Log message:
Bump PKGREVISIONs for perl 5.30.0

Log message:
*: recursive bump for nettle 3.5.1

Log message:
Recursive revbump from boost-1.70.0

Log message:
Update to 2.22.0

Changelog:
Git 2.22 Release Notes
======================

Updates since v2.21
-------------------

Backward compatibility note

 * The filter specification "--filter=sparse:path=<path>" used to
   create a lazy/partial clone has been removed.  Using a blob that is
   part of the project as sparse specification is still supported with
   the "--filter=sparse:oid=<blob>" option.

UI, Workflows & Features

 * "git checkout --no-overlay" can be used to trigger a new mode of
   checking out paths out of the tree-ish, that allows paths that
   match the pathspec that are in the current index and working tree
   and are not in the tree-ish.

 * The %(trailers) formatter in "git log --format=..."  now allows to
   optionally pick trailers selectively by keyword, show only values,
   etc.

 * Four new configuration variables {author,committer}.{name,email}
   have been introduced to override user.{name,email} in more specific
   cases.

 * Command-line completion (in contrib/) learned to tab-complete the
   "git submodule absorbgitdirs" subcommand.

 * "git branch" learned a new subcommand "--show-current".

 * Output from "diff --cc" did not show the original paths when the
   merge involved renames.  A new option adds the paths in the
   original trees to the output.

 * The command line completion (in contrib/) has been taught to
   complete more subcommand parameters.

 * The final report from "git bisect" used to show the suspected
   culprit using a raw "diff-tree", with which there is no output for
   a merge commit.  This has been updated to use a more modern and
   human readable output that still is concise enough.

 * "git rebase --rebase-merges" replaces its old \ 
"--preserve-merges"
   option; the latter is now marked as deprecated.

 * Error message given while cloning with --recurse-submodules has
   been updated.

 * The completion helper code now pays attention to repository-local
   configuration (when available), which allows --list-cmds to honour
   a repository specific setting of completion.commands, for example.

 * "git mergetool" learned to offer Sublime Merge (smerge) as one of
   its backends.

 * A new hook "post-index-change" is called when the on-disk index
   file changes, which can help e.g. a virtualized working tree
   implementation.

 * "git difftool" can now run outside a repository.

 * "git checkout -m <other>" was about carrying the differences
   between HEAD and the working-tree files forward while checking out
   another branch, and ignored the differences between HEAD and the
   index.  The command has been taught to abort when the index and the
   HEAD are different.

 * A progress indicator has been added to the "index-pack" step, which
   often makes users wait for completion during "git clone".

 * "git submodule" learns "set-branch" subcommand that allows the
   submodule.*.branch settings to be modified.

 * "git merge-recursive" backend recently learned a new heuristics to
   infer file movement based on how other files in the same directory
   moved.  As this is inherently less robust heuristics than the one
   based on the content similarity of the file itself (rather than
   based on what its neighbours are doing), it sometimes gives an
   outcome unexpected by the end users.  This has been toned down to
   leave the renamed paths in higher/conflicted stages in the index so
   that the user can examine and confirm the result.

 * "git tag" learned to give an advice suggesting it might be a
   mistake when creating an annotated or signed tag that points at
   another tag.

 * The "git pack-objects" command learned to report the number of
   objects it packed via the trace2 mechanism.

 * The list of conflicted paths shown in the editor while concluding a
   conflicted merge was shown above the scissors line when the
   clean-up mode is set to "scissors", even though it was commented
   out just like the list of updated paths and other information to
   help the user explain the merge better.

 * The trace2 tracing facility learned to auto-generate a filename
   when told to log to a directory.

 * "git clone" learned a new --server-option option when talking over
   the protocol version 2.

 * The connectivity bitmaps are created by default in bare
   repositories now; also the pathname hash-cache is created by
   default to avoid making crappy deltas when repacking.

 * "git branch new A...B" and "git checkout -b new A...B" \ 
have been
   taught that in their contexts, the notation A...B means "the merge
   base between these two commits", just like "git checkout A...B"
   detaches HEAD at that commit.

 * Update "git difftool" and "git mergetool" so that the \ 
combinations
   of {diff,merge}.{tool,guitool} configuration variables serve as
   fallback settings of each other in a sensible order.

 * The "--dir-diff" mode of "git difftool" is not useful in \ 
"--no-index"
   mode; they are now explicitly marked as mutually incompatible.

Performance, Internal Implementation, Development Support etc.

 * The diff machinery, one of the oldest parts of the system, which
   long predates the parse-options API, uses fairly long and complex
   handcrafted option parser.  This is being rewritten to use the
   parse-options API.

 * The implementation of pack-redundant has been updated for
   performance in a repository with many packfiles.

 * A more structured way to obtain execution trace has been added.

 * "git prune" has been taught to take advantage of reachability
   bitmap when able.

 * The command line parser of "git commit-tree" has been rewritten to
   use the parse-options API.

 * Suggest GitGitGadget instead of submitGit as a way to submit
   patches based on GitHub PR to us.

 * The test framework has been updated to help developers by making it
   easier to run most of the tests under different versions of
   over-the-wire protocols.

 * Dev support update to make it easier to compare two formatted
   results from our documentation.

 * The scripted "git rebase" implementation has been retired.

 * "git multi-pack-index verify" did not scale well with the number of
   packfiles, which is being improved.

 * "git stash" has been rewritten in C.

 * The "check-docs" Makefile target to support developers has been
   updated.

 * The tests have been updated not to rely on the abbreviated option
   names the parse-options API offers, to protect us from an
   abbreviated form of an option that used to be unique within the
   command getting non-unique when a new option that share the same
   prefix is added.

 * The scripted version of "git rebase -i" wrote and rewrote the todo
   list many times during a single step of its operation, and the
   recent C-rewrite made a faithful conversion of the logic to C.  The
   implementation has been updated to carry necessary information
   around in-core to avoid rewriting the same file over and over
   unnecessarily.

 * Test framework update to more robustly clean up leftover files and
   processes after tests are done.

 * Conversion from unsigned char[20] to struct object_id continues.

 * While running "git diff" in a lazy clone, we can upfront know which
   missing blobs we will need, instead of waiting for the on-demand
   machinery to discover them one by one.  The code learned to aim to
   achieve better performance by batching the request for these
   promised blobs.

 * During an initial "git clone --depth=..." partial clone, it is
   pointless to spend cycles for a large portion of the connectivity
   check that enumerates and skips promisor objects (which by
   definition is all objects fetched from the other side).  This has
   been optimized out.

 * Mechanically and systematically drop "extern" from function
   declaration.

 * The script to aggregate perf result unconditionally depended on
   libjson-perl even though it did not have to, which has been
   corrected.

 * The internal implementation of "git rebase -i" has been updated to
   avoid forking a separate "rebase--interactive" process.

 * Allow DEP and ASLR for Windows build to for security hardening.

 * Performance test framework has been broken and measured the version
   of Git that happens to be on $PATH, not the specified one to
   measure, for a while, which has been corrected.

 * Optionally "make coccicheck" can feed multiple source files to
   spatch, gaining performance while spending more memory.

 * Attempt to use an abbreviated option in "git clone --recurs" is
   responded by a request to disambiguate between --recursive and
   --recurse-submodules, which is bad because these two are synonyms.
   The parse-options API has been extended to define such synonyms
   more easily and not produce an unnecessary failure.

 * A pair of private functions in http.c that had names similar to
   fread/fwrite did not return the number of elements, which was found
   to be confusing.

 * Update collision-detecting SHA-1 code to build properly on HP-UX.

Fixes since v2.21
-----------------

 * "git prune-packed" did not notice and complain against excess
   arguments given from the command line, which now it does.
   (merge 9b0bd87ed2 rj/prune-packed-excess-args later to maint).

 * Split-index fix.
   (merge 6e37c8ed3c nd/split-index-null-base-fix later to maint).

 * "git diff --no-index" may still want to access Git goodies like
   --ext-diff and --textconv, but so far these have been ignored,
   which has been corrected.
   (merge 287ab28bfa jk/diff-no-index-initialize later to maint).

 * Unify RPC code for smart http in protocol v0/v1 and v2, which fixes
   a bug in the latter (lack of authentication retry) and generally
   improves the code base.
   (merge a97d00799a jt/http-auth-proto-v2-fix later to maint).

 * The include file compat/bswap.h has been updated so that it is safe
   to (accidentally) include it more than once.
   (merge 33aa579a55 jk/guard-bswap-header later to maint).

 * The set of header files used by "make hdr-check" unconditionally
   included sha256/gcrypt.h, even when it is not used, causing the
   make target to fail.  We now skip it when GCRYPT_SHA256 is not in
   use.
   (merge f23aa18e7f rj/hdr-check-gcrypt-fix later to maint).

 * The Makefile uses 'find' utility to enumerate all the *.h header
   files, which is expensive on platforms with slow filesystems; it
   now optionally uses "ls-files" if working within a repository,
   which is a trick similar to how all sources are enumerated to run
   ETAGS on.
   (merge 92b88eba9f js/find-lib-h-with-ls-files-when-possible later to maint).

 * "git rebase" that was reimplemented in C did not set ORIG_HEAD
   correctly, which has been corrected.
   (merge cbd29ead92 js/rebase-orig-head-fix later to maint).

 * Dev support.
   (merge f545737144 js/stress-test-ui-tweak later to maint).

 * CFLAGS now can be tweaked when invoking Make while using
   DEVELOPER=YesPlease; this did not work well before.
   (merge 6d5d4b4e93 ab/makefile-help-devs-more later to maint).

 * "git fsck --connectivity-only" omits computation necessary to sift
   the objects that are not reachable from any of the refs into
   unreachable and dangling.  This is now enabled when dangling
   objects are requested (which is done by default, but can be
   overridden with the "--no-dangling" option).
   (merge 8d8c2a5aef jk/fsck-doc later to maint).

 * On platforms where "git fetch" is killed with SIGPIPE (e.g. OSX),
   the upload-pack that runs on the other end that hangs up after
   detecting an error could cause "git fetch" to die with a signal,
   which led to a flaky test.  "git fetch" now ignores SIGPIPE during
   the network portion of its operation (this is not a problem as we
   check the return status from our write(2)s).
   (merge 143588949c jk/no-sigpipe-during-network-transport later to maint).

 * A recent update broke "is this object available to us?" check for
   well-known objects like an empty tree (which should yield "yes",
   even when there is no on-disk object for an empty tree), which has
   been corrected.
   (merge f06ab027ef jk/virtual-objects-do-exist later to maint).

 * The setup code has been cleaned up to avoid leaks around the
   repository_format structure.
   (merge e8805af1c3 ma/clear-repository-format later to maint).

 * "git config --type=color ..." is meant to replace "git config \ 
--get-color"
   but there is a slight difference that wasn't documented, which is
   now fixed.
   (merge cd8e7593b9 jk/config-type-color-ends-with-lf later to maint).

 * When the "clean" filter can reduce the size of a huge file in the
   working tree down to a small "token" (a la Git LFS), there is no
   point in allocating a huge scratch area upfront, but the buffer is
   sized based on the original file size.  The convert mechanism now
   allocates very minimum and reallocates as it receives the output
   from the clean filter process.
   (merge 02156ab031 jh/resize-convert-scratch-buffer later to maint).

 * "git rebase" uses the refs/rewritten/ hierarchy to store its
   intermediate states, which inherently makes the hierarchy per
   worktree, but it didn't quite work well.
   (merge b9317d55a3 nd/rewritten-ref-is-per-worktree later to maint).

 * "git log -L<from>,<to>:<path>" with \ 
"-s" did not suppress the patch
   output as it should.  This has been corrected.
   (merge 05314efaea jk/line-log-with-patch later to maint).

 * "git worktree add" used to do a "find an available name with stat
   and then mkdir", which is race-prone.  This has been fixed by using
   mkdir and reacting to EEXIST in a loop.
   (merge 7af01f2367 ms/worktree-add-atomic-mkdir later to maint).

 * Build update for SHA-1 with collision detection.
   (merge 07a20f569b jk/sha1dc later to maint).

 * Build procedure has been fixed around use of asciidoctor instead of
   asciidoc.
   (merge 185f9a0ea0 ma/asciidoctor-fixes later to maint).

 * remote-http transport did not anonymize URLs reported in its error
   messages at places.
   (merge c1284b21f2 js/anonymize-remote-curl-diag later to maint).

 * Error messages given from the http transport have been updated so
   that they can be localized.
   (merge ed8b4132c8 js/remote-curl-i18n later to maint).

 * "git init" forgot to read platform-specific repository
   configuration, which made Windows port to ignore settings of
   core.hidedotfiles, for example.

 * A corner-case object name ambiguity while the sequencer machinery
   is working (e.g. "rebase -i -x") has been fixed.

 * "git format-patch" did not diagnose an error while opening the
   output file for the cover-letter, which has been corrected.
   (merge 2fe95f494c jc/format-patch-error-check later to maint).

 * "git checkout -f <branch>" while the index has an unmerged path
   incorrectly left some paths in an unmerged state, which has been
   corrected.

 * A corner case bug in the refs API has been corrected.
   (merge d3322eb28b jk/refs-double-abort later to maint).

 * Unicode update.
   (merge 584b62c37b bb/unicode-12 later to maint).

 * dumb-http walker has been updated to share more error recovery
   strategy with the normal codepath.

 * A buglet in configuration parser has been fixed.
   (merge 19e7fdaa58 nd/include-if-wildmatch later to maint).

 * The documentation for "git read-tree --reset -u" has been updated.
   (merge b5a0bd694c nd/read-tree-reset-doc later to maint).

 * Code clean-up around a much-less-important-than-it-used-to-be
   update_server_info() function.
   (merge b3223761c8 jk/server-info-rabbit-hole later to maint).

 * The message given when "git commit -a <paths>" errors out has been
   updated.
   (merge 5a1dbd48bc nd/commit-a-with-paths-msg-update later to maint).

 * "git cherry-pick --options A..B", after giving control back to the
   user to ask help resolving a conflicted step, did not honor the
   options it originally received, which has been corrected.

 * Various glitches in "git gc" around reflog handling have been fixed.

 * The code to read from commit-graph file has been cleanup with more
   careful error checking before using data read from it.

 * Performance fix around "git fetch" that grabs many refs.
   (merge b764300912 jt/fetch-pack-wanted-refs-optim later to maint).

 * Protocol v2 support in "git fetch-pack" of shallow clones has been
   corrected.

 * Performance fix around "git blame", especially in a linear history
   (which is the norm we should optimize for).
   (merge f892014943 dk/blame-keep-origin-blob later to maint).

 * Performance fix for "rev-list --parents -- pathspec".
   (merge 8320b1dbe7 jk/revision-rewritten-parents-in-prio-queue later to maint).

 * Updating the display with progress message has been cleaned up to
   deal better with overlong messages.
   (merge 545dc345eb sg/overlong-progress-fix later to maint).

 * "git blame -- path" in a non-bare repository starts blaming from
   the working tree, and the same command in a bare repository errors
   out because there is no working tree by definition.  The command
   has been taught to instead start blaming from the commit at HEAD,
   which is more useful.
   (merge a544fb08f8 sg/blame-in-bare-start-at-head later to maint).

 * An underallocation in the code to read the untracked cache
   extension has been corrected.
   (merge 3a7b45a623 js/untracked-cache-allocfix later to maint).

 * The code is updated to check the result of memory allocation before
   it is used in more places, by using xmalloc and/or xcalloc calls.
   (merge 999b951b28 jk/xmalloc later to maint).

 * The GETTEXT_POISON test option has been quite broken ever since it
   was made runtime-tunable, which has been fixed.
   (merge f88b9cb603 jc/gettext-test-fix later to maint).

 * Test fix on APFS that is incapable of store paths in Latin-1.
   (merge 3889149619 js/iso8895-test-on-apfs later to maint).

 * "git submodule foreach <command> --quiet" did not pass the option
   down correctly, which has been corrected.
   (merge a282f5a906 nd/submodule-foreach-quiet later to maint).

 * "git send-email" has been taught to use quoted-printable when the
   payload contains carriage-return.  The use of the mechanism is in
   line with the design originally added the codepath that chooses QP
   when the payload has overly long lines.
   (merge 74d76a1701 bc/send-email-qp-cr later to maint).

 * The recently added feature to add addresses that are on
   anything-by: trailers in 'git send-email' was found to be way too
   eager and considered nonsense strings as if they can be legitimate
   beginning of *-by: trailer.  This has been tightened.

 * Builds with gettext broke on recent macOS w/ Homebrew, which
   seems to have stopped including from /usr/local/include; this
   has been corrected.
   (merge 92a1377a2a js/macos-gettext-build later to maint).

 * Running "git add" on a repository created inside the current
   repository is an explicit indication that the user wants to add it
   as a submodule, but when the HEAD of the inner repository is on an
   unborn branch, it cannot be added as a submodule.  Worse, the files
   in its working tree can be added as if they are a part of the outer
   repository, which is not what the user wants.  These problems are
   being addressed.
   (merge f937bc2f86 km/empty-repo-is-still-a-repo later to maint).

 * "git cherry-pick" run with the "-x" or the \ 
"--signoff" option used
   to (and more importantly, ought to) clean up the commit log message
   with the --cleanup=space option by default, but this has been
   broken since late 2017.  This has been fixed.

 * When given a tag that points at a commit-ish, "git replace --graft"
   failed to peel the tag before writing a replace ref, which did not
   make sense because the old graft mechanism the feature wants to
   mimic only allowed to replace one commit object with another.
   This has been fixed.
   (merge ee521ec4cb cc/replace-graft-peel-tags later to maint).

 * Code tightening against a "wrong" object appearing where an object
   of a different type is expected, instead of blindly assuming that
   the connection between objects are correctly made.
   (merge 97dd512af7 tb/unexpected later to maint).

 * An earlier update for MinGW and Cygwin accidentally broke MSVC build,
   which has been fixed.
   (merge 22c3634c0f ss/msvc-path-utils-fix later to maint).

 * %(push:track) token used in the --format option to "git
   for-each-ref" and friends was not showing the right branch, which
   has been fixed.
   (merge c646d0934e dr/ref-filter-push-track-fix later to maint).

 * "make check-docs", "git help -a", etc. did not account \ 
for cases
   where a particular build may deliberately omit some subcommands,
   which has been corrected.

 * The logic to tell if a Git repository has a working tree protects
   "git branch -D" from removing the branch that is currently checked
   out by mistake.  The implementation of this logic was broken for
   repositories with unusual name, which unfortunately is the norm for
   submodules these days.  This has been fixed.
   (merge f3534c98e4 jt/submodule-repo-is-with-worktree later to maint).

 * AIX shared the same build issues with other BSDs around fileno(fp),
   which has been corrected.
   (merge ee662bf5c6 cc/aix-has-fileno-as-a-macro later to maint).

 * The autoconf generated configure script failed to use the right
   gettext() implementations from -libintl by ignoring useless stub
   implementations shipped in some C library, which has been
   corrected.
   (merge b71e56a683 vk/autoconf-gettext later to maint).

 * Fix index-pack perf test so that the repeated invocations always
   run in an empty repository, which emulates the initial clone
   situation better.
   (merge 775c71e16d jk/p5302-avoid-collision-check-cost later to maint).

 * A "ls-files" that emulates "find" to enumerate files in \ 
the working
   tree resulted in duplicated Makefile rules that caused the build to
   issue an unnecessary warning during a trial build after merge
   conflicts are resolved in working tree *.h files but before the
   resolved results are added to the index.  This has been corrected.

 * "git cherry-pick" (and "revert" that shares the same \ 
runtime engine)
   that deals with multiple commits got confused when the final step
   gets stopped with a conflict and the user concluded the sequence
   with "git commit".  Attempt to fix it by cleaning up the state
   files used by these commands in such a situation.
   (merge 4a72486de9 pw/clean-sequencer-state-upon-final-commit later to maint).

 * On a filesystem like HFS+, the names of the refs stored as filesystem
   entities may become different from what the end-user expects, just
   like files in the working tree get "renamed".  Work around the
   mismatch by paying attention to the core.precomposeUnicode
   configuration.
   (merge 8e712ef6fc en/unicode-in-refnames later to maint).

 * The code to generate the multi-pack idx file was not prepared to
   see too many packfiles and ran out of open file descriptor, which
   has been corrected.

 * To run tests for Git SVN, our scripts for CI used to install the
   git-svn package (in the hope that it would bring in the right
   dependencies).  This has been updated to install the more direct
   dependency, namely, libsvn-perl.
   (merge db864306cf sg/ci-libsvn-perl later to maint).

 * "git cvsexportcommit" running on msys did not expect cvsnt showed
   "cvs status" output with CRLF line endings.

 * The fsmonitor interface got out of sync after the in-core index
   file gets discarded, which has been corrected.
   (merge 398a3b0899 js/fsmonitor-refresh-after-discarding-index later to maint).

 * "git status" did not know that the "label" instruction in the
   todo-list "rebase -i -r" uses should not be shown as a hex object
   name.

 * A prerequisite check in the test suite to see if a working jgit is
   available was made more robust.
   (merge abd0f28983 tz/test-lib-check-working-jgit later to maint).

 * The codepath to parse :<path> that obtains the object name for an
   indexed object has been made more robust.

 * Code cleanup, docfix, build fix, etc.
   (merge 11f470aee7 jc/test-yes-doc later to maint).
   (merge 90503a240b js/doc-symref-in-proto-v1 later to maint).
   (merge 5c326d1252 jk/unused-params later to maint).
   (merge 68cabbfda3 dl/doc-submodule-wo-subcommand later to maint).
   (merge 9903623761 ab/receive-pack-use-after-free-fix later to maint).
   (merge 1ede45e44b en/merge-options-doc later to maint).
   (merge 3e14dd2c8e rd/doc-hook-used-in-sample later to maint).
   (merge c271dc28fd nd/no-more-check-racy later to maint).
   (merge e6e15194a8 yb/utf-16le-bom-spellfix later to maint).
   (merge bb101aaf0c rd/attr.c-comment-typofix later to maint).
   (merge 716a5af812 rd/gc-prune-doc-fix later to maint).
   (merge 50b206371d js/untravis-windows later to maint).
   (merge dbf47215e3 js/rebase-recreate-merge later to maint).
   (merge 56cb2d30f8 dl/reset-doc-no-wrt-abbrev later to maint).
   (merge 64eca306a2 ja/dir-rename-doc-markup-fix later to maint).
   (merge af91b0230c dl/ignore-docs later to maint).
   (merge 59a06e947b ra/t3600-test-path-funcs later to maint).
   (merge e041d0781b ar/t4150-remove-cruft later to maint).
   (merge 8d75a1d183 ma/asciidoctor-fixes-more later to maint).
   (merge 74cc547b0f mh/pack-protocol-doc-fix later to maint).
   (merge ed31851fa6 ab/doc-misc-typofixes later to maint).
   (merge a7256debd4 nd/checkout-m-doc-update later to maint).
   (merge 3a9e1ad78d jt/t5551-protocol-v2-does-not-have-half-auth later to maint).
   (merge 0b918b75af sg/t5318-cleanup later to maint).
   (merge 68ed71b53c cb/doco-mono later to maint).
   (merge a34dca2451 nd/interpret-trailers-docfix later to maint).
   (merge cf7b857a77 en/fast-import-parsing-fix later to maint).
   (merge fe61ccbc35 po/rerere-doc-fmt later to maint).
   (merge ffea0248bf po/describe-not-necessarily-7 later to maint).
   (merge 7cb7283adb tg/ls-files-debug-format-fix later to maint).
   (merge f64a21bd82 tz/doc-apostrophe-no-longer-needed later to maint).
   (merge dbe7b41019 js/t3301-unbreak-notes-test later to maint).
   (merge d8083e4180 km/t3000-retitle later to maint).
   (merge 9e4cbccbd7 tz/git-svn-doc-markup-fix later to maint).
   (merge da9ca955a7 jk/ls-files-doc-markup-fix later to maint).
   (merge 6804ba3a58 cw/diff-highlight later to maint).
   (merge 1a8787144d nd/submodule-helper-incomplete-line-fix later to maint).
   (merge d9ef573837 jk/apache-lsan later to maint).
   (merge c871fbee2b js/t6500-use-windows-pid-on-mingw later to maint).
   (merge ce4c7bfc90 bl/t4253-exit-code-from-format-patch later to maint).
   (merge 397a46db78 js/t5580-unc-alternate-test later to maint).
   (merge d4907720a2 cm/notes-comment-fix later to maint).
   (merge 9dde06de13 cb/http-push-null-in-message-fix later to maint).
   (merge 4c785c0edc js/rebase-config-bitfix later to maint).
   (merge 8e9fe16c87 es/doc-gitsubmodules-markup later to maint).

Log message:
git: updated to 2.21.0

Git 2.21 Release Notes
======================

Backward Compatibility Notes
----------------------------

 * Historically, the "-m" (mainline) option can only be used for "git
   cherry-pick" and "git revert" when working with a merge commit.
   This version of Git no longer warns or errors out when working with
   a single-parent commit, as long as the argument to the "-m" option
   is 1 (i.e. it has only one parent, and the request is to pick or
   revert relative to that first parent).  Scripts that relied on the
   behaviour may get broken with this change.

Updates since v2.20
-------------------

UI, Workflows & Features

 * The "http.version" configuration variable can be used with recent
   enough versions of cURL library to force the version of HTTP used
   to talk when fetching and pushing.

 * Small fixes and features for fast-export and fast-import, mostly on
   the fast-export side has been made.

 * "git push $there $src:$dst" rejects when $dst is not a fully
   qualified refname and it is not clear what the end user meant.  The
   codepath has been taught to give a clearer error message, and also
   guess where the push should go by taking the type of the pushed
   object into account (e.g. a tag object would want to go under
   refs/tags/).

 * "git checkout [<tree-ish>] path..." learned to report the \ 
number of
   paths that have been checked out of the index or the tree-ish,
   which gives it the same degree of noisy-ness as the case in which
   the command checks out a branch.  "git checkout -m <pathspec>" to
   undo conflict resolution gives a similar message.

 * "git quiltimport" learned "--keep-non-patch" option.

 * "git worktree remove" and "git worktree move" refused to \ 
work when
   there is a submodule involved.  This has been loosened to ignore
   uninitialized submodules.

 * "git cherry-pick -m1" was forbidden when picking a non-merge
   commit, even though there _is_ parent number 1 for such a commit.
   This was done to avoid mistakes back when "cherry-pick" was about
   picking a single commit, but is no longer useful with "cherry-pick"
   that can pick a range of commits.  Now the "-m$num" option is
   allowed when picking any commit, as long as $num names an existing
   parent of the commit.

 * Update "git multimail" from the upstream.

 * "git p4" update.

 * The "--format=<placeholder>" option of for-each-ref, branch \ 
and tag
   learned to show a few more traits of objects that can be learned by
   the object_info API.

 * "git rebase -i" learned to re-execute a command given with 'exec'
   to run after it failed the last time.

 * "git diff --color-moved-ws" updates.

 * Custom userformat "log --format" learned %S atom that stands for
   the tip the traversal reached the commit from, i.e. --source.

 * "git instaweb" learned to drive http.server that comes with
   "batteries included" Python installation (both Python2 & 3).

 * A new encoding UTF-16LE-BOM has been invented to force encoding to
   UTF-16 with BOM in little endian byte order, which cannot be directly
   generated by using iconv.

 * A new date format "--date=human" that morphs its output depending
   on how far the time is from the current time has been introduced.
   "--date=auto:human" can be used to use this new format (or any
   existing format) when the output is going to the pager or to the
   terminal, and otherwise the default format.

Performance, Internal Implementation, Development Support etc.

 * Code clean-up with optimization for the codepath that checks
   (non-)existence of loose objects.

 * More codepaths have become aware of working with in-core repository
   instances other than the default "the_repository".

 * The "strncat()" function is now among the banned functions.

 * Portability updates for the HPE NonStop platform.

 * Earlier we added "-Wformat-security" to developer builds, assuming
   that "-Wall" (which includes "-Wformat" which in turn is \ 
required
   to use "-Wformat-security") is always in effect.  This is not true
   when config.mak.autogen is in use, unfortunately.  This has been
   fixed by unconditionally adding "-Wall" to developer builds.

 * The loose object cache used to optimize existence look-up has been
   updated.

 * Flaky tests can now be repeatedly run under load with the
   "--stress" option.

 * Documentation/Makefile is getting prepared for manpage
   localization.

 * "git fetch-pack" now can talk the version 2 protocol.

 * sha-256 hash has been added and plumbed through the code to allow
   building Git with the "NewHash".

 * Debugging help for http transport.

 * "git fetch --deepen=<more>" has been corrected to work over v2
   protocol.

 * The code to walk tree objects has been taught that we may be
   working with object names that are not computed with SHA-1.

 * The in-core repository instances are passed through more codepaths.

 * Update the protocol message specification to allow only the limited
   use of scaled quantities.  This is to ensure potential compatibility
   issues will not get out of hand.

 * Micro-optimize the code that prepares commit objects to be walked
   by "git rev-list" when the commit-graph is available.

 * "git fetch" and "git upload-pack" learned to send all \ 
exchanges over
   the sideband channel while talking the v2 protocol.

 * The codepath to write out commit-graph has been optimized by
   following the usual pattern of visiting objects in in-pack order.

 * The codepath to show progress meter while writing out commit-graph
   file has been improved.

 * Cocci rules have been updated to encourage use of strbuf_addbuf().

 * "git rebase --merge" has been reimplemented by reusing the internal
   machinery used for "git rebase -i".

 * More code in "git bisect" has been rewritten in C.

 * Instead of going through "git-rebase--am" scriptlet to use the \ 
"am"
   backend, the built-in version of "git rebase" learned to drive the
   "am" backend directly.

 * The assumption to work on the single "in-core index" instance has
   been reduced from the library-ish part of the codebase.

 * The test lint learned to catch non-portable "sed" options.

 * "git pack-objects" learned another algorithm to compute the set of
   objects to send, that trades the resulting packfile off to save
   traversal cost to favor small pushes.

 * The travis CI scripts have been corrected to build Git with the
   compiler(s) of our choice.

 * "git submodule update" learned to abort early when core.worktree
   for the submodule is not set correctly to prevent spreading damage.

 * Test suite has been adjusted to run on Azure Pipeline.

 * Running "Documentation/doc-diff x" from anywhere other than the
   top-level of the working tree did not show the usage string
   correctly, which has been fixed.

 * Use of the sparse tool got easier to customize from the command
   line to help developers.

 * A new target "coverage-prove" to run the coverage test under
   "prove" has been added.

 * A flakey "p4" test has been removed.

 * The code and tests assume that the system supplied iconv() would
   always use BOM in its output when asked to encode to UTF-16 (or
   UTF-32), but apparently some implementations output big-endian
   without BOM.  A compile-time knob has been added to help such
   systems (e.g. NonStop) to add BOM to the output to increase
   portability.

Fixes since v2.20
-----------------

 * Updates for corner cases in merge-recursive.
   (merge cc4cb0902c en/merge-path-collision later to maint).

 * "git checkout frotz" (without any double-dash) avoids ambiguity by
   making sure 'frotz' cannot be interpreted as a revision and as a
   path at the same time.  This safety has been updated to check also
   a unique remote-tracking branch 'frotz' in a remote, when dwimming
   to create a local branch 'frotz' out of a remote-tracking branch
   'frotz' from a remote.
   (merge be4908f103 nd/checkout-dwim-fix later to maint).

 * Refspecs configured with "git -c var=val clone" did not propagate
   to the resulting repository, which has been corrected.
   (merge 7eae4a3ac4 sg/clone-initial-fetch-configuration later to maint).

 * A properly configured username/email is required under
   user.useConfigOnly in order to create commits; now "git stash"
   (even though it creates commit objects to represent stash entries)
   command is exempt from the requirement.
   (merge 3bc2111fc2 sd/stash-wo-user-name later to maint).

 * The http-backend CGI process did not correctly clean up the child
   processes it spawns to run upload-pack etc. when it dies itself,
   which has been corrected.
   (merge 02818a98d7 mk/http-backend-kill-children-before-exit later to maint).

 * "git rev-list --exclude-promisor-objects" had to take an object
   that does not exist locally (and is lazily available) from the
   command line without barfing, but the code dereferenced NULL.
   (merge 4cf67869b2 md/list-lazy-objects-fix later to maint).

 * The traversal over tree objects has learned to honor
   ":(attr:label)" pathspec match, which has been implemented only for
   enumerating paths on the filesystem.
   (merge 5a0b97b34c nd/attr-pathspec-in-tree-walk later to maint).

 * BSD port updates.
   (merge 4e3ecbd439 cb/openbsd-allows-reading-directory later to maint).
   (merge b6bdc2a0f5 cb/t5004-empty-tar-archive-fix later to maint).
   (merge 82cbc8cde2 cb/test-lint-cp-a later to maint).

 * Lines that begin with a certain keyword that come over the wire, as
   well as lines that consist only of one of these keywords, ought to
   be painted in color for easier eyeballing, but the latter was
   broken ever since the feature was introduced in 2.19, which has
   been corrected.
   (merge 1f67290450 hn/highlight-sideband-keywords later to maint).

 * "git log -G<regex>" looked for a hunk in the "git log \ 
-p" patch
   output that contained a string that matches the given pattern.
   Optimize this code to ignore binary files, which by default will
   not show any hunk that would match any pattern (unless textconv or
   the --text option is in effect, that is).
   (merge e0e7cb8080 tb/log-G-binary later to maint).

 * "git submodule update" ought to use a single job unless asked, but
   by mistake used multiple jobs, which has been fixed.
   (merge e3a9d1aca9 sb/submodule-fetchjobs-default-to-one later to maint).

 * "git stripspace" should be usable outside a git repository, but
   under the "-s" or "-c" mode, it didn't.
   (merge 957da75802 jn/stripspace-wo-repository later to maint).

 * Some of the documentation pages formatted incorrectly with
   Asciidoctor, which have been fixed.
   (merge b62eb1d2f4 ma/asciidoctor later to maint).

 * The core.worktree setting in a submodule repository should not be
   pointing at a directory when the submodule loses its working tree
   (e.g. getting deinit'ed), but the code did not properly maintain
   this invariant.

 * With zsh, "git cmd path<TAB>" was completed to "git cmd \ 
path name"
   when the completed path has a special character like SP in it,
   without any attempt to keep "path name" a single filename.  This
   has been fixed to complete it to "git cmd path\ name" just like
   Bash completion does.

 * The test suite tried to see if it is run under bash, but the check
   itself failed under some other implementations of shell (notably
   under NetBSD).  This has been corrected.
   (merge 54ea72f09c sg/test-bash-version-fix later to maint).

 * "git gc" and "git repack" did not close the open \ 
packfiles that
   they found unneeded before removing them, which didn't work on a
   platform incapable of removing an open file.  This has been
   corrected.
   (merge 5bdece0d70 js/gc-repack-close-before-remove later to maint).

 * The code to drive GIT_EXTERNAL_DIFF command relied on the string
   returned from getenv() to be non-volatile, which is not true, that
   has been corrected.
   (merge 6776a84dae kg/external-diff-save-env later to maint).

 * There were many places the code relied on the string returned from
   getenv() to be non-volatile, which is not true, that have been
   corrected.
   (merge 0da0e9268b jk/save-getenv-result later to maint).

 * The v2 upload-pack protocol implementation failed to honor
   hidden-ref configuration, which has been corrected.
   (merge e20b4192a3 jk/proto-v2-hidden-refs-fix later to maint).

 * "git fetch --recurse-submodules" may not fetch the necessary commit
   that is bound to the superproject, which is getting corrected.
   (merge be76c21282 sb/submodule-recursive-fetch-gets-the-tip later to maint).

 * "git rebase" internally runs "checkout" to switch between \ 
branches,
   and the command used to call the post-checkout hook, but the
   reimplementation stopped doing so, which is getting fixed.

 * "git add -e" got confused when the change it wants to let the user
   edit is smaller than the previous change that was left over in a
   temporary file.
   (merge fa6f225e01 js/add-e-clear-patch-before-stating later to maint).

 * "git p4" failed to update a shelved change when there were moved
   files, which has been corrected.
   (merge 7a10946ab9 ld/git-p4-shelve-update-fix later to maint).

 * The codepath to read from the commit-graph file attempted to read
   past the end of it when the file's table-of-contents was corrupt.

 * The compat/obstack code had casts that -Wcast-function-type
   compilation option found questionable.
   (merge 764473d257 sg/obstack-cast-function-type-fix later to maint).

 * An obvious typo in an assertion error message has been fixed.
   (merge 3c27e2e059 cc/test-ref-store-typofix later to maint).

 * In Git for Windows, "git clone \\server\share\path" etc. that uses
   UNC paths from command line had bad interaction with its shell
   emulation.

 * "git add --ignore-errors" did not work as advertised and instead
   worked as an unintended synonym for "git add --renormalize", which
   has been fixed.
   (merge e2c2a37545 jk/add-ignore-errors-bit-assignment-fix later to maint).

 * On a case-insensitive filesystem, we failed to compare the part of
   the path that is above the worktree directory in an absolute
   pathname, which has been corrected.

 * Asking "git check-attr" about a macro (e.g. "binary") on \ 
a specific
   path did not work correctly, even though "git check-attr -a" listed
   such a macro correctly.  This has been corrected.
   (merge 7b95849be4 jk/attr-macro-fix later to maint).

 * "git pack-objects" incorrectly used uninitialized mutex, which has
   been corrected.
   (merge edb673cf10 ph/pack-objects-mutex-fix later to maint).

 * "git checkout -b <new> [HEAD]" to create a new branch from the
   current commit and check it out ought to be a no-op in the index
   and the working tree in normal cases, but there are corner cases
   that do require updates to the index and the working tree.  Running
   it immediately after "git clone --no-checkout" is one of these
   cases that an earlier optimization kicked in incorrectly, which has
   been fixed.
   (merge 8424bfd45b bp/checkout-new-branch-optim later to maint).

 * "git diff --color-moved --cc --stat -p" did not work well due to
   funny interaction between a bug in color-moved and the rest, which
   has been fixed.
   (merge dac03b5518 jk/diff-cc-stat-fixes later to maint).

 * When GIT_SEQUENCE_EDITOR is set, the command was incorrectly
   started when modes of "git rebase" that implicitly uses the
   machinery for the interactive rebase are run, which has been
   corrected.
   (merge 891d4a0313 pw/no-editor-in-rebase-i-implicit later to maint).

 * The commit-graph facility did not work when in-core objects that
   are promoted from unknown type to commit (e.g. a commit that is
   accessed via a tag that refers to it) were involved, which has been
   corrected.
   (merge 4468d4435c sg/object-as-type-commit-graph-fix later to maint).

 * "git fetch" output cleanup.
   (merge dc40b24df4 nd/fetch-compact-update later to maint).

 * "git cat-file --batch" reported a dangling symbolic link by
   mistake, when it wanted to report that a given name is ambiguous.

 * Documentation around core.crlf has been updated.
   (merge c9446f0504 jk/autocrlf-overrides-eol-doc later to maint).

 * The documentation of "git commit-tree" said that the command
   understands "--gpg-sign" in addition to "-S", but the \ 
command line
   parser did not know about the longhand, which has been corrected.

 * "git rebase -x $cmd" did not reject multi-line command, even though
   the command is incapable of handling such a command.  It now is
   rejected upfront.
   (merge c762aada1a pw/rebase-x-sanity-check later to maint).

 * Output from "git help" was not correctly aligned, which has been
   fixed.
   (merge 6195a76da4 nd/help-align-command-desc later to maint).

 * The "git submodule summary" subcommand showed shortened commit
   object names by mechanically truncating them at 7-hexdigit, which
   has been improved to let "rev-parse --short" scale the length of
   the abbreviation with the size of the repository.
   (merge 0586a438f6 sh/submodule-summary-abbrev-fix later to maint).

 * The way the OSX build jobs updates its build environment used the
   "--quiet" option to "brew update" command, but it wasn't \ 
all that
   quiet to be useful.  The use of the option has been replaced with
   an explicit redirection to the /dev/null (which incidentally would
   have worked around a breakage by recent updates to homebrew, which
   has fixed itself already).
   (merge a1ccaedd62 sg/travis-osx-brew-breakage-workaround later to maint).

 * "git --work-tree=$there --git-dir=$here describe --dirty" did not
   work correctly as it did not pay attention to the location of the
   worktree specified by the user by mistake, which has been
   corrected.
   (merge c801170b0c ss/describe-dirty-in-the-right-directory later to maint).

 * "git fetch" over protocol v2 that needs to make a second connection
   to backfill tags did not clear a variable that holds shallow
   repository information correctly, leading to an access of freed
   piece of memory.

 * Some errors from the other side coming over smart HTTP transport
   were not noticed, which has been corrected.

 * Code cleanup, docfix, build fix, etc.

Log message:
git: updated to 2.20.1

Git v2.20.1:

This release is primarily to fix brown-paper-bag breakages in the
2.20.0 release.

Fixes since v2.20

 * A few newly added tests were not portable and caused minority
   platforms to report false breakages, which have been fixed.

 * Portability fix for a recent update to parse-options API.

 * "git help -a" did not work well when an overly long alias is
   defined, which has been corrected.

 * A recent update accidentally squelched an error message when the
   run_command API failed to run a missing command, which has been
   corrected.

Log message:
revbump for boost 1.69.0

Log message:
git: updated to 2.20.0

Git 2.20 Release Notes
======================

Backward Compatibility Notes
----------------------------

 * "git branch -l <foo>" used to be a way to ask a reflog to be
   created while creating a new branch, but that is no longer the
   case.  It is a short-hand for "git branch --list <foo>" now.

 * "git push" into refs/tags/* hierarchy is rejected without getting
   forced, but "git fetch" (misguidedly) used the "fast \ 
forwarding"
   rule used for the refs/heads/* hierarchy; this has been corrected,
   which means some fetches of tags that did not fail with older
   version of Git will fail without "--force" with this version.

 * "git help -a" now gives verbose output (same as "git help \ 
-av").
   Those who want the old output may say "git help --no-verbose -a"..

 * "git cpn --help", when "cpn" is an alias to, say, \ 
"cherry-pick -n",
   reported only the alias expansion of "cpn" in earlier versions of
   Git.  It now runs "git cherry-pick --help" to show the manual page
   of the command, while sending the alias expansion to the standard
   error stream.

 * "git send-email" learned to grab address-looking string on any
   trailer whose name ends with "-by". This is a backward-incompatible
   change.  Adding "--suppress-cc=misc-by" on the command line, or
   setting sendemail.suppresscc configuration variable to "misc-by",
   can be used to disable this behaviour.

Updates since v2.19
-------------------

UI, Workflows & Features

 * Running "git clone" against a project that contain two files with
   pathnames that differ only in cases on a case insensitive
   filesystem would result in one of the files lost because the
   underlying filesystem is incapable of holding both at the same
   time.  An attempt is made to detect such a case and warn.

 * "git checkout -b newbranch [HEAD]" should not have to do as much as
   checking out a commit different from HEAD.  An attempt is made to
   optimize this special case.

 * "git rev-list --stdin </dev/null" used to be an error; it now shows
   no output without an error.  "git rev-list --stdin --default HEAD"
   still falls back to the given default when nothing is given on the
   standard input.

 * Lift code from GitHub to restrict delta computation so that an
   object that exists in one fork is not made into a delta against
   another object that does not appear in the same forked repository.

 * "git format-patch" learned new "--interdiff" and \ 
"--range-diff"
   options to explain the difference between this version and the
   previous attempt in the cover letter (or after the three-dashes as
   a comment).

 * "git mailinfo" used in "git am" learned to make a best-effort
   recovery of a patch corrupted by MUA that sends text/plain with
   format=flawed option.
   (merge 3aa4d81f88 rs/mailinfo-format-flowed later to maint).

 * The rules used by "git push" and "git fetch" to determine \ 
if a ref
   can or cannot be updated were inconsistent; specifically, fetching
   to update existing tags were allowed even though tags are supposed
   to be unmoving anchoring points.  "git fetch" was taught to forbid
   updates to existing tags without the "--force" option.

 * "git multi-pack-index" learned to detect corruption in the .midx
   file it uses, and this feature has been integrated into "git fsck".

 * Generation of (experimental) commit-graph files have so far been
   fairly silent, even though it takes noticeable amount of time in a
   meaningfully large repository.  The users will now see progress
   output.

 * The minimum version of Windows supported by Windows port of Git is
   now set to Vista.

 * The completion script (in contrib/) learned to complete a handful of
   options "git stash list" command takes.

 * The completion script (in contrib/) learned that "git fetch
   --multiple" only takes remote names as arguments and no refspecs.

 * "git status" learns to show progress bar when refreshing the index
   takes a long time.
   (merge ae9af12287 nd/status-refresh-progress later to maint).

 * "git help -a" and "git help -av" give different pieces of
   information, and generally the "verbose" version is more friendly
   to the new users.  "git help -a" by default now uses the more
   verbose output (with "--no-verbose", you can go back to the
   original).  Also "git help -av" now lists aliases and external
   commands, which it did not used to.

 * Unlike "grep", "git grep" by default recurses to the \ 
whole tree.
   The command learned "git grep --recursive" option, so that "git
   grep --no-recursive" can serve as a synonym to setting the
   max-depth to 0.

 * When pushing into a repository that borrows its objects from an
   alternate object store, "git receive-pack" that responds to the
   push request on the other side lists the tips of refs in the
   alternate to reduce the amount of objects transferred.  This
   sometimes is detrimental when the number of refs in the alternate
   is absurdly large, in which case the bandwidth saved in potentially
   fewer objects transferred is wasted in excessively large ref
   advertisement.  The alternate refs that are advertised are now
   configurable with a pair of configuration variables.

 * "git cmd --help" when "cmd" is aliased used to only say \ 
"cmd is
   aliased to ...".  Now it shows that to the standard error stream
   and runs "git $cmd --help" where $cmd is the first word of the
   alias expansion.

 * The documentation of "git gc" has been updated to mention that it
   is no longer limited to "pruning away crufts" but also updates
   ancillary files like commit-graph as a part of repository
   optimization.

 * "git p4 unshelve" improvements.

 * The logic to select the default user name and e-mail on Windows has
   been improved.
   (merge 501afcb8b0 js/mingw-default-ident later to maint).

 * The "rev-list --filter" feature learned to exclude all trees via
   "tree:0" filter.

 * "git send-email" learned to grab address-looking string on any
   trailer whose name ends with "-by"; --suppress-cc=misc-by on the
   command line, or setting sendemail.suppresscc configuration
   variable to "misc-by", can be used to disable this behaviour.

 * "git mergetool" learned to take the "--[no-]gui" option, \ 
just like
   "git difftool" does.

 * "git rebase -i" learned a new insn, 'break', that the user can
   insert in the to-do list.  Upon hitting it, the command returns
   control back to the user.

 * New "--pretty=format:" placeholders %GF and %GP that show the GPG
   key fingerprints have been invented.

 * On platforms with recent cURL library, http.sslBackend configuration
   variable can be used to choose a different SSL backend at runtime.
   The Windows port uses this mechanism to switch between OpenSSL and
   Secure Channel while talking over the HTTPS protocol.

 * "git send-email" learned to disable SMTP authentication via the
   "--smtp-auth=none" option, even when the smtp username is given
   (which turns the authentication on by default).

 * A fourth class of configuration files (in addition to the
   traditional "system wide", "per user in the $HOME \ 
directory" and
   "per repository in the $GIT_DIR/config") has been introduced so
   that different worktrees that share the same repository (hence the
   same $GIT_DIR/config file) can use different customization.

 * A pattern with '**' that does not have a slash on either side used
   to be an invalid one, but the code now treats such double-asterisks
   the same way as two normal asterisks that happen to be adjacent to
   each other.
   (merge e5bbe09e88 nd/wildmatch-double-asterisk later to maint).

 * The "--no-patch" option, which can be used to get a high-level
   overview without the actual line-by-line patch difference shown, of
   the "range-diff" command was earlier broken, which has been
   corrected.

 * The recently merged "rebase in C" has an escape hatch to use the
   scripted version when necessary, but it hasn't been documented,
   which has been corrected.

Performance, Internal Implementation, Development Support etc.

 * Developer builds now use -Wunused-function compilation option.

 * One of our CI tests to run with "unusual/experimental/random"
   settings now also uses commit-graph and midx.

 * When there are too many packfiles in a repository (which is not
   recommended), looking up an object in these would require
   consulting many pack .idx files; a new mechanism to have a single
   file that consolidates all of these .idx files is introduced.

 * "git submodule update" is getting rewritten piece-by-piece into C.

 * The code for computing history reachability has been shuffled,
   obtained a bunch of new tests to cover them, and then being
   improved.

 * The unpack_trees() API used in checking out a branch and merging
   walks one or more trees along with the index.  When the cache-tree
   in the index tells us that we are walking a tree whose flattened
   contents is known (i.e. matches a span in the index), as linearly
   scanning a span in the index is much more efficient than having to
   open tree objects recursively and listing their entries, the walk
   can be optimized, which has been done.

 * When creating a thin pack, which allows objects to be made into a
   delta against another object that is not in the resulting pack but
   is known to be present on the receiving end, the code learned to
   take advantage of the reachability bitmap; this allows the server
   to send a delta against a base beyond the "boundary" commit.

 * spatch transformation to replace boolean uses of !hashcmp() to
   newly introduced oideq() is added, and applied, to regain
   performance lost due to support of multiple hash algorithms.

 * Fix a bug in which the same path could be registered under multiple
   worktree entries if the path was missing (for instance, was removed
   manually).  Also, as a convenience, expand the number of cases in
   which --force is applicable.

 * Split Documentation/config.txt for easier maintenance.
   (merge 6014363f0b nd/config-split later to maint).

 * Test helper binaries clean-up.
   (merge c9a1f4161f nd/test-tool later to maint).

 * Various tests have been updated to make it easier to swap the
   hash function used for object identification.
   (merge ae0c89d41b bc/hash-independent-tests later to maint).

 * Update fsck.skipList implementation and documentation.
   (merge 371a655074 ab/fsck-skiplist later to maint).

 * An alias that expands to another alias has so far been forbidden,
   but now it is allowed to create such an alias.

 * Various test scripts have been updated for style and also correct
   handling of exit status of various commands.

 * "gc --auto" ended up calling exit(-1) upon error, which has been
   corrected to use exit(1).  Also the error reporting behaviour when
   daemonized has been updated to exit with zero status when stopping
   due to a previously discovered error (which implies there is no
   point running gc to improve the situation); we used to exit with
   failure in such a case.

 * Various codepaths in the core-ish part learned to work on an
   arbitrary in-core index structure, not necessarily the default
   instance "the_index".
   (merge b3c7eef9b0 nd/the-index later to maint).

 * Code clean-up in the internal machinery used by "git status" and
   "git commit --dry-run".
   (merge 73ba5d78b4 ss/wt-status-committable later to maint).

 * Some environment variables that control the runtime options of Git
   used during tests are getting renamed for consistency.
   (merge 4231d1ba99 bp/rename-test-env-var later to maint).

 * A pair of new extensions to the index file have been introduced.
   They allow the index file to be read in parallel for performance.

 * The oidset API was built on top of the oidmap API which in turn is
   on the hashmap API.  Replace the implementation to build on top of
   the khash API and gain performance.

 * Over some transports, fetching objects with an exact commit object
   name can be done without first seeing the ref advertisements.  The
   code has been optimized to exploit this.

 * In a partial clone that will lazily be hydrated from the
   originating repository, we generally want to avoid "does this
   object exist (locally)?" on objects that we deliberately omitted
   when we created the clone.  The cache-tree codepath (which is used
   to write a tree object out of the index) however insisted that the
   object exists, even for paths that are outside of the partial
   checkout area.  The code has been updated to avoid such a check.

 * To help developers, an EditorConfig file that attempts to follow
   the project convention has been added.
   (merge b548d698a0 bc/editorconfig later to maint).

 * The result of coverage test can be combined with "git blame" to
   check the test coverage of code introduced recently with a new
   'coverage-diff' tool (in contrib/).
   (merge 783faedd65 ds/coverage-diff later to maint).

 * An experiment to fuzz test a few areas, hopefully we can gain more
   coverage to various areas.

 * More codepaths are moving away from hardcoded hash sizes.

 * The way the Windows port figures out the current directory has been
   improved.

 * The way DLLs are loaded on the Windows port has been improved.

 * Some tests have been reorganized and renamed; "ls t/" now gives a
   better overview of what is tested for these scripts than before.

 * "git rebase" and "git rebase -i" have been reimplemented in C.

 * Windows port learned to use nano-second resolution file timestamps.

 * The overly large Documentation/config.txt file have been split into
   million little pieces.  This potentially allows each individual piece
   to be included into the manual page of the command it affects more easily.

 * Replace three string-list instances used as look-up tables in "git
   fetch" with hashmaps.

 * Unify code to read the author-script used in "git am" and the
   commands that use the sequencer machinery, e.g. "git rebase -i".

 * In preparation to the day when we can deprecate and remove the
   "rebase -p", make sure we can skip and later remove tests for
   it.

 * The history traversal used to implement the tag-following has been
   optimized by introducing a new helper.

 * The helper function to refresh the cached stat information in the
   in-core index has learned to perform the lstat() part of the
   operation in parallel on multi-core platforms.

 * The code to traverse objects for reachability, used to decide what
   objects are unreferenced and expendable, have been taught to also
   consider per-worktree refs of other worktrees as starting points to
   prevent data loss.

 * "git add" needs to internally run "diff-files" \ 
equivalent, and the
   codepath learned the same optimization as "diff-files" has to run
   lstat(2) in parallel to find which paths have been updated in the
   working tree.

 * The procedure to install dependencies before testing at Travis CI
   is getting revamped for both simplicity and flexibility, taking
   advantage of the recent move to the vm-based environment.

 * The support for format-patch (and send-email) by the command-line
   completion script (in contrib/) has been simplified a bit.

 * The revision walker machinery learned to take advantage of the
   commit generation numbers stored in the commit-graph file.

 * The codebase has been cleaned up to reduce "#ifndef NO_PTHREADS".

 * The way -lcurl library gets linked has been simplified by taking
   advantage of the fact that we can just ask curl-config command how.

 * Various functions have been audited for "-Wunused-parameter" warnings
   and bugs in them got fixed.

 * A sanity check for start-up sequence has been added in the config
   API codepath.

 * The build procedure to link for fuzzing test has been made
   customizable with a new Makefile variable.

 * The way "git rebase" parses and forwards the command line options
   meant for underlying "git am" has been revamped, which fixed for
   options with parameters that were not passed correctly.

 * Our testing framework uses a special i18n "poisoned localization"
   feature to find messages that ought to stay constant but are
   incorrectly marked to be translated.  This feature has been made
   into a runtime option (it used to be a compile-time option).

 * "git push" used to check ambiguities between object-names and
   refnames while processing the list of refs' old and new values,
   which was unnecessary (as it knew that it is feeding raw object
   names).  This has been optimized out.

 * The xcurl_off_t() helper function is used to cast size_t to
   curl_off_t, but some compilers gave warnings against the code to
   ensure the casting is done without wraparound, when size_t is
   narrower than curl_off_t.  This warning has been squelched.

 * Code preparation to replace ulong vars with size_t vars where
   appropriate continues.

 * The "test installed Git" mode of our test suite has been updated to
   work better.

 * A coding convention around the Coccinelle semantic patches to have
   two classes to ease code migration process has been proposed and
   its support has been added to the Makefile.

 * The "container" mode of TravisCI is going away.  Our .travis.yml
   file is getting prepared for the transition.
   (merge 32ee384be8 ss/travis-ci-force-vm-mode later to maint).

 * Our test scripts can now take the '-V' option as a synonym for the
   '--verbose-log' option.
   (merge a5f52c6dab sg/test-verbose-log later to maint).

Fixes since v2.19
-----------------

 * "git interpret-trailers" and its underlying machinery had a buggy
   code that attempted to ignore patch text after commit log message,
   which triggered in various codepaths that will always get the log
   message alone and never get such an input.
   (merge 66e83d9b41 jk/trailer-fixes later to maint).

 * Malformed or crafted data in packstream can make our code attempt
   to read or write past the allocated buffer and abort, instead of
   reporting an error, which has been fixed.

 * "git rebase -i" did not clear the state files correctly when a run
   of "squash/fixup" is aborted and then the user manually amended the
   commit instead, which has been corrected.
   (merge 10d2f35436 js/rebase-i-autosquash-fix later to maint).

 * When fsmonitor is in use, after operation on submodules updates
   .gitmodules, we lost track of the fact that we did so and relied on
   stale fsmonitor data.
   (merge 43f1180814 bp/mv-submodules-with-fsmonitor later to maint).

 * Fix for a long-standing bug that leaves the index file corrupt when
   it shrinks during a partial commit.
   (merge 6c003d6ffb jk/reopen-tempfile-truncate later to maint).

 * Further fix for O_APPEND emulation on Windows
   (merge eeaf7ddac7 js/mingw-o-append later to maint).

 * A corner case bugfix in "git rerere" code.
   (merge ad2bf0d9b4 en/rerere-multi-stage-1-fix later to maint).

 * "git add ':(attr:foo)'" is not supported and is supposed to be
   rejected while the command line arguments are parsed, but we fail
   to reject such a command line upfront.
   (merge 84d938b732 nd/attr-pathspec-fix later to maint).

 * Recent update broke the reachability algorithm when refs (e.g.
   tags) that point at objects that are not commit were involved,
   which has been fixed.

 * "git rebase" etc. in Git 2.19 fails to abort when given an empty
   commit log message as result of editing, which has been corrected.
   (merge a3ec9eaf38 en/sequencer-empty-edit-result-aborts later to maint).

 * The code to backfill objects in lazily cloned repository did not
   work correctly, which has been corrected.
   (merge e68302011c jt/lazy-object-fetch-fix later to maint).

 * Update error messages given by "git remote" and make them consistent.
   (merge 5025425dff ms/remote-error-message-update later to maint).

 * "git update-ref" learned to make both "--no-deref" and \ 
"--stdin"
   work at the same time.
   (merge d345e9fbe7 en/update-ref-no-deref-stdin later to maint).

 * Recently added "range-diff" had a corner-case bug to cause it
   segfault, which has been corrected.
   (merge e467a90c7a tg/range-diff-corner-case-fix later to maint).

 * The recently introduced commit-graph auxiliary data is incompatible
   with mechanisms such as replace & grafts that "breaks" immutable
   nature of the object reference relationship.  Disable optimizations
   based on its use (and updating existing commit-graph) when these
   incompatible features are in use in the repository.
   (merge 829a321569 ds/commit-graph-with-grafts later to maint).

 * The mailmap file update.
   (merge 255eb03edf jn/mailmap-update later to maint).

 * The code in "git status" sometimes hit an assertion failure.  This
   was caused by a structure that was reused without cleaning the data
   used for the first run, which has been corrected.
   (merge 3e73cc62c0 en/status-multiple-renames-to-the-same-target-fix later to \ 
maint).

 * "git fetch $repo $object" in a partial clone did not correctly
   fetch the asked-for object that is referenced by an object in
   promisor packfile, which has been fixed.

 * A corner-case bugfix.
   (merge c5cbb27cb5 sm/show-superproject-while-conflicted later to maint).

 * Various fixes to "diff --color-moved-ws".

 * A partial clone that is configured to lazily fetch missing objects
   will on-demand issue a "git fetch" request to the originating
   repository to fill not-yet-obtained objects.  The request has been
   optimized for requesting a tree object (and not the leaf blob
   objects contained in it) by telling the originating repository that
   no blobs are needed.
   (merge 4c7f9567ea jt/non-blob-lazy-fetch later to maint).

 * The codepath to support the experimental split-index mode had
   remaining "racily clean" issues fixed.
   (merge 4c490f3d32 sg/split-index-racefix later to maint).

 * "git log --graph" showing an octopus merge sometimes miscounted the
   number of display columns it is consuming to show the merge and its
   parent commits, which has been corrected.
   (merge 04005834ed np/log-graph-octopus-fix later to maint).

 * "git range-diff" did not work well when the compared ranges had
   changes in submodules and the "--submodule=log" was used.

 * The implementation of run_command() API on the UNIX platforms had a
   bug that caused a command not on $PATH to be found in the current
   directory.
   (merge f67b980771 jk/run-command-notdot later to maint).

 * A mutex used in "git pack-objects" were not correctly initialized
   and this caused "git repack" to dump core on Windows.
   (merge 34204c8166 js/pack-objects-mutex-init-fix later to maint).

 * Under certain circumstances, "git diff D:/a/b/c D:/a/b/d" on
   Windows would strip initial parts from the paths because they
   were not recognized as absolute, which has been corrected.
   (merge ffd04e92e2 js/diff-notice-has-drive-prefix later to maint).

 * The receive.denyCurrentBranch=updateInstead codepath kicked in even
   when the push should have been rejected due to other reasons, such
   as it does not fast-forward or the update-hook rejects it, which
   has been corrected.
   (merge b072a25fad jc/receive-deny-current-branch-fix later to maint).

 * The logic to determine the archive type "git archive" uses did not
   correctly kick in for "git archive --remote", which has been
   corrected.

 * "git repack" in a shallow clone did not correctly update the
   shallow points in the repository, leading to a repository that
   does not pass fsck.
   (merge 5dcfbf564c js/shallow-and-fetch-prune later to maint).

 * Some codepaths failed to form a proper URL when .gitmodules record
   the URL to a submodule repository as relative to the repository of
   superproject, which has been corrected.
   (merge e0a862fdaf sb/submodule-url-to-absolute later to maint).

 * "git fetch" over protocol v2 into a shallow repository failed to
   fetch full history behind a new tip of history that was diverged
   before the cut-off point of the history that was previously fetched
   shallowly.

 * The command line completion machinery (in contrib/) has been
   updated to allow the completion script to tweak the list of options
   that are reported by the parse-options machinery correctly.
   (merge 276b49ff34 nd/completion-negation later to maint).

 * Operations on promisor objects make sense in the context of only a
   small subset of the commands that internally use the revisions
   machinery, but the "--exclude-promisor-objects" option were taken
   and led to nonsense results by commands like "log", to which it
   didn't make much sense.  This has been corrected.
   (merge 669b1d2aae md/exclude-promisor-objects-fix later to maint).

 * A regression in Git 2.12 era made "git fsck" fall into an infinite
   loop while processing truncated loose objects.
   (merge 18ad13e5b2 jk/detect-truncated-zlib-input later to maint).

 * "git ls-remote $there foo" was broken by recent update for the
   protocol v2 and stopped showing refs that match 'foo' that are not
   refs/{heads,tags}/foo, which has been fixed.
   (merge 6a139cdd74 jk/proto-v2-ref-prefix-fix later to maint).

 * Additional comment on a tricky piece of code to help developers.
   (merge 0afbe3e806 jk/stream-pack-non-delta-clarification later to maint).

 * A couple of tests used to leave the repository in a state that is
   deliberately corrupt, which have been corrected.
   (merge aa984dbe5e ab/pack-tests-cleanup later to maint).

 * The submodule support has been updated to read from the blob at
   HEAD:.gitmodules when the .gitmodules file is missing from the
   working tree.
   (merge 2b1257e463 ao/submodule-wo-gitmodules-checked-out later to maint).

 * "git fetch" was a bit loose in parsing responses from the other side
   when talking over the protocol v2.

 * "git rev-parse --exclude=* --branches --branches"  (i.e. first
   saying "add only things that do not match '*' out of all branches"
   and then adding all branches, without any exclusion this time)
   worked as expected, but "--exclude=* --all --all" did not work the
   same way, which has been fixed.
   (merge 5221048092 ag/rev-parse-all-exclude-fix later to maint).

 * "git send-email --transfer-encoding=..." in recent versions of Git
   sometimes produced an empty "Content-Transfer-Encoding:" header,
   which has been corrected.
   (merge 3c88e46f1a al/send-email-auto-cte-fixup later to maint).

 * The interface into "xdiff" library used to discover the offset and
   size of a generated patch hunk by first formatting it into the
   textual hunk header "@@ -n,m +k,l @@" and then parsing the numbers
   out.  A new interface has been introduced to allow callers a more
   direct access to them.
   (merge 5eade0746e jk/xdiff-interface later to maint).

 * Pathspec matching against a tree object were buggy when negative
   pathspec elements were involved, which has been fixed.
   (merge b7845cebc0 nd/tree-walk-path-exclusion later to maint).

 * "git merge" and "git pull" that merges into an unborn \ 
branch used
   to completely ignore "--verify-signatures", which has been
   corrected.
   (merge 01a31f3bca jk/verify-sig-merge-into-void later to maint).

 * "git rebase --autostash" did not correctly re-attach the HEAD at times.

 * "rev-parse --exclude=<pattern> --branches=<pattern>" \ 
etc. did not
   quite work, which has been corrected.
   (merge 9ab9b5df0e ra/rev-parse-exclude-glob later to maint).

 * When editing a patch in a "git add -i" session, a hunk could be
   made to no-op.  The "git apply" program used to reject a patch with
   such a no-op hunk to catch user mistakes, but it is now updated to
   explicitly allow a no-op hunk in an edited patch.
   (merge 22cb3835b9 js/apply-recount-allow-noop later to maint).

 * The URL to an MSDN page in a comment has been updated.
   (merge 2ef2ae2917 js/mingw-msdn-url later to maint).

 * "git ls-remote --sort=<thing>" can feed an object that is not yet
   available into the comparison machinery and segfault, which has
   been corrected to check such a request upfront and reject it.

 * When "git bundle" aborts due to an empty commit ranges
   (i.e. resulting in an empty pack), it left a file descriptor to an
   lockfile open, which resulted in leftover lockfile on Windows where
   you cannot remove a file with an open file descriptor.  This has
   been corrected.
   (merge 2c8ee1f53c jk/close-duped-fd-before-unlock-for-bundle later to maint).

 * "git format-patch --stat=<width>" can be used to specify the width
   used by the diffstat (shown in the cover letter).
   (merge 284aeb7e60 nd/format-patch-cover-letter-stat-width later to maint).

 * The way .git/index and .git/sharedindex* files were initially
   created gave these files different perm bits until they were
   adjusted for shared repository settings.  This was made consistent.
   (merge c9d6c78870 cc/shared-index-permbits later to maint).

 * "git rebase --stat" to transplant a piece of history onto a totally
   unrelated history were not working before and silently showed wrong
   result.  With the recent reimplementation in C, it started to instead
   die with an error message, as the original logic was not prepared
   to cope with this case.  This has now been fixed.

 * The advice message to tell the user to migrate an existing graft
   file to the replace system when a graft file was read was shown
   even when "git replace --convert-graft-file" command, which is the
   way the message suggests to use, was running, which made little
   sense.
   (merge 8821e90a09 ab/replace-graft-with-replace-advice later to maint).

 * "git diff --raw" lost ellipses to adjust the output columns for
   some time now, but the documentation still showed them.

 * Code cleanup, docfix, build fix, etc.