Third batch of topics for 2.10
[git/git.git] / Documentation / githooks.txt
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1githooks(5)
2===========
3
4NAME
5----
2de9b711 6githooks - Hooks used by Git
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7
8SYNOPSIS
9--------
867ad08a 10$GIT_DIR/hooks/* (or \`git config core.hooksPath`/*)
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11
12
13DESCRIPTION
14-----------
6d35cc76 15
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16Hooks are programs you can place in a hooks directory to trigger
17actions at certain points in git's execution. Hooks that don't have
18the executable bit set are ignored.
19
20By default the hooks directory is `$GIT_DIR/hooks`, but that can be
21changed via the `core.hooksPath` configuration variable (see
22linkgit:git-config[1]).
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23
24Before Git invokes a hook, it changes its working directory to either
25the root of the working tree in a non-bare repository, or to the
26$GIT_DIR in a bare repository.
27
28Hooks can get their arguments via the environment, command-line
29arguments, and stdin. See the documentation for each hook below for
30details.
31
32'git init' may copy hooks to the new repository, depending on its
33configuration. See the "TEMPLATE DIRECTORY" section in
34linkgit:git-init[1] for details. When the rest of this document refers
35to "default hooks" it's talking about the default template shipped
36with Git.
37
38The currently supported hooks are described below.
6d35cc76 39
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40HOOKS
41-----
42
6d35cc76 43applypatch-msg
6d71c1dc 44~~~~~~~~~~~~~~
6d35cc76 45
de0824ed 46This hook is invoked by 'git am'. It takes a single
6d35cc76 47parameter, the name of the file that holds the proposed commit
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48log message. Exiting with a non-zero status causes 'git am' to abort
49before applying the patch.
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50
51The hook is allowed to edit the message file in place, and can
52be used to normalize the message into some project standard
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53format. It can also be used to refuse the commit after inspecting
54the message file.
6d35cc76 55
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56The default 'applypatch-msg' hook, when enabled, runs the
57'commit-msg' hook, if the latter is enabled.
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58
59pre-applypatch
6d71c1dc 60~~~~~~~~~~~~~~
6d35cc76 61
0b444cdb 62This hook is invoked by 'git am'. It takes no parameter, and is
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63invoked after the patch is applied, but before a commit is made.
64
65If it exits with non-zero status, then the working tree will not be
66committed after applying the patch.
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67
68It can be used to inspect the current working tree and refuse to
69make a commit if it does not pass certain test.
70
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71The default 'pre-applypatch' hook, when enabled, runs the
72'pre-commit' hook, if the latter is enabled.
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73
74post-applypatch
6d71c1dc 75~~~~~~~~~~~~~~~
6d35cc76 76
0b444cdb 77This hook is invoked by 'git am'. It takes no parameter,
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78and is invoked after the patch is applied and a commit is made.
79
80This hook is meant primarily for notification, and cannot affect
0b444cdb 81the outcome of 'git am'.
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82
83pre-commit
6d71c1dc 84~~~~~~~~~~
6d35cc76 85
0b444cdb 86This hook is invoked by 'git commit', and can be bypassed
de0824ed 87with the `--no-verify` option. It takes no parameters, and is
6d35cc76 88invoked before obtaining the proposed commit log message and
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89making a commit. Exiting with a non-zero status from this script
90causes the 'git commit' command to abort before creating a commit.
6d35cc76 91
45ad9b50 92The default 'pre-commit' hook, when enabled, catches introduction
6d35cc76 93of lines with trailing whitespaces and aborts the commit when
45ad9b50 94such a line is found.
6d35cc76 95
0b444cdb 96All the 'git commit' hooks are invoked with the environment
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97variable `GIT_EDITOR=:` if the command will not bring up an editor
98to modify the commit message.
99
8089c85b 100prepare-commit-msg
6d71c1dc 101~~~~~~~~~~~~~~~~~~
8089c85b 102
0b444cdb 103This hook is invoked by 'git commit' right after preparing the
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104default log message, and before the editor is started.
105
106It takes one to three parameters. The first is the name of the file
99686960 107that contains the commit log message. The second is the source of the commit
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108message, and can be: `message` (if a `-m` or `-F` option was
109given); `template` (if a `-t` option was given or the
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110configuration option `commit.template` is set); `merge` (if the
111commit is a merge or a `.git/MERGE_MSG` file exists); `squash`
112(if a `.git/SQUASH_MSG` file exists); or `commit`, followed by
d5fa1f1a 113a commit SHA-1 (if a `-c`, `-C` or `--amend` option was given).
8089c85b 114
0b444cdb 115If the exit status is non-zero, 'git commit' will abort.
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116
117The purpose of the hook is to edit the message file in place, and
6cf378f0 118it is not suppressed by the `--no-verify` option. A non-zero exit
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119means a failure of the hook and aborts the commit. It should not
120be used as replacement for pre-commit hook.
121
2de9b711 122The sample `prepare-commit-msg` hook that comes with Git comments
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123out the `Conflicts:` part of a merge's commit message.
124
6d35cc76 125commit-msg
6d71c1dc 126~~~~~~~~~~
6d35cc76 127
0b444cdb 128This hook is invoked by 'git commit', and can be bypassed
de0824ed 129with the `--no-verify` option. It takes a single parameter, the
6d35cc76 130name of the file that holds the proposed commit log message.
de0824ed 131Exiting with a non-zero status causes the 'git commit' to
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132abort.
133
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134The hook is allowed to edit the message file in place, and can be used
135to normalize the message into some project standard format. It
136can also be used to refuse the commit after inspecting the message
137file.
6d35cc76 138
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139The default 'commit-msg' hook, when enabled, detects duplicate
140"Signed-off-by" lines, and aborts the commit if one is found.
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141
142post-commit
6d71c1dc 143~~~~~~~~~~~
6d35cc76 144
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145This hook is invoked by 'git commit'. It takes no parameters, and is
146invoked after a commit is made.
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147
148This hook is meant primarily for notification, and cannot affect
0b444cdb 149the outcome of 'git commit'.
6d35cc76 150
00e5d48a 151pre-rebase
6d71c1dc 152~~~~~~~~~~
00e5d48a 153
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154This hook is called by 'git rebase' and can be used to prevent a
155branch from getting rebased. The hook may be called with one or
156two parameters. The first parameter is the upstream from which
157the series was forked. The second parameter is the branch being
158rebased, and is not set when rebasing the current branch.
00e5d48a 159
1abbe475 160post-checkout
6d71c1dc 161~~~~~~~~~~~~~
1abbe475 162
0b444cdb 163This hook is invoked when a 'git checkout' is run after having updated the
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164worktree. The hook is given three parameters: the ref of the previous HEAD,
165the ref of the new HEAD (which may or may not have changed), and a flag
166indicating whether the checkout was a branch checkout (changing branches,
167flag=1) or a file checkout (retrieving a file from the index, flag=0).
0b444cdb 168This hook cannot affect the outcome of 'git checkout'.
1abbe475 169
0b444cdb 170It is also run after 'git clone', unless the --no-checkout (-n) option is
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171used. The first parameter given to the hook is the null-ref, the second the
172ref of the new HEAD and the flag is always 1.
173
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174This hook can be used to perform repository validity checks, auto-display
175differences from the previous HEAD if different, or set working dir metadata
176properties.
177
46232915 178post-merge
6d71c1dc 179~~~~~~~~~~
46232915 180
0b444cdb 181This hook is invoked by 'git merge', which happens when a 'git pull'
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182is done on a local repository. The hook takes a single parameter, a status
183flag specifying whether or not the merge being done was a squash merge.
0b444cdb 184This hook cannot affect the outcome of 'git merge' and is not executed,
2b3e60c2 185if the merge failed due to conflicts.
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186
187This hook can be used in conjunction with a corresponding pre-commit hook to
188save and restore any form of metadata associated with the working tree
f745acb0 189(e.g.: permissions/ownership, ACLS, etc). See contrib/hooks/setgitperms.perl
af6fb4c8 190for an example of how to do this.
46232915 191
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192pre-push
193~~~~~~~~
194
195This hook is called by 'git push' and can be used to prevent a push from taking
196place. The hook is called with two parameters which provide the name and
197location of the destination remote, if a named remote is not being used both
198values will be the same.
199
200Information about what is to be pushed is provided on the hook's standard
201input with lines of the form:
202
203 <local ref> SP <local sha1> SP <remote ref> SP <remote sha1> LF
204
205For instance, if the command +git push origin master:foreign+ were run the
206hook would receive a line like the following:
207
208 refs/heads/master 67890 refs/heads/foreign 12345
209
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210although the full, 40-character SHA-1s would be supplied. If the foreign ref
211does not yet exist the `<remote SHA-1>` will be 40 `0`. If a ref is to be
ec55559f 212deleted, the `<local ref>` will be supplied as `(delete)` and the `<local
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213SHA-1>` will be 40 `0`. If the local commit was specified by something other
214than a name which could be expanded (such as `HEAD~`, or a SHA-1) it will be
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215supplied as it was originally given.
216
217If this hook exits with a non-zero status, 'git push' will abort without
218pushing anything. Information about why the push is rejected may be sent
219to the user by writing to standard error.
220
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221[[pre-receive]]
222pre-receive
6d71c1dc 223~~~~~~~~~~~
cbb84e5d 224
ba020ef5 225This hook is invoked by 'git-receive-pack' on the remote repository,
0b444cdb 226which happens when a 'git push' is done on a local repository.
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227Just before starting to update refs on the remote repository, the
228pre-receive hook is invoked. Its exit status determines the success
229or failure of the update.
230
231This hook executes once for the receive operation. It takes no
232arguments, but for each ref to be updated it receives on standard
233input a line of the format:
234
235 <old-value> SP <new-value> SP <ref-name> LF
236
237where `<old-value>` is the old object name stored in the ref,
238`<new-value>` is the new object name to be stored in the ref and
239`<ref-name>` is the full name of the ref.
240When creating a new ref, `<old-value>` is 40 `0`.
241
242If the hook exits with non-zero status, none of the refs will be
243updated. If the hook exits with zero, updating of individual refs can
244still be prevented by the <<update,'update'>> hook.
245
24a0d61e 246Both standard output and standard error output are forwarded to
0b444cdb 247'git send-pack' on the other end, so you can simply `echo` messages
24a0d61e 248for the user.
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249
250[[update]]
6d35cc76 251update
6d71c1dc 252~~~~~~
6d35cc76 253
ba020ef5 254This hook is invoked by 'git-receive-pack' on the remote repository,
0b444cdb 255which happens when a 'git push' is done on a local repository.
6250ad1e 256Just before updating the ref on the remote repository, the update hook
37425065 257is invoked. Its exit status determines the success or failure of
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258the ref update.
259
260The hook executes once for each ref to be updated, and takes
261three parameters:
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262
263 - the name of the ref being updated,
264 - the old object name stored in the ref,
5fe8f49b 265 - and the new object name to be stored in the ref.
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266
267A zero exit from the update hook allows the ref to be updated.
ba020ef5 268Exiting with a non-zero status prevents 'git-receive-pack'
cbb84e5d 269from updating that ref.
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270
271This hook can be used to prevent 'forced' update on certain refs by
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272making sure that the object name is a commit object that is a
273descendant of the commit object named by the old object name.
a75d7b54 274That is, to enforce a "fast-forward only" policy.
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275
276It could also be used to log the old..new status. However, it
277does not know the entire set of branches, so it would end up
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278firing one e-mail per ref when used naively, though. The
279<<post-receive,'post-receive'>> hook is more suited to that.
6250ad1e 280
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281In an environment that restricts the users' access only to git
282commands over the wire, this hook can be used to implement access
283control without relying on filesystem ownership and group
284membership. See linkgit:git-shell[1] for how you might use the login
285shell to restrict the user's access to only git commands.
6d35cc76 286
24a0d61e 287Both standard output and standard error output are forwarded to
0b444cdb 288'git send-pack' on the other end, so you can simply `echo` messages
24a0d61e 289for the user.
3aadad1b 290
cbb84e5d 291The default 'update' hook, when enabled--and with
39c448c1 292`hooks.allowunannotated` config option unset or set to false--prevents
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293unannotated tags to be pushed.
294
295[[post-receive]]
296post-receive
6d71c1dc 297~~~~~~~~~~~~
6250ad1e 298
ba020ef5 299This hook is invoked by 'git-receive-pack' on the remote repository,
0b444cdb 300which happens when a 'git push' is done on a local repository.
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301It executes on the remote repository once after all the refs have
302been updated.
303
304This hook executes once for the receive operation. It takes no
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305arguments, but gets the same information as the
306<<pre-receive,'pre-receive'>>
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307hook does on its standard input.
308
ba020ef5 309This hook does not affect the outcome of 'git-receive-pack', as it
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310is called after the real work is done.
311
02783075 312This supersedes the <<post-update,'post-update'>> hook in that it gets
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313both old and new values of all the refs in addition to their
314names.
cbb84e5d 315
24a0d61e 316Both standard output and standard error output are forwarded to
0b444cdb 317'git send-pack' on the other end, so you can simply `echo` messages
24a0d61e 318for the user.
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319
320The default 'post-receive' hook is empty, but there is
321a sample script `post-receive-email` provided in the `contrib/hooks`
2de9b711 322directory in Git distribution, which implements sending commit
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323emails.
324
325[[post-update]]
6d35cc76 326post-update
6d71c1dc 327~~~~~~~~~~~
6d35cc76 328
ba020ef5 329This hook is invoked by 'git-receive-pack' on the remote repository,
0b444cdb 330which happens when a 'git push' is done on a local repository.
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331It executes on the remote repository once after all the refs have
332been updated.
333
334It takes a variable number of parameters, each of which is the
335name of ref that was actually updated.
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336
337This hook is meant primarily for notification, and cannot affect
ba020ef5 338the outcome of 'git-receive-pack'.
6d35cc76 339
45ad9b50 340The 'post-update' hook can tell what are the heads that were pushed,
6250ad1e 341but it does not know what their original and updated values are,
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342so it is a poor place to do log old..new. The
343<<post-receive,'post-receive'>> hook does get both original and
344updated values of the refs. You might consider it instead if you need
345them.
cbb84e5d 346
45ad9b50 347When enabled, the default 'post-update' hook runs
0b444cdb 348'git update-server-info' to keep the information used by dumb
45ad9b50 349transports (e.g., HTTP) up-to-date. If you are publishing
2de9b711 350a Git repository that is accessible via HTTP, you should
6250ad1e 351probably enable this hook.
3aadad1b 352
cbb84e5d 353Both standard output and standard error output are forwarded to
0b444cdb 354'git send-pack' on the other end, so you can simply `echo` messages
24a0d61e 355for the user.
0b85d926 356
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357push-to-checkout
358~~~~~~~~~~~~~~~~
359
360This hook is invoked by 'git-receive-pack' on the remote repository,
361which happens when a 'git push' is done on a local repository, when
362the push tries to update the branch that is currently checked out
363and the `receive.denyCurrentBranch` configuration variable is set to
364`updateInstead`. Such a push by default is refused if the working
365tree and the index of the remote repository has any difference from
366the currently checked out commit; when both the working tree and the
367index match the current commit, they are updated to match the newly
368pushed tip of the branch. This hook is to be used to override the
369default behaviour.
370
371The hook receives the commit with which the tip of the current
372branch is going to be updated. It can exit with a non-zero status
373to refuse the push (when it does so, it must not modify the index or
374the working tree). Or it can make any necessary changes to the
375working tree and to the index to bring them to the desired state
376when the tip of the current branch is updated to the new commit, and
377exit with a zero status.
378
379For example, the hook can simply run `git read-tree -u -m HEAD "$1"`
380in order to emulate 'git fetch' that is run in the reverse direction
381with `git push`, as the two-tree form of `read-tree -u -m` is
382essentially the same as `git checkout` that switches branches while
383keeping the local changes in the working tree that do not interfere
384with the difference between the branches.
385
386
0b85d926 387pre-auto-gc
6d71c1dc 388~~~~~~~~~~~
0b85d926 389
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390This hook is invoked by 'git gc --auto'. It takes no parameter, and
391exiting with non-zero status from this script causes the 'git gc --auto'
0b85d926 392to abort.
a5af0e2c 393
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394post-rewrite
395~~~~~~~~~~~~
396
397This hook is invoked by commands that rewrite commits (`git commit
398--amend`, 'git-rebase'; currently 'git-filter-branch' does 'not' call
399it!). Its first argument denotes the command it was invoked by:
400currently one of `amend` or `rebase`. Further command-dependent
401arguments may be passed in the future.
402
403The hook receives a list of the rewritten commits on stdin, in the
404format
405
406 <old-sha1> SP <new-sha1> [ SP <extra-info> ] LF
407
408The 'extra-info' is again command-dependent. If it is empty, the
409preceding SP is also omitted. Currently, no commands pass any
410'extra-info'.
411
6956f858 412The hook always runs after the automatic note copying (see
ad52148a 413"notes.rewrite.<command>" in linkgit:git-config[1]) has happened, and
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414thus has access to these notes.
415
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416The following command-specific comments apply:
417
418rebase::
419 For the 'squash' and 'fixup' operation, all commits that were
420 squashed are listed as being rewritten to the squashed commit.
421 This means that there will be several lines sharing the same
422 'new-sha1'.
423+
424The commits are guaranteed to be listed in the order that they were
425processed by rebase.
426
c0fc6869 427
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428GIT
429---
9e1f0a85 430Part of the linkgit:git[1] suite