diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 44e0fe5..3042540 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -7,34 +7,34 @@
 
 jobs:
   ci-config:
-      runs-on: ubuntu-latest
-      outputs:
-        enabled: ${{ steps.check-ref.outputs.enabled }}
-      steps:
-        - name: try to clone ci-config branch
-          continue-on-error: true
-          run: |
-            git -c protocol.version=2 clone \
-              --no-tags \
-              --single-branch \
-              -b ci-config \
-              --depth 1 \
-              --no-checkout \
-              --filter=blob:none \
-              https://github.com/${{ github.repository }} \
-              config-repo &&
-              cd config-repo &&
-              git checkout HEAD -- ci/config
-        - id: check-ref
-          name: check whether CI is enabled for ref
-          run: |
-            enabled=yes
-            if test -x config-repo/ci/config/allow-ref &&
-               ! config-repo/ci/config/allow-ref '${{ github.ref }}'
-            then
-              enabled=no
-            fi
-            echo "::set-output name=enabled::$enabled"
+    runs-on: ubuntu-latest
+    outputs:
+      enabled: ${{ steps.check-ref.outputs.enabled }}
+    steps:
+      - name: try to clone ci-config branch
+        continue-on-error: true
+        run: |
+          git -c protocol.version=2 clone \
+            --no-tags \
+            --single-branch \
+            -b ci-config \
+            --depth 1 \
+            --no-checkout \
+            --filter=blob:none \
+            https://github.com/${{ github.repository }} \
+            config-repo &&
+            cd config-repo &&
+            git checkout HEAD -- ci/config
+      - id: check-ref
+        name: check whether CI is enabled for ref
+        run: |
+          enabled=yes
+          if test -x config-repo/ci/config/allow-ref &&
+             ! config-repo/ci/config/allow-ref '${{ github.ref }}'
+          then
+            enabled=no
+          fi
+          echo "::set-output name=enabled::$enabled"
 
   windows-build:
     needs: ci-config
diff --git a/Documentation/MyFirstContribution.txt b/Documentation/MyFirstContribution.txt
index d85c9b5..4f85a08 100644
--- a/Documentation/MyFirstContribution.txt
+++ b/Documentation/MyFirstContribution.txt
@@ -319,14 +319,14 @@
 ...
 
 	git_config(git_default_config, NULL);
-	if (git_config_get_string_const("user.name", &cfg_name) > 0)
+	if (git_config_get_string_tmp("user.name", &cfg_name) > 0)
 		printf(_("No name is found in config\n"));
 	else
 		printf(_("Your name: %s\n"), cfg_name);
 ----
 
 `git_config()` will grab the configuration from config files known to Git and
-apply standard precedence rules. `git_config_get_string_const()` will look up
+apply standard precedence rules. `git_config_get_string_tmp()` will look up
 a specific key ("user.name") and give you the value. There are a number of
 single-key lookup functions like this one; you can see them all (and more info
 about how to use `git_config()`) in `Documentation/technical/api-config.txt`.
diff --git a/Documentation/RelNotes/2.29.0.txt b/Documentation/RelNotes/2.29.0.txt
index 483ebb4..a020dad 100644
--- a/Documentation/RelNotes/2.29.0.txt
+++ b/Documentation/RelNotes/2.29.0.txt
@@ -19,6 +19,42 @@
    configurable to selectively allow or reject object filtering
    specification used for partial cloning.
 
+ * Stop when "sendmail.*" configuration variables are defined, which
+   could be a mistaken attempt to define "sendemail.*" variables.
+
+ * The existing backends for "git mergetool" based on variants of vim
+   have been refactored and then support for "nvim" has been added.
+
+ * "git bisect" learns the "--first-parent" option to find the first
+   breakage along the first-parent chain.
+
+ * "git log --first-parent -p" showed patches only for single-parent
+   commits on the first-parent chain; the "--first-parent" option has
+   been made to imply "-m".  Use "--no-diff-merges" to restore the
+   previous behaviour to omit patches for merge commits.
+
+ * The commit labels used to explain each side of conflicted hunks
+   placed by the sequencer machinery have been made more readable by
+   humans.
+
+ * The "--batch-size" option of "git multi-pack-index repack" command
+   is now used to specify that very small packfiles are collected into
+   one until the total size roughly exceeds it.
+
+ * The recent addition of SHA-256 support is marked as experimental in
+   the documentation.
+
+ * "git fetch" learned --no-write-fetch-head option to avoid writing
+   the FETCH_HEAD file.
+
+ * Command line completion (in contrib/) usually omits redundant,
+   deprecated and/or dangerous options from its output; it learned to
+   optionally include all of them.
+
+ * The output from the "diff" family of the commands had abbreviated
+   object names of blobs involved in the patch, but its length was not
+   affected by the --abbrev option.  Now it is.
+
 
 Performance, Internal Implementation, Development Support etc.
 
@@ -52,7 +88,9 @@
    to a certain degree.  It has been renamed to "strvec" to reduce the
    barrier to adoption.
 
- * The final leg of SHA-256 transition.
+ * The final leg of SHA-256 transition plus doc updates.  Note that
+   there is no inter-operability between SHA-1 and SHA-256
+   repositories yet.
 
  * CMake support to build with MSVC for Windows bypassing the Makefile.
 
@@ -60,6 +98,29 @@
    easier to mark object existence checks that do and don't want to
    trigger lazy fetches, and a few such checks are converted using it.
 
+ * A no-op replacement function implemented as a C preprocessor macro
+   does not perform as good a job as one implemented as a "static
+   inline" function in catching errors in parameters; replace the
+   former with the latter in <git-compat-util.h> header.
+
+ * Test framework update.
+   (merge d572f52a64 es/test-cmp-typocatcher later to maint).
+
+ * Updates to "git merge" tests, in preparation for a new merge
+   strategy backend.
+
+ * midx and commit-graph files now use the byte defined in their file
+   format specification for identifying the hash function used for
+   object names.
+
+ * The FETCH_HEAD is now always read from the filesystem regardless of
+   the ref backend in use, as its format is much richer than the
+   normal refs, and written directly by "git fetch" as a plain file..
+
+ * A handful of places in in-tree code still relied on being able to
+   execute the git subcommands, especially built-ins, in "git-foo"
+   form, which have been corrected.
+
 
 Fixes since v2.28
 -----------------
@@ -110,6 +171,98 @@
    it is.
    (merge 11bc12ae1e rp/blame-first-parent-doc later to maint).
 
+ * The logic to find the ref transaction hook script attempted to
+   cache the path to the found hook without realizing that it needed
+   to keep a copied value, as the API it used returned a transitory
+   buffer space.  This has been corrected.
+   (merge 09b2aa30c9 ps/ref-transaction-hook later to maint).
+
+ * Recent versions of "git diff-files" shows a diff between the index
+   and the working tree for "intent-to-add" paths as a "new file"
+   patch; "git apply --cached" should be able to take "git diff-files"
+   and should act as an equivalent to "git add" for the path, but the
+   command failed to do so for such a path.
+   (merge 4c025c667e rp/apply-cached-with-i-t-a later to maint).
+
+ * "git diff [<tree-ish>] $path" for a $path that is marked with i-t-a
+   bit was not showing the mode bits from the working tree.
+   (merge cb0dd22b82 rp/ita-diff-modefix later to maint).
+
+ * Ring buffer with size 4 used for bin-hex translation resulted in a
+   wrong object name in the sequencer's todo output, which has been
+   corrected.
+   (merge 5da69c0dac ak/sequencer-fix-find-uniq-abbrev later to maint).
+
+ * When given more than one target line ranges, "git blame -La,b
+   -Lc,d" was over-eager to coalesce groups of original lines and
+   showed incorrect results, which has been corrected.
+   (merge c2ebaa27d6 jk/blame-coalesce-fix later to maint).
+
+ * The regexp to identify the function boundary for FORTRAN programs
+   has been updated.
+   (merge 75c3b6b2e8 pb/userdiff-fortran-update later to maint).
+
+ * A few end-user facing messages have been updated to be
+   hash-algorithm agnostic.
+   (merge 4279000d3e jc/object-names-are-not-sha-1 later to maint).
+
+ * "unlink" emulation on MinGW has been optimized.
+   (merge 680e0b4524 jh/mingw-unlink later to maint).
+
+ * The purpose of "git init --separate-git-dir" is to initialize a
+   new project with the repository separate from the working tree,
+   or, in the case of an existing project, to move the repository
+   (the .git/ directory) out of the working tree. It does not make
+   sense to use --separate-git-dir with a bare repository for which
+   there is no working tree, so disallow its use with bare
+   repositories.
+   (merge ccf236a23a es/init-no-separate-git-dir-in-bare later to maint).
+
+ * "ls-files -o" mishandled the top-level directory of another git
+   working tree that hangs in the current git working tree.
+   (merge ab282aa548 en/dir-nonbare-embedded later to maint).
+
+ * Fix some incorrect UNLEAK() annotations.
+   (merge 3e19816dc0 jk/unleak-fixes later to maint).
+
+ * Use more buffered I/O where we used to call many small write(2)s.
+   (merge a698d67b08 rs/more-buffered-io later to maint).
+
+ * The patch-id computation did not ignore the "incomplete last line"
+   marker like whitespaces.
+   (merge 82a62015a7 rs/patch-id-with-incomplete-line later to maint).
+
+ * Updates into a lazy/partial clone with a submodule did not work
+   well with transfer.fsckobjects set.
+
+ * The parser for "git for-each-ref --format=..." was too loose when
+   parsing the "%(trailers...)" atom, and forgot that "trailers" and
+   "trailers:<modifiers>" are the only two allowed forms, which has
+   been corrected.
+   (merge 2c22e102f8 hv/ref-filter-trailers-atom-parsing-fix later to maint).
+
+ * Long ago, we decided to use 3 threads by default when running the
+   index-pack task in parallel, which has been adjusted a bit upwards.
+   (merge fbff95b67f jk/index-pack-w-more-threads later to maint).
+
+ * "git restore/checkout --no-overlay" with wildcarded pathspec
+   mistakenly removed matching paths in subdirectories, which has been
+   corrected.
+   (merge bfda204ade rs/checkout-no-overlay-pathspec-fix later to maint).
+
+ * The description of --cached/--index options in "git apply --help"
+   has been updated.
+   (merge d064702be3 rp/apply-cached-doc later to maint).
+
+ * Feeding "$ZERO_OID" to "git log --ignore-missing --stdin", and
+   running "git log --ignore-missing $ZERO_OID" fell back to start
+   digging from HEAD; it has been corrected to become a no-op, like
+   "git log --tags=no-tag-matches-this-pattern" does.
+   (merge 04a0e98515 jk/rev-input-given-fix later to maint).
+
+ * Various callers of run_command API has been modernized.
+   (merge afbdba391e jc/run-command-use-embedded-args later to maint).
+
  * Other code cleanup, docfix, build fix, etc.
    (merge 84544f2ea3 sk/typofixes later to maint).
    (merge b17f411ab5 ar/help-guides-doc later to maint).
@@ -124,3 +277,11 @@
    (merge de20baf2c9 ny/notes-doc-sample-update later to maint).
    (merge f649aaaf82 so/rev-parser-errormessage-fix later to maint).
    (merge 6103d58b7f bc/sha-256-cvs-svn-updates later to maint).
+   (merge ac900fddb7 ma/stop-progress-null-fix later to maint).
+   (merge e767963ab6 rs/upload-pack-sigchain-fix later to maint).
+   (merge a831908599 rs/preserve-merges-unused-code-removal later to maint).
+   (merge 6dfefe70a9 jb/commit-graph-doc-fix later to maint).
+   (merge 847b37271e pb/set-url-docfix later to maint).
+   (merge 748f733d54 mt/checkout-entry-dead-code-removal later to maint).
+   (merge ce820cbd58 dl/subtree-docs later to maint).
+   (merge 55fe225dde jk/leakfix later to maint).
diff --git a/Documentation/config/sendemail.txt b/Documentation/config/sendemail.txt
index 0006faf..cbc5af4 100644
--- a/Documentation/config/sendemail.txt
+++ b/Documentation/config/sendemail.txt
@@ -61,3 +61,8 @@
 sendemail.smtpReloginDelay::
 	Seconds wait before reconnecting to smtp server.
 	See also the `--relogin-delay` option of linkgit:git-send-email[1].
+
+sendemail.forbidSendmailVariables::
+	To avoid common misconfiguration mistakes, linkgit:git-send-email[1]
+	will abort with a warning if any configuration options for "sendmail"
+	exist. Set this variable to bypass the check.
diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 7987d72..573fb9b 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -73,6 +73,11 @@
 	Synonym for `-p --raw`.
 endif::git-format-patch[]
 
+ifdef::git-log[]
+-t::
+	Show the tree objects in the diff output.
+endif::git-log[]
+
 --indent-heuristic::
 	Enable the heuristic that shifts diff hunk boundaries to make patches
 	easier to read. This is the default.
@@ -441,10 +446,11 @@
 --abbrev[=<n>]::
 	Instead of showing the full 40-byte hexadecimal object
 	name in diff-raw format output and diff-tree header
-	lines, show only a partial prefix.  This is
-	independent of the `--full-index` option above, which controls
-	the diff-patch output format.  Non default number of
-	digits can be specified with `--abbrev=<n>`.
+	lines, show only a partial prefix.
+	In diff-patch output format, `--full-index` takes higher
+	precedence, i.e. if `--full-index` is specified, full blob
+	names will be shown regardless of `--abbrev`.
+	Non default number of digits can be specified with `--abbrev=<n>`.
 
 -B[<n>][/<m>]::
 --break-rewrites[=[<n>][/<m>]]::
diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt
index 6e2a160..e8104c0 100644
--- a/Documentation/fetch-options.txt
+++ b/Documentation/fetch-options.txt
@@ -64,6 +64,15 @@
 --dry-run::
 	Show what would be done, without making any changes.
 
+ifndef::git-pull[]
+--[no-]write-fetch-head::
+	Write the list of remote refs fetched in the `FETCH_HEAD`
+	file directly under `$GIT_DIR`.  This is the default.
+	Passing `--no-write-fetch-head` from the command line tells
+	Git not to write the file.  Under `--dry-run` option, the
+	file is never written.
+endif::git-pull[]
+
 -f::
 --force::
 	When 'git fetch' is used with `<src>:<dst>` refspec it may
@@ -186,7 +195,7 @@
 endif::git-pull[]
 
 --set-upstream::
-	If the remote is fetched successfully, pull and add upstream
+	If the remote is fetched successfully, add upstream
 	(tracking) reference, used by argument-less
 	linkgit:git-pull[1] and other commands. For more information,
 	see `branch.<name>.merge` and `branch.<name>.remote` in
diff --git a/Documentation/git-apply.txt b/Documentation/git-apply.txt
index b9aa390..91d9a86 100644
--- a/Documentation/git-apply.txt
+++ b/Documentation/git-apply.txt
@@ -61,18 +61,18 @@
 	file and detects errors.  Turns off "apply".
 
 --index::
-	When `--check` is in effect, or when applying the patch
-	(which is the default when none of the options that
-	disables it is in effect), make sure the patch is
-	applicable to what the current index file records.  If
-	the file to be patched in the working tree is not
-	up to date, it is flagged as an error.  This flag also
-	causes the index file to be updated.
+	Apply the patch to both the index and the working tree (or
+	merely check that it would apply cleanly to both if `--check` is
+	in effect). Note that `--index` expects index entries and
+	working tree copies for relevant paths to be identical (their
+	contents and metadata such as file mode must match), and will
+	raise an error if they are not, even if the patch would apply
+	cleanly to both the index and the working tree in isolation.
 
 --cached::
-	Apply a patch without touching the working tree. Instead take the
-	cached data, apply the patch, and store the result in the index
-	without using the working tree. This implies `--index`.
+	Apply the patch to just the index, without touching the working
+	tree. If `--check` is in effect, merely check that it would
+	apply cleanly to the index entry.
 
 --intent-to-add::
 	When applying the patch only to the working tree, mark new
diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt
index 7586c5a..0e993e4 100644
--- a/Documentation/git-bisect.txt
+++ b/Documentation/git-bisect.txt
@@ -17,7 +17,7 @@
 on the subcommand:
 
  git bisect start [--term-{old,good}=<term> --term-{new,bad}=<term>]
-		  [--no-checkout] [<bad> [<good>...]] [--] [<paths>...]
+		  [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]
  git bisect (bad|new|<term-new>) [<rev>]
  git bisect (good|old|<term-old>) [<rev>...]
  git bisect terms [--term-good | --term-bad]
@@ -365,6 +365,17 @@
 +
 If the repository is bare, `--no-checkout` is assumed.
 
+--first-parent::
++
+Follow only the first parent commit upon seeing a merge commit.
++
+In detecting regressions introduced through the merging of a branch, the merge
+commit will be identified as introduction of the bug and its ancestors will be
+ignored.
++
+This option is particularly useful in avoiding false positives when a merged
+branch contained broken or non-buildable commits, but the merge itself was OK.
+
 EXAMPLES
 --------
 
diff --git a/Documentation/git-index-pack.txt b/Documentation/git-index-pack.txt
index ac74d05..af0c262 100644
--- a/Documentation/git-index-pack.txt
+++ b/Documentation/git-index-pack.txt
@@ -100,6 +100,8 @@
 	value is set or outside a repository.
 +
 This option cannot be used with --stdin.
++
+include::object-format-disclaimer.txt[]
 
 NOTES
 -----
diff --git a/Documentation/git-init.txt b/Documentation/git-init.txt
index ddfe265..f35f70f 100644
--- a/Documentation/git-init.txt
+++ b/Documentation/git-init.txt
@@ -53,6 +53,8 @@
 
 Specify the given object format (hash algorithm) for the repository.  The valid
 values are 'sha1' and (if enabled) 'sha256'.  'sha1' is the default.
++
+include::object-format-disclaimer.txt[]
 
 --template=<template_directory>::
 
diff --git a/Documentation/git-log.txt b/Documentation/git-log.txt
index 3fd26d5..2b8ac5f 100644
--- a/Documentation/git-log.txt
+++ b/Documentation/git-log.txt
@@ -114,8 +114,51 @@
 
 include::pretty-formats.txt[]
 
-COMMON DIFF OPTIONS
--------------------
+DIFF FORMATTING
+---------------
+
+By default, `git log` does not generate any diff output. The options
+below can be used to show the changes made by each commit.
+
+Note that unless one of `-c`, `--cc`, or `-m` is given, merge commits
+will never show a diff, even if a diff format like `--patch` is
+selected, nor will they match search options like `-S`. The exception is
+when `--first-parent` is in use, in which merges are treated like normal
+single-parent commits (this can be overridden by providing a
+combined-diff option or with `--no-diff-merges`).
+
+-c::
+	With this option, diff output for a merge commit
+	shows the differences from each of the parents to the merge result
+	simultaneously instead of showing pairwise diff between a parent
+	and the result one at a time. Furthermore, it lists only files
+	which were modified from all parents.
+
+--cc::
+	This flag implies the `-c` option and further compresses the
+	patch output by omitting uninteresting hunks whose contents in
+	the parents have only two variants and the merge result picks
+	one of them without modification.
+
+--combined-all-paths::
+	This flag causes combined diffs (used for merge commits) to
+	list the name of the file from all parents.  It thus only has
+	effect when -c or --cc are specified, and is likely only
+	useful if filename changes are detected (i.e. when either
+	rename or copy detection have been requested).
+
+-m::
+	This flag makes the merge commits show the full diff like
+	regular commits; for each merge parent, a separate log entry
+	and diff is generated. An exception is that only diff against
+	the first parent is shown when `--first-parent` option is given;
+	in that case, the output represents the changes the merge
+	brought _into_ the then-current branch.
+
+--diff-merges=off::
+--no-diff-merges::
+	Disable output of diffs for merge commits (default). Useful to
+	override `-m`, `-c`, or `--cc`.
 
 :git-log: 1
 include::diff-options.txt[]
diff --git a/Documentation/git-multi-pack-index.txt b/Documentation/git-multi-pack-index.txt
index 0c66194..eb0caa0 100644
--- a/Documentation/git-multi-pack-index.txt
+++ b/Documentation/git-multi-pack-index.txt
@@ -51,11 +51,12 @@
 	multi-pack-index, then divide by the total number of objects in
 	the pack and multiply by the pack size. We select packs with
 	expected size below the batch size until the set of packs have
-	total expected size at least the batch size. If the total size
-	does not reach the batch size, then do nothing. If a new pack-
-	file is created, rewrite the multi-pack-index to reference the
-	new pack-file. A later run of 'git multi-pack-index expire' will
-	delete the pack-files that were part of this batch.
+	total expected size at least the batch size, or all pack-files
+	are considered. If only one pack-file is selected, then do
+	nothing. If a new pack-file is created, rewrite the
+	multi-pack-index to reference the new pack-file. A later run of
+	'git multi-pack-index expire' will delete the pack-files that
+	were part of this batch.
 +
 If `repack.packKeptObjects` is `false`, then any pack-files with an
 associated `.keep` file will not be selected for the batch to repack.
diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index 374d248..e8df8d5 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -459,17 +459,38 @@
 See also INCOMPATIBLE OPTIONS below.
 
 --ignore-whitespace::
+	Ignore whitespace differences when trying to reconcile
+differences. Currently, each backend implements an approximation of
+this behavior:
++
+apply backend: When applying a patch, ignore changes in whitespace in
+context lines. Unfortunately, this means that if the "old" lines being
+replaced by the patch differ only in whitespace from the existing
+file, you will get a merge conflict instead of a successful patch
+application.
++
+merge backend: Treat lines with only whitespace changes as unchanged
+when merging. Unfortunately, this means that any patch hunks that were
+intended to modify whitespace and nothing else will be dropped, even
+if the other side had no changes that conflicted.
+
 --whitespace=<option>::
-	These flags are passed to the 'git apply' program
+	This flag is passed to the 'git apply' program
 	(see linkgit:git-apply[1]) that applies the patch.
 	Implies --apply.
 +
 See also INCOMPATIBLE OPTIONS below.
 
 --committer-date-is-author-date::
+	Instead of using the current time as the committer date, use
+	the author date of the commit being rebased as the committer
+	date. This option implies `--force-rebase`.
+
 --ignore-date::
-	These flags are passed to 'git am' to easily change the dates
-	of the rebased commits (see linkgit:git-am[1]).
+--reset-author-date::
+	Instead of using the author date of the original commit, use
+	the current time as the	author date of the rebased commit.  This
+	option implies `--force-rebase`.
 +
 See also INCOMPATIBLE OPTIONS below.
 
@@ -607,9 +628,6 @@
 The following options:
 
  * --apply
- * --committer-date-is-author-date
- * --ignore-date
- * --ignore-whitespace
  * --whitespace
  * -C
 
@@ -636,6 +654,9 @@
  * --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
diff --git a/Documentation/git-show-index.txt b/Documentation/git-show-index.txt
index 39b1d8e..e49318a 100644
--- a/Documentation/git-show-index.txt
+++ b/Documentation/git-show-index.txt
@@ -44,6 +44,8 @@
 	valid values are 'sha1' and (if enabled) 'sha256'.  The default is the
 	algorithm for the current repository (set by `extensions.objectFormat`), or
 	'sha1' if no value is set or outside a repository..
++
+include::object-format-disclaimer.txt[]
 
 GIT
 ---
diff --git a/Documentation/git-update-ref.txt b/Documentation/git-update-ref.txt
index 3e737c2..d401234 100644
--- a/Documentation/git-update-ref.txt
+++ b/Documentation/git-update-ref.txt
@@ -148,12 +148,13 @@
 
 LOGGING UPDATES
 ---------------
-If config parameter "core.logAllRefUpdates" is true and the ref is one under
-"refs/heads/", "refs/remotes/", "refs/notes/", or the symbolic ref HEAD; or
-the file "$GIT_DIR/logs/<ref>" exists then `git update-ref` will append
-a line to the log file "$GIT_DIR/logs/<ref>" (dereferencing all
-symbolic refs before creating the log name) describing the change
-in ref value.  Log lines are formatted as:
+If config parameter "core.logAllRefUpdates" is true and the ref is one
+under "refs/heads/", "refs/remotes/", "refs/notes/", or a pseudoref
+like HEAD or ORIG_HEAD; or the file "$GIT_DIR/logs/<ref>" exists then
+`git update-ref` will append a line to the log file
+"$GIT_DIR/logs/<ref>" (dereferencing all symbolic refs before creating
+the log name) describing the change in ref value.  Log lines are
+formatted as:
 
     oldsha1 SP newsha1 SP committer LF
 
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 81349a8..2fc9258 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -504,7 +504,8 @@
 	If this variable is set, the default hash algorithm for new
 	repositories will be set to this value. This value is currently
 	ignored when cloning; the setting of the remote repository
-	is used instead. The default is "sha1".
+	is used instead. The default is "sha1". THIS VARIABLE IS
+	EXPERIMENTAL! See `--object-format` in linkgit:git-init[1].
 
 Git Commits
 ~~~~~~~~~~~
diff --git a/Documentation/object-format-disclaimer.txt b/Documentation/object-format-disclaimer.txt
new file mode 100644
index 0000000..4cb106f
--- /dev/null
+++ b/Documentation/object-format-disclaimer.txt
@@ -0,0 +1,6 @@
+THIS OPTION IS EXPERIMENTAL! SHA-256 support is experimental and still
+in an early stage.  A SHA-256 repository will in general not be able to
+share work with "regular" SHA-1 repositories.  It should be assumed
+that, e.g., Git internal file formats in relation to SHA-256
+repositories may change in backwards-incompatible ways.  Only use
+`--object-format=sha256` for testing purposes.
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index b01b2b6..0023790 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -128,8 +128,7 @@
 	because merges into a topic branch tend to be only about
 	adjusting to updated upstream from time to time, and
 	this option allows you to ignore the individual commits
-	brought in to your history by such a merge. Cannot be
-	combined with --bisect.
+	brought in to your history by such a merge.
 
 --not::
 	Reverses the meaning of the '{caret}' prefix (or lack thereof)
@@ -207,7 +206,7 @@
 	Pretend as if the bad bisection ref `refs/bisect/bad`
 	was listed and as if it was followed by `--not` and the good
 	bisection refs `refs/bisect/good-*` on the command
-	line. Cannot be combined with --first-parent.
+	line.
 endif::git-rev-list[]
 
 --stdin::
@@ -743,7 +742,7 @@
 would be of roughly the same length.  Finding the change which
 introduces a regression is thus reduced to a binary search: repeatedly
 generate and test new 'midpoint's until the commit chain is of length
-one. Cannot be combined with --first-parent.
+one.
 
 --bisect-vars::
 	This calculates the same as `--bisect`, except that refs in
@@ -1117,48 +1116,3 @@
 	by a tab.
 endif::git-rev-list[]
 endif::git-shortlog[]
-
-ifndef::git-shortlog[]
-ifndef::git-rev-list[]
-Diff Formatting
-~~~~~~~~~~~~~~~
-
-Listed below are options that control the formatting of diff output.
-Some of them are specific to linkgit:git-rev-list[1], however other diff
-options may be given. See linkgit:git-diff-files[1] for more options.
-
--c::
-	With this option, diff output for a merge commit
-	shows the differences from each of the parents to the merge result
-	simultaneously instead of showing pairwise diff between a parent
-	and the result one at a time. Furthermore, it lists only files
-	which were modified from all parents.
-
---cc::
-	This flag implies the `-c` option and further compresses the
-	patch output by omitting uninteresting hunks whose contents in
-	the parents have only two variants and the merge result picks
-	one of them without modification.
-
---combined-all-paths::
-	This flag causes combined diffs (used for merge commits) to
-	list the name of the file from all parents.  It thus only has
-	effect when -c or --cc are specified, and is likely only
-	useful if filename changes are detected (i.e. when either
-	rename or copy detection have been requested).
-
--m::
-	This flag makes the merge commits show the full diff like
-	regular commits; for each merge parent, a separate log entry
-	and diff is generated. An exception is that only diff against
-	the first parent is shown when `--first-parent` option is given;
-	in that case, the output represents the changes the merge
-	brought _into_ the then-current branch.
-
--r::
-	Show recursive diffs.
-
--t::
-	Show the tree objects in the diff output. This implies `-r`.
-endif::git-rev-list[]
-endif::git-shortlog[]
diff --git a/Documentation/technical/commit-graph-format.txt b/Documentation/technical/commit-graph-format.txt
index 4405410..6ddbceb 100644
--- a/Documentation/technical/commit-graph-format.txt
+++ b/Documentation/technical/commit-graph-format.txt
@@ -42,8 +42,13 @@
   1-byte version number:
       Currently, the only valid version is 1.
 
-  1-byte Hash Version (1 = SHA-1)
-      We infer the hash length (H) from this value.
+  1-byte Hash Version
+      We infer the hash length (H) from this value:
+	1 => SHA-1
+	2 => SHA-256
+      If the hash type does not match the repository's hash algorithm, the
+      commit-graph file should be ignored with a warning presented to the
+      user.
 
   1-byte number (C) of "chunks"
 
diff --git a/Documentation/technical/commit-graph.txt b/Documentation/technical/commit-graph.txt
index 808fa30..f14a765 100644
--- a/Documentation/technical/commit-graph.txt
+++ b/Documentation/technical/commit-graph.txt
@@ -210,12 +210,12 @@
 			    +---------------------+
 			    |                     |
  +-----------------------+  +---------------------+
- |  graph-{hash2} |->|                     |
+ |  graph-{hash2}        |->|                     |
  +-----------------------+  +---------------------+
 	  |                 |                     |
  +-----------------------+  +---------------------+
  |                       |  |                     |
- |  graph-{hash1} |->|                     |
+ |  graph-{hash1}        |->|                     |
  |                       |  |                     |
  +-----------------------+  +---------------------+
 	  |                  tmp_graphXXX
@@ -223,7 +223,7 @@
  |                       |
  |                       |
  |                       |
- |  graph-{hash0} |
+ |  graph-{hash0}        |
  |                       |
  |                       |
  |                       |
diff --git a/Documentation/technical/hash-function-transition.txt b/Documentation/technical/hash-function-transition.txt
index 5b2db3b..6fd20eb 100644
--- a/Documentation/technical/hash-function-transition.txt
+++ b/Documentation/technical/hash-function-transition.txt
@@ -650,7 +650,6 @@
 
 The first user-visible change is the introduction of the objectFormat
 extension (without compatObjectFormat). This requires:
-- implementing the loose-object-idx
 - teaching fsck about this mode of operation
 - using the hash function API (vtable) when computing object names
 - signing objects and verifying signatures
@@ -658,6 +657,7 @@
   repository
 
 Next comes introduction of compatObjectFormat:
+- implementing the loose-object-idx
 - translating object names between object formats
 - translating object content between object formats
 - generating and verifying signatures in the compat format
diff --git a/Documentation/technical/http-protocol.txt b/Documentation/technical/http-protocol.txt
index 51a79e6..96d89ea 100644
--- a/Documentation/technical/http-protocol.txt
+++ b/Documentation/technical/http-protocol.txt
@@ -401,8 +401,9 @@
 The stream is terminated by a pkt-line flush (`0000`).
 
 A single "want" or "have" command MUST have one hex formatted
-SHA-1 as its value.  Multiple SHA-1s MUST be sent by sending
-multiple commands.
+object name as its value.  Multiple object names MUST be sent by sending
+multiple commands. Object names MUST be given using the object format
+negotiated through the `object-format` capability (default SHA-1).
 
 The `have` list is created by popping the first 32 commits
 from `c_pending`.  Less can be supplied if `c_pending` empties.
diff --git a/Documentation/technical/index-format.txt b/Documentation/technical/index-format.txt
index faa25c5..f9a3644 100644
--- a/Documentation/technical/index-format.txt
+++ b/Documentation/technical/index-format.txt
@@ -3,8 +3,11 @@
 
 == The Git index file has the following format
 
-  All binary numbers are in network byte order. Version 2 is described
-  here unless stated otherwise.
+  All binary numbers are in network byte order.
+  In a repository using the traditional SHA-1, checksums and object IDs
+  (object names) mentioned below are all computed using SHA-1.  Similarly,
+  in SHA-256 repositories, these values are computed using SHA-256.
+  Version 2 is described here unless stated otherwise.
 
    - A 12-byte header consisting of
 
@@ -32,8 +35,7 @@
 
      Extension data
 
-   - 160-bit SHA-1 over the content of the index file before this
-     checksum.
+   - Hash checksum over the content of the index file before this checksum.
 
 == Index entry
 
@@ -80,7 +82,7 @@
   32-bit file size
     This is the on-disk size from stat(2), truncated to 32-bit.
 
-  160-bit SHA-1 for the represented object
+  Object name for the represented object
 
   A 16-bit 'flags' field split into (high to low bits)
 
@@ -160,8 +162,8 @@
 
   - A newline (ASCII 10); and
 
-  - 160-bit object name for the object that would result from writing
-    this span of index as a tree.
+  - Object name for the object that would result from writing this span
+    of index as a tree.
 
   An entry can be in an invalidated state and is represented by having
   a negative number in the entry_count field. In this case, there is no
@@ -198,7 +200,7 @@
     stage 1 to 3 (a missing stage is represented by "0" in this field);
     and
 
-  - At most three 160-bit object names of the entry in stages from 1 to 3
+  - At most three object names of the entry in stages from 1 to 3
     (nothing is written for a missing stage).
 
 === Split index
@@ -211,8 +213,8 @@
 
   The extension consists of:
 
-  - 160-bit SHA-1 of the shared index file. The shared index file path
-    is $GIT_DIR/sharedindex.<SHA-1>. If all 160 bits are zero, the
+  - Hash of the shared index file. The shared index file path
+    is $GIT_DIR/sharedindex.<hash>. If all bits are zero, the
     index does not require a shared index file.
 
   - An ewah-encoded delete bitmap, each bit represents an entry in the
@@ -253,10 +255,10 @@
 
   - 32-bit dir_flags (see struct dir_struct)
 
-  - 160-bit SHA-1 of $GIT_DIR/info/exclude. Null SHA-1 means the file
+  - Hash of $GIT_DIR/info/exclude. A null hash means the file
     does not exist.
 
-  - 160-bit SHA-1 of core.excludesfile. Null SHA-1 means the file does
+  - Hash of core.excludesfile. A null hash means the file does
     not exist.
 
   - NUL-terminated string of per-dir exclude file name. This usually
@@ -285,13 +287,13 @@
   - An ewah bitmap, the n-th bit records "check-only" bit of
     read_directory_recursive() for the n-th directory.
 
-  - An ewah bitmap, the n-th bit indicates whether SHA-1 and stat data
+  - An ewah bitmap, the n-th bit indicates whether hash and stat data
     is valid for the n-th directory and exists in the next data.
 
   - An array of stat data. The n-th data corresponds with the n-th
     "one" bit in the previous ewah bitmap.
 
-  - An array of SHA-1. The n-th SHA-1 corresponds with the n-th "one" bit
+  - An array of hashes. The n-th hash corresponds with the n-th "one" bit
     in the previous ewah bitmap.
 
   - One NUL.
@@ -330,12 +332,12 @@
 
   - 32-bit offset to the end of the index entries
 
-  - 160-bit SHA-1 over the extension types and their sizes (but not
+  - Hash over the extension types and their sizes (but not
 	their contents).  E.g. if we have "TREE" extension that is N-bytes
 	long, "REUC" extension that is M-bytes long, followed by "EOIE",
 	then the hash would be:
 
-	SHA-1("TREE" + <binary representation of N> +
+	Hash("TREE" + <binary representation of N> +
 		"REUC" + <binary representation of M>)
 
 == Index Entry Offset Table
diff --git a/Documentation/technical/pack-format.txt b/Documentation/technical/pack-format.txt
index d3a142c..f96b2e6 100644
--- a/Documentation/technical/pack-format.txt
+++ b/Documentation/technical/pack-format.txt
@@ -1,6 +1,12 @@
 Git pack format
 ===============
 
+== Checksums and object IDs
+
+In a repository using the traditional SHA-1, pack checksums, index checksums,
+and object IDs (object names) mentioned below are all computed using SHA-1.
+Similarly, in SHA-256 repositories, these values are computed using SHA-256.
+
 == pack-*.pack files have the following format:
 
    - A header appears at the beginning and consists of the following:
@@ -26,7 +32,7 @@
 
      (deltified representation)
      n-byte type and length (3-bit type, (n-1)*7+4-bit length)
-     20-byte base object name if OBJ_REF_DELTA or a negative relative
+     base object name if OBJ_REF_DELTA or a negative relative
 	 offset from the delta object's position in the pack if this
 	 is an OBJ_OFS_DELTA object
      compressed delta data
@@ -34,7 +40,7 @@
      Observation: length of each object is encoded in a variable
      length format and is not constrained to 32-bit or anything.
 
-  - The trailer records 20-byte SHA-1 checksum of all of the above.
+  - The trailer records a pack checksum of all of the above.
 
 === Object types
 
@@ -58,8 +64,8 @@
 
 Both ofs-delta and ref-delta store the "delta" to be applied to
 another object (called 'base object') to reconstruct the object. The
-difference between them is, ref-delta directly encodes 20-byte base
-object name. If the base object is in the same pack, ofs-delta encodes
+difference between them is, ref-delta directly encodes base object
+name. If the base object is in the same pack, ofs-delta encodes
 the offset of the base object in the pack instead.
 
 The base object could also be deltified if it's in the same pack.
@@ -143,14 +149,14 @@
     object is stored in the packfile as the offset from the
     beginning.
 
-    20-byte object name.
+    one object name of the appropriate size.
 
   - The file is concluded with a trailer:
 
-    A copy of the 20-byte SHA-1 checksum at the end of
-    corresponding packfile.
+    A copy of the pack checksum at the end of the corresponding
+    packfile.
 
-    20-byte SHA-1-checksum of all of the above.
+    Index checksum of all of the above.
 
 Pack Idx file:
 
@@ -198,7 +204,7 @@
         If it is not DELTA, then deflated bytes (the size above
 		is the size before compression).
 	If it is REF_DELTA, then
-	  20-byte base object name SHA-1 (the size above is the
+	  base object name (the size above is the
 		size of the delta data that follows).
           delta data, deflated.
 	If it is OFS_DELTA, then
@@ -227,9 +233,9 @@
 
   - A 256-entry fan-out table just like v1.
 
-  - A table of sorted 20-byte SHA-1 object names.  These are
-    packed together without offset values to reduce the cache
-    footprint of the binary search for a specific object name.
+  - A table of sorted object names.  These are packed together
+    without offset values to reduce the cache footprint of the
+    binary search for a specific object name.
 
   - A table of 4-byte CRC32 values of the packed object data.
     This is new in v2 so compressed data can be copied directly
@@ -248,10 +254,10 @@
 
   - The same trailer as a v1 pack file:
 
-    A copy of the 20-byte SHA-1 checksum at the end of
+    A copy of the pack checksum at the end of
     corresponding packfile.
 
-    20-byte SHA-1-checksum of all of the above.
+    Index checksum of all of the above.
 
 == multi-pack-index (MIDX) files have the following format:
 
@@ -273,7 +279,12 @@
 	    Git only writes or recognizes version 1.
 
 	1-byte Object Id Version
-	    Git only writes or recognizes version 1 (SHA1).
+	    We infer the length of object IDs (OIDs) from this value:
+		1 => SHA-1
+		2 => SHA-256
+	    If the hash type does not match the repository's hash algorithm,
+	    the multi-pack-index file should be ignored with a warning
+	    presented to the user.
 
 	1-byte number of "chunks"
 
@@ -329,4 +340,4 @@
 
 TRAILER:
 
-	20-byte SHA1-checksum of the above contents.
+	Index checksum of the above contents.
diff --git a/Documentation/technical/protocol-capabilities.txt b/Documentation/technical/protocol-capabilities.txt
index 36ccd14..124d716 100644
--- a/Documentation/technical/protocol-capabilities.txt
+++ b/Documentation/technical/protocol-capabilities.txt
@@ -324,15 +324,19 @@
 ----------------------
 
 If the upload-pack server advertises this capability, fetch-pack may
-send "want" lines with SHA-1s that exist at the server but are not
-advertised by upload-pack.
+send "want" lines with object names that exist at the server but are not
+advertised by upload-pack. For historical reasons, the name of this
+capability contains "sha1". Object names are always given using the
+object format negotiated through the 'object-format' capability.
 
 allow-reachable-sha1-in-want
 ----------------------------
 
 If the upload-pack server advertises this capability, fetch-pack may
-send "want" lines with SHA-1s that exist at the server but are not
-advertised by upload-pack.
+send "want" lines with object names that exist at the server but are not
+advertised by upload-pack. For historical reasons, the name of this
+capability contains "sha1". Object names are always given using the
+object format negotiated through the 'object-format' capability.
 
 push-cert=<nonce>
 -----------------
diff --git a/Documentation/technical/shallow.txt b/Documentation/technical/shallow.txt
index 01dedfe..f3738ba 100644
--- a/Documentation/technical/shallow.txt
+++ b/Documentation/technical/shallow.txt
@@ -13,7 +13,7 @@
 stops after showing them; "git fsck" does not complain saying
 the commits listed on their "parent" lines do not exist).
 
-Each line contains exactly one SHA-1. When read, a commit_graft
+Each line contains exactly one object name. When read, a commit_graft
 will be constructed, which has nr_parent < 0 to make it easier
 to discern from user provided grafts.
 
diff --git a/apply.c b/apply.c
index 402d806..76dba93 100644
--- a/apply.c
+++ b/apply.c
@@ -30,8 +30,8 @@
 
 static void git_apply_config(void)
 {
-	git_config_get_string_const("apply.whitespace", &apply_default_whitespace);
-	git_config_get_string_const("apply.ignorewhitespace", &apply_default_ignorewhitespace);
+	git_config_get_string("apply.whitespace", &apply_default_whitespace);
+	git_config_get_string("apply.ignorewhitespace", &apply_default_ignorewhitespace);
 	git_config(git_xmerge_config, NULL);
 }
 
@@ -3740,6 +3740,7 @@
 
 #define EXISTS_IN_INDEX 1
 #define EXISTS_IN_WORKTREE 2
+#define EXISTS_IN_INDEX_AS_ITA 3
 
 static int check_to_create(struct apply_state *state,
 			   const char *new_name,
@@ -3747,10 +3748,23 @@
 {
 	struct stat nst;
 
-	if (state->check_index &&
-	    index_name_pos(state->repo->index, new_name, strlen(new_name)) >= 0 &&
-	    !ok_if_exists)
-		return EXISTS_IN_INDEX;
+	if (state->check_index && (!ok_if_exists || !state->cached)) {
+		int pos;
+
+		pos = index_name_pos(state->repo->index, new_name, strlen(new_name));
+		if (pos >= 0) {
+			struct cache_entry *ce = state->repo->index->cache[pos];
+
+			/* allow ITA, as they do not yet exist in the index */
+			if (!ok_if_exists && !(ce->ce_flags & CE_INTENT_TO_ADD))
+				return EXISTS_IN_INDEX;
+
+			/* ITA entries can never match working tree files */
+			if (!state->cached && (ce->ce_flags & CE_INTENT_TO_ADD))
+				return EXISTS_IN_INDEX_AS_ITA;
+		}
+	}
+
 	if (state->cached)
 		return 0;
 
@@ -3935,6 +3949,9 @@
 		case EXISTS_IN_INDEX:
 			return error(_("%s: already exists in index"), new_name);
 			break;
+		case EXISTS_IN_INDEX_AS_ITA:
+			return error(_("%s: does not match index"), new_name);
+			break;
 		case EXISTS_IN_WORKTREE:
 			return error(_("%s: already exists in working directory"),
 				     new_name);
diff --git a/bisect.c b/bisect.c
index a088a0f..d42a3a3 100644
--- a/bisect.c
+++ b/bisect.c
@@ -15,6 +15,7 @@
 #include "commit-slab.h"
 #include "commit-reach.h"
 #include "object-store.h"
+#include "dir.h"
 
 static struct oid_array good_revs;
 static struct oid_array skipped_revs;
@@ -88,15 +89,16 @@
 	**commit_weight_at(&commit_weight, elem->item) = weight;
 }
 
-static int count_interesting_parents(struct commit *commit)
+static int count_interesting_parents(struct commit *commit, unsigned bisect_flags)
 {
 	struct commit_list *p;
 	int count;
 
 	for (count = 0, p = commit->parents; p; p = p->next) {
-		if (p->item->object.flags & UNINTERESTING)
-			continue;
-		count++;
+		if (!(p->item->object.flags & UNINTERESTING))
+			count++;
+		if (bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY)
+			break;
 	}
 	return count;
 }
@@ -135,7 +137,7 @@
 	for (p = list; p; p = p->next) {
 		struct commit_list *pp;
 		struct commit *commit = p->item;
-		unsigned flags = commit->object.flags;
+		unsigned commit_flags = commit->object.flags;
 		enum object_type type;
 		unsigned long size;
 		char *buf = read_object_file(&commit->object.oid, &type,
@@ -144,9 +146,9 @@
 		int subject_len;
 
 		fprintf(stderr, "%c%c%c ",
-			(flags & TREESAME) ? ' ' : 'T',
-			(flags & UNINTERESTING) ? 'U' : ' ',
-			(flags & COUNTED) ? 'C' : ' ');
+			(commit_flags & TREESAME) ? ' ' : 'T',
+			(commit_flags & UNINTERESTING) ? 'U' : ' ',
+			(commit_flags & COUNTED) ? 'C' : ' ');
 		if (*commit_weight_at(&commit_weight, p->item))
 			fprintf(stderr, "%3d", weight(p));
 		else
@@ -171,9 +173,9 @@
 	best = list;
 	for (p = list; p; p = p->next) {
 		int distance;
-		unsigned flags = p->item->object.flags;
+		unsigned commit_flags = p->item->object.flags;
 
-		if (flags & TREESAME)
+		if (commit_flags & TREESAME)
 			continue;
 		distance = weight(p);
 		if (nr - distance < distance)
@@ -212,9 +214,9 @@
 
 	for (p = list, cnt = 0; p; p = p->next) {
 		int distance;
-		unsigned flags = p->item->object.flags;
+		unsigned commit_flags = p->item->object.flags;
 
-		if (flags & TREESAME)
+		if (commit_flags & TREESAME)
 			continue;
 		distance = weight(p);
 		if (nr - distance < distance)
@@ -259,7 +261,7 @@
  */
 static struct commit_list *do_find_bisection(struct commit_list *list,
 					     int nr, int *weights,
-					     int find_all)
+					     unsigned bisect_flags)
 {
 	int n, counted;
 	struct commit_list *p;
@@ -268,12 +270,12 @@
 
 	for (n = 0, p = list; p; p = p->next) {
 		struct commit *commit = p->item;
-		unsigned flags = commit->object.flags;
+		unsigned commit_flags = commit->object.flags;
 
 		*commit_weight_at(&commit_weight, p->item) = &weights[n++];
-		switch (count_interesting_parents(commit)) {
+		switch (count_interesting_parents(commit, bisect_flags)) {
 		case 0:
-			if (!(flags & TREESAME)) {
+			if (!(commit_flags & TREESAME)) {
 				weight_set(p, 1);
 				counted++;
 				show_list("bisection 2 count one",
@@ -314,11 +316,13 @@
 			continue;
 		if (weight(p) != -2)
 			continue;
+		if (bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY)
+			BUG("shouldn't be calling count-distance in fp mode");
 		weight_set(p, count_distance(p));
 		clear_distance(list);
 
 		/* Does it happen to be at exactly half-way? */
-		if (!find_all && halfway(p, nr))
+		if (!(bisect_flags & FIND_BISECTION_ALL) && halfway(p, nr))
 			return p;
 		counted++;
 	}
@@ -328,11 +332,14 @@
 	while (counted < nr) {
 		for (p = list; p; p = p->next) {
 			struct commit_list *q;
-			unsigned flags = p->item->object.flags;
+			unsigned commit_flags = p->item->object.flags;
 
 			if (0 <= weight(p))
 				continue;
-			for (q = p->item->parents; q; q = q->next) {
+
+			for (q = p->item->parents;
+			     q;
+			     q = bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY ? NULL : q->next) {
 				if (q->item->object.flags & UNINTERESTING)
 					continue;
 				if (0 <= weight(q))
@@ -346,7 +353,7 @@
 			 * add one for p itself if p is to be counted,
 			 * otherwise inherit it from q directly.
 			 */
-			if (!(flags & TREESAME)) {
+			if (!(commit_flags & TREESAME)) {
 				weight_set(p, weight(q)+1);
 				counted++;
 				show_list("bisection 2 count one",
@@ -356,21 +363,21 @@
 				weight_set(p, weight(q));
 
 			/* Does it happen to be at exactly half-way? */
-			if (!find_all && halfway(p, nr))
+			if (!(bisect_flags & FIND_BISECTION_ALL) && halfway(p, nr))
 				return p;
 		}
 	}
 
 	show_list("bisection 2 counted all", counted, nr, list);
 
-	if (!find_all)
+	if (!(bisect_flags & FIND_BISECTION_ALL))
 		return best_bisection(list, nr);
 	else
 		return best_bisection_sorted(list, nr);
 }
 
 void find_bisection(struct commit_list **commit_list, int *reaches,
-		    int *all, int find_all)
+		    int *all, unsigned bisect_flags)
 {
 	int nr, on_list;
 	struct commit_list *list, *p, *best, *next, *last;
@@ -386,16 +393,16 @@
 	for (nr = on_list = 0, last = NULL, p = *commit_list;
 	     p;
 	     p = next) {
-		unsigned flags = p->item->object.flags;
+		unsigned commit_flags = p->item->object.flags;
 
 		next = p->next;
-		if (flags & UNINTERESTING) {
+		if (commit_flags & UNINTERESTING) {
 			free(p);
 			continue;
 		}
 		p->next = last;
 		last = p;
-		if (!(flags & TREESAME))
+		if (!(commit_flags & TREESAME))
 			nr++;
 		on_list++;
 	}
@@ -406,9 +413,9 @@
 	weights = xcalloc(on_list, sizeof(*weights));
 
 	/* Do the real work of finding bisection commit. */
-	best = do_find_bisection(list, nr, weights, find_all);
+	best = do_find_bisection(list, nr, weights, bisect_flags);
 	if (best) {
-		if (!find_all) {
+		if (!(bisect_flags & FIND_BISECTION_ALL)) {
 			list->item = best->item;
 			free_commit_list(list->next);
 			best = list;
@@ -454,6 +461,7 @@
 static GIT_PATH_FUNC(git_path_bisect_start, "BISECT_START")
 static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
 static GIT_PATH_FUNC(git_path_bisect_terms, "BISECT_TERMS")
+static GIT_PATH_FUNC(git_path_bisect_first_parent, "BISECT_FIRST_PARENT")
 static GIT_PATH_FUNC(git_path_head_name, "head-name")
 
 static void read_bisect_paths(struct strvec *array)
@@ -983,7 +991,7 @@
  * If no_checkout is non-zero, the bisection process does not
  * checkout the trial commit but instead simply updates BISECT_HEAD.
  */
-enum bisect_error bisect_next_all(struct repository *r, const char *prefix, int no_checkout)
+enum bisect_error bisect_next_all(struct repository *r, const char *prefix)
 {
 	struct rev_info revs;
 	struct commit_list *tried;
@@ -991,21 +999,31 @@
 	enum bisect_error res = BISECT_OK;
 	struct object_id *bisect_rev;
 	char *steps_msg;
+	int no_checkout = ref_exists("BISECT_HEAD");
+	unsigned bisect_flags = 0;
 
 	read_bisect_terms(&term_bad, &term_good);
 	if (read_bisect_refs())
 		die(_("reading bisect refs failed"));
 
+	if (file_exists(git_path_bisect_first_parent()))
+		bisect_flags |= FIND_BISECTION_FIRST_PARENT_ONLY;
+
+	if (skipped_revs.nr)
+		bisect_flags |= FIND_BISECTION_ALL;
+
 	res = check_good_are_ancestors_of_bad(r, prefix, no_checkout);
 	if (res)
 		return res;
 
 	bisect_rev_setup(r, &revs, prefix, "%s", "^%s", 1);
+
+	revs.first_parent_only = !!(bisect_flags & FIND_BISECTION_FIRST_PARENT_ONLY);
 	revs.limited = 1;
 
 	bisect_common(&revs);
 
-	find_bisection(&revs.commits, &reaches, &all, !!skipped_revs.nr);
+	find_bisection(&revs.commits, &reaches, &all, bisect_flags);
 	revs.commits = managed_skipped(revs.commits, &tried);
 
 	if (!revs.commits) {
@@ -1133,6 +1151,7 @@
 	unlink_or_warn(git_path_bisect_names());
 	unlink_or_warn(git_path_bisect_run());
 	unlink_or_warn(git_path_bisect_terms());
+	unlink_or_warn(git_path_bisect_first_parent());
 	/* Cleanup head-name if it got left by an old version of git-bisect */
 	unlink_or_warn(git_path_head_name());
 	/*
diff --git a/bisect.h b/bisect.h
index 8bad8d8..ec24ac2 100644
--- a/bisect.h
+++ b/bisect.h
@@ -12,7 +12,7 @@
  * best commit, as chosen by `find_all`.
  */
 void find_bisection(struct commit_list **list, int *reaches, int *all,
-		    int find_all);
+		    unsigned bisect_flags);
 
 struct commit_list *filter_skipped(struct commit_list *list,
 				   struct commit_list **tried,
@@ -23,6 +23,9 @@
 #define BISECT_SHOW_ALL		(1<<0)
 #define REV_LIST_QUIET		(1<<1)
 
+#define FIND_BISECTION_ALL			(1u<<0)
+#define FIND_BISECTION_FIRST_PARENT_ONLY	(1u<<1)
+
 struct rev_list_info {
 	struct rev_info *revs;
 	int flags;
@@ -58,9 +61,7 @@
 	BISECT_INTERNAL_SUCCESS_MERGE_BASE = -11
 };
 
-enum bisect_error bisect_next_all(struct repository *r,
-		    const char *prefix,
-		    int no_checkout);
+enum bisect_error bisect_next_all(struct repository *r, const char *prefix);
 
 int estimate_bisect_steps(int all);
 
diff --git a/blame.c b/blame.c
index 82fa16d..1be1cd8 100644
--- a/blame.c
+++ b/blame.c
@@ -1184,6 +1184,7 @@
 	for (ent = sb->ent; ent && (next = ent->next); ent = next) {
 		if (ent->suspect == next->suspect &&
 		    ent->s_lno + ent->num_lines == next->s_lno &&
+		    ent->lno + ent->num_lines == next->lno &&
 		    ent->ignored == next->ignored &&
 		    ent->unblamable == next->unblamable) {
 			ent->num_lines += next->num_lines;
diff --git a/bugreport.c b/bugreport.c
index 09579e2..7ca0fba 100644
--- a/bugreport.c
+++ b/bugreport.c
@@ -175,10 +175,8 @@
 	/* fopen doesn't offer us an O_EXCL alternative, except with glibc. */
 	report = open(report_path.buf, O_CREAT | O_EXCL | O_WRONLY, 0666);
 
-	if (report < 0) {
-		UNLEAK(report_path);
+	if (report < 0)
 		die(_("couldn't create a new file at '%s'"), report_path.buf);
-	}
 
 	if (write_in_full(report, buffer.buf, buffer.len) < 0)
 		die_errno(_("unable to write to %s"), report_path.buf);
diff --git a/builtin/add.c b/builtin/add.c
index ab39a60..b36a99e 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -534,11 +534,11 @@
 	die_in_unpopulated_submodule(&the_index, prefix);
 	die_path_inside_submodule(&the_index, &pathspec);
 
+	dir_init(&dir);
 	if (add_new_files) {
 		int baselen;
 
 		/* Set up the default git porcelain excludes */
-		memset(&dir, 0, sizeof(dir));
 		if (!ignored_too) {
 			dir.flags |= DIR_COLLECT_IGNORED;
 			setup_standard_excludes(&dir);
@@ -611,7 +611,7 @@
 			       COMMIT_LOCK | SKIP_IF_UNCHANGED))
 		die(_("Unable to write new index file"));
 
+	dir_clear(&dir);
 	UNLEAK(pathspec);
-	UNLEAK(dir);
 	return exit_status;
 }
diff --git a/builtin/am.c b/builtin/am.c
index dd4e6c2..b5c63dd 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -98,6 +98,8 @@
 	char *author_name;
 	char *author_email;
 	char *author_date;
+	char *committer_name;
+	char *committer_email;
 	char *msg;
 	size_t msg_len;
 
@@ -130,6 +132,8 @@
  */
 static void am_state_init(struct am_state *state)
 {
+	const char *committer;
+	struct ident_split id;
 	int gpgsign;
 
 	memset(state, 0, sizeof(*state));
@@ -150,6 +154,14 @@
 
 	if (!git_config_get_bool("commit.gpgsign", &gpgsign))
 		state->sign_commit = gpgsign ? "" : NULL;
+
+	committer = git_committer_info(IDENT_STRICT);
+	if (split_ident_line(&id, committer, strlen(committer)) < 0)
+		die(_("invalid committer: %s"), committer);
+	state->committer_name =
+		xmemdupz(id.name_begin, id.name_end - id.name_begin);
+	state->committer_email =
+		xmemdupz(id.mail_begin, id.mail_end - id.mail_end);
 }
 
 /**
@@ -161,6 +173,8 @@
 	free(state->author_name);
 	free(state->author_email);
 	free(state->author_date);
+	free(state->committer_name);
+	free(state->committer_email);
 	free(state->msg);
 	strvec_clear(&state->git_apply_opts);
 }
@@ -1556,7 +1570,7 @@
 	struct object_id tree, parent, commit;
 	const struct object_id *old_oid;
 	struct commit_list *parents = NULL;
-	const char *reflog_msg, *author;
+	const char *reflog_msg, *author, *committer = NULL;
 	struct strbuf sb = STRBUF_INIT;
 
 	if (run_hook_le(NULL, "pre-applypatch", NULL))
@@ -1580,11 +1594,15 @@
 			IDENT_STRICT);
 
 	if (state->committer_date_is_author_date)
-		setenv("GIT_COMMITTER_DATE",
-			state->ignore_date ? "" : state->author_date, 1);
+		committer = fmt_ident(state->committer_name,
+				      state->author_email, WANT_COMMITTER_IDENT,
+				      state->ignore_date ? NULL
+							 : state->author_date,
+				      IDENT_STRICT);
 
-	if (commit_tree(state->msg, state->msg_len, &tree, parents, &commit,
-			author, state->sign_commit))
+	if (commit_tree_extended(state->msg, state->msg_len, &tree, parents,
+				 &commit, author, committer, state->sign_commit,
+				 NULL))
 		die(_("failed to write commit object"));
 
 	reflog_msg = getenv("GIT_REFLOG_ACTION");
diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index d193006..cdda279 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -16,9 +16,10 @@
 static GIT_PATH_FUNC(git_path_bisect_log, "BISECT_LOG")
 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 const char * const git_bisect_helper_usage[] = {
-	N_("git bisect--helper --next-all [--no-checkout]"),
+	N_("git bisect--helper --next-all"),
 	N_("git bisect--helper --write-terms <bad_term> <good_term>"),
 	N_("git bisect--helper --bisect-clean-state"),
 	N_("git bisect--helper --bisect-reset [<commit>]"),
@@ -27,7 +28,7 @@
 	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-{old,good}=<term> --term-{new,bad}=<term>]"
-					     "[--no-checkout] [<bad> [<good>...]] [--] [<paths>...]"),
+					    " [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]"),
 	NULL
 };
 
@@ -420,9 +421,10 @@
 	return res;
 }
 
-static int bisect_start(struct bisect_terms *terms, int no_checkout,
-			const char **argv, int argc)
+static int bisect_start(struct bisect_terms *terms, const char **argv, int argc)
 {
+	int no_checkout = 0;
+	int first_parent_only = 0;
 	int i, has_double_dash = 0, must_write_terms = 0, bad_seen = 0;
 	int flags, pathspec_pos, res = 0;
 	struct string_list revs = STRING_LIST_INIT_DUP;
@@ -452,6 +454,8 @@
 			break;
 		} else if (!strcmp(arg, "--no-checkout")) {
 			no_checkout = 1;
+		} else if (!strcmp(arg, "--first-parent")) {
+			first_parent_only = 1;
 		} else if (!strcmp(arg, "--term-good") ||
 			 !strcmp(arg, "--term-old")) {
 			i++;
@@ -576,6 +580,9 @@
 	 */
 	write_file(git_path_bisect_start(), "%s\n", start_head.buf);
 
+	if (first_parent_only)
+		write_file(git_path_bisect_first_parent(), "\n");
+
 	if (no_checkout) {
 		if (get_oid(start_head.buf, &oid) < 0) {
 			res = error(_("invalid ref: '%s'"), start_head.buf);
@@ -631,7 +638,7 @@
 		BISECT_TERMS,
 		BISECT_START
 	} cmdmode = 0;
-	int no_checkout = 0, res = 0, nolog = 0;
+	int res = 0, nolog = 0;
 	struct option options[] = {
 		OPT_CMDMODE(0, "next-all", &cmdmode,
 			 N_("perform 'git bisect next'"), NEXT_ALL),
@@ -653,8 +660,6 @@
 			 N_("print out the bisect terms"), BISECT_TERMS),
 		OPT_CMDMODE(0, "bisect-start", &cmdmode,
 			 N_("start the bisect session"), BISECT_START),
-		OPT_BOOL(0, "no-checkout", &no_checkout,
-			 N_("update BISECT_HEAD instead of checking out the current commit")),
 		OPT_BOOL(0, "no-log", &nolog,
 			 N_("no log for BISECT_WRITE")),
 		OPT_END()
@@ -670,7 +675,7 @@
 
 	switch (cmdmode) {
 	case NEXT_ALL:
-		res = bisect_next_all(the_repository, prefix, no_checkout);
+		res = bisect_next_all(the_repository, prefix);
 		break;
 	case WRITE_TERMS:
 		if (argc != 2)
@@ -712,7 +717,7 @@
 		break;
 	case BISECT_START:
 		set_terms(&terms, "bad", "good");
-		res = bisect_start(&terms, no_checkout, argv, argc);
+		res = bisect_start(&terms, argv, argc);
 		break;
 	default:
 		return error("BUG: unknown subcommand '%d'", cmdmode);
diff --git a/builtin/blame.c b/builtin/blame.c
index 94ef57c..eb513fb 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -842,7 +842,7 @@
 	const char *contents_from = NULL;
 	const struct option options[] = {
 		OPT_BOOL(0, "incremental", &incremental, N_("Show blame entries as we find them, incrementally")),
-		OPT_BOOL('b', NULL, &blank_boundary, N_("Show blank SHA-1 for boundary commits (Default: off)")),
+		OPT_BOOL('b', NULL, &blank_boundary, N_("Do not show object names of boundary commits (Default: off)")),
 		OPT_BOOL(0, "root", &show_root, N_("Do not treat root commits as boundaries (Default: off)")),
 		OPT_BOOL(0, "show-stats", &show_stats, N_("Show work cost statistics")),
 		OPT_BOOL(0, "progress", &show_progress, N_("Force progress reporting")),
diff --git a/builtin/check-ignore.c b/builtin/check-ignore.c
index ea5d0ae..3c65274 100644
--- a/builtin/check-ignore.c
+++ b/builtin/check-ignore.c
@@ -180,7 +180,7 @@
 	if (!no_index && read_cache() < 0)
 		die(_("index file corrupt"));
 
-	memset(&dir, 0, sizeof(dir));
+	dir_init(&dir);
 	setup_standard_excludes(&dir);
 
 	if (stdin_paths) {
@@ -190,7 +190,7 @@
 		maybe_flush_or_die(stdout, "ignore to stdout");
 	}
 
-	clear_directory(&dir);
+	dir_clear(&dir);
 
 	return !num_ignored;
 }
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 2837195..6ec8209 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1120,8 +1120,10 @@
 	if (!check_refname_format(new_branch_info->path, 0) &&
 	    !read_ref(new_branch_info->path, &branch_rev))
 		oidcpy(rev, &branch_rev);
-	else
+	else {
+		free((char *)new_branch_info->path);
 		new_branch_info->path = NULL; /* not an existing branch */
+	}
 
 	new_branch_info->commit = lookup_commit_reference_gently(the_repository, rev, 1);
 	if (!new_branch_info->commit) {
@@ -1707,6 +1709,8 @@
 		die(_("--pathspec-file-nul requires --pathspec-from-file"));
 	}
 
+	opts->pathspec.recursive = 1;
+
 	if (opts->pathspec.nr) {
 		if (1 < !!opts->writeout_stage + !!opts->force + !!opts->merge)
 			die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
diff --git a/builtin/clean.c b/builtin/clean.c
index 5a9c29a..e53ea52 100644
--- a/builtin/clean.c
+++ b/builtin/clean.c
@@ -667,7 +667,7 @@
 		if (!confirm.len)
 			break;
 
-		memset(&dir, 0, sizeof(dir));
+		dir_init(&dir);
 		pl = add_pattern_list(&dir, EXC_CMDL, "manual exclude");
 		ignore_list = strbuf_split_max(&confirm, ' ', 0);
 
@@ -698,7 +698,7 @@
 		}
 
 		strbuf_list_free(ignore_list);
-		clear_directory(&dir);
+		dir_clear(&dir);
 	}
 
 	strbuf_release(&confirm);
@@ -923,7 +923,7 @@
 	argc = parse_options(argc, argv, prefix, options, builtin_clean_usage,
 			     0);
 
-	memset(&dir, 0, sizeof(dir));
+	dir_init(&dir);
 	if (!interactive && !dry_run && !force) {
 		if (config_set)
 			die(_("clean.requireForce set to true and neither -i, -n, nor -f given; "
@@ -1021,11 +1021,7 @@
 		string_list_append(&del_list, rel);
 	}
 
-	for (i = 0; i < dir.nr; i++)
-		free(dir.entries[i]);
-
-	for (i = 0; i < dir.ignored_nr; i++)
-		free(dir.ignored[i]);
+	dir_clear(&dir);
 
 	if (interactive && del_list.nr > 0)
 		interactive_main_loop();
diff --git a/builtin/commit.c b/builtin/commit.c
index 69ac78d..5d91b13 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -847,21 +847,19 @@
 			if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS &&
 				!merge_contains_scissors)
 				wt_status_add_cut_line(s->fp);
-			status_printf_ln(s, GIT_COLOR_NORMAL,
-			    whence == FROM_MERGE
-				? _("\n"
-					"It looks like you may be committing a merge.\n"
-					"If this is not correct, please remove the file\n"
-					"	%s\n"
-					"and try again.\n")
-				: _("\n"
-					"It looks like you may be committing a cherry-pick.\n"
-					"If this is not correct, please remove the file\n"
-					"	%s\n"
-					"and try again.\n"),
+			status_printf_ln(
+				s, GIT_COLOR_NORMAL,
 				whence == FROM_MERGE ?
-					git_path_merge_head(the_repository) :
-					git_path_cherry_pick_head(the_repository));
+					      _("\n"
+					  "It looks like you may be committing a merge.\n"
+					  "If this is not correct, please run\n"
+					  "	git update-ref -d MERGE_HEAD\n"
+					  "and try again.\n") :
+					      _("\n"
+					  "It looks like you may be committing a cherry-pick.\n"
+					  "If this is not correct, please run\n"
+					  "	git update-ref -d CHERRY_PICK_HEAD\n"
+					  "and try again.\n"));
 		}
 
 		fprintf(s->fp, "\n");
@@ -1674,8 +1672,8 @@
 	}
 
 	if (commit_tree_extended(sb.buf, sb.len, &active_cache_tree->oid,
-				 parents, &oid, author_ident.buf, sign_commit,
-				 extra)) {
+				 parents, &oid, author_ident.buf, NULL,
+				 sign_commit, extra)) {
 		rollback_index_files();
 		die(_("failed to write commit object"));
 	}
diff --git a/builtin/fetch.c b/builtin/fetch.c
index c49f0e9..0f23dd4 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -56,6 +56,7 @@
 #define PRUNE_TAGS_BY_DEFAULT 0 /* do we prune tags by default? */
 
 static int all, append, dry_run, force, keep, multiple, update_head_ok;
+static int write_fetch_head = 1;
 static int verbosity, deepen_relative, set_upstream;
 static int progress = -1;
 static int enable_auto_gc = 1;
@@ -162,6 +163,8 @@
 		    PARSE_OPT_OPTARG, option_fetch_parse_recurse_submodules),
 	OPT_BOOL(0, "dry-run", &dry_run,
 		 N_("dry run")),
+	OPT_BOOL(0, "write-fetch-head", &write_fetch_head,
+		 N_("write fetched references to the FETCH_HEAD file")),
 	OPT_BOOL('k', "keep", &keep, N_("keep downloaded pack")),
 	OPT_BOOL('u', "update-head-ok", &update_head_ok,
 		    N_("allow updating of HEAD ref")),
@@ -645,7 +648,7 @@
 	struct ref *rm;
 	const char *format = "full";
 
-	git_config_get_string_const("fetch.output", &format);
+	git_config_get_string_tmp("fetch.output", &format);
 	if (!strcasecmp(format, "full"))
 		compact_format = 0;
 	else if (!strcasecmp(format, "compact"))
@@ -893,7 +896,9 @@
 	const char *what, *kind;
 	struct ref *rm;
 	char *url;
-	const char *filename = dry_run ? "/dev/null" : git_path_fetch_head(the_repository);
+	const char *filename = (!write_fetch_head
+				? "/dev/null"
+				: git_path_fetch_head(the_repository));
 	int want_status;
 	int summary_width = transport_summary_width(ref_map);
 
@@ -1327,7 +1332,7 @@
 	}
 
 	/* if not appending, truncate FETCH_HEAD */
-	if (!append && !dry_run) {
+	if (!append && write_fetch_head) {
 		retcode = truncate_fetch_head();
 		if (retcode)
 			goto cleanup;
@@ -1594,7 +1599,7 @@
 	int i, result = 0;
 	struct strvec argv = STRVEC_INIT;
 
-	if (!append && !dry_run) {
+	if (!append && write_fetch_head) {
 		int errcode = truncate_fetch_head();
 		if (errcode)
 			return errcode;
@@ -1795,6 +1800,10 @@
 	if (depth || deepen_since || deepen_not.nr)
 		deepen = 1;
 
+	/* FETCH_HEAD never gets updated in --dry-run mode */
+	if (dry_run)
+		write_fetch_head = 0;
+
 	if (all) {
 		if (argc == 1)
 			die(_("fetch --all does not take a repository argument"));
diff --git a/builtin/grep.c b/builtin/grep.c
index cee9db3..f58979b 100644
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -693,7 +693,7 @@
 	struct dir_struct dir;
 	int i, hit = 0;
 
-	memset(&dir, 0, sizeof(dir));
+	dir_init(&dir);
 	if (!use_index)
 		dir.flags |= DIR_NO_GITLINKS;
 	if (exc_std)
@@ -705,6 +705,7 @@
 		if (hit && opt->status_only)
 			break;
 	}
+	dir_clear(&dir);
 	return hit;
 }
 
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index f865666..9721bf1 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -1798,9 +1798,22 @@
 
 	if (HAVE_THREADS && !nr_threads) {
 		nr_threads = online_cpus();
-		/* An experiment showed that more threads does not mean faster */
-		if (nr_threads > 3)
-			nr_threads = 3;
+		/*
+		 * Experiments show that going above 20 threads doesn't help,
+		 * no matter how many cores you have. Below that, we tend to
+		 * max at half the number of online_cpus(), presumably because
+		 * half of those are hyperthreads rather than full cores. We'll
+		 * never reduce the level below "3", though, to match a
+		 * historical value that nobody complained about.
+		 */
+		if (nr_threads < 4)
+			; /* too few cores to consider capping */
+		else if (nr_threads < 6)
+			nr_threads = 3; /* historic cap */
+		else if (nr_threads < 40)
+			nr_threads /= 2;
+		else
+			nr_threads = 20; /* hard cap */
 	}
 
 	curr_pack = open_pack_file(pack_name);
diff --git a/builtin/init-db.c b/builtin/init-db.c
index f70076d..bbc9bc7 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -563,6 +563,9 @@
 
 	argc = parse_options(argc, argv, prefix, init_db_options, init_db_usage, 0);
 
+	if (real_git_dir && is_bare_repository_cfg == 1)
+		die(_("--separate-git-dir and --bare are mutually exclusive"));
+
 	if (real_git_dir && !is_absolute_path(real_git_dir))
 		real_git_dir = real_pathdup(real_git_dir, 1);
 
@@ -658,6 +661,8 @@
 				   get_git_work_tree());
 	}
 	else {
+		if (real_git_dir)
+			die(_("--separate-git-dir incompatible with bare repository"));
 		if (work_tree)
 			set_git_work_tree(work_tree);
 	}
diff --git a/builtin/log.c b/builtin/log.c
index 33528fe..b58f8da 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -599,8 +599,8 @@
 static void show_setup_revisions_tweak(struct rev_info *rev,
 				       struct setup_revision_opt *opt)
 {
-	if (rev->ignore_merges) {
-		/* There was no "-m" on the command line */
+	if (rev->ignore_merges < 0) {
+		/* There was no "-m" variant on the command line */
 		rev->ignore_merges = 0;
 		if (!rev->first_parent_only && !rev->combine_merges) {
 			/* No "--first-parent", "-c", or "--cc" */
@@ -732,8 +732,7 @@
 	if (!rev->diffopt.output_format && rev->combine_merges)
 		rev->diffopt.output_format = DIFF_FORMAT_PATCH;
 
-	/* Turn -m on when --cc/-c was given */
-	if (rev->combine_merges)
+	if (rev->first_parent_only && rev->ignore_merges < 0)
 		rev->ignore_merges = 0;
 }
 
diff --git a/builtin/ls-files.c b/builtin/ls-files.c
index 30a4c10..c8eae89 100644
--- a/builtin/ls-files.c
+++ b/builtin/ls-files.c
@@ -584,7 +584,7 @@
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage_with_options(ls_files_usage, builtin_ls_files_options);
 
-	memset(&dir, 0, sizeof(dir));
+	dir_init(&dir);
 	prefix = cmd_prefix;
 	if (prefix)
 		prefix_len = strlen(prefix);
@@ -688,6 +688,6 @@
 		return bad ? 1 : 0;
 	}
 
-	UNLEAK(dir);
+	dir_clear(&dir);
 	return 0;
 }
diff --git a/builtin/ls-remote.c b/builtin/ls-remote.c
index ea91679..092917e 100644
--- a/builtin/ls-remote.c
+++ b/builtin/ls-remote.c
@@ -83,6 +83,8 @@
 			     PARSE_OPT_STOP_AT_NON_OPTION);
 	dest = argv[0];
 
+	UNLEAK(sorting);
+
 	if (argc > 1) {
 		int i;
 		pattern = xcalloc(argc, sizeof(const char *));
@@ -107,7 +109,6 @@
 
 	if (get_url) {
 		printf("%s\n", *remote->url);
-		UNLEAK(sorting);
 		return 0;
 	}
 
@@ -122,10 +123,8 @@
 		int hash_algo = hash_algo_by_ptr(transport_get_hash_algo(transport));
 		repo_set_hash_algo(the_repository, hash_algo);
 	}
-	if (transport_disconnect(transport)) {
-		UNLEAK(sorting);
+	if (transport_disconnect(transport))
 		return 1;
-	}
 
 	if (!dest && !quiet)
 		fprintf(stderr, "From %s\n", *remote->url);
@@ -150,7 +149,6 @@
 		status = 0; /* we found something */
 	}
 
-	UNLEAK(sorting);
 	ref_array_clear(&ref_array);
 	return status;
 }
diff --git a/builtin/merge.c b/builtin/merge.c
index 74829a8..b9a89ba 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1348,7 +1348,7 @@
 		else
 			die(_("You have not concluded your merge (MERGE_HEAD exists)."));
 	}
-	if (file_exists(git_path_cherry_pick_head(the_repository))) {
+	if (ref_exists("CHERRY_PICK_HEAD")) {
 		if (advice_resolve_conflict)
 			die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
 			    "Please, commit your changes before you merge."));
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index a9dcd25..725dd04 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -521,7 +521,7 @@
 	int all = 0, transform_stdin = 0, allow_undefined = 1, always = 0, peel_tag = 0;
 	struct name_ref_data data = { 0, 0, STRING_LIST_INIT_NODUP, STRING_LIST_INIT_NODUP };
 	struct option opts[] = {
-		OPT_BOOL(0, "name-only", &data.name_only, N_("print only names (no SHA-1)")),
+		OPT_BOOL(0, "name-only", &data.name_only, N_("print only ref-based names (no object names)")),
 		OPT_BOOL(0, "tags", &data.tags_only, N_("only use tags to name the commits")),
 		OPT_STRING_LIST(0, "refs", &data.ref_filters, N_("pattern"),
 				   N_("only use refs matching <pattern>")),
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index a8692d2..5617c01 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -3357,7 +3357,7 @@
 			if (starts_with(line, "--shallow ")) {
 				struct object_id oid;
 				if (get_oid_hex(line + 10, &oid))
-					die("not an SHA-1 '%s'", line + 10);
+					die("not an object name '%s'", line + 10);
 				register_shallow(the_repository, &oid);
 				use_bitmap_index = 0;
 				continue;
diff --git a/builtin/rebase.c b/builtin/rebase.c
index dadb52f..c4ff203 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -92,6 +92,8 @@
 	int autosquash;
 	char *gpg_sign_opt;
 	int autostash;
+	int committer_date_is_author_date;
+	int ignore_date;
 	char *cmd;
 	int allow_empty_message;
 	int rebase_merges, rebase_cousins;
@@ -130,8 +132,12 @@
 	replay.quiet = !(opts->flags & REBASE_NO_QUIET);
 	replay.verbose = opts->flags & REBASE_VERBOSE;
 	replay.reschedule_failed_exec = opts->reschedule_failed_exec;
+	replay.committer_date_is_author_date =
+					opts->committer_date_is_author_date;
+	replay.ignore_date = opts->ignore_date;
 	replay.gpg_sign = xstrdup_or_null(opts->gpg_sign_opt);
 	replay.strategy = opts->strategy;
+
 	if (opts->strategy_opts)
 		parse_strategy_opts(&replay, opts->strategy_opts);
 
@@ -1289,6 +1295,7 @@
 	struct strbuf revisions = STRBUF_INIT;
 	struct strbuf buf = STRBUF_INIT;
 	struct object_id merge_base;
+	int ignore_whitespace = 0;
 	enum action action = ACTION_NONE;
 	const char *gpg_sign = NULL;
 	struct string_list exec = STRING_LIST_INIT_NODUP;
@@ -1318,16 +1325,17 @@
 			PARSE_OPT_NOARG, NULL, REBASE_DIFFSTAT },
 		OPT_BOOL(0, "signoff", &options.signoff,
 			 N_("add a Signed-off-by: line to each commit")),
-		OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &options.git_am_opts,
-				  NULL, N_("passed to 'git am'"),
-				  PARSE_OPT_NOARG),
-		OPT_PASSTHRU_ARGV(0, "committer-date-is-author-date",
-				  &options.git_am_opts, NULL,
-				  N_("passed to 'git am'"), PARSE_OPT_NOARG),
-		OPT_PASSTHRU_ARGV(0, "ignore-date", &options.git_am_opts, NULL,
-				  N_("passed to 'git am'"), PARSE_OPT_NOARG),
+		OPT_BOOL(0, "committer-date-is-author-date",
+			 &options.committer_date_is_author_date,
+			 N_("make committer date match author date")),
+		OPT_BOOL(0, "reset-author-date", &options.ignore_date,
+			 N_("ignore author date and use current date")),
+		OPT_HIDDEN_BOOL(0, "ignore-date", &options.ignore_date,
+				N_("synonym of --reset-author-date")),
 		OPT_PASSTHRU_ARGV('C', NULL, &options.git_am_opts, N_("n"),
 				  N_("passed to 'git apply'"), 0),
+		OPT_BOOL(0, "ignore-whitespace", &ignore_whitespace,
+			 N_("ignore changes in whitespace")),
 		OPT_PASSTHRU_ARGV(0, "whitespace", &options.git_am_opts,
 				  N_("action"), N_("passed to 'git apply'"), 0),
 		OPT_BIT('f', "force-rebase", &options.flags,
@@ -1624,12 +1632,12 @@
 	    options.autosquash) {
 		allow_preemptive_ff = 0;
 	}
+	if (options.committer_date_is_author_date || options.ignore_date)
+		options.flags |= REBASE_FORCE;
 
 	for (i = 0; i < options.git_am_opts.nr; i++) {
 		const char *option = options.git_am_opts.v[i], *p;
-		if (!strcmp(option, "--committer-date-is-author-date") ||
-		    !strcmp(option, "--ignore-date") ||
-		    !strcmp(option, "--whitespace=fix") ||
+		if (!strcmp(option, "--whitespace=fix") ||
 		    !strcmp(option, "--whitespace=strip"))
 			allow_preemptive_ff = 0;
 		else if (skip_prefix(option, "-C", &p)) {
@@ -1682,6 +1690,23 @@
 		imply_merge(&options, "--rebase-merges");
 	}
 
+	if (options.type == REBASE_APPLY) {
+		if (ignore_whitespace)
+			strvec_push(&options.git_am_opts,
+				    "--ignore-whitespace");
+		if (options.committer_date_is_author_date)
+			strvec_push(&options.git_am_opts,
+				    "--committer-date-is-author-date");
+		if (options.ignore_date)
+			strvec_push(&options.git_am_opts, "--ignore-date");
+	} else {
+		/* REBASE_MERGE and PRESERVE_MERGES */
+		if (ignore_whitespace) {
+			string_list_append(&strategy_options,
+					   "ignore-space-change");
+		}
+	}
+
 	if (strategy_options.nr) {
 		int i;
 
diff --git a/builtin/remote.c b/builtin/remote.c
index c8240e9..542f56e 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -478,6 +478,7 @@
 	struct ref *fetch_map = NULL, **fetch_map_tail = &fetch_map;
 	struct refspec_item refspec;
 
+	memset(&refspec, 0, sizeof(refspec));
 	refspec.force = 0;
 	refspec.pattern = 1;
 	refspec.src = refspec.dst = "refs/heads/*";
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index f520111..25c6c3b 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -637,8 +637,15 @@
 
 	if (bisect_list) {
 		int reaches, all;
+		unsigned bisect_flags = 0;
 
-		find_bisection(&revs.commits, &reaches, &all, bisect_find_all);
+		if (bisect_find_all)
+			bisect_flags |= FIND_BISECTION_ALL;
+
+		if (revs.first_parent_only)
+			bisect_flags |= FIND_BISECTION_FIRST_PARENT_ONLY;
+
+		find_bisection(&revs.commits, &reaches, &all, bisect_flags);
 
 		if (bisect_show_vars)
 			return show_bisect_vars(&info, reaches, all);
diff --git a/builtin/stash.c b/builtin/stash.c
index 10d8763..4bdfaf8 100644
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -864,7 +864,7 @@
 	int found = 0;
 	struct dir_struct dir;
 
-	memset(&dir, 0, sizeof(dir));
+	dir_init(&dir);
 	if (include_untracked != INCLUDE_ALL_FILES)
 		setup_standard_excludes(&dir);
 
@@ -875,12 +875,9 @@
 		strbuf_addstr(untracked_files, ent->name);
 		/* NUL-terminate: will be fed to update-index -z */
 		strbuf_addch(untracked_files, '\0');
-		free(ent);
 	}
 
-	free(dir.entries);
-	free(dir.ignored);
-	clear_directory(&dir);
+	dir_clear(&dir);
 	return found;
 }
 
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index df135ab..a59d8e4 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -1511,7 +1511,7 @@
 		if (parse_submodule_update_strategy(update, out) < 0)
 			die(_("Invalid update mode '%s' for submodule path '%s'"),
 				update, path);
-	} else if (!repo_config_get_string_const(r, key, &val)) {
+	} else if (!repo_config_get_string_tmp(r, key, &val)) {
 		if (parse_submodule_update_strategy(val, out) < 0)
 			die(_("Invalid update mode '%s' configured for submodule path '%s'"),
 				val, path);
@@ -1667,7 +1667,7 @@
 	}
 
 	key = xstrfmt("submodule.%s.update", sub->name);
-	if (!repo_config_get_string_const(the_repository, key, &update_string)) {
+	if (!repo_config_get_string_tmp(the_repository, key, &update_string)) {
 		update_type = parse_submodule_update_type(update_string);
 	} else {
 		update_type = sub->update_strategy.type;
@@ -1690,7 +1690,7 @@
 
 	strbuf_reset(&sb);
 	strbuf_addf(&sb, "submodule.%s.url", sub->name);
-	if (repo_config_get_string_const(the_repository, sb.buf, &url)) {
+	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);
@@ -1747,8 +1747,8 @@
 					      "--no-single-branch");
 
 cleanup:
-	strbuf_reset(&displaypath_sb);
-	strbuf_reset(&sb);
+	strbuf_release(&displaypath_sb);
+	strbuf_release(&sb);
 	if (need_free_url)
 		free((void*)url);
 
@@ -1976,7 +1976,7 @@
 		return NULL;
 
 	key = xstrfmt("submodule.%s.branch", sub->name);
-	if (repo_config_get_string_const(the_repository, key, &branch))
+	if (repo_config_get_string_tmp(the_repository, key, &branch))
 		branch = sub->branch;
 	free(key);
 
@@ -2101,7 +2101,7 @@
 {
 	const struct submodule *sub;
 	const char *path;
-	char *cw;
+	const char *cw;
 	struct repository subrepo;
 
 	if (argc != 2)
@@ -2116,7 +2116,7 @@
 	if (repo_submodule_init(&subrepo, the_repository, sub))
 		die(_("could not get a repository handle for submodule '%s'"), path);
 
-	if (!repo_config_get_string(&subrepo, "core.worktree", &cw)) {
+	if (!repo_config_get_string_tmp(&subrepo, "core.worktree", &cw)) {
 		char *cfg_file, *abs_path;
 		const char *rel_path;
 		struct strbuf sb = STRBUF_INIT;
diff --git a/cache.h b/cache.h
index 0290849..4cad61f 100644
--- a/cache.h
+++ b/cache.h
@@ -921,8 +921,8 @@
 extern int prefer_symlink_refs;
 extern int warn_ambiguous_refs;
 extern int warn_on_object_refname_ambiguity;
-extern const char *apply_default_whitespace;
-extern const char *apply_default_ignorewhitespace;
+extern char *apply_default_whitespace;
+extern char *apply_default_ignorewhitespace;
 extern const char *git_attributes_file;
 extern const char *git_hooks_path;
 extern int zlib_compression_level;
diff --git a/checkout.c b/checkout.c
index c72e9f9..6586e30 100644
--- a/checkout.c
+++ b/checkout.c
@@ -47,7 +47,7 @@
 {
 	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
 	const char *default_remote = NULL;
-	if (!git_config_get_string_const("checkout.defaultremote", &default_remote))
+	if (!git_config_get_string_tmp("checkout.defaultremote", &default_remote))
 		cb_data.default_remote = default_remote;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
@@ -55,7 +55,6 @@
 	if (dwim_remotes_matched)
 		*dwim_remotes_matched = cb_data.num_matches;
 	free(cb_data.src_ref);
-	free((char *)default_remote);
 	if (cb_data.num_matches == 1) {
 		free(cb_data.default_dst_ref);
 		free(cb_data.default_dst_oid);
diff --git a/commit-graph.c b/commit-graph.c
index e51c91d..0ed003e 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -179,7 +179,14 @@
 
 static uint8_t oid_version(void)
 {
-	return 1;
+	switch (hash_algo_by_ptr(the_hash_algo)) {
+	case GIT_HASH_SHA1:
+		return 1;
+	case GIT_HASH_SHA256:
+		return 2;
+	default:
+		die(_("invalid hash version"));
+	}
 }
 
 static struct commit_graph *alloc_commit_graph(void)
diff --git a/commit.c b/commit.c
index 4ce8cb3..bc741e7 100644
--- a/commit.c
+++ b/commit.c
@@ -1316,8 +1316,8 @@
 	int result;
 
 	append_merge_tag_headers(parents, &tail);
-	result = commit_tree_extended(msg, msg_len, tree, parents, ret,
-				      author, sign_commit, extra);
+	result = commit_tree_extended(msg, msg_len, tree, parents, ret, author,
+				      NULL, sign_commit, extra);
 	free_commit_extra_headers(extra);
 	return result;
 }
@@ -1440,7 +1440,8 @@
 int commit_tree_extended(const char *msg, size_t msg_len,
 			 const struct object_id *tree,
 			 struct commit_list *parents, struct object_id *ret,
-			 const char *author, const char *sign_commit,
+			 const char *author, const char *committer,
+			 const char *sign_commit,
 			 struct commit_extra_header *extra)
 {
 	int result;
@@ -1473,7 +1474,9 @@
 	if (!author)
 		author = git_author_info(IDENT_STRICT);
 	strbuf_addf(&buffer, "author %s\n", author);
-	strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
+	if (!committer)
+		committer = git_committer_info(IDENT_STRICT);
+	strbuf_addf(&buffer, "committer %s\n", committer);
 	if (!encoding_is_utf8)
 		strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
 
diff --git a/commit.h b/commit.h
index e901538..bd73b84 100644
--- a/commit.h
+++ b/commit.h
@@ -270,10 +270,9 @@
 
 int commit_tree_extended(const char *msg, size_t msg_len,
 			 const struct object_id *tree,
-			 struct commit_list *parents,
-			 struct object_id *ret, const char *author,
-			 const char *sign_commit,
-			 struct commit_extra_header *);
+			 struct commit_list *parents, struct object_id *ret,
+			 const char *author, const char *committer,
+			 const char *sign_commit, struct commit_extra_header *);
 
 struct commit_extra_header *read_commit_extra_headers(struct commit *, const char **);
 
diff --git a/compat/mingw.c b/compat/mingw.c
index 4454b3e..a00f331 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -290,6 +290,9 @@
 	if (xutftowcs_path(wpathname, pathname) < 0)
 		return -1;
 
+	if (DeleteFileW(wpathname))
+		return 0;
+
 	/* read-only files cannot be removed */
 	_wchmod(wpathname, 0666);
 	while ((ret = _wunlink(wpathname)) == -1 && tries < ARRAY_SIZE(delay)) {
diff --git a/config.c b/config.c
index 2b79fe7..2bdff44 100644
--- a/config.c
+++ b/config.c
@@ -2006,18 +2006,27 @@
 	return e ? &e->value_list : NULL;
 }
 
-int git_configset_get_string_const(struct config_set *cs, const char *key, const char **dest)
+int git_configset_get_string(struct config_set *cs, const char *key, char **dest)
 {
 	const char *value;
 	if (!git_configset_get_value(cs, key, &value))
-		return git_config_string(dest, key, value);
+		return git_config_string((const char **)dest, key, value);
 	else
 		return 1;
 }
 
-int git_configset_get_string(struct config_set *cs, const char *key, char **dest)
+int git_configset_get_string_tmp(struct config_set *cs, const char *key,
+				 const char **dest)
 {
-	return git_configset_get_string_const(cs, key, (const char **)dest);
+	const char *value;
+	if (!git_configset_get_value(cs, key, &value)) {
+		if (!value)
+			return config_error_nonbool(key);
+		*dest = value;
+		return 0;
+	} else {
+		return 1;
+	}
 }
 
 int git_configset_get_int(struct config_set *cs, const char *key, int *dest)
@@ -2147,22 +2156,26 @@
 	return git_configset_get_value_multi(repo->config, key);
 }
 
-int repo_config_get_string_const(struct repository *repo,
-				 const char *key, const char **dest)
+int repo_config_get_string(struct repository *repo,
+			   const char *key, char **dest)
 {
 	int ret;
 	git_config_check_init(repo);
-	ret = git_configset_get_string_const(repo->config, key, dest);
+	ret = git_configset_get_string(repo->config, key, dest);
 	if (ret < 0)
 		git_die_config(key, NULL);
 	return ret;
 }
 
-int repo_config_get_string(struct repository *repo,
-			   const char *key, char **dest)
+int repo_config_get_string_tmp(struct repository *repo,
+			       const char *key, const char **dest)
 {
+	int ret;
 	git_config_check_init(repo);
-	return repo_config_get_string_const(repo, key, (const char **)dest);
+	ret = git_configset_get_string_tmp(repo->config, key, dest);
+	if (ret < 0)
+		git_die_config(key, NULL);
+	return ret;
 }
 
 int repo_config_get_int(struct repository *repo,
@@ -2232,16 +2245,16 @@
 	return repo_config_get_value_multi(the_repository, key);
 }
 
-int git_config_get_string_const(const char *key, const char **dest)
-{
-	return repo_config_get_string_const(the_repository, key, dest);
-}
-
 int git_config_get_string(const char *key, char **dest)
 {
 	return repo_config_get_string(the_repository, key, dest);
 }
 
+int git_config_get_string_tmp(const char *key, const char **dest)
+{
+	return repo_config_get_string_tmp(the_repository, key, dest);
+}
+
 int git_config_get_int(const char *key, int *dest)
 {
 	return repo_config_get_int(the_repository, key, dest);
@@ -2274,7 +2287,7 @@
 
 int git_config_get_expiry(const char *key, const char **output)
 {
-	int ret = git_config_get_string_const(key, output);
+	int ret = git_config_get_string(key, (char **)output);
 	if (ret)
 		return ret;
 	if (strcmp(*output, "now")) {
@@ -2287,11 +2300,11 @@
 
 int git_config_get_expiry_in_days(const char *key, timestamp_t *expiry, timestamp_t now)
 {
-	char *expiry_string;
+	const char *expiry_string;
 	intmax_t days;
 	timestamp_t when;
 
-	if (git_config_get_string(key, &expiry_string))
+	if (git_config_get_string_tmp(key, &expiry_string))
 		return 1; /* no such thing */
 
 	if (git_parse_signed(expiry_string, &days, maximum_signed_value_of_type(int))) {
diff --git a/config.h b/config.h
index 0608744..91cdfbf 100644
--- a/config.h
+++ b/config.h
@@ -458,8 +458,8 @@
  */
 int git_configset_get_value(struct config_set *cs, const char *key, const char **dest);
 
-int git_configset_get_string_const(struct config_set *cs, const char *key, const char **dest);
 int git_configset_get_string(struct config_set *cs, const char *key, char **dest);
+int git_configset_get_string_tmp(struct config_set *cs, const char *key, const char **dest);
 int git_configset_get_int(struct config_set *cs, const char *key, int *dest);
 int git_configset_get_ulong(struct config_set *cs, const char *key, unsigned long *dest);
 int git_configset_get_bool(struct config_set *cs, const char *key, int *dest);
@@ -474,10 +474,10 @@
 			  const char *key, const char **value);
 const struct string_list *repo_config_get_value_multi(struct repository *repo,
 						      const char *key);
-int repo_config_get_string_const(struct repository *repo,
-				 const char *key, const char **dest);
 int repo_config_get_string(struct repository *repo,
 			   const char *key, char **dest);
+int repo_config_get_string_tmp(struct repository *repo,
+			       const char *key, const char **dest);
 int repo_config_get_int(struct repository *repo,
 			const char *key, int *dest);
 int repo_config_get_ulong(struct repository *repo,
@@ -529,13 +529,14 @@
  * error message and returns -1. When the configuration variable `key` is
  * not found, returns 1 without touching `dest`.
  */
-int git_config_get_string_const(const char *key, const char **dest);
+int git_config_get_string(const char *key, char **dest);
 
 /**
- * Similar to `git_config_get_string_const`, except that retrieved value
- * copied into the `dest` parameter is a mutable string.
+ * Similar to `git_config_get_string`, but does not allocate any new
+ * memory; on success `dest` will point to memory owned by the config
+ * machinery, which could be invalidated if it is discarded and reloaded.
  */
-int git_config_get_string(const char *key, char **dest);
+int git_config_get_string_tmp(const char *key, const char **dest);
 
 /**
  * Finds and parses the value to an integer for the configuration variable
diff --git a/connect.c b/connect.c
index 0b6aba1..8b8f56c 100644
--- a/connect.c
+++ b/connect.c
@@ -1052,7 +1052,7 @@
 	if ((ssh = getenv("GIT_SSH_COMMAND")))
 		return ssh;
 
-	if (!git_config_get_string_const("core.sshcommand", &ssh))
+	if (!git_config_get_string_tmp("core.sshcommand", &ssh))
 		return ssh;
 
 	return NULL;
@@ -1071,7 +1071,7 @@
 {
 	const char *variant = getenv("GIT_SSH_VARIANT");
 
-	if (!variant && git_config_get_string_const("ssh.variant", &variant))
+	if (!variant && git_config_get_string_tmp("ssh.variant", &variant))
 		return;
 
 	if (!strcmp(variant, "auto"))
diff --git a/connected.c b/connected.c
index 21c1ebe..b18299f 100644
--- a/connected.c
+++ b/connected.c
@@ -22,14 +22,13 @@
 		    struct check_connected_options *opt)
 {
 	struct child_process rev_list = CHILD_PROCESS_INIT;
+	FILE *rev_list_in;
 	struct check_connected_options defaults = CHECK_CONNECTED_INIT;
-	char commit[GIT_MAX_HEXSZ + 1];
 	struct object_id oid;
 	int err = 0;
 	struct packed_git *new_pack = NULL;
 	struct transport *transport;
 	size_t base_len;
-	const unsigned hexsz = the_hash_algo->hexsz;
 
 	if (!opt)
 		opt = &defaults;
@@ -122,7 +121,8 @@
 
 	sigchain_push(SIGPIPE, SIG_IGN);
 
-	commit[hexsz] = '\n';
+	rev_list_in = xfdopen(rev_list.in, "w");
+
 	do {
 		/*
 		 * If index-pack already checked that:
@@ -135,16 +135,17 @@
 		if (new_pack && find_pack_entry_one(oid.hash, new_pack))
 			continue;
 
-		memcpy(commit, oid_to_hex(&oid), hexsz);
-		if (write_in_full(rev_list.in, commit, hexsz + 1) < 0) {
-			if (errno != EPIPE && errno != EINVAL)
-				error_errno(_("failed write to rev-list"));
-			err = -1;
+		if (fprintf(rev_list_in, "%s\n", oid_to_hex(&oid)) < 0)
 			break;
-		}
 	} while (!fn(cb_data, &oid));
 
-	if (close(rev_list.in))
+	if (ferror(rev_list_in) || fflush(rev_list_in)) {
+		if (errno != EPIPE && errno != EINVAL)
+			error_errno(_("failed write to rev-list"));
+		err = -1;
+	}
+
+	if (fclose(rev_list_in))
 		err = error_errno(_("failed to close rev-list's stdin"));
 
 	sigchain_pop(SIGPIPE);
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 0fdb5da..9147fba 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -39,6 +39,11 @@
 #     When set to "1", do not include "DWIM" suggestions in git-checkout
 #     and git-switch completion (e.g., completing "foo" when "origin/foo"
 #     exists).
+#
+#   GIT_COMPLETION_SHOW_ALL
+#
+#     When set to "1" suggest all options, including options which are
+#     typically hidden (e.g. '--allow-empty' for 'git commit').
 
 case "$COMP_WORDBREAKS" in
 *:*) : great ;;
@@ -411,10 +416,17 @@
 	local options
 	eval "options=\${$var-}"
 
+	local completion_helper
+	if [ "$GIT_COMPLETION_SHOW_ALL" = "1" ]; then
+		completion_helper="--git-completion-helper-all"
+	else
+		completion_helper="--git-completion-helper"
+	fi
+
 	if [ -z "$options" ]; then
 		# leading and trailing spaces are significant to make
 		# option removal work correctly.
-		options=" $incl $(__git ${cmd/_/ } --git-completion-helper) " || return
+		options=" $incl $(__git ${cmd/_/ } $completion_helper) " || return
 
 		for i in $excl; do
 			options="${options/ $i / }"
@@ -1712,8 +1724,8 @@
 }
 
 __git_mergetools_common="diffuse diffmerge ecmerge emerge kdiff3 meld opendiff
-			tkdiff vimdiff gvimdiff xxdiff araxis p4merge bc
-			codecompare smerge
+			tkdiff vimdiff nvimdiff gvimdiff xxdiff araxis p4merge
+			bc codecompare smerge
 "
 
 _git_difftool ()
diff --git a/contrib/subtree/git-subtree.txt b/contrib/subtree/git-subtree.txt
index 352deda..0db02fe 100644
--- a/contrib/subtree/git-subtree.txt
+++ b/contrib/subtree/git-subtree.txt
@@ -139,12 +139,12 @@
 
 -m <message>::
 --message=<message>::
-	This option is only valid for add, merge and pull (unsure).
+	This option is only valid for add, merge, pull, and split --rejoin.
 	Specify <message> as the commit message for the merge commit.
 
 
-OPTIONS FOR add, merge, push, pull
-----------------------------------
+OPTIONS FOR add, merge, and pull
+--------------------------------
 --squash::
 	This option is only valid for add, merge, and pull
 	commands.
diff --git a/diff-lib.c b/diff-lib.c
index 25fd2de..50521e2 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -219,7 +219,8 @@
 				continue;
 			} else if (revs->diffopt.ita_invisible_in_index &&
 				   ce_intent_to_add(ce)) {
-				diff_addremove(&revs->diffopt, '+', ce->ce_mode,
+				newmode = ce_mode_from_stat(ce, st.st_mode);
+				diff_addremove(&revs->diffopt, '+', newmode,
 					       &null_oid, 0, ce->name, 0);
 				continue;
 			}
diff --git a/diff.c b/diff.c
index f9709de..e3a5ee3 100644
--- a/diff.c
+++ b/diff.c
@@ -4319,7 +4319,10 @@
 	}
 	if (one && two && !oideq(&one->oid, &two->oid)) {
 		const unsigned hexsz = the_hash_algo->hexsz;
-		int abbrev = o->flags.full_index ? hexsz : DEFAULT_ABBREV;
+		int abbrev = o->abbrev ? o->abbrev : DEFAULT_ABBREV;
+
+		if (o->flags.full_index)
+			abbrev = hexsz;
 
 		if (o->flags.binary) {
 			mmfile_t mf;
@@ -6044,6 +6047,8 @@
 	struct patch_id_t *data = priv;
 	int new_len;
 
+	if (len > 12 && starts_with(line, "\\ "))
+		return;
 	new_len = remove_space(line, len);
 
 	the_hash_algo->update_fn(data->ctx, line, new_len);
diff --git a/dir.c b/dir.c
index fe64be3..3018a65 100644
--- a/dir.c
+++ b/dir.c
@@ -54,6 +54,11 @@
 static int resolve_dtype(int dtype, struct index_state *istate,
 			 const char *path, int len);
 
+void dir_init(struct dir_struct *dir)
+{
+	memset(dir, 0, sizeof(*dir));
+}
+
 int count_slashes(const char *s)
 {
 	int cnt = 0;
@@ -916,6 +921,8 @@
 		free(pl->patterns[i]);
 	free(pl->patterns);
 	free(pl->filebuf);
+	hashmap_free_entries(&pl->recursive_hashmap, struct pattern_entry, ent);
+	hashmap_free_entries(&pl->parent_hashmap, struct pattern_entry, ent);
 
 	memset(pl, 0, sizeof(*pl));
 }
@@ -1792,9 +1799,12 @@
 		nested_repo = is_nonbare_repository_dir(&sb);
 		strbuf_release(&sb);
 	}
-	if (nested_repo)
-		return ((dir->flags & DIR_SKIP_NESTED_GIT) ? path_none :
-			(excluded ? path_excluded : path_untracked));
+	if (nested_repo) {
+		if ((dir->flags & DIR_SKIP_NESTED_GIT) ||
+		    (matches_how == MATCHED_RECURSIVELY_LEADING_PATHSPEC))
+			return path_none;
+		return excluded ? path_excluded : path_untracked;
+	}
 
 	if (!(dir->flags & DIR_SHOW_OTHER_DIRECTORIES)) {
 		if (excluded &&
@@ -3009,10 +3019,10 @@
 }
 
 /*
- * Frees memory within dir which was allocated for exclude lists and
- * the exclude_stack.  Does not free dir itself.
+ * Frees memory within dir which was allocated, and resets fields for further
+ * use.  Does not free dir itself.
  */
-void clear_directory(struct dir_struct *dir)
+void dir_clear(struct dir_struct *dir)
 {
 	int i, j;
 	struct exclude_list_group *group;
@@ -3030,6 +3040,13 @@
 		free(group->pl);
 	}
 
+	for (i = 0; i < dir->ignored_nr; i++)
+		free(dir->ignored[i]);
+	for (i = 0; i < dir->nr; i++)
+		free(dir->entries[i]);
+	free(dir->ignored);
+	free(dir->entries);
+
 	stk = dir->exclude_stack;
 	while (stk) {
 		struct exclude_stack *prev = stk->prev;
@@ -3037,6 +3054,8 @@
 		stk = prev;
 	}
 	strbuf_release(&dir->basebuf);
+
+	dir_init(dir);
 }
 
 struct ondisk_untracked_cache {
diff --git a/dir.h b/dir.h
index 5855c06..a3c40de 100644
--- a/dir.h
+++ b/dir.h
@@ -19,24 +19,23 @@
  * CE_SKIP_WORKTREE marked. If you want to exclude files, make sure you have
  * loaded the index first.
  *
- * - Prepare `struct dir_struct dir` and clear it with `memset(&dir, 0,
- * sizeof(dir))`.
+ * - Prepare `struct dir_struct dir` using `dir_init()` function.
  *
  * - To add single exclude pattern, call `add_pattern_list()` and then
  *   `add_pattern()`.
  *
  * - To add patterns from a file (e.g. `.git/info/exclude`), call
- *   `add_patterns_from_file()` , and/or set `dir.exclude_per_dir`.  A
- *   short-hand function `setup_standard_excludes()` can be used to set
- *   up the standard set of exclude settings.
+ *   `add_patterns_from_file()` , and/or set `dir.exclude_per_dir`.
  *
- * - Set options described in the Data Structure section above.
+ * - A short-hand function `setup_standard_excludes()` can be used to set
+ *   up the standard set of exclude settings, instead of manually calling
+ *   the add_pattern*() family of functions.
  *
- * - Call `read_directory()`.
+ * - Call `fill_directory()`.
  *
- * - Use `dir.entries[]`.
+ * - Use `dir.entries[]` and `dir.ignored[]`.
  *
- * - Call `clear_directory()` when none of the contained elements are no longer in use.
+ * - Call `dir_clear()` when the contained elements are no longer in use.
  *
  */
 
@@ -362,6 +361,8 @@
 int report_path_error(const char *ps_matched, const struct pathspec *pathspec);
 int within_depth(const char *name, int namelen, int depth, int max_depth);
 
+void dir_init(struct dir_struct *dir);
+
 int fill_directory(struct dir_struct *dir,
 		   struct index_state *istate,
 		   const struct pathspec *pathspec);
@@ -428,7 +429,7 @@
 void add_pattern(const char *string, const char *base,
 		 int baselen, struct pattern_list *pl, int srcpos);
 void clear_pattern_list(struct pattern_list *pl);
-void clear_directory(struct dir_struct *dir);
+void dir_clear(struct dir_struct *dir);
 
 int repo_file_exists(struct repository *repo, const char *path);
 int file_exists(const char *);
diff --git a/editor.c b/editor.c
index 91989ee..6303ae0 100644
--- a/editor.c
+++ b/editor.c
@@ -40,7 +40,7 @@
 	const char *editor = getenv("GIT_SEQUENCE_EDITOR");
 
 	if (!editor)
-		git_config_get_string_const("sequence.editor", &editor);
+		git_config_get_string_tmp("sequence.editor", &editor);
 	if (!editor)
 		editor = git_editor();
 
diff --git a/entry.c b/entry.c
index 449bd32..a0532f1 100644
--- a/entry.c
+++ b/entry.c
@@ -510,8 +510,6 @@
 			/* If it is a gitlink, leave it alone! */
 			if (S_ISGITLINK(ce->ce_mode))
 				return 0;
-			if (!state->force)
-				return error("%s is a directory", path.buf);
 			remove_subtree(&path);
 		} else if (unlink(path.buf))
 			return error_errno("unable to unlink old '%s'", path.buf);
diff --git a/environment.c b/environment.c
index 52e0c97..bb518c6 100644
--- a/environment.c
+++ b/environment.c
@@ -35,8 +35,8 @@
 int repository_format_worktree_config;
 const char *git_commit_encoding;
 const char *git_log_output_encoding;
-const char *apply_default_whitespace;
-const char *apply_default_ignorewhitespace;
+char *apply_default_whitespace;
+char *apply_default_ignorewhitespace;
 const char *git_attributes_file;
 const char *git_hooks_path;
 int zlib_compression_level = Z_BEST_SPEED;
diff --git a/fast-import.c b/fast-import.c
index ce47794..c45fe74 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -526,14 +526,6 @@
 	return r;
 }
 
-static char *pool_strdup(const char *s)
-{
-	size_t len = strlen(s) + 1;
-	char *r = mem_pool_alloc(&fi_mem_pool, len);
-	memcpy(r, s, len);
-	return r;
-}
-
 static void insert_mark(struct mark_set *s, uintmax_t idnum, struct object_entry *oe)
 {
 	while ((idnum >> s->shift) >= 1024) {
@@ -615,7 +607,7 @@
 		die("Branch name doesn't conform to GIT standards: %s", name);
 
 	b = mem_pool_calloc(&fi_mem_pool, 1, sizeof(struct branch));
-	b->name = pool_strdup(name);
+	b->name = mem_pool_strdup(&fi_mem_pool, name);
 	b->table_next_branch = branch_table[hc];
 	b->branch_tree.versions[0].mode = S_IFDIR;
 	b->branch_tree.versions[1].mode = S_IFDIR;
@@ -2806,7 +2798,7 @@
 
 	t = mem_pool_alloc(&fi_mem_pool, sizeof(struct tag));
 	memset(t, 0, sizeof(struct tag));
-	t->name = pool_strdup(arg);
+	t->name = mem_pool_strdup(&fi_mem_pool, arg);
 	if (last_tag)
 		last_tag->next_tag = t;
 	else
diff --git a/fetch-pack.c b/fetch-pack.c
index 0f1a84c..5eb6ed6 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -870,13 +870,16 @@
 			 * have this responsibility.
 			 */
 			args->check_self_contained_and_connected = 0;
-		/*
-		 * If we're obtaining the filename of a lockfile, we'll use
-		 * that filename to write a .promisor file with more
-		 * information below. If not, we need index-pack to do it for
-		 * us.
-		 */
-		if (!(do_keep && pack_lockfiles) && args->from_promisor)
+
+		if (args->from_promisor)
+			/*
+			 * write_promisor_file() may be called afterwards but
+			 * we still need index-pack to know that this is a
+			 * promisor pack. For example, if transfer.fsckobjects
+			 * is true, index-pack needs to know that .gitmodules
+			 * is a promisor object (so that it won't complain if
+			 * it is missing).
+			 */
 			strvec_push(&cmd.args, "--promisor");
 	}
 	else {
diff --git a/git-bisect.sh b/git-bisect.sh
index f03fbb1..c28e35b 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -4,7 +4,7 @@
 LONG_USAGE='git bisect help
 	print this long help message.
 git bisect start [--term-{old,good}=<term> --term-{new,bad}=<term>]
-		 [--no-checkout] [<bad> [<good>...]] [--] [<pathspec>...]
+		 [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<pathspec>...]
 	reset bisect state and start bisection.
 git bisect (bad|new) [<rev>]
 	mark <rev> a known-bad revision/
@@ -153,7 +153,7 @@
 	git bisect--helper --bisect-next-check $TERM_GOOD $TERM_BAD $TERM_GOOD|| exit
 
 	# Perform all bisection computation, display and checkout
-	git bisect--helper --next-all $(git rev-parse --verify -q BISECT_HEAD > /dev/null && echo --no-checkout)
+	git bisect--helper --next-all
 	res=$?
 
 	# Check if we should exit because bisection is finished
diff --git a/git-compat-util.h b/git-compat-util.h
index 5637114..7a0fb7a 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -252,8 +252,10 @@
 #ifdef PRECOMPOSE_UNICODE
 #include "compat/precompose_utf8.h"
 #else
-#define precompose_str(in,i_nfd2nfc)
-#define precompose_argv(c,v)
+static inline void precompose_argv(int argc, const char **argv)
+{
+	; /* nothing */
+}
 #define probe_utf8_pathname_composition()
 #endif
 
@@ -270,7 +272,9 @@
 #endif
 
 #ifdef NO_SETITIMER
-#define setitimer(which,value,ovalue)
+static inline int setitimer(int which, const struct itimerval *value, struct itimerval *newvalue) {
+	; /* nothing */
+}
 #endif
 
 #ifndef NO_LIBGEN_H
@@ -1231,8 +1235,14 @@
 #endif
 
 #ifndef _POSIX_THREAD_SAFE_FUNCTIONS
-#define flockfile(fh)
-#define funlockfile(fh)
+static inline void flockfile(FILE *fh)
+{
+	; /* nothing */
+}
+static inline void funlockfile(FILE *fh)
+{
+	; /* nothing */
+}
 #define getc_unlocked(fh) getc(fh)
 #endif
 
diff --git a/git-mergetool--lib.sh b/git-mergetool--lib.sh
index 204a5ac..2defef2 100644
--- a/git-mergetool--lib.sh
+++ b/git-mergetool--lib.sh
@@ -43,7 +43,14 @@
 
 	shown_any=
 	( cd "$MERGE_TOOLS_DIR" && ls ) | {
-		while read toolname
+		while read scriptname
+		do
+			setup_tool "$scriptname" 2>/dev/null
+			variants="$variants$(list_tool_variants)\n"
+		done
+		variants="$(echo "$variants" | sort | uniq)"
+
+		for toolname in $variants
 		do
 			if setup_tool "$toolname" 2>/dev/null &&
 				(eval "$condition" "$toolname")
@@ -157,6 +164,10 @@
 		echo "$1"
 	}
 
+	list_tool_variants () {
+		echo "$tool"
+	}
+
 	# Most tools' exit codes cannot be trusted, so By default we ignore
 	# their exit code and check the merged file's modification time in
 	# check_unchanged() to determine whether or not the merge was
@@ -178,19 +189,26 @@
 		false
 	}
 
-
-	if ! test -f "$MERGE_TOOLS_DIR/$tool"
+	if test -f "$MERGE_TOOLS_DIR/$tool"
 	then
+		. "$MERGE_TOOLS_DIR/$tool"
+	elif test -f "$MERGE_TOOLS_DIR/${tool%[0-9]}"
+	then
+		. "$MERGE_TOOLS_DIR/${tool%[0-9]}"
+	else
 		setup_user_tool
 		return $?
 	fi
 
-	# Load the redefined functions
-	. "$MERGE_TOOLS_DIR/$tool"
 	# Now let the user override the default command for the tool.  If
 	# they have not done so then this will return 1 which we ignore.
 	setup_user_tool
 
+	if ! list_tool_variants | grep -q "^$tool$"
+	then
+		return 1
+	fi
+
 	if merge_mode && ! can_merge
 	then
 		echo "error: '$tool' can not be used to resolve merges" >&2
@@ -286,11 +304,14 @@
 		tools="$tools smerge"
 	fi
 	case "${VISUAL:-$EDITOR}" in
+	*nvim*)
+		tools="$tools nvimdiff vimdiff emerge"
+		;;
 	*vim*)
-		tools="$tools vimdiff emerge"
+		tools="$tools vimdiff nvimdiff emerge"
 		;;
 	*)
-		tools="$tools emerge vimdiff"
+		tools="$tools emerge vimdiff nvimdiff"
 		;;
 	esac
 }
diff --git a/git-rebase--preserve-merges.sh b/git-rebase--preserve-merges.sh
index dec90e9..b9c71d2 100644
--- a/git-rebase--preserve-merges.sh
+++ b/git-rebase--preserve-merges.sh
@@ -193,16 +193,6 @@
 	fi
 }
 
-# Put the last action marked done at the beginning of the todo list
-# again. If there has not been an action marked done yet, leave the list of
-# items on the todo list unchanged.
-reschedule_last_action () {
-	tail -n 1 "$done" | cat - "$todo" >"$todo".new
-	sed -e \$d <"$done" >"$done".new
-	mv -f "$todo".new "$todo"
-	mv -f "$done".new "$done"
-}
-
 append_todo_help () {
 	gettext "
 Commands:
diff --git a/git-send-email.perl b/git-send-email.perl
index 36c47ba..1f425c0 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -250,6 +250,7 @@
 my $use_xmailer = 1;
 my $validate = 1;
 my $target_xfer_encoding = 'auto';
+my $forbid_sendmail_variables = 1;
 
 my %config_bool_settings = (
     "thread" => \$thread,
@@ -263,6 +264,7 @@
     "multiedit" => \$multiedit,
     "annotate" => \$annotate,
     "xmailer" => \$use_xmailer,
+    "forbidsendmailvariables" => \$forbid_sendmail_variables,
 );
 
 my %config_settings = (
@@ -478,6 +480,12 @@
     usage();
 }
 
+if ($forbid_sendmail_variables && (scalar Git::config_regexp("^sendmail[.]")) != 0) {
+	die __("fatal: found configuration options for 'sendmail'\n" .
+		"git-send-email is configured with the sendemail.* options - note the 'e'.\n" .
+		"Set sendemail.forbidSendmailVariables to false to disable this check.\n");
+}
+
 die __("Cannot run git format-patch from outside a repository\n")
 	if $format_patch and not $repo;
 
diff --git a/help.c b/help.c
index d478afb..4e2468a 100644
--- a/help.c
+++ b/help.c
@@ -375,7 +375,7 @@
 {
 	const char *cmd_list;
 
-	if (git_config_get_string_const("completion.commands", &cmd_list))
+	if (git_config_get_string_tmp("completion.commands", &cmd_list))
 		return;
 
 	string_list_sort(list);
diff --git a/ident.c b/ident.c
index e666ee4..6aba4b5 100644
--- a/ident.c
+++ b/ident.c
@@ -345,27 +345,45 @@
 	return 0;
 }
 
-static const char *env_hint =
-N_("\n"
-   "*** Please tell me who you are.\n"
-   "\n"
-   "Run\n"
-   "\n"
-   "  git config --global user.email \"you@example.com\"\n"
-   "  git config --global user.name \"Your Name\"\n"
-   "\n"
-   "to set your account\'s default identity.\n"
-   "Omit --global to set the identity only in this repository.\n"
-   "\n");
+
+static void ident_env_hint(enum want_ident whose_ident)
+{
+	switch (whose_ident) {
+	case WANT_AUTHOR_IDENT:
+		fputs(_("Author identity unknown\n"), stderr);
+		break;
+	case WANT_COMMITTER_IDENT:
+		fputs(_("Committer identity unknown\n"), stderr);
+		break;
+	default:
+		break;
+	}
+
+	fputs(_("\n"
+		"*** Please tell me who you are.\n"
+		"\n"
+		"Run\n"
+		"\n"
+		"  git config --global user.email \"you@example.com\"\n"
+		"  git config --global user.name \"Your Name\"\n"
+		"\n"
+		"to set your account\'s default identity.\n"
+		"Omit --global to set the identity only in this repository.\n"
+		"\n"), stderr);
+}
 
 const char *fmt_ident(const char *name, const char *email,
 		      enum want_ident whose_ident, const char *date_str, int flag)
 {
-	static struct strbuf ident = STRBUF_INIT;
+	static int index;
+	static struct strbuf ident_pool[2] = { STRBUF_INIT, STRBUF_INIT };
 	int strict = (flag & IDENT_STRICT);
 	int want_date = !(flag & IDENT_NO_DATE);
 	int want_name = !(flag & IDENT_NO_NAME);
 
+	struct strbuf *ident = &ident_pool[index];
+	index = (index + 1) % ARRAY_SIZE(ident_pool);
+
 	if (!email) {
 		if (whose_ident == WANT_AUTHOR_IDENT && git_author_email.len)
 			email = git_author_email.buf;
@@ -375,12 +393,12 @@
 	if (!email) {
 		if (strict && ident_use_config_only
 		    && !(ident_config_given & IDENT_MAIL_GIVEN)) {
-			fputs(_(env_hint), stderr);
+			ident_env_hint(whose_ident);
 			die(_("no email was given and auto-detection is disabled"));
 		}
 		email = ident_default_email();
 		if (strict && default_email_is_bogus) {
-			fputs(_(env_hint), stderr);
+			ident_env_hint(whose_ident);
 			die(_("unable to auto-detect email address (got '%s')"), email);
 		}
 	}
@@ -397,13 +415,13 @@
 		if (!name) {
 			if (strict && ident_use_config_only
 			    && !(ident_config_given & IDENT_NAME_GIVEN)) {
-				fputs(_(env_hint), stderr);
+				ident_env_hint(whose_ident);
 				die(_("no name was given and auto-detection is disabled"));
 			}
 			name = ident_default_name();
 			using_default = 1;
 			if (strict && default_name_is_bogus) {
-				fputs(_(env_hint), stderr);
+				ident_env_hint(whose_ident);
 				die(_("unable to auto-detect name (got '%s')"), name);
 			}
 		}
@@ -411,7 +429,7 @@
 			struct passwd *pw;
 			if (strict) {
 				if (using_default)
-					fputs(_(env_hint), stderr);
+					ident_env_hint(whose_ident);
 				die(_("empty ident name (for <%s>) not allowed"), email);
 			}
 			pw = xgetpwuid_self(NULL);
@@ -421,25 +439,25 @@
 			die(_("name consists only of disallowed characters: %s"), name);
 	}
 
-	strbuf_reset(&ident);
+	strbuf_reset(ident);
 	if (want_name) {
-		strbuf_addstr_without_crud(&ident, name);
-		strbuf_addstr(&ident, " <");
+		strbuf_addstr_without_crud(ident, name);
+		strbuf_addstr(ident, " <");
 	}
-	strbuf_addstr_without_crud(&ident, email);
+	strbuf_addstr_without_crud(ident, email);
 	if (want_name)
-			strbuf_addch(&ident, '>');
+		strbuf_addch(ident, '>');
 	if (want_date) {
-		strbuf_addch(&ident, ' ');
+		strbuf_addch(ident, ' ');
 		if (date_str && date_str[0]) {
-			if (parse_date(date_str, &ident) < 0)
+			if (parse_date(date_str, ident) < 0)
 				die(_("invalid date format: %s"), date_str);
 		}
 		else
-			strbuf_addstr(&ident, ident_default_date());
+			strbuf_addstr(ident, ident_default_date());
 	}
 
-	return ident.buf;
+	return ident->buf;
 }
 
 const char *fmt_name(enum want_ident whose_ident)
diff --git a/mem-pool.c b/mem-pool.c
index a2841a4..8401761 100644
--- a/mem-pool.c
+++ b/mem-pool.c
@@ -12,11 +12,13 @@
  * `insert_after`. If `insert_after` is NULL, then insert block at the
  * head of the linked list.
  */
-static struct mp_block *mem_pool_alloc_block(struct mem_pool *mem_pool, size_t block_alloc, struct mp_block *insert_after)
+static struct mp_block *mem_pool_alloc_block(struct mem_pool *pool,
+					     size_t block_alloc,
+					     struct mp_block *insert_after)
 {
 	struct mp_block *p;
 
-	mem_pool->pool_alloc += sizeof(struct mp_block) + block_alloc;
+	pool->pool_alloc += sizeof(struct mp_block) + block_alloc;
 	p = xmalloc(st_add(sizeof(struct mp_block), block_alloc));
 
 	p->next_free = (char *)p->space;
@@ -26,35 +28,27 @@
 		p->next_block = insert_after->next_block;
 		insert_after->next_block = p;
 	} else {
-		p->next_block = mem_pool->mp_block;
-		mem_pool->mp_block = p;
+		p->next_block = pool->mp_block;
+		pool->mp_block = p;
 	}
 
 	return p;
 }
 
-void mem_pool_init(struct mem_pool **mem_pool, size_t initial_size)
+void mem_pool_init(struct mem_pool *pool, size_t initial_size)
 {
-	struct mem_pool *pool;
-
-	if (*mem_pool)
-		return;
-
-	pool = xcalloc(1, sizeof(*pool));
-
+	memset(pool, 0, sizeof(*pool));
 	pool->block_alloc = BLOCK_GROWTH_SIZE;
 
 	if (initial_size > 0)
 		mem_pool_alloc_block(pool, initial_size, NULL);
-
-	*mem_pool = pool;
 }
 
-void mem_pool_discard(struct mem_pool *mem_pool, int invalidate_memory)
+void mem_pool_discard(struct mem_pool *pool, int invalidate_memory)
 {
 	struct mp_block *block, *block_to_free;
 
-	block = mem_pool->mp_block;
+	block = pool->mp_block;
 	while (block)
 	{
 		block_to_free = block;
@@ -66,10 +60,11 @@
 		free(block_to_free);
 	}
 
-	free(mem_pool);
+	pool->mp_block = NULL;
+	pool->pool_alloc = 0;
 }
 
-void *mem_pool_alloc(struct mem_pool *mem_pool, size_t len)
+void *mem_pool_alloc(struct mem_pool *pool, size_t len)
 {
 	struct mp_block *p = NULL;
 	void *r;
@@ -78,15 +73,15 @@
 	if (len & (sizeof(uintmax_t) - 1))
 		len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
 
-	if (mem_pool->mp_block &&
-	    mem_pool->mp_block->end - mem_pool->mp_block->next_free >= len)
-		p = mem_pool->mp_block;
+	if (pool->mp_block &&
+	    pool->mp_block->end - pool->mp_block->next_free >= len)
+		p = pool->mp_block;
 
 	if (!p) {
-		if (len >= (mem_pool->block_alloc / 2))
-			return mem_pool_alloc_block(mem_pool, len, mem_pool->mp_block);
+		if (len >= (pool->block_alloc / 2))
+			return mem_pool_alloc_block(pool, len, pool->mp_block);
 
-		p = mem_pool_alloc_block(mem_pool, mem_pool->block_alloc, NULL);
+		p = mem_pool_alloc_block(pool, pool->block_alloc, NULL);
 	}
 
 	r = p->next_free;
@@ -94,20 +89,38 @@
 	return r;
 }
 
-void *mem_pool_calloc(struct mem_pool *mem_pool, size_t count, size_t size)
+void *mem_pool_calloc(struct mem_pool *pool, size_t count, size_t size)
 {
 	size_t len = st_mult(count, size);
-	void *r = mem_pool_alloc(mem_pool, len);
+	void *r = mem_pool_alloc(pool, len);
 	memset(r, 0, len);
 	return r;
 }
 
-int mem_pool_contains(struct mem_pool *mem_pool, void *mem)
+char *mem_pool_strdup(struct mem_pool *pool, const char *str)
+{
+	size_t len = strlen(str) + 1;
+	char *ret = mem_pool_alloc(pool, len);
+
+	return memcpy(ret, str, len);
+}
+
+char *mem_pool_strndup(struct mem_pool *pool, const char *str, size_t len)
+{
+	char *p = memchr(str, '\0', len);
+	size_t actual_len = (p ? p - str : len);
+	char *ret = mem_pool_alloc(pool, actual_len+1);
+
+	ret[actual_len] = '\0';
+	return memcpy(ret, str, actual_len);
+}
+
+int mem_pool_contains(struct mem_pool *pool, void *mem)
 {
 	struct mp_block *p;
 
 	/* Check if memory is allocated in a block */
-	for (p = mem_pool->mp_block; p; p = p->next_block)
+	for (p = pool->mp_block; p; p = p->next_block)
 		if ((mem >= ((void *)p->space)) &&
 		    (mem < ((void *)p->end)))
 			return 1;
diff --git a/mem-pool.h b/mem-pool.h
index 999d3c3..fe7507f 100644
--- a/mem-pool.h
+++ b/mem-pool.h
@@ -24,12 +24,12 @@
 /*
  * Initialize mem_pool with specified initial size.
  */
-void mem_pool_init(struct mem_pool **mem_pool, size_t initial_size);
+void mem_pool_init(struct mem_pool *pool, size_t initial_size);
 
 /*
- * Discard a memory pool and free all the memory it is responsible for.
+ * Discard all the memory the memory pool is responsible for.
  */
-void mem_pool_discard(struct mem_pool *mem_pool, int invalidate_memory);
+void mem_pool_discard(struct mem_pool *pool, int invalidate_memory);
 
 /*
  * Alloc memory from the mem_pool.
@@ -42,6 +42,12 @@
 void *mem_pool_calloc(struct mem_pool *pool, size_t count, size_t size);
 
 /*
+ * Allocate memory from the memory pool and copy str into it.
+ */
+char *mem_pool_strdup(struct mem_pool *pool, const char *str);
+char *mem_pool_strndup(struct mem_pool *pool, const char *str, size_t len);
+
+/*
  * Move the memory associated with the 'src' pool to the 'dst' pool. The 'src'
  * pool will be empty and not contain any memory. It still needs to be free'd
  * with a call to `mem_pool_discard`.
@@ -52,6 +58,6 @@
  * Check if a memory pointed at by 'mem' is part of the range of
  * memory managed by the specified mem_pool.
  */
-int mem_pool_contains(struct mem_pool *mem_pool, void *mem);
+int mem_pool_contains(struct mem_pool *pool, void *mem);
 
 #endif
diff --git a/merge.c b/merge.c
index 753e461..5fb88af 100644
--- a/merge.c
+++ b/merge.c
@@ -80,8 +80,8 @@
 	}
 
 	memset(&opts, 0, sizeof(opts));
+	dir_init(&dir);
 	if (overwrite_ignore) {
-		memset(&dir, 0, sizeof(dir));
 		dir.flags |= DIR_SHOW_IGNORED;
 		setup_standard_excludes(&dir);
 		opts.dir = &dir;
@@ -102,6 +102,7 @@
 		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/mergetools/bc b/mergetools/bc
index 3a69e60..a89086e 100644
--- a/mergetools/bc
+++ b/mergetools/bc
@@ -21,3 +21,8 @@
 		echo bcompare
 	fi
 }
+
+list_tool_variants () {
+	echo bc
+	echo bc3
+}
diff --git a/mergetools/bc3 b/mergetools/bc3
deleted file mode 100644
index 5d8dd48..0000000
--- a/mergetools/bc3
+++ /dev/null
@@ -1 +0,0 @@
-. "$MERGE_TOOLS_DIR/bc"
diff --git a/mergetools/gvimdiff3 b/mergetools/gvimdiff3
deleted file mode 100644
index 04a5bb0..0000000
--- a/mergetools/gvimdiff3
+++ /dev/null
@@ -1 +0,0 @@
-. "$MERGE_TOOLS_DIR/vimdiff"
diff --git a/mergetools/gvimdiff2 b/mergetools/nvimdiff
similarity index 100%
rename from mergetools/gvimdiff2
rename to mergetools/nvimdiff
diff --git a/mergetools/vimdiff b/mergetools/vimdiff
index 10d86f3..abc8ce4 100644
--- a/mergetools/vimdiff
+++ b/mergetools/vimdiff
@@ -5,7 +5,7 @@
 
 merge_cmd () {
 	case "$1" in
-	gvimdiff|vimdiff)
+	*vimdiff)
 		if $base_present
 		then
 			"$merge_tool_path" -f -d -c '4wincmd w | wincmd J' \
@@ -15,11 +15,11 @@
 				"$LOCAL" "$MERGED" "$REMOTE"
 		fi
 		;;
-	gvimdiff2|vimdiff2)
+	*vimdiff2)
 		"$merge_tool_path" -f -d -c 'wincmd l' \
 			"$LOCAL" "$MERGED" "$REMOTE"
 		;;
-	gvimdiff3|vimdiff3)
+	*vimdiff3)
 		if $base_present
 		then
 			"$merge_tool_path" -f -d -c 'hid | hid | hid' \
@@ -34,10 +34,13 @@
 
 translate_merge_tool_path() {
 	case "$1" in
-	gvimdiff|gvimdiff2|gvimdiff3)
+	nvimdiff*)
+		echo nvim
+		;;
+	gvimdiff*)
 		echo gvim
 		;;
-	vimdiff|vimdiff2|vimdiff3)
+	vimdiff*)
 		echo vim
 		;;
 	esac
@@ -46,3 +49,11 @@
 exit_code_trustable () {
 	true
 }
+
+list_tool_variants () {
+	for prefix in '' g n; do
+		for suffix in '' 2 3; do
+			echo "${prefix}vimdiff${suffix}"
+		done
+	done
+}
diff --git a/mergetools/vimdiff2 b/mergetools/vimdiff2
deleted file mode 100644
index 04a5bb0..0000000
--- a/mergetools/vimdiff2
+++ /dev/null
@@ -1 +0,0 @@
-. "$MERGE_TOOLS_DIR/vimdiff"
diff --git a/mergetools/vimdiff3 b/mergetools/vimdiff3
deleted file mode 100644
index 04a5bb0..0000000
--- a/mergetools/vimdiff3
+++ /dev/null
@@ -1 +0,0 @@
-. "$MERGE_TOOLS_DIR/vimdiff"
diff --git a/midx.c b/midx.c
index a5fb797..e9b2e12 100644
--- a/midx.c
+++ b/midx.c
@@ -17,7 +17,6 @@
 #define MIDX_BYTE_HASH_VERSION 5
 #define MIDX_BYTE_NUM_CHUNKS 6
 #define MIDX_BYTE_NUM_PACKS 8
-#define MIDX_HASH_VERSION 1
 #define MIDX_HEADER_SIZE 12
 #define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + the_hash_algo->rawsz)
 
@@ -36,6 +35,18 @@
 
 #define PACK_EXPIRED UINT_MAX
 
+static uint8_t oid_version(void)
+{
+	switch (hash_algo_by_ptr(the_hash_algo)) {
+	case GIT_HASH_SHA1:
+		return 1;
+	case GIT_HASH_SHA256:
+		return 2;
+	default:
+		die(_("invalid hash version"));
+	}
+}
+
 static char *get_midx_filename(const char *object_dir)
 {
 	return xstrfmt("%s/pack/multi-pack-index", object_dir);
@@ -90,8 +101,11 @@
 		      m->version);
 
 	hash_version = m->data[MIDX_BYTE_HASH_VERSION];
-	if (hash_version != MIDX_HASH_VERSION)
-		die(_("hash version %u does not match"), hash_version);
+	if (hash_version != oid_version()) {
+		error(_("multi-pack-index hash version %u does not match version %u"),
+		      hash_version, oid_version());
+		goto cleanup_fail;
+	}
 	m->hash_len = the_hash_algo->rawsz;
 
 	m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
@@ -418,7 +432,7 @@
 
 	hashwrite_be32(f, MIDX_SIGNATURE);
 	byte_values[0] = MIDX_VERSION;
-	byte_values[1] = MIDX_HASH_VERSION;
+	byte_values[1] = oid_version();
 	byte_values[2] = num_chunks;
 	byte_values[3] = 0; /* unused */
 	hashwrite(f, byte_values, sizeof(byte_values));
@@ -807,11 +821,9 @@
 	int result = 0;
 
 	midx_name = get_midx_filename(object_dir);
-	if (safe_create_leading_directories(midx_name)) {
-		UNLEAK(midx_name);
+	if (safe_create_leading_directories(midx_name))
 		die_errno(_("unable to create leading directories of %s"),
 			  midx_name);
-	}
 
 	if (m)
 		packs.m = m;
@@ -1051,10 +1063,8 @@
 		r->objects->multi_pack_index = NULL;
 	}
 
-	if (remove_path(midx)) {
-		UNLEAK(midx);
+	if (remove_path(midx))
 		die(_("failed to clear multi-pack-index at %s"), midx);
-	}
 
 	free(midx);
 }
@@ -1105,8 +1115,17 @@
 	struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
 	verify_midx_error = 0;
 
-	if (!m)
-		return 0;
+	if (!m) {
+		int result = 0;
+		struct stat sb;
+		char *filename = get_midx_filename(object_dir);
+		if (!stat(filename, &sb)) {
+			error(_("multi-pack-index file exists, but failed to parse"));
+			result = 1;
+		}
+		free(filename);
+		return result;
+	}
 
 	if (flags & MIDX_PROGRESS)
 		progress = start_progress(_("Looking for referenced packfiles"),
@@ -1371,7 +1390,7 @@
 
 	free(pack_info);
 
-	if (total_size < batch_size || packs_to_repack < 2)
+	if (packs_to_repack < 2)
 		return 1;
 
 	return 0;
@@ -1383,6 +1402,7 @@
 	uint32_t i;
 	unsigned char *include_pack;
 	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);
 
@@ -1435,6 +1455,8 @@
 		goto cleanup;
 	}
 
+	cmd_in = xfdopen(cmd.in, "w");
+
 	for (i = 0; i < m->num_objects; i++) {
 		struct object_id oid;
 		uint32_t pack_int_id = nth_midxed_pack_int_id(m, i);
@@ -1443,10 +1465,9 @@
 			continue;
 
 		nth_midxed_object_oid(&oid, m, i);
-		xwrite(cmd.in, oid_to_hex(&oid), the_hash_algo->hexsz);
-		xwrite(cmd.in, "\n", 1);
+		fprintf(cmd_in, "%s\n", oid_to_hex(&oid));
 	}
-	close(cmd.in);
+	fclose(cmd_in);
 
 	if (finish_command(&cmd)) {
 		error(_("could not finish pack-objects"));
diff --git a/parse-options.c b/parse-options.c
index c57618d..f050743 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -525,7 +525,8 @@
 	parse_options_start_1(ctx, argc, argv, prefix, options, flags);
 }
 
-static void show_negated_gitcomp(const struct option *opts, int nr_noopts)
+static void show_negated_gitcomp(const struct option *opts, int show_all,
+				 int nr_noopts)
 {
 	int printed_dashdash = 0;
 
@@ -535,7 +536,8 @@
 
 		if (!opts->long_name)
 			continue;
-		if (opts->flags & (PARSE_OPT_HIDDEN | PARSE_OPT_NOCOMPLETE))
+		if (!show_all &&
+			(opts->flags & (PARSE_OPT_HIDDEN | PARSE_OPT_NOCOMPLETE)))
 			continue;
 		if (opts->flags & PARSE_OPT_NONEG)
 			continue;
@@ -572,7 +574,7 @@
 	}
 }
 
-static int show_gitcomp(const struct option *opts)
+static int show_gitcomp(const struct option *opts, int show_all)
 {
 	const struct option *original_opts = opts;
 	int nr_noopts = 0;
@@ -582,7 +584,8 @@
 
 		if (!opts->long_name)
 			continue;
-		if (opts->flags & (PARSE_OPT_HIDDEN | PARSE_OPT_NOCOMPLETE))
+		if (!show_all &&
+			(opts->flags & (PARSE_OPT_HIDDEN | PARSE_OPT_NOCOMPLETE)))
 			continue;
 
 		switch (opts->type) {
@@ -610,8 +613,8 @@
 			nr_noopts++;
 		printf(" --%s%s", opts->long_name, suffix);
 	}
-	show_negated_gitcomp(original_opts, -1);
-	show_negated_gitcomp(original_opts, nr_noopts);
+	show_negated_gitcomp(original_opts, show_all, -1);
+	show_negated_gitcomp(original_opts, show_all, nr_noopts);
 	fputc('\n', stdout);
 	return PARSE_OPT_COMPLETE;
 }
@@ -723,9 +726,14 @@
 		if (internal_help && ctx->total == 1 && !strcmp(arg + 1, "h"))
 			goto show_usage;
 
-		/* lone --git-completion-helper is asked by git-completion.bash */
-		if (ctx->total == 1 && !strcmp(arg + 1, "-git-completion-helper"))
-			return show_gitcomp(options);
+		/*
+		 * lone --git-completion-helper and --git-completion-helper-all
+		 * are asked by git-completion.bash
+		 */
+		if (ctx->total == 1 && !strcmp(arg, "--git-completion-helper"))
+			return show_gitcomp(options, 0);
+		if (ctx->total == 1 && !strcmp(arg, "--git-completion-helper-all"))
+			return show_gitcomp(options, 1);
 
 		if (arg[1] != '-') {
 			ctx->opt = arg + 1;
diff --git a/parse-options.h b/parse-options.h
index 46af942..7030d8f 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -314,7 +314,7 @@
 #define OPT__FORCE(var, h, f) OPT_COUNTUP_F('f', "force",   (var), (h), (f))
 #define OPT__ABBREV(var)  \
 	{ OPTION_CALLBACK, 0, "abbrev", (var), N_("n"),	\
-	  N_("use <n> digits to display SHA-1s"),	\
+	  N_("use <n> digits to display object names"),	\
 	  PARSE_OPT_OPTARG, &parse_opt_abbrev_cb, 0 }
 #define OPT__COLOR(var, h) \
 	OPT_COLOR_FLAG(0, "color", (var), (h))
diff --git a/path.c b/path.c
index 8b2c753..7b385e5 100644
--- a/path.c
+++ b/path.c
@@ -1528,8 +1528,6 @@
 	return NULL;
 }
 
-REPO_GIT_PATH_FUNC(cherry_pick_head, "CHERRY_PICK_HEAD")
-REPO_GIT_PATH_FUNC(revert_head, "REVERT_HEAD")
 REPO_GIT_PATH_FUNC(squash_msg, "SQUASH_MSG")
 REPO_GIT_PATH_FUNC(merge_msg, "MERGE_MSG")
 REPO_GIT_PATH_FUNC(merge_rr, "MERGE_RR")
diff --git a/path.h b/path.h
index 1f1bf8f..e7e77da 100644
--- a/path.h
+++ b/path.h
@@ -170,8 +170,6 @@
 	}
 
 struct path_cache {
-	const char *cherry_pick_head;
-	const char *revert_head;
 	const char *squash_msg;
 	const char *merge_msg;
 	const char *merge_rr;
@@ -182,10 +180,11 @@
 	const char *shallow;
 };
 
-#define PATH_CACHE_INIT { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL }
+#define PATH_CACHE_INIT                                        \
+	{                                                      \
+		NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL \
+	}
 
-const char *git_path_cherry_pick_head(struct repository *r);
-const char *git_path_revert_head(struct repository *r);
 const char *git_path_squash_msg(struct repository *r);
 const char *git_path_merge_msg(struct repository *r);
 const char *git_path_merge_rr(struct repository *r);
diff --git a/perl/Git.pm b/perl/Git.pm
index 54c9ed0..10df990 100644
--- a/perl/Git.pm
+++ b/perl/Git.pm
@@ -723,6 +723,32 @@
 	return scalar _config_common({'kind' => '--int'}, @_);
 }
 
+=item config_regexp ( RE )
+
+Retrieve the list of configuration key names matching the regular
+expression C<RE>. The return value is a list of strings matching
+this regex.
+
+=cut
+
+sub config_regexp {
+	my ($self, $regex) = _maybe_self(@_);
+	try {
+		my @cmd = ('config', '--name-only', '--get-regexp', $regex);
+		unshift @cmd, $self if $self;
+		my @matches = command(@cmd);
+		return @matches;
+	} catch Git::Error::Command with {
+		my $E = shift;
+		if ($E->value() == 1) {
+			my @matches = ();
+			return @matches;
+		} else {
+			throw $E;
+		}
+	};
+}
+
 # Common subroutine to implement bulk of what the config* family of methods
 # do. This currently wraps command('config') so it is not so fast.
 sub _config_common {
diff --git a/po/fr.po b/po/fr.po
index d20fc44..75b1e75 100644
--- a/po/fr.po
+++ b/po/fr.po
@@ -6503,7 +6503,7 @@
 #: remote.c:1088
 #, c-format
 msgid "unable to delete '%s': remote ref does not exist"
-msgstr "suppression d '%s' impossible : la référence distante n'existe pas"
+msgstr "suppression de '%s' impossible : la référence distante n'existe pas"
 
 #: remote.c:1100
 #, c-format
diff --git a/progress.c b/progress.c
index 3eda914..31014e6 100644
--- a/progress.c
+++ b/progress.c
@@ -319,9 +319,12 @@
 
 void stop_progress(struct progress **p_progress)
 {
+	if (!p_progress)
+		BUG("don't provide NULL to stop_progress");
+
 	finish_if_sparse(*p_progress);
 
-	if (p_progress && *p_progress) {
+	if (*p_progress) {
 		trace2_data_intmax("progress", the_repository, "total_objects",
 				   (*p_progress)->total);
 
@@ -338,7 +341,12 @@
 
 void stop_progress_msg(struct progress **p_progress, const char *msg)
 {
-	struct progress *progress = *p_progress;
+	struct progress *progress;
+
+	if (!p_progress)
+		BUG("don't provide NULL to stop_progress_msg");
+
+	progress = *p_progress;
 	if (!progress)
 		return;
 	*p_progress = NULL;
diff --git a/protocol.c b/protocol.c
index d1dd342..8d964fc 100644
--- a/protocol.c
+++ b/protocol.c
@@ -21,7 +21,7 @@
 	const char *git_test_k = "GIT_TEST_PROTOCOL_VERSION";
 	const char *git_test_v;
 
-	if (!git_config_get_string_const("protocol.version", &value)) {
+	if (!git_config_get_string_tmp("protocol.version", &value)) {
 		enum protocol_version version = parse_protocol_version(value);
 
 		if (version == protocol_unknown_version)
diff --git a/read-cache.c b/read-cache.c
index 8ed1c29..fa291cd 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -89,8 +89,10 @@
 	else
 		pool_ptr = &istate->ce_mem_pool;
 
-	if (!*pool_ptr)
-		mem_pool_init(pool_ptr, 0);
+	if (!*pool_ptr) {
+		*pool_ptr = xmalloc(sizeof(**pool_ptr));
+		mem_pool_init(*pool_ptr, 0);
+	}
 
 	return *pool_ptr;
 }
@@ -2006,11 +2008,12 @@
 {
 	unsigned long consumed;
 
+	istate->ce_mem_pool = xmalloc(sizeof(*istate->ce_mem_pool));
 	if (istate->version == 4) {
-		mem_pool_init(&istate->ce_mem_pool,
+		mem_pool_init(istate->ce_mem_pool,
 				estimate_cache_size_from_compressed(istate->cache_nr));
 	} else {
-		mem_pool_init(&istate->ce_mem_pool,
+		mem_pool_init(istate->ce_mem_pool,
 				estimate_cache_size(mmap_size, istate->cache_nr));
 	}
 
@@ -2070,7 +2073,8 @@
 	if (istate->name_hash_initialized)
 		BUG("the name hash isn't thread safe");
 
-	mem_pool_init(&istate->ce_mem_pool, 0);
+	istate->ce_mem_pool = xmalloc(sizeof(*istate->ce_mem_pool));
+	mem_pool_init(istate->ce_mem_pool, 0);
 
 	/* ensure we have no more threads than we have blocks to process */
 	if (nr_threads > ieot->nr)
@@ -2097,11 +2101,12 @@
 		nr = 0;
 		for (j = p->ieot_start; j < p->ieot_start + p->ieot_blocks; j++)
 			nr += p->ieot->entries[j].nr;
+		istate->ce_mem_pool = xmalloc(sizeof(*istate->ce_mem_pool));
 		if (istate->version == 4) {
-			mem_pool_init(&p->ce_mem_pool,
+			mem_pool_init(p->ce_mem_pool,
 				estimate_cache_size_from_compressed(nr));
 		} else {
-			mem_pool_init(&p->ce_mem_pool,
+			mem_pool_init(p->ce_mem_pool,
 				estimate_cache_size(mmap_size, nr));
 		}
 
@@ -2358,7 +2363,7 @@
 
 	if (istate->ce_mem_pool) {
 		mem_pool_discard(istate->ce_mem_pool, should_validate_cache_entries());
-		istate->ce_mem_pool = NULL;
+		FREE_AND_NULL(istate->ce_mem_pool);
 	}
 
 	return 0;
diff --git a/ref-filter.c b/ref-filter.c
index ba85869..8ba0e31 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -345,9 +345,11 @@
 		atom->u.contents.option = C_SIG;
 	else if (!strcmp(arg, "subject"))
 		atom->u.contents.option = C_SUB;
-	else if (skip_prefix(arg, "trailers", &arg)) {
-		skip_prefix(arg, ":", &arg);
-		if (trailers_atom_parser(format, atom, *arg ? arg : NULL, err))
+	else if (!strcmp(arg, "trailers")) {
+		if (trailers_atom_parser(format, atom, NULL, err))
+			return -1;
+	} else if (skip_prefix(arg, "trailers:", &arg)) {
+		if (trailers_atom_parser(format, atom, arg, err))
 			return -1;
 	} else if (skip_prefix(arg, "lines=", &arg)) {
 		atom->u.contents.option = C_LINES;
diff --git a/refs.c b/refs.c
index 9e28912..156fdcd 100644
--- a/refs.c
+++ b/refs.c
@@ -313,7 +313,7 @@
 	return read_ref_full(refname, RESOLVE_REF_READING, oid, NULL);
 }
 
-static int refs_ref_exists(struct ref_store *refs, const char *refname)
+int refs_ref_exists(struct ref_store *refs, const char *refname)
 {
 	return !!refs_resolve_ref_unsafe(refs, refname, RESOLVE_REF_READING, NULL, NULL);
 }
@@ -708,10 +708,9 @@
 
 static int is_per_worktree_ref(const char *refname)
 {
-	return !strcmp(refname, "HEAD") ||
-		starts_with(refname, "refs/worktree/") ||
-		starts_with(refname, "refs/bisect/") ||
-		starts_with(refname, "refs/rewritten/");
+	return starts_with(refname, "refs/worktree/") ||
+	       starts_with(refname, "refs/bisect/") ||
+	       starts_with(refname, "refs/rewritten/");
 }
 
 static int is_pseudoref_syntax(const char *refname)
@@ -771,102 +770,6 @@
 	return timeout_ms;
 }
 
-static int write_pseudoref(const char *pseudoref, const struct object_id *oid,
-			   const struct object_id *old_oid, struct strbuf *err)
-{
-	const char *filename;
-	int fd;
-	struct lock_file lock = LOCK_INIT;
-	struct strbuf buf = STRBUF_INIT;
-	int ret = -1;
-
-	if (!oid)
-		return 0;
-
-	strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
-
-	filename = git_path("%s", pseudoref);
-	fd = hold_lock_file_for_update_timeout(&lock, filename, 0,
-					       get_files_ref_lock_timeout_ms());
-	if (fd < 0) {
-		strbuf_addf(err, _("could not open '%s' for writing: %s"),
-			    filename, strerror(errno));
-		goto done;
-	}
-
-	if (old_oid) {
-		struct object_id actual_old_oid;
-
-		if (read_ref(pseudoref, &actual_old_oid)) {
-			if (!is_null_oid(old_oid)) {
-				strbuf_addf(err, _("could not read ref '%s'"),
-					    pseudoref);
-				rollback_lock_file(&lock);
-				goto done;
-			}
-		} else if (is_null_oid(old_oid)) {
-			strbuf_addf(err, _("ref '%s' already exists"),
-				    pseudoref);
-			rollback_lock_file(&lock);
-			goto done;
-		} else if (!oideq(&actual_old_oid, old_oid)) {
-			strbuf_addf(err, _("unexpected object ID when writing '%s'"),
-				    pseudoref);
-			rollback_lock_file(&lock);
-			goto done;
-		}
-	}
-
-	if (write_in_full(fd, buf.buf, buf.len) < 0) {
-		strbuf_addf(err, _("could not write to '%s'"), filename);
-		rollback_lock_file(&lock);
-		goto done;
-	}
-
-	commit_lock_file(&lock);
-	ret = 0;
-done:
-	strbuf_release(&buf);
-	return ret;
-}
-
-static int delete_pseudoref(const char *pseudoref, const struct object_id *old_oid)
-{
-	const char *filename;
-
-	filename = git_path("%s", pseudoref);
-
-	if (old_oid && !is_null_oid(old_oid)) {
-		struct lock_file lock = LOCK_INIT;
-		int fd;
-		struct object_id actual_old_oid;
-
-		fd = hold_lock_file_for_update_timeout(
-				&lock, filename, 0,
-				get_files_ref_lock_timeout_ms());
-		if (fd < 0) {
-			error_errno(_("could not open '%s' for writing"),
-				    filename);
-			return -1;
-		}
-		if (read_ref(pseudoref, &actual_old_oid))
-			die(_("could not read ref '%s'"), pseudoref);
-		if (!oideq(&actual_old_oid, old_oid)) {
-			error(_("unexpected object ID when deleting '%s'"),
-			      pseudoref);
-			rollback_lock_file(&lock);
-			return -1;
-		}
-
-		unlink(filename);
-		rollback_lock_file(&lock);
-	} else {
-		unlink(filename);
-	}
-
-	return 0;
-}
-
 int refs_delete_ref(struct ref_store *refs, const char *msg,
 		    const char *refname,
 		    const struct object_id *old_oid,
@@ -875,11 +778,6 @@
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
 
-	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
-		assert(refs == get_main_ref_store(the_repository));
-		return delete_pseudoref(refname, old_oid);
-	}
-
 	transaction = ref_store_transaction_begin(refs, &err);
 	if (!transaction ||
 	    ref_transaction_delete(transaction, refname, old_oid,
@@ -1210,18 +1108,13 @@
 	struct strbuf err = STRBUF_INIT;
 	int ret = 0;
 
-	if (ref_type(refname) == REF_TYPE_PSEUDOREF) {
-		assert(refs == get_main_ref_store(the_repository));
-		ret = write_pseudoref(refname, new_oid, old_oid, &err);
-	} else {
-		t = ref_store_transaction_begin(refs, &err);
-		if (!t ||
-		    ref_transaction_update(t, refname, new_oid, old_oid,
-					   flags, msg, &err) ||
-		    ref_transaction_commit(t, &err)) {
-			ret = 1;
-			ref_transaction_free(t);
-		}
+	t = ref_store_transaction_begin(refs, &err);
+	if (!t ||
+	    ref_transaction_update(t, refname, new_oid, old_oid, flags, msg,
+				   &err) ||
+	    ref_transaction_commit(t, &err)) {
+		ret = 1;
+		ref_transaction_free(t);
 	}
 	if (ret) {
 		const char *str = _("update_ref failed for ref '%s': %s");
@@ -1634,11 +1527,37 @@
 	return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
+static int refs_read_special_head(struct ref_store *ref_store,
+				  const char *refname, struct object_id *oid,
+				  struct strbuf *referent, unsigned int *type)
+{
+	struct strbuf full_path = STRBUF_INIT;
+	struct strbuf content = STRBUF_INIT;
+	int result = -1;
+	strbuf_addf(&full_path, "%s/%s", ref_store->gitdir, refname);
+
+	if (strbuf_read_file(&content, full_path.buf, 0) < 0)
+		goto done;
+
+	result = parse_loose_ref_contents(content.buf, oid, referent, type);
+
+done:
+	strbuf_release(&full_path);
+	strbuf_release(&content);
+	return result;
+}
+
 int refs_read_raw_ref(struct ref_store *ref_store,
 		      const char *refname, struct object_id *oid,
 		      struct strbuf *referent, unsigned int *type)
 {
-	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, type);
+	if (!strcmp(refname, "FETCH_HEAD") || !strcmp(refname, "MERGE_HEAD")) {
+		return refs_read_special_head(ref_store, refname, oid, referent,
+					      type);
+	}
+
+	return ref_store->be->read_raw_ref(ref_store, refname, oid, referent,
+					   type);
 }
 
 /* This function needs to return a meaningful errno on failure */
@@ -2031,24 +1950,17 @@
 	return 0;
 }
 
-static const char hook_not_found;
-static const char *hook;
-
 static int run_transaction_hook(struct ref_transaction *transaction,
 				const char *state)
 {
 	struct child_process proc = CHILD_PROCESS_INIT;
 	struct strbuf buf = STRBUF_INIT;
+	const char *hook;
 	int ret = 0, i;
 
-	if (hook == &hook_not_found)
-		return ret;
+	hook = find_hook("reference-transaction");
 	if (!hook)
-		hook = find_hook("reference-transaction");
-	if (!hook) {
-		hook = &hook_not_found;
 		return ret;
-	}
 
 	strvec_pushl(&proc.args, hook, state, NULL);
 	proc.in = -1;
diff --git a/refs.h b/refs.h
index 29e2812..04bd250 100644
--- a/refs.h
+++ b/refs.h
@@ -105,6 +105,8 @@
 				  const struct string_list *skip,
 				  struct strbuf *err);
 
+int refs_ref_exists(struct ref_store *refs, const char *refname);
+
 int ref_exists(const char *refname);
 
 int should_autocreate_reflog(const char *refname);
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 985631f..dd712e4 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -67,7 +67,6 @@
 	struct ref_store base;
 	unsigned int store_flags;
 
-	char *gitdir;
 	char *gitcommondir;
 
 	struct ref_cache *loose;
@@ -94,18 +93,17 @@
 	struct ref_store *ref_store = (struct ref_store *)refs;
 	struct strbuf sb = STRBUF_INIT;
 
+	ref_store->gitdir = xstrdup(gitdir);
 	base_ref_store_init(ref_store, &refs_be_files);
 	refs->store_flags = flags;
 
-	refs->gitdir = xstrdup(gitdir);
 	get_common_dir_noenv(&sb, gitdir);
 	refs->gitcommondir = strbuf_detach(&sb, NULL);
 	strbuf_addf(&sb, "%s/packed-refs", refs->gitcommondir);
 	refs->packed_ref_store = packed_ref_store_create(sb.buf, flags);
 	strbuf_release(&sb);
 
-	chdir_notify_reparent("files-backend $GIT_DIR",
-			      &refs->gitdir);
+	chdir_notify_reparent("files-backend $GIT_DIR", &refs->base.gitdir);
 	chdir_notify_reparent("files-backend $GIT_COMMONDIR",
 			      &refs->gitcommondir);
 
@@ -176,7 +174,7 @@
 	switch (ref_type(refname)) {
 	case REF_TYPE_PER_WORKTREE:
 	case REF_TYPE_PSEUDOREF:
-		strbuf_addf(sb, "%s/logs/%s", refs->gitdir, refname);
+		strbuf_addf(sb, "%s/logs/%s", refs->base.gitdir, refname);
 		break;
 	case REF_TYPE_OTHER_PSEUDOREF:
 	case REF_TYPE_MAIN_PSEUDOREF:
@@ -198,7 +196,7 @@
 	switch (ref_type(refname)) {
 	case REF_TYPE_PER_WORKTREE:
 	case REF_TYPE_PSEUDOREF:
-		strbuf_addf(sb, "%s/%s", refs->gitdir, refname);
+		strbuf_addf(sb, "%s/%s", refs->base.gitdir, refname);
 		break;
 	case REF_TYPE_MAIN_PSEUDOREF:
 		if (!skip_prefix(refname, "main-worktree/", &refname))
@@ -360,7 +358,6 @@
 	struct strbuf sb_path = STRBUF_INIT;
 	const char *path;
 	const char *buf;
-	const char *p;
 	struct stat st;
 	int fd;
 	int ret = -1;
@@ -465,29 +462,8 @@
 	close(fd);
 	strbuf_rtrim(&sb_contents);
 	buf = sb_contents.buf;
-	if (skip_prefix(buf, "ref:", &buf)) {
-		while (isspace(*buf))
-			buf++;
 
-		strbuf_reset(referent);
-		strbuf_addstr(referent, buf);
-		*type |= REF_ISSYMREF;
-		ret = 0;
-		goto out;
-	}
-
-	/*
-	 * Please note that FETCH_HEAD has additional
-	 * data after the sha.
-	 */
-	if (parse_oid_hex(buf, oid, &p) ||
-	    (*p != '\0' && !isspace(*p))) {
-		*type |= REF_ISBROKEN;
-		errno = EINVAL;
-		goto out;
-	}
-
-	ret = 0;
+	ret = parse_loose_ref_contents(buf, oid, referent, type);
 
 out:
 	save_errno = errno;
@@ -497,6 +473,32 @@
 	return ret;
 }
 
+int parse_loose_ref_contents(const char *buf, struct object_id *oid,
+			     struct strbuf *referent, unsigned int *type)
+{
+	const char *p;
+	if (skip_prefix(buf, "ref:", &buf)) {
+		while (isspace(*buf))
+			buf++;
+
+		strbuf_reset(referent);
+		strbuf_addstr(referent, buf);
+		*type |= REF_ISSYMREF;
+		return 0;
+	}
+
+	/*
+	 * FETCH_HEAD has additional data after the sha.
+	 */
+	if (parse_oid_hex(buf, oid, &p) ||
+	    (*p != '\0' && !isspace(*p))) {
+		*type |= REF_ISBROKEN;
+		errno = EINVAL;
+		return -1;
+	}
+	return 0;
+}
+
 static void unlock_ref(struct ref_lock *lock)
 {
 	rollback_lock_file(&lock->lk);
@@ -2199,12 +2201,11 @@
 		files_downcast(ref_store, REF_STORE_READ,
 			       "reflog_iterator_begin");
 
-	if (!strcmp(refs->gitdir, refs->gitcommondir)) {
+	if (!strcmp(refs->base.gitdir, refs->gitcommondir)) {
 		return reflog_iterator_begin(ref_store, refs->gitcommondir);
 	} else {
 		return merge_ref_iterator_begin(
-			0,
-			reflog_iterator_begin(ref_store, refs->gitdir),
+			0, reflog_iterator_begin(ref_store, refs->base.gitdir),
 			reflog_iterator_begin(ref_store, refs->gitcommondir),
 			reflog_iterator_select, refs);
 	}
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 4458a0f..b912f25 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -200,6 +200,7 @@
 	struct ref_store *ref_store = (struct ref_store *)refs;
 
 	base_ref_store_init(ref_store, &refs_be_packed);
+	ref_store->gitdir = xstrdup(path);
 	refs->store_flags = store_flags;
 
 	refs->path = xstrdup(path);
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 357359a..527b0a6 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -667,14 +667,23 @@
 /*
  * A representation of the reference store for the main repository or
  * a submodule. The ref_store instances for submodules are kept in a
- * linked list.
+ * hash map; see get_submodule_ref_store() for more info.
  */
 struct ref_store {
 	/* The backend describing this ref_store's storage scheme: */
 	const struct ref_storage_be *be;
+
+	/* The gitdir that this ref_store applies to: */
+	char *gitdir;
 };
 
 /*
+ * Parse contents of a loose ref file.
+ */
+int parse_loose_ref_contents(const char *buf, struct object_id *oid,
+			     struct strbuf *referent, unsigned int *type);
+
+/*
  * Fill in the generic part of refs and add it to our collection of
  * reference stores.
  */
diff --git a/refspec.h b/refspec.h
index 23e1555..8d654e3 100644
--- a/refspec.h
+++ b/refspec.h
@@ -4,6 +4,19 @@
 #define TAG_REFSPEC "refs/tags/*:refs/tags/*"
 extern const struct refspec_item *tag_refspec;
 
+/**
+ * A struct refspec_item holds the parsed interpretation of a refspec.  If it will
+ * force updates (starts with a '+'), force is true.  If it is a pattern
+ * (sides end with '*') pattern is true.  src and dest are the two sides
+ * (including '*' characters if present); if there is only one side, it is src,
+ * and dst is NULL; if sides exist but are empty (i.e., the refspec either
+ * starts or ends with ':'), the corresponding side is "".
+ *
+ * remote_find_tracking(), given a remote and a struct refspec_item with either src
+ * or dst filled out, will fill out the other such that the result is in the
+ * "fetch" specification for the remote (note that this evaluates patterns and
+ * returns a single result).
+ */
 struct refspec_item {
 	unsigned force : 1;
 	unsigned pattern : 1;
@@ -21,20 +34,8 @@
 #define REFSPEC_INIT_PUSH { .fetch = REFSPEC_PUSH }
 
 /**
- * A struct refspec holds the parsed interpretation of a refspec.  If it will
- * force updates (starts with a '+'), force is true.  If it is a pattern
- * (sides end with '*') pattern is true.  src and dest are the two sides
- * (including '*' characters if present); if there is only one side, it is src,
- * and dst is NULL; if sides exist but are empty (i.e., the refspec either
- * starts or ends with ':'), the corresponding side is "".
- *
- * An array of strings can be parsed into an array of struct refspecs using
+ * An array of strings can be parsed into a struct refspec using
  * parse_fetch_refspec() or parse_push_refspec().
- *
- * remote_find_tracking(), given a remote and a struct refspec with either src
- * or dst filled out, will fill out the other such that the result is in the
- * "fetch" specification for the remote (note that this evaluates patterns and
- * returns a single result).
  */
 struct refspec {
 	struct refspec_item *items;
diff --git a/revision.c b/revision.c
index 3dcf689..08c2ad2 100644
--- a/revision.c
+++ b/revision.c
@@ -1815,7 +1815,7 @@
 
 	revs->repo = r;
 	revs->abbrev = DEFAULT_ABBREV;
-	revs->ignore_merges = 1;
+	revs->ignore_merges = -1;
 	revs->simplify_history = 1;
 	revs->pruning.repo = r;
 	revs->pruning.flags.recursive = 1;
@@ -2017,7 +2017,7 @@
 	return ret;
 }
 
-int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
+static int handle_revision_arg_1(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
 {
 	struct object_context oc;
 	char *mark;
@@ -2092,6 +2092,14 @@
 	return 0;
 }
 
+int handle_revision_arg(const char *arg, struct rev_info *revs, int flags, unsigned revarg_opt)
+{
+	int ret = handle_revision_arg_1(arg, revs, flags, revarg_opt);
+	if (!ret)
+		revs->rev_input_given = 1;
+	return ret;
+}
+
 static void read_pathspec_from_stdin(struct strbuf *sb,
 				     struct strvec *prune)
 {
@@ -2345,6 +2353,15 @@
 		revs->diffopt.flags.tree_in_recursive = 1;
 	} else if (!strcmp(arg, "-m")) {
 		revs->ignore_merges = 0;
+	} else if ((argcount = parse_long_opt("diff-merges", argv, &optarg))) {
+		if (!strcmp(optarg, "off")) {
+			revs->ignore_merges = 1;
+		} else {
+			die(_("unknown value for --diff-merges: %s"), optarg);
+		}
+		return argcount;
+	} else if (!strcmp(arg, "--no-diff-merges")) {
+		revs->ignore_merges = 1;
 	} else if (!strcmp(arg, "-c")) {
 		revs->diff = 1;
 		revs->dense_combined_merges = 0;
@@ -2694,7 +2711,7 @@
  */
 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
 {
-	int i, flags, left, seen_dashdash, got_rev_arg = 0, revarg_opt;
+	int i, flags, left, seen_dashdash, revarg_opt;
 	struct strvec prune_data = STRVEC_INIT;
 	const char *submodule = NULL;
 	int seen_end_of_options = 0;
@@ -2783,8 +2800,6 @@
 			strvec_pushv(&prune_data, argv + i);
 			break;
 		}
-		else
-			got_rev_arg = 1;
 	}
 
 	if (prune_data.nr) {
@@ -2813,7 +2828,7 @@
 		opt->tweak(revs, opt);
 	if (revs->show_merge)
 		prepare_show_merge(revs);
-	if (revs->def && !revs->pending.nr && !revs->rev_input_given && !got_rev_arg) {
+	if (revs->def && !revs->pending.nr && !revs->rev_input_given) {
 		struct object_id oid;
 		struct object *object;
 		struct object_context oc;
@@ -2854,8 +2869,10 @@
 			copy_pathspec(&revs->diffopt.pathspec,
 				      &revs->prune_data);
 	}
-	if (revs->combine_merges)
+	if (revs->combine_merges && revs->ignore_merges < 0)
 		revs->ignore_merges = 0;
+	if (revs->ignore_merges < 0)
+		revs->ignore_merges = 1;
 	if (revs->combined_all_paths && !revs->combine_merges)
 		die("--combined-all-paths makes no sense without -c or --cc");
 
@@ -2889,9 +2906,6 @@
 	if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
 		die("cannot use --grep-reflog without --walk-reflogs");
 
-	if (revs->first_parent_only && revs->bisect)
-		die(_("--first-parent is incompatible with --bisect"));
-
 	if (revs->line_level_traverse &&
 	    (revs->diffopt.output_format & ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT)))
 		die(_("-L does not yet support diff formats besides -p and -s"));
diff --git a/revision.h b/revision.h
index 889216c..c1e5bcf 100644
--- a/revision.h
+++ b/revision.h
@@ -190,11 +190,11 @@
 			show_root_diff:1,
 			no_commit_id:1,
 			verbose_header:1,
-			ignore_merges:1,
 			combine_merges:1,
 			combined_all_paths:1,
 			dense_combined_merges:1,
 			always_show_header:1;
+	int             ignore_merges:2;
 
 	/* Format info */
 	int		show_notes;
diff --git a/sequencer.c b/sequencer.c
index cc3f8fa..e8676e9 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -150,6 +150,8 @@
  * command-line.
  */
 static GIT_PATH_FUNC(rebase_path_gpg_sign_opt, "rebase-merge/gpg_sign_opt")
+static GIT_PATH_FUNC(rebase_path_cdate_is_adate, "rebase-merge/cdate_is_adate")
+static GIT_PATH_FUNC(rebase_path_ignore_date, "rebase-merge/ignore_date")
 static GIT_PATH_FUNC(rebase_path_orig_head, "rebase-merge/orig-head")
 static GIT_PATH_FUNC(rebase_path_verbose, "rebase-merge/verbose")
 static GIT_PATH_FUNC(rebase_path_quiet, "rebase-merge/quiet")
@@ -303,6 +305,8 @@
 		}
 	}
 
+	free(opts->committer_name);
+	free(opts->committer_email);
 	free(opts->gpg_sign);
 	free(opts->strategy);
 	for (i = 0; i < opts->xopts_nr; i++)
@@ -355,7 +359,7 @@
 	subject_len = find_commit_subject(out->message, &subject);
 
 	out->subject = xmemdupz(subject, subject_len);
-	out->label = xstrfmt("%s... %s", abbrev, out->subject);
+	out->label = xstrfmt("%s (%s)", abbrev, out->subject);
 	out->parent_label = xstrfmt("parent of %s", out->label);
 
 	return 0;
@@ -381,7 +385,8 @@
 		 * (typically rebase --interactive) wants to take care
 		 * of the commit itself so remove CHERRY_PICK_HEAD
 		 */
-		unlink(git_path_cherry_pick_head(r));
+		refs_delete_ref(get_main_ref_store(r), "", "CHERRY_PICK_HEAD",
+				NULL, 0);
 		return;
 	}
 
@@ -863,6 +868,22 @@
 	return NULL;
 }
 
+static const char *author_date_from_env_array(const struct strvec *env)
+{
+	int i;
+	const char *date;
+
+	for (i = 0; i < env->nr; i++)
+		if (skip_prefix(env->v[i],
+				"GIT_AUTHOR_DATE=", &date))
+			return date;
+	/*
+	 * If GIT_AUTHOR_DATE is missing we should have already errored out when
+	 * reading the script
+	 */
+	BUG("GIT_AUTHOR_DATE missing from author script");
+}
+
 static const char staged_changes_advice[] =
 N_("you have staged changes in your working tree\n"
 "If these changes are meant to be squashed into the previous commit, run:\n"
@@ -929,6 +950,14 @@
 			     gpg_opt, gpg_opt);
 	}
 
+	if (opts->committer_date_is_author_date)
+		strvec_pushf(&cmd.env_array, "GIT_COMMITTER_DATE=%s",
+			     opts->ignore_date ?
+			     "" :
+			     author_date_from_env_array(&cmd.env_array));
+	if (opts->ignore_date)
+		strvec_push(&cmd.env_array, "GIT_AUTHOR_DATE=");
+
 	strvec_push(&cmd.args, "commit");
 
 	if (!(flags & VERIFY_MSG))
@@ -1308,6 +1337,7 @@
 	struct strbuf err = STRBUF_INIT;
 	struct strbuf commit_msg = STRBUF_INIT;
 	char *amend_author = NULL;
+	const char *committer = NULL;
 	const char *hook_commit = NULL;
 	enum commit_msg_cleanup_mode cleanup;
 	int res = 0;
@@ -1399,10 +1429,57 @@
 		goto out;
 	}
 
-	reset_ident_date();
+	if (opts->committer_date_is_author_date) {
+		struct ident_split id;
+		struct strbuf date = STRBUF_INIT;
 
-	if (commit_tree_extended(msg->buf, msg->len, &tree, parents,
-				 oid, author, opts->gpg_sign, extra)) {
+		if (!opts->ignore_date) {
+			if (split_ident_line(&id, author, (int)strlen(author)) < 0) {
+				res = error(_("invalid author identity '%s'"),
+					    author);
+				goto out;
+			}
+			if (!id.date_begin) {
+				res = error(_(
+					"corrupt author: missing date information"));
+				goto out;
+			}
+			strbuf_addf(&date, "@%.*s %.*s",
+				    (int)(id.date_end - id.date_begin),
+				    id.date_begin,
+				    (int)(id.tz_end - id.tz_begin),
+				    id.tz_begin);
+		} else {
+			reset_ident_date();
+		}
+		committer = fmt_ident(opts->committer_name,
+				      opts->committer_email,
+				      WANT_COMMITTER_IDENT,
+				      opts->ignore_date ? NULL : date.buf,
+				      IDENT_STRICT);
+		strbuf_release(&date);
+	} else {
+		reset_ident_date();
+	}
+
+	if (opts->ignore_date) {
+		struct ident_split id;
+		char *name, *email;
+
+		if (split_ident_line(&id, author, strlen(author)) < 0) {
+			error(_("invalid author identity '%s'"), author);
+			goto out;
+		}
+		name = xmemdupz(id.name_begin, id.name_end - id.name_begin);
+		email = xmemdupz(id.mail_begin, id.mail_end - id.mail_begin);
+		author = fmt_ident(name, email, WANT_AUTHOR_IDENT, NULL,
+				   IDENT_STRICT);
+		free(name);
+		free(email);
+	}
+
+	if (commit_tree_extended(msg->buf, msg->len, &tree, parents, oid,
+				 author, committer, opts->gpg_sign, extra)) {
 		res = error(_("failed to write commit object"));
 		goto out;
 	}
@@ -1455,7 +1532,8 @@
 				    author, opts, flags, &oid);
 		strbuf_release(&sb);
 		if (!res) {
-			unlink(git_path_cherry_pick_head(r));
+			refs_delete_ref(get_main_ref_store(r), "",
+					"CHERRY_PICK_HEAD", NULL, 0);
 			unlink(git_path_merge_msg(r));
 			if (!is_rebase_i(opts))
 				print_commit_summary(r, NULL, &oid,
@@ -1966,7 +2044,8 @@
 		flags |= ALLOW_EMPTY;
 	} else if (allow == 2) {
 		drop_commit = 1;
-		unlink(git_path_cherry_pick_head(r));
+		refs_delete_ref(get_main_ref_store(r), "", "CHERRY_PICK_HEAD",
+				NULL, 0);
 		unlink(git_path_merge_msg(r));
 		fprintf(stderr,
 			_("dropping %s %s -- patch contents already upstream\n"),
@@ -2305,15 +2384,19 @@
 	struct replay_opts opts = REPLAY_OPTS_INIT;
 	int need_cleanup = 0;
 
-	if (file_exists(git_path_cherry_pick_head(r))) {
-		if (!unlink(git_path_cherry_pick_head(r)) && verbose)
+	if (refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD")) {
+		if (!refs_delete_ref(get_main_ref_store(r), "",
+				     "CHERRY_PICK_HEAD", NULL, 0) &&
+		    verbose)
 			warning(_("cancelling a cherry picking in progress"));
 		opts.action = REPLAY_PICK;
 		need_cleanup = 1;
 	}
 
-	if (file_exists(git_path_revert_head(r))) {
-		if (!unlink(git_path_revert_head(r)) && verbose)
+	if (refs_ref_exists(get_main_ref_store(r), "REVERT_HEAD")) {
+		if (!refs_delete_ref(get_main_ref_store(r), "", "REVERT_HEAD",
+				     NULL, 0) &&
+		    verbose)
 			warning(_("cancelling a revert in progress"));
 		opts.action = REPLAY_REVERT;
 		need_cleanup = 1;
@@ -2528,6 +2611,16 @@
 			opts->signoff = 1;
 		}
 
+		if (file_exists(rebase_path_cdate_is_adate())) {
+			opts->allow_ff = 0;
+			opts->committer_date_is_author_date = 1;
+		}
+
+		if (file_exists(rebase_path_ignore_date())) {
+			opts->allow_ff = 0;
+			opts->ignore_date = 1;
+		}
+
 		if (file_exists(rebase_path_reschedule_failed_exec()))
 			opts->reschedule_failed_exec = 1;
 
@@ -2623,6 +2716,10 @@
 		write_file(rebase_path_drop_redundant_commits(), "%s", "");
 	if (opts->keep_redundant_commits)
 		write_file(rebase_path_keep_redundant_commits(), "%s", "");
+	if (opts->committer_date_is_author_date)
+		write_file(rebase_path_cdate_is_adate(), "%s", "");
+	if (opts->ignore_date)
+		write_file(rebase_path_ignore_date(), "%s", "");
 	if (opts->reschedule_failed_exec)
 		write_file(rebase_path_reschedule_failed_exec(), "%s", "");
 
@@ -2671,8 +2768,9 @@
 	enum replay_action action;
 	const char *in_progress_error = NULL;
 	const char *in_progress_advice = NULL;
-	unsigned int advise_skip = file_exists(git_path_revert_head(r)) ||
-				file_exists(git_path_cherry_pick_head(r));
+	unsigned int advise_skip =
+		refs_ref_exists(get_main_ref_store(r), "REVERT_HEAD") ||
+		refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD");
 
 	if (!sequencer_get_last_command(r, &action)) {
 		switch (action) {
@@ -2771,8 +2869,8 @@
 {
 	struct object_id head_oid;
 
-	if (!file_exists(git_path_cherry_pick_head(r)) &&
-	    !file_exists(git_path_revert_head(r)))
+	if (!refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD") &&
+	    !refs_ref_exists(get_main_ref_store(r), "REVERT_HEAD"))
 		return error(_("no cherry-pick or revert in progress"));
 	if (read_ref_full("HEAD", 0, &head_oid, NULL))
 		return error(_("cannot resolve HEAD"));
@@ -2866,7 +2964,7 @@
 	 */
 	switch (opts->action) {
 	case REPLAY_REVERT:
-		if (!file_exists(git_path_revert_head(r))) {
+		if (!refs_ref_exists(get_main_ref_store(r), "REVERT_HEAD")) {
 			if (action != REPLAY_REVERT)
 				return error(_("no revert in progress"));
 			if (!rollback_is_safe())
@@ -2874,7 +2972,8 @@
 		}
 		break;
 	case REPLAY_PICK:
-		if (!file_exists(git_path_cherry_pick_head(r))) {
+		if (!refs_ref_exists(get_main_ref_store(r),
+				     "CHERRY_PICK_HEAD")) {
 			if (action != REPLAY_PICK)
 				return error(_("no cherry-pick in progress"));
 			if (!rollback_is_safe())
@@ -3543,6 +3642,14 @@
 			goto leave_merge;
 		}
 
+		if (opts->committer_date_is_author_date)
+			strvec_pushf(&cmd.env_array, "GIT_COMMITTER_DATE=%s",
+				     opts->ignore_date ?
+				     "" :
+				     author_date_from_env_array(&cmd.env_array));
+		if (opts->ignore_date)
+			strvec_push(&cmd.env_array, "GIT_AUTHOR_DATE=");
+
 		cmd.git_cmd = 1;
 		strvec_push(&cmd.args, "merge");
 		strvec_push(&cmd.args, "-s");
@@ -3569,7 +3676,8 @@
 				    oid_to_hex(&j->item->object.oid));
 
 		strbuf_release(&ref_name);
-		unlink(git_path_cherry_pick_head(r));
+		refs_delete_ref(get_main_ref_store(r), "", "CHERRY_PICK_HEAD",
+				NULL, 0);
 		rollback_lock_file(&lock);
 
 		rollback_lock_file(&lock);
@@ -3906,7 +4014,9 @@
 	prev_reflog_action = xstrdup(getenv(GIT_REFLOG_ACTION));
 	if (opts->allow_ff)
 		assert(!(opts->signoff || opts->no_commit ||
-				opts->record_origin || opts->edit));
+			 opts->record_origin || opts->edit ||
+			 opts->committer_date_is_author_date ||
+			 opts->ignore_date));
 	if (read_and_refresh_cache(r, opts))
 		return -1;
 
@@ -4201,8 +4311,8 @@
 {
 	const char *argv[] = { "commit", NULL };
 
-	if (!file_exists(git_path_cherry_pick_head(r)) &&
-	    !file_exists(git_path_revert_head(r)))
+	if (!refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD") &&
+	    !refs_ref_exists(get_main_ref_store(r), "REVERT_HEAD"))
 		return error(_("no cherry-pick or revert in progress"));
 	return run_command_v_opt(argv, RUN_GIT_CMD);
 }
@@ -4318,9 +4428,10 @@
 	}
 
 	if (is_clean) {
-		const char *cherry_pick_head = git_path_cherry_pick_head(r);
-
-		if (file_exists(cherry_pick_head) && unlink(cherry_pick_head))
+		if (refs_ref_exists(get_main_ref_store(r),
+				    "CHERRY_PICK_HEAD") &&
+		    refs_delete_ref(get_main_ref_store(r), "",
+				    "CHERRY_PICK_HEAD", NULL, 0))
 			return error(_("could not remove CHERRY_PICK_HEAD"));
 		if (!final_fixup)
 			return 0;
@@ -4347,6 +4458,22 @@
 	return 0;
 }
 
+static int init_committer(struct replay_opts *opts)
+{
+	struct ident_split id;
+	const char *committer;
+
+	committer = git_committer_info(IDENT_STRICT);
+	if (split_ident_line(&id, committer, strlen(committer)) < 0)
+		return error(_("invalid committer '%s'"), committer);
+	opts->committer_name =
+		xmemdupz(id.name_begin, id.name_end - id.name_begin);
+	opts->committer_email =
+		xmemdupz(id.mail_begin, id.mail_end - id.mail_end);
+
+	return 0;
+}
+
 int sequencer_continue(struct repository *r, struct replay_opts *opts)
 {
 	struct todo_list todo_list = TODO_LIST_INIT;
@@ -4358,6 +4485,9 @@
 	if (read_populate_opts(opts))
 		return -1;
 	if (is_rebase_i(opts)) {
+		if (opts->committer_date_is_author_date && init_committer(opts))
+			return -1;
+
 		if ((res = read_populate_todo(r, &todo_list, opts)))
 			goto release_todo_list;
 
@@ -4379,8 +4509,9 @@
 
 	if (!is_rebase_i(opts)) {
 		/* Verify that the conflict has been resolved */
-		if (file_exists(git_path_cherry_pick_head(r)) ||
-		    file_exists(git_path_revert_head(r))) {
+		if (refs_ref_exists(get_main_ref_store(r),
+				    "CHERRY_PICK_HEAD") ||
+		    refs_ref_exists(get_main_ref_store(r), "REVERT_HEAD")) {
 			res = continue_single_pick(r);
 			if (res)
 				goto release_todo_list;
@@ -5178,13 +5309,14 @@
 		    struct string_list *commands, unsigned autosquash,
 		    struct todo_list *todo_list)
 {
-	const char *shortonto, *todo_file = rebase_path_todo();
+	char shortonto[GIT_MAX_HEXSZ + 1];
+	const char *todo_file = rebase_path_todo();
 	struct todo_list new_todo = TODO_LIST_INIT;
 	struct strbuf *buf = &todo_list->buf, buf2 = STRBUF_INIT;
 	struct object_id oid = onto->object.oid;
 	int res;
 
-	shortonto = find_unique_abbrev(&oid, DEFAULT_ABBREV);
+	find_unique_abbrev_r(shortonto, &oid, DEFAULT_ABBREV);
 
 	if (buf->len == 0) {
 		struct todo_item *item = append_new_todo(todo_list);
@@ -5250,6 +5382,9 @@
 
 	res = -1;
 
+	if (opts->committer_date_is_author_date && init_committer(opts))
+		goto cleanup;
+
 	if (checkout_onto(r, opts, onto_name, &oid, orig_head))
 		goto cleanup;
 
@@ -5442,7 +5577,7 @@
 
 int sequencer_determine_whence(struct repository *r, enum commit_whence *whence)
 {
-	if (file_exists(git_path_cherry_pick_head(r))) {
+	if (refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD")) {
 		struct object_id cherry_pick_head, rebase_head;
 
 		if (file_exists(git_path_seq_dir()))
diff --git a/sequencer.h b/sequencer.h
index d31c41f..b2a501e 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -45,9 +45,13 @@
 	int verbose;
 	int quiet;
 	int reschedule_failed_exec;
+	int committer_date_is_author_date;
+	int ignore_date;
 
 	int mainline;
 
+	char *committer_name;
+	char *committer_email;
 	char *gpg_sign;
 	enum commit_msg_cleanup_mode default_msg_cleanup;
 	int explicit_cleanup;
diff --git a/sideband.c b/sideband.c
index ef85111..0a60662 100644
--- a/sideband.c
+++ b/sideband.c
@@ -147,7 +147,7 @@
 	switch (band) {
 	case 3:
 		if (die_on_error)
-			die("remote error: %s", buf + 1);
+			die(_("remote error: %s"), buf + 1);
 		strbuf_addf(scratch, "%s%s", scratch->len ? "\n" : "",
 			    DISPLAY_PREFIX);
 		maybe_colorize_sideband(scratch, buf + 1, len);
diff --git a/split-index.c b/split-index.c
index e6154e4..c0e8ad6 100644
--- a/split-index.c
+++ b/split-index.c
@@ -79,8 +79,10 @@
 	if (si->base &&
 		si->base->ce_mem_pool) {
 
-		if (!istate->ce_mem_pool)
-			mem_pool_init(&istate->ce_mem_pool, 0);
+		if (!istate->ce_mem_pool) {
+			istate->ce_mem_pool = xmalloc(sizeof(struct mem_pool));
+			mem_pool_init(istate->ce_mem_pool, 0);
+		}
 
 		mem_pool_combine(istate->ce_mem_pool, istate->split_index->base->ce_mem_pool);
 	}
diff --git a/submodule.c b/submodule.c
index a52b93a..d0b70ca 100644
--- a/submodule.c
+++ b/submodule.c
@@ -194,7 +194,7 @@
 		char *key;
 
 		key = xstrfmt("submodule.%s.ignore", submodule->name);
-		if (repo_config_get_string_const(the_repository, key, &ignore))
+		if (repo_config_get_string_tmp(the_repository, key, &ignore))
 			ignore = submodule->ignore;
 		free(key);
 
@@ -1299,7 +1299,7 @@
 
 		int fetch_recurse = submodule->fetch_recurse;
 		key = xstrfmt("submodule.%s.fetchRecurseSubmodules", submodule->name);
-		if (!repo_config_get_string_const(spf->r, key, &value)) {
+		if (!repo_config_get_string_tmp(spf->r, key, &value)) {
 			fetch_recurse = parse_fetch_recurse_submodules_arg(key, value);
 		}
 		free(key);
diff --git a/t/README b/t/README
index 70ec61c..2adaf7c 100644
--- a/t/README
+++ b/t/README
@@ -421,6 +421,10 @@
 the default when running tests), errors out when an abbreviated option
 is used.
 
+GIT_TEST_DEFAULT_HASH=<hash-algo> specifies which hash algorithm to
+use in the test scripts. Recognized values for <hash-algo> are "sha1"
+and "sha256".
+
 Naming Tests
 ------------
 
diff --git a/t/helper/test-config.c b/t/helper/test-config.c
index 234c722..a6e9367 100644
--- a/t/helper/test-config.c
+++ b/t/helper/test-config.c
@@ -126,7 +126,7 @@
 			goto exit1;
 		}
 	} else if (argc == 3 && !strcmp(argv[1], "get_string")) {
-		if (!git_config_get_string_const(argv[2], &v)) {
+		if (!git_config_get_string_tmp(argv[2], &v)) {
 			printf("%s\n", v);
 			goto exit0;
 		} else {
diff --git a/t/helper/test-read-midx.c b/t/helper/test-read-midx.c
index 831b586..2430880 100644
--- a/t/helper/test-read-midx.c
+++ b/t/helper/test-read-midx.c
@@ -7,14 +7,18 @@
 static int read_midx_file(const char *object_dir)
 {
 	uint32_t i;
-	struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
+	struct multi_pack_index *m;
+
+	setup_git_directory();
+	m = load_multi_pack_index(object_dir, 1);
 
 	if (!m)
 		return 1;
 
-	printf("header: %08x %d %d %d\n",
+	printf("header: %08x %d %d %d %d\n",
 	       m->signature,
 	       m->version,
+	       m->hash_len,
 	       m->num_chunks,
 	       m->num_packs);
 
diff --git a/t/perf/README b/t/perf/README
index c7b70e2..bd649af 100644
--- a/t/perf/README
+++ b/t/perf/README
@@ -84,6 +84,15 @@
 	probably be about linux.git size for optimal results.
 	Both default to the git.git you are running from.
 
+    GIT_PERF_EXTRA
+	Boolean to enable additional tests. Most test scripts are
+	written to detect regressions between two versions of Git, and
+	the output will compare timings for individual tests between
+	those versions. Some scripts have additional tests which are not
+	run by default, that show patterns within a single version of
+	Git (e.g., performance of index-pack as the number of threads
+	changes). These can be enabled with GIT_PERF_EXTRA.
+
 You can also pass the options taken by ordinary git tests; the most
 useful one is:
 
diff --git a/t/perf/p1400-update-ref.sh b/t/perf/p1400-update-ref.sh
index d275a81..ce5ac3e 100755
--- a/t/perf/p1400-update-ref.sh
+++ b/t/perf/p1400-update-ref.sh
@@ -7,11 +7,13 @@
 test_perf_fresh_repo
 
 test_expect_success "setup" '
+	git init --bare target-repo.git &&
 	test_commit PRE &&
 	test_commit POST &&
 	printf "create refs/heads/%d PRE\n" $(test_seq 1000) >create &&
 	printf "update refs/heads/%d POST PRE\n" $(test_seq 1000) >update &&
-	printf "delete refs/heads/%d POST\n" $(test_seq 1000) >delete
+	printf "delete refs/heads/%d POST\n" $(test_seq 1000) >delete &&
+	git update-ref --stdin <create
 '
 
 test_perf "update-ref" '
@@ -24,9 +26,14 @@
 '
 
 test_perf "update-ref --stdin" '
-	git update-ref --stdin <create &&
 	git update-ref --stdin <update &&
-	git update-ref --stdin <delete
+	git update-ref --stdin <delete &&
+	git update-ref --stdin <create
+'
+
+test_perf "nonatomic push" '
+	git push ./target-repo.git $(test_seq 1000) &&
+	git push --delete ./target-repo.git $(test_seq 1000)
 '
 
 test_done
diff --git a/t/perf/p5302-pack-index.sh b/t/perf/p5302-pack-index.sh
index a9b3e11..228593d 100755
--- a/t/perf/p5302-pack-index.sh
+++ b/t/perf/p5302-pack-index.sh
@@ -13,35 +13,36 @@
 	export PACK
 '
 
-test_perf 'index-pack 0 threads' '
+# Rather than counting up and doubling each time, count down from the endpoint,
+# halving each time. That ensures that our final test uses as many threads as
+# CPUs, even if it isn't a power of 2.
+test_expect_success 'set up thread-counting tests' '
+	t=$(test-tool online-cpus) &&
+	threads= &&
+	while test $t -gt 0
+	do
+		threads="$t $threads"
+		t=$((t / 2))
+	done
+'
+
+test_perf PERF_EXTRA 'index-pack 0 threads' '
 	rm -rf repo.git &&
 	git init --bare repo.git &&
 	GIT_DIR=repo.git git index-pack --threads=1 --stdin < $PACK
 '
 
-test_perf 'index-pack 1 thread ' '
-	rm -rf repo.git &&
-	git init --bare repo.git &&
-	GIT_DIR=repo.git GIT_FORCE_THREADS=1 git index-pack --threads=1 --stdin < $PACK
-'
-
-test_perf 'index-pack 2 threads' '
-	rm -rf repo.git &&
-	git init --bare repo.git &&
-	GIT_DIR=repo.git git index-pack --threads=2 --stdin < $PACK
-'
-
-test_perf 'index-pack 4 threads' '
-	rm -rf repo.git &&
-	git init --bare repo.git &&
-	GIT_DIR=repo.git git index-pack --threads=4 --stdin < $PACK
-'
-
-test_perf 'index-pack 8 threads' '
-	rm -rf repo.git &&
-	git init --bare repo.git &&
-	GIT_DIR=repo.git git index-pack --threads=8 --stdin < $PACK
-'
+for t in $threads
+do
+	THREADS=$t
+	export THREADS
+	test_perf PERF_EXTRA "index-pack $t threads" '
+		rm -rf repo.git &&
+		git init --bare repo.git &&
+		GIT_DIR=repo.git GIT_FORCE_THREADS=1 \
+		git index-pack --threads=$THREADS --stdin <$PACK
+	'
+done
 
 test_perf 'index-pack default number of threads' '
 	rm -rf repo.git &&
diff --git a/t/perf/perf-lib.sh b/t/perf/perf-lib.sh
index 13e3893..821581a 100644
--- a/t/perf/perf-lib.sh
+++ b/t/perf/perf-lib.sh
@@ -245,3 +245,5 @@
 test_export () {
 	export "$@"
 }
+
+test_lazy_prereq PERF_EXTRA 'test_bool_env GIT_PERF_EXTRA false'
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index d71d4c7..50222a1 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -316,6 +316,19 @@
 	test_path_is_dir realgitdir/refs
 '
 
+test_expect_success 'explicit bare & --separate-git-dir incompatible' '
+	test_must_fail git init --bare --separate-git-dir goop.git bare.git 2>err &&
+	test_i18ngrep "mutually exclusive" err
+'
+
+test_expect_success 'implicit bare & --separate-git-dir incompatible' '
+	test_when_finished "rm -rf bare.git" &&
+	mkdir -p bare.git &&
+	test_must_fail env GIT_DIR=. \
+		git -C bare.git init --separate-git-dir goop.git 2>err &&
+	test_i18ngrep "incompatible" err
+'
+
 test_lazy_prereq GETCWD_IGNORES_PERMS '
 	base=GETCWD_TEST_BASE_DIR &&
 	mkdir -p $base/dir &&
diff --git a/t/t0040-parse-options.sh b/t/t0040-parse-options.sh
index f8178ee..14cafc1 100755
--- a/t/t0040-parse-options.sh
+++ b/t/t0040-parse-options.sh
@@ -44,7 +44,7 @@
     --no-ambiguous        negative ambiguity
 
 Standard options
-    --abbrev[=<n>]        use <n> digits to display SHA-1s
+    --abbrev[=<n>]        use <n> digits to display object names
     -v, --verbose         be verbose
     -n, --dry-run         dry run
     -q, --quiet           be quiet
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index d0d3675..770e7be 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -160,10 +160,10 @@
 	git reflog exists $outside
 '
 
-test_expect_success 'core.logAllRefUpdates=always creates no reflog for ORIG_HEAD' '
+test_expect_success 'core.logAllRefUpdates=always creates reflog for ORIG_HEAD' '
 	test_config core.logAllRefUpdates always &&
 	git update-ref ORIG_HEAD $A &&
-	test_must_fail git reflog exists ORIG_HEAD
+	git reflog exists ORIG_HEAD
 '
 
 test_expect_success '--no-create-reflog overrides core.logAllRefUpdates=always' '
@@ -475,57 +475,57 @@
 
 test_expect_success 'given old value for missing pseudoref, do not create' '
 	test_must_fail git update-ref PSEUDOREF $A $B 2>err &&
-	test_path_is_missing .git/PSEUDOREF &&
-	test_i18ngrep "could not read ref" err
+	test_must_fail git rev-parse PSEUDOREF &&
+	test_i18ngrep "unable to resolve reference" err
 '
 
 test_expect_success 'create pseudoref' '
 	git update-ref PSEUDOREF $A &&
-	test $A = $(cat .git/PSEUDOREF)
+	test $A = $(git rev-parse PSEUDOREF)
 '
 
 test_expect_success 'overwrite pseudoref with no old value given' '
 	git update-ref PSEUDOREF $B &&
-	test $B = $(cat .git/PSEUDOREF)
+	test $B = $(git rev-parse PSEUDOREF)
 '
 
 test_expect_success 'overwrite pseudoref with correct old value' '
 	git update-ref PSEUDOREF $C $B &&
-	test $C = $(cat .git/PSEUDOREF)
+	test $C = $(git rev-parse PSEUDOREF)
 '
 
 test_expect_success 'do not overwrite pseudoref with wrong old value' '
 	test_must_fail git update-ref PSEUDOREF $D $E 2>err &&
-	test $C = $(cat .git/PSEUDOREF) &&
-	test_i18ngrep "unexpected object ID" err
+	test $C = $(git rev-parse PSEUDOREF) &&
+	test_i18ngrep "cannot lock ref.*expected" err
 '
 
 test_expect_success 'delete pseudoref' '
 	git update-ref -d PSEUDOREF &&
-	test_path_is_missing .git/PSEUDOREF
+	test_must_fail git rev-parse PSEUDOREF
 '
 
 test_expect_success 'do not delete pseudoref with wrong old value' '
 	git update-ref PSEUDOREF $A &&
 	test_must_fail git update-ref -d PSEUDOREF $B 2>err &&
-	test $A = $(cat .git/PSEUDOREF) &&
-	test_i18ngrep "unexpected object ID" err
+	test $A = $(git rev-parse PSEUDOREF) &&
+	test_i18ngrep "cannot lock ref.*expected" err
 '
 
 test_expect_success 'delete pseudoref with correct old value' '
 	git update-ref -d PSEUDOREF $A &&
-	test_path_is_missing .git/PSEUDOREF
+	test_must_fail git rev-parse PSEUDOREF
 '
 
 test_expect_success 'create pseudoref with old OID zero' '
 	git update-ref PSEUDOREF $A $Z &&
-	test $A = $(cat .git/PSEUDOREF)
+	test $A = $(git rev-parse PSEUDOREF)
 '
 
 test_expect_success 'do not overwrite pseudoref with old OID zero' '
 	test_when_finished git update-ref -d PSEUDOREF &&
 	test_must_fail git update-ref PSEUDOREF $B $Z 2>err &&
-	test $A = $(cat .git/PSEUDOREF) &&
+	test $A = $(git rev-parse PSEUDOREF) &&
 	test_i18ngrep "already exists" err
 '
 
diff --git a/t/t1405-main-ref-store.sh b/t/t1405-main-ref-store.sh
index 331899d..74af927 100755
--- a/t/t1405-main-ref-store.sh
+++ b/t/t1405-main-ref-store.sh
@@ -31,7 +31,10 @@
 test_expect_success 'delete_refs(FOO, refs/tags/new-tag)' '
 	git rev-parse FOO -- &&
 	git rev-parse refs/tags/new-tag -- &&
-	$RUN delete-refs 0 nothing FOO refs/tags/new-tag &&
+	m=$(git rev-parse master) &&
+	REF_NO_DEREF=1 &&
+	$RUN delete-refs $REF_NO_DEREF nothing FOO refs/tags/new-tag &&
+	test_must_fail git rev-parse --symbolic-full-name FOO &&
 	test_must_fail git rev-parse FOO -- &&
 	test_must_fail git rev-parse refs/tags/new-tag --
 '
diff --git a/t/t1416-ref-transaction-hooks.sh b/t/t1416-ref-transaction-hooks.sh
index da58d86..f6e741c 100755
--- a/t/t1416-ref-transaction-hooks.sh
+++ b/t/t1416-ref-transaction-hooks.sh
@@ -7,6 +7,7 @@
 test_expect_success setup '
 	mkdir -p .git/hooks &&
 	test_commit PRE &&
+	PRE_OID=$(git rev-parse PRE) &&
 	test_commit POST &&
 	POST_OID=$(git rev-parse POST)
 '
@@ -106,4 +107,30 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'interleaving hook calls succeed' '
+	test_when_finished "rm -r target-repo.git" &&
+
+	git init --bare target-repo.git &&
+
+	write_script target-repo.git/hooks/reference-transaction <<-\EOF &&
+		echo $0 "$@" >>actual
+	EOF
+
+	write_script target-repo.git/hooks/update <<-\EOF &&
+		echo $0 "$@" >>actual
+	EOF
+
+	cat >expect <<-EOF &&
+		hooks/update refs/tags/PRE $ZERO_OID $PRE_OID
+		hooks/reference-transaction prepared
+		hooks/reference-transaction committed
+		hooks/update refs/tags/POST $ZERO_OID $POST_OID
+		hooks/reference-transaction prepared
+		hooks/reference-transaction committed
+	EOF
+
+	git push ./target-repo.git PRE POST &&
+	test_cmp expect target-repo.git/actual
+'
+
 test_done
diff --git a/t/t2025-checkout-no-overlay.sh b/t/t2025-checkout-no-overlay.sh
index 76330cb..fa9e098 100755
--- a/t/t2025-checkout-no-overlay.sh
+++ b/t/t2025-checkout-no-overlay.sh
@@ -44,4 +44,16 @@
 	test_path_is_missing file1
 '
 
+test_expect_success 'wildcard pathspec matches file in subdirectory' '
+	git reset --hard &&
+	mkdir subdir &&
+	test_commit file3-1 subdir/file3 &&
+	test_commit file3-2 subdir/file3 &&
+
+	git checkout --no-overlay file3-1 "*file3" &&
+	echo file3-1 >expect &&
+	test_path_is_file subdir/file3 &&
+	test_cmp expect subdir/file3
+'
+
 test_done
diff --git a/t/t2072-restore-pathspec-file.sh b/t/t2072-restore-pathspec-file.sh
index 0d47946..b48345b 100755
--- a/t/t2072-restore-pathspec-file.sh
+++ b/t/t2072-restore-pathspec-file.sh
@@ -9,18 +9,21 @@
 test_expect_success setup '
 	test_commit file0 &&
 
+	mkdir dir1 &&
+	echo 1 >dir1/file &&
 	echo 1 >fileA.t &&
 	echo 1 >fileB.t &&
 	echo 1 >fileC.t &&
 	echo 1 >fileD.t &&
-	git add fileA.t fileB.t fileC.t fileD.t &&
+	git add dir1 fileA.t fileB.t fileC.t fileD.t &&
 	git commit -m "files 1" &&
 
+	echo 2 >dir1/file &&
 	echo 2 >fileA.t &&
 	echo 2 >fileB.t &&
 	echo 2 >fileC.t &&
 	echo 2 >fileD.t &&
-	git add fileA.t fileB.t fileC.t fileD.t &&
+	git add dir1 fileA.t fileB.t fileC.t fileD.t &&
 	git commit -m "files 2" &&
 
 	git tag checkpoint
@@ -31,7 +34,7 @@
 }
 
 verify_expect () {
-	git status --porcelain --untracked-files=no -- fileA.t fileB.t fileC.t fileD.t >actual &&
+	git status --porcelain --untracked-files=no -- dir1 fileA.t fileB.t fileC.t fileD.t >actual &&
 	test_cmp expect actual
 }
 
@@ -161,4 +164,14 @@
 	test_i18ngrep -e "you must specify path(s) to restore" err
 '
 
+test_expect_success 'wildcard pathspec matches file in subdirectory' '
+	restore_checkpoint &&
+
+	echo "*file" | git restore --pathspec-from-file=- --source=HEAD^1 &&
+	cat >expect <<-\EOF &&
+	 M dir1/file
+	EOF
+	verify_expect
+'
+
 test_done
diff --git a/t/t3000-ls-files-others.sh b/t/t3000-ls-files-others.sh
index ffdfb16..740ce56 100755
--- a/t/t3000-ls-files-others.sh
+++ b/t/t3000-ls-files-others.sh
@@ -152,7 +152,7 @@
 	)
 '
 
-test_expect_success 'ls-files --o --directory with glob filetype match' '
+test_expect_success 'ls-files -o --directory with glob filetype match' '
 	(
 		cd nested &&
 
@@ -168,7 +168,7 @@
 	)
 '
 
-test_expect_success 'ls-files --o --directory with mix of tracked states' '
+test_expect_success 'ls-files -o --directory with mix of tracked states' '
 	(
 		cd nested &&
 
@@ -184,7 +184,7 @@
 	)
 '
 
-test_expect_success 'ls-files --o --directory with glob filetype match only' '
+test_expect_success 'ls-files -o --directory with glob filetype match only' '
 	(
 		cd nested &&
 
@@ -198,7 +198,7 @@
 	)
 '
 
-test_expect_success 'ls-files --o --directory to get immediate paths under one dir only' '
+test_expect_success 'ls-files -o --directory to get immediate paths under one dir only' '
 	(
 		cd nested &&
 
@@ -212,4 +212,20 @@
 	)
 '
 
+test_expect_success 'ls-files -o avoids listing untracked non-matching gitdir' '
+	test_when_finished "rm -rf nested/untracked/deep/empty" &&
+	(
+		cd nested &&
+
+		git init untracked/deep/empty &&
+		git ls-files --others "untracked/*.c" >actual &&
+
+		cat <<-EOF >expect &&
+		untracked/deep/foo.c
+		EOF
+
+		test_cmp expect actual
+	)
+'
+
 test_done
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 9744e88..07a1617 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -256,7 +256,7 @@
 	D
 	=======
 	G
-	>>>>>>> $commit... G
+	>>>>>>> $commit (G)
 	EOF
 	git tag new-branch1 &&
 	test_must_fail git rebase -i master &&
@@ -1791,6 +1791,12 @@
 	test_i18ngrep "middle of a rebase -- cannot amend." err
 '
 
+test_expect_success 'todo has correct onto hash' '
+	GIT_SEQUENCE_EDITOR=cat git rebase -i no-conflict-branch~4 no-conflict-branch >actual &&
+	onto=$(git rev-parse --short HEAD~4) &&
+	test_i18ngrep "^# Rebase ..* onto $onto" actual
+'
+
 # This must be the last test in this file
 test_expect_success '$EDITOR and friends are unchanged' '
 	test_editor_unchanged
diff --git a/t/t3422-rebase-incompatible-options.sh b/t/t3422-rebase-incompatible-options.sh
index 50e7960..c823406 100755
--- a/t/t3422-rebase-incompatible-options.sh
+++ b/t/t3422-rebase-incompatible-options.sh
@@ -61,8 +61,6 @@
 }
 
 test_rebase_am_only --whitespace=fix
-test_rebase_am_only --ignore-whitespace
-test_rebase_am_only --committer-date-is-author-date
 test_rebase_am_only -C4
 
 test_expect_success REBASE_P '--preserve-merges incompatible with --signoff' '
diff --git a/t/t3436-rebase-more-options.sh b/t/t3436-rebase-more-options.sh
new file mode 100755
index 0000000..996e827
--- /dev/null
+++ b/t/t3436-rebase-more-options.sh
@@ -0,0 +1,180 @@
+#!/bin/sh
+#
+# Copyright (c) 2019 Rohit Ashiwal
+#
+
+test_description='tests to ensure compatibility between am and interactive backends'
+
+. ./test-lib.sh
+
+. "$TEST_DIRECTORY"/lib-rebase.sh
+
+GIT_AUTHOR_DATE="1999-04-02T08:03:20+05:30"
+export GIT_AUTHOR_DATE
+
+# This is a special case in which both am and interactive backends
+# provide the same output. It was done intentionally because
+# both the backends fall short of optimal behaviour.
+test_expect_success 'setup' '
+	git checkout -b topic &&
+	test_write_lines "line 1" "	line 2" "line 3" >file &&
+	git add file &&
+	git commit -m "add file" &&
+
+	test_write_lines "line 1" "new line 2" "line 3" >file &&
+	git commit -am "update file" &&
+	git tag side &&
+	test_commit commit1 foo foo1 &&
+	test_commit commit2 foo foo2 &&
+	test_commit commit3 foo foo3 &&
+
+	git checkout --orphan master &&
+	rm foo &&
+	test_write_lines "line 1" "        line 2" "line 3" >file &&
+	git commit -am "add file" &&
+	git tag main &&
+
+	mkdir test-bin &&
+	write_script test-bin/git-merge-test <<-\EOF
+	exec git merge-recursive "$@"
+	EOF
+'
+
+test_expect_success '--ignore-whitespace works with apply backend' '
+	test_must_fail git rebase --apply main side &&
+	git rebase --abort &&
+	git rebase --apply --ignore-whitespace main side &&
+	git diff --exit-code side
+'
+
+test_expect_success '--ignore-whitespace works with merge backend' '
+	test_must_fail git rebase --merge main side &&
+	git rebase --abort &&
+	git rebase --merge --ignore-whitespace main side &&
+	git diff --exit-code side
+'
+
+test_expect_success '--ignore-whitespace is remembered when continuing' '
+	(
+		set_fake_editor &&
+		FAKE_LINES="break 1" git rebase -i --ignore-whitespace \
+			main side &&
+		git rebase --continue
+	) &&
+	git diff --exit-code side
+'
+
+test_ctime_is_atime () {
+	git log $1 --format=%ai >authortime &&
+	git log $1 --format=%ci >committertime &&
+	test_cmp authortime committertime
+}
+
+test_expect_success '--committer-date-is-author-date works with apply backend' '
+	GIT_AUTHOR_DATE="@1234 +0300" git commit --amend --reset-author &&
+	git rebase --apply --committer-date-is-author-date HEAD^ &&
+	test_ctime_is_atime -1
+'
+
+test_expect_success '--committer-date-is-author-date works with merge backend' '
+	GIT_AUTHOR_DATE="@1234 +0300" git commit --amend --reset-author &&
+	git rebase -m --committer-date-is-author-date HEAD^ &&
+	test_ctime_is_atime -1
+'
+
+test_expect_success '--committer-date-is-author-date works with rebase -r' '
+	git checkout side &&
+	GIT_AUTHOR_DATE="@1234 +0300" git merge --no-ff commit3 &&
+	git rebase -r --root --committer-date-is-author-date &&
+	test_ctime_is_atime
+'
+
+test_expect_success '--committer-date-is-author-date works when forking merge' '
+	git checkout side &&
+	GIT_AUTHOR_DATE="@1234 +0300" git merge --no-ff commit3 &&
+	PATH="./test-bin:$PATH" git rebase -r --root --strategy=test \
+					--committer-date-is-author-date &&
+	test_ctime_is_atime
+'
+
+test_expect_success '--committer-date-is-author-date works when committing conflict resolution' '
+	git checkout commit2 &&
+	GIT_AUTHOR_DATE="@1980 +0000" git commit --amend --only --reset-author &&
+	test_must_fail git rebase -m --committer-date-is-author-date \
+		--onto HEAD^^ HEAD^ &&
+	echo resolved > foo &&
+	git add foo &&
+	git rebase --continue &&
+	test_ctime_is_atime -1
+'
+
+# Checking for +0000 in the author date is sufficient since the
+# default timezone is UTC but the timezone used while committing is
+# +0530. The inverted logic in the grep is necessary to check all the
+# author dates in the file.
+test_atime_is_ignored () {
+	git log $1 --format=%ai >authortime &&
+	! grep -v +0000 authortime
+}
+
+test_expect_success '--reset-author-date works with apply backend' '
+	git commit --amend --date="$GIT_AUTHOR_DATE" &&
+	git rebase --apply --reset-author-date HEAD^ &&
+	test_atime_is_ignored -1
+'
+
+test_expect_success '--reset-author-date works with merge backend' '
+	git commit --amend --date="$GIT_AUTHOR_DATE" &&
+	git rebase --reset-author-date -m HEAD^ &&
+	test_atime_is_ignored -1
+'
+
+test_expect_success '--reset-author-date works after conflict resolution' '
+	test_must_fail git rebase --reset-author-date -m \
+		--onto commit2^^ commit2^ commit2 &&
+	echo resolved >foo &&
+	git add foo &&
+	git rebase --continue &&
+	test_atime_is_ignored -1
+'
+
+test_expect_success '--reset-author-date works with rebase -r' '
+	git checkout side &&
+	git merge --no-ff commit3 &&
+	git rebase -r --root --reset-author-date &&
+	test_atime_is_ignored
+'
+
+test_expect_success '--reset-author-date with --committer-date-is-author-date works' '
+	test_must_fail git rebase -m --committer-date-is-author-date \
+		--reset-author-date --onto commit2^^ commit2^ commit3 &&
+	git checkout --theirs foo &&
+	git add foo &&
+	git rebase --continue &&
+	test_ctime_is_atime -2 &&
+	test_atime_is_ignored -2
+'
+
+test_expect_success '--reset-author-date --committer-date-is-author-date works when forking merge' '
+	GIT_SEQUENCE_EDITOR="echo \"merge -C $(git rev-parse HEAD) commit3\">" \
+		PATH="./test-bin:$PATH" git rebase -i --strategy=test \
+				--reset-author-date \
+				--committer-date-is-author-date side side &&
+	test_ctime_is_atime -1 &&
+	test_atime_is_ignored -1
+ '
+
+test_expect_success '--ignore-date is an alias for --reset-author-date' '
+	git commit --amend --date="$GIT_AUTHOR_DATE" &&
+	git rebase --apply --ignore-date HEAD^ &&
+	git commit --allow-empty -m empty --date="$GIT_AUTHOR_DATE" &&
+	git rebase -m --ignore-date HEAD^ &&
+	test_atime_is_ignored -2
+'
+
+# This must be the last test in this file
+test_expect_success '$EDITOR and friends are unchanged' '
+	test_editor_unchanged
+'
+
+test_done
diff --git a/t/t3500-cherry.sh b/t/t3500-cherry.sh
index f038f34..2b8d9cb 100755
--- a/t/t3500-cherry.sh
+++ b/t/t3500-cherry.sh
@@ -55,4 +55,27 @@
      expr "$(echo $(git cherry master my-topic-branch) )" : "+ [^ ]* - .*"
 '
 
+test_expect_success 'cherry ignores whitespace' '
+	git switch --orphan=upstream-with-space &&
+	test_commit initial file &&
+	>expect &&
+	git switch --create=feature-without-space &&
+
+	# A spaceless file on the feature branch.  Expect a match upstream.
+	printf space >file &&
+	git add file &&
+	git commit -m"file without space" &&
+	git log --format="- %H" -1 >>expect &&
+
+	# A further change.  Should not match upstream.
+	test_commit change file &&
+	git log --format="+ %H" -1 >>expect &&
+
+	git switch upstream-with-space &&
+	# Same as the spaceless file, just with spaces and on upstream.
+	test_commit "file with space" file "s p a c e" file-with-space &&
+	git cherry upstream-with-space feature-without-space >actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
index f107622..a21adcf 100755
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -283,12 +283,12 @@
 	a
 	=======
 	c
-	>>>>>>> objid picked
+	>>>>>>> objid (picked)
 	EOF
 
 	test_must_fail git cherry-pick picked &&
 
-	sed "s/[a-f0-9]*\.\.\./objid/" foo >actual &&
+	sed "s/[a-f0-9]* (/objid (/" foo >actual &&
 	test_cmp expected actual
 '
 
@@ -298,16 +298,16 @@
 	cat <<-EOF >expected &&
 	<<<<<<< HEAD
 	a
-	||||||| parent of objid picked
+	||||||| parent of objid (picked)
 	b
 	=======
 	c
-	>>>>>>> objid picked
+	>>>>>>> objid (picked)
 	EOF
 
 	test_must_fail git cherry-pick picked &&
 
-	sed "s/[a-f0-9]*\.\.\./objid/" foo >actual &&
+	sed "s/[a-f0-9]* (/objid (/" foo >actual &&
 	test_cmp expected actual
 '
 
@@ -319,7 +319,7 @@
 	a
 	=======
 	b
-	>>>>>>> parent of objid picked
+	>>>>>>> parent of objid (picked)
 	EOF
 	{
 		git checkout picked -- foo &&
@@ -345,7 +345,7 @@
 	test_must_fail git update-index --refresh -q &&
 	test_must_fail git diff-index --exit-code HEAD &&
 	test_cmp expected-stages actual-stages &&
-	sed "s/[a-f0-9]*\.\.\./objid/" foo >actual &&
+	sed "s/[a-f0-9]* (/objid (/" foo >actual &&
 	test_cmp expected actual
 '
 
@@ -429,16 +429,16 @@
 	cat <<-EOF >expected &&
 	<<<<<<< HEAD
 	a
-	||||||| objid picked
+	||||||| objid (picked)
 	c
 	=======
 	b
-	>>>>>>> parent of objid picked
+	>>>>>>> parent of objid (picked)
 	EOF
 
 	test_must_fail git revert picked &&
 
-	sed "s/[a-f0-9]*\.\.\./objid/" foo >actual &&
+	sed "s/[a-f0-9]* (/objid (/" foo >actual &&
 	test_cmp expected actual
 '
 
diff --git a/t/t4013-diff-various.sh b/t/t4013-diff-various.sh
index 3f60f7d..5c7b012 100755
--- a/t/t4013-diff-various.sh
+++ b/t/t4013-diff-various.sh
@@ -130,27 +130,45 @@
 EOF
 
 process_diffs () {
-	_x04="[0-9a-f][0-9a-f][0-9a-f][0-9a-f]" &&
-	_x07="$_x05[0-9a-f][0-9a-f]" &&
-	sed -e "s/$OID_REGEX/$ZERO_OID/g" \
-	    -e "s/From $_x40 /From $ZERO_OID /" \
-	    -e "s/from $_x40)/from $ZERO_OID)/" \
-	    -e "s/commit $_x40\$/commit $ZERO_OID/" \
-	    -e "s/commit $_x40 (/commit $ZERO_OID (/" \
-	    -e "s/$_x40 $_x40 $_x40/$ZERO_OID $ZERO_OID $ZERO_OID/" \
-	    -e "s/$_x40 $_x40 /$ZERO_OID $ZERO_OID /" \
-	    -e "s/^$_x40 $_x40$/$ZERO_OID $ZERO_OID/" \
-	    -e "s/^$_x40 /$ZERO_OID /" \
-	    -e "s/^$_x40$/$ZERO_OID/" \
-	    -e "s/$_x07\.\.$_x07/fffffff..fffffff/g" \
-	    -e "s/$_x07,$_x07\.\.$_x07/fffffff,fffffff..fffffff/g" \
-	    -e "s/$_x07 $_x07 $_x07/fffffff fffffff fffffff/g" \
-	    -e "s/$_x07 $_x07 /fffffff fffffff /g" \
-	    -e "s/Merge: $_x07 $_x07/Merge: fffffff fffffff/g" \
-	    -e "s/$_x07\.\.\./fffffff.../g" \
-	    -e "s/ $_x04\.\.\./ ffff.../g" \
-	    -e "s/ $_x04/ ffff/g" \
-	    "$1"
+	perl -e '
+		my $oid_length = length($ARGV[0]);
+		my $x40 = "[0-9a-f]{40}";
+		my $xab = "[0-9a-f]{4,16}";
+		my $orx = "[0-9a-f]" x $oid_length;
+
+		sub munge_oid {
+			my ($oid) = @_;
+			my $x;
+
+			return "" unless length $oid;
+
+			if ($oid =~ /^(100644|100755|120000)$/) {
+				return $oid;
+			}
+
+			if ($oid =~ /^0*$/) {
+				$x = "0";
+			} else {
+				$x = "f";
+			}
+
+			if (length($oid) == 40) {
+				return $x x $oid_length;
+			} else {
+				return $x x length($oid);
+			}
+		}
+
+		while (<STDIN>) {
+			s/($orx)/munge_oid($1)/ge;
+			s/From ($x40)( |\))/"From " . munge_oid($1) . $2/ge;
+			s/commit ($x40)($| \(from )($x40?)/"commit " .  munge_oid($1) . $2 . munge_oid($3)/ge;
+			s/\b($x40)( |\.\.|$)/munge_oid($1) . $2/ge;
+			s/^($x40)($| )/munge_oid($1) . $2/e;
+			s/($xab)(\.\.|,| |\.\.\.|$)/munge_oid($1) . $2/ge;
+			print;
+		}
+	' "$ZERO_OID" <"$1"
 }
 
 V=$(git version | sed -e 's/^git version //' -e 's/\./\\./g')
@@ -221,6 +239,9 @@
 :noellipses diff-tree --root -r --abbrev=4 initial
 diff-tree -p initial
 diff-tree --root -p initial
+diff-tree --root -p --abbrev=10 initial
+diff-tree --root -p --full-index initial
+diff-tree --root -p --full-index --abbrev=10 initial
 diff-tree --patch-with-stat initial
 diff-tree --root --patch-with-stat initial
 diff-tree --patch-with-raw initial
@@ -297,6 +318,9 @@
 log --root -c --patch-with-stat --summary master
 # improved by Timo's patch
 log --root --cc --patch-with-stat --summary master
+log --no-diff-merges -p --first-parent master
+log --diff-merges=off -p --first-parent master
+log --first-parent --diff-merges=off -p master
 log -p --first-parent master
 log -m -p --first-parent master
 log -m -p master
diff --git a/t/t4013/diff.diff-tree_--root_-p_--abbrev=10_initial b/t/t4013/diff.diff-tree_--root_-p_--abbrev=10_initial
new file mode 100644
index 0000000..7518a90
--- /dev/null
+++ b/t/t4013/diff.diff-tree_--root_-p_--abbrev=10_initial
@@ -0,0 +1,29 @@
+$ git diff-tree --root -p --abbrev=10 initial
+444ac553ac7612cc88969031b02b3767fb8a353a
+diff --git a/dir/sub b/dir/sub
+new file mode 100644
+index 0000000000..35d242ba79
+--- /dev/null
++++ b/dir/sub
+@@ -0,0 +1,2 @@
++A
++B
+diff --git a/file0 b/file0
+new file mode 100644
+index 0000000000..01e79c32a8
+--- /dev/null
++++ b/file0
+@@ -0,0 +1,3 @@
++1
++2
++3
+diff --git a/file2 b/file2
+new file mode 100644
+index 0000000000..01e79c32a8
+--- /dev/null
++++ b/file2
+@@ -0,0 +1,3 @@
++1
++2
++3
+$
diff --git a/t/t4013/diff.diff-tree_--root_-p_--full-index_--abbrev=10_initial b/t/t4013/diff.diff-tree_--root_-p_--full-index_--abbrev=10_initial
new file mode 100644
index 0000000..69f913f
--- /dev/null
+++ b/t/t4013/diff.diff-tree_--root_-p_--full-index_--abbrev=10_initial
@@ -0,0 +1,29 @@
+$ git diff-tree --root -p --full-index --abbrev=10 initial
+444ac553ac7612cc88969031b02b3767fb8a353a
+diff --git a/dir/sub b/dir/sub
+new file mode 100644
+index 0000000000000000000000000000000000000000..35d242ba79ae89ac695e26b3d4c27a8e6f028f9e
+--- /dev/null
++++ b/dir/sub
+@@ -0,0 +1,2 @@
++A
++B
+diff --git a/file0 b/file0
+new file mode 100644
+index 0000000000000000000000000000000000000000..01e79c32a8c99c557f0757da7cb6d65b3414466d
+--- /dev/null
++++ b/file0
+@@ -0,0 +1,3 @@
++1
++2
++3
+diff --git a/file2 b/file2
+new file mode 100644
+index 0000000000000000000000000000000000000000..01e79c32a8c99c557f0757da7cb6d65b3414466d
+--- /dev/null
++++ b/file2
+@@ -0,0 +1,3 @@
++1
++2
++3
+$
diff --git a/t/t4013/diff.diff-tree_--root_-p_--full-index_initial b/t/t4013/diff.diff-tree_--root_-p_--full-index_initial
new file mode 100644
index 0000000..1b0b671
--- /dev/null
+++ b/t/t4013/diff.diff-tree_--root_-p_--full-index_initial
@@ -0,0 +1,29 @@
+$ git diff-tree --root -p --full-index initial
+444ac553ac7612cc88969031b02b3767fb8a353a
+diff --git a/dir/sub b/dir/sub
+new file mode 100644
+index 0000000000000000000000000000000000000000..35d242ba79ae89ac695e26b3d4c27a8e6f028f9e
+--- /dev/null
++++ b/dir/sub
+@@ -0,0 +1,2 @@
++A
++B
+diff --git a/file0 b/file0
+new file mode 100644
+index 0000000000000000000000000000000000000000..01e79c32a8c99c557f0757da7cb6d65b3414466d
+--- /dev/null
++++ b/file0
+@@ -0,0 +1,3 @@
++1
++2
++3
+diff --git a/file2 b/file2
+new file mode 100644
+index 0000000000000000000000000000000000000000..01e79c32a8c99c557f0757da7cb6d65b3414466d
+--- /dev/null
++++ b/file2
+@@ -0,0 +1,3 @@
++1
++2
++3
+$
diff --git a/t/t4013/diff.log_--diff-merges=off_-p_--first-parent_master b/t/t4013/diff.log_--diff-merges=off_-p_--first-parent_master
new file mode 100644
index 0000000..194e893
--- /dev/null
+++ b/t/t4013/diff.log_--diff-merges=off_-p_--first-parent_master
@@ -0,0 +1,78 @@
+$ git log --diff-merges=off -p --first-parent master
+commit 59d314ad6f356dd08601a4cd5e530381da3e3c64
+Merge: 9a6d494 c7a2ab9
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:04:00 2006 +0000
+
+    Merge branch 'side'
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+diff --git a/dir/sub b/dir/sub
+index 8422d40..cead32e 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -2,3 +2,5 @@ A
+ B
+ C
+ D
++E
++F
+diff --git a/file1 b/file1
+new file mode 100644
+index 0000000..b1e6722
+--- /dev/null
++++ b/file1
+@@ -0,0 +1,3 @@
++A
++B
++C
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+diff --git a/dir/sub b/dir/sub
+index 35d242b..8422d40 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -1,2 +1,4 @@
+ A
+ B
++C
++D
+diff --git a/file0 b/file0
+index 01e79c3..b414108 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++4
++5
++6
+diff --git a/file2 b/file2
+deleted file mode 100644
+index 01e79c3..0000000
+--- a/file2
++++ /dev/null
+@@ -1,3 +0,0 @@
+-1
+-2
+-3
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+$
diff --git a/t/t4013/diff.log_--first-parent_--diff-merges=off_-p_master b/t/t4013/diff.log_--first-parent_--diff-merges=off_-p_master
new file mode 100644
index 0000000..5d7461a
--- /dev/null
+++ b/t/t4013/diff.log_--first-parent_--diff-merges=off_-p_master
@@ -0,0 +1,78 @@
+$ git log --first-parent --diff-merges=off -p master
+commit 80e25ffa65bcdbe82ef654b4d06dbbde7945c37f
+Merge: 9a6d494 c7a2ab9
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:04:00 2006 +0000
+
+    Merge branch 'side'
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+diff --git a/dir/sub b/dir/sub
+index 8422d40..cead32e 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -2,3 +2,5 @@ A
+ B
+ C
+ D
++E
++F
+diff --git a/file1 b/file1
+new file mode 100644
+index 0000000..b1e6722
+--- /dev/null
++++ b/file1
+@@ -0,0 +1,3 @@
++A
++B
++C
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+diff --git a/dir/sub b/dir/sub
+index 35d242b..8422d40 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -1,2 +1,4 @@
+ A
+ B
++C
++D
+diff --git a/file0 b/file0
+index 01e79c3..b414108 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++4
++5
++6
+diff --git a/file2 b/file2
+deleted file mode 100644
+index 01e79c3..0000000
+--- a/file2
++++ /dev/null
+@@ -1,3 +0,0 @@
+-1
+-2
+-3
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+$
diff --git a/t/t4013/diff.log_--no-diff-merges_-p_--first-parent_master b/t/t4013/diff.log_--no-diff-merges_-p_--first-parent_master
new file mode 100644
index 0000000..5970022
--- /dev/null
+++ b/t/t4013/diff.log_--no-diff-merges_-p_--first-parent_master
@@ -0,0 +1,78 @@
+$ git log --no-diff-merges -p --first-parent master
+commit 59d314ad6f356dd08601a4cd5e530381da3e3c64
+Merge: 9a6d494 c7a2ab9
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:04:00 2006 +0000
+
+    Merge branch 'side'
+
+commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:02:00 2006 +0000
+
+    Third
+
+diff --git a/dir/sub b/dir/sub
+index 8422d40..cead32e 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -2,3 +2,5 @@ A
+ B
+ C
+ D
++E
++F
+diff --git a/file1 b/file1
+new file mode 100644
+index 0000000..b1e6722
+--- /dev/null
++++ b/file1
+@@ -0,0 +1,3 @@
++A
++B
++C
+
+commit 1bde4ae5f36c8d9abe3a0fce0c6aab3c4a12fe44
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:01:00 2006 +0000
+
+    Second
+    
+    This is the second commit.
+
+diff --git a/dir/sub b/dir/sub
+index 35d242b..8422d40 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -1,2 +1,4 @@
+ A
+ B
++C
++D
+diff --git a/file0 b/file0
+index 01e79c3..b414108 100644
+--- a/file0
++++ b/file0
+@@ -1,3 +1,6 @@
+ 1
+ 2
+ 3
++4
++5
++6
+diff --git a/file2 b/file2
+deleted file mode 100644
+index 01e79c3..0000000
+--- a/file2
++++ /dev/null
+@@ -1,3 +0,0 @@
+-1
+-2
+-3
+
+commit 444ac553ac7612cc88969031b02b3767fb8a353a
+Author: A U Thor <author@example.com>
+Date:   Mon Jun 26 00:00:00 2006 +0000
+
+    Initial
+$
diff --git a/t/t4013/diff.log_-p_--first-parent_master b/t/t4013/diff.log_-p_--first-parent_master
index 3fc896d..28840eb 100644
--- a/t/t4013/diff.log_-p_--first-parent_master
+++ b/t/t4013/diff.log_-p_--first-parent_master
@@ -6,6 +6,28 @@
 
     Merge branch 'side'
 
+diff --git a/dir/sub b/dir/sub
+index cead32e..992913c 100644
+--- a/dir/sub
++++ b/dir/sub
+@@ -4,3 +4,5 @@ C
+ D
+ E
+ F
++1
++2
+diff --git a/file0 b/file0
+index b414108..10a8a9f 100644
+--- a/file0
++++ b/file0
+@@ -4,3 +4,6 @@
+ 4
+ 5
+ 6
++A
++B
++C
+
 commit 9a6d4949b6b76956d9d5e26f2791ec2ceff5fdc0
 Author: A U Thor <author@example.com>
 Date:   Mon Jun 26 00:02:00 2006 +0000
diff --git a/t/t4018/fortran-block-data b/t/t4018/fortran-block-data
new file mode 100644
index 0000000..63d4e21
--- /dev/null
+++ b/t/t4018/fortran-block-data
@@ -0,0 +1,5 @@
+       BLOCK DATA RIGHT
+       
+       COMMON /B/ C, ChangeMe
+       DATA C, ChangeMe  / 2.0, 6.0 / 
+       END 
diff --git a/t/t4018/fortran-comment b/t/t4018/fortran-comment
new file mode 100644
index 0000000..7b10d17
--- /dev/null
+++ b/t/t4018/fortran-comment
@@ -0,0 +1,13 @@
+      module a
+
+      contains
+
+      ! subroutine wrong
+      subroutine RIGHT
+      ! subroutine wrong
+
+      real ChangeMe
+
+      end subroutine RIGHT
+
+      end module a
diff --git a/t/t4018/fortran-comment-keyword b/t/t4018/fortran-comment-keyword
new file mode 100644
index 0000000..e9206a5
--- /dev/null
+++ b/t/t4018/fortran-comment-keyword
@@ -0,0 +1,14 @@
+      module a
+
+      contains
+
+      subroutine RIGHT (funcA, funcB)
+
+      real funcA  ! grid function a
+      real funcB  ! grid function b
+
+      real ChangeMe
+
+      end subroutine RIGHT
+
+      end module a
diff --git a/t/t4018/fortran-comment-legacy b/t/t4018/fortran-comment-legacy
new file mode 100644
index 0000000..53cd062
--- /dev/null
+++ b/t/t4018/fortran-comment-legacy
@@ -0,0 +1,13 @@
+      module a
+
+      contains
+
+C subroutine wrong
+      subroutine RIGHT
+C subroutine wrong
+
+      real ChangeMe
+
+      end subroutine RIGHT
+
+      end module a
diff --git a/t/t4018/fortran-comment-legacy-star b/t/t4018/fortran-comment-legacy-star
new file mode 100644
index 0000000..2cbcdc3
--- /dev/null
+++ b/t/t4018/fortran-comment-legacy-star
@@ -0,0 +1,13 @@
+      module a
+
+      contains
+
+* subroutine wrong
+      subroutine RIGHT
+* subroutine wrong
+
+      real ChangeMe
+
+      end subroutine RIGHT
+
+      end module a
diff --git a/t/t4018/fortran-external-function b/t/t4018/fortran-external-function
new file mode 100644
index 0000000..5a2d85d
--- /dev/null
+++ b/t/t4018/fortran-external-function
@@ -0,0 +1,9 @@
+function RIGHT(a, b) result(c)
+
+integer, intent(in) :: ChangeMe
+integer, intent(in) :: b
+integer, intent(out) :: c
+
+c = a+b
+
+end function RIGHT
diff --git a/t/t4018/fortran-external-subroutine b/t/t4018/fortran-external-subroutine
new file mode 100644
index 0000000..4ce85fe
--- /dev/null
+++ b/t/t4018/fortran-external-subroutine
@@ -0,0 +1,5 @@
+subroutine RIGHT
+
+real ChangeMe
+
+end subroutine RIGHT
diff --git a/t/t4018/fortran-module b/t/t4018/fortran-module
new file mode 100644
index 0000000..c4b737d
--- /dev/null
+++ b/t/t4018/fortran-module
@@ -0,0 +1,5 @@
+module RIGHT
+
+use ChangeMe
+
+end module RIGHT
diff --git a/t/t4018/fortran-module-procedure b/t/t4018/fortran-module-procedure
new file mode 100644
index 0000000..1ce6d85
--- /dev/null
+++ b/t/t4018/fortran-module-procedure
@@ -0,0 +1,13 @@
+ module RIGHT
+
+   implicit none
+   private
+
+   interface letters  ! generic interface
+      module procedure aaaa, &
+                       bbbb, &
+                       ChangeMe, &
+                       dddd
+   end interface
+   
+end module RIGHT
diff --git a/t/t4018/fortran-program b/t/t4018/fortran-program
new file mode 100644
index 0000000..4616895
--- /dev/null
+++ b/t/t4018/fortran-program
@@ -0,0 +1,5 @@
+program RIGHT
+
+call ChangeMe
+
+end program RIGHT
diff --git a/t/t4140-apply-ita.sh b/t/t4140-apply-ita.sh
new file mode 100755
index 0000000..c614eaf
--- /dev/null
+++ b/t/t4140-apply-ita.sh
@@ -0,0 +1,56 @@
+#!/bin/sh
+
+test_description='git apply of i-t-a file'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	test_write_lines 1 2 3 4 5 >blueprint &&
+
+	cat blueprint >test-file &&
+	git add -N test-file &&
+	git diff >creation-patch &&
+	grep "new file mode 100644" creation-patch &&
+
+	rm -f test-file &&
+	git diff >deletion-patch &&
+	grep "deleted file mode 100644" deletion-patch
+'
+
+test_expect_success 'apply creation patch to ita path (--cached)' '
+	git rm -f test-file &&
+	cat blueprint >test-file &&
+	git add -N test-file &&
+
+	git apply --cached creation-patch &&
+	git cat-file blob :test-file >actual &&
+	test_cmp blueprint actual
+'
+
+test_expect_success 'apply creation patch to ita path (--index)' '
+	git rm -f test-file &&
+	cat blueprint >test-file &&
+	git add -N test-file &&
+	rm -f test-file &&
+
+	test_must_fail git apply --index creation-patch
+'
+
+test_expect_success 'apply deletion patch to ita path (--cached)' '
+	git rm -f test-file &&
+	cat blueprint >test-file &&
+	git add -N test-file &&
+
+	git apply --cached deletion-patch &&
+	test_must_fail git ls-files --stage --error-unmatch test-file
+'
+
+test_expect_success 'apply deletion patch to ita path (--index)' '
+	cat blueprint >test-file &&
+	git add -N test-file &&
+
+	test_must_fail git apply --index deletion-patch &&
+	git ls-files --stage --error-unmatch test-file
+'
+
+test_done
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
index a093059..56d34ed 100755
--- a/t/t4202-log.sh
+++ b/t/t4202-log.sh
@@ -1850,6 +1850,16 @@
 	test_must_be_empty actual
 '
 
+test_expect_success 'do not default to HEAD with ignored object on cmdline' '
+	git log --ignore-missing $ZERO_OID >actual &&
+	test_must_be_empty actual
+'
+
+test_expect_success 'do not default to HEAD with ignored object on stdin' '
+	echo $ZERO_OID | git log --ignore-missing --stdin >actual &&
+	test_must_be_empty actual
+'
+
 test_expect_success 'set up --source tests' '
 	git checkout --orphan source-a &&
 	test_commit one &&
diff --git a/t/t4216-log-bloom.sh b/t/t4216-log-bloom.sh
index c21cc16..4bb9e9d 100755
--- a/t/t4216-log-bloom.sh
+++ b/t/t4216-log-bloom.sh
@@ -30,12 +30,17 @@
 	rm file_to_be_deleted &&
 	git add . &&
 	git commit -m "file removed" &&
-	git commit-graph write --reachable --changed-paths
+	git commit-graph write --reachable --changed-paths &&
+
+	test_oid_cache <<-EOF
+	oid_version sha1:1
+	oid_version sha256:2
+	EOF
 '
 graph_read_expect () {
 	NUM_CHUNKS=5
 	cat >expect <<- EOF
-	header: 43475048 1 1 $NUM_CHUNKS 0
+	header: 43475048 1 $(test_oid oid_version) $NUM_CHUNKS 0
 	num_commits: $1
 	chunks: oid_fanout oid_lookup commit_metadata bloom_indexes bloom_data
 	EOF
diff --git a/t/t5318-commit-graph.sh b/t/t5318-commit-graph.sh
index 044cf8a..2ed0c15 100755
--- a/t/t5318-commit-graph.sh
+++ b/t/t5318-commit-graph.sh
@@ -10,7 +10,12 @@
 	cd "$TRASH_DIRECTORY/full" &&
 	git init &&
 	git config core.commitGraph true &&
-	objdir=".git/objects"
+	objdir=".git/objects" &&
+
+	test_oid_cache <<-EOF
+	oid_version sha1:1
+	oid_version sha256:2
+	EOF
 '
 
 test_expect_success POSIXPERM 'tweak umask for modebit tests' '
@@ -77,7 +82,7 @@
 		NUM_CHUNKS=$((3 + $(echo "$2" | wc -w)))
 	fi
 	cat >expect <<- EOF
-	header: 43475048 1 1 $NUM_CHUNKS 0
+	header: 43475048 1 $(test_oid oid_version) $NUM_CHUNKS 0
 	num_commits: $1
 	chunks: oid_fanout oid_lookup commit_metadata$OPTIONAL
 	EOF
@@ -412,6 +417,35 @@
 	)
 '
 
+test_expect_success 'warn on improper hash version' '
+	git init --object-format=sha1 sha1 &&
+	(
+		cd sha1 &&
+		test_commit 1 &&
+		git commit-graph write --reachable &&
+		mv .git/objects/info/commit-graph ../cg-sha1
+	) &&
+	git init --object-format=sha256 sha256 &&
+	(
+		cd sha256 &&
+		test_commit 1 &&
+		git commit-graph write --reachable &&
+		mv .git/objects/info/commit-graph ../cg-sha256
+	) &&
+	(
+		cd sha1 &&
+		mv ../cg-sha256 .git/objects/info/commit-graph &&
+		git log -1 2>err &&
+		test_i18ngrep "commit-graph hash version 2 does not match version 1" err
+	) &&
+	(
+		cd sha256 &&
+		mv ../cg-sha1 .git/objects/info/commit-graph &&
+		git log -1 2>err &&
+		test_i18ngrep "commit-graph hash version 1 does not match version 2" err
+	)
+'
+
 # the verify tests below expect the commit-graph to contain
 # exactly the commits reachable from the commits/8 branch.
 # If the file changes the set of commits in the list, then the
diff --git a/t/t5319-multi-pack-index.sh b/t/t5319-multi-pack-index.sh
index 7dfff0f..43b1b5b 100755
--- a/t/t5319-multi-pack-index.sh
+++ b/t/t5319-multi-pack-index.sh
@@ -5,6 +5,8 @@
 
 objdir=.git/objects
 
+HASH_LEN=$(test_oid rawsz)
+
 midx_read_expect () {
 	NUM_PACKS=$1
 	NUM_OBJECTS=$2
@@ -13,7 +15,7 @@
 	EXTRA_CHUNKS="$5"
 	{
 		cat <<-EOF &&
-		header: 4d494458 1 $NUM_CHUNKS $NUM_PACKS
+		header: 4d494458 1 $HASH_LEN $NUM_CHUNKS $NUM_PACKS
 		chunks: pack-names oid-fanout oid-lookup object-offsets$EXTRA_CHUNKS
 		num_objects: $NUM_OBJECTS
 		packs:
@@ -46,7 +48,7 @@
 	test_path_is_missing pack/multi-pack-index
 '
 
-test_expect_success "Warn if a midx contains no oid" '
+test_expect_success SHA1 'warn if a midx contains no oid' '
 	cp "$TEST_DIRECTORY"/t5319/no-objects.midx $objdir/pack/multi-pack-index &&
 	test_must_fail git multi-pack-index verify &&
 	rm $objdir/pack/multi-pack-index
@@ -198,6 +200,40 @@
 
 compare_results_with_midx "twelve packs"
 
+test_expect_success 'warn on improper hash version' '
+	git init --object-format=sha1 sha1 &&
+	(
+		cd sha1 &&
+		git config core.multiPackIndex true &&
+		test_commit 1 &&
+		git repack -a &&
+		git multi-pack-index write &&
+		mv .git/objects/pack/multi-pack-index ../mpi-sha1
+	) &&
+	git init --object-format=sha256 sha256 &&
+	(
+		cd sha256 &&
+		git config core.multiPackIndex true &&
+		test_commit 1 &&
+		git repack -a &&
+		git multi-pack-index write &&
+		mv .git/objects/pack/multi-pack-index ../mpi-sha256
+	) &&
+	(
+		cd sha1 &&
+		mv ../mpi-sha256 .git/objects/pack/multi-pack-index &&
+		git log -1 2>err &&
+		test_i18ngrep "multi-pack-index hash version 2 does not match version 1" err
+	) &&
+	(
+		cd sha256 &&
+		mv ../mpi-sha1 .git/objects/pack/multi-pack-index &&
+		git log -1 2>err &&
+		test_i18ngrep "multi-pack-index hash version 1 does not match version 2" err
+	)
+'
+
+
 test_expect_success 'verify multi-pack-index success' '
 	git multi-pack-index verify --object-dir=$objdir
 '
@@ -243,7 +279,6 @@
 		"multi-pack-index signature"
 '
 
-HASH_LEN=$(test_oid rawsz)
 NUM_OBJECTS=74
 MIDX_BYTE_VERSION=4
 MIDX_BYTE_OID_VERSION=5
@@ -272,7 +307,7 @@
 '
 
 test_expect_success 'verify bad OID version' '
-	corrupt_midx_and_verify $MIDX_BYTE_OID_VERSION "\02" $objdir \
+	corrupt_midx_and_verify $MIDX_BYTE_OID_VERSION "\03" $objdir \
 		"hash version"
 '
 
@@ -642,6 +677,7 @@
 '
 
 test_expect_success 'repack --batch-size=0 repacks everything' '
+	cp -r dup dup2 &&
 	(
 		cd dup &&
 		rm .git/objects/pack/*.keep &&
@@ -661,4 +697,21 @@
 	)
 '
 
+test_expect_success 'repack --batch-size=<large> repacks everything' '
+	(
+		cd dup2 &&
+		rm .git/objects/pack/*.keep &&
+		ls .git/objects/pack/*idx >idx-list &&
+		test_line_count = 2 idx-list &&
+		git multi-pack-index repack --batch-size=2000000 &&
+		ls .git/objects/pack/*idx >idx-list &&
+		test_line_count = 3 idx-list &&
+		test-tool read-midx .git/objects | grep idx >midx-list &&
+		test_line_count = 3 midx-list &&
+		git multi-pack-index expire &&
+		ls -al .git/objects/pack/*idx >idx-list &&
+		test_line_count = 1 idx-list
+	)
+'
+
 test_done
diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh
index ea28d52..1821646 100755
--- a/t/t5324-split-commit-graph.sh
+++ b/t/t5324-split-commit-graph.sh
@@ -18,6 +18,9 @@
 
 	base sha1:1376
 	base sha256:1496
+
+	oid_version sha1:1
+	oid_version sha256:2
 	EOM
 '
 
@@ -28,7 +31,7 @@
 		NUM_BASE=$2
 	fi
 	cat >expect <<- EOF
-	header: 43475048 1 1 3 $NUM_BASE
+	header: 43475048 1 $(test_oid oid_version) 3 $NUM_BASE
 	num_commits: $1
 	chunks: oid_fanout oid_lookup commit_metadata
 	EOF
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 25695df..2a1abe9 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -543,13 +543,24 @@
 
 '
 
-test_expect_success 'fetch --dry-run' '
-
+test_expect_success 'fetch --dry-run does not touch FETCH_HEAD' '
 	rm -f .git/FETCH_HEAD &&
 	git fetch --dry-run . &&
 	! test -f .git/FETCH_HEAD
 '
 
+test_expect_success '--no-write-fetch-head does not touch FETCH_HEAD' '
+	rm -f .git/FETCH_HEAD &&
+	git fetch --no-write-fetch-head . &&
+	! test -f .git/FETCH_HEAD
+'
+
+test_expect_success '--write-fetch-head gets defeated by --dry-run' '
+	rm -f .git/FETCH_HEAD &&
+	git fetch --dry-run --write-fetch-head . &&
+	! test -f .git/FETCH_HEAD
+'
+
 test_expect_success "should be able to fetch with duplicate refspecs" '
 	mkdir dups &&
 	(
diff --git a/t/t5521-pull-options.sh b/t/t5521-pull-options.sh
index 159afa7..db1a381 100755
--- a/t/t5521-pull-options.sh
+++ b/t/t5521-pull-options.sh
@@ -85,6 +85,13 @@
 	test -s err)
 '
 
+test_expect_success 'git pull --no-write-fetch-head fails' '
+	mkdir clonedwfh &&
+	(cd clonedwfh && git init &&
+	test_expect_code 129 git pull --no-write-fetch-head "../parent" >out 2>err &&
+	test_must_be_empty out &&
+	test_i18ngrep "no-write-fetch-head" err)
+'
 
 test_expect_success 'git pull --force' '
 	mkdir clonedoldstyle &&
diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
index 8827c2e..5a01466 100755
--- a/t/t5616-partial-clone.sh
+++ b/t/t5616-partial-clone.sh
@@ -163,6 +163,22 @@
 	test_line_count = 0 observed.oids
 '
 
+test_expect_success 'partial clone with transfer.fsckobjects=1 works with submodules' '
+	test_create_repo submodule &&
+	test_commit -C submodule mycommit &&
+
+	test_create_repo src_with_sub &&
+	test_config -C src_with_sub uploadpack.allowfilter 1 &&
+	test_config -C src_with_sub uploadpack.allowanysha1inwant 1 &&
+
+	git -C src_with_sub submodule add "file://$(pwd)/submodule" mysub &&
+	git -C src_with_sub commit -m "commit with submodule" &&
+
+	git -c transfer.fsckobjects=1 \
+		clone --filter="blob:none" "file://$(pwd)/src_with_sub" dst &&
+	test_when_finished rm -rf dst
+'
+
 test_expect_success 'partial clone with transfer.fsckobjects=1 uses index-pack --fsck-objects' '
 	git init src &&
 	test_commit -C src x &&
diff --git a/t/t6000-rev-list-misc.sh b/t/t6000-rev-list-misc.sh
index 3bb0e4f..fc4d55d 100755
--- a/t/t6000-rev-list-misc.sh
+++ b/t/t6000-rev-list-misc.sh
@@ -128,8 +128,8 @@
 	test_cmp expect actual
 '
 
-test_expect_success '--bisect and --first-parent can not be combined' '
-	test_must_fail git rev-list --bisect --first-parent HEAD
+test_expect_success '--bisect and --first-parent can be combined' '
+	git rev-list --bisect --first-parent HEAD
 '
 
 test_expect_success '--header shows a NUL after each commit' '
diff --git a/t/t6002-rev-list-bisect.sh b/t/t6002-rev-list-bisect.sh
index a661408..b95a021 100755
--- a/t/t6002-rev-list-bisect.sh
+++ b/t/t6002-rev-list-bisect.sh
@@ -263,4 +263,49 @@
 	test_cmp expect.sorted actual.sorted
 '
 
+test_output_expect_success '--bisect --first-parent' 'git rev-list --bisect --first-parent E ^F' <<EOF
+e4
+EOF
+
+test_output_expect_success '--first-parent' 'git rev-list --first-parent E ^F' <<EOF
+E
+e1
+e2
+e3
+e4
+e5
+e6
+e7
+e8
+EOF
+
+test_output_expect_success '--bisect-vars --first-parent' 'git rev-list --bisect-vars --first-parent E ^F' <<EOF
+bisect_rev='e5'
+bisect_nr=4
+bisect_good=4
+bisect_bad=3
+bisect_all=9
+bisect_steps=2
+EOF
+
+test_expect_success '--bisect-all --first-parent' '
+	cat >expect.unsorted <<-EOF &&
+	$(git rev-parse E) (tag: E, dist=0)
+	$(git rev-parse e1) (tag: e1, dist=1)
+	$(git rev-parse e2) (tag: e2, dist=2)
+	$(git rev-parse e3) (tag: e3, dist=3)
+	$(git rev-parse e4) (tag: e4, dist=4)
+	$(git rev-parse e5) (tag: e5, dist=4)
+	$(git rev-parse e6) (tag: e6, dist=3)
+	$(git rev-parse e7) (tag: e7, dist=2)
+	$(git rev-parse e8) (tag: e8, dist=1)
+	EOF
+
+	# expect results to be ordered by distance (descending),
+	# commit hash (ascending)
+	sort -k4,4r -k1,1 expect.unsorted >expect &&
+	git rev-list --bisect-all --first-parent E ^F >actual &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t6018-rev-list-glob.sh b/t/t6018-rev-list-glob.sh
index bb5aeac..b31ff7e 100755
--- a/t/t6018-rev-list-glob.sh
+++ b/t/t6018-rev-list-glob.sh
@@ -345,6 +345,11 @@
 	test_must_be_empty actual
 '
 
+test_expect_success 'rev-list should succeed with empty output when ignoring missing' '
+	git rev-list --ignore-missing $ZERO_OID >actual &&
+	test_must_be_empty actual
+'
+
 test_expect_success 'shortlog accepts --glob/--tags/--remotes' '
 
 	compare shortlog "subspace/one subspace/two" --branches=subspace &&
diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index 36d9b2b..b886529 100755
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -243,32 +243,30 @@
 '
 
 # We want to automatically find the commit that
-# introduced "Another" into hello.
-test_expect_success \
-    '"git bisect run" simple case' \
-    'echo "#"\!"/bin/sh" > test_script.sh &&
-     echo "grep Another hello > /dev/null" >> test_script.sh &&
-     echo "test \$? -ne 0" >> test_script.sh &&
-     chmod +x test_script.sh &&
-     git bisect start &&
-     git bisect good $HASH1 &&
-     git bisect bad $HASH4 &&
-     git bisect run ./test_script.sh > my_bisect_log.txt &&
-     grep "$HASH3 is the first bad commit" my_bisect_log.txt &&
-     git bisect reset'
+# added "Another" into hello.
+test_expect_success '"git bisect run" simple case' '
+	write_script test_script.sh <<-\EOF &&
+	! grep Another hello >/dev/null
+	EOF
+	git bisect start &&
+	git bisect good $HASH1 &&
+	git bisect bad $HASH4 &&
+	git bisect run ./test_script.sh >my_bisect_log.txt &&
+	grep "$HASH3 is the first bad commit" my_bisect_log.txt &&
+	git bisect reset
+'
 
 # We want to automatically find the commit that
-# introduced "Ciao" into hello.
-test_expect_success \
-    '"git bisect run" with more complex "git bisect start"' \
-    'echo "#"\!"/bin/sh" > test_script.sh &&
-     echo "grep Ciao hello > /dev/null" >> test_script.sh &&
-     echo "test \$? -ne 0" >> test_script.sh &&
-     chmod +x test_script.sh &&
-     git bisect start $HASH4 $HASH1 &&
-     git bisect run ./test_script.sh > my_bisect_log.txt &&
-     grep "$HASH4 is the first bad commit" my_bisect_log.txt &&
-     git bisect reset'
+# added "Ciao" into hello.
+test_expect_success '"git bisect run" with more complex "git bisect start"' '
+	write_script test_script.sh <<-\EOF &&
+	! grep Ciao hello >/dev/null
+	EOF
+	git bisect start $HASH4 $HASH1 &&
+	git bisect run ./test_script.sh >my_bisect_log.txt &&
+	grep "$HASH4 is the first bad commit" my_bisect_log.txt &&
+	git bisect reset
+'
 
 # $HASH1 is good, $HASH5 is bad, we skip $HASH3
 # but $HASH4 is good,
@@ -295,24 +293,17 @@
 test_expect_success 'bisect run & skip: cannot tell between 2' '
 	add_line_into_file "6: Yet a line." hello &&
 	HASH6=$(git rev-parse --verify HEAD) &&
-	echo "#"\!"/bin/sh" > test_script.sh &&
-	echo "sed -ne \\\$p hello | grep Ciao > /dev/null && exit 125" >> test_script.sh &&
-	echo "grep line hello > /dev/null" >> test_script.sh &&
-	echo "test \$? -ne 0" >> test_script.sh &&
-	chmod +x test_script.sh &&
+	write_script test_script.sh <<-\EOF &&
+	sed -ne \$p hello | grep Ciao >/dev/null && exit 125
+	! grep line hello >/dev/null
+	EOF
 	git bisect start $HASH6 $HASH1 &&
-	if git bisect run ./test_script.sh > my_bisect_log.txt
-	then
-		echo Oops, should have failed.
-		false
-	else
-		test $? -eq 2 &&
-		grep "first bad commit could be any of" my_bisect_log.txt &&
-		! grep $HASH3 my_bisect_log.txt &&
-		! grep $HASH6 my_bisect_log.txt &&
-		grep $HASH4 my_bisect_log.txt &&
-		grep $HASH5 my_bisect_log.txt
-	fi
+	test_expect_code 2 git bisect run ./test_script.sh >my_bisect_log.txt &&
+	grep "first bad commit could be any of" my_bisect_log.txt &&
+	! grep $HASH3 my_bisect_log.txt &&
+	! grep $HASH6 my_bisect_log.txt &&
+	grep $HASH4 my_bisect_log.txt &&
+	grep $HASH5 my_bisect_log.txt
 '
 
 HASH7=
@@ -320,14 +311,13 @@
 	git bisect reset &&
 	add_line_into_file "7: Should be the last line." hello &&
 	HASH7=$(git rev-parse --verify HEAD) &&
-	echo "#"\!"/bin/sh" > test_script.sh &&
-	echo "sed -ne \\\$p hello | grep Ciao > /dev/null && exit 125" >> test_script.sh &&
-	echo "sed -ne \\\$p hello | grep day > /dev/null && exit 125" >> test_script.sh &&
-	echo "grep Yet hello > /dev/null" >> test_script.sh &&
-	echo "test \$? -ne 0" >> test_script.sh &&
-	chmod +x test_script.sh &&
+	write_script test_script.sh <<-\EOF &&
+	sed -ne \$p hello | grep Ciao >/dev/null && exit 125
+	sed -ne \$p hello | grep day >/dev/null && exit 125
+	! grep Yet hello >/dev/null
+	EOF
 	git bisect start $HASH7 $HASH1 &&
-	git bisect run ./test_script.sh > my_bisect_log.txt &&
+	git bisect run ./test_script.sh >my_bisect_log.txt &&
 	grep "$HASH6 is the first bad commit" my_bisect_log.txt
 '
 
@@ -458,6 +448,24 @@
 	grep "$SIDE_HASH5" merge_bases.txt
 '
 
+# We want to automatically find the merge that
+# added "line" into hello.
+test_expect_success '"git bisect run --first-parent" simple case' '
+	git rev-list --first-parent $B_HASH ^$HASH4 >first_parent_chain.txt &&
+	write_script test_script.sh <<-\EOF &&
+	grep $(git rev-parse HEAD) first_parent_chain.txt || exit -1
+	! grep line hello >/dev/null
+	EOF
+	git bisect start --first-parent &&
+	test_path_is_file ".git/BISECT_FIRST_PARENT" &&
+	git bisect good $HASH4 &&
+	git bisect bad $B_HASH &&
+	git bisect run ./test_script.sh >my_bisect_log.txt &&
+	grep "$B_HASH is the first bad commit" my_bisect_log.txt &&
+	git bisect reset &&
+	test_path_is_missing .git/BISECT_FIRST_PARENT
+'
+
 test_expect_success 'good merge bases when good and bad are siblings' '
 	git bisect start "$B_HASH" "$A_HASH" > my_bisect_log.txt &&
 	test_i18ngrep "merge base must be tested" my_bisect_log.txt &&
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index a83579f..58adee7 100755
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -776,61 +776,40 @@
 '
 
 test_expect_success '%(trailers:unfold) unfolds trailers' '
-	git for-each-ref --format="%(trailers:unfold)" refs/heads/master >actual &&
 	{
 		unfold <trailers
 		echo
 	} >expect &&
+	git for-each-ref --format="%(trailers:unfold)" refs/heads/master >actual &&
+	test_cmp expect actual &&
+	git for-each-ref --format="%(contents:trailers:unfold)" refs/heads/master >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success '%(trailers:only) shows only "key: value" trailers' '
-	git for-each-ref --format="%(trailers:only)" refs/heads/master >actual &&
 	{
 		grep -v patch.description <trailers &&
 		echo
 	} >expect &&
+	git for-each-ref --format="%(trailers:only)" refs/heads/master >actual &&
+	test_cmp expect actual &&
+	git for-each-ref --format="%(contents:trailers:only)" refs/heads/master >actual &&
 	test_cmp expect actual
 '
 
 test_expect_success '%(trailers:only) and %(trailers:unfold) work together' '
+	{
+		grep -v patch.description <trailers | unfold &&
+		echo
+	} >expect &&
 	git for-each-ref --format="%(trailers:only,unfold)" refs/heads/master >actual &&
-	git for-each-ref --format="%(trailers:unfold,only)" refs/heads/master >reverse &&
-	test_cmp actual reverse &&
-	{
-		grep -v patch.description <trailers | unfold &&
-		echo
-	} >expect &&
-	test_cmp expect actual
-'
-
-test_expect_success '%(contents:trailers:unfold) unfolds trailers' '
-	git for-each-ref --format="%(contents:trailers:unfold)" refs/heads/master >actual &&
-	{
-		unfold <trailers
-		echo
-	} >expect &&
-	test_cmp expect actual
-'
-
-test_expect_success '%(contents:trailers:only) shows only "key: value" trailers' '
-	git for-each-ref --format="%(contents:trailers:only)" refs/heads/master >actual &&
-	{
-		grep -v patch.description <trailers &&
-		echo
-	} >expect &&
-	test_cmp expect actual
-'
-
-test_expect_success '%(contents:trailers:only) and %(contents:trailers:unfold) work together' '
+	test_cmp expect actual &&
+	git for-each-ref --format="%(trailers:unfold,only)" refs/heads/master >actual &&
+	test_cmp actual actual &&
 	git for-each-ref --format="%(contents:trailers:only,unfold)" refs/heads/master >actual &&
-	git for-each-ref --format="%(contents:trailers:unfold,only)" refs/heads/master >reverse &&
-	test_cmp actual reverse &&
-	{
-		grep -v patch.description <trailers | unfold &&
-		echo
-	} >expect &&
-	test_cmp expect actual
+	test_cmp expect actual &&
+	git for-each-ref --format="%(contents:trailers:unfold,only)" refs/heads/master >actual &&
+	test_cmp actual actual
 '
 
 test_expect_success '%(trailers) rejects unknown trailers arguments' '
@@ -839,15 +818,16 @@
 	fatal: unknown %(trailers) argument: unsupported
 	EOF
 	test_must_fail git for-each-ref --format="%(trailers:unsupported)" 2>actual &&
+	test_i18ncmp expect actual &&
+	test_must_fail git for-each-ref --format="%(contents:trailers:unsupported)" 2>actual &&
 	test_i18ncmp expect actual
 '
 
-test_expect_success '%(contents:trailers) rejects unknown trailers arguments' '
-	# error message cannot be checked under i18n
+test_expect_success 'if arguments, %(contents:trailers) shows error if colon is missing' '
 	cat >expect <<-EOF &&
-	fatal: unknown %(trailers) argument: unsupported
+	fatal: unrecognized %(contents) argument: trailersonly
 	EOF
-	test_must_fail git for-each-ref --format="%(contents:trailers:unsupported)" 2>actual &&
+	test_must_fail git for-each-ref --format="%(contents:trailersonly)" 2>actual &&
 	test_i18ncmp expect actual
 '
 
diff --git a/t/t6020-merge-df.sh b/t/t6400-merge-df.sh
similarity index 100%
rename from t/t6020-merge-df.sh
rename to t/t6400-merge-df.sh
diff --git a/t/t6021-merge-criss-cross.sh b/t/t6401-merge-criss-cross.sh
similarity index 100%
rename from t/t6021-merge-criss-cross.sh
rename to t/t6401-merge-criss-cross.sh
diff --git a/t/t6022-merge-rename.sh b/t/t6402-merge-rename.sh
similarity index 100%
rename from t/t6022-merge-rename.sh
rename to t/t6402-merge-rename.sh
diff --git a/t/t6023-merge-file.sh b/t/t6403-merge-file.sh
similarity index 100%
rename from t/t6023-merge-file.sh
rename to t/t6403-merge-file.sh
diff --git a/t/t6024-recursive-merge.sh b/t/t6404-recursive-merge.sh
similarity index 100%
rename from t/t6024-recursive-merge.sh
rename to t/t6404-recursive-merge.sh
diff --git a/t/t6025-merge-symlinks.sh b/t/t6405-merge-symlinks.sh
similarity index 100%
rename from t/t6025-merge-symlinks.sh
rename to t/t6405-merge-symlinks.sh
diff --git a/t/t6026-merge-attr.sh b/t/t6406-merge-attr.sh
similarity index 100%
rename from t/t6026-merge-attr.sh
rename to t/t6406-merge-attr.sh
diff --git a/t/t6027-merge-binary.sh b/t/t6407-merge-binary.sh
similarity index 100%
rename from t/t6027-merge-binary.sh
rename to t/t6407-merge-binary.sh
diff --git a/t/t6028-merge-up-to-date.sh b/t/t6408-merge-up-to-date.sh
similarity index 100%
rename from t/t6028-merge-up-to-date.sh
rename to t/t6408-merge-up-to-date.sh
diff --git a/t/t6029-merge-subtree.sh b/t/t6409-merge-subtree.sh
similarity index 100%
rename from t/t6029-merge-subtree.sh
rename to t/t6409-merge-subtree.sh
diff --git a/t/t6031-merge-filemode.sh b/t/t6411-merge-filemode.sh
similarity index 100%
rename from t/t6031-merge-filemode.sh
rename to t/t6411-merge-filemode.sh
diff --git a/t/t6032-merge-large-rename.sh b/t/t6412-merge-large-rename.sh
similarity index 100%
rename from t/t6032-merge-large-rename.sh
rename to t/t6412-merge-large-rename.sh
diff --git a/t/t6033-merge-crlf.sh b/t/t6413-merge-crlf.sh
similarity index 100%
rename from t/t6033-merge-crlf.sh
rename to t/t6413-merge-crlf.sh
diff --git a/t/t6034-merge-rename-nocruft.sh b/t/t6414-merge-rename-nocruft.sh
similarity index 100%
rename from t/t6034-merge-rename-nocruft.sh
rename to t/t6414-merge-rename-nocruft.sh
diff --git a/t/t6035-merge-dir-to-symlink.sh b/t/t6415-merge-dir-to-symlink.sh
similarity index 100%
rename from t/t6035-merge-dir-to-symlink.sh
rename to t/t6415-merge-dir-to-symlink.sh
diff --git a/t/t6036-recursive-corner-cases.sh b/t/t6416-recursive-corner-cases.sh
similarity index 99%
rename from t/t6036-recursive-corner-cases.sh
rename to t/t6416-recursive-corner-cases.sh
index b3bf462..fd98989 100755
--- a/t/t6036-recursive-corner-cases.sh
+++ b/t/t6416-recursive-corner-cases.sh
@@ -452,7 +452,7 @@
 #
 # So choice 5 at least provides some kind of conflict for the original case,
 # and can merge cleanly as expected with D1 and E3.  It also made things just
-# slightly funny for merging D1 and e$, where E4 is defined as:
+# slightly funny for merging D1 and E4, where E4 is defined as:
 #   Commit E4: Merge B & C, modifying 'a' and renaming to 'a2', and deleting 'a/'
 # in this case, we'll get a rename/rename(1to2) conflict because a~$UNIQUE
 # gets renamed to 'a' in D1 and to 'a2' in E4.  But that's better than having
@@ -1144,7 +1144,7 @@
 		test_must_fail git merge -s recursive E^0 &&
 
 		git ls-files -s >out &&
-		test_line_count = 2 out &&
+		test_line_count = 3 out &&
 		git ls-files -u >out &&
 		test_line_count = 2 out &&
 		git ls-files -o >out &&
diff --git a/t/t6037-merge-ours-theirs.sh b/t/t6417-merge-ours-theirs.sh
similarity index 100%
rename from t/t6037-merge-ours-theirs.sh
rename to t/t6417-merge-ours-theirs.sh
diff --git a/t/t6038-merge-text-auto.sh b/t/t6418-merge-text-auto.sh
similarity index 98%
rename from t/t6038-merge-text-auto.sh
rename to t/t6418-merge-text-auto.sh
index 89c86d4..30983d1 100755
--- a/t/t6038-merge-text-auto.sh
+++ b/t/t6418-merge-text-auto.sh
@@ -197,7 +197,8 @@
 	git commit -m "remove file" &&
 	git checkout master &&
 	git reset --hard a^ &&
-	git merge side
+	git merge side &&
+	test_path_is_missing file
 '
 
 test_done
diff --git a/t/t6039-merge-ignorecase.sh b/t/t6419-merge-ignorecase.sh
similarity index 100%
rename from t/t6039-merge-ignorecase.sh
rename to t/t6419-merge-ignorecase.sh
diff --git a/t/t6042-merge-rename-corner-cases.sh b/t/t6422-merge-rename-corner-cases.sh
similarity index 94%
rename from t/t6042-merge-rename-corner-cases.sh
rename to t/t6422-merge-rename-corner-cases.sh
index f163893..3375eaf 100755
--- a/t/t6042-merge-rename-corner-cases.sh
+++ b/t/t6422-merge-rename-corner-cases.sh
@@ -457,7 +457,7 @@
 		git checkout A^0 &&
 
 		test_must_fail git merge -s recursive B^0 >out &&
-		test_i18ngrep "CONFLICT (rename/add)" out &&
+		test_i18ngrep "CONFLICT (.*/add)" out &&
 
 		git ls-files -s >out &&
 		test_line_count = 2 out &&
@@ -503,7 +503,7 @@
 		git checkout B^0 &&
 
 		test_must_fail git merge -s recursive A^0 >out &&
-		test_i18ngrep "CONFLICT (rename/add)" out &&
+		test_i18ngrep "CONFLICT (.*/add)" out &&
 
 		git ls-files -s >out &&
 		test_line_count = 2 out &&
@@ -583,7 +583,7 @@
 		git checkout B^0 &&
 
 		test_must_fail git merge -s recursive C^0 >out &&
-		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		test_i18ngrep "CONFLICT (\(.*\)/\1)" out &&
 
 		git ls-files -s >out &&
 		test_line_count = 2 out &&
@@ -886,12 +886,17 @@
 		git checkout B^0 &&
 		test_must_fail git merge -s recursive A^0 >out 2>err &&
 
-		# Not sure whether the output should contain just one
-		# "CONFLICT (rename/add/delete)" line, or if it should break
-		# it into a pair of "CONFLICT (rename/delete)" and
-		# "CONFLICT (rename/add)"; allow for either.
-		test_i18ngrep "CONFLICT (rename.*add)" out &&
-		test_i18ngrep "CONFLICT (rename.*delete)" out &&
+		# Instead of requiring the output to contain one combined line
+		#   CONFLICT (rename/add/delete)
+		# or perhaps two lines:
+		#   CONFLICT (rename/add): new file collides with rename target
+		#   CONFLICT (rename/delete): rename source removed on other side
+		# and instead of requiring "rename/add" instead of "add/add",
+		# be flexible in the type of console output message(s) reported
+		# for this particular case; we will be more stringent about the
+		# contents of the index and working directory.
+		test_i18ngrep "CONFLICT (.*/add)" out &&
+		test_i18ngrep "CONFLICT (rename.*/delete)" out &&
 		test_must_be_empty err &&
 
 		git ls-files -s >file_count &&
@@ -899,14 +904,14 @@
 		git ls-files -u >file_count &&
 		test_line_count = 2 file_count &&
 		git ls-files -o >file_count &&
-		test_line_count = 2 file_count &&
+		test_line_count = 3 file_count &&
 
 		git rev-parse >actual \
 			:2:bar :3:bar &&
 		git rev-parse >expect \
 			B:bar  A:bar  &&
 
-		test_cmp file_is_missing foo &&
+		test_path_is_missing foo &&
 		# bar should have two-way merged contents of the different
 		# versions of bar; check that content from both sides is
 		# present.
@@ -954,11 +959,17 @@
 		git checkout A^0 &&
 		test_must_fail git merge -s recursive B^0 >out 2>err &&
 
-		# Not sure whether the output should contain just one
-		# "CONFLICT (rename/rename/delete/delete)" line, or if it
-		# should break it into three: "CONFLICT (rename/rename)" and
-		# two "CONFLICT (rename/delete)" lines; allow for either.
-		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		# Instead of requiring the output to contain one combined line
+		#   CONFLICT (rename/rename/delete/delete)
+		# or perhaps two lines:
+		#   CONFLICT (rename/rename): ...
+		#   CONFLICT (rename/delete): info about pair 1
+		#   CONFLICT (rename/delete): info about pair 2
+		# and instead of requiring "rename/rename" instead of "add/add",
+		# be flexible in the type of console output message(s) reported
+		# for this particular case; we will be more stringent about the
+		# contents of the index and working directory.
+		test_i18ngrep "CONFLICT (\(.*\)/\1)" out &&
 		test_i18ngrep "CONFLICT (rename.*delete)" out &&
 		test_must_be_empty err &&
 
@@ -967,15 +978,15 @@
 		git ls-files -u >file_count &&
 		test_line_count = 2 file_count &&
 		git ls-files -o >file_count &&
-		test_line_count = 2 file_count &&
+		test_line_count = 3 file_count &&
 
 		git rev-parse >actual \
 			:2:baz :3:baz &&
 		git rev-parse >expect \
 			O:foo  O:bar  &&
 
-		test_cmp file_is_missing foo &&
-		test_cmp file_is_missing bar &&
+		test_path_is_missing foo &&
+		test_path_is_missing bar &&
 		# baz should have two-way merged contents of the original
 		# contents of foo and bar; check that content from both sides
 		# is present.
@@ -1042,25 +1053,25 @@
 		test_must_be_empty err &&
 
 		git ls-files -s >file_count &&
-		test_line_count = 6 file_count &&
+		test_line_count = 9 file_count &&
 		git ls-files -u >file_count &&
-		test_line_count = 6 file_count &&
+		test_line_count = 9 file_count &&
 		git ls-files -o >file_count &&
 		test_line_count = 3 file_count &&
 
 		test_seq 10 20 >merged-one &&
 		test_seq 51 60 >merged-five &&
 		# Determine what the merge of three would give us.
-		test_seq 30 40 >three-side-A &&
+		test_seq 31 39 >three-base &&
+		test_seq 31 40 >three-side-A &&
 		test_seq 31 39 >three-side-B &&
-		echo forty >three-side-B &&
-		>empty &&
+		echo forty >>three-side-B &&
 		test_must_fail git merge-file \
-			-L "HEAD" \
+			-L "HEAD:four" \
 			-L "" \
-			-L "B^0" \
-			three-side-A empty three-side-B &&
-		sed -e "s/^\([<=>]\)/\1\1\1/" three-side-A >merged-three &&
+			-L "B^0:two" \
+			three-side-A three-base three-side-B &&
+		sed -e "s/^\([<=>]\)/\1\1/" three-side-A >merged-three &&
 
 		# Verify the index is as expected
 		git rev-parse >actual         \
@@ -1075,6 +1086,7 @@
 
 		git cat-file -p :2:two >expect &&
 		git cat-file -p :3:two >other &&
+		>empty &&
 		test_must_fail git merge-file    \
 			-L "HEAD"  -L ""  -L "B^0" \
 			expect     empty  other &&
diff --git a/t/t6043-merge-rename-directories.sh b/t/t6423-merge-rename-directories.sh
similarity index 98%
rename from t/t6043-merge-rename-directories.sh
rename to t/t6423-merge-rename-directories.sh
index 83792c5..f7ecbb8 100755
--- a/t/t6043-merge-rename-directories.sh
+++ b/t/t6423-merge-rename-directories.sh
@@ -275,7 +275,7 @@
 		git checkout A^0 &&
 
 		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
-		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		test_i18ngrep "CONFLICT (\(.*\)/\1)" out &&
 
 		git ls-files -s >out &&
 		test_line_count = 8 out &&
@@ -1686,7 +1686,7 @@
 		git checkout A^0 &&
 
 		test_must_fail git -c merge.directoryRenames=true merge -s recursive B^0 >out &&
-		test_i18ngrep "CONFLICT (rename/rename)" out &&
+		test_i18ngrep "CONFLICT (\(.*\)/\1)" out &&
 
 		git ls-files -s >out &&
 		test_line_count = 4 out &&
@@ -2260,24 +2260,23 @@
 #   Commit B: w/{b,c}, z/d
 #
 # Possible Resolutions:
-#   w/o dir-rename detection: z/d, CONFLICT(z/b -> y/b vs. w/b),
-#                                  CONFLICT(z/c -> y/c vs. w/c)
-#   Currently expected:       y/d, CONFLICT(z/b -> y/b vs. w/b),
-#                                  CONFLICT(z/c -> y/c vs. w/c)
-#   Optimal:                  ??
+#   if z not considered renamed: z/d, CONFLICT(z/b -> y/b vs. w/b),
+#                                     CONFLICT(z/c -> y/c vs. w/c)
+#   if z->y rename considered:   y/d, CONFLICT(z/b -> y/b vs. w/b),
+#                                     CONFLICT(z/c -> y/c vs. w/c)
+#   Optimal:                     ??
 #
 # Notes: In commit A, directory z got renamed to y.  In commit B, directory z
 #        did NOT get renamed; the directory is still present; instead it is
 #        considered to have just renamed a subset of paths in directory z
-#        elsewhere.  Therefore, the directory rename done in commit A to z/
-#        applies to z/d and maps it to y/d.
+#        elsewhere.  However, this is much like testcase 6b (where commit B
+#        moves all the original paths out of z/ but opted to keep d
+#        within z/).  This makes it hard to judge where d should end up.
 #
 #        It's possible that users would get confused about this, but what
-#        should we do instead?  Silently leaving at z/d seems just as bad or
-#        maybe even worse.  Perhaps we could print a big warning about z/d
-#        and how we're moving to y/d in this case, but when I started thinking
-#        about the ramifications of doing that, I didn't know how to rule out
-#        that opening other weird edge and corner cases so I just punted.
+#        should we do instead?  It's not at all clear to me whether z/d or
+#        y/d or something else is a better resolution here, and other cases
+#        start getting really tricky, so I just picked one.
 
 test_setup_8e () {
 	test_create_repo 8e &&
@@ -2844,6 +2843,14 @@
 #   Commit A: priority/{alpha,bravo}/$more_files
 #   Commit B: goal/{a,b}/$more_files, goal/c
 #   Expected: priority/{alpha,bravo}/$more_files, priority/c
+# We currently fail this test because the directory renames we detect are
+#   goal/a/ -> priority/alpha/
+#   goal/b/ -> priority/bravo/
+# We do not detect
+#   goal/   -> priority/
+# because of no files found within goal/, and the fact that "a" != "alpha"
+# and "b" != "bravo".  But I'm not sure it's really a failure given that
+# viewpoint...
 
 test_setup_9g () {
 	test_create_repo 9g &&
@@ -2880,6 +2887,7 @@
 }
 
 test_expect_failure '9g: Renamed directory that only contained immediate subdirs, immediate subdirs renamed' '
+	test_setup_9g &&
 	(
 		cd 9g &&
 
@@ -3362,6 +3370,7 @@
 }
 
 test_expect_failure '10e: Does git complain about untracked file that is not really in the way?' '
+	test_setup_10e &&
 	(
 		cd 10e &&
 
@@ -4403,7 +4412,7 @@
 #   Commit O: z/{b,c},   x/{d,e}
 #   Commit A: y/{b,c,d}, x/e
 #   Commit B: z/{b,c,d}, x/e
-#   Expected: y/{b,c,d}, with info or conflict messages for d (
+#   Expected: y/{b,c,d}, x/e, with info or conflict messages for d
 #             A: renamed x/d -> z/d; B: renamed z/ -> y/ AND renamed x/d to y/d
 #             One could argue A had partial knowledge of what was done with
 #             d and B had full knowledge, but that's a slippery slope as
diff --git a/t/t6044-merge-unrelated-index-changes.sh b/t/t6424-merge-unrelated-index-changes.sh
similarity index 100%
rename from t/t6044-merge-unrelated-index-changes.sh
rename to t/t6424-merge-unrelated-index-changes.sh
diff --git a/t/t6045-merge-rename-delete.sh b/t/t6425-merge-rename-delete.sh
similarity index 72%
rename from t/t6045-merge-rename-delete.sh
rename to t/t6425-merge-rename-delete.sh
index 5d33577..f79d021 100755
--- a/t/t6045-merge-rename-delete.sh
+++ b/t/t6425-merge-rename-delete.sh
@@ -17,7 +17,8 @@
 	git commit -m "delete" &&
 
 	test_must_fail git merge --strategy=recursive rename >output &&
-	test_i18ngrep "CONFLICT (rename/delete): A deleted in HEAD and renamed to B in rename. Version rename of B left in tree." output
+	test_i18ngrep "CONFLICT (rename/delete): A.* renamed .*to B.* in rename" output &&
+	test_i18ngrep "CONFLICT (rename/delete): A.*deleted in HEAD." output
 '
 
 test_done
diff --git a/t/t6046-merge-skip-unneeded-updates.sh b/t/t6426-merge-skip-unneeded-updates.sh
similarity index 99%
rename from t/t6046-merge-skip-unneeded-updates.sh
rename to t/t6426-merge-skip-unneeded-updates.sh
index 5a2d07e..6998136 100755
--- a/t/t6046-merge-skip-unneeded-updates.sh
+++ b/t/t6426-merge-skip-unneeded-updates.sh
@@ -374,7 +374,7 @@
 		export GIT_MERGE_VERBOSITY &&
 		test_must_fail git merge -s recursive B^0 >out 2>err &&
 
-		test_i18ngrep "CONFLICT (rename/add): Rename b->c" out &&
+		test_i18ngrep "CONFLICT (.*/add):" out &&
 		test_must_be_empty err &&
 
 		# Make sure c WAS updated
diff --git a/t/t6047-diff3-conflict-markers.sh b/t/t6427-diff3-conflict-markers.sh
similarity index 100%
rename from t/t6047-diff3-conflict-markers.sh
rename to t/t6427-diff3-conflict-markers.sh
diff --git a/t/t3030-merge-recursive.sh b/t/t6430-merge-recursive.sh
similarity index 100%
rename from t/t3030-merge-recursive.sh
rename to t/t6430-merge-recursive.sh
diff --git a/t/t3031-merge-criscross.sh b/t/t6431-merge-criscross.sh
similarity index 100%
rename from t/t3031-merge-criscross.sh
rename to t/t6431-merge-criscross.sh
diff --git a/t/t3032-merge-recursive-space-options.sh b/t/t6432-merge-recursive-space-options.sh
similarity index 100%
rename from t/t3032-merge-recursive-space-options.sh
rename to t/t6432-merge-recursive-space-options.sh
diff --git a/t/t3033-merge-toplevel.sh b/t/t6433-merge-toplevel.sh
similarity index 100%
rename from t/t3033-merge-toplevel.sh
rename to t/t6433-merge-toplevel.sh
diff --git a/t/t3034-merge-recursive-rename-options.sh b/t/t6434-merge-recursive-rename-options.sh
similarity index 100%
rename from t/t3034-merge-recursive-rename-options.sh
rename to t/t6434-merge-recursive-rename-options.sh
diff --git a/t/t3035-merge-sparse.sh b/t/t6435-merge-sparse.sh
similarity index 100%
rename from t/t3035-merge-sparse.sh
rename to t/t6435-merge-sparse.sh
diff --git a/t/t7607-merge-overwrite.sh b/t/t6436-merge-overwrite.sh
similarity index 100%
rename from t/t7607-merge-overwrite.sh
rename to t/t6436-merge-overwrite.sh
diff --git a/t/t7405-submodule-merge.sh b/t/t6437-submodule-merge.sh
similarity index 100%
rename from t/t7405-submodule-merge.sh
rename to t/t6437-submodule-merge.sh
diff --git a/t/t7613-merge-submodule.sh b/t/t6438-submodule-directory-file-conflicts.sh
similarity index 100%
rename from t/t7613-merge-submodule.sh
rename to t/t6438-submodule-directory-file-conflicts.sh
diff --git a/t/t7609-merge-co-error-msgs.sh b/t/t6439-merge-co-error-msgs.sh
similarity index 100%
rename from t/t7609-merge-co-error-msgs.sh
rename to t/t6439-merge-co-error-msgs.sh
diff --git a/t/t7401-submodule-summary.sh b/t/t7401-submodule-summary.sh
index 9bc841d..cc87d26 100755
--- a/t/t7401-submodule-summary.sh
+++ b/t/t7401-submodule-summary.sh
@@ -5,8 +5,11 @@
 
 test_description='Summary support for submodules
 
-This test tries to verify the sanity of summary subcommand of git submodule.
+This test script tries to verify the sanity of summary subcommand of git submodule.
 '
+# NEEDSWORK: This test script is old fashioned and may need a big cleanup due to
+# various reasons, one of them being that there are lots of commands taking place
+# outside of 'test_expect_success' block, which is no longer in good-style.
 
 . ./test-lib.sh
 
@@ -16,12 +19,12 @@
 	owd=$(pwd)
 	cd "$sm"
 	for name; do
-		echo "$name" > "$name" &&
+		echo "$name" >"$name" &&
 		git add "$name" &&
 		test_tick &&
 		git commit -m "Add $name"
 	done >/dev/null
-	git rev-parse --verify HEAD | cut -c1-7
+	git rev-parse --short HEAD
 	cd "$owd"
 }
 commit_file () {
@@ -38,10 +41,10 @@
 	git add sm1 &&
 	git submodule summary >actual &&
 	cat >expected <<-EOF &&
-* sm1 0000000...$head1 (2):
-  > Add foo2
+	* sm1 0000000...$head1 (2):
+	  > Add foo2
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
@@ -52,10 +55,10 @@
 		git submodule summary >../actual
 	) &&
 	cat >expected <<-EOF &&
-* ../sm1 0000000...$head1 (2):
-  > Add foo2
+	* ../sm1 0000000...$head1 (2):
+	  > Add foo2
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
@@ -73,10 +76,10 @@
 		git submodule summary ../sm1 >../actual
 	) &&
 	cat >expected <<-EOF &&
-* ../sm1 0000000...$head1 (2):
-  > Add foo2
+	* ../sm1 0000000...$head1 (2):
+	  > Add foo2
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
@@ -86,20 +89,20 @@
 test_expect_success 'modified submodule(forward)' "
 	git submodule summary >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head1...$head2 (1):
-  > Add foo3
+	* sm1 $head1...$head2 (1):
+	  > Add foo3
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
 test_expect_success 'modified submodule(forward), --files' "
 	git submodule summary --files >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head1...$head2 (1):
-  > Add foo3
+	* sm1 $head1...$head2 (1):
+	  > Add foo3
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
@@ -110,10 +113,10 @@
 	git config diff.ignoreSubmodules all &&
 	git submodule summary >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head1...$head2 (1):
-  > Add foo3
+	* sm1 $head1...$head2 (1):
+	  > Add foo3
 
-EOF
+	EOF
 	test_cmp expected actual &&
 	git config --unset diff.ignoreSubmodules &&
 	git config --remove-section submodule.sm1 &&
@@ -125,17 +128,17 @@
 head3=$(
 	cd sm1 &&
 	git reset --hard HEAD~2 >/dev/null &&
-	git rev-parse --verify HEAD | cut -c1-7
+	git rev-parse --short HEAD
 )
 
 test_expect_success 'modified submodule(backward)' "
 	git submodule summary >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head2...$head3 (2):
-  < Add foo3
-  < Add foo2
+	* sm1 $head2...$head3 (2):
+	  < Add foo3
+	  < Add foo2
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
@@ -144,25 +147,25 @@
 test_expect_success 'modified submodule(backward and forward)' "
 	git submodule summary >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head2...$head4 (4):
-  > Add foo5
-  > Add foo4
-  < Add foo3
-  < Add foo2
+	* sm1 $head2...$head4 (4):
+	  > Add foo5
+	  > Add foo4
+	  < Add foo3
+	  < Add foo2
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
 test_expect_success '--summary-limit' "
 	git submodule summary -n 3 >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head2...$head4 (4):
-  > Add foo5
-  > Add foo4
-  < Add foo3
+	* sm1 $head2...$head4 (4):
+	  > Add foo5
+	  > Add foo4
+	  < Add foo3
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
@@ -177,21 +180,21 @@
 test_expect_success 'typechanged submodule(submodule->blob), --cached' "
 	git submodule summary --cached >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head4(submodule)->$head5(blob) (3):
-  < Add foo5
+	* sm1 $head4(submodule)->$head5(blob) (3):
+	  < Add foo5
 
-EOF
-	test_i18ncmp actual expected
+	EOF
+	test_i18ncmp expected actual
 "
 
 test_expect_success 'typechanged submodule(submodule->blob), --files' "
 	git submodule summary --files >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head5(blob)->$head4(submodule) (3):
-  > Add foo5
+	* sm1 $head5(blob)->$head4(submodule) (3):
+	  > Add foo5
 
-EOF
-	test_i18ncmp actual expected
+	EOF
+	test_i18ncmp expected actual
 "
 
 rm -rf sm1 &&
@@ -199,10 +202,10 @@
 test_expect_success 'typechanged submodule(submodule->blob)' "
 	git submodule summary >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head4(submodule)->$head5(blob):
+	* sm1 $head4(submodule)->$head5(blob):
 
-EOF
-	test_i18ncmp actual expected
+	EOF
+	test_i18ncmp expected actual
 "
 
 rm -f sm1 &&
@@ -211,21 +214,21 @@
 test_expect_success 'nonexistent commit' "
 	git submodule summary >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head4...$head6:
-  Warn: sm1 doesn't contain commit $head4_full
+	* sm1 $head4...$head6:
+	  Warn: sm1 doesn't contain commit $head4_full
 
-EOF
-	test_i18ncmp actual expected
+	EOF
+	test_i18ncmp expected actual
 "
 
 commit_file
 test_expect_success 'typechanged submodule(blob->submodule)' "
 	git submodule summary >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head5(blob)->$head6(submodule) (2):
-  > Add foo7
+	* sm1 $head5(blob)->$head6(submodule) (2):
+	  > Add foo7
 
-EOF
+	EOF
 	test_i18ncmp expected actual
 "
 
@@ -234,9 +237,9 @@
 test_expect_success 'deleted submodule' "
 	git submodule summary >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head6...0000000:
+	* sm1 $head6...0000000:
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
@@ -249,22 +252,22 @@
 test_expect_success 'multiple submodules' "
 	git submodule summary >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head6...0000000:
+	* sm1 $head6...0000000:
 
-* sm2 0000000...$head7 (2):
-  > Add foo9
+	* sm2 0000000...$head7 (2):
+	  > Add foo9
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
 test_expect_success 'path filter' "
 	git submodule summary sm2 >actual &&
 	cat >expected <<-EOF &&
-* sm2 0000000...$head7 (2):
-  > Add foo9
+	* sm2 0000000...$head7 (2):
+	  > Add foo9
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
@@ -272,24 +275,24 @@
 test_expect_success 'given commit' "
 	git submodule summary HEAD^ >actual &&
 	cat >expected <<-EOF &&
-* sm1 $head6...0000000:
+	* sm1 $head6...0000000:
 
-* sm2 0000000...$head7 (2):
-  > Add foo9
+	* sm2 0000000...$head7 (2):
+	  > Add foo9
 
-EOF
+	EOF
 	test_cmp expected actual
 "
 
 test_expect_success '--for-status' "
 	git submodule summary --for-status HEAD^ >actual &&
-	test_i18ncmp actual - <<EOF
-* sm1 $head6...0000000:
+	test_i18ncmp - actual <<-EOF
+	* sm1 $head6...0000000:
 
-* sm2 0000000...$head7 (2):
-  > Add foo9
+	* sm2 0000000...$head7 (2):
+	  > Add foo9
 
-EOF
+	EOF
 "
 
 test_expect_success 'fail when using --files together with --cached' "
diff --git a/t/t7518-ident-corner-cases.sh b/t/t7518-ident-corner-cases.sh
index b22f631..dc3e9c8 100755
--- a/t/t7518-ident-corner-cases.sh
+++ b/t/t7518-ident-corner-cases.sh
@@ -29,7 +29,18 @@
 		sane_unset GIT_AUTHOR_NAME &&
 		test_must_fail \
 			git -c user.name= commit --allow-empty -m foo 2>err &&
-		test_i18ngrep "empty ident name" err
+		test_i18ngrep "empty ident name" err &&
+		test_i18ngrep "Author identity unknown" err
+	)
+'
+
+test_expect_success 'empty configured name does not auto-detect for committer' '
+	(
+		sane_unset GIT_COMMITTER_NAME &&
+		test_must_fail \
+			git -c user.name= commit --allow-empty -m foo 2>err &&
+		test_i18ngrep "empty ident name" err &&
+		test_i18ngrep "Committer identity unknown" err
 	)
 '
 
diff --git a/t/t8003-blame-corner-cases.sh b/t/t8003-blame-corner-cases.sh
index b871dd4..ba8013b 100755
--- a/t/t8003-blame-corner-cases.sh
+++ b/t/t8003-blame-corner-cases.sh
@@ -273,18 +273,14 @@
 	grep "A U Thor" actual
 '
 
-# Tests the splitting and merging of blame entries in blame_coalesce().
-# The output of blame is the same, regardless of whether blame_coalesce() runs
-# or not, so we'd likely only notice a problem if blame crashes or assigned
-# blame to the "splitting" commit ('SPLIT' below).
-test_expect_success 'blame coalesce' '
+test_expect_success 'setup coalesce tests' '
 	cat >giraffe <<-\EOF &&
 	ABC
 	DEF
 	EOF
 	git add giraffe &&
 	git commit -m "original file" &&
-	oid=$(git rev-parse HEAD) &&
+	orig=$(git rev-parse HEAD) &&
 
 	cat >giraffe <<-\EOF &&
 	ABC
@@ -293,6 +289,7 @@
 	EOF
 	git add giraffe &&
 	git commit -m "interior SPLIT line" &&
+	split=$(git rev-parse HEAD) &&
 
 	cat >giraffe <<-\EOF &&
 	ABC
@@ -300,12 +297,25 @@
 	EOF
 	git add giraffe &&
 	git commit -m "same contents as original" &&
+	final=$(git rev-parse HEAD)
+'
 
+test_expect_success 'blame coalesce' '
 	cat >expect <<-EOF &&
-	$oid 1) ABC
-	$oid 2) DEF
+	$orig 1 1 2
+	$orig 2 2
 	EOF
-	git -c core.abbrev=$(test_oid hexsz) blame -s giraffe >actual &&
+	git blame --porcelain $final giraffe >actual.raw &&
+	grep "^$orig" actual.raw >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'blame does not coalesce non-adjacent result lines' '
+	cat >expect <<-EOF &&
+	$orig 1) ABC
+	$orig 3) DEF
+	EOF
+	git blame --no-abbrev -s -L1,1 -L3,3 $split giraffe >actual &&
 	test_cmp expect actual
 '
 
diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh
index 3d68570..a08f725 100755
--- a/t/t9001-send-email.sh
+++ b/t/t9001-send-email.sh
@@ -2142,4 +2142,33 @@
 		"$(pwd)/0001-add-master.patch"
 '
 
+test_expect_success $PREREQ 'test that sendmail config is rejected' '
+	test_config sendmail.program sendmail &&
+	test_must_fail git send-email \
+		--from="Example <nobody@example.com>" \
+		--to=nobody@example.com \
+		--smtp-server="$(pwd)/fake.sendmail" \
+		HEAD^ 2>err &&
+	test_i18ngrep "found configuration options for '"'"sendmail"'"'" err
+'
+
+test_expect_success $PREREQ 'test that sendmail config rejection is specific' '
+	test_config resendmail.program sendmail &&
+	git send-email \
+		--from="Example <nobody@example.com>" \
+		--to=nobody@example.com \
+		--smtp-server="$(pwd)/fake.sendmail" \
+		HEAD^
+'
+
+test_expect_success $PREREQ 'test forbidSendmailVariables behavior override' '
+	test_config sendmail.program sendmail &&
+	test_config sendemail.forbidSendmailVariables false &&
+	git send-email \
+		--from="Example <nobody@example.com>" \
+		--to=nobody@example.com \
+		--smtp-server="$(pwd)/fake.sendmail" \
+		HEAD^
+'
+
 test_done
diff --git a/t/test-lib-functions.sh b/t/test-lib-functions.sh
index 596c549..6a8e194 100644
--- a/t/test-lib-functions.sh
+++ b/t/test-lib-functions.sh
@@ -952,7 +952,13 @@
 # - not all diff versions understand "-u"
 
 test_cmp() {
-	eval "$GIT_TEST_CMP" '"$@"'
+	test $# -eq 2 || BUG "test_cmp requires two arguments"
+	if ! eval "$GIT_TEST_CMP" '"$@"'
+	then
+		test "x$1" = x- || test -e "$1" || BUG "test_cmp '$1' missing"
+		test "x$2" = x- || test -e "$2" || BUG "test_cmp '$2' missing"
+		return 1
+	fi
 }
 
 # Check that the given config key has the expected value.
@@ -981,7 +987,13 @@
 # test_cmp_bin - helper to compare binary files
 
 test_cmp_bin() {
-	cmp "$@"
+	test $# -eq 2 || BUG "test_cmp_bin requires two arguments"
+	if ! cmp "$@"
+	then
+		test "x$1" = x- || test -e "$1" || BUG "test_cmp_bin '$1' missing"
+		test "x$2" = x- || test -e "$2" || BUG "test_cmp_bin '$2' missing"
+		return 1
+	fi
 }
 
 # Use this instead of test_cmp to compare files that contain expected and
diff --git a/transport.c b/transport.c
index 2d4fd85..419be0b 100644
--- a/transport.c
+++ b/transport.c
@@ -443,6 +443,7 @@
 	if (ref->status != REF_STATUS_OK && ref->status != REF_STATUS_UPTODATE)
 		return;
 
+	memset(&rs, 0, sizeof(rs));
 	rs.src = ref->name;
 	rs.dst = NULL;
 
diff --git a/upload-pack.c b/upload-pack.c
index 80ad9a3..3b858eb 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -603,9 +603,8 @@
 		"rev-list", "--stdin", NULL,
 	};
 	struct object *o;
-	char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
+	FILE *cmd_in = NULL;
 	int i;
-	const unsigned hexsz = the_hash_algo->hexsz;
 
 	cmd->argv = argv;
 	cmd->git_cmd = 1;
@@ -623,8 +622,8 @@
 	if (start_command(cmd))
 		goto error;
 
-	namebuf[0] = '^';
-	namebuf[hexsz + 1] = '\n';
+	cmd_in = xfdopen(cmd->in, "w");
+
 	for (i = get_max_object_index(); 0 < i; ) {
 		o = get_indexed_object(--i);
 		if (!o)
@@ -633,11 +632,9 @@
 			o->flags &= ~TMP_MARK;
 		if (!is_our_ref(o, allow_uor))
 			continue;
-		memcpy(namebuf + 1, oid_to_hex(&o->oid), hexsz);
-		if (write_in_full(cmd->in, namebuf, hexsz + 2) < 0)
+		if (fprintf(cmd_in, "^%s\n", oid_to_hex(&o->oid)) < 0)
 			goto error;
 	}
-	namebuf[hexsz] = '\n';
 	for (i = 0; i < src->nr; i++) {
 		o = src->objects[i].item;
 		if (is_our_ref(o, allow_uor)) {
@@ -647,11 +644,12 @@
 		}
 		if (reachable && o->type == OBJ_COMMIT)
 			o->flags |= TMP_MARK;
-		memcpy(namebuf, oid_to_hex(&o->oid), hexsz);
-		if (write_in_full(cmd->in, namebuf, hexsz + 1) < 0)
+		if (fprintf(cmd_in, "%s\n", oid_to_hex(&o->oid)) < 0)
 			goto error;
 	}
-	close(cmd->in);
+	if (ferror(cmd_in) || fflush(cmd_in))
+		goto error;
+	fclose(cmd_in);
 	cmd->in = -1;
 	sigchain_pop(SIGPIPE);
 
@@ -660,8 +658,8 @@
 error:
 	sigchain_pop(SIGPIPE);
 
-	if (cmd->in >= 0)
-		close(cmd->in);
+	if (cmd_in)
+		fclose(cmd_in);
 	if (cmd->out >= 0)
 		close(cmd->out);
 	return -1;
@@ -739,7 +737,6 @@
 	return 0;
 
 error:
-	sigchain_pop(SIGPIPE);
 	if (cmd.out >= 0)
 		close(cmd.out);
 	return 1;
diff --git a/userdiff.c b/userdiff.c
index 1df884e..fde02f2 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -46,10 +46,14 @@
 	 /* Not real operators, but should be grouped */
 	 "|:?%[A-Za-z0-9_.]\\{\\}?"),
 IPATTERN("fortran",
+	 /* Don't match comment lines */
 	 "!^([C*]|[ \t]*!)\n"
+	 /* Don't match 'module procedure' lines */
 	 "!^[ \t]*MODULE[ \t]+PROCEDURE[ \t]\n"
+	 /* Program, module, block data */
 	 "^[ \t]*((END[ \t]+)?(PROGRAM|MODULE|BLOCK[ \t]+DATA"
-		"|([^'\" \t]+[ \t]+)*(SUBROUTINE|FUNCTION))[ \t]+[A-Z].*)$",
+		/* Subroutines and functions */
+		"|([^!'\" \t]+[ \t]+)*(SUBROUTINE|FUNCTION))[ \t]+[A-Z].*)$",
 	 /* -- */
 	 "[a-zA-Z][a-zA-Z0-9_]*"
 	 "|\\.([Ee][Qq]|[Nn][Ee]|[Gg][TtEe]|[Ll][TtEe]|[Tt][Rr][Uu][Ee]|[Ff][Aa][Ll][Ss][Ee]|[Aa][Nn][Dd]|[Oo][Rr]|[Nn]?[Ee][Qq][Vv]|[Nn][Oo][Tt])\\."
diff --git a/wt-status.c b/wt-status.c
index d753990..bb0f912 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -703,7 +703,7 @@
 	if (!s->show_untracked_files)
 		return;
 
-	memset(&dir, 0, sizeof(dir));
+	dir_init(&dir);
 	if (s->show_untracked_files != SHOW_ALL_UNTRACKED_FILES)
 		dir.flags |=
 			DIR_SHOW_OTHER_DIRECTORIES | DIR_HIDE_EMPTY_DIRECTORIES;
@@ -724,19 +724,15 @@
 		struct dir_entry *ent = dir.entries[i];
 		if (index_name_is_other(istate, ent->name, ent->len))
 			string_list_insert(&s->untracked, ent->name);
-		free(ent);
 	}
 
 	for (i = 0; i < dir.ignored_nr; i++) {
 		struct dir_entry *ent = dir.ignored[i];
 		if (index_name_is_other(istate, ent->name, ent->len))
 			string_list_insert(&s->ignored, ent->name);
-		free(ent);
 	}
 
-	free(dir.entries);
-	free(dir.ignored);
-	clear_directory(&dir);
+	dir_clear(&dir);
 
 	if (advice_status_u_option)
 		s->untracked_in_ms = (getnanotime() - t_begin) / 1000000;
@@ -1672,13 +1668,13 @@
 		state->merge_in_progress = 1;
 	} else if (wt_status_check_rebase(NULL, state)) {
 		;		/* all set */
-	} else if (!stat(git_path_cherry_pick_head(r), &st) &&
-			!get_oid("CHERRY_PICK_HEAD", &oid)) {
+	} else if (refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD") &&
+		   !get_oid("CHERRY_PICK_HEAD", &oid)) {
 		state->cherry_pick_in_progress = 1;
 		oidcpy(&state->cherry_pick_head_oid, &oid);
 	}
 	wt_status_check_bisect(NULL, state);
-	if (!stat(git_path_revert_head(r), &st) &&
+	if (refs_ref_exists(get_main_ref_store(r), "REVERT_HEAD") &&
 	    !get_oid("REVERT_HEAD", &oid)) {
 		state->revert_in_progress = 1;
 		oidcpy(&state->revert_head_oid, &oid);