Git 2.11 Release Notes
======================

Updates since v2.10
-------------------

UI, Workflows & Features

 * "git format-patch --cover-letter HEAD^" to format a single patch
   with a separate cover letter now numbers the output as [PATCH 0/1]
   and [PATCH 1/1] by default.

 * An incoming "git push" that attempts to push too many bytes can now
   be rejected by setting a new configuration variable at the receiving
   end.

 * "git nosuchcommand --help" said "No manual entry for gitnosuchcommand",
   which was not intuitive, given that "git nosuchcommand" said "git:
   'nosuchcommand' is not a git command".

 * "git clone --resurse-submodules --reference $path $URL" is a way to
   reduce network transfer cost by borrowing objects in an existing
   $path repository when cloning the superproject from $URL; it
   learned to also peek into $path for presense of corresponding
   repositories of submodules and borrow objects from there when able.

 * The "git diff --submodule={short,log}" mechanism has been enhanced
   to allow "--submodule=diff" to show the patch between the submodule
   commits bound to the superproject.

 * Even though "git hash-objects", which is a tool to take an
   on-filesystem data stream and put it into the Git object store,
   allowed to perform the "outside-world-to-Git" conversions (e.g.
   end-of-line conversions and application of the clean-filter), and
   it had the feature on by default from very early days, its reverse
   operation "git cat-file", which takes an object from the Git object
   store and externalize for the consumption by the outside world,
   lacked an equivalent mechanism to run the "Git-to-outside-world"
   conversion.  The command learned the "--filters" option to do so.

 * Output from "git diff" can be made easier to read by selecting
   which lines are common and which lines are added/deleted
   intelligently when the lines before and after the changed section
   are the same.  A command line option is added to help with the
   experiment to find a good heuristics.

 * In some projects, it is common to use "[RFC PATCH]" as the subject
   prefix for a patch meant for discussion rather than application.  A
   new option "--rfc" was a short-hand for "--subject-prefix=RFC PATCH"
   to help the participants of such projects.

 * "git add --chmod=+x <pathspec>" added recently only toggled the
   executable bit for paths that are either new or modified. This has
   been corrected to flip the executable bit for all paths that match
   the given pathspec.

 * When "git format-patch --stdout" output is placed as an in-body
   header and it uses the RFC2822 header folding, "git am" failed to
   put the header line back into a single logical line.  The
   underlying "git mailinfo" was taught to handle this properly.


Performance, Internal Implementation, Development Support etc.

 * The delta-base-cache mechanism has been a key to the performance in
   a repository with a tightly packed packfile, but it did not scale
   well even with a larger value of core.deltaBaseCacheLimit.

 * Enhance "git status --porcelain" output by collecting more data on
   the state of the index and the working tree files, which may
   further be used to teach git-prompt (in contrib/) to make fewer
   calls to git.

 * Extract a small helper out of the function that reads the authors
   script file "git am" internally uses.
   (merge a77598e jc/am-read-author-file later to maint).

 * Lifts calls to exit(2) and die() higher in the callchain in
   sequencer.c files so that more helper functions in it can be used
   by callers that want to handle error conditions themselves.

 * "git am" has been taught to make an internal call to "git apply"'s
   innards without spawning the latter as a separate process.

 * The ref-store abstraction was introduced to the refs API so that we
   can plug in different backends to store references.

 * The "unsigned char sha1[20]" to "struct object_id" conversion
   continues.  Notable changes in this round includes that ce->sha1,
   i.e. the object name recorded in the cache_entry, turns into an
   object_id.

 * JGit can show a fake ref "capabilities^{}" to "git fetch" when it
   does not advertise any refs, but "git fetch" was not prepared to
   see such an advertisement.  When the other side disconnects without
   giving any ref advertisement, we used to say "there may not be a
   repository at that URL", but we may have seen other advertisement
   like "shallow" and ".have" in which case we definitely know that a
   repository is there.  The code to detect this case has also been
   updated.

 * Some codepaths in "git pack-objects" were not ready to use an
   existing pack bitmap; now they are and as the result they have
   become faster.


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).

 * Clarify various ways to specify the "revision ranges" in the
   documentation.

 * "diff-highlight" script (in contrib/) learned to work better with
   "git log -p --graph" output.

 * The test framework left the number of tests and success/failure
   count in the t/test-results directory, keyed by the name of the
   test script plus the process ID.  The latter however turned out not
   to serve any useful purpose.  The process ID part of the filename
   has been removed.

 * Having a submodule whose ".git" repository is somehow corrupt
   caused a few commands that recurse into submodules loop forever.

 * "git symbolic-ref -d HEAD" happily removes the symbolic ref, but
   the resulting repository becomes an invalid one.  Teach the command
   to forbid removal of HEAD.

 * A test spawned a short-lived background process, which sometimes
   prevented the test directory from getting removed at the end of the
   script on some platforms.

 * Update a few tests that used to use GIT_CURL_VERBOSE to use the
   newer GIT_TRACE_CURL.

 * "git pack-objects --include-tag" was taught that when we know that
   we are sending an object C, we want a tag B that directly points at
   C but also a tag A that points at the tag B.  We used to miss the
   intermediate tag B in some cases.
   (merge b773dde jk/pack-tag-of-tag later to maint).

 * Update Japanese translation for "git-gui".
   (merge 02748bc sy/git-gui-i18n-ja later to maint).

 * "git fetch http::/site/path" did not die correctly and segfaulted
   instead.
   (merge d63ed6e jk/fix-remote-curl-url-wo-proto later to maint).

 * "git commit-tree" stopped reading commit.gpgsign configuration
   variable that was meant for Porcelain "git commit" in Git 2.9; we
   forgot to update "git gui" to look at the configuration to match
   this change.
   (merge f14a310 js/git-gui-commit-gpgsign later to maint).

 * "git add --chmod=+x" added recently lacked documentation, which has
   been corrected.
   (merge 7ef7903 et/add-chmod-x later to maint).

 * "git log --cherry-pick" used to include merge commits as candidates
   to be matched up with other commits, resulting a lot of wasted time.
   The patch-id generation logic has been updated to ignore merges to
   avoid the wastage.
   (merge 7c81040 jk/patch-ids-no-merges later to maint).

 * The http transport (with curl-multi option, which is the default
   these days) failed to remove curl-easy handle from a curlm session,
   which led to unnecessary API failures.
   (merge 2abc848 ew/http-do-not-forget-to-call-curl-multi-remove-handle later to maint).

 * There were numerous corner cases in which the configuration files
   are read and used or not read at all depending on the directory a
   Git command was run, leading to inconsistent behaviour.  The code
   to set-up repository access at the beginning of a Git process has
   been updated to fix them.
   (merge 4d0efa1 jk/setup-sequence-update later to maint).

 * "git diff -W" output needs to extend the context backward to
   include the header line of the current function and also forward to
   include the body of the entire current function up to the header
   line of the next one.  This process may have to merge to adjacent
   hunks, but the code forgot to do so in some cases.
   (merge 45d2f75 rs/xdiff-merge-overlapping-hunks-for-W-context later to maint).

 * Performance tests done via "t/perf" did not use the same set of
   build configuration if the user relied on autoconf generated
   configuration.
   (merge cd5c281 ks/perf-build-with-autoconf later to maint).

 * "git format-patch --base=..." feature that was recently added
   showed the base commit information after "-- " e-mail signature
   line, which turned out to be inconvenient.  The base information
   has been moved above the signature line.
   (merge 480871e jt/format-patch-base-info-above-sig later to maint).

 * More i18n.
   (merge 43073f8 va/i18n later to maint).

 * Even when "git pull --rebase=preserve" (and the underlying "git
   rebase --preserve") can complete without creating any new commit
   (i.e. fast-forwards), it still insisted on having a usable ident
   information (read: user.email is set correctly), which was less
   than nice.  As the underlying commands used inside "git rebase"
   would fail with a more meaningful error message and advice text
   when the bogus ident matters, this extra check was removed.
   (merge 1e461c4 jk/rebase-i-drop-ident-check later to maint).

 * "git gc --aggressive" used to limit the delta-chain length to 250,
   which is way too deep for gaining additional space savings and is
   detrimental for runtime performance.  The limit has been reduced to
   50.
   (merge 07e7dbf jk/reduce-gc-aggressive-depth later to maint).

 * Documentation for individual configuration variables to control use
   of color (like `color.grep`) said that their default value is
   'false', instead of saying their default is taken from `color.ui`.
   When we updated the default value for color.ui from 'false' to
   'auto' quite a while ago, all of them broke.  This has been
   corrected.
   (merge 14d16e2 mm/config-color-ui-default-to-auto later to maint).

 * The pretty-format specifier "%C(auto)" used by the "log" family of
   commands to enable coloring of the output is taught to also issue a
   color-reset sequence to the output.
   (merge c99ad27 rs/c-auto-resets-attributes later to maint).

 * A shell script example in check-ref-format documentation has been
   fixed.
   (merge 92dece7 ep/doc-check-ref-format-example later to maint).

 * "git checkout <word>" does not follow the usual disambiguation
   rules when the <word> can be both a rev and a path, to allow
   checking out a branch 'foo' in a project that happens to have a
   file 'foo' in the working tree without having to disambiguate.
   This was poorly documented and the check was incorrect when the
   command was run from a subdirectory.
   (merge b829b94 nd/checkout-disambiguation later to maint).

 * Some codepaths in "git diff" used regexec(3) on a buffer that was
   mmap(2)ed, which may not have a terminating NUL, leading to a read
   beyond the end of the mapped region.  This was fixed by introducing
   a regexec_buf() helper that takes a <ptr,len> pair with REG_STARTEND
   extension.
   (merge b7d36ff js/regexec-buf later to maint).

 * The procedure to build Git on Mac OS X for Travis CI hardcoded the
   internal directory structure we assumed HomeBrew uses, which was a
   no-no.  The procedure has been updated to ask HomeBrew things we
   need to know to fix this.
   (merge f86f49b ls/travis-homebrew-path-fix later to maint).

 * When "git rebase -i" is given a broken instruction, it told the
   user to fix it with "--edit-todo", but didn't say what the step
   after that was (i.e. "--continue").
   (merge 37875b4 rt/rebase-i-broken-insn-advise later to maint).

 * Documentation around tools to import from CVS was fairly outdated.
   (merge 106b672 jk/doc-cvs-update later to maint).

 * "git clone --recurse-submodules" lost the progress eye-candy in
   recent update, which has been corrected.

 * A low-level function verify_packfile() was meant to show errors
   that were detected without dying itself, but under some conditions
   it didn't and died instead, which has been fixed.
   (merge a9445d859e jk/verify-packfile-gently later to maint).

 * When "git fetch" tries to find where the history of the repository
   it runs in has diverged from what the other side has, it has a
   mechanism to avoid digging too deep into irrelevant side branches.
   This however did not work well over the "smart-http" transport due
   to a design bug, which has been fixed.
   (merge 06b3d386e0 jt/fetch-pack-in-vain-count-with-stateless later to maint).

 * In the codepath that comes up with the hostname to be used in an
   e-mail when the user didn't tell us, we looked at ai_canonname
   field in struct addrinfo without making sure it is not NULL first.
   (merge c375a7efa3 jk/ident-ai-canonname-could-be-null later to maint).

 * "git worktree", even though it used the default_abbrev setting that
   ought to be affected by core.abbrev configuration variable, ignored
   the variable setting.  The command has been taught to read the
   default set of configuration variables to correct this.
   (merge d49028e6e7 jc/worktree-config later to maint).

 * Other minor doc, test and build updates and code cleanups.
   (merge e78d57e bw/pathspec-remove-unused-extern-decl later to maint).
   (merge ce25e4c rs/checkout-some-states-are-const later to maint).
   (merge a8342a4 rs/strbuf-remove-fix later to maint).
   (merge b56aa5b rs/unpack-trees-reduce-file-scope-global later to maint).
   (merge 5efc60c mr/vcs-svn-printf-ulong later to maint).
   (merge a22ae75 rs/cocci later to maint).