merge(third_party/git): Merge squashed git subtree at v2.23.0 r/373

Merge commit '1b593e1ea4d2af0f6444d9a7788d5d99abd6fde5' as 'third_party/git'

1 files changed, 508 insertions, 0 deletions

diff --git a/third_party/git/Documentation/RelNotes/2.15.0.txt b/third_party/git/Documentation/RelNotes/2.15.0.txt
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+Git 2.15 Release Notes
+======================
+
+Backward compatibility notes and other notable changes.
+
+ * Use of an empty string as a pathspec element that is used for
+   'everything matches' is still warned and Git asks users to use a
+   more explicit '.' for that instead.  The hope is that existing
+   users will not mind this change, and eventually the warning can be
+   turned into a hard error, upgrading the deprecation into removal of
+   this (mis)feature.  That is now scheduled to happen in Git v2.16,
+   the next major release after this one.
+
+ * Git now avoids blindly falling back to ".git" when the setup
+   sequence said we are _not_ in Git repository.  A corner case that
+   happens to work right now may be broken by a call to BUG().
+   We've tried hard to locate such cases and fixed them, but there
+   might still be cases that need to be addressed--bug reports are
+   greatly appreciated.
+
+ * "branch --set-upstream" that has been deprecated in Git 1.8 has
+   finally been retired.
+
+
+Updates since v2.14
+-------------------
+
+UI, Workflows & Features
+
+ * An example that is now obsolete has been removed from a sample hook,
+   and an old example in it that added a sign-off manually has been
+   improved to use the interpret-trailers command.
+
+ * The advice message given when "git rebase" stops for conflicting
+   changes has been improved.
+
+ * The "rerere-train" script (in contrib/) learned the "--overwrite"
+   option to allow overwriting existing recorded resolutions.
+
+ * "git contacts" (in contrib/) now lists the address on the
+   "Reported-by:" trailer to its output, in addition to those on
+   S-o-b: and other trailers, to make it easier to notify (and thank)
+   the original bug reporter.
+
+ * "git rebase", especially when it is run by mistake and ends up
+   trying to replay many changes, spent long time in silence.  The
+   command has been taught to show progress report when it spends
+   long time preparing these many changes to replay (which would give
+   the user a chance to abort with ^C).
+
+ * "git merge" learned a "--signoff" option to add the Signed-off-by:
+   trailer with the committer's name.
+
+ * "git diff" learned to optionally paint new lines that are the same
+   as deleted lines elsewhere differently from genuinely new lines.
+
+ * "git interpret-trailers" learned to take the trailer specifications
+   from the command line that overrides the configured values.
+
+ * "git interpret-trailers" has been taught a "--parse" and a few
+   other options to make it easier for scripts to grab existing
+   trailer lines from a commit log message.
+
+ * The "--format=%(trailers)" option "git log" and its friends take
+   learned to take the 'unfold' and 'only' modifiers to normalize its
+   output, e.g. "git log --format=%(trailers:only,unfold)".
+
+ * "gitweb" shows a link to visit the 'raw' contents of blobs in the
+   history overview page.
+
+ * "[gc] rerereResolved = 5.days" used to be invalid, as the variable
+   is defined to take an integer counting the number of days.  It now
+   is allowed.
+
+ * The code to acquire a lock on a reference (e.g. while accepting a
+   push from a client) used to immediately fail when the reference is
+   already locked---now it waits for a very short while and retries,
+   which can make it succeed if the lock holder was holding it during
+   a read-only operation.
+
+ * "branch --set-upstream" that has been deprecated in Git 1.8 has
+   finally been retired.
+
+ * The codepath to call external process filter for smudge/clean
+   operation learned to show the progress meter.
+
+ * "git rev-parse" learned "--is-shallow-repository", that is to be
+   used in a way similar to existing "--is-bare-repository" and
+   friends.
+
+ * "git describe --match <pattern>" has been taught to play well with
+   the "--all" option.
+
+ * "git branch" learned "-c/-C" to create a new branch by copying an
+   existing one.
+
+ * Some commands (most notably "git status") makes an opportunistic
+   update when performing a read-only operation to help optimize later
+   operations in the same repository.  The new "--no-optional-locks"
+   option can be passed to Git to disable them.
+
+ * "git for-each-ref --format=..." learned a new format element,
+   %(trailers), to show only the commit log trailer part of the log
+   message.
+
+
+Performance, Internal Implementation, Development Support etc.
+
+ * Conversion from uchar[20] to struct object_id continues.
+
+ * Start using selected c99 constructs in small, stable and
+   essential part of the system to catch people who care about
+   older compilers that do not grok them.
+
+ * The filter-process interface learned to allow a process with long
+   latency give a "delayed" response.
+
+ * Many uses of comparison callback function the hashmap API uses
+   cast the callback function type when registering it to
+   hashmap_init(), which defeats the compile time type checking when
+   the callback interface changes (e.g. gaining more parameters).
+   The callback implementations have been updated to take "void *"
+   pointers and cast them to the type they expect instead.
+
+ * Because recent Git for Windows do come with a real msgfmt, the
+   build procedure for git-gui has been updated to use it instead of a
+   hand-rolled substitute.
+
+ * "git grep --recurse-submodules" has been reworked to give a more
+   consistent output across submodule boundary (and do its thing
+   without having to fork a separate process).
+
+ * A helper function to read a single whole line into strbuf
+   mistakenly triggered OOM error at EOF under certain conditions,
+   which has been fixed.
+
+ * The "ref-store" code reorganization continues.
+
+ * "git commit" used to discard the index and re-read from the filesystem
+   just in case the pre-commit hook has updated it in the middle; this
+   has been optimized out when we know we do not run the pre-commit hook.
+   (merge 680ee550d7 kw/commit-keep-index-when-pre-commit-is-not-run later to maint).
+
+ * Updates to the HTTP layer we made recently unconditionally used
+   features of libCurl without checking the existence of them, causing
+   compilation errors, which has been fixed.  Also migrate the code to
+   check feature macros, not version numbers, to cope better with
+   libCurl that vendor ships with backported features.
+
+ * The API to start showing progress meter after a short delay has
+   been simplified.
+   (merge 8aade107dd jc/simplify-progress later to maint).
+
+ * Code clean-up to avoid mixing values read from the .gitmodules file
+   and values read from the .git/config file.
+
+ * We used to spend more than necessary cycles allocating and freeing
+   piece of memory while writing each index entry out.  This has been
+   optimized.
+
+ * Platforms that ship with a separate sha1 with collision detection
+   library can link to it instead of using the copy we ship as part of
+   our source tree.
+
+ * Code around "notes" have been cleaned up.
+   (merge 3964281524 mh/notes-cleanup later to maint).
+
+ * The long-standing rule that an in-core lockfile instance, once it
+   is used, must not be freed, has been lifted and the lockfile and
+   tempfile APIs have been updated to reduce the chance of programming
+   errors.
+
+ * Our hashmap implementation in hashmap.[ch] is not thread-safe when
+   adding a new item needs to expand the hashtable by rehashing; add
+   an API to disable the automatic rehashing to work it around.
+
+ * Many of our programs consider that it is OK to release dynamic
+   storage that is used throughout the life of the program by simply
+   exiting, but this makes it harder to leak detection tools to avoid
+   reporting false positives.  Plug many existing leaks and introduce
+   a mechanism for developers to mark that the region of memory
+   pointed by a pointer is not lost/leaking to help these tools.
+
+ * As "git commit" to conclude a conflicted "git merge" honors the
+   commit-msg hook, "git merge" that records a merge commit that
+   cleanly auto-merges should, but it didn't.
+
+ * The codepath for "git merge-recursive" has been cleaned up.
+
+ * Many leaks of strbuf have been fixed.
+
+ * "git imap-send" has our own implementation of the protocol and also
+   can use more recent libCurl with the imap protocol support.  Update
+   the latter so that it can use the credential subsystem, and then
+   make it the default option to use, so that we can eventually
+   deprecate and remove the former.
+
+ * "make style" runs git-clang-format to help developers by pointing
+   out coding style issues.
+
+ * A test to demonstrate "git mv" failing to adjust nested submodules
+   has been added.
+   (merge c514167df2 hv/mv-nested-submodules-test later to maint).
+
+ * On Cygwin, "ulimit -s" does not report failure but it does not work
+   at all, which causes an unexpected success of some tests that
+   expect failures under a limited stack situation.  This has been
+   fixed.
+
+ * Many codepaths have been updated to squelch -Wimplicit-fallthrough
+   warnings from Gcc 7 (which is a good code hygiene).
+
+ * Add a helper for DLL loading in anticipation for its need in a
+   future topic RSN.
+
+ * "git status --ignored", when noticing that a directory without any
+   tracked path is ignored, still enumerated all the ignored paths in
+   the directory, which is unnecessary.  The codepath has been
+   optimized to avoid this overhead.
+
+ * The final batch to "git rebase -i" updates to move more code from
+   the shell script to C has been merged.
+
+ * Operations that do not touch (majority of) packed refs have been
+   optimized by making accesses to packed-refs file lazy; we no longer
+   pre-parse everything, and an access to a single ref in the
+   packed-refs does not touch majority of irrelevant refs, either.
+
+ * Add comment to clarify that the style file is meant to be used with
+   clang-5 and the rules are still work in progress.
+
+ * Many variables that points at a region of memory that will live
+   throughout the life of the program have been marked with UNLEAK
+   marker to help the leak checkers concentrate on real leaks..
+
+ * Plans for weaning us off of SHA-1 has been documented.
+
+ * A new "oidmap" API has been introduced and oidset API has been
+   rewritten to use it.
+
+
+Also contains various documentation updates and code clean-ups.
+
+
+Fixes since v2.14
+-----------------
+
+ * "%C(color name)" in the pretty print format always produced ANSI
+   color escape codes, which was an early design mistake.  They now
+   honor the configuration (e.g. "color.ui = never") and also tty-ness
+   of the output medium.
+
+ * The http.{sslkey,sslCert} configuration variables are to be
+   interpreted as a pathname that honors "~[username]/" prefix, but
+   weren't, which has been fixed.
+
+ * Numerous bugs in walking of reflogs via "log -g" and friends have
+   been fixed.
+
+ * "git commit" when seeing an totally empty message said "you did not
+   edit the message", which is clearly wrong.  The message has been
+   corrected.
+
+ * When a directory is not readable, "gitweb" fails to build the
+   project list.  Work this around by skipping such a directory.
+
+ * Some versions of GnuPG fails to kill gpg-agent it auto-spawned
+   and such a left-over agent can interfere with a test.  Work it
+   around by attempting to kill one before starting a new test.
+
+ * A recently added test for the "credential-cache" helper revealed
+   that EOF detection done around the time the connection to the cache
+   daemon is torn down were flaky.  This was fixed by reacting to
+   ECONNRESET and behaving as if we got an EOF.
+
+ * "git log --tag=no-such-tag" showed log starting from HEAD, which
+   has been fixed---it now shows nothing.
+
+ * The "tag.pager" configuration variable was useless for those who
+   actually create tag objects, as it interfered with the use of an
+   editor.  A new mechanism has been introduced for commands to enable
+   pager depending on what operation is being carried out to fix this,
+   and then "git tag -l" is made to run pager by default.
+
+ * "git push --recurse-submodules $there HEAD:$target" was not
+   propagated down to the submodules, but now it is.
+
+ * Commands like "git rebase" accepted the --rerere-autoupdate option
+   from the command line, but did not always use it.  This has been
+   fixed.
+
+ * "git clone --recurse-submodules --quiet" did not pass the quiet
+   option down to submodules.
+
+ * Test portability fix for OBSD.
+
+ * Portability fix for OBSD.
+
+ * "git am -s" has been taught that some input may end with a trailer
+   block that is not Signed-off-by: and it should refrain from adding
+   an extra blank line before adding a new sign-off in such a case.
+
+ * "git svn" used with "--localtime" option did not compute the tz
+   offset for the timestamp in question and instead always used the
+   current time, which has been corrected.
+
+ * Memory leak in an error codepath has been plugged.
+
+ * "git stash -u" used the contents of the committed version of the
+   ".gitignore" file to decide which paths are ignored, even when the
+   file has local changes.  The command has been taught to instead use
+   the locally modified contents.
+
+ * bash 4.4 or newer gave a warning on NUL byte in command
+   substitution done in "git stash"; this has been squelched.
+
+ * "git grep -L" and "git grep --quiet -L" reported different exit
+   codes; this has been corrected.
+
+ * When handshake with a subprocess filter notices that the process
+   asked for an unknown capability, Git did not report what program
+   the offending subprocess was running.  This has been corrected.
+
+ * "git apply" that is used as a better "patch -p1" failed to apply a
+   taken from a file with CRLF line endings to a file with CRLF line
+   endings.  The root cause was because it misused convert_to_git()
+   that tried to do "safe-crlf" processing by looking at the index
+   entry at the same path, which is a nonsense---in that mode, "apply"
+   is not working on the data in (or derived from) the index at all.
+   This has been fixed.
+
+ * Killing "git merge --edit" before the editor returns control left
+   the repository in a state with MERGE_MSG but without MERGE_HEAD,
+   which incorrectly tells the subsequent "git commit" that there was
+   a squash merge in progress.  This has been fixed.
+
+ * "git archive" did not work well with pathspecs and the
+   export-ignore attribute.
+
+ * In addition to "cc: <a@dd.re.ss> # cruft", "cc: a@dd.re.ss # cruft"
+   was taught to "git send-email" as a valid way to tell it that it
+   needs to also send a carbon copy to <a@dd.re.ss> in the trailer
+   section.
+
+ * "git branch -M a b" while on a branch that is completely unrelated
+   to either branch a or branch b misbehaved when multiple worktree
+   was in use.  This has been fixed.
+   (merge 31824d180d nd/worktree-kill-parse-ref later to maint).
+
+ * "git gc" and friends when multiple worktrees are used off of a
+   single repository did not consider the index and per-worktree refs
+   of other worktrees as the root for reachability traversal, making
+   objects that are in use only in other worktrees to be subject to
+   garbage collection.
+
+ * A regression to "gitk --bisect" by a recent update has been fixed.
+
+ * "git -c submodule.recurse=yes pull" did not work as if the
+   "--recurse-submodules" option was given from the command line.
+   This has been corrected.
+
+ * Unlike "git commit-tree < file", "git commit-tree -F file" did not
+   pass the contents of the file verbatim and instead completed an
+   incomplete line at the end, if exists.  The latter has been updated
+   to match the behaviour of the former.
+
+ * Many codepaths did not diagnose write failures correctly when disks
+   go full, due to their misuse of write_in_full() helper function,
+   which have been corrected.
+   (merge f48ecd38cb jk/write-in-full-fix later to maint).
+
+ * "git help co" now says "co is aliased to ...", not "git co is".
+   (merge b3a8076e0d ks/help-alias-label later to maint).
+
+ * "git archive", especially when used with pathspec, stored an empty
+   directory in its output, even though Git itself never does so.
+   This has been fixed.
+
+ * API error-proofing which happens to also squelch warnings from GCC.
+
+ * The explanation of the cut-line in the commit log editor has been
+   slightly tweaked.
+   (merge 8c4b1a3593 ks/commit-do-not-touch-cut-line later to maint).
+
+ * "git gc" tries to avoid running two instances at the same time by
+   reading and writing pid/host from and to a lock file; it used to
+   use an incorrect fscanf() format when reading, which has been
+   corrected.
+
+ * The scripts to drive TravisCI has been reorganized and then an
+   optimization to avoid spending cycles on a branch whose tip is
+   tagged has been implemented.
+   (merge 8376eb4a8f ls/travis-scriptify later to maint).
+
+ * The test linter has been taught that we do not like "echo -e".
+
+ * Code cmp.std.c nitpick.
+
+ * A regression fix for 2.11 that made the code to read the list of
+   alternate object stores overrun the end of the string.
+   (merge f0f7bebef7 jk/info-alternates-fix later to maint).
+
+ * "git describe --match" learned to take multiple patterns in v2.13
+   series, but the feature ignored the patterns after the first one
+   and did not work at all.  This has been fixed.
+
+ * "git filter-branch" cannot reproduce a history with a tag without
+   the tagger field, which only ancient versions of Git allowed to be
+   created.  This has been corrected.
+   (merge b2c1ca6b4b ic/fix-filter-branch-to-handle-tag-without-tagger later to maint).
+
+ * "git cat-file --textconv" started segfaulting recently, which
+   has been corrected.
+
+ * The built-in pattern to detect the "function header" for HTML did
+   not match <H1>..<H6> elements without any attributes, which has
+   been fixed.
+
+ * "git mailinfo" was loose in decoding quoted printable and produced
+   garbage when the two letters after the equal sign are not
+   hexadecimal.  This has been fixed.
+
+ * The machinery to create xdelta used in pack files received the
+   sizes of the data in size_t, but lost the higher bits of them by
+   storing them in "unsigned int" during the computation, which is
+   fixed.
+
+ * The delta format used in the packfile cannot reference data at
+   offset larger than what can be expressed in 4-byte, but the
+   generator for the data failed to make sure the offset does not
+   overflow.  This has been corrected.
+
+ * The documentation for '-X<option>' for merges was misleadingly
+   written to suggest that "-s theirs" exists, which is not the case.
+
+ * "git fast-export" with -M/-C option issued "copy" instruction on a
+   path that is simultaneously modified, which was incorrect.
+   (merge b3e8ca89cf jt/fast-export-copy-modify-fix later to maint).
+
+ * Many codepaths have been updated to squelch -Wsign-compare
+   warnings.
+   (merge 071bcaab64 rj/no-sign-compare later to maint).
+
+ * Memory leaks in various codepaths have been plugged.
+   (merge 4d01a7fa65 ma/leakplugs later to maint).
+
+ * Recent versions of "git rev-parse --parseopt" did not parse the
+   option specification that does not have the optional flags (*=?!)
+   correctly, which has been corrected.
+   (merge a6304fa4c2 bc/rev-parse-parseopt-fix later to maint).
+
+ * The checkpoint command "git fast-import" did not flush updates to
+   refs and marks unless at least one object was created since the
+   last checkpoint, which has been corrected, as these things can
+   happen without any new object getting created.
+   (merge 30e215a65c er/fast-import-dump-refs-on-checkpoint later to maint).
+
+ * Spell the name of our system as "Git" in the output from
+   request-pull script.
+
+ * Fixes for a handful memory access issues identified by valgrind.
+
+ * Backports a moral equivalent of 2015 fix to the poll() emulation
+   from the upstream gnulib to fix occasional breakages on HPE NonStop.
+
+ * Users with "color.ui = always" in their configuration were broken
+   by a recent change that made plumbing commands to pay attention to
+   them as the patch created internally by "git add -p" were colored
+   (heh) and made unusable.  This has been fixed by reverting the
+   offending change.
+
+ * In the "--format=..." option of the "git for-each-ref" command (and
+   its friends, i.e. the listing mode of "git branch/tag"), "%(atom:)"
+   (e.g. "%(refname:)", "%(body:)" used to error out.  Instead, treat
+   them as if the colon and an empty string that follows it were not
+   there.
+
+ * An ancient bug that made Git misbehave with creation/renaming of
+   refs has been fixed.
+
+ * "git fetch <there> <src>:<dst>" allows an object name on the <src>
+   side when the other side accepts such a request since Git v2.5, but
+   the documentation was left stale.
+   (merge 83558a412a jc/fetch-refspec-doc-update later to maint).
+
+ * Update the documentation for "git filter-branch" so that the filter
+   options are listed in the same order as they are applied, as
+   described in an earlier part of the doc.
+   (merge 07c4984508 dg/filter-branch-filter-order-doc later to maint).
+
+ * A possible oom error is now caught as a fatal error, instead of
+   continuing and dereferencing NULL.
+   (merge 55d7d15847 ao/path-use-xmalloc later to maint).
+
+ * Other minor doc, test and build updates and code cleanups.
+   (merge f094b89a4d ma/parse-maybe-bool later to maint).
+   (merge 6cdf8a7929 ma/ts-cleanups later to maint).
+   (merge 7560f547e6 ma/up-to-date later to maint).
+   (merge 0db3dc75f3 rs/apply-epoch later to maint).
+   (merge 276d0e35c0 ma/split-symref-update-fix later to maint).
+   (merge f777623514 ks/branch-tweak-error-message-for-extra-args later to maint).
+   (merge 33f3c683ec ks/verify-filename-non-option-error-message-tweak later to maint).
+   (merge 7cbbf9d6a2 ls/filter-process-delayed later to maint).
+   (merge 488aa65c8f wk/merge-options-gpg-sign-doc later to maint).
+   (merge e61cb19a27 jc/branch-force-doc-readability-fix later to maint).
+   (merge 32fceba3fd np/config-path-doc later to maint).
+   (merge e38c681fb7 sb/rev-parse-show-superproject-root later to maint).
+   (merge 4f851dc883 sg/rev-list-doc-reorder-fix later to maint).