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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..ab631660f9 --- /dev/null +++ b/Documentation/RelNotes/2.20.0.txt @@ -0,0 +1,315 @@ +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".. + + +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 tree-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 fo 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. + + +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. + + +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). + + * 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). |