Merge branch 'ab/hooks'

A new configuration variable core.hooksPath allows customizing
where the hook directory is.

* ab/hooks:
  hooks: allow customizing where the hook directory is
  githooks.txt: minor improvements to the grammar & phrasing
  githooks.txt: amend dangerous advice about 'update' hook ACL
  githooks.txt: improve the intro section

Documentation/config.txt

@@ -618,6 +618,23 @@ core.attributesFile::
 	$XDG_CONFIG_HOME/git/attributes. If $XDG_CONFIG_HOME is either not
 	set or empty, $HOME/.config/git/attributes is used instead.
 
+core.hooksPath::
+	By default Git will look for your hooks in the
+	'$GIT_DIR/hooks' directory. Set this to different path,
+	e.g. '/etc/git/hooks', and Git will try to find your hooks in
+	that directory, e.g. '/etc/git/hooks/pre-receive' instead of
+	in '$GIT_DIR/hooks/pre-receive'.
++
+The path can be either absolute or relative. A relative path is
+taken as relative to the directory where the hooks are run (see
+the "DESCRIPTION" section of linkgit:githooks[5]).
++
+This configuration variable is useful in cases where you'd like to
+centrally configure your Git hooks instead of configuring them on a
+per-repository basis, or as a more flexible and centralized
+alternative to having an `init.templateDir` where you've changed
+default hooks.
+
 core.editor::
 	Commands such as `commit` and `tag` that lets you edit
 	messages by launching an editor uses the value of this

Documentation/git-init.txt

@@ -130,7 +130,12 @@ The template directory will be one of the following (in order):
  - the default template directory: `/usr/share/git-core/templates`.
 
 The default template directory includes some directory structure, suggested
-"exclude patterns" (see linkgit:gitignore[5]), and sample hook files (see linkgit:githooks[5]).
+"exclude patterns" (see linkgit:gitignore[5]), and sample hook files.
+
+The sample hooks are all disabled by default, To enable one of the
+sample hooks rename it by removing its `.sample` suffix.
+
+See linkgit:githooks[5] for more general info on hook execution.
 
 EXAMPLES
 --------

Documentation/githooks.txt

@@ -7,24 +7,35 @@ githooks - Hooks used by Git
 
 SYNOPSIS
 --------
-$GIT_DIR/hooks/*
+$GIT_DIR/hooks/* (or \`git config core.hooksPath`/*)
 
 
 DESCRIPTION
 -----------
 
-Hooks are little scripts you can place in `$GIT_DIR/hooks`
-directory to trigger action at certain points.  When
-'git init' is run, a handful of example hooks are copied into the
-`hooks` directory of the new repository, but by default they are
-all disabled.  To enable a hook, rename it by removing its `.sample`
-suffix.
+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.
 
-NOTE: It is also a requirement for a given hook to be executable.
-However - in a freshly initialized repository - the `.sample` files are
-executable by default.
+By default the hooks directory is `$GIT_DIR/hooks`, but that can be
+changed via the `core.hooksPath` configuration variable (see
+linkgit:git-config[1]).
 
-This document describes the currently defined hooks.
+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
+linkgit: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
 -----
@@ -32,15 +43,15 @@ HOOKS
 applypatch-msg
 ~~~~~~~~~~~~~~
 
-This hook is invoked by 'git am' script.  It takes a single
+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 non-zero status causes
-'git am' to abort before applying the patch.
+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 (if the project has one). It can also be used to refuse
-the commit after inspecting the message file.
+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.
@@ -73,10 +84,10 @@ pre-commit
 ~~~~~~~~~~
 
 This hook is invoked by 'git commit', and can be bypassed
-with `--no-verify` option.  It takes no parameter, and is
+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 non-zero status from this script
-causes the 'git commit' to abort.
+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
@@ -115,15 +126,15 @@ commit-msg
 ~~~~~~~~~~
 
 This hook is invoked by 'git commit', and can be bypassed
-with `--no-verify` option.  It takes a single parameter, the
+with the `--no-verify` option.  It takes a single parameter, the
 name of the file that holds the proposed commit log message.
-Exiting with non-zero status causes the 'git commit' to
+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 (if the project has one). It can also be used to refuse
-the commit after inspecting the message file.
+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.
@@ -131,8 +142,8 @@ The default 'commit-msg' hook, when enabled, detects duplicate
 post-commit
 ~~~~~~~~~~~
 
-This hook is invoked by 'git commit'.  It takes no
-parameter, and is invoked after a commit is made.
+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'.
@@ -267,9 +278,11 @@ 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,'post-receive'>> hook is more suited to that.
 
-Another use suggested on the mailing list is to use this hook to
-implement access control which is finer grained than the one
-based on filesystem group.
+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 linkgit: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

cache.h

@@ -654,6 +654,7 @@ extern int warn_on_object_refname_ambiguity;
 extern const char *apply_default_whitespace;
 extern const char *apply_default_ignorewhitespace;
 extern const char *git_attributes_file;
+extern const char *git_hooks_path;
 extern int zlib_compression_level;
 extern int core_compression_level;
 extern int core_compression_seen;

config.c

@@ -717,6 +717,9 @@ static int git_default_core_config(const char *var, const char *value)
 	if (!strcmp(var, "core.attributesfile"))
 		return git_config_pathname(&git_attributes_file, var, value);
 
+	if (!strcmp(var, "core.hookspath"))
+		return git_config_pathname(&git_hooks_path, var, value);
+
 	if (!strcmp(var, "core.bare")) {
 		is_bare_repository_cfg = git_config_bool(var, value);
 		return 0;

environment.c

@@ -31,6 +31,7 @@ const char *git_log_output_encoding;
 const char *apply_default_whitespace;
 const char *apply_default_ignorewhitespace;
 const char *git_attributes_file;
+const char *git_hooks_path;
 int zlib_compression_level = Z_BEST_SPEED;
 int core_compression_level;
 int core_compression_seen;

run-command.c

@@ -825,7 +825,10 @@ const char *find_hook(const char *name)
 	static struct strbuf path = STRBUF_INIT;
 
 	strbuf_reset(&path);
-	strbuf_git_path(&path, "hooks/%s", name);
+	if (git_hooks_path)
+		strbuf_addf(&path, "%s/%s", git_hooks_path, name);
+	else
+		strbuf_git_path(&path, "hooks/%s", name);
 	if (access(path.buf, X_OK) < 0)
 		return NULL;
 	return path.buf;

t/t1350-config-hooks-path.sh

@@ -0,0 +1,37 @@
+#!/bin/sh
+
+test_description='Test the core.hooksPath configuration variable'
+
+. ./test-lib.sh
+
+test_expect_success 'set up a pre-commit hook in core.hooksPath' '
+	mkdir -p .git/custom-hooks .git/hooks &&
+	write_script .git/custom-hooks/pre-commit <<-\EOF &&
+	echo CUSTOM >>actual
+	EOF
+	write_script .git/hooks/pre-commit <<-\EOF
+	echo NORMAL >>actual
+	EOF
+'
+
+test_expect_success 'Check that various forms of specifying core.hooksPath work' '
+	test_commit no_custom_hook &&
+	git config core.hooksPath .git/custom-hooks &&
+	test_commit have_custom_hook &&
+	git config core.hooksPath .git/custom-hooks/ &&
+	test_commit have_custom_hook_trailing_slash &&
+	git config core.hooksPath "$PWD/.git/custom-hooks" &&
+	test_commit have_custom_hook_abs_path &&
+	git config core.hooksPath "$PWD/.git/custom-hooks/" &&
+	test_commit have_custom_hook_abs_path_trailing_slash &&
+	cat >expect <<-\EOF &&
+	NORMAL
+	CUSTOM
+	CUSTOM
+	CUSTOM
+	CUSTOM
+	EOF
+	test_cmp expect actual
+'
+
+test_done