Merge branch 'en/filter-branch-deprecation'
[git/git.git] / Documentation / githooks.txt
1 githooks(5)
2 ===========
3
4 NAME
5 ----
6 githooks - Hooks used by Git
7
8 SYNOPSIS
9 --------
10 $GIT_DIR/hooks/* (or \`git config core.hooksPath`/*)
11
12
13 DESCRIPTION
14 -----------
15
16 Hooks are programs you can place in a hooks directory to trigger
17 actions at certain points in git's execution. Hooks that don't have
18 the executable bit set are ignored.
19
20 By default the hooks directory is `$GIT_DIR/hooks`, but that can be
21 changed via the `core.hooksPath` configuration variable (see
22 linkgit:git-config[1]).
23
24 Before Git invokes a hook, it changes its working directory to either
25 $GIT_DIR in a bare repository or the root of the working tree in a non-bare
26 repository. An exception are hooks triggered during a push ('pre-receive',
27 'update', 'post-receive', 'post-update', 'push-to-checkout') which are always
28 executed in $GIT_DIR.
29
30 Hooks can get their arguments via the environment, command-line
31 arguments, and stdin. See the documentation for each hook below for
32 details.
33
34 `git init` may copy hooks to the new repository, depending on its
35 configuration. See the "TEMPLATE DIRECTORY" section in
36 linkgit:git-init[1] for details. When the rest of this document refers
37 to "default hooks" it's talking about the default template shipped
38 with Git.
39
40 The currently supported hooks are described below.
41
42 HOOKS
43 -----
44
45 applypatch-msg
46 ~~~~~~~~~~~~~~
47
48 This hook is invoked by linkgit:git-am[1]. It takes a single
49 parameter, the name of the file that holds the proposed commit
50 log message. Exiting with a non-zero status causes `git am` to abort
51 before applying the patch.
52
53 The hook is allowed to edit the message file in place, and can
54 be used to normalize the message into some project standard
55 format. It can also be used to refuse the commit after inspecting
56 the message file.
57
58 The default 'applypatch-msg' hook, when enabled, runs the
59 'commit-msg' hook, if the latter is enabled.
60
61 pre-applypatch
62 ~~~~~~~~~~~~~~
63
64 This hook is invoked by linkgit:git-am[1]. It takes no parameter, and is
65 invoked after the patch is applied, but before a commit is made.
66
67 If it exits with non-zero status, then the working tree will not be
68 committed after applying the patch.
69
70 It can be used to inspect the current working tree and refuse to
71 make a commit if it does not pass certain test.
72
73 The default 'pre-applypatch' hook, when enabled, runs the
74 'pre-commit' hook, if the latter is enabled.
75
76 post-applypatch
77 ~~~~~~~~~~~~~~~
78
79 This hook is invoked by linkgit:git-am[1]. It takes no parameter,
80 and is invoked after the patch is applied and a commit is made.
81
82 This hook is meant primarily for notification, and cannot affect
83 the outcome of `git am`.
84
85 pre-commit
86 ~~~~~~~~~~
87
88 This hook is invoked by linkgit:git-commit[1], and can be bypassed
89 with the `--no-verify` option. It takes no parameters, and is
90 invoked before obtaining the proposed commit log message and
91 making a commit. Exiting with a non-zero status from this script
92 causes the `git commit` command to abort before creating a commit.
93
94 The default 'pre-commit' hook, when enabled, catches introduction
95 of lines with trailing whitespaces and aborts the commit when
96 such a line is found.
97
98 All the `git commit` hooks are invoked with the environment
99 variable `GIT_EDITOR=:` if the command will not bring up an editor
100 to modify the commit message.
101
102 The default 'pre-commit' hook, when enabled--and with the
103 `hooks.allownonascii` config option unset or set to false--prevents
104 the use of non-ASCII filenames.
105
106 pre-merge-commit
107 ~~~~~~~~~~~~~~~~
108
109 This hook is invoked by linkgit:git-merge[1], and can be bypassed
110 with the `--no-verify` option. It takes no parameters, and is
111 invoked after the merge has been carried out successfully and before
112 obtaining the proposed commit log message to
113 make a commit. Exiting with a non-zero status from this script
114 causes the `git merge` command to abort before creating a commit.
115
116 The default 'pre-merge-commit' hook, when enabled, runs the
117 'pre-commit' hook, if the latter is enabled.
118
119 This hook is invoked with the environment variable
120 `GIT_EDITOR=:` if the command will not bring up an editor
121 to modify the commit message.
122
123 If the merge cannot be carried out automatically, the conflicts
124 need to be resolved and the result committed separately (see
125 linkgit:git-merge[1]). At that point, this hook will not be executed,
126 but the 'pre-commit' hook will, if it is enabled.
127
128 prepare-commit-msg
129 ~~~~~~~~~~~~~~~~~~
130
131 This hook is invoked by linkgit:git-commit[1] right after preparing the
132 default log message, and before the editor is started.
133
134 It takes one to three parameters. The first is the name of the file
135 that contains the commit log message. The second is the source of the commit
136 message, and can be: `message` (if a `-m` or `-F` option was
137 given); `template` (if a `-t` option was given or the
138 configuration option `commit.template` is set); `merge` (if the
139 commit is a merge or a `.git/MERGE_MSG` file exists); `squash`
140 (if a `.git/SQUASH_MSG` file exists); or `commit`, followed by
141 a commit SHA-1 (if a `-c`, `-C` or `--amend` option was given).
142
143 If the exit status is non-zero, `git commit` will abort.
144
145 The purpose of the hook is to edit the message file in place, and
146 it is not suppressed by the `--no-verify` option. A non-zero exit
147 means a failure of the hook and aborts the commit. It should not
148 be used as replacement for pre-commit hook.
149
150 The sample `prepare-commit-msg` hook that comes with Git removes the
151 help message found in the commented portion of the commit template.
152
153 commit-msg
154 ~~~~~~~~~~
155
156 This hook is invoked by linkgit:git-commit[1] and linkgit:git-merge[1], and can be
157 bypassed with the `--no-verify` option. It takes a single parameter,
158 the name of the file that holds the proposed commit log message.
159 Exiting with a non-zero status causes the command to abort.
160
161 The hook is allowed to edit the message file in place, and can be used
162 to normalize the message into some project standard format. It
163 can also be used to refuse the commit after inspecting the message
164 file.
165
166 The default 'commit-msg' hook, when enabled, detects duplicate
167 "Signed-off-by" lines, and aborts the commit if one is found.
168
169 post-commit
170 ~~~~~~~~~~~
171
172 This hook is invoked by linkgit:git-commit[1]. It takes no parameters, and is
173 invoked after a commit is made.
174
175 This hook is meant primarily for notification, and cannot affect
176 the outcome of `git commit`.
177
178 pre-rebase
179 ~~~~~~~~~~
180
181 This hook is called by linkgit:git-rebase[1] and can be used to prevent a
182 branch from getting rebased. The hook may be called with one or
183 two parameters. The first parameter is the upstream from which
184 the series was forked. The second parameter is the branch being
185 rebased, and is not set when rebasing the current branch.
186
187 post-checkout
188 ~~~~~~~~~~~~~
189
190 This hook is invoked when a linkgit:git-checkout[1] or
191 linkgit:git-switch[1] is run after having updated the
192 worktree. The hook is given three parameters: the ref of the previous HEAD,
193 the ref of the new HEAD (which may or may not have changed), and a flag
194 indicating whether the checkout was a branch checkout (changing branches,
195 flag=1) or a file checkout (retrieving a file from the index, flag=0).
196 This hook cannot affect the outcome of `git switch` or `git checkout`.
197
198 It is also run after linkgit:git-clone[1], unless the `--no-checkout` (`-n`) option is
199 used. The first parameter given to the hook is the null-ref, the second the
200 ref of the new HEAD and the flag is always 1. Likewise for `git worktree add`
201 unless `--no-checkout` is used.
202
203 This hook can be used to perform repository validity checks, auto-display
204 differences from the previous HEAD if different, or set working dir metadata
205 properties.
206
207 post-merge
208 ~~~~~~~~~~
209
210 This hook is invoked by linkgit:git-merge[1], which happens when a `git pull`
211 is done on a local repository. The hook takes a single parameter, a status
212 flag specifying whether or not the merge being done was a squash merge.
213 This hook cannot affect the outcome of `git merge` and is not executed,
214 if the merge failed due to conflicts.
215
216 This hook can be used in conjunction with a corresponding pre-commit hook to
217 save and restore any form of metadata associated with the working tree
218 (e.g.: permissions/ownership, ACLS, etc). See contrib/hooks/setgitperms.perl
219 for an example of how to do this.
220
221 pre-push
222 ~~~~~~~~
223
224 This hook is called by linkgit:git-push[1] and can be used to prevent
225 a push from taking place. The hook is called with two parameters
226 which provide the name and location of the destination remote, if a
227 named remote is not being used both values will be the same.
228
229 Information about what is to be pushed is provided on the hook's standard
230 input with lines of the form:
231
232 <local ref> SP <local sha1> SP <remote ref> SP <remote sha1> LF
233
234 For instance, if the command +git push origin master:foreign+ were run the
235 hook would receive a line like the following:
236
237 refs/heads/master 67890 refs/heads/foreign 12345
238
239 although the full, 40-character SHA-1s would be supplied. If the foreign ref
240 does not yet exist the `<remote SHA-1>` will be 40 `0`. If a ref is to be
241 deleted, the `<local ref>` will be supplied as `(delete)` and the `<local
242 SHA-1>` will be 40 `0`. If the local commit was specified by something other
243 than a name which could be expanded (such as `HEAD~`, or a SHA-1) it will be
244 supplied as it was originally given.
245
246 If this hook exits with a non-zero status, `git push` will abort without
247 pushing anything. Information about why the push is rejected may be sent
248 to the user by writing to standard error.
249
250 [[pre-receive]]
251 pre-receive
252 ~~~~~~~~~~~
253
254 This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
255 `git push` and updates reference(s) in its repository.
256 Just before starting to update refs on the remote repository, the
257 pre-receive hook is invoked. Its exit status determines the success
258 or failure of the update.
259
260 This hook executes once for the receive operation. It takes no
261 arguments, but for each ref to be updated it receives on standard
262 input a line of the format:
263
264 <old-value> SP <new-value> SP <ref-name> LF
265
266 where `<old-value>` is the old object name stored in the ref,
267 `<new-value>` is the new object name to be stored in the ref and
268 `<ref-name>` is the full name of the ref.
269 When creating a new ref, `<old-value>` is 40 `0`.
270
271 If the hook exits with non-zero status, none of the refs will be
272 updated. If the hook exits with zero, updating of individual refs can
273 still be prevented by the <<update,'update'>> hook.
274
275 Both standard output and standard error output are forwarded to
276 `git send-pack` on the other end, so you can simply `echo` messages
277 for the user.
278
279 The number of push options given on the command line of
280 `git push --push-option=...` can be read from the environment
281 variable `GIT_PUSH_OPTION_COUNT`, and the options themselves are
282 found in `GIT_PUSH_OPTION_0`, `GIT_PUSH_OPTION_1`,...
283 If it is negotiated to not use the push options phase, the
284 environment variables will not be set. If the client selects
285 to use push options, but doesn't transmit any, the count variable
286 will be set to zero, `GIT_PUSH_OPTION_COUNT=0`.
287
288 See the section on "Quarantine Environment" in
289 linkgit:git-receive-pack[1] for some caveats.
290
291 [[update]]
292 update
293 ~~~~~~
294
295 This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
296 `git push` and updates reference(s) in its repository.
297 Just before updating the ref on the remote repository, the update hook
298 is invoked. Its exit status determines the success or failure of
299 the ref update.
300
301 The hook executes once for each ref to be updated, and takes
302 three parameters:
303
304 - the name of the ref being updated,
305 - the old object name stored in the ref,
306 - and the new object name to be stored in the ref.
307
308 A zero exit from the update hook allows the ref to be updated.
309 Exiting with a non-zero status prevents `git receive-pack`
310 from updating that ref.
311
312 This hook can be used to prevent 'forced' update on certain refs by
313 making sure that the object name is a commit object that is a
314 descendant of the commit object named by the old object name.
315 That is, to enforce a "fast-forward only" policy.
316
317 It could also be used to log the old..new status. However, it
318 does not know the entire set of branches, so it would end up
319 firing one e-mail per ref when used naively, though. The
320 <<post-receive,'post-receive'>> hook is more suited to that.
321
322 In an environment that restricts the users' access only to git
323 commands over the wire, this hook can be used to implement access
324 control without relying on filesystem ownership and group
325 membership. See linkgit:git-shell[1] for how you might use the login
326 shell to restrict the user's access to only git commands.
327
328 Both standard output and standard error output are forwarded to
329 `git send-pack` on the other end, so you can simply `echo` messages
330 for the user.
331
332 The default 'update' hook, when enabled--and with
333 `hooks.allowunannotated` config option unset or set to false--prevents
334 unannotated tags to be pushed.
335
336 [[post-receive]]
337 post-receive
338 ~~~~~~~~~~~~
339
340 This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
341 `git push` and updates reference(s) in its repository.
342 It executes on the remote repository once after all the refs have
343 been updated.
344
345 This hook executes once for the receive operation. It takes no
346 arguments, but gets the same information as the
347 <<pre-receive,'pre-receive'>>
348 hook does on its standard input.
349
350 This hook does not affect the outcome of `git receive-pack`, as it
351 is called after the real work is done.
352
353 This supersedes the <<post-update,'post-update'>> hook in that it gets
354 both old and new values of all the refs in addition to their
355 names.
356
357 Both standard output and standard error output are forwarded to
358 `git send-pack` on the other end, so you can simply `echo` messages
359 for the user.
360
361 The default 'post-receive' hook is empty, but there is
362 a sample script `post-receive-email` provided in the `contrib/hooks`
363 directory in Git distribution, which implements sending commit
364 emails.
365
366 The number of push options given on the command line of
367 `git push --push-option=...` can be read from the environment
368 variable `GIT_PUSH_OPTION_COUNT`, and the options themselves are
369 found in `GIT_PUSH_OPTION_0`, `GIT_PUSH_OPTION_1`,...
370 If it is negotiated to not use the push options phase, the
371 environment variables will not be set. If the client selects
372 to use push options, but doesn't transmit any, the count variable
373 will be set to zero, `GIT_PUSH_OPTION_COUNT=0`.
374
375 [[post-update]]
376 post-update
377 ~~~~~~~~~~~
378
379 This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
380 `git push` and updates reference(s) in its repository.
381 It executes on the remote repository once after all the refs have
382 been updated.
383
384 It takes a variable number of parameters, each of which is the
385 name of ref that was actually updated.
386
387 This hook is meant primarily for notification, and cannot affect
388 the outcome of `git receive-pack`.
389
390 The 'post-update' hook can tell what are the heads that were pushed,
391 but it does not know what their original and updated values are,
392 so it is a poor place to do log old..new. The
393 <<post-receive,'post-receive'>> hook does get both original and
394 updated values of the refs. You might consider it instead if you need
395 them.
396
397 When enabled, the default 'post-update' hook runs
398 `git update-server-info` to keep the information used by dumb
399 transports (e.g., HTTP) up to date. If you are publishing
400 a Git repository that is accessible via HTTP, you should
401 probably enable this hook.
402
403 Both standard output and standard error output are forwarded to
404 `git send-pack` on the other end, so you can simply `echo` messages
405 for the user.
406
407 push-to-checkout
408 ~~~~~~~~~~~~~~~~
409
410 This hook is invoked by linkgit:git-receive-pack[1] when it reacts to
411 `git push` and updates reference(s) in its repository, and when
412 the push tries to update the branch that is currently checked out
413 and the `receive.denyCurrentBranch` configuration variable is set to
414 `updateInstead`. Such a push by default is refused if the working
415 tree and the index of the remote repository has any difference from
416 the currently checked out commit; when both the working tree and the
417 index match the current commit, they are updated to match the newly
418 pushed tip of the branch. This hook is to be used to override the
419 default behaviour.
420
421 The hook receives the commit with which the tip of the current
422 branch is going to be updated. It can exit with a non-zero status
423 to refuse the push (when it does so, it must not modify the index or
424 the working tree). Or it can make any necessary changes to the
425 working tree and to the index to bring them to the desired state
426 when the tip of the current branch is updated to the new commit, and
427 exit with a zero status.
428
429 For example, the hook can simply run `git read-tree -u -m HEAD "$1"`
430 in order to emulate `git fetch` that is run in the reverse direction
431 with `git push`, as the two-tree form of `git read-tree -u -m` is
432 essentially the same as `git switch` or `git checkout`
433 that switches branches while
434 keeping the local changes in the working tree that do not interfere
435 with the difference between the branches.
436
437
438 pre-auto-gc
439 ~~~~~~~~~~~
440
441 This hook is invoked by `git gc --auto` (see linkgit:git-gc[1]). It
442 takes no parameter, and exiting with non-zero status from this script
443 causes the `git gc --auto` to abort.
444
445 post-rewrite
446 ~~~~~~~~~~~~
447
448 This hook is invoked by commands that rewrite commits
449 (linkgit:git-commit[1] when called with `--amend` and
450 linkgit:git-rebase[1]; however, full-history (re)writing tools like
451 linkgit:git-fast-import[1] or
452 https://github.com/newren/git-filter-repo[git-filter-repo] typically
453 do not call it!). Its first argument denotes the command it was
454 invoked by: currently one of `amend` or `rebase`. Further
455 command-dependent arguments may be passed in the future.
456
457 The hook receives a list of the rewritten commits on stdin, in the
458 format
459
460 <old-sha1> SP <new-sha1> [ SP <extra-info> ] LF
461
462 The 'extra-info' is again command-dependent. If it is empty, the
463 preceding SP is also omitted. Currently, no commands pass any
464 'extra-info'.
465
466 The hook always runs after the automatic note copying (see
467 "notes.rewrite.<command>" in linkgit:git-config[1]) has happened, and
468 thus has access to these notes.
469
470 The following command-specific comments apply:
471
472 rebase::
473 For the 'squash' and 'fixup' operation, all commits that were
474 squashed are listed as being rewritten to the squashed commit.
475 This means that there will be several lines sharing the same
476 'new-sha1'.
477 +
478 The commits are guaranteed to be listed in the order that they were
479 processed by rebase.
480
481 sendemail-validate
482 ~~~~~~~~~~~~~~~~~~
483
484 This hook is invoked by linkgit:git-send-email[1]. It takes a single parameter,
485 the name of the file that holds the e-mail to be sent. Exiting with a
486 non-zero status causes `git send-email` to abort before sending any
487 e-mails.
488
489 fsmonitor-watchman
490 ~~~~~~~~~~~~~~~~~~
491
492 This hook is invoked when the configuration option `core.fsmonitor` is
493 set to `.git/hooks/fsmonitor-watchman`. It takes two arguments, a version
494 (currently 1) and the time in elapsed nanoseconds since midnight,
495 January 1, 1970.
496
497 The hook should output to stdout the list of all files in the working
498 directory that may have changed since the requested time. The logic
499 should be inclusive so that it does not miss any potential changes.
500 The paths should be relative to the root of the working directory
501 and be separated by a single NUL.
502
503 It is OK to include files which have not actually changed. All changes
504 including newly-created and deleted files should be included. When
505 files are renamed, both the old and the new name should be included.
506
507 Git will limit what files it checks for changes as well as which
508 directories are checked for untracked files based on the path names
509 given.
510
511 An optimized way to tell git "all files have changed" is to return
512 the filename `/`.
513
514 The exit status determines whether git will use the data from the
515 hook to limit its search. On error, it will fall back to verifying
516 all files and folders.
517
518 p4-pre-submit
519 ~~~~~~~~~~~~~
520
521 This hook is invoked by `git-p4 submit`. It takes no parameters and nothing
522 from standard input. Exiting with non-zero status from this script prevent
523 `git-p4 submit` from launching. Run `git-p4 submit --help` for details.
524
525 post-index-change
526 ~~~~~~~~~~~~~~~~~
527
528 This hook is invoked when the index is written in read-cache.c
529 do_write_locked_index.
530
531 The first parameter passed to the hook is the indicator for the
532 working directory being updated. "1" meaning working directory
533 was updated or "0" when the working directory was not updated.
534
535 The second parameter passed to the hook is the indicator for whether
536 or not the index was updated and the skip-worktree bit could have
537 changed. "1" meaning skip-worktree bits could have been updated
538 and "0" meaning they were not.
539
540 Only one parameter should be set to "1" when the hook runs. The hook
541 running passing "1", "1" should not be possible.
542
543 GIT
544 ---
545 Part of the linkgit:git[1] suite