4 Backward Compatibility Notes
5 ----------------------------
7 * "git branch -l <foo>" used to be a way to ask a reflog to be
8 created while creating a new branch, but that is no longer the
9 case. It is a short-hand for "git branch --list <foo>" now.
11 * "git push" into refs/tags/* hierarchy is rejected without getting
12 forced, but "git fetch" (misguidedly) used the "fast forwarding"
13 rule used for the refs/heads/* hierarchy; this has been corrected,
14 which means some fetches of tags that did not fail with older
15 version of Git will fail without "--force" with this version.
17 * "git help -a" now gives verbose output (same as "git help -av").
18 Those who want the old output may say "git help --no-verbose -a"..
20 * "git cpn --help", when "cpn" is an alias to, say, "cherry-pick -n",
21 reported only the alias expansion of "cpn" in earlier versions of
22 Git. It now runs "git cherry-pick --help" to show the manual page
23 of the command, while sending the alias expansion to the standard
26 * "git send-email" learned to grab address-looking string on any
27 trailer whose name ends with "-by". This is a backward-incompatible
28 change. Adding "--suppress-cc=misc-by" on the command line, or
29 setting sendemail.suppresscc configuration variable to "misc-by",
30 can be used to disable this behaviour.
36 UI, Workflows & Features
38 * Running "git clone" against a project that contain two files with
39 pathnames that differ only in cases on a case insensitive
40 filesystem would result in one of the files lost because the
41 underlying filesystem is incapable of holding both at the same
42 time. An attempt is made to detect such a case and warn.
44 * "git checkout -b newbranch [HEAD]" should not have to do as much as
45 checking out a commit different from HEAD. An attempt is made to
46 optimize this special case.
48 * "git rev-list --stdin </dev/null" used to be an error; it now shows
49 no output without an error. "git rev-list --stdin --default HEAD"
50 still falls back to the given default when nothing is given on the
53 * Lift code from GitHub to restrict delta computation so that an
54 object that exists in one fork is not made into a delta against
55 another object that does not appear in the same forked repository.
57 * "git format-patch" learned new "--interdiff" and "--range-diff"
58 options to explain the difference between this version and the
59 previous attempt in the cover letter (or after the three-dashes as
62 * "git mailinfo" used in "git am" learned to make a best-effort
63 recovery of a patch corrupted by MUA that sends text/plain with
65 (merge 3aa4d81f88 rs/mailinfo-format-flowed later to maint).
67 * The rules used by "git push" and "git fetch" to determine if a ref
68 can or cannot be updated were inconsistent; specifically, fetching
69 to update existing tags were allowed even though tags are supposed
70 to be unmoving anchoring points. "git fetch" was taught to forbid
71 updates to existing tags without the "--force" option.
73 * "git multi-pack-index" learned to detect corruption in the .midx
74 file it uses, and this feature has been integrated into "git fsck".
76 * Generation of (experimental) commit-graph files have so far been
77 fairly silent, even though it takes noticeable amount of time in a
78 meaningfully large repository. The users will now see progress
81 * The minimum version of Windows supported by Windows port of Git is
84 * The completion script (in contrib/) learned to complete a handful of
85 options "git stash list" command takes.
87 * The completion script (in contrib/) learned that "git fetch
88 --multiple" only takes remote names as arguments and no refspecs.
90 * "git status" learns to show progress bar when refreshing the index
92 (merge ae9af12287 nd/status-refresh-progress later to maint).
94 * "git help -a" and "git help -av" give different pieces of
95 information, and generally the "verbose" version is more friendly
96 to the new users. "git help -a" by default now uses the more
97 verbose output (with "--no-verbose", you can go back to the
98 original). Also "git help -av" now lists aliases and external
99 commands, which it did not used to.
101 * Unlike "grep", "git grep" by default recurses to the whole tree.
102 The command learned "git grep --recursive" option, so that "git
103 grep --no-recursive" can serve as a synonym to setting the
106 * When pushing into a repository that borrows its objects from an
107 alternate object store, "git receive-pack" that responds to the
108 push request on the other side lists the tips of refs in the
109 alternate to reduce the amount of objects transferred. This
110 sometimes is detrimental when the number of refs in the alternate
111 is absurdly large, in which case the bandwidth saved in potentially
112 fewer objects transferred is wasted in excessively large ref
113 advertisement. The alternate refs that are advertised are now
114 configurable with a pair of configuration variables.
116 * "git cmd --help" when "cmd" is aliased used to only say "cmd is
117 aliased to ...". Now it shows that to the standard error stream
118 and runs "git $cmd --help" where $cmd is the first word of the
121 * The documentation of "git gc" has been updated to mention that it
122 is no longer limited to "pruning away crufts" but also updates
123 ancillary files like commit-graph as a part of repository
126 * "git p4 unshelve" improvements.
128 * The logic to select the default user name and e-mail on Windows has
130 (merge 501afcb8b0 js/mingw-default-ident later to maint).
132 * The "rev-list --filter" feature learned to exclude all trees via
135 * "git send-email" learned to grab address-looking string on any
136 trailer whose name ends with "-by"; --suppress-cc=misc-by on the
137 command line, or setting sendemail.suppresscc configuration
138 variable to "misc-by", can be used to disable this behaviour.
140 * Developer builds now uses -Wunused-function compilation option.
142 * One of our CI tests to run with "unusual/experimental/random"
143 settings now also uses commit-graph and midx.
145 * "git mergetool" learned to take the "--[no-]gui" option, just like
148 * "git rebase -i" learned a new insn, 'break', that the user can
149 insert in the to-do list. Upon hitting it, the command returns
150 control back to the user.
152 * New "--pretty=format:" placeholders %GF and %GP that show the GPG
153 key fingerprints have been invented.
155 * On platforms with recent cURL library, http.sslBackend configuration
156 variable can be used to choose a different SSL backend at runtime.
157 The Windows port uses this mechanism to switch between OpenSSL and
158 Secure Channel while talking over the HTTPS protocol.
160 * "git send-email" learned to disable SMTP authentication via the
161 "--smtp-auth=none" option, even when the smtp username is given
162 (which turns the authentication on by default).
165 Performance, Internal Implementation, Development Support etc.
167 * When there are too many packfiles in a repository (which is not
168 recommended), looking up an object in these would require
169 consulting many pack .idx files; a new mechanism to have a single
170 file that consolidates all of these .idx files is introduced.
172 * "git submodule update" is getting rewritten piece-by-piece into C.
174 * The code for computing history reachability has been shuffled,
175 obtained a bunch of new tests to cover them, and then being
178 * The unpack_trees() API used in checking out a branch and merging
179 walks one or more trees along with the index. When the cache-tree
180 in the index tells us that we are walking a tree whose flattened
181 contents is known (i.e. matches a span in the index), as linearly
182 scanning a span in the index is much more efficient than having to
183 open tree objects recursively and listing their entries, the walk
184 can be optimized, which has been done.
186 * When creating a thin pack, which allows objects to be made into a
187 delta against another object that is not in the resulting pack but
188 is known to be present on the receiving end, the code learned to
189 take advantage of the reachability bitmap; this allows the server
190 to send a delta against a base beyond the "boundary" commit.
192 * spatch transformation to replace boolean uses of !hashcmp() to
193 newly introduced oideq() is added, and applied, to regain
194 performance lost due to support of multiple hash algorithms.
196 * Fix a bug in which the same path could be registered under multiple
197 worktree entries if the path was missing (for instance, was removed
198 manually). Also, as a convenience, expand the number of cases in
199 which --force is applicable.
201 * Split Documentation/config.txt for easier maintenance.
202 (merge 6014363f0b nd/config-split later to maint).
204 * Test helper binaries clean-up.
205 (merge c9a1f4161f nd/test-tool later to maint).
207 * Various tests have been updated to make it easier to swap the
208 hash function used for object identification.
209 (merge ae0c89d41b bc/hash-independent-tests later to maint).
211 * Update fsck.skipList implementation and documentation.
212 (merge 371a655074 ab/fsck-skiplist later to maint).
214 * An alias that expands to another alias has so far been forbidden,
215 but now it is allowed to create such an alias.
217 * Various test scripts have been updated for style and also correct
218 handling of exit status of various commands.
220 * "gc --auto" ended up calling exit(-1) upon error, which has been
221 corrected to use exit(1). Also the error reporting behaviour when
222 daemonized has been updated to exit with zero status when stopping
223 due to a previously discovered error (which implies there is no
224 point running gc to improve the situation); we used to exit with
225 failure in such a case.
227 * Various codepaths in the core-ish part learned to work on an
228 arbitrary in-core index structure, not necessarily the default
229 instance "the_index".
230 (merge b3c7eef9b0 nd/the-index later to maint).
232 * Code clean-up in the internal machinery used by "git status" and
233 "git commit --dry-run".
234 (merge 73ba5d78b4 ss/wt-status-committable later to maint).
236 * Some environment variables that control the runtime options of Git
237 used during tests are getting renamed for consistency.
238 (merge 4231d1ba99 bp/rename-test-env-var later to maint).
240 * A new extension to the index file has been introduced, which allows
241 the index file to be read in parallel for performance.
243 * The oidset API was built on top of the oidmap API which in turn is
244 on the hashmap API. Replace the implementation to build on top of
245 the khash API and gain performance.
247 * Over some transports, fetching objects with an exact commit object
248 name can be done without first seeing the ref advertisements. The
249 code has been optimized to exploit this.
251 * In a partial clone that will lazily be hydrated from the
252 originating repository, we generally want to avoid "does this
253 object exist (locally)?" on objects that we deliberately omitted
254 when we created the clone. The cache-tree codepath (which is used
255 to write a tree object out of the index) however insisted that the
256 object exists, even for paths that are outside of the partial
257 checkout area. The code has been updated to avoid such a check.
259 * To help developers, an EditorConfig file that attempts to follow
260 the project convention has been added.
261 (merge b548d698a0 bc/editorconfig later to maint).
263 * The result of coverage test can be combined with "git blame" to
264 check the test coverage of code introduced recently with a new
265 'coverage-diff' tool (in contrib/).
266 (merge 783faedd65 ds/coverage-diff later to maint).
268 * An experiment to fuzz test a few areas, hopefully we can gain more
269 coverage to various areas.
271 * More codepaths are moving away from hardcoded hash sizes.
273 * The way the Windows port figures out the current directory has been
276 * The way DLLs are loaded on the Windows port has been improved.
278 * Some tests have been reorganized and renamed; "ls t/" now gives a
279 better overview of what is tested for these scripts than before.
281 * "git rebase" and "git rebase -i" have been reimplemented in C.
283 * Windows port learned to use nano-second resolution file timestamps.
289 * "git interpret-trailers" and its underlying machinery had a buggy
290 code that attempted to ignore patch text after commit log message,
291 which triggered in various codepaths that will always get the log
292 message alone and never get such an input.
293 (merge 66e83d9b41 jk/trailer-fixes later to maint).
295 * Malformed or crafted data in packstream can make our code attempt
296 to read or write past the allocated buffer and abort, instead of
297 reporting an error, which has been fixed.
299 * "git rebase -i" did not clear the state files correctly when a run
300 of "squash/fixup" is aborted and then the user manually amended the
301 commit instead, which has been corrected.
302 (merge 10d2f35436 js/rebase-i-autosquash-fix later to maint).
304 * When fsmonitor is in use, after operation on submodules updates
305 .gitmodules, we lost track of the fact that we did so and relied on
306 stale fsmonitor data.
307 (merge 43f1180814 bp/mv-submodules-with-fsmonitor later to maint).
309 * Fix for a long-standing bug that leaves the index file corrupt when
310 it shrinks during a partial commit.
311 (merge 6c003d6ffb jk/reopen-tempfile-truncate later to maint).
313 * Further fix for O_APPEND emulation on Windows
314 (merge eeaf7ddac7 js/mingw-o-append later to maint).
316 * A corner case bugfix in "git rerere" code.
317 (merge ad2bf0d9b4 en/rerere-multi-stage-1-fix later to maint).
319 * "git add ':(attr:foo)'" is not supported and is supposed to be
320 rejected while the command line arguments are parsed, but we fail
321 to reject such a command line upfront.
322 (merge 84d938b732 nd/attr-pathspec-fix later to maint).
324 * Recent update broke the reachability algorithm when refs (e.g.
325 tags) that point at objects that are not commit were involved,
326 which has been fixed.
328 * "git rebase" etc. in Git 2.19 fails to abort when given an empty
329 commit log message as result of editing, which has been corrected.
330 (merge a3ec9eaf38 en/sequencer-empty-edit-result-aborts later to maint).
332 * The code to backfill objects in lazily cloned repository did not
333 work correctly, which has been corrected.
334 (merge e68302011c jt/lazy-object-fetch-fix later to maint).
336 * Update error messages given by "git remote" and make them consistent.
337 (merge 5025425dff ms/remote-error-message-update later to maint).
339 * "git update-ref" learned to make both "--no-deref" and "--stdin"
340 work at the same time.
341 (merge d345e9fbe7 en/update-ref-no-deref-stdin later to maint).
343 * Recently added "range-diff" had a corner-case bug to cause it
344 segfault, which has been corrected.
345 (merge e467a90c7a tg/range-diff-corner-case-fix later to maint).
347 * The recently introduced commit-graph auxiliary data is incompatible
348 with mechanisms such as replace & grafts that "breaks" immutable
349 nature of the object reference relationship. Disable optimizations
350 based on its use (and updating existing commit-graph) when these
351 incompatible features are in use in the repository.
352 (merge 829a321569 ds/commit-graph-with-grafts later to maint).
354 * The mailmap file update.
355 (merge 255eb03edf jn/mailmap-update later to maint).
357 * The code in "git status" sometimes hit an assertion failure. This
358 was caused by a structure that was reused without cleaning the data
359 used for the first run, which has been corrected.
360 (merge 3e73cc62c0 en/status-multiple-renames-to-the-same-target-fix later to maint).
362 * "git fetch $repo $object" in a partial clone did not correctly
363 fetch the asked-for object that is referenced by an object in
364 promisor packfile, which has been fixed.
366 * A corner-case bugfix.
367 (merge c5cbb27cb5 sm/show-superproject-while-conflicted later to maint).
369 * Various fixes to "diff --color-moved-ws".
371 * A partial clone that is configured to lazily fetch missing objects
372 will on-demand issue a "git fetch" request to the originating
373 repository to fill not-yet-obtained objects. The request has been
374 optimized for requesting a tree object (and not the leaf blob
375 objects contained in it) by telling the originating repository that
377 (merge 4c7f9567ea jt/non-blob-lazy-fetch later to maint).
379 * The codepath to support the experimental split-index mode had
380 remaining "racily clean" issues fixed.
381 (merge 4c490f3d32 sg/split-index-racefix later to maint).
383 * "git log --graph" showing an octopus merge sometimes miscounted the
384 number of display columns it is consuming to show the merge and its
385 parent commits, which has been corrected.
386 (merge 04005834ed np/log-graph-octopus-fix later to maint).
388 * "git range-diff" did not work well when the compared ranges had
389 changes in submodules and the "--submodule=log" was used.
391 * The implementation of run_command() API on the UNIX platforms had a
392 bug that caused a command not on $PATH to be found in the current
394 (merge f67b980771 jk/run-command-notdot later to maint).
396 * A mutex used in "git pack-objects" were not correctly initialized
397 and this caused "git repack" to dump core on Windows.
398 (merge 34204c8166 js/pack-objects-mutex-init-fix later to maint).
400 * Under certain circumstances, "git diff D:/a/b/c D:/a/b/d" on
401 Windows would strip initial parts from the paths because they
402 were not recognized as absolute, which has been corrected.
403 (merge ffd04e92e2 js/diff-notice-has-drive-prefix later to maint).
405 * The receive.denyCurrentBranch=updateInstead codepath kicked in even
406 when the push should have been rejected due to other reasons, such
407 as it does not fast-forward or the update-hook rejects it, which
409 (merge b072a25fad jc/receive-deny-current-branch-fix later to maint).
411 * The logic to determine the archive type "git archive" uses did not
412 correctly kick in for "git archive --remote", which has been
415 * "git repack" in a shallow clone did not correctly update the
416 shallow points in the repository, leading to a repository that
418 (merge 5dcfbf564c js/shallow-and-fetch-prune later to maint).
420 * Some codepaths failed to form a proper URL when .gitmodules record
421 the URL to a submodule repository as relative to the repository of
422 superproject, which has been corrected.
423 (merge e0a862fdaf sb/submodule-url-to-absolute later to maint).
425 * "git fetch" over protocol v2 into a shallow repository failed to
426 fetch full history behind a new tip of history that was diverged
427 before the cut-off point of the history that was previously fetched
430 * The command line completion machinery (in contrib/) has been
431 updated to allow the completion script to tweak the list of options
432 that are reported by the parse-options machinery correctly.
433 (merge 276b49ff34 nd/completion-negation later to maint).
435 * Operations on promisor objects make sense in the context of only a
436 small subset of the commands that internally use the revisions
437 machinery, but the "--exclude-promisor-objects" option were taken
438 and led to nonsense results by commands like "log", to which it
439 didn't make much sense. This has been corrected.
440 (merge 669b1d2aae md/exclude-promisor-objects-fix later to maint).
442 * The "container" mode of TravisCI is going away. Our .travis.yml
443 file is getting prepared for the transition.
444 (merge 32ee384be8 ss/travis-ci-force-vm-mode later to maint).
446 * Our test scripts can now take the '-V' option as a synonym for the
447 '--verbose-log' option.
448 (merge a5f52c6dab sg/test-verbose-log later to maint).
450 * Code cleanup, docfix, build fix, etc.
451 (merge 96a7501aad ts/doc-build-manpage-xsl-quietly later to maint).
452 (merge b9b07efdb2 tg/conflict-marker-size later to maint).
453 (merge fa0aeea770 sg/doc-trace-appends later to maint).
454 (merge d64324cb60 tb/void-check-attr later to maint).
455 (merge c3b9bc94b9 en/double-semicolon-fix later to maint).
456 (merge 79336116f5 sg/t3701-tighten-trace later to maint).
457 (merge 801fa63a90 jk/dev-build-format-security later to maint).
458 (merge 0597dd62ba sb/string-list-remove-unused later to maint).
459 (merge db2d36fad8 bw/protocol-v2 later to maint).
460 (merge 456d7cd3a9 sg/split-index-test later to maint).
461 (merge 7b6057c852 tq/refs-internal-comment-fix later to maint).
462 (merge 29e8dc50ad tg/t5551-with-curl-7.61.1 later to maint).
463 (merge 55f6bce2c9 fe/doc-updates later to maint).
464 (merge 7987d2232d jk/check-everything-connected-is-long-gone later to maint).
465 (merge 4ba3c9be47 dz/credential-doc-url-matching-rules later to maint).
466 (merge 4c399442f7 ma/commit-graph-docs later to maint).
467 (merge fc0503b04e ma/t1400-undebug-test later to maint).
468 (merge e56b53553a nd/packobjectshook-doc-fix later to maint).
469 (merge c56170a0c4 ma/mailing-list-address-in-git-help later to maint).
470 (merge 6e8fc70fce rs/sequencer-oidset-insert-avoids-dups later to maint).
471 (merge ad0b8f9575 mw/doc-typofixes later to maint).
472 (merge d9f079ad1a jc/how-to-document-api later to maint).
473 (merge b1492bf315 ma/t7005-bash-workaround later to maint).
474 (merge ac1f98a0df du/rev-parse-is-plumbing later to maint).
475 (merge ca8ed443a5 mm/doc-no-dashed-git later to maint).
476 (merge ce366a8144 du/get-tar-commit-id-is-plumbing later to maint).
477 (merge 61018fe9e0 du/cherry-is-plumbing later to maint).
478 (merge c7e5fe79b9 sb/strbuf-h-update later to maint).
479 (merge 8d2008196b tq/branch-create-wo-branch-get later to maint).
480 (merge 2e3c894f4b tq/branch-style-fix later to maint).
481 (merge c5d844af9c sg/doc-show-branch-typofix later to maint).
482 (merge 081d91618b ah/doc-updates later to maint).
483 (merge b84c783882 jc/cocci-preincr later to maint).
484 (merge 5e495f8122 uk/merge-subtree-doc-update later to maint).
485 (merge aaaa881822 jk/uploadpack-packobjectshook-fix later to maint).
486 (merge 3063477445 tb/char-may-be-unsigned later to maint).
487 (merge 8c64bc9420 sg/test-rebase-editor-fix later to maint).
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