Paolo BonziniThe prepare-commit-msg hook is run whenever a "fresh" commit message (i.e. not one taken from another commit with -c) is shown in the editor. It can modify the commit message in-place and/or abort the commit.
While the default hook just adds a Signed-Off-By line at the bottom of the commit messsage, the hook is more intended to build a template for the commit message following project standards.
Signed-Off-By: Paolo Bonzini <bonzini@gnu.org> --- Documentation/git-commit.txt | 13 ++++++++----- Documentation/hooks.txt | 21 +++++++++++++++++++++ builtin-commit.c | 3 +++ templates/hooks--commit-msg | 3 +++ templates/hooks--prepare-commit-msg | 14 ++++++++++++++ 5 files changed, 49 insertions(+), 5 deletions(-) create mode 100644 templates/hooks--prepare-commit-msg
The real motivation for this is building the commit message from GNU ChangeLogs. But I figured that putting it in the real commit message rather than a cover letter would have implied rejection of the patch...
Show changes to 5 files +49 −5
Documentation/git-commit.txt, Documentation/hooks.txt, builtin-commit.c, templates/hooks--commit-msg, templates/hooks--prepare-commit-msg
diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt index c3725b2..c68191b 100644 --- a/Documentation/git-commit.txt +++ b/Documentation/git-commit.txt @@ -62,18 +62,21 @@ OPTIONS and the authorship information (including the timestamp) when creating the commit. With '-C', the editor is not invoked; with '-c' the user can further edit the commit - message. + message. In either case, the prepare-commit-msg hook is + bypassed. -F <file>:: Take the commit message from the given file. Use '-' to - read the message from the standard input. + read the message from the standard input. This option + bypasses the prepare-commit-msg hook. --author <author>:: Override the author name used in the commit. Use `A U Thor <author@example.com>` format. -m <msg>|--message=<msg>:: - Use the given <msg> as the commit message. + Use the given <msg> as the commit message. This option + bypasses the prepare-commit-msg hook. -t <file>|--template=<file>:: Use the contents of the given file as the initial version @@ -280,8 +283,8 @@ order). HOOKS ----- -This command can run `commit-msg`, `pre-commit`, and -`post-commit` hooks. See link:hooks.html[hooks] for more +This command can run `commit-msg`, `prepare-commit-msg`, `pre-commit`, +and `post-commit` hooks. See link:hooks.html[hooks] for more information. diff --git a/Documentation/hooks.txt b/Documentation/hooks.txt index f110162..2ef5567 100644 --- a/Documentation/hooks.txt +++ b/Documentation/hooks.txt @@ -61,6 +61,27 @@ The default 'pre-commit' hook, when enabled, catches introduction of lines with trailing whitespaces and aborts the commit when such a line is found. +prepare-commit-msg +------------------ + +This hook is invoked by `git-commit` right before starting the editor +with an empty log message. It is not executed if the commit message is +specified otherwise, such as with the `\-m`, `\-F`, `\-c`, `\-C` options. +It takes a single parameter, the name of the file that holds git's own +template commit log message. Exiting with non-zero status causes +`git-commit` to abort. + +The hook is allowed to edit the message file in place, and +can be used to augment the default commit message with some +project standard information. It can also be used for the same +purpose as the pre-commit message, if the verification has +to be skipped for automatic commits (e.g. during rebasing). + +The default 'prepare-commit-msg' hook adds a Signed-Off-By line +(doing it with a hook is not necessarily a good idea, but doing +it in 'commit-msg' is worse because you are not reminded in +the editor). + commit-msg ---------- diff --git a/builtin-commit.c b/builtin-commit.c index 0227936..1de0d02 100644 --- a/builtin-commit.c +++ b/builtin-commit.c @@ -869,6 +869,9 @@ int cmd_commit(int argc, const char **argv, const char *prefix) char index[PATH_MAX]; const char *env[2] = { index, NULL }; snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", index_file); + if (!edit_message) { + run_hook(index_file, "prepare-commit-msg", git_path(commit_editmsg)); + } launch_editor(git_path(commit_editmsg), NULL, env); } if (!no_verify && diff --git a/templates/hooks--commit-msg b/templates/hooks--commit-msg index c5cdb9d..4ef86eb 100644 --- a/templates/hooks--commit-msg +++ b/templates/hooks--commit-msg @@ -9,6 +9,9 @@ # To enable this hook, make this file executable. # Uncomment the below to add a Signed-off-by line to the message. +# Doing this in a hook is a bad idea in general, but the prepare-commit-msg +# hook is more suited to it. +# # SOB=$(git var GIT_AUTHOR_IDENT | sed -n 's/^\(.*>\).*$/Signed-off-by: \1/p') # grep -qs "^$SOB" "$1" || echo "$SOB" >> "$1" diff --git a/templates/hooks--prepare-commit-msg b/templates/hooks--prepare-commit-msg new file mode 100644 index 0000000..176283b --- /dev/null +++ b/templates/hooks--prepare-commit-msg @@ -0,0 +1,14 @@ +#!/bin/sh +# +# An example hook script to prepare the commit log message. +# Called by git-commit with one argument, the name of the file +# that has the commit message. The hook should exit with non-zero +# status after issuing an appropriate message if it wants to stop the +# commit. The hook is allowed to edit the commit message file. +# +# To enable this hook, make this file executable. + +# This example adds a Signed-off-by line to the message, that can +# still be edited. +SOB=$(git var GIT_AUTHOR_IDENT | sed -n 's/^\(.*>\).*$/Signed-off-by: \1/p') +grep -qs "^$SOB" "$1" || echo "$SOB" >> "$1"
-- 1.5.3.4.910.gc5122-dirty
