &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		mkdir x &&
+		git mv z/d x/w &&
+		git mv z y &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo h >z/d/h &&
+		echo i >z/i &&
+		git add z &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '9a-check: Inner renamed directory within outer renamed directory' '
+	(
+		cd 9a &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 7 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:y/i &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    B:z/i &&
+		test_cmp expect actual &&
+
+		git rev-parse >actual \
+			HEAD:x/w/e HEAD:x/w/f HEAD:x/w/g HEAD:x/w/h &&
+		git rev-parse >expect \
+			O:z/d/e    O:z/d/f    O:z/d/g    B:z/d/h &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 9b, Transitive rename with content merge
+#   (Related to testcase 1c)
+#   Commit O: z/{b,c},   x/d_1
+#   Commit A: y/{b,c},   x/d_2
+#   Commit B: z/{b,c,d_3}
+#   Expected: y/{b,c,d_merged}
+
+test_expect_success '9b-setup: Transitive rename with content merge' '
+	test_create_repo 9b &&
+	(
+		cd 9b &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		mkdir x &&
+		test_seq 1 10 >x/d &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		test_seq 1 11 >x/d &&
+		git add x/d &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		test_seq 0 10 >x/d &&
+		git mv x/d z/d &&
+		git add z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '9b-check: Transitive rename with content merge' '
+	(
+		cd 9b &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+
+		test_seq 0 11 >expected &&
+		test_cmp expected y/d &&
+		git add expected &&
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:y/d &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    :0:expected &&
+		test_cmp expect actual &&
+		test_must_fail git rev-parse HEAD:x/d &&
+		test_must_fail git rev-parse HEAD:z/d &&
+		test_path_is_missing z/d &&
+
+		test $(git rev-parse HEAD:y/d) != $(git rev-parse O:x/d) &&
+		test $(git rev-parse HEAD:y/d) != $(git rev-parse A:x/d) &&
+		test $(git rev-parse HEAD:y/d) != $(git rev-parse B:z/d)
+	)
+'
+
+# Testcase 9c, Doubly transitive rename?
+#   (Related to testcase 1c, 7e, and 9d)
+#   Commit O: z/{b,c},     x/{d,e},    w/f
+#   Commit A: y/{b,c},     x/{d,e,f,g}
+#   Commit B: z/{b,c,d,e},             w/f
+#   Expected: y/{b,c,d,e}, x/{f,g}
+#
+#   NOTE: x/f and x/g may be slightly confusing here.  The rename from w/f to
+#         x/f is clear.  Let's look beyond that.  Here's the logic:
+#            Commit B renamed x/ -> z/
+#            Commit A renamed z/ -> y/
+#         So, we could possibly further rename x/f to z/f to y/f, a doubly
+#         transient rename.  However, where does it end?  We can chain these
+#         indefinitely (see testcase 9d).  What if there is a D/F conflict
+#         at z/f/ or y/f/?  Or just another file conflict at one of those
+#         paths?  In the case of an N-long chain of transient renamings,
+#         where do we "abort" the rename at?  Can the user make sense of
+#         the resulting conflict and resolve it?
+#
+#         To avoid this confusion I use the simple rule that if the other side
+#         of history did a directory rename to a path that your side renamed
+#         away, then ignore that particular rename from the other side of
+#         history for any implicit directory renames.
+
+test_expect_success '9c-setup: Doubly transitive rename?' '
+	test_create_repo 9c &&
+	(
+		cd 9c &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		mkdir x &&
+		echo d >x/d &&
+		echo e >x/e &&
+		mkdir w &&
+		echo f >w/f &&
+		git add z x w &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z y &&
+		git mv w/f x/ &&
+		echo g >x/g &&
+		git add x/g &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/d z/d &&
+		git mv x/e z/e &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '9c-check: Doubly transitive rename?' '
+	(
+		cd 9c &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 >out &&
+		test_i18ngrep "WARNING: Avoiding applying x -> z rename to x/f" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 6 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:y/d HEAD:y/e HEAD:x/f HEAD:x/g &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    O:x/d    O:x/e    O:w/f    A:x/g &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 9d, N-fold transitive rename?
+#   (Related to testcase 9c...and 1c and 7e)
+#   Commit O: z/a, y/b, x/c, w/d, v/e, u/f
+#   Commit A:  y/{a,b},  w/{c,d},  u/{e,f}
+#   Commit B: z/{a,t}, x/{b,c}, v/{d,e}, u/f
+#   Expected: <see NOTE first>
+#
+#   NOTE: z/ -> y/ (in commit A)
+#         y/ -> x/ (in commit B)
+#         x/ -> w/ (in commit A)
+#         w/ -> v/ (in commit B)
+#         v/ -> u/ (in commit A)
+#         So, if we add a file to z, say z/t, where should it end up?  In u?
+#         What if there's another file or directory named 't' in one of the
+#         intervening directories and/or in u itself?  Also, shouldn't the
+#         same logic that places 't' in u/ also move ALL other files to u/?
+#         What if there are file or directory conflicts in any of them?  If
+#         we attempted to do N-way (N-fold? N-ary? N-uple?) transitive renames
+#         like this, would the user have any hope of understanding any
+#         conflicts or how their working tree ended up?  I think not, so I'm
+#         ruling out N-ary transitive renames for N>1.
+#
+#   Therefore our expected result is:
+#     z/t, y/a, x/b, w/c, u/d, u/e, u/f
+#   The reason that v/d DOES get transitively renamed to u/d is that u/ isn't
+#   renamed somewhere.  A slightly sub-optimal result, but it uses fairly
+#   simple rules that are consistent with what we need for all the other
+#   testcases and simplifies things for the user.
+
+test_expect_success '9d-setup: N-way transitive rename?' '
+	test_create_repo 9d &&
+	(
+		cd 9d &&
+
+		mkdir z y x w v u &&
+		echo a >z/a &&
+		echo b >y/b &&
+		echo c >x/c &&
+		echo d >w/d &&
+		echo e >v/e &&
+		echo f >u/f &&
+		git add z y x w v u &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z/a y/ &&
+		git mv x/c w/ &&
+		git mv v/e u/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo t >z/t &&
+		git mv y/b x/ &&
+		git mv w/d v/ &&
+		git add z/t &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '9d-check: N-way transitive rename?' '
+	(
+		cd 9d &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 >out &&
+		test_i18ngrep "WARNING: Avoiding applying z -> y rename to z/t" out &&
+		test_i18ngrep "WARNING: Avoiding applying y -> x rename to y/a" out &&
+		test_i18ngrep "WARNING: Avoiding applying x -> w rename to x/b" out &&
+		test_i18ngrep "WARNING: Avoiding applying w -> v rename to w/c" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 7 out &&
+		git ls-files -o >out &&
+		test_line_count = 1 out &&
+
+		git rev-parse >actual \
+			HEAD:z/t \
+			HEAD:y/a HEAD:x/b HEAD:w/c \
+			HEAD:u/d HEAD:u/e HEAD:u/f &&
+		git rev-parse >expect \
+			B:z/t    \
+			O:z/a    O:y/b    O:x/c    \
+			O:w/d    O:v/e    A:u/f &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 9e, N-to-1 whammo
+#   (Related to testcase 9c...and 1c and 7e)
+#   Commit O: dir1/{a,b}, dir2/{d,e}, dir3/{g,h}, dirN/{j,k}
+#   Commit A: dir1/{a,b,c,yo}, dir2/{d,e,f,yo}, dir3/{g,h,i,yo}, dirN/{j,k,l,yo}
+#   Commit B: combined/{a,b,d,e,g,h,j,k}
+#   Expected: combined/{a,b,c,d,e,f,g,h,i,j,k,l}, CONFLICT(Nto1) warnings,
+#             dir1/yo, dir2/yo, dir3/yo, dirN/yo
+
+test_expect_success '9e-setup: N-to-1 whammo' '
+	test_create_repo 9e &&
+	(
+		cd 9e &&
+
+		mkdir dir1 dir2 dir3 dirN &&
+		echo a >dir1/a &&
+		echo b >dir1/b &&
+		echo d >dir2/d &&
+		echo e >dir2/e &&
+		echo g >dir3/g &&
+		echo h >dir3/h &&
+		echo j >dirN/j &&
+		echo k >dirN/k &&
+		git add dir* &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		echo c  >dir1/c &&
+		echo yo >dir1/yo &&
+		echo f  >dir2/f &&
+		echo yo >dir2/yo &&
+		echo i  >dir3/i &&
+		echo yo >dir3/yo &&
+		echo l  >dirN/l &&
+		echo yo >dirN/yo &&
+		git add dir* &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv dir1 combined &&
+		git mv dir2/* combined/ &&
+		git mv dir3/* combined/ &&
+		git mv dirN/* combined/ &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success C_LOCALE_OUTPUT '9e-check: N-to-1 whammo' '
+	(
+		cd 9e &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 >out &&
+		grep "CONFLICT (implicit dir rename): Cannot map more than one path to combined/yo" out >error_line &&
+		grep -q dir1/yo error_line &&
+		grep -q dir2/yo error_line &&
+		grep -q dir3/yo error_line &&
+		grep -q dirN/yo error_line &&
+
+		git ls-files -s >out &&
+		test_line_count = 16 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 2 out &&
+
+		git rev-parse >actual \
+			:0:combined/a :0:combined/b :0:combined/c \
+			:0:combined/d :0:combined/e :0:combined/f \
+			:0:combined/g :0:combined/h :0:combined/i \
+			:0:combined/j :0:combined/k :0:combined/l &&
+		git rev-parse >expect \
+			 O:dir1/a      O:dir1/b      A:dir1/c \
+			 O:dir2/d      O:dir2/e      A:dir2/f \
+			 O:dir3/g      O:dir3/h      A:dir3/i \
+			 O:dirN/j      O:dirN/k      A:dirN/l &&
+		test_cmp expect actual &&
+
+		git rev-parse >actual \
+			:0:dir1/yo :0:dir2/yo :0:dir3/yo :0:dirN/yo &&
+		git rev-parse >expect \
+			 A:dir1/yo  A:dir2/yo  A:dir3/yo  A:dirN/yo &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 9f, Renamed directory that only contained immediate subdirs
+#   (Related to testcases 1e & 9g)
+#   Commit O: goal/{a,b}/$more_files
+#   Commit A: priority/{a,b}/$more_files
+#   Commit B: goal/{a,b}/$more_files, goal/c
+#   Expected: priority/{a,b}/$more_files, priority/c
+
+test_expect_success '9f-setup: Renamed directory that only contained immediate subdirs' '
+	test_create_repo 9f &&
+	(
+		cd 9f &&
+
+		mkdir -p goal/a &&
+		mkdir -p goal/b &&
+		echo foo >goal/a/foo &&
+		echo bar >goal/b/bar &&
+		echo baz >goal/b/baz &&
+		git add goal &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv goal/ priority &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo c >goal/c &&
+		git add goal/c &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '9f-check: Renamed directory that only contained immediate subdirs' '
+	(
+		cd 9f &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 4 out &&
+
+		git rev-parse >actual \
+			HEAD:priority/a/foo \
+			HEAD:priority/b/bar \
+			HEAD:priority/b/baz \
+			HEAD:priority/c &&
+		git rev-parse >expect \
+			O:goal/a/foo \
+			O:goal/b/bar \
+			O:goal/b/baz \
+			B:goal/c &&
+		test_cmp expect actual &&
+		test_must_fail git rev-parse HEAD:goal/c
+	)
+'
+
+# Testcase 9g, Renamed directory that only contained immediate subdirs, immediate subdirs renamed
+#   (Related to testcases 1e & 9f)
+#   Commit O: goal/{a,b}/$more_files
+#   Commit A: priority/{alpha,bravo}/$more_files
+#   Commit B: goal/{a,b}/$more_files, goal/c
+#   Expected: priority/{alpha,bravo}/$more_files, priority/c
+
+test_expect_success '9g-setup: Renamed directory that only contained immediate subdirs, immediate subdirs renamed' '
+	test_create_repo 9g &&
+	(
+		cd 9g &&
+
+		mkdir -p goal/a &&
+		mkdir -p goal/b &&
+		echo foo >goal/a/foo &&
+		echo bar >goal/b/bar &&
+		echo baz >goal/b/baz &&
+		git add goal &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		mkdir priority &&
+		git mv goal/a/ priority/alpha &&
+		git mv goal/b/ priority/beta &&
+		rmdir goal/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo c >goal/c &&
+		git add goal/c &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_failure '9g-check: Renamed directory that only contained immediate subdirs, immediate subdirs renamed' '
+	(
+		cd 9g &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 4 out &&
+
+		git rev-parse >actual \
+			HEAD:priority/alpha/foo \
+			HEAD:priority/beta/bar  \
+			HEAD:priority/beta/baz  \
+			HEAD:priority/c &&
+		git rev-parse >expect \
+			O:goal/a/foo \
+			O:goal/b/bar \
+			O:goal/b/baz \
+			B:goal/c &&
+		test_cmp expect actual &&
+		test_must_fail git rev-parse HEAD:goal/c
+	)
+'
+
+# Testcase 9h, Avoid implicit rename if involved as source on other side
+#   (Extremely closely related to testcase 3a)
+#   Commit O: z/{b,c,d_1}
+#   Commit A: z/{b,c,d_2}
+#   Commit B: y/{b,c}, x/d_1
+#   Expected: y/{b,c}, x/d_2
+#   NOTE: If we applied the z/ -> y/ rename to z/d, then we'd end up with
+#         a rename/rename(1to2) conflict (z/d -> y/d vs. x/d)
+test_expect_success '9h-setup: Avoid dir rename on merely modified path' '
+	test_create_repo 9h &&
+	(
+		cd 9h &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		printf "1\n2\n3\n4\n5\n6\n7\n8\nd\n" >z/d &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_tick &&
+		echo more >>z/d &&
+		git add z/d &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		mkdir y &&
+		mkdir x &&
+		git mv z/b y/ &&
+		git mv z/c y/ &&
+		git mv z/d x/ &&
+		rmdir z &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '9h-check: Avoid dir rename on merely modified path' '
+	(
+		cd 9h &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+
+		git rev-parse >actual \
+			HEAD:y/b HEAD:y/c HEAD:x/d &&
+		git rev-parse >expect \
+			O:z/b    O:z/c    A:z/d &&
+		test_cmp expect actual
+	)
+'
+
+###########################################################################
+# Rules suggested by section 9:
+#
+#   If the other side of history did a directory rename to a path that your
+#   side renamed away, then ignore that particular rename from the other
+#   side of history for any implicit directory renames.
+###########################################################################
+
+###########################################################################
+# SECTION 10: Handling untracked files
+#
+# unpack_trees(), upon which the recursive merge algorithm is based, aborts
+# the operation if untracked or dirty files would be deleted or overwritten
+# by the merge.  Unfortunately, unpack_trees() does not understand renames,
+# and if it doesn't abort, then it muddies up the working directory before
+# we even get to the point of detecting renames, so we need some special
+# handling, at least in the case of directory renames.
+###########################################################################
+
+# Testcase 10a, Overwrite untracked: normal rename/delete
+#   Commit O: z/{b,c_1}
+#   Commit A: z/b + untracked z/c + untracked z/d
+#   Commit B: z/{b,d_1}
+#   Expected: Aborted Merge +
+#       ERROR_MSG(untracked working tree files would be overwritten by merge)
+
+test_expect_success '10a-setup: Overwrite untracked with normal rename/delete' '
+	test_create_repo 10a &&
+	(
+		cd 10a &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git rm z/c &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv z/c z/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '10a-check: Overwrite untracked with normal rename/delete' '
+	(
+		cd 10a &&
+
+		git checkout A^0 &&
+		echo very >z/c &&
+		echo important >z/d &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep "The following untracked working tree files would be overwritten by merge" err &&
+
+		git ls-files -s >out &&
+		test_line_count = 1 out &&
+		git ls-files -o >out &&
+		test_line_count = 4 out &&
+
+		echo very >expect &&
+		test_cmp expect z/c &&
+
+		echo important >expect &&
+		test_cmp expect z/d &&
+
+		git rev-parse HEAD:z/b >actual &&
+		git rev-parse O:z/b >expect &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 10b, Overwrite untracked: dir rename + delete
+#   Commit O: z/{b,c_1}
+#   Commit A: y/b + untracked y/{c,d,e}
+#   Commit B: z/{b,d_1,e}
+#   Expected: Failed Merge; y/b + untracked y/c + untracked y/d on disk +
+#             z/c_1 -> z/d_1 rename recorded at stage 3 for y/d +
+#       ERROR_MSG(refusing to lose untracked file at 'y/d')
+
+test_expect_success '10b-setup: Overwrite untracked with dir rename + delete' '
+	test_create_repo 10b &&
+	(
+		cd 10b &&
+
+		mkdir z &&
+		echo b >z/b &&
+		echo c >z/c &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git rm z/c &&
+		git mv z/ y/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv z/c z/d &&
+		echo e >z/e &&
+		git add z/e &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '10b-check: Overwrite untracked with dir rename + delete' '
+	(
+		cd 10b &&
+
+		git checkout A^0 &&
+		echo very >y/c &&
+		echo important >y/d &&
+		echo contents >y/e &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep "CONFLICT (rename/delete).*Version B\^0 of y/d left in tree at y/d~B\^0" out &&
+		test_i18ngrep "Error: Refusing to lose untracked file at y/e; writing to y/e~B\^0 instead" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+		git ls-files -u >out &&
+		test_line_count = 2 out &&
+		git ls-files -o >out &&
+		test_line_count = 5 out &&
+
+		git rev-parse >actual \
+			:0:y/b :3:y/d :3:y/e &&
+		git rev-parse >expect \
+			O:z/b  O:z/c  B:z/e &&
+		test_cmp expect actual &&
+
+		echo very >expect &&
+		test_cmp expect y/c &&
+
+		echo important >expect &&
+		test_cmp expect y/d &&
+
+		echo contents >expect &&
+		test_cmp expect y/e
+	)
+'
+
+# Testcase 10c, Overwrite untracked: dir rename/rename(1to2)
+#   Commit O: z/{a,b}, x/{c,d}
+#   Commit A: y/{a,b}, w/c, x/d + different untracked y/c
+#   Commit B: z/{a,b,c}, x/d
+#   Expected: Failed Merge; y/{a,b} + x/d + untracked y/c +
+#             CONFLICT(rename/rename) x/c -> w/c vs y/c +
+#             y/c~B^0 +
+#             ERROR_MSG(Refusing to lose untracked file at y/c)
+
+test_expect_success '10c-setup: Overwrite untracked with dir rename/rename(1to2)' '
+	test_create_repo 10c &&
+	(
+		cd 10c &&
+
+		mkdir z x &&
+		echo a >z/a &&
+		echo b >z/b &&
+		echo c >x/c &&
+		echo d >x/d &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		mkdir w &&
+		git mv x/c w/c &&
+		git mv z/ y/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/c z/ &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '10c-check: Overwrite untracked with dir rename/rename(1to2)' '
+	(
+		cd 10c &&
+
+		git checkout A^0 &&
+		echo important >y/c &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		test_i18ngrep "Refusing to lose untracked file at y/c; adding as y/c~B\^0 instead" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 6 out &&
+		git ls-files -u >out &&
+		test_line_count = 3 out &&
+		git ls-files -o >out &&
+		test_line_count = 3 out &&
+
+		git rev-parse >actual \
+			:0:y/a :0:y/b :0:x/d :1:x/c :2:w/c :3:y/c &&
+		git rev-parse >expect \
+			 O:z/a  O:z/b  O:x/d  O:x/c  O:x/c  O:x/c &&
+		test_cmp expect actual &&
+
+		git hash-object y/c~B^0 >actual &&
+		git rev-parse O:x/c >expect &&
+		test_cmp expect actual &&
+
+		echo important >expect &&
+		test_cmp expect y/c
+	)
+'
+
+# Testcase 10d, Delete untracked w/ dir rename/rename(2to1)
+#   Commit O: z/{a,b,c_1},        x/{d,e,f_2}
+#   Commit A: y/{a,b},            x/{d,e,f_2,wham_1} + untracked y/wham
+#   Commit B: z/{a,b,c_1,wham_2}, y/{d,e}
+#   Expected: Failed Merge; y/{a,b,d,e} + untracked y/{wham,wham~B^0,wham~HEAD}+
+#             CONFLICT(rename/rename) z/c_1 vs x/f_2 -> y/wham
+#             ERROR_MSG(Refusing to lose untracked file at y/wham)
+
+test_expect_success '10d-setup: Delete untracked with dir rename/rename(2to1)' '
+	test_create_repo 10d &&
+	(
+		cd 10d &&
+
+		mkdir z x &&
+		echo a >z/a &&
+		echo b >z/b &&
+		echo c >z/c &&
+		echo d >x/d &&
+		echo e >x/e &&
+		echo f >x/f &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z/c x/wham &&
+		git mv z/ y/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/f z/wham &&
+		git mv x/ y/ &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '10d-check: Delete untracked with dir rename/rename(2to1)' '
+	(
+		cd 10d &&
+
+		git checkout A^0 &&
+		echo important >y/wham &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		test_i18ngrep "Refusing to lose untracked file at y/wham" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 6 out &&
+		git ls-files -u >out &&
+		test_line_count = 2 out &&
+		git ls-files -o >out &&
+		test_line_count = 4 out &&
+
+		git rev-parse >actual \
+			:0:y/a :0:y/b :0:y/d :0:y/e :2:y/wham :3:y/wham &&
+		git rev-parse >expect \
+			 O:z/a  O:z/b  O:x/d  O:x/e  O:z/c     O:x/f &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse :1:y/wham &&
+
+		echo important >expect &&
+		test_cmp expect y/wham &&
+
+		git hash-object >actual \
+			y/wham~B^0 y/wham~HEAD &&
+		git rev-parse >expect \
+			O:x/f      O:z/c &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 10e, Does git complain about untracked file that's not in the way?
+#   Commit O: z/{a,b}
+#   Commit A: y/{a,b} + untracked z/c
+#   Commit B: z/{a,b,c}
+#   Expected: y/{a,b,c} + untracked z/c
+
+test_expect_success '10e-setup: Does git complain about untracked file that is not really in the way?' '
+	test_create_repo 10e &&
+	(
+		cd 10e &&
+
+		mkdir z &&
+		echo a >z/a &&
+		echo b >z/b &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z/ y/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo c >z/c &&
+		git add z/c &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_failure '10e-check: Does git complain about untracked file that is not really in the way?' '
+	(
+		cd 10e &&
+
+		git checkout A^0 &&
+		mkdir z &&
+		echo random >z/c &&
+
+		git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep ! "following untracked working tree files would be overwritten by merge" err &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 3 out &&
+
+		git rev-parse >actual \
+			:0:y/a :0:y/b :0:y/c &&
+		git rev-parse >expect \
+			 O:z/a  O:z/b  B:z/c &&
+		test_cmp expect actual &&
+
+		echo random >expect &&
+		test_cmp expect z/c
+	)
+'
+
+###########################################################################
+# SECTION 11: Handling dirty (not up-to-date) files
+#
+# unpack_trees(), upon which the recursive merge algorithm is based, aborts
+# the operation if untracked or dirty files would be deleted or overwritten
+# by the merge.  Unfortunately, unpack_trees() does not understand renames,
+# and if it doesn't abort, then it muddies up the working directory before
+# we even get to the point of detecting renames, so we need some special
+# handling.  This was true even of normal renames, but there are additional
+# codepaths that need special handling with directory renames.  Add
+# testcases for both renamed-by-directory-rename-detection and standard
+# rename cases.
+###########################################################################
+
+# Testcase 11a, Avoid losing dirty contents with simple rename
+#   Commit O: z/{a,b_v1},
+#   Commit A: z/{a,c_v1}, and z/c_v1 has uncommitted mods
+#   Commit B: z/{a,b_v2}
+#   Expected: ERROR_MSG(Refusing to lose dirty file at z/c) +
+#             z/a, staged version of z/c has sha1sum matching B:z/b_v2,
+#             z/c~HEAD with contents of B:z/b_v2,
+#             z/c with uncommitted mods on top of A:z/c_v1
+
+test_expect_success '11a-setup: Avoid losing dirty contents with simple rename' '
+	test_create_repo 11a &&
+	(
+		cd 11a &&
+
+		mkdir z &&
+		echo a >z/a &&
+		test_seq 1 10 >z/b &&
+		git add z &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z/b z/c &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo 11 >>z/b &&
+		git add z/b &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '11a-check: Avoid losing dirty contents with simple rename' '
+	(
+		cd 11a &&
+
+		git checkout A^0 &&
+		echo stuff >>z/c &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
+
+		test_seq 1 10 >expected &&
+		echo stuff >>expected &&
+		test_cmp expected z/c &&
+
+		git ls-files -s >out &&
+		test_line_count = 2 out &&
+		git ls-files -u >out &&
+		test_line_count = 1 out &&
+		git ls-files -o >out &&
+		test_line_count = 4 out &&
+
+		git rev-parse >actual \
+			:0:z/a :2:z/c &&
+		git rev-parse >expect \
+			 O:z/a  B:z/b &&
+		test_cmp expect actual &&
+
+		git hash-object z/c~HEAD >actual &&
+		git rev-parse B:z/b >expect &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 11b, Avoid losing dirty file involved in directory rename
+#   Commit O: z/a,         x/{b,c_v1}
+#   Commit A: z/{a,c_v1},  x/b,       and z/c_v1 has uncommitted mods
+#   Commit B: y/a,         x/{b,c_v2}
+#   Expected: y/{a,c_v2}, x/b, z/c_v1 with uncommitted mods untracked,
+#             ERROR_MSG(Refusing to lose dirty file at z/c)
+
+
+test_expect_success '11b-setup: Avoid losing dirty file involved in directory rename' '
+	test_create_repo 11b &&
+	(
+		cd 11b &&
+
+		mkdir z x &&
+		echo a >z/a &&
+		echo b >x/b &&
+		test_seq 1 10 >x/c &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv x/c z/c &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv z y &&
+		echo 11 >>x/c &&
+		git add x/c &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '11b-check: Avoid losing dirty file involved in directory rename' '
+	(
+		cd 11b &&
+
+		git checkout A^0 &&
+		echo stuff >>z/c &&
+
+		git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
+
+		grep -q stuff z/c &&
+		test_seq 1 10 >expected &&
+		echo stuff >>expected &&
+		test_cmp expected z/c &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -m >out &&
+		test_line_count = 0 out &&
+		git ls-files -o >out &&
+		test_line_count = 4 out &&
+
+		git rev-parse >actual \
+			:0:x/b :0:y/a :0:y/c &&
+		git rev-parse >expect \
+			 O:x/b  O:z/a  B:x/c &&
+		test_cmp expect actual &&
+
+		git hash-object y/c >actual &&
+		git rev-parse B:x/c >expect &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 11c, Avoid losing not-up-to-date with rename + D/F conflict
+#   Commit O: y/a,         x/{b,c_v1}
+#   Commit A: y/{a,c_v1},  x/b,       and y/c_v1 has uncommitted mods
+#   Commit B: y/{a,c/d},   x/{b,c_v2}
+#   Expected: Abort_msg("following files would be overwritten by merge") +
+#             y/c left untouched (still has uncommitted mods)
+
+test_expect_success '11c-setup: Avoid losing not-uptodate with rename + D/F conflict' '
+	test_create_repo 11c &&
+	(
+		cd 11c &&
+
+		mkdir y x &&
+		echo a >y/a &&
+		echo b >x/b &&
+		test_seq 1 10 >x/c &&
+		git add y x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv x/c y/c &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		mkdir y/c &&
+		echo d >y/c/d &&
+		echo 11 >>x/c &&
+		git add x/c y/c/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '11c-check: Avoid losing not-uptodate with rename + D/F conflict' '
+	(
+		cd 11c &&
+
+		git checkout A^0 &&
+		echo stuff >>y/c &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep "following files would be overwritten by merge" err &&
+
+		grep -q stuff y/c &&
+		test_seq 1 10 >expected &&
+		echo stuff >>expected &&
+		test_cmp expected y/c &&
+
+		git ls-files -s >out &&
+		test_line_count = 3 out &&
+		git ls-files -u >out &&
+		test_line_count = 0 out &&
+		git ls-files -m >out &&
+		test_line_count = 1 out &&
+		git ls-files -o >out &&
+		test_line_count = 3 out
+	)
+'
+
+# Testcase 11d, Avoid losing not-up-to-date with rename + D/F conflict
+#   Commit O: z/a,         x/{b,c_v1}
+#   Commit A: z/{a,c_v1},  x/b,       and z/c_v1 has uncommitted mods
+#   Commit B: y/{a,c/d},   x/{b,c_v2}
+#   Expected: D/F: y/c_v2 vs y/c/d) +
+#             Warning_Msg("Refusing to lose dirty file at z/c) +
+#             y/{a,c~HEAD,c/d}, x/b, now-untracked z/c_v1 with uncommitted mods
+
+test_expect_success '11d-setup: Avoid losing not-uptodate with rename + D/F conflict' '
+	test_create_repo 11d &&
+	(
+		cd 11d &&
+
+		mkdir z x &&
+		echo a >z/a &&
+		echo b >x/b &&
+		test_seq 1 10 >x/c &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv x/c z/c &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv z y &&
+		mkdir y/c &&
+		echo d >y/c/d &&
+		echo 11 >>x/c &&
+		git add x/c y/c/d &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '11d-check: Avoid losing not-uptodate with rename + D/F conflict' '
+	(
+		cd 11d &&
+
+		git checkout A^0 &&
+		echo stuff >>z/c &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep "Refusing to lose dirty file at z/c" out &&
+
+		grep -q stuff z/c &&
+		test_seq 1 10 >expected &&
+		echo stuff >>expected &&
+		test_cmp expected z/c
+
+		git ls-files -s >out &&
+		test_line_count = 4 out &&
+		git ls-files -u >out &&
+		test_line_count = 1 out &&
+		git ls-files -o >out &&
+		test_line_count = 5 out &&
+
+		git rev-parse >actual \
+			:0:x/b :0:y/a :0:y/c/d :3:y/c &&
+		git rev-parse >expect \
+			 O:x/b  O:z/a  B:y/c/d  B:x/c &&
+		test_cmp expect actual &&
+
+		git hash-object y/c~HEAD >actual &&
+		git rev-parse B:x/c >expect &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 11e, Avoid deleting not-up-to-date with dir rename/rename(1to2)/add
+#   Commit O: z/{a,b},      x/{c_1,d}
+#   Commit A: y/{a,b,c_2},  x/d, w/c_1, and y/c_2 has uncommitted mods
+#   Commit B: z/{a,b,c_1},  x/d
+#   Expected: Failed Merge; y/{a,b} + x/d +
+#             CONFLICT(rename/rename) x/c_1 -> w/c_1 vs y/c_1 +
+#             ERROR_MSG(Refusing to lose dirty file at y/c)
+#             y/c~B^0 has O:x/c_1 contents
+#             y/c~HEAD has A:y/c_2 contents
+#             y/c has dirty file from before merge
+
+test_expect_success '11e-setup: Avoid deleting not-uptodate with dir rename/rename(1to2)/add' '
+	test_create_repo 11e &&
+	(
+		cd 11e &&
+
+		mkdir z x &&
+		echo a >z/a &&
+		echo b >z/b &&
+		echo c >x/c &&
+		echo d >x/d &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z/ y/ &&
+		echo different >y/c &&
+		mkdir w &&
+		git mv x/c w/ &&
+		git add y/c &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/c z/ &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '11e-check: Avoid deleting not-uptodate with dir rename/rename(1to2)/add' '
+	(
+		cd 11e &&
+
+		git checkout A^0 &&
+		echo mods >>y/c &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		test_i18ngrep "Refusing to lose dirty file at y/c" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 7 out &&
+		git ls-files -u >out &&
+		test_line_count = 4 out &&
+		git ls-files -o >out &&
+		test_line_count = 4 out &&
+
+		echo different >expected &&
+		echo mods >>expected &&
+		test_cmp expected y/c &&
+
+		git rev-parse >actual \
+			:0:y/a :0:y/b :0:x/d :1:x/c :2:w/c :2:y/c :3:y/c &&
+		git rev-parse >expect \
+			 O:z/a  O:z/b  O:x/d  O:x/c  O:x/c  A:y/c  O:x/c &&
+		test_cmp expect actual &&
+
+		git hash-object >actual \
+			y/c~B^0 y/c~HEAD &&
+		git rev-parse >expect \
+			O:x/c   A:y/c &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 11f, Avoid deleting not-up-to-date w/ dir rename/rename(2to1)
+#   Commit O: z/{a,b},        x/{c_1,d_2}
+#   Commit A: y/{a,b,wham_1}, x/d_2, except y/wham has uncommitted mods
+#   Commit B: z/{a,b,wham_2}, x/c_1
+#   Expected: Failed Merge; y/{a,b} + untracked y/{wham~B^0,wham~B^HEAD} +
+#             y/wham with dirty changes from before merge +
+#             CONFLICT(rename/rename) x/c vs x/d -> y/wham
+#             ERROR_MSG(Refusing to lose dirty file at y/wham)
+
+test_expect_success '11f-setup: Avoid deleting not-uptodate with dir rename/rename(2to1)' '
+	test_create_repo 11f &&
+	(
+		cd 11f &&
+
+		mkdir z x &&
+		echo a >z/a &&
+		echo b >z/b &&
+		test_seq 1 10 >x/c &&
+		echo d >x/d &&
+		git add z x &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv z/ y/ &&
+		git mv x/c y/wham &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv x/d z/wham &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '11f-check: Avoid deleting not-uptodate with dir rename/rename(2to1)' '
+	(
+		cd 11f &&
+
+		git checkout A^0 &&
+		echo important >>y/wham &&
+
+		test_must_fail git merge -s recursive B^0 >out 2>err &&
+		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		test_i18ngrep "Refusing to lose dirty file at y/wham" out &&
+
+		git ls-files -s >out &&
+		test_line_count = 4 out &&
+		git ls-files -u >out &&
+		test_line_count = 2 out &&
+		git ls-files -o >out &&
+		test_line_count = 4 out &&
+
+		test_seq 1 10 >expected &&
+		echo important >>expected &&
+		test_cmp expected y/wham &&
+
+		test_must_fail git rev-parse :1:y/wham &&
+		git hash-object >actual \
+			y/wham~B^0 y/wham~HEAD &&
+		git rev-parse >expect \
+			O:x/d      O:x/c &&
+		test_cmp expect actual &&
+
+		git rev-parse >actual \
+			:0:y/a :0:y/b :2:y/wham :3:y/wham &&
+		git rev-parse >expect \
+			 O:z/a  O:z/b  O:x/c     O:x/d &&
+		test_cmp expect actual
+	)
+'
+
+###########################################################################
+# SECTION 12: Everything else
+#
+# Tests suggested by others.  Tests added after implementation completed
+# and submitted.  Grab bag.
+###########################################################################
+
+# Testcase 12a, Moving one directory hierarchy into another
+#   (Related to testcase 9a)
+#   Commit O: node1/{leaf1,leaf2}, node2/{leaf3,leaf4}
+#   Commit A: node1/{leaf1,leaf2,node2/{leaf3,leaf4}}
+#   Commit B: node1/{leaf1,leaf2,leaf5}, node2/{leaf3,leaf4,leaf6}
+#   Expected: node1/{leaf1,leaf2,leaf5,node2/{leaf3,leaf4,leaf6}}
+
+test_expect_success '12a-setup: Moving one directory hierarchy into another' '
+	test_create_repo 12a &&
+	(
+		cd 12a &&
+
+		mkdir -p node1 node2 &&
+		echo leaf1 >node1/leaf1 &&
+		echo leaf2 >node1/leaf2 &&
+		echo leaf3 >node2/leaf3 &&
+		echo leaf4 >node2/leaf4 &&
+		git add node1 node2 &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv node2/ node1/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo leaf5 >node1/leaf5 &&
+		echo leaf6 >node2/leaf6 &&
+		git add node1 node2 &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '12a-check: Moving one directory hierarchy into another' '
+	(
+		cd 12a &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 6 out &&
+
+		git rev-parse >actual \
+			HEAD:node1/leaf1 HEAD:node1/leaf2 HEAD:node1/leaf5 \
+			HEAD:node1/node2/leaf3 \
+			HEAD:node1/node2/leaf4 \
+			HEAD:node1/node2/leaf6 &&
+		git rev-parse >expect \
+			O:node1/leaf1    O:node1/leaf2    B:node1/leaf5 \
+			O:node2/leaf3 \
+			O:node2/leaf4 \
+			B:node2/leaf6 &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 12b, Moving two directory hierarchies into each other
+#   (Related to testcases 1c and 12c)
+#   Commit O: node1/{leaf1, leaf2}, node2/{leaf3, leaf4}
+#   Commit A: node1/{leaf1, leaf2, node2/{leaf3, leaf4}}
+#   Commit B: node2/{leaf3, leaf4, node1/{leaf1, leaf2}}
+#   Expected: node1/node2/node1/{leaf1, leaf2},
+#             node2/node1/node2/{leaf3, leaf4}
+#   NOTE: Without directory renames, we would expect
+#                   node2/node1/{leaf1, leaf2},
+#                   node1/node2/{leaf3, leaf4}
+#         with directory rename detection, we note that
+#             commit A renames node2/ -> node1/node2/
+#             commit B renames node1/ -> node2/node1/
+#         therefore, applying those directory renames to the initial result
+#         (making all four paths experience a transitive renaming), yields
+#         the expected result.
+#
+#         You may ask, is it weird to have two directories rename each other?
+#         To which, I can do no more than shrug my shoulders and say that
+#         even simple rules give weird results when given weird inputs.
+
+test_expect_success '12b-setup: Moving one directory hierarchy into another' '
+	test_create_repo 12b &&
+	(
+		cd 12b &&
+
+		mkdir -p node1 node2 &&
+		echo leaf1 >node1/leaf1 &&
+		echo leaf2 >node1/leaf2 &&
+		echo leaf3 >node2/leaf3 &&
+		echo leaf4 >node2/leaf4 &&
+		git add node1 node2 &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv node2/ node1/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv node1/ node2/ &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '12b-check: Moving one directory hierarchy into another' '
+	(
+		cd 12b &&
+
+		git checkout A^0 &&
+
+		git merge -s recursive B^0 &&
+
+		git ls-files -s >out &&
+		test_line_count = 4 out &&
+
+		git rev-parse >actual \
+			HEAD:node1/node2/node1/leaf1 \
+			HEAD:node1/node2/node1/leaf2 \
+			HEAD:node2/node1/node2/leaf3 \
+			HEAD:node2/node1/node2/leaf4 &&
+		git rev-parse >expect \
+			O:node1/leaf1 \
+			O:node1/leaf2 \
+			O:node2/leaf3 \
+			O:node2/leaf4 &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 12c, Moving two directory hierarchies into each other w/ content merge
+#   (Related to testcase 12b)
+#   Commit O: node1/{       leaf1_1, leaf2_1}, node2/{leaf3_1, leaf4_1}
+#   Commit A: node1/{       leaf1_2, leaf2_2,  node2/{leaf3_2, leaf4_2}}
+#   Commit B: node2/{node1/{leaf1_3, leaf2_3},        leaf3_3, leaf4_3}
+#   Expected: Content merge conflicts for each of:
+#               node1/node2/node1/{leaf1, leaf2},
+#               node2/node1/node2/{leaf3, leaf4}
+#   NOTE: This is *exactly* like 12c, except that every path is modified on
+#         each side of the merge.
+
+test_expect_success '12c-setup: Moving one directory hierarchy into another w/ content merge' '
+	test_create_repo 12c &&
+	(
+		cd 12c &&
+
+		mkdir -p node1 node2 &&
+		printf "1\n2\n3\n4\n5\n6\n7\n8\nleaf1\n" >node1/leaf1 &&
+		printf "1\n2\n3\n4\n5\n6\n7\n8\nleaf2\n" >node1/leaf2 &&
+		printf "1\n2\n3\n4\n5\n6\n7\n8\nleaf3\n" >node2/leaf3 &&
+		printf "1\n2\n3\n4\n5\n6\n7\n8\nleaf4\n" >node2/leaf4 &&
+		git add node1 node2 &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv node2/ node1/ &&
+		for i in `git ls-files`; do echo side A >>$i; done &&
+		git add -u &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv node1/ node2/ &&
+		for i in `git ls-files`; do echo side B >>$i; done &&
+		git add -u &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '12c-check: Moving one directory hierarchy into another w/ content merge' '
+	(
+		cd 12c &&
+
+		git checkout A^0 &&
+
+		test_must_fail git merge -s recursive B^0 &&
+
+		git ls-files -u >out &&
+		test_line_count = 12 out &&
+
+		git rev-parse >actual \
+			:1:node1/node2/node1/leaf1 \
+			:1:node1/node2/node1/leaf2 \
+			:1:node2/node1/node2/leaf3 \
+			:1:node2/node1/node2/leaf4 \
+			:2:node1/node2/node1/leaf1 \
+			:2:node1/node2/node1/leaf2 \
+			:2:node2/node1/node2/leaf3 \
+			:2:node2/node1/node2/leaf4 \
+			:3:node1/node2/node1/leaf1 \
+			:3:node1/node2/node1/leaf2 \
+			:3:node2/node1/node2/leaf3 \
+			:3:node2/node1/node2/leaf4 &&
+		git rev-parse >expect \
+			O:node1/leaf1 \
+			O:node1/leaf2 \
+			O:node2/leaf3 \
+			O:node2/leaf4 \
+			A:node1/leaf1 \
+			A:node1/leaf2 \
+			A:node1/node2/leaf3 \
+			A:node1/node2/leaf4 \
+			B:node2/node1/leaf1 \
+			B:node2/node1/leaf2 \
+			B:node2/leaf3 \
+			B:node2/leaf4 &&
+		test_cmp expect actual
+	)
+'
+
+test_done
diff --git a/t/t6046-merge-skip-unneeded-updates.sh b/t/t6046-merge-skip-unneeded-updates.sh
new file mode 100755
index 0000000..fcefffc
--- /dev/null
+++ b/t/t6046-merge-skip-unneeded-updates.sh
@@ -0,0 +1,761 @@
+#!/bin/sh
+
+test_description="merge cases"
+
+# The setup for all of them, pictorially, is:
+#
+#      A
+#      o
+#     / \
+#  O o   ?
+#     \ /
+#      o
+#      B
+#
+# To help make it easier to follow the flow of tests, they have been
+# divided into sections and each test will start with a quick explanation
+# of what commits O, A, and B contain.
+#
+# Notation:
+#    z/{b,c}   means  files z/b and z/c both exist
+#    x/d_1     means  file x/d exists with content d1.  (Purpose of the
+#                     underscore notation is to differentiate different
+#                     files that might be renamed into each other's paths.)
+
+. ./test-lib.sh
+
+
+###########################################################################
+# SECTION 1: Cases involving no renames (one side has subset of changes of
+#            the other side)
+###########################################################################
+
+# Testcase 1a, Changes on A, subset of changes on B
+#   Commit O: b_1
+#   Commit A: b_2
+#   Commit B: b_3
+#   Expected: b_2
+
+test_expect_success '1a-setup: Modify(A)/Modify(B), change on B subset of A' '
+	test_create_repo 1a &&
+	(
+		cd 1a &&
+
+		test_write_lines 1 2 3 4 5 6 7 8 9 10 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_write_lines 1 2 3 4 5 5.5 6 7 8 9 10 10.5 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		test_write_lines 1 2 3 4 5 5.5 6 7 8 9 10 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '1a-check-L: Modify(A)/Modify(B), change on B subset of A' '
+	test_when_finished "git -C 1a reset --hard" &&
+	test_when_finished "git -C 1a clean -fd" &&
+	(
+		cd 1a &&
+
+		git checkout A^0 &&
+
+		test-tool chmtime =31337 b &&
+		test-tool chmtime -v +0 b >expected-mtime &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep "Skipped b" out &&
+		test_must_be_empty err &&
+
+		test-tool chmtime -v +0 b >actual-mtime &&
+		test_cmp expected-mtime actual-mtime &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 1 index_files &&
+
+		git rev-parse >actual HEAD:b &&
+		git rev-parse >expect A:b &&
+		test_cmp expect actual &&
+
+		git hash-object b   >actual &&
+		git rev-parse   A:b >expect &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success '1a-check-R: Modify(A)/Modify(B), change on B subset of A' '
+	test_when_finished "git -C 1a reset --hard" &&
+	test_when_finished "git -C 1a clean -fd" &&
+	(
+		cd 1a &&
+
+		git checkout B^0 &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive A^0 >out 2>err &&
+
+		test_i18ngrep "Auto-merging b" out &&
+		test_must_be_empty err &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 1 index_files &&
+
+		git rev-parse >actual HEAD:b &&
+		git rev-parse >expect A:b &&
+		test_cmp expect actual &&
+
+		git hash-object b   >actual &&
+		git rev-parse   A:b >expect &&
+		test_cmp expect actual
+	)
+'
+
+
+###########################################################################
+# SECTION 2: Cases involving basic renames
+###########################################################################
+
+# Testcase 2a, Changes on A, rename on B
+#   Commit O: b_1
+#   Commit A: b_2
+#   Commit B: c_1
+#   Expected: c_2
+
+test_expect_success '2a-setup: Modify(A)/rename(B)' '
+	test_create_repo 2a &&
+	(
+		cd 2a &&
+
+		test_seq 1 10 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_seq 1 11 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv b c &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '2a-check-L: Modify/rename, merge into modify side' '
+	test_when_finished "git -C 2a reset --hard" &&
+	test_when_finished "git -C 2a clean -fd" &&
+	(
+		cd 2a &&
+
+		git checkout A^0 &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep ! "Skipped c" out &&
+		test_must_be_empty err &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 1 index_files &&
+
+		git rev-parse >actual HEAD:c &&
+		git rev-parse >expect A:b &&
+		test_cmp expect actual &&
+
+		git hash-object c   >actual &&
+		git rev-parse   A:b >expect &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse HEAD:b &&
+		test_path_is_missing b
+	)
+'
+
+test_expect_success '2a-check-R: Modify/rename, merge into rename side' '
+	test_when_finished "git -C 2a reset --hard" &&
+	test_when_finished "git -C 2a clean -fd" &&
+	(
+		cd 2a &&
+
+		git checkout B^0 &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive A^0 >out 2>err &&
+
+		test_i18ngrep ! "Skipped c" out &&
+		test_must_be_empty err &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 1 index_files &&
+
+		git rev-parse >actual HEAD:c &&
+		git rev-parse >expect A:b &&
+		test_cmp expect actual &&
+
+		git hash-object c   >actual &&
+		git rev-parse   A:b >expect &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse HEAD:b &&
+		test_path_is_missing b
+	)
+'
+
+# Testcase 2b, Changed and renamed on A, subset of changes on B
+#   Commit O: b_1
+#   Commit A: c_2
+#   Commit B: b_3
+#   Expected: c_2
+
+test_expect_success '2b-setup: Rename+Mod(A)/Mod(B), B mods subset of A' '
+	test_create_repo 2b &&
+	(
+		cd 2b &&
+
+		test_write_lines 1 2 3 4 5 6 7 8 9 10 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_write_lines 1 2 3 4 5 5.5 6 7 8 9 10 10.5 >b &&
+		git add b &&
+		git mv b c &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		test_write_lines 1 2 3 4 5 5.5 6 7 8 9 10 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '2b-check-L: Rename+Mod(A)/Mod(B), B mods subset of A' '
+	test_when_finished "git -C 2b reset --hard" &&
+	test_when_finished "git -C 2b clean -fd" &&
+	(
+		cd 2b &&
+
+		git checkout A^0 &&
+
+		test-tool chmtime =31337 c &&
+		test-tool chmtime -v +0 c >expected-mtime &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep "Skipped c" out &&
+		test_must_be_empty err &&
+
+		test-tool chmtime -v +0 c >actual-mtime &&
+		test_cmp expected-mtime actual-mtime &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 1 index_files &&
+
+		git rev-parse >actual HEAD:c &&
+		git rev-parse >expect A:c &&
+		test_cmp expect actual &&
+
+		git hash-object c   >actual &&
+		git rev-parse   A:c >expect &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse HEAD:b &&
+		test_path_is_missing b
+	)
+'
+
+test_expect_success '2b-check-R: Rename+Mod(A)/Mod(B), B mods subset of A' '
+	test_when_finished "git -C 2b reset --hard" &&
+	test_when_finished "git -C 2b clean -fd" &&
+	(
+		cd 2b &&
+
+		git checkout B^0 &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive A^0 >out 2>err &&
+
+		test_i18ngrep "Auto-merging c" out &&
+		test_must_be_empty err &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 1 index_files &&
+
+		git rev-parse >actual HEAD:c &&
+		git rev-parse >expect A:c &&
+		test_cmp expect actual &&
+
+		git hash-object c   >actual &&
+		git rev-parse   A:c >expect &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse HEAD:b &&
+		test_path_is_missing b
+	)
+'
+
+# Testcase 2c, Changes on A, rename on B
+#   Commit O: b_1
+#   Commit A: b_2, c_3
+#   Commit B: c_1
+#   Expected: rename/add conflict c_2 vs c_3
+#
+#   NOTE: Since A modified b_1->b_2, and B renamed b_1->c_1, the threeway
+#         merge of those files should result in c_2.  We then should have a
+#         rename/add conflict between c_2 and c_3.  However, if we note in
+#         merge_content() that A had the right contents (b_2 has same
+#         contents as c_2, just at a different name), and that A had the
+#         right path present (c_3 existed) and thus decides that it can
+#         skip the update, then we're in trouble.  This test verifies we do
+#         not make that particular mistake.
+
+test_expect_success '2c-setup: Modify b & add c VS rename b->c' '
+	test_create_repo 2c &&
+	(
+		cd 2c &&
+
+		test_seq 1 10 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_seq 1 11 >b &&
+		echo whatever >c &&
+		git add b c &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv b c &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '2c-check: Modify b & add c VS rename b->c' '
+	(
+		cd 2c &&
+
+		git checkout A^0 &&
+
+		GIT_MERGE_VERBOSITY=3 test_must_fail git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep "CONFLICT (rename/add): Rename b->c" out &&
+		test_i18ngrep ! "Skipped c" out &&
+		test_must_be_empty err
+
+		# FIXME: rename/add conflicts are horribly broken right now;
+		# when I get back to my patch series fixing it and
+		# rename/rename(2to1) conflicts to bring them in line with
+		# how add/add conflicts behave, then checks like the below
+		# could be added.  But that patch series is waiting until
+		# the rename-directory-detection series lands, which this
+		# is part of.  And in the mean time, I do not want to further
+		# enforce broken behavior.  So for now, the main test is the
+		# one above that err is an empty file.
+
+		#git ls-files -s >index_files &&
+		#test_line_count = 2 index_files &&
+
+		#git rev-parse >actual :2:c :3:c &&
+		#git rev-parse >expect A:b  A:c  &&
+		#test_cmp expect actual &&
+
+		#git cat-file -p A:b >>merged &&
+		#git cat-file -p A:c >>merge-me &&
+		#>empty &&
+		#test_must_fail git merge-file \
+		#	-L "Temporary merge branch 1" \
+		#	-L "" \
+		#	-L "Temporary merge branch 2" \
+		#	merged empty merge-me &&
+		#sed -e "s/^\([<=>]\)/\1\1\1/" merged >merged-internal &&
+
+		#git hash-object c               >actual &&
+		#git hash-object merged-internal >expect &&
+		#test_cmp expect actual &&
+
+		#test_path_is_missing b
+	)
+'
+
+
+###########################################################################
+# SECTION 3: Cases involving directory renames
+#
+# NOTE:
+#   Directory renames only apply when one side renames a directory, and the
+#   other side adds or renames a path into that directory.  Applying the
+#   directory rename to that new path creates a new pathname that didn't
+#   exist on either side of history.  Thus, it is impossible for the
+#   merge contents to already be at the right path, so all of these checks
+#   exist just to make sure that updates are not skipped.
+###########################################################################
+
+# Testcase 3a, Change + rename into dir foo on A, dir rename foo->bar on B
+#   Commit O: bq_1, foo/whatever
+#   Commit A: foo/{bq_2, whatever}
+#   Commit B: bq_1, bar/whatever
+#   Expected: bar/{bq_2, whatever}
+
+test_expect_success '3a-setup: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
+	test_create_repo 3a &&
+	(
+		cd 3a &&
+
+		mkdir foo &&
+		test_seq 1 10 >bq &&
+		test_write_lines a b c d e f g h i j k >foo/whatever &&
+		git add bq foo/whatever &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_seq 1 11 >bq &&
+		git add bq &&
+		git mv bq foo/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		git mv foo/ bar/ &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '3a-check-L: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
+	test_when_finished "git -C 3a reset --hard" &&
+	test_when_finished "git -C 3a clean -fd" &&
+	(
+		cd 3a &&
+
+		git checkout A^0 &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep ! "Skipped bar/bq" out &&
+		test_must_be_empty err &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 2 index_files &&
+
+		git rev-parse >actual HEAD:bar/bq HEAD:bar/whatever &&
+		git rev-parse >expect A:foo/bq    A:foo/whatever &&
+		test_cmp expect actual &&
+
+		git hash-object bar/bq   bar/whatever   >actual &&
+		git rev-parse   A:foo/bq A:foo/whatever >expect &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse HEAD:bq HEAD:foo/bq &&
+		test_path_is_missing bq foo/bq foo/whatever
+	)
+'
+
+test_expect_success '3a-check-R: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
+	test_when_finished "git -C 3a reset --hard" &&
+	test_when_finished "git -C 3a clean -fd" &&
+	(
+		cd 3a &&
+
+		git checkout B^0 &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive A^0 >out 2>err &&
+
+		test_i18ngrep ! "Skipped bar/bq" out &&
+		test_must_be_empty err &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 2 index_files &&
+
+		git rev-parse >actual HEAD:bar/bq HEAD:bar/whatever &&
+		git rev-parse >expect A:foo/bq    A:foo/whatever &&
+		test_cmp expect actual &&
+
+		git hash-object bar/bq   bar/whatever   >actual &&
+		git rev-parse   A:foo/bq A:foo/whatever >expect &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse HEAD:bq HEAD:foo/bq &&
+		test_path_is_missing bq foo/bq foo/whatever
+	)
+'
+
+# Testcase 3b, rename into dir foo on A, dir rename foo->bar + change on B
+#   Commit O: bq_1, foo/whatever
+#   Commit A: foo/{bq_1, whatever}
+#   Commit B: bq_2, bar/whatever
+#   Expected: bar/{bq_2, whatever}
+
+test_expect_success '3b-setup: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
+	test_create_repo 3b &&
+	(
+		cd 3b &&
+
+		mkdir foo &&
+		test_seq 1 10 >bq &&
+		test_write_lines a b c d e f g h i j k >foo/whatever &&
+		git add bq foo/whatever &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv bq foo/ &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		test_seq 1 11 >bq &&
+		git add bq &&
+		git mv foo/ bar/ &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '3b-check-L: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
+	test_when_finished "git -C 3b reset --hard" &&
+	test_when_finished "git -C 3b clean -fd" &&
+	(
+		cd 3b &&
+
+		git checkout A^0 &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep ! "Skipped bar/bq" out &&
+		test_must_be_empty err &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 2 index_files &&
+
+		git rev-parse >actual HEAD:bar/bq HEAD:bar/whatever &&
+		git rev-parse >expect B:bq        A:foo/whatever &&
+		test_cmp expect actual &&
+
+		git hash-object bar/bq bar/whatever   >actual &&
+		git rev-parse   B:bq   A:foo/whatever >expect &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse HEAD:bq HEAD:foo/bq &&
+		test_path_is_missing bq foo/bq foo/whatever
+	)
+'
+
+test_expect_success '3b-check-R: bq_1->foo/bq_2 on A, foo/->bar/ on B' '
+	test_when_finished "git -C 3b reset --hard" &&
+	test_when_finished "git -C 3b clean -fd" &&
+	(
+		cd 3b &&
+
+		git checkout B^0 &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive A^0 >out 2>err &&
+
+		test_i18ngrep ! "Skipped bar/bq" out &&
+		test_must_be_empty err &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 2 index_files &&
+
+		git rev-parse >actual HEAD:bar/bq HEAD:bar/whatever &&
+		git rev-parse >expect B:bq        A:foo/whatever &&
+		test_cmp expect actual &&
+
+		git hash-object bar/bq bar/whatever   >actual &&
+		git rev-parse   B:bq   A:foo/whatever >expect &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse HEAD:bq HEAD:foo/bq &&
+		test_path_is_missing bq foo/bq foo/whatever
+	)
+'
+
+###########################################################################
+# SECTION 4: Cases involving dirty changes
+###########################################################################
+
+# Testcase 4a, Changed on A, subset of changes on B, locally modified
+#   Commit O: b_1
+#   Commit A: b_2
+#   Commit B: b_3
+#   Working copy: b_4
+#   Expected: b_2 for merge, b_4 in working copy
+
+test_expect_success '4a-setup: Change on A, change on B subset of A, dirty mods present' '
+	test_create_repo 4a &&
+	(
+		cd 4a &&
+
+		test_write_lines 1 2 3 4 5 6 7 8 9 10 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_write_lines 1 2 3 4 5 5.5 6 7 8 9 10 10.5 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		test_write_lines 1 2 3 4 5 5.5 6 7 8 9 10 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+# NOTE: For as long as we continue using unpack_trees() without index_only
+#   set to true, it will error out on a case like this claiming the the locally
+#   modified file would be overwritten by the merge.  Getting this testcase
+#   correct requires doing the merge in-memory first, then realizing that no
+#   updates to the file are necessary, and thus that we can just leave the path
+#   alone.
+test_expect_failure '4a-check: Change on A, change on B subset of A, dirty mods present' '
+	test_when_finished "git -C 4a reset --hard" &&
+	test_when_finished "git -C 4a clean -fd" &&
+	(
+		cd 4a &&
+
+		git checkout A^0 &&
+		echo "File rewritten" >b &&
+
+		test-tool chmtime =31337 b &&
+		test-tool chmtime -v +0 b >expected-mtime &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep "Skipped b" out &&
+		test_must_be_empty err &&
+
+		test-tool chmtime -v +0 b >actual-mtime &&
+		test_cmp expected-mtime actual-mtime &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 1 index_files &&
+
+		git rev-parse >actual :0:b &&
+		git rev-parse >expect A:b &&
+		test_cmp expect actual &&
+
+		git hash-object b >actual &&
+		echo "File rewritten" | git hash-object --stdin >expect &&
+		test_cmp expect actual
+	)
+'
+
+# Testcase 4b, Changed+renamed on A, subset of changes on B, locally modified
+#   Commit O: b_1
+#   Commit A: c_2
+#   Commit B: b_3
+#   Working copy: c_4
+#   Expected: c_2
+
+test_expect_success '4b-setup: Rename+Mod(A)/Mod(B), change on B subset of A, dirty mods present' '
+	test_create_repo 4b &&
+	(
+		cd 4b &&
+
+		test_write_lines 1 2 3 4 5 6 7 8 9 10 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_write_lines 1 2 3 4 5 5.5 6 7 8 9 10 10.5 >b &&
+		git add b &&
+		git mv b c &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		test_write_lines 1 2 3 4 5 5.5 6 7 8 9 10 >b &&
+		git add b &&
+		test_tick &&
+		git commit -m "B"
+	)
+'
+
+test_expect_success '4b-check: Rename+Mod(A)/Mod(B), change on B subset of A, dirty mods present' '
+	test_when_finished "git -C 4b reset --hard" &&
+	test_when_finished "git -C 4b clean -fd" &&
+	(
+		cd 4b &&
+
+		git checkout A^0 &&
+		echo "File rewritten" >c &&
+
+		test-tool chmtime =31337 c &&
+		test-tool chmtime -v +0 c >expected-mtime &&
+
+		GIT_MERGE_VERBOSITY=3 git merge -s recursive B^0 >out 2>err &&
+
+		test_i18ngrep "Skipped c" out &&
+		test_must_be_empty err &&
+
+		test-tool chmtime -v +0 c >actual-mtime &&
+		test_cmp expected-mtime actual-mtime &&
+
+		git ls-files -s >index_files &&
+		test_line_count = 1 index_files &&
+
+		git rev-parse >actual :0:c &&
+		git rev-parse >expect A:c &&
+		test_cmp expect actual &&
+
+		git hash-object c >actual &&
+		echo "File rewritten" | git hash-object --stdin >expect &&
+		test_cmp expect actual &&
+
+		test_must_fail git rev-parse HEAD:b &&
+		test_path_is_missing b
+	)
+'
+
+test_done
diff --git a/t/t6050-replace.sh b/t/t6050-replace.sh
index c630aba..aa3e249 100755
--- a/t/t6050-replace.sh
+++ b/t/t6050-replace.sh
@@ -4,8 +4,6 @@
 #
 test_description='Tests replace refs functionality'
 
-exec </dev/null
-
 . ./test-lib.sh
 . "$TEST_DIRECTORY/lib-gpg.sh"
 
@@ -444,4 +442,32 @@
 	git replace -d $HASH10
 '
 
+test_expect_success '--convert-graft-file' '
+	git checkout -b with-graft-file &&
+	test_commit root2 &&
+	git reset --hard root2^ &&
+	test_commit root1 &&
+	test_commit after-root1 &&
+	test_tick &&
+	git merge -m merge-root2 root2 &&
+
+	: add and convert graft file &&
+	printf "%s\n%s %s\n\n# comment\n%s\n" \
+		$(git rev-parse HEAD^^ HEAD^ HEAD^^ HEAD^2) \
+		>.git/info/grafts &&
+	git replace --convert-graft-file &&
+	test_path_is_missing .git/info/grafts &&
+
+	: verify that the history is now "grafted" &&
+	git rev-list HEAD >out &&
+	test_line_count = 4 out &&
+
+	: create invalid graft file and verify that it is not deleted &&
+	test_when_finished "rm -f .git/info/grafts" &&
+	echo $EMPTY_BLOB $EMPTY_TREE >.git/info/grafts &&
+	test_must_fail git replace --convert-graft-file 2>err &&
+	test_i18ngrep "$EMPTY_BLOB $EMPTY_TREE" err &&
+	test_i18ngrep "$EMPTY_BLOB $EMPTY_TREE" .git/info/grafts
+'
+
 test_done
diff --git a/t/t6101-rev-parse-parents.sh b/t/t6101-rev-parse-parents.sh
index 8c61798..7683e4a 100755
--- a/t/t6101-rev-parse-parents.sh
+++ b/t/t6101-rev-parse-parents.sh
@@ -214,4 +214,12 @@
 	test_must_fail git rev-list merge^-1x
 '
 
+test_expect_success 'rev-parse $garbage^@ does not segfault' '
+	test_must_fail git rev-parse $EMPTY_TREE^@
+'
+
+test_expect_success 'rev-parse $garbage...$garbage does not segfault' '
+	test_must_fail git rev-parse $EMPTY_TREE...$EMPTY_BLOB
+'
+
 test_done
diff --git a/t/t6111-rev-list-treesame.sh b/t/t6111-rev-list-treesame.sh
index 32474c2..4244638 100755
--- a/t/t6111-rev-list-treesame.sh
+++ b/t/t6111-rev-list-treesame.sh
@@ -20,7 +20,7 @@
 }
 
 unnote () {
-	git name-rev --tags --stdin | sed -e "s|$_x40 (tags/\([^)]*\))\([ 	]\)|\1\2|g"
+	git name-rev --tags --stdin | sed -e "s|$OID_REGEX (tags/\([^)]*\))\([ 	]\)|\1\2|g"
 }
 
 test_expect_success setup '
diff --git a/t/t6120-describe.sh b/t/t6120-describe.sh
index bae78c4..84dd1cb 100755
--- a/t/t6120-describe.sh
+++ b/t/t6120-describe.sh
@@ -383,7 +383,7 @@
 '
 
 test_expect_success 'describe complains about missing object' '
-	test_must_fail git describe $_z40
+	test_must_fail git describe $ZERO_OID
 '
 
 test_done
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index 295d147..48379aa 100755
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -310,7 +310,7 @@
 	echo >expected &&
 	git for-each-ref --format="%(authordate:format:)" refs/heads >actual &&
 	test_cmp expected actual &&
-	long="long format -- $_z40$_z40$_z40$_z40$_z40$_z40$_z40" &&
+	long="long format -- $ZERO_OID$ZERO_OID$ZERO_OID$ZERO_OID$ZERO_OID$ZERO_OID$ZERO_OID" &&
 	echo $long >expected &&
 	git for-each-ref --format="%(authordate:format:$long)" refs/heads >actual &&
 	test_cmp expected actual
diff --git a/t/t6301-for-each-ref-errors.sh b/t/t6301-for-each-ref-errors.sh
index c734ce2..49cc65b 100755
--- a/t/t6301-for-each-ref-errors.sh
+++ b/t/t6301-for-each-ref-errors.sh
@@ -4,7 +4,7 @@
 
 . ./test-lib.sh
 
-ZEROS=$_z40
+ZEROS=$ZERO_OID
 MISSING=abababababababababababababababababababab
 
 test_expect_success setup '
diff --git a/t/t6500-gc.sh b/t/t6500-gc.sh
index d5255dd..818435f 100755
--- a/t/t6500-gc.sh
+++ b/t/t6500-gc.sh
@@ -5,6 +5,13 @@
 
 . ./test-lib.sh
 
+test_expect_success 'setup' '
+	# do not let the amount of physical memory affects gc
+	# behavior, make sure we always pack everything to one pack by
+	# default
+	git config gc.bigPackThreshold 2g
+'
+
 test_expect_success 'gc empty repository' '
 	git gc
 '
@@ -43,6 +50,31 @@
 	)
 '
 
+test_expect_success 'gc --keep-largest-pack' '
+	test_create_repo keep-pack &&
+	(
+		cd keep-pack &&
+		test_commit one &&
+		test_commit two &&
+		test_commit three &&
+		git gc &&
+		( cd .git/objects/pack && ls *.pack ) >pack-list &&
+		test_line_count = 1 pack-list &&
+		BASE_PACK=.git/objects/pack/pack-*.pack &&
+		test_commit four &&
+		git repack -d &&
+		test_commit five &&
+		git repack -d &&
+		( cd .git/objects/pack && ls *.pack ) >pack-list &&
+		test_line_count = 3 pack-list &&
+		git gc --keep-largest-pack &&
+		( cd .git/objects/pack && ls *.pack ) >pack-list &&
+		test_line_count = 2 pack-list &&
+		test_path_is_file $BASE_PACK &&
+		git fsck
+	)
+'
+
 test_expect_success 'auto gc with too many loose objects does not attempt to create bitmaps' '
 	test_config gc.auto 3 &&
 	test_config gc.autodetach false &&
diff --git a/t/t7001-mv.sh b/t/t7001-mv.sh
index e96cbdb..cc3fd2b 100755
--- a/t/t7001-mv.sh
+++ b/t/t7001-mv.sh
@@ -495,7 +495,7 @@
 	test_cmp expect actual
 '
 
-test_expect_failure 'moving nested submodules' '
+test_expect_success 'moving nested submodules' '
 	git commit -am "cleanup commit" &&
 	mkdir sub_nested_nested &&
 	(cd sub_nested_nested &&
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index 2aac77a..d7b319e 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -363,7 +363,7 @@
 '
 
 test_expect_success 'listing tags in column' '
-	COLUMNS=40 git tag -l --column=row >actual &&
+	COLUMNS=41 git tag -l --column=row >actual &&
 	cat >expected <<\EOF &&
 a1      aa1     cba     t210    t211
 v0.2.1  v1.0    v1.0.1  v1.1.3
@@ -1056,7 +1056,18 @@
 	git tag -s -F sigblanknonlfile blanknonlfile-signed-tag &&
 	get_tag_msg blanknonlfile-signed-tag >actual &&
 	test_cmp expect actual &&
-	git tag -v signed-tag
+	git tag -v blanknonlfile-signed-tag
+'
+
+test_expect_success GPG 'signed tag with embedded PGP message' '
+	cat >msg <<-\EOF &&
+	-----BEGIN PGP MESSAGE-----
+
+	this is not a real PGP message
+	-----END PGP MESSAGE-----
+	EOF
+	git tag -s -F msg confusing-pgp-message &&
+	git tag -v confusing-pgp-message
 '
 
 # messages with commented lines for signed tags:
diff --git a/t/t7005-editor.sh b/t/t7005-editor.sh
index 29e5043..b2ca77b 100755
--- a/t/t7005-editor.sh
+++ b/t/t7005-editor.sh
@@ -111,14 +111,8 @@
 	'
 done
 
-if echo 'echo space > "$1"' > "e space.sh"
-then
-	# FS supports spaces in filenames
-	test_set_prereq SPACES_IN_FILENAMES
-fi
-
-test_expect_success SPACES_IN_FILENAMES 'editor with a space' '
-
+test_expect_success 'editor with a space' '
+	echo "echo space >\$1" >"e space.sh" &&
 	chmod a+x "e space.sh" &&
 	GIT_EDITOR="./e\ space.sh" git commit --amend &&
 	test space = "$(git show -s --pretty=format:%s)"
@@ -126,7 +120,7 @@
 '
 
 unset GIT_EDITOR
-test_expect_success SPACES_IN_FILENAMES 'core.editor with a space' '
+test_expect_success 'core.editor with a space' '
 
 	git config core.editor \"./e\ space.sh\" &&
 	git commit --amend &&
diff --git a/t/t7009-filter-branch-null-sha1.sh b/t/t7009-filter-branch-null-sha1.sh
index a8d9ec4..9ba9f24 100755
--- a/t/t7009-filter-branch-null-sha1.sh
+++ b/t/t7009-filter-branch-null-sha1.sh
@@ -12,7 +12,7 @@
 test_expect_success 'setup: a commit with a bogus null sha1 in the tree' '
 	{
 		git ls-tree HEAD &&
-		printf "160000 commit $_z40\\tbroken\\n"
+		printf "160000 commit $ZERO_OID\\tbroken\\n"
 	} >broken-tree &&
 	echo "add broken entry" >msg &&
 
diff --git a/t/t7011-skip-worktree-reading.sh b/t/t7011-skip-worktree-reading.sh
index 84f4145..37525ca 100755
--- a/t/t7011-skip-worktree-reading.sh
+++ b/t/t7011-skip-worktree-reading.sh
@@ -118,7 +118,7 @@
 	test "$(git grep --no-ext-grep test)" = "1:test"
 '
 
-echo ":000000 100644 $_z40 $EMPTY_BLOB A	1" > expected
+echo ":000000 100644 $ZERO_OID $EMPTY_BLOB A	1" > expected
 test_expect_success 'diff-index does not examine skip-worktree absent entries' '
 	setup_absent &&
 	git diff-index HEAD -- 1 > result &&
diff --git a/t/t7064-wtstatus-pv2.sh b/t/t7064-wtstatus-pv2.sh
index 8f79532..b9a86d3 100755
--- a/t/t7064-wtstatus-pv2.sh
+++ b/t/t7064-wtstatus-pv2.sh
@@ -46,11 +46,11 @@
 	cat >expect <<-EOF &&
 	# branch.oid (initial)
 	# branch.head master
-	1 A. N... 000000 100644 100644 $_z40 $OID_A dir1/file_a
-	1 A. N... 000000 100644 100644 $_z40 $OID_B dir1/file_b
-	1 A. N... 000000 100644 100644 $_z40 $OID_X file_x
-	1 A. N... 000000 100644 100644 $_z40 $OID_Y file_y
-	1 A. N... 000000 100644 100644 $_z40 $OID_Z file_z
+	1 A. N... 000000 100644 100644 $ZERO_OID $OID_A dir1/file_a
+	1 A. N... 000000 100644 100644 $ZERO_OID $OID_B dir1/file_b
+	1 A. N... 000000 100644 100644 $ZERO_OID $OID_X file_x
+	1 A. N... 000000 100644 100644 $ZERO_OID $OID_Y file_y
+	1 A. N... 000000 100644 100644 $ZERO_OID $OID_Z file_z
 	? actual
 	? expect
 	EOF
@@ -63,11 +63,11 @@
 	lf_to_nul >expect <<-EOF &&
 	# branch.oid (initial)
 	# branch.head master
-	1 A. N... 000000 100644 100644 $_z40 $OID_A dir1/file_a
-	1 A. N... 000000 100644 100644 $_z40 $OID_B dir1/file_b
-	1 A. N... 000000 100644 100644 $_z40 $OID_X file_x
-	1 A. N... 000000 100644 100644 $_z40 $OID_Y file_y
-	1 A. N... 000000 100644 100644 $_z40 $OID_Z file_z
+	1 A. N... 000000 100644 100644 $ZERO_OID $OID_A dir1/file_a
+	1 A. N... 000000 100644 100644 $ZERO_OID $OID_B dir1/file_b
+	1 A. N... 000000 100644 100644 $ZERO_OID $OID_X file_x
+	1 A. N... 000000 100644 100644 $ZERO_OID $OID_Y file_y
+	1 A. N... 000000 100644 100644 $ZERO_OID $OID_Z file_z
 	? actual
 	? expect
 	EOF
@@ -128,7 +128,7 @@
 	# branch.oid $H0
 	# branch.head master
 	1 M. N... 100644 100644 100644 $OID_X $OID_X1 file_x
-	1 D. N... 100644 000000 000000 $OID_Z $_z40 file_z
+	1 D. N... 100644 000000 000000 $OID_Z $ZERO_OID file_z
 	? actual
 	? expect
 	EOF
@@ -145,7 +145,7 @@
 	# branch.oid $H0
 	# branch.head master
 	1 M. N... 100644 100644 100644 $OID_X $OID_X1 file_x
-	1 D. N... 100644 000000 000000 $OID_Z $_z40 file_z
+	1 D. N... 100644 000000 000000 $OID_Z $ZERO_OID file_z
 	2 R. N... 100644 100644 100644 $OID_Y $OID_Y R100 renamed_yQfile_y
 	? actual
 	? expect
@@ -163,7 +163,7 @@
 	# branch.oid $H0
 	# branch.head master
 	1 M. N... 100644 100644 100644 $OID_X $OID_X1 file_x
-	1 D. N... 100644 000000 000000 $OID_Z $_z40 file_z
+	1 D. N... 100644 000000 000000 $OID_Z $ZERO_OID file_z
 	2 R. N... 100644 100644 100644 $OID_Y $OID_Y R100 renamed_yQfile_y
 	? actual
 	? expect
@@ -246,8 +246,8 @@
 	git add --intent-to-add intent1.add intent2.add &&
 
 	cat >expect <<-EOF &&
-	1 .A N... 000000 000000 100644 $_z40 $_z40 intent1.add
-	1 .A N... 000000 000000 100644 $_z40 $_z40 intent2.add
+	1 .A N... 000000 000000 100644 $ZERO_OID $ZERO_OID intent1.add
+	1 .A N... 000000 000000 100644 $ZERO_OID $ZERO_OID intent2.add
 	EOF
 
 	git status --porcelain=v2 >actual &&
@@ -280,7 +280,7 @@
 	cat >expect <<-EOF &&
 	# branch.oid $HM
 	# branch.head AA_M
-	u AA N... 000000 100644 100644 100644 $_z40 $OID_AA_B $OID_AA_A conflict.txt
+	u AA N... 000000 100644 100644 100644 $ZERO_OID $OID_AA_B $OID_AA_A conflict.txt
 	EOF
 
 	git status --porcelain=v2 --branch --untracked-files=all >actual &&
@@ -373,7 +373,7 @@
 		## Test upstream-gone case. Fake this by pointing origin/master at
 		## a non-existing commit.
 		OLD=$(git rev-parse origin/master) &&
-		NEW=$_z40 &&
+		NEW=$ZERO_OID &&
 		mv .git/packed-refs .git/old-packed-refs &&
 		sed "s/$OLD/$NEW/g" <.git/old-packed-refs >.git/packed-refs &&
 
@@ -469,8 +469,8 @@
 		# branch.head master
 		# branch.upstream origin/master
 		# branch.ab +0 -0
-		1 A. N... 000000 100644 100644 $_z40 $HMOD .gitmodules
-		1 A. S... 000000 160000 160000 $_z40 $HSUB sub1
+		1 A. N... 000000 100644 100644 $ZERO_OID $HMOD .gitmodules
+		1 A. S... 000000 160000 160000 $ZERO_OID $HSUB sub1
 		EOF
 
 		git status --porcelain=v2 --branch --untracked-files=all >actual &&
@@ -494,8 +494,8 @@
 		# branch.head master
 		# branch.upstream origin/master
 		# branch.ab +0 -0
-		1 A. N... 000000 100644 100644 $_z40 $HMOD .gitmodules
-		1 AM S..U 000000 160000 160000 $_z40 $HSUB sub1
+		1 A. N... 000000 100644 100644 $ZERO_OID $HMOD .gitmodules
+		1 AM S..U 000000 160000 160000 $ZERO_OID $HSUB sub1
 		EOF
 
 		git status --porcelain=v2 --branch --untracked-files=all >actual &&
@@ -519,8 +519,8 @@
 		# branch.head master
 		# branch.upstream origin/master
 		# branch.ab +0 -0
-		1 A. N... 000000 100644 100644 $_z40 $HMOD .gitmodules
-		1 AM S.M. 000000 160000 160000 $_z40 $HSUB sub1
+		1 A. N... 000000 100644 100644 $ZERO_OID $HMOD .gitmodules
+		1 AM S.M. 000000 160000 160000 $ZERO_OID $HSUB sub1
 		EOF
 
 		git status --porcelain=v2 --branch --untracked-files=all >actual &&
@@ -546,8 +546,8 @@
 		# branch.head master
 		# branch.upstream origin/master
 		# branch.ab +0 -0
-		1 A. N... 000000 100644 100644 $_z40 $HMOD .gitmodules
-		1 AM S.M. 000000 160000 160000 $_z40 $HSUB sub1
+		1 A. N... 000000 100644 100644 $ZERO_OID $HMOD .gitmodules
+		1 AM S.M. 000000 160000 160000 $ZERO_OID $HSUB sub1
 		EOF
 
 		git status --porcelain=v2 --branch --untracked-files=all >actual &&
@@ -573,8 +573,8 @@
 		# branch.head master
 		# branch.upstream origin/master
 		# branch.ab +0 -0
-		1 A. N... 000000 100644 100644 $_z40 $HMOD .gitmodules
-		1 AM S.MU 000000 160000 160000 $_z40 $HSUB sub1
+		1 A. N... 000000 100644 100644 $ZERO_OID $HMOD .gitmodules
+		1 AM S.MU 000000 160000 160000 $ZERO_OID $HSUB sub1
 		EOF
 
 		git status --porcelain=v2 --branch --untracked-files=all >actual &&
@@ -600,8 +600,8 @@
 		# branch.head master
 		# branch.upstream origin/master
 		# branch.ab +0 -0
-		1 A. N... 000000 100644 100644 $_z40 $HMOD .gitmodules
-		1 AM SC.. 000000 160000 160000 $_z40 $HSUB sub1
+		1 A. N... 000000 100644 100644 $ZERO_OID $HMOD .gitmodules
+		1 AM SC.. 000000 160000 160000 $ZERO_OID $HSUB sub1
 		EOF
 
 		git status --porcelain=v2 --branch --untracked-files=all >actual &&
diff --git a/t/t7201-co.sh b/t/t7201-co.sh
index 76c223c..ab9da61 100755
--- a/t/t7201-co.sh
+++ b/t/t7201-co.sh
@@ -65,7 +65,7 @@
 test_expect_success "checkout from non-existing branch" '
 
 	git checkout -b delete-me master &&
-	rm .git/refs/heads/delete-me &&
+	git update-ref -d --no-deref refs/heads/delete-me &&
 	test refs/heads/delete-me = "$(git symbolic-ref HEAD)" &&
 	git checkout master &&
 	test refs/heads/master = "$(git symbolic-ref HEAD)"
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index 1521044..2f53252 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -126,6 +126,22 @@
 	test_cmp empty untracked
 '
 
+test_create_repo parent &&
+test_commit -C parent one
+
+test_expect_success 'redirected submodule add does not show progress' '
+	git -C addtest submodule add "file://$submodurl/parent" submod-redirected \
+		2>err &&
+	! grep % err &&
+	test_i18ngrep ! "Checking connectivity" err
+'
+
+test_expect_success 'redirected submodule add --progress does show progress' '
+	git -C addtest submodule add --progress "file://$submodurl/parent" \
+		submod-redirected-progress 2>err && \
+	grep % err
+'
+
 test_expect_success 'submodule add to .gitignored path fails' '
 	(
 		cd addtest-ignore &&
diff --git a/t/t7408-submodule-reference.sh b/t/t7408-submodule-reference.sh
index e159fc5..08d9add 100755
--- a/t/t7408-submodule-reference.sh
+++ b/t/t7408-submodule-reference.sh
@@ -59,6 +59,16 @@
 	test_alternate_is_used super/.git/modules/sub/objects/info/alternates super/sub
 '
 
+test_expect_success 'submodule add --reference with --dissociate does not use alternates' '
+	(
+		cd super &&
+		git submodule add --reference ../B --dissociate "file://$base_dir/A" sub-dissociate &&
+		git commit -m B-super-added &&
+		git repack -ad
+	) &&
+	test_path_is_missing super/.git/modules/sub-dissociate/objects/info/alternates
+'
+
 test_expect_success 'that reference gets used with add' '
 	(
 		cd super/sub &&
@@ -82,6 +92,13 @@
 	test_alternate_is_used super-clone/.git/modules/sub/objects/info/alternates super-clone/sub
 '
 
+test_expect_success 'updating superproject with --dissociate does not keep alternates' '
+	test_when_finished "rm -rf super-clone" &&
+	git clone super super-clone &&
+	git -C super-clone submodule update --init --reference ../B --dissociate &&
+	test_path_is_missing super-clone/.git/modules/sub/objects/info/alternates
+'
+
 test_expect_success 'submodules use alternates when cloning a superproject' '
 	test_when_finished "rm -rf super-clone" &&
 	git clone --reference super --recursive super super-clone &&
diff --git a/t/t7415-submodule-names.sh b/t/t7415-submodule-names.sh
new file mode 100755
index 0000000..a770d92
--- /dev/null
+++ b/t/t7415-submodule-names.sh
@@ -0,0 +1,154 @@
+#!/bin/sh
+
+test_description='check handling of .. in submodule names
+
+Exercise the name-checking function on a variety of names, and then give a
+real-world setup that confirms we catch this in practice.
+'
+. ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-pack.sh
+
+test_expect_success 'check names' '
+	cat >expect <<-\EOF &&
+	valid
+	valid/with/paths
+	EOF
+
+	git submodule--helper check-name >actual <<-\EOF &&
+	valid
+	valid/with/paths
+
+	../foo
+	/../foo
+	..\foo
+	\..\foo
+	foo/..
+	foo/../
+	foo\..
+	foo\..\
+	foo/../bar
+	EOF
+
+	test_cmp expect actual
+'
+
+test_expect_success 'create innocent subrepo' '
+	git init innocent &&
+	git -C innocent commit --allow-empty -m foo
+'
+
+test_expect_success 'submodule add refuses invalid names' '
+	test_must_fail \
+		git submodule add --name ../../modules/evil "$PWD/innocent" evil
+'
+
+test_expect_success 'add evil submodule' '
+	git submodule add "$PWD/innocent" evil &&
+
+	mkdir modules &&
+	cp -r .git/modules/evil modules &&
+	write_script modules/evil/hooks/post-checkout <<-\EOF &&
+	echo >&2 "RUNNING POST CHECKOUT"
+	EOF
+
+	git config -f .gitmodules submodule.evil.update checkout &&
+	git config -f .gitmodules --rename-section \
+		submodule.evil submodule.../../modules/evil &&
+	git add modules &&
+	git commit -am evil
+'
+
+# This step seems like it shouldn't be necessary, since the payload is
+# contained entirely in the evil submodule. But due to the vagaries of the
+# submodule code, checking out the evil module will fail unless ".git/modules"
+# exists. Adding another submodule (with a name that sorts before "evil") is an
+# easy way to make sure this is the case in the victim clone.
+test_expect_success 'add other submodule' '
+	git submodule add "$PWD/innocent" another-module &&
+	git add another-module &&
+	git commit -am another
+'
+
+test_expect_success 'clone evil superproject' '
+	git clone --recurse-submodules . victim >output 2>&1 &&
+	! grep "RUNNING POST CHECKOUT" output
+'
+
+test_expect_success 'fsck detects evil superproject' '
+	test_must_fail git fsck
+'
+
+test_expect_success 'transfer.fsckObjects detects evil superproject (unpack)' '
+	rm -rf dst.git &&
+	git init --bare dst.git &&
+	git -C dst.git config transfer.fsckObjects true &&
+	test_must_fail git push dst.git HEAD
+'
+
+test_expect_success 'transfer.fsckObjects detects evil superproject (index)' '
+	rm -rf dst.git &&
+	git init --bare dst.git &&
+	git -C dst.git config transfer.fsckObjects true &&
+	git -C dst.git config transfer.unpackLimit 1 &&
+	test_must_fail git push dst.git HEAD
+'
+
+# Normally our packs contain commits followed by trees followed by blobs. This
+# reverses the order, which requires backtracking to find the context of a
+# blob. We'll start with a fresh gitmodules-only tree to make it simpler.
+test_expect_success 'create oddly ordered pack' '
+	git checkout --orphan odd &&
+	git rm -rf --cached . &&
+	git add .gitmodules &&
+	git commit -m odd &&
+	{
+		pack_header 3 &&
+		pack_obj $(git rev-parse HEAD:.gitmodules) &&
+		pack_obj $(git rev-parse HEAD^{tree}) &&
+		pack_obj $(git rev-parse HEAD)
+	} >odd.pack &&
+	pack_trailer odd.pack
+'
+
+test_expect_success 'transfer.fsckObjects handles odd pack (unpack)' '
+	rm -rf dst.git &&
+	git init --bare dst.git &&
+	test_must_fail git -C dst.git unpack-objects --strict <odd.pack
+'
+
+test_expect_success 'transfer.fsckObjects handles odd pack (index)' '
+	rm -rf dst.git &&
+	git init --bare dst.git &&
+	test_must_fail git -C dst.git index-pack --strict --stdin <odd.pack
+'
+
+test_expect_success 'fsck detects symlinked .gitmodules file' '
+	git init symlink &&
+	(
+		cd symlink &&
+
+		# Make the tree directly to avoid index restrictions.
+		#
+		# Because symlinks store the target as a blob, choose
+		# a pathname that could be parsed as a .gitmodules file
+		# to trick naive non-symlink-aware checking.
+		tricky="[foo]bar=true" &&
+		content=$(git hash-object -w ../.gitmodules) &&
+		target=$(printf "$tricky" | git hash-object -w --stdin) &&
+		tree=$(
+			{
+				printf "100644 blob $content\t$tricky\n" &&
+				printf "120000 blob $target\t.gitmodules\n"
+			} | git mktree
+		) &&
+		commit=$(git commit-tree $tree) &&
+
+		# Check not only that we fail, but that it is due to the
+		# symlink detector; this grep string comes from the config
+		# variable name and will not be translated.
+		test_must_fail git fsck 2>output &&
+		grep gitmodulesSymlink output
+	)
+'
+
+test_done
diff --git a/t/t7506-status-submodule.sh b/t/t7506-status-submodule.sh
index 9edf657..b4b74db 100755
--- a/t/t7506-status-submodule.sh
+++ b/t/t7506-status-submodule.sh
@@ -18,7 +18,7 @@
 }
 
 sanitize_output () {
-	sed -e "s/$_x40/HASH/" -e "s/$_x40/HASH/" output >output2 &&
+	sed -e "s/$OID_REGEX/HASH/" -e "s/$OID_REGEX/HASH/" output >output2 &&
 	mv output2 output
 }
 
diff --git a/t/t7525-status-rename.sh b/t/t7525-status-rename.sh
new file mode 100755
index 0000000..ef8b1b3
--- /dev/null
+++ b/t/t7525-status-rename.sh
@@ -0,0 +1,113 @@
+#!/bin/sh
+
+test_description='git status rename detection options'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	echo 1 >original &&
+	git add . &&
+	git commit -m"Adding original file." &&
+	mv original renamed &&
+	echo 2 >> renamed &&
+	git add . &&
+	cat >.gitignore <<-\EOF
+	.gitignore
+	expect*
+	actual*
+	EOF
+'
+
+test_expect_success 'status no-options' '
+	git status >actual &&
+	test_i18ngrep "renamed:" actual
+'
+
+test_expect_success 'status --no-renames' '
+	git status --no-renames >actual &&
+	test_i18ngrep "deleted:" actual &&
+	test_i18ngrep "new file:" actual
+'
+
+test_expect_success 'status.renames inherits from diff.renames false' '
+	git -c diff.renames=false status >actual &&
+	test_i18ngrep "deleted:" actual &&
+	test_i18ngrep "new file:" actual
+'
+
+test_expect_success 'status.renames inherits from diff.renames true' '
+	git -c diff.renames=true status >actual &&
+	test_i18ngrep "renamed:" actual
+'
+
+test_expect_success 'status.renames overrides diff.renames false' '
+	git -c diff.renames=true -c status.renames=false status >actual &&
+	test_i18ngrep "deleted:" actual &&
+	test_i18ngrep "new file:" actual
+'
+
+test_expect_success 'status.renames overrides from diff.renames true' '
+	git -c diff.renames=false -c status.renames=true status >actual &&
+	test_i18ngrep "renamed:" actual
+'
+
+test_expect_success 'status status.renames=false' '
+	git -c status.renames=false status >actual &&
+	test_i18ngrep "deleted:" actual &&
+	test_i18ngrep "new file:" actual
+'
+
+test_expect_success 'status status.renames=true' '
+	git -c status.renames=true status >actual &&
+	test_i18ngrep "renamed:" actual
+'
+
+test_expect_success 'commit honors status.renames=false' '
+	git -c status.renames=false commit --dry-run >actual &&
+	test_i18ngrep "deleted:" actual &&
+	test_i18ngrep "new file:" actual
+'
+
+test_expect_success 'commit honors status.renames=true' '
+	git -c status.renames=true commit --dry-run >actual &&
+	test_i18ngrep "renamed:" actual
+'
+
+test_expect_success 'status config overridden' '
+	git -c status.renames=true status --no-renames >actual &&
+	test_i18ngrep "deleted:" actual &&
+	test_i18ngrep "new file:" actual
+'
+
+test_expect_success 'status score=100%' '
+	git status -M=100% >actual &&
+	test_i18ngrep "deleted:" actual &&
+	test_i18ngrep "new file:" actual &&
+
+	git status --find-rename=100% >actual &&
+	test_i18ngrep "deleted:" actual &&
+	test_i18ngrep "new file:" actual
+'
+
+test_expect_success 'status score=01%' '
+	git status -M=01% >actual &&
+	test_i18ngrep "renamed:" actual &&
+
+	git status --find-rename=01% >actual &&
+	test_i18ngrep "renamed:" actual
+'
+
+test_expect_success 'copies not overridden by find-rename' '
+	cp renamed copy &&
+	git add copy &&
+
+	git -c status.renames=copies status -M=01% >actual &&
+	test_i18ngrep "copied:" actual &&
+	test_i18ngrep "renamed:" actual &&
+
+	git -c status.renames=copies status --find-rename=01% >actual &&
+	test_i18ngrep "copied:" actual &&
+	test_i18ngrep "renamed:" actual
+'
+
+test_done
diff --git a/t/t7607-merge-overwrite.sh b/t/t7607-merge-overwrite.sh
index 9c422bc..dd8ab7e 100755
--- a/t/t7607-merge-overwrite.sh
+++ b/t/t7607-merge-overwrite.sh
@@ -92,7 +92,7 @@
 	test_cmp important c1.c
 '
 
-test_expect_failure 'will not overwrite unstaged changes in renamed file' '
+test_expect_success 'will not overwrite unstaged changes in renamed file' '
 	git reset --hard c1 &&
 	git mv c1.c other.c &&
 	git commit -m rename &&
diff --git a/t/t7700-repack.sh b/t/t7700-repack.sh
index 6061a04..6162e2a 100755
--- a/t/t7700-repack.sh
+++ b/t/t7700-repack.sh
@@ -4,6 +4,12 @@
 
 . ./test-lib.sh
 
+commit_and_pack() {
+	test_commit "$@" >/dev/null &&
+	SHA1=$(git pack-objects --all --unpacked --incremental .git/objects/pack/pack </dev/null) &&
+	echo pack-${SHA1}.pack
+}
+
 test_expect_success 'objects in packs marked .keep are not repacked' '
 	echo content1 > file1 &&
 	echo content2 > file2 &&
@@ -194,7 +200,26 @@
 	git reflog expire --expire=$test_tick --expire-unreachable=$test_tick --all &&
 	git repack -a -d &&
 	git cat-file -t $H1
-	'
+'
+
+test_expect_success 'repack --keep-pack' '
+	test_create_repo keep-pack &&
+	(
+		cd keep-pack &&
+		P1=$(commit_and_pack 1) &&
+		P2=$(commit_and_pack 2) &&
+		P3=$(commit_and_pack 3) &&
+		P4=$(commit_and_pack 4) &&
+		ls .git/objects/pack/*.pack >old-counts &&
+		test_line_count = 4 old-counts &&
+		git repack -a -d --keep-pack $P1 --keep-pack $P4 &&
+		ls .git/objects/pack/*.pack >new-counts &&
+		grep -q $P1 new-counts &&
+		grep -q $P4 new-counts &&
+		test_line_count = 3 new-counts &&
+		git fsck
+	)
+'
 
 test_done
 
diff --git a/t/t8012-blame-colors.sh b/t/t8012-blame-colors.sh
new file mode 100755
index 0000000..ed38f74
--- /dev/null
+++ b/t/t8012-blame-colors.sh
@@ -0,0 +1,48 @@
+#!/bin/sh
+
+test_description='colored git blame'
+. ./test-lib.sh
+
+PROG='git blame -c'
+. "$TEST_DIRECTORY"/annotate-tests.sh
+
+test_expect_success 'colored blame colors contiguous lines' '
+	git -c color.blame.repeatedLines=yellow blame --color-lines --abbrev=12 hello.c >actual.raw &&
+	git -c color.blame.repeatedLines=yellow -c blame.coloring=repeatedLines blame --abbrev=12 hello.c >actual.raw.2 &&
+	test_cmp actual.raw actual.raw.2 &&
+	test_decode_color <actual.raw >actual &&
+	grep "<YELLOW>" <actual >darkened &&
+	grep "(F" darkened > F.expect &&
+	grep "(H" darkened > H.expect &&
+	test_line_count = 2 F.expect &&
+	test_line_count = 3 H.expect
+'
+
+test_expect_success 'color by age consistently colors old code' '
+	git blame --color-by-age hello.c >actual.raw &&
+	git -c blame.coloring=highlightRecent blame hello.c >actual.raw.2 &&
+	test_cmp actual.raw actual.raw.2 &&
+	test_decode_color <actual.raw >actual &&
+	grep "<BLUE>" <actual >colored &&
+	test_line_count = 10 colored
+'
+
+test_expect_success 'blame color by age: new code is different' '
+	cat >>hello.c <<-EOF &&
+		void qfunc();
+	EOF
+	git add hello.c &&
+	GIT_AUTHOR_DATE="" git commit -m "new commit" &&
+
+	git -c color.blame.highlightRecent="yellow,1 month ago, cyan" blame --color-by-age hello.c >actual.raw &&
+	test_decode_color <actual.raw >actual &&
+
+	grep "<YELLOW>" <actual >colored &&
+	test_line_count = 10 colored &&
+
+	grep "<CYAN>" <actual >colored &&
+	test_line_count = 1 colored &&
+	grep qfunc colored
+'
+
+test_done
diff --git a/t/t9010-svn-fe.sh b/t/t9010-svn-fe.sh
index 8eaaca6..0b20b07 100755
--- a/t/t9010-svn-fe.sh
+++ b/t/t9010-svn-fe.sh
@@ -473,7 +473,7 @@
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
-		sed "s/$_x40/OBJID/g"
+		sed "s/$OID_REGEX/OBJID/g"
 	} >actual &&
 	git show HEAD:greeting >actual.blob &&
 	git show HEAD^:greeting >actual.target &&
@@ -573,7 +573,7 @@
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
-		sed "s/$_x40/OBJID/g"
+		sed "s/$OID_REGEX/OBJID/g"
 	} >actual &&
 	{
 		git cat-file commit HEAD | nul_to_q &&
@@ -659,7 +659,7 @@
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
-		sed "s/$_x40/OBJID/g"
+		sed "s/$OID_REGEX/OBJID/g"
 	} >actual &&
 	git show HEAD:greeting >actual.blob &&
 	git show HEAD^:greeting >actual.target &&
@@ -792,7 +792,7 @@
 	{
 		git rev-list HEAD |
 		git diff-tree --stdin |
-		sed "s/$_x40/OBJID/g"
+		sed "s/$OID_REGEX/OBJID/g"
 	} >actual &&
 	test_cmp expect actual
 '
@@ -846,7 +846,7 @@
 	{
 		git rev-list HEAD |
 		git diff-tree --root --always --stdin |
-		sed "s/$_x40/OBJID/g"
+		sed "s/$OID_REGEX/OBJID/g"
 	} >actual &&
 	test_cmp expect actual
 '
@@ -931,7 +931,7 @@
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
-		sed "s/$_x40/OBJID/g"
+		sed "s/$OID_REGEX/OBJID/g"
 	} >actual &&
 	test_cmp expect actual
 '
@@ -1030,7 +1030,7 @@
 	{
 		git rev-list HEAD |
 		git diff-tree --root --stdin |
-		sed "s/$_x40/OBJID/g"
+		sed "s/$OID_REGEX/OBJID/g"
 	} >actual &&
 	test_cmp expect actual &&
 	git show HEAD:postimage >actual.3 &&
diff --git a/t/t9104-git-svn-follow-parent.sh b/t/t9104-git-svn-follow-parent.sh
index a735fa3..9c49b6c 100755
--- a/t/t9104-git-svn-follow-parent.sh
+++ b/t/t9104-git-svn-follow-parent.sh
@@ -215,7 +215,8 @@
 	"
 
 test_expect_success "multi-fetch works off a 'clean' repository" '
-	rm -r "$GIT_DIR/svn" "$GIT_DIR/refs/remotes" "$GIT_DIR/logs" &&
+	rm -rf "$GIT_DIR/svn" "$GIT_DIR/refs/remotes" &&
+	git reflog expire --all --expire=all &&
 	mkdir "$GIT_DIR/svn" &&
 	git svn multi-fetch
 	'
diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index dc79df7..9e7f962 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -1185,7 +1185,7 @@
 	test_cmp expect.response response &&
 	git rev-list read-empty |
 	git diff-tree -r --root --stdin |
-	sed "s/$_x40/OBJNAME/g" >actual &&
+	sed "s/$OID_REGEX/OBJNAME/g" >actual &&
 	test_cmp expect actual
 '
 
@@ -1271,7 +1271,7 @@
 	git fast-import <input &&
 	git rev-list N-delete |
 		git diff-tree -r --stdin --root --always |
-		sed -e "s/$_x40/OBJID/g" >actual &&
+		sed -e "s/$OID_REGEX/OBJID/g" >actual &&
 	test_cmp expect actual
 '
 
@@ -2602,7 +2602,7 @@
 	EOF
 	git rev-list done-ends |
 	git diff-tree -r --stdin --root --always |
-	sed -e "s/$_x40/OBJID/g" >actual &&
+	sed -e "s/$OID_REGEX/OBJID/g" >actual &&
 	test_cmp expect actual
 '
 
diff --git a/t/t9350-fast-export.sh b/t/t9350-fast-export.sh
index d5679ff..6a392e8 100755
--- a/t/t9350-fast-export.sh
+++ b/t/t9350-fast-export.sh
@@ -538,4 +538,22 @@
 	test_cmp expected actual
 '
 
+test_expect_success 'merge commit gets exported with --import-marks' '
+	test_create_repo merging &&
+	(
+		cd merging &&
+		test_commit initial &&
+		git checkout -b topic &&
+		test_commit on-topic &&
+		git checkout master &&
+		test_commit on-master &&
+		test_tick &&
+		git merge --no-ff -m Yeah topic &&
+
+		echo ":1 $(git rev-parse HEAD^^)" >marks &&
+		git fast-export --import-marks=marks master >out &&
+		grep Yeah out
+	)
+'
+
 test_done
diff --git a/t/t9832-unshelve.sh b/t/t9832-unshelve.sh
new file mode 100755
index 0000000..48ec767
--- /dev/null
+++ b/t/t9832-unshelve.sh
@@ -0,0 +1,138 @@
+#!/bin/sh
+
+last_shelved_change () {
+	p4 changes -s shelved -m1 | cut -d " " -f 2
+}
+
+test_description='git p4 unshelve'
+
+. ./lib-git-p4.sh
+
+test_expect_success 'start p4d' '
+	start_p4d
+'
+
+test_expect_success 'init depot' '
+	(
+		cd "$cli" &&
+		echo file1 >file1 &&
+		p4 add file1 &&
+		p4 submit -d "change 1" &&
+		: >file_to_delete &&
+		p4 add file_to_delete &&
+		p4 submit -d "file to delete"
+	)
+'
+
+test_expect_success 'initial clone' '
+	git p4 clone --dest="$git" //depot/@all
+'
+
+test_expect_success 'create shelved changelist' '
+	(
+		cd "$cli" &&
+		p4 edit file1 &&
+		echo "a change" >>file1 &&
+		echo "new file" >file2 &&
+		p4 add file2 &&
+		p4 delete file_to_delete &&
+		p4 opened &&
+		p4 shelve -i <<EOF
+Change: new
+Description:
+	Test commit
+
+	Further description
+Files:
+	//depot/file1
+	//depot/file2
+	//depot/file_to_delete
+EOF
+
+	) &&
+	(
+		cd "$git" &&
+		change=$(last_shelved_change) &&
+		git p4 unshelve $change &&
+		git show refs/remotes/p4/unshelved/$change | grep -q "Further description" &&
+		git cherry-pick refs/remotes/p4/unshelved/$change &&
+		test_path_is_file file2 &&
+		test_cmp file1 "$cli"/file1 &&
+		test_cmp file2 "$cli"/file2 &&
+		test_path_is_missing file_to_delete
+	)
+'
+
+test_expect_success 'update shelved changelist and re-unshelve' '
+	test_when_finished cleanup_git &&
+	(
+		cd "$cli" &&
+		change=$(last_shelved_change) &&
+		echo "file3" >file3 &&
+		p4 add -c $change file3 &&
+		p4 shelve -i -r <<EOF &&
+Change: $change
+Description:
+	Test commit
+
+	Further description
+Files:
+	//depot/file1
+	//depot/file2
+	//depot/file3
+	//depot/file_to_delete
+EOF
+		p4 describe $change
+	) &&
+	(
+		cd "$git" &&
+		change=$(last_shelved_change) &&
+		git p4 unshelve $change &&
+		git diff refs/remotes/p4/unshelved/$change.0 refs/remotes/p4/unshelved/$change | grep -q file3
+	)
+'
+
+# This is the tricky case where the shelved changelist base revision doesn't
+# match git-p4's idea of the base revision
+#
+# We will attempt to unshelve a change that is based on a change one commit
+# ahead of p4/master
+
+test_expect_success 'create shelved changelist based on p4 change ahead of p4/master' '
+	git p4 clone --dest="$git" //depot/@all &&
+	(
+		cd "$cli" &&
+		p4 revert ... &&
+		p4 edit file1 &&
+		echo "foo" >>file1 &&
+		p4 submit -d "change:foo" &&
+		p4 edit file1 &&
+		echo "bar" >>file1 &&
+		p4 shelve -i <<EOF &&
+Change: new
+Description:
+	Change to be unshelved
+Files:
+	//depot/file1
+EOF
+		change=$(last_shelved_change) &&
+		p4 describe -S $change | grep -q "Change to be unshelved"
+	)
+'
+
+# Now try to unshelve it. git-p4 should refuse to do so.
+test_expect_success 'try to unshelve the change' '
+	test_when_finished cleanup_git &&
+	(
+		change=$(last_shelved_change) &&
+		cd "$git" &&
+		test_must_fail git p4 unshelve $change 2>out.txt &&
+		grep -q "cannot unshelve" out.txt
+	)
+'
+
+test_expect_success 'kill p4d' '
+	kill_p4d
+'
+
+test_done
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index 1b34caa..a28640c 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -13,7 +13,7 @@
 	return 0
 }
 
-# Be careful when updating this list:
+# Be careful when updating these lists:
 #
 # (1) The build tree may have build artifact from different branch, or
 #     the user's $PATH may have a random executable that may begin
@@ -30,7 +30,8 @@
 #     completion for "git <TAB>", and a plumbing is excluded.  "add",
 #     "filter-branch" and "ls-files" are listed for this.
 
-GIT_TESTING_COMMAND_COMPLETION='add checkout check-attr filter-branch ls-files'
+GIT_TESTING_ALL_COMMAND_LIST='add checkout check-attr filter-branch ls-files'
+GIT_TESTING_PORCELAIN_COMMAND_LIST='add checkout filter-branch'
 
 . "$GIT_BUILD_DIR/contrib/completion/git-completion.bash"
 
@@ -84,10 +85,11 @@
 	then
 		printf '%s\n' "$2" >expected
 	else
-		sed -e 's/Z$//' >expected
+		sed -e 's/Z$//' |sort >expected
 	fi &&
 	run_completion "$1" &&
-	test_cmp expected out
+	sort out >out_sorted &&
+	test_cmp expected out_sorted
 }
 
 # Test __gitcomp.
@@ -179,7 +181,7 @@
 test_expect_success '__git_find_repo_path - parent is a .git directory' '
 	echo "$ROOT/.git" >expected &&
 	(
-		cd .git/refs/heads &&
+		cd .git/objects &&
 		__git_find_repo_path &&
 		echo "$__git_repo_path" >"$actual"
 	) &&
@@ -400,6 +402,46 @@
 	test_cmp expected "$actual"
 '
 
+
+test_expect_success '__git_dequote - plain unquoted word' '
+	__git_dequote unquoted-word &&
+	verbose test unquoted-word = "$dequoted_word"
+'
+
+# input:    b\a\c\k\'\\\"s\l\a\s\h\es
+# expected: back'\"slashes
+test_expect_success '__git_dequote - backslash escaped' '
+	__git_dequote "b\a\c\k\\'\''\\\\\\\"s\l\a\s\h\es" &&
+	verbose test "back'\''\\\"slashes" = "$dequoted_word"
+'
+
+# input:    sin'gle\' '"quo'ted
+# expected: single\ "quoted
+test_expect_success '__git_dequote - single quoted' '
+	__git_dequote "'"sin'gle\\\\' '\\\"quo'ted"'" &&
+	verbose test '\''single\ "quoted'\'' = "$dequoted_word"
+'
+
+# input:    dou"ble\\" "\"\quot"ed
+# expected: double\ "\quoted
+test_expect_success '__git_dequote - double quoted' '
+	__git_dequote '\''dou"ble\\" "\"\quot"ed'\'' &&
+	verbose test '\''double\ "\quoted'\'' = "$dequoted_word"
+'
+
+# input: 'open single quote
+test_expect_success '__git_dequote - open single quote' '
+	__git_dequote "'\''open single quote" &&
+	verbose test "open single quote" = "$dequoted_word"
+'
+
+# input: "open double quote
+test_expect_success '__git_dequote - open double quote' '
+	__git_dequote "\"open double quote" &&
+	verbose test "open double quote" = "$dequoted_word"
+'
+
+
 test_expect_success '__gitcomp_direct - puts everything into COMPREPLY as-is' '
 	sed -e "s/Z$//g" >expected <<-EOF &&
 	with-trailing-space Z
@@ -1168,6 +1210,124 @@
 	git remote remove other
 '
 
+
+test_path_completion ()
+{
+	test $# = 2 || error "bug in the test script: not 2 parameters to test_path_completion"
+
+	local cur="$1" expected="$2"
+	echo "$expected" >expected &&
+	(
+		# In the following tests calling this function we only
+		# care about how __git_complete_index_file() deals with
+		# unusual characters in path names.  By requesting only
+		# untracked files we dont have to bother adding any
+		# paths to the index in those tests.
+		__git_complete_index_file --others &&
+		print_comp
+	) &&
+	test_cmp expected out
+}
+
+test_expect_success 'setup for path completion tests' '
+	mkdir simple-dir \
+	      "spaces in dir" \
+	      árvíztűrő &&
+	touch simple-dir/simple-file \
+	      "spaces in dir/spaces in file" \
+	      "árvíztűrő/Сайн яваарай" &&
+	if test_have_prereq !MINGW &&
+	   mkdir BS\\dir \
+		 '$'separators\034in\035dir'' &&
+	   touch BS\\dir/DQ\"file \
+		 '$'separators\034in\035dir/sep\036in\037file''
+	then
+		test_set_prereq FUNNYNAMES
+	else
+		rm -rf BS\\dir '$'separators\034in\035dir''
+	fi
+'
+
+test_expect_success '__git_complete_index_file - simple' '
+	test_path_completion simple simple-dir &&  # Bash is supposed to
+						   # add the trailing /.
+	test_path_completion simple-dir/simple simple-dir/simple-file
+'
+
+test_expect_success \
+    '__git_complete_index_file - escaped characters on cmdline' '
+	test_path_completion spac "spaces in dir" &&  # Bash will turn this
+						      # into "spaces\ in\ dir"
+	test_path_completion "spaces\\ i" \
+			     "spaces in dir" &&
+	test_path_completion "spaces\\ in\\ dir/s" \
+			     "spaces in dir/spaces in file" &&
+	test_path_completion "spaces\\ in\\ dir/spaces\\ i" \
+			     "spaces in dir/spaces in file"
+'
+
+test_expect_success \
+    '__git_complete_index_file - quoted characters on cmdline' '
+	# Testing with an opening but without a corresponding closing
+	# double quote is important.
+	test_path_completion \"spac "spaces in dir" &&
+	test_path_completion "\"spaces i" \
+			     "spaces in dir" &&
+	test_path_completion "\"spaces in dir/s" \
+			     "spaces in dir/spaces in file" &&
+	test_path_completion "\"spaces in dir/spaces i" \
+			     "spaces in dir/spaces in file"
+'
+
+test_expect_success '__git_complete_index_file - UTF-8 in ls-files output' '
+	test_path_completion á árvíztűrő &&
+	test_path_completion árvíztűrő/С "árvíztűrő/Сайн яваарай"
+'
+
+test_expect_success FUNNYNAMES \
+    '__git_complete_index_file - C-style escapes in ls-files output' '
+	test_path_completion BS \
+			     BS\\dir &&
+	test_path_completion BS\\\\d \
+			     BS\\dir &&
+	test_path_completion BS\\\\dir/DQ \
+			     BS\\dir/DQ\"file &&
+	test_path_completion BS\\\\dir/DQ\\\"f \
+			     BS\\dir/DQ\"file
+'
+
+test_expect_success FUNNYNAMES \
+    '__git_complete_index_file - \nnn-escaped characters in ls-files output' '
+	test_path_completion sep '$'separators\034in\035dir'' &&
+	test_path_completion '$'separators\034i'' \
+			     '$'separators\034in\035dir'' &&
+	test_path_completion '$'separators\034in\035dir/sep'' \
+			     '$'separators\034in\035dir/sep\036in\037file'' &&
+	test_path_completion '$'separators\034in\035dir/sep\036i'' \
+			     '$'separators\034in\035dir/sep\036in\037file''
+'
+
+test_expect_success FUNNYNAMES \
+    '__git_complete_index_file - removing repeated quoted path components' '
+	test_when_finished rm -r repeated-quoted &&
+	mkdir repeated-quoted &&      # A directory whose name in itself
+				      # would not be quoted ...
+	>repeated-quoted/0-file &&
+	>repeated-quoted/1\"file &&   # ... but here the file makes the
+				      # dirname quoted ...
+	>repeated-quoted/2-file &&
+	>repeated-quoted/3\"file &&   # ... and here, too.
+
+	# Still, we shold only list the directory name only once.
+	test_path_completion repeated repeated-quoted
+'
+
+test_expect_success 'teardown after path completion tests' '
+	rm -rf simple-dir "spaces in dir" árvíztűrő \
+	       BS\\dir '$'separators\034in\035dir''
+'
+
+
 test_expect_success '__git_get_config_variables' '
 	cat >expect <<-EOF &&
 	name-1
@@ -1191,17 +1351,6 @@
 	test_cmp expect actual
 '
 
-test_expect_success '__git_aliases' '
-	cat >expect <<-EOF &&
-	ci
-	co
-	EOF
-	test_config alias.ci commit &&
-	test_config alias.co checkout &&
-	__git_aliases >actual &&
-	test_cmp expect actual
-'
-
 test_expect_success 'basic' '
 	run_completion "git " &&
 	# built-in
@@ -1365,6 +1514,7 @@
 
 	echo "expected" > .gitignore &&
 	echo "out" >> .gitignore &&
+	echo "out_sorted" >> .gitignore &&
 
 	git add .gitignore &&
 	test_completion "git commit " ".gitignore" &&
@@ -1510,13 +1660,6 @@
 	verbose test -z "$__git_all_commands"
 '
 
-test_expect_success 'sourcing the completion script clears cached porcelain commands' '
-	__git_compute_porcelain_commands &&
-	verbose test -n "$__git_porcelain_commands" &&
-	. "$GIT_BUILD_DIR/contrib/completion/git-completion.bash" &&
-	verbose test -z "$__git_porcelain_commands"
-'
-
 test_expect_success !GETTEXT_POISON 'sourcing the completion script clears cached merge strategies' '
 	__git_compute_merge_strategies &&
 	verbose test -n "$__git_merge_strategies" &&
diff --git a/t/t9903-bash-prompt.sh b/t/t9903-bash-prompt.sh
index 8f5c811..c3b89ae 100755
--- a/t/t9903-bash-prompt.sh
+++ b/t/t9903-bash-prompt.sh
@@ -148,7 +148,7 @@
 test_expect_success 'prompt - deep inside .git directory' '
 	printf " (GIT_DIR!)" >expected &&
 	(
-		cd .git/refs/heads &&
+		cd .git/objects &&
 		__git_ps1 >"$actual"
 	) &&
 	test_cmp expected "$actual"
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 7d620bf..2b2181d 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -145,12 +145,28 @@
 	"$SHELL_PATH" <&6 >&5 2>&7
 }
 
-# Wrap git in gdb. Adding this to a command can make it easier to
-# understand what is going on in a failing test.
+# Wrap git with a debugger. Adding this to a command can make it easier
+# to understand what is going on in a failing test.
 #
-# Example: "debug git checkout master".
+# Examples:
+#     debug git checkout master
+#     debug --debugger=nemiver git $ARGS
+#     debug -d "valgrind --tool=memcheck --track-origins=yes" git $ARGS
 debug () {
-	 GIT_TEST_GDB=1 "$@" <&6 >&5 2>&7
+	case "$1" in
+	-d)
+		GIT_DEBUGGER="$2" &&
+		shift 2
+		;;
+	--debugger=*)
+		GIT_DEBUGGER="${1#*=}" &&
+		shift 1
+		;;
+	*)
+		GIT_DEBUGGER=1
+		;;
+	esac &&
+	GIT_DEBUGGER="${GIT_DEBUGGER}" "$@" <&6 >&5 2>&7
 }
 
 # Call test_commit with the arguments
@@ -278,8 +294,20 @@
 # The single parameter is the prerequisite tag (a simple word, in all
 # capital letters by convention).
 
+test_unset_prereq () {
+	! test_have_prereq "$1" ||
+	satisfied_prereq="${satisfied_prereq% $1 *} ${satisfied_prereq#* $1 }"
+}
+
 test_set_prereq () {
-	satisfied_prereq="$satisfied_prereq$1 "
+	case "$1" in
+	!*)
+		test_unset_prereq "${1#!}"
+		;;
+	*)
+		satisfied_prereq="$satisfied_prereq$1 "
+		;;
+	esac
 }
 satisfied_prereq=" "
 lazily_testable_prereq= lazily_tested_prereq=
diff --git a/t/test-lib.sh b/t/test-lib.sh
index ea2bbaa..2831570 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -184,6 +184,8 @@
 # Zero SHA-1
 _z40=0000000000000000000000000000000000000000
 
+OID_REGEX="$_x40"
+ZERO_OID=$_z40
 EMPTY_TREE=4b825dc642cb6eb9a060e54bf8d69288fbee4904
 EMPTY_BLOB=e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
 
@@ -195,7 +197,7 @@
 # when case-folding filenames
 u200c=$(printf '\342\200\214')
 
-export _x05 _x35 _x40 _z40 LF u200c EMPTY_TREE EMPTY_BLOB
+export _x05 _x35 _x40 _z40 LF u200c EMPTY_TREE EMPTY_BLOB ZERO_OID OID_REGEX
 
 # Each test should start with something like this, after copyright notices:
 #
@@ -1106,12 +1108,7 @@
 	auml=$(printf "\303\244")
 	aumlcdiar=$(printf "\141\314\210")
 	>"$auml" &&
-	case "$(echo *)" in
-	"$aumlcdiar")
-		true ;;
-	*)
-		false ;;
-	esac
+	test -f "$aumlcdiar"
 '
 
 test_lazy_prereq AUTOIDENT '
@@ -1212,3 +1209,10 @@
 test_lazy_prereq CURL '
 	curl --version
 '
+
+# SHA1 is a test if the hash algorithm in use is SHA-1.  This is both for tests
+# which will not work with other hash algorithms and tests that work but don't
+# test anything meaningful (e.g. special values which cause short collisions).
+test_lazy_prereq SHA1 '
+	test $(git hash-object /dev/null) = e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
+'
diff --git a/tag.c b/tag.c
index 86b1dcb..3d37c1b 100644
--- a/tag.c
+++ b/tag.c
@@ -41,7 +41,7 @@
 	unsigned long size;
 	int ret;
 
-	type = oid_object_info(oid, NULL);
+	type = oid_object_info(the_repository, oid, NULL);
 	if (type != OBJ_TAG)
 		return error("%s: cannot verify a non-tag object of type %s.",
 				name_to_report ?
diff --git a/templates/hooks--pre-commit.sample b/templates/hooks--pre-commit.sample
index 68d62d5..6a75641 100755
--- a/templates/hooks--pre-commit.sample
+++ b/templates/hooks--pre-commit.sample
@@ -12,7 +12,7 @@
 	against=HEAD
 else
 	# Initial commit: diff against an empty tree object
-	against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
+	against=$(git hash-object -t tree /dev/null)
 fi
 
 # If you want to allow non-ASCII filenames set this variable to true.
diff --git a/tmp-objdir.c b/tmp-objdir.c
index fea3f55..91c0056 100644
--- a/tmp-objdir.c
+++ b/tmp-objdir.c
@@ -127,7 +127,7 @@
 	struct tmp_objdir *t;
 
 	if (the_tmp_objdir)
-		die("BUG: only one tmp_objdir can be used at a time");
+		BUG("only one tmp_objdir can be used at a time");
 
 	t = xmalloc(sizeof(*t));
 	strbuf_init(&t->path, 0);
diff --git a/trailer.c b/trailer.c
index c508c9b..4e30946 100644
--- a/trailer.c
+++ b/trailer.c
@@ -298,7 +298,7 @@
 			free_arg_item(arg_tok);
 		break;
 	default:
-		die("BUG: trailer.c: unhandled value %d",
+		BUG("trailer.c: unhandled value %d",
 		    arg_tok->conf.if_exists);
 	}
 }
@@ -323,7 +323,7 @@
 			list_add(&to_add->list, head);
 		break;
 	default:
-		die("BUG: trailer.c: unhandled value %d",
+		BUG("trailer.c: unhandled value %d",
 		    arg_tok->conf.if_missing);
 	}
 }
@@ -557,7 +557,7 @@
 			warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 		break;
 	default:
-		die("BUG: trailer.c: unhandled type %d", type);
+		BUG("trailer.c: unhandled type %d", type);
 	}
 	return 0;
 }
diff --git a/transport-helper.c b/transport-helper.c
index 3f380d8..1f8ff7e 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -11,7 +11,9 @@
 #include "sigchain.h"
 #include "argv-array.h"
 #include "refs.h"
+#include "refspec.h"
 #include "transport-internal.h"
+#include "protocol.h"
 
 static int debug;
 
@@ -26,6 +28,7 @@
 		option : 1,
 		push : 1,
 		connect : 1,
+		stateless_connect : 1,
 		signed_tags : 1,
 		check_connectivity : 1,
 		no_disconnect_req : 1,
@@ -33,8 +36,7 @@
 	char *export_marks;
 	char *import_marks;
 	/* These go from remote name (as in "list") to private name */
-	struct refspec *refspecs;
-	int refspec_nr;
+	struct refspec rs;
 	/* Transport options for fetch-pack/send-pack (should one of
 	 * those be invoked).
 	 */
@@ -49,7 +51,7 @@
 		die_errno("Full write to remote helper failed");
 }
 
-static int recvline_fh(FILE *helper, struct strbuf *buffer, const char *name)
+static int recvline_fh(FILE *helper, struct strbuf *buffer)
 {
 	strbuf_reset(buffer);
 	if (debug)
@@ -67,7 +69,7 @@
 
 static int recvline(struct helper_data *helper, struct strbuf *buffer)
 {
-	return recvline_fh(helper->out, buffer, helper->name);
+	return recvline_fh(helper->out, buffer);
 }
 
 static void write_constant(int fd, const char *str)
@@ -104,9 +106,6 @@
 	struct helper_data *data = transport->data;
 	struct strbuf buf = STRBUF_INIT;
 	struct child_process *helper;
-	const char **refspecs = NULL;
-	int refspec_nr = 0;
-	int refspec_alloc = 0;
 	int duped;
 	int code;
 
@@ -136,6 +135,7 @@
 
 	data->helper = helper;
 	data->no_disconnect_req = 0;
+	refspec_init(&data->rs, REFSPEC_FETCH);
 
 	/*
 	 * Open the output as FILE* so strbuf_getline_*() family of
@@ -181,13 +181,12 @@
 			data->export = 1;
 		else if (!strcmp(capname, "check-connectivity"))
 			data->check_connectivity = 1;
-		else if (!data->refspecs && skip_prefix(capname, "refspec ", &arg)) {
-			ALLOC_GROW(refspecs,
-				   refspec_nr + 1,
-				   refspec_alloc);
-			refspecs[refspec_nr++] = xstrdup(arg);
+		else if (skip_prefix(capname, "refspec ", &arg)) {
+			refspec_append(&data->rs, arg);
 		} else if (!strcmp(capname, "connect")) {
 			data->connect = 1;
+		} else if (!strcmp(capname, "stateless-connect")) {
+			data->stateless_connect = 1;
 		} else if (!strcmp(capname, "signed-tags")) {
 			data->signed_tags = 1;
 		} else if (skip_prefix(capname, "export-marks ", &arg)) {
@@ -202,14 +201,7 @@
 			    capname);
 		}
 	}
-	if (refspecs) {
-		int i;
-		data->refspec_nr = refspec_nr;
-		data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
-		for (i = 0; i < refspec_nr; i++)
-			free((char *)refspecs[i]);
-		free(refspecs);
-	} else if (data->import || data->bidi_import || data->export) {
+	if (!data->rs.nr && (data->import || data->bidi_import || data->export)) {
 		warning("This remote helper should implement refspec capability.");
 	}
 	strbuf_release(&buf);
@@ -373,8 +365,7 @@
 {
 	int res = 0;
 	struct helper_data *data = transport->data;
-	free_refspec(data->refspec_nr, data->refspecs);
-	data->refspecs = NULL;
+	refspec_clear(&data->rs);
 	res = disconnect_helper(transport);
 	free(transport->data);
 	return res;
@@ -531,8 +522,8 @@
 		if (posn->status & REF_STATUS_UPTODATE)
 			continue;
 		name = posn->symref ? posn->symref : posn->name;
-		if (data->refspecs)
-			private = apply_refspecs(data->refspecs, data->refspec_nr, name);
+		if (data->rs.nr)
+			private = apply_refspecs(&data->rs, name);
 		else
 			private = xstrdup(name);
 		if (private) {
@@ -545,14 +536,13 @@
 	return 0;
 }
 
-static int process_connect_service(struct transport *transport,
-				   const char *name, const char *exec)
+static int run_connect(struct transport *transport, struct strbuf *cmdbuf)
 {
 	struct helper_data *data = transport->data;
-	struct strbuf cmdbuf = STRBUF_INIT;
-	struct child_process *helper;
-	int r, duped, ret = 0;
+	int ret = 0;
+	int duped;
 	FILE *input;
+	struct child_process *helper;
 
 	helper = get_helper(transport);
 
@@ -568,44 +558,61 @@
 	input = xfdopen(duped, "r");
 	setvbuf(input, NULL, _IONBF, 0);
 
+	sendline(data, cmdbuf);
+	if (recvline_fh(input, cmdbuf))
+		exit(128);
+
+	if (!strcmp(cmdbuf->buf, "")) {
+		data->no_disconnect_req = 1;
+		if (debug)
+			fprintf(stderr, "Debug: Smart transport connection "
+				"ready.\n");
+		ret = 1;
+	} else if (!strcmp(cmdbuf->buf, "fallback")) {
+		if (debug)
+			fprintf(stderr, "Debug: Falling back to dumb "
+				"transport.\n");
+	} else {
+		die("Unknown response to connect: %s",
+			cmdbuf->buf);
+	}
+
+	fclose(input);
+	return ret;
+}
+
+static int process_connect_service(struct transport *transport,
+				   const char *name, const char *exec)
+{
+	struct helper_data *data = transport->data;
+	struct strbuf cmdbuf = STRBUF_INIT;
+	int ret = 0;
+
 	/*
 	 * Handle --upload-pack and friends. This is fire and forget...
 	 * just warn if it fails.
 	 */
 	if (strcmp(name, exec)) {
-		r = set_helper_option(transport, "servpath", exec);
+		int r = set_helper_option(transport, "servpath", exec);
 		if (r > 0)
 			warning("Setting remote service path not supported by protocol.");
 		else if (r < 0)
 			warning("Invalid remote service path.");
 	}
 
-	if (data->connect)
+	if (data->connect) {
 		strbuf_addf(&cmdbuf, "connect %s\n", name);
-	else
-		goto exit;
+		ret = run_connect(transport, &cmdbuf);
+	} else if (data->stateless_connect &&
+		   (get_protocol_version_config() == protocol_v2) &&
+		   !strcmp("git-upload-pack", name)) {
+		strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
+		ret = run_connect(transport, &cmdbuf);
+		if (ret)
+			transport->stateless_rpc = 1;
+	}
 
-	sendline(data, &cmdbuf);
-	if (recvline_fh(input, &cmdbuf, name))
-		exit(128);
-
-	if (!strcmp(cmdbuf.buf, "")) {
-		data->no_disconnect_req = 1;
-		if (debug)
-			fprintf(stderr, "Debug: Smart transport connection "
-				"ready.\n");
-		ret = 1;
-	} else if (!strcmp(cmdbuf.buf, "fallback")) {
-		if (debug)
-			fprintf(stderr, "Debug: Falling back to dumb "
-				"transport.\n");
-	} else
-		die("Unknown response to connect: %s",
-			cmdbuf.buf);
-
-exit:
 	strbuf_release(&cmdbuf);
-	fclose(input);
 	return ret;
 }
 
@@ -794,11 +801,11 @@
 		if (push_update_ref_status(&buf, &ref, remote_refs))
 			continue;
 
-		if (flags & TRANSPORT_PUSH_DRY_RUN || !data->refspecs || data->no_private_update)
+		if (flags & TRANSPORT_PUSH_DRY_RUN || !data->rs.nr || data->no_private_update)
 			continue;
 
 		/* propagate back the update to the remote namespace */
-		private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
+		private = apply_refspecs(&data->rs, ref->name);
 		if (!private)
 			continue;
 		update_ref("update by helper", private, &ref->new_oid, NULL,
@@ -918,7 +925,7 @@
 	struct string_list revlist_args = STRING_LIST_INIT_DUP;
 	struct strbuf buf = STRBUF_INIT;
 
-	if (!data->refspecs)
+	if (!data->rs.nr)
 		die("remote-helper doesn't support push; refspec needed");
 
 	set_common_push_options(transport, data->name, flags);
@@ -935,7 +942,7 @@
 		char *private;
 		struct object_id oid;
 
-		private = apply_refspecs(data->refspecs, data->refspec_nr, ref->name);
+		private = apply_refspecs(&data->rs, ref->name);
 		if (private && !get_oid(private, &oid)) {
 			strbuf_addf(&buf, "^%s", private);
 			string_list_append_nodup(&revlist_args,
@@ -1031,7 +1038,8 @@
 	}
 }
 
-static struct ref *get_refs_list(struct transport *transport, int for_push)
+static struct ref *get_refs_list(struct transport *transport, int for_push,
+				 const struct argv_array *ref_prefixes)
 {
 	struct helper_data *data = transport->data;
 	struct child_process *helper;
@@ -1044,7 +1052,7 @@
 
 	if (process_connect(transport, for_push)) {
 		do_take_over(transport);
-		return transport->vtable->get_refs_list(transport, for_push);
+		return transport->vtable->get_refs_list(transport, for_push, ref_prefixes);
 	}
 
 	if (data->push && for_push)
diff --git a/transport-internal.h b/transport-internal.h
index 3c1a29d..1cde625 100644
--- a/transport-internal.h
+++ b/transport-internal.h
@@ -3,6 +3,7 @@
 
 struct ref;
 struct transport;
+struct argv_array;
 
 struct transport_vtable {
 	/**
@@ -17,11 +18,19 @@
 	 * the transport to try to share connections, for_push is a
 	 * hint as to whether the ultimate operation is a push or a fetch.
 	 *
+	 * If communicating using protocol v2 a list of prefixes can be
+	 * provided to be sent to the server to enable it to limit the ref
+	 * advertisement.  Since ref filtering is done on the server's end, and
+	 * only when using protocol v2, this list will be ignored when not
+	 * using protocol v2 meaning this function can return refs which don't
+	 * match the provided ref_prefixes.
+	 *
 	 * If the transport is able to determine the remote hash for
 	 * the ref without a huge amount of effort, it should store it
 	 * in the ref's old_sha1 field; otherwise it should be all 0.
 	 **/
-	struct ref *(*get_refs_list)(struct transport *transport, int for_push);
+	struct ref *(*get_refs_list)(struct transport *transport, int for_push,
+				     const struct argv_array *ref_prefixes);
 
 	/**
 	 * Fetch the objects for the given refs. Note that this gets
diff --git a/transport.c b/transport.c
index 94eccf2..a32da30 100644
--- a/transport.c
+++ b/transport.c
@@ -11,6 +11,7 @@
 #include "bundle.h"
 #include "dir.h"
 #include "refs.h"
+#include "refspec.h"
 #include "branch.h"
 #include "url.h"
 #include "submodule.h"
@@ -18,7 +19,58 @@
 #include "sha1-array.h"
 #include "sigchain.h"
 #include "transport-internal.h"
+#include "protocol.h"
 #include "object-store.h"
+#include "color.h"
+
+static int transport_use_color = -1;
+static char transport_colors[][COLOR_MAXLEN] = {
+	GIT_COLOR_RESET,
+	GIT_COLOR_RED		/* REJECTED */
+};
+
+enum color_transport {
+	TRANSPORT_COLOR_RESET = 0,
+	TRANSPORT_COLOR_REJECTED = 1
+};
+
+static int transport_color_config(void)
+{
+	const char *keys[] = {
+		"color.transport.reset",
+		"color.transport.rejected"
+	}, *key = "color.transport";
+	char *value;
+	int i;
+	static int initialized;
+
+	if (initialized)
+		return 0;
+	initialized = 1;
+
+	if (!git_config_get_string(key, &value))
+		transport_use_color = git_config_colorbool(key, value);
+
+	if (!want_color_stderr(transport_use_color))
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(keys); i++)
+		if (!git_config_get_string(keys[i], &value)) {
+			if (!value)
+				return config_error_nonbool(keys[i]);
+			if (color_parse(value, transport_colors[i]) < 0)
+				return -1;
+		}
+
+	return 0;
+}
+
+static const char *transport_get_color(enum color_transport ix)
+{
+	if (want_color_stderr(transport_use_color))
+		return transport_colors[ix];
+	return "";
+}
 
 static void set_upstreams(struct transport *transport, struct ref *refs,
 	int pretend)
@@ -72,7 +124,9 @@
 	struct bundle_header header;
 };
 
-static struct ref *get_refs_from_bundle(struct transport *transport, int for_push)
+static struct ref *get_refs_from_bundle(struct transport *transport,
+					int for_push,
+					const struct argv_array *ref_prefixes)
 {
 	struct bundle_transport_data *data = transport->data;
 	struct ref *result = NULL;
@@ -118,6 +172,7 @@
 	struct child_process *conn;
 	int fd[2];
 	unsigned got_remote_heads : 1;
+	enum protocol_version version;
 	struct oid_array extra_have;
 	struct oid_array shallow;
 };
@@ -197,16 +252,35 @@
 	return 0;
 }
 
-static struct ref *get_refs_via_connect(struct transport *transport, int for_push)
+static struct ref *get_refs_via_connect(struct transport *transport, int for_push,
+					const struct argv_array *ref_prefixes)
 {
 	struct git_transport_data *data = transport->data;
-	struct ref *refs;
+	struct ref *refs = NULL;
+	struct packet_reader reader;
 
 	connect_setup(transport, for_push);
-	get_remote_heads(data->fd[0], NULL, 0, &refs,
-			 for_push ? REF_NORMAL : 0,
-			 &data->extra_have,
-			 &data->shallow);
+
+	packet_reader_init(&reader, data->fd[0], NULL, 0,
+			   PACKET_READ_CHOMP_NEWLINE |
+			   PACKET_READ_GENTLE_ON_EOF);
+
+	data->version = discover_version(&reader);
+	switch (data->version) {
+	case protocol_v2:
+		get_remote_refs(data->fd[1], &reader, &refs, for_push,
+				ref_prefixes, transport->server_options);
+		break;
+	case protocol_v1:
+	case protocol_v0:
+		get_remote_heads(&reader, &refs,
+				 for_push ? REF_NORMAL : 0,
+				 &data->extra_have,
+				 &data->shallow);
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
+	}
 	data->got_remote_heads = 1;
 
 	return refs;
@@ -217,7 +291,7 @@
 {
 	int ret = 0;
 	struct git_transport_data *data = transport->data;
-	struct ref *refs;
+	struct ref *refs = NULL;
 	char *dest = xstrdup(transport->url);
 	struct fetch_pack_args args;
 	struct ref *refs_tmp = NULL;
@@ -242,18 +316,30 @@
 	args.from_promisor = data->options.from_promisor;
 	args.no_dependents = data->options.no_dependents;
 	args.filter_options = data->options.filter_options;
+	args.stateless_rpc = transport->stateless_rpc;
+	args.server_options = transport->server_options;
 
-	if (!data->got_remote_heads) {
-		connect_setup(transport, 0);
-		get_remote_heads(data->fd[0], NULL, 0, &refs_tmp, 0,
-				 NULL, &data->shallow);
-		data->got_remote_heads = 1;
+	if (!data->got_remote_heads)
+		refs_tmp = get_refs_via_connect(transport, 0, NULL);
+
+	switch (data->version) {
+	case protocol_v2:
+		refs = fetch_pack(&args, data->fd, data->conn,
+				  refs_tmp ? refs_tmp : transport->remote_refs,
+				  dest, to_fetch, nr_heads, &data->shallow,
+				  &transport->pack_lockfile, data->version);
+		break;
+	case protocol_v1:
+	case protocol_v0:
+		refs = fetch_pack(&args, data->fd, data->conn,
+				  refs_tmp ? refs_tmp : transport->remote_refs,
+				  dest, to_fetch, nr_heads, &data->shallow,
+				  &transport->pack_lockfile, data->version);
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
 	}
 
-	refs = fetch_pack(&args, data->fd, data->conn,
-			  refs_tmp ? refs_tmp : transport->remote_refs,
-			  dest, to_fetch, nr_heads, &data->shallow,
-			  &transport->pack_lockfile);
 	close(data->fd[0]);
 	close(data->fd[1]);
 	if (finish_connect(data->conn))
@@ -305,7 +391,7 @@
 
 void transport_update_tracking_ref(struct remote *remote, struct ref *ref, int verbose)
 {
-	struct refspec rs;
+	struct refspec_item rs;
 
 	if (ref->status != REF_STATUS_OK && ref->status != REF_STATUS_UPTODATE)
 		return;
@@ -339,7 +425,13 @@
 		else
 			fprintf(stdout, "%s\n", summary);
 	} else {
-		fprintf(stderr, " %c %-*s ", flag, summary_width, summary);
+		const char *red = "", *reset = "";
+		if (push_had_errors(to)) {
+			red = transport_get_color(TRANSPORT_COLOR_REJECTED);
+			reset = transport_get_color(TRANSPORT_COLOR_RESET);
+		}
+		fprintf(stderr, " %s%c %-*s%s ", red, flag, summary_width,
+			summary, reset);
 		if (from)
 			fprintf(stderr, "%s -> %s", prettify_refname(from->name), prettify_refname(to->name));
 		else
@@ -488,6 +580,9 @@
 	char *head;
 	int summary_width = transport_summary_width(refs);
 
+	if (transport_color_config() < 0)
+		warning(_("could not parse transport.color.* config"));
+
 	head = resolve_refdup("HEAD", RESOLVE_REF_READING, NULL, NULL);
 
 	if (verbose) {
@@ -525,43 +620,17 @@
 	free(head);
 }
 
-void transport_verify_remote_names(int nr_heads, const char **heads)
-{
-	int i;
-
-	for (i = 0; i < nr_heads; i++) {
-		const char *local = heads[i];
-		const char *remote = strrchr(heads[i], ':');
-
-		if (*local == '+')
-			local++;
-
-		/* A matching refspec is okay.  */
-		if (remote == local && remote[1] == '\0')
-			continue;
-
-		remote = remote ? (remote + 1) : local;
-		if (check_refname_format(remote,
-				REFNAME_ALLOW_ONELEVEL|REFNAME_REFSPEC_PATTERN))
-			die("remote part of refspec is not a valid name in %s",
-				heads[i]);
-	}
-}
-
 static int git_transport_push(struct transport *transport, struct ref *remote_refs, int flags)
 {
 	struct git_transport_data *data = transport->data;
 	struct send_pack_args args;
-	int ret;
+	int ret = 0;
 
-	if (!data->got_remote_heads) {
-		struct ref *tmp_refs;
-		connect_setup(transport, 1);
+	if (transport_color_config() < 0)
+		return -1;
 
-		get_remote_heads(data->fd[0], NULL, 0, &tmp_refs, REF_NORMAL,
-				 NULL, &data->shallow);
-		data->got_remote_heads = 1;
-	}
+	if (!data->got_remote_heads)
+		get_refs_via_connect(transport, 1, NULL);
 
 	memset(&args, 0, sizeof(args));
 	args.send_mirror = !!(flags & TRANSPORT_PUSH_MIRROR);
@@ -583,8 +652,18 @@
 	else
 		args.push_cert = SEND_PACK_PUSH_CERT_NEVER;
 
-	ret = send_pack(&args, data->fd, data->conn, remote_refs,
-			&data->extra_have);
+	switch (data->version) {
+	case protocol_v2:
+		die("support for protocol v2 not implemented yet");
+		break;
+	case protocol_v1:
+	case protocol_v0:
+		ret = send_pack(&args, data->fd, data->conn, remote_refs,
+				&data->extra_have);
+		break;
+	case protocol_unknown_version:
+		BUG("unknown protocol version");
+	}
 
 	close(data->fd[1]);
 	close(data->fd[0]);
@@ -636,7 +715,7 @@
 	struct git_transport_data *data;
 
 	if (!transport->smart_options)
-		die("BUG: taking over transport requires non-NULL "
+		BUG("taking over transport requires non-NULL "
 		    "smart_options field.");
 
 	data = xcalloc(1, sizeof(*data));
@@ -761,7 +840,7 @@
 		return from_user;
 	}
 
-	die("BUG: invalid protocol_allow_config type");
+	BUG("invalid protocol_allow_config type");
 }
 
 void transport_check_allowed(const char *type)
@@ -992,11 +1071,13 @@
 }
 
 int transport_push(struct transport *transport,
-		   int refspec_nr, const char **refspec, int flags,
+		   struct refspec *rs, int flags,
 		   unsigned int *reject_reasons)
 {
 	*reject_reasons = 0;
-	transport_verify_remote_names(refspec_nr, refspec);
+
+	if (transport_color_config() < 0)
+		return -1;
 
 	if (transport->vtable->push_refs) {
 		struct ref *remote_refs;
@@ -1007,11 +1088,17 @@
 		int porcelain = flags & TRANSPORT_PUSH_PORCELAIN;
 		int pretend = flags & TRANSPORT_PUSH_DRY_RUN;
 		int push_ret, ret, err;
+		struct argv_array ref_prefixes = ARGV_ARRAY_INIT;
 
-		if (check_push_refs(local_refs, refspec_nr, refspec) < 0)
+		if (check_push_refs(local_refs, rs) < 0)
 			return -1;
 
-		remote_refs = transport->vtable->get_refs_list(transport, 1);
+		refspec_ref_prefixes(rs, &ref_prefixes);
+
+		remote_refs = transport->vtable->get_refs_list(transport, 1,
+							       &ref_prefixes);
+
+		argv_array_clear(&ref_prefixes);
 
 		if (flags & TRANSPORT_PUSH_ALL)
 			match_flags |= MATCH_REFS_ALL;
@@ -1022,10 +1109,8 @@
 		if (flags & TRANSPORT_PUSH_FOLLOW_TAGS)
 			match_flags |= MATCH_REFS_FOLLOW_TAGS;
 
-		if (match_push_refs(local_refs, &remote_refs,
-				    refspec_nr, refspec, match_flags)) {
+		if (match_push_refs(local_refs, &remote_refs, rs, match_flags))
 			return -1;
-		}
 
 		if (transport->smart_options &&
 		    transport->smart_options->cas &&
@@ -1054,7 +1139,7 @@
 
 			if (!push_unpushed_submodules(&commits,
 						      transport->remote,
-						      refspec, refspec_nr,
+						      rs,
 						      transport->push_options,
 						      pretend)) {
 				oid_array_clear(&commits);
@@ -1117,10 +1202,13 @@
 	return 1;
 }
 
-const struct ref *transport_get_remote_refs(struct transport *transport)
+const struct ref *transport_get_remote_refs(struct transport *transport,
+					    const struct argv_array *ref_prefixes)
 {
 	if (!transport->got_remote_refs) {
-		transport->remote_refs = transport->vtable->get_refs_list(transport, 0);
+		transport->remote_refs =
+			transport->vtable->get_refs_list(transport, 0,
+							 ref_prefixes);
 		transport->got_remote_refs = 1;
 	}
 
diff --git a/transport.h b/transport.h
index 3c68d73..7792b08 100644
--- a/transport.h
+++ b/transport.h
@@ -60,11 +60,23 @@
 	unsigned cloning : 1;
 
 	/*
+	 * Indicates that the transport is connected via a half-duplex
+	 * connection and should operate in stateless-rpc mode.
+	 */
+	unsigned stateless_rpc : 1;
+
+	/*
 	 * These strings will be passed to the {pre, post}-receive hook,
 	 * on the remote side, if both sides support the push options capability.
 	 */
 	const struct string_list *push_options;
 
+	/*
+	 * These strings will be passed to the remote side on each command
+	 * request, if both sides support the server-option capability.
+	 */
+	const struct string_list *server_options;
+
 	char *pack_lockfile;
 	signed verbose : 3;
 	/**
@@ -191,10 +203,20 @@
 #define REJECT_NEEDS_FORCE     0x10
 
 int transport_push(struct transport *connection,
-		   int refspec_nr, const char **refspec, int flags,
+		   struct refspec *rs, int flags,
 		   unsigned int * reject_reasons);
 
-const struct ref *transport_get_remote_refs(struct transport *transport);
+/*
+ * Retrieve refs from a remote.
+ *
+ * Optionally a list of ref prefixes can be provided which can be sent to the
+ * server (when communicating using protocol v2) to enable it to limit the ref
+ * advertisement.  Since ref filtering is done on the server's end (and only
+ * when using protocol v2), this can return refs which don't match the provided
+ * ref_prefixes.
+ */
+const struct ref *transport_get_remote_refs(struct transport *transport,
+					    const struct argv_array *ref_prefixes);
 
 int transport_fetch_refs(struct transport *transport, struct ref *refs);
 void transport_unlock_pack(struct transport *transport);
@@ -211,8 +233,6 @@
 int bidirectional_transfer_loop(int input, int output);
 
 /* common methods used by transport.c and builtin/send-pack.c */
-void transport_verify_remote_names(int nr_heads, const char **heads);
-
 void transport_update_tracking_ref(struct remote *remote, struct ref *ref, int verbose);
 
 int transport_refs_pushed(struct ref *ref);
diff --git a/tree-walk.c b/tree-walk.c
index e11b306..8f50908 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -105,7 +105,7 @@
 static int update_tree_entry_internal(struct tree_desc *desc, struct strbuf *err)
 {
 	const void *buf = desc->buffer;
-	const unsigned char *end = desc->entry.oid->hash + 20;
+	const unsigned char *end = desc->entry.oid->hash + the_hash_algo->rawsz;
 	unsigned long size = desc->size;
 	unsigned long len = end - (const unsigned char *)buf;
 
@@ -488,7 +488,7 @@
 struct dir_state {
 	void *tree;
 	unsigned long size;
-	unsigned char sha1[20];
+	struct object_id oid;
 };
 
 static int find_tree_entry(struct tree_desc *t, const char *name, struct object_id *result, unsigned *mode)
@@ -576,7 +576,7 @@
  * See the code for enum follow_symlink_result for a description of
  * the return values.
  */
-enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_sha1, const char *name, unsigned char *result, struct strbuf *result_path, unsigned *mode)
+enum follow_symlinks_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned *mode)
 {
 	int retval = MISSING_OBJECT;
 	struct dir_state *parents = NULL;
@@ -589,7 +589,7 @@
 
 	init_tree_desc(&t, NULL, 0UL);
 	strbuf_addstr(&namebuf, name);
-	hashcpy(current_tree_oid.hash, tree_sha1);
+	oidcpy(&current_tree_oid, tree_oid);
 
 	while (1) {
 		int find_result;
@@ -609,11 +609,11 @@
 			ALLOC_GROW(parents, parents_nr + 1, parents_alloc);
 			parents[parents_nr].tree = tree;
 			parents[parents_nr].size = size;
-			hashcpy(parents[parents_nr].sha1, root.hash);
+			oidcpy(&parents[parents_nr].oid, &root);
 			parents_nr++;
 
 			if (namebuf.buf[0] == '\0') {
-				hashcpy(result, root.hash);
+				oidcpy(result, &root);
 				retval = FOUND;
 				goto done;
 			}
@@ -663,7 +663,7 @@
 
 		/* We could end up here via a symlink to dir/.. */
 		if (namebuf.buf[0] == '\0') {
-			hashcpy(result, parents[parents_nr - 1].sha1);
+			oidcpy(result, &parents[parents_nr - 1].oid);
 			retval = FOUND;
 			goto done;
 		}
@@ -677,7 +677,7 @@
 
 		if (S_ISDIR(*mode)) {
 			if (!remainder) {
-				hashcpy(result, current_tree_oid.hash);
+				oidcpy(result, &current_tree_oid);
 				retval = FOUND;
 				goto done;
 			}
@@ -687,7 +687,7 @@
 				      1 + first_slash - namebuf.buf);
 		} else if (S_ISREG(*mode)) {
 			if (!remainder) {
-				hashcpy(result, current_tree_oid.hash);
+				oidcpy(result, &current_tree_oid);
 				retval = FOUND;
 			} else {
 				retval = NOT_DIR;
diff --git a/tree-walk.h b/tree-walk.h
index 4617dee..805f58f 100644
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -64,7 +64,7 @@
 		       */
 };
 
-enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_sha1, const char *name, unsigned char *result, struct strbuf *result_path, unsigned *mode);
+enum follow_symlinks_result get_tree_entry_follow_symlinks(struct object_id *tree_oid, const char *name, struct object_id *result, struct strbuf *result_path, unsigned *mode);
 
 struct traverse_info {
 	const char *traverse_path;
diff --git a/tree.c b/tree.c
index 1c68ea5..244eb5e 100644
--- a/tree.c
+++ b/tree.c
@@ -109,7 +109,7 @@
 				    oid_to_hex(entry.oid),
 				    base->buf, entry.path);
 
-			oidcpy(&oid, &commit->tree->object.oid);
+			oidcpy(&oid, get_commit_tree_oid(commit));
 		}
 		else
 			continue;
@@ -248,7 +248,7 @@
 		if (obj->type == OBJ_TREE)
 			return (struct tree *) obj;
 		else if (obj->type == OBJ_COMMIT)
-			obj = &(((struct commit *) obj)->tree->object);
+			obj = &(get_commit_tree(((struct commit *)obj))->object);
 		else if (obj->type == OBJ_TAG)
 			obj = ((struct tag *) obj)->tagged;
 		else
diff --git a/unpack-trees.c b/unpack-trees.c
index e737450..3a85a02 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1,5 +1,6 @@
 #define NO_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
+#include "argv-array.h"
 #include "repository.h"
 #include "config.h"
 #include "dir.h"
@@ -103,6 +104,8 @@
 	const char **msgs = opts->msgs;
 	const char *msg;
 
+	argv_array_init(&opts->msgs_to_free);
+
 	if (!strcmp(cmd, "checkout"))
 		msg = advice_commit_before_merge
 		      ? _("Your local changes to the following files would be overwritten by checkout:\n%%s"
@@ -119,7 +122,7 @@
 			  "Please commit your changes or stash them before you %s.")
 		      : _("Your local changes to the following files would be overwritten by %s:\n%%s");
 	msgs[ERROR_WOULD_OVERWRITE] = msgs[ERROR_NOT_UPTODATE_FILE] =
-		xstrfmt(msg, cmd, cmd);
+		argv_array_pushf(&opts->msgs_to_free, msg, cmd, cmd);
 
 	msgs[ERROR_NOT_UPTODATE_DIR] =
 		_("Updating the following directories would lose untracked files in them:\n%s");
@@ -139,7 +142,8 @@
 		      ? _("The following untracked working tree files would be removed by %s:\n%%s"
 			  "Please move or remove them before you %s.")
 		      : _("The following untracked working tree files would be removed by %s:\n%%s");
-	msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = xstrfmt(msg, cmd, cmd);
+	msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] =
+		argv_array_pushf(&opts->msgs_to_free, msg, cmd, cmd);
 
 	if (!strcmp(cmd, "checkout"))
 		msg = advice_commit_before_merge
@@ -156,7 +160,8 @@
 		      ? _("The following untracked working tree files would be overwritten by %s:\n%%s"
 			  "Please move or remove them before you %s.")
 		      : _("The following untracked working tree files would be overwritten by %s:\n%%s");
-	msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = xstrfmt(msg, cmd, cmd);
+	msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] =
+		argv_array_pushf(&opts->msgs_to_free, msg, cmd, cmd);
 
 	/*
 	 * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we
@@ -179,6 +184,12 @@
 		opts->unpack_rejects[i].strdup_strings = 1;
 }
 
+void clear_unpack_trees_porcelain(struct unpack_trees_options *opts)
+{
+	argv_array_clear(&opts->msgs_to_free);
+	memset(opts->msgs, 0, sizeof(opts->msgs));
+}
+
 static int do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
 			 unsigned int set, unsigned int clear)
 {
@@ -290,7 +301,7 @@
 		if (!state && ce->ce_flags & CE_WT_REMOVE) {
 			repo_read_gitmodules(the_repository);
 		} else if (state && (ce->ce_flags & CE_UPDATE)) {
-			submodule_free();
+			submodule_free(the_repository);
 			checkout_entry(ce, state, NULL);
 			repo_read_gitmodules(the_repository);
 		}
@@ -398,7 +409,7 @@
 
 		if (ce->ce_flags & CE_UPDATE) {
 			if (ce->ce_flags & CE_WT_REMOVE)
-				die("BUG: both update and delete flags are set on %s",
+				BUG("both update and delete flags are set on %s",
 				    ce->name);
 			display_progress(progress, ++cnt);
 			ce->ce_flags &= ~CE_UPDATE;
@@ -1284,10 +1295,21 @@
 	o->result.timestamp.sec = o->src_index->timestamp.sec;
 	o->result.timestamp.nsec = o->src_index->timestamp.nsec;
 	o->result.version = o->src_index->version;
-	o->result.split_index = o->src_index->split_index;
-	if (o->result.split_index)
+	if (!o->src_index->split_index) {
+		o->result.split_index = NULL;
+	} else if (o->src_index == o->dst_index) {
+		/*
+		 * o->dst_index (and thus o->src_index) will be discarded
+		 * and overwritten with o->result at the end of this function,
+		 * so just use src_index's split_index to avoid having to
+		 * create a new one.
+		 */
+		o->result.split_index = o->src_index->split_index;
 		o->result.split_index->refcount++;
-	hashcpy(o->result.sha1, o->src_index->sha1);
+	} else {
+		o->result.split_index = init_split_index(&o->result);
+	}
+	oidcpy(&o->result.oid, &o->src_index->oid);
 	o->merge_size = len;
 	mark_all_ce_unused(o->src_index);
 
@@ -1401,7 +1423,6 @@
 		}
 	}
 
-	o->src_index = NULL;
 	ret = check_updates(o) ? (-2) : 0;
 	if (o->dst_index) {
 		if (!ret) {
@@ -1412,12 +1433,13 @@
 						  WRITE_TREE_SILENT |
 						  WRITE_TREE_REPAIR);
 		}
-		move_index_extensions(&o->result, o->dst_index);
+		move_index_extensions(&o->result, o->src_index);
 		discard_index(o->dst_index);
 		*o->dst_index = o->result;
 	} else {
 		discard_index(&o->result);
 	}
+	o->src_index = NULL;
 
 done:
 	clear_exclude_list(&el);
@@ -1509,8 +1531,8 @@
 		add_rejected_path(o, error_type, ce->name);
 }
 
-static int verify_uptodate(const struct cache_entry *ce,
-			   struct unpack_trees_options *o)
+int verify_uptodate(const struct cache_entry *ce,
+		    struct unpack_trees_options *o)
 {
 	if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
 		return 0;
diff --git a/unpack-trees.h b/unpack-trees.h
index 6c48117b..c2b434c 100644
--- a/unpack-trees.h
+++ b/unpack-trees.h
@@ -1,7 +1,8 @@
 #ifndef UNPACK_TREES_H
 #define UNPACK_TREES_H
 
-#include "string-list.h"
+#include "tree-walk.h"
+#include "argv-array.h"
 
 #define MAX_UNPACK_TREES 8
 
@@ -32,6 +33,11 @@
 void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
 				  const char *cmd);
 
+/*
+ * Frees resources allocated by setup_unpack_trees_porcelain().
+ */
+void clear_unpack_trees_porcelain(struct unpack_trees_options *opts);
+
 struct unpack_trees_options {
 	unsigned int reset,
 		     merge,
@@ -56,6 +62,7 @@
 	struct pathspec *pathspec;
 	merge_fn_t fn;
 	const char *msgs[NB_UNPACK_TREES_ERROR_TYPES];
+	struct argv_array msgs_to_free;
 	/*
 	 * Store error messages in an array, each case
 	 * corresponding to a error message type
@@ -78,6 +85,9 @@
 extern int unpack_trees(unsigned n, struct tree_desc *t,
 		struct unpack_trees_options *options);
 
+int verify_uptodate(const struct cache_entry *ce,
+		    struct unpack_trees_options *o);
+
 int threeway_merge(const struct cache_entry * const *stages,
 		   struct unpack_trees_options *o);
 int twoway_merge(const struct cache_entry * const *src,
diff --git a/upload-pack.c b/upload-pack.c
index 6261d4f..87c6722 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -6,7 +6,6 @@
 #include "tag.h"
 #include "object.h"
 #include "commit.h"
-#include "exec-cmd.h"
 #include "diff.h"
 #include "revision.h"
 #include "list-objects.h"
@@ -17,16 +16,12 @@
 #include "sigchain.h"
 #include "version.h"
 #include "string-list.h"
-#include "parse-options.h"
 #include "argv-array.h"
 #include "prio-queue.h"
 #include "protocol.h"
 #include "quote.h"
-
-static const char * const upload_pack_usage[] = {
-	N_("git upload-pack [<options>] <dir>"),
-	NULL
-};
+#include "upload-pack.h"
+#include "serve.h"
 
 /* Remember to update object flag allocation in object.h */
 #define THEY_HAVE	(1u << 11)
@@ -64,7 +59,6 @@
  * otherwise maximum packet size (up to 65520 bytes).
  */
 static int use_sideband;
-static int advertise_refs;
 static int stateless_rpc;
 static const char *pack_objects_hook;
 
@@ -450,7 +444,7 @@
 				break;
 			default:
 				got_common = 1;
-				memcpy(last_hex, oid_to_hex(&oid), 41);
+				oid_to_hex_r(last_hex, &oid);
 				if (multi_ack == 2)
 					packet_write_fmt(1, "ACK %s common\n", last_hex);
 				else if (multi_ack)
@@ -492,7 +486,7 @@
 		"rev-list", "--stdin", NULL,
 	};
 	struct object *o;
-	char namebuf[42]; /* ^ + SHA-1 + LF */
+	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
 	int i;
 
 	cmd->argv = argv;
@@ -561,15 +555,17 @@
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	int i;
 	struct object *o;
-	char namebuf[42]; /* ^ + SHA-1 + LF */
+	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
+	const unsigned hexsz = the_hash_algo->hexsz;
 
 	if (do_reachable_revlist(&cmd, src, reachable) < 0)
 		return -1;
 
-	while ((i = read_in_full(cmd.out, namebuf, 41)) == 41) {
+	while ((i = read_in_full(cmd.out, namebuf, hexsz + 1)) == hexsz + 1) {
 		struct object_id sha1;
+		const char *p;
 
-		if (namebuf[40] != '\n' || get_oid_hex(namebuf, &sha1))
+		if (parse_oid_hex(namebuf, &sha1, &p) || *p != '\n')
 			break;
 
 		o = lookup_object(sha1.hash);
@@ -734,7 +730,6 @@
 	}
 
 	send_unshallow(shallows);
-	packet_flush(1);
 }
 
 static void deepen_by_rev_list(int ac, const char **av,
@@ -746,7 +741,122 @@
 	send_shallow(result);
 	free_commit_list(result);
 	send_unshallow(shallows);
-	packet_flush(1);
+}
+
+/* Returns 1 if a shallow list is sent or 0 otherwise */
+static int send_shallow_list(int depth, int deepen_rev_list,
+			     timestamp_t deepen_since,
+			     struct string_list *deepen_not,
+			     struct object_array *shallows)
+{
+	int ret = 0;
+
+	if (depth > 0 && deepen_rev_list)
+		die("git upload-pack: deepen and deepen-since (or deepen-not) cannot be used together");
+	if (depth > 0) {
+		deepen(depth, deepen_relative, shallows);
+		ret = 1;
+	} else if (deepen_rev_list) {
+		struct argv_array av = ARGV_ARRAY_INIT;
+		int i;
+
+		argv_array_push(&av, "rev-list");
+		if (deepen_since)
+			argv_array_pushf(&av, "--max-age=%"PRItime, deepen_since);
+		if (deepen_not->nr) {
+			argv_array_push(&av, "--not");
+			for (i = 0; i < deepen_not->nr; i++) {
+				struct string_list_item *s = deepen_not->items + i;
+				argv_array_push(&av, s->string);
+			}
+			argv_array_push(&av, "--not");
+		}
+		for (i = 0; i < want_obj.nr; i++) {
+			struct object *o = want_obj.objects[i].item;
+			argv_array_push(&av, oid_to_hex(&o->oid));
+		}
+		deepen_by_rev_list(av.argc, av.argv, shallows);
+		argv_array_clear(&av);
+		ret = 1;
+	} else {
+		if (shallows->nr > 0) {
+			int i;
+			for (i = 0; i < shallows->nr; i++)
+				register_shallow(&shallows->objects[i].item->oid);
+		}
+	}
+
+	shallow_nr += shallows->nr;
+	return ret;
+}
+
+static int process_shallow(const char *line, struct object_array *shallows)
+{
+	const char *arg;
+	if (skip_prefix(line, "shallow ", &arg)) {
+		struct object_id oid;
+		struct object *object;
+		if (get_oid_hex(arg, &oid))
+			die("invalid shallow line: %s", line);
+		object = parse_object(&oid);
+		if (!object)
+			return 1;
+		if (object->type != OBJ_COMMIT)
+			die("invalid shallow object %s", oid_to_hex(&oid));
+		if (!(object->flags & CLIENT_SHALLOW)) {
+			object->flags |= CLIENT_SHALLOW;
+			add_object_array(object, NULL, shallows);
+		}
+		return 1;
+	}
+
+	return 0;
+}
+
+static int process_deepen(const char *line, int *depth)
+{
+	const char *arg;
+	if (skip_prefix(line, "deepen ", &arg)) {
+		char *end = NULL;
+		*depth = (int)strtol(arg, &end, 0);
+		if (!end || *end || *depth <= 0)
+			die("Invalid deepen: %s", line);
+		return 1;
+	}
+
+	return 0;
+}
+
+static int process_deepen_since(const char *line, timestamp_t *deepen_since, int *deepen_rev_list)
+{
+	const char *arg;
+	if (skip_prefix(line, "deepen-since ", &arg)) {
+		char *end = NULL;
+		*deepen_since = parse_timestamp(arg, &end, 0);
+		if (!end || *end || !deepen_since ||
+		    /* revisions.c's max_age -1 is special */
+		    *deepen_since == -1)
+			die("Invalid deepen-since: %s", line);
+		*deepen_rev_list = 1;
+		return 1;
+	}
+	return 0;
+}
+
+static int process_deepen_not(const char *line, struct string_list *deepen_not, int *deepen_rev_list)
+{
+	const char *arg;
+	if (skip_prefix(line, "deepen-not ", &arg)) {
+		char *ref = NULL;
+		struct object_id oid;
+		if (expand_ref(arg, strlen(arg), &oid, &ref) != 1)
+			die("git upload-pack: ambiguous deepen-not: %s", line);
+		string_list_append(deepen_not, ref);
+		free(ref);
+		*deepen_rev_list = 1;
+		return 1;
+	}
+	return 0;
 }
 
 static void receive_needs(void)
@@ -770,61 +880,26 @@
 		if (!line)
 			break;
 
-		if (skip_prefix(line, "shallow ", &arg)) {
-			struct object_id oid;
-			struct object *object;
-			if (get_oid_hex(arg, &oid))
-				die("invalid shallow line: %s", line);
-			object = parse_object(&oid);
-			if (!object)
-				continue;
-			if (object->type != OBJ_COMMIT)
-				die("invalid shallow object %s", oid_to_hex(&oid));
-			if (!(object->flags & CLIENT_SHALLOW)) {
-				object->flags |= CLIENT_SHALLOW;
-				add_object_array(object, NULL, &shallows);
-			}
+		if (process_shallow(line, &shallows))
 			continue;
-		}
-		if (skip_prefix(line, "deepen ", &arg)) {
-			char *end = NULL;
-			depth = strtol(arg, &end, 0);
-			if (!end || *end || depth <= 0)
-				die("Invalid deepen: %s", line);
+		if (process_deepen(line, &depth))
 			continue;
-		}
-		if (skip_prefix(line, "deepen-since ", &arg)) {
-			char *end = NULL;
-			deepen_since = parse_timestamp(arg, &end, 0);
-			if (!end || *end || !deepen_since ||
-			    /* revisions.c's max_age -1 is special */
-			    deepen_since == -1)
-				die("Invalid deepen-since: %s", line);
-			deepen_rev_list = 1;
+		if (process_deepen_since(line, &deepen_since, &deepen_rev_list))
 			continue;
-		}
-		if (skip_prefix(line, "deepen-not ", &arg)) {
-			char *ref = NULL;
-			struct object_id oid;
-			if (expand_ref(arg, strlen(arg), &oid, &ref) != 1)
-				die("git upload-pack: ambiguous deepen-not: %s", line);
-			string_list_append(&deepen_not, ref);
-			free(ref);
-			deepen_rev_list = 1;
+		if (process_deepen_not(line, &deepen_not, &deepen_rev_list))
 			continue;
-		}
+
 		if (skip_prefix(line, "filter ", &arg)) {
 			if (!filter_capability_requested)
 				die("git upload-pack: filtering capability not negotiated");
 			parse_list_objects_filter(&filter_options, arg);
 			continue;
 		}
-		if (!skip_prefix(line, "want ", &arg) ||
-		    get_oid_hex(arg, &oid_buf))
-			die("git upload-pack: protocol error, "
-			    "expected to get sha, not '%s'", line);
 
-		features = arg + 40;
+		if (!skip_prefix(line, "want ", &arg) ||
+		    parse_oid_hex(arg, &oid_buf, &features))
+			die("git upload-pack: protocol error, "
+			    "expected to get object ID, not '%s'", line);
 
 		if (parse_feature_request(features, "deepen-relative"))
 			deepen_relative = 1;
@@ -881,40 +956,10 @@
 
 	if (depth == 0 && !deepen_rev_list && shallows.nr == 0)
 		return;
-	if (depth > 0 && deepen_rev_list)
-		die("git upload-pack: deepen and deepen-since (or deepen-not) cannot be used together");
-	if (depth > 0)
-		deepen(depth, deepen_relative, &shallows);
-	else if (deepen_rev_list) {
-		struct argv_array av = ARGV_ARRAY_INIT;
-		int i;
 
-		argv_array_push(&av, "rev-list");
-		if (deepen_since)
-			argv_array_pushf(&av, "--max-age=%"PRItime, deepen_since);
-		if (deepen_not.nr) {
-			argv_array_push(&av, "--not");
-			for (i = 0; i < deepen_not.nr; i++) {
-				struct string_list_item *s = deepen_not.items + i;
-				argv_array_push(&av, s->string);
-			}
-			argv_array_push(&av, "--not");
-		}
-		for (i = 0; i < want_obj.nr; i++) {
-			struct object *o = want_obj.objects[i].item;
-			argv_array_push(&av, oid_to_hex(&o->oid));
-		}
-		deepen_by_rev_list(av.argc, av.argv, &shallows);
-		argv_array_clear(&av);
-	}
-	else
-		if (shallows.nr > 0) {
-			int i;
-			for (i = 0; i < shallows.nr; i++)
-				register_shallow(&shallows.objects[i].item->oid);
-		}
-
-	shallow_nr += shallows.nr;
+	if (send_shallow_list(depth, deepen_rev_list, deepen_since,
+			      &deepen_not, &shallows))
+		packet_flush(1);
 	object_array_clear(&shallows);
 }
 
@@ -1004,33 +1049,6 @@
 	return 0;
 }
 
-static void upload_pack(void)
-{
-	struct string_list symref = STRING_LIST_INIT_DUP;
-
-	head_ref_namespaced(find_symref, &symref);
-
-	if (advertise_refs || !stateless_rpc) {
-		reset_timeout();
-		head_ref_namespaced(send_ref, &symref);
-		for_each_namespaced_ref(send_ref, &symref);
-		advertise_shallow_grafts(1);
-		packet_flush(1);
-	} else {
-		head_ref_namespaced(check_ref, NULL);
-		for_each_namespaced_ref(check_ref, NULL);
-	}
-	string_list_clear(&symref, 1);
-	if (advertise_refs)
-		return;
-
-	receive_needs();
-	if (want_obj.nr) {
-		get_common_commits();
-		create_pack_file();
-	}
-}
-
 static int upload_pack_config(const char *var, const char *value, void *unused)
 {
 	if (!strcmp("uploadpack.allowtipsha1inwant", var)) {
@@ -1061,58 +1079,371 @@
 	return parse_hide_refs_config(var, value, "uploadpack");
 }
 
-int cmd_main(int argc, const char **argv)
+void upload_pack(struct upload_pack_options *options)
 {
-	const char *dir;
-	int strict = 0;
-	struct option options[] = {
-		OPT_BOOL(0, "stateless-rpc", &stateless_rpc,
-			 N_("quit after a single request/response exchange")),
-		OPT_BOOL(0, "advertise-refs", &advertise_refs,
-			 N_("exit immediately after initial ref advertisement")),
-		OPT_BOOL(0, "strict", &strict,
-			 N_("do not try <directory>/.git/ if <directory> is no Git directory")),
-		OPT_INTEGER(0, "timeout", &timeout,
-			    N_("interrupt transfer after <n> seconds of inactivity")),
-		OPT_END()
-	};
+	struct string_list symref = STRING_LIST_INIT_DUP;
 
-	packet_trace_identity("upload-pack");
-	check_replace_refs = 0;
-
-	argc = parse_options(argc, argv, NULL, options, upload_pack_usage, 0);
-
-	if (argc != 1)
-		usage_with_options(upload_pack_usage, options);
-
-	if (timeout)
-		daemon_mode = 1;
-
-	setup_path();
-
-	dir = argv[0];
-
-	if (!enter_repo(dir, strict))
-		die("'%s' does not appear to be a git repository", dir);
+	stateless_rpc = options->stateless_rpc;
+	timeout = options->timeout;
+	daemon_mode = options->daemon_mode;
 
 	git_config(upload_pack_config, NULL);
 
-	switch (determine_protocol_version_server()) {
-	case protocol_v1:
-		/*
-		 * v1 is just the original protocol with a version string,
-		 * so just fall through after writing the version string.
-		 */
-		if (advertise_refs || !stateless_rpc)
-			packet_write_fmt(1, "version 1\n");
+	head_ref_namespaced(find_symref, &symref);
 
-		/* fallthrough */
-	case protocol_v0:
-		upload_pack();
-		break;
-	case protocol_unknown_version:
-		BUG("unknown protocol version");
+	if (options->advertise_refs || !stateless_rpc) {
+		reset_timeout();
+		head_ref_namespaced(send_ref, &symref);
+		for_each_namespaced_ref(send_ref, &symref);
+		advertise_shallow_grafts(1);
+		packet_flush(1);
+	} else {
+		head_ref_namespaced(check_ref, NULL);
+		for_each_namespaced_ref(check_ref, NULL);
+	}
+	string_list_clear(&symref, 1);
+	if (options->advertise_refs)
+		return;
+
+	receive_needs();
+	if (want_obj.nr) {
+		get_common_commits();
+		create_pack_file();
+	}
+}
+
+struct upload_pack_data {
+	struct object_array wants;
+	struct oid_array haves;
+
+	struct object_array shallows;
+	struct string_list deepen_not;
+	int depth;
+	timestamp_t deepen_since;
+	int deepen_rev_list;
+	int deepen_relative;
+
+	unsigned stateless_rpc : 1;
+
+	unsigned use_thin_pack : 1;
+	unsigned use_ofs_delta : 1;
+	unsigned no_progress : 1;
+	unsigned use_include_tag : 1;
+	unsigned done : 1;
+};
+
+static void upload_pack_data_init(struct upload_pack_data *data)
+{
+	struct object_array wants = OBJECT_ARRAY_INIT;
+	struct oid_array haves = OID_ARRAY_INIT;
+	struct object_array shallows = OBJECT_ARRAY_INIT;
+	struct string_list deepen_not = STRING_LIST_INIT_DUP;
+
+	memset(data, 0, sizeof(*data));
+	data->wants = wants;
+	data->haves = haves;
+	data->shallows = shallows;
+	data->deepen_not = deepen_not;
+}
+
+static void upload_pack_data_clear(struct upload_pack_data *data)
+{
+	object_array_clear(&data->wants);
+	oid_array_clear(&data->haves);
+	object_array_clear(&data->shallows);
+	string_list_clear(&data->deepen_not, 0);
+}
+
+static int parse_want(const char *line)
+{
+	const char *arg;
+	if (skip_prefix(line, "want ", &arg)) {
+		struct object_id oid;
+		struct object *o;
+
+		if (get_oid_hex(arg, &oid))
+			die("git upload-pack: protocol error, "
+			    "expected to get oid, not '%s'", line);
+
+		o = parse_object(&oid);
+		if (!o) {
+			packet_write_fmt(1,
+					 "ERR upload-pack: not our ref %s",
+					 oid_to_hex(&oid));
+			die("git upload-pack: not our ref %s",
+			    oid_to_hex(&oid));
+		}
+
+		if (!(o->flags & WANTED)) {
+			o->flags |= WANTED;
+			add_object_array(o, NULL, &want_obj);
+		}
+
+		return 1;
 	}
 
 	return 0;
 }
+
+static int parse_have(const char *line, struct oid_array *haves)
+{
+	const char *arg;
+	if (skip_prefix(line, "have ", &arg)) {
+		struct object_id oid;
+
+		if (get_oid_hex(arg, &oid))
+			die("git upload-pack: expected SHA1 object, got '%s'", arg);
+		oid_array_append(haves, &oid);
+		return 1;
+	}
+
+	return 0;
+}
+
+static void process_args(struct packet_reader *request,
+			 struct upload_pack_data *data)
+{
+	while (packet_reader_read(request) != PACKET_READ_FLUSH) {
+		const char *arg = request->line;
+		const char *p;
+
+		/* process want */
+		if (parse_want(arg))
+			continue;
+		/* process have line */
+		if (parse_have(arg, &data->haves))
+			continue;
+
+		/* process args like thin-pack */
+		if (!strcmp(arg, "thin-pack")) {
+			use_thin_pack = 1;
+			continue;
+		}
+		if (!strcmp(arg, "ofs-delta")) {
+			use_ofs_delta = 1;
+			continue;
+		}
+		if (!strcmp(arg, "no-progress")) {
+			no_progress = 1;
+			continue;
+		}
+		if (!strcmp(arg, "include-tag")) {
+			use_include_tag = 1;
+			continue;
+		}
+		if (!strcmp(arg, "done")) {
+			data->done = 1;
+			continue;
+		}
+
+		/* Shallow related arguments */
+		if (process_shallow(arg, &data->shallows))
+			continue;
+		if (process_deepen(arg, &data->depth))
+			continue;
+		if (process_deepen_since(arg, &data->deepen_since,
+					 &data->deepen_rev_list))
+			continue;
+		if (process_deepen_not(arg, &data->deepen_not,
+				       &data->deepen_rev_list))
+			continue;
+		if (!strcmp(arg, "deepen-relative")) {
+			data->deepen_relative = 1;
+			continue;
+		}
+
+		if (allow_filter && skip_prefix(arg, "filter ", &p)) {
+			parse_list_objects_filter(&filter_options, p);
+			continue;
+		}
+
+		/* ignore unknown lines maybe? */
+		die("unexpected line: '%s'", arg);
+	}
+}
+
+static int process_haves(struct oid_array *haves, struct oid_array *common)
+{
+	int i;
+
+	/* Process haves */
+	for (i = 0; i < haves->nr; i++) {
+		const struct object_id *oid = &haves->oid[i];
+		struct object *o;
+		int we_knew_they_have = 0;
+
+		if (!has_object_file(oid))
+			continue;
+
+		oid_array_append(common, oid);
+
+		o = parse_object(oid);
+		if (!o)
+			die("oops (%s)", oid_to_hex(oid));
+		if (o->type == OBJ_COMMIT) {
+			struct commit_list *parents;
+			struct commit *commit = (struct commit *)o;
+			if (o->flags & THEY_HAVE)
+				we_knew_they_have = 1;
+			else
+				o->flags |= THEY_HAVE;
+			if (!oldest_have || (commit->date < oldest_have))
+				oldest_have = commit->date;
+			for (parents = commit->parents;
+			     parents;
+			     parents = parents->next)
+				parents->item->object.flags |= THEY_HAVE;
+		}
+		if (!we_knew_they_have)
+			add_object_array(o, NULL, &have_obj);
+	}
+
+	return 0;
+}
+
+static int send_acks(struct oid_array *acks, struct strbuf *response)
+{
+	int i;
+
+	packet_buf_write(response, "acknowledgments\n");
+
+	/* Send Acks */
+	if (!acks->nr)
+		packet_buf_write(response, "NAK\n");
+
+	for (i = 0; i < acks->nr; i++) {
+		packet_buf_write(response, "ACK %s\n",
+				 oid_to_hex(&acks->oid[i]));
+	}
+
+	if (ok_to_give_up()) {
+		/* Send Ready */
+		packet_buf_write(response, "ready\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+static int process_haves_and_send_acks(struct upload_pack_data *data)
+{
+	struct oid_array common = OID_ARRAY_INIT;
+	struct strbuf response = STRBUF_INIT;
+	int ret = 0;
+
+	process_haves(&data->haves, &common);
+	if (data->done) {
+		ret = 1;
+	} else if (send_acks(&common, &response)) {
+		packet_buf_delim(&response);
+		ret = 1;
+	} else {
+		/* Add Flush */
+		packet_buf_flush(&response);
+		ret = 0;
+	}
+
+	/* Send response */
+	write_or_die(1, response.buf, response.len);
+	strbuf_release(&response);
+
+	oid_array_clear(&data->haves);
+	oid_array_clear(&common);
+	return ret;
+}
+
+static void send_shallow_info(struct upload_pack_data *data)
+{
+	/* No shallow info needs to be sent */
+	if (!data->depth && !data->deepen_rev_list && !data->shallows.nr &&
+	    !is_repository_shallow())
+		return;
+
+	packet_write_fmt(1, "shallow-info\n");
+
+	if (!send_shallow_list(data->depth, data->deepen_rev_list,
+			       data->deepen_since, &data->deepen_not,
+			       &data->shallows) && is_repository_shallow())
+		deepen(INFINITE_DEPTH, data->deepen_relative, &data->shallows);
+
+	packet_delim(1);
+}
+
+enum fetch_state {
+	FETCH_PROCESS_ARGS = 0,
+	FETCH_SEND_ACKS,
+	FETCH_SEND_PACK,
+	FETCH_DONE,
+};
+
+int upload_pack_v2(struct repository *r, struct argv_array *keys,
+		   struct packet_reader *request)
+{
+	enum fetch_state state = FETCH_PROCESS_ARGS;
+	struct upload_pack_data data;
+
+	git_config(upload_pack_config, NULL);
+
+	upload_pack_data_init(&data);
+	use_sideband = LARGE_PACKET_MAX;
+
+	while (state != FETCH_DONE) {
+		switch (state) {
+		case FETCH_PROCESS_ARGS:
+			process_args(request, &data);
+
+			if (!want_obj.nr) {
+				/*
+				 * Request didn't contain any 'want' lines,
+				 * guess they didn't want anything.
+				 */
+				state = FETCH_DONE;
+			} else if (data.haves.nr) {
+				/*
+				 * Request had 'have' lines, so lets ACK them.
+				 */
+				state = FETCH_SEND_ACKS;
+			} else {
+				/*
+				 * Request had 'want's but no 'have's so we can
+				 * immedietly go to construct and send a pack.
+				 */
+				state = FETCH_SEND_PACK;
+			}
+			break;
+		case FETCH_SEND_ACKS:
+			if (process_haves_and_send_acks(&data))
+				state = FETCH_SEND_PACK;
+			else
+				state = FETCH_DONE;
+			break;
+		case FETCH_SEND_PACK:
+			send_shallow_info(&data);
+
+			packet_write_fmt(1, "packfile\n");
+			create_pack_file();
+			state = FETCH_DONE;
+			break;
+		case FETCH_DONE:
+			continue;
+		}
+	}
+
+	upload_pack_data_clear(&data);
+	return 0;
+}
+
+int upload_pack_advertise(struct repository *r,
+			  struct strbuf *value)
+{
+	if (value) {
+		int allow_filter_value;
+		strbuf_addstr(value, "shallow");
+		if (!repo_config_get_bool(the_repository,
+					 "uploadpack.allowfilter",
+					 &allow_filter_value) &&
+		    allow_filter_value)
+			strbuf_addstr(value, " filter");
+	}
+	return 1;
+}
diff --git a/upload-pack.h b/upload-pack.h
new file mode 100644
index 0000000..cab2178
--- /dev/null
+++ b/upload-pack.h
@@ -0,0 +1,23 @@
+#ifndef UPLOAD_PACK_H
+#define UPLOAD_PACK_H
+
+struct upload_pack_options {
+	int stateless_rpc;
+	int advertise_refs;
+	unsigned int timeout;
+	int daemon_mode;
+};
+
+void upload_pack(struct upload_pack_options *options);
+
+struct repository;
+struct argv_array;
+struct packet_reader;
+extern int upload_pack_v2(struct repository *r, struct argv_array *keys,
+			  struct packet_reader *request);
+
+struct strbuf;
+extern int upload_pack_advertise(struct repository *r,
+				 struct strbuf *value);
+
+#endif /* UPLOAD_PACK_H */
diff --git a/usage.c b/usage.c
index cdd534c..cc80333 100644
--- a/usage.c
+++ b/usage.c
@@ -148,6 +148,7 @@
 		}
 	}
 	str_error[j] = 0;
+	/* Truncation is acceptable here */
 	snprintf(buf, n, "%s: %s", fmt, str_error);
 	return buf;
 }
@@ -210,6 +211,9 @@
 	va_end(params);
 }
 
+/* Only set this, ever, from t/helper/, when verifying that bugs are caught. */
+int BUG_exit_code;
+
 static NORETURN void BUG_vfl(const char *file, int line, const char *fmt, va_list params)
 {
 	char prefix[256];
@@ -221,6 +225,8 @@
 		snprintf(prefix, sizeof(prefix), "BUG: ");
 
 	vreportf(prefix, fmt, params);
+	if (BUG_exit_code)
+		exit(BUG_exit_code);
 	abort();
 }
 
diff --git a/utf8.c b/utf8.c
index 4419055..d55e20c 100644
--- a/utf8.c
+++ b/utf8.c
@@ -401,18 +401,40 @@
 	strbuf_release(&sb_dst);
 }
 
+/*
+ * Returns true (1) if the src encoding name matches the dst encoding
+ * name directly or one of its alternative names. E.g. UTF-16BE is the
+ * same as UTF16BE.
+ */
+static int same_utf_encoding(const char *src, const char *dst)
+{
+	if (istarts_with(src, "utf") && istarts_with(dst, "utf")) {
+		/* src[3] or dst[3] might be '\0' */
+		int i = (src[3] == '-' ? 4 : 3);
+		int j = (dst[3] == '-' ? 4 : 3);
+		return !strcasecmp(src+i, dst+j);
+	}
+	return 0;
+}
+
 int is_encoding_utf8(const char *name)
 {
 	if (!name)
 		return 1;
-	if (!strcasecmp(name, "utf-8") || !strcasecmp(name, "utf8"))
+	if (same_utf_encoding("utf-8", name))
 		return 1;
 	return 0;
 }
 
 int same_encoding(const char *src, const char *dst)
 {
-	if (is_encoding_utf8(src) && is_encoding_utf8(dst))
+	static const char utf8[] = "UTF-8";
+
+	if (!src)
+		src = utf8;
+	if (!dst)
+		dst = utf8;
+	if (same_utf_encoding(src, dst))
 		return 1;
 	return !strcasecmp(src, dst);
 }
@@ -538,6 +560,45 @@
 }
 #endif
 
+static int has_bom_prefix(const char *data, size_t len,
+			  const char *bom, size_t bom_len)
+{
+	return data && bom && (len >= bom_len) && !memcmp(data, bom, bom_len);
+}
+
+static const char utf16_be_bom[] = {0xFE, 0xFF};
+static const char utf16_le_bom[] = {0xFF, 0xFE};
+static const char utf32_be_bom[] = {0x00, 0x00, 0xFE, 0xFF};
+static const char utf32_le_bom[] = {0xFF, 0xFE, 0x00, 0x00};
+
+int has_prohibited_utf_bom(const char *enc, const char *data, size_t len)
+{
+	return (
+	  (same_utf_encoding("UTF-16BE", enc) ||
+	   same_utf_encoding("UTF-16LE", enc)) &&
+	  (has_bom_prefix(data, len, utf16_be_bom, sizeof(utf16_be_bom)) ||
+	   has_bom_prefix(data, len, utf16_le_bom, sizeof(utf16_le_bom)))
+	) || (
+	  (same_utf_encoding("UTF-32BE",  enc) ||
+	   same_utf_encoding("UTF-32LE", enc)) &&
+	  (has_bom_prefix(data, len, utf32_be_bom, sizeof(utf32_be_bom)) ||
+	   has_bom_prefix(data, len, utf32_le_bom, sizeof(utf32_le_bom)))
+	);
+}
+
+int is_missing_required_utf_bom(const char *enc, const char *data, size_t len)
+{
+	return (
+	   (same_utf_encoding(enc, "UTF-16")) &&
+	   !(has_bom_prefix(data, len, utf16_be_bom, sizeof(utf16_be_bom)) ||
+	     has_bom_prefix(data, len, utf16_le_bom, sizeof(utf16_le_bom)))
+	) || (
+	   (same_utf_encoding(enc, "UTF-32")) &&
+	   !(has_bom_prefix(data, len, utf32_be_bom, sizeof(utf32_be_bom)) ||
+	     has_bom_prefix(data, len, utf32_le_bom, sizeof(utf32_le_bom)))
+	);
+}
+
 /*
  * Returns first character length in bytes for multi-byte `text` according to
  * `encoding`.
@@ -620,28 +681,33 @@
 	}
 }
 
-int is_hfs_dotgit(const char *path)
+static int is_hfs_dot_generic(const char *path,
+			      const char *needle, size_t needle_len)
 {
 	ucs_char_t c;
 
 	c = next_hfs_char(&path);
 	if (c != '.')
 		return 0;
-	c = next_hfs_char(&path);
 
 	/*
 	 * there's a great deal of other case-folding that occurs
-	 * in HFS+, but this is enough to catch anything that will
-	 * convert to ".git"
+	 * in HFS+, but this is enough to catch our fairly vanilla
+	 * hard-coded needles.
 	 */
-	if (c != 'g' && c != 'G')
-		return 0;
-	c = next_hfs_char(&path);
-	if (c != 'i' && c != 'I')
-		return 0;
-	c = next_hfs_char(&path);
-	if (c != 't' && c != 'T')
-		return 0;
+	for (; needle_len > 0; needle++, needle_len--) {
+		c = next_hfs_char(&path);
+
+		/*
+		 * We know our needles contain only ASCII, so we clamp here to
+		 * make the results of tolower() sane.
+		 */
+		if (c > 127)
+			return 0;
+		if (tolower(c) != *needle)
+			return 0;
+	}
+
 	c = next_hfs_char(&path);
 	if (c && !is_dir_sep(c))
 		return 0;
@@ -649,6 +715,35 @@
 	return 1;
 }
 
+/*
+ * Inline wrapper to make sure the compiler resolves strlen() on literals at
+ * compile time.
+ */
+static inline int is_hfs_dot_str(const char *path, const char *needle)
+{
+	return is_hfs_dot_generic(path, needle, strlen(needle));
+}
+
+int is_hfs_dotgit(const char *path)
+{
+	return is_hfs_dot_str(path, "git");
+}
+
+int is_hfs_dotgitmodules(const char *path)
+{
+	return is_hfs_dot_str(path, "gitmodules");
+}
+
+int is_hfs_dotgitignore(const char *path)
+{
+	return is_hfs_dot_str(path, "gitignore");
+}
+
+int is_hfs_dotgitattributes(const char *path)
+{
+	return is_hfs_dot_str(path, "gitattributes");
+}
+
 const char utf8_bom[] = "\357\273\277";
 
 int skip_utf8_bom(char **text, size_t len)
diff --git a/utf8.h b/utf8.h
index 6bbcf31..db73a2d 100644
--- a/utf8.h
+++ b/utf8.h
@@ -52,8 +52,13 @@
  * The path should be NUL-terminated, but we will match variants of both ".git\0"
  * and ".git/..." (but _not_ ".../.git"). This makes it suitable for both fsck
  * and verify_path().
+ *
+ * Likewise, the is_hfs_dotgitfoo() variants look for ".gitfoo".
  */
 int is_hfs_dotgit(const char *path);
+int is_hfs_dotgitmodules(const char *path);
+int is_hfs_dotgitignore(const char *path);
+int is_hfs_dotgitattributes(const char *path);
 
 typedef enum {
 	ALIGN_LEFT,
@@ -70,4 +75,32 @@
 void strbuf_utf8_align(struct strbuf *buf, align_type position, unsigned int width,
 		       const char *s);
 
+/*
+ * If a data stream is declared as UTF-16BE or UTF-16LE, then a UTF-16
+ * BOM must not be used [1]. The same applies for the UTF-32 equivalents.
+ * The function returns true if this rule is violated.
+ *
+ * [1] http://unicode.org/faq/utf_bom.html#bom10
+ */
+int has_prohibited_utf_bom(const char *enc, const char *data, size_t len);
+
+/*
+ * If the endianness is not defined in the encoding name, then we
+ * require a BOM. The function returns true if a required BOM is missing.
+ *
+ * The Unicode standard instructs to assume big-endian if there in no
+ * BOM for UTF-16/32 [1][2]. However, the W3C/WHATWG encoding standard
+ * used in HTML5 recommends to assume little-endian to "deal with
+ * deployed content" [3].
+ *
+ * Therefore, strictly requiring a BOM seems to be the safest option for
+ * content in Git.
+ *
+ * [1] http://unicode.org/faq/utf_bom.html#gen6
+ * [2] http://www.unicode.org/versions/Unicode10.0.0/ch03.pdf
+ *     Section 3.10, D98, page 132
+ * [3] https://encoding.spec.whatwg.org/#utf-16le
+ */
+int is_missing_required_utf_bom(const char *enc, const char *data, size_t len);
+
 #endif
diff --git a/vcs-svn/fast_export.c b/vcs-svn/fast_export.c
index 3fd047a..b5b8913 100644
--- a/vcs-svn/fast_export.c
+++ b/vcs-svn/fast_export.c
@@ -320,7 +320,8 @@
 	err = fast_export_ls(path, mode_out, &buf);
 	if (err) {
 		if (errno != ENOENT)
-			die_errno("BUG: unexpected fast_export_ls error");
+			BUG("unexpected fast_export_ls error: %s",
+			    strerror(errno));
 		/* Treat missing paths as directories. */
 		*mode_out = S_IFDIR;
 		return NULL;
@@ -338,7 +339,8 @@
 	err = fast_export_ls_rev(revision, src, &mode, &data);
 	if (err) {
 		if (errno != ENOENT)
-			die_errno("BUG: unexpected fast_export_ls_rev error");
+			BUG("unexpected fast_export_ls_rev error: %s",
+			    strerror(errno));
 		fast_export_delete(dst);
 		return;
 	}
diff --git a/walker.c b/walker.c
index dffb9c8..0b162a0 100644
--- a/walker.c
+++ b/walker.c
@@ -72,6 +72,8 @@
 
 static int process_commit(struct walker *walker, struct commit *commit)
 {
+	struct commit_list *parents;
+
 	if (parse_commit(commit))
 		return -1;
 
@@ -86,19 +88,14 @@
 
 	walker_say(walker, "walk %s\n", oid_to_hex(&commit->object.oid));
 
-	if (walker->get_tree) {
-		if (process(walker, &commit->tree->object))
+	if (process(walker, &get_commit_tree(commit)->object))
+		return -1;
+
+	for (parents = commit->parents; parents; parents = parents->next) {
+		if (process(walker, &parents->item->object))
 			return -1;
-		if (!walker->get_all)
-			walker->get_tree = 0;
 	}
-	if (walker->get_history) {
-		struct commit_list *parents = commit->parents;
-		for (; parents; parents = parents->next) {
-			if (process(walker, &parents->item->object))
-				return -1;
-		}
-	}
+
 	return 0;
 }
 
diff --git a/walker.h b/walker.h
index a869013..6d8ae00 100644
--- a/walker.h
+++ b/walker.h
@@ -9,9 +9,6 @@
 	void (*prefetch)(struct walker *, unsigned char *sha1);
 	int (*fetch)(struct walker *, unsigned char *sha1);
 	void (*cleanup)(struct walker *);
-	int get_tree;
-	int get_history;
-	int get_all;
 	int get_verbosely;
 	int get_recover;
 
diff --git a/worktree.c b/worktree.c
index 28989cf..97cda5f 100644
--- a/worktree.c
+++ b/worktree.c
@@ -338,7 +338,7 @@
 	struct strbuf path = STRBUF_INIT;
 
 	if (is_main_worktree(wt))
-		die("BUG: can't relocate main worktree");
+		BUG("can't relocate main worktree");
 
 	strbuf_realpath(&path, path_, 1);
 	if (fspathcmp(wt->path, path.buf)) {
diff --git a/wrap-for-bin.sh b/wrap-for-bin.sh
index 5842408..95851b8 100644
--- a/wrap-for-bin.sh
+++ b/wrap-for-bin.sh
@@ -20,10 +20,17 @@
 
 export GIT_EXEC_PATH GITPERLLIB PATH GIT_TEXTDOMAINDIR
 
-if test -n "$GIT_TEST_GDB"
-then
-	unset GIT_TEST_GDB
-	exec gdb --args "${GIT_EXEC_PATH}/@@PROG@@" "$@"
-else
+case "$GIT_DEBUGGER" in
+'')
 	exec "${GIT_EXEC_PATH}/@@PROG@@" "$@"
-fi
+	;;
+1)
+	unset GIT_DEBUGGER
+	exec gdb --args "${GIT_EXEC_PATH}/@@PROG@@" "$@"
+	;;
+*)
+	GIT_DEBUGGER_ARGS="$GIT_DEBUGGER"
+	unset GIT_DEBUGGER
+	exec ${GIT_DEBUGGER_ARGS} "${GIT_EXEC_PATH}/@@PROG@@" "$@"
+	;;
+esac
diff --git a/wrapper.c b/wrapper.c
index 1fd5e33..e4fa9d8 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -643,9 +643,9 @@
 	va_end(ap);
 
 	if (len < 0)
-		die("BUG: your snprintf is broken");
+		BUG("your snprintf is broken");
 	if (len >= max)
-		die("BUG: attempt to snprintf into too-small buffer");
+		BUG("attempt to snprintf into too-small buffer");
 	return len;
 }
 
diff --git a/wt-status.c b/wt-status.c
index 50815e5..d1c0514 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -138,6 +138,9 @@
 	s->show_stash = 0;
 	s->ahead_behind_flags = AHEAD_BEHIND_UNSPECIFIED;
 	s->display_comment_prefix = 0;
+	s->detect_rename = -1;
+	s->rename_score = -1;
+	s->rename_limit = -1;
 }
 
 static void wt_longstatus_print_unmerged_header(struct wt_status *s)
@@ -264,7 +267,7 @@
 	case 7:
 		return _("both modified:");
 	default:
-		die("BUG: unhandled unmerged status %x", stagemask);
+		BUG("unhandled unmerged status %x", stagemask);
 	}
 }
 
@@ -377,7 +380,7 @@
 		status = d->worktree_status;
 		break;
 	default:
-		die("BUG: unhandled change_type %d in wt_longstatus_print_change_data",
+		BUG("unhandled change_type %d in wt_longstatus_print_change_data",
 		    change_type);
 	}
 
@@ -395,7 +398,7 @@
 	status_printf(s, color(WT_STATUS_HEADER, s), "\t");
 	what = wt_status_diff_status_string(status);
 	if (!what)
-		die("BUG: unhandled diff status %c", status);
+		BUG("unhandled diff status %c", status);
 	len = label_width - utf8_strwidth(what);
 	assert(len >= 0);
 	if (one_name != two_name)
@@ -470,7 +473,7 @@
 		case DIFF_STATUS_COPIED:
 		case DIFF_STATUS_RENAMED:
 			if (d->rename_status)
-				die("BUG: multiple renames on the same target? how?");
+				BUG("multiple renames on the same target? how?");
 			d->rename_source = xstrdup(p->one->path);
 			d->rename_score = p->score * 100 / MAX_SCORE;
 			d->rename_status = p->status;
@@ -484,7 +487,7 @@
 			break;
 
 		default:
-			die("BUG: unhandled diff-files status '%c'", p->status);
+			BUG("unhandled diff-files status '%c'", p->status);
 			break;
 		}
 
@@ -547,7 +550,7 @@
 		case DIFF_STATUS_COPIED:
 		case DIFF_STATUS_RENAMED:
 			if (d->rename_status)
-				die("BUG: multiple renames on the same target? how?");
+				BUG("multiple renames on the same target? how?");
 			d->rename_source = xstrdup(p->one->path);
 			d->rename_score = p->score * 100 / MAX_SCORE;
 			d->rename_status = p->status;
@@ -569,7 +572,7 @@
 			break;
 
 		default:
-			die("BUG: unhandled diff-index status '%c'", p->status);
+			BUG("unhandled diff-index status '%c'", p->status);
 			break;
 		}
 	}
@@ -592,6 +595,9 @@
 	}
 	rev.diffopt.format_callback = wt_status_collect_changed_cb;
 	rev.diffopt.format_callback_data = s;
+	rev.diffopt.detect_rename = s->detect_rename >= 0 ? s->detect_rename : rev.diffopt.detect_rename;
+	rev.diffopt.rename_limit = s->rename_limit >= 0 ? s->rename_limit : rev.diffopt.rename_limit;
+	rev.diffopt.rename_score = s->rename_score >= 0 ? s->rename_score : rev.diffopt.rename_score;
 	copy_pathspec(&rev.prune_data, &s->pathspec);
 	run_diff_files(&rev, 0);
 }
@@ -603,7 +609,7 @@
 
 	init_revisions(&rev, NULL);
 	memset(&opt, 0, sizeof(opt));
-	opt.def = s->is_initial ? EMPTY_TREE_SHA1_HEX : s->reference;
+	opt.def = s->is_initial ? empty_tree_oid_hex() : s->reference;
 	setup_revisions(0, NULL, &rev, &opt);
 
 	rev.diffopt.flags.override_submodule_config = 1;
@@ -625,9 +631,9 @@
 	rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
 	rev.diffopt.format_callback = wt_status_collect_updated_cb;
 	rev.diffopt.format_callback_data = s;
-	rev.diffopt.detect_rename = DIFF_DETECT_RENAME;
-	rev.diffopt.rename_limit = 200;
-	rev.diffopt.break_opt = 0;
+	rev.diffopt.detect_rename = s->detect_rename >= 0 ? s->detect_rename : rev.diffopt.detect_rename;
+	rev.diffopt.rename_limit = s->rename_limit >= 0 ? s->rename_limit : rev.diffopt.rename_limit;
+	rev.diffopt.rename_score = s->rename_score >= 0 ? s->rename_score : rev.diffopt.rename_score;
 	copy_pathspec(&rev.prune_data, &s->pathspec);
 	run_diff_index(&rev, 1);
 }
@@ -981,11 +987,13 @@
 	rev.diffopt.ita_invisible_in_index = 1;
 
 	memset(&opt, 0, sizeof(opt));
-	opt.def = s->is_initial ? EMPTY_TREE_SHA1_HEX : s->reference;
+	opt.def = s->is_initial ? empty_tree_oid_hex() : s->reference;
 	setup_revisions(0, NULL, &rev, &opt);
 
 	rev.diffopt.output_format |= DIFF_FORMAT_PATCH;
-	rev.diffopt.detect_rename = DIFF_DETECT_RENAME;
+	rev.diffopt.detect_rename = s->detect_rename >= 0 ? s->detect_rename : rev.diffopt.detect_rename;
+	rev.diffopt.rename_limit = s->rename_limit >= 0 ? s->rename_limit : rev.diffopt.rename_limit;
+	rev.diffopt.rename_score = s->rename_score >= 0 ? s->rename_score : rev.diffopt.rename_score;
 	rev.diffopt.file = s->fp;
 	rev.diffopt.close_file = 0;
 	/*
@@ -2158,7 +2166,7 @@
 	case 6: key = "AA"; break; /* both added */
 	case 7: key = "UU"; break; /* both modified */
 	default:
-		die("BUG: unhandled unmerged status %x", d->stagemask);
+		BUG("unhandled unmerged status %x", d->stagemask);
 	}
 
 	/*
@@ -2185,7 +2193,7 @@
 		sum |= (1 << (stage - 1));
 	}
 	if (sum != d->stagemask)
-		die("BUG: observed stagemask 0x%x != expected stagemask 0x%x", sum, d->stagemask);
+		BUG("observed stagemask 0x%x != expected stagemask 0x%x", sum, d->stagemask);
 
 	if (s->null_termination)
 		path_index = it->string;
@@ -2289,7 +2297,7 @@
 		wt_porcelain_v2_print(s);
 		break;
 	case STATUS_FORMAT_UNSPECIFIED:
-		die("BUG: finalize_deferred_config() should have been called");
+		BUG("finalize_deferred_config() should have been called");
 		break;
 	case STATUS_FORMAT_NONE:
 	case STATUS_FORMAT_LONG:
diff --git a/wt-status.h b/wt-status.h
index 430770b..1673d14 100644
--- a/wt-status.h
+++ b/wt-status.h
@@ -89,7 +89,9 @@
 	int show_stash;
 	int hints;
 	enum ahead_behind_flags ahead_behind_flags;
-
+	int detect_rename;
+	int rename_score;
+	int rename_limit;
 	enum wt_status_format status_format;
 	unsigned char sha1_commit[GIT_MAX_RAWSZ]; /* when not Initial */
 
diff --git a/zlib.c b/zlib.c
index 4223f1a..d594cba 100644
--- a/zlib.c
+++ b/zlib.c
@@ -52,9 +52,9 @@
 	bytes_consumed = s->z.next_in - s->next_in;
 	bytes_produced = s->z.next_out - s->next_out;
 	if (s->z.total_out != s->total_out + bytes_produced)
-		die("BUG: total_out mismatch");
+		BUG("total_out mismatch");
 	if (s->z.total_in != s->total_in + bytes_consumed)
-		die("BUG: total_in mismatch");
+		BUG("total_in mismatch");
 
 	s->total_out = s->z.total_out;
 	s->total_in = s->z.total_in;