builtin/clone: introduce `--ref-format=` value flag

Introduce a new `--ref-format` value flag for git-clone(1) that allows
the user to specify the ref format that is to be used for a newly
initialized repository.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index 47eae641f0..fb1b9c686d 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -157,6 +157,23 @@ test_expect_success 'clone --mirror does not repeat tags' '
 
 '
 
+test_expect_success 'clone with files ref format' '
+	test_when_finished "rm -rf ref-storage" &&
+	git clone --ref-format=files --mirror src ref-storage &&
+	echo files >expect &&
+	git -C ref-storage rev-parse --show-ref-format >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'clone with garbage ref format' '
+	cat >expect <<-EOF &&
+	fatal: unknown ref storage format ${SQ}garbage${SQ}
+	EOF
+	test_must_fail git clone --ref-format=garbage --mirror src ref-storage 2>err &&
+	test_cmp expect err &&
+	test_path_is_missing ref-storage
+'
+
 test_expect_success 'clone to destination with trailing /' '
 
 	git clone src target-1/ &&