githooks(5)
NAME
githooks - Hooks used by Git
SYNOPSIS
$GIT_DIR/hooks/* (or `git config core.hooksPath`/*)
DESCRIPTION
Hooks are programs you can place in a hooks directory to trigger actions at certain points in git's execution. Hooks that don't have the executable bit set are ignored. By default the hooks directory is $GIT_DIR/hooks, but that can be changed via the core.hooksPath configuration variable (see git- config(1)). Before Git invokes a hook, it changes its working directory to either the root of the working tree in a non-bare repository, or to the $GIT_DIR in a bare repository. Hooks can get their arguments via the environment, command-line arguments, and stdin. See the documentation for each hook below for details. git init may copy hooks to the new repository, depending on its configuration. See the "TEMPLATE DIRECTORY" section in git-init(1) for details. When the rest of this document refers to "default hooks" it's talking about the default template shipped with Git. The currently supported hooks are described below.
HOOKS
applypatch-msg
This hook is invoked by git am. It takes a single parameter, the name
of the file that holds the proposed commit log message. Exiting with a
non-zero status causes git am to abort before applying the patch.
The hook is allowed to edit the message file in place, and can be used
to normalize the message into some project standard format. It can also
be used to refuse the commit after inspecting the message file.
The default applypatch-msg hook, when enabled, runs the commit-msg
hook, if the latter is enabled.
pre-applypatch
This hook is invoked by git am. It takes no parameter, and is invoked
after the patch is applied, but before a commit is made.
If it exits with non-zero status, then the working tree will not be
committed after applying the patch.
It can be used to inspect the current working tree and refuse to make a
commit if it does not pass certain test.
The default pre-applypatch hook, when enabled, runs the pre-commit
hook, if the latter is enabled.
post-applypatch
This hook is invoked by git am. It takes no parameter, and is invoked
after the patch is applied and a commit is made.
This hook is meant primarily for notification, and cannot affect the
outcome of git am.
pre-commit
This hook is invoked by git commit, and can be bypassed with the
--no-verify option. It takes no parameters, and is invoked before
obtaining the proposed commit log message and making a commit. Exiting
with a non-zero status from this script causes the git commit command
to abort before creating a commit.
The default pre-commit hook, when enabled, catches introduction of
lines with trailing whitespaces and aborts the commit when such a line
is found.
All the git commit hooks are invoked with the environment variable
GIT_EDITOR=: if the command will not bring up an editor to modify the
commit message.
prepare-commit-msg
This hook is invoked by git commit right after preparing the default
log message, and before the editor is started.
It takes one to three parameters. The first is the name of the file
that contains the commit log message. The second is the source of the
commit message, and can be: message (if a -m or -F option was given);
template (if a -t option was given or the configuration option
commit.template is set); merge (if the commit is a merge or a
.git/MERGE_MSG file exists); squash (if a .git/SQUASH_MSG file exists);
or commit, followed by a commit SHA-1 (if a -c, -C or --amend option
was given).
If the exit status is non-zero, git commit will abort.
The purpose of the hook is to edit the message file in place, and it is
not suppressed by the --no-verify option. A non-zero exit means a
failure of the hook and aborts the commit. It should not be used as
replacement for pre-commit hook.
The sample prepare-commit-msg hook that comes with Git comments out the
Conflicts: part of a merge's commit message.
commit-msg
This hook is invoked by git commit, and can be bypassed with the
--no-verify option. It takes a single parameter, the name of the file
that holds the proposed commit log message. Exiting with a non-zero
status causes the git commit to abort.
The hook is allowed to edit the message file in place, and can be used
to normalize the message into some project standard format. It can also
be used to refuse the commit after inspecting the message file.
The default commit-msg hook, when enabled, detects duplicate
"Signed-off-by" lines, and aborts the commit if one is found.
post-commit
This hook is invoked by git commit. It takes no parameters, and is
invoked after a commit is made.
This hook is meant primarily for notification, and cannot affect the
outcome of git commit.
pre-rebase
This hook is called by git rebase and can be used to prevent a branch
from getting rebased. The hook may be called with one or two
parameters. The first parameter is the upstream from which the series
was forked. The second parameter is the branch being rebased, and is
not set when rebasing the current branch.
post-checkout
This hook is invoked when a git checkout is run after having updated
the worktree. The hook is given three parameters: the ref of the
previous HEAD, the ref of the new HEAD (which may or may not have
changed), and a flag indicating whether the checkout was a branch
checkout (changing branches, flag=1) or a file checkout (retrieving a
file from the index, flag=0). This hook cannot affect the outcome of
git checkout.
It is also run after git clone, unless the --no-checkout (-n) option is
used. The first parameter given to the hook is the null-ref, the second
the ref of the new HEAD and the flag is always 1.
This hook can be used to perform repository validity checks,
auto-display differences from the previous HEAD if different, or set
working dir metadata properties.
post-merge
This hook is invoked by git merge, which happens when a git pull is
done on a local repository. The hook takes a single parameter, a status
flag specifying whether or not the merge being done was a squash merge.
This hook cannot affect the outcome of git merge and is not executed,
if the merge failed due to conflicts.
This hook can be used in conjunction with a corresponding pre-commit
hook to save and restore any form of metadata associated with the
working tree (e.g.: permissions/ownership, ACLS, etc). See
contrib/hooks/setgitperms.perl for an example of how to do this.
pre-push
This hook is called by git push and can be used to prevent a push from
taking place. The hook is called with two parameters which provide the
name and location of the destination remote, if a named remote is not
being used both values will be the same.
Information about what is to be pushed is provided on the hook's
standard input with lines of the form:
<local ref> SP <local sha1> SP <remote ref> SP <remote sha1> LF
For instance, if the command git push origin master:foreign were run
the hook would receive a line like the following:
refs/heads/master 67890 refs/heads/foreign 12345
although the full, 40-character SHA-1s would be supplied. If the
foreign ref does not yet exist the <remote SHA-1> will be 40 0. If a
ref is to be deleted, the <local ref> will be supplied as (delete) and
the <local SHA-1> will be 40 0. If the local commit was specified by
something other than a name which could be expanded (such as HEAD~, or
a SHA-1) it will be supplied as it was originally given.
If this hook exits with a non-zero status, git push will abort without
pushing anything. Information about why the push is rejected may be
sent to the user by writing to standard error.
pre-receive
This hook is invoked by git-receive-pack on the remote repository,
which happens when a git push is done on a local repository. Just
before starting to update refs on the remote repository, the
pre-receive hook is invoked. Its exit status determines the success or
failure of the update.
This hook executes once for the receive operation. It takes no
arguments, but for each ref to be updated it receives on standard input
a line of the format:
<old-value> SP <new-value> SP <ref-name> LF
where <old-value> is the old object name stored in the ref, <new-value>
is the new object name to be stored in the ref and <ref-name> is the
full name of the ref. When creating a new ref, <old-value> is 40 0.
If the hook exits with non-zero status, none of the refs will be
updated. If the hook exits with zero, updating of individual refs can
still be prevented by the update hook.
Both standard output and standard error output are forwarded to git
send-pack on the other end, so you can simply echo messages for the
user.
The number of push options given on the command line of git push
--push-option=... can be read from the environment variable
GIT_PUSH_OPTION_COUNT, and the options themselves are found in
GIT_PUSH_OPTION_0, GIT_PUSH_OPTION_1,... If it is negotiated to not use
the push options phase, the environment variables will not be set. If
the client selects to use push options, but doesn't transmit any, the
count variable will be set to zero, GIT_PUSH_OPTION_COUNT=0.
update
This hook is invoked by git-receive-pack on the remote repository,
which happens when a git push is done on a local repository. Just
before updating the ref on the remote repository, the update hook is
invoked. Its exit status determines the success or failure of the ref
update.
The hook executes once for each ref to be updated, and takes three
parameters:
* the name of the ref being updated,
* the old object name stored in the ref,
* and the new object name to be stored in the ref.
A zero exit from the update hook allows the ref to be updated. Exiting
with a non-zero status prevents git-receive-pack from updating that
ref.
This hook can be used to prevent forced update on certain refs by
making sure that the object name is a commit object that is a
descendant of the commit object named by the old object name. That is,
to enforce a "fast-forward only" policy.
It could also be used to log the old..new status. However, it does not
know the entire set of branches, so it would end up firing one e-mail
per ref when used naively, though. The post-receive hook is more suited
to that.
In an environment that restricts the users' access only to git commands
over the wire, this hook can be used to implement access control
without relying on filesystem ownership and group membership. See git-
shell(1) for how you might use the login shell to restrict the user's
access to only git commands.
Both standard output and standard error output are forwarded to git
send-pack on the other end, so you can simply echo messages for the
user.
The default update hook, when enabled---and with hooks.allowunannotated
config option unset or set to false---prevents unannotated tags to be
pushed.
post-receive
This hook is invoked by git-receive-pack on the remote repository,
which happens when a git push is done on a local repository. It
executes on the remote repository once after all the refs have been
updated.
This hook executes once for the receive operation. It takes no
arguments, but gets the same information as the pre-receive hook does
on its standard input.
This hook does not affect the outcome of git-receive-pack, as it is
called after the real work is done.
This supersedes the post-update hook in that it gets both old and new
values of all the refs in addition to their names.
Both standard output and standard error output are forwarded to git
send-pack on the other end, so you can simply echo messages for the
user.
The default post-receive hook is empty, but there is a sample script
post-receive-email provided in the contrib/hooks directory in Git
distribution, which implements sending commit emails.
The number of push options given on the command line of git push
--push-option=... can be read from the environment variable
GIT_PUSH_OPTION_COUNT, and the options themselves are found in
GIT_PUSH_OPTION_0, GIT_PUSH_OPTION_1,... If it is negotiated to not use
the push options phase, the environment variables will not be set. If
the client selects to use push options, but doesn't transmit any, the
count variable will be set to zero, GIT_PUSH_OPTION_COUNT=0.
post-update
This hook is invoked by git-receive-pack on the remote repository,
which happens when a git push is done on a local repository. It
executes on the remote repository once after all the refs have been
updated.
It takes a variable number of parameters, each of which is the name of
ref that was actually updated.
This hook is meant primarily for notification, and cannot affect the
outcome of git-receive-pack.
The post-update hook can tell what are the heads that were pushed, but
it does not know what their original and updated values are, so it is a
poor place to do log old..new. The post-receive hook does get both
original and updated values of the refs. You might consider it instead
if you need them.
When enabled, the default post-update hook runs git update-server-info
to keep the information used by dumb transports (e.g., HTTP)
up-to-date. If you are publishing a Git repository that is accessible
via HTTP, you should probably enable this hook.
Both standard output and standard error output are forwarded to git
send-pack on the other end, so you can simply echo messages for the
user.
push-to-checkout
This hook is invoked by git-receive-pack on the remote repository,
which happens when a git push is done on a local repository, when the
push tries to update the branch that is currently checked out and the
receive.denyCurrentBranch configuration variable is set to
updateInstead. Such a push by default is refused if the working tree
and the index of the remote repository has any difference from the
currently checked out commit; when both the working tree and the index
match the current commit, they are updated to match the newly pushed
tip of the branch. This hook is to be used to override the default
behaviour.
The hook receives the commit with which the tip of the current branch
is going to be updated. It can exit with a non-zero status to refuse
the push (when it does so, it must not modify the index or the working
tree). Or it can make any necessary changes to the working tree and to
the index to bring them to the desired state when the tip of the
current branch is updated to the new commit, and exit with a zero
status.
For example, the hook can simply run git read-tree -u -m HEAD "$1" in
order to emulate git fetch that is run in the reverse direction with
git push, as the two-tree form of read-tree -u -m is essentially the
same as git checkout that switches branches while keeping the local
changes in the working tree that do not interfere with the difference
between the branches.
pre-auto-gc
This hook is invoked by git gc --auto. It takes no parameter, and
exiting with non-zero status from this script causes the git gc --auto
to abort.
post-rewrite
This hook is invoked by commands that rewrite commits (git commit
--amend, git-rebase; currently git-filter-branch does not call it!).
Its first argument denotes the command it was invoked by: currently one
of amend or rebase. Further command-dependent arguments may be passed
in the future.
The hook receives a list of the rewritten commits on stdin, in the
format
<old-sha1> SP <new-sha1> [ SP <extra-info> ] LF
The extra-info is again command-dependent. If it is empty, the
preceding SP is also omitted. Currently, no commands pass any
extra-info.
The hook always runs after the automatic note copying (see
"notes.rewrite.<command>" in git-config(1)) has happened, and thus has
access to these notes.
The following command-specific comments apply:
rebase
For the squash and fixup operation, all commits that were squashed
are listed as being rewritten to the squashed commit. This means
that there will be several lines sharing the same new-sha1.
The commits are guaranteed to be listed in the order that they were
processed by rebase.
GIT
Part of the git(1) suite
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