Merge branch 'jk/proto-v2-ref-prefix-fix'

"git fetch" over protocol v2 sent an incorrect ref prefix request
to the server and made "git pull" with configured fetch refspec
that does not cover the remote branch to merge with fail, which has
been corrected.

* jk/proto-v2-ref-prefix-fix:
  fetch: add branch.*.merge to default ref-prefix extension
  fetch: stop checking for NULL transport->remote in do_fetch()
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index cd1f526..831f4df 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -309,7 +309,7 @@
     if: needs.ci-config.outputs.enabled == 'yes'
     env:
       jobname: StaticAnalysis
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-22.04
     steps:
     - uses: actions/checkout@v2
     - run: ci/install-dependencies.sh
diff --git a/.gitignore b/.gitignore
index a452215..80b530b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -53,6 +53,7 @@
 /git-cvsimport
 /git-cvsserver
 /git-daemon
+/git-diagnose
 /git-diff
 /git-diff-files
 /git-diff-index
@@ -185,6 +186,7 @@
 /git-worktree
 /git-write-tree
 /git-core-*/?*
+/git.res
 /gitweb/GITWEB-BUILD-OPTIONS
 /gitweb/gitweb.cgi
 /gitweb/static/gitweb.js
@@ -225,7 +227,6 @@
 *.hcc
 *.obj
 *.lib
-*.res
 *.sln
 *.sp
 *.suo
diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines
index 4c756be..9fca21c 100644
--- a/Documentation/CodingGuidelines
+++ b/Documentation/CodingGuidelines
@@ -606,7 +606,7 @@
     avoidance of gendered pronouns.
 
   - When it becomes awkward to stick to this style, prefer "you" when
-    addressing the the hypothetical user, and possibly "we" when
+    addressing the hypothetical user, and possibly "we" when
     discussing how the program might react to the user.  E.g.
 
       You can use this option instead of --xyz, but we might remove
diff --git a/Documentation/Makefile b/Documentation/Makefile
index 4f801f4..849af6d 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -24,10 +24,21 @@
 
 # man5 / man7 guides (note: new guides should also be added to command-list.txt)
 MAN5_TXT += gitattributes.txt
+MAN5_TXT += gitformat-bundle.txt
+MAN5_TXT += gitformat-chunk.txt
+MAN5_TXT += gitformat-commit-graph.txt
+MAN5_TXT += gitformat-index.txt
+MAN5_TXT += gitformat-pack.txt
+MAN5_TXT += gitformat-signature.txt
 MAN5_TXT += githooks.txt
 MAN5_TXT += gitignore.txt
 MAN5_TXT += gitmailmap.txt
 MAN5_TXT += gitmodules.txt
+MAN5_TXT += gitprotocol-capabilities.txt
+MAN5_TXT += gitprotocol-common.txt
+MAN5_TXT += gitprotocol-http.txt
+MAN5_TXT += gitprotocol-pack.txt
+MAN5_TXT += gitprotocol-v2.txt
 MAN5_TXT += gitrepository-layout.txt
 MAN5_TXT += gitweb.conf.txt
 
@@ -51,6 +62,7 @@
 
 DOC_DEP_TXT += $(wildcard *.txt)
 DOC_DEP_TXT += $(wildcard config/*.txt)
+DOC_DEP_TXT += $(wildcard includes/*.txt)
 
 ifdef MAN_FILTER
 MAN_TXT = $(filter $(MAN_FILTER),$(MAN1_TXT) $(MAN5_TXT) $(MAN7_TXT))
@@ -95,26 +107,17 @@
 TECH_DOCS += SubmittingPatches
 TECH_DOCS += ToolsForGit
 TECH_DOCS += technical/bitmap-format
-TECH_DOCS += technical/bundle-format
-TECH_DOCS += technical/cruft-packs
+TECH_DOCS += technical/bundle-uri
 TECH_DOCS += technical/hash-function-transition
-TECH_DOCS += technical/http-protocol
-TECH_DOCS += technical/index-format
 TECH_DOCS += technical/long-running-process-protocol
 TECH_DOCS += technical/multi-pack-index
-TECH_DOCS += technical/pack-format
 TECH_DOCS += technical/pack-heuristics
-TECH_DOCS += technical/pack-protocol
 TECH_DOCS += technical/parallel-checkout
 TECH_DOCS += technical/partial-clone
-TECH_DOCS += technical/protocol-capabilities
-TECH_DOCS += technical/protocol-common
-TECH_DOCS += technical/protocol-v2
 TECH_DOCS += technical/racy-git
 TECH_DOCS += technical/reftable
 TECH_DOCS += technical/send-pack-pipeline
 TECH_DOCS += technical/shallow
-TECH_DOCS += technical/signature-format
 TECH_DOCS += technical/trivial-merge
 SP_ARTICLES += $(TECH_DOCS)
 SP_ARTICLES += technical/api-index
@@ -290,6 +293,8 @@
 	cmds-synchingrepositories.txt \
 	cmds-synchelpers.txt \
 	cmds-guide.txt \
+	cmds-developerinterfaces.txt \
+	cmds-userinterfaces.txt \
 	cmds-purehelpers.txt \
 	cmds-foreignscminterface.txt
 
diff --git a/Documentation/RelNotes/2.37.4.txt b/Documentation/RelNotes/2.37.4.txt
new file mode 100644
index 0000000..7321763
--- /dev/null
+++ b/Documentation/RelNotes/2.37.4.txt
@@ -0,0 +1,31 @@
+Git 2.37.4 Release Notes
+========================
+
+This primarily is to backport various fixes accumulated on the 'master'
+front since 2.37.3.
+
+Fixes since v2.37.3
+-------------------
+
+ * An earlier optimization discarded a tree-object buffer that is
+   still in use, which has been corrected.
+
+ * Fix deadlocks between main Git process and subprocess spawned via
+   the pipe_command() API, that can kill "git add -p" that was
+   reimplemented in C recently.
+
+ * xcalloc(), imitating calloc(), takes "number of elements of the
+   array", and "size of a single element", in this order.  A call that
+   does not follow this ordering has been corrected.
+
+ * The preload-index codepath made copies of pathspec to give to
+   multiple threads, which were left leaked.
+
+ * Update the version of Ubuntu used for GitHub Actions CI from 18.04
+   to 22.04.
+
+ * The auto-stashed local changes created by "git merge --autostash"
+   was mixed into a conflicted state left in the working tree, which
+   has been corrected.
+
+Also contains other minor documentation updates and code clean-ups.
diff --git a/Documentation/RelNotes/2.38.0.txt b/Documentation/RelNotes/2.38.0.txt
new file mode 100644
index 0000000..fe04b31
--- /dev/null
+++ b/Documentation/RelNotes/2.38.0.txt
@@ -0,0 +1,384 @@
+Git v2.38 Release Notes
+=======================
+
+UI, Workflows & Features
+
+ * "git remote show [-n] frotz" now pays attention to negative
+   pathspec.
+
+ * "git push" sometimes perform poorly when reachability bitmaps are
+   used, even in a repository where other operations are helped by
+   bitmaps.  The push.useBitmaps configuration variable is introduced
+   to allow disabling use of reachability bitmaps only for "git push".
+
+ * "git grep -m<max-hits>" is a way to limit the hits shown per file.
+
+ * "git merge-tree" learned a new mode where it takes two commits and
+   computes a tree that would result in the merge commit, if the
+   histories leading to these two commits were to be merged.
+
+ * "git mv A B" in a sparsely populated working tree can be asked to
+   move a path between directories that are "in cone" (i.e. expected
+   to be materialized in the working tree) and "out of cone"
+   (i.e. expected to be hidden).  The handling of such cases has been
+   improved.
+
+ * Earlier, HTTP transport clients learned to tell the server side
+   what locale they are in by sending Accept-Language HTTP header, but
+   this was done only for some requests but not others.
+
+ * Introduce a discovery.barerepository configuration variable that
+   allows users to forbid discovery of bare repositories.
+
+ * Various messages that come from the pack-bitmap codepaths have been
+   tweaked.
+
+ * "git rebase -i" learns to update branches whose tip appear in the
+   rebased range with "--update-refs" option.
+
+ * "git ls-files" learns the "--format" option to tweak its output.
+
+ * "git cat-file" learned an option to use the mailmap when showing
+   commit and tag objects.
+
+ * When "git merge" finds that it cannot perform a merge, it should
+   restore the working tree to the state before the command was
+   initiated, but in some corner cases it didn't.
+
+ * Operating modes like "--batch" of "git cat-file" command learned to
+   take NUL-terminated input, instead of one-item-per-line.
+
+ * "git rm" has become more aware of the sparse-index feature.
+
+ * "git rev-list --disk-usage" learned to take an optional value
+   "human" to show the reported value in human-readable format, like
+   "3.40MiB".
+
+ * The "diagnose" feature to create a zip archive for diagnostic
+   material has been lifted from "scalar" and made into a feature of
+   "git bugreport".
+
+ * The namespaces used by "log --decorate" from "refs/" hierarchy by
+   default has been tightened.
+
+ * "git rev-list --ancestry-path=C A..B" is a natural extension of
+   "git rev-list A..B"; instead of choosing a subset of A..B to those
+   that have ancestry relationship with A, it lets a subset with
+   ancestry relationship with C.
+
+ * "scalar" now enables built-in fsmonitor on enlisted repositories,
+   when able.
+
+ * The bash prompt (in contrib/) learned to optionally indicate when
+   the index is unmerged.
+
+ * "git clone" command learned the "--bundle-uri" option to coordinate
+   with hosting sites the use of pre-prepared bundle files.
+
+ * "git range-diff" learned to honor pathspec argument if given.
+
+ * "git format-patch --from=<ident>" can be told to add an in-body
+   "From:" line even for commits that are authored by the given
+   <ident> with "--force-in-body-from"option.
+
+ * The built-in fsmonitor refuses to work on a network mounted
+   repositories; a configuration knob for users to override this has
+   been introduced.
+
+
+Performance, Internal Implementation, Development Support etc.
+
+ * Collection of what is referenced by objects in promisor packs have
+   been optimized to inspect these objects in the in-pack order.
+
+ * Introduce a helper to see if a branch is already being worked on
+   (hence should not be newly checked out in a working tree), which
+   performs much better than the existing find_shared_symref() to
+   replace many uses of the latter.
+
+ * Teach "git archive" to (optionally and then by default) avoid
+   spawning an external "gzip" process when creating ".tar.gz" (and
+   ".tgz") archives.
+
+ * Allow large objects read from a packstream to be streamed into a
+   loose object file straight, without having to keep it in-core as a
+   whole.
+
+ * Further preparation to turn git-submodule.sh into a builtin
+   continues.
+
+ * Apply Coccinelle rule to turn raw memmove() into MOVE_ARRAY() cpp
+   macro, which would improve maintainability and readability.
+
+ * Teach "make all" to build gitweb as well.
+
+ * Tweak tests so that they still work when the "git init" template
+   did not create .git/info directory.
+
+ * Add Coccinelle rules to detect the pattern of initializing and then
+   finalizing a structure without using it in between at all, which
+   happens after code restructuring and the compilers fail to
+   recognize as an unused variable.
+
+ * The code to convert between GPG trust level strings and internal
+   constants we use to represent them have been cleaned up.
+
+ * Support for libnettle as SHA256 implementation has been added.
+
+ * The way "git multi-pack" uses parse-options API has been improved.
+
+ * A coccinelle rule (in contrib/) to encourage use of COPY_ARRAY
+   macro has been improved.
+
+ * API tweak to make it easier to run fuzz testing on commit-graph parser.
+
+ * Omit fsync-related trace2 entries when their values are all zero.
+
+ * The codepath to write multi-pack index has been taught to release a
+   large chunk of memory that holds an array of objects in the packs,
+   as soon as it is done with the array, to reduce memory consumption.
+
+ * Add a level of redirection to array allocation API in xdiff part,
+   to make it easier to share with the libgit2 project.
+
+ * "git fetch" client logs the partial clone filter used in the trace2
+   output.
+
+ * The "bundle URI" design gets documented.
+
+ * The common ancestor negotiation exchange during a "git fetch"
+   session now leaves trace log.
+
+ * Test portability improvements.
+   (merge 4d1d843be7 mt/rot13-in-c later to maint).
+
+ * The "subcommand" mode is introduced to parse-options API and update
+   the command line parser of Git commands with subcommands.
+
+ * The pack bitmap file gained a bitmap-lookup table to speed up
+   locating the necessary bitmap for a given commit.
+
+ * The assembly version of SHA-1 implementation for PPC has been
+   removed.
+
+ * The server side that responds to "git fetch" and "git clone"
+   request has been optimized by allowing it to send objects in its
+   object store without recomputing and validating the object names.
+
+ * Annotate function parameters that are not used (but cannot be
+   removed for structural reasons), to prepare us to later compile
+   with -Wunused warning turned on.
+
+ * Share the text used to explain configuration variables used by "git
+   <subcmd>" in "git help <subcmd>" with the text from "git help config".
+
+
+Fixes since v2.37
+-----------------
+
+ * Rewrite of "git add -i" in C that appeared in Git 2.25 didn't
+   correctly record a removed file to the index, which was fixed.
+
+ * Certain diff options are currently ignored when combined-diff is
+   shown; mark them as incompatible with the feature.
+
+ * Adjust technical/bitmap-format to be formatted by AsciiDoc, and
+   add some missing information to the documentation.
+
+ * Fixes for tests when the source directory has unusual characters in
+   its path, e.g. whitespaces, double-quotes, etc.
+
+ * "git mktree --missing" lazily fetched objects that are missing from
+   the local object store, which was totally unnecessary for the purpose
+   of creating the tree object(s) from its input.
+
+ * Give _() markings to fatal/warning/usage: labels that are shown in
+   front of these messages.
+
+ * References to commands-to-be-typed-literally in "git rebase"
+   documentation mark-up have been corrected.
+
+ * In a non-bare repository, the behavior of Git when the
+   core.worktree configuration variable points at a directory that has
+   a repository as its subdirectory, regressed in Git 2.27 days.
+
+ * Recent update to vimdiff layout code has been made more robust
+   against different end-user vim settings.
+
+ * Plug various memory leaks, both in the main code and in test-tool
+   commands.
+
+ * Fixes a long-standing corner case bug around directory renames in
+   the merge-ort strategy.
+
+ * The resolve-undo information in the index was not protected against
+   GC, which has been corrected.
+
+ * A corner case bug where lazily fetching objects from a promisor
+   remote resulted in infinite recursion has been corrected.
+
+ * "git clone" from a repository with some ref whose HEAD is unborn
+   did not set the HEAD in the resulting repository correctly, which
+   has been corrected.
+
+ * An earlier attempt to plug leaks placed a clean-up label to jump to
+   at a bogus place, which as been corrected.
+
+ * Variable quoting fix in the vimdiff driver of "git mergetool"
+
+ * "git shortlog -n" relied on the underlying qsort() to be stable,
+   which shouldn't have.  Fixed.
+
+ * A fix for a regression in test framework.
+
+ * mkstemp() emulation on Windows has been improved.
+
+ * Add missing documentation for "include" and "includeIf" features in
+   "git config" file format, which incidentally teaches the command
+   line completion to include them in its offerings.
+
+ * Avoid "white/black-list" in documentation and code comments.
+
+ * Workaround for a compiler warning against use of die() in
+   osx-keychain (in contrib/).
+
+ * Workaround for a false positive compiler warning.
+
+ * "git p4" working on UTF-16 files on Windows did not implement
+   CRLF-to-LF conversion correctly, which has been corrected.
+
+ * "git p4" did not handle non-ASCII client name well, which has been
+   corrected.
+
+ * "rerere-train" script (in contrib/) used to honor commit.gpgSign
+   while recreating the throw-away merges.
+
+ * "git checkout" miscounted the paths it updated, which has been
+   corrected.
+
+ * Fix for a bug that makes write-tree to fail to write out a
+   non-existent index as a tree, introduced in 2.37.
+
+ * There was a bug in the codepath to upgrade generation information
+   in commit-graph from v1 to v2 format, which has been corrected.
+
+ * Gitweb had legacy URL shortener that is specific to the way
+   projects hosted on kernel.org used to (but no longer) work, which
+   has been removed.
+
+ * Fix build procedure for Windows that uses CMake so that it can pick
+   up the shell interpreter from local installation location.
+
+ * Conditionally allow building Python interpreter on Windows
+
+ * Fix to lstat() emulation on Windows.
+
+ * Older gcc with -Wall complains about the universal zero initializer
+   "struct s = { 0 };" idiom, which makes developers' lives
+   inconvenient (as -Werror is enabled by DEVELOPER=YesPlease).  The
+   build procedure has been tweaked to help these compilers.
+
+ * Plug memory leaks in the failure code path in the "merge-ort" merge
+   strategy backend.
+
+ * "git symbolic-ref symref non..sen..se" is now diagnosed as an error.
+
+ * A follow-up fix to a fix for a regression in 2.36 around hooks.
+
+ * Avoid repeatedly running getconf to ask libc version in the test
+   suite, and instead just as it once per script.
+
+ * Platform-specific code that determines if a directory is OK to use
+   as a repository has been taught to report more details, especially
+   on Windows.
+
+ * "vimdiff3" regression fix.
+
+ * "git fsck" reads mode from tree objects but canonicalizes the mode
+   before passing it to the logic to check object sanity, which has
+   hid broken tree objects from the checking logic.  This has been
+   corrected, but to help exiting projects with broken tree objects
+   that they cannot fix retroactively, the severity of anomalies this
+   code detects has been demoted to "info" for now.
+
+ * Fixes to sparse index compatibility work for "reset" and "checkout"
+   commands.
+
+ * An earlier optimization discarded a tree-object buffer that is
+   still in use, which has been corrected.
+   (merge 1490d7d82d jk/is-promisor-object-keep-tree-in-use later to maint).
+
+ * Fix deadlocks between main Git process and subprocess spawned via
+   the pipe_command() API, that can kill "git add -p" that was
+   reimplemented in C recently.
+   (merge 716c1f649e jk/pipe-command-nonblock later to maint).
+
+ * The sequencer machinery translated messages left in the reflog by
+   mistake, which has been corrected.
+
+ * xcalloc(), imitating calloc(), takes "number of elements of the
+   array", and "size of a single element", in this order.  A call that
+   does not follow this ordering has been corrected.
+   (merge c4bbd9bb8f sg/xcalloc-cocci-fix later to maint).
+
+ * The preload-index codepath made copies of pathspec to give to
+   multiple threads, which were left leaked.
+   (merge 23578904da ad/preload-plug-memleak later to maint).
+
+ * Update the version of Ubuntu used for GitHub Actions CI from 18.04
+   to 22.04.
+   (merge ef46584831 ds/github-actions-use-newer-ubuntu later to maint).
+
+ * The auto-stashed local changes created by "git merge --autostash"
+   was mixed into a conflicted state left in the working tree, which
+   has been corrected.
+   (merge d3a9295ada en/merge-unstash-only-on-clean-merge later to maint).
+
+ * Multi-pack index got corrupted when preferred pack changed from one
+   pack to another in a certain way, which has been corrected.
+   (merge 99e4d084ff tb/midx-with-changing-preferred-pack-fix later to maint).
+
+ * The clean-up of temporary files created via mks_tempfile_dt() was
+   racy and attempted to unlink() the leading directory when signals
+   are involved, which has been corrected.
+   (merge babe2e0559 rs/tempfile-cleanup-race-fix later to maint).
+
+ * FreeBSD portability fix for "git maintenance" that spawns "crontab"
+   to schedule tasks.
+   (merge ee69e7884e bc/gc-crontab-fix later to maint).
+
+ * Those who use diff-so-fancy as the diff-filter noticed a regression
+   or two in the code that parses the diff output in the built-in
+   version of "add -p", which has been corrected.
+   (merge 0a101676e5 js/add-p-diff-parsing-fix later to maint).
+
+ * Segfault fix-up to an earlier fix to the topic to teach "git reset"
+   and "git checkout" work better in a sparse checkout.
+   (merge 037f8ea6d9 vd/sparse-reset-checkout-fixes later to maint).
+
+ * "git diff --no-index A B" managed its the pathnames of its two
+   input files rather haphazardly, sometimes leaking them.  The
+   command line argument processing has been straightened out to clean
+   it up.
+   (merge 2b43dd0eb5 rs/diff-no-index-cleanup later to maint).
+
+ * "git rev-list --verify-objects" ought to inspect the contents of
+   objects and notice corrupted ones, but it didn't when the commit
+   graph is in use, which has been corrected.
+   (merge b27ccae34b jk/rev-list-verify-objects-fix later to maint).
+
+ * More fixes to "add -p"
+   (merge 64ec8efb83 js/builtin-add-p-portability-fix later to maint).
+
+ * The parser in the script interface to parse-options in "git
+   rev-parse" has been updated to diagnose a bogus input correctly.
+   (merge f20b9c36d0 ow/rev-parse-parseopt-fix later to maint).
+
+ * The code that manages list-object-filter structure, used in partial
+   clones, leaked the instances, which has been plugged.
+   (merge 66eede4a37 jk/plug-list-object-filter-leaks later to maint).
+
+ * Other code cleanup, docfix, build fix, etc.
+   (merge 77b9e85c0f vd/fix-perf-tests later to maint).
+   (merge 0682bc43f5 jk/test-crontab-fixes later to maint).
+   (merge b46dd1726c cc/doc-trailer-whitespace-rules later to maint).
diff --git a/Documentation/config/core.txt b/Documentation/config/core.txt
index 88bc799c..37afbaf 100644
--- a/Documentation/config/core.txt
+++ b/Documentation/config/core.txt
@@ -444,17 +444,32 @@
 Common unit suffixes of 'k', 'm', or 'g' are supported.
 
 core.bigFileThreshold::
-	Files larger than this size are stored deflated, without
-	attempting delta compression.  Storing large files without
-	delta compression avoids excessive memory usage, at the
-	slight expense of increased disk usage. Additionally files
-	larger than this size are always treated as binary.
+	The size of files considered "big", which as discussed below
+	changes the behavior of numerous git commands, as well as how
+	such files are stored within the repository. The default is
+	512 MiB. Common unit suffixes of 'k', 'm', or 'g' are
+	supported.
 +
-Default is 512 MiB on all platforms.  This should be reasonable
-for most projects as source code and other text files can still
-be delta compressed, but larger binary media files won't be.
+Files above the configured limit will be:
 +
-Common unit suffixes of 'k', 'm', or 'g' are supported.
+* Stored deflated in packfiles, without attempting delta compression.
++
+The default limit is primarily set with this use-case in mind. With it,
+most projects will have their source code and other text files delta
+compressed, but not larger binary media files.
++
+Storing large files without delta compression avoids excessive memory
+usage, at the slight expense of increased disk usage.
++
+* Will be treated as if they were labeled "binary" (see
+  linkgit:gitattributes[5]). e.g. linkgit:git-log[1] and
+  linkgit:git-diff[1] will not compute diffs for files above this limit.
++
+* Will generally be streamed when written, which avoids excessive
+memory usage, at the cost of some fixed overhead. Commands that make
+use of this include linkgit:git-archive[1],
+linkgit:git-fast-import[1], linkgit:git-index-pack[1],
+linkgit:git-unpack-objects[1] and linkgit:git-fsck[1].
 
 core.excludesFile::
 	Specifies the pathname to the file that contains patterns to
diff --git a/Documentation/config/diff.txt b/Documentation/config/diff.txt
index 32f8483..35a7bf8 100644
--- a/Documentation/config/diff.txt
+++ b/Documentation/config/diff.txt
@@ -178,21 +178,6 @@
 	Set this option to true to make the diff driver cache the text
 	conversion outputs.  See linkgit:gitattributes[5] for details.
 
-diff.tool::
-	Controls which diff tool is used by linkgit:git-difftool[1].
-	This variable overrides the value configured in `merge.tool`.
-	The list below shows the valid built-in values.
-	Any other value is treated as a custom diff tool and requires
-	that a corresponding difftool.<tool>.cmd variable is defined.
-
-diff.guitool::
-	Controls which diff tool is used by linkgit:git-difftool[1] when
-	the -g/--gui flag is specified. This variable overrides the value
-	configured in `merge.guitool`. The list below shows the valid
-	built-in values. Any other value is treated as a custom diff tool
-	and requires that a corresponding difftool.<guitool>.cmd variable
-	is defined.
-
 include::../mergetools-diff.txt[]
 
 diff.indentHeuristic::
diff --git a/Documentation/config/difftool.txt b/Documentation/config/difftool.txt
index 6762594..a3f8211 100644
--- a/Documentation/config/difftool.txt
+++ b/Documentation/config/difftool.txt
@@ -1,6 +1,17 @@
-difftool.<tool>.path::
-	Override the path for the given tool.  This is useful in case
-	your tool is not in the PATH.
+diff.tool::
+	Controls which diff tool is used by linkgit:git-difftool[1].
+	This variable overrides the value configured in `merge.tool`.
+	The list below shows the valid built-in values.
+	Any other value is treated as a custom diff tool and requires
+	that a corresponding difftool.<tool>.cmd variable is defined.
+
+diff.guitool::
+	Controls which diff tool is used by linkgit:git-difftool[1] when
+	the -g/--gui flag is specified. This variable overrides the value
+	configured in `merge.guitool`. The list below shows the valid
+	built-in values. Any other value is treated as a custom diff tool
+	and requires that a corresponding difftool.<guitool>.cmd variable
+	is defined.
 
 difftool.<tool>.cmd::
 	Specify the command to invoke the specified diff tool.
@@ -9,6 +20,17 @@
 	file containing the contents of the diff pre-image and 'REMOTE'
 	is set to the name of the temporary file containing the contents
 	of the diff post-image.
++
+See the `--tool=<tool>` option in linkgit:git-difftool[1] for more details.
+
+difftool.<tool>.path::
+	Override the path for the given tool.  This is useful in case
+	your tool is not in the PATH.
+
+difftool.trustExitCode::
+	Exit difftool if the invoked diff tool returns a non-zero exit status.
++
+See the `--trust-exit-code` option in linkgit:git-difftool[1] for more details.
 
 difftool.prompt::
 	Prompt before each invocation of the diff tool.
diff --git a/Documentation/config/format.txt b/Documentation/config/format.txt
index fdbc06a..c7303d8 100644
--- a/Documentation/config/format.txt
+++ b/Documentation/config/format.txt
@@ -15,6 +15,10 @@
 	different.  If set to a non-boolean value, format-patch uses that
 	value instead of your committer identity.  Defaults to false.
 
+format.forceInBodyFrom::
+	Provides the default value for the `--[no-]force-in-body-from`
+	option to format-patch.  Defaults to false.
+
 format.numbered::
 	A boolean which can enable or disable sequence numbers in patch
 	subjects.  It defaults to "auto" which enables it only if there
diff --git a/Documentation/config/grep.txt b/Documentation/config/grep.txt
index 182edd8..e521f20 100644
--- a/Documentation/config/grep.txt
+++ b/Documentation/config/grep.txt
@@ -17,8 +17,11 @@
 	other than 'default'.
 
 grep.threads::
-	Number of grep worker threads to use.
-	See `grep.threads` in linkgit:git-grep[1] for more information.
+	Number of grep worker threads to use. If unset (or set to 0), Git will
+	use as many threads as the number of logical cores available.
+
+grep.fullName::
+	If set to true, enable `--full-name` option by default.
 
 grep.fallbackToNoIndex::
 	If set to true, fall back to git grep --no-index if git grep
diff --git a/Documentation/config/log.txt b/Documentation/config/log.txt
index 456eb07..bc63bc3 100644
--- a/Documentation/config/log.txt
+++ b/Documentation/config/log.txt
@@ -7,6 +7,10 @@
 	Set the default date-time mode for the 'log' command.
 	Setting a value for log.date is similar to using 'git log''s
 	`--date` option.  See linkgit:git-log[1] for details.
++
+If the format is set to "auto:foo" and the pager is in use, format
+"foo" will be the used for the date format. Otherwise "default" will
+be used.
 
 log.decorate::
 	Print out the ref names of any commits that are shown by the log
@@ -18,6 +22,11 @@
 	names are shown. This is the same as the `--decorate` option
 	of the `git log`.
 
+log.initialDecorationSet::
+	By default, `git log` only shows decorations for certain known ref
+	namespaces. If 'all' is specified, then show all refs as
+	decorations.
+
 log.excludeDecoration::
 	Exclude the specified patterns from the log decorations. This is
 	similar to the `--decorate-refs-exclude` command-line option, but
diff --git a/Documentation/config/lsrefs.txt b/Documentation/config/lsrefs.txt
index adeda0f..3d88fb0 100644
--- a/Documentation/config/lsrefs.txt
+++ b/Documentation/config/lsrefs.txt
@@ -1,7 +1,7 @@
 lsrefs.unborn::
 	May be "advertise" (the default), "allow", or "ignore". If "advertise",
 	the server will respond to the client sending "unborn" (as described in
-	protocol-v2.txt) and will advertise support for this feature during the
+	linkgit:gitprotocol-v2[5]) and will advertise support for this feature during the
 	protocol v2 capability advertisement. "allow" is the same as
 	"advertise" except that the server will not advertise support for this
 	feature; this is useful for load-balanced servers that cannot be
diff --git a/Documentation/config/notes.txt b/Documentation/config/notes.txt
index aeef56d..c7c4811 100644
--- a/Documentation/config/notes.txt
+++ b/Documentation/config/notes.txt
@@ -3,6 +3,9 @@
 	conflicts.  Must be one of `manual`, `ours`, `theirs`, `union`, or
 	`cat_sort_uniq`.  Defaults to `manual`.  See "NOTES MERGE STRATEGIES"
 	section of linkgit:git-notes[1] for more information on each strategy.
++
+This setting can be overridden by passing the `--strategy` option to
+linkgit:git-notes[1].
 
 notes.<name>.mergeStrategy::
 	Which merge strategy to choose when doing a notes merge into
@@ -11,28 +14,35 @@
 	linkgit:git-notes[1] for more information on the available strategies.
 
 notes.displayRef::
-	The (fully qualified) refname from which to show notes when
-	showing commit messages.  The value of this variable can be set
-	to a glob, in which case notes from all matching refs will be
-	shown.  You may also specify this configuration variable
-	several times.  A warning will be issued for refs that do not
-	exist, but a glob that does not match any refs is silently
-	ignored.
+	Which ref (or refs, if a glob or specified more than once), in
+	addition to the default set by `core.notesRef` or
+	`GIT_NOTES_REF`, to read notes from when showing commit
+	messages with the 'git log' family of commands.
 +
 This setting can be overridden with the `GIT_NOTES_DISPLAY_REF`
 environment variable, which must be a colon separated list of refs or
 globs.
 +
+A warning will be issued for refs that do not exist,
+but a glob that does not match any refs is silently ignored.
++
+This setting can be disabled by the `--no-notes` option to the 'git
+log' family of commands, or by the `--notes=<ref>` option accepted by
+those commands.
++
 The effective value of "core.notesRef" (possibly overridden by
 GIT_NOTES_REF) is also implicitly added to the list of refs to be
 displayed.
 
 notes.rewrite.<command>::
 	When rewriting commits with <command> (currently `amend` or
-	`rebase`) and this variable is set to `true`, Git
-	automatically copies your notes from the original to the
-	rewritten commit.  Defaults to `true`, but see
-	"notes.rewriteRef" below.
+	`rebase`), if this variable is `false`, git will not copy
+	notes from the original to the rewritten commit.  Defaults to
+	`true`.  See also "`notes.rewriteRef`" below.
++
+This setting can be overridden with the `GIT_NOTES_REWRITE_REF`
+environment variable, which must be a colon separated list of refs or
+globs.
 
 notes.rewriteMode::
 	When copying notes during a rewrite (see the
@@ -46,14 +56,13 @@
 
 notes.rewriteRef::
 	When copying notes during a rewrite, specifies the (fully
-	qualified) ref whose notes should be copied.  The ref may be a
-	glob, in which case notes in all matching refs will be copied.
-	You may also specify this configuration several times.
+	qualified) ref whose notes should be copied.  May be a glob,
+	in which case notes in all matching refs will be copied.  You
+	may also specify this configuration several times.
 +
 Does not have a default value; you must configure this variable to
 enable note rewriting.  Set it to `refs/notes/commits` to enable
 rewriting for the default commit notes.
 +
-This setting can be overridden with the `GIT_NOTES_REWRITE_REF`
-environment variable, which must be a colon separated list of refs or
-globs.
+Can be overridden with the `GIT_NOTES_REWRITE_REF` environment variable.
+See `notes.rewrite.<command>` above for a further description of its format.
diff --git a/Documentation/config/pack.txt b/Documentation/config/pack.txt
index ad7f73a..53093d9 100644
--- a/Documentation/config/pack.txt
+++ b/Documentation/config/pack.txt
@@ -164,9 +164,16 @@
 computed; instead, any namehashes stored in an existing bitmap are
 permuted into their appropriate location when writing a new bitmap.
 
+pack.writeBitmapLookupTable::
+	When true, Git will include a "lookup table" section in the
+	bitmap index (if one is written). This table is used to defer
+	loading individual bitmaps as late as possible. This can be
+	beneficial in repositories that have relatively large bitmap
+	indexes. Defaults to false.
+
 pack.writeReverseIndex::
 	When true, git will write a corresponding .rev file (see:
-	link:../technical/pack-format.html[Documentation/technical/pack-format.txt])
+	linkgit:gitformat-pack[5])
 	for each new packfile that it writes in all places except for
 	linkgit:git-fast-import[1] and in the bulk checkin mechanism.
 	Defaults to false.
diff --git a/Documentation/config/protocol.txt b/Documentation/config/protocol.txt
index 756591d..5760381 100644
--- a/Documentation/config/protocol.txt
+++ b/Documentation/config/protocol.txt
@@ -58,6 +58,6 @@
 * `1` - the original wire protocol with the addition of a version string
   in the initial response from the server.
 
-* `2` - link:technical/protocol-v2.html[wire protocol version 2].
+* `2` - Wire protocol version 2, see linkgit:gitprotocol-v2[5].
 
 --
diff --git a/Documentation/config/push.txt b/Documentation/config/push.txt
index e32801e..7386fea 100644
--- a/Documentation/config/push.txt
+++ b/Documentation/config/push.txt
@@ -137,3 +137,8 @@
 	server attempt to find commits in common. If "false", Git will
 	rely solely on the server's ref advertisement to find commits
 	in common.
+
+push.useBitmaps::
+	If set to "false", disable use of bitmaps for "git push" even if
+	`pack.useBitmaps` is "true", without preventing other git operations
+	from using bitmaps. Default is true.
diff --git a/Documentation/config/rebase.txt b/Documentation/config/rebase.txt
index 8c979cb..f19bd0e 100644
--- a/Documentation/config/rebase.txt
+++ b/Documentation/config/rebase.txt
@@ -21,6 +21,9 @@
 	`--autostash` options of linkgit:git-rebase[1].
 	Defaults to false.
 
+rebase.updateRefs::
+	If set to true enable `--update-refs` option by default.
+
 rebase.missingCommitsCheck::
 	If set to "warn", git rebase -i will print a warning if some
 	commits are removed (e.g. a line was deleted), however the
diff --git a/Documentation/config/safe.txt b/Documentation/config/safe.txt
index fa02f3c..bde7f31 100644
--- a/Documentation/config/safe.txt
+++ b/Documentation/config/safe.txt
@@ -1,3 +1,22 @@
+safe.bareRepository::
+	Specifies which bare repositories Git will work with. The currently
+	supported values are:
++
+* `all`: Git works with all bare repositories. This is the default.
+* `explicit`: Git only works with bare repositories specified via
+  the top-level `--git-dir` command-line option, or the `GIT_DIR`
+  environment variable (see linkgit:git[1]).
++
+If you do not use bare repositories in your workflow, then it may be
+beneficial to set `safe.bareRepository` to `explicit` in your global
+config. This will protect you from attacks that involve cloning a
+repository that contains a bare repository and running a Git command
+within that directory.
++
+This config setting is only respected in protected configuration (see
+<<SCOPES>>). This prevents the untrusted repository from tampering with
+this value.
+
 safe.directory::
 	These config entries specify Git-tracked directories that are
 	considered safe even if they are owned by someone other than the
@@ -12,9 +31,9 @@
 override any such directories specified in the system config), add a
 `safe.directory` entry with an empty value.
 +
-This config setting is only respected when specified in a system or global
-config, not when it is specified in a repository config, via the command
-line option `-c safe.directory=<path>`, or in environment variables.
+This config setting is only respected in protected configuration (see
+<<SCOPES>>). This prevents the untrusted repository from tampering with this
+value.
 +
 The value of this setting is interpolated, i.e. `~/<path>` expands to a
 path relative to the home directory and `%(prefix)/<path>` expands to a
diff --git a/Documentation/config/sendemail.txt b/Documentation/config/sendemail.txt
index 50baa5d..51da708 100644
--- a/Documentation/config/sendemail.txt
+++ b/Documentation/config/sendemail.txt
@@ -18,17 +18,49 @@
 	identity is selected, through either the command-line or
 	`sendemail.identity`.
 
+sendemail.multiEdit::
+	If true (default), a single editor instance will be spawned to edit
+	files you have to edit (patches when `--annotate` is used, and the
+	summary when `--compose` is used). If false, files will be edited one
+	after the other, spawning a new editor each time.
+
+sendemail.confirm::
+	Sets the default for whether to confirm before sending. Must be
+	one of 'always', 'never', 'cc', 'compose', or 'auto'. See `--confirm`
+	in the linkgit:git-send-email[1] documentation for the meaning of these
+	values.
+
 sendemail.aliasesFile::
+	To avoid typing long email addresses, point this to one or more
+	email aliases files.  You must also supply `sendemail.aliasFileType`.
+
 sendemail.aliasFileType::
+	Format of the file(s) specified in sendemail.aliasesFile. Must be
+	one of 'mutt', 'mailrc', 'pine', 'elm', or 'gnus', or 'sendmail'.
++
+What an alias file in each format looks like can be found in
+the documentation of the email program of the same name. The
+differences and limitations from the standard formats are
+described below:
++
+--
+sendmail;;
+*	Quoted aliases and quoted addresses are not supported: lines that
+	contain a `"` symbol are ignored.
+*	Redirection to a file (`/path/name`) or pipe (`|command`) is not
+	supported.
+*	File inclusion (`:include: /path/name`) is not supported.
+*	Warnings are printed on the standard error output for any
+	explicitly unsupported constructs, and any other lines that are not
+	recognized by the parser.
+--
 sendemail.annotate::
 sendemail.bcc::
 sendemail.cc::
 sendemail.ccCmd::
 sendemail.chainReplyTo::
-sendemail.confirm::
 sendemail.envelopeSender::
 sendemail.from::
-sendemail.multiEdit::
 sendemail.signedoffbycc::
 sendemail.smtpPass::
 sendemail.suppresscc::
@@ -44,7 +76,9 @@
 sendemail.transferEncoding::
 sendemail.validate::
 sendemail.xmailer::
-	See linkgit:git-send-email[1] for description.
+	These configuration variables all provide a default for
+	linkgit:git-send-email[1] command-line options. See its
+	documentation for details.
 
 sendemail.signedoffcc (deprecated)::
 	Deprecated alias for `sendemail.signedoffbycc`.
diff --git a/Documentation/config/transfer.txt b/Documentation/config/transfer.txt
index 7ed917f..264812c 100644
--- a/Documentation/config/transfer.txt
+++ b/Documentation/config/transfer.txt
@@ -13,7 +13,7 @@
 You might want to enable this to prevent inadvertent credentials
 exposure, e.g. because:
 +
-* The OS or system where you're running git may not provide way way or
+* The OS or system where you're running git may not provide a way or
   otherwise allow you to configure the permissions of the
   configuration file where the username and/or password are stored.
 * Even if it does, having such data stored "at rest" might expose you
diff --git a/Documentation/config/uploadpack.txt b/Documentation/config/uploadpack.txt
index 32fad5b..16264d8 100644
--- a/Documentation/config/uploadpack.txt
+++ b/Documentation/config/uploadpack.txt
@@ -49,9 +49,9 @@
 	`pack-objects` to the hook, and expects a completed packfile on
 	stdout.
 +
-Note that this configuration variable is ignored if it is seen in the
-repository-level config (this is a safety measure against fetching from
-untrusted repositories).
+Note that this configuration variable is only respected when it is specified
+in protected configuration (see <<SCOPES>>). This is a safety measure
+against fetching from untrusted repositories.
 
 uploadpack.allowFilter::
 	If this option is set, `upload-pack` will support partial
diff --git a/Documentation/git-add.txt b/Documentation/git-add.txt
index 9b37f35..a030d33 100644
--- a/Documentation/git-add.txt
+++ b/Documentation/git-add.txt
@@ -433,6 +433,13 @@
 * deleting context or removal lines
 * modifying the contents of context or removal lines
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/add.txt[]
+
 SEE ALSO
 --------
 linkgit:git-status[1]
diff --git a/Documentation/git-am.txt b/Documentation/git-am.txt
index 09107fb..326276e 100644
--- a/Documentation/git-am.txt
+++ b/Documentation/git-am.txt
@@ -112,10 +112,7 @@
 	am.threeWay configuration variable. For more information,
 	see am.threeWay in linkgit:git-config[1].
 
---rerere-autoupdate::
---no-rerere-autoupdate::
-	Allow the rerere mechanism to update the index with the
-	result of auto-conflict resolution if possible.
+include::rerere-options.txt[]
 
 --ignore-space-change::
 --ignore-whitespace::
@@ -261,6 +258,13 @@
 and `post-applypatch` hooks.  See linkgit:githooks[5] for more
 information.
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/am.txt[]
+
 SEE ALSO
 --------
 linkgit:git-apply[1].
diff --git a/Documentation/git-apply.txt b/Documentation/git-apply.txt
index b6d77f4..1d478cb 100644
--- a/Documentation/git-apply.txt
+++ b/Documentation/git-apply.txt
@@ -263,13 +263,9 @@
 CONFIGURATION
 -------------
 
-apply.ignoreWhitespace::
-	Set to 'change' if you want changes in whitespace to be ignored by default.
-	Set to one of: no, none, never, false if you want changes in
-	whitespace to be significant.
-apply.whitespace::
-	When no `--whitespace` flag is given from the command
-	line, this configuration item is used as the default.
+include::includes/cmd-config-section-all.txt[]
+
+include::config/apply.txt[]
 
 SUBMODULES
 ----------
diff --git a/Documentation/git-archive.txt b/Documentation/git-archive.txt
index 56989a2..60c0409 100644
--- a/Documentation/git-archive.txt
+++ b/Documentation/git-archive.txt
@@ -34,10 +34,12 @@
 -------
 
 --format=<fmt>::
-	Format of the resulting archive: 'tar' or 'zip'. If this option
+	Format of the resulting archive. Possible values are `tar`,
+	`zip`, `tar.gz`, `tgz`, and any format defined using the
+	configuration option `tar.<format>.command`. If `--format`
 	is not given, and the output file is specified, the format is
-	inferred from the filename if possible (e.g. writing to "foo.zip"
-	makes the output to be in the zip format). Otherwise the output
+	inferred from the filename if possible (e.g. writing to `foo.zip`
+	makes the output to be in the `zip` format). Otherwise the output
 	format is `tar`.
 
 -l::
@@ -143,17 +145,16 @@
 	is executed using the shell with the generated tar file on its
 	standard input, and should produce the final output on its
 	standard output. Any compression-level options will be passed
-	to the command (e.g., "-9"). An output file with the same
-	extension as `<format>` will be use this format if no other
-	format is given.
+	to the command (e.g., `-9`).
 +
-The "tar.gz" and "tgz" formats are defined automatically and default to
-`gzip -cn`. You may override them with custom commands.
+The `tar.gz` and `tgz` formats are defined automatically and use the
+magic command `git archive gzip` by default, which invokes an internal
+implementation of gzip.
 
 tar.<format>.remote::
-	If true, enable `<format>` for use by remote clients via
+	If true, enable the format for use by remote clients via
 	linkgit:git-upload-archive[1]. Defaults to false for
-	user-defined formats, but true for the "tar.gz" and "tgz"
+	user-defined formats, but true for the `tar.gz` and `tgz`
 	formats.
 
 [[ATTRIBUTES]]
diff --git a/Documentation/git-blame.txt b/Documentation/git-blame.txt
index d7a46cc..4400a17 100644
--- a/Documentation/git-blame.txt
+++ b/Documentation/git-blame.txt
@@ -241,6 +241,12 @@
 
 See linkgit:gitmailmap[5].
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/blame.txt[]
 
 SEE ALSO
 --------
diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index ae82378..12c5f84 100644
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -336,6 +336,10 @@
 `--list` is used or implied. The default is to use a pager.
 See linkgit:git-config[1].
 
+include::includes/cmd-config-section-rest.txt[]
+
+include::config/branch.txt[]
+
 EXAMPLES
 --------
 
diff --git a/Documentation/git-bugreport.txt b/Documentation/git-bugreport.txt
index d8817bf..eca726e 100644
--- a/Documentation/git-bugreport.txt
+++ b/Documentation/git-bugreport.txt
@@ -9,6 +9,7 @@
 --------
 [verse]
 'git bugreport' [(-o | --output-directory) <path>] [(-s | --suffix) <format>]
+		[--diagnose[=<mode>]]
 
 DESCRIPTION
 -----------
@@ -31,6 +32,10 @@
  - A list of enabled hooks
  - $SHELL
 
+Additional information may be gathered into a separate zip archive using the
+`--diagnose` option, and can be attached alongside the bugreport document to
+provide additional context to readers.
+
 This tool is invoked via the typical Git setup process, which means that in some
 cases, it might not be able to launch - for example, if a relevant config file
 is unreadable. In this kind of scenario, it may be helpful to manually gather
@@ -49,6 +54,19 @@
 	named 'git-bugreport-<formatted suffix>'. This should take the form of a
 	strftime(3) format string; the current local time will be used.
 
+--no-diagnose::
+--diagnose[=<mode>]::
+	Create a zip archive of supplemental information about the user's
+	machine, Git client, and repository state. The archive is written to the
+	same output directory as the bug report and is named
+	'git-diagnostics-<formatted suffix>'.
++
+Without `mode` specified, the diagnostic archive will contain the default set of
+statistics reported by `git diagnose`. An optional `mode` value may be specified
+to change which information is included in the archive. See
+linkgit:git-diagnose[1] for the list of valid values for `mode` and details
+about their usage.
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/git-bundle.txt b/Documentation/git-bundle.txt
index 7685b57..18a022b 100644
--- a/Documentation/git-bundle.txt
+++ b/Documentation/git-bundle.txt
@@ -42,7 +42,7 @@
 Bundles are `.pack` files (see linkgit:git-pack-objects[1]) with a
 header indicating what references are contained within the bundle.
 
-Like the the packed archive format itself bundles can either be
+Like the packed archive format itself bundles can either be
 self-contained, or be created using exclusions.
 See the "OBJECT PREREQUISITES" section below.
 
@@ -56,10 +56,8 @@
 size. That they're "thin" under the hood is merely noted here as a
 curiosity, and as a reference to other documentation.
 
-See link:technical/bundle-format.html[the `bundle-format`
-documentation] for more details and the discussion of "thin pack" in
-link:technical/pack-format.html[the pack format documentation] for
-further details.
+See linkgit:gitformat-bundle[5] for more details and the discussion of
+"thin pack" in linkgit:gitformat-pack[5] for further details.
 
 OPTIONS
 -------
@@ -77,7 +75,7 @@
 	commits exist and are fully linked in the current repository.
 	Then, 'git bundle' prints a list of missing commits, if any.
 	Finally, information about additional capabilities, such as "object
-	filter", is printed. See "Capabilities" in link:technical/bundle-format.html
+	filter", is printed. See "Capabilities" in linkgit:gitformat-bundle[5]
 	for more information. The exit code is zero for success, but will
 	be nonzero if the bundle file is invalid.
 
@@ -337,6 +335,11 @@
 $ git ls-remote mybundle
 ----------------
 
+FILE FORMAT
+-----------
+
+See linkgit:gitformat-bundle[5].
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/git-cat-file.txt b/Documentation/git-cat-file.txt
index 24a811f..ec30b5c 100644
--- a/Documentation/git-cat-file.txt
+++ b/Documentation/git-cat-file.txt
@@ -14,7 +14,7 @@
 'git cat-file' (-t | -s) [--allow-unknown-type] <object>
 'git cat-file' (--batch | --batch-check | --batch-command) [--batch-all-objects]
 	     [--buffer] [--follow-symlinks] [--unordered]
-	     [--textconv | --filters]
+	     [--textconv | --filters] [-z]
 'git cat-file' (--textconv | --filters)
 	     [<rev>:<path|tree-ish> | --path=<path|tree-ish> <rev>]
 
@@ -63,6 +63,12 @@
 	or to ask for a "blob" with `<object>` being a tag object that
 	points at it.
 
+--[no-]mailmap::
+--[no-]use-mailmap::
+       Use mailmap file to map author, committer and tagger names
+       and email addresses to canonical real names and email addresses.
+       See linkgit:git-shortlog[1].
+
 --textconv::
 	Show the content as transformed by a textconv filter. In this case,
 	`<object>` has to be of the form `<tree-ish>:<path>`, or `:<path>` in
@@ -207,6 +213,11 @@
 	/etc/passwd
 --
 
+-z::
+	Only meaningful with `--batch`, `--batch-check`, or
+	`--batch-command`; input is NUL-delimited instead of
+	newline-delimited.
+
 
 OUTPUT
 ------
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index 9f37e22..4cb9d55 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -600,6 +600,13 @@
 $ git add frotz
 ------------
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/checkout.txt[]
+
 SEE ALSO
 --------
 linkgit:git-switch[1],
diff --git a/Documentation/git-cherry-pick.txt b/Documentation/git-cherry-pick.txt
index 78dcc91..1e8ac9d 100644
--- a/Documentation/git-cherry-pick.txt
+++ b/Documentation/git-cherry-pick.txt
@@ -156,10 +156,7 @@
 	Pass the merge strategy-specific option through to the
 	merge strategy.  See linkgit:git-merge[1] for details.
 
---rerere-autoupdate::
---no-rerere-autoupdate::
-	Allow the rerere mechanism to update the index with the
-	result of auto-conflict resolution if possible.
+include::rerere-options.txt[]
 
 SEQUENCER SUBCOMMANDS
 ---------------------
diff --git a/Documentation/git-clean.txt b/Documentation/git-clean.txt
index a7f309d..9174263 100644
--- a/Documentation/git-clean.txt
+++ b/Documentation/git-clean.txt
@@ -133,6 +133,13 @@
 
   Show brief usage of interactive git-clean.
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/clean.txt[]
+
 SEE ALSO
 --------
 linkgit:gitignore[5]
diff --git a/Documentation/git-clone.txt b/Documentation/git-clone.txt
index 632bd13..d6434d2 100644
--- a/Documentation/git-clone.txt
+++ b/Documentation/git-clone.txt
@@ -323,6 +323,13 @@
 	for `host.xz:foo/.git`).  Cloning into an existing directory
 	is only allowed if the directory is empty.
 
+--bundle-uri=<uri>::
+	Before fetching from the remote, fetch a bundle from the given
+	`<uri>` and unbundle the data into the local repository. The refs
+	in the bundle will be stored under the hidden `refs/bundle/*`
+	namespace. This option is incompatible with `--depth`,
+	`--shallow-since`, and `--shallow-exclude`.
+
 :git-clone: 1
 include::urls.txt[]
 
@@ -363,6 +370,15 @@
 $ git clone --bare -l /home/proj/.git /pub/scm/proj.git
 ------------
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/init.txt[]
+
+include::config/clone.txt[]
+
 
 GIT
 ---
diff --git a/Documentation/git-column.txt b/Documentation/git-column.txt
index 6cea9ab..1843164 100644
--- a/Documentation/git-column.txt
+++ b/Documentation/git-column.txt
@@ -74,6 +74,13 @@
 v2.4.8  v2.4.9
 ------------
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/column.txt[]
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt
index e1f48c9..36fe56c 100644
--- a/Documentation/git-commit-graph.txt
+++ b/Documentation/git-commit-graph.txt
@@ -142,6 +142,18 @@
 $ git rev-parse HEAD | git commit-graph write --stdin-commits --append
 ------------------------------------------------
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/commitgraph.txt[]
+
+
+FILE FORMAT
+-----------
+
+see linkgit:gitformat-commit-graph[5].
 
 GIT
 ---
diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt
index 6c60bf9..225c6c9 100644
--- a/Documentation/git-commit.txt
+++ b/Documentation/git-commit.txt
@@ -557,6 +557,10 @@
 `VISUAL` environment variable, or the `EDITOR` environment variable (in that
 order).  See linkgit:git-var[1] for details.
 
+include::includes/cmd-config-section-rest.txt[]
+
+include::config/commit.txt[]
+
 HOOKS
 -----
 This command can run `commit-msg`, `prepare-commit-msg`, `pre-commit`,
diff --git a/Documentation/git-config.txt b/Documentation/git-config.txt
index 9376e39..7a2bcb2 100644
--- a/Documentation/git-config.txt
+++ b/Documentation/git-config.txt
@@ -297,23 +297,20 @@
 FILES
 -----
 
-If not set explicitly with `--file`, there are four files where
-'git config' will search for configuration options:
+By default, 'git config' will read configuration options from multiple
+files:
 
 $(prefix)/etc/gitconfig::
 	System-wide configuration file.
 
 $XDG_CONFIG_HOME/git/config::
-	Second user-specific configuration file. If $XDG_CONFIG_HOME is not set
-	or empty, `$HOME/.config/git/config` will be used. Any single-valued
-	variable set in this file will be overwritten by whatever is in
-	`~/.gitconfig`.  It is a good idea not to create this file if
-	you sometimes use older versions of Git, as support for this
-	file was added fairly recently.
-
 ~/.gitconfig::
-	User-specific configuration file. Also called "global"
-	configuration file.
+	User-specific configuration files. When the XDG_CONFIG_HOME environment
+	variable is not set or empty, $HOME/.config/ is used as
+	$XDG_CONFIG_HOME.
++
+These are also called "global" configuration files. If both files exist, both
+files are read in the order given above.
 
 $GIT_DIR/config::
 	Repository specific configuration file.
@@ -322,28 +319,80 @@
 	This is optional and is only searched when
 	`extensions.worktreeConfig` is present in $GIT_DIR/config.
 
-If no further options are given, all reading options will read all of these
-files that are available. If the global or the system-wide configuration
-file are not available they will be ignored. If the repository configuration
-file is not available or readable, 'git config' will exit with a non-zero
-error code. However, in neither case will an error message be issued.
+You may also provide additional configuration parameters when running any
+git command by using the `-c` option. See linkgit:git[1] for details.
+
+Options will be read from all of these files that are available. If the
+global or the system-wide configuration files are missing or unreadable they
+will be ignored. If the repository configuration file is missing or unreadable,
+'git config' will exit with a non-zero error code. An error message is produced
+if the file is unreadable, but not if it is missing.
 
 The files are read in the order given above, with last value found taking
 precedence over values read earlier.  When multiple values are taken then all
 values of a key from all files will be used.
 
-You may override individual configuration parameters when running any git
-command by using the `-c` option. See linkgit:git[1] for details.
-
-All writing options will per default write to the repository specific
+By default, options are only written to the repository specific
 configuration file. Note that this also affects options like `--replace-all`
 and `--unset`. *'git config' will only ever change one file at a time*.
 
-You can override these rules using the `--global`, `--system`,
-`--local`, `--worktree`, and `--file` command-line options; see
-<<OPTIONS>> above.
+You can limit which configuration sources are read from or written to by
+specifying the path of a file with the `--file` option, or by specifying a
+configuration scope with `--system`, `--global`, `--local`, or `--worktree`.
+For more, see <<OPTIONS>> above.
 
+[[SCOPES]]
+SCOPES
+------
 
+Each configuration source falls within a configuration scope. The scopes
+are:
+
+system::
+	$(prefix)/etc/gitconfig
+
+global::
+	$XDG_CONFIG_HOME/git/config
++
+~/.gitconfig
+
+local::
+	$GIT_DIR/config
+
+worktree::
+	$GIT_DIR/config.worktree
+
+command::
+	GIT_CONFIG_{COUNT,KEY,VALUE} environment variables (see <<ENVIRONMENT>>
+	below)
++
+the `-c` option
+
+With the exception of 'command', each scope corresponds to a command line
+option: `--system`, `--global`, `--local`, `--worktree`.
+
+When reading options, specifying a scope will only read options from the
+files within that scope. When writing options, specifying a scope will write
+to the files within that scope (instead of the repository specific
+configuration file). See <<OPTIONS>> above for a complete description.
+
+Most configuration options are respected regardless of the scope it is
+defined in, but some options are only respected in certain scopes. See the
+respective option's documentation for the full details.
+
+Protected configuration
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Protected configuration refers to the 'system', 'global', and 'command' scopes.
+For security reasons, certain options are only respected when they are
+specified in protected configuration, and ignored otherwise.
+
+Git treats these scopes as if they are controlled by the user or a trusted
+administrator. This is because an attacker who controls these scopes can do
+substantial harm without using Git, so it is assumed that the user's environment
+protects these scopes against attackers.
+
+[[ENVIRONMENT]]
 ENVIRONMENT
 -----------
 
diff --git a/Documentation/git-diagnose.txt b/Documentation/git-diagnose.txt
new file mode 100644
index 0000000..3ec8cc7
--- /dev/null
+++ b/Documentation/git-diagnose.txt
@@ -0,0 +1,65 @@
+git-diagnose(1)
+================
+
+NAME
+----
+git-diagnose - Generate a zip archive of diagnostic information
+
+SYNOPSIS
+--------
+[verse]
+'git diagnose' [(-o | --output-directory) <path>] [(-s | --suffix) <format>]
+	       [--mode=<mode>]
+
+DESCRIPTION
+-----------
+Collects detailed information about the user's machine, Git client, and
+repository state and packages that information into a zip archive. The
+generated archive can then, for example, be shared with the Git mailing list to
+help debug an issue or serve as a reference for independent debugging.
+
+By default, the following information is captured in the archive:
+
+  * 'git version --build-options'
+  * The path to the repository root
+  * The available disk space on the filesystem
+  * The name and size of each packfile, including those in alternate object
+    stores
+  * The total count of loose objects, as well as counts broken down by
+    `.git/objects` subdirectory
+
+Additional information can be collected by selecting a different diagnostic mode
+using the `--mode` option.
+
+This tool differs from linkgit:git-bugreport[1] in that it collects much more
+detailed information with a greater focus on reporting the size and data shape
+of repository contents.
+
+OPTIONS
+-------
+-o <path>::
+--output-directory <path>::
+	Place the resulting diagnostics archive in `<path>` instead of the
+	current directory.
+
+-s <format>::
+--suffix <format>::
+	Specify an alternate suffix for the diagnostics archive name, to create
+	a file named 'git-diagnostics-<formatted suffix>'. This should take the
+	form of a strftime(3) format string; the current local time will be
+	used.
+
+--mode=(stats|all)::
+	Specify the type of diagnostics that should be collected. The default behavior
+	of 'git diagnose' is equivalent to `--mode=stats`.
++
+The `--mode=all` option collects everything included in `--mode=stats`, as well
+as copies of `.git`, `.git/hooks`, `.git/info`, `.git/logs`, and
+`.git/objects/info` directories. This additional information may be sensitive,
+as it can be used to reconstruct the full contents of the diagnosed repository.
+Users should exercise caution when sharing an archive generated with
+`--mode=all`.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/git-diff.txt b/Documentation/git-diff.txt
index 6236c75..85ae6d6 100644
--- a/Documentation/git-diff.txt
+++ b/Documentation/git-diff.txt
@@ -213,6 +213,13 @@
     rewrites (very expensive).
 <2> Output diff in reverse.
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/diff.txt[]
+
 SEE ALSO
 --------
 diff(1),
diff --git a/Documentation/git-difftool.txt b/Documentation/git-difftool.txt
index 143b0c4..9d14c3c 100644
--- a/Documentation/git-difftool.txt
+++ b/Documentation/git-difftool.txt
@@ -113,33 +113,14 @@
 
 See linkgit:git-diff[1] for the full list of supported options.
 
-CONFIG VARIABLES
-----------------
+CONFIGURATION
+-------------
 'git difftool' falls back to 'git mergetool' config variables when the
 difftool equivalents have not been defined.
 
-diff.tool::
-	The default diff tool to use.
+include::includes/cmd-config-section-rest.txt[]
 
-diff.guitool::
-	The default diff tool to use when `--gui` is specified.
-
-difftool.<tool>.path::
-	Override the path for the given tool.  This is useful in case
-	your tool is not in the PATH.
-
-difftool.<tool>.cmd::
-	Specify the command to invoke the specified diff tool.
-+
-See the `--tool=<tool>` option above for more details.
-
-difftool.prompt::
-	Prompt before each invocation of the diff tool.
-
-difftool.trustExitCode::
-	Exit difftool if the invoked diff tool returns a non-zero exit status.
-+
-See the `--trust-exit-code` option above for more details.
+include::config/difftool.txt[]
 
 SEE ALSO
 --------
diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 39cfa05..8b5dd6a 100644
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -1564,6 +1564,13 @@
 import in progress, at the cost of some added running time and worse
 compression.
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/fastimport.txt[]
+
 SEE ALSO
 --------
 linkgit:git-fast-export[1]
diff --git a/Documentation/git-fetch.txt b/Documentation/git-fetch.txt
index e9d3646..63d9569 100644
--- a/Documentation/git-fetch.txt
+++ b/Documentation/git-fetch.txt
@@ -285,6 +285,13 @@
 
 include::transfer-data-leaks.txt[]
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/fetch.txt[]
+
 BUGS
 ----
 Using --recurse-submodules can only fetch new commits in submodules that are
diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index be797d7..dfcc7da 100644
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -275,6 +275,17 @@
 transformation for you, and this option should not be used if you are
 feeding the result to `git send-email`.
 
+--[no-]force-in-body-from::
+	With the e-mail sender specified via the `--from` option, by
+	default, an in-body "From:" to identify the real author of
+	the commit is added at the top of the commit log message if
+	the sender is different from the author.  With this option,
+	the in-body "From:" is added even when the sender and the
+	author have the same name and address, which may help if the
+	mailing list software mangles the sender's identity.
+	Defaults to the value of the `format.forceInBodyFrom`
+	configuration variable.
+
 --add-header=<header>::
 	Add an arbitrary header to the email headers.  This is in addition
 	to any configured headers, and may be used multiple times.
diff --git a/Documentation/git-fsck.txt b/Documentation/git-fsck.txt
index 5088783..29318ea 100644
--- a/Documentation/git-fsck.txt
+++ b/Documentation/git-fsck.txt
@@ -107,6 +107,8 @@
 CONFIGURATION
 -------------
 
+include::includes/cmd-config-section-all.txt[]
+
 include::config/fsck.txt[]
 
 DISCUSSION
diff --git a/Documentation/git-gc.txt b/Documentation/git-gc.txt
index 0af7540..a65c9aa 100644
--- a/Documentation/git-gc.txt
+++ b/Documentation/git-gc.txt
@@ -110,8 +110,7 @@
 CONFIGURATION
 -------------
 
-The below documentation is the same as what's found in
-linkgit:git-config[1]:
+include::includes/cmd-config-section-all.txt[]
 
 include::config/gc.txt[]
 
diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
index 3d393fb..dabdbe8 100644
--- a/Documentation/git-grep.txt
+++ b/Documentation/git-grep.txt
@@ -23,6 +23,7 @@
 	   [--break] [--heading] [-p | --show-function]
 	   [-A <post-context>] [-B <pre-context>] [-C <context>]
 	   [-W | --function-context]
+	   [(-m | --max-count) <num>]
 	   [--threads <num>]
 	   [-f <file>] [-e] <pattern>
 	   [--and|--or|--not|(|)|-e <pattern>...]
@@ -238,6 +239,14 @@
 	`git diff` works out patch hunk headers (see 'Defining a
 	custom hunk-header' in linkgit:gitattributes[5]).
 
+-m <num>::
+--max-count <num>::
+	Limit the amount of matches per file. When using the `-v` or
+	`--invert-match` option, the search stops after the specified
+	number of non-matches. A value of -1 will return unlimited
+	results (the default). A value of 0 will exit immediately with
+	a non-zero status.
+
 --threads <num>::
 	Number of grep worker threads to use.
 	See `grep.threads` in 'CONFIGURATION' for more information.
@@ -334,34 +343,9 @@
 CONFIGURATION
 -------------
 
-grep.lineNumber::
-	If set to true, enable `-n` option by default.
+include::includes/cmd-config-section-all.txt[]
 
-grep.column::
-	If set to true, enable the `--column` option by default.
-
-grep.patternType::
-	Set the default matching behavior. Using a value of 'basic', 'extended',
-	'fixed', or 'perl' will enable the `--basic-regexp`, `--extended-regexp`,
-	`--fixed-strings`, or `--perl-regexp` option accordingly, while the
-	value 'default' will return to the default matching behavior.
-
-grep.extendedRegexp::
-	If set to true, enable `--extended-regexp` option by default. This
-	option is ignored when the `grep.patternType` option is set to a value
-	other than 'default'.
-
-grep.threads::
-	Number of grep worker threads to use. If unset (or set to 0), Git will
-	use as many threads as the number of logical cores available.
-
-grep.fullName::
-	If set to true, enable `--full-name` option by default.
-
-grep.fallbackToNoIndex::
-	If set to true, fall back to git grep --no-index if git grep
-	is executed outside of a git repository.  Defaults to false.
-
+include::config/grep.txt[]
 
 GIT
 ---
diff --git a/Documentation/git-help.txt b/Documentation/git-help.txt
index 239c68d..2b0b5e3 100644
--- a/Documentation/git-help.txt
+++ b/Documentation/git-help.txt
@@ -9,14 +9,16 @@
 --------
 [verse]
 'git help' [-a|--all] [--[no-]verbose] [--[no-]external-commands] [--[no-]aliases]
-'git help' [[-i|--info] [-m|--man] [-w|--web]] [<command>|<guide>]
+'git help' [[-i|--info] [-m|--man] [-w|--web]] [<command>|<doc>]
 'git help' [-g|--guides]
 'git help' [-c|--config]
+'git help' [--user-interfaces]
+'git help' [--developer-interfaces]
 
 DESCRIPTION
 -----------
 
-With no options and no '<command>' or '<guide>' given, the synopsis of the 'git'
+With no options and no '<command>' or '<doc>' given, the synopsis of the 'git'
 command and a list of the most commonly used Git commands are printed
 on the standard output.
 
@@ -26,8 +28,8 @@
 If the option `--guides` or `-g` is given, a list of the
 Git concept guides is also printed on the standard output.
 
-If a command, or a guide, is given, a manual page for that command or
-guide is brought up. The 'man' program is used by default for this
+If a command or other documentation is given, the relevant manual page
+will be brought up. The 'man' program is used by default for this
 purpose, but this can be overridden by other options or configuration
 variables.
 
@@ -69,6 +71,23 @@
 --guides::
 	Prints a list of the Git concept guides on the standard output.
 
+--user-interfaces::
+	Prints a list of the repository, command and file interfaces
+	documentation on the standard output.
++
+In-repository file interfaces such as `.git/info/exclude` are
+documented here (see linkgit:gitrepository-layout[5]), as well as
+in-tree configuration such as `.mailmap` (see linkgit:gitmailmap[5]).
++
+This section of the documentation also covers general or widespread
+user-interface conventions (e.g. linkgit:gitcli[7]), and
+pseudo-configuration such as the file-based `.git/hooks/*` interface
+described in linkgit:githooks[5].
+
+--developer-interfaces::
+	Print list of file formats, protocols and other developer
+	interfaces documentation on the standard output.
+
 -i::
 --info::
 	Display manual page for the command in the 'info' format. The
diff --git a/Documentation/git-imap-send.txt b/Documentation/git-imap-send.txt
index 63cf498..f7b1851 100644
--- a/Documentation/git-imap-send.txt
+++ b/Documentation/git-imap-send.txt
@@ -54,6 +54,8 @@
 To use the tool, `imap.folder` and either `imap.tunnel` or `imap.host` must be set
 to appropriate values.
 
+include::includes/cmd-config-section-rest.txt[]
+
 include::config/imap.txt[]
 
 EXAMPLES
diff --git a/Documentation/git-init.txt b/Documentation/git-init.txt
index ad921fe..160dea1 100644
--- a/Documentation/git-init.txt
+++ b/Documentation/git-init.txt
@@ -169,6 +169,13 @@
 <2> Add all existing files to the index.
 <3> Record the pristine state as the first commit in the history.
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/init.txt[]
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/git-interpret-trailers.txt b/Documentation/git-interpret-trailers.txt
index 956a01d..6d6197c 100644
--- a/Documentation/git-interpret-trailers.txt
+++ b/Documentation/git-interpret-trailers.txt
@@ -60,10 +60,12 @@
 space or the end of the line). Such three minus signs start the patch
 part of the message. See also `--no-divider` below.
 
-When reading trailers, there can be whitespaces after the
-token, the separator and the value. There can also be whitespaces
-inside the token and the value. The value may be split over multiple lines with
-each subsequent line starting with whitespace, like the "folding" in RFC 822.
+When reading trailers, there can be no whitespace before or inside the
+token, but any number of regular space and tab characters are allowed
+between the token and the separator. There can be whitespaces before,
+inside or after the value. The value may be split over multiple lines
+with each subsequent line starting with at least one whitespace, like
+the "folding" in RFC 822.
 
 Note that 'trailers' do not follow and are not intended to follow many
 rules for RFC 822 headers. For example they do not follow
diff --git a/Documentation/git-log.txt b/Documentation/git-log.txt
index 20e87ce..2a66cf8 100644
--- a/Documentation/git-log.txt
+++ b/Documentation/git-log.txt
@@ -45,13 +45,23 @@
 
 --decorate-refs=<pattern>::
 --decorate-refs-exclude=<pattern>::
-	If no `--decorate-refs` is given, pretend as if all refs were
-	included.  For each candidate, do not use it for decoration if it
+	For each candidate reference, do not use it for decoration if it
 	matches any patterns given to `--decorate-refs-exclude` or if it
 	doesn't match any of the patterns given to `--decorate-refs`. The
 	`log.excludeDecoration` config option allows excluding refs from
 	the decorations, but an explicit `--decorate-refs` pattern will
 	override a match in `log.excludeDecoration`.
++
+If none of these options or config settings are given, then references are
+used as decoration if they match `HEAD`, `refs/heads/`, `refs/remotes/`,
+`refs/stash/`, or `refs/tags/`.
+
+--clear-decorations::
+	When specified, this option clears all previous `--decorate-refs`
+	or `--decorate-refs-exclude` options and relaxes the default
+	decoration filter to include all references. This option is
+	assumed if the config value `log.initialDecorationSet` is set to
+	`all`.
 
 --source::
 	Print out the ref name given on the command line by which each
@@ -199,47 +209,11 @@
 	Defaults to the value of `i18n.commitEncoding` if set, and UTF-8
 	otherwise.
 
-log.date::
-	Default format for human-readable dates.  (Compare the
-	`--date` option.)  Defaults to "default", which means to write
-	dates like `Sat May 8 19:35:34 2010 -0500`.
-+
-If the format is set to "auto:foo" and the pager is in use, format
-"foo" will be the used for the date format. Otherwise "default" will
-be used.
+include::includes/cmd-config-section-rest.txt[]
 
-log.follow::
-	If `true`, `git log` will act as if the `--follow` option was used when
-	a single <path> is given.  This has the same limitations as `--follow`,
-	i.e. it cannot be used to follow multiple files and does not work well
-	on non-linear history.
+include::config/log.txt[]
 
-log.showRoot::
-	If `false`, `git log` and related commands will not treat the
-	initial commit as a big creation event.  Any root commits in
-	`git log -p` output would be shown without a diff attached.
-	The default is `true`.
-
-log.showSignature::
-	If `true`, `git log` and related commands will act as if the
-	`--show-signature` option was passed to them.
-
-mailmap.*::
-	See linkgit:git-shortlog[1].
-
-notes.displayRef::
-	Which refs, in addition to the default set by `core.notesRef`
-	or `GIT_NOTES_REF`, to read notes from when showing commit
-	messages with the `log` family of commands.  See
-	linkgit:git-notes[1].
-+
-May be an unabbreviated ref name or a glob and may be specified
-multiple times.  A warning will be issued for refs that do not exist,
-but a glob that does not match any refs is silently ignored.
-+
-This setting can be disabled by the `--no-notes` option,
-overridden by the `GIT_NOTES_DISPLAY_REF` environment variable,
-and overridden by the `--notes=<ref>` option.
+include::config/notes.txt[]
 
 GIT
 ---
diff --git a/Documentation/git-ls-files.txt b/Documentation/git-ls-files.txt
index 0dabf3f..d798641 100644
--- a/Documentation/git-ls-files.txt
+++ b/Documentation/git-ls-files.txt
@@ -20,7 +20,7 @@
 		[--exclude-standard]
 		[--error-unmatch] [--with-tree=<tree-ish>]
 		[--full-name] [--recurse-submodules]
-		[--abbrev[=<n>]] [--] [<file>...]
+		[--abbrev[=<n>]] [--format=<format>] [--] [<file>...]
 
 DESCRIPTION
 -----------
@@ -192,6 +192,13 @@
 	to the contained files. Sparse directories will be shown with a
 	trailing slash, such as "x/" for a sparse directory "x".
 
+--format=<format>::
+	A string that interpolates `%(fieldname)` from the result being shown.
+	It also interpolates `%%` to `%`, and `%xx` where `xx` are hex digits
+	interpolates to character with hex code `xx`; for example `%00`
+	interpolates to `\0` (NUL), `%09` to `\t` (TAB) and %0a to `\n` (LF).
+	--format cannot be combined with `-s`, `-o`, `-k`, `-t`, `--resolve-undo`
+	and `--eol`.
 \--::
 	Do not interpret any more arguments as options.
 
@@ -223,6 +230,36 @@
 (see linkgit:git-config[1]).  Using `-z` the filename is output
 verbatim and the line is terminated by a NUL byte.
 
+It is possible to print in a custom format by using the `--format`
+option, which is able to interpolate different fields using
+a `%(fieldname)` notation. For example, if you only care about the
+"objectname" and "path" fields, you can execute with a specific
+"--format" like
+
+	git ls-files --format='%(objectname) %(path)'
+
+FIELD NAMES
+-----------
+The way each path is shown can be customized by using the
+`--format=<format>` option, where the %(fieldname) in the
+<format> string for various aspects of the index entry are
+interpolated.  The following "fieldname" are understood:
+
+objectmode::
+	The mode of the file which is recorded in the index.
+objectname::
+	The name of the file which is recorded in the index.
+stage::
+	The stage of the file which is recorded in the index.
+eolinfo:index::
+eolinfo:worktree::
+	The <eolinfo> (see the description of the `--eol` option) of
+	the contents in the index or in the worktree for the path.
+eolattr::
+	The <eolattr> (see the description of the `--eol` option)
+	that applies to the path.
+path::
+	The pathname of the file which is recorded in the index.
 
 EXCLUDE PATTERNS
 ----------------
diff --git a/Documentation/git-mailinfo.txt b/Documentation/git-mailinfo.txt
index 3fcfd96..2806028 100644
--- a/Documentation/git-mailinfo.txt
+++ b/Documentation/git-mailinfo.txt
@@ -115,6 +115,13 @@
 <patch>::
 	The patch extracted from e-mail.
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/mailinfo.txt[]
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/git-maintenance.txt b/Documentation/git-maintenance.txt
index e56bad2..9c630ef 100644
--- a/Documentation/git-maintenance.txt
+++ b/Documentation/git-maintenance.txt
@@ -397,6 +397,13 @@
 so future calls to `git maintenance (start|stop)` do not overwrite your
 custom tasks.
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/maintenance.txt[]
+
 
 GIT
 ---
diff --git a/Documentation/git-merge-tree.txt b/Documentation/git-merge-tree.txt
index 58731c1..d6c3567 100644
--- a/Documentation/git-merge-tree.txt
+++ b/Documentation/git-merge-tree.txt
@@ -3,26 +3,237 @@
 
 NAME
 ----
-git-merge-tree - Show three-way merge without touching index
+git-merge-tree - Perform merge without touching index or working tree
 
 
 SYNOPSIS
 --------
 [verse]
-'git merge-tree' <base-tree> <branch1> <branch2>
+'git merge-tree' [--write-tree] [<options>] <branch1> <branch2>
+'git merge-tree' [--trivial-merge] <base-tree> <branch1> <branch2> (deprecated)
 
+[[NEWMERGE]]
 DESCRIPTION
 -----------
-Reads three tree-ish, and output trivial merge results and
-conflicting stages to the standard output.  This is similar to
-what three-way 'git read-tree -m' does, but instead of storing the
-results in the index, the command outputs the entries to the
-standard output.
 
-This is meant to be used by higher level scripts to compute
-merge results outside of the index, and stuff the results back into the
-index.  For this reason, the output from the command omits
-entries that match the <branch1> tree.
+This command has a modern `--write-tree` mode and a deprecated
+`--trivial-merge` mode.  With the exception of the
+<<DEPMERGE,DEPRECATED DESCRIPTION>> section at the end, the rest of
+this documentation describes modern `--write-tree` mode.
+
+Performs a merge, but does not make any new commits and does not read
+from or write to either the working tree or index.
+
+The performed merge will use the same feature as the "real"
+linkgit:git-merge[1], including:
+
+  * three way content merges of individual files
+  * rename detection
+  * proper directory/file conflict handling
+  * recursive ancestor consolidation (i.e. when there is more than one
+    merge base, creating a virtual merge base by merging the merge bases)
+  * etc.
+
+After the merge completes, a new toplevel tree object is created.  See
+`OUTPUT` below for details.
+
+OPTIONS
+-------
+
+-z::
+	Do not quote filenames in the <Conflicted file info> section,
+	and end each filename with a NUL character rather than
+	newline.  Also begin the messages section with a NUL character
+	instead of a newline.  See <<OUTPUT>> below for more information.
+
+--name-only::
+	In the Conflicted file info section, instead of writing a list
+	of (mode, oid, stage, path) tuples to output for conflicted
+	files, just provide a list of filenames with conflicts (and
+	do not list filenames multiple times if they have multiple
+	conflicting stages).
+
+--[no-]messages::
+	Write any informational messages such as "Auto-merging <path>"
+	or CONFLICT notices to the end of stdout.  If unspecified, the
+	default is to include these messages if there are merge
+	conflicts, and to omit them otherwise.
+
+--allow-unrelated-histories::
+	merge-tree will by default error out if the two branches specified
+	share no common history.  This flag can be given to override that
+	check and make the merge proceed anyway.
+
+[[OUTPUT]]
+OUTPUT
+------
+
+For a successful merge, the output from git-merge-tree is simply one
+line:
+
+	<OID of toplevel tree>
+
+Whereas for a conflicted merge, the output is by default of the form:
+
+	<OID of toplevel tree>
+	<Conflicted file info>
+	<Informational messages>
+
+These are discussed individually below.
+
+[[OIDTLT]]
+OID of toplevel tree
+~~~~~~~~~~~~~~~~~~~~
+
+This is a tree object that represents what would be checked out in the
+working tree at the end of `git merge`.  If there were conflicts, then
+files within this tree may have embedded conflict markers.  This section
+is always followed by a newline (or NUL if `-z` is passed).
+
+[[CFI]]
+Conflicted file info
+~~~~~~~~~~~~~~~~~~~~
+
+This is a sequence of lines with the format
+
+	<mode> <object> <stage> <filename>
+
+The filename will be quoted as explained for the configuration
+variable `core.quotePath` (see linkgit:git-config[1]).  However, if
+the `--name-only` option is passed, the mode, object, and stage will
+be omitted.  If `-z` is passed, the "lines" are terminated by a NUL
+character instead of a newline character.
+
+[[IM]]
+Informational messages
+~~~~~~~~~~~~~~~~~~~~~~
+
+This always starts with a blank line (or NUL if `-z` is passed) to
+separate it from the previous sections, and then has free-form
+messages about the merge, such as:
+
+  * "Auto-merging <file>"
+  * "CONFLICT (rename/delete): <oldfile> renamed...but deleted in..."
+  * "Failed to merge submodule <submodule> (<reason>)"
+  * "Warning: cannot merge binary files: <filename>"
+
+Note that these free-form messages will never have a NUL character
+in or between them, even if -z is passed.  It is simply a large block
+of text taking up the remainder of the output.
+
+EXIT STATUS
+-----------
+
+For a successful, non-conflicted merge, the exit status is 0.  When the
+merge has conflicts, the exit status is 1.  If the merge is not able to
+complete (or start) due to some kind of error, the exit status is
+something other than 0 or 1 (and the output is unspecified).
+
+USAGE NOTES
+-----------
+
+This command is intended as low-level plumbing, similar to
+linkgit:git-hash-object[1], linkgit:git-mktree[1],
+linkgit:git-commit-tree[1], linkgit:git-write-tree[1],
+linkgit:git-update-ref[1], and linkgit:git-mktag[1].  Thus, it can be
+used as a part of a series of steps such as:
+
+       NEWTREE=$(git merge-tree --write-tree $BRANCH1 $BRANCH2)
+       test $? -eq 0 || die "There were conflicts..."
+       NEWCOMMIT=$(git commit-tree $NEWTREE -p $BRANCH1 -p $BRANCH2)
+       git update-ref $BRANCH1 $NEWCOMMIT
+
+Note that when the exit status is non-zero, `NEWTREE` in this sequence
+will contain a lot more output than just a tree.
+
+For conflicts, the output includes the same information that you'd get
+with linkgit:git-merge[1]:
+
+  * what would be written to the working tree (the
+    <<OIDTLT,OID of toplevel tree>>)
+  * the higher order stages that would be written to the index (the
+    <<CFI,Conflicted file info>>)
+  * any messages that would have been printed to stdout (the
+    <<IM,Informational messages>>)
+
+MISTAKES TO AVOID
+-----------------
+
+Do NOT look through the resulting toplevel tree to try to find which
+files conflict; parse the <<CFI,Conflicted file info>> section instead.
+Not only would parsing an entire tree be horrendously slow in large
+repositories, there are numerous types of conflicts not representable by
+conflict markers (modify/delete, mode conflict, binary file changed on
+both sides, file/directory conflicts, various rename conflict
+permutations, etc.)
+
+Do NOT interpret an empty <<CFI,Conflicted file info>> list as a clean
+merge; check the exit status.  A merge can have conflicts without having
+individual files conflict (there are a few types of directory rename
+conflicts that fall into this category, and others might also be added
+in the future).
+
+Do NOT attempt to guess or make the user guess the conflict types from
+the <<CFI,Conflicted file info>> list.  The information there is
+insufficient to do so.  For example: Rename/rename(1to2) conflicts (both
+sides renamed the same file differently) will result in three different
+file having higher order stages (but each only has one higher order
+stage), with no way (short of the <<IM,Informational messages>> section)
+to determine which three files are related.  File/directory conflicts
+also result in a file with exactly one higher order stage.
+Possibly-involved-in-directory-rename conflicts (when
+"merge.directoryRenames" is unset or set to "conflicts") also result in
+a file with exactly one higher order stage.  In all cases, the
+<<IM,Informational messages>> section has the necessary info, though it
+is not designed to be machine parseable.
+
+Do NOT assume that each paths from <<CFI,Conflicted file info>>, and
+the logical conflicts in the <<IM,Informational messages>> have a
+one-to-one mapping, nor that there is a one-to-many mapping, nor a
+many-to-one mapping.  Many-to-many mappings exist, meaning that each
+path can have many logical conflict types in a single merge, and each
+logical conflict type can affect many paths.
+
+Do NOT assume all filenames listed in the <<IM,Informational messages>>
+section had conflicts.  Messages can be included for files that have no
+conflicts, such as "Auto-merging <file>".
+
+AVOID taking the OIDS from the <<CFI,Conflicted file info>> and
+re-merging them to present the conflicts to the user.  This will lose
+information.  Instead, look up the version of the file found within the
+<<OIDTLT,OID of toplevel tree>> and show that instead.  In particular,
+the latter will have conflict markers annotated with the original
+branch/commit being merged and, if renames were involved, the original
+filename.  While you could include the original branch/commit in the
+conflict marker annotations when re-merging, the original filename is
+not available from the <<CFI,Conflicted file info>> and thus you would
+be losing information that might help the user resolve the conflict.
+
+[[DEPMERGE]]
+DEPRECATED DESCRIPTION
+----------------------
+
+Per the <<NEWMERGE,DESCRIPTION>> and unlike the rest of this
+documentation, this section describes the deprecated `--trivial-merge`
+mode.
+
+Other than the optional `--trivial-merge`, this mode accepts no
+options.
+
+This mode reads three tree-ish, and outputs trivial merge results and
+conflicting stages to the standard output in a semi-diff format.
+Since this was designed for higher level scripts to consume and merge
+the results back into the index, it omits entries that match
+<branch1>.  The result of this second form is similar to what
+three-way 'git read-tree -m' does, but instead of storing the results
+in the index, the command outputs the entries to the standard output.
+
+This form not only has limited applicability (a trivial merge cannot
+handle content merges of individual files, rename detection, proper
+directory/file conflict handling, etc.), the output format is also
+difficult to work with, and it will generally be less performant than
+the first form even on successful merges (especially if working in
+large repositories).
 
 GIT
 ---
diff --git a/Documentation/git-merge.txt b/Documentation/git-merge.txt
index 3125473..2d6a139 100644
--- a/Documentation/git-merge.txt
+++ b/Documentation/git-merge.txt
@@ -90,10 +90,7 @@
 If `--log` is specified, a shortlog of the commits being merged
 will be appended to the specified message.
 
---rerere-autoupdate::
---no-rerere-autoupdate::
-	Allow the rerere mechanism to update the index with the
-	result of auto-conflict resolution if possible.
+include::rerere-options.txt[]
 
 --overwrite-ignore::
 --no-overwrite-ignore::
@@ -386,13 +383,16 @@
 
 CONFIGURATION
 -------------
-include::config/merge.txt[]
 
 branch.<name>.mergeOptions::
 	Sets default options for merging into branch <name>. The syntax and
 	supported options are the same as those of 'git merge', but option
 	values containing whitespace characters are currently not supported.
 
+include::includes/cmd-config-section-rest.txt[]
+
+include::config/merge.txt[]
+
 SEE ALSO
 --------
 linkgit:git-fmt-merge-msg[1], linkgit:git-pull[1],
diff --git a/Documentation/git-mergetool.txt b/Documentation/git-mergetool.txt
index f784027..c44e205 100644
--- a/Documentation/git-mergetool.txt
+++ b/Documentation/git-mergetool.txt
@@ -102,6 +102,9 @@
 CONFIGURATION
 -------------
 :git-mergetool: 1
+
+include::includes/cmd-config-section-all.txt[]
+
 include::config/mergetool.txt[]
 
 TEMPORARY FILES
diff --git a/Documentation/git-multi-pack-index.txt b/Documentation/git-multi-pack-index.txt
index c588fb9..a48c3d5 100644
--- a/Documentation/git-multi-pack-index.txt
+++ b/Documentation/git-multi-pack-index.txt
@@ -128,8 +128,8 @@
 SEE ALSO
 --------
 See link:technical/multi-pack-index.html[The Multi-Pack-Index Design
-Document] and link:technical/pack-format.html[The Multi-Pack-Index
-Format] for more information on the multi-pack-index feature.
+Document] and linkgit:gitformat-pack[5] for more information on the
+multi-pack-index feature and its file format.
 
 
 GIT
diff --git a/Documentation/git-notes.txt b/Documentation/git-notes.txt
index 0a42006..efbc10f 100644
--- a/Documentation/git-notes.txt
+++ b/Documentation/git-notes.txt
@@ -44,7 +44,7 @@
 after a three dash separator line.
 
 To change which notes are shown by 'git log', see the
-"notes.displayRef" configuration in linkgit:git-log[1].
+"notes.displayRef" discussion in <<CONFIGURATION>>.
 
 See the "notes.rewrite.<command>" configuration for a way to carry
 notes across commands that rewrite commits.
@@ -307,6 +307,7 @@
 some special-purpose tools to do something useful with them.
 
 
+[[CONFIGURATION]]
 CONFIGURATION
 -------------
 
@@ -316,57 +317,9 @@
 	This setting can be overridden through the environment and
 	command line.
 
-notes.mergeStrategy::
-	Which merge strategy to choose by default when resolving notes
-	conflicts.  Must be one of `manual`, `ours`, `theirs`, `union`, or
-	`cat_sort_uniq`.  Defaults to `manual`.  See "NOTES MERGE STRATEGIES"
-	section above for more information on each strategy.
-+
-This setting can be overridden by passing the `--strategy` option.
+include::includes/cmd-config-section-rest.txt[]
 
-notes.<name>.mergeStrategy::
-	Which merge strategy to choose when doing a notes merge into
-	refs/notes/<name>.  This overrides the more general
-	"notes.mergeStrategy".  See the "NOTES MERGE STRATEGIES" section above
-	for more information on each available strategy.
-
-notes.displayRef::
-	Which ref (or refs, if a glob or specified more than once), in
-	addition to the default set by `core.notesRef` or
-	`GIT_NOTES_REF`, to read notes from when showing commit
-	messages with the 'git log' family of commands.
-	This setting can be overridden on the command line or by the
-	`GIT_NOTES_DISPLAY_REF` environment variable.
-	See linkgit:git-log[1].
-
-notes.rewrite.<command>::
-	When rewriting commits with <command> (currently `amend` or
-	`rebase`), if this variable is `false`, git will not copy
-	notes from the original to the rewritten commit.  Defaults to
-	`true`.  See also "`notes.rewriteRef`" below.
-+
-This setting can be overridden by the `GIT_NOTES_REWRITE_REF`
-environment variable.
-
-notes.rewriteMode::
-	When copying notes during a rewrite, what to do if the target
-	commit already has a note.  Must be one of `overwrite`,
-	`concatenate`, `cat_sort_uniq`, or `ignore`.  Defaults to
-	`concatenate`.
-+
-This setting can be overridden with the `GIT_NOTES_REWRITE_MODE`
-environment variable.
-
-notes.rewriteRef::
-	When copying notes during a rewrite, specifies the (fully
-	qualified) ref whose notes should be copied.  May be a glob,
-	in which case notes in all matching refs will be copied.  You
-	may also specify this configuration several times.
-+
-Does not have a default value; you must configure this variable to
-enable note rewriting.
-+
-Can be overridden with the `GIT_NOTES_REWRITE_REF` environment variable.
+include::config/notes.txt[]
 
 
 ENVIRONMENT
diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt
index 2f25aa3..def7657 100644
--- a/Documentation/git-push.txt
+++ b/Documentation/git-push.txt
@@ -692,6 +692,13 @@
 
 include::transfer-data-leaks.txt[]
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/push.txt[]
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/git-range-diff.txt b/Documentation/git-range-diff.txt
index fe350d7..0b39371 100644
--- a/Documentation/git-range-diff.txt
+++ b/Documentation/git-range-diff.txt
@@ -12,6 +12,7 @@
 	[--no-dual-color] [--creation-factor=<factor>]
 	[--left-only | --right-only]
 	( <range1> <range2> | <rev1>...<rev2> | <base> <rev1> <rev2> )
+	[[--] <path>...]
 
 DESCRIPTION
 -----------
@@ -19,6 +20,9 @@
 This command shows the differences between two versions of a patch
 series, or more generally, two commit ranges (ignoring merge commits).
 
+In the presence of `<path>` arguments, these commit ranges are limited
+accordingly.
+
 To that end, it first finds pairs of commits from both commit ranges
 that correspond with each other. Two commits are said to correspond when
 the diff between their patches (i.e. the author information, the commit
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index a872ab0..9cb8931 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -376,10 +376,7 @@
 +
 See also INCOMPATIBLE OPTIONS below.
 
---rerere-autoupdate::
---no-rerere-autoupdate::
-	Allow the rerere mechanism to update the index with the
-	result of auto-conflict resolution if possible.
+include::rerere-options.txt[]
 
 -S[<keyid>]::
 --gpg-sign[=<keyid>]::
@@ -612,6 +609,15 @@
 start would be overridden by the presence of
 `rebase.rescheduleFailedExec=true` configuration.
 
+--update-refs::
+--no-update-refs::
+	Automatically force-update any branches that point to commits that
+	are being rebased. Any branches that are checked out in a worktree
+	are not updated in this way.
++
+If the configuration variable `rebase.updateRefs` is set, then this option
+can be used to override and disable this setting.
+
 INCOMPATIBLE OPTIONS
 --------------------
 
@@ -635,6 +641,7 @@
  * --empty=
  * --reapply-cherry-picks
  * --edit-todo
+ * --update-refs
  * --root when used in combination with --onto
 
 In addition, the following pairs of options are incompatible:
@@ -1252,6 +1259,8 @@
 CONFIGURATION
 -------------
 
+include::includes/cmd-config-section-all.txt[]
+
 include::config/rebase.txt[]
 include::config/sequencer.txt[]
 
diff --git a/Documentation/git-revert.txt b/Documentation/git-revert.txt
index 8463fe9..5016755 100644
--- a/Documentation/git-revert.txt
+++ b/Documentation/git-revert.txt
@@ -112,10 +112,7 @@
 	Pass the merge strategy-specific option through to the
 	merge strategy.  See linkgit:git-merge[1] for details.
 
---rerere-autoupdate::
---no-rerere-autoupdate::
-	Allow the rerere mechanism to update the index with the
-	result of auto-conflict resolution if possible.
+include::rerere-options.txt[]
 
 --reference::
 	Instead of starting the body of the log message with "This
@@ -145,6 +142,13 @@
 	changes. The revert only modifies the working tree and the
 	index.
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/revert.txt[]
+
 SEE ALSO
 --------
 linkgit:git-cherry-pick[1]
diff --git a/Documentation/git-send-email.txt b/Documentation/git-send-email.txt
index 41cd8cb..3290043 100644
--- a/Documentation/git-send-email.txt
+++ b/Documentation/git-send-email.txt
@@ -456,41 +456,9 @@
 CONFIGURATION
 -------------
 
-sendemail.aliasesFile::
-	To avoid typing long email addresses, point this to one or more
-	email aliases files.  You must also supply `sendemail.aliasFileType`.
+include::includes/cmd-config-section-all.txt[]
 
-sendemail.aliasFileType::
-	Format of the file(s) specified in sendemail.aliasesFile. Must be
-	one of 'mutt', 'mailrc', 'pine', 'elm', or 'gnus', or 'sendmail'.
-+
-What an alias file in each format looks like can be found in
-the documentation of the email program of the same name. The
-differences and limitations from the standard formats are
-described below:
-+
---
-sendmail;;
-*	Quoted aliases and quoted addresses are not supported: lines that
-	contain a `"` symbol are ignored.
-*	Redirection to a file (`/path/name`) or pipe (`|command`) is not
-	supported.
-*	File inclusion (`:include: /path/name`) is not supported.
-*	Warnings are printed on the standard error output for any
-	explicitly unsupported constructs, and any other lines that are not
-	recognized by the parser.
---
-
-sendemail.multiEdit::
-	If true (default), a single editor instance will be spawned to edit
-	files you have to edit (patches when `--annotate` is used, and the
-	summary when `--compose` is used). If false, files will be edited one
-	after the other, spawning a new editor each time.
-
-sendemail.confirm::
-	Sets the default for whether to confirm before sending. Must be
-	one of 'always', 'never', 'cc', 'compose', or 'auto'. See `--confirm`
-	in the previous section for the meaning of these values.
+include::config/sendemail.txt[]
 
 EXAMPLES
 --------
diff --git a/Documentation/git-show-branch.txt b/Documentation/git-show-branch.txt
index 5cc2fce..e5ec6b4 100644
--- a/Documentation/git-show-branch.txt
+++ b/Documentation/git-show-branch.txt
@@ -199,6 +199,13 @@
 Without `--list`, the output also shows how these tips are
 topologically related with each other.
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/showbranch.txt[]
+
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/git-stash.txt b/Documentation/git-stash.txt
index 6e15f47..c5d7091 100644
--- a/Documentation/git-stash.txt
+++ b/Documentation/git-stash.txt
@@ -382,6 +382,13 @@
 xargs git log --merges --no-walk --grep=WIP
 ----------------------------------------------------------------
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/stash.txt[]
+
 
 SEE ALSO
 --------
diff --git a/Documentation/git-switch.txt b/Documentation/git-switch.txt
index bbcbdce..c60fc9c 100644
--- a/Documentation/git-switch.txt
+++ b/Documentation/git-switch.txt
@@ -265,6 +265,13 @@
 $ git switch -c good-surprises
 ------------
 
+CONFIGURATION
+-------------
+
+include::includes/cmd-config-section-all.txt[]
+
+include::config/checkout.txt[]
+
 SEE ALSO
 --------
 linkgit:git-checkout[1],
diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt
index 5ea2f2c..f4bb9c5 100644
--- a/Documentation/git-update-index.txt
+++ b/Documentation/git-update-index.txt
@@ -420,7 +420,7 @@
 However, these commands will sometimes write these files anyway in
 important cases such as conflicts during a merge or rebase.  Git
 commands will also avoid treating the lack of such files as an
-intentional deletion; for example `git add -u` will not not stage a
+intentional deletion; for example `git add -u` will not stage a
 deletion for these files and `git commit -a` will not make a commit
 deleting them either.
 
diff --git a/Documentation/git-upload-pack.txt b/Documentation/git-upload-pack.txt
index 8f87b23..b656b47 100644
--- a/Documentation/git-upload-pack.txt
+++ b/Documentation/git-upload-pack.txt
@@ -39,10 +39,9 @@
 --http-backend-info-refs::
 	Used by linkgit:git-http-backend[1] to serve up
 	`$GIT_URL/info/refs?service=git-upload-pack` requests. See
-	"Smart Clients" in link:technical/http-protocol.html[the HTTP
-	transfer protocols] documentation and "HTTP Transport" in
-	link:technical/protocol-v2.html[the Git Wire Protocol, Version
-	2] documentation. Also understood by
+	"Smart Clients" in linkgit:gitprotocol-http[5] and "HTTP
+	Transport" in the linkgit:gitprotocol-v2[5]
+	documentation. Also understood by
 	linkgit:git-receive-pack[1].
 
 <directory>::
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 47a6095..0ef7f5e 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -339,6 +339,23 @@
 
 include::cmds-guide.txt[]
 
+Repository, command and file interfaces
+---------------------------------------
+
+This documentation discusses repository and command interfaces which
+users are expected to interact with directly. See `--user-formats` in
+linkgit:git-help[1] for more details on the critera.
+
+include::cmds-userinterfaces.txt[]
+
+File formats, protocols and other developer interfaces
+------------------------------------------------------
+
+This documentation discusses file formats, over-the-wire protocols and
+other git developer interfaces. See `--developer-interfaces` in
+linkgit:git-help[1].
+
+include::cmds-developerinterfaces.txt[]
 
 Configuration Mechanism
 -----------------------
diff --git a/Documentation/technical/bundle-format.txt b/Documentation/gitformat-bundle.txt
similarity index 79%
rename from Documentation/technical/bundle-format.txt
rename to Documentation/gitformat-bundle.txt
index b9be864..00e0a20 100644
--- a/Documentation/technical/bundle-format.txt
+++ b/Documentation/gitformat-bundle.txt
@@ -1,11 +1,33 @@
-= Git bundle v2 format
+gitformat-bundle(5)
+===================
 
-The Git bundle format is a format that represents both refs and Git objects.
+NAME
+----
+gitformat-bundle - The bundle file format
 
-== Format
+
+SYNOPSIS
+--------
+[verse]
+*.bundle
+*.bdl
+
+DESCRIPTION
+-----------
+
+The Git bundle format is a format that represents both refs and Git
+objects. A bundle is a header in a format similar to
+linkgit:git-show-ref[1] followed by a pack in *.pack format.
+
+The format is created and read by the linkgit:git-bundle[1] command,
+and supported by e.g. linkgit:git-fetch[1] and linkgit:git-clone[1].
+
+
+FORMAT
+------
 
 We will use ABNF notation to define the Git bundle format. See
-protocol-common.txt for the details.
+linkgit:gitprotocol-common[5] for the details.
 
 A v2 bundle looks like this:
 
@@ -36,7 +58,9 @@
 pack         = ... ; packfile
 ----
 
-== Semantics
+
+SEMANTICS
+---------
 
 A Git bundle consists of several parts.
 
@@ -62,13 +86,15 @@
 This is a comment and it has no specific meaning. The writer of the bundle MAY
 put any string here. The reader of the bundle MUST ignore the comment.
 
-=== Note on the shallow clone and a Git bundle
+Note on the shallow clone and a Git bundle
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Note that the prerequisites does not represent a shallow-clone boundary. The
 semantics of the prerequisites and the shallow-clone boundaries are different,
 and the Git bundle v2 format cannot represent a shallow clone repository.
 
-== Capabilities
+CAPABILITIES
+------------
 
 Because there is no opportunity for negotiation, unknown capabilities cause 'git
 bundle' to abort.
@@ -79,3 +105,7 @@
 * `filter` specifies an object filter as in the `--filter` option in
   linkgit:git-rev-list[1]. The resulting pack-file must be marked as a
   `.promisor` pack-file after it is unbundled.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/technical/chunk-format.txt b/Documentation/gitformat-chunk.txt
similarity index 88%
rename from Documentation/technical/chunk-format.txt
rename to Documentation/gitformat-chunk.txt
index 593614f..57202ed 100644
--- a/Documentation/technical/chunk-format.txt
+++ b/Documentation/gitformat-chunk.txt
@@ -1,12 +1,25 @@
-Chunk-based file formats
-========================
+gitformat-chunk(5)
+==================
+
+NAME
+----
+gitformat-chunk - Chunk-based file formats
+
+SYNOPSIS
+--------
+
+Used by linkgit:gitformat-commit-graph[5] and the "MIDX" format (see
+the pack format documentation in linkgit:gitformat-pack[5]).
+
+DESCRIPTION
+-----------
 
 Some file formats in Git use a common concept of "chunks" to describe
 sections of the file. This allows structured access to a large file by
 scanning a small "table of contents" for the remaining data. This common
 format is used by the `commit-graph` and `multi-pack-index` files. See
-link:technical/pack-format.html[the `multi-pack-index` format] and
-link:technical/commit-graph-format.html[the `commit-graph` format] for
+the `multi-pack-index` format in linkgit:gitformat-pack[5] and
+the `commit-graph` format in linkgit:gitformat-commit-graph[5] for
 how they use the chunks to describe structured data.
 
 A chunk-based file format begins with some header information custom to
@@ -108,9 +121,13 @@
 * *commit-graph:* see `write_commit_graph_file()` and `parse_commit_graph()`
   in `commit-graph.c` for how the chunk-format API is used to write and
   parse the commit-graph file format documented in
-  link:technical/commit-graph-format.html[the commit-graph file format].
+  the commit-graph file format in linkgit:gitformat-commit-graph[5].
 
 * *multi-pack-index:* see `write_midx_internal()` and `load_multi_pack_index()`
   in `midx.c` for how the chunk-format API is used to write and
   parse the multi-pack-index file format documented in
-  link:technical/pack-format.html[the multi-pack-index file format].
+  the multi-pack-index file format section of linkgit:gitformat-pack[5].
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/technical/commit-graph-format.txt b/Documentation/gitformat-commit-graph.txt
similarity index 86%
rename from Documentation/technical/commit-graph-format.txt
rename to Documentation/gitformat-commit-graph.txt
index 484b185..7324665 100644
--- a/Documentation/technical/commit-graph-format.txt
+++ b/Documentation/gitformat-commit-graph.txt
@@ -1,5 +1,18 @@
-Git commit graph format
-=======================
+gitformat-commit-graph(5)
+=========================
+
+NAME
+----
+gitformat-commit-graph - Git commit graph format
+
+SYNOPSIS
+--------
+[verse]
+$GIT_DIR/objects/info/commit-graph
+$GIT_DIR/objects/info/commit-graphs/*
+
+DESCRIPTION
+-----------
 
 The Git commit graph stores a list of commit OIDs and some associated
 metadata, including:
@@ -30,7 +43,7 @@
 
 All multi-byte numbers are in network byte order.
 
-HEADER:
+=== HEADER:
 
   4-byte signature:
       The signature is: {'C', 'G', 'P', 'H'}
@@ -52,7 +65,7 @@
       We infer the length (H*B) of the Base Graphs chunk
       from this value.
 
-CHUNK LOOKUP:
+=== CHUNK LOOKUP:
 
   (C + 1) * 12 bytes listing the table of contents for the chunks:
       First 4 bytes describe the chunk id. Value 0 is a terminating label.
@@ -62,23 +75,23 @@
       ID appears at most once.
 
   The CHUNK LOOKUP matches the table of contents from
-  link:technical/chunk-format.html[the chunk-based file format].
+  the chunk-based file format, see linkgit:gitformat-chunk[5]
 
   The remaining data in the body is described one chunk at a time, and
   these chunks may be given in any order. Chunks are required unless
   otherwise specified.
 
-CHUNK DATA:
+=== CHUNK DATA:
 
-  OID Fanout (ID: {'O', 'I', 'D', 'F'}) (256 * 4 bytes)
+==== OID Fanout (ID: {'O', 'I', 'D', 'F'}) (256 * 4 bytes)
       The ith entry, F[i], stores the number of OIDs with first
       byte at most i. Thus F[255] stores the total
       number of commits (N).
 
-  OID Lookup (ID: {'O', 'I', 'D', 'L'}) (N * H bytes)
+====  OID Lookup (ID: {'O', 'I', 'D', 'L'}) (N * H bytes)
       The OIDs for all commits in the graph, sorted in ascending order.
 
-  Commit Data (ID: {'C', 'D', 'A', 'T' }) (N * (H + 16) bytes)
+====  Commit Data (ID: {'C', 'D', 'A', 'T' }) (N * (H + 16) bytes)
     * The first H bytes are for the OID of the root tree.
     * The next 8 bytes are for the positions of the first two parents
       of the ith commit. Stores value 0x70000000 if no parent in that
@@ -93,7 +106,7 @@
       2 bits of the lowest byte, storing the 33rd and 34th bit of the
       commit time.
 
-  Generation Data (ID: {'G', 'D', 'A', '2' }) (N * 4 bytes) [Optional]
+==== Generation Data (ID: {'G', 'D', 'A', '2' }) (N * 4 bytes) [Optional]
     * This list of 4-byte values store corrected commit date offsets for the
       commits, arranged in the same order as commit data chunk.
     * If the corrected commit date offset cannot be stored within 31 bits,
@@ -104,7 +117,7 @@
       by compatible versions of Git and in case of split commit-graph chains,
       the topmost layer also has Generation Data chunk.
 
-  Generation Data Overflow (ID: {'G', 'D', 'O', '2' }) [Optional]
+==== Generation Data Overflow (ID: {'G', 'D', 'O', '2' }) [Optional]
     * This list of 8-byte values stores the corrected commit date offsets
       for commits with corrected commit date offsets that cannot be
       stored within 31 bits.
@@ -112,7 +125,7 @@
       chunk is present and atleast one corrected commit date offset cannot
       be stored within 31 bits.
 
-  Extra Edge List (ID: {'E', 'D', 'G', 'E'}) [Optional]
+==== Extra Edge List (ID: {'E', 'D', 'G', 'E'}) [Optional]
       This list of 4-byte values store the second through nth parents for
       all octopus merges. The second parent value in the commit data stores
       an array position within this list along with the most-significant bit
@@ -120,14 +133,14 @@
       positions for the parents until reaching a value with the most-significant
       bit on. The other bits correspond to the position of the last parent.
 
-  Bloom Filter Index (ID: {'B', 'I', 'D', 'X'}) (N * 4 bytes) [Optional]
+==== Bloom Filter Index (ID: {'B', 'I', 'D', 'X'}) (N * 4 bytes) [Optional]
     * The ith entry, BIDX[i], stores the number of bytes in all Bloom filters
       from commit 0 to commit i (inclusive) in lexicographic order. The Bloom
       filter for the i-th commit spans from BIDX[i-1] to BIDX[i] (plus header
       length), where BIDX[-1] is 0.
     * The BIDX chunk is ignored if the BDAT chunk is not present.
 
-  Bloom Filter Data (ID: {'B', 'D', 'A', 'T'}) [Optional]
+==== Bloom Filter Data (ID: {'B', 'D', 'A', 'T'}) [Optional]
     * It starts with header consisting of three unsigned 32-bit integers:
       - Version of the hash algorithm being used. We currently only support
 	value 1 which corresponds to the 32-bit version of the murmur3 hash
@@ -147,13 +160,13 @@
       of length one, with either all bits set to zero or one respectively.
     * The BDAT chunk is present if and only if BIDX is present.
 
-  Base Graphs List (ID: {'B', 'A', 'S', 'E'}) [Optional]
+==== Base Graphs List (ID: {'B', 'A', 'S', 'E'}) [Optional]
       This list of H-byte hashes describe a set of B commit-graph files that
       form a commit-graph chain. The graph position for the ith commit in this
       file's OID Lookup chunk is equal to i plus the number of commits in all
       base graphs.  If B is non-zero, this chunk must exist.
 
-TRAILER:
+=== TRAILER:
 
 	H-byte HASH-checksum of all of the above.
 
@@ -164,3 +177,7 @@
 possibly erroneous data in these chunks with the IDs "GDAT" and "GDOV". By
 changing the IDs, newer versions of Git will silently ignore those older
 chunks and write the new information without trusting the incorrect data.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/technical/index-format.txt b/Documentation/gitformat-index.txt
similarity index 97%
rename from Documentation/technical/index-format.txt
rename to Documentation/gitformat-index.txt
index f691c20..015cb21 100644
--- a/Documentation/technical/index-format.txt
+++ b/Documentation/gitformat-index.txt
@@ -1,5 +1,19 @@
+gitformat-index(5)
+==================
+
+NAME
+----
+gitformat-index - Git index format
+
+SYNOPSIS
+--------
+[verse]
+$GIT_DIR/index
+
+DESCRIPTION
+-----------
+
 Git index format
-================
 
 == The Git index file has the following format
 
@@ -125,7 +139,7 @@
     entry is encoded as if the path name for the previous entry is an
     empty string).  At the beginning of an entry, an integer N in the
     variable width encoding (the same encoding as the offset is encoded
-    for OFS_DELTA pack entries; see pack-format.txt) is stored, followed
+    for OFS_DELTA pack entries; see linkgit:gitformat-pack[5]) is stored, followed
     by a NUL-terminated string S.  Removing N bytes from the end of the
     path name for the previous entry, and replacing it with the string S
     yields the path name for this entry.
@@ -402,3 +416,7 @@
   with signature { 's', 'd', 'i', 'r' }. Like the split-index extension,
   tools should avoid interacting with a sparse index unless they understand
   this extension.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/technical/pack-format.txt b/Documentation/gitformat-pack.txt
similarity index 72%
rename from Documentation/technical/pack-format.txt
rename to Documentation/gitformat-pack.txt
index b520aa9..e06af02 100644
--- a/Documentation/technical/pack-format.txt
+++ b/Documentation/gitformat-pack.txt
@@ -1,5 +1,30 @@
-Git pack format
-===============
+gitformat-pack(5)
+=================
+
+NAME
+----
+gitformat-pack - Git pack format
+
+
+SYNOPSIS
+--------
+[verse]
+$GIT_DIR/objects/pack/pack-*.{pack,idx}
+$GIT_DIR/objects/pack/pack-*.rev
+$GIT_DIR/objects/pack/pack-*.mtimes
+$GIT_DIR/objects/pack/multi-pack-index
+
+DESCRIPTION
+-----------
+
+The Git pack format is now Git stores most of its primary repository
+data. Over the lietime af a repository loose objects (if any) and
+smaller packs are consolidated into larger pack(s). See
+linkgit:git-gc[1] and linkgit:git-pack-objects[1].
+
+The pack format is also used over-the-wire, see
+e.g. linkgit:gitprotocol-v2[5], as well as being a part of
+other container formats in the case of linkgit:gitformat-bundle[5].
 
 == Checksums and object IDs
 
@@ -356,7 +381,7 @@
 	    using the next chunk position if necessary.)
 
 	The CHUNK LOOKUP matches the table of contents from
-	link:technical/chunk-format.html[the chunk-based file format].
+	the chunk-based file format, see linkgit:gitformat-chunk[5].
 
 	The remaining data in the body is described one chunk at a time, and
 	these chunks may be given in any order. Chunks are required unless
@@ -482,3 +507,132 @@
 
 The MIDX's reverse index is stored in the optional 'RIDX' chunk within
 the MIDX itself.
+
+== cruft packs
+
+The cruft packs feature offer an alternative to Git's traditional mechanism of
+removing unreachable objects. This document provides an overview of Git's
+pruning mechanism, and how a cruft pack can be used instead to accomplish the
+same.
+
+=== Background
+
+To remove unreachable objects from your repository, Git offers `git repack -Ad`
+(see linkgit:git-repack[1]). Quoting from the documentation:
+
+----
+[...] unreachable objects in a previous pack become loose, unpacked objects,
+instead of being left in the old pack. [...] loose unreachable objects will be
+pruned according to normal expiry rules with the next 'git gc' invocation.
+----
+
+Unreachable objects aren't removed immediately, since doing so could race with
+an incoming push which may reference an object which is about to be deleted.
+Instead, those unreachable objects are stored as loose objects and stay that way
+until they are older than the expiration window, at which point they are removed
+by linkgit:git-prune[1].
+
+Git must store these unreachable objects loose in order to keep track of their
+per-object mtimes. If these unreachable objects were written into one big pack,
+then either freshening that pack (because an object contained within it was
+re-written) or creating a new pack of unreachable objects would cause the pack's
+mtime to get updated, and the objects within it would never leave the expiration
+window. Instead, objects are stored loose in order to keep track of the
+individual object mtimes and avoid a situation where all cruft objects are
+freshened at once.
+
+This can lead to undesirable situations when a repository contains many
+unreachable objects which have not yet left the grace period. Having large
+directories in the shards of `.git/objects` can lead to decreased performance in
+the repository. But given enough unreachable objects, this can lead to inode
+starvation and degrade the performance of the whole system. Since we
+can never pack those objects, these repositories often take up a large amount of
+disk space, since we can only zlib compress them, but not store them in delta
+chains.
+
+=== Cruft packs
+
+A cruft pack eliminates the need for storing unreachable objects in a loose
+state by including the per-object mtimes in a separate file alongside a single
+pack containing all loose objects.
+
+A cruft pack is written by `git repack --cruft` when generating a new pack.
+linkgit:git-pack-objects[1]'s `--cruft` option. Note that `git repack --cruft`
+is a classic all-into-one repack, meaning that everything in the resulting pack is
+reachable, and everything else is unreachable. Once written, the `--cruft`
+option instructs `git repack` to generate another pack containing only objects
+not packed in the previous step (which equates to packing all unreachable
+objects together). This progresses as follows:
+
+  1. Enumerate every object, marking any object which is (a) not contained in a
+     kept-pack, and (b) whose mtime is within the grace period as a traversal
+     tip.
+
+  2. Perform a reachability traversal based on the tips gathered in the previous
+     step, adding every object along the way to the pack.
+
+  3. Write the pack out, along with a `.mtimes` file that records the per-object
+     timestamps.
+
+This mode is invoked internally by linkgit:git-repack[1] when instructed to
+write a cruft pack. Crucially, the set of in-core kept packs is exactly the set
+of packs which will not be deleted by the repack; in other words, they contain
+all of the repository's reachable objects.
+
+When a repository already has a cruft pack, `git repack --cruft` typically only
+adds objects to it. An exception to this is when `git repack` is given the
+`--cruft-expiration` option, which allows the generated cruft pack to omit
+expired objects instead of waiting for linkgit:git-gc[1] to expire those objects
+later on.
+
+It is linkgit:git-gc[1] that is typically responsible for removing expired
+unreachable objects.
+
+=== Caution for mixed-version environments
+
+Repositories that have cruft packs in them will continue to work with any older
+version of Git. Note, however, that previous versions of Git which do not
+understand the `.mtimes` file will use the cruft pack's mtime as the mtime for
+all of the objects in it. In other words, do not expect older (pre-cruft pack)
+versions of Git to interpret or even read the contents of the `.mtimes` file.
+
+Note that having mixed versions of Git GC-ing the same repository can lead to
+unreachable objects never being completely pruned. This can happen under the
+following circumstances:
+
+  - An older version of Git running GC explodes the contents of an existing
+    cruft pack loose, using the cruft pack's mtime.
+  - A newer version running GC collects those loose objects into a cruft pack,
+    where the .mtime file reflects the loose object's actual mtimes, but the
+    cruft pack mtime is "now".
+
+Repeating this process will lead to unreachable objects not getting pruned as a
+result of repeatedly resetting the objects' mtimes to the present time.
+
+If you are GC-ing repositories in a mixed version environment, consider omitting
+the `--cruft` option when using linkgit:git-repack[1] and linkgit:git-gc[1], and
+leaving the `gc.cruftPacks` configuration unset until all writers understand
+cruft packs.
+
+=== Alternatives
+
+Notable alternatives to this design include:
+
+  - The location of the per-object mtime data, and
+  - Storing unreachable objects in multiple cruft packs.
+
+On the location of mtime data, a new auxiliary file tied to the pack was chosen
+to avoid complicating the `.idx` format. If the `.idx` format were ever to gain
+support for optional chunks of data, it may make sense to consolidate the
+`.mtimes` format into the `.idx` itself.
+
+Storing unreachable objects among multiple cruft packs (e.g., creating a new
+cruft pack during each repacking operation including only unreachable objects
+which aren't already stored in an earlier cruft pack) is significantly more
+complicated to construct, and so aren't pursued here. The obvious drawback to
+the current implementation is that the entire cruft pack must be re-written from
+scratch.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/technical/signature-format.txt b/Documentation/gitformat-signature.txt
similarity index 95%
rename from Documentation/technical/signature-format.txt
rename to Documentation/gitformat-signature.txt
index 166721b..a249869 100644
--- a/Documentation/technical/signature-format.txt
+++ b/Documentation/gitformat-signature.txt
@@ -1,7 +1,18 @@
-Git signature format
-====================
+gitformat-signature(5)
+======================
 
-== Overview
+NAME
+----
+gitformat-signature - Git cryptographic signature formats
+
+SYNOPSIS
+--------
+[verse]
+<[tag|commit] object header(s)>
+<over-the-wire protocol>
+
+DESCRIPTION
+-----------
 
 Git uses cryptographic signatures in various places, currently objects (tags,
 commits, mergetags) and transactions (pushes). In every case, the command which
@@ -200,3 +211,7 @@
     # gpg:          There is no indication that the signature belongs to the owner.
     # Primary key fingerprint: D4BE 2231 1AD3 131E 5EDA  29A4 6109 2E85 B722 7189
 ----
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/technical/protocol-capabilities.txt b/Documentation/gitprotocol-capabilities.txt
similarity index 96%
rename from Documentation/technical/protocol-capabilities.txt
rename to Documentation/gitprotocol-capabilities.txt
index 9dfade9..c6dcc7d 100644
--- a/Documentation/technical/protocol-capabilities.txt
+++ b/Documentation/gitprotocol-capabilities.txt
@@ -1,8 +1,20 @@
-Git Protocol Capabilities
-=========================
+gitprotocol-capabilities(5)
+===========================
+
+NAME
+----
+gitprotocol-capabilities - Protocol v0 and v1 capabilities
+
+SYNOPSIS
+--------
+[verse]
+<over-the-wire-protocol>
+
+DESCRIPTION
+-----------
 
 NOTE: this document describes capabilities for versions 0 and 1 of the pack
-protocol. For version 2, please refer to the link:protocol-v2.html[protocol-v2]
+protocol. For version 2, please refer to the linkgit:gitprotocol-v2[5]
 doc.
 
 Servers SHOULD support all capabilities defined in this document.
@@ -77,7 +89,7 @@
 multi_ack_detailed
 ------------------
 This is an extension of multi_ack that permits client to better
-understand the server's in-memory state. See pack-protocol.txt,
+understand the server's in-memory state. See linkgit:gitprotocol-pack[5],
 section "Packfile Negotiation" for more information.
 
 no-done
@@ -281,7 +293,7 @@
 this capability, after unpacking and updating references the server
 will respond with whether the packfile unpacked successfully and if
 each reference was updated successfully.  If any of those were not
-successful, it will send back an error message.  See pack-protocol.txt
+successful, it will send back an error message.  See linkgit:gitprotocol-pack[5]
 for example messages.
 
 report-status-v2
@@ -292,7 +304,7 @@
 the "proc-receive" hook.  The "proc-receive" hook may handle a command
 for a pseudo-reference which may create or update a reference with
 different name, new-oid, and old-oid.  While the capability
-'report-status' cannot report for such case.  See pack-protocol.txt
+'report-status' cannot report for such case.  See linkgit:gitprotocol-pack[5]
 for details.
 
 delete-refs
@@ -378,3 +390,7 @@
 current implementation uses trace2 session IDs (see
 link:api-trace2.html[api-trace2] for details), but this may change and users of
 the session ID should not rely on this fact.
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/technical/protocol-common.txt b/Documentation/gitprotocol-common.txt
similarity index 89%
rename from Documentation/technical/protocol-common.txt
rename to Documentation/gitprotocol-common.txt
index ecedb34..1486651 100644
--- a/Documentation/technical/protocol-common.txt
+++ b/Documentation/gitprotocol-common.txt
@@ -1,5 +1,20 @@
-Documentation Common to Pack and Http Protocols
-===============================================
+gitprotocol-common(5)
+=====================
+
+NAME
+----
+gitprotocol-common - Things common to various protocols
+
+SYNOPSIS
+--------
+[verse]
+<over-the-wire-protocol>
+
+DESCRIPTION
+-----------
+
+This document sets defines things common to various over-the-wire
+protocols and file formats used in Git.
 
 ABNF Notation
 -------------
@@ -97,3 +112,7 @@
   "000bfoobar\n"    "foobar\n"
   "0004"            ""
 ----
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/technical/http-protocol.txt b/Documentation/gitprotocol-http.txt
similarity index 97%
rename from Documentation/technical/http-protocol.txt
rename to Documentation/gitprotocol-http.txt
index cc5126c..ccc13f0 100644
--- a/Documentation/technical/http-protocol.txt
+++ b/Documentation/gitprotocol-http.txt
@@ -1,5 +1,19 @@
-HTTP transfer protocols
-=======================
+gitprotocol-http(5)
+===================
+
+NAME
+----
+gitprotocol-http - Git HTTP-based protocols
+
+
+SYNOPSIS
+--------
+[verse]
+<over-the-wire-protocol>
+
+
+DESCRIPTION
+-----------
 
 Git supports two HTTP based transfer protocols.  A "dumb" protocol
 which requires only a standard HTTP server on the server end of the
@@ -222,7 +236,7 @@
    S: 0000
 
 The client may send Extra Parameters (see
-Documentation/technical/pack-protocol.txt) as a colon-separated string
+linkgit:gitprotocol-pack[5]) as a colon-separated string
 in the Git-Protocol HTTP header.
 
 Uses the `--http-backend-info-refs` option to
@@ -512,11 +526,18 @@
 
 TODO: Document this further.
 
-
-References
+REFERENCES
 ----------
 
 http://www.ietf.org/rfc/rfc1738.txt[RFC 1738: Uniform Resource Locators (URL)]
 http://www.ietf.org/rfc/rfc2616.txt[RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1]
-link:technical/pack-protocol.html
-link:technical/protocol-capabilities.html
+
+SEE ALSO
+--------
+
+linkgit:gitprotocol-pack[5]
+linkgit:gitprotocol-capabilities[5]
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/gitprotocol-pack.txt
similarity index 97%
rename from Documentation/technical/pack-protocol.txt
rename to Documentation/gitprotocol-pack.txt
index e13a2c0..dd4108b 100644
--- a/Documentation/technical/pack-protocol.txt
+++ b/Documentation/gitprotocol-pack.txt
@@ -1,11 +1,23 @@
-Packfile transfer protocols
-===========================
+gitprotocol-pack(5)
+===================
+
+NAME
+----
+gitprotocol-pack - How packs are transferred over-the-wire
+
+SYNOPSIS
+--------
+[verse]
+<over-the-wire-protocol>
+
+DESCRIPTION
+-----------
 
 Git supports transferring data in packfiles over the ssh://, git://, http:// and
 file:// transports.  There exist two sets of protocols, one for pushing
 data from a client to a server and another for fetching data from a
 server to a client.  The three transports (ssh, git, file) use the same
-protocol to transfer data. http is documented in http-protocol.txt.
+protocol to transfer data. http is documented in linkgit:gitprotocol-http[5].
 
 The processes invoked in the canonical Git implementation are 'upload-pack'
 on the server side and 'fetch-pack' on the client side for fetching data;
@@ -18,7 +30,7 @@
 ---------------
 
 The descriptions below build on the pkt-line format described in
-protocol-common.txt. When the grammar indicate `PKT-LINE(...)`, unless
+linkgit:gitprotocol-common[5]. When the grammar indicate `PKT-LINE(...)`, unless
 otherwise noted the usual pkt-line LF rules apply: the sender SHOULD
 include a LF, but the receiver MUST NOT complain if it is not present.
 
@@ -60,7 +72,7 @@
 
 Servers that receive any such Extra Parameters MUST ignore all
 unrecognized keys. Currently, the only Extra Parameter recognized is
-"version" with a value of '1' or '2'.  See protocol-v2.txt for more
+"version" with a value of '1' or '2'.  See linkgit:gitprotocol-v2[5] for more
 information on protocol version 2.
 
 Git Transport
@@ -455,7 +467,7 @@
 the minimal amount of data that needs to be sent to the client is, the server
 will construct and send the required data in packfile format.
 
-See pack-format.txt for what the packfile itself actually looks like.
+See linkgit:gitformat-pack[5] for what the packfile itself actually looks like.
 
 If 'side-band' or 'side-band-64k' capabilities have been specified by
 the client, the server will send the packfile data multiplexed.
@@ -707,3 +719,7 @@
    S: 0018ok refs/heads/debug\n
    S: 002ang refs/heads/master non-fast-forward\n
 ----
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/technical/protocol-v2.txt b/Documentation/gitprotocol-v2.txt
similarity index 97%
rename from Documentation/technical/protocol-v2.txt
rename to Documentation/gitprotocol-v2.txt
index 8a877d2..c9c0f91 100644
--- a/Documentation/technical/protocol-v2.txt
+++ b/Documentation/gitprotocol-v2.txt
@@ -1,5 +1,17 @@
-Git Wire Protocol, Version 2
-============================
+gitprotocol-v2(5)
+=================
+
+NAME
+----
+gitprotocol-v2 - Git Wire Protocol, Version 2
+
+SYNOPSIS
+--------
+[verse]
+<over-the-wire-protocol>
+
+DESCRIPTION
+-----------
 
 This document presents a specification for a version 2 of Git's wire
 protocol.  Protocol v2 will improve upon v1 in the following ways:
@@ -26,8 +38,7 @@
 -------------------
 
 All communication is done using packet-line framing, just as in v1.  See
-`Documentation/technical/pack-protocol.txt` and
-`Documentation/technical/protocol-common.txt` for more information.
+linkgit:gitprotocol-pack[5] and linkgit:gitprotocol-common[5] for more information.
 
 In protocol v2 these special packets will have the following semantics:
 
@@ -42,7 +53,7 @@
 In general a client can request to speak protocol v2 by sending
 `version=2` through the respective side-channel for the transport being
 used which inevitably sets `GIT_PROTOCOL`.  More information can be
-found in `pack-protocol.txt` and `http-protocol.txt`, as well as the
+found in linkgit:gitprotocol-pack[5] and linkgit:gitprotocol-http[5], as well as the
 `GIT_PROTOCOL` definition in `git.txt`. In all cases the
 response from the server is the capability advertisement.
 
@@ -66,7 +77,7 @@
 ~~~~~~~~~~~~~~
 
 When using the http:// or https:// transport a client makes a "smart"
-info/refs request as described in `http-protocol.txt` and requests that
+info/refs request as described in linkgit:gitprotocol-http[5] and requests that
 v2 be used by supplying "version=2" in the `Git-Protocol` header.
 
    C: GET $GIT_URL/info/refs?service=git-upload-pack HTTP/1.0
@@ -566,3 +577,7 @@
 	attr = "size"
 
 	obj-info = obj-id SP obj-size
+
+GIT
+---
+Part of the linkgit:git[1] suite
diff --git a/Documentation/gitremote-helpers.txt b/Documentation/gitremote-helpers.txt
index 6f1e269..ed8da42 100644
--- a/Documentation/gitremote-helpers.txt
+++ b/Documentation/gitremote-helpers.txt
@@ -168,6 +168,9 @@
 	Can guarantee that when a clone is requested, the received
 	pack is self contained and is connected.
 
+'get'::
+	Can use the 'get' command to download a file from a given URI.
+
 If a helper advertises 'connect', Git will use it if possible and
 fall back to another capability if the helper requests so when
 connecting (see the 'connect' command under COMMANDS).
@@ -418,6 +421,12 @@
 +
 Supported if the helper has the "stateless-connect" capability.
 
+'get' <uri> <path>::
+	Downloads the file from the given `<uri>` to the given `<path>`. If
+	`<path>.temp` exists, then Git assumes that the `.temp` file is a
+	partial download from a previous attempt and will resume the
+	download from that position.
+
 If a fatal error occurs, the program writes the error message to
 stderr and exits. The caller should expect that a suitable error
 message has been printed if the child closes the connection without
diff --git a/Documentation/howto/recover-corrupted-object-harder.txt b/Documentation/howto/recover-corrupted-object-harder.txt
index 8994e25..5efb4fe 100644
--- a/Documentation/howto/recover-corrupted-object-harder.txt
+++ b/Documentation/howto/recover-corrupted-object-harder.txt
@@ -68,7 +68,7 @@
 has the git packed object header, which is variable-length. We want to
 strip that off so we can start playing with the zlib data directly. You
 can either work your way through it manually (the format is described in
-link:../technical/pack-format.html[Documentation/technical/pack-format.txt]),
+linkgit:gitformat-pack[5]),
 or you can walk through it in a debugger. I did the latter, creating a
 valid pack like:
 
diff --git a/Documentation/includes/cmd-config-section-all.txt b/Documentation/includes/cmd-config-section-all.txt
new file mode 100644
index 0000000..296a239
--- /dev/null
+++ b/Documentation/includes/cmd-config-section-all.txt
@@ -0,0 +1,3 @@
+Everything below this line in this section is selectively included
+from the linkgit:git-config[1] documentation. The content is the same
+as what's found there:
diff --git a/Documentation/includes/cmd-config-section-rest.txt b/Documentation/includes/cmd-config-section-rest.txt
new file mode 100644
index 0000000..b1e7682
--- /dev/null
+++ b/Documentation/includes/cmd-config-section-rest.txt
@@ -0,0 +1,3 @@
+Everything above this line in this section isn't included from the
+linkgit:git-config[1] documentation. The content that follows is the
+same as what's found there:
diff --git a/Documentation/lint-man-section-order.perl b/Documentation/lint-man-section-order.perl
index 425377d..02408a0 100755
--- a/Documentation/lint-man-section-order.perl
+++ b/Documentation/lint-man-section-order.perl
@@ -32,6 +32,9 @@
 		'SEE ALSO' => {
 			order => $order++,
 		},
+		'FILE FORMAT' => {
+			order => $order++,
+		},
 		'GIT' => {
 			required => 1,
 			order => $order++,
diff --git a/Documentation/rerere-options.txt b/Documentation/rerere-options.txt
new file mode 100644
index 0000000..c3321dd
--- /dev/null
+++ b/Documentation/rerere-options.txt
@@ -0,0 +1,9 @@
+--rerere-autoupdate::
+--no-rerere-autoupdate::
+	After the rerere mechanism reuses a recorded resolution on
+	the current conflict to update the files in the working
+	tree, allow it to also update the index with the result of
+	resolution.  `--no-rerere-autoupdate` is a good way to
+	double-check what `rerere` did and catch potential
+	mismerges, before committing the result to the index with a
+	separate `git add`.
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 195e74e..1837509 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -242,6 +242,7 @@
 	to `/dev/null` as the output does not have to be formatted.
 
 --disk-usage::
+--disk-usage=human::
 	Suppress normal output; instead, print the sum of the bytes used
 	for on-disk storage by the selected commits or objects. This is
 	equivalent to piping the output into `git cat-file
@@ -249,6 +250,8 @@
 	faster (especially with `--use-bitmap-index`). See the `CAVEATS`
 	section in linkgit:git-cat-file[1] for the limitations of what
 	"on-disk storage" means.
+	With the optional value `human`, on-disk storage size is shown
+	in human-readable string(e.g. 12.24 Kib, 3.50 Mib).
 endif::git-rev-list[]
 
 --cherry-mark::
@@ -389,12 +392,14 @@
 	merges from the resulting history, as there are no selected
 	commits contributing to this merge.
 
---ancestry-path::
+--ancestry-path[=<commit>]::
 	When given a range of commits to display (e.g. 'commit1..commit2'
-	or 'commit2 {caret}commit1'), only display commits that exist
-	directly on the ancestry chain between the 'commit1' and
-	'commit2', i.e. commits that are both descendants of 'commit1',
-	and ancestors of 'commit2'.
+	or 'commit2 {caret}commit1'), only display commits in that range
+	that are ancestors of <commit>, descendants of <commit>, or
+	<commit> itself.  If no commit is specified, use 'commit1' (the
+	excluded part of the range) as <commit>.  Can be passed multiple
+	times; if so, a commit is included if it is any of the commits
+	given or if it is an ancestor or descendant of one of them.
 
 A more detailed explanation follows.
 
@@ -568,11 +573,10 @@
 
 There is another simplification mode available:
 
---ancestry-path::
-	Limit the displayed commits to those directly on the ancestry
-	chain between the ``from'' and ``to'' commits in the given commit
-	range. I.e. only display commits that are ancestor of the ``to''
-	commit and descendants of the ``from'' commit.
+--ancestry-path[=<commit>]::
+	Limit the displayed commits to those which are an ancestor of
+	<commit>, or which are a descendant of <commit>, or are <commit>
+	itself.
 +
 As an example use case, consider the following commit history:
 +
@@ -604,6 +608,29 @@
 			       \
 				L--M
 -----------------------------------------------------------------------
++
+We can also use `--ancestry-path=D` instead of `--ancestry-path` which
+means the same thing when applied to the 'D..M' range but is just more
+explicit.
++
+If we instead are interested in a given topic within this range, and all
+commits affected by that topic, we may only want to view the subset of
+`D..M` which contain that topic in their ancestry path.  So, using
+`--ancestry-path=H D..M` for example would result in:
++
+-----------------------------------------------------------------------
+		E
+		 \
+		  G---H---I---J
+			       \
+				L--M
+-----------------------------------------------------------------------
++
+Whereas `--ancestry-path=K D..M` would result in
++
+-----------------------------------------------------------------------
+		K---------------L--M
+-----------------------------------------------------------------------
 
 Before discussing another option, `--show-pulls`, we need to
 create a new example history.
@@ -659,7 +686,7 @@
 not actually contribute a change to `file.txt`. They only merged a topic
 that was based on an older version of `file.txt`. This is a common
 issue in repositories using a workflow where many contributors work in
-parallel and merge their topic branches along a single trunk: manu
+parallel and merge their topic branches along a single trunk: many
 unrelated merges appear in the `--full-history` results.
 
 When using the `--simplify-merges` option, the commits `O` and `P`
diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt
index acfd5dc..c2a5e429 100644
--- a/Documentation/technical/api-parse-options.txt
+++ b/Documentation/technical/api-parse-options.txt
@@ -8,7 +8,8 @@
 ------
 
 The argument vector `argv[]` may usually contain mandatory or optional
-'non-option arguments', e.g. a filename or a branch, and 'options'.
+'non-option arguments', e.g. a filename or a branch, 'options', and
+'subcommands'.
 Options are optional arguments that start with a dash and
 that allow to change the behavior of a command.
 
@@ -48,6 +49,33 @@
   option, e.g. `-a -b --option -- --this-is-a-file` indicates that
   `--this-is-a-file` must not be processed as an option.
 
+Subcommands are special in a couple of ways:
+
+* Subcommands only have long form, and they have no double dash prefix, no
+  negated form, and no description, and they don't take any arguments, and
+  can't be abbreviated.
+
+* There must be exactly one subcommand among the arguments, or zero if the
+  command has a default operation mode.
+
+* All arguments following the subcommand are considered to be arguments of
+  the subcommand, and, conversely, arguments meant for the subcommand may
+  not preceed the subcommand.
+
+Therefore, if the options array contains at least one subcommand and
+`parse_options()` encounters the first dashless argument, it will either:
+
+* stop and return, if that dashless argument is a known subcommand, setting
+  `value` to the function pointer associated with that subcommand, storing
+  the name of the subcommand in argv[0], and leaving the rest of the
+  arguments unprocessed, or
+
+* stop and return, if it was invoked with the `PARSE_OPT_SUBCOMMAND_OPTIONAL`
+  flag and that dashless argument doesn't match any subcommands, leaving
+  `value` unchanged and the rest of the arguments unprocessed, or
+
+* show error and usage, and abort.
+
 Steps to parse options
 ----------------------
 
@@ -90,8 +118,8 @@
 	Keep the first argument, which contains the program name.  It's
 	removed from argv[] by default.
 
-`PARSE_OPT_KEEP_UNKNOWN`::
-	Keep unknown arguments instead of erroring out.  This doesn't
+`PARSE_OPT_KEEP_UNKNOWN_OPT`::
+	Keep unknown options instead of erroring out.  This doesn't
 	work for all combinations of arguments as users might expect
 	it to do.  E.g. if the first argument in `--unknown --known`
 	takes a value (which we can't know), the second one is
@@ -101,6 +129,8 @@
 	non-option, not as a value belonging to the unknown option,
 	the parser early.  That's why parse_options() errors out if
 	both options are set.
+	Note that non-option arguments are always kept, even without
+	this flag.
 
 `PARSE_OPT_NO_INTERNAL_HELP`::
 	By default, parse_options() handles `-h`, `--help` and
@@ -108,6 +138,13 @@
 	turns it off and allows one to add custom handlers for these
 	options, or to just leave them unknown.
 
+`PARSE_OPT_SUBCOMMAND_OPTIONAL`::
+	Don't error out when no subcommand is specified.
+
+Note that `PARSE_OPT_STOP_AT_NON_OPTION` is incompatible with subcommands;
+while `PARSE_OPT_KEEP_DASHDASH` and `PARSE_OPT_KEEP_UNKNOWN_OPT` can only be
+used with subcommands when combined with `PARSE_OPT_SUBCOMMAND_OPTIONAL`.
+
 Data Structure
 --------------
 
@@ -236,10 +273,14 @@
 `OPT_CMDMODE(short, long, &int_var, description, enum_val)`::
 	Define an "operation mode" option, only one of which in the same
 	group of "operating mode" options that share the same `int_var`
-	can be given by the user. `enum_val` is set to `int_var` when the
+	can be given by the user. `int_var` is set to `enum_val` when the
 	option is used, but an error is reported if other "operating mode"
 	option has already set its value to the same `int_var`.
+	In new commands consider using subcommands instead.
 
+`OPT_SUBCOMMAND(long, &fn_ptr, subcommand_fn)`::
+	Define a subcommand.  `subcommand_fn` is put into `fn_ptr` when
+	this subcommand is used.
 
 The last element of the array must be `OPT_END()`.
 
diff --git a/Documentation/technical/api-simple-ipc.txt b/Documentation/technical/api-simple-ipc.txt
index d79ad32..d44ada9 100644
--- a/Documentation/technical/api-simple-ipc.txt
+++ b/Documentation/technical/api-simple-ipc.txt
@@ -78,7 +78,7 @@
 client and server messages are unlimited in length and are terminated
 with a flush packet.
 
-The pkt-line routines (Documentation/technical/protocol-common.txt)
+The pkt-line routines (linkgit:gitprotocol-common[5])
 are used to simplify buffer management during message generation,
 transmission, and reception.  A flush packet is used to mark the end
 of the message.  This allows the sender to incrementally generate and
diff --git a/Documentation/technical/api-trace2.txt b/Documentation/technical/api-trace2.txt
index 77a150b..2afa28b 100644
--- a/Documentation/technical/api-trace2.txt
+++ b/Documentation/technical/api-trace2.txt
@@ -717,6 +717,7 @@
 {
 	"event":"def_param",
 	...
+	"scope":"global",
 	"param":"core.abbrev",
 	"value":"7"
 }
@@ -1207,6 +1208,45 @@
 This example also shows that thread names are assigned in a racy manner
 as each thread starts and allocates TLS storage.
 
+Config (def param) Events::
+
+	  Dump "interesting" config values to trace2 log.
++
+We can optionally emit configuration events, see
+`trace2.configparams` in linkgit:git-config[1] for how to enable
+it.
++
+----------------
+$ git config --system color.ui never
+$ git config --global color.ui always
+$ git config --local color.ui auto
+$ git config --list --show-scope | grep 'color.ui'
+system  color.ui=never
+global  color.ui=always
+local   color.ui=auto
+----------------
++
+Then, mark the config `color.ui` as "interesting" config with
+`GIT_TRACE2_CONFIG_PARAMS`:
++
+----------------
+$ export GIT_TRACE2_PERF_BRIEF=1
+$ export GIT_TRACE2_PERF=~/log.perf
+$ export GIT_TRACE2_CONFIG_PARAMS=color.ui
+$ git version
+...
+$ cat ~/log.perf
+d0 | main                     | version      |     |           |           |              | ...
+d0 | main                     | start        |     |  0.001642 |           |              | /usr/local/bin/git version
+d0 | main                     | cmd_name     |     |           |           |              | version (version)
+d0 | main                     | def_param    |     |           |           | scope:system | color.ui:never
+d0 | main                     | def_param    |     |           |           | scope:global | color.ui:always
+d0 | main                     | def_param    |     |           |           | scope:local  | color.ui:auto
+d0 | main                     | data         | r0  |  0.002100 |  0.002100 | fsync        | fsync/writeout-only:0
+d0 | main                     | data         | r0  |  0.002126 |  0.002126 | fsync        | fsync/hardware-flush:0
+d0 | main                     | exit         |     |  0.000470 |           |              | code:0
+d0 | main                     | atexit       |     |  0.000477 |           |              | code:0
+----------------
 == Future Work
 
 === Relationship to the Existing Trace Api (api-trace.txt)
diff --git a/Documentation/technical/bitmap-format.txt b/Documentation/technical/bitmap-format.txt
index a85f58f..c2e652b 100644
--- a/Documentation/technical/bitmap-format.txt
+++ b/Documentation/technical/bitmap-format.txt
@@ -72,6 +72,17 @@
 	    pack/MIDX. The format and meaning of the name-hash is
 	    described below.
 
+		** {empty}
+		BITMAP_OPT_LOOKUP_TABLE (0x10): :::
+		If present, the end of the bitmap file contains a table
+		containing a list of `N` <commit_pos, offset, xor_row>
+		triplets. The format and meaning of the table is described
+		below.
++
+NOTE: Unlike the xor_offset used to compress an individual bitmap,
+`xor_row` stores an *absolute* index into the lookup table, not a location
+relative to the current entry.
+
 	4-byte entry count (network byte order): ::
 	    The total count of entries (bitmapped commits) in this bitmap index.
 
@@ -216,3 +227,31 @@
 If implementations want to choose a different hashing scheme, they are
 free to do so, but MUST allocate a new header flag (because comparing
 hashes made under two different schemes would be pointless).
+
+Commit lookup table
+-------------------
+
+If the BITMAP_OPT_LOOKUP_TABLE flag is set, the last `N * (4 + 8 + 4)`
+bytes (preceding the name-hash cache and trailing hash) of the `.bitmap`
+file contains a lookup table specifying the information needed to get
+the desired bitmap from the entries without parsing previous unnecessary
+bitmaps.
+
+For a `.bitmap` containing `nr_entries` reachability bitmaps, the table
+contains a list of `nr_entries` <commit_pos, offset, xor_row> triplets
+(sorted in the ascending order of `commit_pos`). The content of i'th
+triplet is -
+
+	* {empty}
+	commit_pos (4 byte integer, network byte order): ::
+	It stores the object position of a commit (in the midx or pack
+	index).
+
+	* {empty}
+	offset (8 byte integer, network byte order): ::
+	The offset from which that commit's bitmap can be read.
+
+	* {empty}
+	xor_row (4 byte integer, network byte order): ::
+	The position of the triplet whose bitmap is used to compress
+	this one, or `0xffffffff` if no such bitmap exists.
diff --git a/Documentation/technical/bundle-uri.txt b/Documentation/technical/bundle-uri.txt
new file mode 100644
index 0000000..c25c423
--- /dev/null
+++ b/Documentation/technical/bundle-uri.txt
@@ -0,0 +1,573 @@
+Bundle URIs
+===========
+
+Git bundles are files that store a pack-file along with some extra metadata,
+including a set of refs and a (possibly empty) set of necessary commits. See
+linkgit:git-bundle[1] and link:bundle-format.txt[the bundle format] for more
+information.
+
+Bundle URIs are locations where Git can download one or more bundles in
+order to bootstrap the object database in advance of fetching the remaining
+objects from a remote.
+
+One goal is to speed up clones and fetches for users with poor network
+connectivity to the origin server. Another benefit is to allow heavy users,
+such as CI build farms, to use local resources for the majority of Git data
+and thereby reducing the load on the origin server.
+
+To enable the bundle URI feature, users can specify a bundle URI using
+command-line options or the origin server can advertise one or more URIs
+via a protocol v2 capability.
+
+Design Goals
+------------
+
+The bundle URI standard aims to be flexible enough to satisfy multiple
+workloads. The bundle provider and the Git client have several choices in
+how they create and consume bundle URIs.
+
+* Bundles can have whatever name the server desires. This name could refer
+  to immutable data by using a hash of the bundle contents. However, this
+  means that a new URI will be needed after every update of the content.
+  This might be acceptable if the server is advertising the URI (and the
+  server is aware of new bundles being generated) but would not be
+  ergonomic for users using the command line option.
+
+* The bundles could be organized specifically for bootstrapping full
+  clones, but could also be organized with the intention of bootstrapping
+  incremental fetches. The bundle provider must decide on one of several
+  organization schemes to minimize client downloads during incremental
+  fetches, but the Git client can also choose whether to use bundles for
+  either of these operations.
+
+* The bundle provider can choose to support full clones, partial clones,
+  or both. The client can detect which bundles are appropriate for the
+  repository's partial clone filter, if any.
+
+* The bundle provider can use a single bundle (for clones only), or a
+  list of bundles. When using a list of bundles, the provider can specify
+  whether or not the client needs _all_ of the bundle URIs for a full
+  clone, or if _any_ one of the bundle URIs is sufficient. This allows the
+  bundle provider to use different URIs for different geographies.
+
+* The bundle provider can organize the bundles using heuristics, such as
+  creation tokens, to help the client prevent downloading bundles it does
+  not need. When the bundle provider does not provide these heuristics,
+  the client can use optimizations to minimize how much of the data is
+  downloaded.
+
+* The bundle provider does not need to be associated with the Git server.
+  The client can choose to use the bundle provider without it being
+  advertised by the Git server.
+
+* The client can choose to discover bundle providers that are advertised
+  by the Git server. This could happen during `git clone`, during
+  `git fetch`, both, or neither. The user can choose which combination
+  works best for them.
+
+* The client can choose to configure a bundle provider manually at any
+  time. The client can also choose to specify a bundle provider manually
+  as a command-line option to `git clone`.
+
+Each repository is different and every Git server has different needs.
+Hopefully the bundle URI feature is flexible enough to satisfy all needs.
+If not, then the feature can be extended through its versioning mechanism.
+
+Server requirements
+-------------------
+
+To provide a server-side implementation of bundle servers, no other parts
+of the Git protocol are required. This allows server maintainers to use
+static content solutions such as CDNs in order to serve the bundle files.
+
+At the current scope of the bundle URI feature, all URIs are expected to
+be HTTP(S) URLs where content is downloaded to a local file using a `GET`
+request to that URL. The server could include authentication requirements
+to those requests with the aim of triggering the configured credential
+helper for secure access. (Future extensions could use "file://" URIs or
+SSH URIs.)
+
+Assuming a `200 OK` response from the server, the content at the URL is
+inspected. First, Git attempts to parse the file as a bundle file of
+version 2 or higher. If the file is not a bundle, then the file is parsed
+as a plain-text file using Git's config parser. The key-value pairs in
+that config file are expected to describe a list of bundle URIs. If
+neither of these parse attempts succeed, then Git will report an error to
+the user that the bundle URI provided erroneous data.
+
+Any other data provided by the server is considered erroneous.
+
+Bundle Lists
+------------
+
+The Git server can advertise bundle URIs using a set of `key=value` pairs.
+A bundle URI can also serve a plain-text file in the Git config format
+containing these same `key=value` pairs. In both cases, we consider this
+to be a _bundle list_. The pairs specify information about the bundles
+that the client can use to make decisions for which bundles to download
+and which to ignore.
+
+A few keys focus on properties of the list itself.
+
+bundle.version::
+	(Required) This value provides a version number for the bundle
+	list. If a future Git change enables a feature that needs the Git
+	client to react to a new key in the bundle list file, then this version
+	will increment. The only current version number is 1, and if any other
+	value is specified then Git will fail to use this file.
+
+bundle.mode::
+	(Required) This value has one of two values: `all` and `any`. When `all`
+	is specified, then the client should expect to need all of the listed
+	bundle URIs that match their repository's requirements. When `any` is
+	specified, then the client should expect that any one of the bundle URIs
+	that match their repository's requirements will suffice. Typically, the
+	`any` option is used to list a number of different bundle servers
+	located in different geographies.
+
+bundle.heuristic::
+	If this string-valued key exists, then the bundle list is designed to
+	work well with incremental `git fetch` commands. The heuristic signals
+	that there are additional keys available for each bundle that help
+	determine which subset of bundles the client should download. The only
+	heuristic currently planned is `creationToken`.
+
+The remaining keys include an `<id>` segment which is a server-designated
+name for each available bundle. The `<id>` must contain only alphanumeric
+and `-` characters.
+
+bundle.<id>.uri::
+	(Required) This string value is the URI for downloading bundle `<id>`.
+	If the URI begins with a protocol (`http://` or `https://`) then the URI
+	is absolute. Otherwise, the URI is interpreted as relative to the URI
+	used for the bundle list. If the URI begins with `/`, then that relative
+	path is relative to the domain name used for the bundle list. (This use
+	of relative paths is intended to make it easier to distribute a set of
+	bundles across a large number of servers or CDNs with different domain
+	names.)
+
+bundle.<id>.filter::
+	This string value represents an object filter that should also appear in
+	the header of this bundle. The server uses this value to differentiate
+	different kinds of bundles from which the client can choose those that
+	match their object filters.
+
+bundle.<id>.creationToken::
+	This value is a nonnegative 64-bit integer used for sorting the bundles
+	the list. This is used to download a subset of bundles during a fetch
+	when `bundle.heuristic=creationToken`.
+
+bundle.<id>.location::
+	This string value advertises a real-world location from where the bundle
+	URI is served. This can be used to present the user with an option for
+	which bundle URI to use or simply as an informative indicator of which
+	bundle URI was selected by Git. This is only valuable when
+	`bundle.mode` is `any`.
+
+Here is an example bundle list using the Git config format:
+
+	[bundle]
+		version = 1
+		mode = all
+		heuristic = creationToken
+
+	[bundle "2022-02-09-1644442601-daily"]
+		uri = https://bundles.example.com/git/git/2022-02-09-1644442601-daily.bundle
+		creationToken = 1644442601
+
+	[bundle "2022-02-02-1643842562"]
+		uri = https://bundles.example.com/git/git/2022-02-02-1643842562.bundle
+		creationToken = 1643842562
+
+	[bundle "2022-02-09-1644442631-daily-blobless"]
+		uri = 2022-02-09-1644442631-daily-blobless.bundle
+		creationToken = 1644442631
+		filter = blob:none
+
+	[bundle "2022-02-02-1643842568-blobless"]
+		uri = /git/git/2022-02-02-1643842568-blobless.bundle
+		creationToken = 1643842568
+		filter = blob:none
+
+This example uses `bundle.mode=all` as well as the
+`bundle.<id>.creationToken` heuristic. It also uses the `bundle.<id>.filter`
+options to present two parallel sets of bundles: one for full clones and
+another for blobless partial clones.
+
+Suppose that this bundle list was found at the URI
+`https://bundles.example.com/git/git/` and so the two blobless bundles have
+the following fully-expanded URIs:
+
+* `https://bundles.example.com/git/git/2022-02-09-1644442631-daily-blobless.bundle`
+* `https://bundles.example.com/git/git/2022-02-02-1643842568-blobless.bundle`
+
+Advertising Bundle URIs
+-----------------------
+
+If a user knows a bundle URI for the repository they are cloning, then
+they can specify that URI manually through a command-line option. However,
+a Git host may want to advertise bundle URIs during the clone operation,
+helping users unaware of the feature.
+
+The only thing required for this feature is that the server can advertise
+one or more bundle URIs. This advertisement takes the form of a new
+protocol v2 capability specifically for discovering bundle URIs.
+
+The client could choose an arbitrary bundle URI as an option _or_ select
+the URI with best performance by some exploratory checks. It is up to the
+bundle provider to decide if having multiple URIs is preferable to a
+single URI that is geodistributed through server-side infrastructure.
+
+Cloning with Bundle URIs
+------------------------
+
+The primary need for bundle URIs is to speed up clones. The Git client
+will interact with bundle URIs according to the following flow:
+
+1. The user specifies a bundle URI with the `--bundle-uri` command-line
+   option _or_ the client discovers a bundle list advertised by the
+   Git server.
+
+2. If the downloaded data from a bundle URI is a bundle, then the client
+   inspects the bundle headers to check that the prerequisite commit OIDs
+   are present in the client repository. If some are missing, then the
+   client delays unbundling until other bundles have been unbundled,
+   making those OIDs present. When all required OIDs are present, the
+   client unbundles that data using a refspec. The default refspec is
+   `+refs/heads/*:refs/bundles/*`, but this can be configured. These refs
+   are stored so that later `git fetch` negotiations can communicate the
+   bundled refs as `have`s, reducing the size of the fetch over the Git
+   protocol. To allow pruning refs from this ref namespace, Git may
+   introduce a numbered namespace (such as `refs/bundles/<i>/*`) such that
+   stale bundle refs can be deleted.
+
+3. If the file is instead a bundle list, then the client inspects the
+   `bundle.mode` to see if the list is of the `all` or `any` form.
+
+   a. If `bundle.mode=all`, then the client considers all bundle
+      URIs. The list is reduced based on the `bundle.<id>.filter` options
+      matching the client repository's partial clone filter. Then, all
+      bundle URIs are requested. If the `bundle.<id>.creationToken`
+      heuristic is provided, then the bundles are downloaded in decreasing
+      order by the creation token, stopping when a bundle has all required
+      OIDs. The bundles can then be unbundled in increasing creation token
+      order. The client stores the latest creation token as a heuristic
+      for avoiding future downloads if the bundle list does not advertise
+      bundles with larger creation tokens.
+
+   b. If `bundle.mode=any`, then the client can choose any one of the
+      bundle URIs to inspect. The client can use a variety of ways to
+      choose among these URIs. The client can also fallback to another URI
+      if the initial choice fails to return a result.
+
+Note that during a clone we expect that all bundles will be required, and
+heuristics such as `bundle.<uri>.creationToken` can be used to download
+bundles in chronological order or in parallel.
+
+If a given bundle URI is a bundle list with a `bundle.heuristic`
+value, then the client can choose to store that URI as its chosen bundle
+URI. The client can then navigate directly to that URI during later `git
+fetch` calls.
+
+When downloading bundle URIs, the client can choose to inspect the initial
+content before committing to downloading the entire content. This may
+provide enough information to determine if the URI is a bundle list or
+a bundle. In the case of a bundle, the client may inspect the bundle
+header to determine that all advertised tips are already in the client
+repository and cancel the remaining download.
+
+Fetching with Bundle URIs
+-------------------------
+
+When the client fetches new data, it can decide to fetch from bundle
+servers before fetching from the origin remote. This could be done via a
+command-line option, but it is more likely useful to use a config value
+such as the one specified during the clone.
+
+The fetch operation follows the same procedure to download bundles from a
+bundle list (although we do _not_ want to use parallel downloads here). We
+expect that the process will end when all prerequisite commit OIDs in a
+thin bundle are already in the object database.
+
+When using the `creationToken` heuristic, the client can avoid downloading
+any bundles if their creation tokenss are not larger than the stored
+creation token. After fetching new bundles, Git updates this local
+creation token.
+
+If the bundle provider does not provide a heuristic, then the client
+should attempt to inspect the bundle headers before downloading the full
+bundle data in case the bundle tips already exist in the client
+repository.
+
+Error Conditions
+----------------
+
+If the Git client discovers something unexpected while downloading
+information according to a bundle URI or the bundle list found at that
+location, then Git can ignore that data and continue as if it was not
+given a bundle URI. The remote Git server is the ultimate source of truth,
+not the bundle URI.
+
+Here are a few example error conditions:
+
+* The client fails to connect with a server at the given URI or a connection
+  is lost without any chance to recover.
+
+* The client receives a 400-level response (such as `404 Not Found` or
+  `401 Not Authorized`). The client should use the credential helper to
+  find and provide a credential for the URI, but match the semantics of
+  Git's other HTTP protocols in terms of handling specific 400-level
+  errors.
+
+* The server reports any other failure reponse.
+
+* The client receives data that is not parsable as a bundle or bundle list.
+
+* A bundle includes a filter that does not match expectations.
+
+* The client cannot unbundle the bundles because the prerequisite commit OIDs
+  are not in the object database and there are no more bundles to download.
+
+There are also situations that could be seen as wasteful, but are not
+error conditions:
+
+* The downloaded bundles contain more information than is requested by
+  the clone or fetch request. A primary example is if the user requests
+  a clone with `--single-branch` but downloads bundles that store every
+  reachable commit from all `refs/heads/*` references. This might be
+  initially wasteful, but perhaps these objects will become reachable by
+  a later ref update that the client cares about.
+
+* A bundle download during a `git fetch` contains objects already in the
+  object database. This is probably unavoidable if we are using bundles
+  for fetches, since the client will almost always be slightly ahead of
+  the bundle servers after performing its "catch-up" fetch to the remote
+  server. This extra work is most wasteful when the client is fetching
+  much more frequently than the server is computing bundles, such as if
+  the client is using hourly prefetches with background maintenance, but
+  the server is computing bundles weekly. For this reason, the client
+  should not use bundle URIs for fetch unless the server has explicitly
+  recommended it through a `bundle.heuristic` value.
+
+Example Bundle Provider organization
+------------------------------------
+
+The bundle URI feature is intentionally designed to be flexible to
+different ways a bundle provider wants to organize the object data.
+However, it can be helpful to have a complete organization model described
+here so providers can start from that base.
+
+This example organization is a simplified model of what is used by the
+GVFS Cache Servers (see section near the end of this document) which have
+been beneficial in speeding up clones and fetches for very large
+repositories, although using extra software outside of Git.
+
+The bundle provider deploys servers across multiple geographies. Each
+server manages its own bundle set. The server can track a number of Git
+repositories, but provides a bundle list for each based on a pattern. For
+example, when mirroring a repository at `https://<domain>/<org>/<repo>`
+the bundle server could have its bundle list available at
+`https://<server-url>/<domain>/<org>/<repo>`. The origin Git server can
+list all of these servers under the "any" mode:
+
+	[bundle]
+		version = 1
+		mode = any
+
+	[bundle "eastus"]
+		uri = https://eastus.example.com/<domain>/<org>/<repo>
+
+	[bundle "europe"]
+		uri = https://europe.example.com/<domain>/<org>/<repo>
+
+	[bundle "apac"]
+		uri = https://apac.example.com/<domain>/<org>/<repo>
+
+This "list of lists" is static and only changes if a bundle server is
+added or removed.
+
+Each bundle server manages its own set of bundles. The initial bundle list
+contains only a single bundle, containing all of the objects received from
+cloning the repository from the origin server. The list uses the
+`creationToken` heuristic and a `creationToken` is made for the bundle
+based on the server's timestamp.
+
+The bundle server runs regularly-scheduled updates for the bundle list,
+such as once a day. During this task, the server fetches the latest
+contents from the origin server and generates a bundle containing the
+objects reachable from the latest origin refs, but not contained in a
+previously-computed bundle. This bundle is added to the list, with care
+that the `creationToken` is strictly greater than the previous maximum
+`creationToken`.
+
+When the bundle list grows too large, say more than 30 bundles, then the
+oldest "_N_ minus 30" bundles are combined into a single bundle. This
+bundle's `creationToken` is equal to the maximum `creationToken` among the
+merged bundles.
+
+An example bundle list is provided here, although it only has two daily
+bundles and not a full list of 30:
+
+	[bundle]
+		version = 1
+		mode = all
+		heuristic = creationToken
+
+	[bundle "2022-02-13-1644770820-daily"]
+		uri = https://eastus.example.com/<domain>/<org>/<repo>/2022-02-09-1644770820-daily.bundle
+		creationToken = 1644770820
+
+	[bundle "2022-02-09-1644442601-daily"]
+		uri = https://eastus.example.com/<domain>/<org>/<repo>/2022-02-09-1644442601-daily.bundle
+		creationToken = 1644442601
+
+	[bundle "2022-02-02-1643842562"]
+		uri = https://eastus.example.com/<domain>/<org>/<repo>/2022-02-02-1643842562.bundle
+		creationToken = 1643842562
+
+To avoid storing and serving object data in perpetuity despite becoming
+unreachable in the origin server, this bundle merge can be more careful.
+Instead of taking an absolute union of the old bundles, instead the bundle
+can be created by looking at the newer bundles and ensuring that their
+necessary commits are all available in this merged bundle (or in another
+one of the newer bundles). This allows "expiring" object data that is not
+being used by new commits in this window of time. That data could be
+reintroduced by a later push.
+
+The intention of this data organization has two main goals. First, initial
+clones of the repository become faster by downloading precomputed object
+data from a closer source. Second, `git fetch` commands can be faster,
+especially if the client has not fetched for a few days. However, if a
+client does not fetch for 30 days, then the bundle list organization would
+cause redownloading a large amount of object data.
+
+One way to make this organization more useful to users who fetch frequently
+is to have more frequent bundle creation. For example, bundles could be
+created every hour, and then once a day those "hourly" bundles could be
+merged into a "daily" bundle. The daily bundles are merged into the
+oldest bundle after 30 days.
+
+It is recommened that this bundle strategy is repeated with the `blob:none`
+filter if clients of this repository are expecting to use blobless partial
+clones. This list of blobless bundles stays in the same list as the full
+bundles, but uses the `bundle.<id>.filter` key to separate the two groups.
+For very large repositories, the bundle provider may want to _only_ provide
+blobless bundles.
+
+Implementation Plan
+-------------------
+
+This design document is being submitted on its own as an aspirational
+document, with the goal of implementing all of the mentioned client
+features over the course of several patch series. Here is a potential
+outline for submitting these features:
+
+1. Integrate bundle URIs into `git clone` with a `--bundle-uri` option.
+   This will include a new `git fetch --bundle-uri` mode for use as the
+   implementation underneath `git clone`. The initial version here will
+   expect a single bundle at the given URI.
+
+2. Implement the ability to parse a bundle list from a bundle URI and
+   update the `git fetch --bundle-uri` logic to properly distinguish
+   between `bundle.mode` options. Specifically design the feature so
+   that the config format parsing feeds a list of key-value pairs into the
+   bundle list logic.
+
+3. Create the `bundle-uri` protocol v2 command so Git servers can advertise
+   bundle URIs using the key-value pairs. Plug into the existing key-value
+   input to the bundle list logic. Allow `git clone` to discover these
+   bundle URIs and bootstrap the client repository from the bundle data.
+   (This choice is an opt-in via a config option and a command-line
+   option.)
+
+4. Allow the client to understand the `bundle.flag=forFetch` configuration
+   and the `bundle.<id>.creationToken` heuristic. When `git clone`
+   discovers a bundle URI with `bundle.flag=forFetch`, it configures the
+   client repository to check that bundle URI during later `git fetch <remote>`
+   commands.
+
+5. Allow clients to discover bundle URIs during `git fetch` and configure
+   a bundle URI for later fetches if `bundle.flag=forFetch`.
+
+6. Implement the "inspect headers" heuristic to reduce data downloads when
+   the `bundle.<id>.creationToken` heuristic is not available.
+
+As these features are reviewed, this plan might be updated. We also expect
+that new designs will be discovered and implemented as this feature
+matures and becomes used in real-world scenarios.
+
+Related Work: Packfile URIs
+---------------------------
+
+The Git protocol already has a capability where the Git server can list
+a set of URLs along with the packfile response when serving a client
+request. The client is then expected to download the packfiles at those
+locations in order to have a complete understanding of the response.
+
+This mechanism is used by the Gerrit server (implemented with JGit) and
+has been effective at reducing CPU load and improving user performance for
+clones.
+
+A major downside to this mechanism is that the origin server needs to know
+_exactly_ what is in those packfiles, and the packfiles need to be available
+to the user for some time after the server has responded. This coupling
+between the origin and the packfile data is difficult to manage.
+
+Further, this implementation is extremely hard to make work with fetches.
+
+Related Work: GVFS Cache Servers
+--------------------------------
+
+The GVFS Protocol [2] is a set of HTTP endpoints designed independently of
+the Git project before Git's partial clone was created. One feature of this
+protocol is the idea of a "cache server" which can be colocated with build
+machines or developer offices to transfer Git data without overloading the
+central server.
+
+The endpoint that VFS for Git is famous for is the `GET /gvfs/objects/{oid}`
+endpoint, which allows downloading an object on-demand. This is a critical
+piece of the filesystem virtualization of that product.
+
+However, a more subtle need is the `GET /gvfs/prefetch?lastPackTimestamp=<t>`
+endpoint. Given an optional timestamp, the cache server responds with a list
+of precomputed packfiles containing the commits and trees that were introduced
+in those time intervals.
+
+The cache server computes these "prefetch" packfiles using the following
+strategy:
+
+1. Every hour, an "hourly" pack is generated with a given timestamp.
+2. Nightly, the previous 24 hourly packs are rolled up into a "daily" pack.
+3. Nightly, all prefetch packs more than 30 days old are rolled up into
+   one pack.
+
+When a user runs `gvfs clone` or `scalar clone` against a repo with cache
+servers, the client requests all prefetch packfiles, which is at most
+`24 + 30 + 1` packfiles downloading only commits and trees. The client
+then follows with a request to the origin server for the references, and
+attempts to checkout that tip reference. (There is an extra endpoint that
+helps get all reachable trees from a given commit, in case that commit
+was not already in a prefetch packfile.)
+
+During a `git fetch`, a hook requests the prefetch endpoint using the
+most-recent timestamp from a previously-downloaded prefetch packfile.
+Only the list of packfiles with later timestamps are downloaded. Most
+users fetch hourly, so they get at most one hourly prefetch pack. Users
+whose machines have been off or otherwise have not fetched in over 30 days
+might redownload all prefetch packfiles. This is rare.
+
+It is important to note that the clients always contact the origin server
+for the refs advertisement, so the refs are frequently "ahead" of the
+prefetched pack data. The missing objects are downloaded on-demand using
+the `GET gvfs/objects/{oid}` requests, when needed by a command such as
+`git checkout` or `git log`. Some Git optimizations disable checks that
+would cause these on-demand downloads to be too aggressive.
+
+See Also
+--------
+
+[1] https://lore.kernel.org/git/RFC-cover-00.13-0000000000-20210805T150534Z-avarab@gmail.com/
+    An earlier RFC for a bundle URI feature.
+
+[2] https://github.com/microsoft/VFSForGit/blob/master/Protocol.md
+    The GVFS Protocol
diff --git a/Documentation/technical/cruft-packs.txt b/Documentation/technical/cruft-packs.txt
deleted file mode 100644
index d81f3a8..0000000
--- a/Documentation/technical/cruft-packs.txt
+++ /dev/null
@@ -1,123 +0,0 @@
-= Cruft packs
-
-The cruft packs feature offer an alternative to Git's traditional mechanism of
-removing unreachable objects. This document provides an overview of Git's
-pruning mechanism, and how a cruft pack can be used instead to accomplish the
-same.
-
-== Background
-
-To remove unreachable objects from your repository, Git offers `git repack -Ad`
-(see linkgit:git-repack[1]). Quoting from the documentation:
-
-[quote]
-[...] unreachable objects in a previous pack become loose, unpacked objects,
-instead of being left in the old pack. [...] loose unreachable objects will be
-pruned according to normal expiry rules with the next 'git gc' invocation.
-
-Unreachable objects aren't removed immediately, since doing so could race with
-an incoming push which may reference an object which is about to be deleted.
-Instead, those unreachable objects are stored as loose objects and stay that way
-until they are older than the expiration window, at which point they are removed
-by linkgit:git-prune[1].
-
-Git must store these unreachable objects loose in order to keep track of their
-per-object mtimes. If these unreachable objects were written into one big pack,
-then either freshening that pack (because an object contained within it was
-re-written) or creating a new pack of unreachable objects would cause the pack's
-mtime to get updated, and the objects within it would never leave the expiration
-window. Instead, objects are stored loose in order to keep track of the
-individual object mtimes and avoid a situation where all cruft objects are
-freshened at once.
-
-This can lead to undesirable situations when a repository contains many
-unreachable objects which have not yet left the grace period. Having large
-directories in the shards of `.git/objects` can lead to decreased performance in
-the repository. But given enough unreachable objects, this can lead to inode
-starvation and degrade the performance of the whole system. Since we
-can never pack those objects, these repositories often take up a large amount of
-disk space, since we can only zlib compress them, but not store them in delta
-chains.
-
-== Cruft packs
-
-A cruft pack eliminates the need for storing unreachable objects in a loose
-state by including the per-object mtimes in a separate file alongside a single
-pack containing all loose objects.
-
-A cruft pack is written by `git repack --cruft` when generating a new pack.
-linkgit:git-pack-objects[1]'s `--cruft` option. Note that `git repack --cruft`
-is a classic all-into-one repack, meaning that everything in the resulting pack is
-reachable, and everything else is unreachable. Once written, the `--cruft`
-option instructs `git repack` to generate another pack containing only objects
-not packed in the previous step (which equates to packing all unreachable
-objects together). This progresses as follows:
-
-  1. Enumerate every object, marking any object which is (a) not contained in a
-     kept-pack, and (b) whose mtime is within the grace period as a traversal
-     tip.
-
-  2. Perform a reachability traversal based on the tips gathered in the previous
-     step, adding every object along the way to the pack.
-
-  3. Write the pack out, along with a `.mtimes` file that records the per-object
-     timestamps.
-
-This mode is invoked internally by linkgit:git-repack[1] when instructed to
-write a cruft pack. Crucially, the set of in-core kept packs is exactly the set
-of packs which will not be deleted by the repack; in other words, they contain
-all of the repository's reachable objects.
-
-When a repository already has a cruft pack, `git repack --cruft` typically only
-adds objects to it. An exception to this is when `git repack` is given the
-`--cruft-expiration` option, which allows the generated cruft pack to omit
-expired objects instead of waiting for linkgit:git-gc[1] to expire those objects
-later on.
-
-It is linkgit:git-gc[1] that is typically responsible for removing expired
-unreachable objects.
-
-== Caution for mixed-version environments
-
-Repositories that have cruft packs in them will continue to work with any older
-version of Git. Note, however, that previous versions of Git which do not
-understand the `.mtimes` file will use the cruft pack's mtime as the mtime for
-all of the objects in it. In other words, do not expect older (pre-cruft pack)
-versions of Git to interpret or even read the contents of the `.mtimes` file.
-
-Note that having mixed versions of Git GC-ing the same repository can lead to
-unreachable objects never being completely pruned. This can happen under the
-following circumstances:
-
-  - An older version of Git running GC explodes the contents of an existing
-    cruft pack loose, using the cruft pack's mtime.
-  - A newer version running GC collects those loose objects into a cruft pack,
-    where the .mtime file reflects the loose object's actual mtimes, but the
-    cruft pack mtime is "now".
-
-Repeating this process will lead to unreachable objects not getting pruned as a
-result of repeatedly resetting the objects' mtimes to the present time.
-
-If you are GC-ing repositories in a mixed version environment, consider omitting
-the `--cruft` option when using linkgit:git-repack[1] and linkgit:git-gc[1], and
-leaving the `gc.cruftPacks` configuration unset until all writers understand
-cruft packs.
-
-== Alternatives
-
-Notable alternatives to this design include:
-
-  - The location of the per-object mtime data, and
-  - Storing unreachable objects in multiple cruft packs.
-
-On the location of mtime data, a new auxiliary file tied to the pack was chosen
-to avoid complicating the `.idx` format. If the `.idx` format were ever to gain
-support for optional chunks of data, it may make sense to consolidate the
-`.mtimes` format into the `.idx` itself.
-
-Storing unreachable objects among multiple cruft packs (e.g., creating a new
-cruft pack during each repacking operation including only unreachable objects
-which aren't already stored in an earlier cruft pack) is significantly more
-complicated to construct, and so aren't pursued here. The obvious drawback to
-the current implementation is that the entire cruft pack must be re-written from
-scratch.
diff --git a/Documentation/technical/hash-function-transition.txt b/Documentation/technical/hash-function-transition.txt
index 260224b..e2ac36d 100644
--- a/Documentation/technical/hash-function-transition.txt
+++ b/Documentation/technical/hash-function-transition.txt
@@ -205,7 +205,7 @@
 Object storage
 ~~~~~~~~~~~~~~
 Loose objects use zlib compression and packed objects use the packed
-format described in Documentation/technical/pack-format.txt, just like
+format described in linkgit:gitformat-pack[5], just like
 today. The content that is compressed and stored uses SHA-256 content
 instead of SHA-1 content.
 
diff --git a/Documentation/technical/long-running-process-protocol.txt b/Documentation/technical/long-running-process-protocol.txt
index aa0aa9a..6f33654 100644
--- a/Documentation/technical/long-running-process-protocol.txt
+++ b/Documentation/technical/long-running-process-protocol.txt
@@ -3,7 +3,7 @@
 
 This protocol is used when Git needs to communicate with an external
 process throughout the entire life of a single Git command. All
-communication is in pkt-line format (see technical/protocol-common.txt)
+communication is in pkt-line format (see linkgit:gitprotocol-common[5])
 over standard input and standard output.
 
 Handshake
diff --git a/Documentation/technical/packfile-uri.txt b/Documentation/technical/packfile-uri.txt
index 1eb525f..9d453d4 100644
--- a/Documentation/technical/packfile-uri.txt
+++ b/Documentation/technical/packfile-uri.txt
@@ -18,7 +18,7 @@
 directly before the `packfile` section (right after `wanted-refs` if it is
 sent) containing URIs of any of the given protocols. The URIs point to
 packfiles that use only features that the client has declared that it supports
-(e.g. ofs-delta and thin-pack). See protocol-v2.txt for the documentation of
+(e.g. ofs-delta and thin-pack). See linkgit:gitprotocol-v2[5] for the documentation of
 this section.
 
 Clients should then download and index all the given URIs (in addition to
diff --git a/Documentation/technical/partial-clone.txt b/Documentation/technical/partial-clone.txt
index 99f0eb3..92fcee2 100644
--- a/Documentation/technical/partial-clone.txt
+++ b/Documentation/technical/partial-clone.txt
@@ -79,7 +79,7 @@
   upload-pack negotiation.
 +
 This uses the existing capability discovery mechanism.
-See "filter" in Documentation/technical/pack-protocol.txt.
+See "filter" in linkgit:gitprotocol-pack[5].
 
 - Clients pass a "filter-spec" to clone and fetch which is passed to the
   server to request filtering during packfile construction.
diff --git a/Documentation/technical/remembering-renames.txt b/Documentation/technical/remembering-renames.txt
index 2fd5cc8..af091a7 100644
--- a/Documentation/technical/remembering-renames.txt
+++ b/Documentation/technical/remembering-renames.txt
@@ -20,7 +20,7 @@
   3. Why any rename on MERGE_SIDE1 in any given pick is _almost_ always also
      a rename on MERGE_SIDE1 for the next pick
 
-  4. A detailed description of the the counter-examples to #3.
+  4. A detailed description of the counter-examples to #3.
 
   5. Why the special cases in #4 are still fully reasonable to use to pair
      up files for three-way content merging in the merge machinery, and why
diff --git a/Documentation/technical/scalar.txt b/Documentation/technical/scalar.txt
new file mode 100644
index 0000000..0600150
--- /dev/null
+++ b/Documentation/technical/scalar.txt
@@ -0,0 +1,127 @@
+Scalar
+======
+
+Scalar is a repository management tool that optimizes Git for use in large
+repositories. It accomplishes this by helping users to take advantage of
+advanced performance features in Git. Unlike most other Git built-in commands,
+Scalar is not executed as a subcommand of 'git'; rather, it is built as a
+separate executable containing its own series of subcommands.
+
+Background
+----------
+
+Scalar was originally designed as an add-on to Git and implemented as a .NET
+Core application. It was created based on the learnings from the VFS for Git
+project (another application aimed at improving the experience of working with
+large repositories). As part of its initial implementation, Scalar relied on
+custom features in the Microsoft fork of Git that have since been integrated
+into core Git:
+
+* partial clone,
+* commit graphs,
+* multi-pack index,
+* sparse checkout (cone mode),
+* scheduled background maintenance,
+* etc
+
+With the requisite Git functionality in place and a desire to bring the benefits
+of Scalar to the larger Git community, the Scalar application itself was ported
+from C# to C and integrated upstream.
+
+Features
+--------
+
+Scalar is comprised of two major pieces of functionality: automatically
+configuring built-in Git performance features and managing repository
+enlistments.
+
+The Git performance features configured by Scalar (see "Background" for
+examples) confer substantial performance benefits to large repositories, but are
+either too experimental to enable for all of Git yet, or only benefit large
+repositories. As new features are introduced, Scalar should be updated
+accordingly to incorporate them. This will prevent the tool from becoming stale
+while also providing a path for more easily bringing features to the appropriate
+users.
+
+Enlistments are how Scalar knows which repositories on a user's system should
+utilize Scalar-configured features. This allows it to update performance
+settings when new ones are added to the tool, as well as centrally manage
+repository maintenance. The enlistment structure - a root directory with a
+`src/` subdirectory containing the cloned repository itself - is designed to
+encourage users to route build outputs outside of the repository to avoid the
+performance-limiting overhead of ignoring those files in Git.
+
+Design
+------
+
+Scalar is implemented in C and interacts with Git via a mix of child process
+invocations of Git and direct usage of `libgit.a`. Internally, it is structured
+much like other built-ins with subcommands (e.g., `git stash`), containing a
+`cmd_<subcommand>()` function for each subcommand, routed through a `cmd_main()`
+function. Most options are unique to each subcommand, with `scalar` respecting
+some "global" `git` options (e.g., `-c` and `-C`).
+
+Because `scalar` is not invoked as a Git subcommand (like `git scalar`), it is
+built and installed as its own executable in the `bin/` directory, alongside
+`git`, `git-gui`, etc.
+
+Roadmap
+-------
+
+NOTE: this section will be removed once the remaining tasks outlined in this
+roadmap are complete.
+
+Scalar is a large enough project that it is being upstreamed incrementally,
+living in `contrib/` until it is feature-complete. So far, the following patch
+series have been accepted:
+
+- `scalar-the-beginning`: The initial patch series which sets up
+  `contrib/scalar/` and populates it with a minimal `scalar` command that
+  demonstrates the fundamental ideas.
+
+- `scalar-c-and-C`: The `scalar` command learns about two options that can be
+  specified before the command, `-c <key>=<value>` and `-C <directory>`.
+
+- `scalar-diagnose`: The `scalar` command is taught the `diagnose` subcommand.
+
+- `scalar-generalize-diagnose`: Move the functionality of `scalar diagnose`
+  into `git diagnose` and `git bugreport --diagnose`.
+
+- 'scalar-add-fsmonitor: Enable the built-in FSMonitor in Scalar
+  enlistments. At the end of this series, Scalar should be feature-complete
+  from the perspective of a user.
+
+Roughly speaking (and subject to change), the following series are needed to
+"finish" this initial version of Scalar:
+
+- Move Scalar to toplevel: Move Scalar out of `contrib/` and into the root of
+  `git`. This includes a variety of related updates, including:
+    - building & installing Scalar in the Git root-level 'make [install]'.
+    - builing & testing Scalar as part of CI.
+    - moving and expanding test coverage of Scalar (including perf tests).
+    - implementing 'scalar help'/'git help scalar' to display scalar
+      documentation.
+
+Finally, there are two additional patch series that exist in Microsoft's fork of
+Git, but there is no current plan to upstream them. There are some interesting
+ideas there, but the implementation is too specific to Azure Repos and/or VFS
+for Git to be of much help in general.
+
+These still exist mainly because the GVFS protocol is what Azure Repos has
+instead of partial clone, while Git is focused on improving partial clone:
+
+- `scalar-with-gvfs`: The primary purpose of this patch series is to support
+  existing Scalar users whose repositories are hosted in Azure Repos (which does
+  not support Git's partial clones, but supports its predecessor, the GVFS
+  protocol, which is used by Scalar to emulate the partial clone).
+
+  Since the GVFS protocol will never be supported by core Git, this patch series
+  will remain in Microsoft's fork of Git.
+
+- `run-scalar-functional-tests`: The Scalar project developed a quite
+  comprehensive set of integration tests (or, "Functional Tests"). They are the
+  sole remaining part of the original C#-based Scalar project, and this patch
+  adds a GitHub workflow that runs them all.
+
+  Since the tests partially depend on features that are only provided in the
+  `scalar-with-gvfs` patch series, this patch cannot be upstreamed.
diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt
index 865074b..ca9decd 100644
--- a/Documentation/user-manual.txt
+++ b/Documentation/user-manual.txt
@@ -3133,7 +3133,7 @@
 You can save space and make Git faster by moving these loose objects in
 to a "pack file", which stores a group of objects in an efficient
 compressed format; the details of how pack files are formatted can be
-found in link:technical/pack-format.html[pack format].
+found in link:gitformat-pack[5].
 
 To put the loose objects into a pack, just run git repack:
 
diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index fb16249..6ec9e34 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 GVF=GIT-VERSION-FILE
-DEF_VER=v2.37.3
+DEF_VER=v2.37.GIT
 
 LF='
 '
diff --git a/INSTALL b/INSTALL
index 4140a3f..89b15d7 100644
--- a/INSTALL
+++ b/INSTALL
@@ -135,8 +135,7 @@
 
 	  By default, git uses OpenSSL for SHA1 but it will use its own
 	  library (inspired by Mozilla's) with either NO_OPENSSL or
-	  BLK_SHA1.  Also included is a version optimized for PowerPC
-	  (PPC_SHA1).
+	  BLK_SHA1.
 
 	- "libcurl" library is used for fetching and pushing
 	  repositories over http:// or https://, as well as by
diff --git a/Makefile b/Makefile
index 04d0fd1..d9247ea 100644
--- a/Makefile
+++ b/Makefile
@@ -155,9 +155,6 @@
 # Define BLK_SHA1 environment variable to make use of the bundled
 # optimized C SHA1 routine.
 #
-# Define PPC_SHA1 environment variable when running make to make use of
-# a bundled SHA1 routine optimized for PowerPC.
-#
 # Define DC_SHA1 to unconditionally enable the collision-detecting sha1
 # algorithm. This is slower, but may detect attempted collision attacks.
 # Takes priority over other *_SHA1 knobs.
@@ -182,6 +179,8 @@
 #
 # Define BLK_SHA256 to use the built-in SHA-256 routines.
 #
+# Define NETTLE_SHA256 to use the SHA-256 routines in libnettle.
+#
 # Define GCRYPT_SHA256 to use the SHA-256 routines in libgcrypt.
 #
 # Define OPENSSL_SHA256 to use the SHA-256 routines in OpenSSL.
@@ -309,6 +308,11 @@
 # distributions that want to use their packaged versions of Perl
 # modules, instead of the fallbacks shipped with Git.
 #
+# Define NO_GITWEB if you do not want to build or install
+# 'gitweb'. Note that defining NO_PERL currently has the same effect
+# on not installing gitweb, but not on whether it's built in the
+# gitweb/ directory.
+#
 # Define PYTHON_PATH to the path of your Python binary (often /usr/bin/python
 # but /usr/bin/python2.7 or /usr/bin/python3 on some platforms).
 #
@@ -544,6 +548,7 @@
 mergetoolsdir = $(gitexecdir)/mergetools
 sharedir = $(prefix)/share
 gitwebdir = $(sharedir)/gitweb
+gitwebstaticdir = $(gitwebdir)/static
 perllibdir = $(sharedir)/perl5
 localedir = $(sharedir)/locale
 template_dir = share/git-core/templates
@@ -562,7 +567,7 @@
 htmldir_relative = $(patsubst $(prefix)/%,%,$(htmldir))
 perllibdir_relative = $(patsubst $(prefix)/%,%,$(perllibdir))
 
-export prefix bindir sharedir sysconfdir gitwebdir perllibdir localedir
+export prefix bindir sharedir sysconfdir perllibdir localedir
 
 # Set our default programs
 CC = cc
@@ -764,6 +769,7 @@
 TEST_BUILTINS_OBJS += test-ref-store.o
 TEST_BUILTINS_OBJS += test-reftable.o
 TEST_BUILTINS_OBJS += test-regex.o
+TEST_BUILTINS_OBJS += test-rot13-filter.o
 TEST_BUILTINS_OBJS += test-repository.o
 TEST_BUILTINS_OBJS += test-revision-walking.o
 TEST_BUILTINS_OBJS += test-run-command.o
@@ -777,6 +783,7 @@
 TEST_BUILTINS_OBJS += test-string-list.o
 TEST_BUILTINS_OBJS += test-submodule-config.o
 TEST_BUILTINS_OBJS += test-submodule-nested-repo-config.o
+TEST_BUILTINS_OBJS += test-submodule.o
 TEST_BUILTINS_OBJS += test-subprocess.o
 TEST_BUILTINS_OBJS += test-trace2.o
 TEST_BUILTINS_OBJS += test-urlmatch-normalization.o
@@ -898,6 +905,7 @@
 LIB_OBJS += bloom.o
 LIB_OBJS += branch.o
 LIB_OBJS += bulk-checkin.o
+LIB_OBJS += bundle-uri.o
 LIB_OBJS += bundle.o
 LIB_OBJS += cache-tree.o
 LIB_OBJS += cbtree.o
@@ -910,6 +918,7 @@
 LIB_OBJS += commit-graph.o
 LIB_OBJS += commit-reach.o
 LIB_OBJS += commit.o
+LIB_OBJS += compat/nonblock.o
 LIB_OBJS += compat/obstack.o
 LIB_OBJS += compat/terminal.o
 LIB_OBJS += compat/zlib-uncompress2.o
@@ -924,6 +933,7 @@
 LIB_OBJS += date.o
 LIB_OBJS += decorate.o
 LIB_OBJS += delta-islands.o
+LIB_OBJS += diagnose.o
 LIB_OBJS += diff-delta.o
 LIB_OBJS += diff-merges.o
 LIB_OBJS += diff-lib.o
@@ -984,7 +994,6 @@
 LIB_OBJS += merge-ort-wrappers.o
 LIB_OBJS += merge-recursive.o
 LIB_OBJS += merge.o
-LIB_OBJS += mergesort.o
 LIB_OBJS += midx.o
 LIB_OBJS += name-hash.o
 LIB_OBJS += negotiator/default.o
@@ -1145,6 +1154,7 @@
 BUILTIN_OBJS += builtin/credential-store.o
 BUILTIN_OBJS += builtin/credential.o
 BUILTIN_OBJS += builtin/describe.o
+BUILTIN_OBJS += builtin/diagnose.o
 BUILTIN_OBJS += builtin/diff-files.o
 BUILTIN_OBJS += builtin/diff-index.o
 BUILTIN_OBJS += builtin/diff-tree.o
@@ -1286,7 +1296,7 @@
 # For the 'coccicheck' target; setting SPATCH_BATCH_SIZE higher will
 # usually result in less CPU usage at the cost of higher peak memory.
 # Setting it to 0 will feed all files in a single spatch invocation.
-SPATCH_FLAGS = --all-includes --patch .
+SPATCH_FLAGS = --all-includes
 SPATCH_BATCH_SIZE = 1
 
 include config.mak.uname
@@ -1791,6 +1801,10 @@
 	SHA1_MAX_BLOCK_SIZE = 1024L*1024L*1024L
 endif
 
+ifdef PPC_SHA1
+$(error the PPC_SHA1 flag has been removed along with the PowerPC-specific SHA-1 implementation.)
+endif
+
 ifdef OPENSSL_SHA1
 	EXTLIBS += $(LIB_4_CRYPTO)
 	BASIC_CFLAGS += -DSHA1_OPENSSL
@@ -1799,10 +1813,6 @@
 	LIB_OBJS += block-sha1/sha1.o
 	BASIC_CFLAGS += -DSHA1_BLK
 else
-ifdef PPC_SHA1
-	LIB_OBJS += ppc/sha1.o ppc/sha1ppc.o
-	BASIC_CFLAGS += -DSHA1_PPC
-else
 ifdef APPLE_COMMON_CRYPTO
 	COMPAT_CFLAGS += -DCOMMON_DIGEST_FOR_OPENSSL
 	BASIC_CFLAGS += -DSHA1_APPLE
@@ -1836,12 +1846,15 @@
 endif
 endif
 endif
-endif
 
 ifdef OPENSSL_SHA256
 	EXTLIBS += $(LIB_4_CRYPTO)
 	BASIC_CFLAGS += -DSHA256_OPENSSL
 else
+ifdef NETTLE_SHA256
+	BASIC_CFLAGS += -DSHA256_NETTLE
+	EXTLIBS += -lnettle
+else
 ifdef GCRYPT_SHA256
 	BASIC_CFLAGS += -DSHA256_GCRYPT
 	EXTLIBS += -lgcrypt
@@ -1850,6 +1863,7 @@
 	BASIC_CFLAGS += -DSHA256_BLK
 endif
 endif
+endif
 
 ifdef SHA1_MAX_BLOCK_SIZE
 	LIB_OBJS += compat/sha1-chunked.o
@@ -2089,6 +2103,7 @@
 prefix_SQ = $(subst ','\'',$(prefix))
 perllibdir_relative_SQ = $(subst ','\'',$(perllibdir_relative))
 gitwebdir_SQ = $(subst ','\'',$(gitwebdir))
+gitwebstaticdir_SQ = $(subst ','\'',$(gitwebstaticdir))
 
 SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))
 TEST_SHELL_PATH_SQ = $(subst ','\'',$(TEST_SHELL_PATH))
@@ -2417,10 +2432,6 @@
 perllibdir:
 	@echo '$(perllibdir_SQ)'
 
-.PHONY: gitweb
-gitweb:
-	$(QUIET_SUBDIR0)gitweb $(QUIET_SUBDIR1) all
-
 git-instaweb: git-instaweb.sh GIT-SCRIPT-DEFINES
 	$(QUIET_GEN)$(cmd_munge_script) && \
 	chmod +x $@+ && \
@@ -2581,13 +2592,7 @@
 compdb_args =
 endif
 
-ASM_SRC := $(wildcard $(OBJECTS:o=S))
-ASM_OBJ := $(ASM_SRC:S=o)
-C_OBJ := $(filter-out $(ASM_OBJ),$(OBJECTS))
-
-$(C_OBJ): %.o: %.c GIT-CFLAGS $(missing_dep_dirs) $(missing_compdb_dir)
-	$(QUIET_CC)$(CC) -o $*.o -c $(dep_args) $(compdb_args) $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) $<
-$(ASM_OBJ): %.o: %.S GIT-CFLAGS $(missing_dep_dirs) $(missing_compdb_dir)
+$(OBJECTS): %.o: %.c GIT-CFLAGS $(missing_dep_dirs) $(missing_compdb_dir)
 	$(QUIET_CC)$(CC) -o $*.o -c $(dep_args) $(compdb_args) $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) $<
 
 %.s: %.c GIT-CFLAGS FORCE
@@ -3079,7 +3084,7 @@
 check-sha1:: t/helper/test-tool$X
 	t/helper/test-sha1.sh
 
-SP_OBJ = $(patsubst %.o,%.sp,$(C_OBJ))
+SP_OBJ = $(patsubst %.o,%.sp,$(OBJECTS))
 
 $(SP_OBJ): %.sp: %.c %.o
 	$(QUIET_SP)cgcc -no-compile $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) \
@@ -3091,6 +3096,9 @@
 sparse: $(SP_OBJ)
 
 EXCEPT_HDRS := $(GENERATED_H) unicode-width.h compat/% xdiff/%
+ifndef NETTLE_SHA256
+	EXCEPT_HDRS += sha256/nettle.h
+endif
 ifndef GCRYPT_SHA256
 	EXCEPT_HDRS += sha256/gcrypt.h
 endif
@@ -3123,6 +3131,8 @@
 		exit 1; \
 	fi
 
+COCCI_TEST_RES = $(wildcard contrib/coccinelle/tests/*.res)
+
 %.cocci.patch: %.cocci $(COCCI_SOURCES)
 	$(QUIET_SPATCH) \
 	if test $(SPATCH_BATCH_SIZE) = 0; then \
@@ -3131,7 +3141,8 @@
 		limit='-n $(SPATCH_BATCH_SIZE)'; \
 	fi; \
 	if ! echo $(COCCI_SOURCES) | xargs $$limit \
-		$(SPATCH) --sp-file $< $(SPATCH_FLAGS) \
+		$(SPATCH) $(SPATCH_FLAGS) \
+		--sp-file $< --patch . \
 		>$@+ 2>$@.log; \
 	then \
 		cat $@.log; \
@@ -3142,13 +3153,43 @@
 	then \
 		echo '    ' SPATCH result: $@; \
 	fi
+
+COCCI_TEST_RES_GEN = $(addprefix .build/,$(COCCI_TEST_RES))
+$(COCCI_TEST_RES_GEN): .build/%.res : %.c
+$(COCCI_TEST_RES_GEN): .build/%.res : %.res
+$(COCCI_TEST_RES_GEN): .build/contrib/coccinelle/tests/%.res : contrib/coccinelle/%.cocci
+	$(call mkdir_p_parent_template)
+	$(QUIET_SPATCH_T)$(SPATCH) $(SPATCH_FLAGS) \
+		--very-quiet --no-show-diff \
+		--sp-file $< -o $@ \
+		$(@:.build/%.res=%.c) && \
+	cmp $(@:.build/%=%) $@ || \
+	git -P diff --no-index $(@:.build/%=%) $@ 2>/dev/null; \
+
+.PHONY: coccicheck-test
+coccicheck-test: $(COCCI_TEST_RES_GEN)
+
+coccicheck: coccicheck-test
 coccicheck: $(addsuffix .patch,$(filter-out %.pending.cocci,$(wildcard contrib/coccinelle/*.cocci)))
 
 # See contrib/coccinelle/README
+coccicheck-pending: coccicheck-test
 coccicheck-pending: $(addsuffix .patch,$(wildcard contrib/coccinelle/*.pending.cocci))
 
 .PHONY: coccicheck coccicheck-pending
 
+# "Sub"-Makefiles, not really because they can't be run stand-alone,
+# only there to contain directory-specific rules and variables
+## gitweb/Makefile inclusion:
+MAK_DIR_GITWEB = gitweb/
+include gitweb/Makefile
+
+.PHONY: gitweb
+gitweb: $(MAK_DIR_GITWEB_ALL)
+ifndef NO_GITWEB
+all:: gitweb
+endif
+
 ### Installation rules
 
 ifneq ($(filter /%,$(firstword $(template_dir))),)
@@ -3221,7 +3262,6 @@
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(perllibdir_SQ)'
 	(cd perl/build/lib && $(TAR) cf - .) | \
 	(cd '$(DESTDIR_SQ)$(perllibdir_SQ)' && umask 022 && $(TAR) xof -)
-	$(MAKE) -C gitweb install
 endif
 ifndef NO_TCLTK
 	$(MAKE) -C gitk-git install
@@ -3276,10 +3316,8 @@
 		  cp "$$execdir/git-remote-http$X" "$$execdir/$$p" || exit; } \
 	done
 
-.PHONY: install-gitweb install-doc install-man install-man-perl install-html install-info install-pdf
+.PHONY: install-doc install-man install-man-perl install-html install-info install-pdf
 .PHONY: quick-install-doc quick-install-man quick-install-html
-install-gitweb:
-	$(MAKE) -C gitweb install
 
 install-doc: install-man-perl
 	$(MAKE) -C Documentation install
@@ -3403,12 +3441,13 @@
 	$(RM) $(addsuffix *.gcno,$(addprefix $(PROFILE_DIR)/, $(object_dirs)))
 
 cocciclean:
+	$(RM) -r .build/contrib/coccinelle
 	$(RM) contrib/coccinelle/*.cocci.patch*
 
 clean: profile-clean coverage-clean cocciclean
 	$(RM) -r .build
 	$(RM) po/git.pot po/git-core.pot
-	$(RM) *.res
+	$(RM) git.res
 	$(RM) $(OBJECTS)
 	$(RM) $(LIB_FILE) $(XDIFF_LIB) $(REFTABLE_LIB) $(REFTABLE_TEST_LIB)
 	$(RM) $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) git$X
@@ -3425,7 +3464,6 @@
 	$(MAKE) -C Documentation/ clean
 	$(RM) Documentation/GIT-EXCLUDED-PROGRAMS
 ifndef NO_PERL
-	$(MAKE) -C gitweb clean
 	$(RM) -r perl/build/
 endif
 	$(MAKE) -C templates/ clean
@@ -3489,6 +3527,7 @@
 		sed -e '1,/^### command list/d' \
 		    -e '/^#/d' \
 		    -e '/guide$$/d' \
+		    -e '/interfaces$$/d' \
 		    -e 's/[ 	].*//' \
 		    -e 's/^/listed /' command-list.txt; \
 		$(MAKE) -C Documentation print-man1 | \
diff --git a/RelNotes b/RelNotes
index 6d88c2c..d505db6 120000
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/2.37.3.txt
\ No newline at end of file
+Documentation/RelNotes/2.38.0.txt
\ No newline at end of file
diff --git a/add-interactive.c b/add-interactive.c
index 22fcd34..f071b2a 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -430,7 +430,7 @@
 	struct file_item *item;
 };
 
-static int pathname_entry_cmp(const void *unused_cmp_data,
+static int pathname_entry_cmp(const void *cmp_data UNUSED,
 			      const struct hashmap_entry *he1,
 			      const struct hashmap_entry *he2,
 			      const void *name)
diff --git a/add-patch.c b/add-patch.c
index 509ca04..33ecd83 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -191,10 +191,10 @@
 	.apply_check_args = { "-R", NULL },
 	.is_reverse = 1,
 	.prompt_mode = {
-		N_("Discard mode change from index and worktree [y,n,q,a,d%s,?]? "),
-		N_("Discard deletion from index and worktree [y,n,q,a,d%s,?]? "),
-		N_("Discard addition from index and worktree [y,n,q,a,d%s,?]? "),
-		N_("Discard this hunk from index and worktree [y,n,q,a,d%s,?]? "),
+		N_("Discard mode change from worktree [y,n,q,a,d%s,?]? "),
+		N_("Discard deletion from worktree [y,n,q,a,d%s,?]? "),
+		N_("Discard addition from worktree [y,n,q,a,d%s,?]? "),
+		N_("Discard this hunk from worktree [y,n,q,a,d%s,?]? "),
 	},
 	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
 			     "will immediately be marked for discarding."),
@@ -213,10 +213,10 @@
 	.apply_args = { NULL },
 	.apply_check_args = { NULL },
 	.prompt_mode = {
-		N_("Apply mode change to index and worktree [y,n,q,a,d%s,?]? "),
-		N_("Apply deletion to index and worktree [y,n,q,a,d%s,?]? "),
-		N_("Apply addition to index and worktree [y,n,q,a,d%s,?]? "),
-		N_("Apply this hunk to index and worktree [y,n,q,a,d%s,?]? "),
+		N_("Apply mode change to worktree [y,n,q,a,d%s,?]? "),
+		N_("Apply deletion to worktree [y,n,q,a,d%s,?]? "),
+		N_("Apply addition to worktree [y,n,q,a,d%s,?]? "),
+		N_("Apply this hunk to worktree [y,n,q,a,d%s,?]? "),
 	},
 	.edit_hunk_hint = N_("If the patch applies cleanly, the edited hunk "
 			     "will immediately be marked for applying."),
@@ -238,6 +238,7 @@
 	 * include the newline.
 	 */
 	size_t extra_start, extra_end, colored_extra_start, colored_extra_end;
+	unsigned suppress_colored_line_range:1;
 };
 
 struct hunk {
@@ -358,15 +359,14 @@
 	if (!eol)
 		eol = s->colored.buf + s->colored.len;
 	p = memmem(line, eol - line, "@@ -", 4);
-	if (!p)
-		return error(_("could not parse colored hunk header '%.*s'"),
-			     (int)(eol - line), line);
-	p = memmem(p + 4, eol - p - 4, " @@", 3);
-	if (!p)
-		return error(_("could not parse colored hunk header '%.*s'"),
-			     (int)(eol - line), line);
+	if (p && (p = memmem(p + 4, eol - p - 4, " @@", 3))) {
+		header->colored_extra_start = p + 3 - s->colored.buf;
+	} else {
+		/* could not parse colored hunk header, leave as-is */
+		header->colored_extra_start = hunk->colored_start;
+		header->suppress_colored_line_range = 1;
+	}
 	hunk->colored_start = eol - s->colored.buf + (*eol == '\n');
-	header->colored_extra_start = p + 3 - s->colored.buf;
 	header->colored_extra_end = hunk->colored_start;
 
 	return 0;
@@ -419,7 +419,8 @@
 	}
 	color_arg_index = args.nr;
 	/* Use `--no-color` explicitly, just in case `diff.color = always`. */
-	strvec_pushl(&args, "--no-color", "-p", "--", NULL);
+	strvec_pushl(&args, "--no-color", "--ignore-submodules=dirty", "-p",
+		     "--", NULL);
 	for (i = 0; i < ps->nr; i++)
 		strvec_push(&args, ps->items[i].original);
 
@@ -592,7 +593,10 @@
 			if (colored_eol)
 				colored_p = colored_eol + 1;
 			else if (p != pend)
-				/* colored shorter than non-colored? */
+				/* non-colored has more lines? */
+				goto mismatched_output;
+			else if (colored_p == colored_pend)
+				/* last line has no matching colored one? */
 				goto mismatched_output;
 			else
 				colored_p = colored_pend;
@@ -656,6 +660,15 @@
 		if (!colored) {
 			p = s->plain.buf + header->extra_start;
 			len = header->extra_end - header->extra_start;
+		} else if (header->suppress_colored_line_range) {
+			strbuf_add(out,
+				   s->colored.buf + header->colored_extra_start,
+				   header->colored_extra_end -
+				   header->colored_extra_start);
+
+			strbuf_add(out, s->colored.buf + hunk->colored_start,
+				   hunk->colored_end - hunk->colored_start);
+			return;
 		} else {
 			strbuf_addstr(out, s->s.fraginfo_color);
 			p = s->colored.buf + header->colored_extra_start;
@@ -1547,7 +1560,7 @@
 			strbuf_remove(&s->answer, 0, 1);
 			strbuf_trim(&s->answer);
 			i = hunk_index - DISPLAY_HUNKS_LINES / 2;
-			if (i < file_diff->mode_change)
+			if (i < (int)file_diff->mode_change)
 				i = file_diff->mode_change;
 			while (s->answer.len == 0) {
 				i = display_hunks(s, file_diff, i);
diff --git a/archive-tar.c b/archive-tar.c
index 042feb6..3e4822b 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -38,11 +38,18 @@
 #define USTAR_MAX_MTIME 077777777777ULL
 #endif
 
+static void tar_write_block(const void *buf)
+{
+	write_or_die(1, buf, BLOCKSIZE);
+}
+
+static void (*write_block)(const void *) = tar_write_block;
+
 /* writes out the whole block, but only if it is full */
 static void write_if_needed(void)
 {
 	if (offset == BLOCKSIZE) {
-		write_or_die(1, block, BLOCKSIZE);
+		write_block(block);
 		offset = 0;
 	}
 }
@@ -66,7 +73,7 @@
 		write_if_needed();
 	}
 	while (size >= BLOCKSIZE) {
-		write_or_die(1, buf, BLOCKSIZE);
+		write_block(buf);
 		size -= BLOCKSIZE;
 		buf += BLOCKSIZE;
 	}
@@ -101,10 +108,10 @@
 {
 	int tail = BLOCKSIZE - offset;
 	memset(block + offset, 0, tail);
-	write_or_die(1, block, BLOCKSIZE);
+	write_block(block);
 	if (tail < 2 * RECORDSIZE) {
 		memset(block, 0, offset);
-		write_or_die(1, block, BLOCKSIZE);
+		write_block(block);
 	}
 }
 
@@ -359,7 +366,8 @@
 	return NULL;
 }
 
-static int tar_filter_config(const char *var, const char *value, void *data)
+static int tar_filter_config(const char *var, const char *value,
+			     void *data UNUSED)
 {
 	struct archiver *ar;
 	const char *name;
@@ -383,8 +391,8 @@
 	if (!strcmp(type, "command")) {
 		if (!value)
 			return config_error_nonbool(var);
-		free(ar->data);
-		ar->data = xstrdup(value);
+		free(ar->filter_command);
+		ar->filter_command = xstrdup(value);
 		return 0;
 	}
 	if (!strcmp(type, "remote")) {
@@ -413,7 +421,7 @@
 	return tar_filter_config(var, value, cb);
 }
 
-static int write_tar_archive(const struct archiver *ar,
+static int write_tar_archive(const struct archiver *ar UNUSED,
 			     struct archiver_args *args)
 {
 	int err = 0;
@@ -425,17 +433,65 @@
 	return err;
 }
 
+static git_zstream gzstream;
+static unsigned char outbuf[16384];
+
+static void tgz_deflate(int flush)
+{
+	while (gzstream.avail_in || flush == Z_FINISH) {
+		int status = git_deflate(&gzstream, flush);
+		if (!gzstream.avail_out || status == Z_STREAM_END) {
+			write_or_die(1, outbuf, gzstream.next_out - outbuf);
+			gzstream.next_out = outbuf;
+			gzstream.avail_out = sizeof(outbuf);
+			if (status == Z_STREAM_END)
+				break;
+		}
+		if (status != Z_OK && status != Z_BUF_ERROR)
+			die(_("deflate error (%d)"), status);
+	}
+}
+
+static void tgz_write_block(const void *data)
+{
+	gzstream.next_in = (void *)data;
+	gzstream.avail_in = BLOCKSIZE;
+	tgz_deflate(Z_NO_FLUSH);
+}
+
+static const char internal_gzip_command[] = "git archive gzip";
+
 static int write_tar_filter_archive(const struct archiver *ar,
 				    struct archiver_args *args)
 {
+#if ZLIB_VERNUM >= 0x1221
+	struct gz_header_s gzhead = { .os = 3 }; /* Unix, for reproducibility */
+#endif
 	struct strbuf cmd = STRBUF_INIT;
 	struct child_process filter = CHILD_PROCESS_INIT;
 	int r;
 
-	if (!ar->data)
+	if (!ar->filter_command)
 		BUG("tar-filter archiver called with no filter defined");
 
-	strbuf_addstr(&cmd, ar->data);
+	if (!strcmp(ar->filter_command, internal_gzip_command)) {
+		write_block = tgz_write_block;
+		git_deflate_init_gzip(&gzstream, args->compression_level);
+#if ZLIB_VERNUM >= 0x1221
+		if (deflateSetHeader(&gzstream.z, &gzhead) != Z_OK)
+			BUG("deflateSetHeader() called too late");
+#endif
+		gzstream.next_out = outbuf;
+		gzstream.avail_out = sizeof(outbuf);
+
+		r = write_tar_archive(ar, args);
+
+		tgz_deflate(Z_FINISH);
+		git_deflate_end(&gzstream);
+		return r;
+	}
+
+	strbuf_addstr(&cmd, ar->filter_command);
 	if (args->compression_level >= 0)
 		strbuf_addf(&cmd, " -%d", args->compression_level);
 
@@ -471,14 +527,14 @@
 	int i;
 	register_archiver(&tar_archiver);
 
-	tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
+	tar_filter_config("tar.tgz.command", internal_gzip_command, NULL);
 	tar_filter_config("tar.tgz.remote", "true", NULL);
-	tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
+	tar_filter_config("tar.tar.gz.command", internal_gzip_command, NULL);
 	tar_filter_config("tar.tar.gz.remote", "true", NULL);
 	git_config(git_tar_config, NULL);
 	for (i = 0; i < nr_tar_filters; i++) {
 		/* omit any filters that never had a command configured */
-		if (tar_filters[i]->data)
+		if (tar_filters[i]->filter_command)
 			register_archiver(tar_filters[i]);
 	}
 }
diff --git a/archive-zip.c b/archive-zip.c
index 9fe43d7..0456f1e 100644
--- a/archive-zip.c
+++ b/archive-zip.c
@@ -612,12 +612,13 @@
 	*dos_time = tm.tm_sec / 2 + tm.tm_min * 32 + tm.tm_hour * 2048;
 }
 
-static int archive_zip_config(const char *var, const char *value, void *data)
+static int archive_zip_config(const char *var, const char *value,
+			      void *data UNUSED)
 {
 	return userdiff_config(var, value);
 }
 
-static int write_zip_archive(const struct archiver *ar,
+static int write_zip_archive(const struct archiver *ar UNUSED,
 			     struct archiver_args *args)
 {
 	int err;
diff --git a/archive.c b/archive.c
index d5109ab..61a79e4 100644
--- a/archive.c
+++ b/archive.c
@@ -382,7 +382,8 @@
 	struct archiver_args *args;
 };
 
-static int reject_entry(const struct object_id *oid, struct strbuf *base,
+static int reject_entry(const struct object_id *oid UNUSED,
+			struct strbuf *base,
 			const char *filename, unsigned mode,
 			void *context)
 {
diff --git a/archive.h b/archive.h
index 49fab71..08bed3e 100644
--- a/archive.h
+++ b/archive.h
@@ -43,7 +43,7 @@
 	const char *name;
 	int (*write_archive)(const struct archiver *, struct archiver_args *);
 	unsigned flags;
-	void *data;
+	char *filter_command;
 };
 void register_archiver(struct archiver *);
 
diff --git a/attr.c b/attr.c
index 21e4ad2..8250b06 100644
--- a/attr.c
+++ b/attr.c
@@ -61,10 +61,10 @@
 };
 
 /* attr_hashmap comparison function */
-static int attr_hash_entry_cmp(const void *unused_cmp_data,
+static int attr_hash_entry_cmp(const void *cmp_data UNUSED,
 			       const struct hashmap_entry *eptr,
 			       const struct hashmap_entry *entry_or_key,
-			       const void *unused_keydata)
+			       const void *keydata UNUSED)
 {
 	const struct attr_hash_entry *a, *b;
 
@@ -1023,7 +1023,7 @@
 	}
 	return match_pathname(pathname, pathlen - isdir,
 			      base, baselen,
-			      pattern, prefix, pat->patternlen, pat->flags);
+			      pattern, prefix, pat->patternlen);
 }
 
 static int macroexpand_one(struct all_attrs_item *all_attrs, int nr, int rem);
diff --git a/bisect.c b/bisect.c
index b63669c..fd581b8 100644
--- a/bisect.c
+++ b/bisect.c
@@ -441,7 +441,7 @@
 }
 
 static int register_ref(const char *refname, const struct object_id *oid,
-			int flags, void *cb_data)
+			int flags UNUSED, void *cb_data UNUSED)
 {
 	struct strbuf good_prefix = STRBUF_INIT;
 	strbuf_addstr(&good_prefix, term_good);
@@ -648,11 +648,14 @@
 }
 
 static void bisect_rev_setup(struct repository *r, struct rev_info *revs,
+			     struct strvec *rev_argv,
 			     const char *prefix,
 			     const char *bad_format, const char *good_format,
 			     int read_paths)
 {
-	struct strvec rev_argv = STRVEC_INIT;
+	struct setup_revision_opt opt = {
+		.free_removed_argv_elements = 1,
+	};
 	int i;
 
 	repo_init_revisions(r, revs, prefix);
@@ -660,17 +663,16 @@
 	revs->commit_format = CMIT_FMT_UNSPECIFIED;
 
 	/* rev_argv.argv[0] will be ignored by setup_revisions */
-	strvec_push(&rev_argv, "bisect_rev_setup");
-	strvec_pushf(&rev_argv, bad_format, oid_to_hex(current_bad_oid));
+	strvec_push(rev_argv, "bisect_rev_setup");
+	strvec_pushf(rev_argv, bad_format, oid_to_hex(current_bad_oid));
 	for (i = 0; i < good_revs.nr; i++)
-		strvec_pushf(&rev_argv, good_format,
+		strvec_pushf(rev_argv, good_format,
 			     oid_to_hex(good_revs.oid + i));
-	strvec_push(&rev_argv, "--");
+	strvec_push(rev_argv, "--");
 	if (read_paths)
-		read_bisect_paths(&rev_argv);
+		read_bisect_paths(rev_argv);
 
-	setup_revisions(rev_argv.nr, rev_argv.v, revs, NULL);
-	/* XXX leak rev_argv, as "revs" may still be pointing to it */
+	setup_revisions(rev_argv->nr, rev_argv->v, revs, &opt);
 }
 
 static void bisect_common(struct rev_info *revs)
@@ -873,10 +875,11 @@
 static int check_ancestors(struct repository *r, int rev_nr,
 			   struct commit **rev, const char *prefix)
 {
+	struct strvec rev_argv = STRVEC_INIT;
 	struct rev_info revs;
 	int res;
 
-	bisect_rev_setup(r, &revs, prefix, "^%s", "%s", 0);
+	bisect_rev_setup(r, &revs, &rev_argv, prefix, "^%s", "%s", 0);
 
 	bisect_common(&revs);
 	res = (revs.commits != NULL);
@@ -885,6 +888,7 @@
 	clear_commit_marks_many(rev_nr, rev, ALL_REV_FLAGS);
 
 	release_revisions(&revs);
+	strvec_clear(&rev_argv);
 	return res;
 }
 
@@ -1010,6 +1014,7 @@
  */
 enum bisect_error bisect_next_all(struct repository *r, const char *prefix)
 {
+	struct strvec rev_argv = STRVEC_INIT;
 	struct rev_info revs = REV_INFO_INIT;
 	struct commit_list *tried;
 	int reaches = 0, all = 0, nr, steps;
@@ -1037,7 +1042,7 @@
 	if (res)
 		goto cleanup;
 
-	bisect_rev_setup(r, &revs, prefix, "%s", "^%s", 1);
+	bisect_rev_setup(r, &revs, &rev_argv, prefix, "%s", "^%s", 1);
 
 	revs.first_parent_only = !!(bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY);
 	revs.limited = 1;
@@ -1054,7 +1059,7 @@
 		 */
 		res = error_if_skipped_commits(tried, NULL);
 		if (res < 0)
-			return res;
+			goto cleanup;
 		printf(_("%s was both %s and %s\n"),
 		       oid_to_hex(current_bad_oid),
 		       term_good,
@@ -1112,6 +1117,7 @@
 	res = bisect_checkout(bisect_rev, no_checkout);
 cleanup:
 	release_revisions(&revs);
+	strvec_clear(&rev_argv);
 	return res;
 }
 
@@ -1154,8 +1160,9 @@
 	return (e < 3 * x) ? n : n - 1;
 }
 
-static int mark_for_removal(const char *refname, const struct object_id *oid,
-			    int flag, void *cb_data)
+static int mark_for_removal(const char *refname,
+			    const struct object_id *oid UNUSED,
+			    int flag UNUSED, void *cb_data)
 {
 	struct string_list *refs = cb_data;
 	char *ref = xstrfmt("refs/bisect%s", refname);
diff --git a/blame.c b/blame.c
index da1052a..8bfeaa1 100644
--- a/blame.c
+++ b/blame.c
@@ -1098,30 +1098,22 @@
 	}
 }
 
-static void *get_next_blame(const void *p)
-{
-	return ((struct blame_entry *)p)->next;
-}
-
-static void set_next_blame(void *p1, void *p2)
-{
-	((struct blame_entry *)p1)->next = p2;
-}
+DEFINE_LIST_SORT(static, sort_blame_entries, struct blame_entry, next);
 
 /*
  * Final image line numbers are all different, so we don't need a
  * three-way comparison here.
  */
 
-static int compare_blame_final(const void *p1, const void *p2)
+static int compare_blame_final(const struct blame_entry *e1,
+			       const struct blame_entry *e2)
 {
-	return ((struct blame_entry *)p1)->lno > ((struct blame_entry *)p2)->lno
-		? 1 : -1;
+	return e1->lno > e2->lno ? 1 : -1;
 }
 
-static int compare_blame_suspect(const void *p1, const void *p2)
+static int compare_blame_suspect(const struct blame_entry *s1,
+				 const struct blame_entry *s2)
 {
-	const struct blame_entry *s1 = p1, *s2 = p2;
 	/*
 	 * to allow for collating suspects, we sort according to the
 	 * respective pointer value as the primary sorting criterion.
@@ -1138,8 +1130,7 @@
 
 void blame_sort_final(struct blame_scoreboard *sb)
 {
-	sb->ent = llist_mergesort(sb->ent, get_next_blame, set_next_blame,
-				  compare_blame_final);
+	sort_blame_entries(&sb->ent, compare_blame_final);
 }
 
 static int compare_commits_by_reverse_commit_date(const void *a,
@@ -1964,9 +1955,7 @@
 		    parent, target, 0);
 	*d.dstq = NULL;
 	if (ignore_diffs)
-		newdest = llist_mergesort(newdest, get_next_blame,
-					  set_next_blame,
-					  compare_blame_suspect);
+		sort_blame_entries(&newdest, compare_blame_suspect);
 	queue_blames(sb, parent, newdest);
 
 	return;
@@ -2383,8 +2372,7 @@
  */
 static void distribute_blame(struct blame_scoreboard *sb, struct blame_entry *blamed)
 {
-	blamed = llist_mergesort(blamed, get_next_blame, set_next_blame,
-				 compare_blame_suspect);
+	sort_blame_entries(&blamed, compare_blame_suspect);
 	while (blamed)
 	{
 		struct blame_origin *porigin = blamed->suspect;
diff --git a/block-sha1/sha1.c b/block-sha1/sha1.c
index 5974cd7..80cebd2 100644
--- a/block-sha1/sha1.c
+++ b/block-sha1/sha1.c
@@ -28,10 +28,6 @@
  * try to do the silly "optimize away loads" part because it won't
  * see what the value will be).
  *
- * Ben Herrenschmidt reports that on PPC, the C version comes close
- * to the optimized asm with this (ie on PPC you don't want that
- * 'volatile', since there are lots of registers).
- *
  * On ARM we get the best code generation by forcing a full memory barrier
  * between each SHA_ROUND, otherwise gcc happily get wild with spilling and
  * the stack frame size simply explode and performance goes down the drain.
diff --git a/bloom.c b/bloom.c
index 816f063..d073052 100644
--- a/bloom.c
+++ b/bloom.c
@@ -163,10 +163,10 @@
 	init_bloom_filter_slab(&bloom_filters);
 }
 
-static int pathmap_cmp(const void *hashmap_cmp_fn_data,
+static int pathmap_cmp(const void *hashmap_cmp_fn_data UNUSED,
 		       const struct hashmap_entry *eptr,
 		       const struct hashmap_entry *entry_or_key,
-		       const void *keydata)
+		       const void *keydata UNUSED)
 {
 	const struct pathmap_hash_entry *e1, *e2;
 
diff --git a/branch.c b/branch.c
index 4c8523c..d182756 100644
--- a/branch.c
+++ b/branch.c
@@ -10,6 +10,7 @@
 #include "worktree.h"
 #include "submodule-config.h"
 #include "run-command.h"
+#include "strmap.h"
 
 struct tracking {
 	struct refspec_item spec;
@@ -369,6 +370,83 @@
 	return ref_exists(ref->buf);
 }
 
+static int initialized_checked_out_branches;
+static struct strmap current_checked_out_branches = STRMAP_INIT;
+
+static void prepare_checked_out_branches(void)
+{
+	int i = 0;
+	struct worktree **worktrees;
+
+	if (initialized_checked_out_branches)
+		return;
+	initialized_checked_out_branches = 1;
+
+	worktrees = get_worktrees();
+
+	while (worktrees[i]) {
+		char *old;
+		struct wt_status_state state = { 0 };
+		struct worktree *wt = worktrees[i++];
+		struct string_list update_refs = STRING_LIST_INIT_DUP;
+
+		if (wt->is_bare)
+			continue;
+
+		if (wt->head_ref) {
+			old = strmap_put(&current_checked_out_branches,
+					 wt->head_ref,
+					 xstrdup(wt->path));
+			free(old);
+		}
+
+		if (wt_status_check_rebase(wt, &state) &&
+		    (state.rebase_in_progress || state.rebase_interactive_in_progress) &&
+		    state.branch) {
+			struct strbuf ref = STRBUF_INIT;
+			strbuf_addf(&ref, "refs/heads/%s", state.branch);
+			old = strmap_put(&current_checked_out_branches,
+					 ref.buf,
+					 xstrdup(wt->path));
+			free(old);
+			strbuf_release(&ref);
+		}
+		wt_status_state_free_buffers(&state);
+
+		if (wt_status_check_bisect(wt, &state) &&
+		    state.branch) {
+			struct strbuf ref = STRBUF_INIT;
+			strbuf_addf(&ref, "refs/heads/%s", state.branch);
+			old = strmap_put(&current_checked_out_branches,
+					 ref.buf,
+					 xstrdup(wt->path));
+			free(old);
+			strbuf_release(&ref);
+		}
+		wt_status_state_free_buffers(&state);
+
+		if (!sequencer_get_update_refs_state(get_worktree_git_dir(wt),
+						     &update_refs)) {
+			struct string_list_item *item;
+			for_each_string_list_item(item, &update_refs) {
+				old = strmap_put(&current_checked_out_branches,
+						 item->string,
+						 xstrdup(wt->path));
+				free(old);
+			}
+			string_list_clear(&update_refs, 1);
+		}
+	}
+
+	free_worktrees(worktrees);
+}
+
+const char *branch_checked_out(const char *refname)
+{
+	prepare_checked_out_branches();
+	return strmap_get(&current_checked_out_branches, refname);
+}
+
 /*
  * Check if a branch 'name' can be created as a new branch; die otherwise.
  * 'force' can be used when it is OK for the named branch already exists.
@@ -377,9 +455,7 @@
  */
 int validate_new_branchname(const char *name, struct strbuf *ref, int force)
 {
-	struct worktree **worktrees;
-	const struct worktree *wt;
-
+	const char *path;
 	if (!validate_branchname(name, ref))
 		return 0;
 
@@ -387,13 +463,10 @@
 		die(_("a branch named '%s' already exists"),
 		    ref->buf + strlen("refs/heads/"));
 
-	worktrees = get_worktrees();
-	wt = find_shared_symref(worktrees, "HEAD", ref->buf);
-	if (wt && !wt->is_bare)
+	if ((path = branch_checked_out(ref->buf)))
 		die(_("cannot force update the branch '%s' "
 		      "checked out at '%s'"),
-		    ref->buf + strlen("refs/heads/"), wt->path);
-	free_worktrees(worktrees);
+		    ref->buf + strlen("refs/heads/"), path);
 
 	return 1;
 }
diff --git a/branch.h b/branch.h
index 560b6b9..ef56103 100644
--- a/branch.h
+++ b/branch.h
@@ -101,6 +101,13 @@
 				 const char *tracking_name, int force,
 				 int reflog, int quiet, enum branch_track track,
 				 int dry_run);
+
+/*
+ * If the branch at 'refname' is currently checked out in a worktree,
+ * then return the path to that worktree.
+ */
+const char *branch_checked_out(const char *refname);
+
 /*
  * Check if 'name' can be a valid name for a branch; die otherwise.
  * Return 1 if the named branch already exists; return 0 otherwise.
diff --git a/builtin.h b/builtin.h
index 40e9ecc..8901a34 100644
--- a/builtin.h
+++ b/builtin.h
@@ -144,6 +144,7 @@
 int cmd_credential_cache_daemon(int argc, const char **argv, const char *prefix);
 int cmd_credential_store(int argc, const char **argv, const char *prefix);
 int cmd_describe(int argc, const char **argv, const char *prefix);
+int cmd_diagnose(int argc, const char **argv, const char *prefix);
 int cmd_diff_files(int argc, const char **argv, const char *prefix);
 int cmd_diff_index(int argc, const char **argv, const char *prefix);
 int cmd_diff(int argc, const char **argv, const char *prefix);
diff --git a/builtin/am.c b/builtin/am.c
index 93bec62..39fea24 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -2301,7 +2301,7 @@
 	return 0;
 }
 
-static int git_am_config(const char *k, const char *v, void *cb)
+static int git_am_config(const char *k, const char *v, void *cb UNUSED)
 {
 	int status;
 
diff --git a/builtin/archive.c b/builtin/archive.c
index 7176b04..f094390 100644
--- a/builtin/archive.c
+++ b/builtin/archive.c
@@ -75,7 +75,7 @@
 
 #define PARSE_OPT_KEEP_ALL ( PARSE_OPT_KEEP_DASHDASH | 	\
 			     PARSE_OPT_KEEP_ARGV0 | 	\
-			     PARSE_OPT_KEEP_UNKNOWN |	\
+			     PARSE_OPT_KEEP_UNKNOWN_OPT |	\
 			     PARSE_OPT_NO_INTERNAL_HELP	)
 
 int cmd_archive(int argc, const char **argv, const char *prefix)
diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 8a052c7..501245f 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -329,8 +329,9 @@
 	return 0;
 }
 
-static int inc_nr(const char *refname, const struct object_id *oid,
-		  int flag, void *cb_data)
+static int inc_nr(const char *refname UNUSED,
+		  const struct object_id *oid UNUSED,
+		  int flag UNUSED, void *cb_data)
 {
 	unsigned int *nr = (unsigned int *)cb_data;
 	(*nr)++;
@@ -518,7 +519,7 @@
 }
 
 static int add_bisect_ref(const char *refname, const struct object_id *oid,
-			  int flags, void *cb)
+			  int flags UNUSED, void *cb)
 {
 	struct add_bisect_ref_data *data = cb;
 
@@ -1134,8 +1135,9 @@
 	return res;
 }
 
-static int get_first_good(const char *refname, const struct object_id *oid,
-			  int flag, void *cb_data)
+static int get_first_good(const char *refname UNUSED,
+			  const struct object_id *oid,
+			  int flag UNUSED, void *cb_data)
 {
 	oidcpy(cb_data, oid);
 	return 1;
@@ -1324,7 +1326,7 @@
 
 	argc = parse_options(argc, argv, prefix, options,
 			     git_bisect_helper_usage,
-			     PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_UNKNOWN);
+			     PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_UNKNOWN_OPT);
 
 	if (!cmdmode)
 		usage_with_options(git_bisect_helper_usage, options);
diff --git a/builtin/blame.c b/builtin/blame.c
index 02e3942..a9fe8cf 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -920,6 +920,7 @@
 			break;
 		case PARSE_OPT_HELP:
 		case PARSE_OPT_ERROR:
+		case PARSE_OPT_SUBCOMMAND:
 			exit(129);
 		case PARSE_OPT_COMPLETE:
 			exit(0);
diff --git a/builtin/branch.c b/builtin/branch.c
index 5d00d0b..55cd9a6 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -204,7 +204,6 @@
 static int delete_branches(int argc, const char **argv, int force, int kinds,
 			   int quiet)
 {
-	struct worktree **worktrees;
 	struct commit *head_rev = NULL;
 	struct object_id oid;
 	char *name = NULL;
@@ -242,8 +241,6 @@
 			die(_("Couldn't look up commit object for HEAD"));
 	}
 
-	worktrees = get_worktrees();
-
 	for (i = 0; i < argc; i++, strbuf_reset(&bname)) {
 		char *target = NULL;
 		int flags = 0;
@@ -253,12 +250,11 @@
 		name = mkpathdup(fmt, bname.buf);
 
 		if (kinds == FILTER_REFS_BRANCHES) {
-			const struct worktree *wt =
-				find_shared_symref(worktrees, "HEAD", name);
-			if (wt) {
+			const char *path;
+			if ((path = branch_checked_out(name))) {
 				error(_("Cannot delete branch '%s' "
 					"checked out at '%s'"),
-				      bname.buf, wt->path);
+				      bname.buf, path);
 				ret = 1;
 				continue;
 			}
@@ -315,7 +311,6 @@
 
 	free(name);
 	strbuf_release(&bname);
-	free_worktrees(worktrees);
 
 	return ret;
 }
diff --git a/builtin/bugreport.c b/builtin/bugreport.c
index 9de32bc..530895b 100644
--- a/builtin/bugreport.c
+++ b/builtin/bugreport.c
@@ -5,6 +5,7 @@
 #include "compat/compiler.h"
 #include "hook.h"
 #include "hook-list.h"
+#include "diagnose.h"
 
 
 static void get_system_info(struct strbuf *sys_info)
@@ -59,7 +60,7 @@
 }
 
 static const char * const bugreport_usage[] = {
-	N_("git bugreport [-o|--output-directory <file>] [-s|--suffix <format>]"),
+	N_("git bugreport [-o|--output-directory <file>] [-s|--suffix <format>] [--diagnose[=<mode>]"),
 	NULL
 };
 
@@ -98,16 +99,21 @@
 	int report = -1;
 	time_t now = time(NULL);
 	struct tm tm;
+	enum diagnose_mode diagnose = DIAGNOSE_NONE;
 	char *option_output = NULL;
 	char *option_suffix = "%Y-%m-%d-%H%M";
 	const char *user_relative_path = NULL;
 	char *prefixed_filename;
+	size_t output_path_len;
 
 	const struct option bugreport_options[] = {
+		OPT_CALLBACK_F(0, "diagnose", &diagnose, N_("mode"),
+			       N_("create an additional zip archive of detailed diagnostics (default 'stats')"),
+			       PARSE_OPT_OPTARG, option_parse_diagnose),
 		OPT_STRING('o', "output-directory", &option_output, N_("path"),
-			   N_("specify a destination for the bugreport file")),
+			   N_("specify a destination for the bugreport file(s)")),
 		OPT_STRING('s', "suffix", &option_suffix, N_("format"),
-			   N_("specify a strftime format suffix for the filename")),
+			   N_("specify a strftime format suffix for the filename(s)")),
 		OPT_END()
 	};
 
@@ -119,6 +125,7 @@
 					    option_output ? option_output : "");
 	strbuf_addstr(&report_path, prefixed_filename);
 	strbuf_complete(&report_path, '/');
+	output_path_len = report_path.len;
 
 	strbuf_addstr(&report_path, "git-bugreport-");
 	strbuf_addftime(&report_path, option_suffix, localtime_r(&now, &tm), 0, 0);
@@ -133,6 +140,20 @@
 		    report_path.buf);
 	}
 
+	/* Prepare diagnostics, if requested */
+	if (diagnose != DIAGNOSE_NONE) {
+		struct strbuf zip_path = STRBUF_INIT;
+		strbuf_add(&zip_path, report_path.buf, output_path_len);
+		strbuf_addstr(&zip_path, "git-diagnostics-");
+		strbuf_addftime(&zip_path, option_suffix, localtime_r(&now, &tm), 0, 0);
+		strbuf_addstr(&zip_path, ".zip");
+
+		if (create_diagnostics_archive(&zip_path, diagnose))
+			die_errno(_("unable to create diagnostics archive %s"), zip_path.buf);
+
+		strbuf_release(&zip_path);
+	}
+
 	/* Prepare the report contents */
 	get_bug_template(&buffer);
 
diff --git a/builtin/bundle.c b/builtin/bundle.c
index 2adad54..e80efce 100644
--- a/builtin/bundle.c
+++ b/builtin/bundle.c
@@ -195,30 +195,19 @@
 
 int cmd_bundle(int argc, const char **argv, const char *prefix)
 {
+	parse_opt_subcommand_fn *fn = NULL;
 	struct option options[] = {
+		OPT_SUBCOMMAND("create", &fn, cmd_bundle_create),
+		OPT_SUBCOMMAND("verify", &fn, cmd_bundle_verify),
+		OPT_SUBCOMMAND("list-heads", &fn, cmd_bundle_list_heads),
+		OPT_SUBCOMMAND("unbundle", &fn, cmd_bundle_unbundle),
 		OPT_END()
 	};
-	int result;
 
 	argc = parse_options(argc, argv, prefix, options, builtin_bundle_usage,
-		PARSE_OPT_STOP_AT_NON_OPTION);
+			     0);
 
 	packet_trace_identity("bundle");
 
-	if (argc < 2)
-		usage_with_options(builtin_bundle_usage, options);
-
-	else if (!strcmp(argv[0], "create"))
-		result = cmd_bundle_create(argc, argv, prefix);
-	else if (!strcmp(argv[0], "verify"))
-		result = cmd_bundle_verify(argc, argv, prefix);
-	else if (!strcmp(argv[0], "list-heads"))
-		result = cmd_bundle_list_heads(argc, argv, prefix);
-	else if (!strcmp(argv[0], "unbundle"))
-		result = cmd_bundle_unbundle(argc, argv, prefix);
-	else {
-		error(_("Unknown subcommand: %s"), argv[0]);
-		usage_with_options(builtin_bundle_usage, options);
-	}
-	return result ? 1 : 0;
+	return !!fn(argc, argv, prefix);
 }
diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 50cf389..989eee0 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -16,6 +16,7 @@
 #include "packfile.h"
 #include "object-store.h"
 #include "promisor-remote.h"
+#include "mailmap.h"
 
 enum batch_mode {
 	BATCH_MODE_CONTENTS,
@@ -31,11 +32,28 @@
 	int all_objects;
 	int unordered;
 	int transform_mode; /* may be 'w' or 'c' for --filters or --textconv */
+	int nul_terminated;
 	const char *format;
 };
 
 static const char *force_path;
 
+static struct string_list mailmap = STRING_LIST_INIT_NODUP;
+static int use_mailmap;
+
+static char *replace_idents_using_mailmap(char *, size_t *);
+
+static char *replace_idents_using_mailmap(char *object_buf, size_t *size)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char *headers[] = { "author ", "committer ", "tagger ", NULL };
+
+	strbuf_attach(&sb, object_buf, *size, *size + 1);
+	apply_mailmap_to_header(&sb, headers, &mailmap);
+	*size = sb.len;
+	return strbuf_detach(&sb, NULL);
+}
+
 static int filter_object(const char *path, unsigned mode,
 			 const struct object_id *oid,
 			 char **buf, unsigned long *size)
@@ -71,6 +89,7 @@
 static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 			int unknown_type)
 {
+	int ret;
 	struct object_id oid;
 	enum object_type type;
 	char *buf;
@@ -106,7 +125,8 @@
 		if (sb.len) {
 			printf("%s\n", sb.buf);
 			strbuf_release(&sb);
-			return 0;
+			ret = 0;
+			goto cleanup;
 		}
 		break;
 
@@ -115,7 +135,8 @@
 		if (oid_object_info_extended(the_repository, &oid, &oi, flags) < 0)
 			die("git cat-file: could not get object info");
 		printf("%"PRIuMAX"\n", (uintmax_t)size);
-		return 0;
+		ret = 0;
+		goto cleanup;
 
 	case 'e':
 		return !has_object_file(&oid);
@@ -123,8 +144,10 @@
 	case 'w':
 
 		if (filter_object(path, obj_context.mode,
-				  &oid, &buf, &size))
-			return -1;
+				  &oid, &buf, &size)) {
+			ret = -1;
+			goto cleanup;
+		}
 		break;
 
 	case 'c':
@@ -143,15 +166,24 @@
 			const char *ls_args[3] = { NULL };
 			ls_args[0] =  "ls-tree";
 			ls_args[1] =  obj_name;
-			return cmd_ls_tree(2, ls_args, NULL);
+			ret = cmd_ls_tree(2, ls_args, NULL);
+			goto cleanup;
 		}
 
-		if (type == OBJ_BLOB)
-			return stream_blob(&oid);
+		if (type == OBJ_BLOB) {
+			ret = stream_blob(&oid);
+			goto cleanup;
+		}
 		buf = read_object_file(&oid, &type, &size);
 		if (!buf)
 			die("Cannot read object %s", obj_name);
 
+		if (use_mailmap) {
+			size_t s = size;
+			buf = replace_idents_using_mailmap(buf, &s);
+			size = cast_size_t_to_ulong(s);
+		}
+
 		/* otherwise just spit out the data */
 		break;
 
@@ -172,8 +204,10 @@
 			} else
 				oidcpy(&blob_oid, &oid);
 
-			if (oid_object_info(the_repository, &blob_oid, NULL) == OBJ_BLOB)
-				return stream_blob(&blob_oid);
+			if (oid_object_info(the_repository, &blob_oid, NULL) == OBJ_BLOB) {
+				ret = stream_blob(&blob_oid);
+				goto cleanup;
+			}
 			/*
 			 * we attempted to dereference a tag to a blob
 			 * and failed; there may be new dereference
@@ -183,6 +217,12 @@
 		}
 		buf = read_object_with_reference(the_repository, &oid,
 						 exp_type_id, &size, NULL);
+
+		if (use_mailmap) {
+			size_t s = size;
+			buf = replace_idents_using_mailmap(buf, &s);
+			size = cast_size_t_to_ulong(s);
+		}
 		break;
 	}
 	default:
@@ -193,9 +233,11 @@
 		die("git cat-file %s: bad file", obj_name);
 
 	write_or_die(1, buf, size);
+	ret = 0;
+cleanup:
 	free(buf);
 	free(obj_context.path);
-	return 0;
+	return ret;
 }
 
 struct expand_data {
@@ -348,11 +390,18 @@
 		void *contents;
 
 		contents = read_object_file(oid, &type, &size);
+
+		if (use_mailmap) {
+			size_t s = size;
+			contents = replace_idents_using_mailmap(contents, &s);
+			size = cast_size_t_to_ulong(s);
+		}
+
 		if (!contents)
 			die("object %s disappeared", oid_to_hex(oid));
 		if (type != data->type)
 			die("object %s changed type!?", oid_to_hex(oid));
-		if (data->info.sizep && size != data->size)
+		if (data->info.sizep && size != data->size && !use_mailmap)
 			die("object %s changed size!?", oid_to_hex(oid));
 
 		batch_write(opt, contents, size);
@@ -602,12 +651,20 @@
 	struct queued_cmd *queued_cmd = NULL;
 	size_t alloc = 0, nr = 0;
 
-	while (!strbuf_getline(&input, stdin)) {
-		int i;
+	while (1) {
+		int i, ret;
 		const struct parse_cmd *cmd = NULL;
 		const char *p = NULL, *cmd_end;
 		struct queued_cmd call = {0};
 
+		if (opt->nul_terminated)
+			ret = strbuf_getline_nul(&input, stdin);
+		else
+			ret = strbuf_getline(&input, stdin);
+
+		if (ret)
+			break;
+
 		if (!input.len)
 			die(_("empty command in input"));
 		if (isspace(*input.buf))
@@ -655,6 +712,7 @@
 		free_cmds(queued_cmd, &nr);
 	}
 
+	free_cmds(queued_cmd, &nr);
 	free(queued_cmd);
 	strbuf_release(&input);
 }
@@ -750,7 +808,16 @@
 		goto cleanup;
 	}
 
-	while (strbuf_getline(&input, stdin) != EOF) {
+	while (1) {
+		int ret;
+		if (opt->nul_terminated)
+			ret = strbuf_getline_nul(&input, stdin);
+		else
+			ret = strbuf_getline(&input, stdin);
+
+		if (ret == EOF)
+			break;
+
 		if (data.split_on_whitespace) {
 			/*
 			 * Split at first whitespace, tying off the beginning
@@ -843,6 +910,8 @@
 		OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
 		OPT_BOOL(0, "allow-unknown-type", &unknown_type,
 			  N_("allow -s and -t to work with broken/corrupt objects")),
+		OPT_BOOL(0, "use-mailmap", &use_mailmap, N_("use mail map file")),
+		OPT_ALIAS(0, "mailmap", "use-mailmap"),
 		/* Batch mode */
 		OPT_GROUP(N_("Batch objects requested on stdin (or --batch-all-objects)")),
 		OPT_CALLBACK_F(0, "batch", &batch, N_("format"),
@@ -853,6 +922,7 @@
 			N_("like --batch, but don't emit <contents>"),
 			PARSE_OPT_OPTARG | PARSE_OPT_NONEG,
 			batch_option_callback),
+		OPT_BOOL('z', NULL, &batch.nul_terminated, N_("stdin is NUL-terminated")),
 		OPT_CALLBACK_F(0, "batch-command", &batch, N_("format"),
 			N_("read commands from stdin"),
 			PARSE_OPT_OPTARG | PARSE_OPT_NONEG,
@@ -885,6 +955,9 @@
 	opt_cw = (opt == 'c' || opt == 'w');
 	opt_epts = (opt == 'e' || opt == 'p' || opt == 't' || opt == 's');
 
+	if (use_mailmap)
+		read_mailmap(&mailmap);
+
 	/* --batch-all-objects? */
 	if (opt == 'b')
 		batch.all_objects = 1;
@@ -908,6 +981,9 @@
 	else if (batch.all_objects)
 		usage_msg_optf(_("'%s' requires a batch mode"), usage, options,
 			       "--batch-all-objects");
+	else if (batch.nul_terminated)
+		usage_msg_optf(_("'%s' requires a batch mode"), usage, options,
+			       "-z");
 
 	/* Batch defaults */
 	if (batch.buffer_output < 0)
diff --git a/builtin/check-ref-format.c b/builtin/check-ref-format.c
index bc67d3f..fd0e5f8 100644
--- a/builtin/check-ref-format.c
+++ b/builtin/check-ref-format.c
@@ -57,6 +57,8 @@
 	int normalize = 0;
 	int flags = 0;
 	const char *refname;
+	char *to_free = NULL;
+	int ret = 1;
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage(builtin_check_ref_format_usage);
@@ -81,11 +83,14 @@
 
 	refname = argv[i];
 	if (normalize)
-		refname = collapse_slashes(refname);
+		refname = to_free = collapse_slashes(refname);
 	if (check_refname_format(refname, flags))
-		return 1;
+		goto cleanup;
 	if (normalize)
 		printf("%s\n", refname);
 
-	return 0;
+	ret = 0;
+cleanup:
+	free(to_free);
+	return ret;
 }
diff --git a/builtin/checkout.c b/builtin/checkout.c
index cdd96cd..2a13239 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -125,7 +125,7 @@
 }
 
 static int update_some(const struct object_id *oid, struct strbuf *base,
-		const char *pathname, unsigned mode, void *context)
+		       const char *pathname, unsigned mode, void *context UNUSED)
 {
 	int len;
 	struct cache_entry *ce;
@@ -711,6 +711,26 @@
 	branch->path = strbuf_detach(&buf, NULL);
 }
 
+static void init_topts(struct unpack_trees_options *topts, int merge,
+		       int show_progress, int overwrite_ignore,
+		       struct commit *old_commit)
+{
+	memset(topts, 0, sizeof(*topts));
+	topts->head_idx = -1;
+	topts->src_index = &the_index;
+	topts->dst_index = &the_index;
+
+	setup_unpack_trees_porcelain(topts, "checkout");
+
+	topts->initial_checkout = is_cache_unborn();
+	topts->update = 1;
+	topts->merge = 1;
+	topts->quiet = merge && old_commit;
+	topts->verbose_update = show_progress;
+	topts->fn = twoway_merge;
+	topts->preserve_ignored = !overwrite_ignore;
+}
+
 static int merge_working_tree(const struct checkout_opts *opts,
 			      struct branch_info *old_branch_info,
 			      struct branch_info *new_branch_info,
@@ -741,13 +761,6 @@
 		struct unpack_trees_options topts;
 		const struct object_id *old_commit_oid;
 
-		memset(&topts, 0, sizeof(topts));
-		topts.head_idx = -1;
-		topts.src_index = &the_index;
-		topts.dst_index = &the_index;
-
-		setup_unpack_trees_porcelain(&topts, "checkout");
-
 		refresh_cache(REFRESH_QUIET);
 
 		if (unmerged_cache()) {
@@ -756,17 +769,12 @@
 		}
 
 		/* 2-way merge to the new branch */
-		topts.initial_checkout = is_cache_unborn();
-		topts.update = 1;
-		topts.merge = 1;
-		topts.quiet = opts->merge && old_branch_info->commit;
-		topts.verbose_update = opts->show_progress;
-		topts.fn = twoway_merge;
+		init_topts(&topts, opts->merge, opts->show_progress,
+			   opts->overwrite_ignore, old_branch_info->commit);
 		init_checkout_metadata(&topts.meta, new_branch_info->refname,
 				       new_branch_info->commit ?
 				       &new_branch_info->commit->object.oid :
 				       &new_branch_info->oid, NULL);
-		topts.preserve_ignored = !opts->overwrite_ignore;
 
 		old_commit_oid = old_branch_info->commit ?
 			&old_branch_info->commit->object.oid :
@@ -982,7 +990,7 @@
 
 static int add_pending_uninteresting_ref(const char *refname,
 					 const struct object_id *oid,
-					 int flags, void *cb_data)
+					 int flags UNUSED, void *cb_data)
 {
 	add_pending_oid(cb_data, refname, oid, UNINTERESTING);
 	return 0;
diff --git a/builtin/clone.c b/builtin/clone.c
index 9e0b2b4..e21d42d 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -34,6 +34,7 @@
 #include "list-objects-filter-options.h"
 #include "hook.h"
 #include "bundle.h"
+#include "bundle-uri.h"
 
 /*
  * Overall FIXMEs:
@@ -77,6 +78,7 @@
 static int config_filter_submodules = -1;    /* unspecified */
 static struct string_list server_options = STRING_LIST_INIT_NODUP;
 static int option_remote_submodules;
+static const char *bundle_uri;
 
 static int recurse_submodules_cb(const struct option *opt,
 				 const char *arg, int unset)
@@ -160,6 +162,8 @@
 		    N_("any cloned submodules will use their remote-tracking branch")),
 	OPT_BOOL(0, "sparse", &option_sparse_checkout,
 		    N_("initialize sparse-checkout file to include only files at root")),
+	OPT_STRING(0, "bundle-uri", &bundle_uri,
+		   N_("uri"), N_("a URI for downloading bundles before fetching from origin remote")),
 	OPT_END()
 };
 
@@ -494,6 +498,7 @@
 			/* if --branch=tag, pull the requested tag explicitly */
 			get_fetch_map(remote_head, tag_refspec, &tail, 0);
 		}
+		free_refs(remote_head);
 	} else {
 		int i;
 		for (i = 0; i < refspec->nr; i++)
@@ -932,6 +937,9 @@
 		option_no_checkout = 1;
 	}
 
+	if (bundle_uri && deepen)
+		die(_("--bundle-uri is incompatible with --depth, --shallow-since, and --shallow-exclude"));
+
 	repo_name = argv[0];
 
 	path = get_repo_path(repo_name, &is_bundle);
@@ -1231,6 +1239,18 @@
 	if (transport->smart_options && !deepen && !filter_options.choice)
 		transport->smart_options->check_self_contained_and_connected = 1;
 
+	/*
+	 * Before fetching from the remote, download and install bundle
+	 * data from the --bundle-uri option.
+	 */
+	if (bundle_uri) {
+		/* At this point, we need the_repository to match the cloned repo. */
+		if (repo_init(the_repository, git_dir, work_tree))
+			warning(_("failed to initialize the repo, skipping bundle URI"));
+		else if (fetch_bundle_uri(the_repository, bundle_uri))
+			warning(_("failed to fetch objects from bundle URI '%s'"),
+				bundle_uri);
+	}
 
 	strvec_push(&transport_ls_refs_options.ref_prefixes, "HEAD");
 	refspec_ref_prefixes(&remote->fetch,
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index 51c4040..51557fe 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -58,7 +58,7 @@
 	return parse_options_concat(common_opts, to);
 }
 
-static int graph_verify(int argc, const char **argv)
+static int graph_verify(int argc, const char **argv, const char *prefix)
 {
 	struct commit_graph *graph = NULL;
 	struct object_directory *odb = NULL;
@@ -80,7 +80,7 @@
 	trace2_cmd_mode("verify");
 
 	opts.progress = isatty(2);
-	argc = parse_options(argc, argv, NULL,
+	argc = parse_options(argc, argv, prefix,
 			     options,
 			     builtin_commit_graph_verify_usage, 0);
 	if (argc)
@@ -179,7 +179,7 @@
 }
 
 static int git_commit_graph_write_config(const char *var, const char *value,
-					 void *cb)
+					 void *cb UNUSED)
 {
 	if (!strcmp(var, "commitgraph.maxnewfilters"))
 		write_opts.max_new_filters = git_config_int(var, value);
@@ -190,7 +190,7 @@
 	return 0;
 }
 
-static int graph_write(int argc, const char **argv)
+static int graph_write(int argc, const char **argv, const char *prefix)
 {
 	struct string_list pack_indexes = STRING_LIST_INIT_DUP;
 	struct strbuf buf = STRBUF_INIT;
@@ -241,7 +241,7 @@
 
 	git_config(git_commit_graph_write_config, &opts);
 
-	argc = parse_options(argc, argv, NULL,
+	argc = parse_options(argc, argv, prefix,
 			     options,
 			     builtin_commit_graph_write_usage, 0);
 	if (argc)
@@ -307,26 +307,22 @@
 
 int cmd_commit_graph(int argc, const char **argv, const char *prefix)
 {
-	struct option *builtin_commit_graph_options = common_opts;
+	parse_opt_subcommand_fn *fn = NULL;
+	struct option builtin_commit_graph_options[] = {
+		OPT_SUBCOMMAND("verify", &fn, graph_verify),
+		OPT_SUBCOMMAND("write", &fn, graph_write),
+		OPT_END(),
+	};
+	struct option *options = parse_options_concat(builtin_commit_graph_options, common_opts);
 
 	git_config(git_default_config, NULL);
-	argc = parse_options(argc, argv, prefix,
-			     builtin_commit_graph_options,
-			     builtin_commit_graph_usage,
-			     PARSE_OPT_STOP_AT_NON_OPTION);
-	if (!argc)
-		goto usage;
 
 	read_replace_refs = 0;
 	save_commit_buffer = 0;
 
-	if (!strcmp(argv[0], "verify"))
-		return graph_verify(argc, argv);
-	else if (argc && !strcmp(argv[0], "write"))
-		return graph_write(argc, argv);
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_commit_graph_usage, 0);
+	FREE_AND_NULL(options);
 
-	error(_("unrecognized subcommand: %s"), argv[0]);
-usage:
-	usage_with_options(builtin_commit_graph_usage,
-			   builtin_commit_graph_options);
+	return fn(argc, argv, prefix);
 }
diff --git a/builtin/config.c b/builtin/config.c
index e7b88a9..753e5fa 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -207,7 +207,8 @@
 	strbuf_addch(buf, term);
 }
 
-static int show_all_config(const char *key_, const char *value_, void *cb)
+static int show_all_config(const char *key_, const char *value_,
+			   void *cb UNUSED)
 {
 	if (show_origin || show_scope) {
 		struct strbuf buf = STRBUF_INIT;
@@ -458,7 +459,8 @@
 static const char *get_colorbool_slot;
 static char parsed_color[COLOR_MAXLEN];
 
-static int git_get_color_config(const char *var, const char *value, void *cb)
+static int git_get_color_config(const char *var, const char *value,
+				void *cb UNUSED)
 {
 	if (!strcmp(var, get_color_slot)) {
 		if (!value)
@@ -490,7 +492,7 @@
 static int get_diff_color_found;
 static int get_color_ui_found;
 static int git_get_colorbool_config(const char *var, const char *value,
-		void *cb)
+				    void *data UNUSED)
 {
 	if (!strcmp(var, get_colorbool_slot))
 		get_colorbool_found = git_config_colorbool(var, value);
diff --git a/builtin/describe.c b/builtin/describe.c
index a76f1a1..e17c4b4 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -63,7 +63,7 @@
 	N_("head"), N_("lightweight"), N_("annotated"),
 };
 
-static int commit_name_neq(const void *unused_cmp_data,
+static int commit_name_neq(const void *cmp_data UNUSED,
 			   const struct hashmap_entry *eptr,
 			   const struct hashmap_entry *entry_or_key,
 			   const void *peeled)
@@ -140,7 +140,8 @@
 	}
 }
 
-static int get_name(const char *path, const struct object_id *oid, int flag, void *cb_data)
+static int get_name(const char *path, const struct object_id *oid,
+		    int flag UNUSED, void *cb_data UNUSED)
 {
 	int is_tag = 0;
 	struct object_id peeled;
diff --git a/builtin/diagnose.c b/builtin/diagnose.c
new file mode 100644
index 0000000..cd260c2
--- /dev/null
+++ b/builtin/diagnose.c
@@ -0,0 +1,61 @@
+#include "builtin.h"
+#include "parse-options.h"
+#include "diagnose.h"
+
+static const char * const diagnose_usage[] = {
+	N_("git diagnose [-o|--output-directory <path>] [-s|--suffix <format>] [--mode=<mode>]"),
+	NULL
+};
+
+int cmd_diagnose(int argc, const char **argv, const char *prefix)
+{
+	struct strbuf zip_path = STRBUF_INIT;
+	time_t now = time(NULL);
+	struct tm tm;
+	enum diagnose_mode mode = DIAGNOSE_STATS;
+	char *option_output = NULL;
+	char *option_suffix = "%Y-%m-%d-%H%M";
+	char *prefixed_filename;
+
+	const struct option diagnose_options[] = {
+		OPT_STRING('o', "output-directory", &option_output, N_("path"),
+			   N_("specify a destination for the diagnostics archive")),
+		OPT_STRING('s', "suffix", &option_suffix, N_("format"),
+			   N_("specify a strftime format suffix for the filename")),
+		OPT_CALLBACK_F(0, "mode", &mode, N_("(stats|all)"),
+			       N_("specify the content of the diagnostic archive"),
+			       PARSE_OPT_NONEG, option_parse_diagnose),
+		OPT_END()
+	};
+
+	argc = parse_options(argc, argv, prefix, diagnose_options,
+			     diagnose_usage, 0);
+
+	/* Prepare the path to put the result */
+	prefixed_filename = prefix_filename(prefix,
+					    option_output ? option_output : "");
+	strbuf_addstr(&zip_path, prefixed_filename);
+	strbuf_complete(&zip_path, '/');
+
+	strbuf_addstr(&zip_path, "git-diagnostics-");
+	strbuf_addftime(&zip_path, option_suffix, localtime_r(&now, &tm), 0, 0);
+	strbuf_addstr(&zip_path, ".zip");
+
+	switch (safe_create_leading_directories(zip_path.buf)) {
+	case SCLD_OK:
+	case SCLD_EXISTS:
+		break;
+	default:
+		die_errno(_("could not create leading directories for '%s'"),
+			  zip_path.buf);
+	}
+
+	/* Prepare diagnostics */
+	if (create_diagnostics_archive(&zip_path, mode))
+		die_errno(_("unable to create diagnostics archive %s"),
+			  zip_path.buf);
+
+	free(prefixed_filename);
+	strbuf_release(&zip_path);
+	return 0;
+}
diff --git a/builtin/difftool.c b/builtin/difftool.c
index b3c509b..4b10ad1 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -125,10 +125,10 @@
 	char path[FLEX_ARRAY];
 };
 
-static int working_tree_entry_cmp(const void *unused_cmp_data,
+static int working_tree_entry_cmp(const void *cmp_data UNUSED,
 				  const struct hashmap_entry *eptr,
 				  const struct hashmap_entry *entry_or_key,
-				  const void *unused_keydata)
+				  const void *keydata UNUSED)
 {
 	const struct working_tree_entry *a, *b;
 
@@ -148,10 +148,10 @@
 	const char path[FLEX_ARRAY];
 };
 
-static int pair_cmp(const void *unused_cmp_data,
+static int pair_cmp(const void *cmp_data UNUSED,
 		    const struct hashmap_entry *eptr,
 		    const struct hashmap_entry *entry_or_key,
-		    const void *unused_keydata)
+		    const void *keydata UNUSED)
 {
 	const struct pair_entry *a, *b;
 
@@ -184,7 +184,7 @@
 	char path[FLEX_ARRAY];
 };
 
-static int path_entry_cmp(const void *unused_cmp_data,
+static int path_entry_cmp(const void *cmp_data UNUSED,
 			  const struct hashmap_entry *eptr,
 			  const struct hashmap_entry *entry_or_key,
 			  const void *key)
@@ -716,7 +716,7 @@
 	symlinks = has_symlinks;
 
 	argc = parse_options(argc, argv, prefix, builtin_difftool_options,
-			     builtin_difftool_usage, PARSE_OPT_KEEP_UNKNOWN |
+			     builtin_difftool_usage, PARSE_OPT_KEEP_UNKNOWN_OPT |
 			     PARSE_OPT_KEEP_DASHDASH);
 
 	if (tool_help)
diff --git a/builtin/env--helper.c b/builtin/env--helper.c
index 2734909..ea04c16 100644
--- a/builtin/env--helper.c
+++ b/builtin/env--helper.c
@@ -50,7 +50,7 @@
 	};
 
 	argc = parse_options(argc, argv, prefix, opts, env__helper_usage,
-			     PARSE_OPT_KEEP_UNKNOWN);
+			     PARSE_OPT_KEEP_UNKNOWN_OPT);
 	if (env_default && !*env_default)
 		usage_with_options(env__helper_usage, opts);
 	if (!cmdmode)
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index e1748fb..3b3314e 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -119,7 +119,7 @@
 	size_t orig_len;
 };
 
-static int anonymized_entry_cmp(const void *unused_cmp_data,
+static int anonymized_entry_cmp(const void *cmp_data UNUSED,
 				const struct hashmap_entry *eptr,
 				const struct hashmap_entry *entry_or_key,
 				const void *keydata)
@@ -1221,7 +1221,7 @@
 	revs.sources = &revision_sources;
 	revs.rewrite_parents = 1;
 	argc = parse_options(argc, argv, prefix, options, fast_export_usage,
-			PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN);
+			PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN_OPT);
 	argc = setup_revisions(argc, argv, &revs, NULL);
 	if (argc > 1)
 		usage_with_options (fast_export_usage, options);
diff --git a/builtin/fast-import.c b/builtin/fast-import.c
index 14113cf..7134683 100644
--- a/builtin/fast-import.c
+++ b/builtin/fast-import.c
@@ -46,7 +46,7 @@
 		depth : DEPTH_BITS;
 };
 
-static int object_entry_hashcmp(const void *map_data,
+static int object_entry_hashcmp(const void *map_data UNUSED,
 				const struct hashmap_entry *eptr,
 				const struct hashmap_entry *entry_or_key,
 				const void *keydata)
diff --git a/builtin/fetch.c b/builtin/fetch.c
index acc4e89..3aecbe4 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -301,7 +301,7 @@
 	char refname[FLEX_ARRAY];
 };
 
-static int refname_hash_entry_cmp(const void *hashmap_cmp_fn_data,
+static int refname_hash_entry_cmp(const void *hashmap_cmp_fn_data UNUSED,
 				  const struct hashmap_entry *eptr,
 				  const struct hashmap_entry *entry_or_key,
 				  const void *keydata)
@@ -329,7 +329,7 @@
 
 static int add_one_refname(const char *refname,
 			   const struct object_id *oid,
-			   int flag, void *cbdata)
+			   int flag UNUSED, void *cbdata)
 {
 	struct hashmap *refname_map = cbdata;
 
@@ -490,7 +490,9 @@
 			continue;
 		if (!rs->items[i].dst ||
 		    (rs->items[i].src &&
-		     !strncmp(rs->items[i].src, "refs/tags/", 10))) {
+		     !strncmp(rs->items[i].src,
+			      ref_namespace[NAMESPACE_TAGS].ref,
+			      strlen(ref_namespace[NAMESPACE_TAGS].ref)))) {
 			int j;
 
 			free(rs->items[i].src);
@@ -506,7 +508,7 @@
 		}
 
 		old_dst = rs->items[i].dst;
-		strbuf_addstr(&new_dst, "refs/prefetch/");
+		strbuf_addstr(&new_dst, ref_namespace[NAMESPACE_PREFETCH].ref);
 
 		/*
 		 * If old_dst starts with "refs/", then place
@@ -881,11 +883,9 @@
 static int update_local_ref(struct ref *ref,
 			    struct ref_transaction *transaction,
 			    const char *remote, const struct ref *remote_ref,
-			    struct strbuf *display, int summary_width,
-			    struct worktree **worktrees)
+			    struct strbuf *display, int summary_width)
 {
 	struct commit *current = NULL, *updated;
-	const struct worktree *wt;
 	const char *pretty_ref = prettify_refname(ref->name);
 	int fast_forward = 0;
 
@@ -900,16 +900,14 @@
 	}
 
 	if (!update_head_ok &&
-	    (wt = find_shared_symref(worktrees, "HEAD", ref->name)) &&
-	    !wt->is_bare && !is_null_oid(&ref->old_oid)) {
+	    !is_null_oid(&ref->old_oid) &&
+	    branch_checked_out(ref->name)) {
 		/*
 		 * If this is the head, and it's not okay to update
 		 * the head, and the old value of the head isn't empty...
 		 */
 		format_display(display, '!', _("[rejected]"),
-			       wt->is_current ?
-				       _("can't fetch in current branch") :
-				       _("checked out in another worktree"),
+			       _("can't fetch into checked-out branch"),
 			       remote, pretty_ref, summary_width);
 		return 1;
 	}
@@ -1110,10 +1108,10 @@
 static int store_updated_refs(const char *raw_url, const char *remote_name,
 			      int connectivity_checked,
 			      struct ref_transaction *transaction, struct ref *ref_map,
-			      struct fetch_head *fetch_head, struct worktree **worktrees)
+			      struct fetch_head *fetch_head)
 {
 	int url_len, i, rc = 0;
-	struct strbuf note = STRBUF_INIT, err = STRBUF_INIT;
+	struct strbuf note = STRBUF_INIT;
 	const char *what, *kind;
 	struct ref *rm;
 	char *url;
@@ -1240,8 +1238,7 @@
 			strbuf_reset(&note);
 			if (ref) {
 				rc |= update_local_ref(ref, transaction, what,
-						       rm, &note, summary_width,
-						       worktrees);
+						       rm, &note, summary_width);
 				free(ref);
 			} else if (write_fetch_head || dry_run) {
 				/*
@@ -1281,7 +1278,6 @@
 
  abort:
 	strbuf_release(&note);
-	strbuf_release(&err);
 	free(url);
 	return rc;
 }
@@ -1332,8 +1328,7 @@
 static int fetch_and_consume_refs(struct transport *transport,
 				  struct ref_transaction *transaction,
 				  struct ref *ref_map,
-				  struct fetch_head *fetch_head,
-				  struct worktree **worktrees)
+				  struct fetch_head *fetch_head)
 {
 	int connectivity_checked = 1;
 	int ret;
@@ -1356,7 +1351,7 @@
 	trace2_region_enter("fetch", "consume_refs", the_repository);
 	ret = store_updated_refs(transport->url, transport->remote->name,
 				 connectivity_checked, transaction, ref_map,
-				 fetch_head, worktrees);
+				 fetch_head);
 	trace2_region_leave("fetch", "consume_refs", the_repository);
 
 out:
@@ -1434,19 +1429,16 @@
 	return result;
 }
 
-static void check_not_current_branch(struct ref *ref_map,
-				     struct worktree **worktrees)
+static void check_not_current_branch(struct ref *ref_map)
 {
-	const struct worktree *wt;
+	const char *path;
 	for (; ref_map; ref_map = ref_map->next)
 		if (ref_map->peer_ref &&
 		    starts_with(ref_map->peer_ref->name, "refs/heads/") &&
-		    (wt = find_shared_symref(worktrees, "HEAD",
-					     ref_map->peer_ref->name)) &&
-		    !wt->is_bare)
+		    (path = branch_checked_out(ref_map->peer_ref->name)))
 			die(_("refusing to fetch into branch '%s' "
 			      "checked out at '%s'"),
-			    ref_map->peer_ref->name, wt->path);
+			    ref_map->peer_ref->name, path);
 }
 
 static int truncate_fetch_head(void)
@@ -1472,8 +1464,9 @@
 }
 
 
-static int add_oid(const char *refname, const struct object_id *oid, int flags,
-		   void *cb_data)
+static int add_oid(const char *refname UNUSED,
+		   const struct object_id *oid,
+		   int flags UNUSED, void *cb_data)
 {
 	struct oid_array *oids = cb_data;
 
@@ -1549,8 +1542,7 @@
 static int backfill_tags(struct transport *transport,
 			 struct ref_transaction *transaction,
 			 struct ref *ref_map,
-			 struct fetch_head *fetch_head,
-			 struct worktree **worktrees)
+			 struct fetch_head *fetch_head)
 {
 	int retcode, cannot_reuse;
 
@@ -1571,7 +1563,7 @@
 	transport_set_option(transport, TRANS_OPT_FOLLOWTAGS, NULL);
 	transport_set_option(transport, TRANS_OPT_DEPTH, "0");
 	transport_set_option(transport, TRANS_OPT_DEEPEN_RELATIVE, NULL);
-	retcode = fetch_and_consume_refs(transport, transaction, ref_map, fetch_head, worktrees);
+	retcode = fetch_and_consume_refs(transport, transaction, ref_map, fetch_head);
 
 	if (gsecondary) {
 		transport_disconnect(gsecondary);
@@ -1592,7 +1584,6 @@
 	struct transport_ls_refs_options transport_ls_refs_options =
 		TRANSPORT_LS_REFS_OPTIONS_INIT;
 	int must_list_refs = 1;
-	struct worktree **worktrees = get_worktrees();
 	struct fetch_head fetch_head = { 0 };
 	struct strbuf err = STRBUF_INIT;
 
@@ -1662,7 +1653,7 @@
 	ref_map = get_ref_map(transport->remote, remote_refs, rs,
 			      tags, &autotags);
 	if (!update_head_ok)
-		check_not_current_branch(ref_map, worktrees);
+		check_not_current_branch(ref_map);
 
 	retcode = open_fetch_head(&fetch_head);
 	if (retcode)
@@ -1695,7 +1686,7 @@
 			retcode = 1;
 	}
 
-	if (fetch_and_consume_refs(transport, transaction, ref_map, &fetch_head, worktrees)) {
+	if (fetch_and_consume_refs(transport, transaction, ref_map, &fetch_head)) {
 		retcode = 1;
 		goto cleanup;
 	}
@@ -1718,7 +1709,7 @@
 			 * the transaction and don't commit anything.
 			 */
 			if (backfill_tags(transport, transaction, tags_ref_map,
-					  &fetch_head, worktrees))
+					  &fetch_head))
 				retcode = 1;
 		}
 
@@ -1803,7 +1794,6 @@
 	close_fetch_head(&fetch_head);
 	strbuf_release(&err);
 	free_refs(ref_map);
-	free_worktrees(worktrees);
 	return retcode;
 }
 
diff --git a/builtin/fsck.c b/builtin/fsck.c
index 6c73092..f7916f0 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -488,8 +488,9 @@
 }
 
 static int fsck_handle_reflog_ent(struct object_id *ooid, struct object_id *noid,
-		const char *email, timestamp_t timestamp, int tz,
-		const char *message, void *cb_data)
+				  const char *email UNUSED,
+				  timestamp_t timestamp, int tz UNUSED,
+				  const char *message UNUSED, void *cb_data)
 {
 	const char *refname = cb_data;
 
@@ -502,8 +503,9 @@
 	return 0;
 }
 
-static int fsck_handle_reflog(const char *logname, const struct object_id *oid,
-			      int flag, void *cb_data)
+static int fsck_handle_reflog(const char *logname,
+			      const struct object_id *oid UNUSED,
+			      int flag UNUSED, void *cb_data)
 {
 	struct strbuf refname = STRBUF_INIT;
 
@@ -514,7 +516,7 @@
 }
 
 static int fsck_handle_ref(const char *refname, const struct object_id *oid,
-			   int flag, void *cb_data)
+			   int flag UNUSED, void *cb_data UNUSED)
 {
 	struct object *obj;
 
diff --git a/builtin/gc.c b/builtin/gc.c
index 021e925..0accc02 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -168,9 +168,15 @@
 static int maintenance_task_pack_refs(MAYBE_UNUSED struct maintenance_run_opts *opts)
 {
 	struct strvec pack_refs_cmd = STRVEC_INIT;
+	int ret;
+
 	strvec_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 
-	return run_command_v_opt(pack_refs_cmd.v, RUN_GIT_CMD);
+	ret = run_command_v_opt(pack_refs_cmd.v, RUN_GIT_CMD);
+
+	strvec_clear(&pack_refs_cmd);
+
+	return ret;
 }
 
 static int too_many_loose_objects(void)
@@ -776,8 +782,9 @@
 	int limit;
 };
 
-static int dfs_on_ref(const char *refname,
-		      const struct object_id *oid, int flags,
+static int dfs_on_ref(const char *refname UNUSED,
+		      const struct object_id *oid,
+		      int flags UNUSED,
 		      void *cb_data)
 {
 	struct cg_auto_data *data = (struct cg_auto_data *)cb_data;
@@ -904,12 +911,6 @@
 
 static int maintenance_task_prefetch(struct maintenance_run_opts *opts)
 {
-	git_config_set_multivar_gently("log.excludedecoration",
-					"refs/prefetch/",
-					"refs/prefetch/",
-					CONFIG_FLAGS_FIXED_VALUE |
-					CONFIG_FLAGS_MULTI_REPLACE);
-
 	if (for_each_remote(fetch_remote, opts)) {
 		error(_("failed to prefetch remotes"));
 		return 1;
@@ -1459,14 +1460,28 @@
 	return strbuf_detach(&sb, NULL);
 }
 
-static int maintenance_register(void)
+static char const * const builtin_maintenance_register_usage[] = {
+	N_("git maintenance register"),
+	NULL
+};
+
+static int maintenance_register(int argc, const char **argv, const char *prefix)
 {
+	struct option options[] = {
+		OPT_END(),
+	};
 	int rc;
 	char *config_value;
 	struct child_process config_set = CHILD_PROCESS_INIT;
 	struct child_process config_get = CHILD_PROCESS_INIT;
 	char *maintpath = get_maintpath();
 
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_maintenance_register_usage, 0);
+	if (argc)
+		usage_with_options(builtin_maintenance_register_usage,
+				   options);
+
 	/* Disable foreground maintenance */
 	git_config_set("maintenance.auto", "false");
 
@@ -1503,12 +1518,26 @@
 	return rc;
 }
 
-static int maintenance_unregister(void)
+static char const * const builtin_maintenance_unregister_usage[] = {
+	N_("git maintenance unregister"),
+	NULL
+};
+
+static int maintenance_unregister(int argc, const char **argv, const char *prefix)
 {
+	struct option options[] = {
+		OPT_END(),
+	};
 	int rc;
 	struct child_process config_unset = CHILD_PROCESS_INIT;
 	char *maintpath = get_maintpath();
 
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_maintenance_unregister_usage, 0);
+	if (argc)
+		usage_with_options(builtin_maintenance_unregister_usage,
+				   options);
+
 	config_unset.git_cmd = 1;
 	strvec_pushl(&config_unset.args, "config", "--global", "--unset",
 		     "--fixed-value", "maintenance.repo", maintpath, NULL);
@@ -2059,6 +2088,7 @@
 	struct child_process crontab_edit = CHILD_PROCESS_INIT;
 	FILE *cron_list, *cron_in;
 	struct strbuf line = STRBUF_INIT;
+	struct tempfile *tmpedit = NULL;
 
 	get_schedule_cmd(&cmd, NULL);
 	strvec_split(&crontab_list.args, cmd);
@@ -2073,6 +2103,17 @@
 	/* Ignore exit code, as an empty crontab will return error. */
 	finish_command(&crontab_list);
 
+	tmpedit = mks_tempfile_t(".git_cron_edit_tmpXXXXXX");
+	if (!tmpedit) {
+		result = error(_("failed to create crontab temporary file"));
+		goto out;
+	}
+	cron_in = fdopen_tempfile(tmpedit, "w");
+	if (!cron_in) {
+		result = error(_("failed to open temporary file"));
+		goto out;
+	}
+
 	/*
 	 * Read from the .lock file, filtering out the old
 	 * schedule while appending the new schedule.
@@ -2080,19 +2121,6 @@
 	cron_list = fdopen(fd, "r");
 	rewind(cron_list);
 
-	strvec_split(&crontab_edit.args, cmd);
-	crontab_edit.in = -1;
-	crontab_edit.git_cmd = 0;
-
-	if (start_command(&crontab_edit))
-		return error(_("failed to run 'crontab'; your system might not support 'cron'"));
-
-	cron_in = fdopen(crontab_edit.in, "w");
-	if (!cron_in) {
-		result = error(_("failed to open stdin of 'crontab'"));
-		goto done_editing;
-	}
-
 	while (!strbuf_getline_lf(&line, cron_list)) {
 		if (!in_old_region && !strcmp(line.buf, BEGIN_LINE))
 			in_old_region = 1;
@@ -2126,14 +2154,22 @@
 	}
 
 	fflush(cron_in);
-	fclose(cron_in);
-	close(crontab_edit.in);
 
-done_editing:
+	strvec_split(&crontab_edit.args, cmd);
+	strvec_push(&crontab_edit.args, get_tempfile_path(tmpedit));
+	crontab_edit.git_cmd = 0;
+
+	if (start_command(&crontab_edit)) {
+		result = error(_("failed to run 'crontab'; your system might not support 'cron'"));
+		goto out;
+	}
+
 	if (finish_command(&crontab_edit))
 		result = error(_("'crontab' died"));
 	else
 		fclose(cron_list);
+out:
+	delete_tempfile(&tmpedit);
 	return result;
 }
 
@@ -2490,6 +2526,7 @@
 			PARSE_OPT_NONEG, maintenance_opt_scheduler),
 		OPT_END()
 	};
+	const char *register_args[] = { "register", NULL };
 
 	argc = parse_options(argc, argv, prefix, options,
 			     builtin_maintenance_start_usage, 0);
@@ -2499,34 +2536,46 @@
 	opts.scheduler = resolve_scheduler(opts.scheduler);
 	validate_scheduler(opts.scheduler);
 
-	if (maintenance_register())
+	if (maintenance_register(ARRAY_SIZE(register_args)-1, register_args, NULL))
 		warning(_("failed to add repo to global config"));
 	return update_background_schedule(&opts, 1);
 }
 
-static int maintenance_stop(void)
+static const char *const builtin_maintenance_stop_usage[] = {
+	N_("git maintenance stop"),
+	NULL
+};
+
+static int maintenance_stop(int argc, const char **argv, const char *prefix)
 {
+	struct option options[] = {
+		OPT_END()
+	};
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_maintenance_stop_usage, 0);
+	if (argc)
+		usage_with_options(builtin_maintenance_stop_usage, options);
 	return update_background_schedule(NULL, 0);
 }
 
-static const char builtin_maintenance_usage[] =	N_("git maintenance <subcommand> [<options>]");
+static const char * const builtin_maintenance_usage[] = {
+	N_("git maintenance <subcommand> [<options>]"),
+	NULL,
+};
 
 int cmd_maintenance(int argc, const char **argv, const char *prefix)
 {
-	if (argc < 2 ||
-	    (argc == 2 && !strcmp(argv[1], "-h")))
-		usage(builtin_maintenance_usage);
+	parse_opt_subcommand_fn *fn = NULL;
+	struct option builtin_maintenance_options[] = {
+		OPT_SUBCOMMAND("run", &fn, maintenance_run),
+		OPT_SUBCOMMAND("start", &fn, maintenance_start),
+		OPT_SUBCOMMAND("stop", &fn, maintenance_stop),
+		OPT_SUBCOMMAND("register", &fn, maintenance_register),
+		OPT_SUBCOMMAND("unregister", &fn, maintenance_unregister),
+		OPT_END(),
+	};
 
-	if (!strcmp(argv[1], "run"))
-		return maintenance_run(argc - 1, argv + 1, prefix);
-	if (!strcmp(argv[1], "start"))
-		return maintenance_start(argc - 1, argv + 1, prefix);
-	if (!strcmp(argv[1], "stop"))
-		return maintenance_stop();
-	if (!strcmp(argv[1], "register"))
-		return maintenance_register();
-	if (!strcmp(argv[1], "unregister"))
-		return maintenance_unregister();
-
-	die(_("invalid subcommand: %s"), argv[1]);
+	argc = parse_options(argc, argv, prefix, builtin_maintenance_options,
+			     builtin_maintenance_usage, 0);
+	return fn(argc, argv, prefix);
 }
diff --git a/builtin/grep.c b/builtin/grep.c
index bcb07ea..e6bcdf8 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -961,6 +961,8 @@
 		OPT_BOOL_F(0, "ext-grep", &external_grep_allowed__ignored,
 			   N_("allow calling of grep(1) (ignored by this build)"),
 			   PARSE_OPT_NOCOMPLETE),
+		OPT_INTEGER('m', "max-count", &opt.max_count,
+			N_("maximum number of results per file")),
 		OPT_END()
 	};
 	grep_prefix = prefix;
@@ -1101,6 +1103,13 @@
 	if (recurse_submodules && untracked)
 		die(_("--untracked not supported with --recurse-submodules"));
 
+	/*
+	 * Optimize out the case where the amount of matches is limited to zero.
+	 * We do this to keep results consistent with GNU grep(1).
+	 */
+	if (opt.max_count == 0)
+		return 1;
+
 	if (show_in_pager) {
 		if (num_threads > 1)
 			warning(_("invalid option combination, ignoring --threads"));
diff --git a/builtin/help.c b/builtin/help.c
index 222f994..09ac428 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -43,6 +43,8 @@
 	HELP_ACTION_ALL = 1,
 	HELP_ACTION_GUIDES,
 	HELP_ACTION_CONFIG,
+	HELP_ACTION_USER_INTERFACES,
+	HELP_ACTION_DEVELOPER_INTERFACES,
 	HELP_ACTION_CONFIG_FOR_COMPLETION,
 	HELP_ACTION_CONFIG_SECTIONS_FOR_COMPLETION,
 } cmd_mode;
@@ -69,6 +71,12 @@
 
 	OPT_CMDMODE('g', "guides", &cmd_mode, N_("print list of useful guides"),
 		    HELP_ACTION_GUIDES),
+	OPT_CMDMODE(0, "user-interfaces", &cmd_mode,
+		    N_("print list of user-facing repository, command and file interfaces"),
+		    HELP_ACTION_USER_INTERFACES),
+	OPT_CMDMODE(0, "developer-interfaces", &cmd_mode,
+		    N_("print list of file formats, protocols and other developer interfaces"),
+		    HELP_ACTION_DEVELOPER_INTERFACES),
 	OPT_CMDMODE('c', "config", &cmd_mode, N_("print all configuration variable names"),
 		    HELP_ACTION_CONFIG),
 	OPT_CMDMODE_F(0, "config-for-completion", &cmd_mode, "",
@@ -81,9 +89,11 @@
 
 static const char * const builtin_help_usage[] = {
 	"git help [-a|--all] [--[no-]verbose]] [--[no-]external-commands] [--[no-]aliases]",
-	N_("git help [[-i|--info] [-m|--man] [-w|--web]] [<command>]"),
+	N_("git help [[-i|--info] [-m|--man] [-w|--web]] [<command>|<doc>]"),
 	"git help [-g|--guides]",
 	"git help [-c|--config]",
+	"git help [--user-interfaces]",
+	"git help [--developer-interfaces]",
 	NULL
 };
 
@@ -654,6 +664,14 @@
 		opt_mode_usage(argc, "--config-for-completion", help_format);
 		list_config_help(SHOW_CONFIG_VARS);
 		return 0;
+	case HELP_ACTION_USER_INTERFACES:
+		opt_mode_usage(argc, "--user-interfaces", help_format);
+		list_user_interfaces_help();
+		return 0;
+	case HELP_ACTION_DEVELOPER_INTERFACES:
+		opt_mode_usage(argc, "--developer-interfaces", help_format);
+		list_developer_interfaces_help();
+		return 0;
 	case HELP_ACTION_CONFIG_SECTIONS_FOR_COMPLETION:
 		opt_mode_usage(argc, "--config-sections-for-completion",
 			       help_format);
diff --git a/builtin/hook.c b/builtin/hook.c
index 54e5c6e..b6530d1 100644
--- a/builtin/hook.c
+++ b/builtin/hook.c
@@ -67,18 +67,14 @@
 
 int cmd_hook(int argc, const char **argv, const char *prefix)
 {
+	parse_opt_subcommand_fn *fn = NULL;
 	struct option builtin_hook_options[] = {
+		OPT_SUBCOMMAND("run", &fn, run),
 		OPT_END(),
 	};
 
 	argc = parse_options(argc, argv, NULL, builtin_hook_options,
-			     builtin_hook_usage, PARSE_OPT_STOP_AT_NON_OPTION);
-	if (!argc)
-		goto usage;
+			     builtin_hook_usage, 0);
 
-	if (!strcmp(argv[0], "run"))
-		return run(argc, argv, prefix);
-
-usage:
-	usage_with_options(builtin_hook_usage, builtin_hook_options);
+	return fn(argc, argv, prefix);
 }
diff --git a/builtin/log.c b/builtin/log.c
index 88a5e98..ee19dc5 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -52,6 +52,7 @@
 static int decoration_style;
 static int decoration_given;
 static int use_mailmap_config = 1;
+static unsigned int force_in_body_from;
 static const char *fmt_patch_subject_prefix = "PATCH";
 static int fmt_patch_name_max = FORMAT_PATCH_NAME_MAX_DEFAULT;
 static const char *fmt_pretty;
@@ -101,6 +102,20 @@
 	return -1;
 }
 
+static int use_default_decoration_filter = 1;
+static struct string_list decorate_refs_exclude = STRING_LIST_INIT_NODUP;
+static struct string_list decorate_refs_exclude_config = STRING_LIST_INIT_NODUP;
+static struct string_list decorate_refs_include = STRING_LIST_INIT_NODUP;
+
+static int clear_decorations_callback(const struct option *opt,
+					    const char *arg, int unset)
+{
+	string_list_clear(&decorate_refs_include, 0);
+	string_list_clear(&decorate_refs_exclude, 0);
+	use_default_decoration_filter = 0;
+	return 0;
+}
+
 static int decorate_callback(const struct option *opt, const char *arg, int unset)
 {
 	if (unset)
@@ -162,18 +177,61 @@
 		parse_date_format(default_date_mode, &rev->date_mode);
 }
 
+static void set_default_decoration_filter(struct decoration_filter *decoration_filter)
+{
+	int i;
+	char *value = NULL;
+	struct string_list *include = decoration_filter->include_ref_pattern;
+	const struct string_list *config_exclude =
+			git_config_get_value_multi("log.excludeDecoration");
+
+	if (config_exclude) {
+		struct string_list_item *item;
+		for_each_string_list_item(item, config_exclude)
+			string_list_append(decoration_filter->exclude_ref_config_pattern,
+					   item->string);
+	}
+
+	/*
+	 * By default, decorate_all is disabled. Enable it if
+	 * log.initialDecorationSet=all. Don't ever disable it by config,
+	 * since the command-line takes precedent.
+	 */
+	if (use_default_decoration_filter &&
+	    !git_config_get_string("log.initialdecorationset", &value) &&
+	    !strcmp("all", value))
+		use_default_decoration_filter = 0;
+	free(value);
+
+	if (!use_default_decoration_filter ||
+	    decoration_filter->exclude_ref_pattern->nr ||
+	    decoration_filter->include_ref_pattern->nr ||
+	    decoration_filter->exclude_ref_config_pattern->nr)
+		return;
+
+	/*
+	 * No command-line or config options were given, so
+	 * populate with sensible defaults.
+	 */
+	for (i = 0; i < ARRAY_SIZE(ref_namespace); i++) {
+		if (!ref_namespace[i].decoration)
+			continue;
+
+		string_list_append(include, ref_namespace[i].ref);
+	}
+}
+
 static void cmd_log_init_finish(int argc, const char **argv, const char *prefix,
 			 struct rev_info *rev, struct setup_revision_opt *opt)
 {
 	struct userformat_want w;
 	int quiet = 0, source = 0, mailmap;
 	static struct line_opt_callback_data line_cb = {NULL, NULL, STRING_LIST_INIT_DUP};
-	static struct string_list decorate_refs_exclude = STRING_LIST_INIT_NODUP;
-	static struct string_list decorate_refs_exclude_config = STRING_LIST_INIT_NODUP;
-	static struct string_list decorate_refs_include = STRING_LIST_INIT_NODUP;
-	struct decoration_filter decoration_filter = {&decorate_refs_include,
-						      &decorate_refs_exclude,
-						      &decorate_refs_exclude_config};
+	struct decoration_filter decoration_filter = {
+		.exclude_ref_pattern = &decorate_refs_exclude,
+		.include_ref_pattern = &decorate_refs_include,
+		.exclude_ref_config_pattern = &decorate_refs_exclude_config,
+	};
 	static struct revision_sources revision_sources;
 
 	const struct option builtin_log_options[] = {
@@ -181,6 +239,10 @@
 		OPT_BOOL(0, "source", &source, N_("show source")),
 		OPT_BOOL(0, "use-mailmap", &mailmap, N_("use mail map file")),
 		OPT_ALIAS(0, "mailmap", "use-mailmap"),
+		OPT_CALLBACK_F(0, "clear-decorations", NULL, NULL,
+			       N_("clear all previously-defined decoration filters"),
+			       PARSE_OPT_NOARG | PARSE_OPT_NONEG,
+			       clear_decorations_callback),
 		OPT_STRING_LIST(0, "decorate-refs", &decorate_refs_include,
 				N_("pattern"), N_("only decorate refs that match <pattern>")),
 		OPT_STRING_LIST(0, "decorate-refs-exclude", &decorate_refs_exclude,
@@ -199,7 +261,7 @@
 	mailmap = use_mailmap_config;
 	argc = parse_options(argc, argv, prefix,
 			     builtin_log_options, builtin_log_usage,
-			     PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN |
+			     PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN_OPT |
 			     PARSE_OPT_KEEP_DASHDASH);
 
 	if (quiet)
@@ -265,16 +327,7 @@
 	}
 
 	if (decoration_style || rev->simplify_by_decoration) {
-		const struct string_list *config_exclude =
-			repo_config_get_value_multi(the_repository,
-						    "log.excludeDecoration");
-
-		if (config_exclude) {
-			struct string_list_item *item;
-			for_each_string_list_item(item, config_exclude)
-				string_list_append(&decorate_refs_exclude_config,
-						   item->string);
-		}
+		set_default_decoration_filter(&decoration_filter);
 
 		if (decoration_style)
 			rev->show_decorations = 1;
@@ -645,9 +698,10 @@
 	return 0;
 }
 
-static int show_tree_object(const struct object_id *oid,
-		struct strbuf *base,
-		const char *pathname, unsigned mode, void *context)
+static int show_tree_object(const struct object_id *oid UNUSED,
+			    struct strbuf *base UNUSED,
+			    const char *pathname, unsigned mode,
+			    void *context)
 {
 	FILE *file = context;
 	fprintf(file, "%s%s\n", pathname, S_ISDIR(mode) ? "/" : "");
@@ -668,10 +722,10 @@
 int cmd_show(int argc, const char **argv, const char *prefix)
 {
 	struct rev_info rev;
-	struct object_array_entry *objects;
+	unsigned int i;
 	struct setup_revision_opt opt;
 	struct pathspec match_all;
-	int i, count, ret = 0;
+	int ret = 0;
 
 	init_log_defaults();
 	git_config(git_log_config, NULL);
@@ -698,12 +752,10 @@
 	if (!rev.no_walk)
 		return cmd_log_deinit(cmd_log_walk(&rev), &rev);
 
-	count = rev.pending.nr;
-	objects = rev.pending.objects;
 	rev.diffopt.no_free = 1;
-	for (i = 0; i < count && !ret; i++) {
-		struct object *o = objects[i].item;
-		const char *name = objects[i].name;
+	for (i = 0; i < rev.pending.nr && !ret; i++) {
+		struct object *o = rev.pending.objects[i].item;
+		const char *name = rev.pending.objects[i].name;
 		switch (o->type) {
 		case OBJ_BLOB:
 			ret = show_blob_object(&o->oid, &rev, name);
@@ -726,7 +778,7 @@
 			if (!o)
 				ret = error(_("could not read object %s"),
 					    oid_to_hex(oid));
-			objects[i].item = o;
+			rev.pending.objects[i].item = o;
 			i--;
 			break;
 		}
@@ -743,11 +795,24 @@
 			rev.shown_one = 1;
 			break;
 		case OBJ_COMMIT:
-			rev.pending.nr = rev.pending.alloc = 0;
-			rev.pending.objects = NULL;
+		{
+			struct object_array old;
+			struct object_array blank = OBJECT_ARRAY_INIT;
+
+			memcpy(&old, &rev.pending, sizeof(old));
+			memcpy(&rev.pending, &blank, sizeof(rev.pending));
+
 			add_object_array(o, name, &rev.pending);
 			ret = cmd_log_walk_no_free(&rev);
+
+			/*
+			 * No need for
+			 * object_array_clear(&pending). It was
+			 * cleared already in prepare_revision_walk()
+			 */
+			memcpy(&rev.pending, &old, sizeof(rev.pending));
 			break;
+		}
 		default:
 			ret = error(_("unknown type: %d"), o->type);
 		}
@@ -995,6 +1060,10 @@
 			from = NULL;
 		return 0;
 	}
+	if (!strcmp(var, "format.forceinbodyfrom")) {
+		force_in_body_from = git_config_bool(var, value);
+		return 0;
+	}
 	if (!strcmp(var, "format.notes")) {
 		int b = git_parse_maybe_bool(value);
 		if (b < 0)
@@ -1886,6 +1955,8 @@
 			   N_("show changes against <refspec> in cover letter or single patch")),
 		OPT_INTEGER(0, "creation-factor", &creation_factor,
 			    N_("percentage by which creation is weighted")),
+		OPT_BOOL(0, "force-in-body-from", &force_in_body_from,
+			 N_("show in-body From: even if identical to the e-mail header")),
 		OPT_END()
 	};
 
@@ -1926,9 +1997,11 @@
 	 */
 	argc = parse_options(argc, argv, prefix, builtin_format_patch_options,
 			     builtin_format_patch_usage,
-			     PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN |
+			     PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN_OPT |
 			     PARSE_OPT_KEEP_DASHDASH);
 
+	rev.force_in_body_from = force_in_body_from;
+
 	/* Make sure "0000-$sub.patch" gives non-negative length for $sub */
 	if (fmt_patch_name_max <= strlen("0000-") + strlen(fmt_patch_suffix))
 		fmt_patch_name_max = strlen("0000-") + strlen(fmt_patch_suffix);
diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index e791b65..779dc18 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -11,6 +11,7 @@
 #include "quote.h"
 #include "dir.h"
 #include "builtin.h"
+#include "strbuf.h"
 #include "tree.h"
 #include "cache-tree.h"
 #include "parse-options.h"
@@ -48,6 +49,7 @@
 static const char *with_tree;
 static int exc_given;
 static int exclude_args;
+static const char *format;
 
 static const char *tag_cached = "";
 static const char *tag_unmerged = "";
@@ -85,6 +87,16 @@
 				   stdout, line_terminator);
 }
 
+static void write_name_to_buf(struct strbuf *sb, const char *name)
+{
+	const char *rel = relative_path(name, prefix_len ? prefix : NULL, sb);
+
+	if (line_terminator)
+		quote_c_style(rel, sb, NULL, 0);
+	else
+		strbuf_addstr(sb, rel);
+}
+
 static const char *get_tag(const struct cache_entry *ce, const char *tag)
 {
 	static char alttag[4];
@@ -222,6 +234,73 @@
 	repo_clear(&subrepo);
 }
 
+struct show_index_data {
+	const char *pathname;
+	struct index_state *istate;
+	const struct cache_entry *ce;
+};
+
+static size_t expand_show_index(struct strbuf *sb, const char *start,
+				void *context)
+{
+	struct show_index_data *data = context;
+	const char *end;
+	const char *p;
+	size_t len = strbuf_expand_literal_cb(sb, start, NULL);
+	struct stat st;
+
+	if (len)
+		return len;
+	if (*start != '(')
+		die(_("bad ls-files format: element '%s' "
+		      "does not start with '('"), start);
+
+	end = strchr(start + 1, ')');
+	if (!end)
+		die(_("bad ls-files format: element '%s'"
+		      "does not end in ')'"), start);
+
+	len = end - start + 1;
+	if (skip_prefix(start, "(objectmode)", &p))
+		strbuf_addf(sb, "%06o", data->ce->ce_mode);
+	else if (skip_prefix(start, "(objectname)", &p))
+		strbuf_add_unique_abbrev(sb, &data->ce->oid, abbrev);
+	else if (skip_prefix(start, "(stage)", &p))
+		strbuf_addf(sb, "%d", ce_stage(data->ce));
+	else if (skip_prefix(start, "(eolinfo:index)", &p))
+		strbuf_addstr(sb, S_ISREG(data->ce->ce_mode) ?
+			      get_cached_convert_stats_ascii(data->istate,
+			      data->ce->name) : "");
+	else if (skip_prefix(start, "(eolinfo:worktree)", &p))
+		strbuf_addstr(sb, !lstat(data->pathname, &st) &&
+			      S_ISREG(st.st_mode) ?
+			      get_wt_convert_stats_ascii(data->pathname) : "");
+	else if (skip_prefix(start, "(eolattr)", &p))
+		strbuf_addstr(sb, get_convert_attr_ascii(data->istate,
+			      data->pathname));
+	else if (skip_prefix(start, "(path)", &p))
+		write_name_to_buf(sb, data->pathname);
+	else
+		die(_("bad ls-files format: %%%.*s"), (int)len, start);
+
+	return len;
+}
+
+static void show_ce_fmt(struct repository *repo, const struct cache_entry *ce,
+			const char *format, const char *fullname) {
+	struct show_index_data data = {
+		.pathname = fullname,
+		.istate = repo->index,
+		.ce = ce,
+	};
+	struct strbuf sb = STRBUF_INIT;
+
+	strbuf_expand(&sb, format, expand_show_index, &data);
+	strbuf_addch(&sb, line_terminator);
+	fwrite(sb.buf, sb.len, 1, stdout);
+	strbuf_release(&sb);
+}
+
 static void show_ce(struct repository *repo, struct dir_struct *dir,
 		    const struct cache_entry *ce, const char *fullname,
 		    const char *tag)
@@ -236,6 +315,12 @@
 				  max_prefix_len, ps_matched,
 				  S_ISDIR(ce->ce_mode) ||
 				  S_ISGITLINK(ce->ce_mode))) {
+		if (format) {
+			show_ce_fmt(repo, ce, format, fullname);
+			print_debug(ce);
+			return;
+		}
+
 		tag = get_tag(ce, tag);
 
 		if (!show_stage) {
@@ -675,6 +760,9 @@
 			 N_("suppress duplicate entries")),
 		OPT_BOOL(0, "sparse", &show_sparse_dirs,
 			 N_("show sparse directories in the presence of a sparse index")),
+		OPT_STRING_F(0, "format", &format, N_("format"),
+			     N_("format to use for the output"),
+			     PARSE_OPT_NONEG),
 		OPT_END()
 	};
 	int ret = 0;
@@ -699,6 +787,13 @@
 	for (i = 0; i < exclude_list.nr; i++) {
 		add_pattern(exclude_list.items[i].string, "", 0, pl, --exclude_args);
 	}
+
+	if (format && (show_stage || show_others || show_killed ||
+		show_resolve_undo || skipping_duplicates || show_eol || show_tag))
+			usage_msg_opt(_("--format cannot be used with -s, -o, -k, -t, "
+				      "--resolve-undo, --deduplicate, --eol"),
+				      ls_files_usage, builtin_ls_files_options);
+
 	if (show_tag || show_valid_bit || show_fsmonitor_bit) {
 		tag_cached = "H ";
 		tag_unmerged = "M ";
diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
index e279be8..c3ea092 100644
--- a/builtin/ls-tree.c
+++ b/builtin/ls-tree.c
@@ -142,7 +142,7 @@
 }
 
 static int show_tree_fmt(const struct object_id *oid, struct strbuf *base,
-			 const char *pathname, unsigned mode, void *context)
+			 const char *pathname, unsigned mode, void *context UNUSED)
 {
 	size_t baselen;
 	int recurse = 0;
@@ -213,7 +213,7 @@
 
 static int show_tree_default(const struct object_id *oid, struct strbuf *base,
 			     const char *pathname, unsigned mode,
-			     void *context)
+			     void *context UNUSED)
 {
 	int early;
 	int recurse;
@@ -230,7 +230,8 @@
 }
 
 static int show_tree_long(const struct object_id *oid, struct strbuf *base,
-			  const char *pathname, unsigned mode, void *context)
+			  const char *pathname, unsigned mode,
+			  void *context UNUSED)
 {
 	int early;
 	int recurse;
@@ -259,7 +260,8 @@
 }
 
 static int show_tree_name_only(const struct object_id *oid, struct strbuf *base,
-			       const char *pathname, unsigned mode, void *context)
+			       const char *pathname, unsigned mode,
+			       void *context UNUSED)
 {
 	int early;
 	int recurse;
@@ -279,7 +281,8 @@
 }
 
 static int show_tree_object(const struct object_id *oid, struct strbuf *base,
-			    const char *pathname, unsigned mode, void *context)
+			    const char *pathname, unsigned mode,
+			    void *context UNUSED)
 {
 	int early;
 	int recurse;
diff --git a/builtin/merge-file.c b/builtin/merge-file.c
index e695867..c923bbf 100644
--- a/builtin/merge-file.c
+++ b/builtin/merge-file.c
@@ -25,10 +25,10 @@
 
 int cmd_merge_file(int argc, const char **argv, const char *prefix)
 {
-	const char *names[3] = { NULL, NULL, NULL };
-	mmfile_t mmfs[3];
-	mmbuffer_t result = {NULL, 0};
-	xmparam_t xmp = {{0}};
+	const char *names[3] = { 0 };
+	mmfile_t mmfs[3] = { 0 };
+	mmbuffer_t result = { 0 };
+	xmparam_t xmp = { 0 };
 	int ret = 0, i = 0, to_stdout = 0;
 	int quiet = 0;
 	struct option options[] = {
@@ -71,21 +71,24 @@
 
 	for (i = 0; i < 3; i++) {
 		char *fname;
-		int ret;
+		mmfile_t *mmf = mmfs + i;
 
 		if (!names[i])
 			names[i] = argv[i];
 
 		fname = prefix_filename(prefix, argv[i]);
-		ret = read_mmfile(mmfs + i, fname);
+
+		if (read_mmfile(mmf, fname))
+			ret = -1;
+		else if (mmf->size > MAX_XDIFF_SIZE ||
+			 buffer_is_binary(mmf->ptr, mmf->size))
+			ret = error("Cannot merge binary files: %s",
+				    argv[i]);
+
 		free(fname);
 		if (ret)
-			return -1;
+			goto cleanup;
 
-		if (mmfs[i].size > MAX_XDIFF_SIZE ||
-		    buffer_is_binary(mmfs[i].ptr, mmfs[i].size))
-			return error("Cannot merge binary files: %s",
-					argv[i]);
 	}
 
 	xmp.ancestor = names[1];
@@ -93,9 +96,6 @@
 	xmp.file2 = names[2];
 	ret = xdl_merge(mmfs + 1, mmfs + 0, mmfs + 2, &xmp, &result);
 
-	for (i = 0; i < 3; i++)
-		free(mmfs[i].ptr);
-
 	if (ret >= 0) {
 		const char *filename = argv[0];
 		char *fpath = prefix_filename(prefix, argv[0]);
@@ -116,5 +116,9 @@
 	if (ret > 127)
 		ret = 127;
 
+cleanup:
+	for (i = 0; i < 3; i++)
+		free(mmfs[i].ptr);
+
 	return ret;
 }
diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c
index 5dc94d6..ae57829 100644
--- a/builtin/merge-tree.c
+++ b/builtin/merge-tree.c
@@ -2,13 +2,18 @@
 #include "builtin.h"
 #include "tree-walk.h"
 #include "xdiff-interface.h"
+#include "help.h"
+#include "commit-reach.h"
+#include "merge-ort.h"
 #include "object-store.h"
+#include "parse-options.h"
 #include "repository.h"
 #include "blob.h"
 #include "exec-cmd.h"
 #include "merge-blobs.h"
+#include "quote.h"
 
-static const char merge_tree_usage[] = "git merge-tree <base-tree> <branch1> <branch2>";
+static int line_termination = '\n';
 
 struct merge_list {
 	struct merge_list *next;
@@ -28,7 +33,7 @@
 	merge_result_end = &entry->next;
 }
 
-static void merge_trees(struct tree_desc t[3], const char *base);
+static void trivial_merge_trees(struct tree_desc t[3], const char *base);
 
 static const char *explanation(struct merge_list *entry)
 {
@@ -225,7 +230,7 @@
 	buf2 = fill_tree_descriptor(r, t + 2, ENTRY_OID(n + 2));
 #undef ENTRY_OID
 
-	merge_trees(t, newbase);
+	trivial_merge_trees(t, newbase);
 
 	free(buf0);
 	free(buf1);
@@ -342,7 +347,7 @@
 	return mask;
 }
 
-static void merge_trees(struct tree_desc t[3], const char *base)
+static void trivial_merge_trees(struct tree_desc t[3], const char *base)
 {
 	struct traverse_info info;
 
@@ -366,19 +371,18 @@
 	return buf;
 }
 
-int cmd_merge_tree(int argc, const char **argv, const char *prefix)
+static int trivial_merge(const char *base,
+			 const char *branch1,
+			 const char *branch2)
 {
 	struct repository *r = the_repository;
 	struct tree_desc t[3];
 	void *buf1, *buf2, *buf3;
 
-	if (argc != 4)
-		usage(merge_tree_usage);
-
-	buf1 = get_tree_descriptor(r, t+0, argv[1]);
-	buf2 = get_tree_descriptor(r, t+1, argv[2]);
-	buf3 = get_tree_descriptor(r, t+2, argv[3]);
-	merge_trees(t, "");
+	buf1 = get_tree_descriptor(r, t+0, base);
+	buf2 = get_tree_descriptor(r, t+1, branch1);
+	buf3 = get_tree_descriptor(r, t+2, branch2);
+	trivial_merge_trees(t, "");
 	free(buf1);
 	free(buf2);
 	free(buf3);
@@ -386,3 +390,162 @@
 	show_result();
 	return 0;
 }
+
+enum mode {
+	MODE_UNKNOWN,
+	MODE_TRIVIAL,
+	MODE_REAL,
+};
+
+struct merge_tree_options {
+	int mode;
+	int allow_unrelated_histories;
+	int show_messages;
+	int name_only;
+};
+
+static int real_merge(struct merge_tree_options *o,
+		      const char *branch1, const char *branch2,
+		      const char *prefix)
+{
+	struct commit *parent1, *parent2;
+	struct commit_list *merge_bases = NULL;
+	struct merge_options opt;
+	struct merge_result result = { 0 };
+
+	parent1 = get_merge_parent(branch1);
+	if (!parent1)
+		help_unknown_ref(branch1, "merge-tree",
+				 _("not something we can merge"));
+
+	parent2 = get_merge_parent(branch2);
+	if (!parent2)
+		help_unknown_ref(branch2, "merge-tree",
+				 _("not something we can merge"));
+
+	init_merge_options(&opt, the_repository);
+
+	opt.show_rename_progress = 0;
+
+	opt.branch1 = branch1;
+	opt.branch2 = branch2;
+
+	/*
+	 * Get the merge bases, in reverse order; see comment above
+	 * merge_incore_recursive in merge-ort.h
+	 */
+	merge_bases = get_merge_bases(parent1, parent2);
+	if (!merge_bases && !o->allow_unrelated_histories)
+		die(_("refusing to merge unrelated histories"));
+	merge_bases = reverse_commit_list(merge_bases);
+
+	merge_incore_recursive(&opt, merge_bases, parent1, parent2, &result);
+	if (result.clean < 0)
+		die(_("failure to merge"));
+
+	if (o->show_messages == -1)
+		o->show_messages = !result.clean;
+
+	printf("%s%c", oid_to_hex(&result.tree->object.oid), line_termination);
+	if (!result.clean) {
+		struct string_list conflicted_files = STRING_LIST_INIT_NODUP;
+		const char *last = NULL;
+		int i;
+
+		merge_get_conflicted_files(&result, &conflicted_files);
+		for (i = 0; i < conflicted_files.nr; i++) {
+			const char *name = conflicted_files.items[i].string;
+			struct stage_info *c = conflicted_files.items[i].util;
+			if (!o->name_only)
+				printf("%06o %s %d\t",
+				       c->mode, oid_to_hex(&c->oid), c->stage);
+			else if (last && !strcmp(last, name))
+				continue;
+			write_name_quoted_relative(
+				name, prefix, stdout, line_termination);
+			last = name;
+		}
+		string_list_clear(&conflicted_files, 1);
+	}
+	if (o->show_messages) {
+		putchar(line_termination);
+		merge_display_update_messages(&opt, line_termination == '\0',
+					      &result);
+	}
+	merge_finalize(&opt, &result);
+	return !result.clean; /* result.clean < 0 handled above */
+}
+
+int cmd_merge_tree(int argc, const char **argv, const char *prefix)
+{
+	struct merge_tree_options o = { .show_messages = -1 };
+	int expected_remaining_argc;
+	int original_argc;
+
+	const char * const merge_tree_usage[] = {
+		N_("git merge-tree [--write-tree] [<options>] <branch1> <branch2>"),
+		N_("git merge-tree [--trivial-merge] <base-tree> <branch1> <branch2>"),
+		NULL
+	};
+	struct option mt_options[] = {
+		OPT_CMDMODE(0, "write-tree", &o.mode,
+			    N_("do a real merge instead of a trivial merge"),
+			    MODE_REAL),
+		OPT_CMDMODE(0, "trivial-merge", &o.mode,
+			    N_("do a trivial merge only"), MODE_TRIVIAL),
+		OPT_BOOL(0, "messages", &o.show_messages,
+			 N_("also show informational/conflict messages")),
+		OPT_SET_INT('z', NULL, &line_termination,
+			    N_("separate paths with the NUL character"), '\0'),
+		OPT_BOOL_F(0, "name-only",
+			   &o.name_only,
+			   N_("list filenames without modes/oids/stages"),
+			   PARSE_OPT_NONEG),
+		OPT_BOOL_F(0, "allow-unrelated-histories",
+			   &o.allow_unrelated_histories,
+			   N_("allow merging unrelated histories"),
+			   PARSE_OPT_NONEG),
+		OPT_END()
+	};
+
+	/* Parse arguments */
+	original_argc = argc - 1; /* ignoring argv[0] */
+	argc = parse_options(argc, argv, prefix, mt_options,
+			     merge_tree_usage, PARSE_OPT_STOP_AT_NON_OPTION);
+	switch (o.mode) {
+	default:
+		BUG("unexpected command mode %d", o.mode);
+	case MODE_UNKNOWN:
+		switch (argc) {
+		default:
+			usage_with_options(merge_tree_usage, mt_options);
+		case 2:
+			o.mode = MODE_REAL;
+			break;
+		case 3:
+			o.mode = MODE_TRIVIAL;
+			break;
+		}
+		expected_remaining_argc = argc;
+		break;
+	case MODE_REAL:
+		expected_remaining_argc = 2;
+		break;
+	case MODE_TRIVIAL:
+		expected_remaining_argc = 3;
+		/* Removal of `--trivial-merge` is expected */
+		original_argc--;
+		break;
+	}
+	if (o.mode == MODE_TRIVIAL && argc < original_argc)
+		die(_("--trivial-merge is incompatible with all other options"));
+
+	if (argc != expected_remaining_argc)
+		usage_with_options(merge_tree_usage, mt_options);
+
+	/* Do the relevant type of merge */
+	if (o.mode == MODE_REAL)
+		return real_merge(&o, argv[0], argv[1], prefix);
+	else
+		return trivial_merge(argv[0], argv[1], argv[2]);
+}
diff --git a/builtin/merge.c b/builtin/merge.c
index d9784d4..5900b81 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -313,8 +313,16 @@
 	int len;
 	struct child_process cp = CHILD_PROCESS_INIT;
 	struct strbuf buffer = STRBUF_INIT;
+	struct lock_file lock_file = LOCK_INIT;
+	int fd;
 	int rc = -1;
 
+	fd = repo_hold_locked_index(the_repository, &lock_file, 0);
+	refresh_cache(REFRESH_QUIET);
+	if (0 <= fd)
+		repo_update_index_if_able(the_repository, &lock_file);
+	rollback_lock_file(&lock_file);
+
 	strvec_pushl(&cp.args, "stash", "create", NULL);
 	cp.out = -1;
 	cp.git_cmd = 1;
@@ -375,24 +383,26 @@
 static void restore_state(const struct object_id *head,
 			  const struct object_id *stash)
 {
-	struct strbuf sb = STRBUF_INIT;
-	const char *args[] = { "stash", "apply", NULL, NULL };
-
-	if (is_null_oid(stash))
-		return;
+	struct strvec args = STRVEC_INIT;
 
 	reset_hard(head, 1);
 
-	args[2] = oid_to_hex(stash);
+	if (is_null_oid(stash))
+		goto refresh_cache;
+
+	strvec_pushl(&args, "stash", "apply", "--index", "--quiet", NULL);
+	strvec_push(&args, oid_to_hex(stash));
 
 	/*
 	 * It is OK to ignore error here, for example when there was
 	 * nothing to restore.
 	 */
-	run_command_v_opt(args, RUN_GIT_CMD);
+	run_command_v_opt(args.v, RUN_GIT_CMD);
+	strvec_clear(&args);
 
-	strbuf_release(&sb);
-	refresh_cache(REFRESH_QUIET);
+refresh_cache:
+	if (discard_cache() < 0 || read_cache() < 0)
+		die(_("could not read index"));
 }
 
 /* This is called when no merge was necessary. */
@@ -493,7 +503,8 @@
 	/* Run a post-merge hook */
 	run_hooks_l("post-merge", squash ? "1" : "0", NULL);
 
-	apply_autostash(git_path_merge_autostash(the_repository));
+	if (new_head)
+		apply_autostash(git_path_merge_autostash(the_repository));
 	strbuf_release(&reflog_message);
 }
 
@@ -502,7 +513,6 @@
 {
 	struct commit *remote_head;
 	struct object_id branch_head;
-	struct strbuf buf = STRBUF_INIT;
 	struct strbuf bname = STRBUF_INIT;
 	struct merge_remote_desc *desc;
 	const char *ptr;
@@ -590,7 +600,6 @@
 		oid_to_hex(&remote_head->object.oid), remote);
 cleanup:
 	free(found_ref);
-	strbuf_release(&buf);
 	strbuf_release(&bname);
 }
 
@@ -758,8 +767,10 @@
 		else
 			clean = merge_recursive(&o, head, remoteheads->item,
 						reversed, &result);
-		if (clean < 0)
-			exit(128);
+		if (clean < 0) {
+			rollback_lock_file(&lock);
+			return 2;
+		}
 		if (write_locked_index(&the_index, &lock,
 				       COMMIT_LOCK | SKIP_IF_UNCHANGED))
 			die(_("unable to write %s"), get_index_file());
@@ -1603,6 +1614,21 @@
 		 */
 		refresh_cache(REFRESH_QUIET);
 		if (allow_trivial && fast_forward != FF_ONLY) {
+			/*
+			 * Must first ensure that index matches HEAD before
+			 * attempting a trivial merge.
+			 */
+			struct tree *head_tree = get_commit_tree(head_commit);
+			struct strbuf sb = STRBUF_INIT;
+
+			if (repo_index_has_changes(the_repository, head_tree,
+						   &sb)) {
+				error(_("Your local changes to the following files would be overwritten by merge:\n  %s"),
+				      sb.buf);
+				strbuf_release(&sb);
+				return 2;
+			}
+
 			/* See if it is really trivial. */
 			git_committer_info(IDENT_STRICT);
 			printf(_("Trying really trivial in-index merge...\n"));
@@ -1659,15 +1685,15 @@
 	 * tree in the index -- this means that the index must be in
 	 * sync with the head commit.  The strategies are responsible
 	 * to ensure this.
+	 *
+	 * Stash away the local changes so that we can try more than one
+	 * and/or recover from merge strategies bailing while leaving the
+	 * index and working tree polluted.
 	 */
-	if (use_strategies_nr == 1 ||
-	    /*
-	     * Stash away the local changes so that we can try more than one.
-	     */
-	    save_state(&stash))
+	if (save_state(&stash))
 		oidclr(&stash);
 
-	for (i = 0; !merge_was_ok && i < use_strategies_nr; i++) {
+	for (i = 0; i < use_strategies_nr; i++) {
 		int ret, cnt;
 		if (i) {
 			printf(_("Rewinding the tree to pristine...\n"));
@@ -1682,7 +1708,7 @@
 		 */
 		wt_strategy = use_strategies[i]->name;
 
-		ret = try_merge_strategy(use_strategies[i]->name,
+		ret = try_merge_strategy(wt_strategy,
 					 common, remoteheads,
 					 head_commit);
 		/*
@@ -1692,16 +1718,17 @@
 		 */
 		if (ret < 2) {
 			if (!ret) {
-				if (option_commit) {
-					/* Automerge succeeded. */
-					automerge_was_ok = 1;
-					break;
-				}
+				/*
+				 * This strategy worked; no point in trying
+				 * another.
+				 */
 				merge_was_ok = 1;
+				best_strategy = wt_strategy;
+				break;
 			}
 			cnt = (use_strategies_nr > 1) ? evaluate_result() : 0;
 			if (best_cnt <= 0 || cnt <= best_cnt) {
-				best_strategy = use_strategies[i]->name;
+				best_strategy = wt_strategy;
 				best_cnt = cnt;
 			}
 		}
@@ -1711,7 +1738,8 @@
 	 * If we have a resulting tree, that means the strategy module
 	 * auto resolved the merge cleanly.
 	 */
-	if (automerge_was_ok) {
+	if (merge_was_ok && option_commit) {
+		automerge_was_ok = 1;
 		ret = finish_automerge(head_commit, head_subsumed,
 				       common, remoteheads,
 				       &result_tree, wt_strategy);
@@ -1756,6 +1784,8 @@
 			"stopped before committing as requested\n"));
 	else
 		ret = suggest_conflicts();
+	if (autostash)
+		printf(_("When finished, apply stashed changes with `git stash pop`\n"));
 
 done:
 	if (!automerge_was_ok) {
diff --git a/builtin/multi-pack-index.c b/builtin/multi-pack-index.c
index 5edbb7f..9b126d6 100644
--- a/builtin/multi-pack-index.c
+++ b/builtin/multi-pack-index.c
@@ -78,7 +78,7 @@
 }
 
 static int git_multi_pack_index_write_config(const char *var, const char *value,
-					     void *cb)
+					     void *cb UNUSED)
 {
 	if (!strcmp(var, "pack.writebitmaphashcache")) {
 		if (git_config_bool(var, value))
@@ -87,6 +87,13 @@
 			opts.flags &= ~MIDX_WRITE_BITMAP_HASH_CACHE;
 	}
 
+	if (!strcmp(var, "pack.writebitmaplookuptable")) {
+		if (git_config_bool(var, value))
+			opts.flags |= MIDX_WRITE_BITMAP_LOOKUP_TABLE;
+		else
+			opts.flags &= ~MIDX_WRITE_BITMAP_LOOKUP_TABLE;
+	}
+
 	/*
 	 * We should never make a fall-back call to 'git_default_config', since
 	 * this was already called in 'cmd_multi_pack_index()'.
@@ -104,7 +111,8 @@
 	strbuf_release(&buf);
 }
 
-static int cmd_multi_pack_index_write(int argc, const char **argv)
+static int cmd_multi_pack_index_write(int argc, const char **argv,
+				      const char *prefix)
 {
 	struct option *options;
 	static struct option builtin_multi_pack_index_write_options[] = {
@@ -132,9 +140,9 @@
 
 	if (isatty(2))
 		opts.flags |= MIDX_PROGRESS;
-	argc = parse_options(argc, argv, NULL,
+	argc = parse_options(argc, argv, prefix,
 			     options, builtin_multi_pack_index_write_usage,
-			     PARSE_OPT_KEEP_UNKNOWN);
+			     0);
 	if (argc)
 		usage_with_options(builtin_multi_pack_index_write_usage,
 				   options);
@@ -160,7 +168,8 @@
 			       opts.refs_snapshot, opts.flags);
 }
 
-static int cmd_multi_pack_index_verify(int argc, const char **argv)
+static int cmd_multi_pack_index_verify(int argc, const char **argv,
+				       const char *prefix)
 {
 	struct option *options;
 	static struct option builtin_multi_pack_index_verify_options[] = {
@@ -174,9 +183,9 @@
 
 	if (isatty(2))
 		opts.flags |= MIDX_PROGRESS;
-	argc = parse_options(argc, argv, NULL,
+	argc = parse_options(argc, argv, prefix,
 			     options, builtin_multi_pack_index_verify_usage,
-			     PARSE_OPT_KEEP_UNKNOWN);
+			     0);
 	if (argc)
 		usage_with_options(builtin_multi_pack_index_verify_usage,
 				   options);
@@ -186,7 +195,8 @@
 	return verify_midx_file(the_repository, opts.object_dir, opts.flags);
 }
 
-static int cmd_multi_pack_index_expire(int argc, const char **argv)
+static int cmd_multi_pack_index_expire(int argc, const char **argv,
+				       const char *prefix)
 {
 	struct option *options;
 	static struct option builtin_multi_pack_index_expire_options[] = {
@@ -200,9 +210,9 @@
 
 	if (isatty(2))
 		opts.flags |= MIDX_PROGRESS;
-	argc = parse_options(argc, argv, NULL,
+	argc = parse_options(argc, argv, prefix,
 			     options, builtin_multi_pack_index_expire_usage,
-			     PARSE_OPT_KEEP_UNKNOWN);
+			     0);
 	if (argc)
 		usage_with_options(builtin_multi_pack_index_expire_usage,
 				   options);
@@ -212,7 +222,8 @@
 	return expire_midx_packs(the_repository, opts.object_dir, opts.flags);
 }
 
-static int cmd_multi_pack_index_repack(int argc, const char **argv)
+static int cmd_multi_pack_index_repack(int argc, const char **argv,
+				       const char *prefix)
 {
 	struct option *options;
 	static struct option builtin_multi_pack_index_repack_options[] = {
@@ -229,10 +240,10 @@
 
 	if (isatty(2))
 		opts.flags |= MIDX_PROGRESS;
-	argc = parse_options(argc, argv, NULL,
+	argc = parse_options(argc, argv, prefix,
 			     options,
 			     builtin_multi_pack_index_repack_usage,
-			     PARSE_OPT_KEEP_UNKNOWN);
+			     0);
 	if (argc)
 		usage_with_options(builtin_multi_pack_index_repack_usage,
 				   options);
@@ -247,7 +258,15 @@
 			 const char *prefix)
 {
 	int res;
-	struct option *builtin_multi_pack_index_options = common_opts;
+	parse_opt_subcommand_fn *fn = NULL;
+	struct option builtin_multi_pack_index_options[] = {
+		OPT_SUBCOMMAND("repack", &fn, cmd_multi_pack_index_repack),
+		OPT_SUBCOMMAND("write", &fn, cmd_multi_pack_index_write),
+		OPT_SUBCOMMAND("verify", &fn, cmd_multi_pack_index_verify),
+		OPT_SUBCOMMAND("expire", &fn, cmd_multi_pack_index_expire),
+		OPT_END(),
+	};
+	struct option *options = parse_options_concat(builtin_multi_pack_index_options, common_opts);
 
 	git_config(git_default_config, NULL);
 
@@ -256,31 +275,12 @@
 	    the_repository->objects->odb)
 		opts.object_dir = xstrdup(the_repository->objects->odb->path);
 
-	argc = parse_options(argc, argv, prefix,
-			     builtin_multi_pack_index_options,
-			     builtin_multi_pack_index_usage,
-			     PARSE_OPT_STOP_AT_NON_OPTION);
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_multi_pack_index_usage, 0);
+	FREE_AND_NULL(options);
 
-	if (!argc)
-		goto usage;
-
-	if (!strcmp(argv[0], "repack"))
-		res = cmd_multi_pack_index_repack(argc, argv);
-	else if (!strcmp(argv[0], "write"))
-		res =  cmd_multi_pack_index_write(argc, argv);
-	else if (!strcmp(argv[0], "verify"))
-		res =  cmd_multi_pack_index_verify(argc, argv);
-	else if (!strcmp(argv[0], "expire"))
-		res =  cmd_multi_pack_index_expire(argc, argv);
-	else {
-		error(_("unrecognized subcommand: %s"), argv[0]);
-		goto usage;
-	}
+	res = fn(argc, argv, prefix);
 
 	free(opts.object_dir);
 	return res;
-
-usage:
-	usage_with_options(builtin_multi_pack_index_usage,
-			   builtin_multi_pack_index_options);
 }
diff --git a/builtin/mv.c b/builtin/mv.c
index 83a465b..4729bb1 100644
--- a/builtin/mv.c
+++ b/builtin/mv.c
@@ -13,12 +13,21 @@
 #include "string-list.h"
 #include "parse-options.h"
 #include "submodule.h"
+#include "entry.h"
 
 static const char * const builtin_mv_usage[] = {
 	N_("git mv [<options>] <source>... <destination>"),
 	NULL
 };
 
+enum update_mode {
+	BOTH = 0,
+	WORKING_DIRECTORY = (1 << 1),
+	INDEX = (1 << 2),
+	SPARSE = (1 << 3),
+	SKIP_WORKTREE_DIR = (1 << 4),
+};
+
 #define DUP_BASENAME 1
 #define KEEP_TRAILING_SLASH 2
 
@@ -115,6 +124,36 @@
 	return last - first;
 }
 
+/*
+ * Check if an out-of-cone directory should be in the index. Imagine this case
+ * that all the files under a directory are marked with 'CE_SKIP_WORKTREE' bit
+ * and thus the directory is sparsified.
+ *
+ * Return 0 if such directory exist (i.e. with any of its contained files not
+ * marked with CE_SKIP_WORKTREE, the directory would be present in working tree).
+ * Return 1 otherwise.
+ */
+static int check_dir_in_index(const char *name)
+{
+	const char *with_slash = add_slash(name);
+	int length = strlen(with_slash);
+
+	int pos = cache_name_pos(with_slash, length);
+	const struct cache_entry *ce;
+
+	if (pos < 0) {
+		pos = -pos - 1;
+		if (pos >= the_index.cache_nr)
+			return 1;
+		ce = active_cache[pos];
+		if (strncmp(with_slash, ce->name, length))
+			return 1;
+		if (ce_skip_worktree(ce))
+			return 0;
+	}
+	return 1;
+}
+
 int cmd_mv(int argc, const char **argv, const char *prefix)
 {
 	int i, flags, gitmodules_modified = 0;
@@ -129,7 +168,7 @@
 		OPT_END(),
 	};
 	const char **source, **destination, **dest_path, **submodule_gitfile;
-	enum update_mode { BOTH = 0, WORKING_DIRECTORY, INDEX, SPARSE } *modes;
+	enum update_mode *modes;
 	struct stat st;
 	struct string_list src_for_dst = STRING_LIST_INIT_NODUP;
 	struct lock_file lock_file = LOCK_INIT;
@@ -148,7 +187,8 @@
 		die(_("index file corrupt"));
 
 	source = internal_prefix_pathspec(prefix, argv, argc, 0);
-	modes = xcalloc(argc, sizeof(enum update_mode));
+	CALLOC_ARRAY(modes, argc);
+
 	/*
 	 * Keep trailing slash, needed to let
 	 * "git mv file no-such-dir/" error out, except in the case
@@ -176,7 +216,7 @@
 	/* Checking */
 	for (i = 0; i < argc; i++) {
 		const char *src = source[i], *dst = destination[i];
-		int length, src_is_dir;
+		int length;
 		const char *bad = NULL;
 		int skip_sparse = 0;
 
@@ -185,54 +225,103 @@
 
 		length = strlen(src);
 		if (lstat(src, &st) < 0) {
-			/* only error if existence is expected. */
-			if (modes[i] != SPARSE)
+			int pos;
+			const struct cache_entry *ce;
+
+			pos = cache_name_pos(src, length);
+			if (pos < 0) {
+				const char *src_w_slash = add_slash(src);
+				if (!path_in_sparse_checkout(src_w_slash, &the_index) &&
+				    !check_dir_in_index(src)) {
+					modes[i] |= SKIP_WORKTREE_DIR;
+					goto dir_check;
+				}
+				/* only error if existence is expected. */
+				if (!(modes[i] & SPARSE))
+					bad = _("bad source");
+				goto act_on_entry;
+			}
+			ce = active_cache[pos];
+			if (!ce_skip_worktree(ce)) {
 				bad = _("bad source");
-		} else if (!strncmp(src, dst, length) &&
-				(dst[length] == 0 || dst[length] == '/')) {
+				goto act_on_entry;
+			}
+			if (!ignore_sparse) {
+				string_list_append(&only_match_skip_worktree, src);
+				goto act_on_entry;
+			}
+			/* Check if dst exists in index */
+			if (cache_name_pos(dst, strlen(dst)) < 0) {
+				modes[i] |= SPARSE;
+				goto act_on_entry;
+			}
+			if (!force) {
+				bad = _("destination exists");
+				goto act_on_entry;
+			}
+			modes[i] |= SPARSE;
+			goto act_on_entry;
+		}
+		if (!strncmp(src, dst, length) &&
+		    (dst[length] == 0 || dst[length] == '/')) {
 			bad = _("can not move directory into itself");
-		} else if ((src_is_dir = S_ISDIR(st.st_mode))
-				&& lstat(dst, &st) == 0)
+			goto act_on_entry;
+		}
+		if (S_ISDIR(st.st_mode)
+		    && lstat(dst, &st) == 0) {
 			bad = _("cannot move directory over file");
-		else if (src_is_dir) {
+			goto act_on_entry;
+		}
+
+dir_check:
+		if (S_ISDIR(st.st_mode)) {
+			int j, dst_len, n;
 			int first = cache_name_pos(src, length), last;
 
-			if (first >= 0)
+			if (first >= 0) {
 				prepare_move_submodule(src, first,
 						       submodule_gitfile + i);
-			else if (index_range_of_same_dir(src, length,
-							 &first, &last) < 1)
+				goto act_on_entry;
+			} else if (index_range_of_same_dir(src, length,
+							   &first, &last) < 1) {
 				bad = _("source directory is empty");
-			else { /* last - first >= 1 */
-				int j, dst_len, n;
-
-				modes[i] = WORKING_DIRECTORY;
-				n = argc + last - first;
-				REALLOC_ARRAY(source, n);
-				REALLOC_ARRAY(destination, n);
-				REALLOC_ARRAY(modes, n);
-				REALLOC_ARRAY(submodule_gitfile, n);
-
-				dst = add_slash(dst);
-				dst_len = strlen(dst);
-
-				for (j = 0; j < last - first; j++) {
-					const struct cache_entry *ce = active_cache[first + j];
-					const char *path = ce->name;
-					source[argc + j] = path;
-					destination[argc + j] =
-						prefix_path(dst, dst_len, path + length + 1);
-					modes[argc + j] = ce_skip_worktree(ce) ? SPARSE : INDEX;
-					submodule_gitfile[argc + j] = NULL;
-				}
-				argc += last - first;
+				goto act_on_entry;
 			}
-		} else if (!(ce = cache_file_exists(src, length, 0))) {
+
+			/* last - first >= 1 */
+			modes[i] |= WORKING_DIRECTORY;
+			n = argc + last - first;
+			REALLOC_ARRAY(source, n);
+			REALLOC_ARRAY(destination, n);
+			REALLOC_ARRAY(modes, n);
+			REALLOC_ARRAY(submodule_gitfile, n);
+
+			dst = add_slash(dst);
+			dst_len = strlen(dst);
+
+			for (j = 0; j < last - first; j++) {
+				const struct cache_entry *ce = active_cache[first + j];
+				const char *path = ce->name;
+				source[argc + j] = path;
+				destination[argc + j] =
+					prefix_path(dst, dst_len, path + length + 1);
+				memset(modes + argc + j, 0, sizeof(enum update_mode));
+				modes[argc + j] |= ce_skip_worktree(ce) ? SPARSE : INDEX;
+				submodule_gitfile[argc + j] = NULL;
+			}
+			argc += last - first;
+			goto act_on_entry;
+		}
+		if (!(ce = cache_file_exists(src, length, 0))) {
 			bad = _("not under version control");
-		} else if (ce_stage(ce)) {
+			goto act_on_entry;
+		}
+		if (ce_stage(ce)) {
 			bad = _("conflicted");
-		} else if (lstat(dst, &st) == 0 &&
-			 (!ignore_case || strcasecmp(src, dst))) {
+			goto act_on_entry;
+		}
+		if (lstat(dst, &st) == 0 &&
+		    (!ignore_case || strcasecmp(src, dst))) {
 			bad = _("destination exists");
 			if (force) {
 				/*
@@ -246,34 +335,40 @@
 				} else
 					bad = _("Cannot overwrite");
 			}
-		} else if (string_list_has_string(&src_for_dst, dst))
+			goto act_on_entry;
+		}
+		if (string_list_has_string(&src_for_dst, dst)) {
 			bad = _("multiple sources for the same target");
-		else if (is_dir_sep(dst[strlen(dst) - 1]))
+			goto act_on_entry;
+		}
+		if (is_dir_sep(dst[strlen(dst) - 1])) {
 			bad = _("destination directory does not exist");
-		else {
-			/*
-			 * We check if the paths are in the sparse-checkout
-			 * definition as a very final check, since that
-			 * allows us to point the user to the --sparse
-			 * option as a way to have a successful run.
-			 */
-			if (!ignore_sparse &&
-			    !path_in_sparse_checkout(src, &the_index)) {
-				string_list_append(&only_match_skip_worktree, src);
-				skip_sparse = 1;
-			}
-			if (!ignore_sparse &&
-			    !path_in_sparse_checkout(dst, &the_index)) {
-				string_list_append(&only_match_skip_worktree, dst);
-				skip_sparse = 1;
-			}
-
-			if (skip_sparse)
-				goto remove_entry;
-
-			string_list_insert(&src_for_dst, dst);
+			goto act_on_entry;
 		}
 
+		/*
+		 * We check if the paths are in the sparse-checkout
+		 * definition as a very final check, since that
+		 * allows us to point the user to the --sparse
+		 * option as a way to have a successful run.
+		 */
+		if (!ignore_sparse &&
+		    !path_in_sparse_checkout(src, &the_index)) {
+			string_list_append(&only_match_skip_worktree, src);
+			skip_sparse = 1;
+		}
+		if (!ignore_sparse &&
+		    !path_in_sparse_checkout(dst, &the_index)) {
+			string_list_append(&only_match_skip_worktree, dst);
+			skip_sparse = 1;
+		}
+
+		if (skip_sparse)
+			goto remove_entry;
+
+		string_list_insert(&src_for_dst, dst);
+
+act_on_entry:
 		if (!bad)
 			continue;
 		if (!ignore_errors)
@@ -282,14 +377,11 @@
 remove_entry:
 		if (--argc > 0) {
 			int n = argc - i;
-			memmove(source + i, source + i + 1,
-				n * sizeof(char *));
-			memmove(destination + i, destination + i + 1,
-				n * sizeof(char *));
-			memmove(modes + i, modes + i + 1,
-				n * sizeof(enum update_mode));
-			memmove(submodule_gitfile + i, submodule_gitfile + i + 1,
-				n * sizeof(char *));
+			MOVE_ARRAY(source + i, source + i + 1, n);
+			MOVE_ARRAY(destination + i, destination + i + 1, n);
+			MOVE_ARRAY(modes + i, modes + i + 1, n);
+			MOVE_ARRAY(submodule_gitfile + i,
+				   submodule_gitfile + i + 1, n);
 			i--;
 		}
 	}
@@ -304,11 +396,17 @@
 		const char *src = source[i], *dst = destination[i];
 		enum update_mode mode = modes[i];
 		int pos;
+		struct checkout state = CHECKOUT_INIT;
+		state.istate = &the_index;
+
+		if (force)
+			state.force = 1;
 		if (show_only || verbose)
 			printf(_("Renaming %s to %s\n"), src, dst);
 		if (show_only)
 			continue;
-		if (mode != INDEX && mode != SPARSE && rename(src, dst) < 0) {
+		if (!(mode & (INDEX | SPARSE | SKIP_WORKTREE_DIR)) &&
+		    rename(src, dst) < 0) {
 			if (ignore_errors)
 				continue;
 			die_errno(_("renaming '%s' failed"), src);
@@ -322,12 +420,23 @@
 							      1);
 		}
 
-		if (mode == WORKING_DIRECTORY)
+		if (mode & (WORKING_DIRECTORY | SKIP_WORKTREE_DIR))
 			continue;
 
 		pos = cache_name_pos(src, strlen(src));
 		assert(pos >= 0);
 		rename_cache_entry_at(pos, dst);
+
+		if ((mode & SPARSE) &&
+		    (path_in_sparse_checkout(dst, &the_index))) {
+			int dst_pos;
+
+			dst_pos = cache_name_pos(dst, strlen(dst));
+			active_cache[dst_pos]->ce_flags &= ~CE_SKIP_WORKTREE;
+
+			if (checkout_entry(active_cache[dst_pos], &state, NULL, NULL))
+				die(_("cannot checkout %s"), active_cache[dst_pos]->name);
+		}
 	}
 
 	if (gitmodules_modified)
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index 580b1eb..15535e9 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -344,7 +344,8 @@
 	return a->taggerdate != b->taggerdate;
 }
 
-static int name_ref(const char *path, const struct object_id *oid, int flags, void *cb_data)
+static int name_ref(const char *path, const struct object_id *oid,
+		    int flags UNUSED, void *cb_data)
 {
 	struct object *o = parse_object(the_repository, oid);
 	struct name_ref_data *data = cb_data;
diff --git a/builtin/notes.c b/builtin/notes.c
index a3d0d15..be51f69 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -994,17 +994,34 @@
 
 int cmd_notes(int argc, const char **argv, const char *prefix)
 {
-	int result;
 	const char *override_notes_ref = NULL;
+	parse_opt_subcommand_fn *fn = NULL;
 	struct option options[] = {
 		OPT_STRING(0, "ref", &override_notes_ref, N_("notes-ref"),
 			   N_("use notes from <notes-ref>")),
+		OPT_SUBCOMMAND("list", &fn, list),
+		OPT_SUBCOMMAND("add", &fn, add),
+		OPT_SUBCOMMAND("copy", &fn, copy),
+		OPT_SUBCOMMAND("append", &fn, append_edit),
+		OPT_SUBCOMMAND("edit", &fn, append_edit),
+		OPT_SUBCOMMAND("show", &fn, show),
+		OPT_SUBCOMMAND("merge", &fn, merge),
+		OPT_SUBCOMMAND("remove", &fn, remove_cmd),
+		OPT_SUBCOMMAND("prune", &fn, prune),
+		OPT_SUBCOMMAND("get-ref", &fn, get_ref),
 		OPT_END()
 	};
 
 	git_config(git_default_config, NULL);
 	argc = parse_options(argc, argv, prefix, options, git_notes_usage,
-			     PARSE_OPT_STOP_AT_NON_OPTION);
+			     PARSE_OPT_SUBCOMMAND_OPTIONAL);
+	if (!fn) {
+		if (argc) {
+			error(_("unknown subcommand: `%s'"), argv[0]);
+			usage_with_options(git_notes_usage, options);
+		}
+		fn = list;
+	}
 
 	if (override_notes_ref) {
 		struct strbuf sb = STRBUF_INIT;
@@ -1014,28 +1031,5 @@
 		strbuf_release(&sb);
 	}
 
-	if (argc < 1 || !strcmp(argv[0], "list"))
-		result = list(argc, argv, prefix);
-	else if (!strcmp(argv[0], "add"))
-		result = add(argc, argv, prefix);
-	else if (!strcmp(argv[0], "copy"))
-		result = copy(argc, argv, prefix);
-	else if (!strcmp(argv[0], "append") || !strcmp(argv[0], "edit"))
-		result = append_edit(argc, argv, prefix);
-	else if (!strcmp(argv[0], "show"))
-		result = show(argc, argv, prefix);
-	else if (!strcmp(argv[0], "merge"))
-		result = merge(argc, argv, prefix);
-	else if (!strcmp(argv[0], "remove"))
-		result = remove_cmd(argc, argv, prefix);
-	else if (!strcmp(argv[0], "prune"))
-		result = prune(argc, argv, prefix);
-	else if (!strcmp(argv[0], "get-ref"))
-		result = get_ref(argc, argv, prefix);
-	else {
-		result = error(_("unknown subcommand: %s"), argv[0]);
-		usage_with_options(git_notes_usage, options);
-	}
-
-	return result ? 1 : 0;
+	return !!fn(argc, argv, prefix);
 }
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 39e28cf..3658c05 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -759,8 +759,8 @@
 	return WRITE_ONE_WRITTEN;
 }
 
-static int mark_tagged(const char *path, const struct object_id *oid, int flag,
-		       void *cb_data)
+static int mark_tagged(const char *path UNUSED, const struct object_id *oid,
+		       int flag UNUSED, void *cb_data UNUSED)
 {
 	struct object_id peeled;
 	struct object_entry *entry = packlist_find(&to_pack, oid);
@@ -3035,7 +3035,8 @@
 	}
 }
 
-static int add_ref_tag(const char *tag, const struct object_id *oid, int flag, void *cb_data)
+static int add_ref_tag(const char *tag UNUSED, const struct object_id *oid,
+		       int flag UNUSED, void *cb_data UNUSED)
 {
 	struct object_id peeled;
 
@@ -3148,6 +3149,14 @@
 		else
 			write_bitmap_options &= ~BITMAP_OPT_HASH_CACHE;
 	}
+
+	if (!strcmp(k, "pack.writebitmaplookuptable")) {
+		if (git_config_bool(k, v))
+			write_bitmap_options |= BITMAP_OPT_LOOKUP_TABLE;
+		else
+			write_bitmap_options &= ~BITMAP_OPT_LOOKUP_TABLE;
+	}
+
 	if (!strcmp(k, "pack.usebitmaps")) {
 		use_bitmap_index_default = git_config_bool(k, v);
 		return 0;
@@ -3950,8 +3959,9 @@
 }
 
 static int mark_bitmap_preferred_tip(const char *refname,
-				     const struct object_id *oid, int flags,
-				     void *_data)
+				     const struct object_id *oid,
+				     int flags UNUSED,
+				     void *data UNUSED)
 {
 	struct object_id peeled;
 	struct object *object;
diff --git a/builtin/pull.c b/builtin/pull.c
index 01155ba..403a24d 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -990,6 +990,7 @@
 	int rebase_unspecified = 0;
 	int can_ff;
 	int divergent;
+	int ret;
 
 	if (!getenv("GIT_REFLOG_ACTION"))
 		set_reflog_message(argc, argv);
@@ -1100,7 +1101,8 @@
 	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.oid, &curr_head);
+		ret = pull_into_void(merge_heads.oid, &curr_head);
+		goto cleanup;
 	}
 	if (merge_heads.nr > 1) {
 		if (opt_rebase)
@@ -1125,8 +1127,6 @@
 	}
 
 	if (opt_rebase) {
-		int ret = 0;
-
 		struct object_id newbase;
 		struct object_id upstream;
 		get_rebase_newbase_and_upstream(&newbase, &upstream, &curr_head,
@@ -1149,12 +1149,16 @@
 			     recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND))
 			ret = rebase_submodules();
 
-		return ret;
+		goto cleanup;
 	} else {
-		int ret = run_merge();
+		ret = run_merge();
 		if (!ret && (recurse_submodules == RECURSE_SUBMODULES_ON ||
 			     recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND))
 			ret = update_submodules();
-		return ret;
+		goto cleanup;
 	}
+
+cleanup:
+	oid_array_clear(&merge_heads);
+	return ret;
 }
diff --git a/builtin/range-diff.c b/builtin/range-diff.c
index 5031884..e2a74ef 100644
--- a/builtin/range-diff.c
+++ b/builtin/range-diff.c
@@ -38,8 +38,10 @@
 		OPT_END()
 	};
 	struct option *options;
-	int res = 0;
+	int i, dash_dash = -1, res = 0;
 	struct strbuf range1 = STRBUF_INIT, range2 = STRBUF_INIT;
+	struct object_id oid;
+	const char *three_dots = NULL;
 
 	git_config(git_diff_ui_config, NULL);
 
@@ -47,7 +49,7 @@
 
 	options = parse_options_concat(range_diff_options, diffopt.parseopts);
 	argc = parse_options(argc, argv, prefix, options,
-			     builtin_range_diff_usage, 0);
+			     builtin_range_diff_usage, PARSE_OPT_KEEP_DASHDASH);
 
 	diff_setup_done(&diffopt);
 
@@ -55,40 +57,91 @@
 	if (!simple_color)
 		diffopt.use_color = 1;
 
-	if (argc == 2) {
-		if (!is_range_diff_range(argv[0]))
-			die(_("not a commit range: '%s'"), argv[0]);
-		strbuf_addstr(&range1, argv[0]);
+	for (i = 0; i < argc; i++)
+		if (!strcmp(argv[i], "--")) {
+			dash_dash = i;
+			break;
+		}
 
-		if (!is_range_diff_range(argv[1]))
-			die(_("not a commit range: '%s'"), argv[1]);
-		strbuf_addstr(&range2, argv[1]);
-	} else if (argc == 3) {
+	if (dash_dash == 3 ||
+	    (dash_dash < 0 && argc > 2 &&
+	     !get_oid_committish(argv[0], &oid) &&
+	     !get_oid_committish(argv[1], &oid) &&
+	     !get_oid_committish(argv[2], &oid))) {
+		if (dash_dash < 0)
+			; /* already validated arguments */
+		else if (get_oid_committish(argv[0], &oid))
+			usage_msg_optf(_("not a revision: '%s'"),
+				       builtin_range_diff_usage, options,
+				       argv[0]);
+		else if (get_oid_committish(argv[1], &oid))
+			usage_msg_optf(_("not a revision: '%s'"),
+				       builtin_range_diff_usage, options,
+				       argv[1]);
+		else if (get_oid_committish(argv[2], &oid))
+			usage_msg_optf(_("not a revision: '%s'"),
+				       builtin_range_diff_usage, options,
+				       argv[2]);
+
 		strbuf_addf(&range1, "%s..%s", argv[0], argv[1]);
 		strbuf_addf(&range2, "%s..%s", argv[0], argv[2]);
-	} else if (argc == 1) {
-		const char *b = strstr(argv[0], "..."), *a = argv[0];
+
+		strvec_pushv(&other_arg, argv +
+			     (dash_dash < 0 ? 3 : dash_dash));
+	} else if (dash_dash == 2 ||
+		   (dash_dash < 0 && argc > 1 &&
+		    is_range_diff_range(argv[0]) &&
+		    is_range_diff_range(argv[1]))) {
+		if (dash_dash < 0)
+			; /* already validated arguments */
+		else if (!is_range_diff_range(argv[0]))
+			usage_msg_optf(_("not a commit range: '%s'"),
+				       builtin_range_diff_usage, options,
+				       argv[0]);
+		else if (!is_range_diff_range(argv[1]))
+			usage_msg_optf(_("not a commit range: '%s'"),
+				       builtin_range_diff_usage, options,
+				       argv[1]);
+
+		strbuf_addstr(&range1, argv[0]);
+		strbuf_addstr(&range2, argv[1]);
+
+		strvec_pushv(&other_arg, argv +
+			     (dash_dash < 0 ? 2 : dash_dash));
+	} else if (dash_dash == 1 ||
+		   (dash_dash < 0 && argc > 0 &&
+		    (three_dots = strstr(argv[0], "...")))) {
+		const char *a, *b;
 		int a_len;
 
-		if (!b) {
-			error(_("single arg format must be symmetric range"));
-			usage_with_options(builtin_range_diff_usage, options);
-		}
+		if (dash_dash < 0)
+			; /* already validated arguments */
+		else if (!(three_dots = strstr(argv[0], "...")))
+			usage_msg_optf(_("not a symmetric range: '%s'"),
+					 builtin_range_diff_usage, options,
+					 argv[0]);
 
-		a_len = (int)(b - a);
-		if (!a_len) {
+		if (three_dots == argv[0]) {
 			a = "HEAD";
 			a_len = strlen(a);
+		} else {
+			a = argv[0];
+			a_len = (int)(three_dots - a);
 		}
-		b += 3;
-		if (!*b)
+
+		if (three_dots[3])
+			b = three_dots + 3;
+		else
 			b = "HEAD";
+
 		strbuf_addf(&range1, "%s..%.*s", b, a_len, a);
 		strbuf_addf(&range2, "%.*s..%s", a_len, a, b);
-	} else {
-		error(_("need two commit ranges"));
-		usage_with_options(builtin_range_diff_usage, options);
-	}
+
+		strvec_pushv(&other_arg, argv +
+			     (dash_dash < 0 ? 1 : dash_dash));
+	} else
+		usage_msg_opt(_("need two commit ranges"),
+			      builtin_range_diff_usage, options);
 	FREE_AND_NULL(options);
 
 	range_diff_opts.dual_color = simple_color < 1;
diff --git a/builtin/rebase.c b/builtin/rebase.c
index 70aa7c8..56e4214 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -102,6 +102,7 @@
 	int reschedule_failed_exec;
 	int reapply_cherry_picks;
 	int fork_point;
+	int update_refs;
 };
 
 #define REBASE_OPTIONS_INIT {			  	\
@@ -298,6 +299,7 @@
 		ret = complete_action(the_repository, &replay, flags,
 			shortrevisions, opts->onto_name, opts->onto,
 			&opts->orig_head, &commands, opts->autosquash,
+			opts->update_refs,
 			&todo_list);
 	}
 
@@ -800,6 +802,11 @@
 		return 0;
 	}
 
+	if (!strcmp(var, "rebase.updaterefs")) {
+		opts->update_refs = git_config_bool(var, value);
+		return 0;
+	}
+
 	if (!strcmp(var, "rebase.reschedulefailedexec")) {
 		opts->reschedule_failed_exec = git_config_bool(var, value);
 		return 0;
@@ -1124,6 +1131,9 @@
 		OPT_BOOL(0, "autosquash", &options.autosquash,
 			 N_("move commits that begin with "
 			    "squash!/fixup! under -i")),
+		OPT_BOOL(0, "update-refs", &options.update_refs,
+			 N_("update branches that point to commits "
+			    "that are being rebased")),
 		{ OPTION_STRING, 'S', "gpg-sign", &gpg_sign, N_("key-id"),
 			N_("GPG-sign commits"),
 			PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 31b48e7..44bcea3 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -291,7 +291,7 @@
 }
 
 static int show_ref_cb(const char *path_full, const struct object_id *oid,
-		       int flag, void *data)
+		       int flag UNUSED, void *data)
 {
 	struct oidset *seen = data;
 	const char *path = strip_namespace(path_full);
@@ -465,7 +465,7 @@
 	va_end(params);
 }
 
-static int copy_to_sideband(int in, int out, void *arg)
+static int copy_to_sideband(int in, int out UNUSED, void *arg UNUSED)
 {
 	char data[128];
 	int keepalive_active = 0;
diff --git a/builtin/reflog.c b/builtin/reflog.c
index 4dd297d..57c5c0d 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -56,7 +56,8 @@
 	struct string_list reflogs;
 };
 
-static int collect_reflog(const char *ref, const struct object_id *oid, int unused, void *cb_data)
+static int collect_reflog(const char *ref, const struct object_id *oid UNUSED,
+			  int flags UNUSED, void *cb_data)
 {
 	struct worktree_reflogs *cb = cb_data;
 	struct worktree *worktree = cb->worktree;
@@ -193,6 +194,8 @@
 {
 	struct cmd_reflog_expire_cb *cmd = opt->value;
 
+	BUG_ON_OPT_NEG(unset);
+
 	if (parse_expiry_date(arg, &cmd->expire_unreachable))
 		die(_("invalid timestamp '%s' given to '--%s'"),
 		    arg, opt->long_name);
@@ -207,6 +210,8 @@
 {
 	struct cmd_reflog_expire_cb *cmd = opt->value;
 
+	BUG_ON_OPT_NEG(unset);
+
 	if (parse_expiry_date(arg, &cmd->expire_total))
 		die(_("invalid timestamp '%s' given to '--%s'"),
 		    arg, opt->long_name);
@@ -223,7 +228,7 @@
 
 	parse_options(argc, argv, prefix, options, reflog_show_usage,
 		      PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_ARGV0 |
-		      PARSE_OPT_KEEP_UNKNOWN);
+		      PARSE_OPT_KEEP_UNKNOWN_OPT);
 
 	return cmd_log_reflog(argc, argv, prefix);
 }
@@ -404,40 +409,21 @@
 
 int cmd_reflog(int argc, const char **argv, const char *prefix)
 {
+	parse_opt_subcommand_fn *fn = NULL;
 	struct option options[] = {
+		OPT_SUBCOMMAND("show", &fn, cmd_reflog_show),
+		OPT_SUBCOMMAND("expire", &fn, cmd_reflog_expire),
+		OPT_SUBCOMMAND("delete", &fn, cmd_reflog_delete),
+		OPT_SUBCOMMAND("exists", &fn, cmd_reflog_exists),
 		OPT_END()
 	};
 
 	argc = parse_options(argc, argv, prefix, options, reflog_usage,
+			     PARSE_OPT_SUBCOMMAND_OPTIONAL |
 			     PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_ARGV0 |
-			     PARSE_OPT_KEEP_UNKNOWN |
-			     PARSE_OPT_NO_INTERNAL_HELP);
-
-	/*
-	 * With "git reflog" we default to showing it. !argc is
-	 * impossible with PARSE_OPT_KEEP_ARGV0.
-	 */
-	if (argc == 1)
-		goto log_reflog;
-
-	if (!strcmp(argv[1], "-h"))
-		usage_with_options(reflog_usage, options);
-	else if (*argv[1] == '-')
-		goto log_reflog;
-
-	if (!strcmp(argv[1], "show"))
-		return cmd_reflog_show(argc - 1, argv + 1, prefix);
-	else if (!strcmp(argv[1], "expire"))
-		return cmd_reflog_expire(argc - 1, argv + 1, prefix);
-	else if (!strcmp(argv[1], "delete"))
-		return cmd_reflog_delete(argc - 1, argv + 1, prefix);
-	else if (!strcmp(argv[1], "exists"))
-		return cmd_reflog_exists(argc - 1, argv + 1, prefix);
-
-	/*
-	 * Fall-through for e.g. "git reflog -1", "git reflog master",
-	 * as well as the plain "git reflog" above goto above.
-	 */
-log_reflog:
-	return cmd_log_reflog(argc, argv, prefix);
+			     PARSE_OPT_KEEP_UNKNOWN_OPT);
+	if (fn)
+		return fn(argc - 1, argv + 1, prefix);
+	else
+		return cmd_log_reflog(argc, argv, prefix);
 }
diff --git a/builtin/remote.c b/builtin/remote.c
index a3a0c27..985b845 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -150,7 +150,7 @@
 	return 0;
 }
 
-static int add(int argc, const char **argv)
+static int add(int argc, const char **argv, const char *prefix)
 {
 	int fetch = 0, fetch_tags = TAGS_DEFAULT;
 	unsigned mirror = MIRROR_NONE;
@@ -177,8 +177,8 @@
 		OPT_END()
 	};
 
-	argc = parse_options(argc, argv, NULL, options, builtin_remote_add_usage,
-			     0);
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_remote_add_usage, 0);
 
 	if (argc != 2)
 		usage_with_options(builtin_remote_add_usage, options);
@@ -264,7 +264,8 @@
 }
 #define abbrev_branch(name) abbrev_ref((name), "refs/heads/")
 
-static int config_read_branches(const char *key, const char *value, void *cb)
+static int config_read_branches(const char *key, const char *value,
+				void *data UNUSED)
 {
 	const char *orig_key = key;
 	char *name;
@@ -344,12 +345,13 @@
 
 struct ref_states {
 	struct remote *remote;
-	struct string_list new_refs, stale, tracked, heads, push;
+	struct string_list new_refs, skipped, stale, tracked, heads, push;
 	int queried;
 };
 
 #define REF_STATES_INIT { \
 	.new_refs = STRING_LIST_INIT_DUP, \
+	.skipped = STRING_LIST_INIT_DUP, \
 	.stale = STRING_LIST_INIT_DUP, \
 	.tracked = STRING_LIST_INIT_DUP, \
 	.heads = STRING_LIST_INIT_DUP, \
@@ -368,7 +370,9 @@
 				states->remote->fetch.raw[i]);
 
 	for (ref = fetch_map; ref; ref = ref->next) {
-		if (!ref->peer_ref || !ref_exists(ref->peer_ref->name))
+		if (omit_name_by_refspec(ref->name, &states->remote->fetch))
+			string_list_append(&states->skipped, abbrev_branch(ref->name));
+		else if (!ref->peer_ref || !ref_exists(ref->peer_ref->name))
 			string_list_append(&states->new_refs, abbrev_branch(ref->name));
 		else
 			string_list_append(&states->tracked, abbrev_branch(ref->name));
@@ -383,6 +387,7 @@
 	free_refs(fetch_map);
 
 	string_list_sort(&states->new_refs);
+	string_list_sort(&states->skipped);
 	string_list_sort(&states->tracked);
 	string_list_sort(&states->stale);
 
@@ -534,7 +539,8 @@
 };
 
 static int add_branch_for_removal(const char *refname,
-	const struct object_id *oid, int flags, void *cb_data)
+				  const struct object_id *oid UNUSED,
+				  int flags UNUSED, void *cb_data)
 {
 	struct branches_for_remote *branches = cb_data;
 	struct refspec_item refspec;
@@ -576,7 +582,8 @@
 };
 
 static int read_remote_branches(const char *refname,
-	const struct object_id *oid, int flags, void *cb_data)
+				const struct object_id *oid UNUSED,
+				int flags UNUSED, void *cb_data)
 {
 	struct rename_info *rename = cb_data;
 	struct strbuf buf = STRBUF_INIT;
@@ -676,7 +683,7 @@
 }
 
 
-static int mv(int argc, const char **argv)
+static int mv(int argc, const char **argv, const char *prefix)
 {
 	int show_progress = isatty(2);
 	struct option options[] = {
@@ -691,7 +698,7 @@
 	int i, refs_renamed_nr = 0, refspec_updated = 0;
 	struct progress *progress = NULL;
 
-	argc = parse_options(argc, argv, NULL, options,
+	argc = parse_options(argc, argv, prefix, options,
 			     builtin_remote_rename_usage, 0);
 
 	if (argc != 2)
@@ -840,7 +847,7 @@
 	return 0;
 }
 
-static int rm(int argc, const char **argv)
+static int rm(int argc, const char **argv, const char *prefix)
 {
 	struct option options[] = {
 		OPT_END()
@@ -858,12 +865,14 @@
 	cb_data.skipped = &skipped;
 	cb_data.keep = &known_remotes;
 
-	if (argc != 2)
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_remote_rm_usage, 0);
+	if (argc != 1)
 		usage_with_options(builtin_remote_rm_usage, options);
 
-	remote = remote_get(argv[1]);
+	remote = remote_get(argv[0]);
 	if (!remote_is_configured(remote, 1)) {
-		error(_("No such remote: '%s'"), argv[1]);
+		error(_("No such remote: '%s'"), argv[0]);
 		exit(2);
 	}
 
@@ -941,6 +950,7 @@
 static void free_remote_ref_states(struct ref_states *states)
 {
 	string_list_clear(&states->new_refs, 0);
+	string_list_clear(&states->skipped, 0);
 	string_list_clear(&states->stale, 1);
 	string_list_clear(&states->tracked, 0);
 	string_list_clear(&states->heads, 0);
@@ -948,7 +958,8 @@
 }
 
 static int append_ref_to_tracked_list(const char *refname,
-	const struct object_id *oid, int flags, void *cb_data)
+				      const struct object_id *oid UNUSED,
+				      int flags, void *cb_data)
 {
 	struct ref_states *states = cb_data;
 	struct refspec_item refspec;
@@ -1035,6 +1046,8 @@
 			arg = states->remote->name;
 		} else if (string_list_has_string(&states->tracked, name))
 			arg = _(" tracked");
+		else if (string_list_has_string(&states->skipped, name))
+			arg = _(" skipped");
 		else if (string_list_has_string(&states->stale, name))
 			arg = _(" stale (use 'git remote prune' to remove)");
 		else
@@ -1247,7 +1260,7 @@
 	return result;
 }
 
-static int show(int argc, const char **argv)
+static int show(int argc, const char **argv, const char *prefix)
 {
 	int no_query = 0, result = 0, query_flag = 0;
 	struct option options[] = {
@@ -1256,7 +1269,8 @@
 	};
 	struct show_info info = SHOW_INFO_INIT;
 
-	argc = parse_options(argc, argv, NULL, options, builtin_remote_show_usage,
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_remote_show_usage,
 			     0);
 
 	if (argc < 1)
@@ -1307,6 +1321,7 @@
 		/* remote branch info */
 		info.width = 0;
 		for_each_string_list(&info.states.new_refs, add_remote_to_show_info, &info);
+		for_each_string_list(&info.states.skipped, add_remote_to_show_info, &info);
 		for_each_string_list(&info.states.tracked, add_remote_to_show_info, &info);
 		for_each_string_list(&info.states.stale, add_remote_to_show_info, &info);
 		if (info.list.nr)
@@ -1349,7 +1364,7 @@
 	return result;
 }
 
-static int set_head(int argc, const char **argv)
+static int set_head(int argc, const char **argv, const char *prefix)
 {
 	int i, opt_a = 0, opt_d = 0, result = 0;
 	struct strbuf buf = STRBUF_INIT, buf2 = STRBUF_INIT;
@@ -1362,8 +1377,8 @@
 			 N_("delete refs/remotes/<name>/HEAD")),
 		OPT_END()
 	};
-	argc = parse_options(argc, argv, NULL, options, builtin_remote_sethead_usage,
-			     0);
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_remote_sethead_usage, 0);
 	if (argc)
 		strbuf_addf(&buf, "refs/remotes/%s/HEAD", argv[0]);
 
@@ -1454,7 +1469,7 @@
 	return result;
 }
 
-static int prune(int argc, const char **argv)
+static int prune(int argc, const char **argv, const char *prefix)
 {
 	int dry_run = 0, result = 0;
 	struct option options[] = {
@@ -1462,8 +1477,8 @@
 		OPT_END()
 	};
 
-	argc = parse_options(argc, argv, NULL, options, builtin_remote_prune_usage,
-			     0);
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_remote_prune_usage, 0);
 
 	if (argc < 1)
 		usage_with_options(builtin_remote_prune_usage, options);
@@ -1474,7 +1489,7 @@
 	return result;
 }
 
-static int get_remote_default(const char *key, const char *value, void *priv)
+static int get_remote_default(const char *key, const char *value UNUSED, void *priv)
 {
 	if (strcmp(key, "remotes.default") == 0) {
 		int *found = priv;
@@ -1483,7 +1498,7 @@
 	return 0;
 }
 
-static int update(int argc, const char **argv)
+static int update(int argc, const char **argv, const char *prefix)
 {
 	int i, prune = -1;
 	struct option options[] = {
@@ -1495,7 +1510,8 @@
 	int default_defined = 0;
 	int retval;
 
-	argc = parse_options(argc, argv, NULL, options, builtin_remote_update_usage,
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_remote_update_usage,
 			     PARSE_OPT_KEEP_ARGV0);
 
 	strvec_push(&fetch_argv, "fetch");
@@ -1566,7 +1582,7 @@
 	return 0;
 }
 
-static int set_branches(int argc, const char **argv)
+static int set_branches(int argc, const char **argv, const char *prefix)
 {
 	int add_mode = 0;
 	struct option options[] = {
@@ -1574,7 +1590,7 @@
 		OPT_END()
 	};
 
-	argc = parse_options(argc, argv, NULL, options,
+	argc = parse_options(argc, argv, prefix, options,
 			     builtin_remote_setbranches_usage, 0);
 	if (argc == 0) {
 		error(_("no remote specified"));
@@ -1585,7 +1601,7 @@
 	return set_remote_branches(argv[0], argv + 1, add_mode);
 }
 
-static int get_url(int argc, const char **argv)
+static int get_url(int argc, const char **argv, const char *prefix)
 {
 	int i, push_mode = 0, all_mode = 0;
 	const char *remotename = NULL;
@@ -1599,7 +1615,8 @@
 			 N_("return all URLs")),
 		OPT_END()
 	};
-	argc = parse_options(argc, argv, NULL, options, builtin_remote_geturl_usage, 0);
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_remote_geturl_usage, 0);
 
 	if (argc != 1)
 		usage_with_options(builtin_remote_geturl_usage, options);
@@ -1638,7 +1655,7 @@
 	return 0;
 }
 
-static int set_url(int argc, const char **argv)
+static int set_url(int argc, const char **argv, const char *prefix)
 {
 	int i, push_mode = 0, add_mode = 0, delete_mode = 0;
 	int matches = 0, negative_matches = 0;
@@ -1659,7 +1676,8 @@
 			    N_("delete URLs")),
 		OPT_END()
 	};
-	argc = parse_options(argc, argv, NULL, options, builtin_remote_seturl_usage,
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_remote_seturl_usage,
 			     PARSE_OPT_KEEP_ARGV0);
 
 	if (add_mode && delete_mode)
@@ -1730,41 +1748,33 @@
 
 int cmd_remote(int argc, const char **argv, const char *prefix)
 {
+	parse_opt_subcommand_fn *fn = NULL;
 	struct option options[] = {
 		OPT__VERBOSE(&verbose, N_("be verbose; must be placed before a subcommand")),
+		OPT_SUBCOMMAND("add", &fn, add),
+		OPT_SUBCOMMAND("rename", &fn, mv),
+		OPT_SUBCOMMAND_F("rm", &fn, rm, PARSE_OPT_NOCOMPLETE),
+		OPT_SUBCOMMAND("remove", &fn, rm),
+		OPT_SUBCOMMAND("set-head", &fn, set_head),
+		OPT_SUBCOMMAND("set-branches", &fn, set_branches),
+		OPT_SUBCOMMAND("get-url", &fn, get_url),
+		OPT_SUBCOMMAND("set-url", &fn, set_url),
+		OPT_SUBCOMMAND("show", &fn, show),
+		OPT_SUBCOMMAND("prune", &fn, prune),
+		OPT_SUBCOMMAND("update", &fn, update),
 		OPT_END()
 	};
-	int result;
 
 	argc = parse_options(argc, argv, prefix, options, builtin_remote_usage,
-		PARSE_OPT_STOP_AT_NON_OPTION);
+			     PARSE_OPT_SUBCOMMAND_OPTIONAL);
 
-	if (argc < 1)
-		result = show_all();
-	else if (!strcmp(argv[0], "add"))
-		result = add(argc, argv);
-	else if (!strcmp(argv[0], "rename"))
-		result = mv(argc, argv);
-	else if (!strcmp(argv[0], "rm") || !strcmp(argv[0], "remove"))
-		result = rm(argc, argv);
-	else if (!strcmp(argv[0], "set-head"))
-		result = set_head(argc, argv);
-	else if (!strcmp(argv[0], "set-branches"))
-		result = set_branches(argc, argv);
-	else if (!strcmp(argv[0], "get-url"))
-		result = get_url(argc, argv);
-	else if (!strcmp(argv[0], "set-url"))
-		result = set_url(argc, argv);
-	else if (!strcmp(argv[0], "show"))
-		result = show(argc, argv);
-	else if (!strcmp(argv[0], "prune"))
-		result = prune(argc, argv);
-	else if (!strcmp(argv[0], "update"))
-		result = update(argc, argv);
-	else {
-		error(_("Unknown subcommand: %s"), argv[0]);
-		usage_with_options(builtin_remote_usage, options);
+	if (fn) {
+		return !!fn(argc, argv, prefix);
+	} else {
+		if (argc) {
+			error(_("unknown subcommand: `%s'"), argv[0]);
+			usage_with_options(builtin_remote_usage, options);
+		}
+		return !!show_all();
 	}
-
-	return result ? 1 : 0;
 }
diff --git a/builtin/repack.c b/builtin/repack.c
index 4a7ae4c..a5bacc7 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -514,9 +514,9 @@
 	int preferred;
 };
 
-static int midx_snapshot_ref_one(const char *refname,
+static int midx_snapshot_ref_one(const char *refname UNUSED,
 				 const struct object_id *oid,
-				 int flag, void *_data)
+				 int flag UNUSED, void *_data)
 {
 	struct midx_snapshot_ref_data *data = _data;
 	struct object_id peeled;
@@ -727,7 +727,6 @@
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	struct string_list_item *item;
 	struct string_list names = STRING_LIST_INIT_DUP;
-	struct string_list rollback = STRING_LIST_INIT_NODUP;
 	struct string_list existing_nonkept_packs = STRING_LIST_INIT_DUP;
 	struct string_list existing_kept_packs = STRING_LIST_INIT_DUP;
 	struct pack_geometry *geometry = NULL;
@@ -1117,7 +1116,6 @@
 	}
 
 	string_list_clear(&names, 0);
-	string_list_clear(&rollback, 0);
 	string_list_clear(&existing_nonkept_packs, 0);
 	string_list_clear(&existing_kept_packs, 0);
 	clear_pack_geometry(geometry);
diff --git a/builtin/replace.c b/builtin/replace.c
index 583702a..a29e911 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -106,6 +106,7 @@
 	size_t base_len;
 	int had_error = 0;
 	struct object_id oid;
+	const char *git_replace_ref_base = ref_namespace[NAMESPACE_REPLACE].ref;
 
 	strbuf_addstr(&ref, git_replace_ref_base);
 	base_len = ref.len;
@@ -147,6 +148,8 @@
 			    struct strbuf *ref,
 			    int force)
 {
+	const char *git_replace_ref_base = ref_namespace[NAMESPACE_REPLACE].ref;
+
 	strbuf_reset(ref);
 	strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
 	if (check_refname_format(ref->buf, 0))
diff --git a/builtin/reset.c b/builtin/reset.c
index 344fff8..fdce6f8 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -174,88 +174,6 @@
 	}
 }
 
-static int pathspec_needs_expanded_index(const struct pathspec *pathspec)
-{
-	unsigned int i, pos;
-	int res = 0;
-	char *skip_worktree_seen = NULL;
-
-	/*
-	 * When using a magic pathspec, assume for the sake of simplicity that
-	 * the index needs to be expanded to match all matchable files.
-	 */
-	if (pathspec->magic)
-		return 1;
-
-	for (i = 0; i < pathspec->nr; i++) {
-		struct pathspec_item item = pathspec->items[i];
-
-		/*
-		 * If the pathspec item has a wildcard, the index should be expanded
-		 * if the pathspec has the possibility of matching a subset of entries inside
-		 * of a sparse directory (but not the entire directory).
-		 *
-		 * If the pathspec item is a literal path, the index only needs to be expanded
-		 * if a) the pathspec isn't in the sparse checkout cone (to make sure we don't
-		 * expand for in-cone files) and b) it doesn't match any sparse directories
-		 * (since we can reset whole sparse directories without expanding them).
-		 */
-		if (item.nowildcard_len < item.len) {
-			/*
-			 * Special case: if the pattern is a path inside the cone
-			 * followed by only wildcards, the pattern cannot match
-			 * partial sparse directories, so we know we don't need to
-			 * expand the index.
-			 *
-			 * Examples:
-			 * - in-cone/foo***: doesn't need expanded index
-			 * - not-in-cone/bar*: may need expanded index
-			 * - **.c: may need expanded index
-			 */
-			if (strspn(item.original + item.nowildcard_len, "*") == item.len - item.nowildcard_len &&
-			    path_in_cone_mode_sparse_checkout(item.original, &the_index))
-				continue;
-
-			for (pos = 0; pos < active_nr; pos++) {
-				struct cache_entry *ce = active_cache[pos];
-
-				if (!S_ISSPARSEDIR(ce->ce_mode))
-					continue;
-
-				/*
-				 * If the pre-wildcard length is longer than the sparse
-				 * directory name and the sparse directory is the first
-				 * component of the pathspec, need to expand the index.
-				 */
-				if (item.nowildcard_len > ce_namelen(ce) &&
-				    !strncmp(item.original, ce->name, ce_namelen(ce))) {
-					res = 1;
-					break;
-				}
-
-				/*
-				 * If the pre-wildcard length is shorter than the sparse
-				 * directory and the pathspec does not match the whole
-				 * directory, need to expand the index.
-				 */
-				if (!strncmp(item.original, ce->name, item.nowildcard_len) &&
-				    wildmatch(item.original, ce->name, 0)) {
-					res = 1;
-					break;
-				}
-			}
-		} else if (!path_in_cone_mode_sparse_checkout(item.original, &the_index) &&
-			   !matches_skip_worktree(pathspec, i, &skip_worktree_seen))
-			res = 1;
-
-		if (res > 0)
-			break;
-	}
-
-	free(skip_worktree_seen);
-	return res;
-}
-
 static int read_from_tree(const struct pathspec *pathspec,
 			  struct object_id *tree_oid,
 			  int intent_to_add)
@@ -273,7 +191,7 @@
 	opt.change = diff_change;
 	opt.add_remove = diff_addremove;
 
-	if (pathspec->nr && the_index.sparse_index && pathspec_needs_expanded_index(pathspec))
+	if (pathspec->nr && pathspec_needs_expanded_index(&the_index, pathspec))
 		ensure_full_index(&the_index);
 
 	if (do_diff_cache(tree_oid, &opt))
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 30fd8e8..fba6f5d 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -46,6 +46,7 @@
 "    --parents\n"
 "    --children\n"
 "    --objects | --objects-edge\n"
+"    --disk-usage[=human]\n"
 "    --unpacked\n"
 "    --header | --pretty\n"
 "    --[no-]object-names\n"
@@ -81,6 +82,7 @@
 
 static int show_disk_usage;
 static off_t total_disk_usage;
+static int human_readable;
 
 static off_t get_object_disk_usage(struct object *obj)
 {
@@ -368,6 +370,17 @@
 	return 1;
 }
 
+static void print_disk_usage(off_t size)
+{
+	struct strbuf sb = STRBUF_INIT;
+	if (human_readable)
+		strbuf_humanise_bytes(&sb, size);
+	else
+		strbuf_addf(&sb, "%"PRIuMAX, (uintmax_t)size);
+	puts(sb.buf);
+	strbuf_release(&sb);
+}
+
 static inline int parse_missing_action_value(const char *value)
 {
 	if (!strcmp(value, "error")) {
@@ -473,6 +486,7 @@
 				 int filter_provided_objects)
 {
 	struct bitmap_index *bitmap_git;
+	off_t size_from_bitmap;
 
 	if (!show_disk_usage)
 		return -1;
@@ -481,8 +495,8 @@
 	if (!bitmap_git)
 		return -1;
 
-	printf("%"PRIuMAX"\n",
-	       (uintmax_t)get_disk_usage_from_bitmap(bitmap_git, revs));
+	size_from_bitmap = get_disk_usage_from_bitmap(bitmap_git, revs);
+	print_disk_usage(size_from_bitmap);
 	return 0;
 }
 
@@ -624,7 +638,21 @@
 			continue;
 		}
 
-		if (!strcmp(arg, "--disk-usage")) {
+		if (skip_prefix(arg, "--disk-usage", &arg)) {
+			if (*arg == '=') {
+				if (!strcmp(++arg, "human")) {
+					human_readable = 1;
+				} else
+					die(_("invalid value for '%s': '%s', the only allowed format is '%s'"),
+					    "--disk-usage=<format>", arg, "human");
+			} else if (*arg) {
+				/*
+				 * Arguably should goto a label to continue chain of ifs?
+				 * Doesn't matter unless we try to add --disk-usage-foo
+				 * afterwards.
+				 */
+				usage(rev_list_usage);
+			}
 			show_disk_usage = 1;
 			info.flags |= REV_LIST_QUIET;
 			continue;
@@ -753,7 +781,7 @@
 	}
 
 	if (show_disk_usage)
-		printf("%"PRIuMAX"\n", (uintmax_t)total_disk_usage);
+		print_disk_usage(total_disk_usage);
 
 cleanup:
 	release_revisions(&revs);
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index b259d89..8f61050 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -195,7 +195,8 @@
 	return 0;
 }
 
-static int show_reference(const char *refname, const struct object_id *oid, int flag, void *cb_data)
+static int show_reference(const char *refname, const struct object_id *oid,
+			  int flag UNUSED, void *cb_data UNUSED)
 {
 	if (ref_excluded(ref_excludes, refname))
 		return 0;
@@ -203,7 +204,8 @@
 	return 0;
 }
 
-static int anti_reference(const char *refname, const struct object_id *oid, int flag, void *cb_data)
+static int anti_reference(const char *refname, const struct object_id *oid,
+			  int flag UNUSED, void *cb_data UNUSED)
 {
 	show_rev(REVERSED, oid, refname);
 	return 0;
@@ -479,6 +481,9 @@
 		if (!s)
 			s = help;
 
+		if (s == sb.buf)
+			die(_("missing opt-spec before option flags"));
+
 		if (s - sb.buf == 1) /* short option only */
 			o->short_name = *sb.buf;
 		else if (sb.buf[1] != ',') /* long option only */
diff --git a/builtin/revert.c b/builtin/revert.c
index f84c253..ee2a080 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -141,7 +141,7 @@
 
 	argc = parse_options(argc, argv, NULL, options, usage_str,
 			PARSE_OPT_KEEP_ARGV0 |
-			PARSE_OPT_KEEP_UNKNOWN);
+			PARSE_OPT_KEEP_UNKNOWN_OPT);
 
 	prepare_repo_settings(the_repository);
 	the_repository->settings.command_requires_full_index = 0;
@@ -246,6 +246,9 @@
 	res = run_sequencer(argc, argv, &opts);
 	if (res < 0)
 		die(_("revert failed"));
+	if (opts.revs)
+		release_revisions(opts.revs);
+	free(opts.revs);
 	return res;
 }
 
diff --git a/builtin/rm.c b/builtin/rm.c
index 84a935a..b6ba859 100644
--- a/builtin/rm.c
+++ b/builtin/rm.c
@@ -287,6 +287,8 @@
 	if (!index_only)
 		setup_work_tree();
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
 	hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
 
 	if (read_cache() < 0)
@@ -296,8 +298,9 @@
 
 	seen = xcalloc(pathspec.nr, 1);
 
-	/* TODO: audit for interaction with sparse-index. */
-	ensure_full_index(&the_index);
+	if (pathspec_needs_expanded_index(&the_index, &pathspec))
+		ensure_full_index(&the_index);
+
 	for (i = 0; i < active_nr; i++) {
 		const struct cache_entry *ce = active_cache[i];
 
diff --git a/builtin/shortlog.c b/builtin/shortlog.c
index 086dfee..7a1e1fe 100644
--- a/builtin/shortlog.c
+++ b/builtin/shortlog.c
@@ -381,6 +381,7 @@
 			break;
 		case PARSE_OPT_HELP:
 		case PARSE_OPT_ERROR:
+		case PARSE_OPT_SUBCOMMAND:
 			exit(129);
 		case PARSE_OPT_COMPLETE:
 			exit(0);
diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index 64c649c..d3f5715 100644
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -404,7 +404,7 @@
 }
 
 static int append_head_ref(const char *refname, const struct object_id *oid,
-			   int flag, void *cb_data)
+			   int flag UNUSED, void *cb_data UNUSED)
 {
 	struct object_id tmp;
 	int ofs = 11;
@@ -419,7 +419,7 @@
 }
 
 static int append_remote_ref(const char *refname, const struct object_id *oid,
-			     int flag, void *cb_data)
+			     int flag UNUSED, void *cb_data UNUSED)
 {
 	struct object_id tmp;
 	int ofs = 13;
@@ -434,7 +434,7 @@
 }
 
 static int append_tag_ref(const char *refname, const struct object_id *oid,
-			  int flag, void *cb_data)
+			  int flag UNUSED, void *cb_data UNUSED)
 {
 	if (!starts_with(refname, "refs/tags/"))
 		return 0;
diff --git a/builtin/show-ref.c b/builtin/show-ref.c
index 5fa207a..4856906 100644
--- a/builtin/show-ref.c
+++ b/builtin/show-ref.c
@@ -47,7 +47,7 @@
 }
 
 static int show_ref(const char *refname, const struct object_id *oid,
-		    int flag, void *cbdata)
+		    int flag UNUSED, void *cbdata UNUSED)
 {
 	if (show_head && !strcmp(refname, "HEAD"))
 		goto match;
@@ -77,8 +77,9 @@
 	return 0;
 }
 
-static int add_existing(const char *refname, const struct object_id *oid,
-			int flag, void *cbdata)
+static int add_existing(const char *refname,
+			const struct object_id *oid UNUSED,
+			int flag UNUSED, void *cbdata)
 {
 	struct string_list *list = (struct string_list *)cbdata;
 	string_list_insert(list, refname);
diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index f91e29b..287716d 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -48,7 +48,7 @@
 	NULL
 };
 
-static int sparse_checkout_list(int argc, const char **argv)
+static int sparse_checkout_list(int argc, const char **argv, const char *prefix)
 {
 	static struct option builtin_sparse_checkout_list_options[] = {
 		OPT_END(),
@@ -60,7 +60,7 @@
 	if (!core_apply_sparse_checkout)
 		die(_("this worktree is not sparse"));
 
-	argc = parse_options(argc, argv, NULL,
+	argc = parse_options(argc, argv, prefix,
 			     builtin_sparse_checkout_list_options,
 			     builtin_sparse_checkout_list_usage, 0);
 
@@ -431,7 +431,7 @@
 	int sparse_index;
 } init_opts;
 
-static int sparse_checkout_init(int argc, const char **argv)
+static int sparse_checkout_init(int argc, const char **argv, const char *prefix)
 {
 	struct pattern_list pl;
 	char *sparse_filename;
@@ -452,7 +452,7 @@
 	init_opts.cone_mode = -1;
 	init_opts.sparse_index = -1;
 
-	argc = parse_options(argc, argv, NULL,
+	argc = parse_options(argc, argv, prefix,
 			     builtin_sparse_checkout_init_options,
 			     builtin_sparse_checkout_init_usage, 0);
 
@@ -767,7 +767,7 @@
 	argc = parse_options(argc, argv, prefix,
 			     builtin_sparse_checkout_add_options,
 			     builtin_sparse_checkout_add_usage,
-			     PARSE_OPT_KEEP_UNKNOWN);
+			     PARSE_OPT_KEEP_UNKNOWN_OPT);
 
 	sanitize_paths(argc, argv, prefix, add_opts.skip_checks);
 
@@ -813,7 +813,7 @@
 	argc = parse_options(argc, argv, prefix,
 			     builtin_sparse_checkout_set_options,
 			     builtin_sparse_checkout_set_usage,
-			     PARSE_OPT_KEEP_UNKNOWN);
+			     PARSE_OPT_KEEP_UNKNOWN_OPT);
 
 	if (update_modes(&set_opts.cone_mode, &set_opts.sparse_index))
 		return 1;
@@ -843,7 +843,8 @@
 	int sparse_index;
 } reapply_opts;
 
-static int sparse_checkout_reapply(int argc, const char **argv)
+static int sparse_checkout_reapply(int argc, const char **argv,
+				   const char *prefix)
 {
 	static struct option builtin_sparse_checkout_reapply_options[] = {
 		OPT_BOOL(0, "cone", &reapply_opts.cone_mode,
@@ -859,7 +860,7 @@
 	reapply_opts.cone_mode = -1;
 	reapply_opts.sparse_index = -1;
 
-	argc = parse_options(argc, argv, NULL,
+	argc = parse_options(argc, argv, prefix,
 			     builtin_sparse_checkout_reapply_options,
 			     builtin_sparse_checkout_reapply_usage, 0);
 
@@ -876,7 +877,8 @@
 	NULL
 };
 
-static int sparse_checkout_disable(int argc, const char **argv)
+static int sparse_checkout_disable(int argc, const char **argv,
+				   const char *prefix)
 {
 	static struct option builtin_sparse_checkout_disable_options[] = {
 		OPT_END(),
@@ -895,7 +897,7 @@
 	 * forcibly return to a dense checkout regardless of initial state.
 	 */
 
-	argc = parse_options(argc, argv, NULL,
+	argc = parse_options(argc, argv, prefix,
 			     builtin_sparse_checkout_disable_options,
 			     builtin_sparse_checkout_disable_usage, 0);
 
@@ -922,39 +924,25 @@
 
 int cmd_sparse_checkout(int argc, const char **argv, const char *prefix)
 {
-	static struct option builtin_sparse_checkout_options[] = {
+	parse_opt_subcommand_fn *fn = NULL;
+	struct option builtin_sparse_checkout_options[] = {
+		OPT_SUBCOMMAND("list", &fn, sparse_checkout_list),
+		OPT_SUBCOMMAND("init", &fn, sparse_checkout_init),
+		OPT_SUBCOMMAND("set", &fn, sparse_checkout_set),
+		OPT_SUBCOMMAND("add", &fn, sparse_checkout_add),
+		OPT_SUBCOMMAND("reapply", &fn, sparse_checkout_reapply),
+		OPT_SUBCOMMAND("disable", &fn, sparse_checkout_disable),
 		OPT_END(),
 	};
 
-	if (argc == 2 && !strcmp(argv[1], "-h"))
-		usage_with_options(builtin_sparse_checkout_usage,
-				   builtin_sparse_checkout_options);
-
 	argc = parse_options(argc, argv, prefix,
 			     builtin_sparse_checkout_options,
-			     builtin_sparse_checkout_usage,
-			     PARSE_OPT_STOP_AT_NON_OPTION);
+			     builtin_sparse_checkout_usage, 0);
 
 	git_config(git_default_config, NULL);
 
 	prepare_repo_settings(the_repository);
 	the_repository->settings.command_requires_full_index = 0;
 
-	if (argc > 0) {
-		if (!strcmp(argv[0], "list"))
-			return sparse_checkout_list(argc, argv);
-		if (!strcmp(argv[0], "init"))
-			return sparse_checkout_init(argc, argv);
-		if (!strcmp(argv[0], "set"))
-			return sparse_checkout_set(argc, argv, prefix);
-		if (!strcmp(argv[0], "add"))
-			return sparse_checkout_add(argc, argv, prefix);
-		if (!strcmp(argv[0], "reapply"))
-			return sparse_checkout_reapply(argc, argv);
-		if (!strcmp(argv[0], "disable"))
-			return sparse_checkout_disable(argc, argv);
-	}
-
-	usage_with_options(builtin_sparse_checkout_usage,
-			   builtin_sparse_checkout_options);
+	return fn(argc, argv, prefix);
 }
diff --git a/builtin/stash.c b/builtin/stash.c
index 30fa101..2274aae 100644
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -638,9 +638,12 @@
 	return ret;
 }
 
-static int reject_reflog_ent(struct object_id *ooid, struct object_id *noid,
-			     const char *email, timestamp_t timestamp, int tz,
-			     const char *message, void *cb_data)
+static int reject_reflog_ent(struct object_id *ooid UNUSED,
+			     struct object_id *noid UNUSED,
+			     const char *email UNUSED,
+			     timestamp_t timestamp UNUSED,
+			     int tz UNUSED, const char *message UNUSED,
+			     void *cb_data UNUSED)
 {
 	return 1;
 }
@@ -782,7 +785,7 @@
 
 	argc = parse_options(argc, argv, prefix, options,
 			     git_stash_list_usage,
-			     PARSE_OPT_KEEP_UNKNOWN);
+			     PARSE_OPT_KEEP_UNKNOWN_OPT);
 
 	if (!ref_exists(ref_stash))
 		return 0;
@@ -873,7 +876,7 @@
 	init_revisions(&rev, prefix);
 
 	argc = parse_options(argc, argv, prefix, options, git_stash_show_usage,
-			     PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN |
+			     PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN_OPT |
 			     PARSE_OPT_KEEP_DASHDASH);
 
 	strvec_push(&revision_args, argv[0]);
@@ -979,7 +982,7 @@
 
 	argc = parse_options(argc, argv, prefix, options,
 			     git_stash_store_usage,
-			     PARSE_OPT_KEEP_UNKNOWN);
+			     PARSE_OPT_KEEP_UNKNOWN_OPT);
 
 	if (argc != 1) {
 		if (!quiet)
@@ -1739,6 +1742,11 @@
 			     include_untracked, only_staged);
 }
 
+static int push_stash_unassumed(int argc, const char **argv, const char *prefix)
+{
+	return push_stash(argc, argv, prefix, 0);
+}
+
 static int save_stash(int argc, const char **argv, const char *prefix)
 {
 	int keep_index = -1;
@@ -1787,15 +1795,28 @@
 	pid_t pid = getpid();
 	const char *index_file;
 	struct strvec args = STRVEC_INIT;
-
+	parse_opt_subcommand_fn *fn = NULL;
 	struct option options[] = {
+		OPT_SUBCOMMAND("apply", &fn, apply_stash),
+		OPT_SUBCOMMAND("clear", &fn, clear_stash),
+		OPT_SUBCOMMAND("drop", &fn, drop_stash),
+		OPT_SUBCOMMAND("pop", &fn, pop_stash),
+		OPT_SUBCOMMAND("branch", &fn, branch_stash),
+		OPT_SUBCOMMAND("list", &fn, list_stash),
+		OPT_SUBCOMMAND("show", &fn, show_stash),
+		OPT_SUBCOMMAND("store", &fn, store_stash),
+		OPT_SUBCOMMAND("create", &fn, create_stash),
+		OPT_SUBCOMMAND("push", &fn, push_stash_unassumed),
+		OPT_SUBCOMMAND_F("save", &fn, save_stash, PARSE_OPT_NOCOMPLETE),
 		OPT_END()
 	};
 
 	git_config(git_stash_config, NULL);
 
 	argc = parse_options(argc, argv, prefix, options, git_stash_usage,
-			     PARSE_OPT_KEEP_UNKNOWN | PARSE_OPT_KEEP_DASHDASH);
+			     PARSE_OPT_SUBCOMMAND_OPTIONAL |
+			     PARSE_OPT_KEEP_UNKNOWN_OPT |
+			     PARSE_OPT_KEEP_DASHDASH);
 
 	prepare_repo_settings(the_repository);
 	the_repository->settings.command_requires_full_index = 0;
@@ -1804,33 +1825,10 @@
 	strbuf_addf(&stash_index_path, "%s.stash.%" PRIuMAX, index_file,
 		    (uintmax_t)pid);
 
-	if (!argc)
-		return !!push_stash(0, NULL, prefix, 0);
-	else if (!strcmp(argv[0], "apply"))
-		return !!apply_stash(argc, argv, prefix);
-	else if (!strcmp(argv[0], "clear"))
-		return !!clear_stash(argc, argv, prefix);
-	else if (!strcmp(argv[0], "drop"))
-		return !!drop_stash(argc, argv, prefix);
-	else if (!strcmp(argv[0], "pop"))
-		return !!pop_stash(argc, argv, prefix);
-	else if (!strcmp(argv[0], "branch"))
-		return !!branch_stash(argc, argv, prefix);
-	else if (!strcmp(argv[0], "list"))
-		return !!list_stash(argc, argv, prefix);
-	else if (!strcmp(argv[0], "show"))
-		return !!show_stash(argc, argv, prefix);
-	else if (!strcmp(argv[0], "store"))
-		return !!store_stash(argc, argv, prefix);
-	else if (!strcmp(argv[0], "create"))
-		return !!create_stash(argc, argv, prefix);
-	else if (!strcmp(argv[0], "push"))
-		return !!push_stash(argc, argv, prefix, 0);
-	else if (!strcmp(argv[0], "save"))
-		return !!save_stash(argc, argv, prefix);
-	else if (*argv[0] != '-')
-		usage_msg_optf(_("unknown subcommand: %s"),
-			       git_stash_usage, options, argv[0]);
+	if (fn)
+		return !!fn(argc, argv, prefix);
+	else if (!argc)
+		return !!push_stash_unassumed(0, NULL, prefix);
 
 	/* Assume 'stash push' */
 	strvec_push(&args, "push");
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index c597df7..ad834f9 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -31,45 +31,61 @@
 typedef void (*each_submodule_fn)(const struct cache_entry *list_item,
 				  void *cb_data);
 
-static char *repo_get_default_remote(struct repository *repo)
+static int repo_get_default_remote(struct repository *repo, char **default_remote)
 {
-	char *dest = NULL, *ret;
+	char *dest = NULL;
 	struct strbuf sb = STRBUF_INIT;
 	struct ref_store *store = get_main_ref_store(repo);
 	const char *refname = refs_resolve_ref_unsafe(store, "HEAD", 0, NULL,
 						      NULL);
 
 	if (!refname)
-		die(_("No such ref: %s"), "HEAD");
+		return die_message(_("No such ref: %s"), "HEAD");
 
 	/* detached HEAD */
-	if (!strcmp(refname, "HEAD"))
-		return xstrdup("origin");
+	if (!strcmp(refname, "HEAD")) {
+		*default_remote = xstrdup("origin");
+		return 0;
+	}
 
 	if (!skip_prefix(refname, "refs/heads/", &refname))
-		die(_("Expecting a full ref name, got %s"), refname);
+		return die_message(_("Expecting a full ref name, got %s"),
+				   refname);
 
 	strbuf_addf(&sb, "branch.%s.remote", refname);
 	if (repo_config_get_string(repo, sb.buf, &dest))
-		ret = xstrdup("origin");
+		*default_remote = xstrdup("origin");
 	else
-		ret = dest;
+		*default_remote = dest;
 
 	strbuf_release(&sb);
-	return ret;
+	return 0;
 }
 
-static char *get_default_remote_submodule(const char *module_path)
+static int get_default_remote_submodule(const char *module_path, char **default_remote)
 {
 	struct repository subrepo;
+	int ret;
 
-	repo_submodule_init(&subrepo, the_repository, module_path, null_oid());
-	return repo_get_default_remote(&subrepo);
+	if (repo_submodule_init(&subrepo, the_repository, module_path,
+				null_oid()) < 0)
+		return die_message(_("could not get a repository handle for submodule '%s'"),
+				   module_path);
+	ret = repo_get_default_remote(&subrepo, default_remote);
+	repo_clear(&subrepo);
+
+	return ret;
 }
 
 static char *get_default_remote(void)
 {
-	return repo_get_default_remote(the_repository);
+	char *default_remote;
+	int code = repo_get_default_remote(the_repository, &default_remote);
+
+	if (code)
+		exit(code);
+
+	return default_remote;
 }
 
 static char *resolve_relative_url(const char *rel_url, const char *up_path, int quiet)
@@ -96,32 +112,11 @@
 	return resolved_url;
 }
 
-static int resolve_relative_url_test(int argc, const char **argv, const char *prefix)
+/* the result should be freed by the caller. */
+static char *get_submodule_displaypath(const char *path, const char *prefix)
 {
-	char *remoteurl, *res;
-	const char *up_path, *url;
+	const char *super_prefix = get_super_prefix();
 
-	if (argc != 4)
-		die("resolve-relative-url-test only accepts three arguments: <up_path> <remoteurl> <url>");
-
-	up_path = argv[1];
-	remoteurl = xstrdup(argv[2]);
-	url = argv[3];
-
-	if (!strcmp(up_path, "(null)"))
-		up_path = NULL;
-
-	res = relative_url(remoteurl, url, up_path);
-	puts(res);
-	free(res);
-	free(remoteurl);
-	return 0;
-}
-
-static char *do_get_submodule_displaypath(const char *path,
-					  const char *prefix,
-					  const char *super_prefix)
-{
 	if (prefix && super_prefix) {
 		BUG("cannot have prefix '%s' and superprefix '%s'",
 		    prefix, super_prefix);
@@ -137,13 +132,6 @@
 	}
 }
 
-/* the result should be freed by the caller. */
-static char *get_submodule_displaypath(const char *path, const char *prefix)
-{
-	const char *super_prefix = get_super_prefix();
-	return do_get_submodule_displaypath(path, prefix, super_prefix);
-}
-
 static char *compute_rev_name(const char *sub_path, const char* object_id)
 {
 	struct strbuf sb = STRBUF_INIT;
@@ -188,6 +176,11 @@
 };
 #define MODULE_LIST_INIT { 0 }
 
+static void module_list_release(struct module_list *ml)
+{
+	free(ml->entries);
+}
+
 static int module_list_compute(int argc, const char **argv,
 			       const char *prefix,
 			       struct pathspec *pathspec,
@@ -195,6 +188,7 @@
 {
 	int i, result = 0;
 	char *ps_matched = NULL;
+
 	parse_pathspec(pathspec, 0,
 		       PATHSPEC_PREFER_FULL,
 		       prefix, argv);
@@ -249,7 +243,7 @@
 		active_modules.entries[active_modules.nr++] = ce;
 	}
 
-	free(list->entries);
+	module_list_release(list);
 	*list = active_modules;
 }
 
@@ -272,49 +266,11 @@
 	return strbuf_detach(&sb, NULL);
 }
 
-static int module_list(int argc, const char **argv, const char *prefix)
-{
-	int i;
-	struct pathspec pathspec;
-	struct module_list list = MODULE_LIST_INIT;
-
-	struct option module_list_options[] = {
-		OPT_STRING(0, "prefix", &prefix,
-			   N_("path"),
-			   N_("alternative anchor for relative paths")),
-		OPT_END()
-	};
-
-	const char *const git_submodule_helper_usage[] = {
-		N_("git submodule--helper list [--prefix=<path>] [<path>...]"),
-		NULL
-	};
-
-	argc = parse_options(argc, argv, prefix, module_list_options,
-			     git_submodule_helper_usage, 0);
-
-	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
-		return 1;
-
-	for (i = 0; i < list.nr; i++) {
-		const struct cache_entry *ce = list.entries[i];
-
-		if (ce_stage(ce))
-			printf("%06o %s U\t", ce->ce_mode,
-			       oid_to_hex(null_oid()));
-		else
-			printf("%06o %s %d\t", ce->ce_mode,
-			       oid_to_hex(&ce->oid), ce_stage(ce));
-
-		fprintf(stdout, "%s\n", ce->name);
-	}
-	return 0;
-}
-
 static void for_each_listed_submodule(const struct module_list *list,
 				      each_submodule_fn fn, void *cb_data)
 {
 	int i;
+
 	for (i = 0; i < list->nr; i++)
 		fn(list->entries[i], cb_data);
 }
@@ -334,7 +290,6 @@
 	struct foreach_cb *info = cb_data;
 	const char *path = list_item->name;
 	const struct object_id *ce_oid = &list_item->oid;
-
 	const struct submodule *sub;
 	struct child_process cp = CHILD_PROCESS_INIT;
 	char *displaypath;
@@ -433,26 +388,25 @@
 static int module_foreach(int argc, const char **argv, const char *prefix)
 {
 	struct foreach_cb info = FOREACH_CB_INIT;
-	struct pathspec pathspec;
+	struct pathspec pathspec = { 0 };
 	struct module_list list = MODULE_LIST_INIT;
-
 	struct option module_foreach_options[] = {
 		OPT__QUIET(&info.quiet, N_("suppress output of entering each submodule command")),
 		OPT_BOOL(0, "recursive", &info.recursive,
 			 N_("recurse into nested submodules")),
 		OPT_END()
 	};
-
 	const char *const git_submodule_helper_usage[] = {
-		N_("git submodule--helper foreach [--quiet] [--recursive] [--] <command>"),
+		N_("git submodule foreach [--quiet] [--recursive] [--] <command>"),
 		NULL
 	};
+	int ret = 1;
 
 	argc = parse_options(argc, argv, prefix, module_foreach_options,
 			     git_submodule_helper_usage, 0);
 
 	if (module_list_compute(0, NULL, prefix, &pathspec, &list) < 0)
-		return 1;
+		goto cleanup;
 
 	info.argc = argc;
 	info.argv = argv;
@@ -460,7 +414,11 @@
 
 	for_each_listed_submodule(&list, runcommand_in_submodule_cb, &info);
 
-	return 0;
+	ret = 0;
+cleanup:
+	module_list_release(&list);
+	clear_pathspec(&pathspec);
+	return ret;
 }
 
 static int starts_with_dot_slash(const char *const path)
@@ -477,22 +435,19 @@
 
 struct init_cb {
 	const char *prefix;
-	const char *superprefix;
 	unsigned int flags;
 };
 #define INIT_CB_INIT { 0 }
 
 static void init_submodule(const char *path, const char *prefix,
-			   const char *superprefix, unsigned int flags)
+			   unsigned int flags)
 {
 	const struct submodule *sub;
 	struct strbuf sb = STRBUF_INIT;
-	char *upd = NULL, *url = NULL, *displaypath;
+	const char *upd;
+	char *url = NULL, *displaypath;
 
-	/* try superprefix from the environment, if it is not passed explicitly */
-	if (!superprefix)
-		superprefix = get_super_prefix();
-	displaypath = do_get_submodule_displaypath(path, prefix, superprefix);
+	displaypath = get_submodule_displaypath(path, prefix);
 
 	sub = submodule_from_path(the_repository, null_oid(), path);
 
@@ -529,6 +484,7 @@
 		if (starts_with_dot_dot_slash(url) ||
 		    starts_with_dot_slash(url)) {
 			char *oldurl = url;
+
 			url = resolve_relative_url(oldurl, NULL, 0);
 			free(oldurl);
 		}
@@ -545,14 +501,15 @@
 
 	/* Copy "update" setting when it is not set yet */
 	strbuf_addf(&sb, "submodule.%s.update", sub->name);
-	if (git_config_get_string(sb.buf, &upd) &&
+	if (git_config_get_string_tmp(sb.buf, &upd) &&
 	    sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
 		if (sub->update_strategy.type == SM_UPDATE_COMMAND) {
 			fprintf(stderr, _("warning: command update mode suggested for submodule '%s'\n"),
 				sub->name);
-			upd = xstrdup("none");
-		} else
-			upd = xstrdup(submodule_strategy_to_string(&sub->update_strategy));
+			upd = "none";
+		} else {
+			upd = submodule_update_type_to_string(sub->update_strategy.type);
+		}
 
 		if (git_config_set_gently(sb.buf, upd))
 			die(_("Failed to register update mode for submodule path '%s'"), displaypath);
@@ -560,37 +517,36 @@
 	strbuf_release(&sb);
 	free(displaypath);
 	free(url);
-	free(upd);
 }
 
 static void init_submodule_cb(const struct cache_entry *list_item, void *cb_data)
 {
 	struct init_cb *info = cb_data;
-	init_submodule(list_item->name, info->prefix, info->superprefix, info->flags);
+
+	init_submodule(list_item->name, info->prefix, info->flags);
 }
 
 static int module_init(int argc, const char **argv, const char *prefix)
 {
 	struct init_cb info = INIT_CB_INIT;
-	struct pathspec pathspec;
+	struct pathspec pathspec = { 0 };
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
-
 	struct option module_init_options[] = {
 		OPT__QUIET(&quiet, N_("suppress output for initializing a submodule")),
 		OPT_END()
 	};
-
 	const char *const git_submodule_helper_usage[] = {
-		N_("git submodule--helper init [<options>] [<path>]"),
+		N_("git submodule init [<options>] [<path>]"),
 		NULL
 	};
+	int ret = 1;
 
 	argc = parse_options(argc, argv, prefix, module_init_options,
 			     git_submodule_helper_usage, 0);
 
 	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
-		return 1;
+		goto cleanup;
 
 	/*
 	 * If there are no path args and submodule.active is set then,
@@ -605,7 +561,11 @@
 
 	for_each_listed_submodule(&list, init_submodule_cb, &info);
 
-	return 0;
+	ret = 0;
+cleanup:
+	module_list_release(&list);
+	clear_pathspec(&pathspec);
+	return ret;
 }
 
 struct status_cb {
@@ -623,20 +583,23 @@
 	printf("%c%s %s", state, oid_to_hex(oid), displaypath);
 
 	if (state == ' ' || state == '+') {
-		const char *name = compute_rev_name(path, oid_to_hex(oid));
+		char *name = compute_rev_name(path, oid_to_hex(oid));
 
 		if (name)
 			printf(" (%s)", name);
+		free(name);
 	}
 
 	printf("\n");
 }
 
-static int handle_submodule_head_ref(const char *refname,
-				     const struct object_id *oid, int flags,
+static int handle_submodule_head_ref(const char *refname UNUSED,
+				     const struct object_id *oid,
+				     int flags UNUSED,
 				     void *cb_data)
 {
 	struct object_id *output = cb_data;
+
 	if (oid)
 		oidcpy(output, oid);
 
@@ -743,6 +706,7 @@
 				void *cb_data)
 {
 	struct status_cb *info = cb_data;
+
 	status_submodule(list_item->name, &list_item->oid, list_item->ce_flags,
 			 info->prefix, info->flags);
 }
@@ -750,27 +714,26 @@
 static int module_status(int argc, const char **argv, const char *prefix)
 {
 	struct status_cb info = STATUS_CB_INIT;
-	struct pathspec pathspec;
+	struct pathspec pathspec = { 0 };
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
-
 	struct option module_status_options[] = {
 		OPT__QUIET(&quiet, N_("suppress submodule status output")),
 		OPT_BIT(0, "cached", &info.flags, N_("use commit stored in the index instead of the one stored in the submodule HEAD"), OPT_CACHED),
 		OPT_BIT(0, "recursive", &info.flags, N_("recurse into nested submodules"), OPT_RECURSIVE),
 		OPT_END()
 	};
-
 	const char *const git_submodule_helper_usage[] = {
 		N_("git submodule status [--quiet] [--cached] [--recursive] [<path>...]"),
 		NULL
 	};
+	int ret = 1;
 
 	argc = parse_options(argc, argv, prefix, module_status_options,
 			     git_submodule_helper_usage, 0);
 
 	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
-		return 1;
+		goto cleanup;
 
 	info.prefix = prefix;
 	if (quiet)
@@ -778,25 +741,11 @@
 
 	for_each_listed_submodule(&list, status_submodule_cb, &info);
 
-	return 0;
-}
-
-static int module_name(int argc, const char **argv, const char *prefix)
-{
-	const struct submodule *sub;
-
-	if (argc != 2)
-		usage(_("git submodule--helper name <path>"));
-
-	sub = submodule_from_path(the_repository, null_oid(), argv[1]);
-
-	if (!sub)
-		die(_("no submodule mapping found in .gitmodules for path '%s'"),
-		    argv[1]);
-
-	printf("%s\n", sub->name);
-
-	return 0;
+	ret = 0;
+cleanup:
+	module_list_release(&list);
+	clear_pathspec(&pathspec);
+	return ret;
 }
 
 struct module_cb {
@@ -805,16 +754,34 @@
 	struct object_id oid_src;
 	struct object_id oid_dst;
 	char status;
-	const char *sm_path;
+	char *sm_path;
 };
 #define MODULE_CB_INIT { 0 }
 
+static void module_cb_release(struct module_cb *mcb)
+{
+	free(mcb->sm_path);
+}
+
 struct module_cb_list {
 	struct module_cb **entries;
 	int alloc, nr;
 };
 #define MODULE_CB_LIST_INIT { 0 }
 
+static void module_cb_list_release(struct module_cb_list *mcbl)
+{
+	int i;
+
+	for (i = 0; i < mcbl->nr; i++) {
+		struct module_cb *mcb = mcbl->entries[i];
+
+		module_cb_release(mcb);
+		free(mcb);
+	}
+	free(mcbl->entries);
+}
+
 struct summary_cb {
 	int argc;
 	const char **argv;
@@ -851,7 +818,7 @@
 	return strbuf_detach(&result, NULL);
 }
 
-static void print_submodule_summary(struct summary_cb *info, char *errmsg,
+static void print_submodule_summary(struct summary_cb *info, const char *errmsg,
 				    int total_commits, const char *displaypath,
 				    const char *src_abbrev, const char *dst_abbrev,
 				    struct module_cb *p)
@@ -909,12 +876,13 @@
 {
 	char *displaypath, *src_abbrev = NULL, *dst_abbrev;
 	int missing_src = 0, missing_dst = 0;
-	char *errmsg = NULL;
+	struct strbuf errmsg = STRBUF_INIT;
 	int total_commits = -1;
 
 	if (!info->cached && oideq(&p->oid_dst, null_oid())) {
 		if (S_ISGITLINK(p->mod_dst)) {
 			struct ref_store *refs = get_submodule_ref_store(p->sm_path);
+
 			if (refs)
 				refs_head_ref(refs, handle_submodule_head_ref, &p->oid_dst);
 		} else if (S_ISLNK(p->mod_dst) || S_ISREG(p->mod_dst)) {
@@ -1009,28 +977,27 @@
 		 * submodule, i.e., deleted or changed to blob
 		 */
 		if (S_ISGITLINK(p->mod_dst)) {
-			struct strbuf errmsg_str = STRBUF_INIT;
 			if (missing_src && missing_dst) {
-				strbuf_addf(&errmsg_str, "  Warn: %s doesn't contain commits %s and %s\n",
+				strbuf_addf(&errmsg, "  Warn: %s doesn't contain commits %s and %s\n",
 					    displaypath, oid_to_hex(&p->oid_src),
 					    oid_to_hex(&p->oid_dst));
 			} else {
-				strbuf_addf(&errmsg_str, "  Warn: %s doesn't contain commit %s\n",
+				strbuf_addf(&errmsg, "  Warn: %s doesn't contain commit %s\n",
 					    displaypath, missing_src ?
 					    oid_to_hex(&p->oid_src) :
 					    oid_to_hex(&p->oid_dst));
 			}
-			errmsg = strbuf_detach(&errmsg_str, NULL);
 		}
 	}
 
-	print_submodule_summary(info, errmsg, total_commits,
-				displaypath, src_abbrev,
+	print_submodule_summary(info, errmsg.len ? errmsg.buf : NULL,
+				total_commits, displaypath, src_abbrev,
 				dst_abbrev, p);
 
 	free(displaypath);
 	free(src_abbrev);
 	free(dst_abbrev);
+	strbuf_release(&errmsg);
 }
 
 static void prepare_submodule_summary(struct summary_cb *info,
@@ -1114,6 +1081,9 @@
 {
 	struct strvec diff_args = STRVEC_INIT;
 	struct rev_info rev;
+	struct setup_revision_opt opt = {
+		.free_removed_argv_elements = 1,
+	};
 	struct module_cb_list list = MODULE_CB_LIST_INIT;
 	int ret = 0;
 
@@ -1131,7 +1101,7 @@
 	init_revisions(&rev, info->prefix);
 	rev.abbrev = 0;
 	precompose_argv_prefix(diff_args.nr, diff_args.v, NULL);
-	setup_revisions(diff_args.nr, diff_args.v, &rev, NULL);
+	setup_revisions(diff_args.nr, diff_args.v, &rev, &opt);
 	rev.diffopt.output_format = DIFF_FORMAT_NO_OUTPUT | DIFF_FORMAT_CALLBACK;
 	rev.diffopt.format_callback = submodule_summary_callback;
 	rev.diffopt.format_callback_data = &list;
@@ -1158,6 +1128,7 @@
 cleanup:
 	strvec_clear(&diff_args);
 	release_revisions(&rev);
+	module_cb_list_release(&list);
 	return ret;
 }
 
@@ -1171,7 +1142,6 @@
 	enum diff_cmd diff_cmd = DIFF_INDEX;
 	struct object_id head_oid;
 	int ret;
-
 	struct option module_summary_options[] = {
 		OPT_BOOL(0, "cached", &cached,
 			 N_("use the commit stored in the index instead of the submodule HEAD")),
@@ -1183,9 +1153,8 @@
 			     N_("limit the summary size")),
 		OPT_END()
 	};
-
 	const char *const git_submodule_helper_usage[] = {
-		N_("git submodule--helper summary [<options>] [<commit>] [--] [<path>]"),
+		N_("git submodule summary [<options>] [<commit>] [--] [<path>]"),
 		NULL
 	};
 
@@ -1245,6 +1214,7 @@
 	char *sub_origin_url, *super_config_url, *displaypath, *default_remote;
 	struct strbuf sb = STRBUF_INIT;
 	char *sub_config_path = NULL;
+	int code;
 
 	if (!is_submodule_active(the_repository, path))
 		return;
@@ -1255,6 +1225,7 @@
 		if (starts_with_dot_dot_slash(sub->url) ||
 		    starts_with_dot_slash(sub->url)) {
 			char *up_path = get_up_path(path);
+
 			sub_origin_url = resolve_relative_url(sub->url, up_path, 1);
 			super_config_url = resolve_relative_url(sub->url, NULL, 1);
 			free(up_path);
@@ -1283,10 +1254,9 @@
 		goto cleanup;
 
 	strbuf_reset(&sb);
-	default_remote = get_default_remote_submodule(path);
-	if (!default_remote)
-		die(_("failed to get the default remote for submodule '%s'"),
-		      path);
+	code = get_default_remote_submodule(path, &default_remote);
+	if (code)
+		exit(code);
 
 	remote_key = xstrfmt("remote.%s.url", default_remote);
 	free(default_remote);
@@ -1330,34 +1300,34 @@
 static void sync_submodule_cb(const struct cache_entry *list_item, void *cb_data)
 {
 	struct sync_cb *info = cb_data;
+
 	sync_submodule(list_item->name, info->prefix, info->flags);
 }
 
 static int module_sync(int argc, const char **argv, const char *prefix)
 {
 	struct sync_cb info = SYNC_CB_INIT;
-	struct pathspec pathspec;
+	struct pathspec pathspec = { 0 };
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
 	int recursive = 0;
-
 	struct option module_sync_options[] = {
 		OPT__QUIET(&quiet, N_("suppress output of synchronizing submodule url")),
 		OPT_BOOL(0, "recursive", &recursive,
 			N_("recurse into nested submodules")),
 		OPT_END()
 	};
-
 	const char *const git_submodule_helper_usage[] = {
-		N_("git submodule--helper sync [--quiet] [--recursive] [<path>]"),
+		N_("git submodule sync [--quiet] [--recursive] [<path>]"),
 		NULL
 	};
+	int ret = 1;
 
 	argc = parse_options(argc, argv, prefix, module_sync_options,
 			     git_submodule_helper_usage, 0);
 
 	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
-		return 1;
+		goto cleanup;
 
 	info.prefix = prefix;
 	if (quiet)
@@ -1367,7 +1337,11 @@
 
 	for_each_listed_submodule(&list, sync_submodule_cb, &info);
 
-	return 0;
+	ret = 0;
+cleanup:
+	module_list_release(&list);
+	clear_pathspec(&pathspec);
+	return ret;
 }
 
 struct deinit_cb {
@@ -1411,6 +1385,7 @@
 
 		if (!(flags & OPT_FORCE)) {
 			struct child_process cp_rm = CHILD_PROCESS_INIT;
+
 			cp_rm.git_cmd = 1;
 			strvec_pushl(&cp_rm.args, "rm", "-qn",
 				     path, NULL);
@@ -1447,6 +1422,7 @@
 	/* remove the .git/config entries (unless the user already did it) */
 	if (!capture_command(&cp_config, &sb_config, 0) && sb_config.len) {
 		char *sub_key = xstrfmt("submodule.%s", sub->name);
+
 		/*
 		 * remove the whole section so we have a clean state when
 		 * the user later decides to init this submodule again
@@ -1474,23 +1450,22 @@
 static int module_deinit(int argc, const char **argv, const char *prefix)
 {
 	struct deinit_cb info = DEINIT_CB_INIT;
-	struct pathspec pathspec;
+	struct pathspec pathspec = { 0 };
 	struct module_list list = MODULE_LIST_INIT;
 	int quiet = 0;
 	int force = 0;
 	int all = 0;
-
 	struct option module_deinit_options[] = {
 		OPT__QUIET(&quiet, N_("suppress submodule status output")),
 		OPT__FORCE(&force, N_("remove submodule working trees even if they contain local changes"), 0),
 		OPT_BOOL(0, "all", &all, N_("unregister all submodules")),
 		OPT_END()
 	};
-
 	const char *const git_submodule_helper_usage[] = {
 		N_("git submodule deinit [--quiet] [-f | --force] [--all | [--] [<path>...]]"),
 		NULL
 	};
+	int ret = 1;
 
 	argc = parse_options(argc, argv, prefix, module_deinit_options,
 			     git_submodule_helper_usage, 0);
@@ -1505,7 +1480,7 @@
 		die(_("Use '--all' if you really want to deinitialize all submodules"));
 
 	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
-		return 1;
+		goto cleanup;
 
 	info.prefix = prefix;
 	if (quiet)
@@ -1515,7 +1490,11 @@
 
 	for_each_listed_submodule(&list, deinit_submodule_cb, &info);
 
-	return 0;
+	ret = 0;
+cleanup:
+	module_list_release(&list);
+	clear_pathspec(&pathspec);
+	return ret;
 }
 
 struct module_clone_data {
@@ -1525,7 +1504,6 @@
 	const char *url;
 	const char *depth;
 	struct list_objects_filter_options *filter_options;
-	struct string_list reference;
 	unsigned int quiet: 1;
 	unsigned int progress: 1;
 	unsigned int dissociate: 1;
@@ -1533,7 +1511,6 @@
 	int single_branch;
 };
 #define MODULE_CLONE_DATA_INIT { \
-	.reference = STRING_LIST_INIT_NODUP, \
 	.single_branch = -1, \
 }
 
@@ -1574,7 +1551,9 @@
 		struct strbuf err = STRBUF_INIT;
 		strbuf_add(&sb, odb->path, len);
 
-		repo_init(&alternate, sb.buf, NULL);
+		if (repo_init(&alternate, sb.buf, NULL) < 0)
+			die(_("could not get a repository handle for gitdir '%s'"),
+			    sb.buf);
 
 		/*
 		 * We need to end the new path with '/' to mark it as a dir,
@@ -1589,7 +1568,9 @@
 
 		sm_alternate = compute_alternate_path(sb.buf, &err);
 		if (sm_alternate) {
-			string_list_append(sas->reference, xstrdup(sb.buf));
+			char *p = strbuf_detach(&sb, NULL);
+
+			string_list_append(sas->reference, p)->util = p;
 			free(sm_alternate);
 		} else {
 			switch (sas->error_mode) {
@@ -1648,23 +1629,31 @@
 	free(error_strategy);
 }
 
-static int clone_submodule(struct module_clone_data *clone_data)
+static char *clone_submodule_sm_gitdir(const char *name)
 {
-	char *p, *sm_gitdir;
-	char *sm_alternate = NULL, *error_strategy = NULL;
 	struct strbuf sb = STRBUF_INIT;
-	struct child_process cp = CHILD_PROCESS_INIT;
+	char *sm_gitdir;
 
-	submodule_name_to_gitdir(&sb, the_repository, clone_data->name);
+	submodule_name_to_gitdir(&sb, the_repository, name);
 	sm_gitdir = absolute_pathdup(sb.buf);
-	strbuf_reset(&sb);
+	strbuf_release(&sb);
 
-	if (!is_absolute_path(clone_data->path)) {
-		strbuf_addf(&sb, "%s/%s", get_git_work_tree(), clone_data->path);
-		clone_data->path = strbuf_detach(&sb, NULL);
-	} else {
-		clone_data->path = xstrdup(clone_data->path);
-	}
+	return sm_gitdir;
+}
+
+static int clone_submodule(const struct module_clone_data *clone_data,
+			   struct string_list *reference)
+{
+	char *p;
+	char *sm_gitdir = clone_submodule_sm_gitdir(clone_data->name);
+	char *sm_alternate = NULL, *error_strategy = NULL;
+	struct child_process cp = CHILD_PROCESS_INIT;
+	const char *clone_data_path = clone_data->path;
+	char *to_free = NULL;
+
+	if (!is_absolute_path(clone_data->path))
+		clone_data_path = to_free = xstrfmt("%s/%s", get_git_work_tree(),
+						    clone_data->path);
 
 	if (validate_submodule_git_dir(sm_gitdir, clone_data->name) < 0)
 		die(_("refusing to create/use '%s' in another submodule's "
@@ -1674,7 +1663,7 @@
 		if (safe_create_leading_directories_const(sm_gitdir) < 0)
 			die(_("could not create directory '%s'"), sm_gitdir);
 
-		prepare_possible_alternates(clone_data->name, &clone_data->reference);
+		prepare_possible_alternates(clone_data->name, reference);
 
 		strvec_push(&cp.args, "clone");
 		strvec_push(&cp.args, "--no-checkout");
@@ -1684,9 +1673,10 @@
 			strvec_push(&cp.args, "--progress");
 		if (clone_data->depth && *(clone_data->depth))
 			strvec_pushl(&cp.args, "--depth", clone_data->depth, NULL);
-		if (clone_data->reference.nr) {
+		if (reference->nr) {
 			struct string_list_item *item;
-			for_each_string_list_item(item, &clone_data->reference)
+
+			for_each_string_list_item(item, reference)
 				strvec_pushl(&cp.args, "--reference",
 					     item->string, NULL);
 		}
@@ -1705,7 +1695,7 @@
 
 		strvec_push(&cp.args, "--");
 		strvec_push(&cp.args, clone_data->url);
-		strvec_push(&cp.args, clone_data->path);
+		strvec_push(&cp.args, clone_data_path);
 
 		cp.git_cmd = 1;
 		prepare_submodule_repo_env(&cp.env);
@@ -1713,23 +1703,25 @@
 
 		if(run_command(&cp))
 			die(_("clone of '%s' into submodule path '%s' failed"),
-			    clone_data->url, clone_data->path);
+			    clone_data->url, clone_data_path);
 	} else {
-		if (clone_data->require_init && !access(clone_data->path, X_OK) &&
-		    !is_empty_dir(clone_data->path))
-			die(_("directory not empty: '%s'"), clone_data->path);
-		if (safe_create_leading_directories_const(clone_data->path) < 0)
-			die(_("could not create directory '%s'"), clone_data->path);
-		strbuf_addf(&sb, "%s/index", sm_gitdir);
-		unlink_or_warn(sb.buf);
-		strbuf_reset(&sb);
+		char *path;
+
+		if (clone_data->require_init && !access(clone_data_path, X_OK) &&
+		    !is_empty_dir(clone_data_path))
+			die(_("directory not empty: '%s'"), clone_data_path);
+		if (safe_create_leading_directories_const(clone_data_path) < 0)
+			die(_("could not create directory '%s'"), clone_data_path);
+		path = xstrfmt("%s/index", sm_gitdir);
+		unlink_or_warn(path);
+		free(path);
 	}
 
-	connect_work_tree_and_git_dir(clone_data->path, sm_gitdir, 0);
+	connect_work_tree_and_git_dir(clone_data_path, sm_gitdir, 0);
 
-	p = git_pathdup_submodule(clone_data->path, "config");
+	p = git_pathdup_submodule(clone_data_path, "config");
 	if (!p)
-		die(_("could not get submodule directory for '%s'"), clone_data->path);
+		die(_("could not get submodule directory for '%s'"), clone_data_path);
 
 	/* setup alternateLocation and alternateErrorStrategy in the cloned submodule if needed */
 	git_config_get_string("submodule.alternateLocation", &sm_alternate);
@@ -1744,9 +1736,9 @@
 	free(sm_alternate);
 	free(error_strategy);
 
-	strbuf_release(&sb);
 	free(sm_gitdir);
 	free(p);
+	free(to_free);
 	return 0;
 }
 
@@ -1754,8 +1746,8 @@
 {
 	int dissociate = 0, quiet = 0, progress = 0, require_init = 0;
 	struct module_clone_data clone_data = MODULE_CLONE_DATA_INIT;
-	struct list_objects_filter_options filter_options;
-
+	struct list_objects_filter_options filter_options = { 0 };
+	struct string_list reference = STRING_LIST_INIT_NODUP;
 	struct option module_clone_options[] = {
 		OPT_STRING(0, "prefix", &clone_data.prefix,
 			   N_("path"),
@@ -1769,7 +1761,7 @@
 		OPT_STRING(0, "url", &clone_data.url,
 			   N_("string"),
 			   N_("url where to clone the submodule from")),
-		OPT_STRING_LIST(0, "reference", &clone_data.reference,
+		OPT_STRING_LIST(0, "reference", &reference,
 			   N_("repo"),
 			   N_("reference repository")),
 		OPT_BOOL(0, "dissociate", &dissociate,
@@ -1787,7 +1779,6 @@
 		OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
 		OPT_END()
 	};
-
 	const char *const git_submodule_helper_usage[] = {
 		N_("git submodule--helper clone [--prefix=<path>] [--quiet] "
 		   "[--reference <repository>] [--name <name>] [--depth <depth>] "
@@ -1796,7 +1787,6 @@
 		NULL
 	};
 
-	memset(&filter_options, 0, sizeof(filter_options));
 	argc = parse_options(argc, argv, prefix, module_clone_options,
 			     git_submodule_helper_usage, 0);
 
@@ -1810,31 +1800,33 @@
 		usage_with_options(git_submodule_helper_usage,
 				   module_clone_options);
 
-	clone_submodule(&clone_data);
+	clone_submodule(&clone_data, &reference);
 	list_objects_filter_release(&filter_options);
+	string_list_clear(&reference, 1);
 	return 0;
 }
 
-static void determine_submodule_update_strategy(struct repository *r,
-						int just_cloned,
-						const char *path,
-						const char *update,
-						struct submodule_update_strategy *out)
+static int determine_submodule_update_strategy(struct repository *r,
+					       int just_cloned,
+					       const char *path,
+					       enum submodule_update_type update,
+					       struct submodule_update_strategy *out)
 {
 	const struct submodule *sub = submodule_from_path(r, null_oid(), path);
 	char *key;
 	const char *val;
+	int ret;
 
 	key = xstrfmt("submodule.%s.update", sub->name);
 
 	if (update) {
-		if (parse_submodule_update_strategy(update, out) < 0)
-			die(_("Invalid update mode '%s' for submodule path '%s'"),
-				update, path);
+		out->type = update;
 	} else if (!repo_config_get_string_tmp(r, key, &val)) {
-		if (parse_submodule_update_strategy(val, out) < 0)
-			die(_("Invalid update mode '%s' configured for submodule path '%s'"),
-				val, path);
+		if (parse_submodule_update_strategy(val, out) < 0) {
+			ret = die_message(_("Invalid update mode '%s' configured for submodule path '%s'"),
+					  val, path);
+			goto cleanup;
+		}
 	} else if (sub->update_strategy.type != SM_UPDATE_UNSPECIFIED) {
 		if (sub->update_strategy.type == SM_UPDATE_COMMAND)
 			BUG("how did we read update = !command from .gitmodules?");
@@ -1849,7 +1841,10 @@
 	     out->type == SM_UPDATE_NONE))
 		out->type = SM_UPDATE_CHECKOUT;
 
+	ret = 0;
+cleanup:
 	free(key);
+	return ret;
 }
 
 struct update_clone_data {
@@ -1863,7 +1858,7 @@
 	int current;
 
 	/* configuration parameters which are passed on to the children */
-	struct update_data *update_data;
+	const struct update_data *update_data;
 
 	/* to be consumed by update_submodule() */
 	struct update_clone_data *update_clone;
@@ -1878,11 +1873,16 @@
 };
 #define SUBMODULE_UPDATE_CLONE_INIT { 0 }
 
+static void submodule_update_clone_release(struct submodule_update_clone *suc)
+{
+	free(suc->update_clone);
+	free(suc->failed_clones);
+}
+
 struct update_data {
 	const char *prefix;
-	const char *recursive_prefix;
-	const char *displaypath;
-	const char *update_default;
+	char *displaypath;
+	enum submodule_update_type update_default;
 	struct object_id suboid;
 	struct string_list references;
 	struct submodule_update_strategy update_strategy;
@@ -1917,6 +1917,12 @@
 	.max_jobs = 1, \
 }
 
+static void update_data_release(struct update_data *ud)
+{
+	free(ud->displaypath);
+	module_list_release(&ud->list);
+}
+
 static void next_submodule_warn_missing(struct submodule_update_clone *suc,
 		struct strbuf *out, const char *displaypath)
 {
@@ -1949,30 +1955,20 @@
 	const char *update_string;
 	enum submodule_update_type update_type;
 	char *key;
-	struct strbuf displaypath_sb = STRBUF_INIT;
+	const struct update_data *ud = suc->update_data;
+	char *displaypath = get_submodule_displaypath(ce->name, ud->prefix);
 	struct strbuf sb = STRBUF_INIT;
-	const char *displaypath = NULL;
 	int needs_cloning = 0;
 	int need_free_url = 0;
 
 	if (ce_stage(ce)) {
-		if (suc->update_data->recursive_prefix)
-			strbuf_addf(&sb, "%s/%s", suc->update_data->recursive_prefix, ce->name);
-		else
-			strbuf_addstr(&sb, ce->name);
-		strbuf_addf(out, _("Skipping unmerged submodule %s"), sb.buf);
+		strbuf_addf(out, _("Skipping unmerged submodule %s"), displaypath);
 		strbuf_addch(out, '\n');
 		goto cleanup;
 	}
 
 	sub = submodule_from_path(the_repository, null_oid(), ce->name);
 
-	if (suc->update_data->recursive_prefix)
-		displaypath = relative_path(suc->update_data->recursive_prefix,
-					    ce->name, &displaypath_sb);
-	else
-		displaypath = ce->name;
-
 	if (!sub) {
 		next_submodule_warn_missing(suc, out, displaypath);
 		goto cleanup;
@@ -2051,6 +2047,7 @@
 	strvec_pushl(&child->args, "--url", url, NULL);
 	if (suc->update_data->references.nr) {
 		struct string_list_item *item;
+
 		for_each_string_list_item(item, &suc->update_data->references)
 			strvec_pushl(&child->args, "--reference", item->string, NULL);
 	}
@@ -2062,7 +2059,7 @@
 					      "--no-single-branch");
 
 cleanup:
-	strbuf_release(&displaypath_sb);
+	free(displaypath);
 	strbuf_release(&sb);
 	if (need_free_url)
 		free((void*)url);
@@ -2083,6 +2080,7 @@
 		ce = suc->update_data->list.entries[suc->current];
 		if (prepare_to_clone_next_submodule(ce, child, suc, err)) {
 			int *p = xmalloc(sizeof(*p));
+
 			*p = suc->current;
 			*idx_task_cb = p;
 			suc->current++;
@@ -2098,6 +2096,7 @@
 	index = suc->current - suc->update_data->list.nr;
 	if (index < suc->failed_clones_nr) {
 		int *p;
+
 		ce = suc->failed_clones[index];
 		if (!prepare_to_clone_next_submodule(ce, child, suc, err)) {
 			suc->current ++;
@@ -2121,6 +2120,7 @@
 				      void *idx_task_cb)
 {
 	struct submodule_update_clone *suc = suc_cb;
+
 	suc->quickstop = 1;
 	return 1;
 }
@@ -2132,9 +2132,9 @@
 {
 	const struct cache_entry *ce;
 	struct submodule_update_clone *suc = suc_cb;
-
 	int *idxP = idx_task_cb;
 	int idx = *idxP;
+
 	free(idxP);
 
 	if (!result)
@@ -2167,19 +2167,20 @@
 				   void *cb)
 {
 	int *max_jobs = cb;
+
 	if (!strcmp(var, "submodule.fetchjobs"))
 		*max_jobs = parse_submodule_fetchjobs(var, value);
 	return 0;
 }
 
-static int is_tip_reachable(const char *path, struct object_id *oid)
+static int is_tip_reachable(const char *path, const struct object_id *oid)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 	struct strbuf rev = STRBUF_INIT;
 	char *hex = oid_to_hex(oid);
 
 	cp.git_cmd = 1;
-	cp.dir = xstrdup(path);
+	cp.dir = path;
 	cp.no_stderr = 1;
 	strvec_pushl(&cp.args, "rev-list", "-n", "1", hex, "--not", "--all", NULL);
 
@@ -2191,13 +2192,14 @@
 	return 1;
 }
 
-static int fetch_in_submodule(const char *module_path, int depth, int quiet, struct object_id *oid)
+static int fetch_in_submodule(const char *module_path, int depth, int quiet,
+			      const struct object_id *oid)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 
 	prepare_submodule_repo_env(&cp.env);
 	cp.git_cmd = 1;
-	cp.dir = xstrdup(module_path);
+	cp.dir = module_path;
 
 	strvec_push(&cp.args, "fetch");
 	if (quiet)
@@ -2207,6 +2209,7 @@
 	if (oid) {
 		char *hex = oid_to_hex(oid);
 		char *remote = get_default_remote();
+
 		strvec_pushl(&cp.args, remote, hex, NULL);
 		free(remote);
 	}
@@ -2214,11 +2217,11 @@
 	return run_command(&cp);
 }
 
-static int run_update_command(struct update_data *ud, int subforce)
+static int run_update_command(const struct update_data *ud, int subforce)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 	char *oid = oid_to_hex(&ud->oid);
-	int must_die_on_failure = 0;
+	int ret;
 
 	switch (ud->update_strategy.type) {
 	case SM_UPDATE_CHECKOUT:
@@ -2232,55 +2235,50 @@
 		strvec_push(&cp.args, "rebase");
 		if (ud->quiet)
 			strvec_push(&cp.args, "--quiet");
-		must_die_on_failure = 1;
 		break;
 	case SM_UPDATE_MERGE:
 		cp.git_cmd = 1;
 		strvec_push(&cp.args, "merge");
 		if (ud->quiet)
 			strvec_push(&cp.args, "--quiet");
-		must_die_on_failure = 1;
 		break;
 	case SM_UPDATE_COMMAND:
 		cp.use_shell = 1;
 		strvec_push(&cp.args, ud->update_strategy.command);
-		must_die_on_failure = 1;
 		break;
 	default:
-		BUG("unexpected update strategy type: %s",
-		    submodule_strategy_to_string(&ud->update_strategy));
+		BUG("unexpected update strategy type: %d",
+		    ud->update_strategy.type);
 	}
 	strvec_push(&cp.args, oid);
 
-	cp.dir = xstrdup(ud->sm_path);
+	cp.dir = ud->sm_path;
 	prepare_submodule_repo_env(&cp.env);
-	if (run_command(&cp)) {
+	if ((ret = run_command(&cp))) {
 		switch (ud->update_strategy.type) {
 		case SM_UPDATE_CHECKOUT:
 			die_message(_("Unable to checkout '%s' in submodule path '%s'"),
 				    oid, ud->displaypath);
+			/* No "ret" assignment, use "git checkout"'s */
 			break;
 		case SM_UPDATE_REBASE:
-			die_message(_("Unable to rebase '%s' in submodule path '%s'"),
-			    oid, ud->displaypath);
+			ret = die_message(_("Unable to rebase '%s' in submodule path '%s'"),
+					  oid, ud->displaypath);
 			break;
 		case SM_UPDATE_MERGE:
-			die_message(_("Unable to merge '%s' in submodule path '%s'"),
-			    oid, ud->displaypath);
+			ret = die_message(_("Unable to merge '%s' in submodule path '%s'"),
+					  oid, ud->displaypath);
 			break;
 		case SM_UPDATE_COMMAND:
-			die_message(_("Execution of '%s %s' failed in submodule path '%s'"),
-			    ud->update_strategy.command, oid, ud->displaypath);
+			ret = die_message(_("Execution of '%s %s' failed in submodule path '%s'"),
+					  ud->update_strategy.command, oid, ud->displaypath);
 			break;
 		default:
-			BUG("unexpected update strategy type: %s",
-			    submodule_strategy_to_string(&ud->update_strategy));
+			BUG("unexpected update strategy type: %d",
+			    ud->update_strategy.type);
 		}
-		if (must_die_on_failure)
-			exit(128);
 
-		/* the command failed, but update must continue */
-		return 1;
+		return ret;
 	}
 
 	if (ud->quiet)
@@ -2304,14 +2302,14 @@
 		       ud->displaypath, ud->update_strategy.command, oid);
 		break;
 	default:
-		BUG("unexpected update strategy type: %s",
-		    submodule_strategy_to_string(&ud->update_strategy));
+		BUG("unexpected update strategy type: %d",
+		    ud->update_strategy.type);
 	}
 
 	return 0;
 }
 
-static int run_update_procedure(struct update_data *ud)
+static int run_update_procedure(const struct update_data *ud)
 {
 	int subforce = is_null_oid(&ud->suboid) || ud->force;
 
@@ -2333,59 +2331,67 @@
 		 */
 		if (!is_tip_reachable(ud->sm_path, &ud->oid) &&
 		    fetch_in_submodule(ud->sm_path, ud->depth, ud->quiet, &ud->oid))
-			die(_("Fetched in submodule path '%s', but it did not "
-			      "contain %s. Direct fetching of that commit failed."),
-			    ud->displaypath, oid_to_hex(&ud->oid));
+			return die_message(_("Fetched in submodule path '%s', but it did not "
+					     "contain %s. Direct fetching of that commit failed."),
+					   ud->displaypath, oid_to_hex(&ud->oid));
 	}
 
 	return run_update_command(ud, subforce);
 }
 
-static const char *remote_submodule_branch(const char *path)
+static int remote_submodule_branch(const char *path, const char **branch)
 {
 	const struct submodule *sub;
-	const char *branch = NULL;
 	char *key;
+	*branch = NULL;
 
 	sub = submodule_from_path(the_repository, null_oid(), path);
 	if (!sub)
-		return NULL;
+		return die_message(_("could not initialize submodule at path '%s'"),
+				   path);
 
 	key = xstrfmt("submodule.%s.branch", sub->name);
-	if (repo_config_get_string_tmp(the_repository, key, &branch))
-		branch = sub->branch;
+	if (repo_config_get_string_tmp(the_repository, key, branch))
+		*branch = sub->branch;
 	free(key);
 
-	if (!branch)
-		return "HEAD";
+	if (!*branch) {
+		*branch = "HEAD";
+		return 0;
+	}
 
-	if (!strcmp(branch, ".")) {
+	if (!strcmp(*branch, ".")) {
 		const char *refname = resolve_ref_unsafe("HEAD", 0, NULL, NULL);
 
 		if (!refname)
-			die(_("No such ref: %s"), "HEAD");
+			return die_message(_("No such ref: %s"), "HEAD");
 
 		/* detached HEAD */
 		if (!strcmp(refname, "HEAD"))
-			die(_("Submodule (%s) branch configured to inherit "
-			      "branch from superproject, but the superproject "
-			      "is not on any branch"), sub->name);
+			return die_message(_("Submodule (%s) branch configured to inherit "
+					     "branch from superproject, but the superproject "
+					     "is not on any branch"), sub->name);
 
 		if (!skip_prefix(refname, "refs/heads/", &refname))
-			die(_("Expecting a full ref name, got %s"), refname);
-		return refname;
+			return die_message(_("Expecting a full ref name, got %s"),
+					   refname);
+
+		*branch = refname;
+		return 0;
 	}
 
-	return branch;
+	/* Our "branch" is coming from repo_config_get_string_tmp() */
+	return 0;
 }
 
-static void ensure_core_worktree(const char *path)
+static int ensure_core_worktree(const char *path)
 {
 	const char *cw;
 	struct repository subrepo;
 
 	if (repo_submodule_init(&subrepo, the_repository, path, null_oid()))
-		die(_("could not get a repository handle for submodule '%s'"), path);
+		return die_message(_("could not get a repository handle for submodule '%s'"),
+				   path);
 
 	if (!repo_config_get_string_tmp(&subrepo, "core.worktree", &cw)) {
 		char *cfg_file, *abs_path;
@@ -2403,15 +2409,39 @@
 		free(abs_path);
 		strbuf_release(&sb);
 	}
+
+	repo_clear(&subrepo);
+	return 0;
 }
 
-static void update_data_to_args(struct update_data *update_data, struct strvec *args)
+static const char *submodule_update_type_to_label(enum submodule_update_type type)
 {
+	switch (type) {
+	case SM_UPDATE_CHECKOUT:
+		return "checkout";
+	case SM_UPDATE_MERGE:
+		return "merge";
+	case SM_UPDATE_REBASE:
+		return "rebase";
+	case SM_UPDATE_UNSPECIFIED:
+	case SM_UPDATE_NONE:
+	case SM_UPDATE_COMMAND:
+		break;
+	}
+	BUG("unreachable with type %d", type);
+}
+
+static void update_data_to_args(const struct update_data *update_data,
+				struct strvec *args)
+{
+	enum submodule_update_type update_type = update_data->update_default;
+
+	if (update_data->displaypath) {
+		strvec_push(args, "--super-prefix");
+		strvec_pushf(args, "%s/", update_data->displaypath);
+	}
 	strvec_pushl(args, "submodule--helper", "update", "--recursive", NULL);
 	strvec_pushf(args, "--jobs=%d", update_data->max_jobs);
-	if (update_data->recursive_prefix)
-		strvec_pushl(args, "--recursive-prefix",
-			     update_data->recursive_prefix, NULL);
 	if (update_data->quiet)
 		strvec_push(args, "--quiet");
 	if (update_data->force)
@@ -2430,10 +2460,13 @@
 		strvec_push(args, "--require-init");
 	if (update_data->depth)
 		strvec_pushf(args, "--depth=%d", update_data->depth);
-	if (update_data->update_default)
-		strvec_pushl(args, "--update", update_data->update_default, NULL);
+	if (update_type != SM_UPDATE_UNSPECIFIED)
+		strvec_pushf(args, "--%s",
+			     submodule_update_type_to_label(update_type));
+
 	if (update_data->references.nr) {
 		struct string_list_item *item;
+
 		for_each_string_list_item(item, &update_data->references)
 			strvec_pushl(args, "--reference", item->string, NULL);
 	}
@@ -2453,66 +2486,62 @@
 
 static int update_submodule(struct update_data *update_data)
 {
-	char *prefixed_path;
+	int ret;
 
-	ensure_core_worktree(update_data->sm_path);
-
-	if (update_data->recursive_prefix)
-		prefixed_path = xstrfmt("%s%s", update_data->recursive_prefix,
-					update_data->sm_path);
-	else
-		prefixed_path = xstrdup(update_data->sm_path);
-
-	update_data->displaypath = get_submodule_displaypath(prefixed_path,
-							     update_data->prefix);
-	free(prefixed_path);
-
-	determine_submodule_update_strategy(the_repository, update_data->just_cloned,
-					    update_data->sm_path, update_data->update_default,
-					    &update_data->update_strategy);
+	ret = determine_submodule_update_strategy(the_repository,
+						  update_data->just_cloned,
+						  update_data->sm_path,
+						  update_data->update_default,
+						  &update_data->update_strategy);
+	if (ret)
+		return ret;
 
 	if (update_data->just_cloned)
 		oidcpy(&update_data->suboid, null_oid());
 	else if (resolve_gitlink_ref(update_data->sm_path, "HEAD", &update_data->suboid))
-		die(_("Unable to find current revision in submodule path '%s'"),
-			update_data->displaypath);
+		return die_message(_("Unable to find current revision in submodule path '%s'"),
+				   update_data->displaypath);
 
 	if (update_data->remote) {
-		char *remote_name = get_default_remote_submodule(update_data->sm_path);
-		const char *branch = remote_submodule_branch(update_data->sm_path);
-		char *remote_ref = xstrfmt("refs/remotes/%s/%s", remote_name, branch);
+		char *remote_name;
+		const char *branch;
+		char *remote_ref;
+		int code;
+
+		code = get_default_remote_submodule(update_data->sm_path, &remote_name);
+		if (code)
+			return code;
+		code = remote_submodule_branch(update_data->sm_path, &branch);
+		if (code)
+			return code;
+		remote_ref = xstrfmt("refs/remotes/%s/%s", remote_name, branch);
+
+		free(remote_name);
 
 		if (!update_data->nofetch) {
 			if (fetch_in_submodule(update_data->sm_path, update_data->depth,
 					      0, NULL))
-				die(_("Unable to fetch in submodule path '%s'"),
-				    update_data->sm_path);
+				return die_message(_("Unable to fetch in submodule path '%s'"),
+						   update_data->sm_path);
 		}
 
 		if (resolve_gitlink_ref(update_data->sm_path, remote_ref, &update_data->oid))
-			die(_("Unable to find %s revision in submodule path '%s'"),
-			    remote_ref, update_data->sm_path);
+			return die_message(_("Unable to find %s revision in submodule path '%s'"),
+					   remote_ref, update_data->sm_path);
 
 		free(remote_ref);
 	}
 
-	if (!oideq(&update_data->oid, &update_data->suboid) || update_data->force)
-		if (run_update_procedure(update_data))
-			return 1;
+	if (!oideq(&update_data->oid, &update_data->suboid) || update_data->force) {
+		ret = run_update_procedure(update_data);
+		if (ret)
+			return ret;
+	}
 
 	if (update_data->recursive) {
 		struct child_process cp = CHILD_PROCESS_INIT;
 		struct update_data next = *update_data;
-		int res;
 
-		if (update_data->recursive_prefix)
-			prefixed_path = xstrfmt("%s%s/", update_data->recursive_prefix,
-						update_data->sm_path);
-		else
-			prefixed_path = xstrfmt("%s/", update_data->sm_path);
-
-		next.recursive_prefix = get_submodule_displaypath(prefixed_path,
-								  update_data->prefix);
 		next.prefix = NULL;
 		oidcpy(&next.oid, null_oid());
 		oidcpy(&next.suboid, null_oid());
@@ -2522,16 +2551,11 @@
 		prepare_submodule_repo_env(&cp.env);
 		update_data_to_args(&next, &cp.args);
 
-		/* die() if child process die()'d */
-		res = run_command(&cp);
-		if (!res)
-			return 0;
-		die_message(_("Failed to recurse into submodule path '%s'"),
-			    update_data->displaypath);
-		if (res == 128)
-			exit(res);
-		else if (res)
-			return 1;
+		ret = run_command(&cp);
+		if (ret)
+			die_message(_("Failed to recurse into submodule path '%s'"),
+				    update_data->displaypath);
+		return ret;
 	}
 
 	return 0;
@@ -2539,7 +2563,7 @@
 
 static int update_submodules(struct update_data *update_data)
 {
-	int i, res = 0;
+	int i, ret = 0;
 	struct submodule_update_clone suc = SUBMODULE_UPDATE_CLONE_INIT;
 
 	suc.update_data = update_data;
@@ -2557,33 +2581,47 @@
 	 * - the listener can avoid doing any work if fetching failed.
 	 */
 	if (suc.quickstop) {
-		res = 1;
+		ret = 1;
 		goto cleanup;
 	}
 
 	for (i = 0; i < suc.update_clone_nr; i++) {
 		struct update_clone_data ucd = suc.update_clone[i];
+		int code;
 
 		oidcpy(&update_data->oid, &ucd.oid);
 		update_data->just_cloned = ucd.just_cloned;
 		update_data->sm_path = ucd.sub->path;
 
-		if (update_submodule(update_data))
-			res = 1;
+		code = ensure_core_worktree(update_data->sm_path);
+		if (code)
+			goto fail;
+
+		update_data->displaypath = get_submodule_displaypath(
+			update_data->sm_path, update_data->prefix);
+		code = update_submodule(update_data);
+		FREE_AND_NULL(update_data->displaypath);
+fail:
+		if (!code)
+			continue;
+		ret = code;
+		if (ret == 128)
+			goto cleanup;
 	}
 
 cleanup:
+	submodule_update_clone_release(&suc);
 	string_list_clear(&update_data->references, 0);
-	return res;
+	return ret;
 }
 
 static int module_update(int argc, const char **argv, const char *prefix)
 {
-	struct pathspec pathspec;
+	struct pathspec pathspec = { 0 };
+	struct pathspec pathspec2 = { 0 };
 	struct update_data opt = UPDATE_DATA_INIT;
-	struct list_objects_filter_options filter_options;
+	struct list_objects_filter_options filter_options = { 0 };
 	int ret;
-
 	struct option module_update_options[] = {
 		OPT__FORCE(&opt.force, N_("force checkout updates"), 0),
 		OPT_BOOL(0, "init", &opt.init,
@@ -2597,13 +2635,15 @@
 		OPT_STRING(0, "prefix", &opt.prefix,
 			   N_("path"),
 			   N_("path into the working tree")),
-		OPT_STRING(0, "recursive-prefix", &opt.recursive_prefix,
-			   N_("path"),
-			   N_("path into the working tree, across nested "
-			      "submodule boundaries")),
-		OPT_STRING(0, "update", &opt.update_default,
-			   N_("string"),
-			   N_("rebase, merge, checkout or none")),
+		OPT_SET_INT(0, "checkout", &opt.update_default,
+			N_("use the 'checkout' update strategy (default)"),
+			SM_UPDATE_CHECKOUT),
+		OPT_SET_INT('m', "merge", &opt.update_default,
+			N_("use the 'merge' update strategy"),
+			SM_UPDATE_MERGE),
+		OPT_SET_INT('r', "rebase", &opt.update_default,
+			N_("use the 'rebase' update strategy"),
+			SM_UPDATE_REBASE),
 		OPT_STRING_LIST(0, "reference", &opt.references, N_("repo"),
 			   N_("reference repository")),
 		OPT_BOOL(0, "dissociate", &opt.dissociate,
@@ -2619,13 +2659,12 @@
 		OPT_BOOL(0, "progress", &opt.progress,
 			    N_("force cloning progress")),
 		OPT_BOOL(0, "require-init", &opt.require_init,
-			   N_("disallow cloning into non-empty directory")),
+			   N_("disallow cloning into non-empty directory, implies --init")),
 		OPT_BOOL(0, "single-branch", &opt.single_branch,
 			 N_("clone only one branch, HEAD or --branch")),
 		OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
 		OPT_END()
 	};
-
 	const char *const git_submodule_helper_usage[] = {
 		N_("git submodule [--quiet] update"
 		" [--init [--filter=<filter-spec>]] [--remote]"
@@ -2639,10 +2678,12 @@
 	update_clone_config_from_gitmodules(&opt.max_jobs);
 	git_config(git_update_clone_config, &opt.max_jobs);
 
-	memset(&filter_options, 0, sizeof(filter_options));
 	argc = parse_options(argc, argv, prefix, module_update_options,
 			     git_submodule_helper_usage, 0);
 
+	if (opt.require_init)
+		opt.init = 1;
+
 	if (filter_options.choice && !opt.init) {
 		usage_with_options(git_submodule_helper_usage,
 				   module_update_options);
@@ -2651,13 +2692,11 @@
 	opt.filter_options = &filter_options;
 
 	if (opt.update_default)
-		if (parse_submodule_update_strategy(opt.update_default,
-						    &opt.update_strategy) < 0)
-			die(_("bad value for update parameter"));
+		opt.update_strategy.type = opt.update_default;
 
 	if (module_list_compute(argc, argv, prefix, &pathspec, &opt.list) < 0) {
-		list_objects_filter_release(&filter_options);
-		return 1;
+		ret = 1;
+		goto cleanup;
 	}
 
 	if (pathspec.nr)
@@ -2668,8 +2707,11 @@
 		struct init_cb info = INIT_CB_INIT;
 
 		if (module_list_compute(argc, argv, opt.prefix,
-					&pathspec, &list) < 0)
-			return 1;
+					&pathspec2, &list) < 0) {
+			module_list_release(&list);
+			ret = 1;
+			goto cleanup;
+		}
 
 		/*
 		 * If there are no path args and submodule.active is set then,
@@ -2679,15 +2721,19 @@
 			module_list_active(&list);
 
 		info.prefix = opt.prefix;
-		info.superprefix = opt.recursive_prefix;
 		if (opt.quiet)
 			info.flags |= OPT_QUIET;
 
 		for_each_listed_submodule(&list, init_submodule_cb, &info);
+		module_list_release(&list);
 	}
 
 	ret = update_submodules(&opt);
+cleanup:
+	update_data_release(&opt);
 	list_objects_filter_release(&filter_options);
+	clear_pathspec(&pathspec);
+	clear_pathspec(&pathspec2);
 	return ret;
 }
 
@@ -2771,10 +2817,9 @@
 static int absorb_git_dirs(int argc, const char **argv, const char *prefix)
 {
 	int i;
-	struct pathspec pathspec;
+	struct pathspec pathspec = { 0 };
 	struct module_list list = MODULE_LIST_INIT;
 	unsigned flags = ABSORB_GITDIR_RECURSE_SUBMODULES;
-
 	struct option embed_gitdir_options[] = {
 		OPT_STRING(0, "prefix", &prefix,
 			   N_("path"),
@@ -2783,53 +2828,26 @@
 			ABSORB_GITDIR_RECURSE_SUBMODULES),
 		OPT_END()
 	};
-
 	const char *const git_submodule_helper_usage[] = {
-		N_("git submodule--helper absorb-git-dirs [<options>] [<path>...]"),
+		N_("git submodule absorbgitdirs [<options>] [<path>...]"),
 		NULL
 	};
+	int ret = 1;
 
 	argc = parse_options(argc, argv, prefix, embed_gitdir_options,
 			     git_submodule_helper_usage, 0);
 
 	if (module_list_compute(argc, argv, prefix, &pathspec, &list) < 0)
-		return 1;
+		goto cleanup;
 
 	for (i = 0; i < list.nr; i++)
 		absorb_git_dir_into_superproject(list.entries[i]->name, flags);
 
-	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");
-
-	return !is_submodule_active(the_repository, argv[1]);
-}
-
-/*
- * Exit non-zero if any of the submodule names given on the command line is
- * invalid. If no names are given, filter stdin to print only valid names
- * (which is primarily intended for testing).
- */
-static int check_name(int argc, const char **argv, const char *prefix)
-{
-	if (argc > 1) {
-		while (*++argv) {
-			if (check_submodule_name(*argv) < 0)
-				return 1;
-		}
-	} else {
-		struct strbuf buf = STRBUF_INIT;
-		while (strbuf_getline(&buf, stdin) != EOF) {
-			if (!check_submodule_name(buf.buf))
-				printf("%s\n", buf.buf);
-		}
-		strbuf_release(&buf);
-	}
-	return 0;
+	ret = 0;
+cleanup:
+	clear_pathspec(&pathspec);
+	module_list_release(&list);
+	return ret;
 }
 
 static int module_config(int argc, const char **argv, const char *prefix)
@@ -2838,7 +2856,6 @@
 		CHECK_WRITEABLE = 1,
 		DO_UNSET = 2
 	} command = 0;
-
 	struct option module_config_options[] = {
 		OPT_CMDMODE(0, "check-writeable", &command,
 			    N_("check if it is safe to write to the .gitmodules file"),
@@ -2884,13 +2901,12 @@
 	const char *newurl;
 	const char *path;
 	char *config_name;
-
 	struct option options[] = {
 		OPT__QUIET(&quiet, N_("suppress output for setting url of a submodule")),
 		OPT_END()
 	};
 	const char *const usage[] = {
-		N_("git submodule--helper set-url [--quiet] <path> <newurl>"),
+		N_("git submodule set-url [--quiet] <path> <newurl>"),
 		NULL
 	};
 
@@ -2915,13 +2931,13 @@
 	const char *opt_branch = NULL;
 	const char *path;
 	char *config_name;
-
-	/*
-	 * We accept the `quiet` option for uniformity across subcommands,
-	 * though there is nothing to make less verbose in this subcommand.
-	 */
 	struct option options[] = {
+		/*
+		 * We accept the `quiet` option for uniformity across subcommands,
+		 * though there is nothing to make less verbose in this subcommand.
+		 */
 		OPT_NOOP_NOARG('q', "quiet"),
+
 		OPT_BOOL('d', "default", &opt_default,
 			N_("set the default tracking branch to master")),
 		OPT_STRING('b', "branch", &opt_branch, N_("branch"),
@@ -2929,8 +2945,8 @@
 		OPT_END()
 	};
 	const char *const usage[] = {
-		N_("git submodule--helper set-branch [-q|--quiet] (-d|--default) <path>"),
-		N_("git submodule--helper set-branch [-q|--quiet] (-b|--branch) <branch> <path>"),
+		N_("git submodule set-branch [-q|--quiet] (-d|--default) <path>"),
+		N_("git submodule set-branch [-q|--quiet] (-b|--branch) <branch> <path>"),
 		NULL
 	};
 
@@ -2956,7 +2972,6 @@
 {
 	enum branch_track track;
 	int quiet = 0, force = 0, reflog = 0, dry_run = 0;
-
 	struct option options[] = {
 		OPT__QUIET(&quiet, N_("print only error messages")),
 		OPT__FORCE(&force, N_("force creation"), 0),
@@ -3019,8 +3034,10 @@
 	if (!capture_command(&cp_remote, &sb_remote_out, 0)) {
 		char *next_line;
 		char *line = sb_remote_out.buf;
+
 		while ((next_line = strchr(line, '\n')) != NULL) {
 			size_t len = next_line - line;
+
 			if (strip_suffix_mem(line, &len, " (fetch)"))
 				strbuf_addf(msg, "  %.*s\n", (int)len, line);
 			line = next_line + 1;
@@ -3034,6 +3051,8 @@
 {
 	char *submod_gitdir_path;
 	struct module_clone_data clone_data = MODULE_CLONE_DATA_INIT;
+	struct string_list reference = STRING_LIST_INIT_NODUP;
+	int ret = -1;
 
 	/* perhaps the path already exists and is already a git repo, else clone it */
 	if (is_directory(add_data->sm_path)) {
@@ -3050,6 +3069,7 @@
 		free(submod_gitdir_path);
 	} else {
 		struct child_process cp = CHILD_PROCESS_INIT;
+
 		submod_gitdir_path = xstrfmt(".git/modules/%s", add_data->sm_name);
 
 		if (is_directory(submod_gitdir_path)) {
@@ -3088,15 +3108,17 @@
 		clone_data.url = add_data->realrepo;
 		clone_data.quiet = add_data->quiet;
 		clone_data.progress = add_data->progress;
-		if (add_data->reference_path)
-			string_list_append(&clone_data.reference,
-					   xstrdup(add_data->reference_path));
+		if (add_data->reference_path) {
+			char *p = xstrdup(add_data->reference_path);
+
+			string_list_append(&reference, p)->util = p;
+		}
 		clone_data.dissociate = add_data->dissociate;
 		if (add_data->depth >= 0)
 			clone_data.depth = xstrfmt("%d", add_data->depth);
 
-		if (clone_submodule(&clone_data))
-			return -1;
+		if (clone_submodule(&clone_data, &reference))
+			goto cleanup;
 
 		prepare_submodule_repo_env(&cp.env);
 		cp.git_cmd = 1;
@@ -3115,7 +3137,10 @@
 		if (run_command(&cp))
 			die(_("unable to checkout submodule '%s'"), add_data->sm_path);
 	}
-	return 0;
+	ret = 0;
+cleanup:
+	string_list_clear(&reference, 1);
+	return ret;
 }
 
 static int config_submodule_in_gitmodules(const char *name, const char *var, const char *value)
@@ -3136,7 +3161,7 @@
 static void configure_added_submodule(struct add_data *add_data)
 {
 	char *key;
-	char *val = NULL;
+	const char *val;
 	struct child_process add_submod = CHILD_PROCESS_INIT;
 	struct child_process add_gitmodules = CHILD_PROCESS_INIT;
 
@@ -3181,7 +3206,7 @@
 	 * is_submodule_active(), since that function needs to find
 	 * out the value of "submodule.active" again anyway.
 	 */
-	if (!git_config_get_string("submodule.active", &val) && val) {
+	if (!git_config_get_string_tmp("submodule.active", &val)) {
 		/*
 		 * If the submodule being added isn't already covered by the
 		 * current configured pathspec, set the submodule's active flag
@@ -3255,7 +3280,6 @@
 	int force = 0, quiet = 0, progress = 0, dissociate = 0;
 	struct add_data add_data = ADD_DATA_INIT;
 	char *to_free = NULL;
-
 	struct option options[] = {
 		OPT_STRING('b', "branch", &add_data.branch, N_("branch"),
 			   N_("branch of repository to add as submodule")),
@@ -3272,11 +3296,12 @@
 		OPT_INTEGER(0, "depth", &add_data.depth, N_("depth for shallow clones")),
 		OPT_END()
 	};
-
 	const char *const usage[] = {
-		N_("git submodule--helper add [<options>] [--] <repository> [<path>]"),
+		N_("git submodule add [<options>] [--] <repository> [<path>]"),
 		NULL
 	};
+	struct strbuf sb = STRBUF_INIT;
+	int ret = 1;
 
 	argc = parse_options(argc, argv, prefix, options, usage, 0);
 
@@ -3296,8 +3321,12 @@
 	else
 		add_data.sm_path = xstrdup(argv[1]);
 
-	if (prefix && *prefix && !is_absolute_path(add_data.sm_path))
-		add_data.sm_path = xstrfmt("%s%s", prefix, add_data.sm_path);
+	if (prefix && *prefix && !is_absolute_path(add_data.sm_path)) {
+		char *sm_path = add_data.sm_path;
+
+		add_data.sm_path = xstrfmt("%s%s", prefix, sm_path);
+		free(sm_path);
+	}
 
 	if (starts_with_dot_dot_slash(add_data.repo) ||
 	    starts_with_dot_slash(add_data.repo)) {
@@ -3326,20 +3355,17 @@
 	die_on_repo_without_commits(add_data.sm_path);
 
 	if (!force) {
-		int exit_code = -1;
-		struct strbuf sb = STRBUF_INIT;
 		struct child_process cp = CHILD_PROCESS_INIT;
+
 		cp.git_cmd = 1;
 		cp.no_stdout = 1;
 		strvec_pushl(&cp.args, "add", "--dry-run", "--ignore-missing",
 			     "--no-warn-embedded-repo", add_data.sm_path, NULL);
-		if ((exit_code = pipe_command(&cp, NULL, 0, NULL, 0, &sb, 0))) {
+		if ((ret = pipe_command(&cp, NULL, 0, NULL, 0, &sb, 0))) {
 			strbuf_complete_line(&sb);
 			fputs(sb.buf, stderr);
-			free(add_data.sm_path);
-			return exit_code;
+			goto cleanup;
 		}
-		strbuf_release(&sb);
 	}
 
 	if(!add_data.sm_name)
@@ -3354,15 +3380,17 @@
 	add_data.progress = !!progress;
 	add_data.dissociate = !!dissociate;
 
-	if (add_submodule(&add_data)) {
-		free(add_data.sm_path);
-		return 1;
-	}
+	if (add_submodule(&add_data))
+		goto cleanup;
 	configure_added_submodule(&add_data);
+
+	ret = 0;
+cleanup:
 	free(add_data.sm_path);
 	free(to_free);
+	strbuf_release(&sb);
 
-	return 0;
+	return ret;
 }
 
 #define SUPPORT_SUPER_PREFIX (1<<0)
@@ -3374,22 +3402,17 @@
 };
 
 static struct cmd_struct commands[] = {
-	{"list", module_list, 0},
-	{"name", module_name, 0},
-	{"clone", module_clone, 0},
-	{"add", module_add, SUPPORT_SUPER_PREFIX},
-	{"update", module_update, 0},
-	{"resolve-relative-url-test", resolve_relative_url_test, 0},
+	{"clone", module_clone, SUPPORT_SUPER_PREFIX},
+	{"add", module_add, 0},
+	{"update", module_update, SUPPORT_SUPER_PREFIX},
 	{"foreach", module_foreach, SUPPORT_SUPER_PREFIX},
-	{"init", module_init, SUPPORT_SUPER_PREFIX},
+	{"init", module_init, 0},
 	{"status", module_status, SUPPORT_SUPER_PREFIX},
 	{"sync", module_sync, SUPPORT_SUPER_PREFIX},
 	{"deinit", module_deinit, 0},
-	{"summary", module_summary, SUPPORT_SUPER_PREFIX},
+	{"summary", module_summary, 0},
 	{"push-check", push_check, 0},
-	{"absorb-git-dirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
-	{"is-active", is_active, 0},
-	{"check-name", check_name, 0},
+	{"absorbgitdirs", absorb_git_dirs, SUPPORT_SUPER_PREFIX},
 	{"config", module_config, 0},
 	{"set-url", module_set_url, 0},
 	{"set-branch", module_set_branch, 0},
diff --git a/builtin/symbolic-ref.c b/builtin/symbolic-ref.c
index e547a08..1b0f102 100644
--- a/builtin/symbolic-ref.c
+++ b/builtin/symbolic-ref.c
@@ -71,6 +71,8 @@
 		if (!strcmp(argv[0], "HEAD") &&
 		    !starts_with(argv[1], "refs/"))
 			die("Refusing to point HEAD outside of refs/");
+		if (check_refname_format(argv[1], REFNAME_ALLOW_ONELEVEL) < 0)
+			die("Refusing to set '%s' to invalid ref '%s'", argv[0], argv[1]);
 		ret = !!create_symref(argv[0], argv[1], msg);
 		break;
 	default:
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
index 56d05e2..43789b8 100644
--- a/builtin/unpack-objects.c
+++ b/builtin/unpack-objects.c
@@ -97,15 +97,27 @@
 	display_throughput(progress, consumed_bytes);
 }
 
+/*
+ * Decompress zstream from the standard input into a newly
+ * allocated buffer of specified size and return the buffer.
+ * The caller is responsible to free the returned buffer.
+ *
+ * But for dry_run mode, "get_data()" is only used to check the
+ * integrity of data, and the returned buffer is not used at all.
+ * Therefore, in dry_run mode, "get_data()" will release the small
+ * allocated buffer which is reused to hold temporary zstream output
+ * and return NULL instead of returning garbage data.
+ */
 static void *get_data(unsigned long size)
 {
 	git_zstream stream;
-	void *buf = xmallocz(size);
+	unsigned long bufsize = dry_run && size > 8192 ? 8192 : size;
+	void *buf = xmallocz(bufsize);
 
 	memset(&stream, 0, sizeof(stream));
 
 	stream.next_out = buf;
-	stream.avail_out = size;
+	stream.avail_out = bufsize;
 	stream.next_in = fill(1);
 	stream.avail_in = len;
 	git_inflate_init(&stream);
@@ -125,8 +137,17 @@
 		}
 		stream.next_in = fill(1);
 		stream.avail_in = len;
+		if (dry_run) {
+			/* reuse the buffer in dry_run mode */
+			stream.next_out = buf;
+			stream.avail_out = bufsize > size - stream.total_out ?
+						   size - stream.total_out :
+						   bufsize;
+		}
 	}
 	git_inflate_end(&stream);
+	if (dry_run)
+		FREE_AND_NULL(buf);
 	return buf;
 }
 
@@ -326,10 +347,70 @@
 {
 	void *buf = get_data(size);
 
-	if (!dry_run && buf)
+	if (buf)
 		write_object(nr, type, buf, size);
-	else
-		free(buf);
+}
+
+struct input_zstream_data {
+	git_zstream *zstream;
+	unsigned char buf[8192];
+	int status;
+};
+
+static const void *feed_input_zstream(struct input_stream *in_stream,
+				      unsigned long *readlen)
+{
+	struct input_zstream_data *data = in_stream->data;
+	git_zstream *zstream = data->zstream;
+	void *in = fill(1);
+
+	if (in_stream->is_finished) {
+		*readlen = 0;
+		return NULL;
+	}
+
+	zstream->next_out = data->buf;
+	zstream->avail_out = sizeof(data->buf);
+	zstream->next_in = in;
+	zstream->avail_in = len;
+
+	data->status = git_inflate(zstream, 0);
+
+	in_stream->is_finished = data->status != Z_OK;
+	use(len - zstream->avail_in);
+	*readlen = sizeof(data->buf) - zstream->avail_out;
+
+	return data->buf;
+}
+
+static void stream_blob(unsigned long size, unsigned nr)
+{
+	git_zstream zstream = { 0 };
+	struct input_zstream_data data = { 0 };
+	struct input_stream in_stream = {
+		.read = feed_input_zstream,
+		.data = &data,
+	};
+	struct obj_info *info = &obj_list[nr];
+
+	data.zstream = &zstream;
+	git_inflate_init(&zstream);
+
+	if (stream_loose_object(&in_stream, size, &info->oid))
+		die(_("failed to write object in stream"));
+
+	if (data.status != Z_STREAM_END)
+		die(_("inflate returned (%d)"), data.status);
+	git_inflate_end(&zstream);
+
+	if (strict) {
+		struct blob *blob = lookup_blob(the_repository, &info->oid);
+
+		if (!blob)
+			die(_("invalid blob object from stream"));
+		blob->object.flags |= FLAG_WRITTEN;
+	}
+	info->obj = NULL;
 }
 
 static int resolve_against_held(unsigned nr, const struct object_id *base,
@@ -359,10 +440,8 @@
 		oidread(&base_oid, fill(the_hash_algo->rawsz));
 		use(the_hash_algo->rawsz);
 		delta_data = get_data(delta_size);
-		if (dry_run || !delta_data) {
-			free(delta_data);
+		if (!delta_data)
 			return;
-		}
 		if (has_object_file(&base_oid))
 			; /* Ok we have this one */
 		else if (resolve_against_held(nr, &base_oid,
@@ -398,10 +477,8 @@
 			die("offset value out of bound for delta base object");
 
 		delta_data = get_data(delta_size);
-		if (dry_run || !delta_data) {
-			free(delta_data);
+		if (!delta_data)
 			return;
-		}
 		lo = 0;
 		hi = nr;
 		while (lo < hi) {
@@ -468,9 +545,14 @@
 	}
 
 	switch (type) {
+	case OBJ_BLOB:
+		if (!dry_run && size > big_file_threshold) {
+			stream_blob(size, nr);
+			return;
+		}
+		/* fallthrough */
 	case OBJ_COMMIT:
 	case OBJ_TREE:
-	case OBJ_BLOB:
 	case OBJ_TAG:
 		unpack_non_delta_entry(type, size, nr);
 		return;
diff --git a/builtin/worktree.c b/builtin/worktree.c
index cd62eef..c6710b2 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -1112,31 +1112,24 @@
 
 int cmd_worktree(int ac, const char **av, const char *prefix)
 {
+	parse_opt_subcommand_fn *fn = NULL;
 	struct option options[] = {
+		OPT_SUBCOMMAND("add", &fn, add),
+		OPT_SUBCOMMAND("prune", &fn, prune),
+		OPT_SUBCOMMAND("list", &fn, list),
+		OPT_SUBCOMMAND("lock", &fn, lock_worktree),
+		OPT_SUBCOMMAND("unlock", &fn, unlock_worktree),
+		OPT_SUBCOMMAND("move", &fn, move_worktree),
+		OPT_SUBCOMMAND("remove", &fn, remove_worktree),
+		OPT_SUBCOMMAND("repair", &fn, repair),
 		OPT_END()
 	};
 
 	git_config(git_worktree_config, NULL);
 
-	if (ac < 2)
-		usage_with_options(worktree_usage, options);
 	if (!prefix)
 		prefix = "";
-	if (!strcmp(av[1], "add"))
-		return add(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "prune"))
-		return prune(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "list"))
-		return list(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "lock"))
-		return lock_worktree(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "unlock"))
-		return unlock_worktree(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "move"))
-		return move_worktree(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "remove"))
-		return remove_worktree(ac - 1, av + 1, prefix);
-	if (!strcmp(av[1], "repair"))
-		return repair(ac - 1, av + 1, prefix);
-	usage_with_options(worktree_usage, options);
+
+	ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
+	return fn(ac, av, prefix);
 }
diff --git a/bulk-checkin.c b/bulk-checkin.c
index 98ec893..855b68e 100644
--- a/bulk-checkin.c
+++ b/bulk-checkin.c
@@ -340,6 +340,8 @@
 	 */
 	if (!bulk_fsync_objdir ||
 	    git_fsync(fd, FSYNC_WRITEOUT_ONLY) < 0) {
+		if (errno == ENOSYS)
+			warning(_("core.fsyncMethod = batch is unsupported on this platform"));
 		fsync_or_die(fd, filename);
 	}
 }
diff --git a/bundle-uri.c b/bundle-uri.c
new file mode 100644
index 0000000..4a8cc74
--- /dev/null
+++ b/bundle-uri.c
@@ -0,0 +1,168 @@
+#include "cache.h"
+#include "bundle-uri.h"
+#include "bundle.h"
+#include "object-store.h"
+#include "refs.h"
+#include "run-command.h"
+
+static int find_temp_filename(struct strbuf *name)
+{
+	int fd;
+	/*
+	 * Find a temporary filename that is available. This is briefly
+	 * racy, but unlikely to collide.
+	 */
+	fd = odb_mkstemp(name, "bundles/tmp_uri_XXXXXX");
+	if (fd < 0) {
+		warning(_("failed to create temporary file"));
+		return -1;
+	}
+
+	close(fd);
+	unlink(name->buf);
+	return 0;
+}
+
+static int download_https_uri_to_file(const char *file, const char *uri)
+{
+	int result = 0;
+	struct child_process cp = CHILD_PROCESS_INIT;
+	FILE *child_in = NULL, *child_out = NULL;
+	struct strbuf line = STRBUF_INIT;
+	int found_get = 0;
+
+	strvec_pushl(&cp.args, "git-remote-https", uri, NULL);
+	cp.in = -1;
+	cp.out = -1;
+
+	if (start_command(&cp))
+		return 1;
+
+	child_in = fdopen(cp.in, "w");
+	if (!child_in) {
+		result = 1;
+		goto cleanup;
+	}
+
+	child_out = fdopen(cp.out, "r");
+	if (!child_out) {
+		result = 1;
+		goto cleanup;
+	}
+
+	fprintf(child_in, "capabilities\n");
+	fflush(child_in);
+
+	while (!strbuf_getline(&line, child_out)) {
+		if (!line.len)
+			break;
+		if (!strcmp(line.buf, "get"))
+			found_get = 1;
+	}
+	strbuf_release(&line);
+
+	if (!found_get) {
+		result = error(_("insufficient capabilities"));
+		goto cleanup;
+	}
+
+	fprintf(child_in, "get %s %s\n\n", uri, file);
+
+cleanup:
+	if (child_in)
+		fclose(child_in);
+	if (finish_command(&cp))
+		return 1;
+	if (child_out)
+		fclose(child_out);
+	return result;
+}
+
+static int copy_uri_to_file(const char *filename, const char *uri)
+{
+	const char *out;
+
+	if (starts_with(uri, "https:") ||
+	    starts_with(uri, "http:"))
+		return download_https_uri_to_file(filename, uri);
+
+	if (skip_prefix(uri, "file://", &out))
+		uri = out;
+
+	/* Copy as a file */
+	return copy_file(filename, uri, 0);
+}
+
+static int unbundle_from_file(struct repository *r, const char *file)
+{
+	int result = 0;
+	int bundle_fd;
+	struct bundle_header header = BUNDLE_HEADER_INIT;
+	struct string_list_item *refname;
+	struct strbuf bundle_ref = STRBUF_INIT;
+	size_t bundle_prefix_len;
+
+	if ((bundle_fd = read_bundle_header(file, &header)) < 0)
+		return 1;
+
+	if ((result = unbundle(r, &header, bundle_fd, NULL)))
+		return 1;
+
+	/*
+	 * Convert all refs/heads/ from the bundle into refs/bundles/
+	 * in the local repository.
+	 */
+	strbuf_addstr(&bundle_ref, "refs/bundles/");
+	bundle_prefix_len = bundle_ref.len;
+
+	for_each_string_list_item(refname, &header.references) {
+		struct object_id *oid = refname->util;
+		struct object_id old_oid;
+		const char *branch_name;
+		int has_old;
+
+		if (!skip_prefix(refname->string, "refs/heads/", &branch_name))
+			continue;
+
+		strbuf_setlen(&bundle_ref, bundle_prefix_len);
+		strbuf_addstr(&bundle_ref, branch_name);
+
+		has_old = !read_ref(bundle_ref.buf, &old_oid);
+		update_ref("fetched bundle", bundle_ref.buf, oid,
+			   has_old ? &old_oid : NULL,
+			   REF_SKIP_OID_VERIFICATION,
+			   UPDATE_REFS_MSG_ON_ERR);
+	}
+
+	bundle_header_release(&header);
+	return result;
+}
+
+int fetch_bundle_uri(struct repository *r, const char *uri)
+{
+	int result = 0;
+	struct strbuf filename = STRBUF_INIT;
+
+	if ((result = find_temp_filename(&filename)))
+		goto cleanup;
+
+	if ((result = copy_uri_to_file(filename.buf, uri))) {
+		warning(_("failed to download bundle from URI '%s'"), uri);
+		goto cleanup;
+	}
+
+	if ((result = !is_bundle(filename.buf, 0))) {
+		warning(_("file at URI '%s' is not a bundle"), uri);
+		goto cleanup;
+	}
+
+	if ((result = unbundle_from_file(r, filename.buf))) {
+		warning(_("failed to unbundle bundle from URI '%s'"), uri);
+		goto cleanup;
+	}
+
+cleanup:
+	unlink(filename.buf);
+	strbuf_release(&filename);
+	return result;
+}
diff --git a/bundle-uri.h b/bundle-uri.h
new file mode 100644
index 0000000..8a152f1
--- /dev/null
+++ b/bundle-uri.h
@@ -0,0 +1,14 @@
+#ifndef BUNDLE_URI_H
+#define BUNDLE_URI_H
+
+struct repository;
+
+/**
+ * Fetch data from the given 'uri' and unbundle the bundle data found
+ * based on that information.
+ *
+ * Returns non-zero if no bundle information is found at the given 'uri'.
+ */
+int fetch_bundle_uri(struct repository *r, const char *uri);
+
+#endif
diff --git a/cache-tree.c b/cache-tree.c
index 56db0b5..c97111c 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -857,9 +857,7 @@
 	return 0;
 }
 
-static void verify_one_sparse(struct repository *r,
-			      struct index_state *istate,
-			      struct cache_tree *it,
+static void verify_one_sparse(struct index_state *istate,
 			      struct strbuf *path,
 			      int pos)
 {
@@ -910,7 +908,7 @@
 			return 1;
 
 		if (pos >= 0) {
-			verify_one_sparse(r, istate, it, path, pos);
+			verify_one_sparse(istate, path, pos);
 			return 0;
 		}
 
diff --git a/cache.h b/cache.h
index 33fc833..26ed03b 100644
--- a/cache.h
+++ b/cache.h
@@ -475,8 +475,7 @@
 
 /*
  * Values in this enum (except those outside the 3 bit range) are part
- * of pack file format. See Documentation/technical/pack-format.txt
- * for more information.
+ * of pack file format. See gitformat-pack(5) for more information.
  */
 enum object_type {
 	OBJ_BAD = -1,
@@ -1017,7 +1016,6 @@
  * commands that do not want replace references to be active.
  */
 extern int read_replace_refs;
-extern char *git_replace_ref_base;
 
 /*
  * These values are used to help identify parts of a repository to fsync.
@@ -1698,6 +1696,12 @@
 int split_ident_line(struct ident_split *, const char *, int);
 
 /*
+ * Given a commit or tag object buffer and the commit or tag headers, replaces
+ * the idents in the headers with their canonical versions using the mailmap mechanism.
+ */
+void apply_mailmap_to_header(struct strbuf *, const char **, struct string_list *);
+
+/*
  * Compare split idents for equality or strict ordering. Note that we
  * compare only the ident part of the line, ignoring any timestamp.
  *
diff --git a/ci/lib.sh b/ci/lib.sh
index f095519..1b0cc2b 100755
--- a/ci/lib.sh
+++ b/ci/lib.sh
@@ -276,6 +276,7 @@
 linux-leaks)
 	export SANITIZE=leak
 	export GIT_TEST_PASSING_SANITIZE_LEAK=true
+	export GIT_TEST_SANITIZE_LEAK_LOG=true
 	;;
 esac
 
diff --git a/color.c b/color.c
index 4f884c6..f05d8a8 100644
--- a/color.c
+++ b/color.c
@@ -415,7 +415,7 @@
 	return var;
 }
 
-int git_color_config(const char *var, const char *value, void *cb)
+int git_color_config(const char *var, const char *value, void *cb UNUSED)
 {
 	if (!strcmp(var, "color.ui")) {
 		git_use_color_default = git_config_colorbool(var, value);
diff --git a/command-list.txt b/command-list.txt
index 9bd6f3c..f96bdab 100644
--- a/command-list.txt
+++ b/command-list.txt
@@ -43,6 +43,15 @@
 # specified here, which can only have "guide" attribute and nothing
 # else.
 #
+# User-facing repository, command and file interfaces such as
+# documentation for the .gitmodules, .mailmap etc. files lives in man
+# sections 5 and 7. These entries can only have the "userinterfaces"
+# attribute and nothing else.
+#
+# Git's file formats and protocols, such as documentation for the
+# *.bundle format lives in man section 5. These entries can only have
+# the "developerinterfaces" attribute and nothing else.
+#
 ### command list (do not change this line)
 # command name                          category [category] [category]
 git-add                                 mainporcelain           worktree
@@ -192,24 +201,35 @@
 git-whatchanged                         ancillaryinterrogators          complete
 git-worktree                            mainporcelain
 git-write-tree                          plumbingmanipulators
-gitattributes                           guide
-gitcli                                  guide
+gitattributes                           userinterfaces
+gitcli                                  userinterfaces
 gitcore-tutorial                        guide
 gitcredentials                          guide
 gitcvs-migration                        guide
 gitdiffcore                             guide
 giteveryday                             guide
 gitfaq                                  guide
+gitformat-bundle                        developerinterfaces
+gitformat-chunk                         developerinterfaces
+gitformat-commit-graph                  developerinterfaces
+gitformat-index                         developerinterfaces
+gitformat-pack                          developerinterfaces
+gitformat-signature                     developerinterfaces
 gitglossary                             guide
-githooks                                guide
-gitignore                               guide
+githooks                                userinterfaces
+gitignore                               userinterfaces
 gitk                                    mainporcelain
-gitmailmap                              guide
-gitmodules                              guide
+gitmailmap                              userinterfaces
+gitmodules                              userinterfaces
 gitnamespaces                           guide
+gitprotocol-capabilities                developerinterfaces
+gitprotocol-common                      developerinterfaces
+gitprotocol-http                        developerinterfaces
+gitprotocol-pack                        developerinterfaces
+gitprotocol-v2                          developerinterfaces
 gitremote-helpers                       guide
-gitrepository-layout                    guide
-gitrevisions                            guide
+gitrepository-layout                    userinterfaces
+gitrevisions                            userinterfaces
 gitsubmodules                           guide
 gittutorial                             guide
 gittutorial-2                           guide
diff --git a/commit-graph.c b/commit-graph.c
index a487d49..06f7d9e 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -252,7 +252,8 @@
 	}
 	graph_map = xmmap(NULL, graph_size, PROT_READ, MAP_PRIVATE, fd, 0);
 	close(fd);
-	ret = parse_commit_graph(r, graph_map, graph_size);
+	prepare_repo_settings(r);
+	ret = parse_commit_graph(&r->settings, graph_map, graph_size);
 
 	if (ret)
 		ret->odb = odb;
@@ -321,7 +322,7 @@
 	return 0;
 }
 
-struct commit_graph *parse_commit_graph(struct repository *r,
+struct commit_graph *parse_commit_graph(struct repo_settings *s,
 					void *graph_map, size_t graph_size)
 {
 	const unsigned char *data;
@@ -359,8 +360,6 @@
 		return NULL;
 	}
 
-	prepare_repo_settings(r);
-
 	graph = alloc_commit_graph();
 
 	graph->hash_len = the_hash_algo->rawsz;
@@ -390,7 +389,7 @@
 	pair_chunk(cf, GRAPH_CHUNKID_EXTRAEDGES, &graph->chunk_extra_edges);
 	pair_chunk(cf, GRAPH_CHUNKID_BASE, &graph->chunk_base_graphs);
 
-	if (get_configured_generation_version(r) >= 2) {
+	if (s->commit_graph_generation_version >= 2) {
 		pair_chunk(cf, GRAPH_CHUNKID_GENERATION_DATA,
 			&graph->chunk_generation_data);
 		pair_chunk(cf, GRAPH_CHUNKID_GENERATION_DATA_OVERFLOW,
@@ -400,7 +399,7 @@
 			graph->read_generation_data = 1;
 	}
 
-	if (r->settings.commit_graph_read_changed_paths) {
+	if (s->commit_graph_read_changed_paths) {
 		pair_chunk(cf, GRAPH_CHUNKID_BLOOMINDEXES,
 			   &graph->chunk_bloom_indexes);
 		read_chunk(cf, GRAPH_CHUNKID_BLOOMDATA,
@@ -902,7 +901,7 @@
 	struct commit *commit;
 	uint32_t pos;
 
-	if (!repo->objects->commit_graph)
+	if (!prepare_commit_graph(repo))
 		return NULL;
 	if (!search_commit_pos_in_graph(id, repo->objects->commit_graph, &pos))
 		return NULL;
@@ -1640,9 +1639,9 @@
 	struct progress *progress;
 };
 
-static int add_ref_to_set(const char *refname,
+static int add_ref_to_set(const char *refname UNUSED,
 			  const struct object_id *oid,
-			  int flags, void *cb_data)
+			  int flags UNUSED, void *cb_data)
 {
 	struct object_id peeled;
 	struct refs_cb_data *data = (struct refs_cb_data *)cb_data;
diff --git a/commit-graph.h b/commit-graph.h
index f23b9e9..37faee6 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -108,7 +108,12 @@
 						 struct object_directory *odb);
 struct commit_graph *read_commit_graph_one(struct repository *r,
 					   struct object_directory *odb);
-struct commit_graph *parse_commit_graph(struct repository *r,
+
+/*
+ * Callers should initialize the repo_settings with prepare_repo_settings()
+ * prior to calling parse_commit_graph().
+ */
+struct commit_graph *parse_commit_graph(struct repo_settings *s,
 					void *graph_map, size_t graph_size);
 
 /*
diff --git a/commit.c b/commit.c
index 1fb1b2e..89b8efc 100644
--- a/commit.c
+++ b/commit.c
@@ -642,10 +642,11 @@
 	return commit_list_insert(item, pp);
 }
 
-static int commit_list_compare_by_date(const void *a, const void *b)
+static int commit_list_compare_by_date(const struct commit_list *a,
+				       const struct commit_list *b)
 {
-	timestamp_t a_date = ((const struct commit_list *)a)->item->date;
-	timestamp_t b_date = ((const struct commit_list *)b)->item->date;
+	timestamp_t a_date = a->item->date;
+	timestamp_t b_date = b->item->date;
 	if (a_date < b_date)
 		return 1;
 	if (a_date > b_date)
@@ -653,20 +654,11 @@
 	return 0;
 }
 
-static void *commit_list_get_next(const void *a)
-{
-	return ((const struct commit_list *)a)->next;
-}
-
-static void commit_list_set_next(void *a, void *next)
-{
-	((struct commit_list *)a)->next = next;
-}
+DEFINE_LIST_SORT(static, commit_list_sort, struct commit_list, next);
 
 void commit_list_sort_by_date(struct commit_list **list)
 {
-	*list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
-				commit_list_compare_by_date);
+	commit_list_sort(list, commit_list_compare_by_date);
 }
 
 struct commit *pop_most_recent_commit(struct commit_list **list,
@@ -959,8 +951,9 @@
 }
 
 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
-				  const char *ident, timestamp_t timestamp,
-				  int tz, const char *message, void *cbdata)
+				  const char *ident UNUSED,
+				  timestamp_t timestamp UNUSED, int tz UNUSED,
+				  const char *message UNUSED, void *cbdata)
 {
 	struct rev_collect *revs = cbdata;
 
diff --git a/compat/disk.h b/compat/disk.h
new file mode 100644
index 0000000..50a32e3
--- /dev/null
+++ b/compat/disk.h
@@ -0,0 +1,56 @@
+#ifndef COMPAT_DISK_H
+#define COMPAT_DISK_H
+
+#include "git-compat-util.h"
+
+static int get_disk_info(struct strbuf *out)
+{
+	struct strbuf buf = STRBUF_INIT;
+	int res = 0;
+
+#ifdef GIT_WINDOWS_NATIVE
+	char volume_name[MAX_PATH], fs_name[MAX_PATH];
+	DWORD serial_number, component_length, flags;
+	ULARGE_INTEGER avail2caller, total, avail;
+
+	strbuf_realpath(&buf, ".", 1);
+	if (!GetDiskFreeSpaceExA(buf.buf, &avail2caller, &total, &avail)) {
+		error(_("could not determine free disk size for '%s'"),
+		      buf.buf);
+		res = -1;
+		goto cleanup;
+	}
+
+	strbuf_setlen(&buf, offset_1st_component(buf.buf));
+	if (!GetVolumeInformationA(buf.buf, volume_name, sizeof(volume_name),
+				   &serial_number, &component_length, &flags,
+				   fs_name, sizeof(fs_name))) {
+		error(_("could not get info for '%s'"), buf.buf);
+		res = -1;
+		goto cleanup;
+	}
+	strbuf_addf(out, "Available space on '%s': ", buf.buf);
+	strbuf_humanise_bytes(out, avail2caller.QuadPart);
+	strbuf_addch(out, '\n');
+#else
+	struct statvfs stat;
+
+	strbuf_realpath(&buf, ".", 1);
+	if (statvfs(buf.buf, &stat) < 0) {
+		error_errno(_("could not determine free disk size for '%s'"),
+			    buf.buf);
+		res = -1;
+		goto cleanup;
+	}
+
+	strbuf_addf(out, "Available space on '%s': ", buf.buf);
+	strbuf_humanise_bytes(out, (off_t)stat.f_bsize * (off_t)stat.f_bavail);
+	strbuf_addf(out, " (mount flags 0x%lx)\n", stat.f_flag);
+#endif
+
+cleanup:
+	strbuf_release(&buf);
+	return res;
+}
+
+#endif /* COMPAT_DISK_H */
diff --git a/compat/fsmonitor/fsm-settings-win32.c b/compat/fsmonitor/fsm-settings-win32.c
index 9076557..e5ec5b0 100644
--- a/compat/fsmonitor/fsm-settings-win32.c
+++ b/compat/fsmonitor/fsm-settings-win32.c
@@ -25,6 +25,59 @@
 }
 
 /*
+ * Check if monitoring remote working directories is allowed.
+ *
+ * By default, monitoring remote working directories is
+ * disabled.  Users may override this behavior in enviroments where
+ * they have proper support.
+ */
+static int check_config_allowremote(struct repository *r)
+{
+	int allow;
+
+	if (!repo_config_get_bool(r, "fsmonitor.allowremote", &allow))
+		return allow;
+
+	return -1; /* fsmonitor.allowremote not set */
+}
+
+/*
+ * Check remote working directory protocol.
+ *
+ * Error if client machine cannot get remote protocol information.
+ */
+static int check_remote_protocol(wchar_t *wpath)
+{
+	HANDLE h;
+	FILE_REMOTE_PROTOCOL_INFO proto_info;
+
+	h = CreateFileW(wpath, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING,
+			FILE_FLAG_BACKUP_SEMANTICS, NULL);
+
+	if (h == INVALID_HANDLE_VALUE) {
+		error(_("[GLE %ld] unable to open for read '%ls'"),
+		      GetLastError(), wpath);
+		return -1;
+	}
+
+	if (!GetFileInformationByHandleEx(h, FileRemoteProtocolInfo,
+		&proto_info, sizeof(proto_info))) {
+		error(_("[GLE %ld] unable to get protocol information for '%ls'"),
+		      GetLastError(), wpath);
+		CloseHandle(h);
+		return -1;
+	}
+
+	CloseHandle(h);
+
+	trace_printf_key(&trace_fsmonitor,
+				"check_remote_protocol('%ls') remote protocol %#8.8lx",
+				wpath, proto_info.Protocol);
+
+	return 0;
+}
+
+/*
  * Remote working directories are problematic for FSMonitor.
  *
  * The underlying file system on the server machine and/or the remote
@@ -76,6 +129,7 @@
  */
 static enum fsmonitor_reason check_remote(struct repository *r)
 {
+	int ret;
 	wchar_t wpath[MAX_PATH];
 	wchar_t wfullpath[MAX_PATH];
 	size_t wlen;
@@ -115,6 +169,20 @@
 		trace_printf_key(&trace_fsmonitor,
 				 "check_remote('%s') true",
 				 r->worktree);
+
+		ret = check_remote_protocol(wfullpath);
+		if (ret < 0)
+			return FSMONITOR_REASON_ERROR;
+
+		switch (check_config_allowremote(r)) {
+		case 0: /* config overrides and disables */
+			return FSMONITOR_REASON_REMOTE;
+		case 1: /* config overrides and enables */
+			return FSMONITOR_REASON_OK;
+		default:
+			break; /* config has no opinion */
+		}
+
 		return FSMONITOR_REASON_REMOTE;
 	}
 
diff --git a/compat/nonblock.c b/compat/nonblock.c
new file mode 100644
index 0000000..9694ebd
--- /dev/null
+++ b/compat/nonblock.c
@@ -0,0 +1,50 @@
+#include "git-compat-util.h"
+#include "nonblock.h"
+
+#ifdef O_NONBLOCK
+
+int enable_pipe_nonblock(int fd)
+{
+	int flags = fcntl(fd, F_GETFL);
+	if (flags < 0)
+		return -1;
+	flags |= O_NONBLOCK;
+	return fcntl(fd, F_SETFL, flags);
+}
+
+#elif defined(GIT_WINDOWS_NATIVE)
+
+#include "win32.h"
+
+int enable_pipe_nonblock(int fd)
+{
+	HANDLE h = (HANDLE)_get_osfhandle(fd);
+	DWORD mode;
+	DWORD type = GetFileType(h);
+	if (type == FILE_TYPE_UNKNOWN && GetLastError() != NO_ERROR) {
+		errno = EBADF;
+		return -1;
+	}
+	if (type != FILE_TYPE_PIPE)
+		BUG("unsupported file type: %lu", type);
+	if (!GetNamedPipeHandleState(h, &mode, NULL, NULL, NULL, NULL, 0)) {
+		errno = err_win_to_posix(GetLastError());
+		return -1;
+	}
+	mode |= PIPE_NOWAIT;
+	if (!SetNamedPipeHandleState(h, &mode, NULL, NULL)) {
+		errno = err_win_to_posix(GetLastError());
+		return -1;
+	}
+	return 0;
+}
+
+#else
+
+int enable_pipe_nonblock(int fd)
+{
+	errno = ENOSYS;
+	return -1;
+}
+
+#endif
diff --git a/compat/nonblock.h b/compat/nonblock.h
new file mode 100644
index 0000000..af1a331
--- /dev/null
+++ b/compat/nonblock.h
@@ -0,0 +1,9 @@
+#ifndef COMPAT_NONBLOCK_H
+#define COMPAT_NONBLOCK_H
+
+/*
+ * Enable non-blocking I/O for the pipe specified by the passed-in descriptor.
+ */
+int enable_pipe_nonblock(int fd);
+
+#endif
diff --git a/compat/terminal.c b/compat/terminal.c
index 7db330c..ea490a7 100644
--- a/compat/terminal.c
+++ b/compat/terminal.c
@@ -477,7 +477,7 @@
 	char sequence[FLEX_ARRAY];
 };
 
-static int sequence_entry_cmp(const void *hashmap_cmp_fn_data,
+static int sequence_entry_cmp(const void *hashmap_cmp_fn_data UNUSED,
 			      const struct escape_sequence_entry *e1,
 			      const struct escape_sequence_entry *e2,
 			      const void *keydata)
diff --git a/config.c b/config.c
index 9b0e9c9..cbb5a3b 100644
--- a/config.c
+++ b/config.c
@@ -81,6 +81,17 @@
 static int pack_compression_seen;
 static int zlib_compression_seen;
 
+/*
+ * Config that comes from trusted scopes, namely:
+ * - CONFIG_SCOPE_SYSTEM (e.g. /etc/gitconfig)
+ * - CONFIG_SCOPE_GLOBAL (e.g. $HOME/.gitconfig, $XDG_CONFIG_HOME/git)
+ * - CONFIG_SCOPE_COMMAND (e.g. "-c" option, environment variables)
+ *
+ * This is declared here for code cleanliness, but unlike the other
+ * static variables, this does not hold config parser state.
+ */
+static struct config_set protected_config;
+
 static int config_file_fgetc(struct config_source *conf)
 {
 	return getc_unlocked(conf->u.file);
@@ -351,7 +362,8 @@
 	current_parsing_scope = store_scope;
 }
 
-static int forbid_remote_url(const char *var, const char *value, void *data)
+static int forbid_remote_url(const char *var, const char *value UNUSED,
+			     void *data UNUSED)
 {
 	const char *remote_name;
 	size_t remote_name_len;
@@ -1968,6 +1980,8 @@
 	int ret = -1;
 	FILE *f;
 
+	if (!filename)
+		BUG("filename cannot be NULL");
 	f = fopen_or_warn(filename, "r");
 	if (f) {
 		ret = do_config_from_file(fn, CONFIG_ORIGIN_FILE, filename,
@@ -2324,10 +2338,10 @@
 	return 0;
 }
 
-static int config_set_element_cmp(const void *unused_cmp_data,
+static int config_set_element_cmp(const void *cmp_data UNUSED,
 				  const struct hashmap_entry *eptr,
 				  const struct hashmap_entry *entry_or_key,
-				  const void *unused_keydata)
+				  const void *keydata UNUSED)
 {
 	const struct config_set_element *e1, *e2;
 
@@ -2378,6 +2392,11 @@
 	return git_config_from_file(config_set_callback, filename, cs);
 }
 
+int git_configset_add_parameters(struct config_set *cs)
+{
+	return git_config_from_parameters(config_set_callback, cs);
+}
+
 int git_configset_get_value(struct config_set *cs, const char *key, const char **value)
 {
 	const struct string_list *values = NULL;
@@ -2619,6 +2638,36 @@
 	return ret;
 }
 
+/* Read values into protected_config. */
+static void read_protected_config(void)
+{
+	char *xdg_config = NULL, *user_config = NULL, *system_config = NULL;
+
+	git_configset_init(&protected_config);
+
+	system_config = git_system_config();
+	git_global_config(&user_config, &xdg_config);
+
+	if (system_config)
+		git_configset_add_file(&protected_config, system_config);
+	if (xdg_config)
+		git_configset_add_file(&protected_config, xdg_config);
+	if (user_config)
+		git_configset_add_file(&protected_config, user_config);
+	git_configset_add_parameters(&protected_config);
+
+	free(system_config);
+	free(xdg_config);
+	free(user_config);
+}
+
+void git_protected_config(config_fn_t fn, void *data)
+{
+	if (!protected_config.hash_initialized)
+		read_protected_config();
+	configset_iter(&protected_config, fn, data);
+}
+
 /* Functions used historically to read configuration from 'the_repository' */
 void git_config(config_fn_t fn, void *data)
 {
diff --git a/config.h b/config.h
index 7654f61..ca994d7 100644
--- a/config.h
+++ b/config.h
@@ -447,6 +447,15 @@
 int git_configset_add_file(struct config_set *cs, const char *filename);
 
 /**
+ * Parses command line options and environment variables, and adds the
+ * variable-value pairs to the `config_set`. Returns 0 on success, or -1
+ * if there is an error in parsing. The caller decides whether to free
+ * the incomplete configset or continue using it when the function
+ * returns -1.
+ */
+int git_configset_add_parameters(struct config_set *cs);
+
+/**
  * Finds and returns the value list, sorted in order of increasing priority
  * for the configuration variable `key` and config set `cs`. When the
  * configuration variable `key` is not found, returns NULL. The caller
@@ -505,6 +514,13 @@
 int repo_config_get_pathname(struct repository *repo,
 			     const char *key, const char **dest);
 
+/*
+ * Functions for reading protected config. By definition, protected
+ * config ignores repository config, so these do not take a `struct
+ * repository` parameter.
+ */
+void git_protected_config(config_fn_t fn, void *data);
+
 /**
  * Querying For Specific Variables
  * -------------------------------
diff --git a/configure.ac b/configure.ac
index 7dcd048..38ff866 100644
--- a/configure.ac
+++ b/configure.ac
@@ -237,9 +237,6 @@
 # tests.  These tests take up a significant amount of the total test time
 # but are not needed unless you plan to talk to SVN repos.
 #
-# Define PPC_SHA1 environment variable when running make to make use of
-# a bundled SHA1 routine optimized for PowerPC.
-#
 # Define NO_OPENSSL environment variable if you do not have OpenSSL.
 #
 # Define OPENSSLDIR=/foo/bar if your openssl header and library files are in
diff --git a/contrib/coccinelle/array.cocci b/contrib/coccinelle/array.cocci
index 9a4f00c..aa75937 100644
--- a/contrib/coccinelle/array.cocci
+++ b/contrib/coccinelle/array.cocci
@@ -1,60 +1,58 @@
 @@
-expression dst, src, n, E;
-@@
-  memcpy(dst, src, n * sizeof(
-- E[...]
-+ *(E)
-  ))
-
-@@
 type T;
-T *ptr;
-T[] arr;
-expression E, n;
+T *dst_ptr;
+T *src_ptr;
+expression n;
 @@
-(
-  memcpy(ptr, E,
-- n * sizeof(*(ptr))
-+ n * sizeof(T)
-  )
-|
-  memcpy(arr, E,
-- n * sizeof(*(arr))
-+ n * sizeof(T)
-  )
-|
-  memcpy(E, ptr,
-- n * sizeof(*(ptr))
-+ n * sizeof(T)
-  )
-|
-  memcpy(E, arr,
-- n * sizeof(*(arr))
-+ n * sizeof(T)
-  )
-)
+- memcpy(dst_ptr, src_ptr, (n) * \( sizeof(T)
+-                                \| sizeof(*(dst_ptr))
+-                                \| sizeof(*(src_ptr))
+-                                \| sizeof(dst_ptr[...])
+-                                \| sizeof(src_ptr[...])
+-                                \) )
++ COPY_ARRAY(dst_ptr, src_ptr, n)
 
 @@
 type T;
 T *dst_ptr;
+T[] src_arr;
+expression n;
+@@
+- memcpy(dst_ptr, src_arr, (n) * \( sizeof(T)
+-                                \| sizeof(*(dst_ptr))
+-                                \| sizeof(*(src_arr))
+-                                \| sizeof(dst_ptr[...])
+-                                \| sizeof(src_arr[...])
+-                                \) )
++ COPY_ARRAY(dst_ptr, src_arr, n)
+
+@@
+type T;
+T[] dst_arr;
 T *src_ptr;
+expression n;
+@@
+- memcpy(dst_arr, src_ptr, (n) * \( sizeof(T)
+-                                \| sizeof(*(dst_arr))
+-                                \| sizeof(*(src_ptr))
+-                                \| sizeof(dst_arr[...])
+-                                \| sizeof(src_ptr[...])
+-                                \) )
++ COPY_ARRAY(dst_arr, src_ptr, n)
+
+@@
+type T;
 T[] dst_arr;
 T[] src_arr;
 expression n;
 @@
-(
-- memcpy(dst_ptr, src_ptr, (n) * sizeof(T))
-+ COPY_ARRAY(dst_ptr, src_ptr, n)
-|
-- memcpy(dst_ptr, src_arr, (n) * sizeof(T))
-+ COPY_ARRAY(dst_ptr, src_arr, n)
-|
-- memcpy(dst_arr, src_ptr, (n) * sizeof(T))
-+ COPY_ARRAY(dst_arr, src_ptr, n)
-|
-- memcpy(dst_arr, src_arr, (n) * sizeof(T))
+- memcpy(dst_arr, src_arr, (n) * \( sizeof(T)
+-                                \| sizeof(*(dst_arr))
+-                                \| sizeof(*(src_arr))
+-                                \| sizeof(dst_arr[...])
+-                                \| sizeof(src_arr[...])
+-                                \) )
 + COPY_ARRAY(dst_arr, src_arr, n)
-)
 
 @@
 type T;
diff --git a/contrib/coccinelle/tests/free.c b/contrib/coccinelle/tests/free.c
new file mode 100644
index 0000000..96d4abc
--- /dev/null
+++ b/contrib/coccinelle/tests/free.c
@@ -0,0 +1,11 @@
+int use_FREE_AND_NULL(int *v)
+{
+	free(*v);
+	*v = NULL;
+}
+
+int need_no_if(int *v)
+{
+	if (v)
+		free(v);
+}
diff --git a/contrib/coccinelle/tests/free.res b/contrib/coccinelle/tests/free.res
new file mode 100644
index 0000000..f90fd9f
--- /dev/null
+++ b/contrib/coccinelle/tests/free.res
@@ -0,0 +1,9 @@
+int use_FREE_AND_NULL(int *v)
+{
+	FREE_AND_NULL(*v);
+}
+
+int need_no_if(int *v)
+{
+	free(v);
+}
diff --git a/contrib/coccinelle/tests/unused.c b/contrib/coccinelle/tests/unused.c
new file mode 100644
index 0000000..8294d73
--- /dev/null
+++ b/contrib/coccinelle/tests/unused.c
@@ -0,0 +1,82 @@
+void test_strbuf(void)
+{
+	struct strbuf sb1 = STRBUF_INIT;
+	struct strbuf sb2 = STRBUF_INIT;
+	struct strbuf sb3 = STRBUF_INIT;
+	struct strbuf sb4 = STRBUF_INIT;
+	struct strbuf sb5;
+	struct strbuf sb6 = { 0 };
+	struct strbuf sb7 = STRBUF_INIT;
+	struct strbuf sb8 = STRBUF_INIT;
+	struct strbuf *sp1;
+	struct strbuf *sp2;
+	struct strbuf *sp3;
+	struct strbuf *sp4 = xmalloc(sizeof(struct strbuf));
+	struct strbuf *sp5 = xmalloc(sizeof(struct strbuf));
+	struct strbuf *sp6 = xmalloc(sizeof(struct strbuf));
+	struct strbuf *sp7;
+
+	strbuf_init(&sb5, 0);
+	strbuf_init(sp1, 0);
+	strbuf_init(sp2, 0);
+	strbuf_init(sp3, 0);
+	strbuf_init(sp4, 0);
+	strbuf_init(sp5, 0);
+	strbuf_init(sp6, 0);
+	strbuf_init(sp7, 0);
+	sp7 = xmalloc(sizeof(struct strbuf));
+
+	use_before(&sb3);
+	use_as_str("%s", sb7.buf);
+	use_as_str("%s", sp1->buf);
+	use_as_str("%s", sp6->buf);
+	pass_pp(&sp3);
+
+	strbuf_release(&sb1);
+	strbuf_reset(&sb2);
+	strbuf_release(&sb3);
+	strbuf_release(&sb4);
+	strbuf_release(&sb5);
+	strbuf_release(&sb6);
+	strbuf_release(&sb7);
+	strbuf_release(sp1);
+	strbuf_release(sp2);
+	strbuf_release(sp3);
+	strbuf_release(sp4);
+	strbuf_release(sp5);
+	strbuf_release(sp6);
+	strbuf_release(sp7);
+
+	use_after(&sb4);
+
+	if (when_strict())
+		return;
+	strbuf_release(&sb8);
+}
+
+void test_other(void)
+{
+	struct string_list l = STRING_LIST_INIT_DUP;
+	struct strbuf sb = STRBUF_INIT;
+
+	string_list_clear(&l, 0);
+	string_list_clear(&sb, 0);
+}
+
+void test_worktrees(void)
+{
+	struct worktree **w1 = get_worktrees();
+	struct worktree **w2 = get_worktrees();
+	struct worktree **w3;
+	struct worktree **w4;
+
+	w3 = get_worktrees();
+	w4 = get_worktrees();
+
+	use_it(w4);
+
+	free_worktrees(w1);
+	free_worktrees(w2);
+	free_worktrees(w3);
+	free_worktrees(w4);
+}
diff --git a/contrib/coccinelle/tests/unused.res b/contrib/coccinelle/tests/unused.res
new file mode 100644
index 0000000..6d3e745
--- /dev/null
+++ b/contrib/coccinelle/tests/unused.res
@@ -0,0 +1,45 @@
+void test_strbuf(void)
+{
+	struct strbuf sb3 = STRBUF_INIT;
+	struct strbuf sb4 = STRBUF_INIT;
+	struct strbuf sb7 = STRBUF_INIT;
+	struct strbuf *sp1;
+	struct strbuf *sp3;
+	struct strbuf *sp6 = xmalloc(sizeof(struct strbuf));
+	strbuf_init(sp1, 0);
+	strbuf_init(sp3, 0);
+	strbuf_init(sp6, 0);
+
+	use_before(&sb3);
+	use_as_str("%s", sb7.buf);
+	use_as_str("%s", sp1->buf);
+	use_as_str("%s", sp6->buf);
+	pass_pp(&sp3);
+
+	strbuf_release(&sb3);
+	strbuf_release(&sb4);
+	strbuf_release(&sb7);
+	strbuf_release(sp1);
+	strbuf_release(sp3);
+	strbuf_release(sp6);
+
+	use_after(&sb4);
+
+	if (when_strict())
+		return;
+}
+
+void test_other(void)
+{
+}
+
+void test_worktrees(void)
+{
+	struct worktree **w4;
+
+	w4 = get_worktrees();
+
+	use_it(w4);
+
+	free_worktrees(w4);
+}
diff --git a/contrib/coccinelle/unused.cocci b/contrib/coccinelle/unused.cocci
new file mode 100644
index 0000000..d84046f
--- /dev/null
+++ b/contrib/coccinelle/unused.cocci
@@ -0,0 +1,43 @@
+// This rule finds sequences of "unused" declerations and uses of a
+// variable, where "unused" is defined to include only calling the
+// equivalent of alloc, init & free functions on the variable.
+@@
+type T;
+identifier I;
+// STRBUF_INIT, but also e.g. STRING_LIST_INIT_DUP (so no anchoring)
+constant INIT_MACRO =~ "_INIT";
+identifier MALLOC1 =~ "^x?[mc]alloc$";
+identifier INIT_ASSIGN1 =~ "^get_worktrees$";
+identifier INIT_CALL1 =~ "^[a-z_]*_init$";
+identifier REL1 =~ "^[a-z_]*_(release|reset|clear|free)$";
+identifier REL2 =~ "^(release|clear|free)_[a-z_]*$";
+@@
+
+(
+- T I;
+|
+- T I = { 0 };
+|
+- T I = INIT_MACRO;
+|
+- T I = MALLOC1(...);
+|
+- T I = INIT_ASSIGN1(...);
+)
+
+<... when != \( I \| &I \)
+(
+- \( INIT_CALL1 \)( \( I \| &I \), ...);
+|
+- I = \( INIT_ASSIGN1 \)(...);
+|
+- I = MALLOC1(...);
+)
+...>
+
+(
+- \( REL1 \| REL2 \)( \( I \| &I \), ...);
+|
+- \( REL1 \| REL2 \)( \( &I \| I \) );
+)
+  ... when != \( I \| &I \)
diff --git a/contrib/completion/git-prompt.sh b/contrib/completion/git-prompt.sh
index 1435548..57972c2 100644
--- a/contrib/completion/git-prompt.sh
+++ b/contrib/completion/git-prompt.sh
@@ -84,6 +84,10 @@
 # single '?' character by setting GIT_PS1_COMPRESSSPARSESTATE, or omitted
 # by setting GIT_PS1_OMITSPARSESTATE.
 #
+# If you would like to see a notification on the prompt when there are
+# unresolved conflicts, set GIT_PS1_SHOWCONFLICTSTATE to "yes". The
+# prompt will include "|CONFLICT".
+#
 # If you would like to see more information about the identity of
 # commits checked out as a detached HEAD, set GIT_PS1_DESCRIBE_STYLE
 # to one of these values:
@@ -508,6 +512,12 @@
 		r="$r $step/$total"
 	fi
 
+	local conflict="" # state indicator for unresolved conflicts
+	if [[ "${GIT_PS1_SHOWCONFLICTSTATE}" == "yes" ]] &&
+	   [[ $(git ls-files --unmerged 2>/dev/null) ]]; then
+		conflict="|CONFLICT"
+	fi
+
 	local w=""
 	local i=""
 	local s=""
@@ -572,7 +582,7 @@
 	fi
 
 	local f="$h$w$i$s$u$p"
-	local gitstring="$c$b${f:+$z$f}${sparse}$r${upstream}"
+	local gitstring="$c$b${f:+$z$f}${sparse}$r${upstream}${conflict}"
 
 	if [ $pcmode = yes ]; then
 		if [ "${__git_printf_supports_v-}" != yes ]; then
diff --git a/contrib/credential/netrc/t-git-credential-netrc.sh b/contrib/credential/netrc/t-git-credential-netrc.sh
index 07227d0..bf27773 100755
--- a/contrib/credential/netrc/t-git-credential-netrc.sh
+++ b/contrib/credential/netrc/t-git-credential-netrc.sh
@@ -3,16 +3,9 @@
 	cd ../../../t
 	test_description='git-credential-netrc'
 	. ./test-lib.sh
+	. "$TEST_DIRECTORY"/lib-perl.sh
 
-	if ! test_have_prereq PERL; then
-		skip_all='skipping perl interface tests, perl not available'
-		test_done
-	fi
-
-	perl -MTest::More -e 0 2>/dev/null || {
-		skip_all="Perl Test::More unavailable, skipping test"
-		test_done
-	}
+	skip_all_if_no_Test_More
 
 	# set up test repository
 
@@ -20,13 +13,10 @@
 		'set up test repository' \
 		'git config --add gpg.program test.git-config-gpg'
 
-	# The external test will outputs its own plan
-	test_external_has_tap=1
-
 	export PERL5LIB="$GITPERLLIB"
-	test_external \
-		'git-credential-netrc' \
+	test_expect_success 'git-credential-netrc' '
 		perl "$GIT_BUILD_DIR"/contrib/credential/netrc/test.pl
+	'
 
 	test_done
 )
diff --git a/contrib/scalar/README.md b/contrib/scalar/README.md
deleted file mode 100644
index 634b577..0000000
--- a/contrib/scalar/README.md
+++ /dev/null
@@ -1,82 +0,0 @@
-# Scalar - an opinionated repository management tool
-
-Scalar is an add-on to Git that helps users take advantage of advanced
-performance features in Git. Originally implemented in C# using .NET Core,
-based on the learnings from the VFS for Git project, most of the techniques
-developed by the Scalar project have been integrated into core Git already:
-
-* partial clone,
-* commit graphs,
-* multi-pack index,
-* sparse checkout (cone mode),
-* scheduled background maintenance,
-* etc
-
-This directory contains the remaining parts of Scalar that are not (yet) in
-core Git.
-
-## Roadmap
-
-The idea is to populate this directory via incremental patch series and
-eventually move to a top-level directory next to `gitk-git/` and to `git-gui/`. The
-current plan involves the following patch series:
-
-- `scalar-the-beginning`: The initial patch series which sets up
-  `contrib/scalar/` and populates it with a minimal `scalar` command that
-  demonstrates the fundamental ideas.
-
-- `scalar-c-and-C`: The `scalar` command learns about two options that can be
-  specified before the command, `-c <key>=<value>` and `-C <directory>`.
-
-- `scalar-diagnose`: The `scalar` command is taught the `diagnose` subcommand.
-
-- `scalar-and-builtin-fsmonitor`: The built-in FSMonitor is enabled in `scalar
-  register` and in `scalar clone`, for an enormous performance boost when
-  working in large worktrees. This patch series necessarily depends on Jeff
-  Hostetler's FSMonitor patch series to be integrated into Git.
-
-- `scalar-gentler-config-locking`: Scalar enlistments are registered in the
-  user's Git config. This usually does not represent any problem because it is
-  rare for a user to register an enlistment. However, in Scalar's functional
-  tests, Scalar enlistments are created galore, and in parallel, which can lead
-  to lock contention. This patch series works around that problem by re-trying
-  to lock the config file in a gentle fashion.
-
-- `scalar-extra-docs`: Add some extensive documentation that has been written
-  in the original Scalar project (all subject to discussion, of course).
-
-- `optionally-install-scalar`: Now that Scalar is feature (and documentation)
-  complete and is verified in CI builds, let's offer to install it.
-
-- `move-scalar-to-toplevel`: Now that Scalar is complete, let's move it next to
-  `gitk-git/` and to `git-gui/`, making it a top-level command.
-
-The following two patch series exist in Microsoft's fork of Git and are
-publicly available. There is no current plan to upstream them, not because I
-want to withhold these patches, but because I don't think the Git community is
-interested in these patches.
-
-There are some interesting ideas there, but the implementation is too specific
-to Azure Repos and/or VFS for Git to be of much help in general (and also: my
-colleagues tried to upstream some patches already and the enthusiasm for
-integrating things related to Azure Repos and VFS for Git can be summarized in
-very, very few words).
-
-These still exist mainly because the GVFS protocol is what Azure Repos has
-instead of partial clone, while Git is focused on improving partial clone:
-
-- `scalar-with-gvfs`: The primary purpose of this patch series is to support
-  existing Scalar users whose repositories are hosted in Azure Repos (which
-  does not support Git's partial clones, but supports its predecessor, the GVFS
-  protocol, which is used by Scalar to emulate the partial clone).
-
-  Since the GVFS protocol will never be supported by core Git, this patch
-  series will remain in Microsoft's fork of Git.
-
-- `run-scalar-functional-tests`: The Scalar project developed a quite
-  comprehensive set of integration tests (or, "Functional Tests"). They are the
-  sole remaining part of the original C#-based Scalar project, and this patch
-  adds a GitHub workflow that runs them all.
-
-  Since the tests partially depend on features that are only provided in the
-  `scalar-with-gvfs` patch series, this patch cannot be upstreamed.
diff --git a/contrib/scalar/scalar.c b/contrib/scalar/scalar.c
index 2817691..642d161 100644
--- a/contrib/scalar/scalar.c
+++ b/contrib/scalar/scalar.c
@@ -7,27 +7,13 @@
 #include "parse-options.h"
 #include "config.h"
 #include "run-command.h"
+#include "simple-ipc.h"
+#include "fsmonitor-ipc.h"
+#include "fsmonitor-settings.h"
 #include "refs.h"
 #include "dir.h"
 #include "packfile.h"
 #include "help.h"
-#include "archive.h"
-#include "object-store.h"
-
-/*
- * Remove the deepest subdirectory in the provided path string. Path must not
- * include a trailing path separator. Returns 1 if parent directory found,
- * otherwise 0.
- */
-static int strbuf_parent_directory(struct strbuf *buf)
-{
-	size_t len = buf->len;
-	size_t offset = offset_1st_component(buf->buf);
-	char *path_sep = find_last_dir_sep(buf->buf + offset);
-	strbuf_setlen(buf, path_sep ? path_sep - buf->buf : offset);
-
-	return buf->len < len;
-}
 
 static void setup_enlistment_directory(int argc, const char **argv,
 				       const char * const *usagestr,
@@ -35,8 +21,8 @@
 				       struct strbuf *enlistment_root)
 {
 	struct strbuf path = STRBUF_INIT;
-	char *root;
-	int enlistment_found = 0;
+	int enlistment_is_repo_parent = 0;
+	size_t len;
 
 	if (startup_info->have_repository)
 		BUG("gitdir already set up?!?");
@@ -49,51 +35,36 @@
 		strbuf_add_absolute_path(&path, argv[0]);
 		if (!is_directory(path.buf))
 			die(_("'%s' does not exist"), path.buf);
+		if (chdir(path.buf) < 0)
+			die_errno(_("could not switch to '%s'"), path.buf);
 	} else if (strbuf_getcwd(&path) < 0)
 		die(_("need a working directory"));
 
 	strbuf_trim_trailing_dir_sep(&path);
-	do {
-		const size_t len = path.len;
 
-		/* check if currently in enlistment root with src/ workdir */
-		strbuf_addstr(&path, "/src");
-		if (is_nonbare_repository_dir(&path)) {
-			if (enlistment_root)
-				strbuf_add(enlistment_root, path.buf, len);
+	/* check if currently in enlistment root with src/ workdir */
+	len = path.len;
+	strbuf_addstr(&path, "/src");
+	if (is_nonbare_repository_dir(&path)) {
+		enlistment_is_repo_parent = 1;
+		if (chdir(path.buf) < 0)
+			die_errno(_("could not switch to '%s'"), path.buf);
+	}
+	strbuf_setlen(&path, len);
 
-			enlistment_found = 1;
-			break;
-		}
+	setup_git_directory();
 
-		/* reset to original path */
-		strbuf_setlen(&path, len);
+	if (!the_repository->worktree)
+		die(_("Scalar enlistments require a worktree"));
 
-		/* check if currently in workdir */
-		if (is_nonbare_repository_dir(&path)) {
-			if (enlistment_root) {
-				/*
-				 * If the worktree's directory's name is `src`, the enlistment is the
-				 * parent directory, otherwise it is identical to the worktree.
-				 */
-				root = strip_path_suffix(path.buf, "src");
-				strbuf_addstr(enlistment_root, root ? root : path.buf);
-				free(root);
-			}
-
-			enlistment_found = 1;
-			break;
-		}
-	} while (strbuf_parent_directory(&path));
-
-	if (!enlistment_found)
-		die(_("could not find enlistment root"));
-
-	if (chdir(path.buf) < 0)
-		die_errno(_("could not switch to '%s'"), path.buf);
+	if (enlistment_root) {
+		if (enlistment_is_repo_parent)
+			strbuf_addbuf(enlistment_root, &path);
+		else
+			strbuf_addstr(enlistment_root, the_repository->worktree);
+	}
 
 	strbuf_release(&path);
-	setup_git_directory();
 }
 
 static int run_git(const char *arg, ...)
@@ -115,13 +86,39 @@
 	return res;
 }
 
+struct scalar_config {
+	const char *key;
+	const char *value;
+	int overwrite_on_reconfigure;
+};
+
+static int set_scalar_config(const struct scalar_config *config, int reconfigure)
+{
+	char *value = NULL;
+	int res;
+
+	if ((reconfigure && config->overwrite_on_reconfigure) ||
+	    git_config_get_string(config->key, &value)) {
+		trace2_data_string("scalar", the_repository, config->key, "created");
+		res = git_config_set_gently(config->key, config->value);
+	} else {
+		trace2_data_string("scalar", the_repository, config->key, "exists");
+		res = 0;
+	}
+
+	free(value);
+	return res;
+}
+
+static int have_fsmonitor_support(void)
+{
+	return fsmonitor_ipc__is_supported() &&
+	       fsm_settings__get_reason(the_repository) == FSMONITOR_REASON_OK;
+}
+
 static int set_recommended_config(int reconfigure)
 {
-	struct {
-		const char *key;
-		const char *value;
-		int overwrite_on_reconfigure;
-	} config[] = {
+	struct scalar_config config[] = {
 		/* Required */
 		{ "am.keepCR", "true", 1 },
 		{ "core.FSCache", "true", 1 },
@@ -175,17 +172,16 @@
 	char *value;
 
 	for (i = 0; config[i].key; i++) {
-		if ((reconfigure && config[i].overwrite_on_reconfigure) ||
-		    git_config_get_string(config[i].key, &value)) {
-			trace2_data_string("scalar", the_repository, config[i].key, "created");
-			if (git_config_set_gently(config[i].key,
-						  config[i].value) < 0)
-				return error(_("could not configure %s=%s"),
-					     config[i].key, config[i].value);
-		} else {
-			trace2_data_string("scalar", the_repository, config[i].key, "exists");
-			free(value);
-		}
+		if (set_scalar_config(config + i, reconfigure))
+			return error(_("could not configure %s=%s"),
+				     config[i].key, config[i].value);
+	}
+
+	if (have_fsmonitor_support()) {
+		struct scalar_config fsmonitor = { "core.fsmonitor", "true" };
+		if (set_scalar_config(&fsmonitor, reconfigure))
+			return error(_("could not configure %s=%s"),
+				     fsmonitor.key, fsmonitor.value);
 	}
 
 	/*
@@ -236,125 +232,57 @@
 		       "scalar.repo", the_repository->worktree, NULL);
 }
 
+static int start_fsmonitor_daemon(void)
+{
+	assert(have_fsmonitor_support());
+
+	if (fsmonitor_ipc__get_state() != IPC_STATE__LISTENING)
+		return run_git("fsmonitor--daemon", "start", NULL);
+
+	return 0;
+}
+
+static int stop_fsmonitor_daemon(void)
+{
+	assert(have_fsmonitor_support());
+
+	if (fsmonitor_ipc__get_state() == IPC_STATE__LISTENING)
+		return run_git("fsmonitor--daemon", "stop", NULL);
+
+	return 0;
+}
+
 static int register_dir(void)
 {
-	int res = add_or_remove_enlistment(1);
+	if (add_or_remove_enlistment(1))
+		return error(_("could not add enlistment"));
 
-	if (!res)
-		res = set_recommended_config(0);
+	if (set_recommended_config(0))
+		return error(_("could not set recommended config"));
 
-	if (!res)
-		res = toggle_maintenance(1);
+	if (toggle_maintenance(1))
+		return error(_("could not turn on maintenance"));
 
-	return res;
+	if (have_fsmonitor_support() && start_fsmonitor_daemon()) {
+		return error(_("could not start the FSMonitor daemon"));
+	}
+
+	return 0;
 }
 
 static int unregister_dir(void)
 {
 	int res = 0;
 
-	if (toggle_maintenance(0) < 0)
-		res = -1;
+	if (toggle_maintenance(0))
+		res = error(_("could not turn off maintenance"));
 
-	if (add_or_remove_enlistment(0) < 0)
-		res = -1;
+	if (add_or_remove_enlistment(0))
+		res = error(_("could not remove enlistment"));
 
 	return res;
 }
 
-static int add_directory_to_archiver(struct strvec *archiver_args,
-					  const char *path, int recurse)
-{
-	int at_root = !*path;
-	DIR *dir = opendir(at_root ? "." : path);
-	struct dirent *e;
-	struct strbuf buf = STRBUF_INIT;
-	size_t len;
-	int res = 0;
-
-	if (!dir)
-		return error_errno(_("could not open directory '%s'"), path);
-
-	if (!at_root)
-		strbuf_addf(&buf, "%s/", path);
-	len = buf.len;
-	strvec_pushf(archiver_args, "--prefix=%s", buf.buf);
-
-	while (!res && (e = readdir(dir))) {
-		if (!strcmp(".", e->d_name) || !strcmp("..", e->d_name))
-			continue;
-
-		strbuf_setlen(&buf, len);
-		strbuf_addstr(&buf, e->d_name);
-
-		if (e->d_type == DT_REG)
-			strvec_pushf(archiver_args, "--add-file=%s", buf.buf);
-		else if (e->d_type != DT_DIR)
-			warning(_("skipping '%s', which is neither file nor "
-				  "directory"), buf.buf);
-		else if (recurse &&
-			 add_directory_to_archiver(archiver_args,
-						   buf.buf, recurse) < 0)
-			res = -1;
-	}
-
-	closedir(dir);
-	strbuf_release(&buf);
-	return res;
-}
-
-#ifndef WIN32
-#include <sys/statvfs.h>
-#endif
-
-static int get_disk_info(struct strbuf *out)
-{
-#ifdef WIN32
-	struct strbuf buf = STRBUF_INIT;
-	char volume_name[MAX_PATH], fs_name[MAX_PATH];
-	DWORD serial_number, component_length, flags;
-	ULARGE_INTEGER avail2caller, total, avail;
-
-	strbuf_realpath(&buf, ".", 1);
-	if (!GetDiskFreeSpaceExA(buf.buf, &avail2caller, &total, &avail)) {
-		error(_("could not determine free disk size for '%s'"),
-		      buf.buf);
-		strbuf_release(&buf);
-		return -1;
-	}
-
-	strbuf_setlen(&buf, offset_1st_component(buf.buf));
-	if (!GetVolumeInformationA(buf.buf, volume_name, sizeof(volume_name),
-				   &serial_number, &component_length, &flags,
-				   fs_name, sizeof(fs_name))) {
-		error(_("could not get info for '%s'"), buf.buf);
-		strbuf_release(&buf);
-		return -1;
-	}
-	strbuf_addf(out, "Available space on '%s': ", buf.buf);
-	strbuf_humanise_bytes(out, avail2caller.QuadPart);
-	strbuf_addch(out, '\n');
-	strbuf_release(&buf);
-#else
-	struct strbuf buf = STRBUF_INIT;
-	struct statvfs stat;
-
-	strbuf_realpath(&buf, ".", 1);
-	if (statvfs(buf.buf, &stat) < 0) {
-		error_errno(_("could not determine free disk size for '%s'"),
-			    buf.buf);
-		strbuf_release(&buf);
-		return -1;
-	}
-
-	strbuf_addf(out, "Available space on '%s': ", buf.buf);
-	strbuf_humanise_bytes(out, st_mult(stat.f_bsize, stat.f_bavail));
-	strbuf_addf(out, " (mount flags 0x%lx)\n", stat.f_flag);
-	strbuf_release(&buf);
-#endif
-	return 0;
-}
-
 /* printf-style interface, expects `<key>=<value>` argument */
 static int set_config(const char *fmt, ...)
 {
@@ -431,25 +359,35 @@
 {
 #ifdef WIN32
 	struct strbuf parent = STRBUF_INIT;
+	size_t offset;
+	char *path_sep;
 #endif
 
 	if (unregister_dir())
-		die(_("failed to unregister repository"));
+		return error(_("failed to unregister repository"));
 
 #ifdef WIN32
 	/*
 	 * Change the current directory to one outside of the enlistment so
 	 * that we may delete everything underneath it.
 	 */
-	strbuf_addbuf(&parent, enlistment);
-	strbuf_parent_directory(&parent);
-	if (chdir(parent.buf) < 0)
-		die_errno(_("could not switch to '%s'"), parent.buf);
+	offset = offset_1st_component(enlistment->buf);
+	path_sep = find_last_dir_sep(enlistment->buf + offset);
+	strbuf_add(&parent, enlistment->buf,
+		   path_sep ? path_sep - enlistment->buf : offset);
+	if (chdir(parent.buf) < 0) {
+		int res = error_errno(_("could not switch to '%s'"), parent.buf);
+		strbuf_release(&parent);
+		return res;
+	}
 	strbuf_release(&parent);
 #endif
 
+	if (have_fsmonitor_support() && stop_fsmonitor_daemon())
+		return error(_("failed to stop the FSMonitor daemon"));
+
 	if (remove_dir_recursively(enlistment, 0))
-		die(_("failed to delete enlistment directory"));
+		return error(_("failed to delete enlistment directory"));
 
 	return 0;
 }
@@ -595,83 +533,6 @@
 	return res;
 }
 
-static void dir_file_stats_objects(const char *full_path, size_t full_path_len,
-				   const char *file_name, void *data)
-{
-	struct strbuf *buf = data;
-	struct stat st;
-
-	if (!stat(full_path, &st))
-		strbuf_addf(buf, "%-70s %16" PRIuMAX "\n", file_name,
-			    (uintmax_t)st.st_size);
-}
-
-static int dir_file_stats(struct object_directory *object_dir, void *data)
-{
-	struct strbuf *buf = data;
-
-	strbuf_addf(buf, "Contents of %s:\n", object_dir->path);
-
-	for_each_file_in_pack_dir(object_dir->path, dir_file_stats_objects,
-				  data);
-
-	return 0;
-}
-
-static int count_files(char *path)
-{
-	DIR *dir = opendir(path);
-	struct dirent *e;
-	int count = 0;
-
-	if (!dir)
-		return 0;
-
-	while ((e = readdir(dir)) != NULL)
-		if (!is_dot_or_dotdot(e->d_name) && e->d_type == DT_REG)
-			count++;
-
-	closedir(dir);
-	return count;
-}
-
-static void loose_objs_stats(struct strbuf *buf, const char *path)
-{
-	DIR *dir = opendir(path);
-	struct dirent *e;
-	int count;
-	int total = 0;
-	unsigned char c;
-	struct strbuf count_path = STRBUF_INIT;
-	size_t base_path_len;
-
-	if (!dir)
-		return;
-
-	strbuf_addstr(buf, "Object directory stats for ");
-	strbuf_add_absolute_path(buf, path);
-	strbuf_addstr(buf, ":\n");
-
-	strbuf_add_absolute_path(&count_path, path);
-	strbuf_addch(&count_path, '/');
-	base_path_len = count_path.len;
-
-	while ((e = readdir(dir)) != NULL)
-		if (!is_dot_or_dotdot(e->d_name) &&
-		    e->d_type == DT_DIR && strlen(e->d_name) == 2 &&
-		    !hex_to_bytes(&c, e->d_name, 1)) {
-			strbuf_setlen(&count_path, base_path_len);
-			strbuf_addstr(&count_path, e->d_name);
-			total += (count = count_files(count_path.buf));
-			strbuf_addf(buf, "%s : %7d files\n", e->d_name, count);
-		}
-
-	strbuf_addf(buf, "Total: %d loose objects", total);
-
-	strbuf_release(&count_path);
-	closedir(dir);
-}
-
 static int cmd_diagnose(int argc, const char **argv)
 {
 	struct option options[] = {
@@ -681,107 +542,19 @@
 		N_("scalar diagnose [<enlistment>]"),
 		NULL
 	};
-	struct strbuf zip_path = STRBUF_INIT;
-	struct strvec archiver_args = STRVEC_INIT;
-	char **argv_copy = NULL;
-	int stdout_fd = -1, archiver_fd = -1;
-	time_t now = time(NULL);
-	struct tm tm;
-	struct strbuf path = STRBUF_INIT, buf = STRBUF_INIT;
+	struct strbuf diagnostics_root = STRBUF_INIT;
 	int res = 0;
 
 	argc = parse_options(argc, argv, NULL, options,
 			     usage, 0);
 
-	setup_enlistment_directory(argc, argv, usage, options, &zip_path);
+	setup_enlistment_directory(argc, argv, usage, options, &diagnostics_root);
+	strbuf_addstr(&diagnostics_root, "/.scalarDiagnostics");
 
-	strbuf_addstr(&zip_path, "/.scalarDiagnostics/scalar_");
-	strbuf_addftime(&zip_path,
-			"%Y%m%d_%H%M%S", localtime_r(&now, &tm), 0, 0);
-	strbuf_addstr(&zip_path, ".zip");
-	switch (safe_create_leading_directories(zip_path.buf)) {
-	case SCLD_EXISTS:
-	case SCLD_OK:
-		break;
-	default:
-		error_errno(_("could not create directory for '%s'"),
-			    zip_path.buf);
-		goto diagnose_cleanup;
-	}
-	stdout_fd = dup(1);
-	if (stdout_fd < 0) {
-		res = error_errno(_("could not duplicate stdout"));
-		goto diagnose_cleanup;
-	}
+	res = run_git("diagnose", "--mode=all", "-s", "%Y%m%d_%H%M%S",
+		      "-o", diagnostics_root.buf, NULL);
 
-	archiver_fd = xopen(zip_path.buf, O_CREAT | O_WRONLY | O_TRUNC, 0666);
-	if (archiver_fd < 0 || dup2(archiver_fd, 1) < 0) {
-		res = error_errno(_("could not redirect output"));
-		goto diagnose_cleanup;
-	}
-
-	init_zip_archiver();
-	strvec_pushl(&archiver_args, "scalar-diagnose", "--format=zip", NULL);
-
-	strbuf_reset(&buf);
-	strbuf_addstr(&buf, "Collecting diagnostic info\n\n");
-	get_version_info(&buf, 1);
-
-	strbuf_addf(&buf, "Enlistment root: %s\n", the_repository->worktree);
-	get_disk_info(&buf);
-	write_or_die(stdout_fd, buf.buf, buf.len);
-	strvec_pushf(&archiver_args,
-		     "--add-virtual-file=diagnostics.log:%.*s",
-		     (int)buf.len, buf.buf);
-
-	strbuf_reset(&buf);
-	strbuf_addstr(&buf, "--add-virtual-file=packs-local.txt:");
-	dir_file_stats(the_repository->objects->odb, &buf);
-	foreach_alt_odb(dir_file_stats, &buf);
-	strvec_push(&archiver_args, buf.buf);
-
-	strbuf_reset(&buf);
-	strbuf_addstr(&buf, "--add-virtual-file=objects-local.txt:");
-	loose_objs_stats(&buf, ".git/objects");
-	strvec_push(&archiver_args, buf.buf);
-
-	if ((res = add_directory_to_archiver(&archiver_args, ".git", 0)) ||
-	    (res = add_directory_to_archiver(&archiver_args, ".git/hooks", 0)) ||
-	    (res = add_directory_to_archiver(&archiver_args, ".git/info", 0)) ||
-	    (res = add_directory_to_archiver(&archiver_args, ".git/logs", 1)) ||
-	    (res = add_directory_to_archiver(&archiver_args, ".git/objects/info", 0)))
-		goto diagnose_cleanup;
-
-	strvec_pushl(&archiver_args, "--prefix=",
-		     oid_to_hex(the_hash_algo->empty_tree), "--", NULL);
-
-	/* `write_archive()` modifies the `argv` passed to it. Let it. */
-	argv_copy = xmemdupz(archiver_args.v,
-			     sizeof(char *) * archiver_args.nr);
-	res = write_archive(archiver_args.nr, (const char **)argv_copy, NULL,
-			    the_repository, NULL, 0);
-	if (res) {
-		error(_("failed to write archive"));
-		goto diagnose_cleanup;
-	}
-
-	if (!res)
-		fprintf(stderr, "\n"
-		       "Diagnostics complete.\n"
-		       "All of the gathered info is captured in '%s'\n",
-		       zip_path.buf);
-
-diagnose_cleanup:
-	if (archiver_fd >= 0) {
-		close(1);
-		dup2(stdout_fd, 1);
-	}
-	free(argv_copy);
-	strvec_clear(&archiver_args);
-	strbuf_release(&zip_path);
-	strbuf_release(&path);
-	strbuf_release(&buf);
-
+	strbuf_release(&diagnostics_root);
 	return res;
 }
 
diff --git a/contrib/scalar/scalar.txt b/contrib/scalar/scalar.txt
index c0425e0..1a12dc4 100644
--- a/contrib/scalar/scalar.txt
+++ b/contrib/scalar/scalar.txt
@@ -3,7 +3,7 @@
 
 NAME
 ----
-scalar - an opinionated repository management tool
+scalar - A tool for managing large Git repositories
 
 SYNOPSIS
 --------
@@ -20,10 +20,9 @@
 DESCRIPTION
 -----------
 
-Scalar is an opinionated repository management tool. By creating new
-repositories or registering existing repositories with Scalar, your Git
-experience will speed up. Scalar sets advanced Git config settings,
-maintains your repositories in the background, and helps reduce data sent
+Scalar is a repository management tool that optimizes Git for use in large
+repositories. Scalar improves performance by configuring advanced Git settings,
+maintaining repositories in the background, and helping to reduce data sent
 across the network.
 
 An important Scalar concept is the enlistment: this is the top-level directory
diff --git a/contrib/scalar/t/Makefile b/contrib/scalar/t/Makefile
index 01e82e5..1ed174a 100644
--- a/contrib/scalar/t/Makefile
+++ b/contrib/scalar/t/Makefile
@@ -42,7 +42,7 @@
 	@echo "*** $@ ***"; GIT_CONFIG=.git/config '$(SHELL_PATH_SQ)' $@ $(GIT_TEST_OPTS)
 
 clean-except-prove-cache:
-	$(RM) -r 'trash directory'.* '$(TEST_RESULTS_DIRECTORY_SQ)'
+	$(RM) -r 'trash directory'.*
 	$(RM) -r valgrind/bin
 
 clean: clean-except-prove-cache
diff --git a/contrib/scalar/t/t9099-scalar.sh b/contrib/scalar/t/t9099-scalar.sh
index 10b1172..dfb949f 100755
--- a/contrib/scalar/t/t9099-scalar.sh
+++ b/contrib/scalar/t/t9099-scalar.sh
@@ -17,6 +17,99 @@
 	test_expect_code 129 scalar -h
 '
 
+test_expect_success 'scalar invoked on enlistment root' '
+	test_when_finished rm -rf test src deeper &&
+
+	for enlistment_root in test src deeper/test
+	do
+		git init ${enlistment_root}/src &&
+
+		# Register
+		scalar register ${enlistment_root} &&
+		scalar list >out &&
+		grep "$(pwd)/${enlistment_root}/src\$" out &&
+
+		# Delete (including enlistment root)
+		scalar delete $enlistment_root &&
+		test_path_is_missing $enlistment_root &&
+		scalar list >out &&
+		! grep "^$(pwd)/${enlistment_root}/src\$" out || return 1
+	done
+'
+
+test_expect_success 'scalar invoked on enlistment src repo' '
+	test_when_finished rm -rf test src deeper &&
+
+	for enlistment_root in test src deeper/test
+	do
+		git init ${enlistment_root}/src &&
+
+		# Register
+		scalar register ${enlistment_root}/src &&
+		scalar list >out &&
+		grep "$(pwd)/${enlistment_root}/src\$" out &&
+
+		# Delete (will not include enlistment root)
+		scalar delete ${enlistment_root}/src &&
+		test_path_is_dir $enlistment_root &&
+		scalar list >out &&
+		! grep "^$(pwd)/${enlistment_root}/src\$" out || return 1
+	done
+'
+
+test_expect_success 'scalar invoked when enlistment root and repo are the same' '
+	test_when_finished rm -rf test src deeper &&
+
+	for enlistment_root in test src deeper/test
+	do
+		git init ${enlistment_root} &&
+
+		# Register
+		scalar register ${enlistment_root} &&
+		scalar list >out &&
+		grep "$(pwd)/${enlistment_root}\$" out &&
+
+		# Delete (will not include enlistment root)
+		scalar delete ${enlistment_root} &&
+		test_path_is_missing $enlistment_root &&
+		scalar list >out &&
+		! grep "^$(pwd)/${enlistment_root}\$" out &&
+
+		# Make sure we did not accidentally delete the trash dir
+		test_path_is_dir "$TRASH_DIRECTORY" || return 1
+	done
+'
+
+test_expect_success 'scalar repo search respects GIT_CEILING_DIRECTORIES' '
+	test_when_finished rm -rf test &&
+
+	git init test/src &&
+	mkdir -p test/src/deep &&
+	GIT_CEILING_DIRECTORIES="$(pwd)/test/src" &&
+	! scalar register test/src/deep 2>err &&
+	grep "not a git repository" err
+'
+
+test_expect_success 'scalar enlistments need a worktree' '
+	test_when_finished rm -rf bare test &&
+
+	git init --bare bare/src &&
+	! scalar register bare/src 2>err &&
+	grep "Scalar enlistments require a worktree" err &&
+
+	git init test/src &&
+	! scalar register test/src/.git 2>err &&
+	grep "Scalar enlistments require a worktree" err
+'
+
+test_expect_success FSMONITOR_DAEMON 'scalar register starts fsmon daemon' '
+	git init test/src &&
+	test_must_fail git -C test/src fsmonitor--daemon status &&
+	scalar register test/src &&
+	git -C test/src fsmonitor--daemon status &&
+	test_cmp_config -C test/src true core.fsmonitor
+'
+
 test_expect_success 'scalar unregister' '
 	git init vanish/src &&
 	scalar register vanish/src &&
@@ -109,14 +202,14 @@
 	sed -n "s/.*$SQ\\(.*\\.zip\\)$SQ.*/\\1/p" <err >zip_path &&
 	zip_path=$(cat zip_path) &&
 	test -n "$zip_path" &&
-	unzip -v "$zip_path" &&
+	"$GIT_UNZIP" -v "$zip_path" &&
 	folder=${zip_path%.zip} &&
 	test_path_is_missing "$folder" &&
-	unzip -p "$zip_path" diagnostics.log >out &&
+	"$GIT_UNZIP" -p "$zip_path" diagnostics.log >out &&
 	test_file_not_empty out &&
-	unzip -p "$zip_path" packs-local.txt >out &&
+	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
 	grep "$(pwd)/.git/objects" out &&
-	unzip -p "$zip_path" objects-local.txt >out &&
+	"$GIT_UNZIP" -p "$zip_path" objects-local.txt >out &&
 	grep "^Total: [1-9]" out
 '
 
diff --git a/contrib/subtree/git-subtree.sh b/contrib/subtree/git-subtree.sh
index 1af1d96..7562a39 100755
--- a/contrib/subtree/git-subtree.sh
+++ b/contrib/subtree/git-subtree.sh
@@ -50,6 +50,14 @@
 
 indent=0
 
+# Usage: say [MSG...]
+say () {
+	if test -z "$arg_quiet"
+	then
+		printf '%s\n' "$*"
+	fi
+}
+
 # Usage: debug [MSG...]
 debug () {
 	if test -n "$arg_debug"
@@ -60,7 +68,7 @@
 
 # Usage: progress [MSG...]
 progress () {
-	if test -z "$GIT_QUIET"
+	if test -z "$arg_quiet"
 	then
 		if test -z "$arg_debug"
 		then
@@ -146,6 +154,7 @@
 	eval "$set_args"
 
 	# Begin "real" flag parsing.
+	arg_quiet=
 	arg_debug=
 	arg_prefix=
 	arg_split_branch=
@@ -161,7 +170,7 @@
 
 		case "$opt" in
 		-q)
-			GIT_QUIET=1
+			arg_quiet=1
 			;;
 		-d)
 			arg_debug=1
@@ -252,7 +261,7 @@
 	dir="$(dirname "$arg_prefix/.")"
 
 	debug "command: {$arg_command}"
-	debug "quiet: {$GIT_QUIET}"
+	debug "quiet: {$arg_quiet}"
 	debug "dir: {$dir}"
 	debug "opts: {$*}"
 	debug
diff --git a/contrib/subtree/t/Makefile b/contrib/subtree/t/Makefile
index 276898e..3d278bb 100644
--- a/contrib/subtree/t/Makefile
+++ b/contrib/subtree/t/Makefile
@@ -47,7 +47,7 @@
 	$(RM) -r '$(TEST_RESULTS_DIRECTORY_SQ)'
 
 clean-except-prove-cache:
-	$(RM) -r 'trash directory'.* '$(TEST_RESULTS_DIRECTORY_SQ)'
+	$(RM) -r 'trash directory'.*
 	$(RM) -r valgrind/bin
 
 clean: clean-except-prove-cache
diff --git a/convert.c b/convert.c
index 4d15372..95e6a52 100644
--- a/convert.c
+++ b/convert.c
@@ -619,7 +619,7 @@
 	const char *path;
 };
 
-static int filter_buffer_or_fd(int in, int out, void *data)
+static int filter_buffer_or_fd(int in UNUSED, int out, void *data)
 {
 	/*
 	 * Spawn cmd and feed the buffer contents through its stdin.
@@ -1008,7 +1008,7 @@
 	return 0;
 }
 
-static int read_convert_config(const char *var, const char *value, void *cb)
+static int read_convert_config(const char *var, const char *value, void *cb UNUSED)
 {
 	const char *key, *name;
 	size_t namelen;
diff --git a/delta-islands.c b/delta-islands.c
index aa98b2e..26f9e99 100644
--- a/delta-islands.c
+++ b/delta-islands.c
@@ -316,7 +316,7 @@
 static unsigned int island_regexes_alloc, island_regexes_nr;
 static const char *core_island_name;
 
-static int island_config_callback(const char *k, const char *v, void *cb)
+static int island_config_callback(const char *k, const char *v, void *cb UNUSED)
 {
 	if (!strcmp(k, "pack.island")) {
 		struct strbuf re = STRBUF_INIT;
@@ -365,7 +365,7 @@
 }
 
 static int find_island_for_ref(const char *refname, const struct object_id *oid,
-			       int flags, void *data)
+			       int flags UNUSED, void *data UNUSED)
 {
 	/*
 	 * We should advertise 'ARRAY_SIZE(matches) - 2' as the max,
diff --git a/diagnose.c b/diagnose.c
new file mode 100644
index 0000000..beb0a87
--- /dev/null
+++ b/diagnose.c
@@ -0,0 +1,269 @@
+#include "cache.h"
+#include "diagnose.h"
+#include "compat/disk.h"
+#include "archive.h"
+#include "dir.h"
+#include "help.h"
+#include "strvec.h"
+#include "object-store.h"
+#include "packfile.h"
+
+struct archive_dir {
+	const char *path;
+	int recursive;
+};
+
+struct diagnose_option {
+	enum diagnose_mode mode;
+	const char *option_name;
+};
+
+static struct diagnose_option diagnose_options[] = {
+	{ DIAGNOSE_STATS, "stats" },
+	{ DIAGNOSE_ALL, "all" },
+};
+
+int option_parse_diagnose(const struct option *opt, const char *arg, int unset)
+{
+	int i;
+	enum diagnose_mode *diagnose = opt->value;
+
+	if (!arg) {
+		*diagnose = unset ? DIAGNOSE_NONE : DIAGNOSE_STATS;
+		return 0;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(diagnose_options); i++) {
+		if (!strcmp(arg, diagnose_options[i].option_name)) {
+			*diagnose = diagnose_options[i].mode;
+			return 0;
+		}
+	}
+
+	return error(_("invalid --%s value '%s'"), opt->long_name, arg);
+}
+
+static void dir_file_stats_objects(const char *full_path, size_t full_path_len,
+				   const char *file_name, void *data)
+{
+	struct strbuf *buf = data;
+	struct stat st;
+
+	if (!stat(full_path, &st))
+		strbuf_addf(buf, "%-70s %16" PRIuMAX "\n", file_name,
+			    (uintmax_t)st.st_size);
+}
+
+static int dir_file_stats(struct object_directory *object_dir, void *data)
+{
+	struct strbuf *buf = data;
+
+	strbuf_addf(buf, "Contents of %s:\n", object_dir->path);
+
+	for_each_file_in_pack_dir(object_dir->path, dir_file_stats_objects,
+				  data);
+
+	return 0;
+}
+
+static int count_files(char *path)
+{
+	DIR *dir = opendir(path);
+	struct dirent *e;
+	int count = 0;
+
+	if (!dir)
+		return 0;
+
+	while ((e = readdir(dir)) != NULL)
+		if (!is_dot_or_dotdot(e->d_name) && e->d_type == DT_REG)
+			count++;
+
+	closedir(dir);
+	return count;
+}
+
+static void loose_objs_stats(struct strbuf *buf, const char *path)
+{
+	DIR *dir = opendir(path);
+	struct dirent *e;
+	int count;
+	int total = 0;
+	unsigned char c;
+	struct strbuf count_path = STRBUF_INIT;
+	size_t base_path_len;
+
+	if (!dir)
+		return;
+
+	strbuf_addstr(buf, "Object directory stats for ");
+	strbuf_add_absolute_path(buf, path);
+	strbuf_addstr(buf, ":\n");
+
+	strbuf_add_absolute_path(&count_path, path);
+	strbuf_addch(&count_path, '/');
+	base_path_len = count_path.len;
+
+	while ((e = readdir(dir)) != NULL)
+		if (!is_dot_or_dotdot(e->d_name) &&
+		    e->d_type == DT_DIR && strlen(e->d_name) == 2 &&
+		    !hex_to_bytes(&c, e->d_name, 1)) {
+			strbuf_setlen(&count_path, base_path_len);
+			strbuf_addstr(&count_path, e->d_name);
+			total += (count = count_files(count_path.buf));
+			strbuf_addf(buf, "%s : %7d files\n", e->d_name, count);
+		}
+
+	strbuf_addf(buf, "Total: %d loose objects", total);
+
+	strbuf_release(&count_path);
+	closedir(dir);
+}
+
+static int add_directory_to_archiver(struct strvec *archiver_args,
+				     const char *path, int recurse)
+{
+	int at_root = !*path;
+	DIR *dir;
+	struct dirent *e;
+	struct strbuf buf = STRBUF_INIT;
+	size_t len;
+	int res = 0;
+
+	dir = opendir(at_root ? "." : path);
+	if (!dir) {
+		if (errno == ENOENT) {
+			warning(_("could not archive missing directory '%s'"), path);
+			return 0;
+		}
+		return error_errno(_("could not open directory '%s'"), path);
+	}
+
+	if (!at_root)
+		strbuf_addf(&buf, "%s/", path);
+	len = buf.len;
+	strvec_pushf(archiver_args, "--prefix=%s", buf.buf);
+
+	while (!res && (e = readdir(dir))) {
+		if (!strcmp(".", e->d_name) || !strcmp("..", e->d_name))
+			continue;
+
+		strbuf_setlen(&buf, len);
+		strbuf_addstr(&buf, e->d_name);
+
+		if (e->d_type == DT_REG)
+			strvec_pushf(archiver_args, "--add-file=%s", buf.buf);
+		else if (e->d_type != DT_DIR)
+			warning(_("skipping '%s', which is neither file nor "
+				  "directory"), buf.buf);
+		else if (recurse &&
+			 add_directory_to_archiver(archiver_args,
+						   buf.buf, recurse) < 0)
+			res = -1;
+	}
+
+	closedir(dir);
+	strbuf_release(&buf);
+	return res;
+}
+
+int create_diagnostics_archive(struct strbuf *zip_path, enum diagnose_mode mode)
+{
+	struct strvec archiver_args = STRVEC_INIT;
+	char **argv_copy = NULL;
+	int stdout_fd = -1, archiver_fd = -1;
+	struct strbuf buf = STRBUF_INIT;
+	int res, i;
+	struct archive_dir archive_dirs[] = {
+		{ ".git", 0 },
+		{ ".git/hooks", 0 },
+		{ ".git/info", 0 },
+		{ ".git/logs", 1 },
+		{ ".git/objects/info", 0 }
+	};
+
+	if (mode == DIAGNOSE_NONE) {
+		res = 0;
+		goto diagnose_cleanup;
+	}
+
+	stdout_fd = dup(STDOUT_FILENO);
+	if (stdout_fd < 0) {
+		res = error_errno(_("could not duplicate stdout"));
+		goto diagnose_cleanup;
+	}
+
+	archiver_fd = xopen(zip_path->buf, O_CREAT | O_WRONLY | O_TRUNC, 0666);
+	if (dup2(archiver_fd, STDOUT_FILENO) < 0) {
+		res = error_errno(_("could not redirect output"));
+		goto diagnose_cleanup;
+	}
+
+	init_zip_archiver();
+	strvec_pushl(&archiver_args, "git-diagnose", "--format=zip", NULL);
+
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, "Collecting diagnostic info\n\n");
+	get_version_info(&buf, 1);
+
+	strbuf_addf(&buf, "Repository root: %s\n", the_repository->worktree);
+	get_disk_info(&buf);
+	write_or_die(stdout_fd, buf.buf, buf.len);
+	strvec_pushf(&archiver_args,
+		     "--add-virtual-file=diagnostics.log:%.*s",
+		     (int)buf.len, buf.buf);
+
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, "--add-virtual-file=packs-local.txt:");
+	dir_file_stats(the_repository->objects->odb, &buf);
+	foreach_alt_odb(dir_file_stats, &buf);
+	strvec_push(&archiver_args, buf.buf);
+
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, "--add-virtual-file=objects-local.txt:");
+	loose_objs_stats(&buf, ".git/objects");
+	strvec_push(&archiver_args, buf.buf);
+
+	/* Only include this if explicitly requested */
+	if (mode == DIAGNOSE_ALL) {
+		for (i = 0; i < ARRAY_SIZE(archive_dirs); i++) {
+			if (add_directory_to_archiver(&archiver_args,
+						      archive_dirs[i].path,
+						      archive_dirs[i].recursive)) {
+				res = error_errno(_("could not add directory '%s' to archiver"),
+						  archive_dirs[i].path);
+				goto diagnose_cleanup;
+			}
+		}
+	}
+
+	strvec_pushl(&archiver_args, "--prefix=",
+		     oid_to_hex(the_hash_algo->empty_tree), "--", NULL);
+
+	/* `write_archive()` modifies the `argv` passed to it. Let it. */
+	argv_copy = xmemdupz(archiver_args.v,
+			     sizeof(char *) * archiver_args.nr);
+	res = write_archive(archiver_args.nr, (const char **)argv_copy, NULL,
+			    the_repository, NULL, 0);
+	if (res) {
+		error(_("failed to write archive"));
+		goto diagnose_cleanup;
+	}
+
+	fprintf(stderr, "\n"
+		"Diagnostics complete.\n"
+		"All of the gathered info is captured in '%s'\n",
+		zip_path->buf);
+
+diagnose_cleanup:
+	if (archiver_fd >= 0) {
+		dup2(stdout_fd, STDOUT_FILENO);
+		close(stdout_fd);
+		close(archiver_fd);
+	}
+	free(argv_copy);
+	strvec_clear(&archiver_args);
+	strbuf_release(&buf);
+
+	return res;
+}
diff --git a/diagnose.h b/diagnose.h
new file mode 100644
index 0000000..7a4951a
--- /dev/null
+++ b/diagnose.h
@@ -0,0 +1,17 @@
+#ifndef DIAGNOSE_H
+#define DIAGNOSE_H
+
+#include "strbuf.h"
+#include "parse-options.h"
+
+enum diagnose_mode {
+	DIAGNOSE_NONE,
+	DIAGNOSE_STATS,
+	DIAGNOSE_ALL
+};
+
+int option_parse_diagnose(const struct option *opt, const char *arg, int unset);
+
+int create_diagnostics_archive(struct strbuf *zip_path, enum diagnose_mode mode);
+
+#endif /* DIAGNOSE_H */
diff --git a/diff-no-index.c b/diff-no-index.c
index 9a8b093..18edbdf 100644
--- a/diff-no-index.c
+++ b/diff-no-index.c
@@ -243,7 +243,9 @@
 		  int argc, const char **argv)
 {
 	int i, no_index;
+	int ret = 1;
 	const char *paths[2];
+	char *to_free[ARRAY_SIZE(paths)] = { 0 };
 	struct strbuf replacement = STRBUF_INIT;
 	const char *prefix = revs->prefix;
 	struct option no_index_options[] = {
@@ -265,7 +267,7 @@
 	}
 	FREE_AND_NULL(options);
 	for (i = 0; i < 2; i++) {
-		const char *p = argv[argc - 2 + i];
+		const char *p = argv[i];
 		if (!strcmp(p, "-"))
 			/*
 			 * stdin should be spelled as "-"; if you have
@@ -273,7 +275,7 @@
 			 */
 			p = file_from_standard_input;
 		else if (prefix)
-			p = prefix_filename(prefix, p);
+			p = to_free[i] = prefix_filename(prefix, p);
 		paths[i] = p;
 	}
 
@@ -295,16 +297,20 @@
 	revs->diffopt.flags.exit_with_status = 1;
 
 	if (queue_diff(&revs->diffopt, paths[0], paths[1]))
-		return 1;
+		goto out;
 	diff_set_mnemonic_prefix(&revs->diffopt, "1/", "2/");
 	diffcore_std(&revs->diffopt);
 	diff_flush(&revs->diffopt);
 
-	strbuf_release(&replacement);
-
 	/*
 	 * The return code for --no-index imitates diff(1):
 	 * 0 = no changes, 1 = changes, else error
 	 */
-	return diff_result_code(&revs->diffopt, 0);
+	ret = diff_result_code(&revs->diffopt, 0);
+
+out:
+	for (i = 0; i < ARRAY_SIZE(to_free); i++)
+		free(to_free[i]);
+	strbuf_release(&replacement);
+	return ret;
 }
diff --git a/diff.c b/diff.c
index e71cf75..648f671 100644
--- a/diff.c
+++ b/diff.c
@@ -264,7 +264,8 @@
 	diff_detect_rename_default = DIFF_DETECT_RENAME;
 }
 
-int git_diff_heuristic_config(const char *var, const char *value, void *cb)
+int git_diff_heuristic_config(const char *var, const char *value,
+			      void *cb UNUSED)
 {
 	if (!strcmp(var, "diff.indentheuristic"))
 		diff_indent_heuristic = git_config_bool(var, value);
@@ -916,7 +917,7 @@
 static int interned_diff_symbol_cmp(const void *hashmap_cmp_fn_data,
 				    const struct hashmap_entry *eptr,
 				    const struct hashmap_entry *entry_or_key,
-				    const void *keydata)
+				    const void *keydata UNUSED)
 {
 	const struct diff_options *diffopt = hashmap_cmp_fn_data;
 	const struct emitted_diff_symbol *a, *b;
@@ -1289,7 +1290,6 @@
 {
 	static const char *nneof = " No newline at end of file\n";
 	const char *context, *reset, *set, *set_sign, *meta, *fraginfo;
-	struct strbuf sb = STRBUF_INIT;
 
 	enum diff_symbol s = eds->s;
 	const char *line = eds->line;
@@ -1521,7 +1521,6 @@
 	default:
 		BUG("unknown diff symbol");
 	}
-	strbuf_release(&sb);
 }
 
 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
@@ -3362,23 +3361,23 @@
 	return userdiff_get_textconv(r, one->driver);
 }
 
-static struct strbuf *additional_headers(struct diff_options *o,
-					 const char *path)
+static struct string_list *additional_headers(struct diff_options *o,
+					      const char *path)
 {
 	if (!o->additional_path_headers)
 		return NULL;
 	return strmap_get(o->additional_path_headers, path);
 }
 
-static void add_formatted_headers(struct strbuf *msg,
-				  struct strbuf *more_headers,
+static void add_formatted_header(struct strbuf *msg,
+				  const char *header,
 				  const char *line_prefix,
 				  const char *meta,
 				  const char *reset)
 {
-	char *next, *newline;
+	const char *next, *newline;
 
-	for (next = more_headers->buf; *next; next = newline) {
+	for (next = header; *next; next = newline) {
 		newline = strchrnul(next, '\n');
 		strbuf_addf(msg, "%s%s%.*s%s\n", line_prefix, meta,
 			    (int)(newline - next), next, reset);
@@ -3387,6 +3386,34 @@
 	}
 }
 
+static void add_formatted_headers(struct strbuf *msg,
+				  struct string_list *more_headers,
+				  const char *line_prefix,
+				  const char *meta,
+				  const char *reset)
+{
+	int i;
+
+	for (i = 0; i < more_headers->nr; i++)
+		add_formatted_header(msg, more_headers->items[i].string,
+				     line_prefix, meta, reset);
+}
+
+static int diff_filepair_is_phoney(struct diff_filespec *one,
+				   struct diff_filespec *two)
+{
+	/*
+	 * This function specifically looks for pairs injected by
+	 * create_filepairs_for_header_only_notifications().  Such
+	 * pairs are "phoney" in that they do not represent any
+	 * content or even mode difference, but were inserted because
+	 * diff_queued_diff previously had no pair associated with
+	 * that path but we needed some pair to avoid losing the
+	 * "remerge CONFLICT" header associated with the path.
+	 */
+	return !DIFF_FILE_VALID(one) && !DIFF_FILE_VALID(two);
+}
+
 static void builtin_diff(const char *name_a,
 			 const char *name_b,
 			 struct diff_filespec *one,
@@ -3418,14 +3445,16 @@
 
 	if (o->submodule_format == DIFF_SUBMODULE_LOG &&
 	    (!one->mode || S_ISGITLINK(one->mode)) &&
-	    (!two->mode || S_ISGITLINK(two->mode))) {
+	    (!two->mode || S_ISGITLINK(two->mode)) &&
+	    (!diff_filepair_is_phoney(one, two))) {
 		show_submodule_diff_summary(o, one->path ? one->path : two->path,
 				&one->oid, &two->oid,
 				two->dirty_submodule);
 		return;
 	} else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
 		   (!one->mode || S_ISGITLINK(one->mode)) &&
-		   (!two->mode || S_ISGITLINK(two->mode))) {
+		   (!two->mode || S_ISGITLINK(two->mode)) &&
+		   (!diff_filepair_is_phoney(one, two))) {
 		show_submodule_inline_diff(o, one->path ? one->path : two->path,
 				&one->oid, &two->oid,
 				two->dirty_submodule);
@@ -3445,12 +3474,12 @@
 	b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
 	lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
 	lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
-	if (!DIFF_FILE_VALID(one) && !DIFF_FILE_VALID(two)) {
+	if (diff_filepair_is_phoney(one, two)) {
 		/*
-		 * We should only reach this point for pairs from
+		 * We should only reach this point for pairs generated from
 		 * create_filepairs_for_header_only_notifications().  For
-		 * these, we should avoid the "/dev/null" special casing
-		 * above, meaning we avoid showing such pairs as either
+		 * these, we want to avoid the "/dev/null" special casing
+		 * above, because we do not want such pairs shown as either
 		 * "new file" or "deleted file" below.
 		 */
 		lbl[0] = a_one;
@@ -4314,7 +4343,7 @@
 	const char *set = diff_get_color(use_color, DIFF_METAINFO);
 	const char *reset = diff_get_color(use_color, DIFF_RESET);
 	const char *line_prefix = diff_line_prefix(o);
-	struct strbuf *more_headers = NULL;
+	struct string_list *more_headers = NULL;
 
 	*must_show_header = 1;
 	strbuf_init(msg, PATH_MAX * 2 + 300);
@@ -5650,7 +5679,7 @@
 
 	ac = parse_options(ac, av, prefix, options->parseopts, NULL,
 			   PARSE_OPT_KEEP_DASHDASH |
-			   PARSE_OPT_KEEP_UNKNOWN |
+			   PARSE_OPT_KEEP_UNKNOWN_OPT |
 			   PARSE_OPT_NO_INTERNAL_HELP |
 			   PARSE_OPT_ONE_SHOT |
 			   PARSE_OPT_STOP_AT_NON_OPTION);
@@ -5841,6 +5870,7 @@
 {
 	int include_conflict_headers =
 	    (additional_headers(o, p->one->path) &&
+	     !o->pickaxe_opts &&
 	     (!o->filter || filter_bit_tst(DIFF_STATUS_UNMERGED, o)));
 
 	/*
@@ -5896,6 +5926,8 @@
 	int i;
 	int include_conflict_headers =
 	    (o->additional_path_headers &&
+	     strmap_get_size(o->additional_path_headers) &&
+	     !o->pickaxe_opts &&
 	     (!o->filter || filter_bit_tst(DIFF_STATUS_UNMERGED, o)));
 
 	if (include_conflict_headers)
diff --git a/dir.c b/dir.c
index d7cfb08..7542950 100644
--- a/dir.c
+++ b/dir.c
@@ -655,10 +655,10 @@
 	*patternlen = len;
 }
 
-int pl_hashmap_cmp(const void *unused_cmp_data,
+int pl_hashmap_cmp(const void *cmp_data UNUSED,
 		   const struct hashmap_entry *a,
 		   const struct hashmap_entry *b,
-		   const void *key)
+		   const void *key UNUSED)
 {
 	const struct pattern_entry *ee1 =
 			container_of(a, struct pattern_entry, ent);
@@ -1244,8 +1244,7 @@
 
 int match_pathname(const char *pathname, int pathlen,
 		   const char *base, int baselen,
-		   const char *pattern, int prefix, int patternlen,
-		   unsigned flags)
+		   const char *pattern, int prefix, int patternlen)
 {
 	const char *name;
 	int namelen;
@@ -1347,8 +1346,7 @@
 		if (match_pathname(pathname, pathlen,
 				   pattern->base,
 				   pattern->baselen ? pattern->baselen - 1 : 0,
-				   exclude, prefix, pattern->patternlen,
-				   pattern->flags)) {
+				   exclude, prefix, pattern->patternlen)) {
 			res = pattern;
 			break;
 		}
diff --git a/dir.h b/dir.h
index 7bc8620..674747d 100644
--- a/dir.h
+++ b/dir.h
@@ -414,7 +414,7 @@
 		   const char *, int, int, unsigned);
 int match_pathname(const char *, int,
 		   const char *, int,
-		   const char *, int, int, unsigned);
+		   const char *, int, int);
 
 struct path_pattern *last_matching_pattern(struct dir_struct *dir,
 					   struct index_state *istate,
diff --git a/environment.c b/environment.c
index b3296ce..18d042b 100644
--- a/environment.c
+++ b/environment.c
@@ -56,7 +56,6 @@
 const char *excludes_file;
 enum auto_crlf auto_crlf = AUTO_CRLF_FALSE;
 int read_replace_refs = 1;
-char *git_replace_ref_base;
 enum eol core_eol = EOL_UNSET;
 int global_conv_flags_eol = CONV_EOL_RNDTRP_WARN;
 char *check_roundtrip_encoding = "SHIFT-JIS";
@@ -162,6 +161,7 @@
 
 void setup_git_env(const char *git_dir)
 {
+	char *git_replace_ref_base;
 	const char *shallow_file;
 	const char *replace_ref_base;
 	struct set_gitdir_args args = { NULL };
@@ -182,9 +182,10 @@
 	if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT))
 		read_replace_refs = 0;
 	replace_ref_base = getenv(GIT_REPLACE_REF_BASE_ENVIRONMENT);
-	free(git_replace_ref_base);
 	git_replace_ref_base = xstrdup(replace_ref_base ? replace_ref_base
 							  : "refs/replace/");
+	update_ref_namespace(NAMESPACE_REPLACE, git_replace_ref_base);
+
 	free(git_namespace);
 	git_namespace = expand_namespace(getenv(GIT_NAMESPACE_ENVIRONMENT));
 	shallow_file = getenv(GIT_SHALLOW_FILE_ENVIRONMENT);
@@ -333,10 +334,10 @@
 	setup_git_env(path);
 }
 
-static void update_relative_gitdir(const char *name,
+static void update_relative_gitdir(const char *name UNUSED,
 				   const char *old_cwd,
 				   const char *new_cwd,
-				   void *data)
+				   void *data UNUSED)
 {
 	char *path = reparent_relative_path(old_cwd, new_cwd, get_git_dir());
 	struct tmp_objdir *tmp_objdir = tmp_objdir_unapply_primary_odb();
diff --git a/fetch-pack.c b/fetch-pack.c
index cb6647d..998fc2f 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -26,6 +26,7 @@
 #include "commit-reach.h"
 #include "commit-graph.h"
 #include "sigchain.h"
+#include "mergesort.h"
 
 static int transfer_unpack_limit = -1;
 static int fetch_unpack_limit = -1;
@@ -175,8 +176,10 @@
 	return 0;
 }
 
-static int rev_list_insert_ref_oid(const char *refname, const struct object_id *oid,
-				   int flag, void *cb_data)
+static int rev_list_insert_ref_oid(const char *refname UNUSED,
+				   const struct object_id *oid,
+				   int flag UNUSED,
+				   void *cb_data)
 {
 	return rev_list_insert_ref(cb_data, oid);
 }
@@ -292,6 +295,29 @@
 	return;
 }
 
+static void send_filter(struct fetch_pack_args *args,
+			struct strbuf *req_buf,
+			int server_supports_filter)
+{
+	if (args->filter_options.choice) {
+		const char *spec =
+			expand_list_objects_filter_spec(&args->filter_options);
+		if (server_supports_filter) {
+			print_verbose(args, _("Server supports filter"));
+			packet_buf_write(req_buf, "filter %s", spec);
+			trace2_data_string("fetch", the_repository,
+					   "filter/effective", spec);
+		} else {
+			warning("filtering not recognized by server, ignoring");
+			trace2_data_string("fetch", the_repository,
+					   "filter/unsupported", spec);
+		}
+	} else {
+		trace2_data_string("fetch", the_repository,
+				   "filter/none", "");
+	}
+}
+
 static int find_common(struct fetch_negotiator *negotiator,
 		       struct fetch_pack_args *args,
 		       int fd[2], struct object_id *result_oid,
@@ -299,6 +325,7 @@
 {
 	int fetching;
 	int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
+	int negotiation_round = 0, haves = 0;
 	const struct object_id *oid;
 	unsigned in_vain = 0;
 	int got_continue = 0;
@@ -389,11 +416,7 @@
 			packet_buf_write(&req_buf, "deepen-not %s", s->string);
 		}
 	}
-	if (server_supports_filtering && args->filter_options.choice) {
-		const char *spec =
-			expand_list_objects_filter_spec(&args->filter_options);
-		packet_buf_write(&req_buf, "filter %s", spec);
-	}
+	send_filter(args, &req_buf, server_supports_filtering);
 	packet_buf_flush(&req_buf);
 	state_len = req_buf.len;
 
@@ -441,9 +464,19 @@
 		packet_buf_write(&req_buf, "have %s\n", oid_to_hex(oid));
 		print_verbose(args, "have %s", oid_to_hex(oid));
 		in_vain++;
+		haves++;
 		if (flush_at <= ++count) {
 			int ack;
 
+			negotiation_round++;
+			trace2_region_enter_printf("negotiation_v0_v1", "round",
+						   the_repository, "%d",
+						   negotiation_round);
+			trace2_data_intmax("negotiation_v0_v1", the_repository,
+					   "haves_added", haves);
+			trace2_data_intmax("negotiation_v0_v1", the_repository,
+					   "in_vain", in_vain);
+			haves = 0;
 			packet_buf_flush(&req_buf);
 			send_request(args, fd[1], &req_buf);
 			strbuf_setlen(&req_buf, state_len);
@@ -465,6 +498,9 @@
 						      ack, oid_to_hex(result_oid));
 				switch (ack) {
 				case ACK:
+					trace2_region_leave_printf("negotiation_v0_v1", "round",
+								   the_repository, "%d",
+								   negotiation_round);
 					flushes = 0;
 					multi_ack = 0;
 					retval = 0;
@@ -490,6 +526,7 @@
 						const char *hex = oid_to_hex(result_oid);
 						packet_buf_write(&req_buf, "have %s\n", hex);
 						state_len = req_buf.len;
+						haves++;
 						/*
 						 * Reset in_vain because an ack
 						 * for this commit has not been
@@ -508,6 +545,9 @@
 				}
 			} while (ack);
 			flushes--;
+			trace2_region_leave_printf("negotiation_v0_v1", "round",
+						   the_repository, "%d",
+						   negotiation_round);
 			if (got_continue && MAX_IN_VAIN < in_vain) {
 				print_verbose(args, _("giving up"));
 				break; /* give up */
@@ -518,6 +558,8 @@
 	}
 done:
 	trace2_region_leave("fetch-pack", "negotiation_v0_v1", the_repository);
+	trace2_data_intmax("negotiation_v0_v1", the_repository, "total_rounds",
+			   negotiation_round);
 	if (!got_ready || !no_done) {
 		packet_buf_write(&req_buf, "done\n");
 		send_request(args, fd[1], &req_buf);
@@ -560,8 +602,10 @@
 	return 0;
 }
 
-static int mark_complete_oid(const char *refname, const struct object_id *oid,
-			     int flag, void *cb_data)
+static int mark_complete_oid(const char *refname UNUSED,
+			     const struct object_id *oid,
+			     int flag UNUSED,
+			     void *cb_data UNUSED)
 {
 	return mark_complete(oid);
 }
@@ -799,7 +843,7 @@
 	return retval;
 }
 
-static int sideband_demux(int in, int out, void *data)
+static int sideband_demux(int in UNUSED, int out, void *data)
 {
 	int *xd = data;
 	int ret;
@@ -1025,6 +1069,13 @@
 	return 0;
 }
 
+static int ref_compare_name(const struct ref *a, const struct ref *b)
+{
+	return strcmp(a->name, b->name);
+}
+
+DEFINE_LIST_SORT(static, sort_ref_list, struct ref, next);
+
 static int cmp_ref_by_name(const void *a_, const void *b_)
 {
 	const struct ref *a = *((const struct ref **)a_);
@@ -1323,15 +1374,8 @@
 		die(_("Server does not support shallow requests"));
 
 	/* Add filter */
-	if (server_supports_feature("fetch", "filter", 0) &&
-	    args->filter_options.choice) {
-		const char *spec =
-			expand_list_objects_filter_spec(&args->filter_options);
-		print_verbose(args, _("Server supports filter"));
-		packet_buf_write(&req_buf, "filter %s", spec);
-	} else if (args->filter_options.choice) {
-		warning("filtering not recognized by server, ignoring");
-	}
+	send_filter(args, &req_buf,
+		    server_supports_feature("fetch", "filter", 0));
 
 	if (server_supports_feature("fetch", "packfile-uris", 0)) {
 		int i;
@@ -1361,6 +1405,8 @@
 
 	haves_added = add_haves(negotiator, &req_buf, haves_to_send);
 	*in_vain += haves_added;
+	trace2_data_intmax("negotiation_v2", the_repository, "haves_added", haves_added);
+	trace2_data_intmax("negotiation_v2", the_repository, "in_vain", *in_vain);
 	if (!haves_added || (seen_ack && *in_vain >= MAX_IN_VAIN)) {
 		/* Send Done */
 		packet_buf_write(&req_buf, "done\n");
@@ -1603,6 +1649,7 @@
 	struct oidset common = OIDSET_INIT;
 	struct packet_reader reader;
 	int in_vain = 0, negotiation_started = 0;
+	int negotiation_round = 0;
 	int haves_to_send = INITIAL_FLUSH;
 	struct fetch_negotiator negotiator_alloc;
 	struct fetch_negotiator *negotiator;
@@ -1659,12 +1706,20 @@
 						    "negotiation_v2",
 						    the_repository);
 			}
+			negotiation_round++;
+			trace2_region_enter_printf("negotiation_v2", "round",
+						   the_repository, "%d",
+						   negotiation_round);
 			if (send_fetch_request(negotiator, fd[1], args, ref,
 					       &common,
 					       &haves_to_send, &in_vain,
 					       reader.use_sideband,
-					       seen_ack))
+					       seen_ack)) {
+				trace2_region_leave_printf("negotiation_v2", "round",
+							   the_repository, "%d",
+							   negotiation_round);
 				state = FETCH_GET_PACK;
+			}
 			else
 				state = FETCH_PROCESS_ACKS;
 			break;
@@ -1677,6 +1732,9 @@
 				seen_ack = 1;
 				oidset_insert(&common, &common_oid);
 			}
+			trace2_region_leave_printf("negotiation_v2", "round",
+						   the_repository, "%d",
+						   negotiation_round);
 			if (received_ready) {
 				/*
 				 * Don't check for response delimiter; get_pack() will
@@ -1692,6 +1750,8 @@
 			trace2_region_leave("fetch-pack",
 					    "negotiation_v2",
 					    the_repository);
+			trace2_data_intmax("negotiation_v2", the_repository,
+					   "total_rounds", negotiation_round);
 			/* Check for shallow-info section */
 			if (process_section_header(&reader, "shallow-info", 1))
 				receive_shallow_info(args, &reader, shallows, si);
@@ -2071,6 +2131,7 @@
 	int in_vain = 0;
 	int seen_ack = 0;
 	int last_iteration = 0;
+	int negotiation_round = 0;
 	timestamp_t min_generation = GENERATION_NUMBER_INFINITY;
 
 	fetch_negotiator_init(the_repository, &negotiator);
@@ -2084,11 +2145,17 @@
 			   add_to_object_array,
 			   &nt_object_array);
 
+	trace2_region_enter("fetch-pack", "negotiate_using_fetch", the_repository);
 	while (!last_iteration) {
 		int haves_added;
 		struct object_id common_oid;
 		int received_ready = 0;
 
+		negotiation_round++;
+
+		trace2_region_enter_printf("negotiate_using_fetch", "round",
+					   the_repository, "%d",
+					   negotiation_round);
 		strbuf_reset(&req_buf);
 		write_fetch_command_and_capabilities(&req_buf, server_options);
 
@@ -2099,6 +2166,11 @@
 		if (!haves_added || (seen_ack && in_vain >= MAX_IN_VAIN))
 			last_iteration = 1;
 
+		trace2_data_intmax("negotiate_using_fetch", the_repository,
+				   "haves_added", haves_added);
+		trace2_data_intmax("negotiate_using_fetch", the_repository,
+				   "in_vain", in_vain);
+
 		/* Send request */
 		packet_buf_flush(&req_buf);
 		if (write_in_full(fd[1], req_buf.buf, req_buf.len) < 0)
@@ -2131,7 +2203,13 @@
 						 REACH_SCRATCH, 0,
 						 min_generation))
 			last_iteration = 1;
+		trace2_region_leave_printf("negotiation", "round",
+					   the_repository, "%d",
+					   negotiation_round);
 	}
+	trace2_region_enter("fetch-pack", "negotiate_using_fetch", the_repository);
+	trace2_data_intmax("negotiate_using_fetch", the_repository,
+			   "total_rounds", negotiation_round);
 	clear_common_flag(acked_commits);
 	strbuf_release(&req_buf);
 }
diff --git a/fuzz-commit-graph.c b/fuzz-commit-graph.c
index e7cf6d5..914026f 100644
--- a/fuzz-commit-graph.c
+++ b/fuzz-commit-graph.c
@@ -1,7 +1,7 @@
 #include "commit-graph.h"
 #include "repository.h"
 
-struct commit_graph *parse_commit_graph(struct repository *r,
+struct commit_graph *parse_commit_graph(struct repo_settings *s,
 					void *graph_map, size_t graph_size);
 
 int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
@@ -11,7 +11,15 @@
 	struct commit_graph *g;
 
 	initialize_the_repository();
-	g = parse_commit_graph(the_repository, (void *)data, size);
+	/*
+	 * Initialize the_repository with commit-graph settings that would
+	 * normally be read from the repository's gitdir. We want to avoid
+	 * touching the disk to keep the individual fuzz-test cases as fast as
+	 * possible.
+	 */
+	the_repository->settings.commit_graph_generation_version = 2;
+	the_repository->settings.commit_graph_read_changed_paths = 1;
+	g = parse_commit_graph(&the_repository->settings, (void *)data, size);
 	repo_clear(the_repository);
 	free_commit_graph(g);
 
diff --git a/git-compat-util.h b/git-compat-util.h
index 36a25ae..b90b647 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -189,6 +189,13 @@
 #define _NETBSD_SOURCE 1
 #define _SGI_SOURCE 1
 
+#if defined(__GNUC__)
+#define UNUSED __attribute__((unused)) \
+	__attribute__((deprecated ("parameter declared as UNUSED")))
+#else
+#define UNUSED
+#endif
+
 #if defined(WIN32) && !defined(__CYGWIN__) /* Both MinGW and MSVC */
 # if !defined(_WIN32_WINNT)
 #  define _WIN32_WINNT 0x0600
@@ -261,6 +268,7 @@
 #include <sys/resource.h>
 #include <sys/socket.h>
 #include <sys/ioctl.h>
+#include <sys/statvfs.h>
 #include <termios.h>
 #ifndef NO_SYS_SELECT_H
 #include <sys/select.h>
@@ -397,7 +405,9 @@
 #endif
 
 #ifndef platform_core_config
-static inline int noop_core_config(const char *var, const char *value, void *cb)
+static inline int noop_core_config(const char *var UNUSED,
+				   const char *value UNUSED,
+				   void *cb UNUSED)
 {
 	return 0;
 }
@@ -490,7 +500,8 @@
 	}
 }
 
-static inline int is_path_owned_by_current_uid(const char *path, struct strbuf *report)
+static inline int is_path_owned_by_current_uid(const char *path,
+					       struct strbuf *report UNUSED)
 {
 	struct stat st;
 	uid_t euid;
@@ -568,8 +579,11 @@
 /* The sentinel attribute is valid from gcc version 4.0 */
 #if defined(__GNUC__) && (__GNUC__ >= 4)
 #define LAST_ARG_MUST_BE_NULL __attribute__((sentinel))
+/* warn_unused_result exists as of gcc 3.4.0, but be lazy and check 4.0 */
+#define RESULT_MUST_BE_USED __attribute__ ((warn_unused_result))
 #else
 #define LAST_ARG_MUST_BE_NULL
+#define RESULT_MUST_BE_USED
 #endif
 
 #define MAYBE_UNUSED __attribute__((__unused__))
@@ -998,6 +1012,28 @@
 	return (unsigned long)a;
 }
 
+/*
+ * Limit size of IO chunks, because huge chunks only cause pain.  OS X
+ * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
+ * the absence of bugs, large chunks can result in bad latencies when
+ * you decide to kill the process.
+ *
+ * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
+ * that is smaller than that, clip it to SSIZE_MAX, as a call to
+ * read(2) or write(2) larger than that is allowed to fail.  As the last
+ * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
+ * to override this, if the definition of SSIZE_MAX given by the platform
+ * is broken.
+ */
+#ifndef MAX_IO_SIZE
+# define MAX_IO_SIZE_DEFAULT (8*1024*1024)
+# if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
+#  define MAX_IO_SIZE SSIZE_MAX
+# else
+#  define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
+# endif
+#endif
+
 #ifdef HAVE_ALLOCA_H
 # include <alloca.h>
 # define xalloca(size)      (alloca(size))
diff --git a/git-instaweb.sh b/git-instaweb.sh
index 4349566..c68f494 100755
--- a/git-instaweb.sh
+++ b/git-instaweb.sh
@@ -102,7 +102,7 @@
 
 start_httpd () {
 	if test -f "$fqgitdir/pid"; then
-		say "Instance already running. Restarting..."
+		echo "Instance already running. Restarting..."
 		stop_httpd
 	fi
 
diff --git a/git-merge-resolve.sh b/git-merge-resolve.sh
index 343fe7b..77e9312 100755
--- a/git-merge-resolve.sh
+++ b/git-merge-resolve.sh
@@ -5,6 +5,16 @@
 #
 # Resolve two trees, using enhanced multi-base read-tree.
 
+. git-sh-setup
+
+# Abort if index does not match HEAD
+if ! git diff-index --quiet --cached HEAD --
+then
+    gettextln "Error: Your local changes to the following files would be overwritten by merge"
+    git diff-index --cached --name-only HEAD -- | sed -e 's/^/    /'
+    exit 2
+fi
+
 # The first parameters up to -- are merge bases; the rest are heads.
 bases= head= remotes= sep_seen=
 for arg
diff --git a/git-p4.py b/git-p4.py
index 77dc19d..d26a980 100755
--- a/git-p4.py
+++ b/git-p4.py
@@ -2259,7 +2259,7 @@
                                 raw=True):
                             if regexp.search(line):
                                 if verbose:
-                                    print("got keyword match on %s in %s in %s" % (regex.pattern, line, file))
+                                    print("got keyword match on %s in %s in %s" % (regexp.pattern, line, file))
                                 kwfiles[file] = regexp
                                 break
 
@@ -4402,19 +4402,16 @@
     def renameBranch(self, branch_name):
         """Rename the existing branch to branch_name.N ."""
 
-        found = True
         for i in range(0, 1000):
             backup_branch_name = "{0}.{1}".format(branch_name, i)
             if not gitBranchExists(backup_branch_name):
                 # Copy ref to backup
                 gitUpdateRef(backup_branch_name, branch_name)
                 gitDeleteRef(branch_name)
-                found = True
                 print("renamed old unshelve branch to {0}".format(backup_branch_name))
                 break
-
-        if not found:
-            sys.exit("gave up trying to rename existing branch {0}".format(sync.branch))
+        else:
+            sys.exit("gave up trying to rename existing branch {0}".format(branch_name))
 
     def findLastP4Revision(self, starting_point):
         """Look back from starting_point for the first commit created by git-p4
diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index d92df37..ce273fe 100644
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -57,15 +57,6 @@
 	exit "$status"
 }
 
-GIT_QUIET=
-
-say () {
-	if test -z "$GIT_QUIET"
-	then
-		printf '%s\n' "$*"
-	fi
-}
-
 if test -n "$OPTIONS_SPEC"; then
 	usage() {
 		"$0" -h
@@ -285,13 +276,6 @@
 	parse_ident_from_commit author AUTHOR
 }
 
-# Clear repo-local GIT_* environment variables. Useful when switching to
-# another repository (e.g. when entering a submodule). See also the env
-# list in git_connect()
-clear_local_git_env() {
-	unset $(git rev-parse --local-env-vars)
-}
-
 # Generate a virtual base file for a two-file merge. Uses git apply to
 # remove lines from $1 that are not in $2, leaving only common lines.
 create_virtual_base() {
diff --git a/git-submodule.sh b/git-submodule.sh
index fd0b4a2..5e5d21c 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -30,6 +30,7 @@
 export GIT_PROTOCOL_FROM_USER
 
 command=
+quiet=
 branch=
 force=
 reference=
@@ -40,8 +41,9 @@
 files=
 remote=
 nofetch=
-update=
-prefix=
+rebase=
+merge=
+checkout=
 custom_name=
 depth=
 progress=
@@ -56,17 +58,6 @@
 	n=$(($1 + 0)) 2>/dev/null && test "$n" = "$1"
 }
 
-# Sanitize the local git environment for use within a submodule. We
-# can't simply use clear_local_git_env since we want to preserve some
-# of the settings from GIT_CONFIG_PARAMETERS.
-sanitize_submodule_env()
-{
-	save_config=$GIT_CONFIG_PARAMETERS
-	clear_local_git_env
-	GIT_CONFIG_PARAMETERS=$save_config
-	export GIT_CONFIG_PARAMETERS
-}
-
 #
 # Add a new submodule to the working tree, .gitmodules and the index
 #
@@ -90,7 +81,7 @@
 			force=$1
 			;;
 		-q|--quiet)
-			GIT_QUIET=1
+			quiet=1
 			;;
 		--progress)
 			progress=1
@@ -138,7 +129,7 @@
 		usage
 	fi
 
-	git ${wt_prefix:+-C "$wt_prefix"} ${prefix:+--super-prefix "$prefix"} submodule--helper add ${GIT_QUIET:+--quiet} ${force:+--force} ${progress:+"--progress"} ${branch:+--branch "$branch"} ${reference_path:+--reference "$reference_path"} ${dissociate:+--dissociate} ${custom_name:+--name "$custom_name"} ${depth:+"$depth"} -- "$@"
+	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper add ${quiet:+--quiet} ${force:+--force} ${progress:+"--progress"} ${branch:+--branch "$branch"} ${reference_path:+--reference "$reference_path"} ${dissociate:+--dissociate} ${custom_name:+--name "$custom_name"} ${depth:+"$depth"} -- "$@"
 }
 
 #
@@ -154,7 +145,7 @@
 	do
 		case "$1" in
 		-q|--quiet)
-			GIT_QUIET=1
+			quiet=1
 			;;
 		--recursive)
 			recursive=1
@@ -169,7 +160,7 @@
 		shift
 	done
 
-	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper foreach ${GIT_QUIET:+--quiet} ${recursive:+--recursive} -- "$@"
+	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper foreach ${quiet:+--quiet} ${recursive:+--recursive} -- "$@"
 }
 
 #
@@ -184,7 +175,7 @@
 	do
 		case "$1" in
 		-q|--quiet)
-			GIT_QUIET=1
+			quiet=1
 			;;
 		--)
 			shift
@@ -200,7 +191,7 @@
 		shift
 	done
 
-	git ${wt_prefix:+-C "$wt_prefix"} ${prefix:+--super-prefix "$prefix"} submodule--helper init ${GIT_QUIET:+--quiet} -- "$@"
+	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper init ${quiet:+--quiet} -- "$@"
 }
 
 #
@@ -217,7 +208,7 @@
 			force=$1
 			;;
 		-q|--quiet)
-			GIT_QUIET=1
+			quiet=1
 			;;
 		--all)
 			deinit_all=t
@@ -236,7 +227,7 @@
 		shift
 	done
 
-	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper deinit ${GIT_QUIET:+--quiet} ${force:+--force} ${deinit_all:+--all} -- "$@"
+	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper deinit ${quiet:+--quiet} ${force:+--force} ${deinit_all:+--all} -- "$@"
 }
 
 #
@@ -251,10 +242,7 @@
 	do
 		case "$1" in
 		-q|--quiet)
-			GIT_QUIET=1
-			;;
-		-v)
-			unset GIT_QUIET
+			quiet=1
 			;;
 		--progress)
 			progress=1
@@ -263,7 +251,6 @@
 			init=1
 			;;
 		--require-init)
-			init=1
 			require_init=1
 			;;
 		--remote)
@@ -276,7 +263,7 @@
 			force=$1
 			;;
 		-r|--rebase)
-			update="rebase"
+			rebase=1
 			;;
 		--reference)
 			case "$2" in '') usage ;; esac
@@ -290,13 +277,13 @@
 			dissociate=1
 			;;
 		-m|--merge)
-			update="merge"
+			merge=1
 			;;
 		--recursive)
 			recursive=1
 			;;
 		--checkout)
-			update="checkout"
+			checkout=1
 			;;
 		--recommend-shallow)
 			recommend_shallow="--recommend-shallow"
@@ -349,7 +336,7 @@
 	done
 
 	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper update \
-		${GIT_QUIET:+--quiet} \
+		${quiet:+--quiet} \
 		${force:+--force} \
 		${progress:+"--progress"} \
 		${remote:+--remote} \
@@ -357,8 +344,9 @@
 		${init:+--init} \
 		${nofetch:+--no-fetch} \
 		${wt_prefix:+--prefix "$wt_prefix"} \
-		${prefix:+--recursive-prefix "$prefix"} \
-		${update:+--update "$update"} \
+		${rebase:+--rebase} \
+		${merge:+--merge} \
+		${checkout:+--checkout} \
 		${reference:+"$reference"} \
 		${dissociate:+"--dissociate"} \
 		${depth:+"$depth"} \
@@ -409,7 +397,7 @@
 		shift
 	done
 
-	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper set-branch ${GIT_QUIET:+--quiet} ${branch:+--branch "$branch"} ${default:+--default} -- "$@"
+	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper set-branch ${quiet:+--quiet} ${branch:+--branch "$branch"} ${default:+--default} -- "$@"
 }
 
 #
@@ -422,7 +410,7 @@
 	do
 		case "$1" in
 		-q|--quiet)
-			GIT_QUIET=1
+			quiet=1
 			;;
 		--)
 			shift
@@ -438,7 +426,7 @@
 		shift
 	done
 
-	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper set-url ${GIT_QUIET:+--quiet} -- "$@"
+	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper set-url ${quiet:+--quiet} -- "$@"
 }
 
 #
@@ -459,7 +447,7 @@
 	do
 		case "$1" in
 		--cached)
-			cached="$1"
+			cached=1
 			;;
 		--files)
 			files="$1"
@@ -509,7 +497,7 @@
 	do
 		case "$1" in
 		-q|--quiet)
-			GIT_QUIET=1
+			quiet=1
 			;;
 		--cached)
 			cached=1
@@ -531,7 +519,7 @@
 		shift
 	done
 
-	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper status ${GIT_QUIET:+--quiet} ${cached:+--cached} ${recursive:+--recursive} -- "$@"
+	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper status ${quiet:+--quiet} ${cached:+--cached} ${recursive:+--recursive} -- "$@"
 }
 #
 # Sync remote urls for submodules
@@ -544,7 +532,7 @@
 	do
 		case "$1" in
 		-q|--quiet)
-			GIT_QUIET=1
+			quiet=1
 			shift
 			;;
 		--recursive)
@@ -564,12 +552,12 @@
 		esac
 	done
 
-	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper sync ${GIT_QUIET:+--quiet} ${recursive:+--recursive} -- "$@"
+	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper sync ${quiet:+--quiet} ${recursive:+--recursive} -- "$@"
 }
 
 cmd_absorbgitdirs()
 {
-	git submodule--helper absorb-git-dirs --prefix "$wt_prefix" "$@"
+	git submodule--helper absorbgitdirs --prefix "$wt_prefix" "$@"
 }
 
 # This loop parses the command line arguments to find the
@@ -585,18 +573,10 @@
 		command=$1
 		;;
 	-q|--quiet)
-		GIT_QUIET=1
-		;;
-	-b|--branch)
-		case "$2" in
-		'')
-			usage
-			;;
-		esac
-		branch="$2"; shift
+		quiet=1
 		;;
 	--cached)
-		cached="$1"
+		cached=1
 		;;
 	--)
 		break
@@ -622,12 +602,6 @@
     fi
 fi
 
-# "-b branch" is accepted only by "add" and "set-branch"
-if test -n "$branch" && (test "$command" != add || test "$command" != set-branch)
-then
-	usage
-fi
-
 # "--cached" is accepted only by "status" and "summary"
 if test -n "$cached" && test "$command" != status && test "$command" != summary
 then
diff --git a/git.c b/git.c
index d7a7a82..da411c5 100644
--- a/git.c
+++ b/git.c
@@ -489,14 +489,14 @@
 static struct cmd_struct commands[] = {
 	{ "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 	{ "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
-	{ "annotate", cmd_annotate, RUN_SETUP | NO_PARSEOPT },
+	{ "annotate", cmd_annotate, RUN_SETUP },
 	{ "apply", cmd_apply, RUN_SETUP_GENTLY },
 	{ "archive", cmd_archive, RUN_SETUP_GENTLY },
 	{ "bisect--helper", cmd_bisect__helper, RUN_SETUP },
 	{ "blame", cmd_blame, RUN_SETUP },
 	{ "branch", cmd_branch, RUN_SETUP | DELAY_PAGER_CONFIG },
 	{ "bugreport", cmd_bugreport, RUN_SETUP_GENTLY },
-	{ "bundle", cmd_bundle, RUN_SETUP_GENTLY | NO_PARSEOPT },
+	{ "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 	{ "cat-file", cmd_cat_file, RUN_SETUP },
 	{ "check-attr", cmd_check_attr, RUN_SETUP },
 	{ "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
@@ -514,7 +514,7 @@
 	{ "column", cmd_column, RUN_SETUP_GENTLY },
 	{ "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 	{ "commit-graph", cmd_commit_graph, RUN_SETUP },
-	{ "commit-tree", cmd_commit_tree, RUN_SETUP | NO_PARSEOPT },
+	{ "commit-tree", cmd_commit_tree, RUN_SETUP },
 	{ "config", cmd_config, RUN_SETUP_GENTLY | DELAY_PAGER_CONFIG },
 	{ "count-objects", cmd_count_objects, RUN_SETUP },
 	{ "credential", cmd_credential, RUN_SETUP_GENTLY | NO_PARSEOPT },
@@ -522,6 +522,7 @@
 	{ "credential-cache--daemon", cmd_credential_cache_daemon },
 	{ "credential-store", cmd_credential_store },
 	{ "describe", cmd_describe, RUN_SETUP },
+	{ "diagnose", cmd_diagnose, RUN_SETUP_GENTLY },
 	{ "diff", cmd_diff, NO_PARSEOPT },
 	{ "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
 	{ "diff-index", cmd_diff_index, RUN_SETUP | NO_PARSEOPT },
@@ -553,9 +554,9 @@
 	{ "ls-files", cmd_ls_files, RUN_SETUP },
 	{ "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
 	{ "ls-tree", cmd_ls_tree, RUN_SETUP },
-	{ "mailinfo", cmd_mailinfo, RUN_SETUP_GENTLY | NO_PARSEOPT },
+	{ "mailinfo", cmd_mailinfo, RUN_SETUP_GENTLY },
 	{ "mailsplit", cmd_mailsplit, NO_PARSEOPT },
-	{ "maintenance", cmd_maintenance, RUN_SETUP | NO_PARSEOPT },
+	{ "maintenance", cmd_maintenance, RUN_SETUP },
 	{ "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
 	{ "merge-base", cmd_merge_base, RUN_SETUP },
 	{ "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
@@ -565,8 +566,8 @@
 	{ "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
 	{ "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
 	{ "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
-	{ "merge-tree", cmd_merge_tree, RUN_SETUP | NO_PARSEOPT },
-	{ "mktag", cmd_mktag, RUN_SETUP | NO_PARSEOPT },
+	{ "merge-tree", cmd_merge_tree, RUN_SETUP },
+	{ "mktag", cmd_mktag, RUN_SETUP },
 	{ "mktree", cmd_mktree, RUN_SETUP },
 	{ "multi-pack-index", cmd_multi_pack_index, RUN_SETUP },
 	{ "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
@@ -627,7 +628,7 @@
 	{ "verify-tag", cmd_verify_tag, RUN_SETUP },
 	{ "version", cmd_version },
 	{ "whatchanged", cmd_whatchanged, RUN_SETUP },
-	{ "worktree", cmd_worktree, RUN_SETUP | NO_PARSEOPT },
+	{ "worktree", cmd_worktree, RUN_SETUP },
 	{ "write-tree", cmd_write_tree, RUN_SETUP },
 };
 
diff --git a/gitweb/Makefile b/gitweb/Makefile
index f13e23c..3b68ab2 100644
--- a/gitweb/Makefile
+++ b/gitweb/Makefile
@@ -1,8 +1,8 @@
-# The default target of this Makefile is...
-all::
+ifndef MAK_DIR_GITWEB
+$(error do not run gitweb/Makefile stand-alone anymore. The "gitweb" and \
+"install-gitweb" targets now live in the top-level Makefile)
+endif
 
-# Define V=1 to have a more verbose compile.
-#
 # Define JSMIN to point to JavaScript minifier that functions as
 # a filter to have static/gitweb.js minified.
 #
@@ -10,13 +10,6 @@
 # version of static/gitweb.css
 #
 
-prefix ?= $(HOME)
-bindir ?= $(prefix)/bin
-gitwebdir ?= /var/www/cgi-bin
-
-RM ?= rm -f
-INSTALL ?= install
-
 # default configuration for gitweb
 GITWEB_CONFIG = gitweb_config.perl
 GITWEB_CONFIG_SYSTEM = /etc/gitweb.conf
@@ -30,89 +23,45 @@
 GITWEB_BASE_URL =
 GITWEB_LIST =
 GITWEB_HOMETEXT = indextext.html
-GITWEB_CSS = static/gitweb.css
+GITWEB_CSS_IN = static/gitweb.css
+GITWEB_CSS = $(GITWEB_CSS_IN)
 GITWEB_LOGO = static/git-logo.png
 GITWEB_FAVICON = static/git-favicon.png
-GITWEB_JS = static/gitweb.js
+GITWEB_JS_IN = static/gitweb.js
+GITWEB_JS = $(GITWEB_JS_IN)
 GITWEB_SITE_HTML_HEAD_STRING =
 GITWEB_SITE_HEADER =
 GITWEB_SITE_FOOTER =
 HIGHLIGHT_BIN = highlight
 
-# include user config
--include ../config.mak.autogen
--include ../config.mak
--include config.mak
+# What targets we'll add to 'all' for "make gitweb"
+GITWEB_ALL =
+GITWEB_ALL += gitweb.cgi
+GITWEB_ALL += $(GITWEB_JS)
 
-# determine version
-../GIT-VERSION-FILE: .FORCE-GIT-VERSION-FILE
-	$(QUIET_SUBDIR0)../ $(QUIET_SUBDIR1) GIT-VERSION-FILE
-
-ifneq ($(MAKECMDGOALS),clean)
--include ../GIT-VERSION-FILE
-endif
-
-### Build rules
-
-SHELL_PATH ?= $(SHELL)
-PERL_PATH  ?= /usr/bin/perl
-
-# Shell quote;
-bindir_SQ = $(subst ','\'',$(bindir))#'
-gitwebdir_SQ = $(subst ','\'',$(gitwebdir))#'
-gitwebstaticdir_SQ = $(subst ','\'',$(gitwebdir)/static)#'
-SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))#'
-PERL_PATH_SQ  = $(subst ','\'',$(PERL_PATH))#'
-DESTDIR_SQ    = $(subst ','\'',$(DESTDIR))#'
-
-# Quiet generation (unless V=1)
-QUIET_SUBDIR0  = +$(MAKE) -C # space to separate -C and subdir
-QUIET_SUBDIR1  =
-
-ifneq ($(findstring $(MAKEFLAGS),w),w)
-PRINT_DIR = --no-print-directory
-else # "make -w"
-NO_SUBDIR = :
-endif
-
-ifneq ($(findstring $(MAKEFLAGS),s),s)
-ifndef V
-	QUIET          = @
-	QUIET_GEN      = $(QUIET)echo '   ' GEN $@;
-	QUIET_SUBDIR0  = +@subdir=
-	QUIET_SUBDIR1  = ;$(NO_SUBDIR) echo '   ' SUBDIR $$subdir; \
-	                 $(MAKE) $(PRINT_DIR) -C $$subdir
-	export V
-	export QUIET
-	export QUIET_GEN
-	export QUIET_SUBDIR0
-	export QUIET_SUBDIR1
-endif
-endif
-
-all:: gitweb.cgi static/gitweb.js
+MAK_DIR_GITWEB_ALL = $(addprefix $(MAK_DIR_GITWEB),$(GITWEB_ALL))
 
 GITWEB_PROGRAMS = gitweb.cgi
 
+GITWEB_JS_MIN = static/gitweb.min.js
 ifdef JSMIN
-GITWEB_FILES += static/gitweb.min.js
-GITWEB_JS = static/gitweb.min.js
-all:: static/gitweb.min.js
-static/gitweb.min.js: static/gitweb.js GITWEB-BUILD-OPTIONS
+GITWEB_JS = $(GITWEB_JS_MIN)
+GITWEB_ALL += $(MAK_DIR_GITWEB)$(GITWEB_JS_MIN)
+$(MAK_DIR_GITWEB)$(GITWEB_JS_MIN): $(MAK_DIR_GITWEB)GITWEB-BUILD-OPTIONS
+$(MAK_DIR_GITWEB)$(GITWEB_JS_MIN): $(MAK_DIR_GITWEB)$(GITWEB_JS_IN)
 	$(QUIET_GEN)$(JSMIN) <$< >$@
-else
-GITWEB_FILES += static/gitweb.js
 endif
+GITWEB_FILES += $(GITWEB_JS)
 
+GITWEB_CSS_MIN = static/gitweb.min.css
 ifdef CSSMIN
-GITWEB_FILES += static/gitweb.min.css
-GITWEB_CSS = static/gitweb.min.css
-all:: static/gitweb.min.css
-static/gitweb.min.css: static/gitweb.css GITWEB-BUILD-OPTIONS
+GITWEB_CSS = $(GITWEB_CSS_MIN)
+GITWEB_ALL += $(MAK_DIR_GITWEB)$(GITWEB_CSS_MIN)
+$(MAK_DIR_GITWEB)$(GITWEB_CSS_MIN): $(MAK_DIR_GITWEB)GITWEB-BUILD-OPTIONS
+$(MAK_DIR_GITWEB)$(GITWEB_CSS_MIN): $(MAK_DIR_GITWEB)$(GITWEB_CSS_IN)
 	$(QUIET_GEN)$(CSSMIN) <$< >$@
-else
-GITWEB_FILES += static/gitweb.css
 endif
+GITWEB_FILES += $(GITWEB_CSS)
 
 GITWEB_FILES += static/git-logo.png static/git-favicon.png
 
@@ -120,6 +69,7 @@
 #
 # js/lib/common-lib.js should be always first, then js/lib/*.js,
 # then the rest of files; js/gitweb.js should be last (if it exists)
+GITWEB_JSLIB_FILES =
 GITWEB_JSLIB_FILES += static/js/lib/common-lib.js
 GITWEB_JSLIB_FILES += static/js/lib/datetime.js
 GITWEB_JSLIB_FILES += static/js/lib/cookies.js
@@ -152,46 +102,45 @@
 	-e 's|++GITWEB_SITE_FOOTER++|$(GITWEB_SITE_FOOTER)|g' \
 	-e 's|++HIGHLIGHT_BIN++|$(HIGHLIGHT_BIN)|g'
 
-GITWEB-BUILD-OPTIONS: FORCE
+.PHONY: FORCE
+$(MAK_DIR_GITWEB)GITWEB-BUILD-OPTIONS: FORCE
 	@rm -f $@+
 	@echo "x" '$(PERL_PATH_SQ)' $(GITWEB_REPLACE) "$(JSMIN)|$(CSSMIN)" >$@+
 	@cmp -s $@+ $@ && rm -f $@+ || mv -f $@+ $@
 
-gitweb.cgi: gitweb.perl GITWEB-BUILD-OPTIONS
+$(MAK_DIR_GITWEB)gitweb.cgi: $(MAK_DIR_GITWEB)GITWEB-BUILD-OPTIONS
+$(MAK_DIR_GITWEB)gitweb.cgi: $(MAK_DIR_GITWEB)gitweb.perl
 	$(QUIET_GEN)$(RM) $@ $@+ && \
 	sed -e '1s|#!.*perl|#!$(PERL_PATH_SQ)|' \
 		$(GITWEB_REPLACE) $< >$@+ && \
 	chmod +x $@+ && \
 	mv $@+ $@
 
-static/gitweb.js: $(GITWEB_JSLIB_FILES)
+$(MAK_DIR_GITWEB)static/gitweb.js: $(addprefix $(MAK_DIR_GITWEB),$(GITWEB_JSLIB_FILES))
 	$(QUIET_GEN)$(RM) $@ $@+ && \
 	cat $^ >$@+ && \
 	mv $@+ $@
 
-### Testing rules
-
-test:
-	$(MAKE) -C ../t gitweb-test
-
-test-installed:
-	GITWEB_TEST_INSTALLED='$(DESTDIR_SQ)$(gitwebdir_SQ)' \
-		$(MAKE) -C ../t gitweb-test
-
 ### Installation rules
 
-install: all
+.PHONY: install-gitweb
+install-gitweb: $(MAK_DIR_GITWEB_ALL)
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(gitwebdir_SQ)'
-	$(INSTALL) -m 755 $(GITWEB_PROGRAMS) '$(DESTDIR_SQ)$(gitwebdir_SQ)'
+	$(INSTALL) -m 755 $(addprefix $(MAK_DIR_GITWEB),$(GITWEB_PROGRAMS)) '$(DESTDIR_SQ)$(gitwebdir_SQ)'
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(gitwebstaticdir_SQ)'
-	$(INSTALL) -m 644 $(GITWEB_FILES) '$(DESTDIR_SQ)$(gitwebstaticdir_SQ)'
+	$(INSTALL) -m 644 $(addprefix $(MAK_DIR_GITWEB),$(GITWEB_FILES)) \
+		'$(DESTDIR_SQ)$(gitwebstaticdir_SQ)'
+ifndef NO_GITWEB
+ifndef NO_PERL
+install: install-gitweb
+endif
+endif
 
 ### Cleaning rules
 
-clean:
-	$(RM) gitweb.cgi static/gitweb.js \
-		static/gitweb.min.js static/gitweb.min.css \
-		GITWEB-BUILD-OPTIONS
-
-.PHONY: all clean install test test-installed .FORCE-GIT-VERSION-FILE FORCE
-
+.PHONY: gitweb-clean
+gitweb-clean:
+	$(RM) $(addprefix $(MAK_DIR_GITWEB),gitweb.cgi $(GITWEB_JS_IN) \
+		$(GITWEB_JS_MIN) $(GITWEB_CSS_MIN) \
+		GITWEB-BUILD-OPTIONS)
+clean: gitweb-clean
diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index 1835487..e66eb3d 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -3560,23 +3560,6 @@
 		$title =~ s/^    //;
 		if ($title ne "") {
 			$co{'title'} = chop_str($title, 80, 5);
-			# remove leading stuff of merges to make the interesting part visible
-			if (length($title) > 50) {
-				$title =~ s/^Automatic //;
-				$title =~ s/^merge (of|with) /Merge ... /i;
-				if (length($title) > 50) {
-					$title =~ s/(http|rsync):\/\///;
-				}
-				if (length($title) > 50) {
-					$title =~ s/(master|www|rsync)\.//;
-				}
-				if (length($title) > 50) {
-					$title =~ s/kernel.org:?//;
-				}
-				if (length($title) > 50) {
-					$title =~ s/\/pub\/scm//;
-				}
-			}
 			$co{'title_short'} = chop_str($title, 50, 5);
 			last;
 		}
diff --git a/gpg-interface.c b/gpg-interface.c
index 947b58a..9aa714b 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -165,15 +165,17 @@
 	{ 0, "TRUST_", GPG_STATUS_TRUST_LEVEL },
 };
 
-static struct {
+/* Keep the order same as enum signature_trust_level */
+static struct sigcheck_gpg_trust_level {
 	const char *key;
+	const char *display_key;
 	enum signature_trust_level value;
 } sigcheck_gpg_trust_level[] = {
-	{ "UNDEFINED", TRUST_UNDEFINED },
-	{ "NEVER", TRUST_NEVER },
-	{ "MARGINAL", TRUST_MARGINAL },
-	{ "FULLY", TRUST_FULLY },
-	{ "ULTIMATE", TRUST_ULTIMATE },
+	{ "UNDEFINED", "undefined", TRUST_UNDEFINED },
+	{ "NEVER", "never", TRUST_NEVER },
+	{ "MARGINAL", "marginal", TRUST_MARGINAL },
+	{ "FULLY", "fully", TRUST_FULLY },
+	{ "ULTIMATE", "ultimate", TRUST_ULTIMATE },
 };
 
 static void replace_cstring(char **field, const char *line, const char *next)
@@ -697,7 +699,7 @@
 	configured_signing_key = xstrdup(key);
 }
 
-int git_gpg_config(const char *var, const char *value, void *cb)
+int git_gpg_config(const char *var, const char *value, void *cb UNUSED)
 {
 	struct gpg_format *fmt = NULL;
 	char *fmtname = NULL;
@@ -905,6 +907,20 @@
 	return git_committer_info(IDENT_STRICT | IDENT_NO_DATE);
 }
 
+const char *gpg_trust_level_to_str(enum signature_trust_level level)
+{
+	struct sigcheck_gpg_trust_level *trust;
+
+	if (level < 0 || level >= ARRAY_SIZE(sigcheck_gpg_trust_level))
+		BUG("invalid trust level requested %d", level);
+
+	trust = &sigcheck_gpg_trust_level[level];
+	if (trust->value != level)
+		BUG("sigcheck_gpg_trust_level[] unsorted");
+
+	return sigcheck_gpg_trust_level[level].display_key;
+}
+
 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
 {
 	return use_format->sign_buffer(buffer, signature, signing_key);
diff --git a/gpg-interface.h b/gpg-interface.h
index b30cbdc..8a9ef41 100644
--- a/gpg-interface.h
+++ b/gpg-interface.h
@@ -71,6 +71,14 @@
 int sign_buffer(struct strbuf *buffer, struct strbuf *signature,
 		const char *signing_key);
 
+
+/*
+ * Returns corresponding string in lowercase for a given member of
+ * enum signature_trust_level. For example, `TRUST_ULTIMATE` will
+ * return "ultimate".
+ */
+const char *gpg_trust_level_to_str(enum signature_trust_level level);
+
 int git_gpg_config(const char *, const char *, void *);
 void set_signing_key(const char *);
 const char *get_signing_key(void);
diff --git a/grep.c b/grep.c
index 82eb7da..52a894c 100644
--- a/grep.c
+++ b/grep.c
@@ -1615,7 +1615,7 @@
 				return 0;
 			goto next_line;
 		}
-		if (hit) {
+		if (hit && (opt->max_count < 0 || count < opt->max_count)) {
 			count++;
 			if (opt->status_only)
 				return 1;
diff --git a/grep.h b/grep.h
index c722d25..bdcadce 100644
--- a/grep.h
+++ b/grep.h
@@ -171,6 +171,7 @@
 	int show_hunk_mark;
 	int file_break;
 	int heading;
+	int max_count;
 	void *priv;
 
 	void (*output)(struct grep_opt *opt, const void *data, size_t size);
@@ -181,6 +182,7 @@
 	.relative = 1, \
 	.pathname = 1, \
 	.max_depth = -1, \
+	.max_count = -1, \
 	.pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED, \
 	.colors = { \
 		[GREP_COLOR_CONTEXT] = "", \
diff --git a/hash.h b/hash.h
index 5d40368..36b6416 100644
--- a/hash.h
+++ b/hash.h
@@ -4,9 +4,7 @@
 #include "git-compat-util.h"
 #include "repository.h"
 
-#if defined(SHA1_PPC)
-#include "ppc/sha1.h"
-#elif defined(SHA1_APPLE)
+#if defined(SHA1_APPLE)
 #include <CommonCrypto/CommonDigest.h>
 #elif defined(SHA1_OPENSSL)
 #include <openssl/sha.h>
@@ -16,7 +14,9 @@
 #include "block-sha1/sha1.h"
 #endif
 
-#if defined(SHA256_GCRYPT)
+#if defined(SHA256_NETTLE)
+#include "sha256/nettle.h"
+#elif defined(SHA256_GCRYPT)
 #define SHA256_NEEDS_CLONE_HELPER
 #include "sha256/gcrypt.h"
 #elif defined(SHA256_OPENSSL)
@@ -30,7 +30,7 @@
  * platform's underlying implementation of SHA-1; could be OpenSSL,
  * blk_SHA, Apple CommonCrypto, etc...  Note that the relevant
  * SHA-1 header may have already defined platform_SHA_CTX for our
- * own implementations like block-sha1 and ppc-sha1, so we list
+ * own implementations like block-sha1, so we list
  * the default for OpenSSL compatible SHA-1 implementations here.
  */
 #define platform_SHA_CTX	SHA_CTX
diff --git a/hashmap.c b/hashmap.c
index 134d2ee..cf5fea8 100644
--- a/hashmap.c
+++ b/hashmap.c
@@ -142,10 +142,10 @@
 	return e;
 }
 
-static int always_equal(const void *unused_cmp_data,
-			const struct hashmap_entry *unused1,
-			const struct hashmap_entry *unused2,
-			const void *unused_keydata)
+static int always_equal(const void *cmp_data UNUSED,
+			const struct hashmap_entry *entry1 UNUSED,
+			const struct hashmap_entry *entry2 UNUSED,
+			const void *keydata UNUSED)
 {
 	return 0;
 }
@@ -313,7 +313,7 @@
 	unsigned char data[FLEX_ARRAY];
 };
 
-static int pool_entry_cmp(const void *unused_cmp_data,
+static int pool_entry_cmp(const void *cmp_data UNUSED,
 			  const struct hashmap_entry *eptr,
 			  const struct hashmap_entry *entry_or_key,
 			  const void *keydata)
diff --git a/help.c b/help.c
index 41c41c2..ec670d5 100644
--- a/help.c
+++ b/help.c
@@ -38,19 +38,30 @@
 	{ CAT_plumbinginterrogators, N_("Low-level Commands / Interrogators") },
 	{ CAT_synchingrepositories, N_("Low-level Commands / Syncing Repositories") },
 	{ CAT_purehelpers, N_("Low-level Commands / Internal Helpers") },
+	{ CAT_userinterfaces, N_("User-facing repository, command and file interfaces") },
+	{ CAT_developerinterfaces, N_("Developer-facing file file formats, protocols and interfaces") },
 	{ 0, NULL }
 };
 
 static const char *drop_prefix(const char *name, uint32_t category)
 {
 	const char *new_name;
+	const char *prefix;
 
-	if (skip_prefix(name, "git-", &new_name))
+	switch (category) {
+	case CAT_guide:
+	case CAT_userinterfaces:
+	case CAT_developerinterfaces:
+		prefix = "git";
+		break;
+	default:
+		prefix = "git-";
+		break;
+	}
+	if (skip_prefix(name, prefix, &new_name))
 		return new_name;
-	if (category == CAT_guide && skip_prefix(name, "git", &new_name))
-		return new_name;
+
 	return name;
-
 }
 
 static void extract_cmds(struct cmdname_help **p_cmds, uint32_t mask)
@@ -426,6 +437,26 @@
 	putchar('\n');
 }
 
+void list_user_interfaces_help(void)
+{
+	struct category_description catdesc[] = {
+		{ CAT_userinterfaces, N_("User-facing repository, command and file interfaces:") },
+		{ 0, NULL }
+	};
+	print_cmd_by_category(catdesc, NULL);
+	putchar('\n');
+}
+
+void list_developer_interfaces_help(void)
+{
+	struct category_description catdesc[] = {
+		{ CAT_developerinterfaces, N_("File formats, protocols and other developer interfaces:") },
+		{ 0, NULL }
+	};
+	print_cmd_by_category(catdesc, NULL);
+	putchar('\n');
+}
+
 static int get_alias(const char *var, const char *value, void *data)
 {
 	struct string_list *list = data;
@@ -750,8 +781,9 @@
 	struct string_list *similar_refs;
 };
 
-static int append_similar_ref(const char *refname, const struct object_id *oid,
-			      int flags, void *cb_data)
+static int append_similar_ref(const char *refname,
+			      const struct object_id *oid UNUSED,
+			      int flags UNUSED, void *cb_data)
 {
 	struct similar_ref_cb *cb = (struct similar_ref_cb *)(cb_data);
 	char *branch = strrchr(refname, '/') + 1;
diff --git a/help.h b/help.h
index 971a3ad..af073a7 100644
--- a/help.h
+++ b/help.h
@@ -22,6 +22,8 @@
 void list_common_cmds_help(void);
 void list_all_cmds_help(int show_external_commands, int show_aliases);
 void list_guides_help(void);
+void list_user_interfaces_help(void);
+void list_developer_interfaces_help(void);
 
 void list_all_main_cmds(struct string_list *list);
 void list_all_other_cmds(struct string_list *list);
diff --git a/http-backend.c b/http-backend.c
index 58b83a9..6eb3b2f 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -505,7 +505,7 @@
 }
 
 static int show_text_ref(const char *name, const struct object_id *oid,
-			 int flag, void *cb_data)
+			 int flag UNUSED, void *cb_data)
 {
 	const char *name_nons = strip_namespace(name);
 	struct strbuf *buf = cb_data;
diff --git a/http.c b/http.c
index 168ca30..5d0502f 100644
--- a/http.c
+++ b/http.c
@@ -1775,7 +1775,7 @@
  *   LANGUAGE= LANG=en_US.UTF-8 -> "Accept-Language: en-US, *; q=0.1"
  *   LANGUAGE= LANG=C -> ""
  */
-static const char *get_accept_language(void)
+const char *http_get_accept_language_header(void)
 {
 	if (!cached_accept_language) {
 		struct strbuf buf = STRBUF_INIT;
@@ -1829,7 +1829,7 @@
 					 fwrite_buffer);
 	}
 
-	accept_language = get_accept_language();
+	accept_language = http_get_accept_language_header();
 
 	if (accept_language)
 		headers = curl_slist_append(headers, accept_language);
diff --git a/http.h b/http.h
index ba303cf..3c94c47 100644
--- a/http.h
+++ b/http.h
@@ -178,6 +178,9 @@
 int http_get_info_packs(const char *base_url,
 			struct packed_git **packs_head);
 
+/* Helper for getting Accept-Language header */
+const char *http_get_accept_language_header(void);
+
 struct http_pack_request {
 	char *url;
 
diff --git a/ident.c b/ident.c
index 89ca5b4..6de76f9 100644
--- a/ident.c
+++ b/ident.c
@@ -8,6 +8,7 @@
 #include "cache.h"
 #include "config.h"
 #include "date.h"
+#include "mailmap.h"
 
 static struct strbuf git_default_name = STRBUF_INIT;
 static struct strbuf git_default_email = STRBUF_INIT;
@@ -346,6 +347,79 @@
 	return 0;
 }
 
+/*
+ * Returns the difference between the new and old length of the ident line.
+ */
+static ssize_t rewrite_ident_line(const char *person, size_t len,
+				   struct strbuf *buf,
+				   struct string_list *mailmap)
+{
+	size_t namelen, maillen;
+	const char *name;
+	const char *mail;
+	struct ident_split ident;
+
+	if (split_ident_line(&ident, person, len))
+		return 0;
+
+	mail = ident.mail_begin;
+	maillen = ident.mail_end - ident.mail_begin;
+	name = ident.name_begin;
+	namelen = ident.name_end - ident.name_begin;
+
+	if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
+		struct strbuf namemail = STRBUF_INIT;
+		size_t newlen;
+
+		strbuf_addf(&namemail, "%.*s <%.*s>",
+			    (int)namelen, name, (int)maillen, mail);
+
+		strbuf_splice(buf, ident.name_begin - buf->buf,
+			      ident.mail_end - ident.name_begin + 1,
+			      namemail.buf, namemail.len);
+		newlen = namemail.len;
+
+		strbuf_release(&namemail);
+
+		return newlen - (ident.mail_end - ident.name_begin);
+	}
+
+	return 0;
+}
+
+void apply_mailmap_to_header(struct strbuf *buf, const char **header,
+			       struct string_list *mailmap)
+{
+	size_t buf_offset = 0;
+
+	if (!mailmap)
+		return;
+
+	for (;;) {
+		const char *person, *line;
+		size_t i;
+		int found_header = 0;
+
+		line = buf->buf + buf_offset;
+		if (!*line || *line == '\n')
+			return; /* End of headers */
+
+		for (i = 0; header[i]; i++)
+			if (skip_prefix(line, header[i], &person)) {
+				const char *endp = strchrnul(person, '\n');
+				found_header = 1;
+				buf_offset += endp - line;
+				buf_offset += rewrite_ident_line(person, endp - person, buf, mailmap);
+				break;
+			}
+
+		if (!found_header) {
+			buf_offset = strchrnul(line, '\n') - buf->buf;
+			if (buf->buf[buf_offset] == '\n')
+				buf_offset++;
+		}
+	}
+}
 
 static void ident_env_hint(enum want_ident whose_ident)
 {
@@ -594,7 +668,7 @@
 	return 0;
 }
 
-int git_ident_config(const char *var, const char *value, void *data)
+int git_ident_config(const char *var, const char *value, void *data UNUSED)
 {
 	if (!strcmp(var, "user.useconfigonly")) {
 		ident_use_config_only = git_config_bool(var, value);
diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index 4b25287..6cc4eb8 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -207,7 +207,7 @@
 	struct strbuf buf = STRBUF_INIT;
 	strbuf_addstr_urlencode(&buf, raw, allow_unencoded);
 	trace_printf("Add to combine filter-spec: %s\n", buf.buf);
-	string_list_append(&filter->filter_spec, strbuf_detach(&buf, NULL));
+	string_list_append_nodup(&filter->filter_spec, strbuf_detach(&buf, NULL));
 }
 
 /*
@@ -226,12 +226,13 @@
 			xcalloc(initial_sub_alloc, sizeof(*sub_array));
 		sub_array[0] = *filter_options;
 		memset(filter_options, 0, sizeof(*filter_options));
+		string_list_init_dup(&filter_options->filter_spec);
 		filter_options->sub = sub_array;
 		filter_options->sub_alloc = initial_sub_alloc;
 	}
 	filter_options->sub_nr = 1;
 	filter_options->choice = LOFC_COMBINE;
-	string_list_append(&filter_options->filter_spec, xstrdup("combine:"));
+	string_list_append(&filter_options->filter_spec, "combine:");
 	filter_spec_append_urlencode(
 		filter_options,
 		list_objects_filter_spec(&filter_options->sub[0]));
@@ -256,8 +257,14 @@
 	struct strbuf errbuf = STRBUF_INIT;
 	int parse_error;
 
+	if (!filter_options->filter_spec.strdup_strings) {
+		if (filter_options->filter_spec.nr)
+			BUG("unexpected non-allocated string in filter_spec");
+		filter_options->filter_spec.strdup_strings = 1;
+	}
+
 	if (!filter_options->choice) {
-		string_list_append(&filter_options->filter_spec, xstrdup(arg));
+		string_list_append(&filter_options->filter_spec, arg);
 
 		parse_error = gently_parse_list_objects_filter(
 			filter_options, arg, &errbuf);
@@ -268,7 +275,7 @@
 		 */
 		transform_to_combine_type(filter_options);
 
-		string_list_append(&filter_options->filter_spec, xstrdup("+"));
+		string_list_append(&filter_options->filter_spec, "+");
 		filter_spec_append_urlencode(filter_options, arg);
 		ALLOC_GROW_BY(filter_options->sub, filter_options->sub_nr, 1,
 			      filter_options->sub_alloc);
@@ -306,7 +313,7 @@
 		strbuf_add_separated_string_list(
 			&concatted, "", &filter->filter_spec);
 		string_list_clear(&filter->filter_spec, /*free_util=*/0);
-		string_list_append(
+		string_list_append_nodup(
 			&filter->filter_spec, strbuf_detach(&concatted, NULL));
 	}
 
@@ -321,7 +328,7 @@
 		strbuf_addf(&expanded_spec, "blob:limit=%lu",
 			    filter->blob_limit_value);
 		string_list_clear(&filter->filter_spec, /*free_util=*/0);
-		string_list_append(
+		string_list_append_nodup(
 			&filter->filter_spec,
 			strbuf_detach(&expanded_spec, NULL));
 	}
@@ -418,6 +425,7 @@
 	string_list_init_dup(&dest->filter_spec);
 	for_each_string_list_item(item, &src->filter_spec)
 		string_list_append(&dest->filter_spec, item->string);
+	dest->sparse_oid_name = xstrdup_or_null(src->sparse_oid_name);
 
 	ALLOC_ARRAY(dest->sub, dest->sub_alloc);
 	for (i = 0; i < src->sub_nr; i++)
diff --git a/ll-merge.c b/ll-merge.c
index 14b8362..8955d7e 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -249,7 +249,8 @@
 static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
 static const char *default_ll_merge;
 
-static int read_merge_config(const char *var, const char *value, void *cb)
+static int read_merge_config(const char *var, const char *value,
+			     void *cb UNUSED)
 {
 	struct ll_merge_driver *fn;
 	const char *key, *name;
diff --git a/log-tree.c b/log-tree.c
index d0ac0a6..1dd5fcb 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -135,12 +135,15 @@
 }
 
 static int add_ref_decoration(const char *refname, const struct object_id *oid,
-			      int flags, void *cb_data)
+			      int flags UNUSED,
+			      void *cb_data)
 {
+	int i;
 	struct object *obj;
 	enum object_type objtype;
 	enum decoration_type deco_type = DECORATION_NONE;
 	struct decoration_filter *filter = (struct decoration_filter *)cb_data;
+	const char *git_replace_ref_base = ref_namespace[NAMESPACE_REPLACE].ref;
 
 	if (filter && !ref_filter_match(refname, filter))
 		return 0;
@@ -165,16 +168,21 @@
 		return 0;
 	obj = lookup_object_by_type(the_repository, oid, objtype);
 
-	if (starts_with(refname, "refs/heads/"))
-		deco_type = DECORATION_REF_LOCAL;
-	else if (starts_with(refname, "refs/remotes/"))
-		deco_type = DECORATION_REF_REMOTE;
-	else if (starts_with(refname, "refs/tags/"))
-		deco_type = DECORATION_REF_TAG;
-	else if (!strcmp(refname, "refs/stash"))
-		deco_type = DECORATION_REF_STASH;
-	else if (!strcmp(refname, "HEAD"))
-		deco_type = DECORATION_REF_HEAD;
+	for (i = 0; i < ARRAY_SIZE(ref_namespace); i++) {
+		struct ref_namespace_info *info = &ref_namespace[i];
+
+		if (!info->decoration)
+			continue;
+		if (info->exact) {
+			if (!strcmp(refname, info->ref)) {
+				deco_type = info->decoration;
+				break;
+			}
+		} else if (starts_with(refname, info->ref)) {
+			deco_type = info->decoration;
+			break;
+		}
+	}
 
 	add_name_decoration(deco_type, refname, obj);
 	while (obj->type == OBJ_TAG) {
@@ -956,8 +964,7 @@
 
 static int do_remerge_diff(struct rev_info *opt,
 			   struct commit_list *parents,
-			   struct object_id *oid,
-			   struct commit *commit)
+			   struct object_id *oid)
 {
 	struct merge_options o;
 	struct commit_list *bases;
@@ -1052,7 +1059,7 @@
 					"for octopus merges.\n");
 				return 1;
 			}
-			return do_remerge_diff(opt, parents, oid, commit);
+			return do_remerge_diff(opt, parents, oid);
 		}
 		if (opt->combine_merges)
 			return do_diff_combined(opt, commit);
diff --git a/ls-refs.c b/ls-refs.c
index 98e6937..fa0d01b 100644
--- a/ls-refs.c
+++ b/ls-refs.c
@@ -136,7 +136,8 @@
 	strbuf_release(&namespaced);
 }
 
-static int ls_refs_config(const char *var, const char *value, void *data)
+static int ls_refs_config(const char *var, const char *value,
+			  void *data UNUSED)
 {
 	/*
 	 * We only serve fetches over v2 for now, so respect only "uploadpack"
diff --git a/merge-ort-wrappers.c b/merge-ort-wrappers.c
index ad04106..748924a 100644
--- a/merge-ort-wrappers.c
+++ b/merge-ort-wrappers.c
@@ -10,8 +10,8 @@
 	struct strbuf sb = STRBUF_INIT;
 
 	if (head && repo_index_has_changes(opt->repo, head, &sb)) {
-		fprintf(stderr, _("Your local changes to the following files would be overwritten by merge:\n  %s"),
-		    sb.buf);
+		error(_("Your local changes to the following files would be overwritten by merge:\n  %s"),
+		      sb.buf);
 		strbuf_release(&sb);
 		return -1;
 	}
diff --git a/merge-ort.c b/merge-ort.c
index ebb9a75..99dcee2 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -349,13 +349,15 @@
 	struct mem_pool pool;
 
 	/*
-	 * output: special messages and conflict notices for various paths
+	 * conflicts: logical conflicts and messages stored by _primary_ path
 	 *
 	 * This is a map of pathnames (a subset of the keys in "paths" above)
-	 * to strbufs.  It gathers various warning/conflict/notice messages
-	 * for later processing.
+	 * to struct string_list, with each item's `util` containing a
+	 * `struct logical_conflict_info`. Note, though, that for each path,
+	 * it only stores the logical conflicts for which that path is the
+	 * primary path; the path might be part of additional conflicts.
 	 */
-	struct strmap output;
+	struct strmap conflicts;
 
 	/*
 	 * renames: various data relating to rename detection
@@ -385,8 +387,24 @@
 
 	/* call_depth: recursion level counter for merging merge bases */
 	int call_depth;
+
+	/* field that holds submodule conflict information */
+	struct string_list conflicted_submodules;
 };
 
+struct conflicted_submodule_item {
+	char *abbrev;
+	int flag;
+};
+
+static void conflicted_submodule_item_free(void *util, const char *str)
+{
+	struct conflicted_submodule_item *item = util;
+
+	free(item->abbrev);
+	free(item);
+}
+
 struct version_info {
 	struct object_id oid;
 	unsigned short mode;
@@ -481,6 +499,100 @@
 	unsigned match_mask:3;
 };
 
+enum conflict_and_info_types {
+	/* "Simple" conflicts and informational messages */
+	INFO_AUTO_MERGING = 0,
+	CONFLICT_CONTENTS,       /* text file that failed to merge */
+	CONFLICT_BINARY,
+	CONFLICT_FILE_DIRECTORY,
+	CONFLICT_DISTINCT_MODES,
+	CONFLICT_MODIFY_DELETE,
+
+	/* Regular rename */
+	CONFLICT_RENAME_RENAME,   /* same file renamed differently */
+	CONFLICT_RENAME_COLLIDES, /* rename/add or two files renamed to 1 */
+	CONFLICT_RENAME_DELETE,
+
+	/* Basic directory rename */
+	CONFLICT_DIR_RENAME_SUGGESTED,
+	INFO_DIR_RENAME_APPLIED,
+
+	/* Special directory rename cases */
+	INFO_DIR_RENAME_SKIPPED_DUE_TO_RERENAME,
+	CONFLICT_DIR_RENAME_FILE_IN_WAY,
+	CONFLICT_DIR_RENAME_COLLISION,
+	CONFLICT_DIR_RENAME_SPLIT,
+
+	/* Basic submodule */
+	INFO_SUBMODULE_FAST_FORWARDING,
+	CONFLICT_SUBMODULE_FAILED_TO_MERGE,
+
+	/* Special submodule cases broken out from FAILED_TO_MERGE */
+	CONFLICT_SUBMODULE_FAILED_TO_MERGE_BUT_POSSIBLE_RESOLUTION,
+	CONFLICT_SUBMODULE_NOT_INITIALIZED,
+	CONFLICT_SUBMODULE_HISTORY_NOT_AVAILABLE,
+	CONFLICT_SUBMODULE_MAY_HAVE_REWINDS,
+	CONFLICT_SUBMODULE_NULL_MERGE_BASE,
+
+	/* Keep this entry _last_ in the list */
+	NB_CONFLICT_TYPES,
+};
+
+/*
+ * Short description of conflict type, relied upon by external tools.
+ *
+ * We can add more entries, but DO NOT change any of these strings.  Also,
+ * Order MUST match conflict_info_and_types.
+ */
+static const char *type_short_descriptions[] = {
+	/*** "Simple" conflicts and informational messages ***/
+	[INFO_AUTO_MERGING] = "Auto-merging",
+	[CONFLICT_CONTENTS] = "CONFLICT (contents)",
+	[CONFLICT_BINARY] = "CONFLICT (binary)",
+	[CONFLICT_FILE_DIRECTORY] = "CONFLICT (file/directory)",
+	[CONFLICT_DISTINCT_MODES] = "CONFLICT (distinct modes)",
+	[CONFLICT_MODIFY_DELETE] = "CONFLICT (modify/delete)",
+
+	/*** Regular rename ***/
+	[CONFLICT_RENAME_RENAME] = "CONFLICT (rename/rename)",
+	[CONFLICT_RENAME_COLLIDES] = "CONFLICT (rename involved in collision)",
+	[CONFLICT_RENAME_DELETE] = "CONFLICT (rename/delete)",
+
+	/*** Basic directory rename ***/
+	[CONFLICT_DIR_RENAME_SUGGESTED] =
+		"CONFLICT (directory rename suggested)",
+	[INFO_DIR_RENAME_APPLIED] = "Path updated due to directory rename",
+
+	/*** Special directory rename cases ***/
+	[INFO_DIR_RENAME_SKIPPED_DUE_TO_RERENAME] =
+		"Directory rename skipped since directory was renamed on both sides",
+	[CONFLICT_DIR_RENAME_FILE_IN_WAY] =
+		"CONFLICT (file in way of directory rename)",
+	[CONFLICT_DIR_RENAME_COLLISION] = "CONFLICT(directory rename collision)",
+	[CONFLICT_DIR_RENAME_SPLIT] = "CONFLICT(directory rename unclear split)",
+
+	/*** Basic submodule ***/
+	[INFO_SUBMODULE_FAST_FORWARDING] = "Fast forwarding submodule",
+	[CONFLICT_SUBMODULE_FAILED_TO_MERGE] = "CONFLICT (submodule)",
+
+	/*** Special submodule cases broken out from FAILED_TO_MERGE ***/
+	[CONFLICT_SUBMODULE_FAILED_TO_MERGE_BUT_POSSIBLE_RESOLUTION] =
+		"CONFLICT (submodule with possible resolution)",
+	[CONFLICT_SUBMODULE_NOT_INITIALIZED] =
+		"CONFLICT (submodule not initialized)",
+	[CONFLICT_SUBMODULE_HISTORY_NOT_AVAILABLE] =
+		"CONFLICT (submodule history not available)",
+	[CONFLICT_SUBMODULE_MAY_HAVE_REWINDS] =
+		"CONFLICT (submodule may have rewinds)",
+	[CONFLICT_SUBMODULE_NULL_MERGE_BASE] =
+		"CONFLICT (submodule lacks merge base)"
+};
+
+struct logical_conflict_info {
+	enum conflict_and_info_types type;
+	struct strvec paths;
+};
+
 /*** Function Grouping: various utility functions ***/
 
 /*
@@ -567,24 +679,32 @@
 		struct strmap_entry *e;
 
 		/* Release and free each strbuf found in output */
-		strmap_for_each_entry(&opti->output, &iter, e) {
-			struct strbuf *sb = e->value;
-			strbuf_release(sb);
+		strmap_for_each_entry(&opti->conflicts, &iter, e) {
+			struct string_list *list = e->value;
+			for (int i = 0; i < list->nr; i++) {
+				struct logical_conflict_info *info =
+					list->items[i].util;
+				strvec_clear(&info->paths);
+			}
 			/*
-			 * While strictly speaking we don't need to free(sb)
-			 * here because we could pass free_values=1 when
-			 * calling strmap_clear() on opti->output, that would
-			 * require strmap_clear to do another
-			 * strmap_for_each_entry() loop, so we just free it
-			 * while we're iterating anyway.
+			 * While strictly speaking we don't need to
+			 * free(conflicts) here because we could pass
+			 * free_values=1 when calling strmap_clear() on
+			 * opti->conflicts, that would require strmap_clear
+			 * to do another strmap_for_each_entry() loop, so we
+			 * just free it while we're iterating anyway.
 			 */
-			free(sb);
+			string_list_clear(list, 1);
+			free(list);
 		}
-		strmap_clear(&opti->output, 0);
+		strmap_clear(&opti->conflicts, 0);
 	}
 
 	mem_pool_discard(&opti->pool, 0);
 
+	string_list_clear_func(&opti->conflicted_submodules,
+					conflicted_submodule_item_free);
+
 	/* Clean out callback_data as well. */
 	FREE_AND_NULL(renames->callback_data);
 	renames->callback_data_nr = renames->callback_data_alloc = 0;
@@ -627,29 +747,57 @@
 	strbuf_addch(sb, '\n');
 }
 
-__attribute__((format (printf, 4, 5)))
+__attribute__((format (printf, 8, 9)))
 static void path_msg(struct merge_options *opt,
-		     const char *path,
+		     enum conflict_and_info_types type,
 		     int omittable_hint, /* skippable under --remerge-diff */
+		     const char *primary_path,
+		     const char *other_path_1, /* may be NULL */
+		     const char *other_path_2, /* may be NULL */
+		     struct string_list *other_paths, /* may be NULL */
 		     const char *fmt, ...)
 {
 	va_list ap;
-	struct strbuf *sb, *dest;
+	struct string_list *path_conflicts;
+	struct logical_conflict_info *info;
+	struct strbuf buf = STRBUF_INIT;
+	struct strbuf *dest;
 	struct strbuf tmp = STRBUF_INIT;
 
+	/* Sanity checks */
+	assert(omittable_hint ==
+	       !starts_with(type_short_descriptions[type], "CONFLICT") ||
+	       type == CONFLICT_DIR_RENAME_SUGGESTED);
 	if (opt->record_conflict_msgs_as_headers && omittable_hint)
 		return; /* Do not record mere hints in headers */
 	if (opt->priv->call_depth && opt->verbosity < 5)
 		return; /* Ignore messages from inner merges */
 
-	sb = strmap_get(&opt->priv->output, path);
-	if (!sb) {
-		sb = xmalloc(sizeof(*sb));
-		strbuf_init(sb, 0);
-		strmap_put(&opt->priv->output, path, sb);
+	/* Ensure path_conflicts (ptr to array of logical_conflict) allocated */
+	path_conflicts = strmap_get(&opt->priv->conflicts, primary_path);
+	if (!path_conflicts) {
+		path_conflicts = xmalloc(sizeof(*path_conflicts));
+		string_list_init_dup(path_conflicts);
+		strmap_put(&opt->priv->conflicts, primary_path, path_conflicts);
 	}
 
-	dest = (opt->record_conflict_msgs_as_headers ? &tmp : sb);
+	/* Add a logical_conflict at the end to store info from this call */
+	info = xcalloc(1, sizeof(*info));
+	info->type = type;
+	strvec_init(&info->paths);
+
+	/* Handle the list of paths */
+	strvec_push(&info->paths, primary_path);
+	if (other_path_1)
+		strvec_push(&info->paths, other_path_1);
+	if (other_path_2)
+		strvec_push(&info->paths, other_path_2);
+	if (other_paths)
+		for (int i = 0; i < other_paths->nr; i++)
+		strvec_push(&info->paths, other_paths->items[i].string);
+
+	/* Handle message and its format, in normal case */
+	dest = (opt->record_conflict_msgs_as_headers ? &tmp : &buf);
 
 	va_start(ap, fmt);
 	if (opt->priv->call_depth) {
@@ -660,32 +808,32 @@
 	strbuf_vaddf(dest, fmt, ap);
 	va_end(ap);
 
+	/* Handle specialized formatting of message under --remerge-diff */
 	if (opt->record_conflict_msgs_as_headers) {
 		int i_sb = 0, i_tmp = 0;
 
 		/* Start with the specified prefix */
 		if (opt->msg_header_prefix)
-			strbuf_addf(sb, "%s ", opt->msg_header_prefix);
+			strbuf_addf(&buf, "%s ", opt->msg_header_prefix);
 
 		/* Copy tmp to sb, adding spaces after newlines */
-		strbuf_grow(sb, sb->len + 2*tmp.len); /* more than sufficient */
+		strbuf_grow(&buf, buf.len + 2*tmp.len); /* more than sufficient */
 		for (; i_tmp < tmp.len; i_tmp++, i_sb++) {
 			/* Copy next character from tmp to sb */
-			sb->buf[sb->len + i_sb] = tmp.buf[i_tmp];
+			buf.buf[buf.len + i_sb] = tmp.buf[i_tmp];
 
 			/* If we copied a newline, add a space */
 			if (tmp.buf[i_tmp] == '\n')
-				sb->buf[++i_sb] = ' ';
+				buf.buf[++i_sb] = ' ';
 		}
 		/* Update length and ensure it's NUL-terminated */
-		sb->len += i_sb;
-		sb->buf[sb->len] = '\0';
+		buf.len += i_sb;
+		buf.buf[buf.len] = '\0';
 
 		strbuf_release(&tmp);
 	}
-
-	/* Add final newline character to sb */
-	strbuf_addch(sb, '\n');
+	string_list_append_nodup(path_conflicts, strbuf_detach(&buf, NULL))
+		->util = info;
 }
 
 static struct diff_filespec *pool_alloc_filespec(struct mem_pool *pool,
@@ -1614,38 +1762,50 @@
 
 	int i;
 	int search = !opt->priv->call_depth;
+	int sub_not_initialized = 1;
+	int sub_flag = CONFLICT_SUBMODULE_FAILED_TO_MERGE;
 
 	/* store fallback answer in result in case we fail */
 	oidcpy(result, opt->priv->call_depth ? o : a);
 
 	/* we can not handle deletion conflicts */
-	if (is_null_oid(o))
-		return 0;
-	if (is_null_oid(a))
-		return 0;
-	if (is_null_oid(b))
-		return 0;
+	if (is_null_oid(a) || is_null_oid(b))
+		BUG("submodule deleted on one side; this should be handled outside of merge_submodule()");
 
-	if (repo_submodule_init(&subrepo, opt->repo, path, null_oid())) {
-		path_msg(opt, path, 0,
-				_("Failed to merge submodule %s (not checked out)"),
-				path);
-		return 0;
+	if ((sub_not_initialized = repo_submodule_init(&subrepo,
+		opt->repo, path, null_oid()))) {
+		path_msg(opt, CONFLICT_SUBMODULE_NOT_INITIALIZED, 0,
+			 path, NULL, NULL, NULL,
+			 _("Failed to merge submodule %s (not checked out)"),
+			 path);
+		sub_flag = CONFLICT_SUBMODULE_NOT_INITIALIZED;
+		goto cleanup;
+	}
+
+	if (is_null_oid(o)) {
+		path_msg(opt, CONFLICT_SUBMODULE_NULL_MERGE_BASE, 0,
+			 path, NULL, NULL, NULL,
+			 _("Failed to merge submodule %s (no merge base)"),
+			 path);
+		goto cleanup;
 	}
 
 	if (!(commit_o = lookup_commit_reference(&subrepo, o)) ||
 	    !(commit_a = lookup_commit_reference(&subrepo, a)) ||
 	    !(commit_b = lookup_commit_reference(&subrepo, b))) {
-		path_msg(opt, path, 0,
+		path_msg(opt, CONFLICT_SUBMODULE_HISTORY_NOT_AVAILABLE, 0,
+			 path, NULL, NULL, NULL,
 			 _("Failed to merge submodule %s (commits not present)"),
 			 path);
+		sub_flag = CONFLICT_SUBMODULE_HISTORY_NOT_AVAILABLE;
 		goto cleanup;
 	}
 
 	/* check whether both changes are forward */
 	if (!repo_in_merge_bases(&subrepo, commit_o, commit_a) ||
 	    !repo_in_merge_bases(&subrepo, commit_o, commit_b)) {
-		path_msg(opt, path, 0,
+		path_msg(opt, CONFLICT_SUBMODULE_MAY_HAVE_REWINDS, 0,
+			 path, NULL, NULL, NULL,
 			 _("Failed to merge submodule %s "
 			   "(commits don't follow merge-base)"),
 			 path);
@@ -1655,7 +1815,8 @@
 	/* Case #1: a is contained in b or vice versa */
 	if (repo_in_merge_bases(&subrepo, commit_a, commit_b)) {
 		oidcpy(result, b);
-		path_msg(opt, path, 1,
+		path_msg(opt, INFO_SUBMODULE_FAST_FORWARDING, 1,
+			 path, NULL, NULL, NULL,
 			 _("Note: Fast-forwarding submodule %s to %s"),
 			 path, oid_to_hex(b));
 		ret = 1;
@@ -1663,7 +1824,8 @@
 	}
 	if (repo_in_merge_bases(&subrepo, commit_b, commit_a)) {
 		oidcpy(result, a);
-		path_msg(opt, path, 1,
+		path_msg(opt, INFO_SUBMODULE_FAST_FORWARDING, 1,
+			 path, NULL, NULL, NULL,
 			 _("Note: Fast-forwarding submodule %s to %s"),
 			 path, oid_to_hex(a));
 		ret = 1;
@@ -1686,30 +1848,27 @@
 					 &merges);
 	switch (parent_count) {
 	case 0:
-		path_msg(opt, path, 0, _("Failed to merge submodule %s"), path);
+		path_msg(opt, CONFLICT_SUBMODULE_FAILED_TO_MERGE, 0,
+			 path, NULL, NULL, NULL,
+			 _("Failed to merge submodule %s"), path);
 		break;
 
 	case 1:
 		format_commit(&sb, 4, &subrepo,
 			      (struct commit *)merges.objects[0].item);
-		path_msg(opt, path, 0,
+		path_msg(opt, CONFLICT_SUBMODULE_FAILED_TO_MERGE_BUT_POSSIBLE_RESOLUTION, 0,
+			 path, NULL, NULL, NULL,
 			 _("Failed to merge submodule %s, but a possible merge "
-			   "resolution exists:\n%s\n"),
+			   "resolution exists: %s"),
 			 path, sb.buf);
-		path_msg(opt, path, 1,
-			 _("If this is correct simply add it to the index "
-			   "for example\n"
-			   "by using:\n\n"
-			   "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
-			   "which will accept this suggestion.\n"),
-			 oid_to_hex(&merges.objects[0].item->oid), path);
 		strbuf_release(&sb);
 		break;
 	default:
 		for (i = 0; i < merges.nr; i++)
 			format_commit(&sb, 4, &subrepo,
 				      (struct commit *)merges.objects[i].item);
-		path_msg(opt, path, 0,
+		path_msg(opt, CONFLICT_SUBMODULE_FAILED_TO_MERGE_BUT_POSSIBLE_RESOLUTION, 0,
+			 path, NULL, NULL, NULL,
 			 _("Failed to merge submodule %s, but multiple "
 			   "possible merges exist:\n%s"), path, sb.buf);
 		strbuf_release(&sb);
@@ -1717,7 +1876,23 @@
 
 	object_array_clear(&merges);
 cleanup:
-	repo_clear(&subrepo);
+	if (!opt->priv->call_depth && !ret) {
+		struct string_list *csub = &opt->priv->conflicted_submodules;
+		struct conflicted_submodule_item *util;
+		const char *abbrev;
+
+		util = xmalloc(sizeof(*util));
+		util->flag = sub_flag;
+		util->abbrev = NULL;
+		if (!sub_not_initialized) {
+			abbrev = repo_find_unique_abbrev(&subrepo, b, DEFAULT_ABBREV);
+			util->abbrev = xstrdup(abbrev);
+		}
+		string_list_append(csub, path)->util = util;
+	}
+
+	if (!sub_not_initialized)
+		repo_clear(&subrepo);
 	return ret;
 }
 
@@ -1835,7 +2010,8 @@
 				&src1, name1, &src2, name2,
 				&opt->priv->attr_index, &ll_opts);
 	if (merge_status == LL_MERGE_BINARY_CONFLICT)
-		path_msg(opt, path, 0,
+		path_msg(opt, CONFLICT_BINARY, 0,
+			 path, NULL, NULL, NULL,
 			 "warning: Cannot merge binary files: %s (%s vs. %s)",
 			 path, name1, name2);
 
@@ -1947,7 +2123,8 @@
 		if (ret)
 			return -1;
 		clean &= (merge_status == 0);
-		path_msg(opt, path, 1, _("Auto-merging %s"), path);
+		path_msg(opt, INFO_AUTO_MERGING, 1, path, NULL, NULL, NULL,
+			 _("Auto-merging %s"), path);
 	} else if (S_ISGITLINK(a->mode)) {
 		int two_way = ((S_IFMT & o->mode) != (S_IFMT & a->mode));
 		clean = merge_submodule(opt, pathnames[0],
@@ -2085,21 +2262,24 @@
 		c_info->reported_already = 1;
 		strbuf_add_separated_string_list(&collision_paths, ", ",
 						 &c_info->source_files);
-		path_msg(opt, new_path, 0,
-			 _("CONFLICT (implicit dir rename): Existing file/dir "
-			   "at %s in the way of implicit directory rename(s) "
-			   "putting the following path(s) there: %s."),
-		       new_path, collision_paths.buf);
+		path_msg(opt, CONFLICT_DIR_RENAME_FILE_IN_WAY, 0,
+			 new_path, NULL, NULL, &c_info->source_files,
+			 _("CONFLICT (implicit dir rename): Existing "
+			   "file/dir at %s in the way of implicit "
+			   "directory rename(s) putting the following "
+			   "path(s) there: %s."),
+			 new_path, collision_paths.buf);
 		clean = 0;
 	} else if (c_info->source_files.nr > 1) {
 		c_info->reported_already = 1;
 		strbuf_add_separated_string_list(&collision_paths, ", ",
 						 &c_info->source_files);
-		path_msg(opt, new_path, 0,
-			 _("CONFLICT (implicit dir rename): Cannot map more "
-			   "than one path to %s; implicit directory renames "
-			   "tried to put these paths there: %s"),
-		       new_path, collision_paths.buf);
+		path_msg(opt, CONFLICT_DIR_RENAME_COLLISION, 0,
+			 new_path, NULL, NULL, &c_info->source_files,
+			 _("CONFLICT (implicit dir rename): Cannot map "
+			   "more than one path to %s; implicit directory "
+			   "renames tried to put these paths there: %s"),
+			 new_path, collision_paths.buf);
 		clean = 0;
 	}
 
@@ -2153,13 +2333,14 @@
 			continue;
 
 		if (bad_max == max) {
-			path_msg(opt, source_dir, 0,
-			       _("CONFLICT (directory rename split): "
-				 "Unclear where to rename %s to; it was "
-				 "renamed to multiple other directories, with "
-				 "no destination getting a majority of the "
-				 "files."),
-			       source_dir);
+			path_msg(opt, CONFLICT_DIR_RENAME_SPLIT, 0,
+				 source_dir, NULL, NULL, NULL,
+				 _("CONFLICT (directory rename split): "
+				   "Unclear where to rename %s to; it was "
+				   "renamed to multiple other directories, "
+				   "with no destination getting a majority of "
+				   "the files."),
+				 source_dir);
 			*clean = 0;
 		} else {
 			strmap_put(&renames->dir_renames[side],
@@ -2334,7 +2515,8 @@
 	new_dir = rename_info->value; /* old_dir = rename_info->key; */
 	otherinfo = strmap_get_entry(dir_rename_exclusions, new_dir);
 	if (otherinfo) {
-		path_msg(opt, rename_info->key, 1,
+		path_msg(opt, INFO_DIR_RENAME_SKIPPED_DUE_TO_RERENAME, 1,
+			 rename_info->key, path, new_dir, NULL,
 			 _("WARNING: Avoiding applying %s -> %s rename "
 			   "to %s, because %s itself was renamed."),
 			 rename_info->key, new_dir, path, new_dir);
@@ -2475,14 +2657,16 @@
 	if (opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_TRUE) {
 		/* Notify user of updated path */
 		if (pair->status == 'A')
-			path_msg(opt, new_path, 1,
+			path_msg(opt, INFO_DIR_RENAME_APPLIED, 1,
+				 new_path, old_path, NULL, NULL,
 				 _("Path updated: %s added in %s inside a "
 				   "directory that was renamed in %s; moving "
 				   "it to %s."),
 				 old_path, branch_with_new_path,
 				 branch_with_dir_rename, new_path);
 		else
-			path_msg(opt, new_path, 1,
+			path_msg(opt, INFO_DIR_RENAME_APPLIED, 1,
+				 new_path, old_path, NULL, NULL,
 				 _("Path updated: %s renamed to %s in %s, "
 				   "inside a directory that was renamed in %s; "
 				   "moving it to %s."),
@@ -2495,7 +2679,8 @@
 		 */
 		ci->path_conflict = 1;
 		if (pair->status == 'A')
-			path_msg(opt, new_path, 1,
+			path_msg(opt, CONFLICT_DIR_RENAME_SUGGESTED, 1,
+				 new_path, old_path, NULL, NULL,
 				 _("CONFLICT (file location): %s added in %s "
 				   "inside a directory that was renamed in %s, "
 				   "suggesting it should perhaps be moved to "
@@ -2503,7 +2688,8 @@
 				 old_path, branch_with_new_path,
 				 branch_with_dir_rename, new_path);
 		else
-			path_msg(opt, new_path, 1,
+			path_msg(opt, CONFLICT_DIR_RENAME_SUGGESTED, 1,
+				 new_path, old_path, NULL, NULL,
 				 _("CONFLICT (file location): %s renamed to %s "
 				   "in %s, inside a directory that was renamed "
 				   "in %s, suggesting it should perhaps be "
@@ -2659,7 +2845,8 @@
 			 * and remove the setting of base->path_conflict to 1.
 			 */
 			base->path_conflict = 1;
-			path_msg(opt, oldpath, 0,
+			path_msg(opt, CONFLICT_RENAME_RENAME, 0,
+				 pathnames[0], pathnames[1], pathnames[2], NULL,
 				 _("CONFLICT (rename/rename): %s renamed to "
 				   "%s in %s and to %s in %s."),
 				 pathnames[0],
@@ -2754,7 +2941,8 @@
 			memcpy(&newinfo->stages[target_index], &merged,
 			       sizeof(merged));
 			if (!clean) {
-				path_msg(opt, newpath, 0,
+				path_msg(opt, CONFLICT_RENAME_COLLIDES, 0,
+					 newpath, oldpath, NULL, NULL,
 					 _("CONFLICT (rename involved in "
 					   "collision): rename of %s -> %s has "
 					   "content conflicts AND collides "
@@ -2773,7 +2961,8 @@
 			 */
 
 			newinfo->path_conflict = 1;
-			path_msg(opt, newpath, 0,
+			path_msg(opt, CONFLICT_RENAME_DELETE, 0,
+				 newpath, oldpath, NULL, NULL,
 				 _("CONFLICT (rename/delete): %s renamed "
 				   "to %s in %s, but deleted in %s."),
 				 oldpath, newpath, rename_branch, delete_branch);
@@ -2797,7 +2986,8 @@
 			} else if (source_deleted) {
 				/* rename/delete */
 				newinfo->path_conflict = 1;
-				path_msg(opt, newpath, 0,
+				path_msg(opt, CONFLICT_RENAME_DELETE, 0,
+					 newpath, oldpath, NULL, NULL,
 					 _("CONFLICT (rename/delete): %s renamed"
 					   " to %s in %s, but deleted in %s."),
 					 oldpath, newpath,
@@ -3712,7 +3902,8 @@
 		path = unique_path(opt, path, branch);
 		strmap_put(&opt->priv->paths, path, new_ci);
 
-		path_msg(opt, path, 0,
+		path_msg(opt, CONFLICT_FILE_DIRECTORY, 0,
+			 path, old_path, NULL, NULL,
 			 _("CONFLICT (file/directory): directory in the way "
 			   "of %s from %s; moving it to %s instead."),
 			 old_path, branch, path);
@@ -3788,15 +3979,23 @@
 				rename_b = 1;
 			}
 
+			if (rename_a)
+				a_path = unique_path(opt, path, opt->branch1);
+			if (rename_b)
+				b_path = unique_path(opt, path, opt->branch2);
+
 			if (rename_a && rename_b) {
-				path_msg(opt, path, 0,
+				path_msg(opt, CONFLICT_DISTINCT_MODES, 0,
+					 path, a_path, b_path, NULL,
 					 _("CONFLICT (distinct types): %s had "
 					   "different types on each side; "
 					   "renamed both of them so each can "
 					   "be recorded somewhere."),
 					 path);
 			} else {
-				path_msg(opt, path, 0,
+				path_msg(opt, CONFLICT_DISTINCT_MODES, 0,
+					 path, rename_a ? a_path : b_path,
+					 NULL, NULL,
 					 _("CONFLICT (distinct types): %s had "
 					   "different types on each side; "
 					   "renamed one of them so each can be "
@@ -3833,14 +4032,10 @@
 
 			/* Insert entries into opt->priv_paths */
 			assert(rename_a || rename_b);
-			if (rename_a) {
-				a_path = unique_path(opt, path, opt->branch1);
+			if (rename_a)
 				strmap_put(&opt->priv->paths, a_path, ci);
-			}
 
-			if (rename_b)
-				b_path = unique_path(opt, path, opt->branch2);
-			else
+			if (!rename_b)
 				b_path = path;
 			strmap_put(&opt->priv->paths, b_path, new_ci);
 
@@ -3891,7 +4086,8 @@
 				reason = _("add/add");
 			if (S_ISGITLINK(merged_file.mode))
 				reason = _("submodule");
-			path_msg(opt, path, 0,
+			path_msg(opt, CONFLICT_CONTENTS, 0,
+				 path, NULL, NULL, NULL,
 				 _("CONFLICT (%s): Merge conflict in %s"),
 				 reason, path);
 		}
@@ -3935,7 +4131,8 @@
 			 * since the contents were not modified.
 			 */
 		} else {
-			path_msg(opt, path, 0,
+			path_msg(opt, CONFLICT_MODIFY_DELETE, 0,
+				 path, NULL, NULL, NULL,
 				 _("CONFLICT (modify/delete): %s deleted in %s "
 				   "and modified in %s.  Version %s of %s left "
 				   "in tree."),
@@ -4223,21 +4420,8 @@
 			 * the CE_SKIP_WORKTREE bit and manually write those
 			 * files to the working disk here.
 			 */
-			if (ce_skip_worktree(ce)) {
-				struct stat st;
-
-				if (!lstat(path, &st)) {
-					char *new_name = unique_path(opt,
-								     path,
-								     "cruft");
-
-					path_msg(opt, path, 1,
-						 _("Note: %s not up to date and in way of checking out conflicted version; old copy renamed to %s"),
-						 path, new_name);
-					errs |= rename(path, new_name);
-				}
+			if (ce_skip_worktree(ce))
 				errs |= checkout_entry(ce, &state, NULL, NULL);
-			}
 
 			/*
 			 * Mark this cache entry for removal and instead add
@@ -4279,6 +4463,152 @@
 	return errs;
 }
 
+static void print_submodule_conflict_suggestion(struct string_list *csub) {
+	struct string_list_item *item;
+	struct strbuf msg = STRBUF_INIT;
+	struct strbuf tmp = STRBUF_INIT;
+	struct strbuf subs = STRBUF_INIT;
+
+	if (!csub->nr)
+		return;
+
+	strbuf_add_separated_string_list(&subs, " ", csub);
+	for_each_string_list_item(item, csub) {
+		struct conflicted_submodule_item *util = item->util;
+
+		/*
+		 * NEEDSWORK: The steps to resolve these errors deserve a more
+		 * detailed explanation than what is currently printed below.
+		 */
+		if (util->flag == CONFLICT_SUBMODULE_NOT_INITIALIZED ||
+		    util->flag == CONFLICT_SUBMODULE_HISTORY_NOT_AVAILABLE)
+			continue;
+
+		/*
+		 * TRANSLATORS: This is a line of advice to resolve a merge
+		 * conflict in a submodule. The first argument is the submodule
+		 * name, and the second argument is the abbreviated id of the
+		 * commit that needs to be merged.  For example:
+		 *  - go to submodule (mysubmodule), and either merge commit abc1234"
+		 */
+		strbuf_addf(&tmp, _(" - go to submodule (%s), and either merge commit %s\n"
+				    "   or update to an existing commit which has merged those changes\n"),
+			    item->string, util->abbrev);
+	}
+
+	/*
+	 * TRANSLATORS: This is a detailed message for resolving submodule
+	 * conflicts.  The first argument is string containing one step per
+	 * submodule.  The second is a space-separated list of submodule names.
+	 */
+	strbuf_addf(&msg,
+		    _("Recursive merging with submodules currently only supports trivial cases.\n"
+		      "Please manually handle the merging of each conflicted submodule.\n"
+		      "This can be accomplished with the following steps:\n"
+		      "%s"
+		      " - come back to superproject and run:\n\n"
+		      "      git add %s\n\n"
+		      "   to record the above merge or update\n"
+		      " - resolve any other conflicts in the superproject\n"
+		      " - commit the resulting index in the superproject\n"),
+		    tmp.buf, subs.buf);
+
+	printf("%s", msg.buf);
+
+	strbuf_release(&subs);
+	strbuf_release(&tmp);
+	strbuf_release(&msg);
+}
+
+void merge_display_update_messages(struct merge_options *opt,
+				   int detailed,
+				   struct merge_result *result)
+{
+	struct merge_options_internal *opti = result->priv;
+	struct hashmap_iter iter;
+	struct strmap_entry *e;
+	struct string_list olist = STRING_LIST_INIT_NODUP;
+
+	if (opt->record_conflict_msgs_as_headers)
+		BUG("Either display conflict messages or record them as headers, not both");
+
+	trace2_region_enter("merge", "display messages", opt->repo);
+
+	/* Hack to pre-allocate olist to the desired size */
+	ALLOC_GROW(olist.items, strmap_get_size(&opti->conflicts),
+		   olist.alloc);
+
+	/* Put every entry from output into olist, then sort */
+	strmap_for_each_entry(&opti->conflicts, &iter, e) {
+		string_list_append(&olist, e->key)->util = e->value;
+	}
+	string_list_sort(&olist);
+
+	/* Iterate over the items, printing them */
+	for (int path_nr = 0; path_nr < olist.nr; ++path_nr) {
+		struct string_list *conflicts = olist.items[path_nr].util;
+		for (int i = 0; i < conflicts->nr; i++) {
+			struct logical_conflict_info *info =
+				conflicts->items[i].util;
+
+			if (detailed) {
+				printf("%lu", (unsigned long)info->paths.nr);
+				putchar('\0');
+				for (int n = 0; n < info->paths.nr; n++) {
+					fputs(info->paths.v[n], stdout);
+					putchar('\0');
+				}
+				fputs(type_short_descriptions[info->type],
+				      stdout);
+				putchar('\0');
+			}
+			puts(conflicts->items[i].string);
+			if (detailed)
+				putchar('\0');
+		}
+	}
+	string_list_clear(&olist, 0);
+
+	print_submodule_conflict_suggestion(&opti->conflicted_submodules);
+
+	/* Also include needed rename limit adjustment now */
+	diff_warn_rename_limit("merge.renamelimit",
+			       opti->renames.needed_limit, 0);
+
+	trace2_region_leave("merge", "display messages", opt->repo);
+}
+
+void merge_get_conflicted_files(struct merge_result *result,
+				struct string_list *conflicted_files)
+{
+	struct hashmap_iter iter;
+	struct strmap_entry *e;
+	struct merge_options_internal *opti = result->priv;
+
+	strmap_for_each_entry(&opti->conflicted, &iter, e) {
+		const char *path = e->key;
+		struct conflict_info *ci = e->value;
+		int i;
+
+		VERIFY_CI(ci);
+
+		for (i = MERGE_BASE; i <= MERGE_SIDE2; i++) {
+			struct stage_info *si;
+
+			if (!(ci->filemask & (1ul << i)))
+				continue;
+
+			si = xmalloc(sizeof(*si));
+			si->stage = i+1;
+			si->mode = ci->stages[i].mode;
+			oidcpy(&si->oid, &ci->stages[i].oid);
+			string_list_append(conflicted_files, path)->util = si;
+		}
+	}
+	/* string_list_sort() uses a stable sort, so we're good */
+	string_list_sort(conflicted_files);
+}
+
 void merge_switch_to_result(struct merge_options *opt,
 			    struct tree *head,
 			    struct merge_result *result,
@@ -4321,43 +4651,8 @@
 		fclose(fp);
 		trace2_region_leave("merge", "write_auto_merge", opt->repo);
 	}
-
-	if (display_update_msgs) {
-		struct merge_options_internal *opti = result->priv;
-		struct hashmap_iter iter;
-		struct strmap_entry *e;
-		struct string_list olist = STRING_LIST_INIT_NODUP;
-		int i;
-
-		if (opt->record_conflict_msgs_as_headers)
-			BUG("Either display conflict messages or record them as headers, not both");
-
-		trace2_region_enter("merge", "display messages", opt->repo);
-
-		/* Hack to pre-allocate olist to the desired size */
-		ALLOC_GROW(olist.items, strmap_get_size(&opti->output),
-			   olist.alloc);
-
-		/* Put every entry from output into olist, then sort */
-		strmap_for_each_entry(&opti->output, &iter, e) {
-			string_list_append(&olist, e->key)->util = e->value;
-		}
-		string_list_sort(&olist);
-
-		/* Iterate over the items, printing them */
-		for (i = 0; i < olist.nr; ++i) {
-			struct strbuf *sb = olist.items[i].util;
-
-			printf("%s", sb->buf);
-		}
-		string_list_clear(&olist, 0);
-
-		/* Also include needed rename limit adjustment now */
-		diff_warn_rename_limit("merge.renamelimit",
-				       opti->renames.needed_limit, 0);
-
-		trace2_region_leave("merge", "display messages", opt->repo);
-	}
+	if (display_update_msgs)
+		merge_display_update_messages(opt, /* detailed */ 0, result);
 
 	merge_finalize(opt, result);
 }
@@ -4477,6 +4772,7 @@
 	trace2_region_enter("merge", "allocate/init", opt->repo);
 	if (opt->priv) {
 		clear_or_reinit_internal_opts(opt->priv, 1);
+		string_list_init_nodup(&opt->priv->conflicted_submodules);
 		trace2_region_leave("merge", "allocate/init", opt->repo);
 		return;
 	}
@@ -4531,11 +4827,11 @@
 	strmap_init_with_options(&opt->priv->conflicted, pool, 0);
 
 	/*
-	 * keys & strbufs in output will sometimes need to outlive "paths",
-	 * so it will have a copy of relevant keys.  It's probably a small
-	 * subset of the overall paths that have special output.
+	 * keys & string_lists in conflicts will sometimes need to outlive
+	 * "paths", so it will have a copy of relevant keys.  It's probably
+	 * a small subset of the overall paths that have special output.
 	 */
-	strmap_init(&opt->priv->output);
+	strmap_init(&opt->priv->conflicts);
 
 	trace2_region_leave("merge", "allocate/init", opt->repo);
 }
@@ -4636,7 +4932,8 @@
 	trace2_region_leave("merge", "process_entries", opt->repo);
 
 	/* Set return values */
-	result->path_messages = &opt->priv->output;
+	result->path_messages = &opt->priv->conflicts;
+
 	result->tree = parse_tree_indirect(&working_tree_oid);
 	/* existence of conflicted entries implies unclean */
 	result->clean &= strmap_empty(&opt->priv->conflicted);
diff --git a/merge-ort.h b/merge-ort.h
index fe599b8..a994c9a 100644
--- a/merge-ort.h
+++ b/merge-ort.h
@@ -2,6 +2,7 @@
 #define MERGE_ORT_H
 
 #include "merge-recursive.h"
+#include "hash.h"
 
 struct commit;
 struct tree;
@@ -27,7 +28,7 @@
 	/*
 	 * Special messages and conflict notices for various paths
 	 *
-	 * This is a map of pathnames to strbufs.  It contains various
+	 * This is a map of pathnames to a string_list. It contains various
 	 * warning/conflict/notice messages (possibly multiple per path)
 	 * that callers may want to use.
 	 */
@@ -80,6 +81,35 @@
 			    int update_worktree_and_index,
 			    int display_update_msgs);
 
+/*
+ * Display messages about conflicts and which files were 3-way merged.
+ * Automatically called by merge_switch_to_result() with stream == stdout,
+ * so only call this when bypassing merge_switch_to_result().
+ */
+void merge_display_update_messages(struct merge_options *opt,
+				   int detailed,
+				   struct merge_result *result);
+
+struct stage_info {
+	struct object_id oid;
+	int mode;
+	int stage;
+};
+
+/*
+ * Provide a list of path -> {struct stage_info*} mappings for
+ * all conflicted files.  Note that each path could appear up to three
+ * times in the list, corresponding to 3 different stage entries.  In short,
+ * this basically provides the info that would be printed by `ls-files -u`.
+ *
+ * result should have been populated by a call to
+ * one of the merge_incore_[non]recursive() functions.
+ *
+ * conflicted_files should be empty before calling this function.
+ */
+void merge_get_conflicted_files(struct merge_result *result,
+				struct string_list *conflicted_files);
+
 /* Do needed cleanup when not calling merge_switch_to_result() */
 void merge_finalize(struct merge_options *opt,
 		    struct merge_result *result);
diff --git a/merge-recursive.c b/merge-recursive.c
index b83a129..4ddd3ad 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -45,7 +45,7 @@
 	char path[FLEX_ARRAY];
 };
 
-static int path_hashmap_cmp(const void *cmp_data,
+static int path_hashmap_cmp(const void *cmp_data UNUSED,
 			    const struct hashmap_entry *eptr,
 			    const struct hashmap_entry *entry_or_key,
 			    const void *keydata)
@@ -89,10 +89,10 @@
 	return hashmap_get_entry(hashmap, &key, ent, NULL);
 }
 
-static int dir_rename_cmp(const void *unused_cmp_data,
+static int dir_rename_cmp(const void *cmp_data UNUSED,
 			  const struct hashmap_entry *eptr,
 			  const struct hashmap_entry *entry_or_key,
-			  const void *unused_keydata)
+			  const void *keydata UNUSED)
 {
 	const struct dir_rename_entry *e1, *e2;
 
@@ -134,10 +134,10 @@
 	return hashmap_get_entry(hashmap, &key, ent, NULL);
 }
 
-static int collision_cmp(const void *unused_cmp_data,
+static int collision_cmp(const void *cmp_data UNUSED,
 			 const struct hashmap_entry *eptr,
 			 const struct hashmap_entry *entry_or_key,
-			 const void *unused_keydata)
+			 const void *keydata UNUSED)
 {
 	const struct collision_entry *e1, *e2;
 
@@ -456,7 +456,7 @@
 	clear_unpack_trees_porcelain(&opt->priv->unpack_opts);
 }
 
-static int save_files_dirs(const struct object_id *oid,
+static int save_files_dirs(const struct object_id *oid UNUSED,
 			   struct strbuf *base, const char *path,
 			   unsigned int mode, void *context)
 {
diff --git a/mergesort.c b/mergesort.c
deleted file mode 100644
index bd9c6ef..0000000
--- a/mergesort.c
+++ /dev/null
@@ -1,84 +0,0 @@
-#include "cache.h"
-#include "mergesort.h"
-
-/* Combine two sorted lists.  Take from `list` on equality. */
-static void *llist_merge(void *list, void *other,
-			 void *(*get_next_fn)(const void *),
-			 void (*set_next_fn)(void *, void *),
-			 int (*compare_fn)(const void *, const void *))
-{
-	void *result = list, *tail;
-
-	if (compare_fn(list, other) > 0) {
-		result = other;
-		goto other;
-	}
-	for (;;) {
-		do {
-			tail = list;
-			list = get_next_fn(list);
-			if (!list) {
-				set_next_fn(tail, other);
-				return result;
-			}
-		} while (compare_fn(list, other) <= 0);
-		set_next_fn(tail, other);
-	other:
-		do {
-			tail = other;
-			other = get_next_fn(other);
-			if (!other) {
-				set_next_fn(tail, list);
-				return result;
-			}
-		} while (compare_fn(list, other) > 0);
-		set_next_fn(tail, list);
-	}
-}
-
-/*
- * Perform an iterative mergesort using an array of sublists.
- *
- * n is the number of items.
- * ranks[i] is undefined if n & 2^i == 0, and assumed empty.
- * ranks[i] contains a sublist of length 2^i otherwise.
- *
- * The number of bits in a void pointer limits the number of objects
- * that can be created, and thus the number of array elements necessary
- * to be able to sort any valid list.
- *
- * Adding an item to this array is like incrementing a binary number;
- * positional values for set bits correspond to sublist lengths.
- */
-void *llist_mergesort(void *list,
-		      void *(*get_next_fn)(const void *),
-		      void (*set_next_fn)(void *, void *),
-		      int (*compare_fn)(const void *, const void *))
-{
-	void *ranks[bitsizeof(void *)];
-	size_t n = 0;
-	int i;
-
-	while (list) {
-		void *next = get_next_fn(list);
-		if (next)
-			set_next_fn(list, NULL);
-		for (i = 0; n & ((size_t)1 << i); i++)
-			list = llist_merge(ranks[i], list, get_next_fn,
-					   set_next_fn, compare_fn);
-		n++;
-		ranks[i] = list;
-		list = next;
-	}
-
-	for (i = 0; n; i++, n >>= 1) {
-		if (!(n & 1))
-			continue;
-		if (list)
-			list = llist_merge(ranks[i], list, get_next_fn,
-					   set_next_fn, compare_fn);
-		else
-			list = ranks[i];
-	}
-	return list;
-}
diff --git a/mergesort.h b/mergesort.h
index 644cff1..7c36f08 100644
--- a/mergesort.h
+++ b/mergesort.h
@@ -1,17 +1,105 @@
 #ifndef MERGESORT_H
 #define MERGESORT_H
 
+/* Combine two sorted lists.  Take from `list` on equality. */
+#define DEFINE_LIST_MERGE_INTERNAL(name, type)				\
+static type *name##__merge(type *list, type *other,			\
+			   int (*compare_fn)(const type *, const type *))\
+{									\
+	type *result = list, *tail;					\
+	int prefer_list = compare_fn(list, other) <= 0;			\
+									\
+	if (!prefer_list) {						\
+		result = other;						\
+		SWAP(list, other);					\
+	}								\
+	for (;;) {							\
+		do {							\
+			tail = list;					\
+			list = name##__get_next(list);			\
+			if (!list) {					\
+				name##__set_next(tail, other);		\
+				return result;				\
+			}						\
+		} while (compare_fn(list, other) < prefer_list);	\
+		name##__set_next(tail, other);				\
+		prefer_list ^= 1;					\
+		SWAP(list, other);					\
+	}								\
+}
+
 /*
- * Sort linked list in place.
- * - get_next_fn() returns the next element given an element of a linked list.
- * - set_next_fn() takes two elements A and B, and makes B the "next" element
- *   of A on the list.
- * - compare_fn() takes two elements A and B, and returns negative, 0, positive
- *   as the same sign as "subtracting" B from A.
+ * Perform an iterative mergesort using an array of sublists.
+ *
+ * n is the number of items.
+ * ranks[i] is undefined if n & 2^i == 0, and assumed empty.
+ * ranks[i] contains a sublist of length 2^i otherwise.
+ *
+ * The number of bits in a void pointer limits the number of objects
+ * that can be created, and thus the number of array elements necessary
+ * to be able to sort any valid list.
+ *
+ * Adding an item to this array is like incrementing a binary number;
+ * positional values for set bits correspond to sublist lengths.
  */
-void *llist_mergesort(void *list,
-		      void *(*get_next_fn)(const void *),
-		      void (*set_next_fn)(void *, void *),
-		      int (*compare_fn)(const void *, const void *));
+#define DEFINE_LIST_SORT_INTERNAL(scope, name, type)			\
+scope void name(type **listp,						\
+		int (*compare_fn)(const type *, const type *))		\
+{									\
+	type *list = *listp;						\
+	type *ranks[bitsizeof(type *)];					\
+	size_t n = 0;							\
+									\
+	if (!list)							\
+		return;							\
+									\
+	for (;;) {							\
+		int i;							\
+		size_t m;						\
+		type *next = name##__get_next(list);			\
+		if (next)						\
+			name##__set_next(list, NULL);			\
+		for (i = 0, m = n;; i++, m >>= 1) {			\
+			if (m & 1) {					\
+				list = name##__merge(ranks[i], list,	\
+						    compare_fn);	\
+			} else if (next) {				\
+				break;					\
+			} else if (!m) {				\
+				*listp = list;				\
+				return;					\
+			}						\
+		}							\
+		n++;							\
+		ranks[i] = list;					\
+		list = next;						\
+	}								\
+}
+
+#define DECLARE_LIST_SORT(scope, name, type)			\
+scope void name(type **listp,					\
+		int (*compare_fn)(const type *, const type *))
+
+#define DEFINE_LIST_SORT_DEBUG(scope, name, type, next_member,	\
+			       on_get_next, on_set_next)	\
+								\
+static inline type *name##__get_next(const type *elem)		\
+{								\
+	on_get_next;						\
+	return elem->next_member;				\
+}								\
+								\
+static inline void name##__set_next(type *elem, type *next)	\
+{								\
+	on_set_next;						\
+	elem->next_member = next;				\
+}								\
+								\
+DEFINE_LIST_MERGE_INTERNAL(name, type)				\
+DEFINE_LIST_SORT_INTERNAL(scope, name, type)			\
+DECLARE_LIST_SORT(scope, name, type)
+
+#define DEFINE_LIST_SORT(scope, name, type, next_member) \
+DEFINE_LIST_SORT_DEBUG(scope, name, type, next_member, (void)0, (void)0)
 
 #endif
diff --git a/midx.c b/midx.c
index 5f0dd38..c27d0e5 100644
--- a/midx.c
+++ b/midx.c
@@ -577,6 +577,78 @@
 	entry->preferred = !!preferred;
 }
 
+struct midx_fanout {
+	struct pack_midx_entry *entries;
+	uint32_t nr;
+	uint32_t alloc;
+};
+
+static void midx_fanout_grow(struct midx_fanout *fanout, uint32_t nr)
+{
+	ALLOC_GROW(fanout->entries, nr, fanout->alloc);
+}
+
+static void midx_fanout_sort(struct midx_fanout *fanout)
+{
+	QSORT(fanout->entries, fanout->nr, midx_oid_compare);
+}
+
+static void midx_fanout_add_midx_fanout(struct midx_fanout *fanout,
+					struct multi_pack_index *m,
+					uint32_t cur_fanout,
+					int preferred_pack)
+{
+	uint32_t start = 0, end;
+	uint32_t cur_object;
+
+	if (cur_fanout)
+		start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
+	end = ntohl(m->chunk_oid_fanout[cur_fanout]);
+
+	for (cur_object = start; cur_object < end; cur_object++) {
+		if ((preferred_pack > -1) &&
+		    (preferred_pack == nth_midxed_pack_int_id(m, cur_object))) {
+			/*
+			 * Objects from preferred packs are added
+			 * separately.
+			 */
+			continue;
+		}
+
+		midx_fanout_grow(fanout, fanout->nr + 1);
+		nth_midxed_pack_midx_entry(m,
+					   &fanout->entries[fanout->nr],
+					   cur_object);
+		fanout->entries[fanout->nr].preferred = 0;
+		fanout->nr++;
+	}
+}
+
+static void midx_fanout_add_pack_fanout(struct midx_fanout *fanout,
+					struct pack_info *info,
+					uint32_t cur_pack,
+					int preferred,
+					uint32_t cur_fanout)
+{
+	struct packed_git *pack = info[cur_pack].p;
+	uint32_t start = 0, end;
+	uint32_t cur_object;
+
+	if (cur_fanout)
+		start = get_pack_fanout(pack, cur_fanout - 1);
+	end = get_pack_fanout(pack, cur_fanout);
+
+	for (cur_object = start; cur_object < end; cur_object++) {
+		midx_fanout_grow(fanout, fanout->nr + 1);
+		fill_pack_entry(cur_pack,
+				info[cur_pack].p,
+				cur_object,
+				&fanout->entries[fanout->nr],
+				preferred);
+		fanout->nr++;
+	}
+}
+
 /*
  * It is possible to artificially get into a state where there are many
  * duplicate copies of objects. That can create high memory pressure if
@@ -595,8 +667,8 @@
 						  int preferred_pack)
 {
 	uint32_t cur_fanout, cur_pack, cur_object;
-	uint32_t alloc_fanout, alloc_objects, total_objects = 0;
-	struct pack_midx_entry *entries_by_fanout = NULL;
+	uint32_t alloc_objects, total_objects = 0;
+	struct midx_fanout fanout = { 0 };
 	struct pack_midx_entry *deduplicated_entries = NULL;
 	uint32_t start_pack = m ? m->num_packs : 0;
 
@@ -608,74 +680,51 @@
 	 * slices to be evenly distributed, with some noise. Hence,
 	 * allocate slightly more than one 256th.
 	 */
-	alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16;
+	alloc_objects = fanout.alloc = total_objects > 3200 ? total_objects / 200 : 16;
 
-	ALLOC_ARRAY(entries_by_fanout, alloc_fanout);
+	ALLOC_ARRAY(fanout.entries, fanout.alloc);
 	ALLOC_ARRAY(deduplicated_entries, alloc_objects);
 	*nr_objects = 0;
 
 	for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) {
-		uint32_t nr_fanout = 0;
+		fanout.nr = 0;
 
-		if (m) {
-			uint32_t start = 0, end;
-
-			if (cur_fanout)
-				start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
-			end = ntohl(m->chunk_oid_fanout[cur_fanout]);
-
-			for (cur_object = start; cur_object < end; cur_object++) {
-				ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
-				nth_midxed_pack_midx_entry(m,
-							   &entries_by_fanout[nr_fanout],
-							   cur_object);
-				if (nth_midxed_pack_int_id(m, cur_object) == preferred_pack)
-					entries_by_fanout[nr_fanout].preferred = 1;
-				else
-					entries_by_fanout[nr_fanout].preferred = 0;
-				nr_fanout++;
-			}
-		}
+		if (m)
+			midx_fanout_add_midx_fanout(&fanout, m, cur_fanout,
+						    preferred_pack);
 
 		for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) {
-			uint32_t start = 0, end;
 			int preferred = cur_pack == preferred_pack;
-
-			if (cur_fanout)
-				start = get_pack_fanout(info[cur_pack].p, cur_fanout - 1);
-			end = get_pack_fanout(info[cur_pack].p, cur_fanout);
-
-			for (cur_object = start; cur_object < end; cur_object++) {
-				ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
-				fill_pack_entry(cur_pack,
-						info[cur_pack].p,
-						cur_object,
-						&entries_by_fanout[nr_fanout],
-						preferred);
-				nr_fanout++;
-			}
+			midx_fanout_add_pack_fanout(&fanout,
+						    info, cur_pack,
+						    preferred, cur_fanout);
 		}
 
-		QSORT(entries_by_fanout, nr_fanout, midx_oid_compare);
+		if (-1 < preferred_pack && preferred_pack < start_pack)
+			midx_fanout_add_pack_fanout(&fanout, info,
+						    preferred_pack, 1,
+						    cur_fanout);
+
+		midx_fanout_sort(&fanout);
 
 		/*
 		 * The batch is now sorted by OID and then mtime (descending).
 		 * Take only the first duplicate.
 		 */
-		for (cur_object = 0; cur_object < nr_fanout; cur_object++) {
-			if (cur_object && oideq(&entries_by_fanout[cur_object - 1].oid,
-						&entries_by_fanout[cur_object].oid))
+		for (cur_object = 0; cur_object < fanout.nr; cur_object++) {
+			if (cur_object && oideq(&fanout.entries[cur_object - 1].oid,
+						&fanout.entries[cur_object].oid))
 				continue;
 
 			ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects);
 			memcpy(&deduplicated_entries[*nr_objects],
-			       &entries_by_fanout[cur_object],
+			       &fanout.entries[cur_object],
 			       sizeof(struct pack_midx_entry));
 			(*nr_objects)++;
 		}
 	}
 
-	free(entries_by_fanout);
+	free(fanout.entries);
 	return deduplicated_entries;
 }
 
@@ -1053,40 +1102,37 @@
 	return cb.commits;
 }
 
-static int write_midx_bitmap(char *midx_name, unsigned char *midx_hash,
-			     struct write_midx_context *ctx,
-			     const char *refs_snapshot,
+static int write_midx_bitmap(const char *midx_name,
+			     const unsigned char *midx_hash,
+			     struct packing_data *pdata,
+			     struct commit **commits,
+			     uint32_t commits_nr,
+			     uint32_t *pack_order,
 			     unsigned flags)
 {
-	struct packing_data pdata;
-	struct pack_idx_entry **index;
-	struct commit **commits = NULL;
-	uint32_t i, commits_nr;
+	int ret, i;
 	uint16_t options = 0;
-	char *bitmap_name = xstrfmt("%s-%s.bitmap", midx_name, hash_to_hex(midx_hash));
-	int ret;
-
-	if (!ctx->entries_nr)
-		BUG("cannot write a bitmap without any objects");
+	struct pack_idx_entry **index;
+	char *bitmap_name = xstrfmt("%s-%s.bitmap", midx_name,
+					hash_to_hex(midx_hash));
 
 	if (flags & MIDX_WRITE_BITMAP_HASH_CACHE)
 		options |= BITMAP_OPT_HASH_CACHE;
 
-	prepare_midx_packing_data(&pdata, ctx);
-
-	commits = find_commits_for_midx_bitmap(&commits_nr, refs_snapshot, ctx);
+	if (flags & MIDX_WRITE_BITMAP_LOOKUP_TABLE)
+		options |= BITMAP_OPT_LOOKUP_TABLE;
 
 	/*
 	 * Build the MIDX-order index based on pdata.objects (which is already
 	 * in MIDX order; c.f., 'midx_pack_order_cmp()' for the definition of
 	 * this order).
 	 */
-	ALLOC_ARRAY(index, pdata.nr_objects);
-	for (i = 0; i < pdata.nr_objects; i++)
-		index[i] = &pdata.objects[i].idx;
+	ALLOC_ARRAY(index, pdata->nr_objects);
+	for (i = 0; i < pdata->nr_objects; i++)
+		index[i] = &pdata->objects[i].idx;
 
 	bitmap_writer_show_progress(flags & MIDX_PROGRESS);
-	bitmap_writer_build_type_index(&pdata, index, pdata.nr_objects);
+	bitmap_writer_build_type_index(pdata, index, pdata->nr_objects);
 
 	/*
 	 * bitmap_writer_finish expects objects in lex order, but pack_order
@@ -1101,16 +1147,16 @@
 	 * happens between bitmap_writer_build_type_index() and
 	 * bitmap_writer_finish().
 	 */
-	for (i = 0; i < pdata.nr_objects; i++)
-		index[ctx->pack_order[i]] = &pdata.objects[i].idx;
+	for (i = 0; i < pdata->nr_objects; i++)
+		index[pack_order[i]] = &pdata->objects[i].idx;
 
 	bitmap_writer_select_commits(commits, commits_nr, -1);
-	ret = bitmap_writer_build(&pdata);
+	ret = bitmap_writer_build(pdata);
 	if (ret < 0)
 		goto cleanup;
 
 	bitmap_writer_set_checksum(midx_hash);
-	bitmap_writer_finish(index, pdata.nr_objects, bitmap_name, options);
+	bitmap_writer_finish(index, pdata->nr_objects, bitmap_name, options);
 
 cleanup:
 	free(index);
@@ -1443,14 +1489,40 @@
 	if (flags & MIDX_WRITE_REV_INDEX &&
 	    git_env_bool("GIT_TEST_MIDX_WRITE_REV", 0))
 		write_midx_reverse_index(midx_name.buf, midx_hash, &ctx);
+
 	if (flags & MIDX_WRITE_BITMAP) {
-		if (write_midx_bitmap(midx_name.buf, midx_hash, &ctx,
-				      refs_snapshot, flags) < 0) {
+		struct packing_data pdata;
+		struct commit **commits;
+		uint32_t commits_nr;
+
+		if (!ctx.entries_nr)
+			BUG("cannot write a bitmap without any objects");
+
+		prepare_midx_packing_data(&pdata, &ctx);
+
+		commits = find_commits_for_midx_bitmap(&commits_nr, refs_snapshot, &ctx);
+
+		/*
+		 * The previous steps translated the information from
+		 * 'entries' into information suitable for constructing
+		 * bitmaps. We no longer need that array, so clear it to
+		 * reduce memory pressure.
+		 */
+		FREE_AND_NULL(ctx.entries);
+		ctx.entries_nr = 0;
+
+		if (write_midx_bitmap(midx_name.buf, midx_hash, &pdata,
+				      commits, commits_nr, ctx.pack_order,
+				      flags) < 0) {
 			error(_("could not write multi-pack bitmap"));
 			result = 1;
 			goto cleanup;
 		}
 	}
+	/*
+	 * NOTE: Do not use ctx.entries beyond this point, since it might
+	 * have been freed in the previous if block.
+	 */
 
 	if (ctx.m)
 		close_object_store(the_repository->objects);
diff --git a/midx.h b/midx.h
index 22e8e53..5578cd7 100644
--- a/midx.h
+++ b/midx.h
@@ -47,6 +47,7 @@
 #define MIDX_WRITE_REV_INDEX (1 << 1)
 #define MIDX_WRITE_BITMAP (1 << 2)
 #define MIDX_WRITE_BITMAP_HASH_CACHE (1 << 3)
+#define MIDX_WRITE_BITMAP_LOOKUP_TABLE (1 << 4)
 
 const unsigned char *get_midx_checksum(struct multi_pack_index *m);
 void get_midx_filename(struct strbuf *out, const char *object_dir);
diff --git a/name-hash.c b/name-hash.c
index 7487d33..cd009c7 100644
--- a/name-hash.c
+++ b/name-hash.c
@@ -18,7 +18,7 @@
 	char name[FLEX_ARRAY];
 };
 
-static int dir_entry_cmp(const void *unused_cmp_data,
+static int dir_entry_cmp(const void *cmp_data UNUSED,
 			 const struct hashmap_entry *eptr,
 			 const struct hashmap_entry *entry_or_key,
 			 const void *keydata)
@@ -120,7 +120,7 @@
 		add_dir_entry(istate, ce);
 }
 
-static int cache_entry_cmp(const void *unused_cmp_data,
+static int cache_entry_cmp(const void *cmp_data UNUSED,
 			   const struct hashmap_entry *eptr,
 			   const struct hashmap_entry *entry_or_key,
 			   const void *remove)
diff --git a/negotiator/default.c b/negotiator/default.c
index 434189a..b7e79fe 100644
--- a/negotiator/default.c
+++ b/negotiator/default.c
@@ -36,7 +36,8 @@
 }
 
 static int clear_marks(const char *refname, const struct object_id *oid,
-		       int flag, void *cb_data)
+		       int flag UNUSED,
+		       void *cb_data UNUSED)
 {
 	struct object *o = deref_tag(the_repository, parse_object(the_repository, oid), refname, 0);
 
diff --git a/negotiator/skipping.c b/negotiator/skipping.c
index 1236e79..c4398f5 100644
--- a/negotiator/skipping.c
+++ b/negotiator/skipping.c
@@ -72,7 +72,8 @@
 }
 
 static int clear_marks(const char *refname, const struct object_id *oid,
-		       int flag, void *cb_data)
+		       int flag UNUSED,
+		       void *cb_data UNUSED)
 {
 	struct object *o = deref_tag(the_repository, parse_object(the_repository, oid), refname, 0);
 
diff --git a/notes.c b/notes.c
index 7452e71..f2805d5 100644
--- a/notes.c
+++ b/notes.c
@@ -924,8 +924,9 @@
 	return ret;
 }
 
-static int string_list_add_one_ref(const char *refname, const struct object_id *oid,
-				   int flag, void *cb)
+static int string_list_add_one_ref(const char *refname,
+				   const struct object_id *oid UNUSED,
+				   int flag UNUSED, void *cb)
 {
 	struct string_list *refs = cb;
 	if (!unsorted_string_list_has_string(refs, refname))
@@ -1005,6 +1006,7 @@
 
 	if (!notes_ref)
 		notes_ref = default_notes_ref();
+	update_ref_namespace(NAMESPACE_NOTES, xstrdup(notes_ref));
 
 	if (!combine_notes)
 		combine_notes = combine_notes_concatenate;
diff --git a/object-file.c b/object-file.c
index 6c8e3b1..5b270f0 100644
--- a/object-file.c
+++ b/object-file.c
@@ -1951,6 +1951,96 @@
 	return fd;
 }
 
+/**
+ * Common steps for loose object writers to start writing loose
+ * objects:
+ *
+ * - Create tmpfile for the loose object.
+ * - Setup zlib stream for compression.
+ * - Start to feed header to zlib stream.
+ *
+ * Returns a "fd", which should later be provided to
+ * end_loose_object_common().
+ */
+static int start_loose_object_common(struct strbuf *tmp_file,
+				     const char *filename, unsigned flags,
+				     git_zstream *stream,
+				     unsigned char *buf, size_t buflen,
+				     git_hash_ctx *c,
+				     char *hdr, int hdrlen)
+{
+	int fd;
+
+	fd = create_tmpfile(tmp_file, filename);
+	if (fd < 0) {
+		if (flags & HASH_SILENT)
+			return -1;
+		else if (errno == EACCES)
+			return error(_("insufficient permission for adding "
+				       "an object to repository database %s"),
+				     get_object_directory());
+		else
+			return error_errno(
+				_("unable to create temporary file"));
+	}
+
+	/*  Setup zlib stream for compression */
+	git_deflate_init(stream, zlib_compression_level);
+	stream->next_out = buf;
+	stream->avail_out = buflen;
+	the_hash_algo->init_fn(c);
+
+	/*  Start to feed header to zlib stream */
+	stream->next_in = (unsigned char *)hdr;
+	stream->avail_in = hdrlen;
+	while (git_deflate(stream, 0) == Z_OK)
+		; /* nothing */
+	the_hash_algo->update_fn(c, hdr, hdrlen);
+
+	return fd;
+}
+
+/**
+ * Common steps for the inner git_deflate() loop for writing loose
+ * objects. Returns what git_deflate() returns.
+ */
+static int write_loose_object_common(git_hash_ctx *c,
+				     git_zstream *stream, const int flush,
+				     unsigned char *in0, const int fd,
+				     unsigned char *compressed,
+				     const size_t compressed_len)
+{
+	int ret;
+
+	ret = git_deflate(stream, flush ? Z_FINISH : 0);
+	the_hash_algo->update_fn(c, in0, stream->next_in - in0);
+	if (write_buffer(fd, compressed, stream->next_out - compressed) < 0)
+		die(_("unable to write loose object file"));
+	stream->next_out = compressed;
+	stream->avail_out = compressed_len;
+
+	return ret;
+}
+
+/**
+ * Common steps for loose object writers to end writing loose objects:
+ *
+ * - End the compression of zlib stream.
+ * - Get the calculated oid to "oid".
+ */
+static int end_loose_object_common(git_hash_ctx *c, git_zstream *stream,
+				   struct object_id *oid)
+{
+	int ret;
+
+	ret = git_deflate_end_gently(stream);
+	if (ret != Z_OK)
+		return ret;
+	the_hash_algo->final_oid_fn(oid, c);
+
+	return Z_OK;
+}
+
 static int write_loose_object(const struct object_id *oid, char *hdr,
 			      int hdrlen, const void *buf, unsigned long len,
 			      time_t mtime, unsigned flags)
@@ -1968,50 +2058,29 @@
 
 	loose_object_path(the_repository, &filename, oid);
 
-	fd = create_tmpfile(&tmp_file, filename.buf);
-	if (fd < 0) {
-		if (flags & HASH_SILENT)
-			return -1;
-		else if (errno == EACCES)
-			return error(_("insufficient permission for adding an object to repository database %s"), get_object_directory());
-		else
-			return error_errno(_("unable to create temporary file"));
-	}
-
-	/* Set it up */
-	git_deflate_init(&stream, zlib_compression_level);
-	stream.next_out = compressed;
-	stream.avail_out = sizeof(compressed);
-	the_hash_algo->init_fn(&c);
-
-	/* First header.. */
-	stream.next_in = (unsigned char *)hdr;
-	stream.avail_in = hdrlen;
-	while (git_deflate(&stream, 0) == Z_OK)
-		; /* nothing */
-	the_hash_algo->update_fn(&c, hdr, hdrlen);
+	fd = start_loose_object_common(&tmp_file, filename.buf, flags,
+				       &stream, compressed, sizeof(compressed),
+				       &c, hdr, hdrlen);
+	if (fd < 0)
+		return -1;
 
 	/* Then the data itself.. */
 	stream.next_in = (void *)buf;
 	stream.avail_in = len;
 	do {
 		unsigned char *in0 = stream.next_in;
-		ret = git_deflate(&stream, Z_FINISH);
-		the_hash_algo->update_fn(&c, in0, stream.next_in - in0);
-		if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
-			die(_("unable to write loose object file"));
-		stream.next_out = compressed;
-		stream.avail_out = sizeof(compressed);
+
+		ret = write_loose_object_common(&c, &stream, 1, in0, fd,
+						compressed, sizeof(compressed));
 	} while (ret == Z_OK);
 
 	if (ret != Z_STREAM_END)
 		die(_("unable to deflate new object %s (%d)"), oid_to_hex(oid),
 		    ret);
-	ret = git_deflate_end_gently(&stream);
+	ret = end_loose_object_common(&c, &stream, &parano_oid);
 	if (ret != Z_OK)
 		die(_("deflateEnd on object %s failed (%d)"), oid_to_hex(oid),
 		    ret);
-	the_hash_algo->final_oid_fn(&parano_oid, &c);
 	if (!oideq(oid, &parano_oid))
 		die(_("confused by unstable object source data for %s"),
 		    oid_to_hex(oid));
@@ -2050,6 +2119,110 @@
 	return 1;
 }
 
+int stream_loose_object(struct input_stream *in_stream, size_t len,
+			struct object_id *oid)
+{
+	int fd, ret, err = 0, flush = 0;
+	unsigned char compressed[4096];
+	git_zstream stream;
+	git_hash_ctx c;
+	struct strbuf tmp_file = STRBUF_INIT;
+	struct strbuf filename = STRBUF_INIT;
+	int dirlen;
+	char hdr[MAX_HEADER_LEN];
+	int hdrlen;
+
+	if (batch_fsync_enabled(FSYNC_COMPONENT_LOOSE_OBJECT))
+		prepare_loose_object_bulk_checkin();
+
+	/* Since oid is not determined, save tmp file to odb path. */
+	strbuf_addf(&filename, "%s/", get_object_directory());
+	hdrlen = format_object_header(hdr, sizeof(hdr), OBJ_BLOB, len);
+
+	/*
+	 * Common steps for write_loose_object and stream_loose_object to
+	 * start writing loose objects:
+	 *
+	 *  - Create tmpfile for the loose object.
+	 *  - Setup zlib stream for compression.
+	 *  - Start to feed header to zlib stream.
+	 */
+	fd = start_loose_object_common(&tmp_file, filename.buf, 0,
+				       &stream, compressed, sizeof(compressed),
+				       &c, hdr, hdrlen);
+	if (fd < 0) {
+		err = -1;
+		goto cleanup;
+	}
+
+	/* Then the data itself.. */
+	do {
+		unsigned char *in0 = stream.next_in;
+
+		if (!stream.avail_in && !in_stream->is_finished) {
+			const void *in = in_stream->read(in_stream, &stream.avail_in);
+			stream.next_in = (void *)in;
+			in0 = (unsigned char *)in;
+			/* All data has been read. */
+			if (in_stream->is_finished)
+				flush = 1;
+		}
+		ret = write_loose_object_common(&c, &stream, flush, in0, fd,
+						compressed, sizeof(compressed));
+		/*
+		 * Unlike write_loose_object(), we do not have the entire
+		 * buffer. If we get Z_BUF_ERROR due to too few input bytes,
+		 * then we'll replenish them in the next input_stream->read()
+		 * call when we loop.
+		 */
+	} while (ret == Z_OK || ret == Z_BUF_ERROR);
+
+	if (stream.total_in != len + hdrlen)
+		die(_("write stream object %ld != %"PRIuMAX), stream.total_in,
+		    (uintmax_t)len + hdrlen);
+
+	/*
+	 * Common steps for write_loose_object and stream_loose_object to
+	 * end writing loose oject:
+	 *
+	 *  - End the compression of zlib stream.
+	 *  - Get the calculated oid.
+	 */
+	if (ret != Z_STREAM_END)
+		die(_("unable to stream deflate new object (%d)"), ret);
+	ret = end_loose_object_common(&c, &stream, oid);
+	if (ret != Z_OK)
+		die(_("deflateEnd on stream object failed (%d)"), ret);
+	close_loose_object(fd, tmp_file.buf);
+
+	if (freshen_packed_object(oid) || freshen_loose_object(oid)) {
+		unlink_or_warn(tmp_file.buf);
+		goto cleanup;
+	}
+
+	loose_object_path(the_repository, &filename, oid);
+
+	/* We finally know the object path, and create the missing dir. */
+	dirlen = directory_size(filename.buf);
+	if (dirlen) {
+		struct strbuf dir = STRBUF_INIT;
+		strbuf_add(&dir, filename.buf, dirlen);
+
+		if (mkdir_in_gitdir(dir.buf) && errno != EEXIST) {
+			err = error_errno(_("unable to create directory %s"), dir.buf);
+			strbuf_release(&dir);
+			goto cleanup;
+		}
+		strbuf_release(&dir);
+	}
+
+	err = finalize_object_file(tmp_file.buf, filename.buf);
+cleanup:
+	strbuf_release(&tmp_file);
+	strbuf_release(&filename);
+	return err;
+}
+
 int write_object_file_flags(const void *buf, unsigned long len,
 			    enum object_type type, struct object_id *oid,
 			    unsigned flags)
diff --git a/object-name.c b/object-name.c
index 4d27465..2dd1a0f 100644
--- a/object-name.c
+++ b/object-name.c
@@ -1306,7 +1306,8 @@
 };
 
 static int handle_one_ref(const char *path, const struct object_id *oid,
-			  int flag, void *cb_data)
+			  int flag UNUSED,
+			  void *cb_data)
 {
 	struct handle_one_ref_cb *cb = cb_data;
 	struct commit_list **list = cb->list;
@@ -1384,8 +1385,11 @@
 	struct strbuf *sb;
 };
 
-static int grab_nth_branch_switch(struct object_id *ooid, struct object_id *noid,
-				  const char *email, timestamp_t timestamp, int tz,
+static int grab_nth_branch_switch(struct object_id *ooid UNUSED,
+				  struct object_id *noid UNUSED,
+				  const char *email UNUSED,
+				  timestamp_t timestamp UNUSED,
+				  int tz UNUSED,
 				  const char *message, void *cb_data)
 {
 	struct grab_nth_branch_switch_cbdata *cb = cb_data;
diff --git a/object-store.h b/object-store.h
index 539ea43..1be57ab 100644
--- a/object-store.h
+++ b/object-store.h
@@ -46,6 +46,12 @@
 	char *path;
 };
 
+struct input_stream {
+	const void *(*read)(struct input_stream *, unsigned long *len);
+	void *data;
+	int is_finished;
+};
+
 KHASH_INIT(odb_path_map, const char * /* key: odb_path */,
 	struct object_directory *, 1, fspathhash, fspatheq)
 
@@ -135,7 +141,7 @@
 
 struct multi_pack_index;
 
-static inline int pack_map_entry_cmp(const void *unused_cmp_data,
+static inline int pack_map_entry_cmp(const void *cmp_data UNUSED,
 				     const struct hashmap_entry *entry,
 				     const struct hashmap_entry *entry2,
 				     const void *keydata)
@@ -269,6 +275,8 @@
 int write_object_file_literally(const void *buf, unsigned long len,
 				const char *type, struct object_id *oid,
 				unsigned flags);
+int stream_loose_object(struct input_stream *in_stream, size_t len,
+			struct object_id *oid);
 
 /*
  * Add an object file to the in-memory object store, without writing it
diff --git a/object.c b/object.c
index 588b815..2e4589b 100644
--- a/object.c
+++ b/object.c
@@ -263,8 +263,11 @@
 	die(_("unable to parse object: %s"), name ? name : oid_to_hex(oid));
 }
 
-struct object *parse_object(struct repository *r, const struct object_id *oid)
+struct object *parse_object_with_flags(struct repository *r,
+				       const struct object_id *oid,
+				       enum parse_object_flags flags)
 {
+	int skip_hash = !!(flags & PARSE_OBJECT_SKIP_HASH_CHECK);
 	unsigned long size;
 	enum object_type type;
 	int eaten;
@@ -276,10 +279,16 @@
 	if (obj && obj->parsed)
 		return obj;
 
+	if (skip_hash) {
+		struct commit *commit = lookup_commit_in_graph(r, repl);
+		if (commit)
+			return &commit->object;
+	}
+
 	if ((obj && obj->type == OBJ_BLOB && repo_has_object_file(r, oid)) ||
 	    (!obj && repo_has_object_file(r, oid) &&
 	     oid_object_info(r, oid, NULL) == OBJ_BLOB)) {
-		if (stream_object_signature(r, repl) < 0) {
+		if (!skip_hash && stream_object_signature(r, repl) < 0) {
 			error(_("hash mismatch %s"), oid_to_hex(oid));
 			return NULL;
 		}
@@ -289,7 +298,8 @@
 
 	buffer = repo_read_object_file(r, oid, &type, &size);
 	if (buffer) {
-		if (check_object_signature(r, repl, buffer, size, type) < 0) {
+		if (!skip_hash &&
+		    check_object_signature(r, repl, buffer, size, type) < 0) {
 			free(buffer);
 			error(_("hash mismatch %s"), oid_to_hex(repl));
 			return NULL;
@@ -304,6 +314,11 @@
 	return NULL;
 }
 
+struct object *parse_object(struct repository *r, const struct object_id *oid)
+{
+	return parse_object_with_flags(r, oid, 0);
+}
+
 struct object_list *object_list_insert(struct object *item,
 				       struct object_list **list_p)
 {
diff --git a/object.h b/object.h
index a221946..31ebe11 100644
--- a/object.h
+++ b/object.h
@@ -59,7 +59,7 @@
 
 /*
  * object flag allocation:
- * revision.h:               0---------10         15             23------26
+ * revision.h:               0---------10         15             23------27
  * fetch-pack.c:             01    67
  * negotiator/default.c:       2--5
  * walker.c:                 0-2
@@ -128,7 +128,13 @@
  *
  * Returns NULL if the object is missing or corrupt.
  */
+enum parse_object_flags {
+	PARSE_OBJECT_SKIP_HASH_CHECK = 1 << 0,
+};
 struct object *parse_object(struct repository *r, const struct object_id *oid);
+struct object *parse_object_with_flags(struct repository *r,
+				       const struct object_id *oid,
+				       enum parse_object_flags flags);
 
 /*
  * Like parse_object, but will die() instead of returning NULL. If the
diff --git a/oidmap.c b/oidmap.c
index 286a04a..49965fe 100644
--- a/oidmap.c
+++ b/oidmap.c
@@ -1,7 +1,7 @@
 #include "cache.h"
 #include "oidmap.h"
 
-static int oidmap_neq(const void *hashmap_cmp_fn_data,
+static int oidmap_neq(const void *hashmap_cmp_fn_data UNUSED,
 		      const struct hashmap_entry *e1,
 		      const struct hashmap_entry *e2,
 		      const void *keydata)
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index c43375b..a213f5e 100644
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -649,21 +649,18 @@
 }
 
 static void write_selected_commits_v1(struct hashfile *f,
-				      struct pack_idx_entry **index,
-				      uint32_t index_nr)
+				      uint32_t *commit_positions,
+				      off_t *offsets)
 {
 	int i;
 
 	for (i = 0; i < writer.selected_nr; ++i) {
 		struct bitmapped_commit *stored = &writer.selected[i];
 
-		int commit_pos =
-			oid_pos(&stored->commit->object.oid, index, index_nr, oid_access);
+		if (offsets)
+			offsets[i] = hashfile_total(f);
 
-		if (commit_pos < 0)
-			BUG("trying to write commit not in index");
-
-		hashwrite_be32(f, commit_pos);
+		hashwrite_be32(f, commit_positions[i]);
 		hashwrite_u8(f, stored->xor_offset);
 		hashwrite_u8(f, stored->flags);
 
@@ -671,6 +668,79 @@
 	}
 }
 
+static int table_cmp(const void *_va, const void *_vb, void *_data)
+{
+	uint32_t *commit_positions = _data;
+	uint32_t a = commit_positions[*(uint32_t *)_va];
+	uint32_t b = commit_positions[*(uint32_t *)_vb];
+
+	if (a > b)
+		return 1;
+	else if (a < b)
+		return -1;
+
+	return 0;
+}
+
+static void write_lookup_table(struct hashfile *f,
+			       uint32_t *commit_positions,
+			       off_t *offsets)
+{
+	uint32_t i;
+	uint32_t *table, *table_inv;
+
+	ALLOC_ARRAY(table, writer.selected_nr);
+	ALLOC_ARRAY(table_inv, writer.selected_nr);
+
+	for (i = 0; i < writer.selected_nr; i++)
+		table[i] = i;
+
+	/*
+	 * At the end of this sort table[j] = i means that the i'th
+	 * bitmap corresponds to j'th bitmapped commit (among the selected
+	 * commits) in lex order of OIDs.
+	 */
+	QSORT_S(table, writer.selected_nr, table_cmp, commit_positions);
+
+	/* table_inv helps us discover that relationship (i'th bitmap
+	 * to j'th commit by j = table_inv[i])
+	 */
+	for (i = 0; i < writer.selected_nr; i++)
+		table_inv[table[i]] = i;
+
+	trace2_region_enter("pack-bitmap-write", "writing_lookup_table", the_repository);
+	for (i = 0; i < writer.selected_nr; i++) {
+		struct bitmapped_commit *selected = &writer.selected[table[i]];
+		uint32_t xor_offset = selected->xor_offset;
+		uint32_t xor_row;
+
+		if (xor_offset) {
+			/*
+			 * xor_index stores the index (in the bitmap entries)
+			 * of the corresponding xor bitmap. But we need to convert
+			 * this index into lookup table's index. So, table_inv[xor_index]
+			 * gives us the index position w.r.t. the lookup table.
+			 *
+			 * If "k = table[i] - xor_offset" then the xor base is the k'th
+			 * bitmap. `table_inv[k]` gives us the position of that bitmap
+			 * in the lookup table.
+			 */
+			uint32_t xor_index = table[i] - xor_offset;
+			xor_row = table_inv[xor_index];
+		} else {
+			xor_row = 0xffffffff;
+		}
+
+		hashwrite_be32(f, commit_positions[table[i]]);
+		hashwrite_be64(f, (uint64_t)offsets[table[i]]);
+		hashwrite_be32(f, xor_row);
+	}
+	trace2_region_leave("pack-bitmap-write", "writing_lookup_table", the_repository);
+
+	free(table);
+	free(table_inv);
+}
+
 static void write_hash_cache(struct hashfile *f,
 			     struct pack_idx_entry **index,
 			     uint32_t index_nr)
@@ -683,7 +753,7 @@
 	}
 }
 
-void bitmap_writer_set_checksum(unsigned char *sha1)
+void bitmap_writer_set_checksum(const unsigned char *sha1)
 {
 	hashcpy(writer.pack_checksum, sha1);
 }
@@ -697,6 +767,9 @@
 	static uint16_t flags = BITMAP_OPT_FULL_DAG;
 	struct strbuf tmp_file = STRBUF_INIT;
 	struct hashfile *f;
+	uint32_t *commit_positions = NULL;
+	off_t *offsets = NULL;
+	uint32_t i;
 
 	struct bitmap_disk_header header;
 
@@ -715,7 +788,26 @@
 	dump_bitmap(f, writer.trees);
 	dump_bitmap(f, writer.blobs);
 	dump_bitmap(f, writer.tags);
-	write_selected_commits_v1(f, index, index_nr);
+
+	if (options & BITMAP_OPT_LOOKUP_TABLE)
+		CALLOC_ARRAY(offsets, index_nr);
+
+	ALLOC_ARRAY(commit_positions, writer.selected_nr);
+
+	for (i = 0; i < writer.selected_nr; i++) {
+		struct bitmapped_commit *stored = &writer.selected[i];
+		int commit_pos = oid_pos(&stored->commit->object.oid, index, index_nr, oid_access);
+
+		if (commit_pos < 0)
+			BUG(_("trying to write commit not in index"));
+
+		commit_positions[i] = commit_pos;
+	}
+
+	write_selected_commits_v1(f, commit_positions, offsets);
+
+	if (options & BITMAP_OPT_LOOKUP_TABLE)
+		write_lookup_table(f, commit_positions, offsets);
 
 	if (options & BITMAP_OPT_HASH_CACHE)
 		write_hash_cache(f, index, index_nr);
@@ -730,4 +822,6 @@
 		die_errno("unable to rename temporary bitmap file to '%s'", filename);
 
 	strbuf_release(&tmp_file);
+	free(commit_positions);
+	free(offsets);
 }
diff --git a/pack-bitmap.c b/pack-bitmap.c
index 3613422..9a208ab 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "commit.h"
+#include "strbuf.h"
 #include "tag.h"
 #include "diff.h"
 #include "revision.h"
@@ -83,6 +84,12 @@
 	const unsigned char *checksum;
 
 	/*
+	 * If not NULL, this point into the commit table extension
+	 * (within the memory mapped region `map`).
+	 */
+	unsigned char *table_lookup;
+
+	/*
 	 * Extended index.
 	 *
 	 * When trying to perform bitmap operations with objects that are not
@@ -138,7 +145,7 @@
 		index->map_size - index->map_pos);
 
 	if (bitmap_size < 0) {
-		error("Failed to load bitmap index (corrupted?)");
+		error(_("failed to load bitmap index (corrupted?)"));
 		ewah_pool_free(b);
 		return NULL;
 	}
@@ -160,14 +167,14 @@
 	size_t header_size = sizeof(*header) - GIT_MAX_RAWSZ + the_hash_algo->rawsz;
 
 	if (index->map_size < header_size + the_hash_algo->rawsz)
-		return error("Corrupted bitmap index (too small)");
+		return error(_("corrupted bitmap index (too small)"));
 
 	if (memcmp(header->magic, BITMAP_IDX_SIGNATURE, sizeof(BITMAP_IDX_SIGNATURE)) != 0)
-		return error("Corrupted bitmap index file (wrong header)");
+		return error(_("corrupted bitmap index file (wrong header)"));
 
 	index->version = ntohs(header->version);
 	if (index->version != 1)
-		return error("Unsupported version for bitmap index file (%d)", index->version);
+		return error(_("unsupported version '%d' for bitmap index file"), index->version);
 
 	/* Parse known bitmap format options */
 	{
@@ -176,15 +183,25 @@
 		unsigned char *index_end = index->map + index->map_size - the_hash_algo->rawsz;
 
 		if ((flags & BITMAP_OPT_FULL_DAG) == 0)
-			return error("Unsupported options for bitmap index file "
+			BUG("unsupported options for bitmap index file "
 				"(Git requires BITMAP_OPT_FULL_DAG)");
 
 		if (flags & BITMAP_OPT_HASH_CACHE) {
 			if (cache_size > index_end - index->map - header_size)
-				return error("corrupted bitmap index file (too short to fit hash cache)");
+				return error(_("corrupted bitmap index file (too short to fit hash cache)"));
 			index->hashes = (void *)(index_end - cache_size);
 			index_end -= cache_size;
 		}
+
+		if (flags & BITMAP_OPT_LOOKUP_TABLE) {
+			size_t table_size = st_mult(ntohl(header->entry_count),
+						    BITMAP_LOOKUP_TABLE_TRIPLET_WIDTH);
+			if (table_size > index_end - index->map - header_size)
+				return error(_("corrupted bitmap index file (too short to fit lookup table)"));
+			if (git_env_bool("GIT_TEST_READ_COMMIT_TABLE", 1))
+				index->table_lookup = (void *)(index_end - table_size);
+			index_end -= table_size;
+		}
 	}
 
 	index->entry_count = ntohl(header->entry_count);
@@ -211,11 +228,13 @@
 
 	hash_pos = kh_put_oid_map(index->bitmaps, stored->oid, &ret);
 
-	/* a 0 return code means the insertion succeeded with no changes,
-	 * because the SHA1 already existed on the map. this is bad, there
-	 * shouldn't be duplicated commits in the index */
+	/*
+	 * A 0 return code means the insertion succeeded with no changes,
+	 * because the SHA1 already existed on the map. This is bad, there
+	 * shouldn't be duplicated commits in the index.
+	 */
 	if (ret == 0) {
-		error("Duplicate entry in bitmap index: %s", oid_to_hex(oid));
+		error(_("duplicate entry in bitmap index: '%s'"), oid_to_hex(oid));
 		return NULL;
 	}
 
@@ -259,14 +278,14 @@
 		struct object_id oid;
 
 		if (index->map_size - index->map_pos < 6)
-			return error("corrupt ewah bitmap: truncated header for entry %d", i);
+			return error(_("corrupt ewah bitmap: truncated header for entry %d"), i);
 
 		commit_idx_pos = read_be32(index->map, &index->map_pos);
 		xor_offset = read_u8(index->map, &index->map_pos);
 		flags = read_u8(index->map, &index->map_pos);
 
 		if (nth_bitmap_object_oid(index, &oid, commit_idx_pos) < 0)
-			return error("corrupt ewah bitmap: commit index %u out of range",
+			return error(_("corrupt ewah bitmap: commit index %u out of range"),
 				     (unsigned)commit_idx_pos);
 
 		bitmap = read_bitmap_1(index);
@@ -274,13 +293,13 @@
 			return -1;
 
 		if (xor_offset > MAX_XOR_OFFSET || xor_offset > i)
-			return error("Corrupted bitmap pack index");
+			return error(_("corrupted bitmap pack index"));
 
 		if (xor_offset > 0) {
 			xor_bitmap = recent_bitmaps[(i - xor_offset) % MAX_XOR_OFFSET];
 
 			if (!xor_bitmap)
-				return error("Invalid XOR offset in bitmap pack index");
+				return error(_("invalid XOR offset in bitmap pack index"));
 		}
 
 		recent_bitmaps[i % MAX_XOR_OFFSET] = store_bitmap(
@@ -313,17 +332,21 @@
 			      struct multi_pack_index *midx)
 {
 	struct stat st;
-	char *idx_name = midx_bitmap_filename(midx);
-	int fd = git_open(idx_name);
+	char *bitmap_name = midx_bitmap_filename(midx);
+	int fd = git_open(bitmap_name);
 	uint32_t i;
 	struct packed_git *preferred;
 
-	free(idx_name);
-
-	if (fd < 0)
+	if (fd < 0) {
+		if (errno != ENOENT)
+			warning_errno("cannot open '%s'", bitmap_name);
+		free(bitmap_name);
 		return -1;
+	}
+	free(bitmap_name);
 
 	if (fstat(fd, &st)) {
+		error_errno(_("cannot fstat bitmap file"));
 		close(fd);
 		return -1;
 	}
@@ -332,7 +355,7 @@
 		struct strbuf buf = STRBUF_INIT;
 		get_midx_filename(&buf, midx->object_dir);
 		/* ignore extra bitmap file; we can only handle one */
-		warning("ignoring extra bitmap file: %s", buf.buf);
+		warning(_("ignoring extra bitmap file: '%s'"), buf.buf);
 		close(fd);
 		strbuf_release(&buf);
 		return -1;
@@ -348,8 +371,10 @@
 	if (load_bitmap_header(bitmap_git) < 0)
 		goto cleanup;
 
-	if (!hasheq(get_midx_checksum(bitmap_git->midx), bitmap_git->checksum))
+	if (!hasheq(get_midx_checksum(bitmap_git->midx), bitmap_git->checksum)) {
+		error(_("checksum doesn't match in MIDX and bitmap"));
 		goto cleanup;
+	}
 
 	if (load_midx_revindex(bitmap_git->midx) < 0) {
 		warning(_("multi-pack bitmap is missing required reverse index"));
@@ -384,26 +409,31 @@
 {
 	int fd;
 	struct stat st;
-	char *idx_name;
+	char *bitmap_name;
 
 	if (open_pack_index(packfile))
 		return -1;
 
-	idx_name = pack_bitmap_filename(packfile);
-	fd = git_open(idx_name);
-	free(idx_name);
+	bitmap_name = pack_bitmap_filename(packfile);
+	fd = git_open(bitmap_name);
 
-	if (fd < 0)
+	if (fd < 0) {
+		if (errno != ENOENT)
+			warning_errno("cannot open '%s'", bitmap_name);
+		free(bitmap_name);
 		return -1;
+	}
+	free(bitmap_name);
 
 	if (fstat(fd, &st)) {
+		error_errno(_("cannot fstat bitmap file"));
 		close(fd);
 		return -1;
 	}
 
 	if (bitmap_git->pack || bitmap_git->midx) {
 		/* ignore extra bitmap file; we can only handle one */
-		warning("ignoring extra bitmap file: %s", packfile->pack_name);
+		warning(_("ignoring extra bitmap file: '%s'"), packfile->pack_name);
 		close(fd);
 		return -1;
 	}
@@ -470,7 +500,7 @@
 		!(bitmap_git->tags = read_bitmap_1(bitmap_git)))
 		goto failed;
 
-	if (load_bitmap_entries_v1(bitmap_git) < 0)
+	if (!bitmap_git->table_lookup && load_bitmap_entries_v1(bitmap_git) < 0)
 		goto failed;
 
 	return 0;
@@ -508,15 +538,16 @@
 static int open_midx_bitmap(struct repository *r,
 			    struct bitmap_index *bitmap_git)
 {
+	int ret = -1;
 	struct multi_pack_index *midx;
 
 	assert(!bitmap_git->map);
 
 	for (midx = get_multi_pack_index(r); midx; midx = midx->next) {
 		if (!open_midx_bitmap_1(bitmap_git, midx))
-			return 0;
+			ret = 0;
 	}
-	return -1;
+	return ret;
 }
 
 static int open_bitmap(struct repository *r,
@@ -557,13 +588,256 @@
 	struct bitmap *seen;
 };
 
+struct bitmap_lookup_table_triplet {
+	uint32_t commit_pos;
+	uint64_t offset;
+	uint32_t xor_row;
+};
+
+struct bitmap_lookup_table_xor_item {
+	struct object_id oid;
+	uint64_t offset;
+};
+
+/*
+ * Given a `triplet` struct pointer and pointer `p`, this
+ * function reads the triplet beginning at `p` into the struct.
+ * Note that this function assumes that there is enough memory
+ * left for filling the `triplet` struct from `p`.
+ */
+static int bitmap_lookup_table_get_triplet_by_pointer(struct bitmap_lookup_table_triplet *triplet,
+						      const unsigned char *p)
+{
+	if (!triplet)
+		return -1;
+
+	triplet->commit_pos = get_be32(p);
+	p += sizeof(uint32_t);
+	triplet->offset = get_be64(p);
+	p += sizeof(uint64_t);
+	triplet->xor_row = get_be32(p);
+	return 0;
+}
+
+/*
+ * This function gets the raw triplet from `row`'th row in the
+ * lookup table and fills that data to the `triplet`.
+ */
+static int bitmap_lookup_table_get_triplet(struct bitmap_index *bitmap_git,
+					   uint32_t pos,
+					   struct bitmap_lookup_table_triplet *triplet)
+{
+	unsigned char *p = NULL;
+	if (pos >= bitmap_git->entry_count)
+		return error(_("corrupt bitmap lookup table: triplet position out of index"));
+
+	p = bitmap_git->table_lookup + st_mult(pos, BITMAP_LOOKUP_TABLE_TRIPLET_WIDTH);
+
+	return bitmap_lookup_table_get_triplet_by_pointer(triplet, p);
+}
+
+/*
+ * Searches for a matching triplet. `commit_pos` is a pointer
+ * to the wanted commit position value. `table_entry` points to
+ * a triplet in lookup table. The first 4 bytes of each
+ * triplet (pointed by `table_entry`) are compared with `*commit_pos`.
+ */
+static int triplet_cmp(const void *commit_pos, const void *table_entry)
+{
+
+	uint32_t a = *(uint32_t *)commit_pos;
+	uint32_t b = get_be32(table_entry);
+	if (a > b)
+		return 1;
+	else if (a < b)
+		return -1;
+
+	return 0;
+}
+
+static uint32_t bitmap_bsearch_pos(struct bitmap_index *bitmap_git,
+			    struct object_id *oid,
+			    uint32_t *result)
+{
+	int found;
+
+	if (bitmap_is_midx(bitmap_git))
+		found = bsearch_midx(oid, bitmap_git->midx, result);
+	else
+		found = bsearch_pack(oid, bitmap_git->pack, result);
+
+	return found;
+}
+
+/*
+ * `bsearch_triplet_by_pos` function searches for the raw triplet
+ * having commit position same as `commit_pos` and fills `triplet`
+ * object from the raw triplet. Returns 1 on success and 0 on
+ * failure.
+ */
+static int bitmap_bsearch_triplet_by_pos(uint32_t commit_pos,
+				  struct bitmap_index *bitmap_git,
+				  struct bitmap_lookup_table_triplet *triplet)
+{
+	unsigned char *p = bsearch(&commit_pos, bitmap_git->table_lookup, bitmap_git->entry_count,
+				   BITMAP_LOOKUP_TABLE_TRIPLET_WIDTH, triplet_cmp);
+
+	if (!p)
+		return -1;
+
+	return bitmap_lookup_table_get_triplet_by_pointer(triplet, p);
+}
+
+static struct stored_bitmap *lazy_bitmap_for_commit(struct bitmap_index *bitmap_git,
+						    struct commit *commit)
+{
+	uint32_t commit_pos, xor_row;
+	uint64_t offset;
+	int flags;
+	struct bitmap_lookup_table_triplet triplet;
+	struct object_id *oid = &commit->object.oid;
+	struct ewah_bitmap *bitmap;
+	struct stored_bitmap *xor_bitmap = NULL;
+	const int bitmap_header_size = 6;
+	static struct bitmap_lookup_table_xor_item *xor_items = NULL;
+	static size_t xor_items_nr = 0, xor_items_alloc = 0;
+	static int is_corrupt = 0;
+	int xor_flags;
+	khiter_t hash_pos;
+	struct bitmap_lookup_table_xor_item *xor_item;
+
+	if (is_corrupt)
+		return NULL;
+
+	if (!bitmap_bsearch_pos(bitmap_git, oid, &commit_pos))
+		return NULL;
+
+	if (bitmap_bsearch_triplet_by_pos(commit_pos, bitmap_git, &triplet) < 0)
+		return NULL;
+
+	xor_items_nr = 0;
+	offset = triplet.offset;
+	xor_row = triplet.xor_row;
+
+	while (xor_row != 0xffffffff) {
+		ALLOC_GROW(xor_items, xor_items_nr + 1, xor_items_alloc);
+
+		if (xor_items_nr + 1 >= bitmap_git->entry_count) {
+			error(_("corrupt bitmap lookup table: xor chain exceed entry count"));
+			goto corrupt;
+		}
+
+		if (bitmap_lookup_table_get_triplet(bitmap_git, xor_row, &triplet) < 0)
+			goto corrupt;
+
+		xor_item = &xor_items[xor_items_nr];
+		xor_item->offset = triplet.offset;
+
+		if (nth_bitmap_object_oid(bitmap_git, &xor_item->oid, triplet.commit_pos) < 0) {
+			error(_("corrupt bitmap lookup table: commit index %u out of range"),
+				triplet.commit_pos);
+			goto corrupt;
+		}
+
+		hash_pos = kh_get_oid_map(bitmap_git->bitmaps, xor_item->oid);
+
+		/*
+		 * If desired bitmap is already stored, we don't need
+		 * to iterate further. Because we know that bitmaps
+		 * that are needed to be parsed to parse this bitmap
+		 * has already been stored. So, assign this stored bitmap
+		 * to the xor_bitmap.
+		 */
+		if (hash_pos < kh_end(bitmap_git->bitmaps) &&
+			(xor_bitmap = kh_value(bitmap_git->bitmaps, hash_pos)))
+			break;
+		xor_items_nr++;
+		xor_row = triplet.xor_row;
+	}
+
+	while (xor_items_nr) {
+		xor_item = &xor_items[xor_items_nr - 1];
+		bitmap_git->map_pos = xor_item->offset;
+		if (bitmap_git->map_size - bitmap_git->map_pos < bitmap_header_size) {
+			error(_("corrupt ewah bitmap: truncated header for bitmap of commit \"%s\""),
+				oid_to_hex(&xor_item->oid));
+			goto corrupt;
+		}
+
+		bitmap_git->map_pos += sizeof(uint32_t) + sizeof(uint8_t);
+		xor_flags = read_u8(bitmap_git->map, &bitmap_git->map_pos);
+		bitmap = read_bitmap_1(bitmap_git);
+
+		if (!bitmap)
+			goto corrupt;
+
+		xor_bitmap = store_bitmap(bitmap_git, bitmap, &xor_item->oid, xor_bitmap, xor_flags);
+		xor_items_nr--;
+	}
+
+	bitmap_git->map_pos = offset;
+	if (bitmap_git->map_size - bitmap_git->map_pos < bitmap_header_size) {
+		error(_("corrupt ewah bitmap: truncated header for bitmap of commit \"%s\""),
+			oid_to_hex(oid));
+		goto corrupt;
+	}
+
+	/*
+	 * Don't bother reading the commit's index position or its xor
+	 * offset:
+	 *
+	 *   - The commit's index position is irrelevant to us, since
+	 *     load_bitmap_entries_v1 only uses it to learn the object
+	 *     id which is used to compute the hashmap's key. We already
+	 *     have an object id, so no need to look it up again.
+	 *
+	 *   - The xor_offset is unusable for us, since it specifies how
+	 *     many entries previous to ours we should look at. This
+	 *     makes sense when reading the bitmaps sequentially (as in
+	 *     load_bitmap_entries_v1()), since we can keep track of
+	 *     each bitmap as we read them.
+	 *
+	 *     But it can't work for us, since the bitmap's don't have a
+	 *     fixed size. So we learn the position of the xor'd bitmap
+	 *     from the commit table (and resolve it to a bitmap in the
+	 *     above if-statement).
+	 *
+	 * Instead, we can skip ahead and immediately read the flags and
+	 * ewah bitmap.
+	 */
+	bitmap_git->map_pos += sizeof(uint32_t) + sizeof(uint8_t);
+	flags = read_u8(bitmap_git->map, &bitmap_git->map_pos);
+	bitmap = read_bitmap_1(bitmap_git);
+
+	if (!bitmap)
+		goto corrupt;
+
+	return store_bitmap(bitmap_git, bitmap, oid, xor_bitmap, flags);
+
+corrupt:
+	free(xor_items);
+	is_corrupt = 1;
+	return NULL;
+}
+
 struct ewah_bitmap *bitmap_for_commit(struct bitmap_index *bitmap_git,
 				      struct commit *commit)
 {
 	khiter_t hash_pos = kh_get_oid_map(bitmap_git->bitmaps,
 					   commit->object.oid);
-	if (hash_pos >= kh_end(bitmap_git->bitmaps))
-		return NULL;
+	if (hash_pos >= kh_end(bitmap_git->bitmaps)) {
+		struct stored_bitmap *bitmap = NULL;
+		if (!bitmap_git->table_lookup)
+			return NULL;
+
+		trace2_region_enter("pack-bitmap", "reading_lookup_table", the_repository);
+		/* NEEDSWORK: cache misses aren't recorded */
+		bitmap = lazy_bitmap_for_commit(bitmap_git, commit);
+		trace2_region_leave("pack-bitmap", "reading_lookup_table", the_repository);
+		if (!bitmap)
+			return NULL;
+		return lookup_stored_bitmap(bitmap);
+	}
 	return lookup_stored_bitmap(kh_value(bitmap_git->bitmaps, hash_pos));
 }
 
@@ -831,7 +1105,7 @@
 		revs->include_check_data = &incdata;
 
 		if (prepare_revision_walk(revs))
-			die("revision walk setup failed");
+			die(_("revision walk setup failed"));
 
 		show_data.bitmap_git = bitmap_git;
 		show_data.base = base;
@@ -1640,15 +1914,15 @@
 	}
 
 	if (bitmap_type == OBJ_NONE)
-		die("object %s not found in type bitmaps",
+		die(_("object '%s' not found in type bitmaps"),
 		    oid_to_hex(&obj->oid));
 
 	if (bitmaps_nr > 1)
-		die("object %s does not have a unique type",
+		die(_("object '%s' does not have a unique type"),
 		    oid_to_hex(&obj->oid));
 
 	if (bitmap_type != obj->type)
-		die("object %s: real type %s, expected: %s",
+		die(_("object '%s': real type '%s', expected: '%s'"),
 		    oid_to_hex(&obj->oid),
 		    type_name(obj->type),
 		    type_name(bitmap_type));
@@ -1662,7 +1936,7 @@
 
 	bitmap_pos = bitmap_position(tdata->bitmap_git, &object->oid);
 	if (bitmap_pos < 0)
-		die("Object not in bitmap: %s\n", oid_to_hex(&object->oid));
+		die(_("object not in bitmap: '%s'"), oid_to_hex(&object->oid));
 	test_bitmap_type(tdata, object, bitmap_pos);
 
 	bitmap_set(tdata->base, bitmap_pos);
@@ -1677,7 +1951,7 @@
 	bitmap_pos = bitmap_position(tdata->bitmap_git,
 				     &commit->object.oid);
 	if (bitmap_pos < 0)
-		die("Object not in bitmap: %s\n", oid_to_hex(&commit->object.oid));
+		die(_("object not in bitmap: '%s'"), oid_to_hex(&commit->object.oid));
 	test_bitmap_type(tdata, &commit->object, bitmap_pos);
 
 	bitmap_set(tdata->base, bitmap_pos);
@@ -1694,26 +1968,28 @@
 	struct ewah_bitmap *bm;
 
 	if (!(bitmap_git = prepare_bitmap_git(revs->repo)))
-		die("failed to load bitmap indexes");
+		die(_("failed to load bitmap indexes"));
 
 	if (revs->pending.nr != 1)
-		die("you must specify exactly one commit to test");
+		die(_("you must specify exactly one commit to test"));
 
-	fprintf(stderr, "Bitmap v%d test (%d entries loaded)\n",
-		bitmap_git->version, bitmap_git->entry_count);
+	fprintf_ln(stderr, "Bitmap v%d test (%d entries%s)",
+		bitmap_git->version,
+		bitmap_git->entry_count,
+		bitmap_git->table_lookup ? "" : " loaded");
 
 	root = revs->pending.objects[0].item;
 	bm = bitmap_for_commit(bitmap_git, (struct commit *)root);
 
 	if (bm) {
-		fprintf(stderr, "Found bitmap for %s. %d bits / %08x checksum\n",
+		fprintf_ln(stderr, "Found bitmap for '%s'. %d bits / %08x checksum",
 			oid_to_hex(&root->oid), (int)bm->bit_size, ewah_checksum(bm));
 
 		result = ewah_to_bitmap(bm);
 	}
 
 	if (!result)
-		die("Commit %s doesn't have an indexed bitmap", oid_to_hex(&root->oid));
+		die(_("commit '%s' doesn't have an indexed bitmap"), oid_to_hex(&root->oid));
 
 	revs->tag_objects = 1;
 	revs->tree_objects = 1;
@@ -1722,7 +1998,7 @@
 	result_popcnt = bitmap_popcount(result);
 
 	if (prepare_revision_walk(revs))
-		die("revision walk setup failed");
+		die(_("revision walk setup failed"));
 
 	tdata.bitmap_git = bitmap_git;
 	tdata.base = bitmap_new();
@@ -1738,9 +2014,9 @@
 	stop_progress(&tdata.prg);
 
 	if (bitmap_equals(result, tdata.base))
-		fprintf(stderr, "OK!\n");
+		fprintf_ln(stderr, "OK!");
 	else
-		die("mismatch in bitmap results");
+		die(_("mismatch in bitmap results"));
 
 	bitmap_free(result);
 	bitmap_free(tdata.base);
@@ -1753,15 +2029,24 @@
 
 int test_bitmap_commits(struct repository *r)
 {
-	struct bitmap_index *bitmap_git = prepare_bitmap_git(r);
 	struct object_id oid;
 	MAYBE_UNUSED void *value;
+	struct bitmap_index *bitmap_git = prepare_bitmap_git(r);
 
 	if (!bitmap_git)
-		die("failed to load bitmap indexes");
+		die(_("failed to load bitmap indexes"));
+
+	/*
+	 * As this function is only used to print bitmap selected
+	 * commits, we don't have to read the commit table.
+	 */
+	if (bitmap_git->table_lookup) {
+		if (load_bitmap_entries_v1(bitmap_git) < 0)
+			die(_("failed to load bitmap indexes"));
+	}
 
 	kh_foreach(bitmap_git->bitmaps, oid, value, {
-		printf("%s\n", oid_to_hex(&oid));
+		printf_ln("%s", oid_to_hex(&oid));
 	});
 
 	free_bitmap_index(bitmap_git);
@@ -1786,7 +2071,7 @@
 
 		nth_bitmap_object_oid(bitmap_git, &oid, index_pos);
 
-		printf("%s %"PRIu32"\n",
+		printf_ln("%s %"PRIu32"",
 		       oid_to_hex(&oid), get_be32(bitmap_git->hashes + index_pos));
 	}
 
@@ -1948,7 +2233,7 @@
 					struct object_id oid;
 					nth_midxed_object_oid(&oid, bitmap_git->midx, midx_pos);
 
-					die(_("could not find %s in pack %s at offset %"PRIuMAX),
+					die(_("could not find '%s' in pack '%s' at offset %"PRIuMAX),
 					    oid_to_hex(&oid),
 					    pack->pack_name,
 					    (uintmax_t)offset);
@@ -1984,7 +2269,7 @@
 			continue;
 
 		if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
-			die(_("unable to get disk usage of %s"),
+			die(_("unable to get disk usage of '%s'"),
 			    oid_to_hex(&obj->oid));
 
 		total += object_size;
diff --git a/pack-bitmap.h b/pack-bitmap.h
index 3d3ddd7..f0180b5 100644
--- a/pack-bitmap.h
+++ b/pack-bitmap.h
@@ -23,9 +23,19 @@
 
 #define NEEDS_BITMAP (1u<<22)
 
+/*
+ * The width in bytes of a single triplet in the lookup table
+ * extension:
+ *     (commit_pos, offset, xor_row)
+ *
+ * whose fields ar 32-, 64-, 32- bits wide, respectively.
+ */
+#define BITMAP_LOOKUP_TABLE_TRIPLET_WIDTH (16)
+
 enum pack_bitmap_opts {
-	BITMAP_OPT_FULL_DAG = 1,
-	BITMAP_OPT_HASH_CACHE = 4,
+	BITMAP_OPT_FULL_DAG = 0x1,
+	BITMAP_OPT_HASH_CACHE = 0x4,
+	BITMAP_OPT_LOOKUP_TABLE = 0x10,
 };
 
 enum pack_bitmap_flags {
@@ -75,7 +85,7 @@
 off_t get_disk_usage_from_bitmap(struct bitmap_index *, struct rev_info *);
 
 void bitmap_writer_show_progress(int show);
-void bitmap_writer_set_checksum(unsigned char *sha1);
+void bitmap_writer_set_checksum(const unsigned char *sha1);
 void bitmap_writer_build_type_index(struct packing_data *to_pack,
 				    struct pack_idx_entry **index,
 				    uint32_t index_nr);
diff --git a/pack-revindex.h b/pack-revindex.h
index 74f4eae..4974e75 100644
--- a/pack-revindex.h
+++ b/pack-revindex.h
@@ -22,7 +22,7 @@
  *
  *   - pack position refers to an object's position within a non-existent pack
  *     described by the MIDX. The pack structure is described in
- *     Documentation/technical/pack-format.txt.
+ *     gitformat-pack(5).
  *
  *     It is effectively a concatanation of all packs in the MIDX (ordered by
  *     their numeric ID within the MIDX) in their original order within each
diff --git a/packfile.c b/packfile.c
index e5b1d0e..c0d7dd9 100644
--- a/packfile.c
+++ b/packfile.c
@@ -941,20 +941,10 @@
 	return r->objects->approximate_object_count;
 }
 
-static void *get_next_packed_git(const void *p)
-{
-	return ((const struct packed_git *)p)->next;
-}
+DEFINE_LIST_SORT(static, sort_packs, struct packed_git, next);
 
-static void set_next_packed_git(void *p, void *next)
+static int sort_pack(const struct packed_git *a, const struct packed_git *b)
 {
-	((struct packed_git *)p)->next = next;
-}
-
-static int sort_pack(const void *a_, const void *b_)
-{
-	const struct packed_git *a = a_;
-	const struct packed_git *b = b_;
 	int st;
 
 	/*
@@ -981,9 +971,7 @@
 
 static void rearrange_packed_git(struct repository *r)
 {
-	r->objects->packed_git = llist_mergesort(
-		r->objects->packed_git, get_next_packed_git,
-		set_next_packed_git, sort_pack);
+	sort_packs(&r->objects->packed_git, sort_pack);
 }
 
 static void prepare_packed_git_mru(struct repository *r)
@@ -1404,7 +1392,7 @@
 	return a->p == b->p && a->base_offset == b->base_offset;
 }
 
-static int delta_base_cache_hash_cmp(const void *unused_cmp_data,
+static int delta_base_cache_hash_cmp(const void *cmp_data UNUSED,
 				     const struct hashmap_entry *va,
 				     const struct hashmap_entry *vb,
 				     const void *vkey)
@@ -2229,7 +2217,17 @@
 			       void *set_)
 {
 	struct oidset *set = set_;
-	struct object *obj = parse_object(the_repository, oid);
+	struct object *obj;
+	int we_parsed_object;
+
+	obj = lookup_object(the_repository, oid);
+	if (obj && obj->parsed) {
+		we_parsed_object = 0;
+	} else {
+		we_parsed_object = 1;
+		obj = parse_object(the_repository, oid);
+	}
+
 	if (!obj)
 		return 1;
 
@@ -2251,7 +2249,8 @@
 			return 0;
 		while (tree_entry_gently(&desc, &entry))
 			oidset_insert(set, &entry.oid);
-		free_tree_buffer(tree);
+		if (we_parsed_object)
+			free_tree_buffer(tree);
 	} else if (obj->type == OBJ_COMMIT) {
 		struct commit *commit = (struct commit *) obj;
 		struct commit_list *parents = commit->parents;
@@ -2275,7 +2274,8 @@
 		if (has_promisor_remote()) {
 			for_each_packed_object(add_promisor_object,
 					       &promisor_objects,
-					       FOR_EACH_OBJECT_PROMISOR_ONLY);
+					       FOR_EACH_OBJECT_PROMISOR_ONLY |
+					       FOR_EACH_OBJECT_PACK_ORDER);
 		}
 		promisor_objects_prepared = 1;
 	}
diff --git a/pager.c b/pager.c
index 5cfe23b..b66bbff 100644
--- a/pager.c
+++ b/pager.c
@@ -38,7 +38,8 @@
 	raise(signo);
 }
 
-static int core_pager_config(const char *var, const char *value, void *data)
+static int core_pager_config(const char *var, const char *value,
+			     void *data UNUSED)
 {
 	if (!strcmp(var, "core.pager"))
 		return git_config_string(&pager_program, var, value);
diff --git a/parse-options.c b/parse-options.c
index edf55d3..a1ec932 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -324,6 +324,8 @@
 		const char *rest, *long_name = options->long_name;
 		enum opt_parsed flags = OPT_LONG, opt_flags = OPT_LONG;
 
+		if (options->type == OPTION_SUBCOMMAND)
+			continue;
 		if (!long_name)
 			continue;
 
@@ -332,7 +334,7 @@
 			rest = NULL;
 		if (!rest) {
 			/* abbreviated? */
-			if (!(p->flags & PARSE_OPT_KEEP_UNKNOWN) &&
+			if (!(p->flags & PARSE_OPT_KEEP_UNKNOWN_OPT) &&
 			    !strncmp(long_name, arg, arg_end - arg)) {
 is_abbreviated:
 				if (abbrev_option &&
@@ -419,6 +421,19 @@
 	return PARSE_OPT_ERROR;
 }
 
+static enum parse_opt_result parse_subcommand(const char *arg,
+					      const struct option *options)
+{
+	for (; options->type != OPTION_END; options++)
+		if (options->type == OPTION_SUBCOMMAND &&
+		    !strcmp(options->long_name, arg)) {
+			*(parse_opt_subcommand_fn **)options->value = options->subcommand_fn;
+			return PARSE_OPT_SUBCOMMAND;
+		}
+
+	return PARSE_OPT_UNKNOWN;
+}
+
 static void check_typos(const char *arg, const struct option *options)
 {
 	if (strlen(arg) < 3)
@@ -442,6 +457,7 @@
 static void parse_options_check(const struct option *opts)
 {
 	char short_opts[128];
+	void *subcommand_value = NULL;
 
 	memset(short_opts, '\0', sizeof(short_opts));
 	for (; opts->type != OPTION_END; opts++) {
@@ -489,6 +505,14 @@
 			       "Are you using parse_options_step() directly?\n"
 			       "That case is not supported yet.");
 			break;
+		case OPTION_SUBCOMMAND:
+			if (!opts->value || !opts->subcommand_fn)
+				optbug(opts, "OPTION_SUBCOMMAND needs a value and a subcommand function");
+			if (!subcommand_value)
+				subcommand_value = opts->value;
+			else if (subcommand_value != opts->value)
+				optbug(opts, "all OPTION_SUBCOMMANDs need the same value");
+			break;
 		default:
 			; /* ok. (usually accepts an argument) */
 		}
@@ -499,6 +523,14 @@
 	BUG_if_bug("invalid 'struct option'");
 }
 
+static int has_subcommands(const struct option *options)
+{
+	for (; options->type != OPTION_END; options++)
+		if (options->type == OPTION_SUBCOMMAND)
+			return 1;
+	return 0;
+}
+
 static void parse_options_start_1(struct parse_opt_ctx_t *ctx,
 				  int argc, const char **argv, const char *prefix,
 				  const struct option *options,
@@ -515,7 +547,20 @@
 	ctx->prefix = prefix;
 	ctx->cpidx = ((flags & PARSE_OPT_KEEP_ARGV0) != 0);
 	ctx->flags = flags;
-	if ((flags & PARSE_OPT_KEEP_UNKNOWN) &&
+	ctx->has_subcommands = has_subcommands(options);
+	if (!ctx->has_subcommands && (flags & PARSE_OPT_SUBCOMMAND_OPTIONAL))
+		BUG("Using PARSE_OPT_SUBCOMMAND_OPTIONAL without subcommands");
+	if (ctx->has_subcommands) {
+		if (flags & PARSE_OPT_STOP_AT_NON_OPTION)
+			BUG("subcommands are incompatible with PARSE_OPT_STOP_AT_NON_OPTION");
+		if (!(flags & PARSE_OPT_SUBCOMMAND_OPTIONAL)) {
+			if (flags & PARSE_OPT_KEEP_UNKNOWN_OPT)
+				BUG("subcommands are incompatible with PARSE_OPT_KEEP_UNKNOWN_OPT unless in combination with PARSE_OPT_SUBCOMMAND_OPTIONAL");
+			if (flags & PARSE_OPT_KEEP_DASHDASH)
+				BUG("subcommands are incompatible with PARSE_OPT_KEEP_DASHDASH unless in combination with PARSE_OPT_SUBCOMMAND_OPTIONAL");
+		}
+	}
+	if ((flags & PARSE_OPT_KEEP_UNKNOWN_OPT) &&
 	    (flags & PARSE_OPT_STOP_AT_NON_OPTION) &&
 	    !(flags & PARSE_OPT_ONE_SHOT))
 		BUG("STOP_AT_NON_OPTION and KEEP_UNKNOWN don't go together");
@@ -589,6 +634,7 @@
 	int nr_noopts = 0;
 
 	for (; opts->type != OPTION_END; opts++) {
+		const char *prefix = "--";
 		const char *suffix = "";
 
 		if (!opts->long_name)
@@ -598,6 +644,9 @@
 			continue;
 
 		switch (opts->type) {
+		case OPTION_SUBCOMMAND:
+			prefix = "";
+			break;
 		case OPTION_GROUP:
 			continue;
 		case OPTION_STRING:
@@ -620,7 +669,8 @@
 			suffix = "=";
 		if (starts_with(opts->long_name, "no-"))
 			nr_noopts++;
-		printf(" --%s%s", opts->long_name, suffix);
+		printf("%s%s%s%s", opts == original_opts ? "" : " ",
+		       prefix, opts->long_name, suffix);
 	}
 	show_negated_gitcomp(original_opts, show_all, -1);
 	show_negated_gitcomp(original_opts, show_all, nr_noopts);
@@ -743,10 +793,38 @@
 		if (*arg != '-' || !arg[1]) {
 			if (parse_nodash_opt(ctx, arg, options) == 0)
 				continue;
-			if (ctx->flags & PARSE_OPT_STOP_AT_NON_OPTION)
-				return PARSE_OPT_NON_OPTION;
-			ctx->out[ctx->cpidx++] = ctx->argv[0];
-			continue;
+			if (!ctx->has_subcommands) {
+				if (ctx->flags & PARSE_OPT_STOP_AT_NON_OPTION)
+					return PARSE_OPT_NON_OPTION;
+				ctx->out[ctx->cpidx++] = ctx->argv[0];
+				continue;
+			}
+			switch (parse_subcommand(arg, options)) {
+			case PARSE_OPT_SUBCOMMAND:
+				return PARSE_OPT_SUBCOMMAND;
+			case PARSE_OPT_UNKNOWN:
+				if (ctx->flags & PARSE_OPT_SUBCOMMAND_OPTIONAL)
+					/*
+					 * arg is neither a short or long
+					 * option nor a subcommand.  Since
+					 * this command has a default
+					 * operation mode, we have to treat
+					 * this arg and all remaining args
+					 * as args meant to that default
+					 * operation mode.
+					 * So we are done parsing.
+					 */
+					return PARSE_OPT_DONE;
+				error(_("unknown subcommand: `%s'"), arg);
+				usage_with_options(usagestr, options);
+			case PARSE_OPT_COMPLETE:
+			case PARSE_OPT_HELP:
+			case PARSE_OPT_ERROR:
+			case PARSE_OPT_DONE:
+			case PARSE_OPT_NON_OPTION:
+				/* Impossible. */
+				BUG("parse_subcommand() cannot return these");
+			}
 		}
 
 		/* lone -h asks for help */
@@ -774,6 +852,7 @@
 					goto show_usage;
 				goto unknown;
 			case PARSE_OPT_NON_OPTION:
+			case PARSE_OPT_SUBCOMMAND:
 			case PARSE_OPT_HELP:
 			case PARSE_OPT_COMPLETE:
 				BUG("parse_short_opt() cannot return these");
@@ -799,6 +878,7 @@
 					*(char *)ctx->argv[0] = '-';
 					goto unknown;
 				case PARSE_OPT_NON_OPTION:
+				case PARSE_OPT_SUBCOMMAND:
 				case PARSE_OPT_COMPLETE:
 				case PARSE_OPT_HELP:
 					BUG("parse_short_opt() cannot return these");
@@ -830,6 +910,7 @@
 		case PARSE_OPT_HELP:
 			goto show_usage;
 		case PARSE_OPT_NON_OPTION:
+		case PARSE_OPT_SUBCOMMAND:
 		case PARSE_OPT_COMPLETE:
 			BUG("parse_long_opt() cannot return these");
 		case PARSE_OPT_DONE:
@@ -839,7 +920,19 @@
 unknown:
 		if (ctx->flags & PARSE_OPT_ONE_SHOT)
 			break;
-		if (!(ctx->flags & PARSE_OPT_KEEP_UNKNOWN))
+		if (ctx->has_subcommands &&
+		    (ctx->flags & PARSE_OPT_SUBCOMMAND_OPTIONAL) &&
+		    (ctx->flags & PARSE_OPT_KEEP_UNKNOWN_OPT)) {
+			/*
+			 * Found an unknown option given to a command with
+			 * subcommands that has a default operation mode:
+			 * we treat this option and all remaining args as
+			 * arguments meant to that default operation mode.
+			 * So we are done parsing.
+			 */
+			return PARSE_OPT_DONE;
+		}
+		if (!(ctx->flags & PARSE_OPT_KEEP_UNKNOWN_OPT))
 			return PARSE_OPT_UNKNOWN;
 		ctx->out[ctx->cpidx++] = ctx->argv[0];
 		ctx->opt = NULL;
@@ -884,7 +977,14 @@
 	case PARSE_OPT_COMPLETE:
 		exit(0);
 	case PARSE_OPT_NON_OPTION:
+	case PARSE_OPT_SUBCOMMAND:
+		break;
 	case PARSE_OPT_DONE:
+		if (ctx.has_subcommands &&
+		    !(flags & PARSE_OPT_SUBCOMMAND_OPTIONAL)) {
+			error(_("need a subcommand"));
+			usage_with_options(usagestr, options);
+		}
 		break;
 	case PARSE_OPT_UNKNOWN:
 		if (ctx.argv[0][1] == '-') {
@@ -1009,6 +1109,8 @@
 		size_t pos;
 		int pad;
 
+		if (opts->type == OPTION_SUBCOMMAND)
+			continue;
 		if (opts->type == OPTION_GROUP) {
 			fputc('\n', outfile);
 			need_newline = 0;
diff --git a/parse-options.h b/parse-options.h
index 685fcca..b6ef86e 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -11,6 +11,7 @@
 	OPTION_GROUP,
 	OPTION_NUMBER,
 	OPTION_ALIAS,
+	OPTION_SUBCOMMAND,
 	/* options with no arguments */
 	OPTION_BIT,
 	OPTION_NEGBIT,
@@ -30,10 +31,11 @@
 	PARSE_OPT_KEEP_DASHDASH = 1 << 0,
 	PARSE_OPT_STOP_AT_NON_OPTION = 1 << 1,
 	PARSE_OPT_KEEP_ARGV0 = 1 << 2,
-	PARSE_OPT_KEEP_UNKNOWN = 1 << 3,
+	PARSE_OPT_KEEP_UNKNOWN_OPT = 1 << 3,
 	PARSE_OPT_NO_INTERNAL_HELP = 1 << 4,
 	PARSE_OPT_ONE_SHOT = 1 << 5,
 	PARSE_OPT_SHELL_EVAL = 1 << 6,
+	PARSE_OPT_SUBCOMMAND_OPTIONAL = 1 << 7,
 };
 
 enum parse_opt_option_flags {
@@ -56,6 +58,7 @@
 	PARSE_OPT_ERROR = -1,	/* must be the same as error() */
 	PARSE_OPT_DONE = 0,	/* fixed so that "return 0" works */
 	PARSE_OPT_NON_OPTION,
+	PARSE_OPT_SUBCOMMAND,
 	PARSE_OPT_UNKNOWN
 };
 
@@ -67,6 +70,9 @@
 					      const struct option *opt,
 					      const char *arg, int unset);
 
+typedef int parse_opt_subcommand_fn(int argc, const char **argv,
+				    const char *prefix);
+
 /*
  * `type`::
  *   holds the type of the option, you must have an OPTION_END last in your
@@ -76,7 +82,8 @@
  *   the character to use as a short option name, '\0' if none.
  *
  * `long_name`::
- *   the long option name, without the leading dashes, NULL if none.
+ *   the long option (without the leading dashes) or subcommand name,
+ *   NULL if none.
  *
  * `value`::
  *   stores pointers to the values to be filled.
@@ -93,7 +100,7 @@
  *
  * `help`::
  *   the short help associated to what the option does.
- *   Must never be NULL (except for OPTION_END).
+ *   Must never be NULL (except for OPTION_END and OPTION_SUBCOMMAND).
  *   OPTION_GROUP uses this pointer to store the group header.
  *   Should be wrapped by N_() for translation.
  *
@@ -109,7 +116,8 @@
  *				is last on the command line. If the option is
  *				not last it will require an argument.
  *				Should not be used with PARSE_OPT_OPTARG.
- *   PARSE_OPT_NODASH: this option doesn't start with a dash.
+ *   PARSE_OPT_NODASH: this option doesn't start with a dash; can only be a
+ *		       short option and can't accept arguments.
  *   PARSE_OPT_LITERAL_ARGHELP: says that argh shouldn't be enclosed in brackets
  *				(i.e. '<argh>') in the help message.
  *				Useful for options with multiple parameters.
@@ -130,6 +138,9 @@
  * `ll_callback`::
  *   pointer to the callback to use for OPTION_LOWLEVEL_CALLBACK
  *
+ * `subcommand_fn`::
+ *   pointer to a function to use for OPTION_SUBCOMMAND.
+ *   It will be put in value when the subcommand is given on the command line.
  */
 struct option {
 	enum parse_opt_type type;
@@ -144,6 +155,7 @@
 	intptr_t defval;
 	parse_opt_ll_cb *ll_callback;
 	intptr_t extra;
+	parse_opt_subcommand_fn *subcommand_fn;
 };
 
 #define OPT_BIT_F(s, l, v, h, b, f) { OPTION_BIT, (s), (l), (v), NULL, (h), \
@@ -205,6 +217,14 @@
 #define OPT_ALIAS(s, l, source_long_name) \
 	{ OPTION_ALIAS, (s), (l), (source_long_name) }
 
+#define OPT_SUBCOMMAND_F(l, v, fn, f) { \
+	.type = OPTION_SUBCOMMAND, \
+	.long_name = (l), \
+	.value = (v), \
+	.flags = (f), \
+	.subcommand_fn = (fn) }
+#define OPT_SUBCOMMAND(l, v, fn)    OPT_SUBCOMMAND_F((l), (v), (fn), 0)
+
 /*
  * parse_options() will filter out the processed options and leave the
  * non-option arguments in argv[]. argv0 is assumed program name and
@@ -294,6 +314,7 @@
 	int argc, cpidx, total;
 	const char *opt;
 	enum parse_opt_flags flags;
+	unsigned has_subcommands;
 	const char *prefix;
 	const char **alias_groups; /* must be in groups of 3 elements! */
 	struct option *updated_options;
diff --git a/patch-ids.c b/patch-ids.c
index 8bf4255..46c6a8f 100644
--- a/patch-ids.c
+++ b/patch-ids.c
@@ -38,7 +38,7 @@
 static int patch_id_neq(const void *cmpfn_data,
 			const struct hashmap_entry *eptr,
 			const struct hashmap_entry *entry_or_key,
-			const void *unused_keydata)
+			const void *keydata UNUSED)
 {
 	/* NEEDSWORK: const correctness? */
 	struct diff_options *opt = (void *)cmpfn_data;
diff --git a/pathspec.c b/pathspec.c
index 84ad9c7..46e77a8 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -759,3 +759,92 @@
 
 	return 1;
 }
+
+int pathspec_needs_expanded_index(struct index_state *istate,
+				  const struct pathspec *pathspec)
+{
+	unsigned int i, pos;
+	int res = 0;
+	char *skip_worktree_seen = NULL;
+
+	/*
+	 * If index is not sparse, no index expansion is needed.
+	 */
+	if (!istate->sparse_index)
+		return 0;
+
+	/*
+	 * When using a magic pathspec, assume for the sake of simplicity that
+	 * the index needs to be expanded to match all matchable files.
+	 */
+	if (pathspec->magic)
+		return 1;
+
+	for (i = 0; i < pathspec->nr; i++) {
+		struct pathspec_item item = pathspec->items[i];
+
+		/*
+		 * If the pathspec item has a wildcard, the index should be expanded
+		 * if the pathspec has the possibility of matching a subset of entries inside
+		 * of a sparse directory (but not the entire directory).
+		 *
+		 * If the pathspec item is a literal path, the index only needs to be expanded
+		 * if a) the pathspec isn't in the sparse checkout cone (to make sure we don't
+		 * expand for in-cone files) and b) it doesn't match any sparse directories
+		 * (since we can reset whole sparse directories without expanding them).
+		 */
+		if (item.nowildcard_len < item.len) {
+			/*
+			 * Special case: if the pattern is a path inside the cone
+			 * followed by only wildcards, the pattern cannot match
+			 * partial sparse directories, so we know we don't need to
+			 * expand the index.
+			 *
+			 * Examples:
+			 * - in-cone/foo***: doesn't need expanded index
+			 * - not-in-cone/bar*: may need expanded index
+			 * - **.c: may need expanded index
+			 */
+			if (strspn(item.original + item.nowildcard_len, "*") == item.len - item.nowildcard_len &&
+			    path_in_cone_mode_sparse_checkout(item.original, istate))
+				continue;
+
+			for (pos = 0; pos < istate->cache_nr; pos++) {
+				struct cache_entry *ce = istate->cache[pos];
+
+				if (!S_ISSPARSEDIR(ce->ce_mode))
+					continue;
+
+				/*
+				 * If the pre-wildcard length is longer than the sparse
+				 * directory name and the sparse directory is the first
+				 * component of the pathspec, need to expand the index.
+				 */
+				if (item.nowildcard_len > ce_namelen(ce) &&
+				    !strncmp(item.original, ce->name, ce_namelen(ce))) {
+					res = 1;
+					break;
+				}
+
+				/*
+				 * If the pre-wildcard length is shorter than the sparse
+				 * directory and the pathspec does not match the whole
+				 * directory, need to expand the index.
+				 */
+				if (!strncmp(item.original, ce->name, item.nowildcard_len) &&
+				    wildmatch(item.original, ce->name, 0)) {
+					res = 1;
+					break;
+				}
+			}
+		} else if (!path_in_cone_mode_sparse_checkout(item.original, istate) &&
+			   !matches_skip_worktree(pathspec, i, &skip_worktree_seen))
+			res = 1;
+
+		if (res > 0)
+			break;
+	}
+
+	free(skip_worktree_seen);
+	return res;
+}
diff --git a/pathspec.h b/pathspec.h
index 402ebb8..41f6adf 100644
--- a/pathspec.h
+++ b/pathspec.h
@@ -171,4 +171,16 @@
 			 const char *name, int namelen,
 			 const struct pathspec_item *item);
 
+/*
+ * Determine whether a pathspec will match only entire index entries (non-sparse
+ * files and/or entire sparse directories). If the pathspec has the potential to
+ * match partial contents of a sparse directory, return 1 to indicate the index
+ * should be expanded to match the  appropriate index entries.
+ *
+ * For the sake of simplicity, always return 1 if using a more complex "magic"
+ * pathspec.
+ */
+int pathspec_needs_expanded_index(struct index_state *istate,
+				  const struct pathspec *pathspec);
+
 #endif /* PATHSPEC_H */
diff --git a/pkt-line.c b/pkt-line.c
index 8e43c2d..ce4e73b 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -309,7 +309,8 @@
 	return err;
 }
 
-int write_packetized_from_buf_no_flush(const char *src_in, size_t len, int fd_out)
+int write_packetized_from_buf_no_flush_count(const char *src_in, size_t len,
+					     int fd_out, int *packet_counter)
 {
 	int err = 0;
 	size_t bytes_written = 0;
@@ -324,6 +325,8 @@
 			break;
 		err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
 		bytes_written += bytes_to_write;
+		if (packet_counter)
+			(*packet_counter)++;
 	}
 	return err;
 }
diff --git a/pkt-line.h b/pkt-line.h
index 1f623de..79c538b 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -32,7 +32,13 @@
 int packet_flush_gently(int fd);
 int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
 int write_packetized_from_fd_no_flush(int fd_in, int fd_out);
-int write_packetized_from_buf_no_flush(const char *src_in, size_t len, int fd_out);
+int write_packetized_from_buf_no_flush_count(const char *src_in, size_t len,
+					     int fd_out, int *packet_counter);
+static inline int write_packetized_from_buf_no_flush(const char *src_in,
+						     size_t len, int fd_out)
+{
+	return write_packetized_from_buf_no_flush_count(src_in, len, fd_out, NULL);
+}
 
 /*
  * Stdio versions of packet_write functions. When mixing these with fd
diff --git a/ppc/sha1.c b/ppc/sha1.c
deleted file mode 100644
index 1b705ce..0000000
--- a/ppc/sha1.c
+++ /dev/null
@@ -1,72 +0,0 @@
-/*
- * SHA-1 implementation.
- *
- * Copyright (C) 2005 Paul Mackerras <paulus@samba.org>
- *
- * This version assumes we are running on a big-endian machine.
- * It calls an external sha1_core() to process blocks of 64 bytes.
- */
-#include <stdio.h>
-#include <string.h>
-#include "sha1.h"
-
-void ppc_sha1_core(uint32_t *hash, const unsigned char *p,
-		   unsigned int nblocks);
-
-int ppc_SHA1_Init(ppc_SHA_CTX *c)
-{
-	c->hash[0] = 0x67452301;
-	c->hash[1] = 0xEFCDAB89;
-	c->hash[2] = 0x98BADCFE;
-	c->hash[3] = 0x10325476;
-	c->hash[4] = 0xC3D2E1F0;
-	c->len = 0;
-	c->cnt = 0;
-	return 0;
-}
-
-int ppc_SHA1_Update(ppc_SHA_CTX *c, const void *ptr, unsigned long n)
-{
-	unsigned long nb;
-	const unsigned char *p = ptr;
-
-	c->len += (uint64_t) n << 3;
-	while (n != 0) {
-		if (c->cnt || n < 64) {
-			nb = 64 - c->cnt;
-			if (nb > n)
-				nb = n;
-			memcpy(&c->buf.b[c->cnt], p, nb);
-			if ((c->cnt += nb) == 64) {
-				ppc_sha1_core(c->hash, c->buf.b, 1);
-				c->cnt = 0;
-			}
-		} else {
-			nb = n >> 6;
-			ppc_sha1_core(c->hash, p, nb);
-			nb <<= 6;
-		}
-		n -= nb;
-		p += nb;
-	}
-	return 0;
-}
-
-int ppc_SHA1_Final(unsigned char *hash, ppc_SHA_CTX *c)
-{
-	unsigned int cnt = c->cnt;
-
-	c->buf.b[cnt++] = 0x80;
-	if (cnt > 56) {
-		if (cnt < 64)
-			memset(&c->buf.b[cnt], 0, 64 - cnt);
-		ppc_sha1_core(c->hash, c->buf.b, 1);
-		cnt = 0;
-	}
-	if (cnt < 56)
-		memset(&c->buf.b[cnt], 0, 56 - cnt);
-	c->buf.l[7] = c->len;
-	ppc_sha1_core(c->hash, c->buf.b, 1);
-	memcpy(hash, c->hash, 20);
-	return 0;
-}
diff --git a/ppc/sha1.h b/ppc/sha1.h
deleted file mode 100644
index 9b24b32..0000000
--- a/ppc/sha1.h
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * SHA-1 implementation.
- *
- * Copyright (C) 2005 Paul Mackerras <paulus@samba.org>
- */
-#include <stdint.h>
-
-typedef struct {
-	uint32_t hash[5];
-	uint32_t cnt;
-	uint64_t len;
-	union {
-		unsigned char b[64];
-		uint64_t l[8];
-	} buf;
-} ppc_SHA_CTX;
-
-int ppc_SHA1_Init(ppc_SHA_CTX *c);
-int ppc_SHA1_Update(ppc_SHA_CTX *c, const void *p, unsigned long n);
-int ppc_SHA1_Final(unsigned char *hash, ppc_SHA_CTX *c);
-
-#define platform_SHA_CTX	ppc_SHA_CTX
-#define platform_SHA1_Init	ppc_SHA1_Init
-#define platform_SHA1_Update	ppc_SHA1_Update
-#define platform_SHA1_Final	ppc_SHA1_Final
diff --git a/ppc/sha1ppc.S b/ppc/sha1ppc.S
deleted file mode 100644
index 1711eef..0000000
--- a/ppc/sha1ppc.S
+++ /dev/null
@@ -1,224 +0,0 @@
-/*
- * SHA-1 implementation for PowerPC.
- *
- * Copyright (C) 2005 Paul Mackerras <paulus@samba.org>
- */
-
-/*
- * PowerPC calling convention:
- * %r0 - volatile temp
- * %r1 - stack pointer.
- * %r2 - reserved
- * %r3-%r12 - Incoming arguments & return values; volatile.
- * %r13-%r31 - Callee-save registers
- * %lr - Return address, volatile
- * %ctr - volatile
- *
- * Register usage in this routine:
- * %r0 - temp
- * %r3 - argument (pointer to 5 words of SHA state)
- * %r4 - argument (pointer to data to hash)
- * %r5 - Constant K in SHA round (initially number of blocks to hash)
- * %r6-%r10 - Working copies of SHA variables A..E (actually E..A order)
- * %r11-%r26 - Data being hashed W[].
- * %r27-%r31 - Previous copies of A..E, for final add back.
- * %ctr - loop count
- */
-
-
-/*
- * We roll the registers for A, B, C, D, E around on each
- * iteration; E on iteration t is D on iteration t+1, and so on.
- * We use registers 6 - 10 for this.  (Registers 27 - 31 hold
- * the previous values.)
- */
-#define RA(t)	(((t)+4)%5+6)
-#define RB(t)	(((t)+3)%5+6)
-#define RC(t)	(((t)+2)%5+6)
-#define RD(t)	(((t)+1)%5+6)
-#define RE(t)	(((t)+0)%5+6)
-
-/* We use registers 11 - 26 for the W values */
-#define W(t)	((t)%16+11)
-
-/* Register 5 is used for the constant k */
-
-/*
- * The basic SHA-1 round function is:
- * E += ROTL(A,5) + F(B,C,D) + W[i] + K;  B = ROTL(B,30)
- * Then the variables are renamed: (A,B,C,D,E) = (E,A,B,C,D).
- *
- * Every 20 rounds, the function F() and the constant K changes:
- * - 20 rounds of f0(b,c,d) = "bit wise b ? c : d" =  (^b & d) + (b & c)
- * - 20 rounds of f1(b,c,d) = b^c^d = (b^d)^c
- * - 20 rounds of f2(b,c,d) = majority(b,c,d) = (b&d) + ((b^d)&c)
- * - 20 more rounds of f1(b,c,d)
- *
- * These are all scheduled for near-optimal performance on a G4.
- * The G4 is a 3-issue out-of-order machine with 3 ALUs, but it can only
- * *consider* starting the oldest 3 instructions per cycle.  So to get
- * maximum performance out of it, you have to treat it as an in-order
- * machine.  Which means interleaving the computation round t with the
- * computation of W[t+4].
- *
- * The first 16 rounds use W values loaded directly from memory, while the
- * remaining 64 use values computed from those first 16.  We preload
- * 4 values before starting, so there are three kinds of rounds:
- * - The first 12 (all f0) also load the W values from memory.
- * - The next 64 compute W(i+4) in parallel. 8*f0, 20*f1, 20*f2, 16*f1.
- * - The last 4 (all f1) do not do anything with W.
- *
- * Therefore, we have 6 different round functions:
- * STEPD0_LOAD(t,s) - Perform round t and load W(s).  s < 16
- * STEPD0_UPDATE(t,s) - Perform round t and compute W(s).  s >= 16.
- * STEPD1_UPDATE(t,s)
- * STEPD2_UPDATE(t,s)
- * STEPD1(t) - Perform round t with no load or update.
- *
- * The G5 is more fully out-of-order, and can find the parallelism
- * by itself.  The big limit is that it has a 2-cycle ALU latency, so
- * even though it's 2-way, the code has to be scheduled as if it's
- * 4-way, which can be a limit.  To help it, we try to schedule the
- * read of RA(t) as late as possible so it doesn't stall waiting for
- * the previous round's RE(t-1), and we try to rotate RB(t) as early
- * as possible while reading RC(t) (= RB(t-1)) as late as possible.
- */
-
-/* the initial loads. */
-#define LOADW(s) \
-	lwz	W(s),(s)*4(%r4)
-
-/*
- * Perform a step with F0, and load W(s).  Uses W(s) as a temporary
- * before loading it.
- * This is actually 10 instructions, which is an awkward fit.
- * It can execute grouped as listed, or delayed one instruction.
- * (If delayed two instructions, there is a stall before the start of the
- * second line.)  Thus, two iterations take 7 cycles, 3.5 cycles per round.
- */
-#define STEPD0_LOAD(t,s) \
-add RE(t),RE(t),W(t); andc   %r0,RD(t),RB(t);  and    W(s),RC(t),RB(t); \
-add RE(t),RE(t),%r0;  rotlwi %r0,RA(t),5;      rotlwi RB(t),RB(t),30;   \
-add RE(t),RE(t),W(s); add    %r0,%r0,%r5;      lwz    W(s),(s)*4(%r4);  \
-add RE(t),RE(t),%r0
-
-/*
- * This is likewise awkward, 13 instructions.  However, it can also
- * execute starting with 2 out of 3 possible moduli, so it does 2 rounds
- * in 9 cycles, 4.5 cycles/round.
- */
-#define STEPD0_UPDATE(t,s,loadk...) \
-add RE(t),RE(t),W(t); andc   %r0,RD(t),RB(t); xor    W(s),W((s)-16),W((s)-3); \
-add RE(t),RE(t),%r0;  and    %r0,RC(t),RB(t); xor    W(s),W(s),W((s)-8);      \
-add RE(t),RE(t),%r0;  rotlwi %r0,RA(t),5;     xor    W(s),W(s),W((s)-14);     \
-add RE(t),RE(t),%r5;  loadk; rotlwi RB(t),RB(t),30;  rotlwi W(s),W(s),1;     \
-add RE(t),RE(t),%r0
-
-/* Nicely optimal.  Conveniently, also the most common. */
-#define STEPD1_UPDATE(t,s,loadk...) \
-add RE(t),RE(t),W(t); xor    %r0,RD(t),RB(t); xor    W(s),W((s)-16),W((s)-3); \
-add RE(t),RE(t),%r5;  loadk; xor %r0,%r0,RC(t);  xor W(s),W(s),W((s)-8);      \
-add RE(t),RE(t),%r0;  rotlwi %r0,RA(t),5;     xor    W(s),W(s),W((s)-14);     \
-add RE(t),RE(t),%r0;  rotlwi RB(t),RB(t),30;  rotlwi W(s),W(s),1
-
-/*
- * The naked version, no UPDATE, for the last 4 rounds.  3 cycles per.
- * We could use W(s) as a temp register, but we don't need it.
- */
-#define STEPD1(t) \
-                        add   RE(t),RE(t),W(t); xor    %r0,RD(t),RB(t); \
-rotlwi RB(t),RB(t),30;  add   RE(t),RE(t),%r5;  xor    %r0,%r0,RC(t);   \
-add    RE(t),RE(t),%r0; rotlwi %r0,RA(t),5;     /* spare slot */        \
-add    RE(t),RE(t),%r0
-
-/*
- * 14 instructions, 5 cycles per.  The majority function is a bit
- * awkward to compute.  This can execute with a 1-instruction delay,
- * but it causes a 2-instruction delay, which triggers a stall.
- */
-#define STEPD2_UPDATE(t,s,loadk...) \
-add RE(t),RE(t),W(t); and    %r0,RD(t),RB(t); xor    W(s),W((s)-16),W((s)-3); \
-add RE(t),RE(t),%r0;  xor    %r0,RD(t),RB(t); xor    W(s),W(s),W((s)-8);      \
-add RE(t),RE(t),%r5;  loadk; and %r0,%r0,RC(t);  xor W(s),W(s),W((s)-14);     \
-add RE(t),RE(t),%r0;  rotlwi %r0,RA(t),5;     rotlwi W(s),W(s),1;             \
-add RE(t),RE(t),%r0;  rotlwi RB(t),RB(t),30
-
-#define STEP0_LOAD4(t,s)		\
-	STEPD0_LOAD(t,s);		\
-	STEPD0_LOAD((t+1),(s)+1);	\
-	STEPD0_LOAD((t)+2,(s)+2);	\
-	STEPD0_LOAD((t)+3,(s)+3)
-
-#define STEPUP4(fn, t, s, loadk...)		\
-	STEP##fn##_UPDATE(t,s,);		\
-	STEP##fn##_UPDATE((t)+1,(s)+1,);	\
-	STEP##fn##_UPDATE((t)+2,(s)+2,);	\
-	STEP##fn##_UPDATE((t)+3,(s)+3,loadk)
-
-#define STEPUP20(fn, t, s, loadk...)	\
-	STEPUP4(fn, t, s,);		\
-	STEPUP4(fn, (t)+4, (s)+4,);	\
-	STEPUP4(fn, (t)+8, (s)+8,);	\
-	STEPUP4(fn, (t)+12, (s)+12,);	\
-	STEPUP4(fn, (t)+16, (s)+16, loadk)
-
-	.globl	ppc_sha1_core
-ppc_sha1_core:
-	stwu	%r1,-80(%r1)
-	stmw	%r13,4(%r1)
-
-	/* Load up A - E */
-	lmw	%r27,0(%r3)
-
-	mtctr	%r5
-
-1:
-	LOADW(0)
-	lis	%r5,0x5a82
-	mr	RE(0),%r31
-	LOADW(1)
-	mr	RD(0),%r30
-	mr	RC(0),%r29
-	LOADW(2)
-	ori	%r5,%r5,0x7999	/* K0-19 */
-	mr	RB(0),%r28
-	LOADW(3)
-	mr	RA(0),%r27
-
-	STEP0_LOAD4(0, 4)
-	STEP0_LOAD4(4, 8)
-	STEP0_LOAD4(8, 12)
-	STEPUP4(D0, 12, 16,)
-	STEPUP4(D0, 16, 20, lis %r5,0x6ed9)
-
-	ori	%r5,%r5,0xeba1	/* K20-39 */
-	STEPUP20(D1, 20, 24, lis %r5,0x8f1b)
-
-	ori	%r5,%r5,0xbcdc	/* K40-59 */
-	STEPUP20(D2, 40, 44, lis %r5,0xca62)
-
-	ori	%r5,%r5,0xc1d6	/* K60-79 */
-	STEPUP4(D1, 60, 64,)
-	STEPUP4(D1, 64, 68,)
-	STEPUP4(D1, 68, 72,)
-	STEPUP4(D1, 72, 76,)
-	addi	%r4,%r4,64
-	STEPD1(76)
-	STEPD1(77)
-	STEPD1(78)
-	STEPD1(79)
-
-	/* Add results to original values */
-	add	%r31,%r31,RE(0)
-	add	%r30,%r30,RD(0)
-	add	%r29,%r29,RC(0)
-	add	%r28,%r28,RB(0)
-	add	%r27,%r27,RA(0)
-
-	bdnz	1b
-
-	/* Save final hash, restore registers, and return */
-	stmw	%r27,0(%r3)
-	lmw	%r13,4(%r1)
-	addi	%r1,%r1,80
-	blr
diff --git a/preload-index.c b/preload-index.c
index e5529a5..100f7a3 100644
--- a/preload-index.c
+++ b/preload-index.c
@@ -151,6 +151,12 @@
 	}
 	stop_progress(&pd.progress);
 
+	if (pathspec) {
+		/* earlier we made deep copies for each thread to work with */
+		for (i = 0; i < threads; i++)
+			clear_pathspec(&data[i].pathspec);
+	}
+
 	trace_performance_leave("preload index");
 
 	trace2_data_intmax("index", NULL, "preload/sum_lstat", t2_sum_lstat);
diff --git a/pretty.c b/pretty.c
index ee6114e..6cb363a 100644
--- a/pretty.c
+++ b/pretty.c
@@ -43,7 +43,8 @@
 	rev->commit_format = CMIT_FMT_USERFORMAT;
 }
 
-static int git_pretty_formats_config(const char *var, const char *value, void *cb)
+static int git_pretty_formats_config(const char *var, const char *value,
+				     void *cb UNUSED)
 {
 	struct cmt_fmt_map *commit_format = NULL;
 	const char *name;
@@ -477,6 +478,16 @@
 	}
 }
 
+static int use_in_body_from(const struct pretty_print_context *pp,
+			    const struct ident_split *ident)
+{
+	if (pp->rev && pp->rev->force_in_body_from)
+		return 1;
+	if (ident_cmp(pp->from_ident, ident))
+		return 1;
+	return 0;
+}
+
 void pp_user_info(struct pretty_print_context *pp,
 		  const char *what, struct strbuf *sb,
 		  const char *line, const char *encoding)
@@ -503,7 +514,7 @@
 		map_user(pp->mailmap, &mailbuf, &maillen, &namebuf, &namelen);
 
 	if (cmit_fmt_is_mail(pp->fmt)) {
-		if (pp->from_ident && ident_cmp(pp->from_ident, &ident)) {
+		if (pp->from_ident && use_in_body_from(pp, &ident)) {
 			struct strbuf buf = STRBUF_INIT;
 
 			strbuf_addstr(&buf, "From: ");
@@ -1575,23 +1586,7 @@
 				strbuf_addstr(sb, c->signature_check.primary_key_fingerprint);
 			break;
 		case 'T':
-			switch (c->signature_check.trust_level) {
-			case TRUST_UNDEFINED:
-				strbuf_addstr(sb, "undefined");
-				break;
-			case TRUST_NEVER:
-				strbuf_addstr(sb, "never");
-				break;
-			case TRUST_MARGINAL:
-				strbuf_addstr(sb, "marginal");
-				break;
-			case TRUST_FULLY:
-				strbuf_addstr(sb, "fully");
-				break;
-			case TRUST_ULTIMATE:
-				strbuf_addstr(sb, "ultimate");
-				break;
-			}
+			strbuf_addstr(sb, gpg_trust_level_to_str(c->signature_check.trust_level));
 			break;
 		default:
 			return 0;
diff --git a/promisor-remote.c b/promisor-remote.c
index 5b33f88..68f46f5 100644
--- a/promisor-remote.c
+++ b/promisor-remote.c
@@ -146,7 +146,7 @@
 	if (r->promisor_remote_config)
 		return;
 	config = r->promisor_remote_config =
-		xcalloc(sizeof(*r->promisor_remote_config), 1);
+		xcalloc(1, sizeof(*r->promisor_remote_config));
 	config->promisors_tail = &config->promisors;
 
 	repo_config(r, promisor_remote_config, config);
diff --git a/range-diff.c b/range-diff.c
index f63b3ff..8b7d81a 100644
--- a/range-diff.c
+++ b/range-diff.c
@@ -57,9 +57,9 @@
 		     "--pretty=medium",
 		     "--notes",
 		     NULL);
+	strvec_push(&cp.args, range);
 	if (other_arg)
 		strvec_pushv(&cp.args, other_arg->v);
-	strvec_push(&cp.args, range);
 	cp.out = -1;
 	cp.no_stdin = 1;
 	cp.git_cmd = 1;
@@ -224,8 +224,10 @@
 	return ret;
 }
 
-static int patch_util_cmp(const void *dummy, const struct patch_util *a,
-			  const struct patch_util *b, const char *keydata)
+static int patch_util_cmp(const void *cmp_data UNUSED,
+			  const struct patch_util *a,
+			  const struct patch_util *b,
+			  const char *keydata)
 {
 	return strcmp(a->diff, keydata ? keydata : b->diff);
 }
diff --git a/rebase-interactive.c b/rebase-interactive.c
index 87649d0..7407c59 100644
--- a/rebase-interactive.c
+++ b/rebase-interactive.c
@@ -54,9 +54,12 @@
 "l, label <label> = label current HEAD with a name\n"
 "t, reset <label> = reset HEAD to a label\n"
 "m, merge [-C <commit> | -c <commit>] <label> [# <oneline>]\n"
-".       create a merge commit using the original merge commit's\n"
-".       message (or the oneline, if no original merge commit was\n"
-".       specified); use -c <commit> to reword the commit message\n"
+"        create a merge commit using the original merge commit's\n"
+"        message (or the oneline, if no original merge commit was\n"
+"        specified); use -c <commit> to reword the commit message\n"
+"u, update-ref <ref> = track a placeholder for the <ref> to be updated\n"
+"                      to this position in the new commits. The <ref> is\n"
+"                      updated at the end of the rebase\n"
 "\n"
 "These lines can be re-ordered; they are executed from top to bottom.\n");
 	unsigned edit_todo = !(shortrevisions && shortonto);
@@ -143,6 +146,12 @@
 		return -4;
 	}
 
+	/*
+	 * See if branches need to be added or removed from the update-refs
+	 * file based on the new todo list.
+	 */
+	todo_list_filter_update_refs(r, new_todo);
+
 	return 0;
 }
 
diff --git a/ref-filter.c b/ref-filter.c
index d3c90e5..fd1cb14 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -89,7 +89,7 @@
 	struct worktree *wt; /* key is wt->head_ref */
 };
 
-static int ref_to_worktree_map_cmpfnc(const void *unused_lookupdata,
+static int ref_to_worktree_map_cmpfnc(const void *lookupdata UNUSED,
 				      const struct hashmap_entry *eptr,
 				      const struct hashmap_entry *kptr,
 				      const void *keydata_aka_refname)
@@ -2405,6 +2405,7 @@
 int filter_refs(struct ref_array *array, struct ref_filter *filter, unsigned int type)
 {
 	struct ref_filter_cbdata ref_cbdata;
+	int save_commit_buffer_orig;
 	int ret = 0;
 
 	ref_cbdata.array = array;
@@ -2412,6 +2413,9 @@
 
 	filter->kind = type & FILTER_REFS_KIND_MASK;
 
+	save_commit_buffer_orig = save_commit_buffer;
+	save_commit_buffer = 0;
+
 	init_contains_cache(&ref_cbdata.contains_cache);
 	init_contains_cache(&ref_cbdata.no_contains_cache);
 
@@ -2444,6 +2448,7 @@
 	reach_filter(array, filter->reachable_from, INCLUDE_REACHED);
 	reach_filter(array, filter->unreachable_from, EXCLUDE_REACHED);
 
+	save_commit_buffer = save_commit_buffer_orig;
 	return ret;
 }
 
diff --git a/reflog.c b/reflog.c
index 135a1a6..d258fd3 100644
--- a/reflog.c
+++ b/reflog.c
@@ -240,8 +240,9 @@
  * Return true iff the specified reflog entry should be expired.
  */
 int should_expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
-			     const char *email, timestamp_t timestamp, int tz,
-			     const char *message, void *cb_data)
+			     const char *email UNUSED,
+			     timestamp_t timestamp, int tz UNUSED,
+			     const char *message UNUSED, void *cb_data)
 {
 	struct expire_reflog_policy_cb *cb = cb_data;
 	struct commit *old_commit, *new_commit;
@@ -294,7 +295,8 @@
 	return expire;
 }
 
-static int push_tip_to_list(const char *refname, const struct object_id *oid,
+static int push_tip_to_list(const char *refname UNUSED,
+			    const struct object_id *oid,
 			    int flags, void *cb_data)
 {
 	struct commit_list **list = cb_data;
@@ -378,9 +380,11 @@
 	}
 }
 
-int count_reflog_ent(struct object_id *ooid, struct object_id *noid,
-		     const char *email, timestamp_t timestamp, int tz,
-		     const char *message, void *cb_data)
+int count_reflog_ent(struct object_id *ooid UNUSED,
+		     struct object_id *noid UNUSED,
+		     const char *email UNUSED,
+		     timestamp_t timestamp, int tz UNUSED,
+		     const char *message UNUSED, void *cb_data)
 {
 	struct cmd_reflog_expire_cb *cb = cb_data;
 	if (!cb->expire_total || timestamp < cb->expire_total)
diff --git a/refs.c b/refs.c
index 90bcb27..c89d558 100644
--- a/refs.c
+++ b/refs.c
@@ -20,6 +20,7 @@
 #include "repository.h"
 #include "sigchain.h"
 #include "date.h"
+#include "commit.h"
 
 /*
  * List of all available backends
@@ -56,6 +57,88 @@
 	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 4, 4
 };
 
+struct ref_namespace_info ref_namespace[] = {
+	[NAMESPACE_HEAD] = {
+		.ref = "HEAD",
+		.decoration = DECORATION_REF_HEAD,
+		.exact = 1,
+	},
+	[NAMESPACE_BRANCHES] = {
+		.ref = "refs/heads/",
+		.decoration = DECORATION_REF_LOCAL,
+	},
+	[NAMESPACE_TAGS] = {
+		.ref = "refs/tags/",
+		.decoration = DECORATION_REF_TAG,
+	},
+	[NAMESPACE_REMOTE_REFS] = {
+		/*
+		 * The default refspec for new remotes copies refs from
+		 * refs/heads/ on the remote into refs/remotes/<remote>/.
+		 * As such, "refs/remotes/" has special handling.
+		 */
+		.ref = "refs/remotes/",
+		.decoration = DECORATION_REF_REMOTE,
+	},
+	[NAMESPACE_STASH] = {
+		/*
+		 * The single ref "refs/stash" stores the latest stash.
+		 * Older stashes can be found in the reflog.
+		 */
+		.ref = "refs/stash",
+		.exact = 1,
+		.decoration = DECORATION_REF_STASH,
+	},
+	[NAMESPACE_REPLACE] = {
+		/*
+		 * This namespace allows Git to act as if one object ID
+		 * points to the content of another. Unlike the other
+		 * ref namespaces, this one can be changed by the
+		 * GIT_REPLACE_REF_BASE environment variable. This
+		 * .namespace value will be overwritten in setup_git_env().
+		 */
+		.ref = "refs/replace/",
+		.decoration = DECORATION_GRAFTED,
+	},
+	[NAMESPACE_NOTES] = {
+		/*
+		 * The refs/notes/commit ref points to the tip of a
+		 * parallel commit history that adds metadata to commits
+		 * in the normal history. This ref can be overwritten
+		 * by the core.notesRef config variable or the
+		 * GIT_NOTES_REFS environment variable.
+		 */
+		.ref = "refs/notes/commit",
+		.exact = 1,
+	},
+	[NAMESPACE_PREFETCH] = {
+		/*
+		 * Prefetch refs are written by the background 'fetch'
+		 * maintenance task. It allows faster foreground fetches
+		 * by advertising these previously-downloaded tips without
+		 * updating refs/remotes/ without user intervention.
+		 */
+		.ref = "refs/prefetch/",
+	},
+	[NAMESPACE_REWRITTEN] = {
+		/*
+		 * Rewritten refs are used by the 'label' command in the
+		 * sequencer. These are particularly useful during an
+		 * interactive rebase that uses the 'merge' command.
+		 */
+		.ref = "refs/rewritten/",
+	},
+};
+
+void update_ref_namespace(enum ref_namespace namespace, char *ref)
+{
+	struct ref_namespace_info *info = &ref_namespace[namespace];
+	if (info->ref_updated)
+		free(info->ref);
+	info->ref = ref;
+	info->ref_updated = 1;
+}
+
 /*
  * Try to read one refname component from the front of refname.
  * Return the length of the component found, or -1 if the component is
@@ -358,7 +441,8 @@
 	const char *msg_fmt;
 };
 
-static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
+static int warn_if_dangling_symref(const char *refname,
+				   const struct object_id *oid UNUSED,
 				   int flags, void *cb_data)
 {
 	struct warn_if_dangling_data *d = cb_data;
@@ -455,11 +539,16 @@
 	if (*pattern == '/')
 		BUG("pattern must not start with '/'");
 
-	if (prefix) {
+	if (prefix)
 		strbuf_addstr(&normalized_pattern, prefix);
-	}
-	else if (!starts_with(pattern, "refs/"))
+	else if (!starts_with(pattern, "refs/") &&
+		   strcmp(pattern, "HEAD"))
 		strbuf_addstr(&normalized_pattern, "refs/");
+	/*
+	 * NEEDSWORK: Special case other symrefs such as REBASE_HEAD,
+	 * MERGE_HEAD, etc.
+	 */
+
 	strbuf_addstr(&normalized_pattern, pattern);
 	strbuf_strip_suffix(&normalized_pattern, "/");
 
@@ -893,8 +982,9 @@
 }
 
 static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
-		const char *email, timestamp_t timestamp, int tz,
-		const char *message, void *cb_data)
+			   const char *email UNUSED,
+			   timestamp_t timestamp, int tz,
+			   const char *message, void *cb_data)
 {
 	struct read_ref_at_cb *cb = cb_data;
 	int reached_count;
@@ -934,9 +1024,11 @@
 	return cb->found_it;
 }
 
-static int read_ref_at_ent_newest(struct object_id *ooid, struct object_id *noid,
-				  const char *email, timestamp_t timestamp,
-				  int tz, const char *message, void *cb_data)
+static int read_ref_at_ent_newest(struct object_id *ooid UNUSED,
+				  struct object_id *noid,
+				  const char *email UNUSED,
+				  timestamp_t timestamp, int tz,
+				  const char *message, void *cb_data)
 {
 	struct read_ref_at_cb *cb = cb_data;
 
@@ -947,8 +1039,9 @@
 }
 
 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
-				  const char *email, timestamp_t timestamp,
-				  int tz, const char *message, void *cb_data)
+				  const char *email UNUSED,
+				  timestamp_t timestamp, int tz,
+				  const char *message, void *cb_data)
 {
 	struct read_ref_at_cb *cb = cb_data;
 
@@ -1524,6 +1617,7 @@
 
 int for_each_replace_ref(struct repository *r, each_repo_ref_fn fn, void *cb_data)
 {
+	const char *git_replace_ref_base = ref_namespace[NAMESPACE_REPLACE].ref;
 	return do_for_each_repo_ref(r, git_replace_ref_base, fn,
 				    strlen(git_replace_ref_base),
 				    DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
@@ -1810,7 +1904,7 @@
 	char name[FLEX_ARRAY];
 };
 
-static int ref_store_hash_cmp(const void *unused_cmp_data,
+static int ref_store_hash_cmp(const void *cmp_data UNUSED,
 			      const struct hashmap_entry *eptr,
 			      const struct hashmap_entry *entry_or_key,
 			      const void *keydata)
diff --git a/refs.h b/refs.h
index 47cb9ed..d6575b8 100644
--- a/refs.h
+++ b/refs.h
@@ -2,6 +2,7 @@
 #define REFS_H
 
 #include "cache.h"
+#include "commit.h"
 
 struct object_id;
 struct ref_store;
@@ -930,4 +931,49 @@
 struct ref_store *get_submodule_ref_store(const char *submodule);
 struct ref_store *get_worktree_ref_store(const struct worktree *wt);
 
+/*
+ * Some of the names specified by refs have special meaning to Git.
+ * Organize these namespaces in a comon 'ref_namespace' array for
+ * reference from multiple places in the codebase.
+ */
+
+struct ref_namespace_info {
+	char *ref;
+	enum decoration_type decoration;
+
+	/*
+	 * If 'exact' is true, then we must match the 'ref' exactly.
+	 * Otherwise, use a prefix match.
+	 *
+	 * 'ref_updated' is for internal use. It represents whether the
+	 * 'ref' value was replaced from its original literal version.
+	 */
+	unsigned exact:1,
+		 ref_updated:1;
+};
+
+enum ref_namespace {
+	NAMESPACE_HEAD,
+	NAMESPACE_BRANCHES,
+	NAMESPACE_TAGS,
+	NAMESPACE_REMOTE_REFS,
+	NAMESPACE_STASH,
+	NAMESPACE_REPLACE,
+	NAMESPACE_NOTES,
+	NAMESPACE_PREFETCH,
+	NAMESPACE_REWRITTEN,
+
+	/* Must be last */
+	NAMESPACE__COUNT
+};
+
+/* See refs.c for the contents of this array. */
+extern struct ref_namespace_info ref_namespace[NAMESPACE__COUNT];
+
+/*
+ * Some ref namespaces can be modified by config values or environment
+ * variables. Modify a namespace as specified by its ref_namespace key.
+ */
+void update_ref_namespace(enum ref_namespace namespace, char *ref);
+
 #endif /* REFS_H */
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 8db7882..e4009b3 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2202,8 +2202,8 @@
 	return ok;
 }
 
-static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
-				      struct object_id *peeled)
+static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator UNUSED,
+				      struct object_id *peeled UNUSED)
 {
 	BUG("ref_iterator_peel() called for reflog_iterator");
 }
@@ -2257,7 +2257,7 @@
 static enum iterator_selection reflog_iterator_select(
 	struct ref_iterator *iter_worktree,
 	struct ref_iterator *iter_common,
-	void *cb_data)
+	void *cb_data UNUSED)
 {
 	if (iter_worktree) {
 		/*
@@ -2985,7 +2985,7 @@
 
 static int files_transaction_abort(struct ref_store *ref_store,
 				   struct ref_transaction *transaction,
-				   struct strbuf *err)
+				   struct strbuf *err UNUSED)
 {
 	struct files_ref_store *refs =
 		files_downcast(ref_store, 0, "ref_transaction_abort");
@@ -2995,7 +2995,9 @@
 }
 
 static int ref_present(const char *refname,
-		       const struct object_id *oid, int flags, void *cb_data)
+		       const struct object_id *oid UNUSED,
+		       int flags UNUSED,
+		       void *cb_data)
 {
 	struct string_list *affected_refnames = cb_data;
 
@@ -3259,7 +3261,7 @@
 	return -1;
 }
 
-static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
+static int files_init_db(struct ref_store *ref_store, struct strbuf *err UNUSED)
 {
 	struct files_ref_store *refs =
 		files_downcast(ref_store, REF_STORE_WRITE, "init_db");
diff --git a/refs/iterator.c b/refs/iterator.c
index b2e56ba..c9fd0bc 100644
--- a/refs/iterator.c
+++ b/refs/iterator.c
@@ -51,8 +51,8 @@
 	return ref_iterator_abort(ref_iterator);
 }
 
-static int empty_ref_iterator_peel(struct ref_iterator *ref_iterator,
-				   struct object_id *peeled)
+static int empty_ref_iterator_peel(struct ref_iterator *ref_iterator UNUSED,
+				   struct object_id *peeled UNUSED)
 {
 	BUG("peel called for empty iterator");
 }
@@ -238,7 +238,7 @@
  */
 static enum iterator_selection overlay_iterator_select(
 		struct ref_iterator *front, struct ref_iterator *back,
-		void *cb_data)
+		void *cb_data UNUSED)
 {
 	int cmp;
 
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 97b6837..43cdb97 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -726,7 +726,7 @@
 }
 
 static int packed_read_raw_ref(struct ref_store *ref_store, const char *refname,
-			       struct object_id *oid, struct strbuf *referent,
+			       struct object_id *oid, struct strbuf *referent UNUSED,
 			       unsigned int *type, int *failure_errno)
 {
 	struct packed_ref_store *refs =
@@ -1078,7 +1078,8 @@
 static const char PACKED_REFS_HEADER[] =
 	"# pack-refs with: peeled fully-peeled sorted \n";
 
-static int packed_init_db(struct ref_store *ref_store, struct strbuf *err)
+static int packed_init_db(struct ref_store *ref_store UNUSED,
+			  struct strbuf *err UNUSED)
 {
 	/* Nothing to do. */
 	return 0;
@@ -1473,7 +1474,7 @@
 
 static int packed_transaction_abort(struct ref_store *ref_store,
 				    struct ref_transaction *transaction,
-				    struct strbuf *err)
+				    struct strbuf *err UNUSED)
 {
 	struct packed_ref_store *refs = packed_downcast(
 			ref_store,
@@ -1512,7 +1513,7 @@
 	return ret;
 }
 
-static int packed_initial_transaction_commit(struct ref_store *ref_store,
+static int packed_initial_transaction_commit(struct ref_store *ref_store UNUSED,
 					    struct ref_transaction *transaction,
 					    struct strbuf *err)
 {
@@ -1568,7 +1569,8 @@
 	return ret;
 }
 
-static int packed_pack_refs(struct ref_store *ref_store, unsigned int flags)
+static int packed_pack_refs(struct ref_store *ref_store UNUSED,
+			    unsigned int flags UNUSED)
 {
 	/*
 	 * Packed refs are already packed. It might be that loose refs
@@ -1578,7 +1580,7 @@
 	return 0;
 }
 
-static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_store)
+static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_store UNUSED)
 {
 	return empty_ref_iterator_begin();
 }
diff --git a/refspec.h b/refspec.h
index 8b79891..8c0c446 100644
--- a/refspec.h
+++ b/refspec.h
@@ -69,7 +69,7 @@
 struct strvec;
 /*
  * Determine what <prefix> values to pass to the peer in ref-prefix lines
- * (see Documentation/technical/protocol-v2.txt).
+ * (see linkgit:gitprotocol-v2[5]).
  */
 void refspec_ref_prefixes(const struct refspec *rs,
 			  struct strvec *ref_prefixes);
diff --git a/reftable/reader.c b/reftable/reader.c
index 54b4025..b4db23c 100644
--- a/reftable/reader.c
+++ b/reftable/reader.c
@@ -443,7 +443,7 @@
 	return reader_table_iter_at(r, ti, off, typ);
 }
 
-static int reader_seek_linear(struct reftable_reader *r, struct table_iter *ti,
+static int reader_seek_linear(struct table_iter *ti,
 			      struct reftable_record *want)
 {
 	struct reftable_record rec =
@@ -510,7 +510,7 @@
 	if (err < 0)
 		goto done;
 
-	err = reader_seek_linear(r, &index_iter, &want_index);
+	err = reader_seek_linear(&index_iter, &want_index);
 	while (1) {
 		err = table_iter_next(&index_iter, &index_result);
 		table_iter_block_done(&index_iter);
@@ -570,7 +570,7 @@
 	err = reader_start(r, &ti, reftable_record_type(rec), 0);
 	if (err < 0)
 		return err;
-	err = reader_seek_linear(r, &ti, rec);
+	err = reader_seek_linear(&ti, rec);
 	if (err < 0)
 		return err;
 	else {
diff --git a/remote-curl.c b/remote-curl.c
index 67f178b..72dfb8f 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -580,6 +580,7 @@
 	char *service_url;
 	char *hdr_content_type;
 	char *hdr_accept;
+	char *hdr_accept_language;
 	char *protocol_header;
 	char *buf;
 	size_t alloc;
@@ -607,6 +608,8 @@
 	unsigned flush_read_but_not_sent : 1;
 };
 
+#define RPC_STATE_INIT { 0 }
+
 /*
  * Appends the result of reading from rpc->out to the string represented by
  * rpc->buf and rpc->len if there is enough space. Returns 1 if there was
@@ -932,6 +935,10 @@
 	headers = curl_slist_append(headers, needs_100_continue ?
 		"Expect: 100-continue" : "Expect:");
 
+	/* Add Accept-Language header */
+	if (rpc->hdr_accept_language)
+		headers = curl_slist_append(headers, rpc->hdr_accept_language);
+
 	/* Add the extra Git-Protocol header */
 	if (rpc->protocol_header)
 		headers = curl_slist_append(headers, rpc->protocol_header);
@@ -1080,6 +1087,8 @@
 	strbuf_addf(&buf, "%s%s", url.buf, svc);
 	rpc->service_url = strbuf_detach(&buf, NULL);
 
+	rpc->hdr_accept_language = xstrdup_or_null(http_get_accept_language_header());
+
 	strbuf_addf(&buf, "Content-Type: application/x-%s-request", svc);
 	rpc->hdr_content_type = strbuf_detach(&buf, NULL);
 
@@ -1118,6 +1127,7 @@
 	free(rpc->service_url);
 	free(rpc->hdr_content_type);
 	free(rpc->hdr_accept);
+	free(rpc->hdr_accept_language);
 	free(rpc->protocol_header);
 	free(rpc->buf);
 	strbuf_release(&buf);
@@ -1153,7 +1163,7 @@
 static int fetch_git(struct discovery *heads,
 	int nr_heads, struct ref **to_fetch)
 {
-	struct rpc_state rpc;
+	struct rpc_state rpc = RPC_STATE_INIT;
 	struct strbuf preamble = STRBUF_INIT;
 	int i, err;
 	struct strvec args = STRVEC_INIT;
@@ -1276,6 +1286,29 @@
 	strbuf_reset(buf);
 }
 
+static void parse_get(const char *arg)
+{
+	struct strbuf url = STRBUF_INIT;
+	struct strbuf path = STRBUF_INIT;
+	const char *space;
+
+	space = strchr(arg, ' ');
+
+	if (!space)
+		die(_("protocol error: expected '<url> <path>', missing space"));
+
+	strbuf_add(&url, arg, space - arg);
+	strbuf_addstr(&path, space + 1);
+
+	if (http_get_file(url.buf, path.buf, NULL))
+		die(_("failed to download file at URL '%s'"), url.buf);
+
+	strbuf_release(&url);
+	strbuf_release(&path);
+	printf("\n");
+	fflush(stdout);
+}
+
 static int push_dav(int nr_spec, const char **specs)
 {
 	struct child_process child = CHILD_PROCESS_INIT;
@@ -1299,7 +1332,7 @@
 
 static int push_git(struct discovery *heads, int nr_spec, const char **specs)
 {
-	struct rpc_state rpc;
+	struct rpc_state rpc = RPC_STATE_INIT;
 	int i, err;
 	struct strvec args;
 	struct string_list_item *cas_option;
@@ -1398,8 +1431,9 @@
 static int stateless_connect(const char *service_name)
 {
 	struct discovery *discover;
-	struct rpc_state rpc;
+	struct rpc_state rpc = RPC_STATE_INIT;
 	struct strbuf buf = STRBUF_INIT;
+	const char *accept_language;
 
 	/*
 	 * Run the info/refs request and see if the server supports protocol
@@ -1418,6 +1452,9 @@
 		printf("\n");
 		fflush(stdout);
 	}
+	accept_language = http_get_accept_language_header();
+	if (accept_language)
+		rpc.hdr_accept_language = xstrfmt("%s", accept_language);
 
 	rpc.service_name = service_name;
 	rpc.service_url = xstrfmt("%s%s", url.buf, rpc.service_name);
@@ -1467,6 +1504,7 @@
 	free(rpc.service_url);
 	free(rpc.hdr_content_type);
 	free(rpc.hdr_accept);
+	free(rpc.hdr_accept_language);
 	free(rpc.protocol_header);
 	free(rpc.buf);
 	strbuf_release(&buf);
@@ -1549,9 +1587,14 @@
 				printf("unsupported\n");
 			fflush(stdout);
 
+		} else if (skip_prefix(buf.buf, "get ", &arg)) {
+			parse_get(arg);
+			fflush(stdout);
+
 		} else if (!strcmp(buf.buf, "capabilities")) {
 			printf("stateless-connect\n");
 			printf("fetch\n");
+			printf("get\n");
 			printf("option\n");
 			printf("push\n");
 			printf("check-connectivity\n");
diff --git a/remote.c b/remote.c
index b19e3a2..60869be 100644
--- a/remote.c
+++ b/remote.c
@@ -11,7 +11,6 @@
 #include "dir.h"
 #include "tag.h"
 #include "string-list.h"
-#include "mergesort.h"
 #include "strvec.h"
 #include "commit-reach.h"
 #include "advice.h"
@@ -87,7 +86,7 @@
 	int len;
 };
 
-static int remotes_hash_cmp(const void *unused_cmp_data,
+static int remotes_hash_cmp(const void *cmp_data UNUSED,
 			    const struct hashmap_entry *eptr,
 			    const struct hashmap_entry *entry_or_key,
 			    const void *keydata)
@@ -171,7 +170,7 @@
 	int len;
 };
 
-static int branches_hash_cmp(const void *unused_cmp_data,
+static int branches_hash_cmp(const void *cmp_data UNUSED,
 			     const struct hashmap_entry *eptr,
 			     const struct hashmap_entry *entry_or_key,
 			     const void *keydata)
@@ -850,7 +849,7 @@
 	return !strcmp(refspec->src, name);
 }
 
-static int omit_name_by_refspec(const char *name, struct refspec *rs)
+int omit_name_by_refspec(const char *name, struct refspec *rs)
 {
 	int i;
 
@@ -1082,27 +1081,6 @@
 	}
 }
 
-int ref_compare_name(const void *va, const void *vb)
-{
-	const struct ref *a = va, *b = vb;
-	return strcmp(a->name, b->name);
-}
-
-static void *ref_list_get_next(const void *a)
-{
-	return ((const struct ref *)a)->next;
-}
-
-static void ref_list_set_next(void *a, void *next)
-{
-	((struct ref *)a)->next = next;
-}
-
-void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
-{
-	*l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
-}
-
 int count_refspec_match(const char *pattern,
 			struct ref *refs,
 			struct ref **matched_ref)
@@ -2169,6 +2147,9 @@
 	struct object_id oid;
 	struct commit *ours, *theirs;
 	struct rev_info revs;
+	struct setup_revision_opt opt = {
+		.free_removed_argv_elements = 1,
+	};
 	struct strvec argv = STRVEC_INIT;
 
 	/* Cannot stat if what we used to build on no longer exists */
@@ -2203,7 +2184,7 @@
 	strvec_push(&argv, "--");
 
 	repo_init_revisions(the_repository, &revs, NULL);
-	setup_revisions(argv.nr, argv.v, &revs, NULL);
+	setup_revisions(argv.nr, argv.v, &revs, &opt);
 	if (prepare_revision_walk(&revs))
 		die(_("revision walk setup failed"));
 
@@ -2339,7 +2320,8 @@
 }
 
 static int one_local_ref(const char *refname, const struct object_id *oid,
-			 int flag, void *cb_data)
+			 int flag UNUSED,
+			 void *cb_data)
 {
 	struct ref ***local_tail = cb_data;
 	struct ref *ref;
@@ -2595,19 +2577,22 @@
 };
 
 /* Get the timestamp of the latest entry. */
-static int peek_reflog(struct object_id *o_oid, struct object_id *n_oid,
-		       const char *ident, timestamp_t timestamp,
-		       int tz, const char *message, void *cb_data)
+static int peek_reflog(struct object_id *o_oid UNUSED,
+		       struct object_id *n_oid UNUSED,
+		       const char *ident UNUSED,
+		       timestamp_t timestamp, int tz UNUSED,
+		       const char *message UNUSED, void *cb_data)
 {
 	timestamp_t *ts = cb_data;
 	*ts = timestamp;
 	return 1;
 }
 
-static int check_and_collect_until(struct object_id *o_oid,
+static int check_and_collect_until(struct object_id *o_oid UNUSED,
 				   struct object_id *n_oid,
-				   const char *ident, timestamp_t timestamp,
-				   int tz, const char *message, void *cb_data)
+				   const char *ident UNUSED,
+				   timestamp_t timestamp, int tz UNUSED,
+				   const char *message UNUSED, void *cb_data)
 {
 	struct commit *commit;
 	struct check_and_collect_until_cb_data *cb = cb_data;
diff --git a/remote.h b/remote.h
index dd44024..1c4621b 100644
--- a/remote.h
+++ b/remote.h
@@ -207,9 +207,7 @@
 struct ref *alloc_ref(const char *name);
 struct ref *copy_ref(const struct ref *ref);
 struct ref *copy_ref_list(const struct ref *ref);
-void sort_ref_list(struct ref **, int (*cmp)(const void *, const void *));
 int count_refspec_match(const char *, struct ref *refs, struct ref **matched_ref);
-int ref_compare_name(const void *, const void *);
 
 int check_ref_type(const struct ref *ref, int flags);
 
@@ -248,6 +246,12 @@
 struct ref *ref_remove_duplicates(struct ref *ref_map);
 
 /*
+ * Check whether a name matches any negative refspec in rs. Returns 1 if the
+ * name matches at least one negative refspec, and 0 otherwise.
+ */
+int omit_name_by_refspec(const char *name, struct refspec *rs);
+
+/*
  * Remove all entries in the input list which match any negative refspec in
  * the refspec list.
  */
diff --git a/replace-object.c b/replace-object.c
index 7bd9aba..320be25 100644
--- a/replace-object.c
+++ b/replace-object.c
@@ -9,7 +9,8 @@
 static int register_replace_ref(struct repository *r,
 				const char *refname,
 				const struct object_id *oid,
-				int flag, void *cb_data)
+				int flag UNUSED,
+				void *cb_data UNUSED)
 {
 	/* Get sha1 from refname */
 	const char *slash = strrchr(refname, '/');
diff --git a/repo-settings.c b/repo-settings.c
index 2dfcb2b..e8b5815 100644
--- a/repo-settings.c
+++ b/repo-settings.c
@@ -11,11 +11,18 @@
 		*dest = def;
 }
 
+static void repo_cfg_int(struct repository *r, const char *key, int *dest,
+			 int def)
+{
+	if (repo_config_get_int(r, key, dest))
+		*dest = def;
+}
+
 void prepare_repo_settings(struct repository *r)
 {
 	int experimental;
 	int value;
-	char *strval;
+	const char *strval;
 	int manyfiles;
 
 	if (!r->gitdir)
@@ -42,11 +49,14 @@
 		r->settings.core_untracked_cache = UNTRACKED_CACHE_WRITE;
 	}
 
-	/* Boolean config or default, does not cascade (simple)  */
+	/* Commit graph config or default, does not cascade (simple) */
 	repo_cfg_bool(r, "core.commitgraph", &r->settings.core_commit_graph, 1);
+	repo_cfg_int(r, "commitgraph.generationversion", &r->settings.commit_graph_generation_version, 2);
 	repo_cfg_bool(r, "commitgraph.readchangedpaths", &r->settings.commit_graph_read_changed_paths, 1);
 	repo_cfg_bool(r, "gc.writecommitgraph", &r->settings.gc_write_commit_graph, 1);
 	repo_cfg_bool(r, "fetch.writecommitgraph", &r->settings.fetch_write_commit_graph, 0);
+
+	/* Boolean config or default, does not cascade (simple)  */
 	repo_cfg_bool(r, "pack.usesparse", &r->settings.pack_use_sparse, 1);
 	repo_cfg_bool(r, "core.multipackindex", &r->settings.core_multi_pack_index, 1);
 	repo_cfg_bool(r, "index.sparse", &r->settings.sparse_index, 0);
@@ -67,7 +77,7 @@
 	if (!repo_config_get_int(r, "index.version", &value))
 		r->settings.index_version = value;
 
-	if (!repo_config_get_string(r, "core.untrackedcache", &strval)) {
+	if (!repo_config_get_string_tmp(r, "core.untrackedcache", &strval)) {
 		int v = git_parse_maybe_bool(strval);
 
 		/*
@@ -78,10 +88,9 @@
 		if (v >= 0)
 			r->settings.core_untracked_cache = v ?
 				UNTRACKED_CACHE_WRITE : UNTRACKED_CACHE_REMOVE;
-		free(strval);
 	}
 
-	if (!repo_config_get_string(r, "fetch.negotiationalgorithm", &strval)) {
+	if (!repo_config_get_string_tmp(r, "fetch.negotiationalgorithm", &strval)) {
 		int fetch_default = r->settings.fetch_negotiation_algorithm;
 		if (!strcasecmp(strval, "skipping"))
 			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_SKIPPING;
diff --git a/repository.h b/repository.h
index 6cc661e..24316ac 100644
--- a/repository.h
+++ b/repository.h
@@ -1,6 +1,7 @@
 #ifndef REPOSITORY_H
 #define REPOSITORY_H
 
+#include "git-compat-util.h"
 #include "path.h"
 
 struct config_set;
@@ -30,6 +31,7 @@
 	int initialized;
 
 	int core_commit_graph;
+	int commit_graph_generation_version;
 	int commit_graph_read_changed_paths;
 	int gc_write_commit_graph;
 	int fetch_write_commit_graph;
@@ -185,6 +187,7 @@
 void repo_set_worktree(struct repository *repo, const char *path);
 void repo_set_hash_algo(struct repository *repo, int algo);
 void initialize_the_repository(void);
+RESULT_MUST_BE_USED
 int repo_init(struct repository *r, const char *gitdir, const char *worktree);
 
 /*
@@ -196,6 +199,7 @@
  * Return 0 upon success and a non-zero value upon failure.
  */
 struct object_id;
+RESULT_MUST_BE_USED
 int repo_submodule_init(struct repository *subrepo,
 			struct repository *superproject,
 			const char *path,
diff --git a/revision.c b/revision.c
index 0c6e26c..d5f4463 100644
--- a/revision.c
+++ b/revision.c
@@ -119,10 +119,10 @@
 	struct oidset trees;
 };
 
-static int path_and_oids_cmp(const void *hashmap_cmp_fn_data,
+static int path_and_oids_cmp(const void *hashmap_cmp_fn_data UNUSED,
 			     const struct hashmap_entry *eptr,
 			     const struct hashmap_entry *entry_or_key,
-			     const void *keydata)
+			     const void *keydata UNUSED)
 {
 	const struct path_and_oids_entry *e1, *e2;
 
@@ -373,18 +373,10 @@
 				    unsigned int flags)
 {
 	struct object *object;
-	struct commit *commit;
 
-	/*
-	 * If the repository has commit graphs, we try to opportunistically
-	 * look up the object ID in those graphs. Like this, we can avoid
-	 * parsing commit data from disk.
-	 */
-	commit = lookup_commit_in_graph(revs->repo, oid);
-	if (commit)
-		object = &commit->object;
-	else
-		object = parse_object(revs->repo, oid);
+	object = parse_object_with_flags(revs->repo, oid,
+					 revs->verify_objects ? 0 :
+					 PARSE_OBJECT_SKIP_HASH_CHECK);
 
 	if (!object) {
 		if (revs->ignore_missing)
@@ -1105,7 +1097,7 @@
 			   struct commit_list **list, struct prio_queue *queue)
 {
 	struct commit_list *parent = commit->parents;
-	unsigned left_flag;
+	unsigned pass_flags;
 
 	if (commit->object.flags & ADDED)
 		return 0;
@@ -1160,7 +1152,7 @@
 	if (revs->no_walk)
 		return 0;
 
-	left_flag = (commit->object.flags & SYMMETRIC_LEFT);
+	pass_flags = (commit->object.flags & (SYMMETRIC_LEFT | ANCESTRY_PATH));
 
 	for (parent = commit->parents; parent; parent = parent->next) {
 		struct commit *p = parent->item;
@@ -1181,7 +1173,7 @@
 			if (!*slot)
 				*slot = *revision_sources_at(revs->sources, commit);
 		}
-		p->object.flags |= left_flag;
+		p->object.flags |= pass_flags;
 		if (!(p->object.flags & SEEN)) {
 			p->object.flags |= (SEEN | NOT_USER_GIVEN);
 			if (list)
@@ -1304,13 +1296,24 @@
 }
 
 /*
- * "rev-list --ancestry-path A..B" computes commits that are ancestors
- * of B but not ancestors of A but further limits the result to those
- * that are descendants of A.  This takes the list of bottom commits and
- * the result of "A..B" without --ancestry-path, and limits the latter
- * further to the ones that can reach one of the commits in "bottom".
+ * "rev-list --ancestry-path=C_0 [--ancestry-path=C_1 ...] A..B"
+ * computes commits that are ancestors of B but not ancestors of A but
+ * further limits the result to those that have any of C in their
+ * ancestry path (i.e. are either ancestors of any of C, descendants
+ * of any of C, or are any of C). If --ancestry-path is specified with
+ * no commit, we use all bottom commits for C.
+ *
+ * Before this function is called, ancestors of C will have already
+ * been marked with ANCESTRY_PATH previously.
+ *
+ * This takes the list of bottom commits and the result of "A..B"
+ * without --ancestry-path, and limits the latter further to the ones
+ * that have any of C in their ancestry path. Since the ancestors of C
+ * have already been marked (a prerequisite of this function), we just
+ * need to mark the descendants, then exclude any commit that does not
+ * have any of these marks.
  */
-static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
+static void limit_to_ancestry(struct commit_list *bottoms, struct commit_list *list)
 {
 	struct commit_list *p;
 	struct commit_list *rlist = NULL;
@@ -1323,7 +1326,7 @@
 	for (p = list; p; p = p->next)
 		commit_list_insert(p->item, &rlist);
 
-	for (p = bottom; p; p = p->next)
+	for (p = bottoms; p; p = p->next)
 		p->item->object.flags |= TMP_MARK;
 
 	/*
@@ -1356,38 +1359,39 @@
 	 */
 
 	/*
-	 * The ones that are not marked with TMP_MARK are uninteresting
+	 * The ones that are not marked with either TMP_MARK or
+	 * ANCESTRY_PATH are uninteresting
 	 */
 	for (p = list; p; p = p->next) {
 		struct commit *c = p->item;
-		if (c->object.flags & TMP_MARK)
+		if (c->object.flags & (TMP_MARK | ANCESTRY_PATH))
 			continue;
 		c->object.flags |= UNINTERESTING;
 	}
 
-	/* We are done with the TMP_MARK */
+	/* We are done with TMP_MARK and ANCESTRY_PATH */
 	for (p = list; p; p = p->next)
-		p->item->object.flags &= ~TMP_MARK;
-	for (p = bottom; p; p = p->next)
-		p->item->object.flags &= ~TMP_MARK;
+		p->item->object.flags &= ~(TMP_MARK | ANCESTRY_PATH);
+	for (p = bottoms; p; p = p->next)
+		p->item->object.flags &= ~(TMP_MARK | ANCESTRY_PATH);
 	free_commit_list(rlist);
 }
 
 /*
- * Before walking the history, keep the set of "negative" refs the
- * caller has asked to exclude.
+ * Before walking the history, add the set of "negative" refs the
+ * caller has asked to exclude to the bottom list.
  *
  * This is used to compute "rev-list --ancestry-path A..B", as we need
  * to filter the result of "A..B" further to the ones that can actually
  * reach A.
  */
-static struct commit_list *collect_bottom_commits(struct commit_list *list)
+static void collect_bottom_commits(struct commit_list *list,
+				   struct commit_list **bottom)
 {
-	struct commit_list *elem, *bottom = NULL;
+	struct commit_list *elem;
 	for (elem = list; elem; elem = elem->next)
 		if (elem->item->object.flags & BOTTOM)
-			commit_list_insert(elem->item, &bottom);
-	return bottom;
+			commit_list_insert(elem->item, bottom);
 }
 
 /* Assumes either left_only or right_only is set */
@@ -1414,12 +1418,12 @@
 	struct commit_list *original_list = revs->commits;
 	struct commit_list *newlist = NULL;
 	struct commit_list **p = &newlist;
-	struct commit_list *bottom = NULL;
 	struct commit *interesting_cache = NULL;
 
-	if (revs->ancestry_path) {
-		bottom = collect_bottom_commits(original_list);
-		if (!bottom)
+	if (revs->ancestry_path_implicit_bottoms) {
+		collect_bottom_commits(original_list,
+				       &revs->ancestry_path_bottoms);
+		if (!revs->ancestry_path_bottoms)
 			die("--ancestry-path given but there are no bottom commits");
 	}
 
@@ -1464,9 +1468,8 @@
 	if (revs->left_only || revs->right_only)
 		limit_left_right(newlist, revs);
 
-	if (bottom)
-		limit_to_ancestry(bottom, newlist);
-	free_commit_list(bottom);
+	if (revs->ancestry_path)
+		limit_to_ancestry(revs->ancestry_path_bottoms, newlist);
 
 	/*
 	 * Check if any commits have become TREESAME by some of their parents
@@ -1543,7 +1546,8 @@
 }
 
 static int handle_one_ref(const char *path, const struct object_id *oid,
-			  int flag, void *cb_data)
+			  int flag UNUSED,
+			  void *cb_data)
 {
 	struct all_refs_cb *cb = cb_data;
 	struct object *object;
@@ -1618,8 +1622,11 @@
 }
 
 static int handle_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
-		const char *email, timestamp_t timestamp, int tz,
-		const char *message, void *cb_data)
+				 const char *email UNUSED,
+				 timestamp_t timestamp UNUSED,
+				 int tz UNUSED,
+				 const char *message UNUSED,
+				 void *cb_data)
 {
 	handle_one_reflog_commit(ooid, cb_data);
 	handle_one_reflog_commit(noid, cb_data);
@@ -1627,8 +1634,8 @@
 }
 
 static int handle_one_reflog(const char *refname_in_wt,
-			     const struct object_id *oid,
-			     int flag, void *cb_data)
+			     const struct object_id *oid UNUSED,
+			     int flag UNUSED, void *cb_data)
 {
 	struct all_refs_cb *cb = cb_data;
 	struct strbuf refname = STRBUF_INIT;
@@ -2213,7 +2220,7 @@
 			       const struct setup_revision_opt* opt)
 {
 	const char *arg = argv[0];
-	const char *optarg;
+	const char *optarg = NULL;
 	int argcount;
 	const unsigned hexsz = the_hash_algo->hexsz;
 
@@ -2284,6 +2291,23 @@
 		revs->ancestry_path = 1;
 		revs->simplify_history = 0;
 		revs->limited = 1;
+		revs->ancestry_path_implicit_bottoms = 1;
+	} else if (skip_prefix(arg, "--ancestry-path=", &optarg)) {
+		struct commit *c;
+		struct object_id oid;
+		const char *msg = _("could not get commit for ancestry-path argument %s");
+
+		revs->ancestry_path = 1;
+		revs->simplify_history = 0;
+		revs->limited = 1;
+
+		if (repo_get_oid_committish(revs->repo, optarg, &oid))
+			return error(msg, optarg);
+		get_reference(revs, optarg, &oid, ANCESTRY_PATH);
+		c = lookup_commit_reference(revs->repo, &oid);
+		if (!c)
+			return error(msg, optarg);
+		commit_list_insert(c, &revs->ancestry_path_bottoms);
 	} else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
 		init_reflog_walk(&revs->reflog_info);
 	} else if (!strcmp(arg, "--default")) {
@@ -2398,6 +2422,7 @@
 		revs->tree_objects = 1;
 		revs->blob_objects = 1;
 		revs->verify_objects = 1;
+		disable_commit_graph(revs->repo);
 	} else if (!strcmp(arg, "--unpacked")) {
 		revs->unpacked = 1;
 	} else if (starts_with(arg, "--unpacked=")) {
@@ -2784,6 +2809,8 @@
 			const char *arg = argv[i];
 			if (strcmp(arg, "--"))
 				continue;
+			if (opt && opt->free_removed_argv_elements)
+				free((char *)argv[i]);
 			argv[i] = NULL;
 			argc = i;
 			if (argv[i + 1])
@@ -2991,6 +3018,7 @@
 void release_revisions(struct rev_info *revs)
 {
 	free_commit_list(revs->commits);
+	free_commit_list(revs->ancestry_path_bottoms);
 	object_array_clear(&revs->pending);
 	object_array_clear(&revs->boundary_commits);
 	release_revisions_cmdline(&revs->cmdline);
@@ -3791,51 +3819,6 @@
 	return 0;
 }
 
-static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
-{
-	char *person, *endp;
-	size_t len, namelen, maillen;
-	const char *name;
-	const char *mail;
-	struct ident_split ident;
-
-	person = strstr(buf->buf, what);
-	if (!person)
-		return 0;
-
-	person += strlen(what);
-	endp = strchr(person, '\n');
-	if (!endp)
-		return 0;
-
-	len = endp - person;
-
-	if (split_ident_line(&ident, person, len))
-		return 0;
-
-	mail = ident.mail_begin;
-	maillen = ident.mail_end - ident.mail_begin;
-	name = ident.name_begin;
-	namelen = ident.name_end - ident.name_begin;
-
-	if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
-		struct strbuf namemail = STRBUF_INIT;
-
-		strbuf_addf(&namemail, "%.*s <%.*s>",
-			    (int)namelen, name, (int)maillen, mail);
-
-		strbuf_splice(buf, ident.name_begin - buf->buf,
-			      ident.mail_end - ident.name_begin + 1,
-			      namemail.buf, namemail.len);
-
-		strbuf_release(&namemail);
-
-		return 1;
-	}
-
-	return 0;
-}
-
 static int commit_match(struct commit *commit, struct rev_info *opt)
 {
 	int retval;
@@ -3868,11 +3851,12 @@
 		strbuf_addstr(&buf, message);
 
 	if (opt->grep_filter.header_list && opt->mailmap) {
+		const char *commit_headers[] = { "author ", "committer ", NULL };
+
 		if (!buf.len)
 			strbuf_addstr(&buf, message);
 
-		commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
-		commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
+		apply_mailmap_to_header(&buf, commit_headers, opt->mailmap);
 	}
 
 	/* Append "fake" message parts as needed */
diff --git a/revision.h b/revision.h
index e576845..afe1b77 100644
--- a/revision.h
+++ b/revision.h
@@ -48,6 +48,7 @@
  */
 #define NOT_USER_GIVEN	(1u<<25)
 #define TRACK_LINEAR	(1u<<26)
+#define ANCESTRY_PATH	(1u<<27)
 #define ALL_REV_FLAGS	(((1u<<11)-1) | NOT_USER_GIVEN | TRACK_LINEAR | PULL_MERGE)
 
 #define DECORATE_SHORT_REFS	1
@@ -164,6 +165,13 @@
 			cherry_mark:1,
 			bisect:1,
 			ancestry_path:1,
+
+			/* True if --ancestry-path was specified without an
+			 * argument. The bottom revisions are implicitly
+			 * the arguments in this case.
+			 */
+			ancestry_path_implicit_bottoms:1,
+
 			first_parent_only:1,
 			exclude_first_parent_only:1,
 			line_level_traverse:1,
@@ -221,6 +229,7 @@
 			missing_newline:1,
 			date_mode_explicit:1,
 			preserve_subject:1,
+			force_in_body_from:1,
 			encode_email_headers:1,
 			include_header:1;
 	unsigned int	disable_stdin:1;
@@ -306,6 +315,7 @@
 	struct saved_parents *saved_parents_slab;
 
 	struct commit_list *previous_parents;
+	struct commit_list *ancestry_path_bottoms;
 	const char *break_bar;
 
 	struct revision_sources *sources;
@@ -375,7 +385,8 @@
 	const char *def;
 	void (*tweak)(struct rev_info *, struct setup_revision_opt *);
 	unsigned int	assume_dashdash:1,
-			allow_exclude_promisor_objects:1;
+			allow_exclude_promisor_objects:1,
+			free_removed_argv_elements:1;
 	unsigned revarg_opt;
 };
 int setup_revisions(int argc, const char **argv, struct rev_info *revs,
diff --git a/run-command.c b/run-command.c
index 14f1783..5ec3a46 100644
--- a/run-command.c
+++ b/run-command.c
@@ -10,6 +10,7 @@
 #include "config.h"
 #include "packfile.h"
 #include "hook.h"
+#include "compat/nonblock.h"
 
 void child_process_init(struct child_process *child)
 {
@@ -1364,12 +1365,25 @@
 			continue;
 
 		if (io->type == POLLOUT) {
-			ssize_t len = xwrite(io->fd,
-					     io->u.out.buf, io->u.out.len);
+			ssize_t len;
+
+			/*
+			 * Don't use xwrite() here. It loops forever on EAGAIN,
+			 * and we're in our own poll() loop here.
+			 *
+			 * Note that we lose xwrite()'s handling of MAX_IO_SIZE
+			 * and EINTR, so we have to implement those ourselves.
+			 */
+			len = write(io->fd, io->u.out.buf,
+				    io->u.out.len <= MAX_IO_SIZE ?
+				    io->u.out.len : MAX_IO_SIZE);
 			if (len < 0) {
-				io->error = errno;
-				close(io->fd);
-				io->fd = -1;
+				if (errno != EINTR && errno != EAGAIN &&
+				    errno != ENOSPC) {
+					io->error = errno;
+					close(io->fd);
+					io->fd = -1;
+				}
 			} else {
 				io->u.out.buf += len;
 				io->u.out.len -= len;
@@ -1438,6 +1452,15 @@
 		return -1;
 
 	if (in) {
+		if (enable_pipe_nonblock(cmd->in) < 0) {
+			error_errno("unable to make pipe non-blocking");
+			close(cmd->in);
+			if (out)
+				close(cmd->out);
+			if (err)
+				close(cmd->err);
+			return -1;
+		}
 		io[nr].fd = cmd->in;
 		io[nr].type = POLLOUT;
 		io[nr].u.out.buf = in;
diff --git a/send-pack.c b/send-pack.c
index bc0fcdb..f2e1983 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -84,6 +84,8 @@
 		strvec_push(&po.args, "--progress");
 	if (is_repository_shallow(the_repository))
 		strvec_push(&po.args, "--shallow");
+	if (args->disable_bitmaps)
+		strvec_push(&po.args, "--no-use-bitmap-index");
 	po.in = -1;
 	po.out = args->stateless_rpc ? -1 : fd;
 	po.git_cmd = 1;
@@ -264,7 +266,7 @@
 	return ret;
 }
 
-static int sideband_demux(int in, int out, void *data)
+static int sideband_demux(int in UNUSED, int out, void *data)
 {
 	int *fd = data, ret;
 	if (async_with_fork())
@@ -487,6 +489,7 @@
 	struct async demux;
 	const char *push_cert_nonce = NULL;
 	struct packet_reader reader;
+	int use_bitmaps;
 
 	if (!remote_refs) {
 		fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
@@ -498,6 +501,9 @@
 	if (push_negotiate)
 		get_commons_through_negotiation(args->url, remote_refs, &commons);
 
+	if (!git_config_get_bool("push.usebitmaps", &use_bitmaps))
+		args->disable_bitmaps = !use_bitmaps;
+
 	git_config_get_bool("transfer.advertisesid", &advertise_sid);
 
 	/* Does the other end support the reporting? */
diff --git a/send-pack.h b/send-pack.h
index e148fcd..7edb805 100644
--- a/send-pack.h
+++ b/send-pack.h
@@ -26,7 +26,8 @@
 		/* One of the SEND_PACK_PUSH_CERT_* constants. */
 		push_cert:2,
 		stateless_rpc:1,
-		atomic:1;
+		atomic:1,
+		disable_bitmaps:1;
 	const struct string_list *push_options;
 };
 
diff --git a/sequencer.c b/sequencer.c
index 61a8e00..d26ede8 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -35,6 +35,8 @@
 #include "commit-reach.h"
 #include "rebase-interactive.h"
 #include "reset.h"
+#include "branch.h"
+#include "log-tree.h"
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
@@ -148,6 +150,20 @@
 static GIT_PATH_FUNC(rebase_path_refs_to_delete, "rebase-merge/refs-to-delete")
 
 /*
+ * The update-refs file stores a list of refs that will be updated at the end
+ * of the rebase sequence. The 'update-ref <ref>' commands in the todo file
+ * update the OIDs for the refs in this file, but the refs are not updated
+ * until the end of the rebase sequence.
+ *
+ * rebase_path_update_refs() returns the path to this file for a given
+ * worktree directory. For the current worktree, pass the_repository->gitdir.
+ */
+static char *rebase_path_update_refs(const char *wt_git_dir)
+{
+	return xstrfmt("%s/rebase-merge/update-refs", wt_git_dir);
+}
+
+/*
  * The following files are written by git-rebase just after parsing the
  * command-line.
  */
@@ -169,6 +185,30 @@
 static GIT_PATH_FUNC(rebase_path_drop_redundant_commits, "rebase-merge/drop_redundant_commits")
 static GIT_PATH_FUNC(rebase_path_keep_redundant_commits, "rebase-merge/keep_redundant_commits")
 
+/**
+ * A 'struct update_refs_record' represents a value in the update-refs
+ * list. We use a string_list to map refs to these (before, after) pairs.
+ */
+struct update_ref_record {
+	struct object_id before;
+	struct object_id after;
+};
+
+static struct update_ref_record *init_update_ref_record(const char *ref)
+{
+	struct update_ref_record *rec;
+
+	CALLOC_ARRAY(rec, 1);
+
+	oidcpy(&rec->before, null_oid());
+	oidcpy(&rec->after, null_oid());
+
+	/* This may fail, but that's fine, we will keep the null OID. */
+	read_ref(ref, &rec->before);
+
+	return rec;
+}
+
 static int git_sequencer_config(const char *k, const char *v, void *cb)
 {
 	struct replay_opts *opts = cb;
@@ -497,7 +537,7 @@
 static int error_dirty_index(struct repository *repo, struct replay_opts *opts)
 {
 	if (repo_read_index_unmerged(repo))
-		return error_resolve_conflict(_(action_name(opts)));
+		return error_resolve_conflict(action_name(opts));
 
 	error(_("your local changes would be overwritten by %s."),
 		_(action_name(opts)));
@@ -535,7 +575,7 @@
 	if (checkout_fast_forward(r, from, to, 1))
 		return -1; /* the callee should have complained already */
 
-	strbuf_addf(&sb, _("%s: fast-forward"), _(action_name(opts)));
+	strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
@@ -1689,20 +1729,21 @@
 	char c;
 	const char *str;
 } todo_command_info[] = {
-	{ 'p', "pick" },
-	{ 0,   "revert" },
-	{ 'e', "edit" },
-	{ 'r', "reword" },
-	{ 'f', "fixup" },
-	{ 's', "squash" },
-	{ 'x', "exec" },
-	{ 'b', "break" },
-	{ 'l', "label" },
-	{ 't', "reset" },
-	{ 'm', "merge" },
-	{ 0,   "noop" },
-	{ 'd', "drop" },
-	{ 0,   NULL }
+	[TODO_PICK] = { 'p', "pick" },
+	[TODO_REVERT] = { 0,   "revert" },
+	[TODO_EDIT] = { 'e', "edit" },
+	[TODO_REWORD] = { 'r', "reword" },
+	[TODO_FIXUP] = { 'f', "fixup" },
+	[TODO_SQUASH] = { 's', "squash" },
+	[TODO_EXEC] = { 'x', "exec" },
+	[TODO_BREAK] = { 'b', "break" },
+	[TODO_LABEL] = { 'l', "label" },
+	[TODO_RESET] = { 't', "reset" },
+	[TODO_MERGE] = { 'm', "merge" },
+	[TODO_UPDATE_REF] = { 'u', "update-ref" },
+	[TODO_NOOP] = { 0,   "noop" },
+	[TODO_DROP] = { 'd', "drop" },
+	[TODO_COMMENT] = { 0,   NULL },
 };
 
 static const char *command_to_string(const enum todo_command command)
@@ -2381,7 +2422,7 @@
 	if (repo_read_index(r) < 0) {
 		rollback_lock_file(&index_lock);
 		return error(_("git %s: failed to read the index"),
-			_(action_name(opts)));
+			action_name(opts));
 	}
 	refresh_index(r->index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 
@@ -2389,7 +2430,7 @@
 		if (write_locked_index(r->index, &index_lock,
 				       COMMIT_LOCK | SKIP_IF_UNCHANGED)) {
 			return error(_("git %s: failed to refresh the index"),
-				_(action_name(opts)));
+				action_name(opts));
 		}
 	}
 
@@ -2481,7 +2522,7 @@
 			     command_to_string(item->command));
 
 	if (item->command == TODO_EXEC || item->command == TODO_LABEL ||
-	    item->command == TODO_RESET) {
+	    item->command == TODO_RESET || item->command == TODO_UPDATE_REF) {
 		item->commit = NULL;
 		item->arg_offset = bol - buf;
 		item->arg_len = (int)(eol - bol);
@@ -3712,7 +3753,7 @@
 	init_checkout_metadata(&unpack_tree_opts.meta, name, &oid, NULL);
 
 	if (repo_read_index_unmerged(r)) {
-		ret = error_resolve_conflict(_(action_name(opts)));
+		ret = error_resolve_conflict(action_name(opts));
 		goto cleanup;
 	}
 
@@ -4081,6 +4122,221 @@
 	return ret;
 }
 
+static int write_update_refs_state(struct string_list *refs_to_oids)
+{
+	int result = 0;
+	struct lock_file lock = LOCK_INIT;
+	FILE *fp = NULL;
+	struct string_list_item *item;
+	char *path;
+
+	if (!refs_to_oids->nr)
+		return 0;
+
+	path = rebase_path_update_refs(the_repository->gitdir);
+
+	if (safe_create_leading_directories(path)) {
+		result = error(_("unable to create leading directories of %s"),
+			       path);
+		goto cleanup;
+	}
+
+	if (hold_lock_file_for_update(&lock, path, 0) < 0) {
+		result = error(_("another 'rebase' process appears to be running; "
+				 "'%s.lock' already exists"),
+			       path);
+		goto cleanup;
+	}
+
+	fp = fdopen_lock_file(&lock, "w");
+	if (!fp) {
+		result = error_errno(_("could not open '%s' for writing"), path);
+		rollback_lock_file(&lock);
+		goto cleanup;
+	}
+
+	for_each_string_list_item(item, refs_to_oids) {
+		struct update_ref_record *rec = item->util;
+		fprintf(fp, "%s\n%s\n%s\n", item->string,
+			oid_to_hex(&rec->before), oid_to_hex(&rec->after));
+	}
+
+	result = commit_lock_file(&lock);
+
+cleanup:
+	free(path);
+	return result;
+}
+
+/*
+ * Parse the update-refs file for the current rebase, then remove the
+ * refs that do not appear in the todo_list (and have not had updated
+ * values stored) and add refs that are in the todo_list but not
+ * represented in the update-refs file.
+ *
+ * If there are changes to the update-refs list, then write the new state
+ * to disk.
+ */
+void todo_list_filter_update_refs(struct repository *r,
+				  struct todo_list *todo_list)
+{
+	int i;
+	int updated = 0;
+	struct string_list update_refs = STRING_LIST_INIT_DUP;
+
+	sequencer_get_update_refs_state(r->gitdir, &update_refs);
+
+	/*
+	 * For each item in the update_refs list, if it has no updated
+	 * value and does not appear in the todo_list, then remove it
+	 * from the update_refs list.
+	 */
+	for (i = 0; i < update_refs.nr; i++) {
+		int j;
+		int found = 0;
+		const char *ref = update_refs.items[i].string;
+		size_t reflen = strlen(ref);
+		struct update_ref_record *rec = update_refs.items[i].util;
+
+		/* OID already stored as updated. */
+		if (!is_null_oid(&rec->after))
+			continue;
+
+		for (j = 0; !found && j < todo_list->total_nr; j++) {
+			struct todo_item *item = &todo_list->items[j];
+			const char *arg = todo_list->buf.buf + item->arg_offset;
+
+			if (item->command != TODO_UPDATE_REF)
+				continue;
+
+			if (item->arg_len != reflen ||
+			    strncmp(arg, ref, reflen))
+				continue;
+
+			found = 1;
+		}
+
+		if (!found) {
+			free(update_refs.items[i].string);
+			free(update_refs.items[i].util);
+
+			update_refs.nr--;
+			MOVE_ARRAY(update_refs.items + i, update_refs.items + i + 1, update_refs.nr - i);
+
+			updated = 1;
+			i--;
+		}
+	}
+
+	/*
+	 * For each todo_item, check if its ref is in the update_refs list.
+	 * If not, then add it as an un-updated ref.
+	 */
+	for (i = 0; i < todo_list->total_nr; i++) {
+		struct todo_item *item = &todo_list->items[i];
+		const char *arg = todo_list->buf.buf + item->arg_offset;
+		int j, found = 0;
+
+		if (item->command != TODO_UPDATE_REF)
+			continue;
+
+		for (j = 0; !found && j < update_refs.nr; j++) {
+			const char *ref = update_refs.items[j].string;
+
+			found = strlen(ref) == item->arg_len &&
+				!strncmp(ref, arg, item->arg_len);
+		}
+
+		if (!found) {
+			struct string_list_item *inserted;
+			struct strbuf argref = STRBUF_INIT;
+
+			strbuf_add(&argref, arg, item->arg_len);
+			inserted = string_list_insert(&update_refs, argref.buf);
+			inserted->util = init_update_ref_record(argref.buf);
+			strbuf_release(&argref);
+			updated = 1;
+		}
+	}
+
+	if (updated)
+		write_update_refs_state(&update_refs);
+	string_list_clear(&update_refs, 1);
+}
+
+static int do_update_ref(struct repository *r, const char *refname)
+{
+	struct string_list_item *item;
+	struct string_list list = STRING_LIST_INIT_DUP;
+
+	if (sequencer_get_update_refs_state(r->gitdir, &list))
+		return -1;
+
+	for_each_string_list_item(item, &list) {
+		if (!strcmp(item->string, refname)) {
+			struct update_ref_record *rec = item->util;
+			if (read_ref("HEAD", &rec->after))
+				return -1;
+			break;
+		}
+	}
+
+	write_update_refs_state(&list);
+	string_list_clear(&list, 1);
+	return 0;
+}
+
+static int do_update_refs(struct repository *r, int quiet)
+{
+	int res = 0;
+	struct string_list_item *item;
+	struct string_list refs_to_oids = STRING_LIST_INIT_DUP;
+	struct ref_store *refs = get_main_ref_store(r);
+	struct strbuf update_msg = STRBUF_INIT;
+	struct strbuf error_msg = STRBUF_INIT;
+
+	if ((res = sequencer_get_update_refs_state(r->gitdir, &refs_to_oids)))
+		return res;
+
+	for_each_string_list_item(item, &refs_to_oids) {
+		struct update_ref_record *rec = item->util;
+		int loop_res;
+
+		loop_res = refs_update_ref(refs, "rewritten during rebase",
+					   item->string,
+					   &rec->after, &rec->before,
+					   0, UPDATE_REFS_MSG_ON_ERR);
+		res |= loop_res;
+
+		if (quiet)
+			continue;
+
+		if (loop_res)
+			strbuf_addf(&error_msg, "\t%s\n", item->string);
+		else
+			strbuf_addf(&update_msg, "\t%s\n", item->string);
+	}
+
+	if (!quiet &&
+	    (update_msg.len || error_msg.len)) {
+		fprintf(stderr,
+			_("Updated the following refs with %s:\n%s"),
+			"--update-refs",
+			update_msg.buf);
+
+		if (res)
+			fprintf(stderr,
+				_("Failed to update the following refs with %s:\n%s"),
+				"--update-refs",
+				error_msg.buf);
+	}
+
+	string_list_clear(&refs_to_oids, 1);
+	strbuf_release(&update_msg);
+	strbuf_release(&error_msg);
+	return res;
+}
+
 static int is_final_fixup(struct todo_list *todo_list)
 {
 	int i = todo_list->current;
@@ -4456,6 +4712,12 @@
 				return error_with_patch(r, item->commit,
 							arg, item->arg_len,
 							opts, res, 0);
+		} else if (item->command == TODO_UPDATE_REF) {
+			struct strbuf ref = STRBUF_INIT;
+			strbuf_add(&ref, arg, item->arg_len);
+			if ((res = do_update_ref(r, ref.buf)))
+				reschedule = 1;
+			strbuf_release(&ref);
 		} else if (!is_noop(item->command))
 			return error(_("unknown command %d"), item->command);
 
@@ -4591,6 +4853,9 @@
 
 		strbuf_release(&buf);
 		strbuf_release(&head_ref);
+
+		if (do_update_refs(r, opts->quiet))
+			return -1;
 	}
 
 	/*
@@ -4989,7 +5254,8 @@
 	char label[FLEX_ARRAY];
 };
 
-static int labels_cmp(const void *fndata, const struct hashmap_entry *eptr,
+static int labels_cmp(const void *fndata UNUSED,
+		      const struct hashmap_entry *eptr,
 		      const struct hashmap_entry *entry_or_key, const void *key)
 {
 	const struct labels_entry *a, *b;
@@ -5638,10 +5904,135 @@
 	return 0;
 }
 
+struct todo_add_branch_context {
+	struct todo_item *items;
+	size_t items_nr;
+	size_t items_alloc;
+	struct strbuf *buf;
+	struct commit *commit;
+	struct string_list refs_to_oids;
+};
+
+static int add_decorations_to_list(const struct commit *commit,
+				   struct todo_add_branch_context *ctx)
+{
+	const struct name_decoration *decoration = get_name_decoration(&commit->object);
+	const char *head_ref = resolve_ref_unsafe("HEAD",
+						  RESOLVE_REF_READING,
+						  NULL,
+						  NULL);
+
+	while (decoration) {
+		struct todo_item *item;
+		const char *path;
+		size_t base_offset = ctx->buf->len;
+
+		/*
+		 * If the branch is the current HEAD, then it will be
+		 * updated by the default rebase behavior.
+		 */
+		if (head_ref && !strcmp(head_ref, decoration->name)) {
+			decoration = decoration->next;
+			continue;
+		}
+
+		ALLOC_GROW(ctx->items,
+			ctx->items_nr + 1,
+			ctx->items_alloc);
+		item = &ctx->items[ctx->items_nr];
+		memset(item, 0, sizeof(*item));
+
+		/* If the branch is checked out, then leave a comment instead. */
+		if ((path = branch_checked_out(decoration->name))) {
+			item->command = TODO_COMMENT;
+			strbuf_addf(ctx->buf, "# Ref %s checked out at '%s'\n",
+				    decoration->name, path);
+		} else {
+			struct string_list_item *sti;
+			item->command = TODO_UPDATE_REF;
+			strbuf_addf(ctx->buf, "%s\n", decoration->name);
+
+			sti = string_list_insert(&ctx->refs_to_oids,
+						 decoration->name);
+			sti->util = init_update_ref_record(decoration->name);
+		}
+
+		item->offset_in_buf = base_offset;
+		item->arg_offset = base_offset;
+		item->arg_len = ctx->buf->len - base_offset;
+		ctx->items_nr++;
+
+		decoration = decoration->next;
+	}
+
+	return 0;
+}
+
+/*
+ * For each 'pick' command, find out if the commit has a decoration in
+ * refs/heads/. If so, then add a 'label for-update-refs/' command.
+ */
+static int todo_list_add_update_ref_commands(struct todo_list *todo_list)
+{
+	int i, res;
+	static struct string_list decorate_refs_exclude = STRING_LIST_INIT_NODUP;
+	static struct string_list decorate_refs_exclude_config = STRING_LIST_INIT_NODUP;
+	static struct string_list decorate_refs_include = STRING_LIST_INIT_NODUP;
+	struct decoration_filter decoration_filter = {
+		.include_ref_pattern = &decorate_refs_include,
+		.exclude_ref_pattern = &decorate_refs_exclude,
+		.exclude_ref_config_pattern = &decorate_refs_exclude_config,
+	};
+	struct todo_add_branch_context ctx = {
+		.buf = &todo_list->buf,
+		.refs_to_oids = STRING_LIST_INIT_DUP,
+	};
+
+	ctx.items_alloc = 2 * todo_list->nr + 1;
+	ALLOC_ARRAY(ctx.items, ctx.items_alloc);
+
+	string_list_append(&decorate_refs_include, "refs/heads/");
+	load_ref_decorations(&decoration_filter, 0);
+
+	for (i = 0; i < todo_list->nr; ) {
+		struct todo_item *item = &todo_list->items[i];
+
+		/* insert ith item into new list */
+		ALLOC_GROW(ctx.items,
+			   ctx.items_nr + 1,
+			   ctx.items_alloc);
+
+		ctx.items[ctx.items_nr++] = todo_list->items[i++];
+
+		if (item->commit) {
+			ctx.commit = item->commit;
+			add_decorations_to_list(item->commit, &ctx);
+		}
+	}
+
+	res = write_update_refs_state(&ctx.refs_to_oids);
+
+	string_list_clear(&ctx.refs_to_oids, 1);
+
+	if (res) {
+		/* we failed, so clean up the new list. */
+		free(ctx.items);
+		return res;
+	}
+
+	free(todo_list->items);
+	todo_list->items = ctx.items;
+	todo_list->nr = ctx.items_nr;
+	todo_list->alloc = ctx.items_alloc;
+
+	return 0;
+}
+
 int complete_action(struct repository *r, struct replay_opts *opts, unsigned flags,
 		    const char *shortrevisions, const char *onto_name,
 		    struct commit *onto, const struct object_id *orig_head,
 		    struct string_list *commands, unsigned autosquash,
+		    unsigned update_refs,
 		    struct todo_list *todo_list)
 {
 	char shortonto[GIT_MAX_HEXSZ + 1];
@@ -5660,6 +6051,9 @@
 		item->arg_len = item->arg_offset = item->flags = item->offset_in_buf = 0;
 	}
 
+	if (update_refs && todo_list_add_update_ref_commands(todo_list))
+		return -1;
+
 	if (autosquash && todo_list_rearrange_squash(todo_list))
 		return -1;
 
@@ -5738,7 +6132,7 @@
 	char subject[FLEX_ARRAY];
 };
 
-static int subject2item_cmp(const void *fndata,
+static int subject2item_cmp(const void *fndata UNUSED,
 			    const struct hashmap_entry *eptr,
 			    const struct hashmap_entry *entry_or_key,
 			    const void *key)
@@ -5936,3 +6330,54 @@
 
 	return 0;
 }
+
+int sequencer_get_update_refs_state(const char *wt_dir,
+				    struct string_list *refs)
+{
+	int result = 0;
+	FILE *fp = NULL;
+	struct strbuf ref = STRBUF_INIT;
+	struct strbuf hash = STRBUF_INIT;
+	struct update_ref_record *rec = NULL;
+
+	char *path = rebase_path_update_refs(wt_dir);
+
+	fp = fopen(path, "r");
+	if (!fp)
+		goto cleanup;
+
+	while (strbuf_getline(&ref, fp) != EOF) {
+		struct string_list_item *item;
+
+		CALLOC_ARRAY(rec, 1);
+
+		if (strbuf_getline(&hash, fp) == EOF ||
+		    get_oid_hex(hash.buf, &rec->before)) {
+			warning(_("update-refs file at '%s' is invalid"),
+				  path);
+			result = -1;
+			goto cleanup;
+		}
+
+		if (strbuf_getline(&hash, fp) == EOF ||
+		    get_oid_hex(hash.buf, &rec->after)) {
+			warning(_("update-refs file at '%s' is invalid"),
+				  path);
+			result = -1;
+			goto cleanup;
+		}
+
+		item = string_list_insert(refs, ref.buf);
+		item->util = rec;
+		rec = NULL;
+	}
+
+cleanup:
+	if (fp)
+		fclose(fp);
+	free(path);
+	free(rec);
+	strbuf_release(&ref);
+	strbuf_release(&hash);
+	return result;
+}
diff --git a/sequencer.h b/sequencer.h
index 698599f..563fe59 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -96,6 +96,7 @@
 	TODO_LABEL,
 	TODO_RESET,
 	TODO_MERGE,
+	TODO_UPDATE_REF,
 	/* commands that do nothing but are counted for reporting progress */
 	TODO_NOOP,
 	TODO_DROP,
@@ -132,6 +133,18 @@
 const char *todo_item_get_arg(struct todo_list *todo_list,
 			      struct todo_item *item);
 
+/*
+ * Parse the update-refs file for the current rebase, then remove the
+ * refs that do not appear in the todo_list (and have not had updated
+ * values stored) and add refs that are in the todo_list but not
+ * represented in the update-refs file.
+ *
+ * If there are changes to the update-refs list, then write the new state
+ * to disk.
+ */
+void todo_list_filter_update_refs(struct repository *r,
+				  struct todo_list *todo_list);
+
 /* Call this to setup defaults before parsing command line options */
 void sequencer_init_config(struct replay_opts *opts);
 int sequencer_pick_revisions(struct repository *repo,
@@ -167,6 +180,7 @@
 		    const char *shortrevisions, const char *onto_name,
 		    struct commit *onto, const struct object_id *orig_head,
 		    struct string_list *commands, unsigned autosquash,
+		    unsigned update_refs,
 		    struct todo_list *todo_list);
 int todo_list_rearrange_squash(struct todo_list *todo_list);
 
@@ -233,4 +247,13 @@
 int sequencer_get_last_command(struct repository* r,
 			       enum replay_action *action);
 int sequencer_determine_whence(struct repository *r, enum commit_whence *whence);
+
+/**
+ * Append the set of ref-OID pairs that are currently stored for the 'git
+ * rebase --update-refs' feature if such a rebase is currently happening.
+ *
+ * Localized to a worktree's git dir.
+ */
+int sequencer_get_update_refs_state(const char *wt_dir, struct string_list *refs);
+
 #endif /* SEQUENCER_H */
diff --git a/server-info.c b/server-info.c
index 7701d7c..0ec6c0c 100644
--- a/server-info.c
+++ b/server-info.c
@@ -147,7 +147,8 @@
 }
 
 static int add_info_ref(const char *path, const struct object_id *oid,
-			int flag, void *cb_data)
+			int flag UNUSED,
+			void *cb_data)
 {
 	struct update_info_ctx *uic = cb_data;
 	struct object *o = parse_object(the_repository, oid);
diff --git a/setup.c b/setup.c
index 640f6ea..cefd5f6 100644
--- a/setup.c
+++ b/setup.c
@@ -10,6 +10,10 @@
 static int inside_git_dir = -1;
 static int inside_work_tree = -1;
 static int work_tree_config_is_bogus;
+enum allowed_bare_repo {
+	ALLOWED_BARE_REPO_EXPLICIT = 0,
+	ALLOWED_BARE_REPO_ALL,
+};
 
 static struct startup_info the_startup_info;
 struct startup_info *startup_info = &the_startup_info;
@@ -1156,11 +1160,51 @@
 	 * constant regardless of what failed above. data.is_safe should be
 	 * initialized to false, and might be changed by the callback.
 	 */
-	read_very_early_config(safe_directory_cb, &data);
+	git_protected_config(safe_directory_cb, &data);
 
 	return data.is_safe;
 }
 
+static int allowed_bare_repo_cb(const char *key, const char *value, void *d)
+{
+	enum allowed_bare_repo *allowed_bare_repo = d;
+
+	if (strcasecmp(key, "safe.bareRepository"))
+		return 0;
+
+	if (!strcmp(value, "explicit")) {
+		*allowed_bare_repo = ALLOWED_BARE_REPO_EXPLICIT;
+		return 0;
+	}
+	if (!strcmp(value, "all")) {
+		*allowed_bare_repo = ALLOWED_BARE_REPO_ALL;
+		return 0;
+	}
+	return -1;
+}
+
+static enum allowed_bare_repo get_allowed_bare_repo(void)
+{
+	enum allowed_bare_repo result = ALLOWED_BARE_REPO_ALL;
+	git_protected_config(allowed_bare_repo_cb, &result);
+	return result;
+}
+
+static const char *allowed_bare_repo_to_string(
+	enum allowed_bare_repo allowed_bare_repo)
+{
+	switch (allowed_bare_repo) {
+	case ALLOWED_BARE_REPO_EXPLICIT:
+		return "explicit";
+	case ALLOWED_BARE_REPO_ALL:
+		return "all";
+	default:
+		BUG("invalid allowed_bare_repo %d",
+		    allowed_bare_repo);
+	}
+	return NULL;
+}
+
 enum discovery_result {
 	GIT_DIR_NONE = 0,
 	GIT_DIR_EXPLICIT,
@@ -1170,7 +1214,8 @@
 	GIT_DIR_HIT_CEILING = -1,
 	GIT_DIR_HIT_MOUNT_POINT = -2,
 	GIT_DIR_INVALID_GITFILE = -3,
-	GIT_DIR_INVALID_OWNERSHIP = -4
+	GIT_DIR_INVALID_OWNERSHIP = -4,
+	GIT_DIR_DISALLOWED_BARE = -5,
 };
 
 /*
@@ -1300,6 +1345,8 @@
 		}
 
 		if (is_git_directory(dir->buf)) {
+			if (get_allowed_bare_repo() == ALLOWED_BARE_REPO_EXPLICIT)
+				return GIT_DIR_DISALLOWED_BARE;
 			if (!ensure_valid_ownership(NULL, NULL, dir->buf, report))
 				return GIT_DIR_INVALID_OWNERSHIP;
 			strbuf_addstr(gitdir, ".");
@@ -1448,6 +1495,14 @@
 		}
 		*nongit_ok = 1;
 		break;
+	case GIT_DIR_DISALLOWED_BARE:
+		if (!nongit_ok) {
+			die(_("cannot use bare repository '%s' (safe.bareRepository is '%s')"),
+			    dir.buf,
+			    allowed_bare_repo_to_string(get_allowed_bare_repo()));
+		}
+		*nongit_ok = 1;
+		break;
 	case GIT_DIR_NONE:
 		/*
 		 * As a safeguard against setup_git_directory_gently_1 returning
diff --git a/sha256/nettle.h b/sha256/nettle.h
new file mode 100644
index 0000000..b63e1c8
--- /dev/null
+++ b/sha256/nettle.h
@@ -0,0 +1,31 @@
+#ifndef SHA256_NETTLE_H
+#define SHA256_NETTLE_H
+
+#include <nettle/sha2.h>
+
+typedef struct sha256_ctx nettle_SHA256_CTX;
+
+static inline void nettle_SHA256_Init(nettle_SHA256_CTX *ctx)
+{
+	sha256_init(ctx);
+}
+
+static inline void nettle_SHA256_Update(nettle_SHA256_CTX *ctx,
+					const void *data,
+					size_t len)
+{
+	sha256_update(ctx, len, data);
+}
+
+static inline void nettle_SHA256_Final(unsigned char *digest,
+				       nettle_SHA256_CTX *ctx)
+{
+	sha256_digest(ctx, SHA256_DIGEST_SIZE, digest);
+}
+
+#define platform_SHA256_CTX nettle_SHA256_CTX
+#define platform_SHA256_Init nettle_SHA256_Init
+#define platform_SHA256_Update nettle_SHA256_Update
+#define platform_SHA256_Final nettle_SHA256_Final
+
+#endif
diff --git a/shallow.c b/shallow.c
index 8cb768e..17f9bcd 100644
--- a/shallow.c
+++ b/shallow.c
@@ -604,8 +604,10 @@
 	free(tmp);
 }
 
-static int mark_uninteresting(const char *refname, const struct object_id *oid,
-			      int flags, void *cb_data)
+static int mark_uninteresting(const char *refname UNUSED,
+			      const struct object_id *oid,
+			      int flags UNUSED,
+			      void *cb_data UNUSED)
 {
 	struct commit *commit = lookup_commit_reference_gently(the_repository,
 							       oid, 1);
@@ -715,8 +717,10 @@
 	int nr, alloc;
 };
 
-static int add_ref(const char *refname, const struct object_id *oid,
-		   int flags, void *cb_data)
+static int add_ref(const char *refname UNUSED,
+		   const struct object_id *oid,
+		   int flags UNUSED,
+		   void *cb_data)
 {
 	struct commit_array *ca = cb_data;
 	ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
diff --git a/shared.mak b/shared.mak
index 4330192..33f43ed 100644
--- a/shared.mak
+++ b/shared.mak
@@ -70,6 +70,7 @@
 	QUIET_HDR      = @echo '   ' HDR $(<:hcc=h);
 	QUIET_RC       = @echo '   ' RC $@;
 	QUIET_SPATCH   = @echo '   ' SPATCH $<;
+	QUIET_SPATCH_T = @echo '   ' SPATCH TEST $(@:.build/%=%);
 
 ## Used in "Documentation/Makefile"
 	QUIET_ASCIIDOC	= @echo '   ' ASCIIDOC $@;
diff --git a/strbuf.c b/strbuf.c
index dd9eb85..0890b14 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -436,7 +436,7 @@
 
 size_t strbuf_expand_literal_cb(struct strbuf *sb,
 				const char *placeholder,
-				void *context)
+				void *context UNUSED)
 {
 	int ch;
 
diff --git a/streaming.c b/streaming.c
index fe54665..7b2f8b2 100644
--- a/streaming.c
+++ b/streaming.c
@@ -328,9 +328,9 @@
 }
 
 static int open_istream_pack_non_delta(struct git_istream *st,
-				       struct repository *r,
-				       const struct object_id *oid,
-				       enum object_type *type)
+				       struct repository *r UNUSED,
+				       const struct object_id *oid UNUSED,
+				       enum object_type *type UNUSED)
 {
 	struct pack_window *window;
 	enum object_type in_pack_type;
diff --git a/strmap.c b/strmap.c
index ee48635..c7b9c52 100644
--- a/strmap.c
+++ b/strmap.c
@@ -2,10 +2,10 @@
 #include "strmap.h"
 #include "mem-pool.h"
 
-int cmp_strmap_entry(const void *hashmap_cmp_fn_data,
+int cmp_strmap_entry(const void *hashmap_cmp_fn_data UNUSED,
 		     const struct hashmap_entry *entry1,
 		     const struct hashmap_entry *entry2,
-		     const void *keydata)
+		     const void *keydata UNUSED)
 {
 	const struct strmap_entry *e1, *e2;
 
diff --git a/sub-process.c b/sub-process.c
index cae56ae..6d42322 100644
--- a/sub-process.c
+++ b/sub-process.c
@@ -5,10 +5,10 @@
 #include "sigchain.h"
 #include "pkt-line.h"
 
-int cmd2process_cmp(const void *unused_cmp_data,
+int cmd2process_cmp(const void *cmp_data UNUSED,
 		    const struct hashmap_entry *eptr,
 		    const struct hashmap_entry *entry_or_key,
-		    const void *unused_keydata)
+		    const void *keydata UNUSED)
 {
 	const struct subprocess_entry *e1, *e2;
 
diff --git a/submodule-config.c b/submodule-config.c
index c2ac7e7..cd7ee23 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -38,10 +38,10 @@
 	lookup_path
 };
 
-static int config_path_cmp(const void *unused_cmp_data,
+static int config_path_cmp(const void *cmp_data UNUSED,
 			   const struct hashmap_entry *eptr,
 			   const struct hashmap_entry *entry_or_key,
-			   const void *unused_keydata)
+			   const void *keydata UNUSED)
 {
 	const struct submodule_entry *a, *b;
 
@@ -52,10 +52,10 @@
 	       !oideq(&a->config->gitmodules_oid, &b->config->gitmodules_oid);
 }
 
-static int config_name_cmp(const void *unused_cmp_data,
+static int config_name_cmp(const void *cmp_data UNUSED,
 			   const struct hashmap_entry *eptr,
 			   const struct hashmap_entry *entry_or_key,
-			   const void *unused_keydata)
+			   const void *keydata UNUSED)
 {
 	const struct submodule_entry *a, *b;
 
diff --git a/submodule.c b/submodule.c
index 4e299f5..bf7a2c7 100644
--- a/submodule.c
+++ b/submodule.c
@@ -213,7 +213,8 @@
 }
 
 /* Cheap function that only determines if we're interested in submodules at all */
-int git_default_submodule_config(const char *var, const char *value, void *cb)
+int git_default_submodule_config(const char *var, const char *value,
+				 void *cb UNUSED)
 {
 	if (!strcmp(var, "submodule.recurse")) {
 		int v = git_config_bool(var, value) ?
@@ -415,10 +416,9 @@
 	return 0;
 }
 
-const char *submodule_strategy_to_string(const struct submodule_update_strategy *s)
+const char *submodule_update_type_to_string(enum submodule_update_type type)
 {
-	struct strbuf sb = STRBUF_INIT;
-	switch (s->type) {
+	switch (type) {
 	case SM_UPDATE_CHECKOUT:
 		return "checkout";
 	case SM_UPDATE_MERGE:
@@ -428,12 +428,11 @@
 	case SM_UPDATE_NONE:
 		return "none";
 	case SM_UPDATE_UNSPECIFIED:
-		return NULL;
 	case SM_UPDATE_COMMAND:
-		strbuf_addf(&sb, "!%s", s->command);
-		return strbuf_detach(&sb, NULL);
+		BUG("init_submodule() should handle type %d", type);
+	default:
+		BUG("unexpected update strategy type: %d", type);
 	}
-	return NULL;
 }
 
 void handle_ignore_submodules_arg(struct diff_options *diffopt,
@@ -940,8 +939,9 @@
 	string_list_clear(submodules, 1);
 }
 
-static int has_remote(const char *refname, const struct object_id *oid,
-		      int flags, void *cb_data)
+static int has_remote(const char *refname UNUSED,
+		      const struct object_id *oid UNUSED,
+		      int flags UNUSED, void *cb_data UNUSED)
 {
 	return 1;
 }
@@ -1243,8 +1243,9 @@
 	return ret;
 }
 
-static int append_oid_to_array(const char *ref, const struct object_id *oid,
-			       int flags, void *data)
+static int append_oid_to_array(const char *ref UNUSED,
+			       const struct object_id *oid,
+			       int flags UNUSED, void *data)
 {
 	struct oid_array *array = data;
 	oid_array_append(array, oid);
@@ -2374,7 +2375,7 @@
 		cp.no_stdin = 1;
 		strvec_pushl(&cp.args, "--super-prefix", sb.buf,
 			     "submodule--helper",
-			     "absorb-git-dirs", NULL);
+			     "absorbgitdirs", NULL);
 		prepare_submodule_repo_env(&cp.env);
 		if (run_command(&cp))
 			die(_("could not recurse into submodule '%s'"), path);
@@ -2388,7 +2389,7 @@
 	struct child_process cp = CHILD_PROCESS_INIT;
 	struct strbuf sb = STRBUF_INIT;
 	struct strbuf one_up = STRBUF_INIT;
-	const char *cwd = xgetcwd();
+	char *cwd = xgetcwd();
 	int ret = 0;
 	const char *subpath;
 	int code;
@@ -2451,6 +2452,7 @@
 		ret = 1;
 		free(super_wt);
 	}
+	free(cwd);
 	strbuf_release(&sb);
 
 	code = finish_command(&cp);
diff --git a/submodule.h b/submodule.h
index bfaa9da..6a9fec6 100644
--- a/submodule.h
+++ b/submodule.h
@@ -72,7 +72,7 @@
 enum submodule_update_type parse_submodule_update_type(const char *value);
 int parse_submodule_update_strategy(const char *value,
 				    struct submodule_update_strategy *dst);
-const char *submodule_strategy_to_string(const struct submodule_update_strategy *s);
+const char *submodule_update_type_to_string(enum submodule_update_type type);
 void handle_ignore_submodules_arg(struct diff_options *, const char *);
 void show_submodule_diff_summary(struct diff_options *o, const char *path,
 			    struct object_id *one, struct object_id *two,
diff --git a/t/Makefile b/t/Makefile
index 056ce55..1c80c0c 100644
--- a/t/Makefile
+++ b/t/Makefile
@@ -35,7 +35,6 @@
 CHAINLINTTMP_SQ = $(subst ','\'',$(CHAINLINTTMP))
 
 T = $(sort $(wildcard t[0-9][0-9][0-9][0-9]-*.sh))
-TGITWEB = $(sort $(wildcard t95[0-9][0-9]-*.sh))
 THELPERS = $(sort $(filter-out $(T),$(wildcard *.sh)))
 TPERF = $(sort $(wildcard perf/p[0-9][0-9][0-9][0-9]-*.sh))
 CHAINLINTTESTS = $(sort $(patsubst chainlint/%.test,%,$(wildcard chainlint/*.test)))
@@ -63,7 +62,7 @@
 	$(RM) -r '$(TEST_RESULTS_DIRECTORY_SQ)'
 
 clean-except-prove-cache: clean-chainlint
-	$(RM) -r 'trash directory'.* '$(TEST_RESULTS_DIRECTORY_SQ)'
+	$(RM) -r 'trash directory'.*
 	$(RM) -r valgrind/bin
 
 clean: clean-except-prove-cache
@@ -112,9 +111,6 @@
 		echo "$$f"; \
 	done | '$(SHELL_PATH_SQ)' ./aggregate-results.sh
 
-gitweb-test:
-	$(MAKE) $(TGITWEB)
-
 valgrind:
 	$(MAKE) GIT_TEST_OPTS="$(GIT_TEST_OPTS) --valgrind"
 
diff --git a/t/README b/t/README
index 4f9981c..2f439f9 100644
--- a/t/README
+++ b/t/README
@@ -366,12 +366,47 @@
 GIT_TEST_SPLIT_INDEX=<boolean> forces split-index mode on the whole
 test suite. Accept any boolean values that are accepted by git-config.
 
-GIT_TEST_PASSING_SANITIZE_LEAK=<boolean> when compiled with
-SANITIZE=leak will run only those tests that have whitelisted
-themselves as passing with no memory leaks. Tests can be whitelisted
-by setting "TEST_PASSES_SANITIZE_LEAK=true" before sourcing
-"test-lib.sh" itself at the top of the test script. This test mode is
-used by the "linux-leaks" CI target.
+GIT_TEST_PASSING_SANITIZE_LEAK=true skips those tests that haven't
+declared themselves as leak-free by setting
+"TEST_PASSES_SANITIZE_LEAK=true" before sourcing "test-lib.sh". This
+test mode is used by the "linux-leaks" CI target.
+
+GIT_TEST_PASSING_SANITIZE_LEAK=check checks that our
+"TEST_PASSES_SANITIZE_LEAK=true" markings are current. Rather than
+skipping those tests that haven't set "TEST_PASSES_SANITIZE_LEAK=true"
+before sourcing "test-lib.sh" this mode runs them with
+"--invert-exit-code". This is used to check that there's a one-to-one
+mapping between "TEST_PASSES_SANITIZE_LEAK=true" and those tests that
+pass under "SANITIZE=leak". This is especially useful when testing a
+series that fixes various memory leaks with "git rebase -x".
+
+GIT_TEST_SANITIZE_LEAK_LOG=true will log memory leaks to
+"test-results/$TEST_NAME.leak/trace.*" files. The logs include a
+"dedup_token" (see +"ASAN_OPTIONS=help=1 ./git") and other options to
+make logs +machine-readable.
+
+With GIT_TEST_SANITIZE_LEAK_LOG=true we'll look at the leak logs
+before exiting and exit on failure if the logs showed that we had a
+memory leak, even if the test itself would have otherwise passed. This
+allows us to catch e.g. missing &&-chaining. This is especially useful
+when combined with "GIT_TEST_PASSING_SANITIZE_LEAK", see below.
+
+GIT_TEST_PASSING_SANITIZE_LEAK=check when combined with "--immediate"
+will run to completion faster, and result in the same failing
+tests. The only practical reason to run
+GIT_TEST_PASSING_SANITIZE_LEAK=check without "--immediate" is to
+combine it with "GIT_TEST_SANITIZE_LEAK_LOG=true". If we stop at the
+first failing test case our leak logs won't show subsequent leaks we
+might have run into.
+
+GIT_TEST_PASSING_SANITIZE_LEAK=(true|check) will not catch all memory
+leaks unless combined with GIT_TEST_SANITIZE_LEAK_LOG=true. Some tests
+run "git" (or "test-tool" etc.) without properly checking the exit
+code, or git will invoke itself and fail to ferry the abort() exit
+code to the original caller. When the two modes are combined we'll
+look at the "test-results/$TEST_NAME.leak/trace.*" files at the end of
+the test run to see if had memory leaks which the test itself didn't
+catch.
 
 GIT_TEST_PROTOCOL_VERSION=<n>, when set, makes 'protocol.version'
 default to n.
@@ -935,32 +970,6 @@
 	    test_done
 	fi
 
- - test_external [<prereq>] <message> <external> <script>
-
-   Execute a <script> with an <external> interpreter (like perl). This
-   was added for tests like t9700-perl-git.sh which do most of their
-   work in an external test script.
-
-	test_external \
-	    'GitwebCache::*FileCache*' \
-	    perl "$TEST_DIRECTORY"/t9503/test_cache_interface.pl
-
-   If the test is outputting its own TAP you should set the
-   test_external_has_tap variable somewhere before calling the first
-   test_external* function. See t9700-perl-git.sh for an example.
-
-	# The external test will outputs its own plan
-	test_external_has_tap=1
-
- - test_external_without_stderr [<prereq>] <message> <external> <script>
-
-   Like test_external but fail if there's any output on stderr,
-   instead of checking the exit code.
-
-	test_external_without_stderr \
-	    'Perl API' \
-	    perl "$TEST_DIRECTORY"/t9700/test.pl
-
  - test_expect_code <exit-code> <command>
 
    Run a command and ensure that it exits with the given exit code.
diff --git a/t/annotate-tests.sh b/t/annotate-tests.sh
index cc01d89..f1b9a6c 100644
--- a/t/annotate-tests.sh
+++ b/t/annotate-tests.sh
@@ -153,7 +153,7 @@
 
 test_expect_success 'blame huge graft' '
 	test_when_finished "git checkout branch2" &&
-	test_when_finished "rm -f .git/info/grafts" &&
+	test_when_finished "rm -rf .git/info" &&
 	graft= &&
 	for i in 0 1 2
 	do
@@ -168,6 +168,7 @@
 			graft="$graft$commit " || return 1
 		done
 	done &&
+	mkdir .git/info &&
 	printf "%s " $graft >.git/info/grafts &&
 	check_count -h 00 01 1 10 1
 '
diff --git a/t/helper/test-bloom.c b/t/helper/test-bloom.c
index ad3ef1c..6c900ca 100644
--- a/t/helper/test-bloom.c
+++ b/t/helper/test-bloom.c
@@ -16,6 +16,7 @@
 		}
 		printf("\n");
 		add_key_to_filter(&key, filter, &settings);
+		clear_bloom_key(&key);
 }
 
 static void print_bloom_filter(struct bloom_filter *filter) {
@@ -80,6 +81,7 @@
 		}
 
 		print_bloom_filter(&filter);
+		free(filter.data);
 	}
 
 	if (!strcmp(argv[1], "get_filter_for_commit")) {
diff --git a/t/helper/test-config.c b/t/helper/test-config.c
index a6e9367..4ba9eb6 100644
--- a/t/helper/test-config.c
+++ b/t/helper/test-config.c
@@ -37,7 +37,7 @@
  *
  */
 
-static int iterate_cb(const char *var, const char *value, void *data)
+static int iterate_cb(const char *var, const char *value, void *data UNUSED)
 {
 	static int nr;
 
diff --git a/t/helper/test-crontab.c b/t/helper/test-crontab.c
index e7c0137..e6c1b1e 100644
--- a/t/helper/test-crontab.c
+++ b/t/helper/test-crontab.c
@@ -2,33 +2,34 @@
 #include "cache.h"
 
 /*
- * Usage: test-tool cron <file> [-l]
+ * Usage: test-tool crontab <file> -l|<input>
  *
  * If -l is specified, then write the contents of <file> to stdout.
- * Otherwise, write from stdin into <file>.
+ * Otherwise, copy the contents of <input> into <file>.
  */
 int cmd__crontab(int argc, const char **argv)
 {
 	int a;
 	FILE *from, *to;
 
-	if (argc == 3 && !strcmp(argv[2], "-l")) {
+	if (argc != 3)
+		usage("test-tool crontab <file> -l|<input>");
+
+	if (!strcmp(argv[2], "-l")) {
 		from = fopen(argv[1], "r");
 		if (!from)
 			return 0;
 		to = stdout;
-	} else if (argc == 2) {
-		from = stdin;
-		to = fopen(argv[1], "w");
-	} else
-		return error("unknown arguments");
+	} else {
+		from = xfopen(argv[2], "r");
+		to = xfopen(argv[1], "w");
+	}
 
 	while ((a = fgetc(from)) != EOF)
 		fputc(a, to);
 
-	if (argc == 3)
-		fclose(from);
-	else
+	fclose(from);
+	if (to != stdout)
 		fclose(to);
 
 	return 0;
diff --git a/t/helper/test-delta.c b/t/helper/test-delta.c
index e749a49..b15481e 100644
--- a/t/helper/test-delta.c
+++ b/t/helper/test-delta.c
@@ -20,8 +20,9 @@
 {
 	int fd;
 	struct stat st;
-	void *from_buf, *data_buf, *out_buf;
+	void *from_buf = NULL, *data_buf = NULL, *out_buf = NULL;
 	unsigned long from_size, data_size, out_size;
+	int ret = 1;
 
 	if (argc != 5 || (strcmp(argv[1], "-d") && strcmp(argv[1], "-p"))) {
 		fprintf(stderr, "usage: %s\n", usage_str);
@@ -38,21 +39,21 @@
 	if (read_in_full(fd, from_buf, from_size) < 0) {
 		perror(argv[2]);
 		close(fd);
-		return 1;
+		goto cleanup;
 	}
 	close(fd);
 
 	fd = open(argv[3], O_RDONLY);
 	if (fd < 0 || fstat(fd, &st)) {
 		perror(argv[3]);
-		return 1;
+		goto cleanup;
 	}
 	data_size = st.st_size;
 	data_buf = xmalloc(data_size);
 	if (read_in_full(fd, data_buf, data_size) < 0) {
 		perror(argv[3]);
 		close(fd);
-		return 1;
+		goto cleanup;
 	}
 	close(fd);
 
@@ -66,14 +67,20 @@
 				      &out_size);
 	if (!out_buf) {
 		fprintf(stderr, "delta operation failed (returned NULL)\n");
-		return 1;
+		goto cleanup;
 	}
 
 	fd = open (argv[4], O_WRONLY|O_CREAT|O_TRUNC, 0666);
 	if (fd < 0 || write_in_full(fd, out_buf, out_size) < 0) {
 		perror(argv[4]);
-		return 1;
+		goto cleanup;
 	}
 
-	return 0;
+	ret = 0;
+cleanup:
+	free(from_buf);
+	free(data_buf);
+	free(out_buf);
+
+	return ret;
 }
diff --git a/t/helper/test-dump-cache-tree.c b/t/helper/test-dump-cache-tree.c
index 6a3f88f..0d6d7f1 100644
--- a/t/helper/test-dump-cache-tree.c
+++ b/t/helper/test-dump-cache-tree.c
@@ -59,11 +59,16 @@
 {
 	struct index_state istate;
 	struct cache_tree *another = cache_tree();
+	int ret;
+
 	setup_git_directory();
 	if (read_cache() < 0)
 		die("unable to read index file");
 	istate = the_index;
 	istate.cache_tree = another;
 	cache_tree_update(&istate, WRITE_TREE_DRY_RUN);
-	return dump_cache_tree(active_cache_tree, another, "");
+	ret = dump_cache_tree(active_cache_tree, another, "");
+	cache_tree_free(&another);
+
+	return ret;
 }
diff --git a/t/helper/test-fast-rebase.c b/t/helper/test-fast-rebase.c
index 4e5553e..45665ec 100644
--- a/t/helper/test-fast-rebase.c
+++ b/t/helper/test-fast-rebase.c
@@ -184,8 +184,6 @@
 		last_picked_commit = commit;
 		last_commit = create_commit(result.tree, commit, last_commit);
 	}
-	/* TODO: There should be some kind of rev_info_free(&revs) call... */
-	memset(&revs, 0, sizeof(revs));
 
 	merge_switch_to_result(&merge_opt, head_tree, &result, 1, !result.clean);
 
diff --git a/t/helper/test-hash.c b/t/helper/test-hash.c
index 261c545..5860dab 100644
--- a/t/helper/test-hash.c
+++ b/t/helper/test-hash.c
@@ -54,5 +54,6 @@
 		fwrite(hash, 1, algop->rawsz, stdout);
 	else
 		puts(hash_to_hex_algop(hash, algop));
+	free(buffer);
 	return 0;
 }
diff --git a/t/helper/test-json-writer.c b/t/helper/test-json-writer.c
index 37c4525..8c3edac 100644
--- a/t/helper/test-json-writer.c
+++ b/t/helper/test-json-writer.c
@@ -181,12 +181,18 @@
 
 static void make_nest1(int pretty)
 {
+	make_obj1(0);
+	make_arr1(0);
+
 	jw_object_begin(&nest1, pretty);
 	{
 		jw_object_sub_jw(&nest1, "obj1", &obj1);
 		jw_object_sub_jw(&nest1, "arr1", &arr1);
 	}
 	jw_end(&nest1);
+
+	jw_release(&obj1);
+	jw_release(&arr1);
 }
 
 static char *expect_inline1 =
@@ -313,6 +319,9 @@
 		jw_object_sub_jw(&mixed1, "arr1", &arr1);
 	}
 	jw_end(&mixed1);
+
+	jw_release(&obj1);
+	jw_release(&arr1);
 }
 
 static void cmp(const char *test, const struct json_writer *jw, const char *exp)
@@ -325,8 +334,8 @@
 	exit(1);
 }
 
-#define t(v) do { make_##v(0); cmp(#v, &v, expect_##v); } while (0)
-#define p(v) do { make_##v(1); cmp(#v, &v, pretty_##v); } while (0)
+#define t(v) do { make_##v(0); cmp(#v, &v, expect_##v); jw_release(&v); } while (0)
+#define p(v) do { make_##v(1); cmp(#v, &v, pretty_##v); jw_release(&v); } while (0)
 
 /*
  * Run some basic regression tests with some known patterns.
@@ -381,7 +390,6 @@
 
 	/* mixed forms */
 	t(mixed1);
-	jw_init(&mixed1);
 	p(mixed1);
 
 	return 0;
@@ -544,7 +552,7 @@
 
 	printf("%s\n", jw.json.buf);
 
-	strbuf_release(&jw.json);
+	jw_release(&jw);
 	return 0;
 }
 
diff --git a/t/helper/test-mergesort.c b/t/helper/test-mergesort.c
index ebf68f7..335e5bb 100644
--- a/t/helper/test-mergesort.c
+++ b/t/helper/test-mergesort.c
@@ -13,41 +13,46 @@
 	struct line *next;
 };
 
-static void *get_next(const void *a)
-{
-	return ((const struct line *)a)->next;
-}
+DEFINE_LIST_SORT(static, sort_lines, struct line, next);
 
-static void set_next(void *a, void *b)
+static int compare_strings(const struct line *x, const struct line *y)
 {
-	((struct line *)a)->next = b;
-}
-
-static int compare_strings(const void *a, const void *b)
-{
-	const struct line *x = a, *y = b;
 	return strcmp(x->text, y->text);
 }
 
 static int sort_stdin(void)
 {
-	struct line *line, *p = NULL, *lines = NULL;
+	struct line *lines;
+	struct line **tail = &lines;
 	struct strbuf sb = STRBUF_INIT;
+	struct mem_pool lines_pool;
+	char *p;
 
-	while (!strbuf_getline(&sb, stdin)) {
-		line = xmalloc(sizeof(struct line));
-		line->text = strbuf_detach(&sb, NULL);
-		if (p) {
-			line->next = p->next;
-			p->next = line;
-		} else {
-			line->next = NULL;
-			lines = line;
-		}
-		p = line;
+	strbuf_read(&sb, 0, 0);
+
+	/*
+	 * Split by newline, but don't create an item
+	 * for the empty string after the last separator.
+	 */
+	if (sb.len && sb.buf[sb.len - 1] == '\n')
+		strbuf_setlen(&sb, sb.len - 1);
+
+	mem_pool_init(&lines_pool, 0);
+	p = sb.buf;
+	for (;;) {
+		char *eol = strchr(p, '\n');
+		struct line *line = mem_pool_alloc(&lines_pool, sizeof(*line));
+		line->text = p;
+		*tail = line;
+		tail = &line->next;
+		if (!eol)
+			break;
+		*eol = '\0';
+		p = eol + 1;
 	}
+	*tail = NULL;
 
-	lines = llist_mergesort(lines, get_next, set_next, compare_strings);
+	sort_lines(&lines, compare_strings);
 
 	while (lines) {
 		puts(lines->text);
@@ -273,21 +278,11 @@
 	struct number *next;
 };
 
-static void *get_next_number(const void *a)
-{
-	stats.get_next++;
-	return ((const struct number *)a)->next;
-}
+DEFINE_LIST_SORT_DEBUG(static, sort_numbers, struct number, next,
+		       stats.get_next++, stats.set_next++);
 
-static void set_next_number(void *a, void *b)
+static int compare_numbers(const struct number *an, const struct number *bn)
 {
-	stats.set_next++;
-	((struct number *)a)->next = b;
-}
-
-static int compare_numbers(const void *av, const void *bv)
-{
-	const struct number *an = av, *bn = bv;
 	int a = an->value, b = bn->value;
 	stats.compare++;
 	return (a > b) - (a < b);
@@ -325,8 +320,7 @@
 	*tail = NULL;
 
 	stats.get_next = stats.set_next = stats.compare = 0;
-	list = llist_mergesort(list, get_next_number, set_next_number,
-			       compare_numbers);
+	sort_numbers(&list, compare_numbers);
 
 	QSORT(arr, n, compare_ints);
 	for (i = 0, curr = list; i < n && curr; i++, curr = curr->next) {
diff --git a/t/helper/test-parse-options.c b/t/helper/test-parse-options.c
index 48d3cf6..5068355 100644
--- a/t/helper/test-parse-options.c
+++ b/t/helper/test-parse-options.c
@@ -192,3 +192,131 @@
 
 	return ret;
 }
+
+static void print_args(int argc, const char **argv)
+{
+	int i;
+	for (i = 0; i < argc; i++)
+		printf("arg %02d: %s\n", i, argv[i]);
+}
+
+static int parse_options_flags__cmd(int argc, const char **argv,
+				    enum parse_opt_flags test_flags)
+{
+	const char *usage[] = {
+		"<...> cmd [options]",
+		NULL
+	};
+	int opt = 0;
+	const struct option options[] = {
+		OPT_INTEGER('o', "opt", &opt, "an integer option"),
+		OPT_END()
+	};
+
+	argc = parse_options(argc, argv, NULL, options, usage, test_flags);
+
+	printf("opt: %d\n", opt);
+	print_args(argc, argv);
+
+	return 0;
+}
+
+static enum parse_opt_flags test_flags = 0;
+static const struct option test_flag_options[] = {
+	OPT_GROUP("flag-options:"),
+	OPT_BIT(0, "keep-dashdash", &test_flags,
+		"pass PARSE_OPT_KEEP_DASHDASH to parse_options()",
+		PARSE_OPT_KEEP_DASHDASH),
+	OPT_BIT(0, "stop-at-non-option", &test_flags,
+		"pass PARSE_OPT_STOP_AT_NON_OPTION to parse_options()",
+		PARSE_OPT_STOP_AT_NON_OPTION),
+	OPT_BIT(0, "keep-argv0", &test_flags,
+		"pass PARSE_OPT_KEEP_ARGV0 to parse_options()",
+		PARSE_OPT_KEEP_ARGV0),
+	OPT_BIT(0, "keep-unknown-opt", &test_flags,
+		"pass PARSE_OPT_KEEP_UNKNOWN_OPT to parse_options()",
+		PARSE_OPT_KEEP_UNKNOWN_OPT),
+	OPT_BIT(0, "no-internal-help", &test_flags,
+		"pass PARSE_OPT_NO_INTERNAL_HELP to parse_options()",
+		PARSE_OPT_NO_INTERNAL_HELP),
+	OPT_BIT(0, "subcommand-optional", &test_flags,
+		"pass PARSE_OPT_SUBCOMMAND_OPTIONAL to parse_options()",
+		PARSE_OPT_SUBCOMMAND_OPTIONAL),
+	OPT_END()
+};
+
+int cmd__parse_options_flags(int argc, const char **argv)
+{
+	const char *usage[] = {
+		"test-tool parse-options-flags [flag-options] cmd [options]",
+		NULL
+	};
+
+	argc = parse_options(argc, argv, NULL, test_flag_options, usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+
+	if (!argc || strcmp(argv[0], "cmd")) {
+		error("'cmd' is mandatory");
+		usage_with_options(usage, test_flag_options);
+	}
+
+	return parse_options_flags__cmd(argc, argv, test_flags);
+}
+
+static int subcmd_one(int argc, const char **argv, const char *prefix)
+{
+	printf("fn: subcmd_one\n");
+	print_args(argc, argv);
+	return 0;
+}
+
+static int subcmd_two(int argc, const char **argv, const char *prefix)
+{
+	printf("fn: subcmd_two\n");
+	print_args(argc, argv);
+	return 0;
+}
+
+static int parse_subcommand__cmd(int argc, const char **argv,
+				 enum parse_opt_flags test_flags)
+{
+	const char *usage[] = {
+		"<...> cmd subcmd-one",
+		"<...> cmd subcmd-two",
+		NULL
+	};
+	parse_opt_subcommand_fn *fn = NULL;
+	int opt = 0;
+	struct option options[] = {
+		OPT_SUBCOMMAND("subcmd-one", &fn, subcmd_one),
+		OPT_SUBCOMMAND("subcmd-two", &fn, subcmd_two),
+		OPT_INTEGER('o', "opt", &opt, "an integer option"),
+		OPT_END()
+	};
+
+	if (test_flags & PARSE_OPT_SUBCOMMAND_OPTIONAL)
+		fn = subcmd_one;
+	argc = parse_options(argc, argv, NULL, options, usage, test_flags);
+
+	printf("opt: %d\n", opt);
+
+	return fn(argc, argv, NULL);
+}
+
+int cmd__parse_subcommand(int argc, const char **argv)
+{
+	const char *usage[] = {
+		"test-tool parse-subcommand [flag-options] cmd <subcommand>",
+		NULL
+	};
+
+	argc = parse_options(argc, argv, NULL, test_flag_options, usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+
+	if (!argc || strcmp(argv[0], "cmd")) {
+		error("'cmd' is mandatory");
+		usage_with_options(usage, test_flag_options);
+	}
+
+	return parse_subcommand__cmd(argc, argv, test_flags);
+}
diff --git a/t/helper/test-path-utils.c b/t/helper/test-path-utils.c
index 229ed41..d20e1b7 100644
--- a/t/helper/test-path-utils.c
+++ b/t/helper/test-path-utils.c
@@ -296,9 +296,8 @@
 	if (argc == 3 && !strcmp(argv[1], "normalize_path_copy")) {
 		char *buf = xmallocz(strlen(argv[2]));
 		int rv = normalize_path_copy(buf, argv[2]);
-		if (rv)
-			buf = "++failed++";
-		puts(buf);
+		puts(rv ? "++failed++" : buf);
+		free(buf);
 		return 0;
 	}
 
@@ -356,7 +355,10 @@
 		int nongit_ok;
 		setup_git_directory_gently(&nongit_ok);
 		while (argc > 3) {
-			puts(prefix_path(prefix, prefix_len, argv[3]));
+			char *pfx = prefix_path(prefix, prefix_len, argv[3]);
+
+			puts(pfx);
+			free(pfx);
 			argc--;
 			argv++;
 		}
@@ -366,6 +368,7 @@
 	if (argc == 4 && !strcmp(argv[1], "strip_path_suffix")) {
 		char *prefix = strip_path_suffix(argv[2], argv[3]);
 		printf("%s\n", prefix ? prefix : "(null)");
+		free(prefix);
 		return 0;
 	}
 
diff --git a/t/helper/test-ref-store.c b/t/helper/test-ref-store.c
index 9646d85..ae8a564 100644
--- a/t/helper/test-ref-store.c
+++ b/t/helper/test-ref-store.c
@@ -96,6 +96,7 @@
 			die("no such worktree: %s", gitdir);
 
 		*refs = get_worktree_ref_store(*p);
+		free_worktrees(worktrees);
 	} else
 		die("unknown backend %s", argv[0]);
 
@@ -160,7 +161,7 @@
 }
 
 static int each_ref(const char *refname, const struct object_id *oid,
-		    int flags, void *cb_data)
+		    int flags, void *cb_data UNUSED)
 {
 	printf("%s %s 0x%x\n", oid_to_hex(oid), refname, flags);
 	return 0;
@@ -206,7 +207,7 @@
 
 static int each_reflog(struct object_id *old_oid, struct object_id *new_oid,
 		       const char *committer, timestamp_t timestamp,
-		       int tz, const char *msg, void *cb_data)
+		       int tz, const char *msg, void *cb_data UNUSED)
 {
 	printf("%s %s %s %" PRItime " %+05d%s%s", oid_to_hex(old_oid),
 	       oid_to_hex(new_oid), committer, timestamp, tz,
diff --git a/t/helper/test-regex.c b/t/helper/test-regex.c
index d6f28ca..bd871a7 100644
--- a/t/helper/test-regex.c
+++ b/t/helper/test-regex.c
@@ -34,6 +34,7 @@
 	if (m[0].rm_so == 3) /* matches '\n' when it should not */
 		die("regex bug confirmed: re-build git with NO_REGEX=1");
 
+	regfree(&r);
 	return 0;
 }
 
@@ -94,18 +95,20 @@
 		die("failed regcomp() for pattern '%s' (%s)", pat, errbuf);
 	}
 	if (!str)
-		return 0;
+		goto cleanup;
 
 	ret = regexec(&r, str, 1, m, 0);
 	if (ret) {
 		if (silent || ret == REG_NOMATCH)
-			return ret;
+			goto cleanup;
 
 		regerror(ret, &r, errbuf, sizeof(errbuf));
 		die("failed regexec() for subject '%s' (%s)", str, errbuf);
 	}
 
-	return 0;
+cleanup:
+	regfree(&r);
+	return ret;
 usage:
 	usage("\ttest-tool regex --bug\n"
 	      "\ttest-tool regex [--silent] <pattern>\n"
diff --git a/t/helper/test-rot13-filter.c b/t/helper/test-rot13-filter.c
new file mode 100644
index 0000000..f8d564c
--- /dev/null
+++ b/t/helper/test-rot13-filter.c
@@ -0,0 +1,382 @@
+/*
+ * Example implementation for the Git filter protocol version 2
+ * See Documentation/gitattributes.txt, section "Filter Protocol"
+ *
+ * Usage: test-tool rot13-filter [--always-delay] --log=<path> <capabilities>
+ *
+ * Log path defines a debug log file that the script writes to. The
+ * subsequent arguments define a list of supported protocol capabilities
+ * ("clean", "smudge", etc).
+ *
+ * When --always-delay is given all pathnames with the "can-delay" flag
+ * that don't appear on the list bellow are delayed with a count of 1
+ * (see more below).
+ *
+ * This implementation supports special test cases:
+ * (1) If data with the pathname "clean-write-fail.r" is processed with
+ *     a "clean" operation then the write operation will die.
+ * (2) If data with the pathname "smudge-write-fail.r" is processed with
+ *     a "smudge" operation then the write operation will die.
+ * (3) If data with the pathname "error.r" is processed with any
+ *     operation then the filter signals that it cannot or does not want
+ *     to process the file.
+ * (4) If data with the pathname "abort.r" is processed with any
+ *     operation then the filter signals that it cannot or does not want
+ *     to process the file and any file after that is processed with the
+ *     same command.
+ * (5) If data with a pathname that is a key in the delay hash is
+ *     requested (e.g. "test-delay10.a") then the filter responds with
+ *     a "delay" status and sets the "requested" field in the delay hash.
+ *     The filter will signal the availability of this object after
+ *     "count" (field in delay hash) "list_available_blobs" commands.
+ * (6) If data with the pathname "missing-delay.a" is processed that the
+ *     filter will drop the path from the "list_available_blobs" response.
+ * (7) If data with the pathname "invalid-delay.a" is processed that the
+ *     filter will add the path "unfiltered" which was not delayed before
+ *     to the "list_available_blobs" response.
+ */
+
+#include "test-tool.h"
+#include "pkt-line.h"
+#include "string-list.h"
+#include "strmap.h"
+#include "parse-options.h"
+
+static FILE *logfile;
+static int always_delay, has_clean_cap, has_smudge_cap;
+static struct strmap delay = STRMAP_INIT;
+
+static inline const char *str_or_null(const char *str)
+{
+	return str ? str : "(null)";
+}
+
+static char *rot13(char *str)
+{
+	char *c;
+	for (c = str; *c; c++)
+		if (isalpha(*c))
+			*c += tolower(*c) < 'n' ? 13 : -13;
+	return str;
+}
+
+static char *get_value(char *buf, const char *key)
+{
+	const char *orig_buf = buf;
+	if (!buf ||
+	    !skip_prefix((const char *)buf, key, (const char **)&buf) ||
+	    !skip_prefix((const char *)buf, "=", (const char **)&buf) ||
+	    !*buf)
+		die("expected key '%s', got '%s'", key, str_or_null(orig_buf));
+	return buf;
+}
+
+/*
+ * Read a text packet, expecting that it is in the form "key=value" for
+ * the given key. An EOF does not trigger any error and is reported
+ * back to the caller with NULL. Die if the "key" part of "key=value" does
+ * not match the given key, or the value part is empty.
+ */
+static char *packet_key_val_read(const char *key)
+{
+	char *buf;
+	if (packet_read_line_gently(0, NULL, &buf) < 0)
+		return NULL;
+	return xstrdup(get_value(buf, key));
+}
+
+static inline void assert_remote_capability(struct strset *caps, const char *cap)
+{
+	if (!strset_contains(caps, cap))
+		die("required '%s' capability not available from remote", cap);
+}
+
+static void read_capabilities(struct strset *remote_caps)
+{
+	for (;;) {
+		char *buf = packet_read_line(0, NULL);
+		if (!buf)
+			break;
+		strset_add(remote_caps, get_value(buf, "capability"));
+	}
+
+	assert_remote_capability(remote_caps, "clean");
+	assert_remote_capability(remote_caps, "smudge");
+	assert_remote_capability(remote_caps, "delay");
+}
+
+static void check_and_write_capabilities(struct strset *remote_caps,
+					 const char **caps, int nr_caps)
+{
+	int i;
+	for (i = 0; i < nr_caps; i++) {
+		if (!strset_contains(remote_caps, caps[i]))
+			die("our capability '%s' is not available from remote",
+			    caps[i]);
+		packet_write_fmt(1, "capability=%s\n", caps[i]);
+	}
+	packet_flush(1);
+}
+
+struct delay_entry {
+	int requested, count;
+	char *output;
+};
+
+static void free_delay_entries(void)
+{
+	struct hashmap_iter iter;
+	struct strmap_entry *ent;
+
+	strmap_for_each_entry(&delay, &iter, ent) {
+		struct delay_entry *delay_entry = ent->value;
+		free(delay_entry->output);
+		free(delay_entry);
+	}
+	strmap_clear(&delay, 0);
+}
+
+static void add_delay_entry(char *pathname, int count, int requested)
+{
+	struct delay_entry *entry = xcalloc(1, sizeof(*entry));
+	entry->count = count;
+	entry->requested = requested;
+	if (strmap_put(&delay, pathname, entry))
+		BUG("adding the same path twice to delay hash?");
+}
+
+static void reply_list_available_blobs_cmd(void)
+{
+	struct hashmap_iter iter;
+	struct strmap_entry *ent;
+	struct string_list_item *str_item;
+	struct string_list paths = STRING_LIST_INIT_NODUP;
+
+	/* flush */
+	if (packet_read_line(0, NULL))
+		die("bad list_available_blobs end");
+
+	strmap_for_each_entry(&delay, &iter, ent) {
+		struct delay_entry *delay_entry = ent->value;
+		if (!delay_entry->requested)
+			continue;
+		delay_entry->count--;
+		if (!strcmp(ent->key, "invalid-delay.a")) {
+			/* Send Git a pathname that was not delayed earlier */
+			packet_write_fmt(1, "pathname=unfiltered");
+		}
+		if (!strcmp(ent->key, "missing-delay.a")) {
+			/* Do not signal Git that this file is available */
+		} else if (!delay_entry->count) {
+			string_list_append(&paths, ent->key);
+			packet_write_fmt(1, "pathname=%s", ent->key);
+		}
+	}
+
+	/* Print paths in sorted order. */
+	string_list_sort(&paths);
+	for_each_string_list_item(str_item, &paths)
+		fprintf(logfile, " %s", str_item->string);
+	string_list_clear(&paths, 0);
+
+	packet_flush(1);
+
+	fprintf(logfile, " [OK]\n");
+	packet_write_fmt(1, "status=success");
+	packet_flush(1);
+}
+
+static void command_loop(void)
+{
+	for (;;) {
+		char *buf, *output;
+		char *pathname;
+		struct delay_entry *entry;
+		struct strbuf input = STRBUF_INIT;
+		char *command = packet_key_val_read("command");
+
+		if (!command) {
+			fprintf(logfile, "STOP\n");
+			break;
+		}
+		fprintf(logfile, "IN: %s", command);
+
+		if (!strcmp(command, "list_available_blobs")) {
+			reply_list_available_blobs_cmd();
+			free(command);
+			continue;
+		}
+
+		pathname = packet_key_val_read("pathname");
+		if (!pathname)
+			die("unexpected EOF while expecting pathname");
+		fprintf(logfile, " %s", pathname);
+
+		/* Read until flush */
+		while ((buf = packet_read_line(0, NULL))) {
+			if (!strcmp(buf, "can-delay=1")) {
+				entry = strmap_get(&delay, pathname);
+				if (entry && !entry->requested)
+					entry->requested = 1;
+				else if (!entry && always_delay)
+					add_delay_entry(pathname, 1, 1);
+			} else if (starts_with(buf, "ref=") ||
+				   starts_with(buf, "treeish=") ||
+				   starts_with(buf, "blob=")) {
+				fprintf(logfile, " %s", buf);
+			} else {
+				/*
+				 * In general, filters need to be graceful about
+				 * new metadata, since it's documented that we
+				 * can pass any key-value pairs, but for tests,
+				 * let's be a little stricter.
+				 */
+				die("Unknown message '%s'", buf);
+			}
+		}
+
+		read_packetized_to_strbuf(0, &input, 0);
+		fprintf(logfile, " %"PRIuMAX" [OK] -- ", (uintmax_t)input.len);
+
+		entry = strmap_get(&delay, pathname);
+		if (entry && entry->output) {
+			output = entry->output;
+		} else if (!strcmp(pathname, "error.r") || !strcmp(pathname, "abort.r")) {
+			output = "";
+		} else if (!strcmp(command, "clean") && has_clean_cap) {
+			output = rot13(input.buf);
+		} else if (!strcmp(command, "smudge") && has_smudge_cap) {
+			output = rot13(input.buf);
+		} else {
+			die("bad command '%s'", command);
+		}
+
+		if (!strcmp(pathname, "error.r")) {
+			fprintf(logfile, "[ERROR]\n");
+			packet_write_fmt(1, "status=error");
+			packet_flush(1);
+		} else if (!strcmp(pathname, "abort.r")) {
+			fprintf(logfile, "[ABORT]\n");
+			packet_write_fmt(1, "status=abort");
+			packet_flush(1);
+		} else if (!strcmp(command, "smudge") &&
+			   (entry = strmap_get(&delay, pathname)) &&
+			   entry->requested == 1) {
+			fprintf(logfile, "[DELAYED]\n");
+			packet_write_fmt(1, "status=delayed");
+			packet_flush(1);
+			entry->requested = 2;
+			if (entry->output != output) {
+				free(entry->output);
+				entry->output = xstrdup(output);
+			}
+		} else {
+			int i, nr_packets = 0;
+			size_t output_len;
+			const char *p;
+			packet_write_fmt(1, "status=success");
+			packet_flush(1);
+
+			if (skip_prefix(pathname, command, &p) &&
+			    !strcmp(p, "-write-fail.r")) {
+				fprintf(logfile, "[WRITE FAIL]\n");
+				die("%s write error", command);
+			}
+
+			output_len = strlen(output);
+			fprintf(logfile, "OUT: %"PRIuMAX" ", (uintmax_t)output_len);
+
+			if (write_packetized_from_buf_no_flush_count(output,
+				output_len, 1, &nr_packets))
+				die("failed to write buffer to stdout");
+			packet_flush(1);
+
+			for (i = 0; i < nr_packets; i++)
+				fprintf(logfile, ".");
+			fprintf(logfile, " [OK]\n");
+
+			packet_flush(1);
+		}
+		free(pathname);
+		strbuf_release(&input);
+		free(command);
+	}
+}
+
+static void packet_initialize(void)
+{
+	char *pkt_buf = packet_read_line(0, NULL);
+
+	if (!pkt_buf || strcmp(pkt_buf, "git-filter-client"))
+		die("bad initialize: '%s'", str_or_null(pkt_buf));
+
+	pkt_buf = packet_read_line(0, NULL);
+	if (!pkt_buf || strcmp(pkt_buf, "version=2"))
+		die("bad version: '%s'", str_or_null(pkt_buf));
+
+	pkt_buf = packet_read_line(0, NULL);
+	if (pkt_buf)
+		die("bad version end: '%s'", pkt_buf);
+
+	packet_write_fmt(1, "git-filter-server");
+	packet_write_fmt(1, "version=2");
+	packet_flush(1);
+}
+
+static const char *rot13_usage[] = {
+	"test-tool rot13-filter [--always-delay] --log=<path> <capabilities>",
+	NULL
+};
+
+int cmd__rot13_filter(int argc, const char **argv)
+{
+	int i, nr_caps;
+	struct strset remote_caps = STRSET_INIT;
+	const char *log_path = NULL;
+
+	struct option options[] = {
+		OPT_BOOL(0, "always-delay", &always_delay,
+			 "delay all paths with the can-delay flag"),
+		OPT_STRING(0, "log", &log_path, "path",
+			   "path to the debug log file"),
+		OPT_END()
+	};
+	nr_caps = parse_options(argc, argv, NULL, options, rot13_usage,
+				PARSE_OPT_STOP_AT_NON_OPTION);
+
+	if (!log_path || !nr_caps)
+		usage_with_options(rot13_usage, options);
+
+	logfile = fopen(log_path, "a");
+	if (!logfile)
+		die_errno("failed to open log file");
+
+	for (i = 0; i < nr_caps; i++) {
+		if (!strcmp(argv[i], "smudge"))
+			has_smudge_cap = 1;
+		if (!strcmp(argv[i], "clean"))
+			has_clean_cap = 1;
+	}
+
+	add_delay_entry("test-delay10.a", 1, 0);
+	add_delay_entry("test-delay11.a", 1, 0);
+	add_delay_entry("test-delay20.a", 2, 0);
+	add_delay_entry("test-delay10.b", 1, 0);
+	add_delay_entry("missing-delay.a", 1, 0);
+	add_delay_entry("invalid-delay.a", 1, 0);
+
+	fprintf(logfile, "START\n");
+	packet_initialize();
+
+	read_capabilities(&remote_caps);
+	check_and_write_capabilities(&remote_caps, argv, nr_caps);
+	fprintf(logfile, "init handshake complete\n");
+	strset_clear(&remote_caps);
+
+	command_loop();
+
+	if (fclose(logfile))
+		die_errno("error closing logfile");
+	free_delay_entries();
+	return 0;
+}
diff --git a/t/helper/test-scrap-cache-tree.c b/t/helper/test-scrap-cache-tree.c
index 393f160..026c802 100644
--- a/t/helper/test-scrap-cache-tree.c
+++ b/t/helper/test-scrap-cache-tree.c
@@ -12,6 +12,7 @@
 	hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
 	if (read_cache() < 0)
 		die("unable to read index file");
+	cache_tree_free(&active_cache_tree);
 	active_cache_tree = NULL;
 	if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
 		die("unable to write index file");
diff --git a/t/helper/test-serve-v2.c b/t/helper/test-serve-v2.c
index 28e905a..824e5c0 100644
--- a/t/helper/test-serve-v2.c
+++ b/t/helper/test-serve-v2.c
@@ -24,7 +24,7 @@
 	/* ignore all unknown cmdline switches for now */
 	argc = parse_options(argc, argv, prefix, options, serve_usage,
 			     PARSE_OPT_KEEP_DASHDASH |
-			     PARSE_OPT_KEEP_UNKNOWN);
+			     PARSE_OPT_KEEP_UNKNOWN_OPT);
 
 	if (advertise_capabilities)
 		protocol_v2_advertise_capabilities();
diff --git a/t/helper/test-submodule-config.c b/t/helper/test-submodule-config.c
index e269274..22a41c4 100644
--- a/t/helper/test-submodule-config.c
+++ b/t/helper/test-submodule-config.c
@@ -15,14 +15,11 @@
 {
 	const char **arg = argv;
 	int my_argc = argc;
-	int output_url = 0;
 	int lookup_name = 0;
 
 	arg++;
 	my_argc--;
 	while (arg[0] && starts_with(arg[0], "--")) {
-		if (!strcmp(arg[0], "--url"))
-			output_url = 1;
 		if (!strcmp(arg[0], "--name"))
 			lookup_name = 1;
 		arg++;
@@ -57,12 +54,8 @@
 		if (!submodule)
 			die_usage(argc, argv, "Submodule not found.");
 
-		if (output_url)
-			printf("Submodule url: '%s' for path '%s'\n",
-					submodule->url, submodule->path);
-		else
-			printf("Submodule name: '%s' for path '%s'\n",
-					submodule->name, submodule->path);
+		printf("Submodule name: '%s' for path '%s'\n", submodule->name,
+		       submodule->path);
 
 		arg += 2;
 	}
diff --git a/t/helper/test-submodule.c b/t/helper/test-submodule.c
new file mode 100644
index 0000000..e0e0c53
--- /dev/null
+++ b/t/helper/test-submodule.c
@@ -0,0 +1,146 @@
+#include "test-tool.h"
+#include "test-tool-utils.h"
+#include "cache.h"
+#include "parse-options.h"
+#include "remote.h"
+#include "submodule-config.h"
+#include "submodule.h"
+
+#define TEST_TOOL_CHECK_NAME_USAGE \
+	"test-tool submodule check-name <name>"
+static const char *submodule_check_name_usage[] = {
+	TEST_TOOL_CHECK_NAME_USAGE,
+	NULL
+};
+
+#define TEST_TOOL_IS_ACTIVE_USAGE \
+	"test-tool submodule is-active <name>"
+static const char *submodule_is_active_usage[] = {
+	TEST_TOOL_IS_ACTIVE_USAGE,
+	NULL
+};
+
+#define TEST_TOOL_RESOLVE_RELATIVE_URL_USAGE \
+	"test-tool submodule resolve-relative-url <up_path> <remoteurl> <url>"
+static const char *submodule_resolve_relative_url_usage[] = {
+	TEST_TOOL_RESOLVE_RELATIVE_URL_USAGE,
+	NULL,
+};
+
+static const char *submodule_usage[] = {
+	TEST_TOOL_CHECK_NAME_USAGE,
+	TEST_TOOL_IS_ACTIVE_USAGE,
+	TEST_TOOL_RESOLVE_RELATIVE_URL_USAGE,
+	NULL
+};
+
+/*
+ * Exit non-zero if any of the submodule names given on the command line is
+ * invalid. If no names are given, filter stdin to print only valid names
+ * (which is primarily intended for testing).
+ */
+static int check_name(int argc, const char **argv)
+{
+	if (argc > 1) {
+		while (*++argv) {
+			if (check_submodule_name(*argv) < 0)
+				return 1;
+		}
+	} else {
+		struct strbuf buf = STRBUF_INIT;
+		while (strbuf_getline(&buf, stdin) != EOF) {
+			if (!check_submodule_name(buf.buf))
+				printf("%s\n", buf.buf);
+		}
+		strbuf_release(&buf);
+	}
+	return 0;
+}
+
+static int cmd__submodule_check_name(int argc, const char **argv)
+{
+	struct option options[] = {
+		OPT_END()
+	};
+	argc = parse_options(argc, argv, "test-tools", options,
+			     submodule_check_name_usage, 0);
+	if (argc)
+		usage_with_options(submodule_check_name_usage, options);
+
+	return check_name(argc, argv);
+}
+
+static int cmd__submodule_is_active(int argc, const char **argv)
+{
+	struct option options[] = {
+		OPT_END()
+	};
+	argc = parse_options(argc, argv, "test-tools", options,
+			     submodule_is_active_usage, 0);
+	if (argc != 1)
+		usage_with_options(submodule_is_active_usage, options);
+
+	setup_git_directory();
+
+	return !is_submodule_active(the_repository, argv[0]);
+}
+
+static int resolve_relative_url(int argc, const char **argv)
+{
+	char *remoteurl, *res;
+	const char *up_path, *url;
+
+	up_path = argv[0];
+	remoteurl = xstrdup(argv[1]);
+	url = argv[2];
+
+	if (!strcmp(up_path, "(null)"))
+		up_path = NULL;
+
+	res = relative_url(remoteurl, url, up_path);
+	puts(res);
+	free(res);
+	free(remoteurl);
+	return 0;
+}
+
+static int cmd__submodule_resolve_relative_url(int argc, const char **argv)
+{
+	struct option options[] = {
+		OPT_END()
+	};
+	argc = parse_options(argc, argv, "test-tools", options,
+			     submodule_resolve_relative_url_usage, 0);
+	if (argc != 3)
+		usage_with_options(submodule_resolve_relative_url_usage, options);
+
+	return resolve_relative_url(argc, argv);
+}
+
+static struct test_cmd cmds[] = {
+	{ "check-name", cmd__submodule_check_name },
+	{ "is-active", cmd__submodule_is_active },
+	{ "resolve-relative-url", cmd__submodule_resolve_relative_url},
+};
+
+int cmd__submodule(int argc, const char **argv)
+{
+	struct option options[] = {
+		OPT_END()
+	};
+	size_t i;
+
+	argc = parse_options(argc, argv, "test-tools", options, submodule_usage,
+			     PARSE_OPT_STOP_AT_NON_OPTION);
+	if (argc < 1)
+		usage_with_options(submodule_usage, options);
+
+	for (i = 0; i < ARRAY_SIZE(cmds); i++)
+		if (!strcmp(cmds[i].name, argv[0]))
+			return cmds[i].fn(argc, argv);
+
+	usage_msg_optf("unknown subcommand '%s'", submodule_usage, options,
+		       argv[0]);
+
+	return 0;
+}
diff --git a/t/helper/test-tool-utils.h b/t/helper/test-tool-utils.h
new file mode 100644
index 0000000..6a0e5e0
--- /dev/null
+++ b/t/helper/test-tool-utils.h
@@ -0,0 +1,9 @@
+#ifndef TEST_TOOL_UTILS_H
+#define TEST_TOOL_UTILS_H
+
+struct test_cmd {
+	const char *name;
+	int (*fn)(int argc, const char **argv);
+};
+
+#endif
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 318fdba..d1d013b 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -1,5 +1,6 @@
 #include "git-compat-util.h"
 #include "test-tool.h"
+#include "test-tool-utils.h"
 #include "trace2.h"
 #include "parse-options.h"
 
@@ -8,11 +9,6 @@
 	NULL
 };
 
-struct test_cmd {
-	const char *name;
-	int (*fn)(int argc, const char **argv);
-};
-
 static struct test_cmd cmds[] = {
 	{ "advise", cmd__advise_if_enabled },
 	{ "bitmap", cmd__bitmap },
@@ -51,7 +47,9 @@
 	{ "online-cpus", cmd__online_cpus },
 	{ "pack-mtimes", cmd__pack_mtimes },
 	{ "parse-options", cmd__parse_options },
+	{ "parse-options-flags", cmd__parse_options_flags },
 	{ "parse-pathspec-file", cmd__parse_pathspec_file },
+	{ "parse-subcommand", cmd__parse_subcommand },
 	{ "partial-clone", cmd__partial_clone },
 	{ "path-utils", cmd__path_utils },
 	{ "pcre2-config", cmd__pcre2_config },
@@ -65,6 +63,7 @@
 	{ "read-midx", cmd__read_midx },
 	{ "ref-store", cmd__ref_store },
 	{ "reftable", cmd__reftable },
+	{ "rot13-filter", cmd__rot13_filter },
 	{ "dump-reftable", cmd__dump_reftable },
 	{ "regex", cmd__regex },
 	{ "repository", cmd__repository },
@@ -78,6 +77,7 @@
 	{ "simple-ipc", cmd__simple_ipc },
 	{ "strcmp-offset", cmd__strcmp_offset },
 	{ "string-list", cmd__string_list },
+	{ "submodule", cmd__submodule },
 	{ "submodule-config", cmd__submodule_config },
 	{ "submodule-nested-repo-config", cmd__submodule_nested_repo_config },
 	{ "subprocess", cmd__subprocess },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index bb79927..6b46b64 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -41,7 +41,9 @@
 int cmd__online_cpus(int argc, const char **argv);
 int cmd__pack_mtimes(int argc, const char **argv);
 int cmd__parse_options(int argc, const char **argv);
+int cmd__parse_options_flags(int argc, const char **argv);
 int cmd__parse_pathspec_file(int argc, const char** argv);
+int cmd__parse_subcommand(int argc, const char **argv);
 int cmd__partial_clone(int argc, const char **argv);
 int cmd__path_utils(int argc, const char **argv);
 int cmd__pcre2_config(int argc, const char **argv);
@@ -54,6 +56,7 @@
 int cmd__read_graph(int argc, const char **argv);
 int cmd__read_midx(int argc, const char **argv);
 int cmd__ref_store(int argc, const char **argv);
+int cmd__rot13_filter(int argc, const char **argv);
 int cmd__reftable(int argc, const char **argv);
 int cmd__regex(int argc, const char **argv);
 int cmd__repository(int argc, const char **argv);
@@ -68,6 +71,7 @@
 int cmd__simple_ipc(int argc, const char **argv);
 int cmd__strcmp_offset(int argc, const char **argv);
 int cmd__string_list(int argc, const char **argv);
+int cmd__submodule(int argc, const char **argv);
 int cmd__submodule_config(int argc, const char **argv);
 int cmd__submodule_nested_repo_config(int argc, const char **argv);
 int cmd__subprocess(int argc, const char **argv);
diff --git a/t/helper/test-urlmatch-normalization.c b/t/helper/test-urlmatch-normalization.c
index 8f4d67e..86edd45 100644
--- a/t/helper/test-urlmatch-normalization.c
+++ b/t/helper/test-urlmatch-normalization.c
@@ -5,8 +5,9 @@
 int cmd__urlmatch_normalization(int argc, const char **argv)
 {
 	const char usage[] = "test-tool urlmatch-normalization [-p | -l] <url1> | <url1> <url2>";
-	char *url1, *url2;
+	char *url1 = NULL, *url2 = NULL;
 	int opt_p = 0, opt_l = 0;
+	int ret = 0;
 
 	/*
 	 * For one url, succeed if url_normalize succeeds on it, fail otherwise.
@@ -39,7 +40,7 @@
 			printf("%s\n", url1);
 		if (opt_l)
 			printf("%u\n", (unsigned)info.url_len);
-		return 0;
+		goto cleanup;
 	}
 
 	if (opt_p || opt_l)
@@ -47,5 +48,9 @@
 
 	url1 = url_normalize(argv[1], NULL);
 	url2 = url_normalize(argv[2], NULL);
-	return (url1 && url2 && !strcmp(url1, url2)) ? 0 : 1;
+	ret = (url1 && url2 && !strcmp(url1, url2)) ? 0 : 1;
+cleanup:
+	free(url1);
+	free(url2);
+	return ret;
 }
diff --git a/t/helper/test-userdiff.c b/t/helper/test-userdiff.c
index f013f8a..a2b56b9 100644
--- a/t/helper/test-userdiff.c
+++ b/t/helper/test-userdiff.c
@@ -12,7 +12,7 @@
 	return 0;
 }
 
-static int cmd__userdiff_config(const char *var, const char *value, void *cb)
+static int cmd__userdiff_config(const char *var, const char *value, void *cb UNUSED)
 {
 	if (userdiff_config(var, value) < 0)
 		return -1;
diff --git a/t/lib-bitmap.sh b/t/lib-bitmap.sh
index a95537e..f595937 100644
--- a/t/lib-bitmap.sh
+++ b/t/lib-bitmap.sh
@@ -440,7 +440,7 @@
 		test_commit packed &&
 		git repack &&
 		test_commit loose &&
-		git multi-pack-index write --bitmap 2>err &&
+		git multi-pack-index write --bitmap &&
 		test_path_is_file $midx &&
 		test_path_is_file $midx-$(midx_checksum $objdir).bitmap
 	'
diff --git a/t/lib-perl.sh b/t/lib-perl.sh
new file mode 100644
index 0000000..d0bf509
--- /dev/null
+++ b/t/lib-perl.sh
@@ -0,0 +1,19 @@
+# Copyright (c) 2022 Ævar Arnfjörð Bjarmason
+
+test_lazy_prereq PERL_TEST_MORE '
+	perl -MTest::More -e 0
+'
+
+skip_all_if_no_Test_More () {
+	if ! test_have_prereq PERL
+	then
+		skip_all='skipping perl interface tests, perl not available'
+		test_done
+	fi
+
+	if ! test_have_prereq PERL_TEST_MORE
+	then
+		skip_all="Perl Test::More unavailable, skipping test"
+		test_done
+	fi
+}
diff --git a/t/lib-rebase.sh b/t/lib-rebase.sh
index ec6b9b1..b575413 100644
--- a/t/lib-rebase.sh
+++ b/t/lib-rebase.sh
@@ -207,3 +207,18 @@
 		>reword-log &&
 	test_cmp reword-expected reword-log
 }
+
+# usage: set_replace_editor <file>
+#
+# Replace the todo file with the exact contents of the given file.
+set_replace_editor () {
+	cat >script <<-\EOF &&
+	cat FILENAME >"$1"
+
+	echo 'rebase -i script after editing:'
+	cat "$1"
+	EOF
+
+	sed -e "s/FILENAME/$1/g" <script | write_script fake-editor.sh &&
+	test_set_editor "$(pwd)/fake-editor.sh"
+}
diff --git a/t/lib-submodule-update.sh b/t/lib-submodule-update.sh
index f7c7df0..03e0abb 100644
--- a/t/lib-submodule-update.sh
+++ b/t/lib-submodule-update.sh
@@ -207,7 +207,7 @@
 # should be updated to an existing commit.
 reset_work_tree_to () {
 	rm -rf submodule_update &&
-	git clone submodule_update_repo submodule_update &&
+	git clone --template= submodule_update_repo submodule_update &&
 	(
 		cd submodule_update &&
 		rm -rf sub1 &&
@@ -902,13 +902,14 @@
 	'
 	# ... but an ignored file is fine.
 	test_expect_$RESULTOI "$command: added submodule removes an untracked ignored file" '
-		test_when_finished "rm submodule_update/.git/info/exclude" &&
+		test_when_finished "rm -rf submodule_update/.git/info" &&
 		prolog &&
 		reset_work_tree_to_interested no_submodule &&
 		(
 			cd submodule_update &&
 			git branch -t add_sub1 origin/add_sub1 &&
 			: >sub1 &&
+			mkdir .git/info &&
 			echo sub1 >.git/info/exclude &&
 			$command add_sub1 &&
 			test_superproject_content origin/add_sub1 &&
@@ -951,7 +952,9 @@
 		reset_work_tree_to_interested add_sub1 &&
 		(
 			cd submodule_update &&
+			rm -rf .git/modules/sub1/info &&
 			git branch -t replace_sub1_with_file origin/replace_sub1_with_file &&
+			mkdir .git/modules/sub1/info &&
 			echo ignored >.git/modules/sub1/info/exclude &&
 			: >sub1/ignored &&
 			$command replace_sub1_with_file &&
diff --git a/t/perf/lib-bitmap.sh b/t/perf/lib-bitmap.sh
index 63d3bc7..55a8feb 100644
--- a/t/perf/lib-bitmap.sh
+++ b/t/perf/lib-bitmap.sh
@@ -67,3 +67,34 @@
 			--filter=tree:0 >/dev/null
 	'
 }
+
+test_pack_bitmap () {
+	test_perf "repack to disk" '
+		git repack -ad
+	'
+
+	test_full_bitmap
+
+	test_expect_success "create partial bitmap state" '
+		# pick a commit to represent the repo tip in the past
+		cutoff=$(git rev-list HEAD~100 -1) &&
+		orig_tip=$(git rev-parse HEAD) &&
+
+		# now kill off all of the refs and pretend we had
+		# just the one tip
+		rm -rf .git/logs .git/refs/* .git/packed-refs &&
+		git update-ref HEAD $cutoff &&
+
+		# and then repack, which will leave us with a nice
+		# big bitmap pack of the "old" history, and all of
+		# the new history will be loose, as if it had been pushed
+		# up incrementally and exploded via unpack-objects
+		git repack -Ad &&
+
+		# and now restore our original tip, as if the pushes
+		# had happened
+		git update-ref HEAD $orig_tip
+	'
+
+	test_partial_bitmap
+}
diff --git a/t/perf/p0004-lazy-init-name-hash.sh b/t/perf/p0004-lazy-init-name-hash.sh
index 1afc08f..85be14e 100755
--- a/t/perf/p0004-lazy-init-name-hash.sh
+++ b/t/perf/p0004-lazy-init-name-hash.sh
@@ -49,7 +49,7 @@
 	test-tool lazy-init-name-hash --single --count=$count
 "
 
-test_perf REPO_BIG_ENOUGH_FOR_MULTI "multi-threaded, $desc" "
+test_perf "multi-threaded, $desc" --prereq REPO_BIG_ENOUGH_FOR_MULTI "
 	test-tool lazy-init-name-hash --multi --count=$count
 "
 
diff --git a/t/perf/p0006-read-tree-checkout.sh b/t/perf/p0006-read-tree-checkout.sh
index 900b385..c481c01 100755
--- a/t/perf/p0006-read-tree-checkout.sh
+++ b/t/perf/p0006-read-tree-checkout.sh
@@ -46,7 +46,7 @@
 '
 
 test_perf "read-tree br_base br_ballast ($nr_files)" '
-	git read-tree -m br_base br_ballast -n
+	git read-tree -n -m br_base br_ballast
 '
 
 test_perf "switch between br_base br_ballast ($nr_files)" '
diff --git a/t/perf/p0071-sort.sh b/t/perf/p0071-sort.sh
index ed366e2..ae4ddac 100755
--- a/t/perf/p0071-sort.sh
+++ b/t/perf/p0071-sort.sh
@@ -40,11 +40,11 @@
 
 for file in unsorted sorted reversed
 do
-	test_perf "llist_mergesort() $file" "
+	test_perf "DEFINE_LIST_SORT $file" "
 		test-tool mergesort sort <$file >actual
 	"
 
-	test_expect_success "llist_mergesort() $file sorts like sort(1)" "
+	test_expect_success "DEFINE_LIST_SORT $file sorts like sort(1)" "
 		test_cmp_bin sorted actual
 	"
 done
diff --git a/t/perf/p2000-sparse-operations.sh b/t/perf/p2000-sparse-operations.sh
index c181110..fce8151 100755
--- a/t/perf/p2000-sparse-operations.sh
+++ b/t/perf/p2000-sparse-operations.sh
@@ -123,5 +123,6 @@
 test_perf_on_all git read-tree -mu HEAD
 test_perf_on_all git checkout-index -f --all
 test_perf_on_all git update-index --add --remove $SPARSE_CONE/a
+test_perf_on_all "git rm -f $SPARSE_CONE/a && git checkout HEAD -- $SPARSE_CONE/a"
 
 test_done
diff --git a/t/perf/p5310-pack-bitmaps.sh b/t/perf/p5310-pack-bitmaps.sh
index 7ad4f23..b1399f1 100755
--- a/t/perf/p5310-pack-bitmaps.sh
+++ b/t/perf/p5310-pack-bitmaps.sh
@@ -4,51 +4,37 @@
 . ./perf-lib.sh
 . "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
 
-test_perf_large_repo
+test_lookup_pack_bitmap () {
+	test_expect_success 'start the test from scratch' '
+		rm -rf * .git
+	'
 
-# note that we do everything through config,
-# since we want to be able to compare bitmap-aware
-# git versus non-bitmap git
-#
-# We intentionally use the deprecated pack.writebitmaps
-# config so that we can test against older versions of git.
-test_expect_success 'setup bitmap config' '
-	git config pack.writebitmaps true
-'
+	test_perf_large_repo
 
-# we need to create the tag up front such that it is covered by the repack and
-# thus by generated bitmaps.
-test_expect_success 'create tags' '
-	git tag --message="tag pointing to HEAD" perf-tag HEAD
-'
+	# note that we do everything through config,
+	# since we want to be able to compare bitmap-aware
+	# git versus non-bitmap git
+	#
+	# We intentionally use the deprecated pack.writebitmaps
+	# config so that we can test against older versions of git.
+	test_expect_success 'setup bitmap config' '
+		git config pack.writebitmaps true
+	'
 
-test_perf 'repack to disk' '
-	git repack -ad
-'
+	# we need to create the tag up front such that it is covered by the repack and
+	# thus by generated bitmaps.
+	test_expect_success 'create tags' '
+		git tag --message="tag pointing to HEAD" perf-tag HEAD
+	'
 
-test_full_bitmap
+	test_perf "enable lookup table: $1" '
+		git config pack.writeBitmapLookupTable '"$1"'
+	'
 
-test_expect_success 'create partial bitmap state' '
-	# pick a commit to represent the repo tip in the past
-	cutoff=$(git rev-list HEAD~100 -1) &&
-	orig_tip=$(git rev-parse HEAD) &&
+	test_pack_bitmap
+}
 
-	# now kill off all of the refs and pretend we had
-	# just the one tip
-	rm -rf .git/logs .git/refs/* .git/packed-refs &&
-	git update-ref HEAD $cutoff &&
-
-	# and then repack, which will leave us with a nice
-	# big bitmap pack of the "old" history, and all of
-	# the new history will be loose, as if it had been pushed
-	# up incrementally and exploded via unpack-objects
-	git repack -Ad &&
-
-	# and now restore our original tip, as if the pushes
-	# had happened
-	git update-ref HEAD $orig_tip
-'
-
-test_partial_bitmap
+test_lookup_pack_bitmap false
+test_lookup_pack_bitmap true
 
 test_done
diff --git a/t/perf/p5311-pack-bitmaps-fetch.sh b/t/perf/p5311-pack-bitmaps-fetch.sh
index 47c3fd7..426fab8 100755
--- a/t/perf/p5311-pack-bitmaps-fetch.sh
+++ b/t/perf/p5311-pack-bitmaps-fetch.sh
@@ -3,42 +3,52 @@
 test_description='performance of fetches from bitmapped packs'
 . ./perf-lib.sh
 
-test_perf_default_repo
-
-test_expect_success 'create bitmapped server repo' '
-	git config pack.writebitmaps true &&
-	git repack -ad
-'
-
-# simulate a fetch from a repository that last fetched N days ago, for
-# various values of N. We do so by following the first-parent chain,
-# and assume the first entry in the chain that is N days older than the current
-# HEAD is where the HEAD would have been then.
-for days in 1 2 4 8 16 32 64 128; do
-	title=$(printf '%10s' "($days days)")
-	test_expect_success "setup revs from $days days ago" '
-		now=$(git log -1 --format=%ct HEAD) &&
-		then=$(($now - ($days * 86400))) &&
-		tip=$(git rev-list -1 --first-parent --until=$then HEAD) &&
-		{
-			echo HEAD &&
-			echo ^$tip
-		} >revs
+test_fetch_bitmaps () {
+	test_expect_success 'setup test directory' '
+		rm -fr * .git
 	'
 
-	test_perf "server $title" '
-		git pack-objects --stdout --revs \
-				 --thin --delta-base-offset \
-				 <revs >tmp.pack
+	test_perf_default_repo
+
+	test_expect_success 'create bitmapped server repo' '
+		git config pack.writebitmaps true &&
+		git config pack.writeBitmapLookupTable '"$1"' &&
+		git repack -ad
 	'
 
-	test_size "size   $title" '
-		wc -c <tmp.pack
-	'
+	# simulate a fetch from a repository that last fetched N days ago, for
+	# various values of N. We do so by following the first-parent chain,
+	# and assume the first entry in the chain that is N days older than the current
+	# HEAD is where the HEAD would have been then.
+	for days in 1 2 4 8 16 32 64 128; do
+		title=$(printf '%10s' "($days days)")
+		test_expect_success "setup revs from $days days ago" '
+			now=$(git log -1 --format=%ct HEAD) &&
+			then=$(($now - ($days * 86400))) &&
+			tip=$(git rev-list -1 --first-parent --until=$then HEAD) &&
+			{
+				echo HEAD &&
+				echo ^$tip
+			} >revs
+		'
 
-	test_perf "client $title" '
-		git index-pack --stdin --fix-thin <tmp.pack
-	'
-done
+		test_perf "server $title (lookup=$1)" '
+			git pack-objects --stdout --revs \
+					--thin --delta-base-offset \
+					<revs >tmp.pack
+		'
+
+		test_size "size   $title" '
+			wc -c <tmp.pack
+		'
+
+		test_perf "client $title (lookup=$1)" '
+			git index-pack --stdin --fix-thin <tmp.pack
+		'
+	done
+}
+
+test_fetch_bitmaps true
+test_fetch_bitmaps false
 
 test_done
diff --git a/t/perf/p5312-pack-bitmaps-revs.sh b/t/perf/p5312-pack-bitmaps-revs.sh
new file mode 100755
index 0000000..0684b69
--- /dev/null
+++ b/t/perf/p5312-pack-bitmaps-revs.sh
@@ -0,0 +1,35 @@
+#!/bin/sh
+
+test_description='Tests pack performance using bitmaps (rev index enabled)'
+. ./perf-lib.sh
+. "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
+
+test_lookup_pack_bitmap () {
+	test_expect_success 'start the test from scratch' '
+		rm -rf * .git
+	'
+
+	test_perf_large_repo
+
+	test_expect_success 'setup bitmap config' '
+		git config pack.writebitmaps true &&
+		git config pack.writeReverseIndex true
+	'
+
+	# we need to create the tag up front such that it is covered by the repack and
+	# thus by generated bitmaps.
+	test_expect_success 'create tags' '
+		git tag --message="tag pointing to HEAD" perf-tag HEAD
+	'
+
+	test_perf "enable lookup table: $1" '
+		git config pack.writeBitmapLookupTable '"$1"'
+	'
+
+	test_pack_bitmap
+}
+
+test_lookup_pack_bitmap false
+test_lookup_pack_bitmap true
+
+test_done
diff --git a/t/perf/p5326-multi-pack-bitmaps.sh b/t/perf/p5326-multi-pack-bitmaps.sh
index f2fa228..d082e6c 100755
--- a/t/perf/p5326-multi-pack-bitmaps.sh
+++ b/t/perf/p5326-multi-pack-bitmaps.sh
@@ -4,49 +4,64 @@
 . ./perf-lib.sh
 . "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
 
-test_perf_large_repo
+test_bitmap () {
+	local enabled="$1"
 
-# we need to create the tag up front such that it is covered by the repack and
-# thus by generated bitmaps.
-test_expect_success 'create tags' '
-	git tag --message="tag pointing to HEAD" perf-tag HEAD
-'
+	test_expect_success "remove existing repo (lookup=$enabled)" '
+		rm -fr * .git
+	'
 
-test_expect_success 'start with bitmapped pack' '
-	git repack -adb
-'
+	test_perf_large_repo
 
-test_perf 'setup multi-pack index' '
-	git multi-pack-index write --bitmap
-'
+	# we need to create the tag up front such that it is covered by the repack and
+	# thus by generated bitmaps.
+	test_expect_success 'create tags' '
+		git tag --message="tag pointing to HEAD" perf-tag HEAD
+	'
 
-test_expect_success 'drop pack bitmap' '
-	rm -f .git/objects/pack/pack-*.bitmap
-'
+	test_expect_success "use lookup table: $enabled" '
+		git config pack.writeBitmapLookupTable '"$enabled"'
+	'
 
-test_full_bitmap
+	test_expect_success "start with bitmapped pack (lookup=$enabled)" '
+		git repack -adb
+	'
 
-test_expect_success 'create partial bitmap state' '
-	# pick a commit to represent the repo tip in the past
-	cutoff=$(git rev-list HEAD~100 -1) &&
-	orig_tip=$(git rev-parse HEAD) &&
+	test_perf "setup multi-pack index (lookup=$enabled)" '
+		git multi-pack-index write --bitmap
+	'
 
-	# now pretend we have just one tip
-	rm -rf .git/logs .git/refs/* .git/packed-refs &&
-	git update-ref HEAD $cutoff &&
+	test_expect_success "drop pack bitmap (lookup=$enabled)" '
+		rm -f .git/objects/pack/pack-*.bitmap
+	'
 
-	# and then repack, which will leave us with a nice
-	# big bitmap pack of the "old" history, and all of
-	# the new history will be loose, as if it had been pushed
-	# up incrementally and exploded via unpack-objects
-	git repack -Ad &&
-	git multi-pack-index write --bitmap &&
+	test_full_bitmap
 
-	# and now restore our original tip, as if the pushes
-	# had happened
-	git update-ref HEAD $orig_tip
-'
+	test_expect_success "create partial bitmap state (lookup=$enabled)" '
+		# pick a commit to represent the repo tip in the past
+		cutoff=$(git rev-list HEAD~100 -1) &&
+		orig_tip=$(git rev-parse HEAD) &&
 
-test_partial_bitmap
+		# now pretend we have just one tip
+		rm -rf .git/logs .git/refs/* .git/packed-refs &&
+		git update-ref HEAD $cutoff &&
+
+		# and then repack, which will leave us with a nice
+		# big bitmap pack of the "old" history, and all of
+		# the new history will be loose, as if it had been pushed
+		# up incrementally and exploded via unpack-objects
+		git repack -Ad &&
+		git multi-pack-index write --bitmap &&
+
+		# and now restore our original tip, as if the pushes
+		# had happened
+		git update-ref HEAD $orig_tip
+	'
+
+	test_partial_bitmap
+}
+
+test_bitmap false
+test_bitmap true
 
 test_done
diff --git a/t/perf/p7527-builtin-fsmonitor.sh b/t/perf/p7527-builtin-fsmonitor.sh
index 9338b9e..c3f9a4c 100755
--- a/t/perf/p7527-builtin-fsmonitor.sh
+++ b/t/perf/p7527-builtin-fsmonitor.sh
@@ -249,7 +249,7 @@
 	do
 		for fsm_val in $fsm_values
 		do
-			cleanup $uc_val $fsm_val
+			cleanup $uc_val $fsm_val || return 1
 		done
 	done
 "
diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index 17a268c..502b4bc 100755
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh
@@ -578,6 +578,78 @@
 	EOF_ERR
 '
 
+test_expect_success 'subtest: --invert-exit-code without --immediate' '
+	run_sub_test_lib_test_err full-pass \
+		--invert-exit-code &&
+	check_sub_test_lib_test_err full-pass \
+		<<-\EOF_OUT 3<<-EOF_ERR
+	ok 1 - passing test #1
+	ok 2 - passing test #2
+	ok 3 - passing test #3
+	# passed all 3 test(s)
+	1..3
+	# faking up non-zero exit with --invert-exit-code
+	EOF_OUT
+	EOF_ERR
+'
+
+test_expect_success 'subtest: --invert-exit-code with --immediate: all passed' '
+	run_sub_test_lib_test_err full-pass \
+		--invert-exit-code --immediate &&
+	check_sub_test_lib_test_err full-pass \
+		<<-\EOF_OUT 3<<-EOF_ERR
+	ok 1 - passing test #1
+	ok 2 - passing test #2
+	ok 3 - passing test #3
+	# passed all 3 test(s)
+	1..3
+	# faking up non-zero exit with --invert-exit-code
+	EOF_OUT
+	EOF_ERR
+'
+
+test_expect_success 'subtest: --invert-exit-code without --immediate: partial pass' '
+	run_sub_test_lib_test partial-pass \
+		--invert-exit-code &&
+	check_sub_test_lib_test partial-pass <<-\EOF
+	ok 1 - passing test #1
+	not ok 2 - # TODO induced breakage (--invert-exit-code): failing test #2
+	#	false
+	ok 3 - passing test #3
+	# failed 1 among 3 test(s)
+	1..3
+	# faked up failures as TODO & now exiting with 0 due to --invert-exit-code
+	EOF
+'
+
+test_expect_success 'subtest: --invert-exit-code with --immediate: partial pass' '
+	run_sub_test_lib_test partial-pass \
+		--invert-exit-code --immediate &&
+	check_sub_test_lib_test partial-pass \
+		<<-\EOF_OUT 3<<-EOF_ERR
+	ok 1 - passing test #1
+	not ok 2 - # TODO induced breakage (--invert-exit-code): failing test #2
+	#	false
+	1..2
+	# faked up failures as TODO & now exiting with 0 due to --invert-exit-code
+	EOF_OUT
+	EOF_ERR
+'
+
+test_expect_success 'subtest: --invert-exit-code --immediate: got a failure' '
+	run_sub_test_lib_test partial-pass \
+		--invert-exit-code --immediate &&
+	check_sub_test_lib_test_err partial-pass \
+		<<-\EOF_OUT 3<<-EOF_ERR
+	ok 1 - passing test #1
+	not ok 2 - # TODO induced breakage (--invert-exit-code): failing test #2
+	#	false
+	1..2
+	# faked up failures as TODO & now exiting with 0 due to --invert-exit-code
+	EOF_OUT
+	EOF_ERR
+'
+
 test_expect_success 'subtest: tests respect prerequisites' '
 	write_and_run_sub_test_lib_test prereqs <<-\EOF &&
 
diff --git a/t/t0002-gitfile.sh b/t/t0002-gitfile.sh
index f6356db..26eaca0 100755
--- a/t/t0002-gitfile.sh
+++ b/t/t0002-gitfile.sh
@@ -65,7 +65,7 @@
 	test_path_is_file "$REAL/objects/$(objpath $SHA)"
 '
 
-test_expect_success !SANITIZE_LEAK 'check rev-list' '
+test_expect_success 'check rev-list' '
 	git update-ref "HEAD" "$SHA" &&
 	git rev-list HEAD >actual &&
 	echo $SHA >expected &&
diff --git a/t/t0003-attributes.sh b/t/t0003-attributes.sh
index 143f100..f7ee2f2 100755
--- a/t/t0003-attributes.sh
+++ b/t/t0003-attributes.sh
@@ -3,6 +3,7 @@
 test_description=gitattributes
 
 TEST_PASSES_SANITIZE_LEAK=true
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 attr_check_basic () {
@@ -284,7 +285,7 @@
 '
 
 test_expect_success 'setup bare' '
-	git clone --bare . bare.git
+	git clone --template= --bare . bare.git
 '
 
 test_expect_success 'bare repository: check that .gitattribute is ignored' '
@@ -315,6 +316,7 @@
 test_expect_success 'bare repository: test info/attributes' '
 	(
 		cd bare.git &&
+		mkdir info &&
 		(
 			echo "f	test=f" &&
 			echo "a/i test=a/i"
@@ -360,6 +362,7 @@
 
 test_expect_success SYMLINKS 'symlinks respected in info/attributes' '
 	test_when_finished "rm .git/info/attributes" &&
+	mkdir .git/info &&
 	ln -s ../../attr .git/info/attributes &&
 	attr_check file set
 '
diff --git a/t/t0004-unwritable.sh b/t/t0004-unwritable.sh
index 2e9d652..8114fac 100755
--- a/t/t0004-unwritable.sh
+++ b/t/t0004-unwritable.sh
@@ -31,7 +31,7 @@
 	test_cmp expect out.write-tree
 '
 
-test_expect_success POSIXPERM,SANITY,!SANITIZE_LEAK 'commit should notice unwritable repository' '
+test_expect_success POSIXPERM,SANITY 'commit should notice unwritable repository' '
 	test_when_finished "chmod 775 .git/objects .git/objects/??" &&
 	chmod a-w .git/objects .git/objects/?? &&
 	test_must_fail git commit -m second 2>out.commit
diff --git a/t/t0008-ignores.sh b/t/t0008-ignores.sh
index 5575dad..c70d11b 100755
--- a/t/t0008-ignores.sh
+++ b/t/t0008-ignores.sh
@@ -3,6 +3,7 @@
 test_description=check-ignore
 
 TEST_PASSES_SANITIZE_LEAK=true
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 init_vars () {
@@ -225,7 +226,8 @@
 		!globaltwo
 		globalthree
 	EOF
-	cat <<-\EOF >>.git/info/exclude
+	mkdir .git/info &&
+	cat <<-\EOF >.git/info/exclude
 		per-repo
 	EOF
 '
@@ -543,9 +545,9 @@
 
 test_expect_success 'global ignore not yet enabled' '
 	expect_from_stdin <<-\EOF &&
-		.git/info/exclude:7:per-repo	per-repo
+		.git/info/exclude:1:per-repo	per-repo
 		a/.gitignore:2:*three	a/globalthree
-		.git/info/exclude:7:per-repo	a/per-repo
+		.git/info/exclude:1:per-repo	a/per-repo
 	EOF
 	test_check_ignore "-v globalone per-repo a/globalthree a/per-repo not-ignored a/globaltwo"
 '
@@ -566,10 +568,10 @@
 	enable_global_excludes &&
 	expect_from_stdin <<-EOF &&
 		$global_excludes:1:globalone	globalone
-		.git/info/exclude:7:per-repo	per-repo
+		.git/info/exclude:1:per-repo	per-repo
 		$global_excludes:3:globalthree	globalthree
 		a/.gitignore:2:*three	a/globalthree
-		.git/info/exclude:7:per-repo	a/per-repo
+		.git/info/exclude:1:per-repo	a/per-repo
 		$global_excludes:2:!globaltwo	globaltwo
 	EOF
 	test_check_ignore "-v globalone per-repo globalthree a/globalthree a/per-repo not-ignored globaltwo"
diff --git a/t/t0012-help.sh b/t/t0012-help.sh
index 6c33a43..4ed2f24 100755
--- a/t/t0012-help.sh
+++ b/t/t0012-help.sh
@@ -44,6 +44,8 @@
 	test_expect_code 129 git help -g add &&
 	test_expect_code 129 git help -a -g &&
 
+	test_expect_code 129 git help --user-interfaces add &&
+
 	test_expect_code 129 git help -g -c &&
 	test_expect_code 129 git help --config-for-completion add &&
 	test_expect_code 129 git help --config-sections-for-completion add
@@ -104,9 +106,9 @@
 	test_i18ngrep "^   commit " help.output &&
 	test_i18ngrep "^   fetch  " help.output
 '
+
 test_expect_success 'git help -g' '
 	git help -g >help.output &&
-	test_i18ngrep "^   attributes " help.output &&
 	test_i18ngrep "^   everyday   " help.output &&
 	test_i18ngrep "^   tutorial   " help.output
 '
@@ -127,6 +129,12 @@
 	test_cmp expect test-browser.log
 '
 
+test_expect_success 'git help --user-interfaces' '
+	git help --user-interfaces >help.output &&
+	grep "^   attributes   " help.output &&
+	grep "^   mailmap   " help.output
+'
+
 test_expect_success 'git help -c' '
 	git help -c >help.output &&
 	cat >expect <<-\EOF &&
@@ -220,6 +228,10 @@
 	Low-level Commands / Syncing Repositories
 
 	Low-level Commands / Internal Helpers
+
+	User-facing repository, command and file interfaces
+
+	Developer-facing file file formats, protocols and interfaces
 	EOF
 	test_cmp expect actual
 '
diff --git a/t/t0015-hash.sh b/t/t0015-hash.sh
index 086822f..0a087a1 100755
--- a/t/t0015-hash.sh
+++ b/t/t0015-hash.sh
@@ -1,8 +1,9 @@
 #!/bin/sh
 
 test_description='test basic hash implementation'
-. ./test-lib.sh
 
+TEST_PASSES_SANITIZE_LEAK=true
+. ./test-lib.sh
 
 test_expect_success 'test basic SHA-1 hash values' '
 	test-tool sha1 </dev/null >actual &&
diff --git a/t/t0019-json-writer.sh b/t/t0019-json-writer.sh
index 3b0c336..19a730c 100755
--- a/t/t0019-json-writer.sh
+++ b/t/t0019-json-writer.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test json-writer JSON generation'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'unit test of json-writer routines' '
diff --git a/t/t0021-conversion.sh b/t/t0021-conversion.sh
index 1c84034..abecd75 100755
--- a/t/t0021-conversion.sh
+++ b/t/t0021-conversion.sh
@@ -17,9 +17,6 @@
   'nopqrstuvwxyzabcdefghijklmNOPQRSTUVWXYZABCDEFGHIJKLM'
 EOF
 
-write_script rot13-filter.pl "$PERL_PATH" \
-	<"$TEST_DIRECTORY"/t0021/rot13-filter.pl
-
 generate_random_characters () {
 	LEN=$1
 	NAME=$2
@@ -365,8 +362,8 @@
 	test_line_count = 0 count
 '
 
-test_expect_success PERL 'required process filter should filter data' '
-	test_config_global filter.protocol.process "rot13-filter.pl debug.log clean smudge" &&
+test_expect_success 'required process filter should filter data' '
+	test_config_global filter.protocol.process "test-tool rot13-filter --log=debug.log clean smudge" &&
 	test_config_global filter.protocol.required true &&
 	rm -rf repo &&
 	mkdir repo &&
@@ -450,8 +447,8 @@
 	)
 '
 
-test_expect_success PERL 'required process filter should filter data for various subcommands' '
-	test_config_global filter.protocol.process "rot13-filter.pl debug.log clean smudge" &&
+test_expect_success 'required process filter should filter data for various subcommands' '
+	test_config_global filter.protocol.process "test-tool rot13-filter --log=debug.log clean smudge" &&
 	test_config_global filter.protocol.required true &&
 	(
 		cd repo &&
@@ -561,9 +558,9 @@
 	)
 '
 
-test_expect_success PERL 'required process filter takes precedence' '
+test_expect_success 'required process filter takes precedence' '
 	test_config_global filter.protocol.clean false &&
-	test_config_global filter.protocol.process "rot13-filter.pl debug.log clean" &&
+	test_config_global filter.protocol.process "test-tool rot13-filter --log=debug.log clean" &&
 	test_config_global filter.protocol.required true &&
 	rm -rf repo &&
 	mkdir repo &&
@@ -587,8 +584,8 @@
 	)
 '
 
-test_expect_success PERL 'required process filter should be used only for "clean" operation only' '
-	test_config_global filter.protocol.process "rot13-filter.pl debug.log clean" &&
+test_expect_success 'required process filter should be used only for "clean" operation only' '
+	test_config_global filter.protocol.process "test-tool rot13-filter --log=debug.log clean" &&
 	rm -rf repo &&
 	mkdir repo &&
 	(
@@ -622,8 +619,8 @@
 	)
 '
 
-test_expect_success PERL 'required process filter should process multiple packets' '
-	test_config_global filter.protocol.process "rot13-filter.pl debug.log clean smudge" &&
+test_expect_success 'required process filter should process multiple packets' '
+	test_config_global filter.protocol.process "test-tool rot13-filter --log=debug.log clean smudge" &&
 	test_config_global filter.protocol.required true &&
 
 	rm -rf repo &&
@@ -687,8 +684,8 @@
 	)
 '
 
-test_expect_success PERL 'required process filter with clean error should fail' '
-	test_config_global filter.protocol.process "rot13-filter.pl debug.log clean smudge" &&
+test_expect_success 'required process filter with clean error should fail' '
+	test_config_global filter.protocol.process "test-tool rot13-filter --log=debug.log clean smudge" &&
 	test_config_global filter.protocol.required true &&
 	rm -rf repo &&
 	mkdir repo &&
@@ -706,8 +703,8 @@
 	)
 '
 
-test_expect_success PERL 'process filter should restart after unexpected write failure' '
-	test_config_global filter.protocol.process "rot13-filter.pl debug.log clean smudge" &&
+test_expect_success 'process filter should restart after unexpected write failure' '
+	test_config_global filter.protocol.process "test-tool rot13-filter --log=debug.log clean smudge" &&
 	rm -rf repo &&
 	mkdir repo &&
 	(
@@ -735,7 +732,7 @@
 		rm -f debug.log &&
 		git checkout --quiet --no-progress . 2>git-stderr.log &&
 
-		grep "smudge write error at" git-stderr.log &&
+		grep "smudge write error" git-stderr.log &&
 		test_i18ngrep "error: external filter" git-stderr.log &&
 
 		cat >expected.log <<-EOF &&
@@ -761,8 +758,8 @@
 	)
 '
 
-test_expect_success PERL 'process filter should not be restarted if it signals an error' '
-	test_config_global filter.protocol.process "rot13-filter.pl debug.log clean smudge" &&
+test_expect_success 'process filter should not be restarted if it signals an error' '
+	test_config_global filter.protocol.process "test-tool rot13-filter --log=debug.log clean smudge" &&
 	rm -rf repo &&
 	mkdir repo &&
 	(
@@ -804,8 +801,8 @@
 	)
 '
 
-test_expect_success PERL 'process filter abort stops processing of all further files' '
-	test_config_global filter.protocol.process "rot13-filter.pl debug.log clean smudge" &&
+test_expect_success 'process filter abort stops processing of all further files' '
+	test_config_global filter.protocol.process "test-tool rot13-filter --log=debug.log clean smudge" &&
 	rm -rf repo &&
 	mkdir repo &&
 	(
@@ -861,10 +858,10 @@
 	)
 '
 
-test_expect_success PERL 'delayed checkout in process filter' '
-	test_config_global filter.a.process "rot13-filter.pl a.log clean smudge delay" &&
+test_expect_success 'delayed checkout in process filter' '
+	test_config_global filter.a.process "test-tool rot13-filter --log=a.log clean smudge delay" &&
 	test_config_global filter.a.required true &&
-	test_config_global filter.b.process "rot13-filter.pl b.log clean smudge delay" &&
+	test_config_global filter.b.process "test-tool rot13-filter --log=b.log clean smudge delay" &&
 	test_config_global filter.b.required true &&
 
 	rm -rf repo &&
@@ -940,8 +937,8 @@
 	)
 '
 
-test_expect_success PERL 'missing file in delayed checkout' '
-	test_config_global filter.bug.process "rot13-filter.pl bug.log clean smudge delay" &&
+test_expect_success 'missing file in delayed checkout' '
+	test_config_global filter.bug.process "test-tool rot13-filter --log=bug.log clean smudge delay" &&
 	test_config_global filter.bug.required true &&
 
 	rm -rf repo &&
@@ -960,8 +957,8 @@
 	grep "error: .missing-delay\.a. was not filtered properly" git-stderr.log
 '
 
-test_expect_success PERL 'invalid file in delayed checkout' '
-	test_config_global filter.bug.process "rot13-filter.pl bug.log clean smudge delay" &&
+test_expect_success 'invalid file in delayed checkout' '
+	test_config_global filter.bug.process "test-tool rot13-filter --log=bug.log clean smudge delay" &&
 	test_config_global filter.bug.required true &&
 
 	rm -rf repo &&
@@ -990,10 +987,10 @@
 		mode_prereq='UTF8_NFD_TO_NFC' ;;
 	esac
 
-	test_expect_success PERL,SYMLINKS,$mode_prereq \
+	test_expect_success SYMLINKS,$mode_prereq \
 	"delayed checkout with $mode-collision don't write to the wrong place" '
 		test_config_global filter.delay.process \
-			"\"$TEST_ROOT/rot13-filter.pl\" --always-delay delayed.log clean smudge delay" &&
+			"test-tool rot13-filter --always-delay --log=delayed.log clean smudge delay" &&
 		test_config_global filter.delay.required true &&
 
 		git init $mode-collision &&
@@ -1026,12 +1023,12 @@
 	'
 done
 
-test_expect_success PERL,SYMLINKS,CASE_INSENSITIVE_FS \
+test_expect_success SYMLINKS,CASE_INSENSITIVE_FS \
 "delayed checkout with submodule collision don't write to the wrong place" '
 	git init collision-with-submodule &&
 	(
 		cd collision-with-submodule &&
-		git config filter.delay.process "\"$TEST_ROOT/rot13-filter.pl\" --always-delay delayed.log clean smudge delay" &&
+		git config filter.delay.process "test-tool rot13-filter --always-delay --log=delayed.log clean smudge delay" &&
 		git config filter.delay.required true &&
 
 		# We need Git to treat the submodule "a" and the
@@ -1062,11 +1059,11 @@
 	)
 '
 
-test_expect_success PERL 'setup for progress tests' '
+test_expect_success 'setup for progress tests' '
 	git init progress &&
 	(
 		cd progress &&
-		git config filter.delay.process "rot13-filter.pl delay-progress.log clean smudge delay" &&
+		git config filter.delay.process "test-tool rot13-filter --log=delay-progress.log clean smudge delay" &&
 		git config filter.delay.required true &&
 
 		echo "*.a filter=delay" >.gitattributes &&
@@ -1132,12 +1129,12 @@
 	'
 done
 
-test_expect_success PERL 'delayed checkout correctly reports the number of updated entries' '
+test_expect_success 'delayed checkout correctly reports the number of updated entries' '
 	rm -rf repo &&
 	git init repo &&
 	(
 		cd repo &&
-		git config filter.delay.process "../rot13-filter.pl delayed.log clean smudge delay" &&
+		git config filter.delay.process "test-tool rot13-filter --log=delayed.log clean smudge delay" &&
 		git config filter.delay.required true &&
 
 		echo "*.a filter=delay" >.gitattributes &&
diff --git a/t/t0021/rot13-filter.pl b/t/t0021/rot13-filter.pl
deleted file mode 100644
index 7bb9376..0000000
--- a/t/t0021/rot13-filter.pl
+++ /dev/null
@@ -1,247 +0,0 @@
-#
-# Example implementation for the Git filter protocol version 2
-# See Documentation/gitattributes.txt, section "Filter Protocol"
-#
-# Usage: rot13-filter.pl [--always-delay] <log path> <capabilities>
-#
-# Log path defines a debug log file that the script writes to. The
-# subsequent arguments define a list of supported protocol capabilities
-# ("clean", "smudge", etc).
-#
-# When --always-delay is given all pathnames with the "can-delay" flag
-# that don't appear on the list bellow are delayed with a count of 1
-# (see more below).
-#
-# This implementation supports special test cases:
-# (1) If data with the pathname "clean-write-fail.r" is processed with
-#     a "clean" operation then the write operation will die.
-# (2) If data with the pathname "smudge-write-fail.r" is processed with
-#     a "smudge" operation then the write operation will die.
-# (3) If data with the pathname "error.r" is processed with any
-#     operation then the filter signals that it cannot or does not want
-#     to process the file.
-# (4) If data with the pathname "abort.r" is processed with any
-#     operation then the filter signals that it cannot or does not want
-#     to process the file and any file after that is processed with the
-#     same command.
-# (5) If data with a pathname that is a key in the DELAY hash is
-#     requested (e.g. "test-delay10.a") then the filter responds with
-#     a "delay" status and sets the "requested" field in the DELAY hash.
-#     The filter will signal the availability of this object after
-#     "count" (field in DELAY hash) "list_available_blobs" commands.
-# (6) If data with the pathname "missing-delay.a" is processed that the
-#     filter will drop the path from the "list_available_blobs" response.
-# (7) If data with the pathname "invalid-delay.a" is processed that the
-#     filter will add the path "unfiltered" which was not delayed before
-#     to the "list_available_blobs" response.
-#
-
-use 5.008;
-sub gitperllib {
-	# Git assumes that all path lists are Unix-y colon-separated ones. But
-	# when the Git for Windows executes the test suite, its MSYS2 Bash
-	# calls git.exe, and colon-separated path lists are converted into
-	# Windows-y semicolon-separated lists of *Windows* paths (which
-	# naturally contain a colon after the drive letter, so splitting by
-	# colons simply does not cut it).
-	#
-	# Detect semicolon-separated path list and handle them appropriately.
-
-	if ($ENV{GITPERLLIB} =~ /;/) {
-		return split(/;/, $ENV{GITPERLLIB});
-	}
-	return split(/:/, $ENV{GITPERLLIB});
-}
-use lib (gitperllib());
-use strict;
-use warnings;
-use IO::File;
-use Git::Packet;
-
-my $MAX_PACKET_CONTENT_SIZE = 65516;
-
-my $always_delay = 0;
-if ( $ARGV[0] eq '--always-delay' ) {
-	$always_delay = 1;
-	shift @ARGV;
-}
-
-my $log_file                = shift @ARGV;
-my @capabilities            = @ARGV;
-
-open my $debug, ">>", $log_file or die "cannot open log file: $!";
-
-my %DELAY = (
-	'test-delay10.a' => { "requested" => 0, "count" => 1 },
-	'test-delay11.a' => { "requested" => 0, "count" => 1 },
-	'test-delay20.a' => { "requested" => 0, "count" => 2 },
-	'test-delay10.b' => { "requested" => 0, "count" => 1 },
-	'missing-delay.a' => { "requested" => 0, "count" => 1 },
-	'invalid-delay.a' => { "requested" => 0, "count" => 1 },
-);
-
-sub rot13 {
-	my $str = shift;
-	$str =~ y/A-Za-z/N-ZA-Mn-za-m/;
-	return $str;
-}
-
-print $debug "START\n";
-$debug->flush();
-
-packet_initialize("git-filter", 2);
-
-my %remote_caps = packet_read_and_check_capabilities("clean", "smudge", "delay");
-packet_check_and_write_capabilities(\%remote_caps, @capabilities);
-
-print $debug "init handshake complete\n";
-$debug->flush();
-
-while (1) {
-	my ( $res, $command ) = packet_key_val_read("command");
-	if ( $res == -1 ) {
-		print $debug "STOP\n";
-		exit();
-	}
-	print $debug "IN: $command";
-	$debug->flush();
-
-	if ( $command eq "list_available_blobs" ) {
-		# Flush
-		packet_compare_lists([1, ""], packet_bin_read()) ||
-			die "bad list_available_blobs end";
-
-		foreach my $pathname ( sort keys %DELAY ) {
-			if ( $DELAY{$pathname}{"requested"} >= 1 ) {
-				$DELAY{$pathname}{"count"} = $DELAY{$pathname}{"count"} - 1;
-				if ( $pathname eq "invalid-delay.a" ) {
-					# Send Git a pathname that was not delayed earlier
-					packet_txt_write("pathname=unfiltered");
-				}
-				if ( $pathname eq "missing-delay.a" ) {
-					# Do not signal Git that this file is available
-				} elsif ( $DELAY{$pathname}{"count"} == 0 ) {
-					print $debug " $pathname";
-					packet_txt_write("pathname=$pathname");
-				}
-			}
-		}
-
-		packet_flush();
-
-		print $debug " [OK]\n";
-		$debug->flush();
-		packet_txt_write("status=success");
-		packet_flush();
-	} else {
-		my ( $res, $pathname ) = packet_key_val_read("pathname");
-		if ( $res == -1 ) {
-			die "unexpected EOF while expecting pathname";
-		}
-		print $debug " $pathname";
-		$debug->flush();
-
-		# Read until flush
-		my ( $done, $buffer ) = packet_txt_read();
-		while ( $buffer ne '' ) {
-			if ( $buffer eq "can-delay=1" ) {
-				if ( exists $DELAY{$pathname} and $DELAY{$pathname}{"requested"} == 0 ) {
-					$DELAY{$pathname}{"requested"} = 1;
-				} elsif ( !exists $DELAY{$pathname} and $always_delay ) {
-					$DELAY{$pathname} = { "requested" => 1, "count" => 1 };
-				}
-			} elsif ($buffer =~ /^(ref|treeish|blob)=/) {
-				print $debug " $buffer";
-			} else {
-				# In general, filters need to be graceful about
-				# new metadata, since it's documented that we
-				# can pass any key-value pairs, but for tests,
-				# let's be a little stricter.
-				die "Unknown message '$buffer'";
-			}
-
-			( $done, $buffer ) = packet_txt_read();
-		}
-		if ( $done == -1 ) {
-			die "unexpected EOF after pathname '$pathname'";
-		}
-
-		my $input = "";
-		{
-			binmode(STDIN);
-			my $buffer;
-			my $done = 0;
-			while ( !$done ) {
-				( $done, $buffer ) = packet_bin_read();
-				$input .= $buffer;
-			}
-			if ( $done == -1 ) {
-				die "unexpected EOF while reading input for '$pathname'";
-			}			
-			print $debug " " . length($input) . " [OK] -- ";
-			$debug->flush();
-		}
-
-		my $output;
-		if ( exists $DELAY{$pathname} and exists $DELAY{$pathname}{"output"} ) {
-			$output = $DELAY{$pathname}{"output"}
-		} elsif ( $pathname eq "error.r" or $pathname eq "abort.r" ) {
-			$output = "";
-		} elsif ( $command eq "clean" and grep( /^clean$/, @capabilities ) ) {
-			$output = rot13($input);
-		} elsif ( $command eq "smudge" and grep( /^smudge$/, @capabilities ) ) {
-			$output = rot13($input);
-		} else {
-			die "bad command '$command'";
-		}
-
-		if ( $pathname eq "error.r" ) {
-			print $debug "[ERROR]\n";
-			$debug->flush();
-			packet_txt_write("status=error");
-			packet_flush();
-		} elsif ( $pathname eq "abort.r" ) {
-			print $debug "[ABORT]\n";
-			$debug->flush();
-			packet_txt_write("status=abort");
-			packet_flush();
-		} elsif ( $command eq "smudge" and
-			exists $DELAY{$pathname} and
-			$DELAY{$pathname}{"requested"} == 1 ) {
-			print $debug "[DELAYED]\n";
-			$debug->flush();
-			packet_txt_write("status=delayed");
-			packet_flush();
-			$DELAY{$pathname}{"requested"} = 2;
-			$DELAY{$pathname}{"output"} = $output;
-		} else {
-			packet_txt_write("status=success");
-			packet_flush();
-
-			if ( $pathname eq "${command}-write-fail.r" ) {
-				print $debug "[WRITE FAIL]\n";
-				$debug->flush();
-				die "${command} write error";
-			}
-
-			print $debug "OUT: " . length($output) . " ";
-			$debug->flush();
-
-			while ( length($output) > 0 ) {
-				my $packet = substr( $output, 0, $MAX_PACKET_CONTENT_SIZE );
-				packet_bin_write($packet);
-				# dots represent the number of packets
-				print $debug ".";
-				if ( length($output) > $MAX_PACKET_CONTENT_SIZE ) {
-					$output = substr( $output, $MAX_PACKET_CONTENT_SIZE );
-				} else {
-					$output = "";
-				}
-			}
-			packet_flush();
-			print $debug " [OK]\n";
-			$debug->flush();
-			packet_flush();
-		}
-	}
-}
diff --git a/t/t0027-auto-crlf.sh b/t/t0027-auto-crlf.sh
index 7f80f46..a22e0e1 100755
--- a/t/t0027-auto-crlf.sh
+++ b/t/t0027-auto-crlf.sh
@@ -2,6 +2,7 @@
 
 test_description='CRLF conversion all combinations'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 compare_files () {
diff --git a/t/t0028-working-tree-encoding.sh b/t/t0028-working-tree-encoding.sh
index 82905a2..c196fdb 100755
--- a/t/t0028-working-tree-encoding.sh
+++ b/t/t0028-working-tree-encoding.sh
@@ -5,6 +5,8 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 . "$TEST_DIRECTORY/lib-encoding.sh"
 
@@ -69,6 +71,7 @@
 	test_when_finished "rm -f test.utf32.git" &&
 	test_when_finished "git reset --hard HEAD" &&
 
+	mkdir .git/info &&
 	echo "*.utf32 text working-tree-encoding=utf-32" >.git/info/attributes &&
 	git add test.utf32 &&
 
diff --git a/t/t0032-reftable-unittest.sh b/t/t0032-reftable-unittest.sh
index 0ed1497..471cb37 100755
--- a/t/t0032-reftable-unittest.sh
+++ b/t/t0032-reftable-unittest.sh
@@ -5,6 +5,7 @@
 
 test_description='reftable unittests'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'unittests' '
diff --git a/t/t0033-safe-directory.sh b/t/t0033-safe-directory.sh
index 3908597..aecb308 100755
--- a/t/t0033-safe-directory.sh
+++ b/t/t0033-safe-directory.sh
@@ -2,6 +2,7 @@
 
 test_description='verify safe.directory checks'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 GIT_TEST_ASSUME_DIFFERENT_OWNER=1
@@ -16,24 +17,20 @@
 	expect_rejected_dir
 '
 
-test_expect_success 'ignoring safe.directory on the command line' '
-	test_must_fail git -c safe.directory="$(pwd)" status 2>err &&
-	grep "dubious ownership" err
+test_expect_success 'safe.directory on the command line' '
+	git -c safe.directory="$(pwd)" status
 '
 
-test_expect_success 'ignoring safe.directory in the environment' '
-	test_must_fail env GIT_CONFIG_COUNT=1 \
-		GIT_CONFIG_KEY_0="safe.directory" \
-		GIT_CONFIG_VALUE_0="$(pwd)" \
-		git status 2>err &&
-	grep "dubious ownership" err
+test_expect_success 'safe.directory in the environment' '
+	env GIT_CONFIG_COUNT=1 \
+	    GIT_CONFIG_KEY_0="safe.directory" \
+	    GIT_CONFIG_VALUE_0="$(pwd)" \
+	    git status
 '
 
-test_expect_success 'ignoring safe.directory in GIT_CONFIG_PARAMETERS' '
-	test_must_fail env \
-		GIT_CONFIG_PARAMETERS="${SQ}safe.directory${SQ}=${SQ}$(pwd)${SQ}" \
-		git status 2>err &&
-	grep "dubious ownership" err
+test_expect_success 'safe.directory in GIT_CONFIG_PARAMETERS' '
+	env GIT_CONFIG_PARAMETERS="${SQ}safe.directory${SQ}=${SQ}$(pwd)${SQ}" \
+	    git status
 '
 
 test_expect_success 'ignoring safe.directory in repo config' '
diff --git a/t/t0035-safe-bare-repository.sh b/t/t0035-safe-bare-repository.sh
new file mode 100755
index 0000000..ecbdc82
--- /dev/null
+++ b/t/t0035-safe-bare-repository.sh
@@ -0,0 +1,54 @@
+#!/bin/sh
+
+test_description='verify safe.bareRepository checks'
+
+TEST_PASSES_SANITIZE_LEAK=true
+. ./test-lib.sh
+
+pwd="$(pwd)"
+
+expect_accepted () {
+	git "$@" rev-parse --git-dir
+}
+
+expect_rejected () {
+	test_must_fail git "$@" rev-parse --git-dir 2>err &&
+	grep -F "cannot use bare repository" err
+}
+
+test_expect_success 'setup bare repo in worktree' '
+	git init outer-repo &&
+	git init --bare outer-repo/bare-repo
+'
+
+test_expect_success 'safe.bareRepository unset' '
+	expect_accepted -C outer-repo/bare-repo
+'
+
+test_expect_success 'safe.bareRepository=all' '
+	test_config_global safe.bareRepository all &&
+	expect_accepted -C outer-repo/bare-repo
+'
+
+test_expect_success 'safe.bareRepository=explicit' '
+	test_config_global safe.bareRepository explicit &&
+	expect_rejected -C outer-repo/bare-repo
+'
+
+test_expect_success 'safe.bareRepository in the repository' '
+	# safe.bareRepository must not be "explicit", otherwise
+	# git config fails with "fatal: not in a git directory" (like
+	# safe.directory)
+	test_config -C outer-repo/bare-repo safe.bareRepository \
+		all &&
+	test_config_global safe.bareRepository explicit &&
+	expect_rejected -C outer-repo/bare-repo
+'
+
+test_expect_success 'safe.bareRepository on the command line' '
+	test_config_global safe.bareRepository explicit &&
+	expect_accepted -C outer-repo/bare-repo \
+		-c safe.bareRepository=all
+'
+
+test_done
diff --git a/t/t0040-parse-options.sh b/t/t0040-parse-options.sh
index ed2fb62..5cc6230 100755
--- a/t/t0040-parse-options.sh
+++ b/t/t0040-parse-options.sh
@@ -456,4 +456,257 @@
 	    --end-of-options --verbose
 '
 
+test_expect_success 'KEEP_DASHDASH works' '
+	test-tool parse-options-flags --keep-dashdash cmd --opt=1 -- --opt=2 --unknown >actual &&
+	cat >expect <<-\EOF &&
+	opt: 1
+	arg 00: --
+	arg 01: --opt=2
+	arg 02: --unknown
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'KEEP_ARGV0 works' '
+	test-tool parse-options-flags --keep-argv0 cmd arg0 --opt=3 >actual &&
+	cat >expect <<-\EOF &&
+	opt: 3
+	arg 00: cmd
+	arg 01: arg0
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'STOP_AT_NON_OPTION works' '
+	test-tool parse-options-flags --stop-at-non-option cmd --opt=4 arg0 --opt=5 --unknown >actual &&
+	cat >expect <<-\EOF &&
+	opt: 4
+	arg 00: arg0
+	arg 01: --opt=5
+	arg 02: --unknown
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'KEEP_UNKNOWN_OPT works' '
+	test-tool parse-options-flags --keep-unknown-opt cmd --unknown=1 --opt=6 -u2 >actual &&
+	cat >expect <<-\EOF &&
+	opt: 6
+	arg 00: --unknown=1
+	arg 01: -u2
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'NO_INTERNAL_HELP works for -h' '
+	test_expect_code 129 test-tool parse-options-flags --no-internal-help cmd -h 2>err &&
+	grep "^error: unknown switch \`h$SQ" err &&
+	grep "^usage: " err
+'
+
+for help_opt in help help-all
+do
+	test_expect_success "NO_INTERNAL_HELP works for --$help_opt" "
+		test_expect_code 129 test-tool parse-options-flags --no-internal-help cmd --$help_opt 2>err &&
+		grep '^error: unknown option \`'$help_opt\' err &&
+		grep '^usage: ' err
+	"
+done
+
+test_expect_success 'KEEP_UNKNOWN_OPT | NO_INTERNAL_HELP works' '
+	test-tool parse-options-flags --keep-unknown-opt --no-internal-help cmd -h --help --help-all >actual &&
+	cat >expect <<-\EOF &&
+	opt: 0
+	arg 00: -h
+	arg 01: --help
+	arg 02: --help-all
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - no subcommand shows error and usage' '
+	test_expect_code 129 test-tool parse-subcommand cmd 2>err &&
+	grep "^error: need a subcommand" err &&
+	grep ^usage: err
+'
+
+test_expect_success 'subcommand - subcommand after -- shows error and usage' '
+	test_expect_code 129 test-tool parse-subcommand cmd -- subcmd-one 2>err &&
+	grep "^error: need a subcommand" err &&
+	grep ^usage: err
+'
+
+test_expect_success 'subcommand - subcommand after --end-of-options shows error and usage' '
+	test_expect_code 129 test-tool parse-subcommand cmd --end-of-options subcmd-one 2>err &&
+	grep "^error: need a subcommand" err &&
+	grep ^usage: err
+'
+
+test_expect_success 'subcommand - unknown subcommand shows error and usage' '
+	test_expect_code 129 test-tool parse-subcommand cmd nope 2>err &&
+	grep "^error: unknown subcommand: \`nope$SQ" err &&
+	grep ^usage: err
+'
+
+test_expect_success 'subcommand - subcommands cannot be abbreviated' '
+	test_expect_code 129 test-tool parse-subcommand cmd subcmd-o 2>err &&
+	grep "^error: unknown subcommand: \`subcmd-o$SQ$" err &&
+	grep ^usage: err
+'
+
+test_expect_success 'subcommand - no negated subcommands' '
+	test_expect_code 129 test-tool parse-subcommand cmd no-subcmd-one 2>err &&
+	grep "^error: unknown subcommand: \`no-subcmd-one$SQ" err &&
+	grep ^usage: err
+'
+
+test_expect_success 'subcommand - simple' '
+	test-tool parse-subcommand cmd subcmd-two >actual &&
+	cat >expect <<-\EOF &&
+	opt: 0
+	fn: subcmd_two
+	arg 00: subcmd-two
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - stop parsing at the first subcommand' '
+	test-tool parse-subcommand cmd --opt=1 subcmd-two subcmd-one --opt=2 >actual &&
+	cat >expect <<-\EOF &&
+	opt: 1
+	fn: subcmd_two
+	arg 00: subcmd-two
+	arg 01: subcmd-one
+	arg 02: --opt=2
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - KEEP_ARGV0' '
+	test-tool parse-subcommand --keep-argv0 cmd subcmd-two >actual &&
+	cat >expect <<-\EOF &&
+	opt: 0
+	fn: subcmd_two
+	arg 00: cmd
+	arg 01: subcmd-two
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL + subcommand not given' '
+	test-tool parse-subcommand --subcommand-optional cmd >actual &&
+	cat >expect <<-\EOF &&
+	opt: 0
+	fn: subcmd_one
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL + given subcommand' '
+	test-tool parse-subcommand --subcommand-optional cmd subcmd-two branch file >actual &&
+	cat >expect <<-\EOF &&
+	opt: 0
+	fn: subcmd_two
+	arg 00: subcmd-two
+	arg 01: branch
+	arg 02: file
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL + subcommand not given + unknown dashless args' '
+	test-tool parse-subcommand --subcommand-optional cmd branch file >actual &&
+	cat >expect <<-\EOF &&
+	opt: 0
+	fn: subcmd_one
+	arg 00: branch
+	arg 01: file
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL + subcommand not given + unknown option' '
+	test_expect_code 129 test-tool parse-subcommand --subcommand-optional cmd --subcommand-opt 2>err &&
+	grep "^error: unknown option" err &&
+	grep ^usage: err
+'
+
+test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL | KEEP_UNKNOWN_OPT + subcommand not given + unknown option' '
+	test-tool parse-subcommand --subcommand-optional --keep-unknown-opt cmd --subcommand-opt >actual &&
+	cat >expect <<-\EOF &&
+	opt: 0
+	fn: subcmd_one
+	arg 00: --subcommand-opt
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL | KEEP_UNKNOWN_OPT + subcommand ignored after unknown option' '
+	test-tool parse-subcommand --subcommand-optional --keep-unknown-opt cmd --subcommand-opt subcmd-two >actual &&
+	cat >expect <<-\EOF &&
+	opt: 0
+	fn: subcmd_one
+	arg 00: --subcommand-opt
+	arg 01: subcmd-two
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL | KEEP_UNKNOWN_OPT + command and subcommand options cannot be mixed' '
+	test-tool parse-subcommand --subcommand-optional --keep-unknown-opt cmd --subcommand-opt branch --opt=1 >actual &&
+	cat >expect <<-\EOF &&
+	opt: 0
+	fn: subcmd_one
+	arg 00: --subcommand-opt
+	arg 01: branch
+	arg 02: --opt=1
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL | KEEP_UNKNOWN_OPT | KEEP_ARGV0' '
+	test-tool parse-subcommand --subcommand-optional --keep-unknown-opt --keep-argv0 cmd --subcommand-opt branch >actual &&
+	cat >expect <<-\EOF &&
+	opt: 0
+	fn: subcmd_one
+	arg 00: cmd
+	arg 01: --subcommand-opt
+	arg 02: branch
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - SUBCOMMAND_OPTIONAL | KEEP_UNKNOWN_OPT | KEEP_DASHDASH' '
+	test-tool parse-subcommand --subcommand-optional --keep-unknown-opt --keep-dashdash cmd -- --subcommand-opt file >actual &&
+	cat >expect <<-\EOF &&
+	opt: 0
+	fn: subcmd_one
+	arg 00: --
+	arg 01: --subcommand-opt
+	arg 02: file
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommand - completion helper' '
+	test-tool parse-subcommand cmd --git-completion-helper >actual &&
+	echo "subcmd-one subcmd-two --opt= --no-opt" >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'subcommands are incompatible with STOP_AT_NON_OPTION' '
+	test_must_fail test-tool parse-subcommand --stop-at-non-option cmd subcmd-one 2>err &&
+	grep ^BUG err
+'
+
+test_expect_success 'subcommands are incompatible with KEEP_UNKNOWN_OPT unless in combination with SUBCOMMAND_OPTIONAL' '
+	test_must_fail test-tool parse-subcommand --keep-unknown-opt cmd subcmd-two 2>err &&
+	grep ^BUG err
+'
+
+test_expect_success 'subcommands are incompatible with KEEP_DASHDASH unless in combination with SUBCOMMAND_OPTIONAL' '
+	test_must_fail test-tool parse-subcommand --keep-dashdash cmd subcmd-two 2>err &&
+	grep ^BUG err
+'
+
 test_done
diff --git a/t/t0050-filesystem.sh b/t/t0050-filesystem.sh
index 5c9dc90..325eb1c 100755
--- a/t/t0050-filesystem.sh
+++ b/t/t0050-filesystem.sh
@@ -5,6 +5,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 auml=$(printf '\303\244')
diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
index aa35350..68e29c9 100755
--- a/t/t0060-path-utils.sh
+++ b/t/t0060-path-utils.sh
@@ -5,6 +5,7 @@
 
 test_description='Test various path utilities'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 norm_path() {
@@ -21,7 +22,7 @@
 
 test_submodule_relative_url() {
 	test_expect_success "test_submodule_relative_url: $1 $2 $3 => $4" "
-		actual=\$(git submodule--helper resolve-relative-url-test '$1' '$2' '$3') &&
+		actual=\$(test-tool submodule resolve-relative-url '$1' '$2' '$3') &&
 		test \"\$actual\" = '$4'
 	"
 }
diff --git a/t/t0071-sort.sh b/t/t0071-sort.sh
index 6f9a501..ba8ad1d 100755
--- a/t/t0071-sort.sh
+++ b/t/t0071-sort.sh
@@ -5,7 +5,7 @@
 TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
-test_expect_success 'llist_mergesort()' '
+test_expect_success 'DEFINE_LIST_SORT_DEBUG' '
 	test-tool mergesort test
 '
 
diff --git a/t/t0090-cache-tree.sh b/t/t0090-cache-tree.sh
index 9067572..d8e2fc4 100755
--- a/t/t0090-cache-tree.sh
+++ b/t/t0090-cache-tree.sh
@@ -5,6 +5,8 @@
 Tests whether various commands properly update and/or rewrite the
 cache-tree extension.
 "
+
+TEST_PASSES_SANITIZE_LEAK=true
  . ./test-lib.sh
 
 cmp_cache_tree () {
diff --git a/t/t0091-bugreport.sh b/t/t0091-bugreport.sh
index 08f5fe9..b6d2f59 100755
--- a/t/t0091-bugreport.sh
+++ b/t/t0091-bugreport.sh
@@ -78,4 +78,52 @@
 	test_cmp expect actual
 '
 
+test_expect_success UNZIP '--diagnose creates diagnostics zip archive' '
+	test_when_finished rm -rf report &&
+
+	git bugreport --diagnose -o report -s test >out &&
+
+	zip_path=report/git-diagnostics-test.zip &&
+	grep "Available space" out &&
+	test_path_is_file "$zip_path" &&
+
+	# Check zipped archive content
+	"$GIT_UNZIP" -p "$zip_path" diagnostics.log >out &&
+	test_file_not_empty out &&
+
+	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
+	grep ".git/objects" out &&
+
+	"$GIT_UNZIP" -p "$zip_path" objects-local.txt >out &&
+	grep "^Total: [0-9][0-9]*" out &&
+
+	# Should not include .git directory contents by default
+	! "$GIT_UNZIP" -l "$zip_path" | grep ".git/"
+'
+
+test_expect_success UNZIP '--diagnose=stats excludes .git dir contents' '
+	test_when_finished rm -rf report &&
+
+	git bugreport --diagnose=stats -o report -s test >out &&
+
+	# Includes pack quantity/size info
+	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
+	grep ".git/objects" out &&
+
+	# Does not include .git directory contents
+	! "$GIT_UNZIP" -l "$zip_path" | grep ".git/"
+'
+
+test_expect_success UNZIP '--diagnose=all includes .git dir contents' '
+	test_when_finished rm -rf report &&
+
+	git bugreport --diagnose=all -o report -s test >out &&
+
+	# Includes .git directory contents
+	"$GIT_UNZIP" -l "$zip_path" | grep ".git/" &&
+
+	"$GIT_UNZIP" -p "$zip_path" .git/HEAD >out &&
+	test_file_not_empty out
+'
+
 test_done
diff --git a/t/t0092-diagnose.sh b/t/t0092-diagnose.sh
new file mode 100755
index 0000000..fca9b58
--- /dev/null
+++ b/t/t0092-diagnose.sh
@@ -0,0 +1,60 @@
+#!/bin/sh
+
+test_description='git diagnose'
+
+TEST_PASSES_SANITIZE_LEAK=true
+. ./test-lib.sh
+
+test_expect_success UNZIP 'creates diagnostics zip archive' '
+	test_when_finished rm -rf report &&
+
+	git diagnose -o report -s test >out &&
+	grep "Available space" out &&
+
+	zip_path=report/git-diagnostics-test.zip &&
+	test_path_is_file "$zip_path" &&
+
+	# Check zipped archive content
+	"$GIT_UNZIP" -p "$zip_path" diagnostics.log >out &&
+	test_file_not_empty out &&
+
+	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
+	grep ".git/objects" out &&
+
+	"$GIT_UNZIP" -p "$zip_path" objects-local.txt >out &&
+	grep "^Total: [0-9][0-9]*" out &&
+
+	# Should not include .git directory contents by default
+	! "$GIT_UNZIP" -l "$zip_path" | grep ".git/"
+'
+
+test_expect_success UNZIP '--mode=stats excludes .git dir contents' '
+	test_when_finished rm -rf report &&
+
+	git diagnose -o report -s test --mode=stats >out &&
+
+	# Includes pack quantity/size info
+	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
+	grep ".git/objects" out &&
+
+	# Does not include .git directory contents
+	! "$GIT_UNZIP" -l "$zip_path" | grep ".git/"
+'
+
+test_expect_success UNZIP '--mode=all includes .git dir contents' '
+	test_when_finished rm -rf report &&
+
+	git diagnose -o report -s test --mode=all >out &&
+
+	# Includes pack quantity/size info
+	"$GIT_UNZIP" -p "$zip_path" packs-local.txt >out &&
+	grep ".git/objects" out &&
+
+	# Includes .git directory contents
+	"$GIT_UNZIP" -l "$zip_path" | grep ".git/" &&
+
+	"$GIT_UNZIP" -p "$zip_path" .git/HEAD >out &&
+	test_file_not_empty out
+'
+
+test_done
diff --git a/t/t0095-bloom.sh b/t/t0095-bloom.sh
index 5945973..b567383 100755
--- a/t/t0095-bloom.sh
+++ b/t/t0095-bloom.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='Testing the various Bloom filter computations in bloom.c'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'compute unseeded murmur3 hash for empty string' '
@@ -67,7 +69,7 @@
 	test_cmp expect actual
 '
 
-test_expect_success 'get bloom filters for commit with no changes' '
+test_expect_success !SANITIZE_LEAK 'get bloom filters for commit with no changes' '
 	git init &&
 	git commit --allow-empty -m "c0" &&
 	cat >expect <<-\EOF &&
diff --git a/t/t0110-urlmatch-normalization.sh b/t/t0110-urlmatch-normalization.sh
index 4dc9fec..12d817f 100755
--- a/t/t0110-urlmatch-normalization.sh
+++ b/t/t0110-urlmatch-normalization.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='urlmatch URL normalization'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # The base name of the test url files
diff --git a/t/t0202-gettext-perl.sh b/t/t0202-gettext-perl.sh
index df2ea34..5a6f280 100755
--- a/t/t0202-gettext-perl.sh
+++ b/t/t0202-gettext-perl.sh
@@ -7,22 +7,12 @@
 
 TEST_PASSES_SANITIZE_LEAK=true
 . ./lib-gettext.sh
+. "$TEST_DIRECTORY"/lib-perl.sh
+skip_all_if_no_Test_More
 
-if ! test_have_prereq PERL; then
-	skip_all='skipping perl interface tests, perl not available'
-	test_done
-fi
-
-perl -MTest::More -e 0 2>/dev/null || {
-	skip_all="Perl Test::More unavailable, skipping test"
-	test_done
-}
-
-# The external test will outputs its own plan
-test_external_has_tap=1
-
-test_external_without_stderr \
-    'Perl Git::I18N API' \
-    perl "$TEST_DIRECTORY"/t0202/test.pl
+test_expect_success 'run t0202/test.pl to test Git::I18N.pm' '
+	"$PERL_PATH" "$TEST_DIRECTORY"/t0202/test.pl 2>stderr &&
+	test_must_be_empty stderr
+'
 
 test_done
diff --git a/t/t0203-gettext-setlocale-sanity.sh b/t/t0203-gettext-setlocale-sanity.sh
index 0ce1f22..86cff32 100755
--- a/t/t0203-gettext-setlocale-sanity.sh
+++ b/t/t0203-gettext-setlocale-sanity.sh
@@ -5,6 +5,7 @@
 
 test_description="The Git C functions aren't broken by setlocale(3)"
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./lib-gettext.sh
 
 test_expect_success 'git show a ISO-8859-1 commit under C locale' '
diff --git a/t/t0212/parse_events.perl b/t/t0212/parse_events.perl
index b640856..30a9f51 100644
--- a/t/t0212/parse_events.perl
+++ b/t/t0212/parse_events.perl
@@ -216,12 +216,19 @@
 
     elsif ($event eq 'data') {
 	my $cat = $line->{'category'};
-	if ($cat eq 'test_category') {
-	    
-	    my $key = $line->{'key'};
-	    my $value = $line->{'value'};
-	    $processes->{$sid}->{'data'}->{$cat}->{$key} = $value;
-	}
+	my $key = $line->{'key'};
+	my $value = $line->{'value'};
+	$processes->{$sid}->{'data'}->{$cat}->{$key} = $value;
+    }
+
+    elsif ($event eq 'data_json') {
+	# NEEDSWORK: Ignore due to
+	# compat/win32/trace2_win32_process_info.c, which should log a
+	# "cmd_ancestry" event instead.
+    }
+
+    else {
+	push @{$processes->{$sid}->{$event}} => $line->{value};
     }
 
     # This trace2 target does not emit 'printf' events.
diff --git a/t/t1006-cat-file.sh b/t/t1006-cat-file.sh
index dadf3b1..23b8942 100755
--- a/t/t1006-cat-file.sh
+++ b/t/t1006-cat-file.sh
@@ -88,7 +88,8 @@
 
 for opt in --buffer \
 	--follow-symlinks \
-	--batch-all-objects
+	--batch-all-objects \
+	-z
 do
 	test_expect_success "usage: bad option combination: $opt without batch mode" '
 		test_incompatible_usage git cat-file $opt &&
@@ -100,6 +101,10 @@
     printf '%s' "$*"
 }
 
+echo_without_newline_nul () {
+	echo_without_newline "$@" | tr '\n' '\0'
+}
+
 strlen () {
     echo_without_newline "$1" | wc -c | sed -e 's/^ *//'
 }
@@ -398,6 +403,12 @@
 	test "$(maybe_remove_timestamp "$batch_output" 1)" = "$(maybe_remove_timestamp "$(echo_without_newline "$batch_input" | git cat-file --batch)" 1)"
 '
 
+test_expect_success '--batch, -z with multiple sha1s gives correct format' '
+	echo_without_newline_nul "$batch_input" >in &&
+	test "$(maybe_remove_timestamp "$batch_output" 1)" = \
+	"$(maybe_remove_timestamp "$(git cat-file --batch -z <in)" 1)"
+'
+
 batch_check_input="$hello_sha1
 $tree_sha1
 $commit_sha1
@@ -418,6 +429,30 @@
     "$(echo_without_newline "$batch_check_input" | git cat-file --batch-check)"
 '
 
+test_expect_success "--batch-check, -z with multiple sha1s gives correct format" '
+    echo_without_newline_nul "$batch_check_input" >in &&
+    test "$batch_check_output" = "$(git cat-file --batch-check -z <in)"
+'
+
+test_expect_success FUNNYNAMES '--batch-check, -z with newline in input' '
+	touch -- "newline${LF}embedded" &&
+	git add -- "newline${LF}embedded" &&
+	git commit -m "file with newline embedded" &&
+	test_tick &&
+
+	printf "HEAD:newline${LF}embedded" >in &&
+	git cat-file --batch-check -z <in >actual &&
+
+	echo "$(git rev-parse "HEAD:newline${LF}embedded") blob 0" >expect &&
+	test_cmp expect actual
+'
+
+batch_command_multiple_info="info $hello_sha1
+info $tree_sha1
+info $commit_sha1
+info $tag_sha1
+info deadbeef"
+
 test_expect_success '--batch-command with multiple info calls gives correct format' '
 	cat >expect <<-EOF &&
 	$hello_sha1 blob $hello_size
@@ -427,17 +462,23 @@
 	deadbeef missing
 	EOF
 
-	git cat-file --batch-command --buffer >actual <<-EOF &&
-	info $hello_sha1
-	info $tree_sha1
-	info $commit_sha1
-	info $tag_sha1
-	info deadbeef
-	EOF
+	echo "$batch_command_multiple_info" >in &&
+	git cat-file --batch-command --buffer <in >actual &&
+
+	test_cmp expect actual &&
+
+	echo "$batch_command_multiple_info" | tr "\n" "\0" >in &&
+	git cat-file --batch-command --buffer -z <in >actual &&
 
 	test_cmp expect actual
 '
 
+batch_command_multiple_contents="contents $hello_sha1
+contents $commit_sha1
+contents $tag_sha1
+contents deadbeef
+flush"
+
 test_expect_success '--batch-command with multiple command calls gives correct format' '
 	remove_timestamp >expect <<-EOF &&
 	$hello_sha1 blob $hello_size
@@ -449,13 +490,14 @@
 	deadbeef missing
 	EOF
 
-	git cat-file --batch-command --buffer >actual_raw <<-EOF &&
-	contents $hello_sha1
-	contents $commit_sha1
-	contents $tag_sha1
-	contents deadbeef
-	flush
-	EOF
+	echo "$batch_command_multiple_contents" >in &&
+	git cat-file --batch-command --buffer <in >actual_raw &&
+
+	remove_timestamp <actual_raw >actual &&
+	test_cmp expect actual &&
+
+	echo "$batch_command_multiple_contents" | tr "\n" "\0" >in &&
+	git cat-file --batch-command --buffer -z <in >actual_raw &&
 
 	remove_timestamp <actual_raw >actual &&
 	test_cmp expect actual
diff --git a/t/t1011-read-tree-sparse-checkout.sh b/t/t1011-read-tree-sparse-checkout.sh
index 63a553d..742f0fa 100755
--- a/t/t1011-read-tree-sparse-checkout.sh
+++ b/t/t1011-read-tree-sparse-checkout.sh
@@ -11,6 +11,7 @@
   A	init.t
 '
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-read-tree.sh
 
@@ -53,6 +54,7 @@
 '
 
 test_expect_success 'read-tree with .git/info/sparse-checkout but disabled' '
+	mkdir .git/info &&
 	echo >.git/info/sparse-checkout &&
 	read_tree_u_must_succeed -m -u HEAD &&
 	git ls-files -t >result &&
diff --git a/t/t1020-subdirectory.sh b/t/t1020-subdirectory.sh
index 9fdbb2a..45eef94 100755
--- a/t/t1020-subdirectory.sh
+++ b/t/t1020-subdirectory.sh
@@ -6,6 +6,7 @@
 test_description='Try various core-level commands in subdirectory.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-read-tree.sh
 
diff --git a/t/t1051-large-conversion.sh b/t/t1051-large-conversion.sh
index 042b0e4..f6709c9 100755
--- a/t/t1051-large-conversion.sh
+++ b/t/t1051-large-conversion.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test conversion filters on large files'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 set_attr() {
diff --git a/t/t1060-object-corruption.sh b/t/t1060-object-corruption.sh
index 5b8e47e..35261af 100755
--- a/t/t1060-object-corruption.sh
+++ b/t/t1060-object-corruption.sh
@@ -139,4 +139,11 @@
 	)
 '
 
+test_expect_success 'partial clone of corrupted repository' '
+	test_config -C misnamed uploadpack.allowFilter true &&
+	git clone --no-local --no-checkout --filter=blob:none \
+		misnamed corrupt-partial && \
+	test_must_fail git -C corrupt-partial checkout --force
+'
+
 test_done
diff --git a/t/t1090-sparse-checkout-scope.sh b/t/t1090-sparse-checkout-scope.sh
index d1833c0..3a14218 100755
--- a/t/t1090-sparse-checkout-scope.sh
+++ b/t/t1090-sparse-checkout-scope.sh
@@ -5,6 +5,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 test_expect_success 'setup' '
@@ -25,6 +26,7 @@
 
 test_expect_success 'perform sparse checkout of main' '
 	git config --local --bool core.sparsecheckout true &&
+	mkdir .git/info &&
 	echo "!/*" >.git/info/sparse-checkout &&
 	echo "/a" >>.git/info/sparse-checkout &&
 	echo "/c" >>.git/info/sparse-checkout &&
@@ -73,7 +75,7 @@
 
 test_expect_success 'in partial clone, sparse checkout only fetches needed blobs' '
 	test_create_repo server &&
-	git clone "file://$(pwd)/server" client &&
+	git clone --template= "file://$(pwd)/server" client &&
 
 	test_config -C server uploadpack.allowfilter 1 &&
 	test_config -C server uploadpack.allowanysha1inwant 1 &&
@@ -85,6 +87,7 @@
 	git -C server commit -m message &&
 
 	test_config -C client core.sparsecheckout 1 &&
+	mkdir client/.git/info &&
 	echo "!/*" >client/.git/info/sparse-checkout &&
 	echo "/a" >>client/.git/info/sparse-checkout &&
 	git -C client fetch --filter=blob:none origin &&
diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh
index 5dced39..b9350c0 100755
--- a/t/t1092-sparse-checkout-compatibility.sh
+++ b/t/t1092-sparse-checkout-compatibility.sh
@@ -380,6 +380,15 @@
 	test_all_match git checkout base
 '
 
+test_expect_success 'checkout orphan then non-orphan' '
+	init_repos &&
+
+	test_all_match git checkout --orphan test-orphan &&
+	test_all_match git status --porcelain=v2 &&
+	test_all_match git checkout base &&
+	test_all_match git status --porcelain=v2
+'
+
 test_expect_success 'add outside sparse cone' '
 	init_repos &&
 
@@ -556,7 +565,7 @@
 			deep/deeper1/a \
 			deep/deeper1/deepest/a
 	do
-		test_all_match git blame $file
+		test_all_match git blame $file || return 1
 	done
 '
 
@@ -567,7 +576,7 @@
 	init_repos &&
 	test_sparse_match git sparse-checkout set &&
 
-	for file in a \
+	for file in \
 			deep/a \
 			deep/deeper1/a \
 			deep/deeper1/deepest/a
@@ -579,7 +588,7 @@
 		# We compare sparse-checkout-err and sparse-index-err in
 		# `test_sparse_match`. Given we know they are the same, we
 		# only check the content of sparse-index-err here.
-		test_cmp expect sparse-index-err
+		test_cmp expect sparse-index-err || return 1
 	done
 '
 
@@ -937,7 +946,7 @@
 	test_all_match git read-tree --prefix=deep/deeper1/deepest -u deepest &&
 	test_all_match git status --porcelain=v2 &&
 
-	test_all_match git rm -rf --sparse folder1/ &&
+	run_on_all git rm -rf --sparse folder1/ &&
 	test_all_match git read-tree --prefix=folder1/ -u update-folder1 &&
 	test_all_match git status --porcelain=v2 &&
 
@@ -1365,10 +1374,14 @@
 		shift &&
 		test_must_fail env \
 			GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
-			git -C sparse-index "$@" || return 1
+			git -C sparse-index "$@" \
+			>sparse-index-out \
+			2>sparse-index-error || return 1
 	else
 		GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
-			git -C sparse-index "$@" || return 1
+			git -C sparse-index "$@" \
+			>sparse-index-out \
+			2>sparse-index-error || return 1
 	fi &&
 	test_region ! index ensure_full_index trace2.txt
 }
@@ -1567,7 +1580,7 @@
 			deep/deeper1/a \
 			deep/deeper1/deepest/a
 	do
-		ensure_not_expanded blame $file
+		ensure_not_expanded blame $file || return 1
 	done
 '
 
@@ -1853,4 +1866,119 @@
 	test_cmp full-checkout-err sparse-index-err
 '
 
+test_expect_success 'mv directory from out-of-cone to in-cone' '
+	init_repos &&
+
+	# <source> as a sparse directory (or SKIP_WORKTREE_DIR without enabling
+	# sparse index).
+	test_all_match git mv --sparse folder1 deep &&
+	test_all_match git status --porcelain=v2 &&
+	test_sparse_match git ls-files -t &&
+	git -C sparse-checkout ls-files -t >actual &&
+	grep -e "H deep/folder1/0/0/0" actual &&
+	grep -e "H deep/folder1/0/1" actual &&
+	grep -e "H deep/folder1/a" actual &&
+
+	test_all_match git reset --hard &&
+
+	# <source> as a directory deeper than sparse index boundary (where
+	# sparse index will expand).
+	test_sparse_match git mv --sparse folder1/0 deep &&
+	test_sparse_match git status --porcelain=v2 &&
+	test_sparse_match git ls-files -t &&
+	git -C sparse-checkout ls-files -t >actual &&
+	grep -e "H deep/0/0/0" actual &&
+	grep -e "H deep/0/1" actual
+'
+
+test_expect_success 'rm pathspec inside sparse definition' '
+	init_repos &&
+
+	test_all_match git rm deep/a &&
+	test_all_match git status --porcelain=v2 &&
+
+	# test wildcard
+	run_on_all git reset --hard &&
+	test_all_match git rm deep/* &&
+	test_all_match git status --porcelain=v2 &&
+
+	# test recursive rm
+	run_on_all git reset --hard &&
+	test_all_match git rm -r deep &&
+	test_all_match git status --porcelain=v2
+'
+
+test_expect_success 'rm pathspec outside sparse definition' '
+	init_repos &&
+
+	for file in folder1/a folder1/0/1
+	do
+		test_sparse_match test_must_fail git rm $file &&
+		test_sparse_match test_must_fail git rm --cached $file &&
+		test_sparse_match git rm --sparse $file &&
+		test_sparse_match git status --porcelain=v2 || return 1
+	done &&
+
+	cat >folder1-full <<-EOF &&
+	rm ${SQ}folder1/0/0/0${SQ}
+	rm ${SQ}folder1/0/1${SQ}
+	rm ${SQ}folder1/a${SQ}
+	EOF
+
+	cat >folder1-sparse <<-EOF &&
+	rm ${SQ}folder1/${SQ}
+	EOF
+
+	# test wildcard
+	run_on_sparse git reset --hard &&
+	run_on_sparse git sparse-checkout reapply &&
+	test_sparse_match test_must_fail git rm folder1/* &&
+	run_on_sparse git rm --sparse folder1/* &&
+	test_cmp folder1-full sparse-checkout-out &&
+	test_cmp folder1-sparse sparse-index-out &&
+	test_sparse_match git status --porcelain=v2 &&
+
+	# test recursive rm
+	run_on_sparse git reset --hard &&
+	run_on_sparse git sparse-checkout reapply &&
+	test_sparse_match test_must_fail git rm --sparse folder1 &&
+	run_on_sparse git rm --sparse -r folder1 &&
+	test_cmp folder1-full sparse-checkout-out &&
+	test_cmp folder1-sparse sparse-index-out &&
+	test_sparse_match git status --porcelain=v2
+'
+
+test_expect_success 'rm pathspec expands index when necessary' '
+	init_repos &&
+
+	# in-cone pathspec (do not expand)
+	ensure_not_expanded rm "deep/deep*" &&
+	test_must_be_empty sparse-index-err &&
+
+	# out-of-cone pathspec (expand)
+	! ensure_not_expanded rm --sparse "folder1/a*" &&
+	test_must_be_empty sparse-index-err &&
+
+	# pathspec that should expand index
+	! ensure_not_expanded rm "*/a" &&
+	test_must_be_empty sparse-index-err &&
+
+	! ensure_not_expanded rm "**a" &&
+	test_must_be_empty sparse-index-err
+'
+
+test_expect_success 'sparse index is not expanded: rm' '
+	init_repos &&
+
+	ensure_not_expanded rm deep/a &&
+
+	# test in-cone wildcard
+	git -C sparse-index reset --hard &&
+	ensure_not_expanded rm deep/* &&
+
+	# test recursive rm
+	git -C sparse-index reset --hard &&
+	ensure_not_expanded rm -r deep
+'
+
 test_done
diff --git a/t/t1301-shared-repo.sh b/t/t1301-shared-repo.sh
index 84bf197..93a2f91 100755
--- a/t/t1301-shared-repo.sh
+++ b/t/t1301-shared-repo.sh
@@ -48,7 +48,7 @@
 test_expect_success 'shared=all' '
 	mkdir sub &&
 	cd sub &&
-	git init --shared=all &&
+	git init --template= --shared=all &&
 	test 2 = $(git config core.sharedrepository)
 '
 
@@ -57,6 +57,7 @@
 	git add a1 &&
 	test_tick &&
 	git commit -m a1 &&
+	mkdir .git/info &&
 	umask 0277 &&
 	git update-server-info &&
 	actual="$(ls -l .git/info/refs)" &&
diff --git a/t/t1401-symbolic-ref.sh b/t/t1401-symbolic-ref.sh
index 9fb0b90..0c20408 100755
--- a/t/t1401-symbolic-ref.sh
+++ b/t/t1401-symbolic-ref.sh
@@ -165,4 +165,14 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'symbolic-ref refuses invalid target for non-HEAD' '
+	test_must_fail git symbolic-ref refs/heads/invalid foo..bar
+'
+
+test_expect_success 'symbolic-ref allows top-level target for non-HEAD' '
+	git symbolic-ref refs/heads/top-level FETCH_HEAD &&
+	git update-ref FETCH_HEAD HEAD &&
+	test_cmp_rev top-level HEAD
+'
+
 test_done
diff --git a/t/t1402-check-ref-format.sh b/t/t1402-check-ref-format.sh
index cabc516..5ed9d73 100755
--- a/t/t1402-check-ref-format.sh
+++ b/t/t1402-check-ref-format.sh
@@ -2,6 +2,7 @@
 
 test_description='Test git check-ref-format'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 valid_ref() {
diff --git a/t/t1405-main-ref-store.sh b/t/t1405-main-ref-store.sh
index 51f8291..e4627cf 100755
--- a/t/t1405-main-ref-store.sh
+++ b/t/t1405-main-ref-store.sh
@@ -5,6 +5,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 RUN="test-tool ref-store main"
diff --git a/t/t1407-worktree-ref-store.sh b/t/t1407-worktree-ref-store.sh
index ad8006c..05b1881 100755
--- a/t/t1407-worktree-ref-store.sh
+++ b/t/t1407-worktree-ref-store.sh
@@ -5,6 +5,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 RWT="test-tool ref-store worktree:wt"
diff --git a/t/t1418-reflog-exists.sh b/t/t1418-reflog-exists.sh
index d51ecd5..2268bca 100755
--- a/t/t1418-reflog-exists.sh
+++ b/t/t1418-reflog-exists.sh
@@ -4,6 +4,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t1450-fsck.sh b/t/t1450-fsck.sh
index 53c2aa1..ace4556 100755
--- a/t/t1450-fsck.sh
+++ b/t/t1450-fsck.sh
@@ -507,6 +507,54 @@
 	test_i18ngrep -q "error: hash mismatch $(dirname $new)$(test_oid ff_2)" out
 '
 
+# An actual bit corruption is more likely than swapped commits, but
+# this provides an easy way to have commits which don't match their purported
+# hashes, but which aren't so broken we can't read them at all.
+test_expect_success 'rev-list --verify-objects notices swapped commits' '
+	git init swapped-commits &&
+	(
+		cd swapped-commits &&
+		test_commit one &&
+		test_commit two &&
+		one_oid=$(git rev-parse HEAD) &&
+		two_oid=$(git rev-parse HEAD^) &&
+		one=.git/objects/$(test_oid_to_path $one_oid) &&
+		two=.git/objects/$(test_oid_to_path $two_oid) &&
+		mv $one tmp &&
+		mv $two $one &&
+		mv tmp $two &&
+		test_must_fail git rev-list --verify-objects HEAD
+	)
+'
+
+test_expect_success 'set up repository with commit-graph' '
+	git init corrupt-graph &&
+	(
+		cd corrupt-graph &&
+		test_commit one &&
+		test_commit two &&
+		git commit-graph write --reachable
+	)
+'
+
+corrupt_graph_obj () {
+	oid=$(git -C corrupt-graph rev-parse "$1") &&
+	obj=corrupt-graph/.git/objects/$(test_oid_to_path $oid) &&
+	test_when_finished 'mv backup $obj' &&
+	mv $obj backup &&
+	echo garbage >$obj
+}
+
+test_expect_success 'rev-list --verify-objects with commit graph (tip)' '
+	corrupt_graph_obj HEAD &&
+	test_must_fail git -C corrupt-graph rev-list --verify-objects HEAD
+'
+
+test_expect_success 'rev-list --verify-objects with commit graph (parent)' '
+	corrupt_graph_obj HEAD^ &&
+	test_must_fail git -C corrupt-graph rev-list --verify-objects HEAD
+'
+
 test_expect_success 'force fsck to ignore double author' '
 	git cat-file commit HEAD >basis &&
 	sed "s/^author .*/&,&/" <basis | tr , \\n >multiple-authors &&
diff --git a/t/t1500-rev-parse.sh b/t/t1500-rev-parse.sh
index 1c2df08..0e13bcb 100755
--- a/t/t1500-rev-parse.sh
+++ b/t/t1500-rev-parse.sh
@@ -4,6 +4,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_one () {
diff --git a/t/t1502-rev-parse-parseopt.sh b/t/t1502-rev-parse-parseopt.sh
index 284fe18..de1d48f 100755
--- a/t/t1502-rev-parse-parseopt.sh
+++ b/t/t1502-rev-parse-parseopt.sh
@@ -306,6 +306,13 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'test --parseopt invalid opt-spec' '
+	test_write_lines x -- "=, x" >spec &&
+	echo "fatal: missing opt-spec before option flags" >expect &&
+	test_must_fail git rev-parse --parseopt -- >out <spec 2>err &&
+	test_cmp expect err
+'
+
 test_expect_success 'test --parseopt help output: multi-line blurb after empty line' '
 	sed -e "s/^|//" >spec <<-\EOF &&
 	|cmd [--some-option]
diff --git a/t/t1503-rev-parse-verify.sh b/t/t1503-rev-parse-verify.sh
index ba43168..bc13683 100755
--- a/t/t1503-rev-parse-verify.sh
+++ b/t/t1503-rev-parse-verify.sh
@@ -132,7 +132,7 @@
 	test_must_fail git rev-parse --verify --default bar
 '
 
-test_expect_success !SANITIZE_LEAK 'main@{n} for various n' '
+test_expect_success 'main@{n} for various n' '
 	git reflog >out &&
 	N=$(wc -l <out) &&
 	Nm1=$(($N-1)) &&
diff --git a/t/t1701-racy-split-index.sh b/t/t1701-racy-split-index.sh
index 5dc221e..d8fa489 100755
--- a/t/t1701-racy-split-index.sh
+++ b/t/t1701-racy-split-index.sh
@@ -5,6 +5,7 @@
 
 test_description='racy split index'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t2006-checkout-index-basic.sh b/t/t2006-checkout-index-basic.sh
index 7705e3a..5d11987 100755
--- a/t/t2006-checkout-index-basic.sh
+++ b/t/t2006-checkout-index-basic.sh
@@ -3,6 +3,7 @@
 test_description='basic checkout-index tests
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'checkout-index --gobbledegook' '
diff --git a/t/t2018-checkout-branch.sh b/t/t2018-checkout-branch.sh
index 52e51b0..771c3c3 100755
--- a/t/t2018-checkout-branch.sh
+++ b/t/t2018-checkout-branch.sh
@@ -2,6 +2,7 @@
 
 test_description='checkout'
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 # Arguments: [!] <branch> <oid> [<checkout options>]
@@ -257,11 +258,12 @@
 		git checkout branch1-scratch &&
 		test_might_fail git branch -D branch3 &&
 		git config core.sparseCheckout false &&
-		rm .git/info/sparse-checkout" &&
+		rm -rf .git/info" &&
 
 	test_commit file2 &&
 
 	echo stuff >>file1 &&
+	mkdir .git/info &&
 	echo file2 >.git/info/sparse-checkout &&
 	git config core.sparseCheckout true &&
 
diff --git a/t/t2020-checkout-detach.sh b/t/t2020-checkout-detach.sh
index bc46713..2eab647 100755
--- a/t/t2020-checkout-detach.sh
+++ b/t/t2020-checkout-detach.sh
@@ -4,6 +4,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 check_detached () {
diff --git a/t/t2023-checkout-m.sh b/t/t2023-checkout-m.sh
index 7b327b7..81e772f 100755
--- a/t/t2023-checkout-m.sh
+++ b/t/t2023-checkout-m.sh
@@ -7,6 +7,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t2080-parallel-checkout-basics.sh b/t/t2080-parallel-checkout-basics.sh
index c683e60..00ce303 100755
--- a/t/t2080-parallel-checkout-basics.sh
+++ b/t/t2080-parallel-checkout-basics.sh
@@ -230,12 +230,9 @@
 # check the final report including sequential, parallel, and delayed entries
 # all at the same time. So we must have finer control of the parallel checkout
 # variables.
-test_expect_success PERL '"git checkout ." report should not include failed entries' '
-	write_script rot13-filter.pl "$PERL_PATH" \
-		<"$TEST_DIRECTORY"/t0021/rot13-filter.pl &&
-
+test_expect_success '"git checkout ." report should not include failed entries' '
 	test_config_global filter.delay.process \
-		"\"$(pwd)/rot13-filter.pl\" --always-delay delayed.log clean smudge delay" &&
+		"test-tool rot13-filter --always-delay --log=delayed.log clean smudge delay" &&
 	test_config_global filter.delay.required true &&
 	test_config_global filter.cat.clean cat  &&
 	test_config_global filter.cat.smudge cat  &&
diff --git a/t/t2082-parallel-checkout-attributes.sh b/t/t2082-parallel-checkout-attributes.sh
index 2525457..f3511cd 100755
--- a/t/t2082-parallel-checkout-attributes.sh
+++ b/t/t2082-parallel-checkout-attributes.sh
@@ -138,12 +138,9 @@
 # The delayed queue is independent from the parallel queue, and they should be
 # able to work together in the same checkout process.
 #
-test_expect_success PERL 'parallel-checkout and delayed checkout' '
-	write_script rot13-filter.pl "$PERL_PATH" \
-		<"$TEST_DIRECTORY"/t0021/rot13-filter.pl &&
-
+test_expect_success 'parallel-checkout and delayed checkout' '
 	test_config_global filter.delay.process \
-		"\"$(pwd)/rot13-filter.pl\" --always-delay \"$(pwd)/delayed.log\" clean smudge delay" &&
+		"test-tool rot13-filter --always-delay --log=\"$(pwd)/delayed.log\" clean smudge delay" &&
 	test_config_global filter.delay.required true &&
 
 	echo "abcd" >original &&
diff --git a/t/t2205-add-worktree-config.sh b/t/t2205-add-worktree-config.sh
index 43d950d..98265ba 100755
--- a/t/t2205-add-worktree-config.sh
+++ b/t/t2205-add-worktree-config.sh
@@ -17,6 +17,7 @@
 	   repository can be added to the index.
 	'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success '1a: setup--config worktree' '
diff --git a/t/t2400-worktree-add.sh b/t/t2400-worktree-add.sh
index 2f564d5..f3242fe 100755
--- a/t/t2400-worktree-add.sh
+++ b/t/t2400-worktree-add.sh
@@ -5,6 +5,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 . "$TEST_DIRECTORY"/lib-rebase.sh
@@ -229,6 +230,7 @@
 	SHA1=$(git rev-parse HEAD) &&
 	test_commit def &&
 	test_commit xyz &&
+	mkdir .git/info &&
 	echo "$(git rev-parse HEAD) $SHA1" >.git/info/grafts &&
 	cat >expected <<-\EOF &&
 	xyz
@@ -559,6 +561,8 @@
 '
 
 post_checkout_hook () {
+	test_when_finished "rm -rf .git/hooks" &&
+	mkdir .git/hooks &&
 	test_hook -C "$1" post-checkout <<-\EOF
 	{
 		echo $*
diff --git a/t/t2403-worktree-move.sh b/t/t2403-worktree-move.sh
index a4e1a17..1168e9f 100755
--- a/t/t2403-worktree-move.sh
+++ b/t/t2403-worktree-move.sh
@@ -2,6 +2,7 @@
 
 test_description='test git worktree move, remove, lock and unlock'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t2407-worktree-heads.sh b/t/t2407-worktree-heads.sh
new file mode 100755
index 0000000..019a40d
--- /dev/null
+++ b/t/t2407-worktree-heads.sh
@@ -0,0 +1,180 @@
+#!/bin/sh
+
+test_description='test operations trying to overwrite refs at worktree HEAD'
+
+TEST_PASSES_SANITIZE_LEAK=true
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit init &&
+
+	for i in 1 2 3 4
+	do
+		git checkout -b conflict-$i &&
+		echo "not I" >$i.t &&
+		git add $i.t &&
+		git commit -m "will conflict" &&
+
+		git checkout - &&
+		test_commit $i &&
+		git branch wt-$i &&
+		git branch fake-$i &&
+		git worktree add wt-$i wt-$i || return 1
+	done &&
+
+	# Create a server that updates each branch by one commit
+	git init server &&
+	test_commit -C server initial &&
+	git remote add server ./server &&
+	for i in 1 2 3 4
+	do
+		git -C server checkout -b wt-$i &&
+		test_commit -C server A-$i || return 1
+	done &&
+	for i in 1 2
+	do
+		git -C server checkout -b fake-$i &&
+		test_commit -C server f-$i || return 1
+	done
+'
+
+test_expect_success 'refuse to overwrite: checked out in worktree' '
+	for i in 1 2 3 4
+	do
+		test_must_fail git branch -f wt-$i HEAD 2>err &&
+		grep "cannot force update the branch" err &&
+
+		test_must_fail git branch -D wt-$i 2>err &&
+		grep "Cannot delete branch" err || return 1
+	done
+'
+
+test_expect_success !SANITIZE_LEAK 'refuse to overwrite: worktree in bisect' '
+	test_when_finished git -C wt-4 bisect reset &&
+
+	# Set up a bisect so HEAD no longer points to wt-4.
+	git -C wt-4 bisect start &&
+	git -C wt-4 bisect bad wt-4 &&
+	git -C wt-4 bisect good wt-1 &&
+
+	test_must_fail git branch -f wt-4 HEAD 2>err &&
+	grep "cannot force update the branch '\''wt-4'\'' checked out at.*wt-4" err
+'
+
+test_expect_success !SANITIZE_LEAK 'refuse to overwrite: worktree in rebase (apply)' '
+	test_when_finished git -C wt-2 rebase --abort &&
+
+	# This will fail part-way through due to a conflict.
+	test_must_fail git -C wt-2 rebase --apply conflict-2 &&
+
+	test_must_fail git branch -f wt-2 HEAD 2>err &&
+	grep "cannot force update the branch '\''wt-2'\'' checked out at.*wt-2" err
+'
+
+test_expect_success !SANITIZE_LEAK 'refuse to overwrite: worktree in rebase (merge)' '
+	test_when_finished git -C wt-2 rebase --abort &&
+
+	# This will fail part-way through due to a conflict.
+	test_must_fail git -C wt-2 rebase conflict-2 &&
+
+	test_must_fail git branch -f wt-2 HEAD 2>err &&
+	grep "cannot force update the branch '\''wt-2'\'' checked out at.*wt-2" err
+'
+
+test_expect_success !SANITIZE_LEAK 'refuse to overwrite: worktree in rebase with --update-refs' '
+	test_when_finished git -C wt-3 rebase --abort &&
+
+	git branch -f can-be-updated wt-3 &&
+	test_must_fail git -C wt-3 rebase --update-refs conflict-3 &&
+
+	for i in 3 4
+	do
+		test_must_fail git branch -f can-be-updated HEAD 2>err &&
+		grep "cannot force update the branch '\''can-be-updated'\'' checked out at.*wt-3" err ||
+			return 1
+	done
+'
+
+test_expect_success !SANITIZE_LEAK 'refuse to fetch over ref: checked out' '
+	test_must_fail git fetch server +refs/heads/wt-3:refs/heads/wt-3 2>err &&
+	grep "refusing to fetch into branch '\''refs/heads/wt-3'\''" err &&
+
+	# General fetch into refs/heads/ will fail on first ref,
+	# so use a generic error message check.
+	test_must_fail git fetch server +refs/heads/*:refs/heads/* 2>err &&
+	grep "refusing to fetch into branch" err
+'
+
+test_expect_success !SANITIZE_LEAK 'refuse to fetch over ref: worktree in bisect' '
+	test_when_finished git -C wt-4 bisect reset &&
+
+	# Set up a bisect so HEAD no longer points to wt-4.
+	git -C wt-4 bisect start &&
+	git -C wt-4 bisect bad wt-4 &&
+	git -C wt-4 bisect good wt-1 &&
+
+	test_must_fail git fetch server +refs/heads/wt-4:refs/heads/wt-4 2>err &&
+	grep "refusing to fetch into branch" err
+'
+
+test_expect_success !SANITIZE_LEAK 'refuse to fetch over ref: worktree in rebase' '
+	test_when_finished git -C wt-3 rebase --abort &&
+
+	# This will fail part-way through due to a conflict.
+	test_must_fail git -C wt-3 rebase conflict-3 &&
+
+	test_must_fail git fetch server +refs/heads/wt-3:refs/heads/wt-3 2>err &&
+	grep "refusing to fetch into branch" err
+'
+
+test_expect_success 'refuse to overwrite when in error states' '
+	test_when_finished rm -rf .git/worktrees/wt-*/rebase-merge &&
+	test_when_finished rm -rf .git/worktrees/wt-*/BISECT_* &&
+
+	# Both branches are currently under rebase.
+	mkdir -p .git/worktrees/wt-3/rebase-merge &&
+	touch .git/worktrees/wt-3/rebase-merge/interactive &&
+	echo refs/heads/fake-1 >.git/worktrees/wt-3/rebase-merge/head-name &&
+	echo refs/heads/fake-2 >.git/worktrees/wt-3/rebase-merge/onto &&
+	mkdir -p .git/worktrees/wt-4/rebase-merge &&
+	touch .git/worktrees/wt-4/rebase-merge/interactive &&
+	echo refs/heads/fake-2 >.git/worktrees/wt-4/rebase-merge/head-name &&
+	echo refs/heads/fake-1 >.git/worktrees/wt-4/rebase-merge/onto &&
+
+	# Both branches are currently under bisect.
+	touch .git/worktrees/wt-4/BISECT_LOG &&
+	echo refs/heads/fake-2 >.git/worktrees/wt-4/BISECT_START &&
+	touch .git/worktrees/wt-1/BISECT_LOG &&
+	echo refs/heads/fake-1 >.git/worktrees/wt-1/BISECT_START &&
+
+	for i in 1 2
+	do
+		test_must_fail git branch -f fake-$i HEAD 2>err &&
+		grep "cannot force update the branch '\''fake-$i'\'' checked out at" err ||
+			return 1
+	done
+'
+
+. "$TEST_DIRECTORY"/lib-rebase.sh
+
+test_expect_success !SANITIZE_LEAK 'refuse to overwrite during rebase with --update-refs' '
+	git commit --fixup HEAD~2 --allow-empty &&
+	(
+		set_cat_todo_editor &&
+		test_must_fail git rebase -i --update-refs HEAD~3 >todo &&
+		! grep "update-refs" todo
+	) &&
+	git branch -f allow-update HEAD~2 &&
+	(
+		set_cat_todo_editor &&
+		test_must_fail git rebase -i --update-refs HEAD~3 >todo &&
+		grep "update-ref refs/heads/allow-update" todo
+	)
+'
+
+# This must be the last test in this file
+test_expect_success '$EDITOR and friends are unchanged' '
+	test_editor_unchanged
+'
+
+test_done
diff --git a/t/t3001-ls-files-others-exclude.sh b/t/t3001-ls-files-others-exclude.sh
index e07ac6c..1ed0aa9 100755
--- a/t/t3001-ls-files-others-exclude.sh
+++ b/t/t3001-ls-files-others-exclude.sh
@@ -103,7 +103,7 @@
 	test_cmp expect output
 '
 
-test_expect_success !SANITIZE_LEAK 'restore gitignore' '
+test_expect_success 'restore gitignore' '
 	git checkout --ignore-skip-worktree-bits $allignores &&
 	rm .git/index
 '
@@ -126,7 +126,7 @@
 #	three/
 EOF
 
-test_expect_success !SANITIZE_LEAK 'git status honors core.excludesfile' \
+test_expect_success 'git status honors core.excludesfile' \
 	'test_cmp expect output'
 
 test_expect_success 'trailing slash in exclude allows directory match(1)' '
diff --git a/t/t3012-ls-files-dedup.sh b/t/t3012-ls-files-dedup.sh
index 2682b1f..190e2f6 100755
--- a/t/t3012-ls-files-dedup.sh
+++ b/t/t3012-ls-files-dedup.sh
@@ -2,6 +2,7 @@
 
 test_description='git ls-files --deduplicate test'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t3013-ls-files-format.sh b/t/t3013-ls-files-format.sh
new file mode 100755
index 0000000..efb7450
--- /dev/null
+++ b/t/t3013-ls-files-format.sh
@@ -0,0 +1,95 @@
+#!/bin/sh
+
+test_description='git ls-files --format test'
+
+TEST_PASSES_SANITIZE_LEAK=true
+. ./test-lib.sh
+
+for flag in -s -o -k -t --resolve-undo --deduplicate --eol
+do
+	test_expect_success "usage: --format is incompatible with $flag" '
+		test_expect_code 129 git ls-files --format="%(objectname)" $flag
+	'
+done
+
+test_expect_success 'setup' '
+	printf "LINEONE\nLINETWO\nLINETHREE\n" >o1.txt &&
+	printf "LINEONE\r\nLINETWO\r\nLINETHREE\r\n" >o2.txt &&
+	printf "LINEONE\r\nLINETWO\nLINETHREE\n" >o3.txt &&
+	git add o?.txt &&
+	oid=$(git hash-object o1.txt) &&
+	git update-index --add --cacheinfo 120000 $oid o4.txt &&
+	git update-index --add --cacheinfo 160000 $oid o5.txt &&
+	git update-index --add --cacheinfo 100755 $oid o6.txt &&
+	git commit -m base
+'
+
+test_expect_success 'git ls-files --format objectmode v.s. -s' '
+	git ls-files -s >files &&
+	cut -d" " -f1 files >expect &&
+	git ls-files --format="%(objectmode)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files --format objectname v.s. -s' '
+	git ls-files -s >files &&
+	cut -d" " -f2 files >expect &&
+	git ls-files --format="%(objectname)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files --format v.s. --eol' '
+	git ls-files --eol >tmp &&
+	sed -e "s/	/ /g" -e "s/  */ /g" tmp >expect 2>err &&
+	test_must_be_empty err &&
+	git ls-files --format="i/%(eolinfo:index) w/%(eolinfo:worktree) attr/%(eolattr) %(path)" >actual 2>err &&
+	test_must_be_empty err &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files --format path v.s. -s' '
+	git ls-files -s >files &&
+	cut -f2 files >expect &&
+	git ls-files --format="%(path)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files --format with -m' '
+	echo change >o1.txt &&
+	cat >expect <<-\EOF &&
+	o1.txt
+	o4.txt
+	o5.txt
+	o6.txt
+	EOF
+	git ls-files --format="%(path)" -m >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files --format with -d' '
+	echo o7 >o7.txt &&
+	git add o7.txt &&
+	rm o7.txt &&
+	cat >expect <<-\EOF &&
+	o4.txt
+	o5.txt
+	o6.txt
+	o7.txt
+	EOF
+	git ls-files --format="%(path)" -d >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files --format v.s -s' '
+	git ls-files --stage >expect &&
+	git ls-files --format="%(objectmode) %(objectname) %(stage)%x09%(path)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git ls-files --format with --debug' '
+	git ls-files --debug >expect &&
+	git ls-files --format="%(path)" --debug >actual &&
+	test_cmp expect actual
+'
+
+test_done
diff --git a/t/t3206-range-diff.sh b/t/t3206-range-diff.sh
index d12e4e4..459beaf 100755
--- a/t/t3206-range-diff.sh
+++ b/t/t3206-range-diff.sh
@@ -162,7 +162,7 @@
 '
 
 test_expect_success 'A^{/..} is not mistaken for a range' '
-	test_must_fail git range-diff topic^.. topic^{/..} 2>error &&
+	test_must_fail git range-diff topic^.. topic^{/..} -- 2>error &&
 	test_i18ngrep "not a commit range" error
 '
 
@@ -772,6 +772,17 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'ranges with pathspecs' '
+	git range-diff topic...mode-only-change -- other-file >actual &&
+	test_line_count = 2 actual &&
+	topic_oid=$(git rev-parse --short topic) &&
+	mode_change_oid=$(git rev-parse --short mode-only-change^) &&
+	file_change_oid=$(git rev-parse --short mode-only-change) &&
+	grep "$mode_change_oid" actual &&
+	! grep "$file_change_oid" actual &&
+	! grep "$topic_oid" actual
+'
+
 test_expect_success 'submodule changes are shown irrespective of diff.submodule' '
 	git init sub-repo &&
 	test_commit -C sub-repo sub-first &&
diff --git a/t/t3301-notes.sh b/t/t3301-notes.sh
index d742be8..3288aae 100755
--- a/t/t3301-notes.sh
+++ b/t/t3301-notes.sh
@@ -505,6 +505,11 @@
 	test_cmp expect actual
 '
 
+test_expect_success '"git notes" without subcommand does not take arguments' '
+	test_expect_code 129 git notes HEAD^^ 2>err &&
+	grep "^error: unknown subcommand" err
+'
+
 test_expect_success 'list specific note with "git notes list <object>"' '
 	git rev-parse refs/notes/commits:$commit_3 >expect &&
 	git notes list HEAD^^ >actual &&
diff --git a/t/t3304-notes-mixed.sh b/t/t3304-notes-mixed.sh
index 03dfcd3..2c3a245 100755
--- a/t/t3304-notes-mixed.sh
+++ b/t/t3304-notes-mixed.sh
@@ -5,6 +5,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 number_of_commits=100
diff --git a/t/t3305-notes-fanout.sh b/t/t3305-notes-fanout.sh
index 64a9915..22ffe5b 100755
--- a/t/t3305-notes-fanout.sh
+++ b/t/t3305-notes-fanout.sh
@@ -51,7 +51,7 @@
 	done
 '
 
-test_expect_success !SANITIZE_LEAK 'many notes created correctly with git-notes' '
+test_expect_success 'many notes created correctly with git-notes' '
 	git log >output.raw &&
 	grep "^    " output.raw >output &&
 	i=$num_notes &&
diff --git a/t/t3307-notes-man.sh b/t/t3307-notes-man.sh
index 1aa366a..ae31650 100755
--- a/t/t3307-notes-man.sh
+++ b/t/t3307-notes-man.sh
@@ -4,6 +4,7 @@
 
 Make sure the manual is not full of lies.'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index f31afd4..688b01e 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -1743,6 +1743,279 @@
 	test_cmp_rev ORIG_HEAD test-orig-head@{1}
 '
 
+test_expect_success '--update-refs adds label and update-ref commands' '
+	git checkout -b update-refs no-conflict-branch &&
+	git branch -f base HEAD~4 &&
+	git branch -f first HEAD~3 &&
+	git branch -f second HEAD~3 &&
+	git branch -f third HEAD~1 &&
+	git commit --allow-empty --fixup=third &&
+	git branch -f is-not-reordered &&
+	git commit --allow-empty --fixup=HEAD~4 &&
+	git branch -f shared-tip &&
+	(
+		set_cat_todo_editor &&
+
+		cat >expect <<-EOF &&
+		pick $(git log -1 --format=%h J) J
+		fixup $(git log -1 --format=%h update-refs) fixup! J # empty
+		update-ref refs/heads/second
+		update-ref refs/heads/first
+		pick $(git log -1 --format=%h K) K
+		pick $(git log -1 --format=%h L) L
+		fixup $(git log -1 --format=%h is-not-reordered) fixup! L # empty
+		update-ref refs/heads/third
+		pick $(git log -1 --format=%h M) M
+		update-ref refs/heads/no-conflict-branch
+		update-ref refs/heads/is-not-reordered
+		update-ref refs/heads/shared-tip
+		EOF
+
+		test_must_fail git rebase -i --autosquash --update-refs primary >todo &&
+		test_cmp expect todo &&
+
+		test_must_fail git -c rebase.autosquash=true \
+				   -c rebase.updaterefs=true \
+				   rebase -i primary >todo &&
+
+		test_cmp expect todo
+	)
+'
+
+test_expect_success '--update-refs adds commands with --rebase-merges' '
+	git checkout -b update-refs-with-merge no-conflict-branch &&
+	git branch -f base HEAD~4 &&
+	git branch -f first HEAD~3 &&
+	git branch -f second HEAD~3 &&
+	git branch -f third HEAD~1 &&
+	git merge -m merge branch2 &&
+	git branch -f merge-branch &&
+	git commit --fixup=third --allow-empty &&
+	(
+		set_cat_todo_editor &&
+
+		cat >expect <<-EOF &&
+		label onto
+		reset onto
+		pick $(git log -1 --format=%h branch2~1) F
+		pick $(git log -1 --format=%h branch2) I
+		update-ref refs/heads/branch2
+		label merge
+		reset onto
+		pick $(git log -1 --format=%h refs/heads/second) J
+		update-ref refs/heads/second
+		update-ref refs/heads/first
+		pick $(git log -1 --format=%h refs/heads/third~1) K
+		pick $(git log -1 --format=%h refs/heads/third) L
+		fixup $(git log -1 --format=%h update-refs-with-merge) fixup! L # empty
+		update-ref refs/heads/third
+		pick $(git log -1 --format=%h HEAD~2) M
+		update-ref refs/heads/no-conflict-branch
+		merge -C $(git log -1 --format=%h HEAD~1) merge # merge
+		update-ref refs/heads/merge-branch
+		EOF
+
+		test_must_fail git rebase -i --autosquash \
+				   --rebase-merges=rebase-cousins \
+				   --update-refs primary >todo &&
+
+		test_cmp expect todo &&
+
+		test_must_fail git -c rebase.autosquash=true \
+				   -c rebase.updaterefs=true \
+				   rebase -i \
+				   --rebase-merges=rebase-cousins \
+				   primary >todo &&
+
+		test_cmp expect todo
+	)
+'
+
+test_expect_success '--update-refs updates refs correctly' '
+	git checkout -B update-refs no-conflict-branch &&
+	git branch -f base HEAD~4 &&
+	git branch -f first HEAD~3 &&
+	git branch -f second HEAD~3 &&
+	git branch -f third HEAD~1 &&
+	test_commit extra2 fileX &&
+	git commit --amend --fixup=L &&
+
+	git rebase -i --autosquash --update-refs primary 2>err &&
+
+	test_cmp_rev HEAD~3 refs/heads/first &&
+	test_cmp_rev HEAD~3 refs/heads/second &&
+	test_cmp_rev HEAD~1 refs/heads/third &&
+	test_cmp_rev HEAD refs/heads/no-conflict-branch &&
+
+	cat >expect <<-\EOF &&
+	Successfully rebased and updated refs/heads/update-refs.
+	Updated the following refs with --update-refs:
+		refs/heads/first
+		refs/heads/no-conflict-branch
+		refs/heads/second
+		refs/heads/third
+	EOF
+
+	# Clear "Rebasing (X/Y)" progress lines and drop leading tabs.
+	sed -e "s/Rebasing.*Successfully/Successfully/g" -e "s/^\t//g" \
+		<err >err.trimmed &&
+	test_cmp expect err.trimmed
+'
+
+test_expect_success 'respect user edits to update-ref steps' '
+	git checkout -B update-refs-break no-conflict-branch &&
+	git branch -f base HEAD~4 &&
+	git branch -f first HEAD~3 &&
+	git branch -f second HEAD~3 &&
+	git branch -f third HEAD~1 &&
+	git branch -f unseen base &&
+
+	# First, we will add breaks to the expected todo file
+	cat >fake-todo-1 <<-EOF &&
+	pick $(git rev-parse HEAD~3)
+	break
+	update-ref refs/heads/second
+	update-ref refs/heads/first
+
+	pick $(git rev-parse HEAD~2)
+	pick $(git rev-parse HEAD~1)
+	update-ref refs/heads/third
+
+	pick $(git rev-parse HEAD)
+	update-ref refs/heads/no-conflict-branch
+	EOF
+
+	# Second, we will drop some update-refs commands (and move one)
+	cat >fake-todo-2 <<-EOF &&
+	update-ref refs/heads/second
+
+	pick $(git rev-parse HEAD~2)
+	update-ref refs/heads/third
+	pick $(git rev-parse HEAD~1)
+	break
+
+	pick $(git rev-parse HEAD)
+	EOF
+
+	# Third, we will:
+	# * insert a new one (new-branch),
+	# * re-add an old one (first), and
+	# * add a second instance of a previously-stored one (second)
+	cat >fake-todo-3 <<-EOF &&
+	update-ref refs/heads/unseen
+	update-ref refs/heads/new-branch
+	pick $(git rev-parse HEAD)
+	update-ref refs/heads/first
+	update-ref refs/heads/second
+	EOF
+
+	(
+		set_replace_editor fake-todo-1 &&
+		git rebase -i --update-refs primary &&
+
+		# These branches are currently locked.
+		for b in first second third no-conflict-branch
+		do
+			test_must_fail git branch -f $b base || return 1
+		done &&
+
+		set_replace_editor fake-todo-2 &&
+		git rebase --edit-todo &&
+
+		# These branches are currently locked.
+		for b in second third
+		do
+			test_must_fail git branch -f $b base || return 1
+		done &&
+
+		# These branches are currently unlocked for checkout.
+		for b in first no-conflict-branch
+		do
+			git worktree add wt-$b $b &&
+			git worktree remove wt-$b || return 1
+		done &&
+
+		git rebase --continue &&
+
+		set_replace_editor fake-todo-3 &&
+		git rebase --edit-todo &&
+
+		# These branches are currently locked.
+		for b in second third first unseen
+		do
+			test_must_fail git branch -f $b base || return 1
+		done &&
+
+		# These branches are currently unlocked for checkout.
+		for b in no-conflict-branch
+		do
+			git worktree add wt-$b $b &&
+			git worktree remove wt-$b || return 1
+		done &&
+
+		git rebase --continue
+	) &&
+
+	test_cmp_rev HEAD~2 refs/heads/third &&
+	test_cmp_rev HEAD~1 refs/heads/unseen &&
+	test_cmp_rev HEAD~1 refs/heads/new-branch &&
+	test_cmp_rev HEAD refs/heads/first &&
+	test_cmp_rev HEAD refs/heads/second &&
+	test_cmp_rev HEAD refs/heads/no-conflict-branch
+'
+
+test_expect_success '--update-refs: check failed ref update' '
+	git checkout -B update-refs-error no-conflict-branch &&
+	git branch -f base HEAD~4 &&
+	git branch -f first HEAD~3 &&
+	git branch -f second HEAD~2 &&
+	git branch -f third HEAD~1 &&
+
+	cat >fake-todo <<-EOF &&
+	pick $(git rev-parse HEAD~3)
+	break
+	update-ref refs/heads/first
+
+	pick $(git rev-parse HEAD~2)
+	update-ref refs/heads/second
+
+	pick $(git rev-parse HEAD~1)
+	update-ref refs/heads/third
+
+	pick $(git rev-parse HEAD)
+	update-ref refs/heads/no-conflict-branch
+	EOF
+
+	(
+		set_replace_editor fake-todo &&
+		git rebase -i --update-refs base
+	) &&
+
+	# At this point, the values of first, second, and third are
+	# recorded in the update-refs file. We will force-update the
+	# "second" ref, but "git branch -f" will not work because of
+	# the lock in the update-refs file.
+	git rev-parse third >.git/refs/heads/second &&
+
+	test_must_fail git rebase --continue 2>err &&
+	grep "update_ref failed for ref '\''refs/heads/second'\''" err &&
+
+	cat >expect <<-\EOF &&
+	Updated the following refs with --update-refs:
+		refs/heads/first
+		refs/heads/no-conflict-branch
+		refs/heads/third
+	Failed to update the following refs with --update-refs:
+		refs/heads/second
+	EOF
+
+	# Clear "Rebasing (X/Y)" progress lines and drop leading tabs.
+	tail -n 6 err >err.last &&
+	sed -e "s/Rebasing.*Successfully/Successfully/g" -e "s/^\t//g" \
+		<err.last >err.trimmed &&
+	test_cmp expect err.trimmed
+'
+
 # This must be the last test in this file
 test_expect_success '$EDITOR and friends are unchanged' '
 	test_editor_unchanged
diff --git a/t/t3426-rebase-submodule.sh b/t/t3426-rebase-submodule.sh
index 0ad3a07..7a9f112 100755
--- a/t/t3426-rebase-submodule.sh
+++ b/t/t3426-rebase-submodule.sh
@@ -35,6 +35,7 @@
 	ls -1pR * >>actual &&
 	test_cmp expect actual &&
 	set_fake_editor &&
+	mkdir .git/info &&
 	echo "fake-editor.sh" >.git/info/exclude &&
 	may_only_be_test_must_fail "$2" &&
 	$2 git rebase -i "$1"
diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
index 979e843..f32799e 100755
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -12,6 +12,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 pristine_detach () {
@@ -558,6 +559,7 @@
 		echo \"/*\" >.git/info/sparse-checkout
 		git read-tree --reset -u HEAD
 		rm .git/info/sparse-checkout" &&
+	mkdir .git/info &&
 	echo /unrelated >.git/info/sparse-checkout &&
 	git read-tree --reset -u HEAD &&
 	test_must_fail git cherry-pick -Xours picked>actual &&
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index b354fb3..5841f28 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -7,9 +7,9 @@
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-terminal.sh
 
-if ! test_have_prereq PERL
+if test_have_prereq !ADD_I_USE_BUILTIN,!PERL
 then
-	skip_all='skipping add -i tests, perl not available'
+	skip_all='skipping add -i (scripted) tests, perl not available'
 	test_done
 fi
 
@@ -761,9 +761,33 @@
 	git reset --hard &&
 
 	echo content >test &&
-	test_config interactive.diffFilter "sed 1d" &&
+	test_config interactive.diffFilter "sed 6d" &&
 	printf y >y &&
-	force_color test_must_fail git add -p <y
+	force_color test_must_fail git add -p <y >output 2>&1 &&
+	grep "mismatched output" output
+'
+
+test_expect_success 'handle iffy colored hunk headers' '
+	git reset --hard &&
+
+	echo content >test &&
+	printf n >n &&
+	force_color git -c interactive.diffFilter="sed s/.*@@.*/XX/" \
+		add -p >output 2>&1 <n &&
+	grep "^XX$" output
+'
+
+test_expect_success 'handle very large filtered diff' '
+	git reset --hard &&
+	# The specific number here is not important, but it must
+	# be large enough that the output of "git diff --color"
+	# fills up the pipe buffer. 10,000 results in ~200k of
+	# colored output.
+	test_seq 10000 >test &&
+	test_config interactive.diffFilter cat &&
+	printf y >y &&
+	force_color git add -p >output 2>&1 <y &&
+	git diff-files --exit-code -- test
 '
 
 test_expect_success 'diff.algorithm is passed to `git diff-files`' '
@@ -931,6 +955,18 @@
 	! grep dirty-otherwise output
 '
 
+test_expect_success 'handle submodules' '
+	echo 123 >>for-submodules/dirty-otherwise/initial.t &&
+
+	force_color git -C for-submodules add -p dirty-otherwise >output 2>&1 &&
+	grep "No changes" output &&
+
+	force_color git -C for-submodules add -p dirty-head >output 2>&1 <y &&
+	git -C for-submodules ls-files --stage dirty-head >actual &&
+	rev="$(git -C for-submodules/dirty-head rev-parse HEAD)" &&
+	grep "$rev" actual
+'
+
 test_expect_success 'set up pathological context' '
 	git reset --hard &&
 	test_write_lines a a a a a a a a a a a >a &&
diff --git a/t/t3903-stash.sh b/t/t3903-stash.sh
index 2a4c3fd..376cc8f 100755
--- a/t/t3903-stash.sh
+++ b/t/t3903-stash.sh
@@ -25,7 +25,7 @@
 	grep -F "or: git stash show" usage
 '
 
-test_expect_failure 'usage for subcommands should emit subcommand usage' '
+test_expect_success 'usage for subcommands should emit subcommand usage' '
 	test_expect_code 129 git stash push -h >usage &&
 	grep -F "usage: git stash [push" usage
 '
diff --git a/t/t3920-crlf-messages.sh b/t/t3920-crlf-messages.sh
index 0276edb..4c661d4 100755
--- a/t/t3920-crlf-messages.sh
+++ b/t/t3920-crlf-messages.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='Test ref-filter and pretty APIs for commit and tag messages using CRLF'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 LIB_CRLF_BRANCHES=""
diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index 056e922..dfcf3a0 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -352,6 +352,8 @@
 log -IA -IB -I1 -I2 -p master
 log --decorate --all
 log --decorate=full --all
+log --decorate --clear-decorations --all
+log --decorate=full --clear-decorations --all
 
 rev-list --parents HEAD
 rev-list --children HEAD
diff --git a/t/t4013/diff.log_--decorate=full_--all b/t/t4013/diff.log_--decorate=full_--all
index 3f9b872..6b0b334 100644
--- a/t/t4013/diff.log_--decorate=full_--all
+++ b/t/t4013/diff.log_--decorate=full_--all
@@ -20,7 +20,7 @@
 
     Rearranged lines in dir/sub
 
-commit cbacedd14cb8b89255a2c02b59e77a2e9a8021a0 (refs/notes/commits)
+commit cbacedd14cb8b89255a2c02b59e77a2e9a8021a0
 Author: A U Thor <author@example.com>
 Date:   Mon Jun 26 00:06:00 2006 +0000
 
diff --git a/t/t4013/diff.log_--decorate=full_--clear-decorations_--all b/t/t4013/diff.log_--decorate=full_--clear-decorations_--all
new file mode 100644
index 0000000..1c030a6
--- /dev/null
+++ b/t/t4013/diff.log_--decorate=full_--clear-decorations_--all
@@ -0,0 +1,61 @@
+$ git log --decorate=full --clear-decorations --all
+commit b7e0bc69303b488b47deca799a7d723971dfa6cd (refs/heads/mode)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    update mode
+
+commit a6f364368ca320bc5a92e18912e16fa6b3dff598 (refs/heads/note)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    update mode (file2)
+
+Notes:
+    note
+
+commit cd4e72fd96faed3f0ba949dc42967430374e2290 (refs/heads/rearrange)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    Rearranged lines in dir/sub
+
+commit cbacedd14cb8b89255a2c02b59e77a2e9a8021a0 (refs/notes/commits)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    Notes added by 'git notes add'
+
+commit 59d314ad6f356dd08601a4cd5e530381da3e3c64 (HEAD -> refs/heads/master)
+Merge: 9a6d494 c7a2ab9
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:04:00 2006 +0000
+
+    Merge branch 'side'
+
+commit c7a2ab9e8eac7b117442a607d5a9b3950ae34d5a (refs/heads/side)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:03:00 2006 +0000
+
+    Side
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a (refs/heads/initial)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+$
diff --git a/t/t4013/diff.log_--decorate=full_--decorate-all_--all b/t/t4013/diff.log_--decorate=full_--decorate-all_--all
new file mode 100644
index 0000000..d6e7928
--- /dev/null
+++ b/t/t4013/diff.log_--decorate=full_--decorate-all_--all
@@ -0,0 +1,61 @@
+$ git log --decorate=full --decorate-all --all
+commit b7e0bc69303b488b47deca799a7d723971dfa6cd (refs/heads/mode)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    update mode
+
+commit a6f364368ca320bc5a92e18912e16fa6b3dff598 (refs/heads/note)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    update mode (file2)
+
+Notes:
+    note
+
+commit cd4e72fd96faed3f0ba949dc42967430374e2290 (refs/heads/rearrange)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    Rearranged lines in dir/sub
+
+commit cbacedd14cb8b89255a2c02b59e77a2e9a8021a0 (refs/notes/commits)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    Notes added by 'git notes add'
+
+commit 59d314ad6f356dd08601a4cd5e530381da3e3c64 (HEAD -> refs/heads/master)
+Merge: 9a6d494 c7a2ab9
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:04:00 2006 +0000
+
+    Merge branch 'side'
+
+commit c7a2ab9e8eac7b117442a607d5a9b3950ae34d5a (refs/heads/side)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:03:00 2006 +0000
+
+    Side
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a (refs/heads/initial)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+$
diff --git a/t/t4013/diff.log_--decorate_--all b/t/t4013/diff.log_--decorate_--all
index f5e20e1..c7df1f5 100644
--- a/t/t4013/diff.log_--decorate_--all
+++ b/t/t4013/diff.log_--decorate_--all
@@ -20,7 +20,7 @@
 
     Rearranged lines in dir/sub
 
-commit cbacedd14cb8b89255a2c02b59e77a2e9a8021a0 (refs/notes/commits)
+commit cbacedd14cb8b89255a2c02b59e77a2e9a8021a0
 Author: A U Thor <author@example.com>
 Date:   Mon Jun 26 00:06:00 2006 +0000
 
diff --git a/t/t4013/diff.log_--decorate_--clear-decorations_--all b/t/t4013/diff.log_--decorate_--clear-decorations_--all
new file mode 100644
index 0000000..88be82c
--- /dev/null
+++ b/t/t4013/diff.log_--decorate_--clear-decorations_--all
@@ -0,0 +1,61 @@
+$ git log --decorate --clear-decorations --all
+commit b7e0bc69303b488b47deca799a7d723971dfa6cd (mode)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    update mode
+
+commit a6f364368ca320bc5a92e18912e16fa6b3dff598 (note)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    update mode (file2)
+
+Notes:
+    note
+
+commit cd4e72fd96faed3f0ba949dc42967430374e2290 (rearrange)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    Rearranged lines in dir/sub
+
+commit cbacedd14cb8b89255a2c02b59e77a2e9a8021a0 (refs/notes/commits)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    Notes added by 'git notes add'
+
+commit 59d314ad6f356dd08601a4cd5e530381da3e3c64 (HEAD -> master)
+Merge: 9a6d494 c7a2ab9
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:04:00 2006 +0000
+
+    Merge branch 'side'
+
+commit c7a2ab9e8eac7b117442a607d5a9b3950ae34d5a (side)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:03:00 2006 +0000
+
+    Side
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a (initial)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+$
diff --git a/t/t4013/diff.log_--decorate_--decorate-all_--all b/t/t4013/diff.log_--decorate_--decorate-all_--all
new file mode 100644
index 0000000..5d22618
--- /dev/null
+++ b/t/t4013/diff.log_--decorate_--decorate-all_--all
@@ -0,0 +1,61 @@
+$ git log --decorate --decorate-all --all
+commit b7e0bc69303b488b47deca799a7d723971dfa6cd (mode)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    update mode
+
+commit a6f364368ca320bc5a92e18912e16fa6b3dff598 (note)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    update mode (file2)
+
+Notes:
+    note
+
+commit cd4e72fd96faed3f0ba949dc42967430374e2290 (rearrange)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    Rearranged lines in dir/sub
+
+commit cbacedd14cb8b89255a2c02b59e77a2e9a8021a0 (refs/notes/commits)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:06:00 2006 +0000
+
+    Notes added by 'git notes add'
+
+commit 59d314ad6f356dd08601a4cd5e530381da3e3c64 (HEAD -> master)
+Merge: 9a6d494 c7a2ab9
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:04:00 2006 +0000
+
+    Merge branch 'side'
+
+commit c7a2ab9e8eac7b117442a607d5a9b3950ae34d5a (side)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:03:00 2006 +0000
+
+    Side
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a (initial)
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+$
diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index fbec8ad..ad5c029 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -1400,6 +1400,43 @@
 	test_cmp expect patch.head
 '
 
+test_expect_success 'with --force-in-body-from, redundant in-body from is kept' '
+	git format-patch --force-in-body-from \
+		-1 --stdout --from="A U Thor <author@example.com>" >patch &&
+	cat >expect <<-\EOF &&
+	From: A U Thor <author@example.com>
+
+	From: A U Thor <author@example.com>
+
+	EOF
+	sed -ne "/^From:/p; /^$/p; /^---$/q" patch >patch.head &&
+	test_cmp expect patch.head
+'
+
+test_expect_success 'format.forceInBodyFrom, equivalent to --force-in-body-from' '
+	git -c format.forceInBodyFrom=yes format-patch \
+		-1 --stdout --from="A U Thor <author@example.com>" >patch &&
+	cat >expect <<-\EOF &&
+	From: A U Thor <author@example.com>
+
+	From: A U Thor <author@example.com>
+
+	EOF
+	sed -ne "/^From:/p; /^$/p; /^---$/q" patch >patch.head &&
+	test_cmp expect patch.head
+'
+
+test_expect_success 'format.forceInBodyFrom, equivalent to --force-in-body-from' '
+	git -c format.forceInBodyFrom=yes format-patch --no-force-in-body-from \
+		-1 --stdout --from="A U Thor <author@example.com>" >patch &&
+	cat >expect <<-\EOF &&
+	From: A U Thor <author@example.com>
+
+	EOF
+	sed -ne "/^From:/p; /^$/p; /^---$/q" patch >patch.head &&
+	test_cmp expect patch.head
+'
+
 test_expect_success 'in-body headers trigger content encoding' '
 	test_env GIT_AUTHOR_NAME="éxötìc" test_commit exotic &&
 	test_when_finished "git reset --hard HEAD^" &&
diff --git a/t/t4017-diff-retval.sh b/t/t4017-diff-retval.sh
index ed461f4..5bc28ad 100755
--- a/t/t4017-diff-retval.sh
+++ b/t/t4017-diff-retval.sh
@@ -5,6 +5,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t4020-diff-external.sh b/t/t4020-diff-external.sh
index 858a552..c1ac09e 100755
--- a/t/t4020-diff-external.sh
+++ b/t/t4020-diff-external.sh
@@ -33,7 +33,7 @@
 
 '
 
-test_expect_success !SANITIZE_LEAK 'GIT_EXTERNAL_DIFF environment should apply only to diff' '
+test_expect_success 'GIT_EXTERNAL_DIFF environment should apply only to diff' '
 	GIT_EXTERNAL_DIFF=echo git log -p -1 HEAD >out &&
 	grep "^diff --git a/file b/file" out
 
@@ -74,7 +74,7 @@
 	test_cmp expect actual
 '
 
-test_expect_success !SANITIZE_LEAK 'diff.external should apply only to diff' '
+test_expect_success 'diff.external should apply only to diff' '
 	test_config diff.external echo &&
 	git log -p -1 HEAD >out &&
 	grep "^diff --git a/file b/file" out
diff --git a/t/t4044-diff-index-unique-abbrev.sh b/t/t4044-diff-index-unique-abbrev.sh
index 4701796..29e49d2 100755
--- a/t/t4044-diff-index-unique-abbrev.sh
+++ b/t/t4044-diff-index-unique-abbrev.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test unique sha1 abbreviation on "index from..to" line'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t4051-diff-function-context.sh b/t/t4051-diff-function-context.sh
index 4838a1d..725278a 100755
--- a/t/t4051-diff-function-context.sh
+++ b/t/t4051-diff-function-context.sh
@@ -2,6 +2,7 @@
 
 test_description='diff function context'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 dir="$TEST_DIRECTORY/t4051"
diff --git a/t/t4057-diff-combined-paths.sh b/t/t4057-diff-combined-paths.sh
index 04b8a15..9a7505c 100755
--- a/t/t4057-diff-combined-paths.sh
+++ b/t/t4057-diff-combined-paths.sh
@@ -5,6 +5,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # verify that diffc.expect matches output of
diff --git a/t/t4069-remerge-diff.sh b/t/t4069-remerge-diff.sh
index 35f9495..07323eb 100755
--- a/t/t4069-remerge-diff.sh
+++ b/t/t4069-remerge-diff.sh
@@ -56,6 +56,11 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'remerge-diff on a clean merge with a filter' '
+	git show --oneline --remerge-diff --diff-filter=U bc_resolution >actual &&
+	test_must_be_empty actual
+'
+
 test_expect_success 'remerge-diff with both a resolved conflict and an unrelated change' '
 	git log -1 --oneline ab_resolution >tmp &&
 	cat <<-EOF >>tmp &&
@@ -89,6 +94,22 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'pickaxe still includes additional headers for relevant changes' '
+	# reuses "expect" from the previous testcase
+
+	git log --oneline --remerge-diff -Sacht ab_resolution >tmp &&
+	sed -e "s/[0-9a-f]\{7,\}/HASH/g" tmp >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'can filter out additional headers with pickaxe' '
+	git show --remerge-diff --submodule=log --find-object=HEAD ab_resolution >actual &&
+	test_must_be_empty actual &&
+
+	git show --remerge-diff -S"not present" --all >actual &&
+	test_must_be_empty actual
+'
+
 test_expect_success 'setup non-content conflicts' '
 	git switch --orphan base &&
 
@@ -184,6 +205,14 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'submodule formatting ignores additional headers' '
+	# Reuses "expect" from last testcase
+
+	git show --oneline --remerge-diff --diff-filter=U --submodule=log >tmp &&
+	sed -e "s/[0-9a-f]\{7,\}/HASH/g" tmp >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'remerge-diff w/ diff-filter=R: relevant file + conflict header' '
 	git log -1 --oneline resolution >tmp &&
 	cat <<-EOF >>tmp &&
diff --git a/t/t4114-apply-typechange.sh b/t/t4114-apply-typechange.sh
index da3e64f..8ff3640 100755
--- a/t/t4114-apply-typechange.sh
+++ b/t/t4114-apply-typechange.sh
@@ -7,6 +7,7 @@
 
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup repository and commits' '
diff --git a/t/t4140-apply-ita.sh b/t/t4140-apply-ita.sh
index c614eaf..b375aca 100755
--- a/t/t4140-apply-ita.sh
+++ b/t/t4140-apply-ita.sh
@@ -2,6 +2,7 @@
 
 test_description='git apply of i-t-a file'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 6e66352..cc15cb4 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -704,9 +704,12 @@
 	git checkout -b tangle HEAD~6 &&
 	test_commit tangle-a tangle-a a &&
 	git merge main~3 &&
+	git update-ref refs/prefetch/merge HEAD &&
 	git merge side~1 &&
+	git update-ref refs/rewritten/merge HEAD &&
 	git checkout main &&
 	git merge tangle &&
+	git update-ref refs/hidden/tangle HEAD &&
 	git checkout -b reach &&
 	test_commit reach &&
 	git checkout main &&
@@ -974,9 +977,9 @@
 	Merge-tag-reach (HEAD -> main)
 	reach (tag: reach, reach)
 	seventh (tag: seventh)
-	Merge-branch-tangle
-	Merge-branch-side-early-part-into-tangle (tangle)
-	tangle-a (tag: tangle-a)
+	Merge-branch-tangle (refs/hidden/tangle)
+	Merge-branch-side-early-part-into-tangle (refs/rewritten/merge, tangle)
+	Merge-branch-main-early-part-into-tangle (refs/prefetch/merge)
 	EOF
 	git log -n6 --decorate=short --pretty="tformat:%f%d" \
 		--decorate-refs-exclude="*octopus*" \
@@ -1025,6 +1028,115 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'decorate-refs-exclude HEAD' '
+	git log --decorate=full --oneline \
+		--decorate-refs-exclude="HEAD" >actual &&
+	! grep HEAD actual
+'
+
+test_expect_success 'decorate-refs focus from default' '
+	git log --decorate=full --oneline \
+		--decorate-refs="refs/heads" >actual &&
+	! grep HEAD actual
+'
+
+test_expect_success '--clear-decorations overrides defaults' '
+	cat >expect.default <<-\EOF &&
+	Merge-tag-reach (HEAD -> refs/heads/main)
+	Merge-tags-octopus-a-and-octopus-b
+	seventh (tag: refs/tags/seventh)
+	octopus-b (tag: refs/tags/octopus-b, refs/heads/octopus-b)
+	octopus-a (tag: refs/tags/octopus-a, refs/heads/octopus-a)
+	reach (tag: refs/tags/reach, refs/heads/reach)
+	Merge-branch-tangle
+	Merge-branch-side-early-part-into-tangle (refs/heads/tangle)
+	Merge-branch-main-early-part-into-tangle
+	tangle-a (tag: refs/tags/tangle-a)
+	Merge-branch-side
+	side-2 (tag: refs/tags/side-2, refs/heads/side)
+	side-1 (tag: refs/tags/side-1)
+	Second
+	sixth
+	fifth
+	fourth
+	third
+	second
+	initial
+	EOF
+	git log --decorate=full --pretty="tformat:%f%d" >actual &&
+	test_cmp expect.default actual &&
+
+	cat >expect.all <<-\EOF &&
+	Merge-tag-reach (HEAD -> refs/heads/main)
+	Merge-tags-octopus-a-and-octopus-b
+	seventh (tag: refs/tags/seventh)
+	octopus-b (tag: refs/tags/octopus-b, refs/heads/octopus-b)
+	octopus-a (tag: refs/tags/octopus-a, refs/heads/octopus-a)
+	reach (tag: refs/tags/reach, refs/heads/reach)
+	Merge-branch-tangle (refs/hidden/tangle)
+	Merge-branch-side-early-part-into-tangle (refs/rewritten/merge, refs/heads/tangle)
+	Merge-branch-main-early-part-into-tangle (refs/prefetch/merge)
+	tangle-a (tag: refs/tags/tangle-a)
+	Merge-branch-side
+	side-2 (tag: refs/tags/side-2, refs/heads/side)
+	side-1 (tag: refs/tags/side-1)
+	Second
+	sixth
+	fifth
+	fourth
+	third
+	second
+	initial
+	EOF
+	git log --decorate=full --pretty="tformat:%f%d" \
+		--clear-decorations >actual &&
+	test_cmp expect.all actual &&
+	git -c log.initialDecorationSet=all log \
+		--decorate=full --pretty="tformat:%f%d" >actual &&
+	test_cmp expect.all actual
+'
+
+test_expect_success '--clear-decorations clears previous exclusions' '
+	cat >expect.all <<-\EOF &&
+	Merge-tag-reach (HEAD -> refs/heads/main)
+	reach (tag: refs/tags/reach, refs/heads/reach)
+	Merge-tags-octopus-a-and-octopus-b
+	octopus-b (tag: refs/tags/octopus-b, refs/heads/octopus-b)
+	octopus-a (tag: refs/tags/octopus-a, refs/heads/octopus-a)
+	seventh (tag: refs/tags/seventh)
+	Merge-branch-tangle (refs/hidden/tangle)
+	Merge-branch-side-early-part-into-tangle (refs/rewritten/merge, refs/heads/tangle)
+	Merge-branch-main-early-part-into-tangle (refs/prefetch/merge)
+	tangle-a (tag: refs/tags/tangle-a)
+	side-2 (tag: refs/tags/side-2, refs/heads/side)
+	side-1 (tag: refs/tags/side-1)
+	initial
+	EOF
+
+	git log --decorate=full --pretty="tformat:%f%d" \
+		--simplify-by-decoration \
+		--decorate-refs-exclude="heads/octopus*" \
+		--decorate-refs="heads" \
+		--clear-decorations >actual &&
+	test_cmp expect.all actual &&
+
+	cat >expect.filtered <<-\EOF &&
+	Merge-tags-octopus-a-and-octopus-b
+	octopus-b (refs/heads/octopus-b)
+	octopus-a (refs/heads/octopus-a)
+	initial
+	EOF
+
+	git log --decorate=full --pretty="tformat:%f%d" \
+		--simplify-by-decoration \
+		--decorate-refs-exclude="heads/octopus" \
+		--decorate-refs="heads" \
+		--clear-decorations \
+		--decorate-refs-exclude="tags/" \
+		--decorate-refs="heads/octopus*" >actual &&
+	test_cmp expect.filtered actual
+'
+
 test_expect_success 'log.decorate config parsing' '
 	git log --oneline --decorate=full >expect.full &&
 	git log --oneline --decorate=short >expect.short &&
@@ -2112,9 +2224,9 @@
 	test_i18ngrep broken stderr
 '
 
-test_expect_success 'log diagnoses bogus HEAD symref' '
+test_expect_success REFFILES 'log diagnoses bogus HEAD symref' '
 	git init empty &&
-	git --git-dir empty/.git symbolic-ref HEAD refs/heads/invalid.lock &&
+	echo "ref: refs/heads/invalid.lock" > empty/.git/HEAD &&
 	test_must_fail git -C empty log 2>stderr &&
 	test_i18ngrep broken stderr &&
 	test_must_fail git -C empty log --default totally-bogus 2>stderr &&
@@ -2192,6 +2304,20 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'log --decorate does not include things outside filter' '
+	reflist="refs/prefetch refs/rebase-merge refs/bundle" &&
+
+	for ref in $reflist
+	do
+		git update-ref $ref/fake HEAD || return 1
+	done &&
+
+	git log --decorate=full --oneline >actual &&
+
+	# None of the refs are visible:
+	! grep /fake actual
+'
+
 test_expect_success 'log --end-of-options' '
        git update-ref refs/heads/--source HEAD &&
        git log --end-of-options --source >actual &&
diff --git a/t/t4203-mailmap.sh b/t/t4203-mailmap.sh
index 0b2d21e..cd1cab3 100755
--- a/t/t4203-mailmap.sh
+++ b/t/t4203-mailmap.sh
@@ -963,4 +963,63 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'prepare for cat-file --mailmap' '
+	rm -f .mailmap &&
+	git commit --allow-empty -m foo --author="Orig <orig@example.com>"
+'
+
+test_expect_success '--no-use-mailmap disables mailmap in cat-file' '
+	test_when_finished "rm .mailmap" &&
+	cat >.mailmap <<-EOF &&
+	A U Thor <author@example.com> Orig <orig@example.com>
+	EOF
+	cat >expect <<-EOF &&
+	author Orig <orig@example.com>
+	EOF
+	git cat-file --no-use-mailmap commit HEAD >log &&
+	sed -n "/^author /s/\([^>]*>\).*/\1/p" log >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--use-mailmap enables mailmap in cat-file' '
+	test_when_finished "rm .mailmap" &&
+	cat >.mailmap <<-EOF &&
+	A U Thor <author@example.com> Orig <orig@example.com>
+	EOF
+	cat >expect <<-EOF &&
+	author A U Thor <author@example.com>
+	EOF
+	git cat-file --use-mailmap commit HEAD >log &&
+	sed -n "/^author /s/\([^>]*>\).*/\1/p" log >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--no-mailmap disables mailmap in cat-file for annotated tag objects' '
+	test_when_finished "rm .mailmap" &&
+	cat >.mailmap <<-EOF &&
+	Orig <orig@example.com> C O Mitter <committer@example.com>
+	EOF
+	cat >expect <<-EOF &&
+	tagger C O Mitter <committer@example.com>
+	EOF
+	git tag -a -m "annotated tag" v1 &&
+	git cat-file --no-mailmap -p v1 >log &&
+	sed -n "/^tagger /s/\([^>]*>\).*/\1/p" log >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--mailmap enables mailmap in cat-file for annotated tag objects' '
+	test_when_finished "rm .mailmap" &&
+	cat >.mailmap <<-EOF &&
+	Orig <orig@example.com> C O Mitter <committer@example.com>
+	EOF
+	cat >expect <<-EOF &&
+	tagger Orig <orig@example.com>
+	EOF
+	git tag -a -m "annotated tag" v2 &&
+	git cat-file --mailmap -p v2 >log &&
+	sed -n "/^tagger /s/\([^>]*>\).*/\1/p" log >actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t4207-log-decoration-colors.sh b/t/t4207-log-decoration-colors.sh
index 36ac6af..ded33a8 100755
--- a/t/t4207-log-decoration-colors.sh
+++ b/t/t4207-log-decoration-colors.sh
@@ -3,7 +3,7 @@
 # Copyright (c) 2010 Nazri Ramliy
 #
 
-test_description='Test for "git log --decorate" colors'
+test_description='test "git log --decorate" colors'
 
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
@@ -17,6 +17,7 @@
 	git config color.decorate.remoteBranch red &&
 	git config color.decorate.tag "reverse bold yellow" &&
 	git config color.decorate.stash magenta &&
+	git config color.decorate.grafted black &&
 	git config color.decorate.HEAD cyan &&
 
 	c_reset="<RESET>" &&
@@ -27,6 +28,7 @@
 	c_tag="<BOLD;REVERSE;YELLOW>" &&
 	c_stash="<MAGENTA>" &&
 	c_HEAD="<CYAN>" &&
+	c_grafted="<BLACK>" &&
 
 	test_commit A &&
 	git clone . other &&
@@ -42,25 +44,79 @@
 	git stash save Changes to A.t
 '
 
-cat >expected <<EOF
-${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_HEAD}HEAD ->\
- ${c_reset}${c_branch}main${c_reset}${c_commit},\
- ${c_reset}${c_tag}tag: v1.0${c_reset}${c_commit},\
- ${c_reset}${c_tag}tag: B${c_reset}${c_commit})${c_reset} B
-${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_tag}tag: A1${c_reset}${c_commit},\
- ${c_reset}${c_remoteBranch}other/main${c_reset}${c_commit})${c_reset} A1
-${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_stash}refs/stash${c_reset}${c_commit})${c_reset}\
- On main: Changes to A.t
-${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_tag}tag: A${c_reset}${c_commit})${c_reset} A
-EOF
+cmp_filtered_decorations () {
+	sed "s/$OID_REGEX/COMMIT_ID/" actual | test_decode_color >filtered &&
+	test_cmp expect filtered
+}
 
 # We want log to show all, but the second parent to refs/stash is irrelevant
 # to this test since it does not contain any decoration, hence --first-parent
-test_expect_success 'Commit Decorations Colored Correctly' '
-	git log --first-parent --abbrev=10 --all --decorate --oneline --color=always |
-	sed "s/[0-9a-f]\{10,10\}/COMMIT_ID/" |
-	test_decode_color >out &&
-	test_cmp expected out
+test_expect_success 'commit decorations colored correctly' '
+	cat >expect <<-EOF &&
+	${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_HEAD}HEAD -> \
+${c_reset}${c_branch}main${c_reset}${c_commit}, \
+${c_reset}${c_tag}tag: v1.0${c_reset}${c_commit}, \
+${c_reset}${c_tag}tag: B${c_reset}${c_commit})${c_reset} B
+${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_tag}tag: A1${c_reset}${c_commit}, \
+${c_reset}${c_remoteBranch}other/main${c_reset}${c_commit})${c_reset} A1
+	${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_stash}refs/stash${c_reset}${c_commit})${c_reset} \
+On main: Changes to A.t
+	${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_tag}tag: A${c_reset}${c_commit})${c_reset} A
+	EOF
+
+	git log --first-parent --no-abbrev --decorate --oneline --color=always --all >actual &&
+	cmp_filtered_decorations
+'
+
+test_expect_success 'test coloring with replace-objects' '
+	test_when_finished rm -rf .git/refs/replace* &&
+	test_commit C &&
+	test_commit D &&
+
+	git replace HEAD~1 HEAD~2 &&
+
+	cat >expect <<-EOF &&
+	${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_HEAD}HEAD -> \
+${c_reset}${c_branch}main${c_reset}${c_commit}, \
+${c_reset}${c_tag}tag: D${c_reset}${c_commit})${c_reset} D
+	${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_tag}tag: C${c_reset}${c_commit}, \
+${c_reset}${c_grafted}replaced${c_reset}${c_commit})${c_reset} B
+	${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_tag}tag: A${c_reset}${c_commit})${c_reset} A
+EOF
+
+	git log --first-parent --no-abbrev --decorate --oneline --color=always HEAD >actual &&
+	cmp_filtered_decorations &&
+	git replace -d HEAD~1 &&
+
+	GIT_REPLACE_REF_BASE=refs/replace2/ git replace HEAD~1 HEAD~2 &&
+	GIT_REPLACE_REF_BASE=refs/replace2/ git log --first-parent \
+		--no-abbrev --decorate --oneline --color=always HEAD >actual &&
+	cmp_filtered_decorations
+'
+
+test_expect_success 'test coloring with grafted commit' '
+	test_when_finished rm -rf .git/refs/replace* &&
+
+	git replace --graft HEAD HEAD~2 &&
+
+	cat >expect <<-EOF &&
+	${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_HEAD}HEAD -> \
+${c_reset}${c_branch}main${c_reset}${c_commit}, \
+${c_reset}${c_tag}tag: D${c_reset}${c_commit}, \
+${c_reset}${c_grafted}replaced${c_reset}${c_commit})${c_reset} D
+	${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_tag}tag: v1.0${c_reset}${c_commit}, \
+${c_reset}${c_tag}tag: B${c_reset}${c_commit})${c_reset} B
+	${c_commit}COMMIT_ID${c_reset}${c_commit} (${c_reset}${c_tag}tag: A${c_reset}${c_commit})${c_reset} A
+	EOF
+
+	git log --first-parent --no-abbrev --decorate --oneline --color=always HEAD >actual &&
+	cmp_filtered_decorations &&
+	git replace -d HEAD &&
+
+	GIT_REPLACE_REF_BASE=refs/replace2/ git replace --graft HEAD HEAD~2 &&
+	GIT_REPLACE_REF_BASE=refs/replace2/ git log --first-parent \
+		--no-abbrev --decorate --oneline --color=always HEAD >actual &&
+	cmp_filtered_decorations
 '
 
 test_done
diff --git a/t/t4301-merge-tree-write-tree.sh b/t/t4301-merge-tree-write-tree.sh
new file mode 100755
index 0000000..28ca5c3
--- /dev/null
+++ b/t/t4301-merge-tree-write-tree.sh
@@ -0,0 +1,813 @@
+#!/bin/sh
+
+test_description='git merge-tree --write-tree'
+
+. ./test-lib.sh
+
+# This test is ort-specific
+if test "$GIT_TEST_MERGE_ALGORITHM" != "ort"
+then
+	skip_all="GIT_TEST_MERGE_ALGORITHM != ort"
+	test_done
+fi
+
+test_expect_success setup '
+	test_write_lines 1 2 3 4 5 >numbers &&
+	echo hello >greeting &&
+	echo foo >whatever &&
+	git add numbers greeting whatever &&
+	test_tick &&
+	git commit -m initial &&
+
+	git branch side1 &&
+	git branch side2 &&
+	git branch side3 &&
+
+	git checkout side1 &&
+	test_write_lines 1 2 3 4 5 6 >numbers &&
+	echo hi >greeting &&
+	echo bar >whatever &&
+	git add numbers greeting whatever &&
+	test_tick &&
+	git commit -m modify-stuff &&
+
+	git checkout side2 &&
+	test_write_lines 0 1 2 3 4 5 >numbers &&
+	echo yo >greeting &&
+	git rm whatever &&
+	mkdir whatever &&
+	>whatever/empty &&
+	git add numbers greeting whatever/empty &&
+	test_tick &&
+	git commit -m other-modifications &&
+
+	git checkout side3 &&
+	git mv numbers sequence &&
+	test_tick &&
+	git commit -m rename-numbers &&
+
+	git switch --orphan unrelated &&
+	>something-else &&
+	git add something-else &&
+	test_tick &&
+	git commit -m first-commit
+'
+
+test_expect_success 'Clean merge' '
+	TREE_OID=$(git merge-tree --write-tree side1 side3) &&
+	q_to_tab <<-EOF >expect &&
+	100644 blob $(git rev-parse side1:greeting)Qgreeting
+	100644 blob $(git rev-parse side1:numbers)Qsequence
+	100644 blob $(git rev-parse side1:whatever)Qwhatever
+	EOF
+
+	git ls-tree $TREE_OID >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'Content merge and a few conflicts' '
+	git checkout side1^0 &&
+	test_must_fail git merge side2 &&
+	expected_tree=$(git rev-parse AUTO_MERGE) &&
+
+	# We will redo the merge, while we are still in a conflicted state!
+	git ls-files -u >conflicted-file-info &&
+	test_when_finished "git reset --hard" &&
+
+	test_expect_code 1 git merge-tree --write-tree side1 side2 >RESULT &&
+	actual_tree=$(head -n 1 RESULT) &&
+
+	# Due to differences of e.g. "HEAD" vs "side1", the results will not
+	# exactly match.  Dig into individual files.
+
+	# Numbers should have three-way merged cleanly
+	test_write_lines 0 1 2 3 4 5 6 >expect &&
+	git show ${actual_tree}:numbers >actual &&
+	test_cmp expect actual &&
+
+	# whatever and whatever~<branch> should have same HASHES
+	git rev-parse ${expected_tree}:whatever ${expected_tree}:whatever~HEAD >expect &&
+	git rev-parse ${actual_tree}:whatever ${actual_tree}:whatever~side1 >actual &&
+	test_cmp expect actual &&
+
+	# greeting should have a merge conflict
+	git show ${expected_tree}:greeting >tmp &&
+	sed -e s/HEAD/side1/ tmp >expect &&
+	git show ${actual_tree}:greeting >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'Barf on misspelled option, with exit code other than 0 or 1' '
+	# Mis-spell with single "s" instead of double "s"
+	test_expect_code 129 git merge-tree --write-tree --mesages FOOBAR side1 side2 2>expect &&
+
+	grep "error: unknown option.*mesages" expect
+'
+
+test_expect_success 'Barf on too many arguments' '
+	test_expect_code 129 git merge-tree --write-tree side1 side2 invalid 2>expect &&
+
+	grep "^usage: git merge-tree" expect
+'
+
+anonymize_hash() {
+	sed -e "s/[0-9a-f]\{40,\}/HASH/g" "$@"
+}
+
+test_expect_success 'test conflict notices and such' '
+	test_expect_code 1 git merge-tree --write-tree --name-only side1 side2 >out &&
+	anonymize_hash out >actual &&
+
+	# Expected results:
+	#   "greeting" should merge with conflicts
+	#   "numbers" should merge cleanly
+	#   "whatever" has *both* a modify/delete and a file/directory conflict
+	cat <<-EOF >expect &&
+	HASH
+	greeting
+	whatever~side1
+
+	Auto-merging greeting
+	CONFLICT (content): Merge conflict in greeting
+	Auto-merging numbers
+	CONFLICT (file/directory): directory in the way of whatever from side1; moving it to whatever~side1 instead.
+	CONFLICT (modify/delete): whatever~side1 deleted in side2 and modified in side1.  Version side1 of whatever~side1 left in tree.
+	EOF
+
+	test_cmp expect actual
+'
+
+# directory rename + content conflict
+#   Commit O: foo, olddir/{a,b,c}
+#   Commit A: modify foo, newdir/{a,b,c}
+#   Commit B: modify foo differently & rename foo -> olddir/bar
+#   Expected: CONFLICT(content) for for newdir/bar (not olddir/bar or foo)
+
+test_expect_success 'directory rename + content conflict' '
+	# Setup
+	git init dir-rename-and-content &&
+	(
+		cd dir-rename-and-content &&
+		test_write_lines 1 2 3 4 5 >foo &&
+		mkdir olddir &&
+		for i in a b c; do echo $i >olddir/$i || exit 1; done &&
+		git add foo olddir &&
+		git commit -m "original" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_write_lines 1 2 3 4 5 6 >foo &&
+		git add foo &&
+		git mv olddir newdir &&
+		git commit -m "Modify foo, rename olddir to newdir" &&
+
+		git checkout B &&
+		test_write_lines 1 2 3 4 5 six >foo &&
+		git add foo &&
+		git mv foo olddir/bar &&
+		git commit -m "Modify foo & rename foo -> olddir/bar"
+	) &&
+	# Testing
+	(
+		cd dir-rename-and-content &&
+
+		test_expect_code 1 \
+			git merge-tree -z A^0 B^0 >out &&
+		echo >>out &&
+		anonymize_hash out >actual &&
+		q_to_tab <<-\EOF | lf_to_nul >expect &&
+		HASH
+		100644 HASH 1Qnewdir/bar
+		100644 HASH 2Qnewdir/bar
+		100644 HASH 3Qnewdir/bar
+		EOF
+
+		q_to_nul <<-EOF >>expect &&
+		Q2Qnewdir/barQolddir/barQCONFLICT (directory rename suggested)QCONFLICT (file location): foo renamed to olddir/bar in B^0, inside a directory that was renamed in A^0, suggesting it should perhaps be moved to newdir/bar.
+		Q1Qnewdir/barQAuto-mergingQAuto-merging newdir/bar
+		Q1Qnewdir/barQCONFLICT (contents)QCONFLICT (content): Merge conflict in newdir/bar
+		Q
+		EOF
+		test_cmp expect actual
+	)
+'
+
+# rename/delete + modify/delete handling
+#   Commit O: foo
+#   Commit A: modify foo + rename to bar
+#   Commit B: delete foo
+#   Expected: CONFLICT(rename/delete) + CONFLICT(modify/delete)
+
+test_expect_success 'rename/delete handling' '
+	# Setup
+	git init rename-delete &&
+	(
+		cd rename-delete &&
+		test_write_lines 1 2 3 4 5 >foo &&
+		git add foo &&
+		git commit -m "original" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_write_lines 1 2 3 4 5 6 >foo &&
+		git add foo &&
+		git mv foo bar &&
+		git commit -m "Modify foo, rename to bar" &&
+
+		git checkout B &&
+		git rm foo &&
+		git commit -m "remove foo"
+	) &&
+	# Testing
+	(
+		cd rename-delete &&
+
+		test_expect_code 1 \
+			git merge-tree -z A^0 B^0 >out &&
+		echo >>out &&
+		anonymize_hash out >actual &&
+		q_to_tab <<-\EOF | lf_to_nul >expect &&
+		HASH
+		100644 HASH 1Qbar
+		100644 HASH 2Qbar
+		EOF
+
+		q_to_nul <<-EOF >>expect &&
+		Q2QbarQfooQCONFLICT (rename/delete)QCONFLICT (rename/delete): foo renamed to bar in A^0, but deleted in B^0.
+		Q1QbarQCONFLICT (modify/delete)QCONFLICT (modify/delete): bar deleted in B^0 and modified in A^0.  Version A^0 of bar left in tree.
+		Q
+		EOF
+		test_cmp expect actual
+	)
+'
+
+# rename/add handling
+#   Commit O: foo
+#   Commit A: modify foo, add different bar
+#   Commit B: modify & rename foo->bar
+#   Expected: CONFLICT(add/add) [via rename collide] for bar
+
+test_expect_success 'rename/add handling' '
+	# Setup
+	git init rename-add &&
+	(
+		cd rename-add &&
+		test_write_lines original 1 2 3 4 5 >foo &&
+		git add foo &&
+		git commit -m "original" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_write_lines 1 2 3 4 5 >foo &&
+		echo "different file" >bar &&
+		git add foo bar &&
+		git commit -m "Modify foo, add bar" &&
+
+		git checkout B &&
+		test_write_lines original 1 2 3 4 5 6 >foo &&
+		git add foo &&
+		git mv foo bar &&
+		git commit -m "rename foo to bar"
+	) &&
+	# Testing
+	(
+		cd rename-add &&
+
+		test_expect_code 1 \
+			git merge-tree -z A^0 B^0 >out &&
+		echo >>out &&
+
+		#
+		# First, check that the bar that appears at stage 3 does not
+		# correspond to an individual blob anywhere in history
+		#
+		hash=$(cat out | tr "\0" "\n" | head -n 3 | grep 3.bar | cut -f 2 -d " ") &&
+		git rev-list --objects --all >all_blobs &&
+		! grep $hash all_blobs &&
+
+		#
+		# Second, check anonymized hash output against expectation
+		#
+		anonymize_hash out >actual &&
+		q_to_tab <<-\EOF | lf_to_nul >expect &&
+		HASH
+		100644 HASH 2Qbar
+		100644 HASH 3Qbar
+		EOF
+
+		q_to_nul <<-EOF >>expect &&
+		Q1QbarQAuto-mergingQAuto-merging bar
+		Q1QbarQCONFLICT (contents)QCONFLICT (add/add): Merge conflict in bar
+		Q1QfooQAuto-mergingQAuto-merging foo
+		Q
+		EOF
+		test_cmp expect actual
+	)
+'
+
+# rename/add, where add is a mode conflict
+#   Commit O: foo
+#   Commit A: modify foo, add symlink bar
+#   Commit B: modify & rename foo->bar
+#   Expected: CONFLICT(distinct modes) for bar
+
+test_expect_success SYMLINKS 'rename/add, where add is a mode conflict' '
+	# Setup
+	git init rename-add-symlink &&
+	(
+		cd rename-add-symlink &&
+		test_write_lines original 1 2 3 4 5 >foo &&
+		git add foo &&
+		git commit -m "original" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_write_lines 1 2 3 4 5 >foo &&
+		ln -s foo bar &&
+		git add foo bar &&
+		git commit -m "Modify foo, add symlink bar" &&
+
+		git checkout B &&
+		test_write_lines original 1 2 3 4 5 6 >foo &&
+		git add foo &&
+		git mv foo bar &&
+		git commit -m "rename foo to bar"
+	) &&
+	# Testing
+	(
+		cd rename-add-symlink &&
+
+		test_expect_code 1 \
+			git merge-tree -z A^0 B^0 >out &&
+		echo >>out &&
+
+		#
+		# First, check that the bar that appears at stage 3 does not
+		# correspond to an individual blob anywhere in history
+		#
+		hash=$(cat out | tr "\0" "\n" | head -n 3 | grep 3.bar | cut -f 2 -d " ") &&
+		git rev-list --objects --all >all_blobs &&
+		! grep $hash all_blobs &&
+
+		#
+		# Second, check anonymized hash output against expectation
+		#
+		anonymize_hash out >actual &&
+		q_to_tab <<-\EOF | lf_to_nul >expect &&
+		HASH
+		120000 HASH 2Qbar
+		100644 HASH 3Qbar~B^0
+		EOF
+
+		q_to_nul <<-EOF >>expect &&
+		Q2QbarQbar~B^0QCONFLICT (distinct modes)QCONFLICT (distinct types): bar had different types on each side; renamed one of them so each can be recorded somewhere.
+		Q1QfooQAuto-mergingQAuto-merging foo
+		Q
+		EOF
+		test_cmp expect actual
+	)
+'
+
+# rename/rename(1to2) + content conflict handling
+#   Commit O: foo
+#   Commit A: modify foo & rename to bar
+#   Commit B: modify foo & rename to baz
+#   Expected: CONFLICT(rename/rename)
+
+test_expect_success 'rename/rename + content conflict' '
+	# Setup
+	git init rr-plus-content &&
+	(
+		cd rr-plus-content &&
+		test_write_lines 1 2 3 4 5 >foo &&
+		git add foo &&
+		git commit -m "original" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_write_lines 1 2 3 4 5 six >foo &&
+		git add foo &&
+		git mv foo bar &&
+		git commit -m "Modify foo + rename to bar" &&
+
+		git checkout B &&
+		test_write_lines 1 2 3 4 5 6 >foo &&
+		git add foo &&
+		git mv foo baz &&
+		git commit -m "Modify foo + rename to baz"
+	) &&
+	# Testing
+	(
+		cd rr-plus-content &&
+
+		test_expect_code 1 \
+			git merge-tree -z A^0 B^0 >out &&
+		echo >>out &&
+		anonymize_hash out >actual &&
+		q_to_tab <<-\EOF | lf_to_nul >expect &&
+		HASH
+		100644 HASH 2Qbar
+		100644 HASH 3Qbaz
+		100644 HASH 1Qfoo
+		EOF
+
+		q_to_nul <<-EOF >>expect &&
+		Q1QfooQAuto-mergingQAuto-merging foo
+		Q3QfooQbarQbazQCONFLICT (rename/rename)QCONFLICT (rename/rename): foo renamed to bar in A^0 and to baz in B^0.
+		Q
+		EOF
+		test_cmp expect actual
+	)
+'
+
+# rename/add/delete
+#   Commit O: foo
+#   Commit A: rm foo, add different bar
+#   Commit B: rename foo->bar
+#   Expected: CONFLICT (rename/delete), CONFLICT(add/add) [via rename collide]
+#             for bar
+
+test_expect_success 'rename/add/delete conflict' '
+	# Setup
+	git init rad &&
+	(
+		cd rad &&
+		echo "original file" >foo &&
+		git add foo &&
+		git commit -m "original" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git rm foo &&
+		echo "different file" >bar &&
+		git add bar &&
+		git commit -m "Remove foo, add bar" &&
+
+		git checkout B &&
+		git mv foo bar &&
+		git commit -m "rename foo to bar"
+	) &&
+	# Testing
+	(
+		cd rad &&
+
+		test_expect_code 1 \
+			git merge-tree -z B^0 A^0 >out &&
+		echo >>out &&
+		anonymize_hash out >actual &&
+
+		q_to_tab <<-\EOF | lf_to_nul >expect &&
+		HASH
+		100644 HASH 2Qbar
+		100644 HASH 3Qbar
+
+		EOF
+
+		q_to_nul <<-EOF >>expect &&
+		2QbarQfooQCONFLICT (rename/delete)QCONFLICT (rename/delete): foo renamed to bar in B^0, but deleted in A^0.
+		Q1QbarQAuto-mergingQAuto-merging bar
+		Q1QbarQCONFLICT (contents)QCONFLICT (add/add): Merge conflict in bar
+		Q
+		EOF
+		test_cmp expect actual
+	)
+'
+
+# rename/rename(2to1)/delete/delete
+#   Commit O: foo, bar
+#   Commit A: rename foo->baz, rm bar
+#   Commit B: rename bar->baz, rm foo
+#   Expected: 2x CONFLICT (rename/delete), CONFLICT (add/add) via colliding
+#             renames for baz
+
+test_expect_success 'rename/rename(2to1)/delete/delete conflict' '
+	# Setup
+	git init rrdd &&
+	(
+		cd rrdd &&
+		echo foo >foo &&
+		echo bar >bar &&
+		git add foo bar &&
+		git commit -m O &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git mv foo baz &&
+		git rm bar &&
+		git commit -m "Rename foo, remove bar" &&
+
+		git checkout B &&
+		git mv bar baz &&
+		git rm foo &&
+		git commit -m "Rename bar, remove foo"
+	) &&
+	# Testing
+	(
+		cd rrdd &&
+
+		test_expect_code 1 \
+			git merge-tree -z A^0 B^0 >out &&
+		echo >>out &&
+		anonymize_hash out >actual &&
+
+		q_to_tab <<-\EOF | lf_to_nul >expect &&
+		HASH
+		100644 HASH 2Qbaz
+		100644 HASH 3Qbaz
+
+		EOF
+
+		q_to_nul <<-EOF >>expect &&
+		2QbazQbarQCONFLICT (rename/delete)QCONFLICT (rename/delete): bar renamed to baz in B^0, but deleted in A^0.
+		Q2QbazQfooQCONFLICT (rename/delete)QCONFLICT (rename/delete): foo renamed to baz in A^0, but deleted in B^0.
+		Q1QbazQAuto-mergingQAuto-merging baz
+		Q1QbazQCONFLICT (contents)QCONFLICT (add/add): Merge conflict in baz
+		Q
+		EOF
+		test_cmp expect actual
+	)
+'
+
+# mod6: chains of rename/rename(1to2) + add/add via colliding renames
+#   Commit O: one,      three,       five
+#   Commit A: one->two, three->four, five->six
+#   Commit B: one->six, three->two,  five->four
+#   Expected: three CONFLICT(rename/rename) messages + three CONFLICT(add/add)
+#             messages; each path in two of the multi-way merged contents
+#             found in two, four, six
+
+test_expect_success 'mod6: chains of rename/rename(1to2) and add/add via colliding renames' '
+	# Setup
+	git init mod6 &&
+	(
+		cd mod6 &&
+		test_seq 11 19 >one &&
+		test_seq 31 39 >three &&
+		test_seq 51 59 >five &&
+		git add . &&
+		test_tick &&
+		git commit -m "O" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		test_seq 10 19 >one &&
+		echo 40        >>three &&
+		git add one three &&
+		git mv  one   two  &&
+		git mv  three four &&
+		git mv  five  six  &&
+		test_tick &&
+		git commit -m "A" &&
+
+		git checkout B &&
+		echo 20    >>one       &&
+		echo forty >>three     &&
+		echo 60    >>five      &&
+		git add one three five &&
+		git mv  one   six  &&
+		git mv  three two  &&
+		git mv  five  four &&
+		test_tick &&
+		git commit -m "B"
+	) &&
+	# Testing
+	(
+		cd mod6 &&
+
+		test_expect_code 1 \
+			git merge-tree -z A^0 B^0 >out &&
+		echo >>out &&
+
+		#
+		# First, check that some of the hashes that appear as stage
+		# conflict entries do not appear as individual blobs anywhere
+		# in history.
+		#
+		hash1=$(cat out | tr "\0" "\n" | head | grep 2.four | cut -f 2 -d " ") &&
+		hash2=$(cat out | tr "\0" "\n" | head | grep 3.two | cut -f 2 -d " ") &&
+		git rev-list --objects --all >all_blobs &&
+		! grep $hash1 all_blobs &&
+		! grep $hash2 all_blobs &&
+
+		#
+		# Now compare anonymized hash output with expectation
+		#
+		anonymize_hash out >actual &&
+		q_to_tab <<-\EOF | lf_to_nul >expect &&
+		HASH
+		100644 HASH 1Qfive
+		100644 HASH 2Qfour
+		100644 HASH 3Qfour
+		100644 HASH 1Qone
+		100644 HASH 2Qsix
+		100644 HASH 3Qsix
+		100644 HASH 1Qthree
+		100644 HASH 2Qtwo
+		100644 HASH 3Qtwo
+
+		EOF
+
+		q_to_nul <<-EOF >>expect &&
+		3QfiveQsixQfourQCONFLICT (rename/rename)QCONFLICT (rename/rename): five renamed to six in A^0 and to four in B^0.
+		Q1QfourQAuto-mergingQAuto-merging four
+		Q1QfourQCONFLICT (contents)QCONFLICT (add/add): Merge conflict in four
+		Q1QoneQAuto-mergingQAuto-merging one
+		Q3QoneQtwoQsixQCONFLICT (rename/rename)QCONFLICT (rename/rename): one renamed to two in A^0 and to six in B^0.
+		Q1QsixQAuto-mergingQAuto-merging six
+		Q1QsixQCONFLICT (contents)QCONFLICT (add/add): Merge conflict in six
+		Q1QthreeQAuto-mergingQAuto-merging three
+		Q3QthreeQfourQtwoQCONFLICT (rename/rename)QCONFLICT (rename/rename): three renamed to four in A^0 and to two in B^0.
+		Q1QtwoQAuto-mergingQAuto-merging two
+		Q1QtwoQCONFLICT (contents)QCONFLICT (add/add): Merge conflict in two
+		Q
+		EOF
+		test_cmp expect actual
+	)
+'
+
+# directory rename + rename/delete + modify/delete + directory/file conflict
+#   Commit O: foo, olddir/{a,b,c}
+#   Commit A: delete foo, rename olddir/ -> newdir/, add newdir/bar/file
+#   Commit B: modify foo & rename foo -> olddir/bar
+#   Expected: CONFLICT(content) for for newdir/bar (not olddir/bar or foo)
+
+test_expect_success 'directory rename + rename/delete + modify/delete + directory/file conflict' '
+	# Setup
+	git init 4-stacked-conflict &&
+	(
+		cd 4-stacked-conflict &&
+		test_write_lines 1 2 3 4 5 >foo &&
+		mkdir olddir &&
+		for i in a b c; do echo $i >olddir/$i || exit 1; done &&
+		git add foo olddir &&
+		git commit -m "original" &&
+
+		git branch O &&
+		git branch A &&
+		git branch B &&
+
+		git checkout A &&
+		git rm foo &&
+		git mv olddir newdir &&
+		mkdir newdir/bar &&
+		>newdir/bar/file &&
+		git add newdir/bar/file &&
+		git commit -m "rm foo, olddir/ -> newdir/, + newdir/bar/file" &&
+
+		git checkout B &&
+		test_write_lines 1 2 3 4 5 6 >foo &&
+		git add foo &&
+		git mv foo olddir/bar &&
+		git commit -m "Modify foo & rename foo -> olddir/bar"
+	) &&
+	# Testing
+	(
+		cd 4-stacked-conflict &&
+
+		test_expect_code 1 \
+			git merge-tree -z A^0 B^0 >out &&
+		echo >>out &&
+		anonymize_hash out >actual &&
+
+		q_to_tab <<-\EOF | lf_to_nul >expect &&
+		HASH
+		100644 HASH 1Qnewdir/bar~B^0
+		100644 HASH 3Qnewdir/bar~B^0
+		EOF
+
+		q_to_nul <<-EOF >>expect &&
+		Q2Qnewdir/barQolddir/barQCONFLICT (directory rename suggested)QCONFLICT (file location): foo renamed to olddir/bar in B^0, inside a directory that was renamed in A^0, suggesting it should perhaps be moved to newdir/bar.
+		Q2Qnewdir/barQfooQCONFLICT (rename/delete)QCONFLICT (rename/delete): foo renamed to newdir/bar in B^0, but deleted in A^0.
+		Q2Qnewdir/bar~B^0Qnewdir/barQCONFLICT (file/directory)QCONFLICT (file/directory): directory in the way of newdir/bar from B^0; moving it to newdir/bar~B^0 instead.
+		Q1Qnewdir/bar~B^0QCONFLICT (modify/delete)QCONFLICT (modify/delete): newdir/bar~B^0 deleted in A^0 and modified in B^0.  Version B^0 of newdir/bar~B^0 left in tree.
+		Q
+		EOF
+		test_cmp expect actual
+	)
+'
+
+for opt in $(git merge-tree --git-completion-helper-all)
+do
+	if test $opt = "--trivial-merge" || test $opt = "--write-tree"
+	then
+		continue
+	fi
+
+	test_expect_success "usage: --trivial-merge is incompatible with $opt" '
+		test_expect_code 128 git merge-tree --trivial-merge $opt side1 side2 side3
+	'
+done
+
+test_expect_success 'Just the conflicted files without the messages' '
+	test_expect_code 1 git merge-tree --write-tree --no-messages --name-only side1 side2 >out &&
+	anonymize_hash out >actual &&
+
+	test_write_lines HASH greeting whatever~side1 >expect &&
+
+	test_cmp expect actual
+'
+
+test_expect_success 'Check conflicted oids and modes without messages' '
+	test_expect_code 1 git merge-tree --write-tree --no-messages side1 side2 >out &&
+	anonymize_hash out >actual &&
+
+	# Compare the basic output format
+	q_to_tab >expect <<-\EOF &&
+	HASH
+	100644 HASH 1Qgreeting
+	100644 HASH 2Qgreeting
+	100644 HASH 3Qgreeting
+	100644 HASH 1Qwhatever~side1
+	100644 HASH 2Qwhatever~side1
+	EOF
+
+	test_cmp expect actual &&
+
+	# Check the actual hashes against the `ls-files -u` output too
+	tail -n +2 out | sed -e s/side1/HEAD/ >actual &&
+	test_cmp conflicted-file-info actual
+'
+
+test_expect_success 'NUL terminated conflicted file "lines"' '
+	git checkout -b tweak1 side1 &&
+	test_write_lines zero 1 2 3 4 5 6 >numbers &&
+	git add numbers &&
+	git mv numbers "Αυτά μου φαίνονται κινέζικα" &&
+	git commit -m "Renamed numbers" &&
+
+	test_expect_code 1 git merge-tree --write-tree -z tweak1 side2 >out &&
+	echo >>out &&
+	anonymize_hash out >actual &&
+
+	# Expected results:
+	#   "greeting" should merge with conflicts
+	#   "whatever" has *both* a modify/delete and a file/directory conflict
+	#   "Αυτά μου φαίνονται κινέζικα" should have a conflict
+	echo HASH | lf_to_nul >expect &&
+
+	q_to_tab <<-EOF | lf_to_nul >>expect &&
+	100644 HASH 1Qgreeting
+	100644 HASH 2Qgreeting
+	100644 HASH 3Qgreeting
+	100644 HASH 1Qwhatever~tweak1
+	100644 HASH 2Qwhatever~tweak1
+	100644 HASH 1QΑυτά μου φαίνονται κινέζικα
+	100644 HASH 2QΑυτά μου φαίνονται κινέζικα
+	100644 HASH 3QΑυτά μου φαίνονται κινέζικα
+
+	EOF
+
+	q_to_nul <<-EOF >>expect &&
+	1QgreetingQAuto-mergingQAuto-merging greeting
+	Q1QgreetingQCONFLICT (contents)QCONFLICT (content): Merge conflict in greeting
+	Q2Qwhatever~tweak1QwhateverQCONFLICT (file/directory)QCONFLICT (file/directory): directory in the way of whatever from tweak1; moving it to whatever~tweak1 instead.
+	Q1Qwhatever~tweak1QCONFLICT (modify/delete)QCONFLICT (modify/delete): whatever~tweak1 deleted in side2 and modified in tweak1.  Version tweak1 of whatever~tweak1 left in tree.
+	Q1QΑυτά μου φαίνονται κινέζικαQAuto-mergingQAuto-merging Αυτά μου φαίνονται κινέζικα
+	Q1QΑυτά μου φαίνονται κινέζικαQCONFLICT (contents)QCONFLICT (content): Merge conflict in Αυτά μου φαίνονται κινέζικα
+	Q
+	EOF
+
+	test_cmp expect actual
+'
+
+test_expect_success 'error out by default for unrelated histories' '
+	test_expect_code 128 git merge-tree --write-tree side1 unrelated 2>error &&
+
+	grep "refusing to merge unrelated histories" error
+'
+
+test_expect_success 'can override merge of unrelated histories' '
+	git merge-tree --write-tree --allow-unrelated-histories side1 unrelated >tree &&
+	TREE=$(cat tree) &&
+
+	git rev-parse side1:numbers side1:greeting side1:whatever unrelated:something-else >expect &&
+	git rev-parse $TREE:numbers $TREE:greeting $TREE:whatever $TREE:something-else >actual &&
+
+	test_cmp expect actual
+'
+
+test_done
diff --git a/t/t5000-tar-tree.sh b/t/t5000-tar-tree.sh
index 7f8d2ab..eaa0b22 100755
--- a/t/t5000-tar-tree.sh
+++ b/t/t5000-tar-tree.sh
@@ -24,6 +24,7 @@
 
 '
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 SUBSTFORMAT=%H%n
@@ -143,6 +144,7 @@
 test_expect_success \
     'add ignored file' \
     'echo ignore me >a/ignored &&
+     mkdir .git/info &&
      echo ignored export-ignore >.git/info/attributes'
 
 test_expect_success 'add files to repository' '
@@ -157,7 +159,8 @@
 '
 
 test_expect_success 'create bare clone' '
-	git clone --bare . bare.git &&
+	git clone --template= --bare . bare.git &&
+	mkdir bare.git/info &&
 	cp .git/info/attributes bare.git/info/attributes
 '
 
@@ -339,21 +342,21 @@
 	test_cmp_bin remote.bar config.bar
 '
 
-test_expect_success GZIP 'git archive --format=tgz' '
+test_expect_success 'git archive --format=tgz' '
 	git archive --format=tgz HEAD >j.tgz
 '
 
-test_expect_success GZIP 'git archive --format=tar.gz' '
+test_expect_success 'git archive --format=tar.gz' '
 	git archive --format=tar.gz HEAD >j1.tar.gz &&
 	test_cmp_bin j.tgz j1.tar.gz
 '
 
-test_expect_success GZIP 'infer tgz from .tgz filename' '
+test_expect_success 'infer tgz from .tgz filename' '
 	git archive --output=j2.tgz HEAD &&
 	test_cmp_bin j.tgz j2.tgz
 '
 
-test_expect_success GZIP 'infer tgz from .tar.gz filename' '
+test_expect_success 'infer tgz from .tar.gz filename' '
 	git archive --output=j3.tar.gz HEAD &&
 	test_cmp_bin j.tgz j3.tar.gz
 '
@@ -363,17 +366,33 @@
 	test_cmp_bin b.tar j.tar
 '
 
-test_expect_success GZIP 'remote tar.gz is allowed by default' '
+test_expect_success 'remote tar.gz is allowed by default' '
 	git archive --remote=. --format=tar.gz HEAD >remote.tar.gz &&
 	test_cmp_bin j.tgz remote.tar.gz
 '
 
-test_expect_success GZIP 'remote tar.gz can be disabled' '
+test_expect_success 'remote tar.gz can be disabled' '
 	git config tar.tar.gz.remote false &&
 	test_must_fail git archive --remote=. --format=tar.gz HEAD \
 		>remote.tar.gz
 '
 
+test_expect_success GZIP 'git archive --format=tgz (external gzip)' '
+	test_config tar.tgz.command "gzip -cn" &&
+	git archive --format=tgz HEAD >external_gzip.tgz
+'
+
+test_expect_success GZIP 'git archive --format=tar.gz (external gzip)' '
+	test_config tar.tar.gz.command "gzip -cn" &&
+	git archive --format=tar.gz HEAD >external_gzip.tar.gz &&
+	test_cmp_bin external_gzip.tgz external_gzip.tar.gz
+'
+
+test_expect_success GZIP 'extract tgz file (external gzip)' '
+	gzip -d -c <external_gzip.tgz >external_gzip.tar &&
+	test_cmp_bin b.tar external_gzip.tar
+'
+
 test_expect_success 'archive and :(glob)' '
 	git archive -v HEAD -- ":(glob)**/sh" >/dev/null 2>actual &&
 	cat >expect <<EOF &&
diff --git a/t/t5001-archive-attr.sh b/t/t5001-archive-attr.sh
index 712ae52..2f6eef5 100755
--- a/t/t5001-archive-attr.sh
+++ b/t/t5001-archive-attr.sh
@@ -2,6 +2,7 @@
 
 test_description='git archive attribute tests'
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 SUBSTFORMAT='%H (%h)%n'
@@ -20,6 +21,7 @@
 
 test_expect_success 'setup' '
 	echo ignored >ignored &&
+	mkdir .git/info &&
 	echo ignored export-ignore >>.git/info/attributes &&
 	git add ignored &&
 
@@ -46,7 +48,8 @@
 
 	git commit -m. &&
 
-	git clone --bare . bare &&
+	git clone --template= --bare . bare &&
+	mkdir bare/info &&
 	cp .git/info/attributes bare/info/attributes
 '
 
diff --git a/t/t5002-archive-attr-pattern.sh b/t/t5002-archive-attr-pattern.sh
index a66b5ba..78ab75f 100755
--- a/t/t5002-archive-attr-pattern.sh
+++ b/t/t5002-archive-attr-pattern.sh
@@ -3,6 +3,7 @@
 test_description='git archive attribute pattern tests'
 
 TEST_PASSES_SANITIZE_LEAK=true
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 test_expect_exists() {
@@ -15,6 +16,7 @@
 
 test_expect_success 'setup' '
 	echo ignored >ignored &&
+	mkdir .git/info &&
 	echo ignored export-ignore >>.git/info/attributes &&
 	git add ignored &&
 
@@ -54,7 +56,8 @@
 
 	git commit -m. &&
 
-	git clone --bare . bare &&
+	git clone --template= --bare . bare &&
+	mkdir bare/info &&
 	cp .git/info/attributes bare/info/attributes
 '
 
diff --git a/t/t5003-archive-zip.sh b/t/t5003-archive-zip.sh
index 3992d08..fc499cd 100755
--- a/t/t5003-archive-zip.sh
+++ b/t/t5003-archive-zip.sh
@@ -2,6 +2,7 @@
 
 test_description='git archive --format=zip test'
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 SUBSTFORMAT=%H%n
@@ -121,6 +122,7 @@
 test_expect_success \
     'add ignored file' \
     'echo ignore me >a/ignored &&
+     mkdir .git/info &&
      echo ignored export-ignore >.git/info/attributes'
 
 test_expect_success 'add files to repository' '
@@ -139,7 +141,8 @@
 '
 
 test_expect_success 'create bare clone' '
-	git clone --bare . bare.git &&
+	git clone --template= --bare . bare.git &&
+	mkdir bare.git/info &&
 	cp .git/info/attributes bare.git/info/attributes &&
 	# Recreate our changes to .git/config rather than just copying it, as
 	# we do not want to clobber core.bare or other settings.
diff --git a/t/t5303-pack-corruption-resilience.sh b/t/t5303-pack-corruption-resilience.sh
index 41e6dc4..2926e8d 100755
--- a/t/t5303-pack-corruption-resilience.sh
+++ b/t/t5303-pack-corruption-resilience.sh
@@ -4,6 +4,8 @@
 #
 
 test_description='resilience to pack corruptions with redundant objects'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # Note: the test objects are created with knowledge of their pack encoding
diff --git a/t/t5308-pack-detect-duplicates.sh b/t/t5308-pack-detect-duplicates.sh
index 693b241..655cafa 100755
--- a/t/t5308-pack-detect-duplicates.sh
+++ b/t/t5308-pack-detect-duplicates.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='handling of duplicate objects in incoming packfiles'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-pack.sh
 
diff --git a/t/t5309-pack-delta-cycles.sh b/t/t5309-pack-delta-cycles.sh
index 55b7876..4e910c5 100755
--- a/t/t5309-pack-delta-cycles.sh
+++ b/t/t5309-pack-delta-cycles.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test index-pack handling of delta cycles in packfiles'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-pack.sh
 
diff --git a/t/t5310-pack-bitmaps.sh b/t/t5310-pack-bitmaps.sh
index f775fc1..7e50f8e 100755
--- a/t/t5310-pack-bitmaps.sh
+++ b/t/t5310-pack-bitmaps.sh
@@ -26,22 +26,415 @@
 	grep -Ff "$1" "$2"
 }
 
-setup_bitmap_history
+test_bitmap_cases () {
+	writeLookupTable=false
+	for i in "$@"
+	do
+		case "$i" in
+		"pack.writeBitmapLookupTable") writeLookupTable=true;;
+		esac
+	done
 
-test_expect_success 'setup writing bitmaps during repack' '
-	git config repack.writeBitmaps true
-'
+	test_expect_success 'setup test repository' '
+		rm -fr * .git &&
+		git init &&
+		git config pack.writeBitmapLookupTable '"$writeLookupTable"'
+	'
+	setup_bitmap_history
 
-test_expect_success 'full repack creates bitmaps' '
-	GIT_TRACE2_EVENT="$(pwd)/trace" \
+	test_expect_success 'setup writing bitmaps during repack' '
+		git config repack.writeBitmaps true
+	'
+
+	test_expect_success 'full repack creates bitmaps' '
+		GIT_TRACE2_EVENT="$(pwd)/trace" \
+			git repack -ad &&
+		ls .git/objects/pack/ | grep bitmap >output &&
+		test_line_count = 1 output &&
+		grep "\"key\":\"num_selected_commits\",\"value\":\"106\"" trace &&
+		grep "\"key\":\"num_maximal_commits\",\"value\":\"107\"" trace
+	'
+
+	basic_bitmap_tests
+
+	test_expect_success 'pack-objects respects --local (non-local loose)' '
+		git init --bare alt.git &&
+		echo $(pwd)/alt.git/objects >.git/objects/info/alternates &&
+		echo content1 >file1 &&
+		# non-local loose object which is not present in bitmapped pack
+		altblob=$(GIT_DIR=alt.git git hash-object -w file1) &&
+		# non-local loose object which is also present in bitmapped pack
+		git cat-file blob $blob | GIT_DIR=alt.git git hash-object -w --stdin &&
+		git add file1 &&
+		test_tick &&
+		git commit -m commit_file1 &&
+		echo HEAD | git pack-objects --local --stdout --revs >1.pack &&
+		git index-pack 1.pack &&
+		list_packed_objects 1.idx >1.objects &&
+		printf "%s\n" "$altblob" "$blob" >nonlocal-loose &&
+		! has_any nonlocal-loose 1.objects
+	'
+
+	test_expect_success 'pack-objects respects --honor-pack-keep (local non-bitmapped pack)' '
+		echo content2 >file2 &&
+		blob2=$(git hash-object -w file2) &&
+		git add file2 &&
+		test_tick &&
+		git commit -m commit_file2 &&
+		printf "%s\n" "$blob2" "$bitmaptip" >keepobjects &&
+		pack2=$(git pack-objects pack2 <keepobjects) &&
+		mv pack2-$pack2.* .git/objects/pack/ &&
+		>.git/objects/pack/pack2-$pack2.keep &&
+		rm $(objpath $blob2) &&
+		echo HEAD | git pack-objects --honor-pack-keep --stdout --revs >2a.pack &&
+		git index-pack 2a.pack &&
+		list_packed_objects 2a.idx >2a.objects &&
+		! has_any keepobjects 2a.objects
+	'
+
+	test_expect_success 'pack-objects respects --local (non-local pack)' '
+		mv .git/objects/pack/pack2-$pack2.* alt.git/objects/pack/ &&
+		echo HEAD | git pack-objects --local --stdout --revs >2b.pack &&
+		git index-pack 2b.pack &&
+		list_packed_objects 2b.idx >2b.objects &&
+		! has_any keepobjects 2b.objects
+	'
+
+	test_expect_success 'pack-objects respects --honor-pack-keep (local bitmapped pack)' '
+		ls .git/objects/pack/ | grep bitmap >output &&
+		test_line_count = 1 output &&
+		packbitmap=$(basename $(cat output) .bitmap) &&
+		list_packed_objects .git/objects/pack/$packbitmap.idx >packbitmap.objects &&
+		test_when_finished "rm -f .git/objects/pack/$packbitmap.keep" &&
+		>.git/objects/pack/$packbitmap.keep &&
+		echo HEAD | git pack-objects --honor-pack-keep --stdout --revs >3a.pack &&
+		git index-pack 3a.pack &&
+		list_packed_objects 3a.idx >3a.objects &&
+		! has_any packbitmap.objects 3a.objects
+	'
+
+	test_expect_success 'pack-objects respects --local (non-local bitmapped pack)' '
+		mv .git/objects/pack/$packbitmap.* alt.git/objects/pack/ &&
+		rm -f .git/objects/pack/multi-pack-index &&
+		test_when_finished "mv alt.git/objects/pack/$packbitmap.* .git/objects/pack/" &&
+		echo HEAD | git pack-objects --local --stdout --revs >3b.pack &&
+		git index-pack 3b.pack &&
+		list_packed_objects 3b.idx >3b.objects &&
+		! has_any packbitmap.objects 3b.objects
+	'
+
+	test_expect_success 'pack-objects to file can use bitmap' '
+		# make sure we still have 1 bitmap index from previous tests
+		ls .git/objects/pack/ | grep bitmap >output &&
+		test_line_count = 1 output &&
+		# verify equivalent packs are generated with/without using bitmap index
+		packasha1=$(git pack-objects --no-use-bitmap-index --all packa </dev/null) &&
+		packbsha1=$(git pack-objects --use-bitmap-index --all packb </dev/null) &&
+		list_packed_objects packa-$packasha1.idx >packa.objects &&
+		list_packed_objects packb-$packbsha1.idx >packb.objects &&
+		test_cmp packa.objects packb.objects
+	'
+
+	test_expect_success 'full repack, reusing previous bitmaps' '
 		git repack -ad &&
-	ls .git/objects/pack/ | grep bitmap >output &&
-	test_line_count = 1 output &&
-	grep "\"key\":\"num_selected_commits\",\"value\":\"106\"" trace &&
-	grep "\"key\":\"num_maximal_commits\",\"value\":\"107\"" trace
-'
+		ls .git/objects/pack/ | grep bitmap >output &&
+		test_line_count = 1 output
+	'
 
-basic_bitmap_tests
+	test_expect_success 'fetch (full bitmap)' '
+		git --git-dir=clone.git fetch origin second:second &&
+		git rev-parse HEAD >expect &&
+		git --git-dir=clone.git rev-parse HEAD >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success 'create objects for missing-HAVE tests' '
+		blob=$(echo "missing have" | git hash-object -w --stdin) &&
+		tree=$(printf "100644 blob $blob\tfile\n" | git mktree) &&
+		parent=$(echo parent | git commit-tree $tree) &&
+		commit=$(echo commit | git commit-tree $tree -p $parent) &&
+		cat >revs <<-EOF
+		HEAD
+		^HEAD^
+		^$commit
+		EOF
+	'
+
+	test_expect_success 'pack-objects respects --incremental' '
+		cat >revs2 <<-EOF &&
+		HEAD
+		$commit
+		EOF
+		git pack-objects --incremental --stdout --revs <revs2 >4.pack &&
+		git index-pack 4.pack &&
+		list_packed_objects 4.idx >4.objects &&
+		test_line_count = 4 4.objects &&
+		git rev-list --objects $commit >revlist &&
+		cut -d" " -f1 revlist |sort >objects &&
+		test_cmp 4.objects objects
+	'
+
+	test_expect_success 'pack with missing blob' '
+		rm $(objpath $blob) &&
+		git pack-objects --stdout --revs <revs >/dev/null
+	'
+
+	test_expect_success 'pack with missing tree' '
+		rm $(objpath $tree) &&
+		git pack-objects --stdout --revs <revs >/dev/null
+	'
+
+	test_expect_success 'pack with missing parent' '
+		rm $(objpath $parent) &&
+		git pack-objects --stdout --revs <revs >/dev/null
+	'
+
+	test_expect_success JGIT,SHA1 'we can read jgit bitmaps' '
+		git clone --bare . compat-jgit.git &&
+		(
+			cd compat-jgit.git &&
+			rm -f objects/pack/*.bitmap &&
+			jgit gc &&
+			git rev-list --test-bitmap HEAD
+		)
+	'
+
+	test_expect_success JGIT,SHA1 'jgit can read our bitmaps' '
+		git clone --bare . compat-us.git &&
+		(
+			cd compat-us.git &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+			git repack -adb &&
+			# jgit gc will barf if it does not like our bitmaps
+			jgit gc
+		)
+	'
+
+	test_expect_success 'splitting packs does not generate bogus bitmaps' '
+		test-tool genrandom foo $((1024 * 1024)) >rand &&
+		git add rand &&
+		git commit -m "commit with big file" &&
+		git -c pack.packSizeLimit=500k repack -adb &&
+		git init --bare no-bitmaps.git &&
+		git -C no-bitmaps.git fetch .. HEAD
+	'
+
+	test_expect_success 'set up reusable pack' '
+		rm -f .git/objects/pack/*.keep &&
+		git repack -adb &&
+		reusable_pack () {
+			git for-each-ref --format="%(objectname)" |
+			git pack-objects --delta-base-offset --revs --stdout "$@"
+		}
+	'
+
+	test_expect_success 'pack reuse respects --honor-pack-keep' '
+		test_when_finished "rm -f .git/objects/pack/*.keep" &&
+		for i in .git/objects/pack/*.pack
+		do
+			>${i%.pack}.keep || return 1
+		done &&
+		reusable_pack --honor-pack-keep >empty.pack &&
+		git index-pack empty.pack &&
+		git show-index <empty.idx >actual &&
+		test_must_be_empty actual
+	'
+
+	test_expect_success 'pack reuse respects --local' '
+		mv .git/objects/pack/* alt.git/objects/pack/ &&
+		test_when_finished "mv alt.git/objects/pack/* .git/objects/pack/" &&
+		reusable_pack --local >empty.pack &&
+		git index-pack empty.pack &&
+		git show-index <empty.idx >actual &&
+		test_must_be_empty actual
+	'
+
+	test_expect_success 'pack reuse respects --incremental' '
+		reusable_pack --incremental >empty.pack &&
+		git index-pack empty.pack &&
+		git show-index <empty.idx >actual &&
+		test_must_be_empty actual
+	'
+
+	test_expect_success 'truncated bitmap fails gracefully (ewah)' '
+		test_config pack.writebitmaphashcache false &&
+		test_config pack.writebitmaplookuptable false &&
+		git repack -ad &&
+		git rev-list --use-bitmap-index --count --all >expect &&
+		bitmap=$(ls .git/objects/pack/*.bitmap) &&
+		test_when_finished "rm -f $bitmap" &&
+		test_copy_bytes 256 <$bitmap >$bitmap.tmp &&
+		mv -f $bitmap.tmp $bitmap &&
+		git rev-list --use-bitmap-index --count --all >actual 2>stderr &&
+		test_cmp expect actual &&
+		test_i18ngrep corrupt.ewah.bitmap stderr
+	'
+
+	test_expect_success 'truncated bitmap fails gracefully (cache)' '
+		git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+		git repack -ad &&
+		git rev-list --use-bitmap-index --count --all >expect &&
+		bitmap=$(ls .git/objects/pack/*.bitmap) &&
+		test_when_finished "rm -f $bitmap" &&
+		test_copy_bytes 512 <$bitmap >$bitmap.tmp &&
+		mv -f $bitmap.tmp $bitmap &&
+		git rev-list --use-bitmap-index --count --all >actual 2>stderr &&
+		test_cmp expect actual &&
+		test_i18ngrep corrupted.bitmap.index stderr
+	'
+
+	# Create a state of history with these properties:
+	#
+	#  - refs that allow a client to fetch some new history, while sharing some old
+	#    history with the server; we use branches delta-reuse-old and
+	#    delta-reuse-new here
+	#
+	#  - the new history contains an object that is stored on the server as a delta
+	#    against a base that is in the old history
+	#
+	#  - the base object is not immediately reachable from the tip of the old
+	#    history; finding it would involve digging down through history we know the
+	#    other side has
+	#
+	# This should result in a state where fetching from old->new would not
+	# traditionally reuse the on-disk delta (because we'd have to dig to realize
+	# that the client has it), but we will do so if bitmaps can tell us cheaply
+	# that the other side has it.
+	test_expect_success 'set up thin delta-reuse parent' '
+		# This first commit contains the buried base object.
+		test-tool genrandom delta 16384 >file &&
+		git add file &&
+		git commit -m "delta base" &&
+		base=$(git rev-parse --verify HEAD:file) &&
+
+		# These intermediate commits bury the base back in history.
+		# This becomes the "old" state.
+		for i in 1 2 3 4 5
+		do
+			echo $i >file &&
+			git commit -am "intermediate $i" || return 1
+		done &&
+		git branch delta-reuse-old &&
+
+		# And now our new history has a delta against the buried base. Note
+		# that this must be smaller than the original file, since pack-objects
+		# prefers to create deltas from smaller objects to larger.
+		test-tool genrandom delta 16300 >file &&
+		git commit -am "delta result" &&
+		delta=$(git rev-parse --verify HEAD:file) &&
+		git branch delta-reuse-new &&
+
+		# Repack with bitmaps and double check that we have the expected delta
+		# relationship.
+		git repack -adb &&
+		have_delta $delta $base
+	'
+
+	# Now we can sanity-check the non-bitmap behavior (that the server is not able
+	# to reuse the delta). This isn't strictly something we care about, so this
+	# test could be scrapped in the future. But it makes sure that the next test is
+	# actually triggering the feature we want.
+	#
+	# Note that our tools for working with on-the-wire "thin" packs are limited. So
+	# we actually perform the fetch, retain the resulting pack, and inspect the
+	# result.
+	test_expect_success 'fetch without bitmaps ignores delta against old base' '
+		test_config pack.usebitmaps false &&
+		test_when_finished "rm -rf client.git" &&
+		git init --bare client.git &&
+		(
+			cd client.git &&
+			git config transfer.unpackLimit 1 &&
+			git fetch .. delta-reuse-old:delta-reuse-old &&
+			git fetch .. delta-reuse-new:delta-reuse-new &&
+			have_delta $delta $ZERO_OID
+		)
+	'
+
+	# And do the same for the bitmap case, where we do expect to find the delta.
+	test_expect_success 'fetch with bitmaps can reuse old base' '
+		test_config pack.usebitmaps true &&
+		test_when_finished "rm -rf client.git" &&
+		git init --bare client.git &&
+		(
+			cd client.git &&
+			git config transfer.unpackLimit 1 &&
+			git fetch .. delta-reuse-old:delta-reuse-old &&
+			git fetch .. delta-reuse-new:delta-reuse-new &&
+			have_delta $delta $base
+		)
+	'
+
+	test_expect_success 'pack.preferBitmapTips' '
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			# create enough commits that not all are receive bitmap
+			# coverage even if they are all at the tip of some reference.
+			test_commit_bulk --message="%s" 103 &&
+
+			git rev-list HEAD >commits.raw &&
+			sort <commits.raw >commits &&
+
+			git log --format="create refs/tags/%s %H" HEAD >refs &&
+			git update-ref --stdin <refs &&
+
+			git repack -adb &&
+			test-tool bitmap list-commits | sort >bitmaps &&
+
+			# remember which commits did not receive bitmaps
+			comm -13 bitmaps commits >before &&
+			test_file_not_empty before &&
+
+			# mark the commits which did not receive bitmaps as preferred,
+			# and generate the bitmap again
+			perl -pe "s{^}{create refs/tags/include/$. }" <before |
+				git update-ref --stdin &&
+			git -c pack.preferBitmapTips=refs/tags/include repack -adb &&
+
+			# finally, check that the commit(s) without bitmap coverage
+			# are not the same ones as before
+			test-tool bitmap list-commits | sort >bitmaps &&
+			comm -13 bitmaps commits >after &&
+
+			! test_cmp before after
+		)
+	'
+
+	test_expect_success 'complains about multiple pack bitmaps' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			test_commit base &&
+
+			git repack -adb &&
+			bitmap="$(ls .git/objects/pack/pack-*.bitmap)" &&
+			mv "$bitmap" "$bitmap.bak" &&
+
+			test_commit other &&
+			git repack -ab &&
+
+			mv "$bitmap.bak" "$bitmap" &&
+
+			find .git/objects/pack -type f -name "*.pack" >packs &&
+			find .git/objects/pack -type f -name "*.bitmap" >bitmaps &&
+			test_line_count = 2 packs &&
+			test_line_count = 2 bitmaps &&
+
+			git rev-list --use-bitmap-index HEAD 2>err &&
+			grep "ignoring extra bitmap file" err
+		)
+	'
+}
+
+test_bitmap_cases
 
 test_expect_success 'incremental repack fails when bitmaps are requested' '
 	test_commit more-1 &&
@@ -54,219 +447,24 @@
 	git repack -d --no-write-bitmap-index
 '
 
-test_expect_success 'pack-objects respects --local (non-local loose)' '
-	git init --bare alt.git &&
-	echo $(pwd)/alt.git/objects >.git/objects/info/alternates &&
-	echo content1 >file1 &&
-	# non-local loose object which is not present in bitmapped pack
-	altblob=$(GIT_DIR=alt.git git hash-object -w file1) &&
-	# non-local loose object which is also present in bitmapped pack
-	git cat-file blob $blob | GIT_DIR=alt.git git hash-object -w --stdin &&
-	git add file1 &&
-	test_tick &&
-	git commit -m commit_file1 &&
-	echo HEAD | git pack-objects --local --stdout --revs >1.pack &&
-	git index-pack 1.pack &&
-	list_packed_objects 1.idx >1.objects &&
-	printf "%s\n" "$altblob" "$blob" >nonlocal-loose &&
-	! has_any nonlocal-loose 1.objects
+test_bitmap_cases "pack.writeBitmapLookupTable"
+
+test_expect_success 'verify writing bitmap lookup table when enabled' '
+	GIT_TRACE2_EVENT="$(pwd)/trace2" \
+		git repack -ad &&
+	grep "\"label\":\"writing_lookup_table\"" trace2
 '
 
-test_expect_success 'pack-objects respects --honor-pack-keep (local non-bitmapped pack)' '
-	echo content2 >file2 &&
-	blob2=$(git hash-object -w file2) &&
-	git add file2 &&
-	test_tick &&
-	git commit -m commit_file2 &&
-	printf "%s\n" "$blob2" "$bitmaptip" >keepobjects &&
-	pack2=$(git pack-objects pack2 <keepobjects) &&
-	mv pack2-$pack2.* .git/objects/pack/ &&
-	>.git/objects/pack/pack2-$pack2.keep &&
-	rm $(objpath $blob2) &&
-	echo HEAD | git pack-objects --honor-pack-keep --stdout --revs >2a.pack &&
-	git index-pack 2a.pack &&
-	list_packed_objects 2a.idx >2a.objects &&
-	! has_any keepobjects 2a.objects
-'
-
-test_expect_success 'pack-objects respects --local (non-local pack)' '
-	mv .git/objects/pack/pack2-$pack2.* alt.git/objects/pack/ &&
-	echo HEAD | git pack-objects --local --stdout --revs >2b.pack &&
-	git index-pack 2b.pack &&
-	list_packed_objects 2b.idx >2b.objects &&
-	! has_any keepobjects 2b.objects
-'
-
-test_expect_success 'pack-objects respects --honor-pack-keep (local bitmapped pack)' '
-	ls .git/objects/pack/ | grep bitmap >output &&
-	test_line_count = 1 output &&
-	packbitmap=$(basename $(cat output) .bitmap) &&
-	list_packed_objects .git/objects/pack/$packbitmap.idx >packbitmap.objects &&
-	test_when_finished "rm -f .git/objects/pack/$packbitmap.keep" &&
-	>.git/objects/pack/$packbitmap.keep &&
-	echo HEAD | git pack-objects --honor-pack-keep --stdout --revs >3a.pack &&
-	git index-pack 3a.pack &&
-	list_packed_objects 3a.idx >3a.objects &&
-	! has_any packbitmap.objects 3a.objects
-'
-
-test_expect_success 'pack-objects respects --local (non-local bitmapped pack)' '
-	mv .git/objects/pack/$packbitmap.* alt.git/objects/pack/ &&
-	rm -f .git/objects/pack/multi-pack-index &&
-	test_when_finished "mv alt.git/objects/pack/$packbitmap.* .git/objects/pack/" &&
-	echo HEAD | git pack-objects --local --stdout --revs >3b.pack &&
-	git index-pack 3b.pack &&
-	list_packed_objects 3b.idx >3b.objects &&
-	! has_any packbitmap.objects 3b.objects
-'
-
-test_expect_success 'pack-objects to file can use bitmap' '
-	# make sure we still have 1 bitmap index from previous tests
-	ls .git/objects/pack/ | grep bitmap >output &&
-	test_line_count = 1 output &&
-	# verify equivalent packs are generated with/without using bitmap index
-	packasha1=$(git pack-objects --no-use-bitmap-index --all packa </dev/null) &&
-	packbsha1=$(git pack-objects --use-bitmap-index --all packb </dev/null) &&
-	list_packed_objects packa-$packasha1.idx >packa.objects &&
-	list_packed_objects packb-$packbsha1.idx >packb.objects &&
-	test_cmp packa.objects packb.objects
-'
-
-test_expect_success 'full repack, reusing previous bitmaps' '
-	git repack -ad &&
-	ls .git/objects/pack/ | grep bitmap >output &&
-	test_line_count = 1 output
-'
-
-test_expect_success 'fetch (full bitmap)' '
-	git --git-dir=clone.git fetch origin second:second &&
-	git rev-parse HEAD >expect &&
-	git --git-dir=clone.git rev-parse HEAD >actual &&
-	test_cmp expect actual
-'
-
-test_expect_success 'create objects for missing-HAVE tests' '
-	blob=$(echo "missing have" | git hash-object -w --stdin) &&
-	tree=$(printf "100644 blob $blob\tfile\n" | git mktree) &&
-	parent=$(echo parent | git commit-tree $tree) &&
-	commit=$(echo commit | git commit-tree $tree -p $parent) &&
-	cat >revs <<-EOF
-	HEAD
-	^HEAD^
-	^$commit
-	EOF
-'
-
-test_expect_success 'pack-objects respects --incremental' '
-	cat >revs2 <<-EOF &&
-	HEAD
-	$commit
-	EOF
-	git pack-objects --incremental --stdout --revs <revs2 >4.pack &&
-	git index-pack 4.pack &&
-	list_packed_objects 4.idx >4.objects &&
-	test_line_count = 4 4.objects &&
-	git rev-list --objects $commit >revlist &&
-	cut -d" " -f1 revlist |sort >objects &&
-	test_cmp 4.objects objects
-'
-
-test_expect_success 'pack with missing blob' '
-	rm $(objpath $blob) &&
-	git pack-objects --stdout --revs <revs >/dev/null
-'
-
-test_expect_success 'pack with missing tree' '
-	rm $(objpath $tree) &&
-	git pack-objects --stdout --revs <revs >/dev/null
-'
-
-test_expect_success 'pack with missing parent' '
-	rm $(objpath $parent) &&
-	git pack-objects --stdout --revs <revs >/dev/null
-'
-
-test_expect_success JGIT,SHA1 'we can read jgit bitmaps' '
-	git clone --bare . compat-jgit.git &&
-	(
-		cd compat-jgit.git &&
-		rm -f objects/pack/*.bitmap &&
-		jgit gc &&
-		git rev-list --test-bitmap HEAD
-	)
-'
-
-test_expect_success JGIT,SHA1 'jgit can read our bitmaps' '
-	git clone --bare . compat-us.git &&
-	(
-		cd compat-us.git &&
-		git repack -adb &&
-		# jgit gc will barf if it does not like our bitmaps
-		jgit gc
-	)
-'
-
-test_expect_success 'splitting packs does not generate bogus bitmaps' '
-	test-tool genrandom foo $((1024 * 1024)) >rand &&
-	git add rand &&
-	git commit -m "commit with big file" &&
-	git -c pack.packSizeLimit=500k repack -adb &&
-	git init --bare no-bitmaps.git &&
-	git -C no-bitmaps.git fetch .. HEAD
-'
-
-test_expect_success 'set up reusable pack' '
-	rm -f .git/objects/pack/*.keep &&
+test_expect_success 'lookup table is actually used to traverse objects' '
 	git repack -adb &&
-	reusable_pack () {
-		git for-each-ref --format="%(objectname)" |
-		git pack-objects --delta-base-offset --revs --stdout "$@"
-	}
+	GIT_TRACE2_EVENT="$(pwd)/trace3" \
+		git rev-list --use-bitmap-index --count --all &&
+	grep "\"label\":\"reading_lookup_table\"" trace3
 '
 
-test_expect_success 'pack reuse respects --honor-pack-keep' '
-	test_when_finished "rm -f .git/objects/pack/*.keep" &&
-	for i in .git/objects/pack/*.pack
-	do
-		>${i%.pack}.keep || return 1
-	done &&
-	reusable_pack --honor-pack-keep >empty.pack &&
-	git index-pack empty.pack &&
-	git show-index <empty.idx >actual &&
-	test_must_be_empty actual
-'
-
-test_expect_success 'pack reuse respects --local' '
-	mv .git/objects/pack/* alt.git/objects/pack/ &&
-	test_when_finished "mv alt.git/objects/pack/* .git/objects/pack/" &&
-	reusable_pack --local >empty.pack &&
-	git index-pack empty.pack &&
-	git show-index <empty.idx >actual &&
-	test_must_be_empty actual
-'
-
-test_expect_success 'pack reuse respects --incremental' '
-	reusable_pack --incremental >empty.pack &&
-	git index-pack empty.pack &&
-	git show-index <empty.idx >actual &&
-	test_must_be_empty actual
-'
-
-test_expect_success 'truncated bitmap fails gracefully (ewah)' '
+test_expect_success 'truncated bitmap fails gracefully (lookup table)' '
 	test_config pack.writebitmaphashcache false &&
-	git repack -ad &&
-	git rev-list --use-bitmap-index --count --all >expect &&
-	bitmap=$(ls .git/objects/pack/*.bitmap) &&
-	test_when_finished "rm -f $bitmap" &&
-	test_copy_bytes 256 <$bitmap >$bitmap.tmp &&
-	mv -f $bitmap.tmp $bitmap &&
-	git rev-list --use-bitmap-index --count --all >actual 2>stderr &&
-	test_cmp expect actual &&
-	test_i18ngrep corrupt.ewah.bitmap stderr
-'
-
-test_expect_success 'truncated bitmap fails gracefully (cache)' '
-	git repack -ad &&
+	git repack -adb &&
 	git rev-list --use-bitmap-index --count --all >expect &&
 	bitmap=$(ls .git/objects/pack/*.bitmap) &&
 	test_when_finished "rm -f $bitmap" &&
@@ -277,152 +475,4 @@
 	test_i18ngrep corrupted.bitmap.index stderr
 '
 
-# Create a state of history with these properties:
-#
-#  - refs that allow a client to fetch some new history, while sharing some old
-#    history with the server; we use branches delta-reuse-old and
-#    delta-reuse-new here
-#
-#  - the new history contains an object that is stored on the server as a delta
-#    against a base that is in the old history
-#
-#  - the base object is not immediately reachable from the tip of the old
-#    history; finding it would involve digging down through history we know the
-#    other side has
-#
-# This should result in a state where fetching from old->new would not
-# traditionally reuse the on-disk delta (because we'd have to dig to realize
-# that the client has it), but we will do so if bitmaps can tell us cheaply
-# that the other side has it.
-test_expect_success 'set up thin delta-reuse parent' '
-	# This first commit contains the buried base object.
-	test-tool genrandom delta 16384 >file &&
-	git add file &&
-	git commit -m "delta base" &&
-	base=$(git rev-parse --verify HEAD:file) &&
-
-	# These intermediate commits bury the base back in history.
-	# This becomes the "old" state.
-	for i in 1 2 3 4 5
-	do
-		echo $i >file &&
-		git commit -am "intermediate $i" || return 1
-	done &&
-	git branch delta-reuse-old &&
-
-	# And now our new history has a delta against the buried base. Note
-	# that this must be smaller than the original file, since pack-objects
-	# prefers to create deltas from smaller objects to larger.
-	test-tool genrandom delta 16300 >file &&
-	git commit -am "delta result" &&
-	delta=$(git rev-parse --verify HEAD:file) &&
-	git branch delta-reuse-new &&
-
-	# Repack with bitmaps and double check that we have the expected delta
-	# relationship.
-	git repack -adb &&
-	have_delta $delta $base
-'
-
-# Now we can sanity-check the non-bitmap behavior (that the server is not able
-# to reuse the delta). This isn't strictly something we care about, so this
-# test could be scrapped in the future. But it makes sure that the next test is
-# actually triggering the feature we want.
-#
-# Note that our tools for working with on-the-wire "thin" packs are limited. So
-# we actually perform the fetch, retain the resulting pack, and inspect the
-# result.
-test_expect_success 'fetch without bitmaps ignores delta against old base' '
-	test_config pack.usebitmaps false &&
-	test_when_finished "rm -rf client.git" &&
-	git init --bare client.git &&
-	(
-		cd client.git &&
-		git config transfer.unpackLimit 1 &&
-		git fetch .. delta-reuse-old:delta-reuse-old &&
-		git fetch .. delta-reuse-new:delta-reuse-new &&
-		have_delta $delta $ZERO_OID
-	)
-'
-
-# And do the same for the bitmap case, where we do expect to find the delta.
-test_expect_success 'fetch with bitmaps can reuse old base' '
-	test_config pack.usebitmaps true &&
-	test_when_finished "rm -rf client.git" &&
-	git init --bare client.git &&
-	(
-		cd client.git &&
-		git config transfer.unpackLimit 1 &&
-		git fetch .. delta-reuse-old:delta-reuse-old &&
-		git fetch .. delta-reuse-new:delta-reuse-new &&
-		have_delta $delta $base
-	)
-'
-
-test_expect_success 'pack.preferBitmapTips' '
-	git init repo &&
-	test_when_finished "rm -fr repo" &&
-	(
-		cd repo &&
-
-		# create enough commits that not all are receive bitmap
-		# coverage even if they are all at the tip of some reference.
-		test_commit_bulk --message="%s" 103 &&
-
-		git rev-list HEAD >commits.raw &&
-		sort <commits.raw >commits &&
-
-		git log --format="create refs/tags/%s %H" HEAD >refs &&
-		git update-ref --stdin <refs &&
-
-		git repack -adb &&
-		test-tool bitmap list-commits | sort >bitmaps &&
-
-		# remember which commits did not receive bitmaps
-		comm -13 bitmaps commits >before &&
-		test_file_not_empty before &&
-
-		# mark the commits which did not receive bitmaps as preferred,
-		# and generate the bitmap again
-		perl -pe "s{^}{create refs/tags/include/$. }" <before |
-			git update-ref --stdin &&
-		git -c pack.preferBitmapTips=refs/tags/include repack -adb &&
-
-		# finally, check that the commit(s) without bitmap coverage
-		# are not the same ones as before
-		test-tool bitmap list-commits | sort >bitmaps &&
-		comm -13 bitmaps commits >after &&
-
-		! test_cmp before after
-	)
-'
-
-test_expect_success 'complains about multiple pack bitmaps' '
-	rm -fr repo &&
-	git init repo &&
-	test_when_finished "rm -fr repo" &&
-	(
-		cd repo &&
-
-		test_commit base &&
-
-		git repack -adb &&
-		bitmap="$(ls .git/objects/pack/pack-*.bitmap)" &&
-		mv "$bitmap" "$bitmap.bak" &&
-
-		test_commit other &&
-		git repack -ab &&
-
-		mv "$bitmap.bak" "$bitmap" &&
-
-		find .git/objects/pack -type f -name "*.pack" >packs &&
-		find .git/objects/pack -type f -name "*.bitmap" >bitmaps &&
-		test_line_count = 2 packs &&
-		test_line_count = 2 bitmaps &&
-
-		git rev-list --use-bitmap-index HEAD 2>err &&
-		grep "ignoring extra bitmap file" err
-	)
-'
-
 test_done
diff --git a/t/t5311-pack-bitmaps-shallow.sh b/t/t5311-pack-bitmaps-shallow.sh
index 872a95d..9dae60f 100755
--- a/t/t5311-pack-bitmaps-shallow.sh
+++ b/t/t5311-pack-bitmaps-shallow.sh
@@ -17,23 +17,40 @@
 # the tree for A. But in a shallow one, we've grafted away
 # A, and fetching A to B requires that the other side send
 # us the tree for file=1.
-test_expect_success 'setup shallow repo' '
-	echo 1 >file &&
-	git add file &&
-	git commit -m orig &&
-	echo 2 >file &&
-	git commit -a -m update &&
-	git clone --no-local --bare --depth=1 . shallow.git &&
-	echo 1 >file &&
-	git commit -a -m repeat
-'
+test_shallow_bitmaps () {
+	writeLookupTable=false
 
-test_expect_success 'turn on bitmaps in the parent' '
-	git repack -adb
-'
+	for i in "$@"
+	do
+		case $i in
+		"pack.writeBitmapLookupTable") writeLookupTable=true;;
+		esac
+	done
 
-test_expect_success 'shallow fetch from bitmapped repo' '
-	(cd shallow.git && git fetch)
-'
+	test_expect_success 'setup shallow repo' '
+		rm -rf * .git &&
+		git init &&
+		git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+		echo 1 >file &&
+		git add file &&
+		git commit -m orig &&
+		echo 2 >file &&
+		git commit -a -m update &&
+		git clone --no-local --bare --depth=1 . shallow.git &&
+		echo 1 >file &&
+		git commit -a -m repeat
+	'
+
+	test_expect_success 'turn on bitmaps in the parent' '
+		git repack -adb
+	'
+
+	test_expect_success 'shallow fetch from bitmapped repo' '
+		(cd shallow.git && git fetch)
+	'
+}
+
+test_shallow_bitmaps
+test_shallow_bitmaps "pack.writeBitmapLookupTable"
 
 test_done
diff --git a/t/t5314-pack-cycle-detection.sh b/t/t5314-pack-cycle-detection.sh
index 0aec861..73a2417 100755
--- a/t/t5314-pack-cycle-detection.sh
+++ b/t/t5314-pack-cycle-detection.sh
@@ -49,10 +49,10 @@
 will always find a delta for "file", because its lookup will always come
 immediately after the lookup for "dummy".
 '
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
-
-
 # Create a pack containing the tree $1 and blob $1:file, with
 # the latter stored as a delta against $2:file.
 #
diff --git a/t/t5315-pack-objects-compression.sh b/t/t5315-pack-objects-compression.sh
index 8bacd96..c80ea9e 100755
--- a/t/t5315-pack-objects-compression.sh
+++ b/t/t5315-pack-objects-compression.sh
@@ -2,6 +2,7 @@
 
 test_description='pack-object compression configuration'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index db89542..049c5fc 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -12,12 +12,12 @@
 
 test_expect_success 'usage shown without sub-command' '
 	test_expect_code 129 git commit-graph 2>err &&
-	! grep error: err
+	grep usage: err
 '
 
 test_expect_success 'usage shown with an error on unknown sub-command' '
 	cat >expect <<-\EOF &&
-	error: unrecognized subcommand: unknown
+	error: unknown subcommand: `unknown'\''
 	EOF
 	test_expect_code 129 git commit-graph unknown 2>stderr &&
 	grep error stderr >actual &&
@@ -361,13 +361,14 @@
 test_expect_success 'commit grafts invalidate commit-graph' '
 	cd "$TRASH_DIRECTORY" &&
 	test_when_finished rm -rf graft &&
-	git clone full graft &&
+	git clone --template= full graft &&
 	(
 		cd graft &&
 		git commit-graph write --reachable &&
 		test_path_is_file .git/objects/info/commit-graph &&
 		H1=$(git rev-parse --verify HEAD~1) &&
 		H3=$(git rev-parse --verify HEAD~3) &&
+		mkdir .git/info &&
 		echo "$H1 $H3" >.git/info/grafts &&
 		git -c core.commitGraph=false log >expect &&
 		git -c core.commitGraph=true log >actual &&
diff --git a/t/t5321-pack-large-objects.sh b/t/t5321-pack-large-objects.sh
index 8a56d98..70770fe 100755
--- a/t/t5321-pack-large-objects.sh
+++ b/t/t5321-pack-large-objects.sh
@@ -6,6 +6,8 @@
 test_description='git pack-object with "large" deltas
 
 '
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-pack.sh
 
diff --git a/t/t5326-multi-pack-bitmaps.sh b/t/t5326-multi-pack-bitmaps.sh
index 4fe5741..ad6eea5 100755
--- a/t/t5326-multi-pack-bitmaps.sh
+++ b/t/t5326-multi-pack-bitmaps.sh
@@ -15,17 +15,24 @@
 sane_unset GIT_TEST_MIDX_WRITE_REV
 sane_unset GIT_TEST_MIDX_READ_RIDX
 
-midx_bitmap_core
-
 bitmap_reuse_tests() {
 	from=$1
 	to=$2
+	writeLookupTable=false
+
+	for i in $3-${$#}
+	do
+		case $i in
+		"pack.writeBitmapLookupTable") writeLookupTable=true;;
+		esac
+	done
 
 	test_expect_success "setup pack reuse tests ($from -> $to)" '
 		rm -fr repo &&
 		git init repo &&
 		(
 			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
 			test_commit_bulk 16 &&
 			git tag old-tip &&
 
@@ -43,6 +50,7 @@
 	test_expect_success "build bitmap from existing ($from -> $to)" '
 		(
 			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
 			test_commit_bulk --id=further 16 &&
 			git tag new-tip &&
 
@@ -59,6 +67,7 @@
 	test_expect_success "verify resulting bitmaps ($from -> $to)" '
 		(
 			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
 			git for-each-ref &&
 			git rev-list --test-bitmap refs/tags/old-tip &&
 			git rev-list --test-bitmap refs/tags/new-tip
@@ -66,244 +75,338 @@
 	'
 }
 
-bitmap_reuse_tests 'pack' 'MIDX'
-bitmap_reuse_tests 'MIDX' 'pack'
-bitmap_reuse_tests 'MIDX' 'MIDX'
+test_midx_bitmap_cases () {
+	writeLookupTable=false
+	writeBitmapLookupTable=
 
-test_expect_success 'missing object closure fails gracefully' '
-	rm -fr repo &&
-	git init repo &&
-	test_when_finished "rm -fr repo" &&
-	(
-		cd repo &&
+	for i in "$@"
+	do
+		case $i in
+		"pack.writeBitmapLookupTable")
+			writeLookupTable=true
+			writeBitmapLookupTable="$i"
+			;;
+		esac
+	done
 
-		test_commit loose &&
-		test_commit packed &&
+	test_expect_success 'setup test_repository' '
+		rm -rf * .git &&
+		git init &&
+		git config pack.writeBitmapLookupTable '"$writeLookupTable"'
+	'
 
-		# Do not pass "--revs"; we want a pack without the "loose"
-		# commit.
-		git pack-objects $objdir/pack/pack <<-EOF &&
-		$(git rev-parse packed)
-		EOF
+	midx_bitmap_core
 
-		test_must_fail git multi-pack-index write --bitmap 2>err &&
-		grep "doesn.t have full closure" err &&
-		test_path_is_missing $midx
-	)
-'
+	bitmap_reuse_tests 'pack' 'MIDX' "$writeBitmapLookupTable"
+	bitmap_reuse_tests 'MIDX' 'pack' "$writeBitmapLookupTable"
+	bitmap_reuse_tests 'MIDX' 'MIDX' "$writeBitmapLookupTable"
 
-midx_bitmap_partial_tests
-
-test_expect_success 'removing a MIDX clears stale bitmaps' '
-	rm -fr repo &&
-	git init repo &&
-	test_when_finished "rm -fr repo" &&
-	(
-		cd repo &&
-		test_commit base &&
-		git repack &&
-		git multi-pack-index write --bitmap &&
-
-		# Write a MIDX and bitmap; remove the MIDX but leave the bitmap.
-		stale_bitmap=$midx-$(midx_checksum $objdir).bitmap &&
-		rm $midx &&
-
-		# Then write a new MIDX.
-		test_commit new &&
-		git repack &&
-		git multi-pack-index write --bitmap &&
-
-		test_path_is_file $midx &&
-		test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
-		test_path_is_missing $stale_bitmap
-	)
-'
-
-test_expect_success 'pack.preferBitmapTips' '
-	git init repo &&
-	test_when_finished "rm -fr repo" &&
-	(
-		cd repo &&
-
-		test_commit_bulk --message="%s" 103 &&
-
-		git log --format="%H" >commits.raw &&
-		sort <commits.raw >commits &&
-
-		git log --format="create refs/tags/%s %H" HEAD >refs &&
-		git update-ref --stdin <refs &&
-
-		git multi-pack-index write --bitmap &&
-		test_path_is_file $midx &&
-		test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
-
-		test-tool bitmap list-commits | sort >bitmaps &&
-		comm -13 bitmaps commits >before &&
-		test_line_count = 1 before &&
-
-		perl -ne "printf(\"create refs/tags/include/%d \", $.); print" \
-			<before | git update-ref --stdin &&
-
-		rm -fr $midx-$(midx_checksum $objdir).bitmap &&
-		rm -fr $midx &&
-
-		git -c pack.preferBitmapTips=refs/tags/include \
-			multi-pack-index write --bitmap &&
-		test-tool bitmap list-commits | sort >bitmaps &&
-		comm -13 bitmaps commits >after &&
-
-		! test_cmp before after
-	)
-'
-
-test_expect_success 'writing a bitmap with --refs-snapshot' '
-	git init repo &&
-	test_when_finished "rm -fr repo" &&
-	(
-		cd repo &&
-
-		test_commit one &&
-		test_commit two &&
-
-		git rev-parse one >snapshot &&
-
-		git repack -ad &&
-
-		# First, write a MIDX which see both refs/tags/one and
-		# refs/tags/two (causing both of those commits to receive
-		# bitmaps).
-		git multi-pack-index write --bitmap &&
-
-		test_path_is_file $midx &&
-		test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
-
-		test-tool bitmap list-commits | sort >bitmaps &&
-		grep "$(git rev-parse one)" bitmaps &&
-		grep "$(git rev-parse two)" bitmaps &&
-
-		rm -fr $midx-$(midx_checksum $objdir).bitmap &&
-		rm -fr $midx &&
-
-		# Then again, but with a refs snapshot which only sees
-		# refs/tags/one.
-		git multi-pack-index write --bitmap --refs-snapshot=snapshot &&
-
-		test_path_is_file $midx &&
-		test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
-
-		test-tool bitmap list-commits | sort >bitmaps &&
-		grep "$(git rev-parse one)" bitmaps &&
-		! grep "$(git rev-parse two)" bitmaps
-	)
-'
-
-test_expect_success 'write a bitmap with --refs-snapshot (preferred tips)' '
-	git init repo &&
-	test_when_finished "rm -fr repo" &&
-	(
-		cd repo &&
-
-		test_commit_bulk --message="%s" 103 &&
-
-		git log --format="%H" >commits.raw &&
-		sort <commits.raw >commits &&
-
-		git log --format="create refs/tags/%s %H" HEAD >refs &&
-		git update-ref --stdin <refs &&
-
-		git multi-pack-index write --bitmap &&
-		test_path_is_file $midx &&
-		test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
-
-		test-tool bitmap list-commits | sort >bitmaps &&
-		comm -13 bitmaps commits >before &&
-		test_line_count = 1 before &&
-
+	test_expect_success 'missing object closure fails gracefully' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
 		(
-			grep -vf before commits.raw &&
-			# mark missing commits as preferred
-			sed "s/^/+/" before
-		) >snapshot &&
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
 
-		rm -fr $midx-$(midx_checksum $objdir).bitmap &&
-		rm -fr $midx &&
+			test_commit loose &&
+			test_commit packed &&
 
-		git multi-pack-index write --bitmap --refs-snapshot=snapshot &&
-		test-tool bitmap list-commits | sort >bitmaps &&
-		comm -13 bitmaps commits >after &&
+			# Do not pass "--revs"; we want a pack without the "loose"
+			# commit.
+			git pack-objects $objdir/pack/pack <<-EOF &&
+			$(git rev-parse packed)
+			EOF
 
-		! test_cmp before after
-	)
-'
+			test_must_fail git multi-pack-index write --bitmap 2>err &&
+			grep "doesn.t have full closure" err &&
+			test_path_is_missing $midx
+		)
+	'
 
-test_expect_success 'hash-cache values are propagated from pack bitmaps' '
+	midx_bitmap_partial_tests
+
+	test_expect_success 'removing a MIDX clears stale bitmaps' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+			test_commit base &&
+			git repack &&
+			git multi-pack-index write --bitmap &&
+
+			# Write a MIDX and bitmap; remove the MIDX but leave the bitmap.
+			stale_bitmap=$midx-$(midx_checksum $objdir).bitmap &&
+			rm $midx &&
+
+			# Then write a new MIDX.
+			test_commit new &&
+			git repack &&
+			git multi-pack-index write --bitmap &&
+
+			test_path_is_file $midx &&
+			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+			test_path_is_missing $stale_bitmap
+		)
+	'
+
+	test_expect_success 'pack.preferBitmapTips' '
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			test_commit_bulk --message="%s" 103 &&
+
+			git log --format="%H" >commits.raw &&
+			sort <commits.raw >commits &&
+
+			git log --format="create refs/tags/%s %H" HEAD >refs &&
+			git update-ref --stdin <refs &&
+
+			git multi-pack-index write --bitmap &&
+			test_path_is_file $midx &&
+			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+
+			test-tool bitmap list-commits | sort >bitmaps &&
+			comm -13 bitmaps commits >before &&
+			test_line_count = 1 before &&
+
+			perl -ne "printf(\"create refs/tags/include/%d \", $.); print" \
+				<before | git update-ref --stdin &&
+
+			rm -fr $midx-$(midx_checksum $objdir).bitmap &&
+			rm -fr $midx &&
+
+			git -c pack.preferBitmapTips=refs/tags/include \
+				multi-pack-index write --bitmap &&
+			test-tool bitmap list-commits | sort >bitmaps &&
+			comm -13 bitmaps commits >after &&
+
+			! test_cmp before after
+		)
+	'
+
+	test_expect_success 'writing a bitmap with --refs-snapshot' '
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			test_commit one &&
+			test_commit two &&
+
+			git rev-parse one >snapshot &&
+
+			git repack -ad &&
+
+			# First, write a MIDX which see both refs/tags/one and
+			# refs/tags/two (causing both of those commits to receive
+			# bitmaps).
+			git multi-pack-index write --bitmap &&
+
+			test_path_is_file $midx &&
+			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+
+			test-tool bitmap list-commits | sort >bitmaps &&
+			grep "$(git rev-parse one)" bitmaps &&
+			grep "$(git rev-parse two)" bitmaps &&
+
+			rm -fr $midx-$(midx_checksum $objdir).bitmap &&
+			rm -fr $midx &&
+
+			# Then again, but with a refs snapshot which only sees
+			# refs/tags/one.
+			git multi-pack-index write --bitmap --refs-snapshot=snapshot &&
+
+			test_path_is_file $midx &&
+			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+
+			test-tool bitmap list-commits | sort >bitmaps &&
+			grep "$(git rev-parse one)" bitmaps &&
+			! grep "$(git rev-parse two)" bitmaps
+		)
+	'
+
+	test_expect_success 'write a bitmap with --refs-snapshot (preferred tips)' '
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			test_commit_bulk --message="%s" 103 &&
+
+			git log --format="%H" >commits.raw &&
+			sort <commits.raw >commits &&
+
+			git log --format="create refs/tags/%s %H" HEAD >refs &&
+			git update-ref --stdin <refs &&
+
+			git multi-pack-index write --bitmap &&
+			test_path_is_file $midx &&
+			test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+
+			test-tool bitmap list-commits | sort >bitmaps &&
+			comm -13 bitmaps commits >before &&
+			test_line_count = 1 before &&
+
+			(
+				grep -vf before commits.raw &&
+				# mark missing commits as preferred
+				sed "s/^/+/" before
+			) >snapshot &&
+
+			rm -fr $midx-$(midx_checksum $objdir).bitmap &&
+			rm -fr $midx &&
+
+			git multi-pack-index write --bitmap --refs-snapshot=snapshot &&
+			test-tool bitmap list-commits | sort >bitmaps &&
+			comm -13 bitmaps commits >after &&
+
+			! test_cmp before after
+		)
+	'
+
+	test_expect_success 'hash-cache values are propagated from pack bitmaps' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			test_commit base &&
+			test_commit base2 &&
+			git repack -adb &&
+
+			test-tool bitmap dump-hashes >pack.raw &&
+			test_file_not_empty pack.raw &&
+			sort pack.raw >pack.hashes &&
+
+			test_commit new &&
+			git repack &&
+			git multi-pack-index write --bitmap &&
+
+			test-tool bitmap dump-hashes >midx.raw &&
+			sort midx.raw >midx.hashes &&
+
+			# ensure that every namehash in the pack bitmap can be found in
+			# the midx bitmap (i.e., that there are no oid-namehash pairs
+			# unique to the pack bitmap).
+			comm -23 pack.hashes midx.hashes >dropped.hashes &&
+			test_must_be_empty dropped.hashes
+		)
+	'
+
+	test_expect_success 'no .bitmap is written without any objects' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			empty="$(git pack-objects $objdir/pack/pack </dev/null)" &&
+			cat >packs <<-EOF &&
+			pack-$empty.idx
+			EOF
+
+			git multi-pack-index write --bitmap --stdin-packs \
+				<packs 2>err &&
+
+			grep "bitmap without any objects" err &&
+
+			test_path_is_file $midx &&
+			test_path_is_missing $midx-$(midx_checksum $objdir).bitmap
+		)
+	'
+
+	test_expect_success 'graceful fallback when missing reverse index' '
+		rm -fr repo &&
+		git init repo &&
+		test_when_finished "rm -fr repo" &&
+		(
+			cd repo &&
+			git config pack.writeBitmapLookupTable '"$writeLookupTable"' &&
+
+			test_commit base &&
+
+			# write a pack and MIDX bitmap containing base
+			git repack -adb &&
+			git multi-pack-index write --bitmap &&
+
+			GIT_TEST_MIDX_READ_RIDX=0 \
+				git rev-list --use-bitmap-index HEAD 2>err &&
+			! grep "ignoring extra bitmap file" err
+		)
+	'
+}
+
+test_midx_bitmap_cases
+
+test_midx_bitmap_cases "pack.writeBitmapLookupTable"
+
+test_expect_success 'multi-pack-index write writes lookup table if enabled' '
 	rm -fr repo &&
 	git init repo &&
 	test_when_finished "rm -fr repo" &&
 	(
 		cd repo &&
+		test_commit base &&
+		git config pack.writeBitmapLookupTable true &&
+		git repack -ad &&
+		GIT_TRACE2_EVENT="$(pwd)/trace" \
+			git multi-pack-index write --bitmap &&
+		grep "\"label\":\"writing_lookup_table\"" trace
+	)
+'
+
+test_expect_success 'preferred pack change with existing MIDX bitmap' '
+	git init preferred-pack-with-existing &&
+	(
+		cd preferred-pack-with-existing &&
 
 		test_commit base &&
-		test_commit base2 &&
-		git repack -adb &&
+		test_commit other &&
 
-		test-tool bitmap dump-hashes >pack.raw &&
-		test_file_not_empty pack.raw &&
-		sort pack.raw >pack.hashes &&
+		git rev-list --objects --no-object-names base >p1.objects &&
+		git rev-list --objects --no-object-names other >p2.objects &&
 
-		test_commit new &&
-		git repack &&
-		git multi-pack-index write --bitmap &&
+		p1="$(git pack-objects "$objdir/pack/pack" \
+			--delta-base-offset <p1.objects)" &&
+		p2="$(git pack-objects "$objdir/pack/pack" \
+			--delta-base-offset <p2.objects)" &&
 
-		test-tool bitmap dump-hashes >midx.raw &&
-		sort midx.raw >midx.hashes &&
-
-		# ensure that every namehash in the pack bitmap can be found in
-		# the midx bitmap (i.e., that there are no oid-namehash pairs
-		# unique to the pack bitmap).
-		comm -23 pack.hashes midx.hashes >dropped.hashes &&
-		test_must_be_empty dropped.hashes
-	)
-'
-
-test_expect_success 'no .bitmap is written without any objects' '
-	rm -fr repo &&
-	git init repo &&
-	test_when_finished "rm -fr repo" &&
-	(
-		cd repo &&
-
-		empty="$(git pack-objects $objdir/pack/pack </dev/null)" &&
-		cat >packs <<-EOF &&
-		pack-$empty.idx
-		EOF
-
-		git multi-pack-index write --bitmap --stdin-packs \
-			<packs 2>err &&
-
-		grep "bitmap without any objects" err &&
-
+		# Generate a MIDX containing the first two packs,
+		# marking p1 as preferred, and ensure that it can be
+		# successfully cloned.
+		git multi-pack-index write --bitmap \
+			--preferred-pack="pack-$p1.pack" &&
 		test_path_is_file $midx &&
-		test_path_is_missing $midx-$(midx_checksum $objdir).bitmap
-	)
-'
+		test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+		git clone --no-local . clone1 &&
 
-test_expect_success 'graceful fallback when missing reverse index' '
-	rm -fr repo &&
-	git init repo &&
-	test_when_finished "rm -fr repo" &&
-	(
-		cd repo &&
+		# Then generate a new pack which sorts ahead of any
+		# existing pack (by tweaking the pack prefix).
+		test_commit foo &&
+		git pack-objects --all --unpacked $objdir/pack/pack0 &&
 
-		test_commit base &&
+		# Generate a new MIDX which changes the preferred pack
+		# to a pack contained in the existing MIDX.
+		git multi-pack-index write --bitmap \
+			--preferred-pack="pack-$p2.pack" &&
+		test_path_is_file $midx &&
+		test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
 
-		# write a pack and MIDX bitmap containing base
-		git repack -adb &&
-		git multi-pack-index write --bitmap &&
-
-		GIT_TEST_MIDX_READ_RIDX=0 \
-			git rev-list --use-bitmap-index HEAD 2>err &&
-		! grep "ignoring extra bitmap file" err
+		# When the above circumstances are met, the preferred
+		# pack should change appropriately and clones should
+		# (still) succeed.
+		git clone --no-local . clone2
 	)
 '
 
diff --git a/t/t5327-multi-pack-bitmaps-rev.sh b/t/t5327-multi-pack-bitmaps-rev.sh
index d30ba63..e65e311 100755
--- a/t/t5327-multi-pack-bitmaps-rev.sh
+++ b/t/t5327-multi-pack-bitmaps-rev.sh
@@ -17,7 +17,27 @@
 export GIT_TEST_MIDX_WRITE_REV
 export GIT_TEST_MIDX_READ_RIDX
 
-midx_bitmap_core rev
-midx_bitmap_partial_tests rev
+test_midx_bitmap_rev () {
+	writeLookupTable=false
+
+	for i in "$@"
+	do
+		case $i in
+		"pack.writeBitmapLookupTable") writeLookupTable=true;;
+		esac
+	done
+
+	test_expect_success 'setup bitmap config' '
+		rm -rf * .git &&
+		git init &&
+		git config pack.writeBitmapLookupTable '"$writeLookupTable"'
+	'
+
+	midx_bitmap_core rev
+	midx_bitmap_partial_tests rev
+}
+
+test_midx_bitmap_rev
+test_midx_bitmap_rev "pack.writeBitmapLookupTable"
 
 test_done
diff --git a/t/t5329-pack-objects-cruft.sh b/t/t5329-pack-objects-cruft.sh
index 8968f7a..303f7a5 100755
--- a/t/t5329-pack-objects-cruft.sh
+++ b/t/t5329-pack-objects-cruft.sh
@@ -29,7 +29,8 @@
 				while read oid
 				do
 					path="$objdir/$(test_oid_to_path "$oid")" &&
-					printf "%s %d\n" "$oid" "$(test-tool chmtime --get "$path")"
+					printf "%s %d\n" "$oid" "$(test-tool chmtime --get "$path")" ||
+					echo "object list generation failed for $oid"
 				done |
 				sort -k1
 			) >expect &&
@@ -232,7 +233,7 @@
 		while read oid
 		do
 			test-tool chmtime -1000 \
-				"$objdir/$(test_oid_to_path $oid)"
+				"$objdir/$(test_oid_to_path $oid)" || exit 1
 		done <objects &&
 
 		test-tool chmtime -500 \
@@ -272,7 +273,7 @@
 		while read object
 		do
 			test-tool chmtime -1000 \
-				"$objdir/$(test_oid_to_path $object)"
+				"$objdir/$(test_oid_to_path $object)" || exit 1
 		done <objects &&
 		test-tool chmtime +500 "$objdir/$(test_oid_to_path \
 			$(git rev-parse HEAD))" &&
@@ -345,7 +346,7 @@
 		while read object
 		do
 			test-tool chmtime -1000 \
-				"$objdir/$(test_oid_to_path $object)"
+				"$objdir/$(test_oid_to_path $object)" || exit 1
 		done <objects &&
 
 		keep="$(basename "$(ls $packdir/pack-*.pack)")" &&
diff --git a/t/t5351-unpack-large-objects.sh b/t/t5351-unpack-large-objects.sh
new file mode 100755
index 0000000..8c8af99
--- /dev/null
+++ b/t/t5351-unpack-large-objects.sh
@@ -0,0 +1,103 @@
+#!/bin/sh
+#
+# Copyright (c) 2022 Han Xin
+#
+
+test_description='git unpack-objects with large objects'
+
+TEST_PASSES_SANITIZE_LEAK=true
+. ./test-lib.sh
+
+prepare_dest () {
+	test_when_finished "rm -rf dest.git" &&
+	git init --bare dest.git &&
+	git -C dest.git config core.bigFileThreshold "$1"
+}
+
+test_expect_success "create large objects (1.5 MB) and PACK" '
+	test-tool genrandom foo 1500000 >big-blob &&
+	test_commit --append foo big-blob &&
+	test-tool genrandom bar 1500000 >big-blob &&
+	test_commit --append bar big-blob &&
+	PACK=$(echo HEAD | git pack-objects --revs pack) &&
+	git verify-pack -v pack-$PACK.pack >out &&
+	sed -n -e "s/^\([0-9a-f][0-9a-f]*\).*\(commit\|tree\|blob\).*/\1/p" \
+		<out >obj-list
+'
+
+test_expect_success 'set memory limitation to 1MB' '
+	GIT_ALLOC_LIMIT=1m &&
+	export GIT_ALLOC_LIMIT
+'
+
+test_expect_success 'unpack-objects failed under memory limitation' '
+	prepare_dest 2m &&
+	test_must_fail git -C dest.git unpack-objects <pack-$PACK.pack 2>err &&
+	grep "fatal: attempting to allocate" err
+'
+
+test_expect_success 'unpack-objects works with memory limitation in dry-run mode' '
+	prepare_dest 2m &&
+	git -C dest.git unpack-objects -n <pack-$PACK.pack &&
+	test_stdout_line_count = 0 find dest.git/objects -type f &&
+	test_dir_is_empty dest.git/objects/pack
+'
+
+test_expect_success 'unpack big object in stream' '
+	prepare_dest 1m &&
+	git -C dest.git unpack-objects <pack-$PACK.pack &&
+	test_dir_is_empty dest.git/objects/pack
+'
+
+check_fsync_events () {
+	local trace="$1" &&
+	shift &&
+
+	cat >expect &&
+	sed -n \
+		-e '/^{"event":"data",.*"category":"fsync",/ {
+			s/.*"category":"fsync",//;
+			s/}$//;
+			p;
+		}' \
+		<"$trace" >actual &&
+	test_cmp expect actual
+}
+
+BATCH_CONFIGURATION='-c core.fsync=loose-object -c core.fsyncmethod=batch'
+
+test_expect_success 'unpack big object in stream (core.fsyncmethod=batch)' '
+	prepare_dest 1m &&
+	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" \
+	GIT_TEST_FSYNC=true \
+		git -C dest.git $BATCH_CONFIGURATION unpack-objects <pack-$PACK.pack &&
+	if grep "core.fsyncMethod = batch is unsupported" trace2.txt
+	then
+		flush_count=7
+	else
+		flush_count=1
+	fi &&
+	check_fsync_events trace2.txt <<-EOF &&
+	"key":"fsync/writeout-only","value":"6"
+	"key":"fsync/hardware-flush","value":"$flush_count"
+	EOF
+
+	test_dir_is_empty dest.git/objects/pack &&
+	git -C dest.git cat-file --batch-check="%(objectname)" <obj-list >current &&
+	cmp obj-list current
+'
+
+test_expect_success 'do not unpack existing large objects' '
+	prepare_dest 1m &&
+	git -C dest.git index-pack --stdin <pack-$PACK.pack &&
+	git -C dest.git unpack-objects <pack-$PACK.pack &&
+
+	# The destination came up with the exact same pack...
+	DEST_PACK=$(echo dest.git/objects/pack/pack-*.pack) &&
+	cmp pack-$PACK.pack $DEST_PACK &&
+
+	# ...and wrote no loose objects
+	test_stdout_line_count = 0 find dest.git/objects -type f ! -name "pack-*"
+'
+
+test_done
diff --git a/t/t5402-post-merge-hook.sh b/t/t5402-post-merge-hook.sh
index 915af2d..46ebdfb 100755
--- a/t/t5402-post-merge-hook.sh
+++ b/t/t5402-post-merge-hook.sh
@@ -7,6 +7,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t5500-fetch-pack.sh b/t/t5500-fetch-pack.sh
index ee6d2dd..d18f282 100755
--- a/t/t5500-fetch-pack.sh
+++ b/t/t5500-fetch-pack.sh
@@ -407,6 +407,7 @@
 '
 
 test_expect_success 'in_vain resetted upon ACK' '
+	test_when_finished rm -f log trace2 &&
 	rm -rf myserver myclient &&
 	git init myserver &&
 
@@ -432,7 +433,8 @@
 	# first. The 256th commit is common between the client and the server,
 	# and should reset in_vain. This allows negotiation to continue until
 	# the client reports that first_anotherbranch_commit is common.
-	git -C myclient fetch --progress origin main 2>log &&
+	GIT_TRACE2_EVENT="$(pwd)/trace2" git -C myclient fetch --progress origin main 2>log &&
+	grep \"key\":\"total_rounds\",\"value\":\"6\" trace2 &&
 	test_i18ngrep "Total 3 " log
 '
 
diff --git a/t/t5503-tagfollow.sh b/t/t5503-tagfollow.sh
index 195fc64..5ebbaa4 100755
--- a/t/t5503-tagfollow.sh
+++ b/t/t5503-tagfollow.sh
@@ -5,6 +5,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # End state of the repository:
diff --git a/t/t5505-remote.sh b/t/t5505-remote.sh
index fff14e1..9006196 100755
--- a/t/t5505-remote.sh
+++ b/t/t5505-remote.sh
@@ -241,6 +241,26 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'without subcommand' '
+	echo origin >expect &&
+	git -C test remote >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'without subcommand accepts -v' '
+	cat >expect <<-EOF &&
+	origin	$(pwd)/one (fetch)
+	origin	$(pwd)/one (push)
+	EOF
+	git -C test remote -v >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'without subcommand does not take arguments' '
+	test_expect_code 129 git -C test remote origin 2>err &&
+	grep "^error: unknown subcommand:" err
+'
+
 cat >test/expect <<EOF
 * remote origin
   Fetch URL: $(pwd)/one
@@ -302,6 +322,52 @@
 	)
 '
 
+cat >expect <<EOF
+* remote origin
+  Fetch URL: $(pwd)/one
+  Push  URL: $(pwd)/one
+  HEAD branch: main
+  Remote branches:
+    main skipped
+    side tracked
+  Local branches configured for 'git pull':
+    ahead merges with remote main
+    main  merges with remote main
+  Local refs configured for 'git push':
+    main pushes to main     (local out of date)
+    main pushes to upstream (create)
+EOF
+
+test_expect_success 'show with negative refspecs' '
+	test_when_finished "git -C test config --unset-all --fixed-value remote.origin.fetch ^refs/heads/main" &&
+	git -C test config --add remote.origin.fetch ^refs/heads/main &&
+	git -C test remote show origin >output &&
+	test_cmp expect output
+'
+
+cat >expect <<EOF
+* remote origin
+  Fetch URL: $(pwd)/one
+  Push  URL: $(pwd)/one
+  HEAD branch: main
+  Remote branches:
+    main new (next fetch will store in remotes/origin)
+    side stale (use 'git remote prune' to remove)
+  Local branches configured for 'git pull':
+    ahead merges with remote main
+    main  merges with remote main
+  Local refs configured for 'git push':
+    main pushes to main     (local out of date)
+    main pushes to upstream (create)
+EOF
+
+test_expect_failure 'show stale with negative refspecs' '
+	test_when_finished "git -C test config --unset-all --fixed-value remote.origin.fetch ^refs/heads/side" &&
+	git -C test config --add remote.origin.fetch ^refs/heads/side &&
+	git -C test remote show origin >output &&
+	test_cmp expect output
+'
+
 cat >test/expect <<EOF
 * remote origin
   Fetch URL: $(pwd)/one
@@ -957,11 +1023,12 @@
 '
 
 test_expect_success 'migrate a remote from named file in $GIT_DIR/branches' '
-	git clone one six &&
+	git clone --template= one six &&
 	origin_url=$(pwd)/one &&
 	(
 		cd six &&
 		git remote rm origin &&
+		mkdir .git/branches &&
 		echo "$origin_url#main" >.git/branches/origin &&
 		git remote rename origin origin &&
 		test_path_is_missing .git/branches/origin &&
@@ -972,10 +1039,11 @@
 '
 
 test_expect_success 'migrate a remote from named file in $GIT_DIR/branches (2)' '
-	git clone one seven &&
+	git clone --template= one seven &&
 	(
 		cd seven &&
 		git remote rm origin &&
+		mkdir .git/branches &&
 		echo "quux#foom" > .git/branches/origin &&
 		git remote rename origin origin &&
 		test_path_is_missing .git/branches/origin &&
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 541adbb..3211002 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -18,6 +18,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 D=$(pwd)
@@ -26,7 +27,8 @@
 	repo_name="$1"
 	test_when_finished "rm -rf \"$repo_name\"" &&
 	test_path_is_missing "$repo_name" &&
-	git init "$repo_name" &&
+	git init --template= "$repo_name" &&
+	mkdir "$repo_name"/.git/hooks &&
 	git -C "$repo_name" config receive.denyCurrentBranch warn
 }
 
@@ -78,7 +80,7 @@
 
 mk_child() {
 	test_when_finished "rm -rf \"$2\"" &&
-	git clone "$1" "$2"
+	git clone --template= "$1" "$2"
 }
 
 check_push_result () {
@@ -198,7 +200,10 @@
 	test_commit -C testrepo unrelated_commit &&
 	git -C testrepo config receive.hideRefs refs/remotes/origin/first_commit &&
 	test_when_finished "rm event" &&
-	GIT_TRACE2_EVENT="$(pwd)/event" git -c protocol.version=2 -c push.negotiate=1 push testrepo refs/heads/main:refs/remotes/origin/main &&
+	GIT_TRACE2_EVENT="$(pwd)/event" \
+		git -c protocol.version=2 -c push.negotiate=1 \
+		push testrepo refs/heads/main:refs/remotes/origin/main &&
+	grep \"key\":\"total_rounds\",\"value\":\"1\" event &&
 	grep_wrote 2 event # 1 commit, 1 tree
 '
 
@@ -222,7 +227,10 @@
 	git push testrepo $the_first_commit:refs/remotes/origin/first_commit &&
 	test_commit -C testrepo unrelated_commit &&
 	git -C testrepo config receive.hideRefs refs/remotes/origin/first_commit &&
-	git -c submodule.recurse=true -c protocol.version=2 -c push.negotiate=1 push testrepo refs/heads/main:refs/remotes/origin/main 2>err &&
+	GIT_TRACE2_EVENT="$(pwd)/event"  git -c submodule.recurse=true \
+		-c protocol.version=2 -c push.negotiate=1 \
+		push testrepo refs/heads/main:refs/remotes/origin/main 2>err &&
+	grep \"key\":\"total_rounds\",\"value\":\"1\" event &&
 	! grep "Fetching submodule" err
 '
 
@@ -937,6 +945,7 @@
 	mk_empty testrepo &&
 	git branch second $the_first_commit &&
 	git checkout second &&
+	mkdir testrepo/.git/branches &&
 	echo ".." > testrepo/.git/branches/branch1 &&
 	(
 		cd testrepo &&
@@ -950,6 +959,7 @@
 
 test_expect_success 'fetch with branches containing #' '
 	mk_empty testrepo &&
+	mkdir testrepo/.git/branches &&
 	echo "..#second" > testrepo/.git/branches/branch2 &&
 	(
 		cd testrepo &&
@@ -964,7 +974,11 @@
 test_expect_success 'push with branches' '
 	mk_empty testrepo &&
 	git checkout second &&
+
+	test_when_finished "rm -rf .git/branches" &&
+	mkdir .git/branches &&
 	echo "testrepo" > .git/branches/branch1 &&
+
 	git push branch1 &&
 	(
 		cd testrepo &&
@@ -976,7 +990,11 @@
 
 test_expect_success 'push with branches containing #' '
 	mk_empty testrepo &&
+
+	test_when_finished "rm -rf .git/branches" &&
+	mkdir .git/branches &&
 	echo "testrepo#branch3" > .git/branches/branch2 &&
+
 	git push branch2 &&
 	(
 		cd testrepo &&
@@ -1865,4 +1883,26 @@
 	test_line_count = 1 warnings
 '
 
+test_expect_success 'push with config push.useBitmaps' '
+	mk_test testrepo heads/main &&
+	git checkout main &&
+	test_unconfig push.useBitmaps &&
+	GIT_TRACE2_EVENT="$PWD/default" \
+	git push testrepo main:test &&
+	test_subcommand git pack-objects --all-progress-implied --revs --stdout \
+		--thin --delta-base-offset -q <default &&
+
+	test_config push.useBitmaps true &&
+	GIT_TRACE2_EVENT="$PWD/true" \
+	git push testrepo main:test2 &&
+	test_subcommand git pack-objects --all-progress-implied --revs --stdout \
+		--thin --delta-base-offset -q <true &&
+
+	test_config push.useBitmaps false &&
+	GIT_TRACE2_EVENT="$PWD/false" \
+	git push testrepo main:test3 &&
+	test_subcommand git pack-objects --all-progress-implied --revs --stdout \
+		--thin --delta-base-offset -q --no-use-bitmap-index <false
+'
+
 test_done
diff --git a/t/t5524-pull-msg.sh b/t/t5524-pull-msg.sh
index b2be360..56716e2 100755
--- a/t/t5524-pull-msg.sh
+++ b/t/t5524-pull-msg.sh
@@ -2,6 +2,7 @@
 
 test_description='git pull message generation'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 dollar='$Dollar'
diff --git a/t/t5541-http-push-smart.sh b/t/t5541-http-push-smart.sh
index 2f09ff4..fbad2d5 100755
--- a/t/t5541-http-push-smart.sh
+++ b/t/t5541-http-push-smart.sh
@@ -80,6 +80,25 @@
 	 test $HEAD = $(git rev-parse --verify HEAD))
 '
 
+test_expect_success 'push to remote repository (standard) with sending Accept-Language' '
+	cat >exp <<-\EOF &&
+	=> Send header: Accept-Language: ko-KR, *;q=0.9
+	=> Send header: Accept-Language: ko-KR, *;q=0.9
+	EOF
+
+	cd "$ROOT_PATH"/test_repo_clone &&
+	: >path_lang &&
+	git add path_lang &&
+	test_tick &&
+	git commit -m path_lang &&
+	HEAD=$(git rev-parse --verify HEAD) &&
+	GIT_TRACE_CURL=true LANGUAGE="ko_KR.UTF-8" git push -v -v 2>err &&
+	! grep "Expect: 100-continue" err &&
+
+	grep "=> Send header: Accept-Language:" err >err.language &&
+	test_cmp exp err.language
+'
+
 test_expect_success 'push already up-to-date' '
 	git push
 '
diff --git a/t/t5544-pack-objects-hook.sh b/t/t5544-pack-objects-hook.sh
index dd5f44d..54f54f8 100755
--- a/t/t5544-pack-objects-hook.sh
+++ b/t/t5544-pack-objects-hook.sh
@@ -56,7 +56,12 @@
 	! grep "hook running" stderr &&
 	test_path_is_missing .git/hook.args &&
 	test_path_is_missing .git/hook.stdin &&
-	test_path_is_missing .git/hook.stdout
+	test_path_is_missing .git/hook.stdout &&
+
+	# check that global config is used instead
+	test_config_global uploadpack.packObjectsHook ./hook &&
+	git clone --no-local . dst2.git 2>stderr &&
+	grep "hook running" stderr
 '
 
 test_expect_success 'hook works with partial clone' '
diff --git a/t/t5550-http-fetch-dumb.sh b/t/t5550-http-fetch-dumb.sh
index f0d9cd5..d7cf85f 100755
--- a/t/t5550-http-fetch-dumb.sh
+++ b/t/t5550-http-fetch-dumb.sh
@@ -369,7 +369,7 @@
 		ko_KR.EUC-KR:en_US.UTF-8:fr_CA:de.UTF-8@euro:sr@latin:ja:zh:sv:pt:nb
 '
 
-test_expect_success 'git client does not send an empty Accept-Language' '
+test_expect_success 'git client send an empty Accept-Language' '
 	GIT_TRACE_CURL=true LANGUAGE= git ls-remote "$HTTPD_URL/dumb/repo.git" 2>stderr &&
 	! grep "^=> Send header: Accept-Language:" stderr
 '
@@ -422,7 +422,8 @@
 	sha1=$(git -C "$victim" rev-parse HEAD) &&
 
 	evil=$HTTPD_DOCUMENT_ROOT_PATH/evil.git &&
-	git init --bare "$evil" &&
+	git init --template= --bare "$evil" &&
+	mkdir "$evil/info" &&
 	# do this by hand to avoid object existence check
 	printf "%s\\t%s\\n" $sha1 refs/heads/main >"$evil/info/refs"
 '
diff --git a/t/t5551-http-fetch-smart.sh b/t/t5551-http-fetch-smart.sh
index b9351a7..6a38294 100755
--- a/t/t5551-http-fetch-smart.sh
+++ b/t/t5551-http-fetch-smart.sh
@@ -31,6 +31,7 @@
 	> GET /smart/repo.git/info/refs?service=git-upload-pack HTTP/1.1
 	> Accept: */*
 	> Accept-Encoding: ENCODINGS
+	> Accept-Language: ko-KR, *;q=0.9
 	> Pragma: no-cache
 	< HTTP/1.1 200 OK
 	< Pragma: no-cache
@@ -40,13 +41,15 @@
 	> Accept-Encoding: ENCODINGS
 	> Content-Type: application/x-git-upload-pack-request
 	> Accept: application/x-git-upload-pack-result
+	> Accept-Language: ko-KR, *;q=0.9
 	> Content-Length: xxx
 	< HTTP/1.1 200 OK
 	< Pragma: no-cache
 	< Cache-Control: no-cache, max-age=0, must-revalidate
 	< Content-Type: application/x-git-upload-pack-result
 	EOF
-	GIT_TRACE_CURL=true GIT_TEST_PROTOCOL_VERSION=0 \
+
+	GIT_TRACE_CURL=true GIT_TEST_PROTOCOL_VERSION=0 LANGUAGE="ko_KR.UTF-8" \
 		git clone --quiet $HTTPD_URL/smart/repo.git clone 2>err &&
 	test_cmp file clone/file &&
 	tr '\''\015'\'' Q <err |
@@ -94,7 +97,10 @@
 		test_cmp exp actual.smudged &&
 
 		grep "Accept-Encoding:.*gzip" actual >actual.gzip &&
-		test_line_count = 2 actual.gzip
+		test_line_count = 2 actual.gzip &&
+
+		grep "Accept-Language: ko-KR, *" actual >actual.language &&
+		test_line_count = 2 actual.language
 	fi
 '
 
@@ -175,8 +181,8 @@
 	# This is not possible with protocol v2, since both objects and refs
 	# are obtained from the "git-upload-pack" path. A solution to this is
 	# to teach the server and client to be able to inline ls-refs requests
-	# as an Extra Parameter (see pack-protocol.txt), so that "info/refs"
-	# can serve refs, just like it does in protocol v0.
+	# as an Extra Parameter (see "git help gitformat-pack-protocol"), so that
+	# "info/refs" can serve refs, just like it does in protocol v0.
 	GIT_TEST_PROTOCOL_VERSION=0 git --git-dir=half-auth fetch &&
 	expect_askpass none
 '
diff --git a/t/t5557-http-get.sh b/t/t5557-http-get.sh
new file mode 100755
index 0000000..76a4bbd
--- /dev/null
+++ b/t/t5557-http-get.sh
@@ -0,0 +1,39 @@
+#!/bin/sh
+
+test_description='test downloading a file by URL'
+
+TEST_PASSES_SANITIZE_LEAK=true
+
+. ./test-lib.sh
+
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+test_expect_success 'get by URL: 404' '
+	test_when_finished "rm -f file.temp" &&
+	url="$HTTPD_URL/none.txt" &&
+	cat >input <<-EOF &&
+	capabilities
+	get $url file1
+	EOF
+
+	test_must_fail git remote-http $url <input 2>err &&
+	test_path_is_missing file1 &&
+	grep "failed to download file at URL" err
+'
+
+test_expect_success 'get by URL: 200' '
+	echo data >"$HTTPD_DOCUMENT_ROOT_PATH/exists.txt" &&
+
+	url="$HTTPD_URL/exists.txt" &&
+	cat >input <<-EOF &&
+	capabilities
+	get $url file2
+
+	EOF
+
+	git remote-http $url <input &&
+	test_cmp "$HTTPD_DOCUMENT_ROOT_PATH/exists.txt" file2
+'
+
+test_done
diff --git a/t/t5558-clone-bundle-uri.sh b/t/t5558-clone-bundle-uri.sh
new file mode 100755
index 0000000..ad666a2
--- /dev/null
+++ b/t/t5558-clone-bundle-uri.sh
@@ -0,0 +1,81 @@
+#!/bin/sh
+
+test_description='test fetching bundles with --bundle-uri'
+
+. ./test-lib.sh
+
+test_expect_success 'fail to clone from non-existent file' '
+	test_when_finished rm -rf test &&
+	git clone --bundle-uri="$(pwd)/does-not-exist" . test 2>err &&
+	grep "failed to download bundle from URI" err
+'
+
+test_expect_success 'fail to clone from non-bundle file' '
+	test_when_finished rm -rf test &&
+	echo bogus >bogus &&
+	git clone --bundle-uri="$(pwd)/bogus" . test 2>err &&
+	grep "is not a bundle" err
+'
+
+test_expect_success 'create bundle' '
+	git init clone-from &&
+	git -C clone-from checkout -b topic &&
+	test_commit -C clone-from A &&
+	test_commit -C clone-from B &&
+	git -C clone-from bundle create B.bundle topic
+'
+
+test_expect_success 'clone with path bundle' '
+	git clone --bundle-uri="clone-from/B.bundle" \
+		clone-from clone-path &&
+	git -C clone-path rev-parse refs/bundles/topic >actual &&
+	git -C clone-from rev-parse topic >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'clone with file:// bundle' '
+	git clone --bundle-uri="file://$(pwd)/clone-from/B.bundle" \
+		clone-from clone-file &&
+	git -C clone-file rev-parse refs/bundles/topic >actual &&
+	git -C clone-from rev-parse topic >expect &&
+	test_cmp expect actual
+'
+
+#########################################################################
+# HTTP tests begin here
+
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+test_expect_success 'fail to fetch from non-existent HTTP URL' '
+	test_when_finished rm -rf test &&
+	git clone --bundle-uri="$HTTPD_URL/does-not-exist" . test 2>err &&
+	grep "failed to download bundle from URI" err
+'
+
+test_expect_success 'fail to fetch from non-bundle HTTP URL' '
+	test_when_finished rm -rf test &&
+	echo bogus >"$HTTPD_DOCUMENT_ROOT_PATH/bogus" &&
+	git clone --bundle-uri="$HTTPD_URL/bogus" . test 2>err &&
+	grep "is not a bundle" err
+'
+
+test_expect_success 'clone HTTP bundle' '
+	cp clone-from/B.bundle "$HTTPD_DOCUMENT_ROOT_PATH/B.bundle" &&
+
+	git clone --no-local --mirror clone-from \
+		"$HTTPD_DOCUMENT_ROOT_PATH/fetch.git" &&
+
+	git clone --bundle-uri="$HTTPD_URL/B.bundle" \
+		"$HTTPD_URL/smart/fetch.git" clone-http &&
+	git -C clone-http rev-parse refs/bundles/topic >actual &&
+	git -C clone-from rev-parse topic >expect &&
+	test_cmp expect actual &&
+
+	test_config -C clone-http log.excludedecoration refs/bundle/
+'
+
+# Do not add tests here unless they use the HTTP server, as they will
+# not run unless the HTTP dependencies exist.
+
+test_done
diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index cf3be05..2e57de9 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -743,7 +743,11 @@
 
 	# Ensure that there is only one negotiation by checking that there is
 	# only "done" line sent. ("done" marks the end of negotiation.)
-	GIT_TRACE_PACKET="$(pwd)/trace" git -C client checkout HEAD^ &&
+	GIT_TRACE_PACKET="$(pwd)/trace" \
+		GIT_TRACE2_EVENT="$(pwd)/trace2_event" \
+		git -C client -c trace2.eventNesting=5 checkout HEAD^ &&
+	grep \"key\":\"total_rounds\",\"value\":\"1\" trace2_event >trace_lines &&
+	test_line_count = 1 trace_lines &&
 	grep "fetch> done" trace >done_lines &&
 	test_line_count = 1 done_lines
 '
diff --git a/t/t5606-clone-options.sh b/t/t5606-clone-options.sh
index 8f676d6..f6bb02a 100755
--- a/t/t5606-clone-options.sh
+++ b/t/t5606-clone-options.sh
@@ -58,6 +58,14 @@
 
 '
 
+test_expect_success 'disallows --bundle-uri with shallow options' '
+	for option in --depth=1 --shallow-since=01-01-2000 --shallow-exclude=HEAD
+	do
+		test_must_fail git clone --bundle-uri=bundle $option from to 2>err &&
+		grep "bundle-uri is incompatible" err || return 1
+	done
+'
+
 test_expect_success 'reject cloning shallow repository' '
 	test_when_finished "rm -rf repo" &&
 	test_must_fail git clone --reject-shallow shallow-repo out 2>err &&
diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
index 4a3778d..9aeacc2 100755
--- a/t/t5616-partial-clone.sh
+++ b/t/t5616-partial-clone.sh
@@ -49,6 +49,13 @@
 	test "$(git -C pc1 config --local remote.origin.partialclonefilter)" = "blob:none"
 '
 
+test_expect_success 'rev-list --missing=allow-promisor on partial clone' '
+	git -C pc1 rev-list --objects --missing=allow-promisor HEAD >actual &&
+	git -C pc1 rev-list --objects --missing=print HEAD >expect.raw &&
+	grep -v "^?" expect.raw >expect &&
+	test_cmp expect actual
+'
+
 test_expect_success 'verify that .promisor file contains refs fetched' '
 	ls pc1/.git/objects/pack/pack-*.promisor >promisorlist &&
 	test_line_count = 1 promisorlist &&
diff --git a/t/t5703-upload-pack-ref-in-want.sh b/t/t5703-upload-pack-ref-in-want.sh
index 9d6cd7d..df74f80 100755
--- a/t/t5703-upload-pack-ref-in-want.sh
+++ b/t/t5703-upload-pack-ref-in-want.sh
@@ -229,14 +229,16 @@
 '
 
 test_expect_success 'fetching with exact OID' '
-	test_when_finished "rm -f log" &&
+	test_when_finished "rm -f log trace2" &&
 
 	rm -rf local &&
 	cp -r "$LOCAL_PRISTINE" local &&
 	oid=$(git -C "$REPO" rev-parse d) &&
-	GIT_TRACE_PACKET="$(pwd)/log" git -C local fetch origin \
+	GIT_TRACE_PACKET="$(pwd)/log" GIT_TRACE2_EVENT="$(pwd)/trace2" \
+		git -C local fetch origin \
 		"$oid":refs/heads/actual &&
 
+	grep \"key\":\"total_rounds\",\"value\":\"2\" trace2 &&
 	git -C "$REPO" rev-parse "d" >expected &&
 	git -C local rev-parse refs/heads/actual >actual &&
 	test_cmp expected actual &&
diff --git a/t/t6001-rev-list-graft.sh b/t/t6001-rev-list-graft.sh
index 7294147..16635ec 100755
--- a/t/t6001-rev-list-graft.sh
+++ b/t/t6001-rev-list-graft.sh
@@ -99,6 +99,7 @@
 	"
 
 	test_expect_success 'with grafts' "
+		mkdir -p .git/info &&
 		echo '$B0 $A2' >.git/info/grafts &&
 		check $type $B2 -- $B2 $B1 $B0 $A2 $A1 $A0
 	"
diff --git a/t/t6008-rev-list-submodule.sh b/t/t6008-rev-list-submodule.sh
index 3153a0d..12e67e1 100755
--- a/t/t6008-rev-list-submodule.sh
+++ b/t/t6008-rev-list-submodule.sh
@@ -8,6 +8,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t6019-rev-list-ancestry-path.sh b/t/t6019-rev-list-ancestry-path.sh
index af57a04..738da23 100755
--- a/t/t6019-rev-list-ancestry-path.sh
+++ b/t/t6019-rev-list-ancestry-path.sh
@@ -8,8 +8,13 @@
 #   /                     \
 #  A-------K---------------L--M
 #
-#  D..M                 == E F G H I J K L M
-#  --ancestry-path D..M == E F H I J L M
+#  D..M                                     == E F G H I J K L M
+#  --ancestry-path                     D..M == E F   H I J   L M
+#  --ancestry-path=F                   D..M == E F       J   L M
+#  --ancestry-path=G                   D..M ==     G H I J   L M
+#  --ancestry-path=H                   D..M == E   G H I J   L M
+#  --ancestry-path=K                   D..M ==             K L M
+#  --ancestry-path=K --ancestry-path=F D..M == E F       J K L M
 #
 #  D..M -- M.t                 == M
 #  --ancestry-path D..M -- M.t == M
@@ -50,73 +55,41 @@
 	test_commit M
 '
 
-test_expect_success 'rev-list D..M' '
-	test_write_lines E F G H I J K L M >expect &&
-	git rev-list --format=%s D..M |
-	sed -e "/^commit /d" |
-	sort >actual &&
-	test_cmp expect actual
-'
+test_ancestry () {
+	args=$1
+	expected=$2
+	test_expect_success "log $args" "
+		test_write_lines $expected >expect &&
+		git log --format=%s $args >raw &&
 
-test_expect_success 'rev-list --ancestry-path D..M' '
-	test_write_lines E F H I J L M >expect &&
-	git rev-list --ancestry-path --format=%s D..M |
-	sed -e "/^commit /d" |
-	sort >actual &&
-	test_cmp expect actual
-'
+		if test -n \"$expected\"
+		then
+			sort raw >actual &&
+			test_cmp expect actual
+		else
+			test_must_be_empty raw
+		fi
+	"
+}
 
-test_expect_success 'rev-list D..M -- M.t' '
-	echo M >expect &&
-	git rev-list --format=%s D..M -- M.t |
-	sed -e "/^commit /d" >actual &&
-	test_cmp expect actual
-'
+test_ancestry "D..M" "E F G H I J K L M"
 
-test_expect_success 'rev-list --ancestry-path D..M -- M.t' '
-	echo M >expect &&
-	git rev-list --ancestry-path --format=%s D..M -- M.t |
-	sed -e "/^commit /d" >actual &&
-	test_cmp expect actual
-'
+test_ancestry "--ancestry-path D..M" "E F H I J L M"
+test_ancestry "--ancestry-path=F D..M" "E F J L M"
+test_ancestry "--ancestry-path=G D..M" "G H I J L M"
+test_ancestry "--ancestry-path=H D..M" "E G H I J L M"
+test_ancestry "--ancestry-path=K D..M" "K L M"
+test_ancestry "--ancestry-path=F --ancestry-path=K D..M" "E F J K L M"
 
-test_expect_success 'rev-list F...I' '
-	test_write_lines F G H I >expect &&
-	git rev-list --format=%s F...I |
-	sed -e "/^commit /d" |
-	sort >actual &&
-	test_cmp expect actual
-'
+test_ancestry "D..M -- M.t" "M"
+test_ancestry "--ancestry-path D..M -- M.t" "M"
 
-test_expect_success 'rev-list --ancestry-path F...I' '
-	test_write_lines F H I >expect &&
-	git rev-list --ancestry-path --format=%s F...I |
-	sed -e "/^commit /d" |
-	sort >actual &&
-	test_cmp expect actual
-'
+test_ancestry "F...I" "F G H I"
+test_ancestry "--ancestry-path F...I" "F H I"
 
-# G.t is dropped in an "-s ours" merge
-test_expect_success 'rev-list G..M -- G.t' '
-	git rev-list --format=%s G..M -- G.t |
-	sed -e "/^commit /d" >actual &&
-	test_must_be_empty actual
-'
-
-test_expect_success 'rev-list --ancestry-path G..M -- G.t' '
-	echo L >expect &&
-	git rev-list --ancestry-path --format=%s G..M -- G.t |
-	sed -e "/^commit /d" >actual &&
-	test_cmp expect actual
-'
-
-test_expect_success 'rev-list --ancestry-path --simplify-merges G^..M -- G.t' '
-	test_write_lines G L >expect &&
-	git rev-list --ancestry-path --simplify-merges --format=%s G^..M -- G.t |
-	sed -e "/^commit /d" |
-	sort >actual &&
-	test_cmp expect actual
-'
+test_ancestry "G..M -- G.t" ""
+test_ancestry "--ancestry-path G..M -- G.t" "L"
+test_ancestry "--ancestry-path --simplify-merges G^..M -- G.t" "G L"
 
 #   b---bc
 #  / \ /
diff --git a/t/t6101-rev-parse-parents.sh b/t/t6101-rev-parse-parents.sh
index a3a41c7..d20723d 100755
--- a/t/t6101-rev-parse-parents.sh
+++ b/t/t6101-rev-parse-parents.sh
@@ -9,6 +9,7 @@
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 TEST_PASSES_SANITIZE_LEAK=true
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 test_cmp_rev_output () {
@@ -26,6 +27,7 @@
 	git merge -m next --allow-unrelated-histories start2 &&
 	test_commit final &&
 
+	mkdir .git/info &&
 	test_seq 40 |
 	while read i
 	do
diff --git a/t/t6102-rev-list-unexpected-objects.sh b/t/t6102-rev-list-unexpected-objects.sh
index cf0195e..4a9a443 100755
--- a/t/t6102-rev-list-unexpected-objects.sh
+++ b/t/t6102-rev-list-unexpected-objects.sh
@@ -17,7 +17,7 @@
 	broken_tree="$(git hash-object -w --literally -t tree broken-tree)"
 '
 
-test_expect_success !SANITIZE_LEAK 'TODO (should fail!): traverse unexpected non-blob entry (lone)' '
+test_expect_success 'TODO (should fail!): traverse unexpected non-blob entry (lone)' '
 	sed "s/Z$//" >expect <<-EOF &&
 	$broken_tree Z
 	$tree foo
@@ -121,7 +121,7 @@
 	tag=$(git hash-object -w --literally -t tag broken-tag)
 '
 
-test_expect_success !SANITIZE_LEAK 'TODO (should fail!): traverse unexpected non-blob tag (lone)' '
+test_expect_success 'TODO (should fail!): traverse unexpected non-blob tag (lone)' '
 	git rev-list --objects $tag
 '
 
diff --git a/t/t6115-rev-list-du.sh b/t/t6115-rev-list-du.sh
index b4aef32..d59111d 100755
--- a/t/t6115-rev-list-du.sh
+++ b/t/t6115-rev-list-du.sh
@@ -48,4 +48,26 @@
 check_du --objects HEAD
 check_du --objects HEAD^..HEAD
 
+# As mentioned above, don't use hardcode sizes as actual size, but use the
+# output from git cat-file.
+test_expect_success 'rev-list --disk-usage=human' '
+	git rev-list --objects HEAD --disk-usage=human >actual &&
+	disk_usage_slow --objects HEAD >actual_size &&
+	grep "$(cat actual_size) bytes" actual
+'
+
+test_expect_success 'rev-list --disk-usage=human with bitmaps' '
+	git rev-list --objects HEAD --use-bitmap-index --disk-usage=human >actual &&
+	disk_usage_slow --objects HEAD >actual_size &&
+	grep "$(cat actual_size) bytes" actual
+'
+
+test_expect_success 'rev-list use --disk-usage unproperly' '
+	test_must_fail git rev-list --objects HEAD --disk-usage=typo 2>err &&
+	cat >expect <<-\EOF &&
+	fatal: invalid value for '\''--disk-usage=<format>'\'': '\''typo'\'', the only allowed format is '\''human'\''
+	EOF
+	test_cmp err expect
+'
+
 test_done
diff --git a/t/t6132-pathspec-exclude.sh b/t/t6132-pathspec-exclude.sh
index 9fdafeb..cada952 100755
--- a/t/t6132-pathspec-exclude.sh
+++ b/t/t6132-pathspec-exclude.sh
@@ -293,7 +293,11 @@
 	test_cmp expect actual
 '
 
-test_expect_success 'add -p with all negative' '
+test_lazy_prereq ADD_I_USE_BUILTIN_OR_PERL '
+	test_have_prereq ADD_I_USE_BUILTIN || test_have_prereq PERL
+'
+
+test_expect_success ADD_I_USE_BUILTIN_OR_PERL 'add -p with all negative' '
 	H=$(git rev-parse HEAD) &&
 	git reset --hard $H &&
 	git clean -f &&
diff --git a/t/t6134-pathspec-in-submodule.sh b/t/t6134-pathspec-in-submodule.sh
index 0f1cb49..3a241f2 100755
--- a/t/t6134-pathspec-in-submodule.sh
+++ b/t/t6134-pathspec-in-submodule.sh
@@ -2,6 +2,7 @@
 
 test_description='test case exclude pathspec'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup a submodule' '
diff --git a/t/t6400-merge-df.sh b/t/t6400-merge-df.sh
index 57a67cf..3de4ef6 100755
--- a/t/t6400-merge-df.sh
+++ b/t/t6400-merge-df.sh
@@ -126,7 +126,7 @@
 	#     foo/bar-2/baz
 	# The fact that foo/bar-2 appears between foo/bar and foo/bar/baz
 	# can trip up some codepaths, and is the point of this test.
-	test_create_repo name-ordering &&
+	git init name-ordering &&
 	(
 		cd name-ordering &&
 
diff --git a/t/t6402-merge-rename.sh b/t/t6402-merge-rename.sh
index 3a32b1a..772238e 100755
--- a/t/t6402-merge-rename.sh
+++ b/t/t6402-merge-rename.sh
@@ -210,7 +210,7 @@
 	echo >>M one line addition &&
 	cat M >M.saved &&
 	git update-index M &&
-	test_expect_code 128 git pull --no-rebase . yellow &&
+	test_expect_code 2 git pull --no-rebase . yellow &&
 	test_cmp M M.saved &&
 	rm -f M.saved
 '
diff --git a/t/t6403-merge-file.sh b/t/t6403-merge-file.sh
index 2f421d9..1a70823 100755
--- a/t/t6403-merge-file.sh
+++ b/t/t6403-merge-file.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='RCS merge replacement: merge-file'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t6404-recursive-merge.sh b/t/t6404-recursive-merge.sh
index b8735c6..3621551 100755
--- a/t/t6404-recursive-merge.sh
+++ b/t/t6404-recursive-merge.sh
@@ -4,6 +4,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # This scenario is based on a real-world repository of Shawn Pearce.
diff --git a/t/t6405-merge-symlinks.sh b/t/t6405-merge-symlinks.sh
index 7435fce..29e2b25 100755
--- a/t/t6405-merge-symlinks.sh
+++ b/t/t6405-merge-symlinks.sh
@@ -11,6 +11,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t6406-merge-attr.sh b/t/t6406-merge-attr.sh
index 99abefd..8650a88 100755
--- a/t/t6406-merge-attr.sh
+++ b/t/t6406-merge-attr.sh
@@ -162,8 +162,8 @@
 '
 
 test_expect_success 'up-to-date merge without common ancestor' '
-	test_create_repo repo1 &&
-	test_create_repo repo2 &&
+	git init repo1 &&
+	git init repo2 &&
 	test_tick &&
 	(
 		cd repo1 &&
diff --git a/t/t6407-merge-binary.sh b/t/t6407-merge-binary.sh
index 0753fc9..e8a2871 100755
--- a/t/t6407-merge-binary.sh
+++ b/t/t6407-merge-binary.sh
@@ -5,7 +5,6 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
-TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t6408-merge-up-to-date.sh b/t/t6408-merge-up-to-date.sh
index 7763c1b..8a1ba6d 100755
--- a/t/t6408-merge-up-to-date.sh
+++ b/t/t6408-merge-up-to-date.sh
@@ -2,6 +2,7 @@
 
 test_description='merge fast-forward and up to date'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t6411-merge-filemode.sh b/t/t6411-merge-filemode.sh
index 6ae2489..b618272 100755
--- a/t/t6411-merge-filemode.sh
+++ b/t/t6411-merge-filemode.sh
@@ -4,6 +4,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'set up mode change in one branch' '
diff --git a/t/t6413-merge-crlf.sh b/t/t6413-merge-crlf.sh
index affea25..b4f4a31 100755
--- a/t/t6413-merge-crlf.sh
+++ b/t/t6413-merge-crlf.sh
@@ -11,6 +11,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t6416-recursive-corner-cases.sh b/t/t6416-recursive-corner-cases.sh
index 690c848..17b54d6 100755
--- a/t/t6416-recursive-corner-cases.sh
+++ b/t/t6416-recursive-corner-cases.sh
@@ -19,7 +19,7 @@
 #
 
 test_expect_success 'setup basic criss-cross + rename with no modifications' '
-	test_create_repo basic-rename &&
+	git init basic-rename &&
 	(
 		cd basic-rename &&
 
@@ -85,7 +85,7 @@
 #
 
 test_expect_success 'setup criss-cross + rename merges with basic modification' '
-	test_create_repo rename-modify &&
+	git init rename-modify &&
 	(
 		cd rename-modify &&
 
@@ -160,7 +160,7 @@
 #
 
 test_expect_success 'setup differently handled merges of rename/add conflict' '
-	test_create_repo rename-add &&
+	git init rename-add &&
 	(
 		cd rename-add &&
 
@@ -324,7 +324,7 @@
 # Merging commits D & E should result in modify/delete conflict.
 
 test_expect_success 'setup criss-cross + modify/delete resolved differently' '
-	test_create_repo modify-delete &&
+	git init modify-delete &&
 	(
 		cd modify-delete &&
 
@@ -499,7 +499,7 @@
 #
 
 test_expect_success 'setup differently handled merges of directory/file conflict' '
-	test_create_repo directory-file &&
+	git init directory-file &&
 	(
 		cd directory-file &&
 
@@ -867,7 +867,7 @@
 # but that may cancel out at the final merge stage".
 
 test_expect_success 'setup rename/rename(1to2)/modify followed by what looks like rename/rename(2to1)/modify' '
-	test_create_repo rename-squared-squared &&
+	git init rename-squared-squared &&
 	(
 		cd rename-squared-squared &&
 
@@ -944,7 +944,7 @@
 # content merge handled.
 
 test_expect_success 'setup criss-cross + rename/rename/add-source + modify/modify' '
-	test_create_repo rename-rename-add-source &&
+	git init rename-rename-add-source &&
 	(
 		cd rename-rename-add-source &&
 
@@ -1032,7 +1032,7 @@
 # base of B & C needs to not delete B:c for that to work, though...
 
 test_expect_success 'setup criss-cross+rename/rename/add-dest + simple modify' '
-	test_create_repo rename-rename-add-dest &&
+	git init rename-rename-add-dest &&
 	(
 		cd rename-rename-add-dest &&
 
@@ -1111,7 +1111,7 @@
 # git detect it?
 
 test_expect_success 'setup symlink modify/modify' '
-	test_create_repo symlink-modify-modify &&
+	git init symlink-modify-modify &&
 	(
 		cd symlink-modify-modify &&
 
@@ -1178,7 +1178,7 @@
 # git detect it?
 
 test_expect_success 'setup symlink add/add' '
-	test_create_repo symlink-add-add &&
+	git init symlink-add-add &&
 	(
 		cd symlink-add-add &&
 
@@ -1244,11 +1244,11 @@
 # git detect it?
 
 test_expect_success 'setup submodule modify/modify' '
-	test_create_repo submodule-modify-modify &&
+	git init submodule-modify-modify &&
 	(
 		cd submodule-modify-modify &&
 
-		test_create_repo submod &&
+		git init submod &&
 		(
 			cd submod &&
 			touch file-A &&
@@ -1332,11 +1332,11 @@
 # git detect it?
 
 test_expect_success 'setup submodule add/add' '
-	test_create_repo submodule-add-add &&
+	git init submodule-add-add &&
 	(
 		cd submodule-add-add &&
 
-		test_create_repo submod &&
+		git init submod &&
 		(
 			cd submod &&
 			touch file-A &&
@@ -1419,11 +1419,11 @@
 # This is an obvious add/add conflict for 'path'.  Can git detect it?
 
 test_expect_success 'setup conflicting entry types (submodule vs symlink)' '
-	test_create_repo submodule-symlink-add-add &&
+	git init submodule-symlink-add-add &&
 	(
 		cd submodule-symlink-add-add &&
 
-		test_create_repo path &&
+		git init path &&
 		(
 			cd path &&
 			touch file-B &&
@@ -1494,7 +1494,7 @@
 # This is an obvious add/add mode conflict.  Can git detect it?
 
 test_expect_success 'setup conflicting modes for regular file' '
-	test_create_repo regular-file-mode-conflict &&
+	git init regular-file-mode-conflict &&
 	(
 		cd regular-file-mode-conflict &&
 
@@ -1571,7 +1571,7 @@
 #   to ensure that we handle it as well as practical.
 
 test_expect_success 'setup nested conflicts' '
-	test_create_repo nested_conflicts &&
+	git init nested_conflicts &&
 	(
 		cd nested_conflicts &&
 
@@ -1757,7 +1757,7 @@
 #   have three levels of conflict markers.  Can we distinguish all three?
 
 test_expect_success 'setup virtual merge base with nested conflicts' '
-	test_create_repo virtual_merge_base_has_nested_conflicts &&
+	git init virtual_merge_base_has_nested_conflicts &&
 	(
 		cd virtual_merge_base_has_nested_conflicts &&
 
diff --git a/t/t6417-merge-ours-theirs.sh b/t/t6417-merge-ours-theirs.sh
index 62d1406..482b73a 100755
--- a/t/t6417-merge-ours-theirs.sh
+++ b/t/t6417-merge-ours-theirs.sh
@@ -4,6 +4,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t6421-merge-partial-clone.sh b/t/t6421-merge-partial-clone.sh
index 36bcd7c3..5413e5d 100755
--- a/t/t6421-merge-partial-clone.sh
+++ b/t/t6421-merge-partial-clone.sh
@@ -31,7 +31,7 @@
 
 test_setup_repo () {
 	test -d server && return
-	test_create_repo server &&
+	git init server &&
 	(
 		cd server &&
 
diff --git a/t/t6422-merge-rename-corner-cases.sh b/t/t6422-merge-rename-corner-cases.sh
index bf4ce3c..346253c 100755
--- a/t/t6422-merge-rename-corner-cases.sh
+++ b/t/t6422-merge-rename-corner-cases.sh
@@ -6,11 +6,12 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-merge.sh
 
 test_setup_rename_delete_untracked () {
-	test_create_repo rename-delete-untracked &&
+	git init rename-delete-untracked &&
 	(
 		cd rename-delete-untracked &&
 
@@ -55,7 +56,7 @@
 # We should be able to merge B & C cleanly
 
 test_setup_rename_modify_add_source () {
-	test_create_repo rename-modify-add-source &&
+	git init rename-modify-add-source &&
 	(
 		cd rename-modify-add-source &&
 
@@ -95,7 +96,7 @@
 '
 
 test_setup_break_detection_1 () {
-	test_create_repo break-detection-1 &&
+	git init break-detection-1 &&
 	(
 		cd break-detection-1 &&
 
@@ -143,7 +144,7 @@
 '
 
 test_setup_break_detection_2 () {
-	test_create_repo break-detection-2 &&
+	git init break-detection-2 &&
 	(
 		cd break-detection-2 &&
 
@@ -191,7 +192,7 @@
 #   Commit C: rename a->b, add unrelated a
 
 test_setup_break_detection_3 () {
-	test_create_repo break-detection-3 &&
+	git init break-detection-3 &&
 	(
 		cd break-detection-3 &&
 
@@ -267,7 +268,7 @@
 '
 
 test_setup_rename_directory () {
-	test_create_repo rename-directory-$1 &&
+	git init rename-directory-$1 &&
 	(
 		cd rename-directory-$1 &&
 
@@ -385,7 +386,7 @@
 '
 
 test_setup_rename_directory_2 () {
-	test_create_repo rename-directory-2 &&
+	git init rename-directory-2 &&
 	(
 		cd rename-directory-2 &&
 
@@ -444,7 +445,7 @@
 #   Commit B: modify a, add different b
 
 test_setup_rename_with_content_merge_and_add () {
-	test_create_repo rename-with-content-merge-and-add-$1 &&
+	git init rename-with-content-merge-and-add-$1 &&
 	(
 		cd rename-with-content-merge-and-add-$1 &&
 
@@ -569,7 +570,7 @@
 #   * Nothing else should be present.  Is anything?
 
 test_setup_rename_rename_2to1 () {
-	test_create_repo rename-rename-2to1 &&
+	git init rename-rename-2to1 &&
 	(
 		cd rename-rename-2to1 &&
 
@@ -641,7 +642,7 @@
 #   Commit B: rename a->b
 #   Commit C: rename a->c
 test_setup_rename_rename_1to2 () {
-	test_create_repo rename-rename-1to2 &&
+	git init rename-rename-1to2 &&
 	(
 		cd rename-rename-1to2 &&
 
@@ -699,7 +700,7 @@
 # Merging of B & C should NOT be clean; there's a rename/rename conflict
 
 test_setup_rename_rename_1to2_add_source_1 () {
-	test_create_repo rename-rename-1to2-add-source-1 &&
+	git init rename-rename-1to2-add-source-1 &&
 	(
 		cd rename-rename-1to2-add-source-1 &&
 
@@ -747,7 +748,7 @@
 '
 
 test_setup_rename_rename_1to2_add_source_2 () {
-	test_create_repo rename-rename-1to2-add-source-2 &&
+	git init rename-rename-1to2-add-source-2 &&
 	(
 		cd rename-rename-1to2-add-source-2 &&
 
@@ -793,7 +794,7 @@
 '
 
 test_setup_rename_rename_1to2_add_dest () {
-	test_create_repo rename-rename-1to2-add-dest &&
+	git init rename-rename-1to2-add-dest &&
 	(
 		cd rename-rename-1to2-add-dest &&
 
@@ -873,7 +874,7 @@
 #   Expected: CONFLICT (rename/add/delete), two-way merged bar
 
 test_setup_rad () {
-	test_create_repo rad &&
+	git init rad &&
 	(
 		cd rad &&
 		echo "original file" >foo &&
@@ -945,7 +946,7 @@
 #   Expected: CONFLICT (rename/rename/delete/delete), two-way merged baz
 
 test_setup_rrdd () {
-	test_create_repo rrdd &&
+	git init rrdd &&
 	(
 		cd rrdd &&
 		echo foo >foo &&
@@ -1021,7 +1022,7 @@
 #             multi-way merged contents found in two, four, six
 
 test_setup_mod6 () {
-	test_create_repo mod6 &&
+	git init mod6 &&
 	(
 		cd mod6 &&
 		test_seq 11 19 >one &&
@@ -1159,7 +1160,7 @@
 	#      tree
 	test_setup_collision_conflict () {
 	#test_expect_success "setup simple $sideL/$sideR conflict" '
-		test_create_repo simple_${sideL}_${sideR} &&
+		git init simple_${sideL}_${sideR} &&
 		(
 			cd simple_${sideL}_${sideR} &&
 
@@ -1307,7 +1308,7 @@
 #   So, we have four different conflicting files that all end up at path
 #   'three'.
 test_setup_nested_conflicts_from_rename_rename () {
-	test_create_repo nested_conflicts_from_rename_rename &&
+	git init nested_conflicts_from_rename_rename &&
 	(
 		cd nested_conflicts_from_rename_rename &&
 
@@ -1416,7 +1417,7 @@
 #   Expected: CONFLICT(rename/rename) message, three unstaged entries in the
 #             index, and contents of orig-[AB] at path orig-[AB]
 test_setup_rename_rename_1_to_2_binary () {
-	test_create_repo rename_rename_1_to_2_binary &&
+	git init rename_rename_1_to_2_binary &&
 	(
 		cd rename_rename_1_to_2_binary &&
 
diff --git a/t/t6423-merge-rename-directories.sh b/t/t6423-merge-rename-directories.sh
index 99baf77..a494187 100755
--- a/t/t6423-merge-rename-directories.sh
+++ b/t/t6423-merge-rename-directories.sh
@@ -40,7 +40,7 @@
 #   Expected: y/{b,c,d,e/f}
 
 test_setup_1a () {
-	test_create_repo 1a &&
+	git init 1a &&
 	(
 		cd 1a &&
 
@@ -106,7 +106,7 @@
 #   Expected: y/{b,c,d,e}
 
 test_setup_1b () {
-	test_create_repo 1b &&
+	git init 1b &&
 	(
 		cd 1b &&
 
@@ -169,7 +169,7 @@
 #   Expected: y/{b,c,d}  (because x/d -> z/d -> y/d)
 
 test_setup_1c () {
-	test_create_repo 1c &&
+	git init 1c &&
 	(
 		cd 1c &&
 
@@ -232,7 +232,7 @@
 #         y/wham_1 & z/wham_2 should too...giving us a conflict.
 
 test_setup_1d () {
-	test_create_repo 1d &&
+	git init 1d &&
 	(
 		cd 1d &&
 
@@ -328,7 +328,7 @@
 #   Expected: y/{newb,newc,d}
 
 test_setup_1e () {
-	test_create_repo 1e &&
+	git init 1e &&
 	(
 		cd 1e &&
 
@@ -387,7 +387,7 @@
 #   Expected: y/{b,c}, x/{d,e,f,g}
 
 test_setup_1f () {
-	test_create_repo 1f &&
+	git init 1f &&
 	(
 		cd 1f &&
 
@@ -476,7 +476,7 @@
 #   Commit B: z/{b,c,d}
 #   Expected: y/b, w/c, z/d, with warning about z/ -> (y/ vs. w/) conflict
 test_setup_2a () {
-	test_create_repo 2a &&
+	git init 2a &&
 	(
 		cd 2a &&
 
@@ -538,7 +538,7 @@
 #   Commit B: z/{b,c}, x/d
 #   Expected: y/b, w/c, x/d; No warning about z/ -> (y/ vs. w/) conflict
 test_setup_2b () {
-	test_create_repo 2b &&
+	git init 2b &&
 	(
 		cd 2b &&
 
@@ -620,7 +620,7 @@
 #   Commit B: y/{b,c}, x/d
 #   Expected: y/{b,c}, x/d
 test_setup_3a () {
-	test_create_repo 3a &&
+	git init 3a &&
 	(
 		cd 3a &&
 
@@ -684,7 +684,7 @@
 #         end up with CONFLICT:(z/d -> y/d vs. x/d vs. w/d), i.e. a
 #         rename/rename/rename(1to3) conflict, which is just weird.
 test_setup_3b () {
-	test_create_repo 3b &&
+	git init 3b &&
 	(
 		cd 3b &&
 
@@ -807,7 +807,7 @@
 #   NOTE: Even though most files from z moved to y, we don't want f to follow.
 
 test_setup_4a () {
-	test_create_repo 4a &&
+	git init 4a &&
 	(
 		cd 4a &&
 
@@ -896,7 +896,7 @@
 #         index.
 
 test_setup_5a () {
-	test_create_repo 5a &&
+	git init 5a &&
 	(
 		cd 5a &&
 
@@ -971,7 +971,7 @@
 #         back to git behavior without the directory rename detection.
 
 test_setup_5b () {
-	test_create_repo 5b &&
+	git init 5b &&
 	(
 		cd 5b &&
 
@@ -1048,7 +1048,7 @@
 #             though, because it doesn't have anything in the way.
 
 test_setup_5c () {
-	test_create_repo 5c &&
+	git init 5c &&
 	(
 		cd 5c &&
 
@@ -1138,7 +1138,7 @@
 #         directory rename detection for z/f -> y/f.
 
 test_setup_5d () {
-	test_create_repo 5d &&
+	git init 5d &&
 	(
 		cd 5d &&
 
@@ -1239,7 +1239,7 @@
 #         it is also involved in a rename/delete conflict.
 
 test_setup_6a () {
-	test_create_repo 6a &&
+	git init 6a &&
 	(
 		cd 6a &&
 
@@ -1337,7 +1337,7 @@
 #         the behavior on testcases 6b2 and 8e, and introduced this 6b1 testcase.
 
 test_setup_6b1 () {
-	test_create_repo 6b1 &&
+	git init 6b1 &&
 	(
 		cd 6b1 &&
 
@@ -1415,7 +1415,7 @@
 #         the z/ -> y/ rename.
 
 test_setup_6b2 () {
-	test_create_repo 6b2 &&
+	git init 6b2 &&
 	(
 		cd 6b2 &&
 
@@ -1479,7 +1479,7 @@
 #         "accidentally detect a rename" and give us y/{b,c,d}.
 
 test_setup_6c () {
-	test_create_repo 6c &&
+	git init 6c &&
 	(
 		cd 6c &&
 
@@ -1542,7 +1542,7 @@
 #         doesn't "accidentally detect a rename" and give us y/{b,c,d}.
 
 test_setup_6d () {
-	test_create_repo 6d &&
+	git init 6d &&
 	(
 		cd 6d &&
 
@@ -1605,7 +1605,7 @@
 #         add/add conflict on y/d_1 vs y/d_2.
 
 test_setup_6e () {
-	test_create_repo 6e &&
+	git init 6e &&
 	(
 		cd 6e &&
 
@@ -1700,7 +1700,7 @@
 #   NOTE: There's a rename of z/ here, y/ has more renames, so z/d -> y/d.
 
 test_setup_7a () {
-	test_create_repo 7a &&
+	git init 7a &&
 	(
 		cd 7a &&
 
@@ -1772,7 +1772,7 @@
 #   Expected: y/{b,c}, CONFLICT(rename/rename(2to1): x/d_1, w/d_2 -> y_d)
 
 test_setup_7b () {
-	test_create_repo 7b &&
+	git init 7b &&
 	(
 		cd 7b &&
 
@@ -1861,7 +1861,7 @@
 #         nor CONFLiCT x/d -> w/d vs. y/d vs. z/d)
 
 test_setup_7c () {
-	test_create_repo 7c &&
+	git init 7c &&
 	(
 		cd 7c &&
 
@@ -1926,7 +1926,7 @@
 #   NOTE: z->y so NOT CONFLICT(delete x/d vs rename to z/d)
 
 test_setup_7d () {
-	test_create_repo 7d &&
+	git init 7d &&
 	(
 		cd 7d &&
 
@@ -2027,7 +2027,7 @@
 #         how it's resolved.
 
 test_setup_7e () {
-	test_create_repo 7e &&
+	git init 7e &&
 	(
 		cd 7e &&
 
@@ -2137,7 +2137,7 @@
 # we potentially could.
 
 test_setup_8a () {
-	test_create_repo 8a &&
+	git init 8a &&
 	(
 		cd 8a &&
 
@@ -2216,7 +2216,7 @@
 # e_1 and e_2.
 
 test_setup_8b () {
-	test_create_repo 8b &&
+	git init 8b &&
 	(
 		cd 8b &&
 
@@ -2290,7 +2290,7 @@
 #         notes in 8d.
 
 test_setup_8c () {
-	test_create_repo 8c &&
+	git init 8c &&
 	(
 		cd 8c &&
 
@@ -2370,7 +2370,7 @@
 #   differently.
 
 test_setup_8d () {
-	test_create_repo 8d &&
+	git init 8d &&
 	(
 		cd 8d &&
 
@@ -2453,7 +2453,7 @@
 #        the behavior, and predict it without computing as many details.
 
 test_setup_8e () {
-	test_create_repo 8e &&
+	git init 8e &&
 	(
 		cd 8e &&
 
@@ -2537,7 +2537,7 @@
 #         of that could take the new file in commit B at z/i to x/w/i or x/i.
 
 test_setup_9a () {
-	test_create_repo 9a &&
+	git init 9a &&
 	(
 		cd 9a &&
 
@@ -2609,7 +2609,7 @@
 #   Expected: y/{b,c,d_merged}
 
 test_setup_9b () {
-	test_create_repo 9b &&
+	git init 9b &&
 	(
 		cd 9b &&
 
@@ -2697,7 +2697,7 @@
 #         history for any implicit directory renames.
 
 test_setup_9c () {
-	test_create_repo 9c &&
+	git init 9c &&
 	(
 		cd 9c &&
 
@@ -2786,7 +2786,7 @@
 #   testcases and simplifies things for the user.
 
 test_setup_9d () {
-	test_create_repo 9d &&
+	git init 9d &&
 	(
 		cd 9d &&
 
@@ -2861,7 +2861,7 @@
 #             dir1/yo, dir2/yo, dir3/yo, dirN/yo
 
 test_setup_9e () {
-	test_create_repo 9e &&
+	git init 9e &&
 	(
 		cd 9e &&
 
@@ -2954,7 +2954,7 @@
 #   Expected: priority/{a,b}/$more_files, priority/c
 
 test_setup_9f () {
-	test_create_repo 9f &&
+	git init 9f &&
 	(
 		cd 9f &&
 
@@ -3027,7 +3027,7 @@
 # viewpoint...
 
 test_setup_9g () {
-	test_create_repo 9g &&
+	git init 9g &&
 	(
 		cd 9g &&
 
@@ -3096,7 +3096,7 @@
 #   NOTE: If we applied the z/ -> y/ rename to z/d, then we'd end up with
 #         a rename/rename(1to2) conflict (z/d -> y/d vs. x/d)
 test_setup_9h () {
-	test_create_repo 9h &&
+	git init 9h &&
 	(
 		cd 9h &&
 
@@ -3177,7 +3177,7 @@
 #       ERROR_MSG(untracked working tree files would be overwritten by merge)
 
 test_setup_10a () {
-	test_create_repo 10a &&
+	git init 10a &&
 	(
 		cd 10a &&
 
@@ -3243,7 +3243,7 @@
 #       ERROR_MSG(refusing to lose untracked file at 'y/d')
 
 test_setup_10b () {
-	test_create_repo 10b &&
+	git init 10b &&
 	(
 		cd 10b &&
 
@@ -3334,7 +3334,7 @@
 #             ERROR_MSG(Refusing to lose untracked file at y/c)
 
 test_setup_10c () {
-	test_create_repo 10c_$1 &&
+	git init 10c_$1 &&
 	(
 		cd 10c_$1 &&
 
@@ -3472,7 +3472,7 @@
 #             ERROR_MSG(Refusing to lose untracked file at y/wham)
 
 test_setup_10d () {
-	test_create_repo 10d &&
+	git init 10d &&
 	(
 		cd 10d &&
 
@@ -3568,7 +3568,7 @@
 #   Expected: y/{a,b,c} + untracked z/c
 
 test_setup_10e () {
-	test_create_repo 10e &&
+	git init 10e &&
 	(
 		cd 10e &&
 
@@ -3650,7 +3650,7 @@
 #             z/c with uncommitted mods on top of A:z/c_v1
 
 test_setup_11a () {
-	test_create_repo 11a &&
+	git init 11a &&
 	(
 		cd 11a &&
 
@@ -3728,7 +3728,7 @@
 
 
 test_setup_11b () {
-	test_create_repo 11b &&
+	git init 11b &&
 	(
 		cd 11b &&
 
@@ -3810,7 +3810,7 @@
 #             y/c left untouched (still has uncommitted mods)
 
 test_setup_11c () {
-	test_create_repo 11c &&
+	git init 11c &&
 	(
 		cd 11c &&
 
@@ -3883,7 +3883,7 @@
 #             y/{a,c~HEAD,c/d}, x/b, now-untracked z/c_v1 with uncommitted mods
 
 test_setup_11d () {
-	test_create_repo 11d &&
+	git init 11d &&
 	(
 		cd 11d &&
 
@@ -3968,7 +3968,7 @@
 #             y/c has dirty file from before merge
 
 test_setup_11e () {
-	test_create_repo 11e &&
+	git init 11e &&
 	(
 		cd 11e &&
 
@@ -4060,7 +4060,7 @@
 #             ERROR_MSG(Refusing to lose dirty file at y/wham)
 
 test_setup_11f () {
-	test_create_repo 11f &&
+	git init 11f &&
 	(
 		cd 11f &&
 
@@ -4155,7 +4155,7 @@
 #   Expected: node1/{leaf1,leaf2,leaf5,node2/{leaf3,leaf4,leaf6}}
 
 test_setup_12a () {
-	test_create_repo 12a &&
+	git init 12a &&
 	(
 		cd 12a &&
 
@@ -4238,7 +4238,7 @@
 #             node2/node1/{leaf1, leaf2}
 
 test_setup_12b1 () {
-	test_create_repo 12b1 &&
+	git init 12b1 &&
 	(
 		cd 12b1 &&
 
@@ -4327,7 +4327,7 @@
 #         even simple rules give weird results when given weird inputs.
 
 test_setup_12b2 () {
-	test_create_repo 12b2 &&
+	git init 12b2 &&
 	(
 		cd 12b2 &&
 
@@ -4402,7 +4402,7 @@
 #         each side of the merge.
 
 test_setup_12c1 () {
-	test_create_repo 12c1 &&
+	git init 12c1 &&
 	(
 		cd 12c1 &&
 
@@ -4492,7 +4492,7 @@
 #         on each side of the merge.
 
 test_setup_12c2 () {
-	test_create_repo 12c2 &&
+	git init 12c2 &&
 	(
 		cd 12c2 &&
 
@@ -4584,7 +4584,7 @@
 #   Expected: subdir/foo, bar
 
 test_setup_12d () {
-	test_create_repo 12d &&
+	git init 12d &&
 	(
 		cd 12d &&
 
@@ -4642,7 +4642,7 @@
 #   Expected: foo, bar
 
 test_setup_12e () {
-	test_create_repo 12e &&
+	git init 12e &&
 	(
 		cd 12e &&
 
@@ -4743,7 +4743,7 @@
 #      pick and re-applying them in the subsequent one.
 
 test_setup_12f () {
-	test_create_repo 12f &&
+	git init 12f &&
 	(
 		cd 12f &&
 
@@ -4902,7 +4902,7 @@
 #   Expected: newfile_{merged}, newdir/{a_B,b_B,c_A}
 
 test_setup_12g () {
-	test_create_repo 12g &&
+	git init 12g &&
 	(
 		cd 12g &&
 
@@ -4973,7 +4973,7 @@
 #   Expected: newdir/{alpha_2, b}
 
 test_setup_12h () {
-	test_create_repo 12h &&
+	git init 12h &&
 	(
 		cd 12h &&
 
@@ -5032,7 +5032,7 @@
 #                source/bar vs. source/subdir/bar
 
 test_setup_12i () {
-	test_create_repo 12i &&
+	git init 12i &&
 	(
 		cd 12i &&
 
@@ -5090,7 +5090,7 @@
 #   Expected: {foo, bar, baz_2}, with conflicts on bar vs. subdir/bar
 
 test_setup_12j () {
-	test_create_repo 12j &&
+	git init 12j &&
 	(
 		cd 12j &&
 
@@ -5148,7 +5148,7 @@
 #   Expected: dirA/{foo, bar, baz_2}, with conflicts on dirA/bar vs. dirB/bar
 
 test_setup_12k () {
-	test_create_repo 12k &&
+	git init 12k &&
 	(
 		cd 12k &&
 
@@ -5218,7 +5218,7 @@
 #   is needed for there to be a sub1/ -> sub3/ rename.
 
 test_setup_12l () {
-	test_create_repo 12l_$1 &&
+	git init 12l_$1 &&
 	(
 		cd 12l_$1 &&
 
@@ -5322,7 +5322,7 @@
 #   Expected: y/{b,c,d,e/f}, with notices/conflicts for both y/d and y/e/f
 
 test_setup_13a () {
-	test_create_repo 13a_$1 &&
+	git init 13a_$1 &&
 	(
 		cd 13a_$1 &&
 
@@ -5409,7 +5409,7 @@
 #             one about content, and one about file location
 
 test_setup_13b () {
-	test_create_repo 13b_$1 &&
+	git init 13b_$1 &&
 	(
 		cd 13b_$1 &&
 
@@ -5496,7 +5496,7 @@
 #             shown in testcase 13d.
 
 test_setup_13c () {
-	test_create_repo 13c_$1 &&
+	git init 13c_$1 &&
 	(
 		cd 13c_$1 &&
 
@@ -5584,7 +5584,7 @@
 #               No conflict in where a/y ends up, so put it in d/y.
 
 test_setup_13d () {
-	test_create_repo 13d_$1 &&
+	git init 13d_$1 &&
 	(
 		cd 13d_$1 &&
 
@@ -5710,7 +5710,7 @@
 #          least avoids hitting a BUG().
 #
 test_setup_13e () {
-	test_create_repo 13e &&
+	git init 13e &&
 	(
 		cd 13e &&
 
diff --git a/t/t6424-merge-unrelated-index-changes.sh b/t/t6424-merge-unrelated-index-changes.sh
index b6e424a..a61f20c 100755
--- a/t/t6424-merge-unrelated-index-changes.sh
+++ b/t/t6424-merge-unrelated-index-changes.sh
@@ -114,6 +114,39 @@
 	test_path_is_missing .git/MERGE_HEAD
 '
 
+test_expect_success 'resolve, trivial, related file removed' '
+	git reset --hard &&
+	git checkout B^0 &&
+
+	git rm a &&
+	test_path_is_missing a &&
+
+	test_must_fail git merge -s resolve C^0 &&
+
+	test_path_is_missing a &&
+	test_path_is_missing .git/MERGE_HEAD
+'
+
+test_expect_success 'resolve, non-trivial, related file removed' '
+	git reset --hard &&
+	git checkout B^0 &&
+
+	git rm a &&
+	test_path_is_missing a &&
+
+	# We also ask for recursive in order to turn off the "allow_trivial"
+	# setting in builtin/merge.c, and ensure that resolve really does
+	# correctly fail the merge (I guess this also tests that recursive
+	# correctly fails the merge, but the main thing we are attempting
+	# to test here is resolve and are just using the side effect of
+	# adding recursive to ensure that resolve is actually tested rather
+	# than the trivial merge codepath)
+	test_must_fail git merge -s resolve -s recursive D^0 &&
+
+	test_path_is_missing a &&
+	test_path_is_missing .git/MERGE_HEAD
+'
+
 test_expect_success 'recursive' '
 	git reset --hard &&
 	git checkout B^0 &&
@@ -242,4 +275,36 @@
 	test_path_is_missing .git/MERGE_HEAD
 '
 
+test_expect_success 'avoid failure due to stat-dirty files' '
+	git reset --hard &&
+	git checkout B^0 &&
+
+	# Make "a" be stat-dirty
+	test-tool chmtime =+1 a &&
+
+	# stat-dirty file should not prevent stash creation in builtin/merge.c
+	git merge -s resolve -s recursive D^0
+'
+
+test_expect_success 'with multiple strategies, recursive or ort failure do not early abort' '
+	git reset --hard &&
+	git checkout B^0 &&
+
+	test_seq 0 10 >a &&
+	git add a &&
+	git rev-parse :a >expect &&
+
+	sane_unset GIT_TEST_MERGE_ALGORITHM &&
+	test_must_fail git merge -s recursive -s ort -s octopus C^0 >output 2>&1 &&
+
+	grep "Trying merge strategy recursive..." output &&
+	grep "Trying merge strategy ort..." output &&
+	grep "Trying merge strategy octopus..." output &&
+	grep "No merge strategy handled the merge." output &&
+
+	# Changes to "a" should remain staged
+	git rev-parse :a >actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t6425-merge-rename-delete.sh b/t/t6425-merge-rename-delete.sh
index 459b431..93cd286 100755
--- a/t/t6425-merge-rename-delete.sh
+++ b/t/t6425-merge-rename-delete.sh
@@ -4,6 +4,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'rename/delete' '
diff --git a/t/t6426-merge-skip-unneeded-updates.sh b/t/t6426-merge-skip-unneeded-updates.sh
index 7b5f1c1..2bb8e7f 100755
--- a/t/t6426-merge-skip-unneeded-updates.sh
+++ b/t/t6426-merge-skip-unneeded-updates.sh
@@ -38,7 +38,7 @@
 #   Expected: b_2
 
 test_setup_1a () {
-	test_create_repo 1a_$1 &&
+	git init 1a_$1 &&
 	(
 		cd 1a_$1 &&
 
@@ -136,7 +136,7 @@
 #   Expected: c_2
 
 test_setup_2a () {
-	test_create_repo 2a_$1 &&
+	git init 2a_$1 &&
 	(
 		cd 2a_$1 &&
 
@@ -229,7 +229,7 @@
 #   Expected: c_2
 
 test_setup_2b () {
-	test_create_repo 2b_$1 &&
+	git init 2b_$1 &&
 	(
 		cd 2b_$1 &&
 
@@ -336,7 +336,7 @@
 #         not make that particular mistake.
 
 test_setup_2c () {
-	test_create_repo 2c &&
+	git init 2c &&
 	(
 		cd 2c &&
 
@@ -437,7 +437,7 @@
 #   Expected: bar/{bq_2, whatever}
 
 test_setup_3a () {
-	test_create_repo 3a_$1 &&
+	git init 3a_$1 &&
 	(
 		cd 3a_$1 &&
 
@@ -537,7 +537,7 @@
 #   Expected: bar/{bq_2, whatever}
 
 test_setup_3b () {
-	test_create_repo 3b_$1 &&
+	git init 3b_$1 &&
 	(
 		cd 3b_$1 &&
 
@@ -642,7 +642,7 @@
 #   Expected: b_2 for merge, b_4 in working copy
 
 test_setup_4a () {
-	test_create_repo 4a &&
+	git init 4a &&
 	(
 		cd 4a &&
 
@@ -714,7 +714,7 @@
 #   Expected: c_2
 
 test_setup_4b () {
-	test_create_repo 4b &&
+	git init 4b &&
 	(
 		cd 4b &&
 
diff --git a/t/t6427-diff3-conflict-markers.sh b/t/t6427-diff3-conflict-markers.sh
index a9ee4cb..dd5fe6a 100755
--- a/t/t6427-diff3-conflict-markers.sh
+++ b/t/t6427-diff3-conflict-markers.sh
@@ -19,7 +19,7 @@
 #
 
 test_expect_success 'setup no merge base' '
-	test_create_repo no_merge_base &&
+	git init no_merge_base &&
 	(
 		cd no_merge_base &&
 
@@ -55,7 +55,7 @@
 #
 
 test_expect_success 'setup unique merge base' '
-	test_create_repo unique_merge_base &&
+	git init unique_merge_base &&
 	(
 		cd unique_merge_base &&
 
@@ -116,7 +116,7 @@
 #
 
 test_expect_success 'setup multiple merge bases' '
-	test_create_repo multiple_merge_bases &&
+	git init multiple_merge_bases &&
 	(
 		cd multiple_merge_bases &&
 
@@ -190,7 +190,7 @@
 '
 
 test_expect_success 'rebase --merge describes parent of commit being picked' '
-	test_create_repo rebase &&
+	git init rebase &&
 	(
 		cd rebase &&
 		test_commit base file &&
@@ -212,7 +212,7 @@
 '
 
 test_setup_zdiff3 () {
-	test_create_repo zdiff3 &&
+	git init zdiff3 &&
 	(
 		cd zdiff3 &&
 
diff --git a/t/t6428-merge-conflicts-sparse.sh b/t/t6428-merge-conflicts-sparse.sh
index 064be1b..9919c3f 100755
--- a/t/t6428-merge-conflicts-sparse.sh
+++ b/t/t6428-merge-conflicts-sparse.sh
@@ -29,7 +29,7 @@
 # Testcase basic, conflicting changes in 'numerals'
 
 test_setup_numerals () {
-	test_create_repo numerals_$1 &&
+	git init numerals_$1 &&
 	(
 		cd numerals_$1 &&
 
diff --git a/t/t6429-merge-sequence-rename-caching.sh b/t/t6429-merge-sequence-rename-caching.sh
index e1ce919..d02fa16 100755
--- a/t/t6429-merge-sequence-rename-caching.sh
+++ b/t/t6429-merge-sequence-rename-caching.sh
@@ -35,7 +35,7 @@
 # preventing us from finding new renames.
 #
 test_expect_success 'caching renames does not preclude finding new ones' '
-	test_create_repo caching-renames-and-new-renames &&
+	git init caching-renames-and-new-renames &&
 	(
 		cd caching-renames-and-new-renames &&
 
@@ -106,7 +106,7 @@
 # should be able to only run rename detection on the upstream side one
 # time.)
 test_expect_success 'cherry-pick both a commit and its immediate revert' '
-	test_create_repo pick-commit-and-its-immediate-revert &&
+	git init pick-commit-and-its-immediate-revert &&
 	(
 		cd pick-commit-and-its-immediate-revert &&
 
@@ -162,7 +162,7 @@
 # could cause a spurious rename/add conflict.
 #
 test_expect_success 'rename same file identically, then reintroduce it' '
-	test_create_repo rename-rename-1to1-then-add-old-filename &&
+	git init rename-rename-1to1-then-add-old-filename &&
 	(
 		cd rename-rename-1to1-then-add-old-filename &&
 
@@ -229,7 +229,7 @@
 # cached, the directory rename could put newfile in the wrong directory.
 #
 test_expect_success 'rename same file identically, then add file to old dir' '
-	test_create_repo rename-rename-1to1-then-add-file-to-old-dir &&
+	git init rename-rename-1to1-then-add-file-to-old-dir &&
 	(
 		cd rename-rename-1to1-then-add-file-to-old-dir &&
 
@@ -311,7 +311,7 @@
 # should avoid the need to re-detect upstream renames.)
 #
 test_expect_success 'cached dir rename does not prevent noticing later conflict' '
-	test_create_repo dir-rename-cache-not-occluding-later-conflict &&
+	git init dir-rename-cache-not-occluding-later-conflict &&
 	(
 		cd dir-rename-cache-not-occluding-later-conflict &&
 
@@ -365,7 +365,7 @@
 
 # Helper for the next two tests
 test_setup_upstream_rename () {
-	test_create_repo $1 &&
+	git init $1 &&
 	(
 		cd $1 &&
 
@@ -537,7 +537,7 @@
 
 # Helper for the next two tests
 test_setup_topic_rename () {
-	test_create_repo $1 &&
+	git init $1 &&
 	(
 		cd $1 &&
 
@@ -725,7 +725,7 @@
 		mkdir unrelated &&
 		for i in $(test_seq 1 10)
 		do
-			>unrelated/$i
+			>unrelated/$i || exit 1
 		done &&
 		test_seq  2 10 >numbers &&
 		test_seq 12 20 >values &&
diff --git a/t/t6431-merge-criscross.sh b/t/t6431-merge-criscross.sh
index 3824756..3fe14cd 100755
--- a/t/t6431-merge-criscross.sh
+++ b/t/t6431-merge-criscross.sh
@@ -2,6 +2,7 @@
 
 test_description='merge-recursive backend test'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 #         A      <- create some files
diff --git a/t/t6435-merge-sparse.sh b/t/t6435-merge-sparse.sh
index 74562e1..fde4aa3 100755
--- a/t/t6435-merge-sparse.sh
+++ b/t/t6435-merge-sparse.sh
@@ -2,6 +2,7 @@
 
 test_description='merge with sparse files'
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 # test_file $filename $content
@@ -26,6 +27,7 @@
 	git rm modify_delete &&
 	test_commit_this ours &&
 	git config core.sparseCheckout true &&
+	mkdir .git/info &&
 	echo "/checked-out" >.git/info/sparse-checkout &&
 	git reset --hard &&
 	test_must_fail git merge theirs
diff --git a/t/t6437-submodule-merge.sh b/t/t6437-submodule-merge.sh
index 178413c..c9a86f2 100755
--- a/t/t6437-submodule-merge.sh
+++ b/t/t6437-submodule-merge.sh
@@ -103,8 +103,25 @@
 	 echo "file-c" > file-c &&
 	 git add file-c &&
 	 git commit -m "sub-c") &&
-	git commit -a -m "c" &&
+	git commit -a -m "c")
+'
 
+test_expect_success 'merging should conflict for non fast-forward' '
+	test_when_finished "git -C merge-search reset --hard" &&
+	(cd merge-search &&
+	 git checkout -b test-nonforward-a b &&
+	  if test "$GIT_TEST_MERGE_ALGORITHM" = ort
+	  then
+		test_must_fail git merge c >actual &&
+		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
+		grep "$sub_expect" actual
+	  else
+		test_must_fail git merge c 2> actual
+	  fi)
+'
+
+test_expect_success 'finish setup for merge-search' '
+	(cd merge-search &&
 	git checkout -b d a &&
 	(cd sub &&
 	 git checkout -b sub-d sub-b &&
@@ -129,14 +146,16 @@
 	 test_cmp expect actual)
 '
 
-test_expect_success 'merging should conflict for non fast-forward' '
+test_expect_success 'merging should conflict for non fast-forward (resolution exists)' '
 	(cd merge-search &&
-	 git checkout -b test-nonforward b &&
+	 git checkout -b test-nonforward-b b &&
 	 (cd sub &&
-	  git rev-parse sub-d > ../expect) &&
+	  git rev-parse --short sub-d > ../expect) &&
 	  if test "$GIT_TEST_MERGE_ALGORITHM" = ort
 	  then
-		test_must_fail git merge c >actual
+		test_must_fail git merge c >actual &&
+		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
+		grep "$sub_expect" actual
 	  else
 		test_must_fail git merge c 2> actual
 	  fi &&
@@ -161,7 +180,9 @@
 	 ) &&
 	 if test "$GIT_TEST_MERGE_ALGORITHM" = ort
 	 then
-		test_must_fail git merge c >actual
+		test_must_fail git merge c >actual &&
+		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-c)" &&
+		grep "$sub_expect" actual
 	 else
 		test_must_fail git merge c 2> actual
 	 fi &&
@@ -205,7 +226,12 @@
 	git commit -a -m "f" &&
 
 	git checkout -b test-backward e &&
-	test_must_fail git merge f)
+	test_must_fail git merge f >actual &&
+	if test "$GIT_TEST_MERGE_ALGORITHM" = ort
+    then
+		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short sub-d)" &&
+		grep "$sub_expect" actual
+	fi)
 '
 
 
@@ -310,7 +336,7 @@
 #   Expected: path/ is submodule and file contents for B's path are somewhere
 
 test_expect_success 'setup file/submodule conflict' '
-	test_create_repo file-submodule &&
+	git init file-submodule &&
 	(
 		cd file-submodule &&
 
@@ -325,7 +351,7 @@
 		git commit -m B &&
 
 		git checkout A &&
-		test_create_repo path &&
+		git init path &&
 		test_commit -C path world &&
 		git submodule add ./path &&
 		git commit -m A
@@ -385,7 +411,7 @@
 #     under the submodule to be treated as untracked or in the way.
 
 test_expect_success 'setup directory/submodule conflict' '
-	test_create_repo directory-submodule &&
+	git init directory-submodule &&
 	(
 		cd directory-submodule &&
 
@@ -408,7 +434,7 @@
 		git commit -m B2 &&
 
 		git checkout A &&
-		test_create_repo path &&
+		git init path &&
 		test_commit -C path hello world &&
 		git submodule add ./path &&
 		git commit -m A
@@ -476,4 +502,44 @@
 	)
 '
 
+# Setup:
+#   - Submodule has 2 commits: a and b
+#   - Superproject branch 'a' adds and commits submodule pointing to 'commit a'
+#   - Superproject branch 'b' adds and commits submodule pointing to 'commit b'
+# If these two branches are now merged, there is no merge base
+test_expect_success 'setup for null merge base' '
+	mkdir no-merge-base &&
+	(cd no-merge-base &&
+	git init &&
+	mkdir sub &&
+	(cd sub &&
+	 git init &&
+	 echo "file-a" > file-a &&
+	 git add file-a &&
+	 git commit -m "commit a") &&
+	git commit --allow-empty -m init &&
+	git branch init &&
+	git checkout -b a init &&
+	git add sub &&
+	git commit -m "a" &&
+	git switch main &&
+	(cd sub &&
+	 echo "file-b" > file-b &&
+	 git add file-b &&
+	 git commit -m "commit b"))
+'
+
+test_expect_success 'merging should fail with no merge base' '
+	(cd no-merge-base &&
+	git checkout -b b init &&
+	git add sub &&
+	git commit -m "b" &&
+	test_must_fail git merge a >actual &&
+	if test "$GIT_TEST_MERGE_ALGORITHM" = ort
+    then
+		sub_expect="go to submodule (sub), and either merge commit $(git -C sub rev-parse --short HEAD^1)" &&
+		grep "$sub_expect" actual
+	fi)
+'
+
 test_done
diff --git a/t/t6439-merge-co-error-msgs.sh b/t/t6439-merge-co-error-msgs.sh
index 5bfb027..52cf0c8 100755
--- a/t/t6439-merge-co-error-msgs.sh
+++ b/t/t6439-merge-co-error-msgs.sh
@@ -47,6 +47,7 @@
 		export GIT_MERGE_VERBOSITY &&
 		test_must_fail git merge branch 2>out2
 	) &&
+	echo "Merge with strategy ${GIT_TEST_MERGE_ALGORITHM:-ort} failed." >>expect &&
 	test_cmp out2 expect &&
 	git reset --hard HEAD^
 '
diff --git a/t/t7002-mv-sparse-checkout.sh b/t/t7002-mv-sparse-checkout.sh
index f0f7cbf..71fe296 100755
--- a/t/t7002-mv-sparse-checkout.sh
+++ b/t/t7002-mv-sparse-checkout.sh
@@ -4,6 +4,18 @@
 
 . ./test-lib.sh
 
+setup_sparse_checkout () {
+	mkdir folder1 &&
+	touch folder1/file1 &&
+	git add folder1 &&
+	git sparse-checkout set --cone sub
+}
+
+cleanup_sparse_checkout () {
+	git sparse-checkout disable &&
+	git reset --hard
+}
+
 test_expect_success 'setup' "
 	mkdir -p sub/dir sub/dir2 &&
 	touch a b c sub/d sub/dir/e sub/dir2/e &&
@@ -196,6 +208,7 @@
 '
 
 test_expect_success 'refuse to move file to non-skip-worktree sparse path' '
+	test_when_finished "cleanup_sparse_checkout" &&
 	git reset --hard &&
 	git sparse-checkout init --no-cone &&
 	git sparse-checkout set a !/x y/ !x/y/z &&
@@ -206,4 +219,75 @@
 	test_cmp expect stderr
 '
 
+test_expect_success 'refuse to move out-of-cone directory without --sparse' '
+	test_when_finished "cleanup_sparse_checkout" &&
+	setup_sparse_checkout &&
+
+	test_must_fail git mv folder1 sub 2>stderr &&
+	cat sparse_error_header >expect &&
+	echo folder1/file1 >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr
+'
+
+test_expect_success 'can move out-of-cone directory with --sparse' '
+	test_when_finished "cleanup_sparse_checkout" &&
+	setup_sparse_checkout &&
+
+	git mv --sparse folder1 sub 2>stderr &&
+	test_must_be_empty stderr &&
+
+	test_path_is_dir sub/folder1 &&
+	test_path_is_file sub/folder1/file1
+'
+
+test_expect_success 'refuse to move out-of-cone file without --sparse' '
+	test_when_finished "cleanup_sparse_checkout" &&
+	setup_sparse_checkout &&
+
+	test_must_fail git mv folder1/file1 sub 2>stderr &&
+	cat sparse_error_header >expect &&
+	echo folder1/file1 >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr
+'
+
+test_expect_success 'can move out-of-cone file with --sparse' '
+	test_when_finished "cleanup_sparse_checkout" &&
+	setup_sparse_checkout &&
+
+	git mv --sparse folder1/file1 sub 2>stderr &&
+	test_must_be_empty stderr &&
+
+	test_path_is_file sub/file1
+'
+
+test_expect_success 'refuse to move sparse file to existing destination' '
+	test_when_finished "cleanup_sparse_checkout" &&
+	mkdir folder1 &&
+	touch folder1/file1 &&
+	touch sub/file1 &&
+	git add folder1 sub/file1 &&
+	git sparse-checkout set --cone sub &&
+
+	test_must_fail git mv --sparse folder1/file1 sub 2>stderr &&
+	echo "fatal: destination exists, source=folder1/file1, destination=sub/file1" >expect &&
+	test_cmp expect stderr
+'
+
+test_expect_success 'move sparse file to existing destination with --force and --sparse' '
+	test_when_finished "cleanup_sparse_checkout" &&
+	mkdir folder1 &&
+	touch folder1/file1 &&
+	touch sub/file1 &&
+	echo "overwrite" >folder1/file1 &&
+	git add folder1 sub/file1 &&
+	git sparse-checkout set --cone sub &&
+
+	git mv --sparse --force folder1/file1 sub 2>stderr &&
+	test_must_be_empty stderr &&
+	echo "overwrite" >expect &&
+	test_cmp expect sub/file1
+'
+
 test_done
diff --git a/t/t7007-show.sh b/t/t7007-show.sh
index d6cc69e..f908a4d 100755
--- a/t/t7007-show.sh
+++ b/t/t7007-show.sh
@@ -2,6 +2,7 @@
 
 test_description='git show'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t7060-wtstatus.sh b/t/t7060-wtstatus.sh
index 0f4344c..aaeb4a5 100755
--- a/t/t7060-wtstatus.sh
+++ b/t/t7060-wtstatus.sh
@@ -5,6 +5,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t7062-wtstatus-ignorecase.sh b/t/t7062-wtstatus-ignorecase.sh
index 73709db..caf372a 100755
--- a/t/t7062-wtstatus-ignorecase.sh
+++ b/t/t7062-wtstatus-ignorecase.sh
@@ -2,6 +2,7 @@
 
 test_description='git-status with core.ignorecase=true'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'status with hash collisions' '
diff --git a/t/t7063-status-untracked-cache.sh b/t/t7063-status-untracked-cache.sh
index c1f0d95..8929ef4 100755
--- a/t/t7063-status-untracked-cache.sh
+++ b/t/t7063-status-untracked-cache.sh
@@ -86,7 +86,7 @@
 '
 
 test_expect_success 'setup' '
-	git init worktree &&
+	git init --template= worktree &&
 	cd worktree &&
 	mkdir done dtwo dthree &&
 	touch one two three done/one dtwo/two dthree/three &&
@@ -94,6 +94,7 @@
 	test-tool chmtime =-300 done dtwo dthree &&
 	test-tool chmtime =-300 . &&
 	git add one two done/one &&
+	mkdir .git/info &&
 	: >.git/info/exclude &&
 	git update-index --untracked-cache &&
 	test_oid_cache <<-EOF
diff --git a/t/t7110-reset-merge.sh b/t/t7110-reset-merge.sh
index 3d62e10..eb881be 100755
--- a/t/t7110-reset-merge.sh
+++ b/t/t7110-reset-merge.sh
@@ -5,6 +5,7 @@
 
 test_description='Tests for "git reset" with "--merge" and "--keep" options'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t7111-reset-table.sh b/t/t7111-reset-table.sh
index ce421ad..78f25c1 100755
--- a/t/t7111-reset-table.sh
+++ b/t/t7111-reset-table.sh
@@ -5,6 +5,7 @@
 
 test_description='Tests to check that "reset" options follow a known table'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index e7cec2e..b50db3f 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -14,6 +14,32 @@
 
 . ./test-lib.sh
 
+test_expect_success 'submodule usage: -h' '
+	git submodule -h >out 2>err &&
+	grep "^usage: git submodule" out &&
+	test_must_be_empty err
+'
+
+test_expect_success 'submodule usage: --recursive' '
+	test_expect_code 1 git submodule --recursive >out 2>err &&
+	grep "^usage: git submodule" err &&
+	test_must_be_empty out
+'
+
+test_expect_success 'submodule usage: status --' '
+	test_expect_code 1 git submodule -- &&
+	test_expect_code 1 git submodule --end-of-options
+'
+
+for opt in '--quiet' '--cached'
+do
+	test_expect_success "submodule usage: status $opt" '
+		git submodule $opt &&
+		git submodule status $opt &&
+		git submodule $opt status
+	'
+done
+
 test_expect_success 'submodule deinit works on empty repository' '
 	git submodule deinit --all
 '
@@ -152,6 +178,11 @@
 	test_must_be_empty untracked
 '
 
+test_expect_success !WINDOWS 'submodule add (absolute path)' '
+	test_when_finished "git reset --hard" &&
+	git submodule add "$submodurl" "$submodurl/add-abs"
+'
+
 test_expect_success 'setup parent and one repository' '
 	test_create_repo parent &&
 	test_commit -C parent one
@@ -1224,31 +1255,6 @@
 	)
 '
 
-test_expect_success 'submodule helper list is not confused by common prefixes' '
-	mkdir -p dir1/b &&
-	(
-		cd dir1/b &&
-		git init &&
-		echo hi >testfile2 &&
-		git add . &&
-		git commit -m "test1"
-	) &&
-	mkdir -p dir2/b &&
-	(
-		cd dir2/b &&
-		git init &&
-		echo hello >testfile1 &&
-		git add .  &&
-		git commit -m "test2"
-	) &&
-	git submodule add /dir1/b dir1/b &&
-	git submodule add /dir2/b dir2/b &&
-	git commit -m "first submodule commit" &&
-	git submodule--helper list dir1/b | cut -f 2 >actual &&
-	echo "dir1/b" >expect &&
-	test_cmp expect actual
-'
-
 test_expect_success 'setup superproject with submodules' '
 	git init sub1 &&
 	test_commit -C sub1 test &&
diff --git a/t/t7401-submodule-summary.sh b/t/t7401-submodule-summary.sh
index 9c3cc4c..542b333 100755
--- a/t/t7401-submodule-summary.sh
+++ b/t/t7401-submodule-summary.sh
@@ -17,6 +17,7 @@
 # various reasons, one of them being that there are lots of commands taking place
 # outside of 'test_expect_success' block, which is no longer in good-style.
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 add_file () {
diff --git a/t/t7402-submodule-rebase.sh b/t/t7402-submodule-rebase.sh
index 8e32f19..ebeca12 100755
--- a/t/t7402-submodule-rebase.sh
+++ b/t/t7402-submodule-rebase.sh
@@ -104,7 +104,7 @@
 	test_tick &&
 	git commit -m fourth &&
 
-	test_must_fail git rebase --onto HEAD^^ HEAD^ HEAD^0 &&
+	test_must_fail git rebase --onto HEAD^^ HEAD^ HEAD^0 >actual_output &&
 	git ls-files -s submodule >actual &&
 	(
 		cd submodule &&
@@ -112,7 +112,12 @@
 		echo "160000 $(git rev-parse HEAD^^) 2	submodule" &&
 		echo "160000 $(git rev-parse HEAD) 3	submodule"
 	) >expect &&
-	test_cmp expect actual
+	test_cmp expect actual &&
+	if test "$GIT_TEST_MERGE_ALGORITHM" = ort
+    then
+		sub_expect="go to submodule (submodule), and either merge commit $(git -C submodule rev-parse --short HEAD^0)" &&
+		grep "$sub_expect" actual_output
+	fi
 '
 
 test_done
diff --git a/t/t7406-submodule-update.sh b/t/t7406-submodule-update.sh
index 43f779d..c5f5dbe 100755
--- a/t/t7406-submodule-update.sh
+++ b/t/t7406-submodule-update.sh
@@ -769,7 +769,7 @@
 	   echo "" > file
 	  )
 	 ) &&
-	 test_must_fail git submodule update --recursive &&
+	 test_expect_code 1 git submodule update --recursive &&
 	 (cd submodule2 &&
 	  git rev-parse --verify HEAD >../actual
 	 ) &&
@@ -1074,7 +1074,7 @@
 	 git submodule update --rebase --quiet >out 2>err &&
 	 test_must_be_empty out &&
 	 test_must_be_empty err &&
-	 git submodule update --rebase -v >out 2>err &&
+	 git submodule update --rebase >out 2>err &&
 	 test_file_not_empty out &&
 	 test_must_be_empty err
 	)
@@ -1116,4 +1116,66 @@
 	test_cmp_config -C super-filter/submodule blob:none remote.origin.partialclonefilter
 '
 
+# NEEDSWORK: Clean up the tests so that we can reuse the test setup.
+# Don't reuse the existing repos because the earlier tests have
+# intentionally disruptive configurations.
+test_expect_success 'setup clean recursive superproject' '
+	git init bottom &&
+	test_commit -C bottom "bottom" &&
+	git init middle &&
+	git -C middle submodule add ../bottom bottom &&
+	git -C middle commit -m "middle" &&
+	git init top &&
+	git -C top submodule add ../middle middle &&
+	git -C top commit -m "top" &&
+	git clone --recurse-submodules top top-clean
+'
+
+test_expect_success 'submodule update should skip unmerged submodules' '
+	test_when_finished "rm -fr top-cloned" &&
+	cp -r top-clean top-cloned &&
+
+	# Create an upstream commit in each repo, starting with bottom
+	test_commit -C bottom upstream_commit &&
+	# Create middle commit
+	git -C middle/bottom fetch &&
+	git -C middle/bottom checkout -f FETCH_HEAD &&
+	git -C middle add bottom &&
+	git -C middle commit -m "upstream_commit" &&
+	# Create top commit
+	git -C top/middle fetch &&
+	git -C top/middle checkout -f FETCH_HEAD &&
+	git -C top add middle &&
+	git -C top commit -m "upstream_commit" &&
+
+	# Create a downstream conflict
+	test_commit -C top-cloned/middle/bottom downstream_commit &&
+	git -C top-cloned/middle add bottom &&
+	git -C top-cloned/middle commit -m "downstream_commit" &&
+	git -C top-cloned/middle fetch --recurse-submodules origin &&
+	test_must_fail git -C top-cloned/middle merge origin/main &&
+
+	# Make the update of "middle" a no-op, otherwise we error out
+	# because of its unmerged state
+	test_config -C top-cloned submodule.middle.update !true &&
+	git -C top-cloned submodule update --recursive 2>actual.err &&
+	cat >expect.err <<-\EOF &&
+	Skipping unmerged submodule middle/bottom
+	EOF
+	test_cmp expect.err actual.err
+'
+
+test_expect_success 'submodule update --recursive skip submodules with strategy=none' '
+	test_when_finished "rm -fr top-cloned" &&
+	cp -r top-clean top-cloned &&
+
+	test_commit -C top-cloned/middle/bottom downstream_commit &&
+	git -C top-cloned/middle config submodule.bottom.update none &&
+	git -C top-cloned submodule update --recursive 2>actual.err &&
+	cat >expect.err <<-\EOF &&
+	Skipping submodule '\''middle/bottom'\''
+	EOF
+	test_cmp expect.err actual.err
+'
+
 test_done
diff --git a/t/t7412-submodule-absorbgitdirs.sh b/t/t7412-submodule-absorbgitdirs.sh
index 1cfa150..2859695 100755
--- a/t/t7412-submodule-absorbgitdirs.sh
+++ b/t/t7412-submodule-absorbgitdirs.sh
@@ -6,6 +6,7 @@
 directory into the superproject.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup a real submodule' '
diff --git a/t/t7413-submodule-is-active.sh b/t/t7413-submodule-is-active.sh
index c8e7e98..4dc7d08 100755
--- a/t/t7413-submodule-is-active.sh
+++ b/t/t7413-submodule-is-active.sh
@@ -1,11 +1,15 @@
 #!/bin/sh
 
-test_description='Test submodule--helper is-active
+test_description='Test with test-tool submodule is-active
 
-This test verifies that `git submodue--helper is-active` correctly identifies
+This test verifies that `test-tool submodule is-active` correctly identifies
 submodules which are "active" and interesting to the user.
+
+This is a unit test of the submodule.c is_submodule_active() function,
+which is also indirectly tested elsewhere.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
@@ -25,13 +29,13 @@
 '
 
 test_expect_success 'is-active works with urls' '
-	git -C super submodule--helper is-active sub1 &&
-	git -C super submodule--helper is-active sub2 &&
+	test-tool -C super submodule is-active sub1 &&
+	test-tool -C super submodule is-active sub2 &&
 
 	git -C super config --unset submodule.sub1.URL &&
-	test_must_fail git -C super submodule--helper is-active sub1 &&
+	test_must_fail test-tool -C super submodule is-active sub1 &&
 	git -C super config submodule.sub1.URL ../sub &&
-	git -C super submodule--helper is-active sub1
+	test-tool -C super submodule is-active sub1
 '
 
 test_expect_success 'is-active works with submodule.<name>.active config' '
@@ -39,11 +43,11 @@
 	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 &&
+	test_must_fail test-tool -C super submodule 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-tool -C super submodule is-active sub1
 '
 
 test_expect_success 'is-active works with basic submodule.active config' '
@@ -53,17 +57,17 @@
 	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-tool -C super submodule is-active sub1 &&
+	test-tool -C super submodule 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 &&
+	test_must_fail test-tool -C super submodule 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_must_fail test-tool -C super submodule is-active not-a-submodule
 '
 
 test_expect_success 'is-active works with exclusions in submodule.active config' '
@@ -72,8 +76,8 @@
 	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_must_fail test-tool -C super submodule is-active sub1 &&
+	test-tool -C super submodule is-active sub2
 '
 
 test_expect_success 'is-active with submodule.active and submodule.<name>.active' '
@@ -85,8 +89,8 @@
 	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_must_fail test-tool -C super submodule is-active sub1 &&
+	test-tool -C super submodule is-active sub2
 '
 
 test_expect_success 'is-active, submodule.active and submodule add' '
diff --git a/t/t7414-submodule-mistakes.sh b/t/t7414-submodule-mistakes.sh
index f2e7df5..3269298 100755
--- a/t/t7414-submodule-mistakes.sh
+++ b/t/t7414-submodule-mistakes.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='handling of common mistakes people may make with submodules'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'create embedded repository' '
diff --git a/t/t7418-submodule-sparse-gitmodules.sh b/t/t7418-submodule-sparse-gitmodules.sh
index f87e524..57d7ab3 100755
--- a/t/t7418-submodule-sparse-gitmodules.sh
+++ b/t/t7418-submodule-sparse-gitmodules.sh
@@ -31,8 +31,9 @@
 		test_tick &&
 		git commit -m "Add submodule"
 	) &&
-	git clone upstream super &&
+	git clone --template= upstream super &&
 	(cd super &&
+		mkdir .git/info &&
 		cat >.git/info/sparse-checkout <<-\EOF &&
 		/*
 		!/.gitmodules
diff --git a/t/t7419-submodule-set-branch.sh b/t/t7419-submodule-set-branch.sh
index 3b925c3..96e9842 100755
--- a/t/t7419-submodule-set-branch.sh
+++ b/t/t7419-submodule-set-branch.sh
@@ -9,6 +9,7 @@
 as expected.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 TEST_NO_CREATE_REPO=1
 . ./test-lib.sh
 
diff --git a/t/t7450-bad-git-dotfiles.sh b/t/t7450-bad-git-dotfiles.sh
index 41706c1..2c24f12 100755
--- a/t/t7450-bad-git-dotfiles.sh
+++ b/t/t7450-bad-git-dotfiles.sh
@@ -21,7 +21,7 @@
 	valid/with/paths
 	EOF
 
-	git submodule--helper check-name >actual <<-\EOF &&
+	test-tool submodule check-name >actual <<-\EOF &&
 	valid
 	valid/with/paths
 
diff --git a/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh b/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh
index ad1eb64..aa004b7 100755
--- a/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh
+++ b/t/t7503-pre-commit-and-pre-merge-commit-hooks.sh
@@ -5,6 +5,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'root commit' '
diff --git a/t/t7506-status-submodule.sh b/t/t7506-status-submodule.sh
index 3fcb447..f5426a8 100755
--- a/t/t7506-status-submodule.sh
+++ b/t/t7506-status-submodule.sh
@@ -2,6 +2,7 @@
 
 test_description='git status for submodule'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_create_repo_with_commit () {
diff --git a/t/t7507-commit-verbose.sh b/t/t7507-commit-verbose.sh
index ed2653d..92462a2 100755
--- a/t/t7507-commit-verbose.sh
+++ b/t/t7507-commit-verbose.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='verbose commit template'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 write_script "check-for-diff" <<\EOF &&
diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
index f0f6fda..7c3f6ed 100755
--- a/t/t7600-merge.sh
+++ b/t/t7600-merge.sh
@@ -255,6 +255,15 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'merge --squash --autostash conflict does not attempt to apply autostash' '
+	git reset --hard c3 &&
+	>unrelated &&
+	git add unrelated &&
+	test_must_fail git merge --squash c7 --autostash >out 2>err &&
+	! grep "Applying autostash resulted in conflicts." err &&
+	grep "When finished, apply stashed changes with \`git stash pop\`" out
+'
+
 test_expect_success 'merge c3 with c7 with commit.cleanup = scissors' '
 	git config commit.cleanup scissors &&
 	git reset --hard c3 &&
diff --git a/t/t7607-merge-state.sh b/t/t7607-merge-state.sh
new file mode 100755
index 0000000..89a62ac
--- /dev/null
+++ b/t/t7607-merge-state.sh
@@ -0,0 +1,32 @@
+#!/bin/sh
+
+test_description="Test that merge state is as expected after failed merge"
+
+GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
+export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+. ./test-lib.sh
+
+test_expect_success 'Ensure we restore original state if no merge strategy handles it' '
+	test_commit --no-tag "Initial" base base &&
+
+	for b in branch1 branch2 branch3
+	do
+		git checkout -b $b main &&
+		test_commit --no-tag "Change on $b" base $b || return 1
+	done &&
+
+	git checkout branch1 &&
+	# This is a merge that octopus cannot handle.  Note, that it does not
+	# just hit conflicts, it completely fails and says that it cannot
+	# handle this type of merge.
+	test_expect_code 2 git merge branch2 branch3 >output 2>&1 &&
+	grep "fatal: merge program failed" output &&
+	grep "Should not be doing an octopus" output &&
+
+	# Make sure we did not leave stray changes around when no appropriate
+	# merge strategy was found
+	git diff --exit-code --name-status &&
+	test_path_is_missing .git/MERGE_HEAD
+'
+
+test_done
diff --git a/t/t7609-mergetool--lib.sh b/t/t7609-mergetool--lib.sh
index 330d6d6..8b1c3bd 100755
--- a/t/t7609-mergetool--lib.sh
+++ b/t/t7609-mergetool--lib.sh
@@ -4,6 +4,7 @@
 
 Testing basic merge tools options'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'mergetool --tool=vimdiff creates the expected layout' '
diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 6935601..0f93799 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh
@@ -77,6 +77,7 @@
 	# Say hello.
 	function hello() {
 	  echo "Hello world."
+	  echo "Hello again."
 	} # hello
 
 	# Still a no-op.
@@ -595,6 +596,92 @@
 	test_must_be_empty actual
 '
 
+test_expect_success 'grep --max-count 0 (must exit with non-zero)' '
+	test_must_fail git grep --max-count 0 foo >actual &&
+	test_must_be_empty actual
+'
+
+test_expect_success 'grep --max-count 3' '
+	cat >expected <<-EOF &&
+	file:foo mmap bar
+	file:foo_mmap bar
+	file:foo_mmap bar mmap
+	EOF
+	git grep --max-count 3 foo >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'grep --max-count -1 (no limit)' '
+	cat >expected <<-EOF &&
+	file:foo mmap bar
+	file:foo_mmap bar
+	file:foo_mmap bar mmap
+	file:foo mmap bar_mmap
+	file:foo_mmap bar mmap baz
+	EOF
+	git grep --max-count -1 foo >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'grep --max-count 1 --context 2' '
+	cat >expected <<-EOF &&
+	file-foo mmap bar
+	file:foo_mmap bar
+	file-foo_mmap bar mmap
+	EOF
+	git grep --max-count 1 --context 1 foo_mmap >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'grep --max-count 1 --show-function' '
+	cat >expected <<-EOF &&
+	hello.ps1=function hello() {
+	hello.ps1:  echo "Hello world."
+	EOF
+	git grep --max-count 1 --show-function Hello hello.ps1 >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'grep --max-count 2 --show-function' '
+	cat >expected <<-EOF &&
+	hello.ps1=function hello() {
+	hello.ps1:  echo "Hello world."
+	hello.ps1:  echo "Hello again."
+	EOF
+	git grep --max-count 2 --show-function Hello hello.ps1 >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'grep --max-count 1 --count' '
+	cat >expected <<-EOF &&
+	hello.ps1:1
+	EOF
+	git grep --max-count 1 --count Hello hello.ps1 >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'grep --max-count 1 (multiple files)' '
+	cat >expected <<-EOF &&
+	hello.c:#include <stdio.h>
+	hello.ps1:# No-op.
+	EOF
+	git grep --max-count 1 -e o -- hello.\* >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'grep --max-count 1 --context 1 (multiple files)' '
+	cat >expected <<-EOF &&
+	hello.c-#include <assert.h>
+	hello.c:#include <stdio.h>
+	hello.c-
+	--
+	hello.ps1:# No-op.
+	hello.ps1-function dummy() {}
+	EOF
+	git grep --max-count 1 --context 1 -e o -- hello.\* >actual &&
+	test_cmp expected actual
+'
+
 cat >expected <<EOF
 file:foo mmap bar_mmap
 EOF
diff --git a/t/t7812-grep-icase-non-ascii.sh b/t/t7812-grep-icase-non-ascii.sh
index ac7be54..31c66b6 100755
--- a/t/t7812-grep-icase-non-ascii.sh
+++ b/t/t7812-grep-icase-non-ascii.sh
@@ -2,6 +2,7 @@
 
 test_description='grep icase on non-English locales'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./lib-gettext.sh
 
 doalarm () {
diff --git a/t/t7814-grep-recurse-submodules.sh b/t/t7814-grep-recurse-submodules.sh
index a4476dc..3ad8052 100755
--- a/t/t7814-grep-recurse-submodules.sh
+++ b/t/t7814-grep-recurse-submodules.sh
@@ -6,6 +6,7 @@
 submodules.
 '
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB=1
@@ -471,8 +472,10 @@
 test_expect_failure 'grep --textconv: superproject .git/info/attributes does not affect submodules' '
 	reset_and_clean &&
 	test_config_global diff.d2x.textconv "sed -e \"s/d/x/\"" &&
-	super_attr="$(git rev-parse --git-path info/attributes)" &&
+	super_info="$(git rev-parse --git-path info)" &&
+	super_attr="$super_info/attributes" &&
 	test_when_finished "rm -f \"$super_attr\"" &&
+	mkdir "$super_info" &&
 	echo "a diff=d2x" >"$super_attr" &&
 
 	cat >expect <<-\EOF &&
@@ -516,7 +519,8 @@
 	reset_and_clean &&
 	test_config_global diff.d2x.textconv "sed -e \"s/d/x/\"" &&
 
-	submodule_attr="$(git -C submodule rev-parse --path-format=absolute --git-path info/attributes)" &&
+	submodule_info="$(git -C submodule rev-parse --path-format=absolute --git-path info)" &&
+	submodule_attr="$submodule_info/attributes" &&
 	test_when_finished "rm -f \"$submodule_attr\"" &&
 	echo "a diff=d2x" >"$submodule_attr" &&
 
diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index 74aa638..2724a44 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -32,11 +32,13 @@
 }
 
 test_expect_success 'help text' '
-	test_expect_code 129 git maintenance -h 2>err &&
-	test_i18ngrep "usage: git maintenance <subcommand>" err &&
-	test_expect_code 128 git maintenance barf 2>err &&
-	test_i18ngrep "invalid subcommand: barf" err &&
+	test_expect_code 129 git maintenance -h >actual &&
+	test_i18ngrep "usage: git maintenance <subcommand>" actual &&
+	test_expect_code 129 git maintenance barf 2>err &&
+	test_i18ngrep "unknown subcommand: \`barf'\''" err &&
+	test_i18ngrep "usage: git maintenance" err &&
 	test_expect_code 129 git maintenance 2>err &&
+	test_i18ngrep "error: need a subcommand" err &&
 	test_i18ngrep "usage: git maintenance" err
 '
 
@@ -162,7 +164,6 @@
 	test_cmp_rev refs/remotes/remote1/one refs/prefetch/remotes/remote1/one &&
 	test_cmp_rev refs/remotes/remote2/two refs/prefetch/remotes/remote2/two &&
 
-	test_cmp_config refs/prefetch/ log.excludedecoration &&
 	git log --oneline --decorate --all >log &&
 	! grep "prefetch" log &&
 
@@ -173,26 +174,6 @@
 	test_subcommand git fetch remote2 $fetchargs <skip-remote1.txt
 '
 
-test_expect_success 'prefetch and existing log.excludeDecoration values' '
-	git config --unset-all log.excludeDecoration &&
-	git config log.excludeDecoration refs/remotes/remote1/ &&
-	git maintenance run --task=prefetch &&
-
-	git config --get-all log.excludeDecoration >out &&
-	grep refs/remotes/remote1/ out &&
-	grep refs/prefetch/ out &&
-
-	git log --oneline --decorate --all >log &&
-	! grep "prefetch" log &&
-	! grep "remote1" log &&
-	grep "remote2" log &&
-
-	# a second run does not change the config
-	git maintenance run --task=prefetch &&
-	git log --oneline --decorate --all >log2 &&
-	test_cmp log log2
-'
-
 test_expect_success 'loose-objects task' '
 	# Repack everything so we know the state of the object dir
 	git repack -adk &&
diff --git a/t/t8001-annotate.sh b/t/t8001-annotate.sh
index a536a62..d7167f5 100755
--- a/t/t8001-annotate.sh
+++ b/t/t8001-annotate.sh
@@ -4,6 +4,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 PROG='git annotate'
diff --git a/t/t8002-blame.sh b/t/t8002-blame.sh
index ee4fdd8..0147de3 100755
--- a/t/t8002-blame.sh
+++ b/t/t8002-blame.sh
@@ -4,6 +4,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 PROG='git blame -c'
diff --git a/t/t8007-cat-file-textconv.sh b/t/t8007-cat-file-textconv.sh
index b067983..c8266f1 100755
--- a/t/t8007-cat-file-textconv.sh
+++ b/t/t8007-cat-file-textconv.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='git cat-file textconv support'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 cat >helper <<'EOF'
diff --git a/t/t8010-cat-file-filters.sh b/t/t8010-cat-file-filters.sh
index 31de4b6..ca04242 100755
--- a/t/t8010-cat-file-filters.sh
+++ b/t/t8010-cat-file-filters.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='git cat-file filters support'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup ' '
diff --git a/t/t8012-blame-colors.sh b/t/t8012-blame-colors.sh
index 90c75db..c3a5f6d 100755
--- a/t/t8012-blame-colors.sh
+++ b/t/t8012-blame-colors.sh
@@ -4,6 +4,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_CREATE_REPO_NO_TEMPLATE=1
 . ./test-lib.sh
 
 PROG='git blame -c'
diff --git a/t/t9100-git-svn-basic.sh b/t/t9100-git-svn-basic.sh
index 7c5b847..fea41b3 100755
--- a/t/t9100-git-svn-basic.sh
+++ b/t/t9100-git-svn-basic.sh
@@ -8,7 +8,6 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
-TEST_FAILS_SANITIZE_LEAK=true
 . ./lib-git-svn.sh
 
 prepare_utf8_locale
diff --git a/t/t9101-git-svn-props.sh b/t/t9101-git-svn-props.sh
index d043e80..52046e6 100755
--- a/t/t9101-git-svn-props.sh
+++ b/t/t9101-git-svn-props.sh
@@ -5,7 +5,6 @@
 
 test_description='git svn property tests'
 
-TEST_FAILS_SANITIZE_LEAK=true
 . ./lib-git-svn.sh
 
 mkdir import
diff --git a/t/t9104-git-svn-follow-parent.sh b/t/t9104-git-svn-follow-parent.sh
index 5cf2ef4..85d7358 100755
--- a/t/t9104-git-svn-follow-parent.sh
+++ b/t/t9104-git-svn-follow-parent.sh
@@ -5,7 +5,6 @@
 
 test_description='git svn fetching'
 
-TEST_FAILS_SANITIZE_LEAK=true
 . ./lib-git-svn.sh
 
 test_expect_success 'initialize repo' '
diff --git a/t/t9122-git-svn-author.sh b/t/t9122-git-svn-author.sh
index 527ba3d..0fc289a 100755
--- a/t/t9122-git-svn-author.sh
+++ b/t/t9122-git-svn-author.sh
@@ -2,7 +2,6 @@
 
 test_description='git svn authorship'
 
-TEST_FAILS_SANITIZE_LEAK=true
 . ./lib-git-svn.sh
 
 test_expect_success 'setup svn repository' '
diff --git a/t/t9132-git-svn-broken-symlink.sh b/t/t9132-git-svn-broken-symlink.sh
index 4d8d058..aeceffa 100755
--- a/t/t9132-git-svn-broken-symlink.sh
+++ b/t/t9132-git-svn-broken-symlink.sh
@@ -2,7 +2,6 @@
 
 test_description='test that git handles an svn repository with empty symlinks'
 
-TEST_FAILS_SANITIZE_LEAK=true
 . ./lib-git-svn.sh
 test_expect_success 'load svn dumpfile' '
 	svnadmin load "$rawsvnrepo" <<EOF
diff --git a/t/t9162-git-svn-dcommit-interactive.sh b/t/t9162-git-svn-dcommit-interactive.sh
index e2aa8ed..b3ce033 100755
--- a/t/t9162-git-svn-dcommit-interactive.sh
+++ b/t/t9162-git-svn-dcommit-interactive.sh
@@ -4,7 +4,6 @@
 
 test_description='git svn dcommit --interactive series'
 
-TEST_FAILS_SANITIZE_LEAK=true
 . ./lib-git-svn.sh
 
 test_expect_success 'initialize repo' '
diff --git a/t/t9301-fast-import-notes.sh b/t/t9301-fast-import-notes.sh
index 1ae4d7c..5841322 100755
--- a/t/t9301-fast-import-notes.sh
+++ b/t/t9301-fast-import-notes.sh
@@ -7,6 +7,7 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 
diff --git a/t/t9700-perl-git.sh b/t/t9700-perl-git.sh
index 102c133..4aa5d90 100755
--- a/t/t9700-perl-git.sh
+++ b/t/t9700-perl-git.sh
@@ -4,17 +4,12 @@
 #
 
 test_description='perl interface (Git.pm)'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-perl.sh
 
-if ! test_have_prereq PERL; then
-	skip_all='skipping perl interface tests, perl not available'
-	test_done
-fi
-
-perl -MTest::More -e 0 2>/dev/null || {
-	skip_all="Perl Test::More unavailable, skipping test"
-	test_done
-}
+skip_all_if_no_Test_More
 
 # set up test repository
 
@@ -50,11 +45,9 @@
      git config --add test.pathmulti bar
      '
 
-# The external test will outputs its own plan
-test_external_has_tap=1
-
-test_external_without_stderr \
-    'Perl API' \
-    perl "$TEST_DIRECTORY"/t9700/test.pl
+test_expect_success 'use t9700/test.pl to test Git.pm' '
+	"$PERL_PATH" "$TEST_DIRECTORY"/t9700/test.pl 2>stderr &&
+	test_must_be_empty stderr
+'
 
 test_done
diff --git a/t/t9901-git-web--browse.sh b/t/t9901-git-web--browse.sh
index de7152f..19f56e5 100755
--- a/t/t9901-git-web--browse.sh
+++ b/t/t9901-git-web--browse.sh
@@ -5,6 +5,7 @@
 
 This test checks that git web--browse can handle various valid URLs.'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_web_browse () {
diff --git a/t/t9903-bash-prompt.sh b/t/t9903-bash-prompt.sh
index 6a30f57..d459fae 100755
--- a/t/t9903-bash-prompt.sh
+++ b/t/t9903-bash-prompt.sh
@@ -759,4 +759,20 @@
 	test_cmp expected "$actual"
 '
 
+test_expect_success 'prompt - conflict indicator' '
+	printf " (main|CONFLICT)" >expected &&
+	echo "stash" >file &&
+	git stash &&
+	test_when_finished "git stash drop" &&
+	echo "commit" >file &&
+	git commit -m "commit" file &&
+	test_when_finished "git reset --hard HEAD~" &&
+	test_must_fail git stash apply &&
+	(
+		GIT_PS1_SHOWCONFLICTSTATE="yes" &&
+		__git_ps1 >"$actual"
+	) &&
+	test_cmp expected "$actual"
+'
+
 test_done
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 8c44856..c6479f2 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -633,7 +633,7 @@
 # - Explicitly using test_have_prereq.
 #
 # - Implicitly by specifying the prerequisite tag in the calls to
-#   test_expect_{success,failure} and test_external{,_without_stderr}.
+#   test_expect_{success,failure}
 #
 # The single parameter is the prerequisite tag (a simple word, in all
 # capital letters by convention).
@@ -835,93 +835,6 @@
 	test_finish_
 }
 
-# test_external runs external test scripts that provide continuous
-# test output about their progress, and succeeds/fails on
-# zero/non-zero exit code.  It outputs the test output on stdout even
-# in non-verbose mode, and announces the external script with "# run
-# <n>: ..." before running it.  When providing relative paths, keep in
-# mind that all scripts run in "trash directory".
-# Usage: test_external description command arguments...
-# Example: test_external 'Perl API' perl ../path/to/test.pl
-test_external () {
-	test "$#" = 4 && { test_prereq=$1; shift; } || test_prereq=
-	test "$#" = 3 ||
-	BUG "not 3 or 4 parameters to test_external"
-	descr="$1"
-	shift
-	test_verify_prereq
-	export test_prereq
-	if ! test_skip "$descr" "$@"
-	then
-		# Announce the script to reduce confusion about the
-		# test output that follows.
-		say_color "" "# run $test_count: $descr ($*)"
-		# Export TEST_DIRECTORY, TRASH_DIRECTORY and GIT_TEST_LONG
-		# to be able to use them in script
-		export TEST_DIRECTORY TRASH_DIRECTORY GIT_TEST_LONG
-		# Run command; redirect its stderr to &4 as in
-		# test_run_, but keep its stdout on our stdout even in
-		# non-verbose mode.
-		"$@" 2>&4
-		if test "$?" = 0
-		then
-			if test $test_external_has_tap -eq 0; then
-				test_ok_ "$descr"
-			else
-				say_color "" "# test_external test $descr was ok"
-				test_success=$(($test_success + 1))
-			fi
-		else
-			if test $test_external_has_tap -eq 0; then
-				test_failure_ "$descr" "$@"
-			else
-				say_color error "# test_external test $descr failed: $@"
-				test_failure=$(($test_failure + 1))
-			fi
-		fi
-	fi
-}
-
-# Like test_external, but in addition tests that the command generated
-# no output on stderr.
-test_external_without_stderr () {
-	# The temporary file has no (and must have no) security
-	# implications.
-	tmp=${TMPDIR:-/tmp}
-	stderr="$tmp/git-external-stderr.$$.tmp"
-	test_external "$@" 4> "$stderr"
-	test -f "$stderr" || error "Internal error: $stderr disappeared."
-	descr="no stderr: $1"
-	shift
-	say >&3 "# expecting no stderr from previous command"
-	if test ! -s "$stderr"
-	then
-		rm "$stderr"
-
-		if test $test_external_has_tap -eq 0; then
-			test_ok_ "$descr"
-		else
-			say_color "" "# test_external_without_stderr test $descr was ok"
-			test_success=$(($test_success + 1))
-		fi
-	else
-		if test "$verbose" = t
-		then
-			output=$(echo; echo "# Stderr is:"; cat "$stderr")
-		else
-			output=
-		fi
-		# rm first in case test_failure exits.
-		rm "$stderr"
-		if test $test_external_has_tap -eq 0; then
-			test_failure_ "$descr" "$@" "$output"
-		else
-			say_color error "# test_external_without_stderr test $descr failed: $@: $output"
-			test_failure=$(($test_failure + 1))
-		fi
-	fi
-}
-
 # debugging-friendly alternatives to "test [-f|-d|-e]"
 # The commands test the existence or non-existence of $1
 test_path_is_file () {
diff --git a/t/test-lib.sh b/t/test-lib.sh
index 120f118..377cc1c 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -238,6 +238,9 @@
 			;;
 		esac
 		;;
+	--invert-exit-code)
+		invert_exit_code=t
+		;;
 	*)
 		echo "error: unknown test option '$opt'" >&2; exit 1 ;;
 	esac
@@ -302,6 +305,11 @@
 TEST_NUMBER="${TEST_NUMBER#t}"
 TEST_RESULTS_DIR="$TEST_OUTPUT_DIRECTORY/test-results"
 TEST_RESULTS_BASE="$TEST_RESULTS_DIR/$TEST_NAME$TEST_STRESS_JOB_SFX"
+TEST_RESULTS_SAN_FILE_PFX=trace
+TEST_RESULTS_SAN_DIR_SFX=leak
+TEST_RESULTS_SAN_FILE=
+TEST_RESULTS_SAN_DIR="$TEST_RESULTS_DIR/$TEST_NAME.$TEST_RESULTS_SAN_DIR_SFX"
+TEST_RESULTS_SAN_DIR_NR_LEAKS_STARTUP=
 TRASH_DIRECTORY="trash directory.$TEST_NAME$TEST_STRESS_JOB_SFX"
 test -n "$root" && TRASH_DIRECTORY="$root/$TRASH_DIRECTORY"
 case "$TRASH_DIRECTORY" in
@@ -309,6 +317,16 @@
  *) TRASH_DIRECTORY="$TEST_OUTPUT_DIRECTORY/$TRASH_DIRECTORY" ;;
 esac
 
+# Utility functions using $TEST_RESULTS_* variables
+nr_san_dir_leaks_ () {
+	# stderr piped to /dev/null because the directory may have
+	# been "rmdir"'d already.
+	find "$TEST_RESULTS_SAN_DIR" \
+		-type f \
+		-name "$TEST_RESULTS_SAN_FILE_PFX.*" 2>/dev/null |
+	wc -l
+}
+
 # If --stress was passed, run this test repeatedly in several parallel loops.
 if test "$GIT_TEST_STRESS_STARTED" = "done"
 then
@@ -793,15 +811,31 @@
 	finalize_test_case_output ok "$@"
 }
 
+_invert_exit_code_failure_end_blurb () {
+	say_color warn "# faked up failures as TODO & now exiting with 0 due to --invert-exit-code"
+}
+
 test_failure_ () {
 	failure_label=$1
 	test_failure=$(($test_failure + 1))
-	say_color error "not ok $test_count - $1"
+	local pfx=""
+	if test -n "$invert_exit_code" # && test -n "$HARNESS_ACTIVE"
+	then
+		pfx="# TODO induced breakage (--invert-exit-code):"
+	fi
+	say_color error "not ok $test_count - ${pfx:+$pfx }$1"
 	shift
 	printf '%s\n' "$*" | sed -e 's/^/#	/'
 	if test -n "$immediate"
 	then
 		say_color error "1..$test_count"
+		if test -n "$invert_exit_code"
+		then
+			finalize_test_output
+			_invert_exit_code_failure_end_blurb
+			GIT_EXIT_OK=t
+			exit 0
+		fi
 		_error_exit
 	fi
 	finalize_test_case_output failure "$failure_label" "$@"
@@ -809,14 +843,14 @@
 
 test_known_broken_ok_ () {
 	test_fixed=$(($test_fixed+1))
-	say_color error "ok $test_count - $@ # TODO known breakage vanished"
-	finalize_test_case_output fixed "$@"
+	say_color error "ok $test_count - $1 # TODO known breakage vanished"
+	finalize_test_case_output fixed "$1"
 }
 
 test_known_broken_failure_ () {
 	test_broken=$(($test_broken+1))
-	say_color warn "not ok $test_count - $@ # TODO known breakage"
-	finalize_test_case_output broken "$@"
+	say_color warn "not ok $test_count - $1 # TODO known breakage"
+	finalize_test_case_output broken "$1"
 }
 
 test_debug () {
@@ -1173,9 +1207,67 @@
 	teardown_malloc_check
 }
 
-test_done () {
-	GIT_EXIT_OK=t
+sanitize_leak_log_message_ () {
+	local new="$1" &&
+	local old="$2" &&
+	local file="$3" &&
 
+	printf "With SANITIZE=leak at exit we have %d leak logs, but started with %d
+
+This means that we have a blindspot where git is leaking but we're
+losing the exit code somewhere, or not propagating it appropriately
+upwards!
+
+See the logs at \"%s.*\";
+those logs are reproduced below." \
+	       "$new" "$old" "$file"
+}
+
+check_test_results_san_file_ () {
+	if test -z "$TEST_RESULTS_SAN_FILE"
+	then
+		return
+	fi &&
+	local old="$TEST_RESULTS_SAN_DIR_NR_LEAKS_STARTUP" &&
+	local new="$(nr_san_dir_leaks_)" &&
+
+	if test $new -le $old
+	then
+		return
+	fi &&
+	local out="$(sanitize_leak_log_message_ "$new" "$old" "$TEST_RESULTS_SAN_FILE")" &&
+	say_color error "$out" &&
+	if test "$old" != 0
+	then
+		echo &&
+		say_color error "The logs include output from past runs to avoid" &&
+		say_color error "that remove 'test-results' between runs."
+	fi &&
+	say_color error "$(cat "$TEST_RESULTS_SAN_FILE".*)" &&
+
+	if test -n "$passes_sanitize_leak" && test "$test_failure" = 0
+	then
+		say "As TEST_PASSES_SANITIZE_LEAK=true and our logs show we're leaking, exit non-zero!" &&
+		invert_exit_code=t
+	elif test -n "$passes_sanitize_leak"
+	then
+		say "As TEST_PASSES_SANITIZE_LEAK=true and our logs show we're leaking, and we're failing for other reasons too..." &&
+		invert_exit_code=
+	elif test -n "$sanitize_leak_check" && test "$test_failure" = 0
+	then
+		say "As TEST_PASSES_SANITIZE_LEAK=true isn't set the above leak is 'ok' with GIT_TEST_PASSING_SANITIZE_LEAK=check" &&
+		invert_exit_code=
+	elif test -n "$sanitize_leak_check"
+	then
+		say "As TEST_PASSES_SANITIZE_LEAK=true isn't set the above leak is 'ok' with GIT_TEST_PASSING_SANITIZE_LEAK=check" &&
+		invert_exit_code=t
+	else
+		say "With GIT_TEST_SANITIZE_LEAK_LOG=true our logs revealed a memory leak, exit non-zero!" &&
+		invert_exit_code=t
+	fi
+}
+
+test_done () {
 	# Run the atexit commands _before_ the trash directory is
 	# removed, so the commands can access pidfiles and socket files.
 	test_atexit_handler
@@ -1215,28 +1307,32 @@
 	fi
 	case "$test_failure" in
 	0)
-		if test $test_external_has_tap -eq 0
+		if test $test_remaining -gt 0
 		then
-			if test $test_remaining -gt 0
-			then
-				say_color pass "# passed all $msg"
-			fi
-
-			# Maybe print SKIP message
-			test -z "$skip_all" || skip_all="# SKIP $skip_all"
-			case "$test_count" in
-			0)
-				say "1..$test_count${skip_all:+ $skip_all}"
-				;;
-			*)
-				test -z "$skip_all" ||
-				say_color warn "$skip_all"
-				say "1..$test_count"
-				;;
-			esac
+			say_color pass "# passed all $msg"
 		fi
 
-		if test -z "$debug" && test -n "$remove_trash"
+		# Maybe print SKIP message
+		test -z "$skip_all" || skip_all="# SKIP $skip_all"
+		case "$test_count" in
+		0)
+			say "1..$test_count${skip_all:+ $skip_all}"
+			;;
+		*)
+			test -z "$skip_all" ||
+			say_color warn "$skip_all"
+			say "1..$test_count"
+			;;
+		esac
+
+		if test -n "$stress" && test -n "$invert_exit_code"
+		then
+			# We're about to move our "$TRASH_DIRECTORY"
+			# to "$TRASH_DIRECTORY.stress-failed" if
+			# --stress is combined with
+			# --invert-exit-code.
+			say "with --stress and --invert-exit-code we're not removing '$TRASH_DIRECTORY'"
+		elif test -z "$debug" && test -n "$remove_trash"
 		then
 			test -d "$TRASH_DIRECTORY" ||
 			error "Tests passed but trash directory already removed before test cleanup; aborting"
@@ -1249,17 +1345,35 @@
 			} ||
 			error "Tests passed but test cleanup failed; aborting"
 		fi
+
+		check_test_results_san_file_ "$test_failure"
+
+		if test -z "$skip_all" && test -n "$invert_exit_code"
+		then
+			say_color warn "# faking up non-zero exit with --invert-exit-code"
+			GIT_EXIT_OK=t
+			exit 1
+		fi
+
 		test_at_end_hook_
 
+		GIT_EXIT_OK=t
 		exit 0 ;;
 
 	*)
-		if test $test_external_has_tap -eq 0
+		say_color error "# failed $test_failure among $msg"
+		say "1..$test_count"
+
+		check_test_results_san_file_ "$test_failure"
+
+		if test -n "$invert_exit_code"
 		then
-			say_color error "# failed $test_failure among $msg"
-			say "1..$test_count"
+			_invert_exit_code_failure_end_blurb
+			GIT_EXIT_OK=t
+			exit 0
 		fi
 
+		GIT_EXIT_OK=t
 		exit 1 ;;
 
 	esac
@@ -1392,14 +1506,12 @@
 GITPERLLIB="$GIT_BUILD_DIR"/perl/build/lib
 export GITPERLLIB
 test -d "$GIT_BUILD_DIR"/templates/blt || {
-	error "You haven't built things yet, have you?"
+	BAIL_OUT "You haven't built things yet, have you?"
 }
 
 if ! test -x "$GIT_BUILD_DIR"/t/helper/test-tool$X
 then
-	echo >&2 'You need to build test-tool:'
-	echo >&2 'Run "make t/helper/test-tool" in the source (toplevel) directory'
-	exit 1
+	BAIL_OUT 'You need to build test-tool; Run "make t/helper/test-tool" in the source (toplevel) directory'
 fi
 
 # Are we running this test at all?
@@ -1413,24 +1525,70 @@
 	test_done
 fi
 
-# skip non-whitelisted tests when compiled with SANITIZE=leak
+BAIL_OUT_ENV_NEEDS_SANITIZE_LEAK () {
+	BAIL_OUT "$1 has no effect except when compiled with SANITIZE=leak"
+}
+
 if test -n "$SANITIZE_LEAK"
 then
-	if test_bool_env GIT_TEST_PASSING_SANITIZE_LEAK false
-	then
-		# We need to see it in "git env--helper" (via
-		# test_bool_env)
-		export TEST_PASSES_SANITIZE_LEAK
+	# Normalize with test_bool_env
+	passes_sanitize_leak=
 
-		if ! test_bool_env TEST_PASSES_SANITIZE_LEAK false
-		then
-			skip_all="skipping $this_test under GIT_TEST_PASSING_SANITIZE_LEAK=true"
-			test_done
-		fi
+	# We need to see TEST_PASSES_SANITIZE_LEAK in "git
+	# env--helper" (via test_bool_env)
+	export TEST_PASSES_SANITIZE_LEAK
+	if test_bool_env TEST_PASSES_SANITIZE_LEAK false
+	then
+		passes_sanitize_leak=t
 	fi
-elif test_bool_env GIT_TEST_PASSING_SANITIZE_LEAK false
+
+	if test "$GIT_TEST_PASSING_SANITIZE_LEAK" = "check"
+	then
+		sanitize_leak_check=t
+		if test -n "$invert_exit_code"
+		then
+			BAIL_OUT "cannot use --invert-exit-code under GIT_TEST_PASSING_SANITIZE_LEAK=check"
+		fi
+
+		if test -z "$passes_sanitize_leak"
+		then
+			say "in GIT_TEST_PASSING_SANITIZE_LEAK=check mode, setting --invert-exit-code for TEST_PASSES_SANITIZE_LEAK != true"
+			invert_exit_code=t
+		fi
+	elif test -z "$passes_sanitize_leak" &&
+	     test_bool_env GIT_TEST_PASSING_SANITIZE_LEAK false
+	then
+		skip_all="skipping $this_test under GIT_TEST_PASSING_SANITIZE_LEAK=true"
+		test_done
+	fi
+
+	if test_bool_env GIT_TEST_SANITIZE_LEAK_LOG false
+	then
+		if ! mkdir -p "$TEST_RESULTS_SAN_DIR"
+		then
+			BAIL_OUT "cannot create $TEST_RESULTS_SAN_DIR"
+		fi &&
+		TEST_RESULTS_SAN_FILE="$TEST_RESULTS_SAN_DIR/$TEST_RESULTS_SAN_FILE_PFX"
+
+		# In case "test-results" is left over from a previous
+		# run: Only report if new leaks show up.
+		TEST_RESULTS_SAN_DIR_NR_LEAKS_STARTUP=$(nr_san_dir_leaks_)
+
+		# Don't litter *.leak dirs if there was nothing to report
+		test_atexit "rmdir \"$TEST_RESULTS_SAN_DIR\" 2>/dev/null || :"
+
+		prepend_var LSAN_OPTIONS : dedup_token_length=9999
+		prepend_var LSAN_OPTIONS : log_exe_name=1
+		prepend_var LSAN_OPTIONS : log_path=\"$TEST_RESULTS_SAN_FILE\"
+		export LSAN_OPTIONS
+	fi
+elif test "$GIT_TEST_PASSING_SANITIZE_LEAK" = "check" ||
+     test_bool_env GIT_TEST_PASSING_SANITIZE_LEAK false
 then
-	BAIL_OUT "GIT_TEST_PASSING_SANITIZE_LEAK=true has no effect except when compiled with SANITIZE=leak"
+	BAIL_OUT_ENV_NEEDS_SANITIZE_LEAK "GIT_TEST_PASSING_SANITIZE_LEAK=true"
+elif test_bool_env GIT_TEST_SANITIZE_LEAK_LOG false
+then
+	BAIL_OUT_ENV_NEEDS_SANITIZE_LEAK "GIT_TEST_SANITIZE_LEAK_LOG=true"
 fi
 
 # Last-minute variable setup
@@ -1453,15 +1611,15 @@
 
 # Test repository
 remove_trash_directory "$TRASH_DIRECTORY" || {
-	GIT_EXIT_OK=t
-	echo >&5 "FATAL: Cannot prepare test area"
-	exit 1
+	BAIL_OUT 'cannot prepare test area'
 }
 
 remove_trash=t
 if test -z "$TEST_NO_CREATE_REPO"
 then
-	git init "$TRASH_DIRECTORY" >&3 2>&4 ||
+	git init \
+	    ${TEST_CREATE_REPO_NO_TEMPLATE:+--template=} \
+	    "$TRASH_DIRECTORY" >&3 2>&4 ||
 	error "cannot run git init"
 else
 	mkdir -p "$TRASH_DIRECTORY"
@@ -1469,7 +1627,7 @@
 
 # Use -P to resolve symlinks in our working directory so that the cwd
 # in subprocesses like git equals our $PWD (for pathname comparisons).
-cd -P "$TRASH_DIRECTORY" || exit 1
+cd -P "$TRASH_DIRECTORY" || BAIL_OUT "cannot cd -P to \"$TRASH_DIRECTORY\""
 
 start_test_output "$0"
 
diff --git a/tempfile.c b/tempfile.c
index 2024c82..e27048f 100644
--- a/tempfile.c
+++ b/tempfile.c
@@ -14,16 +14,14 @@
  *
  * The possible states of a `tempfile` object are as follows:
  *
- * - Uninitialized. In this state the object's `on_list` field must be
- *   zero but the rest of its contents need not be initialized. As
- *   soon as the object is used in any way, it is irrevocably
- *   registered in `tempfile_list`, and `on_list` is set.
+ * - Inactive/unallocated. The only way to get a tempfile is via a creation
+ *   function like create_tempfile(). Once allocated, the tempfile is on the
+ *   global tempfile_list and considered active.
  *
  * - Active, file open (after `create_tempfile()` or
  *   `reopen_tempfile()`). In this state:
  *
  *   - the temporary file exists
- *   - `active` is set
  *   - `filename` holds the filename of the temporary file
  *   - `fd` holds a file descriptor open for writing to it
  *   - `fp` holds a pointer to an open `FILE` object if and only if
@@ -35,14 +33,8 @@
  *   `fd` is -1, and `fp` is `NULL`.
  *
  * - Inactive (after `delete_tempfile()`, `rename_tempfile()`, or a
- *   failed attempt to create a temporary file). In this state:
- *
- *   - `active` is unset
- *   - `filename` is empty (usually, though there are transitory
- *     states in which this condition doesn't hold). Client code should
- *     *not* rely on the filename being empty in this state.
- *   - `fd` is -1 and `fp` is `NULL`
- *   - the object is removed from `tempfile_list` (but could be used again)
+ *   failed attempt to create a temporary file). The struct is removed from
+ *   the global tempfile_list and deallocated.
  *
  * A temporary file is owned by the process that created it. The
  * `tempfile` has an `owner` field that records the owner's PID. This
@@ -59,14 +51,11 @@
 static void remove_template_directory(struct tempfile *tempfile,
 				      int in_signal_handler)
 {
-	if (tempfile->directorylen > 0 &&
-	    tempfile->directorylen < tempfile->filename.len &&
-	    tempfile->filename.buf[tempfile->directorylen] == '/') {
-		strbuf_setlen(&tempfile->filename, tempfile->directorylen);
+	if (tempfile->directory) {
 		if (in_signal_handler)
-			rmdir(tempfile->filename.buf);
+			rmdir(tempfile->directory);
 		else
-			rmdir_or_warn(tempfile->filename.buf);
+			rmdir_or_warn(tempfile->directory);
 	}
 }
 
@@ -89,8 +78,6 @@
 		else
 			unlink_or_warn(p->filename.buf);
 		remove_template_directory(p, in_signal_handler);
-
-		p->active = 0;
 	}
 }
 
@@ -111,11 +98,10 @@
 	struct tempfile *tempfile = xmalloc(sizeof(*tempfile));
 	tempfile->fd = -1;
 	tempfile->fp = NULL;
-	tempfile->active = 0;
 	tempfile->owner = 0;
 	INIT_LIST_HEAD(&tempfile->list);
 	strbuf_init(&tempfile->filename, 0);
-	tempfile->directorylen = 0;
+	tempfile->directory = NULL;
 	return tempfile;
 }
 
@@ -123,9 +109,6 @@
 {
 	static int initialized;
 
-	if (is_tempfile_active(tempfile))
-		BUG("activate_tempfile called for active object");
-
 	if (!initialized) {
 		sigchain_push_common(remove_tempfiles_on_signal);
 		atexit(remove_tempfiles_on_exit);
@@ -134,14 +117,13 @@
 
 	volatile_list_add(&tempfile->list, &tempfile_list);
 	tempfile->owner = getpid();
-	tempfile->active = 1;
 }
 
 static void deactivate_tempfile(struct tempfile *tempfile)
 {
-	tempfile->active = 0;
-	strbuf_release(&tempfile->filename);
 	volatile_list_del(&tempfile->list);
+	strbuf_release(&tempfile->filename);
+	free(tempfile->directory);
 	free(tempfile);
 }
 
@@ -254,7 +236,7 @@
 
 	tempfile = new_tempfile();
 	strbuf_swap(&tempfile->filename, &sb);
-	tempfile->directorylen = directorylen;
+	tempfile->directory = xmemdupz(tempfile->filename.buf, directorylen);
 	tempfile->fd = fd;
 	activate_tempfile(tempfile);
 	return tempfile;
diff --git a/tempfile.h b/tempfile.h
index d7804a2..d0413af 100644
--- a/tempfile.h
+++ b/tempfile.h
@@ -77,12 +77,11 @@
 
 struct tempfile {
 	volatile struct volatile_list_head list;
-	volatile sig_atomic_t active;
 	volatile int fd;
 	FILE *volatile fp;
 	volatile pid_t owner;
 	struct strbuf filename;
-	size_t directorylen;
+	char *directory;
 };
 
 /*
@@ -221,7 +220,7 @@
 
 static inline int is_tempfile_active(struct tempfile *tempfile)
 {
-	return tempfile && tempfile->active;
+	return !!tempfile;
 }
 
 /*
diff --git a/trace2/tr2_tgt_event.c b/trace2/tr2_tgt_event.c
index c5c8cfb..37a3163 100644
--- a/trace2/tr2_tgt_event.c
+++ b/trace2/tr2_tgt_event.c
@@ -479,9 +479,12 @@
 {
 	const char *event_name = "def_param";
 	struct json_writer jw = JSON_WRITER_INIT;
+	enum config_scope scope = current_config_scope();
+	const char *scope_name = config_scope_name(scope);
 
 	jw_object_begin(&jw, 0);
 	event_fmt_prepare(event_name, file, line, NULL, &jw);
+	jw_object_string(&jw, "scope", scope_name);
 	jw_object_string(&jw, "param", param);
 	jw_object_string(&jw, "value", value);
 	jw_end(&jw);
diff --git a/trace2/tr2_tgt_normal.c b/trace2/tr2_tgt_normal.c
index c42fbad..69f8033 100644
--- a/trace2/tr2_tgt_normal.c
+++ b/trace2/tr2_tgt_normal.c
@@ -298,8 +298,11 @@
 			const char *value)
 {
 	struct strbuf buf_payload = STRBUF_INIT;
+	enum config_scope scope = current_config_scope();
+	const char *scope_name = config_scope_name(scope);
 
-	strbuf_addf(&buf_payload, "def_param %s=%s", param, value);
+	strbuf_addf(&buf_payload, "def_param scope:%s %s=%s", scope_name, param,
+		    value);
 	normal_io_write_fl(file, line, &buf_payload);
 	strbuf_release(&buf_payload);
 }
diff --git a/trace2/tr2_tgt_perf.c b/trace2/tr2_tgt_perf.c
index a1eff8b..8cb7924 100644
--- a/trace2/tr2_tgt_perf.c
+++ b/trace2/tr2_tgt_perf.c
@@ -441,12 +441,17 @@
 {
 	const char *event_name = "def_param";
 	struct strbuf buf_payload = STRBUF_INIT;
+	struct strbuf scope_payload = STRBUF_INIT;
+	enum config_scope scope = current_config_scope();
+	const char *scope_name = config_scope_name(scope);
 
 	strbuf_addf(&buf_payload, "%s:%s", param, value);
+	strbuf_addf(&scope_payload, "%s:%s", "scope", scope_name);
 
-	perf_io_write_fl(file, line, event_name, NULL, NULL, NULL, NULL,
-			 &buf_payload);
+	perf_io_write_fl(file, line, event_name, NULL, NULL, NULL,
+			 scope_payload.buf, &buf_payload);
 	strbuf_release(&buf_payload);
+	strbuf_release(&scope_payload);
 }
 
 static void fn_repo_fl(const char *file, int line,
diff --git a/trailer.c b/trailer.c
index d419c20..0fd5b14 100644
--- a/trailer.c
+++ b/trailer.c
@@ -478,7 +478,8 @@
 	{ "ifmissing", TRAILER_IF_MISSING }
 };
 
-static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
+static int git_trailer_default_config(const char *conf_key, const char *value,
+				      void *cb UNUSED)
 {
 	const char *trailer_item, *variable_name;
 
@@ -509,7 +510,8 @@
 	return 0;
 }
 
-static int git_trailer_config(const char *conf_key, const char *value, void *cb)
+static int git_trailer_config(const char *conf_key, const char *value,
+			      void *cb UNUSED)
 {
 	const char *trailer_item, *variable_name;
 	struct arg_item *item;
diff --git a/transport.c b/transport.c
index b51e991..1687ad7 100644
--- a/transport.c
+++ b/transport.c
@@ -142,7 +142,7 @@
 
 static struct ref *get_refs_from_bundle(struct transport *transport,
 					int for_push,
-					struct transport_ls_refs_options *transport_options)
+					struct transport_ls_refs_options *transport_options UNUSED)
 {
 	struct bundle_transport_data *data = transport->data;
 	struct ref *result = NULL;
@@ -386,7 +386,8 @@
 	args.cloning = transport->cloning;
 	args.update_shallow = data->options.update_shallow;
 	args.from_promisor = data->options.from_promisor;
-	args.filter_options = data->options.filter_options;
+	list_objects_filter_copy(&args.filter_options,
+				 &data->options.filter_options);
 	args.refetch = data->options.refetch;
 	args.stateless_rpc = transport->stateless_rpc;
 	args.server_options = transport->server_options;
@@ -453,6 +454,7 @@
 
 	free_refs(refs_tmp);
 	free_refs(refs);
+	list_objects_filter_release(&args.filter_options);
 	return ret;
 }
 
@@ -893,6 +895,7 @@
 		finish_connect(data->conn);
 	}
 
+	list_objects_filter_release(&data->options.filter_options);
 	free(data);
 	return 0;
 }
diff --git a/unpack-trees.c b/unpack-trees.c
index 90b9211..bae8121 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -1423,7 +1423,7 @@
  * from the tree walk at the given traverse_info.
  */
 static int is_sparse_directory_entry(struct cache_entry *ce,
-				     struct name_entry *name,
+				     const struct name_entry *name,
 				     struct traverse_info *info)
 {
 	if (!ce || !name || !S_ISSPARSEDIR(ce->ce_mode))
@@ -1562,7 +1562,7 @@
 			}
 		}
 
-		if (!is_sparse_directory_entry(src[0], names, info) &&
+		if (!is_sparse_directory_entry(src[0], p, info) &&
 		    !is_new_sparse_dir &&
 		    traverse_trees_recursive(n, dirmask, mask & ~dirmask,
 						    names, info) < 0) {
diff --git a/upload-pack.c b/upload-pack.c
index 3a851b3..abf2c11 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -455,6 +455,7 @@
 	return;
 
  fail:
+	free(output_state);
 	send_client_data(3, abort_msg, sizeof(abort_msg),
 			 pack_data->use_sideband);
 	die("git upload-pack: %s", abort_msg);
@@ -1169,7 +1170,7 @@
 }
 
 static int check_ref(const char *refname_full, const struct object_id *oid,
-		     int flag, void *cb_data)
+		     int flag UNUSED, void *cb_data UNUSED)
 {
 	const char *refname = strip_namespace(refname_full);
 
@@ -1193,7 +1194,7 @@
 }
 
 static int send_ref(const char *refname, const struct object_id *oid,
-		    int flag, void *cb_data)
+		    int flag UNUSED, void *cb_data)
 {
 	static const char *capabilities = "multi_ack thin-pack side-band"
 		" side-band-64k ofs-delta shallow deepen-since deepen-not"
@@ -1235,7 +1236,8 @@
 	return 0;
 }
 
-static int find_symref(const char *refname, const struct object_id *oid,
+static int find_symref(const char *refname,
+		       const struct object_id *oid UNUSED,
 		       int flag, void *cb_data)
 {
 	const char *symref_target;
@@ -1321,18 +1323,27 @@
 		data->advertise_sid = git_config_bool(var, value);
 	}
 
-	if (current_config_scope() != CONFIG_SCOPE_LOCAL &&
-	    current_config_scope() != CONFIG_SCOPE_WORKTREE) {
-		if (!strcmp("uploadpack.packobjectshook", var))
-			return git_config_string(&data->pack_objects_hook, var, value);
-	}
-
 	if (parse_object_filter_config(var, value, data) < 0)
 		return -1;
 
 	return parse_hide_refs_config(var, value, "uploadpack");
 }
 
+static int upload_pack_protected_config(const char *var, const char *value, void *cb_data)
+{
+	struct upload_pack_data *data = cb_data;
+
+	if (!strcmp("uploadpack.packobjectshook", var))
+		return git_config_string(&data->pack_objects_hook, var, value);
+	return 0;
+}
+
+static void get_upload_pack_config(struct upload_pack_data *data)
+{
+	git_config(upload_pack_config, data);
+	git_protected_config(upload_pack_protected_config, data);
+}
+
 void upload_pack(const int advertise_refs, const int stateless_rpc,
 		 const int timeout)
 {
@@ -1340,8 +1351,7 @@
 	struct upload_pack_data data;
 
 	upload_pack_data_init(&data);
-
-	git_config(upload_pack_config, &data);
+	get_upload_pack_config(&data);
 
 	data.stateless_rpc = stateless_rpc;
 	data.timeout = timeout;
@@ -1400,18 +1410,14 @@
 	const char *arg;
 	if (skip_prefix(line, "want ", &arg)) {
 		struct object_id oid;
-		struct commit *commit;
 		struct object *o;
 
 		if (get_oid_hex(arg, &oid))
 			die("git upload-pack: protocol error, "
 			    "expected to get oid, not '%s'", line);
 
-		commit = lookup_commit_in_graph(the_repository, &oid);
-		if (commit)
-			o = &commit->object;
-		else
-			o = parse_object(the_repository, &oid);
+		o = parse_object_with_flags(the_repository, &oid,
+					    PARSE_OBJECT_SKIP_HASH_CHECK);
 
 		if (!o) {
 			packet_writer_error(writer,
@@ -1695,8 +1701,7 @@
 
 	upload_pack_data_init(&data);
 	data.use_sideband = LARGE_PACKET_MAX;
-
-	git_config(upload_pack_config, &data);
+	get_upload_pack_config(&data);
 
 	while (state != FETCH_DONE) {
 		switch (state) {
diff --git a/walker.c b/walker.c
index c5e2921..99d0e0e 100644
--- a/walker.c
+++ b/walker.c
@@ -215,8 +215,10 @@
 	return -1;
 }
 
-static int mark_complete(const char *path, const struct object_id *oid,
-			 int flag, void *cb_data)
+static int mark_complete(const char *path UNUSED,
+			 const struct object_id *oid,
+			 int flag UNUSED,
+			 void *cb_data UNUSED)
 {
 	struct commit *commit = lookup_commit_reference_gently(the_repository,
 							       oid, 1);
diff --git a/wrapper.c b/wrapper.c
index 1c3c970..299d648 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -161,28 +161,6 @@
 		die_errno(_("could not setenv '%s'"), name ? name : "(null)");
 }
 
-/*
- * Limit size of IO chunks, because huge chunks only cause pain.  OS X
- * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
- * the absence of bugs, large chunks can result in bad latencies when
- * you decide to kill the process.
- *
- * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
- * that is smaller than that, clip it to SSIZE_MAX, as a call to
- * read(2) or write(2) larger than that is allowed to fail.  As the last
- * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
- * to override this, if the definition of SSIZE_MAX given by the platform
- * is broken.
- */
-#ifndef MAX_IO_SIZE
-# define MAX_IO_SIZE_DEFAULT (8*1024*1024)
-# if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
-#  define MAX_IO_SIZE SSIZE_MAX
-# else
-#  define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
-# endif
-#endif
-
 /**
  * xopen() is the same as open(), but it die()s if the open() fails.
  */
@@ -616,10 +594,16 @@
 	}
 }
 
+static void log_trace_fsync_if(const char *key, intmax_t value)
+{
+	if (value)
+		trace2_data_intmax("fsync", the_repository, key, value);
+}
+
 void trace_git_fsync_stats(void)
 {
-	trace2_data_intmax("fsync", the_repository, "fsync/writeout-only", count_fsync_writeout_only);
-	trace2_data_intmax("fsync", the_repository, "fsync/hardware-flush", count_fsync_hardware_flush);
+	log_trace_fsync_if("fsync/writeout-only", count_fsync_writeout_only);
+	log_trace_fsync_if("fsync/hardware-flush", count_fsync_hardware_flush);
 }
 
 static int warn_if_unremovable(const char *op, const char *file, int rc)
diff --git a/wt-status.c b/wt-status.c
index 867e3e4..5813174 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -947,9 +947,11 @@
 	wt_longstatus_print_trailer(s);
 }
 
-static int stash_count_refs(struct object_id *ooid, struct object_id *noid,
-			    const char *email, timestamp_t timestamp, int tz,
-			    const char *message, void *cb_data)
+static int stash_count_refs(struct object_id *ooid UNUSED,
+			    struct object_id *noid UNUSED,
+			    const char *email UNUSED,
+			    timestamp_t timestamp UNUSED, int tz UNUSED,
+			    const char *message UNUSED, void *cb_data)
 {
 	int *c = cb_data;
 	(*c)++;
@@ -1612,8 +1614,10 @@
 	struct object_id noid;
 };
 
-static int grab_1st_switch(struct object_id *ooid, struct object_id *noid,
-			   const char *email, timestamp_t timestamp, int tz,
+static int grab_1st_switch(struct object_id *ooid UNUSED,
+			   struct object_id *noid,
+			   const char *email UNUSED,
+			   timestamp_t timestamp UNUSED, int tz UNUSED,
 			   const char *message, void *cb_data)
 {
 	struct grab_1st_switch_cbdata *cb = cb_data;
diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h
index 72e25a9..bb56b23 100644
--- a/xdiff/xdiff.h
+++ b/xdiff/xdiff.h
@@ -120,6 +120,7 @@
 
 
 #define xdl_malloc(x) xmalloc(x)
+#define xdl_calloc(n, sz) xcalloc(n, sz)
 #define xdl_free(ptr) free(ptr)
 #define xdl_realloc(ptr,x) xrealloc(ptr,x)
 
diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
index 758410c..32652de 100644
--- a/xdiff/xdiffi.c
+++ b/xdiff/xdiffi.c
@@ -321,12 +321,12 @@
 		return -1;
 
 	if (XDF_DIFF_ALG(xpp->flags) == XDF_PATIENCE_DIFF) {
-		res = xdl_do_patience_diff(mf1, mf2, xpp, xe);
+		res = xdl_do_patience_diff(xpp, xe);
 		goto out;
 	}
 
 	if (XDF_DIFF_ALG(xpp->flags) == XDF_HISTOGRAM_DIFF) {
-		res = xdl_do_histogram_diff(mf1, mf2, xpp, xe);
+		res = xdl_do_histogram_diff(xpp, xe);
 		goto out;
 	}
 
@@ -337,7 +337,7 @@
 	 * One is to store the forward path and one to store the backward path.
 	 */
 	ndiags = xe->xdf1.nreff + xe->xdf2.nreff + 3;
-	if (!(kvd = (long *) xdl_malloc((2 * ndiags + 2) * sizeof(long)))) {
+	if (!XDL_ALLOC_ARRAY(kvd, 2 * ndiags + 2)) {
 
 		xdl_free_env(xe);
 		return -1;
diff --git a/xdiff/xdiffi.h b/xdiff/xdiffi.h
index 8f1c7c8..126c9d8 100644
--- a/xdiff/xdiffi.h
+++ b/xdiff/xdiffi.h
@@ -56,9 +56,7 @@
 void xdl_free_script(xdchange_t *xscr);
 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 		  xdemitconf_t const *xecfg);
-int xdl_do_patience_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
-		xdfenv_t *env);
-int xdl_do_histogram_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
-		xdfenv_t *env);
+int xdl_do_patience_diff(xpparam_t const *xpp, xdfenv_t *env);
+int xdl_do_histogram_diff(xpparam_t const *xpp, xdfenv_t *env);
 
 #endif /* #if !defined(XDIFFI_H) */
diff --git a/xdiff/xhistogram.c b/xdiff/xhistogram.c
index 01decff..16a8fe2 100644
--- a/xdiff/xhistogram.c
+++ b/xdiff/xhistogram.c
@@ -251,7 +251,7 @@
 		    int line1, int count1, int line2, int count2)
 {
 	int b_ptr;
-	int sz, ret = -1;
+	int ret = -1;
 	struct histindex index;
 
 	memset(&index, 0, sizeof(index));
@@ -265,23 +265,16 @@
 	index.rcha.head = NULL;
 
 	index.table_bits = xdl_hashbits(count1);
-	sz = index.records_size = 1 << index.table_bits;
-	sz *= sizeof(struct record *);
-	if (!(index.records = (struct record **) xdl_malloc(sz)))
+	index.records_size = 1 << index.table_bits;
+	if (!XDL_CALLOC_ARRAY(index.records, index.records_size))
 		goto cleanup;
-	memset(index.records, 0, sz);
 
-	sz = index.line_map_size = count1;
-	sz *= sizeof(struct record *);
-	if (!(index.line_map = (struct record **) xdl_malloc(sz)))
+	index.line_map_size = count1;
+	if (!XDL_CALLOC_ARRAY(index.line_map, index.line_map_size))
 		goto cleanup;
-	memset(index.line_map, 0, sz);
 
-	sz = index.line_map_size;
-	sz *= sizeof(unsigned int);
-	if (!(index.next_ptrs = (unsigned int *) xdl_malloc(sz)))
+	if (!XDL_CALLOC_ARRAY(index.next_ptrs, index.line_map_size))
 		goto cleanup;
-	memset(index.next_ptrs, 0, sz);
 
 	/* lines / 4 + 1 comes from xprepare.c:xdl_prepare_ctx() */
 	if (xdl_cha_init(&index.rcha, sizeof(struct record), count1 / 4 + 1) < 0)
@@ -369,8 +362,7 @@
 	return result;
 }
 
-int xdl_do_histogram_diff(mmfile_t *file1, mmfile_t *file2,
-	xpparam_t const *xpp, xdfenv_t *env)
+int xdl_do_histogram_diff(xpparam_t const *xpp, xdfenv_t *env)
 {
 	return histogram_diff(xpp, env,
 		env->xdf1.dstart + 1, env->xdf1.dend - env->xdf1.dstart + 1,
diff --git a/xdiff/xmacros.h b/xdiff/xmacros.h
index ae4636c..8487bb3 100644
--- a/xdiff/xmacros.h
+++ b/xdiff/xmacros.h
@@ -49,5 +49,23 @@
 		((unsigned long) __p[2]) << 16 | ((unsigned long) __p[3]) << 24; \
 } while (0)
 
+/* Allocate an array of nr elements, returns NULL on failure */
+#define XDL_ALLOC_ARRAY(p, nr)				\
+	((p) = SIZE_MAX / sizeof(*(p)) >= (size_t)(nr)	\
+		? xdl_malloc((nr) * sizeof(*(p)))	\
+		: NULL)
+
+/* Allocate an array of nr zeroed out elements, returns NULL on failure */
+#define XDL_CALLOC_ARRAY(p, nr)	((p) = xdl_calloc(nr, sizeof(*(p))))
+
+/*
+ * Ensure array p can accommodate at least nr elements, growing the
+ * array and updating alloc (which is the number of allocated
+ * elements) as necessary. Frees p and returns -1 on failure, returns
+ * 0 on success
+ */
+#define XDL_ALLOC_GROW(p, nr, alloc)	\
+	(-!((nr) <= (alloc) ||		\
+	    ((p) = xdl_alloc_grow_helper((p), (nr), &(alloc), sizeof(*(p))))))
 
 #endif /* #if !defined(XMACROS_H) */
diff --git a/xdiff/xpatience.c b/xdiff/xpatience.c
index 1a21c6a..a2d8955 100644
--- a/xdiff/xpatience.c
+++ b/xdiff/xpatience.c
@@ -69,7 +69,6 @@
 	} *entries, *first, *last;
 	/* were common records found? */
 	unsigned long has_matches;
-	mmfile_t *file1, *file2;
 	xdfenv_t *env;
 	xpparam_t const *xpp;
 };
@@ -139,23 +138,17 @@
  *
  * It is assumed that env has been prepared using xdl_prepare().
  */
-static int fill_hashmap(mmfile_t *file1, mmfile_t *file2,
-		xpparam_t const *xpp, xdfenv_t *env,
+static int fill_hashmap(xpparam_t const *xpp, xdfenv_t *env,
 		struct hashmap *result,
 		int line1, int count1, int line2, int count2)
 {
-	result->file1 = file1;
-	result->file2 = file2;
 	result->xpp = xpp;
 	result->env = env;
 
 	/* We know exactly how large we want the hash map */
 	result->alloc = count1 * 2;
-	result->entries = (struct entry *)
-		xdl_malloc(result->alloc * sizeof(struct entry));
-	if (!result->entries)
+	if (!XDL_CALLOC_ARRAY(result->entries, result->alloc))
 		return -1;
-	memset(result->entries, 0, result->alloc * sizeof(struct entry));
 
 	/* First, fill with entries from the first file */
 	while (count1--)
@@ -200,7 +193,7 @@
  */
 static int find_longest_common_sequence(struct hashmap *map, struct entry **res)
 {
-	struct entry **sequence = xdl_malloc(map->nr * sizeof(struct entry *));
+	struct entry **sequence;
 	int longest = 0, i;
 	struct entry *entry;
 
@@ -211,7 +204,7 @@
 	 */
 	int anchor_i = -1;
 
-	if (!sequence)
+	if (!XDL_ALLOC_ARRAY(sequence, map->nr))
 		return -1;
 
 	for (entry = map->first; entry; entry = entry->next) {
@@ -257,8 +250,7 @@
 	return record1->ha == record2->ha;
 }
 
-static int patience_diff(mmfile_t *file1, mmfile_t *file2,
-		xpparam_t const *xpp, xdfenv_t *env,
+static int patience_diff(xpparam_t const *xpp, xdfenv_t *env,
 		int line1, int count1, int line2, int count2);
 
 static int walk_common_sequence(struct hashmap *map, struct entry *first,
@@ -289,8 +281,7 @@
 
 		/* Recurse */
 		if (next1 > line1 || next2 > line2) {
-			if (patience_diff(map->file1, map->file2,
-					map->xpp, map->env,
+			if (patience_diff(map->xpp, map->env,
 					line1, next1 - line1,
 					line2, next2 - line2))
 				return -1;
@@ -329,8 +320,7 @@
  *
  * This function assumes that env was prepared with xdl_prepare_env().
  */
-static int patience_diff(mmfile_t *file1, mmfile_t *file2,
-		xpparam_t const *xpp, xdfenv_t *env,
+static int patience_diff(xpparam_t const *xpp, xdfenv_t *env,
 		int line1, int count1, int line2, int count2)
 {
 	struct hashmap map;
@@ -349,7 +339,7 @@
 	}
 
 	memset(&map, 0, sizeof(map));
-	if (fill_hashmap(file1, file2, xpp, env, &map,
+	if (fill_hashmap(xpp, env, &map,
 			line1, count1, line2, count2))
 		return -1;
 
@@ -377,9 +367,7 @@
 	return result;
 }
 
-int xdl_do_patience_diff(mmfile_t *file1, mmfile_t *file2,
-		xpparam_t const *xpp, xdfenv_t *env)
+int xdl_do_patience_diff(xpparam_t const *xpp, xdfenv_t *env)
 {
-	return patience_diff(file1, file2, xpp, env,
-			1, env->xdf1.nrec, 1, env->xdf2.nrec);
+	return patience_diff(xpp, env, 1, env->xdf1.nrec, 1, env->xdf2.nrec);
 }
diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
index 1057527..c84549f 100644
--- a/xdiff/xprepare.c
+++ b/xdiff/xprepare.c
@@ -78,15 +78,14 @@
 
 		return -1;
 	}
-	if (!(cf->rchash = (xdlclass_t **) xdl_malloc(cf->hsize * sizeof(xdlclass_t *)))) {
+	if (!XDL_CALLOC_ARRAY(cf->rchash, cf->hsize)) {
 
 		xdl_cha_free(&cf->ncha);
 		return -1;
 	}
-	memset(cf->rchash, 0, cf->hsize * sizeof(xdlclass_t *));
 
 	cf->alloc = size;
-	if (!(cf->rcrecs = (xdlclass_t **) xdl_malloc(cf->alloc * sizeof(xdlclass_t *)))) {
+	if (!XDL_ALLOC_ARRAY(cf->rcrecs, cf->alloc)) {
 
 		xdl_free(cf->rchash);
 		xdl_cha_free(&cf->ncha);
@@ -112,7 +111,6 @@
 	long hi;
 	char const *line;
 	xdlclass_t *rcrec;
-	xdlclass_t **rcrecs;
 
 	line = rec->ptr;
 	hi = (long) XDL_HASHLONG(rec->ha, cf->hbits);
@@ -128,14 +126,8 @@
 			return -1;
 		}
 		rcrec->idx = cf->count++;
-		if (cf->count > cf->alloc) {
-			cf->alloc *= 2;
-			if (!(rcrecs = (xdlclass_t **) xdl_realloc(cf->rcrecs, cf->alloc * sizeof(xdlclass_t *)))) {
-
+		if (XDL_ALLOC_GROW(cf->rcrecs, cf->count, cf->alloc))
 				return -1;
-			}
-			cf->rcrecs = rcrecs;
-		}
 		cf->rcrecs[rcrec->idx] = rcrec;
 		rcrec->line = line;
 		rcrec->size = rec->size;
@@ -164,7 +156,7 @@
 	unsigned long hav;
 	char const *blk, *cur, *top, *prev;
 	xrecord_t *crec;
-	xrecord_t **recs, **rrecs;
+	xrecord_t **recs;
 	xrecord_t **rhash;
 	unsigned long *ha;
 	char *rchg;
@@ -178,26 +170,21 @@
 
 	if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0)
 		goto abort;
-	if (!(recs = (xrecord_t **) xdl_malloc(narec * sizeof(xrecord_t *))))
+	if (!XDL_ALLOC_ARRAY(recs, narec))
 		goto abort;
 
 	hbits = xdl_hashbits((unsigned int) narec);
 	hsize = 1 << hbits;
-	if (!(rhash = (xrecord_t **) xdl_malloc(hsize * sizeof(xrecord_t *))))
+	if (!XDL_CALLOC_ARRAY(rhash, hsize))
 		goto abort;
-	memset(rhash, 0, hsize * sizeof(xrecord_t *));
 
 	nrec = 0;
 	if ((cur = blk = xdl_mmfile_first(mf, &bsize))) {
 		for (top = blk + bsize; cur < top; ) {
 			prev = cur;
 			hav = xdl_hash_record(&cur, top, xpp->flags);
-			if (nrec >= narec) {
-				narec *= 2;
-				if (!(rrecs = (xrecord_t **) xdl_realloc(recs, narec * sizeof(xrecord_t *))))
-					goto abort;
-				recs = rrecs;
-			}
+			if (XDL_ALLOC_GROW(recs, nrec + 1, narec))
+				goto abort;
 			if (!(crec = xdl_cha_alloc(&xdf->rcha)))
 				goto abort;
 			crec->ptr = prev;
@@ -209,15 +196,14 @@
 		}
 	}
 
-	if (!(rchg = (char *) xdl_malloc((nrec + 2) * sizeof(char))))
+	if (!XDL_CALLOC_ARRAY(rchg, nrec + 2))
 		goto abort;
-	memset(rchg, 0, (nrec + 2) * sizeof(char));
 
 	if ((XDF_DIFF_ALG(xpp->flags) != XDF_PATIENCE_DIFF) &&
 	    (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF)) {
-		if (!(rindex = xdl_malloc((nrec + 1) * sizeof(*rindex))))
+		if (!XDL_ALLOC_ARRAY(rindex, nrec + 1))
 			goto abort;
-		if (!(ha = xdl_malloc((nrec + 1) * sizeof(*ha))))
+		if (!XDL_ALLOC_ARRAY(ha, nrec + 1))
 			goto abort;
 	}
 
@@ -383,11 +369,8 @@
 	xdlclass_t *rcrec;
 	char *dis, *dis1, *dis2;
 
-	if (!(dis = (char *) xdl_malloc(xdf1->nrec + xdf2->nrec + 2))) {
-
+	if (!XDL_CALLOC_ARRAY(dis, xdf1->nrec + xdf2->nrec + 2))
 		return -1;
-	}
-	memset(dis, 0, xdf1->nrec + xdf2->nrec + 2);
 	dis1 = dis;
 	dis2 = dis1 + xdf1->nrec + 1;
 
diff --git a/xdiff/xutils.c b/xdiff/xutils.c
index 115b2b1..9e36f24 100644
--- a/xdiff/xutils.c
+++ b/xdiff/xutils.c
@@ -432,3 +432,20 @@
 
 	return 0;
 }
+
+void* xdl_alloc_grow_helper(void *p, long nr, long *alloc, size_t size)
+{
+	void *tmp = NULL;
+	size_t n = ((LONG_MAX - 16) / 2 >= *alloc) ? 2 * *alloc + 16 : LONG_MAX;
+	if (nr > n)
+		n = nr;
+	if (SIZE_MAX / size >= n)
+		tmp = xdl_realloc(p, n * size);
+	if (tmp) {
+		*alloc = n;
+	} else {
+		xdl_free(p);
+		*alloc = 0;
+	}
+	return tmp;
+}
diff --git a/xdiff/xutils.h b/xdiff/xutils.h
index fba7bae..fd0bba9 100644
--- a/xdiff/xutils.h
+++ b/xdiff/xutils.h
@@ -42,6 +42,7 @@
 int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
 		       int line1, int count1, int line2, int count2);
 
-
+/* Do not call this function, use XDL_ALLOC_GROW instead */
+void* xdl_alloc_grow_helper(void* p, long nr, long* alloc, size_t size);
 
 #endif /* #if !defined(XUTILS_H) */