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
30 UI, Workflows & Features
32 * Running "git clone" against a project that contain two files with
33 pathnames that differ only in cases on a case insensitive
34 filesystem would result in one of the files lost because the
35 underlying filesystem is incapable of holding both at the same
36 time. An attempt is made to detect such a case and warn.
38 * "git checkout -b newbranch [HEAD]" should not have to do as much as
39 checking out a commit different from HEAD. An attempt is made to
40 optimize this special case.
42 * "git rev-list --stdin </dev/null" used to be an error; it now shows
43 no output without an error. "git rev-list --stdin --default HEAD"
44 still falls back to the given default when nothing is given on the
47 * Lift code from GitHub to restrict delta computation so that an
48 object that exists in one fork is not made into a delta against
49 another object that does not appear in the same forked repository.
51 * "git format-patch" learned new "--interdiff" and "--range-diff"
52 options to explain the difference between this version and the
53 previous attempt in the cover letter (or after the tree-dashes as
56 * "git mailinfo" used in "git am" learned to make a best-effort
57 recovery of a patch corrupted by MUA that sends text/plain with
59 (merge 3aa4d81f88 rs/mailinfo-format-flowed later to maint).
61 * The rules used by "git push" and "git fetch" to determine if a ref
62 can or cannot be updated were inconsistent; specifically, fetching
63 to update existing tags were allowed even though tags are supposed
64 to be unmoving anchoring points. "git fetch" was taught to forbid
65 updates to existing tags without the "--force" option.
67 * "git multi-pack-index" learned to detect corruption in the .midx
68 file it uses, and this feature has been integrated into "git fsck".
70 * Generation of (experimental) commit-graph files have so far been
71 fairly silent, even though it takes noticeable amount of time in a
72 meaningfully large repository. The users will now see progress
75 * The minimum version of Windows supported by Windows port fo Git is
78 * The completion script (in contrib/) learned to complete a handful of
79 options "git stash list" command takes.
81 * The completion script (in contrib/) learned that "git fetch
82 --multiple" only takes remote names as arguments and no refspecs.
84 * "git status" learns to show progress bar when refreshing the index
86 (merge ae9af12287 nd/status-refresh-progress later to maint).
88 * "git help -a" and "git help -av" give different pieces of
89 information, and generally the "verbose" version is more friendly
90 to the new users. "git help -a" by default now uses the more
91 verbose output (with "--no-verbose", you can go back to the
92 original). Also "git help -av" now lists aliases and external
93 commands, which it did not used to.
95 * Unlike "grep", "git grep" by default recurses to the whole tree.
96 The command learned "git grep --recursive" option, so that "git
97 grep --no-recursive" can serve as a synonym to setting the
100 * When pushing into a repository that borrows its objects from an
101 alternate object store, "git receive-pack" that responds to the
102 push request on the other side lists the tips of refs in the
103 alternate to reduce the amount of objects transferred. This
104 sometimes is detrimental when the number of refs in the alternate
105 is absurdly large, in which case the bandwidth saved in potentially
106 fewer objects transferred is wasted in excessively large ref
107 advertisement. The alternate refs that are advertised are now
108 configurable with a pair of configuration variables.
110 * "git cmd --help" when "cmd" is aliased used to only say "cmd is
111 aliased to ...". Now it shows that to the standard error stream
112 and runs "git $cmd --help" where $cmd is the first word of the
115 * The documentation of "git gc" has been updated to mention that it
116 is no longer limited to "pruning away crufts" but also updates
117 ancillary files like commit-graph as a part of repository
120 * "git p4 unshelve" improvements.
122 * The logic to select the default user name and e-mail on Windows has
124 (merge 501afcb8b0 js/mingw-default-ident later to maint).
127 Performance, Internal Implementation, Development Support etc.
129 * When there are too many packfiles in a repository (which is not
130 recommended), looking up an object in these would require
131 consulting many pack .idx files; a new mechanism to have a single
132 file that consolidates all of these .idx files is introduced.
134 * "git submodule update" is getting rewritten piece-by-piece into C.
136 * The code for computing history reachability has been shuffled,
137 obtained a bunch of new tests to cover them, and then being
140 * The unpack_trees() API used in checking out a branch and merging
141 walks one or more trees along with the index. When the cache-tree
142 in the index tells us that we are walking a tree whose flattened
143 contents is known (i.e. matches a span in the index), as linearly
144 scanning a span in the index is much more efficient than having to
145 open tree objects recursively and listing their entries, the walk
146 can be optimized, which has been done.
148 * When creating a thin pack, which allows objects to be made into a
149 delta against another object that is not in the resulting pack but
150 is known to be present on the receiving end, the code learned to
151 take advantage of the reachability bitmap; this allows the server
152 to send a delta against a base beyond the "boundary" commit.
154 * spatch transformation to replace boolean uses of !hashcmp() to
155 newly introduced oideq() is added, and applied, to regain
156 performance lost due to support of multiple hash algorithms.
158 * Fix a bug in which the same path could be registered under multiple
159 worktree entries if the path was missing (for instance, was removed
160 manually). Also, as a convenience, expand the number of cases in
161 which --force is applicable.
163 * Split Documentation/config.txt for easier maintenance.
164 (merge 6014363f0b nd/config-split later to maint).
166 * Test helper binaries clean-up.
167 (merge c9a1f4161f nd/test-tool later to maint).
169 * Various tests have been updated to make it easier to swap the
170 hash function used for object identification.
171 (merge ae0c89d41b bc/hash-independent-tests later to maint).
173 * Update fsck.skipList implementation and documentation.
174 (merge 371a655074 ab/fsck-skiplist later to maint).
176 * An alias that expands to another alias has so far been forbidden,
177 but now it is allowed to create such an alias.
179 * Various test scripts have been updated for style and also correct
180 handling of exit status of various commands.
182 * "gc --auto" ended up calling exit(-1) upon error, which has been
183 corrected to use exit(1). Also the error reporting behaviour when
184 daemonized has been updated to exit with zero status when stopping
185 due to a previously discovered error (which implies there is no
186 point running gc to improve the situation); we used to exit with
187 failure in such a case.
189 * Various codepaths in the core-ish part learned to work on an
190 arbitrary in-core index structure, not necessarily the default
191 instance "the_index".
192 (merge b3c7eef9b0 nd/the-index later to maint).
194 * Code clean-up in the internal machinery used by "git status" and
195 "git commit --dry-run".
196 (merge 73ba5d78b4 ss/wt-status-committable later to maint).
198 * Some environment variables that control the runtime options of Git
199 used during tests are getting renamed for consistency.
200 (merge 4231d1ba99 bp/rename-test-env-var later to maint).
202 * A new extension to the index file has been introduced, which allows
203 the index file to be read in parallel for performance.
205 * The oidset API was built on top of the oidmap API which in turn is
206 on the hashmap API. Replace the implementation to build on top of
207 the khash API and gain performance.
209 * Over some transports, fetching objects with an exact commit object
210 name can be done without first seeing the ref advertisements. The
211 code has been optimized to exploit this.
213 * In a partial clone that will lazily be hydrated from the
214 originating repository, we generally want to avoid "does this
215 object exist (locally)?" on objects that we deliberately omitted
216 when we created the clone. The cache-tree codepath (which is used
217 to write a tree object out of the index) however insisted that the
218 object exists, even for paths that are outside of the partial
219 checkout area. The code has been updated to avoid such a check.
221 * To help developers, an EditorConfig file that attempts to follow
222 the project convention has been added.
223 (merge b548d698a0 bc/editorconfig later to maint).
225 * The result of coverage test can be combined with "git blame" to
226 check the test coverage of code introduced recently with a new
227 'coverage-diff' tool (in contrib/).
228 (merge 783faedd65 ds/coverage-diff later to maint).
230 * An experiment to fuzz test a few areas, hopefully we can gain more
231 coverage to various areas.
237 * "git interpret-trailers" and its underlying machinery had a buggy
238 code that attempted to ignore patch text after commit log message,
239 which triggered in various codepaths that will always get the log
240 message alone and never get such an input.
241 (merge 66e83d9b41 jk/trailer-fixes later to maint).
243 * Malformed or crafted data in packstream can make our code attempt
244 to read or write past the allocated buffer and abort, instead of
245 reporting an error, which has been fixed.
247 * "git rebase -i" did not clear the state files correctly when a run
248 of "squash/fixup" is aborted and then the user manually amended the
249 commit instead, which has been corrected.
250 (merge 10d2f35436 js/rebase-i-autosquash-fix later to maint).
252 * When fsmonitor is in use, after operation on submodules updates
253 .gitmodules, we lost track of the fact that we did so and relied on
254 stale fsmonitor data.
255 (merge 43f1180814 bp/mv-submodules-with-fsmonitor later to maint).
257 * Fix for a long-standing bug that leaves the index file corrupt when
258 it shrinks during a partial commit.
259 (merge 6c003d6ffb jk/reopen-tempfile-truncate later to maint).
261 * Further fix for O_APPEND emulation on Windows
262 (merge eeaf7ddac7 js/mingw-o-append later to maint).
264 * A corner case bugfix in "git rerere" code.
265 (merge ad2bf0d9b4 en/rerere-multi-stage-1-fix later to maint).
267 * "git add ':(attr:foo)'" is not supported and is supposed to be
268 rejected while the command line arguments are parsed, but we fail
269 to reject such a command line upfront.
270 (merge 84d938b732 nd/attr-pathspec-fix later to maint).
272 * Recent update broke the reachability algorithm when refs (e.g.
273 tags) that point at objects that are not commit were involved,
274 which has been fixed.
276 * "git rebase" etc. in Git 2.19 fails to abort when given an empty
277 commit log message as result of editing, which has been corrected.
278 (merge a3ec9eaf38 en/sequencer-empty-edit-result-aborts later to maint).
280 * The code to backfill objects in lazily cloned repository did not
281 work correctly, which has been corrected.
282 (merge e68302011c jt/lazy-object-fetch-fix later to maint).
284 * Update error messages given by "git remote" and make them consistent.
285 (merge 5025425dff ms/remote-error-message-update later to maint).
287 * "git update-ref" learned to make both "--no-deref" and "--stdin"
288 work at the same time.
289 (merge d345e9fbe7 en/update-ref-no-deref-stdin later to maint).
291 * Recently added "range-diff" had a corner-case bug to cause it
292 segfault, which has been corrected.
293 (merge e467a90c7a tg/range-diff-corner-case-fix later to maint).
295 * The recently introduced commit-graph auxiliary data is incompatible
296 with mechanisms such as replace & grafts that "breaks" immutable
297 nature of the object reference relationship. Disable optimizations
298 based on its use (and updating existing commit-graph) when these
299 incompatible features are in use in the repository.
300 (merge 829a321569 ds/commit-graph-with-grafts later to maint).
302 * The mailmap file update.
303 (merge 255eb03edf jn/mailmap-update later to maint).
305 * The code in "git status" sometimes hit an assertion failure. This
306 was caused by a structure that was reused without cleaning the data
307 used for the first run, which has been corrected.
308 (merge 3e73cc62c0 en/status-multiple-renames-to-the-same-target-fix later to maint).
310 * "git fetch $repo $object" in a partial clone did not correctly
311 fetch the asked-for object that is referenced by an object in
312 promisor packfile, which has been fixed.
314 * A corner-case bugfix.
315 (merge c5cbb27cb5 sm/show-superproject-while-conflicted later to maint).
317 * Various fixes to "diff --color-moved-ws".
319 * A partial clone that is configured to lazily fetch missing objects
320 will on-demand issue a "git fetch" request to the originating
321 repository to fill not-yet-obtained objects. The request has been
322 optimized for requesting a tree object (and not the leaf blob
323 objects contained in it) by telling the originating repository that
325 (merge 4c7f9567ea jt/non-blob-lazy-fetch later to maint).
327 * The codepath to support the experimental split-index mode had
328 remaining "racily clean" issues fixed.
329 (merge 4c490f3d32 sg/split-index-racefix later to maint).
331 * "git log --graph" showing an octopus merge sometimes miscounted the
332 number of display columns it is consuming to show the merge and its
333 parent commits, which has been corrected.
334 (merge 04005834ed np/log-graph-octopus-fix later to maint).
336 * Code cleanup, docfix, build fix, etc.
337 (merge 96a7501aad ts/doc-build-manpage-xsl-quietly later to maint).
338 (merge b9b07efdb2 tg/conflict-marker-size later to maint).
339 (merge fa0aeea770 sg/doc-trace-appends later to maint).
340 (merge d64324cb60 tb/void-check-attr later to maint).
341 (merge c3b9bc94b9 en/double-semicolon-fix later to maint).
342 (merge 79336116f5 sg/t3701-tighten-trace later to maint).
343 (merge 801fa63a90 jk/dev-build-format-security later to maint).
344 (merge 0597dd62ba sb/string-list-remove-unused later to maint).
345 (merge db2d36fad8 bw/protocol-v2 later to maint).
346 (merge 456d7cd3a9 sg/split-index-test later to maint).
347 (merge 7b6057c852 tq/refs-internal-comment-fix later to maint).
348 (merge 29e8dc50ad tg/t5551-with-curl-7.61.1 later to maint).
349 (merge 55f6bce2c9 fe/doc-updates later to maint).
350 (merge 7987d2232d jk/check-everything-connected-is-long-gone later to maint).
351 (merge 4ba3c9be47 dz/credential-doc-url-matching-rules later to maint).
352 (merge 4c399442f7 ma/commit-graph-docs later to maint).
353 (merge fc0503b04e ma/t1400-undebug-test later to maint).
354 (merge e56b53553a nd/packobjectshook-doc-fix later to maint).
355 (merge c56170a0c4 ma/mailing-list-address-in-git-help later to maint).
356 (merge 6e8fc70fce rs/sequencer-oidset-insert-avoids-dups later to maint).
357 (merge ad0b8f9575 mw/doc-typofixes later to maint).
358 (merge d9f079ad1a jc/how-to-document-api later to maint).
359 (merge b1492bf315 ma/t7005-bash-workaround later to maint).
360 (merge ac1f98a0df du/rev-parse-is-plumbing later to maint).
361 (merge ca8ed443a5 mm/doc-no-dashed-git later to maint).
362 (merge ce366a8144 du/get-tar-commit-id-is-plumbing later to maint).
363 (merge 61018fe9e0 du/cherry-is-plumbing later to maint).