[GSoC][PATCH] commit: add a commit.signOff config variable

[Chen Jingpiao <chenjingpiao@gmail.com>]

Add the commit.signOff configuration variable to use the -s or --signoff
option of git commit by default.

Signed-off-by: Chen Jingpiao <chenjingpiao@gmail.com>
---

Though we can configure signoff using format.signOff variable. Someone like to
add Signed-off-by line by the committer.

 Documentation/config.txt     |  4 +++
 Documentation/git-commit.txt |  2 ++
 builtin/commit.c             |  4 +++
 t/t7501-commit.sh            | 69 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 79 insertions(+)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 0e25b2c92..5dec3f0cb 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1303,6 +1303,10 @@ commit.gpgSign::
 	convenient to use an agent to avoid typing your GPG passphrase
 	several times.
 
+commit.signOff::
+	A boolean value which lets you enable the `-s/--signoff` option of
+	`git commit` by default. See linkgit:git-commit[1].
+
 commit.status::
 	A boolean to enable/disable inclusion of status information in the
 	commit message template when using an editor to prepare the commit
diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt
index f970a4342..7a28ea765 100644
--- a/Documentation/git-commit.txt
+++ b/Documentation/git-commit.txt
@@ -166,6 +166,8 @@ The `-m` option is mutually exclusive with `-c`, `-C`, and `-F`.
 	the rights to submit this work under the same license and
 	agrees to a Developer Certificate of Origin
 	(see http://developercertificate.org/ for more information).
+	See the `commit.signOff` configuration variable in
+	linkgit:git-config[1].
 
 -n::
 --no-verify::
diff --git a/builtin/commit.c b/builtin/commit.c
index 4610e3d8e..324213254 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1548,6 +1548,10 @@ static int git_commit_config(const char *k, const char *v, void *cb)
 		sign_commit = git_config_bool(k, v) ? "" : NULL;
 		return 0;
 	}
+	if (!strcmp(k, "commit.signoff")) {
+		signoff = git_config_bool(k, v);
+		return 0;
+	}
 	if (!strcmp(k, "commit.verbose")) {
 		int is_bool;
 		config_commit_verbose = git_config_bool_or_int(k, v, &is_bool);
diff --git a/t/t7501-commit.sh b/t/t7501-commit.sh
index fa61b1a4e..46733ed2a 100755
--- a/t/t7501-commit.sh
+++ b/t/t7501-commit.sh
@@ -505,6 +505,75 @@ Myfooter: x" &&
 	test_cmp expected actual
 '
 
+test_expect_success "commit.signoff=true and --signoff omitted" '
+	echo 7 >positive &&
+	git add positive &&
+	git -c commit.signoff=true commit -m "thank you" &&
+	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
+	(
+		echo thank you
+		echo
+		git var GIT_COMMITTER_IDENT |
+		sed -e "s/>.*/>/" -e "s/^/Signed-off-by: /"
+	) >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success "commit.signoff=true and --signoff" '
+	echo 8 >positive &&
+	git add positive &&
+	git -c commit.signoff=true commit --signoff -m "thank you" &&
+	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
+	(
+		echo thank you
+		echo
+		git var GIT_COMMITTER_IDENT |
+		sed -e "s/>.*/>/" -e "s/^/Signed-off-by: /"
+	) >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success "commit.signoff=true and --no-signoff" '
+	echo 9 >positive &&
+	git add positive &&
+	git -c commit.signoff=true commit --no-signoff -m "thank you" &&
+	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
+	echo thank you >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success "commit.signoff=false and --signoff omitted" '
+	echo 10 >positive &&
+	git add positive &&
+	git -c commit.signoff=false commit -m "thank you" &&
+	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
+	echo thank you >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success "commit.signoff=false and --signoff" '
+	echo 11 >positive &&
+	git add positive &&
+	git -c commit.signoff=false commit --signoff -m "thank you" &&
+	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
+	(
+		echo thank you
+		echo
+		git var GIT_COMMITTER_IDENT |
+		sed -e "s/>.*/>/" -e "s/^/Signed-off-by: /"
+	) >expected &&
+	test_cmp expected actual
+'
+
+test_expect_success "commit.signoff=false and --no-signoff" '
+	echo 12 >positive &&
+	git add positive &&
+	git -c commit.signoff=false commit --no-signoff -m "thank you" &&
+	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
+	echo thank you >expected &&
+	test_cmp expected actual
+'
+
 test_expect_success 'multiple -m' '
 
 	>negative &&
-- 
2.16.1.70.g5ccd54536