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diff --git a/Documentation/RelNotes/2.20.0.txt b/Documentation/RelNotes/2.20.0.txt new file mode 100644 index 0000000000..519c89407c --- /dev/null +++ b/Documentation/RelNotes/2.20.0.txt @@ -0,0 +1,585 @@ +Git 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. + + * Developer builds now uses -Wunused-function compilation option. + + * One of our CI tests to run with "unusual/experimental/random" + settings now also uses commit-graph and midx. + + * "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). + + +Performance, Internal Implementation, Development Support etc. + + * 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 new extension to the index file has been introduced, which allows + 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 + 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. + + +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). + + * 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). + + * 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). + + * Code cleanup, docfix, build fix, etc. + (merge 96a7501aad ts/doc-build-manpage-xsl-quietly later to maint). + (merge b9b07efdb2 tg/conflict-marker-size later to maint). + (merge fa0aeea770 sg/doc-trace-appends later to maint). + (merge d64324cb60 tb/void-check-attr later to maint). + (merge c3b9bc94b9 en/double-semicolon-fix later to maint). + (merge 79336116f5 sg/t3701-tighten-trace later to maint). + (merge 801fa63a90 jk/dev-build-format-security later to maint). + (merge 0597dd62ba sb/string-list-remove-unused later to maint). + (merge db2d36fad8 bw/protocol-v2 later to maint). + (merge 456d7cd3a9 sg/split-index-test later to maint). + (merge 7b6057c852 tq/refs-internal-comment-fix later to maint). + (merge 29e8dc50ad tg/t5551-with-curl-7.61.1 later to maint). + (merge 55f6bce2c9 fe/doc-updates later to maint). + (merge 7987d2232d jk/check-everything-connected-is-long-gone later to maint). + (merge 4ba3c9be47 dz/credential-doc-url-matching-rules later to maint). + (merge 4c399442f7 ma/commit-graph-docs later to maint). + (merge fc0503b04e ma/t1400-undebug-test later to maint). + (merge e56b53553a nd/packobjectshook-doc-fix later to maint). + (merge c56170a0c4 ma/mailing-list-address-in-git-help later to maint). + (merge 6e8fc70fce rs/sequencer-oidset-insert-avoids-dups later to maint). + (merge ad0b8f9575 mw/doc-typofixes later to maint). + (merge d9f079ad1a jc/how-to-document-api later to maint). + (merge b1492bf315 ma/t7005-bash-workaround later to maint). + (merge ac1f98a0df du/rev-parse-is-plumbing later to maint). + (merge ca8ed443a5 mm/doc-no-dashed-git later to maint). + (merge ce366a8144 du/get-tar-commit-id-is-plumbing later to maint). + (merge 61018fe9e0 du/cherry-is-plumbing later to maint). + (merge c7e5fe79b9 sb/strbuf-h-update later to maint). + (merge 8d2008196b tq/branch-create-wo-branch-get later to maint). + (merge 2e3c894f4b tq/branch-style-fix later to maint). + (merge c5d844af9c sg/doc-show-branch-typofix later to maint). + (merge 081d91618b ah/doc-updates later to maint). + (merge b84c783882 jc/cocci-preincr later to maint). + (merge 5e495f8122 uk/merge-subtree-doc-update later to maint). + (merge aaaa881822 jk/uploadpack-packobjectshook-fix later to maint). + (merge 3063477445 tb/char-may-be-unsigned later to maint). + (merge 8c64bc9420 sg/test-rebase-editor-fix later to maint). + (merge 71571cd7d6 ma/sequencer-do-reset-saner-loop-termination later to maint). |