Log message:
git: updated to 2.20.1

Git v2.20.1:

This release is primarily to fix brown-paper-bag breakages in the
2.20.0 release.

Fixes since v2.20

 * A few newly added tests were not portable and caused minority
   platforms to report false breakages, which have been fixed.

 * Portability fix for a recent update to parse-options API.

 * "git help -a" did not work well when an overly long alias is
   defined, which has been corrected.

 * A recent update accidentally squelched an error message when the
   run_command API failed to run a missing command, which has been
   corrected.

Log message:
git: updated to 2.20.0

Git 2.20 Release Notes
======================

Backward Compatibility Notes
----------------------------

 * "git branch -l <foo>" used to be a way to ask a reflog to be
   created while creating a new branch, but that is no longer the
   case.  It is a short-hand for "git branch --list <foo>" now.

 * "git push" into refs/tags/* hierarchy is rejected without getting
   forced, but "git fetch" (misguidedly) used the "fast \ 
forwarding"
   rule used for the refs/heads/* hierarchy; this has been corrected,
   which means some fetches of tags that did not fail with older
   version of Git will fail without "--force" with this version.

 * "git help -a" now gives verbose output (same as "git help \ 
-av").
   Those who want the old output may say "git help --no-verbose -a"..

 * "git cpn --help", when "cpn" is an alias to, say, \ 
"cherry-pick -n",
   reported only the alias expansion of "cpn" in earlier versions of
   Git.  It now runs "git cherry-pick --help" to show the manual page
   of the command, while sending the alias expansion to the standard
   error stream.

 * "git send-email" learned to grab address-looking string on any
   trailer whose name ends with "-by". This is a backward-incompatible
   change.  Adding "--suppress-cc=misc-by" on the command line, or
   setting sendemail.suppresscc configuration variable to "misc-by",
   can be used to disable this behaviour.

Updates since v2.19
-------------------

UI, Workflows & Features

 * Running "git clone" against a project that contain two files with
   pathnames that differ only in cases on a case insensitive
   filesystem would result in one of the files lost because the
   underlying filesystem is incapable of holding both at the same
   time.  An attempt is made to detect such a case and warn.

 * "git checkout -b newbranch [HEAD]" should not have to do as much as
   checking out a commit different from HEAD.  An attempt is made to
   optimize this special case.

 * "git rev-list --stdin </dev/null" used to be an error; it now shows
   no output without an error.  "git rev-list --stdin --default HEAD"
   still falls back to the given default when nothing is given on the
   standard input.

 * Lift code from GitHub to restrict delta computation so that an
   object that exists in one fork is not made into a delta against
   another object that does not appear in the same forked repository.

 * "git format-patch" learned new "--interdiff" and \ 
"--range-diff"
   options to explain the difference between this version and the
   previous attempt in the cover letter (or after the three-dashes as
   a comment).

 * "git mailinfo" used in "git am" learned to make a best-effort
   recovery of a patch corrupted by MUA that sends text/plain with
   format=flawed option.
   (merge 3aa4d81f88 rs/mailinfo-format-flowed later to maint).

 * The rules used by "git push" and "git fetch" to determine \ 
if a ref
   can or cannot be updated were inconsistent; specifically, fetching
   to update existing tags were allowed even though tags are supposed
   to be unmoving anchoring points.  "git fetch" was taught to forbid
   updates to existing tags without the "--force" option.

 * "git multi-pack-index" learned to detect corruption in the .midx
   file it uses, and this feature has been integrated into "git fsck".

 * Generation of (experimental) commit-graph files have so far been
   fairly silent, even though it takes noticeable amount of time in a
   meaningfully large repository.  The users will now see progress
   output.

 * The minimum version of Windows supported by Windows port of Git is
   now set to Vista.

 * The completion script (in contrib/) learned to complete a handful of
   options "git stash list" command takes.

 * The completion script (in contrib/) learned that "git fetch
   --multiple" only takes remote names as arguments and no refspecs.

 * "git status" learns to show progress bar when refreshing the index
   takes a long time.
   (merge ae9af12287 nd/status-refresh-progress later to maint).

 * "git help -a" and "git help -av" give different pieces of
   information, and generally the "verbose" version is more friendly
   to the new users.  "git help -a" by default now uses the more
   verbose output (with "--no-verbose", you can go back to the
   original).  Also "git help -av" now lists aliases and external
   commands, which it did not used to.

 * Unlike "grep", "git grep" by default recurses to the \ 
whole tree.
   The command learned "git grep --recursive" option, so that "git
   grep --no-recursive" can serve as a synonym to setting the
   max-depth to 0.

 * When pushing into a repository that borrows its objects from an
   alternate object store, "git receive-pack" that responds to the
   push request on the other side lists the tips of refs in the
   alternate to reduce the amount of objects transferred.  This
   sometimes is detrimental when the number of refs in the alternate
   is absurdly large, in which case the bandwidth saved in potentially
   fewer objects transferred is wasted in excessively large ref
   advertisement.  The alternate refs that are advertised are now
   configurable with a pair of configuration variables.

 * "git cmd --help" when "cmd" is aliased used to only say \ 
"cmd is
   aliased to ...".  Now it shows that to the standard error stream
   and runs "git $cmd --help" where $cmd is the first word of the
   alias expansion.

 * The documentation of "git gc" has been updated to mention that it
   is no longer limited to "pruning away crufts" but also updates
   ancillary files like commit-graph as a part of repository
   optimization.

 * "git p4 unshelve" improvements.

 * The logic to select the default user name and e-mail on Windows has
   been improved.
   (merge 501afcb8b0 js/mingw-default-ident later to maint).

 * The "rev-list --filter" feature learned to exclude all trees via
   "tree:0" filter.

 * "git send-email" learned to grab address-looking string on any
   trailer whose name ends with "-by"; --suppress-cc=misc-by on the
   command line, or setting sendemail.suppresscc configuration
   variable to "misc-by", can be used to disable this behaviour.

 * "git mergetool" learned to take the "--[no-]gui" option, \ 
just like
   "git difftool" does.

 * "git rebase -i" learned a new insn, 'break', that the user can
   insert in the to-do list.  Upon hitting it, the command returns
   control back to the user.

 * New "--pretty=format:" placeholders %GF and %GP that show the GPG
   key fingerprints have been invented.

 * On platforms with recent cURL library, http.sslBackend configuration
   variable can be used to choose a different SSL backend at runtime.
   The Windows port uses this mechanism to switch between OpenSSL and
   Secure Channel while talking over the HTTPS protocol.

 * "git send-email" learned to disable SMTP authentication via the
   "--smtp-auth=none" option, even when the smtp username is given
   (which turns the authentication on by default).

 * A fourth class of configuration files (in addition to the
   traditional "system wide", "per user in the $HOME \ 
directory" and
   "per repository in the $GIT_DIR/config") has been introduced so
   that different worktrees that share the same repository (hence the
   same $GIT_DIR/config file) can use different customization.

 * A pattern with '**' that does not have a slash on either side used
   to be an invalid one, but the code now treats such double-asterisks
   the same way as two normal asterisks that happen to be adjacent to
   each other.
   (merge e5bbe09e88 nd/wildmatch-double-asterisk later to maint).

 * The "--no-patch" option, which can be used to get a high-level
   overview without the actual line-by-line patch difference shown, of
   the "range-diff" command was earlier broken, which has been
   corrected.

 * The recently merged "rebase in C" has an escape hatch to use the
   scripted version when necessary, but it hasn't been documented,
   which has been corrected.

Performance, Internal Implementation, Development Support etc.

 * Developer builds now use -Wunused-function compilation option.

 * One of our CI tests to run with "unusual/experimental/random"
   settings now also uses commit-graph and midx.

 * When there are too many packfiles in a repository (which is not
   recommended), looking up an object in these would require
   consulting many pack .idx files; a new mechanism to have a single
   file that consolidates all of these .idx files is introduced.

 * "git submodule update" is getting rewritten piece-by-piece into C.

 * The code for computing history reachability has been shuffled,
   obtained a bunch of new tests to cover them, and then being
   improved.

 * The unpack_trees() API used in checking out a branch and merging
   walks one or more trees along with the index.  When the cache-tree
   in the index tells us that we are walking a tree whose flattened
   contents is known (i.e. matches a span in the index), as linearly
   scanning a span in the index is much more efficient than having to
   open tree objects recursively and listing their entries, the walk
   can be optimized, which has been done.

 * When creating a thin pack, which allows objects to be made into a
   delta against another object that is not in the resulting pack but
   is known to be present on the receiving end, the code learned to
   take advantage of the reachability bitmap; this allows the server
   to send a delta against a base beyond the "boundary" commit.

 * spatch transformation to replace boolean uses of !hashcmp() to
   newly introduced oideq() is added, and applied, to regain
   performance lost due to support of multiple hash algorithms.

 * Fix a bug in which the same path could be registered under multiple
   worktree entries if the path was missing (for instance, was removed
   manually).  Also, as a convenience, expand the number of cases in
   which --force is applicable.

 * Split Documentation/config.txt for easier maintenance.
   (merge 6014363f0b nd/config-split later to maint).

 * Test helper binaries clean-up.
   (merge c9a1f4161f nd/test-tool later to maint).

 * Various tests have been updated to make it easier to swap the
   hash function used for object identification.
   (merge ae0c89d41b bc/hash-independent-tests later to maint).

 * Update fsck.skipList implementation and documentation.
   (merge 371a655074 ab/fsck-skiplist later to maint).

 * An alias that expands to another alias has so far been forbidden,
   but now it is allowed to create such an alias.

 * Various test scripts have been updated for style and also correct
   handling of exit status of various commands.

 * "gc --auto" ended up calling exit(-1) upon error, which has been
   corrected to use exit(1).  Also the error reporting behaviour when
   daemonized has been updated to exit with zero status when stopping
   due to a previously discovered error (which implies there is no
   point running gc to improve the situation); we used to exit with
   failure in such a case.

 * Various codepaths in the core-ish part learned to work on an
   arbitrary in-core index structure, not necessarily the default
   instance "the_index".
   (merge b3c7eef9b0 nd/the-index later to maint).

 * Code clean-up in the internal machinery used by "git status" and
   "git commit --dry-run".
   (merge 73ba5d78b4 ss/wt-status-committable later to maint).

 * Some environment variables that control the runtime options of Git
   used during tests are getting renamed for consistency.
   (merge 4231d1ba99 bp/rename-test-env-var later to maint).

 * A pair of new extensions to the index file have been introduced.
   They allow the index file to be read in parallel for performance.

 * The oidset API was built on top of the oidmap API which in turn is
   on the hashmap API.  Replace the implementation to build on top of
   the khash API and gain performance.

 * Over some transports, fetching objects with an exact commit object
   name can be done without first seeing the ref advertisements.  The
   code has been optimized to exploit this.

 * In a partial clone that will lazily be hydrated from the
   originating repository, we generally want to avoid "does this
   object exist (locally)?" on objects that we deliberately omitted
   when we created the clone.  The cache-tree codepath (which is used
   to write a tree object out of the index) however insisted that the
   object exists, even for paths that are outside of the partial
   checkout area.  The code has been updated to avoid such a check.

 * To help developers, an EditorConfig file that attempts to follow
   the project convention has been added.
   (merge b548d698a0 bc/editorconfig later to maint).

 * The result of coverage test can be combined with "git blame" to
   check the test coverage of code introduced recently with a new
   'coverage-diff' tool (in contrib/).
   (merge 783faedd65 ds/coverage-diff later to maint).

 * An experiment to fuzz test a few areas, hopefully we can gain more
   coverage to various areas.

 * More codepaths are moving away from hardcoded hash sizes.

 * The way the Windows port figures out the current directory has been
   improved.

 * The way DLLs are loaded on the Windows port has been improved.

 * Some tests have been reorganized and renamed; "ls t/" now gives a
   better overview of what is tested for these scripts than before.

 * "git rebase" and "git rebase -i" have been reimplemented in C.

 * Windows port learned to use nano-second resolution file timestamps.

 * The overly large Documentation/config.txt file have been split into
   million little pieces.  This potentially allows each individual piece
   to be included into the manual page of the command it affects more easily.

 * Replace three string-list instances used as look-up tables in "git
   fetch" with hashmaps.

 * Unify code to read the author-script used in "git am" and the
   commands that use the sequencer machinery, e.g. "git rebase -i".

 * In preparation to the day when we can deprecate and remove the
   "rebase -p", make sure we can skip and later remove tests for
   it.

 * The history traversal used to implement the tag-following has been
   optimized by introducing a new helper.

 * The helper function to refresh the cached stat information in the
   in-core index has learned to perform the lstat() part of the
   operation in parallel on multi-core platforms.

 * The code to traverse objects for reachability, used to decide what
   objects are unreferenced and expendable, have been taught to also
   consider per-worktree refs of other worktrees as starting points to
   prevent data loss.

 * "git add" needs to internally run "diff-files" \ 
equivalent, and the
   codepath learned the same optimization as "diff-files" has to run
   lstat(2) in parallel to find which paths have been updated in the
   working tree.

 * The procedure to install dependencies before testing at Travis CI
   is getting revamped for both simplicity and flexibility, taking
   advantage of the recent move to the vm-based environment.

 * The support for format-patch (and send-email) by the command-line
   completion script (in contrib/) has been simplified a bit.

 * The revision walker machinery learned to take advantage of the
   commit generation numbers stored in the commit-graph file.

 * The codebase has been cleaned up to reduce "#ifndef NO_PTHREADS".

 * The way -lcurl library gets linked has been simplified by taking
   advantage of the fact that we can just ask curl-config command how.

 * Various functions have been audited for "-Wunused-parameter" warnings
   and bugs in them got fixed.

 * A sanity check for start-up sequence has been added in the config
   API codepath.

 * The build procedure to link for fuzzing test has been made
   customizable with a new Makefile variable.

 * The way "git rebase" parses and forwards the command line options
   meant for underlying "git am" has been revamped, which fixed for
   options with parameters that were not passed correctly.

 * Our testing framework uses a special i18n "poisoned localization"
   feature to find messages that ought to stay constant but are
   incorrectly marked to be translated.  This feature has been made
   into a runtime option (it used to be a compile-time option).

 * "git push" used to check ambiguities between object-names and
   refnames while processing the list of refs' old and new values,
   which was unnecessary (as it knew that it is feeding raw object
   names).  This has been optimized out.

 * The xcurl_off_t() helper function is used to cast size_t to
   curl_off_t, but some compilers gave warnings against the code to
   ensure the casting is done without wraparound, when size_t is
   narrower than curl_off_t.  This warning has been squelched.

 * Code preparation to replace ulong vars with size_t vars where
   appropriate continues.

 * The "test installed Git" mode of our test suite has been updated to
   work better.

 * A coding convention around the Coccinelle semantic patches to have
   two classes to ease code migration process has been proposed and
   its support has been added to the Makefile.

 * The "container" mode of TravisCI is going away.  Our .travis.yml
   file is getting prepared for the transition.
   (merge 32ee384be8 ss/travis-ci-force-vm-mode later to maint).

 * Our test scripts can now take the '-V' option as a synonym for the
   '--verbose-log' option.
   (merge a5f52c6dab sg/test-verbose-log later to maint).

Fixes since v2.19
-----------------

 * "git interpret-trailers" and its underlying machinery had a buggy
   code that attempted to ignore patch text after commit log message,
   which triggered in various codepaths that will always get the log
   message alone and never get such an input.
   (merge 66e83d9b41 jk/trailer-fixes later to maint).

 * Malformed or crafted data in packstream can make our code attempt
   to read or write past the allocated buffer and abort, instead of
   reporting an error, which has been fixed.

 * "git rebase -i" did not clear the state files correctly when a run
   of "squash/fixup" is aborted and then the user manually amended the
   commit instead, which has been corrected.
   (merge 10d2f35436 js/rebase-i-autosquash-fix later to maint).

 * When fsmonitor is in use, after operation on submodules updates
   .gitmodules, we lost track of the fact that we did so and relied on
   stale fsmonitor data.
   (merge 43f1180814 bp/mv-submodules-with-fsmonitor later to maint).

 * Fix for a long-standing bug that leaves the index file corrupt when
   it shrinks during a partial commit.
   (merge 6c003d6ffb jk/reopen-tempfile-truncate later to maint).

 * Further fix for O_APPEND emulation on Windows
   (merge eeaf7ddac7 js/mingw-o-append later to maint).

 * A corner case bugfix in "git rerere" code.
   (merge ad2bf0d9b4 en/rerere-multi-stage-1-fix later to maint).

 * "git add ':(attr:foo)'" is not supported and is supposed to be
   rejected while the command line arguments are parsed, but we fail
   to reject such a command line upfront.
   (merge 84d938b732 nd/attr-pathspec-fix later to maint).

 * Recent update broke the reachability algorithm when refs (e.g.
   tags) that point at objects that are not commit were involved,
   which has been fixed.

 * "git rebase" etc. in Git 2.19 fails to abort when given an empty
   commit log message as result of editing, which has been corrected.
   (merge a3ec9eaf38 en/sequencer-empty-edit-result-aborts later to maint).

 * The code to backfill objects in lazily cloned repository did not
   work correctly, which has been corrected.
   (merge e68302011c jt/lazy-object-fetch-fix later to maint).

 * Update error messages given by "git remote" and make them consistent.
   (merge 5025425dff ms/remote-error-message-update later to maint).

 * "git update-ref" learned to make both "--no-deref" and \ 
"--stdin"
   work at the same time.
   (merge d345e9fbe7 en/update-ref-no-deref-stdin later to maint).

 * Recently added "range-diff" had a corner-case bug to cause it
   segfault, which has been corrected.
   (merge e467a90c7a tg/range-diff-corner-case-fix later to maint).

 * The recently introduced commit-graph auxiliary data is incompatible
   with mechanisms such as replace & grafts that "breaks" immutable
   nature of the object reference relationship.  Disable optimizations
   based on its use (and updating existing commit-graph) when these
   incompatible features are in use in the repository.
   (merge 829a321569 ds/commit-graph-with-grafts later to maint).

 * The mailmap file update.
   (merge 255eb03edf jn/mailmap-update later to maint).

 * The code in "git status" sometimes hit an assertion failure.  This
   was caused by a structure that was reused without cleaning the data
   used for the first run, which has been corrected.
   (merge 3e73cc62c0 en/status-multiple-renames-to-the-same-target-fix later to \ 
maint).

 * "git fetch $repo $object" in a partial clone did not correctly
   fetch the asked-for object that is referenced by an object in
   promisor packfile, which has been fixed.

 * A corner-case bugfix.
   (merge c5cbb27cb5 sm/show-superproject-while-conflicted later to maint).

 * Various fixes to "diff --color-moved-ws".

 * A partial clone that is configured to lazily fetch missing objects
   will on-demand issue a "git fetch" request to the originating
   repository to fill not-yet-obtained objects.  The request has been
   optimized for requesting a tree object (and not the leaf blob
   objects contained in it) by telling the originating repository that
   no blobs are needed.
   (merge 4c7f9567ea jt/non-blob-lazy-fetch later to maint).

 * The codepath to support the experimental split-index mode had
   remaining "racily clean" issues fixed.
   (merge 4c490f3d32 sg/split-index-racefix later to maint).

 * "git log --graph" showing an octopus merge sometimes miscounted the
   number of display columns it is consuming to show the merge and its
   parent commits, which has been corrected.
   (merge 04005834ed np/log-graph-octopus-fix later to maint).

 * "git range-diff" did not work well when the compared ranges had
   changes in submodules and the "--submodule=log" was used.

 * The implementation of run_command() API on the UNIX platforms had a
   bug that caused a command not on $PATH to be found in the current
   directory.
   (merge f67b980771 jk/run-command-notdot later to maint).

 * A mutex used in "git pack-objects" were not correctly initialized
   and this caused "git repack" to dump core on Windows.
   (merge 34204c8166 js/pack-objects-mutex-init-fix later to maint).

 * Under certain circumstances, "git diff D:/a/b/c D:/a/b/d" on
   Windows would strip initial parts from the paths because they
   were not recognized as absolute, which has been corrected.
   (merge ffd04e92e2 js/diff-notice-has-drive-prefix later to maint).

 * The receive.denyCurrentBranch=updateInstead codepath kicked in even
   when the push should have been rejected due to other reasons, such
   as it does not fast-forward or the update-hook rejects it, which
   has been corrected.
   (merge b072a25fad jc/receive-deny-current-branch-fix later to maint).

 * The logic to determine the archive type "git archive" uses did not
   correctly kick in for "git archive --remote", which has been
   corrected.

 * "git repack" in a shallow clone did not correctly update the
   shallow points in the repository, leading to a repository that
   does not pass fsck.
   (merge 5dcfbf564c js/shallow-and-fetch-prune later to maint).

 * Some codepaths failed to form a proper URL when .gitmodules record
   the URL to a submodule repository as relative to the repository of
   superproject, which has been corrected.
   (merge e0a862fdaf sb/submodule-url-to-absolute later to maint).

 * "git fetch" over protocol v2 into a shallow repository failed to
   fetch full history behind a new tip of history that was diverged
   before the cut-off point of the history that was previously fetched
   shallowly.

 * The command line completion machinery (in contrib/) has been
   updated to allow the completion script to tweak the list of options
   that are reported by the parse-options machinery correctly.
   (merge 276b49ff34 nd/completion-negation later to maint).

 * Operations on promisor objects make sense in the context of only a
   small subset of the commands that internally use the revisions
   machinery, but the "--exclude-promisor-objects" option were taken
   and led to nonsense results by commands like "log", to which it
   didn't make much sense.  This has been corrected.
   (merge 669b1d2aae md/exclude-promisor-objects-fix later to maint).

 * A regression in Git 2.12 era made "git fsck" fall into an infinite
   loop while processing truncated loose objects.
   (merge 18ad13e5b2 jk/detect-truncated-zlib-input later to maint).

 * "git ls-remote $there foo" was broken by recent update for the
   protocol v2 and stopped showing refs that match 'foo' that are not
   refs/{heads,tags}/foo, which has been fixed.
   (merge 6a139cdd74 jk/proto-v2-ref-prefix-fix later to maint).

 * Additional comment on a tricky piece of code to help developers.
   (merge 0afbe3e806 jk/stream-pack-non-delta-clarification later to maint).

 * A couple of tests used to leave the repository in a state that is
   deliberately corrupt, which have been corrected.
   (merge aa984dbe5e ab/pack-tests-cleanup later to maint).

 * The submodule support has been updated to read from the blob at
   HEAD:.gitmodules when the .gitmodules file is missing from the
   working tree.
   (merge 2b1257e463 ao/submodule-wo-gitmodules-checked-out later to maint).

 * "git fetch" was a bit loose in parsing responses from the other side
   when talking over the protocol v2.

 * "git rev-parse --exclude=* --branches --branches"  (i.e. first
   saying "add only things that do not match '*' out of all branches"
   and then adding all branches, without any exclusion this time)
   worked as expected, but "--exclude=* --all --all" did not work the
   same way, which has been fixed.
   (merge 5221048092 ag/rev-parse-all-exclude-fix later to maint).

 * "git send-email --transfer-encoding=..." in recent versions of Git
   sometimes produced an empty "Content-Transfer-Encoding:" header,
   which has been corrected.
   (merge 3c88e46f1a al/send-email-auto-cte-fixup later to maint).

 * The interface into "xdiff" library used to discover the offset and
   size of a generated patch hunk by first formatting it into the
   textual hunk header "@@ -n,m +k,l @@" and then parsing the numbers
   out.  A new interface has been introduced to allow callers a more
   direct access to them.
   (merge 5eade0746e jk/xdiff-interface later to maint).

 * Pathspec matching against a tree object were buggy when negative
   pathspec elements were involved, which has been fixed.
   (merge b7845cebc0 nd/tree-walk-path-exclusion later to maint).

 * "git merge" and "git pull" that merges into an unborn \ 
branch used
   to completely ignore "--verify-signatures", which has been
   corrected.
   (merge 01a31f3bca jk/verify-sig-merge-into-void later to maint).

 * "git rebase --autostash" did not correctly re-attach the HEAD at times.

 * "rev-parse --exclude=<pattern> --branches=<pattern>" \ 
etc. did not
   quite work, which has been corrected.
   (merge 9ab9b5df0e ra/rev-parse-exclude-glob later to maint).

 * When editing a patch in a "git add -i" session, a hunk could be
   made to no-op.  The "git apply" program used to reject a patch with
   such a no-op hunk to catch user mistakes, but it is now updated to
   explicitly allow a no-op hunk in an edited patch.
   (merge 22cb3835b9 js/apply-recount-allow-noop later to maint).

 * The URL to an MSDN page in a comment has been updated.
   (merge 2ef2ae2917 js/mingw-msdn-url later to maint).

 * "git ls-remote --sort=<thing>" can feed an object that is not yet
   available into the comparison machinery and segfault, which has
   been corrected to check such a request upfront and reject it.

 * When "git bundle" aborts due to an empty commit ranges
   (i.e. resulting in an empty pack), it left a file descriptor to an
   lockfile open, which resulted in leftover lockfile on Windows where
   you cannot remove a file with an open file descriptor.  This has
   been corrected.
   (merge 2c8ee1f53c jk/close-duped-fd-before-unlock-for-bundle later to maint).

 * "git format-patch --stat=<width>" can be used to specify the width
   used by the diffstat (shown in the cover letter).
   (merge 284aeb7e60 nd/format-patch-cover-letter-stat-width later to maint).

 * The way .git/index and .git/sharedindex* files were initially
   created gave these files different perm bits until they were
   adjusted for shared repository settings.  This was made consistent.
   (merge c9d6c78870 cc/shared-index-permbits later to maint).

 * "git rebase --stat" to transplant a piece of history onto a totally
   unrelated history were not working before and silently showed wrong
   result.  With the recent reimplementation in C, it started to instead
   die with an error message, as the original logic was not prepared
   to cope with this case.  This has now been fixed.

 * The advice message to tell the user to migrate an existing graft
   file to the replace system when a graft file was read was shown
   even when "git replace --convert-graft-file" command, which is the
   way the message suggests to use, was running, which made little
   sense.
   (merge 8821e90a09 ab/replace-graft-with-replace-advice later to maint).

 * "git diff --raw" lost ellipses to adjust the output columns for
   some time now, but the documentation still showed them.

 * Code cleanup, docfix, build fix, etc.

Log message:
git: Update devel/git to 2.19.2

Changes:
Git v2.19.2 Release Notes
=========================
Fixes since v2.19.1
-------------------

 * "git interpret-trailers" and its underlying machinery had a buggy
   code that attempted to ignore patch text after commit log message,
   which triggered in various codepaths that will always get the log
   message alone and never get such an input.

 * "git rebase -i" did not clear the state files correctly when a run
   of "squash/fixup" is aborted and then the user manually amended the
   commit instead, which has been corrected.

 * When fsmonitor is in use, after operation on submodules updates
   .gitmodules, we lost track of the fact that we did so and relied on
   stale fsmonitor data.

 * Fix for a long-standing bug that leaves the index file corrupt when
   it shrinks during a partial commit.

 * Further fix for O_APPEND emulation on Windows

 * A corner case bugfix in "git rerere" code.

 * "git add ':(attr:foo)'" is not supported and is supposed to be
   rejected while the command line arguments are parsed, but we fail
   to reject such a command line upfront.

 * "git rebase" etc. in Git 2.19 fails to abort when given an empty
   commit log message as result of editing, which has been corrected.

 * The code to backfill objects in lazily cloned repository did not
   work correctly, which has been corrected.

 * Update error messages given by "git remote" and make them consistent.

 * "git update-ref" learned to make both "--no-deref" and \ 
"--stdin"
   work at the same time.

 * Recently added "range-diff" had a corner-case bug to cause it
   segfault, which has been corrected.

 * The recently introduced commit-graph auxiliary data is incompatible
   with mechanisms such as replace & grafts that "breaks" immutable
   nature of the object reference relationship.  Disable optimizations
   based on its use (and updating existing commit-graph) when these
   incompatible features are in use in the repository.

 * The mailmap file update.

 * The code in "git status" sometimes hit an assertion failure.  This
   was caused by a structure that was reused without cleaning the data
   used for the first run, which has been corrected.

 * A corner-case bugfix.

 * A partial clone that is configured to lazily fetch missing objects
   will on-demand issue a "git fetch" request to the originating
   repository to fill not-yet-obtained objects.  The request has been
   optimized for requesting a tree object (and not the leaf blob
   objects contained in it) by telling the originating repository that
   no blobs are needed.

 * The codepath to support the experimental split-index mode had
   remaining "racily clean" issues fixed.

 * "git log --graph" showing an octopus merge sometimes miscounted the
   number of display columns it is consuming to show the merge and its
   parent commits, which has been corrected.

 * The implementation of run_command() API on the UNIX platforms had a
   bug that caused a command not on $PATH to be found in the current
   directory.

 * A mutex used in "git pack-objects" were not correctly initialized
   and this caused "git repack" to dump core on Windows.

 * Under certain circumstances, "git diff D:/a/b/c D:/a/b/d" on
   Windows would strip initial parts from the paths because they
   were not recognized as absolute, which has been corrected.

 * The receive.denyCurrentBranch=updateInstead codepath kicked in even
   when the push should have been rejected due to other reasons, such
   as it does not fast-forward or the update-hook rejects it, which
   has been corrected.

 * "git repack" in a shallow clone did not correctly update the
   shallow points in the repository, leading to a repository that
   does not pass fsck.

 * Operations on promisor objects make sense in the context of only a
   small subset of the commands that internally use the revisions
   machinery, but the "--exclude-promisor-objects" option were taken
   and led to nonsense results by commands like "log", to which it
   didn't make much sense.  This has been corrected.

 * The "container" mode of TravisCI is going away.  Our .travis.yml
   file is getting prepared for the transition.

 * Our test scripts can now take the '-V' option as a synonym for the
   '--verbose-log' option.

 * A regression in Git 2.12 era made "git fsck" fall into an infinite
   loop while processing truncated loose objects.

Also contains various documentation updates and code clean-ups.

Log message:
Git: update to 2.19.1

These releases fix a security flaw (CVE-2018-17456), which allowed an
attacker to execute arbitrary code by crafting a malicious .gitmodules
file in a project cloned with --recurse-submodules.

When running "git clone --recurse-submodules", Git parses the supplied
.gitmodules file for a URL field and blindly passes it as an argument
to a "git clone" subprocess.  If the URL field is set to a string that
begins with a dash, this "git clone" subprocess interprets the URL as
an option.  This can lead to executing an arbitrary script shipped in
the superproject as the user who ran "git clone".

In addition to fixing the security issue for the user running "clone",
the 2.17.2, 2.18.1 and 2.19.1 releases have an "fsck" check which can
be used to detect such malicious repository content when fetching or
accepting a push. See "transfer.fsckObjects" in git-config(1).

Credit for finding and fixing this vulnerability goes to joernchen
and Jeff King, respectively.

Log message:
git: updated to 2.19.0

Git 2.19 Release Notes

Updates since v2.18
-------------------

UI, Workflows & Features

 * "git diff" compares the index and the working tree.  For paths
   added with intent-to-add bit, the command shows the full contents
   of them as added, but the paths themselves were not marked as new
   files.  They are now shown as new by default.

   "git apply" learned the "--intent-to-add" option so that an
   otherwise working-tree-only application of a patch will add new
   paths to the index marked with the "intent-to-add" bit.

 * "git grep" learned the "--column" option that gives not \ 
just the
   line number but the column number of the hit.

 * The "-l" option in "git branch -l" is an unfortunate \ 
short-hand for
   "--create-reflog", but many users, both old and new, somehow expect
   it to be something else, perhaps "--list".  This step warns when \ 
"-l"
   is used as a short-hand for "--create-reflog" and warns about the
   future repurposing of the it when it is used.

 * The userdiff pattern for .php has been updated.

 * The content-transfer-encoding of the message "git send-email" sends
   out by default was 8bit, which can cause trouble when there is an
   overlong line to bust RFC 5322/2822 limit.  A new option 'auto' to
   automatically switch to quoted-printable when there is such a line
   in the payload has been introduced and is made the default.

 * "git checkout" and "git worktree add" learned to honor
   checkout.defaultRemote when auto-vivifying a local branch out of a
   remote tracking branch in a repository with multiple remotes that
   have tracking branches that share the same names.
   (merge 8d7b558bae ab/checkout-default-remote later to maint).

 * "git grep" learned the "--only-matching" option.

 * "git rebase --rebase-merges" mode now handles octopus merges as
   well.

 * Add a server-side knob to skip commits in exponential/fibbonacci
   stride in an attempt to cover wider swath of history with a smaller
   number of iterations, potentially accepting a larger packfile
   transfer, instead of going back one commit a time during common
   ancestor discovery during the "git fetch" transaction.
   (merge 42cc7485a2 jt/fetch-negotiator-skipping later to maint).

 * A new configuration variable core.usereplacerefs has been added,
   primarily to help server installations that want to ignore the
   replace mechanism altogether.

 * Teach "git tag -s" etc. a few configuration variables (gpg.format
   that can be set to "openpgp" or "x509", and \ 
gpg.<format>.program
   that is used to specify what program to use to deal with the format)
   to allow x.509 certs with CMS via "gpgsm" to be used instead of
   openpgp via "gnupg".

 * Many more strings are prepared for l10n.

 * "git p4 submit" learns to ask its own pre-submit hook if it should
   continue with submitting.

 * The test performed at the receiving end of "git push" to prevent
   bad objects from entering repository can be customized via
   receive.fsck.* configuration variables; we now have gained a
   counterpart to do the same on the "git fetch" side, with
   fetch.fsck.* configuration variables.

 * "git pull --rebase=interactive" learned "i" as a \ 
short-hand for
   "interactive".

 * "git instaweb" has been adjusted to run better with newer Apache on
   RedHat based distros.

 * "git range-diff" is a reimplementation of "git tbdiff" \ 
that lets us
   compare individual patches in two iterations of a topic.

 * The sideband code learned to optionally paint selected keywords at
   the beginning of incoming lines on the receiving end.

 * "git branch --list" learned to take the default sort order from the
   'branch.sort' configuration variable, just like "git tag --list"
   pays attention to 'tag.sort'.

 * "git worktree" command learned "--quiet" option to make \ 
it less
   verbose.

Performance, Internal Implementation, Development Support etc.

 * The bulk of "git submodule foreach" has been rewritten in C.

 * The in-core "commit" object had an all-purpose "void \ 
*util" field,
   which was tricky to use especially in library-ish part of the
   code.  All of the existing uses of the field has been migrated to a
   more dedicated "commit-slab" mechanism and the field is eliminated.

 * A less often used command "git show-index" has been modernized.
   (merge fb3010c31f jk/show-index later to maint).

 * The conversion to pass "the_repository" and then \ 
"a_repository"
   throughout the object access API continues.

 * Continuing with the idea to programatically enumerate various
   pieces of data required for command line completion, teach the
   codebase to report the list of configuration variables
   subcommands care about to help complete them.

 * Separate "rebase -p" codepath out of "rebase -i" \ 
implementation to
   slim down the latter and make it easier to manage.

 * Make refspec parsing codepath more robust.

 * Some flaky tests have been fixed.

 * Continuing with the idea to programmatically enumerate various
   pieces of data required for command line completion, the codebase
   has been taught to enumerate options prefixed with "--no-" to
   negate them.

 * Build and test procedure for netrc credential helper (in contrib/)
   has been updated.

 * Remove unused function definitions and declarations from ewah
   bitmap subsystem.

 * Code preparation to make "git p4" closer to be usable with Python 3.

 * Tighten the API to make it harder to misuse in-tree .gitmodules
   file, even though it shares the same syntax with configuration
   files, to read random configuration items from it.

 * "git fast-import" has been updated to avoid attempting to create
   delta against a zero-byte-long string, which is pointless.

 * The codebase has been updated to compile cleanly with -pedantic
   option.
   (merge 2b647a05d7 bb/pedantic later to maint).

 * The character display width table has been updated to match the
   latest Unicode standard.
   (merge 570951eea2 bb/unicode-11-width later to maint).

 * test-lint now looks for broken use of "VAR=VAL shell_func" in test
   scripts.

 * Conversion from uchar[40] to struct object_id continues.

 * Recent "security fix" to pay attention to contents of \ 
".gitmodules"
   while accepting "git push" was a bit overly strict than necessary,
   which has been adjusted.

 * "git fsck" learns to make sure the optional commit-graph file is in
   a sane state.

 * "git diff --color-moved" feature has further been tweaked.

 * Code restructuring and a small fix to transport protocol v2 during
   fetching.

 * Parsing of -L[<N>][,[<M>]] parameters "git blame" and \ 
"git log"
   take has been tweaked.

 * lookup_commit_reference() and friends have been updated to find
   in-core object for a specific in-core repository instance.

 * Various glitches in the heuristics of merge-recursive strategy have
   been documented in new tests.

 * "git fetch" learned a new option "--negotiation-tip" to \ 
limit the
   set of commits it tells the other end as "have", to reduce wasted
   bandwidth and cycles, which would be helpful when the receiving
   repository has a lot of refs that have little to do with the
   history at the remote it is fetching from.

 * For a large tree, the index needs to hold many cache entries
   allocated on heap.  These cache entries are now allocated out of a
   dedicated memory pool to amortize malloc(3) overhead.

 * Tests to cover various conflicting cases have been added for
   merge-recursive.

 * Tests to cover conflict cases that involve submodules have been
   added for merge-recursive.

 * Look for broken "&&" chains that are hidden in subshell, many of
   which have been found and corrected.

 * The singleton commit-graph in-core instance is made per in-core
   repository instance.

 * "make DEVELOPER=1 DEVOPTS=pedantic" allows developers to compile
   with -pedantic option, which may catch more problematic program
   constructs and potential bugs.

 * Preparatory code to later add json output for telemetry data has
   been added.

 * Update the way we use Coccinelle to find out-of-style code that
   need to be modernised.

 * It is too easy to misuse system API functions such as strcat();
   these selected functions are now forbidden in this codebase and
   will cause a compilation failure.

 * Add a script (in contrib/) to help users of VSCode work better with
   our codebase.

 * The Travis CI scripts were taught to ship back the test data from
   failed tests.
   (merge aea8879a6a sg/travis-retrieve-trash-upon-failure later to maint).

 * The parse-options machinery learned to refrain from enclosing
   placeholder string inside a "<bra" and "ket>" pair \ 
automatically
   without PARSE_OPT_LITERAL_ARGHELP.  Existing help text for option
   arguments that are not formatted correctly have been identified and
   fixed.
   (merge 5f0df44cd7 rs/parse-opt-lithelp later to maint).

 * Noiseword "extern" has been removed from function decls in the
   header files.

 * A few atoms like %(objecttype) and %(objectsize) in the format
   specifier of "for-each-ref --format=<format>" can be filled \ 
without
   getting the full contents of the object, but just with the object
   header.  These cases have been optimized by calling
   oid_object_info() API (instead of reading and inspecting the data).

 * The end result of documentation update has been made to be
   inspected more easily to help developers.

 * The API to iterate over all objects learned to optionally list
   objects in the order they appear in packfiles, which helps locality
   of access if the caller accesses these objects while as objects are
   enumerated.

 * Improve built-in facility to catch broken &&-chain in the tests.

 * The more library-ish parts of the codebase learned to work on the
   in-core index-state instance that is passed in by their callers,
   instead of always working on the singleton "the_index" instance.

 * A test prerequisite defined by various test scripts with slightly
   different semantics has been consolidated into a single copy and
   made into a lazily defined one.
   (merge 6ec633059a wc/make-funnynames-shared-lazy-prereq later to maint).

 * After a partial clone, repeated fetches from promisor remote would
   have accumulated many packfiles marked with .promisor bit without
   getting them coalesced into fewer packfiles, hurting performance.
   "git repack" now learned to repack them.

 * Partially revert the support for multiple hash functions to regain
   hash comparison performance; we'd think of a way to do this better
   in the next cycle.

 * "git help --config" (which is used in command line completion)
   missed the configuration variables not described in the main
   config.txt file but are described in another file that is included
   by it, which has been corrected.

 * The test linter code has learned that the end of here-doc mark
   "EOF" can be quoted in a double-quote pair, not just in a
   single-quote pair.

Log message:
git: updated to 2.18.0

2.18.0:

UI, Workflows & Features

 * Rename detection logic that is used in "merge" and \ 
"cherry-pick" has
   learned to guess when all of x/a, x/b and x/c have moved to z/a,
   z/b and z/c, it is likely that x/d added in the meantime would also
   want to move to z/d by taking the hint that the entire directory
   'x' moved to 'z'.  A bug causing dirty files involved in a rename
   to be overwritten during merge has also been fixed as part of this
   work.  Incidentally, this also avoids updating a file in the
   working tree after a (non-trivial) merge whose result matches what
   our side originally had.

 * "git filter-branch" learned to use a different exit code to allow
   the callers to tell the case where there was no new commits to
   rewrite from other error cases.

 * When built with more recent cURL, GIT_SSL_VERSION can now specify
   "tlsv1.3" as its value.

 * "git gui" learned that "~/.ssh/id_ecdsa.pub" and
   "~/.ssh/id_ed25519.pub" are also possible SSH key files.
   (merge 2e2f0288ef bb/git-gui-ssh-key-files later to maint).

 * "git gui" performs commit upon CTRL/CMD+ENTER but the
   CTRL/CMD+KP_ENTER (i.e. enter key on the numpad) did not have the
   same key binding.  It now does.
   (merge 28a1d94a06 bp/git-gui-bind-kp-enter later to maint).

 * "git gui" has been taught to work with old versions of tk (like
   8.5.7) that do not support "ttk::style theme use" as a way to query
   the current theme.
   (merge 4891961105 cb/git-gui-ttk-style later to maint).

 * "git rebase" has learned to honor "--signoff" option when \ 
using
   backends other than "am" (but not "--preserve-merges").

 * "git branch --list" during an interrupted "rebase -i" now lets
   users distinguish the case where a detached HEAD is being rebased
   and a normal branch is being rebased.

 * "git mergetools" learned talking to guiffy.

 * The scripts in contrib/emacs/ have outlived their usefulness and
   have been replaced with a stub that errors out and tells the user
   there are replacements.

 * The new "working-tree-encoding" attribute can ask Git to convert the
   contents to the specified encoding when checking out to the working
   tree (and the other way around when checking in).

 * The "git config" command uses separate options e.g. "--int",
   "--bool", etc. to specify what type the caller wants the value to
   be interpreted as.  A new "--type=<typename>" option has been
   introduced, which would make it cleaner to define new types.

 * "git config --get" learned the "--default" option, to help the
   calling script.  Building on top of the above changes, the
   "git config" learns "--type=color" type.  Taken together, \ 
you can
   do things like "git config --get foo.color --default blue" and get
   the ANSI color sequence for the color given to foo.color variable,
   or "blue" if the variable does not exist.

 * "git ls-remote" learned an option to allow sorting its output based
   on the refnames being shown.

 * The command line completion (in contrib/) has been taught that "git
   stash save" has been deprecated ("git stash push" is the preferred
   spelling in the new world) and does not offer it as a possible
   completion candidate when "git stash push" can be.

 * "git gc --prune=nonsense" spent long time repacking and then
   silently failed when underlying "git prune --expire=nonsense"
   failed to parse its command line.  This has been corrected.

 * Error messages from "git push" can be painted for more visibility.

 * "git http-fetch" (deprecated) had an optional and experimental
   "feature" to fetch only commits and/or trees, which nobody used.
   This has been removed.

 * The functionality of "$GIT_DIR/info/grafts" has been superseded by
   the "refs/replace/" mechanism for some time now, but the internal
   code had support for it in many places, which has been cleaned up
   in order to drop support of the "grafts" mechanism.

 * "git worktree add" learned to check out an existing branch.

 * "git --no-pager cmd" did not have short-and-sweet single letter
   option. Now it does as "-P".
   (merge 7213c28818 js/no-pager-shorthand later to maint).

 * "git rebase" learned "--rebase-merges" to transplant the whole
   topology of commit graph elsewhere.

 * "git status" learned to pay attention to UI related diff
   configuration variables such as diff.renames.

 * The command line completion mechanism (in contrib/) learned to load
   custom completion file for "git $command" where $command is a
   custom "git-$command" that the end user has on the $PATH when using
   newer version of bash-completion.

 * "git send-email" can sometimes offer confirmation dialog "Send this
   email?" with choices 'Yes', 'No', 'Quit', and 'All'.  A new action
   'Edit' has been added to this dialog's choice.

 * With merge.renames configuration set to false, the recursive merge
   strategy can be told not to spend cycles trying to find renamed
   paths and merge them accordingly.

 * "git status" learned to honor a new status.renames configuration to
   skip rename detection, which could be useful for those who want to
   do so without disabling the default rename detection done by the
   "git diff" command.

 * Command line completion (in contrib/) learned to complete pathnames
   for various commands better.

 * "git blame" learns to unhighlight uninteresting metadata from the
   originating commit on lines that are the same as the previous one,
   and also paint lines in different colors depending on the age of
   the commit.

 * Transfer protocol v2 learned to support the partial clone.

 * When a short hexadecimal string is used to name an object but there
   are multiple objects that share the string as the prefix of their
   names, the code lists these ambiguous candidates in a help message.
   These object names are now sorted according to their types for
   easier eyeballing.

 * "git fetch $there $refspec" that talks over protocol v2 can take
   advantage of server-side ref filtering; the code has been extended
   so that this mechanism triggers also when fetching with configured
   refspec.

 * Our HTTP client code used to advertise that we accept gzip encoding
   from the other side; instead, just let cURL library to advertise
   and negotiate the best one.

 * "git p4" learned to "unshelve" shelved commit from P4.
   (merge 123f631761 ld/p4-unshelve later to maint).

Log message:
git: updated to 2.17.1

Git v2.17.1:

Fixes:

 * This release contains the same fixes made in the v2.13.7 version of
   Git, covering CVE-2018-11233 and 11235, and forward-ported to
   v2.14.4, v2.15.2 and v2.16.4 releases.  See release notes to
   v2.13.7 for details.

 * In addition to the above fixes, this release has support on the
   server side to reject pushes to repositories that attempt to create
   such problematic .gitmodules file etc. as tracked contents, to help
   hosting sites protect their customers by preventing malicious
   contents from spreading.

Log message:
git: updated to 2.17.0

Git 2.17:

UI, Workflows & Features
* "diff" family of commands learned \ 
"--find-object=<object-id>" option
  to limit the findings to changes that involve the named object.
* "git format-patch" learned to give 72-cols to diffstat, which is
  consistent with other line length limits the subcommand uses for
  its output meant for e-mails.
* The log from "git daemon" can be redirected with a new option; one
  relevant use case is to send the log to standard error (instead of
  syslog) when running it from inetd.
* "git rebase" learned to take "--allow-empty-message" option.
* "git am" has learned the "--quit" option, in addition to the
  existing "--abort" option; having the pair mirrors a few other
  commands like "rebase" and "cherry-pick".
* "git worktree add" learned to run the post-checkout hook, just like
  "git clone" runs it upon the initial checkout.
* "git tag" learned an explicit "--edit" option that allows the
  message given via "-m" and "-F" to be further edited.
* "git fetch --prune-tags" may be used as a handy short-hand for
  getting rid of stale tags that are locally held.
* The new "--show-current-patch" option gives an end-user facing way
  to get the diff being applied when "git rebase" (and "git am")
  stops with a conflict.
* "git add -p" used to offer "/" (look for a matching hunk) as a
  choice, even there was only one hunk, which has been corrected.
  Also the single-key help is now given only for keys that are
  enabled (e.g. help for '/' won't be shown when there is only one
  hunk).
* Since Git 1.7.9, "git merge" defaulted to --no-ff (i.e. even when
  the side branch being merged is a descendant of the current commit,
  create a merge commit instead of fast-forwarding) when merging a
  tag object.  This was appropriate default for integrators who pull
  signed tags from their downstream contributors, but caused an
  unnecessary merges when used by downstream contributors who
  habitually "catch up" their topic branches with tagged releases
  from the upstream.  Update "git merge" to default to --no-ff only
  when merging a tag object that does *not* sit at its usual place in
  refs/tags/ hierarchy, and allow fast-forwarding otherwise, to
  mitigate the problem.
* "git status" can spend a lot of cycles to compute the relation
  between the current branch and its upstream, which can now be
  disabled with "--no-ahead-behind" option.
* "git diff" and friends learned funcname patterns for Go language
  source files.
* "git send-email" learned "--reply-to=<address>" option.
* Funcname pattern used for C# now recognizes "async" keyword.
* In a way similar to how "git tag" learned to honor the pager
  setting only in the list mode, "git config" learned to ignore the
  pager setting when it is used for setting values (i.e. when the
  purpose of the operation is not to "show").

Performance, Internal Implementation, Development Support etc.
* More perf tests for threaded grep
* "perf" test output can be sent to codespeed server.
* The build procedure for perl/ part has been greatly simplified by
  weaning ourselves off of MakeMaker.
* Perl 5.8 or greater has been required since Git 1.7.4 released in
  2010, but we continued to assume some core modules may not exist and
  used a conditional "eval { require <<module>> }"; we no \ 
longer do
  this.  Some platforms (Fedora/RedHat/CentOS, for example) ship Perl
  without all core modules by default (e.g. Digest::MD5, File::Temp,
  File::Spec, Net::Domain, Net::SMTP).  Users on such platforms may
  need to install these additional modules.
* As a convenience, we install copies of Perl modules we require which
  are not part of the core Perl distribution (e.g. Error and
  Mail::Address).  Users and packagers whose operating system provides
  these modules can set NO_PERL_CPAN_FALLBACKS to avoid installing the
  bundled modules.
* In preparation for implementing narrow/partial clone, the machinery
  for checking object connectivity used by gc and fsck has been
  taught that a missing object is OK when it is referenced by a
  packfile specially marked as coming from trusted repository that
  promises to make them available on-demand and lazily.
* The machinery to clone & fetch, which in turn involves packing and
  unpacking objects, has been told how to omit certain objects using
  the filtering mechanism introduced by another topic.  It now knows
  to mark the resulting pack as a promisor pack to tolerate missing
  objects, laying foundation for "narrow" clones.
* The first step to getting rid of mru API and using the
  doubly-linked list API directly instead.
* Retire mru API as it does not give enough abstraction over
  underlying list API to be worth it.
* Rewrite two more "git submodule" subcommands in C.
* The tracing machinery learned to report tweaking of environment
  variables as well.
* Update Coccinelle rules to catch and optimize strbuf_addf(&buf, \ 
"%s", str)
* Prevent "clang-format" from breaking line after function return type.
* The sequencer infrastructure is shared across "git cherry-pick",
  "git rebase -i", etc., and has always spawned "git commit" \ 
when it
  needs to create a commit.  It has been taught to do so internally,
  when able, by reusing the codepath "git commit" itself uses, which
  gives performance boost for a few tens of percents in some sample
  scenarios.
* Push the submodule version of collision-detecting SHA-1 hash
  implementation a bit harder on builders.
* Avoid mmapping small files while using packed refs (especially ones
  with zero size, which would cause later munmap() to fail).
* Conversion from uchar[20] to struct object_id continues.
* More tests for wildmatch functions.
* The code to binary search starting from a fan-out table (which is
  how the packfile is indexed with object names) has been refactored
  into a reusable helper.
* We now avoid using identifiers that clash with C++ keywords.  Even
  though it is not a goal to compile Git with C++ compilers, changes
  like this help use of code analysis tools that targets C++ on our
  codebase.
* The executable is now built in 'script' phase in Travis CI integration,
  to follow the established practice, rather than during 'before_script'
  phase.  This allows the CI categorize the failures better ('failed'
  is project's fault, 'errored' is build environment's).
* Writing out the index file when the only thing that changed in it
  is the untracked cache information is often wasteful, and this has
  been optimized out.
* Various pieces of Perl code we have have been cleaned up.
* Internal API clean-up to allow write_locked_index() optionally skip
  writing the in-core index when it is not modified.

Log message:
git: updated to 2.16.3

Git v2.16.3 Release Notes

* "git status" after moving a path in the working tree (hence making
  it appear "removed") and then adding with the -N option (hence
  making that appear "added") detected it as a rename, but did not
  report the  old and new pathnames correctly.

* "git commit --fixup" did not allow "-m<message>" \ 
option to be used
  at the same time; allow it to annotate resulting commit with more
  text.

* When resetting the working tree files recursively, the working tree
  of submodules are now also reset to match.

* Fix for a commented-out code to adjust it to a rather old API change
  around object ID.

* When there are too many changed paths, "git diff" showed a warning
  message but in the middle of a line.

* The http tracing code, often used to debug connection issues,
  learned to redact potentially sensitive information from its output
  so that it can be more safely sharable.

* Crash fix for a corner case where an error codepath tried to unlock
  what it did not acquire lock on.

* The split-index mode had a few corner case bugs fixed.

* Assorted fixes to "git daemon".

* Completion of "git merge -s<strategy>" (in contrib/) did not work
  well in non-C locale.

* Workaround for segfault with more recent versions of SVN.

* Recently introduced leaks in fsck have been plugged.

* Travis CI integration now builds the executable in 'script' phase
  to follow the established practice, rather than during
  'before_script' phase.  This allows the CI categorize the failures
  better ('failed' is project's fault, 'errored' is build
  environment's).

Log message:
git: updated to 2.16.2

Git v2.16.2 Release Notes

Fixes since v2.16.1

 * An old regression in "git describe --all $annotated_tag^0" has been
   fixed.

 * "git svn dcommit" did not take into account the fact that a
   svn+ssh:// URL with a username@ (typically used for pushing) refers
   to the same SVN repository without the username@ and failed when
   svn.pushmergeinfo option is set.

 * "git merge -Xours/-Xtheirs" learned to use our/their version when
   resolving a conflicting updates to a symbolic link.

 * "git clone $there $here" is allowed even when here directory exists
   as long as it is an empty directory, but the command incorrectly
   removed it upon a failure of the operation.

 * "git stash -- <pathspec>" incorrectly blew away untracked files in
   the directory that matched the pathspec, which has been corrected.

 * "git add -p" was taught to ignore local changes to submodules as
   they do not interfere with the partial addition of regular changes
   anyway.