diff --git a/.github/workflows/l10n.yml b/.github/workflows/l10n.yml
new file mode 100644
index 0000000..27f72f0
--- /dev/null
+++ b/.github/workflows/l10n.yml
@@ -0,0 +1,105 @@
+name: git-l10n
+
+on: [push, pull_request_target]
+
+jobs:
+  git-po-helper:
+    if: >-
+      endsWith(github.repository, '/git-po') ||
+      contains(github.head_ref, 'l10n') ||
+      contains(github.ref, 'l10n')
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+    steps:
+      - name: Setup base and head objects
+        id: setup-tips
+        run: |
+          if test "${{ github.event_name }}" = "pull_request_target"
+          then
+            base=${{ github.event.pull_request.base.sha }}
+            head=${{ github.event.pull_request.head.sha }}
+          else
+            base=${{ github.event.before }}
+            head=${{ github.event.after }}
+          fi
+          echo "::set-output name=base::$base"
+          echo "::set-output name=head::$head"
+      - name: Run partial clone
+        run: |
+          git -c init.defaultBranch=master init --bare .
+          git remote add \
+            --mirror=fetch \
+            origin \
+            https://github.com/${{ github.repository }}
+          # Fetch tips that may be unreachable from github.ref:
+          # - For a forced push, "$base" may be unreachable.
+          # - For a "pull_request_target" event, "$head" may be unreachable.
+          args=
+          for commit in \
+            ${{ steps.setup-tips.outputs.base }} \
+            ${{ steps.setup-tips.outputs.head }}
+          do
+            case $commit in
+            *[^0]*)
+              args="$args $commit"
+              ;;
+            *)
+              # Should not fetch ZERO-OID.
+              ;;
+            esac
+          done
+          git -c protocol.version=2 fetch \
+            --progress \
+            --no-tags \
+            --no-write-fetch-head \
+            --filter=blob:none \
+            origin \
+            ${{ github.ref }} \
+            $args
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '>=1.16'
+      - name: Install git-po-helper
+        run: go install github.com/git-l10n/git-po-helper@main
+      - name: Install other dependencies
+        run: |
+          sudo apt-get update -q &&
+          sudo apt-get install -q -y gettext
+      - name: Run git-po-helper
+        id: check-commits
+        run: |
+          exit_code=0
+          git-po-helper check-commits \
+            --github-action-event="${{ github.event_name }}" -- \
+            ${{ steps.setup-tips.outputs.base }}..${{ steps.setup-tips.outputs.head }} \
+            >git-po-helper.out 2>&1 || exit_code=$?
+          if test $exit_code -ne 0 || grep -q WARNING git-po-helper.out
+          then
+            # Remove ANSI colors which are proper for console logs but not
+            # proper for PR comment.
+            echo "COMMENT_BODY<<EOF" >>$GITHUB_ENV
+            perl -pe 's/\e\[[0-9;]*m//g; s/\bEOF$//g' git-po-helper.out >>$GITHUB_ENV
+            echo "EOF" >>$GITHUB_ENV
+          fi
+          cat git-po-helper.out
+          exit $exit_code
+      - name: Create comment in pull request for report
+        uses: mshick/add-pr-comment@v1
+        if: >-
+          always() &&
+          github.event_name == 'pull_request_target' &&
+          env.COMMENT_BODY != ''
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          repo-token-user-login: 'github-actions[bot]'
+          message: >
+            ${{ steps.check-commits.outcome == 'failure' && 'Errors and warnings' || 'Warnings' }}
+            found by [git-po-helper](https://github.com/git-l10n/git-po-helper#readme) in workflow
+            [#${{ github.run_number }}](${{ env.GITHUB_SERVER_URL }}/${{ github.repository }}/actions/runs/${{ github.run_id }}):
+
+            ```
+
+            ${{ env.COMMENT_BODY }}
+
+            ```
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index b053b01..6ed6a9e 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -88,7 +88,7 @@
       env:
         HOME: ${{runner.workspace}}
         NO_PERL: 1
-      run: ci/make-test-artifacts.sh artifacts
+      run: . /etc/profile && ci/make-test-artifacts.sh artifacts
     - name: zip up tracked files
       run: git archive -o artifacts/tracked.tar.gz HEAD
     - name: upload tracked files and build artifacts
@@ -115,7 +115,7 @@
     - uses: git-for-windows/setup-git-for-windows-sdk@v1
     - name: test
       shell: bash
-      run: ci/run-test-slice.sh ${{matrix.nr}} 10
+      run: . /etc/profile && ci/run-test-slice.sh ${{matrix.nr}} 10
     - name: ci/print-test-failures.sh
       if: failure()
       shell: bash
@@ -198,8 +198,7 @@
       shell: bash
       env:
         NO_SVN_TESTS: 1
-        GIT_TEST_SKIP_REBASE_P: 1
-      run: ci/run-test-slice.sh ${{matrix.nr}} 10
+      run: . /etc/profile && ci/run-test-slice.sh ${{matrix.nr}} 10
     - name: ci/print-test-failures.sh
       if: failure()
       shell: bash
@@ -232,6 +231,9 @@
           - jobname: linux-gcc-default
             cc: gcc
             pool: ubuntu-latest
+          - jobname: linux-leaks
+            cc: gcc
+            pool: ubuntu-latest
     env:
       CC: ${{matrix.vector.cc}}
       jobname: ${{matrix.vector.jobname}}
diff --git a/.gitignore b/.gitignore
index 311841f..054249b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -125,7 +125,6 @@
 /git-range-diff
 /git-read-tree
 /git-rebase
-/git-rebase--preserve-merges
 /git-receive-pack
 /git-reflog
 /git-remote
@@ -190,6 +189,7 @@
 /gitweb/static/gitweb.min.*
 /config-list.h
 /command-list.h
+/hook-list.h
 *.tar.gz
 *.dsc
 *.deb
@@ -224,6 +224,7 @@
 *.lib
 *.res
 *.sln
+*.sp
 *.suo
 *.ncb
 *.vcproj
diff --git a/Documentation/.gitignore b/Documentation/.gitignore
index 9022d48..1c3771e 100644
--- a/Documentation/.gitignore
+++ b/Documentation/.gitignore
@@ -14,4 +14,5 @@
 SubmittingPatches.txt
 tmp-doc-diff/
 GIT-ASCIIDOCFLAGS
+/.build/
 /GIT-EXCLUDED-PROGRAMS
diff --git a/Documentation/Makefile b/Documentation/Makefile
index f5605b7..ed656db 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -90,6 +90,7 @@
 TECH_DOCS += MyFirstContribution
 TECH_DOCS += MyFirstObjectWalk
 TECH_DOCS += SubmittingPatches
+TECH_DOCS += technical/bundle-format
 TECH_DOCS += technical/hash-function-transition
 TECH_DOCS += technical/http-protocol
 TECH_DOCS += technical/index-format
@@ -225,6 +226,7 @@
 
 ifneq ($(findstring $(MAKEFLAGS),s),s)
 ifndef V
+	QUIET		= @
 	QUIET_ASCIIDOC	= @echo '   ' ASCIIDOC $@;
 	QUIET_XMLTO	= @echo '   ' XMLTO $@;
 	QUIET_DB2TEXI	= @echo '   ' DB2TEXI $@;
@@ -232,11 +234,15 @@
 	QUIET_DBLATEX	= @echo '   ' DBLATEX $@;
 	QUIET_XSLTPROC	= @echo '   ' XSLTPROC $@;
 	QUIET_GEN	= @echo '   ' GEN $@;
-	QUIET_LINT	= @echo '   ' LINT $@;
 	QUIET_STDERR	= 2> /dev/null
 	QUIET_SUBDIR0	= +@subdir=
 	QUIET_SUBDIR1	= ;$(NO_SUBDIR) echo '   ' SUBDIR $$subdir; \
 			  $(MAKE) $(PRINT_DIR) -C $$subdir
+
+	QUIET_LINT_GITLINK	= @echo '   ' LINT GITLINK $<;
+	QUIET_LINT_MANSEC	= @echo '   ' LINT MAN SEC $<;
+	QUIET_LINT_MANEND	= @echo '   ' LINT MAN END $<;
+
 	export V
 endif
 endif
@@ -284,7 +290,7 @@
 ../GIT-VERSION-FILE: FORCE
 	$(QUIET_SUBDIR0)../ $(QUIET_SUBDIR1) GIT-VERSION-FILE
 
-ifneq ($(MAKECMDGOALS),clean)
+ifneq ($(filter-out lint-docs clean,$(MAKECMDGOALS)),)
 -include ../GIT-VERSION-FILE
 endif
 
@@ -343,6 +349,7 @@
             fi
 
 clean:
+	$(RM) -rf .build/
 	$(RM) *.xml *.xml+ *.html *.html+ *.1 *.5 *.7
 	$(RM) *.texi *.texi+ *.texi++ git.info gitman.info
 	$(RM) *.pdf
@@ -456,14 +463,61 @@
 print-man1:
 	@for i in $(MAN1_TXT); do echo $$i; done
 
-lint-docs::
-	$(QUIET_LINT)$(PERL_PATH) lint-gitlink.perl \
+## Lint: Common
+.build:
+	$(QUIET)mkdir $@
+.build/lint-docs: | .build
+	$(QUIET)mkdir $@
+
+## Lint: gitlink
+.build/lint-docs/gitlink: | .build/lint-docs
+	$(QUIET)mkdir $@
+.build/lint-docs/gitlink/howto: | .build/lint-docs/gitlink
+	$(QUIET)mkdir $@
+.build/lint-docs/gitlink/config: | .build/lint-docs/gitlink
+	$(QUIET)mkdir $@
+LINT_DOCS_GITLINK = $(patsubst %.txt,.build/lint-docs/gitlink/%.ok,$(HOWTO_TXT) $(DOC_DEP_TXT))
+$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink
+$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink/howto
+$(LINT_DOCS_GITLINK): | .build/lint-docs/gitlink/config
+$(LINT_DOCS_GITLINK): lint-gitlink.perl
+$(LINT_DOCS_GITLINK): .build/lint-docs/gitlink/%.ok: %.txt
+	$(QUIET_LINT_GITLINK)$(PERL_PATH) lint-gitlink.perl \
+		$< \
 		$(HOWTO_TXT) $(DOC_DEP_TXT) \
 		--section=1 $(MAN1_TXT) \
 		--section=5 $(MAN5_TXT) \
-		--section=7 $(MAN7_TXT); \
-	$(PERL_PATH) lint-man-end-blurb.perl $(MAN_TXT); \
-	$(PERL_PATH) lint-man-section-order.perl $(MAN_TXT);
+		--section=7 $(MAN7_TXT) >$@
+.PHONY: lint-docs-gitlink
+lint-docs-gitlink: $(LINT_DOCS_GITLINK)
+
+## Lint: man-end-blurb
+.build/lint-docs/man-end-blurb: | .build/lint-docs
+	$(QUIET)mkdir $@
+LINT_DOCS_MAN_END_BLURB = $(patsubst %.txt,.build/lint-docs/man-end-blurb/%.ok,$(MAN_TXT))
+$(LINT_DOCS_MAN_END_BLURB): | .build/lint-docs/man-end-blurb
+$(LINT_DOCS_MAN_END_BLURB): lint-man-end-blurb.perl
+$(LINT_DOCS_MAN_END_BLURB): .build/lint-docs/man-end-blurb/%.ok: %.txt
+	$(QUIET_LINT_MANEND)$(PERL_PATH) lint-man-end-blurb.perl $< >$@
+.PHONY: lint-docs-man-end-blurb
+lint-docs-man-end-blurb: $(LINT_DOCS_MAN_END_BLURB)
+
+## Lint: man-section-order
+.build/lint-docs/man-section-order: | .build/lint-docs
+	$(QUIET)mkdir $@
+LINT_DOCS_MAN_SECTION_ORDER = $(patsubst %.txt,.build/lint-docs/man-section-order/%.ok,$(MAN_TXT))
+$(LINT_DOCS_MAN_SECTION_ORDER): | .build/lint-docs/man-section-order
+$(LINT_DOCS_MAN_SECTION_ORDER): lint-man-section-order.perl
+$(LINT_DOCS_MAN_SECTION_ORDER): .build/lint-docs/man-section-order/%.ok: %.txt
+	$(QUIET_LINT_MANSEC)$(PERL_PATH) lint-man-section-order.perl $< >$@
+.PHONY: lint-docs-man-section-order
+lint-docs-man-section-order: $(LINT_DOCS_MAN_SECTION_ORDER)
+
+## Lint: list of targets above
+.PHONY: lint-docs
+lint-docs: lint-docs-gitlink
+lint-docs: lint-docs-man-end-blurb
+lint-docs: lint-docs-man-section-order
 
 ifeq ($(wildcard po/Makefile),po/Makefile)
 doc-l10n install-l10n::
diff --git a/Documentation/MyFirstContribution.txt b/Documentation/MyFirstContribution.txt
index 015cf24..b20bc8e 100644
--- a/Documentation/MyFirstContribution.txt
+++ b/Documentation/MyFirstContribution.txt
@@ -1029,22 +1029,42 @@
 [[v2-git-send-email]]
 === Sending v2
 
-Skip ahead to <<reviewing,Responding to Reviews>> for information on how to
-handle comments from reviewers. Continue this section when your topic branch is
-shaped the way you want it to look for your patchset v2.
+This section will focus on how to send a v2 of your patchset. To learn what
+should go into v2, skip ahead to <<reviewing,Responding to Reviews>> for
+information on how to handle comments from reviewers.
 
-When you're ready with the next iteration of your patch, the process is fairly
-similar.
-
-First, generate your v2 patches again:
+We'll reuse our `psuh` topic branch for v2. Before we make any changes, we'll
+mark the tip of our v1 branch for easy reference:
 
 ----
-$ git format-patch -v2 --cover-letter -o psuh/ master..psuh
+$ git checkout psuh
+$ git branch psuh-v1
 ----
 
-This will add your v2 patches, all named like `v2-000n-my-commit-subject.patch`,
-to the `psuh/` directory. You may notice that they are sitting alongside the v1
-patches; that's fine, but be careful when you are ready to send them.
+Refine your patch series by using `git rebase -i` to adjust commits based upon
+reviewer comments. Once the patch series is ready for submission, generate your
+patches again, but with some new flags:
+
+----
+$ git format-patch -v2 --cover-letter -o psuh/ --range-diff master..psuh-v1 master..
+----
+
+The `--range-diff master..psuh-v1` parameter tells `format-patch` to include a
+range-diff between `psuh-v1` and `psuh` in the cover letter (see
+linkgit:git-range-diff[1]). This helps tell reviewers about the differences
+between your v1 and v2 patches.
+
+The `-v2` parameter tells `format-patch` to output your patches
+as version "2". For instance, you may notice that your v2 patches are
+all named like `v2-000n-my-commit-subject.patch`. `-v2` will also format
+your patches by prefixing them with "[PATCH v2]" instead of "[PATCH]",
+and your range-diff will be prefaced with "Range-diff against v1".
+
+Afer you run this command, `format-patch` will output the patches to the `psuh/`
+directory, alongside the v1 patches. Using a single directory makes it easy to
+refer to the old v1 patches while proofreading the v2 patches, but you will need
+to be careful to send out only the v2 patches. We will use a pattern like
+"psuh/v2-*.patch" (not "psuh/*.patch", which would match v1 and v2 patches).
 
 Edit your cover letter again. Now is a good time to mention what's different
 between your last version and now, if it's something significant. You do not
@@ -1082,7 +1102,7 @@
 ----
 $ git send-email --to=target@example.com
 		 --in-reply-to="<foo.12345.author@example.com>"
-		 psuh/v2*
+		 psuh/v2-*.patch
 ----
 
 [[single-patch]]
diff --git a/Documentation/RelNotes/2.34.0.txt b/Documentation/RelNotes/2.34.0.txt
new file mode 100644
index 0000000..fdf7992
--- /dev/null
+++ b/Documentation/RelNotes/2.34.0.txt
@@ -0,0 +1,383 @@
+Git 2.34 Release Notes
+======================
+
+Updates since Git 2.33
+----------------------
+
+Backward compatibility notes
+
+ * The "--preserve-merges" option of "git rebase" has been removed.
+
+
+UI, Workflows & Features
+
+ * Pathname expansion (like "~username/") learned a way to specify a
+   location relative to Git installation (e.g. its $sharedir which is
+   $(prefix)/share), with "%(prefix)".
+
+ * Use `ort` instead of `recursive` as the default merge strategy.
+
+ * The userdiff pattern for "java" language has been updated.
+
+ * "git rebase" by default skips changes that are equivalent to
+   commits that are already in the history the branch is rebased onto;
+   give messages when this happens to let the users be aware of
+   skipped commits, and also teach them how to tell "rebase" to keep
+   duplicated changes.
+
+ * The advice message that "git cherry-pick" gives when it asks
+   conflicted replay of a commit to be resolved by the end user has
+   been updated.
+
+ * After "git clone --recurse-submodules", all submodules are cloned
+   but they are not by default recursed into by other commands.  With
+   submodule.stickyRecursiveClone configuration set, submodule.recurse
+   configuration is set to true in a repository created by "clone"
+   with "--recurse-submodules" option.
+
+ * The logic for auto-correction of misspelt subcommands learned to go
+   interactive when the help.autocorrect configuration variable is set
+   to 'prompt'.
+
+ * "git maintenance" scheduler learned to use systemd timers as a
+   possible backend.
+
+ * "git diff --submodule=diff" showed failure from run_command() when
+   trying to run diff inside a submodule, when the user manually
+   removes the submodule directory.
+
+ * "git bundle unbundle" learned to show progress display.
+
+ * In cone mode, the sparse-index code path learned to remove ignored
+   files (like build artifacts) outside the sparse cone, allowing the
+   entire directory outside the sparse cone to be removed, which is
+   especially useful when the sparse patterns change.
+
+ * Taking advantage of the CGI interface, http-backend has been
+   updated to enable protocol v2 automatically when the other side
+   asks for it.
+
+ * The credential-cache helper has been adjusted to Windows.
+
+ * The error in "git help no-such-git-command" is handled better.
+
+ * The unicode character width table (used for output alignment) has
+   been updated.
+
+ * The ref iteration code used to optionally allow dangling refs to be
+   shown, which has been tightened up.
+
+ * "git add", "git mv", and "git rm" have been adjusted to avoid
+   updating paths outside of the sparse-checkout definition unless
+   the user specifies a "--sparse" option.
+
+ * "git repack" has been taught to generate multi-pack reachability
+   bitmaps.
+
+ * "git fsck" has been taught to report mismatch between expected and
+   actual types of an object better.
+
+ * Use ssh public crypto for object and push-cert signing.
+
+
+Performance, Internal Implementation, Development Support etc.
+
+ * "git bisect" spawned "git show-branch" only to pretty-print the
+   title of the commit after checking out the next version to be
+   tested; this has been rewritten in C.
+
+ * "git add" can work better with the sparse index.
+
+ * Support for ancient versions of cURL library (pre 7.19.4) has been
+   dropped.
+
+ * A handful of tests that assumed implementation details of files
+   backend for refs have been cleaned up.
+
+ * trace2 logs learned to show parent process name to see in what
+   context Git was invoked.
+
+ * Loading of ref tips to prepare for common ancestry negotiation in
+   "git fetch-pack" has been optimized by taking advantage of the
+   commit graph when available.
+
+ * Remind developers that the userdiff patterns should be kept simple
+   and permissive, assuming that the contents they apply are always
+   syntactically correct.
+
+ * The current implementation of GIT_TEST_FAIL_PREREQS is broken in
+   that checking for the lack of a prerequisite would not work.  Avoid
+   the use of "if ! test_have_prereq X" in a test script.
+
+ * The revision traversal API has been optimized by taking advantage
+   of the commit-graph, when available, to determine if a commit is
+   reachable from any of the existing refs.
+
+ * "git fetch --quiet" optimization to avoid useless computation of
+   info that will never be displayed.
+
+ * Callers from older advice_config[] based API has been updated to
+   use the newer advice_if_enabled() and advice_enabled() API.
+
+ * Teach "test_pause" and "debug" helpers to allow using the HOME and
+   TERM environment variables the user usually uses.
+
+ * "make INSTALL_STRIP=-s install" allows the installation step to use
+   "install -s" to strip the binaries as they get installed.
+
+ * Code that handles large number of refs in the "git fetch" code
+   path has been optimized.
+
+ * The reachability bitmap file used to be generated only for a single
+   pack, but now we've learned to generate bitmaps for history that
+   span across multiple packfiles.
+
+ * The code to make "git grep" recurse into submodules has been
+   updated to migrate away from the "add submodule's object store as
+   an alternate object store" mechanism (which is suboptimal).
+
+ * The tracing of process ancestry information has been enhanced.
+
+ * Reduce number of write(2) system calls while sending the
+   ref advertisement.
+
+ * Update the build procedure to use the "-pedantic" build when
+   DEVELOPER makefile macro is in effect.
+
+ * Large part of "git submodule add" gets rewritten in C.
+
+ * The run-command API has been updated so that the callers can easily
+   ask the file descriptors open for packfiles to be closed immediately
+   before spawning commands that may trigger auto-gc.
+
+ * An oddball OPTION_ARGUMENT feature has been removed from the
+   parse-options API.
+
+ * The mergesort implementation used to sort linked list has been
+   optimized.
+
+ * Remove external declaration of functions that no longer exist.
+
+ * "git multi-pack-index write --bitmap" learns to propagate the
+   hashcache from original bitmap to resulting bitmap.
+
+ * CI learns to run the leak sanitizer builds.
+
+ * "git grep --recurse-submodules" takes trees and blobs from the
+   submodule repository, but the textconv settings when processing a
+   blob from the submodule is not taken from the submodule repository.
+   A test is added to demonstrate the issue, without fixing it.
+
+ * Teach "git help -c" into helping the command line completion of
+   configuration variables.
+
+ * When "git cmd -h" shows more than one line of usage text (e.g.
+   the cmd subcommand may take sub-sub-command), parse-options API
+   learned to align these lines, even across i18n/l10n.
+
+ * Prevent "make sparse" from running for the source files that
+   haven't been modified.
+
+ * The codepath to write a new version of .midx multi-pack index files
+   has learned to release the mmaped memory holding the current
+   version of .midx before removing them from the disk, as some
+   platforms do not allow removal of a file that still has mapping.
+
+
+Fixes since v2.33
+-----------------
+
+ * Input validation of "git pack-objects --stdin-packs" has been
+   corrected.
+
+ * Bugfix for common ancestor negotiation recently introduced in "git
+   push" code path.
+
+ * "git pull" had various corner cases that were not well thought out
+   around its --rebase backend, e.g. "git pull --ff-only" did not stop
+   but went ahead and rebased when the history on other side is not a
+   descendant of our history.  The series tries to fix them up.
+
+ * "git apply" miscounted the bytes and failed to read to the end of
+   binary hunks.
+
+ * "git range-diff" code clean-up.
+
+ * "git commit --fixup" now works with "--edit" again, after it was
+   broken in v2.32.
+
+ * Use upload-artifacts v1 (instead of v2) for 32-bit linux, as the
+   new version has a blocker bug for that architecture.
+
+ * Checking out all the paths from HEAD during the last conflicted
+   step in "git rebase" and continuing would cause the step to be
+   skipped (which is expected), but leaves MERGE_MSG file behind in
+   $GIT_DIR and confuses the next "git commit", which has been
+   corrected.
+
+ * Various bugs in "git rebase -r" have been fixed.
+
+ * mmap() imitation used to call xmalloc() that dies upon malloc()
+   failure, which has been corrected to just return an error to the
+   caller to be handled.
+
+ * "git diff --relative" segfaulted and/or produced incorrect result
+   when there are unmerged paths.
+
+ * The delayed checkout code path in "git checkout" etc. were chatty
+   even when --quiet and/or --no-progress options were given.
+
+ * "git branch -D <branch>" used to refuse to remove a broken branch
+   ref that points at a missing commit, which has been corrected.
+
+ * Build update for Apple clang.
+
+ * The parser for the "--nl" option of "git column" has been
+   corrected.
+
+ * "git upload-pack" which runs on the other side of "git fetch"
+   forgot to take the ref namespaces into account when handling
+   want-ref requests.
+
+ * The sparse-index support can corrupt the index structure by storing
+   a stale and/or uninitialized data, which has been corrected.
+
+ * Buggy tests could damage repositories outside the throw-away test
+   area we created.  We now by default export GIT_CEILING_DIRECTORIES
+   to limit the damage from such a stray test.
+
+ * Even when running "git send-email" without its own threaded
+   discussion support, a threading related header in one message is
+   carried over to the subsequent message to result in an unwanted
+   threading, which has been corrected.
+
+ * The output from "git fast-export", when its anonymization feature
+   is in use, showed an annotated tag incorrectly.
+
+ * Doc update plus improved error reporting.
+
+ * Recent "diff -m" changes broke "gitk", which has been corrected.
+
+ * Regression fix.
+
+ * The "git apply -3" code path learned not to bother the lower level
+   merge machinery when the three-way merge can be trivially resolved
+   without the content level merge.  This fixes a regression caused by
+   recent "-3way first and fall back to direct application" change.
+
+ * The code that optionally creates the *.rev reverse index file has
+   been optimized to avoid needless computation when it is not writing
+   the file out.
+
+ * "git range-diff -I... <range> <range>" segfaulted, which has been
+   corrected.
+
+ * The order in which various files that make up a single (conceptual)
+   packfile has been reevaluated and straightened up.  This matters in
+   correctness, as an incomplete set of files must not be shown to a
+   running Git.
+
+ * The "mode" word is useless in a call to open(2) that does not
+   create a new file.  Such a call in the files backend of the ref
+   subsystem has been cleaned up.
+
+ * "git update-ref --stdin" failed to flush its output as needed,
+   which potentially led the conversation to a deadlock.
+
+ * When "git am --abort" fails to abort correctly, it still exited
+   with exit status of 0, which has been corrected.
+
+ * Correct nr and alloc members of strvec struct to be of type size_t.
+
+ * "git stash", where the tentative change involves changing a
+   directory to a file (or vice versa), was confused, which has been
+   corrected.
+
+ * "git clone" from a repository whose HEAD is unborn into a bare
+   repository didn't follow the branch name the other side used, which
+   is corrected.
+
+ * "git cvsserver" had a long-standing bug in its authentication code,
+   which has finally been corrected (it is unclear and is a separate
+   question if anybody is seriously using it, though).
+
+ * "git difftool --dir-diff" mishandled symbolic links.
+
+ * Sensitive data in the HTTP trace were supposed to be redacted, but
+   we failed to do so in HTTP/2 requests.
+
+ * "make clean" has been updated to remove leftover .depend/
+   directories, even when it is not told to use them to compute header
+   dependencies.
+
+ * Protocol v0 clients can get stuck parsing a malformed feature line.
+
+ * A few kinds of changes "git status" can show were not documented.
+   (merge d2a534c515 ja/doc-status-types-and-copies later to maint).
+
+ * The mergesort implementation used to sort linked list has been
+   optimized.
+   (merge c90cfc225b rs/mergesort later to maint).
+
+ * An editor session launched during a Git operation (e.g. during 'git
+   commit') can leave the terminal in a funny state.  The code path
+   has updated to save the terminal state before, and restore it
+   after, it spawns an editor.
+   (merge 3d411afabc cm/save-restore-terminal later to maint).
+
+ * "git cat-file --batch" with the "--batch-all-objects" option is
+   supposed to iterate over all the objects found in a repository, but
+   it used to translate these object names using the replace mechanism,
+   which defeats the point of enumerating all objects in the repository.
+   This has been corrected.
+   (merge bf972896d7 jk/cat-file-batch-all-wo-replace later to maint).
+
+ * Recent sparse-index work broke safety against attempts to add paths
+   with trailing slashes to the index, which has been corrected.
+   (merge c8ad9d04c6 rs/make-verify-path-really-verify-again later to maint).
+
+ * The "--color-lines" and "--color-by-age" options of "git blame"
+   have been missing, which are now documented.
+   (merge 8c32856133 bs/doc-blame-color-lines later to maint).
+
+ * The PATH used in CI job may be too wide and let incompatible dlls
+   to be grabbed, which can cause the build&test to fail.  Tighten it.
+   (merge 7491ef6198 js/windows-ci-path-fix later to maint).
+
+ * Avoid performance measurements from getting ruined by gc and other
+   housekeeping pauses interfering in the middle.
+   (merge be79131a53 rs/disable-gc-during-perf-tests later to maint).
+
+ * Stop "git add --dry-run" from creating new blob and tree objects.
+   (merge e578d0311d rs/add-dry-run-without-objects later to maint).
+
+ * "git commit" gave duplicated error message when the object store
+   was unwritable, which has been corrected.
+   (merge 4ef91a2d79 ab/fix-commit-error-message-upon-unwritable-object-store later to maint).
+
+ * Recent sparse-index addition, namely any use of index_name_pos(),
+   can expand sparse index entries and breaks any code that walks
+   cache-tree or existing index entries.  One such instance of such a
+   breakage has been corrected.
+
+ * The xxdiff difftool backend can exit with status 128, which the
+   difftool-helper that launches the backend takes as a significant
+   failure, when it is not significant at all.  Work it around.
+   (merge 571f4348dd da/mergetools-special-case-xxdiff-exit-128 later to maint).
+
+ * Improve test framework around unwritable directories.
+   (merge 5d22e18965 ab/test-cleanly-recreate-trash-directory later to maint).
+
+ * Other code cleanup, docfix, build fix, etc.
+   (merge f188160be9 ab/bundle-remove-verbose-option later to maint).
+   (merge 8c6b4332b4 rs/close-pack-leakfix later to maint).
+   (merge 51b04c05b7 bs/difftool-msg-tweak later to maint).
+   (merge dd20e4a6db ab/make-compdb-fix later to maint).
+   (merge 6ffb990dc4 os/status-docfix later to maint).
+   (merge 100c2da2d3 rs/p3400-lose-tac later to maint).
+   (merge 76f3b69896 tb/aggregate-ignore-leading-whitespaces later to maint).
+   (merge 6e4fd8bfcd tz/doc-link-to-bundle-format-fix later to maint).
+   (merge f6c013dfa1 jc/doc-commit-header-continuation-line later to maint).
+   (merge ec9a37d69b ab/pkt-line-cleanup later to maint).
+   (merge 8650c6298c ab/fix-make-lint-docs later to maint).
+   (merge 1c720357ce ab/test-lib-diff-cleanup later to maint).
diff --git a/Documentation/blame-options.txt b/Documentation/blame-options.txt
index 117f4cf..9a66353 100644
--- a/Documentation/blame-options.txt
+++ b/Documentation/blame-options.txt
@@ -136,5 +136,16 @@
 	option.  An empty file name, `""`, will clear the list of revs from
 	previously processed files.
 
+--color-lines::
+	Color line annotations in the default format differently if they come from
+	the same commit as the preceding line. This makes it easier to distinguish
+	code blocks introduced by different commits. The color defaults to cyan and
+	can be adjusted using the `color.blame.repeatedLines` config option.
+
+--color-by-age::
+	Color line annotations depending on the age of the line in the default format.
+	The `color.blame.highlightRecent` config option controls what color is used for
+	each range of age.
+
 -h::
 	Show help message.
diff --git a/Documentation/config.txt b/Documentation/config.txt
index bf82766..1167e88 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -298,6 +298,15 @@
 	tilde expansion happens to such a string: `~/`
 	is expanded to the value of `$HOME`, and `~user/` to the
 	specified user's home directory.
++
+If a path starts with `%(prefix)/`, the remainder is interpreted as a
+path relative to Git's "runtime prefix", i.e. relative to the location
+where Git itself was installed. For example, `%(prefix)/bin/` refers to
+the directory in which the Git executable itself lives. If Git was
+compiled without runtime prefix support, the compiled-in prefix will be
+substituted instead. In the unlikely event that a literal path needs to
+be specified that should _not_ be expanded, it needs to be prefixed by
+`./`, like so: `./%(prefix)/bin`.
 
 
 Variables
diff --git a/Documentation/config/advice.txt b/Documentation/config/advice.txt
index 8b2849f..063eec2 100644
--- a/Documentation/config/advice.txt
+++ b/Documentation/config/advice.txt
@@ -44,6 +44,9 @@
 		Shown when linkgit:git-push[1] rejects a forced update of
 		a branch when its remote-tracking ref has updates that we
 		do not have locally.
+	skippedCherryPicks::
+		Shown when linkgit:git-rebase[1] skips a commit that has already
+		been cherry-picked onto the upstream branch.
 	statusAheadBehind::
 		Shown when linkgit:git-status[1] computes the ahead/behind
 		counts for a local ref compared to its remote tracking ref,
diff --git a/Documentation/config/branch.txt b/Documentation/config/branch.txt
index cc5f324..d323d73 100644
--- a/Documentation/config/branch.txt
+++ b/Documentation/config/branch.txt
@@ -85,10 +85,6 @@
 so that the local merge commits are included in the rebase (see
 linkgit:git-rebase[1] for details).
 +
-When `preserve` (or just 'p', deprecated in favor of `merges`), also pass
-`--preserve-merges` along to 'git rebase' so that locally committed merge
-commits will not be flattened by running 'git pull'.
-+
 When the value is `interactive` (or just 'i'), the rebase is run in interactive
 mode.
 +
diff --git a/Documentation/config/color.txt b/Documentation/config/color.txt
index e05d520..6e817f6 100644
--- a/Documentation/config/color.txt
+++ b/Documentation/config/color.txt
@@ -9,26 +9,27 @@
 	Use customized color for hints.
 
 color.blame.highlightRecent::
-	This can be used to color the metadata of a blame line depending
-	on age of the line.
+	Specify the line annotation color for `git blame --color-by-age`
+	depending upon the age of the line.
 +
-This setting should be set to a comma-separated list of color and date settings,
-starting and ending with a color, the dates should be set from oldest to newest.
-The metadata will be colored given the colors if the line was introduced
-before the given timestamp, overwriting older timestamped colors.
+This setting should be set to a comma-separated list of color and
+date settings, starting and ending with a color, the dates should be
+set from oldest to newest. The metadata will be colored with the
+specified colors if the line was introduced before the given
+timestamp, overwriting older timestamped colors.
 +
-Instead of an absolute timestamp relative timestamps work as well, e.g.
-2.weeks.ago is valid to address anything older than 2 weeks.
+Instead of an absolute timestamp relative timestamps work as well,
+e.g. `2.weeks.ago` is valid to address anything older than 2 weeks.
 +
-It defaults to 'blue,12 month ago,white,1 month ago,red', which colors
-everything older than one year blue, recent changes between one month and
-one year old are kept white, and lines introduced within the last month are
-colored red.
+It defaults to `blue,12 month ago,white,1 month ago,red`, which
+colors everything older than one year blue, recent changes between
+one month and one year old are kept white, and lines introduced
+within the last month are colored red.
 
 color.blame.repeatedLines::
-	Use the customized color for the part of git-blame output that
-	is repeated meta information per line (such as commit id,
-	author name, date and timezone). Defaults to cyan.
+	Use the specified color to colorize line annotations for
+	`git blame --color-lines`, if they come from the same commit as the
+	preceding line. Defaults to cyan.
 
 color.branch::
 	A boolean to enable/disable color in the output of
diff --git a/Documentation/config/gpg.txt b/Documentation/config/gpg.txt
index d94025c..4f30c7d 100644
--- a/Documentation/config/gpg.txt
+++ b/Documentation/config/gpg.txt
@@ -11,13 +11,13 @@
 
 gpg.format::
 	Specifies which key format to use when signing with `--gpg-sign`.
-	Default is "openpgp" and another possible value is "x509".
+	Default is "openpgp". Other possible values are "x509", "ssh".
 
 gpg.<format>.program::
 	Use this to customize the program used for the signing format you
 	chose. (see `gpg.program` and `gpg.format`) `gpg.program` can still
 	be used as a legacy synonym for `gpg.openpgp.program`. The default
-	value for `gpg.x509.program` is "gpgsm".
+	value for `gpg.x509.program` is "gpgsm" and `gpg.ssh.program` is "ssh-keygen".
 
 gpg.minTrustLevel::
 	Specifies a minimum trust level for signature verification.  If
@@ -33,3 +33,42 @@
 * `marginal`
 * `fully`
 * `ultimate`
+
+gpg.ssh.defaultKeyCommand:
+	This command that will be run when user.signingkey is not set and a ssh
+	signature is requested. On successful exit a valid ssh public key is
+	expected in the	first line of its output. To automatically use the first
+	available key from your ssh-agent set this to "ssh-add -L".
+
+gpg.ssh.allowedSignersFile::
+	A file containing ssh public keys which you are willing to trust.
+	The file consists of one or more lines of principals followed by an ssh
+	public key.
+	e.g.: user1@example.com,user2@example.com ssh-rsa AAAAX1...
+	See ssh-keygen(1) "ALLOWED SIGNERS" for details.
+	The principal is only used to identify the key and is available when
+	verifying a signature.
++
+SSH has no concept of trust levels like gpg does. To be able to differentiate
+between valid signatures and trusted signatures the trust level of a signature
+verification is set to `fully` when the public key is present in the allowedSignersFile.
+Otherwise the trust level is `undefined` and git verify-commit/tag will fail.
++
+This file can be set to a location outside of the repository and every developer
+maintains their own trust store. A central repository server could generate this
+file automatically from ssh keys with push access to verify the code against.
+In a corporate setting this file is probably generated at a global location
+from automation that already handles developer ssh keys.
++
+A repository that only allows signed commits can store the file
+in the repository itself using a path relative to the top-level of the working tree.
+This way only committers with an already valid key can add or change keys in the keyring.
++
+Using a SSH CA key with the cert-authority option
+(see ssh-keygen(1) "CERTIFICATES") is also valid.
+
+gpg.ssh.revocationFile::
+	Either a SSH KRL or a list of revoked public keys (without the principal prefix).
+	See ssh-keygen(1) for details.
+	If a public key is found in this file then it will always be treated
+	as having trust level "never" and signatures will show as invalid.
diff --git a/Documentation/config/help.txt b/Documentation/config/help.txt
index 783a90a..610701f 100644
--- a/Documentation/config/help.txt
+++ b/Documentation/config/help.txt
@@ -9,13 +9,15 @@
 
 help.autoCorrect::
 	If git detects typos and can identify exactly one valid command similar
-	to the error, git will automatically run the intended command after
-	waiting a duration of time defined by this configuration value in
-	deciseconds (0.1 sec).  If this value is 0, the suggested corrections
-	will be shown, but not executed. If it is a negative integer, or
-	"immediate", the suggested command
-	is run immediately. If "never", suggestions are not shown at all. The
-	default value is zero.
+	to the error, git will try to suggest the correct command or even
+	run the suggestion automatically. Possible config values are:
+	 - 0 (default): show the suggested command.
+	 - positive number: run the suggested command after specified
+deciseconds (0.1 sec).
+	 - "immediate": run the suggested command immediately.
+	 - "prompt": show the suggestion and prompt for confirmation to run
+the command.
+	 - "never": don't run or show any suggested command.
 
 help.htmlPath::
 	Specify the path where the HTML documentation resides. File system paths
diff --git a/Documentation/config/pack.txt b/Documentation/config/pack.txt
index 763f7af..ad7f73a 100644
--- a/Documentation/config/pack.txt
+++ b/Documentation/config/pack.txt
@@ -159,6 +159,10 @@
 	between an older, bitmapped pack and objects that have been
 	pushed since the last gc). The downside is that it consumes 4
 	bytes per object of disk space. Defaults to true.
++
+When writing a multi-pack reachability bitmap, no new namehashes are
+computed; instead, any namehashes stored in an existing bitmap are
+permuted into their appropriate location when writing a new bitmap.
 
 pack.writeReverseIndex::
 	When true, git will write a corresponding .rev file (see:
diff --git a/Documentation/config/pull.txt b/Documentation/config/pull.txt
index 5404830..9349e09 100644
--- a/Documentation/config/pull.txt
+++ b/Documentation/config/pull.txt
@@ -18,10 +18,6 @@
 so that the local merge commits are included in the rebase (see
 linkgit:git-rebase[1] for details).
 +
-When `preserve` (or just 'p', deprecated in favor of `merges`), also pass
-`--preserve-merges` along to 'git rebase' so that locally committed merge
-commits will not be flattened by running 'git pull'.
-+
 When the value is `interactive` (or just 'i'), the rebase is run in interactive
 mode.
 +
diff --git a/Documentation/config/user.txt b/Documentation/config/user.txt
index 59aec7c..ad78dce 100644
--- a/Documentation/config/user.txt
+++ b/Documentation/config/user.txt
@@ -36,3 +36,10 @@
 	commit, you can override the default selection with this variable.
 	This option is passed unchanged to gpg's --local-user parameter,
 	so you may specify a key using any method that gpg supports.
+	If gpg.format is set to "ssh" this can contain the literal ssh public
+	key (e.g.: "ssh-rsa XXXXXX identifier") or a file which contains it and
+	corresponds to the private key used for signing. The private key
+	needs to be available via ssh-agent. Alternatively it can be set to
+	a file containing a private key directly. If not set git will call
+	gpg.ssh.defaultKeyCommand (e.g.: "ssh-add -L") and try to use the first
+	key available.
diff --git a/Documentation/diff-format.txt b/Documentation/diff-format.txt
index fbbd410..7a9c3b6 100644
--- a/Documentation/diff-format.txt
+++ b/Documentation/diff-format.txt
@@ -59,7 +59,7 @@
 - D: deletion of a file
 - M: modification of the contents or mode of a file
 - R: renaming of a file
-- T: change in the type of the file
+- T: change in the type of the file (regular file, symbolic link or submodule)
 - U: file is unmerged (you must complete the merge before it can
   be committed)
 - X: "unknown" change type (most probably a bug, please report it)
diff --git a/Documentation/git-add.txt b/Documentation/git-add.txt
index be5e3ac..11eb70f 100644
--- a/Documentation/git-add.txt
+++ b/Documentation/git-add.txt
@@ -9,7 +9,7 @@
 --------
 [verse]
 'git add' [--verbose | -v] [--dry-run | -n] [--force | -f] [--interactive | -i] [--patch | -p]
-	  [--edit | -e] [--[no-]all | --[no-]ignore-removal | [--update | -u]]
+	  [--edit | -e] [--[no-]all | --[no-]ignore-removal | [--update | -u]] [--sparse]
 	  [--intent-to-add | -N] [--refresh] [--ignore-errors] [--ignore-missing] [--renormalize]
 	  [--chmod=(+|-)x] [--pathspec-from-file=<file> [--pathspec-file-nul]]
 	  [--] [<pathspec>...]
@@ -79,6 +79,13 @@
 --force::
 	Allow adding otherwise ignored files.
 
+--sparse::
+	Allow updating index entries outside of the sparse-checkout cone.
+	Normally, `git add` refuses to update index entries whose paths do
+	not fit within the sparse-checkout cone, since those files might
+	be removed from the working tree without warning. See
+	linkgit:git-sparse-checkout[1] for more details.
+
 -i::
 --interactive::
 	Add modified contents in the working tree interactively to
diff --git a/Documentation/git-archive.txt b/Documentation/git-archive.txt
index 9f81728..bc4e76a 100644
--- a/Documentation/git-archive.txt
+++ b/Documentation/git-archive.txt
@@ -93,12 +93,19 @@
 
 zip
 ~~~
--0::
-	Store the files instead of deflating them.
--9::
-	Highest and slowest compression level.  You can specify any
-	number from 1 to 9 to adjust compression speed and ratio.
+-<digit>::
+	Specify compression level.  Larger values allow the command
+	to spend more time to compress to smaller size.  Supported
+	values are from `-0` (store-only) to `-9` (best ratio).
+	Default is `-6` if not given.
 
+tar
+~~~
+-<number>::
+	Specify compression level. The value will be passed to the
+	compression command configured in `tar.<format>.command`. See
+	manual page of the configured command for the list of supported
+	levels and the default level if this option isn't specified.
 
 CONFIGURATION
 -------------
diff --git a/Documentation/git-blame.txt b/Documentation/git-blame.txt
index 3bf5d5d..d7a46cc 100644
--- a/Documentation/git-blame.txt
+++ b/Documentation/git-blame.txt
@@ -11,8 +11,8 @@
 'git blame' [-c] [-b] [-l] [--root] [-t] [-f] [-n] [-s] [-e] [-p] [-w] [--incremental]
 	    [-L <range>] [-S <revs-file>] [-M] [-C] [-C] [-C] [--since=<date>]
 	    [--ignore-rev <rev>] [--ignore-revs-file <file>]
-	    [--progress] [--abbrev=<n>] [<rev> | --contents <file> | --reverse <rev>..<rev>]
-	    [--] <file>
+	    [--color-lines] [--color-by-age] [--progress] [--abbrev=<n>]
+	    [<rev> | --contents <file> | --reverse <rev>..<rev>] [--] <file>
 
 DESCRIPTION
 -----------
@@ -93,6 +93,19 @@
 	is used for a caret to mark the boundary commit.
 
 
+THE DEFAULT FORMAT
+------------------
+
+When neither `--porcelain` nor `--incremental` option is specified,
+`git blame` will output annotation for each line with:
+
+- abbreviated object name for the commit the line came from;
+- author ident (by default author name and date, unless `-s` or `-e`
+  is specified); and
+- line number
+
+before the line contents.
+
 THE PORCELAIN FORMAT
 --------------------
 
diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index 5449767..8af42ef 100644
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -125,14 +125,14 @@
 
 -m::
 --move::
-	Move/rename a branch and the corresponding reflog.
+	Move/rename a branch, together with its config and reflog.
 
 -M::
 	Shortcut for `--move --force`.
 
 -c::
 --copy::
-	Copy a branch and the corresponding reflog.
+	Copy a branch, together with its config and reflog.
 
 -C::
 	Shortcut for `--copy --force`.
diff --git a/Documentation/git-bundle.txt b/Documentation/git-bundle.txt
index ac0d003..72ab813 100644
--- a/Documentation/git-bundle.txt
+++ b/Documentation/git-bundle.txt
@@ -13,7 +13,7 @@
 		    [--version=<version>] <file> <git-rev-list-args>
 'git bundle' verify [-q | --quiet] <file>
 'git bundle' list-heads <file> [<refname>...]
-'git bundle' unbundle <file> [<refname>...]
+'git bundle' unbundle [--progress] <file> [<refname>...]
 
 DESCRIPTION
 -----------
@@ -51,10 +51,10 @@
 unbundled using the `--fix-thin` option to linkgit:git-index-pack[1].
 
 There is no option to create a "thick pack" when using revision
-exclusions, users should not be concerned about the difference. By
-using "thin packs" bundles created using exclusions are smaller in
+exclusions, and users should not be concerned about the difference. By
+using "thin packs", bundles created using exclusions are smaller in
 size. That they're "thin" under the hood is merely noted here as a
-curiosity, and as a reference to other documentation
+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
@@ -144,7 +144,7 @@
 SPECIFYING REFERENCES
 ---------------------
 
-Revisions must accompanied by reference names to be packaged in a
+Revisions must be accompanied by reference names to be packaged in a
 bundle.
 
 More than one reference may be packaged, and more than one set of prerequisite objects can
diff --git a/Documentation/git-cat-file.txt b/Documentation/git-cat-file.txt
index 4eb0421..27b27e2 100644
--- a/Documentation/git-cat-file.txt
+++ b/Documentation/git-cat-file.txt
@@ -94,8 +94,10 @@
 	Instead of reading a list of objects on stdin, perform the
 	requested batch operation on all objects in the repository and
 	any alternate object stores (not just reachable objects).
-	Requires `--batch` or `--batch-check` be specified. Note that
-	the objects are visited in order sorted by their hashes.
+	Requires `--batch` or `--batch-check` be specified. By default,
+	the objects are visited in order sorted by their hashes; see
+	also `--unordered` below. Objects are presented as-is, without
+	respecting the "replace" mechanism of linkgit:git-replace[1].
 
 --buffer::
 	Normally batch output is flushed after each object is output, so
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index b1a6fe4..d473c9b 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -118,8 +118,9 @@
 -f::
 --force::
 	When switching branches, proceed even if the index or the
-	working tree differs from `HEAD`.  This is used to throw away
-	local changes.
+	working tree differs from `HEAD`, and even if there are untracked
+	files in the way.  This is used to throw away local changes and
+	any untracked files or directories that are in the way.
 +
 When checking out paths from the index, do not fail upon unmerged
 entries; instead, unmerged entries are ignored.
diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index 2ae2478..6da899c 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -235,6 +235,15 @@
 without angle brackets, and `:localpart` to get the part before the `@` symbol
 out of the trimmed email.
 
+The raw data in an object is `raw`.
+
+raw:size::
+	The raw data size of the object.
+
+Note that `--format=%(raw)` can not be used with `--python`, `--shell`, `--tcl`,
+because such language may not support arbitrary binary data in their string
+variable type.
+
 The message in a commit or a tag object is `contents`, from which
 `contents:<part>` can be used to extract various parts out of:
 
diff --git a/Documentation/git-help.txt b/Documentation/git-help.txt
index 44fe886..96d5f59 100644
--- a/Documentation/git-help.txt
+++ b/Documentation/git-help.txt
@@ -8,8 +8,10 @@
 SYNOPSIS
 --------
 [verse]
-'git help' [-a|--all [--[no-]verbose]] [-g|--guides]
-	   [-i|--info|-m|--man|-w|--web] [COMMAND|GUIDE]
+'git help' [-a|--all [--[no-]verbose]]
+	   [[-i|--info] [-m|--man] [-w|--web]] [COMMAND|GUIDE]
+'git help' [-g|--guides]
+'git help' [-c|--config]
 
 DESCRIPTION
 -----------
@@ -58,8 +60,7 @@
 
 -g::
 --guides::
-	Prints a list of the Git concept guides on the standard output. This
-	option overrides any given command or guide name.
+	Prints a list of the Git concept guides on the standard output.
 
 -i::
 --info::
diff --git a/Documentation/git-http-backend.txt b/Documentation/git-http-backend.txt
index 558966a..0c5c0dd 100644
--- a/Documentation/git-http-backend.txt
+++ b/Documentation/git-http-backend.txt
@@ -16,7 +16,9 @@
 clients accessing the repository over http:// and https:// protocols.
 The program supports clients fetching using both the smart HTTP protocol
 and the backwards-compatible dumb HTTP protocol, as well as clients
-pushing using the smart HTTP protocol.
+pushing using the smart HTTP protocol. It also supports Git's
+more-efficient "v2" protocol if properly configured; see the
+discussion of `GIT_PROTOCOL` in the ENVIRONMENT section below.
 
 It verifies that the directory has the magic file
 "git-daemon-export-ok", and it will refuse to export any Git directory
@@ -77,6 +79,18 @@
 SetEnv GIT_PROJECT_ROOT /var/www/git
 SetEnv GIT_HTTP_EXPORT_ALL
 ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/
+
+# This is not strictly necessary using Apache and a modern version of
+# git-http-backend, as the webserver will pass along the header in the
+# environment as HTTP_GIT_PROTOCOL, and http-backend will copy that into
+# GIT_PROTOCOL. But you may need this line (or something similar if you
+# are using a different webserver), or if you want to support older Git
+# versions that did not do that copying.
+#
+# Having the webserver set up GIT_PROTOCOL is perfectly fine even with
+# modern versions (and will take precedence over HTTP_GIT_PROTOCOL,
+# which means it can be used to override the client's request).
+SetEnvIf Git-Protocol ".*" GIT_PROTOCOL=$0
 ----------------------------------------------------------------
 +
 To enable anonymous read access but authenticated write access,
@@ -264,6 +278,16 @@
 specified with a unit (e.g., `100M` for 100 megabytes). The default is
 10 megabytes.
 
+Clients may probe for optional protocol capabilities (like the v2
+protocol) using the `Git-Protocol` HTTP header. In order to support
+these, the contents of that header must appear in the `GIT_PROTOCOL`
+environment variable. Most webservers will pass this header to the CGI
+via the `HTTP_GIT_PROTOCOL` variable, and `git-http-backend` will
+automatically copy that to `GIT_PROTOCOL`. However, some webservers may
+be more selective about which headers they'll pass, in which case they
+need to be configured explicitly (see the mention of `Git-Protocol` in
+the Apache config from the earlier EXAMPLES section).
+
 The backend process sets GIT_COMMITTER_NAME to '$REMOTE_USER' and
 GIT_COMMITTER_EMAIL to '$\{REMOTE_USER}@http.$\{REMOTE_ADDR\}',
 ensuring that any reflogs created by 'git-receive-pack' contain some
diff --git a/Documentation/git-index-pack.txt b/Documentation/git-index-pack.txt
index 7fa74b9..1f1e359 100644
--- a/Documentation/git-index-pack.txt
+++ b/Documentation/git-index-pack.txt
@@ -82,6 +82,12 @@
 --strict::
 	Die, if the pack contains broken objects or links.
 
+--progress-title::
+	For internal use only.
++
+Set the title of the progress bar. The title is "Receiving objects" by
+default and "Indexing objects" when `--stdin` is specified.
+
 --check-self-contained-and-connected::
 	Die if the pack contains broken links. For internal use only.
 
diff --git a/Documentation/git-maintenance.txt b/Documentation/git-maintenance.txt
index 1e738ad..e2cfb68 100644
--- a/Documentation/git-maintenance.txt
+++ b/Documentation/git-maintenance.txt
@@ -179,6 +179,17 @@
 	`maintenance.<task>.enabled` configured as `true` are considered.
 	See the 'TASKS' section for the list of accepted `<task>` values.
 
+--scheduler=auto|crontab|systemd-timer|launchctl|schtasks::
+	When combined with the `start` subcommand, specify the scheduler
+	for running the hourly, daily and weekly executions of
+	`git maintenance run`.
+	Possible values for `<scheduler>` are `auto`, `crontab`
+	(POSIX), `systemd-timer` (Linux), `launchctl` (macOS), and
+	`schtasks` (Windows). When `auto` is specified, the
+	appropriate platform-specific scheduler is used; on Linux,
+	`systemd-timer` is used if available, otherwise
+	`crontab`. Default is `auto`.
+
 
 TROUBLESHOOTING
 ---------------
@@ -277,6 +288,52 @@
 schedule.
 
 
+BACKGROUND MAINTENANCE ON LINUX SYSTEMD SYSTEMS
+-----------------------------------------------
+
+While Linux supports `cron`, depending on the distribution, `cron` may
+be an optional package not necessarily installed. On modern Linux
+distributions, systemd timers are superseding it.
+
+If user systemd timers are available, they will be used as a replacement
+of `cron`.
+
+In this case, `git maintenance start` will create user systemd timer units
+and start the timers. The current list of user-scheduled tasks can be found
+by running `systemctl --user list-timers`. The timers written by `git
+maintenance start` are similar to this:
+
+-----------------------------------------------------------------------
+$ systemctl --user list-timers
+NEXT                         LEFT          LAST                         PASSED     UNIT                         ACTIVATES
+Thu 2021-04-29 19:00:00 CEST 42min left    Thu 2021-04-29 18:00:11 CEST 17min ago  git-maintenance@hourly.timer git-maintenance@hourly.service
+Fri 2021-04-30 00:00:00 CEST 5h 42min left Thu 2021-04-29 00:00:11 CEST 18h ago    git-maintenance@daily.timer  git-maintenance@daily.service
+Mon 2021-05-03 00:00:00 CEST 3 days left   Mon 2021-04-26 00:00:11 CEST 3 days ago git-maintenance@weekly.timer git-maintenance@weekly.service
+-----------------------------------------------------------------------
+
+One timer is registered for each `--schedule=<frequency>` option.
+
+The definition of the systemd units can be inspected in the following files:
+
+-----------------------------------------------------------------------
+~/.config/systemd/user/git-maintenance@.timer
+~/.config/systemd/user/git-maintenance@.service
+~/.config/systemd/user/timers.target.wants/git-maintenance@hourly.timer
+~/.config/systemd/user/timers.target.wants/git-maintenance@daily.timer
+~/.config/systemd/user/timers.target.wants/git-maintenance@weekly.timer
+-----------------------------------------------------------------------
+
+`git maintenance start` will overwrite these files and start the timer
+again with `systemctl --user`, so any customization should be done by
+creating a drop-in file, i.e. a `.conf` suffixed file in the
+`~/.config/systemd/user/git-maintenance@.service.d` directory.
+
+`git maintenance stop` will stop the user systemd timers and delete
+the above mentioned files.
+
+For more details, see `systemd.timer(5)`.
+
+
 BACKGROUND MAINTENANCE ON MACOS SYSTEMS
 ---------------------------------------
 
diff --git a/Documentation/git-multi-pack-index.txt b/Documentation/git-multi-pack-index.txt
index ffd601b..c588fb9 100644
--- a/Documentation/git-multi-pack-index.txt
+++ b/Documentation/git-multi-pack-index.txt
@@ -9,8 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git multi-pack-index' [--object-dir=<dir>] [--[no-]progress]
-	[--preferred-pack=<pack>] <subcommand>
+'git multi-pack-index' [--object-dir=<dir>] [--[no-]bitmap] <sub-command>
 
 DESCRIPTION
 -----------
@@ -23,10 +22,13 @@
 	Use given directory for the location of Git objects. We check
 	`<dir>/packs/multi-pack-index` for the current MIDX file, and
 	`<dir>/packs` for the pack-files to index.
++
+`<dir>` must be an alternate of the current repository.
 
 --[no-]progress::
 	Turn progress on/off explicitly. If neither is specified, progress is
-	shown if standard error is connected to a terminal.
+	shown if standard error is connected to a terminal. Supported by
+	sub-commands `write`, `verify`, `expire`, and `repack.
 
 The following subcommands are available:
 
@@ -37,9 +39,31 @@
 --
 	--preferred-pack=<pack>::
 		Optionally specify the tie-breaking pack used when
-		multiple packs contain the same object. If not given,
-		ties are broken in favor of the pack with the lowest
-		mtime.
+		multiple packs contain the same object. `<pack>` must
+		contain at least one object. If not given, ties are
+		broken in favor of the pack with the lowest mtime.
+
+	--[no-]bitmap::
+		Control whether or not a multi-pack bitmap is written.
+
+	--stdin-packs::
+		Write a multi-pack index containing only the set of
+		line-delimited pack index basenames provided over stdin.
+
+	--refs-snapshot=<path>::
+		With `--bitmap`, optionally specify a file which
+		contains a "refs snapshot" taken prior to repacking.
++
+A reference snapshot is composed of line-delimited OIDs corresponding to
+the reference tips, usually taken by `git repack` prior to generating a
+new pack. A line may optionally start with a `+` character to indicate
+that the reference which corresponds to that OID is "preferred" (see
+linkgit:git-config[1]'s `pack.preferBitmapTips`.)
++
+The file given at `<path>` is expected to be readable, and can contain
+duplicates. (If a given OID is given more than once, it is marked as
+preferred if at least one instance of it begins with the special `+`
+marker).
 --
 
 verify::
@@ -75,19 +99,26 @@
 EXAMPLES
 --------
 
-* Write a MIDX file for the packfiles in the current .git folder.
+* Write a MIDX file for the packfiles in the current `.git` directory.
 +
 -----------------------------------------------
 $ git multi-pack-index write
 -----------------------------------------------
 
+* Write a MIDX file for the packfiles in the current `.git` directory with a
+corresponding bitmap.
++
+-------------------------------------------------------------
+$ git multi-pack-index write --preferred-pack=<pack> --bitmap
+-------------------------------------------------------------
+
 * Write a MIDX file for the packfiles in an alternate object store.
 +
 -----------------------------------------------
 $ git multi-pack-index --object-dir <alt> write
 -----------------------------------------------
 
-* Verify the MIDX file for the packfiles in the current .git folder.
+* Verify the MIDX file for the packfiles in the current `.git` directory.
 +
 -----------------------------------------------
 $ git multi-pack-index verify
diff --git a/Documentation/git-pull.txt b/Documentation/git-pull.txt
index aef757e..0e14f8b 100644
--- a/Documentation/git-pull.txt
+++ b/Documentation/git-pull.txt
@@ -105,7 +105,7 @@
 include::merge-options.txt[]
 
 -r::
---rebase[=false|true|merges|preserve|interactive]::
+--rebase[=false|true|merges|interactive]::
 	When true, rebase the current branch on top of the upstream
 	branch after fetching. If there is a remote-tracking branch
 	corresponding to the upstream branch and the upstream branch
@@ -116,10 +116,6 @@
 the local merge commits are included in the rebase (see
 linkgit:git-rebase[1] for details).
 +
-When set to `preserve` (deprecated in favor of `merges`), rebase with the
-`--preserve-merges` option passed to `git rebase` so that locally created
-merge commits will not be flattened.
-+
 When false, merge the upstream branch into the current branch.
 +
 When `interactive`, enable the interactive mode of rebase.
diff --git a/Documentation/git-read-tree.txt b/Documentation/git-read-tree.txt
index 5fa8bab..8c3aceb 100644
--- a/Documentation/git-read-tree.txt
+++ b/Documentation/git-read-tree.txt
@@ -10,8 +10,7 @@
 --------
 [verse]
 'git read-tree' [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>]
-		[-u [--exclude-per-directory=<gitignore>] | -i]]
-		[--index-output=<file>] [--no-sparse-checkout]
+		[-u | -i]] [--index-output=<file>] [--no-sparse-checkout]
 		(--empty | <tree-ish1> [<tree-ish2> [<tree-ish3>]])
 
 
@@ -39,8 +38,9 @@
 
 --reset::
 	Same as -m, except that unmerged entries are discarded instead
-	of failing. When used with `-u`, updates leading to loss of
-	working tree changes will not abort the operation.
+	of failing.  When used with `-u`, updates leading to loss of
+	working tree changes or untracked files or directories will not
+	abort the operation.
 
 -u::
 	After a successful merge, update the files in the work
@@ -88,21 +88,6 @@
 	The command will refuse to overwrite entries that already
 	existed in the original index file.
 
---exclude-per-directory=<gitignore>::
-	When running the command with `-u` and `-m` options, the
-	merge result may need to overwrite paths that are not
-	tracked in the current branch.  The command usually
-	refuses to proceed with the merge to avoid losing such a
-	path.  However this safety valve sometimes gets in the
-	way.  For example, it often happens that the other
-	branch added a file that used to be a generated file in
-	your branch, and the safety valve triggers when you try
-	to switch to that branch after you ran `make` but before
-	running `make clean` to remove the generated file.  This
-	option tells the command to read per-directory exclude
-	file (usually '.gitignore') and allows such an untracked
-	but explicitly ignored file to be overwritten.
-
 --index-output=<file>::
 	Instead of writing the results out to `$GIT_INDEX_FILE`,
 	write the resulting index in the named file.  While the
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 73d49ec..a1af21f 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -79,9 +79,10 @@
 
 If the upstream branch already contains a change you have made (e.g.,
 because you mailed a patch which was applied upstream), then that commit
-will be skipped. For example, running `git rebase master` on the
-following history (in which `A'` and `A` introduce the same set of changes,
-but have different committer information):
+will be skipped and warnings will be issued (if the `merge` backend is
+used).  For example, running `git rebase master` on the following
+history (in which `A'` and `A` introduce the same set of changes, but
+have different committer information):
 
 ------------
           A---B---C topic
@@ -312,7 +313,10 @@
 By default (or if `--no-reapply-cherry-picks` is given), these commits
 will be automatically dropped.  Because this necessitates reading all
 upstream commits, this can be expensive in repos with a large number
-of upstream commits that need to be read.
+of upstream commits that need to be read.  When using the `merge`
+backend, warnings will be issued for each dropped commit (unless
+`--quiet` is given). Advice will also be issued unless
+`advice.skippedCherryPicks` is set to false (see linkgit:git-config[1]).
 +
 `--reapply-cherry-picks` allows rebase to forgo reading all upstream
 commits, potentially improving performance.
@@ -352,8 +356,8 @@
 
 -s <strategy>::
 --strategy=<strategy>::
-	Use the given merge strategy, instead of the default
-	`recursive`.  This implies `--merge`.
+	Use the given merge strategy, instead of the default `ort`.
+	This implies `--merge`.
 +
 Because 'git rebase' replays each commit from the working branch
 on top of the <upstream> branch using the given strategy, using
@@ -366,7 +370,7 @@
 --strategy-option=<strategy-option>::
 	Pass the <strategy-option> through to the merge strategy.
 	This implies `--merge` and, if no strategy has been
-	specified, `-s recursive`.  Note the reversal of 'ours' and
+	specified, `-s ort`.  Note the reversal of 'ours' and
 	'theirs' as noted above for the `-m` option.
 +
 See also INCOMPATIBLE OPTIONS below.
@@ -442,7 +446,8 @@
 ends up being empty, the <upstream> will be used as a fallback.
 +
 If <upstream> is given on the command line, then the default is
-`--no-fork-point`, otherwise the default is `--fork-point`.
+`--no-fork-point`, otherwise the default is `--fork-point`. See also
+`rebase.forkpoint` in linkgit:git-config[1].
 +
 If your branch was based on <upstream> but <upstream> was rewound and
 your branch contains commits which were dropped, this option can be used
@@ -522,29 +527,12 @@
 the `rebase-cousins` mode is turned on, such commits are instead rebased
 onto `<upstream>` (or `<onto>`, if specified).
 +
-The `--rebase-merges` mode is similar in spirit to the deprecated
-`--preserve-merges` but works with interactive rebases,
-where commits can be reordered, inserted and dropped at will.
-+
 It is currently only possible to recreate the merge commits using the
-`recursive` merge strategy; different merge strategies can be used only via
+`ort` merge strategy; different merge strategies can be used only via
 explicit `exec git merge -s <strategy> [...]` commands.
 +
 See also REBASING MERGES and INCOMPATIBLE OPTIONS below.
 
--p::
---preserve-merges::
-	[DEPRECATED: use `--rebase-merges` instead] Recreate merge commits
-	instead of flattening the history by replaying commits a merge commit
-	introduces. Merge conflict resolutions or manual amendments to merge
-	commits are not preserved.
-+
-This uses the `--interactive` machinery internally, but combining it
-with the `--interactive` option explicitly is generally not a good
-idea unless you know what you are doing (see BUGS below).
-+
-See also INCOMPATIBLE OPTIONS below.
-
 -x <cmd>::
 --exec <cmd>::
 	Append "exec <cmd>" after each line creating a commit in the
@@ -576,9 +564,6 @@
 	the root commit(s) on a branch.  When used with --onto, it
 	will skip changes already contained in <newbase> (instead of
 	<upstream>) whereas without --onto it will operate on every change.
-	When used together with both --onto and --preserve-merges,
-	'all' root commits will be rewritten to have <newbase> as parent
-	instead.
 +
 See also INCOMPATIBLE OPTIONS below.
 
@@ -640,7 +625,6 @@
  * --allow-empty-message
  * --[no-]autosquash
  * --rebase-merges
- * --preserve-merges
  * --interactive
  * --exec
  * --no-keep-empty
@@ -651,13 +635,6 @@
 
 In addition, the following pairs of options are incompatible:
 
- * --preserve-merges and --interactive
- * --preserve-merges and --signoff
- * --preserve-merges and --rebase-merges
- * --preserve-merges and --empty=
- * --preserve-merges and --ignore-whitespace
- * --preserve-merges and --committer-date-is-author-date
- * --preserve-merges and --ignore-date
  * --keep-base and --onto
  * --keep-base and --root
  * --fork-point and --root
@@ -1216,16 +1193,16 @@
 If a `merge` command fails for any reason other than merge conflicts (i.e.
 when the merge operation did not even start), it is rescheduled immediately.
 
-By default, the `merge` command will use the `recursive` merge
-strategy for regular merges, and `octopus` for octopus merges.  One
-can specify a default strategy for all merges using the `--strategy`
-argument when invoking rebase, or can override specific merges in the
-interactive list of commands by using an `exec` command to call `git
-merge` explicitly with a `--strategy` argument.  Note that when
-calling `git merge` explicitly like this, you can make use of the fact
-that the labels are worktree-local refs (the ref `refs/rewritten/onto`
-would correspond to the label `onto`, for example) in order to refer
-to the branches you want to merge.
+By default, the `merge` command will use the `ort` merge strategy for
+regular merges, and `octopus` for octopus merges.  One can specify a
+default strategy for all merges using the `--strategy` argument when
+invoking rebase, or can override specific merges in the interactive
+list of commands by using an `exec` command to call `git merge`
+explicitly with a `--strategy` argument.  Note that when calling `git
+merge` explicitly like this, you can make use of the fact that the
+labels are worktree-local refs (the ref `refs/rewritten/onto` would
+correspond to the label `onto`, for example) in order to refer to the
+branches you want to merge.
 
 Note: the first command (`label onto`) labels the revision onto which
 the commits are rebased; The name `onto` is just a convention, as a nod
@@ -1275,29 +1252,6 @@
 include::config/rebase.txt[]
 include::config/sequencer.txt[]
 
-BUGS
-----
-The todo list presented by the deprecated `--preserve-merges --interactive`
-does not represent the topology of the revision graph (use `--rebase-merges`
-instead).  Editing commits and rewording their commit messages should work
-fine, but attempts to reorder commits tend to produce counterintuitive results.
-Use `--rebase-merges` in such scenarios instead.
-
-For example, an attempt to rearrange
-------------
-1 --- 2 --- 3 --- 4 --- 5
-------------
-to
-------------
-1 --- 2 --- 4 --- 3 --- 5
-------------
-by moving the "pick 4" line will result in the following history:
-------------
-	3
-       /
-1 --- 2 --- 4 --- 5
-------------
-
 GIT
 ---
 Part of the linkgit:git[1] suite
diff --git a/Documentation/git-receive-pack.txt b/Documentation/git-receive-pack.txt
index 25702ed..014a784 100644
--- a/Documentation/git-receive-pack.txt
+++ b/Documentation/git-receive-pack.txt
@@ -41,6 +41,11 @@
 <directory>::
 	The repository to sync into.
 
+--http-backend-info-refs::
+	Used by linkgit:git-http-backend[1] to serve up
+	`$GIT_URL/info/refs?service=git-receive-pack` requests. See
+	`--http-backend-info-refs` in linkgit:git-upload-pack[1].
+
 PRE-RECEIVE HOOK
 ----------------
 Before any ref is updated, if $GIT_DIR/hooks/pre-receive file exists
diff --git a/Documentation/git-repack.txt b/Documentation/git-repack.txt
index 24c00c9..7183fb4 100644
--- a/Documentation/git-repack.txt
+++ b/Documentation/git-repack.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git repack' [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [--window=<n>] [--depth=<n>] [--threads=<n>] [--keep-pack=<pack-name>]
+'git repack' [-a] [-A] [-d] [-f] [-F] [-l] [-n] [-q] [-b] [-m] [--window=<n>] [--depth=<n>] [--threads=<n>] [--keep-pack=<pack-name>] [--write-midx]
 
 DESCRIPTION
 -----------
@@ -128,10 +128,11 @@
 -b::
 --write-bitmap-index::
 	Write a reachability bitmap index as part of the repack. This
-	only makes sense when used with `-a` or `-A`, as the bitmaps
+	only makes sense when used with `-a`, `-A` or `-m`, as the bitmaps
 	must be able to refer to all reachable objects. This option
-	overrides the setting of `repack.writeBitmaps`.  This option
-	has no effect if multiple packfiles are created.
+	overrides the setting of `repack.writeBitmaps`. This option
+	has no effect if multiple packfiles are created, unless writing a
+	MIDX (in which case a multi-pack bitmap is created).
 
 --pack-kept-objects::
 	Include objects in `.keep` files when repacking.  Note that we
@@ -189,6 +190,15 @@
 to change in the future. This option (implying a drastically different
 repack mode) is not guaranteed to work with all other combinations of
 option to `git repack`.
++
+When writing a multi-pack bitmap, `git repack` selects the largest resulting
+pack as the preferred pack for object selection by the MIDX (see
+linkgit:git-multi-pack-index[1]).
+
+-m::
+--write-midx::
+	Write a multi-pack index (see linkgit:git-multi-pack-index[1])
+	containing the non-redundant packs.
 
 CONFIGURATION
 -------------
diff --git a/Documentation/git-reset.txt b/Documentation/git-reset.txt
index 252e2d4..6f7685f 100644
--- a/Documentation/git-reset.txt
+++ b/Documentation/git-reset.txt
@@ -69,7 +69,8 @@
 
 --hard::
 	Resets the index and working tree. Any changes to tracked files in the
-	working tree since `<commit>` are discarded.
+	working tree since `<commit>` are discarded.  Any untracked files or
+	directories in the way of writing any tracked files are simply deleted.
 
 --merge::
 	Resets the index and updates the files in the working tree that are
diff --git a/Documentation/git-rm.txt b/Documentation/git-rm.txt
index 26e9b28..81bc23f 100644
--- a/Documentation/git-rm.txt
+++ b/Documentation/git-rm.txt
@@ -72,6 +72,12 @@
 --ignore-unmatch::
 	Exit with a zero status even if no files matched.
 
+--sparse::
+	Allow updating index entries outside of the sparse-checkout cone.
+	Normally, `git rm` refuses to update index entries whose paths do
+	not fit within the sparse-checkout cone. See
+	linkgit:git-sparse-checkout[1] for more.
+
 -q::
 --quiet::
 	`git rm` normally outputs one line (in the form of an `rm` command)
diff --git a/Documentation/git-send-pack.txt b/Documentation/git-send-pack.txt
index 44fd146..be41f11 100644
--- a/Documentation/git-send-pack.txt
+++ b/Documentation/git-send-pack.txt
@@ -9,10 +9,10 @@
 SYNOPSIS
 --------
 [verse]
-'git send-pack' [--all] [--dry-run] [--force] [--receive-pack=<git-receive-pack>]
+'git send-pack' [--dry-run] [--force] [--receive-pack=<git-receive-pack>]
 		[--verbose] [--thin] [--atomic]
 		[--[no-]signed|--signed=(true|false|if-asked)]
-		[<host>:]<directory> [<ref>...]
+		[<host>:]<directory> (--all | <ref>...)
 
 DESCRIPTION
 -----------
diff --git a/Documentation/git-sparse-checkout.txt b/Documentation/git-sparse-checkout.txt
index fdcf43f..42056ee 100644
--- a/Documentation/git-sparse-checkout.txt
+++ b/Documentation/git-sparse-checkout.txt
@@ -210,6 +210,16 @@
 'git sparse-checkout set' command to reflect the expected cone in the working
 directory.
 
+When changing the sparse-checkout patterns in cone mode, Git will inspect each
+tracked directory that is not within the sparse-checkout cone to see if it
+contains any untracked files. If all of those files are ignored due to the
+`.gitignore` patterns, then the directory will be deleted. If any of the
+untracked files within that directory is not ignored, then no deletions will
+occur within that directory and a warning message will appear. If these files
+are important, then reset your sparse-checkout definition so they are included,
+use `git add` and `git commit` to store them, then remove any remaining files
+manually to ensure Git can behave optimally.
+
 
 SUBMODULES
 ----------
diff --git a/Documentation/git-status.txt b/Documentation/git-status.txt
index 83f38e3..4a2c3e0 100644
--- a/Documentation/git-status.txt
+++ b/Documentation/git-status.txt
@@ -207,26 +207,29 @@
 
 * ' ' = unmodified
 * 'M' = modified
+* 'T' = file type changed (regular file, symbolic link or submodule)
 * 'A' = added
 * 'D' = deleted
 * 'R' = renamed
-* 'C' = copied
+* 'C' = copied (if config option status.renames is set to "copies")
 * 'U' = updated but unmerged
 
 ....
 X          Y     Meaning
 -------------------------------------------------
 	 [AMD]   not updated
-M        [ MD]   updated in index
-A        [ MD]   added to index
+M        [ MTD]  updated in index
+T        [ MTD]  type changed in index
+A        [ MTD]  added to index
 D                deleted from index
-R        [ MD]   renamed in index
-C        [ MD]   copied in index
-[MARC]           index and work tree matches
-[ MARC]     M    work tree changed since index
-[ MARC]     D    deleted in work tree
-[ D]        R    renamed in work tree
-[ D]        C    copied in work tree
+R        [ MTD]  renamed in index
+C        [ MTD]  copied in index
+[MTARC]          index and work tree matches
+[ MTARC]    M    work tree changed since index
+[ MTARC]    T    type changed in work tree since index
+[ MTARC]    D    deleted in work tree
+	    R    renamed in work tree
+	    C    copied in work tree
 -------------------------------------------------
 D           D    unmerged, both deleted
 A           U    unmerged, added by us
@@ -363,7 +366,7 @@
 Unmerged entries have the following format; the first character is
 a "u" to distinguish from ordinary changed entries.
 
-    u <xy> <sub> <m1> <m2> <m3> <mW> <h1> <h2> <h3> <path>
+    u <XY> <sub> <m1> <m2> <m3> <mW> <h1> <h2> <h3> <path>
 
 ....
 Field       Meaning
diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt
index d5776ff..222b556 100644
--- a/Documentation/git-svn.txt
+++ b/Documentation/git-svn.txt
@@ -678,7 +678,6 @@
 --strategy=<strategy>::
 -p::
 --rebase-merges::
---preserve-merges (DEPRECATED)::
 	These are only used with the 'dcommit' and 'rebase' commands.
 +
 Passed directly to 'git rebase' when using 'dcommit' if a
diff --git a/Documentation/git-upload-pack.txt b/Documentation/git-upload-pack.txt
index 9822c1e..8f87b23 100644
--- a/Documentation/git-upload-pack.txt
+++ b/Documentation/git-upload-pack.txt
@@ -36,14 +36,26 @@
 	This fits with the HTTP POST request processing model where
 	a program may read the request, write a response, and must exit.
 
---advertise-refs::
-	Only the initial ref advertisement is output, and the program exits
-	immediately. This fits with the HTTP GET request model, where
-	no request content is received but a response must be produced.
+--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
+	linkgit:git-receive-pack[1].
 
 <directory>::
 	The repository to sync from.
 
+ENVIRONMENT
+-----------
+
+`GIT_PROTOCOL`::
+	Internal variable used for handshaking the wire protocol. Server
+	admins may need to configure some transports to allow this
+	variable to be passed. See the discussion in linkgit:git[1].
+
 SEE ALSO
 --------
 linkgit:gitnamespaces[7]
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 95fe6f3..281c5f8 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -42,7 +42,7 @@
 --version::
 	Prints the Git suite version that the 'git' program came from.
 +
-This option is internaly converted to `git version ...` and accepts
+This option is internally converted to `git version ...` and accepts
 the same options as the linkgit:git-version[1] command. If `--help` is
 also given, it takes precedence over `--version`.
 
@@ -867,15 +867,16 @@
 	end user, to be recorded in the body of the reflog.
 
 `GIT_REF_PARANOIA`::
-	If set to `1`, include broken or badly named refs when iterating
-	over lists of refs. In a normal, non-corrupted repository, this
-	does nothing. However, enabling it may help git to detect and
-	abort some operations in the presence of broken refs. Git sets
-	this variable automatically when performing destructive
-	operations like linkgit:git-prune[1]. You should not need to set
-	it yourself unless you want to be paranoid about making sure
-	an operation has touched every ref (e.g., because you are
-	cloning a repository to make a backup).
+	If set to `0`, ignore broken or badly named refs when iterating
+	over lists of refs. Normally Git will try to include any such
+	refs, which may cause some operations to fail. This is usually
+	preferable, as potentially destructive operations (e.g.,
+	linkgit:git-prune[1]) are better off aborting rather than
+	ignoring broken refs (and thus considering the history they
+	point to as not worth saving). The default value is `1` (i.e.,
+	be paranoid about detecting and aborting all operations). You
+	should not normally need to set this to `0`, but it may be
+	useful when trying to salvage data from a corrupted repository.
 
 `GIT_ALLOW_PROTOCOL`::
 	If set to a colon-separated list of protocols, behave as if
@@ -898,6 +899,21 @@
 	Contains a colon ':' separated list of keys with optional values
 	'key[=value]'.  Presence of unknown keys and values must be
 	ignored.
++
+Note that servers may need to be configured to allow this variable to
+pass over some transports. It will be propagated automatically when
+accessing local repositories (i.e., `file://` or a filesystem path), as
+well as over the `git://` protocol. For git-over-http, it should work
+automatically in most configurations, but see the discussion in
+linkgit:git-http-backend[1]. For git-over-ssh, the ssh server may need
+to be configured to allow clients to pass this variable (e.g., by using
+`AcceptEnv GIT_PROTOCOL` with OpenSSH).
++
+This configuration is optional. If the variable is not propagated, then
+clients will fall back to the original "v0" protocol (but may miss out
+on some performance improvements or features). This variable currently
+only affects clones and fetches; it is not yet used for pushes (but may
+be in the future).
 
 `GIT_OPTIONAL_LOCKS`::
 	If set to `0`, Git will complete any requested operation without
diff --git a/Documentation/gitfaq.txt b/Documentation/gitfaq.txt
index afdaeab..8c1f2d5 100644
--- a/Documentation/gitfaq.txt
+++ b/Documentation/gitfaq.txt
@@ -275,7 +275,7 @@
 
 [[merge-two-revert-one]]
 If I make a change on two branches but revert it on one, why does the merge of those branches include the change?::
-	By default, when Git does a merge, it uses a strategy called the recursive
+	By default, when Git does a merge, it uses a strategy called the `ort`
 	strategy, which does a fancy three-way merge.  In such a case, when Git
 	performs the merge, it considers exactly three points: the two heads and a
 	third point, called the _merge base_, which is usually the common ancestor of
diff --git a/Documentation/gitignore.txt b/Documentation/gitignore.txt
index f8a1fc2..f2738b1 100644
--- a/Documentation/gitignore.txt
+++ b/Documentation/gitignore.txt
@@ -155,7 +155,7 @@
 EXAMPLES
 --------
 
- - The pattern `hello.*` matches any file or folder
+ - The pattern `hello.*` matches any file or directory
    whose name begins with `hello.`. If one wants to restrict
    this only to the directory and not in its subdirectories,
    one can prepend the pattern with a slash, i.e. `/hello.*`;
diff --git a/Documentation/gitweb.txt b/Documentation/gitweb.txt
index 3cc9b03..7cee9d3 100644
--- a/Documentation/gitweb.txt
+++ b/Documentation/gitweb.txt
@@ -547,7 +547,7 @@
     # make the front page an internal rewrite to the gitweb script
     RewriteRule ^/$  /cgi-bin/gitweb.cgi  [QSA,L,PT]
 
-    # look for a public_git folder in unix users' home
+    # look for a public_git directory in unix users' home
     # http://git.example.org/~<user>/
     RewriteRule ^/\~([^\/]+)(/|/gitweb.cgi)?$	/cgi-bin/gitweb.cgi \
 		[QSA,E=GITWEB_PROJECTROOT:/home/$1/public_git/,L,PT]
diff --git a/Documentation/lint-gitlink.perl b/Documentation/lint-gitlink.perl
index b22a367..1c61dd9 100755
--- a/Documentation/lint-gitlink.perl
+++ b/Documentation/lint-gitlink.perl
@@ -5,11 +5,12 @@
 
 # Parse arguments, a simple state machine for input like:
 #
-# howto/*.txt config/*.txt --section=1 git.txt git-add.txt [...] --to-lint git-add.txt a-file.txt [...]
+# <file-to-check.txt> <valid-files-to-link-to> --section=1 git.txt git-add.txt [...] --to-lint git-add.txt a-file.txt [...]
 my %TXT;
 my %SECTION;
 my $section;
 my $lint_these = 0;
+my $to_check = shift @ARGV;
 for my $arg (@ARGV) {
 	if (my ($sec) = $arg =~ /^--section=(\d+)$/s) {
 		$section = $sec;
@@ -30,13 +31,14 @@
 	my ($pos, $line, $target, $msg) = @_;
 	substr($line, $pos) = "' <-- HERE";
 	$line =~ s/^\s+//;
-	print "$ARGV:$.: error: $target: $msg, shown with 'HERE' below:\n";
-	print "$ARGV:$.:\t'$line\n";
+	print STDERR "$ARGV:$.: error: $target: $msg, shown with 'HERE' below:\n";
+	print STDERR "$ARGV:$.:\t'$line\n";
 	$exit_code = 1;
 }
 
 @ARGV = sort values %TXT;
-die "BUG: Nothing to process!" unless @ARGV;
+die "BUG: No list of valid linkgit:* files given" unless @ARGV;
+@ARGV = $to_check;
 while (<>) {
 	my $line = $_;
 	while ($line =~ m/linkgit:((.*?)\[(\d)\])/g) {
diff --git a/Documentation/lint-man-end-blurb.perl b/Documentation/lint-man-end-blurb.perl
index d69312e..6bdb13a 100755
--- a/Documentation/lint-man-end-blurb.perl
+++ b/Documentation/lint-man-end-blurb.perl
@@ -6,7 +6,7 @@
 my $exit_code = 0;
 sub report {
 	my ($target, $msg) = @_;
-	print "error: $target: $msg\n";
+	print STDERR "error: $target: $msg\n";
 	$exit_code = 1;
 }
 
diff --git a/Documentation/lint-man-section-order.perl b/Documentation/lint-man-section-order.perl
index b05f915..425377d 100755
--- a/Documentation/lint-man-section-order.perl
+++ b/Documentation/lint-man-section-order.perl
@@ -46,7 +46,7 @@
 my $exit_code = 0;
 sub report {
 	my ($msg) = @_;
-	print "$ARGV:$.: $msg\n";
+	print STDERR "$ARGV:$.: $msg\n";
 	$exit_code = 1;
 }
 
diff --git a/Documentation/merge-options.txt b/Documentation/merge-options.txt
index 86f277a..61ec157 100644
--- a/Documentation/merge-options.txt
+++ b/Documentation/merge-options.txt
@@ -144,7 +144,7 @@
 	Use the given merge strategy; can be supplied more than
 	once to specify them in the order they should be tried.
 	If there is no `-s` option, a built-in list of strategies
-	is used instead (`recursive` when merging a single head,
+	is used instead (`ort` when merging a single head,
 	`octopus` otherwise).
 
 -X <option>::
diff --git a/Documentation/merge-strategies.txt b/Documentation/merge-strategies.txt
index 210f0f8..5fc54ec 100644
--- a/Documentation/merge-strategies.txt
+++ b/Documentation/merge-strategies.txt
@@ -6,21 +6,23 @@
 can also take their own options, which can be passed by giving `-X<option>`
 arguments to `git merge` and/or `git pull`.
 
-recursive::
-	This can only resolve two heads using a 3-way merge
-	algorithm.  When there is more than one common
-	ancestor that can be used for 3-way merge, it creates a
-	merged tree of the common ancestors and uses that as
-	the reference tree for the 3-way merge.  This has been
-	reported to result in fewer merge conflicts without
-	causing mismerges by tests done on actual merge commits
-	taken from Linux 2.6 kernel development history.
-	Additionally this can detect and handle merges involving
-	renames.  It does not make use of detected copies.  This
-	is the default merge strategy when pulling or merging one
-	branch.
+ort::
+	This is the default merge strategy when pulling or merging one
+	branch.  This strategy can only resolve two heads using a
+	3-way merge algorithm.  When there is more than one common
+	ancestor that can be used for 3-way merge, it creates a merged
+	tree of the common ancestors and uses that as the reference
+	tree for the 3-way merge.  This has been reported to result in
+	fewer merge conflicts without causing mismerges by tests done
+	on actual merge commits taken from Linux 2.6 kernel
+	development history.  Additionally this strategy can detect
+	and handle merges involving renames.  It does not make use of
+	detected copies.  The name for this algorithm is an acronym
+	("Ostensibly Recursive's Twin") and came from the fact that it
+	was written as a replacement for the previous default
+	algorithm, `recursive`.
 +
-The 'recursive' strategy can take the following options:
+The 'ort' strategy can take the following options:
 
 ours;;
 	This option forces conflicting hunks to be auto-resolved cleanly by
@@ -36,16 +38,6 @@
 	This is the opposite of 'ours'; note that, unlike 'ours', there is
 	no 'theirs' merge strategy to confuse this merge option with.
 
-patience;;
-	Deprecated synonym for `diff-algorithm=patience`.
-
-diff-algorithm=[patience|minimal|histogram|myers];;
-	Use a different diff algorithm while merging, which can help
-	avoid mismerges that occur due to unimportant matching lines
-	(such as braces from distinct functions).  See also
-	linkgit:git-diff[1] `--diff-algorithm`.  Defaults to the
-	`diff.algorithm` config setting.
-
 ignore-space-change;;
 ignore-all-space;;
 ignore-space-at-eol;;
@@ -74,11 +66,6 @@
 	Disables the `renormalize` option.  This overrides the
 	`merge.renormalize` configuration variable.
 
-no-renames;;
-	Turn off rename detection. This overrides the `merge.renames`
-	configuration variable.
-	See also linkgit:git-diff[1] `--no-renames`.
-
 find-renames[=<n>];;
 	Turn on rename detection, optionally setting the similarity
 	threshold.  This is the default. This overrides the
@@ -95,19 +82,39 @@
 	is prefixed (or stripped from the beginning) to make the shape of
 	two trees to match.
 
-ort::
-	This is meant as a drop-in replacement for the `recursive`
-	algorithm (as reflected in its acronym -- "Ostensibly
-	Recursive's Twin"), and will likely replace it in the future.
-	It fixes corner cases that the `recursive` strategy handles
-	suboptimally, and is significantly faster in large
-	repositories -- especially when many renames are involved.
+recursive::
+	This can only resolve two heads using a 3-way merge
+	algorithm.  When there is more than one common
+	ancestor that can be used for 3-way merge, it creates a
+	merged tree of the common ancestors and uses that as
+	the reference tree for the 3-way merge.  This has been
+	reported to result in fewer merge conflicts without
+	causing mismerges by tests done on actual merge commits
+	taken from Linux 2.6 kernel development history.
+	Additionally this can detect and handle merges involving
+	renames.  It does not make use of detected copies.  This was
+	the default strategy for resolving two heads from Git v0.99.9k
+	until v2.33.0.
 +
-The `ort` strategy takes all the same options as `recursive`.
-However, it ignores three of those options: `no-renames`,
-`patience` and `diff-algorithm`.  It always runs with rename
-detection (it handles it much faster than `recursive` does), and
-it specifically uses `diff-algorithm=histogram`.
+The 'recursive' strategy takes the same options as 'ort'.  However,
+there are three additional options that 'ort' ignores (not documented
+above) that are potentially useful with the 'recursive' strategy:
+
+patience;;
+	Deprecated synonym for `diff-algorithm=patience`.
+
+diff-algorithm=[patience|minimal|histogram|myers];;
+	Use a different diff algorithm while merging, which can help
+	avoid mismerges that occur due to unimportant matching lines
+	(such as braces from distinct functions).  See also
+	linkgit:git-diff[1] `--diff-algorithm`.  Note that `ort`
+	specifically uses `diff-algorithm=histogram`, while `recursive`
+	defaults to the `diff.algorithm` config setting.
+
+no-renames;;
+	Turn off rename detection. This overrides the `merge.renames`
+	configuration variable.
+	See also linkgit:git-diff[1] `--no-renames`.
 
 resolve::
 	This can only resolve two heads (i.e. the current branch
@@ -131,13 +138,13 @@
 	the 'recursive' merge strategy.
 
 subtree::
-	This is a modified recursive strategy. When merging trees A and
+	This is a modified `ort` strategy. When merging trees A and
 	B, if B corresponds to a subtree of A, B is first adjusted to
 	match the tree structure of A, instead of reading the trees at
 	the same level. This adjustment is also done to the common
 	ancestor tree.
 
-With the strategies that use 3-way merge (including the default, 'recursive'),
+With the strategies that use 3-way merge (including the default, 'ort'),
 if a change is made on both branches, but later reverted on one of the
 branches, that change will be present in the merged result; some people find
 this behavior confusing.  It occurs because only the heads and the merge base
diff --git a/Documentation/pretty-options.txt b/Documentation/pretty-options.txt
index b3af850..dc685be 100644
--- a/Documentation/pretty-options.txt
+++ b/Documentation/pretty-options.txt
@@ -41,8 +41,8 @@
 	in `X` and we are outputting in `X`, we will output the object
 	verbatim; this means that invalid sequences in the original
 	commit may be copied to the output. Likewise, if iconv(3) fails
-	to convert the commit, we will output the original object
-	verbatim, along with a warning.
+	to convert the commit, we will quietly output the original
+	object verbatim.
 
 --expand-tabs=<n>::
 --expand-tabs::
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 24569b0..b7bd27e 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -968,6 +968,11 @@
 	objects.
 endif::git-rev-list[]
 
+--unsorted-input::
+	Show commits in the order they were given on the command line instead
+	of sorting them in reverse chronological order by commit time. Cannot
+	be combined with `--no-walk` or `--no-walk=sorted`.
+
 --no-walk[=(sorted|unsorted)]::
 	Only show the given commits, but do not traverse their ancestors.
 	This has no effect if a range is specified. If the argument
@@ -975,7 +980,8 @@
 	given on the command line. Otherwise (if `sorted` or no argument
 	was given), the commits are shown in reverse chronological order
 	by commit time.
-	Cannot be combined with `--graph`.
+	Cannot be combined with `--graph`. Cannot be combined with
+	`--unsorted-input` if `sorted` or no argument was given.
 
 --do-walk::
 	Overrides a previous `--no-walk`.
diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt
index 5a60bbf..acfd5dc 100644
--- a/Documentation/technical/api-parse-options.txt
+++ b/Documentation/technical/api-parse-options.txt
@@ -198,11 +198,6 @@
 	The filename will be prefixed by passing the filename along with
 	the prefix argument of `parse_options()` to `prefix_filename()`.
 
-`OPT_ARGUMENT(long, &int_var, description)`::
-	Introduce a long-option argument that will be kept in `argv[]`.
-	If this option was seen, `int_var` will be set to one (except
-	if a `NULL` pointer was passed).
-
 `OPT_NUMBER_CALLBACK(&var, description, func_ptr)`::
 	Recognize numerical options like -123 and feed the integer as
 	if it was an argument to the function given by `func_ptr`.
diff --git a/Documentation/technical/api-trace2.txt b/Documentation/technical/api-trace2.txt
index 037a91c..ef7fe02 100644
--- a/Documentation/technical/api-trace2.txt
+++ b/Documentation/technical/api-trace2.txt
@@ -493,6 +493,20 @@
 }
 ------------
 
+`"cmd_ancestry"`::
+	This event contains the text command name for the parent (and earlier
+	generations of parents) of the current process, in an array ordered from
+	nearest parent to furthest great-grandparent. It may not be implemented
+	on all platforms.
++
+------------
+{
+	"event":"cmd_ancestry",
+	...
+	"ancestry":["bash","tmux: server","systemd"]
+}
+------------
+
 `"cmd_name"`::
 	This event contains the command name for this git process
 	and the hierarchy of commands from parent git processes.
@@ -599,6 +613,46 @@
 So this time will be slightly larger than the atexit time reported by
 the child process itself.
 
+`"child_ready"`::
+	This event is generated after the current process has started
+	a background process and released all handles to it.
++
+------------
+{
+	"event":"child_ready",
+	...
+	"child_id":2,
+	"pid":14708,	 # child PID
+	"ready":"ready", # child ready state
+	"t_rel":0.110605 # observed run-time of child process
+}
+------------
++
+Note that the session-id of the child process is not available to
+the current/spawning process, so the child's PID is reported here as
+a hint for post-processing.  (But it is only a hint because the child
+process may be a shell script which doesn't have a session-id.)
++
+This event is generated after the child is started in the background
+and given a little time to boot up and start working.  If the child
+startups normally and while the parent is still waiting, the "ready"
+field will have the value "ready".
+If the child is too slow to start and the parent times out, the field
+will have the value "timeout".
+If the child starts but the parent is unable to probe it, the field
+will have the value "error".
++
+After the parent process emits this event, it will release all of its
+handles to the child process and treat the child as a background
+daemon.  So even if the child does eventually finish booting up,
+the parent will not emit an updated event.
++
+Note that the `t_rel` field contains the observed run time in seconds
+when the parent released the child process into the background.
+The child is assumed to be a long-running daemon process and may
+outlive the parent process.  So the parent's child event times should
+not be compared to the child's atexit times.
+
 `"exec"`::
 	This event is generated before git attempts to `exec()`
 	another command rather than starting a child process.
diff --git a/Documentation/technical/bitmap-format.txt b/Documentation/technical/bitmap-format.txt
index f8c18a0..04b3ec2 100644
--- a/Documentation/technical/bitmap-format.txt
+++ b/Documentation/technical/bitmap-format.txt
@@ -1,6 +1,44 @@
 GIT bitmap v1 format
 ====================
 
+== Pack and multi-pack bitmaps
+
+Bitmaps store reachability information about the set of objects in a packfile,
+or a multi-pack index (MIDX). The former is defined obviously, and the latter is
+defined as the union of objects in packs contained in the MIDX.
+
+A bitmap may belong to either one pack, or the repository's multi-pack index (if
+it exists). A repository may have at most one bitmap.
+
+An object is uniquely described by its bit position within a bitmap:
+
+	- If the bitmap belongs to a packfile, the __n__th bit corresponds to
+	the __n__th object in pack order. For a function `offset` which maps
+	objects to their byte offset within a pack, pack order is defined as
+	follows:
+
+		o1 <= o2 <==> offset(o1) <= offset(o2)
+
+	- If the bitmap belongs to a MIDX, the __n__th bit corresponds to the
+	__n__th object in MIDX order. With an additional function `pack` which
+	maps objects to the pack they were selected from by the MIDX, MIDX order
+	is defined as follows:
+
+		o1 <= o2 <==> pack(o1) <= pack(o2) /\ offset(o1) <= offset(o2)
+
+	The ordering between packs is done according to the MIDX's .rev file.
+	Notably, the preferred pack sorts ahead of all other packs.
+
+The on-disk representation (described below) of a bitmap is the same regardless
+of whether or not that bitmap belongs to a packfile or a MIDX. The only
+difference is the interpretation of the bits, which is described above.
+
+Certain bitmap extensions are supported (see: Appendix B). No extensions are
+required for bitmaps corresponding to packfiles. For bitmaps that correspond to
+MIDXs, both the bit-cache and rev-cache extensions are required.
+
+== On-disk format
+
 	- A header appears at the beginning:
 
 		4-byte signature: {'B', 'I', 'T', 'M'}
@@ -14,17 +52,19 @@
 			The following flags are supported:
 
 			- BITMAP_OPT_FULL_DAG (0x1) REQUIRED
-			This flag must always be present. It implies that the bitmap
-			index has been generated for a packfile with full closure
-			(i.e. where every single object in the packfile can find
-			 its parent links inside the same packfile). This is a
-			requirement for the bitmap index format, also present in JGit,
-			that greatly reduces the complexity of the implementation.
+			This flag must always be present. It implies that the
+			bitmap index has been generated for a packfile or
+			multi-pack index (MIDX) with full closure (i.e. where
+			every single object in the packfile/MIDX can find its
+			parent links inside the same packfile/MIDX). This is a
+			requirement for the bitmap index format, also present in
+			JGit, that greatly reduces the complexity of the
+			implementation.
 
 			- BITMAP_OPT_HASH_CACHE (0x4)
 			If present, the end of the bitmap file contains
 			`N` 32-bit name-hash values, one per object in the
-			pack. The format and meaning of the name-hash is
+			pack/MIDX. The format and meaning of the name-hash is
 			described below.
 
 		4-byte entry count (network byte order)
@@ -33,7 +73,8 @@
 
 		20-byte checksum
 
-			The SHA1 checksum of the pack this bitmap index belongs to.
+			The SHA1 checksum of the pack/MIDX this bitmap index
+			belongs to.
 
 	- 4 EWAH bitmaps that act as type indexes
 
@@ -50,7 +91,7 @@
 			- Tags
 
 		In each bitmap, the `n`th bit is set to true if the `n`th object
-		in the packfile is of that type.
+		in the packfile or multi-pack index is of that type.
 
 		The obvious consequence is that the OR of all 4 bitmaps will result
 		in a full set (all bits set), and the AND of all 4 bitmaps will
@@ -62,8 +103,9 @@
 		Each entry contains the following:
 
 		- 4-byte object position (network byte order)
-			The position **in the index for the packfile** where the
-			bitmap for this commit is found.
+			The position **in the index for the packfile or
+			multi-pack index** where the bitmap for this commit is
+			found.
 
 		- 1-byte XOR-offset
 			The xor offset used to compress this bitmap. For an entry
@@ -146,10 +188,11 @@
 ---------------
 
 If the BITMAP_OPT_HASH_CACHE flag is set, the end of the bitmap contains
-a cache of 32-bit values, one per object in the pack. The value at
+a cache of 32-bit values, one per object in the pack/MIDX. The value at
 position `i` is the hash of the pathname at which the `i`th object
-(counting in index order) in the pack can be found.  This can be fed
-into the delta heuristics to compare objects with similar pathnames.
+(counting in index or multi-pack index order) in the pack/MIDX can be found.
+This can be fed into the delta heuristics to compare objects with similar
+pathnames.
 
 The hash algorithm used is:
 
diff --git a/Documentation/technical/http-protocol.txt b/Documentation/technical/http-protocol.txt
index 96d89ea..cc5126c 100644
--- a/Documentation/technical/http-protocol.txt
+++ b/Documentation/technical/http-protocol.txt
@@ -225,6 +225,9 @@
 Documentation/technical/pack-protocol.txt) as a colon-separated string
 in the Git-Protocol HTTP header.
 
+Uses the `--http-backend-info-refs` option to
+linkgit:git-upload-pack[1].
+
 Dumb Server Response
 ^^^^^^^^^^^^^^^^^^^^
 Dumb servers MUST respond with the dumb server reply format.
diff --git a/Documentation/technical/multi-pack-index.txt b/Documentation/technical/multi-pack-index.txt
index fb68897..86f40f2 100644
--- a/Documentation/technical/multi-pack-index.txt
+++ b/Documentation/technical/multi-pack-index.txt
@@ -36,7 +36,9 @@
   directory of an alternate. It refers only to packfiles in that
   same directory.
 
-- The core.multiPackIndex config setting must be on to consume MIDX files.
+- The core.multiPackIndex config setting must be on (which is the
+  default) to consume MIDX files.  Setting it to `false` prevents
+  Git from reading a MIDX file, even if one exists.
 
 - The file format includes parameters for the object ID hash
   function, so a future change of hash algorithm does not require
@@ -71,14 +73,10 @@
   still reducing the number of binary searches required for object
   lookups.
 
-- The reachability bitmap is currently paired directly with a single
-  packfile, using the pack-order as the object order to hopefully
-  compress the bitmaps well using run-length encoding. This could be
-  extended to pair a reachability bitmap with a multi-pack-index. If
-  the multi-pack-index is extended to store a "stable object order"
+- If the multi-pack-index is extended to store a "stable object order"
   (a function Order(hash) = integer that is constant for a given hash,
-  even as the multi-pack-index is updated) then a reachability bitmap
-  could point to a multi-pack-index and be updated independently.
+  even as the multi-pack-index is updated) then MIDX bitmaps could be
+  updated independently of the MIDX.
 
 - Packfiles can be marked as "special" using empty files that share
   the initial name but replace ".pack" with ".keep" or ".promisor".
diff --git a/Documentation/technical/protocol-v2.txt b/Documentation/technical/protocol-v2.txt
index 1040d85..21e8258 100644
--- a/Documentation/technical/protocol-v2.txt
+++ b/Documentation/technical/protocol-v2.txt
@@ -42,7 +42,8 @@
 In general a client can request to speak protocol v2 by sending
 `version=2` through the respective side-channel for the transport being
 used which inevitably sets `GIT_PROTOCOL`.  More information can be
-found in `pack-protocol.txt` and `http-protocol.txt`.  In all cases the
+found in `pack-protocol.txt` and `http-protocol.txt`, as well as the
+`GIT_PROTOCOL` definition in `git.txt`. In all cases the
 response from the server is the capability advertisement.
 
 Git Transport
@@ -58,6 +59,8 @@
 
 When using either the ssh:// or file:// transport, the GIT_PROTOCOL
 environment variable must be set explicitly to include "version=2".
+The server may need to be configured to allow this environment variable
+to pass.
 
 HTTP Transport
 ~~~~~~~~~~~~~~
@@ -81,6 +84,12 @@
 Subsequent requests are then made directly to the service
 `$GIT_URL/git-upload-pack`. (This works the same for git-receive-pack).
 
+Uses the `--http-backend-info-refs` option to
+linkgit:git-upload-pack[1].
+
+The server may need to be configured to pass this header's contents via
+the `GIT_PROTOCOL` variable. See the discussion in `git-http-backend.txt`.
+
 Capability Advertisement
 ------------------------
 
@@ -190,7 +199,11 @@
 	Show peeled tags.
     ref-prefix <prefix>
 	When specified, only references having a prefix matching one of
-	the provided prefixes are displayed.
+	the provided prefixes are displayed. Multiple instances may be
+	given, in which case references matching any prefix will be
+	shown. Note that this is purely for optimization; a server MAY
+	show refs not matching the prefix if it chooses, and clients
+	should filter the result themselves.
 
 If the 'unborn' feature is advertised the following argument can be
 included in the client's request.
diff --git a/Documentation/technical/signature-format.txt b/Documentation/technical/signature-format.txt
index 2c9406a..166721b 100644
--- a/Documentation/technical/signature-format.txt
+++ b/Documentation/technical/signature-format.txt
@@ -13,6 +13,22 @@
 and end with `-----END PGP SIGNATURE-----`, unless gpg is told to
 produce RFC1991 signatures which use `MESSAGE` instead of `SIGNATURE`.
 
+Signatures sometimes appear as a part of the normal payload
+(e.g. a signed tag has the signature block appended after the payload
+that the signature applies to), and sometimes appear in the value of
+an object header (e.g. a merge commit that merged a signed tag would
+have the entire tag contents on its "mergetag" header).  In the case
+of the latter, the usual multi-line formatting rule for object
+headers applies.  I.e. the second and subsequent lines are prefixed
+with a SP to signal that the line is continued from the previous
+line.
+
+This is even true for an originally empty line.  In the following
+examples, the end of line that ends with a whitespace letter is
+highlighted with a `$` sign; if you are trying to recreate these
+example by hand, do not cut and paste them---they are there
+primarily to highlight extra whitespace at the end of some lines.
+
 The signed payload and the way the signature is embedded depends
 on the type of the object resp. transaction.
 
@@ -78,7 +94,7 @@
 committer C O Mitter <committer@example.com> 1465981137 +0000
 gpgsig -----BEGIN PGP SIGNATURE-----
  Version: GnuPG v1
-
+ $
  iQEcBAABAgAGBQJXYRjRAAoJEGEJLoW3InGJ3IwIAIY4SA6GxY3BjL60YyvsJPh/
  HRCJwH+w7wt3Yc/9/bW2F+gF72kdHOOs2jfv+OZhq0q4OAN6fvVSczISY/82LpS7
  DVdMQj2/YcHDT4xrDNBnXnviDO9G7am/9OE77kEbXrp7QPxvhjkicHNwy2rEflAA
@@ -128,13 +144,13 @@
  type commit
  tag signedtag
  tagger C O Mitter <committer@example.com> 1465981006 +0000
-
+ $
  signed tag
-
+ $
  signed tag message body
  -----BEGIN PGP SIGNATURE-----
  Version: GnuPG v1
-
+ $
  iQEcBAABAgAGBQJXYRhOAAoJEGEJLoW3InGJklkIAIcnhL7RwEb/+QeX9enkXhxn
  rxfdqrvWd1K80sl2TOt8Bg/NYwrUBw/RWJ+sg/hhHp4WtvE1HDGHlkEz3y11Lkuh
  8tSxS3qKTxXUGozyPGuE90sJfExhZlW4knIQ1wt/yWqM+33E9pN4hzPqLwyrdods
diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt
index 9624059..865074b 100644
--- a/Documentation/user-manual.txt
+++ b/Documentation/user-manual.txt
@@ -3190,7 +3190,7 @@
 not being pointed to by any commit or tree, so it's now a dangling blob
 object.
 
-Similarly, when the "recursive" merge strategy runs, and finds that
+Similarly, when the "ort" merge strategy runs, and finds that
 there are criss-cross merges and thus more than one merge base (which is
 fairly unusual, but it does happen), it will generate one temporary
 midway tree (or possibly even more, if you had lots of criss-crossing
diff --git a/GIT-VERSION-GEN b/GIT-VERSION-GEN
index b1c0d4e..b48559d 100755
--- a/GIT-VERSION-GEN
+++ b/GIT-VERSION-GEN
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 GVF=GIT-VERSION-FILE
-DEF_VER=v2.33.0
+DEF_VER=v2.33.GIT
 
 LF='
 '
diff --git a/INSTALL b/INSTALL
index 66389ce..4140a3f 100644
--- a/INSTALL
+++ b/INSTALL
@@ -138,12 +138,15 @@
 	  BLK_SHA1.  Also included is a version optimized for PowerPC
 	  (PPC_SHA1).
 
-	- "libcurl" library is used by git-http-fetch, git-fetch, and, if
-	  the curl version >= 7.34.0, for git-imap-send.  You might also
-	  want the "curl" executable for debugging purposes. If you do not
-	  use http:// or https:// repositories, and do not want to put
-	  patches into an IMAP mailbox, you do not have to have them
-	  (use NO_CURL).
+	- "libcurl" library is used for fetching and pushing
+	  repositories over http:// or https://, as well as by
+	  git-imap-send if the curl version is >= 7.34.0. If you do
+	  not need that functionality, use NO_CURL to build without
+	  it.
+
+	  Git requires version "7.19.4" or later of "libcurl" to build
+	  without NO_CURL. This version requirement may be bumped in
+	  the future.
 
 	- "expat" library; git-http-push uses it for remote lock
 	  management over DAV.  Similar to "curl" above, this is optional
diff --git a/Makefile b/Makefile
index 3df0ab5..12be39a 100644
--- a/Makefile
+++ b/Makefile
@@ -409,15 +409,6 @@
 # Define NEEDS_LIBRT if your platform requires linking with librt (glibc version
 # before 2.17) for clock_gettime and CLOCK_MONOTONIC.
 #
-# Define USE_PARENS_AROUND_GETTEXT_N to "yes" if your compiler happily
-# compiles the following initialization:
-#
-#   static const char s[] = ("FOO");
-#
-# and define it to "no" if you need to remove the parentheses () around the
-# constant.  The default is "auto", which means to use parentheses if your
-# compiler is detected to support it.
-#
 # Define HAVE_BSD_SYSCTL if your platform has a BSD-compatible sysctl function.
 #
 # Define HAVE_GETDELIM if your system has the getdelim() function.
@@ -465,6 +456,9 @@
 # the global variable _wpgmptr containing the absolute path of the current
 # executable (this is the case on Windows).
 #
+# INSTALL_STRIP can be set to "-s" to strip binaries during installation,
+# if your $(INSTALL) command supports the option.
+#
 # Define GENERATE_COMPILATION_DATABASE to "yes" to generate JSON compilation
 # database entries during compilation if your compiler supports it, using the
 # `-MJ` flag. The JSON entries will be placed in the `compile_commands/`
@@ -495,10 +489,9 @@
 #        setting this flag the exceptions are removed, and all of
 #        -Wextra is used.
 #
-#    pedantic:
+#    no-pedantic:
 #
-#        Enable -pedantic compilation. This also disables
-#        USE_PARENS_AROUND_GETTEXT_N to produce only relevant warnings.
+#        Disable -pedantic compilation.
 
 GIT-VERSION-FILE: FORCE
 	@$(SHELL_PATH) ./GIT-VERSION-GEN
@@ -616,7 +609,6 @@
 SCRIPT_SH += git-web--browse.sh
 
 SCRIPT_LIB += git-mergetool--lib
-SCRIPT_LIB += git-rebase--preserve-merges
 SCRIPT_LIB += git-sh-i18n
 SCRIPT_LIB += git-sh-setup
 
@@ -824,6 +816,10 @@
 
 GENERATED_H += command-list.h
 GENERATED_H += config-list.h
+GENERATED_H += hook-list.h
+
+.PHONY: generated-hdrs
+generated-hdrs: $(GENERATED_H)
 
 LIB_H := $(sort $(patsubst ./%,%,$(shell git ls-files '*.h' ':!t/' ':!Documentation/' 2>/dev/null || \
 	$(FIND) . \
@@ -909,6 +905,7 @@
 LIB_OBJS += hashmap.o
 LIB_OBJS += help.o
 LIB_OBJS += hex.o
+LIB_OBJS += hook.o
 LIB_OBJS += ident.o
 LIB_OBJS += json-writer.o
 LIB_OBJS += kwset.o
@@ -1221,6 +1218,9 @@
 SPARSE_FLAGS ?=
 SP_EXTRA_FLAGS = -Wno-universal-initializer
 
+# For informing GIT-BUILD-OPTIONS of the SANITIZE=leak target
+SANITIZE_LEAK =
+
 # 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.
@@ -1265,6 +1265,7 @@
 endif
 ifneq ($(filter leak,$(SANITIZERS)),)
 BASIC_CFLAGS += -DSUPPRESS_ANNOTATED_LEAKS
+SANITIZE_LEAK = YesCompiledWithIt
 endif
 ifneq ($(filter address,$(SANITIZERS)),)
 NO_REGEX = NeededForASAN
@@ -1285,6 +1286,7 @@
 
 ifeq ($(COMPUTE_HEADER_DEPENDENCIES),auto)
 dep_check = $(shell $(CC) $(ALL_CFLAGS) \
+	-Wno-pedantic \
 	-c -MF /dev/null -MQ /dev/null -MMD -MP \
 	-x c /dev/null -o /dev/null 2>&1; \
 	echo $$?)
@@ -1310,6 +1312,7 @@
 
 ifeq ($(GENERATE_COMPILATION_DATABASE),yes)
 compdb_check = $(shell $(CC) $(ALL_CFLAGS) \
+	-Wno-pedantic \
 	-c -MJ /dev/null \
 	-x c /dev/null -o /dev/null 2>&1; \
 	echo $$?)
@@ -1347,14 +1350,6 @@
 	BASIC_CFLAGS += -Dsocklen_t=$(SOCKLEN_T)
 endif
 
-ifeq (yes,$(USE_PARENS_AROUND_GETTEXT_N))
-	BASIC_CFLAGS += -DUSE_PARENS_AROUND_GETTEXT_N=1
-else
-ifeq (no,$(USE_PARENS_AROUND_GETTEXT_N))
-	BASIC_CFLAGS += -DUSE_PARENS_AROUND_GETTEXT_N=0
-endif
-endif
-
 ifeq ($(uname_S),Darwin)
 	ifndef NO_FINK
 		ifeq ($(shell test -d /sw/lib && echo y),y)
@@ -1436,15 +1431,8 @@
 	REMOTE_CURL_NAMES = $(REMOTE_CURL_PRIMARY) $(REMOTE_CURL_ALIASES)
 	PROGRAM_OBJS += http-fetch.o
 	PROGRAMS += $(REMOTE_CURL_NAMES)
-	curl_check := $(shell (echo 070908; $(CURL_CONFIG) --vernum | sed -e '/^70[BC]/s/^/0/') 2>/dev/null | sort -r | sed -ne 2p)
-	ifeq "$(curl_check)" "070908"
-		ifndef NO_EXPAT
-			PROGRAM_OBJS += http-push.o
-		else
-			EXCLUDED_PROGRAMS += git-http-push
-		endif
-	else
-		EXCLUDED_PROGRAMS += git-http-push
+	ifndef NO_EXPAT
+		PROGRAM_OBJS += http-push.o
 	endif
 	curl_check := $(shell (echo 072200; $(CURL_CONFIG) --vernum | sed -e '/^70[BC]/s/^/0/') 2>/dev/null | sort -r | sed -ne 2p)
 	ifeq "$(curl_check)" "072200"
@@ -1917,6 +1905,10 @@
 	BASIC_CFLAGS += '-DPROCFS_EXECUTABLE_PATH="$(procfs_executable_path_SQ)"'
 endif
 
+ifndef HAVE_PLATFORM_PROCINFO
+	COMPAT_OBJS += compat/stub/procinfo.o
+endif
+
 ifdef HAVE_NS_GET_EXECUTABLE_PATH
 	BASIC_CFLAGS += -DHAVE_NS_GET_EXECUTABLE_PATH
 endif
@@ -2223,8 +2215,9 @@
 		$(filter %.o,$^) $(LIBS)
 
 help.sp help.s help.o: command-list.h
+hook.sp hook.s hook.o: hook-list.h
 
-builtin/help.sp builtin/help.s builtin/help.o: config-list.h GIT-PREFIX
+builtin/help.sp builtin/help.s builtin/help.o: config-list.h hook-list.h GIT-PREFIX
 builtin/help.sp builtin/help.s builtin/help.o: EXTRA_CPPFLAGS = \
 	'-DGIT_HTML_PATH="$(htmldir_relative_SQ)"' \
 	'-DGIT_MAN_PATH="$(mandir_relative_SQ)"' \
@@ -2247,15 +2240,17 @@
 config-list.h: generate-configlist.sh
 
 config-list.h: Documentation/*config.txt Documentation/config/*.txt
-	$(QUIET_GEN)$(SHELL_PATH) ./generate-configlist.sh \
-		>$@+ && mv $@+ $@
+	$(QUIET_GEN)$(SHELL_PATH) ./generate-configlist.sh >$@
 
 command-list.h: generate-cmdlist.sh command-list.txt
 
 command-list.h: $(wildcard Documentation/git*.txt)
 	$(QUIET_GEN)$(SHELL_PATH) ./generate-cmdlist.sh \
 		$(patsubst %,--exclude-program %,$(EXCLUDED_PROGRAMS)) \
-		command-list.txt >$@+ && mv $@+ $@
+		command-list.txt >$@
+
+hook-list.h: generate-hooklist.sh Documentation/githooks.txt
+	$(QUIET_GEN)$(SHELL_PATH) ./generate-hooklist.sh >$@
 
 SCRIPT_DEFINES = $(SHELL_PATH_SQ):$(DIFF_SQ):$(GIT_VERSION):\
 	$(localedir_SQ):$(NO_CURL):$(USE_GETTEXT_SCHEME):$(SANE_TOOL_PATH_SQ):\
@@ -2517,13 +2512,6 @@
 include $(dep_files_present)
 endif
 else
-# Dependencies on header files, for platforms that do not support
-# the gcc -MMD option.
-#
-# Dependencies on automatically generated headers such as command-list.h
-# should _not_ be included here, since they are necessary even when
-# building an object for the first time.
-
 $(OBJECTS): $(LIB_H) $(GENERATED_H)
 endif
 
@@ -2648,7 +2636,6 @@
 	--keyword=__ --keyword=N__ --keyword="__n:1,2"
 LOCALIZED_C = $(C_OBJ:o=c) $(LIB_H) $(GENERATED_H)
 LOCALIZED_SH = $(SCRIPT_SH)
-LOCALIZED_SH += git-rebase--preserve-merges.sh
 LOCALIZED_SH += git-sh-setup.sh
 LOCALIZED_PERL = $(SCRIPT_PERL)
 
@@ -2745,19 +2732,25 @@
 		| sed -e 's|^\./||' \
 	)
 
-$(ETAGS_TARGET): FORCE
-	$(QUIET_GEN)$(RM) "$(ETAGS_TARGET)+" && \
-	$(FIND_SOURCE_FILES) | xargs etags -a -o "$(ETAGS_TARGET)+" && \
-	mv "$(ETAGS_TARGET)+" "$(ETAGS_TARGET)"
+FOUND_SOURCE_FILES = $(shell $(FIND_SOURCE_FILES))
 
-tags: FORCE
-	$(QUIET_GEN)$(RM) tags+ && \
-	$(FIND_SOURCE_FILES) | xargs ctags -a -o tags+ && \
-	mv tags+ tags
+$(ETAGS_TARGET): $(FOUND_SOURCE_FILES)
+	$(QUIET_GEN)$(RM) $@+ && \
+	echo $(FOUND_SOURCE_FILES) | xargs etags -a -o $@+ && \
+	mv $@+ $@
 
-cscope:
-	$(RM) cscope*
-	$(FIND_SOURCE_FILES) | xargs cscope -b
+tags: $(FOUND_SOURCE_FILES)
+	$(QUIET_GEN)$(RM) $@+ && \
+	echo $(FOUND_SOURCE_FILES) | xargs ctags -a -o $@+ && \
+	mv $@+ $@
+
+cscope.out: $(FOUND_SOURCE_FILES)
+	$(QUIET_GEN)$(RM) $@+ && \
+	echo $(FOUND_SOURCE_FILES) | xargs cscope -f$@+ -b && \
+	mv $@+ $@
+
+.PHONY: cscope
+cscope: cscope.out
 
 ### Detect prefix changes
 TRACK_PREFIX = $(bindir_SQ):$(gitexecdir_SQ):$(template_dir_SQ):$(prefix_SQ):\
@@ -2807,6 +2800,7 @@
 	@echo NO_UNIX_SOCKETS=\''$(subst ','\'',$(subst ','\'',$(NO_UNIX_SOCKETS)))'\' >>$@+
 	@echo PAGER_ENV=\''$(subst ','\'',$(subst ','\'',$(PAGER_ENV)))'\' >>$@+
 	@echo DC_SHA1=\''$(subst ','\'',$(subst ','\'',$(DC_SHA1)))'\' >>$@+
+	@echo SANITIZE_LEAK=\''$(subst ','\'',$(subst ','\'',$(SANITIZE_LEAK)))'\' >>$@+
 	@echo X=\'$(X)\' >>$@+
 ifdef TEST_OUTPUT_DIRECTORY
 	@echo TEST_OUTPUT_DIRECTORY=\''$(subst ','\'',$(subst ','\'',$(TEST_OUTPUT_DIRECTORY)))'\' >>$@+
@@ -2848,6 +2842,11 @@
 ifdef GIT_TEST_PERL_FATAL_WARNINGS
 	@echo GIT_TEST_PERL_FATAL_WARNINGS=\''$(subst ','\'',$(subst ','\'',$(GIT_TEST_PERL_FATAL_WARNINGS)))'\' >>$@+
 endif
+ifdef RUNTIME_PREFIX
+	@echo RUNTIME_PREFIX=\'true\' >>$@+
+else
+	@echo RUNTIME_PREFIX=\'false\' >>$@+
+endif
 	@if cmp $@+ $@ >/dev/null 2>&1; then $(RM) $@+; else mv $@+ $@; fi
 
 ### Detect Python interpreter path changes
@@ -2902,14 +2901,16 @@
 
 SP_OBJ = $(patsubst %.o,%.sp,$(C_OBJ))
 
-$(SP_OBJ): %.sp: %.c GIT-CFLAGS FORCE
+$(SP_OBJ): %.sp: %.c %.o
 	$(QUIET_SP)cgcc -no-compile $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) \
-		$(SPARSE_FLAGS) $(SP_EXTRA_FLAGS) $<
+		-Wsparse-error \
+		$(SPARSE_FLAGS) $(SP_EXTRA_FLAGS) $< && \
+	>$@
 
-.PHONY: sparse $(SP_OBJ)
+.PHONY: sparse
 sparse: $(SP_OBJ)
 
-EXCEPT_HDRS := command-list.h config-list.h unicode-width.h compat/% xdiff/%
+EXCEPT_HDRS := $(GENERATED_H) unicode-width.h compat/% xdiff/%
 ifndef GCRYPT_SHA256
 	EXCEPT_HDRS += sha256/gcrypt.h
 endif
@@ -2931,7 +2932,8 @@
 style:
 	git clang-format --style file --diff --extensions c,h
 
-check: config-list.h command-list.h
+.PHONY: check
+check: $(GENERATED_H)
 	@if sparse; \
 	then \
 		echo >&2 "Use 'make sparse' instead"; \
@@ -2941,7 +2943,7 @@
 		exit 1; \
 	fi
 
-FOUND_C_SOURCES = $(filter %.c,$(shell $(FIND_SOURCE_FILES)))
+FOUND_C_SOURCES = $(filter %.c,$(FOUND_SOURCE_FILES))
 COCCI_SOURCES = $(filter-out $(THIRD_PARTY_SOURCES),$(FOUND_C_SOURCES))
 
 %.cocci.patch: %.cocci $(COCCI_SOURCES)
@@ -2994,7 +2996,8 @@
 endif
 mergetools_instdir_SQ = $(subst ','\'',$(mergetools_instdir))
 
-install_bindir_programs := $(patsubst %,%$X,$(BINDIR_PROGRAMS_NEED_X)) $(BINDIR_PROGRAMS_NO_X)
+install_bindir_xprograms := $(patsubst %,%$X,$(BINDIR_PROGRAMS_NEED_X))
+install_bindir_programs := $(install_bindir_xprograms) $(BINDIR_PROGRAMS_NO_X)
 
 .PHONY: profile-install profile-fast-install
 profile-install: profile
@@ -3003,12 +3006,17 @@
 profile-fast-install: profile-fast
 	$(MAKE) install
 
+INSTALL_STRIP =
+
 install: all
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(bindir_SQ)'
 	$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(gitexec_instdir_SQ)'
-	$(INSTALL) $(ALL_PROGRAMS) '$(DESTDIR_SQ)$(gitexec_instdir_SQ)'
+	$(INSTALL) $(INSTALL_STRIP) $(PROGRAMS) '$(DESTDIR_SQ)$(gitexec_instdir_SQ)'
+	$(INSTALL) $(SCRIPTS) '$(DESTDIR_SQ)$(gitexec_instdir_SQ)'
 	$(INSTALL) -m 644 $(SCRIPT_LIB) '$(DESTDIR_SQ)$(gitexec_instdir_SQ)'
-	$(INSTALL) $(install_bindir_programs) '$(DESTDIR_SQ)$(bindir_SQ)'
+	$(INSTALL) $(INSTALL_STRIP) $(install_bindir_xprograms) '$(DESTDIR_SQ)$(bindir_SQ)'
+	$(INSTALL) $(BINDIR_PROGRAMS_NO_X) '$(DESTDIR_SQ)$(bindir_SQ)'
+
 ifdef MSVC
 	# We DO NOT install the individual foo.o.pdb files because they
 	# have already been rolled up into the exe's pdb file.
@@ -3227,6 +3235,7 @@
 	$(RM) $(ALL_PROGRAMS) $(SCRIPT_LIB) $(BUILT_INS) git$X
 	$(RM) $(TEST_PROGRAMS)
 	$(RM) $(FUZZ_PROGRAMS)
+	$(RM) $(SP_OBJ)
 	$(RM) $(HCC)
 	$(RM) -r bin-wrappers $(dep_dirs) $(compdb_dir) compile_commands.json
 	$(RM) -r po/build/
@@ -3265,7 +3274,7 @@
 
 .PHONY: all install profile-clean cocciclean clean strip
 .PHONY: shell_compatibility_test please_set_SHELL_PATH_to_a_more_modern_shell
-.PHONY: FORCE cscope
+.PHONY: FORCE
 
 ### Check documentation
 #
diff --git a/RelNotes b/RelNotes
index 567659e..6c94469 120000
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes/2.33.1.txt
\ No newline at end of file
+Documentation/RelNotes/2.34.0.txt
\ No newline at end of file
diff --git a/add-interactive.c b/add-interactive.c
index 36ebdbd..6498ae1 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -102,8 +102,12 @@
 	int *selected; /* for multi-selections */
 	size_t min_length, max_length;
 };
-#define PREFIX_ITEM_LIST_INIT \
-	{ STRING_LIST_INIT_DUP, STRING_LIST_INIT_NODUP, NULL, 1, 4 }
+#define PREFIX_ITEM_LIST_INIT { \
+	.items = STRING_LIST_INIT_DUP, \
+	.sorted = STRING_LIST_INIT_NODUP, \
+	.min_length = 1, \
+	.max_length = 4, \
+}
 
 static void prefix_item_list_clear(struct prefix_item_list *list)
 {
diff --git a/advice.c b/advice.c
index 337e8f3..1dfc91d 100644
--- a/advice.c
+++ b/advice.c
@@ -4,37 +4,6 @@
 #include "help.h"
 #include "string-list.h"
 
-int advice_fetch_show_forced_updates = 1;
-int advice_push_update_rejected = 1;
-int advice_push_non_ff_current = 1;
-int advice_push_non_ff_matching = 1;
-int advice_push_already_exists = 1;
-int advice_push_fetch_first = 1;
-int advice_push_needs_force = 1;
-int advice_push_unqualified_ref_name = 1;
-int advice_push_ref_needs_update = 1;
-int advice_status_hints = 1;
-int advice_status_u_option = 1;
-int advice_status_ahead_behind_warning = 1;
-int advice_commit_before_merge = 1;
-int advice_reset_quiet_warning = 1;
-int advice_resolve_conflict = 1;
-int advice_sequencer_in_use = 1;
-int advice_implicit_identity = 1;
-int advice_detached_head = 1;
-int advice_set_upstream_failure = 1;
-int advice_object_name_warning = 1;
-int advice_amworkdir = 1;
-int advice_rm_hints = 1;
-int advice_add_embedded_repo = 1;
-int advice_ignored_hook = 1;
-int advice_waiting_for_editor = 1;
-int advice_graft_file_deprecated = 1;
-int advice_checkout_ambiguous_remote_branch_name = 1;
-int advice_submodule_alternate_error_strategy_die = 1;
-int advice_add_ignored_file = 1;
-int advice_add_empty_pathspec = 1;
-
 static int advice_use_color = -1;
 static char advice_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_RESET,
@@ -63,49 +32,12 @@
 }
 
 static struct {
-	const char *name;
-	int *preference;
-} advice_config[] = {
-	{ "fetchShowForcedUpdates", &advice_fetch_show_forced_updates },
-	{ "pushUpdateRejected", &advice_push_update_rejected },
-	{ "pushNonFFCurrent", &advice_push_non_ff_current },
-	{ "pushNonFFMatching", &advice_push_non_ff_matching },
-	{ "pushAlreadyExists", &advice_push_already_exists },
-	{ "pushFetchFirst", &advice_push_fetch_first },
-	{ "pushNeedsForce", &advice_push_needs_force },
-	{ "pushUnqualifiedRefName", &advice_push_unqualified_ref_name },
-	{ "pushRefNeedsUpdate", &advice_push_ref_needs_update },
-	{ "statusHints", &advice_status_hints },
-	{ "statusUoption", &advice_status_u_option },
-	{ "statusAheadBehindWarning", &advice_status_ahead_behind_warning },
-	{ "commitBeforeMerge", &advice_commit_before_merge },
-	{ "resetQuiet", &advice_reset_quiet_warning },
-	{ "resolveConflict", &advice_resolve_conflict },
-	{ "sequencerInUse", &advice_sequencer_in_use },
-	{ "implicitIdentity", &advice_implicit_identity },
-	{ "detachedHead", &advice_detached_head },
-	{ "setUpstreamFailure", &advice_set_upstream_failure },
-	{ "objectNameWarning", &advice_object_name_warning },
-	{ "amWorkDir", &advice_amworkdir },
-	{ "rmHints", &advice_rm_hints },
-	{ "addEmbeddedRepo", &advice_add_embedded_repo },
-	{ "ignoredHook", &advice_ignored_hook },
-	{ "waitingForEditor", &advice_waiting_for_editor },
-	{ "graftFileDeprecated", &advice_graft_file_deprecated },
-	{ "checkoutAmbiguousRemoteBranchName", &advice_checkout_ambiguous_remote_branch_name },
-	{ "submoduleAlternateErrorStrategyDie", &advice_submodule_alternate_error_strategy_die },
-	{ "addIgnoredFile", &advice_add_ignored_file },
-	{ "addEmptyPathspec", &advice_add_empty_pathspec },
-
-	/* make this an alias for backward compatibility */
-	{ "pushNonFastForward", &advice_push_update_rejected }
-};
-
-static struct {
 	const char *key;
 	int enabled;
 } advice_setting[] = {
 	[ADVICE_ADD_EMBEDDED_REPO]			= { "addEmbeddedRepo", 1 },
+	[ADVICE_ADD_EMPTY_PATHSPEC]			= { "addEmptyPathspec", 1 },
+	[ADVICE_ADD_IGNORED_FILE]			= { "addIgnoredFile", 1 },
 	[ADVICE_AM_WORK_DIR] 				= { "amWorkDir", 1 },
 	[ADVICE_CHECKOUT_AMBIGUOUS_REMOTE_BRANCH_NAME] 	= { "checkoutAmbiguousRemoteBranchName", 1 },
 	[ADVICE_COMMIT_BEFORE_MERGE]			= { "commitBeforeMerge", 1 },
@@ -133,6 +65,7 @@
 	[ADVICE_RM_HINTS]				= { "rmHints", 1 },
 	[ADVICE_SEQUENCER_IN_USE]			= { "sequencerInUse", 1 },
 	[ADVICE_SET_UPSTREAM_FAILURE]			= { "setUpstreamFailure", 1 },
+	[ADVICE_SKIPPED_CHERRY_PICKS]			= { "skippedCherryPicks", 1 },
 	[ADVICE_STATUS_AHEAD_BEHIND_WARNING]		= { "statusAheadBehindWarning", 1 },
 	[ADVICE_STATUS_HINTS]				= { "statusHints", 1 },
 	[ADVICE_STATUS_U_OPTION]			= { "statusUoption", 1 },
@@ -221,13 +154,6 @@
 	if (!skip_prefix(var, "advice.", &k))
 		return 0;
 
-	for (i = 0; i < ARRAY_SIZE(advice_config); i++) {
-		if (strcasecmp(k, advice_config[i].name))
-			continue;
-		*advice_config[i].preference = git_config_bool(var, value);
-		break;
-	}
-
 	for (i = 0; i < ARRAY_SIZE(advice_setting); i++) {
 		if (strcasecmp(k, advice_setting[i].key))
 			continue;
@@ -262,7 +188,7 @@
 		error(_("It is not possible to %s because you have unmerged files."),
 			me);
 
-	if (advice_resolve_conflict)
+	if (advice_enabled(ADVICE_RESOLVE_CONFLICT))
 		/*
 		 * Message used both when 'git commit' fails and when
 		 * other commands doing a merge do.
@@ -281,7 +207,7 @@
 void NORETURN die_conclude_merge(void)
 {
 	error(_("You have not concluded your merge (MERGE_HEAD exists)."));
-	if (advice_resolve_conflict)
+	if (advice_enabled(ADVICE_RESOLVE_CONFLICT))
 		advise(_("Please, commit your changes before merging."));
 	die(_("Exiting because of unfinished merge."));
 }
@@ -298,15 +224,16 @@
 	if (!pathspec_list->nr)
 		return;
 
-	fprintf(stderr, _("The following pathspecs didn't match any"
-			  " eligible path, but they do match index\n"
-			  "entries outside the current sparse checkout:\n"));
+	fprintf(stderr, _("The following paths and/or pathspecs matched paths that exist\n"
+			  "outside of your sparse-checkout definition, so will not be\n"
+			  "updated in the index:\n"));
 	for_each_string_list_item(item, pathspec_list)
 		fprintf(stderr, "%s\n", item->string);
 
 	advise_if_enabled(ADVICE_UPDATE_SPARSE_PATH,
-			  _("Disable or modify the sparsity rules if you intend"
-			    " to update such entries."));
+			  _("If you intend to update such entries, try one of the following:\n"
+			    "* Use the --sparse option.\n"
+			    "* Disable or modify the sparsity rules."));
 }
 
 void detach_advice(const char *new_name)
diff --git a/advice.h b/advice.h
index a7227ca..601265f 100644
--- a/advice.h
+++ b/advice.h
@@ -5,37 +5,6 @@
 
 struct string_list;
 
-extern int advice_fetch_show_forced_updates;
-extern int advice_push_update_rejected;
-extern int advice_push_non_ff_current;
-extern int advice_push_non_ff_matching;
-extern int advice_push_already_exists;
-extern int advice_push_fetch_first;
-extern int advice_push_needs_force;
-extern int advice_push_unqualified_ref_name;
-extern int advice_push_ref_needs_update;
-extern int advice_status_hints;
-extern int advice_status_u_option;
-extern int advice_status_ahead_behind_warning;
-extern int advice_commit_before_merge;
-extern int advice_reset_quiet_warning;
-extern int advice_resolve_conflict;
-extern int advice_sequencer_in_use;
-extern int advice_implicit_identity;
-extern int advice_detached_head;
-extern int advice_set_upstream_failure;
-extern int advice_object_name_warning;
-extern int advice_amworkdir;
-extern int advice_rm_hints;
-extern int advice_add_embedded_repo;
-extern int advice_ignored_hook;
-extern int advice_waiting_for_editor;
-extern int advice_graft_file_deprecated;
-extern int advice_checkout_ambiguous_remote_branch_name;
-extern int advice_submodule_alternate_error_strategy_die;
-extern int advice_add_ignored_file;
-extern int advice_add_empty_pathspec;
-
 /*
  * To add a new advice, you need to:
  * Define a new advice_type.
@@ -45,6 +14,8 @@
  */
  enum advice_type {
 	ADVICE_ADD_EMBEDDED_REPO,
+	ADVICE_ADD_EMPTY_PATHSPEC,
+	ADVICE_ADD_IGNORED_FILE,
 	ADVICE_AM_WORK_DIR,
 	ADVICE_CHECKOUT_AMBIGUOUS_REMOTE_BRANCH_NAME,
 	ADVICE_COMMIT_BEFORE_MERGE,
@@ -75,6 +46,7 @@
 	ADVICE_SUBMODULE_ALTERNATE_ERROR_STRATEGY_DIE,
 	ADVICE_UPDATE_SPARSE_PATH,
 	ADVICE_WAITING_FOR_EDITOR,
+	ADVICE_SKIPPED_CHERRY_PICKS,
 };
 
 int git_default_advice_config(const char *var, const char *value);
diff --git a/attr.c b/attr.c
index d029e68..79adaa5 100644
--- a/attr.c
+++ b/attr.c
@@ -14,6 +14,7 @@
 #include "utf8.h"
 #include "quote.h"
 #include "thread-utils.h"
+#include "dir.h"
 
 const char git_attr__true[] = "(builtin)true";
 const char git_attr__false[] = "\0(builtin)false";
@@ -744,6 +745,20 @@
 	if (!istate)
 		return NULL;
 
+	/*
+	 * The .gitattributes file only applies to files within its
+	 * parent directory. In the case of cone-mode sparse-checkout,
+	 * the .gitattributes file is sparse if and only if all paths
+	 * within that directory are also sparse. Thus, don't load the
+	 * .gitattributes file since it will not matter.
+	 *
+	 * In the case of a sparse index, it is critical that we don't go
+	 * looking for a .gitattributes file, as doing so would cause the
+	 * index to expand.
+	 */
+	if (!path_in_cone_mode_sparse_checkout(path, istate))
+		return NULL;
+
 	buf = read_blob_data_from_index(istate, path, NULL);
 	if (!buf)
 		return NULL;
diff --git a/bisect.c b/bisect.c
index af2863d..888949f 100644
--- a/bisect.c
+++ b/bisect.c
@@ -23,7 +23,6 @@
 static struct object_id *current_bad_oid;
 
 static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
-static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
 
 static const char *term_bad;
 static const char *term_good;
@@ -728,7 +727,9 @@
 static enum bisect_error bisect_checkout(const struct object_id *bisect_rev, int no_checkout)
 {
 	char bisect_rev_hex[GIT_MAX_HEXSZ + 1];
-	enum bisect_error res = BISECT_OK;
+	struct commit *commit;
+	struct pretty_print_context pp = {0};
+	struct strbuf commit_msg = STRBUF_INIT;
 
 	oid_to_hex_r(bisect_rev_hex, bisect_rev);
 	update_ref(NULL, "BISECT_EXPECTED_REV", bisect_rev, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
@@ -738,24 +739,21 @@
 		update_ref(NULL, "BISECT_HEAD", bisect_rev, NULL, 0,
 			   UPDATE_REFS_DIE_ON_ERR);
 	} else {
-		res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
-		if (res)
+		if (run_command_v_opt(argv_checkout, RUN_GIT_CMD))
 			/*
 			 * Errors in `run_command()` itself, signaled by res < 0,
 			 * and errors in the child process, signaled by res > 0
-			 * can both be treated as regular BISECT_FAILURE (-1).
+			 * can both be treated as regular BISECT_FAILED (-1).
 			 */
-			return -abs(res);
+			return BISECT_FAILED;
 	}
 
-	argv_show_branch[1] = bisect_rev_hex;
-	res = run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
-	/*
-	 * Errors in `run_command()` itself, signaled by res < 0,
-	 * and errors in the child process, signaled by res > 0
-	 * can both be treated as regular BISECT_FAILURE (-1).
-	 */
-	return -abs(res);
+	commit = lookup_commit_reference(the_repository, bisect_rev);
+	format_commit_message(commit, "[%H] %s%n", &commit_msg, &pp);
+	fputs(commit_msg.buf, stdout);
+	strbuf_release(&commit_msg);
+
+	return BISECT_OK;
 }
 
 static struct commit *get_commit_reference(struct repository *r,
diff --git a/branch.c b/branch.c
index 7a88a48..07a4643 100644
--- a/branch.c
+++ b/branch.c
@@ -271,7 +271,7 @@
 	real_ref = NULL;
 	if (get_oid_mb(start_name, &oid)) {
 		if (explicit_tracking) {
-			if (advice_set_upstream_failure) {
+			if (advice_enabled(ADVICE_SET_UPSTREAM_FAILURE)) {
 				error(_(upstream_missing), start_name);
 				advise(_(upstream_advice));
 				exit(1);
diff --git a/builtin.h b/builtin.h
index 16ecd55..8a58743 100644
--- a/builtin.h
+++ b/builtin.h
@@ -225,7 +225,6 @@
 int cmd_switch(int argc, const char **argv, const char *prefix);
 int cmd_symbolic_ref(int argc, const char **argv, const char *prefix);
 int cmd_tag(int argc, const char **argv, const char *prefix);
-int cmd_tar_tree(int argc, const char **argv, const char *prefix);
 int cmd_unpack_file(int argc, const char **argv, const char *prefix);
 int cmd_unpack_objects(int argc, const char **argv, const char *prefix);
 int cmd_update_index(int argc, const char **argv, const char *prefix);
diff --git a/builtin/add.c b/builtin/add.c
index c37c95b..ef6b619 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -30,6 +30,7 @@
 static int take_worktree_changes;
 static int add_renormalize;
 static int pathspec_file_nul;
+static int include_sparse;
 static const char *pathspec_from_file;
 static int legacy_stash_p; /* support for the scripted `git stash` */
 
@@ -46,7 +47,9 @@
 		struct cache_entry *ce = active_cache[i];
 		int err;
 
-		if (ce_skip_worktree(ce))
+		if (!include_sparse &&
+		    (ce_skip_worktree(ce) ||
+		     !path_in_sparse_checkout(ce->name, &the_index)))
 			continue;
 
 		if (pathspec && !ce_path_match(&the_index, ce, pathspec, NULL))
@@ -94,6 +97,10 @@
 	for (i = 0; i < q->nr; i++) {
 		struct diff_filepair *p = q->queue[i];
 		const char *path = p->one->path;
+
+		if (!include_sparse && !path_in_sparse_checkout(path, &the_index))
+			continue;
+
 		switch (fix_unmerged_status(p, data)) {
 		default:
 			die(_("unexpected diff status %c"), p->status);
@@ -144,12 +151,12 @@
 {
 	int i, retval = 0;
 
-	/* TODO: audit for interaction with sparse-index. */
-	ensure_full_index(&the_index);
 	for (i = 0; i < active_nr; i++) {
 		struct cache_entry *ce = active_cache[i];
 
-		if (ce_skip_worktree(ce))
+		if (!include_sparse &&
+		    (ce_skip_worktree(ce) ||
+		     !path_in_sparse_checkout(ce->name, &the_index)))
 			continue;
 		if (ce_stage(ce))
 			continue; /* do not touch unmerged paths */
@@ -198,7 +205,10 @@
 		      _("Unstaged changes after refreshing the index:"));
 	for (i = 0; i < pathspec->nr; i++) {
 		if (!seen[i]) {
-			if (matches_skip_worktree(pathspec, i, &skip_worktree_seen)) {
+			const char *path = pathspec->items[i].original;
+
+			if (matches_skip_worktree(pathspec, i, &skip_worktree_seen) ||
+			    !path_in_sparse_checkout(path, &the_index)) {
 				string_list_append(&only_match_skip_worktree,
 						   pathspec->items[i].original);
 			} else {
@@ -376,6 +386,7 @@
 	OPT_BOOL( 0 , "refresh", &refresh_only, N_("don't add, only refresh the index")),
 	OPT_BOOL( 0 , "ignore-errors", &ignore_add_errors, N_("just skip files which cannot be added because of errors")),
 	OPT_BOOL( 0 , "ignore-missing", &ignore_missing, N_("check if - even missing - files are ignored in dry run")),
+	OPT_BOOL(0, "sparse", &include_sparse, N_("allow updating entries outside of the sparse-checkout cone")),
 	OPT_STRING(0, "chmod", &chmod_arg, "(+|-)x",
 		   N_("override the executable bit of the listed files")),
 	OPT_HIDDEN_BOOL(0, "warn-embedded-repo", &warn_on_embedded_repo,
@@ -417,6 +428,7 @@
 static void check_embedded_repo(const char *path)
 {
 	struct strbuf name = STRBUF_INIT;
+	static int adviced_on_embedded_repo = 0;
 
 	if (!warn_on_embedded_repo)
 		return;
@@ -428,10 +440,10 @@
 	strbuf_strip_suffix(&name, "/");
 
 	warning(_("adding embedded git repository: %s"), name.buf);
-	if (advice_add_embedded_repo) {
+	if (!adviced_on_embedded_repo &&
+	    advice_enabled(ADVICE_ADD_EMBEDDED_REPO)) {
 		advise(embedded_advice, name.buf, name.buf);
-		/* there may be multiple entries; advise only once */
-		advice_add_embedded_repo = 0;
+		adviced_on_embedded_repo = 1;
 	}
 
 	strbuf_release(&name);
@@ -440,12 +452,13 @@
 static int add_files(struct dir_struct *dir, int flags)
 {
 	int i, exit_status = 0;
+	struct string_list matched_sparse_paths = STRING_LIST_INIT_NODUP;
 
 	if (dir->ignored_nr) {
 		fprintf(stderr, _(ignore_error));
 		for (i = 0; i < dir->ignored_nr; i++)
 			fprintf(stderr, "%s\n", dir->ignored[i]->name);
-		if (advice_add_ignored_file)
+		if (advice_enabled(ADVICE_ADD_IGNORED_FILE))
 			advise(_("Use -f if you really want to add them.\n"
 				"Turn this message off by running\n"
 				"\"git config advice.addIgnoredFile false\""));
@@ -453,6 +466,12 @@
 	}
 
 	for (i = 0; i < dir->nr; i++) {
+		if (!include_sparse &&
+		    !path_in_sparse_checkout(dir->entries[i]->name, &the_index)) {
+			string_list_append(&matched_sparse_paths,
+					   dir->entries[i]->name);
+			continue;
+		}
 		if (add_file_to_index(&the_index, dir->entries[i]->name, flags)) {
 			if (!ignore_add_errors)
 				die(_("adding files failed"));
@@ -461,6 +480,14 @@
 			check_embedded_repo(dir->entries[i]->name);
 		}
 	}
+
+	if (matched_sparse_paths.nr) {
+		advise_on_updating_sparse_paths(&matched_sparse_paths);
+		exit_status = 1;
+	}
+
+	string_list_clear(&matched_sparse_paths, 0);
+
 	return exit_status;
 }
 
@@ -526,6 +553,9 @@
 	add_new_files = !take_worktree_changes && !refresh_only && !add_renormalize;
 	require_pathspec = !(take_worktree_changes || (0 < addremove_explicit));
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
 
 	/*
@@ -551,7 +581,7 @@
 
 	if (require_pathspec && pathspec.nr == 0) {
 		fprintf(stderr, _("Nothing specified, nothing added.\n"));
-		if (advice_add_empty_pathspec)
+		if (advice_enabled(ADVICE_ADD_EMPTY_PATHSPEC))
 			advise( _("Maybe you wanted to say 'git add .'?\n"
 				"Turn this message off by running\n"
 				"\"git config advice.addEmptyPathspec false\""));
@@ -622,7 +652,8 @@
 			if (seen[i])
 				continue;
 
-			if (matches_skip_worktree(&pathspec, i, &skip_worktree_seen)) {
+			if (!include_sparse &&
+			    matches_skip_worktree(&pathspec, i, &skip_worktree_seen)) {
 				string_list_append(&only_match_skip_worktree,
 						   pathspec.items[i].original);
 				continue;
diff --git a/builtin/am.c b/builtin/am.c
index c79e016..8677ea2 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -11,6 +11,7 @@
 #include "parse-options.h"
 #include "dir.h"
 #include "run-command.h"
+#include "hook.h"
 #include "quote.h"
 #include "tempfile.h"
 #include "lockfile.h"
@@ -1820,7 +1821,7 @@
 			printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
 				linelen(state->msg), state->msg);
 
-			if (advice_amworkdir)
+			if (advice_enabled(ADVICE_AM_WORK_DIR))
 				advise(_("Use 'git am --show-current-patch=diff' to see the failed patch"));
 
 			die_user_resolve(state);
@@ -1848,7 +1849,6 @@
 	 */
 	if (!state->rebasing) {
 		am_destroy(state);
-		close_object_store(the_repository->objects);
 		run_auto_maintenance(state->quiet);
 	}
 }
@@ -1918,7 +1918,8 @@
 	opts.dst_index = &the_index;
 	opts.update = 1;
 	opts.merge = 1;
-	opts.reset = reset;
+	opts.reset = reset ? UNPACK_RESET_PROTECT_UNTRACKED : 0;
+	opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
 	opts.fn = twoway_merge;
 	init_tree_desc(&t[0], head->buffer, head->size);
 	init_tree_desc(&t[1], remote->buffer, remote->size);
diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index f184eae..28a2e6a 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -18,10 +18,10 @@
 static GIT_PATH_FUNC(git_path_head_name, "head-name")
 static GIT_PATH_FUNC(git_path_bisect_names, "BISECT_NAMES")
 static GIT_PATH_FUNC(git_path_bisect_first_parent, "BISECT_FIRST_PARENT")
+static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
 
 static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-reset [<commit>]"),
-	N_("git bisect--helper --bisect-next-check <good_term> <bad_term> [<term>]"),
 	N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
 	N_("git bisect--helper --bisect-start [--term-{new,bad}=<term> --term-{old,good}=<term>]"
 					    " [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]"),
@@ -30,6 +30,8 @@
 	N_("git bisect--helper --bisect-state (good|old) [<rev>...]"),
 	N_("git bisect--helper --bisect-replay <filename>"),
 	N_("git bisect--helper --bisect-skip [(<rev>|<range>)...]"),
+	N_("git bisect--helper --bisect-visualize"),
+	N_("git bisect--helper --bisect-run <cmd>..."),
 	NULL
 };
 
@@ -143,6 +145,19 @@
 	return res;
 }
 
+static int print_file_to_stdout(const char *path)
+{
+	int fd = open(path, O_RDONLY);
+	int ret = 0;
+
+	if (fd < 0)
+		return error_errno(_("cannot open file '%s' for reading"), path);
+	if (copy_fd(fd, 1) < 0)
+		ret = error_errno(_("failed to read '%s'"), path);
+	close(fd);
+	return ret;
+}
+
 static int check_term_format(const char *term, const char *orig_term)
 {
 	int res;
@@ -1036,6 +1051,125 @@
 	return res;
 }
 
+static int bisect_visualize(struct bisect_terms *terms, const char **argv, int argc)
+{
+	struct strvec args = STRVEC_INIT;
+	int flags = RUN_COMMAND_NO_STDIN, res = 0;
+	struct strbuf sb = STRBUF_INIT;
+
+	if (bisect_next_check(terms, NULL) != 0)
+		return BISECT_FAILED;
+
+	if (!argc) {
+		if ((getenv("DISPLAY") || getenv("SESSIONNAME") || getenv("MSYSTEM") ||
+		     getenv("SECURITYSESSIONID")) && exists_in_PATH("gitk")) {
+			strvec_push(&args, "gitk");
+		} else {
+			strvec_push(&args, "log");
+			flags |= RUN_GIT_CMD;
+		}
+	} else {
+		if (argv[0][0] == '-') {
+			strvec_push(&args, "log");
+			flags |= RUN_GIT_CMD;
+		} else if (strcmp(argv[0], "tig") && !starts_with(argv[0], "git"))
+			flags |= RUN_GIT_CMD;
+
+		strvec_pushv(&args, argv);
+	}
+
+	strvec_pushl(&args, "--bisect", "--", NULL);
+
+	strbuf_read_file(&sb, git_path_bisect_names(), 0);
+	sq_dequote_to_strvec(sb.buf, &args);
+	strbuf_release(&sb);
+
+	res = run_command_v_opt(args.v, flags);
+	strvec_clear(&args);
+	return res;
+}
+
+static int bisect_run(struct bisect_terms *terms, const char **argv, int argc)
+{
+	int res = BISECT_OK;
+	struct strbuf command = STRBUF_INIT;
+	struct strvec args = STRVEC_INIT;
+	struct strvec run_args = STRVEC_INIT;
+	const char *new_state;
+	int temporary_stdout_fd, saved_stdout;
+
+	if (bisect_next_check(terms, NULL))
+		return BISECT_FAILED;
+
+	if (argc)
+		sq_quote_argv(&command, argv);
+	else {
+		error(_("bisect run failed: no command provided."));
+		return BISECT_FAILED;
+	}
+
+	strvec_push(&run_args, command.buf);
+
+	while (1) {
+		strvec_clear(&args);
+
+		printf(_("running %s\n"), command.buf);
+		res = run_command_v_opt(run_args.v, RUN_USING_SHELL);
+
+		if (res < 0 || 128 <= res) {
+			error(_("bisect run failed: exit code %d from"
+				" '%s' is < 0 or >= 128"), res, command.buf);
+			strbuf_release(&command);
+			return res;
+		}
+
+		if (res == 125)
+			new_state = "skip";
+		else if (!res)
+			new_state = terms->term_good;
+		else
+			new_state = terms->term_bad;
+
+		temporary_stdout_fd = open(git_path_bisect_run(), O_CREAT | O_WRONLY | O_TRUNC, 0666);
+
+		if (temporary_stdout_fd < 0)
+			return error_errno(_("cannot open file '%s' for writing"), git_path_bisect_run());
+
+		fflush(stdout);
+		saved_stdout = dup(1);
+		dup2(temporary_stdout_fd, 1);
+
+		res = bisect_state(terms, &new_state, 1);
+
+		fflush(stdout);
+		dup2(saved_stdout, 1);
+		close(saved_stdout);
+		close(temporary_stdout_fd);
+
+		print_file_to_stdout(git_path_bisect_run());
+
+		if (res == BISECT_ONLY_SKIPPED_LEFT)
+			error(_("bisect run cannot continue any more"));
+		else if (res == BISECT_INTERNAL_SUCCESS_MERGE_BASE) {
+			printf(_("bisect run success"));
+			res = BISECT_OK;
+		} else if (res == BISECT_INTERNAL_SUCCESS_1ST_BAD_FOUND) {
+			printf(_("bisect found first bad commit"));
+			res = BISECT_OK;
+		} else if (res) {
+			error(_("bisect run failed: 'git bisect--helper --bisect-state"
+			" %s' exited with error code %d"), args.v[0], res);
+		} else {
+			continue;
+		}
+
+		strbuf_release(&command);
+		strvec_clear(&args);
+		strvec_clear(&run_args);
+		return res;
+	}
+}
+
 int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 {
 	enum {
@@ -1048,7 +1182,9 @@
 		BISECT_STATE,
 		BISECT_LOG,
 		BISECT_REPLAY,
-		BISECT_SKIP
+		BISECT_SKIP,
+		BISECT_VISUALIZE,
+		BISECT_RUN,
 	} cmdmode = 0;
 	int res = 0, nolog = 0;
 	struct option options[] = {
@@ -1070,6 +1206,10 @@
 			 N_("replay the bisection process from the given file"), BISECT_REPLAY),
 		OPT_CMDMODE(0, "bisect-skip", &cmdmode,
 			 N_("skip some commits for checkout"), BISECT_SKIP),
+		OPT_CMDMODE(0, "bisect-visualize", &cmdmode,
+			 N_("visualize the bisection"), BISECT_VISUALIZE),
+		OPT_CMDMODE(0, "bisect-run", &cmdmode,
+			 N_("use <cmd>... to automatically bisect."), BISECT_RUN),
 		OPT_BOOL(0, "no-log", &nolog,
 			 N_("no log for BISECT_WRITE")),
 		OPT_END()
@@ -1089,12 +1229,6 @@
 			return error(_("--bisect-reset requires either no argument or a commit"));
 		res = bisect_reset(argc ? argv[0] : NULL);
 		break;
-	case BISECT_NEXT_CHECK:
-		if (argc != 2 && argc != 3)
-			return error(_("--bisect-next-check requires 2 or 3 arguments"));
-		set_terms(&terms, argv[1], argv[0]);
-		res = bisect_next_check(&terms, argc == 3 ? argv[2] : NULL);
-		break;
 	case BISECT_TERMS:
 		if (argc > 1)
 			return error(_("--bisect-terms requires 0 or 1 argument"));
@@ -1131,6 +1265,16 @@
 		get_terms(&terms);
 		res = bisect_skip(&terms, argv, argc);
 		break;
+	case BISECT_VISUALIZE:
+		get_terms(&terms);
+		res = bisect_visualize(&terms, argv, argc);
+		break;
+	case BISECT_RUN:
+		if (!argc)
+			return error(_("bisect run failed: no command provided."));
+		get_terms(&terms);
+		res = bisect_run(&terms, argv, argc);
+		break;
 	default:
 		BUG("unknown subcommand %d", cmdmode);
 	}
diff --git a/builtin/blame.c b/builtin/blame.c
index 641523f..f9ee3f8 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -101,6 +101,16 @@
 	struct strbuf summary;
 };
 
+#define COMMIT_INFO_INIT { \
+	.author = STRBUF_INIT, \
+	.author_mail = STRBUF_INIT, \
+	.author_tz = STRBUF_INIT, \
+	.committer = STRBUF_INIT, \
+	.committer_mail = STRBUF_INIT, \
+	.committer_tz = STRBUF_INIT, \
+	.summary = STRBUF_INIT, \
+}
+
 /*
  * Parse author/committer line in the commit object buffer
  */
@@ -160,18 +170,6 @@
 	strbuf_add(name, namebuf, namelen);
 }
 
-static void commit_info_init(struct commit_info *ci)
-{
-
-	strbuf_init(&ci->author, 0);
-	strbuf_init(&ci->author_mail, 0);
-	strbuf_init(&ci->author_tz, 0);
-	strbuf_init(&ci->committer, 0);
-	strbuf_init(&ci->committer_mail, 0);
-	strbuf_init(&ci->committer_tz, 0);
-	strbuf_init(&ci->summary, 0);
-}
-
 static void commit_info_destroy(struct commit_info *ci)
 {
 
@@ -192,8 +190,6 @@
 	const char *subject, *encoding;
 	const char *message;
 
-	commit_info_init(ret);
-
 	encoding = get_log_output_encoding();
 	message = logmsg_reencode(commit, NULL, encoding);
 	get_ac_line(message, "\nauthor ",
@@ -246,7 +242,7 @@
  */
 static int emit_one_suspect_detail(struct blame_origin *suspect, int repeat)
 {
-	struct commit_info ci;
+	struct commit_info ci = COMMIT_INFO_INIT;
 
 	if (!repeat && (suspect->commit->object.flags & METAINFO_SHOWN))
 		return 0;
@@ -440,7 +436,7 @@
 	int cnt;
 	const char *cp;
 	struct blame_origin *suspect = ent->suspect;
-	struct commit_info ci;
+	struct commit_info ci = COMMIT_INFO_INIT;
 	char hex[GIT_MAX_HEXSZ + 1];
 	int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
 	const char *default_color = NULL, *color = NULL, *reset = NULL;
@@ -630,7 +626,7 @@
 		if (longest_file < num)
 			longest_file = num;
 		if (!(suspect->commit->object.flags & METAINFO_SHOWN)) {
-			struct commit_info ci;
+			struct commit_info ci = COMMIT_INFO_INIT;
 			suspect->commit->object.flags |= METAINFO_SHOWN;
 			get_commit_info(suspect->commit, &ci, 1);
 			if (*option & OUTPUT_SHOW_EMAIL)
@@ -917,6 +913,9 @@
 			    PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_ARGV0);
 	for (;;) {
 		switch (parse_options_step(&ctx, options, blame_opt_usage)) {
+		case PARSE_OPT_NON_OPTION:
+		case PARSE_OPT_UNKNOWN:
+			break;
 		case PARSE_OPT_HELP:
 		case PARSE_OPT_ERROR:
 			exit(129);
diff --git a/builtin/branch.c b/builtin/branch.c
index 03c7b72..7a1d1ee 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -407,7 +407,8 @@
 	return strbuf_detach(&fmt, NULL);
 }
 
-static void print_ref_list(struct ref_filter *filter, struct ref_sorting *sorting, struct ref_format *format)
+static void print_ref_list(struct ref_filter *filter, struct ref_sorting *sorting,
+			   struct ref_format *format, struct string_list *output)
 {
 	int i;
 	struct ref_array array;
@@ -427,7 +428,7 @@
 
 	memset(&array, 0, sizeof(array));
 
-	filter_refs(&array, filter, filter->kind | FILTER_REFS_INCLUDE_BROKEN);
+	filter_refs(&array, filter, filter->kind);
 
 	if (filter->verbose)
 		maxwidth = calc_maxwidth(&array, strlen(remote_prefix));
@@ -449,7 +450,7 @@
 		if (column_active(colopts)) {
 			assert(!filter->verbose && "--column and --verbose are incompatible");
 			 /* format to a string_list to let print_columns() do its job */
-			string_list_append(&output, out.buf);
+			string_list_append(output, out.buf);
 		} else {
 			fwrite(out.buf, 1, out.len, stdout);
 			putchar('\n');
@@ -753,9 +754,10 @@
 		ref_sorting_set_sort_flags_all(sorting, REF_SORTING_ICASE, icase);
 		ref_sorting_set_sort_flags_all(
 			sorting, REF_SORTING_DETACHED_HEAD_FIRST, 1);
-		print_ref_list(&filter, sorting, &format);
+		print_ref_list(&filter, sorting, &format, &output);
 		print_columns(&output, colopts, NULL);
 		string_list_clear(&output, 0);
+		ref_sorting_release(sorting);
 		return 0;
 	} else if (edit_description) {
 		const char *branch_name;
diff --git a/builtin/bugreport.c b/builtin/bugreport.c
index 06ed10d..9de32bc 100644
--- a/builtin/bugreport.c
+++ b/builtin/bugreport.c
@@ -3,7 +3,8 @@
 #include "strbuf.h"
 #include "help.h"
 #include "compat/compiler.h"
-#include "run-command.h"
+#include "hook.h"
+#include "hook-list.h"
 
 
 static void get_system_info(struct strbuf *sys_info)
@@ -41,39 +42,7 @@
 
 static void get_populated_hooks(struct strbuf *hook_info, int nongit)
 {
-	/*
-	 * NEEDSWORK: Doesn't look like there is a list of all possible hooks;
-	 * so below is a transcription of `git help hooks`. Later, this should
-	 * be replaced with some programmatically generated list (generated from
-	 * doc or else taken from some library which tells us about all the
-	 * hooks)
-	 */
-	static const char *hook[] = {
-		"applypatch-msg",
-		"pre-applypatch",
-		"post-applypatch",
-		"pre-commit",
-		"pre-merge-commit",
-		"prepare-commit-msg",
-		"commit-msg",
-		"post-commit",
-		"pre-rebase",
-		"post-checkout",
-		"post-merge",
-		"pre-push",
-		"pre-receive",
-		"update",
-		"post-receive",
-		"post-update",
-		"push-to-checkout",
-		"pre-auto-gc",
-		"post-rewrite",
-		"sendemail-validate",
-		"fsmonitor-watchman",
-		"p4-pre-submit",
-		"post-index-change",
-	};
-	int i;
+	const char **p;
 
 	if (nongit) {
 		strbuf_addstr(hook_info,
@@ -81,9 +50,12 @@
 		return;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(hook); i++)
-		if (find_hook(hook[i]))
-			strbuf_addf(hook_info, "%s\n", hook[i]);
+	for (p = hook_name_list; *p; p++) {
+		const char *hook = *p;
+
+		if (hook_exists(hook))
+			strbuf_addf(hook_info, "%s\n", hook);
+	}
 }
 
 static const char * const bugreport_usage[] = {
diff --git a/builtin/bundle.c b/builtin/bundle.c
index 053a51b..5a85d7c 100644
--- a/builtin/bundle.c
+++ b/builtin/bundle.c
@@ -39,8 +39,6 @@
   NULL
 };
 
-static int verbose;
-
 static int parse_options_cmd_bundle(int argc,
 		const char **argv,
 		const char* prefix,
@@ -162,10 +160,15 @@
 	struct bundle_header header = BUNDLE_HEADER_INIT;
 	int bundle_fd = -1;
 	int ret;
+	int progress = isatty(2);
+
 	struct option options[] = {
+		OPT_BOOL(0, "progress", &progress,
+			 N_("show progress meter")),
 		OPT_END()
 	};
 	char *bundle_file;
+	struct strvec extra_index_pack_args = STRVEC_INIT;
 
 	argc = parse_options_cmd_bundle(argc, argv, prefix,
 			builtin_bundle_unbundle_usage, options, &bundle_file);
@@ -177,7 +180,11 @@
 	}
 	if (!startup_info->have_repository)
 		die(_("Need a repository to unbundle."));
-	ret = !!unbundle(the_repository, &header, bundle_fd, 0) ||
+	if (progress)
+		strvec_pushl(&extra_index_pack_args, "-v", "--progress-title",
+			     _("Unbundling objects"), NULL);
+	ret = !!unbundle(the_repository, &header, bundle_fd,
+			 &extra_index_pack_args) ||
 		list_bundle_refs(&header, argc, argv);
 	bundle_header_release(&header);
 cleanup:
@@ -188,7 +195,6 @@
 int cmd_bundle(int argc, const char **argv, const char *prefix)
 {
 	struct option options[] = {
-		OPT__VERBOSE(&verbose, N_("be verbose; must be placed before a subcommand")),
 		OPT_END()
 	};
 	int result;
diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 243fe68..86fc032 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -355,18 +355,34 @@
 	}
 }
 
+/*
+ * If "pack" is non-NULL, then "offset" is the byte offset within the pack from
+ * which the object may be accessed (though note that we may also rely on
+ * data->oid, too). If "pack" is NULL, then offset is ignored.
+ */
 static void batch_object_write(const char *obj_name,
 			       struct strbuf *scratch,
 			       struct batch_options *opt,
-			       struct expand_data *data)
+			       struct expand_data *data,
+			       struct packed_git *pack,
+			       off_t offset)
 {
-	if (!data->skip_object_info &&
-	    oid_object_info_extended(the_repository, &data->oid, &data->info,
-				     OBJECT_INFO_LOOKUP_REPLACE) < 0) {
-		printf("%s missing\n",
-		       obj_name ? obj_name : oid_to_hex(&data->oid));
-		fflush(stdout);
-		return;
+	if (!data->skip_object_info) {
+		int ret;
+
+		if (pack)
+			ret = packed_object_info(the_repository, pack, offset,
+						 &data->info);
+		else
+			ret = oid_object_info_extended(the_repository,
+						       &data->oid, &data->info,
+						       OBJECT_INFO_LOOKUP_REPLACE);
+		if (ret < 0) {
+			printf("%s missing\n",
+			       obj_name ? obj_name : oid_to_hex(&data->oid));
+			fflush(stdout);
+			return;
+		}
 	}
 
 	strbuf_reset(scratch);
@@ -428,7 +444,7 @@
 		return;
 	}
 
-	batch_object_write(obj_name, scratch, opt, data);
+	batch_object_write(obj_name, scratch, opt, data, NULL, 0);
 }
 
 struct object_cb_data {
@@ -442,7 +458,8 @@
 {
 	struct object_cb_data *data = vdata;
 	oidcpy(&data->expand->oid, oid);
-	batch_object_write(NULL, data->scratch, data->opt, data->expand);
+	batch_object_write(NULL, data->scratch, data->opt, data->expand,
+			   NULL, 0);
 	return 0;
 }
 
@@ -463,21 +480,26 @@
 	return 0;
 }
 
-static int batch_unordered_object(const struct object_id *oid, void *vdata)
+static int batch_unordered_object(const struct object_id *oid,
+				  struct packed_git *pack, off_t offset,
+				  void *vdata)
 {
 	struct object_cb_data *data = vdata;
 
 	if (oidset_insert(data->seen, oid))
 		return 0;
 
-	return batch_object_cb(oid, data);
+	oidcpy(&data->expand->oid, oid);
+	batch_object_write(NULL, data->scratch, data->opt, data->expand,
+			   pack, offset);
+	return 0;
 }
 
 static int batch_unordered_loose(const struct object_id *oid,
 				 const char *path,
 				 void *data)
 {
-	return batch_unordered_object(oid, data);
+	return batch_unordered_object(oid, NULL, 0, data);
 }
 
 static int batch_unordered_packed(const struct object_id *oid,
@@ -485,7 +507,9 @@
 				  uint32_t pos,
 				  void *data)
 {
-	return batch_unordered_object(oid, data);
+	return batch_unordered_object(oid, pack,
+				      nth_packed_object_offset(pack, pos),
+				      data);
 }
 
 static int batch_objects(struct batch_options *opt)
@@ -529,6 +553,8 @@
 		if (has_promisor_remote())
 			warning("This repository uses promisor remotes. Some objects may not be loaded.");
 
+		read_replace_refs = 0;
+
 		cb.opt = opt;
 		cb.expand = &data;
 		cb.scratch = &output;
diff --git a/builtin/checkout--worker.c b/builtin/checkout--worker.c
index fb9fd13..ede7dc3 100644
--- a/builtin/checkout--worker.c
+++ b/builtin/checkout--worker.c
@@ -82,8 +82,8 @@
 	size_t i, nr = 0, alloc = 0;
 
 	while (1) {
-		int len = packet_read(0, NULL, NULL, packet_buffer,
-				      sizeof(packet_buffer), 0);
+		int len = packet_read(0, packet_buffer, sizeof(packet_buffer),
+				      0);
 
 		if (len < 0)
 			BUG("packet_read() returned negative value");
diff --git a/builtin/checkout.c b/builtin/checkout.c
index b23bc14..cbf73b8 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -646,7 +646,9 @@
 	opts.head_idx = -1;
 	opts.update = worktree;
 	opts.skip_unmerged = !worktree;
-	opts.reset = 1;
+	opts.reset = o->force ? UNPACK_RESET_OVERWRITE_UNTRACKED :
+				UNPACK_RESET_PROTECT_UNTRACKED;
+	opts.preserve_ignored = (!o->force && !o->overwrite_ignore);
 	opts.merge = 1;
 	opts.fn = oneway_merge;
 	opts.verbose_update = o->show_progress;
@@ -746,11 +748,7 @@
 				       new_branch_info->commit ?
 				       &new_branch_info->commit->object.oid :
 				       &new_branch_info->oid, NULL);
-		if (opts->overwrite_ignore) {
-			topts.dir = xcalloc(1, sizeof(*topts.dir));
-			topts.dir->flags |= DIR_SHOW_IGNORED;
-			setup_standard_excludes(topts.dir);
-		}
+		topts.preserve_ignored = !opts->overwrite_ignore;
 		tree = parse_tree_indirect(old_branch_info->commit ?
 					   &old_branch_info->commit->object.oid :
 					   the_hash_algo->empty_tree);
@@ -918,7 +916,7 @@
 			   REF_NO_DEREF, UPDATE_REFS_DIE_ON_ERR);
 		if (!opts->quiet) {
 			if (old_branch_info->path &&
-			    advice_detached_head && !opts->force_detach)
+			    advice_enabled(ADVICE_DETACHED_HEAD) && !opts->force_detach)
 				detach_advice(new_branch_info->name);
 			describe_detached_head(_("HEAD is now at"), new_branch_info->commit);
 		}
@@ -1011,7 +1009,7 @@
 		sb.buf);
 	strbuf_release(&sb);
 
-	if (advice_detached_head)
+	if (advice_enabled(ADVICE_DETACHED_HEAD))
 		fprintf(stderr,
 			Q_(
 			/* The singular version */
@@ -1182,7 +1180,7 @@
 	}
 
 	if (!remote && num_matches > 1) {
-	    if (advice_checkout_ambiguous_remote_branch_name) {
+	    if (advice_enabled(ADVICE_CHECKOUT_AMBIGUOUS_REMOTE_BRANCH_NAME)) {
 		    advise(_("If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
 			     "you can do so by fully qualifying the name with the --track option:\n"
 			     "\n"
diff --git a/builtin/clone.c b/builtin/clone.c
index 7743dc0..fb377b2 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -217,120 +217,6 @@
 	return canon;
 }
 
-static char *guess_dir_name(const char *repo, int is_bundle, int is_bare)
-{
-	const char *end = repo + strlen(repo), *start, *ptr;
-	size_t len;
-	char *dir;
-
-	/*
-	 * Skip scheme.
-	 */
-	start = strstr(repo, "://");
-	if (start == NULL)
-		start = repo;
-	else
-		start += 3;
-
-	/*
-	 * Skip authentication data. The stripping does happen
-	 * greedily, such that we strip up to the last '@' inside
-	 * the host part.
-	 */
-	for (ptr = start; ptr < end && !is_dir_sep(*ptr); ptr++) {
-		if (*ptr == '@')
-			start = ptr + 1;
-	}
-
-	/*
-	 * Strip trailing spaces, slashes and /.git
-	 */
-	while (start < end && (is_dir_sep(end[-1]) || isspace(end[-1])))
-		end--;
-	if (end - start > 5 && is_dir_sep(end[-5]) &&
-	    !strncmp(end - 4, ".git", 4)) {
-		end -= 5;
-		while (start < end && is_dir_sep(end[-1]))
-			end--;
-	}
-
-	/*
-	 * Strip trailing port number if we've got only a
-	 * hostname (that is, there is no dir separator but a
-	 * colon). This check is required such that we do not
-	 * strip URI's like '/foo/bar:2222.git', which should
-	 * result in a dir '2222' being guessed due to backwards
-	 * compatibility.
-	 */
-	if (memchr(start, '/', end - start) == NULL
-	    && memchr(start, ':', end - start) != NULL) {
-		ptr = end;
-		while (start < ptr && isdigit(ptr[-1]) && ptr[-1] != ':')
-			ptr--;
-		if (start < ptr && ptr[-1] == ':')
-			end = ptr - 1;
-	}
-
-	/*
-	 * Find last component. To remain backwards compatible we
-	 * also regard colons as path separators, such that
-	 * cloning a repository 'foo:bar.git' would result in a
-	 * directory 'bar' being guessed.
-	 */
-	ptr = end;
-	while (start < ptr && !is_dir_sep(ptr[-1]) && ptr[-1] != ':')
-		ptr--;
-	start = ptr;
-
-	/*
-	 * Strip .{bundle,git}.
-	 */
-	len = end - start;
-	strip_suffix_mem(start, &len, is_bundle ? ".bundle" : ".git");
-
-	if (!len || (len == 1 && *start == '/'))
-		die(_("No directory name could be guessed.\n"
-		      "Please specify a directory on the command line"));
-
-	if (is_bare)
-		dir = xstrfmt("%.*s.git", (int)len, start);
-	else
-		dir = xstrndup(start, len);
-	/*
-	 * Replace sequences of 'control' characters and whitespace
-	 * with one ascii space, remove leading and trailing spaces.
-	 */
-	if (*dir) {
-		char *out = dir;
-		int prev_space = 1 /* strip leading whitespace */;
-		for (end = dir; *end; ++end) {
-			char ch = *end;
-			if ((unsigned char)ch < '\x20')
-				ch = '\x20';
-			if (isspace(ch)) {
-				if (prev_space)
-					continue;
-				prev_space = 1;
-			} else
-				prev_space = 0;
-			*out++ = ch;
-		}
-		*out = '\0';
-		if (out > dir && prev_space)
-			out[-1] = '\0';
-	}
-	return dir;
-}
-
-static void strip_trailing_slashes(char *dir)
-{
-	char *end = dir + strlen(dir);
-
-	while (dir < end - 1 && is_dir_sep(end[-1]))
-		end--;
-	*end = '\0';
-}
-
 static int add_one_reference(struct string_list_item *item, void *cb_data)
 {
 	struct strbuf err = STRBUF_INIT;
@@ -657,7 +543,7 @@
 	}
 }
 
-static int iterate_ref_map(void *cb_data, struct object_id *oid)
+static const struct object_id *iterate_ref_map(void *cb_data)
 {
 	struct ref **rm = cb_data;
 	struct ref *ref = *rm;
@@ -668,13 +554,11 @@
 	 */
 	while (ref && !ref->peer_ref)
 		ref = ref->next;
-	/* Returning -1 notes "end of list" to the caller. */
 	if (!ref)
-		return -1;
+		return NULL;
 
-	oidcpy(oid, &ref->old_oid);
 	*rm = ref->next;
-	return 0;
+	return &ref->old_oid;
 }
 
 static void update_remote_refs(const struct ref *refs,
@@ -786,7 +670,7 @@
 		return 0;
 	}
 	if (!strcmp(head, "HEAD")) {
-		if (advice_detached_head)
+		if (advice_enabled(ADVICE_DETACHED_HEAD))
 			detach_advice(oid_to_hex(&oid));
 		FREE_AND_NULL(head);
 	} else {
@@ -803,6 +687,7 @@
 	opts.update = 1;
 	opts.merge = 1;
 	opts.clone = 1;
+	opts.preserve_ignored = 0;
 	opts.fn = oneway_merge;
 	opts.verbose_update = (option_verbosity >= 0);
 	opts.src_index = &the_index;
@@ -1041,8 +926,8 @@
 	if (argc == 2)
 		dir = xstrdup(argv[1]);
 	else
-		dir = guess_dir_name(repo_name, is_bundle, option_bare);
-	strip_trailing_slashes(dir);
+		dir = git_url_basename(repo_name, is_bundle, option_bare);
+	strip_dir_trailing_slashes(dir);
 
 	dest_exists = path_exists(dir);
 	if (dest_exists && !is_empty_dir(dir))
@@ -1114,6 +999,7 @@
 	if (option_recurse_submodules.nr > 0) {
 		struct string_list_item *item;
 		struct strbuf sb = STRBUF_INIT;
+		int val;
 
 		/* remove duplicates */
 		string_list_sort(&option_recurse_submodules);
@@ -1130,6 +1016,10 @@
 					   strbuf_detach(&sb, NULL));
 		}
 
+		if (!git_config_get_bool("submodule.stickyRecursiveClone", &val) &&
+		    val)
+			string_list_append(&option_config, "submodule.recurse=true");
+
 		if (option_required_reference.nr &&
 		    option_optional_reference.nr)
 			die(_("clone --recursive is not compatible with "
@@ -1150,8 +1040,10 @@
 	init_db(git_dir, real_git_dir, option_template, GIT_HASH_UNKNOWN, NULL,
 		INIT_DB_QUIET);
 
-	if (real_git_dir)
+	if (real_git_dir) {
+		free((char *)git_dir);
 		git_dir = real_git_dir;
+	}
 
 	/*
 	 * additional config can be injected with -c, make sure it's included
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index cd86315..ab8e5cd 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -9,26 +9,29 @@
 #include "progress.h"
 #include "tag.h"
 
+#define BUILTIN_COMMIT_GRAPH_VERIFY_USAGE \
+	N_("git commit-graph verify [--object-dir <objdir>] [--shallow] [--[no-]progress]")
+
+#define BUILTIN_COMMIT_GRAPH_WRITE_USAGE \
+	N_("git commit-graph write [--object-dir <objdir>] [--append] " \
+	   "[--split[=<strategy>]] [--reachable|--stdin-packs|--stdin-commits] " \
+	   "[--changed-paths] [--[no-]max-new-filters <n>] [--[no-]progress] " \
+	   "<split options>")
+
+static const char * builtin_commit_graph_verify_usage[] = {
+	BUILTIN_COMMIT_GRAPH_VERIFY_USAGE,
+	NULL
+};
+
+static const char * builtin_commit_graph_write_usage[] = {
+	BUILTIN_COMMIT_GRAPH_WRITE_USAGE,
+	NULL
+};
+
 static char const * const builtin_commit_graph_usage[] = {
-	N_("git commit-graph verify [--object-dir <objdir>] [--shallow] [--[no-]progress]"),
-	N_("git commit-graph write [--object-dir <objdir>] [--append] "
-	   "[--split[=<strategy>]] [--reachable|--stdin-packs|--stdin-commits] "
-	   "[--changed-paths] [--[no-]max-new-filters <n>] [--[no-]progress] "
-	   "<split options>"),
-	NULL
-};
-
-static const char * const builtin_commit_graph_verify_usage[] = {
-	N_("git commit-graph verify [--object-dir <objdir>] [--shallow] [--[no-]progress]"),
-	NULL
-};
-
-static const char * const builtin_commit_graph_write_usage[] = {
-	N_("git commit-graph write [--object-dir <objdir>] [--append] "
-	   "[--split[=<strategy>]] [--reachable|--stdin-packs|--stdin-commits] "
-	   "[--changed-paths] [--[no-]max-new-filters <n>] [--[no-]progress] "
-	   "<split options>"),
-	NULL
+	BUILTIN_COMMIT_GRAPH_VERIFY_USAGE,
+	BUILTIN_COMMIT_GRAPH_WRITE_USAGE,
+	NULL,
 };
 
 static struct opts_commit_graph {
@@ -43,26 +46,16 @@
 	int enable_changed_paths;
 } opts;
 
-static struct object_directory *find_odb(struct repository *r,
-					 const char *obj_dir)
+static struct option common_opts[] = {
+	OPT_STRING(0, "object-dir", &opts.obj_dir,
+		   N_("dir"),
+		   N_("the object directory to store the graph")),
+	OPT_END()
+};
+
+static struct option *add_common_options(struct option *to)
 {
-	struct object_directory *odb;
-	char *obj_dir_real = real_pathdup(obj_dir, 1);
-	struct strbuf odb_path_real = STRBUF_INIT;
-
-	prepare_alt_odb(r);
-	for (odb = r->objects->odb; odb; odb = odb->next) {
-		strbuf_realpath(&odb_path_real, odb->path, 1);
-		if (!strcmp(obj_dir_real, odb_path_real.buf))
-			break;
-	}
-
-	free(obj_dir_real);
-	strbuf_release(&odb_path_real);
-
-	if (!odb)
-		die(_("could not find object directory matching %s"), obj_dir);
-	return odb;
+	return parse_options_concat(common_opts, to);
 }
 
 static int graph_verify(int argc, const char **argv)
@@ -76,21 +69,22 @@
 	int flags = 0;
 
 	static struct option builtin_commit_graph_verify_options[] = {
-		OPT_STRING(0, "object-dir", &opts.obj_dir,
-			   N_("dir"),
-			   N_("the object directory to store the graph")),
 		OPT_BOOL(0, "shallow", &opts.shallow,
 			 N_("if the commit-graph is split, only verify the tip file")),
-		OPT_BOOL(0, "progress", &opts.progress, N_("force progress reporting")),
+		OPT_BOOL(0, "progress", &opts.progress,
+			 N_("force progress reporting")),
 		OPT_END(),
 	};
+	struct option *options = add_common_options(builtin_commit_graph_verify_options);
 
 	trace2_cmd_mode("verify");
 
 	opts.progress = isatty(2);
 	argc = parse_options(argc, argv, NULL,
-			     builtin_commit_graph_verify_options,
+			     options,
 			     builtin_commit_graph_verify_usage, 0);
+	if (argc)
+		usage_with_options(builtin_commit_graph_verify_usage, options);
 
 	if (!opts.obj_dir)
 		opts.obj_dir = get_object_directory();
@@ -106,6 +100,7 @@
 		die_errno(_("Could not open commit-graph '%s'"), graph_name);
 
 	FREE_AND_NULL(graph_name);
+	FREE_AND_NULL(options);
 
 	if (open_ok)
 		graph = load_commit_graph_one_fd_st(the_repository, fd, &st, odb);
@@ -177,8 +172,8 @@
 		const char *s;
 		*to = strtol(arg, (char **)&s, 10);
 		if (*s)
-			return error(_("%s expects a numerical value"),
-				     optname(opt, opt->flags));
+			return error(_("option `%s' expects a numerical value"),
+				     "max-new-filters");
 	}
 	return 0;
 }
@@ -206,9 +201,6 @@
 	struct progress *progress = NULL;
 
 	static struct option builtin_commit_graph_write_options[] = {
-		OPT_STRING(0, "object-dir", &opts.obj_dir,
-			N_("dir"),
-			N_("the object directory to store the graph")),
 		OPT_BOOL(0, "reachable", &opts.reachable,
 			N_("start walk at all refs")),
 		OPT_BOOL(0, "stdin-packs", &opts.stdin_packs,
@@ -219,7 +211,6 @@
 			N_("include all commits already in the commit-graph file")),
 		OPT_BOOL(0, "changed-paths", &opts.enable_changed_paths,
 			N_("enable computation for changed paths")),
-		OPT_BOOL(0, "progress", &opts.progress, N_("force progress reporting")),
 		OPT_CALLBACK_F(0, "split", &write_opts.split_flags, NULL,
 			N_("allow writing an incremental commit-graph file"),
 			PARSE_OPT_OPTARG | PARSE_OPT_NONEG,
@@ -233,8 +224,11 @@
 		OPT_CALLBACK_F(0, "max-new-filters", &write_opts.max_new_filters,
 			NULL, N_("maximum number of changed-path Bloom filters to compute"),
 			0, write_option_max_new_filters),
+		OPT_BOOL(0, "progress", &opts.progress,
+			 N_("force progress reporting")),
 		OPT_END(),
 	};
+	struct option *options = add_common_options(builtin_commit_graph_write_options);
 
 	opts.progress = isatty(2);
 	opts.enable_changed_paths = -1;
@@ -248,8 +242,10 @@
 	git_config(git_commit_graph_write_config, &opts);
 
 	argc = parse_options(argc, argv, NULL,
-			     builtin_commit_graph_write_options,
+			     options,
 			     builtin_commit_graph_write_usage, 0);
+	if (argc)
+		usage_with_options(builtin_commit_graph_write_usage, options);
 
 	if (opts.reachable + opts.stdin_packs + opts.stdin_commits > 1)
 		die(_("use at most one of --reachable, --stdin-commits, or --stdin-packs"));
@@ -304,6 +300,7 @@
 		result = 1;
 
 cleanup:
+	FREE_AND_NULL(options);
 	string_list_clear(&pack_indexes, 0);
 	strbuf_release(&buf);
 	return result;
@@ -311,32 +308,25 @@
 
 int cmd_commit_graph(int argc, const char **argv, const char *prefix)
 {
-	static struct option builtin_commit_graph_options[] = {
-		OPT_STRING(0, "object-dir", &opts.obj_dir,
-			N_("dir"),
-			N_("the object directory to store the graph")),
-		OPT_END(),
-	};
-
-	if (argc == 2 && !strcmp(argv[1], "-h"))
-		usage_with_options(builtin_commit_graph_usage,
-				   builtin_commit_graph_options);
+	struct option *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;
 
 	save_commit_buffer = 0;
 
-	if (argc > 0) {
-		if (!strcmp(argv[0], "verify"))
-			return graph_verify(argc, argv);
-		if (!strcmp(argv[0], "write"))
-			return graph_write(argc, argv);
-	}
+	if (!strcmp(argv[0], "verify"))
+		return graph_verify(argc, argv);
+	else if (argc && !strcmp(argv[0], "write"))
+		return graph_write(argc, argv);
 
+	error(_("unrecognized subcommand: %s"), argv[0]);
+usage:
 	usage_with_options(builtin_commit_graph_usage,
 			   builtin_commit_graph_options);
 }
diff --git a/builtin/commit.c b/builtin/commit.c
index 7c9b1e7..883c162 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -19,6 +19,7 @@
 #include "revision.h"
 #include "wt-status.h"
 #include "run-command.h"
+#include "hook.h"
 #include "refs.h"
 #include "log-tree.h"
 #include "strbuf.h"
@@ -203,7 +204,7 @@
 	init_diff_ui_defaults();
 	git_config(fn, s);
 	determine_whence(s);
-	s->hints = advice_status_hints; /* must come after git_config() */
+	s->hints = advice_enabled(ADVICE_STATUS_HINTS); /* must come after git_config() */
 }
 
 static void rollback_index_files(void)
@@ -1033,7 +1034,7 @@
 	 */
 	if (!committable && whence != FROM_MERGE && !allow_empty &&
 	    !(amend && is_a_merge(current_head))) {
-		s->hints = advice_status_hints;
+		s->hints = advice_enabled(ADVICE_STATUS_HINTS);
 		s->display_comment_prefix = old_display_comment_prefix;
 		run_status(stdout, index_file, prefix, 0, s);
 		if (amend)
@@ -1051,7 +1052,7 @@
 		return 0;
 	}
 
-	if (!no_verify && find_hook("pre-commit")) {
+	if (!no_verify && hook_exists("pre-commit")) {
 		/*
 		 * Re-read the index as pre-commit hook could have updated it,
 		 * and write it out as a tree.  We must do this before we invoke
diff --git a/builtin/config.c b/builtin/config.c
index 865fddd..542d8d0 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -575,7 +575,7 @@
 	int ret;
 	char *section_tail;
 	struct string_list_item *item;
-	struct urlmatch_config config = { STRING_LIST_INIT_DUP };
+	struct urlmatch_config config = URLMATCH_CONFIG_INIT;
 	struct string_list values = STRING_LIST_INIT_DUP;
 
 	config.collect_fn = urlmatch_collect_fn;
diff --git a/builtin/credential-cache.c b/builtin/credential-cache.c
index 76a6ba3..78c02ad 100644
--- a/builtin/credential-cache.c
+++ b/builtin/credential-cache.c
@@ -11,6 +11,32 @@
 #define FLAG_SPAWN 0x1
 #define FLAG_RELAY 0x2
 
+#ifdef GIT_WINDOWS_NATIVE
+
+static int connection_closed(int error)
+{
+	return (error == EINVAL);
+}
+
+static int connection_fatally_broken(int error)
+{
+	return (error != ENOENT) && (error != ENETDOWN);
+}
+
+#else
+
+static int connection_closed(int error)
+{
+	return (error == ECONNRESET);
+}
+
+static int connection_fatally_broken(int error)
+{
+	return (error != ENOENT) && (error != ECONNREFUSED);
+}
+
+#endif
+
 static int send_request(const char *socket, const struct strbuf *out)
 {
 	int got_data = 0;
@@ -28,7 +54,7 @@
 		int r;
 
 		r = read_in_full(fd, in, sizeof(in));
-		if (r == 0 || (r < 0 && errno == ECONNRESET))
+		if (r == 0 || (r < 0 && connection_closed(errno)))
 			break;
 		if (r < 0)
 			die_errno("read error from cache daemon");
@@ -75,7 +101,7 @@
 	}
 
 	if (send_request(socket, &buf) < 0) {
-		if (errno != ENOENT && errno != ECONNREFUSED)
+		if (connection_fatally_broken(errno))
 			die_errno("unable to connect to cache daemon");
 		if (flags & FLAG_SPAWN) {
 			spawn_daemon(socket);
@@ -90,7 +116,7 @@
 {
 	struct stat sb;
 	char *old_dir, *socket;
-	old_dir = expand_user_path("~/.git-credential-cache", 0);
+	old_dir = interpolate_path("~/.git-credential-cache", 0);
 	if (old_dir && !stat(old_dir, &sb) && S_ISDIR(sb.st_mode))
 		socket = xstrfmt("%s/socket", old_dir);
 	else
diff --git a/builtin/credential-store.c b/builtin/credential-store.c
index ae3c1ba..62a4f3c 100644
--- a/builtin/credential-store.c
+++ b/builtin/credential-store.c
@@ -173,7 +173,7 @@
 	if (file) {
 		string_list_append(&fns, file);
 	} else {
-		if ((file = expand_user_path("~/.git-credentials", 0)))
+		if ((file = interpolate_path("~/.git-credentials", 0)))
 			string_list_append_nodup(&fns, file);
 		file = xdg_config_home("credentials");
 		if (file)
diff --git a/builtin/difftool.c b/builtin/difftool.c
index 90c0bfc..4931c10 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -252,16 +252,6 @@
 	strbuf_release(&buf);
 }
 
-static NORETURN void exit_cleanup(const char *tmpdir, int exit_code)
-{
-	struct strbuf buf = STRBUF_INIT;
-	strbuf_addstr(&buf, tmpdir);
-	remove_dir_recursively(&buf, 0);
-	if (exit_code)
-		warning(_("failed: %d"), exit_code);
-	exit(exit_code);
-}
-
 static int ensure_leading_directories(char *path)
 {
 	switch (safe_create_leading_directories(path)) {
@@ -330,19 +320,44 @@
 	return ret;
 }
 
-static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
-			int argc, const char **argv)
+static void write_file_in_directory(struct strbuf *dir, size_t dir_len,
+			const char *path, const char *content)
 {
-	char tmpdir[PATH_MAX];
+	add_path(dir, dir_len, path);
+	ensure_leading_directories(dir->buf);
+	unlink(dir->buf);
+	write_file(dir->buf, "%s", content);
+}
+
+/* Write the file contents for the left and right sides of the difftool
+ * dir-diff representation for submodules and symlinks. Symlinks and submodules
+ * are written as regular text files so that external diff tools can diff them
+ * as text files, resulting in behavior that is analogous to to what "git diff"
+ * displays for symlink and submodule diffs.
+ */
+static void write_standin_files(struct pair_entry *entry,
+			struct strbuf *ldir, size_t ldir_len,
+			struct strbuf *rdir, size_t rdir_len)
+{
+	if (*entry->left)
+		write_file_in_directory(ldir, ldir_len, entry->path, entry->left);
+	if (*entry->right)
+		write_file_in_directory(rdir, rdir_len, entry->path, entry->right);
+}
+
+static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
+			struct child_process *child)
+{
 	struct strbuf info = STRBUF_INIT, lpath = STRBUF_INIT;
 	struct strbuf rpath = STRBUF_INIT, buf = STRBUF_INIT;
 	struct strbuf ldir = STRBUF_INIT, rdir = STRBUF_INIT;
 	struct strbuf wtdir = STRBUF_INIT;
-	char *lbase_dir, *rbase_dir;
+	struct strbuf tmpdir = STRBUF_INIT;
+	char *lbase_dir = NULL, *rbase_dir = NULL;
 	size_t ldir_len, rdir_len, wtdir_len;
 	const char *workdir, *tmp;
 	int ret = 0, i;
-	FILE *fp;
+	FILE *fp = NULL;
 	struct hashmap working_tree_dups = HASHMAP_INIT(working_tree_entry_cmp,
 							NULL);
 	struct hashmap submodules = HASHMAP_INIT(pair_cmp, NULL);
@@ -351,8 +366,7 @@
 	struct pair_entry *entry;
 	struct index_state wtindex;
 	struct checkout lstate, rstate;
-	int rc, flags = RUN_GIT_CMD, err = 0;
-	struct child_process child = CHILD_PROCESS_INIT;
+	int flags = RUN_GIT_CMD, err = 0;
 	const char *helper_argv[] = { "difftool--helper", NULL, NULL, NULL };
 	struct hashmap wt_modified, tmp_modified;
 	int indices_loaded = 0;
@@ -361,11 +375,15 @@
 
 	/* Setup temp directories */
 	tmp = getenv("TMPDIR");
-	xsnprintf(tmpdir, sizeof(tmpdir), "%s/git-difftool.XXXXXX", tmp ? tmp : "/tmp");
-	if (!mkdtemp(tmpdir))
-		return error("could not create '%s'", tmpdir);
-	strbuf_addf(&ldir, "%s/left/", tmpdir);
-	strbuf_addf(&rdir, "%s/right/", tmpdir);
+	strbuf_add_absolute_path(&tmpdir, tmp ? tmp : "/tmp");
+	strbuf_trim_trailing_dir_sep(&tmpdir);
+	strbuf_addstr(&tmpdir, "/git-difftool.XXXXXX");
+	if (!mkdtemp(tmpdir.buf)) {
+		ret = error("could not create '%s'", tmpdir.buf);
+		goto finish;
+	}
+	strbuf_addf(&ldir, "%s/left/", tmpdir.buf);
+	strbuf_addf(&rdir, "%s/right/", tmpdir.buf);
 	strbuf_addstr(&wtdir, workdir);
 	if (!wtdir.len || !is_dir_sep(wtdir.buf[wtdir.len - 1]))
 		strbuf_addch(&wtdir, '/');
@@ -387,19 +405,15 @@
 	rdir_len = rdir.len;
 	wtdir_len = wtdir.len;
 
-	child.no_stdin = 1;
-	child.git_cmd = 1;
-	child.use_shell = 0;
-	child.clean_on_exit = 1;
-	child.dir = prefix;
-	child.out = -1;
-	strvec_pushl(&child.args, "diff", "--raw", "--no-abbrev", "-z",
-		     NULL);
-	for (i = 0; i < argc; i++)
-		strvec_push(&child.args, argv[i]);
-	if (start_command(&child))
+	child->no_stdin = 1;
+	child->git_cmd = 1;
+	child->use_shell = 0;
+	child->clean_on_exit = 1;
+	child->dir = prefix;
+	child->out = -1;
+	if (start_command(child))
 		die("could not obtain raw diff");
-	fp = xfdopen(child.out, "r");
+	fp = xfdopen(child->out, "r");
 
 	/* Build index info for left and right sides of the diff */
 	i = 0;
@@ -410,9 +424,9 @@
 		const char *src_path, *dst_path;
 
 		if (starts_with(info.buf, "::"))
-			die(N_("combined diff formats('-c' and '--cc') are "
+			die(N_("combined diff formats ('-c' and '--cc') are "
 			       "not supported in\n"
-			       "directory diff mode('-d' and '--dir-diff')."));
+			       "directory diff mode ('-d' and '--dir-diff')."));
 
 		if (parse_index_info(info.buf, &lmode, &rmode, &loid, &roid,
 				     &status))
@@ -525,7 +539,7 @@
 
 	fclose(fp);
 	fp = NULL;
-	if (finish_command(&child)) {
+	if (finish_command(child)) {
 		ret = error("error occurred running diff --raw");
 		goto finish;
 	}
@@ -540,40 +554,19 @@
 	 */
 	hashmap_for_each_entry(&submodules, &iter, entry,
 				entry /* member name */) {
-		if (*entry->left) {
-			add_path(&ldir, ldir_len, entry->path);
-			ensure_leading_directories(ldir.buf);
-			write_file(ldir.buf, "%s", entry->left);
-		}
-		if (*entry->right) {
-			add_path(&rdir, rdir_len, entry->path);
-			ensure_leading_directories(rdir.buf);
-			write_file(rdir.buf, "%s", entry->right);
-		}
+		write_standin_files(entry, &ldir, ldir_len, &rdir, rdir_len);
 	}
 
 	/*
-	 * Symbolic links require special treatment.The standard "git diff"
+	 * Symbolic links require special treatment. The standard "git diff"
 	 * shows only the link itself, not the contents of the link target.
 	 * This loop replicates that behavior.
 	 */
 	hashmap_for_each_entry(&symlinks2, &iter, entry,
 				entry /* member name */) {
-		if (*entry->left) {
-			add_path(&ldir, ldir_len, entry->path);
-			ensure_leading_directories(ldir.buf);
-			unlink(ldir.buf);
-			write_file(ldir.buf, "%s", entry->left);
-		}
-		if (*entry->right) {
-			add_path(&rdir, rdir_len, entry->path);
-			ensure_leading_directories(rdir.buf);
-			unlink(rdir.buf);
-			write_file(rdir.buf, "%s", entry->right);
-		}
-	}
 
-	strbuf_release(&buf);
+		write_standin_files(entry, &ldir, ldir_len, &rdir, rdir_len);
+	}
 
 	strbuf_setlen(&ldir, ldir_len);
 	helper_argv[1] = ldir.buf;
@@ -585,7 +578,7 @@
 		flags = 0;
 	} else
 		setenv("GIT_DIFFTOOL_DIRDIFF", "true", 1);
-	rc = run_command_v_opt(helper_argv, flags);
+	ret = run_command_v_opt(helper_argv, flags);
 
 	/* TODO: audit for interaction with sparse-index. */
 	ensure_full_index(&wtindex);
@@ -619,7 +612,7 @@
 		if (!indices_loaded) {
 			struct lock_file lock = LOCK_INIT;
 			strbuf_reset(&buf);
-			strbuf_addf(&buf, "%s/wtindex", tmpdir);
+			strbuf_addf(&buf, "%s/wtindex", tmpdir.buf);
 			if (hold_lock_file_for_update(&lock, buf.buf, 0) < 0 ||
 			    write_locked_index(&wtindex, &lock, COMMIT_LOCK)) {
 				ret = error("could not write %s", buf.buf);
@@ -649,11 +642,14 @@
 	}
 
 	if (err) {
-		warning(_("temporary files exist in '%s'."), tmpdir);
+		warning(_("temporary files exist in '%s'."), tmpdir.buf);
 		warning(_("you may want to cleanup or recover these."));
-		exit(1);
-	} else
-		exit_cleanup(tmpdir, rc);
+		ret = 1;
+	} else {
+		remove_dir_recursively(&tmpdir, 0);
+		if (ret)
+			warning(_("failed: %d"), ret);
+	}
 
 finish:
 	if (fp)
@@ -665,30 +661,29 @@
 	strbuf_release(&rdir);
 	strbuf_release(&wtdir);
 	strbuf_release(&buf);
+	strbuf_release(&tmpdir);
 
-	return ret;
+	return (ret < 0) ? 1 : ret;
 }
 
 static int run_file_diff(int prompt, const char *prefix,
-			 int argc, const char **argv)
+			 struct child_process *child)
 {
-	struct strvec args = STRVEC_INIT;
 	const char *env[] = {
 		"GIT_PAGER=", "GIT_EXTERNAL_DIFF=git-difftool--helper", NULL,
 		NULL
 	};
-	int i;
 
 	if (prompt > 0)
 		env[2] = "GIT_DIFFTOOL_PROMPT=true";
 	else if (!prompt)
 		env[2] = "GIT_DIFFTOOL_NO_PROMPT=true";
 
+	child->git_cmd = 1;
+	child->dir = prefix;
+	strvec_pushv(&child->env_array, env);
 
-	strvec_push(&args, "diff");
-	for (i = 0; i < argc; i++)
-		strvec_push(&args, argv[i]);
-	return run_command_v_opt_cd_env(args.v, RUN_GIT_CMD, prefix, env);
+	return run_command(child);
 }
 
 int cmd_difftool(int argc, const char **argv, const char *prefix)
@@ -715,12 +710,13 @@
 			    "`--tool`")),
 		OPT_BOOL(0, "trust-exit-code", &trust_exit_code,
 			 N_("make 'git-difftool' exit when an invoked diff "
-			    "tool returns a non - zero exit code")),
+			    "tool returns a non-zero exit code")),
 		OPT_STRING('x', "extcmd", &extcmd, N_("command"),
 			   N_("specify a custom command for viewing diffs")),
-		OPT_ARGUMENT("no-index", &no_index, N_("passed to `diff`")),
+		OPT_BOOL(0, "no-index", &no_index, N_("passed to `diff`")),
 		OPT_END()
 	};
+	struct child_process child = CHILD_PROCESS_INIT;
 
 	git_config(difftool_config, NULL);
 	symlinks = has_symlinks;
@@ -770,7 +766,14 @@
 	 * will invoke a separate instance of 'git-difftool--helper' for
 	 * each file that changed.
 	 */
+	strvec_push(&child.args, "diff");
+	if (no_index)
+		strvec_push(&child.args, "--no-index");
 	if (dir_diff)
-		return run_dir_diff(extcmd, symlinks, prefix, argc, argv);
-	return run_file_diff(prompt, prefix, argc, argv);
+		strvec_pushl(&child.args, "--raw", "--no-abbrev", "-z", NULL);
+	strvec_pushv(&child.args, argv);
+
+	if (dir_diff)
+		return run_dir_diff(extcmd, symlinks, prefix, &child);
+	return run_file_diff(prompt, prefix, &child);
 }
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 95e8e89..8e2caf7 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -312,7 +312,7 @@
 		if (!buf)
 			die("could not read blob %s", oid_to_hex(oid));
 		if (check_object_signature(the_repository, oid, buf, size,
-					   type_name(type)) < 0)
+					   type_name(type), NULL) < 0)
 			die("oid mismatch in blob %s", oid_to_hex(oid));
 		object = parse_object_buffer(the_repository, oid, type,
 					     size, buf, &eaten);
diff --git a/builtin/fetch.c b/builtin/fetch.c
index e064687..f7abbc3 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -712,7 +712,7 @@
 	int max, rlen, llen, len;
 
 	/* uptodate lines are only shown on high verbosity level */
-	if (!verbosity && oideq(&ref->peer_ref->old_oid, &ref->old_oid))
+	if (verbosity <= 0 && oideq(&ref->peer_ref->old_oid, &ref->old_oid))
 		return;
 
 	max    = term_columns();
@@ -748,6 +748,9 @@
 	struct ref *rm;
 	const char *format = "full";
 
+	if (verbosity < 0)
+		return;
+
 	git_config_get_string_tmp("fetch.output", &format);
 	if (!strcasecmp(format, "full"))
 		compact_format = 0;
@@ -827,7 +830,12 @@
 			   const char *remote, const char *local,
 			   int summary_width)
 {
-	int width = (summary_width + strlen(summary) - gettext_width(summary));
+	int width;
+
+	if (verbosity < 0)
+		return;
+
+	width = (summary_width + strlen(summary) - gettext_width(summary));
 
 	strbuf_addf(display, "%c %-*s ", code, width, summary);
 	if (!compact_format)
@@ -846,13 +854,11 @@
 			    int summary_width)
 {
 	struct commit *current = NULL, *updated;
-	enum object_type type;
 	struct branch *current_branch = branch_get(NULL);
 	const char *pretty_ref = prettify_refname(ref->name);
 	int fast_forward = 0;
 
-	type = oid_object_info(the_repository, &ref->new_oid, NULL);
-	if (type < 0)
+	if (!repo_has_object_file(the_repository, &ref->new_oid))
 		die(_("object %s not found"), oid_to_hex(&ref->new_oid));
 
 	if (oideq(&ref->old_oid, &ref->new_oid)) {
@@ -964,7 +970,7 @@
 	}
 }
 
-static int iterate_ref_map(void *cb_data, struct object_id *oid)
+static const struct object_id *iterate_ref_map(void *cb_data)
 {
 	struct ref **rm = cb_data;
 	struct ref *ref = *rm;
@@ -972,10 +978,9 @@
 	while (ref && ref->status == REF_STATUS_REJECT_SHALLOW)
 		ref = ref->next;
 	if (!ref)
-		return -1; /* end of the list */
+		return NULL;
 	*rm = ref->next;
-	oidcpy(oid, &ref->old_oid);
-	return 0;
+	return &ref->old_oid;
 }
 
 struct fetch_head {
@@ -1074,7 +1079,6 @@
 			      int connectivity_checked, struct ref *ref_map)
 {
 	struct fetch_head fetch_head;
-	struct commit *commit;
 	int url_len, i, rc = 0;
 	struct strbuf note = STRBUF_INIT, err = STRBUF_INIT;
 	struct ref_transaction *transaction = NULL;
@@ -1122,6 +1126,7 @@
 	     want_status <= FETCH_HEAD_IGNORE;
 	     want_status++) {
 		for (rm = ref_map; rm; rm = rm->next) {
+			struct commit *commit = NULL;
 			struct ref *ref = NULL;
 
 			if (rm->status == REF_STATUS_REJECT_SHALLOW) {
@@ -1131,11 +1136,23 @@
 				continue;
 			}
 
-			commit = lookup_commit_reference_gently(the_repository,
-								&rm->old_oid,
-								1);
-			if (!commit)
-				rm->fetch_head_status = FETCH_HEAD_NOT_FOR_MERGE;
+			/*
+			 * References in "refs/tags/" are often going to point
+			 * to annotated tags, which are not part of the
+			 * commit-graph. We thus only try to look up refs in
+			 * the graph which are not in that namespace to not
+			 * regress performance in repositories with many
+			 * annotated tags.
+			 */
+			if (!starts_with(rm->name, "refs/tags/"))
+				commit = lookup_commit_in_graph(the_repository, &rm->old_oid);
+			if (!commit) {
+				commit = lookup_commit_reference_gently(the_repository,
+									&rm->old_oid,
+									1);
+				if (!commit)
+					rm->fetch_head_status = FETCH_HEAD_NOT_FOR_MERGE;
+			}
 
 			if (rm->fetch_head_status != want_status)
 				continue;
@@ -1202,13 +1219,12 @@
 					       "FETCH_HEAD", summary_width);
 			}
 			if (note.len) {
-				if (verbosity >= 0 && !shown_url) {
+				if (!shown_url) {
 					fprintf(stderr, _("From %.*s\n"),
 							url_len, url);
 					shown_url = 1;
 				}
-				if (verbosity >= 0)
-					fprintf(stderr, " %s\n", note.buf);
+				fprintf(stderr, " %s\n", note.buf);
 			}
 		}
 	}
@@ -1229,7 +1245,7 @@
 		      " 'git remote prune %s' to remove any old, conflicting "
 		      "branches"), remote_name);
 
-	if (advice_fetch_show_forced_updates) {
+	if (advice_enabled(ADVICE_FETCH_SHOW_FORCED_UPDATES)) {
 		if (!fetch_show_forced_updates) {
 			warning(_(warn_show_forced_updates));
 		} else if (forced_updates_ms > FORCED_UPDATES_DELAY_WARNING_IN_MS) {
@@ -1282,37 +1298,35 @@
 	return check_connected(iterate_ref_map, &rm, &opt);
 }
 
-static int fetch_refs(struct transport *transport, struct ref *ref_map)
+static int fetch_and_consume_refs(struct transport *transport, struct ref *ref_map)
 {
-	int ret = check_exist_and_connected(ref_map);
+	int connectivity_checked = 1;
+	int ret;
+
+	/*
+	 * We don't need to perform a fetch in case we can already satisfy all
+	 * refs.
+	 */
+	ret = check_exist_and_connected(ref_map);
 	if (ret) {
 		trace2_region_enter("fetch", "fetch_refs", the_repository);
 		ret = transport_fetch_refs(transport, ref_map);
 		trace2_region_leave("fetch", "fetch_refs", the_repository);
+		if (ret)
+			goto out;
+		connectivity_checked = transport->smart_options ?
+			transport->smart_options->connectivity_checked : 0;
 	}
-	if (!ret)
-		/*
-		 * Keep the new pack's ".keep" file around to allow the caller
-		 * time to update refs to reference the new objects.
-		 */
-		return 0;
-	transport_unlock_pack(transport);
-	return ret;
-}
 
-/* Update local refs based on the ref values fetched from a remote */
-static int consume_refs(struct transport *transport, struct ref *ref_map)
-{
-	int connectivity_checked = transport->smart_options
-		? transport->smart_options->connectivity_checked : 0;
-	int ret;
 	trace2_region_enter("fetch", "consume_refs", the_repository);
 	ret = store_updated_refs(transport->url,
 				 transport->remote->name,
 				 connectivity_checked,
 				 ref_map);
-	transport_unlock_pack(transport);
 	trace2_region_leave("fetch", "consume_refs", the_repository);
+
+out:
+	transport_unlock_pack(transport);
 	return ret;
 }
 
@@ -1501,8 +1515,7 @@
 	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);
-	if (!fetch_refs(transport, ref_map))
-		consume_refs(transport, ref_map);
+	fetch_and_consume_refs(transport, ref_map);
 
 	if (gsecondary) {
 		transport_disconnect(gsecondary);
@@ -1593,7 +1606,7 @@
 				   transport->url);
 		}
 	}
-	if (fetch_refs(transport, ref_map) || consume_refs(transport, ref_map)) {
+	if (fetch_and_consume_refs(transport, ref_map)) {
 		free_refs(ref_map);
 		retcode = 1;
 		goto cleanup;
@@ -2135,8 +2148,6 @@
 					     NULL);
 	}
 
-	close_object_store(the_repository->objects);
-
 	if (enable_auto_gc)
 		run_auto_maintenance(verbosity < 0);
 
diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c
index 89cb630..16a2c7d 100644
--- a/builtin/for-each-ref.c
+++ b/builtin/for-each-ref.c
@@ -77,7 +77,7 @@
 
 	filter.name_patterns = argv;
 	filter.match_as_path = 1;
-	filter_refs(&array, &filter, FILTER_REFS_ALL | FILTER_REFS_INCLUDE_BROKEN);
+	filter_refs(&array, &filter, FILTER_REFS_ALL);
 	ref_array_sort(sorting, &array);
 
 	if (!maxcount || array.nr < maxcount)
@@ -96,6 +96,6 @@
 	ref_array_clear(&array);
 	free_commit_list(filter.with_commit);
 	free_commit_list(filter.no_commit);
-	UNLEAK(sorting);
+	ref_sorting_release(sorting);
 	return 0;
 }
diff --git a/builtin/fsck.c b/builtin/fsck.c
index b42b6fe..30a516d 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -593,18 +593,43 @@
 	}
 }
 
+struct for_each_loose_cb
+{
+	struct progress *progress;
+	struct strbuf obj_type;
+};
+
 static int fsck_loose(const struct object_id *oid, const char *path, void *data)
 {
+	struct for_each_loose_cb *cb_data = data;
 	struct object *obj;
-	enum object_type type;
+	enum object_type type = OBJ_NONE;
 	unsigned long size;
 	void *contents;
 	int eaten;
+	struct object_info oi = OBJECT_INFO_INIT;
+	struct object_id real_oid = *null_oid();
+	int err = 0;
 
-	if (read_loose_object(path, oid, &type, &size, &contents) < 0) {
+	strbuf_reset(&cb_data->obj_type);
+	oi.type_name = &cb_data->obj_type;
+	oi.sizep = &size;
+	oi.typep = &type;
+
+	if (read_loose_object(path, oid, &real_oid, &contents, &oi) < 0) {
+		if (contents && !oideq(&real_oid, oid))
+			err = error(_("%s: hash-path mismatch, found at: %s"),
+				    oid_to_hex(&real_oid), path);
+		else
+			err = error(_("%s: object corrupt or missing: %s"),
+				    oid_to_hex(oid), path);
+	}
+	if (type != OBJ_NONE && type < 0)
+		err = error(_("%s: object is of unknown type '%s': %s"),
+			    oid_to_hex(&real_oid), cb_data->obj_type.buf,
+			    path);
+	if (err < 0) {
 		errors_found |= ERROR_OBJECT;
-		error(_("%s: object corrupt or missing: %s"),
-		      oid_to_hex(oid), path);
 		return 0; /* keep checking other objects */
 	}
 
@@ -640,8 +665,10 @@
 	return 0;
 }
 
-static int fsck_subdir(unsigned int nr, const char *path, void *progress)
+static int fsck_subdir(unsigned int nr, const char *path, void *data)
 {
+	struct for_each_loose_cb *cb_data = data;
+	struct progress *progress = cb_data->progress;
 	display_progress(progress, nr + 1);
 	return 0;
 }
@@ -649,6 +676,10 @@
 static void fsck_object_dir(const char *path)
 {
 	struct progress *progress = NULL;
+	struct for_each_loose_cb cb_data = {
+		.obj_type = STRBUF_INIT,
+		.progress = progress,
+	};
 
 	if (verbose)
 		fprintf_ln(stderr, _("Checking object directory"));
@@ -657,9 +688,10 @@
 		progress = start_progress(_("Checking object directories"), 256);
 
 	for_each_loose_file_in_objdir(path, fsck_loose, fsck_cruft, fsck_subdir,
-				      progress);
+				      &cb_data);
 	display_progress(progress, 256);
 	stop_progress(&progress);
+	strbuf_release(&cb_data.obj_type);
 }
 
 static int fsck_head_link(const char *head_ref_name,
diff --git a/builtin/gc.c b/builtin/gc.c
index ac60662..6b3de3d 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -663,8 +663,8 @@
 	gc_before_repack();
 
 	if (!repository_format_precious_objects) {
-		close_object_store(the_repository->objects);
-		if (run_command_v_opt(repack.v, RUN_GIT_CMD))
+		if (run_command_v_opt(repack.v,
+				      RUN_GIT_CMD | RUN_CLOSE_OBJECT_STORE))
 			die(FAILED_RUN, repack.v[0]);
 
 		if (prune_expire) {
@@ -848,7 +848,7 @@
 {
 	struct child_process child = CHILD_PROCESS_INIT;
 
-	child.git_cmd = 1;
+	child.git_cmd = child.close_object_store = 1;
 	strvec_pushl(&child.args, "commit-graph", "write",
 		     "--split", "--reachable", NULL);
 
@@ -864,7 +864,6 @@
 	if (!the_repository->settings.core_commit_graph)
 		return 0;
 
-	close_object_store(the_repository->objects);
 	if (run_write_commit_graph(opts)) {
 		error(_("failed to write commit-graph"));
 		return 1;
@@ -913,7 +912,7 @@
 {
 	struct child_process child = CHILD_PROCESS_INIT;
 
-	child.git_cmd = 1;
+	child.git_cmd = child.close_object_store = 1;
 	strvec_push(&child.args, "gc");
 
 	if (opts->auto_flag)
@@ -923,7 +922,6 @@
 	else
 		strvec_push(&child.args, "--no-quiet");
 
-	close_object_store(the_repository->objects);
 	return run_command(&child);
 }
 
@@ -1097,14 +1095,12 @@
 {
 	struct child_process child = CHILD_PROCESS_INIT;
 
-	child.git_cmd = 1;
+	child.git_cmd = child.close_object_store = 1;
 	strvec_pushl(&child.args, "multi-pack-index", "expire", NULL);
 
 	if (opts->quiet)
 		strvec_push(&child.args, "--no-progress");
 
-	close_object_store(the_repository->objects);
-
 	if (run_command(&child))
 		return error(_("'git multi-pack-index expire' failed"));
 
@@ -1155,7 +1151,7 @@
 {
 	struct child_process child = CHILD_PROCESS_INIT;
 
-	child.git_cmd = 1;
+	child.git_cmd = child.close_object_store = 1;
 	strvec_pushl(&child.args, "multi-pack-index", "repack", NULL);
 
 	if (opts->quiet)
@@ -1164,8 +1160,6 @@
 	strvec_pushf(&child.args, "--batch-size=%"PRIuMAX,
 				  (uintmax_t)get_auto_pack_size());
 
-	close_object_store(the_repository->objects);
-
 	if (run_command(&child))
 		return error(_("'git multi-pack-index repack' failed"));
 
@@ -1529,6 +1523,93 @@
 	}
 }
 
+/*
+ * get_schedule_cmd` reads the GIT_TEST_MAINT_SCHEDULER environment variable
+ * to mock the schedulers that `git maintenance start` rely on.
+ *
+ * For test purpose, GIT_TEST_MAINT_SCHEDULER can be set to a comma-separated
+ * list of colon-separated key/value pairs where each pair contains a scheduler
+ * and its corresponding mock.
+ *
+ * * If $GIT_TEST_MAINT_SCHEDULER is not set, return false and leave the
+ *   arguments unmodified.
+ *
+ * * If $GIT_TEST_MAINT_SCHEDULER is set, return true.
+ *   In this case, the *cmd value is read as input.
+ *
+ *   * if the input value *cmd is the key of one of the comma-separated list
+ *     item, then *is_available is set to true and *cmd is modified and becomes
+ *     the mock command.
+ *
+ *   * if the input value *cmd isn’t the key of any of the comma-separated list
+ *     item, then *is_available is set to false.
+ *
+ * Ex.:
+ *   GIT_TEST_MAINT_SCHEDULER not set
+ *     +-------+-------------------------------------------------+
+ *     | Input |                     Output                      |
+ *     | *cmd  | return code |       *cmd        | *is_available |
+ *     +-------+-------------+-------------------+---------------+
+ *     | "foo" |    false    | "foo" (unchanged) |  (unchanged)  |
+ *     +-------+-------------+-------------------+---------------+
+ *
+ *   GIT_TEST_MAINT_SCHEDULER set to “foo:./mock_foo.sh,bar:./mock_bar.sh”
+ *     +-------+-------------------------------------------------+
+ *     | Input |                     Output                      |
+ *     | *cmd  | return code |       *cmd        | *is_available |
+ *     +-------+-------------+-------------------+---------------+
+ *     | "foo" |    true     |  "./mock.foo.sh"  |     true      |
+ *     | "qux" |    true     | "qux" (unchanged) |     false     |
+ *     +-------+-------------+-------------------+---------------+
+ */
+static int get_schedule_cmd(const char **cmd, int *is_available)
+{
+	char *testing = xstrdup_or_null(getenv("GIT_TEST_MAINT_SCHEDULER"));
+	struct string_list_item *item;
+	struct string_list list = STRING_LIST_INIT_NODUP;
+
+	if (!testing)
+		return 0;
+
+	if (is_available)
+		*is_available = 0;
+
+	string_list_split_in_place(&list, testing, ',', -1);
+	for_each_string_list_item(item, &list) {
+		struct string_list pair = STRING_LIST_INIT_NODUP;
+
+		if (string_list_split_in_place(&pair, item->string, ':', 2) != 2)
+			continue;
+
+		if (!strcmp(*cmd, pair.items[0].string)) {
+			*cmd = pair.items[1].string;
+			if (is_available)
+				*is_available = 1;
+			string_list_clear(&list, 0);
+			UNLEAK(testing);
+			return 1;
+		}
+	}
+
+	string_list_clear(&list, 0);
+	free(testing);
+	return 1;
+}
+
+static int is_launchctl_available(void)
+{
+	const char *cmd = "launchctl";
+	int is_available;
+	if (get_schedule_cmd(&cmd, &is_available))
+		return is_available;
+
+#ifdef __APPLE__
+	return 1;
+#else
+	return 0;
+#endif
+}
+
 static char *launchctl_service_name(const char *frequency)
 {
 	struct strbuf label = STRBUF_INIT;
@@ -1542,7 +1623,7 @@
 	struct strbuf filename = STRBUF_INIT;
 	strbuf_addf(&filename, "~/Library/LaunchAgents/%s.plist", name);
 
-	expanded = expand_user_path(filename.buf, 1);
+	expanded = interpolate_path(filename.buf, 1);
 	if (!expanded)
 		die(_("failed to expand path '%s'"), filename.buf);
 
@@ -1555,19 +1636,17 @@
 	return xstrfmt("gui/%d", getuid());
 }
 
-static int launchctl_boot_plist(int enable, const char *filename, const char *cmd)
+static int launchctl_boot_plist(int enable, const char *filename)
 {
+	const char *cmd = "launchctl";
 	int result;
 	struct child_process child = CHILD_PROCESS_INIT;
 	char *uid = launchctl_get_uid();
 
+	get_schedule_cmd(&cmd, NULL);
 	strvec_split(&child.args, cmd);
-	if (enable)
-		strvec_push(&child.args, "bootstrap");
-	else
-		strvec_push(&child.args, "bootout");
-	strvec_push(&child.args, uid);
-	strvec_push(&child.args, filename);
+	strvec_pushl(&child.args, enable ? "bootstrap" : "bootout", uid,
+		     filename, NULL);
 
 	child.no_stderr = 1;
 	child.no_stdout = 1;
@@ -1581,30 +1660,28 @@
 	return result;
 }
 
-static int launchctl_remove_plist(enum schedule_priority schedule, const char *cmd)
+static int launchctl_remove_plist(enum schedule_priority schedule)
 {
 	const char *frequency = get_frequency(schedule);
 	char *name = launchctl_service_name(frequency);
 	char *filename = launchctl_service_filename(name);
-	int result = launchctl_boot_plist(0, filename, cmd);
+	int result = launchctl_boot_plist(0, filename);
 	unlink(filename);
 	free(filename);
 	free(name);
 	return result;
 }
 
-static int launchctl_remove_plists(const char *cmd)
+static int launchctl_remove_plists(void)
 {
-	return launchctl_remove_plist(SCHEDULE_HOURLY, cmd) ||
-		launchctl_remove_plist(SCHEDULE_DAILY, cmd) ||
-		launchctl_remove_plist(SCHEDULE_WEEKLY, cmd);
+	return launchctl_remove_plist(SCHEDULE_HOURLY) ||
+	       launchctl_remove_plist(SCHEDULE_DAILY) ||
+	       launchctl_remove_plist(SCHEDULE_WEEKLY);
 }
 
 static int launchctl_list_contains_plist(const char *name, const char *cmd)
 {
-	int result;
 	struct child_process child = CHILD_PROCESS_INIT;
-	char *uid = launchctl_get_uid();
 
 	strvec_split(&child.args, cmd);
 	strvec_pushl(&child.args, "list", name, NULL);
@@ -1615,15 +1692,11 @@
 	if (start_command(&child))
 		die(_("failed to start launchctl"));
 
-	result = finish_command(&child);
-
-	free(uid);
-
 	/* Returns failure if 'name' doesn't exist. */
-	return !result;
+	return !finish_command(&child);
 }
 
-static int launchctl_schedule_plist(const char *exec_path, enum schedule_priority schedule, const char *cmd)
+static int launchctl_schedule_plist(const char *exec_path, enum schedule_priority schedule)
 {
 	int i, fd;
 	const char *preamble, *repeat;
@@ -1634,7 +1707,9 @@
 	static unsigned long lock_file_timeout_ms = ULONG_MAX;
 	struct strbuf plist = STRBUF_INIT, plist2 = STRBUF_INIT;
 	struct stat st;
+	const char *cmd = "launchctl";
 
+	get_schedule_cmd(&cmd, NULL);
 	preamble = "<?xml version=\"1.0\"?>\n"
 		   "<!DOCTYPE plist PUBLIC \"-//Apple//DTD PLIST 1.0//EN\" \"http://www.apple.com/DTDs/PropertyList-1.0.dtd\">\n"
 		   "<plist version=\"1.0\">"
@@ -1715,8 +1790,8 @@
 			die_errno(_("could not write '%s'"), filename);
 
 		/* bootout might fail if not already running, so ignore */
-		launchctl_boot_plist(0, filename, cmd);
-		if (launchctl_boot_plist(1, filename, cmd))
+		launchctl_boot_plist(0, filename);
+		if (launchctl_boot_plist(1, filename))
 			die(_("failed to bootstrap service %s"), filename);
 	}
 
@@ -1727,21 +1802,35 @@
 	return 0;
 }
 
-static int launchctl_add_plists(const char *cmd)
+static int launchctl_add_plists(void)
 {
 	const char *exec_path = git_exec_path();
 
-	return launchctl_schedule_plist(exec_path, SCHEDULE_HOURLY, cmd) ||
-		launchctl_schedule_plist(exec_path, SCHEDULE_DAILY, cmd) ||
-		launchctl_schedule_plist(exec_path, SCHEDULE_WEEKLY, cmd);
+	return launchctl_schedule_plist(exec_path, SCHEDULE_HOURLY) ||
+	       launchctl_schedule_plist(exec_path, SCHEDULE_DAILY) ||
+	       launchctl_schedule_plist(exec_path, SCHEDULE_WEEKLY);
 }
 
-static int launchctl_update_schedule(int run_maintenance, int fd, const char *cmd)
+static int launchctl_update_schedule(int run_maintenance, int fd)
 {
 	if (run_maintenance)
-		return launchctl_add_plists(cmd);
+		return launchctl_add_plists();
 	else
-		return launchctl_remove_plists(cmd);
+		return launchctl_remove_plists();
+}
+
+static int is_schtasks_available(void)
+{
+	const char *cmd = "schtasks";
+	int is_available;
+	if (get_schedule_cmd(&cmd, &is_available))
+		return is_available;
+
+#ifdef GIT_WINDOWS_NATIVE
+	return 1;
+#else
+	return 0;
+#endif
 }
 
 static char *schtasks_task_name(const char *frequency)
@@ -1751,13 +1840,15 @@
 	return strbuf_detach(&label, NULL);
 }
 
-static int schtasks_remove_task(enum schedule_priority schedule, const char *cmd)
+static int schtasks_remove_task(enum schedule_priority schedule)
 {
+	const char *cmd = "schtasks";
 	int result;
 	struct strvec args = STRVEC_INIT;
 	const char *frequency = get_frequency(schedule);
 	char *name = schtasks_task_name(frequency);
 
+	get_schedule_cmd(&cmd, NULL);
 	strvec_split(&args, cmd);
 	strvec_pushl(&args, "/delete", "/tn", name, "/f", NULL);
 
@@ -1768,15 +1859,16 @@
 	return result;
 }
 
-static int schtasks_remove_tasks(const char *cmd)
+static int schtasks_remove_tasks(void)
 {
-	return schtasks_remove_task(SCHEDULE_HOURLY, cmd) ||
-		schtasks_remove_task(SCHEDULE_DAILY, cmd) ||
-		schtasks_remove_task(SCHEDULE_WEEKLY, cmd);
+	return schtasks_remove_task(SCHEDULE_HOURLY) ||
+	       schtasks_remove_task(SCHEDULE_DAILY) ||
+	       schtasks_remove_task(SCHEDULE_WEEKLY);
 }
 
-static int schtasks_schedule_task(const char *exec_path, enum schedule_priority schedule, const char *cmd)
+static int schtasks_schedule_task(const char *exec_path, enum schedule_priority schedule)
 {
+	const char *cmd = "schtasks";
 	int result;
 	struct child_process child = CHILD_PROCESS_INIT;
 	const char *xml;
@@ -1785,6 +1877,8 @@
 	char *name = schtasks_task_name(frequency);
 	struct strbuf tfilename = STRBUF_INIT;
 
+	get_schedule_cmd(&cmd, NULL);
+
 	strbuf_addf(&tfilename, "%s/schedule_%s_XXXXXX",
 		    get_git_common_dir(), frequency);
 	tfile = xmks_tempfile(tfilename.buf);
@@ -1889,28 +1983,52 @@
 	return result;
 }
 
-static int schtasks_schedule_tasks(const char *cmd)
+static int schtasks_schedule_tasks(void)
 {
 	const char *exec_path = git_exec_path();
 
-	return schtasks_schedule_task(exec_path, SCHEDULE_HOURLY, cmd) ||
-		schtasks_schedule_task(exec_path, SCHEDULE_DAILY, cmd) ||
-		schtasks_schedule_task(exec_path, SCHEDULE_WEEKLY, cmd);
+	return schtasks_schedule_task(exec_path, SCHEDULE_HOURLY) ||
+	       schtasks_schedule_task(exec_path, SCHEDULE_DAILY) ||
+	       schtasks_schedule_task(exec_path, SCHEDULE_WEEKLY);
 }
 
-static int schtasks_update_schedule(int run_maintenance, int fd, const char *cmd)
+static int schtasks_update_schedule(int run_maintenance, int fd)
 {
 	if (run_maintenance)
-		return schtasks_schedule_tasks(cmd);
+		return schtasks_schedule_tasks();
 	else
-		return schtasks_remove_tasks(cmd);
+		return schtasks_remove_tasks();
+}
+
+static int is_crontab_available(void)
+{
+	const char *cmd = "crontab";
+	int is_available;
+	struct child_process child = CHILD_PROCESS_INIT;
+
+	if (get_schedule_cmd(&cmd, &is_available))
+		return is_available;
+
+	strvec_split(&child.args, cmd);
+	strvec_push(&child.args, "-l");
+	child.no_stdin = 1;
+	child.no_stdout = 1;
+	child.no_stderr = 1;
+	child.silent_exec_failure = 1;
+
+	if (start_command(&child))
+		return 0;
+	/* Ignore exit code, as an empty crontab will return error. */
+	finish_command(&child);
+	return 1;
 }
 
 #define BEGIN_LINE "# BEGIN GIT MAINTENANCE SCHEDULE"
 #define END_LINE "# END GIT MAINTENANCE SCHEDULE"
 
-static int crontab_update_schedule(int run_maintenance, int fd, const char *cmd)
+static int crontab_update_schedule(int run_maintenance, int fd)
 {
+	const char *cmd = "crontab";
 	int result = 0;
 	int in_old_region = 0;
 	struct child_process crontab_list = CHILD_PROCESS_INIT;
@@ -1918,6 +2036,7 @@
 	FILE *cron_list, *cron_in;
 	struct strbuf line = STRBUF_INIT;
 
+	get_schedule_cmd(&cmd, NULL);
 	strvec_split(&crontab_list.args, cmd);
 	strvec_push(&crontab_list.args, "-l");
 	crontab_list.in = -1;
@@ -1994,66 +2113,376 @@
 	return result;
 }
 
-#if defined(__APPLE__)
-static const char platform_scheduler[] = "launchctl";
-#elif defined(GIT_WINDOWS_NATIVE)
-static const char platform_scheduler[] = "schtasks";
-#else
-static const char platform_scheduler[] = "crontab";
-#endif
-
-static int update_background_schedule(int enable)
+static int real_is_systemd_timer_available(void)
 {
-	int result;
-	const char *scheduler = platform_scheduler;
-	const char *cmd = scheduler;
-	char *testing;
+	struct child_process child = CHILD_PROCESS_INIT;
+
+	strvec_pushl(&child.args, "systemctl", "--user", "list-timers", NULL);
+	child.no_stdin = 1;
+	child.no_stdout = 1;
+	child.no_stderr = 1;
+	child.silent_exec_failure = 1;
+
+	if (start_command(&child))
+		return 0;
+	if (finish_command(&child))
+		return 0;
+	return 1;
+}
+
+static int is_systemd_timer_available(void)
+{
+	const char *cmd = "systemctl";
+	int is_available;
+
+	if (get_schedule_cmd(&cmd, &is_available))
+		return is_available;
+
+	return real_is_systemd_timer_available();
+}
+
+static char *xdg_config_home_systemd(const char *filename)
+{
+	return xdg_config_home_for("systemd/user", filename);
+}
+
+static int systemd_timer_enable_unit(int enable,
+				     enum schedule_priority schedule)
+{
+	const char *cmd = "systemctl";
+	struct child_process child = CHILD_PROCESS_INIT;
+	const char *frequency = get_frequency(schedule);
+
+	/*
+	 * Disabling the systemd unit while it is already disabled makes
+	 * systemctl print an error.
+	 * Let's ignore it since it means we already are in the expected state:
+	 * the unit is disabled.
+	 *
+	 * On the other hand, enabling a systemd unit which is already enabled
+	 * produces no error.
+	 */
+	if (!enable)
+		child.no_stderr = 1;
+
+	get_schedule_cmd(&cmd, NULL);
+	strvec_split(&child.args, cmd);
+	strvec_pushl(&child.args, "--user", enable ? "enable" : "disable",
+		     "--now", NULL);
+	strvec_pushf(&child.args, "git-maintenance@%s.timer", frequency);
+
+	if (start_command(&child))
+		return error(_("failed to start systemctl"));
+	if (finish_command(&child))
+		/*
+		 * Disabling an already disabled systemd unit makes
+		 * systemctl fail.
+		 * Let's ignore this failure.
+		 *
+		 * Enabling an enabled systemd unit doesn't fail.
+		 */
+		if (enable)
+			return error(_("failed to run systemctl"));
+	return 0;
+}
+
+static int systemd_timer_delete_unit_templates(void)
+{
+	int ret = 0;
+	char *filename = xdg_config_home_systemd("git-maintenance@.timer");
+	if (unlink(filename) && !is_missing_file_error(errno))
+		ret = error_errno(_("failed to delete '%s'"), filename);
+	FREE_AND_NULL(filename);
+
+	filename = xdg_config_home_systemd("git-maintenance@.service");
+	if (unlink(filename) && !is_missing_file_error(errno))
+		ret = error_errno(_("failed to delete '%s'"), filename);
+
+	free(filename);
+	return ret;
+}
+
+static int systemd_timer_delete_units(void)
+{
+	return systemd_timer_enable_unit(0, SCHEDULE_HOURLY) ||
+	       systemd_timer_enable_unit(0, SCHEDULE_DAILY) ||
+	       systemd_timer_enable_unit(0, SCHEDULE_WEEKLY) ||
+	       systemd_timer_delete_unit_templates();
+}
+
+static int systemd_timer_write_unit_templates(const char *exec_path)
+{
+	char *filename;
+	FILE *file;
+	const char *unit;
+
+	filename = xdg_config_home_systemd("git-maintenance@.timer");
+	if (safe_create_leading_directories(filename)) {
+		error(_("failed to create directories for '%s'"), filename);
+		goto error;
+	}
+	file = fopen_or_warn(filename, "w");
+	if (file == NULL)
+		goto error;
+
+	unit = "# This file was created and is maintained by Git.\n"
+	       "# Any edits made in this file might be replaced in the future\n"
+	       "# by a Git command.\n"
+	       "\n"
+	       "[Unit]\n"
+	       "Description=Optimize Git repositories data\n"
+	       "\n"
+	       "[Timer]\n"
+	       "OnCalendar=%i\n"
+	       "Persistent=true\n"
+	       "\n"
+	       "[Install]\n"
+	       "WantedBy=timers.target\n";
+	if (fputs(unit, file) == EOF) {
+		error(_("failed to write to '%s'"), filename);
+		fclose(file);
+		goto error;
+	}
+	if (fclose(file) == EOF) {
+		error_errno(_("failed to flush '%s'"), filename);
+		goto error;
+	}
+	free(filename);
+
+	filename = xdg_config_home_systemd("git-maintenance@.service");
+	file = fopen_or_warn(filename, "w");
+	if (file == NULL)
+		goto error;
+
+	unit = "# This file was created and is maintained by Git.\n"
+	       "# Any edits made in this file might be replaced in the future\n"
+	       "# by a Git command.\n"
+	       "\n"
+	       "[Unit]\n"
+	       "Description=Optimize Git repositories data\n"
+	       "\n"
+	       "[Service]\n"
+	       "Type=oneshot\n"
+	       "ExecStart=\"%s/git\" --exec-path=\"%s\" for-each-repo --config=maintenance.repo maintenance run --schedule=%%i\n"
+	       "LockPersonality=yes\n"
+	       "MemoryDenyWriteExecute=yes\n"
+	       "NoNewPrivileges=yes\n"
+	       "RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6\n"
+	       "RestrictNamespaces=yes\n"
+	       "RestrictRealtime=yes\n"
+	       "RestrictSUIDSGID=yes\n"
+	       "SystemCallArchitectures=native\n"
+	       "SystemCallFilter=@system-service\n";
+	if (fprintf(file, unit, exec_path, exec_path) < 0) {
+		error(_("failed to write to '%s'"), filename);
+		fclose(file);
+		goto error;
+	}
+	if (fclose(file) == EOF) {
+		error_errno(_("failed to flush '%s'"), filename);
+		goto error;
+	}
+	free(filename);
+	return 0;
+
+error:
+	free(filename);
+	systemd_timer_delete_unit_templates();
+	return -1;
+}
+
+static int systemd_timer_setup_units(void)
+{
+	const char *exec_path = git_exec_path();
+
+	int ret = systemd_timer_write_unit_templates(exec_path) ||
+		  systemd_timer_enable_unit(1, SCHEDULE_HOURLY) ||
+		  systemd_timer_enable_unit(1, SCHEDULE_DAILY) ||
+		  systemd_timer_enable_unit(1, SCHEDULE_WEEKLY);
+	if (ret)
+		systemd_timer_delete_units();
+	return ret;
+}
+
+static int systemd_timer_update_schedule(int run_maintenance, int fd)
+{
+	if (run_maintenance)
+		return systemd_timer_setup_units();
+	else
+		return systemd_timer_delete_units();
+}
+
+enum scheduler {
+	SCHEDULER_INVALID = -1,
+	SCHEDULER_AUTO,
+	SCHEDULER_CRON,
+	SCHEDULER_SYSTEMD,
+	SCHEDULER_LAUNCHCTL,
+	SCHEDULER_SCHTASKS,
+};
+
+static const struct {
+	const char *name;
+	int (*is_available)(void);
+	int (*update_schedule)(int run_maintenance, int fd);
+} scheduler_fn[] = {
+	[SCHEDULER_CRON] = {
+		.name = "crontab",
+		.is_available = is_crontab_available,
+		.update_schedule = crontab_update_schedule,
+	},
+	[SCHEDULER_SYSTEMD] = {
+		.name = "systemctl",
+		.is_available = is_systemd_timer_available,
+		.update_schedule = systemd_timer_update_schedule,
+	},
+	[SCHEDULER_LAUNCHCTL] = {
+		.name = "launchctl",
+		.is_available = is_launchctl_available,
+		.update_schedule = launchctl_update_schedule,
+	},
+	[SCHEDULER_SCHTASKS] = {
+		.name = "schtasks",
+		.is_available = is_schtasks_available,
+		.update_schedule = schtasks_update_schedule,
+	},
+};
+
+static enum scheduler parse_scheduler(const char *value)
+{
+	if (!value)
+		return SCHEDULER_INVALID;
+	else if (!strcasecmp(value, "auto"))
+		return SCHEDULER_AUTO;
+	else if (!strcasecmp(value, "cron") || !strcasecmp(value, "crontab"))
+		return SCHEDULER_CRON;
+	else if (!strcasecmp(value, "systemd") ||
+		 !strcasecmp(value, "systemd-timer"))
+		return SCHEDULER_SYSTEMD;
+	else if (!strcasecmp(value, "launchctl"))
+		return SCHEDULER_LAUNCHCTL;
+	else if (!strcasecmp(value, "schtasks"))
+		return SCHEDULER_SCHTASKS;
+	else
+		return SCHEDULER_INVALID;
+}
+
+static int maintenance_opt_scheduler(const struct option *opt, const char *arg,
+				     int unset)
+{
+	enum scheduler *scheduler = opt->value;
+
+	BUG_ON_OPT_NEG(unset);
+
+	*scheduler = parse_scheduler(arg);
+	if (*scheduler == SCHEDULER_INVALID)
+		return error(_("unrecognized --scheduler argument '%s'"), arg);
+	return 0;
+}
+
+struct maintenance_start_opts {
+	enum scheduler scheduler;
+};
+
+static enum scheduler resolve_scheduler(enum scheduler scheduler)
+{
+	if (scheduler != SCHEDULER_AUTO)
+		return scheduler;
+
+#if defined(__APPLE__)
+	return SCHEDULER_LAUNCHCTL;
+
+#elif defined(GIT_WINDOWS_NATIVE)
+	return SCHEDULER_SCHTASKS;
+
+#elif defined(__linux__)
+	if (is_systemd_timer_available())
+		return SCHEDULER_SYSTEMD;
+	else if (is_crontab_available())
+		return SCHEDULER_CRON;
+	else
+		die(_("neither systemd timers nor crontab are available"));
+
+#else
+	return SCHEDULER_CRON;
+#endif
+}
+
+static void validate_scheduler(enum scheduler scheduler)
+{
+	if (scheduler == SCHEDULER_INVALID)
+		BUG("invalid scheduler");
+	if (scheduler == SCHEDULER_AUTO)
+		BUG("resolve_scheduler should have been called before");
+
+	if (!scheduler_fn[scheduler].is_available())
+		die(_("%s scheduler is not available"),
+		    scheduler_fn[scheduler].name);
+}
+
+static int update_background_schedule(const struct maintenance_start_opts *opts,
+				      int enable)
+{
+	unsigned int i;
+	int result = 0;
 	struct lock_file lk;
 	char *lock_path = xstrfmt("%s/schedule", the_repository->objects->odb->path);
 
-	testing = xstrdup_or_null(getenv("GIT_TEST_MAINT_SCHEDULER"));
-	if (testing) {
-		char *sep = strchr(testing, ':');
-		if (!sep)
-			die("GIT_TEST_MAINT_SCHEDULER unparseable: %s", testing);
-		*sep = '\0';
-		scheduler = testing;
-		cmd = sep + 1;
-	}
-
 	if (hold_lock_file_for_update(&lk, lock_path, LOCK_NO_DEREF) < 0) {
-		result = error(_("another process is scheduling background maintenance"));
-		goto cleanup;
+		free(lock_path);
+		return error(_("another process is scheduling background maintenance"));
 	}
 
-	if (!strcmp(scheduler, "launchctl"))
-		result = launchctl_update_schedule(enable, get_lock_file_fd(&lk), cmd);
-	else if (!strcmp(scheduler, "schtasks"))
-		result = schtasks_update_schedule(enable, get_lock_file_fd(&lk), cmd);
-	else if (!strcmp(scheduler, "crontab"))
-		result = crontab_update_schedule(enable, get_lock_file_fd(&lk), cmd);
-	else
-		die("unknown background scheduler: %s", scheduler);
+	for (i = 1; i < ARRAY_SIZE(scheduler_fn); i++) {
+		if (enable && opts->scheduler == i)
+			continue;
+		if (!scheduler_fn[i].is_available())
+			continue;
+		scheduler_fn[i].update_schedule(0, get_lock_file_fd(&lk));
+	}
+
+	if (enable)
+		result = scheduler_fn[opts->scheduler].update_schedule(
+			1, get_lock_file_fd(&lk));
 
 	rollback_lock_file(&lk);
 
-cleanup:
 	free(lock_path);
-	free(testing);
 	return result;
 }
 
-static int maintenance_start(void)
+static const char *const builtin_maintenance_start_usage[] = {
+	N_("git maintenance start [--scheduler=<scheduler>]"),
+	NULL
+};
+
+static int maintenance_start(int argc, const char **argv, const char *prefix)
 {
+	struct maintenance_start_opts opts = { 0 };
+	struct option options[] = {
+		OPT_CALLBACK_F(
+			0, "scheduler", &opts.scheduler, N_("scheduler"),
+			N_("scheduler to trigger git maintenance run"),
+			PARSE_OPT_NONEG, maintenance_opt_scheduler),
+		OPT_END()
+	};
+
+	argc = parse_options(argc, argv, prefix, options,
+			     builtin_maintenance_start_usage, 0);
+	if (argc)
+		usage_with_options(builtin_maintenance_start_usage, options);
+
+	opts.scheduler = resolve_scheduler(opts.scheduler);
+	validate_scheduler(opts.scheduler);
+
 	if (maintenance_register())
 		warning(_("failed to add repo to global config"));
-
-	return update_background_schedule(1);
+	return update_background_schedule(&opts, 1);
 }
 
 static int maintenance_stop(void)
 {
-	return update_background_schedule(0);
+	return update_background_schedule(NULL, 0);
 }
 
 static const char builtin_maintenance_usage[] =	N_("git maintenance <subcommand> [<options>]");
@@ -2067,7 +2496,7 @@
 	if (!strcmp(argv[1], "run"))
 		return maintenance_run(argc - 1, argv + 1, prefix);
 	if (!strcmp(argv[1], "start"))
-		return maintenance_start();
+		return maintenance_start(argc - 1, argv + 1, prefix);
 	if (!strcmp(argv[1], "stop"))
 		return maintenance_stop();
 	if (!strcmp(argv[1], "register"))
diff --git a/builtin/grep.c b/builtin/grep.c
index 7d2f8e5..9e34a82 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -65,6 +65,9 @@
 /* Has all work items been added? */
 static int all_work_added;
 
+static struct repository **repos_to_free;
+static size_t repos_to_free_nr, repos_to_free_alloc;
+
 /* This lock protects all the variables above. */
 static pthread_mutex_t grep_mutex;
 
@@ -168,6 +171,19 @@
 	grep_unlock();
 }
 
+static void free_repos(void)
+{
+	int i;
+
+	for (i = 0; i < repos_to_free_nr; i++) {
+		repo_clear(repos_to_free[i]);
+		free(repos_to_free[i]);
+	}
+	FREE_AND_NULL(repos_to_free);
+	repos_to_free_nr = 0;
+	repos_to_free_alloc = 0;
+}
+
 static void *run(void *arg)
 {
 	int hit = 0;
@@ -183,8 +199,8 @@
 		grep_source_clear_data(&w->source);
 		work_done(w);
 	}
-	free_grep_patterns(arg);
-	free(arg);
+	free_grep_patterns(opt);
+	free(opt);
 
 	return (void*) (intptr_t) hit;
 }
@@ -333,7 +349,7 @@
 	struct grep_source gs;
 
 	grep_source_name(opt, filename, tree_name_len, &pathbuf);
-	grep_source_init(&gs, GREP_SOURCE_OID, pathbuf.buf, path, oid);
+	grep_source_init_oid(&gs, pathbuf.buf, path, oid, opt->repo);
 	strbuf_release(&pathbuf);
 
 	if (num_threads > 1) {
@@ -359,7 +375,7 @@
 	struct grep_source gs;
 
 	grep_source_name(opt, filename, 0, &buf);
-	grep_source_init(&gs, GREP_SOURCE_FILE, buf.buf, filename, filename);
+	grep_source_init_file(&gs, buf.buf, filename);
 	strbuf_release(&buf);
 
 	if (num_threads > 1) {
@@ -385,7 +401,7 @@
 
 	if (len == 1 && *(const char *)data == '\0')
 		return;
-	string_list_append(path_list, xstrndup(data, len));
+	string_list_append_nodup(path_list, xstrndup(data, len));
 }
 
 static void run_pager(struct grep_opt *opt, const char *prefix)
@@ -415,19 +431,21 @@
 			  const struct object_id *oid,
 			  const char *filename, const char *path, int cached)
 {
-	struct repository subrepo;
+	struct repository *subrepo;
 	struct repository *superproject = opt->repo;
-	const struct submodule *sub;
 	struct grep_opt subopt;
-	int hit;
-
-	sub = submodule_from_path(superproject, null_oid(), path);
+	int hit = 0;
 
 	if (!is_submodule_active(superproject, path))
 		return 0;
 
-	if (repo_submodule_init(&subrepo, superproject, sub))
+	subrepo = xmalloc(sizeof(*subrepo));
+	if (repo_submodule_init(subrepo, superproject, path, null_oid())) {
+		free(subrepo);
 		return 0;
+	}
+	ALLOC_GROW(repos_to_free, repos_to_free_nr + 1, repos_to_free_alloc);
+	repos_to_free[repos_to_free_nr++] = subrepo;
 
 	/*
 	 * NEEDSWORK: repo_read_gitmodules() might call
@@ -438,53 +456,49 @@
 	 * subrepo's odbs to the in-memory alternates list.
 	 */
 	obj_read_lock();
-	repo_read_gitmodules(&subrepo, 0);
+	repo_read_gitmodules(subrepo, 0);
 
 	/*
-	 * NEEDSWORK: This adds the submodule's object directory to the list of
-	 * alternates for the single in-memory object store.  This has some bad
-	 * consequences for memory (processed objects will never be freed) and
-	 * performance (this increases the number of pack files git has to pay
-	 * attention to, to the sum of the number of pack files in all the
-	 * repositories processed so far).  This can be removed once the object
-	 * store is no longer global and instead is a member of the repository
-	 * object.
+	 * All code paths tested by test code no longer need submodule ODBs to
+	 * be added as alternates, but add it to the list just in case.
+	 * Submodule ODBs added through add_submodule_odb_by_path() will be
+	 * lazily registered as alternates when needed (and except in an
+	 * unexpected code interaction, it won't be needed).
 	 */
-	add_to_alternates_memory(subrepo.objects->odb->path);
+	add_submodule_odb_by_path(subrepo->objects->odb->path);
 	obj_read_unlock();
 
 	memcpy(&subopt, opt, sizeof(subopt));
-	subopt.repo = &subrepo;
+	subopt.repo = subrepo;
 
 	if (oid) {
-		struct object *object;
+		enum object_type object_type;
 		struct tree_desc tree;
 		void *data;
 		unsigned long size;
 		struct strbuf base = STRBUF_INIT;
 
 		obj_read_lock();
-		object = parse_object_or_die(oid, NULL);
+		object_type = oid_object_info(subrepo, oid, NULL);
 		obj_read_unlock();
-		data = read_object_with_reference(&subrepo,
-						  &object->oid, tree_type,
+		data = read_object_with_reference(subrepo,
+						  oid, tree_type,
 						  &size, NULL);
 		if (!data)
-			die(_("unable to read tree (%s)"), oid_to_hex(&object->oid));
+			die(_("unable to read tree (%s)"), oid_to_hex(oid));
 
 		strbuf_addstr(&base, filename);
 		strbuf_addch(&base, '/');
 
 		init_tree_desc(&tree, data, size);
 		hit = grep_tree(&subopt, pathspec, &tree, &base, base.len,
-				object->type == OBJ_COMMIT);
+				object_type == OBJ_COMMIT);
 		strbuf_release(&base);
 		free(data);
 	} else {
 		hit = grep_cache(&subopt, pathspec, cached);
 	}
 
-	repo_clear(&subrepo);
 	return hit;
 }
 
@@ -825,7 +839,7 @@
 	struct grep_opt opt;
 	struct object_array list = OBJECT_ARRAY_INIT;
 	struct pathspec pathspec;
-	struct string_list path_list = STRING_LIST_INIT_NODUP;
+	struct string_list path_list = STRING_LIST_INIT_DUP;
 	int i;
 	int dummy;
 	int use_index = 1;
@@ -1145,8 +1159,8 @@
 			strbuf_addf(&buf, "+/%s%s",
 					strcmp("less", pager) ? "" : "*",
 					opt.pattern_list->pattern);
-			string_list_append(&path_list,
-					   strbuf_detach(&buf, NULL));
+			string_list_append_nodup(&path_list,
+						 strbuf_detach(&buf, NULL));
 		}
 	}
 
@@ -1181,6 +1195,9 @@
 	if (hit && show_in_pager)
 		run_pager(&opt, prefix);
 	clear_pathspec(&pathspec);
+	string_list_clear(&path_list, 0);
 	free_grep_patterns(&opt);
+	object_array_clear(&list);
+	free_repos();
 	return !hit;
 }
diff --git a/builtin/help.c b/builtin/help.c
index b7eec06..75cd2fb 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -7,7 +7,6 @@
 #include "exec-cmd.h"
 #include "parse-options.h"
 #include "run-command.h"
-#include "column.h"
 #include "config-list.h"
 #include "help.h"
 #include "alias.h"
@@ -34,32 +33,52 @@
 	HELP_FORMAT_WEB
 };
 
-static const char *html_path;
+enum show_config_type {
+	SHOW_CONFIG_HUMAN,
+	SHOW_CONFIG_VARS,
+	SHOW_CONFIG_SECTIONS,
+};
 
-static int show_all = 0;
-static int show_guides = 0;
-static int show_config;
+static enum help_action {
+	HELP_ACTION_ALL = 1,
+	HELP_ACTION_GUIDES,
+	HELP_ACTION_CONFIG,
+	HELP_ACTION_CONFIG_FOR_COMPLETION,
+	HELP_ACTION_CONFIG_SECTIONS_FOR_COMPLETION,
+} cmd_mode;
+
+static const char *html_path;
 static int verbose = 1;
-static unsigned int colopts;
 static enum help_format help_format = HELP_FORMAT_NONE;
 static int exclude_guides;
 static struct option builtin_help_options[] = {
-	OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
+	OPT_CMDMODE('a', "all", &cmd_mode, N_("print all available commands"),
+		    HELP_ACTION_ALL),
 	OPT_HIDDEN_BOOL(0, "exclude-guides", &exclude_guides, N_("exclude guides")),
-	OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
-	OPT_BOOL('c', "config", &show_config, N_("print all configuration variable names")),
-	OPT_SET_INT_F(0, "config-for-completion", &show_config, "", 2, PARSE_OPT_HIDDEN),
 	OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
 	OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
 			HELP_FORMAT_WEB),
 	OPT_SET_INT('i', "info", &help_format, N_("show info page"),
 			HELP_FORMAT_INFO),
 	OPT__VERBOSE(&verbose, N_("print command description")),
+
+	OPT_CMDMODE('g', "guides", &cmd_mode, N_("print list of useful guides"),
+		    HELP_ACTION_GUIDES),
+	OPT_CMDMODE('c', "config", &cmd_mode, N_("print all configuration variable names"),
+		    HELP_ACTION_CONFIG),
+	OPT_CMDMODE_F(0, "config-for-completion", &cmd_mode, "",
+		    HELP_ACTION_CONFIG_FOR_COMPLETION, PARSE_OPT_HIDDEN),
+	OPT_CMDMODE_F(0, "config-sections-for-completion", &cmd_mode, "",
+		    HELP_ACTION_CONFIG_SECTIONS_FOR_COMPLETION, PARSE_OPT_HIDDEN),
+
 	OPT_END(),
 };
 
 static const char * const builtin_help_usage[] = {
-	N_("git help [--all] [--guides] [--man | --web | --info] [<command>]"),
+	N_("git help [-a|--all] [--[no-]verbose]]\n"
+	   "         [[-i|--info] [-m|--man] [-w|--web]] [<command>]"),
+	N_("git help [-g|--guides]"),
+	N_("git help [-c|--config]"),
 	NULL
 };
 
@@ -70,7 +89,7 @@
 	int found;
 };
 
-static void list_config_help(int for_human)
+static void list_config_help(enum show_config_type type)
 {
 	struct slot_expansion slot_expansions[] = {
 		{ "advice", "*", list_config_advices },
@@ -88,6 +107,8 @@
 	const char **p;
 	struct slot_expansion *e;
 	struct string_list keys = STRING_LIST_INIT_DUP;
+	struct string_list keys_uniq = STRING_LIST_INIT_DUP;
+	struct string_list_item *item;
 	int i;
 
 	for (p = config_name_list; *p; p++) {
@@ -118,34 +139,46 @@
 	for (i = 0; i < keys.nr; i++) {
 		const char *var = keys.items[i].string;
 		const char *wildcard, *tag, *cut;
+		const char *dot = NULL;
+		struct strbuf sb = STRBUF_INIT;
 
-		if (for_human) {
+		switch (type) {
+		case SHOW_CONFIG_HUMAN:
 			puts(var);
 			continue;
+		case SHOW_CONFIG_SECTIONS:
+			dot = strchr(var, '.');
+			break;
+		case SHOW_CONFIG_VARS:
+			break;
 		}
-
 		wildcard = strchr(var, '*');
 		tag = strchr(var, '<');
 
-		if (!wildcard && !tag) {
-			puts(var);
+		if (!dot && !wildcard && !tag) {
+			string_list_append(&keys_uniq, var);
 			continue;
 		}
 
-		if (wildcard && !tag)
+		if (dot)
+			cut = dot;
+		else if (wildcard && !tag)
 			cut = wildcard;
 		else if (!wildcard && tag)
 			cut = tag;
 		else
 			cut = wildcard < tag ? wildcard : tag;
 
-		/*
-		 * We may produce duplicates, but that's up to
-		 * git-completion.bash to handle
-		 */
-		printf("%.*s\n", (int)(cut - var), var);
+		strbuf_add(&sb, var, cut - var);
+		string_list_append(&keys_uniq, sb.buf);
+		strbuf_release(&sb);
+
 	}
 	string_list_clear(&keys, 0);
+	string_list_remove_duplicates(&keys_uniq, 0);
+	for_each_string_list_item(item, &keys_uniq)
+		puts(item->string);
+	string_list_clear(&keys_uniq, 0);
 }
 
 static enum help_format parse_help_format(const char *format)
@@ -349,8 +382,6 @@
 
 static int git_help_config(const char *var, const char *value, void *cb)
 {
-	if (starts_with(var, "column."))
-		return git_column_config(var, value, "help", &colopts);
 	if (!strcmp(var, "help.format")) {
 		if (!value)
 			return config_error_nonbool(var);
@@ -467,11 +498,14 @@
 	if (!html_path)
 		html_path = to_free = system_path(GIT_HTML_PATH);
 
-	/* Check that we have a git documentation directory. */
+	/*
+	 * Check that the page we're looking for exists.
+	 */
 	if (!strstr(html_path, "://")) {
-		if (stat(mkpath("%s/git.html", html_path), &st)
+		if (stat(mkpath("%s/%s.html", html_path, page), &st)
 		    || !S_ISREG(st.st_mode))
-			die("'%s': not a documentation directory.", html_path);
+			die("'%s/%s.html': documentation file not found.",
+				html_path, page);
 	}
 
 	strbuf_init(page_path, 0);
@@ -541,6 +575,13 @@
 	return cmd;
 }
 
+static void no_extra_argc(int argc)
+{
+	if (argc)
+		usage_msg_opt(_("this option doesn't take any other arguments"),
+			      builtin_help_usage, builtin_help_options);
+}
+
 int cmd_help(int argc, const char **argv, const char *prefix)
 {
 	int nongit;
@@ -551,8 +592,8 @@
 			builtin_help_usage, 0);
 	parsed_help_format = help_format;
 
-	if (show_all) {
-		git_config(git_help_config, NULL);
+	switch (cmd_mode) {
+	case HELP_ACTION_ALL:
 		if (verbose) {
 			setup_pager();
 			list_all_cmds_help();
@@ -560,30 +601,27 @@
 		}
 		printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 		load_command_list("git-", &main_cmds, &other_cmds);
-		list_commands(colopts, &main_cmds, &other_cmds);
-	}
-
-	if (show_config) {
-		int for_human = show_config == 1;
-
-		if (!for_human) {
-			list_config_help(for_human);
-			return 0;
-		}
-		setup_pager();
-		list_config_help(for_human);
-		printf("\n%s\n", _("'git help config' for more information"));
-		return 0;
-	}
-
-	if (show_guides)
-		list_guides_help();
-
-	if (show_all || show_guides) {
+		list_commands(&main_cmds, &other_cmds);
 		printf("%s\n", _(git_more_info_string));
-		/*
-		* We're done. Ignore any remaining args
-		*/
+		break;
+	case HELP_ACTION_GUIDES:
+		no_extra_argc(argc);
+		list_guides_help();
+		printf("%s\n", _(git_more_info_string));
+		return 0;
+	case HELP_ACTION_CONFIG_FOR_COMPLETION:
+		no_extra_argc(argc);
+		list_config_help(SHOW_CONFIG_VARS);
+		return 0;
+	case HELP_ACTION_CONFIG_SECTIONS_FOR_COMPLETION:
+		no_extra_argc(argc);
+		list_config_help(SHOW_CONFIG_SECTIONS);
+		return 0;
+	case HELP_ACTION_CONFIG:
+		no_extra_argc(argc);
+		setup_pager();
+		list_config_help(SHOW_CONFIG_HUMAN);
+		printf("\n%s\n", _("'git help config' for more information"));
 		return 0;
 	}
 
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index f267dce..15ae406 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -122,6 +122,7 @@
 static int do_fsck_object;
 static struct fsck_options fsck_options = FSCK_OPTIONS_MISSING_GITMODULES;
 static int verbose;
+static const char *progress_title;
 static int show_resolving_progress;
 static int show_stat;
 static int check_self_contained_and_connected;
@@ -187,9 +188,7 @@
 	pthread_key_create(&key, NULL);
 	CALLOC_ARRAY(thread_data, nr_threads);
 	for (i = 0; i < nr_threads; i++) {
-		thread_data[i].pack_fd = open(curr_pack, O_RDONLY);
-		if (thread_data[i].pack_fd == -1)
-			die_errno(_("unable to open %s"), curr_pack);
+		thread_data[i].pack_fd = xopen(curr_pack, O_RDONLY);
 	}
 
 	threads_active = 1;
@@ -1153,6 +1152,7 @@
 
 	if (verbose)
 		progress = start_progress(
+				progress_title ? progress_title :
 				from_stdin ? _("Receiving objects") : _("Indexing objects"),
 				nr_objects);
 	for (i = 0; i < nr_objects; i++) {
@@ -1415,7 +1415,7 @@
 
 		if (check_object_signature(the_repository, &d->oid,
 					   data, size,
-					   type_name(type)))
+					   type_name(type), NULL))
 			die(_("local object %s is corrupt"), oid_to_hex(&d->oid));
 
 		/*
@@ -1800,6 +1800,10 @@
 				input_len = sizeof(*hdr);
 			} else if (!strcmp(arg, "-v")) {
 				verbose = 1;
+			} else if (!strcmp(arg, "--progress-title")) {
+				if (progress_title || (i+1) >= argc)
+					usage(index_pack_usage);
+				progress_title = argv[++i];
 			} else if (!strcmp(arg, "--show-resolving-progress")) {
 				show_resolving_progress = 1;
 			} else if (!strcmp(arg, "--report-end-of-input")) {
diff --git a/builtin/log.c b/builtin/log.c
index 3d7717b..f75d87e 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -637,7 +637,7 @@
 	repo_init_revisions(the_repository, &rev, prefix);
 	rev.diff = 1;
 	rev.always_show_header = 1;
-	rev.no_walk = REVISION_WALK_NO_WALK_SORTED;
+	rev.no_walk = 1;
 	rev.diffopt.stat_width = -1; 	/* Scale to real terminal size */
 
 	memset(&opt, 0, sizeof(opt));
diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index 29a26ad..031fef1 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -209,10 +209,8 @@
 			   struct dir_struct *dir, const char *path)
 {
 	struct repository subrepo;
-	const struct submodule *sub = submodule_from_path(superproject,
-							  null_oid(), path);
 
-	if (repo_submodule_init(&subrepo, superproject, sub))
+	if (repo_submodule_init(&subrepo, superproject, path, null_oid()))
 		return;
 
 	if (repo_read_index(&subrepo) < 0)
@@ -614,7 +612,7 @@
 	struct option builtin_ls_files_options[] = {
 		/* Think twice before adding "--nul" synonym to this */
 		OPT_SET_INT('z', NULL, &line_terminator,
-			N_("paths are separated with NUL character"), '\0'),
+			N_("separate paths with the NUL character"), '\0'),
 		OPT_BOOL('t', NULL, &show_tag,
 			N_("identify the file status with tags")),
 		OPT_BOOL('v', NULL, &show_valid_bit,
@@ -651,7 +649,7 @@
 			N_("skip files matching pattern"),
 			PARSE_OPT_NONEG, option_parse_exclude),
 		OPT_CALLBACK_F('X', "exclude-from", &dir, N_("file"),
-			N_("exclude patterns are read from <file>"),
+			N_("read exclude patterns from <file>"),
 			PARSE_OPT_NONEG, option_parse_exclude_from),
 		OPT_STRING(0, "exclude-per-directory", &dir.exclude_per_dir, N_("file"),
 			N_("read additional per-directory exclude patterns in <file>")),
@@ -674,6 +672,7 @@
 			 N_("suppress duplicate entries")),
 		OPT_END()
 	};
+	int ret = 0;
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage_with_options(ls_files_usage, builtin_ls_files_options);
@@ -777,16 +776,13 @@
 	if (show_resolve_undo)
 		show_ru_info(the_repository->index);
 
-	if (ps_matched) {
-		int bad;
-		bad = report_path_error(ps_matched, &pathspec);
-		if (bad)
-			fprintf(stderr, "Did you forget to 'git add'?\n");
-
-		return bad ? 1 : 0;
+	if (ps_matched && report_path_error(ps_matched, &pathspec)) {
+		fprintf(stderr, "Did you forget to 'git add'?\n");
+		ret = 1;
 	}
 
+	string_list_clear(&exclude_list, 0);
 	dir_clear(&dir);
 	free(max_prefix);
-	return 0;
+	return ret;
 }
diff --git a/builtin/ls-remote.c b/builtin/ls-remote.c
index f4fd823..318949c 100644
--- a/builtin/ls-remote.c
+++ b/builtin/ls-remote.c
@@ -7,8 +7,8 @@
 
 static const char * const ls_remote_usage[] = {
 	N_("git ls-remote [--heads] [--tags] [--refs] [--upload-pack=<exec>]\n"
-	   "                     [-q | --quiet] [--exit-code] [--get-url]\n"
-	   "                     [--symref] [<repository> [<refs>...]]"),
+	   "              [-q | --quiet] [--exit-code] [--get-url]\n"
+	   "              [--symref] [<repository> [<refs>...]]"),
 	NULL
 };
 
diff --git a/builtin/merge.c b/builtin/merge.c
index 8949a9c..ea3112e 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -13,6 +13,7 @@
 #include "builtin.h"
 #include "lockfile.h"
 #include "run-command.h"
+#include "hook.h"
 #include "diff.h"
 #include "diff-merges.h"
 #include "refs.h"
@@ -88,9 +89,9 @@
 static int no_verify;
 
 static struct strategy all_strategy[] = {
-	{ "recursive",  DEFAULT_TWOHEAD | NO_TRIVIAL },
+	{ "recursive",  NO_TRIVIAL },
 	{ "octopus",    DEFAULT_OCTOPUS },
-	{ "ort",        NO_TRIVIAL },
+	{ "ort",        DEFAULT_TWOHEAD | NO_TRIVIAL },
 	{ "resolve",    0 },
 	{ "ours",       NO_FAST_FORWARD | NO_TRIVIAL },
 	{ "subtree",    NO_FAST_FORWARD | NO_TRIVIAL },
@@ -469,7 +470,6 @@
 			 * We ignore errors in 'gc --auto', since the
 			 * user should see them.
 			 */
-			close_object_store(the_repository->objects);
 			run_auto_maintenance(verbosity < 0);
 		}
 	}
@@ -681,6 +681,7 @@
 	opts.verbose_update = 1;
 	opts.trivial_merges_only = 1;
 	opts.merge = 1;
+	opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
 	trees[nr_trees] = parse_tree_indirect(common);
 	if (!trees[nr_trees++])
 		return -1;
@@ -849,7 +850,7 @@
 	 * and write it out as a tree.  We must do this before we invoke
 	 * the editor and after we invoke run_status above.
 	 */
-	if (find_hook("pre-merge-commit"))
+	if (hook_exists("pre-merge-commit"))
 		discard_cache();
 	read_cache_from(index_file);
 	strbuf_addbuf(&msg, &merge_msg);
@@ -1276,6 +1277,9 @@
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage_with_options(builtin_merge_usage, builtin_merge_options);
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	/*
 	 * Check if we are _not_ on a detached HEAD, i.e. if there is a
 	 * current branch.
@@ -1368,14 +1372,14 @@
 		 * There is no unmerged entry, don't advise 'git
 		 * add/rm <file>', just 'git commit'.
 		 */
-		if (advice_resolve_conflict)
+		if (advice_enabled(ADVICE_RESOLVE_CONFLICT))
 			die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
 				  "Please, commit your changes before you merge."));
 		else
 			die(_("You have not concluded your merge (MERGE_HEAD exists)."));
 	}
 	if (ref_exists("CHERRY_PICK_HEAD")) {
-		if (advice_resolve_conflict)
+		if (advice_enabled(ADVICE_RESOLVE_CONFLICT))
 			die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
 			    "Please, commit your changes before you merge."));
 		else
@@ -1485,6 +1489,12 @@
 			fast_forward = FF_NO;
 	}
 
+	if (!use_strategies && !pull_twohead &&
+	    remoteheads && !remoteheads->next) {
+		char *default_strategy = getenv("GIT_TEST_MERGE_ALGORITHM");
+		if (default_strategy)
+			append_strategy(get_strategy(default_strategy));
+	}
 	if (!use_strategies) {
 		if (!remoteheads)
 			; /* already up-to-date */
@@ -1568,6 +1578,7 @@
 
 		finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
 		remove_merge_branch_state(the_repository);
+		strbuf_release(&msg);
 		goto done;
 	} else if (!remoteheads->next && common->next)
 		;
@@ -1738,6 +1749,7 @@
 		ret = suggest_conflicts();
 
 done:
+	strbuf_release(&buf);
 	free(branch_to_free);
 	return ret;
 }
diff --git a/builtin/mktag.c b/builtin/mktag.c
index dddcccd..3b2dbbb 100644
--- a/builtin/mktag.c
+++ b/builtin/mktag.c
@@ -62,7 +62,8 @@
 
 	repl = lookup_replace_object(the_repository, tagged_oid);
 	ret = check_object_signature(the_repository, repl,
-				     buffer, size, type_name(*tagged_type));
+				     buffer, size, type_name(*tagged_type),
+				     NULL);
 	free(buffer);
 
 	return ret;
diff --git a/builtin/multi-pack-index.c b/builtin/multi-pack-index.c
index 8ff0dee..075d15d 100644
--- a/builtin/multi-pack-index.c
+++ b/builtin/multi-pack-index.c
@@ -7,7 +7,8 @@
 #include "object-store.h"
 
 #define BUILTIN_MIDX_WRITE_USAGE \
-	N_("git multi-pack-index [<options>] write [--preferred-pack=<pack>]")
+	N_("git multi-pack-index [<options>] write [--preferred-pack=<pack>]" \
+	   "[--refs-snapshot=<path>]")
 
 #define BUILTIN_MIDX_VERIFY_USAGE \
 	N_("git multi-pack-index [<options>] verify")
@@ -45,14 +46,15 @@
 static struct opts_multi_pack_index {
 	const char *object_dir;
 	const char *preferred_pack;
+	const char *refs_snapshot;
 	unsigned long batch_size;
 	unsigned flags;
+	int stdin_packs;
 } opts;
 
 static struct option common_opts[] = {
 	OPT_FILENAME(0, "object-dir", &opts.object_dir,
 	  N_("object directory containing set of packfile and pack-index pairs")),
-	OPT_BIT(0, "progress", &opts.flags, N_("force progress reporting"), MIDX_PROGRESS),
 	OPT_END(),
 };
 
@@ -61,6 +63,33 @@
 	return parse_options_concat(common_opts, prev);
 }
 
+static int git_multi_pack_index_write_config(const char *var, const char *value,
+					     void *cb)
+{
+	if (!strcmp(var, "pack.writebitmaphashcache")) {
+		if (git_config_bool(var, value))
+			opts.flags |= MIDX_WRITE_BITMAP_HASH_CACHE;
+		else
+			opts.flags &= ~MIDX_WRITE_BITMAP_HASH_CACHE;
+	}
+
+	/*
+	 * We should never make a fall-back call to 'git_default_config', since
+	 * this was already called in 'cmd_multi_pack_index()'.
+	 */
+	return 0;
+}
+
+static void read_packs_from_stdin(struct string_list *to)
+{
+	struct strbuf buf = STRBUF_INIT;
+	while (strbuf_getline(&buf, stdin) != EOF)
+		string_list_append(to, buf.buf);
+	string_list_sort(to);
+
+	strbuf_release(&buf);
+}
+
 static int cmd_multi_pack_index_write(int argc, const char **argv)
 {
 	struct option *options;
@@ -68,13 +97,27 @@
 		OPT_STRING(0, "preferred-pack", &opts.preferred_pack,
 			   N_("preferred-pack"),
 			   N_("pack for reuse when computing a multi-pack bitmap")),
+		OPT_BIT(0, "bitmap", &opts.flags, N_("write multi-pack bitmap"),
+			MIDX_WRITE_BITMAP | MIDX_WRITE_REV_INDEX),
+		OPT_BIT(0, "progress", &opts.flags,
+			N_("force progress reporting"), MIDX_PROGRESS),
+		OPT_BOOL(0, "stdin-packs", &opts.stdin_packs,
+			 N_("write multi-pack index containing only given indexes")),
+		OPT_FILENAME(0, "refs-snapshot", &opts.refs_snapshot,
+			     N_("refs snapshot for selecting bitmap commits")),
 		OPT_END(),
 	};
 
+	opts.flags |= MIDX_WRITE_BITMAP_HASH_CACHE;
+
+	git_config(git_multi_pack_index_write_config, NULL);
+
 	options = add_common_options(builtin_multi_pack_index_write_options);
 
 	trace2_cmd_mode(argv[0]);
 
+	if (isatty(2))
+		opts.flags |= MIDX_PROGRESS;
 	argc = parse_options(argc, argv, NULL,
 			     options, builtin_multi_pack_index_write_usage,
 			     PARSE_OPT_KEEP_UNKNOWN);
@@ -84,16 +127,39 @@
 
 	FREE_AND_NULL(options);
 
+	if (opts.stdin_packs) {
+		struct string_list packs = STRING_LIST_INIT_DUP;
+		int ret;
+
+		read_packs_from_stdin(&packs);
+
+		ret = write_midx_file_only(opts.object_dir, &packs,
+					   opts.preferred_pack,
+					   opts.refs_snapshot, opts.flags);
+
+		string_list_clear(&packs, 0);
+
+		return ret;
+
+	}
 	return write_midx_file(opts.object_dir, opts.preferred_pack,
-			       opts.flags);
+			       opts.refs_snapshot, opts.flags);
 }
 
 static int cmd_multi_pack_index_verify(int argc, const char **argv)
 {
-	struct option *options = common_opts;
+	struct option *options;
+	static struct option builtin_multi_pack_index_verify_options[] = {
+		OPT_BIT(0, "progress", &opts.flags,
+			N_("force progress reporting"), MIDX_PROGRESS),
+		OPT_END(),
+	};
+	options = add_common_options(builtin_multi_pack_index_verify_options);
 
 	trace2_cmd_mode(argv[0]);
 
+	if (isatty(2))
+		opts.flags |= MIDX_PROGRESS;
 	argc = parse_options(argc, argv, NULL,
 			     options, builtin_multi_pack_index_verify_usage,
 			     PARSE_OPT_KEEP_UNKNOWN);
@@ -106,10 +172,18 @@
 
 static int cmd_multi_pack_index_expire(int argc, const char **argv)
 {
-	struct option *options = common_opts;
+	struct option *options;
+	static struct option builtin_multi_pack_index_expire_options[] = {
+		OPT_BIT(0, "progress", &opts.flags,
+			N_("force progress reporting"), MIDX_PROGRESS),
+		OPT_END(),
+	};
+	options = add_common_options(builtin_multi_pack_index_expire_options);
 
 	trace2_cmd_mode(argv[0]);
 
+	if (isatty(2))
+		opts.flags |= MIDX_PROGRESS;
 	argc = parse_options(argc, argv, NULL,
 			     options, builtin_multi_pack_index_expire_usage,
 			     PARSE_OPT_KEEP_UNKNOWN);
@@ -126,6 +200,8 @@
 	static struct option builtin_multi_pack_index_repack_options[] = {
 		OPT_MAGNITUDE(0, "batch-size", &opts.batch_size,
 		  N_("during repack, collect pack-files of smaller size into a batch that is larger than this size")),
+		OPT_BIT(0, "progress", &opts.flags,
+		  N_("force progress reporting"), MIDX_PROGRESS),
 		OPT_END(),
 	};
 
@@ -133,6 +209,8 @@
 
 	trace2_cmd_mode(argv[0]);
 
+	if (isatty(2))
+		opts.flags |= MIDX_PROGRESS;
 	argc = parse_options(argc, argv, NULL,
 			     options,
 			     builtin_multi_pack_index_repack_usage,
@@ -154,8 +232,6 @@
 
 	git_config(git_default_config, NULL);
 
-	if (isatty(2))
-		opts.flags |= MIDX_PROGRESS;
 	argc = parse_options(argc, argv, prefix,
 			     builtin_multi_pack_index_options,
 			     builtin_multi_pack_index_usage,
@@ -164,7 +240,7 @@
 	if (!opts.object_dir)
 		opts.object_dir = get_object_directory();
 
-	if (argc == 0)
+	if (!argc)
 		goto usage;
 
 	if (!strcmp(argv[0], "repack"))
@@ -175,10 +251,9 @@
 		return cmd_multi_pack_index_verify(argc, argv);
 	else if (!strcmp(argv[0], "expire"))
 		return cmd_multi_pack_index_expire(argc, argv);
-	else {
-		error(_("unrecognized subcommand: %s"), argv[0]);
+
+	error(_("unrecognized subcommand: %s"), argv[0]);
 usage:
-		usage_with_options(builtin_multi_pack_index_usage,
-				   builtin_multi_pack_index_options);
-	}
+	usage_with_options(builtin_multi_pack_index_usage,
+			   builtin_multi_pack_index_options);
 }
diff --git a/builtin/mv.c b/builtin/mv.c
index c2f96c8..83a465b 100644
--- a/builtin/mv.c
+++ b/builtin/mv.c
@@ -118,21 +118,23 @@
 int cmd_mv(int argc, const char **argv, const char *prefix)
 {
 	int i, flags, gitmodules_modified = 0;
-	int verbose = 0, show_only = 0, force = 0, ignore_errors = 0;
+	int verbose = 0, show_only = 0, force = 0, ignore_errors = 0, ignore_sparse = 0;
 	struct option builtin_mv_options[] = {
 		OPT__VERBOSE(&verbose, N_("be verbose")),
 		OPT__DRY_RUN(&show_only, N_("dry run")),
 		OPT__FORCE(&force, N_("force move/rename even if target exists"),
 			   PARSE_OPT_NOCOMPLETE),
 		OPT_BOOL('k', NULL, &ignore_errors, N_("skip move/rename errors")),
+		OPT_BOOL(0, "sparse", &ignore_sparse, N_("allow updating entries outside of the sparse-checkout cone")),
 		OPT_END(),
 	};
 	const char **source, **destination, **dest_path, **submodule_gitfile;
-	enum update_mode { BOTH = 0, WORKING_DIRECTORY, INDEX } *modes;
+	enum update_mode { BOTH = 0, WORKING_DIRECTORY, INDEX, SPARSE } *modes;
 	struct stat st;
 	struct string_list src_for_dst = STRING_LIST_INIT_NODUP;
 	struct lock_file lock_file = LOCK_INIT;
 	struct cache_entry *ce;
+	struct string_list only_match_skip_worktree = STRING_LIST_INIT_NODUP;
 
 	git_config(git_default_config, NULL);
 
@@ -176,14 +178,17 @@
 		const char *src = source[i], *dst = destination[i];
 		int length, src_is_dir;
 		const char *bad = NULL;
+		int skip_sparse = 0;
 
 		if (show_only)
 			printf(_("Checking rename of '%s' to '%s'\n"), src, dst);
 
 		length = strlen(src);
-		if (lstat(src, &st) < 0)
-			bad = _("bad source");
-		else if (!strncmp(src, dst, length) &&
+		if (lstat(src, &st) < 0) {
+			/* only error if existence is expected. */
+			if (modes[i] != SPARSE)
+				bad = _("bad source");
+		} else 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))
@@ -212,11 +217,12 @@
 				dst_len = strlen(dst);
 
 				for (j = 0; j < last - first; j++) {
-					const char *path = active_cache[first + j]->name;
+					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] = INDEX;
+					modes[argc + j] = ce_skip_worktree(ce) ? SPARSE : INDEX;
 					submodule_gitfile[argc + j] = NULL;
 				}
 				argc += last - first;
@@ -244,14 +250,36 @@
 			bad = _("multiple sources for the same target");
 		else if (is_dir_sep(dst[strlen(dst) - 1]))
 			bad = _("destination directory does not exist");
-		else
+		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);
+		}
 
 		if (!bad)
 			continue;
 		if (!ignore_errors)
 			die(_("%s, source=%s, destination=%s"),
 			     bad, src, dst);
+remove_entry:
 		if (--argc > 0) {
 			int n = argc - i;
 			memmove(source + i, source + i + 1,
@@ -266,6 +294,12 @@
 		}
 	}
 
+	if (only_match_skip_worktree.nr) {
+		advise_on_updating_sparse_paths(&only_match_skip_worktree);
+		if (!ignore_errors)
+			return 1;
+	}
+
 	for (i = 0; i < argc; i++) {
 		const char *src = source[i], *dst = destination[i];
 		enum update_mode mode = modes[i];
@@ -274,7 +308,7 @@
 			printf(_("Renaming %s to %s\n"), src, dst);
 		if (show_only)
 			continue;
-		if (mode != INDEX && rename(src, dst) < 0) {
+		if (mode != INDEX && mode != SPARSE && rename(src, dst) < 0) {
 			if (ignore_errors)
 				continue;
 			die_errno(_("renaming '%s' failed"), src);
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index a01767a..1a3dd44 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1124,6 +1124,11 @@
 				break;
 
 			offset += ewah_bit_ctz64(word >> offset);
+			/*
+			 * Can use bit positions directly, even for MIDX
+			 * bitmaps. See comment in try_partial_reuse()
+			 * for why.
+			 */
 			write_reused_pack_one(pos + offset, f, &w_curs);
 			display_progress(progress_state, ++written);
 		}
@@ -1259,7 +1264,8 @@
 
 				bitmap_writer_show_progress(progress);
 				bitmap_writer_select_commits(indexed_commits, indexed_commits_nr, -1);
-				bitmap_writer_build(&to_pack);
+				if (bitmap_writer_build(&to_pack) < 0)
+					die(_("failed to write bitmap index"));
 				bitmap_writer_finish(written_list, nr_written,
 						     tmpname.buf, write_bitmap_options);
 				write_bitmap_index = 0;
@@ -3412,13 +3418,9 @@
 	}
 }
 
-/* Remember to update object flag allocation in object.h */
-#define OBJECT_ADDED (1u<<20)
-
 static void show_commit(struct commit *commit, void *data)
 {
 	add_object_entry(&commit->object.oid, OBJ_COMMIT, NULL, 0);
-	commit->object.flags |= OBJECT_ADDED;
 
 	if (write_bitmap_index)
 		index_commit_for_bitmap(commit);
@@ -3431,7 +3433,6 @@
 {
 	add_preferred_base_object(name);
 	add_object_entry(&obj->oid, obj->type, name, 0);
-	obj->flags |= OBJECT_ADDED;
 
 	if (use_delta_islands) {
 		const char *p;
@@ -3512,79 +3513,23 @@
 	add_preferred_base(&commit->object.oid);
 }
 
-struct in_pack_object {
-	off_t offset;
-	struct object *object;
-};
-
-struct in_pack {
-	unsigned int alloc;
-	unsigned int nr;
-	struct in_pack_object *array;
-};
-
-static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
+static int add_object_in_unpacked_pack(const struct object_id *oid,
+				       struct packed_git *pack,
+				       uint32_t pos,
+				       void *_data)
 {
-	in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->oid.hash, p);
-	in_pack->array[in_pack->nr].object = object;
-	in_pack->nr++;
-}
-
-/*
- * Compare the objects in the offset order, in order to emulate the
- * "git rev-list --objects" output that produced the pack originally.
- */
-static int ofscmp(const void *a_, const void *b_)
-{
-	struct in_pack_object *a = (struct in_pack_object *)a_;
-	struct in_pack_object *b = (struct in_pack_object *)b_;
-
-	if (a->offset < b->offset)
-		return -1;
-	else if (a->offset > b->offset)
-		return 1;
-	else
-		return oidcmp(&a->object->oid, &b->object->oid);
+	add_object_entry(oid, OBJ_NONE, "", 0);
+	return 0;
 }
 
 static void add_objects_in_unpacked_packs(void)
 {
-	struct packed_git *p;
-	struct in_pack in_pack;
-	uint32_t i;
-
-	memset(&in_pack, 0, sizeof(in_pack));
-
-	for (p = get_all_packs(the_repository); p; p = p->next) {
-		struct object_id oid;
-		struct object *o;
-
-		if (!p->pack_local || p->pack_keep || p->pack_keep_in_core)
-			continue;
-		if (open_pack_index(p))
-			die(_("cannot open pack index"));
-
-		ALLOC_GROW(in_pack.array,
-			   in_pack.nr + p->num_objects,
-			   in_pack.alloc);
-
-		for (i = 0; i < p->num_objects; i++) {
-			nth_packed_object_id(&oid, p, i);
-			o = lookup_unknown_object(the_repository, &oid);
-			if (!(o->flags & OBJECT_ADDED))
-				mark_in_pack_object(o, p, &in_pack);
-			o->flags |= OBJECT_ADDED;
-		}
-	}
-
-	if (in_pack.nr) {
-		QSORT(in_pack.array, in_pack.nr, ofscmp);
-		for (i = 0; i < in_pack.nr; i++) {
-			struct object *o = in_pack.array[i].object;
-			add_object_entry(&o->oid, o->type, "", 0);
-		}
-	}
-	free(in_pack.array);
+	if (for_each_packed_object(add_object_in_unpacked_pack, NULL,
+				   FOR_EACH_OBJECT_PACK_ORDER |
+				   FOR_EACH_OBJECT_LOCAL_ONLY |
+				   FOR_EACH_OBJECT_SKIP_IN_CORE_KEPT_PACKS |
+				   FOR_EACH_OBJECT_SKIP_ON_DISK_KEPT_PACKS))
+		die(_("cannot open pack index"));
 }
 
 static int add_loose_object(const struct object_id *oid, const char *path,
diff --git a/builtin/prune.c b/builtin/prune.c
index 02c6ab7..485c9a3 100644
--- a/builtin/prune.c
+++ b/builtin/prune.c
@@ -143,7 +143,6 @@
 	expire = TIME_MAX;
 	save_commit_buffer = 0;
 	read_replace_refs = 0;
-	ref_paranoia = 1;
 	repo_init_revisions(the_repository, &revs, prefix);
 
 	argc = parse_options(argc, argv, prefix, options, prune_usage, 0);
diff --git a/builtin/pull.c b/builtin/pull.c
index b311ea6..ae9f5bd 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -26,13 +26,13 @@
 #include "wt-status.h"
 #include "commit-reach.h"
 #include "sequencer.h"
+#include "packfile.h"
 
 /**
  * Parses the value of --rebase. If value is a false value, returns
  * REBASE_FALSE. If value is a true value, returns REBASE_TRUE. If value is
- * "merges", returns REBASE_MERGES. If value is "preserve", returns
- * REBASE_PRESERVE. If value is a invalid value, dies with a fatal error if
- * fatal is true, otherwise returns REBASE_INVALID.
+ * "merges", returns REBASE_MERGES. If value is a invalid value, dies with
+ * a fatal error if fatal is true, otherwise returns REBASE_INVALID.
  */
 static enum rebase_type parse_config_rebase(const char *key, const char *value,
 		int fatal)
@@ -126,7 +126,7 @@
 	/* Options passed to git-merge or git-rebase */
 	OPT_GROUP(N_("Options related to merging")),
 	OPT_CALLBACK_F('r', "rebase", &opt_rebase,
-		"(false|true|merges|preserve|interactive)",
+		"(false|true|merges|interactive)",
 		N_("incorporate changes by rebasing rather than merging"),
 		PARSE_OPT_OPTARG, parse_opt_rebase),
 	OPT_PASSTHRU('n', NULL, &opt_diffstat, NULL,
@@ -577,7 +577,7 @@
 		strvec_pushv(&args, refspecs);
 	} else if (*refspecs)
 		BUG("refspecs without repo?");
-	ret = run_command_v_opt(args.v, RUN_GIT_CMD);
+	ret = run_command_v_opt(args.v, RUN_GIT_CMD | RUN_CLOSE_OBJECT_STORE);
 	strvec_clear(&args);
 	return ret;
 }
@@ -883,8 +883,6 @@
 	/* Options passed to git-rebase */
 	if (opt_rebase == REBASE_MERGES)
 		strvec_push(&args, "--rebase-merges");
-	else if (opt_rebase == REBASE_PRESERVE)
-		strvec_push(&args, "--preserve-merges");
 	else if (opt_rebase == REBASE_INTERACTIVE)
 		strvec_push(&args, "--interactive");
 	if (opt_diffstat)
diff --git a/builtin/push.c b/builtin/push.c
index e8b10a9..4b026ce 100644
--- a/builtin/push.c
+++ b/builtin/push.c
@@ -289,42 +289,42 @@
 
 static void advise_pull_before_push(void)
 {
-	if (!advice_push_non_ff_current || !advice_push_update_rejected)
+	if (!advice_enabled(ADVICE_PUSH_NON_FF_CURRENT) || !advice_enabled(ADVICE_PUSH_UPDATE_REJECTED))
 		return;
 	advise(_(message_advice_pull_before_push));
 }
 
 static void advise_checkout_pull_push(void)
 {
-	if (!advice_push_non_ff_matching || !advice_push_update_rejected)
+	if (!advice_enabled(ADVICE_PUSH_NON_FF_MATCHING) || !advice_enabled(ADVICE_PUSH_UPDATE_REJECTED))
 		return;
 	advise(_(message_advice_checkout_pull_push));
 }
 
 static void advise_ref_already_exists(void)
 {
-	if (!advice_push_already_exists || !advice_push_update_rejected)
+	if (!advice_enabled(ADVICE_PUSH_ALREADY_EXISTS) || !advice_enabled(ADVICE_PUSH_UPDATE_REJECTED))
 		return;
 	advise(_(message_advice_ref_already_exists));
 }
 
 static void advise_ref_fetch_first(void)
 {
-	if (!advice_push_fetch_first || !advice_push_update_rejected)
+	if (!advice_enabled(ADVICE_PUSH_FETCH_FIRST) || !advice_enabled(ADVICE_PUSH_UPDATE_REJECTED))
 		return;
 	advise(_(message_advice_ref_fetch_first));
 }
 
 static void advise_ref_needs_force(void)
 {
-	if (!advice_push_needs_force || !advice_push_update_rejected)
+	if (!advice_enabled(ADVICE_PUSH_NEEDS_FORCE) || !advice_enabled(ADVICE_PUSH_UPDATE_REJECTED))
 		return;
 	advise(_(message_advice_ref_needs_force));
 }
 
 static void advise_ref_needs_update(void)
 {
-	if (!advice_push_ref_needs_update || !advice_push_update_rejected)
+	if (!advice_enabled(ADVICE_PUSH_REF_NEEDS_UPDATE) || !advice_enabled(ADVICE_PUSH_UPDATE_REJECTED))
 		return;
 	advise(_(message_advice_ref_needs_update));
 }
diff --git a/builtin/read-tree.c b/builtin/read-tree.c
index 485e7b0..2109c4c 100644
--- a/builtin/read-tree.c
+++ b/builtin/read-tree.c
@@ -38,7 +38,7 @@
 }
 
 static const char * const read_tree_usage[] = {
-	N_("git read-tree [(-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>) [-u [--exclude-per-directory=<gitignore>] | -i]] [--no-sparse-checkout] [--index-output=<file>] (--empty | <tree-ish1> [<tree-ish2> [<tree-ish3>]])"),
+	N_("git read-tree [(-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>) [-u | -i]] [--no-sparse-checkout] [--index-output=<file>] (--empty | <tree-ish1> [<tree-ish2> [<tree-ish3>]])"),
 	NULL
 };
 
@@ -53,24 +53,16 @@
 static int exclude_per_directory_cb(const struct option *opt, const char *arg,
 				    int unset)
 {
-	struct dir_struct *dir;
 	struct unpack_trees_options *opts;
 
 	BUG_ON_OPT_NEG(unset);
 
 	opts = (struct unpack_trees_options *)opt->value;
 
-	if (opts->dir)
-		die("more than one --exclude-per-directory given.");
-
-	dir = xcalloc(1, sizeof(*opts->dir));
-	dir->flags |= DIR_SHOW_IGNORED;
-	dir->exclude_per_dir = arg;
-	opts->dir = dir;
-	/* We do not need to nor want to do read-directory
-	 * here; we are merely interested in reusing the
-	 * per directory ignore stack mechanism.
-	 */
+	if (!opts->update)
+		die("--exclude-per-directory is meaningless unless -u");
+	if (strcmp(arg, ".gitignore"))
+		die("--exclude-per-directory argument must be .gitignore");
 	return 0;
 }
 
@@ -174,6 +166,9 @@
 	if (1 < opts.merge + opts.reset + prefix_set)
 		die("Which one? -m, --reset, or --prefix?");
 
+	if (opts.reset)
+		opts.reset = UNPACK_RESET_OVERWRITE_UNTRACKED;
+
 	/*
 	 * NEEDSWORK
 	 *
@@ -209,8 +204,9 @@
 	if ((opts.update || opts.index_only) && !opts.merge)
 		die("%s is meaningless without -m, --reset, or --prefix",
 		    opts.update ? "-u" : "-i");
-	if ((opts.dir && !opts.update))
-		die("--exclude-per-directory is meaningless unless -u");
+	if (opts.update && !opts.reset)
+		opts.preserve_ignored = 0;
+	/* otherwise, opts.preserve_ignored is irrelevant */
 	if (opts.merge && !opts.index_only)
 		setup_work_tree();
 
diff --git a/builtin/rebase.c b/builtin/rebase.c
index 66a0a0f..34b4744 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -48,8 +48,7 @@
 enum rebase_type {
 	REBASE_UNSPECIFIED = -1,
 	REBASE_APPLY,
-	REBASE_MERGE,
-	REBASE_PRESERVE_MERGES
+	REBASE_MERGE
 };
 
 enum empty_type {
@@ -163,12 +162,7 @@
 	ACTION_ABORT,
 	ACTION_QUIT,
 	ACTION_EDIT_TODO,
-	ACTION_SHOW_CURRENT_PATCH,
-	ACTION_SHORTEN_OIDS,
-	ACTION_EXPAND_OIDS,
-	ACTION_CHECK_TODO_LIST,
-	ACTION_REARRANGE_SQUASH,
-	ACTION_ADD_EXEC
+	ACTION_SHOW_CURRENT_PATCH
 };
 
 static const char *action_names[] = { "undefined",
@@ -179,81 +173,6 @@
 				      "edit_todo",
 				      "show_current_patch" };
 
-static int add_exec_commands(struct string_list *commands)
-{
-	const char *todo_file = rebase_path_todo();
-	struct todo_list todo_list = TODO_LIST_INIT;
-	int res;
-
-	if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
-		return error_errno(_("could not read '%s'."), todo_file);
-
-	if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
-					&todo_list)) {
-		todo_list_release(&todo_list);
-		return error(_("unusable todo list: '%s'"), todo_file);
-	}
-
-	todo_list_add_exec_commands(&todo_list, commands);
-	res = todo_list_write_to_file(the_repository, &todo_list,
-				      todo_file, NULL, NULL, -1, 0);
-	todo_list_release(&todo_list);
-
-	if (res)
-		return error_errno(_("could not write '%s'."), todo_file);
-	return 0;
-}
-
-static int rearrange_squash_in_todo_file(void)
-{
-	const char *todo_file = rebase_path_todo();
-	struct todo_list todo_list = TODO_LIST_INIT;
-	int res = 0;
-
-	if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
-		return error_errno(_("could not read '%s'."), todo_file);
-	if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
-					&todo_list)) {
-		todo_list_release(&todo_list);
-		return error(_("unusable todo list: '%s'"), todo_file);
-	}
-
-	res = todo_list_rearrange_squash(&todo_list);
-	if (!res)
-		res = todo_list_write_to_file(the_repository, &todo_list,
-					      todo_file, NULL, NULL, -1, 0);
-
-	todo_list_release(&todo_list);
-
-	if (res)
-		return error_errno(_("could not write '%s'."), todo_file);
-	return 0;
-}
-
-static int transform_todo_file(unsigned flags)
-{
-	const char *todo_file = rebase_path_todo();
-	struct todo_list todo_list = TODO_LIST_INIT;
-	int res;
-
-	if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
-		return error_errno(_("could not read '%s'."), todo_file);
-
-	if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf,
-					&todo_list)) {
-		todo_list_release(&todo_list);
-		return error(_("unusable todo list: '%s'"), todo_file);
-	}
-
-	res = todo_list_write_to_file(the_repository, &todo_list, todo_file,
-				      NULL, NULL, -1, flags);
-	todo_list_release(&todo_list);
-
-	if (res)
-		return error_errno(_("could not write '%s'."), todo_file);
-	return 0;
-}
-
 static int edit_todo_file(unsigned flags)
 {
 	const char *todo_file = rebase_path_todo();
@@ -403,8 +322,8 @@
 	flags |= opts->rebase_merges ? TODO_LIST_REBASE_MERGES : 0;
 	flags |= opts->rebase_cousins > 0 ? TODO_LIST_REBASE_COUSINS : 0;
 	flags |= opts->root_with_onto ? TODO_LIST_ROOT_WITH_ONTO : 0;
-	flags |= command == ACTION_SHORTEN_OIDS ? TODO_LIST_SHORTEN_IDS : 0;
 	flags |= opts->reapply_cherry_picks ? TODO_LIST_REAPPLY_CHERRY_PICKS : 0;
+	flags |= opts->flags & REBASE_NO_QUIET ? TODO_LIST_WARN_SKIPPED_CHERRY_PICKS : 0;
 
 	switch (command) {
 	case ACTION_NONE: {
@@ -438,24 +357,6 @@
 
 		break;
 	}
-	case ACTION_SHORTEN_OIDS:
-	case ACTION_EXPAND_OIDS:
-		ret = transform_todo_file(flags);
-		break;
-	case ACTION_CHECK_TODO_LIST:
-		ret = check_todo_list_from_file(the_repository);
-		break;
-	case ACTION_REARRANGE_SQUASH:
-		ret = rearrange_squash_in_todo_file();
-		break;
-	case ACTION_ADD_EXEC: {
-		struct string_list commands = STRING_LIST_INIT_DUP;
-
-		split_exec_commands(opts->cmd, &commands);
-		ret = add_exec_commands(&commands);
-		string_list_clear(&commands, 0);
-		break;
-	}
 	default:
 		BUG("invalid command '%d'", command);
 	}
@@ -477,102 +378,9 @@
 	return 0;
 }
 
-static const char * const builtin_rebase_interactive_usage[] = {
-	N_("git rebase--interactive [<options>]"),
-	NULL
-};
-
-int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
-{
-	struct rebase_options opts = REBASE_OPTIONS_INIT;
-	struct object_id squash_onto = *null_oid();
-	enum action command = ACTION_NONE;
-	struct option options[] = {
-		OPT_NEGBIT(0, "ff", &opts.flags, N_("allow fast-forward"),
-			   REBASE_FORCE),
-		OPT_CALLBACK_F('k', "keep-empty", &options, NULL,
-			N_("keep commits which start empty"),
-			PARSE_OPT_NOARG | PARSE_OPT_HIDDEN,
-			parse_opt_keep_empty),
-		OPT_BOOL_F(0, "allow-empty-message", &opts.allow_empty_message,
-			   N_("allow commits with empty messages"),
-			   PARSE_OPT_HIDDEN),
-		OPT_BOOL(0, "rebase-merges", &opts.rebase_merges, N_("rebase merge commits")),
-		OPT_BOOL(0, "rebase-cousins", &opts.rebase_cousins,
-			 N_("keep original branch points of cousins")),
-		OPT_BOOL(0, "autosquash", &opts.autosquash,
-			 N_("move commits that begin with squash!/fixup!")),
-		OPT_BOOL(0, "signoff", &opts.signoff, N_("sign commits")),
-		OPT_BIT('v', "verbose", &opts.flags,
-			N_("display a diffstat of what changed upstream"),
-			REBASE_NO_QUIET | REBASE_VERBOSE | REBASE_DIFFSTAT),
-		OPT_CMDMODE(0, "continue", &command, N_("continue rebase"),
-			    ACTION_CONTINUE),
-		OPT_CMDMODE(0, "skip", &command, N_("skip commit"), ACTION_SKIP),
-		OPT_CMDMODE(0, "edit-todo", &command, N_("edit the todo list"),
-			    ACTION_EDIT_TODO),
-		OPT_CMDMODE(0, "show-current-patch", &command, N_("show the current patch"),
-			    ACTION_SHOW_CURRENT_PATCH),
-		OPT_CMDMODE(0, "shorten-ids", &command,
-			N_("shorten commit ids in the todo list"), ACTION_SHORTEN_OIDS),
-		OPT_CMDMODE(0, "expand-ids", &command,
-			N_("expand commit ids in the todo list"), ACTION_EXPAND_OIDS),
-		OPT_CMDMODE(0, "check-todo-list", &command,
-			N_("check the todo list"), ACTION_CHECK_TODO_LIST),
-		OPT_CMDMODE(0, "rearrange-squash", &command,
-			N_("rearrange fixup/squash lines"), ACTION_REARRANGE_SQUASH),
-		OPT_CMDMODE(0, "add-exec-commands", &command,
-			N_("insert exec commands in todo list"), ACTION_ADD_EXEC),
-		{ OPTION_CALLBACK, 0, "onto", &opts.onto, N_("onto"), N_("onto"),
-		  PARSE_OPT_NONEG, parse_opt_commit, 0 },
-		{ OPTION_CALLBACK, 0, "restrict-revision", &opts.restrict_revision,
-		  N_("restrict-revision"), N_("restrict revision"),
-		  PARSE_OPT_NONEG, parse_opt_commit, 0 },
-		{ OPTION_CALLBACK, 0, "squash-onto", &squash_onto, N_("squash-onto"),
-		  N_("squash onto"), PARSE_OPT_NONEG, parse_opt_object_id, 0 },
-		{ OPTION_CALLBACK, 0, "upstream", &opts.upstream, N_("upstream"),
-		  N_("the upstream commit"), PARSE_OPT_NONEG, parse_opt_commit,
-		  0 },
-		OPT_STRING(0, "head-name", &opts.head_name, N_("head-name"), N_("head name")),
-		{ OPTION_STRING, 'S', "gpg-sign", &opts.gpg_sign_opt, N_("key-id"),
-			N_("GPG-sign commits"),
-			PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
-		OPT_STRING(0, "strategy", &opts.strategy, N_("strategy"),
-			   N_("rebase strategy")),
-		OPT_STRING(0, "strategy-opts", &opts.strategy_opts, N_("strategy-opts"),
-			   N_("strategy options")),
-		OPT_STRING(0, "switch-to", &opts.switch_to, N_("switch-to"),
-			   N_("the branch or commit to checkout")),
-		OPT_STRING(0, "onto-name", &opts.onto_name, N_("onto-name"), N_("onto name")),
-		OPT_STRING(0, "cmd", &opts.cmd, N_("cmd"), N_("the command to run")),
-		OPT_RERERE_AUTOUPDATE(&opts.allow_rerere_autoupdate),
-		OPT_BOOL(0, "reschedule-failed-exec", &opts.reschedule_failed_exec,
-			 N_("automatically re-schedule any `exec` that fails")),
-		OPT_END()
-	};
-
-	opts.rebase_cousins = -1;
-
-	if (argc == 1)
-		usage_with_options(builtin_rebase_interactive_usage, options);
-
-	argc = parse_options(argc, argv, prefix, options,
-			builtin_rebase_interactive_usage, PARSE_OPT_KEEP_ARGV0);
-
-	if (!is_null_oid(&squash_onto))
-		opts.squash_onto = &squash_onto;
-
-	if (opts.rebase_cousins >= 0 && !opts.rebase_merges)
-		warning(_("--[no-]rebase-cousins has no effect without "
-			  "--rebase-merges"));
-
-	return !!run_sequencer_rebase(&opts, command);
-}
-
 static int is_merge(struct rebase_options *opts)
 {
-	return opts->type == REBASE_MERGE ||
-		opts->type == REBASE_PRESERVE_MERGES;
+	return opts->type == REBASE_MERGE;
 }
 
 static void imply_merge(struct rebase_options *opts, const char *option)
@@ -582,7 +390,6 @@
 		die(_("%s requires the merge backend"), option);
 		break;
 	case REBASE_MERGE:
-	case REBASE_PRESERVE_MERGES:
 		break;
 	default:
 		opts->type = REBASE_MERGE; /* implied */
@@ -740,7 +547,6 @@
 	delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 	unlink(git_path_auto_merge(the_repository));
 	apply_autostash(state_dir_path("autostash", opts));
-	close_object_store(the_repository->objects);
 	/*
 	 * We ignore errors in 'git maintenance run --auto', since the
 	 * user should see them.
@@ -762,28 +568,6 @@
 	return ret;
 }
 
-static struct commit *peel_committish(const char *name)
-{
-	struct object *obj;
-	struct object_id oid;
-
-	if (get_oid(name, &oid))
-		return NULL;
-	obj = parse_object(the_repository, &oid);
-	return (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
-}
-
-static void add_var(struct strbuf *buf, const char *name, const char *value)
-{
-	if (!value)
-		strbuf_addf(buf, "unset %s; ", name);
-	else {
-		strbuf_addf(buf, "%s=", name);
-		sq_quote_buf(buf, value);
-		strbuf_addstr(buf, "; ");
-	}
-}
-
 static int move_to_original_branch(struct rebase_options *opts)
 {
 	struct strbuf orig_head_reflog = STRBUF_INIT, head_reflog = STRBUF_INIT;
@@ -940,10 +724,7 @@
 
 static int run_specific_rebase(struct rebase_options *opts, enum action action)
 {
-	const char *argv[] = { NULL, NULL };
-	struct strbuf script_snippet = STRBUF_INIT, buf = STRBUF_INIT;
 	int status;
-	const char *backend, *backend_func;
 
 	if (opts->type == REBASE_MERGE) {
 		/* Run sequencer-based rebase */
@@ -960,87 +741,11 @@
 		}
 
 		status = run_sequencer_rebase(opts, action);
-		goto finished_rebase;
-	}
-
-	if (opts->type == REBASE_APPLY) {
+	} else if (opts->type == REBASE_APPLY)
 		status = run_am(opts);
-		goto finished_rebase;
-	}
-
-	add_var(&script_snippet, "GIT_DIR", absolute_path(get_git_dir()));
-	add_var(&script_snippet, "state_dir", opts->state_dir);
-
-	add_var(&script_snippet, "upstream_name", opts->upstream_name);
-	add_var(&script_snippet, "upstream", opts->upstream ?
-		oid_to_hex(&opts->upstream->object.oid) : NULL);
-	add_var(&script_snippet, "head_name",
-		opts->head_name ? opts->head_name : "detached HEAD");
-	add_var(&script_snippet, "orig_head", oid_to_hex(&opts->orig_head));
-	add_var(&script_snippet, "onto", opts->onto ?
-		oid_to_hex(&opts->onto->object.oid) : NULL);
-	add_var(&script_snippet, "onto_name", opts->onto_name);
-	add_var(&script_snippet, "revisions", opts->revisions);
-	add_var(&script_snippet, "restrict_revision", opts->restrict_revision ?
-		oid_to_hex(&opts->restrict_revision->object.oid) : NULL);
-	sq_quote_argv_pretty(&buf, opts->git_am_opts.v);
-	add_var(&script_snippet, "git_am_opt", buf.buf);
-	strbuf_release(&buf);
-	add_var(&script_snippet, "verbose",
-		opts->flags & REBASE_VERBOSE ? "t" : "");
-	add_var(&script_snippet, "diffstat",
-		opts->flags & REBASE_DIFFSTAT ? "t" : "");
-	add_var(&script_snippet, "force_rebase",
-		opts->flags & REBASE_FORCE ? "t" : "");
-	if (opts->switch_to)
-		add_var(&script_snippet, "switch_to", opts->switch_to);
-	add_var(&script_snippet, "action", opts->action ? opts->action : "");
-	add_var(&script_snippet, "signoff", opts->signoff ? "--signoff" : "");
-	add_var(&script_snippet, "allow_rerere_autoupdate",
-		opts->allow_rerere_autoupdate ?
-			opts->allow_rerere_autoupdate == RERERE_AUTOUPDATE ?
-			"--rerere-autoupdate" : "--no-rerere-autoupdate" : "");
-	add_var(&script_snippet, "keep_empty", opts->keep_empty ? "yes" : "");
-	add_var(&script_snippet, "autosquash", opts->autosquash ? "t" : "");
-	add_var(&script_snippet, "gpg_sign_opt", opts->gpg_sign_opt);
-	add_var(&script_snippet, "cmd", opts->cmd);
-	add_var(&script_snippet, "allow_empty_message",
-		opts->allow_empty_message ?  "--allow-empty-message" : "");
-	add_var(&script_snippet, "rebase_merges",
-		opts->rebase_merges ? "t" : "");
-	add_var(&script_snippet, "rebase_cousins",
-		opts->rebase_cousins ? "t" : "");
-	add_var(&script_snippet, "strategy", opts->strategy);
-	add_var(&script_snippet, "strategy_opts", opts->strategy_opts);
-	add_var(&script_snippet, "rebase_root", opts->root ? "t" : "");
-	add_var(&script_snippet, "squash_onto",
-		opts->squash_onto ? oid_to_hex(opts->squash_onto) : "");
-	add_var(&script_snippet, "git_format_patch_opt",
-		opts->git_format_patch_opt.buf);
-
-	if (is_merge(opts) &&
-	    !(opts->flags & REBASE_INTERACTIVE_EXPLICIT)) {
-		strbuf_addstr(&script_snippet,
-			      "GIT_SEQUENCE_EDITOR=:; export GIT_SEQUENCE_EDITOR; ");
-		opts->autosquash = 0;
-	}
-
-	switch (opts->type) {
-	case REBASE_PRESERVE_MERGES:
-		backend = "git-rebase--preserve-merges";
-		backend_func = "git_rebase__preserve_merges";
-		break;
-	default:
+	else
 		BUG("Unhandled rebase type %d", opts->type);
-		break;
-	}
 
-	strbuf_addf(&script_snippet,
-		    ". git-sh-setup && . %s && %s", backend, backend_func);
-	argv[0] = script_snippet.buf;
-
-	status = run_command_v_opt(argv, RUN_USING_SHELL);
-finished_rebase:
 	if (opts->dont_finish_rebase)
 		; /* do nothing */
 	else if (opts->type == REBASE_MERGE)
@@ -1058,8 +763,6 @@
 		die("Nothing to do");
 	}
 
-	strbuf_release(&script_snippet);
-
 	return status ? -1 : 0;
 }
 
@@ -1195,7 +898,7 @@
 	return 0;
 }
 
-/* -i followed by -p is still explicitly interactive, but -p alone is not */
+/* -i followed by -r is still explicitly interactive, but -r alone is not */
 static int parse_opt_interactive(const struct option *opt, const char *arg,
 				 int unset)
 {
@@ -1313,6 +1016,7 @@
 	char *squash_onto_name = NULL;
 	int reschedule_failed_exec = -1;
 	int allow_preemptive_ff = 1;
+	int preserve_merges_selected = 0;
 	struct option builtin_rebase_options[] = {
 		OPT_STRING(0, "onto", &options.onto_name,
 			   N_("revision"),
@@ -1377,10 +1081,10 @@
 			N_("let the user edit the list of commits to rebase"),
 			PARSE_OPT_NOARG | PARSE_OPT_NONEG,
 			parse_opt_interactive),
-		OPT_SET_INT_F('p', "preserve-merges", &options.type,
+		OPT_SET_INT_F('p', "preserve-merges", &preserve_merges_selected,
 			      N_("(DEPRECATED) try to recreate merges instead of "
 				 "ignoring them"),
-			      REBASE_PRESERVE_MERGES, PARSE_OPT_HIDDEN),
+			      1, PARSE_OPT_HIDDEN),
 		OPT_RERERE_AUTOUPDATE(&options.allow_rerere_autoupdate),
 		OPT_CALLBACK_F(0, "empty", &options, "{drop,keep,ask}",
 			       N_("how to handle commits that become empty"),
@@ -1430,6 +1134,9 @@
 		usage_with_options(builtin_rebase_usage,
 				   builtin_rebase_options);
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	options.allow_empty_message = 1;
 	git_config(rebase_config, &options);
 	/* options.gpg_sign_opt will be either "-S" or NULL */
@@ -1448,8 +1155,7 @@
 		strbuf_reset(&buf);
 		strbuf_addf(&buf, "%s/rewritten", merge_dir());
 		if (is_directory(buf.buf)) {
-			options.type = REBASE_PRESERVE_MERGES;
-			options.flags |= REBASE_INTERACTIVE_EXPLICIT;
+			die("`rebase -p` is no longer supported");
 		} else {
 			strbuf_reset(&buf);
 			strbuf_addf(&buf, "%s/interactive", merge_dir());
@@ -1470,6 +1176,9 @@
 			     builtin_rebase_options,
 			     builtin_rebase_usage, 0);
 
+	if (preserve_merges_selected)
+		die(_("--preserve-merges was replaced by --rebase-merges"));
+
 	if (action != ACTION_NONE && total_argc != 2) {
 		usage_with_options(builtin_rebase_usage,
 				   builtin_rebase_options);
@@ -1479,10 +1188,6 @@
 		usage_with_options(builtin_rebase_usage,
 				   builtin_rebase_options);
 
-	if (options.type == REBASE_PRESERVE_MERGES)
-		warning(_("git rebase --preserve-merges is deprecated. "
-			  "Use --rebase-merges instead."));
-
 	if (keep_base) {
 		if (options.onto_name)
 			die(_("cannot combine '--keep-base' with '--onto'"));
@@ -1574,7 +1279,7 @@
 			die(_("could not move back to %s"),
 			    oid_to_hex(&options.orig_head));
 		remove_branch_state(the_repository, 0);
-		ret = !!finish_rebase(&options);
+		ret = finish_rebase(&options);
 		goto cleanup;
 	}
 	case ACTION_QUIT: {
@@ -1583,11 +1288,11 @@
 			struct replay_opts replay = REPLAY_OPTS_INIT;
 
 			replay.action = REPLAY_INTERACTIVE_REBASE;
-			ret = !!sequencer_remove_state(&replay);
+			ret = sequencer_remove_state(&replay);
 		} else {
 			strbuf_reset(&buf);
 			strbuf_addstr(&buf, options.state_dir);
-			ret = !!remove_dir_recursively(&buf, 0);
+			ret = remove_dir_recursively(&buf, 0);
 			if (ret)
 				error(_("could not remove '%s'"),
 				       options.state_dir);
@@ -1702,7 +1407,7 @@
 		if (options.ignore_date)
 			strvec_push(&options.git_am_opts, "--ignore-date");
 	} else {
-		/* REBASE_MERGE and PRESERVE_MERGES */
+		/* REBASE_MERGE */
 		if (ignore_whitespace) {
 			string_list_append(&strategy_options,
 					   "ignore-space-change");
@@ -1713,7 +1418,7 @@
 		int i;
 
 		if (!options.strategy)
-			options.strategy = "recursive";
+			options.strategy = "ort";
 
 		strbuf_reset(&buf);
 		for (i = 0; i < strategy_options.nr; i++)
@@ -1728,7 +1433,6 @@
 		case REBASE_APPLY:
 			die(_("--strategy requires --merge or --interactive"));
 		case REBASE_MERGE:
-		case REBASE_PRESERVE_MERGES:
 			/* compatible */
 			break;
 		case REBASE_UNSPECIFIED:
@@ -1780,7 +1484,6 @@
 
 	switch (options.type) {
 	case REBASE_MERGE:
-	case REBASE_PRESERVE_MERGES:
 		options.state_dir = merge_dir();
 		break;
 	case REBASE_APPLY:
@@ -1805,28 +1508,10 @@
 		options.reschedule_failed_exec = reschedule_failed_exec;
 
 	if (options.signoff) {
-		if (options.type == REBASE_PRESERVE_MERGES)
-			die("cannot combine '--signoff' with "
-			    "'--preserve-merges'");
 		strvec_push(&options.git_am_opts, "--signoff");
 		options.flags |= REBASE_FORCE;
 	}
 
-	if (options.type == REBASE_PRESERVE_MERGES) {
-		/*
-		 * Note: incompatibility with --signoff handled in signoff block above
-		 * Note: incompatibility with --interactive is just a strong warning;
-		 *       git-rebase.txt caveats with "unless you know what you are doing"
-		 */
-		if (options.rebase_merges)
-			die(_("cannot combine '--preserve-merges' with "
-			      "'--rebase-merges'"));
-
-		if (options.reschedule_failed_exec)
-			die(_("error: cannot combine '--preserve-merges' with "
-			      "'--reschedule-failed-exec'"));
-	}
-
 	if (!options.root) {
 		if (argc < 1) {
 			struct branch *branch;
@@ -1845,7 +1530,8 @@
 			if (!strcmp(options.upstream_name, "-"))
 				options.upstream_name = "@{-1}";
 		}
-		options.upstream = peel_committish(options.upstream_name);
+		options.upstream =
+			lookup_commit_reference_by_name(options.upstream_name);
 		if (!options.upstream)
 			die(_("invalid upstream '%s'"), options.upstream_name);
 		options.upstream_arg = options.upstream_name;
@@ -1888,7 +1574,8 @@
 		options.onto = lookup_commit_or_die(&merge_base,
 						    options.onto_name);
 	} else {
-		options.onto = peel_committish(options.onto_name);
+		options.onto =
+			lookup_commit_reference_by_name(options.onto_name);
 		if (!options.onto)
 			die(_("Does not point to a valid commit '%s'"),
 				options.onto_name);
@@ -1913,13 +1600,15 @@
 			die_if_checked_out(buf.buf, 1);
 			options.head_name = xstrdup(buf.buf);
 		/* If not is it a valid ref (branch or commit)? */
-		} else if (!get_oid(branch_name, &options.orig_head) &&
-			   lookup_commit_reference(the_repository,
-						   &options.orig_head))
+		} else {
+			struct commit *commit =
+				lookup_commit_reference_by_name(branch_name);
+			if (!commit)
+				die(_("no such branch/commit '%s'"),
+				    branch_name);
+			oidcpy(&options.orig_head, &commit->object.oid);
 			options.head_name = NULL;
-		else
-			die(_("no such branch/commit '%s'"),
-			    branch_name);
+		}
 	} else if (argc == 0) {
 		/* Do not need to switch branches, we are already on it. */
 		options.head_name =
@@ -1959,7 +1648,7 @@
 
 	if (require_clean_work_tree(the_repository, "rebase",
 				    _("Please commit or stash them."), 1, 1)) {
-		ret = 1;
+		ret = -1;
 		goto cleanup;
 	}
 
@@ -1994,7 +1683,7 @@
 					       RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
 					       NULL, buf.buf,
 					       DEFAULT_REFLOG_ACTION) < 0) {
-					ret = !!error(_("could not switch to "
+					ret = error(_("could not switch to "
 							"%s"),
 						      options.switch_to);
 					goto cleanup;
@@ -2009,7 +1698,7 @@
 			else
 				printf(_("Current branch %s is up to date.\n"),
 				       branch_name);
-			ret = !!finish_rebase(&options);
+			ret = finish_rebase(&options);
 			goto cleanup;
 		} else if (!(options.flags & REBASE_NO_QUIET))
 			; /* be quiet */
@@ -2087,7 +1776,7 @@
 			   RESET_HEAD_REFS_ONLY, "HEAD", msg.buf,
 			   DEFAULT_REFLOG_ACTION);
 		strbuf_release(&msg);
-		ret = !!finish_rebase(&options);
+		ret = finish_rebase(&options);
 		goto cleanup;
 	}
 
@@ -2101,7 +1790,7 @@
 	options.revisions = revisions.buf;
 
 run_rebase:
-	ret = !!run_specific_rebase(&options, action);
+	ret = run_specific_rebase(&options, action);
 
 cleanup:
 	strbuf_release(&buf);
@@ -2112,5 +1801,5 @@
 	free(options.strategy);
 	strbuf_release(&options.git_format_patch_opt);
 	free(squash_onto_name);
-	return ret;
+	return !!ret;
 }
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 2d1f97e..49b846d 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -7,6 +7,7 @@
 #include "pkt-line.h"
 #include "sideband.h"
 #include "run-command.h"
+#include "hook.h"
 #include "exec-cmd.h"
 #include "commit.h"
 #include "object.h"
@@ -134,6 +135,10 @@
 	if (status)
 		return status;
 
+	status = git_gpg_config(var, value, NULL);
+	if (status)
+		return status;
+
 	if (strcmp(var, "receive.denydeletes") == 0) {
 		deny_deletes = git_config_bool(var, value);
 		return 0;
@@ -1306,7 +1311,7 @@
 	rp_error("%s", _(refuse_unconfigured_deny_delete_current_msg));
 }
 
-static int command_singleton_iterator(void *cb_data, struct object_id *oid);
+static const struct object_id *command_singleton_iterator(void *cb_data);
 static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
 {
 	struct shallow_lock shallow_lock = SHALLOW_LOCK_INIT;
@@ -1463,7 +1468,7 @@
 
 	strvec_pushf(&env, "GIT_DIR=%s", absolute_path(git_dir));
 
-	if (!find_hook(push_to_checkout_hook))
+	if (!hook_exists(push_to_checkout_hook))
 		retval = push_to_deploy(sha1, &env, work_tree);
 	else
 		retval = push_to_checkout(sha1, &env, work_tree);
@@ -1731,16 +1736,15 @@
 	string_list_clear(&ref_list, 0);
 }
 
-static int command_singleton_iterator(void *cb_data, struct object_id *oid)
+static const struct object_id *command_singleton_iterator(void *cb_data)
 {
 	struct command **cmd_list = cb_data;
 	struct command *cmd = *cmd_list;
 
 	if (!cmd || is_null_oid(&cmd->new_oid))
-		return -1; /* end of list */
+		return NULL;
 	*cmd_list = NULL; /* this returns only one */
-	oidcpy(oid, &cmd->new_oid);
-	return 0;
+	return &cmd->new_oid;
 }
 
 static void set_connectivity_errors(struct command *commands,
@@ -1770,7 +1774,7 @@
 	struct shallow_info *si;
 };
 
-static int iterate_receive_command_list(void *cb_data, struct object_id *oid)
+static const struct object_id *iterate_receive_command_list(void *cb_data)
 {
 	struct iterate_data *data = cb_data;
 	struct command **cmd_list = &data->cmds;
@@ -1781,13 +1785,11 @@
 			/* to be checked in update_shallow_ref() */
 			continue;
 		if (!is_null_oid(&cmd->new_oid) && !cmd->skip_update) {
-			oidcpy(oid, &cmd->new_oid);
 			*cmd_list = cmd->next;
-			return 0;
+			return &cmd->new_oid;
 		}
 	}
-	*cmd_list = NULL;
-	return -1; /* end of list */
+	return NULL;
 }
 
 static void reject_updates_to_hidden(struct command *commands)
@@ -2477,7 +2479,8 @@
 	struct option options[] = {
 		OPT__QUIET(&quiet, N_("quiet")),
 		OPT_HIDDEN_BOOL(0, "stateless-rpc", &stateless_rpc, NULL),
-		OPT_HIDDEN_BOOL(0, "advertise-refs", &advertise_refs, NULL),
+		OPT_HIDDEN_BOOL(0, "http-backend-info-refs", &advertise_refs, NULL),
+		OPT_ALIAS(0, "advertise-refs", "http-backend-info-refs"),
 		OPT_HIDDEN_BOOL(0, "reject-thin-pack-for-testing", &reject_thin, NULL),
 		OPT_END()
 	};
@@ -2580,10 +2583,9 @@
 			proc.no_stdin = 1;
 			proc.stdout_to_stderr = 1;
 			proc.err = use_sideband ? -1 : 0;
-			proc.git_cmd = 1;
+			proc.git_cmd = proc.close_object_store = 1;
 			proc.argv = argv_gc_auto;
 
-			close_object_store(the_repository->objects);
 			if (!start_command(&proc)) {
 				if (use_sideband)
 					copy_to_sideband(proc.err, -1, NULL);
diff --git a/builtin/reflog.c b/builtin/reflog.c
index 09541d1..175c83e 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -629,8 +629,9 @@
 		free_worktrees(worktrees);
 		for (i = 0; i < collected.nr; i++) {
 			struct collected_reflog *e = collected.e[i];
+
 			set_reflog_expiry_param(&cb.cmd, explicit_expiry, e->reflog);
-			status |= reflog_expire(e->reflog, &e->oid, flags,
+			status |= reflog_expire(e->reflog, flags,
 						reflog_expiry_prepare,
 						should_expire_reflog_ent,
 						reflog_expiry_cleanup,
@@ -642,17 +643,17 @@
 
 	for (; i < argc; i++) {
 		char *ref;
-		struct object_id oid;
-		if (!dwim_log(argv[i], strlen(argv[i]), &oid, &ref)) {
+		if (!dwim_log(argv[i], strlen(argv[i]), NULL, &ref)) {
 			status |= error(_("%s points nowhere!"), argv[i]);
 			continue;
 		}
 		set_reflog_expiry_param(&cb.cmd, explicit_expiry, ref);
-		status |= reflog_expire(ref, &oid, flags,
+		status |= reflog_expire(ref, flags,
 					reflog_expiry_prepare,
 					should_expire_reflog_ent,
 					reflog_expiry_cleanup,
 					&cb);
+		free(ref);
 	}
 	return status;
 }
@@ -700,7 +701,6 @@
 
 	for ( ; i < argc; i++) {
 		const char *spec = strstr(argv[i], "@{");
-		struct object_id oid;
 		char *ep, *ref;
 		int recno;
 
@@ -709,7 +709,7 @@
 			continue;
 		}
 
-		if (!dwim_log(argv[i], spec - argv[i], &oid, &ref)) {
+		if (!dwim_log(argv[i], spec - argv[i], NULL, &ref)) {
 			status |= error(_("no reflog for '%s'"), argv[i]);
 			continue;
 		}
@@ -724,7 +724,7 @@
 			cb.cmd.expire_total = 0;
 		}
 
-		status |= reflog_expire(ref, &oid, flags,
+		status |= reflog_expire(ref, flags,
 					reflog_expiry_prepare,
 					should_expire_reflog_ent,
 					reflog_expiry_cleanup,
diff --git a/builtin/remote.c b/builtin/remote.c
index 7f88e6c..299c466 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -318,6 +318,9 @@
 		 * truth value with >= REBASE_TRUE.
 		 */
 		info->rebase = rebase_parse_value(value);
+		if (info->rebase == REBASE_INVALID)
+			warning(_("unhandled branch.%s.rebase=%s; assuming "
+				  "'true'"), name, value);
 		break;
 	case PUSH_REMOTE:
 		if (info->push_remote_name)
@@ -344,6 +347,14 @@
 	int queried;
 };
 
+#define REF_STATES_INIT { \
+	.new_refs = STRING_LIST_INIT_DUP, \
+	.stale = STRING_LIST_INIT_DUP, \
+	.tracked = STRING_LIST_INIT_DUP, \
+	.heads = STRING_LIST_INIT_DUP, \
+	.push = STRING_LIST_INIT_DUP, \
+}
+
 static int get_ref_states(const struct ref *remote_refs, struct ref_states *states)
 {
 	struct ref *fetch_map = NULL, **tail = &fetch_map;
@@ -355,9 +366,6 @@
 			die(_("Could not get fetch map for refspec %s"),
 				states->remote->fetch.raw[i]);
 
-	states->new_refs.strdup_strings = 1;
-	states->tracked.strdup_strings = 1;
-	states->stale.strdup_strings = 1;
 	for (ref = fetch_map; ref; ref = ref->next) {
 		if (!ref->peer_ref || !ref_exists(ref->peer_ref->name))
 			string_list_append(&states->new_refs, abbrev_branch(ref->name));
@@ -406,7 +414,6 @@
 
 	match_push_refs(local_refs, &push_map, &remote->push, MATCH_REFS_NONE);
 
-	states->push.strdup_strings = 1;
 	for (ref = push_map; ref; ref = ref->next) {
 		struct string_list_item *item;
 		struct push_info *info;
@@ -449,7 +456,6 @@
 	if (remote->mirror)
 		return 0;
 
-	states->push.strdup_strings = 1;
 	if (!remote->push.nr) {
 		item = string_list_append(&states->push, _("(matching)"));
 		info = item->util = xcalloc(1, sizeof(struct push_info));
@@ -483,7 +489,6 @@
 	refspec.force = 0;
 	refspec.pattern = 1;
 	refspec.src = refspec.dst = "refs/heads/*";
-	states->heads.strdup_strings = 1;
 	get_fetch_map(remote_refs, &refspec, &fetch_map_tail, 0);
 	matches = guess_remote_head(find_ref_by_name(remote_refs, "HEAD"),
 				    fetch_map, 1);
@@ -970,26 +975,31 @@
 }
 
 struct show_info {
-	struct string_list *list;
-	struct ref_states *states;
+	struct string_list list;
+	struct ref_states states;
 	int width, width2;
 	int any_rebase;
 };
 
+#define SHOW_INFO_INIT { \
+	.list = STRING_LIST_INIT_DUP, \
+	.states = REF_STATES_INIT, \
+}
+
 static int add_remote_to_show_info(struct string_list_item *item, void *cb_data)
 {
 	struct show_info *info = cb_data;
 	int n = strlen(item->string);
 	if (n > info->width)
 		info->width = n;
-	string_list_insert(info->list, item->string);
+	string_list_insert(&info->list, item->string);
 	return 0;
 }
 
 static int show_remote_info_item(struct string_list_item *item, void *cb_data)
 {
 	struct show_info *info = cb_data;
-	struct ref_states *states = info->states;
+	struct ref_states *states = &info->states;
 	const char *name = item->string;
 
 	if (states->queried) {
@@ -1016,7 +1026,7 @@
 static int add_local_to_show_info(struct string_list_item *branch_item, void *cb_data)
 {
 	struct show_info *show_info = cb_data;
-	struct ref_states *states = show_info->states;
+	struct ref_states *states = &show_info->states;
 	struct branch_info *branch_info = branch_item->util;
 	struct string_list_item *item;
 	int n;
@@ -1029,7 +1039,7 @@
 	if (branch_info->rebase >= REBASE_TRUE)
 		show_info->any_rebase = 1;
 
-	item = string_list_insert(show_info->list, branch_item->string);
+	item = string_list_insert(&show_info->list, branch_item->string);
 	item->util = branch_info;
 
 	return 0;
@@ -1084,7 +1094,7 @@
 		show_info->width = n;
 	if ((n = strlen(push_info->dest)) > show_info->width2)
 		show_info->width2 = n;
-	item = string_list_append(show_info->list, push_item->string);
+	item = string_list_append(&show_info->list, push_item->string);
 	item->util = push_item->util;
 	return 0;
 }
@@ -1212,9 +1222,7 @@
 		OPT_BOOL('n', NULL, &no_query, N_("do not query remotes")),
 		OPT_END()
 	};
-	struct ref_states states;
-	struct string_list info_list = STRING_LIST_INIT_NODUP;
-	struct show_info info;
+	struct show_info info = SHOW_INFO_INIT;
 
 	argc = parse_options(argc, argv, NULL, options, builtin_remote_show_usage,
 			     0);
@@ -1225,26 +1233,22 @@
 	if (!no_query)
 		query_flag = (GET_REF_STATES | GET_HEAD_NAMES | GET_PUSH_REF_STATES);
 
-	memset(&states, 0, sizeof(states));
-	memset(&info, 0, sizeof(info));
-	info.states = &states;
-	info.list = &info_list;
 	for (; argc; argc--, argv++) {
 		int i;
 		const char **url;
 		int url_nr;
 
-		get_remote_ref_states(*argv, &states, query_flag);
+		get_remote_ref_states(*argv, &info.states, query_flag);
 
 		printf_ln(_("* remote %s"), *argv);
-		printf_ln(_("  Fetch URL: %s"), states.remote->url_nr > 0 ?
-		       states.remote->url[0] : _("(no URL)"));
-		if (states.remote->pushurl_nr) {
-			url = states.remote->pushurl;
-			url_nr = states.remote->pushurl_nr;
+		printf_ln(_("  Fetch URL: %s"), info.states.remote->url_nr > 0 ?
+		       info.states.remote->url[0] : _("(no URL)"));
+		if (info.states.remote->pushurl_nr) {
+			url = info.states.remote->pushurl;
+			url_nr = info.states.remote->pushurl_nr;
 		} else {
-			url = states.remote->url;
-			url_nr = states.remote->url_nr;
+			url = info.states.remote->url;
+			url_nr = info.states.remote->url_nr;
 		}
 		for (i = 0; i < url_nr; i++)
 			/*
@@ -1257,57 +1261,57 @@
 			printf_ln(_("  Push  URL: %s"), _("(no URL)"));
 		if (no_query)
 			printf_ln(_("  HEAD branch: %s"), _("(not queried)"));
-		else if (!states.heads.nr)
+		else if (!info.states.heads.nr)
 			printf_ln(_("  HEAD branch: %s"), _("(unknown)"));
-		else if (states.heads.nr == 1)
-			printf_ln(_("  HEAD branch: %s"), states.heads.items[0].string);
+		else if (info.states.heads.nr == 1)
+			printf_ln(_("  HEAD branch: %s"), info.states.heads.items[0].string);
 		else {
 			printf(_("  HEAD branch (remote HEAD is ambiguous,"
 				 " may be one of the following):\n"));
-			for (i = 0; i < states.heads.nr; i++)
-				printf("    %s\n", states.heads.items[i].string);
+			for (i = 0; i < info.states.heads.nr; i++)
+				printf("    %s\n", info.states.heads.items[i].string);
 		}
 
 		/* remote branch info */
 		info.width = 0;
-		for_each_string_list(&states.new_refs, add_remote_to_show_info, &info);
-		for_each_string_list(&states.tracked, add_remote_to_show_info, &info);
-		for_each_string_list(&states.stale, add_remote_to_show_info, &info);
-		if (info.list->nr)
+		for_each_string_list(&info.states.new_refs, 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)
 			printf_ln(Q_("  Remote branch:%s",
 				     "  Remote branches:%s",
-				     info.list->nr),
+				     info.list.nr),
 				  no_query ? _(" (status not queried)") : "");
-		for_each_string_list(info.list, show_remote_info_item, &info);
-		string_list_clear(info.list, 0);
+		for_each_string_list(&info.list, show_remote_info_item, &info);
+		string_list_clear(&info.list, 0);
 
 		/* git pull info */
 		info.width = 0;
 		info.any_rebase = 0;
 		for_each_string_list(&branch_list, add_local_to_show_info, &info);
-		if (info.list->nr)
+		if (info.list.nr)
 			printf_ln(Q_("  Local branch configured for 'git pull':",
 				     "  Local branches configured for 'git pull':",
-				     info.list->nr));
-		for_each_string_list(info.list, show_local_info_item, &info);
-		string_list_clear(info.list, 0);
+				     info.list.nr));
+		for_each_string_list(&info.list, show_local_info_item, &info);
+		string_list_clear(&info.list, 0);
 
 		/* git push info */
-		if (states.remote->mirror)
+		if (info.states.remote->mirror)
 			printf_ln(_("  Local refs will be mirrored by 'git push'"));
 
 		info.width = info.width2 = 0;
-		for_each_string_list(&states.push, add_push_to_show_info, &info);
-		QSORT(info.list->items, info.list->nr, cmp_string_with_push);
-		if (info.list->nr)
+		for_each_string_list(&info.states.push, add_push_to_show_info, &info);
+		QSORT(info.list.items, info.list.nr, cmp_string_with_push);
+		if (info.list.nr)
 			printf_ln(Q_("  Local ref configured for 'git push'%s:",
 				     "  Local refs configured for 'git push'%s:",
-				     info.list->nr),
+				     info.list.nr),
 				  no_query ? _(" (status not queried)") : "");
-		for_each_string_list(info.list, show_push_info_item, &info);
-		string_list_clear(info.list, 0);
+		for_each_string_list(&info.list, show_push_info_item, &info);
+		string_list_clear(&info.list, 0);
 
-		free_remote_ref_states(&states);
+		free_remote_ref_states(&info.states);
 	}
 
 	return result;
@@ -1334,8 +1338,7 @@
 	if (!opt_a && !opt_d && argc == 2) {
 		head_name = xstrdup(argv[1]);
 	} else if (opt_a && !opt_d && argc == 1) {
-		struct ref_states states;
-		memset(&states, 0, sizeof(states));
+		struct ref_states states = REF_STATES_INIT;
 		get_remote_ref_states(argv[0], &states, GET_HEAD_NAMES);
 		if (!states.heads.nr)
 			result |= error(_("Cannot determine remote HEAD"));
@@ -1374,14 +1377,13 @@
 static int prune_remote(const char *remote, int dry_run)
 {
 	int result = 0;
-	struct ref_states states;
+	struct ref_states states = REF_STATES_INIT;
 	struct string_list refs_to_prune = STRING_LIST_INIT_NODUP;
 	struct string_list_item *item;
 	const char *dangling_msg = dry_run
 		? _(" %s will become dangling!")
 		: _(" %s has become dangling!");
 
-	memset(&states, 0, sizeof(states));
 	get_remote_ref_states(remote, &states, GET_REF_STATES);
 
 	if (!states.stale.nr) {
diff --git a/builtin/repack.c b/builtin/repack.c
index c3e4771..0b2d1e5 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -15,6 +15,8 @@
 #include "promisor-remote.h"
 #include "shallow.h"
 #include "pack.h"
+#include "pack-bitmap.h"
+#include "refs.h"
 
 static int delta_base_offset = 1;
 static int pack_kept_objects = -1;
@@ -94,12 +96,14 @@
 }
 
 /*
- * Adds all packs hex strings to the fname list, which do not
- * have a corresponding .keep file. These packs are not to
- * be kept if we are going to pack everything into one file.
+ * Adds all packs hex strings to either fname_nonkept_list or
+ * fname_kept_list based on whether each pack has a corresponding
+ * .keep file or not.  Packs without a .keep file are not to be kept
+ * if we are going to pack everything into one file.
  */
-static void get_non_kept_pack_filenames(struct string_list *fname_list,
-					const struct string_list *extra_keep)
+static void collect_pack_filenames(struct string_list *fname_nonkept_list,
+				   struct string_list *fname_kept_list,
+				   const struct string_list *extra_keep)
 {
 	DIR *dir;
 	struct dirent *e;
@@ -112,21 +116,20 @@
 		size_t len;
 		int i;
 
-		for (i = 0; i < extra_keep->nr; i++)
-			if (!fspathcmp(e->d_name, extra_keep->items[i].string))
-				break;
-		if (extra_keep->nr > 0 && i < extra_keep->nr)
-			continue;
-
 		if (!strip_suffix(e->d_name, ".pack", &len))
 			continue;
 
+		for (i = 0; i < extra_keep->nr; i++)
+			if (!fspathcmp(e->d_name, extra_keep->items[i].string))
+				break;
+
 		fname = xmemdupz(e->d_name, len);
 
-		if (!file_exists(mkpath("%s/%s.keep", packdir, fname)))
-			string_list_append_nodup(fname_list, fname);
+		if ((extra_keep->nr > 0 && i < extra_keep->nr) ||
+		    (file_exists(mkpath("%s/%s.keep", packdir, fname))))
+			string_list_append_nodup(fname_kept_list, fname);
 		else
-			free(fname);
+			string_list_append_nodup(fname_nonkept_list, fname);
 	}
 	closedir(dir);
 }
@@ -422,6 +425,25 @@
 	geometry->split = split;
 }
 
+static struct packed_git *get_largest_active_pack(struct pack_geometry *geometry)
+{
+	if (!geometry) {
+		/*
+		 * No geometry means either an all-into-one repack (in which
+		 * case there is only one pack left and it is the largest) or an
+		 * incremental one.
+		 *
+		 * If repacking incrementally, then we could check the size of
+		 * all packs to determine which should be preferred, but leave
+		 * this for later.
+		 */
+		return NULL;
+	}
+	if (geometry->split == geometry->pack_nr)
+		return NULL;
+	return geometry->pack[geometry->pack_nr - 1];
+}
+
 static void clear_pack_geometry(struct pack_geometry *geometry)
 {
 	if (!geometry)
@@ -433,17 +455,162 @@
 	geometry->split = 0;
 }
 
+struct midx_snapshot_ref_data {
+	struct tempfile *f;
+	struct oidset seen;
+	int preferred;
+};
+
+static int midx_snapshot_ref_one(const char *refname,
+				 const struct object_id *oid,
+				 int flag, void *_data)
+{
+	struct midx_snapshot_ref_data *data = _data;
+	struct object_id peeled;
+
+	if (!peel_iterated_oid(oid, &peeled))
+		oid = &peeled;
+
+	if (oidset_insert(&data->seen, oid))
+		return 0; /* already seen */
+
+	if (oid_object_info(the_repository, oid, NULL) != OBJ_COMMIT)
+		return 0;
+
+	fprintf(data->f->fp, "%s%s\n", data->preferred ? "+" : "",
+		oid_to_hex(oid));
+
+	return 0;
+}
+
+static void midx_snapshot_refs(struct tempfile *f)
+{
+	struct midx_snapshot_ref_data data;
+	const struct string_list *preferred = bitmap_preferred_tips(the_repository);
+
+	data.f = f;
+	data.preferred = 0;
+	oidset_init(&data.seen, 0);
+
+	if (!fdopen_tempfile(f, "w"))
+		 die(_("could not open tempfile %s for writing"),
+		     get_tempfile_path(f));
+
+	if (preferred) {
+		struct string_list_item *item;
+
+		data.preferred = 1;
+		for_each_string_list_item(item, preferred)
+			for_each_ref_in(item->string, midx_snapshot_ref_one, &data);
+		data.preferred = 0;
+	}
+
+	for_each_ref(midx_snapshot_ref_one, &data);
+
+	if (close_tempfile_gently(f)) {
+		int save_errno = errno;
+		delete_tempfile(&f);
+		errno = save_errno;
+		die_errno(_("could not close refs snapshot tempfile"));
+	}
+
+	oidset_clear(&data.seen);
+}
+
+static void midx_included_packs(struct string_list *include,
+				struct string_list *existing_nonkept_packs,
+				struct string_list *existing_kept_packs,
+				struct string_list *names,
+				struct pack_geometry *geometry)
+{
+	struct string_list_item *item;
+
+	for_each_string_list_item(item, existing_kept_packs)
+		string_list_insert(include, xstrfmt("%s.idx", item->string));
+	for_each_string_list_item(item, names)
+		string_list_insert(include, xstrfmt("pack-%s.idx", item->string));
+	if (geometry) {
+		struct strbuf buf = STRBUF_INIT;
+		uint32_t i;
+		for (i = geometry->split; i < geometry->pack_nr; i++) {
+			struct packed_git *p = geometry->pack[i];
+
+			strbuf_addstr(&buf, pack_basename(p));
+			strbuf_strip_suffix(&buf, ".pack");
+			strbuf_addstr(&buf, ".idx");
+
+			string_list_insert(include, strbuf_detach(&buf, NULL));
+		}
+	} else {
+		for_each_string_list_item(item, existing_nonkept_packs) {
+			if (item->util)
+				continue;
+			string_list_insert(include, xstrfmt("%s.idx", item->string));
+		}
+	}
+}
+
+static int write_midx_included_packs(struct string_list *include,
+				     struct pack_geometry *geometry,
+				     const char *refs_snapshot,
+				     int show_progress, int write_bitmaps)
+{
+	struct child_process cmd = CHILD_PROCESS_INIT;
+	struct string_list_item *item;
+	struct packed_git *largest = get_largest_active_pack(geometry);
+	FILE *in;
+	int ret;
+
+	if (!include->nr)
+		return 0;
+
+	cmd.in = -1;
+	cmd.git_cmd = 1;
+
+	strvec_push(&cmd.args, "multi-pack-index");
+	strvec_pushl(&cmd.args, "write", "--stdin-packs", NULL);
+
+	if (show_progress)
+		strvec_push(&cmd.args, "--progress");
+	else
+		strvec_push(&cmd.args, "--no-progress");
+
+	if (write_bitmaps)
+		strvec_push(&cmd.args, "--bitmap");
+
+	if (largest)
+		strvec_pushf(&cmd.args, "--preferred-pack=%s",
+			     pack_basename(largest));
+
+	if (refs_snapshot)
+		strvec_pushf(&cmd.args, "--refs-snapshot=%s", refs_snapshot);
+
+	ret = start_command(&cmd);
+	if (ret)
+		return ret;
+
+	in = xfdopen(cmd.in, "w");
+	for_each_string_list_item(item, include)
+		fprintf(in, "%s\n", item->string);
+	fclose(in);
+
+	return finish_command(&cmd);
+}
+
 int cmd_repack(int argc, const char **argv, const char *prefix)
 {
 	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_packs = STRING_LIST_INIT_DUP;
+	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;
 	struct strbuf line = STRBUF_INIT;
+	struct tempfile *refs_snapshot = NULL;
 	int i, ext, ret;
 	FILE *out;
+	int show_progress = isatty(2);
 
 	/* variables to be filled by option parsing */
 	int pack_everything = 0;
@@ -454,6 +621,7 @@
 	int no_update_server_info = 0;
 	struct pack_objects_args po_args = {NULL};
 	int geometric_factor = 0;
+	int write_midx = 0;
 
 	struct option builtin_repack_options[] = {
 		OPT_BIT('a', NULL, &pack_everything,
@@ -496,6 +664,8 @@
 				N_("do not repack this pack")),
 		OPT_INTEGER('g', "geometric", &geometric_factor,
 			    N_("find a geometric progression with factor <N>")),
+		OPT_BOOL('m', "write-midx", &write_midx,
+			   N_("write a multi-pack index of the resulting packs")),
 		OPT_END()
 	};
 
@@ -512,16 +682,32 @@
 		die(_("--keep-unreachable and -A are incompatible"));
 
 	if (write_bitmaps < 0) {
-		if (!(pack_everything & ALL_INTO_ONE) ||
-		    !is_bare_repository())
+		if (!write_midx &&
+		    (!(pack_everything & ALL_INTO_ONE) || !is_bare_repository()))
 			write_bitmaps = 0;
+	} else if (write_bitmaps &&
+		   git_env_bool(GIT_TEST_MULTI_PACK_INDEX, 0) &&
+		   git_env_bool(GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP, 0)) {
+		write_bitmaps = 0;
 	}
 	if (pack_kept_objects < 0)
 		pack_kept_objects = write_bitmaps > 0;
 
-	if (write_bitmaps && !(pack_everything & ALL_INTO_ONE))
+	if (write_bitmaps && !(pack_everything & ALL_INTO_ONE) && !write_midx)
 		die(_(incremental_bitmap_conflict_error));
 
+	if (write_midx && write_bitmaps) {
+		struct strbuf path = STRBUF_INIT;
+
+		strbuf_addf(&path, "%s/%s_XXXXXX", get_object_directory(),
+			    "bitmap-ref-tips");
+
+		refs_snapshot = xmks_tempfile(path.buf);
+		midx_snapshot_refs(refs_snapshot);
+
+		strbuf_release(&path);
+	}
+
 	if (geometric_factor) {
 		if (pack_everything)
 			die(_("--geometric is incompatible with -A, -a"));
@@ -561,19 +747,22 @@
 	}
 	if (has_promisor_remote())
 		strvec_push(&cmd.args, "--exclude-promisor-objects");
-	if (write_bitmaps > 0)
-		strvec_push(&cmd.args, "--write-bitmap-index");
-	else if (write_bitmaps < 0)
-		strvec_push(&cmd.args, "--write-bitmap-index-quiet");
+	if (!write_midx) {
+		if (write_bitmaps > 0)
+			strvec_push(&cmd.args, "--write-bitmap-index");
+		else if (write_bitmaps < 0)
+			strvec_push(&cmd.args, "--write-bitmap-index-quiet");
+	}
 	if (use_delta_islands)
 		strvec_push(&cmd.args, "--delta-islands");
 
-	if (pack_everything & ALL_INTO_ONE) {
-		get_non_kept_pack_filenames(&existing_packs, &keep_pack_list);
+	collect_pack_filenames(&existing_nonkept_packs, &existing_kept_packs,
+			       &keep_pack_list);
 
+	if (pack_everything & ALL_INTO_ONE) {
 		repack_promisor_objects(&po_args, &names);
 
-		if (existing_packs.nr && delete_redundant) {
+		if (existing_nonkept_packs.nr && delete_redundant) {
 			for_each_string_list_item(item, &names) {
 				strvec_pushf(&cmd.args, "--keep-pack=%s-%s.pack",
 					     packtmp_name, item->string);
@@ -582,15 +771,12 @@
 				strvec_pushf(&cmd.args,
 					     "--unpack-unreachable=%s",
 					     unpack_unreachable);
-				strvec_push(&cmd.env_array, "GIT_REF_PARANOIA=1");
 			} else if (pack_everything & LOOSEN_UNREACHABLE) {
 				strvec_push(&cmd.args,
 					    "--unpack-unreachable");
 			} else if (keep_unreachable) {
 				strvec_push(&cmd.args, "--keep-unreachable");
 				strvec_push(&cmd.args, "--pack-loose-unreachable");
-			} else {
-				strvec_push(&cmd.env_array, "GIT_REF_PARANOIA=1");
 			}
 		}
 	} else if (geometry) {
@@ -676,20 +862,48 @@
 	}
 	/* End of pack replacement. */
 
-	reprepare_packed_git(the_repository);
-
-	if (delete_redundant) {
+	if (delete_redundant && pack_everything & ALL_INTO_ONE) {
 		const int hexsz = the_hash_algo->hexsz;
-		int opts = 0;
 		string_list_sort(&names);
-		for_each_string_list_item(item, &existing_packs) {
+		for_each_string_list_item(item, &existing_nonkept_packs) {
 			char *sha1;
 			size_t len = strlen(item->string);
 			if (len < hexsz)
 				continue;
 			sha1 = item->string + len - hexsz;
-			if (!string_list_has_string(&names, sha1))
-				remove_redundant_pack(packdir, item->string);
+			/*
+			 * Mark this pack for deletion, which ensures that this
+			 * pack won't be included in a MIDX (if `--write-midx`
+			 * was given) and that we will actually delete this pack
+			 * (if `-d` was given).
+			 */
+			item->util = (void*)(intptr_t)!string_list_has_string(&names, sha1);
+		}
+	}
+
+	if (write_midx) {
+		struct string_list include = STRING_LIST_INIT_NODUP;
+		midx_included_packs(&include, &existing_nonkept_packs,
+				    &existing_kept_packs, &names, geometry);
+
+		ret = write_midx_included_packs(&include, geometry,
+						refs_snapshot ? get_tempfile_path(refs_snapshot) : NULL,
+						show_progress, write_bitmaps > 0);
+
+		string_list_clear(&include, 0);
+
+		if (ret)
+			return ret;
+	}
+
+	reprepare_packed_git(the_repository);
+
+	if (delete_redundant) {
+		int opts = 0;
+		for_each_string_list_item(item, &existing_nonkept_packs) {
+			if (!item->util)
+				continue;
+			remove_redundant_pack(packdir, item->string);
 		}
 
 		if (geometry) {
@@ -710,7 +924,7 @@
 			}
 			strbuf_release(&buf);
 		}
-		if (!po_args.quiet && isatty(2))
+		if (!po_args.quiet && show_progress)
 			opts |= PRUNE_PACKED_VERBOSE;
 		prune_packed_objects(opts);
 
@@ -725,12 +939,17 @@
 		update_server_info(0);
 	remove_temporary_files();
 
-	if (git_env_bool(GIT_TEST_MULTI_PACK_INDEX, 0))
-		write_midx_file(get_object_directory(), NULL, 0);
+	if (git_env_bool(GIT_TEST_MULTI_PACK_INDEX, 0)) {
+		unsigned flags = 0;
+		if (git_env_bool(GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP, 0))
+			flags |= MIDX_WRITE_BITMAP | MIDX_WRITE_REV_INDEX;
+		write_midx_file(get_object_directory(), NULL, NULL, flags);
+	}
 
 	string_list_clear(&names, 0);
 	string_list_clear(&rollback, 0);
-	string_list_clear(&existing_packs, 0);
+	string_list_clear(&existing_nonkept_packs, 0);
+	string_list_clear(&existing_kept_packs, 0);
 	clear_pack_geometry(geometry);
 	strbuf_release(&line);
 
diff --git a/builtin/replace.c b/builtin/replace.c
index cd48765..946938d 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -507,7 +507,7 @@
 	if (!fp)
 		return -1;
 
-	advice_graft_file_deprecated = 0;
+	no_graft_file_deprecated_advice = 1;
 	while (strbuf_getline(&buf, fp) != EOF) {
 		if (*buf.buf == '#')
 			continue;
diff --git a/builtin/reset.c b/builtin/reset.c
index 43e855c..7393595 100644
--- a/builtin/reset.c
+++ b/builtin/reset.c
@@ -67,12 +67,18 @@
 	case KEEP:
 	case MERGE:
 		opts.update = 1;
+		opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
 		break;
 	case HARD:
 		opts.update = 1;
-		/* fallthrough */
+		opts.reset = UNPACK_RESET_OVERWRITE_UNTRACKED;
+		break;
+	case MIXED:
+		opts.reset = UNPACK_RESET_PROTECT_UNTRACKED;
+		/* but opts.update=0, so working tree not updated */
+		break;
 	default:
-		opts.reset = 1;
+		BUG("invalid reset_type passed to reset_index");
 	}
 
 	read_cache_unmerged();
@@ -412,7 +418,7 @@
 				refresh_index(&the_index, flags, NULL, NULL,
 					      _("Unstaged changes after reset:"));
 				t_delta_in_ms = (getnanotime() - t_begin) / 1000000;
-				if (advice_reset_quiet_warning && t_delta_in_ms > REFRESH_INDEX_DELAY_WARNING_IN_MS) {
+				if (advice_enabled(ADVICE_RESET_QUIET_WARNING) && t_delta_in_ms > REFRESH_INDEX_DELAY_WARNING_IN_MS) {
 					printf(_("\nIt took %.2f seconds to enumerate unstaged changes after reset.  You can\n"
 						"use '--quiet' to avoid this.  Set the config setting reset.quiet to true\n"
 						"to make this the default.\n"), t_delta_in_ms / 1000.0);
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 22c4e1a..8480a59 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -863,8 +863,8 @@
 				continue;
 			}
 			if (!strcmp(arg, "--bisect")) {
-				for_each_fullref_in("refs/bisect/bad", show_reference, NULL, 0);
-				for_each_fullref_in("refs/bisect/good", anti_reference, NULL, 0);
+				for_each_fullref_in("refs/bisect/bad", show_reference, NULL);
+				for_each_fullref_in("refs/bisect/good", anti_reference, NULL);
 				continue;
 			}
 			if (opt_with_value(arg, "--branches", &arg)) {
diff --git a/builtin/revert.c b/builtin/revert.c
index 237f2f1..51776ab 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -136,6 +136,9 @@
 			PARSE_OPT_KEEP_ARGV0 |
 			PARSE_OPT_KEEP_UNKNOWN);
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	/* implies allow_empty */
 	if (opts->keep_redundant_commits)
 		opts->allow_empty = 1;
@@ -191,7 +194,8 @@
 		struct setup_revision_opt s_r_opt;
 		opts->revs = xmalloc(sizeof(*opts->revs));
 		repo_init_revisions(the_repository, opts->revs, NULL);
-		opts->revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
+		opts->revs->no_walk = 1;
+		opts->revs->unsorted_input = 1;
 		if (argc < 2)
 			usage_with_options(usage_str, options);
 		if (!strcmp(argv[1], "-"))
diff --git a/builtin/rm.c b/builtin/rm.c
index 8a24c71..3d0967c 100644
--- a/builtin/rm.c
+++ b/builtin/rm.c
@@ -55,7 +55,7 @@
 			strbuf_addf(&err_msg,
 				    "\n    %s",
 				    files_list->items[i].string);
-		if (advice_rm_hints)
+		if (advice_enabled(ADVICE_RM_HINTS))
 			strbuf_addstr(&err_msg, hints_msg);
 		*errs = error("%s", err_msg.buf);
 		strbuf_release(&err_msg);
@@ -237,6 +237,7 @@
 
 static int show_only = 0, force = 0, index_only = 0, recursive = 0, quiet = 0;
 static int ignore_unmatch = 0, pathspec_file_nul;
+static int include_sparse;
 static char *pathspec_from_file;
 
 static struct option builtin_rm_options[] = {
@@ -247,6 +248,7 @@
 	OPT_BOOL('r', NULL,             &recursive,  N_("allow recursive removal")),
 	OPT_BOOL( 0 , "ignore-unmatch", &ignore_unmatch,
 				N_("exit with a zero status even if nothing matched")),
+	OPT_BOOL(0, "sparse", &include_sparse, N_("allow updating entries outside of the sparse-checkout cone")),
 	OPT_PATHSPEC_FROM_FILE(&pathspec_from_file),
 	OPT_PATHSPEC_FILE_NUL(&pathspec_file_nul),
 	OPT_END(),
@@ -298,7 +300,10 @@
 	ensure_full_index(&the_index);
 	for (i = 0; i < active_nr; i++) {
 		const struct cache_entry *ce = active_cache[i];
-		if (ce_skip_worktree(ce))
+
+		if (!include_sparse &&
+		    (ce_skip_worktree(ce) ||
+		     !path_in_sparse_checkout(ce->name, &the_index)))
 			continue;
 		if (!ce_path_match(&the_index, ce, &pathspec, seen))
 			continue;
@@ -322,7 +327,8 @@
 				seen_any = 1;
 			else if (ignore_unmatch)
 				continue;
-			else if (matches_skip_worktree(&pathspec, i, &skip_worktree_seen))
+			else if (!include_sparse &&
+				 matches_skip_worktree(&pathspec, i, &skip_worktree_seen))
 				string_list_append(&only_match_skip_worktree, original);
 			else
 				die(_("pathspec '%s' did not match any files"), original);
diff --git a/builtin/send-pack.c b/builtin/send-pack.c
index 729dea1..69c432e 100644
--- a/builtin/send-pack.c
+++ b/builtin/send-pack.c
@@ -17,10 +17,10 @@
 #include "protocol.h"
 
 static const char * const send_pack_usage[] = {
-	N_("git send-pack [--all | --mirror] [--dry-run] [--force] "
-	  "[--receive-pack=<git-receive-pack>] [--verbose] [--thin] [--atomic] "
-	  "[<host>:]<directory> [<ref>...]\n"
-	  "  --all and explicit <ref> specification are mutually exclusive."),
+	N_("git send-pack [--mirror] [--dry-run] [--force]\n"
+	   "              [--receive-pack=<git-receive-pack>]\n"
+	   "              [--verbose] [--thin] [--atomic]\n"
+	   "              [<host>:]<directory> (--all | <ref>...)"),
 	NULL,
 };
 
@@ -87,6 +87,10 @@
 			break;
 
 		case REF_STATUS_EXPECTING_REPORT:
+			res = "error";
+			msg = "expecting report";
+			break;
+
 		default:
 			continue;
 		}
diff --git a/builtin/shortlog.c b/builtin/shortlog.c
index 3e7ab1c..e7f7af5 100644
--- a/builtin/shortlog.c
+++ b/builtin/shortlog.c
@@ -374,6 +374,9 @@
 
 	for (;;) {
 		switch (parse_options_step(&ctx, options, shortlog_usage)) {
+		case PARSE_OPT_NON_OPTION:
+		case PARSE_OPT_UNKNOWN:
+			break;
 		case PARSE_OPT_HELP:
 		case PARSE_OPT_ERROR:
 			exit(129);
diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index bea4bbf..0824492 100644
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -11,9 +11,9 @@
 
 static const char* show_branch_usage[] = {
     N_("git show-branch [-a | --all] [-r | --remotes] [--topo-order | --date-order]\n"
-       "		[--current] [--color[=<when>] | --no-color] [--sparse]\n"
-       "		[--more=<n> | --list | --independent | --merge-base]\n"
-       "		[--no-name | --sha1-name] [--topics] [(<rev> | <glob>)...]"),
+       "                [--current] [--color[=<when>] | --no-color] [--sparse]\n"
+       "                [--more=<n> | --list | --independent | --merge-base]\n"
+       "                [--no-name | --sha1-name] [--topics] [(<rev> | <glob>)...]"),
     N_("git show-branch (-g | --reflog)[=<n>[,<base>]] [--list] [<ref>]"),
     NULL
 };
diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index 8ba9f13..d0f5c47 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -100,6 +100,98 @@
 	return 0;
 }
 
+static void clean_tracked_sparse_directories(struct repository *r)
+{
+	int i, was_full = 0;
+	struct strbuf path = STRBUF_INIT;
+	size_t pathlen;
+	struct string_list_item *item;
+	struct string_list sparse_dirs = STRING_LIST_INIT_DUP;
+
+	/*
+	 * If we are not using cone mode patterns, then we cannot
+	 * delete directories outside of the sparse cone.
+	 */
+	if (!r || !r->index || !r->worktree)
+		return;
+	if (init_sparse_checkout_patterns(r->index) ||
+	    !r->index->sparse_checkout_patterns->use_cone_patterns)
+		return;
+
+	/*
+	 * Use the sparse index as a data structure to assist finding
+	 * directories that are safe to delete. This conversion to a
+	 * sparse index will not delete directories that contain
+	 * conflicted entries or submodules.
+	 */
+	if (!r->index->sparse_index) {
+		/*
+		 * If something, such as a merge conflict or other concern,
+		 * prevents us from converting to a sparse index, then do
+		 * not try deleting files.
+		 */
+		if (convert_to_sparse(r->index, SPARSE_INDEX_MEMORY_ONLY))
+			return;
+		was_full = 1;
+	}
+
+	strbuf_addstr(&path, r->worktree);
+	strbuf_complete(&path, '/');
+	pathlen = path.len;
+
+	/*
+	 * Collect directories that have gone out of scope but also
+	 * exist on disk, so there is some work to be done. We need to
+	 * store the entries in a list before exploring, since that might
+	 * expand the sparse-index again.
+	 */
+	for (i = 0; i < r->index->cache_nr; i++) {
+		struct cache_entry *ce = r->index->cache[i];
+
+		if (S_ISSPARSEDIR(ce->ce_mode) &&
+		    repo_file_exists(r, ce->name))
+			string_list_append(&sparse_dirs, ce->name);
+	}
+
+	for_each_string_list_item(item, &sparse_dirs) {
+		struct dir_struct dir = DIR_INIT;
+		struct pathspec p = { 0 };
+		struct strvec s = STRVEC_INIT;
+
+		strbuf_setlen(&path, pathlen);
+		strbuf_addstr(&path, item->string);
+
+		dir.flags |= DIR_SHOW_IGNORED_TOO;
+
+		setup_standard_excludes(&dir);
+		strvec_push(&s, path.buf);
+
+		parse_pathspec(&p, PATHSPEC_GLOB, 0, NULL, s.v);
+		fill_directory(&dir, r->index, &p);
+
+		if (dir.nr) {
+			warning(_("directory '%s' contains untracked files,"
+				  " but is not in the sparse-checkout cone"),
+				item->string);
+		} else if (remove_dir_recursively(&path, 0)) {
+			/*
+			 * Removal is "best effort". If something blocks
+			 * the deletion, then continue with a warning.
+			 */
+			warning(_("failed to remove directory '%s'"),
+				item->string);
+		}
+
+		dir_clear(&dir);
+	}
+
+	string_list_clear(&sparse_dirs, 0);
+	strbuf_release(&path);
+
+	if (was_full)
+		ensure_full_index(r->index);
+}
+
 static int update_working_directory(struct pattern_list *pl)
 {
 	enum update_sparsity_result result;
@@ -141,6 +233,8 @@
 	else
 		rollback_lock_file(&lock_file);
 
+	clean_tracked_sparse_directories(r);
+
 	r->index->sparse_checkout_patterns = NULL;
 	return result;
 }
diff --git a/builtin/stash.c b/builtin/stash.c
index 5512f49..a0ccc86 100644
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -85,7 +85,7 @@
 
 static const char * const git_stash_save_usage[] = {
 	N_("git stash save [-p|--patch] [-k|--[no-]keep-index] [-q|--quiet]\n"
-	   "          [-u|--include-untracked] [-a|--all] [<message>]"),
+	   "               [-u|--include-untracked] [-a|--all] [<message>]"),
 	NULL
 };
 
@@ -256,8 +256,10 @@
 	opts.src_index = &the_index;
 	opts.dst_index = &the_index;
 	opts.merge = 1;
-	opts.reset = reset;
+	opts.reset = reset ? UNPACK_RESET_PROTECT_UNTRACKED : 0;
 	opts.update = update;
+	if (update)
+		opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
 	opts.fn = oneway_merge;
 
 	if (unpack_trees(nr_trees, t, &opts))
@@ -1533,6 +1535,7 @@
 		} else {
 			struct child_process cp = CHILD_PROCESS_INIT;
 			cp.git_cmd = 1;
+			/* BUG: this nukes untracked files in the way */
 			strvec_pushl(&cp.args, "reset", "--hard", "-q",
 				     "--no-recurse-submodules", NULL);
 			if (run_command(&cp)) {
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index ef2776a..e630f0c 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -199,34 +199,28 @@
 	return strbuf_detach(&sb, NULL);
 }
 
-static int resolve_relative_url(int argc, const char **argv, const char *prefix)
+static char *resolve_relative_url(const char *rel_url, const char *up_path, int quiet)
 {
-	char *remoteurl = NULL;
+	char *remoteurl, *resolved_url;
 	char *remote = get_default_remote();
-	const char *up_path = NULL;
-	char *res;
-	const char *url;
-	struct strbuf sb = STRBUF_INIT;
+	struct strbuf remotesb = STRBUF_INIT;
 
-	if (argc != 2 && argc != 3)
-		die("resolve-relative-url only accepts one or two arguments");
-
-	url = argv[1];
-	strbuf_addf(&sb, "remote.%s.url", remote);
-	free(remote);
-
-	if (git_config_get_string(sb.buf, &remoteurl))
-		/* the repository is its own authoritative upstream */
+	strbuf_addf(&remotesb, "remote.%s.url", remote);
+	if (git_config_get_string(remotesb.buf, &remoteurl)) {
+		if (!quiet)
+			warning(_("could not look up configuration '%s'. "
+				  "Assuming this repository is its own "
+				  "authoritative upstream."),
+				remotesb.buf);
 		remoteurl = xgetcwd();
+	}
+	resolved_url = relative_url(remoteurl, rel_url, up_path);
 
-	if (argc == 3)
-		up_path = argv[2];
-
-	res = relative_url(remoteurl, url, up_path);
-	puts(res);
-	free(res);
+	free(remote);
 	free(remoteurl);
-	return 0;
+	strbuf_release(&remotesb);
+
+	return resolved_url;
 }
 
 static int resolve_relative_url_test(int argc, const char **argv, const char *prefix)
@@ -313,7 +307,7 @@
 	const struct cache_entry **entries;
 	int alloc, nr;
 };
-#define MODULE_LIST_INIT { NULL, 0, 0 }
+#define MODULE_LIST_INIT { 0 }
 
 static int module_list_compute(int argc, const char **argv,
 			       const char *prefix,
@@ -590,31 +584,11 @@
 	return 0;
 }
 
-static char *compute_submodule_clone_url(const char *rel_url)
-{
-	char *remoteurl, *relurl;
-	char *remote = get_default_remote();
-	struct strbuf remotesb = STRBUF_INIT;
-
-	strbuf_addf(&remotesb, "remote.%s.url", remote);
-	if (git_config_get_string(remotesb.buf, &remoteurl)) {
-		warning(_("could not look up configuration '%s'. Assuming this repository is its own authoritative upstream."), remotesb.buf);
-		remoteurl = xgetcwd();
-	}
-	relurl = relative_url(remoteurl, rel_url, NULL);
-
-	free(remote);
-	free(remoteurl);
-	strbuf_release(&remotesb);
-
-	return relurl;
-}
-
 struct init_cb {
 	const char *prefix;
 	unsigned int flags;
 };
-#define INIT_CB_INIT { NULL, 0 }
+#define INIT_CB_INIT { 0 }
 
 static void init_submodule(const char *path, const char *prefix,
 			   unsigned int flags)
@@ -660,7 +634,7 @@
 		if (starts_with_dot_dot_slash(url) ||
 		    starts_with_dot_slash(url)) {
 			char *oldurl = url;
-			url = compute_submodule_clone_url(oldurl);
+			url = resolve_relative_url(oldurl, NULL, 0);
 			free(oldurl);
 		}
 
@@ -743,7 +717,7 @@
 	const char *prefix;
 	unsigned int flags;
 };
-#define STATUS_CB_INIT { NULL, 0 }
+#define STATUS_CB_INIT { 0 }
 
 static void print_status(unsigned int flags, char state, const char *path,
 			 const struct object_id *oid, const char *displaypath)
@@ -937,13 +911,13 @@
 	char status;
 	const char *sm_path;
 };
-#define MODULE_CB_INIT { 0, 0, NULL, NULL, '\0', NULL }
+#define MODULE_CB_INIT { 0 }
 
 struct module_cb_list {
 	struct module_cb **entries;
 	int alloc, nr;
 };
-#define MODULE_CB_LIST_INIT { NULL, 0, 0 }
+#define MODULE_CB_LIST_INIT { 0 }
 
 struct summary_cb {
 	int argc;
@@ -954,7 +928,7 @@
 	unsigned int files: 1;
 	int summary_limit;
 };
-#define SUMMARY_CB_INIT { 0, NULL, NULL, 0, 0, 0, 0 }
+#define SUMMARY_CB_INIT { 0 }
 
 enum diff_cmd {
 	DIFF_INDEX,
@@ -1360,7 +1334,7 @@
 	const char *prefix;
 	unsigned int flags;
 };
-#define SYNC_CB_INIT { NULL, 0 }
+#define SYNC_CB_INIT { 0 }
 
 static void sync_submodule(const char *path, const char *prefix,
 			   unsigned int flags)
@@ -1380,20 +1354,10 @@
 	if (sub && sub->url) {
 		if (starts_with_dot_dot_slash(sub->url) ||
 		    starts_with_dot_slash(sub->url)) {
-			char *remote_url, *up_path;
-			char *remote = get_default_remote();
-			strbuf_addf(&sb, "remote.%s.url", remote);
-
-			if (git_config_get_string(sb.buf, &remote_url))
-				remote_url = xgetcwd();
-
-			up_path = get_up_path(path);
-			sub_origin_url = relative_url(remote_url, sub->url, up_path);
-			super_config_url = relative_url(remote_url, sub->url, NULL);
-
-			free(remote);
+			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);
-			free(remote_url);
 		} else {
 			sub_origin_url = xstrdup(sub->url);
 			super_config_url = xstrdup(sub->url);
@@ -1516,7 +1480,7 @@
 	const char *prefix;
 	unsigned int flags;
 };
-#define DEINIT_CB_INIT { NULL, 0 }
+#define DEINIT_CB_INIT { 0 }
 
 static void deinit_submodule(const char *path, const char *prefix,
 			     unsigned int flags)
@@ -1683,8 +1647,9 @@
 	} error_mode;
 	struct string_list *reference;
 };
-#define SUBMODULE_ALTERNATE_SETUP_INIT { NULL, \
-	SUBMODULE_ALTERNATE_ERROR_IGNORE, NULL }
+#define SUBMODULE_ALTERNATE_SETUP_INIT { \
+	.error_mode = SUBMODULE_ALTERNATE_ERROR_IGNORE, \
+}
 
 static const char alternate_error_advice[] = N_(
 "An alternate computed from a superproject's alternate is invalid.\n"
@@ -1704,18 +1669,24 @@
 	 * standard layout with .git/(modules/<name>)+/objects
 	 */
 	if (strip_suffix(odb->path, "/objects", &len)) {
+		struct repository alternate;
 		char *sm_alternate;
 		struct strbuf sb = STRBUF_INIT;
 		struct strbuf err = STRBUF_INIT;
 		strbuf_add(&sb, odb->path, len);
 
+		repo_init(&alternate, sb.buf, NULL);
+
 		/*
 		 * We need to end the new path with '/' to mark it as a dir,
 		 * otherwise a submodule name containing '/' will be broken
 		 * as the last part of a missing submodule reference would
 		 * be taken as a file name.
 		 */
-		strbuf_addf(&sb, "/modules/%s/", sas->submodule_name);
+		strbuf_reset(&sb);
+		submodule_name_to_gitdir(&sb, &alternate, sas->submodule_name);
+		strbuf_addch(&sb, '/');
+		repo_clear(&alternate);
 
 		sm_alternate = compute_alternate_path(sb.buf, &err);
 		if (sm_alternate) {
@@ -1724,7 +1695,7 @@
 		} else {
 			switch (sas->error_mode) {
 			case SUBMODULE_ALTERNATE_ERROR_DIE:
-				if (advice_submodule_alternate_error_strategy_die)
+				if (advice_enabled(ADVICE_SUBMODULE_ALTERNATE_ERROR_STRATEGY_DIE))
 					advise(_(alternate_error_advice));
 				die(_("submodule '%s' cannot add alternate: %s"),
 				    sas->submodule_name, err.buf);
@@ -1785,7 +1756,7 @@
 	struct strbuf sb = STRBUF_INIT;
 	struct child_process cp = CHILD_PROCESS_INIT;
 
-	strbuf_addf(&sb, "%s/modules/%s", get_git_dir(), clone_data->name);
+	submodule_name_to_gitdir(&sb, the_repository, clone_data->name);
 	sm_gitdir = absolute_pathdup(sb.buf);
 	strbuf_reset(&sb);
 
@@ -2045,6 +2016,20 @@
 	.max_jobs = 1, \
 }
 
+struct update_data {
+	const char *recursive_prefix;
+	const char *sm_path;
+	const char *displaypath;
+	struct object_id oid;
+	struct object_id suboid;
+	struct submodule_update_strategy update_strategy;
+	int depth;
+	unsigned int force: 1;
+	unsigned int quiet: 1;
+	unsigned int nofetch: 1;
+	unsigned int just_cloned: 1;
+};
+#define UPDATE_DATA_INIT { .update_strategy = SUBMODULE_UPDATE_STRATEGY_INIT }
 
 static void next_submodule_warn_missing(struct submodule_update_clone *suc,
 		struct strbuf *out, const char *displaypath)
@@ -2134,7 +2119,7 @@
 	if (repo_config_get_string_tmp(the_repository, sb.buf, &url)) {
 		if (starts_with_dot_slash(sub->url) ||
 		    starts_with_dot_dot_slash(sub->url)) {
-			url = compute_submodule_clone_url(sub->url);
+			url = resolve_relative_url(sub->url, NULL, 0);
 			need_free_url = 1;
 		} else
 			url = sub->url;
@@ -2298,6 +2283,181 @@
 	return 0;
 }
 
+static int is_tip_reachable(const char *path, 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.no_stderr = 1;
+	strvec_pushl(&cp.args, "rev-list", "-n", "1", hex, "--not", "--all", NULL);
+
+	prepare_submodule_repo_env(&cp.env_array);
+
+	if (capture_command(&cp, &rev, GIT_MAX_HEXSZ + 1) || rev.len)
+		return 0;
+
+	return 1;
+}
+
+static int fetch_in_submodule(const char *module_path, int depth, int quiet, struct object_id *oid)
+{
+	struct child_process cp = CHILD_PROCESS_INIT;
+
+	prepare_submodule_repo_env(&cp.env_array);
+	cp.git_cmd = 1;
+	cp.dir = xstrdup(module_path);
+
+	strvec_push(&cp.args, "fetch");
+	if (quiet)
+		strvec_push(&cp.args, "--quiet");
+	if (depth)
+		strvec_pushf(&cp.args, "--depth=%d", depth);
+	if (oid) {
+		char *hex = oid_to_hex(oid);
+		char *remote = get_default_remote();
+		strvec_pushl(&cp.args, remote, hex, NULL);
+	}
+
+	return run_command(&cp);
+}
+
+static int run_update_command(struct update_data *ud, int subforce)
+{
+	struct strvec args = STRVEC_INIT;
+	struct strvec child_env = STRVEC_INIT;
+	char *oid = oid_to_hex(&ud->oid);
+	int must_die_on_failure = 0;
+	int git_cmd;
+
+	switch (ud->update_strategy.type) {
+	case SM_UPDATE_CHECKOUT:
+		git_cmd = 1;
+		strvec_pushl(&args, "checkout", "-q", NULL);
+		if (subforce)
+			strvec_push(&args, "-f");
+		break;
+	case SM_UPDATE_REBASE:
+		git_cmd = 1;
+		strvec_push(&args, "rebase");
+		if (ud->quiet)
+			strvec_push(&args, "--quiet");
+		must_die_on_failure = 1;
+		break;
+	case SM_UPDATE_MERGE:
+		git_cmd = 1;
+		strvec_push(&args, "merge");
+		if (ud->quiet)
+			strvec_push(&args, "--quiet");
+		must_die_on_failure = 1;
+		break;
+	case SM_UPDATE_COMMAND:
+		git_cmd = 0;
+		strvec_push(&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));
+	}
+	strvec_push(&args, oid);
+
+	prepare_submodule_repo_env(&child_env);
+	if (run_command_v_opt_cd_env(args.v, git_cmd ? RUN_GIT_CMD : RUN_USING_SHELL,
+				     ud->sm_path, child_env.v)) {
+		switch (ud->update_strategy.type) {
+		case SM_UPDATE_CHECKOUT:
+			printf(_("Unable to checkout '%s' in submodule path '%s'"),
+			       oid, ud->displaypath);
+			break;
+		case SM_UPDATE_REBASE:
+			printf(_("Unable to rebase '%s' in submodule path '%s'"),
+			       oid, ud->displaypath);
+			break;
+		case SM_UPDATE_MERGE:
+			printf(_("Unable to merge '%s' in submodule path '%s'"),
+			       oid, ud->displaypath);
+			break;
+		case SM_UPDATE_COMMAND:
+			printf(_("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));
+		}
+		/*
+		 * NEEDSWORK: We are currently printing to stdout with error
+		 * return so that the shell caller handles the error output
+		 * properly. Once we start handling the error messages within
+		 * C, we should use die() instead.
+		 */
+		if (must_die_on_failure)
+			return 2;
+		/*
+		 * This signifies to the caller in shell that the command
+		 * failed without dying
+		 */
+		return 1;
+	}
+
+	switch (ud->update_strategy.type) {
+	case SM_UPDATE_CHECKOUT:
+		printf(_("Submodule path '%s': checked out '%s'\n"),
+		       ud->displaypath, oid);
+		break;
+	case SM_UPDATE_REBASE:
+		printf(_("Submodule path '%s': rebased into '%s'\n"),
+		       ud->displaypath, oid);
+		break;
+	case SM_UPDATE_MERGE:
+		printf(_("Submodule path '%s': merged in '%s'\n"),
+		       ud->displaypath, oid);
+		break;
+	case SM_UPDATE_COMMAND:
+		printf(_("Submodule path '%s': '%s %s'\n"),
+		       ud->displaypath, ud->update_strategy.command, oid);
+		break;
+	default:
+		BUG("unexpected update strategy type: %s",
+		    submodule_strategy_to_string(&ud->update_strategy));
+	}
+
+	return 0;
+}
+
+static int do_run_update_procedure(struct update_data *ud)
+{
+	int subforce = is_null_oid(&ud->suboid) || ud->force;
+
+	if (!ud->nofetch) {
+		/*
+		 * Run fetch only if `oid` isn't present or it
+		 * is not reachable from a ref.
+		 */
+		if (!is_tip_reachable(ud->sm_path, &ud->oid) &&
+		    fetch_in_submodule(ud->sm_path, ud->depth, ud->quiet, NULL) &&
+		    !ud->quiet)
+			fprintf_ln(stderr,
+				   _("Unable to fetch in submodule path '%s'; "
+				     "trying to directly fetch %s:"),
+				   ud->displaypath, oid_to_hex(&ud->oid));
+		/*
+		 * Now we tried the usual fetch, but `oid` may
+		 * not be reachable from any of the refs.
+		 */
+		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 run_update_command(ud, subforce);
+}
+
 static void update_submodule(struct update_clone_data *ucd)
 {
 	fprintf(stdout, "dummy %s %d\t%s\n",
@@ -2395,6 +2555,73 @@
 	return update_submodules(&suc);
 }
 
+static int run_update_procedure(int argc, const char **argv, const char *prefix)
+{
+	int force = 0, quiet = 0, nofetch = 0, just_cloned = 0;
+	char *prefixed_path, *update = NULL;
+	struct update_data update_data = UPDATE_DATA_INIT;
+
+	struct option options[] = {
+		OPT__QUIET(&quiet, N_("suppress output for update by rebase or merge")),
+		OPT__FORCE(&force, N_("force checkout updates"), 0),
+		OPT_BOOL('N', "no-fetch", &nofetch,
+			 N_("don't fetch new objects from the remote site")),
+		OPT_BOOL(0, "just-cloned", &just_cloned,
+			 N_("overrides update mode in case the repository is a fresh clone")),
+		OPT_INTEGER(0, "depth", &update_data.depth, N_("depth for shallow fetch")),
+		OPT_STRING(0, "prefix", &prefix,
+			   N_("path"),
+			   N_("path into the working tree")),
+		OPT_STRING(0, "update", &update,
+			   N_("string"),
+			   N_("rebase, merge, checkout or none")),
+		OPT_STRING(0, "recursive-prefix", &update_data.recursive_prefix, N_("path"),
+			   N_("path into the working tree, across nested "
+			      "submodule boundaries")),
+		OPT_CALLBACK_F(0, "oid", &update_data.oid, N_("sha1"),
+			       N_("SHA1 expected by superproject"), PARSE_OPT_NONEG,
+			       parse_opt_object_id),
+		OPT_CALLBACK_F(0, "suboid", &update_data.suboid, N_("subsha1"),
+			       N_("SHA1 of submodule's HEAD"), PARSE_OPT_NONEG,
+			       parse_opt_object_id),
+		OPT_END()
+	};
+
+	const char *const usage[] = {
+		N_("git submodule--helper run-update-procedure [<options>] <path>"),
+		NULL
+	};
+
+	argc = parse_options(argc, argv, prefix, options, usage, 0);
+
+	if (argc != 1)
+		usage_with_options(usage, options);
+
+	update_data.force = !!force;
+	update_data.quiet = !!quiet;
+	update_data.nofetch = !!nofetch;
+	update_data.just_cloned = !!just_cloned;
+	update_data.sm_path = argv[0];
+
+	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, prefix);
+
+	determine_submodule_update_strategy(the_repository, update_data.just_cloned,
+					    update_data.sm_path, update,
+					    &update_data.update_strategy);
+
+	free(prefixed_path);
+
+	if (!oideq(&update_data.oid, &update_data.suboid) || update_data.force)
+		return do_run_update_procedure(&update_data);
+
+	return 3;
+}
+
 static int resolve_relative_path(int argc, const char **argv, const char *prefix)
 {
 	struct strbuf sb = STRBUF_INIT;
@@ -2540,7 +2767,6 @@
 
 static int ensure_core_worktree(int argc, const char **argv, const char *prefix)
 {
-	const struct submodule *sub;
 	const char *path;
 	const char *cw;
 	struct repository subrepo;
@@ -2550,11 +2776,7 @@
 
 	path = argv[1];
 
-	sub = submodule_from_path(the_repository, null_oid(), path);
-	if (!sub)
-		BUG("We could get the submodule handle before?");
-
-	if (repo_submodule_init(&subrepo, the_repository, sub))
+	if (repo_submodule_init(&subrepo, the_repository, path, null_oid()))
 		die(_("could not get a repository handle for submodule '%s'"), path);
 
 	if (!repo_config_get_string_tmp(&subrepo, "core.worktree", &cw)) {
@@ -2765,7 +2987,7 @@
 	const char *prefix;
 	const char *branch;
 	const char *reference_path;
-	const char *sm_path;
+	char *sm_path;
 	const char *sm_name;
 	const char *repo;
 	const char *realrepo;
@@ -2777,7 +2999,7 @@
 };
 #define ADD_DATA_INIT { .depth = -1 }
 
-static void show_fetch_remotes(FILE *output, const char *git_dir_path)
+static void append_fetch_remotes(struct strbuf *msg, const char *git_dir_path)
 {
 	struct child_process cp_remote = CHILD_PROCESS_INIT;
 	struct strbuf sb_remote_out = STRBUF_INIT;
@@ -2793,7 +3015,7 @@
 		while ((next_line = strchr(line, '\n')) != NULL) {
 			size_t len = next_line - line;
 			if (strip_suffix_mem(line, &len, " (fetch)"))
-				fprintf(output, "  %.*s\n", (int)len, line);
+				strbuf_addf(msg, "  %.*s\n", (int)len, line);
 			line = next_line + 1;
 		}
 	}
@@ -2825,19 +3047,27 @@
 
 		if (is_directory(submod_gitdir_path)) {
 			if (!add_data->force) {
-				fprintf(stderr, _("A git directory for '%s' is found "
-						  "locally with remote(s):"),
-					add_data->sm_name);
-				show_fetch_remotes(stderr, submod_gitdir_path);
+				struct strbuf msg = STRBUF_INIT;
+				char *die_msg;
+
+				strbuf_addf(&msg, _("A git directory for '%s' is found "
+						    "locally with remote(s):\n"),
+					    add_data->sm_name);
+
+				append_fetch_remotes(&msg, submod_gitdir_path);
 				free(submod_gitdir_path);
-				die(_("If you want to reuse this local git "
-				      "directory instead of cloning again from\n"
-				      "  %s\n"
-				      "use the '--force' option. If the local git "
-				      "directory is not the correct repo\n"
-				      "or if you are unsure what this means, choose "
-				      "another name with the '--name' option.\n"),
-				    add_data->realrepo);
+
+				strbuf_addf(&msg, _("If you want to reuse this local git "
+						    "directory instead of cloning again from\n"
+						    "  %s\n"
+						    "use the '--force' option. If the local git "
+						    "directory is not the correct repo\n"
+						    "or you are unsure what this means choose "
+						    "another name with the '--name' option."),
+					    add_data->realrepo);
+
+				die_msg = strbuf_detach(&msg, NULL);
+				die("%s", die_msg);
 			} else {
 				printf(_("Reactivating local git directory for "
 					 "submodule '%s'\n"), add_data->sm_name);
@@ -2864,6 +3094,10 @@
 		prepare_submodule_repo_env(&cp.env_array);
 		cp.git_cmd = 1;
 		cp.dir = add_data->sm_path;
+		/*
+		 * NOTE: we only get here if add_data->force is true, so
+		 * passing --force to checkout is reasonable.
+		 */
 		strvec_pushl(&cp.args, "checkout", "-f", "-q", NULL);
 
 		if (add_data->branch) {
@@ -2877,61 +3111,246 @@
 	return 0;
 }
 
-static int add_clone(int argc, const char **argv, const char *prefix)
+static int config_submodule_in_gitmodules(const char *name, const char *var, const char *value)
 {
-	int force = 0, quiet = 0, dissociate = 0, progress = 0;
+	char *key;
+	int ret;
+
+	if (!is_writing_gitmodules_ok())
+		die(_("please make sure that the .gitmodules file is in the working tree"));
+
+	key = xstrfmt("submodule.%s.%s", name, var);
+	ret = config_set_in_gitmodules_file_gently(key, value);
+	free(key);
+
+	return ret;
+}
+
+static void configure_added_submodule(struct add_data *add_data)
+{
+	char *key;
+	char *val = NULL;
+	struct child_process add_submod = CHILD_PROCESS_INIT;
+	struct child_process add_gitmodules = CHILD_PROCESS_INIT;
+
+	key = xstrfmt("submodule.%s.url", add_data->sm_name);
+	git_config_set_gently(key, add_data->realrepo);
+	free(key);
+
+	add_submod.git_cmd = 1;
+	strvec_pushl(&add_submod.args, "add",
+		     "--no-warn-embedded-repo", NULL);
+	if (add_data->force)
+		strvec_push(&add_submod.args, "--force");
+	strvec_pushl(&add_submod.args, "--", add_data->sm_path, NULL);
+
+	if (run_command(&add_submod))
+		die(_("Failed to add submodule '%s'"), add_data->sm_path);
+
+	if (config_submodule_in_gitmodules(add_data->sm_name, "path", add_data->sm_path) ||
+	    config_submodule_in_gitmodules(add_data->sm_name, "url", add_data->repo))
+		die(_("Failed to register submodule '%s'"), add_data->sm_path);
+
+	if (add_data->branch) {
+		if (config_submodule_in_gitmodules(add_data->sm_name,
+						   "branch", add_data->branch))
+			die(_("Failed to register submodule '%s'"), add_data->sm_path);
+	}
+
+	add_gitmodules.git_cmd = 1;
+	strvec_pushl(&add_gitmodules.args,
+		     "add", "--force", "--", ".gitmodules", NULL);
+
+	if (run_command(&add_gitmodules))
+		die(_("Failed to register submodule '%s'"), add_data->sm_path);
+
+	/*
+	 * NEEDSWORK: In a multi-working-tree world this needs to be
+	 * set in the per-worktree config.
+	 */
+	/*
+	 * NEEDSWORK: In the longer run, we need to get rid of this
+	 * pattern of querying "submodule.active" before calling
+	 * 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 the submodule being added isn't already covered by the
+		 * current configured pathspec, set the submodule's active flag
+		 */
+		if (!is_submodule_active(the_repository, add_data->sm_path)) {
+			key = xstrfmt("submodule.%s.active", add_data->sm_name);
+			git_config_set_gently(key, "true");
+			free(key);
+		}
+	} else {
+		key = xstrfmt("submodule.%s.active", add_data->sm_name);
+		git_config_set_gently(key, "true");
+		free(key);
+	}
+}
+
+static void die_on_index_match(const char *path, int force)
+{
+	struct pathspec ps;
+	const char *args[] = { path, NULL };
+	parse_pathspec(&ps, 0, PATHSPEC_PREFER_CWD, NULL, args);
+
+	if (read_cache_preload(NULL) < 0)
+		die(_("index file corrupt"));
+
+	if (ps.nr) {
+		int i;
+		char *ps_matched = xcalloc(ps.nr, 1);
+
+		/* TODO: audit for interaction with sparse-index. */
+		ensure_full_index(&the_index);
+
+		/*
+		 * Since there is only one pathspec, we just need
+		 * need to check ps_matched[0] to know if a cache
+		 * entry matched.
+		 */
+		for (i = 0; i < active_nr; i++) {
+			ce_path_match(&the_index, active_cache[i], &ps,
+				      ps_matched);
+
+			if (ps_matched[0]) {
+				if (!force)
+					die(_("'%s' already exists in the index"),
+					    path);
+				if (!S_ISGITLINK(active_cache[i]->ce_mode))
+					die(_("'%s' already exists in the index "
+					      "and is not a submodule"), path);
+				break;
+			}
+		}
+		free(ps_matched);
+	}
+	clear_pathspec(&ps);
+}
+
+static void die_on_repo_without_commits(const char *path)
+{
+	struct strbuf sb = STRBUF_INIT;
+	strbuf_addstr(&sb, path);
+	if (is_nonbare_repository_dir(&sb)) {
+		struct object_id oid;
+		if (resolve_gitlink_ref(path, "HEAD", &oid) < 0)
+			die(_("'%s' does not have a commit checked out"), path);
+	}
+	strbuf_release(&sb);
+}
+
+static int module_add(int argc, const char **argv, const char *prefix)
+{
+	int force = 0, quiet = 0, progress = 0, dissociate = 0;
 	struct add_data add_data = ADD_DATA_INIT;
 
 	struct option options[] = {
-		OPT_STRING('b', "branch", &add_data.branch,
-			   N_("branch"),
-			   N_("branch of repository to checkout on cloning")),
-		OPT_STRING(0, "prefix", &prefix,
-			   N_("path"),
-			   N_("alternative anchor for relative paths")),
-		OPT_STRING(0, "path", &add_data.sm_path,
-			   N_("path"),
-			   N_("where the new submodule will be cloned to")),
-		OPT_STRING(0, "name", &add_data.sm_name,
-			   N_("string"),
-			   N_("name of the new submodule")),
-		OPT_STRING(0, "url", &add_data.realrepo,
-			   N_("string"),
-			   N_("url where to clone the submodule from")),
-		OPT_STRING(0, "reference", &add_data.reference_path,
-			   N_("repo"),
-			   N_("reference repository")),
-		OPT_BOOL(0, "dissociate", &dissociate,
-			 N_("use --reference only while cloning")),
-		OPT_INTEGER(0, "depth", &add_data.depth,
-			    N_("depth for shallow clones")),
-		OPT_BOOL(0, "progress", &progress,
-			 N_("force cloning progress")),
+		OPT_STRING('b', "branch", &add_data.branch, N_("branch"),
+			   N_("branch of repository to add as submodule")),
 		OPT__FORCE(&force, N_("allow adding an otherwise ignored submodule path"),
 			   PARSE_OPT_NOCOMPLETE),
-		OPT__QUIET(&quiet, "suppress output for cloning a submodule"),
+		OPT__QUIET(&quiet, N_("print only error messages")),
+		OPT_BOOL(0, "progress", &progress, N_("force cloning progress")),
+		OPT_STRING(0, "reference", &add_data.reference_path, N_("repository"),
+			   N_("reference repository")),
+		OPT_BOOL(0, "dissociate", &dissociate, N_("borrow the objects from reference repositories")),
+		OPT_STRING(0, "name", &add_data.sm_name, N_("name"),
+			   N_("sets the submodule’s name to the given string "
+			      "instead of defaulting to its path")),
+		OPT_INTEGER(0, "depth", &add_data.depth, N_("depth for shallow clones")),
 		OPT_END()
 	};
 
 	const char *const usage[] = {
-		N_("git submodule--helper add-clone [<options>...] "
-		   "--url <url> --path <path> --name <name>"),
+		N_("git submodule--helper add [<options>] [--] <repository> [<path>]"),
 		NULL
 	};
 
 	argc = parse_options(argc, argv, prefix, options, usage, 0);
 
-	if (argc != 0)
+	if (!is_writing_gitmodules_ok())
+		die(_("please make sure that the .gitmodules file is in the working tree"));
+
+	if (prefix && *prefix &&
+	    add_data.reference_path && !is_absolute_path(add_data.reference_path))
+		add_data.reference_path = xstrfmt("%s%s", prefix, add_data.reference_path);
+
+	if (argc == 0 || argc > 2)
 		usage_with_options(usage, options);
 
+	add_data.repo = argv[0];
+	if (argc == 1)
+		add_data.sm_path = git_url_basename(add_data.repo, 0, 0);
+	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 (starts_with_dot_dot_slash(add_data.repo) ||
+	    starts_with_dot_slash(add_data.repo)) {
+		if (prefix)
+			die(_("Relative path can only be used from the toplevel "
+			      "of the working tree"));
+
+		/* dereference source url relative to parent's url */
+		add_data.realrepo = resolve_relative_url(add_data.repo, NULL, 1);
+	} else if (is_dir_sep(add_data.repo[0]) || strchr(add_data.repo, ':')) {
+		add_data.realrepo = add_data.repo;
+	} else {
+		die(_("repo URL: '%s' must be absolute or begin with ./|../"),
+		    add_data.repo);
+	}
+
+	/*
+	 * normalize path:
+	 * multiple //; leading ./; /./; /../;
+	 */
+	normalize_path_copy(add_data.sm_path, add_data.sm_path);
+	strip_dir_trailing_slashes(add_data.sm_path);
+
+	die_on_index_match(add_data.sm_path, force);
+	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))) {
+			strbuf_complete_line(&sb);
+			fputs(sb.buf, stderr);
+			free(add_data.sm_path);
+			return exit_code;
+		}
+		strbuf_release(&sb);
+	}
+
+	if(!add_data.sm_name)
+		add_data.sm_name = add_data.sm_path;
+
+	if (check_submodule_name(add_data.sm_name))
+		die(_("'%s' is not a valid submodule name"), add_data.sm_name);
+
 	add_data.prefix = prefix;
-	add_data.progress = !!progress;
-	add_data.dissociate = !!dissociate;
 	add_data.force = !!force;
 	add_data.quiet = !!quiet;
+	add_data.progress = !!progress;
+	add_data.dissociate = !!dissociate;
 
-	if (add_submodule(&add_data))
+	if (add_submodule(&add_data)) {
+		free(add_data.sm_path);
 		return 1;
+	}
+	configure_added_submodule(&add_data);
+	free(add_data.sm_path);
 
 	return 0;
 }
@@ -2948,12 +3367,12 @@
 	{"list", module_list, 0},
 	{"name", module_name, 0},
 	{"clone", module_clone, 0},
-	{"add-clone", add_clone, 0},
+	{"add", module_add, SUPPORT_SUPER_PREFIX},
 	{"update-module-mode", module_update_module_mode, 0},
 	{"update-clone", update_clone, 0},
+	{"run-update-procedure", run_update_procedure, 0},
 	{"ensure-core-worktree", ensure_core_worktree, 0},
 	{"relative-path", resolve_relative_path, 0},
-	{"resolve-relative-url", resolve_relative_url, 0},
 	{"resolve-relative-url-test", resolve_relative_url_test, 0},
 	{"foreach", module_foreach, SUPPORT_SUPER_PREFIX},
 	{"init", module_init, SUPPORT_SUPER_PREFIX},
diff --git a/builtin/tag.c b/builtin/tag.c
index 87552ae..6fe6467 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -23,10 +23,10 @@
 
 static const char * const git_tag_usage[] = {
 	N_("git tag [-a | -s | -u <key-id>] [-f] [-m <msg> | -F <file>]\n"
-		"\t\t<tagname> [<head>]"),
+	   "        <tagname> [<head>]"),
 	N_("git tag -d <tagname>..."),
 	N_("git tag -l [-n[<num>]] [--contains <commit>] [--no-contains <commit>] [--points-at <object>]\n"
-		"\t\t[--format=<format>] [--merged <commit>] [--no-merged <commit>] [<pattern>...]"),
+	   "        [--format=<format>] [--merged <commit>] [--no-merged <commit>] [<pattern>...]"),
 	N_("git tag -v [--format=<format>] <tagname>..."),
 	NULL
 };
@@ -146,7 +146,7 @@
 		      const struct object_id *oid, void *cb_data)
 {
 	int flags;
-	const struct ref_format *format = cb_data;
+	struct ref_format *format = cb_data;
 	flags = GPG_VERIFY_VERBOSE;
 
 	if (format->format)
@@ -432,7 +432,7 @@
 	int annotate = 0, force = 0;
 	int cmdmode = 0, create_tag_object = 0;
 	const char *msgfile = NULL, *keyid = NULL;
-	struct msg_arg msg = { 0, STRBUF_INIT };
+	struct msg_arg msg = { .buf = STRBUF_INIT };
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
 	struct ref_filter filter;
@@ -482,6 +482,7 @@
 		OPT_BOOL('i', "ignore-case", &icase, N_("sorting and filtering are case insensitive")),
 		OPT_END()
 	};
+	int ret = 0;
 
 	setup_ref_filter_porcelain_msg();
 
@@ -529,7 +530,6 @@
 	ref_sorting_set_sort_flags_all(sorting, REF_SORTING_ICASE, icase);
 	filter.ignore_case = icase;
 	if (cmdmode == 'l') {
-		int ret;
 		if (column_active(colopts)) {
 			struct column_options copts;
 			memset(&copts, 0, sizeof(copts));
@@ -540,7 +540,7 @@
 		ret = list_tags(&filter, sorting, &format);
 		if (column_active(colopts))
 			stop_column_filter();
-		return ret;
+		goto cleanup;
 	}
 	if (filter.lines != -1)
 		die(_("-n option is only allowed in list mode"));
@@ -552,12 +552,15 @@
 		die(_("--points-at option is only allowed in list mode"));
 	if (filter.reachable_from || filter.unreachable_from)
 		die(_("--merged and --no-merged options are only allowed in list mode"));
-	if (cmdmode == 'd')
-		return delete_tags(argv);
+	if (cmdmode == 'd') {
+		ret = delete_tags(argv);
+		goto cleanup;
+	}
 	if (cmdmode == 'v') {
 		if (format.format && verify_ref_format(&format))
 			usage_with_options(git_tag_usage, options);
-		return for_each_tag_name(argv, verify_tag, &format);
+		ret = for_each_tag_name(argv, verify_tag, &format);
+		goto cleanup;
 	}
 
 	if (msg.given || msgfile) {
@@ -626,10 +629,12 @@
 		printf(_("Updated tag '%s' (was %s)\n"), tag,
 		       find_unique_abbrev(&prev, DEFAULT_ABBREV));
 
-	UNLEAK(buf);
-	UNLEAK(ref);
-	UNLEAK(reflog_msg);
-	UNLEAK(msg);
-	UNLEAK(err);
-	return 0;
+cleanup:
+	ref_sorting_release(sorting);
+	strbuf_release(&buf);
+	strbuf_release(&ref);
+	strbuf_release(&reflog_msg);
+	strbuf_release(&msg.buf);
+	strbuf_release(&err);
+	return ret;
 }
diff --git a/builtin/upload-pack.c b/builtin/upload-pack.c
index 6da8fa2..125af53 100644
--- a/builtin/upload-pack.c
+++ b/builtin/upload-pack.c
@@ -16,16 +16,18 @@
 {
 	const char *dir;
 	int strict = 0;
-	struct upload_pack_options opts = { 0 };
-	struct serve_options serve_opts = SERVE_OPTIONS_INIT;
+	int advertise_refs = 0;
+	int stateless_rpc = 0;
+	int timeout = 0;
 	struct option options[] = {
-		OPT_BOOL(0, "stateless-rpc", &opts.stateless_rpc,
+		OPT_BOOL(0, "stateless-rpc", &stateless_rpc,
 			 N_("quit after a single request/response exchange")),
-		OPT_BOOL(0, "advertise-refs", &opts.advertise_refs,
-			 N_("exit immediately after initial ref advertisement")),
+		OPT_HIDDEN_BOOL(0, "http-backend-info-refs", &advertise_refs,
+				N_("serve up the info/refs for git-http-backend")),
+		OPT_ALIAS(0, "advertise-refs", "http-backend-info-refs"),
 		OPT_BOOL(0, "strict", &strict,
 			 N_("do not try <directory>/.git/ if <directory> is no Git directory")),
-		OPT_INTEGER(0, "timeout", &opts.timeout,
+		OPT_INTEGER(0, "timeout", &timeout,
 			    N_("interrupt transfer after <n> seconds of inactivity")),
 		OPT_END()
 	};
@@ -38,9 +40,6 @@
 	if (argc != 1)
 		usage_with_options(upload_pack_usage, options);
 
-	if (opts.timeout)
-		opts.daemon_mode = 1;
-
 	setup_path();
 
 	dir = argv[0];
@@ -50,21 +49,22 @@
 
 	switch (determine_protocol_version_server()) {
 	case protocol_v2:
-		serve_opts.advertise_capabilities = opts.advertise_refs;
-		serve_opts.stateless_rpc = opts.stateless_rpc;
-		serve(&serve_opts);
+		if (advertise_refs)
+			protocol_v2_advertise_capabilities();
+		else
+			protocol_v2_serve_loop(stateless_rpc);
 		break;
 	case protocol_v1:
 		/*
 		 * v1 is just the original protocol with a version string,
 		 * so just fall through after writing the version string.
 		 */
-		if (opts.advertise_refs || !opts.stateless_rpc)
+		if (advertise_refs || !stateless_rpc)
 			packet_write_fmt(1, "version 1\n");
 
 		/* fallthrough */
 	case protocol_v0:
-		upload_pack(&opts);
+		upload_pack(advertise_refs, stateless_rpc, timeout);
 		break;
 	case protocol_unknown_version:
 		BUG("unknown protocol version");
diff --git a/builtin/worktree.c b/builtin/worktree.c
index 0d0a80d..d22ece9 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -8,6 +8,7 @@
 #include "branch.h"
 #include "refs.h"
 #include "run-command.h"
+#include "hook.h"
 #include "sigchain.h"
 #include "submodule.h"
 #include "utf8.h"
diff --git a/bundle.c b/bundle.c
index ab63f40..a0bb687 100644
--- a/bundle.c
+++ b/bundle.c
@@ -569,18 +569,18 @@
 }
 
 int unbundle(struct repository *r, struct bundle_header *header,
-	     int bundle_fd, int flags)
+	     int bundle_fd, struct strvec *extra_index_pack_args)
 {
-	const char *argv_index_pack[] = {"index-pack",
-					 "--fix-thin", "--stdin", NULL, NULL};
 	struct child_process ip = CHILD_PROCESS_INIT;
+	strvec_pushl(&ip.args, "index-pack", "--fix-thin", "--stdin", NULL);
 
-	if (flags & BUNDLE_VERBOSE)
-		argv_index_pack[3] = "-v";
+	if (extra_index_pack_args) {
+		strvec_pushv(&ip.args, extra_index_pack_args->v);
+		strvec_clear(extra_index_pack_args);
+	}
 
 	if (verify_bundle(r, header, 0))
 		return -1;
-	ip.argv = argv_index_pack;
 	ip.in = bundle_fd;
 	ip.no_stdout = 1;
 	ip.git_cmd = 1;
diff --git a/bundle.h b/bundle.h
index 1927d8c..06009fe 100644
--- a/bundle.h
+++ b/bundle.h
@@ -26,9 +26,19 @@
 		  int argc, const char **argv, struct strvec *pack_options,
 		  int version);
 int verify_bundle(struct repository *r, struct bundle_header *header, int verbose);
-#define BUNDLE_VERBOSE 1
+
+/**
+ * Unbundle after reading the header with read_bundle_header().
+ *
+ * We'll invoke "git index-pack --stdin --fix-thin" for you on the
+ * provided `bundle_fd` from read_bundle_header().
+ *
+ * Provide "extra_index_pack_args" to pass any extra arguments
+ * (e.g. "-v" for verbose/progress), NULL otherwise. The provided
+ * "extra_index_pack_args" (if any) will be strvec_clear()'d for you.
+ */
 int unbundle(struct repository *r, struct bundle_header *header,
-	     int bundle_fd, int flags);
+	     int bundle_fd, struct strvec *extra_index_pack_args);
 int list_bundle_refs(struct bundle_header *header,
 		int argc, const char **argv);
 
diff --git a/cache-tree.c b/cache-tree.c
index 90919f9..79d1681 100644
--- a/cache-tree.c
+++ b/cache-tree.c
@@ -440,8 +440,9 @@
 	} else if (dryrun) {
 		hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 				 tree_type, &it->oid);
-	} else if (write_object_file(buffer.buf, buffer.len, tree_type,
-				     &it->oid)) {
+	} else if (write_object_file_flags(buffer.buf, buffer.len, tree_type,
+					   &it->oid, flags & WRITE_TREE_SILENT
+					   ? HASH_SILENT : 0)) {
 		strbuf_release(&buffer);
 		return -1;
 	}
@@ -826,10 +827,17 @@
 		    path->buf);
 }
 
-static void verify_one(struct repository *r,
-		       struct index_state *istate,
-		       struct cache_tree *it,
-		       struct strbuf *path)
+/*
+ * Returns:
+ *  0 - Verification completed.
+ *  1 - Restart verification - a call to ensure_full_index() freed the cache
+ *      tree that is being verified and verification needs to be restarted from
+ *      the new toplevel cache tree.
+ */
+static int verify_one(struct repository *r,
+		      struct index_state *istate,
+		      struct cache_tree *it,
+		      struct strbuf *path)
 {
 	int i, pos, len = path->len;
 	struct strbuf tree_buf = STRBUF_INIT;
@@ -837,21 +845,30 @@
 
 	for (i = 0; i < it->subtree_nr; i++) {
 		strbuf_addf(path, "%s/", it->down[i]->name);
-		verify_one(r, istate, it->down[i]->cache_tree, path);
+		if (verify_one(r, istate, it->down[i]->cache_tree, path))
+			return 1;
 		strbuf_setlen(path, len);
 	}
 
 	if (it->entry_count < 0 ||
 	    /* no verification on tests (t7003) that replace trees */
 	    lookup_replace_object(r, &it->oid) != &it->oid)
-		return;
+		return 0;
 
 	if (path->len) {
+		/*
+		 * If the index is sparse and the cache tree is not
+		 * index_name_pos() may trigger ensure_full_index() which will
+		 * free the tree that is being verified.
+		 */
+		int is_sparse = istate->sparse_index;
 		pos = index_name_pos(istate, path->buf, path->len);
+		if (is_sparse && !istate->sparse_index)
+			return 1;
 
 		if (pos >= 0) {
 			verify_one_sparse(r, istate, it, path, pos);
-			return;
+			return 0;
 		}
 
 		pos = -pos - 1;
@@ -899,6 +916,7 @@
 		    oid_to_hex(&new_oid), oid_to_hex(&it->oid));
 	strbuf_setlen(path, len);
 	strbuf_release(&tree_buf);
+	return 0;
 }
 
 void cache_tree_verify(struct repository *r, struct index_state *istate)
@@ -907,6 +925,10 @@
 
 	if (!istate->cache_tree)
 		return;
-	verify_one(r, istate, istate->cache_tree, &path);
+	if (verify_one(r, istate, istate->cache_tree, &path)) {
+		strbuf_reset(&path);
+		if (verify_one(r, istate, istate->cache_tree, &path))
+			BUG("ensure_full_index() called twice while verifying cache tree");
+	}
 	strbuf_release(&path);
 }
diff --git a/cache.h b/cache.h
index 0a8d44c..eba1248 100644
--- a/cache.h
+++ b/cache.h
@@ -887,6 +887,7 @@
 #define HASH_WRITE_OBJECT 1
 #define HASH_FORMAT_CHECK 2
 #define HASH_RENORMALIZE  4
+#define HASH_SILENT 8
 int index_fd(struct index_state *istate, struct object_id *oid, int fd, struct stat *st, enum object_type type, const char *path, unsigned flags);
 int index_path(struct index_state *istate, struct object_id *oid, const char *path, struct stat *st, unsigned flags);
 
@@ -995,14 +996,6 @@
 extern int core_sparse_checkout_cone;
 
 /*
- * Include broken refs in all ref iterations, which will
- * generally choke dangerous operations rather than letting
- * them silently proceed without taking the broken ref into
- * account.
- */
-extern int ref_paranoia;
-
-/*
  * Returns the boolean value of $GIT_OPTIONAL_LOCKS (or the default value).
  */
 int use_optional_locks(void);
@@ -1210,51 +1203,10 @@
 enum scld_error safe_create_leading_directories_const(const char *path);
 enum scld_error safe_create_leading_directories_no_share(char *path);
 
-/*
- * Callback function for raceproof_create_file(). This function is
- * expected to do something that makes dirname(path) permanent despite
- * the fact that other processes might be cleaning up empty
- * directories at the same time. Usually it will create a file named
- * path, but alternatively it could create another file in that
- * directory, or even chdir() into that directory. The function should
- * return 0 if the action was completed successfully. On error, it
- * should return a nonzero result and set errno.
- * raceproof_create_file() treats two errno values specially:
- *
- * - ENOENT -- dirname(path) does not exist. In this case,
- *             raceproof_create_file() tries creating dirname(path)
- *             (and any parent directories, if necessary) and calls
- *             the function again.
- *
- * - EISDIR -- the file already exists and is a directory. In this
- *             case, raceproof_create_file() removes the directory if
- *             it is empty (and recursively any empty directories that
- *             it contains) and calls the function again.
- *
- * Any other errno causes raceproof_create_file() to fail with the
- * callback's return value and errno.
- *
- * Obviously, this function should be OK with being called again if it
- * fails with ENOENT or EISDIR. In other scenarios it will not be
- * called again.
- */
-typedef int create_file_fn(const char *path, void *cb);
-
-/*
- * Create a file in dirname(path) by calling fn, creating leading
- * directories if necessary. Retry a few times in case we are racing
- * with another process that is trying to clean up the directory that
- * contains path. See the documentation for create_file_fn for more
- * details.
- *
- * Return the value and set the errno that resulted from the most
- * recent call of fn. fn is always called at least once, and will be
- * called more than once if it returns ENOENT or EISDIR.
- */
-int raceproof_create_file(const char *path, create_file_fn fn, void *cb);
-
 int mkdir_in_gitdir(const char *path);
-char *expand_user_path(const char *path, int real_home);
+char *interpolate_path(const char *path, int real_home);
+/* NEEDSWORK: remove this synonym once in-flight topics have migrated */
+#define expand_user_path interpolate_path
 const char *enter_repo(const char *path, int strict);
 static inline int is_absolute_path(const char *path)
 {
@@ -1296,6 +1248,13 @@
 
 /**
  * Return a newly allocated string with the evaluation of
+ * "$XDG_CONFIG_HOME/$subdir/$filename" if $XDG_CONFIG_HOME is non-empty, otherwise
+ * "$HOME/.config/$subdir/$filename". Return NULL upon error.
+ */
+char *xdg_config_home_for(const char *subdir, const char *filename);
+
+/**
+ * Return a newly allocated string with the evaluation of
  * "$XDG_CONFIG_HOME/git/$filename" if $XDG_CONFIG_HOME is non-empty, otherwise
  * "$HOME/.config/git/$filename". Return NULL upon error.
  */
@@ -1310,11 +1269,50 @@
 
 int git_open_cloexec(const char *name, int flags);
 #define git_open(name) git_open_cloexec(name, O_RDONLY)
-int unpack_loose_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz);
-int parse_loose_header(const char *hdr, unsigned long *sizep);
+
+/**
+ * unpack_loose_header() initializes the data stream needed to unpack
+ * a loose object header.
+ *
+ * Returns:
+ *
+ * - ULHR_OK on success
+ * - ULHR_BAD on error
+ * - ULHR_TOO_LONG if the header was too long
+ *
+ * It will only parse up to MAX_HEADER_LEN bytes unless an optional
+ * "hdrbuf" argument is non-NULL. This is intended for use with
+ * OBJECT_INFO_ALLOW_UNKNOWN_TYPE to extract the bad type for (error)
+ * reporting. The full header will be extracted to "hdrbuf" for use
+ * with parse_loose_header(), ULHR_TOO_LONG will still be returned
+ * from this function to indicate that the header was too long.
+ */
+enum unpack_loose_header_result {
+	ULHR_OK,
+	ULHR_BAD,
+	ULHR_TOO_LONG,
+};
+enum unpack_loose_header_result unpack_loose_header(git_zstream *stream,
+						    unsigned char *map,
+						    unsigned long mapsize,
+						    void *buffer,
+						    unsigned long bufsiz,
+						    struct strbuf *hdrbuf);
+
+/**
+ * parse_loose_header() parses the starting "<type> <len>\0" of an
+ * object. If it doesn't follow that format -1 is returned. To check
+ * the validity of the <type> populate the "typep" in the "struct
+ * object_info". It will be OBJ_BAD if the object type is unknown. The
+ * parsed <len> can be retrieved via "oi->sizep", and from there
+ * passed to unpack_loose_rest().
+ */
+struct object_info;
+int parse_loose_header(const char *hdr, struct object_info *oi);
 
 int check_object_signature(struct repository *r, const struct object_id *oid,
-			   void *buf, unsigned long size, const char *type);
+			   void *buf, unsigned long size, const char *type,
+			   struct object_id *real_oidp);
 
 int finalize_object_file(const char *tmpfile, const char *filename);
 
@@ -1659,7 +1657,9 @@
 	int track_flags;
 	int prefix_len_stat_func;
 };
-#define CACHE_DEF_INIT { STRBUF_INIT, 0, 0, 0 }
+#define CACHE_DEF_INIT { \
+	.path = STRBUF_INIT, \
+}
 static inline void cache_def_clear(struct cache_def *cache)
 {
 	strbuf_release(&cache->path);
@@ -1716,13 +1716,6 @@
 const char *get_log_output_encoding(void);
 const char *get_commit_output_encoding(void);
 
-/*
- * This is a hack for test programs like test-dump-untracked-cache to
- * ensure that they do not modify the untracked cache when reading it.
- * Do not use it otherwise!
- */
-extern int ignore_untracked_cache_config;
-
 int committer_ident_sufficiently_given(void);
 int author_ident_sufficiently_given(void);
 
@@ -1735,6 +1728,8 @@
 void maybe_flush_or_die(FILE *, const char *);
 __attribute__((format (printf, 2, 3)))
 void fprintf_or_die(FILE *, const char *fmt, ...);
+void fwrite_or_die(FILE *f, const void *buf, size_t count);
+void fflush_or_die(FILE *f);
 
 #define COPY_READ_ERROR (-2)
 #define COPY_WRITE_ERROR (-3)
diff --git a/cbtree.h b/cbtree.h
index a04a312..dedbb8e 100644
--- a/cbtree.h
+++ b/cbtree.h
@@ -37,11 +37,12 @@
 	CB_BREAK = 1
 };
 
-#define CBTREE_INIT { .root = NULL }
+#define CBTREE_INIT { 0 }
 
 static inline void cb_init(struct cb_tree *t)
 {
-	t->root = NULL;
+	struct cb_tree blank = CBTREE_INIT;
+	memcpy(t, &blank, sizeof(*t));
 }
 
 struct cb_node *cb_lookup(struct cb_tree *, const uint8_t *k, size_t klen);
diff --git a/checkout.c b/checkout.c
index 6586e30..2e39dae 100644
--- a/checkout.c
+++ b/checkout.c
@@ -14,7 +14,7 @@
 	struct object_id *default_dst_oid;
 };
 
-#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0, NULL, NULL, NULL }
+#define TRACKING_NAME_DATA_INIT { 0 }
 
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
diff --git a/ci/install-dependencies.sh b/ci/install-dependencies.sh
index 5772081..1d0e48f 100755
--- a/ci/install-dependencies.sh
+++ b/ci/install-dependencies.sh
@@ -12,7 +12,7 @@
  libemail-valid-perl libio-socket-ssl-perl libnet-smtp-ssl-perl"
 
 case "$jobname" in
-linux-clang|linux-gcc)
+linux-clang|linux-gcc|linux-leaks)
 	sudo apt-add-repository -y "ppa:ubuntu-toolchain-r/test"
 	sudo apt-get -q update
 	sudo apt-get -q -y install language-pack-is libsvn-perl apache2 \
diff --git a/ci/lib.sh b/ci/lib.sh
index 476c3f3..82cb17f 100755
--- a/ci/lib.sh
+++ b/ci/lib.sh
@@ -183,7 +183,7 @@
 export SKIP_DASHED_BUILT_INS=YesPlease
 
 case "$jobname" in
-linux-clang|linux-gcc)
+linux-clang|linux-gcc|linux-leaks)
 	if [ "$jobname" = linux-gcc ]
 	then
 		export CC=gcc-8
@@ -233,4 +233,11 @@
 	;;
 esac
 
+case "$jobname" in
+linux-leaks)
+	export SANITIZE=leak
+	export GIT_TEST_PASSING_SANITIZE_LEAK=true
+	;;
+esac
+
 MAKEFLAGS="$MAKEFLAGS CC=${CC:-cc}"
diff --git a/ci/run-build-and-tests.sh b/ci/run-build-and-tests.sh
index f3aba5d..cc62616 100755
--- a/ci/run-build-and-tests.sh
+++ b/ci/run-build-and-tests.sh
@@ -28,6 +28,7 @@
 	export GIT_TEST_COMMIT_GRAPH=1
 	export GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS=1
 	export GIT_TEST_MULTI_PACK_INDEX=1
+	export GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=1
 	export GIT_TEST_ADD_I_USE_BUILTIN=1
 	export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=master
 	export GIT_TEST_WRITE_REV_INDEX=1
diff --git a/command-list.txt b/command-list.txt
index a289f09..eb9cee8 100644
--- a/command-list.txt
+++ b/command-list.txt
@@ -168,7 +168,7 @@
 git-show-ref                            plumbinginterrogators
 git-sh-i18n                             purehelpers
 git-sh-setup                            purehelpers
-git-sparse-checkout                     mainporcelain           worktree
+git-sparse-checkout                     mainporcelain
 git-stash                               mainporcelain
 git-stage                                                               complete
 git-status                              mainporcelain           info
diff --git a/commit-graph.c b/commit-graph.c
index 3860a0d..2706683 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -713,6 +713,7 @@
 	if (!g)
 		return;
 
+	clear_commit_graph_data_slab(&commit_graph_data_slab);
 	close_commit_graph_one(g->base_graph);
 	free_commit_graph(g);
 }
@@ -723,7 +724,7 @@
 	o->commit_graph = NULL;
 }
 
-static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t *pos)
+static int bsearch_graph(struct commit_graph *g, const struct object_id *oid, uint32_t *pos)
 {
 	return bsearch_hash(oid->hash, g->chunk_oid_fanout,
 			    g->chunk_oid_lookup, g->hash_len, pos);
@@ -864,28 +865,57 @@
 	return 1;
 }
 
-static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
+static int search_commit_pos_in_graph(const struct object_id *id, struct commit_graph *g, uint32_t *pos)
+{
+	struct commit_graph *cur_g = g;
+	uint32_t lex_index;
+
+	while (cur_g && !bsearch_graph(cur_g, id, &lex_index))
+		cur_g = cur_g->base_graph;
+
+	if (cur_g) {
+		*pos = lex_index + cur_g->num_commits_in_base;
+		return 1;
+	}
+
+	return 0;
+}
+
+static int find_commit_pos_in_graph(struct commit *item, struct commit_graph *g, uint32_t *pos)
 {
 	uint32_t graph_pos = commit_graph_position(item);
 	if (graph_pos != COMMIT_NOT_FROM_GRAPH) {
 		*pos = graph_pos;
 		return 1;
 	} else {
-		struct commit_graph *cur_g = g;
-		uint32_t lex_index;
-
-		while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index))
-			cur_g = cur_g->base_graph;
-
-		if (cur_g) {
-			*pos = lex_index + cur_g->num_commits_in_base;
-			return 1;
-		}
-
-		return 0;
+		return search_commit_pos_in_graph(&item->object.oid, g, pos);
 	}
 }
 
+struct commit *lookup_commit_in_graph(struct repository *repo, const struct object_id *id)
+{
+	struct commit *commit;
+	uint32_t pos;
+
+	if (!repo->objects->commit_graph)
+		return NULL;
+	if (!search_commit_pos_in_graph(id, repo->objects->commit_graph, &pos))
+		return NULL;
+	if (!repo_has_object_file(repo, id))
+		return NULL;
+
+	commit = lookup_commit(repo, id);
+	if (!commit)
+		return NULL;
+	if (commit->object.parsed)
+		return commit;
+
+	if (!fill_commit_in_graph(repo, commit, repo->objects->commit_graph, pos))
+		return NULL;
+
+	return commit;
+}
+
 static int parse_commit_in_graph_one(struct repository *r,
 				     struct commit_graph *g,
 				     struct commit *item)
@@ -895,7 +925,7 @@
 	if (item->object.parsed)
 		return 1;
 
-	if (find_commit_in_graph(item, g, &pos))
+	if (find_commit_pos_in_graph(item, g, &pos))
 		return fill_commit_in_graph(r, item, g, pos);
 
 	return 0;
@@ -921,7 +951,7 @@
 	uint32_t pos;
 	if (!prepare_commit_graph(r))
 		return;
-	if (find_commit_in_graph(item, r->objects->commit_graph, &pos))
+	if (find_commit_pos_in_graph(item, r->objects->commit_graph, &pos))
 		fill_commit_graph_info(item, r->objects->commit_graph, pos);
 }
 
@@ -1091,9 +1121,9 @@
 				edge_value += ctx->new_num_commits_in_base;
 			else if (ctx->new_base_graph) {
 				uint32_t pos;
-				if (find_commit_in_graph(parent->item,
-							 ctx->new_base_graph,
-							 &pos))
+				if (find_commit_pos_in_graph(parent->item,
+							     ctx->new_base_graph,
+							     &pos))
 					edge_value = pos;
 			}
 
@@ -1122,9 +1152,9 @@
 				edge_value += ctx->new_num_commits_in_base;
 			else if (ctx->new_base_graph) {
 				uint32_t pos;
-				if (find_commit_in_graph(parent->item,
-							 ctx->new_base_graph,
-							 &pos))
+				if (find_commit_pos_in_graph(parent->item,
+							     ctx->new_base_graph,
+							     &pos))
 					edge_value = pos;
 			}
 
@@ -1235,9 +1265,9 @@
 				edge_value += ctx->new_num_commits_in_base;
 			else if (ctx->new_base_graph) {
 				uint32_t pos;
-				if (find_commit_in_graph(parent->item,
-							 ctx->new_base_graph,
-							 &pos))
+				if (find_commit_pos_in_graph(parent->item,
+							     ctx->new_base_graph,
+							     &pos))
 					edge_value = pos;
 			}
 
@@ -2096,7 +2126,7 @@
 
 	ctx->num_extra_edges = 0;
 	for (i = 0; i < ctx->commits.nr; i++) {
-		display_progress(ctx->progress, i);
+		display_progress(ctx->progress, i + 1);
 
 		if (i && oideq(&ctx->commits.list[i - 1]->object.oid,
 			  &ctx->commits.list[i]->object.oid)) {
diff --git a/commit-graph.h b/commit-graph.h
index 96c24fb..04a94e1 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -41,6 +41,14 @@
 int parse_commit_in_graph(struct repository *r, struct commit *item);
 
 /*
+ * Look up the given commit ID in the commit-graph. This will only return a
+ * commit if the ID exists both in the graph and in the object database such
+ * that we don't return commits whose object has been pruned. Otherwise, this
+ * function returns `NULL`.
+ */
+struct commit *lookup_commit_in_graph(struct repository *repo, const struct object_id *id);
+
+/*
  * It is possible that we loaded commit contents from the commit buffer,
  * but we also want to ensure the commit-graph content is correctly
  * checked and filled. Fill the graph_pos and generation members of
diff --git a/commit.c b/commit.c
index 143f472..551de49 100644
--- a/commit.c
+++ b/commit.c
@@ -25,6 +25,7 @@
 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
 
 int save_commit_buffer = 1;
+int no_graft_file_deprecated_advice;
 
 const char *commit_type = "commit";
 
@@ -190,7 +191,8 @@
 	struct strbuf buf = STRBUF_INIT;
 	if (!fp)
 		return -1;
-	if (advice_graft_file_deprecated)
+	if (!no_graft_file_deprecated_advice &&
+	    advice_enabled(ADVICE_GRAFT_FILE_DEPRECATED))
 		advise(_("Support for <GIT_DIR>/info/grafts is deprecated\n"
 			 "and will be removed in a future Git version.\n"
 			 "\n"
diff --git a/commit.h b/commit.h
index df42eb4..3ea3276 100644
--- a/commit.h
+++ b/commit.h
@@ -41,6 +41,7 @@
 };
 
 extern int save_commit_buffer;
+extern int no_graft_file_deprecated_advice;
 extern const char *commit_type;
 
 /* While we can decorate any object with a name, it's only used for commits.. */
diff --git a/compat/linux/procinfo.c b/compat/linux/procinfo.c
new file mode 100644
index 0000000..bc2f938
--- /dev/null
+++ b/compat/linux/procinfo.c
@@ -0,0 +1,176 @@
+#include "cache.h"
+
+#include "strbuf.h"
+#include "strvec.h"
+#include "trace2.h"
+
+/*
+ * We need more complex parsing in stat_parent_pid() and
+ * parse_proc_stat() below than a dumb fscanf(). That's because while
+ * the statcomm field is surrounded by parentheses, the process itself
+ * is free to insert any arbitrary byte sequence its its name. That
+ * can include newlines, spaces, closing parentheses etc.
+ *
+ * See do_task_stat() in fs/proc/array.c in linux.git, this is in
+ * contrast with the escaped version of the name found in
+ * /proc/%d/status.
+ *
+ * So instead of using fscanf() we'll read N bytes from it, look for
+ * the first "(", and then the last ")", anything in-between is our
+ * process name.
+ *
+ * How much N do we need? On Linux /proc/sys/kernel/pid_max is 2^15 by
+ * default, but it can be raised set to values of up to 2^22. So
+ * that's 7 digits for a PID. We have 2 PIDs in the first four fields
+ * we're interested in, so 2 * 7 = 14.
+ *
+ * We then have 3 spaces between those four values, and we'd like to
+ * get to the space between the 4th and the 5th (the "pgrp" field) to
+ * make sure we read the entire "ppid" field. So that brings us up to
+ * 14 + 3 + 1 = 18. Add the two parentheses around the "comm" value
+ * and it's 20. The "state" value itself is then one character (now at
+ * 21).
+ *
+ * Finally the maximum length of the "comm" name itself is 15
+ * characters, e.g. a setting of "123456789abcdefg" will be truncated
+ * to "123456789abcdef". See PR_SET_NAME in prctl(2). So all in all
+ * we'd need to read 21 + 15 = 36 bytes.
+ *
+ * Let's just read 2^6 (64) instead for good measure. If PID_MAX ever
+ * grows past 2^22 we'll be future-proof. We'll then anchor at the
+ * last ")" we find to locate the parent PID.
+ */
+#define STAT_PARENT_PID_READ_N 64
+
+static int parse_proc_stat(struct strbuf *sb, struct strbuf *name,
+			    int *statppid)
+{
+	const char *comm_lhs = strchr(sb->buf, '(');
+	const char *comm_rhs = strrchr(sb->buf, ')');
+	const char *ppid_lhs, *ppid_rhs;
+	char *p;
+	pid_t ppid;
+
+	if (!comm_lhs || !comm_rhs)
+		goto bad_kernel;
+
+	/*
+	 * We're at the ")", that's followed by " X ", where X is a
+	 * single "state" character. So advance by 4 bytes.
+	 */
+	ppid_lhs = comm_rhs + 4;
+
+	/*
+	 * Read until the space between the "ppid" and "pgrp" fields
+	 * to make sure we're anchored after the untruncated "ppid"
+	 * field..
+	 */
+	ppid_rhs = strchr(ppid_lhs, ' ');
+	if (!ppid_rhs)
+		goto bad_kernel;
+
+	ppid = strtol(ppid_lhs, &p, 10);
+	if (ppid_rhs == p) {
+		const char *comm = comm_lhs + 1;
+		size_t commlen = comm_rhs - comm;
+
+		strbuf_add(name, comm, commlen);
+		*statppid = ppid;
+
+		return 0;
+	}
+
+bad_kernel:
+	/*
+	 * We were able to read our STAT_PARENT_PID_READ_N bytes from
+	 * /proc/%d/stat, but the content is bad. Broken kernel?
+	 * Should not happen, but handle it gracefully.
+	 */
+	return -1;
+}
+
+static int stat_parent_pid(pid_t pid, struct strbuf *name, int *statppid)
+{
+	struct strbuf procfs_path = STRBUF_INIT;
+	struct strbuf sb = STRBUF_INIT;
+	FILE *fp;
+	int ret = -1;
+
+	/* try to use procfs if it's present. */
+	strbuf_addf(&procfs_path, "/proc/%d/stat", pid);
+	fp = fopen(procfs_path.buf, "r");
+	if (!fp)
+		goto cleanup;
+
+	/*
+	 * We could be more strict here and assert that we read at
+	 * least STAT_PARENT_PID_READ_N. My reading of procfs(5) is
+	 * that on any modern kernel (at least since 2.6.0 released in
+	 * 2003) even if all the mandatory numeric fields were zero'd
+	 * out we'd get at least 100 bytes, but let's just check that
+	 * we got anything at all and trust the parse_proc_stat()
+	 * function to handle its "Bad Kernel?" error checking.
+	 */
+	if (!strbuf_fread(&sb, STAT_PARENT_PID_READ_N, fp))
+		goto cleanup;
+	if (parse_proc_stat(&sb, name, statppid) < 0)
+		goto cleanup;
+
+	ret = 0;
+cleanup:
+	if (fp)
+		fclose(fp);
+	strbuf_release(&procfs_path);
+	strbuf_release(&sb);
+
+	return ret;
+}
+
+static void push_ancestry_name(struct strvec *names, pid_t pid)
+{
+	struct strbuf name = STRBUF_INIT;
+	int ppid;
+
+	if (stat_parent_pid(pid, &name, &ppid) < 0)
+		goto cleanup;
+
+	strvec_push(names, name.buf);
+
+	/*
+	 * Both errors and reaching the end of the process chain are
+	 * reported as fields of 0 by proc(5)
+	 */
+	if (ppid)
+		push_ancestry_name(names, ppid);
+cleanup:
+	strbuf_release(&name);
+
+	return;
+}
+
+void trace2_collect_process_info(enum trace2_process_info_reason reason)
+{
+	struct strvec names = STRVEC_INIT;
+
+	if (!trace2_is_enabled())
+		return;
+
+	switch (reason) {
+	case TRACE2_PROCESS_INFO_EXIT:
+		/*
+		 * The Windows version of this calls its
+		 * get_peak_memory_info() here. We may want to insert
+		 * similar process-end statistics here in the future.
+		 */
+		break;
+	case TRACE2_PROCESS_INFO_STARTUP:
+		push_ancestry_name(&names, getppid());
+
+		if (names.nr)
+			trace2_cmd_ancestry(names.v);
+		strvec_clear(&names);
+		break;
+	}
+
+	return;
+}
diff --git a/compat/nedmalloc/nedmalloc.c b/compat/nedmalloc/nedmalloc.c
index 1cc31c3..edb438a 100644
--- a/compat/nedmalloc/nedmalloc.c
+++ b/compat/nedmalloc/nedmalloc.c
@@ -510,7 +510,7 @@
 	assert(idx<=THREADCACHEMAXBINS);
 	if(tck==*binsptr)
 	{
-		fprintf(stderr, "Attempt to free already freed memory block %p - aborting!\n", tck);
+		fprintf(stderr, "Attempt to free already freed memory block %p - aborting!\n", (void *)tck);
 		abort();
 	}
 #ifdef FULLSANITYCHECKS
diff --git a/compat/simple-ipc/ipc-unix-socket.c b/compat/simple-ipc/ipc-unix-socket.c
index 1927e6e..4e28857 100644
--- a/compat/simple-ipc/ipc-unix-socket.c
+++ b/compat/simple-ipc/ipc-unix-socket.c
@@ -168,7 +168,8 @@
 
 int ipc_client_send_command_to_connection(
 	struct ipc_client_connection *connection,
-	const char *message, struct strbuf *answer)
+	const char *message, size_t message_len,
+	struct strbuf *answer)
 {
 	int ret = 0;
 
@@ -176,7 +177,7 @@
 
 	trace2_region_enter("ipc-client", "send-command", NULL);
 
-	if (write_packetized_from_buf_no_flush(message, strlen(message),
+	if (write_packetized_from_buf_no_flush(message, message_len,
 					       connection->fd) < 0 ||
 	    packet_flush_gently(connection->fd) < 0) {
 		ret = error(_("could not send IPC command"));
@@ -197,7 +198,8 @@
 
 int ipc_client_send_command(const char *path,
 			    const struct ipc_client_connect_options *options,
-			    const char *message, struct strbuf *answer)
+			    const char *message, size_t message_len,
+			    struct strbuf *answer)
 {
 	int ret = -1;
 	enum ipc_active_state state;
@@ -208,7 +210,9 @@
 	if (state != IPC_STATE__LISTENING)
 		return ret;
 
-	ret = ipc_client_send_command_to_connection(connection, message, answer);
+	ret = ipc_client_send_command_to_connection(connection,
+						    message, message_len,
+						    answer);
 
 	ipc_client_close_connection(connection);
 
@@ -503,7 +507,7 @@
 	if (ret >= 0) {
 		ret = worker_thread_data->server_data->application_cb(
 			worker_thread_data->server_data->application_data,
-			buf.buf, do_io_reply_callback, &reply_data);
+			buf.buf, buf.len, do_io_reply_callback, &reply_data);
 
 		packet_flush_gently(reply_data.fd);
 	}
diff --git a/compat/simple-ipc/ipc-win32.c b/compat/simple-ipc/ipc-win32.c
index 8dc7bda..20ea7b6 100644
--- a/compat/simple-ipc/ipc-win32.c
+++ b/compat/simple-ipc/ipc-win32.c
@@ -3,6 +3,8 @@
 #include "strbuf.h"
 #include "pkt-line.h"
 #include "thread-utils.h"
+#include "accctrl.h"
+#include "aclapi.h"
 
 #ifndef SUPPORTS_SIMPLE_IPC
 /*
@@ -49,6 +51,9 @@
 	if (GetLastError() == ERROR_FILE_NOT_FOUND)
 		return IPC_STATE__PATH_NOT_FOUND;
 
+	trace2_data_intmax("ipc-debug", NULL, "getstate/waitpipe/gle",
+			   (intmax_t)GetLastError());
+
 	return IPC_STATE__OTHER_ERROR;
 }
 
@@ -109,9 +114,15 @@
 			t_start_ms = (DWORD)(getnanotime() / 1000000);
 
 			if (!WaitNamedPipeW(wpath, timeout_ms)) {
-				if (GetLastError() == ERROR_SEM_TIMEOUT)
+				DWORD gleWait = GetLastError();
+
+				if (gleWait == ERROR_SEM_TIMEOUT)
 					return IPC_STATE__NOT_LISTENING;
 
+				trace2_data_intmax("ipc-debug", NULL,
+						   "connect/waitpipe/gle",
+						   (intmax_t)gleWait);
+
 				return IPC_STATE__OTHER_ERROR;
 			}
 
@@ -133,17 +144,31 @@
 			break; /* try again */
 
 		default:
+			trace2_data_intmax("ipc-debug", NULL,
+					   "connect/createfile/gle",
+					   (intmax_t)gle);
+
 			return IPC_STATE__OTHER_ERROR;
 		}
 	}
 
 	if (!SetNamedPipeHandleState(hPipe, &mode, NULL, NULL)) {
+		gle = GetLastError();
+		trace2_data_intmax("ipc-debug", NULL,
+				   "connect/setpipestate/gle",
+				   (intmax_t)gle);
+
 		CloseHandle(hPipe);
 		return IPC_STATE__OTHER_ERROR;
 	}
 
 	*pfd = _open_osfhandle((intptr_t)hPipe, O_RDWR|O_BINARY);
 	if (*pfd < 0) {
+		gle = GetLastError();
+		trace2_data_intmax("ipc-debug", NULL,
+				   "connect/openosfhandle/gle",
+				   (intmax_t)gle);
+
 		CloseHandle(hPipe);
 		return IPC_STATE__OTHER_ERROR;
 	}
@@ -208,7 +233,8 @@
 
 int ipc_client_send_command_to_connection(
 	struct ipc_client_connection *connection,
-	const char *message, struct strbuf *answer)
+	const char *message, size_t message_len,
+	struct strbuf *answer)
 {
 	int ret = 0;
 
@@ -216,7 +242,7 @@
 
 	trace2_region_enter("ipc-client", "send-command", NULL);
 
-	if (write_packetized_from_buf_no_flush(message, strlen(message),
+	if (write_packetized_from_buf_no_flush(message, message_len,
 					       connection->fd) < 0 ||
 	    packet_flush_gently(connection->fd) < 0) {
 		ret = error(_("could not send IPC command"));
@@ -239,7 +265,8 @@
 
 int ipc_client_send_command(const char *path,
 			    const struct ipc_client_connect_options *options,
-			    const char *message, struct strbuf *response)
+			    const char *message, size_t message_len,
+			    struct strbuf *response)
 {
 	int ret = -1;
 	enum ipc_active_state state;
@@ -250,7 +277,9 @@
 	if (state != IPC_STATE__LISTENING)
 		return ret;
 
-	ret = ipc_client_send_command_to_connection(connection, message, response);
+	ret = ipc_client_send_command_to_connection(connection,
+						    message, message_len,
+						    response);
 
 	ipc_client_close_connection(connection);
 
@@ -458,7 +487,7 @@
 	if (ret >= 0) {
 		ret = server_thread_data->server_data->application_cb(
 			server_thread_data->server_data->application_data,
-			buf.buf, do_io_reply_callback, &reply_data);
+			buf.buf, buf.len, do_io_reply_callback, &reply_data);
 
 		packet_flush_gently(reply_data.fd);
 
@@ -565,11 +594,132 @@
 	return NULL;
 }
 
+/*
+ * We need to build a Windows "SECURITY_ATTRIBUTES" object and use it
+ * to apply an ACL when we create the initial instance of the Named
+ * Pipe.  The construction is somewhat involved and consists of
+ * several sequential steps and intermediate objects.
+ *
+ * We use this structure to hold these intermediate pointers so that
+ * we can free them as a group.  (It is unclear from the docs whether
+ * some of these intermediate pointers can be freed before we are
+ * finished using the "lpSA" member.)
+ */
+struct my_sa_data
+{
+	PSID pEveryoneSID;
+	PACL pACL;
+	PSECURITY_DESCRIPTOR pSD;
+	LPSECURITY_ATTRIBUTES lpSA;
+};
+
+static void init_sa(struct my_sa_data *d)
+{
+	memset(d, 0, sizeof(*d));
+}
+
+static void release_sa(struct my_sa_data *d)
+{
+	if (d->pEveryoneSID)
+		FreeSid(d->pEveryoneSID);
+	if (d->pACL)
+		LocalFree(d->pACL);
+	if (d->pSD)
+		LocalFree(d->pSD);
+	if (d->lpSA)
+		LocalFree(d->lpSA);
+
+	memset(d, 0, sizeof(*d));
+}
+
+/*
+ * Create SECURITY_ATTRIBUTES to apply to the initial named pipe.  The
+ * creator of the first server instance gets to set the ACLs on it.
+ *
+ * We allow the well-known group `EVERYONE` to have read+write access
+ * to the named pipe so that clients can send queries to the daemon
+ * and receive the response.
+ *
+ * Normally, this is not necessary since the daemon is usually
+ * automatically started by a foreground command like `git status`,
+ * but in those cases where an elevated Git command started the daemon
+ * (such that the daemon itself runs with elevation), we need to add
+ * the ACL so that non-elevated commands can write to it.
+ *
+ * The following document was helpful:
+ * https://docs.microsoft.com/en-us/windows/win32/secauthz/creating-a-security-descriptor-for-a-new-object-in-c--
+ *
+ * Returns d->lpSA set to a SA or NULL.
+ */
+static LPSECURITY_ATTRIBUTES get_sa(struct my_sa_data *d)
+{
+	SID_IDENTIFIER_AUTHORITY sid_auth_world = SECURITY_WORLD_SID_AUTHORITY;
+#define NR_EA (1)
+	EXPLICIT_ACCESS ea[NR_EA];
+	DWORD dwResult;
+
+	if (!AllocateAndInitializeSid(&sid_auth_world, 1,
+				      SECURITY_WORLD_RID, 0,0,0,0,0,0,0,
+				      &d->pEveryoneSID)) {
+		DWORD gle = GetLastError();
+		trace2_data_intmax("ipc-debug", NULL, "alloc-world-sid/gle",
+				   (intmax_t)gle);
+		goto fail;
+	}
+
+	memset(ea, 0, NR_EA * sizeof(EXPLICIT_ACCESS));
+
+	ea[0].grfAccessPermissions = GENERIC_READ | GENERIC_WRITE;
+	ea[0].grfAccessMode = SET_ACCESS;
+	ea[0].grfInheritance = NO_INHERITANCE;
+	ea[0].Trustee.MultipleTrusteeOperation = NO_MULTIPLE_TRUSTEE;
+	ea[0].Trustee.TrusteeForm = TRUSTEE_IS_SID;
+	ea[0].Trustee.TrusteeType = TRUSTEE_IS_WELL_KNOWN_GROUP;
+	ea[0].Trustee.ptstrName = (LPTSTR)d->pEveryoneSID;
+
+	dwResult = SetEntriesInAcl(NR_EA, ea, NULL, &d->pACL);
+	if (dwResult != ERROR_SUCCESS) {
+		DWORD gle = GetLastError();
+		trace2_data_intmax("ipc-debug", NULL, "set-acl-entry/gle",
+				   (intmax_t)gle);
+		trace2_data_intmax("ipc-debug", NULL, "set-acl-entry/dw",
+				   (intmax_t)dwResult);
+		goto fail;
+	}
+
+	d->pSD = (PSECURITY_DESCRIPTOR)LocalAlloc(
+		LPTR, SECURITY_DESCRIPTOR_MIN_LENGTH);
+	if (!InitializeSecurityDescriptor(d->pSD, SECURITY_DESCRIPTOR_REVISION)) {
+		DWORD gle = GetLastError();
+		trace2_data_intmax("ipc-debug", NULL, "init-sd/gle", (intmax_t)gle);
+		goto fail;
+	}
+
+	if (!SetSecurityDescriptorDacl(d->pSD, TRUE, d->pACL, FALSE)) {
+		DWORD gle = GetLastError();
+		trace2_data_intmax("ipc-debug", NULL, "set-sd-dacl/gle", (intmax_t)gle);
+		goto fail;
+	}
+
+	d->lpSA = (LPSECURITY_ATTRIBUTES)LocalAlloc(LPTR, sizeof(SECURITY_ATTRIBUTES));
+	d->lpSA->nLength = sizeof(SECURITY_ATTRIBUTES);
+	d->lpSA->lpSecurityDescriptor = d->pSD;
+	d->lpSA->bInheritHandle = FALSE;
+
+	return d->lpSA;
+
+fail:
+	release_sa(d);
+	return NULL;
+}
+
 static HANDLE create_new_pipe(wchar_t *wpath, int is_first)
 {
 	HANDLE hPipe;
 	DWORD dwOpenMode, dwPipeMode;
-	LPSECURITY_ATTRIBUTES lpsa = NULL;
+	struct my_sa_data my_sa_data;
+
+	init_sa(&my_sa_data);
 
 	dwOpenMode = PIPE_ACCESS_INBOUND | PIPE_ACCESS_OUTBOUND |
 		FILE_FLAG_OVERLAPPED;
@@ -585,20 +735,15 @@
 		 * set the ACL / Security Attributes on the named
 		 * pipe; subsequent instances inherit and cannot
 		 * change them.
-		 *
-		 * TODO Should we allow the application layer to
-		 * specify security attributes, such as `LocalService`
-		 * or `LocalSystem`, when we create the named pipe?
-		 * This question is probably not important when the
-		 * daemon is started by a foreground user process and
-		 * only needs to talk to the current user, but may be
-		 * if the daemon is run via the Control Panel as a
-		 * System Service.
 		 */
+		get_sa(&my_sa_data);
 	}
 
 	hPipe = CreateNamedPipeW(wpath, dwOpenMode, dwPipeMode,
-				 PIPE_UNLIMITED_INSTANCES, 1024, 1024, 0, lpsa);
+				 PIPE_UNLIMITED_INSTANCES, 1024, 1024, 0,
+				 my_sa_data.lpSA);
+
+	release_sa(&my_sa_data);
 
 	return hPipe;
 }
diff --git a/compat/stub/procinfo.c b/compat/stub/procinfo.c
new file mode 100644
index 0000000..12c0a23
--- /dev/null
+++ b/compat/stub/procinfo.c
@@ -0,0 +1,11 @@
+#include "git-compat-util.h"
+
+#include "trace2.h"
+
+/*
+ * Stub. See sample implementations in compat/linux/procinfo.c and
+ * compat/win32/trace2_win32_process_info.c.
+ */
+void trace2_collect_process_info(enum trace2_process_info_reason reason)
+{
+}
diff --git a/compat/terminal.c b/compat/terminal.c
index 43b73dd..5b903e7 100644
--- a/compat/terminal.c
+++ b/compat/terminal.c
@@ -8,8 +8,6 @@
 
 #if defined(HAVE_DEV_TTY) || defined(GIT_WINDOWS_NATIVE)
 
-static void restore_term(void);
-
 static void restore_term_on_signal(int sig)
 {
 	restore_term();
@@ -25,7 +23,7 @@
 static int term_fd = -1;
 static struct termios old_term;
 
-static void restore_term(void)
+void restore_term(void)
 {
 	if (term_fd < 0)
 		return;
@@ -35,15 +33,22 @@
 	term_fd = -1;
 }
 
+int save_term(int full_duplex)
+{
+	if (term_fd < 0)
+		term_fd = open("/dev/tty", O_RDWR);
+
+	return (term_fd < 0) ? -1 : tcgetattr(term_fd, &old_term);
+}
+
 static int disable_bits(tcflag_t bits)
 {
 	struct termios t;
 
-	term_fd = open("/dev/tty", O_RDWR);
-	if (tcgetattr(term_fd, &t) < 0)
+	if (save_term(0) < 0)
 		goto error;
 
-	old_term = t;
+	t = old_term;
 	sigchain_push_common(restore_term_on_signal);
 
 	t.c_lflag &= ~bits;
@@ -75,9 +80,10 @@
 static int use_stty = 1;
 static struct string_list stty_restore = STRING_LIST_INIT_DUP;
 static HANDLE hconin = INVALID_HANDLE_VALUE;
-static DWORD cmode;
+static HANDLE hconout = INVALID_HANDLE_VALUE;
+static DWORD cmode_in, cmode_out;
 
-static void restore_term(void)
+void restore_term(void)
 {
 	if (use_stty) {
 		int i;
@@ -97,9 +103,42 @@
 	if (hconin == INVALID_HANDLE_VALUE)
 		return;
 
-	SetConsoleMode(hconin, cmode);
+	SetConsoleMode(hconin, cmode_in);
+	CloseHandle(hconin);
+	if (cmode_out) {
+		assert(hconout != INVALID_HANDLE_VALUE);
+		SetConsoleMode(hconout, cmode_out);
+		CloseHandle(hconout);
+	}
+
+	hconin = hconout = INVALID_HANDLE_VALUE;
+}
+
+int save_term(int full_duplex)
+{
+	hconin = CreateFileA("CONIN$", GENERIC_READ | GENERIC_WRITE,
+	    FILE_SHARE_READ, NULL, OPEN_EXISTING,
+	    FILE_ATTRIBUTE_NORMAL, NULL);
+	if (hconin == INVALID_HANDLE_VALUE)
+		return -1;
+
+	if (full_duplex) {
+		hconout = CreateFileA("CONOUT$", GENERIC_READ | GENERIC_WRITE,
+			FILE_SHARE_WRITE, NULL, OPEN_EXISTING,
+			FILE_ATTRIBUTE_NORMAL, NULL);
+		if (hconout == INVALID_HANDLE_VALUE)
+			goto error;
+
+		GetConsoleMode(hconout, &cmode_out);
+	}
+
+	GetConsoleMode(hconin, &cmode_in);
+	use_stty = 0;
+	return 0;
+error:
 	CloseHandle(hconin);
 	hconin = INVALID_HANDLE_VALUE;
+	return -1;
 }
 
 static int disable_bits(DWORD bits)
@@ -135,15 +174,11 @@
 		use_stty = 0;
 	}
 
-	hconin = CreateFile("CONIN$", GENERIC_READ | GENERIC_WRITE,
-	    FILE_SHARE_READ, NULL, OPEN_EXISTING,
-	    FILE_ATTRIBUTE_NORMAL, NULL);
-	if (hconin == INVALID_HANDLE_VALUE)
+	if (save_term(0) < 0)
 		return -1;
 
-	GetConsoleMode(hconin, &cmode);
 	sigchain_push_common(restore_term_on_signal);
-	if (!SetConsoleMode(hconin, cmode & ~bits)) {
+	if (!SetConsoleMode(hconin, cmode_in & ~bits)) {
 		CloseHandle(hconin);
 		hconin = INVALID_HANDLE_VALUE;
 		return -1;
@@ -361,6 +396,16 @@
 
 #else
 
+int save_term(int full_duplex)
+{
+	/* full_duplex == 1, but no support available */
+	return -full_duplex;
+}
+
+void restore_term(void)
+{
+}
+
 char *git_terminal_prompt(const char *prompt, int echo)
 {
 	return getpass(prompt);
diff --git a/compat/terminal.h b/compat/terminal.h
index a9d52b8..e1770c5 100644
--- a/compat/terminal.h
+++ b/compat/terminal.h
@@ -1,6 +1,9 @@
 #ifndef COMPAT_TERMINAL_H
 #define COMPAT_TERMINAL_H
 
+int save_term(int full_duplex);
+void restore_term(void);
+
 char *git_terminal_prompt(const char *prompt, int echo);
 
 /* Read a single keystroke, without echoing it to the terminal */
diff --git a/compat/vcbuild/README b/compat/vcbuild/README
index 51fb083..29ec1d0 100644
--- a/compat/vcbuild/README
+++ b/compat/vcbuild/README
@@ -92,7 +92,7 @@
    the git operations.
 
 3. Inside Git's directory run the command:
-       make command-list.h config-list.h
+       make generated-hdrs
    to generate the header file needed to compile git.
 
 4. Then either build Git with the GNU Make Makefile in the Git projects
diff --git a/compat/win32/lazyload.h b/compat/win32/lazyload.h
index 9e631c8..2b36371 100644
--- a/compat/win32/lazyload.h
+++ b/compat/win32/lazyload.h
@@ -15,10 +15,12 @@
  *                        source, target);
  */
 
+typedef void (*FARVOIDPROC)(void);
+
 struct proc_addr {
 	const char *const dll;
 	const char *const function;
-	FARPROC pfunction;
+	FARVOIDPROC pfunction;
 	unsigned initialized : 1;
 };
 
@@ -26,7 +28,8 @@
 #define DECLARE_PROC_ADDR(dll, rettype, function, ...) \
 	static struct proc_addr proc_addr_##function = \
 	{ #dll, #function, NULL, 0 }; \
-	static rettype (WINAPI *function)(__VA_ARGS__)
+	typedef rettype (WINAPI *proc_type_##function)(__VA_ARGS__); \
+	static proc_type_##function function
 
 /*
  * Loads a function from a DLL (once-only).
@@ -35,9 +38,9 @@
  * This function is not thread-safe.
  */
 #define INIT_PROC_ADDR(function) \
-	(function = get_proc_addr(&proc_addr_##function))
+	(function = (proc_type_##function)get_proc_addr(&proc_addr_##function))
 
-static inline void *get_proc_addr(struct proc_addr *proc)
+static inline FARVOIDPROC get_proc_addr(struct proc_addr *proc)
 {
 	/* only do this once */
 	if (!proc->initialized) {
@@ -46,7 +49,8 @@
 		hnd = LoadLibraryExA(proc->dll, NULL,
 				     LOAD_LIBRARY_SEARCH_SYSTEM32);
 		if (hnd)
-			proc->pfunction = GetProcAddress(hnd, proc->function);
+			proc->pfunction = (FARVOIDPROC)GetProcAddress(hnd,
+							proc->function);
 	}
 	/* set ENOSYS if DLL or function was not found */
 	if (!proc->pfunction)
diff --git a/config.c b/config.c
index 7a6ff18..c5873f3 100644
--- a/config.c
+++ b/config.c
@@ -136,7 +136,7 @@
 	if (!path)
 		return config_error_nonbool("include.path");
 
-	expanded = expand_user_path(path, 0);
+	expanded = interpolate_path(path, 0);
 	if (!expanded)
 		return error(_("could not expand include path '%s'"), path);
 	path = expanded;
@@ -148,8 +148,10 @@
 	if (!is_absolute_path(path)) {
 		char *slash;
 
-		if (!cf || !cf->path)
-			return error(_("relative config includes must come from files"));
+		if (!cf || !cf->path) {
+			ret = error(_("relative config includes must come from files"));
+			goto cleanup;
+		}
 
 		slash = find_last_dir_sep(cf->path);
 		if (slash)
@@ -167,6 +169,7 @@
 		ret = git_config_from_file(git_config_include, path, inc);
 		inc->depth--;
 	}
+cleanup:
 	strbuf_release(&buf);
 	free(expanded);
 	return ret;
@@ -184,7 +187,7 @@
 	char *expanded;
 	int prefix = 0;
 
-	expanded = expand_user_path(pat->buf, 1);
+	expanded = interpolate_path(pat->buf, 1);
 	if (expanded) {
 		strbuf_reset(pat);
 		strbuf_addstr(pat, expanded);
@@ -425,7 +428,7 @@
  * baselen - pointer to size_t which will hold the length of the
  *           section + subsection part, can be NULL
  */
-static int git_config_parse_key_1(const char *key, char **store_key, size_t *baselen_, int quiet)
+int git_config_parse_key(const char *key, char **store_key, size_t *baselen_)
 {
 	size_t i, baselen;
 	int dot;
@@ -437,14 +440,12 @@
 	 */
 
 	if (last_dot == NULL || last_dot == key) {
-		if (!quiet)
-			error(_("key does not contain a section: %s"), key);
+		error(_("key does not contain a section: %s"), key);
 		return -CONFIG_NO_SECTION_OR_NAME;
 	}
 
 	if (!last_dot[1]) {
-		if (!quiet)
-			error(_("key does not contain variable name: %s"), key);
+		error(_("key does not contain variable name: %s"), key);
 		return -CONFIG_NO_SECTION_OR_NAME;
 	}
 
@@ -455,8 +456,7 @@
 	/*
 	 * Validate the key and while at it, lower case it for matching.
 	 */
-	if (store_key)
-		*store_key = xmallocz(strlen(key));
+	*store_key = xmallocz(strlen(key));
 
 	dot = 0;
 	for (i = 0; key[i]; i++) {
@@ -467,39 +467,24 @@
 		if (!dot || i > baselen) {
 			if (!iskeychar(c) ||
 			    (i == baselen + 1 && !isalpha(c))) {
-				if (!quiet)
-					error(_("invalid key: %s"), key);
+				error(_("invalid key: %s"), key);
 				goto out_free_ret_1;
 			}
 			c = tolower(c);
 		} else if (c == '\n') {
-			if (!quiet)
-				error(_("invalid key (newline): %s"), key);
+			error(_("invalid key (newline): %s"), key);
 			goto out_free_ret_1;
 		}
-		if (store_key)
-			(*store_key)[i] = c;
+		(*store_key)[i] = c;
 	}
 
 	return 0;
 
 out_free_ret_1:
-	if (store_key) {
-		FREE_AND_NULL(*store_key);
-	}
+	FREE_AND_NULL(*store_key);
 	return -CONFIG_INVALID_KEY;
 }
 
-int git_config_parse_key(const char *key, char **store_key, size_t *baselen)
-{
-	return git_config_parse_key_1(key, store_key, baselen, 0);
-}
-
-int git_config_key_is_valid(const char *key)
-{
-	return !git_config_parse_key_1(key, NULL, NULL, 1);
-}
-
 static int config_parse_pair(const char *key, const char *value,
 			  config_fn_t fn, void *data)
 {
@@ -1269,7 +1254,7 @@
 {
 	if (!value)
 		return config_error_nonbool(var);
-	*dest = expand_user_path(value, 0);
+	*dest = interpolate_path(value, 0);
 	if (!*dest)
 		die(_("failed to expand user dir in: '%s'"), value);
 	return 0;
@@ -1793,6 +1778,7 @@
 
 int git_config_from_blob_oid(config_fn_t fn,
 			      const char *name,
+			      struct repository *repo,
 			      const struct object_id *oid,
 			      void *data)
 {
@@ -1801,7 +1787,7 @@
 	unsigned long size;
 	int ret;
 
-	buf = read_object_file(oid, &type, &size);
+	buf = repo_read_object_file(repo, oid, &type, &size);
 	if (!buf)
 		return error(_("unable to load config blob object '%s'"), name);
 	if (type != OBJ_BLOB) {
@@ -1817,14 +1803,15 @@
 }
 
 static int git_config_from_blob_ref(config_fn_t fn,
+				    struct repository *repo,
 				    const char *name,
 				    void *data)
 {
 	struct object_id oid;
 
-	if (get_oid(name, &oid) < 0)
+	if (repo_get_oid(repo, name, &oid) < 0)
 		return error(_("unable to resolve config blob '%s'"), name);
-	return git_config_from_blob_oid(fn, name, &oid, data);
+	return git_config_from_blob_oid(fn, name, repo, &oid, data);
 }
 
 char *git_system_config(void)
@@ -1842,7 +1829,7 @@
 	char *xdg_config = NULL;
 
 	if (!user_config) {
-		user_config = expand_user_path("~/.gitconfig", 0);
+		user_config = interpolate_path("~/.gitconfig", 0);
 		xdg_config = xdg_config_home("config");
 	}
 
@@ -1955,12 +1942,16 @@
 	 * If we have a specific filename, use it. Otherwise, follow the
 	 * regular lookup sequence.
 	 */
-	if (config_source && config_source->use_stdin)
+	if (config_source && config_source->use_stdin) {
 		return git_config_from_stdin(fn, data);
-	else if (config_source && config_source->file)
+	} else if (config_source && config_source->file) {
 		return git_config_from_file(fn, config_source->file, data);
-	else if (config_source && config_source->blob)
-		return git_config_from_blob_ref(fn, config_source->blob, data);
+	} else if (config_source && config_source->blob) {
+		struct repository *repo = config_source->repo ?
+			config_source->repo : the_repository;
+		return git_config_from_blob_ref(fn, repo, config_source->blob,
+						data);
+	}
 
 	return do_git_config_sequence(opts, fn, data);
 }
diff --git a/config.h b/config.h
index a2200f3..f119de0 100644
--- a/config.h
+++ b/config.h
@@ -49,6 +49,8 @@
 struct git_config_source {
 	unsigned int use_stdin:1;
 	const char *file;
+	/* The repository if blob is not NULL; leave blank for the_repository */
+	struct repository *repo;
 	const char *blob;
 	enum config_scope scope;
 };
@@ -136,6 +138,7 @@
 			const char *buf, size_t len,
 			void *data, const struct config_options *opts);
 int git_config_from_blob_oid(config_fn_t fn, const char *name,
+			     struct repository *repo,
 			     const struct object_id *oid, void *data);
 void git_config_push_parameter(const char *text);
 void git_config_push_env(const char *spec);
@@ -256,7 +259,6 @@
 void git_config_set(const char *, const char *);
 
 int git_config_parse_key(const char *, char **, size_t *);
-int git_config_key_is_valid(const char *key);
 
 /*
  * The following macros specify flag bits that alter the behavior
@@ -606,7 +608,6 @@
 int git_config_get_pathname(const char *key, const char **dest);
 
 int git_config_get_index_threads(int *dest);
-int git_config_get_untracked_cache(void);
 int git_config_get_split_index(void);
 int git_config_get_max_percent_split_change(void);
 int git_config_get_fsmonitor(void);
diff --git a/config.mak.dev b/config.mak.dev
index 022fb58..7673fed 100644
--- a/config.mak.dev
+++ b/config.mak.dev
@@ -1,13 +1,24 @@
+ifndef COMPILER_FEATURES
+COMPILER_FEATURES := $(shell ./detect-compiler $(CC))
+endif
+
 ifeq ($(filter no-error,$(DEVOPTS)),)
 DEVELOPER_CFLAGS += -Werror
 SPARSE_FLAGS += -Wsparse-error
 endif
-ifneq ($(filter pedantic,$(DEVOPTS)),)
-DEVELOPER_CFLAGS += -pedantic
-# don't warn for each N_ use
-DEVELOPER_CFLAGS += -DUSE_PARENS_AROUND_GETTEXT_N=0
-endif
+
 DEVELOPER_CFLAGS += -Wall
+ifeq ($(filter no-pedantic,$(DEVOPTS)),)
+DEVELOPER_CFLAGS += -pedantic
+ifneq (($or $(filter gcc5,$(COMPILER_FEATURES)),$(filter clang4,$(COMPILER_FEATURES))),)
+DEVELOPER_CFLAGS += -Wpedantic
+ifneq ($(filter gcc10,$(COMPILER_FEATURES)),)
+ifeq ($(uname_S),MINGW)
+DEVELOPER_CFLAGS += -Wno-pedantic-ms-format
+endif
+endif
+endif
+endif
 DEVELOPER_CFLAGS += -Wdeclaration-after-statement
 DEVELOPER_CFLAGS += -Wformat-security
 DEVELOPER_CFLAGS += -Wold-style-definition
@@ -18,10 +29,6 @@
 DEVELOPER_CFLAGS += -Wvla
 DEVELOPER_CFLAGS += -fno-common
 
-ifndef COMPILER_FEATURES
-COMPILER_FEATURES := $(shell ./detect-compiler $(CC))
-endif
-
 ifneq ($(filter clang4,$(COMPILER_FEATURES)),)
 DEVELOPER_CFLAGS += -Wtautological-constant-out-of-range-compare
 endif
diff --git a/config.mak.uname b/config.mak.uname
index 69413fb..3236a49 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -11,6 +11,10 @@
 uname_P := $(shell sh -c 'uname -p 2>/dev/null || echo not')
 uname_V := $(shell sh -c 'uname -v 2>/dev/null || echo not')
 
+ifneq ($(findstring MINGW,$(uname_S)),)
+	uname_S := MINGW
+endif
+
 ifdef MSVC
 	# avoid the MingW and Cygwin configuration sections
 	uname_S := Windows
@@ -58,6 +62,8 @@
 	FREAD_READS_DIRECTORIES = UnfortunatelyYes
 	BASIC_CFLAGS += -DHAVE_SYSINFO
 	PROCFS_EXECUTABLE_PATH = /proc/self/exe
+	HAVE_PLATFORM_PROCINFO = YesPlease
+	COMPAT_OBJS += compat/linux/procinfo.o
 endif
 ifeq ($(uname_S),GNU/kFreeBSD)
 	HAVE_ALLOCA_H = YesPlease
@@ -586,7 +592,7 @@
 	SANE_TOOL_PATH = /usr/coreutils/bin:/usr/local/bin
 	SHELL_PATH = /usr/coreutils/bin/bash
 endif
-ifneq (,$(findstring MINGW,$(uname_S)))
+ifeq ($(uname_S),MINGW)
 	pathsep = ;
 	HAVE_ALLOCA_H = YesPlease
 	NO_PREAD = YesPlease
@@ -617,6 +623,7 @@
 	ETAGS_TARGET = ETAGS
 	NO_POSIX_GOODIES = UnfortunatelyYes
 	DEFAULT_HELP_FORMAT = html
+	HAVE_PLATFORM_PROCINFO = YesPlease
 	BASIC_LDFLAGS += -municode
 	COMPAT_CFLAGS += -DNOGDI -Icompat -Icompat/win32
 	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
@@ -732,9 +739,9 @@
 	 echo '</Project>') >git-remote-http/LinkOrCopyRemoteHttp.targets
 	git add -f git/LinkOrCopyBuiltins.targets git-remote-http/LinkOrCopyRemoteHttp.targets
 
-	# Add command-list.h and config-list.h
-	$(MAKE) MSVC=1 SKIP_VCPKG=1 prefix=/mingw64 config-list.h command-list.h
-	git add -f config-list.h command-list.h
+	# Add generated headers
+	$(MAKE) MSVC=1 SKIP_VCPKG=1 prefix=/mingw64 $(GENERATED_H)
+	git add -f $(GENERATED_H)
 
 	# Add scripts
 	rm -f perl/perl.mak
diff --git a/connected.c b/connected.c
index b18299f..cf68e37 100644
--- a/connected.c
+++ b/connected.c
@@ -24,7 +24,7 @@
 	struct child_process rev_list = CHILD_PROCESS_INIT;
 	FILE *rev_list_in;
 	struct check_connected_options defaults = CHECK_CONNECTED_INIT;
-	struct object_id oid;
+	const struct object_id *oid;
 	int err = 0;
 	struct packed_git *new_pack = NULL;
 	struct transport *transport;
@@ -34,7 +34,8 @@
 		opt = &defaults;
 	transport = opt->transport;
 
-	if (fn(cb_data, &oid)) {
+	oid = fn(cb_data);
+	if (!oid) {
 		if (opt->err_fd)
 			close(opt->err_fd);
 		return err;
@@ -73,7 +74,7 @@
 			for (p = get_all_packs(the_repository); p; p = p->next) {
 				if (!p->pack_promisor)
 					continue;
-				if (find_pack_entry_one(oid.hash, p))
+				if (find_pack_entry_one(oid->hash, p))
 					goto promisor_pack_found;
 			}
 			/*
@@ -83,7 +84,7 @@
 			goto no_promisor_pack_found;
 promisor_pack_found:
 			;
-		} while (!fn(cb_data, &oid));
+		} while ((oid = fn(cb_data)) != NULL);
 		return 0;
 	}
 
@@ -106,6 +107,7 @@
 	if (opt->progress)
 		strvec_pushf(&rev_list.args, "--progress=%s",
 			     _("Checking connectivity"));
+	strvec_push(&rev_list.args, "--unsorted-input");
 
 	rev_list.git_cmd = 1;
 	rev_list.env = opt->env;
@@ -132,12 +134,12 @@
 		 * are sure the ref is good and not sending it to
 		 * rev-list for verification.
 		 */
-		if (new_pack && find_pack_entry_one(oid.hash, new_pack))
+		if (new_pack && find_pack_entry_one(oid->hash, new_pack))
 			continue;
 
-		if (fprintf(rev_list_in, "%s\n", oid_to_hex(&oid)) < 0)
+		if (fprintf(rev_list_in, "%s\n", oid_to_hex(oid)) < 0)
 			break;
-	} while (!fn(cb_data, &oid));
+	} while ((oid = fn(cb_data)) != NULL);
 
 	if (ferror(rev_list_in) || fflush(rev_list_in)) {
 		if (errno != EPIPE && errno != EINVAL)
diff --git a/connected.h b/connected.h
index 8d5a6b3..6e59c92 100644
--- a/connected.h
+++ b/connected.h
@@ -9,7 +9,7 @@
  * When called after returning the name for the last object, return -1
  * to signal EOF, otherwise return 0.
  */
-typedef int (*oid_iterate_fn)(void *, struct object_id *oid);
+typedef const struct object_id *(*oid_iterate_fn)(void *);
 
 /*
  * Named-arguments struct for check_connected. All arguments are
diff --git a/contrib/buildsystems/CMakeLists.txt b/contrib/buildsystems/CMakeLists.txt
index 171b412..fd1399c 100644
--- a/contrib/buildsystems/CMakeLists.txt
+++ b/contrib/buildsystems/CMakeLists.txt
@@ -624,6 +624,13 @@
 			OUTPUT_FILE ${CMAKE_BINARY_DIR}/config-list.h)
 endif()
 
+if(NOT EXISTS ${CMAKE_BINARY_DIR}/hook-list.h)
+	message("Generating hook-list.h")
+	execute_process(COMMAND ${SH_EXE} ${CMAKE_SOURCE_DIR}/generate-hooklist.sh
+			WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+			OUTPUT_FILE ${CMAKE_BINARY_DIR}/hook-list.h)
+endif()
+
 include_directories(${CMAKE_BINARY_DIR})
 
 #build
diff --git a/contrib/coccinelle/xopen.cocci b/contrib/coccinelle/xopen.cocci
index 814d7b8..b71db67 100644
--- a/contrib/coccinelle/xopen.cocci
+++ b/contrib/coccinelle/xopen.cocci
@@ -2,15 +2,18 @@
 identifier fd;
 identifier die_fn =~ "^(die|die_errno)$";
 @@
-(
-  fd =
-- open
-+ xopen
-  (...);
-|
   int fd =
 - open
 + xopen
   (...);
-)
+- if ( \( fd < 0 \| fd == -1 \) ) { die_fn(...); }
+
+@@
+expression fd;
+identifier die_fn =~ "^(die|die_errno)$";
+@@
+  fd =
+- open
++ xopen
+  (...);
 - if ( \( fd < 0 \| fd == -1 \) ) { die_fn(...); }
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 0a20fa5..7c3a753 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -2503,7 +2503,14 @@
 __git_compute_config_vars ()
 {
 	test -n "$__git_config_vars" ||
-	__git_config_vars="$(git help --config-for-completion | sort -u)"
+	__git_config_vars="$(git help --config-for-completion)"
+}
+
+__git_config_sections=
+__git_compute_config_sections ()
+{
+	test -n "$__git_config_sections" ||
+	__git_config_sections="$(git help --config-sections-for-completion)"
 }
 
 # Completes possible values of various configuration variables.
@@ -2543,7 +2550,7 @@
 		return
 		;;
 	branch.*.rebase)
-		__gitcomp "false true merges preserve interactive" "" "$cur_"
+		__gitcomp "false true merges interactive" "" "$cur_"
 		return
 		;;
 	remote.pushdefault)
@@ -2717,16 +2724,8 @@
 		__gitcomp "$__git_config_vars" "" "$cur_" "$sfx"
 		;;
 	*)
-		__git_compute_config_vars
-		__gitcomp "$(echo "$__git_config_vars" |
-				awk -F . '{
-					sections[$1] = 1
-				}
-				END {
-					for (s in sections)
-						print s "."
-				}
-				')" "" "$cur_"
+		__git_compute_config_sections
+		__gitcomp "$__git_config_sections" "" "$cur_" "."
 		;;
 	esac
 }
diff --git a/contrib/credential/gnome-keyring/git-credential-gnome-keyring.c b/contrib/credential/gnome-keyring/git-credential-gnome-keyring.c
index d389bfa..5927e27 100644
--- a/contrib/credential/gnome-keyring/git-credential-gnome-keyring.c
+++ b/contrib/credential/gnome-keyring/git-credential-gnome-keyring.c
@@ -138,7 +138,7 @@
 	char *password;
 };
 
-#define CREDENTIAL_INIT { NULL, NULL, 0, NULL, NULL, NULL }
+#define CREDENTIAL_INIT { 0 }
 
 typedef int (*credential_op_cb)(struct credential *);
 
diff --git a/contrib/credential/libsecret/git-credential-libsecret.c b/contrib/credential/libsecret/git-credential-libsecret.c
index e6598b6..2c5d76d 100644
--- a/contrib/credential/libsecret/git-credential-libsecret.c
+++ b/contrib/credential/libsecret/git-credential-libsecret.c
@@ -41,7 +41,7 @@
 	char *password;
 };
 
-#define CREDENTIAL_INIT { NULL, NULL, 0, NULL, NULL, NULL }
+#define CREDENTIAL_INIT { 0 }
 
 typedef int (*credential_op_cb)(struct credential *);
 
diff --git a/contrib/rerere-train.sh b/contrib/rerere-train.sh
index eeee45d..75125d6 100755
--- a/contrib/rerere-train.sh
+++ b/contrib/rerere-train.sh
@@ -91,7 +91,7 @@
 		git checkout -q $commit -- .
 		git rerere
 	fi
-	git reset -q --hard
+	git reset -q --hard  # Might nuke untracked files...
 done
 
 if test -z "$branch"
diff --git a/credential.c b/credential.c
index 000ac7a..e7240f3 100644
--- a/credential.c
+++ b/credential.c
@@ -105,7 +105,7 @@
 static void credential_apply_config(struct credential *c)
 {
 	char *normalized_url;
-	struct urlmatch_config config = { STRING_LIST_INIT_DUP };
+	struct urlmatch_config config = URLMATCH_CONFIG_INIT;
 	struct strbuf url = STRBUF_INIT;
 
 	if (!c->host)
diff --git a/daemon.c b/daemon.c
index 5c4cbad..b1fcbe0 100644
--- a/daemon.c
+++ b/daemon.c
@@ -63,6 +63,12 @@
 	unsigned int hostname_lookup_done:1;
 	unsigned int saw_extended_args:1;
 };
+#define HOSTINFO_INIT { \
+	.hostname = STRBUF_INIT, \
+	.canon_hostname = STRBUF_INIT, \
+	.ip_address = STRBUF_INIT, \
+	.tcp_port = STRBUF_INIT, \
+}
 
 static void lookup_hostname(struct hostinfo *hi);
 
@@ -727,15 +733,6 @@
 	}
 }
 
-static void hostinfo_init(struct hostinfo *hi)
-{
-	memset(hi, 0, sizeof(*hi));
-	strbuf_init(&hi->hostname, 0);
-	strbuf_init(&hi->canon_hostname, 0);
-	strbuf_init(&hi->ip_address, 0);
-	strbuf_init(&hi->tcp_port, 0);
-}
-
 static void hostinfo_clear(struct hostinfo *hi)
 {
 	strbuf_release(&hi->hostname);
@@ -760,17 +757,15 @@
 	char *line = packet_buffer;
 	int pktlen, len, i;
 	char *addr = getenv("REMOTE_ADDR"), *port = getenv("REMOTE_PORT");
-	struct hostinfo hi;
+	struct hostinfo hi = HOSTINFO_INIT;
 	struct strvec env = STRVEC_INIT;
 
-	hostinfo_init(&hi);
-
 	if (addr)
 		loginfo("Connection from %s:%s", addr, port);
 
 	set_keep_alive(0);
 	alarm(init_timeout ? init_timeout : timeout);
-	pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
+	pktlen = packet_read(0, packet_buffer, sizeof(packet_buffer), 0);
 	alarm(0);
 
 	len = strlen(line);
diff --git a/diff.c b/diff.c
index a8113f1..861282d 100644
--- a/diff.c
+++ b/diff.c
@@ -26,6 +26,7 @@
 #include "parse-options.h"
 #include "help.h"
 #include "promisor-remote.h"
+#include "dir.h"
 
 #ifdef NO_FAST_WORKING_DIRECTORY
 #define FAST_WORKING_DIRECTORY 0
@@ -774,13 +775,13 @@
 	int indent_width; /* The visual width of the indentation */
 	enum diff_symbol s;
 };
-#define EMITTED_DIFF_SYMBOL_INIT {NULL}
+#define EMITTED_DIFF_SYMBOL_INIT { 0 }
 
 struct emitted_diff_symbols {
 	struct emitted_diff_symbol *buf;
 	int nr, alloc;
 };
-#define EMITTED_DIFF_SYMBOLS_INIT {NULL, 0, 0}
+#define EMITTED_DIFF_SYMBOLS_INIT { 0 }
 
 static void append_emitted_diff_symbol(struct diff_options *o,
 				       struct emitted_diff_symbol *e)
@@ -3907,6 +3908,13 @@
 	if (!want_file && would_convert_to_git(istate, name))
 		return 0;
 
+	/*
+	 * If this path does not match our sparse-checkout definition,
+	 * then the file will not be in the working directory.
+	 */
+	if (!path_in_sparse_checkout(name, istate))
+		return 0;
+
 	len = strlen(name);
 	pos = index_name_pos(istate, name, len);
 	if (pos < 0)
diff --git a/diffcore-rename.c b/diffcore-rename.c
index c95857b..bebd4ed 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -317,10 +317,11 @@
 }
 
 static void insert_file_table(struct repository *r,
+			      struct mem_pool *pool,
 			      struct hashmap *table, int index,
 			      struct diff_filespec *filespec)
 {
-	struct file_similarity *entry = xmalloc(sizeof(*entry));
+	struct file_similarity *entry = mem_pool_alloc(pool, sizeof(*entry));
 
 	entry->index = index;
 	entry->filespec = filespec;
@@ -336,7 +337,8 @@
  * and then during the second round we try to match
  * cache-dirty entries as well.
  */
-static int find_exact_renames(struct diff_options *options)
+static int find_exact_renames(struct diff_options *options,
+			      struct mem_pool *pool)
 {
 	int i, renames = 0;
 	struct hashmap file_table;
@@ -346,7 +348,7 @@
 	 */
 	hashmap_init(&file_table, NULL, NULL, rename_src_nr);
 	for (i = rename_src_nr-1; i >= 0; i--)
-		insert_file_table(options->repo,
+		insert_file_table(options->repo, pool,
 				  &file_table, i,
 				  rename_src[i].p->one);
 
@@ -354,8 +356,8 @@
 	for (i = 0; i < rename_dst_nr; i++)
 		renames += find_identical_files(&file_table, i, options);
 
-	/* Free the hash data structure and entries */
-	hashmap_clear_and_free(&file_table, struct file_similarity, entry);
+	/* Free the hash data structure (entries will be freed with the pool) */
+	hashmap_clear(&file_table);
 
 	return renames;
 }
@@ -1330,7 +1332,47 @@
 	rename_src_nr = new_num_src;
 }
 
+static void free_filespec_data(struct diff_filespec *spec)
+{
+	if (!--spec->count)
+		diff_free_filespec_data(spec);
+}
+
+static void pool_free_filespec(struct mem_pool *pool,
+			       struct diff_filespec *spec)
+{
+	if (!pool) {
+		free_filespec(spec);
+		return;
+	}
+
+	/*
+	 * Similar to free_filespec(), but only frees the data.  The spec
+	 * itself was allocated in the pool and should not be individually
+	 * freed.
+	 */
+	free_filespec_data(spec);
+}
+
+void pool_diff_free_filepair(struct mem_pool *pool,
+			     struct diff_filepair *p)
+{
+	if (!pool) {
+		diff_free_filepair(p);
+		return;
+	}
+
+	/*
+	 * Similar to diff_free_filepair() but only frees the data from the
+	 * filespecs; not the filespecs or the filepair which were
+	 * allocated from the pool.
+	 */
+	free_filespec_data(p->one);
+	free_filespec_data(p->two);
+}
+
 void diffcore_rename_extended(struct diff_options *options,
+			      struct mem_pool *pool,
 			      struct strintmap *relevant_sources,
 			      struct strintmap *dirs_removed,
 			      struct strmap *dir_rename_count,
@@ -1345,6 +1387,7 @@
 	int num_destinations, dst_cnt;
 	int num_sources, want_copies;
 	struct progress *progress = NULL;
+	struct mem_pool local_pool;
 	struct dir_rename_info info;
 	struct diff_populate_filespec_options dpf_options = {
 		.check_binary = 0,
@@ -1413,11 +1456,18 @@
 		goto cleanup; /* nothing to do */
 
 	trace2_region_enter("diff", "exact renames", options->repo);
+	mem_pool_init(&local_pool, 32*1024);
 	/*
 	 * We really want to cull the candidates list early
 	 * with cheap tests in order to avoid doing deltas.
 	 */
-	rename_count = find_exact_renames(options);
+	rename_count = find_exact_renames(options, &local_pool);
+	/*
+	 * Discard local_pool immediately instead of at "cleanup:" in order
+	 * to reduce maximum memory usage; inexact rename detection uses up
+	 * a fair amount of memory, and mem_pools can too.
+	 */
+	mem_pool_discard(&local_pool, 0);
 	trace2_region_leave("diff", "exact renames", options->repo);
 
 	/* Did we only want exact renames? */
@@ -1636,7 +1686,7 @@
 			pair_to_free = p;
 
 		if (pair_to_free)
-			diff_free_filepair(pair_to_free);
+			pool_diff_free_filepair(pool, pair_to_free);
 	}
 	diff_debug_queue("done copying original", &outq);
 
@@ -1646,7 +1696,7 @@
 
 	for (i = 0; i < rename_dst_nr; i++)
 		if (rename_dst[i].filespec_to_free)
-			free_filespec(rename_dst[i].filespec_to_free);
+			pool_free_filespec(pool, rename_dst[i].filespec_to_free);
 
 	cleanup_dir_rename_info(&info, dirs_removed, dir_rename_count != NULL);
 	FREE_AND_NULL(rename_dst);
@@ -1663,5 +1713,5 @@
 
 void diffcore_rename(struct diff_options *options)
 {
-	diffcore_rename_extended(options, NULL, NULL, NULL, NULL);
+	diffcore_rename_extended(options, NULL, NULL, NULL, NULL, NULL);
 }
diff --git a/diffcore.h b/diffcore.h
index 533b30e..badc226 100644
--- a/diffcore.h
+++ b/diffcore.h
@@ -127,6 +127,8 @@
 #define DIFF_PAIR_MODE_CHANGED(p) ((p)->one->mode != (p)->two->mode)
 
 void diff_free_filepair(struct diff_filepair *);
+void pool_diff_free_filepair(struct mem_pool *pool,
+			     struct diff_filepair *p);
 
 int diff_unmodified_pair(struct diff_filepair *);
 
@@ -179,6 +181,7 @@
 void diffcore_break(struct repository *, int);
 void diffcore_rename(struct diff_options *);
 void diffcore_rename_extended(struct diff_options *options,
+			      struct mem_pool *pool,
 			      struct strintmap *relevant_sources,
 			      struct strintmap *dirs_removed,
 			      struct strmap *dir_rename_count,
diff --git a/dir.c b/dir.c
index 03c4d21..c6d7a86 100644
--- a/dir.c
+++ b/dir.c
@@ -1294,7 +1294,7 @@
 		 * then our prefix match is all we need; we
 		 * do not need to call fnmatch at all.
 		 */
-		if (!patternlen && !namelen)
+		if (!patternlen && (!namelen || (flags & PATTERN_FLAG_MUSTBEDIR)))
 			return 1;
 	}
 
@@ -1303,6 +1303,44 @@
 				 WM_PATHNAME) == 0;
 }
 
+static int path_matches_dir_pattern(const char *pathname,
+				    int pathlen,
+				    struct strbuf **path_parent,
+				    int *dtype,
+				    struct path_pattern *pattern,
+				    struct index_state *istate)
+{
+	if (!*path_parent) {
+		char *slash;
+		CALLOC_ARRAY(*path_parent, 1);
+		strbuf_add(*path_parent, pathname, pathlen);
+		slash = find_last_dir_sep((*path_parent)->buf);
+
+		if (slash)
+			strbuf_setlen(*path_parent, slash - (*path_parent)->buf);
+		else
+			strbuf_setlen(*path_parent, 0);
+	}
+
+	/*
+	 * If the parent directory matches the pattern, then we do not
+	 * need to check for dtype.
+	 */
+	if ((*path_parent)->len &&
+	    match_pathname((*path_parent)->buf, (*path_parent)->len,
+			   pattern->base,
+			   pattern->baselen ? pattern->baselen - 1 : 0,
+			   pattern->pattern, pattern->nowildcardlen,
+			   pattern->patternlen, pattern->flags))
+		return 1;
+
+	*dtype = resolve_dtype(*dtype, istate, pathname, pathlen);
+	if (*dtype != DT_DIR)
+		return 0;
+
+	return 1;
+}
+
 /*
  * Scan the given exclude list in reverse to see whether pathname
  * should be ignored.  The first match (i.e. the last on the list), if
@@ -1318,6 +1356,7 @@
 {
 	struct path_pattern *res = NULL; /* undecided */
 	int i;
+	struct strbuf *path_parent = NULL;
 
 	if (!pl->nr)
 		return NULL;	/* undefined */
@@ -1327,11 +1366,10 @@
 		const char *exclude = pattern->pattern;
 		int prefix = pattern->nowildcardlen;
 
-		if (pattern->flags & PATTERN_FLAG_MUSTBEDIR) {
-			*dtype = resolve_dtype(*dtype, istate, pathname, pathlen);
-			if (*dtype != DT_DIR)
-				continue;
-		}
+		if (pattern->flags & PATTERN_FLAG_MUSTBEDIR &&
+		    !path_matches_dir_pattern(pathname, pathlen, &path_parent,
+					      dtype, pattern, istate))
+			continue;
 
 		if (pattern->flags & PATTERN_FLAG_NODIR) {
 			if (match_basename(basename,
@@ -1355,6 +1393,12 @@
 			break;
 		}
 	}
+
+	if (path_parent) {
+		strbuf_release(path_parent);
+		free(path_parent);
+	}
+
 	return res;
 }
 
@@ -1439,6 +1483,75 @@
 	return result;
 }
 
+int init_sparse_checkout_patterns(struct index_state *istate)
+{
+	if (!core_apply_sparse_checkout)
+		return 1;
+	if (istate->sparse_checkout_patterns)
+		return 0;
+
+	CALLOC_ARRAY(istate->sparse_checkout_patterns, 1);
+
+	if (get_sparse_checkout_patterns(istate->sparse_checkout_patterns) < 0) {
+		FREE_AND_NULL(istate->sparse_checkout_patterns);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int path_in_sparse_checkout_1(const char *path,
+				     struct index_state *istate,
+				     int require_cone_mode)
+{
+	int dtype = DT_REG;
+	enum pattern_match_result match = UNDECIDED;
+	const char *end, *slash;
+
+	/*
+	 * We default to accepting a path if there are no patterns or
+	 * they are of the wrong type.
+	 */
+	if (init_sparse_checkout_patterns(istate) ||
+	    (require_cone_mode &&
+	     !istate->sparse_checkout_patterns->use_cone_patterns))
+		return 1;
+
+	/*
+	 * If UNDECIDED, use the match from the parent dir (recursively), or
+	 * fall back to NOT_MATCHED at the topmost level. Note that cone mode
+	 * never returns UNDECIDED, so we will execute only one iteration in
+	 * this case.
+	 */
+	for (end = path + strlen(path);
+	     end > path && match == UNDECIDED;
+	     end = slash) {
+
+		for (slash = end - 1; slash > path && *slash != '/'; slash--)
+			; /* do nothing */
+
+		match = path_matches_pattern_list(path, end - path,
+				slash > path ? slash + 1 : path, &dtype,
+				istate->sparse_checkout_patterns, istate);
+
+		/* We are going to match the parent dir now */
+		dtype = DT_DIR;
+	}
+	return match > 0;
+}
+
+int path_in_sparse_checkout(const char *path,
+			    struct index_state *istate)
+{
+	return path_in_sparse_checkout_1(path, istate, 0);
+}
+
+int path_in_cone_mode_sparse_checkout(const char *path,
+				     struct index_state *istate)
+{
+	return path_in_sparse_checkout_1(path, istate, 1);
+}
+
 static struct path_pattern *last_matching_pattern_from_lists(
 		struct dir_struct *dir, struct index_state *istate,
 		const char *pathname, int pathlen,
@@ -2970,6 +3083,120 @@
 	return ret;
 }
 
+char *git_url_basename(const char *repo, int is_bundle, int is_bare)
+{
+	const char *end = repo + strlen(repo), *start, *ptr;
+	size_t len;
+	char *dir;
+
+	/*
+	 * Skip scheme.
+	 */
+	start = strstr(repo, "://");
+	if (start == NULL)
+		start = repo;
+	else
+		start += 3;
+
+	/*
+	 * Skip authentication data. The stripping does happen
+	 * greedily, such that we strip up to the last '@' inside
+	 * the host part.
+	 */
+	for (ptr = start; ptr < end && !is_dir_sep(*ptr); ptr++) {
+		if (*ptr == '@')
+			start = ptr + 1;
+	}
+
+	/*
+	 * Strip trailing spaces, slashes and /.git
+	 */
+	while (start < end && (is_dir_sep(end[-1]) || isspace(end[-1])))
+		end--;
+	if (end - start > 5 && is_dir_sep(end[-5]) &&
+	    !strncmp(end - 4, ".git", 4)) {
+		end -= 5;
+		while (start < end && is_dir_sep(end[-1]))
+			end--;
+	}
+
+	/*
+	 * Strip trailing port number if we've got only a
+	 * hostname (that is, there is no dir separator but a
+	 * colon). This check is required such that we do not
+	 * strip URI's like '/foo/bar:2222.git', which should
+	 * result in a dir '2222' being guessed due to backwards
+	 * compatibility.
+	 */
+	if (memchr(start, '/', end - start) == NULL
+	    && memchr(start, ':', end - start) != NULL) {
+		ptr = end;
+		while (start < ptr && isdigit(ptr[-1]) && ptr[-1] != ':')
+			ptr--;
+		if (start < ptr && ptr[-1] == ':')
+			end = ptr - 1;
+	}
+
+	/*
+	 * Find last component. To remain backwards compatible we
+	 * also regard colons as path separators, such that
+	 * cloning a repository 'foo:bar.git' would result in a
+	 * directory 'bar' being guessed.
+	 */
+	ptr = end;
+	while (start < ptr && !is_dir_sep(ptr[-1]) && ptr[-1] != ':')
+		ptr--;
+	start = ptr;
+
+	/*
+	 * Strip .{bundle,git}.
+	 */
+	len = end - start;
+	strip_suffix_mem(start, &len, is_bundle ? ".bundle" : ".git");
+
+	if (!len || (len == 1 && *start == '/'))
+		die(_("No directory name could be guessed.\n"
+		      "Please specify a directory on the command line"));
+
+	if (is_bare)
+		dir = xstrfmt("%.*s.git", (int)len, start);
+	else
+		dir = xstrndup(start, len);
+	/*
+	 * Replace sequences of 'control' characters and whitespace
+	 * with one ascii space, remove leading and trailing spaces.
+	 */
+	if (*dir) {
+		char *out = dir;
+		int prev_space = 1 /* strip leading whitespace */;
+		for (end = dir; *end; ++end) {
+			char ch = *end;
+			if ((unsigned char)ch < '\x20')
+				ch = '\x20';
+			if (isspace(ch)) {
+				if (prev_space)
+					continue;
+				prev_space = 1;
+			} else
+				prev_space = 0;
+			*out++ = ch;
+		}
+		*out = '\0';
+		if (out > dir && prev_space)
+			out[-1] = '\0';
+	}
+	return dir;
+}
+
+void strip_dir_trailing_slashes(char *dir)
+{
+	char *end = dir + strlen(dir);
+
+	while (dir < end - 1 && is_dir_sep(end[-1]))
+		end--;
+	*end = '\0';
+}
+
 static int remove_dir_recurse(struct strbuf *path, int flag, int *kept_up)
 {
 	DIR *dir;
@@ -3633,7 +3860,7 @@
 		strbuf_reset(&sub_wt);
 		strbuf_reset(&sub_gd);
 		strbuf_addf(&sub_wt, "%s/%s", sub_worktree, sub->path);
-		strbuf_addf(&sub_gd, "%s/modules/%s", sub_gitdir, sub->name);
+		submodule_name_to_gitdir(&sub_gd, &subrepo, sub->name);
 
 		connect_work_tree_and_git_dir(sub_wt.buf, sub_gd.buf, 1);
 	}
diff --git a/dir.h b/dir.h
index b3e1a54a..83f46c0 100644
--- a/dir.h
+++ b/dir.h
@@ -394,6 +394,14 @@
 				const char *basename, int *dtype,
 				struct pattern_list *pl,
 				struct index_state *istate);
+
+int init_sparse_checkout_patterns(struct index_state *state);
+
+int path_in_sparse_checkout(const char *path,
+			    struct index_state *istate);
+int path_in_cone_mode_sparse_checkout(const char *path,
+				      struct index_state *istate);
+
 struct dir_entry *dir_add_ignored(struct dir_struct *dir,
 				  struct index_state *istate,
 				  const char *pathname, int len);
@@ -453,6 +461,17 @@
 
 int is_empty_dir(const char *dir);
 
+/*
+ * Retrieve the "humanish" basename of the given Git URL.
+ *
+ * For example:
+ * 	/path/to/repo.git => "repo"
+ * 	host.xz:foo/.git => "foo"
+ * 	http://example.com/user/bar.baz => "bar.baz"
+ */
+char *git_url_basename(const char *repo, int is_bundle, int is_bare);
+void strip_dir_trailing_slashes(char *dir);
+
 void setup_standard_excludes(struct dir_struct *dir);
 
 char *get_sparse_checkout_filename(void);
diff --git a/editor.c b/editor.c
index 6303ae0..674309e 100644
--- a/editor.c
+++ b/editor.c
@@ -3,6 +3,7 @@
 #include "strbuf.h"
 #include "run-command.h"
 #include "sigchain.h"
+#include "compat/terminal.h"
 
 #ifndef DEFAULT_EDITOR
 #define DEFAULT_EDITOR "vi"
@@ -50,6 +51,8 @@
 static int launch_specified_editor(const char *editor, const char *path,
 				   struct strbuf *buffer, const char *const *env)
 {
+	int term_fail;
+
 	if (!editor)
 		return error("Terminal is dumb, but EDITOR unset");
 
@@ -58,7 +61,7 @@
 		const char *args[] = { editor, NULL, NULL };
 		struct child_process p = CHILD_PROCESS_INIT;
 		int ret, sig;
-		int print_waiting_for_editor = advice_waiting_for_editor && isatty(2);
+		int print_waiting_for_editor = advice_enabled(ADVICE_WAITING_FOR_EDITOR) && isatty(2);
 
 		if (print_waiting_for_editor) {
 			/*
@@ -83,7 +86,10 @@
 		p.env = env;
 		p.use_shell = 1;
 		p.trace2_child_class = "editor";
+		term_fail = save_term(1);
 		if (start_command(&p) < 0) {
+			if (!term_fail)
+				restore_term();
 			strbuf_release(&realpath);
 			return error("unable to start editor '%s'", editor);
 		}
@@ -91,6 +97,8 @@
 		sigchain_push(SIGINT, SIG_IGN);
 		sigchain_push(SIGQUIT, SIG_IGN);
 		ret = finish_command(&p);
+		if (!term_fail)
+			restore_term();
 		strbuf_release(&realpath);
 		sig = ret - 128;
 		sigchain_pop(SIGINT);
diff --git a/entry.c b/entry.c
index 044e8ec..9b0f968 100644
--- a/entry.c
+++ b/entry.c
@@ -163,24 +163,21 @@
 			    int show_progress)
 {
 	int errs = 0;
-	unsigned delayed_object_count;
+	unsigned processed_paths = 0;
 	off_t filtered_bytes = 0;
 	struct string_list_item *filter, *path;
-	struct progress *progress;
+	struct progress *progress = NULL;
 	struct delayed_checkout *dco = state->delayed_checkout;
 
 	if (!state->delayed_checkout)
 		return errs;
 
 	dco->state = CE_RETRY;
-	delayed_object_count = dco->paths.nr;
-	progress = show_progress
-		? start_delayed_progress(_("Filtering content"), delayed_object_count)
-		: NULL;
+	if (show_progress)
+		progress = start_delayed_progress(_("Filtering content"), dco->paths.nr);
 	while (dco->filters.nr > 0) {
 		for_each_string_list_item(filter, &dco->filters) {
 			struct string_list available_paths = STRING_LIST_INIT_NODUP;
-			display_progress(progress, delayed_object_count - dco->paths.nr);
 
 			if (!async_query_available_blobs(filter->string, &available_paths)) {
 				/* Filter reported an error */
@@ -227,6 +224,7 @@
 				ce = index_file_exists(state->istate, path->string,
 						       strlen(path->string), 0);
 				if (ce) {
+					display_progress(progress, ++processed_paths);
 					errs |= checkout_entry(ce, state, NULL, nr_checkouts);
 					filtered_bytes += ce->ce_stat_data.sd_size;
 					display_throughput(progress, filtered_bytes);
diff --git a/entry.h b/entry.h
index 7c889e5..2254c62 100644
--- a/entry.h
+++ b/entry.h
@@ -16,7 +16,7 @@
 		 clone:1,
 		 refresh_cache:1;
 };
-#define CHECKOUT_INIT { NULL, "" }
+#define CHECKOUT_INIT { .base_dir = "" }
 
 #define TEMPORARY_FILENAME_LENGTH 25
 /*
diff --git a/environment.c b/environment.c
index b4ba4fa..9da7f3c 100644
--- a/environment.c
+++ b/environment.c
@@ -31,7 +31,6 @@
 int is_bare_repository_cfg = -1; /* unspecified */
 int warn_ambiguous_refs = 1;
 int warn_on_object_refname_ambiguity = 1;
-int ref_paranoia = -1;
 int repository_format_precious_objects;
 int repository_format_worktree_config;
 const char *git_commit_encoding;
@@ -95,13 +94,6 @@
 /* Parallel index stat data preload? */
 int core_preload_index = 1;
 
-/*
- * This is a hack for test programs like test-dump-untracked-cache to
- * ensure that they do not modify the untracked cache when reading it.
- * Do not use it otherwise!
- */
-int ignore_untracked_cache_config;
-
 /* This is set by setup_git_dir_gently() and/or git_default_config() */
 char *git_work_tree_cfg;
 
@@ -329,8 +321,7 @@
 
 static void set_git_dir_1(const char *path)
 {
-	if (setenv(GIT_DIR_ENVIRONMENT, path, 1))
-		die(_("could not set GIT_DIR to '%s'"), path);
+	xsetenv(GIT_DIR_ENVIRONMENT, path, 1);
 	setup_git_env(path);
 }
 
diff --git a/fetch-negotiator.c b/fetch-negotiator.c
index 57ed578..2733902 100644
--- a/fetch-negotiator.c
+++ b/fetch-negotiator.c
@@ -19,7 +19,6 @@
 		return;
 
 	case FETCH_NEGOTIATION_DEFAULT:
-	default:
 		default_negotiator_init(negotiator);
 		return;
 	}
diff --git a/fetch-pack.c b/fetch-pack.c
index b0c7be7..a9604f3 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -119,6 +119,11 @@
 {
 	enum object_type type;
 	struct object_info info = { .typep = &type };
+	struct commit *commit;
+
+	commit = lookup_commit_in_graph(the_repository, oid);
+	if (commit)
+		return commit;
 
 	while (1) {
 		if (oid_object_info_extended(the_repository, oid, &info,
@@ -137,8 +142,14 @@
 			break;
 		}
 	}
-	if (type == OBJ_COMMIT)
-		return (struct commit *) parse_object(the_repository, oid);
+
+	if (type == OBJ_COMMIT) {
+		struct commit *commit = lookup_commit(the_repository, oid);
+		if (!commit || repo_parse_commit(the_repository, commit))
+			return NULL;
+		return commit;
+	}
+
 	return NULL;
 }
 
@@ -1906,16 +1917,15 @@
 	oid_array_clear(&ref);
 }
 
-static int iterate_ref_map(void *cb_data, struct object_id *oid)
+static const struct object_id *iterate_ref_map(void *cb_data)
 {
 	struct ref **rm = cb_data;
 	struct ref *ref = *rm;
 
 	if (!ref)
-		return -1; /* end of the list */
+		return NULL;
 	*rm = ref->next;
-	oidcpy(oid, &ref->old_oid);
-	return 0;
+	return &ref->old_oid;
 }
 
 struct ref *fetch_pack(struct fetch_pack_args *args,
diff --git a/fmt-merge-msg.c b/fmt-merge-msg.c
index b969dc6..5216191 100644
--- a/fmt-merge-msg.c
+++ b/fmt-merge-msg.c
@@ -9,6 +9,7 @@
 #include "branch.h"
 #include "fmt-merge-msg.h"
 #include "commit-reach.h"
+#include "gpg-interface.h"
 
 static int use_branch_desc;
 static int suppress_dest_pattern_seen;
@@ -16,6 +17,8 @@
 
 int fmt_merge_msg_config(const char *key, const char *value, void *cb)
 {
+	int status = 0;
+
 	if (!strcmp(key, "merge.log") || !strcmp(key, "merge.summary")) {
 		int is_bool;
 		merge_log_config = git_config_bool_or_int(key, value, &is_bool);
@@ -34,6 +37,9 @@
 			string_list_append(&suppress_dest_patterns, value);
 		suppress_dest_pattern_seen = 1;
 	} else {
+		status = git_gpg_config(key, value, NULL);
+		if (status)
+			return status;
 		return git_default_config(key, value, cb);
 	}
 	return 0;
@@ -528,11 +534,11 @@
 			buf = payload.buf;
 			len = payload.len;
 			if (check_signature(payload.buf, payload.len, sig.buf,
-					 sig.len, &sigc) &&
-				!sigc.gpg_output)
+					    sig.len, &sigc) &&
+			    !sigc.output)
 				strbuf_addstr(&sig, "gpg verification failed.\n");
 			else
-				strbuf_addstr(&sig, sigc.gpg_output);
+				strbuf_addstr(&sig, sigc.output);
 		}
 		signature_check_clear(&sigc);
 
diff --git a/generate-hooklist.sh b/generate-hooklist.sh
new file mode 100755
index 0000000..2f9f54e
--- /dev/null
+++ b/generate-hooklist.sh
@@ -0,0 +1,20 @@
+#!/bin/sh
+#
+# Usage: ./generate-hooklist.sh >hook-list.h
+
+cat <<EOF
+/* Automatically generated by generate-hooklist.sh */
+
+static const char *hook_name_list[] = {
+EOF
+
+sed -n \
+	-e '/^~~~~*$/ {x; s/^.*$/	"&",/; p;}' \
+	-e 'x' \
+	<Documentation/githooks.txt |
+	LC_ALL=C sort
+
+cat <<EOF
+	NULL,
+};
+EOF
diff --git a/gettext.h b/gettext.h
index c8b34fd..d209911 100644
--- a/gettext.h
+++ b/gettext.h
@@ -55,31 +55,7 @@
 }
 
 /* Mark msgid for translation but do not translate it. */
-#if !USE_PARENS_AROUND_GETTEXT_N
 #define N_(msgid) msgid
-#else
-/*
- * Strictly speaking, this will lead to invalid C when
- * used this way:
- *	static const char s[] = N_("FOO");
- * which will expand to
- *	static const char s[] = ("FOO");
- * and in valid C, the initializer on the right hand side must
- * be without the parentheses.  But many compilers do accept it
- * as a language extension and it will allow us to catch mistakes
- * like:
- *	static const char *msgs[] = {
- *		N_("one")
- *		N_("two"),
- *		N_("three"),
- *		NULL
- *	};
- * (notice the missing comma on one of the lines) by forcing
- * a compilation error, because parenthesised ("one") ("two")
- * will not get silently turned into ("onetwo").
- */
-#define N_(msgid) (msgid)
-#endif
 
 const char *get_preferred_languages(void);
 int is_utf8_locale(void);
diff --git a/git-bisect.sh b/git-bisect.sh
index 6a7afae..405cf76 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -34,94 +34,9 @@
 OPTIONS_SPEC=
 . git-sh-setup
 
-_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 TERM_BAD=bad
 TERM_GOOD=good
 
-bisect_visualize() {
-	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD fail || exit
-
-	if test $# = 0
-	then
-		if test -n "${DISPLAY+set}${SESSIONNAME+set}${MSYSTEM+set}${SECURITYSESSIONID+set}" &&
-			type gitk >/dev/null 2>&1
-		then
-			set gitk
-		else
-			set git log
-		fi
-	else
-		case "$1" in
-		git*|tig) ;;
-		-*)	set git log "$@" ;;
-		*)	set git "$@" ;;
-		esac
-	fi
-
-	eval '"$@"' --bisect -- $(cat "$GIT_DIR/BISECT_NAMES")
-}
-
-bisect_run () {
-	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD fail || exit
-
-	test -n "$*" || die "$(gettext "bisect run failed: no command provided.")"
-
-	while true
-	do
-		command="$@"
-		eval_gettextln "running \$command"
-		"$@"
-		res=$?
-
-		# Check for really bad run error.
-		if [ $res -lt 0 -o $res -ge 128 ]
-		then
-			eval_gettextln "bisect run failed:
-exit code \$res from '\$command' is < 0 or >= 128" >&2
-			exit $res
-		fi
-
-		# Find current state depending on run success or failure.
-		# A special exit code of 125 means cannot test.
-		if [ $res -eq 125 ]
-		then
-			state='skip'
-		elif [ $res -gt 0 ]
-		then
-			state="$TERM_BAD"
-		else
-			state="$TERM_GOOD"
-		fi
-
-		git bisect--helper --bisect-state $state >"$GIT_DIR/BISECT_RUN"
-		res=$?
-
-		cat "$GIT_DIR/BISECT_RUN"
-
-		if sane_grep "first $TERM_BAD commit could be any of" "$GIT_DIR/BISECT_RUN" \
-			>/dev/null
-		then
-			gettextln "bisect run cannot continue any more" >&2
-			exit $res
-		fi
-
-		if [ $res -ne 0 ]
-		then
-			eval_gettextln "bisect run failed:
-'bisect-state \$state' exited with error code \$res" >&2
-			exit $res
-		fi
-
-		if sane_grep "is the first $TERM_BAD commit" "$GIT_DIR/BISECT_RUN" >/dev/null
-		then
-			gettextln "bisect run success"
-			exit 0;
-		fi
-
-	done
-}
-
 get_terms () {
 	if test -s "$GIT_DIR/BISECT_TERMS"
 	then
@@ -152,7 +67,7 @@
 		# Not sure we want "next" at the UI level anymore.
 		git bisect--helper --bisect-next "$@" || exit ;;
 	visualize|view)
-		bisect_visualize "$@" ;;
+		git bisect--helper --bisect-visualize "$@" || exit;;
 	reset)
 		git bisect--helper --bisect-reset "$@" ;;
 	replay)
@@ -160,7 +75,7 @@
 	log)
 		git bisect--helper --bisect-log || exit ;;
 	run)
-		bisect_run "$@" ;;
+		git bisect--helper --bisect-run "$@" || exit;;
 	terms)
 		git bisect--helper --bisect-terms "$@" || exit;;
 	*)
diff --git a/git-compat-util.h b/git-compat-util.h
index b466053..d70ce14 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -160,6 +160,9 @@
 # endif
 #define WIN32_LEAN_AND_MEAN  /* stops windows.h including winsock.h */
 #include <winsock2.h>
+#ifndef NO_UNIX_SOCKETS
+#include <afunix.h>
+#endif
 #include <windows.h>
 #define GIT_WINDOWS_NATIVE
 #endif
@@ -875,6 +878,7 @@
 char *xstrndup(const char *str, size_t len);
 void *xrealloc(void *ptr, size_t size);
 void *xcalloc(size_t nmemb, size_t size);
+void xsetenv(const char *name, const char *value, int overwrite);
 void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
 const char *mmap_os_err(void);
 void *xmmap_gently(void *start, size_t length, int prot, int flags, int fd, off_t offset);
@@ -1253,10 +1257,6 @@
  */
 int open_nofollow(const char *path, int flags);
 
-#if !defined(USE_PARENS_AROUND_GETTEXT_N) && defined(__GNUC__)
-#define USE_PARENS_AROUND_GETTEXT_N 1
-#endif
-
 #ifndef SHELL_PATH
 # define SHELL_PATH "/bin/sh"
 #endif
diff --git a/git-curl-compat.h b/git-curl-compat.h
new file mode 100644
index 0000000..56a83b6
--- /dev/null
+++ b/git-curl-compat.h
@@ -0,0 +1,129 @@
+#ifndef GIT_CURL_COMPAT_H
+#define GIT_CURL_COMPAT_H
+#include <curl/curl.h>
+
+/**
+ * This header centralizes the declaration of our libcurl dependencies
+ * to make it easy to discover the oldest versions we support, and to
+ * inform decisions about removing support for older libcurl in the
+ * future.
+ *
+ * The oldest supported version of curl is documented in the "INSTALL"
+ * document.
+ *
+ * The source of truth for what versions have which symbols is
+ * https://github.com/curl/curl/blob/master/docs/libcurl/symbols-in-versions;
+ * the release dates are taken from curl.git (at
+ * https://github.com/curl/curl/).
+ *
+ * For each X symbol we need from curl we define our own
+ * GIT_CURL_HAVE_X. If multiple similar symbols with the same prefix
+ * were defined in the same version we pick one and check for that name.
+ *
+ * We may also define a missing CURL_* symbol to its known value, if
+ * doing so is sufficient to add support for it to older versions that
+ * don't have it.
+ *
+ * Keep any symbols in date order of when their support was
+ * introduced, oldest first, in the official version of cURL library.
+ */
+
+/**
+ * CURL_SOCKOPT_OK was added in 7.21.5, released in April 2011.
+ */
+#if LIBCURL_VERSION_NUM < 0x071505
+#define CURL_SOCKOPT_OK 0
+#endif
+
+/**
+ * CURLOPT_TCP_KEEPALIVE was added in 7.25.0, released in March 2012.
+ */
+#if LIBCURL_VERSION_NUM >= 0x071900
+#define GITCURL_HAVE_CURLOPT_TCP_KEEPALIVE 1
+#endif
+
+
+/**
+ * CURLOPT_LOGIN_OPTIONS was added in 7.34.0, released in December
+ * 2013.
+ *
+ * If we start requiring 7.34.0 we might also be able to remove the
+ * code conditional on USE_CURL_FOR_IMAP_SEND in imap-send.c, see
+ * 1e16b255b95 (git-imap-send: use libcurl for implementation,
+ * 2014-11-09) and the check it added for "072200" in the Makefile.
+
+ */
+#if LIBCURL_VERSION_NUM >= 0x072200
+#define GIT_CURL_HAVE_CURLOPT_LOGIN_OPTIONS 1
+#endif
+
+/**
+ * CURL_SSLVERSION_TLSv1_[012] was added in 7.34.0, released in
+ * December 2013.
+ */
+#if LIBCURL_VERSION_NUM >= 0x072200
+#define GIT_CURL_HAVE_CURL_SSLVERSION_TLSv1_0
+#endif
+
+/**
+ * CURLOPT_PINNEDPUBLICKEY was added in 7.39.0, released in November
+ * 2014. CURLE_SSL_PINNEDPUBKEYNOTMATCH was added in that same version.
+ */
+#if LIBCURL_VERSION_NUM >= 0x072c00
+#define GIT_CURL_HAVE_CURLOPT_PINNEDPUBLICKEY 1
+#define GIT_CURL_HAVE_CURLE_SSL_PINNEDPUBKEYNOTMATCH 1
+#endif
+
+/**
+ * CURL_HTTP_VERSION_2 was added in 7.43.0, released in June 2015.
+ *
+ * The CURL_HTTP_VERSION_2 alias (but not CURL_HTTP_VERSION_2_0) has
+ * always been a macro, not an enum field (checked on curl version
+ * 7.78.0)
+ */
+#if LIBCURL_VERSION_NUM >= 0x072b00
+#define GIT_CURL_HAVE_CURL_HTTP_VERSION_2 1
+#endif
+
+/**
+ * CURLSSLOPT_NO_REVOKE was added in 7.44.0, released in August 2015.
+ *
+ * The CURLSSLOPT_NO_REVOKE is, has always been a macro, not an enum
+ * field (checked on curl version 7.78.0)
+ */
+#if LIBCURL_VERSION_NUM >= 0x072c00
+#define GIT_CURL_HAVE_CURLSSLOPT_NO_REVOKE 1
+#endif
+
+/**
+ * CURLOPT_PROXY_CAINFO was added in 7.52.0, released in August 2017.
+ */
+#if LIBCURL_VERSION_NUM >= 0x073400
+#define GIT_CURL_HAVE_CURLOPT_PROXY_CAINFO 1
+#endif
+
+/**
+ * CURLOPT_PROXY_{KEYPASSWD,SSLCERT,SSLKEY} was added in 7.52.0,
+ * released in August 2017.
+ */
+#if LIBCURL_VERSION_NUM >= 0x073400
+#define GIT_CURL_HAVE_CURLOPT_PROXY_KEYPASSWD 1
+#endif
+
+/**
+ * CURL_SSLVERSION_TLSv1_3 was added in 7.53.0, released in February
+ * 2017.
+ */
+#if LIBCURL_VERSION_NUM >= 0x073400
+#define GIT_CURL_HAVE_CURL_SSLVERSION_TLSv1_3 1
+#endif
+
+/**
+ * CURLSSLSET_{NO_BACKENDS,OK,TOO_LATE,UNKNOWN_BACKEND} were added in
+ * 7.56.0, released in September 2017.
+ */
+#if LIBCURL_VERSION_NUM >= 0x073800
+#define GIT_CURL_HAVE_CURLSSLSET_NO_BACKENDS
+#endif
+
+#endif
diff --git a/git-rebase--preserve-merges.sh b/git-rebase--preserve-merges.sh
deleted file mode 100644
index b9c71d2..0000000
--- a/git-rebase--preserve-merges.sh
+++ /dev/null
@@ -1,1057 +0,0 @@
-# This shell script fragment is sourced by git-rebase to implement its
-# preserve-merges mode.
-#
-# Copyright (c) 2006 Johannes E. Schindelin
-#
-# The file containing rebase commands, comments, and empty lines.
-# This file is created by "git rebase -i" then edited by the user.  As
-# the lines are processed, they are removed from the front of this
-# file and written to the tail of $done.
-todo="$state_dir"/git-rebase-todo
-
-# The rebase command lines that have already been processed.  A line
-# is moved here when it is first handled, before any associated user
-# actions.
-done="$state_dir"/done
-
-# The commit message that is planned to be used for any changes that
-# need to be committed following a user interaction.
-msg="$state_dir"/message
-
-# The file into which is accumulated the suggested commit message for
-# squash/fixup commands.  When the first of a series of squash/fixups
-# is seen, the file is created and the commit message from the
-# previous commit and from the first squash/fixup commit are written
-# to it.  The commit message for each subsequent squash/fixup commit
-# is appended to the file as it is processed.
-#
-# The first line of the file is of the form
-#     # This is a combination of $count commits.
-# where $count is the number of commits whose messages have been
-# written to the file so far (including the initial "pick" commit).
-# Each time that a commit message is processed, this line is read and
-# updated.  It is deleted just before the combined commit is made.
-squash_msg="$state_dir"/message-squash
-
-# If the current series of squash/fixups has not yet included a squash
-# command, then this file exists and holds the commit message of the
-# original "pick" commit.  (If the series ends without a "squash"
-# command, then this can be used as the commit message of the combined
-# commit without opening the editor.)
-fixup_msg="$state_dir"/message-fixup
-
-# $rewritten is the name of a directory containing files for each
-# commit that is reachable by at least one merge base of $head and
-# $upstream. They are not necessarily rewritten, but their children
-# might be.  This ensures that commits on merged, but otherwise
-# unrelated side branches are left alone. (Think "X" in the man page's
-# example.)
-rewritten="$state_dir"/rewritten
-
-dropped="$state_dir"/dropped
-
-end="$state_dir"/end
-msgnum="$state_dir"/msgnum
-
-# A script to set the GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
-# GIT_AUTHOR_DATE that will be used for the commit that is currently
-# being rebased.
-author_script="$state_dir"/author-script
-
-# When an "edit" rebase command is being processed, the SHA1 of the
-# commit to be edited is recorded in this file.  When "git rebase
-# --continue" is executed, if there are any staged changes then they
-# will be amended to the HEAD commit, but only provided the HEAD
-# commit is still the commit to be edited.  When any other rebase
-# command is processed, this file is deleted.
-amend="$state_dir"/amend
-
-# For the post-rewrite hook, we make a list of rewritten commits and
-# their new sha1s.  The rewritten-pending list keeps the sha1s of
-# commits that have been processed, but not committed yet,
-# e.g. because they are waiting for a 'squash' command.
-rewritten_list="$state_dir"/rewritten-list
-rewritten_pending="$state_dir"/rewritten-pending
-
-# Work around Git for Windows' Bash whose "read" does not strip CRLF
-# and leaves CR at the end instead.
-cr=$(printf "\015")
-
-resolvemsg="
-$(gettext 'Resolve all conflicts manually, mark them as resolved with
-"git add/rm <conflicted_files>", then run "git rebase --continue".
-You can instead skip this commit: run "git rebase --skip".
-To abort and get back to the state before "git rebase", run "git rebase --abort".')
-"
-
-write_basic_state () {
-	echo "$head_name" > "$state_dir"/head-name &&
-	echo "$onto" > "$state_dir"/onto &&
-	echo "$orig_head" > "$state_dir"/orig-head &&
-	test t = "$GIT_QUIET" && : > "$state_dir"/quiet
-	test t = "$verbose" && : > "$state_dir"/verbose
-	test -n "$strategy" && echo "$strategy" > "$state_dir"/strategy
-	test -n "$strategy_opts" && echo "$strategy_opts" > \
-		"$state_dir"/strategy_opts
-	test -n "$allow_rerere_autoupdate" && echo "$allow_rerere_autoupdate" > \
-		"$state_dir"/allow_rerere_autoupdate
-	test -n "$gpg_sign_opt" && echo "$gpg_sign_opt" > "$state_dir"/gpg_sign_opt
-	test -n "$signoff" && echo "$signoff" >"$state_dir"/signoff
-	test -n "$reschedule_failed_exec" && : > "$state_dir"/reschedule-failed-exec
-}
-
-apply_autostash () {
-	if test -f "$state_dir/autostash"
-	then
-		stash_sha1=$(cat "$state_dir/autostash")
-		if git stash apply $stash_sha1 >/dev/null 2>&1
-		then
-			echo "$(gettext 'Applied autostash.')" >&2
-		else
-			git stash store -m "autostash" -q $stash_sha1 ||
-			die "$(eval_gettext "Cannot store \$stash_sha1")"
-			gettext 'Applying autostash resulted in conflicts.
-Your changes are safe in the stash.
-You can run "git stash pop" or "git stash drop" at any time.
-' >&2
-		fi
-	fi
-}
-
-output () {
-	case "$verbose" in
-	'')
-		output=$("$@" 2>&1 )
-		status=$?
-		test $status != 0 && printf "%s\n" "$output"
-		return $status
-		;;
-	*)
-		"$@"
-		;;
-	esac
-}
-
-strategy_args=${strategy:+--strategy=$strategy}
-test -n "$strategy_opts" &&
-eval '
-	for strategy_opt in '"$strategy_opts"'
-	do
-		strategy_args="$strategy_args -X$(git rev-parse --sq-quote "${strategy_opt#--}")"
-	done
-'
-
-GIT_CHERRY_PICK_HELP="$resolvemsg"
-export GIT_CHERRY_PICK_HELP
-
-comment_char=$(git config --get core.commentchar 2>/dev/null)
-case "$comment_char" in
-'' | auto)
-	comment_char="#"
-	;;
-?)
-	;;
-*)
-	comment_char=$(echo "$comment_char" | cut -c1)
-	;;
-esac
-
-warn () {
-	printf '%s\n' "$*" >&2
-}
-
-# Output the commit message for the specified commit.
-commit_message () {
-	git cat-file commit "$1" | sed "1,/^$/d"
-}
-
-orig_reflog_action="$GIT_REFLOG_ACTION"
-
-comment_for_reflog () {
-	case "$orig_reflog_action" in
-	''|rebase*)
-		GIT_REFLOG_ACTION="rebase -i ($1)"
-		export GIT_REFLOG_ACTION
-		;;
-	esac
-}
-
-last_count=
-mark_action_done () {
-	sed -e 1q < "$todo" >> "$done"
-	sed -e 1d < "$todo" >> "$todo".new
-	mv -f "$todo".new "$todo"
-	new_count=$(( $(git stripspace --strip-comments <"$done" | wc -l) ))
-	echo $new_count >"$msgnum"
-	total=$(($new_count + $(git stripspace --strip-comments <"$todo" | wc -l)))
-	echo $total >"$end"
-	if test "$last_count" != "$new_count"
-	then
-		last_count=$new_count
-		eval_gettext "Rebasing (\$new_count/\$total)"; printf "\r"
-		test -z "$verbose" || echo
-	fi
-}
-
-append_todo_help () {
-	gettext "
-Commands:
-p, pick <commit> = use commit
-r, reword <commit> = use commit, but edit the commit message
-e, edit <commit> = use commit, but stop for amending
-s, squash <commit> = use commit, but meld into previous commit
-f, fixup <commit> = like \"squash\", but discard this commit's log message
-x, exec <commit> = run command (the rest of the line) using shell
-d, drop <commit> = remove commit
-l, label <label> = label current HEAD with a name
-t, reset <label> = reset HEAD to a label
-m, merge [-C <commit> | -c <commit>] <label> [# <oneline>]
-.       create a merge commit using the original merge commit's
-.       message (or the oneline, if no original merge commit was
-.       specified). Use -c <commit> to reword the commit message.
-
-These lines can be re-ordered; they are executed from top to bottom.
-" | git stripspace --comment-lines >>"$todo"
-
-	if test $(get_missing_commit_check_level) = error
-	then
-		gettext "
-Do not remove any line. Use 'drop' explicitly to remove a commit.
-" | git stripspace --comment-lines >>"$todo"
-	else
-		gettext "
-If you remove a line here THAT COMMIT WILL BE LOST.
-" | git stripspace --comment-lines >>"$todo"
-	fi
-}
-
-make_patch () {
-	sha1_and_parents="$(git rev-list --parents -1 "$1")"
-	case "$sha1_and_parents" in
-	?*' '?*' '?*)
-		git diff --cc $sha1_and_parents
-		;;
-	?*' '?*)
-		git diff-tree -p "$1^!"
-		;;
-	*)
-		echo "Root commit"
-		;;
-	esac > "$state_dir"/patch
-	test -f "$msg" ||
-		commit_message "$1" > "$msg"
-	test -f "$author_script" ||
-		get_author_ident_from_commit "$1" > "$author_script"
-}
-
-die_with_patch () {
-	echo "$1" > "$state_dir"/stopped-sha
-	git update-ref REBASE_HEAD "$1"
-	make_patch "$1"
-	die "$2"
-}
-
-exit_with_patch () {
-	echo "$1" > "$state_dir"/stopped-sha
-	git update-ref REBASE_HEAD "$1"
-	make_patch $1
-	git rev-parse --verify HEAD > "$amend"
-	gpg_sign_opt_quoted=${gpg_sign_opt:+$(git rev-parse --sq-quote "$gpg_sign_opt")}
-	warn "$(eval_gettext "\
-You can amend the commit now, with
-
-	git commit --amend \$gpg_sign_opt_quoted
-
-Once you are satisfied with your changes, run
-
-	git rebase --continue")"
-	warn
-	exit $2
-}
-
-die_abort () {
-	apply_autostash
-	rm -rf "$state_dir"
-	die "$1"
-}
-
-has_action () {
-	test -n "$(git stripspace --strip-comments <"$1")"
-}
-
-is_empty_commit() {
-	tree=$(git rev-parse -q --verify "$1"^{tree} 2>/dev/null) || {
-		sha1=$1
-		die "$(eval_gettext "\$sha1: not a commit that can be picked")"
-	}
-	ptree=$(git rev-parse -q --verify "$1"^^{tree} 2>/dev/null) ||
-		ptree=4b825dc642cb6eb9a060e54bf8d69288fbee4904
-	test "$tree" = "$ptree"
-}
-
-is_merge_commit()
-{
-	git rev-parse --verify --quiet "$1"^2 >/dev/null 2>&1
-}
-
-# Run command with GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
-# GIT_AUTHOR_DATE exported from the current environment.
-do_with_author () {
-	(
-		export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE
-		"$@"
-	)
-}
-
-git_sequence_editor () {
-	if test -z "$GIT_SEQUENCE_EDITOR"
-	then
-		GIT_SEQUENCE_EDITOR="$(git config sequence.editor)"
-		if [ -z "$GIT_SEQUENCE_EDITOR" ]
-		then
-			GIT_SEQUENCE_EDITOR="$(git var GIT_EDITOR)" || return $?
-		fi
-	fi
-
-	eval "$GIT_SEQUENCE_EDITOR" '"$@"'
-}
-
-pick_one () {
-	ff=--ff
-
-	case "$1" in -n) sha1=$2; ff= ;; *) sha1=$1 ;; esac
-	case "$force_rebase" in '') ;; ?*) ff= ;; esac
-	output git rev-parse --verify $sha1 || die "$(eval_gettext "Invalid commit name: \$sha1")"
-
-	if is_empty_commit "$sha1"
-	then
-		empty_args="--allow-empty"
-	fi
-
-	pick_one_preserving_merges "$@"
-}
-
-pick_one_preserving_merges () {
-	fast_forward=t
-	case "$1" in
-	-n)
-		fast_forward=f
-		sha1=$2
-		;;
-	*)
-		sha1=$1
-		;;
-	esac
-	sha1=$(git rev-parse $sha1)
-
-	if test -f "$state_dir"/current-commit && test "$fast_forward" = t
-	then
-		while read current_commit
-		do
-			git rev-parse HEAD > "$rewritten"/$current_commit
-		done <"$state_dir"/current-commit
-		rm "$state_dir"/current-commit ||
-			die "$(gettext "Cannot write current commit's replacement sha1")"
-	fi
-
-	echo $sha1 >> "$state_dir"/current-commit
-
-	# rewrite parents; if none were rewritten, we can fast-forward.
-	new_parents=
-	pend=" $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)"
-	if test "$pend" = " "
-	then
-		pend=" root"
-	fi
-	while [ "$pend" != "" ]
-	do
-		p=$(expr "$pend" : ' \([^ ]*\)')
-		pend="${pend# $p}"
-
-		if test -f "$rewritten"/$p
-		then
-			new_p=$(cat "$rewritten"/$p)
-
-			# If the todo reordered commits, and our parent is marked for
-			# rewriting, but hasn't been gotten to yet, assume the user meant to
-			# drop it on top of the current HEAD
-			if test -z "$new_p"
-			then
-				new_p=$(git rev-parse HEAD)
-			fi
-
-			test $p != $new_p && fast_forward=f
-			case "$new_parents" in
-			*$new_p*)
-				;; # do nothing; that parent is already there
-			*)
-				new_parents="$new_parents $new_p"
-				;;
-			esac
-		else
-			if test -f "$dropped"/$p
-			then
-				fast_forward=f
-				replacement="$(cat "$dropped"/$p)"
-				test -z "$replacement" && replacement=root
-				pend=" $replacement$pend"
-			else
-				new_parents="$new_parents $p"
-			fi
-		fi
-	done
-	case $fast_forward in
-	t)
-		output warn "$(eval_gettext "Fast-forward to \$sha1")"
-		output git reset --hard $sha1 ||
-			die "$(eval_gettext "Cannot fast-forward to \$sha1")"
-		;;
-	f)
-		first_parent=$(expr "$new_parents" : ' \([^ ]*\)')
-
-		if [ "$1" != "-n" ]
-		then
-			# detach HEAD to current parent
-			output git checkout $first_parent 2> /dev/null ||
-				die "$(eval_gettext "Cannot move HEAD to \$first_parent")"
-		fi
-
-		case "$new_parents" in
-		' '*' '*)
-			test "a$1" = a-n && die "$(eval_gettext "Refusing to squash a merge: \$sha1")"
-
-			# redo merge
-			author_script_content=$(get_author_ident_from_commit $sha1)
-			eval "$author_script_content"
-			msg_content="$(commit_message $sha1)"
-			# No point in merging the first parent, that's HEAD
-			new_parents=${new_parents# $first_parent}
-			merge_args="--no-log --no-ff"
-			if ! do_with_author output eval \
-				git merge ${gpg_sign_opt:+$(git rev-parse \
-					--sq-quote "$gpg_sign_opt")} \
-				$allow_rerere_autoupdate "$merge_args" \
-				"$strategy_args" \
-				-m "$(git rev-parse --sq-quote "$msg_content")" \
-				"$new_parents"
-			then
-				printf "%s\n" "$msg_content" > "$GIT_DIR"/MERGE_MSG
-				die_with_patch $sha1 "$(eval_gettext "Error redoing merge \$sha1")"
-			fi
-			echo "$sha1 $(git rev-parse HEAD^0)" >> "$rewritten_list"
-			;;
-		*)
-			output eval git cherry-pick $allow_rerere_autoupdate \
-				$allow_empty_message \
-				${gpg_sign_opt:+$(git rev-parse --sq-quote "$gpg_sign_opt")} \
-				"$strategy_args" "$@" ||
-				die_with_patch $sha1 "$(eval_gettext "Could not pick \$sha1")"
-			;;
-		esac
-		;;
-	esac
-}
-
-this_nth_commit_message () {
-	n=$1
-	eval_gettext "This is the commit message #\${n}:"
-}
-
-skip_nth_commit_message () {
-	n=$1
-	eval_gettext "The commit message #\${n} will be skipped:"
-}
-
-update_squash_messages () {
-	if test -f "$squash_msg"; then
-		mv "$squash_msg" "$squash_msg".bak || exit
-		count=$(($(sed -n \
-			-e "1s/^$comment_char[^0-9]*\([0-9][0-9]*\).*/\1/p" \
-			-e "q" < "$squash_msg".bak)+1))
-		{
-			printf '%s\n' "$comment_char $(eval_ngettext \
-				"This is a combination of \$count commit." \
-				"This is a combination of \$count commits." \
-				$count)"
-			sed -e 1d -e '2,/^./{
-				/^$/d
-			}' <"$squash_msg".bak
-		} >"$squash_msg"
-	else
-		commit_message HEAD >"$fixup_msg" ||
-		die "$(eval_gettext "Cannot write \$fixup_msg")"
-		count=2
-		{
-			printf '%s\n' "$comment_char $(gettext "This is a combination of 2 commits.")"
-			printf '%s\n' "$comment_char $(gettext "This is the 1st commit message:")"
-			echo
-			cat "$fixup_msg"
-		} >"$squash_msg"
-	fi
-	case $1 in
-	squash)
-		rm -f "$fixup_msg"
-		echo
-		printf '%s\n' "$comment_char $(this_nth_commit_message $count)"
-		echo
-		commit_message $2
-		;;
-	fixup)
-		echo
-		printf '%s\n' "$comment_char $(skip_nth_commit_message $count)"
-		echo
-		# Change the space after the comment character to TAB:
-		commit_message $2 | git stripspace --comment-lines | sed -e 's/ /	/'
-		;;
-	esac >>"$squash_msg"
-}
-
-peek_next_command () {
-	git stripspace --strip-comments <"$todo" | sed -n -e 's/ .*//p' -e q
-}
-
-# A squash/fixup has failed.  Prepare the long version of the squash
-# commit message, then die_with_patch.  This code path requires the
-# user to edit the combined commit message for all commits that have
-# been squashed/fixedup so far.  So also erase the old squash
-# messages, effectively causing the combined commit to be used as the
-# new basis for any further squash/fixups.  Args: sha1 rest
-die_failed_squash() {
-	sha1=$1
-	rest=$2
-	mv "$squash_msg" "$msg" || exit
-	rm -f "$fixup_msg"
-	cp "$msg" "$GIT_DIR"/MERGE_MSG || exit
-	warn
-	warn "$(eval_gettext "Could not apply \$sha1... \$rest")"
-	die_with_patch $sha1 ""
-}
-
-flush_rewritten_pending() {
-	test -s "$rewritten_pending" || return
-	newsha1="$(git rev-parse HEAD^0)"
-	sed "s/$/ $newsha1/" < "$rewritten_pending" >> "$rewritten_list"
-	rm -f "$rewritten_pending"
-}
-
-record_in_rewritten() {
-	oldsha1="$(git rev-parse $1)"
-	echo "$oldsha1" >> "$rewritten_pending"
-
-	case "$(peek_next_command)" in
-	squash|s|fixup|f)
-		;;
-	*)
-		flush_rewritten_pending
-		;;
-	esac
-}
-
-do_pick () {
-	sha1=$1
-	rest=$2
-	if test "$(git rev-parse HEAD)" = "$squash_onto"
-	then
-		# Set the correct commit message and author info on the
-		# sentinel root before cherry-picking the original changes
-		# without committing (-n).  Finally, update the sentinel again
-		# to include these changes.  If the cherry-pick results in a
-		# conflict, this means our behaviour is similar to a standard
-		# failed cherry-pick during rebase, with a dirty index to
-		# resolve before manually running git commit --amend then git
-		# rebase --continue.
-		git commit --allow-empty --allow-empty-message --amend \
-			   --no-post-rewrite -n -q -C $sha1 $signoff &&
-			pick_one -n $sha1 &&
-			git commit --allow-empty --allow-empty-message \
-				   --amend --no-post-rewrite -n -q -C $sha1 $signoff \
-				   ${gpg_sign_opt:+"$gpg_sign_opt"} ||
-				   die_with_patch $sha1 "$(eval_gettext "Could not apply \$sha1... \$rest")"
-	else
-		pick_one $sha1 ||
-			die_with_patch $sha1 "$(eval_gettext "Could not apply \$sha1... \$rest")"
-	fi
-}
-
-do_next () {
-	rm -f "$msg" "$author_script" "$amend" "$state_dir"/stopped-sha || exit
-	read -r command sha1 rest < "$todo"
-	case "$command" in
-	"$comment_char"*|''|noop|drop|d)
-		mark_action_done
-		;;
-	"$cr")
-		# Work around CR left by "read" (e.g. with Git for Windows' Bash).
-		mark_action_done
-		;;
-	pick|p)
-		comment_for_reflog pick
-
-		mark_action_done
-		do_pick $sha1 "$rest"
-		record_in_rewritten $sha1
-		;;
-	reword|r)
-		comment_for_reflog reword
-
-		mark_action_done
-		do_pick $sha1 "$rest"
-		git commit --amend --no-post-rewrite ${gpg_sign_opt:+"$gpg_sign_opt"} \
-			$allow_empty_message || {
-			warn "$(eval_gettext "\
-Could not amend commit after successfully picking \$sha1... \$rest
-This is most likely due to an empty commit message, or the pre-commit hook
-failed. If the pre-commit hook failed, you may need to resolve the issue before
-you are able to reword the commit.")"
-			exit_with_patch $sha1 1
-		}
-		record_in_rewritten $sha1
-		;;
-	edit|e)
-		comment_for_reflog edit
-
-		mark_action_done
-		do_pick $sha1 "$rest"
-		sha1_abbrev=$(git rev-parse --short $sha1)
-		warn "$(eval_gettext "Stopped at \$sha1_abbrev... \$rest")"
-		exit_with_patch $sha1 0
-		;;
-	squash|s|fixup|f)
-		case "$command" in
-		squash|s)
-			squash_style=squash
-			;;
-		fixup|f)
-			squash_style=fixup
-			;;
-		esac
-		comment_for_reflog $squash_style
-
-		test -f "$done" && has_action "$done" ||
-			die "$(eval_gettext "Cannot '\$squash_style' without a previous commit")"
-
-		mark_action_done
-		update_squash_messages $squash_style $sha1
-		author_script_content=$(get_author_ident_from_commit HEAD)
-		echo "$author_script_content" > "$author_script"
-		eval "$author_script_content"
-		if ! pick_one -n $sha1
-		then
-			git rev-parse --verify HEAD >"$amend"
-			die_failed_squash $sha1 "$rest"
-		fi
-		case "$(peek_next_command)" in
-		squash|s|fixup|f)
-			# This is an intermediate commit; its message will only be
-			# used in case of trouble.  So use the long version:
-			do_with_author output git commit --amend --no-verify -F "$squash_msg" \
-				${gpg_sign_opt:+"$gpg_sign_opt"} $allow_empty_message ||
-				die_failed_squash $sha1 "$rest"
-			;;
-		*)
-			# This is the final command of this squash/fixup group
-			if test -f "$fixup_msg"
-			then
-				do_with_author git commit --amend --no-verify -F "$fixup_msg" \
-					${gpg_sign_opt:+"$gpg_sign_opt"} $allow_empty_message ||
-					die_failed_squash $sha1 "$rest"
-			else
-				cp "$squash_msg" "$GIT_DIR"/SQUASH_MSG || exit
-				rm -f "$GIT_DIR"/MERGE_MSG
-				do_with_author git commit --amend --no-verify -F "$GIT_DIR"/SQUASH_MSG -e \
-					${gpg_sign_opt:+"$gpg_sign_opt"} $allow_empty_message ||
-					die_failed_squash $sha1 "$rest"
-			fi
-			rm -f "$squash_msg" "$fixup_msg"
-			;;
-		esac
-		record_in_rewritten $sha1
-		;;
-	x|"exec")
-		read -r command rest < "$todo"
-		mark_action_done
-		eval_gettextln "Executing: \$rest"
-		"${SHELL:-@SHELL_PATH@}" -c "$rest" # Actual execution
-		status=$?
-		# Run in subshell because require_clean_work_tree can die.
-		dirty=f
-		(require_clean_work_tree "rebase" 2>/dev/null) || dirty=t
-		if test "$status" -ne 0
-		then
-			warn "$(eval_gettext "Execution failed: \$rest")"
-			test "$dirty" = f ||
-				warn "$(gettext "and made changes to the index and/or the working tree")"
-
-			warn "$(gettext "\
-You can fix the problem, and then run
-
-	git rebase --continue")"
-			warn
-			if test $status -eq 127		# command not found
-			then
-				status=1
-			fi
-			exit "$status"
-		elif test "$dirty" = t
-		then
-			# TRANSLATORS: after these lines is a command to be issued by the user
-			warn "$(eval_gettext "\
-Execution succeeded: \$rest
-but left changes to the index and/or the working tree
-Commit or stash your changes, and then run
-
-	git rebase --continue")"
-			warn
-			exit 1
-		fi
-		;;
-	*)
-		warn "$(eval_gettext "Unknown command: \$command \$sha1 \$rest")"
-		fixtodo="$(gettext "Please fix this using 'git rebase --edit-todo'.")"
-		if git rev-parse --verify -q "$sha1" >/dev/null
-		then
-			die_with_patch $sha1 "$fixtodo"
-		else
-			die "$fixtodo"
-		fi
-		;;
-	esac
-	test -s "$todo" && return
-
-	comment_for_reflog finish &&
-	newhead=$(git rev-parse HEAD) &&
-	case $head_name in
-	refs/*)
-		message="$GIT_REFLOG_ACTION: $head_name onto $onto" &&
-		git update-ref -m "$message" $head_name $newhead $orig_head &&
-		git symbolic-ref \
-		  -m "$GIT_REFLOG_ACTION: returning to $head_name" \
-		  HEAD $head_name
-		;;
-	esac && {
-		test ! -f "$state_dir"/verbose ||
-			git diff-tree --stat $orig_head..HEAD
-	} &&
-	{
-		test -s "$rewritten_list" &&
-		git notes copy --for-rewrite=rebase < "$rewritten_list" ||
-		true # we don't care if this copying failed
-	} &&
-	hook="$(git rev-parse --git-path hooks/post-rewrite)"
-	if test -x "$hook" && test -s "$rewritten_list"; then
-		"$hook" rebase < "$rewritten_list"
-		true # we don't care if this hook failed
-	fi &&
-		warn "$(eval_gettext "Successfully rebased and updated \$head_name.")"
-
-	return 1 # not failure; just to break the do_rest loop
-}
-
-# can only return 0, when the infinite loop breaks
-do_rest () {
-	while :
-	do
-		do_next || break
-	done
-}
-
-expand_todo_ids() {
-	git rebase--interactive --expand-ids
-}
-
-collapse_todo_ids() {
-	git rebase--interactive --shorten-ids
-}
-
-# Switch to the branch in $into and notify it in the reflog
-checkout_onto () {
-	GIT_REFLOG_ACTION="$GIT_REFLOG_ACTION: checkout $onto_name"
-	output git checkout $onto || die_abort "$(gettext "could not detach HEAD")"
-	git update-ref ORIG_HEAD $orig_head
-}
-
-get_missing_commit_check_level () {
-	check_level=$(git config --get rebase.missingCommitsCheck)
-	check_level=${check_level:-ignore}
-	# Don't be case sensitive
-	printf '%s' "$check_level" | tr 'A-Z' 'a-z'
-}
-
-# Initiate an action. If the cannot be any
-# further action it  may exec a command
-# or exit and not return.
-#
-# TODO: Consider a cleaner return model so it
-# never exits and always return 0 if process
-# is complete.
-#
-# Parameter 1 is the action to initiate.
-#
-# Returns 0 if the action was able to complete
-# and if 1 if further processing is required.
-initiate_action () {
-	case "$1" in
-	continue)
-		# do we have anything to commit?
-		if git diff-index --cached --quiet HEAD --
-		then
-			# Nothing to commit -- skip this commit
-
-			test ! -f "$GIT_DIR"/CHERRY_PICK_HEAD ||
-			rm "$GIT_DIR"/CHERRY_PICK_HEAD ||
-			die "$(gettext "Could not remove CHERRY_PICK_HEAD")"
-		else
-			if ! test -f "$author_script"
-			then
-				gpg_sign_opt_quoted=${gpg_sign_opt:+$(git rev-parse --sq-quote "$gpg_sign_opt")}
-				die "$(eval_gettext "\
-You have staged changes in your working tree.
-If these changes are meant to be
-squashed into the previous commit, run:
-
-  git commit --amend \$gpg_sign_opt_quoted
-
-If they are meant to go into a new commit, run:
-
-  git commit \$gpg_sign_opt_quoted
-
-In both cases, once you're done, continue with:
-
-  git rebase --continue
-")"
-			fi
-			. "$author_script" ||
-				die "$(gettext "Error trying to find the author identity to amend commit")"
-			if test -f "$amend"
-			then
-				current_head=$(git rev-parse --verify HEAD)
-				test "$current_head" = $(cat "$amend") ||
-				die "$(gettext "\
-You have uncommitted changes in your working tree. Please commit them
-first and then run 'git rebase --continue' again.")"
-				do_with_author git commit --amend --no-verify -F "$msg" -e \
-					${gpg_sign_opt:+"$gpg_sign_opt"} $allow_empty_message ||
-					die "$(gettext "Could not commit staged changes.")"
-			else
-				do_with_author git commit --no-verify -F "$msg" -e \
-					${gpg_sign_opt:+"$gpg_sign_opt"} $allow_empty_message ||
-					die "$(gettext "Could not commit staged changes.")"
-			fi
-		fi
-
-		if test -r "$state_dir"/stopped-sha
-		then
-			record_in_rewritten "$(cat "$state_dir"/stopped-sha)"
-		fi
-
-		require_clean_work_tree "rebase"
-		do_rest
-		return 0
-		;;
-	skip)
-		git rerere clear
-		do_rest
-		return 0
-		;;
-	edit-todo)
-		git stripspace --strip-comments <"$todo" >"$todo".new
-		mv -f "$todo".new "$todo"
-		collapse_todo_ids
-		append_todo_help
-		gettext "
-You are editing the todo file of an ongoing interactive rebase.
-To continue rebase after editing, run:
-    git rebase --continue
-
-" | git stripspace --comment-lines >>"$todo"
-
-		git_sequence_editor "$todo" ||
-			die "$(gettext "Could not execute editor")"
-		expand_todo_ids
-
-		exit
-		;;
-	show-current-patch)
-		exec git show REBASE_HEAD --
-		;;
-	*)
-		return 1 # continue
-		;;
-	esac
-}
-
-setup_reflog_action () {
-	comment_for_reflog start
-
-	if test ! -z "$switch_to"
-	then
-		GIT_REFLOG_ACTION="$GIT_REFLOG_ACTION: checkout $switch_to"
-		output git checkout "$switch_to" -- ||
-			die "$(eval_gettext "Could not checkout \$switch_to")"
-
-		comment_for_reflog start
-	fi
-}
-
-init_basic_state () {
-	orig_head=$(git rev-parse --verify HEAD) || die "$(gettext "No HEAD?")"
-	mkdir -p "$state_dir" || die "$(eval_gettext "Could not create temporary \$state_dir")"
-	rm -f "$(git rev-parse --git-path REBASE_HEAD)"
-
-	: > "$state_dir"/interactive || die "$(gettext "Could not mark as interactive")"
-	write_basic_state
-}
-
-init_revisions_and_shortrevisions () {
-	shorthead=$(git rev-parse --short $orig_head)
-	shortonto=$(git rev-parse --short $onto)
-	if test -z "$rebase_root"
-		# this is now equivalent to ! -z "$upstream"
-	then
-		shortupstream=$(git rev-parse --short $upstream)
-		revisions=$upstream...$orig_head
-		shortrevisions=$shortupstream..$shorthead
-	else
-		revisions=$onto...$orig_head
-		shortrevisions=$shorthead
-		test -z "$squash_onto" ||
-		echo "$squash_onto" >"$state_dir"/squash-onto
-	fi
-}
-
-complete_action() {
-	test -s "$todo" || echo noop >> "$todo"
-	test -z "$autosquash" || git rebase--interactive --rearrange-squash || exit
-	test -n "$cmd" && git rebase--interactive --add-exec-commands --cmd "$cmd"
-
-	todocount=$(git stripspace --strip-comments <"$todo" | wc -l)
-	todocount=${todocount##* }
-
-cat >>"$todo" <<EOF
-
-$comment_char $(eval_ngettext \
-	"Rebase \$shortrevisions onto \$shortonto (\$todocount command)" \
-	"Rebase \$shortrevisions onto \$shortonto (\$todocount commands)" \
-	"$todocount")
-EOF
-	append_todo_help
-	gettext "
-However, if you remove everything, the rebase will be aborted.
-
-" | git stripspace --comment-lines >>"$todo"
-
-	if test -z "$keep_empty"
-	then
-		printf '%s\n' "$comment_char $(gettext "Note that empty commits are commented out")" >>"$todo"
-	fi
-
-
-	has_action "$todo" ||
-		return 2
-
-	cp "$todo" "$todo".backup
-	collapse_todo_ids
-	git_sequence_editor "$todo" ||
-		die_abort "$(gettext "Could not execute editor")"
-
-	has_action "$todo" ||
-		return 2
-
-	git rebase--interactive --check-todo-list || {
-		ret=$?
-		checkout_onto
-		exit $ret
-	}
-
-	expand_todo_ids
-	checkout_onto
-	do_rest
-}
-
-git_rebase__preserve_merges () {
-	initiate_action "$action"
-	ret=$?
-	if test $ret = 0; then
-		return 0
-	fi
-
-	setup_reflog_action
-	init_basic_state
-
-	if test -z "$rebase_root"
-	then
-		mkdir "$rewritten" &&
-		for c in $(git merge-base --all $orig_head $upstream)
-		do
-			echo $onto > "$rewritten"/$c ||
-				die "$(gettext "Could not init rewritten commits")"
-		done
-	else
-		mkdir "$rewritten" &&
-		echo $onto > "$rewritten"/root ||
-			die "$(gettext "Could not init rewritten commits")"
-	fi
-
-	init_revisions_and_shortrevisions
-
-	format=$(git config --get rebase.instructionFormat)
-	# the 'rev-list .. | sed' requires %m to parse; the instruction requires %H to parse
-	git rev-list --format="%m%H ${format:-%s}" \
-		--reverse --left-right --topo-order \
-		$revisions ${restrict_revision+^$restrict_revision} | \
-		sed -n "s/^>//p" |
-	while read -r sha1 rest
-	do
-		if test -z "$keep_empty" && is_empty_commit $sha1 && ! is_merge_commit $sha1
-		then
-			comment_out="$comment_char "
-		else
-			comment_out=
-		fi
-
-		if test -z "$rebase_root"
-		then
-			preserve=t
-			for p in $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)
-			do
-				if test -f "$rewritten"/$p
-				then
-					preserve=f
-				fi
-			done
-		else
-			preserve=f
-		fi
-		if test f = "$preserve"
-		then
-			touch "$rewritten"/$sha1
-			printf '%s\n' "${comment_out}pick $sha1 $rest" >>"$todo"
-		fi
-	done
-
-	# Watch for commits that been dropped by --cherry-pick
-	mkdir "$dropped"
-	# Save all non-cherry-picked changes
-	git rev-list $revisions --left-right --cherry-pick | \
-		sed -n "s/^>//p" > "$state_dir"/not-cherry-picks
-	# Now all commits and note which ones are missing in
-	# not-cherry-picks and hence being dropped
-	git rev-list $revisions |
-	while read rev
-	do
-		if test -f "$rewritten"/$rev &&
-		   ! sane_grep "$rev" "$state_dir"/not-cherry-picks >/dev/null
-		then
-			# Use -f2 because if rev-list is telling us this commit is
-			# not worthwhile, we don't want to track its multiple heads,
-			# just the history of its first-parent for others that will
-			# be rebasing on top of it
-			git rev-list --parents -1 $rev | cut -d' ' -s -f2 > "$dropped"/$rev
-			sha1=$(git rev-list -1 $rev)
-			sane_grep -v "^[a-z][a-z]* $sha1" <"$todo" > "${todo}2" ; mv "${todo}2" "$todo"
-			rm "$rewritten"/$rev
-		fi
-	done
-
-	complete_action
-}
diff --git a/git-sh-i18n.sh b/git-sh-i18n.sh
index e3d9f48..a15c062 100644
--- a/git-sh-i18n.sh
+++ b/git-sh-i18n.sh
@@ -51,12 +51,6 @@
 		)
 	}
 
-	eval_ngettext () {
-		ngettext "$1" "$2" "$3" | (
-			export PATH $(git sh-i18n--envsubst --variables "$2");
-			git sh-i18n--envsubst "$2"
-		)
-	}
 	;;
 *)
 	gettext () {
@@ -70,12 +64,6 @@
 		)
 	}
 
-	eval_ngettext () {
-		(test "$3" = 1 && printf "%s" "$1" || printf "%s" "$2") | (
-			export PATH $(git sh-i18n--envsubst --variables "$2");
-			git sh-i18n--envsubst "$2"
-		)
-	}
 	;;
 esac
 
diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index 10d9764..960982f 100644
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -217,15 +217,9 @@
 	then
 		action=$1
 		case "$action" in
-		rebase)
-			gettextln "Cannot rebase: You have unstaged changes." >&2
-			;;
 		"rewrite branches")
 			gettextln "Cannot rewrite branches: You have unstaged changes." >&2
 			;;
-		"pull with rebase")
-			gettextln "Cannot pull with rebase: You have unstaged changes." >&2
-			;;
 		*)
 			eval_gettextln "Cannot \$action: You have unstaged changes." >&2
 			;;
@@ -238,17 +232,7 @@
 		if test $err = 0
 		then
 			action=$1
-			case "$action" in
-			rebase)
-				gettextln "Cannot rebase: Your index contains uncommitted changes." >&2
-				;;
-			"pull with rebase")
-				gettextln "Cannot pull with rebase: Your index contains uncommitted changes." >&2
-				;;
-			*)
-				eval_gettextln "Cannot \$action: Your index contains uncommitted changes." >&2
-				;;
-			esac
+			eval_gettextln "Cannot \$action: Your index contains uncommitted changes." >&2
 		else
 		    gettextln "Additionally, your index contains uncommitted changes." >&2
 		fi
diff --git a/git-submodule.sh b/git-submodule.sh
index dbd2ec2..652861a 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -63,11 +63,6 @@
 	n=$(($1 + 0)) 2>/dev/null && test "$n" = "$1"
 }
 
-# Given a full hex object ID, is this the zero OID?
-is_zero_oid () {
-	echo "$1" | sane_egrep '^0+$' >/dev/null 2>&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.
@@ -145,130 +140,12 @@
 		shift
 	done
 
-	if ! git submodule--helper config --check-writeable >/dev/null 2>&1
+	if test -z "$1"
 	then
-		 die "fatal: $(eval_gettext "please make sure that the .gitmodules file is in the working tree")"
-	fi
-
-	if test -n "$reference_path"
-	then
-		is_absolute_path "$reference_path" ||
-		reference_path="$wt_prefix$reference_path"
-
-		reference="--reference=$reference_path"
-	fi
-
-	repo=$1
-	sm_path=$2
-
-	if test -z "$sm_path"; then
-		sm_path=$(printf '%s\n' "$repo" |
-			sed -e 's|/$||' -e 's|:*/*\.git$||' -e 's|.*[/:]||g')
-	fi
-
-	if test -z "$repo" || test -z "$sm_path"; then
 		usage
 	fi
 
-	is_absolute_path "$sm_path" || sm_path="$wt_prefix$sm_path"
-
-	# assure repo is absolute or relative to parent
-	case "$repo" in
-	./*|../*)
-		test -z "$wt_prefix" ||
-		die "fatal: $(gettext "Relative path can only be used from the toplevel of the working tree")"
-
-		# dereference source url relative to parent's url
-		realrepo=$(git submodule--helper resolve-relative-url "$repo") || exit
-		;;
-	*:*|/*)
-		# absolute url
-		realrepo=$repo
-		;;
-	*)
-		die "fatal: $(eval_gettext "repo URL: '\$repo' must be absolute or begin with ./|../")"
-	;;
-	esac
-
-	# normalize path:
-	# multiple //; leading ./; /./; /../; trailing /
-	sm_path=$(printf '%s/\n' "$sm_path" |
-		sed -e '
-			s|//*|/|g
-			s|^\(\./\)*||
-			s|/\(\./\)*|/|g
-			:start
-			s|\([^/]*\)/\.\./||
-			tstart
-			s|/*$||
-		')
-	if test -z "$force"
-	then
-		git ls-files --error-unmatch "$sm_path" > /dev/null 2>&1 &&
-		die "fatal: $(eval_gettext "'\$sm_path' already exists in the index")"
-	else
-		git ls-files -s "$sm_path" | sane_grep -v "^160000" > /dev/null 2>&1 &&
-		die "fatal: $(eval_gettext "'\$sm_path' already exists in the index and is not a submodule")"
-	fi
-
-	if test -d "$sm_path" &&
-		test -z $(git -C "$sm_path" rev-parse --show-cdup 2>/dev/null)
-	then
-	    git -C "$sm_path" rev-parse --verify -q HEAD >/dev/null ||
-	    die "fatal: $(eval_gettext "'\$sm_path' does not have a commit checked out")"
-	fi
-
-	if test -z "$force"
-	then
-	    dryerr=$(git add --dry-run --ignore-missing --no-warn-embedded-repo "$sm_path" 2>&1 >/dev/null)
-	    res=$?
-	    if test $res -ne 0
-	    then
-		 echo >&2 "$dryerr"
-		 exit $res
-	    fi
-	fi
-
-	if test -n "$custom_name"
-	then
-		sm_name="$custom_name"
-	else
-		sm_name="$sm_path"
-	fi
-
-	if ! git submodule--helper check-name "$sm_name"
-	then
-		die "fatal: $(eval_gettext "'$sm_name' is not a valid submodule name")"
-	fi
-
-	git submodule--helper add-clone ${GIT_QUIET:+--quiet} ${force:+"--force"} ${progress:+"--progress"} ${branch:+--branch "$branch"} --prefix "$wt_prefix" --path "$sm_path" --name "$sm_name" --url "$realrepo" ${reference:+"$reference"} ${dissociate:+"--dissociate"} ${depth:+"$depth"} || exit
-	git config submodule."$sm_name".url "$realrepo"
-
-	git add --no-warn-embedded-repo $force "$sm_path" ||
-	die "fatal: $(eval_gettext "Failed to add submodule '\$sm_path'")"
-
-	git submodule--helper config submodule."$sm_name".path "$sm_path" &&
-	git submodule--helper config submodule."$sm_name".url "$repo" &&
-	if test -n "$branch"
-	then
-		git submodule--helper config submodule."$sm_name".branch "$branch"
-	fi &&
-	git add --force .gitmodules ||
-	die "fatal: $(eval_gettext "Failed to register submodule '\$sm_path'")"
-
-	# NEEDSWORK: In a multi-working-tree world, this needs to be
-	# set in the per-worktree config.
-	if git config --get submodule.active >/dev/null
-	then
-		# If the submodule being adding isn't already covered by the
-		# current configured pathspec, set the submodule's active flag
-		if ! git submodule--helper is-active "$sm_path"
-		then
-			git config submodule."$sm_name".active "true"
-		fi
-	else
-		git config submodule."$sm_name".active "true"
-	fi
+	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"} -- "$@"
 }
 
 #
@@ -369,13 +246,6 @@
 	git ${wt_prefix:+-C "$wt_prefix"} submodule--helper deinit ${GIT_QUIET:+--quiet} ${force:+--force} ${deinit_all:+--all} -- "$@"
 }
 
-is_tip_reachable () (
-	sanitize_submodule_env &&
-	cd "$1" &&
-	rev=$(git rev-list -n 1 "$2" --not --all 2>/dev/null) &&
-	test -z "$rev"
-)
-
 # usage: fetch_in_submodule <module_path> [<depth>] [<sha1>]
 # Because arguments are positional, use an empty string to omit <depth>
 # but include <sha1>.
@@ -519,14 +389,13 @@
 
 		git submodule--helper ensure-core-worktree "$sm_path" || exit 1
 
-		update_module=$(git submodule--helper update-module-mode $just_cloned "$sm_path" $update)
-
 		displaypath=$(git submodule--helper relative-path "$prefix$sm_path" "$wt_prefix")
 
 		if test $just_cloned -eq 1
 		then
 			subsha1=
 		else
+			just_cloned=
 			subsha1=$(sanitize_submodule_env; cd "$sm_path" &&
 				git rev-parse --verify HEAD) ||
 			die "fatal: $(eval_gettext "Unable to find current revision in submodule path '\$displaypath'")"
@@ -547,70 +416,38 @@
 			die "fatal: $(eval_gettext "Unable to find current \${remote_name}/\${branch} revision in submodule path '\$sm_path'")"
 		fi
 
-		if test "$subsha1" != "$sha1" || test -n "$force"
-		then
-			subforce=$force
-			# If we don't already have a -f flag and the submodule has never been checked out
-			if test -z "$subsha1" && test -z "$force"
-			then
-				subforce="-f"
-			fi
+		out=$(git submodule--helper run-update-procedure \
+			  ${wt_prefix:+--prefix "$wt_prefix"} \
+			  ${GIT_QUIET:+--quiet} \
+			  ${force:+--force} \
+			  ${just_cloned:+--just-cloned} \
+			  ${nofetch:+--no-fetch} \
+			  ${depth:+"$depth"} \
+			  ${update:+--update "$update"} \
+			  ${prefix:+--recursive-prefix "$prefix"} \
+			  ${sha1:+--oid "$sha1"} \
+			  ${subsha1:+--suboid "$subsha1"} \
+			  "--" \
+			  "$sm_path")
 
-			if test -z "$nofetch"
-			then
-				# Run fetch only if $sha1 isn't present or it
-				# is not reachable from a ref.
-				is_tip_reachable "$sm_path" "$sha1" ||
-				fetch_in_submodule "$sm_path" $depth ||
-				say "$(eval_gettext "Unable to fetch in submodule path '\$displaypath'; trying to directly fetch \$sha1:")"
-
-				# Now we tried the usual fetch, but $sha1 may
-				# not be reachable from any of the refs
-				is_tip_reachable "$sm_path" "$sha1" ||
-				fetch_in_submodule "$sm_path" "$depth" "$sha1" ||
-				die "fatal: $(eval_gettext "Fetched in submodule path '\$displaypath', but it did not contain \$sha1. Direct fetching of that commit failed.")"
-			fi
-
-			must_die_on_failure=
-			case "$update_module" in
-			checkout)
-				command="git checkout $subforce -q"
-				die_msg="fatal: $(eval_gettext "Unable to checkout '\$sha1' in submodule path '\$displaypath'")"
-				say_msg="$(eval_gettext "Submodule path '\$displaypath': checked out '\$sha1'")"
-				;;
-			rebase)
-				command="git rebase ${GIT_QUIET:+--quiet}"
-				die_msg="fatal: $(eval_gettext "Unable to rebase '\$sha1' in submodule path '\$displaypath'")"
-				say_msg="$(eval_gettext "Submodule path '\$displaypath': rebased into '\$sha1'")"
-				must_die_on_failure=yes
-				;;
-			merge)
-				command="git merge ${GIT_QUIET:+--quiet}"
-				die_msg="fatal: $(eval_gettext "Unable to merge '\$sha1' in submodule path '\$displaypath'")"
-				say_msg="$(eval_gettext "Submodule path '\$displaypath': merged in '\$sha1'")"
-				must_die_on_failure=yes
-				;;
-			!*)
-				command="${update_module#!}"
-				die_msg="fatal: $(eval_gettext "Execution of '\$command \$sha1' failed in submodule path '\$displaypath'")"
-				say_msg="$(eval_gettext "Submodule path '\$displaypath': '\$command \$sha1'")"
-				must_die_on_failure=yes
-				;;
-			*)
-				die "fatal: $(eval_gettext "Invalid update mode '$update_module' for submodule path '$path'")"
-			esac
-
-			if (sanitize_submodule_env; cd "$sm_path" && $command "$sha1")
-			then
-				say "$say_msg"
-			elif test -n "$must_die_on_failure"
-			then
-				die_with_status 2 "$die_msg"
-			else
-				err="${err};$die_msg"
-				continue
-			fi
-		fi
+		# exit codes for run-update-procedure:
+		# 0: update was successful, say command output
+		# 1: update procedure failed, but should not die
+		# 2 or 128: subcommand died during execution
+		# 3: no update procedure was run
+		res="$?"
+		case $res in
+		0)
+			say "$out"
+			;;
+		1)
+			err="${err};fatal: $out"
+			continue
+			;;
+		2|128)
+			die_with_status $res "fatal: $out"
+			;;
+		esac
 
 		if test -n "$recursive"
 		then
diff --git a/git-svn.perl b/git-svn.perl
index 70cb5e2..be987e3 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -273,7 +273,6 @@
 			  'fetch-all|all' => \$_fetch_all,
 			  'dry-run|n' => \$_dry_run,
 			  'rebase-merges|p' => \$_rebase_merges,
-			  'preserve-merges|p' => \$_rebase_merges,
 			  %fc_opts } ],
 	'commit-diff' => [ \&cmd_commit_diff,
 	                   'Commit a diff between two trees',
diff --git a/git.c b/git.c
index 18bed9a..5ff21be 100644
--- a/git.c
+++ b/git.c
@@ -561,7 +561,7 @@
 	{ "merge-tree", cmd_merge_tree, RUN_SETUP | NO_PARSEOPT },
 	{ "mktag", cmd_mktag, RUN_SETUP | NO_PARSEOPT },
 	{ "mktree", cmd_mktree, RUN_SETUP },
-	{ "multi-pack-index", cmd_multi_pack_index, RUN_SETUP_GENTLY },
+	{ "multi-pack-index", cmd_multi_pack_index, RUN_SETUP },
 	{ "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 	{ "name-rev", cmd_name_rev, RUN_SETUP },
 	{ "notes", cmd_notes, RUN_SETUP },
@@ -577,7 +577,6 @@
 	{ "range-diff", cmd_range_diff, RUN_SETUP | USE_PAGER },
 	{ "read-tree", cmd_read_tree, RUN_SETUP | SUPPORT_SUPER_PREFIX},
 	{ "rebase", cmd_rebase, RUN_SETUP | NEED_WORK_TREE },
-	{ "rebase--interactive", cmd_rebase__interactive, RUN_SETUP | NEED_WORK_TREE },
 	{ "receive-pack", cmd_receive_pack },
 	{ "reflog", cmd_reflog, RUN_SETUP },
 	{ "remote", cmd_remote, RUN_SETUP },
diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index e09e024..fbd1c20 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -3796,7 +3796,8 @@
 	my @headslist;
 
 	open my $fd, '-|', git_cmd(), 'for-each-ref',
-		($limit ? '--count='.($limit+1) : ()), '--sort=-committerdate',
+		($limit ? '--count='.($limit+1) : ()),
+		'--sort=-HEAD', '--sort=-committerdate',
 		'--format=%(objectname) %(refname) %(subject)%00%(committer)',
 		@patterns
 		or return;
diff --git a/gpg-interface.c b/gpg-interface.c
index 127aecf..800d8ca 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -3,11 +3,14 @@
 #include "config.h"
 #include "run-command.h"
 #include "strbuf.h"
+#include "dir.h"
 #include "gpg-interface.h"
 #include "sigchain.h"
 #include "tempfile.h"
+#include "alias.h"
 
 static char *configured_signing_key;
+static const char *ssh_default_key_command, *ssh_allowed_signers, *ssh_revocation_file;
 static enum signature_trust_level configured_min_trust_level = TRUST_UNDEFINED;
 
 struct gpg_format {
@@ -15,6 +18,14 @@
 	const char *program;
 	const char **verify_args;
 	const char **sigs;
+	int (*verify_signed_buffer)(struct signature_check *sigc,
+				    struct gpg_format *fmt, const char *payload,
+				    size_t payload_size, const char *signature,
+				    size_t signature_size);
+	int (*sign_buffer)(struct strbuf *buffer, struct strbuf *signature,
+			   const char *signing_key);
+	const char *(*get_default_key)(void);
+	const char *(*get_key_id)(void);
 };
 
 static const char *openpgp_verify_args[] = {
@@ -35,14 +46,59 @@
 	NULL
 };
 
+static const char *ssh_verify_args[] = { NULL };
+static const char *ssh_sigs[] = {
+	"-----BEGIN SSH SIGNATURE-----",
+	NULL
+};
+
+static int verify_gpg_signed_buffer(struct signature_check *sigc,
+				    struct gpg_format *fmt, const char *payload,
+				    size_t payload_size, const char *signature,
+				    size_t signature_size);
+static int verify_ssh_signed_buffer(struct signature_check *sigc,
+				    struct gpg_format *fmt, const char *payload,
+				    size_t payload_size, const char *signature,
+				    size_t signature_size);
+static int sign_buffer_gpg(struct strbuf *buffer, struct strbuf *signature,
+			   const char *signing_key);
+static int sign_buffer_ssh(struct strbuf *buffer, struct strbuf *signature,
+			   const char *signing_key);
+
+static const char *get_default_ssh_signing_key(void);
+
+static const char *get_ssh_key_id(void);
+
 static struct gpg_format gpg_format[] = {
-	{ .name = "openpgp", .program = "gpg",
-	  .verify_args = openpgp_verify_args,
-	  .sigs = openpgp_sigs
+	{
+		.name = "openpgp",
+		.program = "gpg",
+		.verify_args = openpgp_verify_args,
+		.sigs = openpgp_sigs,
+		.verify_signed_buffer = verify_gpg_signed_buffer,
+		.sign_buffer = sign_buffer_gpg,
+		.get_default_key = NULL,
+		.get_key_id = NULL,
 	},
-	{ .name = "x509", .program = "gpgsm",
-	  .verify_args = x509_verify_args,
-	  .sigs = x509_sigs
+	{
+		.name = "x509",
+		.program = "gpgsm",
+		.verify_args = x509_verify_args,
+		.sigs = x509_sigs,
+		.verify_signed_buffer = verify_gpg_signed_buffer,
+		.sign_buffer = sign_buffer_gpg,
+		.get_default_key = NULL,
+		.get_key_id = NULL,
+	},
+	{
+		.name = "ssh",
+		.program = "ssh-keygen",
+		.verify_args = ssh_verify_args,
+		.sigs = ssh_sigs,
+		.verify_signed_buffer = verify_ssh_signed_buffer,
+		.sign_buffer = sign_buffer_ssh,
+		.get_default_key = get_default_ssh_signing_key,
+		.get_key_id = get_ssh_key_id,
 	},
 };
 
@@ -72,7 +128,7 @@
 void signature_check_clear(struct signature_check *sigc)
 {
 	FREE_AND_NULL(sigc->payload);
-	FREE_AND_NULL(sigc->gpg_output);
+	FREE_AND_NULL(sigc->output);
 	FREE_AND_NULL(sigc->gpg_status);
 	FREE_AND_NULL(sigc->signer);
 	FREE_AND_NULL(sigc->key);
@@ -257,16 +313,16 @@
 	FREE_AND_NULL(sigc->key);
 }
 
-static int verify_signed_buffer(const char *payload, size_t payload_size,
-				const char *signature, size_t signature_size,
-				struct strbuf *gpg_output,
-				struct strbuf *gpg_status)
+static int verify_gpg_signed_buffer(struct signature_check *sigc,
+				    struct gpg_format *fmt, const char *payload,
+				    size_t payload_size, const char *signature,
+				    size_t signature_size)
 {
 	struct child_process gpg = CHILD_PROCESS_INIT;
-	struct gpg_format *fmt;
 	struct tempfile *temp;
 	int ret;
-	struct strbuf buf = STRBUF_INIT;
+	struct strbuf gpg_stdout = STRBUF_INIT;
+	struct strbuf gpg_stderr = STRBUF_INIT;
 
 	temp = mks_tempfile_t(".git_vtag_tmpXXXXXX");
 	if (!temp)
@@ -279,10 +335,6 @@
 		return -1;
 	}
 
-	fmt = get_format_by_sig(signature);
-	if (!fmt)
-		BUG("bad signature '%s'", signature);
-
 	strvec_push(&gpg.args, fmt->program);
 	strvec_pushv(&gpg.args, fmt->verify_args);
 	strvec_pushl(&gpg.args,
@@ -290,18 +342,220 @@
 		     "--verify", temp->filename.buf, "-",
 		     NULL);
 
-	if (!gpg_status)
-		gpg_status = &buf;
-
 	sigchain_push(SIGPIPE, SIG_IGN);
-	ret = pipe_command(&gpg, payload, payload_size,
-			   gpg_status, 0, gpg_output, 0);
+	ret = pipe_command(&gpg, payload, payload_size, &gpg_stdout, 0,
+			   &gpg_stderr, 0);
 	sigchain_pop(SIGPIPE);
 
 	delete_tempfile(&temp);
 
-	ret |= !strstr(gpg_status->buf, "\n[GNUPG:] GOODSIG ");
-	strbuf_release(&buf); /* no matter it was used or not */
+	ret |= !strstr(gpg_stdout.buf, "\n[GNUPG:] GOODSIG ");
+	sigc->payload = xmemdupz(payload, payload_size);
+	sigc->output = strbuf_detach(&gpg_stderr, NULL);
+	sigc->gpg_status = strbuf_detach(&gpg_stdout, NULL);
+
+	parse_gpg_output(sigc);
+
+	strbuf_release(&gpg_stdout);
+	strbuf_release(&gpg_stderr);
+
+	return ret;
+}
+
+static void parse_ssh_output(struct signature_check *sigc)
+{
+	const char *line, *principal, *search;
+	char *to_free;
+	char *key = NULL;
+
+	/*
+	 * ssh-keygen output should be:
+	 * Good "git" signature for PRINCIPAL with RSA key SHA256:FINGERPRINT
+	 *
+	 * or for valid but unknown keys:
+	 * Good "git" signature with RSA key SHA256:FINGERPRINT
+	 *
+	 * Note that "PRINCIPAL" can contain whitespace, "RSA" and
+	 * "SHA256" part could be a different token that names of
+	 * the algorithms used, and "FINGERPRINT" is a hexadecimal
+	 * string.  By finding the last occurence of " with ", we can
+	 * reliably parse out the PRINCIPAL.
+	 */
+	sigc->result = 'B';
+	sigc->trust_level = TRUST_NEVER;
+
+	line = to_free = xmemdupz(sigc->output, strcspn(sigc->output, "\n"));
+
+	if (skip_prefix(line, "Good \"git\" signature for ", &line)) {
+		/* Valid signature and known principal */
+		sigc->result = 'G';
+		sigc->trust_level = TRUST_FULLY;
+
+		/* Search for the last "with" to get the full principal */
+		principal = line;
+		do {
+			search = strstr(line, " with ");
+			if (search)
+				line = search + 1;
+		} while (search != NULL);
+		sigc->signer = xmemdupz(principal, line - principal - 1);
+	} else if (skip_prefix(line, "Good \"git\" signature with ", &line)) {
+		/* Valid signature, but key unknown */
+		sigc->result = 'G';
+		sigc->trust_level = TRUST_UNDEFINED;
+	} else {
+		goto cleanup;
+	}
+
+	key = strstr(line, "key");
+	if (key) {
+		sigc->fingerprint = xstrdup(strstr(line, "key") + 4);
+		sigc->key = xstrdup(sigc->fingerprint);
+	} else {
+		/*
+		 * Output did not match what we expected
+		 * Treat the signature as bad
+		 */
+		sigc->result = 'B';
+	}
+
+cleanup:
+	free(to_free);
+}
+
+static int verify_ssh_signed_buffer(struct signature_check *sigc,
+				    struct gpg_format *fmt, const char *payload,
+				    size_t payload_size, const char *signature,
+				    size_t signature_size)
+{
+	struct child_process ssh_keygen = CHILD_PROCESS_INIT;
+	struct tempfile *buffer_file;
+	int ret = -1;
+	const char *line;
+	size_t trust_size;
+	char *principal;
+	struct strbuf ssh_principals_out = STRBUF_INIT;
+	struct strbuf ssh_principals_err = STRBUF_INIT;
+	struct strbuf ssh_keygen_out = STRBUF_INIT;
+	struct strbuf ssh_keygen_err = STRBUF_INIT;
+
+	if (!ssh_allowed_signers) {
+		error(_("gpg.ssh.allowedSignersFile needs to be configured and exist for ssh signature verification"));
+		return -1;
+	}
+
+	buffer_file = mks_tempfile_t(".git_vtag_tmpXXXXXX");
+	if (!buffer_file)
+		return error_errno(_("could not create temporary file"));
+	if (write_in_full(buffer_file->fd, signature, signature_size) < 0 ||
+	    close_tempfile_gently(buffer_file) < 0) {
+		error_errno(_("failed writing detached signature to '%s'"),
+			    buffer_file->filename.buf);
+		delete_tempfile(&buffer_file);
+		return -1;
+	}
+
+	/* Find the principal from the signers */
+	strvec_pushl(&ssh_keygen.args, fmt->program,
+		     "-Y", "find-principals",
+		     "-f", ssh_allowed_signers,
+		     "-s", buffer_file->filename.buf,
+		     NULL);
+	ret = pipe_command(&ssh_keygen, NULL, 0, &ssh_principals_out, 0,
+			   &ssh_principals_err, 0);
+	if (ret && strstr(ssh_principals_err.buf, "usage:")) {
+		error(_("ssh-keygen -Y find-principals/verify is needed for ssh signature verification (available in openssh version 8.2p1+)"));
+		goto out;
+	}
+	if (ret || !ssh_principals_out.len) {
+		/*
+		 * We did not find a matching principal in the allowedSigners
+		 * Check without validation
+		 */
+		child_process_init(&ssh_keygen);
+		strvec_pushl(&ssh_keygen.args, fmt->program,
+			     "-Y", "check-novalidate",
+			     "-n", "git",
+			     "-s", buffer_file->filename.buf,
+			     NULL);
+		pipe_command(&ssh_keygen, payload, payload_size,
+				   &ssh_keygen_out, 0, &ssh_keygen_err, 0);
+
+		/*
+		 * Fail on unknown keys
+		 * we still call check-novalidate to display the signature info
+		 */
+		ret = -1;
+	} else {
+		/* Check every principal we found (one per line) */
+		for (line = ssh_principals_out.buf; *line;
+		     line = strchrnul(line + 1, '\n')) {
+			while (*line == '\n')
+				line++;
+			if (!*line)
+				break;
+
+			trust_size = strcspn(line, "\n");
+			principal = xmemdupz(line, trust_size);
+
+			child_process_init(&ssh_keygen);
+			strbuf_release(&ssh_keygen_out);
+			strbuf_release(&ssh_keygen_err);
+			strvec_push(&ssh_keygen.args, fmt->program);
+			/*
+			 * We found principals
+			 * Try with each until we find a match
+			 */
+			strvec_pushl(&ssh_keygen.args, "-Y", "verify",
+				     "-n", "git",
+				     "-f", ssh_allowed_signers,
+				     "-I", principal,
+				     "-s", buffer_file->filename.buf,
+				     NULL);
+
+			if (ssh_revocation_file) {
+				if (file_exists(ssh_revocation_file)) {
+					strvec_pushl(&ssh_keygen.args, "-r",
+						     ssh_revocation_file, NULL);
+				} else {
+					warning(_("ssh signing revocation file configured but not found: %s"),
+						ssh_revocation_file);
+				}
+			}
+
+			sigchain_push(SIGPIPE, SIG_IGN);
+			ret = pipe_command(&ssh_keygen, payload, payload_size,
+					   &ssh_keygen_out, 0, &ssh_keygen_err, 0);
+			sigchain_pop(SIGPIPE);
+
+			FREE_AND_NULL(principal);
+
+			if (!ret)
+				ret = !starts_with(ssh_keygen_out.buf, "Good");
+
+			if (!ret)
+				break;
+		}
+	}
+
+	sigc->payload = xmemdupz(payload, payload_size);
+	strbuf_stripspace(&ssh_keygen_out, 0);
+	strbuf_stripspace(&ssh_keygen_err, 0);
+	/* Add stderr outputs to show the user actual ssh-keygen errors */
+	strbuf_add(&ssh_keygen_out, ssh_principals_err.buf, ssh_principals_err.len);
+	strbuf_add(&ssh_keygen_out, ssh_keygen_err.buf, ssh_keygen_err.len);
+	sigc->output = strbuf_detach(&ssh_keygen_out, NULL);
+	sigc->gpg_status = xstrdup(sigc->output);
+
+	parse_ssh_output(sigc);
+
+out:
+	if (buffer_file)
+		delete_tempfile(&buffer_file);
+	strbuf_release(&ssh_principals_out);
+	strbuf_release(&ssh_principals_err);
+	strbuf_release(&ssh_keygen_out);
+	strbuf_release(&ssh_keygen_err);
 
 	return ret;
 }
@@ -309,35 +563,32 @@
 int check_signature(const char *payload, size_t plen, const char *signature,
 	size_t slen, struct signature_check *sigc)
 {
-	struct strbuf gpg_output = STRBUF_INIT;
-	struct strbuf gpg_status = STRBUF_INIT;
+	struct gpg_format *fmt;
 	int status;
 
 	sigc->result = 'N';
 	sigc->trust_level = -1;
 
-	status = verify_signed_buffer(payload, plen, signature, slen,
-				      &gpg_output, &gpg_status);
-	if (status && !gpg_output.len)
-		goto out;
-	sigc->payload = xmemdupz(payload, plen);
-	sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
-	sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
-	parse_gpg_output(sigc);
+	fmt = get_format_by_sig(signature);
+	if (!fmt)
+		die(_("bad/incompatible signature '%s'"), signature);
+
+	status = fmt->verify_signed_buffer(sigc, fmt, payload, plen, signature,
+					   slen);
+
+	if (status && !sigc->output)
+		return !!status;
+
 	status |= sigc->result != 'G';
 	status |= sigc->trust_level < configured_min_trust_level;
 
- out:
-	strbuf_release(&gpg_status);
-	strbuf_release(&gpg_output);
-
 	return !!status;
 }
 
 void print_signature_buffer(const struct signature_check *sigc, unsigned flags)
 {
-	const char *output = flags & GPG_VERIFY_RAW ?
-		sigc->gpg_status : sigc->gpg_output;
+	const char *output = flags & GPG_VERIFY_RAW ? sigc->gpg_status :
+							    sigc->output;
 
 	if (flags & GPG_VERIFY_VERBOSE && sigc->payload)
 		fputs(sigc->payload, stdout);
@@ -419,12 +670,33 @@
 		return 0;
 	}
 
+	if (!strcmp(var, "gpg.ssh.defaultkeycommand")) {
+		if (!value)
+			return config_error_nonbool(var);
+		return git_config_string(&ssh_default_key_command, var, value);
+	}
+
+	if (!strcmp(var, "gpg.ssh.allowedsignersfile")) {
+		if (!value)
+			return config_error_nonbool(var);
+		return git_config_pathname(&ssh_allowed_signers, var, value);
+	}
+
+	if (!strcmp(var, "gpg.ssh.revocationfile")) {
+		if (!value)
+			return config_error_nonbool(var);
+		return git_config_pathname(&ssh_revocation_file, var, value);
+	}
+
 	if (!strcmp(var, "gpg.program") || !strcmp(var, "gpg.openpgp.program"))
 		fmtname = "openpgp";
 
 	if (!strcmp(var, "gpg.x509.program"))
 		fmtname = "x509";
 
+	if (!strcmp(var, "gpg.ssh.program"))
+		fmtname = "ssh";
+
 	if (fmtname) {
 		fmt = get_format_by_name(fmtname);
 		return git_config_string(&fmt->program, var, value);
@@ -433,18 +705,148 @@
 	return 0;
 }
 
+static char *get_ssh_key_fingerprint(const char *signing_key)
+{
+	struct child_process ssh_keygen = CHILD_PROCESS_INIT;
+	int ret = -1;
+	struct strbuf fingerprint_stdout = STRBUF_INIT;
+	struct strbuf **fingerprint;
+	char *fingerprint_ret;
+
+	/*
+	 * With SSH Signing this can contain a filename or a public key
+	 * For textual representation we usually want a fingerprint
+	 */
+	if (starts_with(signing_key, "ssh-")) {
+		strvec_pushl(&ssh_keygen.args, "ssh-keygen", "-lf", "-", NULL);
+		ret = pipe_command(&ssh_keygen, signing_key,
+				   strlen(signing_key), &fingerprint_stdout, 0,
+				   NULL, 0);
+	} else {
+		strvec_pushl(&ssh_keygen.args, "ssh-keygen", "-lf",
+			     configured_signing_key, NULL);
+		ret = pipe_command(&ssh_keygen, NULL, 0, &fingerprint_stdout, 0,
+				   NULL, 0);
+	}
+
+	if (!!ret)
+		die_errno(_("failed to get the ssh fingerprint for key '%s'"),
+			  signing_key);
+
+	fingerprint = strbuf_split_max(&fingerprint_stdout, ' ', 3);
+	if (!fingerprint[1])
+		die_errno(_("failed to get the ssh fingerprint for key '%s'"),
+			  signing_key);
+
+	fingerprint_ret = strbuf_detach(fingerprint[1], NULL);
+	strbuf_list_free(fingerprint);
+	strbuf_release(&fingerprint_stdout);
+	return fingerprint_ret;
+}
+
+/* Returns the first public key from an ssh-agent to use for signing */
+static const char *get_default_ssh_signing_key(void)
+{
+	struct child_process ssh_default_key = CHILD_PROCESS_INIT;
+	int ret = -1;
+	struct strbuf key_stdout = STRBUF_INIT, key_stderr = STRBUF_INIT;
+	struct strbuf **keys;
+	char *key_command = NULL;
+	const char **argv;
+	int n;
+	char *default_key = NULL;
+
+	if (!ssh_default_key_command)
+		die(_("either user.signingkey or gpg.ssh.defaultKeyCommand needs to be configured"));
+
+	key_command = xstrdup(ssh_default_key_command);
+	n = split_cmdline(key_command, &argv);
+
+	if (n < 0)
+		die("malformed build-time gpg.ssh.defaultKeyCommand: %s",
+		    split_cmdline_strerror(n));
+
+	strvec_pushv(&ssh_default_key.args, argv);
+	ret = pipe_command(&ssh_default_key, NULL, 0, &key_stdout, 0,
+			   &key_stderr, 0);
+
+	if (!ret) {
+		keys = strbuf_split_max(&key_stdout, '\n', 2);
+		if (keys[0] && starts_with(keys[0]->buf, "ssh-")) {
+			default_key = strbuf_detach(keys[0], NULL);
+		} else {
+			warning(_("gpg.ssh.defaultKeycommand succeeded but returned no keys: %s %s"),
+				key_stderr.buf, key_stdout.buf);
+		}
+
+		strbuf_list_free(keys);
+	} else {
+		warning(_("gpg.ssh.defaultKeyCommand failed: %s %s"),
+			key_stderr.buf, key_stdout.buf);
+	}
+
+	free(key_command);
+	free(argv);
+	strbuf_release(&key_stdout);
+
+	return default_key;
+}
+
+static const char *get_ssh_key_id(void) {
+	return get_ssh_key_fingerprint(get_signing_key());
+}
+
+/* Returns a textual but unique representation of the signing key */
+const char *get_signing_key_id(void)
+{
+	if (use_format->get_key_id) {
+		return use_format->get_key_id();
+	}
+
+	/* GPG/GPGSM only store a key id on this variable */
+	return get_signing_key();
+}
+
 const char *get_signing_key(void)
 {
 	if (configured_signing_key)
 		return configured_signing_key;
-	return git_committer_info(IDENT_STRICT|IDENT_NO_DATE);
+	if (use_format->get_default_key) {
+		return use_format->get_default_key();
+	}
+
+	return git_committer_info(IDENT_STRICT | IDENT_NO_DATE);
 }
 
 int sign_buffer(struct strbuf *buffer, struct strbuf *signature, const char *signing_key)
 {
+	return use_format->sign_buffer(buffer, signature, signing_key);
+}
+
+/*
+ * Strip CR from the line endings, in case we are on Windows.
+ * NEEDSWORK: make it trim only CRs before LFs and rename
+ */
+static void remove_cr_after(struct strbuf *buffer, size_t offset)
+{
+	size_t i, j;
+
+	for (i = j = offset; i < buffer->len; i++) {
+		if (buffer->buf[i] != '\r') {
+			if (i != j)
+				buffer->buf[j] = buffer->buf[i];
+			j++;
+		}
+	}
+	strbuf_setlen(buffer, j);
+}
+
+static int sign_buffer_gpg(struct strbuf *buffer, struct strbuf *signature,
+			  const char *signing_key)
+{
 	struct child_process gpg = CHILD_PROCESS_INIT;
 	int ret;
-	size_t i, j, bottom;
+	size_t bottom;
 	struct strbuf gpg_status = STRBUF_INIT;
 
 	strvec_pushl(&gpg.args,
@@ -470,13 +872,98 @@
 		return error(_("gpg failed to sign the data"));
 
 	/* Strip CR from the line endings, in case we are on Windows. */
-	for (i = j = bottom; i < signature->len; i++)
-		if (signature->buf[i] != '\r') {
-			if (i != j)
-				signature->buf[j] = signature->buf[i];
-			j++;
-		}
-	strbuf_setlen(signature, j);
+	remove_cr_after(signature, bottom);
 
 	return 0;
 }
+
+static int sign_buffer_ssh(struct strbuf *buffer, struct strbuf *signature,
+			   const char *signing_key)
+{
+	struct child_process signer = CHILD_PROCESS_INIT;
+	int ret = -1;
+	size_t bottom, keylen;
+	struct strbuf signer_stderr = STRBUF_INIT;
+	struct tempfile *key_file = NULL, *buffer_file = NULL;
+	char *ssh_signing_key_file = NULL;
+	struct strbuf ssh_signature_filename = STRBUF_INIT;
+
+	if (!signing_key || signing_key[0] == '\0')
+		return error(
+			_("user.signingkey needs to be set for ssh signing"));
+
+	if (starts_with(signing_key, "ssh-")) {
+		/* A literal ssh key */
+		key_file = mks_tempfile_t(".git_signing_key_tmpXXXXXX");
+		if (!key_file)
+			return error_errno(
+				_("could not create temporary file"));
+		keylen = strlen(signing_key);
+		if (write_in_full(key_file->fd, signing_key, keylen) < 0 ||
+		    close_tempfile_gently(key_file) < 0) {
+			error_errno(_("failed writing ssh signing key to '%s'"),
+				    key_file->filename.buf);
+			goto out;
+		}
+		ssh_signing_key_file = strbuf_detach(&key_file->filename, NULL);
+	} else {
+		/* We assume a file */
+		ssh_signing_key_file = expand_user_path(signing_key, 1);
+	}
+
+	buffer_file = mks_tempfile_t(".git_signing_buffer_tmpXXXXXX");
+	if (!buffer_file) {
+		error_errno(_("could not create temporary file"));
+		goto out;
+	}
+
+	if (write_in_full(buffer_file->fd, buffer->buf, buffer->len) < 0 ||
+	    close_tempfile_gently(buffer_file) < 0) {
+		error_errno(_("failed writing ssh signing key buffer to '%s'"),
+			    buffer_file->filename.buf);
+		goto out;
+	}
+
+	strvec_pushl(&signer.args, use_format->program,
+		     "-Y", "sign",
+		     "-n", "git",
+		     "-f", ssh_signing_key_file,
+		     buffer_file->filename.buf,
+		     NULL);
+
+	sigchain_push(SIGPIPE, SIG_IGN);
+	ret = pipe_command(&signer, NULL, 0, NULL, 0, &signer_stderr, 0);
+	sigchain_pop(SIGPIPE);
+
+	if (ret) {
+		if (strstr(signer_stderr.buf, "usage:"))
+			error(_("ssh-keygen -Y sign is needed for ssh signing (available in openssh version 8.2p1+)"));
+
+		error("%s", signer_stderr.buf);
+		goto out;
+	}
+
+	bottom = signature->len;
+
+	strbuf_addbuf(&ssh_signature_filename, &buffer_file->filename);
+	strbuf_addstr(&ssh_signature_filename, ".sig");
+	if (strbuf_read_file(signature, ssh_signature_filename.buf, 0) < 0) {
+		error_errno(
+			_("failed reading ssh signing data buffer from '%s'"),
+			ssh_signature_filename.buf);
+	}
+	unlink_or_warn(ssh_signature_filename.buf);
+
+	/* Strip CR from the line endings, in case we are on Windows. */
+	remove_cr_after(signature, bottom);
+
+out:
+	if (key_file)
+		delete_tempfile(&key_file);
+	if (buffer_file)
+		delete_tempfile(&buffer_file);
+	strbuf_release(&signer_stderr);
+	strbuf_release(&ssh_signature_filename);
+	FREE_AND_NULL(ssh_signing_key_file);
+	return ret;
+}
diff --git a/gpg-interface.h b/gpg-interface.h
index 80567e4..beefacb 100644
--- a/gpg-interface.h
+++ b/gpg-interface.h
@@ -17,7 +17,7 @@
 
 struct signature_check {
 	char *payload;
-	char *gpg_output;
+	char *output;
 	char *gpg_status;
 
 	/*
@@ -64,6 +64,12 @@
 int git_gpg_config(const char *, const char *, void *);
 void set_signing_key(const char *);
 const char *get_signing_key(void);
+
+/*
+ * Returns a textual unique representation of the signing key in use
+ * Either a GPG KeyID or a SSH Key Fingerprint
+ */
+const char *get_signing_key_id(void);
 int check_signature(const char *payload, size_t plen,
 		    const char *signature, size_t slen,
 		    struct signature_check *sigc);
diff --git a/grep.c b/grep.c
index 424a395..14fe8a0 100644
--- a/grep.c
+++ b/grep.c
@@ -867,7 +867,7 @@
 	free_pattern_expr(opt->pattern_expression);
 }
 
-static char *end_of_line(char *cp, unsigned long *left)
+static const char *end_of_line(const char *cp, unsigned long *left)
 {
 	unsigned long l = *left;
 	while (l && *cp != '\n') {
@@ -908,7 +908,8 @@
 	opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 }
 
-static int patmatch(struct grep_pat *p, char *line, char *eol,
+static int patmatch(struct grep_pat *p,
+		    const char *line, const char *eol,
 		    regmatch_t *match, int eflags)
 {
 	int hit;
@@ -922,20 +923,16 @@
 	return hit;
 }
 
-static int strip_timestamp(char *bol, char **eol_p)
+static void strip_timestamp(const char *bol, const char **eol_p)
 {
-	char *eol = *eol_p;
-	int ch;
+	const char *eol = *eol_p;
 
 	while (bol < --eol) {
 		if (*eol != '>')
 			continue;
 		*eol_p = ++eol;
-		ch = *eol;
-		*eol = '\0';
-		return ch;
+		break;
 	}
-	return 0;
 }
 
 static struct {
@@ -947,12 +944,12 @@
 	{ "reflog ", 7 },
 };
 
-static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
+static int match_one_pattern(struct grep_pat *p,
+			     const char *bol, const char *eol,
 			     enum grep_context ctx,
 			     regmatch_t *pmatch, int eflags)
 {
 	int hit = 0;
-	int saved_ch = 0;
 	const char *start = bol;
 
 	if ((p->token != GREP_PATTERN) &&
@@ -971,7 +968,7 @@
 		switch (p->field) {
 		case GREP_HEADER_AUTHOR:
 		case GREP_HEADER_COMMITTER:
-			saved_ch = strip_timestamp(bol, &eol);
+			strip_timestamp(bol, &eol);
 			break;
 		default:
 			break;
@@ -1021,8 +1018,6 @@
 				goto again;
 		}
 	}
-	if (p->token == GREP_PATTERN_HEAD && saved_ch)
-		*eol = saved_ch;
 	if (hit) {
 		pmatch[0].rm_so += bol - start;
 		pmatch[0].rm_eo += bol - start;
@@ -1030,8 +1025,9 @@
 	return hit;
 }
 
-static int match_expr_eval(struct grep_opt *opt, struct grep_expr *x, char *bol,
-			   char *eol, enum grep_context ctx, ssize_t *col,
+static int match_expr_eval(struct grep_opt *opt, struct grep_expr *x,
+			   const char *bol, const char *eol,
+			   enum grep_context ctx, ssize_t *col,
 			   ssize_t *icol, int collect_hits)
 {
 	int h = 0;
@@ -1098,7 +1094,8 @@
 	return h;
 }
 
-static int match_expr(struct grep_opt *opt, char *bol, char *eol,
+static int match_expr(struct grep_opt *opt,
+		      const char *bol, const char *eol,
 		      enum grep_context ctx, ssize_t *col,
 		      ssize_t *icol, int collect_hits)
 {
@@ -1106,7 +1103,8 @@
 	return match_expr_eval(opt, x, bol, eol, ctx, col, icol, collect_hits);
 }
 
-static int match_line(struct grep_opt *opt, char *bol, char *eol,
+static int match_line(struct grep_opt *opt,
+		      const char *bol, const char *eol,
 		      ssize_t *col, ssize_t *icol,
 		      enum grep_context ctx, int collect_hits)
 {
@@ -1138,7 +1136,8 @@
 	return hit;
 }
 
-static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
+static int match_next_pattern(struct grep_pat *p,
+			      const char *bol, const char *eol,
 			      enum grep_context ctx,
 			      regmatch_t *pmatch, int eflags)
 {
@@ -1159,7 +1158,8 @@
 	return 1;
 }
 
-static int next_match(struct grep_opt *opt, char *bol, char *eol,
+static int next_match(struct grep_opt *opt,
+		      const char *bol, const char *eol,
 		      enum grep_context ctx, regmatch_t *pmatch, int eflags)
 {
 	struct grep_pat *p;
@@ -1215,7 +1215,8 @@
 	}
 }
 
-static void show_line(struct grep_opt *opt, char *bol, char *eol,
+static void show_line(struct grep_opt *opt,
+		      const char *bol, const char *eol,
 		      const char *name, unsigned lno, ssize_t cno, char sign)
 {
 	int rest = eol - bol;
@@ -1246,7 +1247,6 @@
 	if (opt->color || opt->only_matching) {
 		regmatch_t match;
 		enum grep_context ctx = GREP_CONTEXT_BODY;
-		int ch = *eol;
 		int eflags = 0;
 
 		if (opt->color) {
@@ -1261,7 +1261,6 @@
 			else if (sign == '=')
 				line_color = opt->colors[GREP_COLOR_FUNCTION];
 		}
-		*eol = '\0';
 		while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 			if (match.rm_so == match.rm_eo)
 				break;
@@ -1279,7 +1278,6 @@
 			rest -= match.rm_eo;
 			eflags = REG_NOTBOL;
 		}
-		*eol = ch;
 	}
 	if (!opt->only_matching) {
 		output_color(opt, bol, rest, line_color);
@@ -1307,7 +1305,8 @@
 		pthread_mutex_unlock(&grep_attr_mutex);
 }
 
-static int match_funcname(struct grep_opt *opt, struct grep_source *gs, char *bol, char *eol)
+static int match_funcname(struct grep_opt *opt, struct grep_source *gs,
+			  const char *bol, const char *eol)
 {
 	xdemitconf_t *xecfg = opt->priv;
 	if (xecfg && !xecfg->find_func) {
@@ -1334,10 +1333,10 @@
 }
 
 static void show_funcname_line(struct grep_opt *opt, struct grep_source *gs,
-			       char *bol, unsigned lno)
+			       const char *bol, unsigned lno)
 {
 	while (bol > gs->buf) {
-		char *eol = --bol;
+		const char *eol = --bol;
 
 		while (bol > gs->buf && bol[-1] != '\n')
 			bol--;
@@ -1356,7 +1355,7 @@
 static int is_empty_line(const char *bol, const char *eol);
 
 static void show_pre_context(struct grep_opt *opt, struct grep_source *gs,
-			     char *bol, char *end, unsigned lno)
+			     const char *bol, const char *end, unsigned lno)
 {
 	unsigned cur = lno, from = 1, funcname_lno = 0, orig_from;
 	int funcname_needed = !!opt->funcname, comment_needed = 0;
@@ -1376,8 +1375,8 @@
 
 	/* Rewind. */
 	while (bol > gs->buf && cur > from) {
-		char *next_bol = bol;
-		char *eol = --bol;
+		const char *next_bol = bol;
+		const char *eol = --bol;
 
 		while (bol > gs->buf && bol[-1] != '\n')
 			bol--;
@@ -1408,7 +1407,7 @@
 
 	/* Back forward. */
 	while (cur < lno) {
-		char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
+		const char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
 
 		while (*eol != '\n')
 			eol++;
@@ -1436,12 +1435,12 @@
 static int look_ahead(struct grep_opt *opt,
 		      unsigned long *left_p,
 		      unsigned *lno_p,
-		      char **bol_p)
+		      const char **bol_p)
 {
 	unsigned lno = *lno_p;
-	char *bol = *bol_p;
+	const char *bol = *bol_p;
 	struct grep_pat *p;
-	char *sp, *last_bol;
+	const char *sp, *last_bol;
 	regoff_t earliest = -1;
 
 	for (p = opt->pattern_list; p; p = p->next) {
@@ -1543,8 +1542,8 @@
 
 static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int collect_hits)
 {
-	char *bol;
-	char *peek_bol = NULL;
+	const char *bol;
+	const char *peek_bol = NULL;
 	unsigned long left;
 	unsigned lno = 1;
 	unsigned last_hit = 0;
@@ -1626,7 +1625,7 @@
 	bol = gs->buf;
 	left = gs->size;
 	while (left) {
-		char *eol, ch;
+		const char *eol;
 		int hit;
 		ssize_t cno;
 		ssize_t col = -1, icol = -1;
@@ -1647,14 +1646,11 @@
 		    && look_ahead(opt, &left, &lno, &bol))
 			break;
 		eol = end_of_line(bol, &left);
-		ch = *eol;
-		*eol = 0;
 
 		if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 			ctx = GREP_CONTEXT_BODY;
 
 		hit = match_line(opt, bol, eol, &col, &icol, ctx, collect_hits);
-		*eol = ch;
 
 		if (collect_hits)
 			goto next_line;
@@ -1713,7 +1709,7 @@
 		}
 		if (show_function && (!peek_bol || peek_bol < bol)) {
 			unsigned long peek_left = left;
-			char *peek_eol = eol;
+			const char *peek_eol = eol;
 
 			/*
 			 * Trailing empty lines are not interesting.
@@ -1825,14 +1821,25 @@
 	return grep_source_1(opt, gs, 0);
 }
 
-int grep_buffer(struct grep_opt *opt, char *buf, unsigned long size)
+static void grep_source_init_buf(struct grep_source *gs,
+				 const char *buf,
+				 unsigned long size)
+{
+	gs->type = GREP_SOURCE_BUF;
+	gs->name = NULL;
+	gs->path = NULL;
+	gs->buf = buf;
+	gs->size = size;
+	gs->driver = NULL;
+	gs->identifier = NULL;
+}
+
+int grep_buffer(struct grep_opt *opt, const char *buf, unsigned long size)
 {
 	struct grep_source gs;
 	int r;
 
-	grep_source_init(&gs, GREP_SOURCE_BUF, NULL, NULL, NULL);
-	gs.buf = buf;
-	gs.size = size;
+	grep_source_init_buf(&gs, buf, size);
 
 	r = grep_source(opt, &gs);
 
@@ -1840,28 +1847,30 @@
 	return r;
 }
 
-void grep_source_init(struct grep_source *gs, enum grep_source_type type,
-		      const char *name, const char *path,
-		      const void *identifier)
+void grep_source_init_file(struct grep_source *gs, const char *name,
+			   const char *path)
 {
-	gs->type = type;
+	gs->type = GREP_SOURCE_FILE;
 	gs->name = xstrdup_or_null(name);
 	gs->path = xstrdup_or_null(path);
 	gs->buf = NULL;
 	gs->size = 0;
 	gs->driver = NULL;
+	gs->identifier = xstrdup(path);
+}
 
-	switch (type) {
-	case GREP_SOURCE_FILE:
-		gs->identifier = xstrdup(identifier);
-		break;
-	case GREP_SOURCE_OID:
-		gs->identifier = oiddup(identifier);
-		break;
-	case GREP_SOURCE_BUF:
-		gs->identifier = NULL;
-		break;
-	}
+void grep_source_init_oid(struct grep_source *gs, const char *name,
+			  const char *path, const struct object_id *oid,
+			  struct repository *repo)
+{
+	gs->type = GREP_SOURCE_OID;
+	gs->name = xstrdup_or_null(name);
+	gs->path = xstrdup_or_null(path);
+	gs->buf = NULL;
+	gs->size = 0;
+	gs->driver = NULL;
+	gs->identifier = oiddup(oid);
+	gs->repo = repo;
 }
 
 void grep_source_clear(struct grep_source *gs)
@@ -1877,7 +1886,9 @@
 	switch (gs->type) {
 	case GREP_SOURCE_FILE:
 	case GREP_SOURCE_OID:
-		FREE_AND_NULL(gs->buf);
+		/* these types own the buffer */
+		free((char *)gs->buf);
+		gs->buf = NULL;
 		gs->size = 0;
 		break;
 	case GREP_SOURCE_BUF:
@@ -1890,7 +1901,8 @@
 {
 	enum object_type type;
 
-	gs->buf = read_object_file(gs->identifier, &type, &gs->size);
+	gs->buf = repo_read_object_file(gs->repo, gs->identifier, &type,
+					&gs->size);
 	if (!gs->buf)
 		return error(_("'%s': unable to read %s"),
 			     gs->name,
diff --git a/grep.h b/grep.h
index 72f82b1..3c75ed1 100644
--- a/grep.h
+++ b/grep.h
@@ -120,7 +120,20 @@
 	struct grep_pat *header_list;
 	struct grep_pat **header_tail;
 	struct grep_expr *pattern_expression;
+
+	/*
+	 * NEEDSWORK: See if we can remove this field, because the repository
+	 * should probably be per-source. That is, grep.c functions using this
+	 * field should probably start using "repo" in "struct grep_source"
+	 * instead.
+	 *
+	 * This is potentially the cause of at least one bug - "git grep"
+	 * using the textconv attributes from the superproject on the
+	 * submodules. See the failing "git grep --textconv" tests in
+	 * t7814-grep-recurse-submodules.sh for more information.
+	 */
 	struct repository *repo;
+
 	const char *prefix;
 	int prefix_length;
 	regex_t regexp;
@@ -176,7 +189,7 @@
 void append_header_grep_pattern(struct grep_opt *, enum grep_header_field, const char *);
 void compile_grep_patterns(struct grep_opt *opt);
 void free_grep_patterns(struct grep_opt *opt);
-int grep_buffer(struct grep_opt *opt, char *buf, unsigned long size);
+int grep_buffer(struct grep_opt *opt, const char *buf, unsigned long size);
 
 struct grep_source {
 	char *name;
@@ -187,17 +200,20 @@
 		GREP_SOURCE_BUF,
 	} type;
 	void *identifier;
+	struct repository *repo; /* if GREP_SOURCE_OID */
 
-	char *buf;
+	const char *buf;
 	unsigned long size;
 
 	char *path; /* for attribute lookups */
 	struct userdiff_driver *driver;
 };
 
-void grep_source_init(struct grep_source *gs, enum grep_source_type type,
-		      const char *name, const char *path,
-		      const void *identifier);
+void grep_source_init_file(struct grep_source *gs, const char *name,
+			   const char *path);
+void grep_source_init_oid(struct grep_source *gs, const char *name,
+			  const char *path, const struct object_id *oid,
+			  struct repository *repo);
 void grep_source_clear_data(struct grep_source *gs);
 void grep_source_clear(struct grep_source *gs);
 void grep_source_load_driver(struct grep_source *gs,
@@ -207,7 +223,6 @@
 int grep_source(struct grep_opt *opt, struct grep_source *gs);
 
 struct grep_opt *grep_opt_dup(const struct grep_opt *opt);
-int grep_threads_ok(const struct grep_opt *opt);
 
 /*
  * Mutex used around access to the attributes machinery if
diff --git a/help.c b/help.c
index 3c3bdec..973e47c 100644
--- a/help.c
+++ b/help.c
@@ -11,6 +11,7 @@
 #include "version.h"
 #include "refs.h"
 #include "parse-options.h"
+#include "prompt.h"
 
 struct category_description {
 	uint32_t category;
@@ -292,9 +293,21 @@
 	exclude_cmds(other_cmds, main_cmds);
 }
 
-void list_commands(unsigned int colopts,
-		   struct cmdnames *main_cmds, struct cmdnames *other_cmds)
+static int get_colopts(const char *var, const char *value, void *data)
 {
+	unsigned int *colopts = data;
+
+	if (starts_with(var, "column."))
+		return git_column_config(var, value, "help", colopts);
+
+	return 0;
+}
+
+void list_commands(struct cmdnames *main_cmds, struct cmdnames *other_cmds)
+{
+	unsigned int colopts = 0;
+	git_config(get_colopts, &colopts);
+
 	if (main_cmds->cnt) {
 		const char *exec_path = git_exec_path();
 		printf_ln(_("available git commands in '%s'"), exec_path);
@@ -472,6 +485,7 @@
 static int autocorrect;
 static struct cmdnames aliases;
 
+#define AUTOCORRECT_PROMPT (-3)
 #define AUTOCORRECT_NEVER (-2)
 #define AUTOCORRECT_IMMEDIATELY (-1)
 
@@ -486,6 +500,8 @@
 			autocorrect = AUTOCORRECT_NEVER;
 		} else if (!strcmp(value, "immediate")) {
 			autocorrect = AUTOCORRECT_IMMEDIATELY;
+		} else if (!strcmp(value, "prompt")) {
+			autocorrect = AUTOCORRECT_PROMPT;
 		} else {
 			int v = git_config_int(var, value);
 			autocorrect = (v < 0)
@@ -539,6 +555,12 @@
 
 	read_early_config(git_unknown_cmd_config, NULL);
 
+	/*
+	 * Disable autocorrection prompt in a non-interactive session
+	 */
+	if ((autocorrect == AUTOCORRECT_PROMPT) && (!isatty(0) || !isatty(2)))
+		autocorrect = AUTOCORRECT_NEVER;
+
 	if (autocorrect == AUTOCORRECT_NEVER) {
 		fprintf_ln(stderr, _("git: '%s' is not a git command. See 'git --help'."), cmd);
 		exit(1);
@@ -618,7 +640,16 @@
 				   _("Continuing under the assumption that "
 				     "you meant '%s'."),
 				   assumed);
-		else {
+		else if (autocorrect == AUTOCORRECT_PROMPT) {
+			char *answer;
+			struct strbuf msg = STRBUF_INIT;
+			strbuf_addf(&msg, _("Run '%s' instead? (y/N)"), assumed);
+			answer = git_prompt(msg.buf, PROMPT_ECHO);
+			strbuf_release(&msg);
+			if (!(starts_with(answer, "y") ||
+			      starts_with(answer, "Y")))
+				exit(1);
+		} else {
 			fprintf_ln(stderr,
 				   _("Continuing in %0.1f seconds, "
 				     "assuming that you meant '%s'."),
diff --git a/help.h b/help.h
index 5871e93..9d383f1 100644
--- a/help.h
+++ b/help.h
@@ -37,7 +37,7 @@
 /* Here we require that excludes is a sorted list. */
 void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes);
 int is_in_cmdlist(struct cmdnames *cmds, const char *name);
-void list_commands(unsigned int colopts, struct cmdnames *main_cmds, struct cmdnames *other_cmds);
+void list_commands(struct cmdnames *main_cmds, struct cmdnames *other_cmds);
 void get_version_info(struct strbuf *buf, int show_build_options);
 
 /*
diff --git a/hook.c b/hook.c
new file mode 100644
index 0000000..55e1145
--- /dev/null
+++ b/hook.c
@@ -0,0 +1,42 @@
+#include "cache.h"
+#include "hook.h"
+#include "run-command.h"
+
+const char *find_hook(const char *name)
+{
+	static struct strbuf path = STRBUF_INIT;
+
+	strbuf_reset(&path);
+	strbuf_git_path(&path, "hooks/%s", name);
+	if (access(path.buf, X_OK) < 0) {
+		int err = errno;
+
+#ifdef STRIP_EXTENSION
+		strbuf_addstr(&path, STRIP_EXTENSION);
+		if (access(path.buf, X_OK) >= 0)
+			return path.buf;
+		if (errno == EACCES)
+			err = errno;
+#endif
+
+		if (err == EACCES && advice_enabled(ADVICE_IGNORED_HOOK)) {
+			static struct string_list advise_given = STRING_LIST_INIT_DUP;
+
+			if (!string_list_lookup(&advise_given, name)) {
+				string_list_insert(&advise_given, name);
+				advise(_("The '%s' hook was ignored because "
+					 "it's not set as executable.\n"
+					 "You can disable this warning with "
+					 "`git config advice.ignoredHook false`."),
+				       path.buf);
+			}
+		}
+		return NULL;
+	}
+	return path.buf;
+}
+
+int hook_exists(const char *name)
+{
+	return !!find_hook(name);
+}
diff --git a/hook.h b/hook.h
new file mode 100644
index 0000000..6aa36fc
--- /dev/null
+++ b/hook.h
@@ -0,0 +1,16 @@
+#ifndef HOOK_H
+#define HOOK_H
+
+/*
+ * Returns the path to the hook file, or NULL if the hook is missing
+ * or disabled. Note that this points to static storage that will be
+ * overwritten by further calls to find_hook and run_hook_*.
+ */
+const char *find_hook(const char *name);
+
+/**
+ * A boolean version of find_hook()
+ */
+int hook_exists(const char *hookname);
+
+#endif
diff --git a/http-backend.c b/http-backend.c
index b329bf6..e7c0eea 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -534,7 +534,7 @@
 
 	if (service_name) {
 		const char *argv[] = {NULL /* service name */,
-			"--stateless-rpc", "--advertise-refs",
+			"--http-backend-info-refs",
 			".", NULL};
 		struct rpc_service *svc = select_service(hdr, service_name);
 
@@ -739,6 +739,7 @@
 int cmd_main(int argc, const char **argv)
 {
 	char *method = getenv("REQUEST_METHOD");
+	const char *proto_header;
 	char *dir;
 	struct service_cmd *cmd = NULL;
 	char *cmd_arg = NULL;
@@ -789,6 +790,9 @@
 	http_config();
 	max_request_buffer = git_env_ulong("GIT_HTTP_MAX_REQUEST_BUFFER",
 					   max_request_buffer);
+	proto_header = getenv("HTTP_GIT_PROTOCOL");
+	if (proto_header)
+		setenv(GIT_PROTOCOL_ENVIRONMENT, proto_header, 0);
 
 	cmd->imp(&hdr, cmd_arg);
 	return 0;
diff --git a/http-push.c b/http-push.c
index d7cb167..3309aaf 100644
--- a/http-push.c
+++ b/http-push.c
@@ -203,10 +203,8 @@
 	curl_easy_setopt(curl, CURLOPT_INFILE, buffer);
 	curl_easy_setopt(curl, CURLOPT_INFILESIZE, buffer->buf.len);
 	curl_easy_setopt(curl, CURLOPT_READFUNCTION, fread_buffer);
-#ifndef NO_CURL_IOCTL
 	curl_easy_setopt(curl, CURLOPT_IOCTLFUNCTION, ioctl_buffer);
 	curl_easy_setopt(curl, CURLOPT_IOCTLDATA, buffer);
-#endif
 	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_fn);
 	curl_easy_setopt(curl, CURLOPT_NOBODY, 0);
 	curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, custom_req);
@@ -249,8 +247,6 @@
 	finish_request(request);
 }
 
-#ifdef USE_CURL_MULTI
-
 static void start_fetch_loose(struct transfer_request *request)
 {
 	struct active_request_slot *slot;
@@ -299,7 +295,6 @@
 		FREE_AND_NULL(request->url);
 	}
 }
-#endif
 
 static void start_fetch_packed(struct transfer_request *request)
 {
@@ -605,7 +600,6 @@
 	}
 }
 
-#ifdef USE_CURL_MULTI
 static int is_running_queue;
 static int fill_active_slot(void *unused)
 {
@@ -629,7 +623,6 @@
 	}
 	return 0;
 }
-#endif
 
 static void get_remote_object_list(unsigned char parent);
 
@@ -658,10 +651,8 @@
 	request->next = request_queue_head;
 	request_queue_head = request;
 
-#ifdef USE_CURL_MULTI
 	fill_active_slots();
 	step_active_slots();
-#endif
 }
 
 static int add_send_request(struct object *obj, struct remote_lock *lock)
@@ -696,10 +687,8 @@
 	request->next = request_queue_head;
 	request_queue_head = request;
 
-#ifdef USE_CURL_MULTI
 	fill_active_slots();
 	step_active_slots();
-#endif
 
 	return 1;
 }
@@ -894,7 +883,7 @@
 	slot->results = &results;
 	curl_setup_http(slot->curl, url, DAV_LOCK, &out_buffer, fwrite_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, dav_headers);
-	curl_easy_setopt(slot->curl, CURLOPT_FILE, &in_buffer);
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, &in_buffer);
 
 	CALLOC_ARRAY(lock, 1);
 	lock->timeout = -1;
@@ -1153,7 +1142,7 @@
 	curl_setup_http(slot->curl, url, DAV_PROPFIND,
 			&out_buffer, fwrite_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, dav_headers);
-	curl_easy_setopt(slot->curl, CURLOPT_FILE, &in_buffer);
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, &in_buffer);
 
 	if (start_active_slot(slot)) {
 		run_active_slot(slot);
@@ -1227,7 +1216,7 @@
 	curl_setup_http(slot->curl, repo->url, DAV_PROPFIND,
 			&out_buffer, fwrite_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, dav_headers);
-	curl_easy_setopt(slot->curl, CURLOPT_FILE, &in_buffer);
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, &in_buffer);
 
 	if (start_active_slot(slot)) {
 		run_active_slot(slot);
@@ -1682,21 +1671,15 @@
 
 static void run_request_queue(void)
 {
-#ifdef USE_CURL_MULTI
 	is_running_queue = 1;
 	fill_active_slots();
 	add_fill_function(NULL, fill_active_slot);
-#endif
 	do {
 		finish_all_active_slots();
-#ifdef USE_CURL_MULTI
 		fill_active_slots();
-#endif
 	} while (request_queue_head && !aborted);
 
-#ifdef USE_CURL_MULTI
 	is_running_queue = 0;
-#endif
 }
 
 int cmd_main(int argc, const char **argv)
@@ -1770,10 +1753,6 @@
 		break;
 	}
 
-#ifndef USE_CURL_MULTI
-	die("git-push is not available for http/https repository when not compiled with USE_CURL_MULTI");
-#endif
-
 	if (!repo->url)
 		usage(http_push_usage);
 
@@ -1786,9 +1765,7 @@
 
 	http_init(NULL, repo->url, 1);
 
-#ifdef USE_CURL_MULTI
 	is_running_queue = 0;
-#endif
 
 	/* Verify DAV compliance/lock support */
 	if (!locking_available()) {
diff --git a/http-walker.c b/http-walker.c
index 90d8ecb..910fae5 100644
--- a/http-walker.c
+++ b/http-walker.c
@@ -127,7 +127,6 @@
 	free(obj_req);
 }
 
-#ifdef USE_CURL_MULTI
 static int fill_active_slot(struct walker *walker)
 {
 	struct object_request *obj_req;
@@ -146,7 +145,6 @@
 	}
 	return 0;
 }
-#endif
 
 static void prefetch(struct walker *walker, unsigned char *sha1)
 {
@@ -163,10 +161,8 @@
 	http_is_verbose = walker->get_verbosely;
 	list_add_tail(&newreq->node, &object_queue_head);
 
-#ifdef USE_CURL_MULTI
 	fill_active_slots();
 	step_active_slots();
-#endif
 }
 
 static int is_alternate_allowed(const char *url)
@@ -357,11 +353,9 @@
 	 * wait for them to arrive and return to processing this request's
 	 * curl message
 	 */
-#ifdef USE_CURL_MULTI
 	while (cdata->got_alternates == 0) {
 		step_active_slots();
 	}
-#endif
 
 	/* Nothing to do if they've already been fetched */
 	if (cdata->got_alternates == 1)
@@ -384,7 +378,7 @@
 	alt_req.walker = walker;
 	slot->callback_data = &alt_req;
 
-	curl_easy_setopt(slot->curl, CURLOPT_FILE, &buffer);
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, &buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_URL, url.buf);
 
@@ -505,12 +499,8 @@
 		return 0;
 	}
 
-#ifdef USE_CURL_MULTI
 	while (obj_req->state == WAITING)
 		step_active_slots();
-#else
-	start_object_request(walker, obj_req);
-#endif
 
 	/*
 	 * obj_req->req might change when fetching alternates in the callback
@@ -623,9 +613,7 @@
 	walker->cleanup = cleanup;
 	walker->data = data;
 
-#ifdef USE_CURL_MULTI
 	add_fill_function(walker, (int (*)(void *)) fill_active_slot);
-#endif
 
 	return walker;
 }
diff --git a/http.c b/http.c
index fdb6e22..f92859f 100644
--- a/http.c
+++ b/http.c
@@ -1,4 +1,5 @@
 #include "git-compat-util.h"
+#include "git-curl-compat.h"
 #include "http.h"
 #include "config.h"
 #include "pack.h"
@@ -19,28 +20,16 @@
 static struct trace_key trace_curl = TRACE_KEY_INIT(CURL);
 static int trace_curl_data = 1;
 static int trace_curl_redact = 1;
-#if LIBCURL_VERSION_NUM >= 0x070a08
 long int git_curl_ipresolve = CURL_IPRESOLVE_WHATEVER;
-#else
-long int git_curl_ipresolve;
-#endif
 int active_requests;
 int http_is_verbose;
 ssize_t http_post_buffer = 16 * LARGE_PACKET_MAX;
 
-#if LIBCURL_VERSION_NUM >= 0x070a06
-#define LIBCURL_CAN_HANDLE_AUTH_ANY
-#endif
-
 static int min_curl_sessions = 1;
 static int curl_session_count;
-#ifdef USE_CURL_MULTI
 static int max_requests = -1;
 static CURLM *curlm;
-#endif
-#ifndef NO_CURL_EASY_DUPHANDLE
 static CURL *curl_default;
-#endif
 
 #define PREV_BUF_SIZE 4096
 
@@ -59,25 +48,19 @@
 	{ "sslv2", CURL_SSLVERSION_SSLv2 },
 	{ "sslv3", CURL_SSLVERSION_SSLv3 },
 	{ "tlsv1", CURL_SSLVERSION_TLSv1 },
-#if LIBCURL_VERSION_NUM >= 0x072200
+#ifdef GIT_CURL_HAVE_CURL_SSLVERSION_TLSv1_0
 	{ "tlsv1.0", CURL_SSLVERSION_TLSv1_0 },
 	{ "tlsv1.1", CURL_SSLVERSION_TLSv1_1 },
 	{ "tlsv1.2", CURL_SSLVERSION_TLSv1_2 },
 #endif
-#if LIBCURL_VERSION_NUM >= 0x073400
+#ifdef GIT_CURL_HAVE_CURL_SSLVERSION_TLSv1_3
 	{ "tlsv1.3", CURL_SSLVERSION_TLSv1_3 },
 #endif
 };
-#if LIBCURL_VERSION_NUM >= 0x070903
 static const char *ssl_key;
-#endif
-#if LIBCURL_VERSION_NUM >= 0x070908
 static const char *ssl_capath;
-#endif
-#if LIBCURL_VERSION_NUM >= 0x071304
 static const char *curl_no_proxy;
-#endif
-#if LIBCURL_VERSION_NUM >= 0x072c00
+#ifdef GIT_CURL_HAVE_CURLOPT_PINNEDPUBLICKEY
 static const char *ssl_pinnedkey;
 #endif
 static const char *ssl_cainfo;
@@ -101,9 +84,7 @@
 	{ "digest", CURLAUTH_DIGEST },
 	{ "negotiate", CURLAUTH_GSSNEGOTIATE },
 	{ "ntlm", CURLAUTH_NTLM },
-#ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 	{ "anyauth", CURLAUTH_ANY },
-#endif
 	/*
 	 * CURLAUTH_DIGEST_IE has no corresponding command-line option in
 	 * curl(1) and is not included in CURLAUTH_ANY, so we leave it out
@@ -133,27 +114,15 @@
 
 enum http_follow_config http_follow_config = HTTP_FOLLOW_INITIAL;
 
-#if LIBCURL_VERSION_NUM >= 0x071700
-/* Use CURLOPT_KEYPASSWD as is */
-#elif LIBCURL_VERSION_NUM >= 0x070903
-#define CURLOPT_KEYPASSWD CURLOPT_SSLKEYPASSWD
-#else
-#define CURLOPT_KEYPASSWD CURLOPT_SSLCERTPASSWD
-#endif
-
 static struct credential cert_auth = CREDENTIAL_INIT;
 static int ssl_cert_password_required;
-#ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 static unsigned long http_auth_methods = CURLAUTH_ANY;
 static int http_auth_methods_restricted;
 /* Modes for which empty_auth cannot actually help us. */
 static unsigned long empty_auth_useless =
 	CURLAUTH_BASIC
-#ifdef CURLAUTH_DIGEST_IE
 	| CURLAUTH_DIGEST_IE
-#endif
 	| CURLAUTH_DIGEST;
-#endif
 
 static struct curl_slist *pragma_header;
 static struct curl_slist *no_pragma_header;
@@ -186,7 +155,6 @@
 	return size / eltsize;
 }
 
-#ifndef NO_CURL_IOCTL
 curlioerr ioctl_buffer(CURL *handle, int cmd, void *clientp)
 {
 	struct buffer *buffer = clientp;
@@ -203,7 +171,6 @@
 		return CURLIOE_UNKNOWNCMD;
 	}
 }
-#endif
 
 size_t fwrite_buffer(char *ptr, size_t eltsize, size_t nmemb, void *buffer_)
 {
@@ -237,12 +204,8 @@
 	if (slot->results != NULL) {
 		slot->results->curl_result = slot->curl_result;
 		slot->results->http_code = slot->http_code;
-#if LIBCURL_VERSION_NUM >= 0x070a08
 		curl_easy_getinfo(slot->curl, CURLINFO_HTTPAUTH_AVAIL,
 				  &slot->results->auth_avail);
-#else
-		slot->results->auth_avail = 0;
-#endif
 
 		curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CONNECTCODE,
 			&slot->results->http_connectcode);
@@ -255,12 +218,9 @@
 
 static void xmulti_remove_handle(struct active_request_slot *slot)
 {
-#ifdef USE_CURL_MULTI
 	curl_multi_remove_handle(curlm, slot->curl);
-#endif
 }
 
-#ifdef USE_CURL_MULTI
 static void process_curl_messages(void)
 {
 	int num_messages;
@@ -288,7 +248,6 @@
 		curl_message = curl_multi_info_read(curlm, &num_messages);
 	}
 }
-#endif
 
 static int http_options(const char *var, const char *value, void *cb)
 {
@@ -305,14 +264,10 @@
 		return git_config_string(&ssl_version, var, value);
 	if (!strcmp("http.sslcert", var))
 		return git_config_pathname(&ssl_cert, var, value);
-#if LIBCURL_VERSION_NUM >= 0x070903
 	if (!strcmp("http.sslkey", var))
 		return git_config_pathname(&ssl_key, var, value);
-#endif
-#if LIBCURL_VERSION_NUM >= 0x070908
 	if (!strcmp("http.sslcapath", var))
 		return git_config_pathname(&ssl_capath, var, value);
-#endif
 	if (!strcmp("http.sslcainfo", var))
 		return git_config_pathname(&ssl_cainfo, var, value);
 	if (!strcmp("http.sslcertpasswordprotected", var)) {
@@ -341,18 +296,14 @@
 
 	if (!strcmp("http.minsessions", var)) {
 		min_curl_sessions = git_config_int(var, value);
-#ifndef USE_CURL_MULTI
 		if (min_curl_sessions > 1)
 			min_curl_sessions = 1;
-#endif
 		return 0;
 	}
-#ifdef USE_CURL_MULTI
 	if (!strcmp("http.maxrequests", var)) {
 		max_requests = git_config_int(var, value);
 		return 0;
 	}
-#endif
 	if (!strcmp("http.lowspeedlimit", var)) {
 		curl_low_speed_limit = (long)git_config_int(var, value);
 		return 0;
@@ -423,10 +374,10 @@
 	}
 
 	if (!strcmp("http.pinnedpubkey", var)) {
-#if LIBCURL_VERSION_NUM >= 0x072c00
+#ifdef GIT_CURL_HAVE_CURLOPT_PINNEDPUBLICKEY
 		return git_config_pathname(&ssl_pinnedkey, var, value);
 #else
-		warning(_("Public key pinning not supported with cURL < 7.44.0"));
+		warning(_("Public key pinning not supported with cURL < 7.39.0"));
 		return 0;
 #endif
 	}
@@ -461,12 +412,6 @@
 	if (curl_empty_auth >= 0)
 		return curl_empty_auth;
 
-#ifndef LIBCURL_CAN_HANDLE_AUTH_ANY
-	/*
-	 * Our libcurl is too old to do AUTH_ANY in the first place;
-	 * just default to turning the feature off.
-	 */
-#else
 	/*
 	 * In the automatic case, kick in the empty-auth
 	 * hack as long as we would potentially try some
@@ -479,7 +424,6 @@
 	if (http_auth_methods_restricted &&
 	    (http_auth_methods & ~empty_auth_useless))
 		return 1;
-#endif
 	return 0;
 }
 
@@ -493,24 +437,8 @@
 
 	credential_fill(&http_auth);
 
-#if LIBCURL_VERSION_NUM >= 0x071301
 	curl_easy_setopt(result, CURLOPT_USERNAME, http_auth.username);
 	curl_easy_setopt(result, CURLOPT_PASSWORD, http_auth.password);
-#else
-	{
-		static struct strbuf up = STRBUF_INIT;
-		/*
-		 * Note that we assume we only ever have a single set of
-		 * credentials in a given program run, so we do not have
-		 * to worry about updating this buffer, only setting its
-		 * initial value.
-		 */
-		if (!up.len)
-			strbuf_addf(&up, "%s:%s",
-				http_auth.username, http_auth.password);
-		curl_easy_setopt(result, CURLOPT_USERPWD, up.buf);
-	}
-#endif
 }
 
 /* *var must be free-able */
@@ -524,22 +452,10 @@
 
 static void set_proxyauth_name_password(CURL *result)
 {
-#if LIBCURL_VERSION_NUM >= 0x071301
 		curl_easy_setopt(result, CURLOPT_PROXYUSERNAME,
 			proxy_auth.username);
 		curl_easy_setopt(result, CURLOPT_PROXYPASSWORD,
 			proxy_auth.password);
-#else
-		struct strbuf s = STRBUF_INIT;
-
-		strbuf_addstr_urlencode(&s, proxy_auth.username,
-					is_rfc3986_unreserved);
-		strbuf_addch(&s, ':');
-		strbuf_addstr_urlencode(&s, proxy_auth.password,
-					is_rfc3986_unreserved);
-		curl_proxyuserpwd = strbuf_detach(&s, NULL);
-		curl_easy_setopt(result, CURLOPT_PROXYUSERPWD, curl_proxyuserpwd);
-#endif
 }
 
 static void init_curl_proxy_auth(CURL *result)
@@ -552,7 +468,6 @@
 
 	var_override(&http_proxy_authmethod, getenv("GIT_HTTP_PROXY_AUTHMETHOD"));
 
-#if LIBCURL_VERSION_NUM >= 0x070a07 /* CURLOPT_PROXYAUTH and CURLAUTH_ANY */
 	if (http_proxy_authmethod) {
 		int i;
 		for (i = 0; i < ARRAY_SIZE(proxy_authmethods); i++) {
@@ -570,7 +485,6 @@
 	}
 	else
 		curl_easy_setopt(result, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
-#endif
 }
 
 static int has_cert_password(void)
@@ -587,7 +501,7 @@
 	return 1;
 }
 
-#if LIBCURL_VERSION_NUM >= 0x073400
+#ifdef GIT_CURL_HAVE_CURLOPT_PROXY_KEYPASSWD
 static int has_proxy_cert_password(void)
 {
 	if (http_proxy_ssl_cert == NULL || proxy_ssl_cert_password_required != 1)
@@ -603,13 +517,13 @@
 }
 #endif
 
-#if LIBCURL_VERSION_NUM >= 0x071900
+#ifdef GITCURL_HAVE_CURLOPT_TCP_KEEPALIVE
 static void set_curl_keepalive(CURL *c)
 {
 	curl_easy_setopt(c, CURLOPT_TCP_KEEPALIVE, 1);
 }
 
-#elif LIBCURL_VERSION_NUM >= 0x071000
+#else
 static int sockopt_callback(void *client, curl_socket_t fd, curlsocktype type)
 {
 	int ka = 1;
@@ -623,19 +537,13 @@
 	if (rc < 0)
 		warning_errno("unable to set SO_KEEPALIVE on socket");
 
-	return 0; /* CURL_SOCKOPT_OK only exists since curl 7.21.5 */
+	return CURL_SOCKOPT_OK;
 }
 
 static void set_curl_keepalive(CURL *c)
 {
 	curl_easy_setopt(c, CURLOPT_SOCKOPTFUNCTION, sockopt_callback);
 }
-
-#else
-static void set_curl_keepalive(CURL *c)
-{
-	/* not supported on older curl versions */
-}
 #endif
 
 static void redact_sensitive_header(struct strbuf *header)
@@ -809,7 +717,6 @@
 	curl_easy_setopt(handle, CURLOPT_DEBUGDATA, NULL);
 }
 
-#ifdef CURLPROTO_HTTP
 static long get_curl_allowed_protocols(int from_user)
 {
 	long allowed_protocols = 0;
@@ -825,9 +732,8 @@
 
 	return allowed_protocols;
 }
-#endif
 
-#if LIBCURL_VERSION_NUM >=0x072f00
+#ifdef GIT_CURL_HAVE_CURL_HTTP_VERSION_2
 static int get_curl_http_version_opt(const char *version_string, long *opt)
 {
 	int i;
@@ -869,7 +775,7 @@
 		curl_easy_setopt(result, CURLOPT_SSL_VERIFYHOST, 2);
 	}
 
-#if LIBCURL_VERSION_NUM >= 0x072f00 // 7.47.0
+#ifdef GIT_CURL_HAVE_CURL_HTTP_VERSION_2
     if (curl_http_version) {
 		long opt;
 		if (!get_curl_http_version_opt(curl_http_version, &opt)) {
@@ -879,12 +785,8 @@
     }
 #endif
 
-#if LIBCURL_VERSION_NUM >= 0x070907
 	curl_easy_setopt(result, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
-#endif
-#ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 	curl_easy_setopt(result, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
-#endif
 
 #ifdef CURLGSSAPI_DELEGATION_FLAG
 	if (curl_deleg) {
@@ -904,7 +806,7 @@
 
 	if (http_ssl_backend && !strcmp("schannel", http_ssl_backend) &&
 	    !http_schannel_check_revoke) {
-#if LIBCURL_VERSION_NUM >= 0x072c00
+#ifdef GIT_CURL_HAVE_CURLSSLOPT_NO_REVOKE
 		curl_easy_setopt(result, CURLOPT_SSL_OPTIONS, CURLSSLOPT_NO_REVOKE);
 #else
 		warning(_("CURLSSLOPT_NO_REVOKE not supported with cURL < 7.44.0"));
@@ -940,28 +842,24 @@
 		curl_easy_setopt(result, CURLOPT_SSLCERT, ssl_cert);
 	if (has_cert_password())
 		curl_easy_setopt(result, CURLOPT_KEYPASSWD, cert_auth.password);
-#if LIBCURL_VERSION_NUM >= 0x070903
 	if (ssl_key != NULL)
 		curl_easy_setopt(result, CURLOPT_SSLKEY, ssl_key);
-#endif
-#if LIBCURL_VERSION_NUM >= 0x070908
 	if (ssl_capath != NULL)
 		curl_easy_setopt(result, CURLOPT_CAPATH, ssl_capath);
-#endif
-#if LIBCURL_VERSION_NUM >= 0x072c00
+#ifdef GIT_CURL_HAVE_CURLOPT_PINNEDPUBLICKEY
 	if (ssl_pinnedkey != NULL)
 		curl_easy_setopt(result, CURLOPT_PINNEDPUBLICKEY, ssl_pinnedkey);
 #endif
 	if (http_ssl_backend && !strcmp("schannel", http_ssl_backend) &&
 	    !http_schannel_use_ssl_cainfo) {
 		curl_easy_setopt(result, CURLOPT_CAINFO, NULL);
-#if LIBCURL_VERSION_NUM >= 0x073400
+#ifdef GIT_CURL_HAVE_CURLOPT_PROXY_CAINFO
 		curl_easy_setopt(result, CURLOPT_PROXY_CAINFO, NULL);
 #endif
 	} else if (ssl_cainfo != NULL || http_proxy_ssl_ca_info != NULL) {
 		if (ssl_cainfo != NULL)
 			curl_easy_setopt(result, CURLOPT_CAINFO, ssl_cainfo);
-#if LIBCURL_VERSION_NUM >= 0x073400
+#ifdef GIT_CURL_HAVE_CURLOPT_PROXY_CAINFO
 		if (http_proxy_ssl_ca_info != NULL)
 			curl_easy_setopt(result, CURLOPT_PROXY_CAINFO, http_proxy_ssl_ca_info);
 #endif
@@ -975,19 +873,11 @@
 	}
 
 	curl_easy_setopt(result, CURLOPT_MAXREDIRS, 20);
-#if LIBCURL_VERSION_NUM >= 0x071301
 	curl_easy_setopt(result, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
-#elif LIBCURL_VERSION_NUM >= 0x071101
-	curl_easy_setopt(result, CURLOPT_POST301, 1);
-#endif
-#ifdef CURLPROTO_HTTP
 	curl_easy_setopt(result, CURLOPT_REDIR_PROTOCOLS,
 			 get_curl_allowed_protocols(0));
 	curl_easy_setopt(result, CURLOPT_PROTOCOLS,
 			 get_curl_allowed_protocols(-1));
-#else
-	warning(_("Protocol restrictions not supported with cURL < 7.19.4"));
-#endif
 	if (getenv("GIT_CURL_VERBOSE"))
 		http_trace_curl_no_data();
 	setup_curl_trace(result);
@@ -1002,10 +892,8 @@
 	if (curl_ftp_no_epsv)
 		curl_easy_setopt(result, CURLOPT_FTP_USE_EPSV, 0);
 
-#ifdef CURLOPT_USE_SSL
 	if (curl_ssl_try)
 		curl_easy_setopt(result, CURLOPT_USE_SSL, CURLUSESSL_TRY);
-#endif
 
 	/*
 	 * CURL also examines these variables as a fallback; but we need to query
@@ -1040,7 +928,6 @@
 		 */
 		curl_easy_setopt(result, CURLOPT_PROXY, "");
 	} else if (curl_http_proxy) {
-#if LIBCURL_VERSION_NUM >= 0x071800
 		if (starts_with(curl_http_proxy, "socks5h"))
 			curl_easy_setopt(result,
 				CURLOPT_PROXYTYPE, CURLPROXY_SOCKS5_HOSTNAME);
@@ -1053,8 +940,7 @@
 		else if (starts_with(curl_http_proxy, "socks"))
 			curl_easy_setopt(result,
 				CURLOPT_PROXYTYPE, CURLPROXY_SOCKS4);
-#endif
-#if LIBCURL_VERSION_NUM >= 0x073400
+#ifdef GIT_CURL_HAVE_CURLOPT_PROXY_KEYPASSWD
 		else if (starts_with(curl_http_proxy, "https")) {
 			curl_easy_setopt(result, CURLOPT_PROXYTYPE, CURLPROXY_HTTPS);
 
@@ -1081,11 +967,9 @@
 			die("Invalid proxy URL '%s'", curl_http_proxy);
 
 		curl_easy_setopt(result, CURLOPT_PROXY, proxy_auth.host);
-#if LIBCURL_VERSION_NUM >= 0x071304
 		var_override(&curl_no_proxy, getenv("NO_PROXY"));
 		var_override(&curl_no_proxy, getenv("no_proxy"));
 		curl_easy_setopt(result, CURLOPT_NOPROXY, curl_no_proxy);
-#endif
 	}
 	init_curl_proxy_auth(result);
 
@@ -1106,7 +990,7 @@
 	char *low_speed_limit;
 	char *low_speed_time;
 	char *normalized_url;
-	struct urlmatch_config config = { STRING_LIST_INIT_DUP };
+	struct urlmatch_config config = URLMATCH_CONFIG_INIT;
 
 	config.section = "http";
 	config.key = NULL;
@@ -1121,7 +1005,7 @@
 	free(normalized_url);
 	string_list_clear(&config.vars, 1);
 
-#if LIBCURL_VERSION_NUM >= 0x073800
+#ifdef GIT_CURL_HAVE_CURLSSLSET_NO_BACKENDS
 	if (http_ssl_backend) {
 		const curl_ssl_backend **backends;
 		struct strbuf buf = STRBUF_INIT;
@@ -1164,7 +1048,6 @@
 	no_pragma_header = curl_slist_append(http_copy_default_headers(),
 		"Pragma:");
 
-#ifdef USE_CURL_MULTI
 	{
 		char *http_max_requests = getenv("GIT_HTTP_MAX_REQUESTS");
 		if (http_max_requests != NULL)
@@ -1174,18 +1057,13 @@
 	curlm = curl_multi_init();
 	if (!curlm)
 		die("curl_multi_init failed");
-#endif
 
 	if (getenv("GIT_SSL_NO_VERIFY"))
 		curl_ssl_verify = 0;
 
 	set_from_env(&ssl_cert, "GIT_SSL_CERT");
-#if LIBCURL_VERSION_NUM >= 0x070903
 	set_from_env(&ssl_key, "GIT_SSL_KEY");
-#endif
-#if LIBCURL_VERSION_NUM >= 0x070908
 	set_from_env(&ssl_capath, "GIT_SSL_CAPATH");
-#endif
 	set_from_env(&ssl_cainfo, "GIT_SSL_CAINFO");
 
 	set_from_env(&user_agent, "GIT_HTTP_USER_AGENT");
@@ -1201,10 +1079,8 @@
 		curl_ssl_verify = 1;
 
 	curl_session_count = 0;
-#ifdef USE_CURL_MULTI
 	if (max_requests < 1)
 		max_requests = DEFAULT_MAX_REQUESTS;
-#endif
 
 	set_from_env(&http_proxy_ssl_cert, "GIT_PROXY_SSL_CERT");
 	set_from_env(&http_proxy_ssl_key, "GIT_PROXY_SSL_KEY");
@@ -1224,9 +1100,7 @@
 			ssl_cert_password_required = 1;
 	}
 
-#ifndef NO_CURL_EASY_DUPHANDLE
 	curl_default = get_curl_handle();
-#endif
 }
 
 void http_cleanup(void)
@@ -1244,13 +1118,9 @@
 	}
 	active_queue_head = NULL;
 
-#ifndef NO_CURL_EASY_DUPHANDLE
 	curl_easy_cleanup(curl_default);
-#endif
 
-#ifdef USE_CURL_MULTI
 	curl_multi_cleanup(curlm);
-#endif
 	curl_global_cleanup();
 
 	string_list_clear(&extra_http_headers, 0);
@@ -1297,7 +1167,6 @@
 	struct active_request_slot *slot = active_queue_head;
 	struct active_request_slot *newslot;
 
-#ifdef USE_CURL_MULTI
 	int num_transfers;
 
 	/* Wait for a slot to open up if the queue is full */
@@ -1306,7 +1175,6 @@
 		if (num_transfers < active_requests)
 			process_curl_messages();
 	}
-#endif
 
 	while (slot != NULL && slot->in_use)
 		slot = slot->next;
@@ -1329,11 +1197,7 @@
 	}
 
 	if (slot->curl == NULL) {
-#ifdef NO_CURL_EASY_DUPHANDLE
-		slot->curl = get_curl_handle();
-#else
 		slot->curl = curl_easy_duphandle(curl_default);
-#endif
 		curl_session_count++;
 	}
 
@@ -1367,12 +1231,8 @@
 	else
 		curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 0);
 
-#if LIBCURL_VERSION_NUM >= 0x070a08
 	curl_easy_setopt(slot->curl, CURLOPT_IPRESOLVE, git_curl_ipresolve);
-#endif
-#ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPAUTH, http_auth_methods);
-#endif
 	if (http_auth.password || curl_empty_auth_enabled())
 		init_curl_http_auth(slot->curl);
 
@@ -1381,7 +1241,6 @@
 
 int start_active_slot(struct active_request_slot *slot)
 {
-#ifdef USE_CURL_MULTI
 	CURLMcode curlm_result = curl_multi_add_handle(curlm, slot->curl);
 	int num_transfers;
 
@@ -1399,11 +1258,9 @@
 	 * something.
 	 */
 	curl_multi_perform(curlm, &num_transfers);
-#endif
 	return 1;
 }
 
-#ifdef USE_CURL_MULTI
 struct fill_chain {
 	void *data;
 	int (*fill)(void *);
@@ -1462,11 +1319,9 @@
 		fill_active_slots();
 	}
 }
-#endif
 
 void run_active_slot(struct active_request_slot *slot)
 {
-#ifdef USE_CURL_MULTI
 	fd_set readfds;
 	fd_set writefds;
 	fd_set excfds;
@@ -1479,7 +1334,6 @@
 		step_active_slots();
 
 		if (slot->in_use) {
-#if LIBCURL_VERSION_NUM >= 0x070f04
 			long curl_timeout;
 			curl_multi_timeout(curlm, &curl_timeout);
 			if (curl_timeout == 0) {
@@ -1491,10 +1345,6 @@
 				select_timeout.tv_sec  =  curl_timeout / 1000;
 				select_timeout.tv_usec = (curl_timeout % 1000) * 1000;
 			}
-#else
-			select_timeout.tv_sec  = 0;
-			select_timeout.tv_usec = 50000;
-#endif
 
 			max_fd = -1;
 			FD_ZERO(&readfds);
@@ -1517,12 +1367,6 @@
 			select(max_fd+1, &readfds, &writefds, &excfds, &select_timeout);
 		}
 	}
-#else
-	while (slot->in_use) {
-		slot->curl_result = curl_easy_perform(slot->curl);
-		finish_active_slot(slot);
-	}
-#endif
 }
 
 static void release_active_slot(struct active_request_slot *slot)
@@ -1536,9 +1380,7 @@
 			curl_session_count--;
 		}
 	}
-#ifdef USE_CURL_MULTI
 	fill_active_slots();
-#endif
 }
 
 void finish_all_active_slots(void)
@@ -1647,6 +1489,10 @@
 		 */
 		credential_reject(&cert_auth);
 		return HTTP_NOAUTH;
+#ifdef GIT_CURL_HAVE_CURLE_SSL_PINNEDPUBKEYNOTMATCH
+	} else if (results->curl_result == CURLE_SSL_PINNEDPUBKEYNOTMATCH) {
+		return HTTP_NOMATCHPUBLICKEY;
+#endif
 	} else if (missing_target(results))
 		return HTTP_MISSING_TARGET;
 	else if (results->http_code == 401) {
@@ -1654,24 +1500,20 @@
 			credential_reject(&http_auth);
 			return HTTP_NOAUTH;
 		} else {
-#ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 			http_auth_methods &= ~CURLAUTH_GSSNEGOTIATE;
 			if (results->auth_avail) {
 				http_auth_methods &= results->auth_avail;
 				http_auth_methods_restricted = 1;
 			}
-#endif
 			return HTTP_REAUTH;
 		}
 	} else {
 		if (results->http_connectcode == 407)
 			credential_reject(&proxy_auth);
-#if LIBCURL_VERSION_NUM >= 0x070c00
 		if (!curl_errorstr[0])
 			strlcpy(curl_errorstr,
 				curl_easy_strerror(results->curl_result),
 				sizeof(curl_errorstr));
-#endif
 		return HTTP_ERROR;
 	}
 }
@@ -1930,7 +1772,7 @@
 		curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 1);
 	} else {
 		curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
-		curl_easy_setopt(slot->curl, CURLOPT_FILE, result);
+		curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, result);
 
 		if (target == HTTP_REQUEST_FILE) {
 			off_t posn = ftello(result);
@@ -2347,7 +2189,7 @@
 	}
 
 	preq->slot = get_active_slot();
-	curl_easy_setopt(preq->slot->curl, CURLOPT_FILE, preq->packfile);
+	curl_easy_setopt(preq->slot->curl, CURLOPT_WRITEDATA, preq->packfile);
 	curl_easy_setopt(preq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite);
 	curl_easy_setopt(preq->slot->curl, CURLOPT_URL, preq->url);
 	curl_easy_setopt(preq->slot->curl, CURLOPT_HTTPHEADER,
@@ -2518,7 +2360,7 @@
 
 	freq->slot = get_active_slot();
 
-	curl_easy_setopt(freq->slot->curl, CURLOPT_FILE, freq);
+	curl_easy_setopt(freq->slot->curl, CURLOPT_WRITEDATA, freq);
 	curl_easy_setopt(freq->slot->curl, CURLOPT_FAILONERROR, 0);
 	curl_easy_setopt(freq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
 	curl_easy_setopt(freq->slot->curl, CURLOPT_ERRORBUFFER, freq->errorstr);
diff --git a/http.h b/http.h
index bf3d127..df1590e 100644
--- a/http.h
+++ b/http.h
@@ -10,49 +10,7 @@
 #include "remote.h"
 #include "url.h"
 
-/*
- * We detect based on the cURL version if multi-transfer is
- * usable in this implementation and define this symbol accordingly.
- * This shouldn't be set by the Makefile or by the user (e.g. via CFLAGS).
- */
-#undef USE_CURL_MULTI
-
-#if LIBCURL_VERSION_NUM >= 0x071000
-#define USE_CURL_MULTI
 #define DEFAULT_MAX_REQUESTS 5
-#endif
-
-#if LIBCURL_VERSION_NUM < 0x070704
-#define curl_global_cleanup() do { /* nothing */ } while (0)
-#endif
-
-#if LIBCURL_VERSION_NUM < 0x070800
-#define curl_global_init(a) do { /* nothing */ } while (0)
-#elif LIBCURL_VERSION_NUM >= 0x070c00
-#define curl_global_init(a) curl_global_init_mem(a, xmalloc, free, \
-						xrealloc, xstrdup, xcalloc)
-#endif
-
-#if (LIBCURL_VERSION_NUM < 0x070c04) || (LIBCURL_VERSION_NUM == 0x071000)
-#define NO_CURL_EASY_DUPHANDLE
-#endif
-
-#if LIBCURL_VERSION_NUM < 0x070a03
-#define CURLE_HTTP_RETURNED_ERROR CURLE_HTTP_NOT_FOUND
-#endif
-
-#if LIBCURL_VERSION_NUM < 0x070c03
-#define NO_CURL_IOCTL
-#endif
-
-/*
- * CURLOPT_USE_SSL was known as CURLOPT_FTP_SSL up to 7.16.4,
- * and the constants were known as CURLFTPSSL_*
-*/
-#if !defined(CURLOPT_USE_SSL) && defined(CURLOPT_FTP_SSL)
-#define CURLOPT_USE_SSL CURLOPT_FTP_SSL
-#define CURLUSESSL_TRY CURLFTPSSL_TRY
-#endif
 
 struct slot_results {
 	CURLcode curl_result;
@@ -82,9 +40,7 @@
 size_t fread_buffer(char *ptr, size_t eltsize, size_t nmemb, void *strbuf);
 size_t fwrite_buffer(char *ptr, size_t eltsize, size_t nmemb, void *strbuf);
 size_t fwrite_null(char *ptr, size_t eltsize, size_t nmemb, void *strbuf);
-#ifndef NO_CURL_IOCTL
 curlioerr ioctl_buffer(CURL *handle, int cmd, void *clientp);
-#endif
 
 /* Slot lifecycle functions */
 struct active_request_slot *get_active_slot(void);
@@ -101,11 +57,9 @@
 int run_one_slot(struct active_request_slot *slot,
 		 struct slot_results *results);
 
-#ifdef USE_CURL_MULTI
 void fill_active_slots(void);
 void add_fill_function(void *data, int (*fill)(void *));
 void step_active_slots(void);
-#endif
 
 void http_init(struct remote *remote, const char *url,
 	       int proactive_auth);
@@ -200,6 +154,7 @@
 #define HTTP_START_FAILED	3
 #define HTTP_REAUTH	4
 #define HTTP_NOAUTH	5
+#define HTTP_NOMATCHPUBLICKEY	6
 
 /*
  * Requests a URL and stores the result in a strbuf.
diff --git a/imap-send.c b/imap-send.c
index a0540ba..e6090a0 100644
--- a/imap-send.c
+++ b/imap-send.c
@@ -1441,7 +1441,7 @@
 	curl_easy_setopt(curl, CURLOPT_PORT, server.port);
 
 	if (server.auth_method) {
-#if LIBCURL_VERSION_NUM < 0x072200
+#ifndef GIT_CURL_HAVE_CURLOPT_LOGIN_OPTIONS
 		warning("No LOGIN_OPTIONS support in this cURL version");
 #else
 		struct strbuf auth = STRBUF_INIT;
@@ -1517,11 +1517,7 @@
 	if (cred.username) {
 		if (res == CURLE_OK)
 			credential_approve(&cred);
-#if LIBCURL_VERSION_NUM >= 0x070d01
 		else if (res == CURLE_LOGIN_DENIED)
-#else
-		else
-#endif
 			credential_reject(&cred);
 	}
 
diff --git a/list-objects.c b/list-objects.c
index 473a332..2f623f8 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -337,8 +337,8 @@
 	add_pending_object(revs, &tree->object, "");
 }
 
-static void traverse_trees_and_blobs(struct traversal_context *ctx,
-				     struct strbuf *base)
+static void traverse_non_commits(struct traversal_context *ctx,
+				 struct strbuf *base)
 {
 	int i;
 
@@ -410,9 +410,9 @@
 			 * needs a reallocation for each commit. Can we pass the
 			 * tree directory without allocation churn?
 			 */
-			traverse_trees_and_blobs(ctx, &csp);
+			traverse_non_commits(ctx, &csp);
 	}
-	traverse_trees_and_blobs(ctx, &csp);
+	traverse_non_commits(ctx, &csp);
 	strbuf_release(&csp);
 }
 
diff --git a/list.h b/list.h
index eb60119..362a4cd 100644
--- a/list.h
+++ b/list.h
@@ -46,7 +46,10 @@
 #define INIT_LIST_HEAD(ptr) \
 	(ptr)->next = (ptr)->prev = (ptr)
 
-#define LIST_HEAD_INIT(name) { &(name), &(name) }
+#define LIST_HEAD_INIT(name) { \
+	.next = &(name), \
+	.prev = &(name), \
+}
 
 /* Add new element at the head of the list. */
 static inline void list_add(struct list_head *newp, struct list_head *head)
diff --git a/lockfile.h b/lockfile.h
index db93e6b..90af4e6 100644
--- a/lockfile.h
+++ b/lockfile.h
@@ -121,7 +121,7 @@
 	struct tempfile *tempfile;
 };
 
-#define LOCK_INIT { NULL }
+#define LOCK_INIT { 0 }
 
 /* String appended to a filename to derive the lockfile name: */
 #define LOCK_SUFFIX ".lock"
diff --git a/log-tree.c b/log-tree.c
index 6dc4412..644893f 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -515,10 +515,10 @@
 
 	status = check_signature(payload.buf, payload.len, signature.buf,
 				 signature.len, &sigc);
-	if (status && !sigc.gpg_output)
+	if (status && !sigc.output)
 		show_sig_lines(opt, status, "No signature\n");
 	else
-		show_sig_lines(opt, status, sigc.gpg_output);
+		show_sig_lines(opt, status, sigc.output);
 	signature_check_clear(&sigc);
 
  out:
@@ -585,8 +585,8 @@
 		/* could have a good signature */
 		status = check_signature(payload.buf, payload.len,
 					 signature.buf, signature.len, &sigc);
-		if (sigc.gpg_output)
-			strbuf_addstr(&verify_message, sigc.gpg_output);
+		if (sigc.output)
+			strbuf_addstr(&verify_message, sigc.output);
 		else
 			strbuf_addstr(&verify_message, "No signature\n");
 		signature_check_clear(&sigc);
diff --git a/log-tree.h b/log-tree.h
index 1e8c91d..e7e4641 100644
--- a/log-tree.h
+++ b/log-tree.h
@@ -14,10 +14,8 @@
 };
 
 int parse_decorate_color_config(const char *var, const char *slot_name, const char *value);
-void init_log_tree_opt(struct rev_info *);
 int log_tree_diff_flush(struct rev_info *);
 int log_tree_commit(struct rev_info *, struct commit *);
-int log_tree_opt_parse(struct rev_info *, const char **, int);
 void show_log(struct rev_info *opt);
 void format_decorations_extended(struct strbuf *sb, const struct commit *commit,
 			     int use_color,
diff --git a/ls-refs.c b/ls-refs.c
index 88f6c3f..5407832 100644
--- a/ls-refs.c
+++ b/ls-refs.c
@@ -41,6 +41,12 @@
 }
 
 /*
+ * If we see this many or more "ref-prefix" lines from the client, we consider
+ * it "too many" and will avoid using the prefix feature entirely.
+ */
+#define TOO_MANY_PREFIXES 65536
+
+/*
  * Check if one of the prefixes is a prefix of the ref.
  * If no prefixes were provided, all refs match.
  */
@@ -65,6 +71,7 @@
 	unsigned peel;
 	unsigned symrefs;
 	struct strvec prefixes;
+	struct strbuf buf;
 	unsigned unborn : 1;
 };
 
@@ -73,7 +80,8 @@
 {
 	struct ls_refs_data *data = cb_data;
 	const char *refname_nons = strip_namespace(refname);
-	struct strbuf refline = STRBUF_INIT;
+
+	strbuf_reset(&data->buf);
 
 	if (ref_is_hidden(refname_nons, refname))
 		return 0;
@@ -82,9 +90,9 @@
 		return 0;
 
 	if (oid)
-		strbuf_addf(&refline, "%s %s", oid_to_hex(oid), refname_nons);
+		strbuf_addf(&data->buf, "%s %s", oid_to_hex(oid), refname_nons);
 	else
-		strbuf_addf(&refline, "unborn %s", refname_nons);
+		strbuf_addf(&data->buf, "unborn %s", refname_nons);
 	if (data->symrefs && flag & REF_ISSYMREF) {
 		struct object_id unused;
 		const char *symref_target = resolve_ref_unsafe(refname, 0,
@@ -94,20 +102,19 @@
 		if (!symref_target)
 			die("'%s' is a symref but it is not?", refname);
 
-		strbuf_addf(&refline, " symref-target:%s",
+		strbuf_addf(&data->buf, " symref-target:%s",
 			    strip_namespace(symref_target));
 	}
 
 	if (data->peel && oid) {
 		struct object_id peeled;
 		if (!peel_iterated_oid(oid, &peeled))
-			strbuf_addf(&refline, " peeled:%s", oid_to_hex(&peeled));
+			strbuf_addf(&data->buf, " peeled:%s", oid_to_hex(&peeled));
 	}
 
-	strbuf_addch(&refline, '\n');
-	packet_write(1, refline.buf, refline.len);
+	strbuf_addch(&data->buf, '\n');
+	packet_fwrite(stdout, data->buf.buf, data->buf.len);
 
-	strbuf_release(&refline);
 	return 0;
 }
 
@@ -138,13 +145,13 @@
 	return parse_hide_refs_config(var, value, "uploadpack");
 }
 
-int ls_refs(struct repository *r, struct strvec *keys,
-	    struct packet_reader *request)
+int ls_refs(struct repository *r, struct packet_reader *request)
 {
 	struct ls_refs_data data;
 
 	memset(&data, 0, sizeof(data));
 	strvec_init(&data.prefixes);
+	strbuf_init(&data.buf, 0);
 
 	ensure_config_read();
 	git_config(ls_refs_config, NULL);
@@ -157,22 +164,35 @@
 			data.peel = 1;
 		else if (!strcmp("symrefs", arg))
 			data.symrefs = 1;
-		else if (skip_prefix(arg, "ref-prefix ", &out))
-			strvec_push(&data.prefixes, out);
+		else if (skip_prefix(arg, "ref-prefix ", &out)) {
+			if (data.prefixes.nr < TOO_MANY_PREFIXES)
+				strvec_push(&data.prefixes, out);
+		}
 		else if (!strcmp("unborn", arg))
 			data.unborn = allow_unborn;
+		else
+			die(_("unexpected line: '%s'"), arg);
 	}
 
 	if (request->status != PACKET_READ_FLUSH)
 		die(_("expected flush after ls-refs arguments"));
 
+	/*
+	 * If we saw too many prefixes, we must avoid using them at all; as
+	 * soon as we have any prefix, they are meant to form a comprehensive
+	 * list.
+	 */
+	if (data.prefixes.nr >= TOO_MANY_PREFIXES)
+		strvec_clear(&data.prefixes);
+
 	send_possibly_unborn_head(&data);
 	if (!data.prefixes.nr)
 		strvec_push(&data.prefixes, "");
 	for_each_fullref_in_prefixes(get_git_namespace(), data.prefixes.v,
-				     send_ref, &data, 0);
-	packet_flush(1);
+				     send_ref, &data);
+	packet_fflush(stdout);
 	strvec_clear(&data.prefixes);
+	strbuf_release(&data.buf);
 	return 0;
 }
 
diff --git a/ls-refs.h b/ls-refs.h
index a99e4be..e2243a5 100644
--- a/ls-refs.h
+++ b/ls-refs.h
@@ -2,10 +2,8 @@
 #define LS_REFS_H
 
 struct repository;
-struct strvec;
 struct packet_reader;
-int ls_refs(struct repository *r, struct strvec *keys,
-	    struct packet_reader *request);
+int ls_refs(struct repository *r, struct packet_reader *request);
 int ls_refs_advertise(struct repository *r, struct strbuf *value);
 
 #endif /* LS_REFS_H */
diff --git a/merge-ort.c b/merge-ort.c
index b346e23..0342f10 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -32,6 +32,7 @@
 #include "promisor-remote.h"
 #include "revision.h"
 #include "strmap.h"
+#include "submodule-config.h"
 #include "submodule.h"
 #include "tree.h"
 #include "unpack-trees.h"
@@ -303,8 +304,6 @@
 	 *   * these keys serve to intern all the path strings, which allows
 	 *     us to do pointer comparison on directory names instead of
 	 *     strcmp; we just have to be careful to use the interned strings.
-	 *     (Technically paths_to_free may track some strings that were
-	 *      removed from froms paths.)
 	 *
 	 * The values of paths:
 	 *   * either a pointer to a merged_info, or a conflict_info struct
@@ -340,14 +339,14 @@
 	struct strmap conflicted;
 
 	/*
-	 * paths_to_free: additional list of strings to free
+	 * pool: memory pool for fast allocation/deallocation
 	 *
-	 * If keys are removed from "paths", they are added to paths_to_free
-	 * to ensure they are later freed.  We avoid free'ing immediately since
-	 * other places (e.g. conflict_info.pathnames[]) may still be
-	 * referencing these paths.
+	 * We allocate room for lots of filenames and auxiliary data
+	 * structures in merge_options_internal, and it tends to all be
+	 * freed together too.  Using a memory pool for these provides a
+	 * nice speedup.
 	 */
-	struct string_list paths_to_free;
+	struct mem_pool pool;
 
 	/*
 	 * output: special messages and conflict notices for various paths
@@ -519,64 +518,45 @@
 {
 	struct rename_info *renames = &opti->renames;
 	int i;
-	void (*strmap_func)(struct strmap *, int) =
+	void (*strmap_clear_func)(struct strmap *, int) =
 		reinitialize ? strmap_partial_clear : strmap_clear;
-	void (*strintmap_func)(struct strintmap *) =
+	void (*strintmap_clear_func)(struct strintmap *) =
 		reinitialize ? strintmap_partial_clear : strintmap_clear;
-	void (*strset_func)(struct strset *) =
+	void (*strset_clear_func)(struct strset *) =
 		reinitialize ? strset_partial_clear : strset_clear;
 
-	/*
-	 * We marked opti->paths with strdup_strings = 0, so that we
-	 * wouldn't have to make another copy of the fullpath created by
-	 * make_traverse_path from setup_path_info().  But, now that we've
-	 * used it and have no other references to these strings, it is time
-	 * to deallocate them.
-	 */
-	free_strmap_strings(&opti->paths);
-	strmap_func(&opti->paths, 1);
+	strmap_clear_func(&opti->paths, 0);
 
 	/*
 	 * All keys and values in opti->conflicted are a subset of those in
 	 * opti->paths.  We don't want to deallocate anything twice, so we
 	 * don't free the keys and we pass 0 for free_values.
 	 */
-	strmap_func(&opti->conflicted, 0);
-
-	/*
-	 * opti->paths_to_free is similar to opti->paths; we created it with
-	 * strdup_strings = 0 to avoid making _another_ copy of the fullpath
-	 * but now that we've used it and have no other references to these
-	 * strings, it is time to deallocate them.  We do so by temporarily
-	 * setting strdup_strings to 1.
-	 */
-	opti->paths_to_free.strdup_strings = 1;
-	string_list_clear(&opti->paths_to_free, 0);
-	opti->paths_to_free.strdup_strings = 0;
+	strmap_clear_func(&opti->conflicted, 0);
 
 	if (opti->attr_index.cache_nr) /* true iff opt->renormalize */
 		discard_index(&opti->attr_index);
 
 	/* Free memory used by various renames maps */
 	for (i = MERGE_SIDE1; i <= MERGE_SIDE2; ++i) {
-		strintmap_func(&renames->dirs_removed[i]);
-		strmap_func(&renames->dir_renames[i], 0);
-		strintmap_func(&renames->relevant_sources[i]);
+		strintmap_clear_func(&renames->dirs_removed[i]);
+		strmap_clear_func(&renames->dir_renames[i], 0);
+		strintmap_clear_func(&renames->relevant_sources[i]);
 		if (!reinitialize)
 			assert(renames->cached_pairs_valid_side == 0);
 		if (i != renames->cached_pairs_valid_side &&
 		    -1 != renames->cached_pairs_valid_side) {
-			strset_func(&renames->cached_target_names[i]);
-			strmap_func(&renames->cached_pairs[i], 1);
-			strset_func(&renames->cached_irrelevant[i]);
+			strset_clear_func(&renames->cached_target_names[i]);
+			strmap_clear_func(&renames->cached_pairs[i], 1);
+			strset_clear_func(&renames->cached_irrelevant[i]);
 			partial_clear_dir_rename_count(&renames->dir_rename_count[i]);
 			if (!reinitialize)
 				strmap_clear(&renames->dir_rename_count[i], 1);
 		}
 	}
 	for (i = MERGE_SIDE1; i <= MERGE_SIDE2; ++i) {
-		strintmap_func(&renames->deferred[i].possible_trivial_merges);
-		strset_func(&renames->deferred[i].target_dirs);
+		strintmap_clear_func(&renames->deferred[i].possible_trivial_merges);
+		strset_clear_func(&renames->deferred[i].target_dirs);
 		renames->deferred[i].trivial_merges_okay = 1; /* 1 == maybe */
 	}
 	renames->cached_pairs_valid_side = 0;
@@ -603,6 +583,8 @@
 		strmap_clear(&opti->output, 0);
 	}
 
+	mem_pool_discard(&opti->pool, 0);
+
 	/* Clean out callback_data as well. */
 	FREE_AND_NULL(renames->callback_data);
 	renames->callback_data_nr = renames->callback_data_alloc = 0;
@@ -627,6 +609,7 @@
 
 static void format_commit(struct strbuf *sb,
 			  int indent,
+			  struct repository *repo,
 			  struct commit *commit)
 {
 	struct merge_remote_desc *desc;
@@ -640,7 +623,7 @@
 		return;
 	}
 
-	format_commit_message(commit, "%h %s", sb, &ctx);
+	repo_format_commit_message(repo, commit, "%h %s", sb, &ctx);
 	strbuf_addch(sb, '\n');
 }
 
@@ -665,6 +648,36 @@
 	strbuf_addch(sb, '\n');
 }
 
+static struct diff_filespec *pool_alloc_filespec(struct mem_pool *pool,
+						 const char *path)
+{
+	/* Similar to alloc_filespec(), but allocate from pool and reuse path */
+	struct diff_filespec *spec;
+
+	spec = mem_pool_calloc(pool, 1, sizeof(*spec));
+	spec->path = (char*)path; /* spec won't modify it */
+
+	spec->count = 1;
+	spec->is_binary = -1;
+	return spec;
+}
+
+static struct diff_filepair *pool_diff_queue(struct mem_pool *pool,
+					     struct diff_queue_struct *queue,
+					     struct diff_filespec *one,
+					     struct diff_filespec *two)
+{
+	/* Same code as diff_queue(), except allocate from pool */
+	struct diff_filepair *dp;
+
+	dp = mem_pool_calloc(pool, 1, sizeof(*dp));
+	dp->one = one;
+	dp->two = two;
+	if (queue)
+		diff_q(queue, dp);
+	return dp;
+}
+
 /* add a string to a strbuf, but converting "/" to "_" */
 static void add_flattened_path(struct strbuf *out, const char *s)
 {
@@ -793,8 +806,9 @@
 	assert(!df_conflict || !resolved); /* df_conflict implies !resolved */
 	assert(resolved == (merged_version != NULL));
 
-	mi = xcalloc(1, resolved ? sizeof(struct merged_info) :
-				   sizeof(struct conflict_info));
+	mi = mem_pool_calloc(&opt->priv->pool, 1,
+			     resolved ? sizeof(struct merged_info) :
+					sizeof(struct conflict_info));
 	mi->directory_name = current_dir_name;
 	mi->basename_offset = current_dir_name_len;
 	mi->clean = !!resolved;
@@ -891,11 +905,11 @@
 			return;
 	}
 
-	one = alloc_filespec(pathname);
-	two = alloc_filespec(pathname);
+	one = pool_alloc_filespec(&opt->priv->pool, pathname);
+	two = pool_alloc_filespec(&opt->priv->pool, pathname);
 	fill_filespec(is_add ? two : one,
 		      &names[names_idx].oid, 1, names[names_idx].mode);
-	diff_queue(&renames->pairs[side], one, two);
+	pool_diff_queue(&opt->priv->pool, &renames->pairs[side], one, two);
 }
 
 static void collect_rename_info(struct merge_options *opt,
@@ -1086,7 +1100,7 @@
 	len = traverse_path_len(info, p->pathlen);
 
 	/* +1 in both of the following lines to include the NUL byte */
-	fullpath = xmalloc(len + 1);
+	fullpath = mem_pool_alloc(&opt->priv->pool, len + 1);
 	make_traverse_path(fullpath, len + 1, info, p->path, p->pathlen);
 
 	/*
@@ -1341,7 +1355,7 @@
 		copy = renames->deferred[side].possible_trivial_merges;
 		strintmap_init_with_options(&renames->deferred[side].possible_trivial_merges,
 					    0,
-					    NULL,
+					    &opt->priv->pool,
 					    0);
 		strintmap_for_each_entry(&copy, &iter, entry) {
 			const char *path = entry->key;
@@ -1499,7 +1513,6 @@
 	xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
 		  oid_to_hex(&a->object.oid));
 	repo_init_revisions(repo, &revs, NULL);
-	rev_opts.submodule = path;
 	/* FIXME: can't handle linked worktrees in submodules yet */
 	revs.single_worktree = path != NULL;
 	setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);
@@ -1509,7 +1522,7 @@
 		die("revision walk setup failed");
 	while ((commit = get_revision(&revs)) != NULL) {
 		struct object *o = &(commit->object);
-		if (in_merge_bases(b, commit))
+		if (repo_in_merge_bases(repo, b, commit))
 			add_object_array(o, NULL, &merges);
 	}
 	reset_revision_walk();
@@ -1524,7 +1537,7 @@
 		contains_another = 0;
 		for (j = 0; j < merges.nr; j++) {
 			struct commit *m2 = (struct commit *) merges.objects[j].item;
-			if (i != j && in_merge_bases(m2, m1)) {
+			if (i != j && repo_in_merge_bases(repo, m2, m1)) {
 				contains_another = 1;
 				break;
 			}
@@ -1545,10 +1558,12 @@
 			   const struct object_id *b,
 			   struct object_id *result)
 {
+	struct repository subrepo;
+	struct strbuf sb = STRBUF_INIT;
+	int ret = 0;
 	struct commit *commit_o, *commit_a, *commit_b;
 	int parent_count;
 	struct object_array merges;
-	struct strbuf sb = STRBUF_INIT;
 
 	int i;
 	int search = !opt->priv->call_depth;
@@ -1564,46 +1579,48 @@
 	if (is_null_oid(b))
 		return 0;
 
-	if (add_submodule_odb(path)) {
+	if (repo_submodule_init(&subrepo, opt->repo, path, null_oid())) {
 		path_msg(opt, path, 0,
-			 _("Failed to merge submodule %s (not checked out)"),
-			 path);
+				_("Failed to merge submodule %s (not checked out)"),
+				path);
 		return 0;
 	}
 
-	if (!(commit_o = lookup_commit_reference(opt->repo, o)) ||
-	    !(commit_a = lookup_commit_reference(opt->repo, a)) ||
-	    !(commit_b = lookup_commit_reference(opt->repo, b))) {
+	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,
 			 _("Failed to merge submodule %s (commits not present)"),
 			 path);
-		return 0;
+		goto cleanup;
 	}
 
 	/* check whether both changes are forward */
-	if (!in_merge_bases(commit_o, commit_a) ||
-	    !in_merge_bases(commit_o, commit_b)) {
+	if (!repo_in_merge_bases(&subrepo, commit_o, commit_a) ||
+	    !repo_in_merge_bases(&subrepo, commit_o, commit_b)) {
 		path_msg(opt, path, 0,
 			 _("Failed to merge submodule %s "
 			   "(commits don't follow merge-base)"),
 			 path);
-		return 0;
+		goto cleanup;
 	}
 
 	/* Case #1: a is contained in b or vice versa */
-	if (in_merge_bases(commit_a, commit_b)) {
+	if (repo_in_merge_bases(&subrepo, commit_a, commit_b)) {
 		oidcpy(result, b);
 		path_msg(opt, path, 1,
 			 _("Note: Fast-forwarding submodule %s to %s"),
 			 path, oid_to_hex(b));
-		return 1;
+		ret = 1;
+		goto cleanup;
 	}
-	if (in_merge_bases(commit_b, commit_a)) {
+	if (repo_in_merge_bases(&subrepo, commit_b, commit_a)) {
 		oidcpy(result, a);
 		path_msg(opt, path, 1,
 			 _("Note: Fast-forwarding submodule %s to %s"),
 			 path, oid_to_hex(a));
-		return 1;
+		ret = 1;
+		goto cleanup;
 	}
 
 	/*
@@ -1615,10 +1632,10 @@
 
 	/* Skip the search if makes no sense to the calling context.  */
 	if (!search)
-		return 0;
+		goto cleanup;
 
 	/* find commit which merges them */
-	parent_count = find_first_merges(opt->repo, path, commit_a, commit_b,
+	parent_count = find_first_merges(&subrepo, path, commit_a, commit_b,
 					 &merges);
 	switch (parent_count) {
 	case 0:
@@ -1626,7 +1643,7 @@
 		break;
 
 	case 1:
-		format_commit(&sb, 4,
+		format_commit(&sb, 4, &subrepo,
 			      (struct commit *)merges.objects[0].item);
 		path_msg(opt, path, 0,
 			 _("Failed to merge submodule %s, but a possible merge "
@@ -1643,7 +1660,7 @@
 		break;
 	default:
 		for (i = 0; i < merges.nr; i++)
-			format_commit(&sb, 4,
+			format_commit(&sb, 4, &subrepo,
 				      (struct commit *)merges.objects[i].item);
 		path_msg(opt, path, 0,
 			 _("Failed to merge submodule %s, but multiple "
@@ -1652,7 +1669,9 @@
 	}
 
 	object_array_clear(&merges);
-	return 0;
+cleanup:
+	repo_clear(&subrepo);
+	return ret;
 }
 
 static void initialize_attr_index(struct merge_options *opt)
@@ -2293,12 +2312,17 @@
 	VERIFY_CI(ci);
 
 	/* Find parent directories missing from opt->priv->paths */
-	cur_path = new_path;
+	cur_path = mem_pool_strdup(&opt->priv->pool, new_path);
+	free((char*)new_path);
+	new_path = (char *)cur_path;
+
 	while (1) {
 		/* Find the parent directory of cur_path */
 		char *last_slash = strrchr(cur_path, '/');
 		if (last_slash) {
-			parent_name = xstrndup(cur_path, last_slash - cur_path);
+			parent_name = mem_pool_strndup(&opt->priv->pool,
+						       cur_path,
+						       last_slash - cur_path);
 		} else {
 			parent_name = opt->priv->toplevel_dir;
 			break;
@@ -2307,7 +2331,6 @@
 		/* Look it up in opt->priv->paths */
 		entry = strmap_get_entry(&opt->priv->paths, parent_name);
 		if (entry) {
-			free((char*)parent_name);
 			parent_name = entry->key; /* reuse known pointer */
 			break;
 		}
@@ -2334,13 +2357,6 @@
 		parent_name = cur_dir;
 	}
 
-	/*
-	 * We are removing old_path from opt->priv->paths.  old_path also will
-	 * eventually need to be freed, but it may still be used by e.g.
-	 * ci->pathnames.  So, store it in another string-list for now.
-	 */
-	string_list_append(&opt->priv->paths_to_free, old_path);
-
 	assert(ci->filemask == 2 || ci->filemask == 4);
 	assert(ci->dirmask == 0);
 	strmap_remove(&opt->priv->paths, old_path, 0);
@@ -2374,7 +2390,6 @@
 		new_ci->stages[index].mode = ci->stages[index].mode;
 		oidcpy(&new_ci->stages[index].oid, &ci->stages[index].oid);
 
-		free(ci);
 		ci = new_ci;
 	}
 
@@ -2802,10 +2817,23 @@
 		if (!new_name)
 			new_name = old_name;
 
+		/*
+		 * cached_pairs has *copies* of old_name and new_name,
+		 * because it has to persist across merges.  Since
+		 * pool_alloc_filespec() will just re-use the existing
+		 * filenames, which will also get re-used by
+		 * opt->priv->paths if they become renames, and then
+		 * get freed at the end of the merge, that would leave
+		 * the copy in cached_pairs dangling.  Avoid this by
+		 * making a copy here.
+		 */
+		old_name = mem_pool_strdup(&opt->priv->pool, old_name);
+		new_name = mem_pool_strdup(&opt->priv->pool, new_name);
+
 		/* We don't care about oid/mode, only filenames and status */
-		one = alloc_filespec(old_name);
-		two = alloc_filespec(new_name);
-		diff_queue(pairs, one, two);
+		one = pool_alloc_filespec(&opt->priv->pool, old_name);
+		two = pool_alloc_filespec(&opt->priv->pool, new_name);
+		pool_diff_queue(&opt->priv->pool, pairs, one, two);
 		pairs->queue[pairs->nr-1]->status = entry->value ? 'R' : 'D';
 	}
 }
@@ -2913,6 +2941,7 @@
 	diff_queued_diff = renames->pairs[side_index];
 	trace2_region_enter("diff", "diffcore_rename", opt->repo);
 	diffcore_rename_extended(&diff_opts,
+				 &opt->priv->pool,
 				 &renames->relevant_sources[side_index],
 				 &renames->dirs_removed[side_index],
 				 &renames->dir_rename_count[side_index],
@@ -2963,7 +2992,7 @@
 
 		if (p->status != 'A' && p->status != 'R') {
 			possibly_cache_new_pair(renames, p, side_index, NULL);
-			diff_free_filepair(p);
+			pool_diff_free_filepair(&opt->priv->pool, p);
 			continue;
 		}
 
@@ -2976,7 +3005,7 @@
 
 		possibly_cache_new_pair(renames, p, side_index, new_path);
 		if (p->status != 'R' && !new_path) {
-			diff_free_filepair(p);
+			pool_diff_free_filepair(&opt->priv->pool, p);
 			continue;
 		}
 
@@ -3094,7 +3123,7 @@
 		side_pairs = &renames->pairs[s];
 		for (i = 0; i < side_pairs->nr; ++i) {
 			struct diff_filepair *p = side_pairs->queue[i];
-			diff_free_filepair(p);
+			pool_diff_free_filepair(&opt->priv->pool, p);
 		}
 	}
 
@@ -3107,7 +3136,8 @@
 	if (combined.nr) {
 		int i;
 		for (i = 0; i < combined.nr; i++)
-			diff_free_filepair(combined.queue[i]);
+			pool_diff_free_filepair(&opt->priv->pool,
+						combined.queue[i]);
 		free(combined.queue);
 	}
 
@@ -3581,7 +3611,8 @@
 		 * the directory to remain here, so we need to move this
 		 * path to some new location.
 		 */
-		CALLOC_ARRAY(new_ci, 1);
+		new_ci = mem_pool_calloc(&opt->priv->pool, 1, sizeof(*new_ci));
+
 		/* We don't really want new_ci->merged.result copied, but it'll
 		 * be overwritten below so it doesn't matter.  We also don't
 		 * want any directory mode/oid values copied, but we'll zero
@@ -3673,7 +3704,8 @@
 			const char *a_path = NULL, *b_path = NULL;
 			int rename_a = 0, rename_b = 0;
 
-			new_ci = xmalloc(sizeof(*new_ci));
+			new_ci = mem_pool_alloc(&opt->priv->pool,
+						sizeof(*new_ci));
 
 			if (S_ISREG(a_mode))
 				rename_a = 1;
@@ -3742,17 +3774,8 @@
 				b_path = path;
 			strmap_put(&opt->priv->paths, b_path, new_ci);
 
-			if (rename_a && rename_b) {
+			if (rename_a && rename_b)
 				strmap_remove(&opt->priv->paths, path, 0);
-				/*
-				 * We removed path from opt->priv->paths.  path
-				 * will also eventually need to be freed, but
-				 * it may still be used by e.g.  ci->pathnames.
-				 * So, store it in another string-list for now.
-				 */
-				string_list_append(&opt->priv->paths_to_free,
-						   path);
-			}
 
 			/*
 			 * Do special handling for b_path since process_entry()
@@ -4029,11 +4052,7 @@
 	unpack_opts.quiet = 0; /* FIXME: sequencer might want quiet? */
 	unpack_opts.verbose_update = (opt->verbosity > 2);
 	unpack_opts.fn = twoway_merge;
-	if (1/* FIXME: opts->overwrite_ignore*/) {
-		CALLOC_ARRAY(unpack_opts.dir, 1);
-		unpack_opts.dir->flags |= DIR_SHOW_IGNORED;
-		setup_standard_excludes(unpack_opts.dir);
-	}
+	unpack_opts.preserve_ignored = 0; /* FIXME: !opts->overwrite_ignore */
 	parse_tree(prev);
 	init_tree_desc(&trees[0], prev->buffer, prev->size);
 	parse_tree(next);
@@ -4041,8 +4060,6 @@
 
 	ret = unpack_trees(2, trees, &unpack_opts);
 	clear_unpack_trees_porcelain(&unpack_opts);
-	dir_clear(unpack_opts.dir);
-	FREE_AND_NULL(unpack_opts.dir);
 	return ret;
 }
 
@@ -4058,6 +4075,21 @@
 	if (strmap_empty(&opt->priv->conflicted))
 		return 0;
 
+	/*
+	 * We are in a conflicted state. These conflicts might be inside
+	 * sparse-directory entries, so check if any entries are outside
+	 * of the sparse-checkout cone preemptively.
+	 *
+	 * We set original_cache_nr below, but that might change if
+	 * index_name_pos() calls ask for paths within sparse directories.
+	 */
+	strmap_for_each_entry(&opt->priv->conflicted, &iter, e) {
+		if (!path_in_sparse_checkout(e->key, index)) {
+			ensure_full_index(index);
+			break;
+		}
+	}
+
 	/* If any entries have skip_worktree set, we'll have to check 'em out */
 	state.force = 1;
 	state.quiet = 1;
@@ -4293,6 +4325,7 @@
 {
 	struct rename_info *renames;
 	int i;
+	struct mem_pool *pool = NULL;
 
 	/* Sanity checks on opt */
 	trace2_region_enter("merge", "sanity checks", opt->repo);
@@ -4358,9 +4391,11 @@
 
 	/* Initialization of various renames fields */
 	renames = &opt->priv->renames;
+	mem_pool_init(&opt->priv->pool, 0);
+	pool = &opt->priv->pool;
 	for (i = MERGE_SIDE1; i <= MERGE_SIDE2; i++) {
 		strintmap_init_with_options(&renames->dirs_removed[i],
-					    NOT_RELEVANT, NULL, 0);
+					    NOT_RELEVANT, pool, 0);
 		strmap_init_with_options(&renames->dir_rename_count[i],
 					 NULL, 1);
 		strmap_init_with_options(&renames->dir_renames[i],
@@ -4374,7 +4409,7 @@
 		 */
 		strintmap_init_with_options(&renames->relevant_sources[i],
 					    -1 /* explicitly invalid */,
-					    NULL, 0);
+					    pool, 0);
 		strmap_init_with_options(&renames->cached_pairs[i],
 					 NULL, 1);
 		strset_init_with_options(&renames->cached_irrelevant[i],
@@ -4384,9 +4419,9 @@
 	}
 	for (i = MERGE_SIDE1; i <= MERGE_SIDE2; i++) {
 		strintmap_init_with_options(&renames->deferred[i].possible_trivial_merges,
-					    0, NULL, 0);
+					    0, pool, 0);
 		strset_init_with_options(&renames->deferred[i].target_dirs,
-					 NULL, 1);
+					 pool, 1);
 		renames->deferred[i].trivial_merges_okay = 1; /* 1 == maybe */
 	}
 
@@ -4394,14 +4429,13 @@
 	 * Although we initialize opt->priv->paths with strdup_strings=0,
 	 * that's just to avoid making yet another copy of an allocated
 	 * string.  Putting the entry into paths means we are taking
-	 * ownership, so we will later free it.  paths_to_free is similar.
+	 * ownership, so we will later free it.
 	 *
 	 * In contrast, conflicted just has a subset of keys from paths, so
 	 * we don't want to free those (it'd be a duplicate free).
 	 */
-	strmap_init_with_options(&opt->priv->paths, NULL, 0);
-	strmap_init_with_options(&opt->priv->conflicted, NULL, 0);
-	string_list_init_nodup(&opt->priv->paths_to_free);
+	strmap_init_with_options(&opt->priv->paths, pool, 0);
+	strmap_init_with_options(&opt->priv->conflicted, pool, 0);
 
 	/*
 	 * keys & strbufs in output will sometimes need to outlive "paths",
diff --git a/merge-recursive.c b/merge-recursive.c
index 3355d50..d945779 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -24,6 +24,7 @@
 #include "repository.h"
 #include "revision.h"
 #include "string-list.h"
+#include "submodule-config.h"
 #include "submodule.h"
 #include "tag.h"
 #include "tree-walk.h"
@@ -55,10 +56,7 @@
 	a = container_of(eptr, const struct path_hashmap_entry, e);
 	b = container_of(entry_or_key, const struct path_hashmap_entry, e);
 
-	if (ignore_case)
-		return strcasecmp(a->path, key ? key : b->path);
-	else
-		return strcmp(a->path, key ? key : b->path);
+	return fspathcmp(a->path, key ? key : b->path);
 }
 
 /*
@@ -336,7 +334,9 @@
 		flush_output(opt);
 }
 
-static void output_commit_title(struct merge_options *opt, struct commit *commit)
+static void repo_output_commit_title(struct merge_options *opt,
+				     struct repository *repo,
+				     struct commit *commit)
 {
 	struct merge_remote_desc *desc;
 
@@ -345,23 +345,29 @@
 	if (desc)
 		strbuf_addf(&opt->obuf, "virtual %s\n", desc->name);
 	else {
-		strbuf_add_unique_abbrev(&opt->obuf, &commit->object.oid,
-					 DEFAULT_ABBREV);
+		strbuf_repo_add_unique_abbrev(&opt->obuf, repo,
+					      &commit->object.oid,
+					      DEFAULT_ABBREV);
 		strbuf_addch(&opt->obuf, ' ');
-		if (parse_commit(commit) != 0)
+		if (repo_parse_commit(repo, commit) != 0)
 			strbuf_addstr(&opt->obuf, _("(bad commit)\n"));
 		else {
 			const char *title;
-			const char *msg = get_commit_buffer(commit, NULL);
+			const char *msg = repo_get_commit_buffer(repo, commit, NULL);
 			int len = find_commit_subject(msg, &title);
 			if (len)
 				strbuf_addf(&opt->obuf, "%.*s\n", len, title);
-			unuse_commit_buffer(commit, msg);
+			repo_unuse_commit_buffer(repo, commit, msg);
 		}
 	}
 	flush_output(opt);
 }
 
+static void output_commit_title(struct merge_options *opt, struct commit *commit)
+{
+	repo_output_commit_title(opt, the_repository, commit);
+}
+
 static int add_cacheinfo(struct merge_options *opt,
 			 const struct diff_filespec *blob,
 			 const char *path, int stage, int refresh, int options)
@@ -411,8 +417,11 @@
 	memset(&opt->priv->unpack_opts, 0, sizeof(opt->priv->unpack_opts));
 	if (opt->priv->call_depth)
 		opt->priv->unpack_opts.index_only = 1;
-	else
+	else {
 		opt->priv->unpack_opts.update = 1;
+		/* FIXME: should only do this if !overwrite_ignore */
+		opt->priv->unpack_opts.preserve_ignored = 0;
+	}
 	opt->priv->unpack_opts.merge = 1;
 	opt->priv->unpack_opts.head_idx = 2;
 	opt->priv->unpack_opts.fn = threeway_merge;
@@ -1113,7 +1122,6 @@
 	xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
 		  oid_to_hex(&a->object.oid));
 	repo_init_revisions(repo, &revs, NULL);
-	rev_opts.submodule = path;
 	/* FIXME: can't handle linked worktrees in submodules yet */
 	revs.single_worktree = path != NULL;
 	setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);
@@ -1123,7 +1131,7 @@
 		die("revision walk setup failed");
 	while ((commit = get_revision(&revs)) != NULL) {
 		struct object *o = &(commit->object);
-		if (in_merge_bases(b, commit))
+		if (repo_in_merge_bases(repo, b, commit))
 			add_object_array(o, NULL, &merges);
 	}
 	reset_revision_walk();
@@ -1138,7 +1146,7 @@
 		contains_another = 0;
 		for (j = 0; j < merges.nr; j++) {
 			struct commit *m2 = (struct commit *) merges.objects[j].item;
-			if (i != j && in_merge_bases(m2, m1)) {
+			if (i != j && repo_in_merge_bases(repo, m2, m1)) {
 				contains_another = 1;
 				break;
 			}
@@ -1152,14 +1160,14 @@
 	return result->nr;
 }
 
-static void print_commit(struct commit *commit)
+static void print_commit(struct repository *repo, struct commit *commit)
 {
 	struct strbuf sb = STRBUF_INIT;
 	struct pretty_print_context ctx = {0};
 	ctx.date_mode.type = DATE_NORMAL;
 	/* FIXME: Merge this with output_commit_title() */
 	assert(!merge_remote_util(commit));
-	format_commit_message(commit, " %h: %m %s", &sb, &ctx);
+	repo_format_commit_message(repo, commit, " %h: %m %s", &sb, &ctx);
 	fprintf(stderr, "%s\n", sb.buf);
 	strbuf_release(&sb);
 }
@@ -1174,6 +1182,8 @@
 			   const struct object_id *base, const struct object_id *a,
 			   const struct object_id *b)
 {
+	struct repository subrepo;
+	int ret = 0;
 	struct commit *commit_base, *commit_a, *commit_b;
 	int parent_count;
 	struct object_array merges;
@@ -1197,49 +1207,51 @@
 	if (is_null_oid(b))
 		return 0;
 
-	if (add_submodule_odb(path)) {
+	if (repo_submodule_init(&subrepo, opt->repo, path, null_oid())) {
 		output(opt, 1, _("Failed to merge submodule %s (not checked out)"), path);
 		return 0;
 	}
 
-	if (!(commit_base = lookup_commit_reference(opt->repo, base)) ||
-	    !(commit_a = lookup_commit_reference(opt->repo, a)) ||
-	    !(commit_b = lookup_commit_reference(opt->repo, b))) {
+	if (!(commit_base = lookup_commit_reference(&subrepo, base)) ||
+	    !(commit_a = lookup_commit_reference(&subrepo, a)) ||
+	    !(commit_b = lookup_commit_reference(&subrepo, b))) {
 		output(opt, 1, _("Failed to merge submodule %s (commits not present)"), path);
-		return 0;
+		goto cleanup;
 	}
 
 	/* check whether both changes are forward */
-	if (!in_merge_bases(commit_base, commit_a) ||
-	    !in_merge_bases(commit_base, commit_b)) {
+	if (!repo_in_merge_bases(&subrepo, commit_base, commit_a) ||
+	    !repo_in_merge_bases(&subrepo, commit_base, commit_b)) {
 		output(opt, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
-		return 0;
+		goto cleanup;
 	}
 
 	/* Case #1: a is contained in b or vice versa */
-	if (in_merge_bases(commit_a, commit_b)) {
+	if (repo_in_merge_bases(&subrepo, commit_a, commit_b)) {
 		oidcpy(result, b);
 		if (show(opt, 3)) {
 			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
-			output_commit_title(opt, commit_b);
+			repo_output_commit_title(opt, &subrepo, commit_b);
 		} else if (show(opt, 2))
 			output(opt, 2, _("Fast-forwarding submodule %s"), path);
 		else
 			; /* no output */
 
-		return 1;
+		ret = 1;
+		goto cleanup;
 	}
-	if (in_merge_bases(commit_b, commit_a)) {
+	if (repo_in_merge_bases(&subrepo, commit_b, commit_a)) {
 		oidcpy(result, a);
 		if (show(opt, 3)) {
 			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
-			output_commit_title(opt, commit_a);
+			repo_output_commit_title(opt, &subrepo, commit_a);
 		} else if (show(opt, 2))
 			output(opt, 2, _("Fast-forwarding submodule %s"), path);
 		else
 			; /* no output */
 
-		return 1;
+		ret = 1;
+		goto cleanup;
 	}
 
 	/*
@@ -1251,10 +1263,10 @@
 
 	/* Skip the search if makes no sense to the calling context.  */
 	if (!search)
-		return 0;
+		goto cleanup;
 
 	/* find commit which merges them */
-	parent_count = find_first_merges(opt->repo, &merges, path,
+	parent_count = find_first_merges(&subrepo, &merges, path,
 					 commit_a, commit_b);
 	switch (parent_count) {
 	case 0:
@@ -1264,7 +1276,7 @@
 	case 1:
 		output(opt, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
 		output(opt, 2, _("Found a possible merge resolution for the submodule:\n"));
-		print_commit((struct commit *) merges.objects[0].item);
+		print_commit(&subrepo, (struct commit *) merges.objects[0].item);
 		output(opt, 2, _(
 		       "If this is correct simply add it to the index "
 		       "for example\n"
@@ -1277,11 +1289,13 @@
 	default:
 		output(opt, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
 		for (i = 0; i < merges.nr; i++)
-			print_commit((struct commit *) merges.objects[i].item);
+			print_commit(&subrepo, (struct commit *) merges.objects[i].item);
 	}
 
 	object_array_clear(&merges);
-	return 0;
+cleanup:
+	repo_clear(&subrepo);
+	return ret;
 }
 
 static int merge_mode_and_contents(struct merge_options *opt,
@@ -3750,6 +3764,9 @@
 	assert(opt->ancestor == NULL ||
 	       !strcmp(opt->ancestor, "constructed merge base"));
 
+	prepare_repo_settings(opt->repo);
+	opt->repo->settings.command_requires_full_index = 1;
+
 	if (merge_start(opt, repo_get_commit_tree(opt->repo, h1)))
 		return -1;
 	clean = merge_recursive_internal(opt, h1, h2, merge_bases, result);
diff --git a/merge.c b/merge.c
index 6e73688..2382ff6 100644
--- a/merge.c
+++ b/merge.c
@@ -53,7 +53,6 @@
 	struct unpack_trees_options opts;
 	struct tree_desc t[MAX_UNPACK_TREES];
 	int i, nr_trees = 0;
-	struct dir_struct dir = DIR_INIT;
 	struct lock_file lock_file = LOCK_INIT;
 
 	refresh_index(r->index, REFRESH_QUIET, NULL, NULL, NULL);
@@ -80,11 +79,7 @@
 	}
 
 	memset(&opts, 0, sizeof(opts));
-	if (overwrite_ignore) {
-		dir.flags |= DIR_SHOW_IGNORED;
-		setup_standard_excludes(&dir);
-		opts.dir = &dir;
-	}
+	opts.preserve_ignored = !overwrite_ignore;
 
 	opts.head_idx = 1;
 	opts.src_index = r->index;
@@ -101,7 +96,6 @@
 		clear_unpack_trees_porcelain(&opts);
 		return -1;
 	}
-	dir_clear(&dir);
 	clear_unpack_trees_porcelain(&opts);
 
 	if (write_locked_index(r->index, &lock_file, COMMIT_LOCK))
diff --git a/mergesort.c b/mergesort.c
index e5fdf2e..6216835 100644
--- a/mergesort.c
+++ b/mergesort.c
@@ -1,73 +1,84 @@
 #include "cache.h"
 #include "mergesort.h"
 
-struct mergesort_sublist {
-	void *ptr;
-	unsigned long len;
-};
-
-static void *get_nth_next(void *list, unsigned long n,
-			  void *(*get_next_fn)(const void *))
+/* 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 *))
 {
-	while (n-- && list)
-		list = get_next_fn(list);
-	return list;
+	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);
+	}
 }
 
-static void *pop_item(struct mergesort_sublist *l,
-		      void *(*get_next_fn)(const void *))
-{
-	void *p = l->ptr;
-	l->ptr = get_next_fn(l->ptr);
-	l->len = l->ptr ? (l->len - 1) : 0;
-	return p;
-}
-
+/*
+ * 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 *))
 {
-	unsigned long l;
+	void *ranks[bitsizeof(void *)];
+	size_t n = 0;
+	int i;
 
-	if (!list)
-		return NULL;
-	for (l = 1; ; l *= 2) {
-		void *curr;
-		struct mergesort_sublist p, q;
+	while (list) {
+		void *next = get_next_fn(list);
+		if (next)
+			set_next_fn(list, NULL);
+		for (i = 0; n & (1 << i); i++)
+			list = llist_merge(ranks[i], list, get_next_fn,
+					   set_next_fn, compare_fn);
+		n++;
+		ranks[i] = list;
+		list = next;
+	}
 
-		p.ptr = list;
-		q.ptr = get_nth_next(p.ptr, l, get_next_fn);
-		if (!q.ptr)
-			break;
-		p.len = q.len = l;
-
-		if (compare_fn(p.ptr, q.ptr) > 0)
-			list = curr = pop_item(&q, get_next_fn);
+	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 = curr = pop_item(&p, get_next_fn);
-
-		while (p.ptr) {
-			while (p.len || q.len) {
-				void *prev = curr;
-
-				if (!p.len)
-					curr = pop_item(&q, get_next_fn);
-				else if (!q.len)
-					curr = pop_item(&p, get_next_fn);
-				else if (compare_fn(p.ptr, q.ptr) > 0)
-					curr = pop_item(&q, get_next_fn);
-				else
-					curr = pop_item(&p, get_next_fn);
-				set_next_fn(prev, curr);
-			}
-			p.ptr = q.ptr;
-			p.len = l;
-			q.ptr = get_nth_next(p.ptr, l, get_next_fn);
-			q.len = q.ptr ? l : 0;
-
-		}
-		set_next_fn(curr, NULL);
+			list = ranks[i];
 	}
 	return list;
 }
diff --git a/mergetools/xxdiff b/mergetools/xxdiff
index ce5b8e9..d5ce467 100644
--- a/mergetools/xxdiff
+++ b/mergetools/xxdiff
@@ -3,6 +3,13 @@
 		-R 'Accel.Search: "Ctrl+F"' \
 		-R 'Accel.SearchForward: "Ctrl+G"' \
 		"$LOCAL" "$REMOTE"
+
+	# xxdiff can segfault on binary files which are often uninteresting.
+	# Do not allow segfaults to stop us from continuing on to the next file.
+	if test $? = 128
+	then
+		return 1
+	fi
 }
 
 merge_cmd () {
diff --git a/midx.c b/midx.c
index 321c6fd..8433086 100644
--- a/midx.c
+++ b/midx.c
@@ -13,6 +13,10 @@
 #include "repository.h"
 #include "chunk-format.h"
 #include "pack.h"
+#include "pack-bitmap.h"
+#include "refs.h"
+#include "revision.h"
+#include "list-objects.h"
 
 #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
 #define MIDX_VERSION 1
@@ -48,12 +52,12 @@
 	}
 }
 
-static const unsigned char *get_midx_checksum(struct multi_pack_index *m)
+const unsigned char *get_midx_checksum(struct multi_pack_index *m)
 {
 	return m->data + m->data_len - the_hash_algo->rawsz;
 }
 
-static char *get_midx_filename(const char *object_dir)
+char *get_midx_filename(const char *object_dir)
 {
 	return xstrfmt("%s/pack/multi-pack-index", object_dir);
 }
@@ -195,6 +199,8 @@
 	if (!m)
 		return;
 
+	close_midx(m->next);
+
 	munmap((unsigned char *)m->data, m->data_len);
 
 	for (i = 0; i < m->num_packs; i++) {
@@ -203,6 +209,7 @@
 	}
 	FREE_AND_NULL(m->packs);
 	FREE_AND_NULL(m->pack_names);
+	free(m);
 }
 
 int prepare_midx_pack(struct repository *r, struct multi_pack_index *m, uint32_t pack_int_id)
@@ -276,14 +283,18 @@
 			(off_t)pos * MIDX_CHUNK_OFFSET_WIDTH);
 }
 
-static int nth_midxed_pack_entry(struct repository *r,
-				 struct multi_pack_index *m,
-				 struct pack_entry *e,
-				 uint32_t pos)
+int fill_midx_entry(struct repository * r,
+		    const struct object_id *oid,
+		    struct pack_entry *e,
+		    struct multi_pack_index *m)
 {
+	uint32_t pos;
 	uint32_t pack_int_id;
 	struct packed_git *p;
 
+	if (!bsearch_midx(oid, m, &pos))
+		return 0;
+
 	if (pos >= m->num_objects)
 		return 0;
 
@@ -303,15 +314,9 @@
 	if (!is_pack_valid(p))
 		return 0;
 
-	if (p->num_bad_objects) {
-		uint32_t i;
-		struct object_id oid;
-		nth_midxed_object_oid(&oid, m, pos);
-		for (i = 0; i < p->num_bad_objects; i++)
-			if (hasheq(oid.hash,
-				   p->bad_object_sha1 + the_hash_algo->rawsz * i))
-				return 0;
-	}
+	if (oidset_size(&p->bad_objects) &&
+	    oidset_contains(&p->bad_objects, oid))
+		return 0;
 
 	e->offset = nth_midxed_offset(m, pos);
 	e->p = p;
@@ -319,19 +324,6 @@
 	return 1;
 }
 
-int fill_midx_entry(struct repository * r,
-		    const struct object_id *oid,
-		    struct pack_entry *e,
-		    struct multi_pack_index *m)
-{
-	uint32_t pos;
-
-	if (!bsearch_midx(oid, m, &pos))
-		return 0;
-
-	return nth_midxed_pack_entry(r, m, e, pos);
-}
-
 /* Match "foo.idx" against either "foo.pack" _or_ "foo.idx". */
 static int cmp_idx_or_pack_name(const char *idx_or_pack_name,
 				const char *idx_name)
@@ -468,6 +460,8 @@
 	uint32_t num_large_offsets;
 
 	int preferred_pack_idx;
+
+	struct string_list *to_include;
 };
 
 static void add_pack_to_midx(const char *full_path, size_t full_path_len,
@@ -477,8 +471,26 @@
 
 	if (ends_with(file_name, ".idx")) {
 		display_progress(ctx->progress, ++ctx->pack_paths_checked);
+		/*
+		 * Note that at most one of ctx->m and ctx->to_include are set,
+		 * so we are testing midx_contains_pack() and
+		 * string_list_has_string() independently (guarded by the
+		 * appropriate NULL checks).
+		 *
+		 * We could support passing to_include while reusing an existing
+		 * MIDX, but don't currently since the reuse process drags
+		 * forward all packs from an existing MIDX (without checking
+		 * whether or not they appear in the to_include list).
+		 *
+		 * If we added support for that, these next two conditional
+		 * should be performed independently (likely checking
+		 * to_include before the existing MIDX).
+		 */
 		if (ctx->m && midx_contains_pack(ctx->m, file_name))
 			return;
+		else if (ctx->to_include &&
+			 !string_list_has_string(ctx->to_include, file_name))
+			return;
 
 		ALLOC_GROW(ctx->info, ctx->nr + 1, ctx->alloc);
 
@@ -882,7 +894,7 @@
 	strbuf_release(&buf);
 }
 
-static void clear_midx_files_ext(struct repository *r, const char *ext,
+static void clear_midx_files_ext(const char *object_dir, const char *ext,
 				 unsigned char *keep_hash);
 
 static int midx_checksum_valid(struct multi_pack_index *m)
@@ -890,9 +902,232 @@
 	return hashfile_checksum_valid(m->data, m->data_len);
 }
 
-static int write_midx_internal(const char *object_dir, struct multi_pack_index *m,
+static void prepare_midx_packing_data(struct packing_data *pdata,
+				      struct write_midx_context *ctx)
+{
+	uint32_t i;
+
+	memset(pdata, 0, sizeof(struct packing_data));
+	prepare_packing_data(the_repository, pdata);
+
+	for (i = 0; i < ctx->entries_nr; i++) {
+		struct pack_midx_entry *from = &ctx->entries[ctx->pack_order[i]];
+		struct object_entry *to = packlist_alloc(pdata, &from->oid);
+
+		oe_set_in_pack(pdata, to,
+			       ctx->info[ctx->pack_perm[from->pack_int_id]].p);
+	}
+}
+
+static int add_ref_to_pending(const char *refname,
+			      const struct object_id *oid,
+			      int flag, void *cb_data)
+{
+	struct rev_info *revs = (struct rev_info*)cb_data;
+	struct object *object;
+
+	if ((flag & REF_ISSYMREF) && (flag & REF_ISBROKEN)) {
+		warning("symbolic ref is dangling: %s", refname);
+		return 0;
+	}
+
+	object = parse_object_or_die(oid, refname);
+	if (object->type != OBJ_COMMIT)
+		return 0;
+
+	add_pending_object(revs, object, "");
+	if (bitmap_is_preferred_refname(revs->repo, refname))
+		object->flags |= NEEDS_BITMAP;
+	return 0;
+}
+
+struct bitmap_commit_cb {
+	struct commit **commits;
+	size_t commits_nr, commits_alloc;
+
+	struct write_midx_context *ctx;
+};
+
+static const struct object_id *bitmap_oid_access(size_t index,
+						 const void *_entries)
+{
+	const struct pack_midx_entry *entries = _entries;
+	return &entries[index].oid;
+}
+
+static void bitmap_show_commit(struct commit *commit, void *_data)
+{
+	struct bitmap_commit_cb *data = _data;
+	int pos = oid_pos(&commit->object.oid, data->ctx->entries,
+			  data->ctx->entries_nr,
+			  bitmap_oid_access);
+	if (pos < 0)
+		return;
+
+	ALLOC_GROW(data->commits, data->commits_nr + 1, data->commits_alloc);
+	data->commits[data->commits_nr++] = commit;
+}
+
+static int read_refs_snapshot(const char *refs_snapshot,
+			      struct rev_info *revs)
+{
+	struct strbuf buf = STRBUF_INIT;
+	struct object_id oid;
+	FILE *f = xfopen(refs_snapshot, "r");
+
+	while (strbuf_getline(&buf, f) != EOF) {
+		struct object *object;
+		int preferred = 0;
+		char *hex = buf.buf;
+		const char *end = NULL;
+
+		if (buf.len && *buf.buf == '+') {
+			preferred = 1;
+			hex = &buf.buf[1];
+		}
+
+		if (parse_oid_hex(hex, &oid, &end) < 0)
+			die(_("could not parse line: %s"), buf.buf);
+		if (*end)
+			die(_("malformed line: %s"), buf.buf);
+
+		object = parse_object_or_die(&oid, NULL);
+		if (preferred)
+			object->flags |= NEEDS_BITMAP;
+
+		add_pending_object(revs, object, "");
+	}
+
+	fclose(f);
+	strbuf_release(&buf);
+	return 0;
+}
+
+static struct commit **find_commits_for_midx_bitmap(uint32_t *indexed_commits_nr_p,
+						    const char *refs_snapshot,
+						    struct write_midx_context *ctx)
+{
+	struct rev_info revs;
+	struct bitmap_commit_cb cb = {0};
+
+	cb.ctx = ctx;
+
+	repo_init_revisions(the_repository, &revs, NULL);
+	if (refs_snapshot) {
+		read_refs_snapshot(refs_snapshot, &revs);
+	} else {
+		setup_revisions(0, NULL, &revs, NULL);
+		for_each_ref(add_ref_to_pending, &revs);
+	}
+
+	/*
+	 * Skipping promisor objects here is intentional, since it only excludes
+	 * them from the list of reachable commits that we want to select from
+	 * when computing the selection of MIDX'd commits to receive bitmaps.
+	 *
+	 * Reachability bitmaps do require that their objects be closed under
+	 * reachability, but fetching any objects missing from promisors at this
+	 * point is too late. But, if one of those objects can be reached from
+	 * an another object that is included in the bitmap, then we will
+	 * complain later that we don't have reachability closure (and fail
+	 * appropriately).
+	 */
+	fetch_if_missing = 0;
+	revs.exclude_promisor_objects = 1;
+
+	if (prepare_revision_walk(&revs))
+		die(_("revision walk setup failed"));
+
+	traverse_commit_list(&revs, bitmap_show_commit, NULL, &cb);
+	if (indexed_commits_nr_p)
+		*indexed_commits_nr_p = cb.commits_nr;
+
+	return cb.commits;
+}
+
+static int write_midx_bitmap(char *midx_name, unsigned char *midx_hash,
+			     struct write_midx_context *ctx,
+			     const char *refs_snapshot,
+			     unsigned flags)
+{
+	struct packing_data pdata;
+	struct pack_idx_entry **index;
+	struct commit **commits = NULL;
+	uint32_t i, commits_nr;
+	uint16_t options = 0;
+	char *bitmap_name = xstrfmt("%s-%s.bitmap", midx_name, hash_to_hex(midx_hash));
+	int ret;
+
+	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);
+
+	/*
+	 * 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;
+
+	bitmap_writer_show_progress(flags & MIDX_PROGRESS);
+	bitmap_writer_build_type_index(&pdata, index, pdata.nr_objects);
+
+	/*
+	 * bitmap_writer_finish expects objects in lex order, but pack_order
+	 * gives us exactly that. use it directly instead of re-sorting the
+	 * array.
+	 *
+	 * This changes the order of objects in 'index' between
+	 * bitmap_writer_build_type_index and bitmap_writer_finish.
+	 *
+	 * The same re-ordering takes place in the single-pack bitmap code via
+	 * write_idx_file(), which is called by finish_tmp_packfile(), which
+	 * 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;
+
+	bitmap_writer_select_commits(commits, commits_nr, -1);
+	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);
+
+cleanup:
+	free(index);
+	free(bitmap_name);
+	return ret;
+}
+
+static struct multi_pack_index *lookup_multi_pack_index(struct repository *r,
+							const char *object_dir)
+{
+	struct multi_pack_index *cur;
+
+	/* Ensure the given object_dir is local, or a known alternate. */
+	find_odb(r, object_dir);
+
+	for (cur = get_multi_pack_index(r); cur; cur = cur->next) {
+		if (!strcmp(object_dir, cur->object_dir))
+			return cur;
+	}
+
+	return NULL;
+}
+
+static int write_midx_internal(const char *object_dir,
+			       struct string_list *packs_to_include,
 			       struct string_list *packs_to_drop,
 			       const char *preferred_pack_name,
+			       const char *refs_snapshot,
 			       unsigned flags)
 {
 	char *midx_name;
@@ -911,10 +1146,14 @@
 		die_errno(_("unable to create leading directories of %s"),
 			  midx_name);
 
-	if (m)
-		ctx.m = m;
-	else
-		ctx.m = load_multi_pack_index(object_dir, 1);
+	if (!packs_to_include) {
+		/*
+		 * Only reference an existing MIDX when not filtering which
+		 * packs to include, since all packs and objects are copied
+		 * blindly from an existing MIDX if one is present.
+		 */
+		ctx.m = lookup_multi_pack_index(the_repository, object_dir);
+	}
 
 	if (ctx.m && !midx_checksum_valid(ctx.m)) {
 		warning(_("ignoring existing multi-pack-index; checksum mismatch"));
@@ -932,8 +1171,27 @@
 
 			ctx.info[ctx.nr].orig_pack_int_id = i;
 			ctx.info[ctx.nr].pack_name = xstrdup(ctx.m->pack_names[i]);
-			ctx.info[ctx.nr].p = NULL;
+			ctx.info[ctx.nr].p = ctx.m->packs[i];
 			ctx.info[ctx.nr].expired = 0;
+
+			if (flags & MIDX_WRITE_REV_INDEX) {
+				/*
+				 * If generating a reverse index, need to have
+				 * packed_git's loaded to compare their
+				 * mtimes and object count.
+				 */
+				if (prepare_midx_pack(the_repository, ctx.m, i)) {
+					error(_("could not load pack"));
+					result = 1;
+					goto cleanup;
+				}
+
+				if (open_pack_index(ctx.m->packs[i]))
+					die(_("could not open index for %s"),
+					    ctx.m->packs[i]->pack_name);
+				ctx.info[ctx.nr].p = ctx.m->packs[i];
+			}
+
 			ctx.nr++;
 		}
 	}
@@ -944,21 +1202,95 @@
 	else
 		ctx.progress = NULL;
 
+	ctx.to_include = packs_to_include;
+
 	for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &ctx);
 	stop_progress(&ctx.progress);
 
-	if (ctx.m && ctx.nr == ctx.m->num_packs && !packs_to_drop)
-		goto cleanup;
+	if ((ctx.m && ctx.nr == ctx.m->num_packs) &&
+	    !(packs_to_include || packs_to_drop)) {
+		struct bitmap_index *bitmap_git;
+		int bitmap_exists;
+		int want_bitmap = flags & MIDX_WRITE_BITMAP;
 
-	ctx.preferred_pack_idx = -1;
+		bitmap_git = prepare_midx_bitmap_git(ctx.m);
+		bitmap_exists = bitmap_git && bitmap_is_midx(bitmap_git);
+		free_bitmap_index(bitmap_git);
+
+		if (bitmap_exists || !want_bitmap) {
+			/*
+			 * The correct MIDX already exists, and so does a
+			 * corresponding bitmap (or one wasn't requested).
+			 */
+			if (!want_bitmap)
+				clear_midx_files_ext(object_dir, ".bitmap",
+						     NULL);
+			goto cleanup;
+		}
+	}
+
 	if (preferred_pack_name) {
+		int found = 0;
 		for (i = 0; i < ctx.nr; i++) {
 			if (!cmp_idx_or_pack_name(preferred_pack_name,
 						  ctx.info[i].pack_name)) {
 				ctx.preferred_pack_idx = i;
+				found = 1;
 				break;
 			}
 		}
+
+		if (!found)
+			warning(_("unknown preferred pack: '%s'"),
+				preferred_pack_name);
+	} else if (ctx.nr &&
+		   (flags & (MIDX_WRITE_REV_INDEX | MIDX_WRITE_BITMAP))) {
+		struct packed_git *oldest = ctx.info[ctx.preferred_pack_idx].p;
+		ctx.preferred_pack_idx = 0;
+
+		if (packs_to_drop && packs_to_drop->nr)
+			BUG("cannot write a MIDX bitmap during expiration");
+
+		/*
+		 * set a preferred pack when writing a bitmap to ensure that
+		 * the pack from which the first object is selected in pseudo
+		 * pack-order has all of its objects selected from that pack
+		 * (and not another pack containing a duplicate)
+		 */
+		for (i = 1; i < ctx.nr; i++) {
+			struct packed_git *p = ctx.info[i].p;
+
+			if (!oldest->num_objects || p->mtime < oldest->mtime) {
+				oldest = p;
+				ctx.preferred_pack_idx = i;
+			}
+		}
+
+		if (!oldest->num_objects) {
+			/*
+			 * If all packs are empty; unset the preferred index.
+			 * This is acceptable since there will be no duplicate
+			 * objects to resolve, so the preferred value doesn't
+			 * matter.
+			 */
+			ctx.preferred_pack_idx = -1;
+		}
+	} else {
+		/*
+		 * otherwise don't mark any pack as preferred to avoid
+		 * interfering with expiration logic below
+		 */
+		ctx.preferred_pack_idx = -1;
+	}
+
+	if (ctx.preferred_pack_idx > -1) {
+		struct packed_git *preferred = ctx.info[ctx.preferred_pack_idx].p;
+		if (!preferred->num_objects) {
+			error(_("cannot select preferred pack %s with no objects"),
+			      preferred->pack_name);
+			result = 1;
+			goto cleanup;
+		}
 	}
 
 	ctx.entries = get_sorted_entries(ctx.m, ctx.info, ctx.nr, &ctx.entries_nr,
@@ -1029,11 +1361,7 @@
 						      ctx.info, ctx.nr,
 						      sizeof(*ctx.info),
 						      idx_or_pack_name_cmp);
-
-		if (!preferred)
-			warning(_("unknown preferred pack: '%s'"),
-				preferred_pack_name);
-		else {
+		if (preferred) {
 			uint32_t perm = ctx.pack_perm[preferred->orig_pack_int_id];
 			if (perm == PACK_EXPIRED)
 				warning(_("preferred pack '%s' is expired"),
@@ -1048,9 +1376,6 @@
 	hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR);
 	f = hashfd(get_lock_file_fd(&lk), get_lock_file_path(&lk));
 
-	if (ctx.m)
-		close_midx(ctx.m);
-
 	if (ctx.nr - dropped_packs == 0) {
 		error(_("no pack files to index."));
 		result = 1;
@@ -1081,14 +1406,28 @@
 	finalize_hashfile(f, midx_hash, CSUM_FSYNC | CSUM_HASH_IN_STREAM);
 	free_chunkfile(cf);
 
-	if (flags & MIDX_WRITE_REV_INDEX)
+	if (flags & (MIDX_WRITE_REV_INDEX | MIDX_WRITE_BITMAP))
 		ctx.pack_order = midx_pack_order(&ctx);
 
 	if (flags & MIDX_WRITE_REV_INDEX)
 		write_midx_reverse_index(midx_name, midx_hash, &ctx);
-	clear_midx_files_ext(the_repository, ".rev", midx_hash);
+	if (flags & MIDX_WRITE_BITMAP) {
+		if (write_midx_bitmap(midx_name, midx_hash, &ctx,
+				      refs_snapshot, flags) < 0) {
+			error(_("could not write multi-pack bitmap"));
+			result = 1;
+			goto cleanup;
+		}
+	}
 
-	commit_lock_file(&lk);
+	if (ctx.m)
+		close_object_store(the_repository->objects);
+
+	if (commit_lock_file(&lk) < 0)
+		die_errno(_("could not write multi-pack-index"));
+
+	clear_midx_files_ext(object_dir, ".bitmap", midx_hash);
+	clear_midx_files_ext(object_dir, ".rev", midx_hash);
 
 cleanup:
 	for (i = 0; i < ctx.nr; i++) {
@@ -1104,15 +1443,27 @@
 	free(ctx.pack_perm);
 	free(ctx.pack_order);
 	free(midx_name);
+
 	return result;
 }
 
 int write_midx_file(const char *object_dir,
 		    const char *preferred_pack_name,
+		    const char *refs_snapshot,
 		    unsigned flags)
 {
 	return write_midx_internal(object_dir, NULL, NULL, preferred_pack_name,
-				   flags);
+				   refs_snapshot, flags);
+}
+
+int write_midx_file_only(const char *object_dir,
+			 struct string_list *packs_to_include,
+			 const char *preferred_pack_name,
+			 const char *refs_snapshot,
+			 unsigned flags)
+{
+	return write_midx_internal(object_dir, packs_to_include, NULL,
+				   preferred_pack_name, refs_snapshot, flags);
 }
 
 struct clear_midx_data {
@@ -1135,7 +1486,7 @@
 		die_errno(_("failed to remove %s"), full_path);
 }
 
-static void clear_midx_files_ext(struct repository *r, const char *ext,
+static void clear_midx_files_ext(const char *object_dir, const char *ext,
 				 unsigned char *keep_hash)
 {
 	struct clear_midx_data data;
@@ -1146,7 +1497,7 @@
 				    hash_to_hex(keep_hash), ext);
 	data.ext = ext;
 
-	for_each_file_in_pack_dir(r->objects->odb->path,
+	for_each_file_in_pack_dir(object_dir,
 				  clear_midx_file_ext,
 				  &data);
 
@@ -1165,7 +1516,8 @@
 	if (remove_path(midx))
 		die(_("failed to clear multi-pack-index at %s"), midx);
 
-	clear_midx_files_ext(r, ".rev", NULL);
+	clear_midx_files_ext(r->objects->odb->path, ".bitmap", NULL);
+	clear_midx_files_ext(r->objects->odb->path, ".rev", NULL);
 
 	free(midx);
 }
@@ -1345,7 +1697,7 @@
 {
 	uint32_t i, *count, result = 0;
 	struct string_list packs_to_drop = STRING_LIST_INIT_DUP;
-	struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
+	struct multi_pack_index *m = lookup_multi_pack_index(r, object_dir);
 	struct progress *progress = NULL;
 
 	if (!m)
@@ -1391,9 +1743,10 @@
 	free(count);
 
 	if (packs_to_drop.nr)
-		result = write_midx_internal(object_dir, m, &packs_to_drop, NULL, flags);
+		result = write_midx_internal(object_dir, NULL, &packs_to_drop, NULL, NULL, flags);
 
 	string_list_clear(&packs_to_drop, 0);
+
 	return result;
 }
 
@@ -1509,7 +1862,7 @@
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	FILE *cmd_in;
 	struct strbuf base_name = STRBUF_INIT;
-	struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
+	struct multi_pack_index *m = lookup_multi_pack_index(r, object_dir);
 
 	/*
 	 * When updating the default for these configuration
@@ -1580,12 +1933,9 @@
 		goto cleanup;
 	}
 
-	result = write_midx_internal(object_dir, m, NULL, NULL, flags);
-	m = NULL;
+	result = write_midx_internal(object_dir, NULL, NULL, NULL, NULL, flags);
 
 cleanup:
-	if (m)
-		close_midx(m);
 	free(include_pack);
 	return result;
 }
diff --git a/midx.h b/midx.h
index 8684cf0..6e32297 100644
--- a/midx.h
+++ b/midx.h
@@ -2,12 +2,15 @@
 #define MIDX_H
 
 #include "repository.h"
+#include "string-list.h"
 
 struct object_id;
 struct pack_entry;
 struct repository;
 
 #define GIT_TEST_MULTI_PACK_INDEX "GIT_TEST_MULTI_PACK_INDEX"
+#define GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP \
+	"GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP"
 
 struct multi_pack_index {
 	struct multi_pack_index *next;
@@ -41,7 +44,11 @@
 
 #define MIDX_PROGRESS     (1 << 0)
 #define MIDX_WRITE_REV_INDEX (1 << 1)
+#define MIDX_WRITE_BITMAP (1 << 2)
+#define MIDX_WRITE_BITMAP_HASH_CACHE (1 << 3)
 
+const unsigned char *get_midx_checksum(struct multi_pack_index *m);
+char *get_midx_filename(const char *object_dir);
 char *get_midx_rev_filename(struct multi_pack_index *m);
 
 struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local);
@@ -56,7 +63,19 @@
 int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name);
 int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local);
 
-int write_midx_file(const char *object_dir, const char *preferred_pack_name, unsigned flags);
+/*
+ * Variant of write_midx_file which writes a MIDX containing only the packs
+ * specified in packs_to_include.
+ */
+int write_midx_file(const char *object_dir,
+		    const char *preferred_pack_name,
+		    const char *refs_snapshot,
+		    unsigned flags);
+int write_midx_file_only(const char *object_dir,
+			 struct string_list *packs_to_include,
+			 const char *preferred_pack_name,
+			 const char *refs_snapshot,
+			 unsigned flags);
 void clear_midx_file(struct repository *r);
 int verify_midx_file(struct repository *r, const char *object_dir, unsigned flags);
 int expire_midx_packs(struct repository *r, const char *object_dir, unsigned flags);
diff --git a/notes-merge.c b/notes-merge.c
index 46c1f7c..b4a3a90 100644
--- a/notes-merge.c
+++ b/notes-merge.c
@@ -273,7 +273,7 @@
 		 */
 		if (file_exists(git_path(NOTES_MERGE_WORKTREE)) &&
 		    !is_empty_dir(git_path(NOTES_MERGE_WORKTREE))) {
-			if (advice_resolve_conflict)
+			if (advice_enabled(ADVICE_RESOLVE_CONFLICT))
 				die(_("You have not concluded your previous "
 				    "notes merge (%s exists).\nPlease, use "
 				    "'git notes merge --commit' or 'git notes "
diff --git a/object-file.c b/object-file.c
index a8be899..02b7970 100644
--- a/object-file.c
+++ b/object-file.c
@@ -32,6 +32,7 @@
 #include "packfile.h"
 #include "object-store.h"
 #include "promisor-remote.h"
+#include "submodule.h"
 
 /* The maximum size for an object header. */
 #define MAX_HEADER_LEN 32
@@ -414,74 +415,6 @@
 	return result;
 }
 
-int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
-{
-	/*
-	 * The number of times we will try to remove empty directories
-	 * in the way of path. This is only 1 because if another
-	 * process is racily creating directories that conflict with
-	 * us, we don't want to fight against them.
-	 */
-	int remove_directories_remaining = 1;
-
-	/*
-	 * The number of times that we will try to create the
-	 * directories containing path. We are willing to attempt this
-	 * more than once, because another process could be trying to
-	 * clean up empty directories at the same time as we are
-	 * trying to create them.
-	 */
-	int create_directories_remaining = 3;
-
-	/* A scratch copy of path, filled lazily if we need it: */
-	struct strbuf path_copy = STRBUF_INIT;
-
-	int ret, save_errno;
-
-	/* Sanity check: */
-	assert(*path);
-
-retry_fn:
-	ret = fn(path, cb);
-	save_errno = errno;
-	if (!ret)
-		goto out;
-
-	if (errno == EISDIR && remove_directories_remaining-- > 0) {
-		/*
-		 * A directory is in the way. Maybe it is empty; try
-		 * to remove it:
-		 */
-		if (!path_copy.len)
-			strbuf_addstr(&path_copy, path);
-
-		if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
-			goto retry_fn;
-	} else if (errno == ENOENT && create_directories_remaining-- > 0) {
-		/*
-		 * Maybe the containing directory didn't exist, or
-		 * maybe it was just deleted by a process that is
-		 * racing with us to clean up empty directories. Try
-		 * to create it:
-		 */
-		enum scld_error scld_result;
-
-		if (!path_copy.len)
-			strbuf_addstr(&path_copy, path);
-
-		do {
-			scld_result = safe_create_leading_directories(path_copy.buf);
-			if (scld_result == SCLD_OK)
-				goto retry_fn;
-		} while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
-	}
-
-out:
-	strbuf_release(&path_copy);
-	errno = save_errno;
-	return ret;
-}
-
 static void fill_loose_path(struct strbuf *buf, const struct object_id *oid)
 {
 	int i;
@@ -820,6 +753,27 @@
 	return ref_git;
 }
 
+struct object_directory *find_odb(struct repository *r, const char *obj_dir)
+{
+	struct object_directory *odb;
+	char *obj_dir_real = real_pathdup(obj_dir, 1);
+	struct strbuf odb_path_real = STRBUF_INIT;
+
+	prepare_alt_odb(r);
+	for (odb = r->objects->odb; odb; odb = odb->next) {
+		strbuf_realpath(&odb_path_real, odb->path, 1);
+		if (!strcmp(obj_dir_real, odb_path_real.buf))
+			break;
+	}
+
+	free(obj_dir_real);
+	strbuf_release(&odb_path_real);
+
+	if (!odb)
+		die(_("could not find object directory matching %s"), obj_dir);
+	return odb;
+}
+
 static void fill_alternate_refs_command(struct child_process *cmd,
 					const char *repo_path)
 {
@@ -1062,9 +1016,11 @@
  * the streaming interface and rehash it to do the same.
  */
 int check_object_signature(struct repository *r, const struct object_id *oid,
-			   void *map, unsigned long size, const char *type)
+			   void *map, unsigned long size, const char *type,
+			   struct object_id *real_oidp)
 {
-	struct object_id real_oid;
+	struct object_id tmp;
+	struct object_id *real_oid = real_oidp ? real_oidp : &tmp;
 	enum object_type obj_type;
 	struct git_istream *st;
 	git_hash_ctx c;
@@ -1072,8 +1028,8 @@
 	int hdrlen;
 
 	if (map) {
-		hash_object_file(r->hash_algo, map, size, type, &real_oid);
-		return !oideq(oid, &real_oid) ? -1 : 0;
+		hash_object_file(r->hash_algo, map, size, type, real_oid);
+		return !oideq(oid, real_oid) ? -1 : 0;
 	}
 
 	st = open_istream(r, oid, &obj_type, &size, NULL);
@@ -1098,9 +1054,9 @@
 			break;
 		r->hash_algo->update_fn(&c, buf, readlen);
 	}
-	r->hash_algo->final_oid_fn(&real_oid, &c);
+	r->hash_algo->final_oid_fn(real_oid, &c);
 	close_istream(st);
-	return !oideq(oid, &real_oid) ? -1 : 0;
+	return !oideq(oid, real_oid) ? -1 : 0;
 }
 
 int git_open_cloexec(const char *name, int flags)
@@ -1233,11 +1189,14 @@
 	return map_loose_object_1(r, NULL, oid, size);
 }
 
-static int unpack_loose_short_header(git_zstream *stream,
-				     unsigned char *map, unsigned long mapsize,
-				     void *buffer, unsigned long bufsiz)
+enum unpack_loose_header_result unpack_loose_header(git_zstream *stream,
+						    unsigned char *map,
+						    unsigned long mapsize,
+						    void *buffer,
+						    unsigned long bufsiz,
+						    struct strbuf *header)
 {
-	int ret;
+	int status;
 
 	/* Get the data stream */
 	memset(stream, 0, sizeof(*stream));
@@ -1248,43 +1207,24 @@
 
 	git_inflate_init(stream);
 	obj_read_unlock();
-	ret = git_inflate(stream, 0);
+	status = git_inflate(stream, 0);
 	obj_read_lock();
-
-	return ret;
-}
-
-int unpack_loose_header(git_zstream *stream,
-			unsigned char *map, unsigned long mapsize,
-			void *buffer, unsigned long bufsiz)
-{
-	int status = unpack_loose_short_header(stream, map, mapsize,
-					       buffer, bufsiz);
-
 	if (status < Z_OK)
-		return status;
-
-	/* Make sure we have the terminating NUL */
-	if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
-		return -1;
-	return 0;
-}
-
-static int unpack_loose_header_to_strbuf(git_zstream *stream, unsigned char *map,
-					 unsigned long mapsize, void *buffer,
-					 unsigned long bufsiz, struct strbuf *header)
-{
-	int status;
-
-	status = unpack_loose_short_header(stream, map, mapsize, buffer, bufsiz);
-	if (status < Z_OK)
-		return -1;
+		return ULHR_BAD;
 
 	/*
 	 * Check if entire header is unpacked in the first iteration.
 	 */
 	if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
-		return 0;
+		return ULHR_OK;
+
+	/*
+	 * We have a header longer than MAX_HEADER_LEN. The "header"
+	 * here is only non-NULL when we run "cat-file
+	 * --allow-unknown-type".
+	 */
+	if (!header)
+		return ULHR_TOO_LONG;
 
 	/*
 	 * buffer[0..bufsiz] was not large enough.  Copy the partial
@@ -1305,7 +1245,7 @@
 		stream->next_out = buffer;
 		stream->avail_out = bufsiz;
 	} while (status != Z_STREAM_END);
-	return -1;
+	return ULHR_TOO_LONG;
 }
 
 static void *unpack_loose_rest(git_zstream *stream,
@@ -1363,8 +1303,7 @@
  * too permissive for what we want to check. So do an anal
  * object header parse by hand.
  */
-static int parse_loose_header_extended(const char *hdr, struct object_info *oi,
-				       unsigned int flags)
+int parse_loose_header(const char *hdr, struct object_info *oi)
 {
 	const char *type_buf = hdr;
 	unsigned long size;
@@ -1386,15 +1325,6 @@
 	type = type_from_string_gently(type_buf, type_len, 1);
 	if (oi->type_name)
 		strbuf_add(oi->type_name, type_buf, type_len);
-	/*
-	 * Set type to 0 if its an unknown object and
-	 * we're obtaining the type using '--allow-unknown-type'
-	 * option.
-	 */
-	if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
-		type = 0;
-	else if (type < 0)
-		die(_("invalid object type"));
 	if (oi->typep)
 		*oi->typep = type;
 
@@ -1421,15 +1351,14 @@
 	/*
 	 * The length must be followed by a zero byte
 	 */
-	return *hdr ? -1 : type;
-}
+	if (*hdr)
+		return -1;
 
-int parse_loose_header(const char *hdr, unsigned long *sizep)
-{
-	struct object_info oi = OBJECT_INFO_INIT;
-
-	oi.sizep = sizep;
-	return parse_loose_header_extended(hdr, &oi, 0);
+	/*
+	 * The format is valid, but the type may still be bogus. The
+	 * Caller needs to check its oi->typep.
+	 */
+	return 0;
 }
 
 static int loose_object_info(struct repository *r,
@@ -1443,6 +1372,8 @@
 	char hdr[MAX_HEADER_LEN];
 	struct strbuf hdrbuf = STRBUF_INIT;
 	unsigned long size_scratch;
+	enum object_type type_scratch;
+	int allow_unknown = flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE;
 
 	if (oi->delta_base_oid)
 		oidclr(oi->delta_base_oid);
@@ -1473,43 +1404,48 @@
 
 	if (!oi->sizep)
 		oi->sizep = &size_scratch;
+	if (!oi->typep)
+		oi->typep = &type_scratch;
 
 	if (oi->disk_sizep)
 		*oi->disk_sizep = mapsize;
-	if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
-		if (unpack_loose_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
-			status = error(_("unable to unpack %s header with --allow-unknown-type"),
-				       oid_to_hex(oid));
-	} else if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
+
+	switch (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr),
+				    allow_unknown ? &hdrbuf : NULL)) {
+	case ULHR_OK:
+		if (parse_loose_header(hdrbuf.len ? hdrbuf.buf : hdr, oi) < 0)
+			status = error(_("unable to parse %s header"), oid_to_hex(oid));
+		else if (!allow_unknown && *oi->typep < 0)
+			die(_("invalid object type"));
+
+		if (!oi->contentp)
+			break;
+		*oi->contentp = unpack_loose_rest(&stream, hdr, *oi->sizep, oid);
+		if (*oi->contentp)
+			goto cleanup;
+
+		status = -1;
+		break;
+	case ULHR_BAD:
 		status = error(_("unable to unpack %s header"),
 			       oid_to_hex(oid));
-	if (status < 0)
-		; /* Do nothing */
-	else if (hdrbuf.len) {
-		if ((status = parse_loose_header_extended(hdrbuf.buf, oi, flags)) < 0)
-			status = error(_("unable to parse %s header with --allow-unknown-type"),
-				       oid_to_hex(oid));
-	} else if ((status = parse_loose_header_extended(hdr, oi, flags)) < 0)
-		status = error(_("unable to parse %s header"), oid_to_hex(oid));
+		break;
+	case ULHR_TOO_LONG:
+		status = error(_("header for %s too long, exceeds %d bytes"),
+			       oid_to_hex(oid), MAX_HEADER_LEN);
+		break;
+	}
 
-	if (status >= 0 && oi->contentp) {
-		*oi->contentp = unpack_loose_rest(&stream, hdr,
-						  *oi->sizep, oid);
-		if (!*oi->contentp) {
-			git_inflate_end(&stream);
-			status = -1;
-		}
-	} else
-		git_inflate_end(&stream);
-
+	git_inflate_end(&stream);
+cleanup:
 	munmap(map, mapsize);
-	if (status && oi->typep)
-		*oi->typep = status;
 	if (oi->sizep == &size_scratch)
 		oi->sizep = NULL;
 	strbuf_release(&hdrbuf);
+	if (oi->typep == &type_scratch)
+		oi->typep = NULL;
 	oi->whence = OI_LOOSE;
-	return (status < 0) ? status : 0;
+	return status;
 }
 
 int obj_read_use_lock = 0;
@@ -1592,6 +1528,17 @@
 				break;
 		}
 
+		/*
+		 * If r is the_repository, this might be an attempt at
+		 * accessing a submodule object as if it were in the_repository
+		 * (having called add_submodule_odb() on that submodule's ODB).
+		 * If any such ODBs exist, register them and try again.
+		 */
+		if (r == the_repository &&
+		    register_all_submodule_odb_as_alternates())
+			/* We added some alternates; retry */
+			continue;
+
 		/* Check if it is a missing object */
 		if (fetch_if_missing && repo_has_promisor_remote(r) &&
 		    !already_retried &&
@@ -1616,7 +1563,7 @@
 		return 0;
 	rtype = packed_object_info(r, e.p, e.offset, oi);
 	if (rtype < 0) {
-		mark_bad_packed_object(e.p, real->hash);
+		mark_bad_packed_object(e.p, real);
 		return do_oid_object_info_extended(r, real, oi, 0);
 	} else if (oi->whence == OI_PACKED) {
 		oi->u.packed.offset = e.offset;
@@ -1725,7 +1672,7 @@
 		die(_("loose object %s (stored in %s) is corrupt"),
 		    oid_to_hex(repl), path);
 
-	if ((p = has_packed_and_bad(r, repl->hash)) != NULL)
+	if ((p = has_packed_and_bad(r, repl)) != NULL)
 		die(_("packed object %s (stored in %s) is corrupt"),
 		    oid_to_hex(repl), p->pack_name);
 	obj_read_unlock();
@@ -1915,7 +1862,7 @@
 
 static int write_loose_object(const struct object_id *oid, char *hdr,
 			      int hdrlen, const void *buf, unsigned long len,
-			      time_t mtime)
+			      time_t mtime, unsigned flags)
 {
 	int fd, ret;
 	unsigned char compressed[4096];
@@ -1929,7 +1876,9 @@
 
 	fd = create_tmpfile(&tmp_file, filename.buf);
 	if (fd < 0) {
-		if (errno == EACCES)
+		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"));
@@ -1979,7 +1928,8 @@
 		struct utimbuf utb;
 		utb.actime = mtime;
 		utb.modtime = mtime;
-		if (utime(tmp_file.buf, &utb) < 0)
+		if (utime(tmp_file.buf, &utb) < 0 &&
+		    !(flags & HASH_SILENT))
 			warning_errno(_("failed utime() on %s"), tmp_file.buf);
 	}
 
@@ -2004,8 +1954,9 @@
 	return 1;
 }
 
-int write_object_file(const void *buf, unsigned long len, const char *type,
-		      struct object_id *oid)
+int write_object_file_flags(const void *buf, unsigned long len,
+			    const char *type, struct object_id *oid,
+			    unsigned flags)
 {
 	char hdr[MAX_HEADER_LEN];
 	int hdrlen = sizeof(hdr);
@@ -2017,7 +1968,7 @@
 				  &hdrlen);
 	if (freshen_packed_object(oid) || freshen_loose_object(oid))
 		return 0;
-	return write_loose_object(oid, hdr, hdrlen, buf, len, 0);
+	return write_loose_object(oid, hdr, hdrlen, buf, len, 0, flags);
 }
 
 int hash_object_file_literally(const void *buf, unsigned long len,
@@ -2037,7 +1988,7 @@
 		goto cleanup;
 	if (freshen_packed_object(oid) || freshen_loose_object(oid))
 		goto cleanup;
-	status = write_loose_object(oid, header, hdrlen, buf, len, 0);
+	status = write_loose_object(oid, header, hdrlen, buf, len, 0, 0);
 
 cleanup:
 	free(header);
@@ -2059,7 +2010,7 @@
 	if (!buf)
 		return error(_("cannot read object for %s"), oid_to_hex(oid));
 	hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %"PRIuMAX , type_name(type), (uintmax_t)len) + 1;
-	ret = write_loose_object(oid, hdr, hdrlen, buf, len, mtime);
+	ret = write_loose_object(oid, hdr, hdrlen, buf, len, mtime, 0);
 	free(buf);
 
 	return ret;
@@ -2566,17 +2517,16 @@
 
 int read_loose_object(const char *path,
 		      const struct object_id *expected_oid,
-		      enum object_type *type,
-		      unsigned long *size,
-		      void **contents)
+		      struct object_id *real_oid,
+		      void **contents,
+		      struct object_info *oi)
 {
 	int ret = -1;
 	void *map = NULL;
 	unsigned long mapsize;
 	git_zstream stream;
 	char hdr[MAX_HEADER_LEN];
-
-	*contents = NULL;
+	unsigned long *size = oi->sizep;
 
 	map = map_loose_object_1(the_repository, path, NULL, &mapsize);
 	if (!map) {
@@ -2584,19 +2534,19 @@
 		goto out;
 	}
 
-	if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
+	if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr),
+				NULL) < 0) {
 		error(_("unable to unpack header of %s"), path);
 		goto out;
 	}
 
-	*type = parse_loose_header(hdr, size);
-	if (*type < 0) {
+	if (parse_loose_header(hdr, oi) < 0) {
 		error(_("unable to parse header of %s"), path);
 		git_inflate_end(&stream);
 		goto out;
 	}
 
-	if (*type == OBJ_BLOB && *size > big_file_threshold) {
+	if (*oi->typep == OBJ_BLOB && *size > big_file_threshold) {
 		if (check_stream_oid(&stream, hdr, *size, path, expected_oid) < 0)
 			goto out;
 	} else {
@@ -2607,10 +2557,7 @@
 			goto out;
 		}
 		if (check_object_signature(the_repository, expected_oid,
-					   *contents, *size,
-					   type_name(*type))) {
-			error(_("hash mismatch for %s (expected %s)"), path,
-			      oid_to_hex(expected_oid));
+					   *contents, *size, oi->type_name->buf, real_oid)) {
 			free(*contents);
 			goto out;
 		}
diff --git a/object-name.c b/object-name.c
index 3263c19..fdff460 100644
--- a/object-name.c
+++ b/object-name.c
@@ -806,7 +806,7 @@
 			refs_found = repo_dwim_ref(r, str, len, &tmp_oid, &real_ref, 0);
 			if (refs_found > 0) {
 				warning(warn_msg, len, str);
-				if (advice_object_name_warning)
+				if (advice_enabled(ADVICE_OBJECT_NAME_WARNING))
 					fprintf(stderr, "%s\n", _(object_name_msg));
 			}
 			free(real_ref);
diff --git a/object-store.h b/object-store.h
index d24915c..952efb6 100644
--- a/object-store.h
+++ b/object-store.h
@@ -10,6 +10,7 @@
 #include "khash.h"
 #include "dir.h"
 #include "oidtree.h"
+#include "oidset.h"
 
 struct object_directory {
 	struct object_directory *next;
@@ -38,6 +39,7 @@
 
 void prepare_alt_odb(struct repository *r);
 char *compute_alternate_path(const char *path, struct strbuf *err);
+struct object_directory *find_odb(struct repository *r, const char *obj_dir);
 typedef int alt_odb_fn(struct object_directory *, void *);
 int foreach_alt_odb(alt_odb_fn, void*);
 typedef void alternate_ref_fn(const struct object_id *oid, void *);
@@ -75,9 +77,8 @@
 	const void *index_data;
 	size_t index_size;
 	uint32_t num_objects;
-	uint32_t num_bad_objects;
 	uint32_t crc_offset;
-	unsigned char *bad_object_sha1;
+	struct oidset bad_objects;
 	int index_version;
 	time_t mtime;
 	int pack_fd;
@@ -222,8 +223,14 @@
 		     unsigned long len, const char *type,
 		     struct object_id *oid);
 
-int write_object_file(const void *buf, unsigned long len,
-		      const char *type, struct object_id *oid);
+int write_object_file_flags(const void *buf, unsigned long len,
+			    const char *type, struct object_id *oid,
+			    unsigned flags);
+static inline int write_object_file(const void *buf, unsigned long len,
+				    const char *type, struct object_id *oid)
+{
+	return write_object_file_flags(buf, len, type, oid, 0);
+}
 
 int hash_object_file_literally(const void *buf, unsigned long len,
 			       const char *type, struct object_id *oid,
@@ -244,6 +251,7 @@
 
 /*
  * Open the loose object at path, check its hash, and return the contents,
+ * use the "oi" argument to assert things about the object, or e.g. populate its
  * type, and size. If the object is a blob, then "contents" may return NULL,
  * to allow streaming of large blobs.
  *
@@ -251,9 +259,9 @@
  */
 int read_loose_object(const char *path,
 		      const struct object_id *expected_oid,
-		      enum object_type *type,
-		      unsigned long *size,
-		      void **contents);
+		      struct object_id *real_oid,
+		      void **contents,
+		      struct object_info *oi);
 
 /* Retry packed storage after checking packed and loose storage */
 #define HAS_OBJECT_RECHECK_PACKED 1
@@ -370,7 +378,7 @@
  * Initializer for a "struct object_info" that wants no items. You may
  * also memset() the memory to all-zeroes.
  */
-#define OBJECT_INFO_INIT {NULL}
+#define OBJECT_INFO_INIT { 0 }
 
 /* Invoke lookup_replace_object() on the given hash */
 #define OBJECT_INFO_LOOKUP_REPLACE 1
@@ -455,6 +463,12 @@
 	 * Visit objects within a pack in packfile order rather than .idx order
 	 */
 	FOR_EACH_OBJECT_PACK_ORDER = (1<<2),
+
+	/* Only iterate over packs that are not marked as kept in-core. */
+	FOR_EACH_OBJECT_SKIP_IN_CORE_KEPT_PACKS = (1<<3),
+
+	/* Only iterate over packs that do not have .keep files. */
+	FOR_EACH_OBJECT_SKIP_ON_DISK_KEPT_PACKS = (1<<4),
 };
 
 /*
diff --git a/object.c b/object.c
index 4e85955..23a24e6 100644
--- a/object.c
+++ b/object.c
@@ -279,7 +279,7 @@
 	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 (check_object_signature(r, repl, NULL, 0, NULL) < 0) {
+		if (check_object_signature(r, repl, NULL, 0, NULL, NULL) < 0) {
 			error(_("hash mismatch %s"), oid_to_hex(oid));
 			return NULL;
 		}
@@ -290,7 +290,7 @@
 	buffer = repo_read_object_file(r, oid, &type, &size);
 	if (buffer) {
 		if (check_object_signature(r, repl, buffer, size,
-					   type_name(type)) < 0) {
+					   type_name(type), NULL) < 0) {
 			free(buffer);
 			error(_("hash mismatch %s"), oid_to_hex(repl));
 			return NULL;
diff --git a/object.h b/object.h
index 3b38c9c..cb556ab 100644
--- a/object.h
+++ b/object.h
@@ -55,7 +55,7 @@
 	} *objects;
 };
 
-#define OBJECT_ARRAY_INIT { 0, 0, NULL }
+#define OBJECT_ARRAY_INIT { 0 }
 
 /*
  * object flag allocation:
@@ -75,7 +75,6 @@
  * builtin/fsck.c:           0--3
  * builtin/gc.c:             0
  * builtin/index-pack.c:                                     2021
- * builtin/pack-objects.c:                                   20
  * builtin/reflog.c:                   10--12
  * builtin/show-branch.c:    0-------------------------------------------26
  * builtin/unpack-objects.c:                                 2021
diff --git a/oid-array.h b/oid-array.h
index 72bca78..f60f9af 100644
--- a/oid-array.h
+++ b/oid-array.h
@@ -56,7 +56,7 @@
 	int sorted;
 };
 
-#define OID_ARRAY_INIT { NULL, 0, 0, 0 }
+#define OID_ARRAY_INIT { 0 }
 
 /**
  * Add an item to the set. The object ID will be placed at the end of the array
diff --git a/oidset.c b/oidset.c
index 5aac633..b36a2ba 100644
--- a/oidset.c
+++ b/oidset.c
@@ -36,11 +36,6 @@
 	oidset_init(set, 0);
 }
 
-int oidset_size(struct oidset *set)
-{
-	return kh_size(&set->set);
-}
-
 void oidset_parse_file(struct oidset *set, const char *path)
 {
 	oidset_parse_file_carefully(set, path, NULL, NULL);
diff --git a/oidset.h b/oidset.h
index 01f6560..ba4a5a2 100644
--- a/oidset.h
+++ b/oidset.h
@@ -57,7 +57,10 @@
 /**
  * Returns the number of oids in the set.
  */
-int oidset_size(struct oidset *set);
+static inline int oidset_size(const struct oidset *set)
+{
+	return kh_size(&set->set);
+}
 
 /**
  * Remove all entries from the oidset, freeing any resources associated with
diff --git a/pack-bitmap-write.c b/pack-bitmap-write.c
index 88d9e69..9c55c15 100644
--- a/pack-bitmap-write.c
+++ b/pack-bitmap-write.c
@@ -48,7 +48,7 @@
 }
 
 /**
- * Build the initial type index for the packfile
+ * Build the initial type index for the packfile or multi-pack-index
  */
 void bitmap_writer_build_type_index(struct packing_data *to_pack,
 				    struct pack_idx_entry **index,
@@ -125,15 +125,20 @@
 	writer.selected_nr++;
 }
 
-static uint32_t find_object_pos(const struct object_id *oid)
+static uint32_t find_object_pos(const struct object_id *oid, int *found)
 {
 	struct object_entry *entry = packlist_find(writer.to_pack, oid);
 
 	if (!entry) {
-		die("Failed to write bitmap index. Packfile doesn't have full closure "
+		if (found)
+			*found = 0;
+		warning("Failed to write bitmap index. Packfile doesn't have full closure "
 			"(object %s is missing)", oid_to_hex(oid));
+		return 0;
 	}
 
+	if (found)
+		*found = 1;
 	return oe_in_pack_pos(writer.to_pack, entry);
 }
 
@@ -331,9 +336,10 @@
 	bb->commits_nr = bb->commits_alloc = 0;
 }
 
-static void fill_bitmap_tree(struct bitmap *bitmap,
-			     struct tree *tree)
+static int fill_bitmap_tree(struct bitmap *bitmap,
+			    struct tree *tree)
 {
+	int found;
 	uint32_t pos;
 	struct tree_desc desc;
 	struct name_entry entry;
@@ -342,9 +348,11 @@
 	 * If our bit is already set, then there is nothing to do. Both this
 	 * tree and all of its children will be set.
 	 */
-	pos = find_object_pos(&tree->object.oid);
+	pos = find_object_pos(&tree->object.oid, &found);
+	if (!found)
+		return -1;
 	if (bitmap_get(bitmap, pos))
-		return;
+		return 0;
 	bitmap_set(bitmap, pos);
 
 	if (parse_tree(tree) < 0)
@@ -355,11 +363,15 @@
 	while (tree_entry(&desc, &entry)) {
 		switch (object_type(entry.mode)) {
 		case OBJ_TREE:
-			fill_bitmap_tree(bitmap,
-					 lookup_tree(the_repository, &entry.oid));
+			if (fill_bitmap_tree(bitmap,
+					     lookup_tree(the_repository, &entry.oid)) < 0)
+				return -1;
 			break;
 		case OBJ_BLOB:
-			bitmap_set(bitmap, find_object_pos(&entry.oid));
+			pos = find_object_pos(&entry.oid, &found);
+			if (!found)
+				return -1;
+			bitmap_set(bitmap, pos);
 			break;
 		default:
 			/* Gitlink, etc; not reachable */
@@ -368,15 +380,18 @@
 	}
 
 	free_tree_buffer(tree);
+	return 0;
 }
 
-static void fill_bitmap_commit(struct bb_commit *ent,
-			       struct commit *commit,
-			       struct prio_queue *queue,
-			       struct prio_queue *tree_queue,
-			       struct bitmap_index *old_bitmap,
-			       const uint32_t *mapping)
+static int fill_bitmap_commit(struct bb_commit *ent,
+			      struct commit *commit,
+			      struct prio_queue *queue,
+			      struct prio_queue *tree_queue,
+			      struct bitmap_index *old_bitmap,
+			      const uint32_t *mapping)
 {
+	int found;
+	uint32_t pos;
 	if (!ent->bitmap)
 		ent->bitmap = bitmap_new();
 
@@ -401,11 +416,16 @@
 		 * Mark ourselves and queue our tree. The commit
 		 * walk ensures we cover all parents.
 		 */
-		bitmap_set(ent->bitmap, find_object_pos(&c->object.oid));
+		pos = find_object_pos(&c->object.oid, &found);
+		if (!found)
+			return -1;
+		bitmap_set(ent->bitmap, pos);
 		prio_queue_put(tree_queue, get_commit_tree(c));
 
 		for (p = c->parents; p; p = p->next) {
-			int pos = find_object_pos(&p->item->object.oid);
+			pos = find_object_pos(&p->item->object.oid, &found);
+			if (!found)
+				return -1;
 			if (!bitmap_get(ent->bitmap, pos)) {
 				bitmap_set(ent->bitmap, pos);
 				prio_queue_put(queue, p->item);
@@ -413,8 +433,12 @@
 		}
 	}
 
-	while (tree_queue->nr)
-		fill_bitmap_tree(ent->bitmap, prio_queue_get(tree_queue));
+	while (tree_queue->nr) {
+		if (fill_bitmap_tree(ent->bitmap,
+				     prio_queue_get(tree_queue)) < 0)
+			return -1;
+	}
+	return 0;
 }
 
 static void store_selected(struct bb_commit *ent, struct commit *commit)
@@ -432,7 +456,7 @@
 	kh_value(writer.bitmaps, hash_pos) = stored;
 }
 
-void bitmap_writer_build(struct packing_data *to_pack)
+int bitmap_writer_build(struct packing_data *to_pack)
 {
 	struct bitmap_builder bb;
 	size_t i;
@@ -441,6 +465,7 @@
 	struct prio_queue tree_queue = { NULL };
 	struct bitmap_index *old_bitmap;
 	uint32_t *mapping;
+	int closed = 1; /* until proven otherwise */
 
 	writer.bitmaps = kh_init_oid_map();
 	writer.to_pack = to_pack;
@@ -463,8 +488,11 @@
 		struct commit *child;
 		int reused = 0;
 
-		fill_bitmap_commit(ent, commit, &queue, &tree_queue,
-				   old_bitmap, mapping);
+		if (fill_bitmap_commit(ent, commit, &queue, &tree_queue,
+				       old_bitmap, mapping) < 0) {
+			closed = 0;
+			break;
+		}
 
 		if (ent->selected) {
 			store_selected(ent, commit);
@@ -492,6 +520,7 @@
 	clear_prio_queue(&queue);
 	clear_prio_queue(&tree_queue);
 	bitmap_builder_clear(&bb);
+	free_bitmap_index(old_bitmap);
 	free(mapping);
 
 	trace2_region_leave("pack-bitmap-write", "building_bitmaps_total",
@@ -499,7 +528,9 @@
 
 	stop_progress(&writer.progress);
 
-	compute_xor_offsets();
+	if (closed)
+		compute_xor_offsets();
+	return closed ? 0 : -1;
 }
 
 /**
diff --git a/pack-bitmap.c b/pack-bitmap.c
index d999616..f47a0a7 100644
--- a/pack-bitmap.c
+++ b/pack-bitmap.c
@@ -13,6 +13,7 @@
 #include "repository.h"
 #include "object-store.h"
 #include "list-objects-filter-options.h"
+#include "midx.h"
 #include "config.h"
 
 /*
@@ -35,8 +36,15 @@
  * the active bitmap index is the largest one.
  */
 struct bitmap_index {
-	/* Packfile to which this bitmap index belongs to */
+	/*
+	 * The pack or multi-pack index (MIDX) that this bitmap index belongs
+	 * to.
+	 *
+	 * Exactly one of these must be non-NULL; this specifies the object
+	 * order used to interpret this bitmap.
+	 */
 	struct packed_git *pack;
+	struct multi_pack_index *midx;
 
 	/*
 	 * Mark the first `reuse_objects` in the packfile as reused:
@@ -71,6 +79,9 @@
 	/* If not NULL, this is a name-hash cache pointing into map. */
 	uint32_t *hashes;
 
+	/* The checksum of the packfile or MIDX; points into map. */
+	const unsigned char *checksum;
+
 	/*
 	 * Extended index.
 	 *
@@ -136,6 +147,13 @@
 	return b;
 }
 
+static uint32_t bitmap_num_objects(struct bitmap_index *index)
+{
+	if (index->midx)
+		return index->midx->num_objects;
+	return index->pack->num_objects;
+}
+
 static int load_bitmap_header(struct bitmap_index *index)
 {
 	struct bitmap_disk_header *header = (void *)index->map;
@@ -154,7 +172,7 @@
 	/* Parse known bitmap format options */
 	{
 		uint32_t flags = ntohs(header->options);
-		size_t cache_size = st_mult(index->pack->num_objects, sizeof(uint32_t));
+		size_t cache_size = st_mult(bitmap_num_objects(index), sizeof(uint32_t));
 		unsigned char *index_end = index->map + index->map_size - the_hash_algo->rawsz;
 
 		if ((flags & BITMAP_OPT_FULL_DAG) == 0)
@@ -170,6 +188,7 @@
 	}
 
 	index->entry_count = ntohl(header->entry_count);
+	index->checksum = header->checksum;
 	index->map_pos += header_size;
 	return 0;
 }
@@ -218,6 +237,15 @@
 
 #define MAX_XOR_OFFSET 160
 
+static int nth_bitmap_object_oid(struct bitmap_index *index,
+				 struct object_id *oid,
+				 uint32_t n)
+{
+	if (index->midx)
+		return nth_midxed_object_oid(oid, index->midx, n) ? 0 : -1;
+	return nth_packed_object_id(oid, index->pack, n);
+}
+
 static int load_bitmap_entries_v1(struct bitmap_index *index)
 {
 	uint32_t i;
@@ -237,7 +265,7 @@
 		xor_offset = read_u8(index->map, &index->map_pos);
 		flags = read_u8(index->map, &index->map_pos);
 
-		if (nth_packed_object_id(&oid, index->pack, commit_idx_pos) < 0)
+		if (nth_bitmap_object_oid(index, &oid, commit_idx_pos) < 0)
 			return error("corrupt ewah bitmap: commit index %u out of range",
 				     (unsigned)commit_idx_pos);
 
@@ -262,7 +290,14 @@
 	return 0;
 }
 
-static char *pack_bitmap_filename(struct packed_git *p)
+char *midx_bitmap_filename(struct multi_pack_index *midx)
+{
+	return xstrfmt("%s-%s.bitmap",
+		       get_midx_filename(midx->object_dir),
+		       hash_to_hex(get_midx_checksum(midx)));
+}
+
+char *pack_bitmap_filename(struct packed_git *p)
 {
 	size_t len;
 
@@ -271,6 +306,57 @@
 	return xstrfmt("%.*s.bitmap", (int)len, p->pack_name);
 }
 
+static int open_midx_bitmap_1(struct bitmap_index *bitmap_git,
+			      struct multi_pack_index *midx)
+{
+	struct stat st;
+	char *idx_name = midx_bitmap_filename(midx);
+	int fd = git_open(idx_name);
+
+	free(idx_name);
+
+	if (fd < 0)
+		return -1;
+
+	if (fstat(fd, &st)) {
+		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",
+			get_midx_filename(midx->object_dir));
+		close(fd);
+		return -1;
+	}
+
+	bitmap_git->midx = midx;
+	bitmap_git->map_size = xsize_t(st.st_size);
+	bitmap_git->map_pos = 0;
+	bitmap_git->map = xmmap(NULL, bitmap_git->map_size, PROT_READ,
+				MAP_PRIVATE, fd, 0);
+	close(fd);
+
+	if (load_bitmap_header(bitmap_git) < 0)
+		goto cleanup;
+
+	if (!hasheq(get_midx_checksum(bitmap_git->midx), bitmap_git->checksum))
+		goto cleanup;
+
+	if (load_midx_revindex(bitmap_git->midx) < 0) {
+		warning(_("multi-pack bitmap is missing required reverse index"));
+		goto cleanup;
+	}
+	return 0;
+
+cleanup:
+	munmap(bitmap_git->map, bitmap_git->map_size);
+	bitmap_git->map_size = 0;
+	bitmap_git->map = NULL;
+	return -1;
+}
+
 static int open_pack_bitmap_1(struct bitmap_index *bitmap_git, struct packed_git *packfile)
 {
 	int fd;
@@ -292,7 +378,8 @@
 		return -1;
 	}
 
-	if (bitmap_git->pack) {
+	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);
 		close(fd);
 		return -1;
@@ -319,13 +406,39 @@
 	return 0;
 }
 
-static int load_pack_bitmap(struct bitmap_index *bitmap_git)
+static int load_reverse_index(struct bitmap_index *bitmap_git)
+{
+	if (bitmap_is_midx(bitmap_git)) {
+		uint32_t i;
+		int ret;
+
+		/*
+		 * The multi-pack-index's .rev file is already loaded via
+		 * open_pack_bitmap_1().
+		 *
+		 * But we still need to open the individual pack .rev files,
+		 * since we will need to make use of them in pack-objects.
+		 */
+		for (i = 0; i < bitmap_git->midx->num_packs; i++) {
+			if (prepare_midx_pack(the_repository, bitmap_git->midx, i))
+				die(_("load_reverse_index: could not open pack"));
+			ret = load_pack_revindex(bitmap_git->midx->packs[i]);
+			if (ret)
+				return ret;
+		}
+		return 0;
+	}
+	return load_pack_revindex(bitmap_git->pack);
+}
+
+static int load_bitmap(struct bitmap_index *bitmap_git)
 {
 	assert(bitmap_git->map);
 
 	bitmap_git->bitmaps = kh_init_oid_map();
 	bitmap_git->ext_index.positions = kh_init_oid_pos();
-	if (load_pack_revindex(bitmap_git->pack))
+
+	if (load_reverse_index(bitmap_git))
 		goto failed;
 
 	if (!(bitmap_git->commits = read_bitmap_1(bitmap_git)) ||
@@ -369,11 +482,46 @@
 	return ret;
 }
 
+static int open_midx_bitmap(struct repository *r,
+			    struct bitmap_index *bitmap_git)
+{
+	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;
+	}
+	return -1;
+}
+
+static int open_bitmap(struct repository *r,
+		       struct bitmap_index *bitmap_git)
+{
+	assert(!bitmap_git->map);
+
+	if (!open_midx_bitmap(r, bitmap_git))
+		return 0;
+	return open_pack_bitmap(r, bitmap_git);
+}
+
 struct bitmap_index *prepare_bitmap_git(struct repository *r)
 {
 	struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
 
-	if (!open_pack_bitmap(r, bitmap_git) && !load_pack_bitmap(bitmap_git))
+	if (!open_bitmap(r, bitmap_git) && !load_bitmap(bitmap_git))
+		return bitmap_git;
+
+	free_bitmap_index(bitmap_git);
+	return NULL;
+}
+
+struct bitmap_index *prepare_midx_bitmap_git(struct multi_pack_index *midx)
+{
+	struct bitmap_index *bitmap_git = xcalloc(1, sizeof(*bitmap_git));
+
+	if (!open_midx_bitmap_1(bitmap_git, midx) && !load_bitmap(bitmap_git))
 		return bitmap_git;
 
 	free_bitmap_index(bitmap_git);
@@ -404,7 +552,7 @@
 
 	if (pos < kh_end(positions)) {
 		int bitmap_pos = kh_value(positions, pos);
-		return bitmap_pos + bitmap_git->pack->num_objects;
+		return bitmap_pos + bitmap_num_objects(bitmap_git);
 	}
 
 	return -1;
@@ -423,10 +571,26 @@
 	return pos;
 }
 
+static int bitmap_position_midx(struct bitmap_index *bitmap_git,
+				const struct object_id *oid)
+{
+	uint32_t want, got;
+	if (!bsearch_midx(oid, bitmap_git->midx, &want))
+		return -1;
+
+	if (midx_to_pack_pos(bitmap_git->midx, want, &got) < 0)
+		return -1;
+	return got;
+}
+
 static int bitmap_position(struct bitmap_index *bitmap_git,
 			   const struct object_id *oid)
 {
-	int pos = bitmap_position_packfile(bitmap_git, oid);
+	int pos;
+	if (bitmap_is_midx(bitmap_git))
+		pos = bitmap_position_midx(bitmap_git, oid);
+	else
+		pos = bitmap_position_packfile(bitmap_git, oid);
 	return (pos >= 0) ? pos : bitmap_position_extended(bitmap_git, oid);
 }
 
@@ -456,7 +620,7 @@
 		bitmap_pos = kh_value(eindex->positions, hash_pos);
 	}
 
-	return bitmap_pos + bitmap_git->pack->num_objects;
+	return bitmap_pos + bitmap_num_objects(bitmap_git);
 }
 
 struct bitmap_show_data {
@@ -673,7 +837,7 @@
 	for (i = 0; i < eindex->count; ++i) {
 		struct object *obj;
 
-		if (!bitmap_get(objects, bitmap_git->pack->num_objects + i))
+		if (!bitmap_get(objects, bitmap_num_objects(bitmap_git) + i))
 			continue;
 
 		obj = eindex->objects[i];
@@ -737,6 +901,7 @@
 			continue;
 
 		for (offset = 0; offset < BITS_IN_EWORD; ++offset) {
+			struct packed_git *pack;
 			struct object_id oid;
 			uint32_t hash = 0, index_pos;
 			off_t ofs;
@@ -746,14 +911,28 @@
 
 			offset += ewah_bit_ctz64(word >> offset);
 
-			index_pos = pack_pos_to_index(bitmap_git->pack, pos + offset);
-			ofs = pack_pos_to_offset(bitmap_git->pack, pos + offset);
-			nth_packed_object_id(&oid, bitmap_git->pack, index_pos);
+			if (bitmap_is_midx(bitmap_git)) {
+				struct multi_pack_index *m = bitmap_git->midx;
+				uint32_t pack_id;
+
+				index_pos = pack_pos_to_midx(m, pos + offset);
+				ofs = nth_midxed_offset(m, index_pos);
+				nth_midxed_object_oid(&oid, m, index_pos);
+
+				pack_id = nth_midxed_pack_int_id(m, index_pos);
+				pack = bitmap_git->midx->packs[pack_id];
+			} else {
+				index_pos = pack_pos_to_index(bitmap_git->pack, pos + offset);
+				ofs = pack_pos_to_offset(bitmap_git->pack, pos + offset);
+				nth_bitmap_object_oid(bitmap_git, &oid, index_pos);
+
+				pack = bitmap_git->pack;
+			}
 
 			if (bitmap_git->hashes)
 				hash = get_be32(bitmap_git->hashes + index_pos);
 
-			show_reach(&oid, object_type, 0, hash, bitmap_git->pack, ofs);
+			show_reach(&oid, object_type, 0, hash, pack, ofs);
 		}
 	}
 }
@@ -765,8 +944,13 @@
 		struct object *object = roots->item;
 		roots = roots->next;
 
-		if (find_pack_entry_one(object->oid.hash, bitmap_git->pack) > 0)
-			return 1;
+		if (bitmap_is_midx(bitmap_git)) {
+			if (bsearch_midx(&object->oid, bitmap_git->midx, NULL))
+				return 1;
+		} else {
+			if (find_pack_entry_one(object->oid.hash, bitmap_git->pack) > 0)
+				return 1;
+		}
 	}
 
 	return 0;
@@ -832,7 +1016,7 @@
 	 * them individually.
 	 */
 	for (i = 0; i < eindex->count; i++) {
-		uint32_t pos = i + bitmap_git->pack->num_objects;
+		uint32_t pos = i + bitmap_num_objects(bitmap_git);
 		if (eindex->objects[i]->type == type &&
 		    bitmap_get(to_filter, pos) &&
 		    !bitmap_get(tips, pos))
@@ -853,23 +1037,35 @@
 static unsigned long get_size_by_pos(struct bitmap_index *bitmap_git,
 				     uint32_t pos)
 {
-	struct packed_git *pack = bitmap_git->pack;
 	unsigned long size;
 	struct object_info oi = OBJECT_INFO_INIT;
 
 	oi.sizep = &size;
 
-	if (pos < pack->num_objects) {
-		off_t ofs = pack_pos_to_offset(pack, pos);
+	if (pos < bitmap_num_objects(bitmap_git)) {
+		struct packed_git *pack;
+		off_t ofs;
+
+		if (bitmap_is_midx(bitmap_git)) {
+			uint32_t midx_pos = pack_pos_to_midx(bitmap_git->midx, pos);
+			uint32_t pack_id = nth_midxed_pack_int_id(bitmap_git->midx, midx_pos);
+
+			pack = bitmap_git->midx->packs[pack_id];
+			ofs = nth_midxed_offset(bitmap_git->midx, midx_pos);
+		} else {
+			pack = bitmap_git->pack;
+			ofs = pack_pos_to_offset(pack, pos);
+		}
+
 		if (packed_object_info(the_repository, pack, ofs, &oi) < 0) {
 			struct object_id oid;
-			nth_packed_object_id(&oid, pack,
-					     pack_pos_to_index(pack, pos));
+			nth_bitmap_object_oid(bitmap_git, &oid,
+					      pack_pos_to_index(pack, pos));
 			die(_("unable to get size of %s"), oid_to_hex(&oid));
 		}
 	} else {
 		struct eindex *eindex = &bitmap_git->ext_index;
-		struct object *obj = eindex->objects[pos - pack->num_objects];
+		struct object *obj = eindex->objects[pos - bitmap_num_objects(bitmap_git)];
 		if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
 			die(_("unable to get size of %s"), oid_to_hex(&obj->oid));
 	}
@@ -911,7 +1107,7 @@
 	}
 
 	for (i = 0; i < eindex->count; i++) {
-		uint32_t pos = i + bitmap_git->pack->num_objects;
+		uint32_t pos = i + bitmap_num_objects(bitmap_git);
 		if (eindex->objects[i]->type == OBJ_BLOB &&
 		    bitmap_get(to_filter, pos) &&
 		    !bitmap_get(tips, pos) &&
@@ -1041,7 +1237,7 @@
 	/* try to open a bitmapped pack, but don't parse it yet
 	 * because we may not need to use it */
 	CALLOC_ARRAY(bitmap_git, 1);
-	if (open_pack_bitmap(revs->repo, bitmap_git) < 0)
+	if (open_bitmap(revs->repo, bitmap_git) < 0)
 		goto cleanup;
 
 	for (i = 0; i < revs->pending.nr; ++i) {
@@ -1085,7 +1281,7 @@
 	 * from disk. this is the point of no return; after this the rev_list
 	 * becomes invalidated and we must perform the revwalk through bitmaps
 	 */
-	if (load_pack_bitmap(bitmap_git) < 0)
+	if (load_bitmap(bitmap_git) < 0)
 		goto cleanup;
 
 	object_array_clear(&revs->pending);
@@ -1128,22 +1324,49 @@
 	return NULL;
 }
 
-static void try_partial_reuse(struct bitmap_index *bitmap_git,
-			      size_t pos,
-			      struct bitmap *reuse,
-			      struct pack_window **w_curs)
+/*
+ * -1 means "stop trying further objects"; 0 means we may or may not have
+ * reused, but you can keep feeding bits.
+ */
+static int try_partial_reuse(struct packed_git *pack,
+			     size_t pos,
+			     struct bitmap *reuse,
+			     struct pack_window **w_curs)
 {
-	off_t offset, header;
+	off_t offset, delta_obj_offset;
 	enum object_type type;
 	unsigned long size;
 
-	if (pos >= bitmap_git->pack->num_objects)
-		return; /* not actually in the pack */
+	/*
+	 * try_partial_reuse() is called either on (a) objects in the
+	 * bitmapped pack (in the case of a single-pack bitmap) or (b)
+	 * objects in the preferred pack of a multi-pack bitmap.
+	 * Importantly, the latter can pretend as if only a single pack
+	 * exists because:
+	 *
+	 *   - The first pack->num_objects bits of a MIDX bitmap are
+	 *     reserved for the preferred pack, and
+	 *
+	 *   - Ties due to duplicate objects are always resolved in
+	 *     favor of the preferred pack.
+	 *
+	 * Therefore we do not need to ever ask the MIDX for its copy of
+	 * an object by OID, since it will always select it from the
+	 * preferred pack. Likewise, the selected copy of the base
+	 * object for any deltas will reside in the same pack.
+	 *
+	 * This means that we can reuse pos when looking up the bit in
+	 * the reuse bitmap, too, since bits corresponding to the
+	 * preferred pack precede all bits from other packs.
+	 */
 
-	offset = header = pack_pos_to_offset(bitmap_git->pack, pos);
-	type = unpack_object_header(bitmap_git->pack, w_curs, &offset, &size);
+	if (pos >= pack->num_objects)
+		return -1; /* not actually in the pack or MIDX preferred pack */
+
+	offset = delta_obj_offset = pack_pos_to_offset(pack, pos);
+	type = unpack_object_header(pack, w_curs, &offset, &size);
 	if (type < 0)
-		return; /* broken packfile, punt */
+		return -1; /* broken packfile, punt */
 
 	if (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA) {
 		off_t base_offset;
@@ -1157,12 +1380,12 @@
 		 * and the normal slow path will complain about it in
 		 * more detail.
 		 */
-		base_offset = get_delta_base(bitmap_git->pack, w_curs,
-					     &offset, type, header);
+		base_offset = get_delta_base(pack, w_curs, &offset, type,
+					     delta_obj_offset);
 		if (!base_offset)
-			return;
-		if (offset_to_pack_pos(bitmap_git->pack, base_offset, &base_pos) < 0)
-			return;
+			return 0;
+		if (offset_to_pack_pos(pack, base_offset, &base_pos) < 0)
+			return 0;
 
 		/*
 		 * We assume delta dependencies always point backwards. This
@@ -1174,7 +1397,7 @@
 		 * odd parameters.
 		 */
 		if (base_pos >= pos)
-			return;
+			return 0;
 
 		/*
 		 * And finally, if we're not sending the base as part of our
@@ -1185,13 +1408,22 @@
 		 * object_entry code path handle it.
 		 */
 		if (!bitmap_get(reuse, base_pos))
-			return;
+			return 0;
 	}
 
 	/*
 	 * If we got here, then the object is OK to reuse. Mark it.
 	 */
 	bitmap_set(reuse, pos);
+	return 0;
+}
+
+uint32_t midx_preferred_pack(struct bitmap_index *bitmap_git)
+{
+	struct multi_pack_index *m = bitmap_git->midx;
+	if (!m)
+		BUG("midx_preferred_pack: requires non-empty MIDX");
+	return nth_midxed_pack_int_id(m, pack_pos_to_midx(bitmap_git->midx, 0));
 }
 
 int reuse_partial_packfile_from_bitmap(struct bitmap_index *bitmap_git,
@@ -1199,20 +1431,37 @@
 				       uint32_t *entries,
 				       struct bitmap **reuse_out)
 {
+	struct packed_git *pack;
 	struct bitmap *result = bitmap_git->result;
 	struct bitmap *reuse;
 	struct pack_window *w_curs = NULL;
 	size_t i = 0;
 	uint32_t offset;
+	uint32_t objects_nr;
 
 	assert(result);
 
+	load_reverse_index(bitmap_git);
+
+	if (bitmap_is_midx(bitmap_git))
+		pack = bitmap_git->midx->packs[midx_preferred_pack(bitmap_git)];
+	else
+		pack = bitmap_git->pack;
+	objects_nr = pack->num_objects;
+
 	while (i < result->word_alloc && result->words[i] == (eword_t)~0)
 		i++;
 
-	/* Don't mark objects not in the packfile */
-	if (i > bitmap_git->pack->num_objects / BITS_IN_EWORD)
-		i = bitmap_git->pack->num_objects / BITS_IN_EWORD;
+	/*
+	 * Don't mark objects not in the packfile or preferred pack. This bitmap
+	 * marks objects eligible for reuse, but the pack-reuse code only
+	 * understands how to reuse a single pack. Since the preferred pack is
+	 * guaranteed to have all bases for its deltas (in a multi-pack bitmap),
+	 * we use it instead of another pack. In single-pack bitmaps, the choice
+	 * is made for us.
+	 */
+	if (i > objects_nr / BITS_IN_EWORD)
+		i = objects_nr / BITS_IN_EWORD;
 
 	reuse = bitmap_word_alloc(i);
 	memset(reuse->words, 0xFF, i * sizeof(eword_t));
@@ -1226,10 +1475,23 @@
 				break;
 
 			offset += ewah_bit_ctz64(word >> offset);
-			try_partial_reuse(bitmap_git, pos + offset, reuse, &w_curs);
+			if (try_partial_reuse(pack, pos + offset,
+					      reuse, &w_curs) < 0) {
+				/*
+				 * try_partial_reuse indicated we couldn't reuse
+				 * any bits, so there is no point in trying more
+				 * bits in the current word, or any other words
+				 * in result.
+				 *
+				 * Jump out of both loops to avoid future
+				 * unnecessary calls to try_partial_reuse.
+				 */
+				goto done;
+			}
 		}
 	}
 
+done:
 	unuse_pack(&w_curs);
 
 	*entries = bitmap_popcount(reuse);
@@ -1243,7 +1505,7 @@
 	 * need to be handled separately.
 	 */
 	bitmap_and_not(result, reuse);
-	*packfile_out = bitmap_git->pack;
+	*packfile_out = pack;
 	*reuse_out = reuse;
 	return 0;
 }
@@ -1296,7 +1558,7 @@
 
 	for (i = 0; i < eindex->count; ++i) {
 		if (eindex->objects[i]->type == type &&
-			bitmap_get(objects, bitmap_git->pack->num_objects + i))
+			bitmap_get(objects, bitmap_num_objects(bitmap_git) + i))
 			count++;
 	}
 
@@ -1325,10 +1587,52 @@
 struct bitmap_test_data {
 	struct bitmap_index *bitmap_git;
 	struct bitmap *base;
+	struct bitmap *commits;
+	struct bitmap *trees;
+	struct bitmap *blobs;
+	struct bitmap *tags;
 	struct progress *prg;
 	size_t seen;
 };
 
+static void test_bitmap_type(struct bitmap_test_data *tdata,
+			     struct object *obj, int pos)
+{
+	enum object_type bitmap_type = OBJ_NONE;
+	int bitmaps_nr = 0;
+
+	if (bitmap_get(tdata->commits, pos)) {
+		bitmap_type = OBJ_COMMIT;
+		bitmaps_nr++;
+	}
+	if (bitmap_get(tdata->trees, pos)) {
+		bitmap_type = OBJ_TREE;
+		bitmaps_nr++;
+	}
+	if (bitmap_get(tdata->blobs, pos)) {
+		bitmap_type = OBJ_BLOB;
+		bitmaps_nr++;
+	}
+	if (bitmap_get(tdata->tags, pos)) {
+		bitmap_type = OBJ_TAG;
+		bitmaps_nr++;
+	}
+
+	if (bitmap_type == OBJ_NONE)
+		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",
+		    oid_to_hex(&obj->oid));
+
+	if (bitmap_type != obj->type)
+		die("object %s: real type %s, expected: %s",
+		    oid_to_hex(&obj->oid),
+		    type_name(obj->type),
+		    type_name(bitmap_type));
+}
+
 static void test_show_object(struct object *object, const char *name,
 			     void *data)
 {
@@ -1338,6 +1642,7 @@
 	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));
+	test_bitmap_type(tdata, object, bitmap_pos);
 
 	bitmap_set(tdata->base, bitmap_pos);
 	display_progress(tdata->prg, ++tdata->seen);
@@ -1352,6 +1657,7 @@
 				     &commit->object.oid);
 	if (bitmap_pos < 0)
 		die("Object not in bitmap: %s\n", oid_to_hex(&commit->object.oid));
+	test_bitmap_type(tdata, &commit->object, bitmap_pos);
 
 	bitmap_set(tdata->base, bitmap_pos);
 	display_progress(tdata->prg, ++tdata->seen);
@@ -1399,6 +1705,10 @@
 
 	tdata.bitmap_git = bitmap_git;
 	tdata.base = bitmap_new();
+	tdata.commits = ewah_to_bitmap(bitmap_git->commits);
+	tdata.trees = ewah_to_bitmap(bitmap_git->trees);
+	tdata.blobs = ewah_to_bitmap(bitmap_git->blobs);
+	tdata.tags = ewah_to_bitmap(bitmap_git->tags);
 	tdata.prg = start_progress("Verifying bitmap entries", result_popcnt);
 	tdata.seen = 0;
 
@@ -1432,6 +1742,33 @@
 	return 0;
 }
 
+int test_bitmap_hashes(struct repository *r)
+{
+	struct bitmap_index *bitmap_git = prepare_bitmap_git(r);
+	struct object_id oid;
+	uint32_t i, index_pos;
+
+	if (!bitmap_git->hashes)
+		goto cleanup;
+
+	for (i = 0; i < bitmap_num_objects(bitmap_git); i++) {
+		if (bitmap_is_midx(bitmap_git))
+			index_pos = pack_pos_to_midx(bitmap_git->midx, i);
+		else
+			index_pos = pack_pos_to_index(bitmap_git->pack, i);
+
+		nth_bitmap_object_oid(bitmap_git, &oid, index_pos);
+
+		printf("%s %"PRIu32"\n",
+		       oid_to_hex(&oid), get_be32(bitmap_git->hashes + index_pos));
+	}
+
+cleanup:
+	free_bitmap_index(bitmap_git);
+
+	return 0;
+}
+
 int rebuild_bitmap(const uint32_t *reposition,
 		   struct ewah_bitmap *source,
 		   struct bitmap *dest)
@@ -1469,19 +1806,32 @@
 	uint32_t i, num_objects;
 	uint32_t *reposition;
 
-	num_objects = bitmap_git->pack->num_objects;
+	if (!bitmap_is_midx(bitmap_git))
+		load_reverse_index(bitmap_git);
+	else if (load_midx_revindex(bitmap_git->midx) < 0)
+		BUG("rebuild_existing_bitmaps: missing required rev-cache "
+		    "extension");
+
+	num_objects = bitmap_num_objects(bitmap_git);
 	CALLOC_ARRAY(reposition, num_objects);
 
 	for (i = 0; i < num_objects; ++i) {
 		struct object_id oid;
 		struct object_entry *oe;
+		uint32_t index_pos;
 
-		nth_packed_object_id(&oid, bitmap_git->pack,
-				     pack_pos_to_index(bitmap_git->pack, i));
+		if (bitmap_is_midx(bitmap_git))
+			index_pos = pack_pos_to_midx(bitmap_git->midx, i);
+		else
+			index_pos = pack_pos_to_index(bitmap_git->pack, i);
+		nth_bitmap_object_oid(bitmap_git, &oid, index_pos);
 		oe = packlist_find(mapping, &oid);
 
-		if (oe)
+		if (oe) {
 			reposition[i] = oe_in_pack_pos(mapping, oe) + 1;
+			if (bitmap_git->hashes && !oe->hash)
+				oe->hash = get_be32(bitmap_git->hashes + index_pos);
+		}
 	}
 
 	return reposition;
@@ -1503,6 +1853,19 @@
 	free(b->ext_index.hashes);
 	bitmap_free(b->result);
 	bitmap_free(b->haves);
+	if (bitmap_is_midx(b)) {
+		/*
+		 * Multi-pack bitmaps need to have resources associated with
+		 * their on-disk reverse indexes unmapped so that stale .rev and
+		 * .bitmap files can be removed.
+		 *
+		 * Unlike pack-based bitmaps, multi-pack bitmaps can be read and
+		 * written in the same 'git multi-pack-index write --bitmap'
+		 * process. Close resources so they can be removed safely on
+		 * platforms like Windows.
+		 */
+		close_midx_revindex(b->midx);
+	}
 	free(b);
 }
 
@@ -1517,7 +1880,6 @@
 				     enum object_type object_type)
 {
 	struct bitmap *result = bitmap_git->result;
-	struct packed_git *pack = bitmap_git->pack;
 	off_t total = 0;
 	struct ewah_iterator it;
 	eword_t filter;
@@ -1534,15 +1896,35 @@
 			continue;
 
 		for (offset = 0; offset < BITS_IN_EWORD; offset++) {
-			size_t pos;
-
 			if ((word >> offset) == 0)
 				break;
 
 			offset += ewah_bit_ctz64(word >> offset);
-			pos = base + offset;
-			total += pack_pos_to_offset(pack, pos + 1) -
-				 pack_pos_to_offset(pack, pos);
+
+			if (bitmap_is_midx(bitmap_git)) {
+				uint32_t pack_pos;
+				uint32_t midx_pos = pack_pos_to_midx(bitmap_git->midx, base + offset);
+				off_t offset = nth_midxed_offset(bitmap_git->midx, midx_pos);
+
+				uint32_t pack_id = nth_midxed_pack_int_id(bitmap_git->midx, midx_pos);
+				struct packed_git *pack = bitmap_git->midx->packs[pack_id];
+
+				if (offset_to_pack_pos(pack, offset, &pack_pos) < 0) {
+					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),
+					    oid_to_hex(&oid),
+					    pack->pack_name,
+					    (uintmax_t)offset);
+				}
+
+				total += pack_pos_to_offset(pack, pack_pos + 1) - offset;
+			} else {
+				size_t pos = base + offset;
+				total += pack_pos_to_offset(bitmap_git->pack, pos + 1) -
+					 pack_pos_to_offset(bitmap_git->pack, pos);
+			}
 		}
 	}
 
@@ -1552,7 +1934,6 @@
 static off_t get_disk_usage_for_extended(struct bitmap_index *bitmap_git)
 {
 	struct bitmap *result = bitmap_git->result;
-	struct packed_git *pack = bitmap_git->pack;
 	struct eindex *eindex = &bitmap_git->ext_index;
 	off_t total = 0;
 	struct object_info oi = OBJECT_INFO_INIT;
@@ -1564,7 +1945,7 @@
 	for (i = 0; i < eindex->count; i++) {
 		struct object *obj = eindex->objects[i];
 
-		if (!bitmap_get(result, pack->num_objects + i))
+		if (!bitmap_get(result, bitmap_num_objects(bitmap_git) + i))
 			continue;
 
 		if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0)
@@ -1594,7 +1975,28 @@
 	return total;
 }
 
+int bitmap_is_midx(struct bitmap_index *bitmap_git)
+{
+	return !!bitmap_git->midx;
+}
+
 const struct string_list *bitmap_preferred_tips(struct repository *r)
 {
 	return repo_config_get_value_multi(r, "pack.preferbitmaptips");
 }
+
+int bitmap_is_preferred_refname(struct repository *r, const char *refname)
+{
+	const struct string_list *preferred_tips = bitmap_preferred_tips(r);
+	struct string_list_item *item;
+
+	if (!preferred_tips)
+		return 0;
+
+	for_each_string_list_item(item, preferred_tips) {
+		if (starts_with(refname, item->string))
+			return 1;
+	}
+
+	return 0;
+}
diff --git a/pack-bitmap.h b/pack-bitmap.h
index 99d733e..19a63fa 100644
--- a/pack-bitmap.h
+++ b/pack-bitmap.h
@@ -44,6 +44,7 @@
 struct bitmap_index;
 
 struct bitmap_index *prepare_bitmap_git(struct repository *r);
+struct bitmap_index *prepare_midx_bitmap_git(struct multi_pack_index *midx);
 void count_bitmap_commit_list(struct bitmap_index *, uint32_t *commits,
 			      uint32_t *trees, uint32_t *blobs, uint32_t *tags);
 void traverse_bitmap_commit_list(struct bitmap_index *,
@@ -51,9 +52,11 @@
 				 show_reachable_fn show_reachable);
 void test_bitmap_walk(struct rev_info *revs);
 int test_bitmap_commits(struct repository *r);
+int test_bitmap_hashes(struct repository *r);
 struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs,
 					 struct list_objects_filter_options *filter,
 					 int filter_provided_objects);
+uint32_t midx_preferred_pack(struct bitmap_index *bitmap_git);
 int reuse_partial_packfile_from_bitmap(struct bitmap_index *,
 				       struct packed_git **packfile,
 				       uint32_t *entries,
@@ -87,12 +90,17 @@
 				      struct commit *commit);
 void bitmap_writer_select_commits(struct commit **indexed_commits,
 		unsigned int indexed_commits_nr, int max_bitmaps);
-void bitmap_writer_build(struct packing_data *to_pack);
+int bitmap_writer_build(struct packing_data *to_pack);
 void bitmap_writer_finish(struct pack_idx_entry **index,
 			  uint32_t index_nr,
 			  const char *filename,
 			  uint16_t options);
+char *midx_bitmap_filename(struct multi_pack_index *midx);
+char *pack_bitmap_filename(struct packed_git *p);
+
+int bitmap_is_midx(struct bitmap_index *bitmap_git);
 
 const struct string_list *bitmap_preferred_tips(struct repository *r);
+int bitmap_is_preferred_refname(struct repository *r, const char *refname);
 
 #endif
diff --git a/pack-check.c b/pack-check.c
index c8e560d..3f418e3 100644
--- a/pack-check.c
+++ b/pack-check.c
@@ -142,7 +142,8 @@
 			err = error("cannot unpack %s from %s at offset %"PRIuMAX"",
 				    oid_to_hex(&oid), p->pack_name,
 				    (uintmax_t)entries[i].offset);
-		else if (check_object_signature(r, &oid, data, size, type_name(type)))
+		else if (check_object_signature(r, &oid, data, size,
+						type_name(type), NULL))
 			err = error("packed %s from %s is corrupt",
 				    oid_to_hex(&oid), p->pack_name);
 		else if (fn) {
diff --git a/packfile.c b/packfile.c
index 9ef6d98..89402cf 100644
--- a/packfile.c
+++ b/packfile.c
@@ -339,6 +339,7 @@
 	close_pack_fd(p);
 	close_pack_index(p);
 	close_pack_revindex(p);
+	oidset_clear(&p->bad_objects);
 }
 
 void close_object_store(struct raw_object_store *o)
@@ -860,7 +861,7 @@
 	if (!strcmp(file_name, "multi-pack-index"))
 		return;
 	if (starts_with(file_name, "multi-pack-index") &&
-	    ends_with(file_name, ".rev"))
+	    (ends_with(file_name, ".bitmap") || ends_with(file_name, ".rev")))
 		return;
 	if (ends_with(file_name, ".idx") ||
 	    ends_with(file_name, ".rev") ||
@@ -1161,31 +1162,19 @@
 	return type;
 }
 
-void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1)
+void mark_bad_packed_object(struct packed_git *p, const struct object_id *oid)
 {
-	unsigned i;
-	const unsigned hashsz = the_hash_algo->rawsz;
-	for (i = 0; i < p->num_bad_objects; i++)
-		if (hasheq(sha1, p->bad_object_sha1 + hashsz * i))
-			return;
-	p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
-				      st_mult(GIT_MAX_RAWSZ,
-					      st_add(p->num_bad_objects, 1)));
-	hashcpy(p->bad_object_sha1 + hashsz * p->num_bad_objects, sha1);
-	p->num_bad_objects++;
+	oidset_insert(&p->bad_objects, oid);
 }
 
 const struct packed_git *has_packed_and_bad(struct repository *r,
-					    const unsigned char *sha1)
+					    const struct object_id *oid)
 {
 	struct packed_git *p;
-	unsigned i;
 
 	for (p = r->objects->packed_git; p; p = p->next)
-		for (i = 0; i < p->num_bad_objects; i++)
-			if (hasheq(sha1,
-				   p->bad_object_sha1 + the_hash_algo->rawsz * i))
-				return p;
+		if (oidset_contains(&p->bad_objects, oid))
+			return p;
 	return NULL;
 }
 
@@ -1272,7 +1261,7 @@
 	if (offset_to_pack_pos(p, obj_offset, &pos) < 0)
 		return OBJ_BAD;
 	nth_packed_object_id(&oid, p, pack_pos_to_index(p, pos));
-	mark_bad_packed_object(p, oid.hash);
+	mark_bad_packed_object(p, &oid);
 	type = oid_object_info(r, &oid, NULL);
 	if (type <= OBJ_NONE)
 		return OBJ_BAD;
@@ -1722,7 +1711,7 @@
 				nth_packed_object_id(&oid, p, index_pos);
 				error("bad packed object CRC for %s",
 				      oid_to_hex(&oid));
-				mark_bad_packed_object(p, oid.hash);
+				mark_bad_packed_object(p, &oid);
 				data = NULL;
 				goto out;
 			}
@@ -1811,7 +1800,7 @@
 				      " at offset %"PRIuMAX" from %s",
 				      oid_to_hex(&base_oid), (uintmax_t)obj_offset,
 				      p->pack_name);
-				mark_bad_packed_object(p, base_oid.hash);
+				mark_bad_packed_object(p, &base_oid);
 				base = read_object(r, &base_oid, &type, &base_size);
 				external_base = base;
 			}
@@ -2016,13 +2005,9 @@
 {
 	off_t offset;
 
-	if (p->num_bad_objects) {
-		unsigned i;
-		for (i = 0; i < p->num_bad_objects; i++)
-			if (hasheq(oid->hash,
-				   p->bad_object_sha1 + the_hash_algo->rawsz * i))
-				return 0;
-	}
+	if (oidset_size(&p->bad_objects) &&
+	    oidset_contains(&p->bad_objects, oid))
+		return 0;
 
 	offset = find_pack_entry_one(oid->hash, p);
 	if (!offset)
@@ -2205,6 +2190,12 @@
 		if ((flags & FOR_EACH_OBJECT_PROMISOR_ONLY) &&
 		    !p->pack_promisor)
 			continue;
+		if ((flags & FOR_EACH_OBJECT_SKIP_IN_CORE_KEPT_PACKS) &&
+		    p->pack_keep_in_core)
+			continue;
+		if ((flags & FOR_EACH_OBJECT_SKIP_ON_DISK_KEPT_PACKS) &&
+		    p->pack_keep)
+			continue;
 		if (open_pack_index(p)) {
 			pack_errors = 1;
 			continue;
diff --git a/packfile.h b/packfile.h
index 3ae117a..1861467 100644
--- a/packfile.h
+++ b/packfile.h
@@ -159,8 +159,8 @@
 		       struct packed_git *pack,
 		       off_t offset, struct object_info *);
 
-void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1);
-const struct packed_git *has_packed_and_bad(struct repository *r, const unsigned char *sha1);
+void mark_bad_packed_object(struct packed_git *, const struct object_id *);
+const struct packed_git *has_packed_and_bad(struct repository *, const struct object_id *);
 
 #define ON_DISK_KEEP_PACKS 1
 #define IN_CORE_KEEP_PACKS 2
diff --git a/parallel-checkout.c b/parallel-checkout.c
index ddc0ff3..ed9c999 100644
--- a/parallel-checkout.c
+++ b/parallel-checkout.c
@@ -603,8 +603,7 @@
 				continue;
 
 			if (pfd->revents & POLLIN) {
-				int len = packet_read(pfd->fd, NULL, NULL,
-						      packet_buffer,
+				int len = packet_read(pfd->fd, packet_buffer,
 						      sizeof(packet_buffer), 0);
 
 				if (len < 0) {
diff --git a/parse-options.c b/parse-options.c
index 2abff13..9a0484c 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -8,10 +8,13 @@
 
 static int disallow_abbreviated_options;
 
-#define OPT_SHORT 1
-#define OPT_UNSET 2
+enum opt_parsed {
+	OPT_LONG  = 0,
+	OPT_SHORT = 1<<0,
+	OPT_UNSET = 1<<1,
+};
 
-int optbug(const struct option *opt, const char *reason)
+static int optbug(const struct option *opt, const char *reason)
 {
 	if (opt->long_name) {
 		if (opt->short_name)
@@ -22,9 +25,26 @@
 	return error("BUG: switch '%c' %s", opt->short_name, reason);
 }
 
+static const char *optname(const struct option *opt, enum opt_parsed flags)
+{
+	static struct strbuf sb = STRBUF_INIT;
+
+	strbuf_reset(&sb);
+	if (flags & OPT_SHORT)
+		strbuf_addf(&sb, "switch `%c'", opt->short_name);
+	else if (flags & OPT_UNSET)
+		strbuf_addf(&sb, "option `no-%s'", opt->long_name);
+	else if (flags == OPT_LONG)
+		strbuf_addf(&sb, "option `%s'", opt->long_name);
+	else
+		BUG("optname() got unknown flags %d", flags);
+
+	return sb.buf;
+}
+
 static enum parse_opt_result get_arg(struct parse_opt_ctx_t *p,
 				     const struct option *opt,
-				     int flags, const char **arg)
+				     enum opt_parsed flags, const char **arg)
 {
 	if (p->opt) {
 		*arg = p->opt;
@@ -50,7 +70,7 @@
 static enum parse_opt_result opt_command_mode_error(
 	const struct option *opt,
 	const struct option *all_opts,
-	int flags)
+	enum opt_parsed flags)
 {
 	const struct option *that;
 	struct strbuf that_name = STRBUF_INIT;
@@ -82,7 +102,7 @@
 static enum parse_opt_result get_value(struct parse_opt_ctx_t *p,
 				       const struct option *opt,
 				       const struct option *all_opts,
-				       int flags)
+				       enum opt_parsed flags)
 {
 	const char *s, *arg;
 	const int unset = flags & OPT_UNSET;
@@ -298,11 +318,11 @@
 	const struct option *all_opts = options;
 	const char *arg_end = strchrnul(arg, '=');
 	const struct option *abbrev_option = NULL, *ambiguous_option = NULL;
-	int abbrev_flags = 0, ambiguous_flags = 0;
+	enum opt_parsed abbrev_flags = OPT_LONG, ambiguous_flags = OPT_LONG;
 
 	for (; options->type != OPTION_END; options++) {
 		const char *rest, *long_name = options->long_name;
-		int flags = 0, opt_flags = 0;
+		enum opt_parsed flags = OPT_LONG, opt_flags = OPT_LONG;
 
 		if (!long_name)
 			continue;
@@ -310,19 +330,6 @@
 again:
 		if (!skip_prefix(arg, long_name, &rest))
 			rest = NULL;
-		if (options->type == OPTION_ARGUMENT) {
-			if (!rest)
-				continue;
-			if (*rest == '=')
-				return error(_("%s takes no value"),
-					     optname(options, flags));
-			if (*rest)
-				continue;
-			if (options->value)
-				*(int *)options->value = options->defval;
-			p->out[p->cpidx++] = arg - 2;
-			return PARSE_OPT_DONE;
-		}
 		if (!rest) {
 			/* abbreviated? */
 			if (!(p->flags & PARSE_OPT_KEEP_UNKNOWN) &&
@@ -494,7 +501,8 @@
 
 static void parse_options_start_1(struct parse_opt_ctx_t *ctx,
 				  int argc, const char **argv, const char *prefix,
-				  const struct option *options, int flags)
+				  const struct option *options,
+				  enum parse_opt_flags flags)
 {
 	ctx->argc = argc;
 	ctx->argv = argv;
@@ -519,7 +527,8 @@
 
 void parse_options_start(struct parse_opt_ctx_t *ctx,
 			 int argc, const char **argv, const char *prefix,
-			 const struct option *options, int flags)
+			 const struct option *options,
+			 enum parse_opt_flags flags)
 {
 	memset(ctx, 0, sizeof(*ctx));
 	parse_options_start_1(ctx, argc, argv, prefix, options, flags);
@@ -710,13 +719,14 @@
 	free(options);
 }
 
-static int usage_with_options_internal(struct parse_opt_ctx_t *,
-				       const char * const *,
-				       const struct option *, int, int);
+static enum parse_opt_result usage_with_options_internal(struct parse_opt_ctx_t *,
+							 const char * const *,
+							 const struct option *,
+							 int, int);
 
-int parse_options_step(struct parse_opt_ctx_t *ctx,
-		       const struct option *options,
-		       const char * const usagestr[])
+enum parse_opt_result parse_options_step(struct parse_opt_ctx_t *ctx,
+					 const struct option *options,
+					 const char * const usagestr[])
 {
 	int internal_help = !(ctx->flags & PARSE_OPT_NO_INTERNAL_HELP);
 
@@ -850,9 +860,11 @@
 	return ctx->cpidx + ctx->argc;
 }
 
-int parse_options(int argc, const char **argv, const char *prefix,
-		  const struct option *options, const char * const usagestr[],
-		  int flags)
+enum parse_opt_result parse_options(int argc, const char **argv,
+				    const char *prefix,
+				    const struct option *options,
+				    const char * const usagestr[],
+				    enum parse_opt_flags flags)
 {
 	struct parse_opt_ctx_t ctx;
 	struct option *real_options;
@@ -874,7 +886,7 @@
 	case PARSE_OPT_NON_OPTION:
 	case PARSE_OPT_DONE:
 		break;
-	default: /* PARSE_OPT_UNKNOWN */
+	case PARSE_OPT_UNKNOWN:
 		if (ctx.argv[0][1] == '-') {
 			error(_("unknown option `%s'"), ctx.argv[0] + 2);
 		} else if (isascii(*ctx.opt)) {
@@ -910,32 +922,85 @@
 #define USAGE_OPTS_WIDTH 24
 #define USAGE_GAP         2
 
-static int usage_with_options_internal(struct parse_opt_ctx_t *ctx,
-				       const char * const *usagestr,
-				       const struct option *opts, int full, int err)
+static enum parse_opt_result usage_with_options_internal(struct parse_opt_ctx_t *ctx,
+							 const char * const *usagestr,
+							 const struct option *opts,
+							 int full, int err)
 {
 	FILE *outfile = err ? stderr : stdout;
 	int need_newline;
 
+	const char *usage_prefix = _("usage: %s");
+	/*
+	 * The translation could be anything, but we can count on
+	 * msgfmt(1)'s --check option to have asserted that "%s" is in
+	 * the translation. So compute the length of the "usage: "
+	 * part. We are assuming that the translator wasn't overly
+	 * clever and used e.g. "%1$s" instead of "%s", there's only
+	 * one "%s" in "usage_prefix" above, so there's no reason to
+	 * do so even with a RTL language.
+	 */
+	size_t usage_len = strlen(usage_prefix) - strlen("%s");
+	/*
+	 * TRANSLATORS: the colon here should align with the
+	 * one in "usage: %s" translation.
+	 */
+	const char *or_prefix = _("   or: %s");
+	/*
+	 * TRANSLATORS: You should only need to translate this format
+	 * string if your language is a RTL language (e.g. Arabic,
+	 * Hebrew etc.), not if it's a LTR language (e.g. German,
+	 * Russian, Chinese etc.).
+	 *
+	 * When a translated usage string has an embedded "\n" it's
+	 * because options have wrapped to the next line. The line
+	 * after the "\n" will then be padded to align with the
+	 * command name, such as N_("git cmd [opt]\n<8
+	 * spaces>[opt2]"), where the 8 spaces are the same length as
+	 * "git cmd ".
+	 *
+	 * This format string prints out that already-translated
+	 * line. The "%*s" is whitespace padding to account for the
+	 * padding at the start of the line that we add in this
+	 * function. The "%s" is a line in the (hopefully already
+	 * translated) N_() usage string, which contained embedded
+	 * newlines before we split it up.
+	 */
+	const char *usage_continued = _("%*s%s");
+	const char *prefix = usage_prefix;
+	int saw_empty_line = 0;
+
 	if (!usagestr)
 		return PARSE_OPT_HELP;
 
 	if (!err && ctx && ctx->flags & PARSE_OPT_SHELL_EVAL)
 		fprintf(outfile, "cat <<\\EOF\n");
 
-	fprintf_ln(outfile, _("usage: %s"), _(*usagestr++));
-	while (*usagestr && **usagestr)
-		/*
-		 * TRANSLATORS: the colon here should align with the
-		 * one in "usage: %s" translation.
-		 */
-		fprintf_ln(outfile, _("   or: %s"), _(*usagestr++));
 	while (*usagestr) {
-		if (**usagestr)
-			fprintf_ln(outfile, _("    %s"), _(*usagestr));
-		else
-			fputc('\n', outfile);
-		usagestr++;
+		const char *str = _(*usagestr++);
+		struct string_list list = STRING_LIST_INIT_DUP;
+		unsigned int j;
+
+		if (!saw_empty_line && !*str)
+			saw_empty_line = 1;
+
+		string_list_split(&list, str, '\n', -1);
+		for (j = 0; j < list.nr; j++) {
+			const char *line = list.items[j].string;
+
+			if (saw_empty_line && *line)
+				fprintf_ln(outfile, _("    %s"), line);
+			else if (saw_empty_line)
+				fputc('\n', outfile);
+			else if (!j)
+				fprintf_ln(outfile, prefix, line);
+			else
+				fprintf_ln(outfile, usage_continued,
+					   (int)usage_len, "", line);
+		}
+		string_list_clear(&list, 0);
+
+		prefix = or_prefix;
 	}
 
 	need_newline = 1;
@@ -1013,18 +1078,3 @@
 	fprintf(stderr, "fatal: %s\n\n", msg);
 	usage_with_options(usagestr, options);
 }
-
-const char *optname(const struct option *opt, int flags)
-{
-	static struct strbuf sb = STRBUF_INIT;
-
-	strbuf_reset(&sb);
-	if (flags & OPT_SHORT)
-		strbuf_addf(&sb, "switch `%c'", opt->short_name);
-	else if (flags & OPT_UNSET)
-		strbuf_addf(&sb, "option `no-%s'", opt->long_name);
-	else
-		strbuf_addf(&sb, "option `%s'", opt->long_name);
-
-	return sb.buf;
-}
diff --git a/parse-options.h b/parse-options.h
index a845a9d..bdea052 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -8,7 +8,6 @@
 enum parse_opt_type {
 	/* special types */
 	OPTION_END,
-	OPTION_ARGUMENT,
 	OPTION_GROUP,
 	OPTION_NUMBER,
 	OPTION_ALIAS,
@@ -34,6 +33,7 @@
 	PARSE_OPT_KEEP_UNKNOWN = 1 << 3,
 	PARSE_OPT_NO_INTERNAL_HELP = 1 << 4,
 	PARSE_OPT_ONE_SHOT = 1 << 5,
+	PARSE_OPT_SHELL_EVAL = 1 << 6,
 };
 
 enum parse_opt_option_flags {
@@ -45,7 +45,6 @@
 	PARSE_OPT_NODASH = 1 << 5,
 	PARSE_OPT_LITERAL_ARGHELP = 1 << 6,
 	PARSE_OPT_FROM_ALIAS = 1 << 7,
-	PARSE_OPT_SHELL_EVAL = 1 << 8,
 	PARSE_OPT_NOCOMPLETE = 1 << 9,
 	PARSE_OPT_COMP_ARG = 1 << 10,
 	PARSE_OPT_CMDMODE = 1 << 11,
@@ -135,7 +134,7 @@
 	const char *argh;
 	const char *help;
 
-	int flags;
+	enum parse_opt_option_flags flags;
 	parse_opt_cb *callback;
 	intptr_t defval;
 	parse_opt_ll_cb *ll_callback;
@@ -155,8 +154,6 @@
 #define OPT_INTEGER_F(s, l, v, h, f)     { OPTION_INTEGER, (s), (l), (v), N_("n"), (h), (f) }
 
 #define OPT_END()                   { OPTION_END }
-#define OPT_ARGUMENT(l, v, h)       { OPTION_ARGUMENT, 0, (l), (v), NULL, \
-				      (h), PARSE_OPT_NOARG, NULL, 1 }
 #define OPT_GROUP(h)                { OPTION_GROUP, 0, NULL, NULL, NULL, (h) }
 #define OPT_BIT(s, l, v, h, b)      OPT_BIT_F(s, l, v, h, b, 0)
 #define OPT_BITOP(s, l, v, h, set, clear) { OPTION_BITOP, (s), (l), (v), NULL, (h), \
@@ -169,8 +166,10 @@
 #define OPT_BOOL(s, l, v, h)        OPT_BOOL_F(s, l, v, h, 0)
 #define OPT_HIDDEN_BOOL(s, l, v, h) { OPTION_SET_INT, (s), (l), (v), NULL, \
 				      (h), PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 1}
-#define OPT_CMDMODE(s, l, v, h, i)  { OPTION_SET_INT, (s), (l), (v), NULL, \
-				      (h), PARSE_OPT_CMDMODE|PARSE_OPT_NOARG|PARSE_OPT_NONEG, NULL, (i) }
+#define OPT_CMDMODE_F(s, l, v, h, i, f)  { OPTION_SET_INT, (s), (l), (v), NULL, \
+				      (h), PARSE_OPT_CMDMODE|PARSE_OPT_NOARG|PARSE_OPT_NONEG | (f), NULL, (i) }
+#define OPT_CMDMODE(s, l, v, h, i)  OPT_CMDMODE_F(s, l, v, h, i, 0)
+
 #define OPT_INTEGER(s, l, v, h)     OPT_INTEGER_F(s, l, v, h, 0)
 #define OPT_MAGNITUDE(s, l, v, h)   { OPTION_MAGNITUDE, (s), (l), (v), \
 				      N_("n"), (h), PARSE_OPT_NONEG }
@@ -214,9 +213,11 @@
  * untouched and parse_options() returns the number of options
  * processed.
  */
-int parse_options(int argc, const char **argv, const char *prefix,
-		  const struct option *options,
-		  const char * const usagestr[], int flags);
+enum parse_opt_result parse_options(int argc, const char **argv,
+				    const char *prefix,
+				    const struct option *options,
+				    const char * const usagestr[],
+				    enum parse_opt_flags flags);
 
 NORETURN void usage_with_options(const char * const *usagestr,
 				 const struct option *options);
@@ -225,9 +226,6 @@
 			    const char * const *usagestr,
 			    const struct option *options);
 
-int optbug(const struct option *opt, const char *reason);
-const char *optname(const struct option *opt, int flags);
-
 /*
  * Use these assertions for callbacks that expect to be called with NONEG and
  * NOARG respectively, and do not otherwise handle the "unset" and "arg"
@@ -265,7 +263,7 @@
 	const char **out;
 	int argc, cpidx, total;
 	const char *opt;
-	int flags;
+	enum parse_opt_flags flags;
 	const char *prefix;
 	const char **alias_groups; /* must be in groups of 3 elements! */
 	struct option *updated_options;
@@ -273,11 +271,12 @@
 
 void parse_options_start(struct parse_opt_ctx_t *ctx,
 			 int argc, const char **argv, const char *prefix,
-			 const struct option *options, int flags);
+			 const struct option *options,
+			 enum parse_opt_flags flags);
 
-int parse_options_step(struct parse_opt_ctx_t *ctx,
-		       const struct option *options,
-		       const char * const usagestr[]);
+enum parse_opt_result parse_options_step(struct parse_opt_ctx_t *ctx,
+					 const struct option *options,
+					 const char * const usagestr[]);
 
 int parse_options_end(struct parse_opt_ctx_t *ctx);
 
diff --git a/path.c b/path.c
index 7bccd83..2c89547 100644
--- a/path.c
+++ b/path.c
@@ -12,6 +12,7 @@
 #include "packfile.h"
 #include "object-store.h"
 #include "lockfile.h"
+#include "exec-cmd.h"
 
 static int get_st_mode_bits(const char *path, int *mode)
 {
@@ -719,19 +720,25 @@
 }
 
 /*
- * Return a string with ~ and ~user expanded via getpw*.  If buf != NULL,
- * then it is a newly allocated string. Returns NULL on getpw failure or
- * if path is NULL.
+ * Return a string with ~ and ~user expanded via getpw*. Returns NULL on getpw
+ * failure or if path is NULL.
  *
- * If real_home is true, strbuf_realpath($HOME) is used in the expansion.
+ * If real_home is true, strbuf_realpath($HOME) is used in the `~/` expansion.
+ *
+ * If the path starts with `%(prefix)/`, the remainder is interpreted as
+ * relative to where Git is installed, and expanded to the absolute path.
  */
-char *expand_user_path(const char *path, int real_home)
+char *interpolate_path(const char *path, int real_home)
 {
 	struct strbuf user_path = STRBUF_INIT;
 	const char *to_copy = path;
 
 	if (path == NULL)
 		goto return_null;
+
+	if (skip_prefix(path, "%(prefix)/", &path))
+		return system_path(path);
+
 	if (path[0] == '~') {
 		const char *first_slash = strchrnul(path, '/');
 		const char *username = path + 1;
@@ -812,7 +819,7 @@
 		strbuf_add(&validated_path, path, len);
 
 		if (used_path.buf[0] == '~') {
-			char *newpath = expand_user_path(used_path.buf, 0);
+			char *newpath = interpolate_path(used_path.buf, 0);
 			if (!newpath)
 				return NULL;
 			strbuf_attach(&used_path, newpath, strlen(newpath),
@@ -1503,21 +1510,28 @@
 	return str && str[0] == '-';
 }
 
-char *xdg_config_home(const char *filename)
+char *xdg_config_home_for(const char *subdir, const char *filename)
 {
 	const char *home, *config_home;
 
+	assert(subdir);
 	assert(filename);
 	config_home = getenv("XDG_CONFIG_HOME");
 	if (config_home && *config_home)
-		return mkpathdup("%s/git/%s", config_home, filename);
+		return mkpathdup("%s/%s/%s", config_home, subdir, filename);
 
 	home = getenv("HOME");
 	if (home)
-		return mkpathdup("%s/.config/git/%s", home, filename);
+		return mkpathdup("%s/.config/%s/%s", home, subdir, filename);
+
 	return NULL;
 }
 
+char *xdg_config_home(const char *filename)
+{
+	return xdg_config_home_for("git", filename);
+}
+
 char *xdg_cache_home(const char *filename)
 {
 	const char *home, *cache_home;
diff --git a/path.h b/path.h
index 251c78d..b68691a 100644
--- a/path.h
+++ b/path.h
@@ -181,10 +181,7 @@
 	const char *shallow;
 };
 
-#define PATH_CACHE_INIT                                        \
-	{                                                      \
-		NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL \
-	}
+#define PATH_CACHE_INIT { 0 }
 
 const char *git_path_squash_msg(struct repository *r);
 const char *git_path_merge_msg(struct repository *r);
diff --git a/pathspec.c b/pathspec.c
index 08f8d3e..ddeeba7 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -37,11 +37,10 @@
 			num_unmatched++;
 	if (!num_unmatched)
 		return;
-	/* TODO: audit for interaction with sparse-index. */
-	ensure_full_index(istate);
 	for (i = 0; i < istate->cache_nr; i++) {
 		const struct cache_entry *ce = istate->cache[i];
-		if (sw_action == PS_IGNORE_SKIP_WORKTREE && ce_skip_worktree(ce))
+		if (sw_action == PS_IGNORE_SKIP_WORKTREE &&
+		    (ce_skip_worktree(ce) || !path_in_sparse_checkout(ce->name, istate)))
 			continue;
 		ce_path_match(istate, ce, pathspec, seen);
 	}
@@ -72,7 +71,7 @@
 
 	for (i = 0; i < istate->cache_nr; i++) {
 		struct cache_entry *ce = istate->cache[i];
-		if (ce_skip_worktree(ce))
+		if (ce_skip_worktree(ce) || !path_in_sparse_checkout(ce->name, istate))
 		    ce_path_match(istate, ce, pathspec, seen);
 	}
 
diff --git a/pkt-line.c b/pkt-line.c
index 9f63eae..2dc8ac2 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -243,6 +243,43 @@
 		die("%s", err.buf);
 }
 
+void packet_fwrite(FILE *f, const char *buf, size_t size)
+{
+	size_t packet_size;
+	char header[4];
+
+	if (size > LARGE_PACKET_DATA_MAX)
+		die(_("packet write failed - data exceeds max packet size"));
+
+	packet_trace(buf, size, 1);
+	packet_size = size + 4;
+
+	set_packet_header(header, packet_size);
+	fwrite_or_die(f, header, 4);
+	fwrite_or_die(f, buf, size);
+}
+
+void packet_fwrite_fmt(FILE *fh, const char *fmt, ...)
+{
+       static struct strbuf buf = STRBUF_INIT;
+       va_list args;
+
+       strbuf_reset(&buf);
+
+       va_start(args, fmt);
+       format_packet(&buf, "", fmt, args);
+       va_end(args);
+
+       fwrite_or_die(fh, buf.buf, buf.len);
+}
+
+void packet_fflush(FILE *f)
+{
+	packet_trace("0000", 4, 1);
+	fwrite_or_die(f, "0000", 4);
+	fflush_or_die(f);
+}
+
 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
 {
 	va_list args;
@@ -252,22 +289,6 @@
 	va_end(args);
 }
 
-void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len)
-{
-	size_t orig_len, n;
-
-	orig_len = buf->len;
-	strbuf_addstr(buf, "0000");
-	strbuf_add(buf, data, len);
-	n = buf->len - orig_len;
-
-	if (n > LARGE_PACKET_MAX)
-		die(_("protocol error: impossibly long line"));
-
-	set_packet_header(&buf->buf[orig_len], n);
-	packet_trace(data, len, 1);
-}
-
 int write_packetized_from_fd_no_flush(int fd_in, int fd_out)
 {
 	char *buf = xmalloc(LARGE_PACKET_DATA_MAX);
@@ -416,38 +437,28 @@
 	return PACKET_READ_NORMAL;
 }
 
-int packet_read(int fd, char **src_buffer, size_t *src_len,
-		char *buffer, unsigned size, int options)
+int packet_read(int fd, char *buffer, unsigned size, int options)
 {
 	int pktlen = -1;
 
-	packet_read_with_status(fd, src_buffer, src_len, buffer, size,
-				&pktlen, options);
+	packet_read_with_status(fd, NULL, NULL, buffer, size, &pktlen,
+				options);
 
 	return pktlen;
 }
 
-static char *packet_read_line_generic(int fd,
-				      char **src, size_t *src_len,
-				      int *dst_len)
+char *packet_read_line(int fd, int *dst_len)
 {
-	int len = packet_read(fd, src, src_len,
-			      packet_buffer, sizeof(packet_buffer),
+	int len = packet_read(fd, packet_buffer, sizeof(packet_buffer),
 			      PACKET_READ_CHOMP_NEWLINE);
 	if (dst_len)
 		*dst_len = len;
 	return (len > 0) ? packet_buffer : NULL;
 }
 
-char *packet_read_line(int fd, int *len_p)
-{
-	return packet_read_line_generic(fd, NULL, NULL, len_p);
-}
-
 int packet_read_line_gently(int fd, int *dst_len, char **dst_line)
 {
-	int len = packet_read(fd, NULL, NULL,
-			      packet_buffer, sizeof(packet_buffer),
+	int len = packet_read(fd, packet_buffer, sizeof(packet_buffer),
 			      PACKET_READ_CHOMP_NEWLINE|PACKET_READ_GENTLE_ON_EOF);
 	if (dst_len)
 		*dst_len = len;
@@ -456,11 +467,6 @@
 	return len;
 }
 
-char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
-{
-	return packet_read_line_generic(-1, src, src_len, dst_len);
-}
-
 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out, int options)
 {
 	int packet_len;
@@ -470,7 +476,7 @@
 
 	for (;;) {
 		strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
-		packet_len = packet_read(fd_in, NULL, NULL,
+		packet_len = packet_read(fd_in,
 			/* strbuf_grow() above always allocates one extra byte to
 			 * store a '\0' at the end of the string. packet_read()
 			 * writes a '\0' extra byte at the end, too. Let it know
diff --git a/pkt-line.h b/pkt-line.h
index 5af5f45..467ae01 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -29,13 +29,23 @@
 void set_packet_header(char *buf, int size);
 void packet_write(int fd_out, const char *buf, size_t size);
 void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
-void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len);
 int packet_flush_gently(int fd);
 int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
 int write_packetized_from_fd_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);
 
 /*
+ * Stdio versions of packet_write functions. When mixing these with fd
+ * based functions, take care to call fflush(3) before doing fd writes or
+ * closing the fd.
+ */
+void packet_fwrite(FILE *f, const char *buf, size_t size);
+void packet_fwrite_fmt(FILE *f, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
+
+/* packet_fflush writes a flush packet and flushes the stdio buffer of f */
+void packet_fflush(FILE *f);
+
+/*
  * Read a packetized line into the buffer, which must be at least size bytes
  * long. The return value specifies the number of bytes read into the buffer.
  *
@@ -77,8 +87,7 @@
 #define PACKET_READ_CHOMP_NEWLINE        (1u<<1)
 #define PACKET_READ_DIE_ON_ERR_PACKET    (1u<<2)
 #define PACKET_READ_GENTLE_ON_READ_ERROR (1u<<3)
-int packet_read(int fd, char **src_buffer, size_t *src_len, char
-		*buffer, unsigned size, int options);
+int packet_read(int fd, char *buffer, unsigned size, int options);
 
 /*
  * Convert a four hex digit packet line length header into its numeric
@@ -128,12 +137,6 @@
 int packet_read_line_gently(int fd, int *size, char **dst_line);
 
 /*
- * Same as packet_read_line, but read from a buf rather than a descriptor;
- * see packet_read for details on how src_* is used.
- */
-char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size);
-
-/*
  * Reads a stream of variable sized packets until a flush packet is detected.
  */
 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out, int options);
diff --git a/pretty.c b/pretty.c
index 73b5ead..be477bd 100644
--- a/pretty.c
+++ b/pretty.c
@@ -671,11 +671,7 @@
 	 * If the re-encoding failed, out might be NULL here; in that
 	 * case we just return the commit message verbatim.
 	 */
-	if (!out) {
-		warning("unable to reencode commit to '%s'", output_encoding);
-		return msg;
-	}
-	return out;
+	return out ? out : msg;
 }
 
 static int mailmap_name(const char **email, size_t *email_len,
@@ -1436,8 +1432,8 @@
 			check_commit_signature(c->commit, &(c->signature_check));
 		switch (placeholder[1]) {
 		case 'G':
-			if (c->signature_check.gpg_output)
-				strbuf_addstr(sb, c->signature_check.gpg_output);
+			if (c->signature_check.output)
+				strbuf_addstr(sb, c->signature_check.output);
 			break;
 		case '?':
 			switch (c->signature_check.result) {
diff --git a/protocol-caps.c b/protocol-caps.c
index 901b679..bbde918 100644
--- a/protocol-caps.c
+++ b/protocol-caps.c
@@ -75,8 +75,7 @@
 	strbuf_release(&send_buffer);
 }
 
-int cap_object_info(struct repository *r, struct strvec *keys,
-		    struct packet_reader *request)
+int cap_object_info(struct repository *r, struct packet_reader *request)
 {
 	struct requested_info info;
 	struct packet_writer writer;
diff --git a/protocol-caps.h b/protocol-caps.h
index 0a9f49d..15c4550 100644
--- a/protocol-caps.h
+++ b/protocol-caps.h
@@ -2,9 +2,7 @@
 #define PROTOCOL_CAPS_H
 
 struct repository;
-struct strvec;
 struct packet_reader;
-int cap_object_info(struct repository *r, struct strvec *keys,
-		    struct packet_reader *request);
+int cap_object_info(struct repository *r, struct packet_reader *request);
 
 #endif /* PROTOCOL_CAPS_H */
diff --git a/quote.c b/quote.c
index 8a3a5e3..26719d2 100644
--- a/quote.c
+++ b/quote.c
@@ -471,6 +471,23 @@
 	strbuf_addch(sb, sq);
 }
 
+void perl_quote_buf_with_len(struct strbuf *sb, const char *src, size_t len)
+{
+	const char sq = '\'';
+	const char bq = '\\';
+	const char *c = src;
+	const char *end = src + len;
+
+	strbuf_addch(sb, sq);
+	while (c != end) {
+		if (*c == sq || *c == bq)
+			strbuf_addch(sb, bq);
+		strbuf_addch(sb, *c);
+		c++;
+	}
+	strbuf_addch(sb, sq);
+}
+
 void python_quote_buf(struct strbuf *sb, const char *src)
 {
 	const char sq = '\'';
diff --git a/quote.h b/quote.h
index 049d8dd..87ff458 100644
--- a/quote.h
+++ b/quote.h
@@ -95,6 +95,7 @@
 
 /* quoting as a string literal for other languages */
 void perl_quote_buf(struct strbuf *sb, const char *src);
+void perl_quote_buf_with_len(struct strbuf *sb, const char *src, size_t len);
 void python_quote_buf(struct strbuf *sb, const char *src);
 void tcl_quote_buf(struct strbuf *sb, const char *src);
 void basic_regex_quote_buf(struct strbuf *sb, const char *src);
diff --git a/read-cache.c b/read-cache.c
index 9048ef9..f398659 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -738,7 +738,7 @@
 	int intent_only = flags & ADD_CACHE_INTENT;
 	int add_option = (ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE|
 			  (intent_only ? ADD_CACHE_NEW_ONLY : 0));
-	int hash_flags = HASH_WRITE_OBJECT;
+	unsigned hash_flags = pretend ? 0 : HASH_WRITE_OBJECT;
 	struct object_id oid;
 
 	if (flags & ADD_CACHE_RENORMALIZE)
@@ -849,6 +849,19 @@
 	return xcalloc(1, cache_entry_size(len));
 }
 
+enum verify_path_result {
+	PATH_OK,
+	PATH_INVALID,
+	PATH_DIR_WITH_SEP,
+};
+
+static enum verify_path_result verify_path_internal(const char *, unsigned);
+
+int verify_path(const char *path, unsigned mode)
+{
+	return verify_path_internal(path, mode) == PATH_OK;
+}
+
 struct cache_entry *make_cache_entry(struct index_state *istate,
 				     unsigned int mode,
 				     const struct object_id *oid,
@@ -859,7 +872,7 @@
 	struct cache_entry *ce, *ret;
 	int len;
 
-	if (!verify_path(path, mode)) {
+	if (verify_path_internal(path, mode) == PATH_INVALID) {
 		error(_("invalid path '%s'"), path);
 		return NULL;
 	}
@@ -993,60 +1006,62 @@
 	return 1;
 }
 
-int verify_path(const char *path, unsigned mode)
+static enum verify_path_result verify_path_internal(const char *path,
+						    unsigned mode)
 {
 	char c = 0;
 
 	if (has_dos_drive_prefix(path))
-		return 0;
+		return PATH_INVALID;
 
 	if (!is_valid_path(path))
-		return 0;
+		return PATH_INVALID;
 
 	goto inside;
 	for (;;) {
 		if (!c)
-			return 1;
+			return PATH_OK;
 		if (is_dir_sep(c)) {
 inside:
 			if (protect_hfs) {
 
 				if (is_hfs_dotgit(path))
-					return 0;
+					return PATH_INVALID;
 				if (S_ISLNK(mode)) {
 					if (is_hfs_dotgitmodules(path))
-						return 0;
+						return PATH_INVALID;
 				}
 			}
 			if (protect_ntfs) {
 #if defined GIT_WINDOWS_NATIVE || defined __CYGWIN__
 				if (c == '\\')
-					return 0;
+					return PATH_INVALID;
 #endif
 				if (is_ntfs_dotgit(path))
-					return 0;
+					return PATH_INVALID;
 				if (S_ISLNK(mode)) {
 					if (is_ntfs_dotgitmodules(path))
-						return 0;
+						return PATH_INVALID;
 				}
 			}
 
 			c = *path++;
 			if ((c == '.' && !verify_dotfile(path, mode)) ||
 			    is_dir_sep(c))
-				return 0;
+				return PATH_INVALID;
 			/*
 			 * allow terminating directory separators for
 			 * sparse directory entries.
 			 */
 			if (c == '\0')
-				return S_ISDIR(mode);
+				return S_ISDIR(mode) ? PATH_DIR_WITH_SEP :
+						       PATH_INVALID;
 		} else if (c == '\\' && protect_ntfs) {
 			if (is_ntfs_dotgit(path))
-				return 0;
+				return PATH_INVALID;
 			if (S_ISLNK(mode)) {
 				if (is_ntfs_dotgitmodules(path))
-					return 0;
+					return PATH_INVALID;
 			}
 		}
 
@@ -1349,7 +1364,7 @@
 
 	if (!ok_to_add)
 		return -1;
-	if (!verify_path(ce->name, ce->ce_mode))
+	if (verify_path_internal(ce->name, ce->ce_mode) == PATH_INVALID)
 		return error(_("invalid path '%s'"), ce->name);
 
 	if (!skip_df_check &&
@@ -1944,13 +1959,22 @@
 
 	prepare_repo_settings(r);
 
-	if (r->settings.core_untracked_cache  == UNTRACKED_CACHE_REMOVE) {
+	switch (r->settings.core_untracked_cache) {
+	case UNTRACKED_CACHE_REMOVE:
 		remove_untracked_cache(istate);
-		return;
-	}
-
-	if (r->settings.core_untracked_cache == UNTRACKED_CACHE_WRITE)
+		break;
+	case UNTRACKED_CACHE_WRITE:
 		add_untracked_cache(istate);
+		break;
+	case UNTRACKED_CACHE_KEEP:
+		/*
+		 * Either an explicit "core.untrackedCache=keep", the
+		 * default if "core.untrackedCache" isn't configured,
+		 * or a fallback on an unknown "core.untrackedCache"
+		 * value.
+		 */
+		break;
+	}
 }
 
 static void tweak_split_index(struct index_state *istate)
@@ -2391,9 +2415,21 @@
 	base_path = xstrfmt("%s/sharedindex.%s", gitdir, base_oid_hex);
 	trace2_region_enter_printf("index", "shared/do_read_index",
 				   the_repository, "%s", base_path);
-	ret = do_read_index(split_index->base, base_path, 1);
+	ret = do_read_index(split_index->base, base_path, 0);
 	trace2_region_leave_printf("index", "shared/do_read_index",
 				   the_repository, "%s", base_path);
+	if (!ret) {
+		char *path_copy = xstrdup(path);
+		const char *base_path2 = xstrfmt("%s/sharedindex.%s",
+						 dirname(path_copy),
+						 base_oid_hex);
+		free(path_copy);
+		trace2_region_enter_printf("index", "shared/do_read_index",
+					   the_repository, "%s", base_path2);
+		ret = do_read_index(split_index->base, base_path2, 1);
+		trace2_region_leave_printf("index", "shared/do_read_index",
+					   the_repository, "%s", base_path2);
+	}
 	if (!oideq(&split_index->base_oid, &split_index->base->oid))
 		die(_("broken index, expect %s in %s, got %s"),
 		    base_oid_hex, base_path,
@@ -2812,11 +2848,8 @@
 		}
 	}
 
-	if (!istate->version) {
+	if (!istate->version)
 		istate->version = get_index_format_default(the_repository);
-		if (git_env_bool("GIT_TEST_SPLIT_INDEX", 0))
-			init_split_index(istate);
-	}
 
 	/* demote version 3 to version 2 when the latter suffices */
 	if (istate->version == 3 || istate->version == 2)
@@ -3069,7 +3102,7 @@
 	int ret;
 	int was_full = !istate->sparse_index;
 
-	ret = convert_to_sparse(istate);
+	ret = convert_to_sparse(istate, 0);
 
 	if (ret) {
 		warning(_("failed to convert to a sparse-index"));
@@ -3182,7 +3215,7 @@
 	int ret, was_full = !istate->sparse_index;
 
 	move_cache_to_base_index(istate);
-	convert_to_sparse(istate);
+	convert_to_sparse(istate, 0);
 
 	trace2_region_enter_printf("index", "shared/do_write_index",
 				   the_repository, "%s", get_tempfile_path(*temp));
@@ -3243,7 +3276,7 @@
 int write_locked_index(struct index_state *istate, struct lock_file *lock,
 		       unsigned flags)
 {
-	int new_shared_index, ret;
+	int new_shared_index, ret, test_split_index_env;
 	struct split_index *si = istate->split_index;
 
 	if (git_env_bool("GIT_TEST_CHECK_CACHE_TREE", 0))
@@ -3258,7 +3291,10 @@
 	if (istate->fsmonitor_last_update)
 		fill_fsmonitor_bitmap(istate);
 
-	if (!si || alternate_index_output ||
+	test_split_index_env = git_env_bool("GIT_TEST_SPLIT_INDEX", 0);
+
+	if ((!si && !test_split_index_env) ||
+	    alternate_index_output ||
 	    (istate->cache_changed & ~EXTMASK)) {
 		if (si)
 			oidclr(&si->base_oid);
@@ -3266,10 +3302,15 @@
 		goto out;
 	}
 
-	if (git_env_bool("GIT_TEST_SPLIT_INDEX", 0)) {
-		int v = si->base_oid.hash[0];
-		if ((v & 15) < 6)
+	if (test_split_index_env) {
+		if (!si) {
+			si = init_split_index(istate);
 			istate->cache_changed |= SPLIT_INDEX_ORDERED;
+		} else {
+			int v = si->base_oid.hash[0];
+			if ((v & 15) < 6)
+				istate->cache_changed |= SPLIT_INDEX_ORDERED;
+		}
 	}
 	if (too_many_not_shared_entries(istate))
 		istate->cache_changed |= SPLIT_INDEX_ORDERED;
diff --git a/rebase-interactive.c b/rebase-interactive.c
index b6cbd16..87649d0 100644
--- a/rebase-interactive.c
+++ b/rebase-interactive.c
@@ -226,32 +226,3 @@
 	todo_list_release(&backup);
 	return res;
 }
-
-int check_todo_list_from_file(struct repository *r)
-{
-	struct todo_list old_todo = TODO_LIST_INIT, new_todo = TODO_LIST_INIT;
-	int res = 0;
-
-	if (strbuf_read_file(&new_todo.buf, rebase_path_todo(), 0) < 0) {
-		res = error(_("could not read '%s'."), rebase_path_todo());
-		goto out;
-	}
-
-	if (strbuf_read_file(&old_todo.buf, rebase_path_todo_backup(), 0) < 0) {
-		res = error(_("could not read '%s'."), rebase_path_todo_backup());
-		goto out;
-	}
-
-	res = todo_list_parse_insn_buffer(r, old_todo.buf.buf, &old_todo);
-	if (!res)
-		res = todo_list_parse_insn_buffer(r, new_todo.buf.buf, &new_todo);
-	if (res)
-		fprintf(stderr, _(edit_todo_list_advice));
-	if (!res)
-		res = todo_list_check(&old_todo, &new_todo);
-out:
-	todo_list_release(&old_todo);
-	todo_list_release(&new_todo);
-
-	return res;
-}
diff --git a/rebase-interactive.h b/rebase-interactive.h
index dc2cf0e..7239c60 100644
--- a/rebase-interactive.h
+++ b/rebase-interactive.h
@@ -16,6 +16,4 @@
 int todo_list_check_against_backup(struct repository *r,
 				   struct todo_list *todo_list);
 
-int check_todo_list_from_file(struct repository *r);
-
 #endif
diff --git a/rebase.c b/rebase.c
index f8137d8..6775cdd 100644
--- a/rebase.c
+++ b/rebase.c
@@ -1,5 +1,6 @@
 #include "rebase.h"
 #include "config.h"
+#include "gettext.h"
 
 /*
  * Parses textual value for pull.rebase, branch.<name>.rebase, etc.
@@ -20,12 +21,12 @@
 		return REBASE_FALSE;
 	else if (v > 0)
 		return REBASE_TRUE;
-	else if (!strcmp(value, "preserve") || !strcmp(value, "p"))
-		return REBASE_PRESERVE;
 	else if (!strcmp(value, "merges") || !strcmp(value, "m"))
 		return REBASE_MERGES;
 	else if (!strcmp(value, "interactive") || !strcmp(value, "i"))
 		return REBASE_INTERACTIVE;
+	else if (!strcmp(value, "preserve") || !strcmp(value, "p"))
+		error(_("%s: 'preserve' superseded by 'merges'"), value);
 	/*
 	 * Please update _git_config() in git-completion.bash when you
 	 * add new rebase modes.
diff --git a/rebase.h b/rebase.h
index cc723d4..203b437 100644
--- a/rebase.h
+++ b/rebase.h
@@ -5,7 +5,6 @@
 	REBASE_INVALID = -1,
 	REBASE_FALSE = 0,
 	REBASE_TRUE,
-	REBASE_PRESERVE,
 	REBASE_MERGES,
 	REBASE_INTERACTIVE
 };
diff --git a/ref-filter.c b/ref-filter.c
index 0cfef7b..282cdad 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -144,6 +144,7 @@
 	ATOM_BODY,
 	ATOM_TRAILERS,
 	ATOM_CONTENTS,
+	ATOM_RAW,
 	ATOM_UPSTREAM,
 	ATOM_PUSH,
 	ATOM_SYMREF,
@@ -156,6 +157,7 @@
 	ATOM_IF,
 	ATOM_THEN,
 	ATOM_ELSE,
+	ATOM_REST,
 };
 
 /*
@@ -190,6 +192,9 @@
 			unsigned int nlines;
 		} contents;
 		struct {
+			enum { RAW_BARE, RAW_LENGTH } option;
+		} raw_data;
+		struct {
 			cmp_status cmp_status;
 			const char *str;
 		} if_then_else;
@@ -223,7 +228,7 @@
 	return ret;
 }
 
-static int color_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int color_atom_parser(struct ref_format *format, struct used_atom *atom,
 			     const char *color_value, struct strbuf *err)
 {
 	if (!color_value)
@@ -261,7 +266,7 @@
 	return 0;
 }
 
-static int remote_ref_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int remote_ref_atom_parser(struct ref_format *format, struct used_atom *atom,
 				  const char *arg, struct strbuf *err)
 {
 	struct string_list params = STRING_LIST_INIT_DUP;
@@ -308,7 +313,7 @@
 	return 0;
 }
 
-static int objecttype_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int objecttype_atom_parser(struct ref_format *format, struct used_atom *atom,
 				  const char *arg, struct strbuf *err)
 {
 	if (arg)
@@ -320,7 +325,7 @@
 	return 0;
 }
 
-static int objectsize_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int objectsize_atom_parser(struct ref_format *format, struct used_atom *atom,
 				  const char *arg, struct strbuf *err)
 {
 	if (!arg) {
@@ -340,7 +345,7 @@
 	return 0;
 }
 
-static int deltabase_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int deltabase_atom_parser(struct ref_format *format, struct used_atom *atom,
 				 const char *arg, struct strbuf *err)
 {
 	if (arg)
@@ -352,7 +357,7 @@
 	return 0;
 }
 
-static int body_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int body_atom_parser(struct ref_format *format, struct used_atom *atom,
 			    const char *arg, struct strbuf *err)
 {
 	if (arg)
@@ -361,7 +366,7 @@
 	return 0;
 }
 
-static int subject_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int subject_atom_parser(struct ref_format *format, struct used_atom *atom,
 			       const char *arg, struct strbuf *err)
 {
 	if (!arg)
@@ -373,7 +378,7 @@
 	return 0;
 }
 
-static int trailers_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int trailers_atom_parser(struct ref_format *format, struct used_atom *atom,
 				const char *arg, struct strbuf *err)
 {
 	atom->u.contents.trailer_opts.no_divider = 1;
@@ -399,7 +404,7 @@
 	return 0;
 }
 
-static int contents_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int contents_atom_parser(struct ref_format *format, struct used_atom *atom,
 				const char *arg, struct strbuf *err)
 {
 	if (!arg)
@@ -427,7 +432,19 @@
 	return 0;
 }
 
-static int oid_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int raw_atom_parser(struct ref_format *format, struct used_atom *atom,
+				const char *arg, struct strbuf *err)
+{
+	if (!arg)
+		atom->u.raw_data.option = RAW_BARE;
+	else if (!strcmp(arg, "size"))
+		atom->u.raw_data.option = RAW_LENGTH;
+	else
+		return strbuf_addf_ret(err, -1, _("unrecognized %%(raw) argument: %s"), arg);
+	return 0;
+}
+
+static int oid_atom_parser(struct ref_format *format, struct used_atom *atom,
 			   const char *arg, struct strbuf *err)
 {
 	if (!arg)
@@ -446,7 +463,7 @@
 	return 0;
 }
 
-static int person_email_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int person_email_atom_parser(struct ref_format *format, struct used_atom *atom,
 				    const char *arg, struct strbuf *err)
 {
 	if (!arg)
@@ -460,7 +477,7 @@
 	return 0;
 }
 
-static int refname_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int refname_atom_parser(struct ref_format *format, struct used_atom *atom,
 			       const char *arg, struct strbuf *err)
 {
 	return refname_atom_parser_internal(&atom->u.refname, arg, atom->name, err);
@@ -477,7 +494,7 @@
 	return -1;
 }
 
-static int align_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int align_atom_parser(struct ref_format *format, struct used_atom *atom,
 			     const char *arg, struct strbuf *err)
 {
 	struct align *align = &atom->u.align;
@@ -529,7 +546,7 @@
 	return 0;
 }
 
-static int if_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int if_atom_parser(struct ref_format *format, struct used_atom *atom,
 			  const char *arg, struct strbuf *err)
 {
 	if (!arg) {
@@ -544,7 +561,16 @@
 	return 0;
 }
 
-static int head_atom_parser(const struct ref_format *format, struct used_atom *atom,
+static int rest_atom_parser(struct ref_format *format, struct used_atom *atom,
+			    const char *arg, struct strbuf *err)
+{
+	if (arg)
+		return strbuf_addf_ret(err, -1, _("%%(rest) does not take arguments"));
+	format->use_rest = 1;
+	return 0;
+}
+
+static int head_atom_parser(struct ref_format *format, struct used_atom *atom,
 			    const char *arg, struct strbuf *unused_err)
 {
 	atom->u.head = resolve_refdup("HEAD", RESOLVE_REF_READING, NULL, NULL);
@@ -555,7 +581,7 @@
 	const char *name;
 	info_source source;
 	cmp_type cmp_type;
-	int (*parser)(const struct ref_format *format, struct used_atom *atom,
+	int (*parser)(struct ref_format *format, struct used_atom *atom,
 		      const char *arg, struct strbuf *err);
 } valid_atom[] = {
 	[ATOM_REFNAME] = { "refname", SOURCE_NONE, FIELD_STR, refname_atom_parser },
@@ -587,6 +613,7 @@
 	[ATOM_BODY] = { "body", SOURCE_OBJ, FIELD_STR, body_atom_parser },
 	[ATOM_TRAILERS] = { "trailers", SOURCE_OBJ, FIELD_STR, trailers_atom_parser },
 	[ATOM_CONTENTS] = { "contents", SOURCE_OBJ, FIELD_STR, contents_atom_parser },
+	[ATOM_RAW] = { "raw", SOURCE_OBJ, FIELD_STR, raw_atom_parser },
 	[ATOM_UPSTREAM] = { "upstream", SOURCE_NONE, FIELD_STR, remote_ref_atom_parser },
 	[ATOM_PUSH] = { "push", SOURCE_NONE, FIELD_STR, remote_ref_atom_parser },
 	[ATOM_SYMREF] = { "symref", SOURCE_NONE, FIELD_STR, refname_atom_parser },
@@ -599,13 +626,14 @@
 	[ATOM_IF] = { "if", SOURCE_NONE, FIELD_STR, if_atom_parser },
 	[ATOM_THEN] = { "then", SOURCE_NONE },
 	[ATOM_ELSE] = { "else", SOURCE_NONE },
+	[ATOM_REST] = { "rest", SOURCE_NONE, FIELD_STR, rest_atom_parser },
 	/*
 	 * Please update $__git_ref_fieldlist in git-completion.bash
 	 * when you add new atoms
 	 */
 };
 
-#define REF_FORMATTING_STATE_INIT  { 0, NULL }
+#define REF_FORMATTING_STATE_INIT  { 0 }
 
 struct ref_formatting_stack {
 	struct ref_formatting_stack *prev;
@@ -621,16 +649,23 @@
 
 struct atom_value {
 	const char *s;
+	ssize_t s_size;
 	int (*handler)(struct atom_value *atomv, struct ref_formatting_state *state,
 		       struct strbuf *err);
 	uintmax_t value; /* used for sorting when not FIELD_STR */
 	struct used_atom *atom;
 };
 
+#define ATOM_SIZE_UNSPECIFIED (-1)
+
+#define ATOM_VALUE_INIT { \
+	.s_size = ATOM_SIZE_UNSPECIFIED \
+}
+
 /*
  * Used to parse format string and sort specifiers
  */
-static int parse_ref_filter_atom(const struct ref_format *format,
+static int parse_ref_filter_atom(struct ref_format *format,
 				 const char *atom, const char *ep,
 				 struct strbuf *err)
 {
@@ -645,13 +680,6 @@
 		return strbuf_addf_ret(err, -1, _("malformed field name: %.*s"),
 				       (int)(ep-atom), atom);
 
-	/* Do we have the atom already used elsewhere? */
-	for (i = 0; i < used_atom_cnt; i++) {
-		int len = strlen(used_atom[i].name);
-		if (len == ep - atom && !memcmp(used_atom[i].name, atom, len))
-			return i;
-	}
-
 	/*
 	 * If the atom name has a colon, strip it and everything after
 	 * it off - it specifies the format for this entry, and
@@ -661,6 +689,13 @@
 	arg = memchr(sp, ':', ep - sp);
 	atom_len = (arg ? arg : ep) - sp;
 
+	/* Do we have the atom already used elsewhere? */
+	for (i = 0; i < used_atom_cnt; i++) {
+		int len = strlen(used_atom[i].name);
+		if (len == ep - atom && !memcmp(used_atom[i].name, atom, len))
+			return i;
+	}
+
 	/* Is the atom a valid one? */
 	for (i = 0; i < ARRAY_SIZE(valid_atom); i++) {
 		int len = strlen(valid_atom[i].name);
@@ -710,17 +745,23 @@
 	return at;
 }
 
-static void quote_formatting(struct strbuf *s, const char *str, int quote_style)
+static void quote_formatting(struct strbuf *s, const char *str, ssize_t len, int quote_style)
 {
 	switch (quote_style) {
 	case QUOTE_NONE:
-		strbuf_addstr(s, str);
+		if (len < 0)
+			strbuf_addstr(s, str);
+		else
+			strbuf_add(s, str, len);
 		break;
 	case QUOTE_SHELL:
 		sq_quote_buf(s, str);
 		break;
 	case QUOTE_PERL:
-		perl_quote_buf(s, str);
+		if (len < 0)
+			perl_quote_buf(s, str);
+		else
+			perl_quote_buf_with_len(s, str, len);
 		break;
 	case QUOTE_PYTHON:
 		python_quote_buf(s, str);
@@ -741,9 +782,11 @@
 	 * encountered.
 	 */
 	if (!state->stack->prev)
-		quote_formatting(&state->stack->output, v->s, state->quote_style);
-	else
+		quote_formatting(&state->stack->output, v->s, v->s_size, state->quote_style);
+	else if (v->s_size < 0)
 		strbuf_addstr(&state->stack->output, v->s);
+	else
+		strbuf_add(&state->stack->output, v->s, v->s_size);
 	return 0;
 }
 
@@ -843,21 +886,23 @@
 	return 0;
 }
 
-static int is_empty(const char *s)
+static int is_empty(struct strbuf *buf)
 {
-	while (*s != '\0') {
-		if (!isspace(*s))
-			return 0;
-		s++;
-	}
-	return 1;
-}
+	const char *cur = buf->buf;
+	const char *end = buf->buf + buf->len;
+
+	while (cur != end && (isspace(*cur)))
+		cur++;
+
+	return cur == end;
+ }
 
 static int then_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
 			     struct strbuf *err)
 {
 	struct ref_formatting_stack *cur = state->stack;
 	struct if_then_else *if_then_else = NULL;
+	size_t str_len = 0;
 
 	if (cur->at_end == if_then_else_handler)
 		if_then_else = (struct if_then_else *)cur->at_end_data;
@@ -868,18 +913,22 @@
 	if (if_then_else->else_atom_seen)
 		return strbuf_addf_ret(err, -1, _("format: %%(then) atom used after %%(else)"));
 	if_then_else->then_atom_seen = 1;
+	if (if_then_else->str)
+		str_len = strlen(if_then_else->str);
 	/*
 	 * If the 'equals' or 'notequals' attribute is used then
 	 * perform the required comparison. If not, only non-empty
 	 * strings satisfy the 'if' condition.
 	 */
 	if (if_then_else->cmp_status == COMPARE_EQUAL) {
-		if (!strcmp(if_then_else->str, cur->output.buf))
+		if (str_len == cur->output.len &&
+		    !memcmp(if_then_else->str, cur->output.buf, cur->output.len))
 			if_then_else->condition_satisfied = 1;
 	} else if (if_then_else->cmp_status == COMPARE_UNEQUAL) {
-		if (strcmp(if_then_else->str, cur->output.buf))
+		if (str_len != cur->output.len ||
+		    memcmp(if_then_else->str, cur->output.buf, cur->output.len))
 			if_then_else->condition_satisfied = 1;
-	} else if (cur->output.len && !is_empty(cur->output.buf))
+	} else if (cur->output.len && !is_empty(&cur->output))
 		if_then_else->condition_satisfied = 1;
 	strbuf_reset(&cur->output);
 	return 0;
@@ -925,7 +974,7 @@
 	 * only on the topmost supporting atom.
 	 */
 	if (!current->prev->prev) {
-		quote_formatting(&s, current->output.buf, state->quote_style);
+		quote_formatting(&s, current->output.buf, current->output.len, state->quote_style);
 		strbuf_swap(&current->output, &s);
 	}
 	strbuf_release(&s);
@@ -955,6 +1004,11 @@
 	return NULL;
 }
 
+static int reject_atom(enum atom_type atom_type)
+{
+	return atom_type == ATOM_REST;
+}
+
 /*
  * Make sure the format string is well formed, and parse out
  * the used atoms.
@@ -975,6 +1029,16 @@
 		at = parse_ref_filter_atom(format, sp + 2, ep, &err);
 		if (at < 0)
 			die("%s", err.buf);
+		if (reject_atom(used_atom[at].atom_type))
+			die(_("this command reject atom %%(%.*s)"), (int)(ep - sp - 2), sp + 2);
+
+		if ((format->quote_style == QUOTE_PYTHON ||
+		     format->quote_style == QUOTE_SHELL ||
+		     format->quote_style == QUOTE_TCL) &&
+		     used_atom[at].atom_type == ATOM_RAW &&
+		     used_atom[at].u.raw_data.option == RAW_BARE)
+			die(_("--format=%.*s cannot be used with"
+			      "--python, --shell, --tcl"), (int)(ep - sp - 2), sp + 2);
 		cp = ep + 1;
 
 		if (skip_prefix(used_atom[at].name, "color:", &color))
@@ -1357,25 +1421,42 @@
 }
 
 /* See grab_values */
-static void grab_sub_body_contents(struct atom_value *val, int deref, void *buf)
+static void grab_sub_body_contents(struct atom_value *val, int deref, struct expand_data *data)
 {
 	int i;
 	const char *subpos = NULL, *bodypos = NULL, *sigpos = NULL;
 	size_t sublen = 0, bodylen = 0, nonsiglen = 0, siglen = 0;
+	void *buf = data->content;
 
 	for (i = 0; i < used_atom_cnt; i++) {
 		struct used_atom *atom = &used_atom[i];
 		const char *name = atom->name;
 		struct atom_value *v = &val[i];
+		enum atom_type atom_type = atom->atom_type;
 
 		if (!!deref != (*name == '*'))
 			continue;
 		if (deref)
 			name++;
-		if (strcmp(name, "body") &&
-		    !starts_with(name, "subject") &&
-		    !starts_with(name, "trailers") &&
-		    !starts_with(name, "contents"))
+
+		if (atom_type == ATOM_RAW) {
+			unsigned long buf_size = data->size;
+
+			if (atom->u.raw_data.option == RAW_BARE) {
+				v->s = xmemdupz(buf, buf_size);
+				v->s_size = buf_size;
+			} else if (atom->u.raw_data.option == RAW_LENGTH) {
+				v->s = xstrfmt("%"PRIuMAX, (uintmax_t)buf_size);
+			}
+			continue;
+		}
+
+		if ((data->type != OBJ_TAG &&
+		     data->type != OBJ_COMMIT) ||
+		    (strcmp(name, "body") &&
+		     !starts_with(name, "subject") &&
+		     !starts_with(name, "trailers") &&
+		     !starts_with(name, "contents")))
 			continue;
 		if (!subpos)
 			find_subpos(buf,
@@ -1439,25 +1520,29 @@
  * pointed at by the ref itself; otherwise it is the object the
  * ref (which is a tag) refers to.
  */
-static void grab_values(struct atom_value *val, int deref, struct object *obj, void *buf)
+static void grab_values(struct atom_value *val, int deref, struct object *obj, struct expand_data *data)
 {
+	void *buf = data->content;
+
 	switch (obj->type) {
 	case OBJ_TAG:
 		grab_tag_values(val, deref, obj);
-		grab_sub_body_contents(val, deref, buf);
+		grab_sub_body_contents(val, deref, data);
 		grab_person("tagger", val, deref, buf);
 		break;
 	case OBJ_COMMIT:
 		grab_commit_values(val, deref, obj);
-		grab_sub_body_contents(val, deref, buf);
+		grab_sub_body_contents(val, deref, data);
 		grab_person("author", val, deref, buf);
 		grab_person("committer", val, deref, buf);
 		break;
 	case OBJ_TREE:
 		/* grab_tree_values(val, deref, obj, buf, sz); */
+		grab_sub_body_contents(val, deref, data);
 		break;
 	case OBJ_BLOB:
 		/* grab_blob_values(val, deref, obj, buf, sz); */
+		grab_sub_body_contents(val, deref, data);
 		break;
 	default:
 		die("Eh?  Object of type %d?", obj->type);
@@ -1679,7 +1764,7 @@
 			return strbuf_addf_ret(err, -1, _("parse_object_buffer failed on %s for %s"),
 					       oid_to_hex(&oi->oid), ref->refname);
 		}
-		grab_values(ref->value, deref, *obj, oi->content);
+		grab_values(ref->value, deref, *obj, oi);
 	}
 
 	grab_common_values(ref->value, deref, oi);
@@ -1761,6 +1846,7 @@
 		const char *refname;
 		struct branch *branch = NULL;
 
+		v->s_size = ATOM_SIZE_UNSPECIFIED;
 		v->handler = append_atom;
 		v->atom = atom;
 
@@ -1864,6 +1950,12 @@
 			v->handler = else_atom_handler;
 			v->s = xstrdup("");
 			continue;
+		} else if (atom_type == ATOM_REST) {
+			if (ref->rest)
+				v->s = xstrdup(ref->rest);
+			else
+				v->s = xstrdup("");
+			continue;
 		} else
 			continue;
 
@@ -2008,8 +2100,7 @@
  */
 static int for_each_fullref_in_pattern(struct ref_filter *filter,
 				       each_ref_fn cb,
-				       void *cb_data,
-				       int broken)
+				       void *cb_data)
 {
 	if (!filter->match_as_path) {
 		/*
@@ -2017,7 +2108,7 @@
 		 * prefixes like "refs/heads/" etc. are stripped off,
 		 * so we have to look at everything:
 		 */
-		return for_each_fullref_in("", cb, cb_data, broken);
+		return for_each_fullref_in("", cb, cb_data);
 	}
 
 	if (filter->ignore_case) {
@@ -2026,16 +2117,16 @@
 		 * so just return everything and let the caller
 		 * sort it out.
 		 */
-		return for_each_fullref_in("", cb, cb_data, broken);
+		return for_each_fullref_in("", cb, cb_data);
 	}
 
 	if (!filter->name_patterns[0]) {
 		/* no patterns; we have to look at everything */
-		return for_each_fullref_in("", cb, cb_data, broken);
+		return for_each_fullref_in("", cb, cb_data);
 	}
 
 	return for_each_fullref_in_prefixes(NULL, filter->name_patterns,
-					    cb, cb_data, broken);
+					    cb, cb_data);
 }
 
 /*
@@ -2081,6 +2172,7 @@
 
 	FLEX_ALLOC_STR(ref, refname, refname);
 	oidcpy(&ref->objectname, oid);
+	ref->rest = NULL;
 
 	return ref;
 }
@@ -2312,13 +2404,10 @@
 {
 	struct ref_filter_cbdata ref_cbdata;
 	int ret = 0;
-	unsigned int broken = 0;
 
 	ref_cbdata.array = array;
 	ref_cbdata.filter = filter;
 
-	if (type & FILTER_REFS_INCLUDE_BROKEN)
-		broken = 1;
 	filter->kind = type & FILTER_REFS_KIND_MASK;
 
 	init_contains_cache(&ref_cbdata.contains_cache);
@@ -2335,13 +2424,13 @@
 		 * of filter_ref_kind().
 		 */
 		if (filter->kind == FILTER_REFS_BRANCHES)
-			ret = for_each_fullref_in("refs/heads/", ref_filter_handler, &ref_cbdata, broken);
+			ret = for_each_fullref_in("refs/heads/", ref_filter_handler, &ref_cbdata);
 		else if (filter->kind == FILTER_REFS_REMOTES)
-			ret = for_each_fullref_in("refs/remotes/", ref_filter_handler, &ref_cbdata, broken);
+			ret = for_each_fullref_in("refs/remotes/", ref_filter_handler, &ref_cbdata);
 		else if (filter->kind == FILTER_REFS_TAGS)
-			ret = for_each_fullref_in("refs/tags/", ref_filter_handler, &ref_cbdata, broken);
+			ret = for_each_fullref_in("refs/tags/", ref_filter_handler, &ref_cbdata);
 		else if (filter->kind & FILTER_REFS_ALL)
-			ret = for_each_fullref_in_pattern(filter, ref_filter_handler, &ref_cbdata, broken);
+			ret = for_each_fullref_in_pattern(filter, ref_filter_handler, &ref_cbdata);
 		if (!ret && (filter->kind & FILTER_REFS_DETACHED_HEAD))
 			head_ref(ref_filter_handler, &ref_cbdata);
 	}
@@ -2368,6 +2457,19 @@
 	return 0;
 }
 
+static int memcasecmp(const void *vs1, const void *vs2, size_t n)
+{
+	const char *s1 = vs1, *s2 = vs2;
+	const char *end = s1 + n;
+
+	for (; s1 < end; s1++, s2++) {
+		int diff = tolower(*s1) - tolower(*s2);
+		if (diff)
+			return diff;
+	}
+	return 0;
+}
+
 static int cmp_ref_sorting(struct ref_sorting *s, struct ref_array_item *a, struct ref_array_item *b)
 {
 	struct atom_value *va, *vb;
@@ -2388,10 +2490,29 @@
 	} else if (s->sort_flags & REF_SORTING_VERSION) {
 		cmp = versioncmp(va->s, vb->s);
 	} else if (cmp_type == FIELD_STR) {
-		int (*cmp_fn)(const char *, const char *);
-		cmp_fn = s->sort_flags & REF_SORTING_ICASE
-			? strcasecmp : strcmp;
-		cmp = cmp_fn(va->s, vb->s);
+		if (va->s_size < 0 && vb->s_size < 0) {
+			int (*cmp_fn)(const char *, const char *);
+			cmp_fn = s->sort_flags & REF_SORTING_ICASE
+				? strcasecmp : strcmp;
+			cmp = cmp_fn(va->s, vb->s);
+		} else {
+			size_t a_size = va->s_size < 0 ?
+					strlen(va->s) : va->s_size;
+			size_t b_size = vb->s_size < 0 ?
+					strlen(vb->s) : vb->s_size;
+			int (*cmp_fn)(const void *, const void *, size_t);
+			cmp_fn = s->sort_flags & REF_SORTING_ICASE
+				? memcasecmp : memcmp;
+
+			cmp = cmp_fn(va->s, vb->s, b_size > a_size ?
+				     a_size : b_size);
+			if (!cmp) {
+				if (a_size > b_size)
+					cmp = 1;
+				else if (a_size < b_size)
+					cmp = -1;
+			}
+		}
 	} else {
 		if (va->value < vb->value)
 			cmp = -1;
@@ -2461,9 +2582,9 @@
 }
 
 int format_ref_array_item(struct ref_array_item *info,
-			   const struct ref_format *format,
-			   struct strbuf *final_buf,
-			   struct strbuf *error_buf)
+			  struct ref_format *format,
+			  struct strbuf *final_buf,
+			  struct strbuf *error_buf)
 {
 	const char *cp, *sp, *ep;
 	struct ref_formatting_state state = REF_FORMATTING_STATE_INIT;
@@ -2490,7 +2611,7 @@
 		append_literal(cp, sp, &state);
 	}
 	if (format->need_color_reset_at_eol) {
-		struct atom_value resetv;
+		struct atom_value resetv = ATOM_VALUE_INIT;
 		resetv.s = GIT_COLOR_RESET;
 		if (append_atom(&resetv, &state, error_buf)) {
 			pop_stack_element(&state.stack);
@@ -2507,7 +2628,7 @@
 }
 
 void pretty_print_ref(const char *name, const struct object_id *oid,
-		      const struct ref_format *format)
+		      struct ref_format *format)
 {
 	struct ref_array_item *ref_item;
 	struct strbuf output = STRBUF_INIT;
@@ -2584,6 +2705,15 @@
 	return 0;
 }
 
+void ref_sorting_release(struct ref_sorting *sorting)
+{
+	while (sorting) {
+		struct ref_sorting *next = sorting->next;
+		free(sorting);
+		sorting = next;
+	}
+}
+
 int parse_opt_merge_filter(const struct option *opt, const char *arg, int unset)
 {
 	struct ref_filter *rf = opt->value;
diff --git a/ref-filter.h b/ref-filter.h
index baf72a7..6228458 100644
--- a/ref-filter.h
+++ b/ref-filter.h
@@ -13,7 +13,6 @@
 #define QUOTE_PYTHON 4
 #define QUOTE_TCL 8
 
-#define FILTER_REFS_INCLUDE_BROKEN 0x0001
 #define FILTER_REFS_TAGS           0x0002
 #define FILTER_REFS_BRANCHES       0x0004
 #define FILTER_REFS_REMOTES        0x0008
@@ -38,6 +37,7 @@
 
 struct ref_array_item {
 	struct object_id objectname;
+	const char *rest;
 	int flag;
 	unsigned int kind;
 	const char *symref;
@@ -76,14 +76,16 @@
 	 * verify_ref_format() afterwards to finalize.
 	 */
 	const char *format;
+	const char *rest;
 	int quote_style;
+	int use_rest;
 	int use_color;
 
 	/* Internal state to ref-filter */
 	int need_color_reset_at_eol;
 };
 
-#define REF_FORMAT_INIT { NULL, 0, -1 }
+#define REF_FORMAT_INIT { .use_color = -1 }
 
 /*  Macros for checking --merged and --no-merged options */
 #define _OPT_MERGED_NO_MERGED(option, filter, h) \
@@ -116,7 +118,7 @@
 void ref_sorting_set_sort_flags_all(struct ref_sorting *sorting, unsigned int mask, int on);
 /*  Based on the given format and quote_style, fill the strbuf */
 int format_ref_array_item(struct ref_array_item *info,
-			  const struct ref_format *format,
+			  struct ref_format *format,
 			  struct strbuf *final_buf,
 			  struct strbuf *error_buf);
 /*  Parse a single sort specifier and add it to the list */
@@ -125,6 +127,8 @@
 int parse_opt_ref_sorting(const struct option *opt, const char *arg, int unset);
 /*  Default sort option based on refname */
 struct ref_sorting *ref_default_sorting(void);
+/* Release a "struct ref_sorting" */
+void ref_sorting_release(struct ref_sorting *);
 /*  Function to parse --merged and --no-merged options */
 int parse_opt_merge_filter(const struct option *opt, const char *arg, int unset);
 /*  Get the current HEAD's description */
@@ -137,7 +141,7 @@
  * name must be a fully qualified refname.
  */
 void pretty_print_ref(const char *name, const struct object_id *oid,
-		      const struct ref_format *format);
+		      struct ref_format *format);
 
 /*
  * Push a single ref onto the array; this can be used to construct your own
diff --git a/reflog-walk.c b/reflog-walk.c
index e9cd328..8ac4b28 100644
--- a/reflog-walk.c
+++ b/reflog-walk.c
@@ -158,10 +158,9 @@
 		}
 		reflogs = read_complete_reflog(branch);
 		if (!reflogs || reflogs->nr == 0) {
-			struct object_id oid;
 			char *b;
 			int ret = dwim_log(branch, strlen(branch),
-					   &oid, &b);
+					   NULL, &b);
 			if (ret > 1)
 				free(b);
 			else if (ret == 1) {
diff --git a/refs.c b/refs.c
index 8b9f7c3..d7cc0a2 100644
--- a/refs.c
+++ b/refs.c
@@ -10,6 +10,7 @@
 #include "refs.h"
 #include "refs/refs-internal.h"
 #include "run-command.h"
+#include "hook.h"
 #include "object-store.h"
 #include "object.h"
 #include "tag.h"
@@ -33,11 +34,6 @@
 	return NULL;
 }
 
-int ref_storage_backend_exists(const char *name)
-{
-	return find_ref_storage_backend(name) != NULL;
-}
-
 /*
  * How to handle various characters in refnames:
  * 0: An acceptable character for refs
@@ -255,12 +251,13 @@
  * does not exist, emit a warning and return false.
  */
 int ref_resolves_to_object(const char *refname,
+			   struct repository *repo,
 			   const struct object_id *oid,
 			   unsigned int flags)
 {
 	if (flags & REF_ISBROKEN)
 		return 0;
-	if (!has_object_file(oid)) {
+	if (!repo_has_object_file(repo, oid)) {
 		error(_("%s does not point to a valid object!"), refname);
 		return 0;
 	}
@@ -698,7 +695,7 @@
 		strbuf_addf(&path, *p, len, str);
 		ref = refs_resolve_ref_unsafe(refs, path.buf,
 					      RESOLVE_REF_READING,
-					      &hash, NULL);
+					      oid ? &hash : NULL, NULL);
 		if (!ref)
 			continue;
 		if (refs_reflog_exists(refs, path.buf))
@@ -710,7 +707,8 @@
 			continue;
 		if (!logs_found++) {
 			*log = xstrdup(it);
-			oidcpy(oid, &hash);
+			if (oid)
+				oidcpy(oid, &hash);
 		}
 		if (!warn_ambiguous_refs)
 			break;
@@ -1413,14 +1411,21 @@
 
 struct ref_iterator *refs_ref_iterator_begin(
 		struct ref_store *refs,
-		const char *prefix, int trim, int flags)
+		const char *prefix, int trim,
+		enum do_for_each_ref_flags flags)
 {
 	struct ref_iterator *iter;
 
-	if (ref_paranoia < 0)
-		ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 0);
-	if (ref_paranoia)
-		flags |= DO_FOR_EACH_INCLUDE_BROKEN;
+	if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
+		static int ref_paranoia = -1;
+
+		if (ref_paranoia < 0)
+			ref_paranoia = git_env_bool("GIT_REF_PARANOIA", 1);
+		if (ref_paranoia) {
+			flags |= DO_FOR_EACH_INCLUDE_BROKEN;
+			flags |= DO_FOR_EACH_OMIT_DANGLING_SYMREFS;
+		}
+	}
 
 	iter = refs->be->iterator_begin(refs, prefix, flags);
 
@@ -1479,7 +1484,8 @@
 }
 
 static int do_for_each_ref(struct ref_store *refs, const char *prefix,
-			   each_ref_fn fn, int trim, int flags, void *cb_data)
+			   each_ref_fn fn, int trim,
+			   enum do_for_each_ref_flags flags, void *cb_data)
 {
 	struct ref_iterator *iter;
 	struct do_for_each_ref_help hp = { fn, cb_data };
@@ -1514,25 +1520,16 @@
 	return refs_for_each_ref_in(get_main_ref_store(the_repository), prefix, fn, cb_data);
 }
 
-int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data, unsigned int broken)
+int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data)
 {
-	unsigned int flag = 0;
-
-	if (broken)
-		flag = DO_FOR_EACH_INCLUDE_BROKEN;
 	return do_for_each_ref(get_main_ref_store(the_repository),
-			       prefix, fn, 0, flag, cb_data);
+			       prefix, fn, 0, 0, cb_data);
 }
 
 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
-			     each_ref_fn fn, void *cb_data,
-			     unsigned int broken)
+			     each_ref_fn fn, void *cb_data)
 {
-	unsigned int flag = 0;
-
-	if (broken)
-		flag = DO_FOR_EACH_INCLUDE_BROKEN;
-	return do_for_each_ref(refs, prefix, fn, 0, flag, cb_data);
+	return do_for_each_ref(refs, prefix, fn, 0, 0, cb_data);
 }
 
 int for_each_replace_ref(struct repository *r, each_repo_ref_fn fn, void *cb_data)
@@ -1624,8 +1621,7 @@
 
 int for_each_fullref_in_prefixes(const char *namespace,
 				 const char **patterns,
-				 each_ref_fn fn, void *cb_data,
-				 unsigned int broken)
+				 each_ref_fn fn, void *cb_data)
 {
 	struct string_list prefixes = STRING_LIST_INIT_DUP;
 	struct string_list_item *prefix;
@@ -1640,7 +1636,7 @@
 
 	for_each_string_list_item(prefix, &prefixes) {
 		strbuf_addstr(&buf, prefix->string);
-		ret = for_each_fullref_in(buf.buf, fn, cb_data, broken);
+		ret = for_each_fullref_in(buf.buf, fn, cb_data);
 		if (ret)
 			break;
 		strbuf_setlen(&buf, namespace_len);
@@ -1681,7 +1677,7 @@
 	}
 
 	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent,
-					   type);
+					   type, &errno);
 }
 
 /* This function needs to return a meaningful errno on failure */
@@ -1875,7 +1871,8 @@
  * Create, record, and return a ref_store instance for the specified
  * gitdir.
  */
-static struct ref_store *ref_store_init(const char *gitdir,
+static struct ref_store *ref_store_init(struct repository *repo,
+					const char *gitdir,
 					unsigned int flags)
 {
 	const char *be_name = "files";
@@ -1885,7 +1882,7 @@
 	if (!be)
 		BUG("reference backend %s is unknown", be_name);
 
-	refs = be->init(gitdir, flags);
+	refs = be->init(repo, gitdir, flags);
 	return refs;
 }
 
@@ -1897,7 +1894,7 @@
 	if (!r->gitdir)
 		BUG("attempting to get main_ref_store outside of repository");
 
-	r->refs_private = ref_store_init(r->gitdir, REF_STORE_ALL_CAPS);
+	r->refs_private = ref_store_init(r, r->gitdir, REF_STORE_ALL_CAPS);
 	r->refs_private = maybe_debug_wrap_ref_store(r->gitdir, r->refs_private);
 	return r->refs_private;
 }
@@ -1927,6 +1924,7 @@
 	struct ref_store *refs;
 	char *to_free = NULL;
 	size_t len;
+	struct repository *subrepo;
 
 	if (!submodule)
 		return NULL;
@@ -1952,8 +1950,19 @@
 	if (submodule_to_gitdir(&submodule_sb, submodule))
 		goto done;
 
-	/* assume that add_submodule_odb() has been called */
-	refs = ref_store_init(submodule_sb.buf,
+	subrepo = xmalloc(sizeof(*subrepo));
+	/*
+	 * NEEDSWORK: Make get_submodule_ref_store() work with arbitrary
+	 * superprojects other than the_repository. This probably should be
+	 * done by making it take a struct repository * parameter instead of a
+	 * submodule path.
+	 */
+	if (repo_submodule_init(subrepo, the_repository, submodule,
+				null_oid())) {
+		free(subrepo);
+		goto done;
+	}
+	refs = ref_store_init(subrepo, submodule_sb.buf,
 			      REF_STORE_READ | REF_STORE_ODB);
 	register_ref_store_map(&submodule_ref_stores, "submodule",
 			       refs, submodule);
@@ -1979,10 +1988,12 @@
 		return refs;
 
 	if (wt->id)
-		refs = ref_store_init(git_common_path("worktrees/%s", wt->id),
+		refs = ref_store_init(the_repository,
+				      git_common_path("worktrees/%s", wt->id),
 				      REF_STORE_ALL_CAPS);
 	else
-		refs = ref_store_init(get_git_common_dir(),
+		refs = ref_store_init(the_repository,
+				      get_git_common_dir(),
 				      REF_STORE_ALL_CAPS);
 
 	if (refs)
@@ -2370,19 +2381,19 @@
 }
 
 int refs_reflog_expire(struct ref_store *refs,
-		       const char *refname, const struct object_id *oid,
+		       const char *refname,
 		       unsigned int flags,
 		       reflog_expiry_prepare_fn prepare_fn,
 		       reflog_expiry_should_prune_fn should_prune_fn,
 		       reflog_expiry_cleanup_fn cleanup_fn,
 		       void *policy_cb_data)
 {
-	return refs->be->reflog_expire(refs, refname, oid, flags,
+	return refs->be->reflog_expire(refs, refname, flags,
 				       prepare_fn, should_prune_fn,
 				       cleanup_fn, policy_cb_data);
 }
 
-int reflog_expire(const char *refname, const struct object_id *oid,
+int reflog_expire(const char *refname,
 		  unsigned int flags,
 		  reflog_expiry_prepare_fn prepare_fn,
 		  reflog_expiry_should_prune_fn should_prune_fn,
@@ -2390,7 +2401,7 @@
 		  void *policy_cb_data)
 {
 	return refs_reflog_expire(get_main_ref_store(the_repository),
-				  refname, oid, flags,
+				  refname, flags,
 				  prepare_fn, should_prune_fn,
 				  cleanup_fn, policy_cb_data);
 }
diff --git a/refs.h b/refs.h
index 48970df..d5099d4 100644
--- a/refs.h
+++ b/refs.h
@@ -342,10 +342,8 @@
 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);
 
 int refs_for_each_fullref_in(struct ref_store *refs, const char *prefix,
-			     each_ref_fn fn, void *cb_data,
-			     unsigned int broken);
-int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data,
-			unsigned int broken);
+			     each_ref_fn fn, void *cb_data);
+int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data);
 
 /**
  * iterate all refs in "patterns" by partitioning patterns into disjoint sets
@@ -354,8 +352,7 @@
  * callers should be prepared to ignore references that they did not ask for.
  */
 int for_each_fullref_in_prefixes(const char *namespace, const char **patterns,
-				 each_ref_fn fn, void *cb_data,
-				 unsigned int broken);
+				 each_ref_fn fn, void *cb_data);
 /**
  * iterate refs from the respective area.
  */
@@ -796,7 +793,7 @@
  * expiration policy that is desired.
  *
  * reflog_expiry_prepare_fn -- Called once after the reference is
- *     locked.
+ *     locked. Called with the OID of the locked reference.
  *
  * reflog_expiry_should_prune_fn -- Called once for each entry in the
  *     existing reflog. It should return true iff that entry should be
@@ -816,28 +813,25 @@
 typedef void reflog_expiry_cleanup_fn(void *cb_data);
 
 /*
- * Expire reflog entries for the specified reference. oid is the old
- * value of the reference. flags is a combination of the constants in
+ * Expire reflog entries for the specified reference.
+ * flags is a combination of the constants in
  * enum expire_reflog_flags. The three function pointers are described
  * above. On success, return zero.
  */
 int refs_reflog_expire(struct ref_store *refs,
 		       const char *refname,
-		       const struct object_id *oid,
 		       unsigned int flags,
 		       reflog_expiry_prepare_fn prepare_fn,
 		       reflog_expiry_should_prune_fn should_prune_fn,
 		       reflog_expiry_cleanup_fn cleanup_fn,
 		       void *policy_cb_data);
-int reflog_expire(const char *refname, const struct object_id *oid,
+int reflog_expire(const char *refname,
 		  unsigned int flags,
 		  reflog_expiry_prepare_fn prepare_fn,
 		  reflog_expiry_should_prune_fn should_prune_fn,
 		  reflog_expiry_cleanup_fn cleanup_fn,
 		  void *policy_cb_data);
 
-int ref_storage_backend_exists(const char *name);
-
 struct ref_store *get_main_ref_store(struct repository *r);
 
 /**
diff --git a/refs/debug.c b/refs/debug.c
index 1a7a9e1..8667c64 100644
--- a/refs/debug.c
+++ b/refs/debug.c
@@ -239,15 +239,14 @@
 
 static int debug_read_raw_ref(struct ref_store *ref_store, const char *refname,
 			      struct object_id *oid, struct strbuf *referent,
-			      unsigned int *type)
+			      unsigned int *type, int *failure_errno)
 {
 	struct debug_ref_store *drefs = (struct debug_ref_store *)ref_store;
 	int res = 0;
 
 	oidcpy(oid, null_oid());
-	errno = 0;
 	res = drefs->refs->be->read_raw_ref(drefs->refs, refname, oid, referent,
-					    type);
+					    type, failure_errno);
 
 	if (res == 0) {
 		trace_printf_key(&trace_refs, "read_raw_ref: %s: %s (=> %s) type %x: %d\n",
@@ -255,7 +254,7 @@
 	} else {
 		trace_printf_key(&trace_refs,
 				 "read_raw_ref: %s: %d (errno %d)\n", refname,
-				 res, errno);
+				 res, *failure_errno);
 	}
 	return res;
 }
@@ -365,8 +364,8 @@
 };
 
 static void debug_reflog_expiry_prepare(const char *refname,
-				    const struct object_id *oid,
-				    void *cb_data)
+					const struct object_id *oid,
+					void *cb_data)
 {
 	struct debug_reflog_expiry_should_prune *prune = cb_data;
 	trace_printf_key(&trace_refs, "reflog_expire_prepare: %s\n", refname);
@@ -392,7 +391,7 @@
 }
 
 static int debug_reflog_expire(struct ref_store *ref_store, const char *refname,
-			       const struct object_id *oid, unsigned int flags,
+			       unsigned int flags,
 			       reflog_expiry_prepare_fn prepare_fn,
 			       reflog_expiry_should_prune_fn should_prune_fn,
 			       reflog_expiry_cleanup_fn cleanup_fn,
@@ -405,7 +404,7 @@
 		.should_prune = should_prune_fn,
 		.cb_data = policy_cb_data,
 	};
-	int res = drefs->refs->be->reflog_expire(drefs->refs, refname, oid,
+	int res = drefs->refs->be->reflog_expire(drefs->refs, refname,
 						 flags, &debug_reflog_expiry_prepare,
 						 &debug_reflog_expiry_should_prune_fn,
 						 &debug_reflog_expiry_cleanup,
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 74c0385..151b005 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -79,13 +79,15 @@
  * Create a new submodule ref cache and add it to the internal
  * set of caches.
  */
-static struct ref_store *files_ref_store_create(const char *gitdir,
+static struct ref_store *files_ref_store_create(struct repository *repo,
+						const char *gitdir,
 						unsigned int flags)
 {
 	struct files_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
 	struct strbuf sb = STRBUF_INIT;
 
+	ref_store->repo = repo;
 	ref_store->gitdir = xstrdup(gitdir);
 	base_ref_store_init(ref_store, &refs_be_files);
 	refs->store_flags = flags;
@@ -93,7 +95,7 @@
 	get_common_dir_noenv(&sb, gitdir);
 	refs->gitcommondir = strbuf_detach(&sb, NULL);
 	strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
-	refs->packed_ref_store = packed_ref_store_create(sb.buf, flags);
+	refs->packed_ref_store = packed_ref_store_create(repo, sb.buf, flags);
 	strbuf_release(&sb);
 
 	chdir_notify_reparent("files-backend $GIT_DIR", &refs->base.gitdir);
@@ -227,7 +229,7 @@
 		pos = search_ref_dir(dir, prefix, prefix_len);
 		if (pos >= 0)
 			continue;
-		child_entry = create_dir_entry(dir->cache, prefix, prefix_len, 1);
+		child_entry = create_dir_entry(dir->cache, prefix, prefix_len);
 		add_entry_to_dir(dir, child_entry);
 	}
 }
@@ -278,7 +280,7 @@
 			strbuf_addch(&refname, '/');
 			add_entry_to_dir(dir,
 					 create_dir_entry(dir->cache, refname.buf,
-							  refname.len, 1));
+							  refname.len));
 		} else {
 			if (!refs_resolve_ref_unsafe(&refs->base,
 						     refname.buf,
@@ -336,14 +338,14 @@
 		 * lazily):
 		 */
 		add_entry_to_dir(get_ref_dir(refs->loose->root),
-				 create_dir_entry(refs->loose, "refs/", 5, 1));
+				 create_dir_entry(refs->loose, "refs/", 5));
 	}
 	return refs->loose;
 }
 
-static int files_read_raw_ref(struct ref_store *ref_store,
-			      const char *refname, struct object_id *oid,
-			      struct strbuf *referent, unsigned int *type)
+static int files_read_raw_ref(struct ref_store *ref_store, const char *refname,
+			      struct object_id *oid, struct strbuf *referent,
+			      unsigned int *type, int *failure_errno)
 {
 	struct files_ref_store *refs =
 		files_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
@@ -354,7 +356,6 @@
 	struct stat st;
 	int fd;
 	int ret = -1;
-	int save_errno;
 	int remaining_retries = 3;
 
 	*type = 0;
@@ -459,10 +460,9 @@
 	ret = parse_loose_ref_contents(buf, oid, referent, type);
 
 out:
-	save_errno = errno;
+	*failure_errno = errno;
 	strbuf_release(&sb_path);
 	strbuf_release(&sb_contents);
-	errno = save_errno;
 	return ret;
 }
 
@@ -531,7 +531,6 @@
 static int lock_raw_ref(struct files_ref_store *refs,
 			const char *refname, int mustexist,
 			const struct string_list *extras,
-			const struct string_list *skip,
 			struct ref_lock **lock_p,
 			struct strbuf *referent,
 			unsigned int *type,
@@ -541,6 +540,7 @@
 	struct strbuf ref_file = STRBUF_INIT;
 	int attempts_remaining = 3;
 	int ret = TRANSACTION_GENERIC_ERROR;
+	int failure_errno;
 
 	assert(err);
 	files_assert_main_repository(refs, "lock_raw_ref");
@@ -568,7 +568,7 @@
 		 * reason to expect this error to be transitory.
 		 */
 		if (refs_verify_refname_available(&refs->base, refname,
-						  extras, skip, err)) {
+						  extras, NULL, err)) {
 			if (mustexist) {
 				/*
 				 * To the user the relevant error is
@@ -611,7 +611,9 @@
 	if (hold_lock_file_for_update_timeout(
 			    &lock->lk, ref_file.buf, LOCK_NO_DEREF,
 			    get_files_ref_lock_timeout_ms()) < 0) {
-		if (errno == ENOENT && --attempts_remaining > 0) {
+		int myerr = errno;
+		errno = 0;
+		if (myerr == ENOENT && --attempts_remaining > 0) {
 			/*
 			 * Maybe somebody just deleted one of the
 			 * directories leading to ref_file.  Try
@@ -619,7 +621,7 @@
 			 */
 			goto retry;
 		} else {
-			unable_to_lock_message(ref_file.buf, errno, err);
+			unable_to_lock_message(ref_file.buf, myerr, err);
 			goto error_return;
 		}
 	}
@@ -629,9 +631,9 @@
 	 * fear that its value will change.
 	 */
 
-	if (files_read_raw_ref(&refs->base, refname,
-			       &lock->old_oid, referent, type)) {
-		if (errno == ENOENT) {
+	if (files_read_raw_ref(&refs->base, refname, &lock->old_oid, referent,
+			       type, &failure_errno)) {
+		if (failure_errno == ENOENT) {
 			if (mustexist) {
 				/* Garden variety missing reference. */
 				strbuf_addf(err, "unable to resolve reference '%s'",
@@ -655,7 +657,7 @@
 				 *   reference named "refs/foo/bar/baz".
 				 */
 			}
-		} else if (errno == EISDIR) {
+		} else if (failure_errno == EISDIR) {
 			/*
 			 * There is a directory in the way. It might have
 			 * contained references that have been deleted. If
@@ -673,7 +675,7 @@
 							  REMOVE_DIR_EMPTY_ONLY)) {
 				if (refs_verify_refname_available(
 						    &refs->base, refname,
-						    extras, skip, err)) {
+						    extras, NULL, err)) {
 					/*
 					 * The error message set by
 					 * verify_refname_available() is OK.
@@ -693,13 +695,13 @@
 					goto error_return;
 				}
 			}
-		} else if (errno == EINVAL && (*type & REF_ISBROKEN)) {
+		} else if (failure_errno == EINVAL && (*type & REF_ISBROKEN)) {
 			strbuf_addf(err, "unable to resolve reference '%s': "
 				    "reference broken", refname);
 			goto error_return;
 		} else {
 			strbuf_addf(err, "unable to resolve reference '%s': %s",
-				    refname, strerror(errno));
+				    refname, strerror(failure_errno));
 			goto error_return;
 		}
 
@@ -710,7 +712,7 @@
 		 */
 		if (refs_verify_refname_available(
 				    refs->packed_ref_store, refname,
-				    extras, skip, err))
+				    extras, NULL, err))
 			goto error_return;
 	}
 
@@ -730,6 +732,7 @@
 	struct ref_iterator base;
 
 	struct ref_iterator *iter0;
+	struct repository *repo;
 	unsigned int flags;
 };
 
@@ -744,8 +747,14 @@
 		    ref_type(iter->iter0->refname) != REF_TYPE_PER_WORKTREE)
 			continue;
 
+		if ((iter->flags & DO_FOR_EACH_OMIT_DANGLING_SYMREFS) &&
+		    (iter->iter0->flags & REF_ISSYMREF) &&
+		    (iter->iter0->flags & REF_ISBROKEN))
+			continue;
+
 		if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
 		    !ref_resolves_to_object(iter->iter0->refname,
+					    iter->repo,
 					    iter->iter0->oid,
 					    iter->iter0->flags))
 			continue;
@@ -824,7 +833,7 @@
 	 */
 
 	loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
-					      prefix, 1);
+					      prefix, ref_store->repo, 1);
 
 	/*
 	 * The packed-refs file might contain broken references, for
@@ -848,45 +857,119 @@
 	base_ref_iterator_init(ref_iterator, &files_ref_iterator_vtable,
 			       overlay_iter->ordered);
 	iter->iter0 = overlay_iter;
+	iter->repo = ref_store->repo;
 	iter->flags = flags;
 
 	return ref_iterator;
 }
 
 /*
- * Verify that the reference locked by lock has the value old_oid
- * (unless it is NULL).  Fail if the reference doesn't exist and
- * mustexist is set. Return 0 on success. On error, write an error
- * message to err, set errno, and return a negative value.
+ * Callback function for raceproof_create_file(). This function is
+ * expected to do something that makes dirname(path) permanent despite
+ * the fact that other processes might be cleaning up empty
+ * directories at the same time. Usually it will create a file named
+ * path, but alternatively it could create another file in that
+ * directory, or even chdir() into that directory. The function should
+ * return 0 if the action was completed successfully. On error, it
+ * should return a nonzero result and set errno.
+ * raceproof_create_file() treats two errno values specially:
+ *
+ * - ENOENT -- dirname(path) does not exist. In this case,
+ *             raceproof_create_file() tries creating dirname(path)
+ *             (and any parent directories, if necessary) and calls
+ *             the function again.
+ *
+ * - EISDIR -- the file already exists and is a directory. In this
+ *             case, raceproof_create_file() removes the directory if
+ *             it is empty (and recursively any empty directories that
+ *             it contains) and calls the function again.
+ *
+ * Any other errno causes raceproof_create_file() to fail with the
+ * callback's return value and errno.
+ *
+ * Obviously, this function should be OK with being called again if it
+ * fails with ENOENT or EISDIR. In other scenarios it will not be
+ * called again.
  */
-static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
-		       const struct object_id *old_oid, int mustexist,
-		       struct strbuf *err)
-{
-	assert(err);
+typedef int create_file_fn(const char *path, void *cb);
 
-	if (refs_read_ref_full(ref_store, lock->ref_name,
-			       mustexist ? RESOLVE_REF_READING : 0,
-			       &lock->old_oid, NULL)) {
-		if (old_oid) {
-			int save_errno = errno;
-			strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
-			errno = save_errno;
-			return -1;
-		} else {
-			oidclr(&lock->old_oid);
-			return 0;
-		}
+/*
+ * Create a file in dirname(path) by calling fn, creating leading
+ * directories if necessary. Retry a few times in case we are racing
+ * with another process that is trying to clean up the directory that
+ * contains path. See the documentation for create_file_fn for more
+ * details.
+ *
+ * Return the value and set the errno that resulted from the most
+ * recent call of fn. fn is always called at least once, and will be
+ * called more than once if it returns ENOENT or EISDIR.
+ */
+static int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
+{
+	/*
+	 * The number of times we will try to remove empty directories
+	 * in the way of path. This is only 1 because if another
+	 * process is racily creating directories that conflict with
+	 * us, we don't want to fight against them.
+	 */
+	int remove_directories_remaining = 1;
+
+	/*
+	 * The number of times that we will try to create the
+	 * directories containing path. We are willing to attempt this
+	 * more than once, because another process could be trying to
+	 * clean up empty directories at the same time as we are
+	 * trying to create them.
+	 */
+	int create_directories_remaining = 3;
+
+	/* A scratch copy of path, filled lazily if we need it: */
+	struct strbuf path_copy = STRBUF_INIT;
+
+	int ret, save_errno;
+
+	/* Sanity check: */
+	assert(*path);
+
+retry_fn:
+	ret = fn(path, cb);
+	save_errno = errno;
+	if (!ret)
+		goto out;
+
+	if (errno == EISDIR && remove_directories_remaining-- > 0) {
+		/*
+		 * A directory is in the way. Maybe it is empty; try
+		 * to remove it:
+		 */
+		if (!path_copy.len)
+			strbuf_addstr(&path_copy, path);
+
+		if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
+			goto retry_fn;
+	} else if (errno == ENOENT && create_directories_remaining-- > 0) {
+		/*
+		 * Maybe the containing directory didn't exist, or
+		 * maybe it was just deleted by a process that is
+		 * racing with us to clean up empty directories. Try
+		 * to create it:
+		 */
+		enum scld_error scld_result;
+
+		if (!path_copy.len)
+			strbuf_addstr(&path_copy, path);
+
+		do {
+			scld_result = safe_create_leading_directories(path_copy.buf);
+			if (scld_result == SCLD_OK)
+				goto retry_fn;
+		} while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
 	}
-	if (old_oid && !oideq(&lock->old_oid, old_oid)) {
-		strbuf_addf(err, "ref '%s' is at %s but expected %s",
-			    lock->ref_name,
-			    oid_to_hex(&lock->old_oid),
-			    oid_to_hex(old_oid));
-		errno = EBUSY;
-		return -1;
-	}
-	return 0;
+
+out:
+	strbuf_release(&path_copy);
+	errno = save_errno;
+	return ret;
 }
 
 static int remove_empty_directories(struct strbuf *path)
@@ -910,64 +993,27 @@
 
 /*
  * Locks a ref returning the lock on success and NULL on failure.
- * On failure errno is set to something meaningful.
  */
 static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
-					   const char *refname,
-					   const struct object_id *old_oid,
-					   const struct string_list *extras,
-					   const struct string_list *skip,
-					   unsigned int flags, int *type,
+					   const char *refname, int *type,
 					   struct strbuf *err)
 {
 	struct strbuf ref_file = STRBUF_INIT;
 	struct ref_lock *lock;
-	int last_errno = 0;
-	int mustexist = (old_oid && !is_null_oid(old_oid));
-	int resolve_flags = RESOLVE_REF_NO_RECURSE;
-	int resolved;
 
 	files_assert_main_repository(refs, "lock_ref_oid_basic");
 	assert(err);
 
 	CALLOC_ARRAY(lock, 1);
 
-	if (mustexist)
-		resolve_flags |= RESOLVE_REF_READING;
-	if (flags & REF_DELETING)
-		resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
-
 	files_ref_path(refs, &ref_file, refname);
-	resolved = !!refs_resolve_ref_unsafe(&refs->base,
-					     refname, resolve_flags,
-					     &lock->old_oid, type);
-	if (!resolved && errno == EISDIR) {
-		/*
-		 * we are trying to lock foo but we used to
-		 * have foo/bar which now does not exist;
-		 * it is normal for the empty directory 'foo'
-		 * to remain.
-		 */
-		if (remove_empty_directories(&ref_file)) {
-			last_errno = errno;
-			if (!refs_verify_refname_available(
-					    &refs->base,
-					    refname, extras, skip, err))
-				strbuf_addf(err, "there are still refs under '%s'",
-					    refname);
-			goto error_return;
-		}
-		resolved = !!refs_resolve_ref_unsafe(&refs->base,
-						     refname, resolve_flags,
-						     &lock->old_oid, type);
-	}
-	if (!resolved) {
-		last_errno = errno;
-		if (last_errno != ENOTDIR ||
-		    !refs_verify_refname_available(&refs->base, refname,
-						   extras, skip, err))
+	if (!refs_resolve_ref_unsafe(&refs->base, refname,
+				     RESOLVE_REF_NO_RECURSE,
+				     &lock->old_oid, type)) {
+		if (!refs_verify_refname_available(&refs->base, refname,
+						   NULL, NULL, err))
 			strbuf_addf(err, "unable to resolve reference '%s': %s",
-				    refname, strerror(last_errno));
+				    refname, strerror(errno));
 
 		goto error_return;
 	}
@@ -980,23 +1026,20 @@
 	 */
 	if (is_null_oid(&lock->old_oid) &&
 	    refs_verify_refname_available(refs->packed_ref_store, refname,
-					  extras, skip, err)) {
-		last_errno = ENOTDIR;
+					  NULL, NULL, err))
 		goto error_return;
-	}
 
 	lock->ref_name = xstrdup(refname);
 
 	if (raceproof_create_file(ref_file.buf, create_reflock, &lock->lk)) {
-		last_errno = errno;
 		unable_to_lock_message(ref_file.buf, errno, err);
 		goto error_return;
 	}
 
-	if (verify_lock(&refs->base, lock, old_oid, mustexist, err)) {
-		last_errno = errno;
-		goto error_return;
-	}
+	if (refs_read_ref_full(&refs->base, lock->ref_name,
+			       0,
+			       &lock->old_oid, NULL))
+		oidclr(&lock->old_oid);
 	goto out;
 
  error_return:
@@ -1005,7 +1048,6 @@
 
  out:
 	strbuf_release(&ref_file);
-	errno = last_errno;
 	return lock;
 }
 
@@ -1132,7 +1174,7 @@
 		return 0;
 
 	/* Do not pack broken refs: */
-	if (!ref_resolves_to_object(refname, oid, ref_flags))
+	if (!ref_resolves_to_object(refname, the_repository, oid, ref_flags))
 		return 0;
 
 	return 1;
@@ -1155,7 +1197,8 @@
 
 	packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
 
-	iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
+	iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL,
+					the_repository, 0);
 	while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
 		/*
 		 * If the loose reference can be packed, add an entry
@@ -1415,8 +1458,7 @@
 
 	logmoved = log;
 
-	lock = lock_ref_oid_basic(refs, newrefname, NULL, NULL, NULL,
-				  REF_NO_DEREF, NULL, &err);
+	lock = lock_ref_oid_basic(refs, newrefname, NULL, &err);
 	if (!lock) {
 		if (copy)
 			error("unable to copy '%s' to '%s': %s", oldrefname, newrefname, err.buf);
@@ -1438,8 +1480,7 @@
 	goto out;
 
  rollback:
-	lock = lock_ref_oid_basic(refs, oldrefname, NULL, NULL, NULL,
-				  REF_NO_DEREF, NULL, &err);
+	lock = lock_ref_oid_basic(refs, oldrefname, NULL, &err);
 	if (!lock) {
 		error("unable to lock %s for rollback: %s", oldrefname, err.buf);
 		strbuf_release(&err);
@@ -1846,9 +1887,7 @@
 	struct ref_lock *lock;
 	int ret;
 
-	lock = lock_ref_oid_basic(refs, refname, NULL,
-				  NULL, NULL, REF_NO_DEREF, NULL,
-				  &err);
+	lock = lock_ref_oid_basic(refs, refname, NULL, &err);
 	if (!lock) {
 		error("%s", err.buf);
 		strbuf_release(&err);
@@ -2416,7 +2455,7 @@
 	}
 
 	ret = lock_raw_ref(refs, update->refname, mustexist,
-			   affected_refnames, NULL,
+			   affected_refnames,
 			   &lock, &referent,
 			   &update->type, err);
 	if (ret) {
@@ -3037,7 +3076,7 @@
 }
 
 static int files_reflog_expire(struct ref_store *ref_store,
-			       const char *refname, const struct object_id *oid,
+			       const char *refname,
 			       unsigned int flags,
 			       reflog_expiry_prepare_fn prepare_fn,
 			       reflog_expiry_should_prune_fn should_prune_fn,
@@ -3054,6 +3093,7 @@
 	int status = 0;
 	int type;
 	struct strbuf err = STRBUF_INIT;
+	const struct object_id *oid;
 
 	memset(&cb, 0, sizeof(cb));
 	cb.flags = flags;
@@ -3065,14 +3105,26 @@
 	 * reference itself, plus we might need to update the
 	 * reference if --updateref was specified:
 	 */
-	lock = lock_ref_oid_basic(refs, refname, oid,
-				  NULL, NULL, REF_NO_DEREF,
-				  &type, &err);
+	lock = lock_ref_oid_basic(refs, refname, &type, &err);
 	if (!lock) {
 		error("cannot lock ref '%s': %s", refname, err.buf);
 		strbuf_release(&err);
 		return -1;
 	}
+	oid = &lock->old_oid;
+
+	/*
+	 * When refs are deleted, their reflog is deleted before the
+	 * ref itself is deleted. This is because there is no separate
+	 * lock for reflog; instead we take a lock on the ref with
+	 * lock_ref_oid_basic().
+	 *
+	 * If a race happens and the reflog doesn't exist after we've
+	 * acquired the lock that's OK. We've got nothing more to do;
+	 * We were asked to delete the reflog, but someone else
+	 * deleted it! The caller doesn't care that we deleted it,
+	 * just that it is deleted. So we can return successfully.
+	 */
 	if (!refs_reflog_exists(ref_store, refname)) {
 		unlock_ref(lock);
 		return 0;
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index f8aa97d..1c5211b 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -193,13 +193,15 @@
 	}
 }
 
-struct ref_store *packed_ref_store_create(const char *path,
+struct ref_store *packed_ref_store_create(struct repository *repo,
+					  const char *path,
 					  unsigned int store_flags)
 {
 	struct packed_ref_store *refs = xcalloc(1, sizeof(*refs));
 	struct ref_store *ref_store = (struct ref_store *)refs;
 
 	base_ref_store_init(ref_store, &refs_be_packed);
+	ref_store->repo = repo;
 	ref_store->gitdir = xstrdup(path);
 	refs->store_flags = store_flags;
 
@@ -724,9 +726,9 @@
 	return refs->snapshot;
 }
 
-static int packed_read_raw_ref(struct ref_store *ref_store,
-			       const char *refname, struct object_id *oid,
-			       struct strbuf *referent, unsigned int *type)
+static int packed_read_raw_ref(struct ref_store *ref_store, const char *refname,
+			       struct object_id *oid, struct strbuf *referent,
+			       unsigned int *type, int *failure_errno)
 {
 	struct packed_ref_store *refs =
 		packed_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
@@ -739,7 +741,7 @@
 
 	if (!rec) {
 		/* refname is not a packed reference. */
-		errno = ENOENT;
+		*failure_errno = ENOENT;
 		return -1;
 	}
 
@@ -776,6 +778,7 @@
 	struct object_id oid, peeled;
 	struct strbuf refname_buf;
 
+	struct repository *repo;
 	unsigned int flags;
 };
 
@@ -864,8 +867,8 @@
 			continue;
 
 		if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
-		    !ref_resolves_to_object(iter->base.refname, &iter->oid,
-					    iter->flags))
+		    !ref_resolves_to_object(iter->base.refname, iter->repo,
+					    &iter->oid, iter->flags))
 			continue;
 
 		return ITER_OK;
@@ -883,6 +886,9 @@
 	struct packed_ref_iterator *iter =
 		(struct packed_ref_iterator *)ref_iterator;
 
+	if (iter->repo != the_repository)
+		BUG("peeling for non-the_repository is not supported");
+
 	if ((iter->base.flags & REF_KNOWS_PEELED)) {
 		oidcpy(peeled, &iter->peeled);
 		return is_null_oid(&iter->peeled) ? -1 : 0;
@@ -954,6 +960,7 @@
 
 	iter->base.oid = &iter->oid;
 
+	iter->repo = ref_store->repo;
 	iter->flags = flags;
 
 	if (prefix && *prefix)
@@ -1600,6 +1607,7 @@
 				      const char *refname,
 				      each_reflog_ent_fn fn, void *cb_data)
 {
+	BUG("packed reference store does not support reflogs");
 	return 0;
 }
 
@@ -1608,12 +1616,14 @@
 					      each_reflog_ent_fn fn,
 					      void *cb_data)
 {
+	BUG("packed reference store does not support reflogs");
 	return 0;
 }
 
 static int packed_reflog_exists(struct ref_store *ref_store,
 			       const char *refname)
 {
+	BUG("packed reference store does not support reflogs");
 	return 0;
 }
 
@@ -1627,17 +1637,19 @@
 static int packed_delete_reflog(struct ref_store *ref_store,
 			       const char *refname)
 {
+	BUG("packed reference store does not support reflogs");
 	return 0;
 }
 
 static int packed_reflog_expire(struct ref_store *ref_store,
-				const char *refname, const struct object_id *oid,
+				const char *refname,
 				unsigned int flags,
 				reflog_expiry_prepare_fn prepare_fn,
 				reflog_expiry_should_prune_fn should_prune_fn,
 				reflog_expiry_cleanup_fn cleanup_fn,
 				void *policy_cb_data)
 {
+	BUG("packed reference store does not support reflogs");
 	return 0;
 }
 
diff --git a/refs/packed-backend.h b/refs/packed-backend.h
index a01a0af..f61a73e 100644
--- a/refs/packed-backend.h
+++ b/refs/packed-backend.h
@@ -1,6 +1,7 @@
 #ifndef REFS_PACKED_BACKEND_H
 #define REFS_PACKED_BACKEND_H
 
+struct repository;
 struct ref_transaction;
 
 /*
@@ -12,7 +13,8 @@
  * even among packed refs.
  */
 
-struct ref_store *packed_ref_store_create(const char *path,
+struct ref_store *packed_ref_store_create(struct repository *repo,
+					  const char *path,
 					  unsigned int store_flags);
 
 /*
diff --git a/refs/ref-cache.c b/refs/ref-cache.c
index 49d732f..be4aa5e 100644
--- a/refs/ref-cache.c
+++ b/refs/ref-cache.c
@@ -49,7 +49,7 @@
 
 	ret->ref_store = refs;
 	ret->fill_ref_dir = fill_ref_dir;
-	ret->root = create_dir_entry(ret, "", 0, 1);
+	ret->root = create_dir_entry(ret, "", 0);
 	return ret;
 }
 
@@ -86,14 +86,13 @@
 }
 
 struct ref_entry *create_dir_entry(struct ref_cache *cache,
-				   const char *dirname, size_t len,
-				   int incomplete)
+				   const char *dirname, size_t len)
 {
 	struct ref_entry *direntry;
 
 	FLEX_ALLOC_MEM(direntry, name, dirname, len);
 	direntry->u.subdir.cache = cache;
-	direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
+	direntry->flag = REF_DIR | REF_INCOMPLETE;
 	return direntry;
 }
 
@@ -144,30 +143,19 @@
 /*
  * Search for a directory entry directly within dir (without
  * recursing).  Sort dir if necessary.  subdirname must be a directory
- * name (i.e., end in '/').  If mkdir is set, then create the
- * directory if it is missing; otherwise, return NULL if the desired
+ * name (i.e., end in '/'). Returns NULL if the desired
  * directory cannot be found.  dir must already be complete.
  */
 static struct ref_dir *search_for_subdir(struct ref_dir *dir,
-					 const char *subdirname, size_t len,
-					 int mkdir)
+					 const char *subdirname, size_t len)
 {
 	int entry_index = search_ref_dir(dir, subdirname, len);
 	struct ref_entry *entry;
-	if (entry_index == -1) {
-		if (!mkdir)
-			return NULL;
-		/*
-		 * Since dir is complete, the absence of a subdir
-		 * means that the subdir really doesn't exist;
-		 * therefore, create an empty record for it but mark
-		 * the record complete.
-		 */
-		entry = create_dir_entry(dir->cache, subdirname, len, 0);
-		add_entry_to_dir(dir, entry);
-	} else {
-		entry = dir->entries[entry_index];
-	}
+
+	if (entry_index == -1)
+		return NULL;
+
+	entry = dir->entries[entry_index];
 	return get_ref_dir(entry);
 }
 
@@ -176,18 +164,17 @@
  * tree that should hold refname. If refname is a directory name
  * (i.e., it ends in '/'), then return that ref_dir itself. dir must
  * represent the top-level directory and must already be complete.
- * Sort ref_dirs and recurse into subdirectories as necessary. If
- * mkdir is set, then create any missing directories; otherwise,
+ * Sort ref_dirs and recurse into subdirectories as necessary. Will
  * return NULL if the desired directory cannot be found.
  */
 static struct ref_dir *find_containing_dir(struct ref_dir *dir,
-					   const char *refname, int mkdir)
+					   const char *refname)
 {
 	const char *slash;
 	for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
 		size_t dirnamelen = slash - refname + 1;
 		struct ref_dir *subdir;
-		subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
+		subdir = search_for_subdir(dir, refname, dirnamelen);
 		if (!subdir) {
 			dir = NULL;
 			break;
@@ -202,7 +189,7 @@
 {
 	int entry_index;
 	struct ref_entry *entry;
-	dir = find_containing_dir(dir, refname, 0);
+	dir = find_containing_dir(dir, refname);
 	if (!dir)
 		return NULL;
 	entry_index = search_ref_dir(dir, refname, strlen(refname));
@@ -212,50 +199,6 @@
 	return (entry->flag & REF_DIR) ? NULL : entry;
 }
 
-int remove_entry_from_dir(struct ref_dir *dir, const char *refname)
-{
-	int refname_len = strlen(refname);
-	int entry_index;
-	struct ref_entry *entry;
-	int is_dir = refname[refname_len - 1] == '/';
-	if (is_dir) {
-		/*
-		 * refname represents a reference directory.  Remove
-		 * the trailing slash; otherwise we will get the
-		 * directory *representing* refname rather than the
-		 * one *containing* it.
-		 */
-		char *dirname = xmemdupz(refname, refname_len - 1);
-		dir = find_containing_dir(dir, dirname, 0);
-		free(dirname);
-	} else {
-		dir = find_containing_dir(dir, refname, 0);
-	}
-	if (!dir)
-		return -1;
-	entry_index = search_ref_dir(dir, refname, refname_len);
-	if (entry_index == -1)
-		return -1;
-	entry = dir->entries[entry_index];
-
-	MOVE_ARRAY(&dir->entries[entry_index],
-		   &dir->entries[entry_index + 1], dir->nr - entry_index - 1);
-	dir->nr--;
-	if (dir->sorted > entry_index)
-		dir->sorted--;
-	free_ref_entry(entry);
-	return dir->nr;
-}
-
-int add_ref_entry(struct ref_dir *dir, struct ref_entry *ref)
-{
-	dir = find_containing_dir(dir, ref->name, 1);
-	if (!dir)
-		return -1;
-	add_entry_to_dir(dir, ref);
-	return 0;
-}
-
 /*
  * Emit a warning and return true iff ref1 and ref2 have the same name
  * and the same oid. Die if they have the same name but different
@@ -435,6 +378,8 @@
 	 * on from there.)
 	 */
 	struct cache_ref_iterator_level *levels;
+
+	struct repository *repo;
 };
 
 static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
@@ -491,6 +436,11 @@
 static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
 				   struct object_id *peeled)
 {
+	struct cache_ref_iterator *iter =
+		(struct cache_ref_iterator *)ref_iterator;
+
+	if (iter->repo != the_repository)
+		BUG("peeling for non-the_repository is not supported");
 	return peel_object(ref_iterator->oid, peeled) ? -1 : 0;
 }
 
@@ -513,6 +463,7 @@
 
 struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache,
 					      const char *prefix,
+					      struct repository *repo,
 					      int prime_dir)
 {
 	struct ref_dir *dir;
@@ -522,7 +473,7 @@
 
 	dir = get_ref_dir(cache->root);
 	if (prefix && *prefix)
-		dir = find_containing_dir(dir, prefix, 0);
+		dir = find_containing_dir(dir, prefix);
 	if (!dir)
 		/* There's nothing to iterate over. */
 		return empty_ref_iterator_begin();
@@ -547,5 +498,7 @@
 		level->prefix_state = PREFIX_CONTAINS_DIR;
 	}
 
+	iter->repo = repo;
+
 	return ref_iterator;
 }
diff --git a/refs/ref-cache.h b/refs/ref-cache.h
index 3bfb89d..850d9d3 100644
--- a/refs/ref-cache.h
+++ b/refs/ref-cache.h
@@ -169,8 +169,7 @@
  * "refs/heads/") or "" for the top-level directory.
  */
 struct ref_entry *create_dir_entry(struct ref_cache *cache,
-				   const char *dirname, size_t len,
-				   int incomplete);
+				   const char *dirname, size_t len);
 
 struct ref_entry *create_ref_entry(const char *refname,
 				   const struct object_id *oid, int flag);
@@ -200,29 +199,6 @@
 void add_entry_to_dir(struct ref_dir *dir, struct ref_entry *entry);
 
 /*
- * Remove the entry with the given name from dir, recursing into
- * subdirectories as necessary.  If refname is the name of a directory
- * (i.e., ends with '/'), then remove the directory and its contents.
- * If the removal was successful, return the number of entries
- * remaining in the directory entry that contained the deleted entry.
- * If the name was not found, return -1.  Please note that this
- * function only deletes the entry from the cache; it does not delete
- * it from the filesystem or ensure that other cache entries (which
- * might be symbolic references to the removed entry) are updated.
- * Nor does it remove any containing dir entries that might be made
- * empty by the removal.  dir must represent the top-level directory
- * and must already be complete.
- */
-int remove_entry_from_dir(struct ref_dir *dir, const char *refname);
-
-/*
- * Add a ref_entry to the ref_dir (unsorted), recursing into
- * subdirectories as necessary.  dir must represent the top-level
- * directory.  Return 0 on success.
- */
-int add_ref_entry(struct ref_dir *dir, struct ref_entry *ref);
-
-/*
  * Find the value entry with the given name in dir, sorting ref_dirs
  * and recursing into subdirectories as necessary.  If the name is not
  * found or it corresponds to a directory entry, return NULL.
@@ -238,6 +214,7 @@
  */
 struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache,
 					      const char *prefix,
+					      struct repository *repo,
 					      int prime_dir);
 
 #endif /* REFS_REF_CACHE_H */
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 3155708..1222474 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -66,6 +66,7 @@
  * referred-to object does not exist, emit a warning and return false.
  */
 int ref_resolves_to_object(const char *refname,
+			   struct repository *repo,
 			   const struct object_id *oid,
 			   unsigned int flags);
 
@@ -245,8 +246,36 @@
 /* We allow "recursive" symbolic refs. Only within reason, though */
 #define SYMREF_MAXDEPTH 5
 
-/* Include broken references in a do_for_each_ref*() iteration: */
-#define DO_FOR_EACH_INCLUDE_BROKEN 0x01
+/*
+ * These flags are passed to refs_ref_iterator_begin() (and do_for_each_ref(),
+ * which feeds it).
+ */
+enum do_for_each_ref_flags {
+	/*
+	 * Include broken references in a do_for_each_ref*() iteration, which
+	 * would normally be omitted. This includes both refs that point to
+	 * missing objects (a true repository corruption), ones with illegal
+	 * names (which we prefer not to expose to callers), as well as
+	 * dangling symbolic refs (i.e., those that point to a non-existent
+	 * ref; this is not a corruption, but as they have no valid oid, we
+	 * omit them from normal iteration results).
+	 */
+	DO_FOR_EACH_INCLUDE_BROKEN = (1 << 0),
+
+	/*
+	 * Only include per-worktree refs in a do_for_each_ref*() iteration.
+	 * Normally this will be used with a files ref_store, since that's
+	 * where all reference backends will presumably store their
+	 * per-worktree refs.
+	 */
+	DO_FOR_EACH_PER_WORKTREE_ONLY = (1 << 1),
+
+	/*
+	 * Omit dangling symrefs from output; this only has an effect with
+	 * INCLUDE_BROKEN, since they are otherwise not included at all.
+	 */
+	DO_FOR_EACH_OMIT_DANGLING_SYMREFS = (1 << 2),
+};
 
 /*
  * Reference iterators
@@ -349,16 +378,12 @@
  * Return an iterator that goes over each reference in `refs` for
  * which the refname begins with prefix. If trim is non-zero, then
  * trim that many characters off the beginning of each refname.
- * The output is ordered by refname. The following flags are supported:
- *
- * DO_FOR_EACH_INCLUDE_BROKEN: include broken references in
- *         the iteration.
- *
- * DO_FOR_EACH_PER_WORKTREE_ONLY: only produce REF_TYPE_PER_WORKTREE refs.
+ * The output is ordered by refname.
  */
 struct ref_iterator *refs_ref_iterator_begin(
 		struct ref_store *refs,
-		const char *prefix, int trim, int flags);
+		const char *prefix, int trim,
+		enum do_for_each_ref_flags flags);
 
 /*
  * A callback function used to instruct merge_ref_iterator how to
@@ -446,10 +471,8 @@
 /*
  * backend-specific implementation of ref_iterator_advance. For symrefs, the
  * function should set REF_ISSYMREF, and it should also dereference the symref
- * to provide the OID referent. If DO_FOR_EACH_INCLUDE_BROKEN is set, symrefs
- * with non-existent referents and refs pointing to non-existent object names
- * should also be returned. If DO_FOR_EACH_PER_WORKTREE_ONLY, only
- * REF_TYPE_PER_WORKTREE refs should be returned.
+ * to provide the OID referent. It should respect do_for_each_ref_flags
+ * that were passed to refs_ref_iterator_begin().
  */
 typedef int ref_iterator_advance_fn(struct ref_iterator *ref_iterator);
 
@@ -498,14 +521,6 @@
 				  struct ref_iterator *iter,
 				  each_repo_ref_fn fn, void *cb_data);
 
-/*
- * Only include per-worktree refs in a do_for_each_ref*() iteration.
- * Normally this will be used with a files ref_store, since that's
- * where all reference backends will presumably store their
- * per-worktree refs.
- */
-#define DO_FOR_EACH_PER_WORKTREE_ONLY 0x02
-
 struct ref_store;
 
 /* refs backends */
@@ -525,7 +540,8 @@
  * should call base_ref_store_init() to initialize the shared part of
  * the ref_store and to record the ref_store for later lookup.
  */
-typedef struct ref_store *ref_store_init_fn(const char *gitdir,
+typedef struct ref_store *ref_store_init_fn(struct repository *repo,
+					    const char *gitdir,
 					    unsigned int flags);
 
 typedef int ref_init_db_fn(struct ref_store *refs, struct strbuf *err);
@@ -593,7 +609,7 @@
 			     int force_create, struct strbuf *err);
 typedef int delete_reflog_fn(struct ref_store *ref_store, const char *refname);
 typedef int reflog_expire_fn(struct ref_store *ref_store,
-			     const char *refname, const struct object_id *oid,
+			     const char *refname,
 			     unsigned int flags,
 			     reflog_expiry_prepare_fn prepare_fn,
 			     reflog_expiry_should_prune_fn should_prune_fn,
@@ -620,11 +636,15 @@
  * properly-formatted or even safe reference name. NEITHER INPUT NOR
  * OUTPUT REFERENCE NAMES ARE VALIDATED WITHIN THIS FUNCTION.
  *
- * Return 0 on success. If the ref doesn't exist, set errno to ENOENT
- * and return -1. If the ref exists but is neither a symbolic ref nor
- * an object ID, it is broken; set REF_ISBROKEN in type, set errno to
- * EINVAL, and return -1. If there is another error reading the ref,
- * set errno appropriately and return -1.
+ * Return 0 on success, or -1 on failure. If the ref exists but is neither a
+ * symbolic ref nor an object ID, it is broken. In this case set REF_ISBROKEN in
+ * type, and return -1 (failure_errno should not be ENOENT)
+ *
+ * failure_errno provides errno codes that are interpreted beyond error
+ * reporting. The following error codes have special meaning:
+ *    * ENOENT: the ref doesn't exist
+ *    * EISDIR: ref name is a directory
+ *    * ENOTDIR: ref prefix is not a directory
  *
  * Backend-specific flags might be set in type as well, regardless of
  * outcome.
@@ -638,9 +658,9 @@
  * - in all other cases, referent will be untouched, and therefore
  *   refname will still be valid and unchanged.
  */
-typedef int read_raw_ref_fn(struct ref_store *ref_store,
-			    const char *refname, struct object_id *oid,
-			    struct strbuf *referent, unsigned int *type);
+typedef int read_raw_ref_fn(struct ref_store *ref_store, const char *refname,
+			    struct object_id *oid, struct strbuf *referent,
+			    unsigned int *type, int *failure_errno);
 
 struct ref_storage_be {
 	struct ref_storage_be *next;
@@ -683,7 +703,12 @@
 	/* The backend describing this ref_store's storage scheme: */
 	const struct ref_storage_be *be;
 
-	/* The gitdir that this ref_store applies to: */
+	struct repository *repo;
+
+	/*
+	 * The gitdir that this ref_store applies to. Note that this is not
+	 * necessarily repo->gitdir if the repo has multiple worktrees.
+	 */
 	char *gitdir;
 };
 
diff --git a/remote-curl.c b/remote-curl.c
index 6c320d5..d691563 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -185,8 +185,6 @@
 						 strbuf_detach(&unquoted, NULL));
 		}
 		return 0;
-
-#if LIBCURL_VERSION_NUM >= 0x070a08
 	} else if (!strcmp(name, "family")) {
 		if (!strcmp(value, "ipv4"))
 			git_curl_ipresolve = CURL_IPRESOLVE_V4;
@@ -197,7 +195,6 @@
 		else
 			return -1;
 		return 0;
-#endif /* LIBCURL_VERSION_NUM >= 0x070a08 */
 	} else if (!strcmp(name, "from-promisor")) {
 		options.from_promisor = 1;
 		return 0;
@@ -502,6 +499,10 @@
 		show_http_message(&type, &charset, &buffer);
 		die(_("Authentication failed for '%s'"),
 		    transport_anonymize_url(url.buf));
+	case HTTP_NOMATCHPUBLICKEY:
+		show_http_message(&type, &charset, &buffer);
+		die(_("unable to access '%s' with http.pinnedPubkey configuration: %s"),
+		    transport_anonymize_url(url.buf), curl_errorstr);
 	default:
 		show_http_message(&type, &charset, &buffer);
 		die(_("unable to access '%s': %s"),
@@ -709,7 +710,6 @@
 	return avail;
 }
 
-#ifndef NO_CURL_IOCTL
 static curlioerr rpc_ioctl(CURL *handle, int cmd, void *clientp)
 {
 	struct rpc_state *rpc = clientp;
@@ -730,7 +730,6 @@
 		return CURLIOE_UNKNOWNCMD;
 	}
 }
-#endif
 
 struct check_pktline_state {
 	char len_buf[4];
@@ -858,7 +857,7 @@
 	curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE, 4);
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
-	curl_easy_setopt(slot->curl, CURLOPT_FILE, &buf);
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, &buf);
 
 	err = run_slot(slot, results);
 
@@ -949,10 +948,8 @@
 		rpc->initial_buffer = 1;
 		curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, rpc_out);
 		curl_easy_setopt(slot->curl, CURLOPT_INFILE, rpc);
-#ifndef NO_CURL_IOCTL
 		curl_easy_setopt(slot->curl, CURLOPT_IOCTLFUNCTION, rpc_ioctl);
 		curl_easy_setopt(slot->curl, CURLOPT_IOCTLDATA, rpc);
-#endif
 		if (options.verbosity > 1) {
 			fprintf(stderr, "POST %s (chunked)\n", rpc->service_name);
 			fflush(stderr);
@@ -1023,7 +1020,7 @@
 	rpc_in_data.slot = slot;
 	rpc_in_data.check_pktline = stateless_connect;
 	memset(&rpc_in_data.pktline_state, 0, sizeof(rpc_in_data.pktline_state));
-	curl_easy_setopt(slot->curl, CURLOPT_FILE, &rpc_in_data);
+	curl_easy_setopt(slot->curl, CURLOPT_WRITEDATA, &rpc_in_data);
 	curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 0);
 
 
@@ -1091,7 +1088,7 @@
 		rpc->protocol_header = NULL;
 
 	while (!err) {
-		int n = packet_read(rpc->out, NULL, NULL, rpc->buf, rpc->alloc, 0);
+		int n = packet_read(rpc->out, rpc->buf, rpc->alloc, 0);
 		if (!n)
 			break;
 		rpc->pos = 0;
@@ -1485,8 +1482,8 @@
 	options.verbosity = 1;
 	options.progress = !!isatty(2);
 	options.thin = 1;
-	string_list_init(&options.deepen_not, 1);
-	string_list_init(&options.push_options, 1);
+	string_list_init_dup(&options.deepen_not);
+	string_list_init_dup(&options.push_options);
 
 	/*
 	 * Just report "remote-curl" here (folding all the various aliases
diff --git a/remote.c b/remote.c
index 40e785d..f958543 100644
--- a/remote.c
+++ b/remote.c
@@ -1111,7 +1111,7 @@
 		"Neither worked, so we gave up. You must fully qualify the ref."),
 	      dst_value, matched_src_name);
 
-	if (!advice_push_unqualified_ref_name)
+	if (!advice_enabled(ADVICE_PUSH_UNQUALIFIED_REF_NAME))
 		return;
 
 	if (get_oid(matched_src_name, &oid))
@@ -2118,7 +2118,7 @@
 		strbuf_addf(sb,
 			_("Your branch is based on '%s', but the upstream is gone.\n"),
 			base);
-		if (advice_status_hints)
+		if (advice_enabled(ADVICE_STATUS_HINTS))
 			strbuf_addstr(sb,
 				_("  (use \"git branch --unset-upstream\" to fixup)\n"));
 	} else if (!sti) {
@@ -2129,7 +2129,7 @@
 		strbuf_addf(sb,
 			    _("Your branch and '%s' refer to different commits.\n"),
 			    base);
-		if (advice_status_hints)
+		if (advice_enabled(ADVICE_STATUS_HINTS))
 			strbuf_addf(sb, _("  (use \"%s\" for details)\n"),
 				    "git status --ahead-behind");
 	} else if (!theirs) {
@@ -2138,7 +2138,7 @@
 			   "Your branch is ahead of '%s' by %d commits.\n",
 			   ours),
 			base, ours);
-		if (advice_status_hints)
+		if (advice_enabled(ADVICE_STATUS_HINTS))
 			strbuf_addstr(sb,
 				_("  (use \"git push\" to publish your local commits)\n"));
 	} else if (!ours) {
@@ -2149,7 +2149,7 @@
 			       "and can be fast-forwarded.\n",
 			   theirs),
 			base, theirs);
-		if (advice_status_hints)
+		if (advice_enabled(ADVICE_STATUS_HINTS))
 			strbuf_addstr(sb,
 				_("  (use \"git pull\" to update your local branch)\n"));
 	} else {
@@ -2162,7 +2162,7 @@
 			       "respectively.\n",
 			   ours + theirs),
 			base, ours, theirs);
-		if (advice_status_hints)
+		if (advice_enabled(ADVICE_STATUS_HINTS))
 			strbuf_addstr(sb,
 				_("  (use \"git pull\" to merge the remote branch into yours)\n"));
 	}
@@ -2403,7 +2403,7 @@
 	size_t nr, alloc;
 };
 
-#define REFLOG_COMMIT_ARRAY_INIT { NULL, 0, 0 }
+#define REFLOG_COMMIT_ARRAY_INIT { 0 }
 
 /* Append a commit to the array. */
 static void append_commit(struct reflog_commit_array *arr,
diff --git a/repo-settings.c b/repo-settings.c
index 0cfe8b7..b93e91a 100644
--- a/repo-settings.c
+++ b/repo-settings.c
@@ -3,40 +3,77 @@
 #include "repository.h"
 #include "midx.h"
 
-#define UPDATE_DEFAULT_BOOL(s,v) do { if (s == -1) { s = v; } } while(0)
+static void repo_cfg_bool(struct repository *r, const char *key, int *dest,
+			  int def)
+{
+	if (repo_config_get_bool(r, key, dest))
+		*dest = def;
+}
 
 void prepare_repo_settings(struct repository *r)
 {
+	int experimental;
 	int value;
 	char *strval;
+	int manyfiles;
 
-	if (r->settings.initialized)
+	if (r->settings.initialized++)
 		return;
 
 	/* Defaults */
-	memset(&r->settings, -1, sizeof(r->settings));
+	r->settings.index_version = -1;
+	r->settings.core_untracked_cache = UNTRACKED_CACHE_KEEP;
+	r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_DEFAULT;
 
-	if (!repo_config_get_bool(r, "core.commitgraph", &value))
-		r->settings.core_commit_graph = value;
-	if (!repo_config_get_bool(r, "commitgraph.readchangedpaths", &value))
-		r->settings.commit_graph_read_changed_paths = value;
-	if (!repo_config_get_bool(r, "gc.writecommitgraph", &value))
-		r->settings.gc_write_commit_graph = value;
-	UPDATE_DEFAULT_BOOL(r->settings.core_commit_graph, 1);
-	UPDATE_DEFAULT_BOOL(r->settings.commit_graph_read_changed_paths, 1);
-	UPDATE_DEFAULT_BOOL(r->settings.gc_write_commit_graph, 1);
+	/* Booleans config or default, cascades to other settings */
+	repo_cfg_bool(r, "feature.manyfiles", &manyfiles, 0);
+	repo_cfg_bool(r, "feature.experimental", &experimental, 0);
 
+	/* Defaults modified by feature.* */
+	if (experimental) {
+		r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_SKIPPING;
+	}
+	if (manyfiles) {
+		r->settings.index_version = 4;
+		r->settings.core_untracked_cache = UNTRACKED_CACHE_WRITE;
+	}
+
+	/* Boolean config or default, does not cascade (simple)  */
+	repo_cfg_bool(r, "core.commitgraph", &r->settings.core_commit_graph, 1);
+	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);
+	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);
+
+	/*
+	 * The GIT_TEST_MULTI_PACK_INDEX variable is special in that
+	 * either it *or* the config sets
+	 * r->settings.core_multi_pack_index if true. We don't take
+	 * the environment variable if it exists (even if false) over
+	 * any config, as in most other cases.
+	 */
+	if (git_env_bool(GIT_TEST_MULTI_PACK_INDEX, 0))
+		r->settings.core_multi_pack_index = 1;
+
+	/*
+	 * Non-boolean config
+	 */
 	if (!repo_config_get_int(r, "index.version", &value))
 		r->settings.index_version = value;
-	if (!repo_config_get_maybe_bool(r, "core.untrackedcache", &value)) {
-		if (value == 0)
-			r->settings.core_untracked_cache = UNTRACKED_CACHE_REMOVE;
-		else
-			r->settings.core_untracked_cache = UNTRACKED_CACHE_WRITE;
-	} else if (!repo_config_get_string(r, "core.untrackedcache", &strval)) {
-		if (!strcasecmp(strval, "keep"))
-			r->settings.core_untracked_cache = UNTRACKED_CACHE_KEEP;
 
+	if (!repo_config_get_string(r, "core.untrackedcache", &strval)) {
+		int v = git_parse_maybe_bool(strval);
+
+		/*
+		 * If it's set to "keep", or some other non-boolean
+		 * value then "v < 0". Then we do nothing and keep it
+		 * at the default of UNTRACKED_CACHE_KEEP.
+		 */
+		if (v >= 0)
+			r->settings.core_untracked_cache = v ?
+				UNTRACKED_CACHE_WRITE : UNTRACKED_CACHE_REMOVE;
 		free(strval);
 	}
 
@@ -45,39 +82,8 @@
 			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_SKIPPING;
 		else if (!strcasecmp(strval, "noop"))
 			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_NOOP;
-		else
-			r->settings.fetch_negotiation_algorithm = FETCH_NEGOTIATION_DEFAULT;
 	}
 
-	if (!repo_config_get_bool(r, "pack.usesparse", &value))
-		r->settings.pack_use_sparse = value;
-	UPDATE_DEFAULT_BOOL(r->settings.pack_use_sparse, 1);
-
-	value = git_env_bool(GIT_TEST_MULTI_PACK_INDEX, 0);
-	if (value || !repo_config_get_bool(r, "core.multipackindex", &value))
-		r->settings.core_multi_pack_index = value;
-	UPDATE_DEFAULT_BOOL(r->settings.core_multi_pack_index, 1);
-
-	if (!repo_config_get_bool(r, "feature.manyfiles", &value) && value) {
-		UPDATE_DEFAULT_BOOL(r->settings.index_version, 4);
-		UPDATE_DEFAULT_BOOL(r->settings.core_untracked_cache, UNTRACKED_CACHE_WRITE);
-	}
-
-	if (!repo_config_get_bool(r, "fetch.writecommitgraph", &value))
-		r->settings.fetch_write_commit_graph = value;
-	UPDATE_DEFAULT_BOOL(r->settings.fetch_write_commit_graph, 0);
-
-	if (!repo_config_get_bool(r, "feature.experimental", &value) && value)
-		UPDATE_DEFAULT_BOOL(r->settings.fetch_negotiation_algorithm, FETCH_NEGOTIATION_SKIPPING);
-
-	/* Hack for test programs like test-dump-untracked-cache */
-	if (ignore_untracked_cache_config)
-		r->settings.core_untracked_cache = UNTRACKED_CACHE_KEEP;
-	else
-		UPDATE_DEFAULT_BOOL(r->settings.core_untracked_cache, UNTRACKED_CACHE_KEEP);
-
-	UPDATE_DEFAULT_BOOL(r->settings.fetch_negotiation_algorithm, FETCH_NEGOTIATION_DEFAULT);
-
 	/*
 	 * This setting guards all index reads to require a full index
 	 * over a sparse index. After suitable guards are placed in the
@@ -85,11 +91,4 @@
 	 * removed.
 	 */
 	r->settings.command_requires_full_index = 1;
-
-	/*
-	 * Initialize this as off.
-	 */
-	r->settings.sparse_index = 0;
-	if (!repo_config_get_bool(r, "index.sparse", &value) && value)
-		r->settings.sparse_index = 1;
 }
diff --git a/repository.c b/repository.c
index b2bf44c..c5b90ba 100644
--- a/repository.c
+++ b/repository.c
@@ -190,19 +190,15 @@
 
 int repo_submodule_init(struct repository *subrepo,
 			struct repository *superproject,
-			const struct submodule *sub)
+			const char *path,
+			const struct object_id *treeish_name)
 {
 	struct strbuf gitdir = STRBUF_INIT;
 	struct strbuf worktree = STRBUF_INIT;
 	int ret = 0;
 
-	if (!sub) {
-		ret = -1;
-		goto out;
-	}
-
-	strbuf_repo_worktree_path(&gitdir, superproject, "%s/.git", sub->path);
-	strbuf_repo_worktree_path(&worktree, superproject, "%s", sub->path);
+	strbuf_repo_worktree_path(&gitdir, superproject, "%s/.git", path);
+	strbuf_repo_worktree_path(&worktree, superproject, "%s", path);
 
 	if (repo_init(subrepo, gitdir.buf, worktree.buf)) {
 		/*
@@ -212,9 +208,15 @@
 		 * in the superproject's 'modules' directory.  In this case the
 		 * submodule would not have a worktree.
 		 */
+		const struct submodule *sub =
+			submodule_from_path(superproject, treeish_name, path);
+		if (!sub) {
+			ret = -1;
+			goto out;
+		}
+
 		strbuf_reset(&gitdir);
-		strbuf_repo_git_path(&gitdir, superproject,
-				     "modules/%s", sub->name);
+		submodule_name_to_gitdir(&gitdir, superproject, sub->name);
 
 		if (repo_init(subrepo, gitdir.buf, NULL)) {
 			ret = -1;
@@ -225,7 +227,7 @@
 	subrepo->submodule_prefix = xstrfmt("%s%s/",
 					    superproject->submodule_prefix ?
 					    superproject->submodule_prefix :
-					    "", sub->path);
+					    "", path);
 
 out:
 	strbuf_release(&gitdir);
diff --git a/repository.h b/repository.h
index 3740c93..a057653 100644
--- a/repository.h
+++ b/repository.h
@@ -13,18 +13,15 @@
 struct promisor_remote_config;
 
 enum untracked_cache_setting {
-	UNTRACKED_CACHE_UNSET = -1,
-	UNTRACKED_CACHE_REMOVE = 0,
-	UNTRACKED_CACHE_KEEP = 1,
-	UNTRACKED_CACHE_WRITE = 2
+	UNTRACKED_CACHE_KEEP,
+	UNTRACKED_CACHE_REMOVE,
+	UNTRACKED_CACHE_WRITE,
 };
 
 enum fetch_negotiation_setting {
-	FETCH_NEGOTIATION_UNSET = -1,
-	FETCH_NEGOTIATION_NONE = 0,
-	FETCH_NEGOTIATION_DEFAULT = 1,
-	FETCH_NEGOTIATION_SKIPPING = 2,
-	FETCH_NEGOTIATION_NOOP = 3,
+	FETCH_NEGOTIATION_DEFAULT,
+	FETCH_NEGOTIATION_SKIPPING,
+	FETCH_NEGOTIATION_NOOP,
 };
 
 struct repo_settings {
@@ -34,6 +31,8 @@
 	int commit_graph_read_changed_paths;
 	int gc_write_commit_graph;
 	int fetch_write_commit_graph;
+	int command_requires_full_index;
+	int sparse_index;
 
 	int index_version;
 	enum untracked_cache_setting core_untracked_cache;
@@ -42,9 +41,6 @@
 	enum fetch_negotiation_setting fetch_negotiation_algorithm;
 
 	int core_multi_pack_index;
-
-	unsigned command_requires_full_index:1,
-		 sparse_index:1;
 };
 
 struct repository {
@@ -172,15 +168,18 @@
 int repo_init(struct repository *r, const char *gitdir, const char *worktree);
 
 /*
- * Initialize the repository 'subrepo' as the submodule given by the
- * struct submodule 'sub' in parent repository 'superproject'.
- * Return 0 upon success and a non-zero value upon failure, which may happen
- * if the submodule is not found, or 'sub' is NULL.
+ * Initialize the repository 'subrepo' as the submodule at the given path. If
+ * the submodule's gitdir cannot be found at <path>/.git, this function calls
+ * submodule_from_path() to try to find it. treeish_name is only used if
+ * submodule_from_path() needs to be called; see its documentation for more
+ * information.
+ * Return 0 upon success and a non-zero value upon failure.
  */
-struct submodule;
+struct object_id;
 int repo_submodule_init(struct repository *subrepo,
 			struct repository *superproject,
-			const struct submodule *sub);
+			const char *path,
+			const struct object_id *treeish_name);
 void repo_clear(struct repository *repo);
 
 /*
diff --git a/reset.c b/reset.c
index 79310ae..f214df3 100644
--- a/reset.c
+++ b/reset.c
@@ -56,9 +56,10 @@
 	unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;
 	unpack_tree_opts.update = 1;
 	unpack_tree_opts.merge = 1;
+	unpack_tree_opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
 	init_checkout_metadata(&unpack_tree_opts.meta, switch_to_branch, oid, NULL);
 	if (!detach_head)
-		unpack_tree_opts.reset = 1;
+		unpack_tree_opts.reset = UNPACK_RESET_PROTECT_UNTRACKED;
 
 	if (repo_read_index_unmerged(r) < 0) {
 		ret = error(_("could not read index"));
diff --git a/revision.c b/revision.c
index cddd054..ab7c135 100644
--- a/revision.c
+++ b/revision.c
@@ -249,7 +249,7 @@
 	struct commit **items;
 	size_t nr, alloc;
 };
-#define COMMIT_STACK_INIT { NULL, 0, 0 }
+#define COMMIT_STACK_INIT { 0 }
 
 static void commit_stack_push(struct commit_stack *stack, struct commit *commit)
 {
@@ -360,20 +360,18 @@
 				    unsigned int flags)
 {
 	struct object *object;
+	struct commit *commit;
 
 	/*
-	 * If the repository has commit graphs, repo_parse_commit() avoids
-	 * reading the object buffer, so use it whenever possible.
+	 * 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.
 	 */
-	if (oid_object_info(revs->repo, oid, NULL) == OBJ_COMMIT) {
-		struct commit *c = lookup_commit(revs->repo, oid);
-		if (!repo_parse_commit(revs->repo, c))
-			object = (struct object *) c;
-		else
-			object = NULL;
-	} else {
+	commit = lookup_commit_in_graph(revs->repo, oid);
+	if (commit)
+		object = &commit->object;
+	else
 		object = parse_object(revs->repo, oid);
-	}
 
 	if (!object) {
 		if (revs->ignore_missing)
@@ -1534,7 +1532,7 @@
 
 	object = get_reference(cb->all_revs, path, oid, cb->all_flags);
 	add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
-	add_pending_oid(cb->all_revs, path, oid, cb->all_flags);
+	add_pending_object(cb->all_revs, object, path);
 	return 0;
 }
 
@@ -2256,6 +2254,10 @@
 	} else if (!strcmp(arg, "--author-date-order")) {
 		revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
 		revs->topo_order = 1;
+	} else if (!strcmp(arg, "--unsorted-input")) {
+		if (revs->no_walk)
+			die(_("--unsorted-input is incompatible with --no-walk"));
+		revs->unsorted_input = 1;
 	} else if (!strcmp(arg, "--early-output")) {
 		revs->early_output = 100;
 		revs->topo_order = 1;
@@ -2546,7 +2548,7 @@
 	struct strbuf bisect_refs = STRBUF_INIT;
 	int status;
 	strbuf_addf(&bisect_refs, "refs/bisect/%s", term);
-	status = refs_for_each_fullref_in(refs, bisect_refs.buf, fn, cb_data, 0);
+	status = refs_for_each_fullref_in(refs, bisect_refs.buf, fn, cb_data);
 	strbuf_release(&bisect_refs);
 	return status;
 }
@@ -2561,8 +2563,7 @@
 	return for_each_bisect_ref(refs, fn, cb_data, term_good);
 }
 
-static int handle_revision_pseudo_opt(const char *submodule,
-				      struct rev_info *revs,
+static int handle_revision_pseudo_opt(struct rev_info *revs,
 				      const char **argv, int *flags)
 {
 	const char *arg = argv[0];
@@ -2570,7 +2571,7 @@
 	struct ref_store *refs;
 	int argcount;
 
-	if (submodule) {
+	if (revs->repo != the_repository) {
 		/*
 		 * We need some something like get_submodule_worktrees()
 		 * before we can go through all worktrees of a submodule,
@@ -2579,9 +2580,8 @@
 		 */
 		if (!revs->single_worktree)
 			BUG("--single-worktree cannot be used together with submodule");
-		refs = get_submodule_ref_store(submodule);
-	} else
-		refs = get_main_ref_store(revs->repo);
+	}
+	refs = get_main_ref_store(revs->repo);
 
 	/*
 	 * NOTE!
@@ -2651,16 +2651,22 @@
 	} else if (!strcmp(arg, "--not")) {
 		*flags ^= UNINTERESTING | BOTTOM;
 	} else if (!strcmp(arg, "--no-walk")) {
-		revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
+		if (!revs->no_walk && revs->unsorted_input)
+			die(_("--no-walk is incompatible with --unsorted-input"));
+		revs->no_walk = 1;
 	} else if (skip_prefix(arg, "--no-walk=", &optarg)) {
+		if (!revs->no_walk && revs->unsorted_input)
+			die(_("--no-walk is incompatible with --unsorted-input"));
+
 		/*
 		 * Detached form ("--no-walk X" as opposed to "--no-walk=X")
 		 * not allowed, since the argument is optional.
 		 */
+		revs->no_walk = 1;
 		if (!strcmp(optarg, "sorted"))
-			revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
+			revs->unsorted_input = 0;
 		else if (!strcmp(optarg, "unsorted"))
-			revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
+			revs->unsorted_input = 1;
 		else
 			return error("invalid argument to --no-walk");
 	} else if (!strcmp(arg, "--do-walk")) {
@@ -2699,12 +2705,8 @@
 {
 	int i, flags, left, seen_dashdash, revarg_opt;
 	struct strvec prune_data = STRVEC_INIT;
-	const char *submodule = NULL;
 	int seen_end_of_options = 0;
 
-	if (opt)
-		submodule = opt->submodule;
-
 	/* First, search for "--" */
 	if (opt && opt->assume_dashdash) {
 		seen_dashdash = 1;
@@ -2733,7 +2735,7 @@
 		if (!seen_end_of_options && *arg == '-') {
 			int opts;
 
-			opts = handle_revision_pseudo_opt(submodule,
+			opts = handle_revision_pseudo_opt(
 						revs, argv + i,
 						&flags);
 			if (opts > 0) {
@@ -3584,7 +3586,7 @@
 
 	if (!revs->reflog_info)
 		prepare_to_use_bloom_filter(revs);
-	if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
+	if (!revs->unsorted_input)
 		commit_list_sort_by_date(&revs->commits);
 	if (revs->no_walk)
 		return 0;
diff --git a/revision.h b/revision.h
index fbb068d..5578bb4 100644
--- a/revision.h
+++ b/revision.h
@@ -79,10 +79,6 @@
 	} *rev;
 };
 
-#define REVISION_WALK_WALK 0
-#define REVISION_WALK_NO_WALK_SORTED 1
-#define REVISION_WALK_NO_WALK_UNSORTED 2
-
 struct oidset;
 struct topo_walk_info;
 
@@ -129,7 +125,8 @@
 	/* Traversal flags */
 	unsigned int	dense:1,
 			prune:1,
-			no_walk:2,
+			no_walk:1,
+			unsorted_input:1,
 			remove_empty_trees:1,
 			simplify_history:1,
 			show_pulls:1,
@@ -339,7 +336,6 @@
 struct setup_revision_opt {
 	const char *def;
 	void (*tweak)(struct rev_info *, struct setup_revision_opt *);
-	const char *submodule;	/* TODO: drop this and use rev_info->repo */
 	unsigned int	assume_dashdash:1,
 			allow_exclude_promisor_objects:1;
 	unsigned revarg_opt;
diff --git a/run-command.c b/run-command.c
index 2961f7e..7ef5cc7 100644
--- a/run-command.c
+++ b/run-command.c
@@ -8,6 +8,8 @@
 #include "string-list.h"
 #include "quote.h"
 #include "config.h"
+#include "packfile.h"
+#include "hook.h"
 
 void child_process_init(struct child_process *child)
 {
@@ -210,9 +212,9 @@
 	return NULL;
 }
 
-static int exists_in_PATH(const char *file)
+int exists_in_PATH(const char *command)
 {
-	char *r = locate_in_PATH(file);
+	char *r = locate_in_PATH(command);
 	int found = r != NULL;
 	free(r);
 	return found;
@@ -740,6 +742,9 @@
 
 	fflush(NULL);
 
+	if (cmd->close_object_store)
+		close_object_store(the_repository->objects);
+
 #ifndef GIT_WINDOWS_NATIVE
 {
 	int notify_pipe[2];
@@ -1042,6 +1047,7 @@
 	cmd.use_shell = opt & RUN_USING_SHELL ? 1 : 0;
 	cmd.clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 	cmd.wait_after_clean = opt & RUN_WAIT_AFTER_CLEAN ? 1 : 0;
+	cmd.close_object_store = opt & RUN_CLOSE_OBJECT_STORE ? 1 : 0;
 	cmd.dir = dir;
 	cmd.env = env;
 	cmd.trace2_child_class = tr2_class;
@@ -1317,40 +1323,6 @@
 #endif
 }
 
-const char *find_hook(const char *name)
-{
-	static struct strbuf path = STRBUF_INIT;
-
-	strbuf_reset(&path);
-	strbuf_git_path(&path, "hooks/%s", name);
-	if (access(path.buf, X_OK) < 0) {
-		int err = errno;
-
-#ifdef STRIP_EXTENSION
-		strbuf_addstr(&path, STRIP_EXTENSION);
-		if (access(path.buf, X_OK) >= 0)
-			return path.buf;
-		if (errno == EACCES)
-			err = errno;
-#endif
-
-		if (err == EACCES && advice_ignored_hook) {
-			static struct string_list advise_given = STRING_LIST_INIT_DUP;
-
-			if (!string_list_lookup(&advise_given, name)) {
-				string_list_insert(&advise_given, name);
-				advise(_("The '%s' hook was ignored because "
-					 "it's not set as executable.\n"
-					 "You can disable this warning with "
-					 "`git config advice.ignoredHook false`."),
-				       path.buf);
-			}
-		}
-		return NULL;
-	}
-	return path.buf;
-}
-
 int run_hook_ve(const char *const *env, const char *name, va_list args)
 {
 	struct child_process hook = CHILD_PROCESS_INIT;
@@ -1884,6 +1856,7 @@
 		return 0;
 
 	maint.git_cmd = 1;
+	maint.close_object_store = 1;
 	strvec_pushl(&maint.args, "maintenance", "run", "--auto", NULL);
 	strvec_push(&maint.args, quiet ? "--quiet" : "--no-quiet");
 
@@ -1901,3 +1874,132 @@
 	}
 	strvec_pushf(env_array, "%s=%s", GIT_DIR_ENVIRONMENT, new_git_dir);
 }
+
+enum start_bg_result start_bg_command(struct child_process *cmd,
+				      start_bg_wait_cb *wait_cb,
+				      void *cb_data,
+				      unsigned int timeout_sec)
+{
+	enum start_bg_result sbgr = SBGR_ERROR;
+	int ret;
+	int wait_status;
+	pid_t pid_seen;
+	time_t time_limit;
+
+	/*
+	 * We do not allow clean-on-exit because the child process
+	 * should persist in the background and possibly/probably
+	 * after this process exits.  So we don't want to kill the
+	 * child during our atexit routine.
+	 */
+	if (cmd->clean_on_exit)
+		BUG("start_bg_command() does not allow non-zero clean_on_exit");
+
+	if (!cmd->trace2_child_class)
+		cmd->trace2_child_class = "background";
+
+	ret = start_command(cmd);
+	if (ret) {
+		/*
+		 * We assume that if `start_command()` fails, we
+		 * either get a complete `trace2_child_start() /
+		 * trace2_child_exit()` pair or it fails before the
+		 * `trace2_child_start()` is emitted, so we do not
+		 * need to worry about it here.
+		 *
+		 * We also assume that `start_command()` does not add
+		 * us to the cleanup list.  And that it calls
+		 * calls `child_process_clear()`.
+		 */
+		sbgr = SBGR_ERROR;
+		goto done;
+	}
+
+	time(&time_limit);
+	time_limit += timeout_sec;
+
+wait:
+	pid_seen = waitpid(cmd->pid, &wait_status, WNOHANG);
+
+	if (!pid_seen) {
+		/*
+		 * The child is currently running.  Ask the callback
+		 * if the child is ready to do work or whether we
+		 * should keep waiting for it to boot up.
+		 */
+		ret = (*wait_cb)(cmd, cb_data);
+		if (!ret) {
+			/*
+			 * The child is running and "ready".
+			 */
+			trace2_child_ready(cmd, "ready");
+			sbgr = SBGR_READY;
+			goto done;
+		} else if (ret > 0) {
+			/*
+			 * The callback said to give it more time to boot up
+			 * (subject to our timeout limit).
+			 */
+			time_t now;
+
+			time(&now);
+			if (now < time_limit)
+				goto wait;
+
+			/*
+			 * Our timeout has expired.  We don't try to
+			 * kill the child, but rather let it continue
+			 * (hopefully) trying to startup.
+			 */
+			trace2_child_ready(cmd, "timeout");
+			sbgr = SBGR_TIMEOUT;
+			goto done;
+		} else {
+			/*
+			 * The cb gave up on this child.  It is still running,
+			 * but our cb got an error trying to probe it.
+			 */
+			trace2_child_ready(cmd, "error");
+			sbgr = SBGR_CB_ERROR;
+			goto done;
+		}
+	}
+
+	else if (pid_seen == cmd->pid) {
+		int child_code = -1;
+
+		/*
+		 * The child started, but exited or was terminated
+		 * before becoming "ready".
+		 *
+		 * We try to match the behavior of `wait_or_whine()`
+		 * WRT the handling of WIFSIGNALED() and WIFEXITED()
+		 * and convert the child's status to a return code for
+		 * tracing purposes and emit the `trace2_child_exit()`
+		 * event.
+		 *
+		 * We do not want the wait_or_whine() error message
+		 * because we will be called by client-side library
+		 * routines.
+		 */
+		if (WIFEXITED(wait_status))
+			child_code = WEXITSTATUS(wait_status);
+		else if (WIFSIGNALED(wait_status))
+			child_code = WTERMSIG(wait_status) + 128;
+		trace2_child_exit(cmd, child_code);
+
+		sbgr = SBGR_DIED;
+		goto done;
+	}
+
+	else if (pid_seen < 0 && errno == EINTR)
+		goto wait;
+
+	trace2_child_exit(cmd, -1);
+	sbgr = SBGR_ERROR;
+
+done:
+	child_process_clear(cmd);
+	invalidate_lstat_cache();
+	return sbgr;
+}
diff --git a/run-command.h b/run-command.h
index af12967..4987826 100644
--- a/run-command.h
+++ b/run-command.h
@@ -134,6 +134,14 @@
 	 */
 	unsigned use_shell:1;
 
+	/**
+	 * Release any open file handles to the object store before running
+	 * the command; This is necessary e.g. when the spawned process may
+	 * want to repack because that would delete `.pack` files (and on
+	 * Windows, you cannot delete files that are still in use).
+	 */
+	unsigned close_object_store:1;
+
 	unsigned stdout_to_stderr:1;
 	unsigned clean_on_exit:1;
 	unsigned wait_after_clean:1;
@@ -183,6 +191,18 @@
 int is_executable(const char *name);
 
 /**
+ * Check if the command exists on $PATH. This emulates the path search that
+ * execvp would perform, without actually executing the command so it
+ * can be used before fork() to prepare to run a command using
+ * execve() or after execvp() to diagnose why it failed.
+ *
+ * The caller should ensure that command contains no directory separators.
+ *
+ * Returns 1 if it is found in $PATH or 0 if the command could not be found.
+ */
+int exists_in_PATH(const char *command);
+
+/**
  * Start a sub-process. Takes a pointer to a `struct child_process`
  * that specifies the details and returns pipe FDs (if requested).
  * See below for details.
@@ -204,13 +224,6 @@
  */
 int run_command(struct child_process *);
 
-/*
- * Returns the path to the hook file, or NULL if the hook is missing
- * or disabled. Note that this points to static storage that will be
- * overwritten by further calls to find_hook and run_hook_*.
- */
-const char *find_hook(const char *name);
-
 /**
  * Run a hook.
  * The first argument is a pathname to an index file, or NULL
@@ -233,13 +246,14 @@
  */
 int run_auto_maintenance(int quiet);
 
-#define RUN_COMMAND_NO_STDIN 1
-#define RUN_GIT_CMD	     2	/*If this is to be git sub-command */
-#define RUN_COMMAND_STDOUT_TO_STDERR 4
-#define RUN_SILENT_EXEC_FAILURE 8
-#define RUN_USING_SHELL 16
-#define RUN_CLEAN_ON_EXIT 32
-#define RUN_WAIT_AFTER_CLEAN 64
+#define RUN_COMMAND_NO_STDIN		(1<<0)
+#define RUN_GIT_CMD			(1<<1)
+#define RUN_COMMAND_STDOUT_TO_STDERR	(1<<2)
+#define RUN_SILENT_EXEC_FAILURE		(1<<3)
+#define RUN_USING_SHELL			(1<<4)
+#define RUN_CLEAN_ON_EXIT		(1<<5)
+#define RUN_WAIT_AFTER_CLEAN		(1<<6)
+#define RUN_CLOSE_OBJECT_STORE		(1<<7)
 
 /**
  * Convenience functions that encapsulate a sequence of
@@ -496,4 +510,61 @@
  */
 void prepare_other_repo_env(struct strvec *env_array, const char *new_git_dir);
 
+/**
+ * Possible return values for start_bg_command().
+ */
+enum start_bg_result {
+	/* child process is "ready" */
+	SBGR_READY = 0,
+
+	/* child process could not be started */
+	SBGR_ERROR,
+
+	/* callback error when testing for "ready" */
+	SBGR_CB_ERROR,
+
+	/* timeout expired waiting for child to become "ready" */
+	SBGR_TIMEOUT,
+
+	/* child process exited or was signalled before becomming "ready" */
+	SBGR_DIED,
+};
+
+/**
+ * Callback used by start_bg_command() to ask whether the
+ * child process is ready or needs more time to become "ready".
+ *
+ * The callback will receive the cmd and cb_data arguments given to
+ * start_bg_command().
+ *
+ * Returns 1 is child needs more time (subject to the requested timeout).
+ * Returns 0 if child is "ready".
+ * Returns -1 on any error and cause start_bg_command() to also error out.
+ */
+typedef int(start_bg_wait_cb)(const struct child_process *cmd, void *cb_data);
+
+/**
+ * Start a command in the background.  Wait long enough for the child
+ * to become "ready" (as defined by the provided callback).  Capture
+ * immediate errors (like failure to start) and any immediate exit
+ * status (such as a shutdown/signal before the child became "ready")
+ * and return this like start_command().
+ *
+ * We run a custom wait loop using the provided callback to wait for
+ * the child to start and become "ready".  This is limited by the given
+ * timeout value.
+ *
+ * If the child does successfully start and become "ready", we orphan
+ * it into the background.
+ *
+ * The caller must not call finish_command().
+ *
+ * The opaque cb_data argument will be forwarded to the callback for
+ * any instance data that it might require.  This may be NULL.
+ */
+enum start_bg_result start_bg_command(struct child_process *cmd,
+				      start_bg_wait_cb *wait_cb,
+				      void *cb_data,
+				      unsigned int timeout_sec);
+
 #endif
diff --git a/send-pack.c b/send-pack.c
index b3a495b..bc0fcdb 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -341,13 +341,13 @@
 {
 	const struct ref *ref;
 	struct string_list_item *item;
-	char *signing_key = xstrdup(get_signing_key());
+	char *signing_key_id = xstrdup(get_signing_key_id());
 	const char *cp, *np;
 	struct strbuf cert = STRBUF_INIT;
 	int update_seen = 0;
 
 	strbuf_addstr(&cert, "certificate version 0.1\n");
-	strbuf_addf(&cert, "pusher %s ", signing_key);
+	strbuf_addf(&cert, "pusher %s ", signing_key_id);
 	datestamp(&cert);
 	strbuf_addch(&cert, '\n');
 	if (args->url && *args->url) {
@@ -374,7 +374,7 @@
 	if (!update_seen)
 		goto free_return;
 
-	if (sign_buffer(&cert, &cert, signing_key))
+	if (sign_buffer(&cert, &cert, get_signing_key()))
 		die(_("failed to sign the push certificate"));
 
 	packet_buf_write(req_buf, "push-cert%c%s", 0, cap_string);
@@ -386,7 +386,7 @@
 	packet_buf_write(req_buf, "push-cert-end\n");
 
 free_return:
-	free(signing_key);
+	free(signing_key_id);
 	strbuf_release(&cert);
 	return update_seen;
 }
diff --git a/sequencer.c b/sequencer.c
index e4627d9..cd2aabf 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -8,6 +8,7 @@
 #include "sequencer.h"
 #include "tag.h"
 #include "run-command.h"
+#include "hook.h"
 #include "exec-cmd.h"
 #include "utf8.h"
 #include "cache-tree.h"
@@ -403,7 +404,7 @@
 	char *msg = getenv("GIT_CHERRY_PICK_HELP");
 
 	if (msg) {
-		fprintf(stderr, "%s\n", msg);
+		advise("%s\n", msg);
 		/*
 		 * A conflict has occurred but the porcelain
 		 * (typically rebase --interactive) wants to take care
@@ -418,10 +419,22 @@
 		if (opts->no_commit)
 			advise(_("after resolving the conflicts, mark the corrected paths\n"
 				 "with 'git add <paths>' or 'git rm <paths>'"));
+		else if (opts->action == REPLAY_PICK)
+			advise(_("After resolving the conflicts, mark them with\n"
+				 "\"git add/rm <pathspec>\", then run\n"
+				 "\"git cherry-pick --continue\".\n"
+				 "You can instead skip this commit with \"git cherry-pick --skip\".\n"
+				 "To abort and get back to the state before \"git cherry-pick\",\n"
+				 "run \"git cherry-pick --abort\"."));
+		else if (opts->action == REPLAY_REVERT)
+			advise(_("After resolving the conflicts, mark them with\n"
+				 "\"git add/rm <pathspec>\", then run\n"
+				 "\"git revert --continue\".\n"
+				 "You can instead skip this commit with \"git revert --skip\".\n"
+				 "To abort and get back to the state before \"git revert\",\n"
+				 "run \"git revert --abort\"."));
 		else
-			advise(_("after resolving the conflicts, mark the corrected paths\n"
-				 "with 'git add <paths>' or 'git rm <paths>'\n"
-				 "and commit the result with 'git commit'"));
+			BUG("unexpected pick action in print_advice()");
 	}
 }
 
@@ -486,7 +499,7 @@
 	error(_("your local changes would be overwritten by %s."),
 		_(action_name(opts)));
 
-	if (advice_commit_before_merge)
+	if (advice_enabled(ADVICE_COMMIT_BEFORE_MERGE))
 		advise(_("commit your changes or stash them to proceed."));
 	return -1;
 }
@@ -636,7 +649,7 @@
 	for (i = 0; i < opts->xopts_nr; i++)
 		parse_merge_opt(&o, opts->xopts[i]);
 
-	if (opts->strategy && !strcmp(opts->strategy, "ort")) {
+	if (!opts->strategy || !strcmp(opts->strategy, "ort")) {
 		memset(&result, 0, sizeof(result));
 		merge_incore_nonrecursive(&o, base_tree, head_tree, next_tree,
 					    &result);
@@ -652,6 +665,7 @@
 		merge_switch_to_result(&o, head_tree, &result, 1, show_output);
 		clean = result.clean;
 	} else {
+		ensure_full_index(r->index);
 		clean = merge_trees(&o, head_tree, next_tree, base_tree);
 		if (is_rebase_i(opts) && clean <= 0)
 			fputs(o.obuf.buf, stdout);
@@ -1242,7 +1256,7 @@
 
 static const char *implicit_ident_advice(void)
 {
-	char *user_config = expand_user_path("~/.gitconfig", 0);
+	char *user_config = interpolate_path("~/.gitconfig", 0);
 	char *xdg_config = xdg_config_home("config");
 	int config_exists = file_exists(user_config) || file_exists(xdg_config);
 
@@ -1294,7 +1308,7 @@
 	if (!committer_ident_sufficiently_given()) {
 		strbuf_addstr(&format, "\n Committer: ");
 		strbuf_addbuf_percentquote(&format, &committer_ident);
-		if (advice_implicit_identity) {
+		if (advice_enabled(ADVICE_IMPLICIT_IDENTITY)) {
 			strbuf_addch(&format, '\n');
 			strbuf_addstr(&format, implicit_ident_advice());
 		}
@@ -1446,7 +1460,7 @@
 		}
 	}
 
-	if (find_hook("prepare-commit-msg")) {
+	if (hook_exists("prepare-commit-msg")) {
 		res = run_prepare_commit_msg_hook(r, msg, hook_commit);
 		if (res)
 			goto out;
@@ -2347,6 +2361,7 @@
 			_(action_name(opts)));
 	}
 	refresh_index(r->index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
+
 	if (index_fd >= 0) {
 		if (write_locked_index(r->index, &index_lock,
 				       COMMIT_LOCK | SKIP_IF_UNCHANGED)) {
@@ -2354,6 +2369,13 @@
 				_(action_name(opts)));
 		}
 	}
+
+	/*
+	 * If we are resolving merges in any way other than "ort", then
+	 * expand the sparse index.
+	 */
+	if (opts->strategy && strcmp(opts->strategy, "ort"))
+		ensure_full_index(r->index);
 	return 0;
 }
 
@@ -2672,7 +2694,6 @@
 			      struct todo_list *todo_list,
 			      struct replay_opts *opts)
 {
-	struct stat st;
 	const char *todo_file = get_todo_path(opts);
 	int res;
 
@@ -2680,11 +2701,6 @@
 	if (strbuf_read_file_or_whine(&todo_list->buf, todo_file) < 0)
 		return -1;
 
-	res = stat(todo_file, &st);
-	if (res)
-		return error(_("could not stat '%s'"), todo_file);
-	fill_stat_data(&todo_list->stat, &st);
-
 	res = todo_list_parse_insn_buffer(r, todo_list->buf.buf, todo_list);
 	if (res) {
 		if (is_rebase_i(opts))
@@ -3042,7 +3058,7 @@
 	}
 	if (in_progress_error) {
 		error("%s", in_progress_error);
-		if (advice_sequencer_in_use)
+		if (advice_enabled(ADVICE_SEQUENCER_IN_USE))
 			advise(in_progress_advice,
 				advise_skip ? "--skip | " : "");
 		return -1;
@@ -3246,7 +3262,7 @@
 give_advice:
 	error(_("there is nothing to skip"));
 
-	if (advice_resolve_conflict) {
+	if (advice_enabled(ADVICE_RESOLVE_CONFLICT)) {
 		advise(_("have you committed already?\n"
 			 "try \"git %s --continue\""),
 			 action == REPLAY_REVERT ? "revert" : "cherry-pick");
@@ -3629,9 +3645,9 @@
 	struct strbuf ref_name = STRBUF_INIT;
 	struct object_id oid;
 	struct lock_file lock = LOCK_INIT;
-	struct tree_desc desc;
+	struct tree_desc desc = { 0 };
 	struct tree *tree;
-	struct unpack_trees_options unpack_tree_opts;
+	struct unpack_trees_options unpack_tree_opts = { 0 };
 	int ret = 0;
 
 	if (repo_hold_locked_index(r, &lock, LOCK_REPORT_ON_ERROR) < 0)
@@ -3663,14 +3679,11 @@
 		strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
 		if (get_oid(ref_name.buf, &oid) &&
 		    get_oid(ref_name.buf + strlen("refs/rewritten/"), &oid)) {
-			error(_("could not read '%s'"), ref_name.buf);
-			rollback_lock_file(&lock);
-			strbuf_release(&ref_name);
-			return -1;
+			ret = error(_("could not read '%s'"), ref_name.buf);
+			goto cleanup;
 		}
 	}
 
-	memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
 	setup_unpack_trees_porcelain(&unpack_tree_opts, "reset");
 	unpack_tree_opts.head_idx = 1;
 	unpack_tree_opts.src_index = r->index;
@@ -3678,27 +3691,22 @@
 	unpack_tree_opts.fn = oneway_merge;
 	unpack_tree_opts.merge = 1;
 	unpack_tree_opts.update = 1;
+	unpack_tree_opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
 	init_checkout_metadata(&unpack_tree_opts.meta, name, &oid, NULL);
 
 	if (repo_read_index_unmerged(r)) {
-		rollback_lock_file(&lock);
-		strbuf_release(&ref_name);
-		return error_resolve_conflict(_(action_name(opts)));
+		ret = error_resolve_conflict(_(action_name(opts)));
+		goto cleanup;
 	}
 
 	if (!fill_tree_descriptor(r, &desc, &oid)) {
-		error(_("failed to find tree of %s"), oid_to_hex(&oid));
-		rollback_lock_file(&lock);
-		free((void *)desc.buffer);
-		strbuf_release(&ref_name);
-		return -1;
+		ret = error(_("failed to find tree of %s"), oid_to_hex(&oid));
+		goto cleanup;
 	}
 
 	if (unpack_trees(1, &desc, &unpack_tree_opts)) {
-		rollback_lock_file(&lock);
-		free((void *)desc.buffer);
-		strbuf_release(&ref_name);
-		return -1;
+		ret = -1;
+		goto cleanup;
 	}
 
 	tree = parse_tree_indirect(&oid);
@@ -3706,14 +3714,17 @@
 
 	if (write_locked_index(r->index, &lock, COMMIT_LOCK) < 0)
 		ret = error(_("could not write index"));
-	free((void *)desc.buffer);
 
 	if (!ret)
 		ret = update_ref(reflog_message(opts, "reset", "'%.*s'",
 						len, name), "HEAD", &oid,
 				 NULL, 0, UPDATE_REFS_MSG_ON_ERR);
-
+cleanup:
+	free((void *)desc.buffer);
+	if (ret < 0)
+		rollback_lock_file(&lock);
 	strbuf_release(&ref_name);
+	clear_unpack_trees_porcelain(&unpack_tree_opts);
 	return ret;
 }
 
@@ -3990,7 +4001,7 @@
 	o.branch2 = ref_name.buf;
 	o.buffer_output = 2;
 
-	if (opts->strategy && !strcmp(opts->strategy, "ort")) {
+	if (!opts->strategy || !strcmp(opts->strategy, "ort")) {
 		/*
 		 * TODO: Should use merge_incore_recursive() and
 		 * merge_switch_to_result(), skipping the call to
@@ -4263,6 +4274,30 @@
 
 }
 
+static int reread_todo_if_changed(struct repository *r,
+				  struct todo_list *todo_list,
+				  struct replay_opts *opts)
+{
+	int offset;
+	struct strbuf buf = STRBUF_INIT;
+
+	if (strbuf_read_file_or_whine(&buf, get_todo_path(opts)) < 0)
+		return -1;
+	offset = get_item_line_offset(todo_list, todo_list->current + 1);
+	if (buf.len != todo_list->buf.len - offset ||
+	    memcmp(buf.buf, todo_list->buf.buf + offset, buf.len)) {
+		/* Reread the todo file if it has changed. */
+		todo_list_release(todo_list);
+		if (read_populate_todo(r, todo_list, opts))
+			return -1; /* message was printed */
+		/* `current` will be incremented on return */
+		todo_list->current = -1;
+	}
+	strbuf_release(&buf);
+
+	return 0;
+}
+
 static const char rescheduled_advice[] =
 N_("Could not execute the todo command\n"
 "\n"
@@ -4441,20 +4476,9 @@
 							item->commit,
 							arg, item->arg_len,
 							opts, res, 0);
-		} else if (is_rebase_i(opts) && check_todo && !res) {
-			struct stat st;
-
-			if (stat(get_todo_path(opts), &st)) {
-				res = error_errno(_("could not stat '%s'"),
-						  get_todo_path(opts));
-			} else if (match_stat_data(&todo_list->stat, &st)) {
-				/* Reread the todo file if it has changed. */
-				todo_list_release(todo_list);
-				if (read_populate_todo(r, todo_list, opts))
-					res = -1; /* message was printed */
-				/* `current` will be incremented below */
-				todo_list->current = -1;
-			}
+		} else if (is_rebase_i(opts) && check_todo && !res &&
+			   reread_todo_if_changed(r, todo_list, opts)) {
+			return -1;
 		}
 
 		todo_list->current++;
@@ -5110,6 +5134,7 @@
 	int keep_empty = flags & TODO_LIST_KEEP_EMPTY;
 	int rebase_cousins = flags & TODO_LIST_REBASE_COUSINS;
 	int root_with_onto = flags & TODO_LIST_ROOT_WITH_ONTO;
+	int skipped_commit = 0;
 	struct strbuf buf = STRBUF_INIT, oneline = STRBUF_INIT;
 	struct strbuf label = STRBUF_INIT;
 	struct commit_list *commits = NULL, **tail = &commits, *iter;
@@ -5160,8 +5185,13 @@
 		oidset_insert(&interesting, &commit->object.oid);
 
 		is_empty = is_original_commit_empty(commit);
-		if (!is_empty && (commit->object.flags & PATCHSAME))
+		if (!is_empty && (commit->object.flags & PATCHSAME)) {
+			if (flags & TODO_LIST_WARN_SKIPPED_CHERRY_PICKS)
+				warning(_("skipped previously applied commit %s"),
+					short_commit_name(commit));
+			skipped_commit = 1;
 			continue;
+		}
 		if (is_empty && !keep_empty)
 			continue;
 
@@ -5225,6 +5255,9 @@
 		oidcpy(&entry->entry.oid, &commit->object.oid);
 		oidmap_put(&commit2todo, entry);
 	}
+	if (skipped_commit)
+		advise_if_enabled(ADVICE_SKIPPED_CHERRY_PICKS,
+				  _("use --reapply-cherry-picks to include skipped commits"));
 
 	/*
 	 * Second phase:
@@ -5345,6 +5378,7 @@
 	const char *insn = flags & TODO_LIST_ABBREVIATE_CMDS ? "p" : "pick";
 	int rebase_merges = flags & TODO_LIST_REBASE_MERGES;
 	int reapply_cherry_picks = flags & TODO_LIST_REAPPLY_CHERRY_PICKS;
+	int skipped_commit = 0;
 
 	repo_init_revisions(r, &revs, NULL);
 	revs.verbose_header = 1;
@@ -5380,8 +5414,13 @@
 	while ((commit = get_revision(&revs))) {
 		int is_empty = is_original_commit_empty(commit);
 
-		if (!is_empty && (commit->object.flags & PATCHSAME))
+		if (!is_empty && (commit->object.flags & PATCHSAME)) {
+			if (flags & TODO_LIST_WARN_SKIPPED_CHERRY_PICKS)
+				warning(_("skipped previously applied commit %s"),
+					short_commit_name(commit));
+			skipped_commit = 1;
 			continue;
+		}
 		if (is_empty && !keep_empty)
 			continue;
 		strbuf_addf(out, "%s %s ", insn,
@@ -5391,6 +5430,9 @@
 			strbuf_addf(out, " %c empty", comment_line_char);
 		strbuf_addch(out, '\n');
 	}
+	if (skipped_commit)
+		advise_if_enabled(ADVICE_SKIPPED_CHERRY_PICKS,
+				  _("use --reapply-cherry-picks to include skipped commits"));
 	return 0;
 }
 
@@ -5398,8 +5440,8 @@
  * Add commands after pick and (series of) squash/fixup commands
  * in the todo list.
  */
-void todo_list_add_exec_commands(struct todo_list *todo_list,
-				 struct string_list *commands)
+static void todo_list_add_exec_commands(struct todo_list *todo_list,
+					struct string_list *commands)
 {
 	struct strbuf *buf = &todo_list->buf;
 	size_t base_offset = buf->len;
diff --git a/sequencer.h b/sequencer.h
index d57d8ea..05a7d2b 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -116,10 +116,11 @@
 	struct todo_item *items;
 	int nr, alloc, current;
 	int done_nr, total_nr;
-	struct stat_data stat;
 };
 
-#define TODO_LIST_INIT { STRBUF_INIT }
+#define TODO_LIST_INIT { \
+	.buf = STRBUF_INIT, \
+}
 
 int todo_list_parse_insn_buffer(struct repository *r, char *buf,
 				struct todo_list *todo_list);
@@ -156,12 +157,11 @@
  */
 #define TODO_LIST_ROOT_WITH_ONTO (1U << 6)
 #define TODO_LIST_REAPPLY_CHERRY_PICKS (1U << 7)
+#define TODO_LIST_WARN_SKIPPED_CHERRY_PICKS (1U << 8)
 
 int sequencer_make_script(struct repository *r, struct strbuf *out, int argc,
 			  const char **argv, unsigned flags);
 
-void todo_list_add_exec_commands(struct todo_list *todo_list,
-				 struct string_list *commands);
 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,
diff --git a/serve.c b/serve.c
index f11c0e0..b3fe9b5 100644
--- a/serve.c
+++ b/serve.c
@@ -9,7 +9,8 @@
 #include "serve.h"
 #include "upload-pack.h"
 
-static int advertise_sid;
+static int advertise_sid = -1;
+static int client_hash_algo = GIT_HASH_SHA1;
 
 static int always_advertise(struct repository *r,
 			    struct strbuf *value)
@@ -33,8 +34,22 @@
 	return 1;
 }
 
+static void object_format_receive(struct repository *r,
+				  const char *algo_name)
+{
+	if (!algo_name)
+		die("object-format capability requires an argument");
+
+	client_hash_algo = hash_algo_by_name(algo_name);
+	if (client_hash_algo == GIT_HASH_UNKNOWN)
+		die("unknown object format '%s'", algo_name);
+}
+
 static int session_id_advertise(struct repository *r, struct strbuf *value)
 {
+	if (advertise_sid == -1 &&
+	    git_config_get_bool("transfer.advertisesid", &advertise_sid))
+		advertise_sid = 0;
 	if (!advertise_sid)
 		return 0;
 	if (value)
@@ -42,6 +57,14 @@
 	return 1;
 }
 
+static void session_id_receive(struct repository *r,
+			       const char *client_sid)
+{
+	if (!client_sid)
+		client_sid = "";
+	trace2_data_string("transfer", NULL, "client-sid", client_sid);
+}
+
 struct protocol_capability {
 	/*
 	 * The name of the capability.  The server uses this name when
@@ -60,34 +83,70 @@
 
 	/*
 	 * Function called when a client requests the capability as a command.
-	 * The function will be provided the capabilities requested via 'keys'
-	 * as well as a struct packet_reader 'request' which the command should
+	 * Will be provided a struct packet_reader 'request' which it should
 	 * use to read the command specific part of the request.  Every command
 	 * MUST read until a flush packet is seen before sending a response.
 	 *
 	 * This field should be NULL for capabilities which are not commands.
 	 */
-	int (*command)(struct repository *r,
-		       struct strvec *keys,
-		       struct packet_reader *request);
+	int (*command)(struct repository *r, struct packet_reader *request);
+
+	/*
+	 * Function called when a client requests the capability as a
+	 * non-command. This may be NULL if the capability does nothing.
+	 *
+	 * For a capability of the form "foo=bar", the value string points to
+	 * the content after the "=" (i.e., "bar"). For simple capabilities
+	 * (just "foo"), it is NULL.
+	 */
+	void (*receive)(struct repository *r, const char *value);
 };
 
 static struct protocol_capability capabilities[] = {
-	{ "agent", agent_advertise, NULL },
-	{ "ls-refs", ls_refs_advertise, ls_refs },
-	{ "fetch", upload_pack_advertise, upload_pack_v2 },
-	{ "server-option", always_advertise, NULL },
-	{ "object-format", object_format_advertise, NULL },
-	{ "session-id", session_id_advertise, NULL },
-	{ "object-info", always_advertise, cap_object_info },
+	{
+		.name = "agent",
+		.advertise = agent_advertise,
+	},
+	{
+		.name = "ls-refs",
+		.advertise = ls_refs_advertise,
+		.command = ls_refs,
+	},
+	{
+		.name = "fetch",
+		.advertise = upload_pack_advertise,
+		.command = upload_pack_v2,
+	},
+	{
+		.name = "server-option",
+		.advertise = always_advertise,
+	},
+	{
+		.name = "object-format",
+		.advertise = object_format_advertise,
+		.receive = object_format_receive,
+	},
+	{
+		.name = "session-id",
+		.advertise = session_id_advertise,
+		.receive = session_id_receive,
+	},
+	{
+		.name = "object-info",
+		.advertise = always_advertise,
+		.command = cap_object_info,
+	},
 };
 
-static void advertise_capabilities(void)
+void protocol_v2_advertise_capabilities(void)
 {
 	struct strbuf capability = STRBUF_INIT;
 	struct strbuf value = STRBUF_INIT;
 	int i;
 
+	/* serve by default supports v2 */
+	packet_write_fmt(1, "version 2\n");
+
 	for (i = 0; i < ARRAY_SIZE(capabilities); i++) {
 		struct protocol_capability *c = &capabilities[i];
 
@@ -112,7 +171,7 @@
 	strbuf_release(&value);
 }
 
-static struct protocol_capability *get_capability(const char *key)
+static struct protocol_capability *get_capability(const char *key, const char **value)
 {
 	int i;
 
@@ -122,31 +181,46 @@
 	for (i = 0; i < ARRAY_SIZE(capabilities); i++) {
 		struct protocol_capability *c = &capabilities[i];
 		const char *out;
-		if (skip_prefix(key, c->name, &out) && (!*out || *out == '='))
+		if (!skip_prefix(key, c->name, &out))
+			continue;
+		if (!*out) {
+			*value = NULL;
 			return c;
+		}
+		if (*out++ == '=') {
+			*value = out;
+			return c;
+		}
 	}
 
 	return NULL;
 }
 
-static int is_valid_capability(const char *key)
+static int receive_client_capability(const char *key)
 {
-	const struct protocol_capability *c = get_capability(key);
+	const char *value;
+	const struct protocol_capability *c = get_capability(key, &value);
 
-	return c && c->advertise(the_repository, NULL);
+	if (!c || c->command || !c->advertise(the_repository, NULL))
+		return 0;
+
+	if (c->receive)
+		c->receive(the_repository, value);
+	return 1;
 }
 
-static int is_command(const char *key, struct protocol_capability **command)
+static int parse_command(const char *key, struct protocol_capability **command)
 {
 	const char *out;
 
 	if (skip_prefix(key, "command=", &out)) {
-		struct protocol_capability *cmd = get_capability(out);
+		const char *value;
+		struct protocol_capability *cmd = get_capability(out, &value);
 
 		if (*command)
 			die("command '%s' requested after already requesting command '%s'",
 			    out, (*command)->name);
-		if (!cmd || !cmd->advertise(the_repository, NULL) || !cmd->command)
+		if (!cmd || !cmd->advertise(the_repository, NULL) || !cmd->command || value)
 			die("invalid command '%s'", out);
 
 		*command = cmd;
@@ -156,42 +230,6 @@
 	return 0;
 }
 
-int has_capability(const struct strvec *keys, const char *capability,
-		   const char **value)
-{
-	int i;
-	for (i = 0; i < keys->nr; i++) {
-		const char *out;
-		if (skip_prefix(keys->v[i], capability, &out) &&
-		    (!*out || *out == '=')) {
-			if (value) {
-				if (*out == '=')
-					out++;
-				*value = out;
-			}
-			return 1;
-		}
-	}
-
-	return 0;
-}
-
-static void check_algorithm(struct repository *r, struct strvec *keys)
-{
-	int client = GIT_HASH_SHA1, server = hash_algo_by_ptr(r->hash_algo);
-	const char *algo_name;
-
-	if (has_capability(keys, "object-format", &algo_name)) {
-		client = hash_algo_by_name(algo_name);
-		if (client == GIT_HASH_UNKNOWN)
-			die("unknown object format '%s'", algo_name);
-	}
-
-	if (client != server)
-		die("mismatched object format: server %s; client %s\n",
-		    r->hash_algo->name, hash_algos[client].name);
-}
-
 enum request_state {
 	PROCESS_REQUEST_KEYS,
 	PROCESS_REQUEST_DONE,
@@ -201,9 +239,8 @@
 {
 	enum request_state state = PROCESS_REQUEST_KEYS;
 	struct packet_reader reader;
-	struct strvec keys = STRVEC_INIT;
+	int seen_capability_or_command = 0;
 	struct protocol_capability *command = NULL;
-	const char *client_sid;
 
 	packet_reader_init(&reader, 0, NULL, 0,
 			   PACKET_READ_CHOMP_NEWLINE |
@@ -223,10 +260,9 @@
 		case PACKET_READ_EOF:
 			BUG("Should have already died when seeing EOF");
 		case PACKET_READ_NORMAL:
-			/* collect request; a sequence of keys and values */
-			if (is_command(reader.line, &command) ||
-			    is_valid_capability(reader.line))
-				strvec_push(&keys, reader.line);
+			if (parse_command(reader.line, &command) ||
+			    receive_client_capability(reader.line))
+				seen_capability_or_command = 1;
 			else
 				die("unknown capability '%s'", reader.line);
 
@@ -238,7 +274,7 @@
 			 * If no command and no keys were given then the client
 			 * wanted to terminate the connection.
 			 */
-			if (!keys.nr)
+			if (!seen_capability_or_command)
 				return 1;
 
 			/*
@@ -265,40 +301,26 @@
 	if (!command)
 		die("no command requested");
 
-	check_algorithm(the_repository, &keys);
+	if (client_hash_algo != hash_algo_by_ptr(the_repository->hash_algo))
+		die("mismatched object format: server %s; client %s\n",
+		    the_repository->hash_algo->name,
+		    hash_algos[client_hash_algo].name);
 
-	if (has_capability(&keys, "session-id", &client_sid))
-		trace2_data_string("transfer", NULL, "client-sid", client_sid);
+	command->command(the_repository, &reader);
 
-	command->command(the_repository, &keys, &reader);
-
-	strvec_clear(&keys);
 	return 0;
 }
 
-/* Main serve loop for protocol version 2 */
-void serve(struct serve_options *options)
+void protocol_v2_serve_loop(int stateless_rpc)
 {
-	git_config_get_bool("transfer.advertisesid", &advertise_sid);
-
-	if (options->advertise_capabilities || !options->stateless_rpc) {
-		/* serve by default supports v2 */
-		packet_write_fmt(1, "version 2\n");
-
-		advertise_capabilities();
-		/*
-		 * If only the list of capabilities was requested exit
-		 * immediately after advertising capabilities
-		 */
-		if (options->advertise_capabilities)
-			return;
-	}
+	if (!stateless_rpc)
+		protocol_v2_advertise_capabilities();
 
 	/*
 	 * If stateless-rpc was requested then exit after
 	 * a single request/response exchange
 	 */
-	if (options->stateless_rpc) {
+	if (stateless_rpc) {
 		process_request();
 	} else {
 		for (;;)
diff --git a/serve.h b/serve.h
index fc2683e..f946cf9 100644
--- a/serve.h
+++ b/serve.h
@@ -1,15 +1,7 @@
 #ifndef SERVE_H
 #define SERVE_H
 
-struct strvec;
-int has_capability(const struct strvec *keys, const char *capability,
-		   const char **value);
-
-struct serve_options {
-	unsigned advertise_capabilities;
-	unsigned stateless_rpc;
-};
-#define SERVE_OPTIONS_INIT { 0 }
-void serve(struct serve_options *options);
+void protocol_v2_advertise_capabilities(void);
+void protocol_v2_serve_loop(int stateless_rpc);
 
 #endif /* SERVE_H */
diff --git a/shallow.h b/shallow.h
index 5b4a96d..aba6ff5 100644
--- a/shallow.h
+++ b/shallow.h
@@ -23,7 +23,9 @@
 struct shallow_lock {
 	struct lock_file lock;
 };
-#define SHALLOW_LOCK_INIT { LOCK_INIT }
+#define SHALLOW_LOCK_INIT { \
+	.lock = LOCK_INIT, \
+}
 
 /* commit $GIT_DIR/shallow and reset stat-validity checks */
 int commit_shallow_file(struct repository *r, struct shallow_lock *lk);
diff --git a/simple-ipc.h b/simple-ipc.h
index 2c48a5e..a849d9f 100644
--- a/simple-ipc.h
+++ b/simple-ipc.h
@@ -5,13 +5,6 @@
  * See Documentation/technical/api-simple-ipc.txt
  */
 
-#ifdef SUPPORTS_SIMPLE_IPC
-#include "pkt-line.h"
-
-/*
- * Simple IPC Client Side API.
- */
-
 enum ipc_active_state {
 	/*
 	 * The pipe/socket exists and the daemon is waiting for connections.
@@ -43,6 +36,13 @@
 	IPC_STATE__OTHER_ERROR,
 };
 
+#ifdef SUPPORTS_SIMPLE_IPC
+#include "pkt-line.h"
+
+/*
+ * Simple IPC Client Side API.
+ */
+
 struct ipc_client_connect_options {
 	/*
 	 * Spin under timeout if the server is running but can't
@@ -65,11 +65,7 @@
 	unsigned int uds_disallow_chdir:1;
 };
 
-#define IPC_CLIENT_CONNECT_OPTIONS_INIT { \
-	.wait_if_busy = 0, \
-	.wait_if_not_found = 0, \
-	.uds_disallow_chdir = 0, \
-}
+#define IPC_CLIENT_CONNECT_OPTIONS_INIT { 0 }
 
 /*
  * Determine if a server is listening on this named pipe or socket using
@@ -107,7 +103,8 @@
  */
 int ipc_client_send_command_to_connection(
 	struct ipc_client_connection *connection,
-	const char *message, struct strbuf *answer);
+	const char *message, size_t message_len,
+	struct strbuf *answer);
 
 /*
  * Used by the client to synchronously connect and send and receive a
@@ -119,7 +116,8 @@
  */
 int ipc_client_send_command(const char *path,
 			    const struct ipc_client_connect_options *options,
-			    const char *message, struct strbuf *answer);
+			    const char *message, size_t message_len,
+			    struct strbuf *answer);
 
 /*
  * Simple IPC Server Side API.
@@ -144,6 +142,7 @@
  */
 typedef int (ipc_server_application_cb)(void *application_data,
 					const char *request,
+					size_t request_len,
 					ipc_server_reply_cb *reply_cb,
 					struct ipc_server_reply_data *reply_data);
 
diff --git a/sparse-index.c b/sparse-index.c
index 56eb65d..7b7ff79 100644
--- a/sparse-index.c
+++ b/sparse-index.c
@@ -33,19 +33,14 @@
 {
 	int i, can_convert = 1;
 	int start_converted = num_converted;
-	enum pattern_match_result match;
-	int dtype = DT_UNKNOWN;
 	struct strbuf child_path = STRBUF_INIT;
-	struct pattern_list *pl = istate->sparse_checkout_patterns;
 
 	/*
 	 * Is the current path outside of the sparse cone?
 	 * Then check if the region can be replaced by a sparse
 	 * directory entry (everything is sparse and merged).
 	 */
-	match = path_matches_pattern_list(ct_path, ct_pathlen,
-					  NULL, &dtype, pl, istate);
-	if (match != NOT_MATCHED)
+	if (path_in_sparse_checkout(ct_path, istate))
 		can_convert = 0;
 
 	for (i = start; can_convert && i < end; i++) {
@@ -127,41 +122,51 @@
 	return 0;
 }
 
-int convert_to_sparse(struct index_state *istate)
+int convert_to_sparse(struct index_state *istate, int flags)
 {
 	int test_env;
-	if (istate->split_index || istate->sparse_index ||
+	if (istate->sparse_index || !istate->cache_nr ||
 	    !core_apply_sparse_checkout || !core_sparse_checkout_cone)
 		return 0;
 
 	if (!istate->repo)
 		istate->repo = the_repository;
 
-	/*
-	 * The GIT_TEST_SPARSE_INDEX environment variable triggers the
-	 * index.sparse config variable to be on.
-	 */
-	test_env = git_env_bool("GIT_TEST_SPARSE_INDEX", -1);
-	if (test_env >= 0)
-		set_sparse_index_config(istate->repo, test_env);
+	if (!(flags & SPARSE_INDEX_MEMORY_ONLY)) {
+		/*
+		 * The sparse index is not (yet) integrated with a split index.
+		 */
+		if (istate->split_index)
+			return 0;
+		/*
+		 * The GIT_TEST_SPARSE_INDEX environment variable triggers the
+		 * index.sparse config variable to be on.
+		 */
+		test_env = git_env_bool("GIT_TEST_SPARSE_INDEX", -1);
+		if (test_env >= 0)
+			set_sparse_index_config(istate->repo, test_env);
 
-	/*
-	 * Only convert to sparse if index.sparse is set.
-	 */
-	prepare_repo_settings(istate->repo);
-	if (!istate->repo->settings.sparse_index)
-		return 0;
-
-	if (!istate->sparse_checkout_patterns) {
-		istate->sparse_checkout_patterns = xcalloc(1, sizeof(struct pattern_list));
-		if (get_sparse_checkout_patterns(istate->sparse_checkout_patterns) < 0)
+		/*
+		 * Only convert to sparse if index.sparse is set.
+		 */
+		prepare_repo_settings(istate->repo);
+		if (!istate->repo->settings.sparse_index)
 			return 0;
 	}
 
-	if (!istate->sparse_checkout_patterns->use_cone_patterns) {
-		warning(_("attempting to use sparse-index without cone mode"));
-		return -1;
-	}
+	if (init_sparse_checkout_patterns(istate))
+		return 0;
+
+	/*
+	 * We need cone-mode patterns to use sparse-index. If a user edits
+	 * their sparse-checkout file manually, then we can detect during
+	 * parsing that they are not actually using cone-mode patterns and
+	 * hence we need to abort this conversion _without error_. Warnings
+	 * already exist in the pattern parsing to inform the user of their
+	 * bad patterns.
+	 */
+	if (!istate->sparse_checkout_patterns->use_cone_patterns)
+		return 0;
 
 	/*
 	 * NEEDSWORK: If we have unmerged entries, then stay full.
@@ -172,10 +177,15 @@
 
 	/* Clear and recompute the cache-tree */
 	cache_tree_free(&istate->cache_tree);
-	if (cache_tree_update(istate, 0)) {
-		warning(_("unable to update cache-tree, staying full"));
-		return -1;
-	}
+	/*
+	 * Silently return if there is a problem with the cache tree update,
+	 * which might just be due to a conflict state in some entry.
+	 *
+	 * This might create new tree objects, so be sure to use
+	 * WRITE_TREE_MISSING_OK.
+	 */
+	if (cache_tree_update(istate, WRITE_TREE_MISSING_OK))
+		return 0;
 
 	remove_fsmonitor(istate);
 
diff --git a/sparse-index.h b/sparse-index.h
index 1115a0d..9f3d7bc 100644
--- a/sparse-index.h
+++ b/sparse-index.h
@@ -2,7 +2,8 @@
 #define SPARSE_INDEX_H__
 
 struct index_state;
-int convert_to_sparse(struct index_state *istate);
+#define SPARSE_INDEX_MEMORY_ONLY (1 << 0)
+int convert_to_sparse(struct index_state *istate, int flags);
 
 /*
  * Some places in the codebase expect to search for a specific path.
diff --git a/strbuf.c b/strbuf.c
index c8a5789..b22e981 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -1059,15 +1059,21 @@
 	strbuf_setlen(sb, sb->len + len);
 }
 
-void strbuf_add_unique_abbrev(struct strbuf *sb, const struct object_id *oid,
-			      int abbrev_len)
+void strbuf_repo_add_unique_abbrev(struct strbuf *sb, struct repository *repo,
+				   const struct object_id *oid, int abbrev_len)
 {
 	int r;
 	strbuf_grow(sb, GIT_MAX_HEXSZ + 1);
-	r = find_unique_abbrev_r(sb->buf + sb->len, oid, abbrev_len);
+	r = repo_find_unique_abbrev_r(repo, sb->buf + sb->len, oid, abbrev_len);
 	strbuf_setlen(sb, sb->len + r);
 }
 
+void strbuf_add_unique_abbrev(struct strbuf *sb, const struct object_id *oid,
+			      int abbrev_len)
+{
+	strbuf_repo_add_unique_abbrev(sb, the_repository, oid, abbrev_len);
+}
+
 /*
  * Returns the length of a line, without trailing spaces.
  *
diff --git a/strbuf.h b/strbuf.h
index 5b1113a..96512f8 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -70,7 +70,7 @@
 };
 
 extern char strbuf_slopbuf[];
-#define STRBUF_INIT  { .alloc = 0, .len = 0, .buf = strbuf_slopbuf }
+#define STRBUF_INIT  { .buf = strbuf_slopbuf }
 
 /*
  * Predeclare this here, since cache.h includes this file before it defines the
@@ -634,8 +634,10 @@
  * Add the abbreviation, as generated by find_unique_abbrev, of `sha1` to
  * the strbuf `sb`.
  */
-void strbuf_add_unique_abbrev(struct strbuf *sb,
-			      const struct object_id *oid,
+struct repository;
+void strbuf_repo_add_unique_abbrev(struct strbuf *sb, struct repository *repo,
+				   const struct object_id *oid, int abbrev_len);
+void strbuf_add_unique_abbrev(struct strbuf *sb, const struct object_id *oid,
 			      int abbrev_len);
 
 /**
diff --git a/streaming.c b/streaming.c
index 5f480ad..fe54665 100644
--- a/streaming.c
+++ b/streaming.c
@@ -223,19 +223,24 @@
 			      const struct object_id *oid,
 			      enum object_type *type)
 {
+	struct object_info oi = OBJECT_INFO_INIT;
+	oi.sizep = &st->size;
+	oi.typep = type;
+
 	st->u.loose.mapped = map_loose_object(r, oid, &st->u.loose.mapsize);
 	if (!st->u.loose.mapped)
 		return -1;
-	if ((unpack_loose_header(&st->z,
-				 st->u.loose.mapped,
-				 st->u.loose.mapsize,
-				 st->u.loose.hdr,
-				 sizeof(st->u.loose.hdr)) < 0) ||
-	    (parse_loose_header(st->u.loose.hdr, &st->size) < 0)) {
-		git_inflate_end(&st->z);
-		munmap(st->u.loose.mapped, st->u.loose.mapsize);
-		return -1;
+	switch (unpack_loose_header(&st->z, st->u.loose.mapped,
+				    st->u.loose.mapsize, st->u.loose.hdr,
+				    sizeof(st->u.loose.hdr), NULL)) {
+	case ULHR_OK:
+		break;
+	case ULHR_BAD:
+	case ULHR_TOO_LONG:
+		goto error;
 	}
+	if (parse_loose_header(st->u.loose.hdr, &oi) < 0 || *type < 0)
+		goto error;
 
 	st->u.loose.hdr_used = strlen(st->u.loose.hdr) + 1;
 	st->u.loose.hdr_avail = st->z.total_out;
@@ -244,6 +249,10 @@
 	st->read = read_istream_loose;
 
 	return 0;
+error:
+	git_inflate_end(&st->z);
+	munmap(st->u.loose.mapped, st->u.loose.mapsize);
+	return -1;
 }
 
 
diff --git a/string-list.c b/string-list.c
index 43576ad..549fc41 100644
--- a/string-list.c
+++ b/string-list.c
@@ -13,14 +13,6 @@
 	memcpy(list, &blank, sizeof(*list));
 }
 
-void string_list_init(struct string_list *list, int strdup_strings)
-{
-	if (strdup_strings)
-		string_list_init_dup(list);
-	else
-		string_list_init_nodup(list);
-}
-
 /* if there is no exact match, point to the index where the entry could be
  * inserted */
 static int get_entry_index(const struct string_list *list, const char *string,
diff --git a/string-list.h b/string-list.h
index 0d6b469..267d6e5 100644
--- a/string-list.h
+++ b/string-list.h
@@ -104,11 +104,6 @@
 void string_list_init_nodup(struct string_list *list);
 void string_list_init_dup(struct string_list *list);
 
-/**
- * TODO remove: For compatibility with any in-flight older API users
- */
-void string_list_init(struct string_list *list, int strdup_strings);
-
 /** Callback function type for for_each_string_list */
 typedef int (*string_list_each_func_t)(struct string_list_item *, void *);
 
diff --git a/strvec.h b/strvec.h
index 6b3cbd6..9f55c87 100644
--- a/strvec.h
+++ b/strvec.h
@@ -33,7 +33,9 @@
 	size_t alloc;
 };
 
-#define STRVEC_INIT { empty_strvec, 0, 0 }
+#define STRVEC_INIT { \
+	.v = empty_strvec, \
+}
 
 /**
  * Initialize an array. This is no different than assigning from
diff --git a/submodule-config.c b/submodule-config.c
index 2026120..f953440 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -649,9 +649,10 @@
 			config_source.file = file;
 		} else if (repo_get_oid(repo, GITMODULES_INDEX, &oid) >= 0 ||
 			   repo_get_oid(repo, GITMODULES_HEAD, &oid) >= 0) {
+			config_source.repo = repo;
 			config_source.blob = oidstr = xstrdup(oid_to_hex(&oid));
 			if (repo != the_repository)
-				add_to_alternates_memory(repo->objects->odb->path);
+				add_submodule_odb_by_path(repo->objects->odb->path);
 		} else {
 			goto out;
 		}
@@ -702,7 +703,7 @@
 
 	if (gitmodule_oid_from_commit(commit_oid, &oid, &rev)) {
 		git_config_from_blob_oid(gitmodules_cb, rev.buf,
-					 &oid, the_repository);
+					 the_repository, &oid, the_repository);
 	}
 	strbuf_release(&rev);
 
diff --git a/submodule-config.h b/submodule-config.h
index c11e22c..65875b9 100644
--- a/submodule-config.h
+++ b/submodule-config.h
@@ -45,10 +45,6 @@
 	struct object_id gitmodules_oid;
 	int recommend_shallow;
 };
-
-#define SUBMODULE_INIT { NULL, NULL, NULL, RECURSE_SUBMODULES_NONE, \
-	NULL, NULL, SUBMODULE_UPDATE_STRATEGY_INIT, { { 0 } }, -1 };
-
 struct submodule_cache;
 struct repository;
 
diff --git a/submodule.c b/submodule.c
index 8e611fe..c689070 100644
--- a/submodule.c
+++ b/submodule.c
@@ -165,6 +165,8 @@
 		die(_("staging updated .gitmodules failed"));
 }
 
+static struct string_list added_submodule_odb_paths = STRING_LIST_INIT_NODUP;
+
 /* TODO: remove this function, use repo_submodule_init instead. */
 int add_submodule_odb(const char *path)
 {
@@ -178,12 +180,35 @@
 		ret = -1;
 		goto done;
 	}
-	add_to_alternates_memory(objects_directory.buf);
+	string_list_insert(&added_submodule_odb_paths,
+			   strbuf_detach(&objects_directory, NULL));
 done:
 	strbuf_release(&objects_directory);
 	return ret;
 }
 
+void add_submodule_odb_by_path(const char *path)
+{
+	string_list_insert(&added_submodule_odb_paths, xstrdup(path));
+}
+
+int register_all_submodule_odb_as_alternates(void)
+{
+	int i;
+	int ret = added_submodule_odb_paths.nr;
+
+	for (i = 0; i < added_submodule_odb_paths.nr; i++)
+		add_to_alternates_memory(added_submodule_odb_paths.items[i].string);
+	if (ret) {
+		string_list_clear(&added_submodule_odb_paths, 0);
+		trace2_data_intmax("submodule", the_repository,
+				   "register_all_submodule_odb_as_alternates/registered", ret);
+		if (git_env_bool("GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB", 0))
+			BUG("register_all_submodule_odb_as_alternates() called");
+	}
+	return ret;
+}
+
 void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 					     const char *path)
 {
@@ -237,6 +262,11 @@
 /*
  * Determine if a submodule has been initialized at a given 'path'
  */
+/*
+ * NEEDSWORK: Emit a warning if submodule.active exists, but is valueless,
+ * ie, the config looks like: "[submodule] active\n".
+ * Since that is an invalid pathspec, we should inform the user.
+ */
 int is_submodule_active(struct repository *repo, const char *path)
 {
 	int ret = 0;
@@ -497,9 +527,6 @@
 /*
  * Initialize a repository struct for a submodule based on the provided 'path'.
  *
- * Unlike repo_submodule_init, this tolerates submodules not present
- * in .gitmodules. This function exists only to preserve historical behavior,
- *
  * Returns the repository struct on success,
  * NULL when the submodule is not present.
  */
@@ -697,8 +724,20 @@
 		strvec_push(&cp.args, oid_to_hex(new_oid));
 
 	prepare_submodule_repo_env(&cp.env_array);
-	if (start_command(&cp))
+
+	if (!is_directory(path)) {
+		/* fall back to absorbed git dir, if any */
+		if (!sub)
+			goto done;
+		cp.dir = sub->gitdir;
+		strvec_push(&cp.env_array, GIT_DIR_ENVIRONMENT "=.");
+		strvec_push(&cp.env_array, GIT_WORK_TREE_ENVIRONMENT "=.");
+	}
+
+	if (start_command(&cp)) {
 		diff_emit_submodule_error(o, "(diff failed)\n");
+		goto done;
+	}
 
 	while (strbuf_getwholeline_fd(&sb, cp.out, '\n') != EOF)
 		diff_emit_submodule_pipethrough(o, sb.buf, sb.len);
@@ -891,23 +930,33 @@
 static int check_has_commit(const struct object_id *oid, void *data)
 {
 	struct has_commit_data *cb = data;
+	struct repository subrepo;
+	enum object_type type;
 
-	enum object_type type = oid_object_info(cb->repo, oid, NULL);
+	if (repo_submodule_init(&subrepo, cb->repo, cb->path, null_oid())) {
+		cb->result = 0;
+		goto cleanup;
+	}
+
+	type = oid_object_info(&subrepo, oid, NULL);
 
 	switch (type) {
 	case OBJ_COMMIT:
-		return 0;
+		goto cleanup;
 	case OBJ_BAD:
 		/*
 		 * Object is missing or invalid. If invalid, an error message
 		 * has already been printed.
 		 */
 		cb->result = 0;
-		return 0;
+		goto cleanup;
 	default:
 		die(_("submodule entry '%s' (%s) is a %s, not a commit"),
 		    cb->path, oid_to_hex(oid), type_name(type));
 	}
+cleanup:
+	repo_clear(&subrepo);
+	return 0;
 }
 
 static int submodule_has_commits(struct repository *r,
@@ -1281,9 +1330,11 @@
 
 	struct strbuf submodules_with_errors;
 };
-#define SPF_INIT {0, STRVEC_INIT, NULL, NULL, 0, 0, 0, 0, \
-		  STRING_LIST_INIT_DUP, \
-		  NULL, 0, 0, STRBUF_INIT}
+#define SPF_INIT { \
+	.args = STRVEC_INIT, \
+	.changed_submodule_names = STRING_LIST_INIT_DUP, \
+	.submodules_with_errors = STRBUF_INIT, \
+}
 
 static int get_fetch_recurse_config(const struct submodule *submodule,
 				    struct submodule_parallel_fetch *spf)
@@ -1381,24 +1432,13 @@
 }
 
 static struct repository *get_submodule_repo_for(struct repository *r,
-						 const struct submodule *sub)
+						 const char *path)
 {
 	struct repository *ret = xmalloc(sizeof(*ret));
 
-	if (repo_submodule_init(ret, r, sub)) {
-		/*
-		 * No entry in .gitmodules? Technically not a submodule,
-		 * but historically we supported repositories that happen to be
-		 * in-place where a gitlink is. Keep supporting them.
-		 */
-		struct strbuf gitdir = STRBUF_INIT;
-		strbuf_repo_worktree_path(&gitdir, r, "%s/.git", sub->path);
-		if (repo_init(ret, gitdir.buf, NULL)) {
-			strbuf_release(&gitdir);
-			free(ret);
-			return NULL;
-		}
-		strbuf_release(&gitdir);
+	if (repo_submodule_init(ret, r, path, null_oid())) {
+		free(ret);
+		return NULL;
 	}
 
 	return ret;
@@ -1440,7 +1480,7 @@
 			continue;
 		}
 
-		task->repo = get_submodule_repo_for(spf->r, task->sub);
+		task->repo = get_submodule_repo_for(spf->r, task->sub->path);
 		if (task->repo) {
 			struct strbuf submodule_prefix = STRBUF_INIT;
 			child_process_init(cp);
@@ -1819,14 +1859,16 @@
 
 void submodule_unset_core_worktree(const struct submodule *sub)
 {
-	char *config_path = xstrfmt("%s/modules/%s/config",
-				    get_git_dir(), sub->name);
+	struct strbuf config_path = STRBUF_INIT;
 
-	if (git_config_set_in_file_gently(config_path, "core.worktree", NULL))
+	submodule_name_to_gitdir(&config_path, the_repository, sub->name);
+	strbuf_addstr(&config_path, "/config");
+
+	if (git_config_set_in_file_gently(config_path.buf, "core.worktree", NULL))
 		warning(_("Could not unset core.worktree setting in submodule '%s'"),
 			  sub->path);
 
-	free(config_path);
+	strbuf_release(&config_path);
 }
 
 static const char *get_super_prefix_or_empty(void)
@@ -1866,6 +1908,7 @@
 
 	strvec_pushf(&cp.args, "--super-prefix=%s%s/",
 		     get_super_prefix_or_empty(), path);
+	/* TODO: determine if this might overwright untracked files */
 	strvec_pushl(&cp.args, "read-tree", "-u", "--reset", NULL);
 
 	strvec_push(&cp.args, empty_tree_oid_hex());
@@ -1922,20 +1965,22 @@
 				absorb_git_dir_into_superproject(path,
 					ABSORB_GITDIR_RECURSE_SUBMODULES);
 		} else {
-			char *gitdir = xstrfmt("%s/modules/%s",
-				    get_git_dir(), sub->name);
-			connect_work_tree_and_git_dir(path, gitdir, 0);
-			free(gitdir);
+			struct strbuf gitdir = STRBUF_INIT;
+			submodule_name_to_gitdir(&gitdir, the_repository,
+						 sub->name);
+			connect_work_tree_and_git_dir(path, gitdir.buf, 0);
+			strbuf_release(&gitdir);
 
 			/* make sure the index is clean as well */
 			submodule_reset_index(path);
 		}
 
 		if (old_head && (flags & SUBMODULE_MOVE_HEAD_FORCE)) {
-			char *gitdir = xstrfmt("%s/modules/%s",
-				    get_git_dir(), sub->name);
-			connect_work_tree_and_git_dir(path, gitdir, 1);
-			free(gitdir);
+			struct strbuf gitdir = STRBUF_INIT;
+			submodule_name_to_gitdir(&gitdir, the_repository,
+						 sub->name);
+			connect_work_tree_and_git_dir(path, gitdir.buf, 1);
+			strbuf_release(&gitdir);
 		}
 	}
 
@@ -2050,7 +2095,7 @@
 static void relocate_single_git_dir_into_superproject(const char *path)
 {
 	char *old_git_dir = NULL, *real_old_git_dir = NULL, *real_new_git_dir = NULL;
-	char *new_git_dir;
+	struct strbuf new_gitdir = STRBUF_INIT;
 	const struct submodule *sub;
 
 	if (submodule_uses_worktrees(path))
@@ -2068,14 +2113,13 @@
 	if (!sub)
 		die(_("could not lookup name for submodule '%s'"), path);
 
-	new_git_dir = git_pathdup("modules/%s", sub->name);
-	if (validate_submodule_git_dir(new_git_dir, sub->name) < 0)
+	submodule_name_to_gitdir(&new_gitdir, the_repository, sub->name);
+	if (validate_submodule_git_dir(new_gitdir.buf, sub->name) < 0)
 		die(_("refusing to move '%s' into an existing git dir"),
 		    real_old_git_dir);
-	if (safe_create_leading_directories_const(new_git_dir) < 0)
-		die(_("could not create directory '%s'"), new_git_dir);
-	real_new_git_dir = real_pathdup(new_git_dir, 1);
-	free(new_git_dir);
+	if (safe_create_leading_directories_const(new_gitdir.buf) < 0)
+		die(_("could not create directory '%s'"), new_gitdir.buf);
+	real_new_git_dir = real_pathdup(new_gitdir.buf, 1);
 
 	fprintf(stderr, _("Migrating git directory of '%s%s' from\n'%s' to\n'%s'\n"),
 		get_super_prefix_or_empty(), path,
@@ -2086,6 +2130,7 @@
 	free(old_git_dir);
 	free(real_old_git_dir);
 	free(real_new_git_dir);
+	strbuf_release(&new_gitdir);
 }
 
 /*
@@ -2105,6 +2150,7 @@
 	/* Not populated? */
 	if (!sub_git_dir) {
 		const struct submodule *sub;
+		struct strbuf sub_gitdir = STRBUF_INIT;
 
 		if (err_code == READ_GITFILE_ERR_STAT_FAILED) {
 			/* unpopulated as expected */
@@ -2126,8 +2172,9 @@
 		sub = submodule_from_path(the_repository, null_oid(), path);
 		if (!sub)
 			die(_("could not lookup name for submodule '%s'"), path);
-		connect_work_tree_and_git_dir(path,
-			git_path("modules/%s", sub->name), 0);
+		submodule_name_to_gitdir(&sub_gitdir, the_repository, sub->name);
+		connect_work_tree_and_git_dir(path, sub_gitdir.buf, 0);
+		strbuf_release(&sub_gitdir);
 	} else {
 		/* Is it already absorbed into the superprojects git dir? */
 		char *real_sub_git_dir = real_pathdup(sub_git_dir, 1);
@@ -2278,9 +2325,36 @@
 			goto cleanup;
 		}
 		strbuf_reset(buf);
-		strbuf_git_path(buf, "%s/%s", "modules", sub->name);
+		submodule_name_to_gitdir(buf, the_repository, sub->name);
 	}
 
 cleanup:
 	return ret;
 }
+
+void submodule_name_to_gitdir(struct strbuf *buf, struct repository *r,
+			      const char *submodule_name)
+{
+	/*
+	 * NEEDSWORK: The current way of mapping a submodule's name to
+	 * its location in .git/modules/ has problems with some naming
+	 * schemes. For example, if a submodule is named "foo" and
+	 * another is named "foo/bar" (whether present in the same
+	 * superproject commit or not - the problem will arise if both
+	 * superproject commits have been checked out at any point in
+	 * time), or if two submodule names only have different cases in
+	 * a case-insensitive filesystem.
+	 *
+	 * There are several solutions, including encoding the path in
+	 * some way, introducing a submodule.<name>.gitdir config in
+	 * .git/config (not .gitmodules) that allows overriding what the
+	 * gitdir of a submodule would be (and teach Git, upon noticing
+	 * a clash, to automatically determine a non-clashing name and
+	 * to write such a config), or introducing a
+	 * submodule.<name>.gitdir config in .gitmodules that repo
+	 * administrators can explicitly set. Nothing has been decided,
+	 * so for now, just append the name at the end of the path.
+	 */
+	strbuf_repo_git_path(buf, r, "modules/");
+	strbuf_addstr(buf, submodule_name);
+}
diff --git a/submodule.h b/submodule.h
index 84640c4..6bd2c99 100644
--- a/submodule.h
+++ b/submodule.h
@@ -37,7 +37,9 @@
 	enum submodule_update_type type;
 	const char *command;
 };
-#define SUBMODULE_UPDATE_STRATEGY_INIT {SM_UPDATE_UNSPECIFIED, NULL}
+#define SUBMODULE_UPDATE_STRATEGY_INIT { \
+	.type = SM_UPDATE_UNSPECIFIED, \
+}
 
 int is_gitmodules_unmerged(struct index_state *istate);
 int is_writing_gitmodules_ok(void);
@@ -97,7 +99,15 @@
 #define SUBMODULE_REMOVAL_IGNORE_IGNORED_UNTRACKED (1<<2)
 int bad_to_remove_submodule(const char *path, unsigned flags);
 
+/*
+ * Call add_submodule_odb() to add the submodule at the given path to a list.
+ * When register_all_submodule_odb_as_alternates() is called, the object stores
+ * of all submodules in that list will be added as alternates in
+ * the_repository.
+ */
 int add_submodule_odb(const char *path);
+void add_submodule_odb_by_path(const char *path);
+int register_all_submodule_odb_as_alternates(void);
 
 /*
  * Checks if there are submodule changes in a..b. If a is the null OID,
@@ -125,6 +135,13 @@
 int submodule_to_gitdir(struct strbuf *buf, const char *submodule);
 
 /*
+ * Given a submodule name, create a path to where the submodule's gitdir lives
+ * inside of the provided repository's 'modules' directory.
+ */
+void submodule_name_to_gitdir(struct strbuf *buf, struct repository *r,
+			      const char *submodule_name);
+
+/*
  * Make sure that no submodule's git dir is nested in a sibling submodule's.
  */
 int validate_submodule_git_dir(char *git_dir, const char *submodule_name);
diff --git a/t/.gitattributes b/t/.gitattributes
index dafa17c..9930e28 100644
--- a/t/.gitattributes
+++ b/t/.gitattributes
@@ -1,6 +1,5 @@
 t[0-9][0-9][0-9][0-9]/* -whitespace
 /chainlint/*.expect eol=lf
-/lib-diff/* eol=lf
 /t0110/url-* binary
 /t3206/* eol=lf
 /t3900/*.txt eol=lf
diff --git a/t/README b/t/README
index 9e70122..29f7235 100644
--- a/t/README
+++ b/t/README
@@ -366,6 +366,13 @@
 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_PROTOCOL_VERSION=<n>, when set, makes 'protocol.version'
 default to n.
 
@@ -425,6 +432,10 @@
 index to be written after every 'git repack' command, and overrides the
 'core.multiPackIndex' setting to true.
 
+GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=<boolean>, when true, sets the
+'--bitmap' option on all invocations of 'git multi-pack-index write',
+and ignores pack-objects' '--write-bitmap-index'.
+
 GIT_TEST_SIDEBAND_ALL=<boolean>, when true, overrides the
 'uploadpack.allowSidebandAll' setting to true, and when false, forces
 fetch-pack to not request sideband-all (even if the server advertises
@@ -448,6 +459,13 @@
 to <n> and 'checkout.thresholdForParallelism' to 0, forcing the
 execution of the parallel-checkout code.
 
+GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB=<boolean>, when true, makes
+registering submodule ODBs as alternates a fatal action. Support for
+this environment variable can be removed once the migration to
+explicitly providing repositories when accessing submodule objects is
+complete or needs to be abandoned for whatever reason (in which case the
+migrated codepaths still retain their performance benefits).
+
 Naming Tests
 ------------
 
@@ -753,7 +771,8 @@
 --------------------
 
 There are a handful helper functions defined in the test harness
-library for your script to use.
+library for your script to use. Some of them are listed below;
+see test-lib-functions.sh for the full list and their options.
 
  - test_expect_success [<prereq>] <message> <script>
 
@@ -799,10 +818,12 @@
    argument.  This is primarily meant for use during the
    development of a new test script.
 
- - debug <git-command>
+ - debug [options] <git-command>
 
    Run a git command inside a debugger. This is primarily meant for
-   use when debugging a failing test script.
+   use when debugging a failing test script. With '-t', use your
+   original TERM instead of test-lib.sh's "dumb", so that your
+   debugger interface has colors.
 
  - test_done
 
@@ -989,7 +1010,7 @@
 	EOF
 
 
- - test_pause
+ - test_pause [options]
 
 	This command is useful for writing and debugging tests and must be
 	removed before submitting. It halts the execution of the test and
diff --git a/t/helper/test-bitmap.c b/t/helper/test-bitmap.c
index 134a1e9..ff35f59 100644
--- a/t/helper/test-bitmap.c
+++ b/t/helper/test-bitmap.c
@@ -7,6 +7,11 @@
 	return test_bitmap_commits(the_repository);
 }
 
+static int bitmap_dump_hashes(void)
+{
+	return test_bitmap_hashes(the_repository);
+}
+
 int cmd__bitmap(int argc, const char **argv)
 {
 	setup_git_directory();
@@ -16,9 +21,12 @@
 
 	if (!strcmp(argv[1], "list-commits"))
 		return bitmap_list_commits();
+	if (!strcmp(argv[1], "dump-hashes"))
+		return bitmap_dump_hashes();
 
 usage:
-	usage("\ttest-tool bitmap list-commits");
+	usage("\ttest-tool bitmap list-commits\n"
+	      "\ttest-tool bitmap dump-hashes");
 
 	return -1;
 }
diff --git a/t/helper/test-dump-untracked-cache.c b/t/helper/test-dump-untracked-cache.c
index cf0f2c7..9901061 100644
--- a/t/helper/test-dump-untracked-cache.c
+++ b/t/helper/test-dump-untracked-cache.c
@@ -45,8 +45,10 @@
 	struct untracked_cache *uc;
 	struct strbuf base = STRBUF_INIT;
 
-	/* Hack to avoid modifying the untracked cache when we read it */
-	ignore_untracked_cache_config = 1;
+	/* Set core.untrackedCache=keep before setup_git_directory() */
+	xsetenv("GIT_CONFIG_COUNT", "1", 1);
+	xsetenv("GIT_CONFIG_KEY_0", "core.untrackedCache", 1);
+	xsetenv("GIT_CONFIG_VALUE_0", "keep", 1);
 
 	setup_git_directory();
 	if (read_cache() < 0)
diff --git a/t/helper/test-mergesort.c b/t/helper/test-mergesort.c
index c5cffaa..ebf68f7 100644
--- a/t/helper/test-mergesort.c
+++ b/t/helper/test-mergesort.c
@@ -2,6 +2,12 @@
 #include "cache.h"
 #include "mergesort.h"
 
+static uint32_t minstd_rand(uint32_t *state)
+{
+	*state = (uint64_t)*state * 48271 % 2147483647;
+	return *state;
+}
+
 struct line {
 	char *text;
 	struct line *next;
@@ -23,14 +29,12 @@
 	return strcmp(x->text, y->text);
 }
 
-int cmd__mergesort(int argc, const char **argv)
+static int sort_stdin(void)
 {
 	struct line *line, *p = NULL, *lines = NULL;
 	struct strbuf sb = STRBUF_INIT;
 
-	for (;;) {
-		if (strbuf_getwholeline(&sb, stdin, '\n'))
-			break;
+	while (!strbuf_getline(&sb, stdin)) {
 		line = xmalloc(sizeof(struct line));
 		line->text = strbuf_detach(&sb, NULL);
 		if (p) {
@@ -46,8 +50,362 @@
 	lines = llist_mergesort(lines, get_next, set_next, compare_strings);
 
 	while (lines) {
-		printf("%s", lines->text);
+		puts(lines->text);
 		lines = lines->next;
 	}
 	return 0;
 }
+
+static void dist_sawtooth(int *arr, int n, int m)
+{
+	int i;
+	for (i = 0; i < n; i++)
+		arr[i] = i % m;
+}
+
+static void dist_rand(int *arr, int n, int m)
+{
+	int i;
+	uint32_t seed = 1;
+	for (i = 0; i < n; i++)
+		arr[i] = minstd_rand(&seed) % m;
+}
+
+static void dist_stagger(int *arr, int n, int m)
+{
+	int i;
+	for (i = 0; i < n; i++)
+		arr[i] = (i * m + i) % n;
+}
+
+static void dist_plateau(int *arr, int n, int m)
+{
+	int i;
+	for (i = 0; i < n; i++)
+		arr[i] = (i < m) ? i : m;
+}
+
+static void dist_shuffle(int *arr, int n, int m)
+{
+	int i, j, k;
+	uint32_t seed = 1;
+	for (i = j = 0, k = 1; i < n; i++)
+		arr[i] = minstd_rand(&seed) % m ? (j += 2) : (k += 2);
+}
+
+#define DIST(name) { #name, dist_##name }
+
+static struct dist {
+	const char *name;
+	void (*fn)(int *arr, int n, int m);
+} dist[] = {
+	DIST(sawtooth),
+	DIST(rand),
+	DIST(stagger),
+	DIST(plateau),
+	DIST(shuffle),
+};
+
+static const struct dist *get_dist_by_name(const char *name)
+{
+	int i;
+	for (i = 0; i < ARRAY_SIZE(dist); i++) {
+	       if (!strcmp(dist[i].name, name))
+		       return &dist[i];
+	}
+	return NULL;
+}
+
+static void mode_copy(int *arr, int n)
+{
+	/* nothing */
+}
+
+static void mode_reverse(int *arr, int n)
+{
+	int i, j;
+	for (i = 0, j = n - 1; i < j; i++, j--)
+		SWAP(arr[i], arr[j]);
+}
+
+static void mode_reverse_1st_half(int *arr, int n)
+{
+	mode_reverse(arr, n / 2);
+}
+
+static void mode_reverse_2nd_half(int *arr, int n)
+{
+	int half = n / 2;
+	mode_reverse(arr + half, n - half);
+}
+
+static int compare_ints(const void *av, const void *bv)
+{
+	const int *ap = av, *bp = bv;
+	int a = *ap, b = *bp;
+	return (a > b) - (a < b);
+}
+
+static void mode_sort(int *arr, int n)
+{
+	QSORT(arr, n, compare_ints);
+}
+
+static void mode_dither(int *arr, int n)
+{
+	int i;
+	for (i = 0; i < n; i++)
+		arr[i] += i % 5;
+}
+
+static void unriffle(int *arr, int n, int *tmp)
+{
+	int i, j;
+	COPY_ARRAY(tmp, arr, n);
+	for (i = j = 0; i < n; i += 2)
+		arr[j++] = tmp[i];
+	for (i = 1; i < n; i += 2)
+		arr[j++] = tmp[i];
+}
+
+static void unriffle_recursively(int *arr, int n, int *tmp)
+{
+	if (n > 1) {
+		int half = n / 2;
+		unriffle(arr, n, tmp);
+		unriffle_recursively(arr, half, tmp);
+		unriffle_recursively(arr + half, n - half, tmp);
+	}
+}
+
+static void mode_unriffle(int *arr, int n)
+{
+	int *tmp;
+	ALLOC_ARRAY(tmp, n);
+	unriffle_recursively(arr, n, tmp);
+	free(tmp);
+}
+
+static unsigned int prev_pow2(unsigned int n)
+{
+	unsigned int pow2 = 1;
+	while (pow2 * 2 < n)
+		pow2 *= 2;
+	return pow2;
+}
+
+static void unriffle_recursively_skewed(int *arr, int n, int *tmp)
+{
+	if (n > 1) {
+		int pow2 = prev_pow2(n);
+		int rest = n - pow2;
+		unriffle(arr + pow2 - rest, rest * 2, tmp);
+		unriffle_recursively_skewed(arr, pow2, tmp);
+		unriffle_recursively_skewed(arr + pow2, rest, tmp);
+	}
+}
+
+static void mode_unriffle_skewed(int *arr, int n)
+{
+	int *tmp;
+	ALLOC_ARRAY(tmp, n);
+	unriffle_recursively_skewed(arr, n, tmp);
+	free(tmp);
+}
+
+#define MODE(name) { #name, mode_##name }
+
+static struct mode {
+	const char *name;
+	void (*fn)(int *arr, int n);
+} mode[] = {
+	MODE(copy),
+	MODE(reverse),
+	MODE(reverse_1st_half),
+	MODE(reverse_2nd_half),
+	MODE(sort),
+	MODE(dither),
+	MODE(unriffle),
+	MODE(unriffle_skewed),
+};
+
+static const struct mode *get_mode_by_name(const char *name)
+{
+	int i;
+	for (i = 0; i < ARRAY_SIZE(mode); i++) {
+	       if (!strcmp(mode[i].name, name))
+		       return &mode[i];
+	}
+	return NULL;
+}
+
+static int generate(int argc, const char **argv)
+{
+	const struct dist *dist = NULL;
+	const struct mode *mode = NULL;
+	int i, n, m, *arr;
+
+	if (argc != 4)
+		return 1;
+
+	dist = get_dist_by_name(argv[0]);
+	mode = get_mode_by_name(argv[1]);
+	n = strtol(argv[2], NULL, 10);
+	m = strtol(argv[3], NULL, 10);
+	if (!dist || !mode)
+		return 1;
+
+	ALLOC_ARRAY(arr, n);
+	dist->fn(arr, n, m);
+	mode->fn(arr, n);
+	for (i = 0; i < n; i++)
+		printf("%08x\n", arr[i]);
+	free(arr);
+	return 0;
+}
+
+static struct stats {
+	int get_next, set_next, compare;
+} stats;
+
+struct number {
+	int value, rank;
+	struct number *next;
+};
+
+static void *get_next_number(const void *a)
+{
+	stats.get_next++;
+	return ((const struct number *)a)->next;
+}
+
+static void set_next_number(void *a, void *b)
+{
+	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);
+}
+
+static void clear_numbers(struct number *list)
+{
+	while (list) {
+		struct number *next = list->next;
+		free(list);
+		list = next;
+	}
+}
+
+static int test(const struct dist *dist, const struct mode *mode, int n, int m)
+{
+	int *arr;
+	size_t i;
+	struct number *curr, *list, **tail;
+	int is_sorted = 1;
+	int is_stable = 1;
+	const char *verdict;
+	int result = -1;
+
+	ALLOC_ARRAY(arr, n);
+	dist->fn(arr, n, m);
+	mode->fn(arr, n);
+	for (i = 0, tail = &list; i < n; i++) {
+		curr = xmalloc(sizeof(*curr));
+		curr->value = arr[i];
+		curr->rank = i;
+		*tail = curr;
+		tail = &curr->next;
+	}
+	*tail = NULL;
+
+	stats.get_next = stats.set_next = stats.compare = 0;
+	list = llist_mergesort(list, get_next_number, set_next_number,
+			       compare_numbers);
+
+	QSORT(arr, n, compare_ints);
+	for (i = 0, curr = list; i < n && curr; i++, curr = curr->next) {
+		if (arr[i] != curr->value)
+			is_sorted = 0;
+		if (curr->next && curr->value == curr->next->value &&
+		    curr->rank >= curr->next->rank)
+			is_stable = 0;
+	}
+	if (i < n) {
+		verdict = "too short";
+	} else if (curr) {
+		verdict = "too long";
+	} else if (!is_sorted) {
+		verdict = "not sorted";
+	} else if (!is_stable) {
+		verdict = "unstable";
+	} else {
+		verdict = "OK";
+		result = 0;
+	}
+
+	printf("%-9s %-16s %8d %8d %8d %8d %8d %s\n",
+	       dist->name, mode->name, n, m, stats.get_next, stats.set_next,
+	       stats.compare, verdict);
+
+	clear_numbers(list);
+	free(arr);
+
+	return result;
+}
+
+/*
+ * A version of the qsort certification program from "Engineering a Sort
+ * Function" by Bentley and McIlroy, Software—Practice and Experience,
+ * Volume 23, Issue 11, 1249–1265 (November 1993).
+ */
+static int run_tests(int argc, const char **argv)
+{
+	const char *argv_default[] = { "100", "1023", "1024", "1025" };
+	if (!argc)
+		return run_tests(ARRAY_SIZE(argv_default), argv_default);
+	printf("%-9s %-16s %8s %8s %8s %8s %8s %s\n",
+	       "distribut", "mode", "n", "m", "get_next", "set_next",
+	       "compare", "verdict");
+	while (argc--) {
+		int i, j, m, n = strtol(*argv++, NULL, 10);
+		for (i = 0; i < ARRAY_SIZE(dist); i++) {
+			for (j = 0; j < ARRAY_SIZE(mode); j++) {
+				for (m = 1; m < 2 * n; m *= 2) {
+					if (test(&dist[i], &mode[j], n, m))
+						return 1;
+				}
+			}
+		}
+	}
+	return 0;
+}
+
+int cmd__mergesort(int argc, const char **argv)
+{
+	int i;
+	const char *sep;
+
+	if (argc == 6 && !strcmp(argv[1], "generate"))
+		return generate(argc - 2, argv + 2);
+	if (argc == 2 && !strcmp(argv[1], "sort"))
+		return sort_stdin();
+	if (argc > 1 && !strcmp(argv[1], "test"))
+		return run_tests(argc - 2, argv + 2);
+	fprintf(stderr, "usage: test-tool mergesort generate <distribution> <mode> <n> <m>\n");
+	fprintf(stderr, "   or: test-tool mergesort sort\n");
+	fprintf(stderr, "   or: test-tool mergesort test [<n>...]\n");
+	fprintf(stderr, "\n");
+	for (i = 0, sep = "distributions: "; i < ARRAY_SIZE(dist); i++, sep = ", ")
+		fprintf(stderr, "%s%s", sep, dist[i].name);
+	fprintf(stderr, "\n");
+	for (i = 0, sep = "modes: "; i < ARRAY_SIZE(mode); i++, sep = ", ")
+		fprintf(stderr, "%s%s", sep, mode[i].name);
+	fprintf(stderr, "\n");
+	return 129;
+}
diff --git a/t/helper/test-oid-array.c b/t/helper/test-oid-array.c
index b16cd0b..d1324d0 100644
--- a/t/helper/test-oid-array.c
+++ b/t/helper/test-oid-array.c
@@ -35,5 +35,9 @@
 		else
 			die("unknown command: %s", line.buf);
 	}
+
+	strbuf_release(&line);
+	oid_array_clear(&array);
+
 	return 0;
 }
diff --git a/t/helper/test-oidtree.c b/t/helper/test-oidtree.c
index 180ee28..d48a409 100644
--- a/t/helper/test-oidtree.c
+++ b/t/helper/test-oidtree.c
@@ -45,5 +45,8 @@
 			die("unknown command: %s", line.buf);
 		}
 	}
+
+	strbuf_release(&line);
+
 	return 0;
 }
diff --git a/t/helper/test-parse-options.c b/t/helper/test-parse-options.c
index 2051ce5..48d3cf6 100644
--- a/t/helper/test-parse-options.c
+++ b/t/helper/test-parse-options.c
@@ -14,7 +14,6 @@
 static char *string = NULL;
 static char *file = NULL;
 static int ambiguous;
-static struct string_list list = STRING_LIST_INIT_NODUP;
 
 static struct {
 	int called;
@@ -107,6 +106,8 @@
 		NULL
 	};
 	struct string_list expect = STRING_LIST_INIT_NODUP;
+	struct string_list list = STRING_LIST_INIT_NODUP;
+
 	struct option options[] = {
 		OPT_BOOL(0, "yes", &boolean, "get a boolean"),
 		OPT_BOOL('D', "no-doubt", &boolean, "begins with 'no-'"),
@@ -134,7 +135,6 @@
 		OPT_NOOP_NOARG(0, "obsolete"),
 		OPT_STRING_LIST(0, "list", &list, "str", "add str to list"),
 		OPT_GROUP("Magic arguments"),
-		OPT_ARGUMENT("quux", NULL, "means --quux"),
 		OPT_NUMBER_CALLBACK(&integer, "set integer to NUM",
 			number_callback),
 		{ OPTION_COUNTUP, '+', NULL, &boolean, NULL, "same as -b",
@@ -186,5 +186,9 @@
 	for (i = 0; i < argc; i++)
 		show(&expect, &ret, "arg %02d: %s", i, argv[i]);
 
+	expect.strdup_strings = 1;
+	string_list_clear(&expect, 0);
+	string_list_clear(&list, 0);
+
 	return ret;
 }
diff --git a/t/helper/test-prio-queue.c b/t/helper/test-prio-queue.c
index f402844..133b5e6 100644
--- a/t/helper/test-prio-queue.c
+++ b/t/helper/test-prio-queue.c
@@ -46,5 +46,7 @@
 		}
 	}
 
+	clear_prio_queue(&pq);
+
 	return 0;
 }
diff --git a/t/helper/test-read-midx.c b/t/helper/test-read-midx.c
index 7c2eb11..9d6fa7a 100644
--- a/t/helper/test-read-midx.c
+++ b/t/helper/test-read-midx.c
@@ -3,6 +3,7 @@
 #include "midx.h"
 #include "repository.h"
 #include "object-store.h"
+#include "pack-bitmap.h"
 
 static int read_midx_file(const char *object_dir, int show_objects)
 {
@@ -60,12 +61,52 @@
 	return 0;
 }
 
+static int read_midx_checksum(const char *object_dir)
+{
+	struct multi_pack_index *m;
+
+	setup_git_directory();
+	m = load_multi_pack_index(object_dir, 1);
+	if (!m)
+		return 1;
+	printf("%s\n", hash_to_hex(get_midx_checksum(m)));
+	return 0;
+}
+
+static int read_midx_preferred_pack(const char *object_dir)
+{
+	struct multi_pack_index *midx = NULL;
+	struct bitmap_index *bitmap = NULL;
+
+	setup_git_directory();
+
+	midx = load_multi_pack_index(object_dir, 1);
+	if (!midx)
+		return 1;
+
+	bitmap = prepare_bitmap_git(the_repository);
+	if (!bitmap)
+		return 1;
+	if (!bitmap_is_midx(bitmap)) {
+		free_bitmap_index(bitmap);
+		return 1;
+	}
+
+	printf("%s\n", midx->pack_names[midx_preferred_pack(bitmap)]);
+	free_bitmap_index(bitmap);
+	return 0;
+}
+
 int cmd__read_midx(int argc, const char **argv)
 {
 	if (!(argc == 2 || argc == 3))
-		usage("read-midx [--show-objects] <object-dir>");
+		usage("read-midx [--show-objects|--checksum|--preferred-pack] <object-dir>");
 
 	if (!strcmp(argv[1], "--show-objects"))
 		return read_midx_file(argv[2], 1);
+	else if (!strcmp(argv[1], "--checksum"))
+		return read_midx_checksum(argv[2]);
+	else if (!strcmp(argv[1], "--preferred-pack"))
+		return read_midx_preferred_pack(argv[2]);
 	return read_midx_file(argv[1], 0);
 }
diff --git a/t/helper/test-run-command.c b/t/helper/test-run-command.c
index 7ae03dc..3c4fb86 100644
--- a/t/helper/test-run-command.c
+++ b/t/helper/test-run-command.c
@@ -60,8 +60,10 @@
 	int next;
 	int quiet, immediate, verbose, verbose_log, trace, write_junit_xml;
 };
-#define TESTSUITE_INIT \
-	{ STRING_LIST_INIT_DUP, STRING_LIST_INIT_DUP, -1, 0, 0, 0, 0, 0, 0 }
+#define TESTSUITE_INIT { \
+	.tests = STRING_LIST_INIT_DUP, \
+	.failed = STRING_LIST_INIT_DUP, \
+}
 
 static int next_test(struct child_process *cp, struct strbuf *err, void *cb,
 		     void **task_cb)
@@ -142,9 +144,6 @@
 		OPT_END()
 	};
 
-	memset(&suite, 0, sizeof(suite));
-	suite.tests.strdup_strings = suite.failed.strdup_strings = 1;
-
 	argc = parse_options(argc, argv, NULL, options,
 			testsuite_usage, PARSE_OPT_STOP_AT_NON_OPTION);
 
diff --git a/t/helper/test-serve-v2.c b/t/helper/test-serve-v2.c
index aee35e5..28e905a 100644
--- a/t/helper/test-serve-v2.c
+++ b/t/helper/test-serve-v2.c
@@ -10,12 +10,12 @@
 
 int cmd__serve_v2(int argc, const char **argv)
 {
-	struct serve_options opts = SERVE_OPTIONS_INIT;
-
+	int stateless_rpc = 0;
+	int advertise_capabilities = 0;
 	struct option options[] = {
-		OPT_BOOL(0, "stateless-rpc", &opts.stateless_rpc,
+		OPT_BOOL(0, "stateless-rpc", &stateless_rpc,
 			 N_("quit after a single request/response exchange")),
-		OPT_BOOL(0, "advertise-capabilities", &opts.advertise_capabilities,
+		OPT_BOOL(0, "advertise-capabilities", &advertise_capabilities,
 			 N_("exit immediately after advertising capabilities")),
 		OPT_END()
 	};
@@ -25,7 +25,11 @@
 	argc = parse_options(argc, argv, prefix, options, serve_usage,
 			     PARSE_OPT_KEEP_DASHDASH |
 			     PARSE_OPT_KEEP_UNKNOWN);
-	serve(&opts);
+
+	if (advertise_capabilities)
+		protocol_v2_advertise_capabilities();
+	else
+		protocol_v2_serve_loop(stateless_rpc);
 
 	return 0;
 }
diff --git a/t/helper/test-simple-ipc.c b/t/helper/test-simple-ipc.c
index 42040ef..28365ff 100644
--- a/t/helper/test-simple-ipc.c
+++ b/t/helper/test-simple-ipc.c
@@ -9,6 +9,7 @@
 #include "parse-options.h"
 #include "thread-utils.h"
 #include "strvec.h"
+#include "run-command.h"
 
 #ifndef SUPPORTS_SIMPLE_IPC
 int cmd__simple_ipc(int argc, const char **argv)
@@ -112,7 +113,7 @@
 /*
  * The client sent a command followed by a (possibly very) large buffer.
  */
-static int app__sendbytes_command(const char *received,
+static int app__sendbytes_command(const char *received, size_t received_len,
 				  ipc_server_reply_cb *reply_cb,
 				  struct ipc_server_reply_data *reply_data)
 {
@@ -123,6 +124,13 @@
 	int errs = 0;
 	int ret;
 
+	/*
+	 * The test is setup to send:
+	 *     "sendbytes" SP <n * char>
+	 */
+	if (received_len < strlen("sendbytes "))
+		BUG("received_len is short in app__sendbytes_command");
+
 	if (skip_prefix(received, "sendbytes ", &p))
 		len_ballast = strlen(p);
 
@@ -160,7 +168,7 @@
  * by this application.
  */
 static int test_app_cb(void *application_data,
-		       const char *command,
+		       const char *command, size_t command_len,
 		       ipc_server_reply_cb *reply_cb,
 		       struct ipc_server_reply_data *reply_data)
 {
@@ -173,7 +181,7 @@
 	if (application_data != (void*)&my_app_data)
 		BUG("application_cb: application_data pointer wrong");
 
-	if (!strcmp(command, "quit")) {
+	if (command_len == 4 && !strncmp(command, "quit", 4)) {
 		/*
 		 * The client sent a "quit" command.  This is an async
 		 * request for the server to shutdown.
@@ -193,22 +201,23 @@
 		return SIMPLE_IPC_QUIT;
 	}
 
-	if (!strcmp(command, "ping")) {
+	if (command_len == 4 && !strncmp(command, "ping", 4)) {
 		const char *answer = "pong";
 		return reply_cb(reply_data, answer, strlen(answer));
 	}
 
-	if (!strcmp(command, "big"))
+	if (command_len == 3 && !strncmp(command, "big", 3))
 		return app__big_command(reply_cb, reply_data);
 
-	if (!strcmp(command, "chunk"))
+	if (command_len == 5 && !strncmp(command, "chunk", 5))
 		return app__chunk_command(reply_cb, reply_data);
 
-	if (!strcmp(command, "slow"))
+	if (command_len == 4 && !strncmp(command, "slow", 4))
 		return app__slow_command(reply_cb, reply_data);
 
-	if (starts_with(command, "sendbytes "))
-		return app__sendbytes_command(command, reply_cb, reply_data);
+	if (command_len >= 10 && starts_with(command, "sendbytes "))
+		return app__sendbytes_command(command, command_len,
+					      reply_cb, reply_data);
 
 	return app__unhandled_command(command, reply_cb, reply_data);
 }
@@ -259,183 +268,69 @@
 	 */
 	ret = ipc_server_run(cl_args.path, &opts, test_app_cb, (void*)&my_app_data);
 	if (ret == -2)
-		error(_("socket/pipe already in use: '%s'"), cl_args.path);
+		error("socket/pipe already in use: '%s'", cl_args.path);
 	else if (ret == -1)
-		error_errno(_("could not start server on: '%s'"), cl_args.path);
+		error_errno("could not start server on: '%s'", cl_args.path);
 
 	return ret;
 }
 
-#ifndef GIT_WINDOWS_NATIVE
-/*
- * This is adapted from `daemonize()`.  Use `fork()` to directly create and
- * run the daemon in a child process.
- */
-static int spawn_server(pid_t *pid)
+static start_bg_wait_cb bg_wait_cb;
+
+static int bg_wait_cb(const struct child_process *cp, void *cb_data)
 {
-	struct ipc_server_opts opts = {
-		.nr_threads = cl_args.nr_threads,
-	};
+	int s = ipc_get_active_state(cl_args.path);
 
-	*pid = fork();
+	switch (s) {
+	case IPC_STATE__LISTENING:
+		/* child is "ready" */
+		return 0;
 
-	switch (*pid) {
-	case 0:
-		if (setsid() == -1)
-			error_errno(_("setsid failed"));
-		close(0);
-		close(1);
-		close(2);
-		sanitize_stdfds();
-
-		return ipc_server_run(cl_args.path, &opts, test_app_cb,
-				      (void*)&my_app_data);
-
-	case -1:
-		return error_errno(_("could not spawn daemon in the background"));
+	case IPC_STATE__NOT_LISTENING:
+	case IPC_STATE__PATH_NOT_FOUND:
+		/* give child more time */
+		return 1;
 
 	default:
-		return 0;
-	}
-}
-#else
-/*
- * Conceptually like `daemonize()` but different because Windows does not
- * have `fork(2)`.  Spawn a normal Windows child process but without the
- * limitations of `start_command()` and `finish_command()`.
- */
-static int spawn_server(pid_t *pid)
-{
-	char test_tool_exe[MAX_PATH];
-	struct strvec args = STRVEC_INIT;
-	int in, out;
-
-	GetModuleFileNameA(NULL, test_tool_exe, MAX_PATH);
-
-	in = open("/dev/null", O_RDONLY);
-	out = open("/dev/null", O_WRONLY);
-
-	strvec_push(&args, test_tool_exe);
-	strvec_push(&args, "simple-ipc");
-	strvec_push(&args, "run-daemon");
-	strvec_pushf(&args, "--name=%s", cl_args.path);
-	strvec_pushf(&args, "--threads=%d", cl_args.nr_threads);
-
-	*pid = mingw_spawnvpe(args.v[0], args.v, NULL, NULL, in, out, out);
-	close(in);
-	close(out);
-
-	strvec_clear(&args);
-
-	if (*pid < 0)
-		return error(_("could not spawn daemon in the background"));
-
-	return 0;
-}
-#endif
-
-/*
- * This is adapted from `wait_or_whine()`.  Watch the child process and
- * let it get started and begin listening for requests on the socket
- * before reporting our success.
- */
-static int wait_for_server_startup(pid_t pid_child)
-{
-	int status;
-	pid_t pid_seen;
-	enum ipc_active_state s;
-	time_t time_limit, now;
-
-	time(&time_limit);
-	time_limit += cl_args.max_wait_sec;
-
-	for (;;) {
-		pid_seen = waitpid(pid_child, &status, WNOHANG);
-
-		if (pid_seen == -1)
-			return error_errno(_("waitpid failed"));
-
-		else if (pid_seen == 0) {
-			/*
-			 * The child is still running (this should be
-			 * the normal case).  Try to connect to it on
-			 * the socket and see if it is ready for
-			 * business.
-			 *
-			 * If there is another daemon already running,
-			 * our child will fail to start (possibly
-			 * after a timeout on the lock), but we don't
-			 * care (who responds) if the socket is live.
-			 */
-			s = ipc_get_active_state(cl_args.path);
-			if (s == IPC_STATE__LISTENING)
-				return 0;
-
-			time(&now);
-			if (now > time_limit)
-				return error(_("daemon not online yet"));
-
-			continue;
-		}
-
-		else if (pid_seen == pid_child) {
-			/*
-			 * The new child daemon process shutdown while
-			 * it was starting up, so it is not listening
-			 * on the socket.
-			 *
-			 * Try to ping the socket in the odd chance
-			 * that another daemon started (or was already
-			 * running) while our child was starting.
-			 *
-			 * Again, we don't care who services the socket.
-			 */
-			s = ipc_get_active_state(cl_args.path);
-			if (s == IPC_STATE__LISTENING)
-				return 0;
-
-			/*
-			 * We don't care about the WEXITSTATUS() nor
-			 * any of the WIF*(status) values because
-			 * `cmd__simple_ipc()` does the `!!result`
-			 * trick on all function return values.
-			 *
-			 * So it is sufficient to just report the
-			 * early shutdown as an error.
-			 */
-			return error(_("daemon failed to start"));
-		}
-
-		else
-			return error(_("waitpid is confused"));
+	case IPC_STATE__INVALID_PATH:
+	case IPC_STATE__OTHER_ERROR:
+		/* all the time in world won't help */
+		return -1;
 	}
 }
 
-/*
- * This process will start a simple-ipc server in a background process and
- * wait for it to become ready.  This is like `daemonize()` but gives us
- * more control and better error reporting (and makes it easier to write
- * unit tests).
- */
 static int daemon__start_server(void)
 {
-	pid_t pid_child;
-	int ret;
+	struct child_process cp = CHILD_PROCESS_INIT;
+	enum start_bg_result sbgr;
 
-	/*
-	 * Run the actual daemon in a background process.
-	 */
-	ret = spawn_server(&pid_child);
-	if (pid_child <= 0)
-		return ret;
+	strvec_push(&cp.args, "test-tool");
+	strvec_push(&cp.args, "simple-ipc");
+	strvec_push(&cp.args, "run-daemon");
+	strvec_pushf(&cp.args, "--name=%s", cl_args.path);
+	strvec_pushf(&cp.args, "--threads=%d", cl_args.nr_threads);
 
-	/*
-	 * Let the parent wait for the child process to get started
-	 * and begin listening for requests on the socket.
-	 */
-	ret = wait_for_server_startup(pid_child);
+	cp.no_stdin = 1;
+	cp.no_stdout = 1;
+	cp.no_stderr = 1;
 
-	return ret;
+	sbgr = start_bg_command(&cp, bg_wait_cb, NULL, cl_args.max_wait_sec);
+
+	switch (sbgr) {
+	case SBGR_READY:
+		return 0;
+
+	default:
+	case SBGR_ERROR:
+	case SBGR_CB_ERROR:
+		return error("daemon failed to start");
+
+	case SBGR_TIMEOUT:
+		return error("daemon not online yet");
+
+	case SBGR_DIED:
+		return error("daemon terminated");
+	}
 }
 
 /*
@@ -488,7 +383,9 @@
 	options.wait_if_busy = 1;
 	options.wait_if_not_found = 0;
 
-	if (!ipc_client_send_command(cl_args.path, &options, command, &buf)) {
+	if (!ipc_client_send_command(cl_args.path, &options,
+				     command, strlen(command),
+				     &buf)) {
 		if (buf.len) {
 			printf("%s\n", buf.buf);
 			fflush(stdout);
@@ -538,7 +435,7 @@
 
 		time(&now);
 		if (now > time_limit)
-			return error(_("daemon has not shutdown yet"));
+			return error("daemon has not shutdown yet");
 	}
 }
 
@@ -556,7 +453,9 @@
 	strbuf_addstr(&buf_send, "sendbytes ");
 	strbuf_addchars(&buf_send, byte, bytecount);
 
-	if (!ipc_client_send_command(path, options, buf_send.buf, &buf_resp)) {
+	if (!ipc_client_send_command(path, options,
+				     buf_send.buf, buf_send.len,
+				     &buf_resp)) {
 		strbuf_rtrim(&buf_resp);
 		printf("sent:%c%08d %s\n", byte, bytecount, buf_resp.buf);
 		fflush(stdout);
diff --git a/t/helper/test-submodule-nested-repo-config.c b/t/helper/test-submodule-nested-repo-config.c
index e3f11ff..dc1c14b 100644
--- a/t/helper/test-submodule-nested-repo-config.c
+++ b/t/helper/test-submodule-nested-repo-config.c
@@ -11,15 +11,13 @@
 int cmd__submodule_nested_repo_config(int argc, const char **argv)
 {
 	struct repository subrepo;
-	const struct submodule *sub;
 
 	if (argc < 3)
 		die_usage(argv, "Wrong number of arguments.");
 
 	setup_git_directory();
 
-	sub = submodule_from_path(the_repository, null_oid(), argv[1]);
-	if (repo_submodule_init(&subrepo, the_repository, sub)) {
+	if (repo_submodule_init(&subrepo, the_repository, argv[1], null_oid())) {
 		die_usage(argv, "Submodule not found.");
 	}
 
diff --git a/t/lib-bitmap.sh b/t/lib-bitmap.sh
index fe3f98b..21d0392 100644
--- a/t/lib-bitmap.sh
+++ b/t/lib-bitmap.sh
@@ -1,3 +1,6 @@
+# Helpers for scripts testing bitmap functionality; see t5310 for
+# example usage.
+
 # Compare a file containing rev-list bitmap traversal output to its non-bitmap
 # counterpart. You can't just use test_cmp for this, because the two produce
 # subtly different output:
@@ -24,3 +27,240 @@
 	test_cmp "$1.normalized" "$2.normalized" &&
 	rm -f "$1.normalized" "$2.normalized"
 }
+
+# To ensure the logic for "maximal commits" is exercised, make
+# the repository a bit more complicated.
+#
+#    other                         second
+#      *                             *
+# (99 commits)                  (99 commits)
+#      *                             *
+#      |\                           /|
+#      | * octo-other  octo-second * |
+#      |/|\_________  ____________/|\|
+#      | \          \/  __________/  |
+#      |  | ________/\ /             |
+#      *  |/          * merge-right  *
+#      | _|__________/ \____________ |
+#      |/ |                         \|
+# (l1) *  * merge-left               * (r1)
+#      | / \________________________ |
+#      |/                           \|
+# (l2) *                             * (r2)
+#       \___________________________ |
+#                                   \|
+#                                    * (base)
+#
+# We only push bits down the first-parent history, which
+# makes some of these commits unimportant!
+#
+# The important part for the maximal commit algorithm is how
+# the bitmasks are extended. Assuming starting bit positions
+# for second (bit 0) and other (bit 1), the bitmasks at the
+# end should be:
+#
+#      second: 1       (maximal, selected)
+#       other: 01      (maximal, selected)
+#      (base): 11 (maximal)
+#
+# This complicated history was important for a previous
+# version of the walk that guarantees never walking a
+# commit multiple times. That goal might be important
+# again, so preserve this complicated case. For now, this
+# test will guarantee that the bitmaps are computed
+# correctly, even with the repeat calculations.
+setup_bitmap_history() {
+	test_expect_success 'setup repo with moderate-sized history' '
+		test_commit_bulk --id=file 10 &&
+		git branch -M second &&
+		git checkout -b other HEAD~5 &&
+		test_commit_bulk --id=side 10 &&
+
+		# add complicated history setup, including merges and
+		# ambiguous merge-bases
+
+		git checkout -b merge-left other~2 &&
+		git merge second~2 -m "merge-left" &&
+
+		git checkout -b merge-right second~1 &&
+		git merge other~1 -m "merge-right" &&
+
+		git checkout -b octo-second second &&
+		git merge merge-left merge-right -m "octopus-second" &&
+
+		git checkout -b octo-other other &&
+		git merge merge-left merge-right -m "octopus-other" &&
+
+		git checkout other &&
+		git merge octo-other -m "pull octopus" &&
+
+		git checkout second &&
+		git merge octo-second -m "pull octopus" &&
+
+		# Remove these branches so they are not selected
+		# as bitmap tips
+		git branch -D merge-left &&
+		git branch -D merge-right &&
+		git branch -D octo-other &&
+		git branch -D octo-second &&
+
+		# add padding to make these merges less interesting
+		# and avoid having them selected for bitmaps
+		test_commit_bulk --id=file 100 &&
+		git checkout other &&
+		test_commit_bulk --id=side 100 &&
+		git checkout second &&
+
+		bitmaptip=$(git rev-parse second) &&
+		blob=$(echo tagged-blob | git hash-object -w --stdin) &&
+		git tag tagged-blob $blob
+	'
+}
+
+rev_list_tests_head () {
+	test_expect_success "counting commits via bitmap ($state, $branch)" '
+		git rev-list --count $branch >expect &&
+		git rev-list --use-bitmap-index --count $branch >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "counting partial commits via bitmap ($state, $branch)" '
+		git rev-list --count $branch~5..$branch >expect &&
+		git rev-list --use-bitmap-index --count $branch~5..$branch >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "counting commits with limit ($state, $branch)" '
+		git rev-list --count -n 1 $branch >expect &&
+		git rev-list --use-bitmap-index --count -n 1 $branch >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "counting non-linear history ($state, $branch)" '
+		git rev-list --count other...second >expect &&
+		git rev-list --use-bitmap-index --count other...second >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "counting commits with limiting ($state, $branch)" '
+		git rev-list --count $branch -- 1.t >expect &&
+		git rev-list --use-bitmap-index --count $branch -- 1.t >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "counting objects via bitmap ($state, $branch)" '
+		git rev-list --count --objects $branch >expect &&
+		git rev-list --use-bitmap-index --count --objects $branch >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success "enumerate commits ($state, $branch)" '
+		git rev-list --use-bitmap-index $branch >actual &&
+		git rev-list $branch >expect &&
+		test_bitmap_traversal --no-confirm-bitmaps expect actual
+	'
+
+	test_expect_success "enumerate --objects ($state, $branch)" '
+		git rev-list --objects --use-bitmap-index $branch >actual &&
+		git rev-list --objects $branch >expect &&
+		test_bitmap_traversal expect actual
+	'
+
+	test_expect_success "bitmap --objects handles non-commit objects ($state, $branch)" '
+		git rev-list --objects --use-bitmap-index $branch tagged-blob >actual &&
+		grep $blob actual
+	'
+}
+
+rev_list_tests () {
+	state=$1
+
+	for branch in "second" "other"
+	do
+		rev_list_tests_head
+	done
+}
+
+basic_bitmap_tests () {
+	tip="$1"
+	test_expect_success 'rev-list --test-bitmap verifies bitmaps' "
+		git rev-list --test-bitmap "${tip:-HEAD}"
+	"
+
+	rev_list_tests 'full bitmap'
+
+	test_expect_success 'clone from bitmapped repository' '
+		rm -fr clone.git &&
+		git clone --no-local --bare . clone.git &&
+		git rev-parse HEAD >expect &&
+		git --git-dir=clone.git rev-parse HEAD >actual &&
+		test_cmp expect actual
+	'
+
+	test_expect_success 'partial clone from bitmapped repository' '
+		test_config uploadpack.allowfilter true &&
+		rm -fr partial-clone.git &&
+		git clone --no-local --bare --filter=blob:none . partial-clone.git &&
+		(
+			cd partial-clone.git &&
+			pack=$(echo objects/pack/*.pack) &&
+			git verify-pack -v "$pack" >have &&
+			awk "/blob/ { print \$1 }" <have >blobs &&
+			# we expect this single blob because of the direct ref
+			git rev-parse refs/tags/tagged-blob >expect &&
+			test_cmp expect blobs
+		)
+	'
+
+	test_expect_success 'setup further non-bitmapped commits' '
+		test_commit_bulk --id=further 10
+	'
+
+	rev_list_tests 'partial bitmap'
+
+	test_expect_success 'fetch (partial 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 'enumerating progress counts pack-reused objects' '
+		count=$(git rev-list --objects --all --count) &&
+		git repack -adb &&
+
+		# check first with only reused objects; confirm that our
+		# progress showed the right number, and also that we did
+		# pack-reuse as expected.  Check only the final "done"
+		# line of the meter (there may be an arbitrary number of
+		# intermediate lines ending with CR).
+		GIT_PROGRESS_DELAY=0 \
+			git pack-objects --all --stdout --progress \
+			</dev/null >/dev/null 2>stderr &&
+		grep "Enumerating objects: $count, done" stderr &&
+		grep "pack-reused $count" stderr &&
+
+		# now the same but with one non-reused object
+		git commit --allow-empty -m "an extra commit object" &&
+		GIT_PROGRESS_DELAY=0 \
+			git pack-objects --all --stdout --progress \
+			</dev/null >/dev/null 2>stderr &&
+		grep "Enumerating objects: $((count+1)), done" stderr &&
+		grep "pack-reused $count" stderr
+	'
+}
+
+# have_delta <obj> <expected_base>
+#
+# Note that because this relies on cat-file, it might find _any_ copy of an
+# object in the repository. The caller is responsible for making sure
+# there's only one (e.g., via "repack -ad", or having just fetched a copy).
+have_delta () {
+	echo $2 >expect &&
+	echo $1 | git cat-file --batch-check="%(deltabase)" >actual &&
+	test_cmp expect actual
+}
+
+midx_checksum () {
+	test-tool read-midx --checksum "$1"
+}
diff --git a/t/lib-diff-data.sh b/t/lib-diff-data.sh
new file mode 100644
index 0000000..c64ec18
--- /dev/null
+++ b/t/lib-diff-data.sh
@@ -0,0 +1,22 @@
+COPYING_test_data () {
+	cat <<\EOF
+
+ Note that the only valid version of the GPL as far as this project
+ is concerned is _this_ particular version of the license (ie v2, not
+ v2.2 or v3.x or whatever), unless explicitly otherwise stated.
+
+ HOWEVER, in order to allow a migration to GPLv3 if that seems like
+ a good idea, I also ask that people involved with the project make
+ their preferences known. In particular, if you trust me to make that
+ decision, you might note so in your copyright message, ie something
+ like
+
+	This file is licensed under the GPL v2, or a later version
+	at the discretion of Linus.
+
+  might avoid issues. But we can also just decide to synchronize and
+  contact all copyright holders on record if/when the occasion arises.
+
+			Linus Torvalds
+EOF
+}
diff --git a/t/lib-diff.sh b/t/lib-diff.sh
index 2de880f..c4606bd 100644
--- a/t/lib-diff.sh
+++ b/t/lib-diff.sh
@@ -1,3 +1,5 @@
+. "$TEST_DIRECTORY"/lib-diff-data.sh
+
 :
 
 sanitize_diff_raw='/^:/s/ '"\($OID_REGEX\)"' '"\($OID_REGEX\)"' \([A-Z]\)[0-9]*	/ \1 \2 \3#	/'
diff --git a/t/lib-diff/COPYING b/t/lib-diff/COPYING
deleted file mode 100644
index 6ff87c4..0000000
--- a/t/lib-diff/COPYING
+++ /dev/null
@@ -1,361 +0,0 @@
-
- Note that the only valid version of the GPL as far as this project
- is concerned is _this_ particular version of the license (ie v2, not
- v2.2 or v3.x or whatever), unless explicitly otherwise stated.
-
- HOWEVER, in order to allow a migration to GPLv3 if that seems like
- a good idea, I also ask that people involved with the project make
- their preferences known. In particular, if you trust me to make that
- decision, you might note so in your copyright message, ie something
- like
-
-	This file is licensed under the GPL v2, or a later version
-	at the discretion of Linus.
-
-  might avoid issues. But we can also just decide to synchronize and
-  contact all copyright holders on record if/when the occasion arises.
-
-			Linus Torvalds
-
-----------------------------------------
-
-		    GNU GENERAL PUBLIC LICENSE
-		       Version 2, June 1991
-
- Copyright (C) 1989, 1991 Free Software Foundation, Inc.
-                       59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
-
-			    Preamble
-
-  The licenses for most software are designed to take away your
-freedom to share and change it.  By contrast, the GNU General Public
-License is intended to guarantee your freedom to share and change free
-software--to make sure the software is free for all its users.  This
-General Public License applies to most of the Free Software
-Foundation's software and to any other program whose authors commit to
-using it.  (Some other Free Software Foundation software is covered by
-the GNU Library General Public License instead.)  You can apply it to
-your programs, too.
-
-  When we speak of free software, we are referring to freedom, not
-price.  Our General Public Licenses are designed to make sure that you
-have the freedom to distribute copies of free software (and charge for
-this service if you wish), that you receive source code or can get it
-if you want it, that you can change the software or use pieces of it
-in new free programs; and that you know you can do these things.
-
-  To protect your rights, we need to make restrictions that forbid
-anyone to deny you these rights or to ask you to surrender the rights.
-These restrictions translate to certain responsibilities for you if you
-distribute copies of the software, or if you modify it.
-
-  For example, if you distribute copies of such a program, whether
-gratis or for a fee, you must give the recipients all the rights that
-you have.  You must make sure that they, too, receive or can get the
-source code.  And you must show them these terms so they know their
-rights.
-
-  We protect your rights with two steps: (1) copyright the software, and
-(2) offer you this license which gives you legal permission to copy,
-distribute and/or modify the software.
-
-  Also, for each author's protection and ours, we want to make certain
-that everyone understands that there is no warranty for this free
-software.  If the software is modified by someone else and passed on, we
-want its recipients to know that what they have is not the original, so
-that any problems introduced by others will not reflect on the original
-authors' reputations.
-
-  Finally, any free program is threatened constantly by software
-patents.  We wish to avoid the danger that redistributors of a free
-program will individually obtain patent licenses, in effect making the
-program proprietary.  To prevent this, we have made it clear that any
-patent must be licensed for everyone's free use or not licensed at all.
-
-  The precise terms and conditions for copying, distribution and
-modification follow.
-
-		    GNU GENERAL PUBLIC LICENSE
-   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
-
-  0. This License applies to any program or other work which contains
-a notice placed by the copyright holder saying it may be distributed
-under the terms of this General Public License.  The "Program", below,
-refers to any such program or work, and a "work based on the Program"
-means either the Program or any derivative work under copyright law:
-that is to say, a work containing the Program or a portion of it,
-either verbatim or with modifications and/or translated into another
-language.  (Hereinafter, translation is included without limitation in
-the term "modification".)  Each licensee is addressed as "you".
-
-Activities other than copying, distribution and modification are not
-covered by this License; they are outside its scope.  The act of
-running the Program is not restricted, and the output from the Program
-is covered only if its contents constitute a work based on the
-Program (independent of having been made by running the Program).
-Whether that is true depends on what the Program does.
-
-  1. You may copy and distribute verbatim copies of the Program's
-source code as you receive it, in any medium, provided that you
-conspicuously and appropriately publish on each copy an appropriate
-copyright notice and disclaimer of warranty; keep intact all the
-notices that refer to this License and to the absence of any warranty;
-and give any other recipients of the Program a copy of this License
-along with the Program.
-
-You may charge a fee for the physical act of transferring a copy, and
-you may at your option offer warranty protection in exchange for a fee.
-
-  2. You may modify your copy or copies of the Program or any portion
-of it, thus forming a work based on the Program, and copy and
-distribute such modifications or work under the terms of Section 1
-above, provided that you also meet all of these conditions:
-
-    a) You must cause the modified files to carry prominent notices
-    stating that you changed the files and the date of any change.
-
-    b) You must cause any work that you distribute or publish, that in
-    whole or in part contains or is derived from the Program or any
-    part thereof, to be licensed as a whole at no charge to all third
-    parties under the terms of this License.
-
-    c) If the modified program normally reads commands interactively
-    when run, you must cause it, when started running for such
-    interactive use in the most ordinary way, to print or display an
-    announcement including an appropriate copyright notice and a
-    notice that there is no warranty (or else, saying that you provide
-    a warranty) and that users may redistribute the program under
-    these conditions, and telling the user how to view a copy of this
-    License.  (Exception: if the Program itself is interactive but
-    does not normally print such an announcement, your work based on
-    the Program is not required to print an announcement.)
-
-These requirements apply to the modified work as a whole.  If
-identifiable sections of that work are not derived from the Program,
-and can be reasonably considered independent and separate works in
-themselves, then this License, and its terms, do not apply to those
-sections when you distribute them as separate works.  But when you
-distribute the same sections as part of a whole which is a work based
-on the Program, the distribution of the whole must be on the terms of
-this License, whose permissions for other licensees extend to the
-entire whole, and thus to each and every part regardless of who wrote it.
-
-Thus, it is not the intent of this section to claim rights or contest
-your rights to work written entirely by you; rather, the intent is to
-exercise the right to control the distribution of derivative or
-collective works based on the Program.
-
-In addition, mere aggregation of another work not based on the Program
-with the Program (or with a work based on the Program) on a volume of
-a storage or distribution medium does not bring the other work under
-the scope of this License.
-
-  3. You may copy and distribute the Program (or a work based on it,
-under Section 2) in object code or executable form under the terms of
-Sections 1 and 2 above provided that you also do one of the following:
-
-    a) Accompany it with the complete corresponding machine-readable
-    source code, which must be distributed under the terms of Sections
-    1 and 2 above on a medium customarily used for software interchange; or,
-
-    b) Accompany it with a written offer, valid for at least three
-    years, to give any third party, for a charge no more than your
-    cost of physically performing source distribution, a complete
-    machine-readable copy of the corresponding source code, to be
-    distributed under the terms of Sections 1 and 2 above on a medium
-    customarily used for software interchange; or,
-
-    c) Accompany it with the information you received as to the offer
-    to distribute corresponding source code.  (This alternative is
-    allowed only for noncommercial distribution and only if you
-    received the program in object code or executable form with such
-    an offer, in accord with Subsection b above.)
-
-The source code for a work means the preferred form of the work for
-making modifications to it.  For an executable work, complete source
-code means all the source code for all modules it contains, plus any
-associated interface definition files, plus the scripts used to
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-special exception, the source code distributed need not include
-anything that is normally distributed (in either source or binary
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-operating system on which the executable runs, unless that component
-itself accompanies the executable.
-
-If distribution of executable or object code is made by offering
-access to copy from a designated place, then offering equivalent
-access to copy the source code from the same place counts as
-distribution of the source code, even though third parties are not
-compelled to copy the source along with the object code.
-
-  4. You may not copy, modify, sublicense, or distribute the Program
-except as expressly provided under this License.  Any attempt
-otherwise to copy, modify, sublicense or distribute the Program is
-void, and will automatically terminate your rights under this License.
-However, parties who have received copies, or rights, from you under
-this License will not have their licenses terminated so long as such
-parties remain in full compliance.
-
-  5. You are not required to accept this License, since you have not
-signed it.  However, nothing else grants you permission to modify or
-distribute the Program or its derivative works.  These actions are
-prohibited by law if you do not accept this License.  Therefore, by
-modifying or distributing the Program (or any work based on the
-Program), you indicate your acceptance of this License to do so, and
-all its terms and conditions for copying, distributing or modifying
-the Program or works based on it.
-
-  6. Each time you redistribute the Program (or any work based on the
-Program), the recipient automatically receives a license from the
-original licensor to copy, distribute or modify the Program subject to
-these terms and conditions.  You may not impose any further
-restrictions on the recipients' exercise of the rights granted herein.
-You are not responsible for enforcing compliance by third parties to
-this License.
-
-  7. If, as a consequence of a court judgment or allegation of patent
-infringement or for any other reason (not limited to patent issues),
-conditions are imposed on you (whether by court order, agreement or
-otherwise) that contradict the conditions of this License, they do not
-excuse you from the conditions of this License.  If you cannot
-distribute so as to satisfy simultaneously your obligations under this
-License and any other pertinent obligations, then as a consequence you
-may not distribute the Program at all.  For example, if a patent
-license would not permit royalty-free redistribution of the Program by
-all those who receive copies directly or indirectly through you, then
-the only way you could satisfy both it and this License would be to
-refrain entirely from distribution of the Program.
-
-If any portion of this section is held invalid or unenforceable under
-any particular circumstance, the balance of the section is intended to
-apply and the section as a whole is intended to apply in other
-circumstances.
-
-It is not the purpose of this section to induce you to infringe any
-patents or other property right claims or to contest validity of any
-such claims; this section has the sole purpose of protecting the
-integrity of the free software distribution system, which is
-implemented by public license practices.  Many people have made
-generous contributions to the wide range of software distributed
-through that system in reliance on consistent application of that
-system; it is up to the author/donor to decide if he or she is willing
-to distribute software through any other system and a licensee cannot
-impose that choice.
-
-This section is intended to make thoroughly clear what is believed to
-be a consequence of the rest of this License.
-
-  8. If the distribution and/or use of the Program is restricted in
-certain countries either by patents or by copyrighted interfaces, the
-original copyright holder who places the Program under this License
-may add an explicit geographical distribution limitation excluding
-those countries, so that distribution is permitted only in or among
-countries not thus excluded.  In such case, this License incorporates
-the limitation as if written in the body of this License.
-
-  9. The Free Software Foundation may publish revised and/or new versions
-of the General Public License from time to time.  Such new versions will
-be similar in spirit to the present version, but may differ in detail to
-address new problems or concerns.
-
-Each version is given a distinguishing version number.  If the Program
-specifies a version number of this License which applies to it and "any
-later version", you have the option of following the terms and conditions
-either of that version or of any later version published by the Free
-Software Foundation.  If the Program does not specify a version number of
-this License, you may choose any version ever published by the Free Software
-Foundation.
-
-  10. If you wish to incorporate parts of the Program into other free
-programs whose distribution conditions are different, write to the author
-to ask for permission.  For software which is copyrighted by the Free
-Software Foundation, write to the Free Software Foundation; we sometimes
-make exceptions for this.  Our decision will be guided by the two goals
-of preserving the free status of all derivatives of our free software and
-of promoting the sharing and reuse of software generally.
-
-			    NO WARRANTY
-
-  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
-FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
-OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
-PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
-OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
-MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
-TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
-PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
-REPAIR OR CORRECTION.
-
-  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
-WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
-REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
-INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
-OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
-TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
-YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
-PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
-POSSIBILITY OF SUCH DAMAGES.
-
-		     END OF TERMS AND CONDITIONS
-
-	    How to Apply These Terms to Your New Programs
-
-  If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these terms.
-
-  To do so, attach the following notices to the program.  It is safest
-to attach them to the start of each source file to most effectively
-convey the exclusion of warranty; and each file should have at least
-the "copyright" line and a pointer to where the full notice is found.
-
-    <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) <year>  <name of author>
-
-    This program is free software; you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation; either version 2 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program; if not, write to the Free Software
-    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-
-
-Also add information on how to contact you by electronic and paper mail.
-
-If the program is interactive, make it output a short notice like this
-when it starts in an interactive mode:
-
-    Gnomovision version 69, Copyright (C) year name of author
-    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
-    This is free software, and you are welcome to redistribute it
-    under certain conditions; type `show c' for details.
-
-The hypothetical commands `show w' and `show c' should show the appropriate
-parts of the General Public License.  Of course, the commands you use may
-be called something other than `show w' and `show c'; they could even be
-mouse-clicks or menu items--whatever suits your program.
-
-You should also get your employer (if you work as a programmer) or your
-school, if any, to sign a "copyright disclaimer" for the program, if
-necessary.  Here is a sample; alter the names:
-
-  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
-  `Gnomovision' (which makes passes at compilers) written by James Hacker.
-
-  <signature of Ty Coon>, 1 April 1989
-  Ty Coon, President of Vice
-
-This General Public License does not permit incorporating your program into
-proprietary programs.  If your program is a subroutine library, you may
-consider it more useful to permit linking proprietary applications with the
-library.  If this is what you want to do, use the GNU Library General
-Public License instead of this License.
diff --git a/t/lib-diff/README b/t/lib-diff/README
deleted file mode 100644
index 548142c..0000000
--- a/t/lib-diff/README
+++ /dev/null
@@ -1,46 +0,0 @@
-////////////////////////////////////////////////////////////////
-
-	GIT - the stupid content tracker
-
-////////////////////////////////////////////////////////////////
-
-"git" can mean anything, depending on your mood.
-
- - random three-letter combination that is pronounceable, and not
-   actually used by any common UNIX command.  The fact that it is a
-   mispronunciation of "get" may or may not be relevant.
- - stupid. contemptible and despicable. simple. Take your pick from the
-   dictionary of slang.
- - "global information tracker": you're in a good mood, and it actually
-   works for you. Angels sing, and a light suddenly fills the room.
- - "goddamn idiotic truckload of sh*t": when it breaks
-
-Git is a fast, scalable, distributed revision control system with an
-unusually rich command set that provides both high-level operations
-and full access to internals.
-
-Git is an Open Source project covered by the GNU General Public License.
-It was originally written by Linus Torvalds with help of a group of
-hackers around the net. It is currently maintained by Junio C Hamano.
-
-Please read the file INSTALL for installation instructions.
-See Documentation/tutorial.txt to get started, then see
-Documentation/everyday.txt for a useful minimum set of commands,
-and "man git-commandname" for documentation of each command.
-CVS users may also want to read Documentation/cvs-migration.txt.
-
-Many Git online resources are accessible from http://git.or.cz/
-including full documentation and Git related tools.
-
-The user discussion and development of Git take place on the Git
-mailing list -- everyone is welcome to post bug reports, feature
-requests, comments and patches to git@vger.kernel.org. To subscribe
-to the list, send an email with just "subscribe git" in the body to
-majordomo@vger.kernel.org. The mailing list archives are available at
-http://marc.theaimsgroup.com/?l=git and other archival sites.
-
-The messages titled "A note from the maintainer", "What's in
-git.git (stable)" and "What's cooking in git.git (topics)" and
-the discussion following them on the mailing list give a good
-reference for project status, development direction and
-remaining tasks.
diff --git a/t/lib-gpg.sh b/t/lib-gpg.sh
index 9fc5241..f99ef3e 100644
--- a/t/lib-gpg.sh
+++ b/t/lib-gpg.sh
@@ -87,6 +87,34 @@
 	echo | gpg --homedir "${GNUPGHOME}" -b --rfc1991 >/dev/null
 '
 
+GPGSSH_KEY_PRIMARY="${GNUPGHOME}/ed25519_ssh_signing_key"
+GPGSSH_KEY_SECONDARY="${GNUPGHOME}/rsa_2048_ssh_signing_key"
+GPGSSH_KEY_UNTRUSTED="${GNUPGHOME}/untrusted_ssh_signing_key"
+GPGSSH_KEY_WITH_PASSPHRASE="${GNUPGHOME}/protected_ssh_signing_key"
+GPGSSH_KEY_PASSPHRASE="super_secret"
+GPGSSH_ALLOWED_SIGNERS="${GNUPGHOME}/ssh.all_valid.allowedSignersFile"
+
+GPGSSH_GOOD_SIGNATURE_TRUSTED='Good "git" signature for'
+GPGSSH_GOOD_SIGNATURE_UNTRUSTED='Good "git" signature with'
+GPGSSH_KEY_NOT_TRUSTED="No principal matched"
+GPGSSH_BAD_SIGNATURE="Signature verification failed"
+
+test_lazy_prereq GPGSSH '
+	ssh_version=$(ssh-keygen -Y find-principals -n "git" 2>&1)
+	test $? != 127 || exit 1
+	echo $ssh_version | grep -q "find-principals:missing signature file"
+	test $? = 0 || exit 1;
+	mkdir -p "${GNUPGHOME}" &&
+	chmod 0700 "${GNUPGHOME}" &&
+	ssh-keygen -t ed25519 -N "" -C "git ed25519 key" -f "${GPGSSH_KEY_PRIMARY}" >/dev/null &&
+	echo "\"principal with number 1\" $(cat "${GPGSSH_KEY_PRIMARY}.pub")" >> "${GPGSSH_ALLOWED_SIGNERS}" &&
+	ssh-keygen -t rsa -b 2048 -N "" -C "git rsa2048 key" -f "${GPGSSH_KEY_SECONDARY}" >/dev/null &&
+	echo "\"principal with number 2\" $(cat "${GPGSSH_KEY_SECONDARY}.pub")" >> "${GPGSSH_ALLOWED_SIGNERS}" &&
+	ssh-keygen -t ed25519 -N "${GPGSSH_KEY_PASSPHRASE}" -C "git ed25519 encrypted key" -f "${GPGSSH_KEY_WITH_PASSPHRASE}" >/dev/null &&
+	echo "\"principal with number 3\" $(cat "${GPGSSH_KEY_WITH_PASSPHRASE}.pub")" >> "${GPGSSH_ALLOWED_SIGNERS}" &&
+	ssh-keygen -t ed25519 -N "" -f "${GPGSSH_KEY_UNTRUSTED}" >/dev/null
+'
+
 sanitize_pgp() {
 	perl -ne '
 		/^-----END PGP/ and $in_pgp = 0;
diff --git a/t/lib-httpd.sh b/t/lib-httpd.sh
index d2edfa4..7828919 100644
--- a/t/lib-httpd.sh
+++ b/t/lib-httpd.sh
@@ -131,6 +131,7 @@
 	cp "$TEST_PATH"/passwd "$HTTPD_ROOT_PATH"
 	install_script incomplete-length-upload-pack-v2-http.sh
 	install_script incomplete-body-upload-pack-v2-http.sh
+	install_script error-no-report.sh
 	install_script broken-smart-http.sh
 	install_script error-smart-http.sh
 	install_script error.sh
diff --git a/t/lib-httpd/apache.conf b/t/lib-httpd/apache.conf
index afa91e3..497b9b9 100644
--- a/t/lib-httpd/apache.conf
+++ b/t/lib-httpd/apache.conf
@@ -81,8 +81,6 @@
 PassEnv GIT_CONFIG_NOSYSTEM
 PassEnv GIT_TEST_SIDEBAND_ALL
 
-SetEnvIf Git-Protocol ".*" GIT_PROTOCOL=$0
-
 Alias /dumb/ www/
 Alias /auth/dumb/ www/auth/dumb/
 
@@ -117,8 +115,14 @@
 	SetEnv GIT_EXEC_PATH ${GIT_EXEC_PATH}
 	SetEnv GIT_HTTP_EXPORT_ALL
 </LocationMatch>
+<LocationMatch /smart_v0/>
+	SetEnv GIT_EXEC_PATH ${GIT_EXEC_PATH}
+	SetEnv GIT_HTTP_EXPORT_ALL
+	SetEnv GIT_PROTOCOL
+</LocationMatch>
 ScriptAlias /smart/incomplete_length/git-upload-pack incomplete-length-upload-pack-v2-http.sh/
 ScriptAlias /smart/incomplete_body/git-upload-pack incomplete-body-upload-pack-v2-http.sh/
+ScriptAlias /smart/no_report/git-receive-pack error-no-report.sh/
 ScriptAliasMatch /error_git_upload_pack/(.*)/git-upload-pack error.sh/
 ScriptAliasMatch /smart_*[^/]*/(.*) ${GIT_EXEC_PATH}/git-http-backend/$1
 ScriptAlias /broken_smart/ broken-smart-http.sh/
@@ -134,6 +138,9 @@
 <Files incomplete-body-upload-pack-v2-http.sh>
 	Options ExecCGI
 </Files>
+<Files error-no-report.sh>
+	Options ExecCGI
+</Files>
 <Files broken-smart-http.sh>
 	Options ExecCGI
 </Files>
diff --git a/t/lib-httpd/error-no-report.sh b/t/lib-httpd/error-no-report.sh
new file mode 100644
index 0000000..39ff75b
--- /dev/null
+++ b/t/lib-httpd/error-no-report.sh
@@ -0,0 +1,6 @@
+echo "Content-Type: application/x-git-receive-pack-result"
+echo
+printf '0013\001000eunpack ok\n'
+printf '0015\002skipping report\n'
+printf '0009\0010000'
+printf '0000'
diff --git a/t/lib-midx.sh b/t/lib-midx.sh
new file mode 100644
index 0000000..1261994
--- /dev/null
+++ b/t/lib-midx.sh
@@ -0,0 +1,8 @@
+# test_midx_consistent <objdir>
+test_midx_consistent () {
+	ls $1/pack/pack-*.idx | xargs -n 1 basename | sort >expect &&
+	test-tool read-midx $1 | grep ^pack-.*\.idx$ | sort >actual &&
+
+	test_cmp expect actual &&
+	git multi-pack-index --object-dir=$1 verify
+}
diff --git a/t/lib-subtest.sh b/t/lib-subtest.sh
new file mode 100644
index 0000000..56ee927
--- /dev/null
+++ b/t/lib-subtest.sh
@@ -0,0 +1,95 @@
+write_sub_test_lib_test () {
+	name="$1" # stdin is the body of the test code
+	mkdir "$name" &&
+	write_script "$name/$name.sh" "$TEST_SHELL_PATH" <<-EOF &&
+	test_description='A test of test-lib.sh itself'
+
+	# Point to the t/test-lib.sh, which isn't in ../ as usual
+	. "\$TEST_DIRECTORY"/test-lib.sh
+	EOF
+	cat >>"$name/$name.sh"
+}
+
+_run_sub_test_lib_test_common () {
+	cmp_op="$1" want_code="$2" name="$3" # stdin is the body of the test code
+	shift 3
+
+	# intercept pseudo-options at the front of the argument list that we
+	# will not pass to child script
+	skip=
+	while test $# -gt 0
+	do
+		case "$1" in
+		--skip=*)
+			skip=${1#--*=}
+			shift
+			;;
+		*)
+			break
+			;;
+		esac
+	done
+
+	(
+		cd "$name" &&
+
+		# Pretend we're not running under a test harness, whether we
+		# are or not. The test-lib output depends on the setting of
+		# this variable, so we need a stable setting under which to run
+		# the sub-test.
+		sane_unset HARNESS_ACTIVE &&
+
+		export TEST_DIRECTORY &&
+		# The child test re-sources GIT-BUILD-OPTIONS and may thus
+		# override the test output directory. We thus pass it as an
+		# explicit override to the child.
+		TEST_OUTPUT_DIRECTORY_OVERRIDE=$(pwd) &&
+		export TEST_OUTPUT_DIRECTORY_OVERRIDE &&
+		GIT_SKIP_TESTS=$skip &&
+		export GIT_SKIP_TESTS &&
+		sane_unset GIT_TEST_FAIL_PREREQS &&
+		./"$name.sh" "$@" >out 2>err;
+		ret=$? &&
+		test "$ret" "$cmp_op" "$want_code"
+	)
+}
+
+write_and_run_sub_test_lib_test () {
+	name="$1" descr="$2" # stdin is the body of the test code
+	write_sub_test_lib_test "$@" || return 1
+	_run_sub_test_lib_test_common -eq 0 "$@"
+}
+
+write_and_run_sub_test_lib_test_err () {
+	name="$1" descr="$2" # stdin is the body of the test code
+	write_sub_test_lib_test "$@" || return 1
+	_run_sub_test_lib_test_common -eq 1 "$@"
+}
+
+run_sub_test_lib_test () {
+	_run_sub_test_lib_test_common -eq 0 "$@"
+}
+
+run_sub_test_lib_test_err () {
+	_run_sub_test_lib_test_common -eq 1 "$@"
+}
+
+_check_sub_test_lib_test_common () {
+	name="$1" &&
+	sed -e 's/^> //' -e 's/Z$//' >"$name"/expect.out &&
+	test_cmp "$name"/expect.out "$name"/out
+}
+
+check_sub_test_lib_test () {
+	name="$1" # stdin is the expected output from the test
+	_check_sub_test_lib_test_common "$name" &&
+	test_must_be_empty "$name"/err
+}
+
+check_sub_test_lib_test_err () {
+	name="$1" # stdin is the expected output from the test
+	_check_sub_test_lib_test_common "$name" &&
+	# expected error output is in descriptor 3
+	sed -e 's/^> //' -e 's/Z$//' <&3 >"$name"/expect.err &&
+	test_cmp "$name"/expect.err "$name"/err
+}
diff --git a/t/oid-info/oid b/t/oid-info/oid
index a754970..7547d2c 100644
--- a/t/oid-info/oid
+++ b/t/oid-info/oid
@@ -27,3 +27,5 @@
 numeric		sha256:0123456789012345678901234567890123456789012345678901234567890123
 deadbeef	sha1:deadbeefdeadbeefdeadbeefdeadbeefdeadbeef
 deadbeef	sha256:deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef
+deadbeef_short	sha1:deadbeefdeadbeefdeadbeefdeadbeefdeadbee
+deadbeef_short	sha256:deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbee
diff --git a/t/perf/aggregate.perl b/t/perf/aggregate.perl
index 82c0df4..575d200 100755
--- a/t/perf/aggregate.perl
+++ b/t/perf/aggregate.perl
@@ -17,8 +17,8 @@
 		my $rt = ((defined $1 ? $1 : 0.0)*60+$2)*60+$3;
 		return ($rt, $4, $5);
 	# size
-	} elsif ($line =~ /^\d+$/) {
-		return $&;
+	} elsif ($line =~ /^\s*(\d+)$/) {
+		return $1;
 	} else {
 		die "bad input line: $line";
 	}
diff --git a/t/perf/config b/t/perf/config
new file mode 100644
index 0000000..b92768b
--- /dev/null
+++ b/t/perf/config
@@ -0,0 +1,2 @@
+[gc]
+	auto = 0
diff --git a/t/perf/lib-bitmap.sh b/t/perf/lib-bitmap.sh
new file mode 100644
index 0000000..63d3bc7
--- /dev/null
+++ b/t/perf/lib-bitmap.sh
@@ -0,0 +1,69 @@
+# Helper functions for testing bitmap performance; see p5310.
+
+test_full_bitmap () {
+	test_perf 'simulated clone' '
+		git pack-objects --stdout --all </dev/null >/dev/null
+	'
+
+	test_perf 'simulated fetch' '
+		have=$(git rev-list HEAD~100 -1) &&
+		{
+			echo HEAD &&
+			echo ^$have
+		} | git pack-objects --revs --stdout >/dev/null
+	'
+
+	test_perf 'pack to file (bitmap)' '
+		git pack-objects --use-bitmap-index --all pack1b </dev/null >/dev/null
+	'
+
+	test_perf 'rev-list (commits)' '
+		git rev-list --all --use-bitmap-index >/dev/null
+	'
+
+	test_perf 'rev-list (objects)' '
+		git rev-list --all --use-bitmap-index --objects >/dev/null
+	'
+
+	test_perf 'rev-list with tag negated via --not --all (objects)' '
+		git rev-list perf-tag --not --all --use-bitmap-index --objects >/dev/null
+	'
+
+	test_perf 'rev-list with negative tag (objects)' '
+		git rev-list HEAD --not perf-tag --use-bitmap-index --objects >/dev/null
+	'
+
+	test_perf 'rev-list count with blob:none' '
+		git rev-list --use-bitmap-index --count --objects --all \
+			--filter=blob:none >/dev/null
+	'
+
+	test_perf 'rev-list count with blob:limit=1k' '
+		git rev-list --use-bitmap-index --count --objects --all \
+			--filter=blob:limit=1k >/dev/null
+	'
+
+	test_perf 'rev-list count with tree:0' '
+		git rev-list --use-bitmap-index --count --objects --all \
+			--filter=tree:0 >/dev/null
+	'
+
+	test_perf 'simulated partial clone' '
+		git pack-objects --stdout --all --filter=blob:none </dev/null >/dev/null
+	'
+}
+
+test_partial_bitmap () {
+	test_perf 'clone (partial bitmap)' '
+		git pack-objects --stdout --all </dev/null >/dev/null
+	'
+
+	test_perf 'pack to file (partial bitmap)' '
+		git pack-objects --use-bitmap-index --all pack2b </dev/null >/dev/null
+	'
+
+	test_perf 'rev-list with tree filter (partial bitmap)' '
+		git rev-list --use-bitmap-index --count --objects --all \
+			--filter=tree:0 >/dev/null
+	'
+}
diff --git a/t/perf/p0071-sort.sh b/t/perf/p0071-sort.sh
index 6e924f5..ed366e2 100755
--- a/t/perf/p0071-sort.sh
+++ b/t/perf/p0071-sort.sh
@@ -11,16 +11,42 @@
 	git cat-file --batch >unsorted
 '
 
-test_perf 'sort(1)' '
-	sort <unsorted >expect
+test_perf 'sort(1) unsorted' '
+	sort <unsorted >sorted
 '
 
-test_perf 'string_list_sort()' '
-	test-tool string-list sort <unsorted >actual
+test_expect_success 'reverse' '
+	sort -r <unsorted >reversed
 '
 
-test_expect_success 'string_list_sort() sorts like sort(1)' '
-	test_cmp_bin expect actual
-'
+for file in sorted reversed
+do
+	test_perf "sort(1) $file" "
+		sort <$file >actual
+	"
+done
+
+for file in unsorted sorted reversed
+do
+
+	test_perf "string_list_sort() $file" "
+		test-tool string-list sort <$file >actual
+	"
+
+	test_expect_success "string_list_sort() $file sorts like sort(1)" "
+		test_cmp_bin sorted actual
+	"
+done
+
+for file in unsorted sorted reversed
+do
+	test_perf "llist_mergesort() $file" "
+		test-tool mergesort sort <$file >actual
+	"
+
+	test_expect_success "llist_mergesort() $file sorts like sort(1)" "
+		test_cmp_bin sorted actual
+	"
+done
 
 test_done
diff --git a/t/perf/p3400-rebase.sh b/t/perf/p3400-rebase.sh
index 7a0bb29..43d5a34 100755
--- a/t/perf/p3400-rebase.sh
+++ b/t/perf/p3400-rebase.sh
@@ -18,7 +18,7 @@
 		test_tick &&
 		git commit -m commit$i unrelated-file$i &&
 		echo change$i >unrelated-file$i &&
-		test_seq 1000 | tac >>unrelated-file$i &&
+		test_seq 1000 | sort -nr >>unrelated-file$i &&
 		git add unrelated-file$i &&
 		test_tick &&
 		git commit -m commit$i-reverse unrelated-file$i ||
diff --git a/t/perf/p5310-pack-bitmaps.sh b/t/perf/p5310-pack-bitmaps.sh
index 452be01..7ad4f23 100755
--- a/t/perf/p5310-pack-bitmaps.sh
+++ b/t/perf/p5310-pack-bitmaps.sh
@@ -2,6 +2,7 @@
 
 test_description='Tests pack performance using bitmaps'
 . ./perf-lib.sh
+. "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
 
 test_perf_large_repo
 
@@ -25,56 +26,7 @@
 	git repack -ad
 '
 
-test_perf 'simulated clone' '
-	git pack-objects --stdout --all </dev/null >/dev/null
-'
-
-test_perf 'simulated fetch' '
-	have=$(git rev-list HEAD~100 -1) &&
-	{
-		echo HEAD &&
-		echo ^$have
-	} | git pack-objects --revs --stdout >/dev/null
-'
-
-test_perf 'pack to file (bitmap)' '
-	git pack-objects --use-bitmap-index --all pack1b </dev/null >/dev/null
-'
-
-test_perf 'rev-list (commits)' '
-	git rev-list --all --use-bitmap-index >/dev/null
-'
-
-test_perf 'rev-list (objects)' '
-	git rev-list --all --use-bitmap-index --objects >/dev/null
-'
-
-test_perf 'rev-list with tag negated via --not --all (objects)' '
-	git rev-list perf-tag --not --all --use-bitmap-index --objects >/dev/null
-'
-
-test_perf 'rev-list with negative tag (objects)' '
-	git rev-list HEAD --not perf-tag --use-bitmap-index --objects >/dev/null
-'
-
-test_perf 'rev-list count with blob:none' '
-	git rev-list --use-bitmap-index --count --objects --all \
-		--filter=blob:none >/dev/null
-'
-
-test_perf 'rev-list count with blob:limit=1k' '
-	git rev-list --use-bitmap-index --count --objects --all \
-		--filter=blob:limit=1k >/dev/null
-'
-
-test_perf 'rev-list count with tree:0' '
-	git rev-list --use-bitmap-index --count --objects --all \
-		--filter=tree:0 >/dev/null
-'
-
-test_perf 'simulated partial clone' '
-	git pack-objects --stdout --all --filter=blob:none </dev/null >/dev/null
-'
+test_full_bitmap
 
 test_expect_success 'create partial bitmap state' '
 	# pick a commit to represent the repo tip in the past
@@ -97,17 +49,6 @@
 	git update-ref HEAD $orig_tip
 '
 
-test_perf 'clone (partial bitmap)' '
-	git pack-objects --stdout --all </dev/null >/dev/null
-'
-
-test_perf 'pack to file (partial bitmap)' '
-	git pack-objects --use-bitmap-index --all pack2b </dev/null >/dev/null
-'
-
-test_perf 'rev-list with tree filter (partial bitmap)' '
-	git rev-list --use-bitmap-index --count --objects --all \
-		--filter=tree:0 >/dev/null
-'
+test_partial_bitmap
 
 test_done
diff --git a/t/perf/p5326-multi-pack-bitmaps.sh b/t/perf/p5326-multi-pack-bitmaps.sh
new file mode 100755
index 0000000..f2fa228
--- /dev/null
+++ b/t/perf/p5326-multi-pack-bitmaps.sh
@@ -0,0 +1,52 @@
+#!/bin/sh
+
+test_description='Tests performance using midx bitmaps'
+. ./perf-lib.sh
+. "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
+
+test_perf_large_repo
+
+# we need to create the tag up front such that it is covered by the repack and
+# thus by generated bitmaps.
+test_expect_success 'create tags' '
+	git tag --message="tag pointing to HEAD" perf-tag HEAD
+'
+
+test_expect_success 'start with bitmapped pack' '
+	git repack -adb
+'
+
+test_perf 'setup multi-pack index' '
+	git multi-pack-index write --bitmap
+'
+
+test_expect_success 'drop pack bitmap' '
+	rm -f .git/objects/pack/pack-*.bitmap
+'
+
+test_full_bitmap
+
+test_expect_success 'create partial bitmap state' '
+	# pick a commit to represent the repo tip in the past
+	cutoff=$(git rev-list HEAD~100 -1) &&
+	orig_tip=$(git rev-parse HEAD) &&
+
+	# now 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_done
diff --git a/t/perf/perf-lib.sh b/t/perf/perf-lib.sh
index f5ed092..780a740 100644
--- a/t/perf/perf-lib.sh
+++ b/t/perf/perf-lib.sh
@@ -27,6 +27,10 @@
 
 . ../test-lib.sh
 
+unset GIT_CONFIG_NOSYSTEM
+GIT_CONFIG_SYSTEM="$TEST_DIRECTORY/perf/config"
+export GIT_CONFIG_SYSTEM
+
 if test -n "$GIT_TEST_INSTALLED" -a -z "$PERF_SET_GIT_TEST_INSTALLED"
 then
 	error "Do not use GIT_TEST_INSTALLED with the perf tests.
@@ -230,6 +234,7 @@
 		test_ok_ "$1"
 	fi
 	"$TEST_DIRECTORY"/perf/min_time.perl test_time.* >"$base".result
+	rm test_time.*
 }
 
 test_perf () {
diff --git a/t/perf/run b/t/perf/run
index d19dec2..55219aa 100755
--- a/t/perf/run
+++ b/t/perf/run
@@ -74,7 +74,7 @@
 	mydir=$1
 
 	mydir_abs=$(cd $mydir && pwd)
-	mydir_abs_wrappers="$mydir_abs_wrappers/bin-wrappers"
+	mydir_abs_wrappers="$mydir_abs/bin-wrappers"
 	if test -d "$mydir_abs_wrappers"
 	then
 		GIT_TEST_INSTALLED=$mydir_abs_wrappers
diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index 5c342de..b007f0e 100755
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh
@@ -19,6 +19,7 @@
 '
 
 . ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-subtest.sh
 
 try_local_xy () {
 	local x="local" y="alsolocal" &&
@@ -66,95 +67,8 @@
 	:
 '
 
-_run_sub_test_lib_test_common () {
-	neg="$1" name="$2" descr="$3" # stdin is the body of the test code
-	shift 3
-
-	# intercept pseudo-options at the front of the argument list that we
-	# will not pass to child script
-	skip=
-	while test $# -gt 0
-	do
-		case "$1" in
-		--skip=*)
-			skip=${1#--*=}
-			shift
-			;;
-		*)
-			break
-			;;
-		esac
-	done
-
-	mkdir "$name" &&
-	(
-		# Pretend we're not running under a test harness, whether we
-		# are or not. The test-lib output depends on the setting of
-		# this variable, so we need a stable setting under which to run
-		# the sub-test.
-		sane_unset HARNESS_ACTIVE &&
-		cd "$name" &&
-		write_script "$name.sh" "$TEST_SHELL_PATH" <<-EOF &&
-		test_description='$descr (run in sub test-lib)
-
-		This is run in a sub test-lib so that we do not get incorrect
-		passing metrics
-		'
-
-		# Point to the t/test-lib.sh, which isn't in ../ as usual
-		. "\$TEST_DIRECTORY"/test-lib.sh
-		EOF
-		cat >>"$name.sh" &&
-		export TEST_DIRECTORY &&
-		# The child test re-sources GIT-BUILD-OPTIONS and may thus
-		# override the test output directory. We thus pass it as an
-		# explicit override to the child.
-		TEST_OUTPUT_DIRECTORY_OVERRIDE=$(pwd) &&
-		export TEST_OUTPUT_DIRECTORY_OVERRIDE &&
-		GIT_SKIP_TESTS=$skip &&
-		export GIT_SKIP_TESTS &&
-		sane_unset GIT_TEST_FAIL_PREREQS &&
-		if test -z "$neg"
-		then
-			./"$name.sh" "$@" >out 2>err
-		else
-			! ./"$name.sh" "$@" >out 2>err
-		fi
-	)
-}
-
-run_sub_test_lib_test () {
-	_run_sub_test_lib_test_common '' "$@"
-}
-
-run_sub_test_lib_test_err () {
-	_run_sub_test_lib_test_common '!' "$@"
-}
-
-check_sub_test_lib_test () {
-	name="$1" # stdin is the expected output from the test
-	(
-		cd "$name" &&
-		test_must_be_empty err &&
-		sed -e 's/^> //' -e 's/Z$//' >expect &&
-		test_cmp expect out
-	)
-}
-
-check_sub_test_lib_test_err () {
-	name="$1" # stdin is the expected output from the test
-	# expected error output is in descriptor 3
-	(
-		cd "$name" &&
-		sed -e 's/^> //' -e 's/Z$//' >expect.out &&
-		test_cmp expect.out out &&
-		sed -e 's/^> //' -e 's/Z$//' <&3 >expect.err &&
-		test_cmp expect.err err
-	)
-}
-
-test_expect_success 'pretend we have a fully passing test suite' '
-	run_sub_test_lib_test full-pass "3 passing tests" <<-\EOF &&
+test_expect_success 'subtest: 3 passing tests' '
+	write_and_run_sub_test_lib_test full-pass <<-\EOF &&
 	for i in 1 2 3
 	do
 		test_expect_success "passing test #$i" "true"
@@ -170,9 +84,8 @@
 	EOF
 '
 
-test_expect_success 'pretend we have a partially passing test suite' '
-	run_sub_test_lib_test_err \
-		partial-pass "2/3 tests passing" <<-\EOF &&
+test_expect_success 'subtest: 2/3 tests passing' '
+	write_and_run_sub_test_lib_test_err partial-pass <<-\EOF &&
 	test_expect_success "passing test #1" "true"
 	test_expect_success "failing test #2" "false"
 	test_expect_success "passing test #3" "true"
@@ -188,8 +101,8 @@
 	EOF
 '
 
-test_expect_success 'pretend we have a known breakage' '
-	run_sub_test_lib_test failing-todo "A failing TODO test" <<-\EOF &&
+test_expect_success 'subtest: a failing TODO test' '
+	write_and_run_sub_test_lib_test failing-todo <<-\EOF &&
 	test_expect_success "passing test" "true"
 	test_expect_failure "pretend we have a known breakage" "false"
 	test_done
@@ -203,8 +116,8 @@
 	EOF
 '
 
-test_expect_success 'pretend we have fixed a known breakage' '
-	run_sub_test_lib_test passing-todo "A passing TODO test" <<-\EOF &&
+test_expect_success 'subtest: a passing TODO test' '
+	write_and_run_sub_test_lib_test passing-todo <<-\EOF &&
 	test_expect_failure "pretend we have fixed a known breakage" "true"
 	test_done
 	EOF
@@ -215,9 +128,8 @@
 	EOF
 '
 
-test_expect_success 'pretend we have fixed one of two known breakages (run in sub test-lib)' '
-	run_sub_test_lib_test partially-passing-todos \
-		"2 TODO tests, one passing" <<-\EOF &&
+test_expect_success 'subtest: 2 TODO tests, one passin' '
+	write_and_run_sub_test_lib_test partially-passing-todos <<-\EOF &&
 	test_expect_failure "pretend we have a known breakage" "false"
 	test_expect_success "pretend we have a passing test" "true"
 	test_expect_failure "pretend we have fixed another known breakage" "true"
@@ -234,9 +146,8 @@
 	EOF
 '
 
-test_expect_success 'pretend we have a pass, fail, and known breakage' '
-	run_sub_test_lib_test_err \
-		mixed-results1 "mixed results #1" <<-\EOF &&
+test_expect_success 'subtest: mixed results: pass, failure and a TODO test' '
+	write_and_run_sub_test_lib_test_err mixed-results1 <<-\EOF &&
 	test_expect_success "passing test" "true"
 	test_expect_success "failing test" "false"
 	test_expect_failure "pretend we have a known breakage" "false"
@@ -253,9 +164,8 @@
 	EOF
 '
 
-test_expect_success 'pretend we have a mix of all possible results' '
-	run_sub_test_lib_test_err \
-		mixed-results2 "mixed results #2" <<-\EOF &&
+test_expect_success 'subtest: mixed results: a mixture of all possible results' '
+	write_and_run_sub_test_lib_test_err mixed-results2 <<-\EOF &&
 	test_expect_success "passing test" "true"
 	test_expect_success "passing test" "true"
 	test_expect_success "passing test" "true"
@@ -289,9 +199,8 @@
 	EOF
 '
 
-test_expect_success 'test --verbose' '
-	run_sub_test_lib_test_err \
-		t1234-verbose "test verbose" --verbose <<-\EOF &&
+test_expect_success 'subtest: --verbose option' '
+	write_and_run_sub_test_lib_test_err t1234-verbose --verbose <<-\EOF &&
 	test_expect_success "passing test" true
 	test_expect_success "test with output" "echo foo"
 	test_expect_success "failing test" false
@@ -316,19 +225,14 @@
 	EOF
 '
 
-test_expect_success 'test --verbose-only' '
+test_expect_success 'subtest: --verbose-only option' '
 	run_sub_test_lib_test_err \
-		t2345-verbose-only-2 "test verbose-only=2" \
-		--verbose-only=2 <<-\EOF &&
-	test_expect_success "passing test" true
-	test_expect_success "test with output" "echo foo"
-	test_expect_success "failing test" false
-	test_done
-	EOF
-	check_sub_test_lib_test t2345-verbose-only-2 <<-\EOF
+		t1234-verbose \
+		--verbose-only=2 &&
+	check_sub_test_lib_test t1234-verbose <<-\EOF
 	> ok 1 - passing test
 	> Z
-	> expecting success of 2345.2 '\''test with output'\'': echo foo
+	> expecting success of 1234.2 '\''test with output'\'': echo foo
 	> foo
 	> ok 2 - test with output
 	> Z
@@ -339,18 +243,11 @@
 	EOF
 '
 
-test_expect_success 'GIT_SKIP_TESTS' '
+test_expect_success 'subtest: skip one with GIT_SKIP_TESTS' '
 	(
-		run_sub_test_lib_test git-skip-tests-basic \
-			"GIT_SKIP_TESTS" \
-			--skip="git.2" <<-\EOF &&
-		for i in 1 2 3
-		do
-			test_expect_success "passing test #$i" "true"
-		done
-		test_done
-		EOF
-		check_sub_test_lib_test git-skip-tests-basic <<-\EOF
+		run_sub_test_lib_test full-pass \
+			--skip="full.2" &&
+		check_sub_test_lib_test full-pass <<-\EOF
 		> ok 1 - passing test #1
 		> ok 2 # skip passing test #2 (GIT_SKIP_TESTS)
 		> ok 3 - passing test #3
@@ -360,10 +257,9 @@
 	)
 '
 
-test_expect_success 'GIT_SKIP_TESTS several tests' '
+test_expect_success 'subtest: skip several with GIT_SKIP_TESTS' '
 	(
-		run_sub_test_lib_test git-skip-tests-several \
-			"GIT_SKIP_TESTS several tests" \
+		write_and_run_sub_test_lib_test git-skip-tests-several \
 			--skip="git.2 git.5" <<-\EOF &&
 		for i in 1 2 3 4 5 6
 		do
@@ -384,18 +280,11 @@
 	)
 '
 
-test_expect_success 'GIT_SKIP_TESTS sh pattern' '
+test_expect_success 'subtest: sh pattern skipping with GIT_SKIP_TESTS' '
 	(
-		run_sub_test_lib_test git-skip-tests-sh-pattern \
-			"GIT_SKIP_TESTS sh pattern" \
-			--skip="git.[2-5]" <<-\EOF &&
-		for i in 1 2 3 4 5 6
-		do
-			test_expect_success "passing test #$i" "true"
-		done
-		test_done
-		EOF
-		check_sub_test_lib_test git-skip-tests-sh-pattern <<-\EOF
+		run_sub_test_lib_test git-skip-tests-several \
+			--skip="git.[2-5]" &&
+		check_sub_test_lib_test git-skip-tests-several <<-\EOF
 		> ok 1 - passing test #1
 		> ok 2 # skip passing test #2 (GIT_SKIP_TESTS)
 		> ok 3 # skip passing test #3 (GIT_SKIP_TESTS)
@@ -408,35 +297,23 @@
 	)
 '
 
-test_expect_success 'GIT_SKIP_TESTS entire suite' '
+test_expect_success 'subtest: skip entire test suite with GIT_SKIP_TESTS' '
 	(
-		run_sub_test_lib_test git-skip-tests-entire-suite \
-			"GIT_SKIP_TESTS entire suite" \
-			--skip="git" <<-\EOF &&
-		for i in 1 2 3
-		do
-			test_expect_success "passing test #$i" "true"
-		done
-		test_done
-		EOF
-		check_sub_test_lib_test git-skip-tests-entire-suite <<-\EOF
+		GIT_SKIP_TESTS="git" && export GIT_SKIP_TESTS &&
+		run_sub_test_lib_test git-skip-tests-several \
+			--skip="git" &&
+		check_sub_test_lib_test git-skip-tests-several <<-\EOF
 		> 1..0 # SKIP skip all tests in git
 		EOF
 	)
 '
 
-test_expect_success 'GIT_SKIP_TESTS does not skip unmatched suite' '
+test_expect_success 'subtest: GIT_SKIP_TESTS does not skip unmatched suite' '
 	(
-		run_sub_test_lib_test git-skip-tests-unmatched-suite \
-			"GIT_SKIP_TESTS does not skip unmatched suite" \
-			--skip="notgit" <<-\EOF &&
-		for i in 1 2 3
-		do
-			test_expect_success "passing test #$i" "true"
-		done
-		test_done
-		EOF
-		check_sub_test_lib_test git-skip-tests-unmatched-suite <<-\EOF
+		GIT_SKIP_TESTS="notgit" && export GIT_SKIP_TESTS &&
+		run_sub_test_lib_test full-pass \
+			--skip="notfull" &&
+		check_sub_test_lib_test full-pass <<-\EOF
 		> ok 1 - passing test #1
 		> ok 2 - passing test #2
 		> ok 3 - passing test #3
@@ -446,16 +323,9 @@
 	)
 '
 
-test_expect_success '--run basic' '
-	run_sub_test_lib_test run-basic \
-		"--run basic" --run="1,3,5" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-basic <<-\EOF
+test_expect_success 'subtest: --run basic' '
+	run_sub_test_lib_test git-skip-tests-several --run="1,3,5" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 - passing test #1
 	> ok 2 # skip passing test #2 (--run)
 	> ok 3 - passing test #3
@@ -467,16 +337,10 @@
 	EOF
 '
 
-test_expect_success '--run with a range' '
-	run_sub_test_lib_test run-range \
-		"--run with a range" --run="1-3" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-range <<-\EOF
+test_expect_success 'subtest: --run with a range' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run="1-3" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 - passing test #1
 	> ok 2 - passing test #2
 	> ok 3 - passing test #3
@@ -488,16 +352,10 @@
 	EOF
 '
 
-test_expect_success '--run with two ranges' '
-	run_sub_test_lib_test run-two-ranges \
-		"--run with two ranges" --run="1-2,5-6" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-two-ranges <<-\EOF
+test_expect_success 'subtest: --run with two ranges' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run="1-2,5-6" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 - passing test #1
 	> ok 2 - passing test #2
 	> ok 3 # skip passing test #3 (--run)
@@ -509,16 +367,10 @@
 	EOF
 '
 
-test_expect_success '--run with a left open range' '
-	run_sub_test_lib_test run-left-open-range \
-		"--run with a left open range" --run="-3" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-left-open-range <<-\EOF
+test_expect_success 'subtest: --run with a left open range' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run="-3" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 - passing test #1
 	> ok 2 - passing test #2
 	> ok 3 - passing test #3
@@ -530,16 +382,10 @@
 	EOF
 '
 
-test_expect_success '--run with a right open range' '
-	run_sub_test_lib_test run-right-open-range \
-		"--run with a right open range" --run="4-" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-right-open-range <<-\EOF
+test_expect_success 'subtest: --run with a right open range' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run="4-" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 # skip passing test #1 (--run)
 	> ok 2 # skip passing test #2 (--run)
 	> ok 3 # skip passing test #3 (--run)
@@ -551,16 +397,10 @@
 	EOF
 '
 
-test_expect_success '--run with basic negation' '
-	run_sub_test_lib_test run-basic-neg \
-		"--run with basic negation" --run="!3" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-basic-neg <<-\EOF
+test_expect_success 'subtest: --run with basic negation' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run="!3" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 - passing test #1
 	> ok 2 - passing test #2
 	> ok 3 # skip passing test #3 (--run)
@@ -572,16 +412,10 @@
 	EOF
 '
 
-test_expect_success '--run with two negations' '
-	run_sub_test_lib_test run-two-neg \
-		"--run with two negations" --run="!3,!6" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-two-neg <<-\EOF
+test_expect_success 'subtest: --run with two negations' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run="!3,!6" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 - passing test #1
 	> ok 2 - passing test #2
 	> ok 3 # skip passing test #3 (--run)
@@ -593,16 +427,10 @@
 	EOF
 '
 
-test_expect_success '--run a range and negation' '
-	run_sub_test_lib_test run-range-and-neg \
-		"--run a range and negation" --run="-4,!2" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-range-and-neg <<-\EOF
+test_expect_success 'subtest: --run a range and negation' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run="-4,!2" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 - passing test #1
 	> ok 2 # skip passing test #2 (--run)
 	> ok 3 - passing test #3
@@ -614,16 +442,10 @@
 	EOF
 '
 
-test_expect_success '--run range negation' '
-	run_sub_test_lib_test run-range-neg \
-		"--run range negation" --run="!1-3" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-range-neg <<-\EOF
+test_expect_success 'subtest: --run range negation' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run="!1-3" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 # skip passing test #1 (--run)
 	> ok 2 # skip passing test #2 (--run)
 	> ok 3 # skip passing test #3 (--run)
@@ -635,17 +457,10 @@
 	EOF
 '
 
-test_expect_success '--run include, exclude and include' '
-	run_sub_test_lib_test run-inc-neg-inc \
-		"--run include, exclude and include" \
-		--run="1-5,!1-3,2" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-inc-neg-inc <<-\EOF
+test_expect_success 'subtest: --run include, exclude and include' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run="1-5,!1-3,2" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 # skip passing test #1 (--run)
 	> ok 2 - passing test #2
 	> ok 3 # skip passing test #3 (--run)
@@ -657,17 +472,10 @@
 	EOF
 '
 
-test_expect_success '--run include, exclude and include, comma separated' '
-	run_sub_test_lib_test run-inc-neg-inc-comma \
-		"--run include, exclude and include, comma separated" \
-		--run=1-5,!1-3,2 <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-inc-neg-inc-comma <<-\EOF
+test_expect_success 'subtest: --run include, exclude and include, comma separated' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run=1-5,!1-3,2 &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 # skip passing test #1 (--run)
 	> ok 2 - passing test #2
 	> ok 3 # skip passing test #3 (--run)
@@ -679,17 +487,10 @@
 	EOF
 '
 
-test_expect_success '--run exclude and include' '
-	run_sub_test_lib_test run-neg-inc \
-		"--run exclude and include" \
-		--run="!3-,5" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-neg-inc <<-\EOF
+test_expect_success 'subtest: --run exclude and include' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run="!3-,5" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 - passing test #1
 	> ok 2 - passing test #2
 	> ok 3 # skip passing test #3 (--run)
@@ -701,17 +502,10 @@
 	EOF
 '
 
-test_expect_success '--run empty selectors' '
-	run_sub_test_lib_test run-empty-sel \
-		"--run empty selectors" \
-		--run="1,,3,,,5" <<-\EOF &&
-	for i in 1 2 3 4 5 6
-	do
-		test_expect_success "passing test #$i" "true"
-	done
-	test_done
-	EOF
-	check_sub_test_lib_test run-empty-sel <<-\EOF
+test_expect_success 'subtest: --run empty selectors' '
+	run_sub_test_lib_test git-skip-tests-several \
+		--run="1,,3,,,5" &&
+	check_sub_test_lib_test git-skip-tests-several <<-\EOF
 	> ok 1 - passing test #1
 	> ok 2 # skip passing test #2 (--run)
 	> ok 3 - passing test #3
@@ -723,9 +517,8 @@
 	EOF
 '
 
-test_expect_success '--run substring selector' '
-	run_sub_test_lib_test run-substring-selector \
-		"--run empty selectors" \
+test_expect_success 'subtest: --run substring selector' '
+	write_and_run_sub_test_lib_test run-substring-selector \
 		--run="relevant" <<-\EOF &&
 	test_expect_success "relevant test" "true"
 	for i in 1 2 3 4 5 6
@@ -747,9 +540,8 @@
 	EOF
 '
 
-test_expect_success '--run keyword selection' '
-	run_sub_test_lib_test_err run-inv-range-start \
-		"--run invalid range start" \
+test_expect_success 'subtest: --run keyword selection' '
+	write_and_run_sub_test_lib_test_err run-inv-range-start \
 		--run="a-5" <<-\EOF &&
 	test_expect_success "passing test #1" "true"
 	test_done
@@ -762,14 +554,10 @@
 	EOF_ERR
 '
 
-test_expect_success '--run invalid range end' '
-	run_sub_test_lib_test_err run-inv-range-end \
-		"--run invalid range end" \
-		--run="1-z" <<-\EOF &&
-	test_expect_success "passing test #1" "true"
-	test_done
-	EOF
-	check_sub_test_lib_test_err run-inv-range-end \
+test_expect_success 'subtest: --run invalid range end' '
+	run_sub_test_lib_test_err run-inv-range-start \
+		--run="1-z" &&
+	check_sub_test_lib_test_err run-inv-range-start \
 		<<-\EOF_OUT 3<<-EOF_ERR
 	> FATAL: Unexpected exit with code 1
 	EOF_OUT
@@ -777,8 +565,8 @@
 	EOF_ERR
 '
 
-test_expect_success 'tests respect prerequisites' '
-	run_sub_test_lib_test prereqs "tests respect prereqs" <<-\EOF &&
+test_expect_success 'subtest: tests respect prerequisites' '
+	write_and_run_sub_test_lib_test prereqs <<-\EOF &&
 
 	test_set_prereq HAVEIT
 	test_expect_success HAVEIT "prereq is satisfied" "true"
@@ -807,8 +595,8 @@
 	EOF
 '
 
-test_expect_success 'tests respect lazy prerequisites' '
-	run_sub_test_lib_test lazy-prereqs "respect lazy prereqs" <<-\EOF &&
+test_expect_success 'subtest: tests respect lazy prerequisites' '
+	write_and_run_sub_test_lib_test lazy-prereqs <<-\EOF &&
 
 	test_lazy_prereq LAZY_TRUE true
 	test_expect_success LAZY_TRUE "lazy prereq is satisifed" "true"
@@ -831,8 +619,8 @@
 	EOF
 '
 
-test_expect_success 'nested lazy prerequisites' '
-	run_sub_test_lib_test nested-lazy "nested lazy prereqs" <<-\EOF &&
+test_expect_success 'subtest: nested lazy prerequisites' '
+	write_and_run_sub_test_lib_test nested-lazy <<-\EOF &&
 
 	test_lazy_prereq NESTED_INNER "
 		>inner &&
@@ -857,9 +645,9 @@
 	EOF
 '
 
-test_expect_success 'lazy prereqs do not turn off tracing' '
-	run_sub_test_lib_test lazy-prereq-and-tracing \
-		"lazy prereqs and -x" -v -x <<-\EOF &&
+test_expect_success 'subtest: lazy prereqs do not turn off tracing' '
+	write_and_run_sub_test_lib_test lazy-prereq-and-tracing \
+		-v -x <<-\EOF &&
 	test_lazy_prereq LAZY true
 
 	test_expect_success lazy "test_have_prereq LAZY && echo trace"
@@ -870,8 +658,8 @@
 	grep "echo trace" lazy-prereq-and-tracing/err
 '
 
-test_expect_success 'tests clean up after themselves' '
-	run_sub_test_lib_test cleanup "test with cleanup" <<-\EOF &&
+test_expect_success 'subtest: tests clean up after themselves' '
+	write_and_run_sub_test_lib_test cleanup <<-\EOF &&
 	clean=no
 	test_expect_success "do cleanup" "
 		test_when_finished clean=yes
@@ -890,9 +678,9 @@
 	EOF
 '
 
-test_expect_success 'tests clean up even on failures' '
-	run_sub_test_lib_test_err \
-		failing-cleanup "Failing tests with cleanup commands" <<-\EOF &&
+test_expect_success 'subtest: tests clean up even on failures' '
+	write_and_run_sub_test_lib_test_err \
+		failing-cleanup <<-\EOF &&
 	test_expect_success "tests clean up even after a failure" "
 		touch clean-after-failure &&
 		test_when_finished rm clean-after-failure &&
@@ -919,9 +707,9 @@
 	EOF
 '
 
-test_expect_success 'test_atexit is run' '
-	run_sub_test_lib_test_err \
-		atexit-cleanup "Run atexit commands" -i <<-\EOF &&
+test_expect_success 'subtest: test_atexit is run' '
+	write_and_run_sub_test_lib_test_err \
+		atexit-cleanup -i <<-\EOF &&
 	test_expect_success "tests clean up even after a failure" "
 		> ../../clean-atexit &&
 		test_atexit rm ../../clean-atexit &&
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index df544bb..7603ad2 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -2,6 +2,7 @@
 
 test_description='git init'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 check_config () {
diff --git a/t/t0002-gitfile.sh b/t/t0002-gitfile.sh
index 8440e6a..76052cb 100755
--- a/t/t0002-gitfile.sh
+++ b/t/t0002-gitfile.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
 
 objpath() {
diff --git a/t/t0003-attributes.sh b/t/t0003-attributes.sh
index 1e4c672..b9ed612 100755
--- a/t/t0003-attributes.sh
+++ b/t/t0003-attributes.sh
@@ -2,6 +2,7 @@
 
 test_description=gitattributes
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 attr_check_basic () {
diff --git a/t/t0004-unwritable.sh b/t/t0004-unwritable.sh
index e3137d6..2e9d652 100755
--- a/t/t0004-unwritable.sh
+++ b/t/t0004-unwritable.sh
@@ -2,6 +2,7 @@
 
 test_description='detect unwritable repository and fail correctly'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
@@ -18,27 +19,66 @@
 test_expect_success POSIXPERM,SANITY 'write-tree should notice unwritable repository' '
 	test_when_finished "chmod 775 .git/objects .git/objects/??" &&
 	chmod a-w .git/objects .git/objects/?? &&
-	test_must_fail git write-tree
+	test_must_fail git write-tree 2>out.write-tree
 '
 
-test_expect_success POSIXPERM,SANITY 'commit should notice unwritable repository' '
+test_lazy_prereq WRITE_TREE_OUT 'test -e "$TRASH_DIRECTORY"/out.write-tree'
+test_expect_success WRITE_TREE_OUT 'write-tree output on unwritable repository' '
+	cat >expect <<-\EOF &&
+	error: insufficient permission for adding an object to repository database .git/objects
+	fatal: git-write-tree: error building trees
+	EOF
+	test_cmp expect out.write-tree
+'
+
+test_expect_success POSIXPERM,SANITY,!SANITIZE_LEAK 'commit should notice unwritable repository' '
 	test_when_finished "chmod 775 .git/objects .git/objects/??" &&
 	chmod a-w .git/objects .git/objects/?? &&
-	test_must_fail git commit -m second
+	test_must_fail git commit -m second 2>out.commit
+'
+
+test_lazy_prereq COMMIT_OUT 'test -e "$TRASH_DIRECTORY"/out.commit'
+test_expect_success COMMIT_OUT 'commit output on unwritable repository' '
+	cat >expect <<-\EOF &&
+	error: insufficient permission for adding an object to repository database .git/objects
+	error: Error building trees
+	EOF
+	test_cmp expect out.commit
 '
 
 test_expect_success POSIXPERM,SANITY 'update-index should notice unwritable repository' '
 	test_when_finished "chmod 775 .git/objects .git/objects/??" &&
 	echo 6O >file &&
 	chmod a-w .git/objects .git/objects/?? &&
-	test_must_fail git update-index file
+	test_must_fail git update-index file 2>out.update-index
+'
+
+test_lazy_prereq UPDATE_INDEX_OUT 'test -e "$TRASH_DIRECTORY"/out.update-index'
+test_expect_success UPDATE_INDEX_OUT 'update-index output on unwritable repository' '
+	cat >expect <<-\EOF &&
+	error: insufficient permission for adding an object to repository database .git/objects
+	error: file: failed to insert into database
+	fatal: Unable to process path file
+	EOF
+	test_cmp expect out.update-index
 '
 
 test_expect_success POSIXPERM,SANITY 'add should notice unwritable repository' '
 	test_when_finished "chmod 775 .git/objects .git/objects/??" &&
 	echo b >file &&
 	chmod a-w .git/objects .git/objects/?? &&
-	test_must_fail git add file
+	test_must_fail git add file 2>out.add
+'
+
+test_lazy_prereq ADD_OUT 'test -e "$TRASH_DIRECTORY"/out.add'
+test_expect_success ADD_OUT 'add output on unwritable repository' '
+	cat >expect <<-\EOF &&
+	error: insufficient permission for adding an object to repository database .git/objects
+	error: file: failed to insert into database
+	error: unable to index file '\''file'\''
+	fatal: updating files failed
+	EOF
+	test_cmp expect out.add
 '
 
 test_done
diff --git a/t/t0005-signals.sh b/t/t0005-signals.sh
index 4c214bd..a5ec6a0 100755
--- a/t/t0005-signals.sh
+++ b/t/t0005-signals.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='signals work as we expect'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 cat >expect <<EOF
diff --git a/t/t0007-git-var.sh b/t/t0007-git-var.sh
index 88b9ae8..53af92d 100755
--- a/t/t0007-git-var.sh
+++ b/t/t0007-git-var.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='basic sanity checks for git var'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'get GIT_AUTHOR_IDENT' '
diff --git a/t/t0008-ignores.sh b/t/t0008-ignores.sh
index a594b4a..532637d 100755
--- a/t/t0008-ignores.sh
+++ b/t/t0008-ignores.sh
@@ -2,6 +2,7 @@
 
 test_description=check-ignore
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 init_vars () {
diff --git a/t/t0009-prio-queue.sh b/t/t0009-prio-queue.sh
index 3941ad2..eea9910 100755
--- a/t/t0009-prio-queue.sh
+++ b/t/t0009-prio-queue.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='basic tests for priority queue implementation'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 cat >expect <<'EOF'
diff --git a/t/t0010-racy-git.sh b/t/t0010-racy-git.sh
index 5657c5a..837c8b7 100755
--- a/t/t0010-racy-git.sh
+++ b/t/t0010-racy-git.sh
@@ -2,6 +2,7 @@
 
 test_description='racy GIT'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # This test can give false success if your machine is sufficiently
diff --git a/t/t0011-hashmap.sh b/t/t0011-hashmap.sh
index 5343ffd..e094975 100755
--- a/t/t0011-hashmap.sh
+++ b/t/t0011-hashmap.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test hashmap and string hash functions'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_hashmap() {
diff --git a/t/t0012-help.sh b/t/t0012-help.sh
index 5679e29..91b68c7 100755
--- a/t/t0012-help.sh
+++ b/t/t0012-help.sh
@@ -34,6 +34,18 @@
 	git help -a >/dev/null
 '
 
+test_expect_success 'invalid usage' '
+	test_expect_code 129 git help -g add &&
+	test_expect_code 129 git help -a -c &&
+
+	test_expect_code 129 git help -g add &&
+	test_expect_code 129 git help -a -g &&
+
+	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
+'
+
 test_expect_success "works for commands and guides by default" '
 	configure_help &&
 	git help status &&
@@ -73,6 +85,59 @@
 	test_i18ngrep "^   tutorial   " help.output
 '
 
+test_expect_success 'git help fails for non-existing html pages' '
+	configure_help &&
+	mkdir html-empty &&
+	test_must_fail git -c help.htmlpath=html-empty help status &&
+	test_must_be_empty test-browser.log
+'
+
+test_expect_success 'git help succeeds without git.html' '
+	configure_help &&
+	mkdir html-with-docs &&
+	touch html-with-docs/git-status.html &&
+	git -c help.htmlpath=html-with-docs help status &&
+	echo "html-with-docs/git-status.html" >expect &&
+	test_cmp expect test-browser.log
+'
+
+test_expect_success 'git help -c' '
+	git help -c >help.output &&
+	cat >expect <<-\EOF &&
+
+	'\''git help config'\'' for more information
+	EOF
+	grep -v -E \
+		-e "^[^.]+\.[^.]+$" \
+		-e "^[^.]+\.[^.]+\.[^.]+$" \
+		help.output >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'git help --config-for-completion' '
+	git help -c >human &&
+	grep -E \
+	     -e "^[^.]+\.[^.]+$" \
+	     -e "^[^.]+\.[^.]+\.[^.]+$" human |
+	     sed -e "s/\*.*//" -e "s/<.*//" |
+	     sort -u >human.munged &&
+
+	git help --config-for-completion >vars &&
+	test_cmp human.munged vars
+'
+
+test_expect_success 'git help --config-sections-for-completion' '
+	git help -c >human &&
+	grep -E \
+	     -e "^[^.]+\.[^.]+$" \
+	     -e "^[^.]+\.[^.]+\.[^.]+$" human |
+	     sed -e "s/\..*//" |
+	     sort -u >human.munged &&
+
+	git help --config-sections-for-completion >sections &&
+	test_cmp human.munged sections
+'
+
 test_expect_success 'generate builtin list' '
 	git --list-cmds=builtins >builtins
 '
diff --git a/t/t0013-sha1dc.sh b/t/t0013-sha1dc.sh
index 419f31a..9ad7608 100755
--- a/t/t0013-sha1dc.sh
+++ b/t/t0013-sha1dc.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test sha1 collision detection'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 TEST_DATA="$TEST_DIRECTORY/t0013"
 
diff --git a/t/t0016-oidmap.sh b/t/t0016-oidmap.sh
index 31f8276..0faef1f 100755
--- a/t/t0016-oidmap.sh
+++ b/t/t0016-oidmap.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test oidmap'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # This purposefully is very similar to t0011-hashmap.sh
diff --git a/t/t0017-env-helper.sh b/t/t0017-env-helper.sh
index 4a159f9..2e42fba 100755
--- a/t/t0017-env-helper.sh
+++ b/t/t0017-env-helper.sh
@@ -2,6 +2,7 @@
 
 test_description='test env--helper'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 
diff --git a/t/t0018-advice.sh b/t/t0018-advice.sh
index 39e5e4b..c13057a 100755
--- a/t/t0018-advice.sh
+++ b/t/t0018-advice.sh
@@ -2,6 +2,7 @@
 
 test_description='Test advise_if_enabled functionality'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'advice should be printed when config variable is unset' '
diff --git a/t/t0022-crlf-rename.sh b/t/t0022-crlf-rename.sh
index 7af3fbc..c1a331e 100755
--- a/t/t0022-crlf-rename.sh
+++ b/t/t0022-crlf-rename.sh
@@ -2,6 +2,7 @@
 
 test_description='ignore CR in CRLF sequence while computing similiarity'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t0024-crlf-archive.sh b/t/t0024-crlf-archive.sh
index 4e9fa3c..a34de56 100755
--- a/t/t0024-crlf-archive.sh
+++ b/t/t0024-crlf-archive.sh
@@ -2,6 +2,7 @@
 
 test_description='respect crlf in git archive'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t0025-crlf-renormalize.sh b/t/t0025-crlf-renormalize.sh
index e13363a..8144797 100755
--- a/t/t0025-crlf-renormalize.sh
+++ b/t/t0025-crlf-renormalize.sh
@@ -2,6 +2,7 @@
 
 test_description='CRLF renormalization'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t0026-eol-config.sh b/t/t0026-eol-config.sh
index c5203e2..cdcafcd 100755
--- a/t/t0026-eol-config.sh
+++ b/t/t0026-eol-config.sh
@@ -2,6 +2,7 @@
 
 test_description='CRLF conversion'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 has_cr() {
diff --git a/t/t0029-core-unsetenvvars.sh b/t/t0029-core-unsetenvvars.sh
index 24ce46a..b138e1d 100755
--- a/t/t0029-core-unsetenvvars.sh
+++ b/t/t0029-core-unsetenvvars.sh
@@ -2,6 +2,7 @@
 
 test_description='test the Windows-only core.unsetenvvars setting'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 if ! test_have_prereq MINGW
diff --git a/t/t0030-stripspace.sh b/t/t0030-stripspace.sh
index 0c24a0f..ae1ca38 100755
--- a/t/t0030-stripspace.sh
+++ b/t/t0030-stripspace.sh
@@ -5,6 +5,7 @@
 
 test_description='git stripspace'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 t40='A quick brown fox jumps over the lazy do'
diff --git a/t/t0040-parse-options.sh b/t/t0040-parse-options.sh
index ad4746d..ed2fb62 100755
--- a/t/t0040-parse-options.sh
+++ b/t/t0040-parse-options.sh
@@ -5,6 +5,7 @@
 
 test_description='our own option parser'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 cat >expect <<\EOF
@@ -37,7 +38,6 @@
     --list <str>          add str to list
 
 Magic arguments
-    --quux                means --quux
     -NUM                  set integer to NUM
     +                     same as -b
     --ambiguous           positive ambiguity
@@ -169,9 +169,45 @@
 '
 
 test_expect_success 'missing required value' '
-	test_expect_code 129 test-tool parse-options -s &&
-	test_expect_code 129 test-tool parse-options --string &&
-	test_expect_code 129 test-tool parse-options --file
+	cat >expect <<-\EOF &&
+	error: switch `s'\'' requires a value
+	EOF
+	test_expect_code 129 test-tool parse-options -s 2>actual &&
+	test_cmp expect actual &&
+
+	cat >expect <<-\EOF &&
+	error: option `string'\'' requires a value
+	EOF
+	test_expect_code 129 test-tool parse-options --string 2>actual &&
+	test_cmp expect actual &&
+
+	cat >expect <<-\EOF &&
+	error: option `file'\'' requires a value
+	EOF
+	test_expect_code 129 test-tool parse-options --file 2>actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'superfluous value provided: boolean' '
+	cat >expect <<-\EOF &&
+	error: option `yes'\'' takes no value
+	EOF
+	test_expect_code 129 test-tool parse-options --yes=hi 2>actual &&
+	test_cmp expect actual &&
+
+	cat >expect <<-\EOF &&
+	error: option `no-yes'\'' takes no value
+	EOF
+	test_expect_code 129 test-tool parse-options --no-yes=hi 2>actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'superfluous value provided: cmdmode' '
+	cat >expect <<-\EOF &&
+	error: option `mode1'\'' takes no value
+	EOF
+	test_expect_code 129 test-tool parse-options --mode1=hi 2>actual &&
+	test_cmp expect actual
 '
 
 cat >expect <<\EOF
@@ -263,10 +299,6 @@
 	test_cmp typo.err output.err
 '
 
-test_expect_success 'keep some options as arguments' '
-	test-tool parse-options --expect="arg 00: --quux" --quux
-'
-
 cat >expect <<\EOF
 Callback: "four", 0
 boolean: 5
diff --git a/t/t0052-simple-ipc.sh b/t/t0052-simple-ipc.sh
index ff98be3..1a36a53 100755
--- a/t/t0052-simple-ipc.sh
+++ b/t/t0052-simple-ipc.sh
@@ -2,6 +2,7 @@
 
 test_description='simple command server'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test-tool simple-ipc SUPPORTS_SIMPLE_IPC || {
diff --git a/t/t0055-beyond-symlinks.sh b/t/t0055-beyond-symlinks.sh
index 0c6ff56..6bada37 100755
--- a/t/t0055-beyond-symlinks.sh
+++ b/t/t0055-beyond-symlinks.sh
@@ -2,6 +2,7 @@
 
 test_description='update-index and add refuse to add beyond symlinks'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success SYMLINKS setup '
diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
index de49607..34d1061 100755
--- a/t/t0060-path-utils.sh
+++ b/t/t0060-path-utils.sh
@@ -525,4 +525,30 @@
 		"PRN./abc"
 '
 
+test_lazy_prereq RUNTIME_PREFIX '
+	test true = "$RUNTIME_PREFIX"
+'
+
+test_lazy_prereq CAN_EXEC_IN_PWD '
+	cp "$GIT_EXEC_PATH"/git$X ./ &&
+	./git rev-parse
+'
+
+test_expect_success RUNTIME_PREFIX,CAN_EXEC_IN_PWD 'RUNTIME_PREFIX works' '
+	mkdir -p pretend/bin pretend/libexec/git-core &&
+	echo "echo HERE" | write_script pretend/libexec/git-core/git-here &&
+	cp "$GIT_EXEC_PATH"/git$X pretend/bin/ &&
+	GIT_EXEC_PATH= ./pretend/bin/git here >actual &&
+	echo HERE >expect &&
+	test_cmp expect actual'
+
+test_expect_success RUNTIME_PREFIX,CAN_EXEC_IN_PWD '%(prefix)/ works' '
+	mkdir -p pretend/bin &&
+	cp "$GIT_EXEC_PATH"/git$X pretend/bin/ &&
+	git config yes.path "%(prefix)/yes" &&
+	GIT_EXEC_PATH= ./pretend/bin/git config --path yes.path >actual &&
+	echo "$(pwd)/pretend/yes" >expect &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t0061-run-command.sh b/t/t0061-run-command.sh
index 7d59967..ee28190 100755
--- a/t/t0061-run-command.sh
+++ b/t/t0061-run-command.sh
@@ -5,6 +5,7 @@
 
 test_description='Test run command'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 cat >hello-script <<-EOF
diff --git a/t/t0063-string-list.sh b/t/t0063-string-list.sh
index c6ee9f6..46d4839 100755
--- a/t/t0063-string-list.sh
+++ b/t/t0063-string-list.sh
@@ -5,6 +5,7 @@
 
 test_description='Test string list functionality'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_split () {
diff --git a/t/t0064-oid-array.sh b/t/t0064-oid-array.sh
index 2e5438c..88c89e8 100755
--- a/t/t0064-oid-array.sh
+++ b/t/t0064-oid-array.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='basic tests for the oid array implementation'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 echoid () {
diff --git a/t/t0065-strcmp-offset.sh b/t/t0065-strcmp-offset.sh
index 91fa639..94e34c8 100755
--- a/t/t0065-strcmp-offset.sh
+++ b/t/t0065-strcmp-offset.sh
@@ -2,6 +2,7 @@
 
 test_description='Test strcmp_offset functionality'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 while read s1 s2 expect
diff --git a/t/t0066-dir-iterator.sh b/t/t0066-dir-iterator.sh
index 92910e4..63a1a45 100755
--- a/t/t0066-dir-iterator.sh
+++ b/t/t0066-dir-iterator.sh
@@ -2,6 +2,7 @@
 
 test_description='Test the dir-iterator functionality'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t0067-parse_pathspec_file.sh b/t/t0067-parse_pathspec_file.sh
index 7bab49f..0188d04 100755
--- a/t/t0067-parse_pathspec_file.sh
+++ b/t/t0067-parse_pathspec_file.sh
@@ -2,6 +2,7 @@
 
 test_description='Test parse_pathspec_file()'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'one item from stdin' '
diff --git a/t/t0069-oidtree.sh b/t/t0069-oidtree.sh
index bfb1397..74cc59b 100755
--- a/t/t0069-oidtree.sh
+++ b/t/t0069-oidtree.sh
@@ -1,6 +1,7 @@
 #!/bin/sh
 
 test_description='basic tests for the oidtree implementation'
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 maxhexsz=$(test_oid hexsz)
diff --git a/t/t0071-sort.sh b/t/t0071-sort.sh
new file mode 100755
index 0000000..a8ab174
--- /dev/null
+++ b/t/t0071-sort.sh
@@ -0,0 +1,11 @@
+#!/bin/sh
+
+test_description='verify sort functions'
+
+. ./test-lib.sh
+
+test_expect_success 'llist_mergesort()' '
+	test-tool mergesort test
+'
+
+test_done
diff --git a/t/t0090-cache-tree.sh b/t/t0090-cache-tree.sh
index 9bf66c9..9067572 100755
--- a/t/t0090-cache-tree.sh
+++ b/t/t0090-cache-tree.sh
@@ -195,6 +195,7 @@
 
 test_expect_success 'reset --hard without index gives cache-tree' '
 	rm -f .git/index &&
+	git clean -fd &&
 	git reset --hard &&
 	test_cache_tree
 '
diff --git a/t/t0091-bugreport.sh b/t/t0091-bugreport.sh
index 526304f..eeedbfa 100755
--- a/t/t0091-bugreport.sh
+++ b/t/t0091-bugreport.sh
@@ -2,6 +2,7 @@
 
 test_description='git bugreport'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # Headers "[System Info]" will be followed by a non-empty line if we put some
diff --git a/t/t0210-trace2-normal.sh b/t/t0210-trace2-normal.sh
index 0cf3a63..37c359b 100755
--- a/t/t0210-trace2-normal.sh
+++ b/t/t0210-trace2-normal.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test trace2 facility (normal target)'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # Turn off any inherited trace2 settings for this test.
diff --git a/t/t0210/scrub_normal.perl b/t/t0210/scrub_normal.perl
index c65d1a8..7cc4de3 100644
--- a/t/t0210/scrub_normal.perl
+++ b/t/t0210/scrub_normal.perl
@@ -42,6 +42,12 @@
 	# so just omit it for testing purposes.
 	# print "cmd_path _EXE_\n";
     }
+    elsif ($line =~ m/^cmd_ancestry/) {
+	# 'cmd_ancestry' is not implemented everywhere, so for portability's
+	# sake, skip it when parsing normal.
+	#
+	# print "$line";
+    }
     else {
 	print "$line";
     }
diff --git a/t/t0211-trace2-perf.sh b/t/t0211-trace2-perf.sh
index 6ee8ee3..22d0845 100755
--- a/t/t0211-trace2-perf.sh
+++ b/t/t0211-trace2-perf.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test trace2 facility (perf target)'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # Turn off any inherited trace2 settings for this test.
diff --git a/t/t0211/scrub_perf.perl b/t/t0211/scrub_perf.perl
index 351af78..d164b750 100644
--- a/t/t0211/scrub_perf.perl
+++ b/t/t0211/scrub_perf.perl
@@ -44,6 +44,11 @@
 	# $tokens[$col_rest] = "_EXE_";
 	goto SKIP_LINE;
     }
+    elsif ($tokens[$col_event] =~ m/cmd_ancestry/) {
+	# 'cmd_ancestry' is platform-specific and not implemented everywhere,
+	# so skip it.
+	goto SKIP_LINE;
+    }
     elsif ($tokens[$col_event] =~ m/child_exit/) {
 	$tokens[$col_rest] =~ s/ pid:\d* / pid:_PID_ /;
     }
diff --git a/t/t0212-trace2-event.sh b/t/t0212-trace2-event.sh
index 1529155..6d3374f 100755
--- a/t/t0212-trace2-event.sh
+++ b/t/t0212-trace2-event.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test trace2 facility'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # Turn off any inherited trace2 settings for this test.
diff --git a/t/t0212/parse_events.perl b/t/t0212/parse_events.perl
index 6584bb5..b640856 100644
--- a/t/t0212/parse_events.perl
+++ b/t/t0212/parse_events.perl
@@ -132,7 +132,10 @@
 	# just omit it for testing purposes.
 	# $processes->{$sid}->{'path'} = "_EXE_";
     }
-    
+    elsif ($event eq 'cmd_ancestry') {
+	# 'cmd_ancestry' is platform-specific and not implemented everywhere, so
+	# just skip it for testing purposes.
+    }
     elsif ($event eq 'cmd_name') {
 	$processes->{$sid}->{'name'} = $line->{'name'};
 	$processes->{$sid}->{'hierarchy'} = $line->{'hierarchy'};
diff --git a/t/t0301-credential-cache.sh b/t/t0301-credential-cache.sh
index ebd5fa5..698b715 100755
--- a/t/t0301-credential-cache.sh
+++ b/t/t0301-credential-cache.sh
@@ -9,6 +9,21 @@
 	test_done
 }
 
+uname_s=$(uname -s)
+case $uname_s in
+*MINGW*)
+	test_path_is_socket () {
+		# `test -S` cannot detect Win10's Unix sockets
+		test_path_exists "$1"
+	}
+	;;
+*)
+	test_path_is_socket () {
+		test -S "$1"
+	}
+	;;
+esac
+
 # don't leave a stale daemon running
 test_atexit 'git credential-cache exit'
 
@@ -21,7 +36,7 @@
 		rmdir -p .cache/git/credential/
 	" &&
 	test_path_is_missing "$HOME/.git-credential-cache" &&
-	test -S "$HOME/.cache/git/credential/socket"
+	test_path_is_socket "$HOME/.cache/git/credential/socket"
 '
 
 XDG_CACHE_HOME="$HOME/xdg"
@@ -31,7 +46,7 @@
 
 test_expect_success "use custom XDG_CACHE_HOME if set and default sockets are not created" '
 	test_when_finished "git credential-cache exit" &&
-	test -S "$XDG_CACHE_HOME/git/credential/socket" &&
+	test_path_is_socket "$XDG_CACHE_HOME/git/credential/socket" &&
 	test_path_is_missing "$HOME/.git-credential-cache/socket" &&
 	test_path_is_missing "$HOME/.cache/git/credential/socket"
 '
@@ -48,7 +63,7 @@
 	username=store-user
 	password=store-pass
 	EOF
-	test -S "$HOME/dir/socket"
+	test_path_is_socket "$HOME/dir/socket"
 '
 
 test_expect_success "use custom XDG_CACHE_HOME even if xdg socket exists" '
@@ -62,7 +77,7 @@
 	username=store-user
 	password=store-pass
 	EOF
-	test -S "$HOME/.cache/git/credential/socket" &&
+	test_path_is_socket "$HOME/.cache/git/credential/socket" &&
 	XDG_CACHE_HOME="$HOME/xdg" &&
 	export XDG_CACHE_HOME &&
 	check approve cache <<-\EOF &&
@@ -71,7 +86,7 @@
 	username=store-user
 	password=store-pass
 	EOF
-	test -S "$XDG_CACHE_HOME/git/credential/socket"
+	test_path_is_socket "$XDG_CACHE_HOME/git/credential/socket"
 '
 
 test_expect_success 'use user socket if user directory exists' '
@@ -79,14 +94,15 @@
 		git credential-cache exit &&
 		rmdir \"\$HOME/.git-credential-cache/\"
 	" &&
-	mkdir -p -m 700 "$HOME/.git-credential-cache/" &&
+	mkdir -p "$HOME/.git-credential-cache/" &&
+	chmod 700 "$HOME/.git-credential-cache/" &&
 	check approve cache <<-\EOF &&
 	protocol=https
 	host=example.com
 	username=store-user
 	password=store-pass
 	EOF
-	test -S "$HOME/.git-credential-cache/socket"
+	test_path_is_socket "$HOME/.git-credential-cache/socket"
 '
 
 test_expect_success SYMLINKS 'use user socket if user directory is a symlink to a directory' '
@@ -103,7 +119,7 @@
 	username=store-user
 	password=store-pass
 	EOF
-	test -S "$HOME/.git-credential-cache/socket"
+	test_path_is_socket "$HOME/.git-credential-cache/socket"
 '
 
 helper_test_timeout cache --timeout=1
diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh
index a211a66..bba6796 100755
--- a/t/t0410-partial-clone.sh
+++ b/t/t0410-partial-clone.sh
@@ -4,6 +4,9 @@
 
 . ./test-lib.sh
 
+# missing promisor objects cause repacks which write bitmaps to fail
+GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0
+
 delete_object () {
 	rm $1/.git/objects/$(echo $2 | sed -e 's|^..|&/|')
 }
@@ -536,7 +539,13 @@
 repack_and_check () {
 	rm -rf repo2 &&
 	cp -r repo repo2 &&
-	git -C repo2 repack $1 -d &&
+	if test x"$1" = "x--must-fail"
+	then
+		shift
+		test_must_fail git -C repo2 repack $1 -d
+	else
+		git -C repo2 repack $1 -d
+	fi &&
 	git -C repo2 fsck &&
 
 	git -C repo2 cat-file -e $2 &&
@@ -561,6 +570,7 @@
 	printf "$THREE\n" | pack_as_from_promisor &&
 	delete_object repo "$ONE" &&
 
+	repack_and_check --must-fail -ab "$TWO" "$THREE" &&
 	repack_and_check -a "$TWO" "$THREE" &&
 	repack_and_check -A "$TWO" "$THREE" &&
 	repack_and_check -l "$TWO" "$THREE"
diff --git a/t/t1000-read-tree-m-3way.sh b/t/t1000-read-tree-m-3way.sh
index 013c5a7..0e8c0df 100755
--- a/t/t1000-read-tree-m-3way.sh
+++ b/t/t1000-read-tree-m-3way.sh
@@ -71,6 +71,8 @@
  DF: a special case, where A makes a directory and B makes a file.
 
 '
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-read-tree.sh
 . "$TEST_DIRECTORY"/lib-read-tree-m-3way.sh
diff --git a/t/t1001-read-tree-m-2way.sh b/t/t1001-read-tree-m-2way.sh
index 1057a96..d111552 100755
--- a/t/t1001-read-tree-m-2way.sh
+++ b/t/t1001-read-tree-m-2way.sh
@@ -20,6 +20,8 @@
 	rezrov  - in H, deleted in M
 	yomin   - not in H or M
 '
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-read-tree.sh
 
diff --git a/t/t1003-read-tree-prefix.sh b/t/t1003-read-tree-prefix.sh
index b6111cd..e0db206 100755
--- a/t/t1003-read-tree-prefix.sh
+++ b/t/t1003-read-tree-prefix.sh
@@ -6,6 +6,7 @@
 test_description='git read-tree --prefix test.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t1006-cat-file.sh b/t/t1006-cat-file.sh
index 18b3779..6586283 100755
--- a/t/t1006-cat-file.sh
+++ b/t/t1006-cat-file.sh
@@ -315,39 +315,238 @@
 	}
 '
 
-bogus_type="bogus"
-bogus_content="bogus"
-bogus_size=$(strlen "$bogus_content")
-bogus_sha1=$(echo_without_newline "$bogus_content" | git hash-object -t $bogus_type --literally -w --stdin)
+test_expect_success 'setup bogus data' '
+	bogus_short_type="bogus" &&
+	bogus_short_content="bogus" &&
+	bogus_short_size=$(strlen "$bogus_short_content") &&
+	bogus_short_sha1=$(echo_without_newline "$bogus_short_content" | git hash-object -t $bogus_short_type --literally -w --stdin) &&
+
+	bogus_long_type="abcdefghijklmnopqrstuvwxyz1234679" &&
+	bogus_long_content="bogus" &&
+	bogus_long_size=$(strlen "$bogus_long_content") &&
+	bogus_long_sha1=$(echo_without_newline "$bogus_long_content" | git hash-object -t $bogus_long_type --literally -w --stdin)
+'
+
+for arg1 in '' --allow-unknown-type
+do
+	for arg2 in -s -t -p
+	do
+		if test "$arg1" = "--allow-unknown-type" && test "$arg2" = "-p"
+		then
+			continue
+		fi
+
+
+		test_expect_success "cat-file $arg1 $arg2 error on bogus short OID" '
+			cat >expect <<-\EOF &&
+			fatal: invalid object type
+			EOF
+
+			if test "$arg1" = "--allow-unknown-type"
+			then
+				git cat-file $arg1 $arg2 $bogus_short_sha1
+			else
+				test_must_fail git cat-file $arg1 $arg2 $bogus_short_sha1 >out 2>actual &&
+				test_must_be_empty out &&
+				test_cmp expect actual
+			fi
+		'
+
+		test_expect_success "cat-file $arg1 $arg2 error on bogus full OID" '
+			if test "$arg2" = "-p"
+			then
+				cat >expect <<-EOF
+				error: header for $bogus_long_sha1 too long, exceeds 32 bytes
+				fatal: Not a valid object name $bogus_long_sha1
+				EOF
+			else
+				cat >expect <<-EOF
+				error: header for $bogus_long_sha1 too long, exceeds 32 bytes
+				fatal: git cat-file: could not get object info
+				EOF
+			fi &&
+
+			if test "$arg1" = "--allow-unknown-type"
+			then
+				git cat-file $arg1 $arg2 $bogus_short_sha1
+			else
+				test_must_fail git cat-file $arg1 $arg2 $bogus_long_sha1 >out 2>actual &&
+				test_must_be_empty out &&
+				test_cmp expect actual
+			fi
+		'
+
+		test_expect_success "cat-file $arg1 $arg2 error on missing short OID" '
+			cat >expect.err <<-EOF &&
+			fatal: Not a valid object name $(test_oid deadbeef_short)
+			EOF
+			test_must_fail git cat-file $arg1 $arg2 $(test_oid deadbeef_short) >out 2>err.actual &&
+			test_must_be_empty out
+		'
+
+		test_expect_success "cat-file $arg1 $arg2 error on missing full OID" '
+			if test "$arg2" = "-p"
+			then
+				cat >expect.err <<-EOF
+				fatal: Not a valid object name $(test_oid deadbeef)
+				EOF
+			else
+				cat >expect.err <<-\EOF
+				fatal: git cat-file: could not get object info
+				EOF
+			fi &&
+			test_must_fail git cat-file $arg1 $arg2 $(test_oid deadbeef) >out 2>err.actual &&
+			test_must_be_empty out &&
+			test_cmp expect.err err.actual
+		'
+	done
+done
+
+test_expect_success '-e is OK with a broken object without --allow-unknown-type' '
+	git cat-file -e $bogus_short_sha1
+'
+
+test_expect_success '-e can not be combined with --allow-unknown-type' '
+	test_expect_code 128 git cat-file -e --allow-unknown-type $bogus_short_sha1
+'
+
+test_expect_success '-p cannot print a broken object even with --allow-unknown-type' '
+	test_must_fail git cat-file -p $bogus_short_sha1 &&
+	test_expect_code 128 git cat-file -p --allow-unknown-type $bogus_short_sha1
+'
+
+test_expect_success '<type> <hash> does not work with objects of broken types' '
+	cat >err.expect <<-\EOF &&
+	fatal: invalid object type "bogus"
+	EOF
+	test_must_fail git cat-file $bogus_short_type $bogus_short_sha1 2>err.actual &&
+	test_cmp err.expect err.actual
+'
+
+test_expect_success 'broken types combined with --batch and --batch-check' '
+	echo $bogus_short_sha1 >bogus-oid &&
+
+	cat >err.expect <<-\EOF &&
+	fatal: invalid object type
+	EOF
+
+	test_must_fail git cat-file --batch <bogus-oid 2>err.actual &&
+	test_cmp err.expect err.actual &&
+
+	test_must_fail git cat-file --batch-check <bogus-oid 2>err.actual &&
+	test_cmp err.expect err.actual
+'
+
+test_expect_success 'the --batch and --batch-check options do not combine with --allow-unknown-type' '
+	test_expect_code 128 git cat-file --batch --allow-unknown-type <bogus-oid &&
+	test_expect_code 128 git cat-file --batch-check --allow-unknown-type <bogus-oid
+'
+
+test_expect_success 'the --allow-unknown-type option does not consider replacement refs' '
+	cat >expect <<-EOF &&
+	$bogus_short_type
+	EOF
+	git cat-file -t --allow-unknown-type $bogus_short_sha1 >actual &&
+	test_cmp expect actual &&
+
+	# Create it manually, as "git replace" will die on bogus
+	# types.
+	head=$(git rev-parse --verify HEAD) &&
+	test_when_finished "rm -rf .git/refs/replace" &&
+	mkdir -p .git/refs/replace &&
+	echo $head >.git/refs/replace/$bogus_short_sha1 &&
+
+	cat >expect <<-EOF &&
+	commit
+	EOF
+	git cat-file -t --allow-unknown-type $bogus_short_sha1 >actual &&
+	test_cmp expect actual
+'
 
 test_expect_success "Type of broken object is correct" '
-	echo $bogus_type >expect &&
-	git cat-file -t --allow-unknown-type $bogus_sha1 >actual &&
+	echo $bogus_short_type >expect &&
+	git cat-file -t --allow-unknown-type $bogus_short_sha1 >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success "Size of broken object is correct" '
-	echo $bogus_size >expect &&
-	git cat-file -s --allow-unknown-type $bogus_sha1 >actual &&
+	echo $bogus_short_size >expect &&
+	git cat-file -s --allow-unknown-type $bogus_short_sha1 >actual &&
 	test_cmp expect actual
 '
-bogus_type="abcdefghijklmnopqrstuvwxyz1234679"
-bogus_content="bogus"
-bogus_size=$(strlen "$bogus_content")
-bogus_sha1=$(echo_without_newline "$bogus_content" | git hash-object -t $bogus_type --literally -w --stdin)
+
+test_expect_success 'clean up broken object' '
+	rm .git/objects/$(test_oid_to_path $bogus_short_sha1)
+'
 
 test_expect_success "Type of broken object is correct when type is large" '
-	echo $bogus_type >expect &&
-	git cat-file -t --allow-unknown-type $bogus_sha1 >actual &&
+	echo $bogus_long_type >expect &&
+	git cat-file -t --allow-unknown-type $bogus_long_sha1 >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success "Size of large broken object is correct when type is large" '
-	echo $bogus_size >expect &&
-	git cat-file -s --allow-unknown-type $bogus_sha1 >actual &&
+	echo $bogus_long_size >expect &&
+	git cat-file -s --allow-unknown-type $bogus_long_sha1 >actual &&
 	test_cmp expect actual
 '
 
+test_expect_success 'clean up broken object' '
+	rm .git/objects/$(test_oid_to_path $bogus_long_sha1)
+'
+
+test_expect_success 'cat-file -t and -s on corrupt loose object' '
+	git init --bare corrupt-loose.git &&
+	(
+		cd corrupt-loose.git &&
+
+		# Setup and create the empty blob and its path
+		empty_path=$(git rev-parse --git-path objects/$(test_oid_to_path "$EMPTY_BLOB")) &&
+		git hash-object -w --stdin </dev/null &&
+
+		# Create another blob and its path
+		echo other >other.blob &&
+		other_blob=$(git hash-object -w --stdin <other.blob) &&
+		other_path=$(git rev-parse --git-path objects/$(test_oid_to_path "$other_blob")) &&
+
+		# Before the swap the size is 0
+		cat >out.expect <<-EOF &&
+		0
+		EOF
+		git cat-file -s "$EMPTY_BLOB" >out.actual 2>err.actual &&
+		test_must_be_empty err.actual &&
+		test_cmp out.expect out.actual &&
+
+		# Swap the two to corrupt the repository
+		mv -f "$other_path" "$empty_path" &&
+		test_must_fail git fsck 2>err.fsck &&
+		grep "hash-path mismatch" err.fsck &&
+
+		# confirm that cat-file is reading the new swapped-in
+		# blob...
+		cat >out.expect <<-EOF &&
+		blob
+		EOF
+		git cat-file -t "$EMPTY_BLOB" >out.actual 2>err.actual &&
+		test_must_be_empty err.actual &&
+		test_cmp out.expect out.actual &&
+
+		# ... since it has a different size now.
+		cat >out.expect <<-EOF &&
+		6
+		EOF
+		git cat-file -s "$EMPTY_BLOB" >out.actual 2>err.actual &&
+		test_must_be_empty err.actual &&
+		test_cmp out.expect out.actual &&
+
+		# So far "cat-file" has been happy to spew the found
+		# content out as-is. Try to make it zlib-invalid.
+		mv -f other.blob "$empty_path" &&
+		test_must_fail git fsck 2>err.fsck &&
+		grep "^error: inflate: data stream error (" err.fsck
+	)
+'
+
 # Tests for git cat-file --follow-symlinks
 test_expect_success 'prep for symlink tests' '
 	echo_without_newline "$hello_content" >morx &&
@@ -608,4 +807,70 @@
 	cmp expect actual
 '
 
+test_expect_success 'set up replacement object' '
+	orig=$(git rev-parse HEAD) &&
+	git cat-file commit $orig >orig &&
+	{
+		cat orig &&
+		echo extra
+	} >fake &&
+	fake=$(git hash-object -t commit -w fake) &&
+	orig_size=$(git cat-file -s $orig) &&
+	fake_size=$(git cat-file -s $fake) &&
+	git replace $orig $fake
+'
+
+test_expect_success 'cat-file --batch respects replace objects' '
+	git cat-file --batch >actual <<-EOF &&
+	$orig
+	EOF
+	{
+		echo "$orig commit $fake_size" &&
+		cat fake &&
+		echo
+	} >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'cat-file --batch-check respects replace objects' '
+	git cat-file --batch-check >actual <<-EOF &&
+	$orig
+	EOF
+	echo "$orig commit $fake_size" >expect &&
+	test_cmp expect actual
+'
+
+# Pull the entry for object with oid "$1" out of the output of
+# "cat-file --batch", including its object content (which requires
+# parsing and reading a set amount of bytes, hence perl).
+extract_batch_output () {
+    perl -ne '
+	BEGIN { $oid = shift }
+	if (/^$oid \S+ (\d+)$/) {
+	    print;
+	    read STDIN, my $buf, $1;
+	    print $buf;
+	    print "\n";
+	}
+    ' "$@"
+}
+
+test_expect_success 'cat-file --batch-all-objects --batch ignores replace' '
+	git cat-file --batch-all-objects --batch >actual.raw &&
+	extract_batch_output $orig <actual.raw >actual &&
+	{
+		echo "$orig commit $orig_size" &&
+		cat orig &&
+		echo
+	} >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'cat-file --batch-all-objects --batch-check ignores replace' '
+	git cat-file --batch-all-objects --batch-check >actual.raw &&
+	grep ^$orig actual.raw >actual &&
+	echo "$orig commit $orig_size" >expect &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t1009-read-tree-new-index.sh b/t/t1009-read-tree-new-index.sh
index 2935f68..fc179ac 100755
--- a/t/t1009-read-tree-new-index.sh
+++ b/t/t1009-read-tree-new-index.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/t1010-mktree.sh b/t/t1010-mktree.sh
index b946f87..48bfad0 100755
--- a/t/t1010-mktree.sh
+++ b/t/t1010-mktree.sh
@@ -2,6 +2,7 @@
 
 test_description='git mktree'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t1012-read-tree-df.sh b/t/t1012-read-tree-df.sh
index 57f0770..cde93d2 100755
--- a/t/t1012-read-tree-df.sh
+++ b/t/t1012-read-tree-df.sh
@@ -2,6 +2,7 @@
 
 test_description='read-tree D/F conflict corner cases'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-read-tree.sh
 
diff --git a/t/t1013-read-tree-submodule.sh b/t/t1013-read-tree-submodule.sh
index b6df744..bfc90d4 100755
--- a/t/t1013-read-tree-submodule.sh
+++ b/t/t1013-read-tree-submodule.sh
@@ -6,7 +6,6 @@
 . "$TEST_DIRECTORY"/lib-submodule-update.sh
 
 KNOWN_FAILURE_DIRECTORY_SUBMODULE_CONFLICTS=1
-KNOWN_FAILURE_SUBMODULE_OVERWRITE_IGNORED_UNTRACKED=1
 
 test_submodule_switch_recursing_with_args "read-tree -u -m"
 
diff --git a/t/t1014-read-tree-confusing.sh b/t/t1014-read-tree-confusing.sh
index da3376b..8ea8d36 100755
--- a/t/t1014-read-tree-confusing.sh
+++ b/t/t1014-read-tree-confusing.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='check that read-tree rejects confusing paths'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'create base tree' '
diff --git a/t/t1091-sparse-checkout-builtin.sh b/t/t1091-sparse-checkout-builtin.sh
index 38fc834..272ba1b 100755
--- a/t/t1091-sparse-checkout-builtin.sh
+++ b/t/t1091-sparse-checkout-builtin.sh
@@ -206,16 +206,21 @@
 '
 
 test_expect_success 'sparse-index enabled and disabled' '
-	git -C repo sparse-checkout init --cone --sparse-index &&
-	test_cmp_config -C repo true index.sparse &&
-	test-tool -C repo read-cache --table >cache &&
-	grep " tree " cache &&
+	(
+		sane_unset GIT_TEST_SPLIT_INDEX &&
+		git -C repo update-index --no-split-index &&
 
-	git -C repo sparse-checkout disable &&
-	test-tool -C repo read-cache --table >cache &&
-	! grep " tree " cache &&
-	git -C repo config --list >config &&
-	! grep index.sparse config
+		git -C repo sparse-checkout init --cone --sparse-index &&
+		test_cmp_config -C repo true index.sparse &&
+		test-tool -C repo read-cache --table >cache &&
+		grep " tree " cache &&
+
+		git -C repo sparse-checkout disable &&
+		test-tool -C repo read-cache --table >cache &&
+		! grep " tree " cache &&
+		git -C repo config --list >config &&
+		! grep index.sparse config
+	)
 '
 
 test_expect_success 'cone mode: init and set' '
@@ -406,7 +411,7 @@
 	git -C unmerged sparse-checkout disable
 '
 
-test_expect_success 'sparse-checkout reapply' '
+test_expect_failure 'sparse-checkout reapply' '
 	git clone repo tweak &&
 
 	echo dirty >tweak/deep/deeper2/a &&
@@ -438,6 +443,8 @@
 	test_i18ngrep "warning.*The following paths are unmerged" err &&
 	test_path_is_file tweak/folder1/a &&
 
+	# NEEDSWORK: We are asking to update a file outside of the
+	# sparse-checkout cone, but this is no longer allowed.
 	git -C tweak add folder1/a &&
 	git -C tweak sparse-checkout reapply 2>err &&
 	test_must_be_empty err &&
@@ -642,4 +649,63 @@
 	check_files repo/deep a deeper1
 '
 
+test_expect_success 'cone mode clears ignored subdirectories' '
+	rm repo/.git/info/sparse-checkout &&
+
+	git -C repo sparse-checkout init --cone &&
+	git -C repo sparse-checkout set deep/deeper1 &&
+
+	cat >repo/.gitignore <<-\EOF &&
+	obj/
+	*.o
+	EOF
+
+	git -C repo add .gitignore &&
+	git -C repo commit -m ".gitignore" &&
+
+	mkdir -p repo/obj repo/folder1/obj repo/deep/deeper2/obj &&
+	for file in folder1/obj/a obj/a folder1/file.o folder1.o \
+		    deep/deeper2/obj/a deep/deeper2/file.o file.o
+	do
+		echo ignored >repo/$file || return 1
+	done &&
+
+	git -C repo status --porcelain=v2 >out &&
+	test_must_be_empty out &&
+
+	git -C repo sparse-checkout reapply &&
+	test_path_is_missing repo/folder1 &&
+	test_path_is_missing repo/deep/deeper2 &&
+	test_path_is_dir repo/obj &&
+	test_path_is_file repo/file.o &&
+
+	git -C repo status --porcelain=v2 >out &&
+	test_must_be_empty out &&
+
+	git -C repo sparse-checkout set deep/deeper2 &&
+	test_path_is_missing repo/deep/deeper1 &&
+	test_path_is_dir repo/deep/deeper2 &&
+	test_path_is_dir repo/obj &&
+	test_path_is_file repo/file.o &&
+
+	>repo/deep/deeper2/ignored.o &&
+	>repo/deep/deeper2/untracked &&
+
+	# When an untracked file is in the way, all untracked files
+	# (even ignored files) are preserved.
+	git -C repo sparse-checkout set folder1 2>err &&
+	grep "contains untracked files" err &&
+	test_path_is_file repo/deep/deeper2/ignored.o &&
+	test_path_is_file repo/deep/deeper2/untracked &&
+
+	# The rest of the cone matches expectation
+	test_path_is_missing repo/deep/deeper1 &&
+	test_path_is_dir repo/obj &&
+	test_path_is_file repo/file.o &&
+
+	git -C repo status --porcelain=v2 >out &&
+	echo "? deep/deeper2/untracked" >expect &&
+	test_cmp expect out
+'
+
 test_done
diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh
index 91e30d6..16fbd2c 100755
--- a/t/t1092-sparse-checkout-compatibility.sh
+++ b/t/t1092-sparse-checkout-compatibility.sh
@@ -47,7 +47,7 @@
 		git checkout -b base &&
 		for dir in folder1 folder2 deep
 		do
-			git checkout -b update-$dir &&
+			git checkout -b update-$dir base &&
 			echo "updated $dir" >$dir/a &&
 			git commit -a -m "update $dir" || return 1
 		done &&
@@ -114,6 +114,16 @@
 		git add . &&
 		git commit -m "file to dir" &&
 
+		for side in left right
+		do
+			git checkout -b merge-$side base &&
+			echo $side >>deep/deeper2/a &&
+			echo $side >>folder1/a &&
+			echo $side >>folder2/a &&
+			git add . &&
+			git commit -m "$side" || return 1
+		done &&
+
 		git checkout -b deepest base &&
 		echo "updated deepest" >deep/deeper1/deepest/a &&
 		git commit -a -m "update deepest" &&
@@ -177,6 +187,16 @@
 	test_cmp sparse-checkout-err sparse-index-err
 }
 
+test_sparse_unstaged () {
+	file=$1 &&
+	for repo in sparse-checkout sparse-index
+	do
+		# Skip "unmerged" paths
+		git -C $repo diff --staged --diff-filter=u -- "$file" >diff &&
+		test_must_be_empty diff || return 1
+	done
+}
+
 test_expect_success 'sparse-index contents' '
 	init_repos &&
 
@@ -281,6 +301,20 @@
 	test_all_match git checkout -
 '
 
+test_expect_success 'add outside sparse cone' '
+	init_repos &&
+
+	run_on_sparse mkdir folder1 &&
+	run_on_sparse ../edit-contents folder1/a &&
+	run_on_sparse ../edit-contents folder1/newfile &&
+	test_sparse_match test_must_fail git add folder1/a &&
+	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_sparse_unstaged folder1/a &&
+	test_sparse_match test_must_fail git add folder1/newfile &&
+	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_sparse_unstaged folder1/newfile
+'
+
 test_expect_success 'commit including unstaged changes' '
 	init_repos &&
 
@@ -312,9 +346,6 @@
 test_expect_success 'status/add: outside sparse cone' '
 	init_repos &&
 
-	# adding a "missing" file outside the cone should fail
-	test_sparse_match test_must_fail git add folder1/a &&
-
 	# folder1 is at HEAD, but outside the sparse cone
 	run_on_sparse mkdir folder1 &&
 	cp initial-repo/folder1/a sparse-checkout/folder1/a &&
@@ -330,21 +361,29 @@
 
 	test_sparse_match git status --porcelain=v2 &&
 
-	# This "git add folder1/a" fails with a warning
-	# in the sparse repos, differing from the full
-	# repo. This is intentional.
+	# Adding the path outside of the sparse-checkout cone should fail.
 	test_sparse_match test_must_fail git add folder1/a &&
+	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_sparse_unstaged folder1/a &&
 	test_sparse_match test_must_fail git add --refresh folder1/a &&
-	test_all_match git status --porcelain=v2 &&
+	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_sparse_unstaged folder1/a &&
+	test_sparse_match test_must_fail git add folder1/new &&
+	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_sparse_unstaged folder1/new &&
+	test_sparse_match git add --sparse folder1/a &&
+	test_sparse_match git add --sparse folder1/new &&
 
-	test_all_match git add . &&
+	test_all_match git add --sparse . &&
 	test_all_match git status --porcelain=v2 &&
 	test_all_match git commit -m folder1/new &&
+	test_all_match git rev-parse HEAD^{tree} &&
 
 	run_on_all ../edit-contents folder1/newer &&
-	test_all_match git add folder1/ &&
+	test_all_match git add --sparse folder1/ &&
 	test_all_match git status --porcelain=v2 &&
-	test_all_match git commit -m folder1/newer
+	test_all_match git commit -m folder1/newer &&
+	test_all_match git rev-parse HEAD^{tree}
 '
 
 test_expect_success 'checkout and reset --hard' '
@@ -472,16 +511,97 @@
 	test_sparse_match git reset update-folder2
 '
 
-test_expect_success 'merge' '
+test_expect_success 'merge, cherry-pick, and rebase' '
 	init_repos &&
 
-	test_all_match git checkout -b merge update-deep &&
-	test_all_match git merge -m "folder1" update-folder1 &&
-	test_all_match git rev-parse HEAD^{tree} &&
-	test_all_match git merge -m "folder2" update-folder2 &&
+	for OPERATION in "merge -m merge" cherry-pick "rebase --apply" "rebase --merge"
+	do
+		test_all_match git checkout -B temp update-deep &&
+		test_all_match git $OPERATION update-folder1 &&
+		test_all_match git rev-parse HEAD^{tree} &&
+		test_all_match git $OPERATION update-folder2 &&
+		test_all_match git rev-parse HEAD^{tree} || return 1
+	done
+'
+
+test_expect_success 'merge with conflict outside cone' '
+	init_repos &&
+
+	test_all_match git checkout -b merge-tip merge-left &&
+	test_all_match git status --porcelain=v2 &&
+	test_all_match test_must_fail git merge -m merge merge-right &&
+	test_all_match git status --porcelain=v2 &&
+
+	# Resolve the conflict in different ways:
+	# 1. Revert to the base
+	test_all_match git checkout base -- deep/deeper2/a &&
+	test_all_match git status --porcelain=v2 &&
+
+	# 2. Add the file with conflict markers
+	test_sparse_match test_must_fail git add folder1/a &&
+	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_sparse_unstaged folder1/a &&
+	test_all_match git add --sparse folder1/a &&
+	test_all_match git status --porcelain=v2 &&
+
+	# 3. Rename the file to another sparse filename and
+	#    accept conflict markers as resolved content.
+	run_on_all mv folder2/a folder2/z &&
+	test_sparse_match test_must_fail git add folder2 &&
+	grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+	test_sparse_unstaged folder2/z &&
+	test_all_match git add --sparse folder2 &&
+	test_all_match git status --porcelain=v2 &&
+
+	test_all_match git merge --continue &&
+	test_all_match git status --porcelain=v2 &&
 	test_all_match git rev-parse HEAD^{tree}
 '
 
+test_expect_success 'cherry-pick/rebase with conflict outside cone' '
+	init_repos &&
+
+	for OPERATION in cherry-pick rebase
+	do
+		test_all_match git checkout -B tip &&
+		test_all_match git reset --hard merge-left &&
+		test_all_match git status --porcelain=v2 &&
+		test_all_match test_must_fail git $OPERATION merge-right &&
+		test_all_match git status --porcelain=v2 &&
+
+		# Resolve the conflict in different ways:
+		# 1. Revert to the base
+		test_all_match git checkout base -- deep/deeper2/a &&
+		test_all_match git status --porcelain=v2 &&
+
+		# 2. Add the file with conflict markers
+		# NEEDSWORK: Even though the merge conflict removed the
+		# SKIP_WORKTREE bit from the index entry for folder1/a, we should
+		# warn that this is a problematic add.
+		test_sparse_match test_must_fail git add folder1/a &&
+		grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+		test_sparse_unstaged folder1/a &&
+		test_all_match git add --sparse folder1/a &&
+		test_all_match git status --porcelain=v2 &&
+
+		# 3. Rename the file to another sparse filename and
+		#    accept conflict markers as resolved content.
+		# NEEDSWORK: This mode now fails, because folder2/z is
+		# outside of the sparse-checkout cone and does not match an
+		# existing index entry with the SKIP_WORKTREE bit cleared.
+		run_on_all mv folder2/a folder2/z &&
+		test_sparse_match test_must_fail git add folder2 &&
+		grep "Disable or modify the sparsity rules" sparse-checkout-err &&
+		test_sparse_unstaged folder2/z &&
+		test_all_match git add --sparse folder2 &&
+		test_all_match git status --porcelain=v2 &&
+
+		test_all_match git $OPERATION --continue &&
+		test_all_match git status --porcelain=v2 &&
+		test_all_match git rev-parse HEAD^{tree} || return 1
+	done
+'
+
 test_expect_success 'merge with outside renames' '
 	init_repos &&
 
@@ -549,6 +669,7 @@
 test_expect_success 'submodule handling' '
 	init_repos &&
 
+	test_sparse_match git sparse-checkout add modules &&
 	test_all_match mkdir modules &&
 	test_all_match touch modules/a &&
 	test_all_match git add modules &&
@@ -558,6 +679,7 @@
 	test_all_match git commit -m "add submodule" &&
 
 	# having a submodule prevents "modules" from collapse
+	test_sparse_match git sparse-checkout set deep/deeper1 &&
 	test-tool -C sparse-index read-cache --table >cache &&
 	grep "100644 blob .*	modules/a" cache &&
 	grep "160000 commit $(git -C initial-repo rev-parse HEAD)	modules/sub" cache
@@ -575,8 +697,17 @@
 ensure_not_expanded () {
 	rm -f trace2.txt &&
 	echo >>sparse-index/untracked.txt &&
-	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
-		git -C sparse-index "$@" &&
+
+	if test "$1" = "!"
+	then
+		shift &&
+		test_must_fail env \
+			GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
+			git -C sparse-index "$@" || return 1
+	else
+		GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
+			git -C sparse-index "$@" || return 1
+	fi &&
 	test_region ! index ensure_full_index trace2.txt
 }
 
@@ -598,7 +729,42 @@
 	git -C sparse-index reset --hard &&
 	ensure_not_expanded checkout rename-out-to-out -- deep/deeper1 &&
 	git -C sparse-index reset --hard &&
-	ensure_not_expanded restore -s rename-out-to-out -- deep/deeper1
+	ensure_not_expanded restore -s rename-out-to-out -- deep/deeper1 &&
+
+	echo >>sparse-index/README.md &&
+	ensure_not_expanded add -A &&
+	echo >>sparse-index/extra.txt &&
+	ensure_not_expanded add extra.txt &&
+	echo >>sparse-index/untracked.txt &&
+	ensure_not_expanded add . &&
+
+	ensure_not_expanded checkout -f update-deep &&
+	test_config -C sparse-index pull.twohead ort &&
+	(
+		sane_unset GIT_TEST_MERGE_ALGORITHM &&
+		for OPERATION in "merge -m merge" cherry-pick rebase
+		do
+			ensure_not_expanded merge -m merge update-folder1 &&
+			ensure_not_expanded merge -m merge update-folder2 || return 1
+		done
+	)
+'
+
+test_expect_success 'sparse-index is not expanded: merge conflict in cone' '
+	init_repos &&
+
+	for side in right left
+	do
+		git -C sparse-index checkout -b expand-$side base &&
+		echo $side >sparse-index/deep/a &&
+		git -C sparse-index commit -a -m "$side" || return 1
+	done &&
+
+	(
+		sane_unset GIT_TEST_MERGE_ALGORITHM &&
+		git -C sparse-index config pull.twohead ort &&
+		ensure_not_expanded ! merge -m merged expand-right
+	)
 '
 
 # NEEDSWORK: a sparse-checkout behaves differently from a full checkout
diff --git a/t/t1100-commit-tree-options.sh b/t/t1100-commit-tree-options.sh
index ae66ba5..0f37a43 100755
--- a/t/t1100-commit-tree-options.sh
+++ b/t/t1100-commit-tree-options.sh
@@ -12,6 +12,7 @@
 "flags first and then non flag arguments" command line.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 cat >expected <<EOF
diff --git a/t/t1305-config-include.sh b/t/t1305-config-include.sh
index ccbb116..5cde79e 100755
--- a/t/t1305-config-include.sh
+++ b/t/t1305-config-include.sh
@@ -1,6 +1,7 @@
 #!/bin/sh
 
 test_description='test config file include directives'
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # Force setup_explicit_git_dir() to run until the end. This is needed
diff --git a/t/t1405-main-ref-store.sh b/t/t1405-main-ref-store.sh
index a237d98..49718b7 100755
--- a/t/t1405-main-ref-store.sh
+++ b/t/t1405-main-ref-store.sh
@@ -9,12 +9,18 @@
 
 RUN="test-tool ref-store main"
 
-test_expect_success 'pack_refs(PACK_REFS_ALL | PACK_REFS_PRUNE)' '
-	test_commit one &&
+
+test_expect_success 'setup' '
+	test_commit one
+'
+
+test_expect_success REFFILES 'pack_refs(PACK_REFS_ALL | PACK_REFS_PRUNE)' '
 	N=`find .git/refs -type f | wc -l` &&
 	test "$N" != 0 &&
-	$RUN pack-refs 3 &&
-	N=`find .git/refs -type f | wc -l`
+	ALL_OR_PRUNE_FLAG=3 &&
+	$RUN pack-refs ${ALL_OR_PRUNE_FLAG} &&
+	N=`find .git/refs -type f` &&
+	test -z "$N"
 '
 
 test_expect_success 'create_symref(FOO, refs/heads/main)' '
@@ -98,12 +104,12 @@
 
 test_expect_success 'delete_reflog(HEAD)' '
 	$RUN delete-reflog HEAD &&
-	! test -f .git/logs/HEAD
+	test_must_fail git reflog exists HEAD
 '
 
 test_expect_success 'create-reflog(HEAD)' '
 	$RUN create-reflog HEAD 1 &&
-	test -f .git/logs/HEAD
+	git reflog exists HEAD
 '
 
 test_expect_success 'delete_ref(refs/heads/foo)' '
diff --git a/t/t1410-reflog.sh b/t/t1410-reflog.sh
index 27b9080..d42f067 100755
--- a/t/t1410-reflog.sh
+++ b/t/t1410-reflog.sh
@@ -374,7 +374,9 @@
 	test_line_count = 3 actual
 '
 
-test_expect_success 'reflog expire operates on symref not referrent' '
+# This test takes a lock on an individual ref; this is not supported in
+# reftable.
+test_expect_success REFFILES 'reflog expire operates on symref not referrent' '
 	git branch --create-reflog the_symref &&
 	git branch --create-reflog referrent &&
 	git update-ref referrent HEAD &&
diff --git a/t/t1430-bad-ref-name.sh b/t/t1430-bad-ref-name.sh
index b1839e0..4c77cf8 100755
--- a/t/t1430-bad-ref-name.sh
+++ b/t/t1430-bad-ref-name.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 '
@@ -170,7 +171,7 @@
 	! grep -e "badname" output &&
 	! grep -e "broken\.\.\.symref" output &&
 	test_i18ngrep "ignoring ref with broken name refs/heads/broken\.\.\.ref" error &&
-	test_i18ngrep "ignoring broken ref refs/heads/badname" error &&
+	test_i18ngrep ! "ignoring broken ref refs/heads/badname" error &&
 	test_i18ngrep "ignoring ref with broken name refs/heads/broken\.\.\.symref" error
 '
 
diff --git a/t/t1450-fsck.sh b/t/t1450-fsck.sh
index 5071ac6..6337236 100755
--- a/t/t1450-fsck.sh
+++ b/t/t1450-fsck.sh
@@ -48,24 +48,70 @@
 	rm "$(sha1_file "$1")"
 }
 
-test_expect_success 'object with bad sha1' '
-	sha=$(echo blob | git hash-object -w --stdin) &&
-	old=$(test_oid_to_path "$sha") &&
-	new=$(dirname $old)/$(test_oid ff_2) &&
-	sha="$(dirname $new)$(basename $new)" &&
-	mv .git/objects/$old .git/objects/$new &&
-	test_when_finished "remove_object $sha" &&
-	git update-index --add --cacheinfo 100644 $sha foo &&
-	test_when_finished "git read-tree -u --reset HEAD" &&
-	tree=$(git write-tree) &&
-	test_when_finished "remove_object $tree" &&
-	cmt=$(echo bogus | git commit-tree $tree) &&
-	test_when_finished "remove_object $cmt" &&
-	git update-ref refs/heads/bogus $cmt &&
-	test_when_finished "git update-ref -d refs/heads/bogus" &&
+test_expect_success 'object with hash mismatch' '
+	git init --bare hash-mismatch &&
+	(
+		cd hash-mismatch &&
 
-	test_must_fail git fsck 2>out &&
-	test_i18ngrep "$sha.*corrupt" out
+		oid=$(echo blob | git hash-object -w --stdin) &&
+		oldoid=$oid &&
+		old=$(test_oid_to_path "$oid") &&
+		new=$(dirname $old)/$(test_oid ff_2) &&
+		oid="$(dirname $new)$(basename $new)" &&
+
+		mv objects/$old objects/$new &&
+		git update-index --add --cacheinfo 100644 $oid foo &&
+		tree=$(git write-tree) &&
+		cmt=$(echo bogus | git commit-tree $tree) &&
+		git update-ref refs/heads/bogus $cmt &&
+
+		test_must_fail git fsck 2>out &&
+		grep "$oldoid: hash-path mismatch, found at: .*$new" out
+	)
+'
+
+test_expect_success 'object with hash and type mismatch' '
+	git init --bare hash-type-mismatch &&
+	(
+		cd hash-type-mismatch &&
+
+		oid=$(echo blob | git hash-object -w --stdin -t garbage --literally) &&
+		oldoid=$oid &&
+		old=$(test_oid_to_path "$oid") &&
+		new=$(dirname $old)/$(test_oid ff_2) &&
+		oid="$(dirname $new)$(basename $new)" &&
+
+		mv objects/$old objects/$new &&
+		git update-index --add --cacheinfo 100644 $oid foo &&
+		tree=$(git write-tree) &&
+		cmt=$(echo bogus | git commit-tree $tree) &&
+		git update-ref refs/heads/bogus $cmt &&
+
+
+		test_must_fail git fsck 2>out &&
+		grep "^error: $oldoid: hash-path mismatch, found at: .*$new" out &&
+		grep "^error: $oldoid: object is of unknown type '"'"'garbage'"'"'" out
+	)
+'
+
+test_expect_success POSIXPERM 'zlib corrupt loose object output ' '
+	git init --bare corrupt-loose-output &&
+	(
+		cd corrupt-loose-output &&
+		oid=$(git hash-object -w --stdin --literally </dev/null) &&
+		oidf=objects/$(test_oid_to_path "$oid") &&
+		chmod 755 $oidf &&
+		echo extra garbage >>$oidf &&
+
+		cat >expect.error <<-EOF &&
+		error: garbage at end of loose object '\''$oid'\''
+		error: unable to unpack contents of ./$oidf
+		error: $oid: object corrupt or missing: ./$oidf
+		EOF
+		test_must_fail git fsck 2>actual &&
+		grep ^error: actual >error &&
+		test_cmp expect.error error
+	)
 '
 
 test_expect_success 'branch pointing to non-commit' '
@@ -865,4 +911,21 @@
 	test_i18ngrep "bad index file" errors
 '
 
+test_expect_success 'fsck error and recovery on invalid object type' '
+	git init --bare garbage-type &&
+	(
+		cd garbage-type &&
+
+		garbage_blob=$(git hash-object --stdin -w -t garbage --literally </dev/null) &&
+
+		cat >err.expect <<-\EOF &&
+		fatal: invalid object type
+		EOF
+		test_must_fail git fsck >out 2>err &&
+		grep -e "^error" -e "^fatal" err >errors &&
+		test_line_count = 1 errors &&
+		grep "$garbage_blob: object is of unknown type '"'"'garbage'"'"':" err
+	)
+'
+
 test_done
diff --git a/t/t1502-rev-parse-parseopt.sh b/t/t1502-rev-parse-parseopt.sh
index b29563f..284fe18 100755
--- a/t/t1502-rev-parse-parseopt.sh
+++ b/t/t1502-rev-parse-parseopt.sh
@@ -282,4 +282,58 @@
 	test_cmp expect output
 '
 
+test_expect_success 'test --parseopt help output: "wrapped" options normal "or:" lines' '
+	sed -e "s/^|//" >spec <<-\EOF &&
+	|cmd [--some-option]
+	|    [--another-option]
+	|cmd [--yet-another-option]
+	|--
+	|h,help    show the help
+	EOF
+
+	sed -e "s/^|//" >expect <<-\END_EXPECT &&
+	|cat <<\EOF
+	|usage: cmd [--some-option]
+	|   or:     [--another-option]
+	|   or: cmd [--yet-another-option]
+	|
+	|    -h, --help            show the help
+	|
+	|EOF
+	END_EXPECT
+
+	test_must_fail git rev-parse --parseopt -- -h >out <spec >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'test --parseopt help output: multi-line blurb after empty line' '
+	sed -e "s/^|//" >spec <<-\EOF &&
+	|cmd [--some-option]
+	|    [--another-option]
+	|
+	|multi
+	|line
+	|blurb
+	|--
+	|h,help    show the help
+	EOF
+
+	sed -e "s/^|//" >expect <<-\END_EXPECT &&
+	|cat <<\EOF
+	|usage: cmd [--some-option]
+	|   or:     [--another-option]
+	|
+	|    multi
+	|    line
+	|    blurb
+	|
+	|    -h, --help            show the help
+	|
+	|EOF
+	END_EXPECT
+
+	test_must_fail git rev-parse --parseopt -- -h >out <spec >actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t1503-rev-parse-verify.sh b/t/t1503-rev-parse-verify.sh
index bf08102..4095861 100755
--- a/t/t1503-rev-parse-verify.sh
+++ b/t/t1503-rev-parse-verify.sh
@@ -142,7 +142,7 @@
 	test_must_fail git rev-parse --verify main@{$Np1}
 '
 
-test_expect_success SYMLINKS 'ref resolution not confused by broken symlinks' '
+test_expect_success SYMLINKS,REFFILES 'ref resolution not confused by broken symlinks' '
 	ln -s does-not-exist .git/refs/heads/broken &&
 	test_must_fail git rev-parse --verify broken
 '
diff --git a/t/t1504-ceiling-dirs.sh b/t/t1504-ceiling-dirs.sh
index 3d51615..0fafcf9 100755
--- a/t/t1504-ceiling-dirs.sh
+++ b/t/t1504-ceiling-dirs.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='test GIT_CEILING_DIRECTORIES'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_prefix() {
diff --git a/t/t1510-repo-setup.sh b/t/t1510-repo-setup.sh
index bbfe05b..591505a 100755
--- a/t/t1510-repo-setup.sh
+++ b/t/t1510-repo-setup.sh
@@ -43,6 +43,7 @@
 # This test heavily relies on the standard error of nested function calls.
 test_untraceable=UnfortunatelyYes
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 here=$(pwd)
diff --git a/t/t1600-index.sh b/t/t1600-index.sh
index c9b9e71..46329c4 100755
--- a/t/t1600-index.sh
+++ b/t/t1600-index.sh
@@ -4,6 +4,8 @@
 
 . ./test-lib.sh
 
+sane_unset GIT_TEST_SPLIT_INDEX
+
 test_expect_success 'setup' '
 	echo 1 >a
 '
@@ -13,7 +15,8 @@
 		rm -f .git/index &&
 		GIT_INDEX_VERSION=2bogus &&
 		export GIT_INDEX_VERSION &&
-		git add a 2>&1 | sed "s/[0-9]//" >actual.err &&
+		git add a 2>err &&
+		sed "s/[0-9]//" err >actual.err &&
 		sed -e "s/ Z$/ /" <<-\EOF >expect.err &&
 			warning: GIT_INDEX_VERSION set, but the value is invalid.
 			Using version Z
@@ -27,7 +30,8 @@
 		rm -f .git/index &&
 		GIT_INDEX_VERSION=1 &&
 		export GIT_INDEX_VERSION &&
-		git add a 2>&1 | sed "s/[0-9]//" >actual.err &&
+		git add a 2>err &&
+		sed "s/[0-9]//" err >actual.err &&
 		sed -e "s/ Z$/ /" <<-\EOF >expect.err &&
 			warning: GIT_INDEX_VERSION set, but the value is invalid.
 			Using version Z
@@ -50,7 +54,8 @@
 		sane_unset GIT_INDEX_VERSION &&
 		rm -f .git/index &&
 		git config --add index.version 1 &&
-		git add a 2>&1 | sed "s/[0-9]//" >actual.err &&
+		git add a 2>err &&
+		sed "s/[0-9]//" err >actual.err &&
 		sed -e "s/ Z$/ /" <<-\EOF >expect.err &&
 			warning: index.version set, but the value is invalid.
 			Using version Z
@@ -79,7 +84,7 @@
 		else
 			unset GIT_INDEX_VERSION
 		fi &&
-		git add a 2>&1 &&
+		git add a &&
 		echo $EXPECTED_OUTPUT_VERSION >expect &&
 		test-tool index-version <.git/index >actual &&
 		test_cmp expect actual
diff --git a/t/t1700-split-index.sh b/t/t1700-split-index.sh
index 986baa6..decd252 100755
--- a/t/t1700-split-index.sh
+++ b/t/t1700-split-index.sh
@@ -510,4 +510,38 @@
 	)
 '
 
+test_expect_success 'reading split index at alternate location' '
+	git init reading-alternate-location &&
+	(
+		cd reading-alternate-location &&
+		>file-in-alternate &&
+		git update-index --split-index --add file-in-alternate
+	) &&
+	echo file-in-alternate >expect &&
+
+	# Should be able to find the shared index both right next to
+	# the specified split index file ...
+	GIT_INDEX_FILE=./reading-alternate-location/.git/index \
+	git ls-files --cached >actual &&
+	test_cmp expect actual &&
+
+	# ... and, for backwards compatibility, in the current GIT_DIR
+	# as well.
+	mv -v ./reading-alternate-location/.git/sharedindex.* .git &&
+	GIT_INDEX_FILE=./reading-alternate-location/.git/index \
+	git ls-files --cached >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'GIT_TEST_SPLIT_INDEX works' '
+	git init git-test-split-index &&
+	(
+		cd git-test-split-index &&
+		>file &&
+		GIT_TEST_SPLIT_INDEX=1 git update-index --add file &&
+		ls -l .git/sharedindex.* >actual &&
+		test_line_count = 1 actual
+	)
+'
+
 test_done
diff --git a/t/t2002-checkout-cache-u.sh b/t/t2002-checkout-cache-u.sh
index 70361c8..fc95cf9 100755
--- a/t/t2002-checkout-cache-u.sh
+++ b/t/t2002-checkout-cache-u.sh
@@ -8,6 +8,7 @@
 With -u flag, git checkout-index internally runs the equivalent of
 git update-index --refresh on the checked out entry.'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success \
diff --git a/t/t2003-checkout-cache-mkdir.sh b/t/t2003-checkout-cache-mkdir.sh
index ff163cf..f0fd441 100755
--- a/t/t2003-checkout-cache-mkdir.sh
+++ b/t/t2003-checkout-cache-mkdir.sh
@@ -10,6 +10,7 @@
 the GIT controlled paths.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t2004-checkout-cache-temp.sh b/t/t2004-checkout-cache-temp.sh
index a9352b0..9bb503a 100755
--- a/t/t2004-checkout-cache-temp.sh
+++ b/t/t2004-checkout-cache-temp.sh
@@ -8,6 +8,7 @@
 With --temp flag, git checkout-index writes to temporary merge files
 rather than the tracked path.'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t2005-checkout-index-symlinks.sh b/t/t2005-checkout-index-symlinks.sh
index 9fa5610..112682a 100755
--- a/t/t2005-checkout-index-symlinks.sh
+++ b/t/t2005-checkout-index-symlinks.sh
@@ -8,6 +8,7 @@
 This tests that git checkout-index creates a symbolic link as a plain
 file if core.symlinks is false.'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success \
diff --git a/t/t2021-checkout-overwrite.sh b/t/t2021-checkout-overwrite.sh
index 70d6926..660132f 100755
--- a/t/t2021-checkout-overwrite.sh
+++ b/t/t2021-checkout-overwrite.sh
@@ -48,6 +48,7 @@
 
 test_expect_success SYMLINKS 'the symlink remained' '
 
+	test_when_finished "rm a/b" &&
 	test -h a/b
 '
 
diff --git a/t/t2050-git-dir-relative.sh b/t/t2050-git-dir-relative.sh
index 21f4659..1f193cd 100755
--- a/t/t2050-git-dir-relative.sh
+++ b/t/t2050-git-dir-relative.sh
@@ -12,6 +12,7 @@
 and tries commits from the top and the subdir, checking
 that the commit-hook still gets called.'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 COMMIT_FILE="$(pwd)/output"
diff --git a/t/t2081-parallel-checkout-collisions.sh b/t/t2081-parallel-checkout-collisions.sh
index f6fcfc0..6acdb89 100755
--- a/t/t2081-parallel-checkout-collisions.sh
+++ b/t/t2081-parallel-checkout-collisions.sh
@@ -11,6 +11,7 @@
 both these mechanics.
 "
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY/lib-parallel-checkout.sh"
 
diff --git a/t/t2200-add-update.sh b/t/t2200-add-update.sh
index 45ca35d..94c4cb0 100755
--- a/t/t2200-add-update.sh
+++ b/t/t2200-add-update.sh
@@ -129,12 +129,15 @@
 		echo "remove '\''top'\''"
 	) >expect &&
 	before=$(git ls-files -s check top) &&
+	git count-objects -v >objects_before &&
 	echo changed >>check &&
 	rm -f top &&
 	git add -n -u >actual &&
 	after=$(git ls-files -s check top) &&
+	git count-objects -v >objects_after &&
 
 	test "$before" = "$after" &&
+	test_cmp objects_before objects_after &&
 	test_cmp expect actual
 
 '
diff --git a/t/t2300-cd-to-toplevel.sh b/t/t2300-cd-to-toplevel.sh
index c8de6d8..b40eeb2 100755
--- a/t/t2300-cd-to-toplevel.sh
+++ b/t/t2300-cd-to-toplevel.sh
@@ -2,6 +2,7 @@
 
 test_description='cd_to_toplevel'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 EXEC_PATH="$(git --exec-path)"
diff --git a/t/t2402-worktree-list.sh b/t/t2402-worktree-list.sh
index fedcefe..4012bd6 100755
--- a/t/t2402-worktree-list.sh
+++ b/t/t2402-worktree-list.sh
@@ -230,7 +230,7 @@
 		EOF
 		cd linked &&
 		echo "worktree $(pwd)" >expected &&
-		echo "ref: .broken" >../.git/HEAD &&
+		(cd ../ && test-tool ref-store main create-symref HEAD .broken ) &&
 		git worktree list --porcelain >out &&
 		head -n 3 out >actual &&
 		test_cmp ../expected actual &&
diff --git a/t/t2500-untracked-overwriting.sh b/t/t2500-untracked-overwriting.sh
new file mode 100755
index 0000000..5c0bf4d
--- /dev/null
+++ b/t/t2500-untracked-overwriting.sh
@@ -0,0 +1,244 @@
+#!/bin/sh
+
+test_description='Test handling of overwriting untracked files'
+
+. ./test-lib.sh
+
+test_setup_reset () {
+	git init reset_$1 &&
+	(
+		cd reset_$1 &&
+		test_commit init &&
+
+		git branch stable &&
+		git branch work &&
+
+		git checkout work &&
+		test_commit foo &&
+
+		git checkout stable
+	)
+}
+
+test_expect_success 'reset --hard will nuke untracked files/dirs' '
+	test_setup_reset hard &&
+	(
+		cd reset_hard &&
+		git ls-tree -r stable &&
+		git log --all --name-status --oneline &&
+		git ls-tree -r work &&
+
+		mkdir foo.t &&
+		echo precious >foo.t/file &&
+		echo foo >expect &&
+
+		git reset --hard work &&
+
+		# check that untracked directory foo.t/ was nuked
+		test_path_is_file foo.t &&
+		test_cmp expect foo.t
+	)
+'
+
+test_expect_success 'reset --merge will preserve untracked files/dirs' '
+	test_setup_reset merge &&
+	(
+		cd reset_merge &&
+
+		mkdir foo.t &&
+		echo precious >foo.t/file &&
+		cp foo.t/file expect &&
+
+		test_must_fail git reset --merge work 2>error &&
+		test_cmp expect foo.t/file &&
+		grep "Updating .foo.t. would lose untracked files" error
+	)
+'
+
+test_expect_success 'reset --keep will preserve untracked files/dirs' '
+	test_setup_reset keep &&
+	(
+		cd reset_keep &&
+
+		mkdir foo.t &&
+		echo precious >foo.t/file &&
+		cp foo.t/file expect &&
+
+		test_must_fail git reset --merge work 2>error &&
+		test_cmp expect foo.t/file &&
+		grep "Updating.*foo.t.*would lose untracked files" error
+	)
+'
+
+test_setup_checkout_m () {
+	git init checkout &&
+	(
+		cd checkout &&
+		test_commit init &&
+
+		test_write_lines file has some >filler &&
+		git add filler &&
+		git commit -m filler &&
+
+		git branch stable &&
+
+		git switch -c work &&
+		echo stuff >notes.txt &&
+		test_write_lines file has some words >filler &&
+		git add notes.txt filler &&
+		git commit -m filler &&
+
+		git checkout stable
+	)
+}
+
+test_expect_success 'checkout -m does not nuke untracked file' '
+	test_setup_checkout_m &&
+	(
+		cd checkout &&
+
+		# Tweak filler
+		test_write_lines this file has some >filler &&
+		# Make an untracked file, save its contents in "expect"
+		echo precious >notes.txt &&
+		cp notes.txt expect &&
+
+		test_must_fail git checkout -m work &&
+		test_cmp expect notes.txt
+	)
+'
+
+test_setup_sequencing () {
+	git init sequencing_$1 &&
+	(
+		cd sequencing_$1 &&
+		test_commit init &&
+
+		test_write_lines this file has some words >filler &&
+		git add filler &&
+		git commit -m filler &&
+
+		mkdir -p foo/bar &&
+		test_commit foo/bar/baz &&
+
+		git branch simple &&
+		git branch fooey &&
+
+		git checkout fooey &&
+		git rm foo/bar/baz.t &&
+		echo stuff >>filler &&
+		git add -u &&
+		git commit -m "changes" &&
+
+		git checkout simple &&
+		echo items >>filler &&
+		echo newstuff >>newfile &&
+		git add filler newfile &&
+		git commit -m another
+	)
+}
+
+test_expect_success 'git rebase --abort and untracked files' '
+	test_setup_sequencing rebase_abort_and_untracked &&
+	(
+		cd sequencing_rebase_abort_and_untracked &&
+		git checkout fooey &&
+		test_must_fail git rebase simple &&
+
+		cat init.t &&
+		git rm init.t &&
+		echo precious >init.t &&
+		cp init.t expect &&
+		git status --porcelain &&
+		test_must_fail git rebase --abort &&
+		test_cmp expect init.t
+	)
+'
+
+test_expect_success 'git rebase fast forwarding and untracked files' '
+	test_setup_sequencing rebase_fast_forward_and_untracked &&
+	(
+		cd sequencing_rebase_fast_forward_and_untracked &&
+		git checkout init &&
+		echo precious >filler &&
+		cp filler expect &&
+		test_must_fail git rebase init simple &&
+		test_cmp expect filler
+	)
+'
+
+test_expect_failure 'git rebase --autostash and untracked files' '
+	test_setup_sequencing rebase_autostash_and_untracked &&
+	(
+		cd sequencing_rebase_autostash_and_untracked &&
+		git checkout simple &&
+		git rm filler &&
+		mkdir filler &&
+		echo precious >filler/file &&
+		cp filler/file expect &&
+		git rebase --autostash init &&
+		test_path_is_file filler/file
+	)
+'
+
+test_expect_failure 'git stash and untracked files' '
+	test_setup_sequencing stash_and_untracked_files &&
+	(
+		cd sequencing_stash_and_untracked_files &&
+		git checkout simple &&
+		git rm filler &&
+		mkdir filler &&
+		echo precious >filler/file &&
+		cp filler/file expect &&
+		git status --porcelain &&
+		git stash push &&
+		git status --porcelain &&
+		test_path_is_file filler/file
+	)
+'
+
+test_expect_success 'git am --abort and untracked dir vs. unmerged file' '
+	test_setup_sequencing am_abort_and_untracked &&
+	(
+		cd sequencing_am_abort_and_untracked &&
+		git format-patch -1 --stdout fooey >changes.mbox &&
+		test_must_fail git am --3way changes.mbox &&
+
+		# Delete the conflicted file; we will stage and commit it later
+		rm filler &&
+
+		# Put an unrelated untracked directory there
+		mkdir filler &&
+		echo foo >filler/file1 &&
+		echo bar >filler/file2 &&
+
+		test_must_fail git am --abort 2>errors &&
+		test_path_is_dir filler &&
+		grep "Updating .filler. would lose untracked files in it" errors
+	)
+'
+
+test_expect_success 'git am --skip and untracked dir vs deleted file' '
+	test_setup_sequencing am_skip_and_untracked &&
+	(
+		cd sequencing_am_skip_and_untracked &&
+		git checkout fooey &&
+		git format-patch -1 --stdout simple >changes.mbox &&
+		test_must_fail git am --3way changes.mbox &&
+
+		# Delete newfile
+		rm newfile &&
+
+		# Put an unrelated untracked directory there
+		mkdir newfile &&
+		echo foo >newfile/file1 &&
+		echo bar >newfile/file2 &&
+
+		# Change our mind about resolutions, just skip this patch
+		test_must_fail git am --skip 2>errors &&
+		test_path_is_dir newfile &&
+		grep "Updating .newfile. would lose untracked files in it" errors
+	)
+'
+
+test_done
diff --git a/t/t3000-ls-files-others.sh b/t/t3000-ls-files-others.sh
index 740ce56..11af455 100755
--- a/t/t3000-ls-files-others.sh
+++ b/t/t3000-ls-files-others.sh
@@ -15,6 +15,8 @@
     path3/file3 - a file in a directory
     path4       - an empty directory
 '
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup ' '
diff --git a/t/t3001-ls-files-others-exclude.sh b/t/t3001-ls-files-others-exclude.sh
index 516c95e..48cec4e 100755
--- a/t/t3001-ls-files-others-exclude.sh
+++ b/t/t3001-ls-files-others-exclude.sh
@@ -8,6 +8,7 @@
 This test runs git ls-files --others and tests --exclude patterns.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 rm -fr one three
@@ -102,7 +103,7 @@
        >output &&
      test_cmp expect output'
 
-test_expect_success 'restore gitignore' '
+test_expect_success !SANITIZE_LEAK 'restore gitignore' '
 	git checkout --ignore-skip-worktree-bits $allignores &&
 	rm .git/index
 '
@@ -125,7 +126,7 @@
 #	three/
 EOF
 
-test_expect_success 'git status honors core.excludesfile' \
+test_expect_success !SANITIZE_LEAK 'git status honors core.excludesfile' \
 	'test_cmp expect output'
 
 test_expect_success 'trailing slash in exclude allows directory match(1)' '
diff --git a/t/t3002-ls-files-dashpath.sh b/t/t3002-ls-files-dashpath.sh
index 8704b04..54d22a4 100755
--- a/t/t3002-ls-files-dashpath.sh
+++ b/t/t3002-ls-files-dashpath.sh
@@ -12,6 +12,8 @@
     -foo	- a file with a funny name.
     --		- another file with a funny name.
 '
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success \
diff --git a/t/t3003-ls-files-exclude.sh b/t/t3003-ls-files-exclude.sh
index c41c4f0..7933dff 100755
--- a/t/t3003-ls-files-exclude.sh
+++ b/t/t3003-ls-files-exclude.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='ls-files --exclude does not affect index files'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'create repo with file' '
diff --git a/t/t3004-ls-files-basic.sh b/t/t3004-ls-files-basic.sh
index 9fd5a1f..a16e25c 100755
--- a/t/t3004-ls-files-basic.sh
+++ b/t/t3004-ls-files-basic.sh
@@ -6,6 +6,7 @@
 command-line arguments.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'ls-files in empty repository' '
diff --git a/t/t3005-ls-files-relative.sh b/t/t3005-ls-files-relative.sh
index 727e9ae..6ba8b58 100755
--- a/t/t3005-ls-files-relative.sh
+++ b/t/t3005-ls-files-relative.sh
@@ -5,6 +5,7 @@
 This test runs git ls-files with various relative path arguments.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'prepare' '
diff --git a/t/t3006-ls-files-long.sh b/t/t3006-ls-files-long.sh
index e109c3f..2aaf91e 100755
--- a/t/t3006-ls-files-long.sh
+++ b/t/t3006-ls-files-long.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='overly long paths'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t3008-ls-files-lazy-init-name-hash.sh b/t/t3008-ls-files-lazy-init-name-hash.sh
index 85f3704..51d3dff 100755
--- a/t/t3008-ls-files-lazy-init-name-hash.sh
+++ b/t/t3008-ls-files-lazy-init-name-hash.sh
@@ -2,6 +2,7 @@
 
 test_description='Test the lazy init name hash with various folder structures'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 if test 1 -eq $(test-tool online-cpus)
diff --git a/t/t3020-ls-files-error-unmatch.sh b/t/t3020-ls-files-error-unmatch.sh
index 124e73b..2cbcbc0 100755
--- a/t/t3020-ls-files-error-unmatch.sh
+++ b/t/t3020-ls-files-error-unmatch.sh
@@ -9,6 +9,8 @@
 returns an error when a non-existent path is provided on the command
 line.
 '
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t3070-wildmatch.sh b/t/t3070-wildmatch.sh
index 56ea4bd..72d5b01 100755
--- a/t/t3070-wildmatch.sh
+++ b/t/t3070-wildmatch.sh
@@ -2,6 +2,7 @@
 
 test_description='wildmatch tests'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # Disable expensive chain-lint tests; all of the tests in this script
diff --git a/t/t3100-ls-tree-restrict.sh b/t/t3100-ls-tree-restrict.sh
index 18baf49..436de44 100755
--- a/t/t3100-ls-tree-restrict.sh
+++ b/t/t3100-ls-tree-restrict.sh
@@ -16,6 +16,8 @@
 The new path restriction code should do the right thing for path2 and
 path2/baz.  Also path0/ should snow nothing.
 '
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success \
diff --git a/t/t3101-ls-tree-dirname.sh b/t/t3101-ls-tree-dirname.sh
index 12bf310..05fde64 100755
--- a/t/t3101-ls-tree-dirname.sh
+++ b/t/t3101-ls-tree-dirname.sh
@@ -19,6 +19,8 @@
 Test the handling of multiple directories which have matching file
 entries.  Also test odd filename and missing entries handling.
 '
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t3102-ls-tree-wildcards.sh b/t/t3102-ls-tree-wildcards.sh
index 1e16c6b..3942db2 100755
--- a/t/t3102-ls-tree-wildcards.sh
+++ b/t/t3102-ls-tree-wildcards.sh
@@ -2,6 +2,7 @@
 
 test_description='ls-tree with(out) globs'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t3103-ls-tree-misc.sh b/t/t3103-ls-tree-misc.sh
index 1452091..d18ba1b 100755
--- a/t/t3103-ls-tree-misc.sh
+++ b/t/t3103-ls-tree-misc.sh
@@ -7,6 +7,7 @@
 
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success 'setup' '
diff --git a/t/t3203-branch-output.sh b/t/t3203-branch-output.sh
index 5325b9f..6e94c6d 100755
--- a/t/t3203-branch-output.sh
+++ b/t/t3203-branch-output.sh
@@ -340,6 +340,10 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'git branch with --format=%(rest) must fail' '
+	test_must_fail git branch --format="%(rest)" >actual
+'
+
 test_expect_success 'worktree colors correct' '
 	cat >expect <<-EOF &&
 	* <GREEN>(HEAD detached from fromtag)<RESET>
diff --git a/t/t3205-branch-color.sh b/t/t3205-branch-color.sh
index 08bd906..6a521c1 100755
--- a/t/t3205-branch-color.sh
+++ b/t/t3205-branch-color.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 some sample branches' '
diff --git a/t/t3211-peel-ref.sh b/t/t3211-peel-ref.sh
index 37b9d26..9cbc34f 100755
--- a/t/t3211-peel-ref.sh
+++ b/t/t3211-peel-ref.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 'create annotated tag in refs/tags' '
diff --git a/t/t3300-funny-names.sh b/t/t3300-funny-names.sh
index f5bf16a..d3ac826 100755
--- a/t/t3300-funny-names.sh
+++ b/t/t3300-funny-names.sh
@@ -9,6 +9,7 @@
 tree, index, and tree objects.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 HT='	'
diff --git a/t/t3320-notes-merge-worktrees.sh b/t/t3320-notes-merge-worktrees.sh
index 052516e..6b2d507 100755
--- a/t/t3320-notes-merge-worktrees.sh
+++ b/t/t3320-notes-merge-worktrees.sh
@@ -46,8 +46,9 @@
 test_expect_success 'merge z into y fails and sets NOTES_MERGE_REF' '
 	git config core.notesRef refs/notes/y &&
 	test_must_fail git notes merge z &&
-	echo "ref: refs/notes/y" >expect &&
-	test_cmp expect .git/NOTES_MERGE_REF
+	echo "refs/notes/y" >expect &&
+	git symbolic-ref NOTES_MERGE_REF >actual &&
+	test_cmp expect actual
 '
 
 test_expect_success 'merge z into y while mid-merge in another workdir fails' '
@@ -57,7 +58,7 @@
 		test_must_fail git notes merge z 2>err &&
 		test_i18ngrep "a notes merge into refs/notes/y is already in-progress at" err
 	) &&
-	test_path_is_missing .git/worktrees/worktree/NOTES_MERGE_REF
+	test_must_fail git -C worktree symbolic-ref NOTES_MERGE_REF
 '
 
 test_expect_success 'merge z into x while mid-merge on y succeeds' '
@@ -68,8 +69,9 @@
 		test_i18ngrep "Automatic notes merge failed" out &&
 		grep -v "A notes merge into refs/notes/x is already in-progress in" out
 	) &&
-	echo "ref: refs/notes/x" >expect &&
-	test_cmp expect .git/worktrees/worktree2/NOTES_MERGE_REF
+	echo "refs/notes/x" >expect &&
+	git -C worktree2 symbolic-ref NOTES_MERGE_REF >actual &&
+	test_cmp expect actual
 '
 
 test_done
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index d877872..12eb226 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -297,6 +297,7 @@
 		output &&
 	test_i18ngrep "file1" output &&
 	test_path_is_missing .git/rebase-merge &&
+	rm file1 &&
 	git reset --hard HEAD^
 '
 
@@ -351,82 +352,6 @@
 	git show HEAD | grep "^Author: Twerp Snog"
 '
 
-test_expect_success REBASE_P '-p handles "no changes" gracefully' '
-	HEAD=$(git rev-parse HEAD) &&
-	git rebase -i -p HEAD^ &&
-	git update-index --refresh &&
-	git diff-files --quiet &&
-	git diff-index --quiet --cached HEAD -- &&
-	test $HEAD = $(git rev-parse HEAD)
-'
-
-test_expect_failure REBASE_P 'exchange two commits with -p' '
-	git checkout H &&
-	(
-		set_fake_editor &&
-		FAKE_LINES="2 1" git rebase -i -p HEAD~2
-	) &&
-	test H = $(git cat-file commit HEAD^ | sed -ne \$p) &&
-	test G = $(git cat-file commit HEAD | sed -ne \$p)
-'
-
-test_expect_success REBASE_P 'preserve merges with -p' '
-	git checkout -b to-be-preserved primary^ &&
-	: > unrelated-file &&
-	git add unrelated-file &&
-	test_tick &&
-	git commit -m "unrelated" &&
-	git checkout -b another-branch primary &&
-	echo B > file1 &&
-	test_tick &&
-	git commit -m J file1 &&
-	test_tick &&
-	git merge to-be-preserved &&
-	echo C > file1 &&
-	test_tick &&
-	git commit -m K file1 &&
-	echo D > file1 &&
-	test_tick &&
-	git commit -m L1 file1 &&
-	git checkout HEAD^ &&
-	echo 1 > unrelated-file &&
-	test_tick &&
-	git commit -m L2 unrelated-file &&
-	test_tick &&
-	git merge another-branch &&
-	echo E > file1 &&
-	test_tick &&
-	git commit -m M file1 &&
-	git checkout -b to-be-rebased &&
-	test_tick &&
-	git rebase -i -p --onto branch1 primary &&
-	git update-index --refresh &&
-	git diff-files --quiet &&
-	git diff-index --quiet --cached HEAD -- &&
-	test_cmp_rev HEAD~6 branch1 &&
-	test_cmp_rev HEAD~4^2 to-be-preserved &&
-	test_cmp_rev HEAD^^2^ HEAD^^^ &&
-	test $(git show HEAD~5:file1) = B &&
-	test $(git show HEAD~3:file1) = C &&
-	test $(git show HEAD:file1) = E &&
-	test $(git show HEAD:unrelated-file) = 1
-'
-
-test_expect_success REBASE_P 'edit ancestor with -p' '
-	(
-		set_fake_editor &&
-		FAKE_LINES="1 2 edit 3 4" git rebase -i -p HEAD~3
-	) &&
-	echo 2 > unrelated-file &&
-	test_tick &&
-	git commit -m L2-modified --amend unrelated-file &&
-	git rebase --continue &&
-	git update-index --refresh &&
-	git diff-files --quiet &&
-	git diff-index --quiet --cached HEAD -- &&
-	test $(git show HEAD:unrelated-file) = 2
-'
-
 test_expect_success '--continue tries to commit' '
 	git reset --hard D &&
 	test_tick &&
diff --git a/t/t3407-rebase-abort.sh b/t/t3407-rebase-abort.sh
index 7c381fb..ebbaed1 100755
--- a/t/t3407-rebase-abort.sh
+++ b/t/t3407-rebase-abort.sh
@@ -7,77 +7,77 @@
 
 . ./test-lib.sh
 
-### Test that we handle space characters properly
-work_dir="$(pwd)/test dir"
-
 test_expect_success setup '
-	mkdir -p "$work_dir" &&
-	cd "$work_dir" &&
-	git init &&
-	echo a > a &&
-	git add a &&
-	git commit -m a &&
+	test_commit a a a &&
 	git branch to-rebase &&
 
-	echo b > a &&
-	git commit -a -m b &&
-	echo c > a &&
-	git commit -a -m c &&
+	test_commit --annotate b a b &&
+	test_commit --annotate c a c &&
 
 	git checkout to-rebase &&
-	echo d > a &&
-	git commit -a -m "merge should fail on this" &&
-	echo e > a &&
-	git commit -a -m "merge should fail on this, too" &&
-	git branch pre-rebase
+	test_commit "merge should fail on this" a d d &&
+	test_commit --annotate "merge should fail on this, too" a e pre-rebase
 '
 
+# Check that HEAD is equal to "pre-rebase" and the current branch is
+# "to-rebase"
+check_head() {
+	test_cmp_rev HEAD pre-rebase^{commit} &&
+	test "$(git symbolic-ref HEAD)" = refs/heads/to-rebase
+}
+
 testrebase() {
 	type=$1
-	dotest=$2
+	state_dir=$2
 
 	test_expect_success "rebase$type --abort" '
-		cd "$work_dir" &&
 		# Clean up the state from the previous one
 		git reset --hard pre-rebase &&
 		test_must_fail git rebase$type main &&
-		test_path_is_dir "$dotest" &&
+		test_path_is_dir "$state_dir" &&
 		git rebase --abort &&
-		test $(git rev-parse to-rebase) = $(git rev-parse pre-rebase) &&
-		test ! -d "$dotest"
+		check_head &&
+		test_path_is_missing "$state_dir"
 	'
 
 	test_expect_success "rebase$type --abort after --skip" '
-		cd "$work_dir" &&
 		# Clean up the state from the previous one
 		git reset --hard pre-rebase &&
 		test_must_fail git rebase$type main &&
-		test_path_is_dir "$dotest" &&
+		test_path_is_dir "$state_dir" &&
 		test_must_fail git rebase --skip &&
-		test $(git rev-parse HEAD) = $(git rev-parse main) &&
+		test_cmp_rev HEAD main &&
 		git rebase --abort &&
-		test $(git rev-parse to-rebase) = $(git rev-parse pre-rebase) &&
-		test ! -d "$dotest"
+		check_head &&
+		test_path_is_missing "$state_dir"
 	'
 
 	test_expect_success "rebase$type --abort after --continue" '
-		cd "$work_dir" &&
 		# Clean up the state from the previous one
 		git reset --hard pre-rebase &&
 		test_must_fail git rebase$type main &&
-		test_path_is_dir "$dotest" &&
+		test_path_is_dir "$state_dir" &&
 		echo c > a &&
 		echo d >> a &&
 		git add a &&
 		test_must_fail git rebase --continue &&
-		test $(git rev-parse HEAD) != $(git rev-parse main) &&
+		test_cmp_rev ! HEAD main &&
 		git rebase --abort &&
-		test $(git rev-parse to-rebase) = $(git rev-parse pre-rebase) &&
-		test ! -d "$dotest"
+		check_head &&
+		test_path_is_missing "$state_dir"
+	'
+
+	test_expect_success "rebase$type --abort when checking out a tag" '
+		test_when_finished "git symbolic-ref HEAD refs/heads/to-rebase" &&
+		git reset --hard a -- &&
+		test_must_fail git rebase$type --onto b c pre-rebase &&
+		test_cmp_rev HEAD b^{commit} &&
+		git rebase --abort &&
+		test_cmp_rev HEAD pre-rebase^{commit} &&
+		! git symbolic-ref HEAD
 	'
 
 	test_expect_success "rebase$type --abort does not update reflog" '
-		cd "$work_dir" &&
 		# Clean up the state from the previous one
 		git reset --hard pre-rebase &&
 		git reflog show to-rebase > reflog_before &&
@@ -89,7 +89,6 @@
 	'
 
 	test_expect_success 'rebase --abort can not be used with other options' '
-		cd "$work_dir" &&
 		# Clean up the state from the previous one
 		git reset --hard pre-rebase &&
 		test_must_fail git rebase$type main &&
@@ -97,33 +96,21 @@
 		test_must_fail git rebase --abort -v &&
 		git rebase --abort
 	'
+
+	test_expect_success "rebase$type --quit" '
+		test_when_finished "git symbolic-ref HEAD refs/heads/to-rebase" &&
+		# Clean up the state from the previous one
+		git reset --hard pre-rebase &&
+		test_must_fail git rebase$type main &&
+		test_path_is_dir $state_dir &&
+		head_before=$(git rev-parse HEAD) &&
+		git rebase --quit &&
+		test_cmp_rev HEAD $head_before &&
+		test_path_is_missing .git/rebase-apply
+	'
 }
 
 testrebase " --apply" .git/rebase-apply
 testrebase " --merge" .git/rebase-merge
 
-test_expect_success 'rebase --apply --quit' '
-	cd "$work_dir" &&
-	# Clean up the state from the previous one
-	git reset --hard pre-rebase &&
-	test_must_fail git rebase --apply main &&
-	test_path_is_dir .git/rebase-apply &&
-	head_before=$(git rev-parse HEAD) &&
-	git rebase --quit &&
-	test $(git rev-parse HEAD) = $head_before &&
-	test ! -d .git/rebase-apply
-'
-
-test_expect_success 'rebase --merge --quit' '
-	cd "$work_dir" &&
-	# Clean up the state from the previous one
-	git reset --hard pre-rebase &&
-	test_must_fail git rebase --merge main &&
-	test_path_is_dir .git/rebase-merge &&
-	head_before=$(git rev-parse HEAD) &&
-	git rebase --quit &&
-	test $(git rev-parse HEAD) = $head_before &&
-	test ! -d .git/rebase-merge
-'
-
 test_done
diff --git a/t/t3408-rebase-multi-line.sh b/t/t3408-rebase-multi-line.sh
index ab0960e..cde3562 100755
--- a/t/t3408-rebase-multi-line.sh
+++ b/t/t3408-rebase-multi-line.sh
@@ -55,14 +55,4 @@
 	test_cmp expect actual
 
 '
-test_expect_success REBASE_P rebasep '
-
-	git checkout side-merge &&
-	git rebase -p side &&
-	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
-	git cat-file commit side-merge-original | sed -e "1,/^\$/d" >expect &&
-	test_cmp expect actual
-
-'
-
 test_done
diff --git a/t/t3409-rebase-preserve-merges.sh b/t/t3409-rebase-preserve-merges.sh
deleted file mode 100755
index ec8062a..0000000
--- a/t/t3409-rebase-preserve-merges.sh
+++ /dev/null
@@ -1,130 +0,0 @@
-#!/bin/sh
-#
-# Copyright(C) 2008 Stephen Habermann & Andreas Ericsson
-#
-test_description='git rebase -p should preserve merges
-
-Run "git rebase -p" and check that merges are properly carried along
-'
-GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
-export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
-
-. ./test-lib.sh
-
-if ! test_have_prereq REBASE_P; then
-	skip_all='skipping git rebase -p tests, as asked for'
-	test_done
-fi
-
-GIT_AUTHOR_EMAIL=bogus_email_address
-export GIT_AUTHOR_EMAIL
-
-# Clone 2 (conflicting merge):
-#
-# A1--A2--B3   <-- origin/main
-#  \       \
-#   B1------M  <-- topic
-#    \
-#     B2       <-- origin/topic
-#
-# Clone 3 (no-ff merge):
-#
-# A1--A2--B3   <-- origin/main
-#  \
-#   B1------M  <-- topic
-#    \     /
-#     \--A3    <-- topic2
-#      \
-#       B2     <-- origin/topic
-#
-# Clone 4 (same as Clone 3)
-
-test_expect_success 'setup for merge-preserving rebase' \
-	'echo First > A &&
-	git add A &&
-	git commit -m "Add A1" &&
-	git checkout -b topic &&
-	echo Second > B &&
-	git add B &&
-	git commit -m "Add B1" &&
-	git checkout -f main &&
-	echo Third >> A &&
-	git commit -a -m "Modify A2" &&
-	echo Fifth > B &&
-	git add B &&
-	git commit -m "Add different B" &&
-
-	git clone ./. clone2 &&
-	(
-		cd clone2 &&
-		git checkout -b topic origin/topic &&
-		test_must_fail git merge origin/main &&
-		echo Resolved >B &&
-		git add B &&
-		git commit -m "Merge origin/main into topic"
-	) &&
-
-	git clone ./. clone3 &&
-	(
-		cd clone3 &&
-		git checkout -b topic2 origin/topic &&
-		echo Sixth > A &&
-		git commit -a -m "Modify A3" &&
-		git checkout -b topic origin/topic &&
-		git merge --no-ff topic2
-	) &&
-
-	git clone ./. clone4 &&
-	(
-		cd clone4 &&
-		git checkout -b topic2 origin/topic &&
-		echo Sixth > A &&
-		git commit -a -m "Modify A3" &&
-		git checkout -b topic origin/topic &&
-		git merge --no-ff topic2
-	) &&
-
-	git checkout topic &&
-	echo Fourth >> B &&
-	git commit -a -m "Modify B2"
-'
-
-test_expect_success '--continue works after a conflict' '
-	(
-	cd clone2 &&
-	git fetch &&
-	test_must_fail git rebase -p origin/topic &&
-	test 2 = $(git ls-files B | wc -l) &&
-	echo Resolved again > B &&
-	test_must_fail git rebase --continue &&
-	grep "^@@@ " .git/rebase-merge/patch &&
-	git add B &&
-	git rebase --continue &&
-	test 1 = $(git rev-list --all --pretty=oneline | grep "Modify A" | wc -l) &&
-	test 1 = $(git rev-list --all --pretty=oneline | grep "Add different" | wc -l) &&
-	test 1 = $(git rev-list --all --pretty=oneline | grep "Merge origin" | wc -l)
-	)
-'
-
-test_expect_success 'rebase -p preserves no-ff merges' '
-	(
-	cd clone3 &&
-	git fetch &&
-	git rebase -p origin/topic &&
-	test 3 = $(git rev-list --all --pretty=oneline | grep "Modify A" | wc -l) &&
-	test 1 = $(git rev-list --all --pretty=oneline | grep "Merge branch" | wc -l)
-	)
-'
-
-test_expect_success 'rebase -p ignores merge.log config' '
-	(
-	cd clone4 &&
-	git fetch &&
-	git -c merge.log=1 rebase -p origin/topic &&
-	echo >expected &&
-	git log --format="%b" -1 >current &&
-	test_cmp expected current
-	)
-'
-
-test_done
diff --git a/t/t3410-rebase-preserve-dropped-merges.sh b/t/t3410-rebase-preserve-dropped-merges.sh
deleted file mode 100755
index 2e29866..0000000
--- a/t/t3410-rebase-preserve-dropped-merges.sh
+++ /dev/null
@@ -1,90 +0,0 @@
-#!/bin/sh
-#
-# Copyright (c) 2008 Stephen Haberman
-#
-
-test_description='git rebase preserve merges
-
-This test runs git rebase with preserve merges and ensures commits
-dropped by the --cherry-pick flag have their childrens parents
-rewritten.
-'
-. ./test-lib.sh
-
-if ! test_have_prereq REBASE_P; then
-	skip_all='skipping git rebase -p tests, as asked for'
-	test_done
-fi
-
-# set up two branches like this:
-#
-# A - B - C - D - E
-#   \
-#     F - G - H
-#       \
-#         I
-#
-# where B, D and G touch the same file.
-
-test_expect_success 'setup' '
-	test_commit A file1 &&
-	test_commit B file1 1 &&
-	test_commit C file2 &&
-	test_commit D file1 2 &&
-	test_commit E file3 &&
-	git checkout A &&
-	test_commit F file4 &&
-	test_commit G file1 3 &&
-	test_commit H file5 &&
-	git checkout F &&
-	test_commit I file6
-'
-
-# A - B - C - D - E
-#   \             \ \
-#     F - G - H -- L \        -->   L
-#       \            |               \
-#         I -- G2 -- J -- K           I -- K
-# G2 = same changes as G
-test_expect_success 'skip same-resolution merges with -p' '
-	git checkout H &&
-	test_must_fail git merge E &&
-	test_commit L file1 23 &&
-	git checkout I &&
-	test_commit G2 file1 3 &&
-	test_must_fail git merge E &&
-	test_commit J file1 23 &&
-	test_commit K file7 file7 &&
-	git rebase -i -p L &&
-	test $(git rev-parse HEAD^^) = $(git rev-parse L) &&
-	test "23" = "$(cat file1)" &&
-	test "I" = "$(cat file6)" &&
-	test "file7" = "$(cat file7)"
-'
-
-# A - B - C - D - E
-#   \             \ \
-#     F - G - H -- L2 \        -->   L2
-#       \             |                \
-#         I -- G3 --- J2 -- K2           I -- G3 -- K2
-# G2 = different changes as G
-test_expect_success 'keep different-resolution merges with -p' '
-	git checkout H &&
-	test_must_fail git merge E &&
-	test_commit L2 file1 23 &&
-	git checkout I &&
-	test_commit G3 file1 4 &&
-	test_must_fail git merge E &&
-	test_commit J2 file1 24 &&
-	test_commit K2 file7 file7 &&
-	test_must_fail git rebase -i -p L2 &&
-	echo 234 > file1 &&
-	git add file1 &&
-	git rebase --continue &&
-	test $(git rev-parse HEAD^^^) = $(git rev-parse L2) &&
-	test "234" = "$(cat file1)" &&
-	test "I" = "$(cat file6)" &&
-	test "file7" = "$(cat file7)"
-'
-
-test_done
diff --git a/t/t3411-rebase-preserve-around-merges.sh b/t/t3411-rebase-preserve-around-merges.sh
deleted file mode 100755
index fb45e7b..0000000
--- a/t/t3411-rebase-preserve-around-merges.sh
+++ /dev/null
@@ -1,80 +0,0 @@
-#!/bin/sh
-#
-# Copyright (c) 2008 Stephen Haberman
-#
-
-test_description='git rebase preserve merges
-
-This test runs git rebase with -p and tries to squash a commit from after
-a merge to before the merge.
-'
-. ./test-lib.sh
-
-if ! test_have_prereq REBASE_P; then
-	skip_all='skipping git rebase -p tests, as asked for'
-	test_done
-fi
-
-. "$TEST_DIRECTORY"/lib-rebase.sh
-
-set_fake_editor
-
-# set up two branches like this:
-#
-# A1 - B1 - D1 - E1 - F1
-#       \        /
-#        -- C1 --
-
-test_expect_success 'setup' '
-	test_commit A1 &&
-	test_commit B1 &&
-	test_commit C1 &&
-	git reset --hard B1 &&
-	test_commit D1 &&
-	test_merge E1 C1 &&
-	test_commit F1
-'
-
-# Should result in:
-#
-# A1 - B1 - D2 - E2
-#       \        /
-#        -- C1 --
-#
-test_expect_success 'squash F1 into D1' '
-	FAKE_LINES="1 squash 4 2 3" git rebase -i -p B1 &&
-	test "$(git rev-parse HEAD^2)" = "$(git rev-parse C1)" &&
-	test "$(git rev-parse HEAD~2)" = "$(git rev-parse B1)" &&
-	git tag E2
-'
-
-# Start with:
-#
-# A1 - B1 - D2 - E2
-#  \
-#   G1 ---- L1 ---- M1
-#    \             /
-#     H1 -- J1 -- K1
-#      \         /
-#        -- I1 --
-#
-# And rebase G1..M1 onto E2
-
-test_expect_success 'rebase two levels of merge' '
-	git checkout A1 &&
-	test_commit G1 &&
-	test_commit H1 &&
-	test_commit I1 &&
-	git checkout -b branch3 H1 &&
-	test_commit J1 &&
-	test_merge K1 I1 &&
-	git checkout -b branch2 G1 &&
-	test_commit L1 &&
-	test_merge M1 K1 &&
-	GIT_EDITOR=: git rebase -i -p E2 &&
-	test "$(git rev-parse HEAD~3)" = "$(git rev-parse E2)" &&
-	test "$(git rev-parse HEAD~2)" = "$(git rev-parse HEAD^2^2~2)" &&
-	test "$(git rev-parse HEAD^2^1^1)" = "$(git rev-parse HEAD^2^2^1)"
-'
-
-test_done
diff --git a/t/t3412-rebase-root.sh b/t/t3412-rebase-root.sh
index fda62c6..19c6f4a 100755
--- a/t/t3412-rebase-root.sh
+++ b/t/t3412-rebase-root.sh
@@ -89,17 +89,6 @@
 	test "z$(cat .git/PRE-REBASE-INPUT)" = z--root,work4
 '
 
-test_expect_success REBASE_P 'rebase -i -p with linear history' '
-	git checkout -b work5 other &&
-	git rebase -i -p --root --onto main &&
-	git log --pretty=tformat:"%s" > rebased5 &&
-	test_cmp expect rebased5
-'
-
-test_expect_success REBASE_P 'pre-rebase got correct input (5)' '
-	test "z$(cat .git/PRE-REBASE-INPUT)" = z--root,
-'
-
 test_expect_success 'set up merge history' '
 	git checkout other^ &&
 	git checkout -b side &&
@@ -123,13 +112,6 @@
 1
 EOF
 
-test_expect_success REBASE_P 'rebase -i -p with merge' '
-	git checkout -b work6 other &&
-	git rebase -i -p --root --onto main &&
-	log_with_names work6 > rebased6 &&
-	test_cmp expect-side rebased6
-'
-
 test_expect_success 'set up second root and merge' '
 	git symbolic-ref HEAD refs/heads/third &&
 	rm .git/index &&
@@ -158,13 +140,6 @@
 1
 EOF
 
-test_expect_success REBASE_P 'rebase -i -p with two roots' '
-	git checkout -b work7 other &&
-	git rebase -i -p --root --onto main &&
-	log_with_names work7 > rebased7 &&
-	test_cmp expect-third rebased7
-'
-
 test_expect_success 'setup pre-rebase hook that fails' '
 	mkdir -p .git/hooks &&
 	cat >.git/hooks/pre-rebase <<EOF &&
@@ -264,21 +239,9 @@
 1
 EOF
 
-test_expect_success REBASE_P 'rebase -i -p --root with conflict (first part)' '
-	git checkout -b conflict3 other &&
-	test_must_fail git rebase -i -p --root --onto main &&
-	git ls-files -u | grep "B$"
-'
-
 test_expect_success 'fix the conflict' '
 	echo 3 > B &&
 	git add B
 '
 
-test_expect_success REBASE_P 'rebase -i -p --root with conflict (second part)' '
-	git rebase --continue &&
-	log_with_names conflict3 >out &&
-	test_cmp expect-conflict-p out
-'
-
 test_done
diff --git a/t/t3414-rebase-preserve-onto.sh b/t/t3414-rebase-preserve-onto.sh
deleted file mode 100755
index 72e04b5..0000000
--- a/t/t3414-rebase-preserve-onto.sh
+++ /dev/null
@@ -1,85 +0,0 @@
-#!/bin/sh
-#
-# Copyright (c) 2009 Greg Price
-#
-
-test_description='git rebase -p should respect --onto
-
-In a rebase with --onto, we should rewrite all the commits that
-aren'"'"'t on top of $ONTO, even if they are on top of $UPSTREAM.
-'
-. ./test-lib.sh
-
-if ! test_have_prereq REBASE_P; then
-	skip_all='skipping git rebase -p tests, as asked for'
-	test_done
-fi
-
-. "$TEST_DIRECTORY"/lib-rebase.sh
-
-# Set up branches like this:
-# A1---B1---E1---F1---G1
-#  \    \             /
-#   \    \--C1---D1--/
-#    H1
-
-test_expect_success 'setup' '
-	test_commit A1 &&
-	test_commit B1 &&
-	test_commit C1 &&
-	test_commit D1 &&
-	git reset --hard B1 &&
-	test_commit E1 &&
-	test_commit F1 &&
-	test_merge G1 D1 &&
-	git reset --hard A1 &&
-	test_commit H1
-'
-
-# Now rebase merge G1 from both branches' base B1, both should move:
-# A1---B1---E1---F1---G1
-#  \    \             /
-#   \    \--C1---D1--/
-#    \
-#     H1---E2---F2---G2
-#      \             /
-#       \--C2---D2--/
-
-test_expect_success 'rebase from B1 onto H1' '
-	git checkout G1 &&
-	git rebase -p --onto H1 B1 &&
-	test "$(git rev-parse HEAD^1^1^1)" = "$(git rev-parse H1)" &&
-	test "$(git rev-parse HEAD^2^1^1)" = "$(git rev-parse H1)"
-'
-
-# On the other hand if rebase from E1 which is within one branch,
-# then the other branch stays:
-# A1---B1---E1---F1---G1
-#  \    \             /
-#   \    \--C1---D1--/
-#    \             \
-#     H1-----F3-----G3
-
-test_expect_success 'rebase from E1 onto H1' '
-	git checkout G1 &&
-	git rebase -p --onto H1 E1 &&
-	test "$(git rev-parse HEAD^1^1)" = "$(git rev-parse H1)" &&
-	test "$(git rev-parse HEAD^2)" = "$(git rev-parse D1)"
-'
-
-# And the same if we rebase from a commit in the second-parent branch.
-# A1---B1---E1---F1----G1
-#  \    \          \   /
-#   \    \--C1---D1-\-/
-#    \               \
-#     H1------D3------G4
-
-test_expect_success 'rebase from C1 onto H1' '
-	git checkout G1 &&
-	git rev-list --first-parent --pretty=oneline C1..G1 &&
-	git rebase -p --onto H1 C1 &&
-	test "$(git rev-parse HEAD^2^1)" = "$(git rev-parse H1)" &&
-	test "$(git rev-parse HEAD^1)" = "$(git rev-parse F1)"
-'
-
-test_done
diff --git a/t/t3418-rebase-continue.sh b/t/t3418-rebase-continue.sh
index 738fbae..22eca73 100755
--- a/t/t3418-rebase-continue.sh
+++ b/t/t3418-rebase-continue.sh
@@ -119,20 +119,6 @@
 	test -f funny.was.run
 '
 
-test_expect_success REBASE_P 'rebase passes merge strategy options correctly' '
-	rm -fr .git/rebase-* &&
-	git reset --hard commit-new-file-F3-on-topic-branch &&
-	test_commit theirs-to-merge &&
-	git reset --hard HEAD^ &&
-	test_commit some-commit &&
-	test_tick &&
-	git merge --no-ff theirs-to-merge &&
-	FAKE_LINES="1 edit 2 3" git rebase -i -f -p -m \
-		-s recursive --strategy-option=theirs HEAD~2 &&
-	test_commit force-change &&
-	git rebase --continue
-'
-
 test_expect_success 'rebase -r passes merge strategy options correctly' '
 	rm -fr .git/rebase-* &&
 	git reset --hard commit-new-file-F3-on-topic-branch &&
@@ -268,7 +254,6 @@
 test_rerere_autoupdate -m
 GIT_SEQUENCE_EDITOR=: && export GIT_SEQUENCE_EDITOR
 test_rerere_autoupdate -i
-test_have_prereq !REBASE_P || test_rerere_autoupdate --preserve-merges
 unset GIT_SEQUENCE_EDITOR
 
 test_expect_success 'the todo command "break" works' '
diff --git a/t/t3421-rebase-topology-linear.sh b/t/t3421-rebase-topology-linear.sh
index 4a9204b..62d86d5 100755
--- a/t/t3421-rebase-topology-linear.sh
+++ b/t/t3421-rebase-topology-linear.sh
@@ -29,7 +29,6 @@
 test_run_rebase success --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 test_expect_success 'setup branches and remote tracking' '
 	git tag -l >tags &&
@@ -53,7 +52,6 @@
 test_run_rebase success --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 test_run_rebase () {
 	result=$1
@@ -70,7 +68,6 @@
 test_run_rebase success --fork-point
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase failure -p
 
 test_run_rebase () {
 	result=$1
@@ -87,7 +84,6 @@
 test_run_rebase success --fork-point
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 test_run_rebase () {
 	result=$1
@@ -102,7 +98,6 @@
 test_run_rebase success --fork-point
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 #       f
 #      /
@@ -142,7 +137,6 @@
 test_run_rebase success --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 test_run_rebase () {
 	result=$1
@@ -157,7 +151,6 @@
 test_run_rebase success --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 test_run_rebase () {
 	result=$1
@@ -172,7 +165,6 @@
 test_run_rebase success --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 test_run_rebase () {
 	result=$1
@@ -187,7 +179,6 @@
 test_run_rebase success --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 # a---b---c---j!
 #      \
@@ -215,7 +206,6 @@
 test_run_rebase failure --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase failure -p
 
 test_run_rebase () {
 	result=$1
@@ -229,7 +219,6 @@
 }
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 test_run_rebase () {
 	result=$1
@@ -243,7 +232,6 @@
 }
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 test_run_rebase success --rebase-merges
 
 #       m
@@ -283,7 +271,6 @@
 test_run_rebase success --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 test_run_rebase () {
 	result=$1
@@ -298,7 +285,6 @@
 test_run_rebase success --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase failure -p
 
 test_run_rebase () {
 	result=$1
@@ -313,7 +299,6 @@
 test_run_rebase success --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 test_run_rebase () {
 	result=$1
@@ -329,7 +314,6 @@
 test_run_rebase success --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase failure -p
 
 test_run_rebase () {
 	result=$1
@@ -344,7 +328,6 @@
 test_run_rebase success --apply
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase failure -p
 
 test_run_rebase () {
 	result=$1
@@ -358,7 +341,6 @@
 test_run_rebase success ''
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase failure -p
 
 test_run_rebase () {
 	result=$1
@@ -373,6 +355,5 @@
 test_run_rebase success ''
 test_run_rebase success -m
 test_run_rebase success -i
-test_have_prereq !REBASE_P || test_run_rebase success -p
 
 test_done
diff --git a/t/t3422-rebase-incompatible-options.sh b/t/t3422-rebase-incompatible-options.sh
index c823406..eb0a3d9 100755
--- a/t/t3422-rebase-incompatible-options.sh
+++ b/t/t3422-rebase-incompatible-options.sh
@@ -63,15 +63,4 @@
 test_rebase_am_only --whitespace=fix
 test_rebase_am_only -C4
 
-test_expect_success REBASE_P '--preserve-merges incompatible with --signoff' '
-	git checkout B^0 &&
-	test_must_fail git rebase --preserve-merges --signoff A
-'
-
-test_expect_success REBASE_P \
-	'--preserve-merges incompatible with --rebase-merges' '
-	git checkout B^0 &&
-	test_must_fail git rebase --preserve-merges --rebase-merges A
-'
-
 test_done
diff --git a/t/t3425-rebase-topology-merges.sh b/t/t3425-rebase-topology-merges.sh
index e42faa4..63acc1e 100755
--- a/t/t3425-rebase-topology-merges.sh
+++ b/t/t3425-rebase-topology-merges.sh
@@ -106,155 +106,4 @@
 test_run_rebase success 'd n o e' -m
 test_run_rebase success 'd n o e' -i
 
-if ! test_have_prereq REBASE_P; then
-	skip_all='skipping git rebase -p tests, as asked for'
-	test_done
-fi
-
-test_expect_success "rebase -p is no-op in non-linear history" "
-	reset_rebase &&
-	git rebase -p d w &&
-	test_cmp_rev w HEAD
-"
-
-test_expect_success "rebase -p is no-op when base inside second parent" "
-	reset_rebase &&
-	git rebase -p e w &&
-	test_cmp_rev w HEAD
-"
-
-test_expect_failure "rebase -p --root on non-linear history is a no-op" "
-	reset_rebase &&
-	git rebase -p --root w &&
-	test_cmp_rev w HEAD
-"
-
-test_expect_success "rebase -p re-creates merge from side branch" "
-	reset_rebase &&
-	git rebase -p z w &&
-	test_cmp_rev z HEAD^ &&
-	test_cmp_rev w^2 HEAD^2
-"
-
-test_expect_success "rebase -p re-creates internal merge" "
-	reset_rebase &&
-	git rebase -p c w &&
-	test_cmp_rev c HEAD~4 &&
-	test_cmp_rev HEAD^2^ HEAD~3 &&
-	test_revision_subjects 'd n e o w' HEAD~3 HEAD~2 HEAD^2 HEAD^ HEAD
-"
-
-test_expect_success "rebase -p can re-create two branches on onto" "
-	reset_rebase &&
-	git rebase -p --onto c d w &&
-	test_cmp_rev c HEAD~3 &&
-	test_cmp_rev c HEAD^2^ &&
-	test_revision_subjects 'n e o w' HEAD~2 HEAD^2 HEAD^ HEAD
-"
-
-#       f
-#      /
-# a---b---c---g---h
-#      \
-#       d---gp--i
-#        \       \
-#         e-------u
-#
-# gp = cherry-picked g
-# h = reverted g
-test_expect_success 'setup of non-linear-history for patch-equivalence tests' '
-	git checkout e &&
-	test_merge u i
-'
-
-test_expect_success "rebase -p re-creates history around dropped commit matching upstream" "
-	reset_rebase &&
-	git rebase -p h u &&
-	test_cmp_rev h HEAD~3 &&
-	test_cmp_rev HEAD^2^ HEAD~2 &&
-	test_revision_subjects 'd i e u' HEAD~2 HEAD^2 HEAD^ HEAD
-"
-
-test_expect_success "rebase -p --onto in merged history drops patches in upstream" "
-	reset_rebase &&
-	git rebase -p --onto f h u &&
-	test_cmp_rev f HEAD~3 &&
-	test_cmp_rev HEAD^2^ HEAD~2 &&
-	test_revision_subjects 'd i e u' HEAD~2 HEAD^2 HEAD^ HEAD
-"
-
-test_expect_success "rebase -p --onto in merged history does not drop patches in onto" "
-	reset_rebase &&
-	git rebase -p --onto h f u &&
-	test_cmp_rev h HEAD~3 &&
-	test_cmp_rev HEAD^2~2 HEAD~2 &&
-	test_revision_subjects 'd gp i e u' HEAD~2 HEAD^2^ HEAD^2 HEAD^ HEAD
-"
-
-# a---b---c---g---h
-#      \
-#       d---gp--s
-#        \   \ /
-#         \   X
-#          \ / \
-#           e---t
-#
-# gp = cherry-picked g
-# h = reverted g
-test_expect_success 'setup of non-linear-history for dropping whole side' '
-	git checkout gp &&
-	test_merge s e &&
-	git checkout e &&
-	test_merge t gp
-'
-
-test_expect_failure "rebase -p drops merge commit when entire first-parent side is dropped" "
-	reset_rebase &&
-	git rebase -p h s &&
-	test_cmp_rev h HEAD~2 &&
-	test_linear_range 'd e' h..
-"
-
-test_expect_success "rebase -p drops merge commit when entire second-parent side is dropped" "
-	reset_rebase &&
-	git rebase -p h t &&
-	test_cmp_rev h HEAD~2 &&
-	test_linear_range 'd e' h..
-"
-
-# a---b---c
-#      \
-#       d---e
-#        \   \
-#         n---r
-#          \
-#           o
-#
-# r = tree-same with n
-test_expect_success 'setup of non-linear-history for empty commits' '
-	git checkout n &&
-	git merge --no-commit e &&
-	git reset n . &&
-	git commit -m r &&
-	git reset --hard &&
-	git clean -f &&
-	git tag r
-'
-
-test_expect_success "rebase -p re-creates empty internal merge commit" "
-	reset_rebase &&
-	git rebase -p c r &&
-	test_cmp_rev c HEAD~3 &&
-	test_cmp_rev HEAD^2^ HEAD~2 &&
-	test_revision_subjects 'd e n r' HEAD~2 HEAD^2 HEAD^ HEAD
-"
-
-test_expect_success "rebase -p re-creates empty merge commit" "
-	reset_rebase &&
-	git rebase -p o r &&
-	test_cmp_rev e HEAD^2 &&
-	test_cmp_rev o HEAD^ &&
-	test_revision_subjects 'r' HEAD
-"
-
 test_done
diff --git a/t/t3427-rebase-subtree.sh b/t/t3427-rebase-subtree.sh
index e78c7e3..48b76f8 100755
--- a/t/t3427-rebase-subtree.sh
+++ b/t/t3427-rebase-subtree.sh
@@ -36,11 +36,10 @@
 # where the root commit adds three files: topic_1.t, topic_2.t and topic_3.t.
 #
 # This commit history is then rebased onto `topic_3` with the
-# `-Xsubtree=files_subtree` option in three different ways:
+# `-Xsubtree=files_subtree` option in two different ways:
 #
-# 1. using `--preserve-merges`
-# 2. using `--preserve-merges` and --keep-empty
-# 3. without specifying a rebase backend
+# 1. without specifying a rebase backend
+# 2. using the `--rebase-merges` backend
 
 test_expect_success 'setup' '
 	test_commit README &&
@@ -69,25 +68,6 @@
 	git commit -m "Empty commit" --allow-empty
 '
 
-# FAILURE: Does not preserve topic_4.
-test_expect_failure REBASE_P 'Rebase -Xsubtree --preserve-merges --onto commit' '
-	reset_rebase &&
-	git checkout -b rebase-preserve-merges to-rebase &&
-	git rebase -Xsubtree=files_subtree --preserve-merges --onto files-main main &&
-	verbose test "$(commit_message HEAD~)" = "topic_4" &&
-	verbose test "$(commit_message HEAD)" = "files_subtree/topic_5"
-'
-
-# FAILURE: Does not preserve topic_4.
-test_expect_failure REBASE_P 'Rebase -Xsubtree --keep-empty --preserve-merges --onto commit' '
-	reset_rebase &&
-	git checkout -b rebase-keep-empty to-rebase &&
-	git rebase -Xsubtree=files_subtree --keep-empty --preserve-merges --onto files-main main &&
-	verbose test "$(commit_message HEAD~2)" = "topic_4" &&
-	verbose test "$(commit_message HEAD~)" = "files_subtree/topic_5" &&
-	verbose test "$(commit_message HEAD)" = "Empty commit"
-'
-
 test_expect_success 'Rebase -Xsubtree --empty=ask --onto commit' '
 	reset_rebase &&
 	git checkout -b rebase-onto to-rebase &&
diff --git a/t/t3435-rebase-gpg-sign.sh b/t/t3435-rebase-gpg-sign.sh
index ec10766..5f8ba2c 100755
--- a/t/t3435-rebase-gpg-sign.sh
+++ b/t/t3435-rebase-gpg-sign.sh
@@ -65,6 +65,7 @@
 test_rebase_gpg_sign   false -i --no-gpg-sign --gpg-sign
 
 test_expect_failure 'rebase -p --no-gpg-sign override commit.gpgsign' '
+	test_when_finished "git clean -f" &&
 	git reset --hard merged &&
 	git config commit.gpgsign true &&
 	git rebase -p --no-gpg-sign --onto=one fork-point main &&
diff --git a/t/t3501-revert-cherry-pick.sh b/t/t3501-revert-cherry-pick.sh
index 9d100cd..4b5b607 100755
--- a/t/t3501-revert-cherry-pick.sh
+++ b/t/t3501-revert-cherry-pick.sh
@@ -158,4 +158,20 @@
 	grep -q "^modified$" renamed
 '
 
+test_expect_success 'advice from failed revert' '
+	test_commit --no-tag "add dream" dream dream &&
+	dream_oid=$(git rev-parse --short HEAD) &&
+	cat <<-EOF >expected &&
+	error: could not revert $dream_oid... add dream
+	hint: After resolving the conflicts, mark them with
+	hint: "git add/rm <pathspec>", then run
+	hint: "git revert --continue".
+	hint: You can instead skip this commit with "git revert --skip".
+	hint: To abort and get back to the state before "git revert",
+	hint: run "git revert --abort".
+	EOF
+	test_commit --append --no-tag "double-add dream" dream dream &&
+	test_must_fail git revert HEAD^ 2>actual &&
+	test_cmp expected actual
+'
 test_done
diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
index 014001b..979e843 100755
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -47,20 +47,23 @@
 	test "$head" = "$newhead"
 '
 
-test_expect_success 'advice from failed cherry-pick' "
+test_expect_success 'advice from failed cherry-pick' '
 	pristine_detach initial &&
 
-	picked=\$(git rev-parse --short picked) &&
+	picked=$(git rev-parse --short picked) &&
 	cat <<-EOF >expected &&
-	error: could not apply \$picked... picked
-	hint: after resolving the conflicts, mark the corrected paths
-	hint: with 'git add <paths>' or 'git rm <paths>'
-	hint: and commit the result with 'git commit'
+	error: could not apply $picked... picked
+	hint: After resolving the conflicts, mark them with
+	hint: "git add/rm <pathspec>", then run
+	hint: "git cherry-pick --continue".
+	hint: You can instead skip this commit with "git cherry-pick --skip".
+	hint: To abort and get back to the state before "git cherry-pick",
+	hint: run "git cherry-pick --abort".
 	EOF
 	test_must_fail git cherry-pick picked 2>actual &&
 
 	test_cmp expected actual
-"
+'
 
 test_expect_success 'advice from failed cherry-pick --no-commit' "
 	pristine_detach initial &&
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index 49010aa..3b0fa66 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -238,6 +238,7 @@
 '
 
 test_expect_success 'allow skipping stopped cherry-pick because of untracked file modifications' '
+	test_when_finished "rm unrelated" &&
 	pristine_detach initial &&
 	git rm --cached unrelated &&
 	git commit -m "untrack unrelated" &&
diff --git a/t/t3601-rm-pathspec-file.sh b/t/t3601-rm-pathspec-file.sh
index 7de21f8..b2a8db6 100755
--- a/t/t3601-rm-pathspec-file.sh
+++ b/t/t3601-rm-pathspec-file.sh
@@ -2,6 +2,7 @@
 
 test_description='rm --pathspec-from-file'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_tick
diff --git a/t/t3602-rm-sparse-checkout.sh b/t/t3602-rm-sparse-checkout.sh
index e9e9a15..034ec01 100755
--- a/t/t3602-rm-sparse-checkout.sh
+++ b/t/t3602-rm-sparse-checkout.sh
@@ -11,12 +11,15 @@
 	git commit -m files &&
 
 	cat >sparse_error_header <<-EOF &&
-	The following pathspecs didn't match any eligible path, but they do match index
-	entries outside the current sparse checkout:
+	The following paths and/or pathspecs matched paths that exist
+	outside of your sparse-checkout definition, so will not be
+	updated in the index:
 	EOF
 
 	cat >sparse_hint <<-EOF &&
-	hint: Disable or modify the sparsity rules if you intend to update such entries.
+	hint: If you intend to update such entries, try one of the following:
+	hint: * Use the --sparse option.
+	hint: * Disable or modify the sparsity rules.
 	hint: Disable this message with \"git config advice.updateSparsePath false\"
 	EOF
 
@@ -39,7 +42,29 @@
 	git sparse-checkout set sub/dir &&
 	git rm -r sub &&
 	git status --porcelain -uno >actual &&
-	echo "D  sub/dir/e" >expected &&
+	cat >expected <<-\EOF &&
+	D  sub/dir/e
+	EOF
+	test_cmp expected actual &&
+
+	git rm --sparse -r sub &&
+	git status --porcelain -uno >actual2 &&
+	cat >expected2 <<-\EOF &&
+	D  sub/d
+	D  sub/dir/e
+	EOF
+	test_cmp expected2 actual2
+'
+
+test_expect_success 'recursive rm --sparse removes sparse entries' '
+	git reset --hard &&
+	git sparse-checkout set "sub/dir" &&
+	git rm --sparse -r sub &&
+	git status --porcelain -uno >actual &&
+	cat >expected <<-\EOF &&
+	D  sub/d
+	D  sub/dir/e
+	EOF
 	test_cmp expected actual
 '
 
@@ -75,4 +100,40 @@
 	git ls-files --error-unmatch b
 '
 
+test_expect_success 'refuse to rm a non-skip-worktree path outside sparse cone' '
+	git reset --hard &&
+	git sparse-checkout set a &&
+	git update-index --no-skip-worktree b &&
+	test_must_fail git rm b 2>stderr &&
+	test_cmp b_error_and_hint stderr &&
+	git rm --sparse b 2>stderr &&
+	test_must_be_empty stderr &&
+	test_path_is_missing b
+'
+
+test_expect_success 'can remove files from non-sparse dir' '
+	git reset --hard &&
+	git sparse-checkout disable &&
+	mkdir -p w x/y &&
+	test_commit w/f &&
+	test_commit x/y/f &&
+
+	git sparse-checkout set w !/x y/ &&
+	git rm w/f.t x/y/f.t 2>stderr &&
+	test_must_be_empty stderr
+'
+
+test_expect_success 'refuse to remove non-skip-worktree file from sparse dir' '
+	git reset --hard &&
+	git sparse-checkout disable &&
+	mkdir -p x/y/z &&
+	test_commit x/y/z/f &&
+	git sparse-checkout set !/x y/ !x/y/z &&
+
+	git update-index --no-skip-worktree x/y/z/f.t &&
+	test_must_fail git rm x/y/z/f.t 2>stderr &&
+	echo x/y/z/f.t | cat sparse_error_header - sparse_hint >expect &&
+	test_cmp expect stderr
+'
+
 test_done
diff --git a/t/t3700-add.sh b/t/t3700-add.sh
index 4086e1e..283a669 100755
--- a/t/t3700-add.sh
+++ b/t/t3700-add.sh
@@ -5,6 +5,7 @@
 
 test_description='Test of git add, including the -- option.'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # Test the file mode "$1" of the file "$2" in the index.
diff --git a/t/t3705-add-sparse-checkout.sh b/t/t3705-add-sparse-checkout.sh
index 2b1fd0d..f3143c9 100755
--- a/t/t3705-add-sparse-checkout.sh
+++ b/t/t3705-add-sparse-checkout.sh
@@ -19,6 +19,7 @@
 	fi &&
 	git add sparse_entry &&
 	git update-index --skip-worktree sparse_entry &&
+	git commit --allow-empty -m "ensure sparse_entry exists at HEAD" &&
 	SPARSE_ENTRY_BLOB=$(git rev-parse :sparse_entry)
 }
 
@@ -36,14 +37,22 @@
 	EOF
 }
 
+test_sparse_entry_unstaged () {
+	git diff --staged -- sparse_entry >diff &&
+	test_must_be_empty diff
+}
+
 test_expect_success 'setup' "
 	cat >sparse_error_header <<-EOF &&
-	The following pathspecs didn't match any eligible path, but they do match index
-	entries outside the current sparse checkout:
+	The following paths and/or pathspecs matched paths that exist
+	outside of your sparse-checkout definition, so will not be
+	updated in the index:
 	EOF
 
 	cat >sparse_hint <<-EOF &&
-	hint: Disable or modify the sparsity rules if you intend to update such entries.
+	hint: If you intend to update such entries, try one of the following:
+	hint: * Use the --sparse option.
+	hint: * Disable or modify the sparsity rules.
 	hint: Disable this message with \"git config advice.updateSparsePath false\"
 	EOF
 
@@ -55,6 +64,7 @@
 	setup_sparse_entry &&
 	rm sparse_entry &&
 	test_must_fail git add sparse_entry 2>stderr &&
+	test_sparse_entry_unstaged &&
 	test_cmp error_and_hint stderr &&
 	test_sparse_entry_unchanged
 '
@@ -73,6 +83,7 @@
 	rm sparse_entry &&
 	setup_gitignore &&
 	test_must_fail git add . 2>stderr &&
+	test_sparse_entry_unstaged &&
 
 	cat sparse_error_header >expect &&
 	echo . >>expect &&
@@ -88,6 +99,7 @@
 		setup_sparse_entry &&
 		echo modified >sparse_entry &&
 		test_must_fail git add $opt sparse_entry 2>stderr &&
+		test_sparse_entry_unstaged &&
 		test_cmp error_and_hint stderr &&
 		test_sparse_entry_unchanged
 	'
@@ -98,6 +110,7 @@
 	git ls-files --debug sparse_entry | grep mtime >before &&
 	test-tool chmtime -60 sparse_entry &&
 	test_must_fail git add --refresh sparse_entry 2>stderr &&
+	test_sparse_entry_unstaged &&
 	test_cmp error_and_hint stderr &&
 	git ls-files --debug sparse_entry | grep mtime >after &&
 	test_cmp before after
@@ -106,6 +119,7 @@
 test_expect_success 'git add --chmod does not update sparse entries' '
 	setup_sparse_entry &&
 	test_must_fail git add --chmod=+x sparse_entry 2>stderr &&
+	test_sparse_entry_unstaged &&
 	test_cmp error_and_hint stderr &&
 	test_sparse_entry_unchanged &&
 	! test -x sparse_entry
@@ -116,6 +130,7 @@
 	setup_sparse_entry "LINEONE\r\nLINETWO\r\n" &&
 	echo "sparse_entry text=auto" >.gitattributes &&
 	test_must_fail git add --renormalize sparse_entry 2>stderr &&
+	test_sparse_entry_unstaged &&
 	test_cmp error_and_hint stderr &&
 	test_sparse_entry_unchanged
 '
@@ -124,6 +139,7 @@
 	setup_sparse_entry &&
 	rm sparse_entry &&
 	test_must_fail git add --dry-run --ignore-missing sparse_entry 2>stderr &&
+	test_sparse_entry_unstaged &&
 	test_cmp error_and_hint stderr &&
 	test_sparse_entry_unchanged
 '
@@ -145,11 +161,74 @@
 	git ls-files --error-unmatch dense_entry
 '
 
+test_expect_success 'git add fails outside of sparse-checkout definition' '
+	test_when_finished git sparse-checkout disable &&
+	test_commit a &&
+	git sparse-checkout init &&
+	git sparse-checkout set a &&
+	echo >>sparse_entry &&
+
+	git update-index --no-skip-worktree sparse_entry &&
+	test_must_fail git add sparse_entry &&
+	test_sparse_entry_unstaged &&
+
+	test_must_fail git add --chmod=+x sparse_entry &&
+	test_sparse_entry_unstaged &&
+
+	test_must_fail git add --renormalize sparse_entry &&
+	test_sparse_entry_unstaged &&
+
+	# Avoid munging CRLFs to avoid an error message
+	git -c core.autocrlf=input add --sparse sparse_entry 2>stderr &&
+	test_must_be_empty stderr &&
+	test-tool read-cache --table >actual &&
+	grep "^100644 blob.*sparse_entry\$" actual &&
+
+	git add --sparse --chmod=+x sparse_entry 2>stderr &&
+	test_must_be_empty stderr &&
+	test-tool read-cache --table >actual &&
+	grep "^100755 blob.*sparse_entry\$" actual &&
+
+	git reset &&
+
+	# This will print a message over stderr on Windows.
+	git add --sparse --renormalize sparse_entry &&
+	git status --porcelain >actual &&
+	grep "^M  sparse_entry\$" actual
+'
+
 test_expect_success 'add obeys advice.updateSparsePath' '
 	setup_sparse_entry &&
 	test_must_fail git -c advice.updateSparsePath=false add sparse_entry 2>stderr &&
+	test_sparse_entry_unstaged &&
 	test_cmp sparse_entry_error stderr
 
 '
 
+test_expect_success 'add allows sparse entries with --sparse' '
+	git sparse-checkout set a &&
+	echo modified >sparse_entry &&
+	test_must_fail git add sparse_entry &&
+	test_sparse_entry_unchanged &&
+	git add --sparse sparse_entry 2>stderr &&
+	test_must_be_empty stderr
+'
+
+test_expect_success 'can add files from non-sparse dir' '
+	git sparse-checkout set w !/x y/ &&
+	mkdir -p w x/y &&
+	touch w/f x/y/f &&
+	git add w/f x/y/f 2>stderr &&
+	test_must_be_empty stderr
+'
+
+test_expect_success 'refuse to add non-skip-worktree file from sparse dir' '
+	git sparse-checkout set !/x y/ !x/y/z &&
+	mkdir -p x/y/z &&
+	touch x/y/z/f &&
+	test_must_fail git add x/y/z/f 2>stderr &&
+	echo x/y/z/f | cat sparse_error_header - sparse_hint >expect &&
+	test_cmp expect stderr
+'
+
 test_done
diff --git a/t/t3902-quoted.sh b/t/t3902-quoted.sh
index f528008..72a5a56 100755
--- a/t/t3902-quoted.sh
+++ b/t/t3902-quoted.sh
@@ -5,6 +5,7 @@
 
 test_description='quoted output'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 FN='濱野'
diff --git a/t/t3905-stash-include-untracked.sh b/t/t3905-stash-include-untracked.sh
index dd2cdcc..5390eec 100755
--- a/t/t3905-stash-include-untracked.sh
+++ b/t/t3905-stash-include-untracked.sh
@@ -422,4 +422,10 @@
 	test_must_be_empty actual
 '
 
+test_expect_success 'stash -u ignores sub-repository' '
+	test_when_finished "rm -rf sub-repo" &&
+	git init sub-repo &&
+	git stash -u
+'
+
 test_done
diff --git a/t/t4002-diff-basic.sh b/t/t4002-diff-basic.sh
index 6a9f010..ea52e5b 100755
--- a/t/t4002-diff-basic.sh
+++ b/t/t4002-diff-basic.sh
@@ -6,6 +6,8 @@
 test_description='Test diff raw-output.
 
 '
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 . "$TEST_DIRECTORY"/lib-read-tree-m-3way.sh
diff --git a/t/t4003-diff-rename-1.sh b/t/t4003-diff-rename-1.sh
index db07ff3..f4485a8 100755
--- a/t/t4003-diff-rename-1.sh
+++ b/t/t4003-diff-rename-1.sh
@@ -11,7 +11,7 @@
 
 test_expect_success \
     'prepare reference tree' \
-    'cat "$TEST_DIRECTORY"/lib-diff/COPYING >COPYING &&
+    'COPYING_test_data >COPYING &&
      echo frotz >rezrov &&
     git update-index --add COPYING rezrov &&
     tree=$(git write-tree) &&
@@ -99,7 +99,7 @@
 
 test_expect_success \
     'prepare work tree once again' \
-    'cat "$TEST_DIRECTORY"/lib-diff/COPYING >COPYING &&
+    'COPYING_test_data >COPYING &&
      git update-index --add --remove COPYING COPYING.1'
 
 # tree has COPYING and rezrov.  work tree has COPYING and COPYING.1,
diff --git a/t/t4005-diff-rename-2.sh b/t/t4005-diff-rename-2.sh
index 8647906..6f1b323 100755
--- a/t/t4005-diff-rename-2.sh
+++ b/t/t4005-diff-rename-2.sh
@@ -9,7 +9,7 @@
 . "$TEST_DIRECTORY"/lib-diff.sh ;# test-lib chdir's into trash
 
 test_expect_success 'setup reference tree' '
-	cat "$TEST_DIRECTORY"/lib-diff/COPYING >COPYING &&
+	COPYING_test_data >COPYING &&
 	echo frotz >rezrov &&
 	git update-index --add COPYING rezrov &&
 	tree=$(git write-tree) &&
@@ -64,7 +64,7 @@
 # nows how to say Copy.
 
 test_expect_success 'validate output from rename/copy detection (#3)' '
-	cat "$TEST_DIRECTORY"/lib-diff/COPYING >COPYING &&
+	COPYING_test_data >COPYING &&
 	git update-index --add --remove COPYING COPYING.1 &&
 
 	cat <<-EOF >expected &&
diff --git a/t/t4007-rename-3.sh b/t/t4007-rename-3.sh
index cbb9c62..c634653 100755
--- a/t/t4007-rename-3.sh
+++ b/t/t4007-rename-3.sh
@@ -11,13 +11,12 @@
 
 test_expect_success 'prepare reference tree' '
 	mkdir path0 path1 &&
-	cp "$TEST_DIRECTORY"/lib-diff/COPYING path0/COPYING &&
+	COPYING_test_data >path0/COPYING &&
 	git update-index --add path0/COPYING &&
 	tree=$(git write-tree) &&
-	echo $tree
+	blob=$(git rev-parse :path0/COPYING)
 '
 
-blob=$(git hash-object "$TEST_DIRECTORY/lib-diff/COPYING")
 test_expect_success 'prepare work tree' '
 	cp path0/COPYING path1/COPYING &&
 	git update-index --add --remove path0/COPYING path1/COPYING
diff --git a/t/t4008-diff-break-rewrite.sh b/t/t4008-diff-break-rewrite.sh
index 2299f27..562aaf3 100755
--- a/t/t4008-diff-break-rewrite.sh
+++ b/t/t4008-diff-break-rewrite.sh
@@ -25,8 +25,8 @@
 . "$TEST_DIRECTORY"/lib-diff.sh ;# test-lib chdir's into trash
 
 test_expect_success setup '
-	cat "$TEST_DIRECTORY"/lib-diff/README >file0 &&
-	cat "$TEST_DIRECTORY"/lib-diff/COPYING >file1 &&
+	echo some dissimilar content >file0 &&
+	COPYING_test_data >file1 &&
 	blob0_id=$(git hash-object file0) &&
 	blob1_id=$(git hash-object file1) &&
 	git update-index --add file0 file1 &&
diff --git a/t/t4009-diff-rename-4.sh b/t/t4009-diff-rename-4.sh
index b1da807..59b7f44 100755
--- a/t/t4009-diff-rename-4.sh
+++ b/t/t4009-diff-rename-4.sh
@@ -11,7 +11,7 @@
 
 test_expect_success \
     'prepare reference tree' \
-    'cat "$TEST_DIRECTORY"/lib-diff/COPYING >COPYING &&
+    'COPYING_test_data >COPYING &&
      echo frotz >rezrov &&
     git update-index --add COPYING rezrov &&
     orig=$(git hash-object COPYING) &&
@@ -81,7 +81,7 @@
 
 test_expect_success \
     'prepare work tree once again' \
-    'cat "$TEST_DIRECTORY"/lib-diff/COPYING >COPYING &&
+    'COPYING_test_data >COPYING &&
      git update-index --add --remove COPYING COPYING.1'
 
 git diff-index -z -C --find-copies-harder $tree >current
diff --git a/t/t4016-diff-quote.sh b/t/t4016-diff-quote.sh
index 876271d..5a8d887 100755
--- a/t/t4016-diff-quote.sh
+++ b/t/t4016-diff-quote.sh
@@ -6,6 +6,7 @@
 test_description='Quoting paths in diff output.
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 P0='pathname'
diff --git a/t/t4018/java-class-member-function b/t/t4018/java-class-member-function
index 298bc7a..3b95f68 100644
--- a/t/t4018/java-class-member-function
+++ b/t/t4018/java-class-member-function
@@ -3,6 +3,10 @@
 	int special;
 	public static void main(String RIGHT[])
 	{
+		someMethodCall();
+		someOtherMethod("17")
+			.doThat();
+		// Whatever
 		System.out.print("ChangeMe");
 	}
 }
diff --git a/t/t4018/java-enum-constant b/t/t4018/java-enum-constant
new file mode 100644
index 0000000..a1931c8
--- /dev/null
+++ b/t/t4018/java-enum-constant
@@ -0,0 +1,6 @@
+private enum RIGHT {
+    ONE,
+    TWO,
+    THREE,
+    ChangeMe
+}
diff --git a/t/t4018/java-method-return-generic-bounded b/t/t4018/java-method-return-generic-bounded
new file mode 100644
index 0000000..66dd78c
--- /dev/null
+++ b/t/t4018/java-method-return-generic-bounded
@@ -0,0 +1,9 @@
+class MyExample {
+    public <T extends Bar & Foo<T>, R> Map<T, R[]> foo(String[] RIGHT) {
+        someMethodCall();
+        someOtherMethod()
+            .doThat();
+        // Whatever...
+        return (List<T>) Arrays.asList("ChangeMe");
+    }
+}
diff --git a/t/t4018/java-method-return-generic-wildcard b/t/t4018/java-method-return-generic-wildcard
new file mode 100644
index 0000000..96e9e5f
--- /dev/null
+++ b/t/t4018/java-method-return-generic-wildcard
@@ -0,0 +1,9 @@
+class MyExample {
+    public List<? extends Comparable> foo(String[] RIGHT) {
+        someMethodCall();
+        someOtherMethod()
+            .doThat();
+        // Whatever...
+        return Arrays.asList("ChangeMe");
+    }
+}
diff --git a/t/t4018/java-nested-field b/t/t4018/java-nested-field
new file mode 100644
index 0000000..d92d3ec
--- /dev/null
+++ b/t/t4018/java-nested-field
@@ -0,0 +1,6 @@
+class MyExample {
+    private static class RIGHT {
+        // change an inner class field
+        String inner = "ChangeMe";
+    }
+}
diff --git a/t/t4018/php-enum b/t/t4018/php-enum
new file mode 100644
index 0000000..91a69c1
--- /dev/null
+++ b/t/t4018/php-enum
@@ -0,0 +1,4 @@
+enum RIGHT: string
+{
+    case Foo = 'ChangeMe';
+}
diff --git a/t/t4019-diff-wserror.sh b/t/t4019-diff-wserror.sh
index c6135c7..c68729a 100755
--- a/t/t4019-diff-wserror.sh
+++ b/t/t4019-diff-wserror.sh
@@ -2,6 +2,7 @@
 
 test_description='diff whitespace error detection'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t4022-diff-rewrite.sh b/t/t4022-diff-rewrite.sh
index 6d1c3d9..1c89050 100755
--- a/t/t4022-diff-rewrite.sh
+++ b/t/t4022-diff-rewrite.sh
@@ -3,15 +3,17 @@
 test_description='rewrite diff'
 
 . ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-diff-data.sh
 
 test_expect_success setup '
 
-	cat "$TEST_DIRECTORY"/../COPYING >test &&
+	COPYING_test_data >test.data &&
+	cp test.data test &&
 	git add test &&
 	tr \
 	  "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ" \
 	  "nopqrstuvwxyzabcdefghijklmNOPQRSTUVWXYZABCDEFGHIJKLM" \
-	  <"$TEST_DIRECTORY"/../COPYING >test &&
+	  <test.data >test &&
 	echo "to be deleted" >test2 &&
 	blob=$(git hash-object test2) &&
 	blob=$(git rev-parse --short $blob) &&
diff --git a/t/t4023-diff-rename-typechange.sh b/t/t4023-diff-rename-typechange.sh
index 8c98237..47d6f35 100755
--- a/t/t4023-diff-rename-typechange.sh
+++ b/t/t4023-diff-rename-typechange.sh
@@ -3,25 +3,26 @@
 test_description='typechange rename detection'
 
 . ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-diff.sh
 
 test_expect_success setup '
 
 	rm -f foo bar &&
-	cat "$TEST_DIRECTORY"/../COPYING >foo &&
+	COPYING_test_data >foo &&
 	test_ln_s_add linklink bar &&
 	git add foo &&
 	git commit -a -m Initial &&
 	git tag one &&
 
 	git rm -f foo bar &&
-	cat "$TEST_DIRECTORY"/../COPYING >bar &&
+	COPYING_test_data >bar &&
 	test_ln_s_add linklink foo &&
 	git add bar &&
 	git commit -a -m Second &&
 	git tag two &&
 
 	git rm -f foo bar &&
-	cat "$TEST_DIRECTORY"/../COPYING >foo &&
+	COPYING_test_data >foo &&
 	git add foo &&
 	git commit -a -m Third &&
 	git tag three &&
@@ -35,7 +36,7 @@
 	# This is purely for sanity check
 
 	git rm -f foo bar &&
-	cat "$TEST_DIRECTORY"/../COPYING >foo &&
+	COPYING_test_data >foo &&
 	cat "$TEST_DIRECTORY"/../Makefile >bar &&
 	git add foo bar &&
 	git commit -a -m Fifth &&
@@ -43,7 +44,7 @@
 
 	git rm -f foo bar &&
 	cat "$TEST_DIRECTORY"/../Makefile >foo &&
-	cat "$TEST_DIRECTORY"/../COPYING >bar &&
+	COPYING_test_data >bar &&
 	git add foo bar &&
 	git commit -a -m Sixth &&
 	git tag six
diff --git a/t/t4025-hunk-header.sh b/t/t4025-hunk-header.sh
index 35578f2..6356961 100755
--- a/t/t4025-hunk-header.sh
+++ b/t/t4025-hunk-header.sh
@@ -2,6 +2,7 @@
 
 test_description='diff hunk header truncation'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 N='日本語'
diff --git a/t/t4026-color.sh b/t/t4026-color.sh
index c0b642c..cc73161 100755
--- a/t/t4026-color.sh
+++ b/t/t4026-color.sh
@@ -4,6 +4,8 @@
 #
 
 test_description='Test diff/status color escape codes'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 ESC=$(printf '\033')
diff --git a/t/t4034/cpp/expect b/t/t4034/cpp/expect
index 37d1ea2..dc500ae 100644
--- a/t/t4034/cpp/expect
+++ b/t/t4034/cpp/expect
@@ -1,36 +1,35 @@
 <BOLD>diff --git a/pre b/post<RESET>
-<BOLD>index 23d5c8a..7e8c026 100644<RESET>
+<BOLD>index a1a09b7..f1b6f3c 100644<RESET>
 <BOLD>--- a/pre<RESET>
 <BOLD>+++ b/post<RESET>
-<CYAN>@@ -1,19 +1,19 @@<RESET>
-Foo() : x(0<RED>&&1<RESET><GREEN>&42<RESET>) { <GREEN>bar(x);<RESET> }
+<CYAN>@@ -1,30 +1,30 @@<RESET>
+Foo() : x(0<RED>&&1<RESET><GREEN>&42<RESET>) { <RED>foo0<RESET><GREEN>bar<RESET>(x.<RED>find<RESET><GREEN>Find<RESET>); }
 cout<<"Hello World<RED>!<RESET><GREEN>?<RESET>\n"<<endl;
-<GREEN>(<RESET>1<GREEN>) (<RESET>-1e10<GREEN>) (<RESET>0xabcdef<GREEN>)<RESET> '<RED>x<RESET><GREEN>y<RESET>'
-[<RED>a<RESET><GREEN>x<RESET>] <RED>a<RESET><GREEN>x<RESET>-><RED>b a<RESET><GREEN>y x<RESET>.<RED>b<RESET><GREEN>y<RESET>
-!<RED>a<RESET><GREEN>x<RESET> ~<RED>a a<RESET><GREEN>x x<RESET>++ <RED>a<RESET><GREEN>x<RESET>-- <RED>a<RESET><GREEN>x<RESET>*<RED>b a<RESET><GREEN>y x<RESET>&<RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET>*<RED>b a<RESET><GREEN>y x<RESET>/<RED>b a<RESET><GREEN>y x<RESET>%<RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET>+<RED>b a<RESET><GREEN>y x<RESET>-<RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET><<<RED>b a<RESET><GREEN>y x<RESET>>><RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET><<RED>b a<RESET><GREEN>y x<RESET><=<RED>b a<RESET><GREEN>y x<RESET>><RED>b a<RESET><GREEN>y x<RESET>>=<RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET>==<RED>b a<RESET><GREEN>y x<RESET>!=<RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET>&<RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET>^<RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET>|<RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET>&&<RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET>||<RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET>?<RED>b<RESET><GREEN>y<RESET>:z
-<RED>a<RESET><GREEN>x<RESET>=<RED>b a<RESET><GREEN>y x<RESET>+=<RED>b a<RESET><GREEN>y x<RESET>-=<RED>b a<RESET><GREEN>y x<RESET>*=<RED>b a<RESET><GREEN>y x<RESET>/=<RED>b a<RESET><GREEN>y x<RESET>%=<RED>b a<RESET><GREEN>y x<RESET><<=<RED>b a<RESET><GREEN>y x<RESET>>>=<RED>b a<RESET><GREEN>y x<RESET>&=<RED>b a<RESET><GREEN>y x<RESET>^=<RED>b a<RESET><GREEN>y x<RESET>|=<RED>b<RESET>
-<RED>a<RESET><GREEN>y<RESET>
-<GREEN>x<RESET>,y
-<RED>a<RESET><GREEN>x<RESET>::<RED>b<RESET><GREEN>y<RESET>
+<GREEN>(<RESET>1 <RED>-<RESET><GREEN>+<RESET>1e10 0xabcdef<GREEN>)<RESET> '<RED>x<RESET><GREEN>2<RESET>'
+// long double<RESET>
+<RED>3.141592653e-10l<RESET><GREEN>3.141592654e+10l<RESET>
+// float<RESET>
+<RED>120E5f<RESET><GREEN>120E6f<RESET>
+// hex<RESET>
+<RED>0xdead<RESET><GREEN>0xdeaf<RESET>'1<RED>eaF<RESET><GREEN>eaf<RESET>+<RED>8ULL<RESET><GREEN>7ULL<RESET>
+// octal<RESET>
+<RED>01234567<RESET><GREEN>01234560<RESET>
+// binary<RESET>
+<RED>0b1000<RESET><GREEN>0b1100<RESET>+e1
+// expression<RESET>
+1.5-e+<RED>2<RESET><GREEN>3<RESET>+f
+// another one<RESET>
+str.e+<RED>65<RESET><GREEN>75<RESET>
+[a] b<RED>-><RESET><GREEN>->*<RESET>v d<RED>.<RESET><GREEN>.*<RESET>e
+<GREEN>~<RESET>!a <GREEN>!<RESET>~b c<RED>++<RESET><GREEN>+<RESET> d<RED>--<RESET><GREEN>-<RESET> e*<GREEN>*<RESET>f g<RED>&<RESET><GREEN>&&<RESET>h
+a<RED>*<RESET><GREEN>*=<RESET>b c<RED>/<RESET><GREEN>/=<RESET>d e<RED>%<RESET><GREEN>%=<RESET>f
+a<RED>+<RESET><GREEN>++<RESET>b c<RED>-<RESET><GREEN>--<RESET>d
+a<RED><<<RESET><GREEN><<=<RESET>b c<RED>>><RESET><GREEN>>>=<RESET>d
+a<RED><<RESET><GREEN><=<RESET>b c<RED><=<RESET><GREEN><<RESET>d e<RED>><RESET><GREEN>>=<RESET>f g<RED>>=<RESET><GREEN>><RESET>h i<RED><=<RESET><GREEN><=><RESET>j
+a<RED>==<RESET><GREEN>!=<RESET>b c<RED>!=<RESET><GREEN>=<RESET>d
+a<RED>^<RESET><GREEN>^=<RESET>b c<RED>|<RESET><GREEN>|=<RESET>d e<RED>&&<RESET><GREEN>&=<RESET>f
+a<RED>||<RESET><GREEN>|<RESET>b
+a?<GREEN>:<RESET>b
+a<RED>=<RESET><GREEN>==<RESET>b c<RED>+=<RESET><GREEN>+<RESET>d e<RED>-=<RESET><GREEN>-<RESET>f g<RED>*=<RESET><GREEN>*<RESET>h i<RED>/=<RESET><GREEN>/<RESET>j k<RED>%=<RESET><GREEN>%<RESET>l m<RED><<=<RESET><GREEN><<<RESET>n o<RED>>>=<RESET><GREEN>>><RESET>p q<RED>&=<RESET><GREEN>&<RESET>r s<RED>^=<RESET><GREEN>^<RESET>t u<RED>|=<RESET><GREEN>|<RESET>v
+a,b<RESET>
+a<RED>::<RESET><GREEN>:<RESET>b
diff --git a/t/t4034/cpp/post b/t/t4034/cpp/post
index 7e8c026..f1b6f3c 100644
--- a/t/t4034/cpp/post
+++ b/t/t4034/cpp/post
@@ -1,19 +1,30 @@
-Foo() : x(0&42) { bar(x); }
+Foo() : x(0&42) { bar(x.Find); }
 cout<<"Hello World?\n"<<endl;
-(1) (-1e10) (0xabcdef) 'y'
-[x] x->y x.y
-!x ~x x++ x-- x*y x&y
-x*y x/y x%y
-x+y x-y
-x<<y x>>y
-x<y x<=y x>y x>=y
-x==y x!=y
-x&y
-x^y
-x|y
-x&&y
-x||y
-x?y:z
-x=y x+=y x-=y x*=y x/=y x%=y x<<=y x>>=y x&=y x^=y x|=y
-x,y
-x::y
+(1 +1e10 0xabcdef) '2'
+// long double
+3.141592654e+10l
+// float
+120E6f
+// hex
+0xdeaf'1eaf+7ULL
+// octal
+01234560
+// binary
+0b1100+e1
+// expression
+1.5-e+3+f
+// another one
+str.e+75
+[a] b->*v d.*e
+~!a !~b c+ d- e**f g&&h
+a*=b c/=d e%=f
+a++b c--d
+a<<=b c>>=d
+a<=b c<d e>=f g>h i<=>j
+a!=b c=d
+a^=b c|=d e&=f
+a|b
+a?:b
+a==b c+d e-f g*h i/j k%l m<<n o>>p q&r s^t u|v
+a,b
+a:b
diff --git a/t/t4034/cpp/pre b/t/t4034/cpp/pre
index 23d5c8a..a1a09b7 100644
--- a/t/t4034/cpp/pre
+++ b/t/t4034/cpp/pre
@@ -1,19 +1,30 @@
-Foo():x(0&&1){}
+Foo():x(0&&1){ foo0( x.find); }
 cout<<"Hello World!\n"<<endl;
 1 -1e10 0xabcdef 'x'
-[a] a->b a.b
-!a ~a a++ a-- a*b a&b
-a*b a/b a%b
-a+b a-b
-a<<b a>>b
-a<b a<=b a>b a>=b
-a==b a!=b
-a&b
-a^b
-a|b
-a&&b
+// long double
+3.141592653e-10l
+// float
+120E5f
+// hex
+0xdead'1eaF+8ULL
+// octal
+01234567
+// binary
+0b1000+e1
+// expression
+1.5-e+2+f
+// another one
+str.e+65
+[a] b->v d.e
+!a ~b c++ d-- e*f g&h
+a*b c/d e%f
+a+b c-d
+a<<b c>>d
+a<b c<=d e>f g>=h i<=j
+a==b c!=d
+a^b c|d e&&f
 a||b
-a?b:z
-a=b a+=b a-=b a*=b a/=b a%=b a<<=b a>>=b a&=b a^=b a|=b
-a,y
+a?b
+a=b c+=d e-=f g*=h i/=j k%=l m<<=n o>>=p q&=r s^=t u|=v
+a,b
 a::b
diff --git a/t/t4060-diff-submodule-option-diff-format.sh b/t/t4060-diff-submodule-option-diff-format.sh
index dc7b242..d86e38a 100755
--- a/t/t4060-diff-submodule-option-diff-format.sh
+++ b/t/t4060-diff-submodule-option-diff-format.sh
@@ -361,7 +361,6 @@
 rm -f sm1 &&
 test_create_repo sm1 &&
 head6=$(add_file sm1 foo6 foo7)
-fullhead6=$(cd sm1; git rev-parse --verify HEAD)
 test_expect_success 'nonexistent commit' '
 	git diff-index -p --submodule=diff HEAD >actual &&
 	cat >expected <<-EOF &&
@@ -704,10 +703,26 @@
 	diff_cmp expected actual
 '
 
-commit_file sm2
+cat >.gitmodules <<-EOF
+[submodule "sm2"]
+	path = sm2
+	url = bogus_url
+EOF
+git add .gitmodules
+commit_file sm2 .gitmodules
+
 test_expect_success 'given commit' '
 	git diff-index -p --submodule=diff HEAD^ >actual &&
 	cat >expected <<-EOF &&
+	diff --git a/.gitmodules b/.gitmodules
+	new file mode 100644
+	index 1234567..89abcde
+	--- /dev/null
+	+++ b/.gitmodules
+	@@ -0,0 +1,3 @@
+	+[submodule "sm2"]
+	+path = sm2
+	+url = bogus_url
 	Submodule sm1 $head7...0000000 (submodule deleted)
 	Submodule sm2 0000000...$head9 (new submodule)
 	diff --git a/sm2/foo8 b/sm2/foo8
@@ -729,15 +744,21 @@
 '
 
 test_expect_success 'setup .git file for sm2' '
-	(cd sm2 &&
-	 REAL="$(pwd)/../.real" &&
-	 mv .git "$REAL" &&
-	 echo "gitdir: $REAL" >.git)
+	git submodule absorbgitdirs sm2
 '
 
 test_expect_success 'diff --submodule=diff with .git file' '
 	git diff --submodule=diff HEAD^ >actual &&
 	cat >expected <<-EOF &&
+	diff --git a/.gitmodules b/.gitmodules
+	new file mode 100644
+	index 1234567..89abcde
+	--- /dev/null
+	+++ b/.gitmodules
+	@@ -0,0 +1,3 @@
+	+[submodule "sm2"]
+	+path = sm2
+	+url = bogus_url
 	Submodule sm1 $head7...0000000 (submodule deleted)
 	Submodule sm2 0000000...$head9 (new submodule)
 	diff --git a/sm2/foo8 b/sm2/foo8
@@ -758,9 +779,67 @@
 	diff_cmp expected actual
 '
 
+mv sm2 sm2-bak
+
+test_expect_success 'deleted submodule with .git file' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $head7...0000000 (submodule deleted)
+	Submodule sm2 $head9...0000000 (submodule deleted)
+	diff --git a/sm2/foo8 b/sm2/foo8
+	deleted file mode 100644
+	index 1234567..89abcde
+	--- a/sm2/foo8
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo8
+	diff --git a/sm2/foo9 b/sm2/foo9
+	deleted file mode 100644
+	index 1234567..89abcde
+	--- a/sm2/foo9
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo9
+	EOF
+	diff_cmp expected actual
+'
+
+echo submodule-to-blob>sm2
+
+test_expect_success 'typechanged(submodule->blob) submodule with .git file' '
+	git diff-index -p --submodule=diff HEAD >actual &&
+	cat >expected <<-EOF &&
+	Submodule sm1 $head7...0000000 (submodule deleted)
+	Submodule sm2 $head9...0000000 (submodule deleted)
+	diff --git a/sm2/foo8 b/sm2/foo8
+	deleted file mode 100644
+	index 1234567..89abcde
+	--- a/sm2/foo8
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo8
+	diff --git a/sm2/foo9 b/sm2/foo9
+	deleted file mode 100644
+	index 1234567..89abcde
+	--- a/sm2/foo9
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo9
+	diff --git a/sm2 b/sm2
+	new file mode 100644
+	index 1234567..89abcde
+	--- /dev/null
+	+++ b/sm2
+	@@ -0,0 +1 @@
+	+submodule-to-blob
+	EOF
+	diff_cmp expected actual
+'
+
+rm sm2
+mv sm2-bak sm2
+
 test_expect_success 'setup nested submodule' '
-	git submodule add -f ./sm2 &&
-	git commit -a -m "add sm2" &&
 	git -C sm2 submodule add ../sm2 nested &&
 	git -C sm2 commit -a -m "nested sub" &&
 	head10=$(git -C sm2 rev-parse --short --verify HEAD)
@@ -791,6 +870,7 @@
 
 test_expect_success 'diff --submodule=diff recurses into nested submodules' '
 	cat >expected <<-EOF &&
+	Submodule sm1 $head7...0000000 (submodule deleted)
 	Submodule sm2 contains modified content
 	Submodule sm2 $head9..$head10:
 	diff --git a/sm2/.gitmodules b/sm2/.gitmodules
@@ -830,4 +910,67 @@
 	diff_cmp expected actual
 '
 
+(cd sm2; commit_file nested)
+commit_file sm2
+head12=$(cd sm2; git rev-parse --short --verify HEAD)
+
+mv sm2 sm2-bak
+
+test_expect_success 'diff --submodule=diff recurses into deleted nested submodules' '
+	cat >expected <<-EOF &&
+	Submodule sm1 $head7...0000000 (submodule deleted)
+	Submodule sm2 $head12...0000000 (submodule deleted)
+	diff --git a/sm2/.gitmodules b/sm2/.gitmodules
+	deleted file mode 100644
+	index 3a816b8..0000000
+	--- a/sm2/.gitmodules
+	+++ /dev/null
+	@@ -1,3 +0,0 @@
+	-[submodule "nested"]
+	-	path = nested
+	-	url = ../sm2
+	diff --git a/sm2/foo8 b/sm2/foo8
+	deleted file mode 100644
+	index db9916b..0000000
+	--- a/sm2/foo8
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo8
+	diff --git a/sm2/foo9 b/sm2/foo9
+	deleted file mode 100644
+	index 9c3b4f6..0000000
+	--- a/sm2/foo9
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo9
+	Submodule nested $head11...0000000 (submodule deleted)
+	diff --git a/sm2/nested/file b/sm2/nested/file
+	deleted file mode 100644
+	index ca281f5..0000000
+	--- a/sm2/nested/file
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-nested content
+	diff --git a/sm2/nested/foo8 b/sm2/nested/foo8
+	deleted file mode 100644
+	index db9916b..0000000
+	--- a/sm2/nested/foo8
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo8
+	diff --git a/sm2/nested/foo9 b/sm2/nested/foo9
+	deleted file mode 100644
+	index 9c3b4f6..0000000
+	--- a/sm2/nested/foo9
+	+++ /dev/null
+	@@ -1 +0,0 @@
+	-foo9
+	EOF
+	git diff --submodule=diff >actual 2>err &&
+	test_must_be_empty err &&
+	diff_cmp expected actual
+'
+
+mv sm2-bak sm2
+
 test_done
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index 9dfead9..6a650da 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -1616,6 +1616,16 @@
 	git commit -S -m signed_commit
 '
 
+test_expect_success GPGSSH 'setup sshkey signed branch' '
+	test_config gpg.format ssh &&
+	test_config user.signingkey "${GPGSSH_KEY_PRIMARY}" &&
+	test_when_finished "git reset --hard && git checkout main" &&
+	git checkout -b signed-ssh main &&
+	echo foo >foo &&
+	git add foo &&
+	git commit -S -m signed_commit
+'
+
 test_expect_success GPGSM 'log x509 fingerprint' '
 	echo "F8BF62E0693D0694816377099909C779FA23FD65 | " >expect &&
 	git log -n1 --format="%GF | %GP" signed-x509 >actual &&
@@ -1628,6 +1638,13 @@
 	test_cmp expect actual
 '
 
+test_expect_success GPGSSH 'log ssh key fingerprint' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	ssh-keygen -lf  "${GPGSSH_KEY_PRIMARY}" | awk "{print \$2\" | \"}" >expect &&
+	git log -n1 --format="%GF | %GP" signed-ssh >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success GPG 'log --graph --show-signature' '
 	git log --graph --show-signature -n1 signed >actual &&
 	grep "^| gpg: Signature made" actual &&
@@ -1640,6 +1657,12 @@
 	grep "^| gpgsm: Good signature" actual
 '
 
+test_expect_success GPGSSH 'log --graph --show-signature ssh' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git log --graph --show-signature -n1 signed-ssh >actual &&
+	grep "${GOOD_SIGNATURE_TRUSTED}" actual
+'
+
 test_expect_success GPG 'log --graph --show-signature for merged tag' '
 	test_when_finished "git reset --hard && git checkout main" &&
 	git checkout -b plain main &&
diff --git a/t/t4210-log-i18n.sh b/t/t4210-log-i18n.sh
index 0141f36..d2dfcf1 100755
--- a/t/t4210-log-i18n.sh
+++ b/t/t4210-log-i18n.sh
@@ -131,11 +131,4 @@
 	fi
 done
 
-test_expect_success 'log shows warning when conversion fails' '
-	enc=this-encoding-does-not-exist &&
-	git log -1 --encoding=$enc 2>err &&
-	echo "warning: unable to reencode commit to ${SQ}${enc}${SQ}" >expect &&
-	test_cmp expect err
-'
-
 test_done
diff --git a/t/t4300-merge-tree.sh b/t/t4300-merge-tree.sh
index e59601e..c52c8a2 100755
--- a/t/t4300-merge-tree.sh
+++ b/t/t4300-merge-tree.sh
@@ -4,6 +4,8 @@
 #
 
 test_description='git merge-tree'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t5304-prune.sh b/t/t5304-prune.sh
index 7cabb85..8ae314a 100755
--- a/t/t5304-prune.sh
+++ b/t/t5304-prune.sh
@@ -291,6 +291,7 @@
 		cat ../expected >blob &&
 		git add blob &&
 		git commit -m "second commit in third" &&
+		git clean -f && # Remove untracked left behind by deleting index
 		git reset --hard HEAD^
 	) &&
 	git prune --expire=now &&
diff --git a/t/t5310-pack-bitmaps.sh b/t/t5310-pack-bitmaps.sh
index b028387..673baa5 100755
--- a/t/t5310-pack-bitmaps.sh
+++ b/t/t5310-pack-bitmaps.sh
@@ -8,6 +8,10 @@
 . "$TEST_DIRECTORY"/lib-bundle.sh
 . "$TEST_DIRECTORY"/lib-bitmap.sh
 
+# t5310 deals only with single-pack bitmaps, so don't write MIDX bitmaps in
+# their place.
+GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0
+
 objpath () {
 	echo ".git/objects/$(echo "$1" | sed -e 's|\(..\)|\1/|')"
 }
@@ -25,93 +29,10 @@
 	grep -Ff "$1" "$2"
 }
 
-# To ensure the logic for "maximal commits" is exercised, make
-# the repository a bit more complicated.
-#
-#    other                         second
-#      *                             *
-# (99 commits)                  (99 commits)
-#      *                             *
-#      |\                           /|
-#      | * octo-other  octo-second * |
-#      |/|\_________  ____________/|\|
-#      | \          \/  __________/  |
-#      |  | ________/\ /             |
-#      *  |/          * merge-right  *
-#      | _|__________/ \____________ |
-#      |/ |                         \|
-# (l1) *  * merge-left               * (r1)
-#      | / \________________________ |
-#      |/                           \|
-# (l2) *                             * (r2)
-#       \___________________________ |
-#                                   \|
-#                                    * (base)
-#
-# We only push bits down the first-parent history, which
-# makes some of these commits unimportant!
-#
-# The important part for the maximal commit algorithm is how
-# the bitmasks are extended. Assuming starting bit positions
-# for second (bit 0) and other (bit 1), the bitmasks at the
-# end should be:
-#
-#      second: 1       (maximal, selected)
-#       other: 01      (maximal, selected)
-#      (base): 11 (maximal)
-#
-# This complicated history was important for a previous
-# version of the walk that guarantees never walking a
-# commit multiple times. That goal might be important
-# again, so preserve this complicated case. For now, this
-# test will guarantee that the bitmaps are computed
-# correctly, even with the repeat calculations.
+setup_bitmap_history
 
-test_expect_success 'setup repo with moderate-sized history' '
-	test_commit_bulk --id=file 10 &&
-	git branch -M second &&
-	git checkout -b other HEAD~5 &&
-	test_commit_bulk --id=side 10 &&
-
-	# add complicated history setup, including merges and
-	# ambiguous merge-bases
-
-	git checkout -b merge-left other~2 &&
-	git merge second~2 -m "merge-left" &&
-
-	git checkout -b merge-right second~1 &&
-	git merge other~1 -m "merge-right" &&
-
-	git checkout -b octo-second second &&
-	git merge merge-left merge-right -m "octopus-second" &&
-
-	git checkout -b octo-other other &&
-	git merge merge-left merge-right -m "octopus-other" &&
-
-	git checkout other &&
-	git merge octo-other -m "pull octopus" &&
-
-	git checkout second &&
-	git merge octo-second -m "pull octopus" &&
-
-	# Remove these branches so they are not selected
-	# as bitmap tips
-	git branch -D merge-left &&
-	git branch -D merge-right &&
-	git branch -D octo-other &&
-	git branch -D octo-second &&
-
-	# add padding to make these merges less interesting
-	# and avoid having them selected for bitmaps
-	test_commit_bulk --id=file 100 &&
-	git checkout other &&
-	test_commit_bulk --id=side 100 &&
-	git checkout second &&
-
-	bitmaptip=$(git rev-parse second) &&
-	blob=$(echo tagged-blob | git hash-object -w --stdin) &&
-	git tag tagged-blob $blob &&
-	git config repack.writebitmaps true
+test_expect_success 'setup writing bitmaps during repack' '
+	git config repack.writeBitmaps true
 '
 
 test_expect_success 'full repack creates bitmaps' '
@@ -123,109 +44,7 @@
 	grep "\"key\":\"num_maximal_commits\",\"value\":\"107\"" trace
 '
 
-test_expect_success 'rev-list --test-bitmap verifies bitmaps' '
-	git rev-list --test-bitmap HEAD
-'
-
-rev_list_tests_head () {
-	test_expect_success "counting commits via bitmap ($state, $branch)" '
-		git rev-list --count $branch >expect &&
-		git rev-list --use-bitmap-index --count $branch >actual &&
-		test_cmp expect actual
-	'
-
-	test_expect_success "counting partial commits via bitmap ($state, $branch)" '
-		git rev-list --count $branch~5..$branch >expect &&
-		git rev-list --use-bitmap-index --count $branch~5..$branch >actual &&
-		test_cmp expect actual
-	'
-
-	test_expect_success "counting commits with limit ($state, $branch)" '
-		git rev-list --count -n 1 $branch >expect &&
-		git rev-list --use-bitmap-index --count -n 1 $branch >actual &&
-		test_cmp expect actual
-	'
-
-	test_expect_success "counting non-linear history ($state, $branch)" '
-		git rev-list --count other...second >expect &&
-		git rev-list --use-bitmap-index --count other...second >actual &&
-		test_cmp expect actual
-	'
-
-	test_expect_success "counting commits with limiting ($state, $branch)" '
-		git rev-list --count $branch -- 1.t >expect &&
-		git rev-list --use-bitmap-index --count $branch -- 1.t >actual &&
-		test_cmp expect actual
-	'
-
-	test_expect_success "counting objects via bitmap ($state, $branch)" '
-		git rev-list --count --objects $branch >expect &&
-		git rev-list --use-bitmap-index --count --objects $branch >actual &&
-		test_cmp expect actual
-	'
-
-	test_expect_success "enumerate commits ($state, $branch)" '
-		git rev-list --use-bitmap-index $branch >actual &&
-		git rev-list $branch >expect &&
-		test_bitmap_traversal --no-confirm-bitmaps expect actual
-	'
-
-	test_expect_success "enumerate --objects ($state, $branch)" '
-		git rev-list --objects --use-bitmap-index $branch >actual &&
-		git rev-list --objects $branch >expect &&
-		test_bitmap_traversal expect actual
-	'
-
-	test_expect_success "bitmap --objects handles non-commit objects ($state, $branch)" '
-		git rev-list --objects --use-bitmap-index $branch tagged-blob >actual &&
-		grep $blob actual
-	'
-}
-
-rev_list_tests () {
-	state=$1
-
-	for branch in "second" "other"
-	do
-		rev_list_tests_head
-	done
-}
-
-rev_list_tests 'full bitmap'
-
-test_expect_success 'clone from bitmapped repository' '
-	git clone --no-local --bare . clone.git &&
-	git rev-parse HEAD >expect &&
-	git --git-dir=clone.git rev-parse HEAD >actual &&
-	test_cmp expect actual
-'
-
-test_expect_success 'partial clone from bitmapped repository' '
-	test_config uploadpack.allowfilter true &&
-	git clone --no-local --bare --filter=blob:none . partial-clone.git &&
-	(
-		cd partial-clone.git &&
-		pack=$(echo objects/pack/*.pack) &&
-		git verify-pack -v "$pack" >have &&
-		awk "/blob/ { print \$1 }" <have >blobs &&
-		# we expect this single blob because of the direct ref
-		git rev-parse refs/tags/tagged-blob >expect &&
-		test_cmp expect blobs
-	)
-'
-
-test_expect_success 'setup further non-bitmapped commits' '
-	test_commit_bulk --id=further 10
-'
-
-rev_list_tests 'partial bitmap'
-
-test_expect_success 'fetch (partial 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
-'
+basic_bitmap_tests
 
 test_expect_success 'incremental repack fails when bitmaps are requested' '
 	test_commit more-1 &&
@@ -461,40 +280,6 @@
 	test_i18ngrep corrupted.bitmap.index stderr
 '
 
-test_expect_success 'enumerating progress counts pack-reused objects' '
-	count=$(git rev-list --objects --all --count) &&
-	git repack -adb &&
-
-	# check first with only reused objects; confirm that our progress
-	# showed the right number, and also that we did pack-reuse as expected.
-	# Check only the final "done" line of the meter (there may be an
-	# arbitrary number of intermediate lines ending with CR).
-	GIT_PROGRESS_DELAY=0 \
-		git pack-objects --all --stdout --progress \
-		</dev/null >/dev/null 2>stderr &&
-	grep "Enumerating objects: $count, done" stderr &&
-	grep "pack-reused $count" stderr &&
-
-	# now the same but with one non-reused object
-	git commit --allow-empty -m "an extra commit object" &&
-	GIT_PROGRESS_DELAY=0 \
-		git pack-objects --all --stdout --progress \
-		</dev/null >/dev/null 2>stderr &&
-	grep "Enumerating objects: $((count+1)), done" stderr &&
-	grep "pack-reused $count" stderr
-'
-
-# have_delta <obj> <expected_base>
-#
-# Note that because this relies on cat-file, it might find _any_ copy of an
-# object in the repository. The caller is responsible for making sure
-# there's only one (e.g., via "repack -ad", or having just fetched a copy).
-have_delta () {
-	echo $2 >expect &&
-	echo $1 | git cat-file --batch-check="%(deltabase)" >actual &&
-	test_cmp expect actual
-}
-
 # Create a state of history with these properties:
 #
 #  - refs that allow a client to fetch some new history, while sharing some old
diff --git a/t/t5312-prune-corruption.sh b/t/t5312-prune-corruption.sh
index 11423b3..ea889c0 100755
--- a/t/t5312-prune-corruption.sh
+++ b/t/t5312-prune-corruption.sh
@@ -7,6 +7,9 @@
 bail out or to proceed using it as a reachable tip, but it is _not_
 OK to proceed as if it did not exist. Otherwise we might silently
 delete objects that cannot be recovered.
+
+Note that we do assert command failure in these cases, because that is
+what currently happens. If that changes, these tests should be revisited.
 '
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
@@ -18,39 +21,58 @@
 	git reflog expire --expire=all --all
 '
 
+create_bogus_ref () {
+	test_when_finished 'rm -f .git/refs/heads/bogus..name' &&
+	echo $bogus >.git/refs/heads/bogus..name
+}
+
 test_expect_success 'create history reachable only from a bogus-named ref' '
 	test_tick && git commit --allow-empty -m main &&
 	base=$(git rev-parse HEAD) &&
 	test_tick && git commit --allow-empty -m bogus &&
 	bogus=$(git rev-parse HEAD) &&
 	git cat-file commit $bogus >saved &&
-	echo $bogus >.git/refs/heads/bogus..name &&
 	git reset --hard HEAD^
 '
 
 test_expect_success 'pruning does not drop bogus object' '
 	test_when_finished "git hash-object -w -t commit saved" &&
-	test_might_fail git prune --expire=now &&
-	verbose git cat-file -e $bogus
+	create_bogus_ref &&
+	test_must_fail git prune --expire=now &&
+	git cat-file -e $bogus
 '
 
 test_expect_success 'put bogus object into pack' '
 	git tag reachable $bogus &&
 	git repack -ad &&
 	git tag -d reachable &&
-	verbose git cat-file -e $bogus
+	git cat-file -e $bogus
 '
 
+test_expect_success 'non-destructive repack bails on bogus ref' '
+	create_bogus_ref &&
+	test_must_fail git repack -adk
+'
+
+test_expect_success 'GIT_REF_PARANOIA=0 overrides safety' '
+	create_bogus_ref &&
+	GIT_REF_PARANOIA=0 git repack -adk
+'
+
+
 test_expect_success 'destructive repack keeps packed object' '
-	test_might_fail git repack -Ad --unpack-unreachable=now &&
-	verbose git cat-file -e $bogus &&
-	test_might_fail git repack -ad &&
-	verbose git cat-file -e $bogus
+	create_bogus_ref &&
+	test_must_fail git repack -Ad --unpack-unreachable=now &&
+	git cat-file -e $bogus &&
+	test_must_fail git repack -ad &&
+	git cat-file -e $bogus
 '
 
-# subsequent tests will have different corruptions
-test_expect_success 'clean up bogus ref' '
-	rm .git/refs/heads/bogus..name
+test_expect_success 'destructive repack not confused by dangling symref' '
+	test_when_finished "git symbolic-ref -d refs/heads/dangling" &&
+	git symbolic-ref refs/heads/dangling refs/heads/does-not-exist &&
+	git repack -ad &&
+	test_must_fail git cat-file -e $bogus
 '
 
 # We create two new objects here, "one" and "two". Our
@@ -77,8 +99,8 @@
 
 test_expect_success 'pruning with a corrupted tip does not drop history' '
 	test_when_finished "git hash-object -w -t commit saved" &&
-	test_might_fail git prune --expire=now &&
-	verbose git cat-file -e $recoverable
+	test_must_fail git prune --expire=now &&
+	git cat-file -e $recoverable
 '
 
 test_expect_success 'pack-refs does not silently delete broken loose ref' '
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index af88f80..295c5bd 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -5,6 +5,25 @@
 
 GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS=0
 
+test_expect_success 'usage' '
+	test_expect_code 129 git commit-graph write blah 2>err &&
+	test_expect_code 129 git commit-graph write verify
+'
+
+test_expect_success 'usage shown without sub-command' '
+	test_expect_code 129 git commit-graph 2>err &&
+	! grep error: err
+'
+
+test_expect_success 'usage shown with an error on unknown sub-command' '
+	cat >expect <<-\EOF &&
+	error: unrecognized subcommand: unknown
+	EOF
+	test_expect_code 129 git commit-graph unknown 2>stderr &&
+	grep error stderr >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'setup full repo' '
 	mkdir full &&
 	cd "$TRASH_DIRECTORY/full" &&
diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh
index 3d4d9f1..a3c72b6 100755
--- a/t/t5319-multi-pack-index.sh
+++ b/t/t5319-multi-pack-index.sh
@@ -168,18 +168,33 @@
 
 compare_results_with_midx "two packs"
 
+test_expect_success 'write midx with --stdin-packs' '
+	rm -fr $objdir/pack/multi-pack-index &&
+
+	idx="$(find $objdir/pack -name "test-2-*.idx")" &&
+	basename "$idx" >in &&
+
+	git multi-pack-index write --stdin-packs <in &&
+
+	test-tool read-midx $objdir | grep "\.idx$" >packs &&
+
+	test_cmp packs in
+'
+
+compare_results_with_midx "mixed mode (one pack + extra)"
+
 test_expect_success 'write progress off for redirected stderr' '
 	git multi-pack-index --object-dir=$objdir write 2>err &&
 	test_line_count = 0 err
 '
 
 test_expect_success 'write force progress on for stderr' '
-	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir --progress write 2>err &&
+	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir write --progress 2>err &&
 	test_file_not_empty err
 '
 
 test_expect_success 'write with the --no-progress option' '
-	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir --no-progress write 2>err &&
+	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir write --no-progress 2>err &&
 	test_line_count = 0 err
 '
 
@@ -201,6 +216,34 @@
 
 compare_results_with_midx "twelve packs"
 
+test_expect_success 'multi-pack-index *.rev cleanup with --object-dir' '
+	git init repo &&
+	git clone -s repo alternate &&
+
+	test_when_finished "rm -rf repo alternate" &&
+
+	(
+		cd repo &&
+		test_commit base &&
+		git repack -d
+	) &&
+
+	ours="alternate/.git/objects/pack/multi-pack-index-123.rev" &&
+	theirs="repo/.git/objects/pack/multi-pack-index-abc.rev" &&
+	touch "$ours" "$theirs" &&
+
+	(
+		cd alternate &&
+		git multi-pack-index --object-dir ../repo/.git/objects write
+	) &&
+
+	# writing a midx in "repo" should not remove the .rev file in the
+	# alternate
+	test_path_is_file repo/.git/objects/pack/multi-pack-index &&
+	test_path_is_file $ours &&
+	test_path_is_missing $theirs
+'
+
 test_expect_success 'warn on improper hash version' '
 	git init --object-format=sha1 sha1 &&
 	(
@@ -277,6 +320,23 @@
 	)
 '
 
+test_expect_success 'preferred packs must be non-empty' '
+	test_when_finished rm -rf preferred.git &&
+	git init preferred.git &&
+	(
+		cd preferred.git &&
+
+		test_commit base &&
+		git repack -ad &&
+
+		empty="$(git pack-objects $objdir/pack/pack </dev/null)" &&
+
+		test_must_fail git multi-pack-index write \
+			--preferred-pack=pack-$empty.pack 2>err &&
+		grep "with no objects" err
+	)
+'
+
 test_expect_success 'verify multi-pack-index success' '
 	git multi-pack-index verify --object-dir=$objdir
 '
@@ -429,12 +489,12 @@
 '
 
 test_expect_success 'repack force progress on for stderr' '
-	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir --progress repack 2>err &&
+	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir repack --progress 2>err &&
 	test_file_not_empty err
 '
 
 test_expect_success 'repack with the --no-progress option' '
-	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir --no-progress repack 2>err &&
+	GIT_PROGRESS_DELAY=0 git multi-pack-index --object-dir=$objdir repack --no-progress 2>err &&
 	test_line_count = 0 err
 '
 
@@ -487,7 +547,8 @@
 compare_results_with_midx "after repack"
 
 test_expect_success 'multi-pack-index and pack-bitmap' '
-	git -c repack.writeBitmaps=true repack -ad &&
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
+		git -c repack.writeBitmaps=true repack -ad &&
 	git multi-pack-index write &&
 	git rev-list --test-bitmap HEAD
 '
@@ -537,7 +598,15 @@
 	idx64=objects64/pack/test-64-$pack64.idx &&
 	chmod u+w $idx64 &&
 	corrupt_data $idx64 $(test_oid idxoff) "\02" &&
-	midx64=$(git multi-pack-index --object-dir=objects64 write) &&
+	# objects64 is not a real repository, but can serve as an alternate
+	# anyway so we can write a MIDX into it
+	git init repo &&
+	test_when_finished "rm -fr repo" &&
+	(
+		cd repo &&
+		( cd ../objects64 && pwd ) >.git/objects/info/alternates &&
+		midx64=$(git multi-pack-index --object-dir=../objects64 write)
+	) &&
 	midx_read_expect 1 63 5 objects64 " large-offsets"
 '
 
@@ -618,7 +687,7 @@
 test_expect_success 'expire force progress on for stderr' '
 	(
 		cd dup &&
-		GIT_PROGRESS_DELAY=0 git multi-pack-index --progress expire 2>err &&
+		GIT_PROGRESS_DELAY=0 git multi-pack-index expire --progress 2>err &&
 		test_file_not_empty err
 	)
 '
@@ -626,7 +695,7 @@
 test_expect_success 'expire with the --no-progress option' '
 	(
 		cd dup &&
-		GIT_PROGRESS_DELAY=0 git multi-pack-index --no-progress expire 2>err &&
+		GIT_PROGRESS_DELAY=0 git multi-pack-index expire --no-progress 2>err &&
 		test_line_count = 0 err
 	)
 '
@@ -842,4 +911,9 @@
 	! test_i18ngrep "unrecognized subcommand" err
 '
 
+test_expect_success 'complains when run outside of a repository' '
+	nongit test_must_fail git multi-pack-index write 2>err &&
+	grep "not a git repository" err
+'
+
 test_done
diff --git a/t/t5326-multi-pack-bitmaps.sh b/t/t5326-multi-pack-bitmaps.sh
new file mode 100755
index 0000000..e187f90
--- /dev/null
+++ b/t/t5326-multi-pack-bitmaps.sh
@@ -0,0 +1,398 @@
+#!/bin/sh
+
+test_description='exercise basic multi-pack bitmap functionality'
+. ./test-lib.sh
+. "${TEST_DIRECTORY}/lib-bitmap.sh"
+
+# We'll be writing our own midx and bitmaps, so avoid getting confused by the
+# automatic ones.
+GIT_TEST_MULTI_PACK_INDEX=0
+GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0
+
+objdir=.git/objects
+midx=$objdir/pack/multi-pack-index
+
+# midx_pack_source <obj>
+midx_pack_source () {
+	test-tool read-midx --show-objects .git/objects | grep "^$1 " | cut -f2
+}
+
+setup_bitmap_history
+
+test_expect_success 'enable core.multiPackIndex' '
+	git config core.multiPackIndex true
+'
+
+test_expect_success 'create single-pack midx with bitmaps' '
+	git repack -ad &&
+	git multi-pack-index write --bitmap &&
+	test_path_is_file $midx &&
+	test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+	test_path_is_file $midx-$(midx_checksum $objdir).rev
+'
+
+basic_bitmap_tests
+
+test_expect_success 'create new additional packs' '
+	for i in $(test_seq 1 16)
+	do
+		test_commit "$i" &&
+		git repack -d || return 1
+	done &&
+
+	git checkout -b other2 HEAD~8 &&
+	for i in $(test_seq 1 8)
+	do
+		test_commit "side-$i" &&
+		git repack -d || return 1
+	done &&
+	git checkout second
+'
+
+test_expect_success 'create multi-pack midx with bitmaps' '
+	git multi-pack-index write --bitmap &&
+
+	ls $objdir/pack/pack-*.pack >packs &&
+	test_line_count = 25 packs &&
+
+	test_path_is_file $midx &&
+	test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+	test_path_is_file $midx-$(midx_checksum $objdir).rev
+'
+
+basic_bitmap_tests
+
+test_expect_success '--no-bitmap is respected when bitmaps exist' '
+	git multi-pack-index write --bitmap &&
+
+	test_commit respect--no-bitmap &&
+	git repack -d &&
+
+	test_path_is_file $midx &&
+	test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+	test_path_is_file $midx-$(midx_checksum $objdir).rev &&
+
+	git multi-pack-index write --no-bitmap &&
+
+	test_path_is_file $midx &&
+	test_path_is_missing $midx-$(midx_checksum $objdir).bitmap &&
+	test_path_is_missing $midx-$(midx_checksum $objdir).rev
+'
+
+test_expect_success 'setup midx with base from later pack' '
+	# Write a and b so that "a" is a delta on top of base "b", since Git
+	# prefers to delete contents out of a base rather than add to a shorter
+	# object.
+	test_seq 1 128 >a &&
+	test_seq 1 130 >b &&
+
+	git add a b &&
+	git commit -m "initial commit" &&
+
+	a=$(git rev-parse HEAD:a) &&
+	b=$(git rev-parse HEAD:b) &&
+
+	# In the first pack, "a" is stored as a delta to "b".
+	p1=$(git pack-objects .git/objects/pack/pack <<-EOF
+	$a
+	$b
+	EOF
+	) &&
+
+	# In the second pack, "a" is missing, and "b" is not a delta nor base to
+	# any other object.
+	p2=$(git pack-objects .git/objects/pack/pack <<-EOF
+	$b
+	$(git rev-parse HEAD)
+	$(git rev-parse HEAD^{tree})
+	EOF
+	) &&
+
+	git prune-packed &&
+	# Use the second pack as the preferred source, so that "b" occurs
+	# earlier in the MIDX object order, rendering "a" unusable for pack
+	# reuse.
+	git multi-pack-index write --bitmap --preferred-pack=pack-$p2.idx &&
+
+	have_delta $a $b &&
+	test $(midx_pack_source $a) != $(midx_pack_source $b)
+'
+
+rev_list_tests 'full bitmap with backwards delta'
+
+test_expect_success 'clone with bitmaps enabled' '
+	git clone --no-local --bare . clone-reverse-delta.git &&
+	test_when_finished "rm -fr clone-reverse-delta.git" &&
+
+	git rev-parse HEAD >expect &&
+	git --git-dir=clone-reverse-delta.git rev-parse HEAD >actual &&
+	test_cmp expect actual
+'
+
+bitmap_reuse_tests() {
+	from=$1
+	to=$2
+
+	test_expect_success "setup pack reuse tests ($from -> $to)" '
+		rm -fr repo &&
+		git init repo &&
+		(
+			cd repo &&
+			test_commit_bulk 16 &&
+			git tag old-tip &&
+
+			git config core.multiPackIndex true &&
+			if test "MIDX" = "$from"
+			then
+				git repack -Ad &&
+				git multi-pack-index write --bitmap
+			else
+				git repack -Adb
+			fi
+		)
+	'
+
+	test_expect_success "build bitmap from existing ($from -> $to)" '
+		(
+			cd repo &&
+			test_commit_bulk --id=further 16 &&
+			git tag new-tip &&
+
+			if test "MIDX" = "$to"
+			then
+				git repack -d &&
+				git multi-pack-index write --bitmap
+			else
+				git repack -Adb
+			fi
+		)
+	'
+
+	test_expect_success "verify resulting bitmaps ($from -> $to)" '
+		(
+			cd repo &&
+			git for-each-ref &&
+			git rev-list --test-bitmap refs/tags/old-tip &&
+			git rev-list --test-bitmap refs/tags/new-tip
+		)
+	'
+}
+
+bitmap_reuse_tests 'pack' 'MIDX'
+bitmap_reuse_tests 'MIDX' 'pack'
+bitmap_reuse_tests 'MIDX' 'MIDX'
+
+test_expect_success 'missing object closure fails gracefully' '
+	rm -fr repo &&
+	git init repo &&
+	test_when_finished "rm -fr repo" &&
+	(
+		cd repo &&
+
+		test_commit loose &&
+		test_commit packed &&
+
+		# 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_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 'setup partial bitmaps' '
+	test_commit packed &&
+	git repack &&
+	test_commit loose &&
+	git multi-pack-index write --bitmap 2>err &&
+	test_path_is_file $midx &&
+	test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+	test_path_is_file $midx-$(midx_checksum $objdir).rev
+'
+
+basic_bitmap_tests HEAD~
+
+test_expect_success 'removing a MIDX clears stale bitmaps' '
+	rm -fr repo &&
+	git init repo &&
+	test_when_finished "rm -fr repo" &&
+	(
+		cd repo &&
+		test_commit base &&
+		git repack &&
+		git multi-pack-index write --bitmap &&
+
+		# Write a MIDX and bitmap; remove the MIDX but leave the bitmap.
+		stale_bitmap=$midx-$(midx_checksum $objdir).bitmap &&
+		stale_rev=$midx-$(midx_checksum $objdir).rev &&
+		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_file $midx-$(midx_checksum $objdir).rev &&
+		test_path_is_missing $stale_bitmap &&
+		test_path_is_missing $stale_rev
+	)
+'
+
+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_path_is_file $midx-$(midx_checksum $objdir).rev &&
+
+		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 $midx-$(midx_checksum $objdir).rev &&
+		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 $midx-$(midx_checksum $objdir).rev &&
+		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 &&
+
+		(
+			grep -vf before commits.raw &&
+			# mark missing commits as preferred
+			sed "s/^/+/" before
+		) >snapshot &&
+
+		rm -fr $midx-$(midx_checksum $objdir).bitmap &&
+		rm -fr $midx-$(midx_checksum $objdir).rev &&
+		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 &&
+
+		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_done
diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 4db8edd..8212ca5 100755
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -662,10 +662,10 @@
 
 test_expect_success 'allow deleting an invalid remote ref' '
 
-	mk_test testrepo heads/main &&
+	mk_test testrepo heads/branch &&
 	rm -f testrepo/.git/objects/??/* &&
-	git push testrepo :refs/heads/main &&
-	(cd testrepo && test_must_fail git rev-parse --verify refs/heads/main)
+	git push testrepo :refs/heads/branch &&
+	(cd testrepo && test_must_fail git rev-parse --verify refs/heads/branch)
 
 '
 
@@ -706,25 +706,26 @@
 '
 
 test_expect_success 'deleting dangling ref triggers hooks with correct args' '
-	mk_test_with_hooks testrepo heads/main &&
+	mk_test_with_hooks testrepo heads/branch &&
+	orig=$(git -C testrepo rev-parse refs/heads/branch) &&
 	rm -f testrepo/.git/objects/??/* &&
-	git push testrepo :refs/heads/main &&
+	git push testrepo :refs/heads/branch &&
 	(
 		cd testrepo/.git &&
 		cat >pre-receive.expect <<-EOF &&
-		$ZERO_OID $ZERO_OID refs/heads/main
+		$orig $ZERO_OID refs/heads/branch
 		EOF
 
 		cat >update.expect <<-EOF &&
-		refs/heads/main $ZERO_OID $ZERO_OID
+		refs/heads/branch $orig $ZERO_OID
 		EOF
 
 		cat >post-receive.expect <<-EOF &&
-		$ZERO_OID $ZERO_OID refs/heads/main
+		$orig $ZERO_OID refs/heads/branch
 		EOF
 
 		cat >post-update.expect <<-EOF &&
-		refs/heads/main
+		refs/heads/branch
 		EOF
 
 		test_cmp pre-receive.expect pre-receive.actual &&
diff --git a/t/t5520-pull.sh b/t/t5520-pull.sh
index 672001a..93ecfcd 100755
--- a/t/t5520-pull.sh
+++ b/t/t5520-pull.sh
@@ -546,15 +546,6 @@
 	test_cmp expect actual
 '
 
-test_expect_success REBASE_P \
-	'pull.rebase=preserve rebases and merges keep-merge' '
-	git reset --hard before-preserve-rebase &&
-	test_config pull.rebase preserve &&
-	git pull . copy &&
-	test_cmp_rev HEAD^^ copy &&
-	test_cmp_rev HEAD^2 keep-merge
-'
-
 test_expect_success 'pull.rebase=interactive' '
 	write_script "$TRASH_DIRECTORY/fake-editor" <<-\EOF &&
 	echo I was here >fake.out &&
@@ -598,7 +589,7 @@
 
 test_expect_success '--rebase=true rebases and flattens keep-merge' '
 	git reset --hard before-preserve-rebase &&
-	test_config pull.rebase preserve &&
+	test_config pull.rebase merges &&
 	git pull --rebase=true . copy &&
 	test_cmp_rev HEAD^^ copy &&
 	echo file3 >expect &&
@@ -606,23 +597,14 @@
 	test_cmp expect actual
 '
 
-test_expect_success REBASE_P \
-	'--rebase=preserve rebases and merges keep-merge' '
-	git reset --hard before-preserve-rebase &&
-	test_config pull.rebase true &&
-	git pull --rebase=preserve . copy &&
-	test_cmp_rev HEAD^^ copy &&
-	test_cmp_rev HEAD^2 keep-merge
-'
-
 test_expect_success '--rebase=invalid fails' '
 	git reset --hard before-preserve-rebase &&
 	test_must_fail git pull --rebase=invalid . copy
 '
 
-test_expect_success '--rebase overrides pull.rebase=preserve and flattens keep-merge' '
+test_expect_success '--rebase overrides pull.rebase=merges and flattens keep-merge' '
 	git reset --hard before-preserve-rebase &&
-	test_config pull.rebase preserve &&
+	test_config pull.rebase merges &&
 	git pull --rebase . copy &&
 	test_cmp_rev HEAD^^ copy &&
 	echo file3 >expect &&
diff --git a/t/t5526-fetch-submodules.sh b/t/t5526-fetch-submodules.sh
index ed11569..2dc75b8 100755
--- a/t/t5526-fetch-submodules.sh
+++ b/t/t5526-fetch-submodules.sh
@@ -6,6 +6,9 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=master
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB=1
+export GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB
+
 . ./test-lib.sh
 
 pwd=$(pwd)
diff --git a/t/t5531-deep-submodule-push.sh b/t/t5531-deep-submodule-push.sh
index d573ca4..3f58b51 100755
--- a/t/t5531-deep-submodule-push.sh
+++ b/t/t5531-deep-submodule-push.sh
@@ -5,6 +5,9 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB=1
+export GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB
+
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t5534-push-signed.sh b/t/t5534-push-signed.sh
index bba768f..24d374a 100755
--- a/t/t5534-push-signed.sh
+++ b/t/t5534-push-signed.sh
@@ -137,6 +137,53 @@
 	test_cmp expect dst/push-cert-status
 '
 
+test_expect_success GPGSSH 'ssh signed push sends push certificate' '
+	prepare_dst &&
+	mkdir -p dst/.git/hooks &&
+	git -C dst config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git -C dst config receive.certnonceseed sekrit &&
+	write_script dst/.git/hooks/post-receive <<-\EOF &&
+	# discard the update list
+	cat >/dev/null
+	# record the push certificate
+	if test -n "${GIT_PUSH_CERT-}"
+	then
+		git cat-file blob $GIT_PUSH_CERT >../push-cert
+	fi &&
+
+	cat >../push-cert-status <<E_O_F
+	SIGNER=${GIT_PUSH_CERT_SIGNER-nobody}
+	KEY=${GIT_PUSH_CERT_KEY-nokey}
+	STATUS=${GIT_PUSH_CERT_STATUS-nostatus}
+	NONCE_STATUS=${GIT_PUSH_CERT_NONCE_STATUS-nononcestatus}
+	NONCE=${GIT_PUSH_CERT_NONCE-nononce}
+	E_O_F
+
+	EOF
+
+	test_config gpg.format ssh &&
+	test_config user.signingkey "${GPGSSH_KEY_PRIMARY}" &&
+	FINGERPRINT=$(ssh-keygen -lf "${GPGSSH_KEY_PRIMARY}" | awk "{print \$2;}") &&
+	git push --signed dst noop ff +noff &&
+
+	(
+		cat <<-\EOF &&
+		SIGNER=principal with number 1
+		KEY=FINGERPRINT
+		STATUS=G
+		NONCE_STATUS=OK
+		EOF
+		sed -n -e "s/^nonce /NONCE=/p" -e "/^$/q" dst/push-cert
+	) | sed -e "s|FINGERPRINT|$FINGERPRINT|" >expect &&
+
+	noop=$(git rev-parse noop) &&
+	ff=$(git rev-parse ff) &&
+	noff=$(git rev-parse noff) &&
+	grep "$noop $ff refs/heads/ff" dst/push-cert &&
+	grep "$noop $noff refs/heads/noff" dst/push-cert &&
+	test_cmp expect dst/push-cert-status
+'
+
 test_expect_success GPG 'inconsistent push options in signed push not allowed' '
 	# First, invoke receive-pack with dummy input to obtain its preamble.
 	prepare_dst &&
@@ -276,6 +323,60 @@
 	test_cmp expect dst/push-cert-status
 '
 
+test_expect_success GPGSSH 'fail without key and heed user.signingkey ssh' '
+	test_config gpg.format ssh &&
+	prepare_dst &&
+	mkdir -p dst/.git/hooks &&
+	git -C dst config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git -C dst config receive.certnonceseed sekrit &&
+	write_script dst/.git/hooks/post-receive <<-\EOF &&
+	# discard the update list
+	cat >/dev/null
+	# record the push certificate
+	if test -n "${GIT_PUSH_CERT-}"
+	then
+		git cat-file blob $GIT_PUSH_CERT >../push-cert
+	fi &&
+
+	cat >../push-cert-status <<E_O_F
+	SIGNER=${GIT_PUSH_CERT_SIGNER-nobody}
+	KEY=${GIT_PUSH_CERT_KEY-nokey}
+	STATUS=${GIT_PUSH_CERT_STATUS-nostatus}
+	NONCE_STATUS=${GIT_PUSH_CERT_NONCE_STATUS-nononcestatus}
+	NONCE=${GIT_PUSH_CERT_NONCE-nononce}
+	E_O_F
+
+	EOF
+
+	test_config user.email hasnokey@nowhere.com &&
+	test_config gpg.format ssh &&
+	test_config user.signingkey "" &&
+	(
+		sane_unset GIT_COMMITTER_EMAIL &&
+		test_must_fail git push --signed dst noop ff +noff
+	) &&
+	test_config user.signingkey "${GPGSSH_KEY_PRIMARY}" &&
+	FINGERPRINT=$(ssh-keygen -lf "${GPGSSH_KEY_PRIMARY}" | awk "{print \$2;}") &&
+	git push --signed dst noop ff +noff &&
+
+	(
+		cat <<-\EOF &&
+		SIGNER=principal with number 1
+		KEY=FINGERPRINT
+		STATUS=G
+		NONCE_STATUS=OK
+		EOF
+		sed -n -e "s/^nonce /NONCE=/p" -e "/^$/q" dst/push-cert
+	) | sed -e "s|FINGERPRINT|$FINGERPRINT|" >expect &&
+
+	noop=$(git rev-parse noop) &&
+	ff=$(git rev-parse ff) &&
+	noff=$(git rev-parse noff) &&
+	grep "$noop $ff refs/heads/ff" dst/push-cert &&
+	grep "$noop $noff refs/heads/noff" dst/push-cert &&
+	test_cmp expect dst/push-cert-status
+'
+
 test_expect_success GPG 'failed atomic push does not execute GPG' '
 	prepare_dst &&
 	git -C dst config receive.certnonceseed sekrit &&
diff --git a/t/t5541-http-push-smart.sh b/t/t5541-http-push-smart.sh
index c024fa2..8ca50f8 100755
--- a/t/t5541-http-push-smart.sh
+++ b/t/t5541-http-push-smart.sh
@@ -509,4 +509,20 @@
 	test_i18ngrep ! "^hint: " decoded
 '
 
+test_expect_success 'report error server does not provide ref status' '
+	git init "$HTTPD_DOCUMENT_ROOT_PATH/no_report" &&
+	git -C "$HTTPD_DOCUMENT_ROOT_PATH/no_report" config http.receivepack true &&
+	test_must_fail git push --porcelain \
+		$HTTPD_URL_USER_PASS/smart/no_report \
+		HEAD:refs/tags/will-fail >actual &&
+	test_must_fail git -C "$HTTPD_DOCUMENT_ROOT_PATH/no_report" \
+		rev-parse --verify refs/tags/will-fail &&
+	cat >expect <<-EOF &&
+	To $HTTPD_URL/smart/no_report
+	!	HEAD:refs/tags/will-fail	[remote failure] (remote failed to report status)
+	Done
+	EOF
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t5545-push-options.sh b/t/t5545-push-options.sh
index 58c7add..2142283 100755
--- a/t/t5545-push-options.sh
+++ b/t/t5545-push-options.sh
@@ -5,6 +5,9 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB=1
+export GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB
+
 . ./test-lib.sh
 
 mk_repo_pair () {
diff --git a/t/t5551-http-fetch-smart.sh b/t/t5551-http-fetch-smart.sh
index 4e54226..f92c79c 100755
--- a/t/t5551-http-fetch-smart.sh
+++ b/t/t5551-http-fetch-smart.sh
@@ -558,4 +558,13 @@
 	expect_askpass both user@host
 '
 
+test_expect_success 'client falls back from v2 to v0 to match server' '
+	GIT_TRACE_PACKET=$PWD/trace \
+	GIT_TEST_PROTOCOL_VERSION=2 \
+	git clone $HTTPD_URL/smart_v0/repo.git repo-v0 &&
+	# check for v0; there the HEAD symref is communicated in the capability
+	# line; v2 uses a different syntax on each ref advertisement line
+	grep symref=HEAD:refs/heads/ trace
+'
+
 test_done
diff --git a/t/t5555-http-smart-common.sh b/t/t5555-http-smart-common.sh
new file mode 100755
index 0000000..49faf5e
--- /dev/null
+++ b/t/t5555-http-smart-common.sh
@@ -0,0 +1,161 @@
+#!/bin/sh
+
+test_description='test functionality common to smart fetch & push'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	test_commit --no-tag initial
+'
+
+test_expect_success 'git upload-pack --http-backend-info-refs and --advertise-refs are aliased' '
+	git upload-pack --http-backend-info-refs . >expected 2>err.expected &&
+	git upload-pack --advertise-refs . >actual 2>err.actual &&
+	test_cmp err.expected err.actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'git receive-pack --http-backend-info-refs and --advertise-refs are aliased' '
+	git receive-pack --http-backend-info-refs . >expected 2>err.expected &&
+	git receive-pack --advertise-refs . >actual 2>err.actual &&
+	test_cmp err.expected err.actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'git upload-pack --advertise-refs' '
+	cat >expect <<-EOF &&
+	$(git rev-parse HEAD) HEAD
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	# We only care about GIT_PROTOCOL, not GIT_TEST_PROTOCOL_VERSION
+	sane_unset GIT_PROTOCOL &&
+	GIT_TEST_PROTOCOL_VERSION=2 \
+	git upload-pack --advertise-refs . >out 2>err &&
+
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect &&
+
+	# The --advertise-refs alias works
+	git upload-pack --advertise-refs . >out 2>err &&
+
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+'
+
+test_expect_success 'git upload-pack --advertise-refs: v0' '
+	# With no specified protocol
+	cat >expect <<-EOF &&
+	$(git rev-parse HEAD) HEAD
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	git upload-pack --advertise-refs . >out 2>err &&
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect &&
+
+	# With explicit v0
+	GIT_PROTOCOL=version=0 \
+	git upload-pack --advertise-refs . >out 2>err &&
+	test-tool pkt-line unpack <out >actual 2>err &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+
+'
+
+test_expect_success 'git receive-pack --advertise-refs: v0' '
+	# With no specified protocol
+	cat >expect <<-EOF &&
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	git receive-pack --advertise-refs . >out 2>err &&
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect &&
+
+	# With explicit v0
+	GIT_PROTOCOL=version=0 \
+	git receive-pack --advertise-refs . >out 2>err &&
+	test-tool pkt-line unpack <out >actual 2>err &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+
+'
+
+test_expect_success 'git upload-pack --advertise-refs: v1' '
+	# With no specified protocol
+	cat >expect <<-EOF &&
+	version 1
+	$(git rev-parse HEAD) HEAD
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	GIT_PROTOCOL=version=1 \
+	git upload-pack --advertise-refs . >out &&
+
+	test-tool pkt-line unpack <out >actual 2>err &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+'
+
+test_expect_success 'git receive-pack --advertise-refs: v1' '
+	# With no specified protocol
+	cat >expect <<-EOF &&
+	version 1
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	GIT_PROTOCOL=version=1 \
+	git receive-pack --advertise-refs . >out &&
+
+	test-tool pkt-line unpack <out >actual 2>err &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+'
+
+test_expect_success 'git upload-pack --advertise-refs: v2' '
+	cat >expect <<-EOF &&
+	version 2
+	agent=FAKE
+	ls-refs=unborn
+	fetch=shallow wait-for-done
+	server-option
+	object-format=$(test_oid algo)
+	object-info
+	0000
+	EOF
+
+	GIT_PROTOCOL=version=2 \
+	GIT_USER_AGENT=FAKE \
+	git upload-pack --advertise-refs . >out 2>err &&
+
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+'
+
+test_expect_success 'git receive-pack --advertise-refs: v2' '
+	# There is no v2 yet for receive-pack, implicit v0
+	cat >expect <<-EOF &&
+	$(git rev-parse HEAD) $(git symbolic-ref HEAD)
+	0000
+	EOF
+
+	GIT_PROTOCOL=version=2 \
+	git receive-pack --advertise-refs . >out 2>err &&
+
+	test-tool pkt-line unpack <out >actual &&
+	test_must_be_empty err &&
+	test_cmp actual expect
+'
+
+test_done
diff --git a/t/t5572-pull-submodule.sh b/t/t5572-pull-submodule.sh
index 4f92a11..fa6b4cc 100755
--- a/t/t5572-pull-submodule.sh
+++ b/t/t5572-pull-submodule.sh
@@ -2,6 +2,9 @@
 
 test_description='pull can handle submodules'
 
+GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB=1
+export GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB
+
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-submodule-update.sh
 
diff --git a/t/t5580-unc-paths.sh b/t/t5580-unc-paths.sh
index cd803ae..cd7604f 100755
--- a/t/t5580-unc-paths.sh
+++ b/t/t5580-unc-paths.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
 
 if test_have_prereq CYGWIN
diff --git a/t/t5600-clone-fail-cleanup.sh b/t/t5600-clone-fail-cleanup.sh
index 5bf1026..34b3df4 100755
--- a/t/t5600-clone-fail-cleanup.sh
+++ b/t/t5600-clone-fail-cleanup.sh
@@ -35,7 +35,9 @@
 '
 
 test_expect_success 'create objects in repo for later corruption' '
-	test_commit -C foo file
+	test_commit -C foo file &&
+	git -C foo checkout --detach &&
+	test_commit -C foo detached
 '
 
 # source repository given to git clone should be relative to the
diff --git a/t/t5606-clone-options.sh b/t/t5606-clone-options.sh
index 3a595c0..d822153 100755
--- a/t/t5606-clone-options.sh
+++ b/t/t5606-clone-options.sh
@@ -16,6 +16,18 @@
 
 '
 
+test_expect_success 'submodule.stickyRecursiveClone flag manipulates submodule.recurse value' '
+
+	test_config_global submodule.stickyRecursiveClone true &&
+	git clone --recurse-submodules parent clone_recurse_true &&
+	test_cmp_config -C clone_recurse_true true submodule.recurse &&
+
+	test_config_global submodule.stickyRecursiveClone false &&
+	git clone --recurse-submodules parent clone_recurse_false &&
+	test_expect_code 1 git -C clone_recurse_false config --get submodule.recurse
+
+'
+
 test_expect_success 'clone -o' '
 
 	git clone -o foo parent clone-o &&
diff --git a/t/t5607-clone-bundle.sh b/t/t5607-clone-bundle.sh
index ed0d911..51705aa 100755
--- a/t/t5607-clone-bundle.sh
+++ b/t/t5607-clone-bundle.sh
@@ -91,7 +91,8 @@
 
 	git fetch long-subject-bundle.bdl &&
 
-	if ! test_have_prereq SHA1
+	algo=$(test_oid algo) &&
+	if test "$algo" != sha1
 	then
 		echo "@object-format=sha256"
 	fi >expect &&
@@ -100,7 +101,7 @@
 	$(git rev-parse HEAD) HEAD
 	EOF
 
-	if test_have_prereq SHA1
+	if test "$algo" = sha1
 	then
 		head -n 3 long-subject-bundle.bdl
 	else
diff --git a/t/t5615-alternate-env.sh b/t/t5615-alternate-env.sh
index b4905b8..83513e4 100755
--- a/t/t5615-alternate-env.sh
+++ b/t/t5615-alternate-env.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='handling of alternates in environment variables'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 check_obj () {
diff --git a/t/t5701-git-serve.sh b/t/t5701-git-serve.sh
index 930721f..aa1827d 100755
--- a/t/t5701-git-serve.sh
+++ b/t/t5701-git-serve.sh
@@ -72,6 +72,37 @@
 	test_i18ngrep "invalid command" err
 '
 
+test_expect_success 'request capability as command' '
+	test-tool pkt-line pack >in <<-EOF &&
+	command=agent
+	object-format=$(test_oid algo)
+	0000
+	EOF
+	test_must_fail test-tool serve-v2 --stateless-rpc 2>err <in &&
+	grep invalid.command.*agent err
+'
+
+test_expect_success 'request command as capability' '
+	test-tool pkt-line pack >in <<-EOF &&
+	command=ls-refs
+	object-format=$(test_oid algo)
+	fetch
+	0000
+	EOF
+	test_must_fail test-tool serve-v2 --stateless-rpc 2>err <in &&
+	grep unknown.capability err
+'
+
+test_expect_success 'requested command is command=value' '
+	test-tool pkt-line pack >in <<-EOF &&
+	command=ls-refs=whatever
+	object-format=$(test_oid algo)
+	0000
+	EOF
+	test_must_fail test-tool serve-v2 --stateless-rpc 2>err <in &&
+	grep invalid.command.*ls-refs=whatever err
+'
+
 test_expect_success 'wrong object-format' '
 	test-tool pkt-line pack >in <<-EOF &&
 	command=fetch
@@ -116,6 +147,19 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'ls-refs complains about unknown options' '
+	test-tool pkt-line pack >in <<-EOF &&
+	command=ls-refs
+	object-format=$(test_oid algo)
+	0001
+	no-such-arg
+	0000
+	EOF
+
+	test_must_fail test-tool serve-v2 --stateless-rpc 2>err <in &&
+	grep unexpected.line.*no-such-arg err
+'
+
 test_expect_success 'basic ref-prefixes' '
 	test-tool pkt-line pack >in <<-EOF &&
 	command=ls-refs
@@ -158,6 +202,37 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'ignore very large set of prefixes' '
+	# generate a large number of ref-prefixes that we expect
+	# to match nothing; the value here exceeds TOO_MANY_PREFIXES
+	# from ls-refs.c.
+	{
+		echo command=ls-refs &&
+		echo object-format=$(test_oid algo) &&
+		echo 0001 &&
+		perl -le "print \"ref-prefix refs/heads/\$_\" for (1..65536)" &&
+		echo 0000
+	} |
+	test-tool pkt-line pack >in &&
+
+	# and then confirm that we see unmatched prefixes anyway (i.e.,
+	# that the prefix was not applied).
+	cat >expect <<-EOF &&
+	$(git rev-parse HEAD) HEAD
+	$(git rev-parse refs/heads/dev) refs/heads/dev
+	$(git rev-parse refs/heads/main) refs/heads/main
+	$(git rev-parse refs/heads/release) refs/heads/release
+	$(git rev-parse refs/tags/annotated-tag) refs/tags/annotated-tag
+	$(git rev-parse refs/tags/one) refs/tags/one
+	$(git rev-parse refs/tags/two) refs/tags/two
+	0000
+	EOF
+
+	test-tool serve-v2 --stateless-rpc <in >out &&
+	test-tool pkt-line unpack <out >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'peel parameter' '
 	test-tool pkt-line pack >in <<-EOF &&
 	command=ls-refs
diff --git a/t/t6000-rev-list-misc.sh b/t/t6000-rev-list-misc.sh
index 12def7b..ef849e5 100755
--- a/t/t6000-rev-list-misc.sh
+++ b/t/t6000-rev-list-misc.sh
@@ -169,4 +169,35 @@
 	test_line_count = $count actual
 '
 
+test_expect_success 'rev-list --unsorted-input results in different sorting' '
+	git rev-list --unsorted-input HEAD HEAD~ >first &&
+	git rev-list --unsorted-input HEAD~ HEAD >second &&
+	! test_cmp first second &&
+	sort first >first.sorted &&
+	sort second >second.sorted &&
+	test_cmp first.sorted second.sorted
+'
+
+test_expect_success 'rev-list --unsorted-input incompatible with --no-walk' '
+	cat >expect <<-EOF &&
+		fatal: --no-walk is incompatible with --unsorted-input
+	EOF
+	test_must_fail git rev-list --unsorted-input --no-walk HEAD 2>error &&
+	test_cmp expect error &&
+	test_must_fail git rev-list --unsorted-input --no-walk=sorted HEAD 2>error &&
+	test_cmp expect error &&
+	test_must_fail git rev-list --unsorted-input --no-walk=unsorted HEAD 2>error &&
+	test_cmp expect error &&
+
+	cat >expect <<-EOF &&
+		fatal: --unsorted-input is incompatible with --no-walk
+	EOF
+	test_must_fail git rev-list --no-walk --unsorted-input HEAD 2>error &&
+	test_cmp expect error &&
+	test_must_fail git rev-list --no-walk=sorted --unsorted-input HEAD 2>error &&
+	test_cmp expect error &&
+	test_must_fail git rev-list --no-walk=unsorted --unsorted-input HEAD 2>error &&
+	test_cmp expect error
+'
+
 test_done
diff --git a/t/t6001-rev-list-graft.sh b/t/t6001-rev-list-graft.sh
index 90d93f7..7294147 100755
--- a/t/t6001-rev-list-graft.sh
+++ b/t/t6001-rev-list-graft.sh
@@ -23,7 +23,8 @@
 	git commit -a -m "Third in one history." &&
 	A2=$(git rev-parse --verify HEAD) &&
 
-	rm -f .git/refs/heads/main .git/index &&
+	git update-ref -d refs/heads/main &&
+	rm -f .git/index &&
 
 	echo >fileA fileA again &&
 	echo >subdir/fileB fileB again &&
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index a1baf4e..1be85d0 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -962,4 +962,22 @@
 	grep "$bad is the first bad commit" output
 '
 
+test_expect_success 'bisect run fails with exit code equals or greater than 128' '
+	write_script test_script.sh <<-\EOF &&
+	exit 128
+	EOF
+	test_must_fail git bisect run ./test_script.sh &&
+	write_script test_script.sh <<-\EOF &&
+	exit 255
+	EOF
+	test_must_fail git bisect run ./test_script.sh
+'
+
+test_expect_success 'bisect visualize with a filename with dash and space' '
+	echo "My test line" >>"./-hello 2" &&
+	git add -- "./-hello 2" &&
+	git commit --quiet -m "Add test line" -- "./-hello 2" &&
+	git bisect visualize -p -- "-hello 2"
+'
+
 test_done
diff --git a/t/t6050-replace.sh b/t/t6050-replace.sh
index e33d512..2500acc 100755
--- a/t/t6050-replace.sh
+++ b/t/t6050-replace.sh
@@ -132,7 +132,7 @@
 EOF
 
 test_expect_success 'tag replaced commit' '
-     git mktag <tag.sig >.git/refs/tags/mytag
+     git update-ref refs/tags/mytag $(git mktag <tag.sig)
 '
 
 test_expect_success '"git fsck" works' '
diff --git a/t/t6120-describe.sh b/t/t6120-describe.sh
index 1a501ee..bae2419 100755
--- a/t/t6120-describe.sh
+++ b/t/t6120-describe.sh
@@ -107,7 +107,8 @@
 check_describe tags/A --all A^0
 
 test_expect_success 'renaming tag A to Q locally produces a warning' "
-	mv .git/refs/tags/A .git/refs/tags/Q &&
+	git update-ref refs/tags/Q $(git rev-parse refs/tags/A) &&
+	git update-ref -d refs/tags/A &&
 	git describe HEAD 2>err >out &&
 	cat >expected <<-\EOF &&
 	warning: tag 'Q' is externally known as 'A'
@@ -135,7 +136,8 @@
 '
 
 test_expect_success 'rename tag Q back to A' '
-	mv .git/refs/tags/Q .git/refs/tags/A
+	git update-ref refs/tags/A $(git rev-parse refs/tags/Q) &&
+	git update-ref -d refs/tags/Q
 '
 
 test_expect_success 'pack tag refs' 'git pack-refs'
diff --git a/t/t6200-fmt-merge-msg.sh b/t/t6200-fmt-merge-msg.sh
index 44f55d9..06c5fb5 100755
--- a/t/t6200-fmt-merge-msg.sh
+++ b/t/t6200-fmt-merge-msg.sh
@@ -81,6 +81,16 @@
 	git tag -s -m signed-tag-msg signed-good-tag left
 '
 
+test_expect_success GPGSSH 'created ssh signed commit and tag' '
+	test_config gpg.format ssh &&
+	git checkout -b signed-ssh &&
+	touch file &&
+	git add file &&
+	git commit -m "ssh signed" -S"${GPGSSH_KEY_PRIMARY}" &&
+	git tag -s -u"${GPGSSH_KEY_PRIMARY}" -m signed-ssh-tag-msg signed-good-ssh-tag left &&
+	git tag -s -u"${GPGSSH_KEY_UNTRUSTED}" -m signed-ssh-tag-msg-untrusted signed-untrusted-ssh-tag left
+'
+
 test_expect_success 'message for merging local branch' '
 	echo "Merge branch ${apos}left${apos}" >expected &&
 
@@ -109,6 +119,24 @@
 	grep -E "^# gpg: Can${apos}t check signature: (public key not found|No public key)" actual
 '
 
+test_expect_success GPGSSH 'message for merging local tag signed by good ssh key' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git checkout main &&
+	git fetch . signed-good-ssh-tag &&
+	git fmt-merge-msg <.git/FETCH_HEAD >actual 2>&1 &&
+	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+	! grep "${GPGSSH_BAD_SIGNATURE}" actual
+'
+
+test_expect_success GPGSSH 'message for merging local tag signed by unknown ssh key' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git checkout main &&
+	git fetch . signed-untrusted-ssh-tag &&
+	git fmt-merge-msg <.git/FETCH_HEAD >actual 2>&1 &&
+	grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+	! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+	grep "${GPGSSH_KEY_NOT_TRUSTED}" actual
+'
 test_expect_success 'message for merging external branch' '
 	echo "Merge branch ${apos}left${apos} of $(pwd)" >expected &&
 
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index 05a15a9..80679d5 100755
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -137,6 +137,8 @@
 test_atom head numparent 0
 test_atom head object ''
 test_atom head type ''
+test_atom head raw "$(git cat-file commit refs/heads/main)
+"
 test_atom head '*objectname' ''
 test_atom head '*objecttype' ''
 test_atom head author 'A U Thor <author@example.com> 1151968724 +0200'
@@ -228,6 +230,15 @@
 '
 test_atom tag HEAD ' '
 
+test_expect_success 'basic atom: refs/tags/testtag *raw' '
+	git cat-file commit refs/tags/testtag^{} >expected &&
+	git for-each-ref --format="%(*raw)" refs/tags/testtag >actual &&
+	sanitize_pgp <expected >expected.clean &&
+	echo >>expected.clean &&
+	sanitize_pgp <actual >actual.clean &&
+	test_cmp expected.clean actual.clean
+'
+
 test_expect_success 'Check invalid atoms names are errors' '
 	test_must_fail git for-each-ref --format="%(INVALID)" refs/heads
 '
@@ -693,6 +704,15 @@
 test_atom refs/tags/signed-empty contents:signature "$sig"
 test_atom refs/tags/signed-empty contents "$sig"
 
+test_expect_success GPG 'basic atom: refs/tags/signed-empty raw' '
+	git cat-file tag refs/tags/signed-empty >expected &&
+	git for-each-ref --format="%(raw)" refs/tags/signed-empty >actual &&
+	sanitize_pgp <expected >expected.clean &&
+	echo >>expected.clean &&
+	sanitize_pgp <actual >actual.clean &&
+	test_cmp expected.clean actual.clean
+'
+
 test_atom refs/tags/signed-short subject 'subject line'
 test_atom refs/tags/signed-short subject:sanitize 'subject-line'
 test_atom refs/tags/signed-short contents:subject 'subject line'
@@ -702,6 +722,15 @@
 test_atom refs/tags/signed-short contents "subject line
 $sig"
 
+test_expect_success GPG 'basic atom: refs/tags/signed-short raw' '
+	git cat-file tag refs/tags/signed-short >expected &&
+	git for-each-ref --format="%(raw)" refs/tags/signed-short >actual &&
+	sanitize_pgp <expected >expected.clean &&
+	echo >>expected.clean &&
+	sanitize_pgp <actual >actual.clean &&
+	test_cmp expected.clean actual.clean
+'
+
 test_atom refs/tags/signed-long subject 'subject line'
 test_atom refs/tags/signed-long subject:sanitize 'subject-line'
 test_atom refs/tags/signed-long contents:subject 'subject line'
@@ -715,6 +744,15 @@
 body contents
 $sig"
 
+test_expect_success GPG 'basic atom: refs/tags/signed-long raw' '
+	git cat-file tag refs/tags/signed-long >expected &&
+	git for-each-ref --format="%(raw)" refs/tags/signed-long >actual &&
+	sanitize_pgp <expected >expected.clean &&
+	echo >>expected.clean &&
+	sanitize_pgp <actual >actual.clean &&
+	test_cmp expected.clean actual.clean
+'
+
 test_expect_success 'set up refs pointing to tree and blob' '
 	git update-ref refs/mytrees/first refs/heads/main^{tree} &&
 	git update-ref refs/myblobs/first refs/heads/main:one
@@ -727,6 +765,16 @@
 test_atom refs/mytrees/first contents:signature ""
 test_atom refs/mytrees/first contents ""
 
+test_expect_success 'basic atom: refs/mytrees/first raw' '
+	git cat-file tree refs/mytrees/first >expected &&
+	echo >>expected &&
+	git for-each-ref --format="%(raw)" refs/mytrees/first >actual &&
+	test_cmp expected actual &&
+	git cat-file -s refs/mytrees/first >expected &&
+	git for-each-ref --format="%(raw:size)" refs/mytrees/first >actual &&
+	test_cmp expected actual
+'
+
 test_atom refs/myblobs/first subject ""
 test_atom refs/myblobs/first contents:subject ""
 test_atom refs/myblobs/first body ""
@@ -734,6 +782,189 @@
 test_atom refs/myblobs/first contents:signature ""
 test_atom refs/myblobs/first contents ""
 
+test_expect_success 'basic atom: refs/myblobs/first raw' '
+	git cat-file blob refs/myblobs/first >expected &&
+	echo >>expected &&
+	git for-each-ref --format="%(raw)" refs/myblobs/first >actual &&
+	test_cmp expected actual &&
+	git cat-file -s refs/myblobs/first >expected &&
+	git for-each-ref --format="%(raw:size)" refs/myblobs/first >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'set up refs pointing to binary blob' '
+	printf "a\0b\0c" >blob1 &&
+	printf "a\0c\0b" >blob2 &&
+	printf "\0a\0b\0c" >blob3 &&
+	printf "abc" >blob4 &&
+	printf "\0 \0 \0 " >blob5 &&
+	printf "\0 \0a\0 " >blob6 &&
+	printf "  " >blob7 &&
+	>blob8 &&
+	obj=$(git hash-object -w blob1) &&
+	git update-ref refs/myblobs/blob1 "$obj" &&
+	obj=$(git hash-object -w blob2) &&
+	git update-ref refs/myblobs/blob2 "$obj" &&
+	obj=$(git hash-object -w blob3) &&
+	git update-ref refs/myblobs/blob3 "$obj" &&
+	obj=$(git hash-object -w blob4) &&
+	git update-ref refs/myblobs/blob4 "$obj" &&
+	obj=$(git hash-object -w blob5) &&
+	git update-ref refs/myblobs/blob5 "$obj" &&
+	obj=$(git hash-object -w blob6) &&
+	git update-ref refs/myblobs/blob6 "$obj" &&
+	obj=$(git hash-object -w blob7) &&
+	git update-ref refs/myblobs/blob7 "$obj" &&
+	obj=$(git hash-object -w blob8) &&
+	git update-ref refs/myblobs/blob8 "$obj"
+'
+
+test_expect_success 'Verify sorts with raw' '
+	cat >expected <<-EOF &&
+	refs/myblobs/blob8
+	refs/myblobs/blob5
+	refs/myblobs/blob6
+	refs/myblobs/blob3
+	refs/myblobs/blob7
+	refs/mytrees/first
+	refs/myblobs/first
+	refs/myblobs/blob1
+	refs/myblobs/blob2
+	refs/myblobs/blob4
+	refs/heads/main
+	EOF
+	git for-each-ref --format="%(refname)" --sort=raw \
+		refs/heads/main refs/myblobs/ refs/mytrees/first >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'Verify sorts with raw:size' '
+	cat >expected <<-EOF &&
+	refs/myblobs/blob8
+	refs/myblobs/first
+	refs/myblobs/blob7
+	refs/heads/main
+	refs/myblobs/blob4
+	refs/myblobs/blob1
+	refs/myblobs/blob2
+	refs/myblobs/blob3
+	refs/myblobs/blob5
+	refs/myblobs/blob6
+	refs/mytrees/first
+	EOF
+	git for-each-ref --format="%(refname)" --sort=raw:size \
+		refs/heads/main refs/myblobs/ refs/mytrees/first >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'validate raw atom with %(if:equals)' '
+	cat >expected <<-EOF &&
+	not equals
+	not equals
+	not equals
+	not equals
+	not equals
+	not equals
+	refs/myblobs/blob4
+	not equals
+	not equals
+	not equals
+	not equals
+	not equals
+	EOF
+	git for-each-ref --format="%(if:equals=abc)%(raw)%(then)%(refname)%(else)not equals%(end)" \
+		refs/myblobs/ refs/heads/ >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'validate raw atom with %(if:notequals)' '
+	cat >expected <<-EOF &&
+	refs/heads/ambiguous
+	refs/heads/main
+	refs/heads/newtag
+	refs/myblobs/blob1
+	refs/myblobs/blob2
+	refs/myblobs/blob3
+	equals
+	refs/myblobs/blob5
+	refs/myblobs/blob6
+	refs/myblobs/blob7
+	refs/myblobs/blob8
+	refs/myblobs/first
+	EOF
+	git for-each-ref --format="%(if:notequals=abc)%(raw)%(then)%(refname)%(else)equals%(end)" \
+		refs/myblobs/ refs/heads/ >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success 'empty raw refs with %(if)' '
+	cat >expected <<-EOF &&
+	refs/myblobs/blob1 not empty
+	refs/myblobs/blob2 not empty
+	refs/myblobs/blob3 not empty
+	refs/myblobs/blob4 not empty
+	refs/myblobs/blob5 not empty
+	refs/myblobs/blob6 not empty
+	refs/myblobs/blob7 empty
+	refs/myblobs/blob8 empty
+	refs/myblobs/first not empty
+	EOF
+	git for-each-ref --format="%(refname) %(if)%(raw)%(then)not empty%(else)empty%(end)" \
+		refs/myblobs/ >actual &&
+	test_cmp expected actual
+'
+
+test_expect_success '%(raw) with --python must fail' '
+	test_must_fail git for-each-ref --format="%(raw)" --python
+'
+
+test_expect_success '%(raw) with --tcl must fail' '
+	test_must_fail git for-each-ref --format="%(raw)" --tcl
+'
+
+test_expect_success '%(raw) with --perl' '
+	git for-each-ref --format="\$name= %(raw);
+print \"\$name\"" refs/myblobs/blob1 --perl | perl >actual &&
+	cmp blob1 actual &&
+	git for-each-ref --format="\$name= %(raw);
+print \"\$name\"" refs/myblobs/blob3 --perl | perl >actual &&
+	cmp blob3 actual &&
+	git for-each-ref --format="\$name= %(raw);
+print \"\$name\"" refs/myblobs/blob8 --perl | perl >actual &&
+	cmp blob8 actual &&
+	git for-each-ref --format="\$name= %(raw);
+print \"\$name\"" refs/myblobs/first --perl | perl >actual &&
+	cmp one actual &&
+	git cat-file tree refs/mytrees/first > expected &&
+	git for-each-ref --format="\$name= %(raw);
+print \"\$name\"" refs/mytrees/first --perl | perl >actual &&
+	cmp expected actual
+'
+
+test_expect_success '%(raw) with --shell must fail' '
+	test_must_fail git for-each-ref --format="%(raw)" --shell
+'
+
+test_expect_success '%(raw) with --shell and --sort=raw must fail' '
+	test_must_fail git for-each-ref --format="%(raw)" --sort=raw --shell
+'
+
+test_expect_success '%(raw:size) with --shell' '
+	git for-each-ref --format="%(raw:size)" | while read line
+	do
+		echo "'\''$line'\''" >>expect
+	done &&
+	git for-each-ref --format="%(raw:size)" --shell >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'for-each-ref --format compare with cat-file --batch' '
+	git rev-parse refs/mytrees/first | git cat-file --batch >expected &&
+	git for-each-ref --format="%(objectname) %(objecttype) %(objectsize)
+%(raw)" refs/mytrees/first >actual &&
+	test_cmp expected actual
+'
+
 test_expect_success 'set up multiple-sort tags' '
 	for when in 100000 200000
 	do
@@ -987,6 +1218,10 @@
 	test_cmp expect actual.clean
 '
 
+test_expect_success 'basic atom: rest must fail' '
+	test_must_fail git for-each-ref --format="%(rest)" refs/heads/main
+'
+
 test_expect_success 'trailer parsing not fooled by --- line' '
 	git commit --allow-empty -F - <<-\EOF &&
 	this is the subject
diff --git a/t/t6415-merge-dir-to-symlink.sh b/t/t6415-merge-dir-to-symlink.sh
index 2ce104a..2655e29 100755
--- a/t/t6415-merge-dir-to-symlink.sh
+++ b/t/t6415-merge-dir-to-symlink.sh
@@ -25,7 +25,8 @@
 	git reset --hard main &&
 	git rm --cached a/b &&
 	git commit -m "untracked symlink remains" &&
-	test_must_fail git checkout start^0
+	test_must_fail git checkout start^0 &&
+	git clean -fd    # Do not leave the untracked symlink in the way
 '
 
 test_expect_success 'a/b-2/c/d is kept when clobbering symlink b' '
@@ -34,7 +35,8 @@
 	git rm --cached a/b &&
 	git commit -m "untracked symlink remains" &&
 	git checkout -f start^0 &&
-	test_path_is_file a/b-2/c/d
+	test_path_is_file a/b-2/c/d &&
+	git clean -fd    # Do not leave the untracked symlink in the way
 '
 
 test_expect_success 'checkout should not have deleted a/b-2/c/d' '
diff --git a/t/t6424-merge-unrelated-index-changes.sh b/t/t6424-merge-unrelated-index-changes.sh
index 5e3779e..89dd544 100755
--- a/t/t6424-merge-unrelated-index-changes.sh
+++ b/t/t6424-merge-unrelated-index-changes.sh
@@ -132,6 +132,7 @@
 
 	# Make index match B
 	git diff C B -- | git apply --cached &&
+	test_when_finished "git clean -fd" &&  # Do not leave untracked around
 	# Merge B & F, with B as "head"
 	git merge-recursive A -- B F > out &&
 	test_i18ngrep "Already up to date" out
diff --git a/t/t6430-merge-recursive.sh b/t/t6430-merge-recursive.sh
index ffcc01f..a0efe7c 100755
--- a/t/t6430-merge-recursive.sh
+++ b/t/t6430-merge-recursive.sh
@@ -718,7 +718,9 @@
 	# merge-recursive prints in reverse order, but we do not care
 	sort <trees >expect &&
 	sed -n "s/^virtual //p" out | sort >actual &&
-	test_cmp expect actual
+	test_cmp expect actual &&
+
+	git clean -fd
 '
 
 test_expect_success 'merge-recursive internal merge resolves to the sameness' '
diff --git a/t/t6436-merge-overwrite.sh b/t/t6436-merge-overwrite.sh
index 84b4aac..c0b7bd7 100755
--- a/t/t6436-merge-overwrite.sh
+++ b/t/t6436-merge-overwrite.sh
@@ -68,7 +68,8 @@
 	git commit -m "rm c1.c" &&
 	cp important c1.c &&
 	test_must_fail git merge c1a &&
-	test_cmp important c1.c
+	test_cmp important c1.c &&
+	rm c1.c  # Do not leave untracked file in way of future tests
 '
 
 test_expect_success 'will not overwrite re-added file' '
diff --git a/t/t6437-submodule-merge.sh b/t/t6437-submodule-merge.sh
index e5e89c2..178413c 100755
--- a/t/t6437-submodule-merge.sh
+++ b/t/t6437-submodule-merge.sh
@@ -5,6 +5,9 @@
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB=1
+export GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB
+
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-merge.sh
 
diff --git a/t/t6500-gc.sh b/t/t6500-gc.sh
index 10c7ae7..c202126 100755
--- a/t/t6500-gc.sh
+++ b/t/t6500-gc.sh
@@ -241,7 +241,7 @@
 
 	# create a ref whose loose presence we can use to detect a pack-refs run
 	git update-ref refs/heads/should-be-loose HEAD &&
-	test_path_is_file .git/refs/heads/should-be-loose &&
+	(ls -1 .git/refs/heads .git/reftable >expect || true) &&
 
 	# now fake a concurrent gc that holds the lock; we can use our
 	# shell pid so that it looks valid.
@@ -258,7 +258,8 @@
 
 	# our gc should exit zero without doing anything
 	run_and_wait_for_auto_gc &&
-	test_path_is_file .git/refs/heads/should-be-loose
+	(ls -1 .git/refs/heads .git/reftable >actual || true) &&
+	test_cmp expect actual
 '
 
 # DO NOT leave a detached auto gc process running near the end of the
diff --git a/t/t7001-mv.sh b/t/t7001-mv.sh
index 25bb9bb..963356b 100755
--- a/t/t7001-mv.sh
+++ b/t/t7001-mv.sh
@@ -2,10 +2,11 @@
 
 test_description='git mv in subdirs'
 . ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-diff-data.sh
 
 test_expect_success 'prepare reference tree' '
 	mkdir path0 path1 &&
-	cp "$TEST_DIRECTORY"/../COPYING path0/COPYING &&
+	COPYING_test_data >path0/COPYING &&
 	git add path0/COPYING &&
 	git commit -m add -a
 '
@@ -107,7 +108,7 @@
 '
 
 test_expect_success 'adding another file' '
-	cp "$TEST_DIRECTORY"/../README.md path0/README &&
+	COPYING_test_data | tr A-Za-z N-ZA-Mn-za-m >path0/README &&
 	git add path0/README &&
 	git commit -m add2 -a
 '
diff --git a/t/t7002-mv-sparse-checkout.sh b/t/t7002-mv-sparse-checkout.sh
new file mode 100755
index 0000000..1d3d2ac
--- /dev/null
+++ b/t/t7002-mv-sparse-checkout.sh
@@ -0,0 +1,209 @@
+#!/bin/sh
+
+test_description='git mv in sparse working trees'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' "
+	mkdir -p sub/dir sub/dir2 &&
+	touch a b c sub/d sub/dir/e sub/dir2/e &&
+	git add -A &&
+	git commit -m files &&
+
+	cat >sparse_error_header <<-EOF &&
+	The following paths and/or pathspecs matched paths that exist
+	outside of your sparse-checkout definition, so will not be
+	updated in the index:
+	EOF
+
+	cat >sparse_hint <<-EOF
+	hint: If you intend to update such entries, try one of the following:
+	hint: * Use the --sparse option.
+	hint: * Disable or modify the sparsity rules.
+	hint: Disable this message with \"git config advice.updateSparsePath false\"
+	EOF
+"
+
+test_expect_success 'mv refuses to move sparse-to-sparse' '
+	test_when_finished rm -f e &&
+	git reset --hard &&
+	git sparse-checkout set a &&
+	touch b &&
+	test_must_fail git mv b e 2>stderr &&
+	cat sparse_error_header >expect &&
+	echo b >>expect &&
+	echo e >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr &&
+	git mv --sparse b e 2>stderr &&
+	test_must_be_empty stderr
+'
+
+test_expect_success 'mv refuses to move sparse-to-sparse, ignores failure' '
+	test_when_finished rm -f b c e &&
+	git reset --hard &&
+	git sparse-checkout set a &&
+
+	# tracked-to-untracked
+	touch b &&
+	git mv -k b e 2>stderr &&
+	test_path_exists b &&
+	test_path_is_missing e &&
+	cat sparse_error_header >expect &&
+	echo b >>expect &&
+	echo e >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr &&
+
+	git mv --sparse b e 2>stderr &&
+	test_must_be_empty stderr &&
+	test_path_is_missing b &&
+	test_path_exists e &&
+
+	# tracked-to-tracked
+	git reset --hard &&
+	touch b &&
+	git mv -k b c 2>stderr &&
+	test_path_exists b &&
+	test_path_is_missing c &&
+	cat sparse_error_header >expect &&
+	echo b >>expect &&
+	echo c >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr &&
+
+	git mv --sparse b c 2>stderr &&
+	test_must_be_empty stderr &&
+	test_path_is_missing b &&
+	test_path_exists c
+'
+
+test_expect_success 'mv refuses to move non-sparse-to-sparse' '
+	test_when_finished rm -f b c e &&
+	git reset --hard &&
+	git sparse-checkout set a &&
+
+	# tracked-to-untracked
+	test_must_fail git mv a e 2>stderr &&
+	test_path_exists a &&
+	test_path_is_missing e &&
+	cat sparse_error_header >expect &&
+	echo e >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr &&
+	git mv --sparse a e 2>stderr &&
+	test_must_be_empty stderr &&
+	test_path_is_missing a &&
+	test_path_exists e &&
+
+	# tracked-to-tracked
+	rm e &&
+	git reset --hard &&
+	test_must_fail git mv a c 2>stderr &&
+	test_path_exists a &&
+	test_path_is_missing c &&
+	cat sparse_error_header >expect &&
+	echo c >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr &&
+	git mv --sparse a c 2>stderr &&
+	test_must_be_empty stderr &&
+	test_path_is_missing a &&
+	test_path_exists c
+'
+
+test_expect_success 'mv refuses to move sparse-to-non-sparse' '
+	test_when_finished rm -f b c e &&
+	git reset --hard &&
+	git sparse-checkout set a e &&
+
+	# tracked-to-untracked
+	touch b &&
+	test_must_fail git mv b e 2>stderr &&
+	cat sparse_error_header >expect &&
+	echo b >>expect &&
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr &&
+	git mv --sparse b e 2>stderr &&
+	test_must_be_empty stderr
+'
+
+test_expect_success 'recursive mv refuses to move (possible) sparse' '
+	test_when_finished rm -rf b c e sub2 &&
+	git reset --hard &&
+	# Without cone mode, "sub" and "sub2" do not match
+	git sparse-checkout set sub/dir sub2/dir &&
+
+	# Add contained contents to ensure we avoid non-existence errors
+	mkdir sub/dir2 &&
+	touch sub/d sub/dir2/e &&
+
+	test_must_fail git mv sub sub2 2>stderr &&
+	cat sparse_error_header >expect &&
+	cat >>expect <<-\EOF &&
+	sub/d
+	sub2/d
+	sub/dir2/e
+	sub2/dir2/e
+	EOF
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr &&
+	git mv --sparse sub sub2 2>stderr &&
+	test_must_be_empty stderr &&
+	git commit -m "moved sub to sub2" &&
+	git rev-parse HEAD~1:sub >expect &&
+	git rev-parse HEAD:sub2 >actual &&
+	test_cmp expect actual &&
+	git reset --hard HEAD~1
+'
+
+test_expect_success 'recursive mv refuses to move sparse' '
+	git reset --hard &&
+	# Use cone mode so "sub/" matches the sparse-checkout patterns
+	git sparse-checkout init --cone &&
+	git sparse-checkout set sub/dir sub2/dir &&
+
+	# Add contained contents to ensure we avoid non-existence errors
+	mkdir sub/dir2 &&
+	touch sub/dir2/e &&
+
+	test_must_fail git mv sub sub2 2>stderr &&
+	cat sparse_error_header >expect &&
+	cat >>expect <<-\EOF &&
+	sub/dir2/e
+	sub2/dir2/e
+	EOF
+	cat sparse_hint >>expect &&
+	test_cmp expect stderr &&
+	git mv --sparse sub sub2 2>stderr &&
+	test_must_be_empty stderr &&
+	git commit -m "moved sub to sub2" &&
+	git rev-parse HEAD~1:sub >expect &&
+	git rev-parse HEAD:sub2 >actual &&
+	test_cmp expect actual &&
+	git reset --hard HEAD~1
+'
+
+test_expect_success 'can move files to non-sparse dir' '
+	git reset --hard &&
+	git sparse-checkout init --no-cone &&
+	git sparse-checkout set a b c w !/x y/ &&
+	mkdir -p w x/y &&
+
+	git mv a w/new-a 2>stderr &&
+	git mv b x/y/new-b 2>stderr &&
+	test_must_be_empty stderr
+'
+
+test_expect_success 'refuse to move file to non-skip-worktree sparse path' '
+	git reset --hard &&
+	git sparse-checkout init --no-cone &&
+	git sparse-checkout set a !/x y/ !x/y/z &&
+	mkdir -p x/y/z &&
+
+	test_must_fail git mv a x/y/z/new-a 2>stderr &&
+	echo x/y/z/new-a | cat sparse_error_header - sparse_hint >expect &&
+	test_cmp expect stderr
+'
+
+test_done
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index 2f72c5c..082be85 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -1998,6 +1998,10 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'git tag -l with --format="%(rest)" must fail' '
+	test_must_fail git tag -l --format="%(rest)" "v1*"
+'
+
 test_expect_success "set up color tests" '
 	echo "<RED>v1.0<RESET>" >expect.color &&
 	echo "v1.0" >expect.bare &&
diff --git a/t/t7030-verify-tag.sh b/t/t7030-verify-tag.sh
index 3cefde9..10faa64 100755
--- a/t/t7030-verify-tag.sh
+++ b/t/t7030-verify-tag.sh
@@ -194,6 +194,10 @@
 	test_cmp expect actual
 '
 
+test_expect_success GPG 'verifying tag with --format="%(rest)" must fail' '
+	test_must_fail git verify-tag --format="%(rest)" "fourth-signed"
+'
+
 test_expect_success GPG 'verifying a forged tag with --format should fail silently' '
 	test_must_fail git verify-tag --format="tagname : %(tag)" $(cat forged1.tag) >actual-forged &&
 	test_must_be_empty actual-forged
diff --git a/t/t7031-verify-tag-signed-ssh.sh b/t/t7031-verify-tag-signed-ssh.sh
new file mode 100755
index 0000000..06c9dd6
--- /dev/null
+++ b/t/t7031-verify-tag-signed-ssh.sh
@@ -0,0 +1,161 @@
+#!/bin/sh
+
+test_description='signed tag tests'
+GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
+export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+
+. ./test-lib.sh
+. "$TEST_DIRECTORY/lib-gpg.sh"
+
+test_expect_success GPGSSH 'create signed tags ssh' '
+	test_when_finished "test_unconfig commit.gpgsign" &&
+	test_config gpg.format ssh &&
+	test_config user.signingkey "${GPGSSH_KEY_PRIMARY}" &&
+
+	echo 1 >file && git add file &&
+	test_tick && git commit -m initial &&
+	git tag -s -m initial initial &&
+	git branch side &&
+
+	echo 2 >file && test_tick && git commit -a -m second &&
+	git tag -s -m second second &&
+
+	git checkout side &&
+	echo 3 >elif && git add elif &&
+	test_tick && git commit -m "third on side" &&
+
+	git checkout main &&
+	test_tick && git merge -S side &&
+	git tag -s -m merge merge &&
+
+	echo 4 >file && test_tick && git commit -a -S -m "fourth unsigned" &&
+	git tag -a -m fourth-unsigned fourth-unsigned &&
+
+	test_tick && git commit --amend -S -m "fourth signed" &&
+	git tag -s -m fourth fourth-signed &&
+
+	echo 5 >file && test_tick && git commit -a -m "fifth" &&
+	git tag fifth-unsigned &&
+
+	git config commit.gpgsign true &&
+	echo 6 >file && test_tick && git commit -a -m "sixth" &&
+	git tag -a -m sixth sixth-unsigned &&
+
+	test_tick && git rebase -f HEAD^^ && git tag -s -m 6th sixth-signed HEAD^ &&
+	git tag -m seventh -s seventh-signed &&
+
+	echo 8 >file && test_tick && git commit -a -m eighth &&
+	git tag -u"${GPGSSH_KEY_UNTRUSTED}" -m eighth eighth-signed-alt
+'
+
+test_expect_success GPGSSH 'verify and show ssh signatures' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	(
+		for tag in initial second merge fourth-signed sixth-signed seventh-signed
+		do
+			git verify-tag $tag 2>actual &&
+			grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			echo $tag OK || exit 1
+		done
+	) &&
+	(
+		for tag in fourth-unsigned fifth-unsigned sixth-unsigned
+		do
+			test_must_fail git verify-tag $tag 2>actual &&
+			! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			echo $tag OK || exit 1
+		done
+	) &&
+	(
+		for tag in eighth-signed-alt
+		do
+			test_must_fail git verify-tag $tag 2>actual &&
+			grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			grep "${GPGSSH_KEY_NOT_TRUSTED}" actual &&
+			echo $tag OK || exit 1
+		done
+	)
+'
+
+test_expect_success GPGSSH 'detect fudged ssh signature' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git cat-file tag seventh-signed >raw &&
+	sed -e "/^tag / s/seventh/7th forged/" raw >forged1 &&
+	git hash-object -w -t tag forged1 >forged1.tag &&
+	test_must_fail git verify-tag $(cat forged1.tag) 2>actual1 &&
+	grep "${GPGSSH_BAD_SIGNATURE}" actual1 &&
+	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual1 &&
+	! grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual1
+'
+
+test_expect_success GPGSSH 'verify ssh signatures with --raw' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	(
+		for tag in initial second merge fourth-signed sixth-signed seventh-signed
+		do
+			git verify-tag --raw $tag 2>actual &&
+			grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			echo $tag OK || exit 1
+		done
+	) &&
+	(
+		for tag in fourth-unsigned fifth-unsigned sixth-unsigned
+		do
+			test_must_fail git verify-tag --raw $tag 2>actual &&
+			! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			echo $tag OK || exit 1
+		done
+	) &&
+	(
+		for tag in eighth-signed-alt
+		do
+			test_must_fail git verify-tag --raw $tag 2>actual &&
+			grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			echo $tag OK || exit 1
+		done
+	)
+'
+
+test_expect_success GPGSSH 'verify signatures with --raw ssh' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git verify-tag --raw sixth-signed 2>actual &&
+	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+	! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+	echo sixth-signed OK
+'
+
+test_expect_success GPGSSH 'verify multiple tags ssh' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	tags="seventh-signed sixth-signed" &&
+	for i in $tags
+	do
+		git verify-tag -v --raw $i || return 1
+	done >expect.stdout 2>expect.stderr.1 &&
+	grep "^${GPGSSH_GOOD_SIGNATURE_TRUSTED}" <expect.stderr.1 >expect.stderr &&
+	git verify-tag -v --raw $tags >actual.stdout 2>actual.stderr.1 &&
+	grep "^${GPGSSH_GOOD_SIGNATURE_TRUSTED}" <actual.stderr.1 >actual.stderr &&
+	test_cmp expect.stdout actual.stdout &&
+	test_cmp expect.stderr actual.stderr
+'
+
+test_expect_success GPGSSH 'verifying tag with --format - ssh' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	cat >expect <<-\EOF &&
+	tagname : fourth-signed
+	EOF
+	git verify-tag --format="tagname : %(tag)" "fourth-signed" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success GPGSSH 'verifying a forged tag with --format should fail silently - ssh' '
+	test_must_fail git verify-tag --format="tagname : %(tag)" $(cat forged1.tag) >actual-forged &&
+	test_must_be_empty actual-forged
+'
+
+test_done
diff --git a/t/t7064-wtstatus-pv2.sh b/t/t7064-wtstatus-pv2.sh
index 4613882..eeb0534 100755
--- a/t/t7064-wtstatus-pv2.sh
+++ b/t/t7064-wtstatus-pv2.sh
@@ -373,10 +373,7 @@
 
 		## Test upstream-gone case. Fake this by pointing
 		## origin/initial-branch at a non-existing commit.
-		OLD=$(git rev-parse origin/initial-branch) &&
-		NEW=$ZERO_OID &&
-		mv .git/packed-refs .git/old-packed-refs &&
-		sed "s/$OLD/$NEW/g" <.git/old-packed-refs >.git/packed-refs &&
+		git update-ref -d refs/remotes/origin/initial-branch &&
 
 		HUF=$(git rev-parse HEAD) &&
 
diff --git a/t/t7101-reset-empty-subdirs.sh b/t/t7101-reset-empty-subdirs.sh
index bfce05a..5530651 100755
--- a/t/t7101-reset-empty-subdirs.sh
+++ b/t/t7101-reset-empty-subdirs.sh
@@ -5,10 +5,11 @@
 
 test_description='git reset should cull empty subdirs'
 . ./test-lib.sh
+. "$TEST_DIRECTORY"/lib-diff-data.sh
 
 test_expect_success 'creating initial files' '
      mkdir path0 &&
-     cp "$TEST_DIRECTORY"/../COPYING path0/COPYING &&
+     COPYING_test_data >path0/COPYING &&
      git add path0/COPYING &&
      git commit -m add -a
 '
@@ -16,10 +17,10 @@
 test_expect_success 'creating second files' '
      mkdir path1 &&
      mkdir path1/path2 &&
-     cp "$TEST_DIRECTORY"/../COPYING path1/path2/COPYING &&
-     cp "$TEST_DIRECTORY"/../COPYING path1/COPYING &&
-     cp "$TEST_DIRECTORY"/../COPYING COPYING &&
-     cp "$TEST_DIRECTORY"/../COPYING path0/COPYING-TOO &&
+     COPYING_test_data >path1/path2/COPYING &&
+     COPYING_test_data >path1/COPYING &&
+     COPYING_test_data >COPYING &&
+     COPYING_test_data >path0/COPYING-TOO &&
      git add path1/path2/COPYING &&
      git add path1/COPYING &&
      git add COPYING &&
diff --git a/t/t7104-reset-hard.sh b/t/t7104-reset-hard.sh
index 7948ec3..cf9697e 100755
--- a/t/t7104-reset-hard.sh
+++ b/t/t7104-reset-hard.sh
@@ -2,6 +2,7 @@
 
 test_description='reset --hard unmerged'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success setup '
diff --git a/t/t7112-reset-submodule.sh b/t/t7112-reset-submodule.sh
index 19830d9..a3e2413 100755
--- a/t/t7112-reset-submodule.sh
+++ b/t/t7112-reset-submodule.sh
@@ -6,7 +6,6 @@
 . "$TEST_DIRECTORY"/lib-submodule-update.sh
 
 KNOWN_FAILURE_DIRECTORY_SUBMODULE_CONFLICTS=1
-KNOWN_FAILURE_SUBMODULE_OVERWRITE_IGNORED_UNTRACKED=1
 
 test_submodule_switch_recursing_with_args "reset --keep"
 
diff --git a/t/t7201-co.sh b/t/t7201-co.sh
index 7f6e23a..b7ba1c3 100755
--- a/t/t7201-co.sh
+++ b/t/t7201-co.sh
@@ -585,6 +585,7 @@
 '
 
 test_expect_success 'failing checkout -b should not break working tree' '
+	git clean -fd &&  # Remove untracked files in the way
 	git reset --hard main &&
 	git symbolic-ref HEAD refs/heads/main &&
 	test_must_fail git checkout -b renamer side^ &&
diff --git a/t/t7418-submodule-sparse-gitmodules.sh b/t/t7418-submodule-sparse-gitmodules.sh
index 3f7f2718..f87e524 100755
--- a/t/t7418-submodule-sparse-gitmodules.sh
+++ b/t/t7418-submodule-sparse-gitmodules.sh
@@ -12,6 +12,9 @@
 also by committing .gitmodules and then just removing it from the filesystem.
 '
 
+GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB=1
+export GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB
+
 . ./test-lib.sh
 
 test_expect_success 'sparse checkout setup which hides .gitmodules' '
diff --git a/t/t7505-prepare-commit-msg-hook.sh b/t/t7505-prepare-commit-msg-hook.sh
index 7a8194c..2a07c70 100755
--- a/t/t7505-prepare-commit-msg-hook.sh
+++ b/t/t7505-prepare-commit-msg-hook.sh
@@ -250,7 +250,6 @@
 }
 
 test_rebase success
-test_have_prereq !REBASE_P || test_rebase success -p
 
 test_expect_success 'with hook (cherry-pick)' '
 	test_when_finished "git checkout -f main" &&
diff --git a/t/t7510-signed-commit.sh b/t/t7510-signed-commit.sh
index 8df5a74..d65a017 100755
--- a/t/t7510-signed-commit.sh
+++ b/t/t7510-signed-commit.sh
@@ -71,7 +71,25 @@
 	git tag eleventh-signed $(cat oid) &&
 	echo 12 | git commit-tree --gpg-sign=B7227189 HEAD^{tree} >oid &&
 	test_line_count = 1 oid &&
-	git tag twelfth-signed-alt $(cat oid)
+	git tag twelfth-signed-alt $(cat oid) &&
+
+	cat >keydetails <<-\EOF &&
+	Key-Type: RSA
+	Key-Length: 2048
+	Subkey-Type: RSA
+	Subkey-Length: 2048
+	Name-Real: Unknown User
+	Name-Email: unknown@git.com
+	Expire-Date: 0
+	%no-ask-passphrase
+	%no-protection
+	EOF
+	gpg --batch --gen-key keydetails &&
+	echo 13 >file && git commit -a -S"unknown@git.com" -m thirteenth &&
+	git tag thirteenth-signed &&
+	DELETE_FINGERPRINT=$(gpg -K --with-colons --fingerprint --batch unknown@git.com | grep "^fpr" | head -n 1 | awk -F ":" "{print \$10;}") &&
+	gpg --batch --yes --delete-secret-keys $DELETE_FINGERPRINT &&
+	gpg --batch --yes --delete-keys unknown@git.com
 '
 
 test_expect_success GPG 'verify and show signatures' '
@@ -110,6 +128,13 @@
 	)
 '
 
+test_expect_success GPG 'verify-commit exits failure on unknown signature' '
+	test_must_fail git verify-commit thirteenth-signed 2>actual &&
+	! grep "Good signature from" actual &&
+	! grep "BAD signature from" actual &&
+	grep -q -F -e "No public key" -e "public key not found" actual
+'
+
 test_expect_success GPG 'verify-commit exits success on untrusted signature' '
 	git verify-commit eighth-signed-alt 2>actual &&
 	grep "Good signature from" actual &&
@@ -338,6 +363,8 @@
 '
 
 
+# NEEDSWORK: This test relies on the test_tick commit/author dates from the first
+# 'create signed commits' test even though it creates its own
 test_expect_success GPG 'verify-commit verifies multiply signed commits' '
 	git init multiply-signed &&
 	cd multiply-signed &&
diff --git a/t/t7517-per-repo-email.sh b/t/t7517-per-repo-email.sh
index 405420a..163ae80 100755
--- a/t/t7517-per-repo-email.sh
+++ b/t/t7517-per-repo-email.sh
@@ -75,19 +75,6 @@
 	git rebase -i HEAD^
 '
 
-test_expect_success REBASE_P \
-	'fast-forward rebase does not care about ident (preserve)' '
-	git checkout -B tmp side-without-commit &&
-	git rebase -p main
-'
-
-test_expect_success REBASE_P \
-	'non-fast-forward rebase refuses to write commits (preserve)' '
-	test_when_finished "git rebase --abort || true" &&
-	git checkout -B tmp side-with-commit &&
-	test_must_fail git rebase -p main
-'
-
 test_expect_success 'author.name overrides user.name' '
 	test_config user.name user &&
 	test_config user.email user@example.com &&
diff --git a/t/t7518-ident-corner-cases.sh b/t/t7518-ident-corner-cases.sh
index 905957b..fffdb6f 100755
--- a/t/t7518-ident-corner-cases.sh
+++ b/t/t7518-ident-corner-cases.sh
@@ -1,6 +1,8 @@
 #!/bin/sh
 
 test_description='corner cases in ident strings'
+
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 # confirm that we do not segfault _and_ that we do not say "(null)", as
diff --git a/t/t7519-status-fsmonitor.sh b/t/t7519-status-fsmonitor.sh
index deea88d..f488d93 100755
--- a/t/t7519-status-fsmonitor.sh
+++ b/t/t7519-status-fsmonitor.sh
@@ -389,47 +389,55 @@
 # If "!" is supplied, then we verify that we do not call ensure_full_index
 # during a call to 'git status'. Otherwise, we verify that we _do_ call it.
 check_sparse_index_behavior () {
-	git status --porcelain=v2 >expect &&
-	git sparse-checkout init --cone --sparse-index &&
-	git sparse-checkout set dir1 dir2 &&
+	git -C full status --porcelain=v2 >expect &&
 	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
-		git status --porcelain=v2 >actual &&
+		git -C sparse status --porcelain=v2 >actual &&
 	test_region $1 index ensure_full_index trace2.txt &&
 	test_region fsm_hook query trace2.txt &&
 	test_cmp expect actual &&
-	rm trace2.txt &&
-	git sparse-checkout disable
+	rm trace2.txt
 }
 
 test_expect_success 'status succeeds with sparse index' '
-	git reset --hard &&
+	(
+		sane_unset GIT_TEST_SPLIT_INDEX &&
 
-	test_config core.fsmonitor "$TEST_DIRECTORY/t7519/fsmonitor-all" &&
-	check_sparse_index_behavior ! &&
+		git clone . full &&
+		git clone --sparse . sparse &&
+		git -C sparse sparse-checkout init --cone --sparse-index &&
+		git -C sparse sparse-checkout set dir1 dir2 &&
 
-	write_script .git/hooks/fsmonitor-test<<-\EOF &&
-		printf "last_update_token\0"
-	EOF
-	git config core.fsmonitor .git/hooks/fsmonitor-test &&
-	check_sparse_index_behavior ! &&
+		write_script .git/hooks/fsmonitor-test <<-\EOF &&
+			printf "last_update_token\0"
+		EOF
+		git -C full config core.fsmonitor ../.git/hooks/fsmonitor-test &&
+		git -C sparse config core.fsmonitor ../.git/hooks/fsmonitor-test &&
+		check_sparse_index_behavior ! &&
 
-	write_script .git/hooks/fsmonitor-test<<-\EOF &&
-		printf "last_update_token\0"
-		printf "dir1/modified\0"
-	EOF
-	check_sparse_index_behavior ! &&
+		write_script .git/hooks/fsmonitor-test <<-\EOF &&
+			printf "last_update_token\0"
+			printf "dir1/modified\0"
+		EOF
+		check_sparse_index_behavior ! &&
 
-	cp -r dir1 dir1a &&
-	git add dir1a &&
-	git commit -m "add dir1a" &&
+		git -C sparse sparse-checkout add dir1a &&
 
-	# This one modifies outside the sparse-checkout definition
-	# and hence we expect to expand the sparse-index.
-	write_script .git/hooks/fsmonitor-test<<-\EOF &&
-		printf "last_update_token\0"
-		printf "dir1a/modified\0"
-	EOF
-	check_sparse_index_behavior
+		for repo in full sparse
+		do
+			cp -r $repo/dir1 $repo/dir1a &&
+			git -C $repo add dir1a &&
+			git -C $repo commit -m "add dir1a" || return 1
+		done &&
+		git -C sparse sparse-checkout set dir1 dir2 &&
+
+		# This one modifies outside the sparse-checkout definition
+		# and hence we expect to expand the sparse-index.
+		write_script .git/hooks/fsmonitor-test <<-\EOF &&
+			printf "last_update_token\0"
+			printf "dir1a/modified\0"
+		EOF
+		check_sparse_index_behavior
+	)
 '
 
 test_done
diff --git a/t/t7528-signed-commit-ssh.sh b/t/t7528-signed-commit-ssh.sh
new file mode 100755
index 0000000..badf3ed
--- /dev/null
+++ b/t/t7528-signed-commit-ssh.sh
@@ -0,0 +1,398 @@
+#!/bin/sh
+
+test_description='ssh signed commit tests'
+GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
+export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
+
+. ./test-lib.sh
+GNUPGHOME_NOT_USED=$GNUPGHOME
+. "$TEST_DIRECTORY/lib-gpg.sh"
+
+test_expect_success GPGSSH 'create signed commits' '
+	test_oid_cache <<-\EOF &&
+	header sha1:gpgsig
+	header sha256:gpgsig-sha256
+	EOF
+
+	test_when_finished "test_unconfig commit.gpgsign" &&
+	test_config gpg.format ssh &&
+	test_config user.signingkey "${GPGSSH_KEY_PRIMARY}" &&
+
+	echo 1 >file && git add file &&
+	test_tick && git commit -S -m initial &&
+	git tag initial &&
+	git branch side &&
+
+	echo 2 >file && test_tick && git commit -a -S -m second &&
+	git tag second &&
+
+	git checkout side &&
+	echo 3 >elif && git add elif &&
+	test_tick && git commit -m "third on side" &&
+
+	git checkout main &&
+	test_tick && git merge -S side &&
+	git tag merge &&
+
+	echo 4 >file && test_tick && git commit -a -m "fourth unsigned" &&
+	git tag fourth-unsigned &&
+
+	test_tick && git commit --amend -S -m "fourth signed" &&
+	git tag fourth-signed &&
+
+	git config commit.gpgsign true &&
+	echo 5 >file && test_tick && git commit -a -m "fifth signed" &&
+	git tag fifth-signed &&
+
+	git config commit.gpgsign false &&
+	echo 6 >file && test_tick && git commit -a -m "sixth" &&
+	git tag sixth-unsigned &&
+
+	git config commit.gpgsign true &&
+	echo 7 >file && test_tick && git commit -a -m "seventh" --no-gpg-sign &&
+	git tag seventh-unsigned &&
+
+	test_tick && git rebase -f HEAD^^ && git tag sixth-signed HEAD^ &&
+	git tag seventh-signed &&
+
+	echo 8 >file && test_tick && git commit -a -m eighth -S"${GPGSSH_KEY_UNTRUSTED}" &&
+	git tag eighth-signed-alt &&
+
+	# commit.gpgsign is still on but this must not be signed
+	echo 9 | git commit-tree HEAD^{tree} >oid &&
+	test_line_count = 1 oid &&
+	git tag ninth-unsigned $(cat oid) &&
+	# explicit -S of course must sign.
+	echo 10 | git commit-tree -S HEAD^{tree} >oid &&
+	test_line_count = 1 oid &&
+	git tag tenth-signed $(cat oid) &&
+
+	# --gpg-sign[=<key-id>] must sign.
+	echo 11 | git commit-tree --gpg-sign HEAD^{tree} >oid &&
+	test_line_count = 1 oid &&
+	git tag eleventh-signed $(cat oid) &&
+	echo 12 | git commit-tree --gpg-sign="${GPGSSH_KEY_UNTRUSTED}" HEAD^{tree} >oid &&
+	test_line_count = 1 oid &&
+	git tag twelfth-signed-alt $(cat oid)
+'
+
+test_expect_success GPGSSH 'verify and show signatures' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	test_config gpg.mintrustlevel UNDEFINED &&
+	(
+		for commit in initial second merge fourth-signed \
+			fifth-signed sixth-signed seventh-signed tenth-signed \
+			eleventh-signed
+		do
+			git verify-commit $commit &&
+			git show --pretty=short --show-signature $commit >actual &&
+			grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			echo $commit OK || exit 1
+		done
+	) &&
+	(
+		for commit in merge^2 fourth-unsigned sixth-unsigned \
+			seventh-unsigned ninth-unsigned
+		do
+			test_must_fail git verify-commit $commit &&
+			git show --pretty=short --show-signature $commit >actual &&
+			! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			echo $commit OK || exit 1
+		done
+	) &&
+	(
+		for commit in eighth-signed-alt twelfth-signed-alt
+		do
+			git show --pretty=short --show-signature $commit >actual &&
+			grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			grep "${GPGSSH_KEY_NOT_TRUSTED}" actual &&
+			echo $commit OK || exit 1
+		done
+	)
+'
+
+test_expect_success GPGSSH 'verify-commit exits failure on untrusted signature' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	test_must_fail git verify-commit eighth-signed-alt 2>actual &&
+	grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+	! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+	grep "${GPGSSH_KEY_NOT_TRUSTED}" actual
+'
+
+test_expect_success GPGSSH 'verify-commit exits success with matching minTrustLevel' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	test_config gpg.minTrustLevel fully &&
+	git verify-commit sixth-signed
+'
+
+test_expect_success GPGSSH 'verify-commit exits success with low minTrustLevel' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	test_config gpg.minTrustLevel marginal &&
+	git verify-commit sixth-signed
+'
+
+test_expect_success GPGSSH 'verify-commit exits failure with high minTrustLevel' '
+	test_config gpg.minTrustLevel ultimate &&
+	test_must_fail git verify-commit eighth-signed-alt
+'
+
+test_expect_success GPGSSH 'verify signatures with --raw' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	(
+		for commit in initial second merge fourth-signed fifth-signed sixth-signed seventh-signed
+		do
+			git verify-commit --raw $commit 2>actual &&
+			grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			echo $commit OK || exit 1
+		done
+	) &&
+	(
+		for commit in merge^2 fourth-unsigned sixth-unsigned seventh-unsigned
+		do
+			test_must_fail git verify-commit --raw $commit 2>actual &&
+			! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			echo $commit OK || exit 1
+		done
+	) &&
+	(
+		for commit in eighth-signed-alt
+		do
+			test_must_fail git verify-commit --raw $commit 2>actual &&
+			grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual &&
+			! grep "${GPGSSH_BAD_SIGNATURE}" actual &&
+			echo $commit OK || exit 1
+		done
+	)
+'
+
+test_expect_success GPGSSH 'proper header is used for hash algorithm' '
+	git cat-file commit fourth-signed >output &&
+	grep "^$(test_oid header) -----BEGIN SSH SIGNATURE-----" output
+'
+
+test_expect_success GPGSSH 'show signed commit with signature' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git show -s initial >commit &&
+	git show -s --show-signature initial >show &&
+	git verify-commit -v initial >verify.1 2>verify.2 &&
+	git cat-file commit initial >cat &&
+	grep -v -e "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" -e "Warning: " show >show.commit &&
+	grep -e "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" -e "Warning: " show >show.gpg &&
+	grep -v "^ " cat | grep -v "^gpgsig.* " >cat.commit &&
+	test_cmp show.commit commit &&
+	test_cmp show.gpg verify.2 &&
+	test_cmp cat.commit verify.1
+'
+
+test_expect_success GPGSSH 'detect fudged signature' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git cat-file commit seventh-signed >raw &&
+	sed -e "s/^seventh/7th forged/" raw >forged1 &&
+	git hash-object -w -t commit forged1 >forged1.commit &&
+	test_must_fail git verify-commit $(cat forged1.commit) &&
+	git show --pretty=short --show-signature $(cat forged1.commit) >actual1 &&
+	grep "${GPGSSH_BAD_SIGNATURE}" actual1 &&
+	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual1 &&
+	! grep "${GPGSSH_GOOD_SIGNATURE_UNTRUSTED}" actual1
+'
+
+test_expect_success GPGSSH 'detect fudged signature with NUL' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git cat-file commit seventh-signed >raw &&
+	cat raw >forged2 &&
+	echo Qwik | tr "Q" "\000" >>forged2 &&
+	git hash-object -w -t commit forged2 >forged2.commit &&
+	test_must_fail git verify-commit $(cat forged2.commit) &&
+	git show --pretty=short --show-signature $(cat forged2.commit) >actual2 &&
+	grep "${GPGSSH_BAD_SIGNATURE}" actual2 &&
+	! grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual2
+'
+
+test_expect_success GPGSSH 'amending already signed commit' '
+	test_config gpg.format ssh &&
+	test_config user.signingkey "${GPGSSH_KEY_PRIMARY}" &&
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	git checkout fourth-signed^0 &&
+	git commit --amend -S --no-edit &&
+	git verify-commit HEAD &&
+	git show -s --show-signature HEAD >actual &&
+	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual &&
+	! grep "${GPGSSH_BAD_SIGNATURE}" actual
+'
+
+test_expect_success GPGSSH 'show good signature with custom format' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	FINGERPRINT=$(ssh-keygen -lf "${GPGSSH_KEY_PRIMARY}" | awk "{print \$2;}") &&
+	cat >expect.tmpl <<-\EOF &&
+	G
+	FINGERPRINT
+	principal with number 1
+	FINGERPRINT
+
+	EOF
+	sed "s|FINGERPRINT|$FINGERPRINT|g" expect.tmpl >expect &&
+	git log -1 --format="%G?%n%GK%n%GS%n%GF%n%GP" sixth-signed >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success GPGSSH 'show bad signature with custom format' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	cat >expect <<-\EOF &&
+	B
+
+
+
+
+	EOF
+	git log -1 --format="%G?%n%GK%n%GS%n%GF%n%GP" $(cat forged1.commit) >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success GPGSSH 'show untrusted signature with custom format' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	cat >expect.tmpl <<-\EOF &&
+	U
+	FINGERPRINT
+
+	FINGERPRINT
+
+	EOF
+	git log -1 --format="%G?%n%GK%n%GS%n%GF%n%GP" eighth-signed-alt >actual &&
+	FINGERPRINT=$(ssh-keygen -lf "${GPGSSH_KEY_UNTRUSTED}" | awk "{print \$2;}") &&
+	sed "s|FINGERPRINT|$FINGERPRINT|g" expect.tmpl >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success GPGSSH 'show untrusted signature with undefined trust level' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	cat >expect.tmpl <<-\EOF &&
+	undefined
+	FINGERPRINT
+
+	FINGERPRINT
+
+	EOF
+	git log -1 --format="%GT%n%GK%n%GS%n%GF%n%GP" eighth-signed-alt >actual &&
+	FINGERPRINT=$(ssh-keygen -lf "${GPGSSH_KEY_UNTRUSTED}" | awk "{print \$2;}") &&
+	sed "s|FINGERPRINT|$FINGERPRINT|g" expect.tmpl >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success GPGSSH 'show untrusted signature with ultimate trust level' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	cat >expect.tmpl <<-\EOF &&
+	fully
+	FINGERPRINT
+	principal with number 1
+	FINGERPRINT
+
+	EOF
+	git log -1 --format="%GT%n%GK%n%GS%n%GF%n%GP" sixth-signed >actual &&
+	FINGERPRINT=$(ssh-keygen -lf "${GPGSSH_KEY_PRIMARY}" | awk "{print \$2;}") &&
+	sed "s|FINGERPRINT|$FINGERPRINT|g" expect.tmpl >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success GPGSSH 'show lack of signature with custom format' '
+	cat >expect <<-\EOF &&
+	N
+
+
+
+
+	EOF
+	git log -1 --format="%G?%n%GK%n%GS%n%GF%n%GP" seventh-unsigned >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success GPGSSH 'log.showsignature behaves like --show-signature' '
+	test_config gpg.ssh.allowedSignersFile "${GPGSSH_ALLOWED_SIGNERS}" &&
+	test_config log.showsignature true &&
+	git show initial >actual &&
+	grep "${GPGSSH_GOOD_SIGNATURE_TRUSTED}" actual
+'
+
+test_expect_success GPGSSH 'check config gpg.format values' '
+	test_config gpg.format ssh &&
+	test_config user.signingkey "${GPGSSH_KEY_PRIMARY}" &&
+	test_config gpg.format ssh &&
+	git commit -S --amend -m "success" &&
+	test_config gpg.format OpEnPgP &&
+	test_must_fail git commit -S --amend -m "fail"
+'
+
+test_expect_failure GPGSSH 'detect fudged commit with double signature (TODO)' '
+	sed -e "/gpgsig/,/END PGP/d" forged1 >double-base &&
+	sed -n -e "/gpgsig/,/END PGP/p" forged1 | \
+		sed -e "s/^$(test_oid header)//;s/^ //" | gpg --dearmor >double-sig1.sig &&
+	gpg -o double-sig2.sig -u 29472784 --detach-sign double-base &&
+	cat double-sig1.sig double-sig2.sig | gpg --enarmor >double-combined.asc &&
+	sed -e "s/^\(-.*\)ARMORED FILE/\1SIGNATURE/;1s/^/$(test_oid header) /;2,\$s/^/ /" \
+		double-combined.asc > double-gpgsig &&
+	sed -e "/committer/r double-gpgsig" double-base >double-commit &&
+	git hash-object -w -t commit double-commit >double-commit.commit &&
+	test_must_fail git verify-commit $(cat double-commit.commit) &&
+	git show --pretty=short --show-signature $(cat double-commit.commit) >double-actual &&
+	grep "BAD signature from" double-actual &&
+	grep "Good signature from" double-actual
+'
+
+test_expect_failure GPGSSH 'show double signature with custom format (TODO)' '
+	cat >expect <<-\EOF &&
+	E
+
+
+
+
+	EOF
+	git log -1 --format="%G?%n%GK%n%GS%n%GF%n%GP" $(cat double-commit.commit) >actual &&
+	test_cmp expect actual
+'
+
+
+test_expect_failure GPGSSH 'verify-commit verifies multiply signed commits (TODO)' '
+	git init multiply-signed &&
+	cd multiply-signed &&
+	test_commit first &&
+	echo 1 >second &&
+	git add second &&
+	tree=$(git write-tree) &&
+	parent=$(git rev-parse HEAD^{commit}) &&
+	git commit --gpg-sign -m second &&
+	git cat-file commit HEAD &&
+	# Avoid trailing whitespace.
+	sed -e "s/^Q//" -e "s/^Z/ /" >commit <<-EOF &&
+	Qtree $tree
+	Qparent $parent
+	Qauthor A U Thor <author@example.com> 1112912653 -0700
+	Qcommitter C O Mitter <committer@example.com> 1112912653 -0700
+	Qgpgsig -----BEGIN PGP SIGNATURE-----
+	QZ
+	Q iHQEABECADQWIQRz11h0S+chaY7FTocTtvUezd5DDQUCX/uBDRYcY29tbWl0dGVy
+	Q QGV4YW1wbGUuY29tAAoJEBO29R7N3kMNd+8AoK1I8mhLHviPH+q2I5fIVgPsEtYC
+	Q AKCTqBh+VabJceXcGIZuF0Ry+udbBQ==
+	Q =tQ0N
+	Q -----END PGP SIGNATURE-----
+	Qgpgsig-sha256 -----BEGIN PGP SIGNATURE-----
+	QZ
+	Q iHQEABECADQWIQRz11h0S+chaY7FTocTtvUezd5DDQUCX/uBIBYcY29tbWl0dGVy
+	Q QGV4YW1wbGUuY29tAAoJEBO29R7N3kMN/NEAn0XO9RYSBj2dFyozi0JKSbssYMtO
+	Q AJwKCQ1BQOtuwz//IjU8TiS+6S4iUw==
+	Q =pIwP
+	Q -----END PGP SIGNATURE-----
+	Q
+	Qsecond
+	EOF
+	head=$(git hash-object -t commit -w commit) &&
+	git reset --hard $head &&
+	git verify-commit $head 2>actual &&
+	grep "Good signature from" actual &&
+	! grep "BAD signature from" actual
+'
+
+test_done
diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
index 2ef39d3..c773e30 100755
--- a/t/t7600-merge.sh
+++ b/t/t7600-merge.sh
@@ -717,6 +717,7 @@
 	git reset --hard c0 &&
 	git merge-file file file.orig file.5 &&
 	cp file.5 other &&
+	test_when_finished "rm other" &&
 	test_must_fail git merge --autostash c1 2>err &&
 	test_i18ngrep "Applied autostash." err &&
 	test_cmp file.5 file
diff --git a/t/t7604-merge-custom-message.sh b/t/t7604-merge-custom-message.sh
index cd4f960..eca7555 100755
--- a/t/t7604-merge-custom-message.sh
+++ b/t/t7604-merge-custom-message.sh
@@ -4,6 +4,7 @@
 
 Testing merge when using a custom message for the merge commit.'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 create_merge_msgs() {
diff --git a/t/t7700-repack.sh b/t/t7700-repack.sh
index 25b235c..0260ad6 100755
--- a/t/t7700-repack.sh
+++ b/t/t7700-repack.sh
@@ -3,6 +3,8 @@
 test_description='git repack works correctly'
 
 . ./test-lib.sh
+. "${TEST_DIRECTORY}/lib-bitmap.sh"
+. "${TEST_DIRECTORY}/lib-midx.sh"
 
 commit_and_pack () {
 	test_commit "$@" 1>&2 &&
@@ -63,13 +65,14 @@
 
 test_expect_success 'writing bitmaps via command-line can duplicate .keep objects' '
 	# build on $oid, $packid, and .keep state from previous
-	git repack -Adbl &&
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 git repack -Adbl &&
 	test_has_duplicate_object true
 '
 
 test_expect_success 'writing bitmaps via config can duplicate .keep objects' '
 	# build on $oid, $packid, and .keep state from previous
-	git -c repack.writebitmaps=true repack -Adl &&
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
+		git -c repack.writebitmaps=true repack -Adl &&
 	test_has_duplicate_object true
 '
 
@@ -189,7 +192,9 @@
 
 test_expect_success 'bitmaps are created by default in bare repos' '
 	git clone --bare .git bare.git &&
-	git -C bare.git repack -ad &&
+	rm -f bare.git/objects/pack/*.bitmap &&
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
+		git -C bare.git repack -ad &&
 	bitmap=$(ls bare.git/objects/pack/*.bitmap) &&
 	test_path_is_file "$bitmap"
 '
@@ -200,7 +205,8 @@
 '
 
 test_expect_success 'bitmaps can be disabled on bare repos' '
-	git -c repack.writeBitmaps=false -C bare.git repack -ad &&
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
+		git -c repack.writeBitmaps=false -C bare.git repack -ad &&
 	bitmap=$(ls bare.git/objects/pack/*.bitmap || :) &&
 	test -z "$bitmap"
 '
@@ -211,7 +217,8 @@
 	keep=${pack%.pack}.keep &&
 	test_when_finished "rm -f \"\$keep\"" &&
 	>"$keep" &&
-	git -C bare.git repack -ad 2>stderr &&
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
+		git -C bare.git repack -ad 2>stderr &&
 	test_must_be_empty stderr &&
 	find bare.git/objects/pack/ -type f -name "*.bitmap" >actual &&
 	test_must_be_empty actual
@@ -222,10 +229,147 @@
 	blob=$(test-tool genrandom big $((1024*1024)) |
 	       git -C bare.git hash-object -w --stdin) &&
 	git -C bare.git update-ref refs/tags/big $blob &&
-	git -C bare.git repack -ad 2>stderr &&
+	GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP=0 \
+		git -C bare.git repack -ad 2>stderr &&
 	test_must_be_empty stderr &&
 	find bare.git/objects/pack -type f -name "*.bitmap" >actual &&
 	test_must_be_empty actual
 '
 
+objdir=.git/objects
+midx=$objdir/pack/multi-pack-index
+
+test_expect_success 'setup for --write-midx tests' '
+	git init midx &&
+	(
+		cd midx &&
+		git config core.multiPackIndex true &&
+
+		test_commit base
+	)
+'
+
+test_expect_success '--write-midx unchanged' '
+	(
+		cd midx &&
+		GIT_TEST_MULTI_PACK_INDEX=0 git repack &&
+		test_path_is_missing $midx &&
+		test_path_is_missing $midx-*.bitmap &&
+
+		GIT_TEST_MULTI_PACK_INDEX=0 git repack --write-midx &&
+
+		test_path_is_file $midx &&
+		test_path_is_missing $midx-*.bitmap &&
+		test_midx_consistent $objdir
+	)
+'
+
+test_expect_success '--write-midx with a new pack' '
+	(
+		cd midx &&
+		test_commit loose &&
+
+		GIT_TEST_MULTI_PACK_INDEX=0 git repack --write-midx &&
+
+		test_path_is_file $midx &&
+		test_path_is_missing $midx-*.bitmap &&
+		test_midx_consistent $objdir
+	)
+'
+
+test_expect_success '--write-midx with -b' '
+	(
+		cd midx &&
+		GIT_TEST_MULTI_PACK_INDEX=0 git repack -mb &&
+
+		test_path_is_file $midx &&
+		test_path_is_file $midx-*.bitmap &&
+		test_midx_consistent $objdir
+	)
+'
+
+test_expect_success '--write-midx with -d' '
+	(
+		cd midx &&
+		test_commit repack &&
+
+		GIT_TEST_MULTI_PACK_INDEX=0 git repack -Ad --write-midx &&
+
+		test_path_is_file $midx &&
+		test_path_is_missing $midx-*.bitmap &&
+		test_midx_consistent $objdir
+	)
+'
+
+test_expect_success 'cleans up MIDX when appropriate' '
+	(
+		cd midx &&
+
+		test_commit repack-2 &&
+		GIT_TEST_MULTI_PACK_INDEX=0 git repack -Adb --write-midx &&
+
+		checksum=$(midx_checksum $objdir) &&
+		test_path_is_file $midx &&
+		test_path_is_file $midx-$checksum.bitmap &&
+		test_path_is_file $midx-$checksum.rev &&
+
+		test_commit repack-3 &&
+		GIT_TEST_MULTI_PACK_INDEX=0 git repack -Adb --write-midx &&
+
+		test_path_is_file $midx &&
+		test_path_is_missing $midx-$checksum.bitmap &&
+		test_path_is_missing $midx-$checksum.rev &&
+		test_path_is_file $midx-$(midx_checksum $objdir).bitmap &&
+		test_path_is_file $midx-$(midx_checksum $objdir).rev &&
+
+		test_commit repack-4 &&
+		GIT_TEST_MULTI_PACK_INDEX=0 git repack -Adb &&
+
+		find $objdir/pack -type f -name "multi-pack-index*" >files &&
+		test_must_be_empty files
+	)
+'
+
+test_expect_success '--write-midx with preferred bitmap tips' '
+	git init midx-preferred-tips &&
+	test_when_finished "rm -fr midx-preferred-tips" &&
+	(
+		cd midx-preferred-tips &&
+
+		test_commit_bulk --message="%s" 103 &&
+
+		git log --format="%H" >commits.raw &&
+		sort <commits.raw >commits &&
+
+		git log --format="create refs/tags/%s/%s %H" HEAD >refs &&
+		git update-ref --stdin <refs &&
+
+		git repack --write-midx --write-bitmap-index &&
+		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 &&
+
+		rm -fr $midx-$(midx_checksum $objdir).bitmap &&
+		rm -fr $midx-$(midx_checksum $objdir).rev &&
+		rm -fr $midx &&
+
+		# instead of constructing the snapshot ourselves (c.f., the test
+		# "write a bitmap with --refs-snapshot (preferred tips)" in
+		# t5326), mark the missing commit as preferred by adding it to
+		# the pack.preferBitmapTips configuration.
+		git for-each-ref --format="%(refname:rstrip=1)" \
+			--points-at="$(cat before)" >missing &&
+		git config pack.preferBitmapTips "$(cat missing)" &&
+		git repack --write-midx --write-bitmap-index &&
+
+		test-tool bitmap list-commits | sort >bitmaps &&
+		comm -13 bitmaps commits >after &&
+
+		! test_cmp before after
+	)
+'
+
 test_done
diff --git a/t/t7703-repack-geometric.sh b/t/t7703-repack-geometric.sh
index 5ccaa44..bdbbcbf 100755
--- a/t/t7703-repack-geometric.sh
+++ b/t/t7703-repack-geometric.sh
@@ -15,7 +15,7 @@
 	(
 		cd geometric &&
 
-		git repack --geometric 2 >out &&
+		git repack --write-midx --geometric 2 >out &&
 		test_i18ngrep "Nothing new to pack" out
 	)
 '
@@ -180,4 +180,26 @@
 	)
 '
 
+test_expect_success '--geometric chooses largest MIDX preferred pack' '
+	git init geometric &&
+	test_when_finished "rm -fr geometric" &&
+	(
+		cd geometric &&
+
+		# These packs already form a geometric progression.
+		test_commit_bulk --start=1 1 && # 3 objects
+		test_commit_bulk --start=2 2 && # 6 objects
+		ls $objdir/pack/pack-*.idx >before &&
+		test_commit_bulk --start=4 4 && # 12 objects
+		ls $objdir/pack/pack-*.idx >after &&
+
+		git repack --geometric 2 -dbm &&
+
+		comm -3 before after | xargs -n 1 basename >expect &&
+		test-tool read-midx --preferred-pack $objdir >actual &&
+
+		test_cmp expect actual
+	)
+'
+
 test_done
diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 528e0da..0964562 100755
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -453,6 +453,13 @@
 	grep "^file$" output
 '
 
+run_dir_diff_test 'difftool --dir-diff avoids repeated slashes in TMPDIR' '
+	TMPDIR="${TMPDIR:-/tmp}////" \
+		git difftool --dir-diff $symlinks --extcmd echo branch >output &&
+	grep -v // output >actual &&
+	test_line_count = 1 actual
+'
+
 run_dir_diff_test 'difftool --dir-diff ignores --prompt' '
 	git difftool --dir-diff $symlinks --prompt --extcmd ls branch >output &&
 	grep "^sub$" output &&
diff --git a/t/t7811-grep-open.sh b/t/t7811-grep-open.sh
index a98785d..1dd0714 100755
--- a/t/t7811-grep-open.sh
+++ b/t/t7811-grep-open.sh
@@ -3,6 +3,7 @@
 test_description='git grep --open-files-in-pager
 '
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-pager.sh
 unset PAGER GIT_PAGER
@@ -114,8 +115,8 @@
 	unrelated
 	EOF
 
+	test_when_finished "git reset --hard" &&
 	echo "enum grep_pat_token" >unrelated &&
-	test_when_finished "git checkout HEAD unrelated" &&
 	GIT_PAGER=./less git grep -F -O "enum grep_pat_token" >out &&
 	test_cmp expect actual &&
 	test_must_be_empty out
diff --git a/t/t7813-grep-icase-iso.sh b/t/t7813-grep-icase-iso.sh
index 701e08a..1227885 100755
--- a/t/t7813-grep-icase-iso.sh
+++ b/t/t7813-grep-icase-iso.sh
@@ -2,6 +2,7 @@
 
 test_description='grep icase on non-English locales'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./lib-gettext.sh
 
 test_expect_success GETTEXT_ISO_LOCALE 'setup' '
diff --git a/t/t7814-grep-recurse-submodules.sh b/t/t7814-grep-recurse-submodules.sh
index 828cb3b..058e5d0 100755
--- a/t/t7814-grep-recurse-submodules.sh
+++ b/t/t7814-grep-recurse-submodules.sh
@@ -8,6 +8,9 @@
 
 . ./test-lib.sh
 
+GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB=1
+export GIT_TEST_FATAL_REGISTER_SUBMODULE_ODB
+
 test_expect_success 'setup directory structure and submodule' '
 	echo "(1|2)d(3|4)" >a &&
 	mkdir b &&
@@ -438,4 +441,107 @@
 	test_must_fail git grep --recurse-submodules --cached "A modified line in submodule" >actual 2>&1 &&
 	test_must_be_empty actual
 '
+
+test_expect_failure 'grep --textconv: superproject .gitattributes does not affect submodules' '
+	reset_and_clean &&
+	test_config_global diff.d2x.textconv "sed -e \"s/d/x/\"" &&
+	echo "a diff=d2x" >.gitattributes &&
+
+	cat >expect <<-\EOF &&
+	a:(1|2)x(3|4)
+	EOF
+	git grep --textconv --recurse-submodules x >actual &&
+	test_cmp expect actual
+'
+
+test_expect_failure 'grep --textconv: superproject .gitattributes (from index) does not affect submodules' '
+	reset_and_clean &&
+	test_config_global diff.d2x.textconv "sed -e \"s/d/x/\"" &&
+	echo "a diff=d2x" >.gitattributes &&
+	git add .gitattributes &&
+	rm .gitattributes &&
+
+	cat >expect <<-\EOF &&
+	a:(1|2)x(3|4)
+	EOF
+	git grep --textconv --recurse-submodules x >actual &&
+	test_cmp expect actual
+'
+
+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="$(git rev-parse --git-path info/attributes)" &&
+	test_when_finished "rm -f \"$super_attr\"" &&
+	echo "a diff=d2x" >"$super_attr" &&
+
+	cat >expect <<-\EOF &&
+	a:(1|2)x(3|4)
+	EOF
+	git grep --textconv --recurse-submodules x >actual &&
+	test_cmp expect actual
+'
+
+# Note: what currently prevents this test from passing is not that the
+# .gitattributes file from "./submodule" is being ignored, but that it is being
+# propagated to the nested "./submodule/sub" files.
+#
+test_expect_failure 'grep --textconv correctly reads submodule .gitattributes' '
+	reset_and_clean &&
+	test_config_global diff.d2x.textconv "sed -e \"s/d/x/\"" &&
+	echo "a diff=d2x" >submodule/.gitattributes &&
+
+	cat >expect <<-\EOF &&
+	submodule/a:(1|2)x(3|4)
+	EOF
+	git grep --textconv --recurse-submodules x >actual &&
+	test_cmp expect actual
+'
+
+test_expect_failure 'grep --textconv correctly reads submodule .gitattributes (from index)' '
+	reset_and_clean &&
+	test_config_global diff.d2x.textconv "sed -e \"s/d/x/\"" &&
+	echo "a diff=d2x" >submodule/.gitattributes &&
+	git -C submodule add .gitattributes &&
+	rm submodule/.gitattributes &&
+
+	cat >expect <<-\EOF &&
+	submodule/a:(1|2)x(3|4)
+	EOF
+	git grep --textconv --recurse-submodules x >actual &&
+	test_cmp expect actual
+'
+
+test_expect_failure 'grep --textconv correctly reads submodule .git/info/attributes' '
+	reset_and_clean &&
+	test_config_global diff.d2x.textconv "sed -e \"s/d/x/\"" &&
+
+	submodule_attr="$(git -C submodule rev-parse --path-format=absolute --git-path info/attributes)" &&
+	test_when_finished "rm -f \"$submodule_attr\"" &&
+	echo "a diff=d2x" >"$submodule_attr" &&
+
+	cat >expect <<-\EOF &&
+	submodule/a:(1|2)x(3|4)
+	EOF
+	git grep --textconv --recurse-submodules x >actual &&
+	test_cmp expect actual
+'
+
+test_expect_failure 'grep saves textconv cache in the appropriate repository' '
+	reset_and_clean &&
+	test_config_global diff.d2x_cached.textconv "sed -e \"s/d/x/\"" &&
+	test_config_global diff.d2x_cached.cachetextconv true &&
+	echo "a diff=d2x_cached" >submodule/.gitattributes &&
+
+	# We only read/write to the textconv cache when grepping from an OID,
+	# as the working tree file might have modifications.
+	git grep --textconv --cached --recurse-submodules x &&
+
+	super_textconv_cache="$(git rev-parse --git-path refs/notes/textconv/d2x_cached)" &&
+	sub_textconv_cache="$(git -C submodule rev-parse \
+			--path-format=absolute --git-path refs/notes/textconv/d2x_cached)" &&
+	test_path_is_missing "$super_textconv_cache" &&
+	test_path_is_file "$sub_textconv_cache"
+'
+
 test_done
diff --git a/t/t7816-grep-binary-pattern.sh b/t/t7816-grep-binary-pattern.sh
index 9d67a5f..fdb2355 100755
--- a/t/t7816-grep-binary-pattern.sh
+++ b/t/t7816-grep-binary-pattern.sh
@@ -2,6 +2,7 @@
 
 test_description='git grep with a binary pattern files'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./lib-gettext.sh
 
 nul_match_internal () {
diff --git a/t/t7900-maintenance.sh b/t/t7900-maintenance.sh
index fc16ac2..9b9f11a 100755
--- a/t/t7900-maintenance.sh
+++ b/t/t7900-maintenance.sh
@@ -20,6 +20,17 @@
 	fi
 }
 
+test_lazy_prereq SYSTEMD_ANALYZE '
+	systemd-analyze verify /lib/systemd/system/basic.target
+'
+
+test_systemd_analyze_verify () {
+	if test_have_prereq SYSTEMD_ANALYZE
+	then
+		systemd-analyze verify "$@"
+	fi
+}
+
 test_expect_success 'help text' '
 	test_expect_code 129 git maintenance -h 2>err &&
 	test_i18ngrep "usage: git maintenance <subcommand>" err &&
@@ -265,7 +276,7 @@
 
 	# Delete refs that have not been repacked in these packs.
 	git for-each-ref --format="delete %(refname)" \
-		refs/prefetch refs/tags >refs &&
+		refs/prefetch refs/tags refs/remotes >refs &&
 	git update-ref --stdin <refs &&
 
 	# Replace the object directory with this pack layout.
@@ -274,6 +285,10 @@
 	ls $packDir/*.pack >packs-before &&
 	test_line_count = 3 packs-before &&
 
+	# make sure we do not have any broken refs that were
+	# missed in the deletion above
+	git for-each-ref &&
+
 	# the job repacks the two into a new pack, but does not
 	# delete the old ones.
 	git maintenance run --task=incremental-repack &&
@@ -492,8 +507,21 @@
 		maintenance.repo "$(pwd)/$META"
 '
 
+test_expect_success 'start --scheduler=<scheduler>' '
+	test_expect_code 129 git maintenance start --scheduler=foo 2>err &&
+	test_i18ngrep "unrecognized --scheduler argument" err &&
+
+	test_expect_code 129 git maintenance start --no-scheduler 2>err &&
+	test_i18ngrep "unknown option" err &&
+
+	test_expect_code 128 \
+		env GIT_TEST_MAINT_SCHEDULER="launchctl:true,schtasks:true" \
+		git maintenance start --scheduler=crontab 2>err &&
+	test_i18ngrep "fatal: crontab scheduler is not available" err
+'
+
 test_expect_success 'start from empty cron table' '
-	GIT_TEST_MAINT_SCHEDULER="crontab:test-tool crontab cron.txt" git maintenance start &&
+	GIT_TEST_MAINT_SCHEDULER="crontab:test-tool crontab cron.txt" git maintenance start --scheduler=crontab &&
 
 	# start registers the repo
 	git config --get --global --fixed-value maintenance.repo "$(pwd)" &&
@@ -516,7 +544,7 @@
 
 test_expect_success 'start preserves existing schedule' '
 	echo "Important information!" >cron.txt &&
-	GIT_TEST_MAINT_SCHEDULER="crontab:test-tool crontab cron.txt" git maintenance start &&
+	GIT_TEST_MAINT_SCHEDULER="crontab:test-tool crontab cron.txt" git maintenance start --scheduler=crontab &&
 	grep "Important information!" cron.txt
 '
 
@@ -545,7 +573,7 @@
 	EOF
 
 	rm -f args &&
-	GIT_TEST_MAINT_SCHEDULER=launchctl:./print-args git maintenance start &&
+	GIT_TEST_MAINT_SCHEDULER=launchctl:./print-args git maintenance start --scheduler=launchctl &&
 
 	# start registers the repo
 	git config --get --global --fixed-value maintenance.repo "$(pwd)" &&
@@ -584,11 +612,11 @@
 
 test_expect_success 'use launchctl list to prevent extra work' '
 	# ensure we are registered
-	GIT_TEST_MAINT_SCHEDULER=launchctl:./print-args git maintenance start &&
+	GIT_TEST_MAINT_SCHEDULER=launchctl:./print-args git maintenance start --scheduler=launchctl &&
 
 	# do it again on a fresh args file
 	rm -f args &&
-	GIT_TEST_MAINT_SCHEDULER=launchctl:./print-args git maintenance start &&
+	GIT_TEST_MAINT_SCHEDULER=launchctl:./print-args git maintenance start --scheduler=launchctl &&
 
 	ls "$HOME/Library/LaunchAgents" >actual &&
 	cat >expect <<-\EOF &&
@@ -613,7 +641,7 @@
 	EOF
 
 	rm -f args &&
-	GIT_TEST_MAINT_SCHEDULER="schtasks:./print-args" git maintenance start &&
+	GIT_TEST_MAINT_SCHEDULER="schtasks:./print-args" git maintenance start --scheduler=schtasks &&
 
 	# start registers the repo
 	git config --get --global --fixed-value maintenance.repo "$(pwd)" &&
@@ -636,6 +664,83 @@
 	test_cmp expect args
 '
 
+test_expect_success 'start and stop Linux/systemd maintenance' '
+	write_script print-args <<-\EOF &&
+	printf "%s\n" "$*" >>args
+	EOF
+
+	XDG_CONFIG_HOME="$PWD" &&
+	export XDG_CONFIG_HOME &&
+	rm -f args &&
+	GIT_TEST_MAINT_SCHEDULER="systemctl:./print-args" git maintenance start --scheduler=systemd-timer &&
+
+	# start registers the repo
+	git config --get --global --fixed-value maintenance.repo "$(pwd)" &&
+
+	test_systemd_analyze_verify "systemd/user/git-maintenance@.service" &&
+
+	printf -- "--user enable --now git-maintenance@%s.timer\n" hourly daily weekly >expect &&
+	test_cmp expect args &&
+
+	rm -f args &&
+	GIT_TEST_MAINT_SCHEDULER="systemctl:./print-args" git maintenance stop &&
+
+	# stop does not unregister the repo
+	git config --get --global --fixed-value maintenance.repo "$(pwd)" &&
+
+	test_path_is_missing "systemd/user/git-maintenance@.timer" &&
+	test_path_is_missing "systemd/user/git-maintenance@.service" &&
+
+	printf -- "--user disable --now git-maintenance@%s.timer\n" hourly daily weekly >expect &&
+	test_cmp expect args
+'
+
+test_expect_success 'start and stop when several schedulers are available' '
+	write_script print-args <<-\EOF &&
+	printf "%s\n" "$*" | sed "s:gui/[0-9][0-9]*:gui/[UID]:; s:\(schtasks /create .* /xml\).*:\1:;" >>args
+	EOF
+
+	rm -f args &&
+	GIT_TEST_MAINT_SCHEDULER="systemctl:./print-args systemctl,launchctl:./print-args launchctl,schtasks:./print-args schtasks" git maintenance start --scheduler=systemd-timer &&
+	printf "launchctl bootout gui/[UID] $pfx/Library/LaunchAgents/org.git-scm.git.%s.plist\n" \
+		hourly daily weekly >expect &&
+	printf "schtasks /delete /tn Git Maintenance (%s) /f\n" \
+		hourly daily weekly >>expect &&
+	printf -- "systemctl --user enable --now git-maintenance@%s.timer\n" hourly daily weekly >>expect &&
+	test_cmp expect args &&
+
+	rm -f args &&
+	GIT_TEST_MAINT_SCHEDULER="systemctl:./print-args systemctl,launchctl:./print-args launchctl,schtasks:./print-args schtasks" git maintenance start --scheduler=launchctl &&
+	printf -- "systemctl --user disable --now git-maintenance@%s.timer\n" hourly daily weekly >expect &&
+	printf "schtasks /delete /tn Git Maintenance (%s) /f\n" \
+		hourly daily weekly >>expect &&
+	for frequency in hourly daily weekly
+	do
+		PLIST="$pfx/Library/LaunchAgents/org.git-scm.git.$frequency.plist" &&
+		echo "launchctl bootout gui/[UID] $PLIST" >>expect &&
+		echo "launchctl bootstrap gui/[UID] $PLIST" >>expect || return 1
+	done &&
+	test_cmp expect args &&
+
+	rm -f args &&
+	GIT_TEST_MAINT_SCHEDULER="systemctl:./print-args systemctl,launchctl:./print-args launchctl,schtasks:./print-args schtasks" git maintenance start --scheduler=schtasks &&
+	printf -- "systemctl --user disable --now git-maintenance@%s.timer\n" hourly daily weekly >expect &&
+	printf "launchctl bootout gui/[UID] $pfx/Library/LaunchAgents/org.git-scm.git.%s.plist\n" \
+		hourly daily weekly >>expect &&
+	printf "schtasks /create /tn Git Maintenance (%s) /f /xml\n" \
+		hourly daily weekly >>expect &&
+	test_cmp expect args &&
+
+	rm -f args &&
+	GIT_TEST_MAINT_SCHEDULER="systemctl:./print-args systemctl,launchctl:./print-args launchctl,schtasks:./print-args schtasks" git maintenance stop &&
+	printf -- "systemctl --user disable --now git-maintenance@%s.timer\n" hourly daily weekly >expect &&
+	printf "launchctl bootout gui/[UID] $pfx/Library/LaunchAgents/org.git-scm.git.%s.plist\n" \
+		hourly daily weekly >>expect &&
+	printf "schtasks /delete /tn Git Maintenance (%s) /f\n" \
+		hourly daily weekly >>expect &&
+	test_cmp expect args
+'
+
 test_expect_success 'register preserves existing strategy' '
 	git config maintenance.strategy none &&
 	git maintenance register &&
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index e28411b..eef2262 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -137,33 +137,110 @@
 # Stop execution and start a shell. This is useful for debugging tests.
 #
 # Be sure to remove all invocations of this command before submitting.
+# WARNING: the shell invoked by this helper does not have the same environment
+# as the one running the tests (shell variables and functions are not
+# available, and the options below further modify the environment). As such,
+# commands copied from a test script might behave differently than when
+# running the test.
+#
+# Usage: test_pause [options]
+#   -t
+#	Use your original TERM instead of test-lib.sh's "dumb".
+#	This usually restores color output in the invoked shell.
+#   -s
+#	Invoke $SHELL instead of $TEST_SHELL_PATH.
+#   -h
+#	Use your original HOME instead of test-lib.sh's "$TRASH_DIRECTORY".
+#	This allows you to use your regular shell environment and Git aliases.
+#	CAUTION: running commands copied from a test script into the paused shell
+#	might result in files in your HOME being overwritten.
+#   -a
+#	Shortcut for -t -s -h
 
 test_pause () {
-	"$SHELL_PATH" <&6 >&5 2>&7
+	PAUSE_TERM=$TERM &&
+	PAUSE_SHELL=$TEST_SHELL_PATH &&
+	PAUSE_HOME=$HOME &&
+	while test $# != 0
+	do
+		case "$1" in
+		-t)
+			PAUSE_TERM="$USER_TERM"
+			;;
+		-s)
+			PAUSE_SHELL="$SHELL"
+			;;
+		-h)
+			PAUSE_HOME="$USER_HOME"
+			;;
+		-a)
+			PAUSE_TERM="$USER_TERM"
+			PAUSE_SHELL="$SHELL"
+			PAUSE_HOME="$USER_HOME"
+			;;
+		*)
+			break
+			;;
+		esac
+		shift
+	done &&
+	TERM="$PAUSE_TERM" HOME="$PAUSE_HOME" "$PAUSE_SHELL" <&6 >&5 2>&7
 }
 
 # Wrap git with a debugger. Adding this to a command can make it easier
 # to understand what is going on in a failing test.
 #
+# Usage: debug [options] <git command>
+#   -d <debugger>
+#   --debugger=<debugger>
+#	Use <debugger> instead of GDB
+#   -t
+#	Use your original TERM instead of test-lib.sh's "dumb".
+#	This usually restores color output in the debugger.
+#	WARNING: the command being debugged might behave differently than when
+#	running the test.
+#
 # Examples:
 #     debug git checkout master
 #     debug --debugger=nemiver git $ARGS
 #     debug -d "valgrind --tool=memcheck --track-origins=yes" git $ARGS
 debug () {
-	case "$1" in
-	-d)
-		GIT_DEBUGGER="$2" &&
-		shift 2
-		;;
-	--debugger=*)
-		GIT_DEBUGGER="${1#*=}" &&
-		shift 1
-		;;
-	*)
-		GIT_DEBUGGER=1
-		;;
-	esac &&
-	GIT_DEBUGGER="${GIT_DEBUGGER}" "$@" <&6 >&5 2>&7
+	GIT_DEBUGGER=1 &&
+	DEBUG_TERM=$TERM &&
+	while test $# != 0
+	do
+		case "$1" in
+		-t)
+			DEBUG_TERM="$USER_TERM"
+			;;
+		-d)
+			GIT_DEBUGGER="$2" &&
+			shift
+			;;
+		--debugger=*)
+			GIT_DEBUGGER="${1#*=}"
+			;;
+		*)
+			break
+			;;
+		esac
+		shift
+	done &&
+
+	dotfiles=".gdbinit .lldbinit"
+
+	for dotfile in $dotfiles
+	do
+		dotfile="$USER_HOME/$dotfile" &&
+		test -f "$dotfile" && cp "$dotfile" "$HOME" || :
+	done &&
+
+	TERM="$DEBUG_TERM" GIT_DEBUGGER="${GIT_DEBUGGER}" "$@" <&6 >&5 2>&7 &&
+
+	for dotfile in $dotfiles
+	do
+		rm -f "$HOME/$dotfile"
+	done
 }
 
 # Usage: test_commit [options] <message> [<file> [<contents> [<tag>]]]
diff --git a/t/test-lib.sh b/t/test-lib.sh
index fc1e521..2679a75 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -534,7 +534,7 @@
 # when case-folding filenames
 u200c=$(printf '\342\200\214')
 
-export _x05 _x35 _x40 _z40 LF u200c EMPTY_TREE EMPTY_BLOB ZERO_OID OID_REGEX
+export _x05 _x35 LF u200c EMPTY_TREE EMPTY_BLOB ZERO_OID OID_REGEX
 
 # Each test should start with something like this, after copyright notices:
 #
@@ -585,20 +585,37 @@
 	}
 fi
 
+USER_TERM="$TERM"
 TERM=dumb
-export TERM
+export TERM USER_TERM
 
-error () {
-	say_color error "error: $*"
+_error_exit () {
 	finalize_junit_xml
 	GIT_EXIT_OK=t
 	exit 1
 }
 
+error () {
+	say_color error "error: $*"
+	_error_exit
+}
+
 BUG () {
 	error >&7 "bug in the test script: $*"
 }
 
+BAIL_OUT () {
+	test $# -ne 1 && BUG "1 param"
+
+	# Do not change "Bail out! " string. It's part of TAP syntax:
+	# https://testanything.org/tap-specification.html
+	local bail_out="Bail out! "
+	local message="$1"
+
+	say_color error $bail_out "$message"
+	_error_exit
+}
+
 say () {
 	say_color info "$*"
 }
@@ -607,9 +624,7 @@
 then
 	if test "$verbose" = t || test -n "$verbose_only"
 	then
-		printf 'Bail out! %s\n' \
-		 'verbose mode forbidden under TAP harness; try --verbose-log'
-		exit 1
+		BAIL_OUT 'verbose mode forbidden under TAP harness; try --verbose-log'
 	fi
 fi
 
@@ -719,7 +734,7 @@
 	say_color error "not ok $test_count - $1"
 	shift
 	printf '%s\n' "$*" | sed -e 's/^/#	/'
-	test "$immediate" = "" || { finalize_junit_xml; GIT_EXIT_OK=t; exit 1; }
+	test "$immediate" = "" || _error_exit
 }
 
 test_known_broken_ok_ () {
@@ -1380,13 +1395,46 @@
 	test_done
 fi
 
+# skip non-whitelisted tests 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
+
+		if ! test_bool_env TEST_PASSES_SANITIZE_LEAK false
+		then
+			skip_all="skipping $this_test under GIT_TEST_PASSING_SANITIZE_LEAK=true"
+			test_done
+		fi
+	fi
+elif test_bool_env GIT_TEST_PASSING_SANITIZE_LEAK false
+then
+	BAIL_OUT "GIT_TEST_PASSING_SANITIZE_LEAK=true has no effect except when compiled with SANITIZE=leak"
+fi
+
 # Last-minute variable setup
+USER_HOME="$HOME"
 HOME="$TRASH_DIRECTORY"
 GNUPGHOME="$HOME/gnupg-home-not-used"
-export HOME GNUPGHOME
+export HOME GNUPGHOME USER_HOME
+
+# "rm -rf" existing trash directory, even if a previous run left it
+# with bad permissions.
+remove_trash_directory () {
+	dir="$1"
+	if ! rm -rf "$dir" 2>/dev/null
+	then
+		chmod -R u+rwx "$dir"
+		rm -rf "$dir"
+	fi
+	! test -d "$dir"
+}
 
 # Test repository
-rm -fr "$TRASH_DIRECTORY" || {
+remove_trash_directory "$TRASH_DIRECTORY" || {
 	GIT_EXIT_OK=t
 	echo >&5 "FATAL: Cannot prepare test area"
 	exit 1
@@ -1423,10 +1471,9 @@
 fi
 
 # Convenience
-# A regexp to match 5, 35 and 40 hexdigits
+# A regexp to match 5 and 35 hexdigits
 _x05='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
 _x35="$_x05$_x05$_x05$_x05$_x05$_x05$_x05"
-_x40="$_x35$_x05"
 
 test_oid_init
 
@@ -1435,7 +1482,6 @@
 OIDPATH_REGEX=$(test_oid_to_path $ZERO_OID | sed -e 's/0/[0-9a-f]/g')
 EMPTY_TREE=$(test_oid empty_tree)
 EMPTY_BLOB=$(test_oid empty_blob)
-_z40=$ZERO_OID
 
 # Provide an implementation of the 'yes' utility; the upper bound
 # limit is there to help Windows that cannot stop this loop from
@@ -1534,6 +1580,7 @@
 test -n "$USE_LIBPCRE2" && test_set_prereq PCRE
 test -n "$USE_LIBPCRE2" && test_set_prereq LIBPCRE2
 test -z "$NO_GETTEXT" && test_set_prereq GETTEXT
+test -n "$SANITIZE_LEAK" && test_set_prereq SANITIZE_LEAK
 
 if test -z "$GIT_TEST_CHECK_CACHE_TREE"
 then
@@ -1709,10 +1756,6 @@
 	esac
 '
 
-test_lazy_prereq REBASE_P '
-	test -z "$GIT_TEST_SKIP_REBASE_P"
-'
-
 # Ensure that no test accidentally triggers a Git command
 # that runs the actual maintenance scheduler, affecting a user's
 # system permanently.
diff --git a/trace.h b/trace.h
index 0dbbad0..e259840 100644
--- a/trace.h
+++ b/trace.h
@@ -89,7 +89,7 @@
 
 extern struct trace_key trace_default_key;
 
-#define TRACE_KEY_INIT(name) { "GIT_TRACE_" #name, 0, 0, 0 }
+#define TRACE_KEY_INIT(name) { .key = "GIT_TRACE_" #name }
 extern struct trace_key trace_perf_key;
 extern struct trace_key trace_setup_key;
 
diff --git a/trace2.c b/trace2.c
index 256120c..b2d4715 100644
--- a/trace2.c
+++ b/trace2.c
@@ -260,6 +260,19 @@
 			tgt_j->pfn_command_path_fl(file, line, pathname);
 }
 
+void trace2_cmd_ancestry_fl(const char *file, int line, const char **parent_names)
+{
+	struct tr2_tgt *tgt_j;
+	int j;
+
+	if (!trace2_enabled)
+		return;
+
+	for_each_wanted_builtin (j, tgt_j)
+		if (tgt_j->pfn_command_ancestry_fl)
+			tgt_j->pfn_command_ancestry_fl(file, line, parent_names);
+}
+
 void trace2_cmd_name_fl(const char *file, int line, const char *name)
 {
 	struct tr2_tgt *tgt_j;
@@ -381,6 +394,37 @@
 						 us_elapsed_child);
 }
 
+void trace2_child_ready_fl(const char *file, int line,
+			   struct child_process *cmd,
+			   const char *ready)
+{
+	struct tr2_tgt *tgt_j;
+	int j;
+	uint64_t us_now;
+	uint64_t us_elapsed_absolute;
+	uint64_t us_elapsed_child;
+
+	if (!trace2_enabled)
+		return;
+
+	us_now = getnanotime() / 1000;
+	us_elapsed_absolute = tr2tls_absolute_elapsed(us_now);
+
+	if (cmd->trace2_child_us_start)
+		us_elapsed_child = us_now - cmd->trace2_child_us_start;
+	else
+		us_elapsed_child = 0;
+
+	for_each_wanted_builtin (j, tgt_j)
+		if (tgt_j->pfn_child_ready_fl)
+			tgt_j->pfn_child_ready_fl(file, line,
+						  us_elapsed_absolute,
+						  cmd->trace2_child_id,
+						  cmd->pid,
+						  ready,
+						  us_elapsed_child);
+}
+
 int trace2_exec_fl(const char *file, int line, const char *exe,
 		   const char **argv)
 {
diff --git a/trace2.h b/trace2.h
index 49c96ec..0cc7b5f 100644
--- a/trace2.h
+++ b/trace2.h
@@ -134,6 +134,16 @@
 #define trace2_cmd_path(p) trace2_cmd_path_fl(__FILE__, __LINE__, (p))
 
 /*
+ * Emit an 'ancestry' event with the process name of the current process's
+ * parent process.
+ * This gives post-processors a way to determine what invoked the command and
+ * learn more about usage patterns.
+ */
+void trace2_cmd_ancestry_fl(const char *file, int line, const char **parent_names);
+
+#define trace2_cmd_ancestry(v) trace2_cmd_ancestry_fl(__FILE__, __LINE__, (v))
+
+/*
  * Emit a 'cmd_name' event with the canonical name of the command.
  * This gives post-processors a simple field to identify the command
  * without having to parse the argv.
@@ -244,6 +254,31 @@
 	trace2_child_exit_fl(__FILE__, __LINE__, (cmd), (code))
 
 /**
+ * Emits a "child_ready" message containing the "child-id" and a flag
+ * indicating whether the child was considered "ready" when we
+ * released it.
+ *
+ * This function should be called after starting a daemon process in
+ * the background (and after giving it sufficient time to boot
+ * up) to indicate that we no longer control or own it.
+ *
+ * The "ready" argument should contain one of { "ready", "timeout",
+ * "error" } to indicate the state of the running daemon when we
+ * released it.
+ *
+ * If the daemon process fails to start or it exits or is terminated
+ * while we are still waiting for it, the caller should emit a
+ * regular "child_exit" to report the normal process exit information.
+ *
+ */
+void trace2_child_ready_fl(const char *file, int line,
+			   struct child_process *cmd,
+			   const char *ready);
+
+#define trace2_child_ready(cmd, ready) \
+	trace2_child_ready_fl(__FILE__, __LINE__, (cmd), (ready))
+
+/**
  * Emit an 'exec' event prior to calling one of exec(), execv(),
  * execvp(), and etc.  On Unix-derived systems, this will be the
  * last event emitted for the current process, unless the exec
@@ -492,13 +527,7 @@
 	TRACE2_PROCESS_INFO_EXIT,
 };
 
-#if defined(GIT_WINDOWS_NATIVE)
 void trace2_collect_process_info(enum trace2_process_info_reason reason);
-#else
-#define trace2_collect_process_info(reason) \
-	do {                                \
-	} while (0)
-#endif
 
 const char *trace2_session_id(void);
 
diff --git a/trace2/tr2_tgt.h b/trace2/tr2_tgt.h
index 7b90469..65f94e1 100644
--- a/trace2/tr2_tgt.h
+++ b/trace2/tr2_tgt.h
@@ -27,6 +27,8 @@
 
 typedef void(tr2_tgt_evt_command_path_fl_t)(const char *file, int line,
 					    const char *command_path);
+typedef void(tr2_tgt_evt_command_ancestry_fl_t)(const char *file, int line,
+						const char **parent_names);
 typedef void(tr2_tgt_evt_command_name_fl_t)(const char *file, int line,
 					    const char *name,
 					    const char *hierarchy);
@@ -43,6 +45,10 @@
 					  uint64_t us_elapsed_absolute, int cid,
 					  int pid, int code,
 					  uint64_t us_elapsed_child);
+typedef void(tr2_tgt_evt_child_ready_fl_t)(const char *file, int line,
+					   uint64_t us_elapsed_absolute,
+					   int cid, int pid, const char *ready,
+					   uint64_t us_elapsed_child);
 
 typedef void(tr2_tgt_evt_thread_start_fl_t)(const char *file, int line,
 					    uint64_t us_elapsed_absolute);
@@ -108,11 +114,13 @@
 	tr2_tgt_evt_atexit_t                    *pfn_atexit;
 	tr2_tgt_evt_error_va_fl_t               *pfn_error_va_fl;
 	tr2_tgt_evt_command_path_fl_t           *pfn_command_path_fl;
+	tr2_tgt_evt_command_ancestry_fl_t	*pfn_command_ancestry_fl;
 	tr2_tgt_evt_command_name_fl_t           *pfn_command_name_fl;
 	tr2_tgt_evt_command_mode_fl_t           *pfn_command_mode_fl;
 	tr2_tgt_evt_alias_fl_t                  *pfn_alias_fl;
 	tr2_tgt_evt_child_start_fl_t            *pfn_child_start_fl;
 	tr2_tgt_evt_child_exit_fl_t             *pfn_child_exit_fl;
+	tr2_tgt_evt_child_ready_fl_t            *pfn_child_ready_fl;
 	tr2_tgt_evt_thread_start_fl_t           *pfn_thread_start_fl;
 	tr2_tgt_evt_thread_exit_fl_t            *pfn_thread_exit_fl;
 	tr2_tgt_evt_exec_fl_t                   *pfn_exec_fl;
diff --git a/trace2/tr2_tgt_event.c b/trace2/tr2_tgt_event.c
index 6353e8a..70cfc2f 100644
--- a/trace2/tr2_tgt_event.c
+++ b/trace2/tr2_tgt_event.c
@@ -261,6 +261,26 @@
 	jw_release(&jw);
 }
 
+static void fn_command_ancestry_fl(const char *file, int line, const char **parent_names)
+{
+	const char *event_name = "cmd_ancestry";
+	const char *parent_name = NULL;
+	struct json_writer jw = JSON_WRITER_INIT;
+
+	jw_object_begin(&jw, 0);
+	event_fmt_prepare(event_name, file, line, NULL, &jw);
+	jw_object_inline_begin_array(&jw, "ancestry");
+
+	while ((parent_name = *parent_names++))
+		jw_array_string(&jw, parent_name);
+
+	jw_end(&jw); /* 'ancestry' array */
+	jw_end(&jw); /* event object */
+
+	tr2_dst_write_line(&tr2dst_event, &jw.json);
+	jw_release(&jw);
+}
+
 static void fn_command_name_fl(const char *file, int line, const char *name,
 			       const char *hierarchy)
 {
@@ -363,6 +383,27 @@
 	jw_release(&jw);
 }
 
+static void fn_child_ready_fl(const char *file, int line,
+			      uint64_t us_elapsed_absolute, int cid, int pid,
+			      const char *ready, uint64_t us_elapsed_child)
+{
+	const char *event_name = "child_ready";
+	struct json_writer jw = JSON_WRITER_INIT;
+	double t_rel = (double)us_elapsed_child / 1000000.0;
+
+	jw_object_begin(&jw, 0);
+	event_fmt_prepare(event_name, file, line, NULL, &jw);
+	jw_object_intmax(&jw, "child_id", cid);
+	jw_object_intmax(&jw, "pid", pid);
+	jw_object_string(&jw, "ready", ready);
+	jw_object_double(&jw, "t_rel", 6, t_rel);
+	jw_end(&jw);
+
+	tr2_dst_write_line(&tr2dst_event, &jw.json);
+
+	jw_release(&jw);
+}
+
 static void fn_thread_start_fl(const char *file, int line,
 			       uint64_t us_elapsed_absolute)
 {
@@ -584,11 +625,13 @@
 	fn_atexit,
 	fn_error_va_fl,
 	fn_command_path_fl,
+	fn_command_ancestry_fl,
 	fn_command_name_fl,
 	fn_command_mode_fl,
 	fn_alias_fl,
 	fn_child_start_fl,
 	fn_child_exit_fl,
+	fn_child_ready_fl,
 	fn_thread_start_fl,
 	fn_thread_exit_fl,
 	fn_exec_fl,
diff --git a/trace2/tr2_tgt_normal.c b/trace2/tr2_tgt_normal.c
index 31b602c..58d9e43 100644
--- a/trace2/tr2_tgt_normal.c
+++ b/trace2/tr2_tgt_normal.c
@@ -160,6 +160,24 @@
 	strbuf_release(&buf_payload);
 }
 
+static void fn_command_ancestry_fl(const char *file, int line, const char **parent_names)
+{
+	const char *parent_name = NULL;
+	struct strbuf buf_payload = STRBUF_INIT;
+
+	/* cmd_ancestry parent <- grandparent <- great-grandparent */
+	strbuf_addstr(&buf_payload, "cmd_ancestry ");
+	while ((parent_name = *parent_names++)) {
+		strbuf_addstr(&buf_payload, parent_name);
+		/* if we'll write another one after this, add a delimiter */
+		if (parent_names && *parent_names)
+			strbuf_addstr(&buf_payload, " <- ");
+	}
+
+	normal_io_write_fl(file, line, &buf_payload);
+	strbuf_release(&buf_payload);
+}
+
 static void fn_command_name_fl(const char *file, int line, const char *name,
 			       const char *hierarchy)
 {
@@ -233,6 +251,19 @@
 	strbuf_release(&buf_payload);
 }
 
+static void fn_child_ready_fl(const char *file, int line,
+			      uint64_t us_elapsed_absolute, int cid, int pid,
+			      const char *ready, uint64_t us_elapsed_child)
+{
+	struct strbuf buf_payload = STRBUF_INIT;
+	double elapsed = (double)us_elapsed_child / 1000000.0;
+
+	strbuf_addf(&buf_payload, "child_ready[%d] pid:%d ready:%s elapsed:%.6f",
+		    cid, pid, ready, elapsed);
+	normal_io_write_fl(file, line, &buf_payload);
+	strbuf_release(&buf_payload);
+}
+
 static void fn_exec_fl(const char *file, int line, uint64_t us_elapsed_absolute,
 		       int exec_id, const char *exe, const char **argv)
 {
@@ -306,11 +337,13 @@
 	fn_atexit,
 	fn_error_va_fl,
 	fn_command_path_fl,
+	fn_command_ancestry_fl,
 	fn_command_name_fl,
 	fn_command_mode_fl,
 	fn_alias_fl,
 	fn_child_start_fl,
 	fn_child_exit_fl,
+	fn_child_ready_fl,
 	NULL, /* thread_start */
 	NULL, /* thread_exit */
 	fn_exec_fl,
diff --git a/trace2/tr2_tgt_perf.c b/trace2/tr2_tgt_perf.c
index a8018f1..e4acca1 100644
--- a/trace2/tr2_tgt_perf.c
+++ b/trace2/tr2_tgt_perf.c
@@ -253,6 +253,21 @@
 	strbuf_release(&buf_payload);
 }
 
+static void fn_command_ancestry_fl(const char *file, int line, const char **parent_names)
+{
+	const char *event_name = "cmd_ancestry";
+	struct strbuf buf_payload = STRBUF_INIT;
+
+	strbuf_addstr(&buf_payload, "ancestry:[");
+	/* It's not an argv but the rules are basically the same. */
+	sq_append_quote_argv_pretty(&buf_payload, parent_names);
+	strbuf_addch(&buf_payload, ']');
+
+	perf_io_write_fl(file, line, event_name, NULL, NULL, NULL, NULL,
+			 &buf_payload);
+	strbuf_release(&buf_payload);
+}
+
 static void fn_command_name_fl(const char *file, int line, const char *name,
 			       const char *hierarchy)
 {
@@ -345,6 +360,20 @@
 	strbuf_release(&buf_payload);
 }
 
+static void fn_child_ready_fl(const char *file, int line,
+			      uint64_t us_elapsed_absolute, int cid, int pid,
+			      const char *ready, uint64_t us_elapsed_child)
+{
+	const char *event_name = "child_ready";
+	struct strbuf buf_payload = STRBUF_INIT;
+
+	strbuf_addf(&buf_payload, "[ch%d] pid:%d ready:%s", cid, pid, ready);
+
+	perf_io_write_fl(file, line, event_name, NULL, &us_elapsed_absolute,
+			 &us_elapsed_child, NULL, &buf_payload);
+	strbuf_release(&buf_payload);
+}
+
 static void fn_thread_start_fl(const char *file, int line,
 			       uint64_t us_elapsed_absolute)
 {
@@ -532,11 +561,13 @@
 	fn_atexit,
 	fn_error_va_fl,
 	fn_command_path_fl,
+	fn_command_ancestry_fl,
 	fn_command_name_fl,
 	fn_command_mode_fl,
 	fn_alias_fl,
 	fn_child_start_fl,
 	fn_child_exit_fl,
+	fn_child_ready_fl,
 	fn_thread_start_fl,
 	fn_thread_exit_fl,
 	fn_exec_fl,
diff --git a/trace2/tr2_tls.c b/trace2/tr2_tls.c
index 067c237..7da94ab 100644
--- a/trace2/tr2_tls.c
+++ b/trace2/tr2_tls.c
@@ -95,6 +95,7 @@
 
 	pthread_setspecific(tr2tls_key, NULL);
 
+	strbuf_release(&ctx->thread_name);
 	free(ctx->array_us_start);
 	free(ctx);
 }
diff --git a/transport-helper.c b/transport-helper.c
index 4be035e..a0297b0 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -671,8 +671,8 @@
 static struct ref *get_refs_list_using_list(struct transport *transport,
 					    int for_push);
 
-static int fetch(struct transport *transport,
-		 int nr_heads, struct ref **to_fetch)
+static int fetch_refs(struct transport *transport,
+		      int nr_heads, struct ref **to_fetch)
 {
 	struct helper_data *data = transport->data;
 	int i, count;
@@ -681,7 +681,7 @@
 
 	if (process_connect(transport, 0)) {
 		do_take_over(transport);
-		return transport->vtable->fetch(transport, nr_heads, to_fetch);
+		return transport->vtable->fetch_refs(transport, nr_heads, to_fetch);
 	}
 
 	/*
@@ -845,6 +845,10 @@
 			forced = 1;
 			FREE_AND_NULL(msg);
 		}
+		else if (!strcmp(msg, "expecting report")) {
+			status = REF_STATUS_EXPECTING_REPORT;
+			FREE_AND_NULL(msg);
+		}
 	}
 
 	if (state->hint)
@@ -1261,12 +1265,12 @@
 }
 
 static struct transport_vtable vtable = {
-	set_helper_option,
-	get_refs_list,
-	fetch,
-	push_refs,
-	connect_helper,
-	release_helper
+	.set_option	= set_helper_option,
+	.get_refs_list	= get_refs_list,
+	.fetch_refs	= fetch_refs,
+	.push_refs	= push_refs,
+	.connect	= connect_helper,
+	.disconnect	= release_helper
 };
 
 int transport_helper_init(struct transport *transport, const char *name)
diff --git a/transport-internal.h b/transport-internal.h
index b60f1ba..c4ca0b7 100644
--- a/transport-internal.h
+++ b/transport-internal.h
@@ -34,7 +34,7 @@
 	 * get_refs_list(), it should set the old_sha1 fields in the
 	 * provided refs now.
 	 **/
-	int (*fetch)(struct transport *transport, int refs_nr, struct ref **refs);
+	int (*fetch_refs)(struct transport *transport, int refs_nr, struct ref **refs);
 
 	/**
 	 * Push the objects and refs. Send the necessary objects, and
diff --git a/transport.c b/transport.c
index 17e9629..e4f1dec 100644
--- a/transport.c
+++ b/transport.c
@@ -1,7 +1,7 @@
 #include "cache.h"
 #include "config.h"
 #include "transport.h"
-#include "run-command.h"
+#include "hook.h"
 #include "pkt-line.h"
 #include "fetch-pack.h"
 #include "remote.h"
@@ -162,12 +162,16 @@
 			       int nr_heads, struct ref **to_fetch)
 {
 	struct bundle_transport_data *data = transport->data;
+	struct strvec extra_index_pack_args = STRVEC_INIT;
 	int ret;
 
+	if (transport->progress)
+		strvec_push(&extra_index_pack_args, "-v");
+
 	if (!data->get_refs_from_bundle_called)
 		get_refs_from_bundle(transport, 0, NULL);
 	ret = unbundle(the_repository, &data->header, data->fd,
-			   transport->progress ? BUNDLE_VERBOSE : 0);
+		       &extra_index_pack_args);
 	transport->hash_algo = data->header.hash_algo;
 	return ret;
 }
@@ -883,12 +887,10 @@
 }
 
 static struct transport_vtable taken_over_vtable = {
-	NULL,
-	get_refs_via_connect,
-	fetch_refs_via_pack,
-	git_transport_push,
-	NULL,
-	disconnect_git
+	.get_refs_list	= get_refs_via_connect,
+	.fetch_refs	= fetch_refs_via_pack,
+	.push_refs	= git_transport_push,
+	.disconnect	= disconnect_git
 };
 
 void transport_take_over(struct transport *transport,
@@ -1032,21 +1034,17 @@
 }
 
 static struct transport_vtable bundle_vtable = {
-	NULL,
-	get_refs_from_bundle,
-	fetch_refs_from_bundle,
-	NULL,
-	NULL,
-	close_bundle
+	.get_refs_list	= get_refs_from_bundle,
+	.fetch_refs	= fetch_refs_from_bundle,
+	.disconnect	= close_bundle
 };
 
 static struct transport_vtable builtin_smart_vtable = {
-	NULL,
-	get_refs_via_connect,
-	fetch_refs_via_pack,
-	git_transport_push,
-	connect_git,
-	disconnect_git
+	.get_refs_list	= get_refs_via_connect,
+	.fetch_refs	= fetch_refs_via_pack,
+	.push_refs	= git_transport_push,
+	.connect	= connect_git,
+	.disconnect	= disconnect_git
 };
 
 struct transport *transport_get(struct remote *remote, const char *url)
@@ -1453,7 +1451,7 @@
 			heads[nr_heads++] = rm;
 	}
 
-	rc = transport->vtable->fetch(transport, nr_heads, heads);
+	rc = transport->vtable->fetch_refs(transport, nr_heads, heads);
 
 	free(heads);
 	return rc;
diff --git a/transport.h b/transport.h
index 1cbab11..8bb4c8b 100644
--- a/transport.h
+++ b/transport.h
@@ -262,7 +262,9 @@
 	 */
 	char *unborn_head_target;
 };
-#define TRANSPORT_LS_REFS_OPTIONS_INIT { STRVEC_INIT }
+#define TRANSPORT_LS_REFS_OPTIONS_INIT { \
+	.ref_prefixes = STRVEC_INIT, \
+}
 
 /*
  * Retrieve refs from a remote.
diff --git a/unpack-trees.c b/unpack-trees.c
index f07304f..89ca95c 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -111,17 +111,17 @@
 	strvec_init(&opts->msgs_to_free);
 
 	if (!strcmp(cmd, "checkout"))
-		msg = advice_commit_before_merge
+		msg = advice_enabled(ADVICE_COMMIT_BEFORE_MERGE)
 		      ? _("Your local changes to the following files would be overwritten by checkout:\n%%s"
 			  "Please commit your changes or stash them before you switch branches.")
 		      : _("Your local changes to the following files would be overwritten by checkout:\n%%s");
 	else if (!strcmp(cmd, "merge"))
-		msg = advice_commit_before_merge
+		msg = advice_enabled(ADVICE_COMMIT_BEFORE_MERGE)
 		      ? _("Your local changes to the following files would be overwritten by merge:\n%%s"
 			  "Please commit your changes or stash them before you merge.")
 		      : _("Your local changes to the following files would be overwritten by merge:\n%%s");
 	else
-		msg = advice_commit_before_merge
+		msg = advice_enabled(ADVICE_COMMIT_BEFORE_MERGE)
 		      ? _("Your local changes to the following files would be overwritten by %s:\n%%s"
 			  "Please commit your changes or stash them before you %s.")
 		      : _("Your local changes to the following files would be overwritten by %s:\n%%s");
@@ -132,17 +132,17 @@
 		_("Updating the following directories would lose untracked files in them:\n%s");
 
 	if (!strcmp(cmd, "checkout"))
-		msg = advice_commit_before_merge
+		msg = advice_enabled(ADVICE_COMMIT_BEFORE_MERGE)
 		      ? _("The following untracked working tree files would be removed by checkout:\n%%s"
 			  "Please move or remove them before you switch branches.")
 		      : _("The following untracked working tree files would be removed by checkout:\n%%s");
 	else if (!strcmp(cmd, "merge"))
-		msg = advice_commit_before_merge
+		msg = advice_enabled(ADVICE_COMMIT_BEFORE_MERGE)
 		      ? _("The following untracked working tree files would be removed by merge:\n%%s"
 			  "Please move or remove them before you merge.")
 		      : _("The following untracked working tree files would be removed by merge:\n%%s");
 	else
-		msg = advice_commit_before_merge
+		msg = advice_enabled(ADVICE_COMMIT_BEFORE_MERGE)
 		      ? _("The following untracked working tree files would be removed by %s:\n%%s"
 			  "Please move or remove them before you %s.")
 		      : _("The following untracked working tree files would be removed by %s:\n%%s");
@@ -150,17 +150,17 @@
 		strvec_pushf(&opts->msgs_to_free, msg, cmd, cmd);
 
 	if (!strcmp(cmd, "checkout"))
-		msg = advice_commit_before_merge
+		msg = advice_enabled(ADVICE_COMMIT_BEFORE_MERGE)
 		      ? _("The following untracked working tree files would be overwritten by checkout:\n%%s"
 			  "Please move or remove them before you switch branches.")
 		      : _("The following untracked working tree files would be overwritten by checkout:\n%%s");
 	else if (!strcmp(cmd, "merge"))
-		msg = advice_commit_before_merge
+		msg = advice_enabled(ADVICE_COMMIT_BEFORE_MERGE)
 		      ? _("The following untracked working tree files would be overwritten by merge:\n%%s"
 			  "Please move or remove them before you merge.")
 		      : _("The following untracked working tree files would be overwritten by merge:\n%%s");
 	else
-		msg = advice_commit_before_merge
+		msg = advice_enabled(ADVICE_COMMIT_BEFORE_MERGE)
 		      ? _("The following untracked working tree files would be overwritten by %s:\n%%s"
 			  "Please move or remove them before you %s.")
 		      : _("The following untracked working tree files would be overwritten by %s:\n%%s");
@@ -1255,7 +1255,7 @@
 static struct cache_entry *find_cache_entry(struct traverse_info *info,
 					    const struct name_entry *p)
 {
-	struct cache_entry *ce;
+	const char *path;
 	int pos = find_cache_pos(info, p->path, p->pathlen);
 	struct unpack_trees_options *o = info->data;
 
@@ -1281,9 +1281,11 @@
 	 * paths (e.g. "subdir-").
 	 */
 	while (pos >= 0) {
-		ce = o->src_index->cache[pos];
+		struct cache_entry *ce = o->src_index->cache[pos];
 
-		if (strncmp(ce->name, p->path, p->pathlen))
+		if (!skip_prefix(ce->name, info->traverse_path, &path) ||
+		    strncmp(path, p->path, p->pathlen) ||
+		    path[p->pathlen] != '/')
 			return NULL;
 
 		if (S_ISSPARSEDIR(ce->ce_mode) &&
@@ -1692,9 +1694,15 @@
 	static struct cache_entry *dfc;
 	struct pattern_list pl;
 	int free_pattern_list = 0;
+	struct dir_struct dir = DIR_INIT;
+
+	if (o->reset == UNPACK_RESET_INVALID)
+		BUG("o->reset had a value of 1; should be UNPACK_TREES_*_UNTRACKED");
 
 	if (len > MAX_UNPACK_TREES)
 		die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
+	if (o->dir)
+		BUG("o->dir is for internal use only");
 
 	trace_performance_enter();
 	trace2_region_enter("unpack_trees", "unpack_trees", the_repository);
@@ -1705,6 +1713,16 @@
 		ensure_full_index(o->dst_index);
 	}
 
+	if (o->reset == UNPACK_RESET_OVERWRITE_UNTRACKED &&
+	    o->preserve_ignored)
+		BUG("UNPACK_RESET_OVERWRITE_UNTRACKED incompatible with preserved ignored files");
+
+	if (!o->preserve_ignored) {
+		o->dir = &dir;
+		o->dir->flags |= DIR_SHOW_IGNORED;
+		setup_standard_excludes(o->dir);
+	}
+
 	if (!core_apply_sparse_checkout || !o->update)
 		o->skip_sparse_checkout = 1;
 	if (!o->skip_sparse_checkout && !o->pl) {
@@ -1866,6 +1884,10 @@
 done:
 	if (free_pattern_list)
 		clear_pattern_list(&pl);
+	if (o->dir) {
+		dir_clear(o->dir);
+		o->dir = NULL;
+	}
 	trace2_region_leave("unpack_trees", "unpack_trees", the_repository);
 	trace_performance_leave("unpack_trees");
 	return ret;
@@ -2134,9 +2156,10 @@
 	if (o->dir)
 		d.exclude_per_dir = o->dir->exclude_per_dir;
 	i = read_directory(&d, o->src_index, pathbuf, namelen+1, NULL);
+	dir_clear(&d);
+	free(pathbuf);
 	if (i)
 		return add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
-	free(pathbuf);
 	return cnt;
 }
 
@@ -2156,9 +2179,15 @@
 	return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
 }
 
+enum absent_checking_type {
+	COMPLETELY_ABSENT,
+	ABSENT_ANY_DIRECTORY
+};
+
 static int check_ok_to_remove(const char *name, int len, int dtype,
 			      const struct cache_entry *ce, struct stat *st,
 			      enum unpack_trees_error_types error_type,
+			      enum absent_checking_type absent_type,
 			      struct unpack_trees_options *o)
 {
 	const struct cache_entry *result;
@@ -2193,6 +2222,10 @@
 		return 0;
 	}
 
+	/* If we only care about directories, then we can remove */
+	if (absent_type == ABSENT_ANY_DIRECTORY)
+		return 0;
+
 	/*
 	 * The previous round may already have decided to
 	 * delete this path, which is in a subdirectory that
@@ -2213,12 +2246,14 @@
  */
 static int verify_absent_1(const struct cache_entry *ce,
 			   enum unpack_trees_error_types error_type,
+			   enum absent_checking_type absent_type,
 			   struct unpack_trees_options *o)
 {
 	int len;
 	struct stat st;
 
-	if (o->index_only || o->reset || !o->update)
+	if (o->index_only || !o->update ||
+	    o->reset == UNPACK_RESET_OVERWRITE_UNTRACKED)
 		return 0;
 
 	len = check_leading_path(ce->name, ce_namelen(ce), 0);
@@ -2238,7 +2273,8 @@
 								NULL, o);
 			else
 				ret = check_ok_to_remove(path, len, DT_UNKNOWN, NULL,
-							 &st, error_type, o);
+							 &st, error_type,
+							 absent_type, o);
 		}
 		free(path);
 		return ret;
@@ -2253,7 +2289,7 @@
 
 		return check_ok_to_remove(ce->name, ce_namelen(ce),
 					  ce_to_dtype(ce), ce, &st,
-					  error_type, o);
+					  error_type, absent_type, o);
 	}
 }
 
@@ -2263,14 +2299,23 @@
 {
 	if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
 		return 0;
-	return verify_absent_1(ce, error_type, o);
+	return verify_absent_1(ce, error_type, COMPLETELY_ABSENT, o);
+}
+
+static int verify_absent_if_directory(const struct cache_entry *ce,
+				      enum unpack_trees_error_types error_type,
+				      struct unpack_trees_options *o)
+{
+	if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
+		return 0;
+	return verify_absent_1(ce, error_type, ABSENT_ANY_DIRECTORY, o);
 }
 
 static int verify_absent_sparse(const struct cache_entry *ce,
 				enum unpack_trees_error_types error_type,
 				struct unpack_trees_options *o)
 {
-	return verify_absent_1(ce, error_type, o);
+	return verify_absent_1(ce, error_type, COMPLETELY_ABSENT, o);
 }
 
 static int merged_entry(const struct cache_entry *ce,
@@ -2344,6 +2389,12 @@
 		 * Previously unmerged entry left as an existence
 		 * marker by read_index_unmerged();
 		 */
+		if (verify_absent_if_directory(merge,
+				  ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
+			discard_cache_entry(merge);
+			return -1;
+		}
+
 		invalidate_ce_path(old, o);
 	}
 
@@ -2361,7 +2412,10 @@
 		if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
 			return -1;
 		return 0;
+	} else if (verify_absent_if_directory(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o)) {
+		return -1;
 	}
+
 	if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
 		return -1;
 	add_entry(o, ce, CE_REMOVE, 0);
diff --git a/unpack-trees.h b/unpack-trees.h
index 2d88b19..71ffb7e 100644
--- a/unpack-trees.h
+++ b/unpack-trees.h
@@ -45,10 +45,17 @@
  */
 void clear_unpack_trees_porcelain(struct unpack_trees_options *opts);
 
+enum unpack_trees_reset_type {
+	UNPACK_RESET_NONE = 0,    /* traditional "false" value; still valid */
+	UNPACK_RESET_INVALID = 1, /* "true" no longer valid; use below values */
+	UNPACK_RESET_PROTECT_UNTRACKED,
+	UNPACK_RESET_OVERWRITE_UNTRACKED
+};
+
 struct unpack_trees_options {
-	unsigned int reset,
-		     merge,
+	unsigned int merge,
 		     update,
+		     preserve_ignored,
 		     clone,
 		     index_only,
 		     nontrivial_merge,
@@ -64,9 +71,9 @@
 		     exiting_early,
 		     show_all_errors,
 		     dry_run;
+	enum unpack_trees_reset_type reset;
 	const char *prefix;
 	int cache_bottom;
-	struct dir_struct *dir;
 	struct pathspec *pathspec;
 	merge_fn_t fn;
 	const char *msgs[NB_UNPACK_TREES_WARNING_TYPES];
@@ -88,6 +95,7 @@
 	struct index_state result;
 
 	struct pattern_list *pl; /* for internal use */
+	struct dir_struct *dir; /* for internal use only */
 	struct checkout_metadata meta;
 };
 
diff --git a/upload-pack.c b/upload-pack.c
index 6ce0723..c78d55b 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -1207,14 +1207,14 @@
 
 		format_symref_info(&symref_info, &data->symref);
 		format_session_id(&session_id, data);
-		packet_write_fmt(1, "%s %s%c%s%s%s%s%s%s%s object-format=%s agent=%s\n",
+		packet_fwrite_fmt(stdout, "%s %s%c%s%s%s%s%s%s%s object-format=%s agent=%s\n",
 			     oid_to_hex(oid), refname_nons,
 			     0, capabilities,
 			     (data->allow_uor & ALLOW_TIP_SHA1) ?
 				     " allow-tip-sha1-in-want" : "",
 			     (data->allow_uor & ALLOW_REACHABLE_SHA1) ?
 				     " allow-reachable-sha1-in-want" : "",
-			     data->stateless_rpc ? " no-done" : "",
+			     data->no_done ? " no-done" : "",
 			     symref_info.buf,
 			     data->allow_filter ? " filter" : "",
 			     session_id.buf,
@@ -1223,11 +1223,11 @@
 		strbuf_release(&symref_info);
 		strbuf_release(&session_id);
 	} else {
-		packet_write_fmt(1, "%s %s\n", oid_to_hex(oid), refname_nons);
+		packet_fwrite_fmt(stdout, "%s %s\n", oid_to_hex(oid), refname_nons);
 	}
 	capabilities = NULL;
 	if (!peel_iterated_oid(oid, &peeled))
-		packet_write_fmt(1, "%s %s^{}\n", oid_to_hex(&peeled), refname_nons);
+		packet_fwrite_fmt(stdout, "%s %s^{}\n", oid_to_hex(&peeled), refname_nons);
 	return 0;
 }
 
@@ -1329,7 +1329,8 @@
 	return parse_hide_refs_config(var, value, "uploadpack");
 }
 
-void upload_pack(struct upload_pack_options *options)
+void upload_pack(const int advertise_refs, const int stateless_rpc,
+		 const int timeout)
 {
 	struct packet_reader reader;
 	struct upload_pack_data data;
@@ -1338,16 +1339,24 @@
 
 	git_config(upload_pack_config, &data);
 
-	data.stateless_rpc = options->stateless_rpc;
-	data.daemon_mode = options->daemon_mode;
-	data.timeout = options->timeout;
+	data.stateless_rpc = stateless_rpc;
+	data.timeout = timeout;
+	if (data.timeout)
+		data.daemon_mode = 1;
 
 	head_ref_namespaced(find_symref, &data.symref);
 
-	if (options->advertise_refs || !data.stateless_rpc) {
+	if (advertise_refs || !data.stateless_rpc) {
 		reset_timeout(data.timeout);
+		if (advertise_refs)
+			data.no_done = 1;
 		head_ref_namespaced(send_ref, &data);
 		for_each_namespaced_ref(send_ref, &data);
+		/*
+		 * fflush stdout before calling advertise_shallow_grafts because send_ref
+		 * uses stdio.
+		 */
+		fflush_or_die(stdout);
 		advertise_shallow_grafts(1);
 		packet_flush(1);
 	} else {
@@ -1355,7 +1364,7 @@
 		for_each_namespaced_ref(check_ref, NULL);
 	}
 
-	if (!options->advertise_refs) {
+	if (!advertise_refs) {
 		packet_reader_init(&reader, 0, NULL, 0,
 				   PACKET_READ_CHOMP_NEWLINE |
 				   PACKET_READ_DIE_ON_ERR_PACKET);
@@ -1659,8 +1668,7 @@
 	FETCH_DONE,
 };
 
-int upload_pack_v2(struct repository *r, struct strvec *keys,
-		   struct packet_reader *request)
+int upload_pack_v2(struct repository *r, struct packet_reader *request)
 {
 	enum fetch_state state = FETCH_PROCESS_ARGS;
 	struct upload_pack_data data;
diff --git a/upload-pack.h b/upload-pack.h
index 27ddcdc..d6ee25e 100644
--- a/upload-pack.h
+++ b/upload-pack.h
@@ -1,20 +1,12 @@
 #ifndef UPLOAD_PACK_H
 #define UPLOAD_PACK_H
 
-struct upload_pack_options {
-	int stateless_rpc;
-	int advertise_refs;
-	unsigned int timeout;
-	int daemon_mode;
-};
-
-void upload_pack(struct upload_pack_options *options);
+void upload_pack(const int advertise_refs, const int stateless_rpc,
+		 const int timeout);
 
 struct repository;
-struct strvec;
 struct packet_reader;
-int upload_pack_v2(struct repository *r, struct strvec *keys,
-		   struct packet_reader *request);
+int upload_pack_v2(struct repository *r, struct packet_reader *request);
 
 struct strbuf;
 int upload_pack_advertise(struct repository *r,
diff --git a/urlmatch.h b/urlmatch.h
index 6ff42f8..34a3ba6 100644
--- a/urlmatch.h
+++ b/urlmatch.h
@@ -66,6 +66,10 @@
 	int (*fallback_match_fn)(const char *url, void *cb);
 };
 
+#define URLMATCH_CONFIG_INIT { \
+	.vars = STRING_LIST_INIT_DUP, \
+}
+
 int urlmatch_config_entry(const char *var, const char *value, void *cb);
 
 #endif /* URL_MATCH_H */
diff --git a/userdiff.c b/userdiff.c
index d9b2ba7..8578cb0 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -13,6 +13,16 @@
 #define IPATTERN(name, pattern, word_regex)			\
 	{ name, NULL, -1, { pattern, REG_EXTENDED | REG_ICASE }, \
 	  word_regex "|[^[:space:]]|[\xc0-\xff][\x80-\xbf]+" }
+
+/*
+ * Built-in drivers for various languages, sorted by their names
+ * (except that the "default" is left at the end).
+ *
+ * When writing or updating patterns, assume that the contents these
+ * patterns are applied to are syntactically correct.  The patterns
+ * can be simple without implementing all syntactical corner cases, as
+ * long as they are sufficiently permissive.
+ */
 static struct userdiff_driver builtin_drivers[] = {
 IPATTERN("ada",
 	 "!^(.*[ \t])?(is[ \t]+new|renames|is[ \t]+separate)([ \t].*)?$\n"
@@ -54,9 +64,15 @@
 	 /* functions/methods, variables, and compounds at top level */
 	 "^((::[[:space:]]*)?[A-Za-z_].*)$",
 	 /* -- */
+	 /* identifiers and keywords */
 	 "[a-zA-Z_][a-zA-Z0-9_]*"
-	 "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lLuU]*"
-	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->\\*?|\\.\\*"),
+	 /* decimal and octal integers as well as floatingpoint numbers */
+	 "|[0-9][0-9.]*([Ee][-+]?[0-9]+)?[fFlLuU]*"
+	 /* hexadecimal and binary integers */
+	 "|0[xXbB][0-9a-fA-F]+[lLuU]*"
+	 /* floatingpoint numbers that begin with a decimal point */
+	 "|\\.[0-9][0-9]*([Ee][-+]?[0-9]+)?[fFlL]?"
+	 "|[-+*/<>%&^|=!]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\||::|->\\*?|\\.\\*|<=>"),
 PATTERNS("csharp",
 	 /* Keywords */
 	 "!^[ \t]*(do|while|for|if|else|instanceof|new|return|switch|case|throw|catch|using)\n"
@@ -142,7 +158,11 @@
 	 "[^<>= \t]+"),
 PATTERNS("java",
 	 "!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n"
-	 "^[ \t]*(([A-Za-z_][A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$",
+	 /* Class, enum, and interface declarations */
+	 "^[ \t]*(([a-z]+[ \t]+)*(class|enum|interface)[ \t]+[A-Za-z][A-Za-z0-9_$]*[ \t]+.*)$\n"
+	 /* Method definitions; note that constructor signatures are not */
+	 /* matched because they are indistinguishable from method calls. */
+	 "^[ \t]*(([A-Za-z_<>&][][?&<>.,A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)$",
 	 /* -- */
 	 "[a-zA-Z_][a-zA-Z0-9_]*"
 	 "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
@@ -214,7 +234,7 @@
 	 "|<<|<>|<=>|>>"),
 PATTERNS("php",
 	 "^[\t ]*(((public|protected|private|static|abstract|final)[\t ]+)*function.*)$\n"
-	 "^[\t ]*((((final|abstract)[\t ]+)?class|interface|trait).*)$",
+	 "^[\t ]*((((final|abstract)[\t ]+)?class|enum|interface|trait).*)$",
 	 /* -- */
 	 "[a-zA-Z_][a-zA-Z0-9_]*"
 	 "|[-+0-9.e]+|0[xXbB]?[0-9a-fA-F]+"
diff --git a/wrapper.c b/wrapper.c
index 7c6586a..36e1211 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -145,6 +145,12 @@
 	return ret;
 }
 
+void xsetenv(const char *name, const char *value, int overwrite)
+{
+	if (setenv(name, value, overwrite))
+		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
diff --git a/write-or-die.c b/write-or-die.c
index d33e68f..0b1ec81 100644
--- a/write-or-die.c
+++ b/write-or-die.c
@@ -70,3 +70,15 @@
 		die_errno("write error");
 	}
 }
+
+void fwrite_or_die(FILE *f, const void *buf, size_t count)
+{
+	if (fwrite(buf, 1, count, f) != count)
+		die_errno("fwrite error");
+}
+
+void fflush_or_die(FILE *f)
+{
+	if (fflush(f))
+		die_errno("fflush error");
+}
diff --git a/wt-status.c b/wt-status.c
index eaed30e..e4f29b2 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -787,7 +787,7 @@
 
 	dir_clear(&dir);
 
-	if (advice_status_u_option)
+	if (advice_enabled(ADVICE_STATUS_U_OPTION))
 		s->untracked_in_ms = (getnanotime() - t_begin) / 1000000;
 }
 
@@ -1158,7 +1158,7 @@
 	if (!format_tracking_info(branch, &sb, s->ahead_behind_flags))
 		return;
 
-	if (advice_status_ahead_behind_warning &&
+	if (advice_enabled(ADVICE_STATUS_AHEAD_BEHIND_WARNING) &&
 	    s->ahead_behind_flags == AHEAD_BEHIND_FULL) {
 		uint64_t t_delta_in_ms = (getnanotime() - t_begin) / 1000000;
 		if (t_delta_in_ms > AB_DELAY_WARNING_IN_MS) {
@@ -1845,7 +1845,7 @@
 		wt_longstatus_print_other(s, &s->untracked, _("Untracked files"), "add");
 		if (s->show_ignored_mode)
 			wt_longstatus_print_other(s, &s->ignored, _("Ignored files"), "add -f");
-		if (advice_status_u_option && 2000 < s->untracked_in_ms) {
+		if (advice_enabled(ADVICE_STATUS_U_OPTION) && 2000 < s->untracked_in_ms) {
 			status_printf_ln(s, GIT_COLOR_NORMAL, "%s", "");
 			status_printf_ln(s, GIT_COLOR_NORMAL,
 					 _("It took %.2f seconds to enumerate untracked files. 'status -uno'\n"