Git v2.52 Release Notes
=======================

UI, Workflows & Features
------------------------

 * The "list" subcommand of "git refs" acts as a front-end for
   "git for-each-ref".

 * "git cmd --help-all" now works outside repositories.

 * "git diff-tree" learned "--max-depth" option.

 * A new subcommand "git repo" gives users a way to grab various
   repository characteristics.

 * A new command "git last-modified" has been added to show the closest
   ancestor commit that touched each path.

 * "git refs exists" that works like "git show-ref --exists" has been
   added.

 * "repo info" learns a short-hand option "-z" that is the same as
   "--format=nul", and learns to report the objects format used in the
   repository.

 * "core.commentChar=auto" that attempts to dynamically pick a
   suitable comment character is non-workable, as it is too much
   trouble to support for little benefit, and is marked as deprecated.

 * "git send-email" learned to drive "git imap-send" to store already
   sent e-mails in an IMAP folder.

 * The "promisor-remote" capability mechanism has been updated to
   allow the "partialCloneFilter" settings and the "token" value to be
   communicated from the server side.

 * Declare that "git init" that is not otherwise configured uses
   'main' as the initial branch, not 'master', starting Git 3.0.

 * Keep giving hint about the default initial branch name for users
   who may be surprised after Git 3.0 switch-over.

 * The stash.index configuration variable can be set to make "git stash
   pop/apply" pretend that it was invoked with "--index".

 * "git fast-import" learned that "--signed-commits=<how>" option that
   corresponds to that of "git fast-export".

 * Marking a hunk 'selected' in "git add -p" and then splitting made
   all the split pieces 'selected'; this has been changed to make them
   all 'undecided', which gives better end-user experience.

 * Configuration variables that take a pathname as a value
   (e.g. blame.ignorerevsfile) can be marked as optional by prefixing
   ":(optoinal)" before its value.

 * Show 'P'ipe command in "git add -p".

 * "git sparse-checkout" subcommand learned a new "clean" action to
   prune otherwise unused working-tree files that are outside the
   areas of interest.

 * "git fast-import" is taught to handle signed tags, just like it
   recently learned to handle signed commits, in different ways.

 * A new configuration variable commitGraph.changedPaths allows to
   turn "--changed-paths" on by default for "git commit-graph".

 * "Symlink symref" has been added to the list of things that will
   disappear at Git 3.0 boundary.

 * "git maintenance" command learns the "geometric" strategy where it
   avoids doing maintenance tasks that rebuilds everything from
   scratch.


Performance, Internal Implementation, Development Support etc.
--------------------------------------------------------------

 * string_list_split*() family of functions have been extended to
   simplify common use cases.

 * Arrays of strbuf is often a wrong data structure to use, and
   strbuf_split*() family of functions that create them often have
   better alternatives.  Update several code paths and replace
   strbuf_split*().

 * Revision traversal limited with pathspec, like "git log dir/*",
   used to ignore changed-paths Bloom filter when the pathspec
   contained wildcards; now they take advantage of the filter when
   they can.

 * Doc lint updates to encourage the newer and easier-to-use
   `synopsis` format, with fixes to a handful of existing uses.

 * Remove dependency on the_repository and other globals from the
   commit-graph code, and other changes unrelated to de-globaling.

 * Discord has been added to the first contribution documentation as
   another way to ask for help.

 * Inspired by Ezekiel's recent effort to showcase Rust interface, the
   hash function implementation used to hash lines have been updated
   to the one used for ELF symbol lookup by Glibc.

 * Instead of scanning for the remaining items to see if there are
   still commits to be explored in the queue, use khash to remember
   which items are still on the queue (an unacceptable alternative is
   to reserve one object flag bits).

 * The bulk-checkin code used to depend on a file-scope static
   singleton variable, which has been updated to pass an instance
   throughout the callchain.

 * The work to build on the bulk-checkin infrastructure to create many
   objects at once in a transaction and to abstract it into the
   generic object layer continues.

 * CodingGuidelines now spells out how bitfields are to be written.

 * Adjust to the way newer versions of cURL selectively enable tracing
   options, so that our tests can continue to work.

 * The clear_alloc_state() API function was not fully clearing the
   structure for reuse, but since nobody reuses it, replace it with a
   variant that frees the structure as well, making the callers simpler.

 * "git range-diff" learned a way to limit the memory consumed by
   O(N*N) cost matrix.

 * Some places in the code confused a variable that is *not* a boolean
   to enable color but is an enum that records what the user requested
   to do about color.  A couple of bugs of this sort have been fixed,
   while the code has been cleaned up to prevent similar bugs in the
   future.

 * The build procedure based on meson learned a target to only build
   documentation, similar to "make doc".
   (merge ff4ec8ded0 ps/meson-build-docs later to maint).

 * Dip our toes a bit to (optionally) use Rust implemented helper
   called from our C code.

 * Documentation for "git log --pretty" options has been updated
   to make it easier to translate.

 * Instead of three library archives (one for git, one for reftable,
   and one for xdiff), roll everything into a single libgit.a archive.
   This would help later effort to FFI into Rust.

 * The beginning of SHA1-SHA256 interoperability work.

 * Build procedure for a few credential helpers (in contrib/) have
   been updated.

 * CI improvements to handle the recent Rust integration better.

 * The code in "git repack" machinery has been cleaned up to prepare
   for incremental update of midx files.

 * Two slightly different ways to get at "all the packfiles" in API
   has been cleaned up.

 * The code to walk revision graph to compute merge base has been
   optimized.


Fixes since v2.51
-----------------

Unless otherwise noted, all the changes in 2.51.X maintenance track,
including security updates, are included in this release.

 * During interactive rebase, using 'drop' on a merge commit lead to
   an error, which was incorrect.

 * "git refs migrate" to migrate the reflog entries from a refs
   backend to another had a handful of bugs squashed.

 * "git remote rename origin upstream" failed to move origin/HEAD to
   upstream/HEAD when origin/HEAD is unborn and performed other
   renames extremely inefficiently, which has been corrected.
   (merge 16c4fa26b9 ps/remote-rename-fix later to maint).

 * "git describe" has been optimized by using better data structure.
   (merge 08bb69d70f rs/describe-with-prio-queue later to maint).

 * "git push" had a code path that led to BUG() but it should have
   been a die(), as it is a response to a usual but invalid end-user
   action to attempt pushing an object that does not exist.

 * Various bugs about rename handling in "ort" merge strategy have
   been fixed.

 * "git jump" (in contrib/) fails to parse the diff header correctly
   when a file has a space in its name, which has been corrected.
   (merge 621ce9c1c6 gh/git-jump-pathname-with-sp later to maint).

 * "git diff --no-index" run inside a subdirectory under control of a
   Git repository operated at the top of the working tree and stripped
   the prefix from the output, and oddballs like "-" (stdin) did not
   work correctly because of it.  Correct the set-up by undoing what
   the set-up sequence did to cwd and prefix.

 * Various options to "git diff" that makes comparison ignore certain
   aspects of the differences (like "space changes are ignored",
   "differences in lines that match these regular expressions are
   ignored") did not work well with "--name-only" and friends.
   (merge b55e6d36eb ly/diff-name-only-with-diff-from-content later to maint).

 * The above caused regressions, which has been corrected.

 * Documentation for "git rebase" has been updated.
   (merge 3f7f2b0359 je/doc-rebase later to maint).

 * The start_delayed_progress() function in the progress eye-candy API
   did not clear its internal state, making an initial delay value
   larger than 1 second ineffective, which has been corrected.

 * The compatObjectFormat extension is used to hide an incomplete
   feature that is not yet usable for any purpose other than
   developing the feature further.  Document it as such to discourage
   its use by mere mortals.

 * "git log -L..." compared trees of multiple parents with the tree of the
   merge result in an unnecessarily inefficient way.
   (merge 0a15bb634c sg/line-log-merge-optim later to maint).

 * Under a race against another process that is repacking the
   repository, especially a partially cloned one, "git fetch" may
   mistakenly think some objects we do have are missing, which has
   been corrected.

 * "git fetch" can clobber a symref that is dangling when the
   remote-tracking HEAD is set to auto update, which has been
   corrected.

 * "git describe <blob>" misbehaves and/or crashes in some corner
   cases, which has been taught to exit with failure gracefully.
   (merge 7c10e48e81 jk/describe-blob later to maint).

 * Manual page for "gitk" is updated with the current maintainer's
   name.

 * Update the instructions for using GGG in the MyFirstContribution
   document to say that a GitHub PR could be made against `git/git`
   instead of `gitgitgadget/git`.

 * Makefile tried to run multiple "cargo build" which would not work
   very well; serialize their execution to work around this problem.

 * "git repack --path-walk" lost objects in some corner cases, which
   has been corrected.

 * "git ls-files <pathspec>..." should not necessarily have to expand
   the index fully if a sparsified directory is excluded by the
   pathspec; the code is taught to expand the index on demand to avoid
   this.
   (merge 681f26bccc ds/ls-files-lazy-unsparse later to maint).

 * Windows "real-time monitoring" interferes with the execution of
   tests and affects negatively in both correctness and performance,
   which has been disabled in Gitlab CI.

 * A broken or malicious "git fetch" can say that it has the same
   object for many many times, and the upload-pack serving it can
   exhaust memory storing them redundantly, which has been corrected.

 * A corner case bug in "git log -L..." has been corrected.

 * "git rev-parse --short" and friends failed to disambiguate two
   objects with object names that share common prefix longer than 32
   characters, which has been fixed.
   (merge 8655908b9e jc/longer-disambiguation-fix later to maint).

 * Some among "git add -p" and friends ignored color.diff and/or
   color.ui configuration variables, which is an old regression, which
   has been corrected.

 * "git subtree" (in contrib/) did not work correctly when splitting
   squashed subtrees, which has been improved.

 * Import a newer version of the clar unit testing framework.
   (merge 93dbb6b3c5 ps/clar-updates later to maint).

 * "git send-email --compose --reply-to=<address>" used to add
   duplicated Reply-To: header, which made mailservers unhappy.  This
   has been corrected.
   (merge f448f65719 nb/send-email-no-dup-reply-to later to maint).

 * "git rebase -i" failed to clean-up the commit log message when the
   command commits the final one in a chain of "fixup" commands, which
   has been corrected.

 * There are double frees and leaks around setup_revisions() API used
   in "git stash show", which has been fixed, and setup_revisions()
   API gained a wrapper to make it more ergonomic when using it with
   strvec-manged argc/argv pairs.
   (merge a04bc71725 jk/setup-revisions-freefix later to maint).

 * Deal more gracefully with directory / file conflicts when the files
   backend is used for ref storage, by failing only the ones that are
   involved in the conflict while allowing others.

 * "git last-modified" operating in non-recursive mode used to trigger
   a BUG(), which has been corrected.

 * The use of "git config get" command to learn how ANSI color
   sequence is for a particular type, e.g., "git config get
   --type=color --default=reset no.such.thing", isn't very ergonomic.
   (merge e4dabf4fd6 ps/config-get-color-fixes later to maint).

 * The "do you still use it?" message given by a command that is
   deeply deprecated and allow us to suggest alternatives has been
   updated.

 * Clang-format update to let our control macros be formatted the way we
   had them traditionally, e.g., "for_each_string_list_item()" without
   space before the parentheses.

 * A few places where a size_t value was cast to curl_off_t without
   checking has been updated to use the existing helper function.

 * "git reflog write" did not honor the configured user.name/email
   which has been corrected.

 * Handling of an empty subdirectory of .git/refs/ in the ref-files
   backend has been corrected.

 * Our CI script requires "sudo" that can be told to preserve
   environment, but Ubuntu replaced with "sudo" with an implementation
   that lacks the feature.  Work this around by reinstalling the
   original version.

 * The reftable backend learned to sanity check its on-disk data more
   carefully.
   (merge 466a3a1afd kn/reftable-consistency-checks later to maint).

 * A lot of code clean-up of xdiff.
   Split out of a larger topic.
   (merge 8b9c5d2e3a en/xdiff-cleanup later to maint).

 * "git format-patch --range-diff=... --notes=..." did not drive the
   underlying range-diff with correct --notes parameter, ending up
   comparing with different set of notes from its main patch output
   you would get from "git format-patch --notes=..." for a singleton
   patch.

 * The code in "git add -p" and friends to iterate over hunks was
   riddled with bugs, which has been corrected.

 * A few more things that patch authors can do to help maintainer to
   keep track of their topics better.
   (merge 1a41698841 tb/doc-submitting-patches later to maint).

 * An earlier addition to "git diff --no-index A B" to limit the
   output with pathspec after the two directories misbehaved when
   these directories were given with a trailing slash, which has been
   corrected.

 * The "--short" option of "git status" that meant output for humans
   and "-z" option to show NUL delimited output format did not mix
   well, and colored some but not all things.  The command has been
   updated to color all elements consistently in such a case.

 * Unicode width table update.

 * GPG signing test set-up has been broken for a year, which has been
   corrected.
   (merge 516bf45749 jc/t1016-setup-fix later to maint).

 * Recent OpenSSH creates the Unix domain socket to communicate with
   ssh-agent under $HOME instead of /tmp, which causes our test to
   fail doe to overly long pathname in our test environment, which has
   been worked around by using "ssh-agent -T".

 * strbuf_split*() to split a string into multiple strbufs is often a
   wrong API to use.  A few uses of it have been removed by
   simplifying the code.
   (merge 2ab72a16d9 ob/gpg-interface-cleanup later to maint).

 * "git shortlog" knows "--committer" and "--author" options, which
   the command line completion (in contrib/) did not handle well,
   which has been corrected.
   (merge c568fa8e1c kf/log-shortlog-completion-fix later to maint).

 * "git bisect" command did not react correctly to "git bisect help"
   and "git bisect unknown", which has been corrected.
   (merge 2bb3a012f3 rz/bisect-help-unknown later to maint).

 * The 'q'(uit) command in "git add -p" has been improved to quit
   without doing any meaningless work before leaving, and giving EOF
   (typically control-D) to the prompt is made to behave the same way.

 * The wildmatch code had a corner case bug that mistakenly makes
   "foo**/bar" match with "foobar", which has been corrected.
   (merge 1940a02dc1 jk/match-pathname-fix later to maint).

 * Other code cleanup, docfix, build fix, etc.
   (merge 529a60a885 ua/t1517-short-help-tests later to maint).
   (merge 22d421fed9 ac/deglobal-fmt-merge-log-config later to maint).
   (merge a60203a015 dk/t7005-editor-updates later to maint).
   (merge 16684b6fae ps/reftable-libgit2-cleanup later to maint).
   (merge e5c27bd3d8 je/doc-add later to maint).
   (merge 13296ac909 ps/object-store-midx-dedup-info later to maint).
   (merge f9a6705d9a tc/t0450-harden later to maint).
   (merge a66fc22bf9 rs/get-oid-with-flags-cleanup later to maint).
   (merge 15b8abde07 js/mingw-includes-cleanup later to maint).
   (merge 2cebca0582 tb/cat-file-objectmode-update later to maint).
   (merge 8f487db07a kh/doc-patch-id-1 later to maint).
