Teach git-commit about commit message templates.

These are useful in organizations that enforce particular formats
for commit messages, e.g., to specify bug IDs or test plans.
Use of the template is not enforced; it is simply used as the
initial content when the editor is invoked.

Signed-off-by: Steven Grimm <koreth@midwinter.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-commit.txt

@@ -74,6 +74,14 @@ OPTIONS
 -m <msg>|--message=<msg>::
 	Use the given <msg> as the commit message.
 
+-t <file>|--template=<file>::
+	Use the contents of the given file as the initial version
+	of the commit message. The editor is invoked and you can
+	make subsequent changes. If a message is specified using
+	the `-m` or `-F` options, this option has no effect. The
+	template file may also be specified using the `commit.template`
+	configuration variable.
+
 -s|--signoff::
 	Add Signed-off-by line at the end of the commit message.
 

git-commit.sh

@@ -3,7 +3,7 @@
 # Copyright (c) 2005 Linus Torvalds
 # Copyright (c) 2006 Junio C Hamano
 
-USAGE='[-a | --interactive] [-s] [-v] [--no-verify] [-m <message> | -F <logfile> | (-C|-c) <commit> | --amend] [-u] [-e] [--author <author>] [[-i | -o] <path>...]'
+USAGE='[-a | --interactive] [-s] [-v] [--no-verify] [-m <message> | -F <logfile> | (-C|-c) <commit> | --amend] [-u] [-e] [--author <author>] [--template <file>] [[-i | -o] <path>...]'
 SUBDIRECTORY_OK=Yes
 . git-sh-setup
 require_work_tree
@@ -87,6 +87,7 @@ signoff=
 force_author=
 only_include_assumed=
 untracked_files=
+templatefile="`git config commit.template`"
 while case "$#" in 0) break;; esac
 do
 	case "$1" in
@@ -248,6 +249,13 @@ $1"
 		signoff=t
 		shift
 		;;
+	-t|--t|--te|--tem|--temp|--templ|--templa|--templat|--template)
+		case "$#" in 1) usage ;; esac
+		shift
+		templatefile="$1"
+		no_edit=
+		shift
+		;;
 	-q|--q|--qu|--qui|--quie|--quiet)
 		quiet=t
 		shift
@@ -321,6 +329,14 @@ t,,[1-9]*)
 	die "No paths with -i does not make sense." ;;
 esac
 
+if test ! -z "$templatefile" -a -z "$log_given"
+then
+	if test ! -f "$templatefile"
+	then
+		die "Commit template file does not exist."
+	fi
+fi
+
 ################################################################
 # Prepare index to have a tree to be committed
 
@@ -454,6 +470,9 @@ then
 elif test -f "$GIT_DIR/SQUASH_MSG"
 then
 	cat "$GIT_DIR/SQUASH_MSG"
+elif test "$templatefile" != ""
+then
+	cat "$templatefile"
 fi | git stripspace >"$GIT_DIR"/COMMIT_EDITMSG
 
 case "$signoff" in
@@ -572,10 +591,35 @@ else
 fi |
 git stripspace >"$GIT_DIR"/COMMIT_MSG
 
-if cnt=`grep -v -i '^Signed-off-by' "$GIT_DIR"/COMMIT_MSG |
-	git stripspace |
-	wc -l` &&
-   test 0 -lt $cnt
+# Test whether the commit message has any content we didn't supply.
+have_commitmsg=
+grep -v -i '^Signed-off-by' "$GIT_DIR"/COMMIT_MSG |
+	git stripspace > "$GIT_DIR"/COMMIT_BAREMSG
+
+# Is the commit message totally empty?
+if test -s "$GIT_DIR"/COMMIT_BAREMSG
+then
+	if test "$templatefile" != ""
+	then
+		# Test whether this is just the unaltered template.
+		if cnt=`sed -e '/^#/d' < "$templatefile" |
+			git stripspace |
+			diff "$GIT_DIR"/COMMIT_BAREMSG - |
+			wc -l` &&
+		   test 0 -lt $cnt
+		then
+			have_commitmsg=t
+		fi
+	else
+		# No template, so the content in the commit message must
+		# have come from the user.
+		have_commitmsg=t
+	fi
+fi
+
+rm -f "$GIT_DIR"/COMMIT_BAREMSG
+
+if test "$have_commitmsg" = "t"
 then
 	if test -z "$TMP_INDEX"
 	then

t/t7500-commit.sh

@@ -0,0 +1,96 @@
+#!/bin/sh
+#
+# Copyright (c) 2007 Steven Grimm
+#
+
+test_description='git-commit
+
+Tests for selected commit options.'
+
+. ./test-lib.sh
+
+commit_msg_is () {
+	test "`git log --pretty=format:%s%b -1`" = "$1"
+}
+
+# A sanity check to see if commit is working at all.
+test_expect_success 'a basic commit in an empty tree should succeed' '
+	echo content > foo &&
+	git add foo &&
+	git commit -m "initial commit"
+'
+
+test_expect_success 'nonexistent template file should return error' '
+	echo changes >> foo &&
+	git add foo &&
+	! git commit --template "$PWD"/notexist
+'
+
+test_expect_success 'nonexistent template file in config should return error' '
+	git config commit.template "$PWD"/notexist &&
+	! git commit &&
+	git config --unset commit.template
+'
+
+# From now on we'll use a template file that exists.
+TEMPLATE="$PWD"/template
+
+test_expect_success 'unedited template should not commit' '
+	echo "template line" > "$TEMPLATE" &&
+	! git commit --template "$TEMPLATE"
+'
+
+test_expect_success 'unedited template with comments should not commit' '
+	echo "# comment in template" >> "$TEMPLATE" &&
+	! git commit --template "$TEMPLATE"
+'
+
+test_expect_success 'a Signed-off-by line by itself should not commit' '
+	! GIT_EDITOR=../t7500/add-signed-off git commit --template "$TEMPLATE"
+'
+
+test_expect_success 'adding comments to a template should not commit' '
+	! GIT_EDITOR=../t7500/add-comments git commit --template "$TEMPLATE"
+'
+
+test_expect_success 'adding real content to a template should commit' '
+	GIT_EDITOR=../t7500/add-content git commit --template "$TEMPLATE" &&
+	commit_msg_is "template linecommit message"
+'
+
+test_expect_success '-t option should be short for --template' '
+	echo "short template" > "$TEMPLATE" &&
+	echo "new content" >> foo &&
+	git add foo &&
+	GIT_EDITOR=../t7500/add-content git commit -t "$TEMPLATE" &&
+	commit_msg_is "short templatecommit message"
+'
+
+test_expect_success 'config-specified template should commit' '
+	echo "new template" > "$TEMPLATE" &&
+	git config commit.template "$TEMPLATE" &&
+	echo "more content" >> foo &&
+	git add foo &&
+	GIT_EDITOR=../t7500/add-content git commit &&
+	git config --unset commit.template &&
+	commit_msg_is "new templatecommit message"
+'
+
+test_expect_success 'explicit commit message should override template' '
+	echo "still more content" >> foo &&
+	git add foo &&
+	GIT_EDITOR=../t7500/add-content git commit --template "$TEMPLATE" \
+		-m "command line msg" &&
+	commit_msg_is "command line msg<unknown>"
+'
+
+test_expect_success 'commit message from file should override template' '
+	echo "content galore" >> foo &&
+	git add foo &&
+	echo "standard input msg" |
+		GIT_EDITOR=../t7500/add-content git commit \
+			--template "$TEMPLATE" --file - &&
+	commit_msg_is "standard input msg<unknown>"
+'
+
+test_done

t/t7500/add-comments

@@ -0,0 +1,4 @@
+#!/bin/sh
+echo "# this is a new comment" >> "$1"
+echo "# and so is this" >> "$1"
+exit 0

t/t7500/add-content

@@ -0,0 +1,3 @@
+#!/bin/sh
+echo "commit message" >> "$1"
+exit 0

t/t7500/add-signed-off

@@ -0,0 +1,3 @@
+#!/bin/sh
+echo "Signed-off-by: foo <bar@frotz>" >> "$1"
+exit 0