Merge branch 'jh/builtin-fsmonitor-part2' into jh/builtin-fsmonitor-part3

* jh/builtin-fsmonitor-part2: (150 commits)
  t7527: test status with untracked-cache and fsmonitor--daemon
  fsmonitor: force update index after large responses
  fsmonitor--daemon: use a cookie file to sync with file system
  fsmonitor--daemon: periodically truncate list of modified files
  t/perf/p7519: add fsmonitor--daemon test cases
  t/perf/p7519: speed up test on Windows
  t/perf/p7519: fix coding style
  t/helper/test-chmtime: skip directories on Windows
  t/perf: avoid copying builtin fsmonitor files into test repo
  t7527: create test for fsmonitor--daemon
  t/helper/fsmonitor-client: create IPC client to talk to FSMonitor Daemon
  help: include fsmonitor--daemon feature flag in version info
  fsmonitor--daemon: implement handle_client callback
  compat/fsmonitor/fsm-listen-darwin: implement FSEvent listener on MacOS
  compat/fsmonitor/fsm-listen-darwin: add MacOS header files for FSEvent
  compat/fsmonitor/fsm-listen-win32: implement FSMonitor backend on Windows
  fsmonitor--daemon: create token-based changed path cache
  fsmonitor--daemon: define token-ids
  fsmonitor--daemon: add pathname classification
  fsmonitor--daemon: implement 'start' command
  ...

.gitignore

@@ -72,6 +72,7 @@
 /git-format-patch
 /git-fsck
 /git-fsck-objects
+/git-fsmonitor--daemon
 /git-gc
 /git-get-tar-commit-id
 /git-grep

.mailmap

@@ -59,8 +59,9 @@ David Reiss <dreiss@facebook.com> <dreiss@dreiss-vmware.(none)>
 David S. Miller <davem@davemloft.net>
 David Turner <novalis@novalis.org> <dturner@twopensource.com>
 David Turner <novalis@novalis.org> <dturner@twosigma.com>
-Derrick Stolee <dstolee@microsoft.com> <stolee@gmail.com>
-Derrick Stolee <dstolee@microsoft.com> Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
+Derrick Stolee <derrickstolee@github.com> <stolee@gmail.com>
+Derrick Stolee <derrickstolee@github.com> Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
+Derrick Stolee <derrickstolee@github.com> <dstolee@microsoft.com>
 Deskin Miller <deskinm@umich.edu>
 Đoàn Trần Công Danh <congdanhqx@gmail.com> Doan Tran Cong Danh
 Dirk Süsserott <newsletter@dirk.my1.cc>

CODE_OF_CONDUCT.md

@@ -70,8 +70,8 @@ git@sfconservancy.org, or individually:
 
   - Ævar Arnfjörð Bjarmason <avarab@gmail.com>
   - Christian Couder <christian.couder@gmail.com>
-  - Jeff King <peff@peff.net>
   - Junio C Hamano <gitster@pobox.com>
+  - Taylor Blau <me@ttaylorr.com>
 
 All complaints will be reviewed and investigated promptly and fairly.
 

Documentation/RelNotes/2.36.0.txt

@@ -9,6 +9,10 @@ Backward compatibility warts
  * "git name-rev --stdin" has been deprecated and issues a warning
    when used; use "git name-rev --annotate-stdin" instead.
 
+ * "git clone --filter=... --recurse-submodules" only makes the
+   top-level a partial clone, while submodules are fully cloned.  This
+   behaviour is changed to pass the same filter down to the submodules.
+
 
 Note to those who build from the source
 
@@ -25,6 +29,17 @@ UI, Workflows & Features
  * "git log --remerge-diff" shows the difference from mechanical merge
    result and the result that is actually recorded in a merge commit.
 
+ * "git log" and friends learned an option --exclude-first-parent-only
+   to propagate UNINTERESTING bit down only along the first-parent
+   chain, just like --first-parent option shows commits that lack the
+   UNINTERESTING bit only along the first-parent chain.
+
+ * The command line completion script (in contrib/) learned to
+   complete all Git subcommands, including the ones that are normally
+   hidden, when GIT_COMPLETION_SHOW_ALL_COMMANDS is used.
+
+ * "git branch" learned the "--recurse-submodules" option.
+
 
 Performance, Internal Implementation, Development Support etc.
 
@@ -47,6 +62,17 @@ Performance, Internal Implementation, Development Support etc.
    all.  Start the process of renaming it to "--annotate-stdin".
    (merge a2585719b3 jc/name-rev-stdin later to maint).
 
+ * "git update-index", "git checkout-index", and "git clean" are
+   taught to work better with the sparse checkout feature.
+
+ * Use an internal call to reset_head() helper function instead of
+   spawning "git checkout" in "rebase", and update code paths that are
+   involved in the change.
+
+ * Messages "ort" merge backend prepares while dealing with conflicted
+   paths were unnecessarily confusing since it did not differentiate
+   inner merges and outer merges.
+
 
 Fixes since v2.35
 -----------------
@@ -140,6 +166,72 @@ Fixes since v2.35
  * "git diff --diff-filter=aR" is now parsed correctly.
    (merge 75408ca949 js/diff-filter-negation-fix later to maint).
 
+ * When "git subtree" wants to create a merge, it used "git merge" and
+   let it be affected by end-user's "merge.ff" configuration, which
+   has been corrected.
+   (merge 9158a3564a tk/subtree-merge-not-ff-only later to maint).
+
+ * Unlike "git apply", "git patch-id" did not handle patches with
+   hunks that has only 1 line in either preimage or postimage, which
+   has been corrected.
+   (merge 757e75c81e jz/patch-id-hunk-header-parsing-fix later to maint).
+
+ * "receive-pack" checks if it will do any ref updates (various
+   conditions could reject a push) before received objects are taken
+   out of the temporary directory used for quarantine purposes, so
+   that a push that is known-to-fail will not leave crufts that a
+   future "gc" needs to clean up.
+   (merge 5407764069 cb/clear-quarantine-early-on-all-ref-update-errors later to maint).
+
+ * Because a deletion of ref would need to remove it from both the
+   loose ref store and the packed ref store, a delete-ref operation
+   that logically removes one ref may end up invoking ref-transaction
+   hook twice, which has been corrected.
+   (merge 2ed1b64ebd ps/avoid-unnecessary-hook-invocation-with-packed-refs later to maint).
+
+ * When there is no object to write .bitmap file for, "git
+   multi-pack-index" triggered an error, instead of just skipping,
+   which has been corrected.
+   (merge eb57277ba3 tb/midx-no-bitmap-for-no-objects later to maint).
+
+ * "git cmd -h" outside a repository should error out cleanly for many
+   commands, but instead it hit a BUG(), which has been corrected.
+   (merge 87ad07d735 js/short-help-outside-repo-fix later to maint).
+
+ * "working tree" and "per-worktree ref" were in glossary, but
+   "worktree" itself wasn't, which has been corrected.
+   (merge 2df5387ed0 jc/glossary-worktree later to maint).
+
+ * L10n support for a few error messages.
+   (merge 3d3c23b3a7 bs/forbid-i18n-of-protocol-token-in-fetch-pack later to maint).
+
+ * Test modernization.
+   (merge d4fe066e4b sy/t0001-use-path-is-helper later to maint).
+
+ * "git log --graph --graph" used to leak a graph structure, and there
+   was no way to countermand "--graph" that appear earlier on the
+   command line.  A "--no-graph" option has been added and resource
+   leakage has been plugged.
+
+ * Error output given in response to an ambiguous object name has been
+   improved.
+   (merge 3a73c1dfaf ab/ambiguous-object-name later to maint).
+
+ * "git sparse-checkout" wants to work with per-worktree configuration,
+   but did not work well in a worktree attached to a bare repository.
+   (merge 3ce1138272 ds/sparse-checkout-requires-per-worktree-config later to maint).
+
+ * Setting core.untrackedCache to true failed to add the untracked
+   cache extension to the index.
+
+ * Workaround we have for versions of PCRE2 before their version 10.36
+   were in effect only for their versions newer than 10.36 by mistake,
+   which has been corrected.
+   (merge 97169fc361 rs/pcre-invalid-utf8-fix-fix later to maint).
+
+ * Document Taylor as a new member of Git PLC at SFC.  Welcome.
+   (merge e8d56ca863 tb/coc-plc-update later to maint).
+
  * Other code cleanup, docfix, build fix, etc.
    (merge cfc5cf428b jc/find-header later to maint).
    (merge 40e7cfdd46 jh/p4-fix-use-of-process-error-exception later to maint).
@@ -157,3 +249,10 @@ Fixes since v2.35
    (merge 45d0212a71 ll/doc-mktree-typofix later to maint).
    (merge e9b272e4c1 js/no-more-legacy-stash later to maint).
    (merge 6798b08e84 ab/do-not-hide-failures-in-git-dot-pm later to maint).
+   (merge 9325285df4 po/doc-check-ignore-markup-fix later to maint).
+   (merge cd26cd6c7c sy/modernize-t-lib-read-tree-m-3way later to maint).
+   (merge d17294a05e ab/hash-object-leakfix later to maint).
+   (merge b8403129d3 jd/t0015-modernize later to maint).
+   (merge 332acc248d ds/mailmap later to maint).
+   (merge 04bf052eef ab/grep-patterntype later to maint).
+   (merge 6ee36364eb ab/diff-free-more later to maint).

Documentation/config/advice.txt

@@ -116,6 +116,9 @@ advice.*::
 	submoduleAlternateErrorStrategyDie::
 		Advice shown when a submodule.alternateErrorStrategy option
 		configured to "die" causes a fatal error.
+	submodulesNotUpdated::
+		Advice shown when a user runs a submodule command that fails
+		because `git submodule update --init` was not run.
 	addIgnoredFile::
 		Advice shown if a user attempts to add an ignored file to
 		the index.

Documentation/config/clone.txt

@@ -6,3 +6,8 @@ clone.defaultRemoteName::
 clone.rejectShallow::
 	Reject to clone a repository if it is a shallow one, can be overridden by
 	passing option `--reject-shallow` in command line. See linkgit:git-clone[1]
+
+clone.filterSubmodules::
+	If a partial clone filter is provided (see `--filter` in
+	linkgit:git-rev-list[1]) and `--recurse-submodules` is used, also apply
+	the filter to submodules.

Documentation/config/core.txt

@@ -62,22 +62,54 @@ core.protectNTFS::
 	Defaults to `true` on Windows, and `false` elsewhere.
 
 core.fsmonitor::
-	If set, the value of this variable is used as a command which
-	will identify all files that may have changed since the
-	requested date/time. This information is used to speed up git by
-	avoiding unnecessary processing of files that have not changed.
-	See the "fsmonitor-watchman" section of linkgit:githooks[5].
+	If set to true, enable the built-in file system monitor
+	daemon for this working directory (linkgit:git-fsmonitor--daemon[1]).
++
+Like hook-based file system monitors, the built-in file system monitor
+can speed up Git commands that need to refresh the Git index
+(e.g. `git status`) in a working directory with many files.  The
+built-in monitor eliminates the need to install and maintain an
+external third-party tool.
++
+The built-in file system monitor is currently available only on a
+limited set of supported platforms.  Currently, this includes Windows
+and MacOS.
++
+	Otherwise, this variable contains the pathname of the "fsmonitor"
+	hook command.
++
+This hook command is used to identify all files that may have changed
+since the requested date/time. This information is used to speed up
+git by avoiding unnecessary scanning of files that have not changed.
++
+See the "fsmonitor-watchman" section of linkgit:githooks[5].
++
+Note that if you concurrently use multiple versions of Git, such
+as one version on the command line and another version in an IDE
+tool, that the definition of `core.fsmonitor` was extended to
+allow boolean values in addition to hook pathnames.  Git versions
+2.35.1 and prior will not understand the boolean values and will
+consider the "true" or "false" values as hook pathnames to be
+invoked.  Git versions 2.26 thru 2.35.1 default to hook protocol
+V2 and will fall back to no fsmonitor (full scan).  Git versions
+prior to 2.26 default to hook protocol V1 and will silently
+assume there were no changes to report (no scan), so status
+commands may report incomplete results.  For this reason, it is
+best to upgrade all of your Git versions before using the built-in
+file system monitor.
 
 core.fsmonitorHookVersion::
-	Sets the version of hook that is to be used when calling fsmonitor.
-	There are currently versions 1 and 2. When this is not set,
-	version 2 will be tried first and if it fails then version 1
-	will be tried. Version 1 uses a timestamp as input to determine
-	which files have changes since that time but some monitors
-	like watchman have race conditions when used with a timestamp.
-	Version 2 uses an opaque string so that the monitor can return
-	something that can be used to determine what files have changed
-	without race conditions.
+	Sets the protocol version to be used when invoking the
+	"fsmonitor" hook.
++
+There are currently versions 1 and 2. When this is not set,
+version 2 will be tried first and if it fails then version 1
+will be tried. Version 1 uses a timestamp as input to determine
+which files have changes since that time but some monitors
+like Watchman have race conditions when used with a timestamp.
+Version 2 uses an opaque string so that the monitor can return
+something that can be used to determine what files have changed
+without race conditions.
 
 core.trustctime::
 	If false, the ctime differences between the index and the

Documentation/config/extensions.txt

@@ -6,3 +6,34 @@ extensions.objectFormat::
 Note that this setting should only be set by linkgit:git-init[1] or
 linkgit:git-clone[1].  Trying to change it after initialization will not
 work and will produce hard-to-diagnose issues.
+
+extensions.worktreeConfig::
+	If enabled, then worktrees will load config settings from the
+	`$GIT_DIR/config.worktree` file in addition to the
+	`$GIT_COMMON_DIR/config` file. Note that `$GIT_COMMON_DIR` and
+	`$GIT_DIR` are the same for the main working tree, while other
+	working trees have `$GIT_DIR` equal to
+	`$GIT_COMMON_DIR/worktrees/<id>/`. The settings in the
+	`config.worktree` file will override settings from any other
+	config files.
++
+When enabling `extensions.worktreeConfig`, you must be careful to move
+certain values from the common config file to the main working tree's
+`config.worktree` file, if present:
++
+* `core.worktree` must be moved from `$GIT_COMMON_DIR/config` to
+  `$GIT_COMMON_DIR/config.worktree`.
+* If `core.bare` is true, then it must be moved from `$GIT_COMMON_DIR/config`
+  to `$GIT_COMMON_DIR/config.worktree`.
++
+It may also be beneficial to adjust the locations of `core.sparseCheckout`
+and `core.sparseCheckoutCone` depending on your desire for customizable
+sparse-checkout settings for each worktree. By default, the `git
+sparse-checkout` builtin enables `extensions.worktreeConfig`, assigns
+these config values on a per-worktree basis, and uses the
+`$GIT_DIR/info/sparse-checkout` file to specify the sparsity for each
+worktree independently. See linkgit:git-sparse-checkout[1] for more
+details.
++
+For historical reasons, `extensions.worktreeConfig` is respected
+regardless of the `core.repositoryFormatVersion` setting.

Documentation/config/submodule.txt

@@ -59,18 +59,33 @@ submodule.active::
 
 submodule.recurse::
 	A boolean indicating if commands should enable the `--recurse-submodules`
-	option by default.
-	Applies to all commands that support this option
-	(`checkout`, `fetch`, `grep`, `pull`, `push`, `read-tree`, `reset`,
-	`restore` and `switch`) except `clone` and `ls-files`.
+	option by default. Defaults to false.
++
+When set to true, it can be deactivated via the
+`--no-recurse-submodules` option. Note that some Git commands
+lacking this option may call some of the above commands affected by
+`submodule.recurse`; for instance `git remote update` will call
+`git fetch` but does not have a `--no-recurse-submodules` option.
+For these commands a workaround is to temporarily change the
+configuration value by using `git -c submodule.recurse=0`.
++
+The following list shows the commands that accept
+`--recurse-submodules` and whether they are supported by this
+setting.
+
+* `checkout`, `fetch`, `grep`, `pull`, `push`, `read-tree`,
+`reset`, `restore` and `switch` are always supported.
+* `clone` and `ls-files` are not supported.
+* `branch` is supported only if `submodule.propagateBranches` is
+enabled
+
+submodule.propagateBranches::
+	[EXPERIMENTAL] A boolean that enables branching support when
+	using `--recurse-submodules` or `submodule.recurse=true`.
+	Enabling this will allow certain commands to accept
+	`--recurse-submodules` and certain commands that already accept
+	`--recurse-submodules` will now consider branches.
 	Defaults to false.
-	When set to true, it can be deactivated via the
-	`--no-recurse-submodules` option. Note that some Git commands
-	lacking this option may call some of the above commands affected by
-	`submodule.recurse`; for instance `git remote update` will call
-	`git fetch` but does not have a `--no-recurse-submodules` option.
-	For these commands a workaround is to temporarily change the
-	configuration value by using `git -c submodule.recurse=0`.
 
 submodule.fetchJobs::
 	Specifies how many submodules are fetched/cloned at the same time.

Documentation/git-branch.txt

@@ -16,7 +16,8 @@ SYNOPSIS
 	[--points-at <object>] [--format=<format>]
 	[(-r | --remotes) | (-a | --all)]
 	[--list] [<pattern>...]
-'git branch' [--track[=(direct|inherit)] | --no-track] [-f] <branchname> [<start-point>]
+'git branch' [--track[=(direct|inherit)] | --no-track] [-f]
+	[--recurse-submodules] <branchname> [<start-point>]
 'git branch' (--set-upstream-to=<upstream> | -u <upstream>) [<branchname>]
 'git branch' --unset-upstream [<branchname>]
 'git branch' (-m | -M) [<oldbranch>] <newbranch>
@@ -235,6 +236,22 @@ how the `branch.<name>.remote` and `branch.<name>.merge` options are used.
 	Do not set up "upstream" configuration, even if the
 	branch.autoSetupMerge configuration variable is set.
 
+--recurse-submodules::
+	THIS OPTION IS EXPERIMENTAL! Causes the current command to
+	recurse into submodules if `submodule.propagateBranches` is
+	enabled. See `submodule.propagateBranches` in
+	linkgit:git-config[1]. Currently, only branch creation is
+	supported.
++
+When used in branch creation, a new branch <branchname> will be created
+in the superproject and all of the submodules in the superproject's
+<start-point>. In submodules, the branch will point to the submodule
+commit in the superproject's <start-point> but the branch's tracking
+information will be set up based on the submodule's branches and remotes
+e.g. `git branch --recurse-submodules topic origin/main` will create the
+submodule branch "topic" that points to the submodule commit in the
+superproject's "origin/main", but tracks the submodule's "origin/main".
+
 --set-upstream::
 	As this option had confusing syntax, it is no longer supported.
 	Please use `--track` or `--set-upstream-to` instead.

Documentation/git-check-ignore.txt

@@ -33,7 +33,7 @@ OPTIONS
 	Instead of printing the paths that are excluded, for each path
 	that matches an exclude pattern, print the exclude pattern
 	together with the path.  (Matching an exclude pattern usually
-	means the path is excluded, but if the pattern begins with '!'
+	means the path is excluded, but if the pattern begins with "`!`"
 	then it is a negated pattern and matching it means the path is
 	NOT excluded.)
 +
@@ -77,7 +77,7 @@ If `--verbose` is specified, the output is a series of lines of the form:
 <pathname> is the path of a file being queried, <pattern> is the
 matching pattern, <source> is the pattern's source file, and <linenum>
 is the line number of the pattern within that source.  If the pattern
-contained a `!` prefix or `/` suffix, it will be preserved in the
+contained a "`!`" prefix or "`/`" suffix, it will be preserved in the
 output.  <source> will be an absolute path when referring to the file
 configured by `core.excludesFile`, or relative to the repository root
 when referring to `.git/info/exclude` or a per-directory exclude file.

Documentation/git-checkout-index.txt

@@ -12,6 +12,7 @@ SYNOPSIS
 'git checkout-index' [-u] [-q] [-a] [-f] [-n] [--prefix=<string>]
 		   [--stage=<number>|all]
 		   [--temp]
+		   [--ignore-skip-worktree-bits]
 		   [-z] [--stdin]
 		   [--] [<file>...]
 
@@ -37,8 +38,9 @@ OPTIONS
 
 -a::
 --all::
-	checks out all files in the index.  Cannot be used
-	together with explicit filenames.
+	checks out all files in the index except for those with the
+	skip-worktree bit set (see `--ignore-skip-worktree-bits`).
+	Cannot be used together with explicit filenames.
 
 -n::
 --no-create::
@@ -59,6 +61,10 @@ OPTIONS
 	write the content to temporary files.  The temporary name
 	associations will be written to stdout.
 
+--ignore-skip-worktree-bits::
+	Check out all files, including those with the skip-worktree bit
+	set.
+
 --stdin::
 	Instead of taking list of paths from the command line,
 	read list of paths from the standard input.  Paths are

Documentation/git-clone.txt

@@ -16,7 +16,7 @@ SYNOPSIS
 	  [--depth <depth>] [--[no-]single-branch] [--no-tags]
 	  [--recurse-submodules[=<pathspec>]] [--[no-]shallow-submodules]
 	  [--[no-]remote-submodules] [--jobs <n>] [--sparse] [--[no-]reject-shallow]
-	  [--filter=<filter>] [--] <repository>
+	  [--filter=<filter> [--also-filter-submodules]] [--] <repository>
 	  [<directory>]
 
 DESCRIPTION
@@ -182,6 +182,11 @@ objects from the source repository into a pack in the cloned repository.
 	at least `<size>`. For more details on filter specifications, see
 	the `--filter` option in linkgit:git-rev-list[1].
 
+--also-filter-submodules::
+	Also apply the partial clone filter to any submodules in the repository.
+	Requires `--filter` and `--recurse-submodules`. This can be turned on by
+	default by setting the `clone.filterSubmodules` config option.
+
 --mirror::
 	Set up a mirror of the source repository.  This implies `--bare`.
 	Compared to `--bare`, `--mirror` not only maps local branches of the

Documentation/git-config.txt

@@ -141,9 +141,13 @@ from all available files.
 See also <<FILES>>.
 
 --worktree::
-	Similar to `--local` except that `.git/config.worktree` is
+	Similar to `--local` except that `$GIT_DIR/config.worktree` is
 	read from or written to if `extensions.worktreeConfig` is
-	present. If not it's the same as `--local`.
+	enabled. If not it's the same as `--local`. Note that `$GIT_DIR`
+	is equal to `$GIT_COMMON_DIR` for the main working tree, but is of
+	the form `$GIT_DIR/worktrees/<id>/` for other working trees. See
+	linkgit:git-worktree[1] to learn how to enable
+	`extensions.worktreeConfig`.
 
 -f <config-file>::
 --file <config-file>::

Documentation/git-fsmonitor--daemon.txt

@@ -0,0 +1,75 @@
+git-fsmonitor--daemon(1)
+========================
+
+NAME
+----
+git-fsmonitor--daemon - A Built-in File System Monitor
+
+SYNOPSIS
+--------
+[verse]
+'git fsmonitor--daemon' start
+'git fsmonitor--daemon' run
+'git fsmonitor--daemon' stop
+'git fsmonitor--daemon' status
+
+DESCRIPTION
+-----------
+
+A daemon to watch the working directory for file and directory
+changes using platform-specific file system notification facilities.
+
+This daemon communicates directly with commands like `git status`
+using the link:technical/api-simple-ipc.html[simple IPC] interface
+instead of the slower linkgit:githooks[5] interface.
+
+This daemon is built into Git so that no third-party tools are
+required.
+
+OPTIONS
+-------
+
+start::
+	Starts a daemon in the background.
+
+run::
+	Runs a daemon in the foreground.
+
+stop::
+	Stops the daemon running in the current working
+	directory, if present.
+
+status::
+	Exits with zero status if a daemon is watching the
+	current working directory.
+
+REMARKS
+-------
+
+This daemon is a long running process used to watch a single working
+directory and maintain a list of the recently changed files and
+directories.  Performance of commands such as `git status` can be
+increased if they just ask for a summary of changes to the working
+directory and can avoid scanning the disk.
+
+When `core.fsmonitor` is set to `true` (see linkgit:git-config[1])
+commands, such as `git status`, will ask the daemon for changes and
+automatically start it (if necessary).
+
+For more information see the "File System Monitor" section in
+linkgit:git-update-index[1].
+
+CAVEATS
+-------
+
+The fsmonitor daemon does not currently know about submodules and does
+not know to filter out file system events that happen within a
+submodule.  If fsmonitor daemon is watching a super repo and a file is
+modified within the working directory of a submodule, it will report
+the change (as happening against the super repo).  However, the client
+will properly ignore these extra events, so performance may be affected
+but it will not cause an incorrect result.
+
+GIT
+---
+Part of the linkgit:git[1] suite

Documentation/git-sparse-checkout.txt

@@ -31,13 +31,21 @@ COMMANDS
 	Describe the patterns in the sparse-checkout file.
 
 'set'::
-	Enable the necessary config settings
-	(extensions.worktreeConfig, core.sparseCheckout,
-	core.sparseCheckoutCone) if they are not already enabled, and
-	write a set of patterns to the sparse-checkout file from the
+	Enable the necessary sparse-checkout config settings
+	(`core.sparseCheckout`, `core.sparseCheckoutCone`, and
+	`index.sparse`) if they are not already set to the desired values,
+	and write a set of patterns to the sparse-checkout file from the
 	list of arguments following the 'set' subcommand. Update the
 	working directory to match the new patterns.
 +
+To ensure that adjusting the sparse-checkout settings within a worktree
+does not alter the sparse-checkout settings in other worktrees, the 'set'
+subcommand will upgrade your repository config to use worktree-specific
+config if not already present. The sparsity defined by the arguments to
+the 'set' subcommand are stored in the worktree-specific sparse-checkout
+file. See linkgit:git-worktree[1] and the documentation of
+`extensions.worktreeConfig` in linkgit:git-config[1] for more details.
++
 When the `--stdin` option is provided, the patterns are read from
 standard in as a newline-delimited list instead of from the arguments.
 +

Documentation/git-submodule.txt

@@ -133,7 +133,7 @@ If you really want to remove a submodule from the repository and commit
 that use linkgit:git-rm[1] instead. See linkgit:gitsubmodules[7] for removal
 options.
 
-update [--init] [--remote] [-N|--no-fetch] [--[no-]recommend-shallow] [-f|--force] [--checkout|--rebase|--merge] [--reference <repository>] [--depth <depth>] [--recursive] [--jobs <n>] [--[no-]single-branch] [--] [<path>...]::
+update [--init] [--remote] [-N|--no-fetch] [--[no-]recommend-shallow] [-f|--force] [--checkout|--rebase|--merge] [--reference <repository>] [--depth <depth>] [--recursive] [--jobs <n>] [--[no-]single-branch] [--filter <filter spec>] [--] [<path>...]::
 +
 --
 Update the registered submodules to match what the superproject
@@ -177,6 +177,10 @@ submodule with the `--init` option.
 
 If `--recursive` is specified, this command will recurse into the
 registered submodules, and update any nested submodules within.
+
+If `--filter <filter spec>` is specified, the given partial clone filter will be
+applied to the submodule. See linkgit:git-rev-list[1] for details on filter
+specifications.
 --
 set-branch (-b|--branch) <branch> [--] <path>::
 set-branch (-d|--default) [--] <path>::

Documentation/git-update-index.txt

@@ -498,7 +498,9 @@ FILE SYSTEM MONITOR
 This feature is intended to speed up git operations for repos that have
 large working directories.
 
-It enables git to work together with a file system monitor (see the
+It enables git to work together with a file system monitor (see
+linkgit:git-fsmonitor--daemon[1]
+and the
 "fsmonitor-watchman" section of linkgit:githooks[5]) that can
 inform it as to what files have been modified. This enables git to avoid
 having to lstat() every file to find modified files.
@@ -509,8 +511,8 @@ looking for new files.
 
 If you want to enable (or disable) this feature, it is easier to use
 the `core.fsmonitor` configuration variable (see
-linkgit:git-config[1]) than using the `--fsmonitor` option to
-`git update-index` in each repository, especially if you want to do so
+linkgit:git-config[1]) than using the `--fsmonitor` option to `git
+update-index` in each repository, especially if you want to do so
 across all repositories you use, because you can set the configuration
 variable in your `$HOME/.gitconfig` just once and have it affect all
 repositories you touch.

Documentation/git-worktree.txt

@@ -286,8 +286,8 @@ CONFIGURATION FILE
 ------------------
 By default, the repository `config` file is shared across all working
 trees. If the config variables `core.bare` or `core.worktree` are
-already present in the config file, they will be applied to the main
-working trees only.
+present in the common config file and `extensions.worktreeConfig` is
+disabled, then they will be applied to the main working tree only.
 
 In order to have configuration specific to working trees, you can turn
 on the `worktreeConfig` extension, e.g.:
@@ -307,11 +307,16 @@ them to the `config.worktree` of the main working tree. You may also
 take this opportunity to review and move other configuration that you
 do not want to share to all working trees:
 
- - `core.worktree` and `core.bare` should never be shared
+ - `core.worktree` should never be shared.
+
+ - `core.bare` should not be shared if the value is `core.bare=true`.
 
  - `core.sparseCheckout` is recommended per working tree, unless you
    are sure you always use sparse checkout for all working trees.
 
+See the documentation of `extensions.worktreeConfig` in
+linkgit:git-config[1] for more details.
+
 DETAILS
 -------
 Each linked working tree has a private sub-directory in the repository's

Documentation/gitattributes.txt

@@ -161,11 +161,12 @@ unspecified.
 
 This attribute sets a specific line-ending style to be used in the
 working directory.  This attribute has effect only if the `text`
-attribute is set or unspecified, or if it is set to `auto` and the file
-is detected as text.  Note that setting this attribute on paths which
-are in the index with CRLF line endings may make the paths to be
-considered dirty. Adding the path to the index again will normalize the
-line endings in the index.
+attribute is set or unspecified, or if it is set to `auto`, the file is
+detected as text, and it is stored with LF endings in the index.  Note
+that setting this attribute on paths which are in the index with CRLF
+line endings may make the paths to be considered dirty unless
+`text=auto` is set. Adding the path to the index again will normalize
+the line endings in the index.
 
 Set to string value "crlf"::
 

Documentation/glossary-content.txt

@@ -312,7 +312,7 @@ Pathspecs are used on the command line of "git ls-files", "git
 ls-tree", "git add", "git grep", "git diff", "git checkout",
 and many other commands to
 limit the scope of operations to some subset of the tree or
-worktree.  See the documentation of each command for whether
+working tree.  See the documentation of each command for whether
 paths are relative to the current directory or toplevel.  The
 pathspec syntax is as follows:
 +
@@ -446,7 +446,7 @@ exclude;;
 	interface than the <<def_plumbing,plumbing>>.
 
 [[def_per_worktree_ref]]per-worktree ref::
-	Refs that are per-<<def_working_tree,worktree>>, rather than
+	Refs that are per-<<def_worktree,worktree>>, rather than
 	global.  This is presently only <<def_HEAD,HEAD>> and any refs
 	that start with `refs/bisect/`, but might later include other
 	unusual refs.
@@ -669,3 +669,12 @@ The most notable example is `HEAD`.
 	The tree of actual checked out files.  The working tree normally
 	contains the contents of the <<def_HEAD,HEAD>> commit's tree,
 	plus any local changes that you have made but not yet committed.
+
+[[def_worktree]]worktree::
+	A repository can have zero (i.e. bare repository) or one or
+	more worktrees attached to it. One "worktree" consists of a
+	"working tree" and repository metadata, most of which are
+	shared among other worktrees of a single repository, and
+	some of which are maintained separately per worktree
+	(e.g. the index, HEAD and pseudorefs like MERGE_HEAD,
+	per-worktree refs and per-worktree configuration file).

Documentation/rev-list-options.txt

@@ -122,19 +122,27 @@ again.  Equivalent forms are `--min-parents=0` (any commit has 0 or more
 parents) and `--max-parents=-1` (negative numbers denote no upper limit).
 
 --first-parent::
-	Follow only the first parent commit upon seeing a merge
-	commit.  This option can give a better overview when
-	viewing the evolution of a particular topic branch,
-	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.
+	When finding commits to include, follow only the first
+	parent commit upon seeing a merge commit.  This option
+	can give a better overview when viewing the evolution of
+	a particular topic branch, 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.
 ifdef::git-log[]
 +
 This option also changes default diff format for merge commits
 to `first-parent`, see `--diff-merges=first-parent` for details.
 endif::git-log[]
 
+--exclude-first-parent-only::
+	When finding commits to exclude (with a '{caret}'), follow only
+	the first parent commit upon seeing a merge commit.
+	This can be used to find the set of changes in a topic branch
+	from the point where it diverged from the remote branch, given
+	that arbitrary merges can be valid topic branch changes.
+
 --not::
 	Reverses the meaning of the '{caret}' prefix (or lack thereof)
 	for all following revision specifiers, up to the next `--not`.

Makefile

@@ -470,6 +470,11 @@ all::
 # directory, and the JSON compilation database 'compile_commands.json' will be
 # created at the root of the repository.
 #
+# If your platform supports a built-in fsmonitor backend, set
+# FSMONITOR_DAEMON_BACKEND to the "<name>" of the corresponding
+# `compat/fsmonitor/fsm-listen-<name>.c` that implements the
+# `fsm_listen__*()` routines.
+#
 # Define DEVELOPER to enable more compiler warnings. Compiler version
 # and family are auto detected, but could be overridden by defining
 # COMPILER_FEATURES (see config.mak.dev). You can still set
@@ -711,6 +716,7 @@ TEST_BUILTINS_OBJS += test-dump-split-index.o
 TEST_BUILTINS_OBJS += test-dump-untracked-cache.o
 TEST_BUILTINS_OBJS += test-example-decorate.o
 TEST_BUILTINS_OBJS += test-fast-rebase.o
+TEST_BUILTINS_OBJS += test-fsmonitor-client.o
 TEST_BUILTINS_OBJS += test-genrandom.o
 TEST_BUILTINS_OBJS += test-genzeros.o
 TEST_BUILTINS_OBJS += test-getcwd.o
@@ -907,6 +913,8 @@ LIB_OBJS += fetch-pack.o
 LIB_OBJS += fmt-merge-msg.o
 LIB_OBJS += fsck.o
 LIB_OBJS += fsmonitor.o
+LIB_OBJS += fsmonitor-ipc.o
+LIB_OBJS += fsmonitor-settings.o
 LIB_OBJS += gettext.o
 LIB_OBJS += gpg-interface.o
 LIB_OBJS += graph.o
@@ -1112,6 +1120,7 @@ BUILTIN_OBJS += builtin/fmt-merge-msg.o
 BUILTIN_OBJS += builtin/for-each-ref.o
 BUILTIN_OBJS += builtin/for-each-repo.o
 BUILTIN_OBJS += builtin/fsck.o
+BUILTIN_OBJS += builtin/fsmonitor--daemon.o
 BUILTIN_OBJS += builtin/gc.o
 BUILTIN_OBJS += builtin/get-tar-commit-id.o
 BUILTIN_OBJS += builtin/grep.o
@@ -1965,6 +1974,11 @@ ifdef NEED_ACCESS_ROOT_HANDLER
 	COMPAT_OBJS += compat/access.o
 endif
 
+ifdef FSMONITOR_DAEMON_BACKEND
+	COMPAT_CFLAGS += -DHAVE_FSMONITOR_DAEMON_BACKEND
+	COMPAT_OBJS += compat/fsmonitor/fsm-listen-$(FSMONITOR_DAEMON_BACKEND).o
+endif
+
 ifeq ($(TCLTK_PATH),)
 NO_TCLTK = NoThanks
 endif
@@ -2884,6 +2898,9 @@ GIT-BUILD-OPTIONS: FORCE
 	@echo DC_SHA1=\''$(subst ','\'',$(subst ','\'',$(DC_SHA1)))'\' >>$@+
 	@echo SANITIZE_LEAK=\''$(subst ','\'',$(subst ','\'',$(SANITIZE_LEAK)))'\' >>$@+
 	@echo X=\'$(X)\' >>$@+
+ifdef FSMONITOR_DAEMON_BACKEND
+	@echo FSMONITOR_DAEMON_BACKEND=\''$(subst ','\'',$(subst ','\'',$(FSMONITOR_DAEMON_BACKEND)))'\' >>$@+
+endif
 ifdef TEST_OUTPUT_DIRECTORY
 	@echo TEST_OUTPUT_DIRECTORY=\''$(subst ','\'',$(subst ','\'',$(TEST_OUTPUT_DIRECTORY)))'\' >>$@+
 endif

add-interactive.c

@@ -797,14 +797,14 @@ static int run_revert(struct add_i_state *s, const struct pathspec *ps,
 	diffopt.flags.override_submodule_config = 1;
 	diffopt.repo = s->r;
 
-	if (do_diff_cache(&oid, &diffopt))
+	if (do_diff_cache(&oid, &diffopt)) {
+		diff_free(&diffopt);
 		res = -1;
-	else {
+	} else {
 		diffcore_std(&diffopt);
 		diff_flush(&diffopt);
 	}
 	free(paths);
-	clear_pathspec(&diffopt.pathspec);
 
 	if (!res && write_locked_index(s->r->index, &index_lock,
 				       COMMIT_LOCK) < 0)

advice.c

@@ -70,6 +70,7 @@ static struct {
 	[ADVICE_STATUS_HINTS]				= { "statusHints", 1 },
 	[ADVICE_STATUS_U_OPTION]			= { "statusUoption", 1 },
 	[ADVICE_SUBMODULE_ALTERNATE_ERROR_STRATEGY_DIE] = { "submoduleAlternateErrorStrategyDie", 1 },
+	[ADVICE_SUBMODULES_NOT_UPDATED] 		= { "submodulesNotUpdated", 1 },
 	[ADVICE_UPDATE_SPARSE_PATH]			= { "updateSparsePath", 1 },
 	[ADVICE_WAITING_FOR_EDITOR]			= { "waitingForEditor", 1 },
 };

advice.h

@@ -44,6 +44,7 @@ struct string_list;
 	ADVICE_STATUS_HINTS,
 	ADVICE_STATUS_U_OPTION,
 	ADVICE_SUBMODULE_ALTERNATE_ERROR_STRATEGY_DIE,
+	ADVICE_SUBMODULES_NOT_UPDATED,
 	ADVICE_UPDATE_SPARSE_PATH,
 	ADVICE_WAITING_FOR_EDITOR,
 	ADVICE_SKIPPED_CHERRY_PICKS,

archive-zip.c

@@ -9,6 +9,7 @@
 #include "object-store.h"
 #include "userdiff.h"
 #include "xdiff-interface.h"
+#include "date.h"
 
 static int zip_date;
 static int zip_time;

archive.c

@@ -12,7 +12,7 @@
 
 static char const * const archive_usage[] = {
 	N_("git archive [<options>] <tree-ish> [<path>...]"),
-	N_("git archive --list"),
+	"git archive --list",
 	N_("git archive --remote <repo> [--exec <cmd>] [<options>] <tree-ish> [<path>...]"),
 	N_("git archive --remote <repo> [--exec <cmd>] --list"),
 	NULL

blame.c

@@ -1403,7 +1403,6 @@ static struct blame_origin *find_origin(struct repository *r,
 		}
 	}
 	diff_flush(&diff_opts);
-	clear_pathspec(&diff_opts.pathspec);
 	return porigin;
 }
 
@@ -1447,7 +1446,6 @@ static struct blame_origin *find_rename(struct repository *r,
 		}
 	}
 	diff_flush(&diff_opts);
-	clear_pathspec(&diff_opts.pathspec);
 	return porigin;
 }
 
@@ -2328,7 +2326,6 @@ static void find_copy_in_parent(struct blame_scoreboard *sb,
 	} while (unblamed);
 	target->suspects = reverse_blame(leftover, NULL);
 	diff_flush(&diff_opts);
-	clear_pathspec(&diff_opts.pathspec);
 }
 
 /*
@@ -2615,7 +2612,7 @@ void assign_blame(struct blame_scoreboard *sb, int opt)
 		else {
 			commit->object.flags |= UNINTERESTING;
 			if (commit->object.parsed)
-				mark_parents_uninteresting(commit);
+				mark_parents_uninteresting(sb->revs, commit);
 		}
 		/* treat root commit as boundary */
 		if (!commit->parents && !sb->show_root)

branch.c

@@ -8,6 +8,8 @@
 #include "sequencer.h"
 #include "commit.h"
 #include "worktree.h"
+#include "submodule-config.h"
+#include "run-command.h"
 
 struct tracking {
 	struct refspec_item spec;
@@ -218,9 +220,11 @@ static int inherit_tracking(struct tracking *tracking, const char *orig_ref)
 }
 
 /*
- * This is called when new_ref is branched off of orig_ref, and tries
- * to infer the settings for branch.<new_ref>.{remote,merge} from the
- * config.
+ * Used internally to set the branch.<new_ref>.{remote,merge} config
+ * settings so that branch 'new_ref' tracks 'orig_ref'. Unlike
+ * dwim_and_setup_tracking(), this does not do DWIM, i.e. "origin/main"
+ * will not be expanded to "refs/remotes/origin/main", so it is not safe
+ * for 'orig_ref' to be raw user input.
  */
 static void setup_tracking(const char *new_ref, const char *orig_ref,
 			   enum branch_track track, int quiet)
@@ -235,7 +239,7 @@ static void setup_tracking(const char *new_ref, const char *orig_ref,
 	if (track != BRANCH_TRACK_INHERIT)
 		for_each_remote(find_tracked_branch, &tracking);
 	else if (inherit_tracking(&tracking, orig_ref))
-		return;
+		goto cleanup;
 
 	if (!tracking.matches)
 		switch (track) {
@@ -245,7 +249,7 @@ static void setup_tracking(const char *new_ref, const char *orig_ref,
 		case BRANCH_TRACK_INHERIT:
 			break;
 		default:
-			return;
+			goto cleanup;
 		}
 
 	if (tracking.matches > 1)
@@ -258,7 +262,8 @@ static void setup_tracking(const char *new_ref, const char *orig_ref,
 				tracking.remote, tracking.srcs) < 0)
 		exit(-1);
 
-	string_list_clear(tracking.srcs, 0);
+cleanup:
+	string_list_clear(&tracking_srcs, 0);
 }
 
 int read_branch_desc(struct strbuf *buf, const char *branch_name)
@@ -346,31 +351,37 @@ N_("\n"
 "will track its remote counterpart, you may want to use\n"
 "\"git push -u\" to set the upstream config as you push.");
 
-void create_branch(struct repository *r,
-		   const char *name, const char *start_name,
-		   int force, int clobber_head_ok, int reflog,
-		   int quiet, enum branch_track track)
+/**
+ * DWIMs a user-provided ref to determine the starting point for a
+ * branch and validates it, where:
+ *
+ *   - r is the repository to validate the branch for
+ *
+ *   - start_name is the ref that we would like to test. This is
+ *     expanded with DWIM and assigned to out_real_ref.
+ *
+ *   - track is the tracking mode of the new branch. If tracking is
+ *     explicitly requested, start_name must be a branch (because
+ *     otherwise start_name cannot be tracked)
+ *
+ *   - out_oid is an out parameter containing the object_id of start_name
+ *
+ *   - out_real_ref is an out parameter containing the full, 'real' form
+ *     of start_name e.g. refs/heads/main instead of main
+ *
+ */
+static void dwim_branch_start(struct repository *r, const char *start_name,
+			   enum branch_track track, char **out_real_ref,
+			   struct object_id *out_oid)
 {
 	struct commit *commit;
 	struct object_id oid;
 	char *real_ref;
-	struct strbuf ref = STRBUF_INIT;
-	int forcing = 0;
-	int dont_change_ref = 0;
 	int explicit_tracking = 0;
 
 	if (track == BRANCH_TRACK_EXPLICIT || track == BRANCH_TRACK_OVERRIDE)
 		explicit_tracking = 1;
 
-	if ((track == BRANCH_TRACK_OVERRIDE || clobber_head_ok)
-	    ? validate_branchname(name, &ref)
-	    : validate_new_branchname(name, &ref, force)) {
-		if (!force)
-			dont_change_ref = 1;
-		else
-			forcing = 1;
-	}
-
 	real_ref = NULL;
 	if (get_oid_mb(start_name, &oid)) {
 		if (explicit_tracking) {
@@ -407,40 +418,218 @@ void create_branch(struct repository *r,
 
 	if ((commit = lookup_commit_reference(r, &oid)) == NULL)
 		die(_("not a valid branch point: '%s'"), start_name);
-	oidcpy(&oid, &commit->object.oid);
+	if (out_real_ref) {
+		*out_real_ref = real_ref;
+		real_ref = NULL;
+	}
+	if (out_oid)
+		oidcpy(out_oid, &commit->object.oid);
+
+	FREE_AND_NULL(real_ref);
+}
+
+void create_branch(struct repository *r,
+		   const char *name, const char *start_name,
+		   int force, int clobber_head_ok, int reflog,
+		   int quiet, enum branch_track track, int dry_run)
+{
+	struct object_id oid;
+	char *real_ref;
+	struct strbuf ref = STRBUF_INIT;
+	int forcing = 0;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
+	char *msg;
+
+	if (track == BRANCH_TRACK_OVERRIDE)
+		BUG("'track' cannot be BRANCH_TRACK_OVERRIDE. Did you mean to call dwim_and_setup_tracking()?");
+	if (clobber_head_ok && !force)
+		BUG("'clobber_head_ok' can only be used with 'force'");
+
+	if (clobber_head_ok ?
+			  validate_branchname(name, &ref) :
+			  validate_new_branchname(name, &ref, force)) {
+		forcing = 1;
+	}
+
+	dwim_branch_start(r, start_name, track, &real_ref, &oid);
+	if (dry_run)
+		goto cleanup;
 
 	if (reflog)
 		log_all_ref_updates = LOG_REFS_NORMAL;
 
-	if (!dont_change_ref) {
-		struct ref_transaction *transaction;
-		struct strbuf err = STRBUF_INIT;
-		char *msg;
-
-		if (forcing)
-			msg = xstrfmt("branch: Reset to %s", start_name);
-		else
-			msg = xstrfmt("branch: Created from %s", start_name);
-
-		transaction = ref_transaction_begin(&err);
-		if (!transaction ||
-		    ref_transaction_update(transaction, ref.buf,
-					   &oid, forcing ? NULL : null_oid(),
-					   0, msg, &err) ||
-		    ref_transaction_commit(transaction, &err))
-			die("%s", err.buf);
-		ref_transaction_free(transaction);
-		strbuf_release(&err);
-		free(msg);
-	}
+	if (forcing)
+		msg = xstrfmt("branch: Reset to %s", start_name);
+	else
+		msg = xstrfmt("branch: Created from %s", start_name);
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+		ref_transaction_update(transaction, ref.buf,
+					&oid, forcing ? NULL : null_oid(),
+					0, msg, &err) ||
+		ref_transaction_commit(transaction, &err))
+		die("%s", err.buf);
+	ref_transaction_free(transaction);
+	strbuf_release(&err);
+	free(msg);
 
 	if (real_ref && track)
 		setup_tracking(ref.buf + 11, real_ref, track, quiet);
 
+cleanup:
 	strbuf_release(&ref);
 	free(real_ref);
 }
 
+void dwim_and_setup_tracking(struct repository *r, const char *new_ref,
+			     const char *orig_ref, enum branch_track track,
+			     int quiet)
+{
+	char *real_orig_ref;
+	dwim_branch_start(r, orig_ref, track, &real_orig_ref, NULL);
+	setup_tracking(new_ref, real_orig_ref, track, quiet);
+}
+
+/**
+ * Creates a branch in a submodule by calling
+ * create_branches_recursively() in a child process. The child process
+ * is necessary because install_branch_config_multiple_remotes() (which
+ * is called by setup_tracking()) does not support writing configs to
+ * submodules.
+ */
+static int submodule_create_branch(struct repository *r,
+				   const struct submodule *submodule,
+				   const char *name, const char *start_oid,
+				   const char *tracking_name, int force,
+				   int reflog, int quiet,
+				   enum branch_track track, int dry_run)
+{
+	int ret = 0;
+	struct child_process child = CHILD_PROCESS_INIT;
+	struct strbuf child_err = STRBUF_INIT;
+	struct strbuf out_buf = STRBUF_INIT;
+	char *out_prefix = xstrfmt("submodule '%s': ", submodule->name);
+	child.git_cmd = 1;
+	child.err = -1;
+	child.stdout_to_stderr = 1;
+
+	prepare_other_repo_env(&child.env_array, r->gitdir);
+	/*
+	 * submodule_create_branch() is indirectly invoked by "git
+	 * branch", but we cannot invoke "git branch" in the child
+	 * process. "git branch" accepts a branch name and start point,
+	 * where the start point is assumed to provide both the OID
+	 * (start_oid) and the branch to use for tracking
+	 * (tracking_name). But when recursing through submodules,
+	 * start_oid and tracking name need to be specified separately
+	 * (see create_branches_recursively()).
+	 */
+	strvec_pushl(&child.args, "submodule--helper", "create-branch", NULL);
+	if (dry_run)
+		strvec_push(&child.args, "--dry-run");
+	if (force)
+		strvec_push(&child.args, "--force");
+	if (quiet)
+		strvec_push(&child.args, "--quiet");
+	if (reflog)
+		strvec_push(&child.args, "--create-reflog");
+	if (track == BRANCH_TRACK_ALWAYS || track == BRANCH_TRACK_EXPLICIT)
+		strvec_push(&child.args, "--track");
+
+	strvec_pushl(&child.args, name, start_oid, tracking_name, NULL);
+
+	if ((ret = start_command(&child)))
+		return ret;
+	ret = finish_command(&child);
+	strbuf_read(&child_err, child.err, 0);
+	strbuf_add_lines(&out_buf, out_prefix, child_err.buf, child_err.len);
+
+	if (ret)
+		fprintf(stderr, "%s", out_buf.buf);
+	else
+		printf("%s", out_buf.buf);
+
+	strbuf_release(&child_err);
+	strbuf_release(&out_buf);
+	return ret;
+}
+
+void create_branches_recursively(struct repository *r, const char *name,
+				 const char *start_commitish,
+				 const char *tracking_name, int force,
+				 int reflog, int quiet, enum branch_track track,
+				 int dry_run)
+{
+	int i = 0;
+	char *branch_point = NULL;
+	struct object_id super_oid;
+	struct submodule_entry_list submodule_entry_list;
+
+	/* Perform dwim on start_commitish to get super_oid and branch_point. */
+	dwim_branch_start(r, start_commitish, BRANCH_TRACK_NEVER,
+			  &branch_point, &super_oid);
+
+	/*
+	 * If we were not given an explicit name to track, then assume we are at
+	 * the top level and, just like the non-recursive case, the tracking
+	 * name is the branch point.
+	 */
+	if (!tracking_name)
+		tracking_name = branch_point;
+
+	submodules_of_tree(r, &super_oid, &submodule_entry_list);
+	/*
+	 * Before creating any branches, first check that the branch can
+	 * be created in every submodule.
+	 */
+	for (i = 0; i < submodule_entry_list.entry_nr; i++) {
+		if (submodule_entry_list.entries[i].repo == NULL) {
+			if (advice_enabled(ADVICE_SUBMODULES_NOT_UPDATED))
+				advise(_("You may try updating the submodules using 'git checkout %s && git submodule update --init'"),
+				       start_commitish);
+			die(_("submodule '%s': unable to find submodule"),
+			    submodule_entry_list.entries[i].submodule->name);
+		}
+
+		if (submodule_create_branch(
+			    submodule_entry_list.entries[i].repo,
+			    submodule_entry_list.entries[i].submodule, name,
+			    oid_to_hex(&submodule_entry_list.entries[i]
+						.name_entry->oid),
+			    tracking_name, force, reflog, quiet, track, 1))
+			die(_("submodule '%s': cannot create branch '%s'"),
+			    submodule_entry_list.entries[i].submodule->name,
+			    name);
+	}
+
+	create_branch(the_repository, name, start_commitish, force, 0, reflog, quiet,
+		      BRANCH_TRACK_NEVER, dry_run);
+	if (dry_run)
+		return;
+	/*
+	 * NEEDSWORK If tracking was set up in the superproject but not the
+	 * submodule, users might expect "git branch --recurse-submodules" to
+	 * fail or give a warning, but this is not yet implemented because it is
+	 * tedious to determine whether or not tracking was set up in the
+	 * superproject.
+	 */
+	setup_tracking(name, tracking_name, track, quiet);
+
+	for (i = 0; i < submodule_entry_list.entry_nr; i++) {
+		if (submodule_create_branch(
+			    submodule_entry_list.entries[i].repo,
+			    submodule_entry_list.entries[i].submodule, name,
+			    oid_to_hex(&submodule_entry_list.entries[i]
+						.name_entry->oid),
+			    tracking_name, force, reflog, quiet, track, 0))
+			die(_("submodule '%s': cannot create branch '%s'"),
+			    submodule_entry_list.entries[i].submodule->name,
+			    name);
+		repo_clear(submodule_entry_list.entries[i].repo);
+	}
+}
+
 void remove_merge_branch_state(struct repository *r)
 {
 	unlink(git_path_merge_head(r));

branch.h

@@ -18,6 +18,28 @@ extern enum branch_track git_branch_track;
 
 /* Functions for acting on the information about branches. */
 
+/**
+ * Sets branch.<new_ref>.{remote,merge} config settings such that
+ * new_ref tracks orig_ref according to the specified tracking mode.
+ *
+ *   - new_ref is the name of the branch that we are setting tracking
+ *     for.
+ *
+ *   - orig_ref is the name of the ref that is 'upstream' of new_ref.
+ *     orig_ref will be expanded with DWIM so that the config settings
+ *     are in the correct format e.g. "refs/remotes/origin/main" instead
+ *     of "origin/main".
+ *
+ *   - track is the tracking mode e.g. BRANCH_TRACK_REMOTE causes
+ *     new_ref to track orig_ref directly, whereas BRANCH_TRACK_INHERIT
+ *     causes new_ref to track whatever orig_ref tracks.
+ *
+ *   - quiet suppresses tracking information.
+ */
+void dwim_and_setup_tracking(struct repository *r, const char *new_ref,
+			     const char *orig_ref, enum branch_track track,
+			     int quiet);
+
 /*
  * Creates a new branch, where:
  *
@@ -30,8 +52,8 @@ extern enum branch_track git_branch_track;
  *
  *   - force enables overwriting an existing (non-head) branch
  *
- *   - clobber_head_ok allows the currently checked out (hence existing)
- *     branch to be overwritten; without 'force', it has no effect.
+ *   - clobber_head_ok, when enabled with 'force', allows the currently
+ *     checked out (head) branch to be overwritten
  *
  *   - reflog creates a reflog for the branch
  *
@@ -40,12 +62,44 @@ extern enum branch_track git_branch_track;
  *   - track causes the new branch to be configured to merge the remote branch
  *     that start_name is a tracking branch for (if any).
  *
+ *   - dry_run causes the branch to be validated but not created.
+ *
  */
 void create_branch(struct repository *r,
 		   const char *name, const char *start_name,
 		   int force, int clobber_head_ok,
-		   int reflog, int quiet, enum branch_track track);
+		   int reflog, int quiet, enum branch_track track,
+		   int dry_run);
 
+/*
+ * Creates a new branch in a repository and its submodules (and its
+ * submodules, recursively). The parameters are mostly analogous to
+ * those of create_branch() except for start_name, which is represented
+ * by two different parameters:
+ *
+ * - start_commitish is the commit-ish, in repository r, that determines
+ *   which commits the branches will point to. The superproject branch
+ *   will point to the commit of start_commitish and the submodule
+ *   branches will point to the gitlink commit oids in start_commitish's
+ *   tree.
+ *
+ * - tracking_name is the name of the ref, in repository r, that will be
+ *   used to set up tracking information. This value is propagated to
+ *   all submodules, which will evaluate the ref using their own ref
+ *   stores. If NULL, this defaults to start_commitish.
+ *
+ * When this function is called on the superproject, start_commitish
+ * can be any user-provided ref and tracking_name can be NULL (similar
+ * to create_branches()). But when recursing through submodules,
+ * start_commitish is the plain gitlink commit oid. Since the oid cannot
+ * be used for tracking information, tracking_name is propagated and
+ * used for tracking instead.
+ */
+void create_branches_recursively(struct repository *r, const char *name,
+				 const char *start_commitish,
+				 const char *tracking_name, int force,
+				 int reflog, int quiet, enum branch_track track,
+				 int dry_run);
 /*
  * Check if 'name' can be a valid name for a branch; die otherwise.
  * Return 1 if the named branch already exists; return 0 otherwise.

builtin.h

@@ -159,6 +159,7 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix);
 int cmd_for_each_repo(int argc, const char **argv, const char *prefix);
 int cmd_format_patch(int argc, const char **argv, const char *prefix);
 int cmd_fsck(int argc, const char **argv, const char *prefix);
+int cmd_fsmonitor__daemon(int argc, const char **argv, const char *prefix);
 int cmd_gc(int argc, const char **argv, const char *prefix);
 int cmd_get_tar_commit_id(int argc, const char **argv, const char *prefix);
 int cmd_grep(int argc, const char **argv, const char *prefix);

builtin/am.c

@@ -34,6 +34,7 @@
 #include "string-list.h"
 #include "packfile.h"
 #include "repository.h"
+#include "pretty.h"
 
 /**
  * Returns the length of the first line of msg.
@@ -199,7 +200,7 @@ static int am_option_parse_empty(const struct option *opt,
 	else if (!strcmp(arg, "keep"))
 		*opt_value = KEEP_EMPTY_COMMIT;
 	else
-		return error(_("Invalid value for --empty: %s"), arg);
+		return error(_("invalid value for '%s': '%s'"), "--empty", arg);
 
 	return 0;
 }
@@ -2239,7 +2240,8 @@ static int parse_opt_patchformat(const struct option *opt, const char *arg, int
 	 * when you add new options
 	 */
 	else
-		return error(_("Invalid value for --patch-format: %s"), arg);
+		return error(_("invalid value for '%s': '%s'"),
+			     "--patch-format", arg);
 	return 0;
 }
 
@@ -2282,7 +2284,8 @@ static int parse_opt_show_current_patch(const struct option *opt, const char *ar
 				break;
 		}
 		if (new_value >= ARRAY_SIZE(valid_modes))
-			return error(_("Invalid value for --show-current-patch: %s"), arg);
+			return error(_("invalid value for '%s': '%s'"),
+				     "--show-current-patch", arg);
 	}
 
 	if (resume->mode == RESUME_SHOW_PATCH && new_value != resume->sub_mode)

builtin/bisect--helper.c

@@ -22,15 +22,15 @@ static GIT_PATH_FUNC(git_path_bisect_run, "BISECT_RUN")
 
 static const char * const git_bisect_helper_usage[] = {
 	N_("git bisect--helper --bisect-reset [<commit>]"),
-	N_("git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]"),
+	"git bisect--helper --bisect-terms [--term-good | --term-old | --term-bad | --term-new]",
 	N_("git bisect--helper --bisect-start [--term-{new,bad}=<term> --term-{old,good}=<term>]"
 					    " [--no-checkout] [--first-parent] [<bad> [<good>...]] [--] [<paths>...]"),
-	N_("git bisect--helper --bisect-next"),
+	"git bisect--helper --bisect-next",
 	N_("git bisect--helper --bisect-state (bad|new) [<rev>]"),
 	N_("git bisect--helper --bisect-state (good|old) [<rev>...]"),
 	N_("git bisect--helper --bisect-replay <filename>"),
 	N_("git bisect--helper --bisect-skip [(<rev>|<range>)...]"),
-	N_("git bisect--helper --bisect-visualize"),
+	"git bisect--helper --bisect-visualize",
 	N_("git bisect--helper --bisect-run <cmd>..."),
 	NULL
 };

builtin/blame.c

@@ -721,8 +721,8 @@ static int git_blame_config(const char *var, const char *value, void *cb)
 	}
 	if (!strcmp(var, "color.blame.repeatedlines")) {
 		if (color_parse_mem(value, strlen(value), repeated_meta_color))
-			warning(_("invalid color '%s' in color.blame.repeatedLines"),
-				value);
+			warning(_("invalid value for '%s': '%s'"),
+				"color.blame.repeatedLines", value);
 		return 0;
 	}
 	if (!strcmp(var, "color.blame.highlightrecent")) {
@@ -739,7 +739,8 @@ static int git_blame_config(const char *var, const char *value, void *cb)
 			coloring_mode &= ~(OUTPUT_COLOR_LINE |
 					    OUTPUT_SHOW_AGE_WITH_COLOR);
 		} else {
-			warning(_("invalid value for blame.coloring"));
+			warning(_("invalid value for '%s': '%s'"),
+				"blame.coloring", value);
 			return 0;
 		}
 	}
@@ -934,6 +935,7 @@ int cmd_blame(int argc, const char **argv, const char *prefix)
 		parse_revision_opt(&revs, &ctx, options, blame_opt_usage);
 	}
 parse_done:
+	revision_opts_finish(&revs);
 	no_whole_file_rename = !revs.diffopt.flags.follow_renames;
 	xdl_opts |= revs.diffopt.xdl_opts & XDF_INDENT_HEURISTIC;
 	revs.diffopt.flags.follow_renames = 0;

builtin/branch.c

@@ -27,7 +27,8 @@
 
 static const char * const builtin_branch_usage[] = {
 	N_("git branch [<options>] [-r | -a] [--merged] [--no-merged]"),
-	N_("git branch [<options>] [-l] [-f] <branch-name> [<start-point>]"),
+	N_("git branch [<options>] [-f] [--recurse-submodules] <branch-name> [<start-point>]"),
+	N_("git branch [<options>] [-l] [<pattern>...]"),
 	N_("git branch [<options>] [-r] (-d | -D) <branch-name>..."),
 	N_("git branch [<options>] (-m | -M) [<old-branch>] <new-branch>"),
 	N_("git branch [<options>] (-c | -C) [<old-branch>] <new-branch>"),
@@ -38,6 +39,8 @@ static const char * const builtin_branch_usage[] = {
 
 static const char *head;
 static struct object_id head_oid;
+static int recurse_submodules = 0;
+static int submodule_propagate_branches = 0;
 
 static int branch_use_color = -1;
 static char branch_colors[][COLOR_MAXLEN] = {
@@ -99,6 +102,15 @@ static int git_branch_config(const char *var, const char *value, void *cb)
 			return config_error_nonbool(var);
 		return color_parse(value, branch_colors[slot]);
 	}
+	if (!strcmp(var, "submodule.recurse")) {
+		recurse_submodules = git_config_bool(var, value);
+		return 0;
+	}
+	if (!strcasecmp(var, "submodule.propagateBranches")) {
+		submodule_propagate_branches = git_config_bool(var, value);
+		return 0;
+	}
+
 	return git_color_default_config(var, value, cb);
 }
 
@@ -621,14 +633,16 @@ static int edit_branch_description(const char *branch_name)
 
 int cmd_branch(int argc, const char **argv, const char *prefix)
 {
-	int delete = 0, rename = 0, copy = 0, force = 0, list = 0;
-	int show_current = 0;
-	int reflog = 0, edit_description = 0;
-	int quiet = 0, unset_upstream = 0;
+	/* possible actions */
+	int delete = 0, rename = 0, copy = 0, list = 0,
+	    unset_upstream = 0, show_current = 0, edit_description = 0;
 	const char *new_upstream = NULL;
+	int noncreate_actions = 0;
+	/* possible options */
+	int reflog = 0, quiet = 0, icase = 0, force = 0,
+	    recurse_submodules_explicit = 0;
 	enum branch_track track;
 	struct ref_filter filter;
-	int icase = 0;
 	static struct ref_sorting *sorting;
 	struct string_list sorting_options = STRING_LIST_INIT_DUP;
 	struct ref_format format = REF_FORMAT_INIT;
@@ -677,6 +691,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 		OPT_CALLBACK(0, "points-at", &filter.points_at, N_("object"),
 			N_("print only branches of the object"), parse_opt_object_name),
 		OPT_BOOL('i', "ignore-case", &icase, N_("sorting and filtering are case insensitive")),
+		OPT_BOOL(0, "recurse-submodules", &recurse_submodules_explicit, N_("recurse through submodules")),
 		OPT_STRING(  0 , "format", &format.format, N_("format"), N_("format to use for the output")),
 		OPT_END(),
 	};
@@ -713,10 +728,23 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 	    filter.reachable_from || filter.unreachable_from || filter.points_at.nr)
 		list = 1;
 
-	if (!!delete + !!rename + !!copy + !!new_upstream + !!show_current +
-	    list + edit_description + unset_upstream > 1)
+	noncreate_actions = !!delete + !!rename + !!copy + !!new_upstream +
+			    !!show_current + !!list + !!edit_description +
+			    !!unset_upstream;
+	if (noncreate_actions > 1)
 		usage_with_options(builtin_branch_usage, options);
 
+	if (recurse_submodules_explicit) {
+		if (!submodule_propagate_branches)
+			die(_("branch with --recurse-submodules can only be used if submodule.propagateBranches is enabled"));
+		if (noncreate_actions)
+			die(_("--recurse-submodules can only be used to create branches"));
+	}
+
+	recurse_submodules =
+		(recurse_submodules || recurse_submodules_explicit) &&
+		submodule_propagate_branches;
+
 	if (filter.abbrev == -1)
 		filter.abbrev = DEFAULT_ABBREV;
 	filter.ignore_case = icase;
@@ -828,12 +856,9 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 		if (!ref_exists(branch->refname))
 			die(_("branch '%s' does not exist"), branch->name);
 
-		/*
-		 * create_branch takes care of setting up the tracking
-		 * info and making sure new_upstream is correct
-		 */
-		create_branch(the_repository, branch->name, new_upstream,
-			      0, 0, 0, quiet, BRANCH_TRACK_OVERRIDE);
+		dwim_and_setup_tracking(the_repository, branch->name,
+					new_upstream, BRANCH_TRACK_OVERRIDE,
+					quiet);
 	} else if (unset_upstream) {
 		struct branch *branch = branch_get(argv[0]);
 		struct strbuf buf = STRBUF_INIT;
@@ -857,7 +882,10 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 		strbuf_addf(&buf, "branch.%s.merge", branch->name);
 		git_config_set_multivar(buf.buf, NULL, NULL, CONFIG_FLAGS_MULTI_REPLACE);
 		strbuf_release(&buf);
-	} else if (argc > 0 && argc <= 2) {
+	} else if (!noncreate_actions && argc > 0 && argc <= 2) {
+		const char *branch_name = argv[0];
+		const char *start_name = argc == 2 ? argv[1] : head;
+
 		if (filter.kind != FILTER_REFS_BRANCHES)
 			die(_("The -a, and -r, options to 'git branch' do not take a branch name.\n"
 				  "Did you mean to use: -a|-r --list <pattern>?"));
@@ -865,10 +893,14 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 		if (track == BRANCH_TRACK_OVERRIDE)
 			die(_("the '--set-upstream' option is no longer supported. Please use '--track' or '--set-upstream-to' instead."));
 
-		create_branch(the_repository,
-			      argv[0], (argc == 2) ? argv[1] : head,
-			      force, 0, reflog, quiet, track);
-
+		if (recurse_submodules) {
+			create_branches_recursively(the_repository, branch_name,
+						    start_name, NULL, force,
+						    reflog, quiet, track, 0);
+			return 0;
+		}
+		create_branch(the_repository, branch_name, start_name, force, 0,
+			      reflog, quiet, track, 0);
 	} else
 		usage_with_options(builtin_branch_usage, options);
 

builtin/checkout-index.c

@@ -7,6 +7,7 @@
 #define USE_THE_INDEX_COMPATIBILITY_MACROS
 #include "builtin.h"
 #include "config.h"
+#include "dir.h"
 #include "lockfile.h"
 #include "quote.h"
 #include "cache-tree.h"
@@ -17,6 +18,7 @@
 #define CHECKOUT_ALL 4
 static int nul_term_line;
 static int checkout_stage; /* default to checkout stage0 */
+static int ignore_skip_worktree; /* default to 0 */
 static int to_tempfile;
 static char topath[4][TEMPORARY_FILENAME_LENGTH + 1];
 
@@ -65,6 +67,8 @@ static int checkout_file(const char *name, const char *prefix)
 	int namelen = strlen(name);
 	int pos = cache_name_pos(name, namelen);
 	int has_same_name = 0;
+	int is_file = 0;
+	int is_skipped = 1;
 	int did_checkout = 0;
 	int errs = 0;
 
@@ -78,6 +82,12 @@ static int checkout_file(const char *name, const char *prefix)
 			break;
 		has_same_name = 1;
 		pos++;
+		if (S_ISSPARSEDIR(ce->ce_mode))
+			break;
+		is_file = 1;
+		if (!ignore_skip_worktree && ce_skip_worktree(ce))
+			break;
+		is_skipped = 0;
 		if (ce_stage(ce) != checkout_stage
 		    && (CHECKOUT_ALL != checkout_stage || !ce_stage(ce)))
 			continue;
@@ -106,6 +116,11 @@ static int checkout_file(const char *name, const char *prefix)
 		fprintf(stderr, "git checkout-index: %s ", name);
 		if (!has_same_name)
 			fprintf(stderr, "is not in the cache");
+		else if (!is_file)
+			fprintf(stderr, "is a sparse directory");
+		else if (is_skipped)
+			fprintf(stderr, "has skip-worktree enabled; "
+					"use '--ignore-skip-worktree-bits' to checkout");
 		else if (checkout_stage)
 			fprintf(stderr, "does not exist at stage %d",
 				checkout_stage);
@@ -121,10 +136,27 @@ static int checkout_all(const char *prefix, int prefix_length)
 	int i, errs = 0;
 	struct cache_entry *last_ce = NULL;
 
-	/* TODO: audit for interaction with sparse-index. */
-	ensure_full_index(&the_index);
 	for (i = 0; i < active_nr ; i++) {
 		struct cache_entry *ce = active_cache[i];
+
+		if (S_ISSPARSEDIR(ce->ce_mode)) {
+			if (!ce_skip_worktree(ce))
+				BUG("sparse directory '%s' does not have skip-worktree set", ce->name);
+
+			/*
+			 * If the current entry is a sparse directory and skip-worktree
+			 * entries are being checked out, expand the index and continue
+			 * the loop on the current index position (now pointing to the
+			 * first entry inside the expanded sparse directory).
+			 */
+			if (ignore_skip_worktree) {
+				ensure_full_index(&the_index);
+				ce = active_cache[i];
+			}
+		}
+
+		if (!ignore_skip_worktree && ce_skip_worktree(ce))
+			continue;
 		if (ce_stage(ce) != checkout_stage
 		    && (CHECKOUT_ALL != checkout_stage || !ce_stage(ce)))
 			continue;
@@ -185,6 +217,8 @@ int cmd_checkout_index(int argc, const char **argv, const char *prefix)
 	struct option builtin_checkout_index_options[] = {
 		OPT_BOOL('a', "all", &all,
 			N_("check out all files in the index")),
+		OPT_BOOL(0, "ignore-skip-worktree-bits", &ignore_skip_worktree,
+			N_("do not skip files with skip-worktree set")),
 		OPT__FORCE(&force, N_("force overwrite of existing files"), 0),
 		OPT__QUIET(&quiet,
 			N_("no warning for existing files and files not in index")),
@@ -212,6 +246,9 @@ int cmd_checkout_index(int argc, const char **argv, const char *prefix)
 	git_config(git_default_config, NULL);
 	prefix_length = prefix ? strlen(prefix) : 0;
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	if (read_cache() < 0) {
 		die("invalid cache");
 	}

builtin/checkout.c

@@ -909,7 +909,8 @@ static void update_refs_for_switch(const struct checkout_opts *opts,
 				      opts->new_branch_force ? 1 : 0,
 				      opts->new_branch_log,
 				      opts->quiet,
-				      opts->track);
+				      opts->track,
+				      0);
 		free(new_branch_info->name);
 		free(new_branch_info->refname);
 		new_branch_info->name = xstrdup(opts->new_branch);
@@ -1607,9 +1608,10 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 	opts->show_progress = -1;
 
 	git_config(git_checkout_config, opts);
-
-	prepare_repo_settings(the_repository);
-	the_repository->settings.command_requires_full_index = 0;
+	if (the_repository->gitdir) {
+		prepare_repo_settings(the_repository);
+		the_repository->settings.command_requires_full_index = 0;
+	}
 
 	opts->track = BRANCH_TRACK_UNSPECIFIED;
 

builtin/clean.c

@@ -1009,6 +1009,9 @@ int cmd_clean(int argc, const char **argv, const char *prefix)
 		dir.flags |= DIR_KEEP_UNTRACKED_CONTENTS;
 	}
 
+	prepare_repo_settings(the_repository);
+	the_repository->settings.command_requires_full_index = 0;
+
 	if (read_cache() < 0)
 		die(_("index file corrupt"));
 

builtin/clone.c

@@ -72,6 +72,8 @@ static int option_dissociate;
 static int max_jobs = -1;
 static struct string_list option_recurse_submodules = STRING_LIST_INIT_NODUP;
 static struct list_objects_filter_options filter_options;
+static int option_filter_submodules = -1;    /* unspecified */
+static int config_filter_submodules = -1;    /* unspecified */
 static struct string_list server_options = STRING_LIST_INIT_NODUP;
 static int option_remote_submodules;
 
@@ -151,6 +153,8 @@ static struct option builtin_clone_options[] = {
 	OPT_SET_INT('6', "ipv6", &family, N_("use IPv6 addresses only"),
 			TRANSPORT_FAMILY_IPV6),
 	OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
+	OPT_BOOL(0, "also-filter-submodules", &option_filter_submodules,
+		    N_("apply partial clone filters to submodules")),
 	OPT_BOOL(0, "remote-submodules", &option_remote_submodules,
 		    N_("any cloned submodules will use their remote-tracking branch")),
 	OPT_BOOL(0, "sparse", &option_sparse_checkout,
@@ -651,7 +655,7 @@ static int git_sparse_checkout_init(const char *repo)
 	return result;
 }
 
-static int checkout(int submodule_progress)
+static int checkout(int submodule_progress, int filter_submodules)
 {
 	struct object_id oid;
 	char *head;
@@ -730,6 +734,10 @@ static int checkout(int submodule_progress)
 			strvec_push(&args, "--no-fetch");
 		}
 
+		if (filter_submodules && filter_options.choice)
+			strvec_pushf(&args, "--filter=%s",
+				     expand_list_objects_filter_spec(&filter_options));
+
 		if (option_single_branch >= 0)
 			strvec_push(&args, option_single_branch ?
 					       "--single-branch" :
@@ -750,6 +758,8 @@ static int git_clone_config(const char *k, const char *v, void *cb)
 	}
 	if (!strcmp(k, "clone.rejectshallow"))
 		config_reject_shallow = git_config_bool(k, v);
+	if (!strcmp(k, "clone.filtersubmodules"))
+		config_filter_submodules = git_config_bool(k, v);
 
 	return git_default_config(k, v, cb);
 }
@@ -872,6 +882,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	struct remote *remote;
 	int err = 0, complete_refs_before_fetch = 1;
 	int submodule_progress;
+	int filter_submodules = 0;
 
 	struct transport_ls_refs_options transport_ls_refs_options =
 		TRANSPORT_LS_REFS_OPTIONS_INIT;
@@ -1067,6 +1078,27 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	if (option_reject_shallow != -1)
 		reject_shallow = option_reject_shallow;
 
+	/*
+	 * If option_filter_submodules is specified from CLI option,
+	 * ignore config_filter_submodules from git_clone_config.
+	 */
+	if (config_filter_submodules != -1)
+		filter_submodules = config_filter_submodules;
+	if (option_filter_submodules != -1)
+		filter_submodules = option_filter_submodules;
+
+	/*
+	 * Exit if the user seems to be doing something silly with submodule
+	 * filter flags (but not with filter configs, as those should be
+	 * set-and-forget).
+	 */
+	if (option_filter_submodules > 0 && !filter_options.choice)
+		die(_("the option '%s' requires '%s'"),
+		    "--also-filter-submodules", "--filter");
+	if (option_filter_submodules > 0 && !option_recurse_submodules.nr)
+		die(_("the option '%s' requires '%s'"),
+		    "--also-filter-submodules", "--recurse-submodules");
+
 	/*
 	 * apply the remote name provided by --origin only after this second
 	 * call to git_config, to ensure it overrides all config-based values.
@@ -1235,7 +1267,8 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	}
 	else {
 		const char *branch;
-		char *ref;
+		const char *ref;
+		char *ref_free = NULL;
 
 		if (option_branch)
 			die(_("Remote branch %s not found in upstream %s"),
@@ -1251,17 +1284,16 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		    skip_prefix(transport_ls_refs_options.unborn_head_target,
 				"refs/heads/", &branch)) {
 			ref = transport_ls_refs_options.unborn_head_target;
-			transport_ls_refs_options.unborn_head_target = NULL;
 			create_symref("HEAD", ref, reflog_msg.buf);
 		} else {
 			branch = git_default_branch_name(0);
-			ref = xstrfmt("refs/heads/%s", branch);
+			ref_free = xstrfmt("refs/heads/%s", branch);
+			ref = ref_free;
 		}
 
 		if (!option_bare)
 			install_branch_config(0, branch, remote_name, ref);
-
-		free(ref);
+		free(ref_free);
 	}
 
 	write_refspec_config(src_ref_prefix, our_head_points_at,
@@ -1300,7 +1332,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	}
 
 	junk_mode = JUNK_LEAVE_REPO;
-	err = checkout(submodule_progress);
+	err = checkout(submodule_progress, filter_submodules);
 
 	free(remote_name);
 	strbuf_release(&reflog_msg);
@@ -1313,7 +1345,6 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	UNLEAK(repo);
 	junk_mode = JUNK_LEAVE_ALL;
 
-	strvec_clear(&transport_ls_refs_options.ref_prefixes);
-	free(transport_ls_refs_options.unborn_head_target);
+	transport_ls_refs_options_release(&transport_ls_refs_options);
 	return err;
 }

builtin/commit.c

@@ -37,6 +37,7 @@
 #include "help.h"
 #include "commit-reach.h"
 #include "commit-graph.h"
+#include "pretty.h"
 
 static const char * const builtin_commit_usage[] = {
 	N_("git commit [<options>] [--] <pathspec>..."),
@@ -1242,8 +1243,6 @@ static int parse_and_validate_options(int argc, const char *argv[],
 				      struct commit *current_head,
 				      struct wt_status *s)
 {
-	int f = 0;
-
 	argc = parse_options(argc, argv, prefix, options, usage, 0);
 	finalize_deferred_config(s);
 
@@ -1251,7 +1250,7 @@ static int parse_and_validate_options(int argc, const char *argv[],
 		force_author = find_author_by_nickname(force_author);
 
 	if (force_author && renew_authorship)
-		die(_("Using both --reset-author and --author does not make sense"));
+		die(_("options '%s' and '%s' cannot be used together"), "--reset-author", "--author");
 
 	if (logfile || have_option_m || use_message)
 		use_editor = 0;
@@ -1268,20 +1267,16 @@ static int parse_and_validate_options(int argc, const char *argv[],
 			die(_("You are in the middle of a rebase -- cannot amend."));
 	}
 	if (fixup_message && squash_message)
-		die(_("Options --squash and --fixup cannot be used together"));
-	if (use_message)
-		f++;
-	if (edit_message)
-		f++;
-	if (fixup_message)
-		f++;
-	if (logfile)
-		f++;
-	if (f > 1)
-		die(_("Only one of -c/-C/-F/--fixup can be used."));
-	if (have_option_m && (edit_message || use_message || logfile))
-		die((_("Option -m cannot be combined with -c/-C/-F.")));
-	if (f || have_option_m)
+		die(_("options '%s' and '%s' cannot be used together"), "--squash", "--fixup");
+	die_for_incompatible_opt4(!!use_message, "-C",
+				  !!edit_message, "-c",
+				  !!logfile, "-F",
+				  !!fixup_message, "--fixup");
+	die_for_incompatible_opt4(have_option_m, "-m",
+				  !!edit_message, "-c",
+				  !!use_message, "-C",
+				  !!logfile, "-F");
+	if (use_message || edit_message || logfile ||fixup_message || have_option_m)
 		template_file = NULL;
 	if (edit_message)
 		use_message = edit_message;
@@ -1306,9 +1301,10 @@ static int parse_and_validate_options(int argc, const char *argv[],
 	if (patch_interactive)
 		interactive = 1;
 
-	if (also + only + all + interactive > 1)
-		die(_("Only one of --include/--only/--all/--interactive/--patch can be used."));
-
+	die_for_incompatible_opt4(also, "-i/--include",
+				  only, "-o/--only",
+				  all, "-a/--all",
+				  interactive, "--interactive/-p/--patch");
 	if (fixup_message) {
 		/*
 		 * We limit --fixup's suboptions to only alpha characters.

builtin/count-objects.c

@@ -87,7 +87,7 @@ static int print_alternate(struct object_directory *odb, void *data)
 }
 
 static char const * const count_objects_usage[] = {
-	N_("git count-objects [-v] [-H | --human-readable]"),
+	"git count-objects [-v] [-H | --human-readable]",
 	NULL
 };
 

builtin/difftool.c

@@ -732,8 +732,9 @@ int cmd_difftool(int argc, const char **argv, const char *prefix)
 	} else if (dir_diff)
 		die(_("options '%s' and '%s' cannot be used together"), "--dir-diff", "--no-index");
 
-	if (use_gui_tool + !!difftool_cmd + !!extcmd > 1)
-		die(_("options '%s', '%s', and '%s' cannot be used together"), "--gui", "--tool", "--extcmd");
+	die_for_incompatible_opt3(use_gui_tool, "--gui",
+				  !!difftool_cmd, "--tool",
+				  !!extcmd, "--extcmd");
 
 	if (use_gui_tool)
 		setenv("GIT_MERGETOOL_GUI", "true", 1);

builtin/fast-export.c

@@ -26,7 +26,7 @@
 #include "commit-slab.h"
 
 static const char *fast_export_usage[] = {
-	N_("git fast-export [rev-list-opts]"),
+	N_("git fast-export [<rev-list-opts>]"),
 	NULL
 };
 

builtin/fast-import.c

@@ -19,6 +19,7 @@
 #include "mem-pool.h"
 #include "commit-reach.h"
 #include "khash.h"
+#include "date.h"
 
 #define PACK_ID_BITS 16
 #define MAX_PACK_ID ((1<<PACK_ID_BITS)-1)

builtin/fetch.c

@@ -764,8 +764,8 @@ static void prepare_format_display(struct ref *ref_map)
 	else if (!strcasecmp(format, "compact"))
 		compact_format = 1;
 	else
-		die(_("configuration fetch.output contains invalid value %s"),
-		    format);
+		die(_("invalid value for '%s': '%s'"),
+		    "fetch.output", format);
 
 	for (rm = ref_map; rm; rm = rm->next) {
 		if (rm->status == REF_STATUS_REJECT_SHALLOW ||
@@ -1094,12 +1094,15 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 	struct ref *rm;
 	char *url;
 	int want_status;
-	int summary_width = transport_summary_width(ref_map);
+	int summary_width = 0;
 
 	rc = open_fetch_head(&fetch_head);
 	if (rc)
 		return -1;
 
+	if (verbosity >= 0)
+		summary_width = transport_summary_width(ref_map);
+
 	if (raw_url)
 		url = transport_anonymize_url(raw_url);
 	else
@@ -1345,7 +1348,6 @@ static int prune_refs(struct refspec *rs, struct ref *ref_map,
 	int url_len, i, result = 0;
 	struct ref *ref, *stale_refs = get_stale_heads(rs, ref_map);
 	char *url;
-	int summary_width = transport_summary_width(stale_refs);
 	const char *dangling_msg = dry_run
 		? _("   (%s will become dangling)")
 		: _("   (%s has become dangling)");
@@ -1374,6 +1376,8 @@ static int prune_refs(struct refspec *rs, struct ref *ref_map,
 	}
 
 	if (verbosity >= 0) {
+		int summary_width = transport_summary_width(stale_refs);
+
 		for (ref = stale_refs; ref; ref = ref->next) {
 			struct strbuf sb = STRBUF_INIT;
 			if (!shown_url) {
@@ -1594,7 +1598,7 @@ static int do_fetch(struct transport *transport,
 	} else
 		remote_refs = NULL;
 
-	strvec_clear(&transport_ls_refs_options.ref_prefixes);
+	transport_ls_refs_options_release(&transport_ls_refs_options);
 
 	ref_map = get_ref_map(transport->remote, remote_refs, rs,
 			      tags, &autotags);
@@ -2017,8 +2021,10 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 	}
 
 	git_config(git_fetch_config, NULL);
-	prepare_repo_settings(the_repository);
-	the_repository->settings.command_requires_full_index = 0;
+	if (the_repository->gitdir) {
+		prepare_repo_settings(the_repository);
+		the_repository->settings.command_requires_full_index = 0;
+	}
 
 	argc = parse_options(argc, argv, prefix,
 			     builtin_fetch_options, builtin_fetch_usage, 0);

builtin/grep.c

@@ -26,6 +26,8 @@
 #include "object-store.h"
 #include "packfile.h"
 
+static const char *grep_prefix;
+
 static char const * const grep_usage[] = {
 	N_("git grep [<options>] [-e] <pattern> [<rev>...] [[--] <path>...]"),
 	NULL
@@ -284,7 +286,7 @@ static int wait_all(void)
 static int grep_cmd_config(const char *var, const char *value, void *cb)
 {
 	int st = grep_config(var, value, cb);
-	if (git_color_default_config(var, value, cb) < 0)
+	if (git_color_default_config(var, value, NULL) < 0)
 		st = -1;
 
 	if (!strcmp(var, "grep.threads")) {
@@ -315,11 +317,11 @@ static void grep_source_name(struct grep_opt *opt, const char *filename,
 	strbuf_reset(out);
 
 	if (opt->null_following_name) {
-		if (opt->relative && opt->prefix_length) {
+		if (opt->relative && grep_prefix) {
 			struct strbuf rel_buf = STRBUF_INIT;
 			const char *rel_name =
 				relative_path(filename + tree_name_len,
-					      opt->prefix, &rel_buf);
+					      grep_prefix, &rel_buf);
 
 			if (tree_name_len)
 				strbuf_add(out, filename, tree_name_len);
@@ -332,8 +334,8 @@ static void grep_source_name(struct grep_opt *opt, const char *filename,
 		return;
 	}
 
-	if (opt->relative && opt->prefix_length)
-		quote_path(filename + tree_name_len, opt->prefix, out, 0);
+	if (opt->relative && grep_prefix)
+		quote_path(filename + tree_name_len, grep_prefix, out, 0);
 	else
 		quote_c_style(filename + tree_name_len, out, NULL, 0);
 
@@ -843,7 +845,6 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	int i;
 	int dummy;
 	int use_index = 1;
-	int pattern_type_arg = GREP_PATTERN_TYPE_UNSPECIFIED;
 	int allow_revs;
 
 	struct option options[] = {
@@ -877,16 +878,16 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			N_("descend at most <depth> levels"), PARSE_OPT_NONEG,
 			NULL, 1 },
 		OPT_GROUP(""),
-		OPT_SET_INT('E', "extended-regexp", &pattern_type_arg,
+		OPT_SET_INT('E', "extended-regexp", &opt.pattern_type_option,
 			    N_("use extended POSIX regular expressions"),
 			    GREP_PATTERN_TYPE_ERE),
-		OPT_SET_INT('G', "basic-regexp", &pattern_type_arg,
+		OPT_SET_INT('G', "basic-regexp", &opt.pattern_type_option,
 			    N_("use basic POSIX regular expressions (default)"),
 			    GREP_PATTERN_TYPE_BRE),
-		OPT_SET_INT('F', "fixed-strings", &pattern_type_arg,
+		OPT_SET_INT('F', "fixed-strings", &opt.pattern_type_option,
 			    N_("interpret patterns as fixed strings"),
 			    GREP_PATTERN_TYPE_FIXED),
-		OPT_SET_INT('P', "perl-regexp", &pattern_type_arg,
+		OPT_SET_INT('P', "perl-regexp", &opt.pattern_type_option,
 			    N_("use Perl-compatible regular expressions"),
 			    GREP_PATTERN_TYPE_PCRE),
 		OPT_GROUP(""),
@@ -962,9 +963,10 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 			   PARSE_OPT_NOCOMPLETE),
 		OPT_END()
 	};
+	grep_prefix = prefix;
 
-	git_config(grep_cmd_config, NULL);
-	grep_init(&opt, the_repository, prefix);
+	grep_init(&opt, the_repository);
+	git_config(grep_cmd_config, &opt);
 
 	/*
 	 * If there is no -- then the paths must exist in the working
@@ -979,7 +981,6 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	argc = parse_options(argc, argv, prefix, options, grep_usage,
 			     PARSE_OPT_KEEP_DASHDASH |
 			     PARSE_OPT_STOP_AT_NON_OPTION);
-	grep_commit_pattern_type(pattern_type_arg, &opt);
 
 	if (use_index && !startup_info->have_repository) {
 		int fallback = 0;
@@ -1167,11 +1168,9 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 	if (!show_in_pager && !opt.status_only)
 		setup_pager();
 
-	if (!use_index && (untracked || cached))
-		die(_("--cached or --untracked cannot be used with --no-index"));
-
-	if (untracked && cached)
-		die(_("--untracked cannot be used with --cached"));
+	die_for_incompatible_opt3(!use_index, "--no-index",
+				  untracked, "--untracked",
+				  cached, "--cached");
 
 	if (!use_index || untracked) {
 		int use_exclude = (opt_exclude < 0) ? use_index : !!opt_exclude;

builtin/hash-object.c

@@ -81,7 +81,7 @@ int cmd_hash_object(int argc, const char **argv, const char *prefix)
 {
 	static const char * const hash_object_usage[] = {
 		N_("git hash-object [-t <type>] [-w] [--path=<file> | --no-filters] [--stdin] [--] <file>..."),
-		N_("git hash-object  --stdin-paths"),
+		"git hash-object  --stdin-paths",
 		NULL
 	};
 	const char *type = blob_type;
@@ -92,6 +92,7 @@ int cmd_hash_object(int argc, const char **argv, const char *prefix)
 	int nongit = 0;
 	unsigned flags = HASH_FORMAT_CHECK;
 	const char *vpath = NULL;
+	char *vpath_free = NULL;
 	const struct option hash_object_options[] = {
 		OPT_STRING('t', NULL, &type, N_("type"), N_("object type")),
 		OPT_BIT('w', NULL, &flags, N_("write the object into the object database"),
@@ -114,8 +115,10 @@ int cmd_hash_object(int argc, const char **argv, const char *prefix)
 	else
 		prefix = setup_git_directory_gently(&nongit);
 
-	if (vpath && prefix)
-		vpath = prefix_filename(prefix, vpath);
+	if (vpath && prefix) {
+		vpath_free = prefix_filename(prefix, vpath);
+		vpath = vpath_free;
+	}
 
 	git_config(git_default_config, NULL);
 
@@ -156,5 +159,7 @@ int cmd_hash_object(int argc, const char **argv, const char *prefix)
 	if (stdin_paths)
 		hash_stdin_paths(type, no_filters, flags, literally);
 
+	free(vpath_free);
+
 	return 0;
 }

builtin/help.c

@@ -77,8 +77,8 @@ static struct option builtin_help_options[] = {
 static const char * const builtin_help_usage[] = {
 	N_("git help [-a|--all] [--[no-]verbose]]\n"
 	   "         [[-i|--info] [-m|--man] [-w|--web]] [<command>]"),
-	N_("git help [-g|--guides]"),
-	N_("git help [-c|--config]"),
+	"git help [-g|--guides]",
+	"git help [-c|--config]",
 	NULL
 };
 

builtin/log.c

@@ -533,8 +533,6 @@ static int git_log_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
-	if (grep_config(var, value, cb) < 0)
-		return -1;
 	if (git_gpg_config(var, value, cb) < 0)
 		return -1;
 	return git_diff_ui_config(var, value, cb);
@@ -549,6 +547,8 @@ int cmd_whatchanged(int argc, const char **argv, const char *prefix)
 	git_config(git_log_config, NULL);
 
 	repo_init_revisions(the_repository, &rev, prefix);
+	git_config(grep_config, &rev.grep_filter);
+
 	rev.diff = 1;
 	rev.simplify_history = 0;
 	memset(&opt, 0, sizeof(opt));
@@ -663,6 +663,8 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 
 	memset(&match_all, 0, sizeof(match_all));
 	repo_init_revisions(the_repository, &rev, prefix);
+	git_config(grep_config, &rev.grep_filter);
+
 	rev.diff = 1;
 	rev.always_show_header = 1;
 	rev.no_walk = 1;
@@ -746,6 +748,8 @@ int cmd_log_reflog(int argc, const char **argv, const char *prefix)
 
 	repo_init_revisions(the_repository, &rev, prefix);
 	init_reflog_walk(&rev.reflog_info);
+	git_config(grep_config, &rev.grep_filter);
+
 	rev.verbose_header = 1;
 	memset(&opt, 0, sizeof(opt));
 	opt.def = "HEAD";
@@ -779,6 +783,8 @@ int cmd_log(int argc, const char **argv, const char *prefix)
 	git_config(git_log_config, NULL);
 
 	repo_init_revisions(the_repository, &rev, prefix);
+	git_config(grep_config, &rev.grep_filter);
+
 	rev.always_show_header = 1;
 	memset(&opt, 0, sizeof(opt));
 	opt.def = "HEAD";
@@ -1861,10 +1867,13 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	extra_hdr.strdup_strings = 1;
 	extra_to.strdup_strings = 1;
 	extra_cc.strdup_strings = 1;
+
 	init_log_defaults();
 	init_display_notes(&notes_opt);
 	git_config(git_format_config, NULL);
 	repo_init_revisions(the_repository, &rev, prefix);
+	git_config(grep_config, &rev.grep_filter);
+
 	rev.show_notes = show_notes;
 	memcpy(&rev.notes_opt, &notes_opt, sizeof(notes_opt));
 	rev.commit_format = CMIT_FMT_EMAIL;
@@ -1993,8 +2002,9 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	if (rev.show_notes)
 		load_display_notes(&rev.notes_opt);
 
-	if (use_stdout + rev.diffopt.close_file + !!output_directory > 1)
-		die(_("options '%s', '%s', and '%s' cannot be used together"), "--stdout", "--output", "--output-directory");
+	die_for_incompatible_opt3(use_stdout, "--stdout",
+				  rev.diffopt.close_file, "--output",
+				  !!output_directory, "--output-directory");
 
 	if (use_stdout) {
 		setup_pager();

builtin/ls-remote.c

@@ -155,6 +155,7 @@ int cmd_ls_remote(int argc, const char **argv, const char *prefix)
 
 	ref_array_clear(&ref_array);
 	if (transport_disconnect(transport))
-		return 1;
+		status = 1;
+	transport_ls_refs_options_release(&transport_options);
 	return status;
 }

builtin/ls-tree.c

@@ -150,7 +150,7 @@ int cmd_ls_tree(int argc, const char **argv, const char *prefix)
 
 	git_config(git_default_config, NULL);
 	ls_tree_prefix = prefix;
-	if (prefix && *prefix)
+	if (prefix)
 		chomp_prefix = strlen(prefix);
 
 	argc = parse_options(argc, argv, prefix, ls_tree_options,

builtin/merge-base.c

@@ -159,12 +159,14 @@ int cmd_merge_base(int argc, const char **argv, const char *prefix)
 		if (argc < 2)
 			usage_with_options(merge_base_usage, options);
 		if (show_all)
-			die("--is-ancestor cannot be used with --all");
+			die(_("options '%s' and '%s' cannot be used together"),
+			    "--is-ancestor", "--all");
 		return handle_is_ancestor(argc, argv);
 	}
 
 	if (cmdmode == 'r' && show_all)
-		die("--independent cannot be used with --all");
+		die(_("options '%s' and '%s' cannot be used together"),
+		    "--independent", "--all");
 
 	if (cmdmode == 'o')
 		return handle_octopus(argc, argv, show_all);

builtin/merge.c

@@ -1568,8 +1568,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 
 		if (autostash)
 			create_autostash(the_repository,
-					 git_path_merge_autostash(the_repository),
-					 "merge");
+					 git_path_merge_autostash(the_repository));
 		if (checkout_fast_forward(the_repository,
 					  &head_commit->object.oid,
 					  &commit->object.oid,
@@ -1640,8 +1639,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 
 	if (autostash)
 		create_autostash(the_repository,
-				 git_path_merge_autostash(the_repository),
-				 "merge");
+				 git_path_merge_autostash(the_repository));
 
 	/* We are going to make a new commit. */
 	git_committer_info(IDENT_STRICT);

builtin/mktag.c

@@ -7,7 +7,7 @@
 #include "config.h"
 
 static char const * const builtin_mktag_usage[] = {
-	N_("git mktag"),
+	"git mktag",
 	NULL
 };
 static int option_strict = 1;

builtin/mktree.c

@@ -63,7 +63,7 @@ static void write_tree(struct object_id *oid)
 }
 
 static const char *mktree_usage[] = {
-	N_("git mktree [-z] [--missing] [--batch]"),
+	"git mktree [-z] [--missing] [--batch]",
 	NULL
 };
 

builtin/name-rev.c

@@ -473,7 +473,7 @@ static void show_name(const struct object *obj,
 static char const * const name_rev_usage[] = {
 	N_("git name-rev [<options>] <commit>..."),
 	N_("git name-rev [<options>] --all"),
-	N_("git name-rev [<options>] --stdin"),
+	N_("git name-rev [<options>] --annotate-stdin"),
 	NULL
 };
 

builtin/notes.c

@@ -32,8 +32,8 @@ static const char * const git_notes_usage[] = {
 	N_("git notes [--ref <notes-ref>] edit [--allow-empty] [<object>]"),
 	N_("git notes [--ref <notes-ref>] show [<object>]"),
 	N_("git notes [--ref <notes-ref>] merge [-v | -q] [-s <strategy>] <notes-ref>"),
-	N_("git notes merge --commit [-v | -q]"),
-	N_("git notes merge --abort [-v | -q]"),
+	"git notes merge --commit [-v | -q]",
+	"git notes merge --abort [-v | -q]",
 	N_("git notes [--ref <notes-ref>] remove [<object>...]"),
 	N_("git notes [--ref <notes-ref>] prune [-n] [-v]"),
 	N_("git notes [--ref <notes-ref>] get-ref"),
@@ -89,7 +89,7 @@ static const char * const git_notes_prune_usage[] = {
 };
 
 static const char * const git_notes_get_ref_usage[] = {
-	N_("git notes get-ref"),
+	"git notes get-ref",
 	NULL
 };
 

builtin/pack-objects.c

@@ -3504,7 +3504,7 @@ static int option_parse_missing_action(const struct option *opt,
 		return 0;
 	}
 
-	die(_("invalid value for --missing"));
+	die(_("invalid value for '%s': '%s'"), "--missing", arg);
 	return 0;
 }
 
@@ -3976,9 +3976,11 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 	read_replace_refs = 0;
 
 	sparse = git_env_bool("GIT_TEST_PACK_SPARSE", -1);
-	prepare_repo_settings(the_repository);
-	if (sparse < 0)
-		sparse = the_repository->settings.pack_use_sparse;
+	if (the_repository->gitdir) {
+		prepare_repo_settings(the_repository);
+		if (sparse < 0)
+			sparse = the_repository->settings.pack_use_sparse;
+	}
 
 	reset_pack_idx_option(&pack_idx_opts);
 	git_config(git_pack_config, NULL);

builtin/patch-id.c

@@ -32,8 +32,12 @@ static int scan_hunk_header(const char *p, int *p_before, int *p_after)
 	n = strspn(q, digits);
 	if (q[n] == ',') {
 		q += n + 1;
+		*p_before = atoi(q);
 		n = strspn(q, digits);
+	} else {
+		*p_before = 1;
 	}
+
 	if (n == 0 || q[n] != ' ' || q[n+1] != '+')
 		return 0;
 
@@ -41,13 +45,14 @@ static int scan_hunk_header(const char *p, int *p_before, int *p_after)
 	n = strspn(r, digits);
 	if (r[n] == ',') {
 		r += n + 1;
+		*p_after = atoi(r);
 		n = strspn(r, digits);
+	} else {
+		*p_after = 1;
 	}
 	if (n == 0)
 		return 0;
 
-	*p_before = atoi(q);
-	*p_after = atoi(r);
 	return 1;
 }
 

builtin/prune-packed.c

@@ -3,7 +3,7 @@
 #include "prune-packed.h"
 
 static const char * const prune_packed_usage[] = {
-	N_("git prune-packed [-n | --dry-run] [-q | --quiet]"),
+	"git prune-packed [-n | --dry-run] [-q | --quiet]",
 	NULL
 };
 

builtin/pull.c

@@ -42,9 +42,9 @@ static enum rebase_type parse_config_rebase(const char *key, const char *value,
 		return v;
 
 	if (fatal)
-		die(_("Invalid value for %s: %s"), key, value);
+		die(_("invalid value for '%s': '%s'"), key, value);
 	else
-		error(_("Invalid value for %s: %s"), key, value);
+		error(_("invalid value for '%s': '%s'"), key, value);
 
 	return REBASE_INVALID;
 }
@@ -318,7 +318,7 @@ static const char *config_get_ff(void)
 	if (!strcmp(value, "only"))
 		return "--ff-only";
 
-	die(_("Invalid value for pull.ff: %s"), value);
+	die(_("invalid value for '%s': '%s'"), "pull.ff", value);
 }
 
 /**
@@ -994,8 +994,10 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 		set_reflog_message(argc, argv);
 
 	git_config(git_pull_config, NULL);
-	prepare_repo_settings(the_repository);
-	the_repository->settings.command_requires_full_index = 0;
+	if (the_repository->gitdir) {
+		prepare_repo_settings(the_repository);
+		the_repository->settings.command_requires_full_index = 0;
+	}
 
 	argc = parse_options(argc, argv, prefix, pull_options, pull_usage, 0);
 

builtin/push.c

@@ -486,7 +486,7 @@ static int git_push_config(const char *k, const char *v, void *cb)
 				if (value && !strcasecmp(value, "if-asked"))
 					set_push_cert_flags(flags, SEND_PACK_PUSH_CERT_IF_ASKED);
 				else
-					return error("Invalid value for '%s'", k);
+					return error(_("invalid value for '%s'"), k);
 			}
 		}
 	} else if (!strcmp(k, "push.recursesubmodules")) {

builtin/rebase.c

@@ -37,7 +37,7 @@ static char const * const builtin_rebase_usage[] = {
 		"[--onto <newbase> | --keep-base] [<upstream> [<branch>]]"),
 	N_("git rebase [-i] [options] [--exec <cmd>] [--onto <newbase>] "
 		"--root [<branch>]"),
-	N_("git rebase --continue | --abort | --skip | --edit-todo"),
+	"git rebase --continue | --abort | --skip | --edit-todo",
 	NULL
 };
 
@@ -571,7 +571,8 @@ static int finish_rebase(struct rebase_options *opts)
 
 static int move_to_original_branch(struct rebase_options *opts)
 {
-	struct strbuf orig_head_reflog = STRBUF_INIT, head_reflog = STRBUF_INIT;
+	struct strbuf branch_reflog = STRBUF_INIT, head_reflog = STRBUF_INIT;
+	struct reset_head_opts ropts = { 0 };
 	int ret;
 
 	if (!opts->head_name)
@@ -580,16 +581,17 @@ static int move_to_original_branch(struct rebase_options *opts)
 	if (!opts->onto)
 		BUG("move_to_original_branch without onto");
 
-	strbuf_addf(&orig_head_reflog, "rebase finished: %s onto %s",
+	strbuf_addf(&branch_reflog, "rebase finished: %s onto %s",
 		    opts->head_name, oid_to_hex(&opts->onto->object.oid));
 	strbuf_addf(&head_reflog, "rebase finished: returning to %s",
 		    opts->head_name);
-	ret = reset_head(the_repository, NULL, "", opts->head_name,
-			 RESET_HEAD_REFS_ONLY,
-			 orig_head_reflog.buf, head_reflog.buf,
-			 DEFAULT_REFLOG_ACTION);
+	ropts.branch = opts->head_name;
+	ropts.flags = RESET_HEAD_REFS_ONLY;
+	ropts.branch_msg = branch_reflog.buf;
+	ropts.head_msg = head_reflog.buf;
+	ret = reset_head(the_repository, &ropts);
 
-	strbuf_release(&orig_head_reflog);
+	strbuf_release(&branch_reflog);
 	strbuf_release(&head_reflog);
 	return ret;
 }
@@ -671,13 +673,15 @@ static int run_am(struct rebase_options *opts)
 
 	status = run_command(&format_patch);
 	if (status) {
+		struct reset_head_opts ropts = { 0 };
 		unlink(rebased_patches);
 		free(rebased_patches);
 		strvec_clear(&am.args);
 
-		reset_head(the_repository, &opts->orig_head, "checkout",
-			   opts->head_name, 0,
-			   "HEAD", NULL, DEFAULT_REFLOG_ACTION);
+		ropts.oid = &opts->orig_head;
+		ropts.branch = opts->head_name;
+		ropts.default_reflog_action = DEFAULT_REFLOG_ACTION;
+		reset_head(the_repository, &ropts);
 		error(_("\ngit encountered an error while preparing the "
 			"patches to replay\n"
 			"these revisions:\n"
@@ -813,6 +817,26 @@ static int rebase_config(const char *var, const char *value, void *data)
 	return git_default_config(var, value, data);
 }
 
+static int checkout_up_to_date(struct rebase_options *options)
+{
+	struct strbuf buf = STRBUF_INIT;
+	struct reset_head_opts ropts = { 0 };
+	int ret = 0;
+
+	strbuf_addf(&buf, "%s: checkout %s",
+		    getenv(GIT_REFLOG_ACTION_ENVIRONMENT),
+		    options->switch_to);
+	ropts.oid = &options->orig_head;
+	ropts.branch = options->head_name;
+	ropts.flags = RESET_HEAD_RUN_POST_CHECKOUT_HOOK;
+	ropts.head_msg = buf.buf;
+	if (reset_head(the_repository, &ropts) < 0)
+		ret = error(_("could not switch to %s"), options->switch_to);
+	strbuf_release(&buf);
+
+	return ret;
+}
+
 /*
  * Determines whether the commits in from..to are linear, i.e. contain
  * no merge commits. This function *expects* `from` to be an ancestor of
@@ -1018,6 +1042,7 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 	int reschedule_failed_exec = -1;
 	int allow_preemptive_ff = 1;
 	int preserve_merges_selected = 0;
+	struct reset_head_opts ropts = { 0 };
 	struct option builtin_rebase_options[] = {
 		OPT_STRING(0, "onto", &options.onto_name,
 			   N_("revision"),
@@ -1255,9 +1280,8 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 
 		rerere_clear(the_repository, &merge_rr);
 		string_list_clear(&merge_rr, 1);
-
-		if (reset_head(the_repository, NULL, "reset", NULL, RESET_HEAD_HARD,
-			       NULL, NULL, DEFAULT_REFLOG_ACTION) < 0)
+		ropts.flags = RESET_HEAD_HARD;
+		if (reset_head(the_repository, &ropts) < 0)
 			die(_("could not discard worktree changes"));
 		remove_branch_state(the_repository, 0);
 		if (read_basic_state(&options))
@@ -1274,9 +1298,11 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 
 		if (read_basic_state(&options))
 			exit(1);
-		if (reset_head(the_repository, &options.orig_head, "reset",
-			       options.head_name, RESET_HEAD_HARD,
-			       NULL, NULL, DEFAULT_REFLOG_ACTION) < 0)
+		ropts.oid = &options.orig_head;
+		ropts.branch = options.head_name;
+		ropts.flags = RESET_HEAD_HARD;
+		ropts.default_reflog_action = DEFAULT_REFLOG_ACTION;
+		if (reset_head(the_repository, &ropts) < 0)
 			die(_("could not move back to %s"),
 			    oid_to_hex(&options.orig_head));
 		remove_branch_state(the_repository, 0);
@@ -1642,10 +1668,10 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 	if (repo_read_index(the_repository) < 0)
 		die(_("could not read index"));
 
-	if (options.autostash) {
-		create_autostash(the_repository, state_dir_path("autostash", &options),
-				 DEFAULT_REFLOG_ACTION);
-	}
+	if (options.autostash)
+		create_autostash(the_repository,
+				 state_dir_path("autostash", &options));
+
 
 	if (require_clean_work_tree(the_repository, "rebase",
 				    _("Please commit or stash them."), 1, 1)) {
@@ -1674,21 +1700,9 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		if (!(options.flags & REBASE_FORCE)) {
 			/* Lazily switch to the target branch if needed... */
 			if (options.switch_to) {
-				strbuf_reset(&buf);
-				strbuf_addf(&buf, "%s: checkout %s",
-					    getenv(GIT_REFLOG_ACTION_ENVIRONMENT),
-					    options.switch_to);
-				if (reset_head(the_repository,
-					       &options.orig_head, "checkout",
-					       options.head_name,
-					       RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
-					       NULL, buf.buf,
-					       DEFAULT_REFLOG_ACTION) < 0) {
-					ret = error(_("could not switch to "
-							"%s"),
-						      options.switch_to);
+				ret = checkout_up_to_date(&options);
+				if (ret)
 					goto cleanup;
-				}
 			}
 
 			if (!(options.flags & REBASE_NO_QUIET))
@@ -1755,10 +1769,13 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 
 	strbuf_addf(&msg, "%s: checkout %s",
 		    getenv(GIT_REFLOG_ACTION_ENVIRONMENT), options.onto_name);
-	if (reset_head(the_repository, &options.onto->object.oid, "checkout", NULL,
-		       RESET_HEAD_DETACH | RESET_ORIG_HEAD |
-		       RESET_HEAD_RUN_POST_CHECKOUT_HOOK,
-		       NULL, msg.buf, DEFAULT_REFLOG_ACTION))
+	ropts.oid = &options.onto->object.oid;
+	ropts.orig_head = &options.orig_head,
+	ropts.flags = RESET_HEAD_DETACH | RESET_ORIG_HEAD |
+			RESET_HEAD_RUN_POST_CHECKOUT_HOOK;
+	ropts.head_msg = msg.buf;
+	ropts.default_reflog_action = DEFAULT_REFLOG_ACTION;
+	if (reset_head(the_repository, &ropts))
 		die(_("Could not detach HEAD"));
 	strbuf_release(&msg);
 
@@ -1773,9 +1790,11 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		strbuf_addf(&msg, "rebase finished: %s onto %s",
 			options.head_name ? options.head_name : "detached HEAD",
 			oid_to_hex(&options.onto->object.oid));
-		reset_head(the_repository, NULL, "Fast-forwarded", options.head_name,
-			   RESET_HEAD_REFS_ONLY, "HEAD", msg.buf,
-			   DEFAULT_REFLOG_ACTION);
+		memset(&ropts, 0, sizeof(ropts));
+		ropts.branch = options.head_name;
+		ropts.flags = RESET_HEAD_REFS_ONLY;
+		ropts.head_msg = msg.buf;
+		reset_head(the_repository, &ropts);
 		strbuf_release(&msg);
 		ret = finish_rebase(&options);
 		goto cleanup;

builtin/receive-pack.c

@@ -1961,6 +1961,15 @@ static void execute_commands(struct command *commands,
 		return;
 	}
 
+	/*
+	 * If there is no command ready to run, should return directly to destroy
+	 * temporary data in the quarantine area.
+	 */
+	for (cmd = commands; cmd && cmd->error_string; cmd = cmd->next)
+		; /* nothing */
+	if (!cmd)
+		return;
+
 	/*
 	 * Now we'll start writing out refs, which means the objects need
 	 * to be in their final positions so that other processes can see them.

builtin/reflog.c

@@ -818,7 +818,7 @@ static int cmd_reflog_exists(int argc, const char **argv, const char *prefix)
  */
 
 static const char reflog_usage[] =
-N_("git reflog [ show | expire | delete | exists ]");
+"git reflog [ show | expire | delete | exists ]";
 
 int cmd_reflog(int argc, const char **argv, const char *prefix)
 {

builtin/remote.c

@@ -14,7 +14,7 @@
 #include "commit-reach.h"
 
 static const char * const builtin_remote_usage[] = {
-	N_("git remote [-v | --verbose]"),
+	"git remote [-v | --verbose]",
 	N_("git remote add [-t <branch>] [-m <master>] [-f] [--tags | --no-tags] [--mirror=<fetch|push>] <name> <url>"),
 	N_("git remote rename <old> <new>"),
 	N_("git remote remove <name>"),

builtin/replace.c

@@ -22,7 +22,7 @@ static const char * const git_replace_usage[] = {
 	N_("git replace [-f] <object> <replacement>"),
 	N_("git replace [-f] --edit <object>"),
 	N_("git replace [-f] --graft <commit> [<parent>...]"),
-	N_("git replace [-f] --convert-graft-file"),
+	"git replace [-f] --convert-graft-file",
 	N_("git replace -d <object>..."),
 	N_("git replace [--format=<format>] [-l [<pattern>]]"),
 	NULL

builtin/reset.c

@@ -204,10 +204,16 @@ static int pathspec_needs_expanded_index(const struct pathspec *pathspec)
 			/*
 			 * Special case: if the pattern is a path inside the cone
 			 * followed by only wildcards, the pattern cannot match
-			 * partial sparse directories, so we don't expand the index.
+			 * partial sparse directories, so we know we don't need to
+			 * expand the index.
+			 *
+			 * Examples:
+			 * - in-cone/foo***: doesn't need expanded index
+			 * - not-in-cone/bar*: may need expanded index
+			 * - **.c: may need expanded index
 			 */
-			if (path_in_cone_mode_sparse_checkout(item.original, &the_index) &&
-			    strspn(item.original + item.nowildcard_len, "*") == item.len - item.nowildcard_len)
+			if (strspn(item.original + item.nowildcard_len, "*") == item.len - item.nowildcard_len &&
+			    path_in_cone_mode_sparse_checkout(item.original, &the_index))
 				continue;
 
 			for (pos = 0; pos < active_nr; pos++) {
@@ -274,7 +280,6 @@ static int read_from_tree(const struct pathspec *pathspec,
 		return 1;
 	diffcore_std(&opt);
 	diff_flush(&opt);
-	clear_pathspec(&opt.pathspec);
 
 	return 0;
 }

builtin/rev-list.c

@@ -20,7 +20,7 @@
 #include "packfile.h"
 
 static const char rev_list_usage[] =
-"git rev-list [OPTION] <commit-id>... [ -- paths... ]\n"
+"git rev-list [<options>] <commit-id>... [-- <path>...]\n"
 "  limiting output:\n"
 "    --max-count=<n>\n"
 "    --max-age=<epoch>\n"

builtin/send-pack.c

@@ -145,7 +145,7 @@ static int send_pack_config(const char *k, const char *v, void *cb)
 				if (value && !strcasecmp(value, "if-asked"))
 					args.push_cert = SEND_PACK_PUSH_CERT_IF_ASKED;
 				else
-					return error("Invalid value for '%s'", k);
+					return error(_("invalid value for '%s'"), k);
 			}
 		}
 	}

builtin/shortlog.c

@@ -388,6 +388,7 @@ int cmd_shortlog(int argc, const char **argv, const char *prefix)
 		parse_revision_opt(&rev, &ctx, options, shortlog_usage);
 	}
 parse_done:
+	revision_opts_finish(&rev);
 	argc = parse_options_end(&ctx);
 
 	if (nongit && argc > 1) {

builtin/show-branch.c

@@ -8,6 +8,7 @@
 #include "parse-options.h"
 #include "dir.h"
 #include "commit-slab.h"
+#include "date.h"
 
 static const char* show_branch_usage[] = {
     N_("git show-branch [-a | --all] [-r | --remotes] [--topo-order | --date-order]\n"

builtin/sparse-checkout.c

@@ -15,6 +15,7 @@
 #include "wt-status.h"
 #include "quote.h"
 #include "sparse-index.h"
+#include "worktree.h"
 
 static const char *empty_base = "";
 
@@ -43,7 +44,7 @@ static void write_patterns_to_file(FILE *fp, struct pattern_list *pl)
 }
 
 static char const * const builtin_sparse_checkout_list_usage[] = {
-	N_("git sparse-checkout list"),
+	"git sparse-checkout list",
 	NULL
 };
 
@@ -361,26 +362,23 @@ enum sparse_checkout_mode {
 
 static int set_config(enum sparse_checkout_mode mode)
 {
-	const char *config_path;
-
-	if (upgrade_repository_format(1) < 0)
-		die(_("unable to upgrade repository format to enable worktreeConfig"));
-	if (git_config_set_gently("extensions.worktreeConfig", "true")) {
-		error(_("failed to set extensions.worktreeConfig setting"));
+	/* Update to use worktree config, if not already. */
+	if (init_worktree_config(the_repository)) {
+		error(_("failed to initialize worktree config"));
 		return 1;
 	}
 
-	config_path = git_path("config.worktree");
-	git_config_set_in_file_gently(config_path,
-				      "core.sparseCheckout",
-				      mode ? "true" : NULL);
-
-	git_config_set_in_file_gently(config_path,
-				      "core.sparseCheckoutCone",
-				      mode == MODE_CONE_PATTERNS ? "true" : NULL);
+	if (repo_config_set_worktree_gently(the_repository,
+					    "core.sparseCheckout",
+					    mode ? "true" : "false") ||
+	    repo_config_set_worktree_gently(the_repository,
+					    "core.sparseCheckoutCone",
+					    mode == MODE_CONE_PATTERNS ?
+						"true" : "false"))
+		return 1;
 
 	if (mode == MODE_NO_PATTERNS)
-		set_sparse_index_config(the_repository, 0);
+		return set_sparse_index_config(the_repository, 0);
 
 	return 0;
 }
@@ -421,7 +419,7 @@ static int update_modes(int *cone_mode, int *sparse_index)
 }
 
 static char const * const builtin_sparse_checkout_init_usage[] = {
-	N_("git sparse-checkout init [--cone] [--[no-]sparse-index]"),
+	"git sparse-checkout init [--cone] [--[no-]sparse-index]",
 	NULL
 };
 
@@ -767,7 +765,7 @@ static int sparse_checkout_set(int argc, const char **argv, const char *prefix)
 }
 
 static char const * const builtin_sparse_checkout_reapply_usage[] = {
-	N_("git sparse-checkout reapply [--[no-]cone] [--[no-]sparse-index]"),
+	"git sparse-checkout reapply [--[no-]cone] [--[no-]sparse-index]",
 	NULL
 };
 
@@ -805,7 +803,7 @@ static int sparse_checkout_reapply(int argc, const char **argv)
 }
 
 static char const * const builtin_sparse_checkout_disable_usage[] = {
-	N_("git sparse-checkout disable"),
+	"git sparse-checkout disable",
 	NULL
 };
 

builtin/stripspace.c

@@ -15,8 +15,8 @@ static void comment_lines(struct strbuf *buf)
 }
 
 static const char * const stripspace_usage[] = {
-	N_("git stripspace [-s | --strip-comments]"),
-	N_("git stripspace [-c | --comment-lines]"),
+	"git stripspace [-s | --strip-comments]",
+	"git stripspace [-c | --comment-lines]",
 	NULL
 };
 

builtin/submodule--helper.c

@@ -20,6 +20,8 @@
 #include "diff.h"
 #include "object-store.h"
 #include "advice.h"
+#include "branch.h"
+#include "list-objects-filter-options.h"
 
 #define OPT_QUIET (1 << 0)
 #define OPT_CACHED (1 << 1)
@@ -1630,6 +1632,7 @@ struct module_clone_data {
 	const char *name;
 	const char *url;
 	const char *depth;
+	struct list_objects_filter_options *filter_options;
 	struct string_list reference;
 	unsigned int quiet: 1;
 	unsigned int progress: 1;
@@ -1796,6 +1799,10 @@ static int clone_submodule(struct module_clone_data *clone_data)
 			strvec_push(&cp.args, "--dissociate");
 		if (sm_gitdir && *sm_gitdir)
 			strvec_pushl(&cp.args, "--separate-git-dir", sm_gitdir, NULL);
+		if (clone_data->filter_options && clone_data->filter_options->choice)
+			strvec_pushf(&cp.args, "--filter=%s",
+				     expand_list_objects_filter_spec(
+					     clone_data->filter_options));
 		if (clone_data->single_branch >= 0)
 			strvec_push(&cp.args, clone_data->single_branch ?
 				    "--single-branch" :
@@ -1852,6 +1859,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 {
 	int dissociate = 0, quiet = 0, progress = 0, require_init = 0;
 	struct module_clone_data clone_data = MODULE_CLONE_DATA_INIT;
+	struct list_objects_filter_options filter_options;
 
 	struct option module_clone_options[] = {
 		OPT_STRING(0, "prefix", &clone_data.prefix,
@@ -1881,17 +1889,19 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 			   N_("disallow cloning into non-empty directory")),
 		OPT_BOOL(0, "single-branch", &clone_data.single_branch,
 			 N_("clone only one branch, HEAD or --branch")),
+		OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
 		OPT_END()
 	};
 
 	const char *const git_submodule_helper_usage[] = {
 		N_("git submodule--helper clone [--prefix=<path>] [--quiet] "
 		   "[--reference <repository>] [--name <name>] [--depth <depth>] "
-		   "[--single-branch] "
+		   "[--single-branch] [--filter <filter-spec>]"
 		   "--url <url> --path <path>"),
 		NULL
 	};
 
+	memset(&filter_options, 0, sizeof(filter_options));
 	argc = parse_options(argc, argv, prefix, module_clone_options,
 			     git_submodule_helper_usage, 0);
 
@@ -1899,12 +1909,14 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	clone_data.quiet = !!quiet;
 	clone_data.progress = !!progress;
 	clone_data.require_init = !!require_init;
+	clone_data.filter_options = &filter_options;
 
 	if (argc || !clone_data.url || !clone_data.path || !*(clone_data.path))
 		usage_with_options(git_submodule_helper_usage,
 				   module_clone_options);
 
 	clone_submodule(&clone_data);
+	list_objects_filter_release(&filter_options);
 	return 0;
 }
 
@@ -1994,6 +2006,7 @@ struct submodule_update_clone {
 	const char *recursive_prefix;
 	const char *prefix;
 	int single_branch;
+	struct list_objects_filter_options *filter_options;
 
 	/* to be consumed by git-submodule.sh */
 	struct update_clone_data *update_clone;
@@ -2154,6 +2167,9 @@ static int prepare_to_clone_next_submodule(const struct cache_entry *ce,
 		strvec_pushl(&child->args, "--prefix", suc->prefix, NULL);
 	if (suc->recommend_shallow && sub->recommend_shallow == 1)
 		strvec_push(&child->args, "--depth=1");
+	if (suc->filter_options && suc->filter_options->choice)
+		strvec_pushf(&child->args, "--filter=%s",
+			     expand_list_objects_filter_spec(suc->filter_options));
 	if (suc->require_init)
 		strvec_push(&child->args, "--require-init");
 	strvec_pushl(&child->args, "--path", sub->path, NULL);
@@ -2498,6 +2514,8 @@ static int update_clone(int argc, const char **argv, const char *prefix)
 	const char *update = NULL;
 	struct pathspec pathspec;
 	struct submodule_update_clone suc = SUBMODULE_UPDATE_CLONE_INIT;
+	struct list_objects_filter_options filter_options;
+	int ret;
 
 	struct option module_update_clone_options[] = {
 		OPT_STRING(0, "prefix", &prefix,
@@ -2528,6 +2546,7 @@ static int update_clone(int argc, const char **argv, const char *prefix)
 			   N_("disallow cloning into non-empty directory")),
 		OPT_BOOL(0, "single-branch", &suc.single_branch,
 			 N_("clone only one branch, HEAD or --branch")),
+		OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
 		OPT_END()
 	};
 
@@ -2540,20 +2559,26 @@ static int update_clone(int argc, const char **argv, const char *prefix)
 	update_clone_config_from_gitmodules(&suc.max_jobs);
 	git_config(git_update_clone_config, &suc.max_jobs);
 
+	memset(&filter_options, 0, sizeof(filter_options));
 	argc = parse_options(argc, argv, prefix, module_update_clone_options,
 			     git_submodule_helper_usage, 0);
+	suc.filter_options = &filter_options;
 
 	if (update)
 		if (parse_submodule_update_strategy(update, &suc.update) < 0)
 			die(_("bad value for update parameter"));
 
-	if (module_list_compute(argc, argv, prefix, &pathspec, &suc.list) < 0)
+	if (module_list_compute(argc, argv, prefix, &pathspec, &suc.list) < 0) {
+		list_objects_filter_release(&filter_options);
 		return 1;
+	}
 
 	if (pathspec.nr)
 		suc.warn_if_uninitialized = 1;
 
-	return update_submodules(&suc);
+	ret = update_submodules(&suc);
+	list_objects_filter_release(&filter_options);
+	return ret;
 }
 
 static int run_update_procedure(int argc, const char **argv, const char *prefix)
@@ -2883,7 +2908,7 @@ static int module_config(int argc, const char **argv, const char *prefix)
 	const char *const git_submodule_helper_usage[] = {
 		N_("git submodule--helper config <name> [<value>]"),
 		N_("git submodule--helper config --unset <name>"),
-		N_("git submodule--helper config --check-writeable"),
+		"git submodule--helper config --check-writeable",
 		NULL
 	};
 
@@ -2984,6 +3009,42 @@ static int module_set_branch(int argc, const char **argv, const char *prefix)
 	return !!ret;
 }
 
+static int module_create_branch(int argc, const char **argv, const char *prefix)
+{
+	enum branch_track track;
+	int quiet = 0, force = 0, reflog = 0, dry_run = 0;
+
+	struct option options[] = {
+		OPT__QUIET(&quiet, N_("print only error messages")),
+		OPT__FORCE(&force, N_("force creation"), 0),
+		OPT_BOOL(0, "create-reflog", &reflog,
+			 N_("create the branch's reflog")),
+		OPT_SET_INT('t', "track", &track,
+			    N_("set up tracking mode (see git-pull(1))"),
+			    BRANCH_TRACK_EXPLICIT),
+		OPT__DRY_RUN(&dry_run,
+			     N_("show whether the branch would be created")),
+		OPT_END()
+	};
+	const char *const usage[] = {
+		N_("git submodule--helper create-branch [-f|--force] [--create-reflog] [-q|--quiet] [-t|--track] [-n|--dry-run] <name> <start_oid> <start_name>"),
+		NULL
+	};
+
+	git_config(git_default_config, NULL);
+	track = git_branch_track;
+	argc = parse_options(argc, argv, prefix, options, usage, 0);
+
+	if (argc != 3)
+		usage_with_options(usage, options);
+
+	if (!quiet && !dry_run)
+		printf_ln(_("creating branch '%s'"), argv[0]);
+
+	create_branches_recursively(the_repository, argv[0], argv[1], argv[2],
+				    force, reflog, quiet, track, dry_run);
+	return 0;
+}
 struct add_data {
 	const char *prefix;
 	const char *branch;
@@ -3390,6 +3451,7 @@ static struct cmd_struct commands[] = {
 	{"config", module_config, 0},
 	{"set-url", module_set_url, 0},
 	{"set-branch", module_set_branch, 0},
+	{"create-branch", module_create_branch, 0},
 };
 
 int cmd_submodule__helper(int argc, const char **argv, const char *prefix)

builtin/tag.c

@@ -20,6 +20,7 @@
 #include "oid-array.h"
 #include "column.h"
 #include "ref-filter.h"
+#include "date.h"
 
 static const char * const git_tag_usage[] = {
 	N_("git tag [-a | -s | -u <key-id>] [-f] [-m <msg> | -F <file>]\n"

builtin/update-index.c

@@ -606,7 +606,7 @@ static struct cache_entry *read_one_ent(const char *which,
 			error("%s: not in %s branch.", path, which);
 		return NULL;
 	}
-	if (mode == S_IFDIR) {
+	if (!the_index.sparse_index && mode == S_IFDIR) {
 		if (which)
 			error("%s: not a blob in %s branch.", path, which);
 		return NULL;
@@ -743,8 +743,6 @@ static int do_reupdate(int ac, const char **av,
 		 */
 		has_head = 0;
  redo:
-	/* TODO: audit for interaction with sparse-index. */
-	ensure_full_index(&the_index);
 	for (pos = 0; pos < active_nr; pos++) {
 		const struct cache_entry *ce = active_cache[pos];
 		struct cache_entry *old = NULL;
@@ -761,6 +759,16 @@ static int do_reupdate(int ac, const char **av,
 			discard_cache_entry(old);
 			continue; /* unchanged */
 		}
+
+		/* At this point, we know the contents of the sparse directory are
+		 * modified with respect to HEAD, so we expand the index and restart
+		 * to process each path individually
+		 */
+		if (S_ISSPARSEDIR(ce->ce_mode)) {
+			ensure_full_index(&the_index);
+			goto redo;
+		}
+
 		/* Be careful.  The working tree may not have the
 		 * path anymore, in which case, under 'allow_remove',
 		 * or worse yet 'allow_replace', active_nr may decrease.
@@ -1088,6 +1096,9 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 
 	git_config(git_default_config, NULL);
 
+	prepare_repo_settings(r);
+	the_repository->settings.command_requires_full_index = 0;
+
 	/* we will diagnose later if it turns out that we need to update it */
 	newfd = hold_locked_index(&lock_file, 0);
 	if (newfd < 0)
@@ -1225,14 +1236,17 @@ int cmd_update_index(int argc, const char **argv, const char *prefix)
 	}
 
 	if (fsmonitor > 0) {
-		if (git_config_get_fsmonitor() == 0)
+		enum fsmonitor_mode fsm_mode = fsm_settings__get_mode(r);
+		if (fsm_mode == FSMONITOR_MODE_DISABLED) {
 			warning(_("core.fsmonitor is unset; "
 				"set it if you really want to "
 				"enable fsmonitor"));
+		}
 		add_fsmonitor(&the_index);
 		report(_("fsmonitor enabled"));
 	} else if (!fsmonitor) {
-		if (git_config_get_fsmonitor() == 1)
+		enum fsmonitor_mode fsm_mode = fsm_settings__get_mode(r);
+		if (fsm_mode > FSMONITOR_MODE_DISABLED)
 			warning(_("core.fsmonitor is set; "
 				"remove it if you really want to "
 				"disable fsmonitor"));

builtin/update-server-info.c

@@ -4,7 +4,7 @@
 #include "parse-options.h"
 
 static const char * const update_server_info_usage[] = {
-	N_("git update-server-info [--force]"),
+	"git update-server-info [--force]",
 	NULL
 };
 

builtin/worktree.c

@@ -335,6 +335,69 @@ static int add_worktree(const char *path, const char *refname,
 	strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
 	write_file(sb.buf, "../..");
 
+	/*
+	 * If the current worktree has sparse-checkout enabled, then copy
+	 * the sparse-checkout patterns from the current worktree.
+	 */
+	if (core_apply_sparse_checkout) {
+		char *from_file = git_pathdup("info/sparse-checkout");
+		char *to_file = xstrfmt("%s/info/sparse-checkout",
+					sb_repo.buf);
+
+		if (file_exists(from_file)) {
+			if (safe_create_leading_directories(to_file) ||
+			    copy_file(to_file, from_file, 0666))
+				error(_("failed to copy '%s' to '%s'; sparse-checkout may not work correctly"),
+				      from_file, to_file);
+		}
+
+		free(from_file);
+		free(to_file);
+	}
+
+	/*
+	 * If we are using worktree config, then copy all current config
+	 * values from the current worktree into the new one, that way the
+	 * new worktree behaves the same as this one.
+	 */
+	if (repository_format_worktree_config) {
+		char *from_file = git_pathdup("config.worktree");
+		char *to_file = xstrfmt("%s/config.worktree",
+					sb_repo.buf);
+
+		if (file_exists(from_file)) {
+			struct config_set cs = { { 0 } };
+			const char *core_worktree;
+			int bare;
+
+			if (safe_create_leading_directories(to_file) ||
+			    copy_file(to_file, from_file, 0666)) {
+				error(_("failed to copy worktree config from '%s' to '%s'"),
+				      from_file, to_file);
+				goto worktree_copy_cleanup;
+			}
+
+			git_configset_init(&cs);
+			git_configset_add_file(&cs, from_file);
+
+			if (!git_configset_get_bool(&cs, "core.bare", &bare) &&
+			    bare &&
+			    git_config_set_multivar_in_file_gently(
+					to_file, "core.bare", NULL, "true", 0))
+				error(_("failed to unset 'core.bare' in '%s'"), to_file);
+			if (!git_configset_get_value(&cs, "core.worktree", &core_worktree) &&
+			    git_config_set_in_file_gently(to_file,
+							  "core.worktree", NULL))
+				error(_("failed to unset 'core.worktree' in '%s'"), to_file);
+
+			git_configset_clear(&cs);
+		}
+
+worktree_copy_cleanup:
+		free(from_file);
+		free(to_file);
+	}
+
 	strvec_pushf(&child_env, "%s=%s", GIT_DIR_ENVIRONMENT, sb_git.buf);
 	strvec_pushf(&child_env, "%s=%s", GIT_WORK_TREE_ENVIRONMENT, path);
 	cp.git_cmd = 1;

cache.h

@@ -999,7 +999,6 @@ extern int core_preload_index;
 extern int precomposed_unicode;
 extern int protect_hfs;
 extern int protect_ntfs;
-extern const char *core_fsmonitor;
 
 extern int core_apply_sparse_checkout;
 extern int core_sparse_checkout_cone;
@@ -1558,48 +1557,6 @@ struct object *repo_peel_to_type(struct repository *r,
 #define peel_to_type(name, namelen, obj, type) \
 	repo_peel_to_type(the_repository, name, namelen, obj, type)
 
-enum date_mode_type {
-	DATE_NORMAL = 0,
-	DATE_HUMAN,
-	DATE_RELATIVE,
-	DATE_SHORT,
-	DATE_ISO8601,
-	DATE_ISO8601_STRICT,
-	DATE_RFC2822,
-	DATE_STRFTIME,
-	DATE_RAW,
-	DATE_UNIX
-};
-
-struct date_mode {
-	enum date_mode_type type;
-	const char *strftime_fmt;
-	int local;
-};
-
-/*
- * Convenience helper for passing a constant type, like:
- *
- *   show_date(t, tz, DATE_MODE(NORMAL));
- */
-#define DATE_MODE(t) date_mode_from_type(DATE_##t)
-struct date_mode *date_mode_from_type(enum date_mode_type type);
-
-const char *show_date(timestamp_t time, int timezone, const struct date_mode *mode);
-void show_date_relative(timestamp_t time, struct strbuf *timebuf);
-void show_date_human(timestamp_t time, int tz, const struct timeval *now,
-			struct strbuf *timebuf);
-int parse_date(const char *date, struct strbuf *out);
-int parse_date_basic(const char *date, timestamp_t *timestamp, int *offset);
-int parse_expiry_date(const char *date, timestamp_t *timestamp);
-void datestamp(struct strbuf *out);
-#define approxidate(s) approxidate_careful((s), NULL)
-timestamp_t approxidate_careful(const char *, int *);
-timestamp_t approxidate_relative(const char *date);
-void parse_date_format(const char *format, struct date_mode *mode);
-int date_overflows(timestamp_t date);
-time_t tm_to_time_t(const struct tm *tm);
-
 #define IDENT_STRICT	       1
 #define IDENT_NO_DATE	       2
 #define IDENT_NO_NAME	       4
@@ -1645,14 +1602,6 @@ struct ident_split {
  */
 int split_ident_line(struct ident_split *, const char *, int);
 
-/*
- * Like show_date, but pull the timestamp and tz parameters from
- * the ident_split. It will also sanity-check the values and produce
- * a well-known sentinel date if they appear bogus.
- */
-const char *show_ident_date(const struct ident_split *id,
-			    const struct date_mode *mode);
-
 /*
  * Compare split idents for equality or strict ordering. Note that we
  * compare only the ident part of the line, ignoring any timestamp.

compat/fsmonitor/fsm-darwin-gcc.h

@@ -0,0 +1,92 @@
+#ifndef FSM_DARWIN_GCC_H
+#define FSM_DARWIN_GCC_H
+
+#ifndef __clang__
+/*
+ * It is possible to #include CoreFoundation/CoreFoundation.h when compiling
+ * with clang, but not with GCC as of time of writing.
+ *
+ * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93082 for details.
+ */
+typedef unsigned int FSEventStreamCreateFlags;
+#define kFSEventStreamEventFlagNone               0x00000000
+#define kFSEventStreamEventFlagMustScanSubDirs    0x00000001
+#define kFSEventStreamEventFlagUserDropped        0x00000002
+#define kFSEventStreamEventFlagKernelDropped      0x00000004
+#define kFSEventStreamEventFlagEventIdsWrapped    0x00000008
+#define kFSEventStreamEventFlagHistoryDone        0x00000010
+#define kFSEventStreamEventFlagRootChanged        0x00000020
+#define kFSEventStreamEventFlagMount              0x00000040
+#define kFSEventStreamEventFlagUnmount            0x00000080
+#define kFSEventStreamEventFlagItemCreated        0x00000100
+#define kFSEventStreamEventFlagItemRemoved        0x00000200
+#define kFSEventStreamEventFlagItemInodeMetaMod   0x00000400
+#define kFSEventStreamEventFlagItemRenamed        0x00000800
+#define kFSEventStreamEventFlagItemModified       0x00001000
+#define kFSEventStreamEventFlagItemFinderInfoMod  0x00002000
+#define kFSEventStreamEventFlagItemChangeOwner    0x00004000
+#define kFSEventStreamEventFlagItemXattrMod       0x00008000
+#define kFSEventStreamEventFlagItemIsFile         0x00010000
+#define kFSEventStreamEventFlagItemIsDir          0x00020000
+#define kFSEventStreamEventFlagItemIsSymlink      0x00040000
+#define kFSEventStreamEventFlagOwnEvent           0x00080000
+#define kFSEventStreamEventFlagItemIsHardlink     0x00100000
+#define kFSEventStreamEventFlagItemIsLastHardlink 0x00200000
+#define kFSEventStreamEventFlagItemCloned         0x00400000
+
+typedef struct __FSEventStream *FSEventStreamRef;
+typedef const FSEventStreamRef ConstFSEventStreamRef;
+
+typedef unsigned int CFStringEncoding;
+#define kCFStringEncodingUTF8 0x08000100
+
+typedef const struct __CFString *CFStringRef;
+typedef const struct __CFArray *CFArrayRef;
+typedef const struct __CFRunLoop *CFRunLoopRef;
+
+struct FSEventStreamContext {
+    long long version;
+    void *cb_data, *retain, *release, *copy_description;
+};
+
+typedef struct FSEventStreamContext FSEventStreamContext;
+typedef unsigned int FSEventStreamEventFlags;
+#define kFSEventStreamCreateFlagNoDefer 0x02
+#define kFSEventStreamCreateFlagWatchRoot 0x04
+#define kFSEventStreamCreateFlagFileEvents 0x10
+
+typedef unsigned long long FSEventStreamEventId;
+#define kFSEventStreamEventIdSinceNow 0xFFFFFFFFFFFFFFFFULL
+
+typedef void (*FSEventStreamCallback)(ConstFSEventStreamRef streamRef,
+				      void *context,
+				      __SIZE_TYPE__ num_of_events,
+				      void *event_paths,
+				      const FSEventStreamEventFlags event_flags[],
+				      const FSEventStreamEventId event_ids[]);
+typedef double CFTimeInterval;
+FSEventStreamRef FSEventStreamCreate(void *allocator,
+				     FSEventStreamCallback callback,
+				     FSEventStreamContext *context,
+				     CFArrayRef paths_to_watch,
+				     FSEventStreamEventId since_when,
+				     CFTimeInterval latency,
+				     FSEventStreamCreateFlags flags);
+CFStringRef CFStringCreateWithCString(void *allocator, const char *string,
+				      CFStringEncoding encoding);
+CFArrayRef CFArrayCreate(void *allocator, const void **items, long long count,
+			 void *callbacks);
+void CFRunLoopRun(void);
+void CFRunLoopStop(CFRunLoopRef run_loop);
+CFRunLoopRef CFRunLoopGetCurrent(void);
+extern CFStringRef kCFRunLoopDefaultMode;
+void FSEventStreamScheduleWithRunLoop(FSEventStreamRef stream,
+				      CFRunLoopRef run_loop,
+				      CFStringRef run_loop_mode);
+unsigned char FSEventStreamStart(FSEventStreamRef stream);
+void FSEventStreamStop(FSEventStreamRef stream);
+void FSEventStreamInvalidate(FSEventStreamRef stream);
+void FSEventStreamRelease(FSEventStreamRef stream);
+
+#endif /* !clang */
+#endif /* FSM_DARWIN_GCC_H */

compat/fsmonitor/fsm-listen-darwin.c

@@ -0,0 +1,427 @@
+#ifndef __clang__
+#include "fsm-darwin-gcc.h"
+#else
+#include <CoreFoundation/CoreFoundation.h>
+#include <CoreServices/CoreServices.h>
+
+#ifndef AVAILABLE_MAC_OS_X_VERSION_10_13_AND_LATER
+/*
+ * This enum value was added in 10.13 to:
+ *
+ * /Applications/Xcode.app/Contents/Developer/Platforms/ \
+ *    MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/ \
+ *    Library/Frameworks/CoreServices.framework/Frameworks/ \
+ *    FSEvents.framework/Versions/Current/Headers/FSEvents.h
+ *
+ * If we're compiling against an older SDK, this symbol won't be
+ * present.  Silently define it here so that we don't have to ifdef
+ * the logging or masking below.  This should be harmless since older
+ * versions of macOS won't ever emit this FS event anyway.
+ */
+#define kFSEventStreamEventFlagItemCloned         0x00400000
+#endif
+#endif
+
+#include "cache.h"
+#include "fsmonitor.h"
+#include "fsm-listen.h"
+#include "fsmonitor--daemon.h"
+
+struct fsmonitor_daemon_backend_data
+{
+	CFStringRef cfsr_worktree_path;
+	CFStringRef cfsr_gitdir_path;
+
+	CFArrayRef cfar_paths_to_watch;
+	int nr_paths_watching;
+
+	FSEventStreamRef stream;
+
+	CFRunLoopRef rl;
+
+	enum shutdown_style {
+		SHUTDOWN_EVENT = 0,
+		FORCE_SHUTDOWN,
+		FORCE_ERROR_STOP,
+	} shutdown_style;
+
+	unsigned int stream_scheduled:1;
+	unsigned int stream_started:1;
+};
+
+static void log_flags_set(const char *path, const FSEventStreamEventFlags flag)
+{
+	struct strbuf msg = STRBUF_INIT;
+
+	if (flag & kFSEventStreamEventFlagMustScanSubDirs)
+		strbuf_addstr(&msg, "MustScanSubDirs|");
+	if (flag & kFSEventStreamEventFlagUserDropped)
+		strbuf_addstr(&msg, "UserDropped|");
+	if (flag & kFSEventStreamEventFlagKernelDropped)
+		strbuf_addstr(&msg, "KernelDropped|");
+	if (flag & kFSEventStreamEventFlagEventIdsWrapped)
+		strbuf_addstr(&msg, "EventIdsWrapped|");
+	if (flag & kFSEventStreamEventFlagHistoryDone)
+		strbuf_addstr(&msg, "HistoryDone|");
+	if (flag & kFSEventStreamEventFlagRootChanged)
+		strbuf_addstr(&msg, "RootChanged|");
+	if (flag & kFSEventStreamEventFlagMount)
+		strbuf_addstr(&msg, "Mount|");
+	if (flag & kFSEventStreamEventFlagUnmount)
+		strbuf_addstr(&msg, "Unmount|");
+	if (flag & kFSEventStreamEventFlagItemChangeOwner)
+		strbuf_addstr(&msg, "ItemChangeOwner|");
+	if (flag & kFSEventStreamEventFlagItemCreated)
+		strbuf_addstr(&msg, "ItemCreated|");
+	if (flag & kFSEventStreamEventFlagItemFinderInfoMod)
+		strbuf_addstr(&msg, "ItemFinderInfoMod|");
+	if (flag & kFSEventStreamEventFlagItemInodeMetaMod)
+		strbuf_addstr(&msg, "ItemInodeMetaMod|");
+	if (flag & kFSEventStreamEventFlagItemIsDir)
+		strbuf_addstr(&msg, "ItemIsDir|");
+	if (flag & kFSEventStreamEventFlagItemIsFile)
+		strbuf_addstr(&msg, "ItemIsFile|");
+	if (flag & kFSEventStreamEventFlagItemIsHardlink)
+		strbuf_addstr(&msg, "ItemIsHardlink|");
+	if (flag & kFSEventStreamEventFlagItemIsLastHardlink)
+		strbuf_addstr(&msg, "ItemIsLastHardlink|");
+	if (flag & kFSEventStreamEventFlagItemIsSymlink)
+		strbuf_addstr(&msg, "ItemIsSymlink|");
+	if (flag & kFSEventStreamEventFlagItemModified)
+		strbuf_addstr(&msg, "ItemModified|");
+	if (flag & kFSEventStreamEventFlagItemRemoved)
+		strbuf_addstr(&msg, "ItemRemoved|");
+	if (flag & kFSEventStreamEventFlagItemRenamed)
+		strbuf_addstr(&msg, "ItemRenamed|");
+	if (flag & kFSEventStreamEventFlagItemXattrMod)
+		strbuf_addstr(&msg, "ItemXattrMod|");
+	if (flag & kFSEventStreamEventFlagOwnEvent)
+		strbuf_addstr(&msg, "OwnEvent|");
+	if (flag & kFSEventStreamEventFlagItemCloned)
+		strbuf_addstr(&msg, "ItemCloned|");
+
+	trace_printf_key(&trace_fsmonitor, "fsevent: '%s', flags=%u %s",
+			 path, flag, msg.buf);
+
+	strbuf_release(&msg);
+}
+
+static int ef_is_root_delete(const FSEventStreamEventFlags ef)
+{
+	return (ef & kFSEventStreamEventFlagItemIsDir &&
+		ef & kFSEventStreamEventFlagItemRemoved);
+}
+
+static int ef_is_root_renamed(const FSEventStreamEventFlags ef)
+{
+	return (ef & kFSEventStreamEventFlagItemIsDir &&
+		ef & kFSEventStreamEventFlagItemRenamed);
+}
+
+static int ef_is_dropped(const FSEventStreamEventFlags ef)
+{
+	return (ef & kFSEventStreamEventFlagMustScanSubDirs ||
+		ef & kFSEventStreamEventFlagKernelDropped ||
+		ef & kFSEventStreamEventFlagUserDropped);
+}
+
+static void fsevent_callback(ConstFSEventStreamRef streamRef,
+			     void *ctx,
+			     size_t num_of_events,
+			     void *event_paths,
+			     const FSEventStreamEventFlags event_flags[],
+			     const FSEventStreamEventId event_ids[])
+{
+	struct fsmonitor_daemon_state *state = ctx;
+	struct fsmonitor_daemon_backend_data *data = state->backend_data;
+	char **paths = (char **)event_paths;
+	struct fsmonitor_batch *batch = NULL;
+	struct string_list cookie_list = STRING_LIST_INIT_DUP;
+	const char *path_k;
+	const char *slash;
+	int k;
+	struct strbuf tmp = STRBUF_INIT;
+
+	/*
+	 * Build a list of all filesystem changes into a private/local
+	 * list and without holding any locks.
+	 */
+	for (k = 0; k < num_of_events; k++) {
+		/*
+		 * On Mac, we receive an array of absolute paths.
+		 */
+		path_k = paths[k];
+
+		/*
+		 * If you want to debug FSEvents, log them to GIT_TRACE_FSMONITOR.
+		 * Please don't log them to Trace2.
+		 *
+		 * trace_printf_key(&trace_fsmonitor, "Path: '%s'", path_k);
+		 */
+
+		/*
+		 * If event[k] is marked as dropped, we assume that we have
+		 * lost sync with the filesystem and should flush our cached
+		 * data.  We need to:
+		 *
+		 * [1] Abort/wake any client threads waiting for a cookie and
+		 *     flush the cached state data (the current token), and
+		 *     create a new token.
+		 *
+		 * [2] Discard the batch that we were locally building (since
+		 *     they are conceptually relative to the just flushed
+		 *     token).
+		 */
+		if (ef_is_dropped(event_flags[k])) {
+			if (trace_pass_fl(&trace_fsmonitor))
+				log_flags_set(path_k, event_flags[k]);
+
+			fsmonitor_force_resync(state);
+			fsmonitor_batch__free_list(batch);
+			string_list_clear(&cookie_list, 0);
+
+			/*
+			 * We assume that any events that we received
+			 * in this callback after this dropped event
+			 * may still be valid, so we continue rather
+			 * than break.  (And just in case there is a
+			 * delete of ".git" hiding in there.)
+			 */
+			continue;
+		}
+
+		switch (fsmonitor_classify_path_absolute(state, path_k)) {
+
+		case IS_INSIDE_DOT_GIT_WITH_COOKIE_PREFIX:
+		case IS_INSIDE_GITDIR_WITH_COOKIE_PREFIX:
+			/* special case cookie files within .git or gitdir */
+
+			/* Use just the filename of the cookie file. */
+			slash = find_last_dir_sep(path_k);
+			string_list_append(&cookie_list,
+					   slash ? slash + 1 : path_k);
+			break;
+
+		case IS_INSIDE_DOT_GIT:
+		case IS_INSIDE_GITDIR:
+			/* ignore all other paths inside of .git or gitdir */
+			break;
+
+		case IS_DOT_GIT:
+		case IS_GITDIR:
+			/*
+			 * If .git directory is deleted or renamed away,
+			 * we have to quit.
+			 */
+			if (ef_is_root_delete(event_flags[k])) {
+				trace_printf_key(&trace_fsmonitor,
+						 "event: gitdir removed");
+				goto force_shutdown;
+			}
+			if (ef_is_root_renamed(event_flags[k])) {
+				trace_printf_key(&trace_fsmonitor,
+						 "event: gitdir renamed");
+				goto force_shutdown;
+			}
+			break;
+
+		case IS_WORKDIR_PATH:
+			/* try to queue normal pathnames */
+
+			if (trace_pass_fl(&trace_fsmonitor))
+				log_flags_set(path_k, event_flags[k]);
+
+			/*
+			 * Because of the implicit "binning" (the
+			 * kernel calls us at a given frequency) and
+			 * de-duping (the kernel is free to combine
+			 * multiple events for a given pathname), an
+			 * individual fsevent could be marked as both
+			 * a file and directory.  Add it to the queue
+			 * with both spellings so that the client will
+			 * know how much to invalidate/refresh.
+			 */
+
+			if (event_flags[k] & kFSEventStreamEventFlagItemIsFile) {
+				const char *rel = path_k +
+					state->path_worktree_watch.len + 1;
+
+				if (!batch)
+					batch = fsmonitor_batch__new();
+				fsmonitor_batch__add_path(batch, rel);
+			}
+
+			if (event_flags[k] & kFSEventStreamEventFlagItemIsDir) {
+				const char *rel = path_k +
+					state->path_worktree_watch.len + 1;
+
+				strbuf_reset(&tmp);
+				strbuf_addstr(&tmp, rel);
+				strbuf_addch(&tmp, '/');
+
+				if (!batch)
+					batch = fsmonitor_batch__new();
+				fsmonitor_batch__add_path(batch, tmp.buf);
+			}
+
+			break;
+
+		case IS_OUTSIDE_CONE:
+		default:
+			trace_printf_key(&trace_fsmonitor,
+					 "ignoring '%s'", path_k);
+			break;
+		}
+	}
+
+	fsmonitor_publish(state, batch, &cookie_list);
+	string_list_clear(&cookie_list, 0);
+	strbuf_release(&tmp);
+	return;
+
+force_shutdown:
+	fsmonitor_batch__free_list(batch);
+	string_list_clear(&cookie_list, 0);
+
+	data->shutdown_style = FORCE_SHUTDOWN;
+	CFRunLoopStop(data->rl);
+	strbuf_release(&tmp);
+	return;
+}
+
+/*
+ * In the call to `FSEventStreamCreate()` to setup our watch, the
+ * `latency` argument determines the frequency of calls to our callback
+ * with new FS events.  Too slow and events get dropped; too fast and
+ * we burn CPU unnecessarily.  Since it is rather obscure, I don't
+ * think this needs to be a config setting.  I've done extensive
+ * testing on my systems and chosen the value below.  It gives good
+ * results and I've not seen any dropped events.
+ *
+ * With a latency of 0.1, I was seeing lots of dropped events during
+ * the "touch 100000" files test within t/perf/p7519, but with a
+ * latency of 0.001 I did not see any dropped events.  So I'm going
+ * to assume that this is the "correct" value.
+ *
+ * https://developer.apple.com/documentation/coreservices/1443980-fseventstreamcreate
+ */
+
+int fsm_listen__ctor(struct fsmonitor_daemon_state *state)
+{
+	FSEventStreamCreateFlags flags = kFSEventStreamCreateFlagNoDefer |
+		kFSEventStreamCreateFlagWatchRoot |
+		kFSEventStreamCreateFlagFileEvents;
+	FSEventStreamContext ctx = {
+		0,
+		state,
+		NULL,
+		NULL,
+		NULL
+	};
+	struct fsmonitor_daemon_backend_data *data;
+	const void *dir_array[2];
+
+	CALLOC_ARRAY(data, 1);
+	state->backend_data = data;
+
+	data->cfsr_worktree_path = CFStringCreateWithCString(
+		NULL, state->path_worktree_watch.buf, kCFStringEncodingUTF8);
+	dir_array[data->nr_paths_watching++] = data->cfsr_worktree_path;
+
+	if (state->nr_paths_watching > 1) {
+		data->cfsr_gitdir_path = CFStringCreateWithCString(
+			NULL, state->path_gitdir_watch.buf,
+			kCFStringEncodingUTF8);
+		dir_array[data->nr_paths_watching++] = data->cfsr_gitdir_path;
+	}
+
+	data->cfar_paths_to_watch = CFArrayCreate(NULL, dir_array,
+						  data->nr_paths_watching,
+						  NULL);
+	data->stream = FSEventStreamCreate(NULL, fsevent_callback, &ctx,
+					   data->cfar_paths_to_watch,
+					   kFSEventStreamEventIdSinceNow,
+					   0.001, flags);
+	if (data->stream == NULL)
+		goto failed;
+
+	/*
+	 * `data->rl` needs to be set inside the listener thread.
+	 */
+
+	return 0;
+
+failed:
+	error(_("Unable to create FSEventStream."));
+
+	FREE_AND_NULL(state->backend_data);
+	return -1;
+}
+
+void fsm_listen__dtor(struct fsmonitor_daemon_state *state)
+{
+	struct fsmonitor_daemon_backend_data *data;
+
+	if (!state || !state->backend_data)
+		return;
+
+	data = state->backend_data;
+
+	if (data->stream) {
+		if (data->stream_started)
+			FSEventStreamStop(data->stream);
+		if (data->stream_scheduled)
+			FSEventStreamInvalidate(data->stream);
+		FSEventStreamRelease(data->stream);
+	}
+
+	FREE_AND_NULL(state->backend_data);
+}
+
+void fsm_listen__stop_async(struct fsmonitor_daemon_state *state)
+{
+	struct fsmonitor_daemon_backend_data *data;
+
+	data = state->backend_data;
+	data->shutdown_style = SHUTDOWN_EVENT;
+
+	CFRunLoopStop(data->rl);
+}
+
+void fsm_listen__loop(struct fsmonitor_daemon_state *state)
+{
+	struct fsmonitor_daemon_backend_data *data;
+
+	data = state->backend_data;
+
+	data->rl = CFRunLoopGetCurrent();
+
+	FSEventStreamScheduleWithRunLoop(data->stream, data->rl, kCFRunLoopDefaultMode);
+	data->stream_scheduled = 1;
+
+	if (!FSEventStreamStart(data->stream)) {
+		error(_("Failed to start the FSEventStream"));
+		goto force_error_stop_without_loop;
+	}
+	data->stream_started = 1;
+
+	CFRunLoopRun();
+
+	switch (data->shutdown_style) {
+	case FORCE_ERROR_STOP:
+		state->error_code = -1;
+		/* fall thru */
+	case FORCE_SHUTDOWN:
+		ipc_server_stop_async(state->ipc_server_data);
+		/* fall thru */
+	case SHUTDOWN_EVENT:
+	default:
+		break;
+	}
+	return;
+
+force_error_stop_without_loop:
+	state->error_code = -1;
+	ipc_server_stop_async(state->ipc_server_data);
+	return;
+}

compat/fsmonitor/fsm-listen-win32.c

@@ -0,0 +1,586 @@
+#include "cache.h"
+#include "config.h"
+#include "fsmonitor.h"
+#include "fsm-listen.h"
+#include "fsmonitor--daemon.h"
+
+/*
+ * The documentation of ReadDirectoryChangesW() states that the maximum
+ * buffer size is 64K when the monitored directory is remote.
+ *
+ * Larger buffers may be used when the monitored directory is local and
+ * will help us receive events faster from the kernel and avoid dropped
+ * events.
+ *
+ * So we try to use a very large buffer and silently fallback to 64K if
+ * we get an error.
+ */
+#define MAX_RDCW_BUF_FALLBACK (65536)
+#define MAX_RDCW_BUF          (65536 * 8)
+
+struct one_watch
+{
+	char buffer[MAX_RDCW_BUF];
+	DWORD buf_len;
+	DWORD count;
+
+	struct strbuf path;
+	HANDLE hDir;
+	HANDLE hEvent;
+	OVERLAPPED overlapped;
+
+	/*
+	 * Is there an active ReadDirectoryChangesW() call pending.  If so, we
+	 * need to later call GetOverlappedResult() and possibly CancelIoEx().
+	 */
+	BOOL is_active;
+};
+
+struct fsmonitor_daemon_backend_data
+{
+	struct one_watch *watch_worktree;
+	struct one_watch *watch_gitdir;
+
+	HANDLE hEventShutdown;
+
+	HANDLE hListener[3]; /* we don't own these handles */
+#define LISTENER_SHUTDOWN 0
+#define LISTENER_HAVE_DATA_WORKTREE 1
+#define LISTENER_HAVE_DATA_GITDIR 2
+	int nr_listener_handles;
+};
+
+/*
+ * Convert the WCHAR path from the notification into UTF8 and
+ * then normalize it.
+ */
+static int normalize_path_in_utf8(FILE_NOTIFY_INFORMATION *info,
+				  struct strbuf *normalized_path)
+{
+	int reserve;
+	int len = 0;
+
+	strbuf_reset(normalized_path);
+	if (!info->FileNameLength)
+		goto normalize;
+
+	/*
+	 * Pre-reserve enough space in the UTF8 buffer for
+	 * each Unicode WCHAR character to be mapped into a
+	 * sequence of 2 UTF8 characters.  That should let us
+	 * avoid ERROR_INSUFFICIENT_BUFFER 99.9+% of the time.
+	 */
+	reserve = info->FileNameLength + 1;
+	strbuf_grow(normalized_path, reserve);
+
+	for (;;) {
+		len = WideCharToMultiByte(CP_UTF8, 0, info->FileName,
+					  info->FileNameLength / sizeof(WCHAR),
+					  normalized_path->buf,
+					  strbuf_avail(normalized_path) - 1,
+					  NULL, NULL);
+		if (len > 0)
+			goto normalize;
+		if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
+			error(_("[GLE %ld] could not convert path to UTF-8: '%.*ls'"),
+			      GetLastError(),
+			      (int)(info->FileNameLength / sizeof(WCHAR)),
+			      info->FileName);
+			return -1;
+		}
+
+		strbuf_grow(normalized_path,
+			    strbuf_avail(normalized_path) + reserve);
+	}
+
+normalize:
+	strbuf_setlen(normalized_path, len);
+	return strbuf_normalize_path(normalized_path);
+}
+
+void fsm_listen__stop_async(struct fsmonitor_daemon_state *state)
+{
+	SetEvent(state->backend_data->hListener[LISTENER_SHUTDOWN]);
+}
+
+static struct one_watch *create_watch(struct fsmonitor_daemon_state *state,
+				      const char *path)
+{
+	struct one_watch *watch = NULL;
+	DWORD desired_access = FILE_LIST_DIRECTORY;
+	DWORD share_mode =
+		FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE;
+	HANDLE hDir;
+	wchar_t wpath[MAX_PATH];
+
+	if (xutftowcs_path(wpath, path) < 0) {
+		error(_("could not convert to wide characters: '%s'"), path);
+		return NULL;
+	}
+
+	hDir = CreateFileW(wpath,
+			   desired_access, share_mode, NULL, OPEN_EXISTING,
+			   FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
+			   NULL);
+	if (hDir == INVALID_HANDLE_VALUE) {
+		error(_("[GLE %ld] could not watch '%s'"),
+		      GetLastError(), path);
+		return NULL;
+	}
+
+	CALLOC_ARRAY(watch, 1);
+
+	watch->buf_len = sizeof(watch->buffer); /* assume full MAX_RDCW_BUF */
+
+	strbuf_init(&watch->path, 0);
+	strbuf_addstr(&watch->path, path);
+
+	watch->hDir = hDir;
+	watch->hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
+
+	return watch;
+}
+
+static void destroy_watch(struct one_watch *watch)
+{
+	if (!watch)
+		return;
+
+	strbuf_release(&watch->path);
+	if (watch->hDir != INVALID_HANDLE_VALUE)
+		CloseHandle(watch->hDir);
+	if (watch->hEvent != INVALID_HANDLE_VALUE)
+		CloseHandle(watch->hEvent);
+
+	free(watch);
+}
+
+static int start_rdcw_watch(struct fsmonitor_daemon_backend_data *data,
+			    struct one_watch *watch)
+{
+	DWORD dwNotifyFilter =
+		FILE_NOTIFY_CHANGE_FILE_NAME |
+		FILE_NOTIFY_CHANGE_DIR_NAME |
+		FILE_NOTIFY_CHANGE_ATTRIBUTES |
+		FILE_NOTIFY_CHANGE_SIZE |
+		FILE_NOTIFY_CHANGE_LAST_WRITE |
+		FILE_NOTIFY_CHANGE_CREATION;
+
+	ResetEvent(watch->hEvent);
+
+	memset(&watch->overlapped, 0, sizeof(watch->overlapped));
+	watch->overlapped.hEvent = watch->hEvent;
+
+	/*
+	 * Queue an async call using Overlapped IO.  This returns immediately.
+	 * Our event handle will be signalled when the real result is available.
+	 *
+	 * The return value here just means that we successfully queued it.
+	 * We won't know if the Read...() actually produces data until later.
+	 */
+	watch->is_active = ReadDirectoryChangesW(
+		watch->hDir, watch->buffer, watch->buf_len, TRUE,
+		dwNotifyFilter, &watch->count, &watch->overlapped, NULL);
+
+	if (watch->is_active)
+		return 0;
+
+	error(_("ReadDirectoryChangedW failed on '%s' [GLE %ld]"),
+	      watch->path.buf, GetLastError());
+	return -1;
+}
+
+static int recv_rdcw_watch(struct one_watch *watch)
+{
+	DWORD gle;
+
+	watch->is_active = FALSE;
+
+	/*
+	 * The overlapped result is ready.  If the Read...() was successful
+	 * we finally receive the actual result into our buffer.
+	 */
+	if (GetOverlappedResult(watch->hDir, &watch->overlapped, &watch->count,
+				TRUE))
+		return 0;
+
+	gle = GetLastError();
+	if (gle == ERROR_INVALID_PARAMETER &&
+	    /*
+	     * The kernel throws an invalid parameter error when our
+	     * buffer is too big and we are pointed at a remote
+	     * directory (and possibly for other reasons).  Quietly
+	     * set it down and try again.
+	     *
+	     * See note about MAX_RDCW_BUF at the top.
+	     */
+	    watch->buf_len > MAX_RDCW_BUF_FALLBACK) {
+		watch->buf_len = MAX_RDCW_BUF_FALLBACK;
+		return -2;
+	}
+
+	/*
+	 * NEEDSWORK: If an external <gitdir> is deleted, the above
+	 * returns an error.  I'm not sure that there's anything that
+	 * we can do here other than failing -- the <worktree>/.git
+	 * link file would be broken anyway.  We might try to check
+	 * for that and return a better error message, but I'm not
+	 * sure it is worth it.
+	 */
+
+	error(_("GetOverlappedResult failed on '%s' [GLE %ld]"),
+	      watch->path.buf, gle);
+	return -1;
+}
+
+static void cancel_rdcw_watch(struct one_watch *watch)
+{
+	DWORD count;
+
+	if (!watch || !watch->is_active)
+		return;
+
+	/*
+	 * The calls to ReadDirectoryChangesW() and GetOverlappedResult()
+	 * form a "pair" (my term) where we queue an IO and promise to
+	 * hang around and wait for the kernel to give us the result.
+	 *
+	 * If for some reason after we queue the IO, we have to quit
+	 * or otherwise not stick around for the second half, we must
+	 * tell the kernel to abort the IO.  This prevents the kernel
+	 * from writing to our buffer and/or signalling our event
+	 * after we free them.
+	 *
+	 * (Ask me how much fun it was to track that one down).
+	 */
+	CancelIoEx(watch->hDir, &watch->overlapped);
+	GetOverlappedResult(watch->hDir, &watch->overlapped, &count, TRUE);
+	watch->is_active = FALSE;
+}
+
+/*
+ * Process filesystem events that happen anywhere (recursively) under the
+ * <worktree> root directory.  For a normal working directory, this includes
+ * both version controlled files and the contents of the .git/ directory.
+ *
+ * If <worktree>/.git is a file, then we only see events for the file
+ * itself.
+ */
+static int process_worktree_events(struct fsmonitor_daemon_state *state)
+{
+	struct fsmonitor_daemon_backend_data *data = state->backend_data;
+	struct one_watch *watch = data->watch_worktree;
+	struct strbuf path = STRBUF_INIT;
+	struct string_list cookie_list = STRING_LIST_INIT_DUP;
+	struct fsmonitor_batch *batch = NULL;
+	const char *p = watch->buffer;
+
+	/*
+	 * If the kernel gets more events than will fit in the kernel
+	 * buffer associated with our RDCW handle, it drops them and
+	 * returns a count of zero.
+	 *
+	 * Yes, the call returns WITHOUT error and with length zero.
+	 * This is the documented behavior.  (My testing has confirmed
+	 * that it also sets the last error to ERROR_NOTIFY_ENUM_DIR,
+	 * but we do not rely on that since the function did not
+	 * return an error and it is not documented.)
+	 *
+	 * (The "overflow" case is not ambiguous with the "no data" case
+	 * because we did an INFINITE wait.)
+	 *
+	 * This means we have a gap in coverage.  Tell the daemon layer
+	 * to resync.
+	 */
+	if (!watch->count) {
+		trace2_data_string("fsmonitor", NULL, "fsm-listen/kernel",
+				   "overflow");
+		fsmonitor_force_resync(state);
+		return LISTENER_HAVE_DATA_WORKTREE;
+	}
+
+	/*
+	 * On Windows, `info` contains an "array" of paths that are
+	 * relative to the root of whichever directory handle received
+	 * the event.
+	 */
+	for (;;) {
+		FILE_NOTIFY_INFORMATION *info = (void *)p;
+		const char *slash;
+		enum fsmonitor_path_type t;
+
+		strbuf_reset(&path);
+		if (normalize_path_in_utf8(info, &path) == -1)
+			goto skip_this_path;
+
+		t = fsmonitor_classify_path_workdir_relative(path.buf);
+
+		switch (t) {
+		case IS_INSIDE_DOT_GIT_WITH_COOKIE_PREFIX:
+			/* special case cookie files within .git */
+
+			/* Use just the filename of the cookie file. */
+			slash = find_last_dir_sep(path.buf);
+			string_list_append(&cookie_list,
+					   slash ? slash + 1 : path.buf);
+			break;
+
+		case IS_INSIDE_DOT_GIT:
+			/* ignore everything inside of "<worktree>/.git/" */
+			break;
+
+		case IS_DOT_GIT:
+			/* "<worktree>/.git" was deleted (or renamed away) */
+			if ((info->Action == FILE_ACTION_REMOVED) ||
+			    (info->Action == FILE_ACTION_RENAMED_OLD_NAME)) {
+				trace2_data_string("fsmonitor", NULL,
+						   "fsm-listen/dotgit",
+						   "removed");
+				goto force_shutdown;
+			}
+			break;
+
+		case IS_WORKDIR_PATH:
+			/* queue normal pathname */
+			if (!batch)
+				batch = fsmonitor_batch__new();
+			fsmonitor_batch__add_path(batch, path.buf);
+			break;
+
+		case IS_GITDIR:
+		case IS_INSIDE_GITDIR:
+		case IS_INSIDE_GITDIR_WITH_COOKIE_PREFIX:
+		default:
+			BUG("unexpected path classification '%d' for '%s'",
+			    t, path.buf);
+		}
+
+skip_this_path:
+		if (!info->NextEntryOffset)
+			break;
+		p += info->NextEntryOffset;
+	}
+
+	fsmonitor_publish(state, batch, &cookie_list);
+	batch = NULL;
+	string_list_clear(&cookie_list, 0);
+	strbuf_release(&path);
+	return LISTENER_HAVE_DATA_WORKTREE;
+
+force_shutdown:
+	fsmonitor_batch__free_list(batch);
+	string_list_clear(&cookie_list, 0);
+	strbuf_release(&path);
+	return LISTENER_SHUTDOWN;
+}
+
+/*
+ * Process filesystem events that happened anywhere (recursively) under the
+ * external <gitdir> (such as non-primary worktrees or submodules).
+ * We only care about cookie files that our client threads created here.
+ *
+ * Note that we DO NOT get filesystem events on the external <gitdir>
+ * itself (it is not inside something that we are watching).  In particular,
+ * we do not get an event if the external <gitdir> is deleted.
+ */
+static int process_gitdir_events(struct fsmonitor_daemon_state *state)
+{
+	struct fsmonitor_daemon_backend_data *data = state->backend_data;
+	struct one_watch *watch = data->watch_gitdir;
+	struct strbuf path = STRBUF_INIT;
+	struct string_list cookie_list = STRING_LIST_INIT_DUP;
+	const char *p = watch->buffer;
+
+	if (!watch->count) {
+		trace2_data_string("fsmonitor", NULL, "fsm-listen/kernel",
+				   "overflow");
+		fsmonitor_force_resync(state);
+		return LISTENER_HAVE_DATA_GITDIR;
+	}
+
+	for (;;) {
+		FILE_NOTIFY_INFORMATION *info = (void *)p;
+		const char *slash;
+		enum fsmonitor_path_type t;
+
+		strbuf_reset(&path);
+		if (normalize_path_in_utf8(info, &path) == -1)
+			goto skip_this_path;
+
+		t = fsmonitor_classify_path_gitdir_relative(path.buf);
+
+		switch (t) {
+		case IS_INSIDE_GITDIR_WITH_COOKIE_PREFIX:
+			/* special case cookie files within gitdir */
+
+			/* Use just the filename of the cookie file. */
+			slash = find_last_dir_sep(path.buf);
+			string_list_append(&cookie_list,
+					   slash ? slash + 1 : path.buf);
+			break;
+
+		case IS_INSIDE_GITDIR:
+			goto skip_this_path;
+
+		default:
+			BUG("unexpected path classification '%d' for '%s'",
+			    t, path.buf);
+		}
+
+skip_this_path:
+		if (!info->NextEntryOffset)
+			break;
+		p += info->NextEntryOffset;
+	}
+
+	fsmonitor_publish(state, NULL, &cookie_list);
+	string_list_clear(&cookie_list, 0);
+	strbuf_release(&path);
+	return LISTENER_HAVE_DATA_GITDIR;
+}
+
+void fsm_listen__loop(struct fsmonitor_daemon_state *state)
+{
+	struct fsmonitor_daemon_backend_data *data = state->backend_data;
+	DWORD dwWait;
+	int result;
+
+	state->error_code = 0;
+
+	if (start_rdcw_watch(data, data->watch_worktree) == -1)
+		goto force_error_stop;
+
+	if (data->watch_gitdir &&
+	    start_rdcw_watch(data, data->watch_gitdir) == -1)
+		goto force_error_stop;
+
+	for (;;) {
+		dwWait = WaitForMultipleObjects(data->nr_listener_handles,
+						data->hListener,
+						FALSE, INFINITE);
+
+		if (dwWait == WAIT_OBJECT_0 + LISTENER_HAVE_DATA_WORKTREE) {
+			result = recv_rdcw_watch(data->watch_worktree);
+			if (result == -1) {
+				/* hard error */
+				goto force_error_stop;
+			}
+			if (result == -2) {
+				/* retryable error */
+				if (start_rdcw_watch(data, data->watch_worktree) == -1)
+					goto force_error_stop;
+				continue;
+			}
+
+			/* have data */
+			if (process_worktree_events(state) == LISTENER_SHUTDOWN)
+				goto force_shutdown;
+			if (start_rdcw_watch(data, data->watch_worktree) == -1)
+				goto force_error_stop;
+			continue;
+		}
+
+		if (dwWait == WAIT_OBJECT_0 + LISTENER_HAVE_DATA_GITDIR) {
+			result = recv_rdcw_watch(data->watch_gitdir);
+			if (result == -1) {
+				/* hard error */
+				goto force_error_stop;
+			}
+			if (result == -2) {
+				/* retryable error */
+				if (start_rdcw_watch(data, data->watch_gitdir) == -1)
+					goto force_error_stop;
+				continue;
+			}
+
+			/* have data */
+			if (process_gitdir_events(state) == LISTENER_SHUTDOWN)
+				goto force_shutdown;
+			if (start_rdcw_watch(data, data->watch_gitdir) == -1)
+				goto force_error_stop;
+			continue;
+		}
+
+		if (dwWait == WAIT_OBJECT_0 + LISTENER_SHUTDOWN)
+			goto clean_shutdown;
+
+		error(_("could not read directory changes [GLE %ld]"),
+		      GetLastError());
+		goto force_error_stop;
+	}
+
+force_error_stop:
+	state->error_code = -1;
+
+force_shutdown:
+	/*
+	 * Tell the IPC thead pool to stop (which completes the await
+	 * in the main thread (which will also signal this thread (if
+	 * we are still alive))).
+	 */
+	ipc_server_stop_async(state->ipc_server_data);
+
+clean_shutdown:
+	cancel_rdcw_watch(data->watch_worktree);
+	cancel_rdcw_watch(data->watch_gitdir);
+}
+
+int fsm_listen__ctor(struct fsmonitor_daemon_state *state)
+{
+	struct fsmonitor_daemon_backend_data *data;
+
+	CALLOC_ARRAY(data, 1);
+
+	data->hEventShutdown = CreateEvent(NULL, TRUE, FALSE, NULL);
+
+	data->watch_worktree = create_watch(state,
+					    state->path_worktree_watch.buf);
+	if (!data->watch_worktree)
+		goto failed;
+
+	if (state->nr_paths_watching > 1) {
+		data->watch_gitdir = create_watch(state,
+						  state->path_gitdir_watch.buf);
+		if (!data->watch_gitdir)
+			goto failed;
+	}
+
+	data->hListener[LISTENER_SHUTDOWN] = data->hEventShutdown;
+	data->nr_listener_handles++;
+
+	data->hListener[LISTENER_HAVE_DATA_WORKTREE] =
+		data->watch_worktree->hEvent;
+	data->nr_listener_handles++;
+
+	if (data->watch_gitdir) {
+		data->hListener[LISTENER_HAVE_DATA_GITDIR] =
+			data->watch_gitdir->hEvent;
+		data->nr_listener_handles++;
+	}
+
+	state->backend_data = data;
+	return 0;
+
+failed:
+	CloseHandle(data->hEventShutdown);
+	destroy_watch(data->watch_worktree);
+	destroy_watch(data->watch_gitdir);
+
+	return -1;
+}
+
+void fsm_listen__dtor(struct fsmonitor_daemon_state *state)
+{
+	struct fsmonitor_daemon_backend_data *data;
+
+	if (!state || !state->backend_data)
+		return;
+
+	data = state->backend_data;
+
+	CloseHandle(data->hEventShutdown);
+	destroy_watch(data->watch_worktree);
+	destroy_watch(data->watch_gitdir);
+
+	FREE_AND_NULL(state->backend_data);
+}

compat/fsmonitor/fsm-listen.h

@@ -0,0 +1,49 @@
+#ifndef FSM_LISTEN_H
+#define FSM_LISTEN_H
+
+/* This needs to be implemented by each backend */
+
+#ifdef HAVE_FSMONITOR_DAEMON_BACKEND
+
+struct fsmonitor_daemon_state;
+
+/*
+ * Initialize platform-specific data for the fsmonitor listener thread.
+ * This will be called from the main thread PRIOR to staring the
+ * fsmonitor_fs_listener thread.
+ *
+ * Returns 0 if successful.
+ * Returns -1 otherwise.
+ */
+int fsm_listen__ctor(struct fsmonitor_daemon_state *state);
+
+/*
+ * Cleanup platform-specific data for the fsmonitor listener thread.
+ * This will be called from the main thread AFTER joining the listener.
+ */
+void fsm_listen__dtor(struct fsmonitor_daemon_state *state);
+
+/*
+ * The main body of the platform-specific event loop to watch for
+ * filesystem events.  This will run in the fsmonitor_fs_listen thread.
+ *
+ * It should call `ipc_server_stop_async()` if the listener thread
+ * prematurely terminates (because of a filesystem error or if it
+ * detects that the .git directory has been deleted).  (It should NOT
+ * do so if the listener thread receives a normal shutdown signal from
+ * the IPC layer.)
+ *
+ * It should set `state->error_code` to -1 if the daemon should exit
+ * with an error.
+ */
+void fsm_listen__loop(struct fsmonitor_daemon_state *state);
+
+/*
+ * Gently request that the fsmonitor listener thread shutdown.
+ * It does not wait for it to stop.  The caller should do a JOIN
+ * to wait for it.
+ */
+void fsm_listen__stop_async(struct fsmonitor_daemon_state *state);
+
+#endif /* HAVE_FSMONITOR_DAEMON_BACKEND */
+#endif /* FSM_LISTEN_H */

config.c

@@ -6,6 +6,7 @@
  *
  */
 #include "cache.h"
+#include "date.h"
 #include "branch.h"
 #include "config.h"
 #include "environment.h"
@@ -21,6 +22,7 @@
 #include "dir.h"
 #include "color.h"
 #include "refs.h"
+#include "worktree.h"
 
 struct config_source {
 	struct config_source *prev;
@@ -2294,8 +2296,8 @@ int git_configset_get_string(struct config_set *cs, const char *key, char **dest
 		return 1;
 }
 
-int git_configset_get_string_tmp(struct config_set *cs, const char *key,
-				 const char **dest)
+static int git_configset_get_string_tmp(struct config_set *cs, const char *key,
+					const char **dest)
 {
 	const char *value;
 	if (!git_configset_get_value(cs, key, &value)) {
@@ -2624,20 +2626,6 @@ int git_config_get_max_percent_split_change(void)
 	return -1; /* default value */
 }
 
-int git_config_get_fsmonitor(void)
-{
-	if (git_config_get_pathname("core.fsmonitor", &core_fsmonitor))
-		core_fsmonitor = getenv("GIT_TEST_FSMONITOR");
-
-	if (core_fsmonitor && !*core_fsmonitor)
-		core_fsmonitor = NULL;
-
-	if (core_fsmonitor)
-		return 1;
-
-	return 0;
-}
-
 int git_config_get_index_threads(int *dest)
 {
 	int is_bool, val;
@@ -3000,6 +2988,20 @@ int git_config_set_gently(const char *key, const char *value)
 	return git_config_set_multivar_gently(key, value, NULL, 0);
 }
 
+int repo_config_set_worktree_gently(struct repository *r,
+				    const char *key, const char *value)
+{
+	/* Only use worktree-specific config if it is is already enabled. */
+	if (repository_format_worktree_config) {
+		char *file = repo_git_path(r, "config.worktree");
+		int ret = git_config_set_multivar_in_file_gently(
+					file, key, value, NULL, 0);
+		free(file);
+		return ret;
+	}
+	return repo_config_set_multivar_gently(r, key, value, NULL, 0);
+}
+
 void git_config_set(const char *key, const char *value)
 {
 	git_config_set_multivar(key, value, NULL, 0);
@@ -3297,14 +3299,28 @@ void git_config_set_multivar_in_file(const char *config_filename,
 int git_config_set_multivar_gently(const char *key, const char *value,
 				   const char *value_pattern, unsigned flags)
 {
-	return git_config_set_multivar_in_file_gently(NULL, key, value, value_pattern,
-						      flags);
+	return repo_config_set_multivar_gently(the_repository, key, value,
+					       value_pattern, flags);
+}
+
+int repo_config_set_multivar_gently(struct repository *r, const char *key,
+				    const char *value,
+				    const char *value_pattern, unsigned flags)
+{
+	char *file = repo_git_path(r, "config");
+	int res = git_config_set_multivar_in_file_gently(file,
+							 key, value,
+							 value_pattern,
+							 flags);
+	free(file);
+	return res;
 }
 
 void git_config_set_multivar(const char *key, const char *value,
 			     const char *value_pattern, unsigned flags)
 {
-	git_config_set_multivar_in_file(NULL, key, value, value_pattern,
+	git_config_set_multivar_in_file(git_path("config"),
+					key, value, value_pattern,
 					flags);
 }
 

config.h

@@ -266,6 +266,13 @@ void git_config_set_in_file(const char *, const char *, const char *);
 
 int git_config_set_gently(const char *, const char *);
 
+/**
+ * Write a config value that should apply to the current worktree. If
+ * extensions.worktreeConfig is enabled, then the write will happen in the
+ * current worktree's config. Otherwise, write to the common config file.
+ */
+int repo_config_set_worktree_gently(struct repository *, const char *, const char *);
+
 /**
  * write config values to `.git/config`, takes a key/value pair as parameter.
  */
@@ -294,6 +301,7 @@ int git_config_parse_key(const char *, char **, size_t *);
 
 int git_config_set_multivar_gently(const char *, const char *, const char *, unsigned);
 void git_config_set_multivar(const char *, const char *, const char *, unsigned);
+int repo_config_set_multivar_gently(struct repository *, const char *, const char *, const char *, unsigned);
 int git_config_set_multivar_in_file_gently(const char *, const char *, const char *, const char *, unsigned);
 
 /**
@@ -466,7 +474,6 @@ void git_configset_clear(struct config_set *cs);
 int git_configset_get_value(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);
@@ -590,7 +597,6 @@ int git_config_get_pathname(const char *key, const char **dest);
 int git_config_get_index_threads(int *dest);
 int git_config_get_split_index(void);
 int git_config_get_max_percent_split_change(void);
-int git_config_get_fsmonitor(void);
 
 /* This dies if the configured or default date is in the future */
 int git_config_get_expiry(const char *key, const char **output);

config.mak.uname

@@ -157,6 +157,16 @@ ifeq ($(uname_S),Darwin)
 			MSGFMT = /usr/local/opt/gettext/bin/msgfmt
 		endif
 	endif
+
+	# The builtin FSMonitor on MacOS builds upon Simple-IPC.  Both require
+	# Unix domain sockets and PThreads.
+	ifndef NO_PTHREADS
+	ifndef NO_UNIX_SOCKETS
+	FSMONITOR_DAEMON_BACKEND = darwin
+	endif
+	endif
+
+	BASIC_LDFLAGS += -framework CoreServices
 endif
 ifeq ($(uname_S),SunOS)
 	NEEDS_SOCKET = YesPlease
@@ -435,6 +445,11 @@ ifeq ($(uname_S),Windows)
 	# so we don't need this:
 	#
 	#   SNPRINTF_RETURNS_BOGUS = YesPlease
+
+	# The builtin FSMonitor requires Named Pipes and Threads on Windows.
+	# These are always available, so we do not have to conditionally
+	# support it.
+	FSMONITOR_DAEMON_BACKEND = win32
 	NO_SVN_TESTS = YesPlease
 	RUNTIME_PREFIX = YesPlease
 	HAVE_WPGMPTR = YesWeDo
@@ -619,6 +634,11 @@ ifeq ($(uname_S),MINGW)
 	NO_STRTOUMAX = YesPlease
 	NO_MKDTEMP = YesPlease
 	NO_SVN_TESTS = YesPlease
+
+	# The builtin FSMonitor requires Named Pipes and Threads on Windows.
+	# These are always available, so we do not have to conditionally
+	# support it.
+	FSMONITOR_DAEMON_BACKEND = win32
 	RUNTIME_PREFIX = YesPlease
 	HAVE_WPGMPTR = YesWeDo
 	NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease

connect.c

@@ -379,7 +379,7 @@ struct ref **get_remote_heads(struct packet_reader *reader,
 
 /* Returns 1 when a valid ref has been added to `list`, 0 otherwise */
 static int process_ref_v2(struct packet_reader *reader, struct ref ***list,
-			  char **unborn_head_target)
+			  const char **unborn_head_target)
 {
 	int ret = 1;
 	int i = 0;
@@ -483,7 +483,7 @@ struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
 	const char *hash_name;
 	struct strvec *ref_prefixes = transport_options ?
 		&transport_options->ref_prefixes : NULL;
-	char **unborn_head_target = transport_options ?
+	const char **unborn_head_target = transport_options ?
 		&transport_options->unborn_head_target : NULL;
 	*list = NULL;
 

contrib/buildsystems/CMakeLists.txt

@@ -285,6 +285,16 @@ else()
 	endif()
 endif()
 
+if(SUPPORTS_SIMPLE_IPC)
+	if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
+		add_compile_definitions(HAVE_FSMONITOR_DAEMON_BACKEND)
+		list(APPEND compat_SOURCES compat/fsmonitor/fsm-listen-win32.c)
+	elseif(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
+		add_compile_definitions(HAVE_FSMONITOR_DAEMON_BACKEND)
+		list(APPEND compat_SOURCES compat/fsmonitor/fsm-listen-darwin.c)
+	endif()
+endif()
+
 set(EXE_EXTENSION ${CMAKE_EXECUTABLE_SUFFIX})
 
 #header checks

contrib/completion/git-completion.bash

@@ -49,6 +49,11 @@
 #     and git-switch completion (e.g., completing "foo" when "origin/foo"
 #     exists).
 #
+#   GIT_COMPLETION_SHOW_ALL_COMMANDS
+#
+#     When set to "1" suggest all commands, including plumbing commands
+#     which are hidden by default (e.g. "cat-file" on "git ca<TAB>").
+#
 #   GIT_COMPLETION_SHOW_ALL
 #
 #     When set to "1" suggest all options, including options which are
@@ -3483,7 +3488,13 @@ __git_main ()
 			then
 				__gitcomp "$GIT_TESTING_PORCELAIN_COMMAND_LIST"
 			else
-				__gitcomp "$(__git --list-cmds=list-mainporcelain,others,nohelpers,alias,list-complete,config)"
+				local list_cmds=list-mainporcelain,others,nohelpers,alias,list-complete,config
+
+				if test "${GIT_COMPLETION_SHOW_ALL_COMMANDS-}" = "1"
+				then
+					list_cmds=builtins,$list_cmds
+				fi
+				__gitcomp "$(__git --list-cmds=$list_cmds)"
 			fi
 			;;
 		esac

contrib/scalar/scalar.c

@@ -808,6 +808,25 @@ int cmd_main(int argc, const char **argv)
 	struct strbuf scalar_usage = STRBUF_INIT;
 	int i;
 
+	while (argc > 1 && *argv[1] == '-') {
+		if (!strcmp(argv[1], "-C")) {
+			if (argc < 3)
+				die(_("-C requires a <directory>"));
+			if (chdir(argv[2]) < 0)
+				die_errno(_("could not change to '%s'"),
+					  argv[2]);
+			argc -= 2;
+			argv += 2;
+		} else if (!strcmp(argv[1], "-c")) {
+			if (argc < 3)
+				die(_("-c requires a <key>=<value> argument"));
+			git_config_push_parameter(argv[2]);
+			argc -= 2;
+			argv += 2;
+		} else
+			break;
+	}
+
 	if (argc > 1) {
 		argv++;
 		argc--;
@@ -818,7 +837,8 @@ int cmd_main(int argc, const char **argv)
 	}
 
 	strbuf_addstr(&scalar_usage,
-		      N_("scalar <command> [<options>]\n\nCommands:\n"));
+		      N_("scalar [-C <directory>] [-c <key>=<value>] "
+			 "<command> [<options>]\n\nCommands:\n"));
 	for (i = 0; builtins[i].name; i++)
 		strbuf_addf(&scalar_usage, "\t%s\n", builtins[i].name);
 

contrib/scalar/scalar.txt

@@ -36,6 +36,16 @@ The `scalar` command implements various subcommands, and different options
 depending on the subcommand. With the exception of `clone`, `list` and
 `reconfigure --all`, all subcommands expect to be run in an enlistment.
 
+The following options can be specified _before_ the subcommand:
+
+-C <directory>::
+	Before running the subcommand, change the working directory. This
+	option imitates the same option of linkgit:git[1].
+
+-c <key>=<value>::
+	For the duration of running the specified subcommand, configure this
+	setting. This option imitates the same option of linkgit:git[1].
+
 COMMANDS
 --------
 

contrib/scalar/t/t9099-scalar.sh

@@ -85,4 +85,12 @@ test_expect_success 'scalar delete with enlistment' '
 	test_path_is_missing cloned
 '
 
+test_expect_success 'scalar supports -c/-C' '
+	test_when_finished "scalar delete sub" &&
+	git init sub &&
+	scalar -C sub -c status.aheadBehind=bogus register &&
+	test -z "$(git -C sub config --local status.aheadBehind)" &&
+	test true = "$(git -C sub config core.preloadIndex)"
+'
+
 test_done

contrib/subtree/git-subtree.sh

@@ -975,10 +975,10 @@ cmd_merge () {
 
 	if test -n "$arg_addmerge_message"
 	then
-		git merge -Xsubtree="$arg_prefix" \
+		git merge --no-ff -Xsubtree="$arg_prefix" \
 			--message="$arg_addmerge_message" "$rev"
 	else
-		git merge -Xsubtree="$arg_prefix" $rev
+		git merge --no-ff -Xsubtree="$arg_prefix" $rev
 	fi
 }
 

date.c

@@ -5,6 +5,7 @@
  */
 
 #include "cache.h"
+#include "date.h"
 
 /*
  * This is like mktime, but without normalization of tm_wday and tm_yday.
@@ -205,11 +206,10 @@ void show_date_relative(timestamp_t time, struct strbuf *timebuf)
 
 struct date_mode *date_mode_from_type(enum date_mode_type type)
 {
-	static struct date_mode mode;
+	static struct date_mode mode = DATE_MODE_INIT;
 	if (type == DATE_STRFTIME)
 		BUG("cannot create anonymous strftime date_mode struct");
 	mode.type = type;
-	mode.local = 0;
 	return &mode;
 }
 
@@ -993,6 +993,11 @@ void parse_date_format(const char *format, struct date_mode *mode)
 		die("unknown date format %s", format);
 }
 
+void date_mode_release(struct date_mode *mode)
+{
+	free((char *)mode->strftime_fmt);
+}
+
 void datestamp(struct strbuf *out)
 {
 	time_t now;

date.h

@@ -0,0 +1,74 @@
+#ifndef DATE_H
+#define DATE_H
+
+/**
+ * The date mode type. This has DATE_NORMAL at an explicit "= 0" to
+ * accommodate a memset([...], 0, [...]) initialization when "struct
+ * date_mode" is used as an embedded struct member, as in the case of
+ * e.g. "struct pretty_print_context" and "struct rev_info".
+ */
+enum date_mode_type {
+	DATE_NORMAL = 0,
+	DATE_HUMAN,
+	DATE_RELATIVE,
+	DATE_SHORT,
+	DATE_ISO8601,
+	DATE_ISO8601_STRICT,
+	DATE_RFC2822,
+	DATE_STRFTIME,
+	DATE_RAW,
+	DATE_UNIX
+};
+
+struct date_mode {
+	enum date_mode_type type;
+	const char *strftime_fmt;
+	int local;
+};
+
+#define DATE_MODE_INIT { \
+	.type = DATE_NORMAL, \
+}
+
+/**
+ * Convenience helper for passing a constant type, like:
+ *
+ *   show_date(t, tz, DATE_MODE(NORMAL));
+ */
+#define DATE_MODE(t) date_mode_from_type(DATE_##t)
+struct date_mode *date_mode_from_type(enum date_mode_type type);
+
+/**
+ * Format <'time', 'timezone'> into static memory according to 'mode'
+ * and return it. The mode is an initialized "struct date_mode"
+ * (usually from the DATE_MODE() macro).
+ */
+const char *show_date(timestamp_t time, int timezone, const struct date_mode *mode);
+
+/**
+ * Parse a date format for later use with show_date().
+ *
+ * When the "date_mode_type" is DATE_STRFTIME the "strftime_fmt"
+ * member of "struct date_mode" will be a malloc()'d format string to
+ * be used with strbuf_addftime(), in which case you'll need to call
+ * date_mode_release() later.
+ */
+void parse_date_format(const char *format, struct date_mode *mode);
+
+/**
+ * Release a "struct date_mode", currently only required if
+ * parse_date_format() has parsed a "DATE_STRFTIME" format.
+ */
+void date_mode_release(struct date_mode *mode);
+
+void show_date_relative(timestamp_t time, struct strbuf *timebuf);
+int parse_date(const char *date, struct strbuf *out);
+int parse_date_basic(const char *date, timestamp_t *timestamp, int *offset);
+int parse_expiry_date(const char *date, timestamp_t *timestamp);
+void datestamp(struct strbuf *out);
+#define approxidate(s) approxidate_careful((s), NULL)
+timestamp_t approxidate_careful(const char *, int *);
+timestamp_t approxidate_relative(const char *date);
+int date_overflows(timestamp_t date);
+time_t tm_to_time_t(const struct tm *tm);
+#endif

diff-merges.c

@@ -78,7 +78,7 @@ static void set_diff_merges(struct rev_info *revs, const char *optarg)
 	diff_merges_setup_func_t func = func_by_opt(optarg);
 
 	if (!func)
-		die(_("unknown value for --diff-merges: %s"), optarg);
+		die(_("invalid value for '%s': '%s'"), "--diff-merges", optarg);
 
 	func(revs);
 

diff.c

@@ -6452,6 +6452,8 @@ void diff_free(struct diff_options *options)
 
 	diff_free_file(options);
 	diff_free_ignore_regex(options);
+	clear_pathspec(&options->pathspec);
+	FREE_AND_NULL(options->parseopts);
 }
 
 void diff_flush(struct diff_options *options)