Git v2.42 Release Notes
=======================

UI, Workflows & Features

 * "git pack-refs" learns "--include" and "--exclude" to tweak the ref
   hierarchy to be packed using pattern matching.

 * 'git worktree add' learned how to create a worktree based on an
   orphaned branch with `--orphan`.

 * "git pack-objects" learned to invoke a new hook program that
   enumerates extra objects to be used as anchoring points to keep
   otherwise unreachable objects in cruft packs.

 * Add more "git var" for toolsmiths to learn various locations Git is
   configured with either via the configuration or hardcoded defaults.

 * 'git notes append' was taught '--separator' to specify string to insert
   between paragraphs.

 * The "git for-each-ref" family of commands learned placeholders
   related to GPG signature verification.

 * "git diff --no-index" learned to read from named pipes as if they
   were regular files, to allow "git diff <(process) <(substitution)"
   some shells support.

 * Help newbies by suggesting that there are cases where force-pushing
   is a valid and sensible thing to update a branch at a remote
   repository, rather than reconciling with merge/rebase.

 * "git blame --contents=file" has been taught to work in a bare
   repository.

 * "git branch -f X" to repoint the branch X said that X was "checked
   out" in another worktree, even when branch X was not and instead
   being bisected or rebased.  The message was reworded to say the
   branch was "in use".


Performance, Internal Implementation, Development Support etc.

 * "git diff-tree" has been taught to take advantage of the
   sparse-index feature.

 * Clang's sanitizer implementation seems to work better than GCC's.
   (merge d88d727143 jk/ci-use-clang-for-sanitizer-jobs later to maint).

 * The object traversal using reachability bitmap done by
   "pack-object" has been tweaked to take advantage of the fact that
   using "boundary" commits as representative of all the uninteresting
   ones can save quite a lot of object enumeration.

 * discover_git_directory() no longer touches the_repository.

 * "git worktree" learned to work better with sparse index feature.

 * When the external merge driver is killed by a signal, its output
   should not be trusted as a resolution with conflicts that is
   proposed by the driver, but the code did.

 * The set-up code for the get_revision() API now allows feeding
   options like --all and --not in the --stdin mode.

 * Move functions that are not about pure string manipulation out of
   strbuf.[ch]

 * "imap-send" codepaths got cleaned up to get rid of unused
   parameters.

 * Enumerating refs in the packed-refs file, while excluding refs that
   match certain patterns, has been optimized.

 * Mark-up unused parameters in the code so that we can eventually
   enable -Wunused-parameter by default.

 * Instead of inventing a custom counter variables for debugging,
   use existing trace2 facility in the fsync customization codepath.

 * "git branch --list --format=<format>" and friends are taught
   a new "%(describe)" placeholder.

 * Clarify how to choose the starting point for a new topic in
   developer guidance document.

 * The implementation of "get_sha1_hex()" that reads a hexadecimal
   string that spells a full object name has been extended to cope
   with any hash function used in the repository, but the "sha1" in
   its name survived.  Rename it to get_hash_hex(), a name that is
   more consistent within its friends like get_hash_hex_algop().

 * Command line parser fix, and a small parse-options API update.


Fixes since v2.41
-----------------

 * "git tag" learned to leave the "$GIT_DIR/TAG_EDITMSG" file when the
   command failed, so that the user can salvage what they typed.
   (merge 08c12ec1d0 kh/keep-tag-editmsg-upon-failure later to maint).

 * The "-s" (silent, squelch) option of the "diff" family of commands
   did not interact with other options that specify the output format
   well.  This has been cleaned up so that it will clear all the
   formatting options given before.
   (merge 9d484b92ed jc/diff-s-with-other-options later to maint).

 * Update documentation regarding Coccinelle patches.
   (merge 3bd0097cfc gc/doc-cocci-updates later to maint).

 * Some atoms that can be used in "--format=<format>" for "git ls-tree"
   were not supported by "git ls-files", even though they were relevant
   in the context of the latter.
   (merge 4d28c4f75f zh/ls-files-format-atoms later to maint).

 * Document more pseudo-refs and teach the command line completion
   machinery to complete AUTO_MERGE.
   (merge 982ff3a649 pb/complete-and-document-auto-merge-and-friends later to maint).

 * "git submodule" code trusted the data coming from the config (and
   the in-tree .gitmodules file) too much without validating, leading
   to NULL dereference if the user mucks with a repository (e.g.
   submodule.<name>.url is removed).  This has been corrected.
   (merge fbc806acd1 tb/submodule-null-deref-fix later to maint).

 * The value of config.worktree is per-repository, but has been kept
   in a singleton global variable per process. This has been OK as
   most Git operations interacted with a single repository at a time,
   but not right for operations like recursive "grep" that want to
   access multiple repositories from a single process without forking.

   The global variable has been eliminated and made into a member in
   the per-repository data structure.
   (merge 3867f6d650 vd/worktree-config-is-per-repository later to maint).

 * "git [-c log.follow=true] log [--follow] ':(glob)f**'" used to barf.
   (merge 8260bc5902 jk/log-follow-with-non-literal-pathspec later to maint).

 * Introduce a mechanism to disable replace refs globally and per
   repository.
   (merge 9c7d1b057f ds/disable-replace-refs later to maint).

 * "git cat-file --batch" and friends learned "-Z" that uses NUL
   delimiter for both input and output.
   (merge f79e18849b ps/cat-file-null-output later to maint).

 * The reimplemented "git add -i" did not honor color.ui configuration.
   (merge 6f74648cea ds/add-i-color-configuration-fix later to maint).

 * Compilation fix for platforms without D_TYPE in struct dirent.
   (merge 03bf92b9bf as/dtype-compilation-fix later to maint).

 * Suggest to refrain from using hex literals that are non-portable
   when writing printf(1) format strings.
   (merge f0b68f0546 jt/doc-use-octal-with-printf later to maint).

 * Simplify error message when run-command fails to start a command.
   (merge 6d224ac286 rs/run-command-exec-error-on-noent later to maint).

 * Gracefully deal with a stale MIDX file that lists a packfile that
   no longer exists.
   (merge 06f3867865 tb/open-midx-bitmap-fallback later to maint).

 * Even when diff.ignoreSubmodules tells us to ignore submodule
   changes, "git commit" with an index that already records changes to
   submodules should include the submodule changes in the resulting
   commit, but it did not.
   (merge 5768478edc js/defeat-ignore-submodules-config-with-explicit-addition later to maint).

 * When "git commit --trailer=..." invokes the interpret-trailers
   machinery, it knows what it feeds to interpret-trailers is a full
   log message without any patch, but failed to express that by
   passing the "--no-divider" option, which has been corrected.
   (merge be3d654343 jk/commit-use-no-divider-with-interpret-trailers later to maint).

 * Avoid breakage of "git pack-objects --cruft" due to inconsistency
   between the way the code enumerates packfiles in the repository.
   (merge 73320e49ad tb/collect-pack-filenames-fix later to maint).

 * We create .pack and then .idx, we consider only packfiles that have
   .idx usable (those with only .pack are not ready yet), so we should
   remove .idx before removing .pack for consistency.
   (merge 0dd1324a73 ds/remove-idx-before-pack later to maint).

 * Partially revert a sanity check that the rest of the config code
   was not ready, to avoid triggering it in a corner case.
   (merge a53f43f900 gc/config-partial-submodule-kvi-fix later to maint).

 * "git apply" punts when it is fed too large a patch input; the error
   message it gives when it happens has been clarified.
   (merge 42612e18d2 pw/apply-too-large later to maint).

 * During a cherry-pick or revert session that works on multiple
   commits, "git status" did not give correct information, which has
   been corrected.
   (merge a096a889f4 jk/cherry-pick-revert-status later to maint).

 * A few places failed to differentiate the case where the index is
   truly empty (nothing added) and we haven't yet read from the
   on-disk index file, which have been corrected.
   (merge 2ee045eea1 js/empty-index-fixes later to maint).

 * "git bugreport" tests did not test what it wanted to test, which
   has been corrected.
   (merge 1aa92b8500 ma/t0091-fixup later to maint).

 * Code snippets in a tutorial document no longer compiled after
   recent header shuffling, which have been corrected.
   (merge bbd7c7b7c0 vd/adjust-mfow-doc-to-updated-headers later to maint).

 * "git ls-files '(attr:X)D/'" that triggers the common prefix
   optimization codepath failed to read from "D/.gitattributes",
   which has been corrected.
   (merge f4a8fde057 jc/pathspec-match-with-common-prefix later to maint).

 * "git fsck --no-progress" still spewed noise from the commit-graph
   subsystem, which has been corrected.
   (merge 9281cd07f0 tb/fsck-no-progress later to maint).

 * Various offset computation in the code that accesses the packfiles
   and other data in the object layer has been hardened against
   arithmetic overflow, especially on 32-bit systems.
   (merge 9a25cad7e0 tb/object-access-overflow-protection later to maint).

 * Names of MinGW header files are spelled in mixed case in some
   source files, but the build host can be using case sensitive
   filesystem with header files with their name spelled in all
   lowercase.
   (merge 4a53d0d0bc mh/mingw-case-sensitive-build later to maint).

 * Update message mark-up for i18n in "git bundle".
   (merge bbb6acd998 dk/bundle-i18n-more later to maint).

 * "git tag --list --points-at X" showed tags that directly refers to
   object X, but did not list a tag that points at such a tag, which
   has been corrected.

 * "./configure --with-expat=no" did not work as a way to refuse use
   of the expat library on a system with the library installed, which
   has been corrected.
   (merge fb8f7269c2 ah/autoconf-fixes later to maint).

 * When the user edits "rebase -i" todo file so that it starts with a
   "fixup", which would make it invalid, the command truncated the
   rest of the file before giving an error and returning the control
   back to the user.  Stop truncating to make it easier to correct
   such a malformed todo file.
   (merge 9645a087c2 ah/sequencer-rewrite-todo-fix later to maint).

 * Rewrite the description of giving a custom command to the
   submodule.<name>.update configuration variable.
   (merge 7cebc5bd78 pv/doc-submodule-update-settings later to maint).

 * Other code cleanup, docfix, build fix, etc.
   (merge 51f9d2e563 sa/doc-ls-remote later to maint).
   (merge c6d26a9dda jk/format-patch-message-id-unleak later to maint).
   (merge f7e063f326 ps/fetch-cleanups later to maint).
   (merge e4cf013468 tl/quote-problematic-arg-for-clarity later to maint).
   (merge 20025fdfc7 tz/test-ssh-verifytime-fix later to maint).
   (merge e48a21df65 tz/test-fix-pthreads-prereq later to maint).
   (merge 68b51172e3 mh/commit-reach-get-reachable-plug-leak later to maint).
   (merge aeee1408ce kh/use-default-notes-doc later to maint).
   (merge 3b8724bce6 jc/test-modernization later to maint).
   (merge 447a3b7331 jc/test-modernization-2 later to maint).
   (merge d57fa7fc73 la/doc-interpret-trailers later to maint).
   (merge 548afb0d9a la/docs-typofixes later to maint).
   (merge 3744ffcbcd rs/doc-ls-tree-hex-literal later to maint).
   (merge 6c26da8404 mh/credential-erase-improvements later to maint).
   (merge 78e56cff69 tz/lib-gpg-prereq-fix later to maint).
   (merge 80d32e84b5 rj/leakfixes later to maint).
   (merge 0a868031ed pb/complete-diff-options later to maint).
   (merge d4f28279ad jc/doc-hash-object-types later to maint).
   (merge 1876a5ae15 ks/t4205-test-describe-with-abbrev-fix later to maint).
   (merge 6e6a529b57 jk/fsck-indices-in-worktrees later to maint).
   (merge 3e81b896f7 rs/packet-length-simplify later to maint).
   (merge 4c9cb51fe7 mh/doc-credential-helpers later to maint).
   (merge 3437f549dd jr/gitignore-doc-example-markup later to maint).
   (merge 947ebd62a0 jc/am-parseopt-fix later to maint).
   (merge e12cb98e1e jc/branch-parseopt-fix later to maint).
   (merge d6f598e443 jc/gitignore-doc-pattern-markup later to maint).
   (merge a2dad4868b jc/transport-parseopt-fix later to maint).
   (merge 68cbb20e73 jc/parse-options-show-branch later to maint).
   (merge 3821eb6c3d jc/parse-options-reset later to maint).
   (merge c48af99a3e bb/trace2-comment-fix later to maint).
   (merge c95ae3ff9c rs/describe-parseopt-fix later to maint).
   (merge 36f76d2a25 rs/pack-objects-parseopt-fix later to maint).
   (merge 30c8c55cbf jc/tree-walk-drop-base-offset later to maint).