RelNotes/2.12.0.adoc

Git 2.12 Release Notes
======================

Backward compatibility notes.

 * Use of an empty string 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 not scheduled to happen in the upcoming release (yet).

 * The historical argument order "git merge <msg> HEAD <commit>..."
   has been deprecated for quite some time, and will be removed in a
   future release.

 * An ancient script "git relink" has been removed.


Updates since v2.11
-------------------

UI, Workflows & Features

 * Various updates to "git p4".

 * "git p4" didn't interact with the internal of .git directory
   correctly in the modern "git-worktree"-enabled world.

 * "git branch --list" and friends learned "--ignore-case" option to
   optionally sort branches and tags case insensitively.

 * In addition to %(subject), %(body), "log --pretty=format:..."
   learned a new placeholder %(trailers).

 * "git rebase" learned "--quit" option, which allows a user to
   remove the metadata left by an earlier "git rebase" that was
   manually aborted without using "git rebase --abort".

 * "git clone --reference $there --recurse-submodules $super" has been
   taught to guess repositories usable as references for submodules of
   $super that are embedded in $there while making a clone of the
   superproject borrow objects from $there; extend the mechanism to
   also allow submodules of these submodules to borrow repositories
   embedded in these clones of the submodules embedded in the clone of
   the superproject.

 * Porcelain scripts written in Perl are getting internationalized.

 * "git merge --continue" has been added as a synonym to "git commit"
   to conclude a merge that has stopped due to conflicts.

 * Finer-grained control of what protocols are allowed for transports
   during clone/fetch/push have been enabled via a new configuration
   mechanism.

 * "git shortlog" learned "--committer" option to group commits by
   committer, instead of author.

 * GitLFS integration with "git p4" has been updated.

 * The isatty() emulation for Windows has been updated to eradicate
   the previous hack that depended on internals of (older) MSVC
   runtime.

 * Some platforms no longer understand "latin-1" that is still seen in
   the wild in e-mail headers; replace them with "iso-8859-1" that is
   more widely known when conversion fails from/to it.

 * "git grep" has been taught to optionally recurse into submodules.

 * "git rm" used to refuse to remove a submodule when it has its own
   git repository embedded in its working tree.  It learned to move
   the repository away to $GIT_DIR/modules/ of the superproject
   instead, and allow the submodule to be deleted (as long as there
   will be no loss of local modifications, that is).

 * A recent updates to "git p4" was not usable for older p4 but it
   could be made to work with minimum changes.  Do so.

 * "git diff" learned diff.interHunkContext configuration variable
   that gives the default value for its --inter-hunk-context option.

 * The prereleaseSuffix feature of version comparison that is used in
   "git tag -l" did not correctly when two or more prereleases for the
   same release were present (e.g. when 2.0, 2.0-beta1, and 2.0-beta2
   are there and the code needs to compare 2.0-beta1 and 2.0-beta2).

 * "git submodule push" learned "--recurse-submodules=only option to
   push submodules out without pushing the top-level superproject.

 * "git tag" and "git verify-tag" learned to put GPG verification
   status in their "--format=<placeholders>" output format.

 * An ancient repository conversion tool left in contrib/ has been
   removed.

 * "git show-ref HEAD" used with "--verify" because the user is not
   interested in seeing refs/remotes/origin/HEAD, and used with
   "--head" because the user does not want HEAD to be filtered out,
   i.e. "git show-ref --head --verify HEAD", did not work as expected.

 * "git submodule add" used to be confused and refused to add a
   locally created repository; users can now use "--force" option
   to add them.
   (merge 619acfc78c sb/submodule-add-force later to maint).

 * Some people feel the default set of colors used by "git log --graph"
   rather limiting.  A mechanism to customize the set of colors has
   been introduced.

 * "git read-tree" and its underlying unpack_trees() machinery learned
   to report problematic paths prefixed with the --super-prefix option.

 * When a submodule "A", which has another submodule "B" nested within
   it, is "absorbed" into the top-level superproject, the inner
   submodule "B" used to be left in a strange state.  The logic to
   adjust the .git pointers in these submodules has been corrected.

 * The user can specify a custom update method that is run when
   "submodule update" updates an already checked out submodule.  This
   was ignored when checking the submodule out for the first time and
   we instead always just checked out the commit that is bound to the
   path in the superproject's index.

 * The command line completion (in contrib/) learned that
   "git diff --submodule=" can take "diff" as a recently added option.

 * The "core.logAllRefUpdates" that used to be boolean has been
   enhanced to take 'always' as well, to record ref updates to refs
   other than the ones that are expected to be updated (i.e. branches,
   remote-tracking branches and notes).

 * Comes with more command line completion (in contrib/) for recently
   introduced options.


Performance, Internal Implementation, Development Support etc.

 * Commands that operate on a log message and add lines to the trailer
   blocks, such as "format-patch -s", "cherry-pick (-x|-s)", and
   "commit -s", have been taught to use the logic of and share the
   code with "git interpret-trailer".

 * The default Travis-CI configuration specifies newer P4 and GitLFS.

 * The "fast hash" that had disastrous performance issues in some
   corner cases has been retired from the internal diff.

 * The character width table has been updated to match Unicode 9.0

 * Update the procedure to generate "tags" for developer support.

 * The codeflow of setting NOATIME and CLOEXEC on file descriptors Git
   opens has been simplified.

 * "git diff" and its family had two experimental heuristics to shift
   the contents of a hunk to make the patch easier to read.  One of
   them turns out to be better than the other, so leave only the
   "--indent-heuristic" option and remove the other one.

 * A new submodule helper "git submodule embedgitdirs" to make it
   easier to move embedded .git/ directory for submodules in a
   superproject to .git/modules/ (and point the latter with the former
   that is turned into a "gitdir:" file) has been added.

 * "git push \\server\share\dir" has recently regressed and then
   fixed.  A test has retroactively been added for this breakage.

 * Build updates for Cygwin.

 * The implementation of "real_path()" was to go there with chdir(2)
   and call getcwd(3), but this obviously wouldn't be usable in a
   threaded environment.  Rewrite it to manually resolve relative
   paths including symbolic links in path components.

 * Adjust documentation to help AsciiDoctor render better while not
   breaking the rendering done by AsciiDoc.

 * The sequencer machinery has been further enhanced so that a later
   set of patches can start using it to reimplement "rebase -i".

 * Update the definition of the MacOSX test environment used by
   TravisCI.

 * Rewrite a scripted porcelain "git difftool" in C.

 * "make -C t failed" will now run only the tests that failed in the
   previous run.  This is usable only when prove is not use, and gives
   a useless error message when run after "make clean", but otherwise
   is serviceable.

 * "uchar [40]" to "struct object_id" conversion continues.


Also contains various documentation updates and code clean-ups.

Fixes since v2.10
-----------------

Unless otherwise noted, all the fixes since v2.9 in the maintenance
track are contained in this release (see the maintenance releases'
notes for details).

 * We often decide if a session is interactive by checking if the
   standard I/O streams are connected to a TTY, but isatty() that
   comes with Windows incorrectly returned true if it is used on NUL
   (i.e. an equivalent to /dev/null).  This has been fixed.

 * "git svn" did not work well with path components that are "0", and
   some configuration variable it uses were not documented.

 * "git rev-parse --symbolic" failed with a more recent notation like
   "HEAD^-1" and "HEAD^!".

 * An empty directory in a working tree that can simply be nuked used
   to interfere while merging or cherry-picking a change to create a
   submodule directory there, which has been fixed..

 * The code in "git push" to compute if any commit being pushed in the
   superproject binds a commit in a submodule that hasn't been pushed
   out was overly inefficient, making it unusable even for a small
   project that does not have any submodule but have a reasonable
   number of refs.

 * "git push --dry-run --recurse-submodule=on-demand" wasn't
   "--dry-run" in the submodules.

 * The output from "git worktree list" was made in readdir() order,
   and was unstable.

 * mergetool.<tool>.trustExitCode configuration variable did not apply
   to built-in tools, but now it does.

 * "git p4" LFS support was broken when LFS stores an empty blob.

 * A corner case in merge-recursive regression that crept in
   during 2.10 development cycle has been fixed.

 * Transport with dumb http can be fooled into following foreign URLs
   that the end user does not intend to, especially with the server
   side redirects and http-alternates mechanism, which can lead to
   security issues.  Tighten the redirection and make it more obvious
   to the end user when it happens.

 * Update the error messages from the dumb-http client when it fails
   to obtain loose objects; we used to give sensible error message
   only upon 404 but we now forbid unexpected redirects that needs to
   be reported with something sensible.

 * When diff.renames configuration is on (and with Git 2.9 and later,
   it is enabled by default, which made it worse), "git stash"
   misbehaved if a file is removed and another file with a very
   similar content is added.

 * "git diff --no-index" did not take "--no-abbrev" option.

 * "git difftool --dir-diff" had a minor regression when started from
   a subdirectory, which has been fixed.

 * "git commit --allow-empty --only" (no pathspec) with dirty index
   ought to be an acceptable way to create a new commit that does not
   change any paths, but it was forbidden, perhaps because nobody
   needed it so far.

 * Git 2.11 had a minor regression in "merge --ff-only" that competed
   with another process that simultaneously attempted to update the
   index. We used to explain what went wrong with an error message,
   but the new code silently failed.  The error message has been
   resurrected.

 * A pathname that begins with "//" or "\\" on Windows is special but
   path normalization logic was unaware of it.

 * "git pull --rebase", when there is no new commits on our side since
   we forked from the upstream, should be able to fast-forward without
   invoking "git rebase", but it didn't.

 * The way to specify hotkeys to "xxdiff" that is used by "git
   mergetool" has been modernized to match recent versions of xxdiff.

 * Unlike "git am --abort", "git cherry-pick --abort" moved HEAD back
   to where cherry-pick started while picking multiple changes, when
   the cherry-pick stopped to ask for help from the user, and the user
   did "git reset --hard" to a different commit in order to re-attempt
   the operation.

 * Code cleanup in shallow boundary computation.

 * A recent update to receive-pack to make it easier to drop garbage
   objects made it clear that GIT_ALTERNATE_OBJECT_DIRECTORIES cannot
   have a pathname with a colon in it (no surprise!), and this in turn
   made it impossible to push into a repository at such a path.  This
   has been fixed by introducing a quoting mechanism used when
   appending such a path to the colon-separated list.

 * The function usage_msg_opt() has been updated to say "fatal:"
   before the custom message programs give, when they want to die
   with a message about wrong command line options followed by the
   standard usage string.

 * "git index-pack --stdin" needs an access to an existing repository,
   but "git index-pack file.pack" to generate an .idx file that
   corresponds to a packfile does not.

 * Fix for NDEBUG builds.

 * A lazy "git push" without refspec did not internally use a fully
   specified refspec to perform 'current', 'simple', or 'upstream'
   push, causing unnecessary "ambiguous ref" errors.

 * "git p4" misbehaved when swapping a directory and a symbolic link.

 * Even though an fix was attempted in Git 2.9.3 days, but running
   "git difftool --dir-diff" from a subdirectory never worked. This
   has been fixed.

 * "git p4" that tracks multiple p4 paths imported a single changelist
   that touches files in these multiple paths as one commit, followed
   by many empty commits.  This has been fixed.

 * A potential but unlikely buffer overflow in Windows port has been
   fixed.

 * When the http server gives an incomplete response to a smart-http
   rpc call, it could lead to client waiting for a full response that
   will never come.  Teach the client side to notice this condition
   and abort the transfer.

 * Compression setting for producing packfiles were spread across
   three codepaths, one of which did not honor any configuration.
   Unify these so that all of them honor core.compression and
   pack.compression variables the same way.

 * "git fast-import" sometimes mishandled while rebalancing notes
   tree, which has been fixed.

 * Recent update to the default abbreviation length that auto-scales
   lacked documentation update, which has been corrected.

 * Leakage of lockfiles in the config subsystem has been fixed.

 * It is natural that "git gc --auto" may not attempt to pack
   everything into a single pack, and there is no point in warning
   when the user has configured the system to use the pack bitmap,
   leading to disabling further "gc".

 * "git archive" did not read the standard configuration files, and
   failed to notice a file that is marked as binary via the userdiff
   driver configuration.

 * "git blame --porcelain" misidentified the "previous" <commit, path>
   pair (aka "source") when contents came from two or more files.

 * "git rebase -i" with a recent update started showing an incorrect
   count when squashing more than 10 commits.

 * "git <cmd> @{push}" on a detached HEAD used to segfault; it has
   been corrected to error out with a message.

 * Running "git add a/b" when "a" is a submodule correctly errored
   out, but without a meaningful error message.
   (merge 2d81c48fa7 sb/pathspec-errors later to maint).

 * Typing ^C to pager, which usually does not kill it, killed Git and
   took the pager down as a collateral damage in certain process-tree
   structure.  This has been fixed.

 * "git mergetool" without any pathspec on the command line that is
   run from a subdirectory became no-op in Git v2.11 by mistake, which
   has been fixed.

 * Retire long unused/unmaintained gitview from the contrib/ area.
   (merge 3120925c25 sb/remove-gitview later to maint).

 * Tighten a test to avoid mistaking an extended ERE regexp engine as
   a PRE regexp engine.

 * An error message with an ASCII control character like '\r' in it
   can alter the message to hide its early part, which is problematic
   when a remote side gives such an error message that the local side
   will relay with a "remote: " prefix.
   (merge f290089879 jk/vreport-sanitize later to maint).

 * "git fsck" inspects loose objects more carefully now.
   (merge cce044df7f jk/loose-object-fsck later to maint).

 * A crashing bug introduced in v2.11 timeframe has been found (it is
   triggerable only in fast-import) and fixed.
   (merge abd5a00268 jk/clear-delta-base-cache-fix later to maint).

 * With an anticipatory tweak for remotes defined in ~/.gitconfig
   (e.g. "remote.origin.prune" set to true, even though there may or
   may not actually be "origin" remote defined in a particular Git
   repository), "git remote rename" and other commands misinterpreted
   and behaved as if such a non-existing remote actually existed.
   (merge e459b073fb js/remote-rename-with-half-configured-remote later to maint).

 * A few codepaths had to rely on a global variable when sorting
   elements of an array because sort(3) API does not allow extra data
   to be passed to the comparison function.  Use qsort_s() when
   natively available, and a fallback implementation of it when not,
   to eliminate the need, which is a prerequisite for making the
   codepath reentrant.

 * "git fsck --connectivity-check" was not working at all.
   (merge a2b22854bd jk/fsck-connectivity-check-fix later to maint).

 * After starting "git rebase -i", which first opens the user's editor
   to edit the series of patches to apply, but before saving the
   contents of that file, "git status" failed to show the current
   state (i.e. you are in an interactive rebase session, but you have
   applied no steps yet) correctly.
   (merge df9ded4984 js/status-pre-rebase-i later to maint).

 * Test tweak for FreeBSD where /usr/bin/unzip is unsuitable to run
   our tests but /usr/local/bin/unzip is usable.
   (merge d98b2c5fce js/unzip-in-usr-bin-workaround later to maint).

 * "git p4" did not work well with multiple git-p4.mapUser entries on
   Windows.
   (merge c3c2b05776 gv/mingw-p4-mapuser later to maint).

 * "git help" enumerates executable files in $PATH; the implementation
   of "is this file executable?" on Windows has been optimized.
   (merge c755015f79 hv/mingw-help-is-executable later to maint).

 * Test tweaks for those who have default ACL in their git source tree
   that interfere with the umask test.
   (merge d549d21307 mm/reset-facl-before-umask-test later to maint).

 * Names of the various hook scripts must be spelled exactly, but on
   Windows, an .exe binary must be named with .exe suffix; notice
   $GIT_DIR/hooks/<hookname>.exe as a valid <hookname> hook.
   (merge 235be51fbe js/mingw-hooks-with-exe-suffix later to maint).

 * Asciidoctor, an alternative reimplementation of AsciiDoc, still
   needs some changes to work with documents meant to be formatted
   with AsciiDoc.  "make USE_ASCIIDOCTOR=YesPlease" to use it out of
   the box to document our pages is getting closer to reality.

 * Correct command line completion (in contrib/) on "git svn"
   (merge 2cbad17642 ew/complete-svn-authorship-options later to maint).

 * Incorrect usage help message for "git worktree prune" has been fixed.
   (merge 2488dcab22 ps/worktree-prune-help-fix later to maint).

 * Adjust a perf test to new world order where commands that do
   require a repository are really strict about having a repository.
   (merge c86000c1a7 rs/p5302-create-repositories-before-tests later to maint).

 * "git log --graph" did not work well with "--name-only", even though
   other forms of "diff" output were handled correctly.
   (merge f5022b5fed jk/log-graph-name-only later to maint).

 * The push-options given via the "--push-options" option were not
   passed through to external remote helpers such as "smart HTTP" that
   are invoked via the transport helper.

 * The documentation explained what "git stash" does to the working
   tree (after stashing away the local changes) in terms of "reset
   --hard", which was exposing an unnecessary implementation detail.
   (merge 20a7e06172 tg/stash-doc-cleanup later to maint).

 * When "git p4" imports changelist that removes paths, it failed to
   convert pathnames when the p4 used encoding different from the one
   used on the Git side.  This has been corrected.
   (merge a8b05162e8 ls/p4-path-encoding later to maint).

 * A new coccinelle rule that catches a check of !pointer before the
   pointer is free(3)d, which most likely is a bug.
   (merge ec6cd14c7a rs/cocci-check-free-only-null later to maint).

 * "ls-files" run with pathspec has been micro-optimized to avoid
   having to memmove(3) unnecessary bytes.
   (merge 96f6d3f61a rs/ls-files-partial-optim later to maint).

 * A hotfix for a topic already in 'master'.
   (merge a4d92d579f js/mingw-isatty later to maint).

 * Other minor doc, test and build updates and code cleanups.
   (merge f2627d9b19 sb/submodule-config-cleanup later to maint).
   (merge 384f1a167b sb/unpack-trees-cleanup later to maint).
   (merge 874444b704 rh/diff-orderfile-doc later to maint).
   (merge eafd5d9483 cw/doc-sign-off later to maint).
   (merge 0aaad415bc rs/absolute-pathdup later to maint).
   (merge 4432dd6b5b rs/receive-pack-cleanup later to maint).
   (merge 540a398e9c sg/mailmap-self later to maint).
   (merge 209df269a6 nd/rev-list-all-includes-HEAD-doc later to maint).
   (merge 941b9c5270 sb/doc-unify-bottom later to maint).
   (merge 2aaf37b62c jk/doc-remote-helpers-markup-fix later to maint).
   (merge e91461b332 jk/doc-submodule-markup-fix later to maint).
   (merge 8ab9740d9f dp/submodule-doc-markup-fix later to maint).
   (merge 0838cbc22f jk/tempfile-ferror-fclose-confusion later to maint).
   (merge 115a40add6 dr/doc-check-ref-format-normalize later to maint).
   (merge 133f0a299d gp/document-dotfiles-in-templates-are-not-copied later to maint).
   (merge 2b35a9f4c7 bc/blame-doc-fix later to maint).
   (merge 7e82388024 ps/doc-gc-aggressive-depth-update later to maint).
   (merge 9993a7c5f1 bc/worktree-doc-fix-detached later to maint).
   (merge e519eccdf4 rt/align-add-i-help-text later to maint).