Merge branch 'jh/verify-index-checksum-only-in-fsck'

* jh/verify-index-checksum-only-in-fsck:
  t1450: avoid use of "sed" on the index, which is a binary file
diff --git a/.travis.yml b/.travis.yml
index 591cc57..1b32c98 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -39,6 +39,17 @@
 
 matrix:
   include:
+    - env: Windows
+      os: linux
+      compiler:
+      addons:
+      before_install:
+      before_script:
+      script:
+        - >
+          test "$TRAVIS_REPO_SLUG" != "git/git" ||
+          ci/run-windows-build.sh $TRAVIS_BRANCH $(git rev-parse HEAD)
+      after_failure:
     - env: Linux32
       os: linux
       services:
@@ -50,6 +61,7 @@
         - >
           docker run
           --interactive
+          --env DEVELOPER
           --env DEFAULT_TEST_TARGET
           --env GIT_PROVE_OPTS
           --env GIT_TEST_OPTS
@@ -60,6 +72,18 @@
         # Use the following command to debug the docker build locally:
         # $ docker run -itv "${PWD}:/usr/src/git" --entrypoint /bin/bash daald/ubuntu32:xenial
         # root@container:/# /usr/src/git/ci/run-linux32-build.sh
+    - env: Static Analysis
+      os: linux
+      compiler:
+      addons:
+        apt:
+          packages:
+          - coccinelle
+      before_install:
+      script:
+        # "before_script" that builds Git is inherited from base job
+        - make coccicheck
+      after_failure:
     - env: Documentation
       os: linux
       compiler: clang
diff --git a/Documentation/RelNotes/2.13.0.txt b/Documentation/RelNotes/2.13.0.txt
index 993e493..80dca93 100644
--- a/Documentation/RelNotes/2.13.0.txt
+++ b/Documentation/RelNotes/2.13.0.txt
@@ -12,13 +12,19 @@
    release (yet).
 
  * The historical argument order "git merge <msg> HEAD <commit>..."
-   has been deprecated for quite some time, and will be removed in a
-   future release.
+   has been deprecated for quite some time, and is now removed.
 
  * The default location "~/.git-credential-cache/socket" for the
    socket used to communicate with the credential-cache daemon has
    been moved to "~/.cache/git/credential/socket".
 
+ * Git now avoids blindly falling back to ".git" when the setup
+   sequence said we are _not_ in Git repository.  A corner case that
+   happens to work right now may be broken by a call to die("BUG").
+   We've tried hard to locate such cases and fixed them, but there
+   might still be cases that need to be addressed--bug reports are
+   greatly appreciated.
+
 
 Updates since v2.12
 -------------------
@@ -145,6 +151,56 @@
    doing other things, output from reset seeped out).  These, and
    other chattyness has been fixed.
 
+ * "git merge <message> HEAD <commit>" syntax that has been deprecated
+   since October 2007 has been removed.
+
+ * The refs completion for large number of refs has been sped up,
+   partly by giving up disambiguating ambiguous refs and partly by
+   eliminating most of the shell processing between 'git for-each-ref'
+   and 'ls-remote' and Bash's completion facility.
+
+ * On many keyboards, typing "@{" involves holding down SHIFT key and
+   one can easily end up with "@{Up..." when typing "@{upstream}".  As
+   the upstream/push keywords do not appear anywhere else in the syntax,
+   we can safely accept them case insensitively without introducing
+   ambiguity or confusion to solve this.
+
+ * "git tag/branch/for-each-ref" family of commands long allowed to
+   filter the refs by "--contains X" (show only the refs that are
+   descendants of X), "--merged X" (show only the refs that are
+   ancestors of X), "--no-merged X" (show only the refs that are not
+   ancestors of X).  One curious omission, "--no-contains X" (show
+   only the refs that are not descendants of X) has been added to
+   them.
+
+ * The default behaviour of "git log" in an interactive session has
+   been changed to enable "--decorate".
+
+ * The output from "git status --short" has been extended to show
+   various kinds of dirtyness in submodules differently; instead of to
+   "M" for modified, 'm' and '?' can be shown to signal changes only
+   to the working tree of the submodule but not the commit that is
+   checked out.
+
+ * Allow the http.postbuffer configuration variable to be set to a
+   size that can be expressed in size_t, which can be larger than
+   ulong on some platforms.
+
+ * "git rebase" learns "--signoff" option.
+
+ * The completion script (in contrib/) learned to complete "git push
+   --delete b<TAB>" to complete branch name to be deleted.
+
+ * "git worktree add --lock" allows to lock a worktree immediately
+   after it's created. This helps prevent a race between "git worktree
+   add; git worktree lock" and "git worktree prune".
+
+ * Completion for "git checkout <branch>" that auto-creates the branch
+   out of a remote tracking branch can now be disabled, as this
+   completion often gets in the way when completing to checkout an
+   existing local branch that happens to share the same prefix with
+   bunch of remote tracking branches.
+
 
 Performance, Internal Implementation, Development Support etc.
 
@@ -205,8 +261,6 @@
    older one and the newer one interoperate happily has now become
    possible.
 
- * "uchar [40]" to "struct object_id" conversion continues.
-
  * "git tag --contains" used to (ab)use the object bits to keep track
    of the state of object reachability without clearing them after
    use; this has been cleaned up and made to use the newer commit-slab
@@ -228,6 +282,56 @@
  * An earlier version of sha1dc/sha1.c that was merged to 'master'
    compiled incorrectly on Windows, which has been fixed.
 
+ * "what URL do we want to update this submodule?" and "are we
+   interested in this submodule?" are split into two distinct
+   concepts, and then the way used to express the latter got extended,
+   paving a way to make it easier to manage a project with many
+   submodules and make it possible to later extend use of multiple
+   worktrees for a project with submodules.
+
+ * Some debugging output from "git describe" were marked for l10n,
+   but some weren't.  Mark missing ones for l10n.
+
+ * Define a new task in .travis.yml that triggers a test session on
+   Windows run elsewhere.
+
+ * Conversion from uchar[20] to struct object_id continues.
+
+ * The "submodule" specific field in the ref_store structure is
+   replaced with a more generic "gitdir" that can later be used also
+   when dealing with ref_store that represents the set of refs visible
+   from the other worktrees.
+
+ * The string-list API used a custom reallocation strategy that was
+   very inefficient, instead of using the usual ALLOC_GROW() macro,
+   which has been fixed.
+   (merge 950a234cbd jh/string-list-micro-optim later to maint).
+
+ * In a 2- and 3-way merge of trees, more than one source trees often
+   end up sharing an identical subtree; optimize by not reading the
+   same tree multiple times in such a case.
+   (merge d12a8cf0af jh/unpack-trees-micro-optim later to maint).
+
+ * The index file has a trailing SHA-1 checksum to detect file
+   corruption, and historically we checked it every time the index
+   file is used.  Omit the validation during normal use, and instead
+   verify only in "git fsck".
+
+ * Having a git command on the upstream side of a pipe in a test
+   script will hide the exit status from the command, which may cause
+   us to fail to notice a breakage; rewrite tests in a script to avoid
+   this issue.
+
+ * Travis CI learns to run coccicheck.
+
+ * "git checkout" that handles a lot of paths has been optimized by
+   reducing the number of unnecessary checks of paths in the
+   has_dir_name() function.
+
+ * The internals of the refs API around the cached refs has been
+   streamlined.
+
+ * Output from perf tests have been updated to align their titles.
 
 Also contains various documentation updates and code clean-ups.
 
@@ -377,8 +481,131 @@
  * Fix for NO_PTHREADS option.
    (merge 2225e1ea20 bw/grep-recurse-submodules later to maint).
 
+ * Git now avoids blindly falling back to ".git" when the setup
+   sequence said we are _not_ in Git repository.  A corner case that
+   happens to work right now may be broken by a call to die("BUG").
+   (merge b1ef400eec jk/no-looking-at-dotgit-outside-repo-final later to maint).
+
+ * A few commands that recently learned the "--recurse-submodule"
+   option misbehaved when started from a subdirectory of the
+   superproject.
+   (merge b2dfeb7c00 bw/recurse-submodules-relative-fix later to maint).
+
+ * FreeBSD implementation of getcwd(3) behaved differently when an
+   intermediate directory is unreadable/unsearchable depending on the
+   length of the buffer provided, which our strbuf_getcwd() was not
+   aware of.  strbuf_getcwd() has been taught to cope with it better.
+   (merge a54e938e5b rs/freebsd-getcwd-workaround later to maint).
+
+ * A recent update to "rebase -i" stopped running hooks for the "git
+   commit" command during "reword" action, which has been fixed.
+
+ * Removing an entry from a notes tree and then looking another note
+   entry from the resulting tree using the internal notes API
+   functions did not work as expected.  No in-tree users of the API
+   has such access pattern, but it still is worth fixing.
+
+ * "git receive-pack" could have been forced to die by attempting
+   allocate an unreasonably large amount of memory with a crafted push
+   certificate; this has been fixed.
+   (merge f2214dede9 bc/push-cert-receive-fix later to maint).
+
+ * Update error handling for codepath that deals with corrupt loose
+   objects.
+   (merge 51054177b3 jk/loose-object-info-report-error later to maint).
+
+ * "git diff --submodule=diff" learned to work better in a project
+   with a submodule that in turn has its own submodules.
+   (merge 17b254cda6 sb/show-diff-for-submodule-in-diff-fix later to maint).
+
+ * Update the build dependency so that an update to /usr/bin/perl
+   etc. result in recomputation of perl.mak file.
+   (merge c59c4939c2 ab/regen-perl-mak-with-different-perl later to maint).
+
+ * "git push --recurse-submodules --push-option=<string>" learned to
+   propagate the push option recursively down to pushes in submodules.
+
+ * If a patch e-mail had its first paragraph after an in-body header
+   indented (even after a blank line after the in-body header line),
+   the indented line was mistook as a continuation of the in-body
+   header.  This has been fixed.
+   (merge fd1062e52e lt/mailinfo-in-body-header-continuation later to maint).
+
+ * Clean up fallouts from recent tightening of the set-up sequence,
+   where Git barfs when repository information is accessed without
+   first ensuring that it was started in a repository.
+   (merge bccb22cbb1 jk/no-looking-at-dotgit-outside-repo later to maint).
+
+ * "git p4" used "name-rev HEAD" when it wants to learn what branch is
+   checked out; it should use "symbolic-ref HEAD".
+   (merge eff451101d ld/p4-current-branch-fix later to maint).
+
+ * "http.proxy" set to an empty string is used to disable the usage of
+   proxy.  We broke this early last year.
+   (merge ae51d91105 sr/http-proxy-configuration-fix later to maint).
+
+ * $GIT_DIR may in some cases be normalized with all symlinks resolved
+   while "gitdir" path expansion in the pattern does not receive the
+   same treatment, leading to incorrect mismatch.  This has been fixed.
+
+ * "git submodule" script does not work well with strange pathnames.
+   Protect it from a path with slashes in them, at least.
+
+ * "git fetch-pack" was not prepared to accept ERR packet that the
+   upload-pack can send with a human-readable error message.  It
+   showed the packet contents with ERR prefix, so there was no data
+   loss, but it was redundant to say "ERR" in an error message.
+   (merge 8e2c7bef03 jt/fetch-pack-error-reporting later to maint).
+
+ * "ls-files --recurse-submodules" did not quite work well in a
+   project with nested submodules.
+
+ * gethostname(2) may not NUL terminate the buffer if hostname does
+   not fit; unfortunately there is no easy way to see if our buffer
+   was too small, but at least this will make sure we will not end up
+   using garbage past the end of the buffer.
+   (merge 5781a9a270 dt/xgethostname-nul-termination later to maint).
+
+ * A recent update broke "git add -p ../foo" from a subdirectory.
+
+ * While handy, "git_path()" is a dangerous function to use as a
+   callsite that uses it safely one day can be broken by changes
+   to other code that calls it.  Reduction of its use continues.
+   (merge 16d2676c9e jk/war-on-git-path later to maint).
+
+ * The split-index code configuration code used an unsafe git_path()
+   function without copying its result out.
+
+ * Many stale HTTP(s) links have been updated in our documentation.
+   (merge 613416f0be jk/update-links-in-docs later to maint).
+
  * Other minor doc, test and build updates and code cleanups.
    (merge df2a6e38b7 jk/pager-in-use later to maint).
    (merge 75ec4a6cb0 ab/branch-list-doc later to maint).
    (merge 3e5b36c637 sg/skip-prefix-in-prettify-refname later to maint).
    (merge 2c5e2865cc jk/fast-import-cleanup later to maint).
+   (merge 4473060bc2 ab/test-readme-updates later to maint).
+   (merge 48a96972fd ab/doc-submitting later to maint).
+   (merge f5c2bc2b96 jk/make-coccicheck-detect-errors later to maint).
+   (merge c105f563d1 cc/untracked later to maint).
+   (merge 8668976b53 jc/unused-symbols later to maint).
+   (merge fba275dc93 jc/bs-t-is-not-a-tab-for-sed later to maint).
+   (merge be6ed145de mm/ls-files-s-doc later to maint).
+   (merge 60b091c679 qp/bisect-docfix later to maint).
+   (merge 47242cd103 ah/diff-files-ours-theirs-doc later to maint).
+   (merge 35ad44cbd8 sb/submodule-rm-absorb later to maint).
+   (merge 0301f1fd92 va/i18n-perl-scripts later to maint).
+   (merge 733e064d98 vn/revision-shorthand-for-side-branch-log later to maint).
+   (merge 85999743e7 tb/doc-eol-normalization later to maint).
+   (merge 0747fb49fd jk/loose-object-fsck later to maint).
+   (merge d8f4481c4f jk/quarantine-received-objects later to maint).
+   (merge 7ba1ceef95 xy/format-patch-base later to maint).
+   (merge fa1912c89a rs/misc-cppcheck-fixes later to maint).
+   (merge f17d642d3b ab/push-cas-doc-n-test later to maint).
+   (merge 61e282425a ss/gitmodules-ignore-doc later to maint).
+   (merge 8d3047cd5b ss/submodule-shallow-doc later to maint).
+   (merge 1f9e18b772 jk/prio-queue-avoid-swap-with-self later to maint).
+   (merge 627fde1025 jk/submodule-init-segv-fix later to maint).
+   (merge d395745d81 rg/doc-pull-typofix later to maint).
+   (merge 01e60a9a22 rg/doc-submittingpatches-wordfix later to maint).
+   (merge 501d3cd7b8 sr/hooks-cwd-doc later to maint).
diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches
index 3faf7eb..558d465 100644
--- a/Documentation/SubmittingPatches
+++ b/Documentation/SubmittingPatches
@@ -51,7 +51,7 @@
 probably need to split up your commit to finer grained pieces.
 That being said, patches which plainly describe the things that
 help reviewers check the patch, and future maintainers understand
-the code, are the most beautiful patches.  Descriptions that summarise
+the code, are the most beautiful patches.  Descriptions that summarize
 the point in the subject well, and describe the motivation for the
 change, the approach taken by the change, and if relevant how this
 differs substantially from the prior version, are all good things
@@ -87,7 +87,7 @@
 Oh, another thing.  We are picky about whitespaces.  Make sure your
 changes do not trigger errors with the sample pre-commit hook shipped
 in templates/hooks--pre-commit.  To help ensure this does not happen,
-run git diff --check on your changes before you commit.
+run "git diff --check" on your changes before you commit.
 
 
 (2) Describe your changes well.
@@ -98,18 +98,23 @@
 prefix the first line with "area: " where the area is a filename or
 identifier for the general area of the code being modified, e.g.
 
-  . archive: ustar header checksum is computed unsigned
-  . git-cherry-pick.txt: clarify the use of revision range notation
+  . doc: clarify distinction between sign-off and pgp-signing
+  . githooks.txt: improve the intro section
 
 If in doubt which identifier to use, run "git log --no-merges" on the
 files you are modifying to see the current conventions.
 
+It's customary to start the remainder of the first line after "area: "
+with a lower-case letter. E.g. "doc: clarify...", not "doc:
+Clarify...", or "githooks.txt: improve...", not "githooks.txt:
+Improve...".
+
 The body should provide a meaningful commit message, which:
 
-  . explains the problem the change tries to solve, iow, what is wrong
+  . explains the problem the change tries to solve, i.e. what is wrong
     with the current code without the change.
 
-  . justifies the way the change solves the problem, iow, why the
+  . justifies the way the change solves the problem, i.e. why the
     result with the change is better.
 
   . alternate solutions considered but discarded, if any.
@@ -117,7 +122,7 @@
 Describe your changes in imperative mood, e.g. "make xyzzy do frotz"
 instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy
 to do frotz", as if you are giving orders to the codebase to change
-its behaviour.  Try to make sure your explanation can be understood
+its behavior.  Try to make sure your explanation can be understood
 without external resources. Instead of giving a URL to a mailing list
 archive, summarize the relevant points of the discussion.
 
@@ -129,8 +134,9 @@
     noticed that ...
 
 The "Copy commit summary" command of gitk can be used to obtain this
-format.
+format, or this invocation of "git show":
 
+    git show -s --date=short --pretty='format:%h ("%s", %ad)' <commit>
 
 (3) Generate your patch using Git tools out of your commits.
 
@@ -255,7 +261,7 @@
 The sign-off is a simple line at the end of the explanation for
 the patch, which certifies that you wrote it or otherwise have
 the right to pass it on as a open-source patch.  The rules are
-pretty simple: if you can certify the below:
+pretty simple: if you can certify the below D-C-O:
 
         Developer's Certificate of Origin 1.1
 
diff --git a/Documentation/config.txt b/Documentation/config.txt
index 1df1965..475e874 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -3013,8 +3013,9 @@
 	The URL for a submodule. This variable is copied from the .gitmodules
 	file to the git config via 'git submodule init'. The user can change
 	the configured URL before obtaining the submodule via 'git submodule
-	update'. After obtaining the submodule, the presence of this variable
-	is used as a sign whether the submodule is of interest to git commands.
+	update'. If neither submodule.<name>.active or submodule.active are
+	set, the presence of this variable is used as a fallback to indicate
+	whether the submodule is of interest to git commands.
 	See linkgit:git-submodule[1] and linkgit:gitmodules[5] for details.
 
 submodule.<name>.update::
@@ -3052,6 +3053,16 @@
 	"--ignore-submodules" option. The 'git submodule' commands are not
 	affected by this setting.
 
+submodule.<name>.active::
+	Boolean value indicating if the submodule is of interest to git
+	commands.  This config option takes precedence over the
+	submodule.active config option.
+
+submodule.active::
+	A repeated field which contains a pathspec used to match against a
+	submodule's path to determine if the submodule is of interest to git
+	commands.
+
 submodule.fetchJobs::
 	Specifies how many submodules are fetched/cloned at the same time.
 	A positive integer allows up to that number of submodules fetched
diff --git a/Documentation/git-archimport.txt b/Documentation/git-archimport.txt
index 163b9f6..ea70653 100644
--- a/Documentation/git-archimport.txt
+++ b/Documentation/git-archimport.txt
@@ -96,7 +96,7 @@
 	pruned.
 
 -a::
-	Attempt to auto-register archives at http://mirrors.sourcecontrol.net
+	Attempt to auto-register archives at `http://mirrors.sourcecontrol.net`
 	This is particularly useful with the -D option.
 
 -t <tmpdir>::
diff --git a/Documentation/git-bisect-lk2009.txt b/Documentation/git-bisect-lk2009.txt
index e015f5b..8ac75fc 100644
--- a/Documentation/git-bisect-lk2009.txt
+++ b/Documentation/git-bisect-lk2009.txt
@@ -1347,12 +1347,12 @@
 References
 ----------
 
-- [[[1]]] http://www.nist.gov/public_affairs/releases/n02-10.htm['Software Errors Cost U.S. Economy $59.5 Billion Annually'. Nist News Release.]
-- [[[2]]] http://java.sun.com/docs/codeconv/html/CodeConventions.doc.html#16712['Code Conventions for the Java Programming Language'. Sun Microsystems.]
-- [[[3]]] http://en.wikipedia.org/wiki/Software_maintenance['Software maintenance'. Wikipedia.]
+- [[[1]]] https://www.nist.gov/sites/default/files/documents/director/planning/report02-3.pdf['The Economic Impacts of Inadequate Infratructure for Software Testing'.  Nist Planning Report 02-3], see Executive Summary and Chapter 8.
+- [[[2]]] http://www.oracle.com/technetwork/java/codeconvtoc-136057.html['Code Conventions for the Java Programming Language'. Sun Microsystems.]
+- [[[3]]] https://en.wikipedia.org/wiki/Software_maintenance['Software maintenance'. Wikipedia.]
 - [[[4]]] http://article.gmane.org/gmane.comp.version-control.git/45195/[Junio C Hamano. 'Automated bisect success story'. Gmane.]
-- [[[5]]] http://lwn.net/Articles/317154/[Christian Couder. 'Fully automated bisecting with "git bisect run"'. LWN.net.]
-- [[[6]]] http://lwn.net/Articles/277872/[Jonathan Corbet. 'Bisection divides users and developers'. LWN.net.]
+- [[[5]]] https://lwn.net/Articles/317154/[Christian Couder. 'Fully automated bisecting with "git bisect run"'. LWN.net.]
+- [[[6]]] https://lwn.net/Articles/277872/[Jonathan Corbet. 'Bisection divides users and developers'. LWN.net.]
 - [[[7]]] http://article.gmane.org/gmane.linux.scsi/36652/[Ingo Molnar. 'Re: BUG 2.6.23-rc3 can't see sd partitions on Alpha'. Gmane.]
-- [[[8]]] http://www.kernel.org/pub/software/scm/git/docs/git-bisect.html[Junio C Hamano and the git-list. 'git-bisect(1) Manual Page'. Linux Kernel Archives.]
-- [[[9]]] http://github.com/Ealdwulf/bbchop[Ealdwulf. 'bbchop'. GitHub.]
+- [[[8]]] https://www.kernel.org/pub/software/scm/git/docs/git-bisect.html[Junio C Hamano and the git-list. 'git-bisect(1) Manual Page'. Linux Kernel Archives.]
+- [[[9]]] https://github.com/Ealdwulf/bbchop[Ealdwulf. 'bbchop'. GitHub.]
diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt
index bdd915a..6c42abf 100644
--- a/Documentation/git-bisect.txt
+++ b/Documentation/git-bisect.txt
@@ -137,7 +137,7 @@
 mix "good" and "bad" with "old" and "new" in a single session.)
 
 In this more general usage, you provide `git bisect` with a "new"
-commit has some property and an "old" commit that doesn't have that
+commit that has some property and an "old" commit that doesn't have that
 property. Each time `git bisect` checks out a commit, you test if that
 commit has the property. If it does, mark the commit as "new";
 otherwise, mark it as "old". When the bisection is done, `git bisect`
diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index c203e8c..81bd0a7 100644
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -10,8 +10,9 @@
 [verse]
 'git branch' [--color[=<when>] | --no-color] [-r | -a]
 	[--list] [-v [--abbrev=<length> | --no-abbrev]]
-	[--column[=<options>] | --no-column]
-	[(--merged | --no-merged | --contains) [<commit>]] [--sort=<key>]
+	[--column[=<options>] | --no-column] [--sort=<key>]
+	[(--merged | --no-merged) [<commit>]]
+	[--contains [<commit]] [--no-contains [<commit>]]
 	[--points-at <object>] [--format=<format>] [<pattern>...]
 'git branch' [--set-upstream | --track | --no-track] [-l] [-f] <branchname> [<start-point>]
 'git branch' (--set-upstream-to=<upstream> | -u <upstream>) [<branchname>]
@@ -35,11 +36,12 @@
 
 With `--contains`, shows only the branches that contain the named commit
 (in other words, the branches whose tip commits are descendants of the
-named commit).  With `--merged`, only branches merged into the named
-commit (i.e. the branches whose tip commits are reachable from the named
-commit) will be listed.  With `--no-merged` only branches not merged into
-the named commit will be listed.  If the <commit> argument is missing it
-defaults to `HEAD` (i.e. the tip of the current branch).
+named commit), `--no-contains` inverts it. With `--merged`, only branches
+merged into the named commit (i.e. the branches whose tip commits are
+reachable from the named commit) will be listed.  With `--no-merged` only
+branches not merged into the named commit will be listed.  If the <commit>
+argument is missing it defaults to `HEAD` (i.e. the tip of the current
+branch).
 
 The command's second form creates a new branch head named <branchname>
 which points to the current `HEAD`, or <start-point> if given.
@@ -218,13 +220,19 @@
 	Only list branches which contain the specified commit (HEAD
 	if not specified). Implies `--list`.
 
+--no-contains [<commit>]::
+	Only list branches which don't contain the specified commit
+	(HEAD if not specified). Implies `--list`.
+
 --merged [<commit>]::
 	Only list branches whose tips are reachable from the
-	specified commit (HEAD if not specified). Implies `--list`.
+	specified commit (HEAD if not specified). Implies `--list`,
+	incompatible with `--no-merged`.
 
 --no-merged [<commit>]::
 	Only list branches whose tips are not reachable from the
-	specified commit (HEAD if not specified). Implies `--list`.
+	specified commit (HEAD if not specified). Implies `--list`,
+	incompatible with `--merged`.
 
 <branchname>::
 	The name of the branch to create or delete.
@@ -301,13 +309,16 @@
 easier to use the git checkout command with its `-b` option to create
 a branch and check it out with a single command.
 
-The options `--contains`, `--merged` and `--no-merged` serve three related
-but different purposes:
+The options `--contains`, `--no-contains`, `--merged` and `--no-merged`
+serve four related but different purposes:
 
 - `--contains <commit>` is used to find all branches which will need
   special attention if <commit> were to be rebased or amended, since those
   branches contain the specified <commit>.
 
+- `--no-contains <commit>` is the inverse of that, i.e. branches that don't
+  contain the specified <commit>.
+
 - `--merged` is used to find all branches which can be safely deleted,
   since those branches are fully contained by HEAD.
 
diff --git a/Documentation/git-clone.txt b/Documentation/git-clone.txt
index 35cc34b..30052cc 100644
--- a/Documentation/git-clone.txt
+++ b/Documentation/git-clone.txt
@@ -14,7 +14,7 @@
 	  [-o <name>] [-b <name>] [-u <upload-pack>] [--reference <repository>]
 	  [--dissociate] [--separate-git-dir <git dir>]
 	  [--depth <depth>] [--[no-]single-branch]
-	  [--recursive | --recurse-submodules] [--[no-]shallow-submodules]
+	  [--recurse-submodules] [--[no-]shallow-submodules]
 	  [--jobs <n>] [--] <repository> [<directory>]
 
 DESCRIPTION
@@ -215,10 +215,14 @@
 	branch when `--single-branch` clone was made, no remote-tracking
 	branch is created.
 
---recursive::
---recurse-submodules::
-	After the clone is created, initialize all submodules within,
-	using their default settings. This is equivalent to running
+--recurse-submodules[=<pathspec]::
+	After the clone is created, initialize and clone submodules
+	within based on the provided pathspec.  If no pathspec is
+	provided, all submodules are initialized and cloned.
+	Submodules are initialized and cloned using their default
+	settings.  The resulting clone has `submodule.active` set to
+	the provided pathspec, or "." (meaning all submodules) if no
+	pathspec is provided.  This is equivalent to running
 	`git submodule update --init --recursive` immediately after
 	the clone is finished. This option is ignored if the cloned
 	repository does not have a worktree/checkout (i.e. if any of
diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt
index ed0f5b9..afb06ad 100644
--- a/Documentation/git-commit.txt
+++ b/Documentation/git-commit.txt
@@ -95,7 +95,7 @@
 
 --reset-author::
 	When used with -C/-c/--amend options, or when committing after a
-	a conflicting cherry-pick, declare that the authorship of the
+	conflicting cherry-pick, declare that the authorship of the
 	resulting commit now belongs to the committer. This also renews
 	the author timestamp.
 
@@ -112,7 +112,7 @@
 	`--dry-run`.
 
 --long::
-	When doing a dry-run, give the output in a the long-format.
+	When doing a dry-run, give the output in the long-format.
 	Implies `--dry-run`.
 
 -z::
diff --git a/Documentation/git-diff.txt b/Documentation/git-diff.txt
index bbab35f..b0c1bb9 100644
--- a/Documentation/git-diff.txt
+++ b/Documentation/git-diff.txt
@@ -97,6 +97,20 @@
 :git-diff: 1
 include::diff-options.txt[]
 
+-1 --base::
+-2 --ours::
+-3 --theirs::
+	Compare the working tree with the "base" version (stage #1),
+	"our branch" (stage #2) or "their branch" (stage #3).  The
+	index contains these stages only for unmerged entries i.e.
+	while resolving conflicts.  See linkgit:git-read-tree[1]
+	section "3-Way Merge" for detailed information.
+
+-0::
+	Omit diff output for unmerged entries and just show
+	"Unmerged".  Can be used only when comparing the working tree
+	with the index.
+
 <path>...::
 	The <paths> parameters, when given, are used to limit
 	the diff to the named paths (you can give directory
diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index 111e1be..03e187a 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -11,7 +11,7 @@
 'git for-each-ref' [--count=<count>] [--shell|--perl|--python|--tcl]
 		   [(--sort=<key>)...] [--format=<format>] [<pattern>...]
 		   [--points-at <object>] [(--merged | --no-merged) [<object>]]
-		   [--contains [<object>]]
+		   [--contains [<object>]] [--no-contains [<object>]]
 
 DESCRIPTION
 -----------
@@ -69,16 +69,22 @@
 
 --merged [<object>]::
 	Only list refs whose tips are reachable from the
-	specified commit (HEAD if not specified).
+	specified commit (HEAD if not specified),
+	incompatible with `--no-merged`.
 
 --no-merged [<object>]::
 	Only list refs whose tips are not reachable from the
-	specified commit (HEAD if not specified).
+	specified commit (HEAD if not specified),
+	incompatible with `--merged`.
 
 --contains [<object>]::
 	Only list refs which contain the specified commit (HEAD if not
 	specified).
 
+--no-contains [<object>]::
+	Only list refs which don't contain the specified commit (HEAD
+	if not specified).
+
 --ignore-case::
 	Sorting and filtering refs are case insensitive.
 
diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index f7a069b..c890328 100644
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -557,7 +557,7 @@
 ................................................
 
 With `git format-patch --base=P -3 C` (or variants thereof, e.g. with
-`--cover-letter` of using `Z..C` instead of `-3 C` to specify the
+`--cover-letter` or using `Z..C` instead of `-3 C` to specify the
 range), the base tree information block is shown at the end of the
 first message the command outputs (either the first patch, or the
 cover letter), like this:
diff --git a/Documentation/git-ls-files.txt b/Documentation/git-ls-files.txt
index 1cab703..d153c17 100644
--- a/Documentation/git-ls-files.txt
+++ b/Documentation/git-ls-files.txt
@@ -57,7 +57,7 @@
 
 -s::
 --stage::
-	Show staged contents' object name, mode bits and stage number in the output.
+	Show staged contents' mode bits, object name and stage number in the output.
 
 --directory::
 	If a whole directory is classified as "other", show just its
diff --git a/Documentation/git-merge.txt b/Documentation/git-merge.txt
index ca3c27b..04fdd8c 100644
--- a/Documentation/git-merge.txt
+++ b/Documentation/git-merge.txt
@@ -13,7 +13,6 @@
 	[-s <strategy>] [-X <strategy-option>] [-S[<keyid>]]
 	[--[no-]allow-unrelated-histories]
 	[--[no-]rerere-autoupdate] [-m <msg>] [<commit>...]
-'git merge' <msg> HEAD <commit>...
 'git merge' --abort
 'git merge' --continue
 
@@ -46,11 +45,7 @@
     D---E---F---G---H master
 ------------
 
-The second syntax (<msg> `HEAD` <commit>...) is supported for
-historical reasons.  Do not use it from the command line or in
-new scripts.  It is the same as `git merge -m <msg> <commit>...`.
-
-The third syntax ("`git merge --abort`") can only be run after the
+The second syntax ("`git merge --abort`") can only be run after the
 merge has resulted in conflicts. 'git merge --abort' will abort the
 merge process and try to reconstruct the pre-merge state. However,
 if there were uncommitted changes when the merge started (and
diff --git a/Documentation/git-pull.txt b/Documentation/git-pull.txt
index 4470e4b..942af8e 100644
--- a/Documentation/git-pull.txt
+++ b/Documentation/git-pull.txt
@@ -67,7 +67,7 @@
 in a state that may be hard to back out of in the case of a conflict.
 
 If any of the remote changes overlap with local uncommitted changes,
-the merge will be automatically cancelled and the work tree untouched.
+the merge will be automatically canceled and the work tree untouched.
 It is generally best to get any local changes in working order before
 pulling or stash them away with linkgit:git-stash[1].
 
@@ -210,7 +210,8 @@
   current branch:
 +
 ------------------------------------------------
-$ git pull, git pull origin
+$ git pull
+$ git pull origin
 ------------------------------------------------
 +
 Normally the branch merged in is the HEAD of the remote repository,
diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt
index 1624a35..0a63966 100644
--- a/Documentation/git-push.txt
+++ b/Documentation/git-push.txt
@@ -217,6 +217,47 @@
 +
 "--no-force-with-lease" will cancel all the previous --force-with-lease on the
 command line.
++
+A general note on safety: supplying this option without an expected
+value, i.e. as `--force-with-lease` or `--force-with-lease=<refname>`
+interacts very badly with anything that implicitly runs `git fetch` on
+the remote to be pushed to in the background, e.g. `git fetch origin`
+on your repository in a cronjob.
++
+The protection it offers over `--force` is ensuring that subsequent
+changes your work wasn't based on aren't clobbered, but this is
+trivially defeated if some background process is updating refs in the
+background. We don't have anything except the remote tracking info to
+go by as a heuristic for refs you're expected to have seen & are
+willing to clobber.
++
+If your editor or some other system is running `git fetch` in the
+background for you a way to mitigate this is to simply set up another
+remote:
++
+	git remote add origin-push $(git config remote.origin.url)
+	git fetch origin-push
++
+Now when the background process runs `git fetch origin` the references
+on `origin-push` won't be updated, and thus commands like:
++
+	git push --force-with-lease origin-push
++
+Will fail unless you manually run `git fetch origin-push`. This method
+is of course entirely defeated by something that runs `git fetch
+--all`, in that case you'd need to either disable it or do something
+more tedious like:
++
+	git fetch              # update 'master' from remote
+	git tag base master    # mark our base point
+	git rebase -i master   # rewrite some commits
+	git push --force-with-lease=master:base master:master
++
+I.e. create a `base` tag for versions of the upstream code that you've
+seen and are willing to overwrite, then rewrite history, and finally
+force push changes to `master` if the remote version is still at
+`base`, regardless of what your local `remotes/origin/master` has been
+updated to in the background.
 
 -f::
 --force::
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 67d48e6..53f4e14 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -370,6 +370,11 @@
 	of the rebased commits (see linkgit:git-am[1]).
 	Incompatible with the --interactive option.
 
+--signoff::
+	This flag is passed to 'git am' to sign off all the rebased
+	commits (see linkgit:git-am[1]). Incompatible with the
+	--interactive option.
+
 -i::
 --interactive::
 	Make a list of the commits which are about to be rebased.  Let the
diff --git a/Documentation/git-receive-pack.txt b/Documentation/git-receive-pack.txt
index 0ccd5fb..86a4b32 100644
--- a/Documentation/git-receive-pack.txt
+++ b/Documentation/git-receive-pack.txt
@@ -114,6 +114,8 @@
 hooks will not be invoked either.  This can be useful to quickly
 bail out if the update is not to be supported.
 
+See the notes on the quarantine environment below.
+
 update Hook
 -----------
 Before each ref is updated, if $GIT_DIR/hooks/update file exists
@@ -214,6 +216,33 @@
 	exec git update-server-info
 
 
+Quarantine Environment
+----------------------
+
+When `receive-pack` takes in objects, they are placed into a temporary
+"quarantine" directory within the `$GIT_DIR/objects` directory and
+migrated into the main object store only after the `pre-receive` hook
+has completed. If the push fails before then, the temporary directory is
+removed entirely.
+
+This has a few user-visible effects and caveats:
+
+  1. Pushes which fail due to problems with the incoming pack, missing
+     objects, or due to the `pre-receive` hook will not leave any
+     on-disk data. This is usually helpful to prevent repeated failed
+     pushes from filling up your disk, but can make debugging more
+     challenging.
+
+  2. Any objects created by the `pre-receive` hook will be created in
+     the quarantine directory (and migrated only if it succeeds).
+
+  3. The `pre-receive` hook MUST NOT update any refs to point to
+     quarantined objects. Other programs accessing the repository will
+     not be able to see the objects (and if the pre-receive hook fails,
+     those refs would become corrupted). For safety, any ref updates
+     from within `pre-receive` are automatically rejected.
+
+
 SEE ALSO
 --------
 linkgit:git-send-pack[1], linkgit:gitnamespaces[7]
diff --git a/Documentation/git-status.txt b/Documentation/git-status.txt
index ba87365..d70abc6 100644
--- a/Documentation/git-status.txt
+++ b/Documentation/git-status.txt
@@ -181,6 +181,17 @@
     !           !    ignored
     -------------------------------------------------
 
+Submodules have more state and instead report
+		M    the submodule has a different HEAD than
+		     recorded in the index
+		m    the submodule has modified content
+		?    the submodule has untracked files
+since modified content or untracked files in a submodule cannot be added
+via `git add` in the superproject to prepare a commit.
+
+'m' and '?' are applied recursively. For example if a nested submodule
+in a submodule contains an untracked file, this is reported as '?' as well.
+
 If -b is used the short-format status is preceded by a line
 
     ## branchname tracking info
@@ -210,6 +221,8 @@
 characters are not specially formatted; no quoting or
 backslash-escaping is performed.
 
+Any submodule changes are reported as modified `M` instead of `m` or single `?`.
+
 Porcelain Format Version 2
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index e05d0cd..74bc620 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -129,7 +129,9 @@
 	repository will be assumed to be upstream.
 +
 Optional <path> arguments limit which submodules will be initialized.
-If no path is specified, all submodules are initialized.
+If no path is specified and submodule.active has been configured, submodules
+configured to be active will be initialized, otherwise all submodules are
+initialized.
 +
 When present, it will also copy the value of `submodule.$name.update`.
 This command does not alter existing information in .git/config.
diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index 525737a..f8a0b78 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt
@@ -12,9 +12,10 @@
 'git tag' [-a | -s | -u <keyid>] [-f] [-m <msg> | -F <file>]
 	<tagname> [<commit> | <object>]
 'git tag' -d <tagname>...
-'git tag' [-n[<num>]] -l [--contains <commit>] [--points-at <object>]
-	[--column[=<options>] | --no-column] [--create-reflog] [--sort=<key>]
-	[--format=<format>] [--[no-]merged [<commit>]] [<pattern>...]
+'git tag' [-n[<num>]] -l [--contains <commit>] [--contains <commit>]
+	[--points-at <object>] [--column[=<options>] | --no-column]
+	[--create-reflog] [--sort=<key>] [--format=<format>]
+	[--[no-]merged [<commit>]] [<pattern>...]
 'git tag' -v [--format=<format>] <tagname>...
 
 DESCRIPTION
@@ -82,18 +83,24 @@
 
 -n<num>::
 	<num> specifies how many lines from the annotation, if any,
-	are printed when using -l.
-	The default is not to print any annotation lines.
-	If no number is given to `-n`, only the first line is printed.
-	If the tag is not annotated, the commit message is displayed instead.
+	are printed when using -l. Implies `--list`.
++
+The default is not to print any annotation lines.
+If no number is given to `-n`, only the first line is printed.
+If the tag is not annotated, the commit message is displayed instead.
 
--l <pattern>::
---list <pattern>::
-	List tags with names that match the given pattern (or all if no
-	pattern is given).  Running "git tag" without arguments also
-	lists all tags. The pattern is a shell wildcard (i.e., matched
-	using fnmatch(3)).  Multiple patterns may be given; if any of
-	them matches, the tag is shown.
+-l::
+--list::
+	List tags. With optional `<pattern>...`, e.g. `git tag --list
+	'v-*'`, list only the tags that match the pattern(s).
++
+Running "git tag" without arguments also lists all tags. The pattern
+is a shell wildcard (i.e., matched using fnmatch(3)). Multiple
+patterns may be given; if any of them matches, the tag is shown.
++
+This option is implicitly supplied if any other list-like option such
+as `--contains` is provided. See the documentation for each of those
+options for details.
 
 --sort=<key>::
 	Sort based on the key given.  Prefix `-` to sort in
@@ -122,10 +129,23 @@
 
 --contains [<commit>]::
 	Only list tags which contain the specified commit (HEAD if not
-	specified).
+	specified). Implies `--list`.
+
+--no-contains [<commit>]::
+	Only list tags which don't contain the specified commit (HEAD if
+	not specified). Implies `--list`.
+
+--merged [<commit>]::
+	Only list tags whose commits are reachable from the specified
+	commit (`HEAD` if not specified), incompatible with `--no-merged`.
+
+--no-merged [<commit>]::
+	Only list tags whose commits are not reachable from the specified
+	commit (`HEAD` if not specified), incompatible with `--merged`.
 
 --points-at <object>::
-	Only list tags of the given object.
+	Only list tags of the given object (HEAD if not
+	specified). Implies `--list`.
 
 -m <msg>::
 --message=<msg>::
@@ -173,11 +193,6 @@
 	that of linkgit:git-for-each-ref[1].  When unspecified,
 	defaults to `%(refname:strip=2)`.
 
---[no-]merged [<commit>]::
-	Only list tags whose tips are reachable, or not reachable
-	if `--no-merged` is used, from the specified commit (`HEAD`
-	if not specified).
-
 CONFIGURATION
 -------------
 By default, 'git tag' in sign-with-default mode (-s) will use your
diff --git a/Documentation/git-tools.txt b/Documentation/git-tools.txt
index 2f4ff50..d0fec4c 100644
--- a/Documentation/git-tools.txt
+++ b/Documentation/git-tools.txt
@@ -7,4 +7,4 @@
 more efficiently, so this manually-maintained list has been retired.
 
 See also the `contrib/` area, and the Git wiki:
-http://git.or.cz/gitwiki/InterfacesFrontendsAndTools
+https://git.wiki.kernel.org/index.php/InterfacesFrontendsAndTools
diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
index 553cf84..b472acc 100644
--- a/Documentation/git-worktree.txt
+++ b/Documentation/git-worktree.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git worktree add' [-f] [--detach] [--checkout] [-b <new-branch>] <path> [<branch>]
+'git worktree add' [-f] [--detach] [--checkout] [--lock] [-b <new-branch>] <path> [<branch>]
 'git worktree list' [--porcelain]
 'git worktree lock' [--reason <string>] <worktree>
 'git worktree prune' [-n] [-v] [--expire <expire>]
@@ -107,6 +107,11 @@
 	such as configuring sparse-checkout. See "Sparse checkout"
 	in linkgit:git-read-tree[1].
 
+--lock::
+	Keep the working tree locked after creation. This is the
+	equivalent of `git worktree lock` after `git worktree add`,
+	but without race condition.
+
 -n::
 --dry-run::
 	With `prune`, do not remove anything; just report what it would
diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index a53d093..4736483 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -229,11 +229,9 @@
 
 -------------------------------------------------
 $ echo "* text=auto" >.gitattributes
-$ rm .git/index     # Remove the index to force Git to
-$ git reset         # re-scan the working directory
+$ rm .git/index     # Remove the index to re-scan the working directory
+$ git add .
 $ git status        # Show files that will be normalized
-$ git add -u
-$ git add .gitattributes
 $ git commit -m "Introduce end-of-line normalization"
 -------------------------------------------------
 
diff --git a/Documentation/gitcore-tutorial.txt b/Documentation/gitcore-tutorial.txt
index 3a0ec8c..7577f27 100644
--- a/Documentation/gitcore-tutorial.txt
+++ b/Documentation/gitcore-tutorial.txt
@@ -1429,7 +1429,7 @@
 convenient to organize your project with an informal hierarchy
 of developers. Linux kernel development is run this way. There
 is a nice illustration (page 17, "Merges to Mainline") in
-http://www.xenotime.net/linux/mentor/linux-mentoring-2006.pdf[Randy Dunlap's presentation].
+https://web.archive.org/web/20120915203609/http://www.xenotime.net/linux/mentor/linux-mentoring-2006.pdf[Randy Dunlap's presentation].
 
 It should be stressed that this hierarchy is purely *informal*.
 There is nothing fundamental in Git that enforces the "chain of
diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt
index 9565dc3..706091a 100644
--- a/Documentation/githooks.txt
+++ b/Documentation/githooks.txt
@@ -22,8 +22,10 @@
 linkgit:git-config[1]).
 
 Before Git invokes a hook, it changes its working directory to either
-the root of the working tree in a non-bare repository, or to the
-$GIT_DIR in a bare repository.
+$GIT_DIR in a bare repository or the root of the working tree in a non-bare
+repository. An exception are hooks triggered during a push ('pre-receive',
+'update', 'post-receive', 'post-update', 'push-to-checkout') which are always
+executed in $GIT_DIR.
 
 Hooks can get their arguments via the environment, command-line
 arguments, and stdin. See the documentation for each hook below for
@@ -256,6 +258,9 @@
 to use push options, but doesn't transmit any, the count variable
 will be set to zero, `GIT_PUSH_OPTION_COUNT=0`.
 
+See the section on "Quarantine Environment" in
+linkgit:git-receive-pack[1] for some caveats.
+
 [[update]]
 update
 ~~~~~~
diff --git a/Documentation/gitmodules.txt b/Documentation/gitmodules.txt
index 8f7c50f..db5d47e 100644
--- a/Documentation/gitmodules.txt
+++ b/Documentation/gitmodules.txt
@@ -66,17 +66,26 @@
 
 submodule.<name>.ignore::
 	Defines under what circumstances "git status" and the diff family show
-	a submodule as modified. When set to "all", it will never be considered
-	modified (but will nonetheless show up in the output of status and
-	commit when it has been staged), "dirty" will ignore all changes
-	to the submodules work tree and
-	takes only differences between the HEAD of the submodule and the commit
-	recorded in the superproject into account. "untracked" will additionally
-	let submodules with modified tracked files in their work tree show up.
-	Using "none" (the default when this option is not set) also shows
-	submodules that have untracked files in their work tree as changed.
-	If this option is also present in the submodules entry in .git/config of
-	the superproject, the setting there will override the one found in
+	a submodule as modified. The following values are supported:
+
+	all;; The submodule will never be considered modified (but will
+	    nonetheless show up in the output of status and commit when it has
+	    been staged).
+
+	dirty;; All changes to the submodule's work tree will be ignored, only
+	    committed differences between the HEAD of the submodule and its
+	    recorded state in the superproject are taken into account.
+
+	untracked;; Only untracked files in submodules will be ignored.
+	    Committed differences and modifications to tracked files will show
+	    up.
+
+	none;; No modifiations to submodules are ignored, all of committed
+	    differences, and modifications to tracked and untracked files are
+	    shown. This is the default option.
+
+	If this option is also present in the submodules entry in .git/config
+	of the superproject, the setting there will override the one found in
 	.gitmodules.
 	Both settings can be overridden on the command line by using the
 	"--ignore-submodule" option. The 'git submodule' commands are not
@@ -84,8 +93,8 @@
 
 submodule.<name>.shallow::
 	When set to true, a clone of this submodule will be performed as a
-	shallow clone unless the user explicitly asks for a non-shallow
-	clone.
+	shallow clone (with a history depth of 1) unless the user explicitly
+	asks for a non-shallow clone.
 
 
 EXAMPLES
diff --git a/Documentation/gitremote-helpers.txt b/Documentation/gitremote-helpers.txt
index e4b785e..4a584f3 100644
--- a/Documentation/gitremote-helpers.txt
+++ b/Documentation/gitremote-helpers.txt
@@ -463,7 +463,7 @@
 	GPG sign pushes.
 
 'option push-option <string>::
-	Transmit <string> as a push option. As the a push option
+	Transmit <string> as a push option. As the push option
 	must not contain LF or NUL characters, the string is not encoded.
 
 SEE ALSO
diff --git a/Documentation/gitweb.conf.txt b/Documentation/gitweb.conf.txt
index e632089..9c8982e 100644
--- a/Documentation/gitweb.conf.txt
+++ b/Documentation/gitweb.conf.txt
@@ -368,8 +368,8 @@
 $logo_label::
 	URI and label (title) for the Git logo link (or your site logo,
 	if you chose to use different logo image). By default, these both
-	refer to Git homepage, http://git-scm.com[]; in the past, they pointed
-	to Git documentation at http://www.kernel.org[].
+	refer to Git homepage, https://git-scm.com[]; in the past, they pointed
+	to Git documentation at https://www.kernel.org[].
 
 
 Changing gitweb's look
diff --git a/Documentation/howto/rebuild-from-update-hook.txt b/Documentation/howto/rebuild-from-update-hook.txt
index 25378f6..db219f5 100644
--- a/Documentation/howto/rebuild-from-update-hook.txt
+++ b/Documentation/howto/rebuild-from-update-hook.txt
@@ -4,13 +4,13 @@
 Date: Fri, 26 Aug 2005 18:19:10 -0700
 Abstract: In this how-to article, JC talks about how he
  uses the post-update hook to automate Git documentation page
- shown at http://www.kernel.org/pub/software/scm/git/docs/.
+ shown at https://www.kernel.org/pub/software/scm/git/docs/.
 Content-type: text/asciidoc
 
 How to rebuild from update hook
 ===============================
 
-The pages under http://www.kernel.org/pub/software/scm/git/docs/
+The pages under https://www.kernel.org/pub/software/scm/git/docs/
 are built from Documentation/ directory of the git.git project
 and needed to be kept up-to-date.  The www.kernel.org/ servers
 are mirrored and I was told that the origin of the mirror is on
diff --git a/Documentation/revisions.txt b/Documentation/revisions.txt
index ba11b9c..6127746 100644
--- a/Documentation/revisions.txt
+++ b/Documentation/revisions.txt
@@ -96,7 +96,8 @@
   refers to the branch that the branch specified by branchname is set to build on
   top of (configured with `branch.<name>.remote` and
   `branch.<name>.merge`).  A missing branchname defaults to the
-  current one.
+  current one. These suffixes are also accepted when spelled in uppercase, and
+  they mean the same thing no matter the case.
 
 '<branchname>@\{push\}', e.g. 'master@\{push\}', '@\{push\}'::
   The suffix '@\{push}' reports the branch "where we would push to" if
@@ -122,6 +123,9 @@
 Note in the example that we set up a triangular workflow, where we pull
 from one location and push to another. In a non-triangular workflow,
 '@\{push}' is the same as '@\{upstream}', and there is no need for it.
++
+This suffix is also accepted when spelled in uppercase, and means the same
+thing no matter the case.
 
 '<rev>{caret}', e.g. 'HEAD{caret}, v1.5.1{caret}0'::
   A suffix '{caret}' to a revision parameter means the first parent of
@@ -291,7 +295,7 @@
 The 'r1{caret}!' notation includes commit 'r1' but excludes all of its parents.
 By itself, this notation denotes the single commit 'r1'.
 
-The '<rev>{caret}-{<n>}' notation includes '<rev>' but excludes the <n>th
+The '<rev>{caret}-<n>' notation includes '<rev>' but excludes the <n>th
 parent (i.e. a shorthand for '<rev>{caret}<n>..<rev>'), with '<n>' = 1 if
 not given. This is typically useful for merge commits where you
 can just pass '<commit>{caret}-' to get all the commits in the branch
@@ -333,7 +337,7 @@
   as giving commit '<rev>' and then all its parents prefixed with
   '{caret}' to exclude them (and their ancestors).
 
-'<rev>{caret}-{<n>}', e.g. 'HEAD{caret}-, HEAD{caret}-2'::
+'<rev>{caret}-<n>', e.g. 'HEAD{caret}-, HEAD{caret}-2'::
 	Equivalent to '<rev>{caret}<n>..<rev>', with '<n>' = 1 if not
 	given.
 
diff --git a/Documentation/technical/api-sha1-array.txt b/Documentation/technical/api-oid-array.txt
similarity index 61%
rename from Documentation/technical/api-sha1-array.txt
rename to Documentation/technical/api-oid-array.txt
index dcc5294..b0c11f8 100644
--- a/Documentation/technical/api-sha1-array.txt
+++ b/Documentation/technical/api-oid-array.txt
@@ -1,7 +1,7 @@
-sha1-array API
+oid-array API
 ==============
 
-The sha1-array API provides storage and manipulation of sets of SHA-1
+The oid-array API provides storage and manipulation of sets of object
 identifiers. The emphasis is on storage and processing efficiency,
 making them suitable for large lists. Note that the ordering of items is
 not preserved over some operations.
@@ -9,10 +9,10 @@
 Data Structures
 ---------------
 
-`struct sha1_array`::
+`struct oid_array`::
 
-	A single array of SHA-1 hashes. This should be initialized by
-	assignment from `SHA1_ARRAY_INIT`.  The `sha1` member contains
+	A single array of object IDs. This should be initialized by
+	assignment from `OID_ARRAY_INIT`.  The `oid` member contains
 	the actual data. The `nr` member contains the number of items in
 	the set.  The `alloc` and `sorted` members are used internally,
 	and should not be needed by API callers.
@@ -20,22 +20,22 @@
 Functions
 ---------
 
-`sha1_array_append`::
-	Add an item to the set. The sha1 will be placed at the end of
+`oid_array_append`::
+	Add an item to the set. The object ID will be placed at the end of
 	the array (but note that some operations below may lose this
 	ordering).
 
-`sha1_array_lookup`::
-	Perform a binary search of the array for a specific sha1.
+`oid_array_lookup`::
+	Perform a binary search of the array for a specific object ID.
 	If found, returns the offset (in number of elements) of the
-	sha1. If not found, returns a negative integer. If the array is
-	not sorted, this function has the side effect of sorting it.
+	object ID. If not found, returns a negative integer. If the array
+	is not sorted, this function has the side effect of sorting it.
 
-`sha1_array_clear`::
+`oid_array_clear`::
 	Free all memory associated with the array and return it to the
 	initial, empty state.
 
-`sha1_array_for_each_unique`::
+`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
@@ -47,25 +47,25 @@
 --------
 
 -----------------------------------------
-int print_callback(const unsigned char sha1[20],
+int print_callback(const struct object_id *oid,
 		    void *data)
 {
-	printf("%s\n", sha1_to_hex(sha1));
+	printf("%s\n", oid_to_hex(oid));
 	return 0; /* always continue */
 }
 
 void some_func(void)
 {
-	struct sha1_array hashes = SHA1_ARRAY_INIT;
-	unsigned char sha1[20];
+	struct sha1_array hashes = OID_ARRAY_INIT;
+	struct object_id oid;
 
 	/* Read objects into our set */
-	while (read_object_from_stdin(sha1))
-		sha1_array_append(&hashes, sha1);
+	while (read_object_from_stdin(oid.hash))
+		oid_array_append(&hashes, &oid);
 
 	/* Check if some objects are in our set */
-	while (read_object_from_stdin(sha1)) {
-		if (sha1_array_lookup(&hashes, sha1) >= 0)
+	while (read_object_from_stdin(oid.hash)) {
+		if (oid_array_lookup(&hashes, &oid) >= 0)
 			printf("it's in there!\n");
 
 	/*
@@ -75,6 +75,6 @@
 	 * Instead, this will sort once and then skip duplicates
 	 * in linear time.
 	 */
-	sha1_array_for_each_unique(&hashes, print_callback, NULL);
+	oid_array_for_each_unique(&hashes, print_callback, NULL);
 }
 -----------------------------------------
diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt
index c59ac99..5b0ba3e 100644
--- a/Documentation/technical/pack-protocol.txt
+++ b/Documentation/technical/pack-protocol.txt
@@ -351,14 +351,19 @@
 multi_ack_detailed is enabled. The server always sends NAK after 'done'
 if there is no common base found.
 
+Instead of 'ACK' or 'NAK', the server may send an error message (for
+example, if it does not recognize an object in a 'want' line received
+from the client).
+
 Then the server will start sending its packfile data.
 
 ----
-  server-response = *ack_multi ack / nak
+  server-response = *ack_multi ack / nak / error-line
   ack_multi       = PKT-LINE("ACK" SP obj-id ack_status)
   ack_status      = "continue" / "common" / "ready"
   ack             = PKT-LINE("ACK" SP obj-id)
   nak             = PKT-LINE("NAK")
+  error-line     =  PKT-LINE("ERR" SP explanation-text)
 ----
 
 A simple clone may look like this (with no 'have' lines):
diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index 817d1cf..c9f6bc6 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 GVF=GIT-VERSION-FILE
-DEF_VER=v2.12.GIT
+DEF_VER=v2.13.0-rc2
 
 LF='
 '
diff --git a/Makefile b/Makefile
index 9f8b35a..e35542e 100644
--- a/Makefile
+++ b/Makefile
@@ -626,10 +626,12 @@
 TEST_PROGRAMS_NEED_X += test-match-trees
 TEST_PROGRAMS_NEED_X += test-mergesort
 TEST_PROGRAMS_NEED_X += test-mktemp
+TEST_PROGRAMS_NEED_X += test-online-cpus
 TEST_PROGRAMS_NEED_X += test-parse-options
 TEST_PROGRAMS_NEED_X += test-path-utils
 TEST_PROGRAMS_NEED_X += test-prio-queue
 TEST_PROGRAMS_NEED_X += test-read-cache
+TEST_PROGRAMS_NEED_X += test-ref-store
 TEST_PROGRAMS_NEED_X += test-regex
 TEST_PROGRAMS_NEED_X += test-revision-walking
 TEST_PROGRAMS_NEED_X += test-run-command
@@ -637,6 +639,7 @@
 TEST_PROGRAMS_NEED_X += test-sha1
 TEST_PROGRAMS_NEED_X += test-sha1-array
 TEST_PROGRAMS_NEED_X += test-sigchain
+TEST_PROGRAMS_NEED_X += test-strcmp-offset
 TEST_PROGRAMS_NEED_X += test-string-list
 TEST_PROGRAMS_NEED_X += test-submodule-config
 TEST_PROGRAMS_NEED_X += test-subprocess
@@ -814,6 +817,7 @@
 LIB_OBJS += refs.o
 LIB_OBJS += refs/files-backend.o
 LIB_OBJS += refs/iterator.o
+LIB_OBJS += refs/ref-cache.o
 LIB_OBJS += ref-filter.o
 LIB_OBJS += remote.o
 LIB_OBJS += replace_object.o
@@ -1851,6 +1855,7 @@
 
 perl/PM.stamp: FORCE
 	@$(FIND) perl -type f -name '*.pm' | sort >$@+ && \
+	$(PERL_PATH) -V >>$@+ && \
 	{ cmp $@+ $@ >/dev/null 2>/dev/null || mv $@+ $@; } && \
 	$(RM) $@+
 
@@ -2348,9 +2353,17 @@
 C_SOURCES = $(patsubst %.o,%.c,$(C_OBJ))
 %.cocci.patch: %.cocci $(C_SOURCES)
 	@echo '    ' SPATCH $<; \
+	ret=0; \
 	for f in $(C_SOURCES); do \
-		$(SPATCH) --sp-file $< $$f $(SPATCH_FLAGS); \
-	done >$@ 2>$@.log; \
+		$(SPATCH) --sp-file $< $$f $(SPATCH_FLAGS) || \
+			{ ret=$$?; break; }; \
+	done >$@+ 2>$@.log; \
+	if test $$ret != 0; \
+	then \
+		cat $@.log; \
+		exit 1; \
+	fi; \
+	mv $@+ $@; \
 	if test -s $@; \
 	then \
 		echo '    ' SPATCH result: $@; \
diff --git a/bisect.c b/bisect.c
index 30808ca..08c9fb7 100644
--- a/bisect.c
+++ b/bisect.c
@@ -12,8 +12,8 @@
 #include "sha1-array.h"
 #include "argv-array.h"
 
-static struct sha1_array good_revs;
-static struct sha1_array skipped_revs;
+static struct oid_array good_revs;
+static struct oid_array skipped_revs;
 
 static struct object_id *current_bad_oid;
 
@@ -200,6 +200,7 @@
 {
 	struct commit_list *p;
 	struct commit_dist *array = xcalloc(nr, sizeof(*array));
+	struct strbuf buf = STRBUF_INIT;
 	int cnt, i;
 
 	for (p = list, cnt = 0; p; p = p->next) {
@@ -217,17 +218,18 @@
 	}
 	QSORT(array, cnt, compare_commit_dist);
 	for (p = list, i = 0; i < cnt; i++) {
-		char buf[100]; /* enough for dist=%d */
 		struct object *obj = &(array[i].commit->object);
 
-		snprintf(buf, sizeof(buf), "dist=%d", array[i].distance);
-		add_name_decoration(DECORATION_NONE, buf, obj);
+		strbuf_reset(&buf);
+		strbuf_addf(&buf, "dist=%d", array[i].distance);
+		add_name_decoration(DECORATION_NONE, buf.buf, obj);
 
 		p->item = array[i].commit;
 		p = p->next;
 	}
 	if (p)
 		p->next = NULL;
+	strbuf_release(&buf);
 	free(array);
 	return list;
 }
@@ -413,9 +415,9 @@
 		current_bad_oid = xmalloc(sizeof(*current_bad_oid));
 		oidcpy(current_bad_oid, oid);
 	} else if (starts_with(refname, good_prefix.buf)) {
-		sha1_array_append(&good_revs, oid->hash);
+		oid_array_append(&good_revs, oid);
 	} else if (starts_with(refname, "skip-")) {
-		sha1_array_append(&skipped_revs, oid->hash);
+		oid_array_append(&skipped_revs, oid);
 	}
 
 	strbuf_release(&good_prefix);
@@ -430,6 +432,7 @@
 
 static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
 static GIT_PATH_FUNC(git_path_bisect_expected_rev, "BISECT_EXPECTED_REV")
+static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
 
 static void read_bisect_paths(struct argv_array *array)
 {
@@ -451,13 +454,13 @@
 	fclose(fp);
 }
 
-static char *join_sha1_array_hex(struct sha1_array *array, char delim)
+static char *join_sha1_array_hex(struct oid_array *array, char delim)
 {
 	struct strbuf joined_hexs = STRBUF_INIT;
 	int i;
 
 	for (i = 0; i < array->nr; i++) {
-		strbuf_addstr(&joined_hexs, sha1_to_hex(array->sha1[i]));
+		strbuf_addstr(&joined_hexs, oid_to_hex(array->oid + i));
 		if (i + 1 < array->nr)
 			strbuf_addch(&joined_hexs, delim);
 	}
@@ -499,8 +502,7 @@
 	while (list) {
 		struct commit_list *next = list->next;
 		list->next = NULL;
-		if (0 <= sha1_array_lookup(&skipped_revs,
-					   list->item->object.oid.hash)) {
+		if (0 <= oid_array_lookup(&skipped_revs, &list->item->object.oid)) {
 			if (skipped_first && !*skipped_first)
 				*skipped_first = 1;
 			/* Move current to tried list */
@@ -621,7 +623,7 @@
 	argv_array_pushf(&rev_argv, bad_format, oid_to_hex(current_bad_oid));
 	for (i = 0; i < good_revs.nr; i++)
 		argv_array_pushf(&rev_argv, good_format,
-				 sha1_to_hex(good_revs.sha1[i]));
+				 oid_to_hex(good_revs.oid + i));
 	argv_array_push(&rev_argv, "--");
 	if (read_paths)
 		read_bisect_paths(&rev_argv);
@@ -682,7 +684,7 @@
 
 static int bisect_checkout(const unsigned char *bisect_rev, int no_checkout)
 {
-	char bisect_rev_hex[GIT_SHA1_HEXSZ + 1];
+	char bisect_rev_hex[GIT_MAX_HEXSZ + 1];
 
 	memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), GIT_SHA1_HEXSZ + 1);
 	update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
@@ -701,11 +703,11 @@
 	return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
 }
 
-static struct commit *get_commit_reference(const unsigned char *sha1)
+static struct commit *get_commit_reference(const struct object_id *oid)
 {
-	struct commit *r = lookup_commit_reference(sha1);
+	struct commit *r = lookup_commit_reference(oid->hash);
 	if (!r)
-		die(_("Not a valid commit name %s"), sha1_to_hex(sha1));
+		die(_("Not a valid commit name %s"), oid_to_hex(oid));
 	return r;
 }
 
@@ -715,9 +717,9 @@
 	int i, n = 0;
 
 	ALLOC_ARRAY(rev, 1 + good_revs.nr);
-	rev[n++] = get_commit_reference(current_bad_oid->hash);
+	rev[n++] = get_commit_reference(current_bad_oid);
 	for (i = 0; i < good_revs.nr; i++)
-		rev[n++] = get_commit_reference(good_revs.sha1[i]);
+		rev[n++] = get_commit_reference(good_revs.oid + i);
 	*rev_nr = n;
 
 	return rev;
@@ -754,9 +756,9 @@
 	exit(1);
 }
 
-static void handle_skipped_merge_base(const unsigned char *mb)
+static void handle_skipped_merge_base(const struct object_id *mb)
 {
-	char *mb_hex = sha1_to_hex(mb);
+	char *mb_hex = oid_to_hex(mb);
 	char *bad_hex = oid_to_hex(current_bad_oid);
 	char *good_hex = join_sha1_array_hex(&good_revs, ' ');
 
@@ -787,16 +789,16 @@
 	result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1);
 
 	for (; result; result = result->next) {
-		const unsigned char *mb = result->item->object.oid.hash;
-		if (!hashcmp(mb, current_bad_oid->hash)) {
+		const struct object_id *mb = &result->item->object.oid;
+		if (!oidcmp(mb, current_bad_oid)) {
 			handle_bad_merge_base();
-		} else if (0 <= sha1_array_lookup(&good_revs, mb)) {
+		} else if (0 <= oid_array_lookup(&good_revs, mb)) {
 			continue;
-		} else if (0 <= sha1_array_lookup(&skipped_revs, mb)) {
+		} else if (0 <= oid_array_lookup(&skipped_revs, mb)) {
 			handle_skipped_merge_base(mb);
 		} else {
 			printf(_("Bisecting: a merge base must be tested\n"));
-			exit(bisect_checkout(mb, no_checkout));
+			exit(bisect_checkout(mb->hash, no_checkout));
 		}
 	}
 
@@ -905,7 +907,7 @@
 void read_bisect_terms(const char **read_bad, const char **read_good)
 {
 	struct strbuf str = STRBUF_INIT;
-	const char *filename = git_path("BISECT_TERMS");
+	const char *filename = git_path_bisect_terms();
 	FILE *fp = fopen(filename, "r");
 
 	if (!fp) {
diff --git a/branch.c b/branch.c
index 5c12036..ad5a229 100644
--- a/branch.c
+++ b/branch.c
@@ -234,7 +234,7 @@
 {
 	struct commit *commit;
 	unsigned char sha1[20];
-	char *real_ref, msg[PATH_MAX + 20];
+	char *real_ref;
 	struct strbuf ref = STRBUF_INIT;
 	int forcing = 0;
 	int dont_change_ref = 0;
@@ -290,19 +290,18 @@
 		die(_("Not a valid branch point: '%s'."), start_name);
 	hashcpy(sha1, commit->object.oid.hash);
 
-	if (forcing)
-		snprintf(msg, sizeof msg, "branch: Reset to %s",
-			 start_name);
-	else if (!dont_change_ref)
-		snprintf(msg, sizeof msg, "branch: Created from %s",
-			 start_name);
-
 	if (reflog)
 		log_all_ref_updates = LOG_REFS_NORMAL;
 
 	if (!dont_change_ref) {
 		struct ref_transaction *transaction;
 		struct strbuf err = STRBUF_INIT;
+		char *msg;
+
+		if (forcing)
+			msg = xstrfmt("branch: Reset to %s", start_name);
+		else
+			msg = xstrfmt("branch: Created from %s", start_name);
 
 		transaction = ref_transaction_begin(&err);
 		if (!transaction ||
@@ -313,6 +312,7 @@
 			die("%s", err.buf);
 		ref_transaction_free(transaction);
 		strbuf_release(&err);
+		free(msg);
 	}
 
 	if (real_ref && track)
diff --git a/builtin/am.c b/builtin/am.c
index f7a7a97..a95dd8b 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -134,17 +134,15 @@
 };
 
 /**
- * Initializes am_state with the default values. The state directory is set to
- * dir.
+ * Initializes am_state with the default values.
  */
-static void am_state_init(struct am_state *state, const char *dir)
+static void am_state_init(struct am_state *state)
 {
 	int gpgsign;
 
 	memset(state, 0, sizeof(*state));
 
-	assert(dir);
-	state->dir = xstrdup(dir);
+	state->dir = git_pathdup("rebase-apply");
 
 	state->prec = 4;
 
@@ -762,14 +760,18 @@
 		mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
 
 		out = fopen(mail, "w");
-		if (!out)
+		if (!out) {
+			if (in != stdin)
+				fclose(in);
 			return error_errno(_("could not open '%s' for writing"),
 					   mail);
+		}
 
 		ret = fn(out, in, keep_cr);
 
 		fclose(out);
-		fclose(in);
+		if (in != stdin)
+			fclose(in);
 
 		if (ret)
 			return error(_("could not parse patch '%s'"), *paths);
@@ -1181,42 +1183,39 @@
 	exit(128);
 }
 
-static void am_signoff(struct strbuf *sb)
-{
-	char *cp;
-	struct strbuf mine = STRBUF_INIT;
-
-	/* Does it end with our own sign-off? */
-	strbuf_addf(&mine, "\n%s%s\n",
-		    sign_off_header,
-		    fmt_name(getenv("GIT_COMMITTER_NAME"),
-			     getenv("GIT_COMMITTER_EMAIL")));
-	if (mine.len < sb->len &&
-	    !strcmp(mine.buf, sb->buf + sb->len - mine.len))
-		goto exit; /* no need to duplicate */
-
-	/* Does it have any Signed-off-by: in the text */
-	for (cp = sb->buf;
-	     cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
-	     cp = strchr(cp, '\n')) {
-		if (sb->buf == cp || cp[-1] == '\n')
-			break;
-	}
-
-	strbuf_addstr(sb, mine.buf + !!cp);
-exit:
-	strbuf_release(&mine);
-}
-
 /**
  * Appends signoff to the "msg" field of the am_state.
  */
 static void am_append_signoff(struct am_state *state)
 {
+	char *cp;
+	struct strbuf mine = STRBUF_INIT;
 	struct strbuf sb = STRBUF_INIT;
 
 	strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
-	am_signoff(&sb);
+
+	/* our sign-off */
+	strbuf_addf(&mine, "\n%s%s\n",
+		    sign_off_header,
+		    fmt_name(getenv("GIT_COMMITTER_NAME"),
+			     getenv("GIT_COMMITTER_EMAIL")));
+
+	/* Does sb end with it already? */
+	if (mine.len < sb.len &&
+	    !strcmp(mine.buf, sb.buf + sb.len - mine.len))
+		goto exit; /* no need to duplicate */
+
+	/* Does it have any Signed-off-by: in the text */
+	for (cp = sb.buf;
+	     cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
+	     cp = strchr(cp, '\n')) {
+		if (sb.buf == cp || cp[-1] == '\n')
+			break;
+	}
+
+	strbuf_addstr(&sb, mine.buf + !!cp);
+exit:
+	strbuf_release(&mine);
 	state->msg = strbuf_detach(&sb, &state->msg_len);
 }
 
@@ -1321,9 +1320,6 @@
 	strbuf_addbuf(&msg, &mi.log_message);
 	strbuf_stripspace(&msg, 0);
 
-	if (state->signoff)
-		am_signoff(&msg);
-
 	assert(!state->author_name);
 	state->author_name = strbuf_detach(&author_name, NULL);
 
@@ -1848,6 +1844,9 @@
 			if (skip)
 				goto next; /* mail should be skipped */
 
+			if (state->signoff)
+				am_append_signoff(state);
+
 			write_author_script(state);
 			write_commit_msg(state);
 		}
@@ -2322,7 +2321,7 @@
 
 	git_config(git_am_config, NULL);
 
-	am_state_init(&state, git_path("rebase-apply"));
+	am_state_init(&state);
 
 	in_progress = am_in_progress(&state);
 	if (in_progress)
diff --git a/builtin/blame.c b/builtin/blame.c
index f7aa95f..07506a3 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -1890,7 +1890,7 @@
 	int cnt;
 	const char *cp;
 	struct origin *suspect = ent->suspect;
-	char hex[GIT_SHA1_HEXSZ + 1];
+	char hex[GIT_MAX_HEXSZ + 1];
 
 	oid_to_hex_r(hex, &suspect->commit->object.oid);
 	printf("%s %d %d %d\n",
@@ -1928,7 +1928,7 @@
 	const char *cp;
 	struct origin *suspect = ent->suspect;
 	struct commit_info ci;
-	char hex[GIT_SHA1_HEXSZ + 1];
+	char hex[GIT_MAX_HEXSZ + 1];
 	int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
 
 	get_commit_info(suspect->commit, &ci, 1);
diff --git a/builtin/branch.c b/builtin/branch.c
index 52688f2..48a513a 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -504,7 +504,7 @@
 	strbuf_release(&newsection);
 }
 
-static const char edit_description[] = "BRANCH_DESCRIPTION";
+static GIT_PATH_FUNC(edit_description, "EDIT_DESCRIPTION")
 
 static int edit_branch_description(const char *branch_name)
 {
@@ -519,9 +519,9 @@
 		      "  %s\n"
 		      "Lines starting with '%c' will be stripped.\n"),
 		    branch_name, comment_line_char);
-	write_file_buf(git_path(edit_description), buf.buf, buf.len);
+	write_file_buf(edit_description(), buf.buf, buf.len);
 	strbuf_reset(&buf);
-	if (launch_editor(git_path(edit_description), &buf, NULL)) {
+	if (launch_editor(edit_description(), &buf, NULL)) {
 		strbuf_release(&buf);
 		return -1;
 	}
@@ -562,7 +562,9 @@
 		OPT_SET_INT('r', "remotes",     &filter.kind, N_("act on remote-tracking branches"),
 			FILTER_REFS_REMOTES),
 		OPT_CONTAINS(&filter.with_commit, N_("print only branches that contain the commit")),
+		OPT_NO_CONTAINS(&filter.no_commit, N_("print only branches that don't contain the commit")),
 		OPT_WITH(&filter.with_commit, N_("print only branches that contain the commit")),
+		OPT_WITHOUT(&filter.no_commit, N_("print only branches that don't contain the commit")),
 		OPT__ABBREV(&filter.abbrev),
 
 		OPT_GROUP(N_("Specific git-branch actions:")),
@@ -618,7 +620,8 @@
 	if (!delete && !rename && !edit_description && !new_upstream && !unset_upstream && argc == 0)
 		list = 1;
 
-	if (filter.with_commit || filter.merge != REF_FILTER_MERGED_NONE || filter.points_at.nr)
+	if (filter.with_commit || filter.merge != REF_FILTER_MERGED_NONE || filter.points_at.nr ||
+	    filter.no_commit)
 		list = 1;
 
 	if (!!delete + !!rename + !!new_upstream +
diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 8b85cb8..1890d7a 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -401,10 +401,10 @@
 	struct expand_data *expand;
 };
 
-static int batch_object_cb(const unsigned char sha1[20], void *vdata)
+static int batch_object_cb(const struct object_id *oid, void *vdata)
 {
 	struct object_cb_data *data = vdata;
-	hashcpy(data->expand->oid.hash, sha1);
+	oidcpy(&data->expand->oid, oid);
 	batch_object_write(NULL, data->opt, data->expand);
 	return 0;
 }
@@ -413,7 +413,7 @@
 			      const char *path,
 			      void *data)
 {
-	sha1_array_append(data, oid->hash);
+	oid_array_append(data, oid);
 	return 0;
 }
 
@@ -422,7 +422,7 @@
 			       uint32_t pos,
 			       void *data)
 {
-	sha1_array_append(data, oid->hash);
+	oid_array_append(data, oid);
 	return 0;
 }
 
@@ -462,7 +462,7 @@
 		data.info.typep = &data.type;
 
 	if (opt->all_objects) {
-		struct sha1_array sa = SHA1_ARRAY_INIT;
+		struct oid_array sa = OID_ARRAY_INIT;
 		struct object_cb_data cb;
 
 		for_each_loose_object(batch_loose_object, &sa, 0);
@@ -470,9 +470,9 @@
 
 		cb.opt = opt;
 		cb.expand = &data;
-		sha1_array_for_each_unique(&sa, batch_object_cb, &cb);
+		oid_array_for_each_unique(&sa, batch_object_cb, &cb);
 
-		sha1_array_clear(&sa);
+		oid_array_clear(&sa);
 		return 0;
 	}
 
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 3ecc47b..bfa5419 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -908,11 +908,10 @@
 static const char *unique_tracking_name(const char *name, struct object_id *oid)
 {
 	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
-	char src_ref[PATH_MAX];
-	snprintf(src_ref, PATH_MAX, "refs/heads/%s", name);
-	cb_data.src_ref = src_ref;
+	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
+	free(cb_data.src_ref);
 	if (cb_data.unique)
 		return cb_data.dst_ref;
 	free(cb_data.dst_ref);
diff --git a/builtin/clone.c b/builtin/clone.c
index b4c929b..de85b85 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -39,7 +39,7 @@
 };
 
 static int option_no_checkout, option_bare, option_mirror, option_single_branch = -1;
-static int option_local = -1, option_no_hardlinks, option_shared, option_recursive;
+static int option_local = -1, option_no_hardlinks, option_shared;
 static int option_shallow_submodules;
 static int deepen;
 static char *option_template, *option_depth, *option_since;
@@ -56,6 +56,21 @@
 static struct string_list option_optional_reference = STRING_LIST_INIT_NODUP;
 static int option_dissociate;
 static int max_jobs = -1;
+static struct string_list option_recurse_submodules = STRING_LIST_INIT_NODUP;
+
+static int recurse_submodules_cb(const struct option *opt,
+				 const char *arg, int unset)
+{
+	if (unset)
+		string_list_clear((struct string_list *)opt->value, 0);
+	else if (arg)
+		string_list_append((struct string_list *)opt->value, arg);
+	else
+		string_list_append((struct string_list *)opt->value,
+				   (const char *)opt->defval);
+
+	return 0;
+}
 
 static struct option builtin_clone_options[] = {
 	OPT__VERBOSITY(&option_verbosity),
@@ -74,10 +89,13 @@
 		    N_("don't use local hardlinks, always copy")),
 	OPT_BOOL('s', "shared", &option_shared,
 		    N_("setup as shared repository")),
-	OPT_BOOL(0, "recursive", &option_recursive,
-		    N_("initialize submodules in the clone")),
-	OPT_BOOL(0, "recurse-submodules", &option_recursive,
-		    N_("initialize submodules in the clone")),
+	{ OPTION_CALLBACK, 0, "recursive", &option_recurse_submodules,
+	  N_("pathspec"), N_("initialize submodules in the clone"),
+	  PARSE_OPT_OPTARG | PARSE_OPT_HIDDEN, recurse_submodules_cb,
+	  (intptr_t)"." },
+	{ OPTION_CALLBACK, 0, "recurse-submodules", &option_recurse_submodules,
+	  N_("pathspec"), N_("initialize submodules in the clone"),
+	  PARSE_OPT_OPTARG, recurse_submodules_cb, (intptr_t)"." },
 	OPT_INTEGER('j', "jobs", &max_jobs,
 		    N_("number of submodules cloned in parallel")),
 	OPT_STRING(0, "template", &option_template, N_("template-directory"),
@@ -733,7 +751,7 @@
 	err |= run_hook_le(NULL, "post-checkout", sha1_to_hex(null_sha1),
 			   oid_to_hex(&oid), "1", NULL);
 
-	if (!err && option_recursive) {
+	if (!err && (option_recurse_submodules.nr > 0)) {
 		struct argv_array args = ARGV_ARRAY_INIT;
 		argv_array_pushl(&args, "submodule", "update", "--init", "--recursive", NULL);
 
@@ -957,7 +975,25 @@
 			fprintf(stderr, _("Cloning into '%s'...\n"), dir);
 	}
 
-	if (option_recursive) {
+	if (option_recurse_submodules.nr > 0) {
+		struct string_list_item *item;
+		struct strbuf sb = STRBUF_INIT;
+
+		/* remove duplicates */
+		string_list_sort(&option_recurse_submodules);
+		string_list_remove_duplicates(&option_recurse_submodules, 0);
+
+		/*
+		 * NEEDSWORK: In a multi-working-tree world, this needs to be
+		 * set in the per-worktree config.
+		 */
+		for_each_string_list_item(item, &option_recurse_submodules) {
+			strbuf_addf(&sb, "submodule.active=%s",
+				    item->string);
+			string_list_append(&option_config,
+					   strbuf_detach(&sb, NULL));
+		}
+
 		if (option_required_reference.nr &&
 		    option_optional_reference.nr)
 			die(_("clone --recursive is not compatible with "
diff --git a/builtin/commit.c b/builtin/commit.c
index 4e288bc..1d805f5 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -821,9 +821,9 @@
 					"If this is not correct, please remove the file\n"
 					"	%s\n"
 					"and try again.\n"),
-				git_path(whence == FROM_MERGE
-					 ? "MERGE_HEAD"
-					 : "CHERRY_PICK_HEAD"));
+				whence == FROM_MERGE ?
+					git_path_merge_head() :
+					git_path_cherry_pick_head());
 		}
 
 		fprintf(s->fp, "\n");
@@ -1404,7 +1404,7 @@
 
 static const char *implicit_ident_advice(void)
 {
-	char *user_config = expand_user_path("~/.gitconfig");
+	char *user_config = expand_user_path("~/.gitconfig", 0);
 	char *xdg_config = xdg_config_home("config");
 	int config_exists = file_exists(user_config) || file_exists(xdg_config);
 
diff --git a/builtin/config.c b/builtin/config.c
index 4f49a0e..3a554ad 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -26,7 +26,8 @@
 static struct git_config_source given_config_source;
 static int actions, types;
 static int end_null;
-static int respect_includes = -1;
+static int respect_includes_opt = -1;
+static struct config_options config_options;
 static int show_origin;
 
 #define ACTION_GET (1<<0)
@@ -81,7 +82,7 @@
 	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, N_("respect include directives on lookup")),
+	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_END(),
 };
@@ -242,7 +243,7 @@
 	}
 
 	git_config_with_options(collect_config, &values,
-				&given_config_source, respect_includes);
+				&given_config_source, &config_options);
 
 	ret = !values.nr;
 
@@ -320,7 +321,7 @@
 	get_color_found = 0;
 	parsed_color[0] = '\0';
 	git_config_with_options(git_get_color_config, NULL,
-				&given_config_source, respect_includes);
+				&given_config_source, &config_options);
 
 	if (!get_color_found && def_color) {
 		if (color_parse(def_color, parsed_color) < 0)
@@ -352,7 +353,7 @@
 	get_diff_color_found = -1;
 	get_color_ui_found = -1;
 	git_config_with_options(git_get_colorbool_config, NULL,
-				&given_config_source, respect_includes);
+				&given_config_source, &config_options);
 
 	if (get_colorbool_found < 0) {
 		if (!strcmp(get_colorbool_slot, "color.diff"))
@@ -441,7 +442,7 @@
 	}
 
 	git_config_with_options(urlmatch_config_entry, &config,
-				&given_config_source, respect_includes);
+				&given_config_source, &config_options);
 
 	ret = !values.nr;
 
@@ -502,7 +503,7 @@
 	}
 
 	if (use_global_config) {
-		char *user_config = expand_user_path("~/.gitconfig");
+		char *user_config = expand_user_path("~/.gitconfig", 0);
 		char *xdg_config = xdg_config_home("config");
 
 		if (!user_config)
@@ -530,8 +531,10 @@
 				prefix_filename(prefix, given_config_source.file);
 	}
 
-	if (respect_includes == -1)
-		respect_includes = !given_config_source.file;
+	if (respect_includes_opt == -1)
+		config_options.respect_includes = !given_config_source.file;
+	else
+		config_options.respect_includes = respect_includes_opt;
 
 	if (end_null) {
 		term = '\0';
@@ -578,7 +581,7 @@
 		check_argc(argc, 0, 0);
 		if (git_config_with_options(show_all_config, NULL,
 					    &given_config_source,
-					    respect_includes) < 0) {
+					    &config_options) < 0) {
 			if (given_config_source.file)
 				die_errno("unable to read config file '%s'",
 					  given_config_source.file);
@@ -597,8 +600,9 @@
 		if (given_config_source.blob)
 			die("editing blobs is not supported");
 		git_config(git_default_config, NULL);
-		config_file = xstrdup(given_config_source.file ?
-				      given_config_source.file : git_path("config"));
+		config_file = given_config_source.file ?
+				xstrdup(given_config_source.file) :
+				git_pathdup("config");
 		if (use_global_config) {
 			int fd = open(config_file, O_CREAT | O_EXCL | O_WRONLY, 0666);
 			if (fd >= 0) {
diff --git a/builtin/describe.c b/builtin/describe.c
index 45adbf6..a5cd8c5 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -50,7 +50,7 @@
 };
 
 static const char *prio_names[] = {
-	"head", "lightweight", "annotated",
+	N_("head"), N_("lightweight"), N_("annotated"),
 };
 
 static int commit_name_cmp(const struct commit_name *cn1,
@@ -395,10 +395,19 @@
 	free_commit_list(list);
 
 	if (debug) {
+		static int label_width = -1;
+		if (label_width < 0) {
+			int i, w;
+			for (i = 0; i < ARRAY_SIZE(prio_names); i++) {
+				w = strlen(_(prio_names[i]));
+				if (label_width < w)
+					label_width = w;
+			}
+		}
 		for (cur_match = 0; cur_match < match_cnt; cur_match++) {
 			struct possible_tag *t = &all_matches[cur_match];
-			fprintf(stderr, " %-11s %8d %s\n",
-				prio_names[t->name->prio],
+			fprintf(stderr, " %-*s %8d %s\n",
+				label_width, _(prio_names[t->name->prio]),
 				t->depth, t->name->path);
 		}
 		fprintf(stderr, _("traversed %lu commits\n"), seen_commits);
diff --git a/builtin/diff.c b/builtin/diff.c
index 3d64b85..d184aaf 100644
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -21,7 +21,7 @@
 #define DIFF_NO_INDEX_IMPLICIT 2
 
 struct blobinfo {
-	unsigned char sha1[20];
+	struct object_id oid;
 	const char *name;
 	unsigned mode;
 };
@@ -31,22 +31,22 @@
 
 static void stuff_change(struct diff_options *opt,
 			 unsigned old_mode, unsigned new_mode,
-			 const unsigned char *old_sha1,
-			 const unsigned char *new_sha1,
-			 int old_sha1_valid,
-			 int new_sha1_valid,
+			 const struct object_id *old_oid,
+			 const struct object_id *new_oid,
+			 int old_oid_valid,
+			 int new_oid_valid,
 			 const char *old_name,
 			 const char *new_name)
 {
 	struct diff_filespec *one, *two;
 
-	if (!is_null_sha1(old_sha1) && !is_null_sha1(new_sha1) &&
-	    !hashcmp(old_sha1, new_sha1) && (old_mode == new_mode))
+	if (!is_null_oid(old_oid) && !is_null_oid(new_oid) &&
+	    !oidcmp(old_oid, new_oid) && (old_mode == new_mode))
 		return;
 
 	if (DIFF_OPT_TST(opt, REVERSE_DIFF)) {
 		SWAP(old_mode, new_mode);
-		SWAP(old_sha1, new_sha1);
+		SWAP(old_oid, new_oid);
 		SWAP(old_name, new_name);
 	}
 
@@ -57,8 +57,8 @@
 
 	one = alloc_filespec(old_name);
 	two = alloc_filespec(new_name);
-	fill_filespec(one, old_sha1, old_sha1_valid, old_mode);
-	fill_filespec(two, new_sha1, new_sha1_valid, new_mode);
+	fill_filespec(one, old_oid->hash, old_oid_valid, old_mode);
+	fill_filespec(two, new_oid->hash, new_oid_valid, new_mode);
 
 	diff_queue(&diff_queued_diff, one, two);
 }
@@ -89,7 +89,7 @@
 
 	stuff_change(&revs->diffopt,
 		     blob[0].mode, canon_mode(st.st_mode),
-		     blob[0].sha1, null_sha1,
+		     &blob[0].oid, &null_oid,
 		     1, 0,
 		     path, path);
 	diffcore_std(&revs->diffopt);
@@ -114,7 +114,7 @@
 
 	stuff_change(&revs->diffopt,
 		     blob[0].mode, blob[1].mode,
-		     blob[0].sha1, blob[1].sha1,
+		     &blob[0].oid, &blob[1].oid,
 		     1, 1,
 		     blob[0].name, blob[1].name);
 	diffcore_std(&revs->diffopt);
@@ -160,7 +160,7 @@
 			     struct object_array_entry *ent0,
 			     struct object_array_entry *ent1)
 {
-	const unsigned char *(sha1[2]);
+	const struct object_id *(oid[2]);
 	int swap = 0;
 
 	if (argc > 1)
@@ -172,9 +172,9 @@
 	 */
 	if (ent1->item->flags & UNINTERESTING)
 		swap = 1;
-	sha1[swap] = ent0->item->oid.hash;
-	sha1[1 - swap] = ent1->item->oid.hash;
-	diff_tree_sha1(sha1[0], sha1[1], "", &revs->diffopt);
+	oid[swap] = &ent0->item->oid;
+	oid[1 - swap] = &ent1->item->oid;
+	diff_tree_sha1(oid[0]->hash, oid[1]->hash, "", &revs->diffopt);
 	log_tree_diff_flush(revs);
 	return 0;
 }
@@ -184,7 +184,7 @@
 				 struct object_array_entry *ent,
 				 int ents)
 {
-	struct sha1_array parents = SHA1_ARRAY_INIT;
+	struct oid_array parents = OID_ARRAY_INIT;
 	int i;
 
 	if (argc > 1)
@@ -193,10 +193,10 @@
 	if (!revs->dense_combined_merges && !revs->combine_merges)
 		revs->dense_combined_merges = revs->combine_merges = 1;
 	for (i = 1; i < ents; i++)
-		sha1_array_append(&parents, ent[i].item->oid.hash);
+		oid_array_append(&parents, &ent[i].item->oid);
 	diff_tree_combined(ent[0].item->oid.hash, &parents,
 			   revs->dense_combined_merges, revs);
-	sha1_array_clear(&parents);
+	oid_array_clear(&parents);
 	return 0;
 }
 
@@ -408,7 +408,7 @@
 		} else if (obj->type == OBJ_BLOB) {
 			if (2 <= blobs)
 				die(_("more than two blobs given: '%s'"), name);
-			hashcpy(blob[blobs].sha1, obj->oid.hash);
+			hashcpy(blob[blobs].oid.hash, obj->oid.hash);
 			blob[blobs].name = name;
 			blob[blobs].mode = entry->mode;
 			blobs++;
diff --git a/builtin/difftool.c b/builtin/difftool.c
index 25e54ad..1354d0e 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -297,6 +297,19 @@
 	return data;
 }
 
+static int checkout_path(unsigned mode, struct object_id *oid,
+			 const char *path, const struct checkout *state)
+{
+	struct cache_entry *ce;
+	int ret;
+
+	ce = make_cache_entry(mode, oid->hash, path, 0, 0);
+	ret = checkout_entry(ce, state, NULL);
+
+	free(ce);
+	return ret;
+}
+
 static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 			int argc, const char **argv)
 {
@@ -305,8 +318,8 @@
 	struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
 	struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
 	struct strbuf wtdir = STRBUF_INIT;
+	char *lbase_dir, *rbase_dir;
 	size_t ldir_len, rdir_len, wtdir_len;
-	struct cache_entry *ce = xcalloc(1, sizeof(ce) + PATH_MAX + 1);
 	const char *workdir, *tmp;
 	int ret = 0, i;
 	FILE *fp;
@@ -339,11 +352,11 @@
 	memset(&wtindex, 0, sizeof(wtindex));
 
 	memset(&lstate, 0, sizeof(lstate));
-	lstate.base_dir = ldir.buf;
+	lstate.base_dir = lbase_dir = xstrdup(ldir.buf);
 	lstate.base_dir_len = ldir.len;
 	lstate.force = 1;
 	memset(&rstate, 0, sizeof(rstate));
-	rstate.base_dir = rdir.buf;
+	rstate.base_dir = rbase_dir = xstrdup(rdir.buf);
 	rstate.base_dir_len = rdir.len;
 	rstate.force = 1;
 
@@ -377,7 +390,6 @@
 		struct object_id loid, roid;
 		char status;
 		const char *src_path, *dst_path;
-		size_t src_path_len, dst_path_len;
 
 		if (starts_with(info.buf, "::"))
 			die(N_("combined diff formats('-c' and '--cc') are "
@@ -390,17 +402,14 @@
 		if (strbuf_getline_nul(&lpath, fp))
 			break;
 		src_path = lpath.buf;
-		src_path_len = lpath.len;
 
 		i++;
 		if (status != 'C' && status != 'R') {
 			dst_path = src_path;
-			dst_path_len = src_path_len;
 		} else {
 			if (strbuf_getline_nul(&rpath, fp))
 				break;
 			dst_path = rpath.buf;
-			dst_path_len = rpath.len;
 		}
 
 		if (S_ISGITLINK(lmode) || S_ISGITLINK(rmode)) {
@@ -430,11 +439,7 @@
 		}
 
 		if (lmode && status != 'C') {
-			ce->ce_mode = lmode;
-			oidcpy(&ce->oid, &loid);
-			strcpy(ce->name, src_path);
-			ce->ce_namelen = src_path_len;
-			if (checkout_entry(ce, &lstate, NULL))
+			if (checkout_path(lmode, &loid, src_path, &lstate))
 				return error("could not write '%s'", src_path);
 		}
 
@@ -451,11 +456,7 @@
 			hashmap_add(&working_tree_dups, entry);
 
 			if (!use_wt_file(workdir, dst_path, &roid)) {
-				ce->ce_mode = rmode;
-				oidcpy(&ce->oid, &roid);
-				strcpy(ce->name, dst_path);
-				ce->ce_namelen = dst_path_len;
-				if (checkout_entry(ce, &rstate, NULL))
+				if (checkout_path(rmode, &roid, dst_path, &rstate))
 					return error("could not write '%s'",
 						     dst_path);
 			} else if (!is_null_oid(&roid)) {
@@ -625,7 +626,8 @@
 		exit_cleanup(tmpdir, rc);
 
 finish:
-	free(ce);
+	free(lbase_dir);
+	free(rbase_dir);
 	strbuf_release(&ldir);
 	strbuf_release(&rdir);
 	strbuf_release(&wtdir);
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index 2a1c1c2..366b9d1 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -50,7 +50,7 @@
 	char **pack_lockfile_ptr = NULL;
 	struct child_process *conn;
 	struct fetch_pack_args args;
-	struct sha1_array shallow = SHA1_ARRAY_INIT;
+	struct oid_array shallow = OID_ARRAY_INIT;
 	struct string_list deepen_not = STRING_LIST_INIT_DUP;
 
 	packet_trace_identity("fetch-pack");
diff --git a/builtin/fetch.c b/builtin/fetch.c
index b5ad09d..5f2c2ab 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -421,7 +421,7 @@
 			struct ref *ref,
 			int check_old)
 {
-	char msg[1024];
+	char *msg;
 	char *rla = getenv("GIT_REFLOG_ACTION");
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
@@ -431,7 +431,7 @@
 		return 0;
 	if (!rla)
 		rla = default_rla.buf;
-	snprintf(msg, sizeof(msg), "%s: %s", rla, action);
+	msg = xstrfmt("%s: %s", rla, action);
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
@@ -449,11 +449,13 @@
 
 	ref_transaction_free(transaction);
 	strbuf_release(&err);
+	free(msg);
 	return 0;
 fail:
 	ref_transaction_free(transaction);
 	error("%s", err.buf);
 	strbuf_release(&err);
+	free(msg);
 	return df_conflict ? STORE_REF_ERROR_DF_CONFLICT
 			   : STORE_REF_ERROR_OTHER;
 }
@@ -659,7 +661,7 @@
 
 		if ((recurse_submodules != RECURSE_SUBMODULES_OFF) &&
 		    (recurse_submodules != RECURSE_SUBMODULES_ON))
-			check_for_new_submodule_commits(ref->new_oid.hash);
+			check_for_new_submodule_commits(&ref->new_oid);
 		r = s_update_ref(msg, ref, 0);
 		format_display(display, r ? '!' : '*', what,
 			       r ? _("unable to update local ref") : NULL,
@@ -675,7 +677,7 @@
 		strbuf_add_unique_abbrev(&quickref, ref->new_oid.hash, DEFAULT_ABBREV);
 		if ((recurse_submodules != RECURSE_SUBMODULES_OFF) &&
 		    (recurse_submodules != RECURSE_SUBMODULES_ON))
-			check_for_new_submodule_commits(ref->new_oid.hash);
+			check_for_new_submodule_commits(&ref->new_oid);
 		r = s_update_ref("fast-forward", ref, 1);
 		format_display(display, r ? '!' : ' ', quickref.buf,
 			       r ? _("unable to update local ref") : NULL,
@@ -690,7 +692,7 @@
 		strbuf_add_unique_abbrev(&quickref, ref->new_oid.hash, DEFAULT_ABBREV);
 		if ((recurse_submodules != RECURSE_SUBMODULES_OFF) &&
 		    (recurse_submodules != RECURSE_SUBMODULES_ON))
-			check_for_new_submodule_commits(ref->new_oid.hash);
+			check_for_new_submodule_commits(&ref->new_oid);
 		r = s_update_ref("forced-update", ref, 1);
 		format_display(display, r ? '!' : '+', quickref.buf,
 			       r ? _("unable to update local ref") : _("forced update"),
diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c
index df41fa0..eca365b 100644
--- a/builtin/for-each-ref.c
+++ b/builtin/for-each-ref.c
@@ -8,8 +8,8 @@
 static char const * const for_each_ref_usage[] = {
 	N_("git for-each-ref [<options>] [<pattern>]"),
 	N_("git for-each-ref [--points-at <object>]"),
-	N_("git for-each-ref [(--merged | --no-merged) [<object>]]"),
-	N_("git for-each-ref [--contains [<object>]]"),
+	N_("git for-each-ref [(--merged | --no-merged) [<commit>]]"),
+	N_("git for-each-ref [--contains [<commit>]] [--no-contains [<commit>]]"),
 	NULL
 };
 
@@ -43,6 +43,7 @@
 		OPT_MERGED(&filter, N_("print only refs that are merged")),
 		OPT_NO_MERGED(&filter, N_("print only refs that are not merged")),
 		OPT_CONTAINS(&filter.with_commit, N_("print only refs which contain the commit")),
+		OPT_NO_CONTAINS(&filter.no_commit, N_("print only refs which don't contain the commit")),
 		OPT_BOOL(0, "ignore-case", &icase, N_("sorting and filtering are case insensitive")),
 		OPT_END(),
 	};
diff --git a/builtin/gc.c b/builtin/gc.c
index c2c61a5..91f7696 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -135,8 +135,6 @@
 	 * distributed, we can check only one and get a reasonable
 	 * estimate.
 	 */
-	char path[PATH_MAX];
-	const char *objdir = get_object_directory();
 	DIR *dir;
 	struct dirent *ent;
 	int auto_threshold;
@@ -146,11 +144,7 @@
 	if (gc_auto_threshold <= 0)
 		return 0;
 
-	if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
-		warning(_("insanely long object directory %.*s"), 50, objdir);
-		return 0;
-	}
-	dir = opendir(path);
+	dir = opendir(git_path("objects/17"));
 	if (!dir)
 		return 0;
 
@@ -238,7 +232,7 @@
 static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 {
 	static struct lock_file lock;
-	char my_host[128];
+	char my_host[HOST_NAME_MAX + 1];
 	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
 	uintmax_t pid;
@@ -250,15 +244,19 @@
 		/* already locked */
 		return NULL;
 
-	if (gethostname(my_host, sizeof(my_host)))
+	if (xgethostname(my_host, sizeof(my_host)))
 		xsnprintf(my_host, sizeof(my_host), "unknown");
 
 	pidfile_path = git_pathdup("gc.pid");
 	fd = hold_lock_file_for_update(&lock, pidfile_path,
 				       LOCK_DIE_ON_ERROR);
 	if (!force) {
-		static char locking_host[128];
+		static char locking_host[HOST_NAME_MAX + 1];
+		static char *scan_fmt;
 		int should_exit;
+
+		if (!scan_fmt)
+			scan_fmt = xstrfmt("%s %%%dc", "%"SCNuMAX, HOST_NAME_MAX);
 		fp = fopen(pidfile_path, "r");
 		memset(locking_host, 0, sizeof(locking_host));
 		should_exit =
@@ -274,7 +272,7 @@
 			 * running.
 			 */
 			time(NULL) - st.st_mtime <= 12 * 3600 &&
-			fscanf(fp, "%"SCNuMAX" %127c", &pid, locking_host) == 2 &&
+			fscanf(fp, scan_fmt, &pid, locking_host) == 2 &&
 			/* be gentle to concurrent "gc" on remote hosts */
 			(strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
 		if (fp != NULL)
diff --git a/builtin/grep.c b/builtin/grep.c
index 3f3efa9..3ffb5b4 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -310,10 +310,7 @@
 {
 	struct strbuf pathbuf = STRBUF_INIT;
 
-	if (opt->relative && opt->prefix_length) {
-		quote_path_relative(filename + tree_name_len, opt->prefix, &pathbuf);
-		strbuf_insert(&pathbuf, 0, filename, tree_name_len);
-	} else if (super_prefix) {
+	if (super_prefix) {
 		strbuf_add(&pathbuf, filename, tree_name_len);
 		strbuf_addstr(&pathbuf, super_prefix);
 		strbuf_addstr(&pathbuf, filename + tree_name_len);
@@ -321,6 +318,13 @@
 		strbuf_addstr(&pathbuf, filename);
 	}
 
+	if (opt->relative && opt->prefix_length) {
+		char *name = strbuf_detach(&pathbuf, NULL);
+		quote_path_relative(name + tree_name_len, opt->prefix, &pathbuf);
+		strbuf_insert(&pathbuf, 0, name, tree_name_len);
+		free(name);
+	}
+
 #ifndef NO_PTHREADS
 	if (num_threads) {
 		add_work(opt, GREP_SOURCE_SHA1, pathbuf.buf, path, oid);
@@ -345,12 +349,14 @@
 {
 	struct strbuf buf = STRBUF_INIT;
 
+	if (super_prefix)
+		strbuf_addstr(&buf, super_prefix);
+	strbuf_addstr(&buf, filename);
+
 	if (opt->relative && opt->prefix_length) {
-		quote_path_relative(filename, opt->prefix, &buf);
-	} else {
-		if (super_prefix)
-			strbuf_addstr(&buf, super_prefix);
-		strbuf_addstr(&buf, filename);
+		char *name = strbuf_detach(&buf, NULL);
+		quote_path_relative(name, opt->prefix, &buf);
+		free(name);
 	}
 
 #ifndef NO_PTHREADS
@@ -399,13 +405,12 @@
 }
 
 static void compile_submodule_options(const struct grep_opt *opt,
-				      const struct pathspec *pathspec,
+				      const char **argv,
 				      int cached, int untracked,
 				      int opt_exclude, int use_index,
 				      int pattern_type_arg)
 {
 	struct grep_pat *pattern;
-	int i;
 
 	if (recurse_submodules)
 		argv_array_push(&submodule_options, "--recurse-submodules");
@@ -523,9 +528,8 @@
 
 	/* Add Pathspecs */
 	argv_array_push(&submodule_options, "--");
-	for (i = 0; i < pathspec->nr; i++)
-		argv_array_push(&submodule_options,
-				pathspec->items[i].original);
+	for (; *argv; argv++)
+		argv_array_push(&submodule_options, *argv);
 }
 
 /*
@@ -549,6 +553,11 @@
 	prepare_submodule_repo_env(&cp.env_array);
 	argv_array_push(&cp.env_array, GIT_DIR_ENVIRONMENT);
 
+	if (opt->relative && opt->prefix_length)
+		argv_array_pushf(&cp.env_array, "%s=%s",
+				 GIT_TOPLEVEL_PREFIX_ENVIRONMENT,
+				 opt->prefix);
+
 	/* Add super prefix */
 	argv_array_pushf(&cp.args, "--super-prefix=%s%s/",
 			 super_prefix ? super_prefix : "",
@@ -976,7 +985,7 @@
 		OPT_SET_INT(0, "exclude-standard", &opt_exclude,
 			    N_("ignore files specified via '.gitignore'"), 1),
 		OPT_BOOL(0, "recurse-submodules", &recurse_submodules,
-			 N_("recursivley search in each submodule")),
+			 N_("recursively search in each submodule")),
 		OPT_STRING(0, "parent-basename", &parent_basename,
 			   N_("basename"),
 			   N_("prepend parent project's basename to output")),
@@ -1233,7 +1242,7 @@
 
 	if (recurse_submodules) {
 		gitmodules_config();
-		compile_submodule_options(&opt, &pathspec, cached, untracked,
+		compile_submodule_options(&opt, argv + i, cached, untracked,
 					  opt_exclude, use_index,
 					  pattern_type_arg);
 	}
@@ -1290,6 +1299,7 @@
 		hit |= wait_all();
 	if (hit && show_in_pager)
 		run_pager(&opt, prefix);
+	clear_pathspec(&pathspec);
 	free_grep_patterns(&opt);
 	return !hit;
 }
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 88d205f..4ff567d 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -307,14 +307,15 @@
 	if (from_stdin) {
 		input_fd = 0;
 		if (!pack_name) {
-			static char tmp_file[PATH_MAX];
-			output_fd = odb_mkstemp(tmp_file, sizeof(tmp_file),
+			struct strbuf tmp_file = STRBUF_INIT;
+			output_fd = odb_mkstemp(&tmp_file,
 						"pack/tmp_pack_XXXXXX");
-			pack_name = xstrdup(tmp_file);
-		} else
+			pack_name = strbuf_detach(&tmp_file, NULL);
+		} else {
 			output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
-		if (output_fd < 0)
-			die_errno(_("unable to create '%s'"), pack_name);
+			if (output_fd < 0)
+				die_errno(_("unable to create '%s'"), pack_name);
+		}
 		nothread_data.pack_fd = output_fd;
 	} else {
 		input_fd = open(pack_name, O_RDONLY);
@@ -809,6 +810,8 @@
 		unsigned long has_size;
 		read_lock();
 		has_type = sha1_object_info(sha1, &has_size);
+		if (has_type < 0)
+			die(_("cannot read existing object info %s"), sha1_to_hex(sha1));
 		if (has_type != type || has_size != size)
 			die(_("SHA1 COLLISION FOUND WITH %s !"), sha1_to_hex(sha1));
 		has_data = read_sha1_file(sha1, &has_type, &has_size);
@@ -1442,10 +1445,11 @@
 	if (!from_stdin) {
 		printf("%s\n", sha1_to_hex(sha1));
 	} else {
-		char buf[48];
-		int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
-				   report, sha1_to_hex(sha1));
-		write_or_die(1, buf, len);
+		struct strbuf buf = STRBUF_INIT;
+
+		strbuf_addf(&buf, "%s\t%s\n", report, sha1_to_hex(sha1));
+		write_or_die(1, buf.buf, buf.len);
+		strbuf_release(&buf);
 
 		/*
 		 * Let's just mimic git-unpack-objects here and write
diff --git a/builtin/log.c b/builtin/log.c
index 670229c..b3b10cc 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -52,6 +52,11 @@
 	struct string_list args;
 };
 
+static int auto_decoration_style(void)
+{
+	return (isatty(1) || pager_in_use()) ? DECORATE_SHORT_REFS : 0;
+}
+
 static int parse_decoration_style(const char *var, const char *value)
 {
 	switch (git_config_maybe_bool(var, value)) {
@@ -67,7 +72,7 @@
 	else if (!strcmp(value, "short"))
 		return DECORATE_SHORT_REFS;
 	else if (!strcmp(value, "auto"))
-		return (isatty(1) || pager_in_use()) ? DECORATE_SHORT_REFS : 0;
+		return auto_decoration_style();
 	return -1;
 }
 
@@ -405,6 +410,8 @@
 		if (decoration_style < 0)
 			decoration_style = 0; /* maybe warn? */
 		return 0;
+	} else {
+		decoration_style = auto_decoration_style();
 	}
 	if (!strcmp(var, "log.showroot")) {
 		default_show_root = git_config_bool(var, value);
diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index 1c0f057..a6c70db 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -15,6 +15,7 @@
 #include "string-list.h"
 #include "pathspec.h"
 #include "run-command.h"
+#include "submodule.h"
 
 static int abbrev;
 static int show_deleted;
@@ -30,7 +31,7 @@
 static int debug_mode;
 static int show_eol;
 static int recurse_submodules;
-static struct argv_array submodules_options = ARGV_ARRAY_INIT;
+static struct argv_array submodule_options = ARGV_ARRAY_INIT;
 
 static const char *prefix;
 static const char *super_prefix;
@@ -172,20 +173,27 @@
 /*
  * Compile an argv_array with all of the options supported by --recurse_submodules
  */
-static void compile_submodule_options(const struct dir_struct *dir, int show_tag)
+static void compile_submodule_options(const char **argv,
+				      const struct dir_struct *dir,
+				      int show_tag)
 {
 	if (line_terminator == '\0')
-		argv_array_push(&submodules_options, "-z");
+		argv_array_push(&submodule_options, "-z");
 	if (show_tag)
-		argv_array_push(&submodules_options, "-t");
+		argv_array_push(&submodule_options, "-t");
 	if (show_valid_bit)
-		argv_array_push(&submodules_options, "-v");
+		argv_array_push(&submodule_options, "-v");
 	if (show_cached)
-		argv_array_push(&submodules_options, "--cached");
+		argv_array_push(&submodule_options, "--cached");
 	if (show_eol)
-		argv_array_push(&submodules_options, "--eol");
+		argv_array_push(&submodule_options, "--eol");
 	if (debug_mode)
-		argv_array_push(&submodules_options, "--debug");
+		argv_array_push(&submodule_options, "--debug");
+
+	/* Add Pathspecs */
+	argv_array_push(&submodule_options, "--");
+	for (; *argv; argv++)
+		argv_array_push(&submodule_options, *argv);
 }
 
 /**
@@ -195,8 +203,15 @@
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 	int status;
-	int i;
+	char *dir;
 
+	prepare_submodule_repo_env(&cp.env_array);
+	argv_array_push(&cp.env_array, GIT_DIR_ENVIRONMENT);
+
+	if (prefix_len)
+		argv_array_pushf(&cp.env_array, "%s=%s",
+				 GIT_TOPLEVEL_PREFIX_ENVIRONMENT,
+				 prefix);
 	argv_array_pushf(&cp.args, "--super-prefix=%s%s/",
 			 super_prefix ? super_prefix : "",
 			 ce->name);
@@ -204,20 +219,13 @@
 	argv_array_push(&cp.args, "--recurse-submodules");
 
 	/* add supported options */
-	argv_array_pushv(&cp.args, submodules_options.argv);
-
-	/*
-	 * Pass in the original pathspec args.  The submodule will be
-	 * responsible for prepending the 'submodule_prefix' prior to comparing
-	 * against the pathspec for matches.
-	 */
-	argv_array_push(&cp.args, "--");
-	for (i = 0; i < pathspec.nr; i++)
-		argv_array_push(&cp.args, pathspec.items[i].original);
+	argv_array_pushv(&cp.args, submodule_options.argv);
 
 	cp.git_cmd = 1;
-	cp.dir = ce->name;
+	dir = mkpathdup("%s/%s", get_git_work_tree(), ce->name);
+	cp.dir = dir;
 	status = run_command(&cp);
+	free(dir);
 	if (status)
 		exit(status);
 }
@@ -604,7 +612,7 @@
 		setup_work_tree();
 
 	if (recurse_submodules)
-		compile_submodule_options(&dir, show_tag);
+		compile_submodule_options(argv, &dir, show_tag);
 
 	if (recurse_submodules &&
 	    (show_stage || show_deleted || show_others || show_unmerged ||
diff --git a/builtin/ls-remote.c b/builtin/ls-remote.c
index 66cdd45..b2d7d5c 100644
--- a/builtin/ls-remote.c
+++ b/builtin/ls-remote.c
@@ -17,17 +17,19 @@
 static int tail_match(const char **pattern, const char *path)
 {
 	const char *p;
-	char pathbuf[PATH_MAX];
+	char *pathbuf;
 
 	if (!pattern)
 		return 1; /* no restriction */
 
-	if (snprintf(pathbuf, sizeof(pathbuf), "/%s", path) > sizeof(pathbuf))
-		return error("insanely long ref %.*s...", 20, path);
+	pathbuf = xstrfmt("/%s", path);
 	while ((p = *(pattern++)) != NULL) {
-		if (!wildmatch(p, pathbuf, 0, NULL))
+		if (!wildmatch(p, pathbuf, 0, NULL)) {
+			free(pathbuf);
 			return 1;
+		}
 	}
+	free(pathbuf);
 	return 0;
 }
 
diff --git a/builtin/merge-index.c b/builtin/merge-index.c
index 2d1b6db..c99443b 100644
--- a/builtin/merge-index.c
+++ b/builtin/merge-index.c
@@ -9,7 +9,7 @@
 {
 	int found;
 	const char *arguments[] = { pgm, "", "", "", path, "", "", "", NULL };
-	char hexbuf[4][GIT_SHA1_HEXSZ + 1];
+	char hexbuf[4][GIT_MAX_HEXSZ + 1];
 	char ownbuf[4][60];
 
 	if (pos >= active_nr)
diff --git a/builtin/merge.c b/builtin/merge.c
index 7554b8d..703827f 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -44,7 +44,6 @@
 
 static const char * const builtin_merge_usage[] = {
 	N_("git merge [<options>] [<commit>...]"),
-	N_("git merge [<options>] <msg> HEAD <commit>"),
 	N_("git merge --abort"),
 	N_("git merge --continue"),
 	NULL
@@ -634,9 +633,10 @@
 
 static int try_merge_strategy(const char *strategy, struct commit_list *common,
 			      struct commit_list *remoteheads,
-			      struct commit *head, const char *head_arg)
+			      struct commit *head)
 {
 	static struct lock_file lock;
+	const char *head_arg = "HEAD";
 
 	hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
 	refresh_cache(REFRESH_QUIET);
@@ -853,24 +853,6 @@
 	return 1;
 }
 
-static struct commit *is_old_style_invocation(int argc, const char **argv,
-					      const struct object_id *head)
-{
-	struct commit *second_token = NULL;
-	if (argc > 2) {
-		struct object_id second_oid;
-
-		if (get_oid(argv[1], &second_oid))
-			return NULL;
-		second_token = lookup_commit_reference_gently(second_oid.hash, 0);
-		if (!second_token)
-			die(_("'%s' is not a commit"), argv[1]);
-		if (oidcmp(&second_token->object.oid, head))
-			return NULL;
-	}
-	return second_token;
-}
-
 static int evaluate_result(void)
 {
 	int cnt = 0;
@@ -1120,7 +1102,6 @@
 	struct object_id result_tree, stash, head_oid;
 	struct commit *head_commit;
 	struct strbuf buf = STRBUF_INIT;
-	const char *head_arg;
 	int i, ret = 0, head_subsumed;
 	int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
 	struct commit_list *common = NULL;
@@ -1260,34 +1241,12 @@
 	}
 
 	/*
-	 * This could be traditional "merge <msg> HEAD <commit>..."  and
-	 * the way we can tell it is to see if the second token is HEAD,
-	 * but some people might have misused the interface and used a
-	 * commit-ish that is the same as HEAD there instead.
-	 * Traditional format never would have "-m" so it is an
-	 * additional safety measure to check for it.
+	 * All the rest are the commits being merged; prepare
+	 * the standard merge summary message to be appended
+	 * to the given message.
 	 */
-	if (!have_message &&
-	    is_old_style_invocation(argc, argv, &head_commit->object.oid)) {
-		warning("old-style 'git merge <msg> HEAD <commit>' is deprecated.");
-		strbuf_addstr(&merge_msg, argv[0]);
-		head_arg = argv[1];
-		argv += 2;
-		argc -= 2;
-		remoteheads = collect_parents(head_commit, &head_subsumed,
-					      argc, argv, NULL);
-	} else {
-		/* We are invoked directly as the first-class UI. */
-		head_arg = "HEAD";
-
-		/*
-		 * All the rest are the commits being merged; prepare
-		 * the standard merge summary message to be appended
-		 * to the given message.
-		 */
-		remoteheads = collect_parents(head_commit, &head_subsumed,
-					      argc, argv, &merge_msg);
-	}
+	remoteheads = collect_parents(head_commit, &head_subsumed,
+				      argc, argv, &merge_msg);
 
 	if (!head_commit || !argc)
 		usage_with_options(builtin_merge_usage,
@@ -1296,7 +1255,7 @@
 	if (verify_signatures) {
 		for (p = remoteheads; p; p = p->next) {
 			struct commit *commit = p->item;
-			char hex[GIT_SHA1_HEXSZ + 1];
+			char hex[GIT_MAX_HEXSZ + 1];
 			struct signature_check signature_check;
 			memset(&signature_check, 0, sizeof(signature_check));
 
@@ -1513,7 +1472,7 @@
 
 		ret = try_merge_strategy(use_strategies[i]->name,
 					 common, remoteheads,
-					 head_commit, head_arg);
+					 head_commit);
 		if (!option_commit && !ret) {
 			merge_was_ok = 1;
 			/*
@@ -1583,7 +1542,7 @@
 		printf(_("Using the %s to prepare resolving by hand.\n"),
 			best_strategy);
 		try_merge_strategy(best_strategy, common, remoteheads,
-				   head_commit, head_arg);
+				   head_commit);
 	}
 
 	if (squash)
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index 8bdc3ea..92a5d8a 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -238,10 +238,9 @@
 	return NULL;
 }
 
-/* returns a static buffer */
-static const char *get_rev_name(const struct object *o)
+/* may return a constant string or use "buf" as scratch space */
+static const char *get_rev_name(const struct object *o, struct strbuf *buf)
 {
-	static char buffer[1024];
 	struct rev_name *n;
 	struct commit *c;
 
@@ -258,10 +257,9 @@
 		int len = strlen(n->tip_name);
 		if (len > 2 && !strcmp(n->tip_name + len - 2, "^0"))
 			len -= 2;
-		snprintf(buffer, sizeof(buffer), "%.*s~%d", len, n->tip_name,
-				n->generation);
-
-		return buffer;
+		strbuf_reset(buf);
+		strbuf_addf(buf, "%.*s~%d", len, n->tip_name, n->generation);
+		return buf->buf;
 	}
 }
 
@@ -271,10 +269,11 @@
 {
 	const char *name;
 	const struct object_id *oid = &obj->oid;
+	struct strbuf buf = STRBUF_INIT;
 
 	if (!name_only)
 		printf("%s ", caller_name ? caller_name : oid_to_hex(oid));
-	name = get_rev_name(obj);
+	name = get_rev_name(obj, &buf);
 	if (name)
 		printf("%s\n", name);
 	else if (allow_undefined)
@@ -283,6 +282,7 @@
 		printf("%s\n", find_unique_abbrev(oid->hash, DEFAULT_ABBREV));
 	else
 		die("cannot describe '%s'", oid_to_hex(oid));
+	strbuf_release(&buf);
 }
 
 static char const * const name_rev_usage[] = {
@@ -294,6 +294,7 @@
 
 static void name_rev_line(char *p, struct name_ref_data *data)
 {
+	struct strbuf buf = STRBUF_INIT;
 	int forty = 0;
 	char *p_start;
 	for (p_start = p; *p; p++) {
@@ -314,7 +315,7 @@
 				struct object *o =
 					lookup_object(sha1);
 				if (o)
-					name = get_rev_name(o);
+					name = get_rev_name(o, &buf);
 			}
 			*(p+1) = c;
 
@@ -332,6 +333,8 @@
 	/* flush */
 	if (p_start != p)
 		fwrite(p_start, p - p_start, 1, stdout);
+
+	strbuf_release(&buf);
 }
 
 int cmd_name_rev(int argc, const char **argv, const char *prefix)
diff --git a/builtin/notes.c b/builtin/notes.c
index 0513f74..7b89147 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -554,7 +554,7 @@
 	struct notes_tree *t;
 	unsigned char object[20], new_note[20];
 	const unsigned char *note;
-	char logmsg[100];
+	char *logmsg;
 	const char * const *usage;
 	struct note_data d = { 0, 0, NULL, STRBUF_INIT };
 	struct option options[] = {
@@ -618,17 +618,16 @@
 		write_note_data(&d, new_note);
 		if (add_note(t, object, new_note, combine_notes_overwrite))
 			die("BUG: combine_notes_overwrite failed");
-		snprintf(logmsg, sizeof(logmsg), "Notes added by 'git notes %s'",
-			argv[0]);
+		logmsg = xstrfmt("Notes added by 'git notes %s'", argv[0]);
 	} else {
 		fprintf(stderr, _("Removing note for object %s\n"),
 			sha1_to_hex(object));
 		remove_note(t, object);
-		snprintf(logmsg, sizeof(logmsg), "Notes removed by 'git notes %s'",
-			argv[0]);
+		logmsg = xstrfmt("Notes removed by 'git notes %s'", argv[0]);
 	}
 	commit_notes(t, logmsg);
 
+	free(logmsg);
 	free_note_data(&d);
 	free_notes(t);
 	return 0;
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 84af7c2..0fe35d1 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -2672,16 +2672,16 @@
  *
  * This is filled by get_object_list.
  */
-static struct sha1_array recent_objects;
+static struct oid_array recent_objects;
 
-static int loosened_object_can_be_discarded(const unsigned char *sha1,
+static int loosened_object_can_be_discarded(const struct object_id *oid,
 					    unsigned long mtime)
 {
 	if (!unpack_unreachable_expiration)
 		return 0;
 	if (mtime > unpack_unreachable_expiration)
 		return 0;
-	if (sha1_array_lookup(&recent_objects, sha1) >= 0)
+	if (oid_array_lookup(&recent_objects, oid) >= 0)
 		return 0;
 	return 1;
 }
@@ -2690,7 +2690,7 @@
 {
 	struct packed_git *p;
 	uint32_t i;
-	const unsigned char *sha1;
+	struct object_id oid;
 
 	for (p = packed_git; p; p = p->next) {
 		if (!p->pack_local || p->pack_keep)
@@ -2700,11 +2700,11 @@
 			die("cannot open pack index");
 
 		for (i = 0; i < p->num_objects; i++) {
-			sha1 = nth_packed_object_sha1(p, i);
-			if (!packlist_find(&to_pack, sha1, NULL) &&
-			    !has_sha1_pack_kept_or_nonlocal(sha1) &&
-			    !loosened_object_can_be_discarded(sha1, p->mtime))
-				if (force_object_loose(sha1, p->mtime))
+			nth_packed_object_oid(&oid, p, i);
+			if (!packlist_find(&to_pack, oid.hash, NULL) &&
+			    !has_sha1_pack_kept_or_nonlocal(oid.hash) &&
+			    !loosened_object_can_be_discarded(&oid, p->mtime))
+				if (force_object_loose(oid.hash, p->mtime))
 					die("unable to force loose object");
 		}
 	}
@@ -2743,12 +2743,12 @@
 				 const char *name,
 				 void *data)
 {
-	sha1_array_append(&recent_objects, obj->oid.hash);
+	oid_array_append(&recent_objects, &obj->oid);
 }
 
 static void record_recent_commit(struct commit *commit, void *data)
 {
-	sha1_array_append(&recent_objects, commit->object.oid.hash);
+	oid_array_append(&recent_objects, &commit->object.oid);
 }
 
 static void get_object_list(int ac, const char **av)
@@ -2816,7 +2816,7 @@
 	if (unpack_unreachable)
 		loosen_unused_packed_objects(&revs);
 
-	sha1_array_clear(&recent_objects);
+	oid_array_clear(&recent_objects);
 }
 
 static int option_parse_index_version(const struct option *opt,
diff --git a/builtin/pack-refs.c b/builtin/pack-refs.c
index 39f9a55..b106a39 100644
--- a/builtin/pack-refs.c
+++ b/builtin/pack-refs.c
@@ -17,5 +17,5 @@
 	};
 	if (parse_options(argc, argv, prefix, opts, pack_refs_usage, 0))
 		usage_with_options(pack_refs_usage, opts);
-	return pack_refs(flags);
+	return refs_pack_refs(get_main_ref_store(), flags);
 }
diff --git a/builtin/patch-id.c b/builtin/patch-id.c
index a84d000..81552e0 100644
--- a/builtin/patch-id.c
+++ b/builtin/patch-id.c
@@ -55,7 +55,7 @@
 
 static void flush_one_hunk(struct object_id *result, git_SHA_CTX *ctx)
 {
-	unsigned char hash[GIT_SHA1_RAWSZ];
+	unsigned char hash[GIT_MAX_RAWSZ];
 	unsigned short carry = 0;
 	int i;
 
diff --git a/builtin/pull.c b/builtin/pull.c
index 3ecb881..dd1a4a9 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -330,21 +330,21 @@
  * Appends merge candidates from FETCH_HEAD that are not marked not-for-merge
  * into merge_heads.
  */
-static void get_merge_heads(struct sha1_array *merge_heads)
+static void get_merge_heads(struct oid_array *merge_heads)
 {
-	const char *filename = git_path("FETCH_HEAD");
+	const char *filename = git_path_fetch_head();
 	FILE *fp;
 	struct strbuf sb = STRBUF_INIT;
-	unsigned char sha1[GIT_SHA1_RAWSZ];
+	struct object_id oid;
 
 	if (!(fp = fopen(filename, "r")))
 		die_errno(_("could not open '%s' for reading"), filename);
 	while (strbuf_getline_lf(&sb, fp) != EOF) {
-		if (get_sha1_hex(sb.buf, sha1))
+		if (get_oid_hex(sb.buf, &oid))
 			continue;  /* invalid line: does not start with SHA1 */
 		if (starts_with(sb.buf + GIT_SHA1_HEXSZ, "\tnot-for-merge\t"))
 			continue;  /* ref is not-for-merge */
-		sha1_array_append(merge_heads, sha1);
+		oid_array_append(merge_heads, &oid);
 	}
 	fclose(fp);
 	strbuf_release(&sb);
@@ -514,8 +514,8 @@
 /**
  * "Pulls into void" by branching off merge_head.
  */
-static int pull_into_void(const unsigned char *merge_head,
-		const unsigned char *curr_head)
+static int pull_into_void(const struct object_id *merge_head,
+		const struct object_id *curr_head)
 {
 	/*
 	 * Two-way merge: we treat the index as based on an empty tree,
@@ -523,10 +523,10 @@
 	 * index/worktree changes that the user already made on the unborn
 	 * branch.
 	 */
-	if (checkout_fast_forward(EMPTY_TREE_SHA1_BIN, merge_head, 0))
+	if (checkout_fast_forward(EMPTY_TREE_SHA1_BIN, merge_head->hash, 0))
 		return 1;
 
-	if (update_ref("initial pull", "HEAD", merge_head, curr_head, 0, UPDATE_REFS_DIE_ON_ERR))
+	if (update_ref("initial pull", "HEAD", merge_head->hash, curr_head->hash, 0, UPDATE_REFS_DIE_ON_ERR))
 		return 1;
 
 	return 0;
@@ -647,7 +647,7 @@
  * current branch forked from its remote tracking branch. Returns 0 on success,
  * -1 on failure.
  */
-static int get_rebase_fork_point(unsigned char *fork_point, const char *repo,
+static int get_rebase_fork_point(struct object_id *fork_point, const char *repo,
 		const char *refspec)
 {
 	int ret;
@@ -678,7 +678,7 @@
 	if (ret)
 		goto cleanup;
 
-	ret = get_sha1_hex(sb.buf, fork_point);
+	ret = get_oid_hex(sb.buf, fork_point);
 	if (ret)
 		goto cleanup;
 
@@ -691,24 +691,24 @@
  * Sets merge_base to the octopus merge base of curr_head, merge_head and
  * fork_point. Returns 0 if a merge base is found, 1 otherwise.
  */
-static int get_octopus_merge_base(unsigned char *merge_base,
-		const unsigned char *curr_head,
-		const unsigned char *merge_head,
-		const unsigned char *fork_point)
+static int get_octopus_merge_base(struct object_id *merge_base,
+		const struct object_id *curr_head,
+		const struct object_id *merge_head,
+		const struct object_id *fork_point)
 {
 	struct commit_list *revs = NULL, *result;
 
-	commit_list_insert(lookup_commit_reference(curr_head), &revs);
-	commit_list_insert(lookup_commit_reference(merge_head), &revs);
-	if (!is_null_sha1(fork_point))
-		commit_list_insert(lookup_commit_reference(fork_point), &revs);
+	commit_list_insert(lookup_commit_reference(curr_head->hash), &revs);
+	commit_list_insert(lookup_commit_reference(merge_head->hash), &revs);
+	if (!is_null_oid(fork_point))
+		commit_list_insert(lookup_commit_reference(fork_point->hash), &revs);
 
 	result = reduce_heads(get_octopus_merge_bases(revs));
 	free_commit_list(revs);
 	if (!result)
 		return 1;
 
-	hashcpy(merge_base, result->item->object.oid.hash);
+	oidcpy(merge_base, &result->item->object.oid);
 	return 0;
 }
 
@@ -717,16 +717,16 @@
  * fork point calculated by get_rebase_fork_point(), runs git-rebase with the
  * appropriate arguments and returns its exit status.
  */
-static int run_rebase(const unsigned char *curr_head,
-		const unsigned char *merge_head,
-		const unsigned char *fork_point)
+static int run_rebase(const struct object_id *curr_head,
+		const struct object_id *merge_head,
+		const struct object_id *fork_point)
 {
 	int ret;
-	unsigned char oct_merge_base[GIT_SHA1_RAWSZ];
+	struct object_id oct_merge_base;
 	struct argv_array args = ARGV_ARRAY_INIT;
 
-	if (!get_octopus_merge_base(oct_merge_base, curr_head, merge_head, fork_point))
-		if (!is_null_sha1(fork_point) && !hashcmp(oct_merge_base, fork_point))
+	if (!get_octopus_merge_base(&oct_merge_base, curr_head, merge_head, fork_point))
+		if (!is_null_oid(fork_point) && !oidcmp(&oct_merge_base, fork_point))
 			fork_point = NULL;
 
 	argv_array_push(&args, "rebase");
@@ -754,12 +754,12 @@
 		warning(_("ignoring --verify-signatures for rebase"));
 
 	argv_array_push(&args, "--onto");
-	argv_array_push(&args, sha1_to_hex(merge_head));
+	argv_array_push(&args, oid_to_hex(merge_head));
 
-	if (fork_point && !is_null_sha1(fork_point))
-		argv_array_push(&args, sha1_to_hex(fork_point));
+	if (fork_point && !is_null_oid(fork_point))
+		argv_array_push(&args, oid_to_hex(fork_point));
 	else
-		argv_array_push(&args, sha1_to_hex(merge_head));
+		argv_array_push(&args, oid_to_hex(merge_head));
 
 	ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
 	argv_array_clear(&args);
@@ -769,9 +769,9 @@
 int cmd_pull(int argc, const char **argv, const char *prefix)
 {
 	const char *repo, **refspecs;
-	struct sha1_array merge_heads = SHA1_ARRAY_INIT;
-	unsigned char orig_head[GIT_SHA1_RAWSZ], curr_head[GIT_SHA1_RAWSZ];
-	unsigned char rebase_fork_point[GIT_SHA1_RAWSZ];
+	struct oid_array merge_heads = OID_ARRAY_INIT;
+	struct object_id orig_head, curr_head;
+	struct object_id rebase_fork_point;
 
 	if (!getenv("GIT_REFLOG_ACTION"))
 		set_reflog_message(argc, argv);
@@ -791,11 +791,11 @@
 	if (read_cache_unmerged())
 		die_resolve_conflict("pull");
 
-	if (file_exists(git_path("MERGE_HEAD")))
+	if (file_exists(git_path_merge_head()))
 		die_conclude_merge();
 
-	if (get_sha1("HEAD", orig_head))
-		hashclr(orig_head);
+	if (get_oid("HEAD", &orig_head))
+		oidclr(&orig_head);
 
 	if (!opt_rebase && opt_autostash != -1)
 		die(_("--[no-]autostash option is only valid with --rebase."));
@@ -805,15 +805,15 @@
 		if (opt_autostash != -1)
 			autostash = opt_autostash;
 
-		if (is_null_sha1(orig_head) && !is_cache_unborn())
+		if (is_null_oid(&orig_head) && !is_cache_unborn())
 			die(_("Updating an unborn branch with changes added to the index."));
 
 		if (!autostash)
 			require_clean_work_tree(N_("pull with rebase"),
 				_("please commit or stash them."), 1, 0);
 
-		if (get_rebase_fork_point(rebase_fork_point, repo, *refspecs))
-			hashclr(rebase_fork_point);
+		if (get_rebase_fork_point(&rebase_fork_point, repo, *refspecs))
+			oidclr(&rebase_fork_point);
 	}
 
 	if (run_fetch(repo, refspecs))
@@ -822,11 +822,11 @@
 	if (opt_dry_run)
 		return 0;
 
-	if (get_sha1("HEAD", curr_head))
-		hashclr(curr_head);
+	if (get_oid("HEAD", &curr_head))
+		oidclr(&curr_head);
 
-	if (!is_null_sha1(orig_head) && !is_null_sha1(curr_head) &&
-			hashcmp(orig_head, curr_head)) {
+	if (!is_null_oid(&orig_head) && !is_null_oid(&curr_head) &&
+			oidcmp(&orig_head, &curr_head)) {
 		/*
 		 * The fetch involved updating the current branch.
 		 *
@@ -837,15 +837,15 @@
 
 		warning(_("fetch updated the current branch head.\n"
 			"fast-forwarding your working tree from\n"
-			"commit %s."), sha1_to_hex(orig_head));
+			"commit %s."), oid_to_hex(&orig_head));
 
-		if (checkout_fast_forward(orig_head, curr_head, 0))
+		if (checkout_fast_forward(orig_head.hash, curr_head.hash, 0))
 			die(_("Cannot fast-forward your working tree.\n"
 				"After making sure that you saved anything precious from\n"
 				"$ git diff %s\n"
 				"output, run\n"
 				"$ git reset --hard\n"
-				"to recover."), sha1_to_hex(orig_head));
+				"to recover."), oid_to_hex(&orig_head));
 	}
 
 	get_merge_heads(&merge_heads);
@@ -853,10 +853,10 @@
 	if (!merge_heads.nr)
 		die_no_merge_candidates(repo, refspecs);
 
-	if (is_null_sha1(orig_head)) {
+	if (is_null_oid(&orig_head)) {
 		if (merge_heads.nr > 1)
 			die(_("Cannot merge multiple branches into empty head."));
-		return pull_into_void(*merge_heads.sha1, curr_head);
+		return pull_into_void(merge_heads.oid, &curr_head);
 	}
 	if (opt_rebase && merge_heads.nr > 1)
 		die(_("Cannot rebase onto multiple branches."));
@@ -865,15 +865,15 @@
 		struct commit_list *list = NULL;
 		struct commit *merge_head, *head;
 
-		head = lookup_commit_reference(orig_head);
+		head = lookup_commit_reference(orig_head.hash);
 		commit_list_insert(head, &list);
-		merge_head = lookup_commit_reference(merge_heads.sha1[0]);
+		merge_head = lookup_commit_reference(merge_heads.oid[0].hash);
 		if (is_descendant_of(merge_head, list)) {
 			/* we can fast-forward this without invoking rebase */
 			opt_ff = "--ff-only";
 			return run_merge();
 		}
-		return run_rebase(curr_head, *merge_heads.sha1, rebase_fork_point);
+		return run_rebase(&curr_head, merge_heads.oid, &rebase_fork_point);
 	} else {
 		return run_merge();
 	}
diff --git a/builtin/push.c b/builtin/push.c
index 5c22e9f..a597759 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -510,8 +510,8 @@
 	int push_cert = -1;
 	int rc;
 	const char *repo = NULL;	/* default repository */
-	static struct string_list push_options = STRING_LIST_INIT_DUP;
-	static struct string_list_item *item;
+	struct string_list push_options = STRING_LIST_INIT_DUP;
+	const struct string_list_item *item;
 
 	struct option options[] = {
 		OPT__VERBOSITY(&verbosity),
@@ -584,6 +584,7 @@
 			die(_("push options must not have new line characters"));
 
 	rc = do_push(repo, flags, &push_options);
+	string_list_clear(&push_options, 0);
 	if (rc == -1)
 		usage_with_options(push_usage, options);
 	else
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index fb2a090..f96834f 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -225,10 +225,10 @@
 	return git_default_config(var, value, cb);
 }
 
-static void show_ref(const char *path, const unsigned char *sha1)
+static void show_ref(const char *path, const struct object_id *oid)
 {
 	if (sent_capabilities) {
-		packet_write_fmt(1, "%s %s\n", sha1_to_hex(sha1), path);
+		packet_write_fmt(1, "%s %s\n", oid_to_hex(oid), path);
 	} else {
 		struct strbuf cap = STRBUF_INIT;
 
@@ -244,7 +244,7 @@
 			strbuf_addstr(&cap, " push-options");
 		strbuf_addf(&cap, " agent=%s", git_user_agent_sanitized());
 		packet_write_fmt(1, "%s %s%c%s\n",
-			     sha1_to_hex(sha1), path, 0, cap.buf);
+			     oid_to_hex(oid), path, 0, cap.buf);
 		strbuf_release(&cap);
 		sent_capabilities = 1;
 	}
@@ -271,7 +271,7 @@
 	} else {
 		oidset_insert(seen, oid);
 	}
-	show_ref(path, oid->hash);
+	show_ref(path, oid);
 	return 0;
 }
 
@@ -284,7 +284,7 @@
 	if (oidset_insert(seen, oid))
 		return;
 
-	show_ref(".have", oid->hash);
+	show_ref(".have", oid);
 }
 
 static void write_head_info(void)
@@ -295,7 +295,7 @@
 	for_each_alternate_ref(show_one_alternate_ref, &seen);
 	oidset_clear(&seen);
 	if (!sent_capabilities)
-		show_ref("capabilities^{}", null_sha1);
+		show_ref("capabilities^{}", &null_oid);
 
 	advertise_shallow_grafts(1);
 
@@ -309,8 +309,8 @@
 	unsigned int skip_update:1,
 		     did_not_exist:1;
 	int index;
-	unsigned char old_sha1[20];
-	unsigned char new_sha1[20];
+	struct object_id old_oid;
+	struct object_id new_oid;
 	char ref_name[FLEX_ARRAY]; /* more */
 };
 
@@ -723,7 +723,7 @@
 		return -1; /* EOF */
 	strbuf_reset(&state->buf);
 	strbuf_addf(&state->buf, "%s %s %s\n",
-		    sha1_to_hex(cmd->old_sha1), sha1_to_hex(cmd->new_sha1),
+		    oid_to_hex(&cmd->old_oid), oid_to_hex(&cmd->new_oid),
 		    cmd->ref_name);
 	state->cmd = cmd->next;
 	if (bufp) {
@@ -764,15 +764,14 @@
 		return 0;
 
 	argv[1] = cmd->ref_name;
-	argv[2] = sha1_to_hex(cmd->old_sha1);
-	argv[3] = sha1_to_hex(cmd->new_sha1);
+	argv[2] = oid_to_hex(&cmd->old_oid);
+	argv[3] = oid_to_hex(&cmd->new_oid);
 	argv[4] = NULL;
 
 	proc.no_stdin = 1;
 	proc.stdout_to_stderr = 1;
 	proc.err = use_sideband ? -1 : 0;
 	proc.argv = argv;
-	proc.env = tmp_objdir_env(tmp_objdir);
 
 	code = start_command(&proc);
 	if (code)
@@ -831,7 +830,7 @@
 static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
 {
 	static struct lock_file shallow_lock;
-	struct sha1_array extra = SHA1_ARRAY_INIT;
+	struct oid_array extra = OID_ARRAY_INIT;
 	struct check_connected_options opt = CHECK_CONNECTED_INIT;
 	uint32_t mask = 1 << (cmd->index % 32);
 	int i;
@@ -842,13 +841,13 @@
 		if (si->used_shallow[i] &&
 		    (si->used_shallow[i][cmd->index / 32] & mask) &&
 		    !delayed_reachability_test(si, i))
-			sha1_array_append(&extra, si->shallow->sha1[i]);
+			oid_array_append(&extra, &si->shallow->oid[i]);
 
 	opt.env = tmp_objdir_env(tmp_objdir);
 	setup_alternate_shallow(&shallow_lock, &opt.shallow_file, &extra);
 	if (check_connected(command_singleton_iterator, cmd, &opt)) {
 		rollback_lock_file(&shallow_lock);
-		sha1_array_clear(&extra);
+		oid_array_clear(&extra);
 		return -1;
 	}
 
@@ -859,10 +858,10 @@
 	 * not lose these new roots..
 	 */
 	for (i = 0; i < extra.nr; i++)
-		register_shallow(extra.sha1[i]);
+		register_shallow(extra.oid[i].hash);
 
 	si->shallow_ref[cmd->index] = 0;
-	sha1_array_clear(&extra);
+	oid_array_clear(&extra);
 	return 0;
 }
 
@@ -988,8 +987,8 @@
 	const char *name = cmd->ref_name;
 	struct strbuf namespaced_name_buf = STRBUF_INIT;
 	const char *namespaced_name, *ret;
-	unsigned char *old_sha1 = cmd->old_sha1;
-	unsigned char *new_sha1 = cmd->new_sha1;
+	struct object_id *old_oid = &cmd->old_oid;
+	struct object_id *new_oid = &cmd->new_oid;
 
 	/* only refs/... are allowed */
 	if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
@@ -1014,20 +1013,20 @@
 				refuse_unconfigured_deny();
 			return "branch is currently checked out";
 		case DENY_UPDATE_INSTEAD:
-			ret = update_worktree(new_sha1);
+			ret = update_worktree(new_oid->hash);
 			if (ret)
 				return ret;
 			break;
 		}
 	}
 
-	if (!is_null_sha1(new_sha1) && !has_sha1_file(new_sha1)) {
+	if (!is_null_oid(new_oid) && !has_object_file(new_oid)) {
 		error("unpack should have generated %s, "
-		      "but I can't find it!", sha1_to_hex(new_sha1));
+		      "but I can't find it!", oid_to_hex(new_oid));
 		return "bad pack";
 	}
 
-	if (!is_null_sha1(old_sha1) && is_null_sha1(new_sha1)) {
+	if (!is_null_oid(old_oid) && is_null_oid(new_oid)) {
 		if (deny_deletes && starts_with(name, "refs/heads/")) {
 			rp_error("denying ref deletion for %s", name);
 			return "deletion prohibited";
@@ -1053,14 +1052,14 @@
 		}
 	}
 
-	if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
-	    !is_null_sha1(old_sha1) &&
+	if (deny_non_fast_forwards && !is_null_oid(new_oid) &&
+	    !is_null_oid(old_oid) &&
 	    starts_with(name, "refs/heads/")) {
 		struct object *old_object, *new_object;
 		struct commit *old_commit, *new_commit;
 
-		old_object = parse_object(old_sha1);
-		new_object = parse_object(new_sha1);
+		old_object = parse_object(old_oid->hash);
+		new_object = parse_object(new_oid->hash);
 
 		if (!old_object || !new_object ||
 		    old_object->type != OBJ_COMMIT ||
@@ -1081,10 +1080,10 @@
 		return "hook declined";
 	}
 
-	if (is_null_sha1(new_sha1)) {
+	if (is_null_oid(new_oid)) {
 		struct strbuf err = STRBUF_INIT;
-		if (!parse_object(old_sha1)) {
-			old_sha1 = NULL;
+		if (!parse_object(old_oid->hash)) {
+			old_oid = NULL;
 			if (ref_exists(name)) {
 				rp_warning("Allowing deletion of corrupt ref.");
 			} else {
@@ -1094,7 +1093,7 @@
 		}
 		if (ref_transaction_delete(transaction,
 					   namespaced_name,
-					   old_sha1,
+					   old_oid->hash,
 					   0, "push", &err)) {
 			rp_error("%s", err.buf);
 			strbuf_release(&err);
@@ -1111,7 +1110,7 @@
 
 		if (ref_transaction_update(transaction,
 					   namespaced_name,
-					   new_sha1, old_sha1,
+					   new_oid->hash, old_oid->hash,
 					   0, "push",
 					   &err)) {
 			rp_error("%s", err.buf);
@@ -1162,7 +1161,7 @@
 	const char *dst_name;
 	struct string_list_item *item;
 	struct command *dst_cmd;
-	unsigned char sha1[GIT_SHA1_RAWSZ];
+	unsigned char sha1[GIT_MAX_RAWSZ];
 	int flag;
 
 	strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
@@ -1187,8 +1186,8 @@
 
 	dst_cmd = (struct command *) item->util;
 
-	if (!hashcmp(cmd->old_sha1, dst_cmd->old_sha1) &&
-	    !hashcmp(cmd->new_sha1, dst_cmd->new_sha1))
+	if (!oidcmp(&cmd->old_oid, &dst_cmd->old_oid) &&
+	    !oidcmp(&cmd->new_oid, &dst_cmd->new_oid))
 		return;
 
 	dst_cmd->skip_update = 1;
@@ -1196,11 +1195,11 @@
 	rp_error("refusing inconsistent update between symref '%s' (%s..%s) and"
 		 " its target '%s' (%s..%s)",
 		 cmd->ref_name,
-		 find_unique_abbrev(cmd->old_sha1, DEFAULT_ABBREV),
-		 find_unique_abbrev(cmd->new_sha1, DEFAULT_ABBREV),
+		 find_unique_abbrev(cmd->old_oid.hash, DEFAULT_ABBREV),
+		 find_unique_abbrev(cmd->new_oid.hash, DEFAULT_ABBREV),
 		 dst_cmd->ref_name,
-		 find_unique_abbrev(dst_cmd->old_sha1, DEFAULT_ABBREV),
-		 find_unique_abbrev(dst_cmd->new_sha1, DEFAULT_ABBREV));
+		 find_unique_abbrev(dst_cmd->old_oid.hash, DEFAULT_ABBREV),
+		 find_unique_abbrev(dst_cmd->new_oid.hash, DEFAULT_ABBREV));
 
 	cmd->error_string = dst_cmd->error_string =
 		"inconsistent aliased update";
@@ -1231,10 +1230,10 @@
 	struct command **cmd_list = cb_data;
 	struct command *cmd = *cmd_list;
 
-	if (!cmd || is_null_sha1(cmd->new_sha1))
+	if (!cmd || is_null_oid(&cmd->new_oid))
 		return -1; /* end of list */
 	*cmd_list = NULL; /* this returns only one */
-	hashcpy(sha1, cmd->new_sha1);
+	hashcpy(sha1, cmd->new_oid.hash);
 	return 0;
 }
 
@@ -1275,8 +1274,8 @@
 		if (shallow_update && data->si->shallow_ref[cmd->index])
 			/* to be checked in update_shallow_ref() */
 			continue;
-		if (!is_null_sha1(cmd->new_sha1) && !cmd->skip_update) {
-			hashcpy(sha1, cmd->new_sha1);
+		if (!is_null_oid(&cmd->new_oid) && !cmd->skip_update) {
+			hashcpy(sha1, cmd->new_oid.hash);
 			*cmd_list = cmd->next;
 			return 0;
 		}
@@ -1303,7 +1302,7 @@
 
 		if (!ref_is_hidden(cmd->ref_name, refname_full.buf))
 			continue;
-		if (is_null_sha1(cmd->new_sha1))
+		if (is_null_oid(&cmd->new_oid))
 			cmd->error_string = "deny deleting a hidden ref";
 		else
 			cmd->error_string = "deny updating a hidden ref";
@@ -1486,23 +1485,23 @@
 				      const char *line,
 				      int linelen)
 {
-	unsigned char old_sha1[20], new_sha1[20];
+	struct object_id old_oid, new_oid;
 	struct command *cmd;
 	const char *refname;
 	int reflen;
+	const char *p;
 
-	if (linelen < 83 ||
-	    line[40] != ' ' ||
-	    line[81] != ' ' ||
-	    get_sha1_hex(line, old_sha1) ||
-	    get_sha1_hex(line + 41, new_sha1))
+	if (parse_oid_hex(line, &old_oid, &p) ||
+	    *p++ != ' ' ||
+	    parse_oid_hex(p, &new_oid, &p) ||
+	    *p++ != ' ')
 		die("protocol error: expected old/new/ref, got '%s'", line);
 
-	refname = line + 82;
-	reflen = linelen - 82;
+	refname = p;
+	reflen = linelen - (p - line);
 	FLEX_ALLOC_MEM(cmd, ref_name, refname, reflen);
-	hashcpy(cmd->old_sha1, old_sha1);
-	hashcpy(cmd->new_sha1, new_sha1);
+	oidcpy(&cmd->old_oid, &old_oid);
+	oidcpy(&cmd->new_oid, &new_oid);
 	*tail = cmd;
 	return &cmd->next;
 }
@@ -1524,12 +1523,12 @@
 
 	while (boc < eoc) {
 		const char *eol = memchr(boc, '\n', eoc - boc);
-		tail = queue_command(tail, boc, eol ? eol - boc : eoc - eol);
+		tail = queue_command(tail, boc, eol ? eol - boc : eoc - boc);
 		boc = eol ? eol + 1 : eoc;
 	}
 }
 
-static struct command *read_head_info(struct sha1_array *shallow)
+static struct command *read_head_info(struct oid_array *shallow)
 {
 	struct command *commands = NULL;
 	struct command **p = &commands;
@@ -1541,12 +1540,12 @@
 		if (!line)
 			break;
 
-		if (len == 48 && starts_with(line, "shallow ")) {
-			unsigned char sha1[20];
-			if (get_sha1_hex(line + 8, sha1))
+		if (len > 8 && starts_with(line, "shallow ")) {
+			struct object_id oid;
+			if (get_oid_hex(line + 8, &oid))
 				die("protocol error: expected shallow sha, got '%s'",
 				    line + 8);
-			sha1_array_append(shallow, sha1);
+			oid_array_append(shallow, &oid);
 			continue;
 		}
 
@@ -1634,12 +1633,17 @@
 
 static const char *pack_lockfile;
 
+static void push_header_arg(struct argv_array *args, struct pack_header *hdr)
+{
+	argv_array_pushf(args, "--pack_header=%"PRIu32",%"PRIu32,
+			ntohl(hdr->hdr_version), ntohl(hdr->hdr_entries));
+}
+
 static const char *unpack(int err_fd, struct shallow_info *si)
 {
 	struct pack_header hdr;
 	const char *hdr_err;
 	int status;
-	char hdr_arg[38];
 	struct child_process child = CHILD_PROCESS_INIT;
 	int fsck_objects = (receive_fsck_objects >= 0
 			    ? receive_fsck_objects
@@ -1653,9 +1657,6 @@
 			close(err_fd);
 		return hdr_err;
 	}
-	snprintf(hdr_arg, sizeof(hdr_arg),
-			"--pack_header=%"PRIu32",%"PRIu32,
-			ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
 
 	if (si->nr_ours || si->nr_theirs) {
 		alt_shallow_file = setup_temporary_shallow(si->shallow);
@@ -1679,7 +1680,8 @@
 	tmp_objdir_add_as_alternate(tmp_objdir);
 
 	if (ntohl(hdr.hdr_entries) < unpack_limit) {
-		argv_array_pushl(&child.args, "unpack-objects", hdr_arg, NULL);
+		argv_array_push(&child.args, "unpack-objects");
+		push_header_arg(&child.args, &hdr);
 		if (quiet)
 			argv_array_push(&child.args, "-q");
 		if (fsck_objects)
@@ -1695,12 +1697,12 @@
 		if (status)
 			return "unpack-objects abnormal exit";
 	} else {
-		char hostname[256];
+		char hostname[HOST_NAME_MAX + 1];
 
-		argv_array_pushl(&child.args, "index-pack",
-				 "--stdin", hdr_arg, NULL);
+		argv_array_pushl(&child.args, "index-pack", "--stdin", NULL);
+		push_header_arg(&child.args, &hdr);
 
-		if (gethostname(hostname, sizeof(hostname)))
+		if (xgethostname(hostname, sizeof(hostname)))
 			xsnprintf(hostname, sizeof(hostname), "localhost");
 		argv_array_pushf(&child.args,
 				 "--keep=receive-pack %"PRIuMAX" on %s",
@@ -1804,7 +1806,7 @@
 
 static void update_shallow_info(struct command *commands,
 				struct shallow_info *si,
-				struct sha1_array *ref)
+				struct oid_array *ref)
 {
 	struct command *cmd;
 	int *ref_status;
@@ -1815,9 +1817,9 @@
 	}
 
 	for (cmd = commands; cmd; cmd = cmd->next) {
-		if (is_null_sha1(cmd->new_sha1))
+		if (is_null_oid(&cmd->new_oid))
 			continue;
-		sha1_array_append(ref, cmd->new_sha1);
+		oid_array_append(ref, &cmd->new_oid);
 		cmd->index = ref->nr - 1;
 	}
 	si->ref = ref;
@@ -1830,7 +1832,7 @@
 	ALLOC_ARRAY(ref_status, ref->nr);
 	assign_shallow_commits_to_refs(si, NULL, ref_status);
 	for (cmd = commands; cmd; cmd = cmd->next) {
-		if (is_null_sha1(cmd->new_sha1))
+		if (is_null_oid(&cmd->new_oid))
 			continue;
 		if (ref_status[cmd->index]) {
 			cmd->error_string = "shallow update not allowed";
@@ -1868,7 +1870,7 @@
 {
 	struct command *cmd;
 	for (cmd = commands; cmd; cmd = cmd->next) {
-		if (!is_null_sha1(cmd->new_sha1))
+		if (!is_null_oid(&cmd->new_oid))
 			return 0;
 	}
 	return 1;
@@ -1878,8 +1880,8 @@
 {
 	int advertise_refs = 0;
 	struct command *commands;
-	struct sha1_array shallow = SHA1_ARRAY_INIT;
-	struct sha1_array ref = SHA1_ARRAY_INIT;
+	struct oid_array shallow = OID_ARRAY_INIT;
+	struct oid_array ref = OID_ARRAY_INIT;
 	struct shallow_info si;
 
 	struct option options[] = {
@@ -1971,8 +1973,8 @@
 	}
 	if (use_sideband)
 		packet_flush(1);
-	sha1_array_clear(&shallow);
-	sha1_array_clear(&ref);
+	oid_array_clear(&shallow);
+	oid_array_clear(&ref);
 	free((void *)push_cert_nonce);
 	return 0;
 }
diff --git a/builtin/replace.c b/builtin/replace.c
index f83e7b8..ab17668 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -93,28 +93,34 @@
 static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
 {
 	const char **p, *full_hex;
-	char ref[PATH_MAX];
+	struct strbuf ref = STRBUF_INIT;
+	size_t base_len;
 	int had_error = 0;
 	struct object_id oid;
 
+	strbuf_addstr(&ref, git_replace_ref_base);
+	base_len = ref.len;
+
 	for (p = argv; *p; p++) {
 		if (get_oid(*p, &oid)) {
 			error("Failed to resolve '%s' as a valid ref.", *p);
 			had_error = 1;
 			continue;
 		}
-		full_hex = oid_to_hex(&oid);
-		snprintf(ref, sizeof(ref), "%s%s", git_replace_ref_base, full_hex);
-		/* read_ref() may reuse the buffer */
-		full_hex = ref + strlen(git_replace_ref_base);
-		if (read_ref(ref, oid.hash)) {
+
+		strbuf_setlen(&ref, base_len);
+		strbuf_addstr(&ref, oid_to_hex(&oid));
+		full_hex = ref.buf + base_len;
+
+		if (read_ref(ref.buf, oid.hash)) {
 			error("replace ref '%s' not found.", full_hex);
 			had_error = 1;
 			continue;
 		}
-		if (fn(full_hex, ref, &oid))
+		if (fn(full_hex, ref.buf, &oid))
 			had_error = 1;
 	}
+	strbuf_release(&ref);
 	return had_error;
 }
 
@@ -129,21 +135,18 @@
 
 static void check_ref_valid(struct object_id *object,
 			    struct object_id *prev,
-			    char *ref,
-			    int ref_size,
+			    struct strbuf *ref,
 			    int force)
 {
-	if (snprintf(ref, ref_size,
-		     "%s%s", git_replace_ref_base,
-		     oid_to_hex(object)) > ref_size - 1)
-		die("replace ref name too long: %.*s...", 50, ref);
-	if (check_refname_format(ref, 0))
-		die("'%s' is not a valid ref name.", ref);
+	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);
 
-	if (read_ref(ref, prev->hash))
+	if (read_ref(ref->buf, prev->hash))
 		oidclr(prev);
 	else if (!force)
-		die("replace ref '%s' already exists", ref);
+		die("replace ref '%s' already exists", ref->buf);
 }
 
 static int replace_object_oid(const char *object_ref,
@@ -154,7 +157,7 @@
 {
 	struct object_id prev;
 	enum object_type obj_type, repl_type;
-	char ref[PATH_MAX];
+	struct strbuf ref = STRBUF_INIT;
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
 
@@ -167,16 +170,17 @@
 		    object_ref, typename(obj_type),
 		    replace_ref, typename(repl_type));
 
-	check_ref_valid(object, &prev, ref, sizeof(ref), force);
+	check_ref_valid(object, &prev, &ref, force);
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
-	    ref_transaction_update(transaction, ref, repl->hash, prev.hash,
+	    ref_transaction_update(transaction, ref.buf, repl->hash, prev.hash,
 				   0, NULL, &err) ||
 	    ref_transaction_commit(transaction, &err))
 		die("%s", err.buf);
 
 	ref_transaction_free(transaction);
+	strbuf_release(&ref);
 	return 0;
 }
 
@@ -280,7 +284,7 @@
 	char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
 	enum object_type type;
 	struct object_id old, new, prev;
-	char ref[PATH_MAX];
+	struct strbuf ref = STRBUF_INIT;
 
 	if (get_oid(object_ref, &old) < 0)
 		die("Not a valid object name: '%s'", object_ref);
@@ -289,7 +293,8 @@
 	if (type < 0)
 		die("unable to get object type for %s", oid_to_hex(&old));
 
-	check_ref_valid(&old, &prev, ref, sizeof(ref), force);
+	check_ref_valid(&old, &prev, &ref, force);
+	strbuf_release(&ref);
 
 	export_object(&old, type, raw, tmpfile);
 	if (launch_editor(tmpfile, NULL, NULL) < 0)
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 0aa93d5..bcf77f0 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -212,7 +212,7 @@
 static int show_bisect_vars(struct rev_list_info *info, int reaches, int all)
 {
 	int cnt, flags = info->flags;
-	char hex[GIT_SHA1_HEXSZ + 1] = "";
+	char hex[GIT_MAX_HEXSZ + 1] = "";
 	struct commit_list *tried;
 	struct rev_info *revs = info->revs;
 
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 9e53a1a..0513330 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -205,21 +205,22 @@
 	return 0;
 }
 
-static int show_abbrev(const unsigned char *sha1, void *cb_data)
+static int show_abbrev(const struct object_id *oid, void *cb_data)
 {
-	show_rev(NORMAL, sha1, NULL);
+	show_rev(NORMAL, oid->hash, NULL);
 	return 0;
 }
 
 static void show_datestring(const char *flag, const char *datestr)
 {
-	static char buffer[100];
+	char *buffer;
 
 	/* date handling requires both flags and revs */
 	if ((filter & (DO_FLAGS | DO_REVS)) != (DO_FLAGS | DO_REVS))
 		return;
-	snprintf(buffer, sizeof(buffer), "%s%lu", flag, approxidate(datestr));
+	buffer = xstrfmt("%s%lu", flag, approxidate(datestr));
 	show(buffer);
+	free(buffer);
 }
 
 static int show_file(const char *arg, int output_prefix)
diff --git a/builtin/send-pack.c b/builtin/send-pack.c
index 832fd7e..b8e2e74 100644
--- a/builtin/send-pack.c
+++ b/builtin/send-pack.c
@@ -131,8 +131,8 @@
 	const char *dest = NULL;
 	int fd[2];
 	struct child_process *conn;
-	struct sha1_array extra_have = SHA1_ARRAY_INIT;
-	struct sha1_array shallow = SHA1_ARRAY_INIT;
+	struct oid_array extra_have = OID_ARRAY_INIT;
+	struct oid_array shallow = OID_ARRAY_INIT;
 	struct ref *remote_refs, *local_refs;
 	int ret;
 	int helper_status = 0;
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index be316bb..566a5b6 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -270,6 +270,29 @@
 	return result;
 }
 
+static void module_list_active(struct module_list *list)
+{
+	int i;
+	struct module_list active_modules = MODULE_LIST_INIT;
+
+	gitmodules_config();
+
+	for (i = 0; i < list->nr; i++) {
+		const struct cache_entry *ce = list->entries[i];
+
+		if (!is_submodule_initialized(ce->name))
+			continue;
+
+		ALLOC_GROW(active_modules.entries,
+			   active_modules.nr + 1,
+			   active_modules.alloc);
+		active_modules.entries[active_modules.nr++] = ce;
+	}
+
+	free(list->entries);
+	*list = active_modules;
+}
+
 static int module_list(int argc, const char **argv, const char *prefix)
 {
 	int i;
@@ -334,6 +357,18 @@
 			displaypath);
 
 	/*
+	 * NEEDSWORK: In a multi-working-tree world, this needs to be
+	 * set in the per-worktree config.
+	 *
+	 * Set active flag for the submodule being initialized
+	 */
+	if (!is_submodule_initialized(path)) {
+		strbuf_reset(&sb);
+		strbuf_addf(&sb, "submodule.%s.active", sub->name);
+		git_config_set_gently(sb.buf, "true");
+	}
+
+	/*
 	 * Copy url setting when it is not set yet.
 	 * To look up the url in .git/config, we must not fall back to
 	 * .gitmodules, so look it up directly.
@@ -341,12 +376,12 @@
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.url", sub->name);
 	if (git_config_get_string(sb.buf, &url)) {
-		url = xstrdup(sub->url);
-
-		if (!url)
+		if (!sub->url)
 			die(_("No url found for submodule path '%s' in .gitmodules"),
 				displaypath);
 
+		url = xstrdup(sub->url);
+
 		/* Possibly a url relative to parent */
 		if (starts_with_dot_dot_slash(url) ||
 		    starts_with_dot_slash(url)) {
@@ -420,6 +455,13 @@
 	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
 		return 1;
 
+	/*
+	 * If there are no path args and submodule.active is set then,
+	 * by default, only initialize 'active' modules.
+	 */
+	if (!argc && git_config_get_value_multi("submodule.active"))
+		module_list_active(&list);
+
 	for (i = 0; i < list.nr; i++)
 		init_submodule(list.entries[i]->name, prefix, quiet);
 
@@ -741,7 +783,6 @@
 	struct strbuf displaypath_sb = STRBUF_INIT;
 	struct strbuf sb = STRBUF_INIT;
 	const char *displaypath = NULL;
-	char *url = NULL;
 	int needs_cloning = 0;
 
 	if (ce_stage(ce)) {
@@ -775,15 +816,8 @@
 		goto cleanup;
 	}
 
-	/*
-	 * Looking up the url in .git/config.
-	 * We must not fall back to .gitmodules as we only want
-	 * to process configured submodules.
-	 */
-	strbuf_reset(&sb);
-	strbuf_addf(&sb, "submodule.%s.url", sub->name);
-	git_config_get_string(sb.buf, &url);
-	if (!url) {
+	/* Check if the submodule has been initialized. */
+	if (!is_submodule_initialized(ce->name)) {
 		next_submodule_warn_missing(suc, out, displaypath);
 		goto cleanup;
 	}
@@ -817,7 +851,7 @@
 		argv_array_push(&child->args, "--depth=1");
 	argv_array_pushl(&child->args, "--path", sub->path, NULL);
 	argv_array_pushl(&child->args, "--name", sub->name, NULL);
-	argv_array_pushl(&child->args, "--url", url, NULL);
+	argv_array_pushl(&child->args, "--url", sub->url, NULL);
 	if (suc->references.nr) {
 		struct string_list_item *item;
 		for_each_string_list_item(item, &suc->references)
@@ -827,7 +861,6 @@
 		argv_array_push(&child->args, suc->depth);
 
 cleanup:
-	free(url);
 	strbuf_reset(&displaypath_sb);
 	strbuf_reset(&sb);
 
@@ -1072,6 +1105,50 @@
 	return 0;
 }
 
+static int push_check(int argc, const char **argv, const char *prefix)
+{
+	struct remote *remote;
+
+	if (argc < 2)
+		die("submodule--helper push-check requires at least 1 argument");
+
+	/*
+	 * The remote must be configured.
+	 * This is to avoid pushing to the exact same URL as the parent.
+	 */
+	remote = pushremote_get(argv[1]);
+	if (!remote || remote->origin == REMOTE_UNCONFIGURED)
+		die("remote '%s' not configured", argv[1]);
+
+	/* Check the refspec */
+	if (argc > 2) {
+		int i, refspec_nr = argc - 2;
+		struct ref *local_refs = get_local_heads();
+		struct refspec *refspec = parse_push_refspec(refspec_nr,
+							     argv + 2);
+
+		for (i = 0; i < refspec_nr; i++) {
+			struct refspec *rs = refspec + i;
+
+			if (rs->pattern || rs->matching)
+				continue;
+
+			/*
+			 * LHS must match a single ref
+			 * NEEDSWORK: add logic to special case 'HEAD' once
+			 * working with submodules in a detached head state
+			 * ceases to be the norm.
+			 */
+			if (count_refspec_match(rs->src, local_refs, NULL) != 1)
+				die("src refspec '%s' must name a ref",
+				    rs->src);
+		}
+		free_refspec(refspec_nr, refspec);
+	}
+
+	return 0;
+}
+
 static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
 {
 	int i;
@@ -1109,6 +1186,16 @@
 	return 0;
 }
 
+static int is_active(int argc, const char **argv, const char *prefix)
+{
+	if (argc != 2)
+		die("submodule--helper is-active takes exactly 1 argument");
+
+	gitmodules_config();
+
+	return !is_submodule_initialized(argv[1]);
+}
+
 #define SUPPORT_SUPER_PREFIX (1<<0)
 
 struct cmd_struct {
@@ -1127,7 +1214,9 @@
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
 	{"init", module_init, SUPPORT_SUPER_PREFIX},
 	{"remote-branch", resolve_remote_submodule_branch, 0},
+	{"push-check", push_check, 0},
 	{"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
+	{"is-active", is_active, 0},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)
diff --git a/builtin/tag.c b/builtin/tag.c
index ad29be6..bdf1e88 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -22,7 +22,7 @@
 static const char * const git_tag_usage[] = {
 	N_("git tag [-a | -s | -u <key-id>] [-f] [-m <msg> | -F <file>] <tagname> [<head>]"),
 	N_("git tag -d <tagname>..."),
-	N_("git tag -l [-n[<num>]] [--contains <commit>] [--points-at <object>]"
+	N_("git tag -l [-n[<num>]] [--contains <commit>] [--no-contains <commit>] [--points-at <object>]"
 		"\n\t\t[--format=<format>] [--[no-]merged [<commit>]] [<pattern>...]"),
 	N_("git tag -v [--format=<format>] <tagname>..."),
 	NULL
@@ -72,25 +72,22 @@
 			     const void *cb_data)
 {
 	const char **p;
-	char ref[PATH_MAX];
+	struct strbuf ref = STRBUF_INIT;
 	int had_error = 0;
 	unsigned char sha1[20];
 
 	for (p = argv; *p; p++) {
-		if (snprintf(ref, sizeof(ref), "refs/tags/%s", *p)
-					>= sizeof(ref)) {
-			error(_("tag name too long: %.*s..."), 50, *p);
-			had_error = 1;
-			continue;
-		}
-		if (read_ref(ref, sha1)) {
+		strbuf_reset(&ref);
+		strbuf_addf(&ref, "refs/tags/%s", *p);
+		if (read_ref(ref.buf, sha1)) {
 			error(_("tag '%s' not found."), *p);
 			had_error = 1;
 			continue;
 		}
-		if (fn(*p, ref, sha1, cb_data))
+		if (fn(*p, ref.buf, sha1, cb_data))
 			had_error = 1;
 	}
+	strbuf_release(&ref);
 	return had_error;
 }
 
@@ -231,26 +228,22 @@
 		       unsigned char *prev, unsigned char *result)
 {
 	enum object_type type;
-	char header_buf[1024];
-	int header_len;
+	struct strbuf header = STRBUF_INIT;
 	char *path = NULL;
 
 	type = sha1_object_info(object, NULL);
 	if (type <= OBJ_NONE)
 	    die(_("bad object type."));
 
-	header_len = snprintf(header_buf, sizeof(header_buf),
-			  "object %s\n"
-			  "type %s\n"
-			  "tag %s\n"
-			  "tagger %s\n\n",
-			  sha1_to_hex(object),
-			  typename(type),
-			  tag,
-			  git_committer_info(IDENT_STRICT));
-
-	if (header_len > sizeof(header_buf) - 1)
-		die(_("tag header too big."));
+	strbuf_addf(&header,
+		    "object %s\n"
+		    "type %s\n"
+		    "tag %s\n"
+		    "tagger %s\n\n",
+		    sha1_to_hex(object),
+		    typename(type),
+		    tag,
+		    git_committer_info(IDENT_STRICT));
 
 	if (!opt->message_given) {
 		int fd;
@@ -288,7 +281,8 @@
 	if (!opt->message_given && !buf->len)
 		die(_("no tag message?"));
 
-	strbuf_insert(buf, 0, header_buf, header_len);
+	strbuf_insert(buf, 0, header.buf, header.len);
+	strbuf_release(&header);
 
 	if (build_tag_object(buf, opt->sign, result) < 0) {
 		if (path)
@@ -315,7 +309,7 @@
 	if (rla) {
 		strbuf_addstr(sb, rla);
 	} else {
-		strbuf_addstr(sb, _("tag: tagging "));
+		strbuf_addstr(sb, "tag: tagging ");
 		strbuf_add_unique_abbrev(sb, sha1, DEFAULT_ABBREV);
 	}
 
@@ -323,14 +317,14 @@
 	type = sha1_object_info(sha1, NULL);
 	switch (type) {
 	default:
-		strbuf_addstr(sb, _("object of unknown type"));
+		strbuf_addstr(sb, "object of unknown type");
 		break;
 	case OBJ_COMMIT:
 		if ((buf = read_sha1_file(sha1, &type, &size)) != NULL) {
 			subject_len = find_commit_subject(buf, &subject_start);
 			strbuf_insert(sb, sb->len, subject_start, subject_len);
 		} else {
-			strbuf_addstr(sb, _("commit object"));
+			strbuf_addstr(sb, "commit object");
 		}
 		free(buf);
 
@@ -338,13 +332,13 @@
 			strbuf_addf(sb, ", %s", show_date(c->date, 0, DATE_MODE(SHORT)));
 		break;
 	case OBJ_TREE:
-		strbuf_addstr(sb, _("tree object"));
+		strbuf_addstr(sb, "tree object");
 		break;
 	case OBJ_BLOB:
-		strbuf_addstr(sb, _("blob object"));
+		strbuf_addstr(sb, "blob object");
 		break;
 	case OBJ_TAG:
-		strbuf_addstr(sb, _("other tag object"));
+		strbuf_addstr(sb, "other tag object");
 		break;
 	}
 	strbuf_addch(sb, ')');
@@ -424,14 +418,17 @@
 		OPT_GROUP(N_("Tag listing options")),
 		OPT_COLUMN(0, "column", &colopts, N_("show tag list in columns")),
 		OPT_CONTAINS(&filter.with_commit, N_("print only tags that contain the commit")),
+		OPT_NO_CONTAINS(&filter.no_commit, N_("print only tags that don't contain the commit")),
 		OPT_WITH(&filter.with_commit, N_("print only tags that contain the commit")),
+		OPT_WITHOUT(&filter.no_commit, N_("print only tags that don't contain the commit")),
 		OPT_MERGED(&filter, N_("print only tags that are merged")),
 		OPT_NO_MERGED(&filter, N_("print only tags that are not merged")),
 		OPT_CALLBACK(0 , "sort", sorting_tail, N_("key"),
 			     N_("field name to sort on"), &parse_opt_ref_sorting),
 		{
 			OPTION_CALLBACK, 0, "points-at", &filter.points_at, N_("object"),
-			N_("print only tags of the object"), 0, parse_opt_object_name
+			N_("print only tags of the object"), PARSE_OPT_LASTARG_DEFAULT,
+			parse_opt_object_name, (intptr_t) "HEAD"
 		},
 		OPT_STRING(  0 , "format", &format, N_("format"), N_("format to use for the output")),
 		OPT_BOOL('i', "ignore-case", &icase, N_("sorting and filtering are case insensitive")),
@@ -454,8 +451,14 @@
 	}
 	create_tag_object = (opt.sign || annotate || msg.given || msgfile);
 
-	if (argc == 0 && !cmdmode)
-		cmdmode = 'l';
+	if (!cmdmode) {
+		if (argc == 0)
+			cmdmode = 'l';
+		else if (filter.with_commit || filter.no_commit ||
+			 filter.points_at.nr || filter.merge_commit ||
+			 filter.lines != -1)
+			cmdmode = 'l';
+	}
 
 	if ((create_tag_object || force) && (cmdmode != 0))
 		usage_with_options(git_tag_usage, options);
@@ -485,13 +488,15 @@
 		return ret;
 	}
 	if (filter.lines != -1)
-		die(_("-n option is only allowed with -l."));
+		die(_("-n option is only allowed in list mode"));
 	if (filter.with_commit)
-		die(_("--contains option is only allowed with -l."));
+		die(_("--contains option is only allowed in list mode"));
+	if (filter.no_commit)
+		die(_("--no-contains option is only allowed in list mode"));
 	if (filter.points_at.nr)
-		die(_("--points-at option is only allowed with -l."));
+		die(_("--points-at option is only allowed in list mode"));
 	if (filter.merge_commit)
-		die(_("--merged and --no-merged option are only allowed with -l"));
+		die(_("--merged and --no-merged options are only allowed in list mode"));
 	if (cmdmode == 'd')
 		return for_each_tag_name(argv, delete_tag, NULL);
 	if (cmdmode == 'v') {
diff --git a/builtin/update-index.c b/builtin/update-index.c
index d74d72c..ebfc09f 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -125,12 +125,16 @@
 	struct stat st;
 	struct stat_data base;
 	int fd, ret = 0;
+	char *cwd;
 
 	strbuf_addstr(&mtime_dir, "mtime-test-XXXXXX");
 	if (!mkdtemp(mtime_dir.buf))
 		die_errno("Could not make temporary directory");
 
-	fprintf(stderr, _("Testing mtime in '%s' "), xgetcwd());
+	cwd = xgetcwd();
+	fprintf(stderr, _("Testing mtime in '%s' "), cwd);
+	free(cwd);
+
 	atexit(remove_test_directory);
 	xstat_mtime_dir(&st);
 	fill_stat_data(&base, &st);
diff --git a/builtin/worktree.c b/builtin/worktree.c
index 9993ded..1722a9b 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -24,6 +24,7 @@
 	int force;
 	int detach;
 	int checkout;
+	int keep_locked;
 	const char *new_branch;
 	int force_new_branch;
 };
@@ -106,8 +107,7 @@
 			printf("%s\n", reason.buf);
 		if (show_only)
 			continue;
-		strbuf_reset(&path);
-		strbuf_addstr(&path, git_path("worktrees/%s", d->d_name));
+		git_path_buf(&path, "worktrees/%s", d->d_name);
 		ret = remove_dir_recursively(&path, 0);
 		if (ret < 0 && errno == ENOTDIR)
 			ret = unlink(path.buf);
@@ -215,8 +215,7 @@
 	}
 
 	name = worktree_basename(path, &len);
-	strbuf_addstr(&sb_repo,
-		      git_path("worktrees/%.*s", (int)(path + len - name), name));
+	git_path_buf(&sb_repo, "worktrees/%.*s", (int)(path + len - name), name);
 	len = sb_repo.len;
 	if (safe_create_leading_directories_const(sb_repo.buf))
 		die_errno(_("could not create leading directories of '%s'"),
@@ -242,7 +241,10 @@
 	 * after the preparation is over.
 	 */
 	strbuf_addf(&sb, "%s/locked", sb_repo.buf);
-	write_file(sb.buf, "initializing");
+	if (!opts->keep_locked)
+		write_file(sb.buf, "initializing");
+	else
+		write_file(sb.buf, "added with --lock");
 
 	strbuf_addf(&sb_git, "%s/.git", path);
 	if (safe_create_leading_directories_const(sb_git.buf))
@@ -303,9 +305,11 @@
 	junk_git_dir = NULL;
 
 done:
-	strbuf_reset(&sb);
-	strbuf_addf(&sb, "%s/locked", sb_repo.buf);
-	unlink_or_warn(sb.buf);
+	if (ret || !opts->keep_locked) {
+		strbuf_reset(&sb);
+		strbuf_addf(&sb, "%s/locked", sb_repo.buf);
+		unlink_or_warn(sb.buf);
+	}
 	argv_array_clear(&child_env);
 	strbuf_release(&sb);
 	strbuf_release(&symref);
@@ -328,6 +332,7 @@
 			   N_("create or reset a branch")),
 		OPT_BOOL(0, "detach", &opts.detach, N_("detach HEAD at named commit")),
 		OPT_BOOL(0, "checkout", &opts.checkout, N_("populate the new working tree")),
+		OPT_BOOL(0, "lock", &opts.keep_locked, N_("keep the new working tree locked")),
 		OPT_END()
 	};
 
diff --git a/cache.h b/cache.h
index ed3c592..e1f0e18 100644
--- a/cache.h
+++ b/cache.h
@@ -66,8 +66,12 @@
 #define GIT_SHA1_RAWSZ 20
 #define GIT_SHA1_HEXSZ (2 * GIT_SHA1_RAWSZ)
 
+/* The length in byte and in hex digits of the largest possible hash value. */
+#define GIT_MAX_RAWSZ GIT_SHA1_RAWSZ
+#define GIT_MAX_HEXSZ GIT_SHA1_HEXSZ
+
 struct object_id {
-	unsigned char hash[GIT_SHA1_RAWSZ];
+	unsigned char hash[GIT_MAX_RAWSZ];
 };
 
 #if defined(DT_UNKNOWN) && !defined(NO_D_TYPE_IN_DIRENT)
@@ -411,6 +415,7 @@
 #define GIT_WORK_TREE_ENVIRONMENT "GIT_WORK_TREE"
 #define GIT_PREFIX_ENVIRONMENT "GIT_PREFIX"
 #define GIT_SUPER_PREFIX_ENVIRONMENT "GIT_INTERNAL_SUPER_PREFIX"
+#define GIT_TOPLEVEL_PREFIX_ENVIRONMENT "GIT_INTERNAL_TOPLEVEL_PREFIX"
 #define DEFAULT_GIT_DIR_ENVIRONMENT ".git"
 #define DB_ENVIRONMENT "GIT_OBJECT_DIRECTORY"
 #define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
@@ -594,6 +599,7 @@
 extern int discard_index(struct index_state *);
 extern int unmerged_index(const struct index_state *);
 extern int verify_path(const char *path);
+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);
 extern struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int igncase);
@@ -979,7 +985,7 @@
 extern const char *find_unique_abbrev(const unsigned char *sha1, int len);
 extern int find_unique_abbrev_r(char *hex, const unsigned char *sha1, int len);
 
-extern const unsigned char null_sha1[GIT_SHA1_RAWSZ];
+extern const unsigned char null_sha1[GIT_MAX_RAWSZ];
 extern const struct object_id null_oid;
 
 static inline int hashcmp(const unsigned char *sha1, const unsigned char *sha2)
@@ -1161,7 +1167,7 @@
 int raceproof_create_file(const char *path, create_file_fn fn, void *cb);
 
 int mkdir_in_gitdir(const char *path);
-extern char *expand_user_path(const char *path);
+extern char *expand_user_path(const char *path, int real_home);
 const char *enter_repo(const char *path, int strict);
 static inline int is_absolute_path(const char *path)
 {
@@ -1361,7 +1367,7 @@
 
 extern int get_oid(const char *str, struct object_id *oid);
 
-typedef int each_abbrev_fn(const unsigned char *sha1, void *);
+typedef int each_abbrev_fn(const struct object_id *oid, void *);
 extern int for_each_abbrev(const char *prefix, each_abbrev_fn, void *);
 
 extern int set_disambiguate_hint_config(const char *var, const char *value);
@@ -1676,9 +1682,12 @@
 extern void pack_report(void);
 
 /*
- * Create a temporary file rooted in the object database directory.
+ * Create a temporary file rooted in the object database directory, or
+ * die on failure. The filename is taken from "pattern", which should have the
+ * usual "XXXXXX" trailer, and the resulting filename is written into the
+ * "template" buffer. Returns the open descriptor.
  */
-extern int odb_mkstemp(char *template, size_t limit, const char *pattern);
+extern int odb_mkstemp(struct strbuf *template, const char *pattern);
 
 /*
  * Generate the filename to be used for a pack file with checksum "sha1" and
@@ -1883,6 +1892,11 @@
 	CONFIG_ORIGIN_CMDLINE
 };
 
+struct config_options {
+	unsigned int respect_includes : 1;
+	const char *git_dir;
+};
+
 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 *);
@@ -1896,12 +1910,13 @@
 extern void git_config(config_fn_t fn, void *);
 extern int git_config_with_options(config_fn_t fn, void *,
 				   struct git_config_source *config_source,
-				   int respect_includes);
+				   const struct config_options *opts);
 extern int git_parse_ulong(const char *, unsigned long *);
 extern int git_parse_maybe_bool(const char *);
 extern int git_config_int(const char *, const char *);
 extern int64_t git_config_int64(const char *, const char *);
 extern unsigned long git_config_ulong(const char *, const char *);
+extern ssize_t git_config_ssize_t(const char *, const char *);
 extern int git_config_bool_or_int(const char *, const char *, int *);
 extern int git_config_bool(const char *, const char *);
 extern int git_config_maybe_bool(const char *, const char *);
@@ -1948,6 +1963,7 @@
 	int depth;
 	config_fn_t fn;
 	void *data;
+	const struct config_options *opts;
 };
 #define CONFIG_INCLUDE_INIT { 0 }
 extern int git_config_include(const char *name, const char *value, void *data);
diff --git a/ci/run-windows-build.sh b/ci/run-windows-build.sh
new file mode 100755
index 0000000..d8f0d92
--- /dev/null
+++ b/ci/run-windows-build.sh
@@ -0,0 +1,74 @@
+#!/usr/bin/env bash
+#
+# Script to trigger the Git for Windows build and test run.
+# Set the $GFW_CI_TOKEN as environment variable.
+# Pass the branch (only branches on https://github.com/git/git are
+# supported) and a commit hash.
+#
+
+test $# -ne 2 && echo "Unexpected number of parameters" && exit 1
+test -z "$GFW_CI_TOKEN" && echo "GFW_CI_TOKEN not defined" && exit
+
+BRANCH=$1
+COMMIT=$2
+
+gfwci () {
+	local CURL_ERROR_CODE HTTP_CODE
+	exec 3>&1
+	HTTP_CODE=$(curl \
+		-H "Authentication: Bearer $GFW_CI_TOKEN" \
+		--silent --retry 5 --write-out '%{HTTP_CODE}' \
+		--output >(sed "$(printf '1s/^\xef\xbb\xbf//')" >cat >&3) \
+		"https://git-for-windows-ci.azurewebsites.net/api/TestNow?$1" \
+	)
+	CURL_ERROR_CODE=$?
+	if test $CURL_ERROR_CODE -ne 0
+	then
+		return $CURL_ERROR_CODE
+	fi
+	if test "$HTTP_CODE" -ge 400 && test "$HTTP_CODE" -lt 600
+	then
+		return 127
+	fi
+}
+
+# Trigger build job
+BUILD_ID=$(gfwci "action=trigger&branch=$BRANCH&commit=$COMMIT&skipTests=false")
+if test $? -ne 0
+then
+	echo "Unable to trigger Visual Studio Team Services Build"
+	echo "$BUILD_ID"
+	exit 1
+fi
+
+# Check if the $BUILD_ID contains a number
+case $BUILD_ID in
+''|*[!0-9]*) echo "Unexpected build number: $BUILD_ID" && exit 1
+esac
+
+echo "Visual Studio Team Services Build #${BUILD_ID}"
+
+# Wait until build job finished
+STATUS=
+RESULT=
+while true
+do
+	LAST_STATUS=$STATUS
+	STATUS=$(gfwci "action=status&buildId=$BUILD_ID")
+	test "$STATUS" = "$LAST_STATUS" || printf "\nStatus: %s " "$STATUS"
+	printf "."
+
+	case "$STATUS" in
+	inProgress|postponed|notStarted) sleep 10               ;; # continue
+		 "completed: succeeded") RESULT="success"; break;; # success
+	*) echo "Unhandled status: $STATUS";               break;; # failure
+	esac
+done
+
+# Print log
+echo ""
+echo ""
+gfwci "action=log&buildId=$BUILD_ID" | cut -c 30-
+
+# Set exit code for TravisCI
+test "$RESULT" = "success"
diff --git a/combine-diff.c b/combine-diff.c
index 59501db..2848034 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -292,9 +292,10 @@
 	enum object_type type;
 
 	if (S_ISGITLINK(mode)) {
-		blob = xmalloc(100);
-		*size = snprintf(blob, 100,
-				 "Subproject commit %s\n", oid_to_hex(oid));
+		struct strbuf buf = STRBUF_INIT;
+		strbuf_addf(&buf, "Subproject commit %s\n", oid_to_hex(oid));
+		*size = buf.len;
+		blob = strbuf_detach(&buf, NULL);
 	} else if (is_null_oid(oid)) {
 		/* deleted blob */
 		*size = 0;
@@ -1311,7 +1312,7 @@
 
 /* find set of paths that every parent touches */
 static struct combine_diff_path *find_paths_generic(const unsigned char *sha1,
-	const struct sha1_array *parents, struct diff_options *opt)
+	const struct oid_array *parents, struct diff_options *opt)
 {
 	struct combine_diff_path *paths = NULL;
 	int i, num_parent = parents->nr;
@@ -1335,7 +1336,7 @@
 			opt->output_format = stat_opt;
 		else
 			opt->output_format = DIFF_FORMAT_NO_OUTPUT;
-		diff_tree_sha1(parents->sha1[i], sha1, "", opt);
+		diff_tree_sha1(parents->oid[i].hash, sha1, "", opt);
 		diffcore_std(opt);
 		paths = intersect_paths(paths, i, num_parent);
 
@@ -1359,7 +1360,7 @@
  * rename/copy detection, etc, comparing all trees simultaneously (= faster).
  */
 static struct combine_diff_path *find_paths_multitree(
-	const unsigned char *sha1, const struct sha1_array *parents,
+	const unsigned char *sha1, const struct oid_array *parents,
 	struct diff_options *opt)
 {
 	int i, nparent = parents->nr;
@@ -1369,7 +1370,7 @@
 
 	ALLOC_ARRAY(parents_sha1, nparent);
 	for (i = 0; i < nparent; i++)
-		parents_sha1[i] = parents->sha1[i];
+		parents_sha1[i] = parents->oid[i].hash;
 
 	/* fake list head, so worker can assume it is non-NULL */
 	paths_head.next = NULL;
@@ -1384,7 +1385,7 @@
 
 
 void diff_tree_combined(const unsigned char *sha1,
-			const struct sha1_array *parents,
+			const struct oid_array *parents,
 			int dense,
 			struct rev_info *rev)
 {
@@ -1462,7 +1463,7 @@
 		if (stat_opt) {
 			diffopts.output_format = stat_opt;
 
-			diff_tree_sha1(parents->sha1[0], sha1, "", &diffopts);
+			diff_tree_sha1(parents->oid[0].hash, sha1, "", &diffopts);
 			diffcore_std(&diffopts);
 			if (opt->orderfile)
 				diffcore_order(opt->orderfile);
@@ -1532,12 +1533,12 @@
 			      struct rev_info *rev)
 {
 	struct commit_list *parent = get_saved_parents(rev, commit);
-	struct sha1_array parents = SHA1_ARRAY_INIT;
+	struct oid_array parents = OID_ARRAY_INIT;
 
 	while (parent) {
-		sha1_array_append(&parents, parent->item->object.oid.hash);
+		oid_array_append(&parents, &parent->item->object.oid);
 		parent = parent->next;
 	}
 	diff_tree_combined(commit->object.oid.hash, &parents, dense, rev);
-	sha1_array_clear(&parents);
+	oid_array_clear(&parents);
 }
diff --git a/commit.h b/commit.h
index 528272a..7b1986d 100644
--- a/commit.h
+++ b/commit.h
@@ -261,7 +261,7 @@
 /* largest positive number a signed 32-bit integer can contain */
 #define INFINITE_DEPTH 0x7fffffff
 
-struct sha1_array;
+struct oid_array;
 struct ref;
 extern int register_shallow(const unsigned char *sha1);
 extern int unregister_shallow(const unsigned char *sha1);
@@ -273,18 +273,18 @@
 		int ac, const char **av, int shallow_flag, int not_shallow_flag);
 extern void set_alternate_shallow_file(const char *path, int override);
 extern int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
-				 const struct sha1_array *extra);
+				 const struct oid_array *extra);
 extern void setup_alternate_shallow(struct lock_file *shallow_lock,
 				    const char **alternate_shallow_file,
-				    const struct sha1_array *extra);
-extern const char *setup_temporary_shallow(const struct sha1_array *extra);
+				    const struct oid_array *extra);
+extern const char *setup_temporary_shallow(const struct oid_array *extra);
 extern void advertise_shallow_grafts(int);
 
 struct shallow_info {
-	struct sha1_array *shallow;
+	struct oid_array *shallow;
 	int *ours, nr_ours;
 	int *theirs, nr_theirs;
-	struct sha1_array *ref;
+	struct oid_array *ref;
 
 	/* for receive-pack */
 	uint32_t **used_shallow;
@@ -295,7 +295,7 @@
 	int nr_commits;
 };
 
-extern void prepare_shallow_info(struct shallow_info *, struct sha1_array *);
+extern void prepare_shallow_info(struct shallow_info *, struct oid_array *);
 extern void clear_shallow_info(struct shallow_info *);
 extern void remove_nonexistent_theirs_shallow(struct shallow_info *);
 extern void assign_shallow_commits_to_refs(struct shallow_info *info,
diff --git a/config.c b/config.c
index 1a4d855..b4a3205 100644
--- a/config.c
+++ b/config.c
@@ -135,7 +135,7 @@
 	if (!path)
 		return config_error_nonbool("include.path");
 
-	expanded = expand_user_path(path);
+	expanded = expand_user_path(path, 0);
 	if (!expanded)
 		return error("could not expand include path '%s'", path);
 	path = expanded;
@@ -177,7 +177,7 @@
 	char *expanded;
 	int prefix = 0;
 
-	expanded = expand_user_path(pat->buf);
+	expanded = expand_user_path(pat->buf, 1);
 	if (expanded) {
 		strbuf_reset(pat);
 		strbuf_addstr(pat, expanded);
@@ -191,7 +191,7 @@
 			return error(_("relative config include "
 				       "conditionals must come from files"));
 
-		strbuf_add_absolute_path(&path, cf->path);
+		strbuf_realpath(&path, cf->path, 1);
 		slash = find_last_dir_sep(path.buf);
 		if (!slash)
 			die("BUG: how is this possible?");
@@ -207,13 +207,22 @@
 	return prefix;
 }
 
-static int include_by_gitdir(const char *cond, size_t cond_len, int icase)
+static int include_by_gitdir(const struct config_options *opts,
+			     const char *cond, size_t cond_len, int icase)
 {
 	struct strbuf text = STRBUF_INIT;
 	struct strbuf pattern = STRBUF_INIT;
 	int ret = 0, prefix;
+	const char *git_dir;
 
-	strbuf_add_absolute_path(&text, get_git_dir());
+	if (opts->git_dir)
+		git_dir = opts->git_dir;
+	else if (have_git_dir())
+		git_dir = get_git_dir();
+	else
+		goto done;
+
+	strbuf_realpath(&text, git_dir, 1);
 	strbuf_add(&pattern, cond, cond_len);
 	prefix = prepare_include_condition_pattern(&pattern);
 
@@ -242,13 +251,14 @@
 	return ret;
 }
 
-static int include_condition_is_true(const char *cond, size_t cond_len)
+static int include_condition_is_true(const struct config_options *opts,
+				     const char *cond, size_t cond_len)
 {
 
 	if (skip_prefix_mem(cond, cond_len, "gitdir:", &cond, &cond_len))
-		return include_by_gitdir(cond, cond_len, 0);
+		return include_by_gitdir(opts, cond, cond_len, 0);
 	else if (skip_prefix_mem(cond, cond_len, "gitdir/i:", &cond, &cond_len))
-		return include_by_gitdir(cond, cond_len, 1);
+		return include_by_gitdir(opts, cond, cond_len, 1);
 
 	/* unknown conditionals are always false */
 	return 0;
@@ -273,7 +283,7 @@
 		ret = handle_path_include(value, inc);
 
 	if (!parse_config_key(var, "includeif", &cond, &cond_len, &key) &&
-	    (cond && include_condition_is_true(cond, cond_len)) &&
+	    (cond && include_condition_is_true(inc->opts, cond, cond_len)) &&
 	    !strcmp(key, "path"))
 		ret = handle_path_include(value, inc);
 
@@ -834,6 +844,15 @@
 	return 1;
 }
 
+static int git_parse_ssize_t(const char *value, ssize_t *ret)
+{
+	intmax_t tmp;
+	if (!git_parse_signed(value, &tmp, maximum_signed_value_of_type(ssize_t)))
+		return 0;
+	*ret = tmp;
+	return 1;
+}
+
 NORETURN
 static void die_bad_number(const char *name, const char *value)
 {
@@ -892,6 +911,14 @@
 	return ret;
 }
 
+ssize_t git_config_ssize_t(const char *name, const char *value)
+{
+	ssize_t ret;
+	if (!git_parse_ssize_t(value, &ret))
+		die_bad_number(name, value);
+	return ret;
+}
+
 int git_parse_maybe_bool(const char *value)
 {
 	if (!value)
@@ -948,7 +975,7 @@
 {
 	if (!value)
 		return config_error_nonbool(var);
-	*dest = expand_user_path(value);
+	*dest = expand_user_path(value, 0);
 	if (!*dest)
 		die(_("failed to expand user dir in: '%s'"), value);
 	return 0;
@@ -1494,12 +1521,20 @@
 	return !git_env_bool("GIT_CONFIG_NOSYSTEM", 0);
 }
 
-static int do_git_config_sequence(config_fn_t fn, void *data)
+static int do_git_config_sequence(const struct config_options *opts,
+				  config_fn_t fn, void *data)
 {
 	int ret = 0;
 	char *xdg_config = xdg_config_home("config");
-	char *user_config = expand_user_path("~/.gitconfig");
-	char *repo_config = have_git_dir() ? git_pathdup("config") : NULL;
+	char *user_config = expand_user_path("~/.gitconfig", 0);
+	char *repo_config;
+
+	if (opts->git_dir)
+		repo_config = mkpathdup("%s/config", opts->git_dir);
+	else if (have_git_dir())
+		repo_config = git_pathdup("config");
+	else
+		repo_config = NULL;
 
 	current_parsing_scope = CONFIG_SCOPE_SYSTEM;
 	if (git_config_system() && !access_or_die(git_etc_gitconfig(), R_OK, 0))
@@ -1530,13 +1565,14 @@
 
 int git_config_with_options(config_fn_t fn, void *data,
 			    struct git_config_source *config_source,
-			    int respect_includes)
+			    const struct config_options *opts)
 {
 	struct config_include_data inc = CONFIG_INCLUDE_INIT;
 
-	if (respect_includes) {
+	if (opts->respect_includes) {
 		inc.fn = fn;
 		inc.data = data;
+		inc.opts = opts;
 		fn = git_config_include;
 		data = &inc;
 	}
@@ -1552,12 +1588,15 @@
 	else if (config_source && config_source->blob)
 		return git_config_from_blob_ref(fn, config_source->blob, data);
 
-	return do_git_config_sequence(fn, data);
+	return do_git_config_sequence(opts, fn, data);
 }
 
 static void git_config_raw(config_fn_t fn, void *data)
 {
-	if (git_config_with_options(fn, data, NULL, 1) < 0)
+	struct config_options opts = {0};
+
+	opts.respect_includes = 1;
+	if (git_config_with_options(fn, data, NULL, &opts) < 0)
 		/*
 		 * git_config_with_options() normally returns only
 		 * zero, as most errors are fatal, and
@@ -1597,10 +1636,13 @@
 
 void read_early_config(config_fn_t cb, void *data)
 {
+	struct config_options opts = {0};
 	struct strbuf buf = STRBUF_INIT;
 
-	git_config_with_options(cb, data, NULL, 1);
+	opts.respect_includes = 1;
 
+	if (have_git_dir())
+		opts.git_dir = get_git_dir();
 	/*
 	 * When setup_git_directory() was not yet asked to discover the
 	 * GIT_DIR, we ask discover_git_directory() to figure out whether there
@@ -1609,14 +1651,11 @@
 	 * notably, the current working directory is still the same after the
 	 * call).
 	 */
-	if (!have_git_dir() && discover_git_directory(&buf)) {
-		struct git_config_source repo_config;
+	else if (discover_git_directory(&buf))
+		opts.git_dir = buf.buf;
 
-		memset(&repo_config, 0, sizeof(repo_config));
-		strbuf_addstr(&buf, "/config");
-		repo_config.file = buf.buf;
-		git_config_with_options(cb, data, &repo_config, 1);
-	}
+	git_config_with_options(cb, data, NULL, &opts);
+
 	strbuf_release(&buf);
 }
 
diff --git a/connect.c b/connect.c
index 7d65c1c..cd21a1b 100644
--- a/connect.c
+++ b/connect.c
@@ -111,8 +111,8 @@
  */
 struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 			      struct ref **list, unsigned int flags,
-			      struct sha1_array *extra_have,
-			      struct sha1_array *shallow_points)
+			      struct oid_array *extra_have,
+			      struct oid_array *shallow_points)
 {
 	struct ref **orig_list = list;
 
@@ -153,7 +153,7 @@
 				die("protocol error: expected shallow sha-1, got '%s'", arg);
 			if (!shallow_points)
 				die("repository on the other end cannot be shallow");
-			sha1_array_append(shallow_points, old_oid.hash);
+			oid_array_append(shallow_points, &old_oid);
 			continue;
 		}
 
@@ -169,7 +169,7 @@
 		}
 
 		if (extra_have && !strcmp(name, ".have")) {
-			sha1_array_append(extra_have, old_oid.hash);
+			oid_array_append(extra_have, &old_oid);
 			continue;
 		}
 
@@ -730,7 +730,7 @@
 		const char **ssh_argv;
 
 		p = xstrdup(ssh_command);
-		if (split_cmdline(p, &ssh_argv)) {
+		if (split_cmdline(p, &ssh_argv) > 0) {
 			variant = basename((char *)ssh_argv[0]);
 			/*
 			 * At this point, variant points into the buffer
@@ -738,8 +738,10 @@
 			 * any longer.
 			 */
 			free(ssh_argv);
-		} else
+		} else {
+			free(p);
 			return;
+		}
 	}
 
 	if (!strcasecmp(variant, "plink") ||
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index fc32286..af65899 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -28,6 +28,14 @@
 # completion style.  For example '!f() { : git commit ; ... }; f' will
 # tell the completion to use commit completion.  This also works with aliases
 # of form "!sh -c '...'".  For example, "!sh -c ': git commit ; ... '".
+#
+# You can set the following environment variables to influence the behavior of
+# the completion routines:
+#
+#   GIT_COMPLETION_CHECKOUT_NO_GUESS
+#
+#     When set to "1", do not include "DWIM" suggestions in git-checkout
+#     completion (e.g., completing "foo" when "origin/foo" exists).
 
 case "$COMP_WORDBREAKS" in
 *:*) : great ;;
@@ -213,6 +221,20 @@
 }
 fi
 
+# Fills the COMPREPLY array with prefiltered words without any additional
+# processing.
+# Callers must take care of providing only words that match the current word
+# to be completed and adding any prefix and/or suffix (trailing space!), if
+# necessary.
+# 1: List of newline-separated matching completion words, complete with
+#    prefix and suffix.
+__gitcomp_direct ()
+{
+	local IFS=$'\n'
+
+	COMPREPLY=($1)
+}
+
 __gitcompappend ()
 {
 	local x i=${#COMPREPLY[@]}
@@ -338,14 +360,27 @@
 	done | sort | uniq
 }
 
+# Lists branches from the local repository.
+# 1: A prefix to be added to each listed branch (optional).
+# 2: List only branches matching this word (optional; list all branches if
+#    unset or empty).
+# 3: A suffix to be appended to each listed branch (optional).
 __git_heads ()
 {
-	__git for-each-ref --format='%(refname:short)' refs/heads
+	local pfx="${1-}" cur_="${2-}" sfx="${3-}"
+
+	__git for-each-ref --format="${pfx//\%/%%}%(refname:strip=2)$sfx" \
+			"refs/heads/$cur_*" "refs/heads/$cur_*/**"
 }
 
+# Lists tags from the local repository.
+# Accepts the same positional parameters as __git_heads() above.
 __git_tags ()
 {
-	__git for-each-ref --format='%(refname:short)' refs/tags
+	local pfx="${1-}" cur_="${2-}" sfx="${3-}"
+
+	__git for-each-ref --format="${pfx//\%/%%}%(refname:strip=2)$sfx" \
+			"refs/tags/$cur_*" "refs/tags/$cur_*/**"
 }
 
 # Lists refs from the local (by default) or from a remote repository.
@@ -354,11 +389,21 @@
 #    Can be the name of a configured remote, a path, or a URL.
 # 2: In addition to local refs, list unique branches from refs/remotes/ for
 #    'git checkout's tracking DWIMery (optional; ignored, if set but empty).
+# 3: A prefix to be added to each listed ref (optional).
+# 4: List only refs matching this word (optional; list all refs if unset or
+#    empty).
+# 5: A suffix to be appended to each listed ref (optional; ignored, if set
+#    but empty).
+#
+# Use __git_complete_refs() instead.
 __git_refs ()
 {
 	local i hash dir track="${2-}"
 	local list_refs_from=path remote="${1-}"
-	local format refs pfx
+	local format refs
+	local pfx="${3-}" cur_="${4-$cur}" sfx="${5-}"
+	local match="${4-}"
+	local fer_pfx="${pfx//\%/%%}" # "escape" for-each-ref format specifiers
 
 	__git_find_repo_path
 	dir="$__git_repo_path"
@@ -382,63 +427,78 @@
 	fi
 
 	if [ "$list_refs_from" = path ]; then
-		case "$cur" in
+		if [[ "$cur_" == ^* ]]; then
+			pfx="$pfx^"
+			fer_pfx="$fer_pfx^"
+			cur_=${cur_#^}
+			match=${match#^}
+		fi
+		case "$cur_" in
 		refs|refs/*)
 			format="refname"
-			refs="${cur%/*}"
+			refs=("$match*" "$match*/**")
 			track=""
 			;;
 		*)
-			[[ "$cur" == ^* ]] && pfx="^"
 			for i in HEAD FETCH_HEAD ORIG_HEAD MERGE_HEAD; do
-				if [ -e "$dir/$i" ]; then echo $pfx$i; fi
+				case "$i" in
+				$match*)
+					if [ -e "$dir/$i" ]; then
+						echo "$pfx$i$sfx"
+					fi
+					;;
+				esac
 			done
-			format="refname:short"
-			refs="refs/tags refs/heads refs/remotes"
+			format="refname:strip=2"
+			refs=("refs/tags/$match*" "refs/tags/$match*/**"
+				"refs/heads/$match*" "refs/heads/$match*/**"
+				"refs/remotes/$match*" "refs/remotes/$match*/**")
 			;;
 		esac
-		__git_dir="$dir" __git for-each-ref --format="$pfx%($format)" \
-			$refs
+		__git_dir="$dir" __git for-each-ref --format="$fer_pfx%($format)$sfx" \
+			"${refs[@]}"
 		if [ -n "$track" ]; then
 			# employ the heuristic used by git checkout
 			# Try to find a remote branch that matches the completion word
 			# but only output if the branch name is unique
-			local ref entry
-			__git for-each-ref --shell --format="ref=%(refname:short)" \
-				"refs/remotes/" | \
-			while read -r entry; do
-				eval "$entry"
-				ref="${ref#*/}"
-				if [[ "$ref" == "$cur"* ]]; then
-					echo "$ref"
-				fi
-			done | sort | uniq -u
+			__git for-each-ref --format="$fer_pfx%(refname:strip=3)$sfx" \
+				--sort="refname:strip=3" \
+				"refs/remotes/*/$match*" "refs/remotes/*/$match*/**" | \
+			uniq -u
 		fi
 		return
 	fi
-	case "$cur" in
+	case "$cur_" in
 	refs|refs/*)
-		__git ls-remote "$remote" "$cur*" | \
+		__git ls-remote "$remote" "$match*" | \
 		while read -r hash i; do
 			case "$i" in
 			*^{}) ;;
-			*) echo "$i" ;;
+			*) echo "$pfx$i$sfx" ;;
 			esac
 		done
 		;;
 	*)
 		if [ "$list_refs_from" = remote ]; then
-			echo "HEAD"
-			__git for-each-ref --format="%(refname:short)" \
-				"refs/remotes/$remote/" | sed -e "s#^$remote/##"
+			case "HEAD" in
+			$match*)	echo "${pfx}HEAD$sfx" ;;
+			esac
+			__git for-each-ref --format="$fer_pfx%(refname:strip=3)$sfx" \
+				"refs/remotes/$remote/$match*" \
+				"refs/remotes/$remote/$match*/**"
 		else
-			__git ls-remote "$remote" HEAD \
-				"refs/tags/*" "refs/heads/*" "refs/remotes/*" |
+			local query_symref
+			case "HEAD" in
+			$match*)	query_symref="HEAD" ;;
+			esac
+			__git ls-remote "$remote" $query_symref \
+				"refs/tags/$match*" "refs/heads/$match*" \
+				"refs/remotes/$match*" |
 			while read -r hash i; do
 				case "$i" in
 				*^{})	;;
-				refs/*)	echo "${i#refs/*/}" ;;
-				*)	echo "$i" ;;  # symbolic refs
+				refs/*)	echo "$pfx${i#refs/*/}$sfx" ;;
+				*)	echo "$pfx$i$sfx" ;;  # symbolic refs
 				esac
 			done
 		fi
@@ -446,7 +506,38 @@
 	esac
 }
 
+# Completes refs, short and long, local and remote, symbolic and pseudo.
+#
+# Usage: __git_complete_refs [<option>]...
+# --remote=<remote>: The remote to list refs from, can be the name of a
+#                    configured remote, a path, or a URL.
+# --track: List unique remote branches for 'git checkout's tracking DWIMery.
+# --pfx=<prefix>: A prefix to be added to each ref.
+# --cur=<word>: The current ref to be completed.  Defaults to the current
+#               word to be completed.
+# --sfx=<suffix>: A suffix to be appended to each ref instead of the default
+#                 space.
+__git_complete_refs ()
+{
+	local remote track pfx cur_="$cur" sfx=" "
+
+	while test $# != 0; do
+		case "$1" in
+		--remote=*)	remote="${1##--remote=}" ;;
+		--track)	track="yes" ;;
+		--pfx=*)	pfx="${1##--pfx=}" ;;
+		--cur=*)	cur_="${1##--cur=}" ;;
+		--sfx=*)	sfx="${1##--sfx=}" ;;
+		*)		return 1 ;;
+		esac
+		shift
+	done
+
+	__gitcomp_direct "$(__git_refs "$remote" "$track" "$pfx" "$cur_" "$sfx")"
+}
+
 # __git_refs2 requires 1 argument (to pass to __git_refs)
+# Deprecated: use __git_complete_fetch_refspecs() instead.
 __git_refs2 ()
 {
 	local i
@@ -455,6 +546,24 @@
 	done
 }
 
+# Completes refspecs for fetching from a remote repository.
+# 1: The remote repository.
+# 2: A prefix to be added to each listed refspec (optional).
+# 3: The ref to be completed as a refspec instead of the current word to be
+#    completed (optional)
+# 4: A suffix to be appended to each listed refspec instead of the default
+#    space (optional).
+__git_complete_fetch_refspecs ()
+{
+	local i remote="$1" pfx="${2-}" cur_="${3-$cur}" sfx="${4- }"
+
+	__gitcomp_direct "$(
+		for i in $(__git_refs "$remote" "" "" "$cur_") ; do
+			echo "$pfx$i:$i$sfx"
+		done
+		)"
+}
+
 # __git_refs_remotes requires 1 argument (to pass to ls-remote)
 __git_refs_remotes ()
 {
@@ -554,15 +663,15 @@
 	*...*)
 		pfx="${cur_%...*}..."
 		cur_="${cur_#*...}"
-		__gitcomp_nl "$(__git_refs)" "$pfx" "$cur_"
+		__git_complete_refs --pfx="$pfx" --cur="$cur_"
 		;;
 	*..*)
 		pfx="${cur_%..*}.."
 		cur_="${cur_#*..}"
-		__gitcomp_nl "$(__git_refs)" "$pfx" "$cur_"
+		__git_complete_refs --pfx="$pfx" --cur="$cur_"
 		;;
 	*)
-		__gitcomp_nl "$(__git_refs)"
+		__git_complete_refs
 		;;
 	esac
 }
@@ -608,6 +717,7 @@
 		i="${words[c]}"
 		case "$i" in
 		--mirror) [ "$cmd" = "push" ] && no_complete_refspec=1 ;;
+		-d|--delete) [ "$cmd" = "push" ] && lhs=0 ;;
 		--all)
 			case "$cmd" in
 			push) no_complete_refspec=1 ;;
@@ -647,23 +757,23 @@
 	case "$cmd" in
 	fetch)
 		if [ $lhs = 1 ]; then
-			__gitcomp_nl "$(__git_refs2 "$remote")" "$pfx" "$cur_"
+			__git_complete_fetch_refspecs "$remote" "$pfx" "$cur_"
 		else
-			__gitcomp_nl "$(__git_refs)" "$pfx" "$cur_"
+			__git_complete_refs --pfx="$pfx" --cur="$cur_"
 		fi
 		;;
 	pull|remote)
 		if [ $lhs = 1 ]; then
-			__gitcomp_nl "$(__git_refs "$remote")" "$pfx" "$cur_"
+			__git_complete_refs --remote="$remote" --pfx="$pfx" --cur="$cur_"
 		else
-			__gitcomp_nl "$(__git_refs)" "$pfx" "$cur_"
+			__git_complete_refs --pfx="$pfx" --cur="$cur_"
 		fi
 		;;
 	push)
 		if [ $lhs = 1 ]; then
-			__gitcomp_nl "$(__git_refs)" "$pfx" "$cur_"
+			__git_complete_refs --pfx="$pfx" --cur="$cur_"
 		else
-			__gitcomp_nl "$(__git_refs "$remote")" "$pfx" "$cur_"
+			__git_complete_refs --remote="$remote" --pfx="$pfx" --cur="$cur_"
 		fi
 		;;
 	esac
@@ -1066,7 +1176,7 @@
 
 	case "$subcommand" in
 	bad|good|reset|skip|start)
-		__gitcomp_nl "$(__git_refs)"
+		__git_complete_refs
 		;;
 	*)
 		;;
@@ -1088,12 +1198,12 @@
 
 	case "$cur" in
 	--set-upstream-to=*)
-		__gitcomp_nl "$(__git_refs)" "" "${cur##--set-upstream-to=}"
+		__git_complete_refs --cur="${cur##--set-upstream-to=}"
 		;;
 	--*)
 		__gitcomp "
 			--color --no-color --verbose --abbrev= --no-abbrev
-			--track --no-track --contains --merged --no-merged
+			--track --no-track --contains --no-contains --merged --no-merged
 			--set-upstream-to= --edit-description --list
 			--unset-upstream --delete --move --remotes
 			--column --no-column --sort= --points-at
@@ -1101,9 +1211,9 @@
 		;;
 	*)
 		if [ $only_local_ref = "y" -a $has_r = "n" ]; then
-			__gitcomp_nl "$(__git_heads)"
+			__gitcomp_direct "$(__git_heads "" "$cur" " ")"
 		else
-			__gitcomp_nl "$(__git_refs)"
+			__git_complete_refs
 		fi
 		;;
 	esac
@@ -1146,18 +1256,19 @@
 	*)
 		# check if --track, --no-track, or --no-guess was specified
 		# if so, disable DWIM mode
-		local flags="--track --no-track --no-guess" track=1
-		if [ -n "$(__git_find_on_cmdline "$flags")" ]; then
-			track=''
+		local flags="--track --no-track --no-guess" track_opt="--track"
+		if [ "$GIT_COMPLETION_CHECKOUT_NO_GUESS" = "1" ] ||
+		   [ -n "$(__git_find_on_cmdline "$flags")" ]; then
+			track_opt=''
 		fi
-		__gitcomp_nl "$(__git_refs '' $track)"
+		__git_complete_refs $track_opt
 		;;
 	esac
 }
 
 _git_cherry ()
 {
-	__gitcomp_nl "$(__git_refs)"
+	__git_complete_refs
 }
 
 _git_cherry_pick ()
@@ -1172,7 +1283,7 @@
 		__gitcomp "--edit --no-commit --signoff --strategy= --mainline"
 		;;
 	*)
-		__gitcomp_nl "$(__git_refs)"
+		__git_complete_refs
 		;;
 	esac
 }
@@ -1224,7 +1335,7 @@
 {
 	case "$prev" in
 	-c|-C)
-		__gitcomp_nl "$(__git_refs)" "" "${cur}"
+		__git_complete_refs
 		return
 		;;
 	esac
@@ -1237,7 +1348,7 @@
 		;;
 	--reuse-message=*|--reedit-message=*|\
 	--fixup=*|--squash=*)
-		__gitcomp_nl "$(__git_refs)" "" "${cur#*=}"
+		__git_complete_refs --cur="${cur#*=}"
 		return
 		;;
 	--untracked-files=*)
@@ -1277,7 +1388,7 @@
 			"
 		return
 	esac
-	__gitcomp_nl "$(__git_refs)"
+	__git_complete_refs
 }
 
 __git_diff_algorithms="myers minimal patience histogram"
@@ -1428,8 +1539,43 @@
 	_gitk
 }
 
-__git_match_ctag() {
-	awk "/^${1//\//\\/}/ { print \$1 }" "$2"
+# Lists matching symbol names from a tag (as in ctags) file.
+# 1: List symbol names matching this word.
+# 2: The tag file to list symbol names from.
+# 3: A prefix to be added to each listed symbol name (optional).
+# 4: A suffix to be appended to each listed symbol name (optional).
+__git_match_ctag () {
+	awk -v pfx="${3-}" -v sfx="${4-}" "
+		/^${1//\//\\/}/ { print pfx \$1 sfx }
+		" "$2"
+}
+
+# Complete symbol names from a tag file.
+# Usage: __git_complete_symbol [<option>]...
+# --tags=<file>: The tag file to list symbol names from instead of the
+#                default "tags".
+# --pfx=<prefix>: A prefix to be added to each symbol name.
+# --cur=<word>: The current symbol name to be completed.  Defaults to
+#               the current word to be completed.
+# --sfx=<suffix>: A suffix to be appended to each symbol name instead
+#                 of the default space.
+__git_complete_symbol () {
+	local tags=tags pfx="" cur_="${cur-}" sfx=" "
+
+	while test $# != 0; do
+		case "$1" in
+		--tags=*)	tags="${1##--tags=}" ;;
+		--pfx=*)	pfx="${1##--pfx=}" ;;
+		--cur=*)	cur_="${1##--cur=}" ;;
+		--sfx=*)	sfx="${1##--sfx=}" ;;
+		*)		return 1 ;;
+		esac
+		shift
+	done
+
+	if test -r "$tags"; then
+		__gitcomp_direct "$(__git_match_ctag "$cur_" "$tags" "$pfx" "$sfx")"
+	fi
 }
 
 _git_grep ()
@@ -1459,14 +1605,11 @@
 
 	case "$cword,$prev" in
 	2,*|*,-*)
-		if test -r tags; then
-			__gitcomp_nl "$(__git_match_ctag "$cur" tags)"
-			return
-		fi
+		__git_complete_symbol && return
 		;;
 	esac
 
-	__gitcomp_nl "$(__git_refs)"
+	__git_complete_refs
 }
 
 _git_help ()
@@ -1573,6 +1716,19 @@
 	if [ -f "$__git_repo_path/MERGE_HEAD" ]; then
 		merge="--merge"
 	fi
+	case "$prev,$cur" in
+	-L,:*:*)
+		return	# fall back to Bash filename completion
+		;;
+	-L,:*)
+		__git_complete_symbol --cur="${cur#:}" --sfx=":"
+		return
+		;;
+	-G,*|-S,*)
+		__git_complete_symbol
+		return
+		;;
+	esac
 	case "$cur" in
 	--pretty=*|--format=*)
 		__gitcomp "$__git_log_pretty_formats $(__git_pretty_aliases)
@@ -1618,6 +1774,21 @@
 			"
 		return
 		;;
+	-L:*:*)
+		return	# fall back to Bash filename completion
+		;;
+	-L:*)
+		__git_complete_symbol --cur="${cur#-L:}" --sfx=":"
+		return
+		;;
+	-G*)
+		__git_complete_symbol --pfx="-G" --cur="${cur#-G}"
+		return
+		;;
+	-S*)
+		__git_complete_symbol --pfx="-S" --cur="${cur#-S}"
+		return
+		;;
 	esac
 	__git_complete_revlist
 }
@@ -1640,7 +1811,7 @@
 			--rerere-autoupdate --no-rerere-autoupdate --abort --continue"
 		return
 	esac
-	__gitcomp_nl "$(__git_refs)"
+	__git_complete_refs
 }
 
 _git_mergetool ()
@@ -1665,7 +1836,7 @@
 		return
 		;;
 	esac
-	__gitcomp_nl "$(__git_refs)"
+	__git_complete_refs
 }
 
 _git_mv ()
@@ -1703,7 +1874,7 @@
 	,*)
 		case "$prev" in
 		--ref)
-			__gitcomp_nl "$(__git_refs)"
+			__git_complete_refs
 			;;
 		*)
 			__gitcomp "$subcommands --ref"
@@ -1712,7 +1883,7 @@
 		;;
 	add,--reuse-message=*|append,--reuse-message=*|\
 	add,--reedit-message=*|append,--reedit-message=*)
-		__gitcomp_nl "$(__git_refs)" "" "${cur#*=}"
+		__git_complete_refs --cur="${cur#*=}"
 		;;
 	add,--*|append,--*)
 		__gitcomp '--file= --message= --reedit-message=
@@ -1731,7 +1902,7 @@
 		-m|-F)
 			;;
 		*)
-			__gitcomp_nl "$(__git_refs)"
+			__git_complete_refs
 			;;
 		esac
 		;;
@@ -1769,10 +1940,10 @@
 	--*=)
 		;;
 	*:*)
-		__gitcomp_nl "$(__git_refs)" "" "${cur_#*:}"
+		__git_complete_refs --cur="${cur_#*:}"
 		;;
 	*)
-		__gitcomp_nl "$(__git_refs)" "" "$cur_"
+		__git_complete_refs --cur="$cur_"
 		;;
 	esac
 }
@@ -1848,7 +2019,7 @@
 
 		return
 	esac
-	__gitcomp_nl "$(__git_refs)"
+	__git_complete_refs
 }
 
 _git_reflog ()
@@ -1859,7 +2030,7 @@
 	if [ -z "$subcommand" ]; then
 		__gitcomp "$subcommands"
 	else
-		__gitcomp_nl "$(__git_refs)"
+		__git_complete_refs
 	fi
 }
 
@@ -2005,7 +2176,7 @@
 		return
 		;;
 	branch.*.merge)
-		__gitcomp_nl "$(__git_refs)"
+		__git_complete_refs
 		return
 		;;
 	branch.*.rebase)
@@ -2109,7 +2280,7 @@
 		;;
 	branch.*)
 		local pfx="${cur%.*}." cur_="${cur#*.}"
-		__gitcomp_nl "$(__git_heads)" "$pfx" "$cur_" "."
+		__gitcomp_direct "$(__git_heads "$pfx" "$cur_" ".")"
 		__gitcomp_nl_append $'autosetupmerge\nautosetuprebase\n' "$pfx" "$cur_"
 		return
 		;;
@@ -2516,7 +2687,7 @@
 		return
 		;;
 	esac
-	__gitcomp_nl "$(__git_refs)"
+	__git_complete_refs
 }
 
 _git_rerere ()
@@ -2540,7 +2711,7 @@
 		return
 		;;
 	esac
-	__gitcomp_nl "$(__git_refs)"
+	__git_complete_refs
 }
 
 _git_revert ()
@@ -2559,7 +2730,7 @@
 		return
 		;;
 	esac
-	__gitcomp_nl "$(__git_refs)"
+	__git_complete_refs
 }
 
 _git_rm ()
@@ -2667,7 +2838,7 @@
 			;;
 		branch,*)
 			if [ $cword -eq 3 ]; then
-				__gitcomp_nl "$(__git_refs)";
+				__git_complete_refs
 			else
 				__gitcomp_nl "$(__git stash list \
 						| sed -n -e 's/:.*//p')"
@@ -2834,7 +3005,7 @@
 		i="${words[c]}"
 		case "$i" in
 		-d|-v)
-			__gitcomp_nl "$(__git_tags)"
+			__gitcomp_direct "$(__git_tags "" "$cur" " ")"
 			return
 			;;
 		-f)
@@ -2849,11 +3020,11 @@
 		;;
 	-*|tag)
 		if [ $f = 1 ]; then
-			__gitcomp_nl "$(__git_tags)"
+			__gitcomp_direct "$(__git_tags "" "$cur" " ")"
 		fi
 		;;
 	*)
-		__gitcomp_nl "$(__git_refs)"
+		__git_complete_refs
 		;;
 	esac
 
@@ -2862,7 +3033,7 @@
 		__gitcomp "
 			--list --delete --verify --annotate --message --file
 			--sign --cleanup --local-user --force --column --sort=
-			--contains --points-at --merged --no-merged --create-reflog
+			--contains --no-contains --points-at --merged --no-merged --create-reflog
 			"
 		;;
 	esac
@@ -3024,6 +3195,15 @@
 		esac
 	}
 
+	__gitcomp_direct ()
+	{
+		emulate -L zsh
+
+		local IFS=$'\n'
+		compset -P '*[=:]'
+		compadd -Q -- ${=1} && _ret=0
+	}
+
 	__gitcomp_nl ()
 	{
 		emulate -L zsh
diff --git a/contrib/completion/git-completion.zsh b/contrib/completion/git-completion.zsh
index e255413..c3521fb 100644
--- a/contrib/completion/git-completion.zsh
+++ b/contrib/completion/git-completion.zsh
@@ -67,6 +67,15 @@
 	esac
 }
 
+__gitcomp_direct ()
+{
+	emulate -L zsh
+
+	local IFS=$'\n'
+	compset -P '*[=:]'
+	compadd -Q -- ${=1} && _ret=0
+}
+
 __gitcomp_nl ()
 {
 	emulate -L zsh
diff --git a/contrib/git-resurrect.sh b/contrib/git-resurrect.sh
index d7e97bb..8c171dd 100755
--- a/contrib/git-resurrect.sh
+++ b/contrib/git-resurrect.sh
@@ -26,13 +26,13 @@
 . git-sh-setup
 
 search_reflog () {
-        sed -ne 's~^\([^ ]*\) .*\tcheckout: moving from '"$1"' .*~\1~p' \
+	sed -ne 's~^\([^ ]*\) .*	checkout: moving from '"$1"' .*~\1~p' \
                 < "$GIT_DIR"/logs/HEAD
 }
 
 search_reflog_merges () {
 	git rev-parse $(
-		sed -ne 's~^[^ ]* \([^ ]*\) .*\tmerge '"$1"':.*~\1^2~p' \
+		sed -ne 's~^[^ ]* \([^ ]*\) .*	merge '"$1"':.*~\1^2~p' \
 			< "$GIT_DIR"/logs/HEAD
 	)
 }
diff --git a/credential-cache.c b/credential-cache.c
index 3cbd420..91550bf 100644
--- a/credential-cache.c
+++ b/credential-cache.c
@@ -87,7 +87,7 @@
 {
 	struct stat sb;
 	char *old_dir, *socket;
-	old_dir = expand_user_path("~/.git-credential-cache");
+	old_dir = expand_user_path("~/.git-credential-cache", 0);
 	if (old_dir && !stat(old_dir, &sb) && S_ISDIR(sb.st_mode))
 		socket = xstrfmt("%s/socket", old_dir);
 	else
diff --git a/credential-store.c b/credential-store.c
index 55ca1b1..ac29542 100644
--- a/credential-store.c
+++ b/credential-store.c
@@ -168,7 +168,7 @@
 	if (file) {
 		string_list_append(&fns, file);
 	} else {
-		if ((file = expand_user_path("~/.git-credentials")))
+		if ((file = expand_user_path("~/.git-credentials", 0)))
 			string_list_append_nodup(&fns, file);
 		file = xdg_config_home("credentials");
 		if (file)
diff --git a/daemon.c b/daemon.c
index 473e6b6..ac7181a 100644
--- a/daemon.c
+++ b/daemon.c
@@ -4,10 +4,6 @@
 #include "strbuf.h"
 #include "string-list.h"
 
-#ifndef HOST_NAME_MAX
-#define HOST_NAME_MAX 256
-#endif
-
 #ifdef NO_INITGROUPS
 #define initgroups(x, y) (0) /* nothing */
 #endif
@@ -449,46 +445,42 @@
 	fclose(fp);
 }
 
-static int run_service_command(const char **argv)
+static int run_service_command(struct child_process *cld)
 {
-	struct child_process cld = CHILD_PROCESS_INIT;
-
-	cld.argv = argv;
-	cld.git_cmd = 1;
-	cld.err = -1;
-	if (start_command(&cld))
+	argv_array_push(&cld->args, ".");
+	cld->git_cmd = 1;
+	cld->err = -1;
+	if (start_command(cld))
 		return -1;
 
 	close(0);
 	close(1);
 
-	copy_to_log(cld.err);
+	copy_to_log(cld->err);
 
-	return finish_command(&cld);
+	return finish_command(cld);
 }
 
 static int upload_pack(void)
 {
-	/* Timeout as string */
-	char timeout_buf[64];
-	const char *argv[] = { "upload-pack", "--strict", NULL, ".", NULL };
-
-	argv[2] = timeout_buf;
-
-	snprintf(timeout_buf, sizeof timeout_buf, "--timeout=%u", timeout);
-	return run_service_command(argv);
+	struct child_process cld = CHILD_PROCESS_INIT;
+	argv_array_pushl(&cld.args, "upload-pack", "--strict", NULL);
+	argv_array_pushf(&cld.args, "--timeout=%u", timeout);
+	return run_service_command(&cld);
 }
 
 static int upload_archive(void)
 {
-	static const char *argv[] = { "upload-archive", ".", NULL };
-	return run_service_command(argv);
+	struct child_process cld = CHILD_PROCESS_INIT;
+	argv_array_push(&cld.args, "upload-archive");
+	return run_service_command(&cld);
 }
 
 static int receive_pack(void)
 {
-	static const char *argv[] = { "receive-pack", ".", NULL };
-	return run_service_command(argv);
+	struct child_process cld = CHILD_PROCESS_INIT;
+	argv_array_push(&cld.args, "receive-pack");
+	return run_service_command(&cld);
 }
 
 static struct daemon_service daemon_service[] = {
diff --git a/diff.c b/diff.c
index 58cb72d..74283d9 100644
--- a/diff.c
+++ b/diff.c
@@ -398,7 +398,7 @@
 	 */
 	const char *name;
 
-	char hex[GIT_SHA1_HEXSZ + 1];
+	char hex[GIT_MAX_HEXSZ + 1];
 	char mode[10];
 
 	/*
@@ -911,7 +911,7 @@
 /*
  * '--color-words' algorithm can be described as:
  *
- *   1. collect a the minus/plus lines of a diff hunk, divided into
+ *   1. collect the minus/plus lines of a diff hunk, divided into
  *      minus-lines and plus-lines;
  *
  *   2. break both minus-lines and plus-lines into words and
@@ -4219,7 +4219,7 @@
 	 * uniqueness across all objects (statistically speaking).
 	 */
 	if (abblen < GIT_SHA1_HEXSZ - 3) {
-		static char hex[GIT_SHA1_HEXSZ + 1];
+		static char hex[GIT_MAX_HEXSZ + 1];
 		if (len < abblen && abblen <= len + 2)
 			xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
 		else
@@ -4570,6 +4570,19 @@
 	data->patchlen += new_len;
 }
 
+static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
+{
+	git_SHA1_Update(ctx, str, strlen(str));
+}
+
+static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
+{
+	/* large enough for 2^32 in octal */
+	char buf[12];
+	int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
+	git_SHA1_Update(ctx, buf, len);
+}
+
 /* returns 0 upon success, and writes result into sha1 */
 static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1, int diff_header_only)
 {
@@ -4577,7 +4590,6 @@
 	int i;
 	git_SHA_CTX ctx;
 	struct patch_id_t data;
-	char buffer[PATH_MAX * 4 + 20];
 
 	git_SHA1_Init(&ctx);
 	memset(&data, 0, sizeof(struct patch_id_t));
@@ -4609,36 +4621,30 @@
 
 		len1 = remove_space(p->one->path, strlen(p->one->path));
 		len2 = remove_space(p->two->path, strlen(p->two->path));
-		if (p->one->mode == 0)
-			len1 = snprintf(buffer, sizeof(buffer),
-					"diff--gita/%.*sb/%.*s"
-					"newfilemode%06o"
-					"---/dev/null"
-					"+++b/%.*s",
-					len1, p->one->path,
-					len2, p->two->path,
-					p->two->mode,
-					len2, p->two->path);
-		else if (p->two->mode == 0)
-			len1 = snprintf(buffer, sizeof(buffer),
-					"diff--gita/%.*sb/%.*s"
-					"deletedfilemode%06o"
-					"---a/%.*s"
-					"+++/dev/null",
-					len1, p->one->path,
-					len2, p->two->path,
-					p->one->mode,
-					len1, p->one->path);
-		else
-			len1 = snprintf(buffer, sizeof(buffer),
-					"diff--gita/%.*sb/%.*s"
-					"---a/%.*s"
-					"+++b/%.*s",
-					len1, p->one->path,
-					len2, p->two->path,
-					len1, p->one->path,
-					len2, p->two->path);
-		git_SHA1_Update(&ctx, buffer, len1);
+		patch_id_add_string(&ctx, "diff--git");
+		patch_id_add_string(&ctx, "a/");
+		git_SHA1_Update(&ctx, p->one->path, len1);
+		patch_id_add_string(&ctx, "b/");
+		git_SHA1_Update(&ctx, p->two->path, len2);
+
+		if (p->one->mode == 0) {
+			patch_id_add_string(&ctx, "newfilemode");
+			patch_id_add_mode(&ctx, p->two->mode);
+			patch_id_add_string(&ctx, "---/dev/null");
+			patch_id_add_string(&ctx, "+++b/");
+			git_SHA1_Update(&ctx, p->two->path, len2);
+		} else if (p->two->mode == 0) {
+			patch_id_add_string(&ctx, "deletedfilemode");
+			patch_id_add_mode(&ctx, p->one->mode);
+			patch_id_add_string(&ctx, "---a/");
+			git_SHA1_Update(&ctx, p->one->path, len1);
+			patch_id_add_string(&ctx, "+++/dev/null");
+		} else {
+			patch_id_add_string(&ctx, "---a/");
+			git_SHA1_Update(&ctx, p->one->path, len1);
+			patch_id_add_string(&ctx, "+++b/");
+			git_SHA1_Update(&ctx, p->two->path, len2);
+		}
 
 		if (diff_header_only)
 			continue;
diff --git a/diff.h b/diff.h
index e9ccb38..5be1ee7 100644
--- a/diff.h
+++ b/diff.h
@@ -14,7 +14,7 @@
 struct strbuf;
 struct diff_filespec;
 struct userdiff_driver;
-struct sha1_array;
+struct oid_array;
 struct commit;
 struct combine_diff_path;
 
@@ -236,7 +236,7 @@
 extern void show_combined_diff(struct combine_diff_path *elem, int num_parent,
 			      int dense, struct rev_info *);
 
-extern void diff_tree_combined(const unsigned char *sha1, const struct sha1_array *parents, int dense, struct rev_info *rev);
+extern void diff_tree_combined(const unsigned char *sha1, const struct oid_array *parents, int dense, struct rev_info *rev);
 
 extern void diff_tree_combined_merge(const struct commit *commit, int dense, struct rev_info *rev);
 
diff --git a/environment.c b/environment.c
index 2fdba76..ff6e4f0 100644
--- a/environment.c
+++ b/environment.c
@@ -167,8 +167,11 @@
 	const char *replace_ref_base;
 
 	git_dir = getenv(GIT_DIR_ENVIRONMENT);
-	if (!git_dir)
+	if (!git_dir) {
+		if (!startup_info->have_repository)
+			die("BUG: setup_git_env called without repository");
 		git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
+	}
 	gitfile = read_gitfile(git_dir);
 	git_dir = xstrdup(gitfile ? gitfile : git_dir);
 	if (get_common_dir(&sb, git_dir))
@@ -274,7 +277,7 @@
 	return git_object_dir;
 }
 
-int odb_mkstemp(char *template, size_t limit, const char *pattern)
+int odb_mkstemp(struct strbuf *template, const char *pattern)
 {
 	int fd;
 	/*
@@ -282,18 +285,16 @@
 	 * restrictive except to remove write permission.
 	 */
 	int mode = 0444;
-	snprintf(template, limit, "%s/%s",
-		 get_object_directory(), pattern);
-	fd = git_mkstemp_mode(template, mode);
+	git_path_buf(template, "objects/%s", pattern);
+	fd = git_mkstemp_mode(template->buf, mode);
 	if (0 <= fd)
 		return fd;
 
 	/* slow path */
 	/* some mkstemp implementations erase template on failure */
-	snprintf(template, limit, "%s/%s",
-		 get_object_directory(), pattern);
-	safe_create_leading_directories(template);
-	return xmkstemp_mode(template, mode);
+	git_path_buf(template, "objects/%s", pattern);
+	safe_create_leading_directories(template->buf);
+	return xmkstemp_mode(template->buf, mode);
 }
 
 int odb_pack_keep(const char *name)
diff --git a/fast-import.c b/fast-import.c
index f6f416f..cf58f87 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -890,14 +890,15 @@
 
 static void start_packfile(void)
 {
-	static char tmp_file[PATH_MAX];
+	struct strbuf tmp_file = STRBUF_INIT;
 	struct packed_git *p;
 	struct pack_header hdr;
 	int pack_fd;
 
-	pack_fd = odb_mkstemp(tmp_file, sizeof(tmp_file),
-			      "pack/tmp_pack_XXXXXX");
-	FLEX_ALLOC_STR(p, pack_name, tmp_file);
+	pack_fd = odb_mkstemp(&tmp_file, "pack/tmp_pack_XXXXXX");
+	FLEX_ALLOC_STR(p, pack_name, tmp_file.buf);
+	strbuf_release(&tmp_file);
+
 	p->pack_fd = pack_fd;
 	p->do_not_close = 1;
 	pack_file = sha1fd(pack_fd, p->pack_name);
@@ -3201,7 +3202,7 @@
 {
 	if (!relative_marks_paths || is_absolute_path(path))
 		return xstrdup(path);
-	return xstrdup(git_path("info/fast-import/%s", path));
+	return git_pathdup("info/fast-import/%s", path);
 }
 
 static void option_import_marks(const char *marks,
diff --git a/fetch-pack.c b/fetch-pack.c
index d07d85c..afb8b05 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -276,6 +276,8 @@
 			return ACK;
 		}
 	}
+	if (skip_prefix(line, "ERR ", &arg))
+		die(_("remote error: %s"), arg);
 	die(_("git fetch-pack: expected ACK/NAK, got '%s'"), line);
 }
 
@@ -802,8 +804,8 @@
 		if (args->use_thin_pack)
 			argv_array_push(&cmd.args, "--fix-thin");
 		if (args->lock_pack || unpack_limit) {
-			char hostname[256];
-			if (gethostname(hostname, sizeof(hostname)))
+			char hostname[HOST_NAME_MAX + 1];
+			if (xgethostname(hostname, sizeof(hostname)))
 				xsnprintf(hostname, sizeof(hostname), "localhost");
 			argv_array_pushf(&cmd.args,
 					"--keep=fetch-pack %"PRIuMAX " on %s",
@@ -1015,7 +1017,7 @@
 			   struct ref **sought, int nr_sought,
 			   struct shallow_info *si)
 {
-	struct sha1_array ref = SHA1_ARRAY_INIT;
+	struct oid_array ref = OID_ARRAY_INIT;
 	int *status;
 	int i;
 
@@ -1038,18 +1040,18 @@
 		 * shallow points that exist in the pack (iow in repo
 		 * after get_pack() and reprepare_packed_git())
 		 */
-		struct sha1_array extra = SHA1_ARRAY_INIT;
-		unsigned char (*sha1)[20] = si->shallow->sha1;
+		struct oid_array extra = OID_ARRAY_INIT;
+		struct object_id *oid = si->shallow->oid;
 		for (i = 0; i < si->shallow->nr; i++)
-			if (has_sha1_file(sha1[i]))
-				sha1_array_append(&extra, sha1[i]);
+			if (has_object_file(&oid[i]))
+				oid_array_append(&extra, &oid[i]);
 		if (extra.nr) {
 			setup_alternate_shallow(&shallow_lock,
 						&alternate_shallow_file,
 						&extra);
 			commit_lock_file(&shallow_lock);
 		}
-		sha1_array_clear(&extra);
+		oid_array_clear(&extra);
 		return;
 	}
 
@@ -1060,7 +1062,7 @@
 	if (!si->nr_ours && !si->nr_theirs)
 		return;
 	for (i = 0; i < nr_sought; i++)
-		sha1_array_append(&ref, sought[i]->old_oid.hash);
+		oid_array_append(&ref, &sought[i]->old_oid);
 	si->ref = &ref;
 
 	if (args->update_shallow) {
@@ -1070,23 +1072,23 @@
 		 * shallow roots that are actually reachable from new
 		 * refs.
 		 */
-		struct sha1_array extra = SHA1_ARRAY_INIT;
-		unsigned char (*sha1)[20] = si->shallow->sha1;
+		struct oid_array extra = OID_ARRAY_INIT;
+		struct object_id *oid = si->shallow->oid;
 		assign_shallow_commits_to_refs(si, NULL, NULL);
 		if (!si->nr_ours && !si->nr_theirs) {
-			sha1_array_clear(&ref);
+			oid_array_clear(&ref);
 			return;
 		}
 		for (i = 0; i < si->nr_ours; i++)
-			sha1_array_append(&extra, sha1[si->ours[i]]);
+			oid_array_append(&extra, &oid[si->ours[i]]);
 		for (i = 0; i < si->nr_theirs; i++)
-			sha1_array_append(&extra, sha1[si->theirs[i]]);
+			oid_array_append(&extra, &oid[si->theirs[i]]);
 		setup_alternate_shallow(&shallow_lock,
 					&alternate_shallow_file,
 					&extra);
 		commit_lock_file(&shallow_lock);
-		sha1_array_clear(&extra);
-		sha1_array_clear(&ref);
+		oid_array_clear(&extra);
+		oid_array_clear(&ref);
 		return;
 	}
 
@@ -1102,7 +1104,7 @@
 				sought[i]->status = REF_STATUS_REJECT_SHALLOW;
 	}
 	free(status);
-	sha1_array_clear(&ref);
+	oid_array_clear(&ref);
 }
 
 struct ref *fetch_pack(struct fetch_pack_args *args,
@@ -1110,7 +1112,7 @@
 		       const struct ref *ref,
 		       const char *dest,
 		       struct ref **sought, int nr_sought,
-		       struct sha1_array *shallow,
+		       struct oid_array *shallow,
 		       char **pack_lockfile)
 {
 	struct ref *ref_cpy;
diff --git a/fetch-pack.h b/fetch-pack.h
index a2d46e6..b6aeb43 100644
--- a/fetch-pack.h
+++ b/fetch-pack.h
@@ -4,7 +4,7 @@
 #include "string-list.h"
 #include "run-command.h"
 
-struct sha1_array;
+struct oid_array;
 
 struct fetch_pack_args {
 	const char *uploadpack;
@@ -42,7 +42,7 @@
 		       const char *dest,
 		       struct ref **sought,
 		       int nr_sought,
-		       struct sha1_array *shallow,
+		       struct oid_array *shallow,
 		       char **pack_lockfile);
 
 /*
diff --git a/fsck.c b/fsck.c
index 9397927..e6152e4 100644
--- a/fsck.c
+++ b/fsck.c
@@ -132,10 +132,10 @@
 
 static void init_skiplist(struct fsck_options *options, const char *path)
 {
-	static struct sha1_array skiplist = SHA1_ARRAY_INIT;
+	static struct oid_array skiplist = OID_ARRAY_INIT;
 	int sorted, fd;
-	char buffer[41];
-	unsigned char sha1[20];
+	char buffer[GIT_MAX_HEXSZ + 1];
+	struct object_id oid;
 
 	if (options->skiplist)
 		sorted = options->skiplist->sorted;
@@ -148,17 +148,18 @@
 	if (fd < 0)
 		die("Could not open skip list: %s", path);
 	for (;;) {
+		const char *p;
 		int result = read_in_full(fd, buffer, sizeof(buffer));
 		if (result < 0)
 			die_errno("Could not read '%s'", path);
 		if (!result)
 			break;
-		if (get_sha1_hex(buffer, sha1) || buffer[40] != '\n')
+		if (parse_oid_hex(buffer, &oid, &p) || *p != '\n')
 			die("Invalid SHA-1: %s", buffer);
-		sha1_array_append(&skiplist, sha1);
+		oid_array_append(&skiplist, &oid);
 		if (sorted && skiplist.nr > 1 &&
-				hashcmp(skiplist.sha1[skiplist.nr - 2],
-					sha1) > 0)
+				oidcmp(&skiplist.oid[skiplist.nr - 2],
+				       &oid) > 0)
 			sorted = 0;
 	}
 	close(fd);
@@ -279,7 +280,7 @@
 		return 0;
 
 	if (options->skiplist && object &&
-			sha1_array_lookup(options->skiplist, object->oid.hash) >= 0)
+			oid_array_lookup(options->skiplist, &object->oid) >= 0)
 		return 0;
 
 	if (msg_type == FSCK_FATAL)
diff --git a/fsck.h b/fsck.h
index 1891c18..4525510 100644
--- a/fsck.h
+++ b/fsck.h
@@ -34,7 +34,7 @@
 	fsck_error error_func;
 	unsigned strict:1;
 	int *msg_type;
-	struct sha1_array *skiplist;
+	struct oid_array *skiplist;
 	struct decoration *object_names;
 };
 
diff --git a/git-add--interactive.perl b/git-add--interactive.perl
index 77b4ed5..709a5f6 100755
--- a/git-add--interactive.perl
+++ b/git-add--interactive.perl
@@ -1040,7 +1040,7 @@
 marked for applying."),
 	checkout_index => N__(
 "If the patch applies cleanly, the edited hunk will immediately be
-marked for discarding"),
+marked for discarding."),
 	checkout_head => N__(
 "If the patch applies cleanly, the edited hunk will immediately be
 marked for discarding."),
diff --git a/git-compat-util.h b/git-compat-util.h
index 8a4a3f8..bd04564 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -884,6 +884,12 @@
 __attribute__((format (printf, 3, 4)))
 extern int xsnprintf(char *dst, size_t max, const char *fmt, ...);
 
+#ifndef HOST_NAME_MAX
+#define HOST_NAME_MAX 256
+#endif
+
+extern int xgethostname(char *buf, size_t len);
+
 /* in ctype.c, for kwset users */
 extern const unsigned char tolower_trans_tbl[256];
 
diff --git a/git-p4.py b/git-p4.py
index eab319d..8d151da 100755
--- a/git-p4.py
+++ b/git-p4.py
@@ -160,17 +160,42 @@
     real_cmd = p4_build_cmd(c)
     return write_pipe(real_cmd, stdin)
 
-def read_pipe(c, ignore_error=False):
+def read_pipe_full(c):
+    """ Read output from  command. Returns a tuple
+        of the return status, stdout text and stderr
+        text.
+    """
     if verbose:
         sys.stderr.write('Reading pipe: %s\n' % str(c))
 
     expand = isinstance(c,basestring)
     p = subprocess.Popen(c, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=expand)
     (out, err) = p.communicate()
-    if p.returncode != 0 and not ignore_error:
-        die('Command failed: %s\nError: %s' % (str(c), err))
+    return (p.returncode, out, err)
+
+def read_pipe(c, ignore_error=False):
+    """ Read output from  command. Returns the output text on
+        success. On failure, terminates execution, unless
+        ignore_error is True, when it returns an empty string.
+    """
+    (retcode, out, err) = read_pipe_full(c)
+    if retcode != 0:
+        if ignore_error:
+            out = ""
+        else:
+            die('Command failed: %s\nError: %s' % (str(c), err))
     return out
 
+def read_pipe_text(c):
+    """ Read output from a command with trailing whitespace stripped.
+        On error, returns None.
+    """
+    (retcode, out, err) = read_pipe_full(c)
+    if retcode != 0:
+        return None
+    else:
+        return out.rstrip()
+
 def p4_read_pipe(c, ignore_error=False):
     real_cmd = p4_build_cmd(c)
     return read_pipe(real_cmd, ignore_error)
@@ -577,12 +602,7 @@
     return clientPath
 
 def currentGitBranch():
-    retcode = system(["git", "symbolic-ref", "-q", "HEAD"], ignore_error=True)
-    if retcode != 0:
-        # on a detached head
-        return None
-    else:
-        return read_pipe(["git", "name-rev", "HEAD"]).split(" ")[1].strip()
+    return read_pipe_text(["git", "symbolic-ref", "--short", "-q", "HEAD"])
 
 def isValidGitDir(path):
     return git_dir(path) != None
diff --git a/git-rebase.sh b/git-rebase.sh
index 48d7c5d..db1deed 100755
--- a/git-rebase.sh
+++ b/git-rebase.sh
@@ -34,6 +34,7 @@
 autosquash         move commits that begin with squash!/fixup! under -i
 committer-date-is-author-date! passed to 'git am'
 ignore-date!       passed to 'git am'
+signoff            passed to 'git am'
 whitespace=!       passed to 'git apply'
 ignore-whitespace! passed to 'git apply'
 C=!                passed to 'git apply'
@@ -321,7 +322,7 @@
 	--ignore-whitespace)
 		git_am_opt="$git_am_opt $1"
 		;;
-	--committer-date-is-author-date|--ignore-date)
+	--committer-date-is-author-date|--ignore-date|--signoff|--no-signoff)
 		git_am_opt="$git_am_opt $1"
 		force_rebase=t
 		;;
diff --git a/git-submodule.sh b/git-submodule.sh
index 136e26a..c0d0e9a 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -278,6 +278,20 @@
 	fi &&
 	git add --force .gitmodules ||
 	die "$(eval_gettext "Failed to register submodule '\$sm_path'")"
+
+	# NEEDSWORK: In a multi-working-tree world, this needs to be
+	# set in the per-worktree config.
+	if git config --get submodule.active >/dev/null
+	then
+		# If the submodule being adding isn't already covered by the
+		# current configured pathspec, set the submodule's active flag
+		if ! git submodule--helper is-active "$sm_path"
+		then
+			git config submodule."$sm_name".active "true"
+		fi
+	else
+		git config submodule."$sm_name".active "true"
+	fi
 }
 
 #
@@ -318,7 +332,7 @@
 		git submodule--helper list --prefix "$wt_prefix" ||
 		echo "#unmatched" $?
 	} |
-	while read mode sha1 stage sm_path
+	while read -r mode sha1 stage sm_path
 	do
 		die_if_unmatched "$mode" "$sha1"
 		if test -e "$sm_path"/.git
@@ -427,7 +441,7 @@
 		git submodule--helper list --prefix "$wt_prefix" "$@" ||
 		echo "#unmatched" $?
 	} |
-	while read mode sha1 stage sm_path
+	while read -r mode sha1 stage sm_path
 	do
 		die_if_unmatched "$mode" "$sha1"
 		name=$(git submodule--helper name "$sm_path") || exit
@@ -591,7 +605,7 @@
 		"$@" || echo "#unmatched" $?
 	} | {
 	err=
-	while read mode sha1 stage just_cloned sm_path
+	while read -r mode sha1 stage just_cloned sm_path
 	do
 		die_if_unmatched "$mode" "$sha1"
 
@@ -833,7 +847,7 @@
 	# Get modified modules cared by user
 	modules=$(git $diff_cmd $cached --ignore-submodules=dirty --raw $head -- "$@" |
 		sane_egrep '^:([0-7]* )?160000' |
-		while read mod_src mod_dst sha1_src sha1_dst status sm_path
+		while read -r mod_src mod_dst sha1_src sha1_dst status sm_path
 		do
 			# Always show modules deleted or type-changed (blob<->module)
 			if test "$status" = D || test "$status" = T
@@ -859,7 +873,7 @@
 	git $diff_cmd $cached --ignore-submodules=dirty --raw $head -- $modules |
 	sane_egrep '^:([0-7]* )?160000' |
 	cut -c2- |
-	while read mod_src mod_dst sha1_src sha1_dst status name
+	while read -r mod_src mod_dst sha1_src sha1_dst status name
 	do
 		if test -z "$cached" &&
 			test $sha1_dst = 0000000000000000000000000000000000000000
@@ -1006,18 +1020,17 @@
 		git submodule--helper list --prefix "$wt_prefix" "$@" ||
 		echo "#unmatched" $?
 	} |
-	while read mode sha1 stage sm_path
+	while read -r mode sha1 stage sm_path
 	do
 		die_if_unmatched "$mode" "$sha1"
 		name=$(git submodule--helper name "$sm_path") || exit
-		url=$(git config submodule."$name".url)
 		displaypath=$(git submodule--helper relative-path "$prefix$sm_path" "$wt_prefix")
 		if test "$stage" = U
 		then
 			say "U$sha1 $displaypath"
 			continue
 		fi
-		if test -z "$url" ||
+		if ! git submodule--helper is-active "$sm_path" ||
 		{
 			! test -d "$sm_path"/.git &&
 			! test -f "$sm_path"/.git
@@ -1087,9 +1100,16 @@
 		git submodule--helper list --prefix "$wt_prefix" "$@" ||
 		echo "#unmatched" $?
 	} |
-	while read mode sha1 stage sm_path
+	while read -r mode sha1 stage sm_path
 	do
 		die_if_unmatched "$mode" "$sha1"
+
+		# skip inactive submodules
+		if ! git submodule--helper is-active "$sm_path"
+		then
+			continue
+		fi
+
 		name=$(git submodule--helper name "$sm_path")
 		url=$(git config -f .gitmodules --get submodule."$name".url)
 
@@ -1112,27 +1132,24 @@
 			;;
 		esac
 
-		if git config "submodule.$name.url" >/dev/null 2>/dev/null
+		displaypath=$(git submodule--helper relative-path "$prefix$sm_path" "$wt_prefix")
+		say "$(eval_gettext "Synchronizing submodule url for '\$displaypath'")"
+		git config submodule."$name".url "$super_config_url"
+
+		if test -e "$sm_path"/.git
 		then
-			displaypath=$(git submodule--helper relative-path "$prefix$sm_path" "$wt_prefix")
-			say "$(eval_gettext "Synchronizing submodule url for '\$displaypath'")"
-			git config submodule."$name".url "$super_config_url"
+		(
+			sanitize_submodule_env
+			cd "$sm_path"
+			remote=$(get_default_remote)
+			git config remote."$remote".url "$sub_origin_url"
 
-			if test -e "$sm_path"/.git
+			if test -n "$recursive"
 			then
-			(
-				sanitize_submodule_env
-				cd "$sm_path"
-				remote=$(get_default_remote)
-				git config remote."$remote".url "$sub_origin_url"
-
-				if test -n "$recursive"
-				then
-					prefix="$prefix$sm_path/"
-					eval cmd_sync
-				fi
-			)
+				prefix="$prefix$sm_path/"
+				eval cmd_sync
 			fi
+		)
 		fi
 	done
 }
diff --git a/git.c b/git.c
index 33f52ac..8ff44f0 100644
--- a/git.c
+++ b/git.c
@@ -361,8 +361,6 @@
 	if (!help && get_super_prefix()) {
 		if (!(p->option & SUPPORT_SUPER_PREFIX))
 			die("%s doesn't support --super-prefix", p->cmd);
-		if (prefix)
-			die("can't use --super-prefix from a subdirectory");
 	}
 
 	if (!help && p->option & NEED_WORK_TREE)
diff --git a/grep.c b/grep.c
index 56ef0ec..47cee45 100644
--- a/grep.c
+++ b/grep.c
@@ -1171,7 +1171,7 @@
 	}
 	if (opt->linenum) {
 		char buf[32];
-		snprintf(buf, sizeof(buf), "%d", lno);
+		xsnprintf(buf, sizeof(buf), "%d", lno);
 		output_color(opt, buf, strlen(buf), opt->color_lineno);
 		output_sep(opt, sign);
 	}
@@ -1653,7 +1653,7 @@
 				     opt->color_filename);
 			output_sep(opt, ':');
 		}
-		snprintf(buf, sizeof(buf), "%u\n", count);
+		xsnprintf(buf, sizeof(buf), "%u\n", count);
 		opt->output(opt, buf, strlen(buf));
 		return 1;
 	}
diff --git a/hex.c b/hex.c
index eab7b62..28b4411 100644
--- a/hex.c
+++ b/hex.c
@@ -85,7 +85,7 @@
 char *sha1_to_hex(const unsigned char *sha1)
 {
 	static int bufno;
-	static char hexbuffer[4][GIT_SHA1_HEXSZ + 1];
+	static char hexbuffer[4][GIT_MAX_HEXSZ + 1];
 	bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
 	return sha1_to_hex_r(hexbuffer[bufno], sha1);
 }
diff --git a/http.c b/http.c
index 96d84bb..d2e11ec 100644
--- a/http.c
+++ b/http.c
@@ -19,7 +19,7 @@
 #endif
 int active_requests;
 int http_is_verbose;
-size_t http_post_buffer = 16 * LARGE_PACKET_MAX;
+ssize_t http_post_buffer = 16 * LARGE_PACKET_MAX;
 
 #if LIBCURL_VERSION_NUM >= 0x070a06
 #define LIBCURL_CAN_HANDLE_AUTH_ANY
@@ -331,7 +331,9 @@
 	}
 
 	if (!strcmp("http.postbuffer", var)) {
-		http_post_buffer = git_config_int(var, value);
+		http_post_buffer = git_config_ssize_t(var, value);
+		if (http_post_buffer < 0)
+			warning(_("negative value for http.postbuffer; defaulting to %d"), LARGE_PACKET_MAX);
 		if (http_post_buffer < LARGE_PACKET_MAX)
 			http_post_buffer = LARGE_PACKET_MAX;
 		return 0;
@@ -836,8 +838,14 @@
 		}
 	}
 
-	if (curl_http_proxy) {
-		curl_easy_setopt(result, CURLOPT_PROXY, curl_http_proxy);
+	if (curl_http_proxy && curl_http_proxy[0] == '\0') {
+		/*
+		 * Handle case with the empty http.proxy value here to keep
+		 * common code clean.
+		 * NB: empty option disables proxying at all.
+		 */
+		curl_easy_setopt(result, CURLOPT_PROXY, "");
+	} else if (curl_http_proxy) {
 #if LIBCURL_VERSION_NUM >= 0x071800
 		if (starts_with(curl_http_proxy, "socks5h"))
 			curl_easy_setopt(result,
@@ -861,6 +869,9 @@
 			strbuf_release(&url);
 		}
 
+		if (!proxy_auth.host)
+			die("Invalid proxy URL '%s'", curl_http_proxy);
+
 		curl_easy_setopt(result, CURLOPT_PROXY, proxy_auth.host);
 #if LIBCURL_VERSION_NUM >= 0x071304
 		var_override(&curl_no_proxy, getenv("NO_PROXY"));
@@ -1366,9 +1377,9 @@
 		 * FAILONERROR it is lost, so we can give only the numeric
 		 * status code.
 		 */
-		snprintf(curl_errorstr, sizeof(curl_errorstr),
-			 "The requested URL returned error: %ld",
-			 results->http_code);
+		xsnprintf(curl_errorstr, sizeof(curl_errorstr),
+			  "The requested URL returned error: %ld",
+			  results->http_code);
 	}
 
 	if (results->curl_result == CURLE_OK) {
@@ -1410,8 +1421,8 @@
 {
 	slot->results = results;
 	if (!start_active_slot(slot)) {
-		snprintf(curl_errorstr, sizeof(curl_errorstr),
-			 "failed to start HTTP request");
+		xsnprintf(curl_errorstr, sizeof(curl_errorstr),
+			  "failed to start HTTP request");
 		return HTTP_START_FAILED;
 	}
 
diff --git a/http.h b/http.h
index 02bccb7..f7bd3b2 100644
--- a/http.h
+++ b/http.h
@@ -111,7 +111,7 @@
 extern long int git_curl_ipresolve;
 extern int active_requests;
 extern int http_is_verbose;
-extern size_t http_post_buffer;
+extern ssize_t http_post_buffer;
 extern struct credential http_auth;
 
 extern char curl_errorstr[CURL_ERROR_SIZE];
diff --git a/ident.c b/ident.c
index c0364fe..bea871c 100644
--- a/ident.c
+++ b/ident.c
@@ -120,9 +120,9 @@
 
 static void add_domainname(struct strbuf *out, int *is_bogus)
 {
-	char buf[1024];
+	char buf[HOST_NAME_MAX + 1];
 
-	if (gethostname(buf, sizeof(buf))) {
+	if (xgethostname(buf, sizeof(buf))) {
 		warning_errno("cannot get host name");
 		strbuf_addstr(out, "(none)");
 		*is_bogus = 1;
diff --git a/imap-send.c b/imap-send.c
index 5c7e27a..8575916 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -964,7 +964,7 @@
 		int gai;
 		char portstr[6];
 
-		snprintf(portstr, sizeof(portstr), "%d", srvc->port);
+		xsnprintf(portstr, sizeof(portstr), "%d", srvc->port);
 
 		memset(&hints, 0, sizeof(hints));
 		hints.ai_socktype = SOCK_STREAM;
diff --git a/mailinfo.c b/mailinfo.c
index a489d9d..6803775 100644
--- a/mailinfo.c
+++ b/mailinfo.c
@@ -757,8 +757,13 @@
 	assert(!mi->filter_stage);
 
 	if (mi->header_stage) {
-		if (!line->len || (line->len == 1 && line->buf[0] == '\n'))
+		if (!line->len || (line->len == 1 && line->buf[0] == '\n')) {
+			if (mi->inbody_header_accum.len) {
+				flush_inbody_header_accum(mi);
+				mi->header_stage = 0;
+			}
 			return 0;
+		}
 	}
 
 	if (mi->use_inbody_headers && mi->header_stage) {
diff --git a/name-hash.c b/name-hash.c
index cac313c..39309ef 100644
--- a/name-hash.c
+++ b/name-hash.c
@@ -342,7 +342,9 @@
 	 * Scan forward in the index array for index entries having the same
 	 * path prefix (that are also in this directory).
 	 */
-	if (strncmp(istate->cache[k_start + 1]->name, prefix->buf, prefix->len) > 0)
+	if (k_start + 1 >= k_end)
+		k = k_end;
+	else if (strncmp(istate->cache[k_start + 1]->name, prefix->buf, prefix->len) > 0)
 		k = k_start + 1;
 	else if (strncmp(istate->cache[k_end - 1]->name, prefix->buf, prefix->len) == 0)
 		k = k_end;
diff --git a/notes-merge.c b/notes-merge.c
index 5998605..32caaaf 100644
--- a/notes-merge.c
+++ b/notes-merge.c
@@ -676,7 +676,7 @@
 	const char *msg = strstr(buffer, "\n\n");
 	int baselen;
 
-	strbuf_addstr(&path, git_path(NOTES_MERGE_WORKTREE));
+	git_path_buf(&path, NOTES_MERGE_WORKTREE);
 	if (o->verbosity >= 3)
 		printf("Committing notes in notes merge worktree at %s\n",
 			path.buf);
@@ -741,7 +741,7 @@
 	struct strbuf buf = STRBUF_INIT;
 	int ret;
 
-	strbuf_addstr(&buf, git_path(NOTES_MERGE_WORKTREE));
+	git_path_buf(&buf, NOTES_MERGE_WORKTREE);
 	if (o->verbosity >= 3)
 		printf("Removing notes merge worktree at %s/*\n", buf.buf);
 	ret = remove_dir_recursively(&buf, REMOVE_DIR_KEEP_TOPLEVEL);
diff --git a/notes.c b/notes.c
index 2bab961..542563b 100644
--- a/notes.c
+++ b/notes.c
@@ -153,8 +153,8 @@
  * How to consolidate an int_node:
  * If there are > 1 non-NULL entries, give up and return non-zero.
  * Otherwise replace the int_node at the given index in the given parent node
- * with the only entry (or a NULL entry if no entries) from the given tree,
- * and return 0.
+ * with the only NOTE entry (or a NULL entry if no entries) from the given
+ * tree, and return 0.
  */
 static int note_tree_consolidate(struct int_node *tree,
 	struct int_node *parent, unsigned char index)
@@ -173,6 +173,8 @@
 		}
 	}
 
+	if (p && (GET_PTR_TYPE(p) != PTR_TYPE_NOTE))
+		return -2;
 	/* replace tree with p in parent[index] */
 	parent->a[index] = p;
 	free(tree);
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index 9705596..e313f4f 100644
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -508,18 +508,16 @@
 			  const char *filename,
 			  uint16_t options)
 {
-	static char tmp_file[PATH_MAX];
 	static uint16_t default_version = 1;
 	static uint16_t flags = BITMAP_OPT_FULL_DAG;
+	struct strbuf tmp_file = STRBUF_INIT;
 	struct sha1file *f;
 
 	struct bitmap_disk_header header;
 
-	int fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_bitmap_XXXXXX");
+	int fd = odb_mkstemp(&tmp_file, "pack/tmp_bitmap_XXXXXX");
 
-	if (fd < 0)
-		die_errno("unable to create '%s'", tmp_file);
-	f = sha1fd(fd, tmp_file);
+	f = sha1fd(fd, tmp_file.buf);
 
 	memcpy(header.magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE));
 	header.version = htons(default_version);
@@ -539,9 +537,11 @@
 
 	sha1close(f, NULL, CSUM_FSYNC);
 
-	if (adjust_shared_perm(tmp_file))
+	if (adjust_shared_perm(tmp_file.buf))
 		die_errno("unable to make temporary bitmap file readable");
 
-	if (rename(tmp_file, filename))
+	if (rename(tmp_file.buf, filename))
 		die_errno("unable to rename temporary bitmap file to '%s'", filename);
+
+	strbuf_release(&tmp_file);
 }
diff --git a/pack-write.c b/pack-write.c
index c057513..fa97b72 100644
--- a/pack-write.c
+++ b/pack-write.c
@@ -71,15 +71,15 @@
 		f = sha1fd_check(index_name);
 	} else {
 		if (!index_name) {
-			static char tmp_file[PATH_MAX];
-			fd = odb_mkstemp(tmp_file, sizeof(tmp_file), "pack/tmp_idx_XXXXXX");
-			index_name = xstrdup(tmp_file);
+			struct strbuf tmp_file = STRBUF_INIT;
+			fd = odb_mkstemp(&tmp_file, "pack/tmp_idx_XXXXXX");
+			index_name = strbuf_detach(&tmp_file, NULL);
 		} else {
 			unlink(index_name);
 			fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
+			if (fd < 0)
+				die_errno("unable to create '%s'", index_name);
 		}
-		if (fd < 0)
-			die_errno("unable to create '%s'", index_name);
 		f = sha1fd(fd, index_name);
 	}
 
@@ -329,11 +329,11 @@
 
 struct sha1file *create_tmp_packfile(char **pack_tmp_name)
 {
-	char tmpname[PATH_MAX];
+	struct strbuf tmpname = STRBUF_INIT;
 	int fd;
 
-	fd = odb_mkstemp(tmpname, sizeof(tmpname), "pack/tmp_pack_XXXXXX");
-	*pack_tmp_name = xstrdup(tmpname);
+	fd = odb_mkstemp(&tmpname, "pack/tmp_pack_XXXXXX");
+	*pack_tmp_name = strbuf_detach(&tmpname, NULL);
 	return sha1fd(fd, *pack_tmp_name);
 }
 
diff --git a/parse-options-cb.c b/parse-options-cb.c
index b7d8f7d..7419780 100644
--- a/parse-options-cb.c
+++ b/parse-options-cb.c
@@ -96,17 +96,17 @@
 
 int parse_opt_object_name(const struct option *opt, const char *arg, int unset)
 {
-	unsigned char sha1[20];
+	struct object_id oid;
 
 	if (unset) {
-		sha1_array_clear(opt->value);
+		oid_array_clear(opt->value);
 		return 0;
 	}
 	if (!arg)
 		return -1;
-	if (get_sha1(arg, sha1))
+	if (get_oid(arg, &oid))
 		return error(_("malformed object name '%s'"), arg);
-	sha1_array_append(opt->value, sha1);
+	oid_array_append(opt->value, &oid);
 	return 0;
 }
 
diff --git a/parse-options.h b/parse-options.h
index dcd8a09..af71122 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -258,7 +258,9 @@
 	  PARSE_OPT_LASTARG_DEFAULT | flag, \
 	  parse_opt_commits, (intptr_t) "HEAD" \
 	}
-#define OPT_CONTAINS(v, h) _OPT_CONTAINS_OR_WITH("contains", v, h, 0)
-#define OPT_WITH(v, h) _OPT_CONTAINS_OR_WITH("with", v, h, PARSE_OPT_HIDDEN)
+#define OPT_CONTAINS(v, h) _OPT_CONTAINS_OR_WITH("contains", v, h, PARSE_OPT_NONEG)
+#define OPT_NO_CONTAINS(v, h) _OPT_CONTAINS_OR_WITH("no-contains", v, h, PARSE_OPT_NONEG)
+#define OPT_WITH(v, h) _OPT_CONTAINS_OR_WITH("with", v, h, PARSE_OPT_HIDDEN | PARSE_OPT_NONEG)
+#define OPT_WITHOUT(v, h) _OPT_CONTAINS_OR_WITH("without", v, h, PARSE_OPT_HIDDEN | PARSE_OPT_NONEG)
 
 #endif
diff --git a/patch-ids.c b/patch-ids.c
index ce285c2..fa8f11d 100644
--- a/patch-ids.c
+++ b/patch-ids.c
@@ -71,7 +71,7 @@
 			       struct commit *commit,
 			       struct patch_ids *ids)
 {
-	unsigned char header_only_patch_id[GIT_SHA1_RAWSZ];
+	unsigned char header_only_patch_id[GIT_MAX_RAWSZ];
 
 	patch->commit = commit;
 	if (commit_patch_id(commit, &ids->diffopts, header_only_patch_id, 1))
diff --git a/patch-ids.h b/patch-ids.h
index 0f34ea1..b9e5751 100644
--- a/patch-ids.h
+++ b/patch-ids.h
@@ -3,7 +3,7 @@
 
 struct patch_id {
 	struct hashmap_entry ent;
-	unsigned char patch_id[GIT_SHA1_RAWSZ];
+	unsigned char patch_id[GIT_MAX_RAWSZ];
 	struct commit *commit;
 };
 
diff --git a/path.c b/path.c
index 2224843..c1cb1cf 100644
--- a/path.c
+++ b/path.c
@@ -471,39 +471,19 @@
 }
 
 /* Returns 0 on success, negative on failure. */
-#define SUBMODULE_PATH_ERR_NOT_CONFIGURED -1
 static int do_submodule_path(struct strbuf *buf, const char *path,
 			     const char *fmt, va_list args)
 {
-	const char *git_dir;
 	struct strbuf git_submodule_common_dir = STRBUF_INIT;
 	struct strbuf git_submodule_dir = STRBUF_INIT;
-	const struct submodule *sub;
-	int err = 0;
+	int ret;
 
-	strbuf_addstr(buf, path);
-	strbuf_complete(buf, '/');
-	strbuf_addstr(buf, ".git");
+	ret = submodule_to_gitdir(&git_submodule_dir, path);
+	if (ret)
+		goto cleanup;
 
-	git_dir = read_gitfile(buf->buf);
-	if (git_dir) {
-		strbuf_reset(buf);
-		strbuf_addstr(buf, git_dir);
-	}
-	if (!is_git_directory(buf->buf)) {
-		gitmodules_config();
-		sub = submodule_from_path(null_sha1, path);
-		if (!sub) {
-			err = SUBMODULE_PATH_ERR_NOT_CONFIGURED;
-			goto cleanup;
-		}
-		strbuf_reset(buf);
-		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
-	}
-
-	strbuf_addch(buf, '/');
-	strbuf_addbuf(&git_submodule_dir, buf);
-
+	strbuf_complete(&git_submodule_dir, '/');
+	strbuf_addbuf(buf, &git_submodule_dir);
 	strbuf_vaddf(buf, fmt, args);
 
 	if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
@@ -514,8 +494,7 @@
 cleanup:
 	strbuf_release(&git_submodule_dir);
 	strbuf_release(&git_submodule_common_dir);
-
-	return err;
+	return ret;
 }
 
 char *git_pathdup_submodule(const char *path, const char *fmt, ...)
@@ -638,8 +617,10 @@
  * Return a string with ~ and ~user expanded via getpw*.  If buf != NULL,
  * then it is a newly allocated string. Returns NULL on getpw failure or
  * if path is NULL.
+ *
+ * If real_home is true, real_path($HOME) is used in the expansion.
  */
-char *expand_user_path(const char *path)
+char *expand_user_path(const char *path, int real_home)
 {
 	struct strbuf user_path = STRBUF_INIT;
 	const char *to_copy = path;
@@ -654,7 +635,10 @@
 			const char *home = getenv("HOME");
 			if (!home)
 				goto return_null;
-			strbuf_addstr(&user_path, home);
+			if (real_home)
+				strbuf_addstr(&user_path, real_path(home));
+			else
+				strbuf_addstr(&user_path, home);
 #ifdef GIT_WINDOWS_NATIVE
 			convert_slashes(user_path.buf);
 #endif
@@ -723,7 +707,7 @@
 		strbuf_add(&validated_path, path, len);
 
 		if (used_path.buf[0] == '~') {
-			char *newpath = expand_user_path(used_path.buf);
+			char *newpath = expand_user_path(used_path.buf, 0);
 			if (!newpath)
 				return NULL;
 			strbuf_attach(&used_path, newpath, strlen(newpath),
diff --git a/pathspec.c b/pathspec.c
index 303efda..50f76ff 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -505,7 +505,7 @@
 	 * original. Useful for passing to another command.
 	 */
 	if ((flags & PATHSPEC_PREFIX_ORIGIN) &&
-	    prefixlen && !get_literal_global()) {
+	    !get_literal_global()) {
 		struct strbuf sb = STRBUF_INIT;
 
 		/* Preserve the actual prefix length of each pattern */
@@ -724,7 +724,7 @@
 		free(pathspec->items[i].match);
 		free(pathspec->items[i].original);
 
-		for (j = 0; j < pathspec->items[j].attr_match_nr; j++)
+		for (j = 0; j < pathspec->items[i].attr_match_nr; j++)
 			free(pathspec->items[i].attr_match[j].value);
 		free(pathspec->items[i].attr_match);
 
diff --git a/po/de.po b/po/de.po
index e9c86f5..913db39 100644
--- a/po/de.po
+++ b/po/de.po
@@ -7530,7 +7530,19 @@
 msgid "git describe [<options>] --dirty"
 msgstr "git describe [<Optionen>] --dirty"
 
-#: builtin/describe.c:217
+#: builtin/describe.c:52
+msgid "head"
+msgstr "Branch"
+
+#: builtin/describe.c:52
+msgid "lightweight"
+msgstr "nicht-annotiert"
+
+#: builtin/describe.c:52
+msgid "annotated"
+msgstr "annotiert"
+
+#: builtin/describe.c:249
 #, c-format
 msgid "annotated tag %s not available"
 msgstr "annotiertes Tag %s ist nicht verfügbar"
diff --git a/prio-queue.c b/prio-queue.c
index 17252d2..fc3860f 100644
--- a/prio-queue.c
+++ b/prio-queue.c
@@ -21,7 +21,7 @@
 
 	if (queue->compare != NULL)
 		die("BUG: prio_queue_reverse() on non-LIFO queue");
-	for (i = 0; i <= (j = (queue->nr - 1) - i); i++)
+	for (i = 0; i < (j = (queue->nr - 1) - i); i++)
 		swap(queue, i, j);
 }
 
diff --git a/read-cache.c b/read-cache.c
index 008b335..0d0081a 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -887,9 +887,32 @@
 	return retval;
 }
 
+
+/*
+ * Like strcmp(), but also return the offset of the first change.
+ * If strings are equal, return the length.
+ */
+int strcmp_offset(const char *s1, const char *s2, size_t *first_change)
+{
+	size_t k;
+
+	if (!first_change)
+		return strcmp(s1, s2);
+
+	for (k = 0; s1[k] == s2[k]; k++)
+		if (s1[k] == '\0')
+			break;
+
+	*first_change = k;
+	return (unsigned char)s1[k] - (unsigned char)s2[k];
+}
+
 /*
  * Do we have another file with a pathname that is a proper
  * subset of the name we're trying to add?
+ *
+ * That is, is there another file in the index with a path
+ * that matches a sub-directory in the given entry?
  */
 static int has_dir_name(struct index_state *istate,
 			const struct cache_entry *ce, int pos, int ok_to_replace)
@@ -898,9 +921,51 @@
 	int stage = ce_stage(ce);
 	const char *name = ce->name;
 	const char *slash = name + ce_namelen(ce);
+	size_t len_eq_last;
+	int cmp_last = 0;
+
+	/*
+	 * We are frequently called during an iteration on a sorted
+	 * list of pathnames and while building a new index.  Therefore,
+	 * there is a high probability that this entry will eventually
+	 * be appended to the index, rather than inserted in the middle.
+	 * If we can confirm that, we can avoid binary searches on the
+	 * components of the pathname.
+	 *
+	 * Compare the entry's full path with the last path in the index.
+	 */
+	if (istate->cache_nr > 0) {
+		cmp_last = strcmp_offset(name,
+			istate->cache[istate->cache_nr - 1]->name,
+			&len_eq_last);
+		if (cmp_last > 0) {
+			if (len_eq_last == 0) {
+				/*
+				 * The entry sorts AFTER the last one in the
+				 * index and their paths have no common prefix,
+				 * so there cannot be a F/D conflict.
+				 */
+				return retval;
+			} else {
+				/*
+				 * The entry sorts AFTER the last one in the
+				 * index, but has a common prefix.  Fall through
+				 * to the loop below to disect the entry's path
+				 * and see where the difference is.
+				 */
+			}
+		} else if (cmp_last == 0) {
+			/*
+			 * The entry exactly matches the last one in the
+			 * index, but because of multiple stage and CE_REMOVE
+			 * items, we fall through and let the regular search
+			 * code handle it.
+			 */
+		}
+	}
 
 	for (;;) {
-		int len;
+		size_t len;
 
 		for (;;) {
 			if (*--slash == '/')
@@ -910,6 +975,67 @@
 		}
 		len = slash - name;
 
+		if (cmp_last > 0) {
+			/*
+			 * (len + 1) is a directory boundary (including
+			 * the trailing slash).  And since the loop is
+			 * decrementing "slash", the first iteration is
+			 * the longest directory prefix; subsequent
+			 * iterations consider parent directories.
+			 */
+
+			if (len + 1 <= len_eq_last) {
+				/*
+				 * The directory prefix (including the trailing
+				 * slash) also appears as a prefix in the last
+				 * entry, so the remainder cannot collide (because
+				 * strcmp said the whole path was greater).
+				 *
+				 * EQ: last: xxx/A
+				 *     this: xxx/B
+				 *
+				 * LT: last: xxx/file_A
+				 *     this: xxx/file_B
+				 */
+				return retval;
+			}
+
+			if (len > len_eq_last) {
+				/*
+				 * This part of the directory prefix (excluding
+				 * the trailing slash) is longer than the known
+				 * equal portions, so this sub-directory cannot
+				 * collide with a file.
+				 *
+				 * GT: last: xxxA
+				 *     this: xxxB/file
+				 */
+				return retval;
+			}
+
+			if (istate->cache_nr > 0 &&
+				ce_namelen(istate->cache[istate->cache_nr - 1]) > len) {
+				/*
+				 * The directory prefix lines up with part of
+				 * a longer file or directory name, but sorts
+				 * after it, so this sub-directory cannot
+				 * collide with a file.
+				 *
+				 * last: xxx/yy-file (because '-' sorts before '/')
+				 * this: xxx/yy/abc
+				 */
+				return retval;
+			}
+
+			/*
+			 * This is a possible collision. Fall through and
+			 * let the regular search code handle it.
+			 *
+			 * last: xxx
+			 * this: xxx/file
+			 */
+		}
+
 		pos = index_name_stage_pos(istate, name, len, stage);
 		if (pos >= 0) {
 			/*
@@ -1001,7 +1127,16 @@
 
 	if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
 		cache_tree_invalidate_path(istate, ce->name);
-	pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
+
+	/*
+	 * If this entry's path sorts after the last entry in the index,
+	 * we can avoid searching for it.
+	 */
+	if (istate->cache_nr > 0 &&
+		strcmp(ce->name, istate->cache[istate->cache_nr - 1]->name) > 0)
+		pos = -istate->cache_nr - 1;
+	else
+		pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
 
 	/* existing match? Just replace it. */
 	if (pos >= 0) {
@@ -1689,9 +1824,10 @@
  */
 static void freshen_shared_index(char *base_sha1_hex, int warn)
 {
-	const char *shared_index = git_path("sharedindex.%s", base_sha1_hex);
+	char *shared_index = git_pathdup("sharedindex.%s", base_sha1_hex);
 	if (!check_and_freshen_file(shared_index, 1) && warn)
 		warning("could not freshen shared index '%s'", shared_index);
+	free(shared_index);
 }
 
 int read_index_from(struct index_state *istate, const char *path)
@@ -2236,7 +2372,7 @@
 	if (!expiration)
 		return 0;
 	if (stat(shared_index_path, &st))
-		return error_errno(_("could not stat '%s"), shared_index_path);
+		return error_errno(_("could not stat '%s'"), shared_index_path);
 	if (st.st_mtime > expiration)
 		return 0;
 
diff --git a/ref-filter.c b/ref-filter.c
index 9c82b5b..3a64044 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -1487,6 +1487,7 @@
 	struct ref_array *array;
 	struct ref_filter *filter;
 	struct contains_cache contains_cache;
+	struct contains_cache no_contains_cache;
 };
 
 /*
@@ -1586,11 +1587,11 @@
 }
 
 static int commit_contains(struct ref_filter *filter, struct commit *commit,
-			   struct contains_cache *cache)
+			   struct commit_list *list, struct contains_cache *cache)
 {
 	if (filter->with_commit_tag_algo)
-		return contains_tag_algo(commit, filter->with_commit, cache) == CONTAINS_YES;
-	return is_descendant_of(commit, filter->with_commit);
+		return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
+	return is_descendant_of(commit, list);
 }
 
 /*
@@ -1677,22 +1678,22 @@
  * the need to parse the object via parse_object(). peel_ref() might be a
  * more efficient alternative to obtain the pointee.
  */
-static const unsigned char *match_points_at(struct sha1_array *points_at,
-					    const unsigned char *sha1,
-					    const char *refname)
+static const struct object_id *match_points_at(struct oid_array *points_at,
+					       const struct object_id *oid,
+					       const char *refname)
 {
-	const unsigned char *tagged_sha1 = NULL;
+	const struct object_id *tagged_oid = NULL;
 	struct object *obj;
 
-	if (sha1_array_lookup(points_at, sha1) >= 0)
-		return sha1;
-	obj = parse_object(sha1);
+	if (oid_array_lookup(points_at, oid) >= 0)
+		return oid;
+	obj = parse_object(oid->hash);
 	if (!obj)
 		die(_("malformed object at '%s'"), refname);
 	if (obj->type == OBJ_TAG)
-		tagged_sha1 = ((struct tag *)obj)->tagged->oid.hash;
-	if (tagged_sha1 && sha1_array_lookup(points_at, tagged_sha1) >= 0)
-		return tagged_sha1;
+		tagged_oid = &((struct tag *)obj)->tagged->oid;
+	if (tagged_oid && oid_array_lookup(points_at, tagged_oid) >= 0)
+		return tagged_oid;
 	return NULL;
 }
 
@@ -1772,7 +1773,7 @@
 	if (!filter_pattern_match(filter, refname))
 		return 0;
 
-	if (filter->points_at.nr && !match_points_at(&filter->points_at, oid->hash, refname))
+	if (filter->points_at.nr && !match_points_at(&filter->points_at, oid, refname))
 		return 0;
 
 	/*
@@ -1780,13 +1781,17 @@
 	 * obtain the commit using the 'oid' available and discard all
 	 * non-commits early. The actual filtering is done later.
 	 */
-	if (filter->merge_commit || filter->with_commit || filter->verbose) {
+	if (filter->merge_commit || filter->with_commit || filter->no_commit || filter->verbose) {
 		commit = lookup_commit_reference_gently(oid->hash, 1);
 		if (!commit)
 			return 0;
-		/* We perform the filtering for the '--contains' option */
+		/* We perform the filtering for the '--contains' option... */
 		if (filter->with_commit &&
-		    !commit_contains(filter, commit, &ref_cbdata->contains_cache))
+		    !commit_contains(filter, commit, filter->with_commit, &ref_cbdata->contains_cache))
+			return 0;
+		/* ...or for the `--no-contains' option */
+		if (filter->no_commit &&
+		    commit_contains(filter, commit, filter->no_commit, &ref_cbdata->no_contains_cache))
 			return 0;
 	}
 
@@ -1887,6 +1892,7 @@
 	filter->kind = type & FILTER_REFS_KIND_MASK;
 
 	init_contains_cache(&ref_cbdata.contains_cache);
+	init_contains_cache(&ref_cbdata.no_contains_cache);
 
 	/*  Simple per-ref filtering */
 	if (!filter->kind)
@@ -1911,6 +1917,7 @@
 	}
 
 	clear_contains_cache(&ref_cbdata.contains_cache);
+	clear_contains_cache(&ref_cbdata.no_contains_cache);
 
 	/*  Filters that need revision walking */
 	if (filter->merge_commit)
@@ -2084,8 +2091,17 @@
 {
 	struct ref_filter *rf = opt->value;
 	unsigned char sha1[20];
+	int no_merged = starts_with(opt->long_name, "no");
 
-	rf->merge = starts_with(opt->long_name, "no")
+	if (rf->merge) {
+		if (no_merged) {
+			return opterror(opt, "is incompatible with --merged", 0);
+		} else {
+			return opterror(opt, "is incompatible with --no-merged", 0);
+		}
+	}
+
+	rf->merge = no_merged
 		? REF_FILTER_MERGED_OMIT
 		: REF_FILTER_MERGED_INCLUDE;
 
diff --git a/ref-filter.h b/ref-filter.h
index e738c5d..c20167a 100644
--- a/ref-filter.h
+++ b/ref-filter.h
@@ -51,8 +51,9 @@
 
 struct ref_filter {
 	const char **name_patterns;
-	struct sha1_array points_at;
+	struct oid_array points_at;
 	struct commit_list *with_commit;
+	struct commit_list *no_commit;
 
 	enum {
 		REF_FILTER_MERGED_NONE = 0,
diff --git a/refs.c b/refs.c
index 0272e33..df75f8e 100644
--- a/refs.c
+++ b/refs.c
@@ -5,10 +5,12 @@
 #include "cache.h"
 #include "hashmap.h"
 #include "lockfile.h"
+#include "iterator.h"
 #include "refs.h"
 #include "refs/refs-internal.h"
 #include "object.h"
 #include "tag.h"
+#include "submodule.h"
 
 /*
  * List of all available backends
@@ -170,11 +172,23 @@
 	return 1;
 }
 
+char *refs_resolve_refdup(struct ref_store *refs,
+			  const char *refname, int resolve_flags,
+			  unsigned char *sha1, int *flags)
+{
+	const char *result;
+
+	result = refs_resolve_ref_unsafe(refs, refname, resolve_flags,
+					 sha1, flags);
+	return xstrdup_or_null(result);
+}
+
 char *resolve_refdup(const char *refname, int resolve_flags,
 		     unsigned char *sha1, int *flags)
 {
-	return xstrdup_or_null(resolve_ref_unsafe(refname, resolve_flags,
-						  sha1, flags));
+	return refs_resolve_refdup(get_main_ref_store(),
+				   refname, resolve_flags,
+				   sha1, flags);
 }
 
 /* The argument to filter_refs */
@@ -184,13 +198,20 @@
 	void *cb_data;
 };
 
-int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
+int refs_read_ref_full(struct ref_store *refs, const char *refname,
+		       int resolve_flags, unsigned char *sha1, int *flags)
 {
-	if (resolve_ref_unsafe(refname, resolve_flags, sha1, flags))
+	if (refs_resolve_ref_unsafe(refs, refname, resolve_flags, sha1, flags))
 		return 0;
 	return -1;
 }
 
+int read_ref_full(const char *refname, int resolve_flags, unsigned char *sha1, int *flags)
+{
+	return refs_read_ref_full(get_main_ref_store(), refname,
+				  resolve_flags, sha1, flags);
+}
+
 int read_ref(const char *refname, unsigned char *sha1)
 {
 	return read_ref_full(refname, RESOLVE_REF_READING, sha1, NULL);
@@ -285,34 +306,52 @@
 	for_each_rawref(warn_if_dangling_symref, &data);
 }
 
+int refs_for_each_tag_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
+{
+	return refs_for_each_ref_in(refs, "refs/tags/", fn, cb_data);
+}
+
 int for_each_tag_ref(each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in("refs/tags/", fn, cb_data);
+	return refs_for_each_tag_ref(get_main_ref_store(), fn, cb_data);
 }
 
 int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in_submodule(submodule, "refs/tags/", fn, cb_data);
+	return refs_for_each_tag_ref(get_submodule_ref_store(submodule),
+				     fn, cb_data);
+}
+
+int refs_for_each_branch_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
+{
+	return refs_for_each_ref_in(refs, "refs/heads/", fn, cb_data);
 }
 
 int for_each_branch_ref(each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in("refs/heads/", fn, cb_data);
+	return refs_for_each_branch_ref(get_main_ref_store(), fn, cb_data);
 }
 
 int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in_submodule(submodule, "refs/heads/", fn, cb_data);
+	return refs_for_each_branch_ref(get_submodule_ref_store(submodule),
+					fn, cb_data);
+}
+
+int refs_for_each_remote_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
+{
+	return refs_for_each_ref_in(refs, "refs/remotes/", fn, cb_data);
 }
 
 int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in("refs/remotes/", fn, cb_data);
+	return refs_for_each_remote_ref(get_main_ref_store(), fn, cb_data);
 }
 
 int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 {
-	return for_each_ref_in_submodule(submodule, "refs/remotes/", fn, cb_data);
+	return refs_for_each_remote_ref(get_submodule_ref_store(submodule),
+					fn, cb_data);
 }
 
 int head_ref_namespaced(each_ref_fn fn, void *cb_data)
@@ -429,29 +468,31 @@
 {
 	const char **p, *r;
 	int refs_found = 0;
+	struct strbuf fullref = STRBUF_INIT;
 
 	*ref = NULL;
 	for (p = ref_rev_parse_rules; *p; p++) {
-		char fullref[PATH_MAX];
 		unsigned char sha1_from_ref[20];
 		unsigned char *this_result;
 		int flag;
 
 		this_result = refs_found ? sha1_from_ref : sha1;
-		mksnpath(fullref, sizeof(fullref), *p, len, str);
-		r = resolve_ref_unsafe(fullref, RESOLVE_REF_READING,
+		strbuf_reset(&fullref);
+		strbuf_addf(&fullref, *p, len, str);
+		r = resolve_ref_unsafe(fullref.buf, RESOLVE_REF_READING,
 				       this_result, &flag);
 		if (r) {
 			if (!refs_found++)
 				*ref = xstrdup(r);
 			if (!warn_ambiguous_refs)
 				break;
-		} else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
-			warning("ignoring dangling symref %s.", fullref);
-		} else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
-			warning("ignoring broken ref %s.", fullref);
+		} else if ((flag & REF_ISSYMREF) && strcmp(fullref.buf, "HEAD")) {
+			warning("ignoring dangling symref %s.", fullref.buf);
+		} else if ((flag & REF_ISBROKEN) && strchr(fullref.buf, '/')) {
+			warning("ignoring broken ref %s.", fullref.buf);
 		}
 	}
+	strbuf_release(&fullref);
 	return refs_found;
 }
 
@@ -460,21 +501,22 @@
 	char *last_branch = substitute_branch_name(&str, &len);
 	const char **p;
 	int logs_found = 0;
+	struct strbuf path = STRBUF_INIT;
 
 	*log = NULL;
 	for (p = ref_rev_parse_rules; *p; p++) {
 		unsigned char hash[20];
-		char path[PATH_MAX];
 		const char *ref, *it;
 
-		mksnpath(path, sizeof(path), *p, len, str);
-		ref = resolve_ref_unsafe(path, RESOLVE_REF_READING,
+		strbuf_reset(&path);
+		strbuf_addf(&path, *p, len, str);
+		ref = resolve_ref_unsafe(path.buf, RESOLVE_REF_READING,
 					 hash, NULL);
 		if (!ref)
 			continue;
-		if (reflog_exists(path))
-			it = path;
-		else if (strcmp(ref, path) && reflog_exists(ref))
+		if (reflog_exists(path.buf))
+			it = path.buf;
+		else if (strcmp(ref, path.buf) && reflog_exists(ref))
 			it = ref;
 		else
 			continue;
@@ -485,6 +527,7 @@
 		if (!warn_ambiguous_refs)
 			break;
 	}
+	strbuf_release(&path);
 	free(last_branch);
 	return logs_found;
 }
@@ -592,16 +635,20 @@
 	return 0;
 }
 
-int delete_ref(const char *msg, const char *refname,
-	       const unsigned char *old_sha1, unsigned int flags)
+int refs_delete_ref(struct ref_store *refs, const char *msg,
+		    const char *refname,
+		    const unsigned char *old_sha1,
+		    unsigned int flags)
 {
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
 
-	if (ref_type(refname) == REF_TYPE_PSEUDOREF)
+	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
+		assert(refs == get_main_ref_store());
 		return delete_pseudoref(refname, old_sha1);
+	}
 
-	transaction = ref_transaction_begin(&err);
+	transaction = ref_store_transaction_begin(refs, &err);
 	if (!transaction ||
 	    ref_transaction_delete(transaction, refname, old_sha1,
 				   flags, msg, &err) ||
@@ -616,6 +663,13 @@
 	return 0;
 }
 
+int delete_ref(const char *msg, const char *refname,
+	       const unsigned char *old_sha1, unsigned int flags)
+{
+	return refs_delete_ref(get_main_ref_store(), msg, refname,
+			       old_sha1, flags);
+}
+
 int copy_reflog_msg(char *buf, const char *msg)
 {
 	char *cp = buf;
@@ -775,11 +829,20 @@
 	return 1;
 }
 
-struct ref_transaction *ref_transaction_begin(struct strbuf *err)
+struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
+						    struct strbuf *err)
 {
+	struct ref_transaction *tr;
 	assert(err);
 
-	return xcalloc(1, sizeof(struct ref_transaction));
+	tr = xcalloc(1, sizeof(struct ref_transaction));
+	tr->ref_store = refs;
+	return tr;
+}
+
+struct ref_transaction *ref_transaction_begin(struct strbuf *err)
+{
+	return ref_store_transaction_begin(get_main_ref_store(), err);
 }
 
 void ref_transaction_free(struct ref_transaction *transaction)
@@ -896,18 +959,20 @@
 		old_oid ? old_oid->hash : NULL, flags, onerr);
 }
 
-int update_ref(const char *msg, const char *refname,
-	       const unsigned char *new_sha1, const unsigned char *old_sha1,
-	       unsigned int flags, enum action_on_err onerr)
+int refs_update_ref(struct ref_store *refs, const char *msg,
+		    const char *refname, const unsigned char *new_sha1,
+		    const unsigned char *old_sha1, unsigned int flags,
+		    enum action_on_err onerr)
 {
 	struct ref_transaction *t = NULL;
 	struct strbuf err = STRBUF_INIT;
 	int ret = 0;
 
 	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
+		assert(refs == get_main_ref_store());
 		ret = write_pseudoref(refname, new_sha1, old_sha1, &err);
 	} else {
-		t = ref_transaction_begin(&err);
+		t = ref_store_transaction_begin(refs, &err);
 		if (!t ||
 		    ref_transaction_update(t, refname, new_sha1, old_sha1,
 					   flags, msg, &err) ||
@@ -938,12 +1003,22 @@
 	return 0;
 }
 
+int update_ref(const char *msg, const char *refname,
+	       const unsigned char *new_sha1,
+	       const unsigned char *old_sha1,
+	       unsigned int flags, enum action_on_err onerr)
+{
+	return refs_update_ref(get_main_ref_store(), msg, refname, new_sha1,
+			       old_sha1, flags, onerr);
+}
+
 char *shorten_unambiguous_ref(const char *refname, int strict)
 {
 	int i;
 	static char **scanf_fmts;
 	static int nr_rules;
 	char *short_name;
+	struct strbuf resolved_buf = STRBUF_INIT;
 
 	if (!nr_rules) {
 		/*
@@ -1002,7 +1077,6 @@
 		 */
 		for (j = 0; j < rules_to_fail; j++) {
 			const char *rule = ref_rev_parse_rules[j];
-			char refname[PATH_MAX];
 
 			/* skip matched rule */
 			if (i == j)
@@ -1013,9 +1087,10 @@
 			 * (with this previous rule) to a valid ref
 			 * read_ref() returns 0 on success
 			 */
-			mksnpath(refname, sizeof(refname),
-				 rule, short_name_len, short_name);
-			if (ref_exists(refname))
+			strbuf_reset(&resolved_buf);
+			strbuf_addf(&resolved_buf, rule,
+				    short_name_len, short_name);
+			if (ref_exists(resolved_buf.buf))
 				break;
 		}
 
@@ -1023,10 +1098,13 @@
 		 * short name is non-ambiguous if all previous rules
 		 * haven't resolved to a valid ref
 		 */
-		if (j == rules_to_fail)
+		if (j == rules_to_fail) {
+			strbuf_release(&resolved_buf);
 			return short_name;
+		}
 	}
 
+	strbuf_release(&resolved_buf);
 	free(short_name);
 	return xstrdup(refname);
 }
@@ -1119,14 +1197,17 @@
 	return NULL;
 }
 
-int rename_ref_available(const char *old_refname, const char *new_refname)
+int refs_rename_ref_available(struct ref_store *refs,
+			      const char *old_refname,
+			      const char *new_refname)
 {
 	struct string_list skip = STRING_LIST_INIT_NODUP;
 	struct strbuf err = STRBUF_INIT;
 	int ok;
 
 	string_list_insert(&skip, old_refname);
-	ok = !verify_refname_available(new_refname, NULL, &skip, &err);
+	ok = !refs_verify_refname_available(refs, new_refname,
+					    NULL, &skip, &err);
 	if (!ok)
 		error("%s", err.buf);
 
@@ -1158,6 +1239,18 @@
 	return head_ref_submodule(NULL, fn, cb_data);
 }
 
+struct ref_iterator *refs_ref_iterator_begin(
+		struct ref_store *refs,
+		const char *prefix, int trim, int flags)
+{
+	struct ref_iterator *iter;
+
+	iter = refs->be->iterator_begin(refs, prefix, flags);
+	iter = prefix_ref_iterator_begin(iter, prefix, trim);
+
+	return iter;
+}
+
 /*
  * Call fn for each reference in the specified submodule for which the
  * refname begins with prefix. If trim is non-zero, then trim that
@@ -1167,34 +1260,43 @@
  * non-zero value, stop the iteration and return that value;
  * otherwise, return 0.
  */
-static int do_for_each_ref(const char *submodule, const char *prefix,
+static int do_for_each_ref(struct ref_store *refs, const char *prefix,
 			   each_ref_fn fn, int trim, int flags, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(submodule);
 	struct ref_iterator *iter;
 
 	if (!refs)
 		return 0;
 
-	iter = refs->be->iterator_begin(refs, prefix, flags);
-	iter = prefix_ref_iterator_begin(iter, prefix, trim);
+	iter = refs_ref_iterator_begin(refs, prefix, trim, flags);
 
 	return do_for_each_ref_iterator(iter, fn, cb_data);
 }
 
+int refs_for_each_ref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
+{
+	return do_for_each_ref(refs, "", fn, 0, 0, cb_data);
+}
+
 int for_each_ref(each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
+	return refs_for_each_ref(get_main_ref_store(), fn, cb_data);
 }
 
 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
+	return refs_for_each_ref(get_submodule_ref_store(submodule), fn, cb_data);
+}
+
+int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
+			 each_ref_fn fn, void *cb_data)
+{
+	return do_for_each_ref(refs, prefix, fn, strlen(prefix), 0, cb_data);
 }
 
 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(NULL, prefix, fn, strlen(prefix), 0, cb_data);
+	return refs_for_each_ref_in(get_main_ref_store(), prefix, fn, cb_data);
 }
 
 int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
@@ -1203,19 +1305,23 @@
 
 	if (broken)
 		flag = DO_FOR_EACH_INCLUDE_BROKEN;
-	return do_for_each_ref(NULL, prefix, fn, 0, flag, cb_data);
+	return do_for_each_ref(get_main_ref_store(),
+			       prefix, fn, 0, flag, cb_data);
 }
 
 int for_each_ref_in_submodule(const char *submodule, const char *prefix,
-		each_ref_fn fn, void *cb_data)
+			      each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(submodule, prefix, fn, strlen(prefix), 0, cb_data);
+	return refs_for_each_ref_in(get_submodule_ref_store(submodule),
+				    prefix, fn, cb_data);
 }
 
 int for_each_replace_ref(each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(NULL, git_replace_ref_base, fn,
-			       strlen(git_replace_ref_base), 0, cb_data);
+	return do_for_each_ref(get_main_ref_store(),
+			       git_replace_ref_base, fn,
+			       strlen(git_replace_ref_base),
+			       0, cb_data);
 }
 
 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
@@ -1223,19 +1329,32 @@
 	struct strbuf buf = STRBUF_INIT;
 	int ret;
 	strbuf_addf(&buf, "%srefs/", get_git_namespace());
-	ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
+	ret = do_for_each_ref(get_main_ref_store(),
+			      buf.buf, fn, 0, 0, cb_data);
 	strbuf_release(&buf);
 	return ret;
 }
 
-int for_each_rawref(each_ref_fn fn, void *cb_data)
+int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 {
-	return do_for_each_ref(NULL, "", fn, 0,
+	return do_for_each_ref(refs, "", fn, 0,
 			       DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 }
 
+int for_each_rawref(each_ref_fn fn, void *cb_data)
+{
+	return refs_for_each_rawref(get_main_ref_store(), fn, cb_data);
+}
+
+int refs_read_raw_ref(struct ref_store *ref_store,
+		      const char *refname, unsigned char *sha1,
+		      struct strbuf *referent, unsigned int *type)
+{
+	return ref_store->be->read_raw_ref(ref_store, refname, sha1, referent, type);
+}
+
 /* This function needs to return a meaningful errno on failure */
-const char *resolve_ref_recursively(struct ref_store *refs,
+const char *refs_resolve_ref_unsafe(struct ref_store *refs,
 				    const char *refname,
 				    int resolve_flags,
 				    unsigned char *sha1, int *flags)
@@ -1270,8 +1389,8 @@
 	for (symref_count = 0; symref_count < SYMREF_MAXDEPTH; symref_count++) {
 		unsigned int read_flags = 0;
 
-		if (refs->be->read_raw_ref(refs, refname,
-					   sha1, &sb_refname, &read_flags)) {
+		if (refs_read_raw_ref(refs, refname,
+				      sha1, &sb_refname, &read_flags)) {
 			*flags |= read_flags;
 			if (errno != ENOENT || (resolve_flags & RESOLVE_REF_READING))
 				return NULL;
@@ -1314,7 +1433,7 @@
 /* backend functions */
 int refs_init_db(struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = get_main_ref_store();
 
 	return refs->be->init_db(refs, err);
 }
@@ -1322,7 +1441,7 @@
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       unsigned char *sha1, int *flags)
 {
-	return resolve_ref_recursively(get_ref_store(NULL), refname,
+	return refs_resolve_ref_unsafe(get_main_ref_store(), refname,
 				       resolve_flags, sha1, flags);
 }
 
@@ -1343,16 +1462,16 @@
 		/* We need to strip off one or more trailing slashes */
 		char *stripped = xmemdupz(submodule, len);
 
-		refs = get_ref_store(stripped);
+		refs = get_submodule_ref_store(stripped);
 		free(stripped);
 	} else {
-		refs = get_ref_store(submodule);
+		refs = get_submodule_ref_store(submodule);
 	}
 
 	if (!refs)
 		return -1;
 
-	if (!resolve_ref_recursively(refs, refname, 0, sha1, &flags) ||
+	if (!refs_resolve_ref_unsafe(refs, refname, 0, sha1, &flags) ||
 	    is_null_sha1(sha1))
 		return -1;
 	return 0;
@@ -1395,17 +1514,13 @@
 static struct hashmap submodule_ref_stores;
 
 /*
- * Return the ref_store instance for the specified submodule (or the
- * main repository if submodule is NULL). If that ref_store hasn't
- * been initialized yet, return NULL.
+ * Return the ref_store instance for the specified submodule. If that
+ * ref_store hasn't been initialized yet, return NULL.
  */
-static struct ref_store *lookup_ref_store(const char *submodule)
+static struct ref_store *lookup_submodule_ref_store(const char *submodule)
 {
 	struct submodule_hash_entry *entry;
 
-	if (!submodule)
-		return main_ref_store;
-
 	if (!submodule_ref_stores.tablesize)
 		/* It's initialized on demand in register_ref_store(). */
 		return NULL;
@@ -1416,33 +1531,11 @@
 }
 
 /*
- * Register the specified ref_store to be the one that should be used
- * for submodule (or the main repository if submodule is NULL). It is
- * a fatal error to call this function twice for the same submodule.
- */
-static void register_ref_store(struct ref_store *refs, const char *submodule)
-{
-	if (!submodule) {
-		if (main_ref_store)
-			die("BUG: main_ref_store initialized twice");
-
-		main_ref_store = refs;
-	} else {
-		if (!submodule_ref_stores.tablesize)
-			hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
-
-		if (hashmap_put(&submodule_ref_stores,
-				alloc_submodule_hash_entry(submodule, refs)))
-			die("BUG: ref_store for submodule '%s' initialized twice",
-			    submodule);
-	}
-}
-
-/*
  * Create, record, and return a ref_store instance for the specified
- * submodule (or the main repository if submodule is NULL).
+ * gitdir.
  */
-static struct ref_store *ref_store_init(const char *submodule)
+static struct ref_store *ref_store_init(const char *gitdir,
+					unsigned int flags)
 {
 	const char *be_name = "files";
 	struct ref_storage_be *be = find_ref_storage_backend(be_name);
@@ -1451,33 +1544,76 @@
 	if (!be)
 		die("BUG: reference backend %s is unknown", be_name);
 
-	refs = be->init(submodule);
-	register_ref_store(refs, submodule);
+	refs = be->init(gitdir, flags);
 	return refs;
 }
 
-struct ref_store *get_ref_store(const char *submodule)
+struct ref_store *get_main_ref_store(void)
 {
+	if (main_ref_store)
+		return main_ref_store;
+
+	main_ref_store = ref_store_init(get_git_dir(),
+					(REF_STORE_READ |
+					 REF_STORE_WRITE |
+					 REF_STORE_ODB |
+					 REF_STORE_MAIN));
+	return main_ref_store;
+}
+
+/*
+ * Register the specified ref_store to be the one that should be used
+ * for submodule. It is a fatal error to call this function twice for
+ * the same submodule.
+ */
+static void register_submodule_ref_store(struct ref_store *refs,
+					 const char *submodule)
+{
+	if (!submodule_ref_stores.tablesize)
+		hashmap_init(&submodule_ref_stores, submodule_hash_cmp, 0);
+
+	if (hashmap_put(&submodule_ref_stores,
+			alloc_submodule_hash_entry(submodule, refs)))
+		die("BUG: ref_store for submodule '%s' initialized twice",
+		    submodule);
+}
+
+struct ref_store *get_submodule_ref_store(const char *submodule)
+{
+	struct strbuf submodule_sb = STRBUF_INIT;
 	struct ref_store *refs;
+	int ret;
 
 	if (!submodule || !*submodule) {
-		refs = lookup_ref_store(NULL);
-
-		if (!refs)
-			refs = ref_store_init(NULL);
-	} else {
-		refs = lookup_ref_store(submodule);
-
-		if (!refs) {
-			struct strbuf submodule_sb = STRBUF_INIT;
-
-			strbuf_addstr(&submodule_sb, submodule);
-			if (is_nonbare_repository_dir(&submodule_sb))
-				refs = ref_store_init(submodule);
-			strbuf_release(&submodule_sb);
-		}
+		/*
+		 * FIXME: This case is ideally not allowed. But that
+		 * can't happen until we clean up all the callers.
+		 */
+		return get_main_ref_store();
 	}
 
+	refs = lookup_submodule_ref_store(submodule);
+	if (refs)
+		return refs;
+
+	strbuf_addstr(&submodule_sb, submodule);
+	ret = is_nonbare_repository_dir(&submodule_sb);
+	strbuf_release(&submodule_sb);
+	if (!ret)
+		return NULL;
+
+	ret = submodule_to_gitdir(&submodule_sb, submodule);
+	if (ret) {
+		strbuf_release(&submodule_sb);
+		return NULL;
+	}
+
+	/* assume that add_submodule_odb() has been called */
+	refs = ref_store_init(submodule_sb.buf,
+			      REF_STORE_READ | REF_STORE_ODB);
+	register_submodule_ref_store(refs, submodule);
+
+	strbuf_release(&submodule_sb);
 	return refs;
 }
 
@@ -1488,50 +1624,144 @@
 }
 
 /* backend functions */
-int pack_refs(unsigned int flags)
+int refs_pack_refs(struct ref_store *refs, unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
-
 	return refs->be->pack_refs(refs, flags);
 }
 
+int refs_peel_ref(struct ref_store *refs, const char *refname,
+		  unsigned char *sha1)
+{
+	return refs->be->peel_ref(refs, refname, sha1);
+}
+
 int peel_ref(const char *refname, unsigned char *sha1)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	return refs_peel_ref(get_main_ref_store(), refname, sha1);
+}
 
-	return refs->be->peel_ref(refs, refname, sha1);
+int refs_create_symref(struct ref_store *refs,
+		       const char *ref_target,
+		       const char *refs_heads_master,
+		       const char *logmsg)
+{
+	return refs->be->create_symref(refs, ref_target,
+				       refs_heads_master,
+				       logmsg);
 }
 
 int create_symref(const char *ref_target, const char *refs_heads_master,
 		  const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
-
-	return refs->be->create_symref(refs, ref_target, refs_heads_master,
-				       logmsg);
+	return refs_create_symref(get_main_ref_store(), ref_target,
+				  refs_heads_master, logmsg);
 }
 
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = transaction->ref_store;
+
+	if (getenv(GIT_QUARANTINE_ENVIRONMENT)) {
+		strbuf_addstr(err,
+			      _("ref updates forbidden inside quarantine environment"));
+		return -1;
+	}
 
 	return refs->be->transaction_commit(refs, transaction, err);
 }
 
-int verify_refname_available(const char *refname,
-			     const struct string_list *extra,
-			     const struct string_list *skip,
-			     struct strbuf *err)
+int refs_verify_refname_available(struct ref_store *refs,
+				  const char *refname,
+				  const struct string_list *extras,
+				  const struct string_list *skip,
+				  struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	const char *slash;
+	const char *extra_refname;
+	struct strbuf dirname = STRBUF_INIT;
+	struct strbuf referent = STRBUF_INIT;
+	struct object_id oid;
+	unsigned int type;
+	struct ref_iterator *iter;
+	int ok;
+	int ret = -1;
 
-	return refs->be->verify_refname_available(refs, refname, extra, skip, err);
+	/*
+	 * For the sake of comments in this function, suppose that
+	 * refname is "refs/foo/bar".
+	 */
+
+	assert(err);
+
+	strbuf_grow(&dirname, strlen(refname) + 1);
+	for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
+		/* Expand dirname to the new prefix, not including the trailing slash: */
+		strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
+
+		/*
+		 * We are still at a leading dir of the refname (e.g.,
+		 * "refs/foo"; if there is a reference with that name,
+		 * it is a conflict, *unless* it is in skip.
+		 */
+		if (skip && string_list_has_string(skip, dirname.buf))
+			continue;
+
+		if (!refs_read_raw_ref(refs, dirname.buf, oid.hash, &referent, &type)) {
+			strbuf_addf(err, "'%s' exists; cannot create '%s'",
+				    dirname.buf, refname);
+			goto cleanup;
+		}
+
+		if (extras && string_list_has_string(extras, dirname.buf)) {
+			strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
+				    refname, dirname.buf);
+			goto cleanup;
+		}
+	}
+
+	/*
+	 * We are at the leaf of our refname (e.g., "refs/foo/bar").
+	 * There is no point in searching for a reference with that
+	 * name, because a refname isn't considered to conflict with
+	 * itself. But we still need to check for references whose
+	 * names are in the "refs/foo/bar/" namespace, because they
+	 * *do* conflict.
+	 */
+	strbuf_addstr(&dirname, refname + dirname.len);
+	strbuf_addch(&dirname, '/');
+
+	iter = refs_ref_iterator_begin(refs, dirname.buf, 0,
+				       DO_FOR_EACH_INCLUDE_BROKEN);
+	while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
+		if (skip &&
+		    string_list_has_string(skip, iter->refname))
+			continue;
+
+		strbuf_addf(err, "'%s' exists; cannot create '%s'",
+			    iter->refname, refname);
+		ref_iterator_abort(iter);
+		goto cleanup;
+	}
+
+	if (ok != ITER_DONE)
+		die("BUG: error while iterating over references");
+
+	extra_refname = find_descendant_ref(dirname.buf, extras, skip);
+	if (extra_refname)
+		strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
+			    refname, extra_refname);
+	else
+		ret = 0;
+
+cleanup:
+	strbuf_release(&referent);
+	strbuf_release(&dirname);
+	return ret;
 }
 
-int for_each_reflog(each_ref_fn fn, void *cb_data)
+int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
 	struct ref_iterator *iter;
 
 	iter = refs->be->reflog_iterator_begin(refs);
@@ -1539,43 +1769,84 @@
 	return do_for_each_ref_iterator(iter, fn, cb_data);
 }
 
+int for_each_reflog(each_ref_fn fn, void *cb_data)
+{
+	return refs_for_each_reflog(get_main_ref_store(), fn, cb_data);
+}
+
+int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
+				     const char *refname,
+				     each_reflog_ent_fn fn,
+				     void *cb_data)
+{
+	return refs->be->for_each_reflog_ent_reverse(refs, refname,
+						     fn, cb_data);
+}
+
 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn,
 				void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	return refs_for_each_reflog_ent_reverse(get_main_ref_store(),
+						refname, fn, cb_data);
+}
 
-	return refs->be->for_each_reflog_ent_reverse(refs, refname,
-						     fn, cb_data);
+int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
+			     each_reflog_ent_fn fn, void *cb_data)
+{
+	return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
 }
 
 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn,
 			void *cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	return refs_for_each_reflog_ent(get_main_ref_store(), refname,
+					fn, cb_data);
+}
 
-	return refs->be->for_each_reflog_ent(refs, refname, fn, cb_data);
+int refs_reflog_exists(struct ref_store *refs, const char *refname)
+{
+	return refs->be->reflog_exists(refs, refname);
 }
 
 int reflog_exists(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	return refs_reflog_exists(get_main_ref_store(), refname);
+}
 
-	return refs->be->reflog_exists(refs, refname);
+int refs_create_reflog(struct ref_store *refs, const char *refname,
+		       int force_create, struct strbuf *err)
+{
+	return refs->be->create_reflog(refs, refname, force_create, err);
 }
 
 int safe_create_reflog(const char *refname, int force_create,
 		       struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	return refs_create_reflog(get_main_ref_store(), refname,
+				  force_create, err);
+}
 
-	return refs->be->create_reflog(refs, refname, force_create, err);
+int refs_delete_reflog(struct ref_store *refs, const char *refname)
+{
+	return refs->be->delete_reflog(refs, refname);
 }
 
 int delete_reflog(const char *refname)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	return refs_delete_reflog(get_main_ref_store(), refname);
+}
 
-	return refs->be->delete_reflog(refs, refname);
+int refs_reflog_expire(struct ref_store *refs,
+		       const char *refname, const unsigned char *sha1,
+		       unsigned int flags,
+		       reflog_expiry_prepare_fn prepare_fn,
+		       reflog_expiry_should_prune_fn should_prune_fn,
+		       reflog_expiry_cleanup_fn cleanup_fn,
+		       void *policy_cb_data)
+{
+	return refs->be->reflog_expire(refs, refname, sha1, flags,
+				       prepare_fn, should_prune_fn,
+				       cleanup_fn, policy_cb_data);
 }
 
 int reflog_expire(const char *refname, const unsigned char *sha1,
@@ -1585,31 +1856,38 @@
 		  reflog_expiry_cleanup_fn cleanup_fn,
 		  void *policy_cb_data)
 {
-	struct ref_store *refs = get_ref_store(NULL);
-
-	return refs->be->reflog_expire(refs, refname, sha1, flags,
-				       prepare_fn, should_prune_fn,
-				       cleanup_fn, policy_cb_data);
+	return refs_reflog_expire(get_main_ref_store(),
+				  refname, sha1, flags,
+				  prepare_fn, should_prune_fn,
+				  cleanup_fn, policy_cb_data);
 }
 
 int initial_ref_transaction_commit(struct ref_transaction *transaction,
 				   struct strbuf *err)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	struct ref_store *refs = transaction->ref_store;
 
 	return refs->be->initial_transaction_commit(refs, transaction, err);
 }
 
+int refs_delete_refs(struct ref_store *refs, struct string_list *refnames,
+		     unsigned int flags)
+{
+	return refs->be->delete_refs(refs, refnames, flags);
+}
+
 int delete_refs(struct string_list *refnames, unsigned int flags)
 {
-	struct ref_store *refs = get_ref_store(NULL);
+	return refs_delete_refs(get_main_ref_store(), refnames, flags);
+}
 
-	return refs->be->delete_refs(refs, refnames, flags);
+int refs_rename_ref(struct ref_store *refs, const char *oldref,
+		    const char *newref, const char *logmsg)
+{
+	return refs->be->rename_ref(refs, oldref, newref, logmsg);
 }
 
 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 {
-	struct ref_store *refs = get_ref_store(NULL);
-
-	return refs->be->rename_ref(refs, oldref, newref, logmsg);
+	return refs_rename_ref(get_main_ref_store(), oldref, newref, logmsg);
 }
diff --git a/refs.h b/refs.h
index 3df0d45..07cf4cd 100644
--- a/refs.h
+++ b/refs.h
@@ -1,6 +1,11 @@
 #ifndef REFS_H
 #define REFS_H
 
+struct object_id;
+struct ref_store;
+struct strbuf;
+struct string_list;
+
 /*
  * Resolve a reference, recursively following symbolic refererences.
  *
@@ -52,16 +57,50 @@
 #define RESOLVE_REF_NO_RECURSE 0x02
 #define RESOLVE_REF_ALLOW_BAD_NAME 0x04
 
+const char *refs_resolve_ref_unsafe(struct ref_store *refs,
+				    const char *refname,
+				    int resolve_flags,
+				    unsigned char *sha1,
+				    int *flags);
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       unsigned char *sha1, int *flags);
 
+char *refs_resolve_refdup(struct ref_store *refs,
+			  const char *refname, int resolve_flags,
+			  unsigned char *sha1, int *flags);
 char *resolve_refdup(const char *refname, int resolve_flags,
 		     unsigned char *sha1, int *flags);
 
+int refs_read_ref_full(struct ref_store *refs, const char *refname,
+		       int resolve_flags, unsigned char *sha1, int *flags);
 int read_ref_full(const char *refname, int resolve_flags,
 		  unsigned char *sha1, int *flags);
 int read_ref(const char *refname, unsigned char *sha1);
 
+/*
+ * Return 0 if a reference named refname could be created without
+ * conflicting with the name of an existing reference. Otherwise,
+ * return a negative value and write an explanation to err. If extras
+ * is non-NULL, it is a list of additional refnames with which refname
+ * is not allowed to conflict. If skip is non-NULL, ignore potential
+ * conflicts with refs in skip (e.g., because they are scheduled for
+ * deletion in the same operation). Behavior is undefined if the same
+ * name is listed in both extras and skip.
+ *
+ * Two reference names conflict if one of them exactly matches the
+ * leading components of the other; e.g., "foo/bar" conflicts with
+ * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
+ * "foo/barbados".
+ *
+ * extras and skip must be sorted.
+ */
+
+int refs_verify_refname_available(struct ref_store *refs,
+				  const char *refname,
+				  const struct string_list *extras,
+				  const struct string_list *skip,
+				  struct strbuf *err);
+
 int ref_exists(const char *refname);
 
 int should_autocreate_reflog(const char *refname);
@@ -78,6 +117,8 @@
  * Symbolic references are considered unpeelable, even if they
  * ultimately resolve to a peelable tag.
  */
+int refs_peel_ref(struct ref_store *refs, const char *refname,
+		  unsigned char *sha1);
 int peel_ref(const char *refname, unsigned char *sha1);
 
 /**
@@ -189,8 +230,19 @@
  * it is not safe to modify references while an iteration is in
  * progress, unless the same callback function invocation that
  * modifies the reference also returns a nonzero value to immediately
- * stop the iteration.
+ * stop the iteration. Returned references are sorted.
  */
+int refs_for_each_ref(struct ref_store *refs,
+		      each_ref_fn fn, void *cb_data);
+int refs_for_each_ref_in(struct ref_store *refs, const char *prefix,
+			 each_ref_fn fn, void *cb_data);
+int refs_for_each_tag_ref(struct ref_store *refs,
+			  each_ref_fn fn, void *cb_data);
+int refs_for_each_branch_ref(struct ref_store *refs,
+			     each_ref_fn fn, void *cb_data);
+int refs_for_each_remote_ref(struct ref_store *refs,
+			     each_ref_fn fn, void *cb_data);
+
 int head_ref(each_ref_fn fn, void *cb_data);
 int for_each_ref(each_ref_fn fn, void *cb_data);
 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);
@@ -220,6 +272,7 @@
 int for_each_namespaced_ref(each_ref_fn fn, void *cb_data);
 
 /* can be used to learn about broken ref and symref */
+int refs_for_each_rawref(struct ref_store *refs, each_ref_fn fn, void *cb_data);
 int for_each_rawref(each_ref_fn fn, void *cb_data);
 
 static inline const char *has_glob_specials(const char *pattern)
@@ -243,7 +296,7 @@
  * Write a packed-refs file for the current repository.
  * flags: Combination of the above PACK_REFS_* flags.
  */
-int pack_refs(unsigned int flags);
+int refs_pack_refs(struct ref_store *refs, unsigned int flags);
 
 /*
  * Flags controlling ref_transaction_update(), ref_transaction_create(), etc.
@@ -258,6 +311,8 @@
 /*
  * Setup reflog before using. Fill in err and return -1 on failure.
  */
+int refs_create_reflog(struct ref_store *refs, const char *refname,
+		       int force_create, struct strbuf *err);
 int safe_create_reflog(const char *refname, int force_create, struct strbuf *err);
 
 /** Reads log for the value of ref during at_time. **/
@@ -267,6 +322,7 @@
 		unsigned long *cutoff_time, int *cutoff_tz, int *cutoff_cnt);
 
 /** Check if a particular reflog exists */
+int refs_reflog_exists(struct ref_store *refs, const char *refname);
 int reflog_exists(const char *refname);
 
 /*
@@ -276,6 +332,10 @@
  * exists, regardless of its old value. It is an error for old_sha1 to
  * be NULL_SHA1. flags is passed through to ref_transaction_delete().
  */
+int refs_delete_ref(struct ref_store *refs, const char *msg,
+		    const char *refname,
+		    const unsigned char *old_sha1,
+		    unsigned int flags);
 int delete_ref(const char *msg, const char *refname,
 	       const unsigned char *old_sha1, unsigned int flags);
 
@@ -285,9 +345,12 @@
  * an all-or-nothing transaction). flags is passed through to
  * ref_transaction_delete().
  */
+int refs_delete_refs(struct ref_store *refs, struct string_list *refnames,
+		     unsigned int flags);
 int delete_refs(struct string_list *refnames, unsigned int flags);
 
 /** Delete a reflog */
+int refs_delete_reflog(struct ref_store *refs, const char *refname);
 int delete_reflog(const char *refname);
 
 /* iterate over reflog entries */
@@ -296,13 +359,20 @@
 		const char *committer, unsigned long timestamp,
 		int tz, const char *msg, void *cb_data);
 
+int refs_for_each_reflog_ent(struct ref_store *refs, const char *refname,
+			     each_reflog_ent_fn fn, void *cb_data);
+int refs_for_each_reflog_ent_reverse(struct ref_store *refs,
+				     const char *refname,
+				     each_reflog_ent_fn fn,
+				     void *cb_data);
 int for_each_reflog_ent(const char *refname, each_reflog_ent_fn fn, void *cb_data);
 int for_each_reflog_ent_reverse(const char *refname, each_reflog_ent_fn fn, void *cb_data);
 
 /*
  * Calls the specified function for each reflog file until it returns nonzero,
- * and returns the value
+ * and returns the value. Reflog file order is unspecified.
  */
+int refs_for_each_reflog(struct ref_store *refs, each_ref_fn fn, void *cb_data);
 int for_each_reflog(each_ref_fn fn, void *cb_data);
 
 #define REFNAME_ALLOW_ONELEVEL 1
@@ -323,8 +393,12 @@
 char *shorten_unambiguous_ref(const char *refname, int strict);
 
 /** rename ref, return 0 on success **/
+int refs_rename_ref(struct ref_store *refs, const char *oldref,
+		    const char *newref, const char *logmsg);
 int rename_ref(const char *oldref, const char *newref, const char *logmsg);
 
+int refs_create_symref(struct ref_store *refs, const char *refname,
+		       const char *target, const char *logmsg);
 int create_symref(const char *refname, const char *target, const char *logmsg);
 
 /*
@@ -347,6 +421,8 @@
  * Begin a reference transaction.  The reference transaction must
  * be freed by calling ref_transaction_free().
  */
+struct ref_transaction *ref_store_transaction_begin(struct ref_store *refs,
+						    struct strbuf *err);
 struct ref_transaction *ref_transaction_begin(struct strbuf *err);
 
 /*
@@ -481,6 +557,9 @@
  * ref_transaction_update(). Handle errors as requested by the `onerr`
  * argument.
  */
+int refs_update_ref(struct ref_store *refs, const char *msg, const char *refname,
+		    const unsigned char *new_sha1, const unsigned char *old_sha1,
+		    unsigned int flags, enum action_on_err onerr);
 int update_ref(const char *msg, const char *refname,
 	       const unsigned char *new_sha1, const unsigned char *old_sha1,
 	       unsigned int flags, enum action_on_err onerr);
@@ -547,6 +626,14 @@
  * enum expire_reflog_flags. The three function pointers are described
  * above. On success, return zero.
  */
+int refs_reflog_expire(struct ref_store *refs,
+		       const char *refname,
+		       const unsigned char *sha1,
+		       unsigned int flags,
+		       reflog_expiry_prepare_fn prepare_fn,
+		       reflog_expiry_should_prune_fn should_prune_fn,
+		       reflog_expiry_cleanup_fn cleanup_fn,
+		       void *policy_cb_data);
 int reflog_expire(const char *refname, const unsigned char *sha1,
 		  unsigned int flags,
 		  reflog_expiry_prepare_fn prepare_fn,
@@ -556,4 +643,17 @@
 
 int ref_storage_backend_exists(const char *name);
 
+struct ref_store *get_main_ref_store(void);
+/*
+ * Return the ref_store instance for the specified submodule. For the
+ * main repository, use submodule==NULL; such a call cannot fail. For
+ * a submodule, the submodule must exist and be a nonbare repository,
+ * otherwise return NULL. If the requested reference store has not yet
+ * been initialized, initialize it first.
+ *
+ * For backwards compatibility, submodule=="" is treated the same as
+ * submodule==NULL.
+ */
+struct ref_store *get_submodule_ref_store(const char *submodule);
+
 #endif /* REFS_H */
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 50188e9..83ea080 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -1,6 +1,7 @@
 #include "../cache.h"
 #include "../refs.h"
 #include "refs-internal.h"
+#include "ref-cache.h"
 #include "../iterator.h"
 #include "../dir-iterator.h"
 #include "../lockfile.h"
@@ -13,507 +14,6 @@
 	struct object_id old_oid;
 };
 
-struct ref_entry;
-
-/*
- * Information used (along with the information in ref_entry) to
- * describe a single cached reference.  This data structure only
- * occurs embedded in a union in struct ref_entry, and only when
- * (ref_entry->flag & REF_DIR) is zero.
- */
-struct ref_value {
-	/*
-	 * The name of the object to which this reference resolves
-	 * (which may be a tag object).  If REF_ISBROKEN, this is
-	 * null.  If REF_ISSYMREF, then this is the name of the object
-	 * referred to by the last reference in the symlink chain.
-	 */
-	struct object_id oid;
-
-	/*
-	 * If REF_KNOWS_PEELED, then this field holds the peeled value
-	 * of this reference, or null if the reference is known not to
-	 * be peelable.  See the documentation for peel_ref() for an
-	 * exact definition of "peelable".
-	 */
-	struct object_id peeled;
-};
-
-struct files_ref_store;
-
-/*
- * Information used (along with the information in ref_entry) to
- * describe a level in the hierarchy of references.  This data
- * structure only occurs embedded in a union in struct ref_entry, and
- * only when (ref_entry.flag & REF_DIR) is set.  In that case,
- * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
- * in the directory have already been read:
- *
- *     (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
- *         or packed references, already read.
- *
- *     (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
- *         references that hasn't been read yet (nor has any of its
- *         subdirectories).
- *
- * Entries within a directory are stored within a growable array of
- * pointers to ref_entries (entries, nr, alloc).  Entries 0 <= i <
- * sorted are sorted by their component name in strcmp() order and the
- * remaining entries are unsorted.
- *
- * Loose references are read lazily, one directory at a time.  When a
- * directory of loose references is read, then all of the references
- * in that directory are stored, and REF_INCOMPLETE stubs are created
- * for any subdirectories, but the subdirectories themselves are not
- * read.  The reading is triggered by get_ref_dir().
- */
-struct ref_dir {
-	int nr, alloc;
-
-	/*
-	 * Entries with index 0 <= i < sorted are sorted by name.  New
-	 * entries are appended to the list unsorted, and are sorted
-	 * only when required; thus we avoid the need to sort the list
-	 * after the addition of every reference.
-	 */
-	int sorted;
-
-	/* A pointer to the files_ref_store that contains this ref_dir. */
-	struct files_ref_store *ref_store;
-
-	struct ref_entry **entries;
-};
-
-/*
- * Bit values for ref_entry::flag.  REF_ISSYMREF=0x01,
- * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
- * public values; see refs.h.
- */
-
-/*
- * The field ref_entry->u.value.peeled of this value entry contains
- * the correct peeled value for the reference, which might be
- * null_sha1 if the reference is not a tag or if it is broken.
- */
-#define REF_KNOWS_PEELED 0x10
-
-/* ref_entry represents a directory of references */
-#define REF_DIR 0x20
-
-/*
- * Entry has not yet been read from disk (used only for REF_DIR
- * entries representing loose references)
- */
-#define REF_INCOMPLETE 0x40
-
-/*
- * A ref_entry represents either a reference or a "subdirectory" of
- * references.
- *
- * Each directory in the reference namespace is represented by a
- * ref_entry with (flags & REF_DIR) set and containing a subdir member
- * that holds the entries in that directory that have been read so
- * far.  If (flags & REF_INCOMPLETE) is set, then the directory and
- * its subdirectories haven't been read yet.  REF_INCOMPLETE is only
- * used for loose reference directories.
- *
- * References are represented by a ref_entry with (flags & REF_DIR)
- * unset and a value member that describes the reference's value.  The
- * flag member is at the ref_entry level, but it is also needed to
- * interpret the contents of the value field (in other words, a
- * ref_value object is not very much use without the enclosing
- * ref_entry).
- *
- * Reference names cannot end with slash and directories' names are
- * always stored with a trailing slash (except for the top-level
- * directory, which is always denoted by "").  This has two nice
- * consequences: (1) when the entries in each subdir are sorted
- * lexicographically by name (as they usually are), the references in
- * a whole tree can be generated in lexicographic order by traversing
- * the tree in left-to-right, depth-first order; (2) the names of
- * references and subdirectories cannot conflict, and therefore the
- * presence of an empty subdirectory does not block the creation of a
- * similarly-named reference.  (The fact that reference names with the
- * same leading components can conflict *with each other* is a
- * separate issue that is regulated by verify_refname_available().)
- *
- * Please note that the name field contains the fully-qualified
- * reference (or subdirectory) name.  Space could be saved by only
- * storing the relative names.  But that would require the full names
- * to be generated on the fly when iterating in do_for_each_ref(), and
- * would break callback functions, who have always been able to assume
- * that the name strings that they are passed will not be freed during
- * the iteration.
- */
-struct ref_entry {
-	unsigned char flag; /* ISSYMREF? ISPACKED? */
-	union {
-		struct ref_value value; /* if not (flags&REF_DIR) */
-		struct ref_dir subdir; /* if (flags&REF_DIR) */
-	} u;
-	/*
-	 * The full name of the reference (e.g., "refs/heads/master")
-	 * or the full name of the directory with a trailing slash
-	 * (e.g., "refs/heads/"):
-	 */
-	char name[FLEX_ARRAY];
-};
-
-static void read_loose_refs(const char *dirname, struct ref_dir *dir);
-static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len);
-static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
-					  const char *dirname, size_t len,
-					  int incomplete);
-static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
-
-static struct ref_dir *get_ref_dir(struct ref_entry *entry)
-{
-	struct ref_dir *dir;
-	assert(entry->flag & REF_DIR);
-	dir = &entry->u.subdir;
-	if (entry->flag & REF_INCOMPLETE) {
-		read_loose_refs(entry->name, dir);
-
-		/*
-		 * Manually add refs/bisect, which, being
-		 * per-worktree, might not appear in the directory
-		 * listing for refs/ in the main repo.
-		 */
-		if (!strcmp(entry->name, "refs/")) {
-			int pos = search_ref_dir(dir, "refs/bisect/", 12);
-			if (pos < 0) {
-				struct ref_entry *child_entry;
-				child_entry = create_dir_entry(dir->ref_store,
-							       "refs/bisect/",
-							       12, 1);
-				add_entry_to_dir(dir, child_entry);
-				read_loose_refs("refs/bisect",
-						&child_entry->u.subdir);
-			}
-		}
-		entry->flag &= ~REF_INCOMPLETE;
-	}
-	return dir;
-}
-
-static struct ref_entry *create_ref_entry(const char *refname,
-					  const unsigned char *sha1, int flag,
-					  int check_name)
-{
-	struct ref_entry *ref;
-
-	if (check_name &&
-	    check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
-		die("Reference has invalid format: '%s'", refname);
-	FLEX_ALLOC_STR(ref, name, refname);
-	hashcpy(ref->u.value.oid.hash, sha1);
-	oidclr(&ref->u.value.peeled);
-	ref->flag = flag;
-	return ref;
-}
-
-static void clear_ref_dir(struct ref_dir *dir);
-
-static void free_ref_entry(struct ref_entry *entry)
-{
-	if (entry->flag & REF_DIR) {
-		/*
-		 * Do not use get_ref_dir() here, as that might
-		 * trigger the reading of loose refs.
-		 */
-		clear_ref_dir(&entry->u.subdir);
-	}
-	free(entry);
-}
-
-/*
- * Add a ref_entry to the end of dir (unsorted).  Entry is always
- * stored directly in dir; no recursion into subdirectories is
- * done.
- */
-static void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
-{
-	ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
-	dir->entries[dir->nr++] = entry;
-	/* optimize for the case that entries are added in order */
-	if (dir->nr == 1 ||
-	    (dir->nr == dir->sorted + 1 &&
-	     strcmp(dir->entries[dir->nr - 2]->name,
-		    dir->entries[dir->nr - 1]->name) < 0))
-		dir->sorted = dir->nr;
-}
-
-/*
- * Clear and free all entries in dir, recursively.
- */
-static void clear_ref_dir(struct ref_dir *dir)
-{
-	int i;
-	for (i = 0; i < dir->nr; i++)
-		free_ref_entry(dir->entries[i]);
-	free(dir->entries);
-	dir->sorted = dir->nr = dir->alloc = 0;
-	dir->entries = NULL;
-}
-
-/*
- * Create a struct ref_entry object for the specified dirname.
- * dirname is the name of the directory with a trailing slash (e.g.,
- * "refs/heads/") or "" for the top-level directory.
- */
-static struct ref_entry *create_dir_entry(struct files_ref_store *ref_store,
-					  const char *dirname, size_t len,
-					  int incomplete)
-{
-	struct ref_entry *direntry;
-	FLEX_ALLOC_MEM(direntry, name, dirname, len);
-	direntry->u.subdir.ref_store = ref_store;
-	direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
-	return direntry;
-}
-
-static int ref_entry_cmp(const void *a, const void *b)
-{
-	struct ref_entry *one = *(struct ref_entry **)a;
-	struct ref_entry *two = *(struct ref_entry **)b;
-	return strcmp(one->name, two->name);
-}
-
-static void sort_ref_dir(struct ref_dir *dir);
-
-struct string_slice {
-	size_t len;
-	const char *str;
-};
-
-static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
-{
-	const struct string_slice *key = key_;
-	const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
-	int cmp = strncmp(key->str, ent->name, key->len);
-	if (cmp)
-		return cmp;
-	return '\0' - (unsigned char)ent->name[key->len];
-}
-
-/*
- * Return the index of the entry with the given refname from the
- * ref_dir (non-recursively), sorting dir if necessary.  Return -1 if
- * no such entry is found.  dir must already be complete.
- */
-static int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
-{
-	struct ref_entry **r;
-	struct string_slice key;
-
-	if (refname == NULL || !dir->nr)
-		return -1;
-
-	sort_ref_dir(dir);
-	key.len = len;
-	key.str = refname;
-	r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
-		    ref_entry_cmp_sslice);
-
-	if (r == NULL)
-		return -1;
-
-	return r - dir->entries;
-}
-
-/*
- * Search for a directory entry directly within dir (without
- * recursing).  Sort dir if necessary.  subdirname must be a directory
- * name (i.e., end in '/').  If mkdir is set, then create the
- * directory if it is missing; otherwise, return NULL if the desired
- * directory cannot be found.  dir must already be complete.
- */
-static struct ref_dir *search_for_subdir(struct ref_dir *dir,
-					 const char *subdirname, size_t len,
-					 int mkdir)
-{
-	int entry_index = search_ref_dir(dir, subdirname, len);
-	struct ref_entry *entry;
-	if (entry_index == -1) {
-		if (!mkdir)
-			return NULL;
-		/*
-		 * Since dir is complete, the absence of a subdir
-		 * means that the subdir really doesn't exist;
-		 * therefore, create an empty record for it but mark
-		 * the record complete.
-		 */
-		entry = create_dir_entry(dir->ref_store, subdirname, len, 0);
-		add_entry_to_dir(dir, entry);
-	} else {
-		entry = dir->entries[entry_index];
-	}
-	return get_ref_dir(entry);
-}
-
-/*
- * If refname is a reference name, find the ref_dir within the dir
- * tree that should hold refname.  If refname is a directory name
- * (i.e., ends in '/'), then return that ref_dir itself.  dir must
- * represent the top-level directory and must already be complete.
- * Sort ref_dirs and recurse into subdirectories as necessary.  If
- * mkdir is set, then create any missing directories; otherwise,
- * return NULL if the desired directory cannot be found.
- */
-static struct ref_dir *find_containing_dir(struct ref_dir *dir,
-					   const char *refname, int mkdir)
-{
-	const char *slash;
-	for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
-		size_t dirnamelen = slash - refname + 1;
-		struct ref_dir *subdir;
-		subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
-		if (!subdir) {
-			dir = NULL;
-			break;
-		}
-		dir = subdir;
-	}
-
-	return dir;
-}
-
-/*
- * Find the value entry with the given name in dir, sorting ref_dirs
- * and recursing into subdirectories as necessary.  If the name is not
- * found or it corresponds to a directory entry, return NULL.
- */
-static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
-{
-	int entry_index;
-	struct ref_entry *entry;
-	dir = find_containing_dir(dir, refname, 0);
-	if (!dir)
-		return NULL;
-	entry_index = search_ref_dir(dir, refname, strlen(refname));
-	if (entry_index == -1)
-		return NULL;
-	entry = dir->entries[entry_index];
-	return (entry->flag & REF_DIR) ? NULL : entry;
-}
-
-/*
- * Remove the entry with the given name from dir, recursing into
- * subdirectories as necessary.  If refname is the name of a directory
- * (i.e., ends with '/'), then remove the directory and its contents.
- * If the removal was successful, return the number of entries
- * remaining in the directory entry that contained the deleted entry.
- * If the name was not found, return -1.  Please note that this
- * function only deletes the entry from the cache; it does not delete
- * it from the filesystem or ensure that other cache entries (which
- * might be symbolic references to the removed entry) are updated.
- * Nor does it remove any containing dir entries that might be made
- * empty by the removal.  dir must represent the top-level directory
- * and must already be complete.
- */
-static int remove_entry(struct ref_dir *dir, const char *refname)
-{
-	int refname_len = strlen(refname);
-	int entry_index;
-	struct ref_entry *entry;
-	int is_dir = refname[refname_len - 1] == '/';
-	if (is_dir) {
-		/*
-		 * refname represents a reference directory.  Remove
-		 * the trailing slash; otherwise we will get the
-		 * directory *representing* refname rather than the
-		 * one *containing* it.
-		 */
-		char *dirname = xmemdupz(refname, refname_len - 1);
-		dir = find_containing_dir(dir, dirname, 0);
-		free(dirname);
-	} else {
-		dir = find_containing_dir(dir, refname, 0);
-	}
-	if (!dir)
-		return -1;
-	entry_index = search_ref_dir(dir, refname, refname_len);
-	if (entry_index == -1)
-		return -1;
-	entry = dir->entries[entry_index];
-
-	memmove(&dir->entries[entry_index],
-		&dir->entries[entry_index + 1],
-		(dir->nr - entry_index - 1) * sizeof(*dir->entries)
-		);
-	dir->nr--;
-	if (dir->sorted > entry_index)
-		dir->sorted--;
-	free_ref_entry(entry);
-	return dir->nr;
-}
-
-/*
- * Add a ref_entry to the ref_dir (unsorted), recursing into
- * subdirectories as necessary.  dir must represent the top-level
- * directory.  Return 0 on success.
- */
-static int add_ref(struct ref_dir *dir, struct ref_entry *ref)
-{
-	dir = find_containing_dir(dir, ref->name, 1);
-	if (!dir)
-		return -1;
-	add_entry_to_dir(dir, ref);
-	return 0;
-}
-
-/*
- * Emit a warning and return true iff ref1 and ref2 have the same name
- * and the same sha1.  Die if they have the same name but different
- * sha1s.
- */
-static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
-{
-	if (strcmp(ref1->name, ref2->name))
-		return 0;
-
-	/* Duplicate name; make sure that they don't conflict: */
-
-	if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
-		/* This is impossible by construction */
-		die("Reference directory conflict: %s", ref1->name);
-
-	if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
-		die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
-
-	warning("Duplicated ref: %s", ref1->name);
-	return 1;
-}
-
-/*
- * Sort the entries in dir non-recursively (if they are not already
- * sorted) and remove any duplicate entries.
- */
-static void sort_ref_dir(struct ref_dir *dir)
-{
-	int i, j;
-	struct ref_entry *last = NULL;
-
-	/*
-	 * This check also prevents passing a zero-length array to qsort(),
-	 * which is a problem on some platforms.
-	 */
-	if (dir->sorted == dir->nr)
-		return;
-
-	QSORT(dir->entries, dir->nr, ref_entry_cmp);
-
-	/* Remove any duplicates: */
-	for (i = 0, j = 0; j < dir->nr; j++) {
-		struct ref_entry *entry = dir->entries[j];
-		if (last && is_dup_ref(last, entry))
-			free_ref_entry(entry);
-		else
-			last = dir->entries[i++] = entry;
-	}
-	dir->sorted = dir->nr = i;
-}
-
 /*
  * Return true if refname, which has the specified oid and flags, can
  * be resolved to an object in the database. If the referred-to object
@@ -532,358 +32,8 @@
 	return 1;
 }
 
-/*
- * Return true if the reference described by entry can be resolved to
- * an object in the database; otherwise, emit a warning and return
- * false.
- */
-static int entry_resolves_to_object(struct ref_entry *entry)
-{
-	return ref_resolves_to_object(entry->name,
-				      &entry->u.value.oid, entry->flag);
-}
-
-typedef int each_ref_entry_fn(struct ref_entry *entry, void *cb_data);
-
-/*
- * Call fn for each reference in dir that has index in the range
- * offset <= index < dir->nr.  Recurse into subdirectories that are in
- * that index range, sorting them before iterating.  This function
- * does not sort dir itself; it should be sorted beforehand.  fn is
- * called for all references, including broken ones.
- */
-static int do_for_each_entry_in_dir(struct ref_dir *dir, int offset,
-				    each_ref_entry_fn fn, void *cb_data)
-{
-	int i;
-	assert(dir->sorted == dir->nr);
-	for (i = offset; i < dir->nr; i++) {
-		struct ref_entry *entry = dir->entries[i];
-		int retval;
-		if (entry->flag & REF_DIR) {
-			struct ref_dir *subdir = get_ref_dir(entry);
-			sort_ref_dir(subdir);
-			retval = do_for_each_entry_in_dir(subdir, 0, fn, cb_data);
-		} else {
-			retval = fn(entry, cb_data);
-		}
-		if (retval)
-			return retval;
-	}
-	return 0;
-}
-
-/*
- * Load all of the refs from the dir into our in-memory cache. The hard work
- * of loading loose refs is done by get_ref_dir(), so we just need to recurse
- * through all of the sub-directories. We do not even need to care about
- * sorting, as traversal order does not matter to us.
- */
-static void prime_ref_dir(struct ref_dir *dir)
-{
-	int i;
-	for (i = 0; i < dir->nr; i++) {
-		struct ref_entry *entry = dir->entries[i];
-		if (entry->flag & REF_DIR)
-			prime_ref_dir(get_ref_dir(entry));
-	}
-}
-
-/*
- * A level in the reference hierarchy that is currently being iterated
- * through.
- */
-struct cache_ref_iterator_level {
-	/*
-	 * The ref_dir being iterated over at this level. The ref_dir
-	 * is sorted before being stored here.
-	 */
-	struct ref_dir *dir;
-
-	/*
-	 * The index of the current entry within dir (which might
-	 * itself be a directory). If index == -1, then the iteration
-	 * hasn't yet begun. If index == dir->nr, then the iteration
-	 * through this level is over.
-	 */
-	int index;
-};
-
-/*
- * Represent an iteration through a ref_dir in the memory cache. The
- * iteration recurses through subdirectories.
- */
-struct cache_ref_iterator {
-	struct ref_iterator base;
-
-	/*
-	 * The number of levels currently on the stack. This is always
-	 * at least 1, because when it becomes zero the iteration is
-	 * ended and this struct is freed.
-	 */
-	size_t levels_nr;
-
-	/* The number of levels that have been allocated on the stack */
-	size_t levels_alloc;
-
-	/*
-	 * A stack of levels. levels[0] is the uppermost level that is
-	 * being iterated over in this iteration. (This is not
-	 * necessary the top level in the references hierarchy. If we
-	 * are iterating through a subtree, then levels[0] will hold
-	 * the ref_dir for that subtree, and subsequent levels will go
-	 * on from there.)
-	 */
-	struct cache_ref_iterator_level *levels;
-};
-
-static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
-{
-	struct cache_ref_iterator *iter =
-		(struct cache_ref_iterator *)ref_iterator;
-
-	while (1) {
-		struct cache_ref_iterator_level *level =
-			&iter->levels[iter->levels_nr - 1];
-		struct ref_dir *dir = level->dir;
-		struct ref_entry *entry;
-
-		if (level->index == -1)
-			sort_ref_dir(dir);
-
-		if (++level->index == level->dir->nr) {
-			/* This level is exhausted; pop up a level */
-			if (--iter->levels_nr == 0)
-				return ref_iterator_abort(ref_iterator);
-
-			continue;
-		}
-
-		entry = dir->entries[level->index];
-
-		if (entry->flag & REF_DIR) {
-			/* push down a level */
-			ALLOC_GROW(iter->levels, iter->levels_nr + 1,
-				   iter->levels_alloc);
-
-			level = &iter->levels[iter->levels_nr++];
-			level->dir = get_ref_dir(entry);
-			level->index = -1;
-		} else {
-			iter->base.refname = entry->name;
-			iter->base.oid = &entry->u.value.oid;
-			iter->base.flags = entry->flag;
-			return ITER_OK;
-		}
-	}
-}
-
-static enum peel_status peel_entry(struct ref_entry *entry, int repeel);
-
-static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
-				   struct object_id *peeled)
-{
-	struct cache_ref_iterator *iter =
-		(struct cache_ref_iterator *)ref_iterator;
-	struct cache_ref_iterator_level *level;
-	struct ref_entry *entry;
-
-	level = &iter->levels[iter->levels_nr - 1];
-
-	if (level->index == -1)
-		die("BUG: peel called before advance for cache iterator");
-
-	entry = level->dir->entries[level->index];
-
-	if (peel_entry(entry, 0))
-		return -1;
-	oidcpy(peeled, &entry->u.value.peeled);
-	return 0;
-}
-
-static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator)
-{
-	struct cache_ref_iterator *iter =
-		(struct cache_ref_iterator *)ref_iterator;
-
-	free(iter->levels);
-	base_ref_iterator_free(ref_iterator);
-	return ITER_DONE;
-}
-
-static struct ref_iterator_vtable cache_ref_iterator_vtable = {
-	cache_ref_iterator_advance,
-	cache_ref_iterator_peel,
-	cache_ref_iterator_abort
-};
-
-static struct ref_iterator *cache_ref_iterator_begin(struct ref_dir *dir)
-{
-	struct cache_ref_iterator *iter;
-	struct ref_iterator *ref_iterator;
-	struct cache_ref_iterator_level *level;
-
-	iter = xcalloc(1, sizeof(*iter));
-	ref_iterator = &iter->base;
-	base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable);
-	ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
-
-	iter->levels_nr = 1;
-	level = &iter->levels[0];
-	level->index = -1;
-	level->dir = dir;
-
-	return ref_iterator;
-}
-
-struct nonmatching_ref_data {
-	const struct string_list *skip;
-	const char *conflicting_refname;
-};
-
-static int nonmatching_ref_fn(struct ref_entry *entry, void *vdata)
-{
-	struct nonmatching_ref_data *data = vdata;
-
-	if (data->skip && string_list_has_string(data->skip, entry->name))
-		return 0;
-
-	data->conflicting_refname = entry->name;
-	return 1;
-}
-
-/*
- * Return 0 if a reference named refname could be created without
- * conflicting with the name of an existing reference in dir.
- * See verify_refname_available for more information.
- */
-static int verify_refname_available_dir(const char *refname,
-					const struct string_list *extras,
-					const struct string_list *skip,
-					struct ref_dir *dir,
-					struct strbuf *err)
-{
-	const char *slash;
-	const char *extra_refname;
-	int pos;
-	struct strbuf dirname = STRBUF_INIT;
-	int ret = -1;
-
-	/*
-	 * For the sake of comments in this function, suppose that
-	 * refname is "refs/foo/bar".
-	 */
-
-	assert(err);
-
-	strbuf_grow(&dirname, strlen(refname) + 1);
-	for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
-		/* Expand dirname to the new prefix, not including the trailing slash: */
-		strbuf_add(&dirname, refname + dirname.len, slash - refname - dirname.len);
-
-		/*
-		 * We are still at a leading dir of the refname (e.g.,
-		 * "refs/foo"; if there is a reference with that name,
-		 * it is a conflict, *unless* it is in skip.
-		 */
-		if (dir) {
-			pos = search_ref_dir(dir, dirname.buf, dirname.len);
-			if (pos >= 0 &&
-			    (!skip || !string_list_has_string(skip, dirname.buf))) {
-				/*
-				 * We found a reference whose name is
-				 * a proper prefix of refname; e.g.,
-				 * "refs/foo", and is not in skip.
-				 */
-				strbuf_addf(err, "'%s' exists; cannot create '%s'",
-					    dirname.buf, refname);
-				goto cleanup;
-			}
-		}
-
-		if (extras && string_list_has_string(extras, dirname.buf) &&
-		    (!skip || !string_list_has_string(skip, dirname.buf))) {
-			strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
-				    refname, dirname.buf);
-			goto cleanup;
-		}
-
-		/*
-		 * Otherwise, we can try to continue our search with
-		 * the next component. So try to look up the
-		 * directory, e.g., "refs/foo/". If we come up empty,
-		 * we know there is nothing under this whole prefix,
-		 * but even in that case we still have to continue the
-		 * search for conflicts with extras.
-		 */
-		strbuf_addch(&dirname, '/');
-		if (dir) {
-			pos = search_ref_dir(dir, dirname.buf, dirname.len);
-			if (pos < 0) {
-				/*
-				 * There was no directory "refs/foo/",
-				 * so there is nothing under this
-				 * whole prefix. So there is no need
-				 * to continue looking for conflicting
-				 * references. But we need to continue
-				 * looking for conflicting extras.
-				 */
-				dir = NULL;
-			} else {
-				dir = get_ref_dir(dir->entries[pos]);
-			}
-		}
-	}
-
-	/*
-	 * We are at the leaf of our refname (e.g., "refs/foo/bar").
-	 * There is no point in searching for a reference with that
-	 * name, because a refname isn't considered to conflict with
-	 * itself. But we still need to check for references whose
-	 * names are in the "refs/foo/bar/" namespace, because they
-	 * *do* conflict.
-	 */
-	strbuf_addstr(&dirname, refname + dirname.len);
-	strbuf_addch(&dirname, '/');
-
-	if (dir) {
-		pos = search_ref_dir(dir, dirname.buf, dirname.len);
-
-		if (pos >= 0) {
-			/*
-			 * We found a directory named "$refname/"
-			 * (e.g., "refs/foo/bar/"). It is a problem
-			 * iff it contains any ref that is not in
-			 * "skip".
-			 */
-			struct nonmatching_ref_data data;
-
-			data.skip = skip;
-			data.conflicting_refname = NULL;
-			dir = get_ref_dir(dir->entries[pos]);
-			sort_ref_dir(dir);
-			if (do_for_each_entry_in_dir(dir, 0, nonmatching_ref_fn, &data)) {
-				strbuf_addf(err, "'%s' exists; cannot create '%s'",
-					    data.conflicting_refname, refname);
-				goto cleanup;
-			}
-		}
-	}
-
-	extra_refname = find_descendant_ref(dirname.buf, extras, skip);
-	if (extra_refname)
-		strbuf_addf(err, "cannot process '%s' and '%s' at the same time",
-			    refname, extra_refname);
-	else
-		ret = 0;
-
-cleanup:
-	strbuf_release(&dirname);
-	return ret;
-}
-
 struct packed_ref_cache {
-	struct ref_entry *root;
+	struct ref_cache *cache;
 
 	/*
 	 * Count of references to the data structure in this instance,
@@ -912,15 +62,13 @@
  */
 struct files_ref_store {
 	struct ref_store base;
+	unsigned int store_flags;
 
-	/*
-	 * The name of the submodule represented by this object, or
-	 * NULL if it represents the main repository's reference
-	 * store:
-	 */
-	const char *submodule;
+	char *gitdir;
+	char *gitcommondir;
+	char *packed_refs_path;
 
-	struct ref_entry *loose;
+	struct ref_cache *loose;
 	struct packed_ref_cache *packed;
 };
 
@@ -942,7 +90,7 @@
 static int release_packed_ref_cache(struct packed_ref_cache *packed_refs)
 {
 	if (!--packed_refs->referrers) {
-		free_ref_entry(packed_refs->root);
+		free_ref_cache(packed_refs->cache);
 		stat_validity_clear(&packed_refs->validity);
 		free(packed_refs);
 		return 1;
@@ -966,7 +114,7 @@
 static void clear_loose_ref_cache(struct files_ref_store *refs)
 {
 	if (refs->loose) {
-		free_ref_entry(refs->loose);
+		free_ref_cache(refs->loose);
 		refs->loose = NULL;
 	}
 }
@@ -975,38 +123,47 @@
  * Create a new submodule ref cache and add it to the internal
  * set of caches.
  */
-static struct ref_store *files_ref_store_create(const char *submodule)
+static struct ref_store *files_ref_store_create(const char *gitdir,
+						unsigned int flags)
 {
 	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
+	struct strbuf sb = STRBUF_INIT;
 
 	base_ref_store_init(ref_store, &refs_be_files);
+	refs->store_flags = flags;
 
-	refs->submodule = xstrdup_or_null(submodule);
+	refs->gitdir = xstrdup(gitdir);
+	get_common_dir_noenv(&sb, gitdir);
+	refs->gitcommondir = strbuf_detach(&sb, NULL);
+	strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
+	refs->packed_refs_path = strbuf_detach(&sb, NULL);
 
 	return ref_store;
 }
 
 /*
- * Die if refs is for a submodule (i.e., not for the main repository).
- * caller is used in any necessary error messages.
+ * Die if refs is not the main ref store. caller is used in any
+ * necessary error messages.
  */
 static void files_assert_main_repository(struct files_ref_store *refs,
 					 const char *caller)
 {
-	if (refs->submodule)
-		die("BUG: %s called for a submodule", caller);
+	if (refs->store_flags & REF_STORE_MAIN)
+		return;
+
+	die("BUG: operation %s only allowed for main ref store", caller);
 }
 
 /*
  * Downcast ref_store to files_ref_store. Die if ref_store is not a
- * files_ref_store. If submodule_allowed is not true, then also die if
- * files_ref_store is for a submodule (i.e., not for the main
- * repository). caller is used in any necessary error messages.
+ * files_ref_store. required_flags is compared with ref_store's
+ * store_flags to ensure the ref_store has all required capabilities.
+ * "caller" is used in any necessary error messages.
  */
-static struct files_ref_store *files_downcast(
-		struct ref_store *ref_store, int submodule_allowed,
-		const char *caller)
+static struct files_ref_store *files_downcast(struct ref_store *ref_store,
+					      unsigned int required_flags,
+					      const char *caller)
 {
 	struct files_ref_store *refs;
 
@@ -1016,8 +173,9 @@
 
 	refs = (struct files_ref_store *)ref_store;
 
-	if (!submodule_allowed)
-		files_assert_main_repository(refs, caller);
+	if ((refs->store_flags & required_flags) != required_flags)
+		die("BUG: operation %s requires abilities 0x%x, but only have 0x%x",
+		    caller, required_flags, refs->store_flags);
 
 	return refs;
 }
@@ -1129,7 +287,7 @@
 			if (peeled == PEELED_FULLY ||
 			    (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
 				last->flag |= REF_KNOWS_PEELED;
-			add_ref(dir, last);
+			add_ref_entry(dir, last);
 			continue;
 		}
 		if (last &&
@@ -1150,19 +308,63 @@
 	strbuf_release(&line);
 }
 
+static const char *files_packed_refs_path(struct files_ref_store *refs)
+{
+	return refs->packed_refs_path;
+}
+
+static void files_reflog_path(struct files_ref_store *refs,
+			      struct strbuf *sb,
+			      const char *refname)
+{
+	if (!refname) {
+		/*
+		 * FIXME: of course this is wrong in multi worktree
+		 * setting. To be fixed real soon.
+		 */
+		strbuf_addf(sb, "%s/logs", refs->gitcommondir);
+		return;
+	}
+
+	switch (ref_type(refname)) {
+	case REF_TYPE_PER_WORKTREE:
+	case REF_TYPE_PSEUDOREF:
+		strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
+		break;
+	case REF_TYPE_NORMAL:
+		strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
+		break;
+	default:
+		die("BUG: unknown ref type %d of ref %s",
+		    ref_type(refname), refname);
+	}
+}
+
+static void files_ref_path(struct files_ref_store *refs,
+			   struct strbuf *sb,
+			   const char *refname)
+{
+	switch (ref_type(refname)) {
+	case REF_TYPE_PER_WORKTREE:
+	case REF_TYPE_PSEUDOREF:
+		strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
+		break;
+	case REF_TYPE_NORMAL:
+		strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
+		break;
+	default:
+		die("BUG: unknown ref type %d of ref %s",
+		    ref_type(refname), refname);
+	}
+}
+
 /*
  * Get the packed_ref_cache for the specified files_ref_store,
  * creating it if necessary.
  */
 static struct packed_ref_cache *get_packed_ref_cache(struct files_ref_store *refs)
 {
-	char *packed_refs_file;
-
-	if (refs->submodule)
-		packed_refs_file = git_pathdup_submodule(refs->submodule,
-							 "packed-refs");
-	else
-		packed_refs_file = git_pathdup("packed-refs");
+	const char *packed_refs_file = files_packed_refs_path(refs);
 
 	if (refs->packed &&
 	    !stat_validity_check(&refs->packed->validity, packed_refs_file))
@@ -1173,21 +375,21 @@
 
 		refs->packed = xcalloc(1, sizeof(*refs->packed));
 		acquire_packed_ref_cache(refs->packed);
-		refs->packed->root = create_dir_entry(refs, "", 0, 0);
+		refs->packed->cache = create_ref_cache(&refs->base, NULL);
+		refs->packed->cache->root->flag &= ~REF_INCOMPLETE;
 		f = fopen(packed_refs_file, "r");
 		if (f) {
 			stat_validity_update(&refs->packed->validity, fileno(f));
-			read_packed_refs(f, get_ref_dir(refs->packed->root));
+			read_packed_refs(f, get_ref_dir(refs->packed->cache->root));
 			fclose(f);
 		}
 	}
-	free(packed_refs_file);
 	return refs->packed;
 }
 
 static struct ref_dir *get_packed_ref_dir(struct packed_ref_cache *packed_ref_cache)
 {
-	return get_ref_dir(packed_ref_cache->root);
+	return get_ref_dir(packed_ref_cache->cache->root);
 }
 
 static struct ref_dir *get_packed_refs(struct files_ref_store *refs)
@@ -1208,8 +410,8 @@
 
 	if (!packed_ref_cache->lock)
 		die("internal error: packed refs not locked");
-	add_ref(get_packed_ref_dir(packed_ref_cache),
-		create_ref_entry(refname, sha1, REF_ISPACKED, 1));
+	add_ref_entry(get_packed_ref_dir(packed_ref_cache),
+		      create_ref_entry(refname, sha1, REF_ISPACKED, 1));
 }
 
 /*
@@ -1217,28 +419,21 @@
  * (without recursing).  dirname must end with '/'.  dir must be the
  * directory entry corresponding to dirname.
  */
-static void read_loose_refs(const char *dirname, struct ref_dir *dir)
+static void loose_fill_ref_dir(struct ref_store *ref_store,
+			       struct ref_dir *dir, const char *dirname)
 {
-	struct files_ref_store *refs = dir->ref_store;
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_READ, "fill_ref_dir");
 	DIR *d;
 	struct dirent *de;
 	int dirnamelen = strlen(dirname);
 	struct strbuf refname;
 	struct strbuf path = STRBUF_INIT;
 	size_t path_baselen;
-	int err = 0;
 
-	if (refs->submodule)
-		err = strbuf_git_path_submodule(&path, refs->submodule, "%s", dirname);
-	else
-		strbuf_git_path(&path, "%s", dirname);
+	files_ref_path(refs, &path, dirname);
 	path_baselen = path.len;
 
-	if (err) {
-		strbuf_release(&path);
-		return;
-	}
-
 	d = opendir(path.buf);
 	if (!d) {
 		strbuf_release(&path);
@@ -1264,10 +459,10 @@
 		} else if (S_ISDIR(st.st_mode)) {
 			strbuf_addch(&refname, '/');
 			add_entry_to_dir(dir,
-					 create_dir_entry(refs, refname.buf,
+					 create_dir_entry(dir->cache, refname.buf,
 							  refname.len, 1));
 		} else {
-			if (!resolve_ref_recursively(&refs->base,
+			if (!refs_resolve_ref_unsafe(&refs->base,
 						     refname.buf,
 						     RESOLVE_REF_READING,
 						     sha1, &flag)) {
@@ -1301,9 +496,24 @@
 	strbuf_release(&refname);
 	strbuf_release(&path);
 	closedir(d);
+
+	/*
+	 * Manually add refs/bisect, which, being per-worktree, might
+	 * not appear in the directory listing for refs/ in the main
+	 * repo.
+	 */
+	if (!strcmp(dirname, "refs/")) {
+		int pos = search_ref_dir(dir, "refs/bisect/", 12);
+
+		if (pos < 0) {
+			struct ref_entry *child_entry = create_dir_entry(
+					dir->cache, "refs/bisect/", 12, 1);
+			add_entry_to_dir(dir, child_entry);
+		}
+	}
 }
 
-static struct ref_dir *get_loose_refs(struct files_ref_store *refs)
+static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
 {
 	if (!refs->loose) {
 		/*
@@ -1311,14 +521,19 @@
 		 * are about to read the only subdirectory that can
 		 * hold references:
 		 */
-		refs->loose = create_dir_entry(refs, "", 0, 0);
+		refs->loose = create_ref_cache(&refs->base, loose_fill_ref_dir);
+
+		/* We're going to fill the top level ourselves: */
+		refs->loose->root->flag &= ~REF_INCOMPLETE;
+
 		/*
-		 * Create an incomplete entry for "refs/":
+		 * Add an incomplete entry for "refs/" (to be filled
+		 * lazily):
 		 */
-		add_entry_to_dir(get_ref_dir(refs->loose),
-				 create_dir_entry(refs, "refs/", 5, 1));
+		add_entry_to_dir(get_ref_dir(refs->loose->root),
+				 create_dir_entry(refs->loose, "refs/", 5, 1));
 	}
-	return get_ref_dir(refs->loose);
+	return refs->loose;
 }
 
 /*
@@ -1328,7 +543,7 @@
 static struct ref_entry *get_packed_ref(struct files_ref_store *refs,
 					const char *refname)
 {
-	return find_ref(get_packed_refs(refs), refname);
+	return find_ref_entry(get_packed_refs(refs), refname);
 }
 
 /*
@@ -1359,7 +574,7 @@
 			      struct strbuf *referent, unsigned int *type)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "read_raw_ref");
+		files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
 	struct strbuf sb_contents = STRBUF_INIT;
 	struct strbuf sb_path = STRBUF_INIT;
 	const char *path;
@@ -1373,10 +588,7 @@
 	*type = 0;
 	strbuf_reset(&sb_path);
 
-	if (refs->submodule)
-		strbuf_git_path_submodule(&sb_path, refs->submodule, "%s", refname);
-	else
-		strbuf_git_path(&sb_path, "%s", refname);
+	files_ref_path(refs, &sb_path, refname);
 
 	path = sb_path.buf;
 
@@ -1521,7 +733,7 @@
  *
  * If the reference doesn't already exist, verify that refname doesn't
  * have a D/F conflict with any existing references. extras and skip
- * are passed to verify_refname_available_dir() for this check.
+ * are passed to refs_verify_refname_available() for this check.
  *
  * If mustexist is not set and the reference is not found or is
  * broken, lock the reference anyway but clear sha1.
@@ -1536,7 +748,7 @@
  *
  * but it includes a lot more code to
  * - Deal with possible races with other processes
- * - Avoid calling verify_refname_available_dir() when it can be
+ * - Avoid calling refs_verify_refname_available() when it can be
  *   avoided, namely if we were successfully able to read the ref
  * - Generate informative error messages in the case of failure
  */
@@ -1564,7 +776,7 @@
 	*lock_p = lock = xcalloc(1, sizeof(*lock));
 
 	lock->ref_name = xstrdup(refname);
-	strbuf_git_path(&ref_file, "%s", refname);
+	files_ref_path(refs, &ref_file, refname);
 
 retry:
 	switch (safe_create_leading_directories(ref_file.buf)) {
@@ -1579,7 +791,8 @@
 		 * another reference such as "refs/foo". There is no
 		 * reason to expect this error to be transitory.
 		 */
-		if (verify_refname_available(refname, extras, skip, err)) {
+		if (refs_verify_refname_available(&refs->base, refname,
+						  extras, skip, err)) {
 			if (mustexist) {
 				/*
 				 * To the user the relevant error is
@@ -1592,7 +805,8 @@
 			} else {
 				/*
 				 * The error message set by
-				 * verify_refname_available_dir() is OK.
+				 * refs_verify_refname_available() is
+				 * OK.
 				 */
 				ret = TRANSACTION_NAME_CONFLICT;
 			}
@@ -1682,10 +896,9 @@
 				goto error_return;
 			} else if (remove_dir_recursively(&ref_file,
 							  REMOVE_DIR_EMPTY_ONLY)) {
-				if (verify_refname_available_dir(
-						    refname, extras, skip,
-						    get_loose_refs(refs),
-						    err)) {
+				if (refs_verify_refname_available(
+						    &refs->base, refname,
+						    extras, skip, err)) {
 					/*
 					 * The error message set by
 					 * verify_refname_available() is OK.
@@ -1717,16 +930,13 @@
 
 		/*
 		 * If the ref did not exist and we are creating it,
-		 * make sure there is no existing packed ref whose
-		 * name begins with our refname, nor a packed ref
-		 * whose name is a proper prefix of our refname.
+		 * make sure there is no existing ref that conflicts
+		 * with refname:
 		 */
-		if (verify_refname_available_dir(
-				    refname, extras, skip,
-				    get_packed_refs(refs),
-				    err)) {
+		if (refs_verify_refname_available(
+				    &refs->base, refname,
+				    extras, skip, err))
 			goto error_return;
-		}
 	}
 
 	ret = 0;
@@ -1741,45 +951,12 @@
 	return ret;
 }
 
-/*
- * Peel the entry (if possible) and return its new peel_status.  If
- * repeel is true, re-peel the entry even if there is an old peeled
- * value that is already stored in it.
- *
- * It is OK to call this function with a packed reference entry that
- * might be stale and might even refer to an object that has since
- * been garbage-collected.  In such a case, if the entry has
- * REF_KNOWS_PEELED then leave the status unchanged and return
- * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
- */
-static enum peel_status peel_entry(struct ref_entry *entry, int repeel)
-{
-	enum peel_status status;
-
-	if (entry->flag & REF_KNOWS_PEELED) {
-		if (repeel) {
-			entry->flag &= ~REF_KNOWS_PEELED;
-			oidclr(&entry->u.value.peeled);
-		} else {
-			return is_null_oid(&entry->u.value.peeled) ?
-				PEEL_NON_TAG : PEEL_PEELED;
-		}
-	}
-	if (entry->flag & REF_ISBROKEN)
-		return PEEL_BROKEN;
-	if (entry->flag & REF_ISSYMREF)
-		return PEEL_IS_SYMREF;
-
-	status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
-	if (status == PEEL_PEELED || status == PEEL_NON_TAG)
-		entry->flag |= REF_KNOWS_PEELED;
-	return status;
-}
-
 static int files_peel_ref(struct ref_store *ref_store,
 			  const char *refname, unsigned char *sha1)
 {
-	struct files_ref_store *refs = files_downcast(ref_store, 0, "peel_ref");
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_READ | REF_STORE_ODB,
+			       "peel_ref");
 	int flag;
 	unsigned char base[20];
 
@@ -1792,7 +969,8 @@
 		return 0;
 	}
 
-	if (read_ref_full(refname, RESOLVE_REF_READING, base, &flag))
+	if (refs_read_ref_full(ref_store, refname,
+			       RESOLVE_REF_READING, base, &flag))
 		return -1;
 
 	/*
@@ -1887,21 +1065,20 @@
 		struct ref_store *ref_store,
 		const char *prefix, unsigned int flags)
 {
-	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "ref_iterator_begin");
-	struct ref_dir *loose_dir, *packed_dir;
+	struct files_ref_store *refs;
 	struct ref_iterator *loose_iter, *packed_iter;
 	struct files_ref_iterator *iter;
 	struct ref_iterator *ref_iterator;
 
-	if (!refs)
-		return empty_ref_iterator_begin();
-
 	if (ref_paranoia < 0)
 		ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
 	if (ref_paranoia)
 		flags |= DO_FOR_EACH_INCLUDE_BROKEN;
 
+	refs = files_downcast(ref_store,
+			      REF_STORE_READ | (ref_paranoia ? 0 : REF_STORE_ODB),
+			      "ref_iterator_begin");
+
 	iter = xcalloc(1, sizeof(*iter));
 	ref_iterator = &iter->base;
 	base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable);
@@ -1912,41 +1089,24 @@
 	 * condition if loose refs are migrated to the packed-refs
 	 * file by a simultaneous process, but our in-memory view is
 	 * from before the migration. We ensure this as follows:
-	 * First, we call prime_ref_dir(), which pre-reads the loose
-	 * references for the subtree into the cache. (If they've
-	 * already been read, that's OK; we only need to guarantee
-	 * that they're read before the packed refs, not *how much*
-	 * before.) After that, we call get_packed_ref_cache(), which
-	 * internally checks whether the packed-ref cache is up to
-	 * date with what is on disk, and re-reads it if not.
+	 * First, we call start the loose refs iteration with its
+	 * `prime_ref` argument set to true. This causes the loose
+	 * references in the subtree to be pre-read into the cache.
+	 * (If they've already been read, that's OK; we only need to
+	 * guarantee that they're read before the packed refs, not
+	 * *how much* before.) After that, we call
+	 * get_packed_ref_cache(), which internally checks whether the
+	 * packed-ref cache is up to date with what is on disk, and
+	 * re-reads it if not.
 	 */
 
-	loose_dir = get_loose_refs(refs);
-
-	if (prefix && *prefix)
-		loose_dir = find_containing_dir(loose_dir, prefix, 0);
-
-	if (loose_dir) {
-		prime_ref_dir(loose_dir);
-		loose_iter = cache_ref_iterator_begin(loose_dir);
-	} else {
-		/* There's nothing to iterate over. */
-		loose_iter = empty_ref_iterator_begin();
-	}
+	loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
+					      prefix, 1);
 
 	iter->packed_ref_cache = get_packed_ref_cache(refs);
 	acquire_packed_ref_cache(iter->packed_ref_cache);
-	packed_dir = get_packed_ref_dir(iter->packed_ref_cache);
-
-	if (prefix && *prefix)
-		packed_dir = find_containing_dir(packed_dir, prefix, 0);
-
-	if (packed_dir) {
-		packed_iter = cache_ref_iterator_begin(packed_dir);
-	} else {
-		/* There's nothing to iterate over. */
-		packed_iter = empty_ref_iterator_begin();
-	}
+	packed_iter = cache_ref_iterator_begin(iter->packed_ref_cache->cache,
+					       prefix, 0);
 
 	iter->iter0 = overlay_ref_iterator_begin(loose_iter, packed_iter);
 	iter->flags = flags;
@@ -1960,15 +1120,15 @@
  * on success. On error, write an error message to err, set errno, and
  * return a negative value.
  */
-static int verify_lock(struct ref_lock *lock,
+static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
 		       const unsigned char *old_sha1, int mustexist,
 		       struct strbuf *err)
 {
 	assert(err);
 
-	if (read_ref_full(lock->ref_name,
-			  mustexist ? RESOLVE_REF_READING : 0,
-			  lock->old_oid.hash, NULL)) {
+	if (refs_read_ref_full(ref_store, lock->ref_name,
+			       mustexist ? RESOLVE_REF_READING : 0,
+			       lock->old_oid.hash, NULL)) {
 		if (old_sha1) {
 			int save_errno = errno;
 			strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
@@ -2036,9 +1196,10 @@
 	if (flags & REF_DELETING)
 		resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
 
-	strbuf_git_path(&ref_file, "%s", refname);
-	resolved = !!resolve_ref_unsafe(refname, resolve_flags,
-					lock->old_oid.hash, type);
+	files_ref_path(refs, &ref_file, refname);
+	resolved = !!refs_resolve_ref_unsafe(&refs->base,
+					     refname, resolve_flags,
+					     lock->old_oid.hash, type);
 	if (!resolved && errno == EISDIR) {
 		/*
 		 * we are trying to lock foo but we used to
@@ -2048,22 +1209,22 @@
 		 */
 		if (remove_empty_directories(&ref_file)) {
 			last_errno = errno;
-			if (!verify_refname_available_dir(
-					    refname, extras, skip,
-					    get_loose_refs(refs), err))
+			if (!refs_verify_refname_available(
+					    &refs->base,
+					    refname, extras, skip, err))
 				strbuf_addf(err, "there are still refs under '%s'",
 					    refname);
 			goto error_return;
 		}
-		resolved = !!resolve_ref_unsafe(refname, resolve_flags,
-						lock->old_oid.hash, type);
+		resolved = !!refs_resolve_ref_unsafe(&refs->base,
+						     refname, resolve_flags,
+						     lock->old_oid.hash, type);
 	}
 	if (!resolved) {
 		last_errno = errno;
 		if (last_errno != ENOTDIR ||
-		    !verify_refname_available_dir(
-				    refname, extras, skip,
-				    get_loose_refs(refs), err))
+		    !refs_verify_refname_available(&refs->base, refname,
+						   extras, skip, err))
 			strbuf_addf(err, "unable to resolve reference '%s': %s",
 				    refname, strerror(last_errno));
 
@@ -2077,9 +1238,8 @@
 	 * our refname.
 	 */
 	if (is_null_oid(&lock->old_oid) &&
-	    verify_refname_available_dir(refname, extras, skip,
-					 get_packed_refs(refs),
-					 err)) {
+	    refs_verify_refname_available(&refs->base, refname,
+					  extras, skip, err)) {
 		last_errno = ENOTDIR;
 		goto error_return;
 	}
@@ -2094,7 +1254,7 @@
 		goto error_return;
 	}
 
-	if (verify_lock(lock, old_sha1, mustexist, err)) {
+	if (verify_lock(&refs->base, lock, old_sha1, mustexist, err)) {
 		last_errno = errno;
 		goto error_return;
 	}
@@ -2114,8 +1274,9 @@
  * Write an entry to the packed-refs file for the specified refname.
  * If peeled is non-NULL, write it as the entry's peeled value.
  */
-static void write_packed_entry(FILE *fh, char *refname, unsigned char *sha1,
-			       unsigned char *peeled)
+static void write_packed_entry(FILE *fh, const char *refname,
+			       const unsigned char *sha1,
+			       const unsigned char *peeled)
 {
 	fprintf_or_die(fh, "%s %s\n", sha1_to_hex(sha1), refname);
 	if (peeled)
@@ -2123,22 +1284,6 @@
 }
 
 /*
- * An each_ref_entry_fn that writes the entry to a packed-refs file.
- */
-static int write_packed_entry_fn(struct ref_entry *entry, void *cb_data)
-{
-	enum peel_status peel_status = peel_entry(entry, 0);
-
-	if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
-		error("internal error: %s is not a valid packed reference!",
-		      entry->name);
-	write_packed_entry(cb_data, entry->name, entry->u.value.oid.hash,
-			   peel_status == PEEL_PEELED ?
-			   entry->u.value.peeled.hash : NULL);
-	return 0;
-}
-
-/*
  * Lock the packed-refs file for writing. Flags is passed to
  * hold_lock_file_for_update(). Return 0 on success. On errors, set
  * errno appropriately and return a nonzero value.
@@ -2157,7 +1302,7 @@
 	}
 
 	if (hold_lock_file_for_update_timeout(
-			    &packlock, git_path("packed-refs"),
+			    &packlock, files_packed_refs_path(refs),
 			    flags, timeout_value) < 0)
 		return -1;
 	/*
@@ -2183,9 +1328,10 @@
 {
 	struct packed_ref_cache *packed_ref_cache =
 		get_packed_ref_cache(refs);
-	int error = 0;
+	int ok, error = 0;
 	int save_errno = 0;
 	FILE *out;
+	struct ref_iterator *iter;
 
 	files_assert_main_repository(refs, "commit_packed_refs");
 
@@ -2197,8 +1343,18 @@
 		die_errno("unable to fdopen packed-refs descriptor");
 
 	fprintf_or_die(out, "%s", PACKED_REFS_HEADER);
-	do_for_each_entry_in_dir(get_packed_ref_dir(packed_ref_cache),
-				 0, write_packed_entry_fn, out);
+
+	iter = cache_ref_iterator_begin(packed_ref_cache->cache, NULL, 0);
+	while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
+		struct object_id peeled;
+		int peel_error = ref_iterator_peel(iter, &peeled);
+
+		write_packed_entry(out, iter->refname, iter->oid->hash,
+				   peel_error ? NULL : peeled.hash);
+	}
+
+	if (ok != ITER_DONE)
+		die("error while iterating over references");
 
 	if (commit_lock_file(packed_ref_cache->lock)) {
 		save_errno = errno;
@@ -2236,65 +1392,6 @@
 	char name[FLEX_ARRAY];
 };
 
-struct pack_refs_cb_data {
-	unsigned int flags;
-	struct ref_dir *packed_refs;
-	struct ref_to_prune *ref_to_prune;
-};
-
-/*
- * An each_ref_entry_fn that is run over loose references only.  If
- * the loose reference can be packed, add an entry in the packed ref
- * cache.  If the reference should be pruned, also add it to
- * ref_to_prune in the pack_refs_cb_data.
- */
-static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
-{
-	struct pack_refs_cb_data *cb = cb_data;
-	enum peel_status peel_status;
-	struct ref_entry *packed_entry;
-	int is_tag_ref = starts_with(entry->name, "refs/tags/");
-
-	/* Do not pack per-worktree refs: */
-	if (ref_type(entry->name) != REF_TYPE_NORMAL)
-		return 0;
-
-	/* ALWAYS pack tags */
-	if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref)
-		return 0;
-
-	/* Do not pack symbolic or broken refs: */
-	if ((entry->flag & REF_ISSYMREF) || !entry_resolves_to_object(entry))
-		return 0;
-
-	/* Add a packed ref cache entry equivalent to the loose entry. */
-	peel_status = peel_entry(entry, 1);
-	if (peel_status != PEEL_PEELED && peel_status != PEEL_NON_TAG)
-		die("internal error peeling reference %s (%s)",
-		    entry->name, oid_to_hex(&entry->u.value.oid));
-	packed_entry = find_ref(cb->packed_refs, entry->name);
-	if (packed_entry) {
-		/* Overwrite existing packed entry with info from loose entry */
-		packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
-		oidcpy(&packed_entry->u.value.oid, &entry->u.value.oid);
-	} else {
-		packed_entry = create_ref_entry(entry->name, entry->u.value.oid.hash,
-						REF_ISPACKED | REF_KNOWS_PEELED, 0);
-		add_ref(cb->packed_refs, packed_entry);
-	}
-	oidcpy(&packed_entry->u.value.peeled, &entry->u.value.peeled);
-
-	/* Schedule the loose reference for pruning if requested. */
-	if ((cb->flags & PACK_REFS_PRUNE)) {
-		struct ref_to_prune *n;
-		FLEX_ALLOC_STR(n, name, entry->name);
-		hashcpy(n->sha1, entry->u.value.oid.hash);
-		n->next = cb->ref_to_prune;
-		cb->ref_to_prune = n;
-	}
-	return 0;
-}
-
 enum {
 	REMOVE_EMPTY_PARENTS_REF = 0x01,
 	REMOVE_EMPTY_PARENTS_REFLOG = 0x02
@@ -2306,9 +1403,12 @@
  * subdirs. flags is a combination of REMOVE_EMPTY_PARENTS_REF and/or
  * REMOVE_EMPTY_PARENTS_REFLOG.
  */
-static void try_remove_empty_parents(const char *refname, unsigned int flags)
+static void try_remove_empty_parents(struct files_ref_store *refs,
+				     const char *refname,
+				     unsigned int flags)
 {
 	struct strbuf buf = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
 	char *p, *q;
 	int i;
 
@@ -2330,18 +1430,23 @@
 		if (q == p)
 			break;
 		strbuf_setlen(&buf, q - buf.buf);
-		if ((flags & REMOVE_EMPTY_PARENTS_REF) &&
-		    rmdir(git_path("%s", buf.buf)))
+
+		strbuf_reset(&sb);
+		files_ref_path(refs, &sb, buf.buf);
+		if ((flags & REMOVE_EMPTY_PARENTS_REF) && rmdir(sb.buf))
 			flags &= ~REMOVE_EMPTY_PARENTS_REF;
-		if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) &&
-		    rmdir(git_path("logs/%s", buf.buf)))
+
+		strbuf_reset(&sb);
+		files_reflog_path(refs, &sb, buf.buf);
+		if ((flags & REMOVE_EMPTY_PARENTS_REFLOG) && rmdir(sb.buf))
 			flags &= ~REMOVE_EMPTY_PARENTS_REFLOG;
 	}
 	strbuf_release(&buf);
+	strbuf_release(&sb);
 }
 
 /* make sure nobody touched the ref, and unlink */
-static void prune_ref(struct ref_to_prune *r)
+static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
@@ -2349,7 +1454,7 @@
 	if (check_refname_format(r->name, 0))
 		return;
 
-	transaction = ref_transaction_begin(&err);
+	transaction = ref_store_transaction_begin(&refs->base, &err);
 	if (!transaction ||
 	    ref_transaction_delete(transaction, r->name, r->sha1,
 				   REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
@@ -2363,10 +1468,10 @@
 	strbuf_release(&err);
 }
 
-static void prune_refs(struct ref_to_prune *r)
+static void prune_refs(struct files_ref_store *refs, struct ref_to_prune *r)
 {
 	while (r) {
-		prune_ref(r);
+		prune_ref(refs, r);
 		r = r->next;
 	}
 }
@@ -2374,22 +1479,75 @@
 static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "pack_refs");
-	struct pack_refs_cb_data cbdata;
-
-	memset(&cbdata, 0, sizeof(cbdata));
-	cbdata.flags = flags;
+		files_downcast(ref_store, REF_STORE_WRITE | REF_STORE_ODB,
+			       "pack_refs");
+	struct ref_iterator *iter;
+	struct ref_dir *packed_refs;
+	int ok;
+	struct ref_to_prune *refs_to_prune = NULL;
 
 	lock_packed_refs(refs, LOCK_DIE_ON_ERROR);
-	cbdata.packed_refs = get_packed_refs(refs);
+	packed_refs = get_packed_refs(refs);
 
-	do_for_each_entry_in_dir(get_loose_refs(refs), 0,
-				 pack_if_possible_fn, &cbdata);
+	iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
+	while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
+		/*
+		 * If the loose reference can be packed, add an entry
+		 * in the packed ref cache. If the reference should be
+		 * pruned, also add it to refs_to_prune.
+		 */
+		struct ref_entry *packed_entry;
+		int is_tag_ref = starts_with(iter->refname, "refs/tags/");
+
+		/* Do not pack per-worktree refs: */
+		if (ref_type(iter->refname) != REF_TYPE_NORMAL)
+			continue;
+
+		/* ALWAYS pack tags */
+		if (!(flags & PACK_REFS_ALL) && !is_tag_ref)
+			continue;
+
+		/* Do not pack symbolic or broken refs: */
+		if (iter->flags & REF_ISSYMREF)
+			continue;
+
+		if (!ref_resolves_to_object(iter->refname, iter->oid, iter->flags))
+			continue;
+
+		/*
+		 * Create an entry in the packed-refs cache equivalent
+		 * to the one from the loose ref cache, except that
+		 * we don't copy the peeled status, because we want it
+		 * to be re-peeled.
+		 */
+		packed_entry = find_ref_entry(packed_refs, iter->refname);
+		if (packed_entry) {
+			/* Overwrite existing packed entry with info from loose entry */
+			packed_entry->flag = REF_ISPACKED;
+			oidcpy(&packed_entry->u.value.oid, iter->oid);
+		} else {
+			packed_entry = create_ref_entry(iter->refname, iter->oid->hash,
+							REF_ISPACKED, 0);
+			add_ref_entry(packed_refs, packed_entry);
+		}
+		oidclr(&packed_entry->u.value.peeled);
+
+		/* Schedule the loose reference for pruning if requested. */
+		if ((flags & PACK_REFS_PRUNE)) {
+			struct ref_to_prune *n;
+			FLEX_ALLOC_STR(n, name, iter->refname);
+			hashcpy(n->sha1, iter->oid->hash);
+			n->next = refs_to_prune;
+			refs_to_prune = n;
+		}
+	}
+	if (ok != ITER_DONE)
+		die("error while iterating over references");
 
 	if (commit_packed_refs(refs))
 		die_errno("unable to overwrite old ref-pack file");
 
-	prune_refs(cbdata.ref_to_prune);
+	prune_refs(refs, refs_to_prune);
 	return 0;
 }
 
@@ -2423,14 +1581,14 @@
 		return 0; /* no refname exists in packed refs */
 
 	if (lock_packed_refs(refs, 0)) {
-		unable_to_lock_message(git_path("packed-refs"), errno, err);
+		unable_to_lock_message(files_packed_refs_path(refs), errno, err);
 		return -1;
 	}
 	packed = get_packed_refs(refs);
 
 	/* Remove refnames from the cache */
 	for_each_string_list_item(refname, refnames)
-		if (remove_entry(packed, refname->string) != -1)
+		if (remove_entry_from_dir(packed, refname->string) != -1)
 			removed = 1;
 	if (!removed) {
 		/*
@@ -2453,7 +1611,7 @@
 			     struct string_list *refnames, unsigned int flags)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "delete_refs");
+		files_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
 	struct strbuf err = STRBUF_INIT;
 	int i, result = 0;
 
@@ -2481,7 +1639,7 @@
 	for (i = 0; i < refnames->nr; i++) {
 		const char *refname = refnames->items[i].string;
 
-		if (delete_ref(NULL, refname, NULL, flags))
+		if (refs_delete_ref(&refs->base, NULL, refname, NULL, flags))
 			result |= error(_("could not remove reference %s"), refname);
 	}
 
@@ -2497,13 +1655,18 @@
  * IOW, to avoid cross device rename errors, the temporary renamed log must
  * live into logs/refs.
  */
-#define TMP_RENAMED_LOG  "logs/refs/.tmp-renamed-log"
+#define TMP_RENAMED_LOG  "refs/.tmp-renamed-log"
 
-static int rename_tmp_log_callback(const char *path, void *cb)
+struct rename_cb {
+	const char *tmp_renamed_log;
+	int true_errno;
+};
+
+static int rename_tmp_log_callback(const char *path, void *cb_data)
 {
-	int *true_errno = cb;
+	struct rename_cb *cb = cb_data;
 
-	if (rename(git_path(TMP_RENAMED_LOG), path)) {
+	if (rename(cb->tmp_renamed_log, path)) {
 		/*
 		 * rename(a, b) when b is an existing directory ought
 		 * to result in ISDIR, but Solaris 5.8 gives ENOTDIR.
@@ -2511,7 +1674,7 @@
 		 * but report EISDIR to raceproof_create_file() so
 		 * that it knows to retry.
 		 */
-		*true_errno = errno;
+		cb->true_errno = errno;
 		if (errno == ENOTDIR)
 			errno = EISDIR;
 		return -1;
@@ -2520,45 +1683,31 @@
 	}
 }
 
-static int rename_tmp_log(const char *newrefname)
+static int rename_tmp_log(struct files_ref_store *refs, const char *newrefname)
 {
-	char *path = git_pathdup("logs/%s", newrefname);
-	int ret, true_errno;
+	struct strbuf path = STRBUF_INIT;
+	struct strbuf tmp = STRBUF_INIT;
+	struct rename_cb cb;
+	int ret;
 
-	ret = raceproof_create_file(path, rename_tmp_log_callback, &true_errno);
+	files_reflog_path(refs, &path, newrefname);
+	files_reflog_path(refs, &tmp, TMP_RENAMED_LOG);
+	cb.tmp_renamed_log = tmp.buf;
+	ret = raceproof_create_file(path.buf, rename_tmp_log_callback, &cb);
 	if (ret) {
 		if (errno == EISDIR)
-			error("directory not empty: %s", path);
+			error("directory not empty: %s", path.buf);
 		else
 			error("unable to move logfile %s to %s: %s",
-			      git_path(TMP_RENAMED_LOG), path,
-			      strerror(true_errno));
+			      tmp.buf, path.buf,
+			      strerror(cb.true_errno));
 	}
 
-	free(path);
+	strbuf_release(&path);
+	strbuf_release(&tmp);
 	return ret;
 }
 
-static int files_verify_refname_available(struct ref_store *ref_store,
-					  const char *newname,
-					  const struct string_list *extras,
-					  const struct string_list *skip,
-					  struct strbuf *err)
-{
-	struct files_ref_store *refs =
-		files_downcast(ref_store, 1, "verify_refname_available");
-	struct ref_dir *packed_refs = get_packed_refs(refs);
-	struct ref_dir *loose_refs = get_loose_refs(refs);
-
-	if (verify_refname_available_dir(newname, extras, skip,
-					 packed_refs, err) ||
-	    verify_refname_available_dir(newname, extras, skip,
-					 loose_refs, err))
-		return -1;
-
-	return 0;
-}
-
 static int write_ref_to_lockfile(struct ref_lock *lock,
 				 const unsigned char *sha1, struct strbuf *err);
 static int commit_ref_update(struct files_ref_store *refs,
@@ -2571,32 +1720,52 @@
 			    const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "rename_ref");
+		files_downcast(ref_store, REF_STORE_WRITE, "rename_ref");
 	unsigned char sha1[20], orig_sha1[20];
 	int flag = 0, logmoved = 0;
 	struct ref_lock *lock;
 	struct stat loginfo;
-	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
+	struct strbuf sb_oldref = STRBUF_INIT;
+	struct strbuf sb_newref = STRBUF_INIT;
+	struct strbuf tmp_renamed_log = STRBUF_INIT;
+	int log, ret;
 	struct strbuf err = STRBUF_INIT;
 
-	if (log && S_ISLNK(loginfo.st_mode))
-		return error("reflog for %s is a symlink", oldrefname);
+	files_reflog_path(refs, &sb_oldref, oldrefname);
+	files_reflog_path(refs, &sb_newref, newrefname);
+	files_reflog_path(refs, &tmp_renamed_log, TMP_RENAMED_LOG);
 
-	if (!resolve_ref_unsafe(oldrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-				orig_sha1, &flag))
-		return error("refname %s not found", oldrefname);
+	log = !lstat(sb_oldref.buf, &loginfo);
+	if (log && S_ISLNK(loginfo.st_mode)) {
+		ret = error("reflog for %s is a symlink", oldrefname);
+		goto out;
+	}
 
-	if (flag & REF_ISSYMREF)
-		return error("refname %s is a symbolic ref, renaming it is not supported",
-			oldrefname);
-	if (!rename_ref_available(oldrefname, newrefname))
-		return 1;
+	if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
+				     RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
+				orig_sha1, &flag)) {
+		ret = error("refname %s not found", oldrefname);
+		goto out;
+	}
 
-	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
-		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
-			oldrefname, strerror(errno));
+	if (flag & REF_ISSYMREF) {
+		ret = error("refname %s is a symbolic ref, renaming it is not supported",
+			    oldrefname);
+		goto out;
+	}
+	if (!refs_rename_ref_available(&refs->base, oldrefname, newrefname)) {
+		ret = 1;
+		goto out;
+	}
 
-	if (delete_ref(logmsg, oldrefname, orig_sha1, REF_NODEREF)) {
+	if (log && rename(sb_oldref.buf, tmp_renamed_log.buf)) {
+		ret = error("unable to move logfile logs/%s to logs/"TMP_RENAMED_LOG": %s",
+			    oldrefname, strerror(errno));
+		goto out;
+	}
+
+	if (refs_delete_ref(&refs->base, logmsg, oldrefname,
+			    orig_sha1, REF_NODEREF)) {
 		error("unable to delete old %s", oldrefname);
 		goto rollback;
 	}
@@ -2608,14 +1777,16 @@
 	 * the safety anyway; we want to delete the reference whatever
 	 * its current value.
 	 */
-	if (!read_ref_full(newrefname, RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-			   sha1, NULL) &&
-	    delete_ref(NULL, newrefname, NULL, REF_NODEREF)) {
+	if (!refs_read_ref_full(&refs->base, newrefname,
+				RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
+				sha1, NULL) &&
+	    refs_delete_ref(&refs->base, NULL, newrefname,
+			    NULL, REF_NODEREF)) {
 		if (errno == EISDIR) {
 			struct strbuf path = STRBUF_INIT;
 			int result;
 
-			strbuf_git_path(&path, "%s", newrefname);
+			files_ref_path(refs, &path, newrefname);
 			result = remove_empty_directories(&path);
 			strbuf_release(&path);
 
@@ -2629,7 +1800,7 @@
 		}
 	}
 
-	if (log && rename_tmp_log(newrefname))
+	if (log && rename_tmp_log(refs, newrefname))
 		goto rollback;
 
 	logmoved = log;
@@ -2650,7 +1821,8 @@
 		goto rollback;
 	}
 
-	return 0;
+	ret = 0;
+	goto out;
 
  rollback:
 	lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
@@ -2671,15 +1843,20 @@
 	log_all_ref_updates = flag;
 
  rollbacklog:
-	if (logmoved && rename(git_path("logs/%s", newrefname), git_path("logs/%s", oldrefname)))
+	if (logmoved && rename(sb_newref.buf, sb_oldref.buf))
 		error("unable to restore logfile %s from %s: %s",
 			oldrefname, newrefname, strerror(errno));
 	if (!logmoved && log &&
-	    rename(git_path(TMP_RENAMED_LOG), git_path("logs/%s", oldrefname)))
-		error("unable to restore logfile %s from "TMP_RENAMED_LOG": %s",
+	    rename(tmp_renamed_log.buf, sb_oldref.buf))
+		error("unable to restore logfile %s from logs/"TMP_RENAMED_LOG": %s",
 			oldrefname, strerror(errno));
+	ret = 1;
+ out:
+	strbuf_release(&sb_newref);
+	strbuf_release(&sb_oldref);
+	strbuf_release(&tmp_renamed_log);
 
-	return 1;
+	return ret;
 }
 
 static int close_ref(struct ref_lock *lock)
@@ -2738,10 +1915,15 @@
  * set *logfd to -1. On failure, fill in *err, set *logfd to -1, and
  * return -1.
  */
-static int log_ref_setup(const char *refname, int force_create,
+static int log_ref_setup(struct files_ref_store *refs,
+			 const char *refname, int force_create,
 			 int *logfd, struct strbuf *err)
 {
-	char *logfile = git_pathdup("logs/%s", refname);
+	struct strbuf logfile_sb = STRBUF_INIT;
+	char *logfile;
+
+	files_reflog_path(refs, &logfile_sb, refname);
+	logfile = strbuf_detach(&logfile_sb, NULL);
 
 	if (force_create || should_autocreate_reflog(refname)) {
 		if (raceproof_create_file(logfile, open_or_create_logfile, logfd)) {
@@ -2791,12 +1973,11 @@
 			       const char *refname, int force_create,
 			       struct strbuf *err)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_WRITE, "create_reflog");
 	int fd;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "create_reflog");
-
-	if (log_ref_setup(refname, force_create, &fd, err))
+	if (log_ref_setup(refs, refname, force_create, &fd, err))
 		return -1;
 
 	if (fd >= 0)
@@ -2831,16 +2012,18 @@
 	return 0;
 }
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
-			const unsigned char *new_sha1, const char *msg,
-			int flags, struct strbuf *err)
+static int files_log_ref_write(struct files_ref_store *refs,
+			       const char *refname, const unsigned char *old_sha1,
+			       const unsigned char *new_sha1, const char *msg,
+			       int flags, struct strbuf *err)
 {
 	int logfd, result;
 
 	if (log_all_ref_updates == LOG_REFS_UNSET)
 		log_all_ref_updates = is_bare_repository() ? LOG_REFS_NONE : LOG_REFS_NORMAL;
 
-	result = log_ref_setup(refname, flags & REF_FORCE_CREATE_REFLOG,
+	result = log_ref_setup(refs, refname,
+			       flags & REF_FORCE_CREATE_REFLOG,
 			       &logfd, err);
 
 	if (result)
@@ -2851,18 +2034,24 @@
 	result = log_ref_write_fd(logfd, old_sha1, new_sha1,
 				  git_committer_info(0), msg);
 	if (result) {
+		struct strbuf sb = STRBUF_INIT;
 		int save_errno = errno;
 
+		files_reflog_path(refs, &sb, refname);
 		strbuf_addf(err, "unable to append to '%s': %s",
-			    git_path("logs/%s", refname), strerror(save_errno));
+			    sb.buf, strerror(save_errno));
+		strbuf_release(&sb);
 		close(logfd);
 		return -1;
 	}
 	if (close(logfd)) {
+		struct strbuf sb = STRBUF_INIT;
 		int save_errno = errno;
 
+		files_reflog_path(refs, &sb, refname);
 		strbuf_addf(err, "unable to append to '%s': %s",
-			    git_path("logs/%s", refname), strerror(save_errno));
+			    sb.buf, strerror(save_errno));
+		strbuf_release(&sb);
 		return -1;
 	}
 	return 0;
@@ -2920,7 +2109,8 @@
 	files_assert_main_repository(refs, "commit_ref_update");
 
 	clear_loose_ref_cache(refs);
-	if (files_log_ref_write(lock->ref_name, lock->old_oid.hash, sha1,
+	if (files_log_ref_write(refs, lock->ref_name,
+				lock->old_oid.hash, sha1,
 				logmsg, 0, err)) {
 		char *old_msg = strbuf_detach(err, NULL);
 		strbuf_addf(err, "cannot update the ref '%s': %s",
@@ -2947,13 +2137,15 @@
 		int head_flag;
 		const char *head_ref;
 
-		head_ref = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
-					      head_sha1, &head_flag);
+		head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
+						   RESOLVE_REF_READING,
+						   head_sha1, &head_flag);
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name)) {
 			struct strbuf log_err = STRBUF_INIT;
-			if (files_log_ref_write("HEAD", lock->old_oid.hash, sha1,
-					  logmsg, 0, &log_err)) {
+			if (files_log_ref_write(refs, "HEAD",
+						lock->old_oid.hash, sha1,
+						logmsg, 0, &log_err)) {
 				error("%s", log_err.buf);
 				strbuf_release(&log_err);
 			}
@@ -2985,24 +2177,28 @@
 	return ret;
 }
 
-static void update_symref_reflog(struct ref_lock *lock, const char *refname,
+static void update_symref_reflog(struct files_ref_store *refs,
+				 struct ref_lock *lock, const char *refname,
 				 const char *target, const char *logmsg)
 {
 	struct strbuf err = STRBUF_INIT;
 	unsigned char new_sha1[20];
-	if (logmsg && !read_ref(target, new_sha1) &&
-	    files_log_ref_write(refname, lock->old_oid.hash, new_sha1,
-				logmsg, 0, &err)) {
+	if (logmsg &&
+	    !refs_read_ref_full(&refs->base, target,
+				RESOLVE_REF_READING, new_sha1, NULL) &&
+	    files_log_ref_write(refs, refname, lock->old_oid.hash,
+				new_sha1, logmsg, 0, &err)) {
 		error("%s", err.buf);
 		strbuf_release(&err);
 	}
 }
 
-static int create_symref_locked(struct ref_lock *lock, const char *refname,
+static int create_symref_locked(struct files_ref_store *refs,
+				struct ref_lock *lock, const char *refname,
 				const char *target, const char *logmsg)
 {
 	if (prefer_symlink_refs && !create_ref_symlink(lock, target)) {
-		update_symref_reflog(lock, refname, target, logmsg);
+		update_symref_reflog(refs, lock, refname, target, logmsg);
 		return 0;
 	}
 
@@ -3010,7 +2206,7 @@
 		return error("unable to fdopen %s: %s",
 			     lock->lk->tempfile.filename.buf, strerror(errno));
 
-	update_symref_reflog(lock, refname, target, logmsg);
+	update_symref_reflog(refs, lock, refname, target, logmsg);
 
 	/* no error check; commit_ref will check ferror */
 	fprintf(lock->lk->tempfile.fp, "ref: %s\n", target);
@@ -3025,7 +2221,7 @@
 			       const char *logmsg)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "create_symref");
+		files_downcast(ref_store, REF_STORE_WRITE, "create_symref");
 	struct strbuf err = STRBUF_INIT;
 	struct ref_lock *lock;
 	int ret;
@@ -3039,13 +2235,22 @@
 		return -1;
 	}
 
-	ret = create_symref_locked(lock, refname, target, logmsg);
+	ret = create_symref_locked(refs, lock, refname, target, logmsg);
 	unlock_ref(lock);
 	return ret;
 }
 
 int set_worktree_head_symref(const char *gitdir, const char *target, const char *logmsg)
 {
+	/*
+	 * FIXME: this obviously will not work well for future refs
+	 * backends. This function needs to die.
+	 */
+	struct files_ref_store *refs =
+		files_downcast(get_main_ref_store(),
+			       REF_STORE_WRITE,
+			       "set_head_symref");
+
 	static struct lock_file head_lock;
 	struct ref_lock *lock;
 	struct strbuf head_path = STRBUF_INIT;
@@ -3072,7 +2277,7 @@
 	lock->lk = &head_lock;
 	lock->ref_name = xstrdup(head_rel);
 
-	ret = create_symref_locked(lock, head_rel, target, logmsg);
+	ret = create_symref_locked(refs, lock, head_rel, target, logmsg);
 
 	unlock_ref(lock); /* will free lock */
 	strbuf_release(&head_path);
@@ -3082,22 +2287,30 @@
 static int files_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_READ, "reflog_exists");
+	struct strbuf sb = STRBUF_INIT;
 	struct stat st;
+	int ret;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_exists");
-
-	return !lstat(git_path("logs/%s", refname), &st) &&
-		S_ISREG(st.st_mode);
+	files_reflog_path(refs, &sb, refname);
+	ret = !lstat(sb.buf, &st) && S_ISREG(st.st_mode);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int files_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "delete_reflog");
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_WRITE, "delete_reflog");
+	struct strbuf sb = STRBUF_INIT;
+	int ret;
 
-	return remove_path(git_path("logs/%s", refname));
+	files_reflog_path(refs, &sb, refname);
+	ret = remove_path(sb.buf);
+	strbuf_release(&sb);
+	return ret;
 }
 
 static int show_one_reflog_ent(struct strbuf *sb, each_reflog_ent_fn fn, void *cb_data)
@@ -3145,22 +2358,24 @@
 					     each_reflog_ent_fn fn,
 					     void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_READ,
+			       "for_each_reflog_ent_reverse");
 	struct strbuf sb = STRBUF_INIT;
 	FILE *logfp;
 	long pos;
 	int ret = 0, at_tail = 1;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent_reverse");
-
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	files_reflog_path(refs, &sb, refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
 	/* Jump to the end */
 	if (fseek(logfp, 0, SEEK_END) < 0)
-		return error("cannot seek back reflog for %s: %s",
-			     refname, strerror(errno));
+		ret = error("cannot seek back reflog for %s: %s",
+			    refname, strerror(errno));
 	pos = ftell(logfp);
 	while (!ret && 0 < pos) {
 		int cnt;
@@ -3170,13 +2385,17 @@
 
 		/* Fill next block from the end */
 		cnt = (sizeof(buf) < pos) ? sizeof(buf) : pos;
-		if (fseek(logfp, pos - cnt, SEEK_SET))
-			return error("cannot seek back reflog for %s: %s",
-				     refname, strerror(errno));
+		if (fseek(logfp, pos - cnt, SEEK_SET)) {
+			ret = error("cannot seek back reflog for %s: %s",
+				    refname, strerror(errno));
+			break;
+		}
 		nread = fread(buf, cnt, 1, logfp);
-		if (nread != 1)
-			return error("cannot read %d bytes from reflog for %s: %s",
-				     cnt, refname, strerror(errno));
+		if (nread != 1) {
+			ret = error("cannot read %d bytes from reflog for %s: %s",
+				    cnt, refname, strerror(errno));
+			break;
+		}
 		pos -= cnt;
 
 		scanp = endp = buf + cnt;
@@ -3252,14 +2471,16 @@
 				     const char *refname,
 				     each_reflog_ent_fn fn, void *cb_data)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_READ,
+			       "for_each_reflog_ent");
 	FILE *logfp;
 	struct strbuf sb = STRBUF_INIT;
 	int ret = 0;
 
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "for_each_reflog_ent");
-
-	logfp = fopen(git_path("logs/%s", refname), "r");
+	files_reflog_path(refs, &sb, refname);
+	logfp = fopen(sb.buf, "r");
+	strbuf_release(&sb);
 	if (!logfp)
 		return -1;
 
@@ -3273,6 +2494,7 @@
 struct files_reflog_iterator {
 	struct ref_iterator base;
 
+	struct ref_store *ref_store;
 	struct dir_iterator *dir_iterator;
 	struct object_id oid;
 };
@@ -3294,8 +2516,9 @@
 		if (ends_with(diter->basename, ".lock"))
 			continue;
 
-		if (read_ref_full(diter->relative_path, 0,
-				  iter->oid.hash, &flags)) {
+		if (refs_read_ref_full(iter->ref_store,
+				       diter->relative_path, 0,
+				       iter->oid.hash, &flags)) {
 			error("bad ref for %s", diter->path.buf);
 			continue;
 		}
@@ -3339,14 +2562,18 @@
 
 static struct ref_iterator *files_reflog_iterator_begin(struct ref_store *ref_store)
 {
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_READ,
+			       "reflog_iterator_begin");
 	struct files_reflog_iterator *iter = xcalloc(1, sizeof(*iter));
 	struct ref_iterator *ref_iterator = &iter->base;
-
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "reflog_iterator_begin");
+	struct strbuf sb = STRBUF_INIT;
 
 	base_ref_iterator_init(ref_iterator, &files_reflog_iterator_vtable);
-	iter->dir_iterator = dir_iterator_begin(git_path("logs"));
+	files_reflog_path(refs, &sb, NULL);
+	iter->dir_iterator = dir_iterator_begin(sb.buf);
+	iter->ref_store = ref_store;
+	strbuf_release(&sb);
 	return ref_iterator;
 }
 
@@ -3585,8 +2812,9 @@
 			 * the transaction, so we have to read it here
 			 * to record and possibly check old_sha1:
 			 */
-			if (read_ref_full(referent.buf, 0,
-					  lock->old_oid.hash, NULL)) {
+			if (refs_read_ref_full(&refs->base,
+					       referent.buf, 0,
+					       lock->old_oid.hash, NULL)) {
 				if (update->flags & REF_HAVE_OLD) {
 					strbuf_addf(err, "cannot lock ref '%s': "
 						    "error reading reference",
@@ -3676,7 +2904,8 @@
 				    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "ref_transaction_commit");
+		files_downcast(ref_store, REF_STORE_WRITE,
+			       "ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list refs_to_delete = STRING_LIST_INIT_NODUP;
 	struct string_list_item *ref_to_delete;
@@ -3684,6 +2913,7 @@
 	char *head_ref = NULL;
 	int head_type;
 	struct object_id head_oid;
+	struct strbuf sb = STRBUF_INIT;
 
 	assert(err);
 
@@ -3738,8 +2968,9 @@
 	 * head_ref within the transaction, then split_head_update()
 	 * arranges for the reflog of HEAD to be updated, too.
 	 */
-	head_ref = resolve_refdup("HEAD", RESOLVE_REF_NO_RECURSE,
-				  head_oid.hash, &head_type);
+	head_ref = refs_resolve_refdup(ref_store, "HEAD",
+				       RESOLVE_REF_NO_RECURSE,
+				       head_oid.hash, &head_type);
 
 	if (head_ref && !(head_type & REF_ISSYMREF)) {
 		free(head_ref);
@@ -3768,7 +2999,8 @@
 
 		if (update->flags & REF_NEEDS_COMMIT ||
 		    update->flags & REF_LOG_ONLY) {
-			if (files_log_ref_write(lock->ref_name,
+			if (files_log_ref_write(refs,
+						lock->ref_name,
 						lock->old_oid.hash,
 						update->new_sha1,
 						update->msg, update->flags,
@@ -3805,7 +3037,9 @@
 			if (!(update->type & REF_ISPACKED) ||
 			    update->type & REF_ISSYMREF) {
 				/* It is a loose reference. */
-				if (unlink_or_msg(git_path("%s", lock->ref_name), err)) {
+				strbuf_reset(&sb);
+				files_ref_path(refs, &sb, lock->ref_name);
+				if (unlink_or_msg(sb.buf, err)) {
 					ret = TRANSACTION_GENERIC_ERROR;
 					goto cleanup;
 				}
@@ -3825,14 +3059,17 @@
 
 	/* Delete the reflogs of any references that were deleted: */
 	for_each_string_list_item(ref_to_delete, &refs_to_delete) {
-		if (!unlink_or_warn(git_path("logs/%s", ref_to_delete->string)))
-			try_remove_empty_parents(ref_to_delete->string,
+		strbuf_reset(&sb);
+		files_reflog_path(refs, &sb, ref_to_delete->string);
+		if (!unlink_or_warn(sb.buf))
+			try_remove_empty_parents(refs, ref_to_delete->string,
 						 REMOVE_EMPTY_PARENTS_REFLOG);
 	}
 
 	clear_loose_ref_cache(refs);
 
 cleanup:
+	strbuf_release(&sb);
 	transaction->state = REF_TRANSACTION_CLOSED;
 
 	for (i = 0; i < transaction->nr; i++) {
@@ -3849,7 +3086,7 @@
 			 * can only work because we have already
 			 * removed the lockfile.)
 			 */
-			try_remove_empty_parents(update->refname,
+			try_remove_empty_parents(refs, update->refname,
 						 REMOVE_EMPTY_PARENTS_REF);
 		}
 	}
@@ -3874,7 +3111,8 @@
 					    struct strbuf *err)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "initial_ref_transaction_commit");
+		files_downcast(ref_store, REF_STORE_WRITE,
+			       "initial_ref_transaction_commit");
 	int ret = 0, i;
 	struct string_list affected_refnames = STRING_LIST_INIT_NODUP;
 
@@ -3905,7 +3143,8 @@
 	 * so here we really only check that none of the references
 	 * that we are creating already exists.
 	 */
-	if (for_each_rawref(ref_present, &affected_refnames))
+	if (refs_for_each_rawref(&refs->base, ref_present,
+				 &affected_refnames))
 		die("BUG: initial ref transaction called with existing refs");
 
 	for (i = 0; i < transaction->nr; i++) {
@@ -3914,9 +3153,9 @@
 		if ((update->flags & REF_HAVE_OLD) &&
 		    !is_null_sha1(update->old_sha1))
 			die("BUG: initial ref transaction with old_sha1 set");
-		if (verify_refname_available(update->refname,
-					     &affected_refnames, NULL,
-					     err)) {
+		if (refs_verify_refname_available(&refs->base, update->refname,
+						  &affected_refnames, NULL,
+						  err)) {
 			ret = TRANSACTION_NAME_CONFLICT;
 			goto cleanup;
 		}
@@ -3996,10 +3235,11 @@
 			       void *policy_cb_data)
 {
 	struct files_ref_store *refs =
-		files_downcast(ref_store, 0, "reflog_expire");
+		files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
 	static struct lock_file reflog_lock;
 	struct expire_reflog_cb cb;
 	struct ref_lock *lock;
+	struct strbuf log_file_sb = STRBUF_INIT;
 	char *log_file;
 	int status = 0;
 	int type;
@@ -4023,12 +3263,13 @@
 		strbuf_release(&err);
 		return -1;
 	}
-	if (!reflog_exists(refname)) {
+	if (!refs_reflog_exists(ref_store, refname)) {
 		unlock_ref(lock);
 		return 0;
 	}
 
-	log_file = git_pathdup("logs/%s", refname);
+	files_reflog_path(refs, &log_file_sb, refname);
+	log_file = strbuf_detach(&log_file_sb, NULL);
 	if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
 		/*
 		 * Even though holding $GIT_DIR/logs/$reflog.lock has
@@ -4053,7 +3294,7 @@
 	}
 
 	(*prepare_fn)(refname, sha1, cb.policy_cb);
-	for_each_reflog_ent(refname, expire_reflog_ent, &cb);
+	refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
 	(*cleanup_fn)(cb.policy_cb);
 
 	if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
@@ -4099,18 +3340,21 @@
 
 static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
 {
-	/* Check validity (but we don't need the result): */
-	files_downcast(ref_store, 0, "init_db");
+	struct files_ref_store *refs =
+		files_downcast(ref_store, REF_STORE_WRITE, "init_db");
+	struct strbuf sb = STRBUF_INIT;
 
 	/*
 	 * Create .git/refs/{heads,tags}
 	 */
-	safe_create_dir(git_path("refs/heads"), 1);
-	safe_create_dir(git_path("refs/tags"), 1);
-	if (get_shared_repository()) {
-		adjust_shared_perm(git_path("refs/heads"));
-		adjust_shared_perm(git_path("refs/tags"));
-	}
+	files_ref_path(refs, &sb, "refs/heads");
+	safe_create_dir(sb.buf, 1);
+
+	strbuf_reset(&sb);
+	files_ref_path(refs, &sb, "refs/tags");
+	safe_create_dir(sb.buf, 1);
+
+	strbuf_release(&sb);
 	return 0;
 }
 
@@ -4130,7 +3374,6 @@
 
 	files_ref_iterator_begin,
 	files_read_raw_ref,
-	files_verify_refname_available,
 
 	files_reflog_iterator_begin,
 	files_for_each_reflog_ent,
diff --git a/refs/ref-cache.c b/refs/ref-cache.c
new file mode 100644
index 0000000..6059362
--- /dev/null
+++ b/refs/ref-cache.c
@@ -0,0 +1,523 @@
+#include "../cache.h"
+#include "../refs.h"
+#include "refs-internal.h"
+#include "ref-cache.h"
+#include "../iterator.h"
+
+void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry)
+{
+	ALLOC_GROW(dir->entries, dir->nr + 1, dir->alloc);
+	dir->entries[dir->nr++] = entry;
+	/* optimize for the case that entries are added in order */
+	if (dir->nr == 1 ||
+	    (dir->nr == dir->sorted + 1 &&
+	     strcmp(dir->entries[dir->nr - 2]->name,
+		    dir->entries[dir->nr - 1]->name) < 0))
+		dir->sorted = dir->nr;
+}
+
+struct ref_dir *get_ref_dir(struct ref_entry *entry)
+{
+	struct ref_dir *dir;
+	assert(entry->flag & REF_DIR);
+	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");
+
+		dir->cache->fill_ref_dir(dir->cache->ref_store, dir, entry->name);
+		entry->flag &= ~REF_INCOMPLETE;
+	}
+	return dir;
+}
+
+struct ref_entry *create_ref_entry(const char *refname,
+				   const unsigned char *sha1, int flag,
+				   int check_name)
+{
+	struct ref_entry *ref;
+
+	if (check_name &&
+	    check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
+		die("Reference has invalid format: '%s'", refname);
+	FLEX_ALLOC_STR(ref, name, refname);
+	hashcpy(ref->u.value.oid.hash, sha1);
+	oidclr(&ref->u.value.peeled);
+	ref->flag = flag;
+	return ref;
+}
+
+struct ref_cache *create_ref_cache(struct ref_store *refs,
+				   fill_ref_dir_fn *fill_ref_dir)
+{
+	struct ref_cache *ret = xcalloc(1, sizeof(*ret));
+
+	ret->ref_store = refs;
+	ret->fill_ref_dir = fill_ref_dir;
+	ret->root = create_dir_entry(ret, "", 0, 1);
+	return ret;
+}
+
+static void clear_ref_dir(struct ref_dir *dir);
+
+static void free_ref_entry(struct ref_entry *entry)
+{
+	if (entry->flag & REF_DIR) {
+		/*
+		 * Do not use get_ref_dir() here, as that might
+		 * trigger the reading of loose refs.
+		 */
+		clear_ref_dir(&entry->u.subdir);
+	}
+	free(entry);
+}
+
+void free_ref_cache(struct ref_cache *cache)
+{
+	free_ref_entry(cache->root);
+	free(cache);
+}
+
+/*
+ * Clear and free all entries in dir, recursively.
+ */
+static void clear_ref_dir(struct ref_dir *dir)
+{
+	int i;
+	for (i = 0; i < dir->nr; i++)
+		free_ref_entry(dir->entries[i]);
+	free(dir->entries);
+	dir->sorted = dir->nr = dir->alloc = 0;
+	dir->entries = NULL;
+}
+
+struct ref_entry *create_dir_entry(struct ref_cache *cache,
+				   const char *dirname, size_t len,
+				   int incomplete)
+{
+	struct ref_entry *direntry;
+
+	FLEX_ALLOC_MEM(direntry, name, dirname, len);
+	direntry->u.subdir.cache = cache;
+	direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
+	return direntry;
+}
+
+static int ref_entry_cmp(const void *a, const void *b)
+{
+	struct ref_entry *one = *(struct ref_entry **)a;
+	struct ref_entry *two = *(struct ref_entry **)b;
+	return strcmp(one->name, two->name);
+}
+
+static void sort_ref_dir(struct ref_dir *dir);
+
+struct string_slice {
+	size_t len;
+	const char *str;
+};
+
+static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
+{
+	const struct string_slice *key = key_;
+	const struct ref_entry *ent = *(const struct ref_entry * const *)ent_;
+	int cmp = strncmp(key->str, ent->name, key->len);
+	if (cmp)
+		return cmp;
+	return '\0' - (unsigned char)ent->name[key->len];
+}
+
+int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len)
+{
+	struct ref_entry **r;
+	struct string_slice key;
+
+	if (refname == NULL || !dir->nr)
+		return -1;
+
+	sort_ref_dir(dir);
+	key.len = len;
+	key.str = refname;
+	r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
+		    ref_entry_cmp_sslice);
+
+	if (r == NULL)
+		return -1;
+
+	return r - dir->entries;
+}
+
+/*
+ * Search for a directory entry directly within dir (without
+ * recursing).  Sort dir if necessary.  subdirname must be a directory
+ * name (i.e., end in '/').  If mkdir is set, then create the
+ * directory if it is missing; otherwise, return NULL if the desired
+ * directory cannot be found.  dir must already be complete.
+ */
+static struct ref_dir *search_for_subdir(struct ref_dir *dir,
+					 const char *subdirname, size_t len,
+					 int mkdir)
+{
+	int entry_index = search_ref_dir(dir, subdirname, len);
+	struct ref_entry *entry;
+	if (entry_index == -1) {
+		if (!mkdir)
+			return NULL;
+		/*
+		 * Since dir is complete, the absence of a subdir
+		 * means that the subdir really doesn't exist;
+		 * therefore, create an empty record for it but mark
+		 * the record complete.
+		 */
+		entry = create_dir_entry(dir->cache, subdirname, len, 0);
+		add_entry_to_dir(dir, entry);
+	} else {
+		entry = dir->entries[entry_index];
+	}
+	return get_ref_dir(entry);
+}
+
+/*
+ * If refname is a reference name, find the ref_dir within the dir
+ * tree that should hold refname. If refname is a directory name
+ * (i.e., it ends in '/'), then return that ref_dir itself. dir must
+ * represent the top-level directory and must already be complete.
+ * Sort ref_dirs and recurse into subdirectories as necessary. If
+ * mkdir is set, then create any missing directories; otherwise,
+ * return NULL if the desired directory cannot be found.
+ */
+static struct ref_dir *find_containing_dir(struct ref_dir *dir,
+					   const char *refname, int mkdir)
+{
+	const char *slash;
+	for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
+		size_t dirnamelen = slash - refname + 1;
+		struct ref_dir *subdir;
+		subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
+		if (!subdir) {
+			dir = NULL;
+			break;
+		}
+		dir = subdir;
+	}
+
+	return dir;
+}
+
+struct ref_entry *find_ref_entry(struct ref_dir *dir, const char *refname)
+{
+	int entry_index;
+	struct ref_entry *entry;
+	dir = find_containing_dir(dir, refname, 0);
+	if (!dir)
+		return NULL;
+	entry_index = search_ref_dir(dir, refname, strlen(refname));
+	if (entry_index == -1)
+		return NULL;
+	entry = dir->entries[entry_index];
+	return (entry->flag & REF_DIR) ? NULL : entry;
+}
+
+int remove_entry_from_dir(struct ref_dir *dir, const char *refname)
+{
+	int refname_len = strlen(refname);
+	int entry_index;
+	struct ref_entry *entry;
+	int is_dir = refname[refname_len - 1] == '/';
+	if (is_dir) {
+		/*
+		 * refname represents a reference directory.  Remove
+		 * the trailing slash; otherwise we will get the
+		 * directory *representing* refname rather than the
+		 * one *containing* it.
+		 */
+		char *dirname = xmemdupz(refname, refname_len - 1);
+		dir = find_containing_dir(dir, dirname, 0);
+		free(dirname);
+	} else {
+		dir = find_containing_dir(dir, refname, 0);
+	}
+	if (!dir)
+		return -1;
+	entry_index = search_ref_dir(dir, refname, refname_len);
+	if (entry_index == -1)
+		return -1;
+	entry = dir->entries[entry_index];
+
+	memmove(&dir->entries[entry_index],
+		&dir->entries[entry_index + 1],
+		(dir->nr - entry_index - 1) * sizeof(*dir->entries)
+		);
+	dir->nr--;
+	if (dir->sorted > entry_index)
+		dir->sorted--;
+	free_ref_entry(entry);
+	return dir->nr;
+}
+
+int add_ref_entry(struct ref_dir *dir, struct ref_entry *ref)
+{
+	dir = find_containing_dir(dir, ref->name, 1);
+	if (!dir)
+		return -1;
+	add_entry_to_dir(dir, ref);
+	return 0;
+}
+
+/*
+ * Emit a warning and return true iff ref1 and ref2 have the same name
+ * and the same sha1.  Die if they have the same name but different
+ * sha1s.
+ */
+static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
+{
+	if (strcmp(ref1->name, ref2->name))
+		return 0;
+
+	/* Duplicate name; make sure that they don't conflict: */
+
+	if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
+		/* This is impossible by construction */
+		die("Reference directory conflict: %s", ref1->name);
+
+	if (oidcmp(&ref1->u.value.oid, &ref2->u.value.oid))
+		die("Duplicated ref, and SHA1s don't match: %s", ref1->name);
+
+	warning("Duplicated ref: %s", ref1->name);
+	return 1;
+}
+
+/*
+ * Sort the entries in dir non-recursively (if they are not already
+ * sorted) and remove any duplicate entries.
+ */
+static void sort_ref_dir(struct ref_dir *dir)
+{
+	int i, j;
+	struct ref_entry *last = NULL;
+
+	/*
+	 * This check also prevents passing a zero-length array to qsort(),
+	 * which is a problem on some platforms.
+	 */
+	if (dir->sorted == dir->nr)
+		return;
+
+	QSORT(dir->entries, dir->nr, ref_entry_cmp);
+
+	/* Remove any duplicates: */
+	for (i = 0, j = 0; j < dir->nr; j++) {
+		struct ref_entry *entry = dir->entries[j];
+		if (last && is_dup_ref(last, entry))
+			free_ref_entry(entry);
+		else
+			last = dir->entries[i++] = entry;
+	}
+	dir->sorted = dir->nr = i;
+}
+
+/*
+ * Load all of the refs from `dir` (recursively) into our in-memory
+ * cache.
+ */
+static void prime_ref_dir(struct ref_dir *dir)
+{
+	/*
+	 * The hard work of loading loose refs is done by get_ref_dir(), so we
+	 * just need to recurse through all of the sub-directories. We do not
+	 * even need to care about sorting, as traversal order does not matter
+	 * to us.
+	 */
+	int i;
+	for (i = 0; i < dir->nr; i++) {
+		struct ref_entry *entry = dir->entries[i];
+		if (entry->flag & REF_DIR)
+			prime_ref_dir(get_ref_dir(entry));
+	}
+}
+
+/*
+ * A level in the reference hierarchy that is currently being iterated
+ * through.
+ */
+struct cache_ref_iterator_level {
+	/*
+	 * The ref_dir being iterated over at this level. The ref_dir
+	 * is sorted before being stored here.
+	 */
+	struct ref_dir *dir;
+
+	/*
+	 * The index of the current entry within dir (which might
+	 * itself be a directory). If index == -1, then the iteration
+	 * hasn't yet begun. If index == dir->nr, then the iteration
+	 * through this level is over.
+	 */
+	int index;
+};
+
+/*
+ * Represent an iteration through a ref_dir in the memory cache. The
+ * iteration recurses through subdirectories.
+ */
+struct cache_ref_iterator {
+	struct ref_iterator base;
+
+	/*
+	 * The number of levels currently on the stack. This is always
+	 * at least 1, because when it becomes zero the iteration is
+	 * ended and this struct is freed.
+	 */
+	size_t levels_nr;
+
+	/* The number of levels that have been allocated on the stack */
+	size_t levels_alloc;
+
+	/*
+	 * A stack of levels. levels[0] is the uppermost level that is
+	 * being iterated over in this iteration. (This is not
+	 * necessary the top level in the references hierarchy. If we
+	 * are iterating through a subtree, then levels[0] will hold
+	 * the ref_dir for that subtree, and subsequent levels will go
+	 * on from there.)
+	 */
+	struct cache_ref_iterator_level *levels;
+};
+
+static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
+{
+	struct cache_ref_iterator *iter =
+		(struct cache_ref_iterator *)ref_iterator;
+
+	while (1) {
+		struct cache_ref_iterator_level *level =
+			&iter->levels[iter->levels_nr - 1];
+		struct ref_dir *dir = level->dir;
+		struct ref_entry *entry;
+
+		if (level->index == -1)
+			sort_ref_dir(dir);
+
+		if (++level->index == level->dir->nr) {
+			/* This level is exhausted; pop up a level */
+			if (--iter->levels_nr == 0)
+				return ref_iterator_abort(ref_iterator);
+
+			continue;
+		}
+
+		entry = dir->entries[level->index];
+
+		if (entry->flag & REF_DIR) {
+			/* push down a level */
+			ALLOC_GROW(iter->levels, iter->levels_nr + 1,
+				   iter->levels_alloc);
+
+			level = &iter->levels[iter->levels_nr++];
+			level->dir = get_ref_dir(entry);
+			level->index = -1;
+		} else {
+			iter->base.refname = entry->name;
+			iter->base.oid = &entry->u.value.oid;
+			iter->base.flags = entry->flag;
+			return ITER_OK;
+		}
+	}
+}
+
+enum peel_status peel_entry(struct ref_entry *entry, int repeel)
+{
+	enum peel_status status;
+
+	if (entry->flag & REF_KNOWS_PEELED) {
+		if (repeel) {
+			entry->flag &= ~REF_KNOWS_PEELED;
+			oidclr(&entry->u.value.peeled);
+		} else {
+			return is_null_oid(&entry->u.value.peeled) ?
+				PEEL_NON_TAG : PEEL_PEELED;
+		}
+	}
+	if (entry->flag & REF_ISBROKEN)
+		return PEEL_BROKEN;
+	if (entry->flag & REF_ISSYMREF)
+		return PEEL_IS_SYMREF;
+
+	status = peel_object(entry->u.value.oid.hash, entry->u.value.peeled.hash);
+	if (status == PEEL_PEELED || status == PEEL_NON_TAG)
+		entry->flag |= REF_KNOWS_PEELED;
+	return status;
+}
+
+static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
+				   struct object_id *peeled)
+{
+	struct cache_ref_iterator *iter =
+		(struct cache_ref_iterator *)ref_iterator;
+	struct cache_ref_iterator_level *level;
+	struct ref_entry *entry;
+
+	level = &iter->levels[iter->levels_nr - 1];
+
+	if (level->index == -1)
+		die("BUG: peel called before advance for cache iterator");
+
+	entry = level->dir->entries[level->index];
+
+	if (peel_entry(entry, 0))
+		return -1;
+	oidcpy(peeled, &entry->u.value.peeled);
+	return 0;
+}
+
+static int cache_ref_iterator_abort(struct ref_iterator *ref_iterator)
+{
+	struct cache_ref_iterator *iter =
+		(struct cache_ref_iterator *)ref_iterator;
+
+	free(iter->levels);
+	base_ref_iterator_free(ref_iterator);
+	return ITER_DONE;
+}
+
+static struct ref_iterator_vtable cache_ref_iterator_vtable = {
+	cache_ref_iterator_advance,
+	cache_ref_iterator_peel,
+	cache_ref_iterator_abort
+};
+
+struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache,
+					      const char *prefix,
+					      int prime_dir)
+{
+	struct ref_dir *dir;
+	struct cache_ref_iterator *iter;
+	struct ref_iterator *ref_iterator;
+	struct cache_ref_iterator_level *level;
+
+	dir = get_ref_dir(cache->root);
+	if (prefix && *prefix)
+		dir = find_containing_dir(dir, prefix, 0);
+	if (!dir)
+		/* There's nothing to iterate over. */
+		return  empty_ref_iterator_begin();
+
+	if (prime_dir)
+		prime_ref_dir(dir);
+
+	iter = xcalloc(1, sizeof(*iter));
+	ref_iterator = &iter->base;
+	base_ref_iterator_init(ref_iterator, &cache_ref_iterator_vtable);
+	ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
+
+	iter->levels_nr = 1;
+	level = &iter->levels[0];
+	level->index = -1;
+	level->dir = dir;
+
+	if (prefix && *prefix)
+		ref_iterator = prefix_ref_iterator_begin(ref_iterator,
+							 prefix, 0);
+
+	return ref_iterator;
+}
diff --git a/refs/ref-cache.h b/refs/ref-cache.h
new file mode 100644
index 0000000..ffdc54f
--- /dev/null
+++ b/refs/ref-cache.h
@@ -0,0 +1,267 @@
+#ifndef REFS_REF_CACHE_H
+#define REFS_REF_CACHE_H
+
+struct ref_dir;
+
+/*
+ * If this ref_cache is filled lazily, this function is used to load
+ * information into the specified ref_dir (shallow or deep, at the
+ * option of the ref_store). dirname includes a trailing slash.
+ */
+typedef void fill_ref_dir_fn(struct ref_store *ref_store,
+			     struct ref_dir *dir, const char *dirname);
+
+struct ref_cache {
+	struct ref_entry *root;
+
+	/* A pointer to the ref_store whose cache this is: */
+	struct ref_store *ref_store;
+
+	/*
+	 * Function used (if necessary) to lazily-fill cache. May be
+	 * NULL.
+	 */
+	fill_ref_dir_fn *fill_ref_dir;
+};
+
+/*
+ * Information used (along with the information in ref_entry) to
+ * describe a single cached reference.  This data structure only
+ * occurs embedded in a union in struct ref_entry, and only when
+ * (ref_entry->flag & REF_DIR) is zero.
+ */
+struct ref_value {
+	/*
+	 * The name of the object to which this reference resolves
+	 * (which may be a tag object).  If REF_ISBROKEN, this is
+	 * null.  If REF_ISSYMREF, then this is the name of the object
+	 * referred to by the last reference in the symlink chain.
+	 */
+	struct object_id oid;
+
+	/*
+	 * If REF_KNOWS_PEELED, then this field holds the peeled value
+	 * of this reference, or null if the reference is known not to
+	 * be peelable.  See the documentation for peel_ref() for an
+	 * exact definition of "peelable".
+	 */
+	struct object_id peeled;
+};
+
+/*
+ * Information used (along with the information in ref_entry) to
+ * describe a level in the hierarchy of references.  This data
+ * structure only occurs embedded in a union in struct ref_entry, and
+ * only when (ref_entry.flag & REF_DIR) is set.  In that case,
+ * (ref_entry.flag & REF_INCOMPLETE) determines whether the references
+ * in the directory have already been read:
+ *
+ *     (ref_entry.flag & REF_INCOMPLETE) unset -- a directory of loose
+ *         or packed references, already read.
+ *
+ *     (ref_entry.flag & REF_INCOMPLETE) set -- a directory of loose
+ *         references that hasn't been read yet (nor has any of its
+ *         subdirectories).
+ *
+ * Entries within a directory are stored within a growable array of
+ * pointers to ref_entries (entries, nr, alloc).  Entries 0 <= i <
+ * sorted are sorted by their component name in strcmp() order and the
+ * remaining entries are unsorted.
+ *
+ * Loose references are read lazily, one directory at a time.  When a
+ * directory of loose references is read, then all of the references
+ * in that directory are stored, and REF_INCOMPLETE stubs are created
+ * for any subdirectories, but the subdirectories themselves are not
+ * read.  The reading is triggered by get_ref_dir().
+ */
+struct ref_dir {
+	int nr, alloc;
+
+	/*
+	 * Entries with index 0 <= i < sorted are sorted by name.  New
+	 * entries are appended to the list unsorted, and are sorted
+	 * only when required; thus we avoid the need to sort the list
+	 * after the addition of every reference.
+	 */
+	int sorted;
+
+	/* The ref_cache containing this entry: */
+	struct ref_cache *cache;
+
+	struct ref_entry **entries;
+};
+
+/*
+ * Bit values for ref_entry::flag.  REF_ISSYMREF=0x01,
+ * REF_ISPACKED=0x02, REF_ISBROKEN=0x04 and REF_BAD_NAME=0x08 are
+ * public values; see refs.h.
+ */
+
+/*
+ * The field ref_entry->u.value.peeled of this value entry contains
+ * the correct peeled value for the reference, which might be
+ * null_sha1 if the reference is not a tag or if it is broken.
+ */
+#define REF_KNOWS_PEELED 0x10
+
+/* ref_entry represents a directory of references */
+#define REF_DIR 0x20
+
+/*
+ * Entry has not yet been read from disk (used only for REF_DIR
+ * entries representing loose references)
+ */
+#define REF_INCOMPLETE 0x40
+
+/*
+ * A ref_entry represents either a reference or a "subdirectory" of
+ * references.
+ *
+ * Each directory in the reference namespace is represented by a
+ * ref_entry with (flags & REF_DIR) set and containing a subdir member
+ * that holds the entries in that directory that have been read so
+ * far.  If (flags & REF_INCOMPLETE) is set, then the directory and
+ * its subdirectories haven't been read yet.  REF_INCOMPLETE is only
+ * used for loose reference directories.
+ *
+ * References are represented by a ref_entry with (flags & REF_DIR)
+ * unset and a value member that describes the reference's value.  The
+ * flag member is at the ref_entry level, but it is also needed to
+ * interpret the contents of the value field (in other words, a
+ * ref_value object is not very much use without the enclosing
+ * ref_entry).
+ *
+ * Reference names cannot end with slash and directories' names are
+ * always stored with a trailing slash (except for the top-level
+ * directory, which is always denoted by "").  This has two nice
+ * consequences: (1) when the entries in each subdir are sorted
+ * lexicographically by name (as they usually are), the references in
+ * a whole tree can be generated in lexicographic order by traversing
+ * the tree in left-to-right, depth-first order; (2) the names of
+ * references and subdirectories cannot conflict, and therefore the
+ * presence of an empty subdirectory does not block the creation of a
+ * similarly-named reference.  (The fact that reference names with the
+ * same leading components can conflict *with each other* is a
+ * separate issue that is regulated by refs_verify_refname_available().)
+ *
+ * Please note that the name field contains the fully-qualified
+ * reference (or subdirectory) name.  Space could be saved by only
+ * storing the relative names.  But that would require the full names
+ * to be generated on the fly when iterating in do_for_each_ref(), and
+ * would break callback functions, who have always been able to assume
+ * that the name strings that they are passed will not be freed during
+ * the iteration.
+ */
+struct ref_entry {
+	unsigned char flag; /* ISSYMREF? ISPACKED? */
+	union {
+		struct ref_value value; /* if not (flags&REF_DIR) */
+		struct ref_dir subdir; /* if (flags&REF_DIR) */
+	} u;
+	/*
+	 * The full name of the reference (e.g., "refs/heads/master")
+	 * or the full name of the directory with a trailing slash
+	 * (e.g., "refs/heads/"):
+	 */
+	char name[FLEX_ARRAY];
+};
+
+/*
+ * Return the index of the entry with the given refname from the
+ * ref_dir (non-recursively), sorting dir if necessary.  Return -1 if
+ * no such entry is found.  dir must already be complete.
+ */
+int search_ref_dir(struct ref_dir *dir, const char *refname, size_t len);
+
+struct ref_dir *get_ref_dir(struct ref_entry *entry);
+
+/*
+ * Create a struct ref_entry object for the specified dirname.
+ * dirname is the name of the directory with a trailing slash (e.g.,
+ * "refs/heads/") or "" for the top-level directory.
+ */
+struct ref_entry *create_dir_entry(struct ref_cache *cache,
+				   const char *dirname, size_t len,
+				   int incomplete);
+
+struct ref_entry *create_ref_entry(const char *refname,
+				   const unsigned char *sha1, int flag,
+				   int check_name);
+
+/*
+ * Return a pointer to a new `ref_cache`. Its top-level starts out
+ * marked incomplete. If `fill_ref_dir` is non-NULL, it is the
+ * function called to fill in incomplete directories in the
+ * `ref_cache` when they are accessed. If it is NULL, then the whole
+ * `ref_cache` must be filled (including clearing its directories'
+ * `REF_INCOMPLETE` bits) before it is used.
+ */
+struct ref_cache *create_ref_cache(struct ref_store *refs,
+				   fill_ref_dir_fn *fill_ref_dir);
+
+/*
+ * Free the `ref_cache` and all of its associated data.
+ */
+void free_ref_cache(struct ref_cache *cache);
+
+/*
+ * Add a ref_entry to the end of dir (unsorted).  Entry is always
+ * stored directly in dir; no recursion into subdirectories is
+ * done.
+ */
+void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
+
+/*
+ * Remove the entry with the given name from dir, recursing into
+ * subdirectories as necessary.  If refname is the name of a directory
+ * (i.e., ends with '/'), then remove the directory and its contents.
+ * If the removal was successful, return the number of entries
+ * remaining in the directory entry that contained the deleted entry.
+ * If the name was not found, return -1.  Please note that this
+ * function only deletes the entry from the cache; it does not delete
+ * it from the filesystem or ensure that other cache entries (which
+ * might be symbolic references to the removed entry) are updated.
+ * Nor does it remove any containing dir entries that might be made
+ * empty by the removal.  dir must represent the top-level directory
+ * and must already be complete.
+ */
+int remove_entry_from_dir(struct ref_dir *dir, const char *refname);
+
+/*
+ * Add a ref_entry to the ref_dir (unsorted), recursing into
+ * subdirectories as necessary.  dir must represent the top-level
+ * directory.  Return 0 on success.
+ */
+int add_ref_entry(struct ref_dir *dir, struct ref_entry *ref);
+
+/*
+ * Find the value entry with the given name in dir, sorting ref_dirs
+ * and recursing into subdirectories as necessary.  If the name is not
+ * found or it corresponds to a directory entry, return NULL.
+ */
+struct ref_entry *find_ref_entry(struct ref_dir *dir, const char *refname);
+
+/*
+ * Start iterating over references in `cache`. If `prefix` is
+ * specified, only include references whose names start with that
+ * prefix. If `prime_dir` is true, then fill any incomplete
+ * directories before beginning the iteration.
+ */
+struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache,
+					      const char *prefix,
+					      int prime_dir);
+
+/*
+ * Peel the entry (if possible) and return its new peel_status.  If
+ * repeel is true, re-peel the entry even if there is an old peeled
+ * value that is already stored in it.
+ *
+ * It is OK to call this function with a packed reference entry that
+ * might be stale and might even refer to an object that has since
+ * been garbage-collected.  In such a case, if the entry has
+ * REF_KNOWS_PEELED then leave the status unchanged and return
+ * PEEL_PEELED or PEEL_NON_TAG; otherwise, return PEEL_INVALID.
+ */
+enum peel_status peel_entry(struct ref_entry *entry, int repeel);
+
+#endif /* REFS_REF_CACHE_H */
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index fa93c9a..3d46131 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -112,28 +112,6 @@
 enum peel_status peel_object(const unsigned char *name, unsigned char *sha1);
 
 /*
- * Return 0 if a reference named refname could be created without
- * conflicting with the name of an existing reference. Otherwise,
- * return a negative value and write an explanation to err. If extras
- * is non-NULL, it is a list of additional refnames with which refname
- * is not allowed to conflict. If skip is non-NULL, ignore potential
- * conflicts with refs in skip (e.g., because they are scheduled for
- * deletion in the same operation). Behavior is undefined if the same
- * name is listed in both extras and skip.
- *
- * Two reference names conflict if one of them exactly matches the
- * leading components of the other; e.g., "foo/bar" conflicts with
- * both "foo" and with "foo/bar/baz" but not with "foo/bar" or
- * "foo/barbados".
- *
- * extras and skip must be sorted.
- */
-int verify_refname_available(const char *newname,
-			     const struct string_list *extras,
-			     const struct string_list *skip,
-			     struct strbuf *err);
-
-/*
  * Copy the reflog message msg to buf, which has been allocated sufficiently
  * large, while cleaning up the whitespaces.  Especially, convert LF to space,
  * because reflog file is one line per entry.
@@ -187,6 +165,10 @@
 	const char refname[FLEX_ARRAY];
 };
 
+int refs_read_raw_ref(struct ref_store *ref_store,
+		      const char *refname, unsigned char *sha1,
+		      struct strbuf *referent, unsigned int *type);
+
 /*
  * Add a ref_update with the specified properties to transaction, and
  * return a pointer to the new object. This function does not verify
@@ -222,16 +204,13 @@
  * as atomically as possible.  This structure is opaque to callers.
  */
 struct ref_transaction {
+	struct ref_store *ref_store;
 	struct ref_update **updates;
 	size_t alloc;
 	size_t nr;
 	enum ref_transaction_state state;
 };
 
-int files_log_ref_write(const char *refname, const unsigned char *old_sha1,
-			const unsigned char *new_sha1, const char *msg,
-			int flags, struct strbuf *err);
-
 /*
  * Check for entries in extras that are within the specified
  * directory, where dirname is a reference directory name including
@@ -256,7 +235,9 @@
  * processes (though rename_ref() catches some races that might get by
  * this check).
  */
-int rename_ref_available(const char *old_refname, const char *new_refname);
+int refs_rename_ref_available(struct ref_store *refs,
+			      const char *old_refname,
+			      const char *new_refname);
 
 /* We allow "recursive" symbolic refs. Only within reason, though */
 #define SYMREF_MAXDEPTH 5
@@ -355,6 +336,17 @@
 int is_empty_ref_iterator(struct ref_iterator *ref_iterator);
 
 /*
+ * Return an iterator that goes over each reference in `refs` for
+ * which the refname begins with prefix. If trim is non-zero, then
+ * trim that many characters off the beginning of each refname. flags
+ * can be DO_FOR_EACH_INCLUDE_BROKEN to include broken references in
+ * the iteration.
+ */
+struct ref_iterator *refs_ref_iterator_begin(
+		struct ref_store *refs,
+		const char *prefix, int trim, int flags);
+
+/*
  * A callback function used to instruct merge_ref_iterator how to
  * interleave the entries from iter0 and iter1. The function should
  * return one of the constants defined in enum iterator_selection. It
@@ -485,13 +477,19 @@
 
 /* refs backends */
 
+/* ref_store_init flags */
+#define REF_STORE_READ		(1 << 0)
+#define REF_STORE_WRITE		(1 << 1) /* can perform update operations */
+#define REF_STORE_ODB		(1 << 2) /* has access to object database */
+#define REF_STORE_MAIN		(1 << 3)
+
 /*
- * Initialize the ref_store for the specified submodule, or for the
- * main repository if submodule == NULL. These functions should call
- * base_ref_store_init() to initialize the shared part of the
- * ref_store and to record the ref_store for later lookup.
+ * Initialize the ref_store for the specified gitdir. These functions
+ * should call base_ref_store_init() to initialize the shared part of
+ * the ref_store and to record the ref_store for later lookup.
  */
-typedef struct ref_store *ref_store_init_fn(const char *submodule);
+typedef struct ref_store *ref_store_init_fn(const char *gitdir,
+					    unsigned int flags);
 
 typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
 
@@ -592,12 +590,6 @@
 			    const char *refname, unsigned char *sha1,
 			    struct strbuf *referent, unsigned int *type);
 
-typedef int verify_refname_available_fn(struct ref_store *ref_store,
-					const char *newname,
-					const struct string_list *extras,
-					const struct string_list *skip,
-					struct strbuf *err);
-
 struct ref_storage_be {
 	struct ref_storage_be *next;
 	const char *name;
@@ -614,7 +606,6 @@
 
 	ref_iterator_begin_fn *iterator_begin;
 	read_raw_ref_fn *read_raw_ref;
-	verify_refname_available_fn *verify_refname_available;
 
 	reflog_iterator_begin_fn *reflog_iterator_begin;
 	for_each_reflog_ent_fn *for_each_reflog_ent;
@@ -644,21 +635,4 @@
 void base_ref_store_init(struct ref_store *refs,
 			 const struct ref_storage_be *be);
 
-/*
- * Return the ref_store instance for the specified submodule. For the
- * main repository, use submodule==NULL; such a call cannot fail. For
- * a submodule, the submodule must exist and be a nonbare repository,
- * otherwise return NULL. If the requested reference store has not yet
- * been initialized, initialize it first.
- *
- * For backwards compatibility, submodule=="" is treated the same as
- * submodule==NULL.
- */
-struct ref_store *get_ref_store(const char *submodule);
-
-const char *resolve_ref_recursively(struct ref_store *refs,
-				    const char *refname,
-				    int resolve_flags,
-				    unsigned char *sha1, int *flags);
-
 #endif /* REFS_REFS_INTERNAL_H */
diff --git a/remote-curl.c b/remote-curl.c
index e953d06..ece4599 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -167,7 +167,7 @@
 	char *buf;
 	size_t len;
 	struct ref *refs;
-	struct sha1_array shallow;
+	struct oid_array shallow;
 	unsigned proto_git : 1;
 };
 static struct discovery *last_discovery;
@@ -234,7 +234,7 @@
 	if (d) {
 		if (d == last_discovery)
 			last_discovery = NULL;
-		free(d->shallow.sha1);
+		free(d->shallow.oid);
 		free(d->buf_alloc);
 		free_refs(d->refs);
 		free(d);
@@ -531,6 +531,12 @@
 	return err;
 }
 
+static curl_off_t xcurl_off_t(ssize_t len) {
+	if (len > maximum_signed_value_of_type(curl_off_t))
+		die("cannot handle pushes this big");
+	return (curl_off_t) len;
+}
+
 static int post_rpc(struct rpc_state *rpc)
 {
 	struct active_request_slot *slot;
@@ -614,7 +620,7 @@
 		 * and we just need to send it.
 		 */
 		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, gzip_body);
-		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE, gzip_size);
+		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE_LARGE, xcurl_off_t(gzip_size));
 
 	} else if (use_gzip && 1024 < rpc->len) {
 		/* The client backend isn't giving us compressed data so
@@ -645,7 +651,7 @@
 
 		headers = curl_slist_append(headers, "Content-Encoding: gzip");
 		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, gzip_body);
-		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE, gzip_size);
+		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE_LARGE, xcurl_off_t(gzip_size));
 
 		if (options.verbosity > 1) {
 			fprintf(stderr, "POST %s (gzip %lu to %lu bytes)\n",
@@ -658,7 +664,7 @@
 		 * more normal Content-Length approach.
 		 */
 		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, rpc->buf);
-		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE, rpc->len);
+		curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE_LARGE, xcurl_off_t(rpc->len));
 		if (options.verbosity > 1) {
 			fprintf(stderr, "POST %s (%lu bytes)\n",
 				rpc->service_name, (unsigned long)rpc->len);
diff --git a/remote.c b/remote.c
index 9f83fe2..801137c 100644
--- a/remote.c
+++ b/remote.c
@@ -630,7 +630,7 @@
 	return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 }
 
-static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
+struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 {
 	return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 }
@@ -2279,7 +2279,7 @@
 	return entry;
 }
 
-int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
+static int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
 {
 	const char *colon;
 	struct push_cas *entry;
diff --git a/remote.h b/remote.h
index dd8c517..6c28cd3 100644
--- a/remote.h
+++ b/remote.h
@@ -149,11 +149,11 @@
  */
 void free_refs(struct ref *ref);
 
-struct sha1_array;
+struct oid_array;
 extern struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
 				     struct ref **list, unsigned int flags,
-				     struct sha1_array *extra_have,
-				     struct sha1_array *shallow);
+				     struct oid_array *extra_have,
+				     struct oid_array *shallow);
 
 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);
@@ -169,6 +169,7 @@
 
 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);
 
 void free_refspec(int nr_refspec, struct refspec *refspec);
 
@@ -290,7 +291,6 @@
 };
 
 extern int parseopt_push_cas_option(const struct option *, const char *arg, int unset);
-extern int parse_push_cas_option(struct push_cas_option *, const char *arg, int unset);
 
 extern int is_empty_cas(const struct push_cas_option *);
 void apply_push_cas(struct push_cas_option *, struct remote *, struct ref *);
diff --git a/send-pack.c b/send-pack.c
index 66e652f..78bb34e 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -50,7 +50,7 @@
 /*
  * Make a pack stream and spit it out into file descriptor fd
  */
-static int pack_objects(int fd, struct ref *refs, struct sha1_array *extra, struct send_pack_args *args)
+static int pack_objects(int fd, struct ref *refs, struct oid_array *extra, struct send_pack_args *args)
 {
 	/*
 	 * The child becomes pack-objects --revs; we feed
@@ -98,7 +98,7 @@
 	 */
 	po_in = xfdopen(po.in, "w");
 	for (i = 0; i < extra->nr; i++)
-		feed_object(extra->sha1[i], po_in, 1);
+		feed_object(extra->oid[i].hash, po_in, 1);
 
 	while (refs) {
 		if (!is_null_oid(&refs->old_oid))
@@ -376,7 +376,7 @@
 int send_pack(struct send_pack_args *args,
 	      int fd[], struct child_process *conn,
 	      struct ref *remote_refs,
-	      struct sha1_array *extra_have)
+	      struct oid_array *extra_have)
 {
 	int in = fd[0];
 	int out = fd[1];
diff --git a/send-pack.h b/send-pack.h
index 67fc40f..6af71f7 100644
--- a/send-pack.h
+++ b/send-pack.h
@@ -32,6 +32,6 @@
 
 int send_pack(struct send_pack_args *args,
 	      int fd[], struct child_process *conn,
-	      struct ref *remote_refs, struct sha1_array *extra_have);
+	      struct ref *remote_refs, struct oid_array *extra_have);
 
 #endif
diff --git a/sequencer.c b/sequencer.c
index d76dc9c..10c3b4f 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -602,6 +602,12 @@
 "\n"
 "  git rebase --continue\n");
 
+#define ALLOW_EMPTY (1<<0)
+#define EDIT_MSG    (1<<1)
+#define AMEND_MSG   (1<<2)
+#define CLEANUP_MSG (1<<3)
+#define VERIFY_MSG  (1<<4)
+
 /*
  * If we are cherry-pick, and if the merge did not result in
  * hand-editing, we will hit this commit and inherit the original
@@ -615,8 +621,7 @@
  * author metadata.
  */
 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
-			  int allow_empty, int edit, int amend,
-			  int cleanup_commit_message)
+			  unsigned int flags)
 {
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	const char *value;
@@ -624,7 +629,7 @@
 	cmd.git_cmd = 1;
 
 	if (is_rebase_i(opts)) {
-		if (!edit) {
+		if (!(flags & EDIT_MSG)) {
 			cmd.stdout_to_stderr = 1;
 			cmd.err = -1;
 		}
@@ -638,9 +643,10 @@
 	}
 
 	argv_array_push(&cmd.args, "commit");
-	argv_array_push(&cmd.args, "-n");
 
-	if (amend)
+	if (!(flags & VERIFY_MSG))
+		argv_array_push(&cmd.args, "-n");
+	if ((flags & AMEND_MSG))
 		argv_array_push(&cmd.args, "--amend");
 	if (opts->gpg_sign)
 		argv_array_pushf(&cmd.args, "-S%s", opts->gpg_sign);
@@ -648,16 +654,16 @@
 		argv_array_push(&cmd.args, "-s");
 	if (defmsg)
 		argv_array_pushl(&cmd.args, "-F", defmsg, NULL);
-	if (cleanup_commit_message)
+	if ((flags & CLEANUP_MSG))
 		argv_array_push(&cmd.args, "--cleanup=strip");
-	if (edit)
+	if ((flags & EDIT_MSG))
 		argv_array_push(&cmd.args, "-e");
-	else if (!cleanup_commit_message &&
+	else if (!(flags & CLEANUP_MSG) &&
 		 !opts->signoff && !opts->record_origin &&
 		 git_config_get_value("commit.cleanup", &value))
 		argv_array_push(&cmd.args, "--cleanup=verbatim");
 
-	if (allow_empty)
+	if ((flags & ALLOW_EMPTY))
 		argv_array_push(&cmd.args, "--allow-empty");
 
 	if (opts->allow_empty_message)
@@ -926,14 +932,14 @@
 static int do_pick_commit(enum todo_command command, struct commit *commit,
 		struct replay_opts *opts, int final_fixup)
 {
-	int edit = opts->edit, cleanup_commit_message = 0;
-	const char *msg_file = edit ? NULL : git_path_merge_msg();
+	unsigned int flags = opts->edit ? EDIT_MSG : 0;
+	const char *msg_file = opts->edit ? NULL : git_path_merge_msg();
 	unsigned char head[20];
 	struct commit *base, *next, *parent;
 	const char *base_label, *next_label;
 	struct commit_message msg = { NULL, NULL, NULL, NULL };
 	struct strbuf msgbuf = STRBUF_INIT;
-	int res, unborn = 0, amend = 0, allow = 0;
+	int res, unborn = 0, allow;
 
 	if (opts->no_commit) {
 		/*
@@ -991,7 +997,9 @@
 			opts);
 		if (res || command != TODO_REWORD)
 			goto leave;
-		edit = amend = 1;
+		flags |= EDIT_MSG | AMEND_MSG;
+		if (command == TODO_REWORD)
+			flags |= VERIFY_MSG;
 		msg_file = NULL;
 		goto fast_forward_edit;
 	}
@@ -1046,25 +1054,25 @@
 	}
 
 	if (command == TODO_REWORD)
-		edit = 1;
+		flags |= EDIT_MSG | VERIFY_MSG;
 	else if (is_fixup(command)) {
 		if (update_squash_messages(command, commit, opts))
 			return -1;
-		amend = 1;
+		flags |= AMEND_MSG;
 		if (!final_fixup)
 			msg_file = rebase_path_squash_msg();
 		else if (file_exists(rebase_path_fixup_msg())) {
-			cleanup_commit_message = 1;
+			flags |= CLEANUP_MSG;
 			msg_file = rebase_path_fixup_msg();
 		} else {
-			const char *dest = git_path("SQUASH_MSG");
+			const char *dest = git_path_squash_msg();
 			unlink(dest);
 			if (copy_file(dest, rebase_path_squash_msg(), 0666))
 				return error(_("could not rename '%s' to '%s'"),
 					     rebase_path_squash_msg(), dest);
-			unlink(git_path("MERGE_MSG"));
+			unlink(git_path_merge_msg());
 			msg_file = dest;
-			edit = 1;
+			flags |= EDIT_MSG;
 		}
 	}
 
@@ -1123,11 +1131,11 @@
 	if (allow < 0) {
 		res = allow;
 		goto leave;
-	}
+	} else if (allow)
+		flags |= ALLOW_EMPTY;
 	if (!opts->no_commit)
 fast_forward_edit:
-		res = run_git_commit(msg_file, opts, allow, edit, amend,
-				     cleanup_commit_message);
+		res = run_git_commit(msg_file, opts, flags);
 
 	if (!res && final_fixup) {
 		unlink(rebase_path_fixup_msg());
@@ -1192,6 +1200,7 @@
 	struct todo_item *items;
 	int nr, alloc, current;
 	int done_nr, total_nr;
+	struct stat_data stat;
 };
 
 #define TODO_LIST_INIT { STRBUF_INIT }
@@ -1322,6 +1331,7 @@
 static int read_populate_todo(struct todo_list *todo_list,
 			struct replay_opts *opts)
 {
+	struct stat st;
 	const char *todo_file = get_todo_path(opts);
 	int fd, res;
 
@@ -1335,6 +1345,11 @@
 	}
 	close(fd);
 
+	res = stat(todo_file, &st);
+	if (res)
+		return error(_("could not stat '%s'"), todo_file);
+	fill_stat_data(&todo_list->stat, &st);
+
 	res = parse_insn_buffer(todo_list->buf.buf, todo_list);
 	if (res) {
 		if (is_rebase_i(opts))
@@ -1812,10 +1827,10 @@
 		return error(_("could not rename '%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))
+	unlink(git_path_merge_msg());
+	if (copy_file(git_path_merge_msg(), rebase_path_message(), 0666))
 		return error(_("could not copy '%s' to '%s'"),
-			     rebase_path_message(), git_path("MERGE_MSG"));
+			     rebase_path_message(), git_path_merge_msg());
 	return error_with_patch(commit, subject, subject_len, opts, 1, 0);
 }
 
@@ -2020,10 +2035,25 @@
 		} else if (item->command == TODO_EXEC) {
 			char *end_of_arg = (char *)(item->arg + item->arg_len);
 			int saved = *end_of_arg;
+			struct stat st;
 
 			*end_of_arg = '\0';
 			res = do_exec(item->arg);
 			*end_of_arg = saved;
+
+			/* Reread the todo file if it has changed. */
+			if (res)
+				; /* fall through */
+			else if (stat(get_todo_path(opts), &st))
+				res = error_errno(_("could not stat '%s'"),
+						  get_todo_path(opts));
+			else if (match_stat_data(&todo_list->stat, &st)) {
+				todo_list_release(todo_list);
+				if (read_populate_todo(todo_list, opts))
+					res = -1; /* message was printed */
+				/* `current` will be incremented below */
+				todo_list->current = -1;
+			}
 		} else if (!is_noop(item->command))
 			return error(_("unknown command %d"), item->command);
 
@@ -2154,12 +2184,12 @@
 
 static int commit_staged_changes(struct replay_opts *opts)
 {
-	int amend = 0;
+	unsigned int flags = ALLOW_EMPTY | EDIT_MSG;
 
 	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");
+		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"));
@@ -2184,10 +2214,10 @@
 				       "--continue' again."));
 
 		strbuf_release(&rev);
-		amend = 1;
+		flags |= AMEND_MSG;
 	}
 
-	if (run_git_commit(rebase_path_message(), opts, 1, 1, amend, 0))
+	if (run_git_commit(rebase_path_message(), opts, flags))
 		return error(_("could not commit staged changes."));
 	unlink(rebase_path_amend());
 	return 0;
diff --git a/server-info.c b/server-info.c
index 7bc4e75..f6c1a3d 100644
--- a/server-info.c
+++ b/server-info.c
@@ -14,19 +14,21 @@
 	char *tmp = mkpathdup("%s_XXXXXX", path);
 	int ret = -1;
 	int fd = -1;
-	FILE *fp = NULL;
+	FILE *fp = NULL, *to_close;
 
 	safe_create_leading_directories(path);
 	fd = git_mkstemp_mode(tmp, 0666);
 	if (fd < 0)
 		goto out;
-	fp = fdopen(fd, "w");
+	to_close = fp = fdopen(fd, "w");
 	if (!fp)
 		goto out;
+	fd = -1;
 	ret = generate(fp);
 	if (ret)
 		goto out;
-	if (fclose(fp))
+	fp = NULL;
+	if (fclose(to_close))
 		goto out;
 	if (adjust_shared_perm(tmp) < 0)
 		goto out;
diff --git a/setup.c b/setup.c
index 5c7946d..0309c27 100644
--- a/setup.c
+++ b/setup.c
@@ -987,7 +987,7 @@
 {
 	static struct strbuf cwd = STRBUF_INIT;
 	struct strbuf dir = STRBUF_INIT, gitdir = STRBUF_INIT;
-	const char *prefix;
+	const char *prefix, *env_prefix;
 
 	/*
 	 * We may have read an incomplete configuration before
@@ -1045,6 +1045,10 @@
 		die("BUG: unhandled setup_git_directory_1() result");
 	}
 
+	env_prefix = getenv(GIT_TOPLEVEL_PREFIX_ENVIRONMENT);
+	if (env_prefix)
+		prefix = env_prefix;
+
 	if (prefix)
 		setenv(GIT_PREFIX_ENVIRONMENT, prefix, 1);
 	else
diff --git a/sha1-array.c b/sha1-array.c
index c1cc25c..7d646ab 100644
--- a/sha1-array.c
+++ b/sha1-array.c
@@ -2,60 +2,60 @@
 #include "sha1-array.h"
 #include "sha1-lookup.h"
 
-void sha1_array_append(struct sha1_array *array, const unsigned char *sha1)
+void oid_array_append(struct oid_array *array, const struct object_id *oid)
 {
-	ALLOC_GROW(array->sha1, array->nr + 1, array->alloc);
-	hashcpy(array->sha1[array->nr++], sha1);
+	ALLOC_GROW(array->oid, array->nr + 1, array->alloc);
+	oidcpy(&array->oid[array->nr++], oid);
 	array->sorted = 0;
 }
 
 static int void_hashcmp(const void *a, const void *b)
 {
-	return hashcmp(a, b);
+	return oidcmp(a, b);
 }
 
-static void sha1_array_sort(struct sha1_array *array)
+static void oid_array_sort(struct oid_array *array)
 {
-	QSORT(array->sha1, array->nr, void_hashcmp);
+	QSORT(array->oid, array->nr, void_hashcmp);
 	array->sorted = 1;
 }
 
 static const unsigned char *sha1_access(size_t index, void *table)
 {
-	unsigned char (*array)[20] = table;
-	return array[index];
+	struct object_id *array = table;
+	return array[index].hash;
 }
 
-int sha1_array_lookup(struct sha1_array *array, const unsigned char *sha1)
+int oid_array_lookup(struct oid_array *array, const struct object_id *oid)
 {
 	if (!array->sorted)
-		sha1_array_sort(array);
-	return sha1_pos(sha1, array->sha1, array->nr, sha1_access);
+		oid_array_sort(array);
+	return sha1_pos(oid->hash, array->oid, array->nr, sha1_access);
 }
 
-void sha1_array_clear(struct sha1_array *array)
+void oid_array_clear(struct oid_array *array)
 {
-	free(array->sha1);
-	array->sha1 = NULL;
+	free(array->oid);
+	array->oid = NULL;
 	array->nr = 0;
 	array->alloc = 0;
 	array->sorted = 0;
 }
 
-int sha1_array_for_each_unique(struct sha1_array *array,
-				for_each_sha1_fn fn,
+int oid_array_for_each_unique(struct oid_array *array,
+				for_each_oid_fn fn,
 				void *data)
 {
 	int i;
 
 	if (!array->sorted)
-		sha1_array_sort(array);
+		oid_array_sort(array);
 
 	for (i = 0; i < array->nr; i++) {
 		int ret;
-		if (i > 0 && !hashcmp(array->sha1[i], array->sha1[i-1]))
+		if (i > 0 && !oidcmp(array->oid + i, array->oid + i - 1))
 			continue;
-		ret = fn(array->sha1[i], data);
+		ret = fn(array->oid + i, data);
 		if (ret)
 			return ret;
 	}
diff --git a/sha1-array.h b/sha1-array.h
index b3230be..04b0756 100644
--- a/sha1-array.h
+++ b/sha1-array.h
@@ -1,23 +1,23 @@
 #ifndef SHA1_ARRAY_H
 #define SHA1_ARRAY_H
 
-struct sha1_array {
-	unsigned char (*sha1)[20];
+struct oid_array {
+	struct object_id *oid;
 	int nr;
 	int alloc;
 	int sorted;
 };
 
-#define SHA1_ARRAY_INIT { NULL, 0, 0, 0 }
+#define OID_ARRAY_INIT { NULL, 0, 0, 0 }
 
-void sha1_array_append(struct sha1_array *array, const unsigned char *sha1);
-int sha1_array_lookup(struct sha1_array *array, const unsigned char *sha1);
-void sha1_array_clear(struct sha1_array *array);
+void oid_array_append(struct oid_array *array, const struct object_id *oid);
+int oid_array_lookup(struct oid_array *array, const struct object_id *oid);
+void oid_array_clear(struct oid_array *array);
 
-typedef int (*for_each_sha1_fn)(const unsigned char sha1[20],
-				void *data);
-int sha1_array_for_each_unique(struct sha1_array *array,
-			       for_each_sha1_fn fn,
+typedef int (*for_each_oid_fn)(const struct object_id *oid,
+			       void *data);
+int oid_array_for_each_unique(struct oid_array *array,
+			       for_each_oid_fn fn,
 			       void *data);
 
 #endif /* SHA1_ARRAY_H */
diff --git a/sha1_file.c b/sha1_file.c
index 7106389..59a4ed2 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1606,7 +1606,7 @@
 		if (!hashcmp(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i))
 			return;
 	p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
-				      st_mult(GIT_SHA1_RAWSZ,
+				      st_mult(GIT_MAX_RAWSZ,
 					      st_add(p->num_bad_objects, 1)));
 	hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1);
 	p->num_bad_objects++;
@@ -2952,7 +2952,7 @@
 	if (status && oi->typep)
 		*oi->typep = status;
 	strbuf_release(&hdrbuf);
-	return 0;
+	return (status < 0) ? status : 0;
 }
 
 int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
@@ -3481,6 +3481,8 @@
 {
 	struct pack_entry e;
 
+	if (!startup_info->have_repository)
+		return 0;
 	if (find_pack_entry(sha1, &e))
 		return 1;
 	if (has_loose_object(sha1))
@@ -3759,11 +3761,11 @@
 		strbuf_addf(path, "/%s", de->d_name);
 
 		if (strlen(de->d_name) == GIT_SHA1_HEXSZ - 2)  {
-			char hex[GIT_SHA1_HEXSZ+1];
+			char hex[GIT_MAX_HEXSZ+1];
 			struct object_id oid;
 
-			snprintf(hex, sizeof(hex), "%02x%s",
-				 subdir_nr, de->d_name);
+			xsnprintf(hex, sizeof(hex), "%02x%s",
+				  subdir_nr, de->d_name);
 			if (!get_oid_hex(hex, &oid)) {
 				if (obj_cb) {
 					r = obj_cb(&oid, path->buf, data);
@@ -3913,7 +3915,7 @@
 			     const unsigned char *expected_sha1)
 {
 	git_SHA_CTX c;
-	unsigned char real_sha1[GIT_SHA1_RAWSZ];
+	unsigned char real_sha1[GIT_MAX_RAWSZ];
 	unsigned char buf[4096];
 	unsigned long total_read;
 	int status = Z_OK;
@@ -3970,7 +3972,6 @@
 		      void **contents)
 {
 	int ret = -1;
-	int fd = -1;
 	void *map = NULL;
 	unsigned long mapsize;
 	git_zstream stream;
@@ -4020,7 +4021,5 @@
 out:
 	if (map)
 		munmap(map, mapsize);
-	if (fd >= 0)
-		close(fd);
 	return ret;
 }
diff --git a/sha1_name.c b/sha1_name.c
index cda9e49..8eec9f7 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -11,16 +11,16 @@
 
 static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
 
-typedef int (*disambiguate_hint_fn)(const unsigned char *, void *);
+typedef int (*disambiguate_hint_fn)(const struct object_id *, void *);
 
 struct disambiguate_state {
 	int len; /* length of prefix in hex chars */
-	char hex_pfx[GIT_SHA1_HEXSZ + 1];
-	unsigned char bin_pfx[GIT_SHA1_RAWSZ];
+	char hex_pfx[GIT_MAX_HEXSZ + 1];
+	struct object_id bin_pfx;
 
 	disambiguate_hint_fn fn;
 	void *cb_data;
-	unsigned char candidate[GIT_SHA1_RAWSZ];
+	struct object_id candidate;
 	unsigned candidate_exists:1;
 	unsigned candidate_checked:1;
 	unsigned candidate_ok:1;
@@ -29,7 +29,7 @@
 	unsigned always_call_fn:1;
 };
 
-static void update_candidates(struct disambiguate_state *ds, const unsigned char *current)
+static void update_candidates(struct disambiguate_state *ds, const struct object_id *current)
 {
 	if (ds->always_call_fn) {
 		ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
@@ -37,10 +37,10 @@
 	}
 	if (!ds->candidate_exists) {
 		/* this is the first candidate */
-		hashcpy(ds->candidate, current);
+		oidcpy(&ds->candidate, current);
 		ds->candidate_exists = 1;
 		return;
-	} else if (!hashcmp(ds->candidate, current)) {
+	} else if (!oidcmp(&ds->candidate, current)) {
 		/* the same as what we already have seen */
 		return;
 	}
@@ -52,14 +52,14 @@
 	}
 
 	if (!ds->candidate_checked) {
-		ds->candidate_ok = ds->fn(ds->candidate, ds->cb_data);
+		ds->candidate_ok = ds->fn(&ds->candidate, ds->cb_data);
 		ds->disambiguate_fn_used = 1;
 		ds->candidate_checked = 1;
 	}
 
 	if (!ds->candidate_ok) {
 		/* discard the candidate; we know it does not satisfy fn */
-		hashcpy(ds->candidate, current);
+		oidcpy(&ds->candidate, current);
 		ds->candidate_checked = 0;
 		return;
 	}
@@ -80,7 +80,7 @@
 static void find_short_object_filename(struct disambiguate_state *ds)
 {
 	struct alternate_object_database *alt;
-	char hex[GIT_SHA1_HEXSZ];
+	char hex[GIT_MAX_HEXSZ];
 	static struct alternate_object_database *fakeent;
 
 	if (!fakeent) {
@@ -107,15 +107,15 @@
 			continue;
 
 		while (!ds->ambiguous && (de = readdir(dir)) != NULL) {
-			unsigned char sha1[20];
+			struct object_id oid;
 
-			if (strlen(de->d_name) != 38)
+			if (strlen(de->d_name) != GIT_SHA1_HEXSZ - 2)
 				continue;
 			if (memcmp(de->d_name, ds->hex_pfx + 2, ds->len - 2))
 				continue;
-			memcpy(hex + 2, de->d_name, 38);
-			if (!get_sha1_hex(hex, sha1))
-				update_candidates(ds, sha1);
+			memcpy(hex + 2, de->d_name, GIT_SHA1_HEXSZ - 2);
+			if (!get_oid_hex(hex, &oid))
+				update_candidates(ds, &oid);
 		}
 		closedir(dir);
 	}
@@ -140,7 +140,7 @@
 			   struct disambiguate_state *ds)
 {
 	uint32_t num, last, i, first = 0;
-	const unsigned char *current = NULL;
+	const struct object_id *current = NULL;
 
 	open_pack_index(p);
 	num = p->num_objects;
@@ -151,7 +151,7 @@
 		int cmp;
 
 		current = nth_packed_object_sha1(p, mid);
-		cmp = hashcmp(ds->bin_pfx, current);
+		cmp = hashcmp(ds->bin_pfx.hash, current);
 		if (!cmp) {
 			first = mid;
 			break;
@@ -169,8 +169,9 @@
 	 * 0, 1 or more objects that actually match(es).
 	 */
 	for (i = first; i < num && !ds->ambiguous; i++) {
-		current = nth_packed_object_sha1(p, i);
-		if (!match_sha(ds->len, ds->bin_pfx, current))
+		struct object_id oid;
+		current = nth_packed_object_oid(&oid, p, i);
+		if (!match_sha(ds->len, ds->bin_pfx.hash, current->hash))
 			break;
 		update_candidates(ds, current);
 	}
@@ -213,66 +214,66 @@
 		 * same repository!
 		 */
 		ds->candidate_ok = (!ds->disambiguate_fn_used ||
-				    ds->fn(ds->candidate, ds->cb_data));
+				    ds->fn(&ds->candidate, ds->cb_data));
 
 	if (!ds->candidate_ok)
 		return SHORT_NAME_AMBIGUOUS;
 
-	hashcpy(sha1, ds->candidate);
+	hashcpy(sha1, ds->candidate.hash);
 	return 0;
 }
 
-static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unused)
+static int disambiguate_commit_only(const struct object_id *oid, void *cb_data_unused)
 {
-	int kind = sha1_object_info(sha1, NULL);
+	int kind = sha1_object_info(oid->hash, NULL);
 	return kind == OBJ_COMMIT;
 }
 
-static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data_unused)
+static int disambiguate_committish_only(const struct object_id *oid, void *cb_data_unused)
 {
 	struct object *obj;
 	int kind;
 
-	kind = sha1_object_info(sha1, NULL);
+	kind = sha1_object_info(oid->hash, NULL);
 	if (kind == OBJ_COMMIT)
 		return 1;
 	if (kind != OBJ_TAG)
 		return 0;
 
 	/* We need to do this the hard way... */
-	obj = deref_tag(parse_object(sha1), NULL, 0);
+	obj = deref_tag(parse_object(oid->hash), NULL, 0);
 	if (obj && obj->type == OBJ_COMMIT)
 		return 1;
 	return 0;
 }
 
-static int disambiguate_tree_only(const unsigned char *sha1, void *cb_data_unused)
+static int disambiguate_tree_only(const struct object_id *oid, void *cb_data_unused)
 {
-	int kind = sha1_object_info(sha1, NULL);
+	int kind = sha1_object_info(oid->hash, NULL);
 	return kind == OBJ_TREE;
 }
 
-static int disambiguate_treeish_only(const unsigned char *sha1, void *cb_data_unused)
+static int disambiguate_treeish_only(const struct object_id *oid, void *cb_data_unused)
 {
 	struct object *obj;
 	int kind;
 
-	kind = sha1_object_info(sha1, NULL);
+	kind = sha1_object_info(oid->hash, NULL);
 	if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 		return 1;
 	if (kind != OBJ_TAG)
 		return 0;
 
 	/* We need to do this the hard way... */
-	obj = deref_tag(parse_object(sha1), NULL, 0);
+	obj = deref_tag(parse_object(oid->hash), NULL, 0);
 	if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 		return 1;
 	return 0;
 }
 
-static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unused)
+static int disambiguate_blob_only(const struct object_id *oid, void *cb_data_unused)
 {
-	int kind = sha1_object_info(sha1, NULL);
+	int kind = sha1_object_info(oid->hash, NULL);
 	return kind == OBJ_BLOB;
 }
 
@@ -332,7 +333,7 @@
 		ds->hex_pfx[i] = c;
 		if (!(i & 1))
 			val <<= 4;
-		ds->bin_pfx[i >> 1] |= val;
+		ds->bin_pfx.hash[i >> 1] |= val;
 	}
 
 	ds->len = len;
@@ -341,31 +342,32 @@
 	return 0;
 }
 
-static int show_ambiguous_object(const unsigned char *sha1, void *data)
+static int show_ambiguous_object(const struct object_id *oid, void *data)
 {
 	const struct disambiguate_state *ds = data;
 	struct strbuf desc = STRBUF_INIT;
 	int type;
 
-	if (ds->fn && !ds->fn(sha1, ds->cb_data))
+
+	if (ds->fn && !ds->fn(oid, ds->cb_data))
 		return 0;
 
-	type = sha1_object_info(sha1, NULL);
+	type = sha1_object_info(oid->hash, NULL);
 	if (type == OBJ_COMMIT) {
-		struct commit *commit = lookup_commit(sha1);
+		struct commit *commit = lookup_commit(oid->hash);
 		if (commit) {
 			struct pretty_print_context pp = {0};
 			pp.date_mode.type = DATE_SHORT;
 			format_commit_message(commit, " %ad - %s", &desc, &pp);
 		}
 	} else if (type == OBJ_TAG) {
-		struct tag *tag = lookup_tag(sha1);
+		struct tag *tag = lookup_tag(oid->hash);
 		if (!parse_tag(tag) && tag->tag)
 			strbuf_addf(&desc, " %s", tag->tag);
 	}
 
 	advise("  %s %s%s",
-	       find_unique_abbrev(sha1, DEFAULT_ABBREV),
+	       find_unique_abbrev(oid->hash, DEFAULT_ABBREV),
 	       typename(type) ? typename(type) : "unknown type",
 	       desc.buf);
 
@@ -422,15 +424,15 @@
 	return status;
 }
 
-static int collect_ambiguous(const unsigned char *sha1, void *data)
+static int collect_ambiguous(const struct object_id *oid, void *data)
 {
-	sha1_array_append(data, sha1);
+	oid_array_append(data, oid);
 	return 0;
 }
 
 int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 {
-	struct sha1_array collect = SHA1_ARRAY_INIT;
+	struct oid_array collect = OID_ARRAY_INIT;
 	struct disambiguate_state ds;
 	int ret;
 
@@ -443,8 +445,8 @@
 	find_short_object_filename(&ds);
 	find_short_packed_object(&ds);
 
-	ret = sha1_array_for_each_unique(&collect, fn, cb_data);
-	sha1_array_clear(&collect);
+	ret = oid_array_for_each_unique(&collect, fn, cb_data);
+	oid_array_clear(&collect);
 	return ret;
 }
 
@@ -509,7 +511,7 @@
 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 {
 	static int bufno;
-	static char hexbuffer[4][GIT_SHA1_HEXSZ + 1];
+	static char hexbuffer[4][GIT_MAX_HEXSZ + 1];
 	char *hex = hexbuffer[bufno];
 	bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
 	find_unique_abbrev_r(hex, sha1, len);
@@ -549,7 +551,7 @@
 	for (i = 0; i < nr; i++) {
 		int suffix_len = strlen(suffix[i]);
 		if (suffix_len <= len
-		    && !memcmp(string, suffix[i], suffix_len))
+		    && !strncasecmp(string, suffix[i], suffix_len))
 			return suffix_len;
 	}
 	return 0;
diff --git a/shallow.c b/shallow.c
index 11f7dde..25b6db9 100644
--- a/shallow.c
+++ b/shallow.c
@@ -260,7 +260,7 @@
 }
 
 static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol,
-				   const struct sha1_array *extra,
+				   const struct oid_array *extra,
 				   unsigned flags)
 {
 	struct write_shallow_data data;
@@ -273,7 +273,7 @@
 	if (!extra)
 		return data.count;
 	for (i = 0; i < extra->nr; i++) {
-		strbuf_addstr(out, sha1_to_hex(extra->sha1[i]));
+		strbuf_addstr(out, oid_to_hex(extra->oid + i));
 		strbuf_addch(out, '\n');
 		data.count++;
 	}
@@ -281,14 +281,14 @@
 }
 
 int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
-			  const struct sha1_array *extra)
+			  const struct oid_array *extra)
 {
 	return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
 }
 
 static struct tempfile temporary_shallow;
 
-const char *setup_temporary_shallow(const struct sha1_array *extra)
+const char *setup_temporary_shallow(const struct oid_array *extra)
 {
 	struct strbuf sb = STRBUF_INIT;
 	int fd;
@@ -312,7 +312,7 @@
 
 void setup_alternate_shallow(struct lock_file *shallow_lock,
 			     const char **alternate_shallow_file,
-			     const struct sha1_array *extra)
+			     const struct oid_array *extra)
 {
 	struct strbuf sb = STRBUF_INIT;
 	int fd;
@@ -385,7 +385,7 @@
  * Step 1, split sender shallow commits into "ours" and "theirs"
  * Step 2, clean "ours" based on .git/shallow
  */
-void prepare_shallow_info(struct shallow_info *info, struct sha1_array *sa)
+void prepare_shallow_info(struct shallow_info *info, struct oid_array *sa)
 {
 	int i;
 	trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n");
@@ -396,9 +396,9 @@
 	ALLOC_ARRAY(info->ours, sa->nr);
 	ALLOC_ARRAY(info->theirs, sa->nr);
 	for (i = 0; i < sa->nr; i++) {
-		if (has_sha1_file(sa->sha1[i])) {
+		if (has_object_file(sa->oid + i)) {
 			struct commit_graft *graft;
-			graft = lookup_commit_graft(sa->sha1[i]);
+			graft = lookup_commit_graft(sa->oid[i].hash);
 			if (graft && graft->nr_parent < 0)
 				continue;
 			info->ours[info->nr_ours++] = i;
@@ -417,13 +417,13 @@
 
 void remove_nonexistent_theirs_shallow(struct shallow_info *info)
 {
-	unsigned char (*sha1)[20] = info->shallow->sha1;
+	struct object_id *oid = info->shallow->oid;
 	int i, dst;
 	trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n");
 	for (i = dst = 0; i < info->nr_theirs; i++) {
 		if (i != dst)
 			info->theirs[dst] = info->theirs[i];
-		if (has_sha1_file(sha1[info->theirs[i]]))
+		if (has_object_file(oid + info->theirs[i]))
 			dst++;
 	}
 	info->nr_theirs = dst;
@@ -559,8 +559,8 @@
 void assign_shallow_commits_to_refs(struct shallow_info *info,
 				    uint32_t **used, int *ref_status)
 {
-	unsigned char (*sha1)[20] = info->shallow->sha1;
-	struct sha1_array *ref = info->ref;
+	struct object_id *oid = info->shallow->oid;
+	struct oid_array *ref = info->ref;
 	unsigned int i, nr;
 	int *shallow, nr_shallow = 0;
 	struct paint_info pi;
@@ -599,18 +599,18 @@
 
 	/* Mark potential bottoms so we won't go out of bound */
 	for (i = 0; i < nr_shallow; i++) {
-		struct commit *c = lookup_commit(sha1[shallow[i]]);
+		struct commit *c = lookup_commit(oid[shallow[i]].hash);
 		c->object.flags |= BOTTOM;
 	}
 
 	for (i = 0; i < ref->nr; i++)
-		paint_down(&pi, ref->sha1[i], i);
+		paint_down(&pi, ref->oid[i].hash, i);
 
 	if (used) {
 		int bitmap_size = ((pi.nr_bits + 31) / 32) * sizeof(uint32_t);
 		memset(used, 0, sizeof(*used) * info->shallow->nr);
 		for (i = 0; i < nr_shallow; i++) {
-			const struct commit *c = lookup_commit(sha1[shallow[i]]);
+			const struct commit *c = lookup_commit(oid[shallow[i]].hash);
 			uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
 			if (*map)
 				used[shallow[i]] = xmemdupz(*map, bitmap_size);
@@ -664,7 +664,7 @@
 				struct ref_bitmap *ref_bitmap,
 				int *ref_status)
 {
-	unsigned char (*sha1)[20] = info->shallow->sha1;
+	struct object_id *oid = info->shallow->oid;
 	struct commit *c;
 	uint32_t **bitmap;
 	int dst, i, j;
@@ -679,7 +679,7 @@
 	for (i = dst = 0; i < info->nr_theirs; i++) {
 		if (i != dst)
 			info->theirs[dst] = info->theirs[i];
-		c = lookup_commit(sha1[info->theirs[i]]);
+		c = lookup_commit(oid[info->theirs[i]].hash);
 		bitmap = ref_bitmap_at(ref_bitmap, c);
 		if (!*bitmap)
 			continue;
@@ -700,7 +700,7 @@
 	for (i = dst = 0; i < info->nr_ours; i++) {
 		if (i != dst)
 			info->ours[dst] = info->ours[i];
-		c = lookup_commit(sha1[info->ours[i]]);
+		c = lookup_commit(oid[info->ours[i]].hash);
 		bitmap = ref_bitmap_at(ref_bitmap, c);
 		if (!*bitmap)
 			continue;
@@ -722,7 +722,7 @@
 int delayed_reachability_test(struct shallow_info *si, int c)
 {
 	if (si->need_reachability_test[c]) {
-		struct commit *commit = lookup_commit(si->shallow->sha1[c]);
+		struct commit *commit = lookup_commit(si->shallow->oid[c].hash);
 
 		if (!si->commits) {
 			struct commit_array ca;
diff --git a/strbuf.c b/strbuf.c
index ace58e7..0045794 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -449,6 +449,17 @@
 			strbuf_setlen(sb, strlen(sb->buf));
 			return 0;
 		}
+
+		/*
+		 * If getcwd(3) is implemented as a syscall that falls
+		 * back to a regular lookup using readdir(3) etc. then
+		 * we may be able to avoid EACCES by providing enough
+		 * space to the syscall as it's not necessarily bound
+		 * to the same restrictions as the fallback.
+		 */
+		if (errno == EACCES && guessed_len < PATH_MAX)
+			continue;
+
 		if (errno != ERANGE)
 			break;
 	}
diff --git a/string-list.c b/string-list.c
index 45016ad..003ca18 100644
--- a/string-list.c
+++ b/string-list.c
@@ -41,10 +41,7 @@
 	if (exact_match)
 		return -1 - index;
 
-	if (list->nr + 1 >= list->alloc) {
-		list->alloc += 32;
-		REALLOC_ARRAY(list->items, list->alloc);
-	}
+	ALLOC_GROW(list->items, list->nr+1, list->alloc);
 	if (index < list->nr)
 		memmove(list->items + index + 1, list->items + index,
 				(list->nr - index)
diff --git a/submodule.c b/submodule.c
index 040f4c2..d3299e2 100644
--- a/submodule.c
+++ b/submodule.c
@@ -14,6 +14,7 @@
 #include "blob.h"
 #include "thread-utils.h"
 #include "quote.h"
+#include "remote.h"
 #include "worktree.h"
 
 static int config_fetch_recurse_submodules = RECURSE_SUBMODULES_ON_DEMAND;
@@ -21,8 +22,8 @@
 static int parallel_jobs = 1;
 static struct string_list changed_submodule_paths = STRING_LIST_INIT_NODUP;
 static int initialized_fetch_ref_tips;
-static struct sha1_array ref_tips_before_fetch;
-static struct sha1_array ref_tips_after_fetch;
+static struct oid_array ref_tips_before_fetch;
+static struct oid_array ref_tips_after_fetch;
 
 /*
  * The following flag is set if the .gitmodules file is unmerged. We then
@@ -213,25 +214,59 @@
 }
 
 /*
+ * NEEDSWORK: With the addition of different configuration options to determine
+ * if a submodule is of interests, the validity of this function's name comes
+ * into question.  Once the dust has settled and more concrete terminology is
+ * decided upon, come up with a more proper name for this function.  One
+ * potential candidate could be 'is_submodule_active()'.
+ *
  * Determine if a submodule has been initialized at a given 'path'
  */
 int is_submodule_initialized(const char *path)
 {
 	int ret = 0;
-	const struct submodule *module = NULL;
+	char *key = NULL;
+	char *value = NULL;
+	const struct string_list *sl;
+	const struct submodule *module = submodule_from_path(null_sha1, path);
 
-	module = submodule_from_path(null_sha1, path);
+	/* early return if there isn't a path->module mapping */
+	if (!module)
+		return 0;
 
-	if (module) {
-		char *key = xstrfmt("submodule.%s.url", module->name);
-		char *value = NULL;
-
-		ret = !git_config_get_string(key, &value);
-
-		free(value);
+	/* submodule.<name>.active is set */
+	key = xstrfmt("submodule.%s.active", module->name);
+	if (!git_config_get_bool(key, &ret)) {
 		free(key);
+		return ret;
+	}
+	free(key);
+
+	/* submodule.active is set */
+	sl = git_config_get_value_multi("submodule.active");
+	if (sl) {
+		struct pathspec ps;
+		struct argv_array args = ARGV_ARRAY_INIT;
+		const struct string_list_item *item;
+
+		for_each_string_list_item(item, sl) {
+			argv_array_push(&args, item->string);
+		}
+
+		parse_pathspec(&ps, 0, 0, NULL, args.argv);
+		ret = match_pathspec(&ps, path, strlen(path), 0, NULL, 1);
+
+		argv_array_clear(&args);
+		clear_pathspec(&ps);
+		return ret;
 	}
 
+	/* fallback to checking if the URL is set */
+	key = xstrfmt("submodule.%s.url", module->name);
+	ret = !git_config_get_string(key, &value);
+
+	free(value);
+	free(key);
 	return ret;
 }
 
@@ -542,6 +577,7 @@
 	if (!(dirty_submodule & DIRTY_SUBMODULE_MODIFIED))
 		argv_array_push(&cp.args, oid_to_hex(new));
 
+	prepare_submodule_repo_env(&cp.env_array);
 	if (run_command(&cp))
 		fprintf(f, "(diff failed)\n");
 
@@ -587,35 +623,35 @@
 	return 1;
 }
 
-static int append_sha1_to_argv(const unsigned char sha1[20], void *data)
+static int append_oid_to_argv(const struct object_id *oid, void *data)
 {
 	struct argv_array *argv = data;
-	argv_array_push(argv, sha1_to_hex(sha1));
+	argv_array_push(argv, oid_to_hex(oid));
 	return 0;
 }
 
-static int check_has_commit(const unsigned char sha1[20], void *data)
+static int check_has_commit(const struct object_id *oid, void *data)
 {
 	int *has_commit = data;
 
-	if (!lookup_commit_reference(sha1))
+	if (!lookup_commit_reference(oid->hash))
 		*has_commit = 0;
 
 	return 0;
 }
 
-static int submodule_has_commits(const char *path, struct sha1_array *commits)
+static int submodule_has_commits(const char *path, struct oid_array *commits)
 {
 	int has_commit = 1;
 
 	if (add_submodule_odb(path))
 		return 0;
 
-	sha1_array_for_each_unique(commits, check_has_commit, &has_commit);
+	oid_array_for_each_unique(commits, check_has_commit, &has_commit);
 	return has_commit;
 }
 
-static int submodule_needs_pushing(const char *path, struct sha1_array *commits)
+static int submodule_needs_pushing(const char *path, struct oid_array *commits)
 {
 	if (!submodule_has_commits(path, commits))
 		/*
@@ -637,7 +673,7 @@
 		int needs_pushing = 0;
 
 		argv_array_push(&cp.args, "rev-list");
-		sha1_array_for_each_unique(commits, append_sha1_to_argv, &cp.args);
+		oid_array_for_each_unique(commits, append_oid_to_argv, &cp.args);
 		argv_array_pushl(&cp.args, "--not", "--remotes", "-n", "1" , NULL);
 
 		prepare_submodule_repo_env(&cp.env_array);
@@ -659,18 +695,18 @@
 	return 0;
 }
 
-static struct sha1_array *submodule_commits(struct string_list *submodules,
+static struct oid_array *submodule_commits(struct string_list *submodules,
 					    const char *path)
 {
 	struct string_list_item *item;
 
 	item = string_list_insert(submodules, path);
 	if (item->util)
-		return (struct sha1_array *) item->util;
+		return (struct oid_array *) item->util;
 
-	/* NEEDSWORK: should we have sha1_array_init()? */
-	item->util = xcalloc(1, sizeof(struct sha1_array));
-	return (struct sha1_array *) item->util;
+	/* NEEDSWORK: should we have oid_array_init()? */
+	item->util = xcalloc(1, sizeof(struct oid_array));
+	return (struct oid_array *) item->util;
 }
 
 static void collect_submodules_from_diff(struct diff_queue_struct *q,
@@ -682,11 +718,11 @@
 
 	for (i = 0; i < q->nr; i++) {
 		struct diff_filepair *p = q->queue[i];
-		struct sha1_array *commits;
+		struct oid_array *commits;
 		if (!S_ISGITLINK(p->two->mode))
 			continue;
 		commits = submodule_commits(submodules, p->two->path);
-		sha1_array_append(commits, p->two->oid.hash);
+		oid_array_append(commits, &p->two->oid);
 	}
 }
 
@@ -706,11 +742,11 @@
 {
 	struct string_list_item *item;
 	for_each_string_list_item(item, submodules)
-		sha1_array_clear((struct sha1_array *) item->util);
+		oid_array_clear((struct oid_array *) item->util);
 	string_list_clear(submodules, 1);
 }
 
-int find_unpushed_submodules(struct sha1_array *commits,
+int find_unpushed_submodules(struct oid_array *commits,
 		const char *remotes_name, struct string_list *needs_pushing)
 {
 	struct rev_info rev;
@@ -723,7 +759,7 @@
 
 	/* argv.argv[0] will be ignored by setup_revisions */
 	argv_array_push(&argv, "find_unpushed_submodules");
-	sha1_array_for_each_unique(commits, append_sha1_to_argv, &argv);
+	oid_array_for_each_unique(commits, append_oid_to_argv, &argv);
 	argv_array_push(&argv, "--not");
 	argv_array_pushf(&argv, "--remotes=%s", remotes_name);
 
@@ -738,7 +774,7 @@
 	argv_array_clear(&argv);
 
 	for_each_string_list_item(submodule, &submodules) {
-		struct sha1_array *commits = (struct sha1_array *) submodule->util;
+		struct oid_array *commits = (struct oid_array *) submodule->util;
 
 		if (submodule_needs_pushing(submodule->string, commits))
 			string_list_insert(needs_pushing, submodule->string);
@@ -748,7 +784,11 @@
 	return needs_pushing->nr;
 }
 
-static int push_submodule(const char *path, int dry_run)
+static int push_submodule(const char *path,
+			  const struct remote *remote,
+			  const char **refspec, int refspec_nr,
+			  const struct string_list *push_options,
+			  int dry_run)
 {
 	if (add_submodule_odb(path))
 		return 1;
@@ -759,6 +799,20 @@
 		if (dry_run)
 			argv_array_push(&cp.args, "--dry-run");
 
+		if (push_options && push_options->nr) {
+			const struct string_list_item *item;
+			for_each_string_list_item(item, push_options)
+				argv_array_pushf(&cp.args, "--push-option=%s",
+						 item->string);
+		}
+
+		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]);
+		}
+
 		prepare_submodule_repo_env(&cp.env_array);
 		cp.git_cmd = 1;
 		cp.no_stdin = 1;
@@ -771,20 +825,67 @@
 	return 1;
 }
 
-int push_unpushed_submodules(struct sha1_array *commits,
-			     const char *remotes_name,
+/*
+ * Perform a check in the submodule to see if the remote and refspec work.
+ * Die if the submodule can't be pushed.
+ */
+static void submodule_push_check(const char *path, const struct remote *remote,
+				 const char **refspec, int refspec_nr)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+	int i;
+
+	argv_array_push(&cp.args, "submodule--helper");
+	argv_array_push(&cp.args, "push-check");
+	argv_array_push(&cp.args, remote->name);
+
+	for (i = 0; i < refspec_nr; i++)
+		argv_array_push(&cp.args, refspec[i]);
+
+	prepare_submodule_repo_env(&cp.env_array);
+	cp.git_cmd = 1;
+	cp.no_stdin = 1;
+	cp.no_stdout = 1;
+	cp.dir = path;
+
+	/*
+	 * Simply indicate if 'submodule--helper push-check' failed.
+	 * More detailed error information will be provided by the
+	 * child process.
+	 */
+	if (run_command(&cp))
+		die("process for submodule '%s' failed", path);
+}
+
+int push_unpushed_submodules(struct oid_array *commits,
+			     const struct remote *remote,
+			     const char **refspec, int refspec_nr,
+			     const struct string_list *push_options,
 			     int dry_run)
 {
 	int i, ret = 1;
 	struct string_list needs_pushing = STRING_LIST_INIT_DUP;
 
-	if (!find_unpushed_submodules(commits, remotes_name, &needs_pushing))
+	if (!find_unpushed_submodules(commits, remote->name, &needs_pushing))
 		return 1;
 
+	/*
+	 * Verify that the remote and refspec can be propagated to all
+	 * submodules.  This check can be skipped if the remote and refspec
+	 * won't be propagated due to the remote being unconfigured (e.g. a URL
+	 * instead of a remote name).
+	 */
+	if (remote->origin != REMOTE_UNCONFIGURED)
+		for (i = 0; i < needs_pushing.nr; i++)
+			submodule_push_check(needs_pushing.items[i].string,
+					     remote, refspec, refspec_nr);
+
+	/* Actually push the submodules */
 	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, dry_run)) {
+		if (!push_submodule(path, remote, refspec, refspec_nr,
+				    push_options, dry_run)) {
 			fprintf(stderr, "Unable to push submodule '%s'\n", path);
 			ret = 0;
 		}
@@ -853,23 +954,23 @@
 static int add_sha1_to_array(const char *ref, const struct object_id *oid,
 			     int flags, void *data)
 {
-	sha1_array_append(data, oid->hash);
+	oid_array_append(data, oid);
 	return 0;
 }
 
-void check_for_new_submodule_commits(unsigned char new_sha1[20])
+void check_for_new_submodule_commits(struct object_id *oid)
 {
 	if (!initialized_fetch_ref_tips) {
 		for_each_ref(add_sha1_to_array, &ref_tips_before_fetch);
 		initialized_fetch_ref_tips = 1;
 	}
 
-	sha1_array_append(&ref_tips_after_fetch, new_sha1);
+	oid_array_append(&ref_tips_after_fetch, oid);
 }
 
-static int add_sha1_to_argv(const unsigned char sha1[20], void *data)
+static int add_oid_to_argv(const struct object_id *oid, void *data)
 {
-	argv_array_push(data, sha1_to_hex(sha1));
+	argv_array_push(data, oid_to_hex(oid));
 	return 0;
 }
 
@@ -885,11 +986,11 @@
 
 	init_revisions(&rev, NULL);
 	argv_array_push(&argv, "--"); /* argv[0] program name */
-	sha1_array_for_each_unique(&ref_tips_after_fetch,
-				   add_sha1_to_argv, &argv);
+	oid_array_for_each_unique(&ref_tips_after_fetch,
+				   add_oid_to_argv, &argv);
 	argv_array_push(&argv, "--not");
-	sha1_array_for_each_unique(&ref_tips_before_fetch,
-				   add_sha1_to_argv, &argv);
+	oid_array_for_each_unique(&ref_tips_before_fetch,
+				   add_oid_to_argv, &argv);
 	setup_revisions(argv.argc, argv.argv, &rev, NULL);
 	if (prepare_revision_walk(&rev))
 		die("revision walk setup failed");
@@ -915,8 +1016,8 @@
 	}
 
 	argv_array_clear(&argv);
-	sha1_array_clear(&ref_tips_before_fetch);
-	sha1_array_clear(&ref_tips_after_fetch);
+	oid_array_clear(&ref_tips_before_fetch);
+	oid_array_clear(&ref_tips_after_fetch);
 	initialized_fetch_ref_tips = 0;
 }
 
@@ -1077,67 +1178,78 @@
 
 unsigned is_submodule_modified(const char *path, int ignore_untracked)
 {
-	ssize_t len;
 	struct child_process cp = CHILD_PROCESS_INIT;
-	const char *argv[] = {
-		"status",
-		"--porcelain",
-		NULL,
-		NULL,
-	};
 	struct strbuf buf = STRBUF_INIT;
+	FILE *fp;
 	unsigned dirty_submodule = 0;
-	const char *line, *next_line;
 	const char *git_dir;
+	int ignore_cp_exit_code = 0;
 
 	strbuf_addf(&buf, "%s/.git", path);
 	git_dir = read_gitfile(buf.buf);
 	if (!git_dir)
 		git_dir = buf.buf;
-	if (!is_directory(git_dir)) {
+	if (!is_git_directory(git_dir)) {
+		if (is_directory(git_dir))
+			die(_("'%s' not recognized as a git repository"), git_dir);
 		strbuf_release(&buf);
 		/* The submodule is not checked out, so it is not modified */
 		return 0;
-
 	}
 	strbuf_reset(&buf);
 
+	argv_array_pushl(&cp.args, "status", "--porcelain=2", NULL);
 	if (ignore_untracked)
-		argv[2] = "-uno";
+		argv_array_push(&cp.args, "-uno");
 
-	cp.argv = argv;
 	prepare_submodule_repo_env(&cp.env_array);
 	cp.git_cmd = 1;
 	cp.no_stdin = 1;
 	cp.out = -1;
 	cp.dir = path;
 	if (start_command(&cp))
-		die("Could not run 'git status --porcelain' in submodule %s", path);
+		die("Could not run 'git status --porcelain=2' in submodule %s", path);
 
-	len = strbuf_read(&buf, cp.out, 1024);
-	line = buf.buf;
-	while (len > 2) {
-		if ((line[0] == '?') && (line[1] == '?')) {
+	fp = xfdopen(cp.out, "r");
+	while (strbuf_getwholeline(&buf, fp, '\n') != EOF) {
+		/* regular untracked files */
+		if (buf.buf[0] == '?')
 			dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
-			if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
-				break;
-		} else {
-			dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
-			if (ignore_untracked ||
-			    (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED))
-				break;
-		}
-		next_line = strchr(line, '\n');
-		if (!next_line)
-			break;
-		next_line++;
-		len -= (next_line - line);
-		line = next_line;
-	}
-	close(cp.out);
 
-	if (finish_command(&cp))
-		die("'git status --porcelain' failed in submodule %s", path);
+		if (buf.buf[0] == 'u' ||
+		    buf.buf[0] == '1' ||
+		    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",
+				    buf.buf);
+
+			if (buf.buf[5] == 'S' && buf.buf[8] == 'U')
+				/* nested untracked file */
+				dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
+
+			if (buf.buf[0] == 'u' ||
+			    buf.buf[0] == '2' ||
+			    memcmp(buf.buf + 5, "S..U", 4))
+				/* other change */
+				dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
+		}
+
+		if ((dirty_submodule & DIRTY_SUBMODULE_MODIFIED) &&
+		    ((dirty_submodule & DIRTY_SUBMODULE_UNTRACKED) ||
+		     ignore_untracked)) {
+			/*
+			 * We're not interested in any further information from
+			 * the child any more, neither output nor its exit code.
+			 */
+			ignore_cp_exit_code = 1;
+			break;
+		}
+	}
+	fclose(fp);
+
+	if (finish_command(&cp) && !ignore_cp_exit_code)
+		die("'git status --porcelain=2' failed in submodule %s", path);
 
 	strbuf_release(&buf);
 	return dirty_submodule;
@@ -1217,7 +1329,7 @@
 	cp.dir = path;
 	if (start_command(&cp)) {
 		if (flags & SUBMODULE_REMOVAL_DIE_ON_ERROR)
-			die(_("could not start 'git status in submodule '%s'"),
+			die(_("could not start 'git status' in submodule '%s'"),
 				path);
 		ret = -1;
 		goto out;
@@ -1230,7 +1342,7 @@
 
 	if (finish_command(&cp)) {
 		if (flags & SUBMODULE_REMOVAL_DIE_ON_ERROR)
-			die(_("could not run 'git status in submodule '%s'"),
+			die(_("could not run 'git status' in submodule '%s'"),
 				path);
 		ret = -1;
 	}
@@ -1362,8 +1474,7 @@
 			cp1.no_stdin = 1;
 			cp1.dir = path;
 
-			argv_array_pushl(&cp1.args, "update-ref", "HEAD",
-					 new ? new : EMPTY_TREE_SHA1_HEX, NULL);
+			argv_array_pushl(&cp1.args, "update-ref", "HEAD", new, NULL);
 
 			if (run_command(&cp1)) {
 				ret = -1;
@@ -1402,7 +1513,7 @@
 	memset(&rev_opts, 0, sizeof(rev_opts));
 
 	/* get all revisions that merge commit a */
-	snprintf(merged_revision, sizeof(merged_revision), "^%s",
+	xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
 			oid_to_hex(&a->object.oid));
 	init_revisions(&revs, NULL);
 	rev_opts.submodule = path;
@@ -1754,3 +1865,34 @@
 
 	return ret;
 }
+
+int submodule_to_gitdir(struct strbuf *buf, const char *submodule)
+{
+	const struct submodule *sub;
+	const char *git_dir;
+	int ret = 0;
+
+	strbuf_reset(buf);
+	strbuf_addstr(buf, submodule);
+	strbuf_complete(buf, '/');
+	strbuf_addstr(buf, ".git");
+
+	git_dir = read_gitfile(buf->buf);
+	if (git_dir) {
+		strbuf_reset(buf);
+		strbuf_addstr(buf, git_dir);
+	}
+	if (!is_git_directory(buf->buf)) {
+		gitmodules_config();
+		sub = submodule_from_path(null_sha1, submodule);
+		if (!sub) {
+			ret = -1;
+			goto cleanup;
+		}
+		strbuf_reset(buf);
+		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
+	}
+
+cleanup:
+	return ret;
+}
diff --git a/submodule.h b/submodule.h
index 8a8bc49..1277480 100644
--- a/submodule.h
+++ b/submodule.h
@@ -3,7 +3,8 @@
 
 struct diff_options;
 struct argv_array;
-struct sha1_array;
+struct oid_array;
+struct remote;
 
 enum {
 	RECURSE_SUBMODULES_ONLY = -5,
@@ -72,7 +73,7 @@
  * and it should be updated. Returns NULL otherwise.
  */
 extern const struct submodule *submodule_from_ce(const struct cache_entry *ce);
-extern void check_for_new_submodule_commits(unsigned char new_sha1[20]);
+extern void check_for_new_submodule_commits(struct object_id *oid);
 extern int fetch_populated_submodules(const struct argv_array *options,
 			       const char *prefix, int command_line_option,
 			       int quiet, int max_parallel_jobs);
@@ -87,14 +88,22 @@
 			   const unsigned char base[20],
 			   const unsigned char a[20],
 			   const unsigned char b[20], int search);
-extern int find_unpushed_submodules(struct sha1_array *commits,
+extern int find_unpushed_submodules(struct oid_array *commits,
 				    const char *remotes_name,
 				    struct string_list *needs_pushing);
-extern int push_unpushed_submodules(struct sha1_array *commits,
-				    const char *remotes_name,
+extern int push_unpushed_submodules(struct oid_array *commits,
+				    const struct remote *remote,
+				    const char **refspec, int refspec_nr,
+				    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);
 extern int parallel_submodules(void);
+/*
+ * Given a submodule path (as in the index), return the repository
+ * path of that submodule in 'buf'. Return -1 on error or when the
+ * submodule is not initialized.
+ */
+int submodule_to_gitdir(struct strbuf *buf, const char *submodule);
 
 #define SUBMODULE_MOVE_HEAD_DRY_RUN (1<<0)
 #define SUBMODULE_MOVE_HEAD_FORCE   (1<<1)
diff --git a/t/README b/t/README
index 4982d1c..ab386c3 100644
--- a/t/README
+++ b/t/README
@@ -471,13 +471,13 @@
    their output.
 
    You can glean some further possible issues from the TAP grammar
-   (see http://search.cpan.org/perldoc?TAP::Parser::Grammar#TAP_Grammar)
+   (see https://metacpan.org/pod/TAP::Parser::Grammar#TAP-GRAMMAR)
    but the best indication is to just run the tests with prove(1),
    it'll complain if anything is amiss.
 
 Keep in mind:
 
- - Inside <script> part, the standard output and standard error
+ - Inside the <script> part, the standard output and standard error
    streams are discarded, and the test harness only reports "ok" or
    "not ok" to the end user running the tests. Under --verbose, they
    are shown to help debugging the tests.
@@ -611,9 +611,11 @@
 
  - test_have_prereq <prereq>
 
-   Check if we have a prerequisite previously set with
-   test_set_prereq. The most common use of this directly is to skip
-   all the tests if we don't have some essential prerequisite:
+   Check if we have a prerequisite previously set with test_set_prereq.
+   The most common way to use this explicitly (as opposed to the
+   implicit use when an argument is passed to test_expect_*) is to skip
+   all the tests at the start of the test script if we don't have some
+   essential prerequisite:
 
 	if ! test_have_prereq PERL
 	then
diff --git a/t/helper/.gitignore b/t/helper/.gitignore
index 758ed2e..7216502 100644
--- a/t/helper/.gitignore
+++ b/t/helper/.gitignore
@@ -16,16 +16,19 @@
 /test-match-trees
 /test-mergesort
 /test-mktemp
+/test-online-cpus
 /test-parse-options
 /test-path-utils
 /test-prio-queue
 /test-read-cache
+/test-ref-store
 /test-regex
 /test-revision-walking
 /test-run-command
 /test-sha1
 /test-sha1-array
 /test-sigchain
+/test-strcmp-offset
 /test-string-list
 /test-submodule-config
 /test-subprocess
diff --git a/t/helper/test-online-cpus.c b/t/helper/test-online-cpus.c
new file mode 100644
index 0000000..06c09c6
--- /dev/null
+++ b/t/helper/test-online-cpus.c
@@ -0,0 +1,8 @@
+#include "git-compat-util.h"
+#include "thread-utils.h"
+
+int cmd_main(int argc, const char **argv)
+{
+	printf("%d\n", online_cpus());
+	return 0;
+}
diff --git a/t/helper/test-read-cache.c b/t/helper/test-read-cache.c
index 2a7990e..48255ee 100644
--- a/t/helper/test-read-cache.c
+++ b/t/helper/test-read-cache.c
@@ -5,6 +5,7 @@
 	int i, cnt = 1;
 	if (argc == 2)
 		cnt = strtol(argv[1], NULL, 0);
+	setup_git_directory();
 	for (i = 0; i < cnt; i++) {
 		read_cache();
 		discard_cache();
diff --git a/t/helper/test-ref-store.c b/t/helper/test-ref-store.c
new file mode 100644
index 0000000..2d84c45
--- /dev/null
+++ b/t/helper/test-ref-store.c
@@ -0,0 +1,277 @@
+#include "cache.h"
+#include "refs.h"
+
+static const char *notnull(const char *arg, const char *name)
+{
+	if (!arg)
+		die("%s required", name);
+	return arg;
+}
+
+static unsigned int arg_flags(const char *arg, const char *name)
+{
+	return atoi(notnull(arg, name));
+}
+
+static const char **get_store(const char **argv, struct ref_store **refs)
+{
+	const char *gitdir;
+
+	if (!argv[0]) {
+		die("ref store required");
+	} else if (!strcmp(argv[0], "main")) {
+		*refs = get_main_ref_store();
+	} else if (skip_prefix(argv[0], "submodule:", &gitdir)) {
+		struct strbuf sb = STRBUF_INIT;
+		int ret;
+
+		ret = strbuf_git_path_submodule(&sb, gitdir, "objects/");
+		if (ret)
+			die("strbuf_git_path_submodule failed: %d", ret);
+		add_to_alternates_memory(sb.buf);
+		strbuf_release(&sb);
+
+		*refs = get_submodule_ref_store(gitdir);
+	} else
+		die("unknown backend %s", argv[0]);
+
+	if (!*refs)
+		die("no ref store");
+
+	/* consume store-specific optional arguments if needed */
+
+	return argv + 1;
+}
+
+
+static int cmd_pack_refs(struct ref_store *refs, const char **argv)
+{
+	unsigned int flags = arg_flags(*argv++, "flags");
+
+	return refs_pack_refs(refs, flags);
+}
+
+static int cmd_peel_ref(struct ref_store *refs, const char **argv)
+{
+	const char *refname = notnull(*argv++, "refname");
+	unsigned char sha1[20];
+	int ret;
+
+	ret = refs_peel_ref(refs, refname, sha1);
+	if (!ret)
+		puts(sha1_to_hex(sha1));
+	return ret;
+}
+
+static int cmd_create_symref(struct ref_store *refs, const char **argv)
+{
+	const char *refname = notnull(*argv++, "refname");
+	const char *target = notnull(*argv++, "target");
+	const char *logmsg = *argv++;
+
+	return refs_create_symref(refs, refname, target, logmsg);
+}
+
+static int cmd_delete_refs(struct ref_store *refs, const char **argv)
+{
+	unsigned int flags = arg_flags(*argv++, "flags");
+	struct string_list refnames = STRING_LIST_INIT_NODUP;
+
+	while (*argv)
+		string_list_append(&refnames, *argv++);
+
+	return refs_delete_refs(refs, &refnames, flags);
+}
+
+static int cmd_rename_ref(struct ref_store *refs, const char **argv)
+{
+	const char *oldref = notnull(*argv++, "oldref");
+	const char *newref = notnull(*argv++, "newref");
+	const char *logmsg = *argv++;
+
+	return refs_rename_ref(refs, oldref, newref, logmsg);
+}
+
+static int each_ref(const char *refname, const struct object_id *oid,
+		    int flags, void *cb_data)
+{
+	printf("%s %s 0x%x\n", oid_to_hex(oid), refname, flags);
+	return 0;
+}
+
+static int cmd_for_each_ref(struct ref_store *refs, const char **argv)
+{
+	const char *prefix = notnull(*argv++, "prefix");
+
+	return refs_for_each_ref_in(refs, prefix, each_ref, NULL);
+}
+
+static int cmd_resolve_ref(struct ref_store *refs, const char **argv)
+{
+	unsigned char sha1[20];
+	const char *refname = notnull(*argv++, "refname");
+	int resolve_flags = arg_flags(*argv++, "resolve-flags");
+	int flags;
+	const char *ref;
+
+	ref = refs_resolve_ref_unsafe(refs, refname, resolve_flags,
+				      sha1, &flags);
+	printf("%s %s 0x%x\n", sha1_to_hex(sha1), ref, flags);
+	return ref ? 0 : 1;
+}
+
+static int cmd_verify_ref(struct ref_store *refs, const char **argv)
+{
+	const char *refname = notnull(*argv++, "refname");
+	struct strbuf err = STRBUF_INIT;
+	int ret;
+
+	ret = refs_verify_refname_available(refs, refname, NULL, NULL, &err);
+	if (err.len)
+		puts(err.buf);
+	return ret;
+}
+
+static int cmd_for_each_reflog(struct ref_store *refs, const char **argv)
+{
+	return refs_for_each_reflog(refs, each_ref, NULL);
+}
+
+static int each_reflog(struct object_id *old_oid, struct object_id *new_oid,
+		       const char *committer, unsigned long timestamp,
+		       int tz, const char *msg, void *cb_data)
+{
+	printf("%s %s %s %lu %d %s\n",
+	       oid_to_hex(old_oid), oid_to_hex(new_oid),
+	       committer, timestamp, tz, msg);
+	return 0;
+}
+
+static int cmd_for_each_reflog_ent(struct ref_store *refs, const char **argv)
+{
+	const char *refname = notnull(*argv++, "refname");
+
+	return refs_for_each_reflog_ent(refs, refname, each_reflog, refs);
+}
+
+static int cmd_for_each_reflog_ent_reverse(struct ref_store *refs, const char **argv)
+{
+	const char *refname = notnull(*argv++, "refname");
+
+	return refs_for_each_reflog_ent_reverse(refs, refname, each_reflog, refs);
+}
+
+static int cmd_reflog_exists(struct ref_store *refs, const char **argv)
+{
+	const char *refname = notnull(*argv++, "refname");
+
+	return !refs_reflog_exists(refs, refname);
+}
+
+static int cmd_create_reflog(struct ref_store *refs, const char **argv)
+{
+	const char *refname = notnull(*argv++, "refname");
+	int force_create = arg_flags(*argv++, "force-create");
+	struct strbuf err = STRBUF_INIT;
+	int ret;
+
+	ret = refs_create_reflog(refs, refname, force_create, &err);
+	if (err.len)
+		puts(err.buf);
+	return ret;
+}
+
+static int cmd_delete_reflog(struct ref_store *refs, const char **argv)
+{
+	const char *refname = notnull(*argv++, "refname");
+
+	return refs_delete_reflog(refs, refname);
+}
+
+static int cmd_reflog_expire(struct ref_store *refs, const char **argv)
+{
+	die("not supported yet");
+}
+
+static int cmd_delete_ref(struct ref_store *refs, const char **argv)
+{
+	const char *msg = notnull(*argv++, "msg");
+	const char *refname = notnull(*argv++, "refname");
+	const char *sha1_buf = notnull(*argv++, "old-sha1");
+	unsigned int flags = arg_flags(*argv++, "flags");
+	unsigned char old_sha1[20];
+
+	if (get_sha1_hex(sha1_buf, old_sha1))
+		die("not sha-1");
+
+	return refs_delete_ref(refs, msg, refname, old_sha1, flags);
+}
+
+static int cmd_update_ref(struct ref_store *refs, const char **argv)
+{
+	const char *msg = notnull(*argv++, "msg");
+	const char *refname = notnull(*argv++, "refname");
+	const char *new_sha1_buf = notnull(*argv++, "old-sha1");
+	const char *old_sha1_buf = notnull(*argv++, "old-sha1");
+	unsigned int flags = arg_flags(*argv++, "flags");
+	unsigned char old_sha1[20];
+	unsigned char new_sha1[20];
+
+	if (get_sha1_hex(old_sha1_buf, old_sha1) ||
+	    get_sha1_hex(new_sha1_buf, new_sha1))
+		die("not sha-1");
+
+	return refs_update_ref(refs, msg, refname,
+			       new_sha1, old_sha1,
+			       flags, UPDATE_REFS_DIE_ON_ERR);
+}
+
+struct command {
+	const char *name;
+	int (*func)(struct ref_store *refs, const char **argv);
+};
+
+static struct command commands[] = {
+	{ "pack-refs", cmd_pack_refs },
+	{ "peel-ref", cmd_peel_ref },
+	{ "create-symref", cmd_create_symref },
+	{ "delete-refs", cmd_delete_refs },
+	{ "rename-ref", cmd_rename_ref },
+	{ "for-each-ref", cmd_for_each_ref },
+	{ "resolve-ref", cmd_resolve_ref },
+	{ "verify-ref", cmd_verify_ref },
+	{ "for-each-reflog", cmd_for_each_reflog },
+	{ "for-each-reflog-ent", cmd_for_each_reflog_ent },
+	{ "for-each-reflog-ent-reverse", cmd_for_each_reflog_ent_reverse },
+	{ "reflog-exists", cmd_reflog_exists },
+	{ "create-reflog", cmd_create_reflog },
+	{ "delete-reflog", cmd_delete_reflog },
+	{ "reflog-expire", cmd_reflog_expire },
+	/*
+	 * backend transaction functions can't be tested separately
+	 */
+	{ "delete-ref", cmd_delete_ref },
+	{ "update-ref", cmd_update_ref },
+	{ NULL, NULL }
+};
+
+int cmd_main(int argc, const char **argv)
+{
+	struct ref_store *refs;
+	const char *func;
+	struct command *cmd;
+
+	setup_git_directory();
+
+	argv = get_store(argv + 1, &refs);
+
+	func = *argv++;
+	if (!func)
+		die("ref function required");
+	for (cmd = commands; cmd->name; cmd++) {
+		if (!strcmp(func, cmd->name))
+			return cmd->func(refs, argv);
+	}
+	die("unknown function %s", func);
+	return 0;
+}
diff --git a/t/helper/test-sha1-array.c b/t/helper/test-sha1-array.c
index f7a53c4..edfd52d 100644
--- a/t/helper/test-sha1-array.c
+++ b/t/helper/test-sha1-array.c
@@ -1,33 +1,33 @@
 #include "cache.h"
 #include "sha1-array.h"
 
-static int print_sha1(const unsigned char sha1[20], void *data)
+static int print_oid(const struct object_id *oid, void *data)
 {
-	puts(sha1_to_hex(sha1));
+	puts(oid_to_hex(oid));
 	return 0;
 }
 
 int cmd_main(int argc, const char **argv)
 {
-	struct sha1_array array = SHA1_ARRAY_INIT;
+	struct oid_array array = OID_ARRAY_INIT;
 	struct strbuf line = STRBUF_INIT;
 
 	while (strbuf_getline(&line, stdin) != EOF) {
 		const char *arg;
-		unsigned char sha1[20];
+		struct object_id oid;
 
 		if (skip_prefix(line.buf, "append ", &arg)) {
-			if (get_sha1_hex(arg, sha1))
+			if (get_oid_hex(arg, &oid))
 				die("not a hexadecimal SHA1: %s", arg);
-			sha1_array_append(&array, sha1);
+			oid_array_append(&array, &oid);
 		} else if (skip_prefix(line.buf, "lookup ", &arg)) {
-			if (get_sha1_hex(arg, sha1))
+			if (get_oid_hex(arg, &oid))
 				die("not a hexadecimal SHA1: %s", arg);
-			printf("%d\n", sha1_array_lookup(&array, sha1));
+			printf("%d\n", oid_array_lookup(&array, &oid));
 		} else if (!strcmp(line.buf, "clear"))
-			sha1_array_clear(&array);
+			oid_array_clear(&array);
 		else if (!strcmp(line.buf, "for_each_unique"))
-			sha1_array_for_each_unique(&array, print_sha1, NULL);
+			oid_array_for_each_unique(&array, print_oid, NULL);
 		else
 			die("unknown command: %s", line.buf);
 	}
diff --git a/t/helper/test-strcmp-offset.c b/t/helper/test-strcmp-offset.c
new file mode 100644
index 0000000..4a45a54
--- /dev/null
+++ b/t/helper/test-strcmp-offset.c
@@ -0,0 +1,22 @@
+#include "cache.h"
+
+int cmd_main(int argc, const char **argv)
+{
+	int result;
+	size_t offset;
+
+	if (!argv[1] || !argv[2])
+		die("usage: %s <string1> <string2>", argv[0]);
+
+	result = strcmp_offset(argv[1], argv[2], &offset);
+
+	/*
+	 * Because differnt CRTs behave differently, only rely on signs
+	 * of the result values.
+	 */
+	result = (result < 0 ? -1 :
+			  result > 0 ? 1 :
+			  0);
+	printf("%d %"PRIuMAX"\n", result, (uintmax_t)offset);
+	return 0;
+}
diff --git a/t/perf/aggregate.perl b/t/perf/aggregate.perl
index 924b19d..1dbc85b 100755
--- a/t/perf/aggregate.perl
+++ b/t/perf/aggregate.perl
@@ -88,6 +88,7 @@
 sub read_descr {
 	my $name = shift;
 	open my $fh, "<", $name or return "<error reading description>";
+	binmode $fh, ":utf8" or die "PANIC on binmode: $!";
 	my $line = <$fh>;
 	close $fh or die "cannot close $name";
 	chomp $line;
@@ -147,6 +148,8 @@
 my $totalwidth = 3*@dirs+$descrlen;
 $totalwidth += $_ for (@colwidth);
 
+binmode STDOUT, ":utf8" or die "PANIC on binmode: $!";
+
 printf "%-${descrlen}s", "Test";
 for my $i (0..$#dirs) {
 	my $d = $dirs[$i];
diff --git a/t/perf/p0000-perf-lib-sanity.sh b/t/perf/p0000-perf-lib-sanity.sh
index cf8e1ef..002c21e 100755
--- a/t/perf/p0000-perf-lib-sanity.sh
+++ b/t/perf/p0000-perf-lib-sanity.sh
@@ -33,6 +33,8 @@
 	test_export bar
 '
 
+test_perf 'éḿíẗ Å„öÅ„-ÁŚĆÍÍ Ä‡á¸§áÅ•áćẗéÅ•Å›' 'true'
+
 test_expect_success 'test_export works with weird vars' '
 	echo "$bar" &&
 	test "$bar" = "weird # variable"
diff --git a/t/perf/p0004-lazy-init-name-hash.sh b/t/perf/p0004-lazy-init-name-hash.sh
old mode 100644
new mode 100755
diff --git a/t/perf/p0005-status.sh b/t/perf/p0005-status.sh
new file mode 100755
index 0000000..0b0aa98
--- /dev/null
+++ b/t/perf/p0005-status.sh
@@ -0,0 +1,49 @@
+#!/bin/sh
+#
+# This test measures the performance of various read-tree
+# and status operations.  It is primarily interested in
+# the algorithmic costs of index operations and recursive
+# tree traversal -- and NOT disk I/O on thousands of files.
+
+test_description="Tests performance of read-tree"
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+# If the test repo was generated by ./repos/many-files.sh
+# then we know something about the data shape and branches,
+# so we can isolate testing to the ballast-related commits
+# and setup sparse-checkout so we don't have to populate
+# the ballast files and directories.
+#
+# Otherwise, we make some general assumptions about the
+# repo and consider the entire history of the current
+# branch to be the ballast.
+
+test_expect_success "setup repo" '
+	if git rev-parse --verify refs/heads/p0006-ballast^{commit}
+	then
+		echo Assuming synthetic repo from many-files.sh
+		git branch br_base            master
+		git branch br_ballast         p0006-ballast
+		git config --local core.sparsecheckout 1
+		cat >.git/info/sparse-checkout <<-EOF
+		/*
+		!ballast/*
+		EOF
+	else
+		echo Assuming non-synthetic repo...
+		git branch br_base            $(git rev-list HEAD | tail -n 1)
+		git branch br_ballast         HEAD
+	fi &&
+	git checkout -q br_ballast &&
+	nr_files=$(git ls-files | wc -l)
+'
+
+test_perf "read-tree status br_ballast ($nr_files)" '
+	git read-tree HEAD &&
+	git status
+'
+
+test_done
diff --git a/t/perf/p0006-read-tree-checkout.sh b/t/perf/p0006-read-tree-checkout.sh
new file mode 100755
index 0000000..78cc23f
--- /dev/null
+++ b/t/perf/p0006-read-tree-checkout.sh
@@ -0,0 +1,67 @@
+#!/bin/sh
+#
+# This test measures the performance of various read-tree
+# and checkout operations.  It is primarily interested in
+# the algorithmic costs of index operations and recursive
+# tree traversal -- and NOT disk I/O on thousands of files.
+
+test_description="Tests performance of read-tree"
+
+. ./perf-lib.sh
+
+test_perf_default_repo
+
+# If the test repo was generated by ./repos/many-files.sh
+# then we know something about the data shape and branches,
+# so we can isolate testing to the ballast-related commits
+# and setup sparse-checkout so we don't have to populate
+# the ballast files and directories.
+#
+# Otherwise, we make some general assumptions about the
+# repo and consider the entire history of the current
+# branch to be the ballast.
+
+test_expect_success "setup repo" '
+	if git rev-parse --verify refs/heads/p0006-ballast^{commit}
+	then
+		echo Assuming synthetic repo from many-files.sh
+		git branch br_base            master
+		git branch br_ballast         p0006-ballast^
+		git branch br_ballast_alias   p0006-ballast^
+		git branch br_ballast_plus_1  p0006-ballast
+		git config --local core.sparsecheckout 1
+		cat >.git/info/sparse-checkout <<-EOF
+		/*
+		!ballast/*
+		EOF
+	else
+		echo Assuming non-synthetic repo...
+		git branch br_base            $(git rev-list HEAD | tail -n 1)
+		git branch br_ballast         HEAD^ || error "no ancestor commit from current head"
+		git branch br_ballast_alias   HEAD^
+		git branch br_ballast_plus_1  HEAD
+	fi &&
+	git checkout -q br_ballast &&
+	nr_files=$(git ls-files | wc -l)
+'
+
+test_perf "read-tree br_base br_ballast ($nr_files)" '
+	git read-tree -m br_base br_ballast -n
+'
+
+test_perf "switch between br_base br_ballast ($nr_files)" '
+	git checkout -q br_base &&
+	git checkout -q br_ballast
+'
+
+test_perf "switch between br_ballast br_ballast_plus_1 ($nr_files)" '
+	git checkout -q br_ballast_plus_1 &&
+	git checkout -q br_ballast
+'
+
+test_perf "switch between aliases ($nr_files)" '
+	git checkout -q br_ballast_alias &&
+	git checkout -q br_ballast
+'
+
+test_done
diff --git a/t/perf/repos/.gitignore b/t/perf/repos/.gitignore
new file mode 100644
index 0000000..72e3dc3
--- /dev/null
+++ b/t/perf/repos/.gitignore
@@ -0,0 +1 @@
+gen-*/
diff --git a/t/perf/repos/inflate-repo.sh b/t/perf/repos/inflate-repo.sh
new file mode 100755
index 0000000..fcfc992
--- /dev/null
+++ b/t/perf/repos/inflate-repo.sh
@@ -0,0 +1,85 @@
+#!/bin/sh
+# Inflate the size of an EXISTING repo.
+#
+# This script should be run inside the worktree of a TEST repo.
+# It will use the contents of the current HEAD to generate a
+# commit containing copies of the current worktree such that the
+# total size of the commit has at least <target_size> files.
+#
+# Usage: [-t target_size] [-b branch_name]
+
+set -e
+
+target_size=10000
+branch_name=p0006-ballast
+ballast=ballast
+
+while test "$#" -ne 0
+do
+    case "$1" in
+	-b)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -b requires an argument' >&2; exit 1; }
+	    branch_name=$1;
+	    shift ;;
+	-t)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -t requires an argument' >&2; exit 1; }
+	    target_size=$1;
+	    shift ;;
+	*)
+	    echo "error: unknown option '$1'" >&2; exit 1 ;;
+    esac
+done
+
+git ls-tree -r HEAD >GEN_src_list
+nr_src_files=$(cat GEN_src_list | wc -l)
+
+src_branch=$(git symbolic-ref --short HEAD)
+
+echo "Branch $src_branch initially has $nr_src_files files."
+
+if test $target_size -le $nr_src_files
+then
+    echo "Repository already exceeds target size $target_size."
+    rm GEN_src_list
+    exit 1
+fi
+
+# Create well-known branch and add 1 file change to start
+# if off before the ballast.
+git checkout -b $branch_name HEAD
+echo "$target_size" > inflate-repo.params
+git add inflate-repo.params
+git commit -q -m params
+
+# Create ballast for in our branch.
+copy=1
+nr_files=$nr_src_files
+while test $nr_files -lt $target_size
+do
+    sed -e "s|	|	$ballast/$copy/|" <GEN_src_list |
+	git update-index --index-info
+
+    nr_files=$(expr $nr_files + $nr_src_files)
+    copy=$(expr $copy + 1)
+done
+rm GEN_src_list
+git commit -q -m "ballast"
+
+# Modify 1 file and commit.
+echo "$target_size" >> inflate-repo.params
+git add inflate-repo.params
+git commit -q -m "ballast plus 1"
+
+nr_files=$(git ls-files | wc -l)
+
+# Checkout master to put repo in canonical state (because
+# the perf test may need to clone and enable sparse-checkout
+# before attempting to checkout a commit with the ballast
+# (because it may contain 100K directories and 1M files)).
+git checkout $src_branch
+
+echo "Repository inflated. Branch $branch_name has $nr_files files."
+
+exit 0
diff --git a/t/perf/repos/many-files.sh b/t/perf/repos/many-files.sh
new file mode 100755
index 0000000..28720e4
--- /dev/null
+++ b/t/perf/repos/many-files.sh
@@ -0,0 +1,110 @@
+#!/bin/sh
+# Generate test data repository using the given parameters.
+# When omitted, we create "gen-many-files-d-w-f.git".
+#
+# Usage: [-r repo] [-d depth] [-w width] [-f files]
+#
+# -r repo: path to the new repo to be generated
+# -d depth: the depth of sub-directories
+# -w width: the number of sub-directories at each level
+# -f files: the number of files created in each directory
+#
+# Note that all files will have the same SHA-1 and each
+# directory at a level will have the same SHA-1, so we
+# will potentially have a large index, but not a large
+# ODB.
+#
+# Ballast will be created under "ballast/".
+
+EMPTY_BLOB=e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
+
+set -e
+
+# (5, 10, 9) will create 999,999 ballast files.
+# (4, 10, 9) will create  99,999 ballast files.
+depth=5
+width=10
+files=9
+
+while test "$#" -ne 0
+do
+    case "$1" in
+	-r)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -r requires an argument' >&2; exit 1; }
+	    repo=$1;
+	    shift ;;
+	-d)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -d requires an argument' >&2; exit 1; }
+	    depth=$1;
+	    shift ;;
+	-w)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -w requires an argument' >&2; exit 1; }
+	    width=$1;
+	    shift ;;
+	-f)
+	    shift;
+	    test "$#" -ne 0 || { echo 'error: -f requires an argument' >&2; exit 1; }
+	    files=$1;
+	    shift ;;
+	*)
+	    echo "error: unknown option '$1'" >&2; exit 1 ;;
+	esac
+done
+
+# Inflate the index with thousands of empty files.
+# usage: dir depth width files
+fill_index() {
+	awk -v arg_dir=$1 -v arg_depth=$2 -v arg_width=$3 -v arg_files=$4 '
+		function make_paths(dir, depth, width, files, f, w) {
+			for (f = 1; f <= files; f++) {
+				print dir "/file" f
+			}
+			if (depth > 0) {
+				for (w = 1; w <= width; w++) {
+					make_paths(dir "/dir" w, depth - 1, width, files)
+				}
+			}
+		}
+		END { make_paths(arg_dir, arg_depth, arg_width, arg_files) }
+		' </dev/null |
+	sed "s/^/100644 $EMPTY_BLOB	/" |
+	git update-index --index-info
+	return 0
+}
+
+[ -z "$repo" ] && repo=gen-many-files-$depth.$width.$files.git
+
+mkdir $repo
+cd $repo
+git init .
+
+# Create an initial commit just to define master.
+touch many-files.empty
+echo "$depth $width $files" >many-files.params
+git add many-files.*
+git commit -q -m params
+
+# Create ballast for p0006 based upon the given params and
+# inflate the index with thousands of empty files and commit.
+git checkout -b p0006-ballast
+fill_index "ballast" $depth $width $files
+git commit -q -m "ballast"
+
+nr_files=$(git ls-files | wc -l)
+
+# Modify 1 file and commit.
+echo "$depth $width $files" >>many-files.params
+git add many-files.params
+git commit -q -m "ballast plus 1"
+
+# Checkout master to put repo in canonical state (because
+# the perf test may need to clone and enable sparse-checkout
+# before attempting to checkout a commit with the ballast
+# (because it may contain 100K directories and 1M files)).
+git checkout master
+
+echo "Repository "$repo" ($depth, $width, $files) created.  Ballast $nr_files."
+exit 0
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index e424de5..c4814d2 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -315,6 +315,20 @@
 	test_path_is_dir realgitdir/refs
 '
 
+test_expect_success 'init in long base path' '
+	# exceed initial buffer size of strbuf_getcwd()
+	component=123456789abcdef &&
+	test_when_finished "chmod 0700 $component; rm -rf $component" &&
+	p31=$component/$component &&
+	p127=$p31/$p31/$p31/$p31 &&
+	mkdir -p $p127 &&
+	chmod 0111 $component &&
+	(
+		cd $p127 &&
+		git init newdir
+	)
+'
+
 test_expect_success 're-init on .git file' '
 	( cd newdir && git init )
 '
diff --git a/t/t0025-crlf-auto.sh b/t/t0025-crlf-auto.sh
index d0bee08..89826c5 100755
--- a/t/t0025-crlf-auto.sh
+++ b/t/t0025-crlf-auto.sh
@@ -152,4 +152,30 @@
 	test -z "$LFwithNULdiff"
 '
 
+test_expect_success 'prepare unnormalized' '
+	> .gitattributes &&
+	git config core.autocrlf false &&
+	printf "LINEONE\nLINETWO\r\n"     >mixed &&
+	git add mixed .gitattributes &&
+	git commit -m "Add mixed" &&
+	git ls-files --eol | egrep "i/crlf" &&
+	git ls-files --eol | egrep "i/mixed"
+'
+
+test_expect_success 'normalize unnormalized' '
+	echo "* text=auto" >.gitattributes &&
+	rm .git/index &&
+	git add . &&
+	git commit -m "Introduce end-of-line normalization" &&
+	git ls-files --eol | tr "\\t" " " | sort >act &&
+cat >exp <<EOF &&
+i/-text w/-text attr/text=auto         LFwithNUL
+i/lf    w/crlf  attr/text=auto         CRLFonly
+i/lf    w/crlf  attr/text=auto         LFonly
+i/lf    w/lf    attr/text=auto         .gitattributes
+i/lf    w/mixed attr/text=auto         mixed
+EOF
+	test_cmp exp act
+'
+
 test_done
diff --git a/t/t0065-strcmp-offset.sh b/t/t0065-strcmp-offset.sh
new file mode 100755
index 0000000..7d6d214
--- /dev/null
+++ b/t/t0065-strcmp-offset.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+
+test_description='Test strcmp_offset functionality'
+
+. ./test-lib.sh
+
+while read s1 s2 expect
+do
+	test_expect_success "strcmp_offset($s1, $s2)" '
+		echo "$expect" >expect &&
+		test-strcmp-offset "$s1" "$s2" >actual &&
+		test_cmp expect actual
+	'
+done <<-EOF
+abc abc 0 3
+abc def -1 0
+abc abz -1 2
+abc abcdef -1 3
+EOF
+
+test_done
diff --git a/t/t1060-object-corruption.sh b/t/t1060-object-corruption.sh
index 3f87051..ac1f189 100755
--- a/t/t1060-object-corruption.sh
+++ b/t/t1060-object-corruption.sh
@@ -21,6 +21,14 @@
 		cd bit-error &&
 		test_commit content &&
 		corrupt_byte HEAD:content.t 10
+	) &&
+	git init no-bit-error &&
+	(
+		# distinct commit from bit-error, but containing a
+		# non-corrupted version of the same blob
+		cd no-bit-error &&
+		test_tick &&
+		test_commit content
 	)
 '
 
@@ -53,6 +61,13 @@
 	)
 '
 
+test_expect_success 'getting type of a corrupt blob fails' '
+	(
+		cd bit-error &&
+		test_must_fail git cat-file -s HEAD:content.t
+	)
+'
+
 test_expect_success 'read-tree -u detects bit-errors in blobs' '
 	(
 		cd bit-error &&
@@ -101,4 +116,13 @@
 	test_must_fail git clone --local misnamed misnamed-checkout
 '
 
+test_expect_success 'fetch into corrupted repo with index-pack' '
+	(
+		cd bit-error &&
+		test_must_fail git -c transfer.unpackLimit=1 \
+			fetch ../no-bit-error 2>stderr &&
+		test_i18ngrep ! -i collision stderr
+	)
+'
+
 test_done
diff --git a/t/t1305-config-include.sh b/t/t1305-config-include.sh
index e833939..933915e 100755
--- a/t/t1305-config-include.sh
+++ b/t/t1305-config-include.sh
@@ -3,6 +3,16 @@
 test_description='test config file include directives'
 . ./test-lib.sh
 
+# Force setup_explicit_git_dir() to run until the end. This is needed
+# by some tests to make sure real_path() is called on $GIT_DIR. The
+# caller needs to make sure git commands are run from a subdirectory
+# though or real_path() will not be called.
+force_setup_explicit_git_dir() {
+    GIT_DIR="$(pwd)/.git"
+    GIT_WORK_TREE="$(pwd)"
+    export GIT_DIR GIT_WORK_TREE
+}
+
 test_expect_success 'include file by absolute path' '
 	echo "[test]one = 1" >one &&
 	echo "[include]path = \"$(pwd)/one\"" >.gitconfig &&
@@ -208,6 +218,61 @@
 	)
 '
 
+test_expect_success 'conditional include, early config reading' '
+	(
+		cd foo &&
+		echo "[includeIf \"gitdir:foo/\"]path=bar6" >>.git/config &&
+		echo "[test]six=6" >.git/bar6 &&
+		echo 6 >expect &&
+		test-config read_early_config test.six >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success SYMLINKS 'conditional include, set up symlinked $HOME' '
+	mkdir real-home &&
+	ln -s real-home home &&
+	(
+		HOME="$TRASH_DIRECTORY/home" &&
+		export HOME &&
+		cd "$HOME" &&
+
+		git init foo &&
+		cd foo &&
+		mkdir sub
+	)
+'
+
+test_expect_success SYMLINKS 'conditional include, $HOME expansion with symlinks' '
+	(
+		HOME="$TRASH_DIRECTORY/home" &&
+		export HOME &&
+		cd "$HOME"/foo &&
+
+		echo "[includeIf \"gitdir:~/foo/\"]path=bar2" >>.git/config &&
+		echo "[test]two=2" >.git/bar2 &&
+		echo 2 >expect &&
+		force_setup_explicit_git_dir &&
+		git -C sub config test.two >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success SYMLINKS 'conditional include, relative path with symlinks' '
+	echo "[includeIf \"gitdir:./foo/.git\"]path=bar4" >home/.gitconfig &&
+	echo "[test]four=4" >home/bar4 &&
+	(
+		HOME="$TRASH_DIRECTORY/home" &&
+		export HOME &&
+		cd "$HOME"/foo &&
+
+		echo 4 >expect &&
+		force_setup_explicit_git_dir &&
+		git -C sub config test.four >actual &&
+		test_cmp expect actual
+	)
+'
+
 test_expect_success 'include cycles are detected' '
 	cat >.gitconfig <<-\EOF &&
 	[test]value = gitconfig
diff --git a/t/t1309-early-config.sh b/t/t1309-early-config.sh
index b97357b..1af8c45 100755
--- a/t/t1309-early-config.sh
+++ b/t/t1309-early-config.sh
@@ -47,6 +47,24 @@
 	test xdg = "$(cat output)"
 '
 
+cmdline_config="'test.source=cmdline'"
+test_expect_success 'read config file in right order' '
+	echo "[test]source = home" >>.gitconfig &&
+	git init foo &&
+	(
+		cd foo &&
+		echo "[test]source = repo" >>.git/config &&
+		GIT_CONFIG_PARAMETERS=$cmdline_config test-config \
+			read_early_config test.source >actual &&
+		cat >expected <<-\EOF &&
+		home
+		repo
+		cmdline
+		EOF
+		test_cmp expected actual
+	)
+'
+
 test_with_config () {
 	rm -rf throwaway &&
 	git init throwaway &&
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index a23cd7b..dc98b4b 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -35,14 +35,14 @@
 	cd -
 '
 
-test_expect_success \
-	"create $m" \
-	"git update-ref $m $A &&
-	 test $A"' = $(cat .git/'"$m"')'
-test_expect_success \
-	"create $m with oldvalue verification" \
-	"git update-ref $m $B $A &&
-	 test $B"' = $(cat .git/'"$m"')'
+test_expect_success "create $m" '
+	git update-ref $m $A &&
+	test $A = $(cat .git/$m)
+'
+test_expect_success "create $m with oldvalue verification" '
+	git update-ref $m $B $A &&
+	test $B = $(cat .git/$m)
+'
 test_expect_success "fail to delete $m with stale ref" '
 	test_must_fail git update-ref -d $m $A &&
 	test $B = "$(cat .git/$m)"
@@ -67,14 +67,14 @@
 	test_must_fail git update-ref $n $A
 '
 
-test_expect_success \
-	"create $m (by HEAD)" \
-	"git update-ref HEAD $A &&
-	 test $A"' = $(cat .git/'"$m"')'
-test_expect_success \
-	"create $m (by HEAD) with oldvalue verification" \
-	"git update-ref HEAD $B $A &&
-	 test $B"' = $(cat .git/'"$m"')'
+test_expect_success "create $m (by HEAD)" '
+	git update-ref HEAD $A &&
+	test $A = $(cat .git/$m)
+'
+test_expect_success "create $m (by HEAD) with oldvalue verification" '
+	git update-ref HEAD $B $A &&
+	test $B = $(cat .git/$m)
+'
 test_expect_success "fail to delete $m (by HEAD) with stale ref" '
 	test_must_fail git update-ref -d HEAD $A &&
 	test $B = $(cat .git/$m)
@@ -176,17 +176,17 @@
 	test_must_fail git reflog exists $outside
 '
 
-test_expect_success \
-	"create $m (by HEAD)" \
-	"git update-ref HEAD $A &&
-	 test $A"' = $(cat .git/'"$m"')'
-test_expect_success \
-	"pack refs" \
-	"git pack-refs --all"
-test_expect_success \
-	"move $m (by HEAD)" \
-	"git update-ref HEAD $B $A &&
-	 test $B"' = $(cat .git/'"$m"')'
+test_expect_success "create $m (by HEAD)" '
+	git update-ref HEAD $A &&
+	test $A = $(cat .git/$m)
+'
+test_expect_success 'pack refs' '
+	git pack-refs --all
+'
+test_expect_success "move $m (by HEAD)" '
+	git update-ref HEAD $B $A &&
+	test $B = $(cat .git/$m)
+'
 test_expect_success "delete $m (by HEAD) should remove both packed and loose $m" '
 	test_when_finished "rm -f .git/$m" &&
 	git update-ref -d HEAD $B &&
@@ -195,13 +195,13 @@
 '
 
 cp -f .git/HEAD .git/HEAD.orig
-test_expect_success "delete symref without dereference" '
+test_expect_success 'delete symref without dereference' '
 	test_when_finished "cp -f .git/HEAD.orig .git/HEAD" &&
 	git update-ref --no-deref -d HEAD &&
 	test_path_is_missing .git/HEAD
 '
 
-test_expect_success "delete symref without dereference when the referred ref is packed" '
+test_expect_success 'delete symref without dereference when the referred ref is packed' '
 	test_when_finished "cp -f .git/HEAD.orig .git/HEAD" &&
 	echo foo >foo.c &&
 	git add foo.c &&
@@ -239,46 +239,46 @@
 	test_path_is_missing .git/refs/heads/ref-to-bad
 '
 
-test_expect_success '(not) create HEAD with old sha1' "
+test_expect_success '(not) create HEAD with old sha1' '
 	test_must_fail git update-ref HEAD $A $B
-"
+'
 test_expect_success "(not) prior created .git/$m" '
 	test_when_finished "rm -f .git/$m" &&
 	test_path_is_missing .git/$m
 '
 
-test_expect_success \
-	"create HEAD" \
-	"git update-ref HEAD $A"
-test_expect_success '(not) change HEAD with wrong SHA1' "
+test_expect_success 'create HEAD' '
+	git update-ref HEAD $A
+'
+test_expect_success '(not) change HEAD with wrong SHA1' '
 	test_must_fail git update-ref HEAD $B $Z
-"
+'
 test_expect_success "(not) changed .git/$m" '
 	test_when_finished "rm -f .git/$m" &&
 	! test $B = $(cat .git/$m)
 '
 
 rm -f .git/logs/refs/heads/master
-test_expect_success \
-	"create $m (logged by touch)" \
-	'test_config core.logAllRefUpdates false &&
-	 GIT_COMMITTER_DATE="2005-05-26 23:30" \
-	 git update-ref --create-reflog HEAD '"$A"' -m "Initial Creation" &&
-	 test '"$A"' = $(cat .git/'"$m"')'
-test_expect_success \
-	"update $m (logged by touch)" \
-	'test_config core.logAllRefUpdates false &&
-	 GIT_COMMITTER_DATE="2005-05-26 23:31" \
-	 git update-ref HEAD'" $B $A "'-m "Switch" &&
-	 test '"$B"' = $(cat .git/'"$m"')'
-test_expect_success \
-	"set $m (logged by touch)" \
-	'test_config core.logAllRefUpdates false &&
-	 GIT_COMMITTER_DATE="2005-05-26 23:41" \
-	 git update-ref HEAD'" $A &&
-	 test $A"' = $(cat .git/'"$m"')'
+test_expect_success "create $m (logged by touch)" '
+	test_config core.logAllRefUpdates false &&
+	GIT_COMMITTER_DATE="2005-05-26 23:30" \
+	git update-ref --create-reflog HEAD $A -m "Initial Creation" &&
+	test $A = $(cat .git/$m)
+'
+test_expect_success "update $m (logged by touch)" '
+	test_config core.logAllRefUpdates false &&
+	GIT_COMMITTER_DATE="2005-05-26 23:31" \
+	git update-ref HEAD $B $A -m "Switch" &&
+	test $B = $(cat .git/$m)
+'
+test_expect_success "set $m (logged by touch)" '
+	test_config core.logAllRefUpdates false &&
+	GIT_COMMITTER_DATE="2005-05-26 23:41" \
+	git update-ref HEAD $A &&
+	test $A = $(cat .git/$m)
+'
 
-test_expect_success "empty directory removal" '
+test_expect_success 'empty directory removal' '
 	git branch d1/d2/r1 HEAD &&
 	git branch d1/r2 HEAD &&
 	test_path_is_file .git/refs/heads/d1/d2/r1 &&
@@ -290,7 +290,7 @@
 	test_path_is_file .git/logs/refs/heads/d1/r2
 '
 
-test_expect_success "symref empty directory removal" '
+test_expect_success 'symref empty directory removal' '
 	git branch e1/e2/r1 HEAD &&
 	git branch e1/r2 HEAD &&
 	git checkout e1/e2/r1 &&
@@ -315,34 +315,34 @@
 	test_cmp expect .git/logs/$m
 '
 
-test_expect_success \
-	"create $m (logged by config)" \
-	'test_config core.logAllRefUpdates true &&
-	 GIT_COMMITTER_DATE="2005-05-26 23:32" \
-	 git update-ref HEAD'" $A "'-m "Initial Creation" &&
-	 test '"$A"' = $(cat .git/'"$m"')'
-test_expect_success \
-	"update $m (logged by config)" \
-	'test_config core.logAllRefUpdates true &&
-	 GIT_COMMITTER_DATE="2005-05-26 23:33" \
-	 git update-ref HEAD'" $B $A "'-m "Switch" &&
-	 test '"$B"' = $(cat .git/'"$m"')'
-test_expect_success \
-	"set $m (logged by config)" \
-	'test_config core.logAllRefUpdates true &&
-	 GIT_COMMITTER_DATE="2005-05-26 23:43" \
-	 git update-ref HEAD '"$A &&
-	 test $A"' = $(cat .git/'"$m"')'
+test_expect_success "create $m (logged by config)" '
+	test_config core.logAllRefUpdates true &&
+	GIT_COMMITTER_DATE="2005-05-26 23:32" \
+	git update-ref HEAD $A -m "Initial Creation" &&
+	test $A = $(cat .git/$m)
+'
+test_expect_success "update $m (logged by config)" '
+	test_config core.logAllRefUpdates true &&
+	GIT_COMMITTER_DATE="2005-05-26 23:33" \
+	git update-ref HEAD'" $B $A "'-m "Switch" &&
+	test $B = $(cat .git/$m)
+'
+test_expect_success "set $m (logged by config)" '
+	test_config core.logAllRefUpdates true &&
+	GIT_COMMITTER_DATE="2005-05-26 23:43" \
+	git update-ref HEAD $A &&
+	test $A = $(cat .git/$m)
+'
 
 cat >expect <<EOF
 $Z $A $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150320 +0000	Initial Creation
 $A $B $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150380 +0000	Switch
 $B $A $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150980 +0000
 EOF
-test_expect_success \
-	"verifying $m's log (logged by config)" \
-	'test_when_finished "rm -f .git/$m .git/logs/$m expect" &&
-	 test_cmp expect .git/logs/$m'
+test_expect_success "verifying $m's log (logged by config)" '
+	test_when_finished "rm -f .git/$m .git/logs/$m expect" &&
+	test_cmp expect .git/logs/$m
+'
 
 git update-ref $m $D
 cat >.git/logs/$m <<EOF
@@ -356,86 +356,85 @@
 ed="Thu, 26 May 2005 18:32:00 -0500"
 gd="Thu, 26 May 2005 18:33:00 -0500"
 ld="Thu, 26 May 2005 18:43:00 -0500"
-test_expect_success \
-	'Query "master@{May 25 2005}" (before history)' \
-	'test_when_finished "rm -f o e" &&
-	 git rev-parse --verify "master@{May 25 2005}" >o 2>e &&
-	 test '"$C"' = $(cat o) &&
-	 test "warning: Log for '\'master\'' only goes back to $ed." = "$(cat e)"'
-test_expect_success \
-	"Query master@{2005-05-25} (before history)" \
-	'test_when_finished "rm -f o e" &&
-	 git rev-parse --verify master@{2005-05-25} >o 2>e &&
-	 test '"$C"' = $(cat o) &&
-	 echo test "warning: Log for '\'master\'' only goes back to $ed." = "$(cat e)"'
-test_expect_success \
-	'Query "master@{May 26 2005 23:31:59}" (1 second before history)' \
-	'test_when_finished "rm -f o e" &&
-	 git rev-parse --verify "master@{May 26 2005 23:31:59}" >o 2>e &&
-	 test '"$C"' = $(cat o) &&
-	 test "warning: Log for '\''master'\'' only goes back to $ed." = "$(cat e)"'
-test_expect_success \
-	'Query "master@{May 26 2005 23:32:00}" (exactly history start)' \
-	'test_when_finished "rm -f o e" &&
-	 git rev-parse --verify "master@{May 26 2005 23:32:00}" >o 2>e &&
-	 test '"$C"' = $(cat o) &&
-	 test "" = "$(cat e)"'
-test_expect_success \
-	'Query "master@{May 26 2005 23:32:30}" (first non-creation change)' \
-	'test_when_finished "rm -f o e" &&
-	 git rev-parse --verify "master@{May 26 2005 23:32:30}" >o 2>e &&
-	 test '"$A"' = $(cat o) &&
-	 test "" = "$(cat e)"'
-test_expect_success \
-	'Query "master@{2005-05-26 23:33:01}" (middle of history with gap)' \
-	'test_when_finished "rm -f o e" &&
-	 git rev-parse --verify "master@{2005-05-26 23:33:01}" >o 2>e &&
-	 test '"$B"' = $(cat o) &&
-	 test "warning: Log for ref '"$m has gap after $gd"'." = "$(cat e)"'
-test_expect_success \
-	'Query "master@{2005-05-26 23:38:00}" (middle of history)' \
-	'test_when_finished "rm -f o e" &&
-	 git rev-parse --verify "master@{2005-05-26 23:38:00}" >o 2>e &&
-	 test '"$Z"' = $(cat o) &&
-	 test "" = "$(cat e)"'
-test_expect_success \
-	'Query "master@{2005-05-26 23:43:00}" (exact end of history)' \
-	'test_when_finished "rm -f o e" &&
-	 git rev-parse --verify "master@{2005-05-26 23:43:00}" >o 2>e &&
-	 test '"$E"' = $(cat o) &&
-	 test "" = "$(cat e)"'
-test_expect_success \
-	'Query "master@{2005-05-28}" (past end of history)' \
-	'test_when_finished "rm -f o e" &&
-	 git rev-parse --verify "master@{2005-05-28}" >o 2>e &&
-	 test '"$D"' = $(cat o) &&
-	 test "warning: Log for ref '"$m unexpectedly ended on $ld"'." = "$(cat e)"'
-
+test_expect_success 'Query "master@{May 25 2005}" (before history)' '
+	test_when_finished "rm -f o e" &&
+	git rev-parse --verify "master@{May 25 2005}" >o 2>e &&
+	test $C = $(cat o) &&
+	test "warning: Log for '\''master'\'' only goes back to $ed." = "$(cat e)"
+'
+test_expect_success 'Query master@{2005-05-25} (before history)' '
+	test_when_finished "rm -f o e" &&
+	git rev-parse --verify master@{2005-05-25} >o 2>e &&
+	test $C = $(cat o) &&
+	echo test "warning: Log for '\''master'\'' only goes back to $ed." = "$(cat e)"
+'
+test_expect_success 'Query "master@{May 26 2005 23:31:59}" (1 second before history)' '
+	test_when_finished "rm -f o e" &&
+	git rev-parse --verify "master@{May 26 2005 23:31:59}" >o 2>e &&
+	test $C = $(cat o) &&
+	test "warning: Log for '\''master'\'' only goes back to $ed." = "$(cat e)"
+'
+test_expect_success 'Query "master@{May 26 2005 23:32:00}" (exactly history start)' '
+	test_when_finished "rm -f o e" &&
+	git rev-parse --verify "master@{May 26 2005 23:32:00}" >o 2>e &&
+	test $C = $(cat o) &&
+	test "" = "$(cat e)"
+'
+test_expect_success 'Query "master@{May 26 2005 23:32:30}" (first non-creation change)' '
+	test_when_finished "rm -f o e" &&
+	git rev-parse --verify "master@{May 26 2005 23:32:30}" >o 2>e &&
+	test $A = $(cat o) &&
+	test "" = "$(cat e)"
+'
+test_expect_success 'Query "master@{2005-05-26 23:33:01}" (middle of history with gap)' '
+	test_when_finished "rm -f o e" &&
+	git rev-parse --verify "master@{2005-05-26 23:33:01}" >o 2>e &&
+	test $B = $(cat o) &&
+	test "warning: Log for ref $m has gap after $gd." = "$(cat e)"
+'
+test_expect_success 'Query "master@{2005-05-26 23:38:00}" (middle of history)' '
+	test_when_finished "rm -f o e" &&
+	git rev-parse --verify "master@{2005-05-26 23:38:00}" >o 2>e &&
+	test $Z = $(cat o) &&
+	test "" = "$(cat e)"
+'
+test_expect_success 'Query "master@{2005-05-26 23:43:00}" (exact end of history)' '
+	test_when_finished "rm -f o e" &&
+	git rev-parse --verify "master@{2005-05-26 23:43:00}" >o 2>e &&
+	test $E = $(cat o) &&
+	test "" = "$(cat e)"
+'
+test_expect_success 'Query "master@{2005-05-28}" (past end of history)' '
+	test_when_finished "rm -f o e" &&
+	git rev-parse --verify "master@{2005-05-28}" >o 2>e &&
+	test $D = $(cat o) &&
+	test "warning: Log for ref $m unexpectedly ended on $ld." = "$(cat e)"
+'
 
 rm -f .git/$m .git/logs/$m expect
 
-test_expect_success \
-    'creating initial files' \
-    'test_when_finished rm -f M &&
-     echo TEST >F &&
-     git add F &&
-	 GIT_AUTHOR_DATE="2005-05-26 23:30" \
-	 GIT_COMMITTER_DATE="2005-05-26 23:30" git commit -m add -a &&
-	 h_TEST=$(git rev-parse --verify HEAD) &&
-	 echo The other day this did not work. >M &&
-	 echo And then Bob told me how to fix it. >>M &&
-	 echo OTHER >F &&
-	 GIT_AUTHOR_DATE="2005-05-26 23:41" \
-	 GIT_COMMITTER_DATE="2005-05-26 23:41" git commit -F M -a &&
-	 h_OTHER=$(git rev-parse --verify HEAD) &&
-	 GIT_AUTHOR_DATE="2005-05-26 23:44" \
-	 GIT_COMMITTER_DATE="2005-05-26 23:44" git commit --amend &&
-	 h_FIXED=$(git rev-parse --verify HEAD) &&
-	 echo Merged initial commit and a later commit. >M &&
-	 echo $h_TEST >.git/MERGE_HEAD &&
-	 GIT_AUTHOR_DATE="2005-05-26 23:45" \
-	 GIT_COMMITTER_DATE="2005-05-26 23:45" git commit -F M &&
-	 h_MERGED=$(git rev-parse --verify HEAD)'
+test_expect_success 'creating initial files' '
+	test_when_finished rm -f M &&
+	echo TEST >F &&
+	git add F &&
+	GIT_AUTHOR_DATE="2005-05-26 23:30" \
+	GIT_COMMITTER_DATE="2005-05-26 23:30" git commit -m add -a &&
+	h_TEST=$(git rev-parse --verify HEAD) &&
+	echo The other day this did not work. >M &&
+	echo And then Bob told me how to fix it. >>M &&
+	echo OTHER >F &&
+	GIT_AUTHOR_DATE="2005-05-26 23:41" \
+	GIT_COMMITTER_DATE="2005-05-26 23:41" git commit -F M -a &&
+	h_OTHER=$(git rev-parse --verify HEAD) &&
+	GIT_AUTHOR_DATE="2005-05-26 23:44" \
+	GIT_COMMITTER_DATE="2005-05-26 23:44" git commit --amend &&
+	h_FIXED=$(git rev-parse --verify HEAD) &&
+	echo Merged initial commit and a later commit. >M &&
+	echo $h_TEST >.git/MERGE_HEAD &&
+	GIT_AUTHOR_DATE="2005-05-26 23:45" \
+	GIT_COMMITTER_DATE="2005-05-26 23:45" git commit -F M &&
+	h_MERGED=$(git rev-parse --verify HEAD)
+'
 
 cat >expect <<EOF
 $Z $h_TEST $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	commit (initial): add
@@ -443,20 +442,20 @@
 $h_OTHER $h_FIXED $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117151040 +0000	commit (amend): The other day this did not work.
 $h_FIXED $h_MERGED $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117151100 +0000	commit (merge): Merged initial commit and a later commit.
 EOF
-test_expect_success \
-	'git commit logged updates' \
-	"test_cmp expect .git/logs/$m"
+test_expect_success 'git commit logged updates' '
+	test_cmp expect .git/logs/$m
+'
 unset h_TEST h_OTHER h_FIXED h_MERGED
 
-test_expect_success \
-	'git cat-file blob master:F (expect OTHER)' \
-	'test OTHER = $(git cat-file blob master:F)'
-test_expect_success \
-	'git cat-file blob master@{2005-05-26 23:30}:F (expect TEST)' \
-	'test TEST = $(git cat-file blob "master@{2005-05-26 23:30}:F")'
-test_expect_success \
-	'git cat-file blob master@{2005-05-26 23:42}:F (expect OTHER)' \
-	'test OTHER = $(git cat-file blob "master@{2005-05-26 23:42}:F")'
+test_expect_success 'git cat-file blob master:F (expect OTHER)' '
+	test OTHER = $(git cat-file blob master:F)
+'
+test_expect_success 'git cat-file blob master@{2005-05-26 23:30}:F (expect TEST)' '
+	test TEST = $(git cat-file blob "master@{2005-05-26 23:30}:F")
+'
+test_expect_success 'git cat-file blob master@{2005-05-26 23:42}:F (expect OTHER)' '
+	test OTHER = $(git cat-file blob "master@{2005-05-26 23:42}:F")
+'
 
 a=refs/heads/a
 b=refs/heads/b
diff --git a/t/t1405-main-ref-store.sh b/t/t1405-main-ref-store.sh
new file mode 100755
index 0000000..490521f
--- /dev/null
+++ b/t/t1405-main-ref-store.sh
@@ -0,0 +1,129 @@
+#!/bin/sh
+
+test_description='test main ref store api'
+
+. ./test-lib.sh
+
+RUN="test-ref-store main"
+
+test_expect_success 'pack_refs(PACK_REFS_ALL | PACK_REFS_PRUNE)' '
+	test_commit one &&
+	N=`find .git/refs -type f | wc -l` &&
+	test "$N" != 0 &&
+	$RUN pack-refs 3 &&
+	N=`find .git/refs -type f | wc -l`
+'
+
+test_expect_success 'peel_ref(new-tag)' '
+	git rev-parse HEAD >expected &&
+	git tag -a -m new-tag new-tag HEAD &&
+	$RUN peel-ref refs/tags/new-tag >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'create_symref(FOO, refs/heads/master)' '
+	$RUN create-symref FOO refs/heads/master nothing &&
+	echo refs/heads/master >expected &&
+	git symbolic-ref FOO >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'delete_refs(FOO, refs/tags/new-tag)' '
+	git rev-parse FOO -- &&
+	git rev-parse refs/tags/new-tag -- &&
+	$RUN delete-refs 0 FOO refs/tags/new-tag &&
+	test_must_fail git rev-parse FOO -- &&
+	test_must_fail git rev-parse refs/tags/new-tag --
+'
+
+test_expect_success 'rename_refs(master, new-master)' '
+	git rev-parse master >expected &&
+	$RUN rename-ref refs/heads/master refs/heads/new-master &&
+	git rev-parse new-master >actual &&
+	test_cmp expected actual &&
+	test_commit recreate-master
+'
+
+test_expect_success 'for_each_ref(refs/heads/)' '
+	$RUN for-each-ref refs/heads/ | cut -c 42- >actual &&
+	cat >expected <<-\EOF &&
+	master 0x0
+	new-master 0x0
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'for_each_ref() is sorted' '
+	$RUN for-each-ref refs/heads/ | cut -c 42- >actual &&
+	sort actual > expected &&
+	test_cmp expected actual
+'
+
+test_expect_success 'resolve_ref(new-master)' '
+	SHA1=`git rev-parse new-master` &&
+	echo "$SHA1 refs/heads/new-master 0x0" >expected &&
+	$RUN resolve-ref refs/heads/new-master 0 >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'verify_ref(new-master)' '
+	$RUN verify-ref refs/heads/new-master
+'
+
+test_expect_success 'for_each_reflog()' '
+	$RUN for-each-reflog | sort | cut -c 42- >actual &&
+	cat >expected <<-\EOF &&
+	HEAD 0x1
+	refs/heads/master 0x0
+	refs/heads/new-master 0x0
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'for_each_reflog_ent()' '
+	$RUN for-each-reflog-ent HEAD >actual &&
+	head -n1 actual | grep one &&
+	tail -n2 actual | head -n1 | grep recreate-master
+'
+
+test_expect_success 'for_each_reflog_ent_reverse()' '
+	$RUN for-each-reflog-ent-reverse HEAD >actual &&
+	head -n1 actual | grep recreate-master &&
+	tail -n2 actual | head -n1 | grep one
+'
+
+test_expect_success 'reflog_exists(HEAD)' '
+	$RUN reflog-exists HEAD
+'
+
+test_expect_success 'delete_reflog(HEAD)' '
+	$RUN delete-reflog HEAD &&
+	! test -f .git/logs/HEAD
+'
+
+test_expect_success 'create-reflog(HEAD)' '
+	$RUN create-reflog HEAD 1 &&
+	test -f .git/logs/HEAD
+'
+
+test_expect_success 'delete_ref(refs/heads/foo)' '
+	git checkout -b foo &&
+	FOO_SHA1=`git rev-parse foo` &&
+	git checkout --detach &&
+	test_commit bar-commit &&
+	git checkout -b bar &&
+	BAR_SHA1=`git rev-parse bar` &&
+	$RUN update-ref updating refs/heads/foo $BAR_SHA1 $FOO_SHA1 0 &&
+	echo $BAR_SHA1 >expected &&
+	git rev-parse refs/heads/foo >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'delete_ref(refs/heads/foo)' '
+	SHA1=`git rev-parse foo` &&
+	git checkout --detach &&
+	$RUN delete-ref msg refs/heads/foo $SHA1 0 &&
+	test_must_fail git rev-parse refs/heads/foo --
+'
+
+test_done
diff --git a/t/t1406-submodule-ref-store.sh b/t/t1406-submodule-ref-store.sh
new file mode 100755
index 0000000..13b5454
--- /dev/null
+++ b/t/t1406-submodule-ref-store.sh
@@ -0,0 +1,101 @@
+#!/bin/sh
+
+test_description='test submodule ref store api'
+
+. ./test-lib.sh
+
+RUN="test-ref-store submodule:sub"
+
+test_expect_success 'setup' '
+	git init sub &&
+	(
+		cd sub &&
+		test_commit first &&
+		git checkout -b new-master
+	)
+'
+
+test_expect_success 'pack_refs() not allowed' '
+	test_must_fail $RUN pack-refs 3
+'
+
+test_expect_success 'peel_ref(new-tag)' '
+	git -C sub rev-parse HEAD >expected &&
+	git -C sub tag -a -m new-tag new-tag HEAD &&
+	$RUN peel-ref refs/tags/new-tag >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'create_symref() not allowed' '
+	test_must_fail $RUN create-symref FOO refs/heads/master nothing
+'
+
+test_expect_success 'delete_refs() not allowed' '
+	test_must_fail $RUN delete-refs 0 FOO refs/tags/new-tag
+'
+
+test_expect_success 'rename_refs() not allowed' '
+	test_must_fail $RUN rename-ref refs/heads/master refs/heads/new-master
+'
+
+test_expect_success 'for_each_ref(refs/heads/)' '
+	$RUN for-each-ref refs/heads/ | cut -c 42- >actual &&
+	cat >expected <<-\EOF &&
+	master 0x0
+	new-master 0x0
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'for_each_ref() is sorted' '
+	$RUN for-each-ref refs/heads/ | cut -c 42- >actual &&
+	sort actual > expected &&
+	test_cmp expected actual
+'
+
+test_expect_success 'resolve_ref(master)' '
+	SHA1=`git -C sub rev-parse master` &&
+	echo "$SHA1 refs/heads/master 0x0" >expected &&
+	$RUN resolve-ref refs/heads/master 0 >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'verify_ref(new-master)' '
+	$RUN verify-ref refs/heads/new-master
+'
+
+test_expect_success 'for_each_reflog()' '
+	$RUN for-each-reflog | sort | cut -c 42- >actual &&
+	cat >expected <<-\EOF &&
+	HEAD 0x1
+	refs/heads/master 0x0
+	refs/heads/new-master 0x0
+	EOF
+	test_cmp expected actual
+'
+
+test_expect_success 'for_each_reflog_ent()' '
+	$RUN for-each-reflog-ent HEAD >actual && cat actual &&
+	head -n1 actual | grep first &&
+	tail -n2 actual | head -n1 | grep master.to.new
+'
+
+test_expect_success 'for_each_reflog_ent_reverse()' '
+	$RUN for-each-reflog-ent-reverse HEAD >actual &&
+	head -n1 actual | grep master.to.new &&
+	tail -n2 actual | head -n1 | grep first
+'
+
+test_expect_success 'reflog_exists(HEAD)' '
+	$RUN reflog-exists HEAD
+'
+
+test_expect_success 'delete_reflog() not allowed' '
+	test_must_fail $RUN delete-reflog HEAD
+'
+
+test_expect_success 'create-reflog() not allowed' '
+	test_must_fail $RUN create-reflog HEAD 1
+'
+
+test_done
diff --git a/t/t1507-rev-parse-upstream.sh b/t/t1507-rev-parse-upstream.sh
index 46ef1f2..b23c4e3 100755
--- a/t/t1507-rev-parse-upstream.sh
+++ b/t/t1507-rev-parse-upstream.sh
@@ -46,11 +46,14 @@
 }
 
 test_expect_success '@{upstream} resolves to correct full name' '
-	test refs/remotes/origin/master = "$(full_name @{upstream})"
+	test refs/remotes/origin/master = "$(full_name @{upstream})" &&
+	test refs/remotes/origin/master = "$(full_name @{UPSTREAM})" &&
+	test refs/remotes/origin/master = "$(full_name @{UpSTReam})"
 '
 
 test_expect_success '@{u} resolves to correct full name' '
-	test refs/remotes/origin/master = "$(full_name @{u})"
+	test refs/remotes/origin/master = "$(full_name @{u})" &&
+	test refs/remotes/origin/master = "$(full_name @{U})"
 '
 
 test_expect_success 'my-side@{upstream} resolves to correct full name' '
@@ -60,6 +63,8 @@
 test_expect_success 'upstream of branch with @ in middle' '
 	full_name fun@ny@{u} >actual &&
 	echo refs/remotes/origin/side >expect &&
+	test_cmp expect actual &&
+	full_name fun@ny@{U} >actual &&
 	test_cmp expect actual
 '
 
@@ -96,12 +101,14 @@
 test_expect_success '<branch>@{u}@{1} resolves correctly' '
 	test_commit 6 &&
 	(cd clone && git fetch) &&
-	test 5 = $(commit_subject my-side@{u}@{1})
+	test 5 = $(commit_subject my-side@{u}@{1}) &&
+	test 5 = $(commit_subject my-side@{U}@{1})
 '
 
 test_expect_success '@{u} without specifying branch fails on a detached HEAD' '
 	git checkout HEAD^0 &&
-	test_must_fail git rev-parse @{u}
+	test_must_fail git rev-parse @{u} &&
+	test_must_fail git rev-parse @{U}
 '
 
 test_expect_success 'checkout -b new my-side@{u} forks from the same' '
diff --git a/t/t1514-rev-parse-push.sh b/t/t1514-rev-parse-push.sh
index 623a32a..788cc91 100755
--- a/t/t1514-rev-parse-push.sh
+++ b/t/t1514-rev-parse-push.sh
@@ -24,12 +24,16 @@
 
 test_expect_success '@{push} with default=nothing' '
 	test_config push.default nothing &&
-	test_must_fail git rev-parse master@{push}
+	test_must_fail git rev-parse master@{push} &&
+	test_must_fail git rev-parse master@{PUSH} &&
+	test_must_fail git rev-parse master@{PuSH}
 '
 
 test_expect_success '@{push} with default=simple' '
 	test_config push.default simple &&
-	resolve master@{push} refs/remotes/origin/master
+	resolve master@{push} refs/remotes/origin/master &&
+	resolve master@{PUSH} refs/remotes/origin/master &&
+	resolve master@{pUSh} refs/remotes/origin/master
 '
 
 test_expect_success 'triangular @{push} fails with default=simple' '
diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
index b618d6b..b5c47ac 100755
--- a/t/t2025-worktree-add.sh
+++ b/t/t2025-worktree-add.sh
@@ -63,6 +63,12 @@
 	)
 '
 
+test_expect_success '"add" worktree with lock' '
+	git rev-parse HEAD >expect &&
+	git worktree add --detach --lock here-with-lock master &&
+	test -f .git/worktrees/here-with-lock/locked
+'
+
 test_expect_success '"add" worktree from a subdir' '
 	(
 		mkdir sub &&
diff --git a/t/t2027-worktree-list.sh b/t/t2027-worktree-list.sh
index 848da5f..720063b 100755
--- a/t/t2027-worktree-list.sh
+++ b/t/t2027-worktree-list.sh
@@ -20,7 +20,7 @@
 
 test_expect_success 'rev-parse --git-path objects linked worktree' '
 	echo "$(git rev-parse --show-toplevel)/.git/objects" >expect &&
-	test_when_finished "rm -rf linked-tree && git worktree prune" &&
+	test_when_finished "rm -rf linked-tree actual expect && git worktree prune" &&
 	git worktree add --detach linked-tree master &&
 	git -C linked-tree rev-parse --git-path objects >actual &&
 	test_cmp expect actual
@@ -28,19 +28,21 @@
 
 test_expect_success '"list" all worktrees from main' '
 	echo "$(git rev-parse --show-toplevel) $(git rev-parse --short HEAD) [$(git symbolic-ref --short HEAD)]" >expect &&
-	test_when_finished "rm -rf here && git worktree prune" &&
+	test_when_finished "rm -rf here out actual expect && git worktree prune" &&
 	git worktree add --detach here master &&
 	echo "$(git -C here rev-parse --show-toplevel) $(git rev-parse --short HEAD) (detached HEAD)" >>expect &&
-	git worktree list | sed "s/  */ /g" >actual &&
+	git worktree list >out &&
+	sed "s/  */ /g" <out >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success '"list" all worktrees from linked' '
 	echo "$(git rev-parse --show-toplevel) $(git rev-parse --short HEAD) [$(git symbolic-ref --short HEAD)]" >expect &&
-	test_when_finished "rm -rf here && git worktree prune" &&
+	test_when_finished "rm -rf here out actual expect && git worktree prune" &&
 	git worktree add --detach here master &&
 	echo "$(git -C here rev-parse --show-toplevel) $(git rev-parse --short HEAD) (detached HEAD)" >>expect &&
-	git -C here worktree list | sed "s/  */ /g" >actual &&
+	git -C here worktree list >out &&
+	sed "s/  */ /g" <out >actual &&
 	test_cmp expect actual
 '
 
@@ -49,7 +51,7 @@
 	echo "HEAD $(git rev-parse HEAD)" >>expect &&
 	echo "branch $(git symbolic-ref HEAD)" >>expect &&
 	echo >>expect &&
-	test_when_finished "rm -rf here && git worktree prune" &&
+	test_when_finished "rm -rf here actual expect && git worktree prune" &&
 	git worktree add --detach here master &&
 	echo "worktree $(git -C here rev-parse --show-toplevel)" >>expect &&
 	echo "HEAD $(git rev-parse HEAD)" >>expect &&
@@ -69,16 +71,17 @@
 '
 
 test_expect_success '"list" all worktrees from bare main' '
-	test_when_finished "rm -rf there && git -C bare1 worktree prune" &&
+	test_when_finished "rm -rf there out actual expect && git -C bare1 worktree prune" &&
 	git -C bare1 worktree add --detach ../there master &&
 	echo "$(pwd)/bare1 (bare)" >expect &&
 	echo "$(git -C there rev-parse --show-toplevel) $(git -C there rev-parse --short HEAD) (detached HEAD)" >>expect &&
-	git -C bare1 worktree list | sed "s/  */ /g" >actual &&
+	git -C bare1 worktree list >out &&
+	sed "s/  */ /g" <out >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success '"list" all worktrees --porcelain from bare main' '
-	test_when_finished "rm -rf there && git -C bare1 worktree prune" &&
+	test_when_finished "rm -rf there actual expect && git -C bare1 worktree prune" &&
 	git -C bare1 worktree add --detach ../there master &&
 	echo "worktree $(pwd)/bare1" >expect &&
 	echo "bare" >>expect &&
@@ -92,11 +95,12 @@
 '
 
 test_expect_success '"list" all worktrees from linked with a bare main' '
-	test_when_finished "rm -rf there && git -C bare1 worktree prune" &&
+	test_when_finished "rm -rf there out actual expect && git -C bare1 worktree prune" &&
 	git -C bare1 worktree add --detach ../there master &&
 	echo "$(pwd)/bare1 (bare)" >expect &&
 	echo "$(git -C there rev-parse --show-toplevel) $(git -C there rev-parse --short HEAD) (detached HEAD)" >>expect &&
-	git -C there worktree list | sed "s/  */ /g" >actual &&
+	git -C there worktree list >out &&
+	sed "s/  */ /g" <out >actual &&
 	test_cmp expect actual
 '
 
@@ -118,9 +122,11 @@
 		cd linked &&
 		echo "worktree $(pwd)" >expected &&
 		echo "ref: .broken" >../.git/HEAD &&
-		git worktree list --porcelain | head -n 3 >actual &&
+		git worktree list --porcelain >out &&
+		head -n 3 out >actual &&
 		test_cmp ../expected actual &&
-		git worktree list | head -n 1 >actual.2 &&
+		git worktree list >out &&
+		head -n 1 out >actual.2 &&
 		grep -F "(error)" actual.2
 	)
 '
@@ -134,7 +140,8 @@
 		test_commit new &&
 		git worktree add ../first &&
 		git worktree add ../second &&
-		git worktree list --porcelain | grep ^worktree >actual
+		git worktree list --porcelain >out &&
+		grep ^worktree out >actual
 	) &&
 	cat >expected <<-EOF &&
 	worktree $(pwd)/sorted/main
diff --git a/t/t3007-ls-files-recurse-submodules.sh b/t/t3007-ls-files-recurse-submodules.sh
index a542617..ebb956f 100755
--- a/t/t3007-ls-files-recurse-submodules.sh
+++ b/t/t3007-ls-files-recurse-submodules.sh
@@ -77,10 +77,22 @@
 	git -C submodule/subsub commit -m "add d" &&
 	git -C submodule submodule add ./subsub &&
 	git -C submodule commit -m "added subsub" &&
+	git submodule absorbgitdirs &&
 	git ls-files --recurse-submodules >actual &&
 	test_cmp expect actual
 '
 
+test_expect_success 'ls-files works with GIT_DIR' '
+	cat >expect <<-\EOF &&
+	.gitmodules
+	c
+	subsub/d
+	EOF
+
+	git --git-dir=submodule/.git ls-files --recurse-submodules >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success '--recurse-submodules and pathspecs setup' '
 	echo e >submodule/subsub/e.txt &&
 	git -C submodule/subsub add e.txt &&
@@ -188,6 +200,45 @@
 	test_cmp expect actual
 '
 
+test_expect_success '--recurse-submodules and relative paths' '
+	# From subdir
+	cat >expect <<-\EOF &&
+	b
+	EOF
+	git -C b ls-files --recurse-submodules >actual &&
+	test_cmp expect actual &&
+
+	# Relative path to top
+	cat >expect <<-\EOF &&
+	../.gitmodules
+	../a
+	b
+	../h.txt
+	../sib/file
+	../sub/file
+	../submodule/.gitmodules
+	../submodule/c
+	../submodule/f.TXT
+	../submodule/g.txt
+	../submodule/subsub/d
+	../submodule/subsub/e.txt
+	EOF
+	git -C b ls-files --recurse-submodules -- .. >actual &&
+	test_cmp expect actual &&
+
+	# Relative path to submodule
+	cat >expect <<-\EOF &&
+	../submodule/.gitmodules
+	../submodule/c
+	../submodule/f.TXT
+	../submodule/g.txt
+	../submodule/subsub/d
+	../submodule/subsub/e.txt
+	EOF
+	git -C b ls-files --recurse-submodules -- ../submodule >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success '--recurse-submodules does not support --error-unmatch' '
 	test_must_fail git ls-files --recurse-submodules --error-unmatch 2>actual &&
 	test_i18ngrep "does not support --error-unmatch" actual
diff --git a/t/t3008-ls-files-lazy-init-name-hash.sh b/t/t3008-ls-files-lazy-init-name-hash.sh
new file mode 100755
index 0000000..bdf5198
--- /dev/null
+++ b/t/t3008-ls-files-lazy-init-name-hash.sh
@@ -0,0 +1,27 @@
+#!/bin/sh
+
+test_description='Test the lazy init name hash with various folder structures'
+
+. ./test-lib.sh
+
+if test 1 -eq $($GIT_BUILD_DIR/t/helper/test-online-cpus)
+then
+	skip_all='skipping lazy-init tests, single cpu'
+	test_done
+fi
+
+LAZY_THREAD_COST=2000
+
+test_expect_success 'no buffer overflow in lazy_init_name_hash' '
+	(
+	    test_seq $LAZY_THREAD_COST | sed "s/^/a_/"
+	    echo b/b/b
+	    test_seq $LAZY_THREAD_COST | sed "s/^/c_/"
+	    test_seq 50 | sed "s/^/d_/" | tr "\n" "/"; echo d
+	) |
+	sed "s/^/100644 $EMPTY_BLOB	/" |
+	git update-index --index-info &&
+	test-lazy-init-name-hash -m
+'
+
+test_done
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 9f353c0..fe62e7c 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -978,6 +978,10 @@
 	test_must_fail git branch --merged 0000000000000000000000000000000000000000
 '
 
+test_expect_success '--merged is incompatible with --no-merged' '
+	test_must_fail git branch --merged HEAD --no-merged HEAD
+'
+
 test_expect_success 'tracking with unexpected .fetch refspec' '
 	rm -rf a b c d &&
 	git init a &&
diff --git a/t/t3201-branch-contains.sh b/t/t3201-branch-contains.sh
index 7f3ec47..0ef1b6f 100755
--- a/t/t3201-branch-contains.sh
+++ b/t/t3201-branch-contains.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-test_description='branch --contains <commit>, --merged, and --no-merged'
+test_description='branch --contains <commit>, --no-contains <commit> --merged, and --no-merged'
 
 . ./test-lib.sh
 
@@ -45,6 +45,22 @@
 
 '
 
+test_expect_success 'branch --no-contains=master' '
+
+	git branch --no-contains=master >actual &&
+	>expect &&
+	test_cmp expect actual
+
+'
+
+test_expect_success 'branch --no-contains master' '
+
+	git branch --no-contains master >actual &&
+	>expect &&
+	test_cmp expect actual
+
+'
+
 test_expect_success 'branch --contains=side' '
 
 	git branch --contains=side >actual &&
@@ -55,6 +71,16 @@
 
 '
 
+test_expect_success 'branch --no-contains=side' '
+
+	git branch --no-contains=side >actual &&
+	{
+		echo "  master"
+	} >expect &&
+	test_cmp expect actual
+
+'
+
 test_expect_success 'branch --contains with pattern implies --list' '
 
 	git branch --contains=master master >actual &&
@@ -65,6 +91,14 @@
 
 '
 
+test_expect_success 'branch --no-contains with pattern implies --list' '
+
+	git branch --no-contains=master master >actual &&
+	>expect &&
+	test_cmp expect actual
+
+'
+
 test_expect_success 'side: branch --merged' '
 
 	git branch --merged >actual &&
@@ -126,10 +160,22 @@
 test_expect_success 'implicit --list conflicts with modification options' '
 
 	test_must_fail git branch --contains=master -d &&
-	test_must_fail git branch --contains=master -m foo
+	test_must_fail git branch --contains=master -m foo &&
+	test_must_fail git branch --no-contains=master -d &&
+	test_must_fail git branch --no-contains=master -m foo
 
 '
 
+test_expect_success 'Assert that --contains only works on commits, not trees & blobs' '
+	test_must_fail git branch --contains master^{tree} &&
+	blob=$(git hash-object -w --stdin <<-\EOF
+	Some blob
+	EOF
+	) &&
+	test_must_fail git branch --contains $blob &&
+	test_must_fail git branch --no-contains $blob
+'
+
 # We want to set up a case where the walk for the tracking info
 # of one branch crosses the tip of another branch (and make sure
 # that the latter walk does not mess up our flag to see if it was
@@ -159,4 +205,15 @@
 	test_i18ncmp expect actual
 '
 
+test_expect_success 'branch --contains combined with --no-contains' '
+	git branch --contains zzz --no-contains topic >actual &&
+	cat >expect <<-\EOF &&
+	  master
+	  side
+	  zzz
+	EOF
+	test_cmp expect actual
+
+'
+
 test_done
diff --git a/t/t3428-rebase-signoff.sh b/t/t3428-rebase-signoff.sh
new file mode 100755
index 0000000..2afb564
--- /dev/null
+++ b/t/t3428-rebase-signoff.sh
@@ -0,0 +1,46 @@
+#!/bin/sh
+
+test_description='git rebase --signoff
+
+This test runs git rebase --signoff and make sure that it works.
+'
+
+. ./test-lib.sh
+
+# A simple file to commit
+cat >file <<EOF
+a
+EOF
+
+# Expected commit message after rebase --signoff
+cat >expected-signed <<EOF
+first
+
+Signed-off-by: $(git var GIT_COMMITTER_IDENT | sed -e "s/>.*/>/")
+EOF
+
+# Expected commit message after rebase without --signoff (or with --no-signoff)
+cat >expected-unsigned <<EOF
+first
+EOF
+
+
+# We configure an alias to do the rebase --signoff so that
+# on the next subtest we can show that --no-signoff overrides the alias
+test_expect_success 'rebase --signoff adds a sign-off line' '
+	git commit --allow-empty -m "Initial empty commit" &&
+	git add file && git commit -m first &&
+	git config alias.rbs "rebase --signoff" &&
+	git rbs HEAD^ &&
+	git cat-file commit HEAD | sed -e "1,/^\$/d" > actual &&
+	test_cmp expected-signed actual
+'
+
+test_expect_success 'rebase --no-signoff does not add a sign-off line' '
+	git commit --amend -m "first" &&
+	git rbs --no-signoff HEAD^ &&
+	git cat-file commit HEAD | sed -e "1,/^\$/d" > actual &&
+	test_cmp expected-unsigned actual
+'
+
+test_done
diff --git a/t/t3429-rebase-edit-todo.sh b/t/t3429-rebase-edit-todo.sh
new file mode 100755
index 0000000..b9292df
--- /dev/null
+++ b/t/t3429-rebase-edit-todo.sh
@@ -0,0 +1,14 @@
+#!/bin/sh
+
+test_description='rebase should reread the todo file if an exec modifies it'
+
+. ./test-lib.sh
+
+test_expect_success 'rebase exec modifies rebase-todo' '
+	test_commit initial &&
+	todo=.git/rebase-merge/git-rebase-todo &&
+	git rebase HEAD -x "echo exec touch F >>$todo" &&
+	test -e F
+'
+
+test_done
diff --git a/t/t3600-rm.sh b/t/t3600-rm.sh
index 3c63455..5f9913b 100755
--- a/t/t3600-rm.sh
+++ b/t/t3600-rm.sh
@@ -268,6 +268,14 @@
  M submod
 EOF
 
+cat >expect.modified_inside <<EOF
+ m submod
+EOF
+
+cat >expect.modified_untracked <<EOF
+ ? submod
+EOF
+
 cat >expect.cached <<EOF
 D  submod
 EOF
@@ -421,7 +429,7 @@
 	test -d submod &&
 	test -f submod/.git &&
 	git status -s -uno --ignore-submodules=none >actual &&
-	test_cmp expect.modified actual &&
+	test_cmp expect.modified_inside actual &&
 	git rm -f submod &&
 	test ! -d submod &&
 	git status -s -uno --ignore-submodules=none >actual &&
@@ -436,7 +444,7 @@
 	test -d submod &&
 	test -f submod/.git &&
 	git status -s -uno --ignore-submodules=none >actual &&
-	test_cmp expect.modified actual &&
+	test_cmp expect.modified_untracked actual &&
 	git rm -f submod &&
 	test ! -d submod &&
 	git status -s -uno --ignore-submodules=none >actual &&
@@ -621,7 +629,7 @@
 	test -d submod &&
 	test -f submod/.git &&
 	git status -s -uno --ignore-submodules=none >actual &&
-	test_cmp expect.modified actual &&
+	test_cmp expect.modified_inside actual &&
 	git rm -f submod &&
 	test ! -d submod &&
 	git status -s -uno --ignore-submodules=none >actual &&
@@ -636,7 +644,7 @@
 	test -d submod &&
 	test -f submod/.git &&
 	git status -s -uno --ignore-submodules=none >actual &&
-	test_cmp expect.modified actual &&
+	test_cmp expect.modified_inside actual &&
 	git rm -f submod &&
 	test ! -d submod &&
 	git status -s -uno --ignore-submodules=none >actual &&
@@ -651,7 +659,7 @@
 	test -d submod &&
 	test -f submod/.git &&
 	git status -s -uno --ignore-submodules=none >actual &&
-	test_cmp expect.modified actual &&
+	test_cmp expect.modified_untracked actual &&
 	git rm -f submod &&
 	test ! -d submod &&
 	git status -s -uno --ignore-submodules=none >actual &&
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index f9528fa..2ecb43a 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -436,6 +436,28 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'add -p handles relative paths' '
+	git reset --hard &&
+
+	echo base >relpath.c &&
+	git add "*.c" &&
+	git commit -m relpath &&
+
+	echo change >relpath.c &&
+	mkdir -p subdir &&
+	git -C subdir add -p .. 2>error <<-\EOF &&
+	y
+	EOF
+
+	test_must_be_empty error &&
+
+	cat >expect <<-\EOF &&
+	relpath.c
+	EOF
+	git diff --cached --name-only >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'add -p does not expand argument lists' '
 	git reset --hard &&
 
diff --git a/t/t4060-diff-submodule-option-diff-format.sh b/t/t4060-diff-submodule-option-diff-format.sh
index 7e23b55..d4a3ffa 100755
--- a/t/t4060-diff-submodule-option-diff-format.sh
+++ b/t/t4060-diff-submodule-option-diff-format.sh
@@ -746,4 +746,33 @@
 	test_cmp expected actual
 '
 
+test_expect_success 'setup nested submodule' '
+	git submodule add -f ./sm2 &&
+	git commit -a -m "add sm2" &&
+	git -C sm2 submodule add ../sm2 nested &&
+	git -C sm2 commit -a -m "nested sub"
+'
+
+test_expect_success 'move nested submodule HEAD' '
+	echo "nested content" >sm2/nested/file &&
+	git -C sm2/nested add file &&
+	git -C sm2/nested commit --allow-empty -m "new HEAD"
+'
+
+test_expect_success 'diff --submodule=diff with moved nested submodule HEAD' '
+	cat >expected <<-EOF &&
+	Submodule nested a5a65c9..b55928c:
+	diff --git a/nested/file b/nested/file
+	new file mode 100644
+	index 0000000..ca281f5
+	--- /dev/null
+	+++ b/nested/file
+	@@ -0,0 +1 @@
+	+nested content
+	EOF
+	git -C sm2 diff --submodule=diff >actual 2>err &&
+	test_must_be_empty err &&
+	test_cmp expected actual
+'
+
 test_done
diff --git a/t/t4150-am.sh b/t/t4150-am.sh
index 89a5bac..44807e2 100755
--- a/t/t4150-am.sh
+++ b/t/t4150-am.sh
@@ -983,7 +983,9 @@
 	rm -fr .git/rebase-apply &&
 	git checkout -f first &&
 	echo one >> file &&
-	git commit -am "$LONG" --author="$LONG <long@example.com>" &&
+	git commit -am "$LONG
+
+    Body test" --author="$LONG <long@example.com>" &&
 	git format-patch --stdout -1 >patch &&
 	# bump from, date, and subject down to in-body header
 	perl -lpe "
@@ -997,7 +999,7 @@
 	git am msg &&
 	# Ensure that the author and full message are present
 	git cat-file commit HEAD | grep "^author.*long@example.com" &&
-	git cat-file commit HEAD | grep "^$LONG"
+	git cat-file commit HEAD | grep "^$LONG$"
 '
 
 test_done
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 48b55bf..f577990 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -4,6 +4,7 @@
 
 . ./test-lib.sh
 . "$TEST_DIRECTORY/lib-gpg.sh"
+. "$TEST_DIRECTORY/lib-terminal.sh"
 
 test_expect_success setup '
 
@@ -520,7 +521,7 @@
 '
 
 test_expect_success 'log.decorate configuration' '
-	git log --oneline >expect.none &&
+	git log --oneline --no-decorate >expect.none &&
 	git log --oneline --decorate >expect.short &&
 	git log --oneline --decorate=full >expect.full &&
 
@@ -576,6 +577,13 @@
 
 '
 
+test_expect_success TTY 'log output on a TTY' '
+	git log --oneline --decorate >expect.short &&
+
+	test_terminal git log --oneline >actual &&
+	test_cmp expect.short actual
+'
+
 test_expect_success 'reflog is expected format' '
 	git log -g --abbrev-commit --pretty=oneline >expect &&
 	git reflog >actual &&
diff --git a/t/t5531-deep-submodule-push.sh b/t/t5531-deep-submodule-push.sh
index f55137f..57ba322 100755
--- a/t/t5531-deep-submodule-push.sh
+++ b/t/t5531-deep-submodule-push.sh
@@ -475,4 +475,56 @@
 	test_cmp expected_pub actual_pub
 '
 
+test_expect_success 'push propagating the remotes name to a submodule' '
+	git -C work remote add origin ../pub.git &&
+	git -C work remote add pub ../pub.git &&
+
+	> work/gar/bage/junk10 &&
+	git -C work/gar/bage add junk10 &&
+	git -C work/gar/bage commit -m "Tenth junk" &&
+	git -C work add gar/bage &&
+	git -C work commit -m "Tenth junk added to gar/bage" &&
+
+	# Fails when submodule does not have a matching remote
+	test_must_fail git -C work push --recurse-submodules=on-demand pub master &&
+	# Succeeds when submodules has matching remote and refspec
+	git -C work push --recurse-submodules=on-demand origin master &&
+
+	git -C submodule.git rev-parse master >actual_submodule &&
+	git -C pub.git rev-parse master >actual_pub &&
+	git -C work/gar/bage rev-parse master >expected_submodule &&
+	git -C work rev-parse master >expected_pub &&
+	test_cmp expected_submodule actual_submodule &&
+	test_cmp expected_pub actual_pub
+'
+
+test_expect_success 'push propagating refspec to a submodule' '
+	> work/gar/bage/junk11 &&
+	git -C work/gar/bage add junk11 &&
+	git -C work/gar/bage commit -m "Eleventh junk" &&
+
+	git -C work checkout branch2 &&
+	git -C work add gar/bage &&
+	git -C work commit -m "updating gar/bage in branch2" &&
+
+	# Fails when submodule does not have a matching branch
+	test_must_fail git -C work push --recurse-submodules=on-demand origin branch2 &&
+	# Fails when refspec includes an object id
+	test_must_fail git -C work push --recurse-submodules=on-demand origin \
+		"$(git -C work rev-parse branch2):refs/heads/branch2" &&
+	# Fails when refspec includes 'HEAD' as it is unsupported at this time
+	test_must_fail git -C work push --recurse-submodules=on-demand origin \
+		HEAD:refs/heads/branch2 &&
+
+	git -C work/gar/bage branch branch2 master &&
+	git -C work push --recurse-submodules=on-demand origin branch2 &&
+
+	git -C submodule.git rev-parse branch2 >actual_submodule &&
+	git -C pub.git rev-parse branch2 >actual_pub &&
+	git -C work/gar/bage rev-parse branch2 >expected_submodule &&
+	git -C work rev-parse branch2 >expected_pub &&
+	test_cmp expected_submodule actual_submodule &&
+	test_cmp expected_pub actual_pub
+'
+
 test_done
diff --git a/t/t5533-push-cas.sh b/t/t5533-push-cas.sh
index a2c9e74..d38ecee 100755
--- a/t/t5533-push-cas.sh
+++ b/t/t5533-push-cas.sh
@@ -229,4 +229,33 @@
 	)
 '
 
+test_expect_success 'background updates of REMOTE can be mitigated with a non-updated REMOTE-push' '
+	rm -rf src dst &&
+	git init --bare src.bare &&
+	test_when_finished "rm -rf src.bare" &&
+	git clone --no-local src.bare dst &&
+	test_when_finished "rm -rf dst" &&
+	(
+		cd dst &&
+		test_commit G &&
+		git remote add origin-push ../src.bare &&
+		git push origin-push master:master
+	) &&
+	git clone --no-local src.bare dst2 &&
+	test_when_finished "rm -rf dst2" &&
+	(
+		cd dst2 &&
+		test_commit H &&
+		git push
+	) &&
+	(
+		cd dst &&
+		test_commit I &&
+		git fetch origin &&
+		test_must_fail git push --force-with-lease origin-push &&
+		git fetch origin-push &&
+		git push --force-with-lease origin-push
+	)
+'
+
 test_done
diff --git a/t/t5545-push-options.sh b/t/t5545-push-options.sh
index 97065e6..f9232f5 100755
--- a/t/t5545-push-options.sh
+++ b/t/t5545-push-options.sh
@@ -142,6 +142,46 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'push options and submodules' '
+	test_when_finished "rm -rf parent" &&
+	test_when_finished "rm -rf parent_upstream" &&
+	mk_repo_pair &&
+	git -C upstream config receive.advertisePushOptions true &&
+	cp -r upstream parent_upstream &&
+	test_commit -C upstream one &&
+
+	test_create_repo parent &&
+	git -C parent remote add up ../parent_upstream &&
+	test_commit -C parent one &&
+	git -C parent push --mirror up &&
+
+	git -C parent submodule add ../upstream workbench &&
+	git -C parent/workbench remote add up ../../upstream &&
+	git -C parent commit -m "add submoule" &&
+
+	test_commit -C parent/workbench two &&
+	git -C parent add workbench &&
+	git -C parent commit -m "update workbench" &&
+
+	git -C parent push \
+		--push-option=asdf --push-option="more structured text" \
+		--recurse-submodules=on-demand up master &&
+
+	git -C upstream rev-parse --verify master >expect &&
+	git -C parent/workbench rev-parse --verify master >actual &&
+	test_cmp expect actual &&
+
+	git -C parent_upstream rev-parse --verify master >expect &&
+	git -C parent rev-parse --verify master >actual &&
+	test_cmp expect actual &&
+
+	printf "asdf\nmore structured text\n" >expect &&
+	test_cmp expect upstream/.git/hooks/pre-receive.push_options &&
+	test_cmp expect upstream/.git/hooks/post-receive.push_options &&
+	test_cmp expect parent_upstream/.git/hooks/pre-receive.push_options &&
+	test_cmp expect parent_upstream/.git/hooks/post-receive.push_options
+'
+
 stop_httpd
 
 test_done
diff --git a/t/t5547-push-quarantine.sh b/t/t5547-push-quarantine.sh
index af9fcd8..113c870 100755
--- a/t/t5547-push-quarantine.sh
+++ b/t/t5547-push-quarantine.sh
@@ -58,4 +58,15 @@
 	git push "$(pwd)/xxx${pathsep}yyy.git" HEAD
 '
 
+test_expect_success 'updating a ref from quarantine is forbidden' '
+	git init --bare update.git &&
+	write_script update.git/hooks/pre-receive <<-\EOF &&
+	read old new refname
+	git update-ref refs/heads/unrelated $new
+	exit 1
+	EOF
+	test_must_fail git push update.git HEAD &&
+	git -C update.git fsck
+'
+
 test_done
diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index b52b8ac..9c56f77 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -427,6 +427,12 @@
 	expect_ssh "-batch -P 123" myhost src
 '
 
+test_expect_success 'clean failure on broken quoting' '
+	test_must_fail \
+		env GIT_SSH_COMMAND="${SQ}plink.exe -v" \
+		git clone "[myhost:123]:src" sq-failure
+'
+
 # Reset the GIT_SSH environment variable for clone tests.
 setup_ssh_wrapper
 
diff --git a/t/t6302-for-each-ref-filter.sh b/t/t6302-for-each-ref-filter.sh
index a09a1a4..fc067ed 100755
--- a/t/t6302-for-each-ref-filter.sh
+++ b/t/t6302-for-each-ref-filter.sh
@@ -93,6 +93,22 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'filtering with --no-contains' '
+	cat >expect <<-\EOF &&
+	refs/tags/one
+	EOF
+	git for-each-ref --format="%(refname)" --no-contains=two >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'filtering with --contains and --no-contains' '
+	cat >expect <<-\EOF &&
+	refs/tags/two
+	EOF
+	git for-each-ref --format="%(refname)" --contains=two --no-contains=three >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success '%(color) must fail' '
 	test_must_fail git for-each-ref --format="%(color)%(refname)"
 '
@@ -421,4 +437,8 @@
 	test_cmp expect actual
 '
 
+test_expect_success '--merged is incompatible with --no-merged' '
+	test_must_fail git for-each-ref --merged HEAD --no-merged HEAD
+'
+
 test_done
diff --git a/t/t6500-gc.sh b/t/t6500-gc.sh
index 08de2e8..cc7acd1 100755
--- a/t/t6500-gc.sh
+++ b/t/t6500-gc.sh
@@ -67,6 +67,16 @@
 	test_line_count = 2 new # There is one new pack and its .idx
 '
 
+run_and_wait_for_auto_gc () {
+	# We read stdout from gc for the side effect of waiting until the
+	# background gc process exits, closing its fd 9.  Furthermore, the
+	# variable assignment from a command substitution preserves the
+	# exit status of the main gc process.
+	# Note: this fd trickery doesn't work on Windows, but there is no
+	# need to, because on Win the auto gc always runs in the foreground.
+	doesnt_matter=$(git gc --auto 9>&1)
+}
+
 test_expect_success 'background auto gc does not run if gc.log is present and recent but does if it is old' '
 	test_commit foo &&
 	test_commit bar &&
@@ -80,7 +90,13 @@
 	test-chmtime =-345600 .git/gc.log &&
 	test_must_fail git gc --auto &&
 	test_config gc.logexpiry 2.days &&
-	git gc --auto
+	run_and_wait_for_auto_gc &&
+	ls .git/objects/pack/pack-*.pack >packs &&
+	test_line_count = 1 packs
 '
 
+# DO NOT leave a detached auto gc process running near the end of the
+# test script: it can run long enough in the background to racily
+# interfere with the cleanup in 'test_done'.
+
 test_done
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index 772dc9e..bb2e4d7 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -16,7 +16,6 @@
 	git show-ref --quiet --verify refs/tags/"$1"
 }
 
-# todo: git tag -l now returns always zero, when fixed, change this test
 test_expect_success 'listing all tags in an empty tree should succeed' '
 	git tag -l &&
 	git tag
@@ -119,6 +118,18 @@
 	git tag
 '
 
+cat >expect <<EOF
+mytag
+EOF
+test_expect_success 'Multiple -l or --list options are equivalent to one -l option' '
+	git tag -l -l >actual &&
+	test_cmp expect actual &&
+	git tag --list --list >actual &&
+	test_cmp expect actual &&
+	git tag --list -l --list >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'listing all tags if one exists should output that tag' '
 	test $(git tag -l) = mytag &&
 	test $(git tag) = mytag
@@ -136,9 +147,8 @@
 	'listing a tag using a matching pattern should output that tag' \
 	'test $(git tag -l mytag) = mytag'
 
-# todo: git tag -l now returns always zero, when fixed, change this test
 test_expect_success \
-	'listing tags using a non-matching pattern should suceed' \
+	'listing tags using a non-matching pattern should succeed' \
 	'git tag -l xxx'
 
 test_expect_success \
@@ -338,6 +348,19 @@
 	test_cmp expect actual
 '
 
+# Between v1.7.7 & v2.13.0 a fair reading of the git-tag documentation
+# could leave you with the impression that "-l <pattern> -l <pattern>"
+# was how we wanted to accept multiple patterns.
+#
+# This test should not imply that this is a sane thing to support. but
+# since the documentation was worded like it was let's at least find
+# out if we're going to break this long-documented form of taking
+# multiple patterns.
+test_expect_success 'tag -l <pattern> -l <pattern> works, as our buggy documentation previously suggested' '
+	git tag -l "v1*" -l "v0*" >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'listing tags in column' '
 	COLUMNS=40 git tag -l --column=row >actual &&
 	cat >expected <<\EOF &&
@@ -620,6 +643,11 @@
 	git tag -n0 -l tag-one-line >actual &&
 	test_cmp expect actual &&
 
+	git tag -n0 | grep "^tag-one-line" >actual &&
+	test_cmp expect actual &&
+	git tag -n0 tag-one-line >actual &&
+	test_cmp expect actual &&
+
 	echo "tag-one-line    A msg" >expect &&
 	git tag -n1 -l | grep "^tag-one-line" >actual &&
 	test_cmp expect actual &&
@@ -633,6 +661,17 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'The -n 100 invocation means -n --list 100, not -n100' '
+	>expect &&
+	git tag -n 100 >actual &&
+	test_cmp expect actual &&
+
+	git tag -m "A msg" 100 &&
+	echo "100             A msg" >expect &&
+	git tag -n 100 >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success \
 	'listing the zero-lines message of a non-signed tag should succeed' '
 	git tag -m "" tag-zero-lines &&
@@ -1383,6 +1422,23 @@
 	test_cmp expected actual
 "
 
+# All the --contains tests above, but with --no-contains
+test_expect_success 'checking that first commit is not listed in any tag with --no-contains  (hash)' "
+	>expected &&
+	git tag -l --no-contains $hash1 v* >actual &&
+	test_cmp expected actual
+"
+
+test_expect_success 'checking that first commit is in all tags (tag)' "
+	git tag -l --no-contains v1.0 v* >actual &&
+	test_cmp expected actual
+"
+
+test_expect_success 'checking that first commit is in all tags (relative)' "
+	git tag -l --no-contains HEAD~2 v* >actual &&
+	test_cmp expected actual
+"
+
 cat > expected <<EOF
 v2.0
 EOF
@@ -1392,6 +1448,17 @@
 	test_cmp expected actual
 "
 
+cat > expected <<EOF
+v0.2.1
+v1.0
+v1.0.1
+v1.1.3
+EOF
+
+test_expect_success 'inverse of the last test, with --no-contains' "
+	git tag -l --no-contains $hash2 v* >actual &&
+	test_cmp expected actual
+"
 
 cat > expected <<EOF
 EOF
@@ -1401,6 +1468,19 @@
 	test_cmp expected actual
 "
 
+cat > expected <<EOF
+v0.2.1
+v1.0
+v1.0.1
+v1.1.3
+v2.0
+EOF
+
+test_expect_success 'conversely --no-contains on the third commit lists all tags' "
+	git tag -l --no-contains $hash3 v* >actual &&
+	test_cmp expected actual
+"
+
 # how about a simple merge?
 
 test_expect_success 'creating simple branch' '
@@ -1422,6 +1502,19 @@
 	test_cmp expected actual
 "
 
+cat > expected <<EOF
+v0.2.1
+v1.0
+v1.0.1
+v1.1.3
+v2.0
+EOF
+
+test_expect_success 'checking that branch head with --no-contains lists all but one tag' "
+	git tag -l --no-contains $hash4 v* >actual &&
+	test_cmp expected actual
+"
+
 test_expect_success 'merging original branch into this branch' '
 	git merge --strategy=ours master &&
         git tag v4.0
@@ -1443,6 +1536,20 @@
 v1.1.3
 v2.0
 v3.0
+EOF
+
+test_expect_success 'checking that original branch head with --no-contains lists all but one tag now' "
+	git tag -l --no-contains $hash3 v* >actual &&
+	test_cmp expected actual
+"
+
+cat > expected <<EOF
+v0.2.1
+v1.0
+v1.0.1
+v1.1.3
+v2.0
+v3.0
 v4.0
 EOF
 
@@ -1451,21 +1558,76 @@
 	test_cmp expected actual
 "
 
+test_expect_success 'checking that --contains can be used in non-list mode' '
+	git tag --contains $hash1 v* >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'checking that initial commit is in all tags with --no-contains' "
+	>expected &&
+	git tag -l --no-contains $hash1 v* >actual &&
+	test_cmp expected actual
+"
+
 # mixing modes and options:
 
 test_expect_success 'mixing incompatibles modes and options is forbidden' '
 	test_must_fail git tag -a &&
+	test_must_fail git tag -a -l &&
+	test_must_fail git tag -s &&
+	test_must_fail git tag -s -l &&
+	test_must_fail git tag -m &&
+	test_must_fail git tag -m -l &&
+	test_must_fail git tag -m "hlagh" &&
+	test_must_fail git tag -m "hlagh" -l &&
+	test_must_fail git tag -F &&
+	test_must_fail git tag -F -l &&
+	test_must_fail git tag -f &&
+	test_must_fail git tag -f -l &&
+	test_must_fail git tag -a -s -m -F &&
+	test_must_fail git tag -a -s -m -F -l &&
 	test_must_fail git tag -l -v &&
-	test_must_fail git tag -n 100 &&
+	test_must_fail git tag -l -d &&
+	test_must_fail git tag -l -v -d &&
+	test_must_fail git tag -n 100 -v &&
 	test_must_fail git tag -l -m msg &&
 	test_must_fail git tag -l -F some file &&
-	test_must_fail git tag -v -s
+	test_must_fail git tag -v -s &&
+	test_must_fail git tag --contains tag-tree &&
+	test_must_fail git tag --contains tag-blob &&
+	test_must_fail git tag --no-contains tag-tree &&
+	test_must_fail git tag --no-contains tag-blob &&
+	test_must_fail git tag --contains --no-contains &&
+	test_must_fail git tag --no-with HEAD &&
+	test_must_fail git tag --no-without HEAD
 '
 
+for option in --contains --with --no-contains --without --merged --no-merged --points-at
+do
+	test_expect_success "mixing incompatible modes with $option is forbidden" "
+		test_must_fail git tag -d $option HEAD &&
+		test_must_fail git tag -d $option HEAD some-tag &&
+		test_must_fail git tag -v $option HEAD
+	"
+	test_expect_success "Doing 'git tag --list-like $option <commit> <pattern> is permitted" "
+		git tag -n $option HEAD HEAD &&
+		git tag $option HEAD HEAD &&
+		git tag $option
+	"
+done
+
 # check points-at
 
-test_expect_success '--points-at cannot be used in non-list mode' '
-	test_must_fail git tag --points-at=v4.0 foo
+test_expect_success '--points-at can be used in non-list mode' '
+	echo v4.0 >expect &&
+	git tag --points-at=v4.0 "v*" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--points-at is a synonym for --points-at HEAD' '
+	echo v4.0 >expect &&
+	git tag --points-at >actual &&
+	test_cmp expect actual
 '
 
 test_expect_success '--points-at finds lightweight tags' '
@@ -1707,7 +1869,7 @@
 test_lazy_prereq ULIMIT_STACK_SIZE 'run_with_limited_stack true'
 
 # we require ulimit, this excludes Windows
-test_expect_success ULIMIT_STACK_SIZE '--contains works in a deep repo' '
+test_expect_success ULIMIT_STACK_SIZE '--contains and --no-contains work in a deep repo' '
 	>expect &&
 	i=1 &&
 	while test $i -lt 8000
@@ -1723,7 +1885,9 @@
 	git checkout master &&
 	git tag far-far-away HEAD^ &&
 	run_with_limited_stack git tag --contains HEAD >actual &&
-	test_cmp expect actual
+	test_cmp expect actual &&
+	run_with_limited_stack git tag --no-contains HEAD >actual &&
+	test_line_count ">" 10 actual
 '
 
 test_expect_success '--format should list tags as per format given' '
@@ -1742,8 +1906,17 @@
 	git tag mergetest-3 HEAD
 '
 
-test_expect_success '--merged cannot be used in non-list mode' '
-	test_must_fail git tag --merged=mergetest-2 foo
+test_expect_success '--merged can be used in non-list mode' '
+	cat >expect <<-\EOF &&
+	mergetest-1
+	mergetest-2
+	EOF
+	git tag --merged=mergetest-2 "mergetest*" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--merged is incompatible with --no-merged' '
+	test_must_fail git tag --merged HEAD --no-merged HEAD
 '
 
 test_expect_success '--merged shows merged tags' '
@@ -1763,6 +1936,11 @@
 	test_cmp expect actual
 '
 
+test_expect_success '--no-merged can be used in non-list mode' '
+	git tag --no-merged=mergetest-2 mergetest-* >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'ambiguous branch/tags not marked' '
 	git tag ambiguous &&
 	git branch ambiguous &&
@@ -1771,4 +1949,47 @@
 	test_cmp expect actual
 '
 
+test_expect_success '--contains combined with --no-contains' '
+	(
+		git init no-contains &&
+		cd no-contains &&
+		test_commit v0.1 &&
+		test_commit v0.2 &&
+		test_commit v0.3 &&
+		test_commit v0.4 &&
+		test_commit v0.5 &&
+		cat >expected <<-\EOF &&
+		v0.2
+		v0.3
+		v0.4
+		EOF
+		git tag --contains v0.2 --no-contains v0.5 >actual &&
+		test_cmp expected actual
+	)
+'
+
+# As the docs say, list tags which contain a specified *commit*. We
+# don't recurse down to tags for trees or blobs pointed to by *those*
+# commits.
+test_expect_success 'Does --[no-]contains stop at commits? Yes!' '
+	cd no-contains &&
+	blob=$(git rev-parse v0.3:v0.3.t) &&
+	tree=$(git rev-parse v0.3^{tree}) &&
+	git tag tag-blob $blob &&
+	git tag tag-tree $tree &&
+	git tag --contains v0.3 >actual &&
+	cat >expected <<-\EOF &&
+	v0.3
+	v0.4
+	v0.5
+	EOF
+	test_cmp expected actual &&
+	git tag --no-contains v0.3 >actual &&
+	cat >expected <<-\EOF &&
+	v0.1
+	v0.2
+	EOF
+	test_cmp expected actual
+'
+
 test_done
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index c09ce0d..1b8f1db 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -38,6 +38,14 @@
 	test_i18ngrep "Submodule path .sub. not initialized" actual
 '
 
+test_expect_success 'submodule update aborts on missing gitmodules url' '
+	test_when_finished "git update-index --remove sub" &&
+	git update-index --add --cacheinfo 160000,$(git rev-parse HEAD),sub &&
+	test_when_finished "rm -f .gitmodules" &&
+	git config -f .gitmodules submodule.s.path sub &&
+	test_must_fail git submodule init
+'
+
 test_expect_success 'configuration parsing' '
 	test_when_finished "rm -f .gitmodules" &&
 	cat >.gitmodules <<-\EOF &&
@@ -273,6 +281,20 @@
 	test_cmp empty untracked
 '
 
+test_expect_success 'submodule add with \\ in path' '
+	test_when_finished "rm -rf parent sub\\with\\backslash" &&
+
+	# Initialize a repo with a backslash in its name
+	git init sub\\with\\backslash &&
+	touch sub\\with\\backslash/empty.file &&
+	git -C sub\\with\\backslash add empty.file &&
+	git -C sub\\with\\backslash commit -m "Added empty.file" &&
+
+	# Add that repository as a submodule
+	git init parent &&
+	git -C parent submodule add ../sub\\with\\backslash
+'
+
 test_expect_success 'submodule add in subdirectory' '
 	echo "refs/heads/master" >expect &&
 	>empty &&
@@ -1130,5 +1152,141 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'setup superproject with submodules' '
+	git init sub1 &&
+	test_commit -C sub1 test &&
+	test_commit -C sub1 test2 &&
+	git init multisuper &&
+	git -C multisuper submodule add ../sub1 sub0 &&
+	git -C multisuper submodule add ../sub1 sub1 &&
+	git -C multisuper submodule add ../sub1 sub2 &&
+	git -C multisuper submodule add ../sub1 sub3 &&
+	git -C multisuper commit -m "add some submodules"
+'
+
+cat >expect <<-EOF
+-sub0
+ sub1 (test2)
+ sub2 (test2)
+ sub3 (test2)
+EOF
+
+test_expect_success 'submodule update --init with a specification' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	pwd=$(pwd) &&
+	git clone file://"$pwd"/multisuper multisuper_clone &&
+	git -C multisuper_clone submodule update --init . ":(exclude)sub0" &&
+	git -C multisuper_clone submodule status |cut -c 1,43- >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'submodule update --init with submodule.active set' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	pwd=$(pwd) &&
+	git clone file://"$pwd"/multisuper multisuper_clone &&
+	git -C multisuper_clone config submodule.active "." &&
+	git -C multisuper_clone config --add submodule.active ":(exclude)sub0" &&
+	git -C multisuper_clone submodule update --init &&
+	git -C multisuper_clone submodule status |cut -c 1,43- >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'submodule update and setting submodule.<name>.active' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	pwd=$(pwd) &&
+	git clone file://"$pwd"/multisuper multisuper_clone &&
+	git -C multisuper_clone config --bool submodule.sub0.active "true" &&
+	git -C multisuper_clone config --bool submodule.sub1.active "false" &&
+	git -C multisuper_clone config --bool submodule.sub2.active "true" &&
+
+	cat >expect <<-\EOF &&
+	 sub0 (test2)
+	-sub1
+	 sub2 (test2)
+	-sub3
+	EOF
+	git -C multisuper_clone submodule update &&
+	git -C multisuper_clone submodule status |cut -c 1,43- >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'clone --recurse-submodules with a pathspec works' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	cat >expected <<-\EOF &&
+	 sub0 (test2)
+	-sub1
+	-sub2
+	-sub3
+	EOF
+
+	git clone --recurse-submodules="sub0" multisuper multisuper_clone &&
+	git -C multisuper_clone submodule status |cut -c1,43- >actual &&
+	test_cmp actual expected
+'
+
+test_expect_success 'clone with multiple --recurse-submodules options' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	cat >expect <<-\EOF &&
+	-sub0
+	 sub1 (test2)
+	-sub2
+	 sub3 (test2)
+	EOF
+
+	git clone --recurse-submodules="." \
+		  --recurse-submodules=":(exclude)sub0" \
+		  --recurse-submodules=":(exclude)sub2" \
+		  multisuper multisuper_clone &&
+	git -C multisuper_clone submodule status |cut -c1,43- >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'clone and subsequent updates correctly auto-initialize submodules' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	cat <<-\EOF >expect &&
+	-sub0
+	 sub1 (test2)
+	-sub2
+	 sub3 (test2)
+	EOF
+
+	cat <<-\EOF >expect2 &&
+	-sub0
+	 sub1 (test2)
+	-sub2
+	 sub3 (test2)
+	-sub4
+	 sub5 (test2)
+	EOF
+
+	git clone --recurse-submodules="." \
+		  --recurse-submodules=":(exclude)sub0" \
+		  --recurse-submodules=":(exclude)sub2" \
+		  --recurse-submodules=":(exclude)sub4" \
+		  multisuper multisuper_clone &&
+
+	git -C multisuper_clone submodule status |cut -c1,43- >actual &&
+	test_cmp expect actual &&
+
+	git -C multisuper submodule add ../sub1 sub4 &&
+	git -C multisuper submodule add ../sub1 sub5 &&
+	git -C multisuper commit -m "add more submodules" &&
+	# obtain the new superproject
+	git -C multisuper_clone pull &&
+	git -C multisuper_clone submodule update --init &&
+	git -C multisuper_clone submodule status |cut -c1,43- >actual &&
+	test_cmp expect2 actual
+'
+
+test_expect_success 'init properly sets the config' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	git clone --recurse-submodules="." \
+		  --recurse-submodules=":(exclude)sub0" \
+		  multisuper multisuper_clone &&
+
+	git -C multisuper_clone submodule init -- sub0 sub1 &&
+	git -C multisuper_clone config --get submodule.sub0.active &&
+	test_must_fail git -C multisuper_clone config --get submodule.sub1.active
+'
 
 test_done
diff --git a/t/t7413-submodule-is-active.sh b/t/t7413-submodule-is-active.sh
new file mode 100755
index 0000000..9c785b0
--- /dev/null
+++ b/t/t7413-submodule-is-active.sh
@@ -0,0 +1,107 @@
+#!/bin/sh
+
+test_description='Test submodule--helper is-active
+
+This test verifies that `git submodue--helper is-active` correclty identifies
+submodules which are "active" and interesting to the user.
+'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	git init sub &&
+	test_commit -C sub initial &&
+	git init super &&
+	test_commit -C super initial &&
+	git -C super submodule add ../sub sub1 &&
+	git -C super submodule add ../sub sub2 &&
+
+	# Remove submodule.<name>.active entries in order to test in an
+	# environment where only URLs are present in the conifg
+	git -C super config --unset submodule.sub1.active &&
+	git -C super config --unset submodule.sub2.active &&
+
+	git -C super commit -a -m "add 2 submodules at sub{1,2}"
+'
+
+test_expect_success 'is-active works with urls' '
+	git -C super submodule--helper is-active sub1 &&
+	git -C super submodule--helper is-active sub2 &&
+
+	git -C super config --unset submodule.sub1.URL &&
+	test_must_fail git -C super submodule--helper is-active sub1 &&
+	git -C super config submodule.sub1.URL ../sub &&
+	git -C super submodule--helper is-active sub1
+'
+
+test_expect_success 'is-active works with submodule.<name>.active config' '
+	test_when_finished "git -C super config --unset submodule.sub1.active" &&
+	test_when_finished "git -C super config submodule.sub1.URL ../sub" &&
+
+	git -C super config --bool submodule.sub1.active "false" &&
+	test_must_fail git -C super submodule--helper is-active sub1 &&
+
+	git -C super config --bool submodule.sub1.active "true" &&
+	git -C super config --unset submodule.sub1.URL &&
+	git -C super submodule--helper is-active sub1
+'
+
+test_expect_success 'is-active works with basic submodule.active config' '
+	test_when_finished "git -C super config submodule.sub1.URL ../sub" &&
+	test_when_finished "git -C super config --unset-all submodule.active" &&
+
+	git -C super config --add submodule.active "." &&
+	git -C super config --unset submodule.sub1.URL &&
+
+	git -C super submodule--helper is-active sub1 &&
+	git -C super submodule--helper is-active sub2
+'
+
+test_expect_success 'is-active correctly works with paths that are not submodules' '
+	test_when_finished "git -C super config --unset-all submodule.active" &&
+
+	test_must_fail git -C super submodule--helper is-active not-a-submodule &&
+
+	git -C super config --add submodule.active "." &&
+	test_must_fail git -C super submodule--helper is-active not-a-submodule
+'
+
+test_expect_success 'is-active works with exclusions in submodule.active config' '
+	test_when_finished "git -C super config --unset-all submodule.active" &&
+
+	git -C super config --add submodule.active "." &&
+	git -C super config --add submodule.active ":(exclude)sub1" &&
+
+	test_must_fail git -C super submodule--helper is-active sub1 &&
+	git -C super submodule--helper is-active sub2
+'
+
+test_expect_success 'is-active with submodule.active and submodule.<name>.active' '
+	test_when_finished "git -C super config --unset-all submodule.active" &&
+	test_when_finished "git -C super config --unset submodule.sub1.active" &&
+	test_when_finished "git -C super config --unset submodule.sub2.active" &&
+
+	git -C super config --add submodule.active "sub1" &&
+	git -C super config --bool submodule.sub1.active "false" &&
+	git -C super config --bool submodule.sub2.active "true" &&
+
+	test_must_fail git -C super submodule--helper is-active sub1 &&
+	git -C super submodule--helper is-active sub2
+'
+
+test_expect_success 'is-active, submodule.active and submodule add' '
+	test_when_finished "rm -rf super2" &&
+	git init super2 &&
+	test_commit -C super2 initial &&
+	git -C super2 config --add submodule.active "sub*" &&
+
+	# submodule add should only add submodule.<name>.active
+	# to the config if not matched by the pathspec
+	git -C super2 submodule add ../sub sub1 &&
+	test_must_fail git -C super2 config --get submodule.sub1.active &&
+
+	git -C super2 submodule add ../sub mod &&
+	git -C super2 config --get submodule.mod.active
+'
+
+test_done
diff --git a/t/t7504-commit-msg-hook.sh b/t/t7504-commit-msg-hook.sh
index 8728db6..88d4cda 100755
--- a/t/t7504-commit-msg-hook.sh
+++ b/t/t7504-commit-msg-hook.sh
@@ -220,4 +220,21 @@
 
 '
 
+# set up fake editor to replace `pick` by `reword`
+cat > reword-editor <<'EOF'
+#!/bin/sh
+mv "$1" "$1".bup &&
+sed 's/^pick/reword/' <"$1".bup >"$1"
+EOF
+chmod +x reword-editor
+REWORD_EDITOR="$(pwd)/reword-editor"
+export REWORD_EDITOR
+
+test_expect_success 'hook is called for reword during `rebase -i`' '
+
+	GIT_SEQUENCE_EDITOR="\"$REWORD_EDITOR\"" git rebase -i HEAD^ &&
+	commit_msg_is "new message"
+
+'
+
 test_done
diff --git a/t/t7506-status-submodule.sh b/t/t7506-status-submodule.sh
index d31b34d..055c907 100755
--- a/t/t7506-status-submodule.sh
+++ b/t/t7506-status-submodule.sh
@@ -17,6 +17,12 @@
 	)
 }
 
+sanitize_output () {
+	sed -e "s/$_x40/HASH/" -e "s/$_x40/HASH/" output >output2 &&
+	mv output2 output
+}
+
+
 test_expect_success 'setup' '
 	test_create_repo_with_commit sub &&
 	echo output > .gitignore &&
@@ -50,6 +56,15 @@
 	EOF
 '
 
+test_expect_success 'status with modified file in submodule (short)' '
+	(cd sub && git reset --hard) &&
+	echo "changed" >sub/foo &&
+	git status --short >output &&
+	diff output - <<-\EOF
+	 m sub
+	EOF
+'
+
 test_expect_success 'status with added file in submodule' '
 	(cd sub && git reset --hard && echo >foo && git add foo) &&
 	git status >output &&
@@ -64,6 +79,14 @@
 	EOF
 '
 
+test_expect_success 'status with added file in submodule (short)' '
+	(cd sub && git reset --hard && echo >foo && git add foo) &&
+	git status --short >output &&
+	diff output - <<-\EOF
+	 m sub
+	EOF
+'
+
 test_expect_success 'status with untracked file in submodule' '
 	(cd sub && git reset --hard) &&
 	echo "content" >sub/new-file &&
@@ -83,6 +106,13 @@
 	EOF
 '
 
+test_expect_success 'status with untracked file in submodule (short)' '
+	git status --short >output &&
+	diff output - <<-\EOF
+	 ? sub
+	EOF
+'
+
 test_expect_success 'status with added and untracked file in submodule' '
 	(cd sub && git reset --hard && echo >foo && git add foo) &&
 	echo "content" >sub/new-file &&
@@ -177,8 +207,24 @@
 	test_i18ngrep "modified:   sub (new commits, modified content)" output
 '
 
+test_expect_success 'status with a lot of untracked files in the submodule' '
+	(
+		cd sub
+		i=0 &&
+		while test $i -lt 1024
+		do
+			>some-file-$i
+			i=$(( $i + 1 ))
+		done
+	) &&
+	git status --porcelain sub 2>err.actual &&
+	test_must_be_empty err.actual &&
+	rm err.actual
+'
+
 test_expect_success 'rm submodule contents' '
-	rm -rf sub/* sub/.git
+	rm -rf sub &&
+	mkdir sub
 '
 
 test_expect_success 'status clean (empty submodule dir)' '
@@ -271,4 +317,91 @@
 	test_cmp diff_submodule_actual diff_submodule_expect
 '
 
+# We'll setup different cases for further testing:
+# sub1 will contain a nested submodule,
+# sub2 will have an untracked file
+# sub3 will have an untracked repository
+test_expect_success 'setup superproject with untracked file in nested submodule' '
+	(
+		cd super &&
+		git clean -dfx &&
+		rm .gitmodules &&
+		git submodule add -f ./sub1 &&
+		git submodule add -f ./sub2 &&
+		git submodule add -f ./sub1 sub3 &&
+		git commit -a -m "messy merge in superproject" &&
+		(
+			cd sub1 &&
+			git submodule add ../sub2 &&
+			git commit -a -m "add sub2 to sub1"
+		) &&
+		git add sub1 &&
+		git commit -a -m "update sub1 to contain nested sub"
+	) &&
+	echo content >super/sub1/sub2/file &&
+	echo content >super/sub2/file &&
+	git -C super/sub3 clone ../../sub2 untracked_repository
+'
+
+test_expect_success 'status with untracked file in nested submodule (porcelain)' '
+	git -C super status --porcelain >output &&
+	diff output - <<-\EOF
+	 M sub1
+	 M sub2
+	 M sub3
+	EOF
+'
+
+test_expect_success 'status with untracked file in nested submodule (porcelain=2)' '
+	git -C super status --porcelain=2 >output &&
+	sanitize_output output &&
+	diff output - <<-\EOF
+	1 .M S..U 160000 160000 160000 HASH HASH sub1
+	1 .M S..U 160000 160000 160000 HASH HASH sub2
+	1 .M S..U 160000 160000 160000 HASH HASH sub3
+	EOF
+'
+
+test_expect_success 'status with untracked file in nested submodule (short)' '
+	git -C super status --short >output &&
+	diff output - <<-\EOF
+	 ? sub1
+	 ? sub2
+	 ? sub3
+	EOF
+'
+
+test_expect_success 'setup superproject with modified file in nested submodule' '
+	git -C super/sub1/sub2 add file &&
+	git -C super/sub2 add file
+'
+
+test_expect_success 'status with added file in nested submodule (porcelain)' '
+	git -C super status --porcelain >output &&
+	diff output - <<-\EOF
+	 M sub1
+	 M sub2
+	 M sub3
+	EOF
+'
+
+test_expect_success 'status with added file in nested submodule (porcelain=2)' '
+	git -C super status --porcelain=2 >output &&
+	sanitize_output output &&
+	diff output - <<-\EOF
+	1 .M S.M. 160000 160000 160000 HASH HASH sub1
+	1 .M S.M. 160000 160000 160000 HASH HASH sub2
+	1 .M S..U 160000 160000 160000 HASH HASH sub3
+	EOF
+'
+
+test_expect_success 'status with added file in nested submodule (short)' '
+	git -C super status --short >output &&
+	diff output - <<-\EOF
+	 m sub1
+	 m sub2
+	 ? sub3
+	EOF
+'
+
 test_done
diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 0e7f30d..7f09867 100755
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -393,6 +393,25 @@
 	git commit -m "modified both"
 '
 
+test_expect_success 'difftool -d with growing paths' '
+	a=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa &&
+	git init growing &&
+	(
+		cd growing &&
+		echo "test -f \"\$2/b\"" | write_script .git/test-for-b.sh &&
+		one=$(printf 1 | git hash-object -w --stdin) &&
+		two=$(printf 2 | git hash-object -w --stdin) &&
+		git update-index --add \
+			--cacheinfo 100644,$one,$a --cacheinfo 100644,$two,b &&
+		tree1=$(git write-tree) &&
+		git update-index --add \
+			--cacheinfo 100644,$two,$a --cacheinfo 100644,$one,b &&
+		tree2=$(git write-tree) &&
+		git checkout -- $a &&
+		git difftool -d --extcmd .git/test-for-b.sh $tree1 $tree2
+	)
+'
+
 run_dir_diff_test () {
 	test_expect_success "$1 --no-symlinks" "
 		symlinks=--no-symlinks &&
diff --git a/t/t7814-grep-recurse-submodules.sh b/t/t7814-grep-recurse-submodules.sh
index 67247a0..5b6eb3a 100755
--- a/t/t7814-grep-recurse-submodules.sh
+++ b/t/t7814-grep-recurse-submodules.sh
@@ -227,6 +227,81 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'grep using relative path' '
+	test_when_finished "rm -rf parent sub" &&
+	git init sub &&
+	echo "foobar" >sub/file &&
+	git -C sub add file &&
+	git -C sub commit -m "add file" &&
+
+	git init parent &&
+	echo "foobar" >parent/file &&
+	git -C parent add file &&
+	mkdir parent/src &&
+	echo "foobar" >parent/src/file2 &&
+	git -C parent add src/file2 &&
+	git -C parent submodule add ../sub &&
+	git -C parent commit -m "add files and submodule" &&
+
+	# From top works
+	cat >expect <<-\EOF &&
+	file:foobar
+	src/file2:foobar
+	sub/file:foobar
+	EOF
+	git -C parent grep --recurse-submodules -e "foobar" >actual &&
+	test_cmp expect actual &&
+
+	# Relative path to top
+	cat >expect <<-\EOF &&
+	../file:foobar
+	file2:foobar
+	../sub/file:foobar
+	EOF
+	git -C parent/src grep --recurse-submodules -e "foobar" -- .. >actual &&
+	test_cmp expect actual &&
+
+	# Relative path to submodule
+	cat >expect <<-\EOF &&
+	../sub/file:foobar
+	EOF
+	git -C parent/src grep --recurse-submodules -e "foobar" -- ../sub >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'grep from a subdir' '
+	test_when_finished "rm -rf parent sub" &&
+	git init sub &&
+	echo "foobar" >sub/file &&
+	git -C sub add file &&
+	git -C sub commit -m "add file" &&
+
+	git init parent &&
+	mkdir parent/src &&
+	echo "foobar" >parent/src/file &&
+	git -C parent add src/file &&
+	git -C parent submodule add ../sub src/sub &&
+	git -C parent submodule add ../sub sub &&
+	git -C parent commit -m "add files and submodules" &&
+
+	# Verify grep from root works
+	cat >expect <<-\EOF &&
+	src/file:foobar
+	src/sub/file:foobar
+	sub/file:foobar
+	EOF
+	git -C parent grep --recurse-submodules -e "foobar" >actual &&
+	test_cmp expect actual &&
+
+	# Verify grep from a subdir works
+	cat >expect <<-\EOF &&
+	file:foobar
+	sub/file:foobar
+	EOF
+	git -C parent/src grep --recurse-submodules -e "foobar" >actual &&
+	test_cmp expect actual
+'
+
 test_incompatible_with_recurse_submodules ()
 {
 	test_expect_success "--recurse-submodules and $1 are incompatible" "
diff --git a/t/t9807-git-p4-submit.sh b/t/t9807-git-p4-submit.sh
index e37239e..3457d5d 100755
--- a/t/t9807-git-p4-submit.sh
+++ b/t/t9807-git-p4-submit.sh
@@ -139,6 +139,22 @@
 	)
 '
 
+test_expect_success 'allow submit from branch with same revision but different name' '
+	test_when_finished cleanup_git &&
+	git p4 clone --dest="$git" //depot &&
+	(
+		cd "$git" &&
+		test_commit "file8" &&
+		git checkout -b branch1 &&
+		git checkout -b branch2 &&
+		git config git-p4.skipSubmitEdit true &&
+		git config git-p4.allowSubmit "branch1" &&
+		test_must_fail git p4 submit &&
+		git checkout branch1 &&
+		git p4 submit
+	)
+'
+
 #
 # Basic submit tests, the five handled cases
 #
diff --git a/t/t9902-completion.sh b/t/t9902-completion.sh
index d711bef..2cb999e 100755
--- a/t/t9902-completion.sh
+++ b/t/t9902-completion.sh
@@ -400,6 +400,22 @@
 	test_cmp expected "$actual"
 '
 
+test_expect_success '__gitcomp_direct - puts everything into COMPREPLY as-is' '
+	sed -e "s/Z$//g" >expected <<-EOF &&
+	with-trailing-space Z
+	without-trailing-spaceZ
+	--option Z
+	--option=Z
+	$invalid_variable_name Z
+	EOF
+	(
+		cur=should_be_ignored &&
+		__gitcomp_direct "$(cat expected)" &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
 test_expect_success '__gitcomp - trailing space - options' '
 	test_gitcomp "--re" "--dry-run --reuse-message= --reedit-message=
 		--reset-author" <<-EOF
@@ -555,6 +571,9 @@
 	cat >expected <<-EOF &&
 	refs/heads/master
 	refs/heads/matching-branch
+	refs/remotes/other/branch-in-other
+	refs/remotes/other/master-in-other
+	refs/tags/matching-tag
 	EOF
 	(
 		cur=refs/heads/ &&
@@ -620,6 +639,7 @@
 
 test_expect_success '__git_refs - configured remote - full refs' '
 	cat >expected <<-EOF &&
+	HEAD
 	refs/heads/branch-in-other
 	refs/heads/master-in-other
 	refs/tags/tag-in-other
@@ -648,6 +668,7 @@
 
 test_expect_success '__git_refs - configured remote - full refs - repo given on the command line' '
 	cat >expected <<-EOF &&
+	HEAD
 	refs/heads/branch-in-other
 	refs/heads/master-in-other
 	refs/tags/tag-in-other
@@ -692,6 +713,7 @@
 
 test_expect_success '__git_refs - URL remote - full refs' '
 	cat >expected <<-EOF &&
+	HEAD
 	refs/heads/branch-in-other
 	refs/heads/master-in-other
 	refs/tags/tag-in-other
@@ -775,6 +797,371 @@
 	test_cmp expected "$actual"
 '
 
+test_expect_success '__git_refs - after --opt=' '
+	cat >expected <<-EOF &&
+	HEAD
+	master
+	matching-branch
+	other/branch-in-other
+	other/master-in-other
+	matching-tag
+	EOF
+	(
+		cur="--opt=" &&
+		__git_refs "" "" "" "" >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success '__git_refs - after --opt= - full refs' '
+	cat >expected <<-EOF &&
+	refs/heads/master
+	refs/heads/matching-branch
+	refs/remotes/other/branch-in-other
+	refs/remotes/other/master-in-other
+	refs/tags/matching-tag
+	EOF
+	(
+		cur="--opt=refs/" &&
+		__git_refs "" "" "" refs/ >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success '__git refs - exluding refs' '
+	cat >expected <<-EOF &&
+	^HEAD
+	^master
+	^matching-branch
+	^other/branch-in-other
+	^other/master-in-other
+	^matching-tag
+	EOF
+	(
+		cur=^ &&
+		__git_refs >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success '__git refs - exluding full refs' '
+	cat >expected <<-EOF &&
+	^refs/heads/master
+	^refs/heads/matching-branch
+	^refs/remotes/other/branch-in-other
+	^refs/remotes/other/master-in-other
+	^refs/tags/matching-tag
+	EOF
+	(
+		cur=^refs/ &&
+		__git_refs >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'setup for filtering matching refs' '
+	git branch matching/branch &&
+	git tag matching/tag &&
+	git -C otherrepo branch matching/branch-in-other &&
+	git fetch --no-tags other &&
+	rm -f .git/FETCH_HEAD
+'
+
+test_expect_success '__git_refs - dont filter refs unless told so' '
+	cat >expected <<-EOF &&
+	HEAD
+	master
+	matching-branch
+	matching/branch
+	other/branch-in-other
+	other/master-in-other
+	other/matching/branch-in-other
+	matching-tag
+	matching/tag
+	EOF
+	(
+		cur=master &&
+		__git_refs >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success '__git_refs - only matching refs' '
+	cat >expected <<-EOF &&
+	matching-branch
+	matching/branch
+	matching-tag
+	matching/tag
+	EOF
+	(
+		cur=mat &&
+		__git_refs "" "" "" "$cur" >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success '__git_refs - only matching refs - full refs' '
+	cat >expected <<-EOF &&
+	refs/heads/matching-branch
+	refs/heads/matching/branch
+	EOF
+	(
+		cur=refs/heads/mat &&
+		__git_refs "" "" "" "$cur" >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success '__git_refs - only matching refs - remote on local file system' '
+	cat >expected <<-EOF &&
+	master-in-other
+	matching/branch-in-other
+	EOF
+	(
+		cur=ma &&
+		__git_refs otherrepo "" "" "$cur" >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success '__git_refs - only matching refs - configured remote' '
+	cat >expected <<-EOF &&
+	master-in-other
+	matching/branch-in-other
+	EOF
+	(
+		cur=ma &&
+		__git_refs other "" "" "$cur" >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success '__git_refs - only matching refs - remote - full refs' '
+	cat >expected <<-EOF &&
+	refs/heads/master-in-other
+	refs/heads/matching/branch-in-other
+	EOF
+	(
+		cur=refs/heads/ma &&
+		__git_refs other "" "" "$cur" >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success '__git_refs - only matching refs - checkout DWIMery' '
+	cat >expected <<-EOF &&
+	matching-branch
+	matching/branch
+	matching-tag
+	matching/tag
+	matching/branch-in-other
+	EOF
+	for remote_ref in refs/remotes/other/ambiguous \
+		refs/remotes/remote/ambiguous \
+		refs/remotes/remote/branch-in-remote
+	do
+		git update-ref $remote_ref master &&
+		test_when_finished "git update-ref -d $remote_ref"
+	done &&
+	(
+		cur=mat &&
+		__git_refs "" 1 "" "$cur" >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success 'teardown after filtering matching refs' '
+	git branch -d matching/branch &&
+	git tag -d matching/tag &&
+	git update-ref -d refs/remotes/other/matching/branch-in-other &&
+	git -C otherrepo branch -D matching/branch-in-other
+'
+
+test_expect_success '__git_refs - for-each-ref format specifiers in prefix' '
+	cat >expected <<-EOF &&
+	evil-%%-%42-%(refname)..master
+	EOF
+	(
+		cur="evil-%%-%42-%(refname)..mas" &&
+		__git_refs "" "" "evil-%%-%42-%(refname).." mas >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
+test_expect_success '__git_complete_refs - simple' '
+	sed -e "s/Z$//" >expected <<-EOF &&
+	HEAD Z
+	master Z
+	matching-branch Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	matching-tag Z
+	EOF
+	(
+		cur= &&
+		__git_complete_refs &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
+test_expect_success '__git_complete_refs - matching' '
+	sed -e "s/Z$//" >expected <<-EOF &&
+	matching-branch Z
+	matching-tag Z
+	EOF
+	(
+		cur=mat &&
+		__git_complete_refs &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
+test_expect_success '__git_complete_refs - remote' '
+	sed -e "s/Z$//" >expected <<-EOF &&
+	HEAD Z
+	branch-in-other Z
+	master-in-other Z
+	EOF
+	(
+		cur=
+		__git_complete_refs --remote=other &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
+test_expect_success '__git_complete_refs - track' '
+	sed -e "s/Z$//" >expected <<-EOF &&
+	HEAD Z
+	master Z
+	matching-branch Z
+	other/branch-in-other Z
+	other/master-in-other Z
+	matching-tag Z
+	branch-in-other Z
+	master-in-other Z
+	EOF
+	(
+		cur=
+		__git_complete_refs --track &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
+test_expect_success '__git_complete_refs - current word' '
+	sed -e "s/Z$//" >expected <<-EOF &&
+	matching-branch Z
+	matching-tag Z
+	EOF
+	(
+		cur="--option=mat" &&
+		__git_complete_refs --cur="${cur#*=}" &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
+test_expect_success '__git_complete_refs - prefix' '
+	sed -e "s/Z$//" >expected <<-EOF &&
+	v1.0..matching-branch Z
+	v1.0..matching-tag Z
+	EOF
+	(
+		cur=v1.0..mat &&
+		__git_complete_refs --pfx=v1.0.. --cur=mat &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
+test_expect_success '__git_complete_refs - suffix' '
+	cat >expected <<-EOF &&
+	HEAD.
+	master.
+	matching-branch.
+	other/branch-in-other.
+	other/master-in-other.
+	matching-tag.
+	EOF
+	(
+		cur= &&
+		__git_complete_refs --sfx=. &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
+test_expect_success '__git_complete_fetch_refspecs - simple' '
+	sed -e "s/Z$//" >expected <<-EOF &&
+	HEAD:HEAD Z
+	branch-in-other:branch-in-other Z
+	master-in-other:master-in-other Z
+	EOF
+	(
+		cur= &&
+		__git_complete_fetch_refspecs other &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
+test_expect_success '__git_complete_fetch_refspecs - matching' '
+	sed -e "s/Z$//" >expected <<-EOF &&
+	branch-in-other:branch-in-other Z
+	EOF
+	(
+		cur=br &&
+		__git_complete_fetch_refspecs other "" br &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
+test_expect_success '__git_complete_fetch_refspecs - prefix' '
+	sed -e "s/Z$//" >expected <<-EOF &&
+	+HEAD:HEAD Z
+	+branch-in-other:branch-in-other Z
+	+master-in-other:master-in-other Z
+	EOF
+	(
+		cur="+" &&
+		__git_complete_fetch_refspecs other "+" ""  &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
+test_expect_success '__git_complete_fetch_refspecs - fully qualified' '
+	sed -e "s/Z$//" >expected <<-EOF &&
+	refs/heads/branch-in-other:refs/heads/branch-in-other Z
+	refs/heads/master-in-other:refs/heads/master-in-other Z
+	refs/tags/tag-in-other:refs/tags/tag-in-other Z
+	EOF
+	(
+		cur=refs/ &&
+		__git_complete_fetch_refspecs other "" refs/ &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
+test_expect_success '__git_complete_fetch_refspecs - fully qualified & prefix' '
+	sed -e "s/Z$//" >expected <<-EOF &&
+	+refs/heads/branch-in-other:refs/heads/branch-in-other Z
+	+refs/heads/master-in-other:refs/heads/master-in-other Z
+	+refs/tags/tag-in-other:refs/tags/tag-in-other Z
+	EOF
+	(
+		cur=+refs/ &&
+		__git_complete_fetch_refspecs other + refs/ &&
+		print_comp
+	) &&
+	test_cmp expected out
+'
+
 test_expect_success 'teardown after ref completion' '
 	git branch -d matching-branch &&
 	git tag -d matching-tag &&
@@ -1070,4 +1457,38 @@
 	test_completion "git add ~/tmp/" "~/tmp/file"
 '
 
+test_expect_success 'setup other remote for remote reference completion' '
+	git remote add other otherrepo &&
+	git fetch other
+'
+
+for flag in -d --delete
+do
+	test_expect_success "__git_complete_remote_or_refspec - push $flag other" '
+		sed -e "s/Z$//" >expected <<-EOF &&
+		master-in-other Z
+		EOF
+		(
+			words=(git push '$flag' other ma) &&
+			cword=${#words[@]} cur=${words[cword-1]} &&
+			__git_complete_remote_or_refspec &&
+			print_comp
+		) &&
+		test_cmp expected out
+	'
+
+	test_expect_failure "__git_complete_remote_or_refspec - push other $flag" '
+		sed -e "s/Z$//" >expected <<-EOF &&
+		master-in-other Z
+		EOF
+		(
+			words=(git push other '$flag' ma) &&
+			cword=${#words[@]} cur=${words[cword-1]} &&
+			__git_complete_remote_or_refspec &&
+			print_comp
+		) &&
+		test_cmp expected out
+	'
+done
+
 test_done
diff --git a/transport-helper.c b/transport-helper.c
index dc90a1f..3640804 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -347,14 +347,11 @@
 static void standard_options(struct transport *t)
 {
 	char buf[16];
-	int n;
 	int v = t->verbose;
 
 	set_helper_option(t, "progress", t->progress ? "true" : "false");
 
-	n = snprintf(buf, sizeof(buf), "%d", v + 1);
-	if (n >= sizeof(buf))
-		die("impossibly large verbosity value");
+	xsnprintf(buf, sizeof(buf), "%d", v + 1);
 	set_helper_option(t, "verbosity", buf);
 
 	switch (t->family) {
diff --git a/transport.c b/transport.c
index 417ed7f..4d33138 100644
--- a/transport.c
+++ b/transport.c
@@ -116,8 +116,8 @@
 	struct child_process *conn;
 	int fd[2];
 	unsigned got_remote_heads : 1;
-	struct sha1_array extra_have;
-	struct sha1_array shallow;
+	struct oid_array extra_have;
+	struct oid_array shallow;
 };
 
 static int set_git_option(struct git_transport_options *opts,
@@ -447,7 +447,7 @@
 
 static int measure_abbrev(const struct object_id *oid, int sofar)
 {
-	char hex[GIT_SHA1_HEXSZ + 1];
+	char hex[GIT_MAX_HEXSZ + 1];
 	int w = find_unique_abbrev_r(hex, oid->hash, DEFAULT_ABBREV);
 
 	return (w < sofar) ? sofar : w;
@@ -1023,19 +1023,22 @@
 			      TRANSPORT_RECURSE_SUBMODULES_ONLY)) &&
 		    !is_bare_repository()) {
 			struct ref *ref = remote_refs;
-			struct sha1_array commits = SHA1_ARRAY_INIT;
+			struct oid_array commits = OID_ARRAY_INIT;
 
 			for (; ref; ref = ref->next)
 				if (!is_null_oid(&ref->new_oid))
-					sha1_array_append(&commits, ref->new_oid.hash);
+					oid_array_append(&commits,
+							  &ref->new_oid);
 
 			if (!push_unpushed_submodules(&commits,
-						      transport->remote->name,
+						      transport->remote,
+						      refspec, refspec_nr,
+						      transport->push_options,
 						      pretend)) {
-				sha1_array_clear(&commits);
+				oid_array_clear(&commits);
 				die("Failed to push all needed submodules!");
 			}
-			sha1_array_clear(&commits);
+			oid_array_clear(&commits);
 		}
 
 		if (((flags & TRANSPORT_RECURSE_SUBMODULES_CHECK) ||
@@ -1044,19 +1047,20 @@
 		      !pretend)) && !is_bare_repository()) {
 			struct ref *ref = remote_refs;
 			struct string_list needs_pushing = STRING_LIST_INIT_DUP;
-			struct sha1_array commits = SHA1_ARRAY_INIT;
+			struct oid_array commits = OID_ARRAY_INIT;
 
 			for (; ref; ref = ref->next)
 				if (!is_null_oid(&ref->new_oid))
-					sha1_array_append(&commits, ref->new_oid.hash);
+					oid_array_append(&commits,
+							  &ref->new_oid);
 
 			if (find_unpushed_submodules(&commits, transport->remote->name,
 						&needs_pushing)) {
-				sha1_array_clear(&commits);
+				oid_array_clear(&commits);
 				die_with_unpushed_submodules(&needs_pushing);
 			}
 			string_list_clear(&needs_pushing, 0);
-			sha1_array_clear(&commits);
+			oid_array_clear(&commits);
 		}
 
 		if (!(flags & TRANSPORT_RECURSE_SUBMODULES_ONLY))
diff --git a/unpack-trees.c b/unpack-trees.c
index 8333da2..aa15111 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -167,7 +167,7 @@
 	msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
 		_("The following working tree files would be removed by sparse checkout update:\n%s");
 	msgs[ERROR_WOULD_LOSE_SUBMODULE] =
-		_("Submodule '%s' cannot checkout new HEAD");
+		_("Cannot update submodule:\n%s");
 
 	opts->show_all_errors = 1;
 	/* rejected paths may not have a static buffer */
@@ -604,12 +604,18 @@
 	return ret;
 }
 
+static inline int are_same_oid(struct name_entry *name_j, struct name_entry *name_k)
+{
+	return name_j->oid && name_k->oid && !oidcmp(name_j->oid, name_k->oid);
+}
+
 static int traverse_trees_recursive(int n, unsigned long dirmask,
 				    unsigned long df_conflicts,
 				    struct name_entry *names,
 				    struct traverse_info *info)
 {
 	int i, ret, bottom;
+	int nr_buf = 0;
 	struct tree_desc t[MAX_UNPACK_TREES];
 	void *buf[MAX_UNPACK_TREES];
 	struct traverse_info newinfo;
@@ -626,18 +632,40 @@
 	newinfo.pathlen += tree_entry_len(p) + 1;
 	newinfo.df_conflicts |= df_conflicts;
 
+	/*
+	 * Fetch the tree from the ODB for each peer directory in the
+	 * n commits.
+	 *
+	 * For 2- and 3-way traversals, we try to avoid hitting the
+	 * ODB twice for the same OID.  This should yield a nice speed
+	 * up in checkouts and merges when the commits are similar.
+	 *
+	 * We don't bother doing the full O(n^2) search for larger n,
+	 * because wider traversals don't happen that often and we
+	 * avoid the search setup.
+	 *
+	 * When 2 peer OIDs are the same, we just copy the tree
+	 * descriptor data.  This implicitly borrows the buffer
+	 * data from the earlier cell.
+	 */
 	for (i = 0; i < n; i++, dirmask >>= 1) {
-		const unsigned char *sha1 = NULL;
-		if (dirmask & 1)
-			sha1 = names[i].oid->hash;
-		buf[i] = fill_tree_descriptor(t+i, sha1);
+		if (i > 0 && are_same_oid(&names[i], &names[i - 1]))
+			t[i] = t[i - 1];
+		else if (i > 1 && are_same_oid(&names[i], &names[i - 2]))
+			t[i] = t[i - 2];
+		else {
+			const unsigned char *sha1 = NULL;
+			if (dirmask & 1)
+				sha1 = names[i].oid->hash;
+			buf[nr_buf++] = fill_tree_descriptor(t+i, sha1);
+		}
 	}
 
 	bottom = switch_cache_bottom(&newinfo);
 	ret = traverse_trees(n, t, &newinfo);
 	restore_cache_bottom(&newinfo, bottom);
 
-	for (i = 0; i < n; i++)
+	for (i = 0; i < nr_buf; i++)
 		free(buf[i]);
 
 	return ret;
diff --git a/wrapper.c b/wrapper.c
index 0542fc7..d837417 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -655,3 +655,16 @@
 {
 	poll(NULL, 0, millisec);
 }
+
+int xgethostname(char *buf, size_t len)
+{
+	/*
+	 * If the full hostname doesn't fit in buf, POSIX does not
+	 * specify whether the buffer will be null-terminated, so to
+	 * be safe, do it ourselves.
+	 */
+	int ret = gethostname(buf, len);
+	if (!ret)
+		buf[len - 1] = 0;
+	return ret;
+}
diff --git a/wt-status.c b/wt-status.c
index 308cf37..0375484 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -407,6 +407,16 @@
 	strbuf_release(&twobuf);
 }
 
+static char short_submodule_status(struct wt_status_change_data *d) {
+	if (d->new_submodule_commits)
+		return 'M';
+	if (d->dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
+		return 'm';
+	if (d->dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
+		return '?';
+	return d->worktree_status;
+}
+
 static void wt_status_collect_changed_cb(struct diff_queue_struct *q,
 					 struct diff_options *options,
 					 void *data)
@@ -431,10 +441,13 @@
 		}
 		if (!d->worktree_status)
 			d->worktree_status = p->status;
-		d->dirty_submodule = p->two->dirty_submodule;
-		if (S_ISGITLINK(p->two->mode))
+		if (S_ISGITLINK(p->two->mode)) {
+			d->dirty_submodule = p->two->dirty_submodule;
 			d->new_submodule_commits = !!oidcmp(&p->one->oid,
 							    &p->two->oid);
+			if (s->status_format == STATUS_FORMAT_SHORT)
+				d->worktree_status = short_submodule_status(d);
+		}
 
 		switch (p->status) {
 		case DIFF_STATUS_ADDED:
diff --git a/wt-status.h b/wt-status.h
index 54fec77..6018c62 100644
--- a/wt-status.h
+++ b/wt-status.h
@@ -80,7 +80,7 @@
 	int hints;
 
 	enum wt_status_format status_format;
-	unsigned char sha1_commit[GIT_SHA1_RAWSZ]; /* when not Initial */
+	unsigned char sha1_commit[GIT_MAX_RAWSZ]; /* when not Initial */
 
 	/* These are computed during processing of the individual sections */
 	int commitable;