[PATCH v3] commit-tree: add missing --gpg-sign flag

[Brandon Richardson <brandon1024.br@gmail.com>]

Add --gpg-sign option in commit-tree, which was documented, but not
implemented, in 55ca3f99ae. Add tests for the --gpg-sign option.

Signed-off-by: Brandon Richardson <brandon1024.br@gmail.com>
---

Hi all,

Third and (hopefully) final version. Thanks again Martin for the helpful
comments.

---

 builtin/commit-tree.c    |  8 +++++++-
 t/t7510-signed-commit.sh | 13 +++++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/builtin/commit-tree.c b/builtin/commit-tree.c
index 9ec36a82b..298e499ac 100644
--- a/builtin/commit-tree.c
+++ b/builtin/commit-tree.c
@@ -66,7 +66,13 @@ int cmd_commit_tree(int argc, const char **argv, const char *prefix)
 			continue;
 		}
 
-		if (skip_prefix(arg, "-S", &sign_commit))
+		if(!strcmp(arg, "--gpg-sign")) {
+		    sign_commit = "";
+		    continue;
+		}
+
+		if (skip_prefix(arg, "-S", &sign_commit) ||
+			skip_prefix(arg, "--gpg-sign=", &sign_commit))
 			continue;
 
 		if (!strcmp(arg, "--no-gpg-sign")) {
diff --git a/t/t7510-signed-commit.sh b/t/t7510-signed-commit.sh
index 86d3f93fa..095d4b254 100755
--- a/t/t7510-signed-commit.sh
+++ b/t/t7510-signed-commit.sh
@@ -51,13 +51,22 @@ test_expect_success GPG 'create signed commits' '
 	# commit.gpgsign is still on but this must not be signed
 	git tag ninth-unsigned $(echo 9 | git commit-tree HEAD^{tree}) &&
 	# explicit -S of course must sign.
-	git tag tenth-signed $(echo 9 | git commit-tree -S HEAD^{tree})
+	git tag tenth-signed $(echo 10 | git commit-tree -S HEAD^{tree}) &&
+
+	# --gpg-sign[=<key-id>] must sign.
+	echo 11 >file && test_tick && git commit -S -a -m "eleventh signed" &&
+	git tag eleventh-signed &&
+	git commit-tree --gpg-sign -m "twelfth signed" HEAD^{tree} &&
+	git tag twelfth-signed &&
+    git commit-tree --gpg-sign=B7227189 -m "thirteenth signed" HEAD^{tree} &&
+    git tag thirteenth-signed
 '
 
 test_expect_success GPG 'verify and show signatures' '
 	(
 		for commit in initial second merge fourth-signed \
-			fifth-signed sixth-signed seventh-signed tenth-signed
+			fifth-signed sixth-signed seventh-signed tenth-signed \
+			eleventh-signed twelfth-signed thirteenth-signed
 		do
 			git verify-commit $commit &&
 			git show --pretty=short --show-signature $commit >actual &&
-- 
2.20.1