branch: delete symref branch, not its target

If a branch that is to be deleted happens to be a symref to another
branch, the current code removes the targeted branch instead of the
one it was called for.

Change this surprising behaviour and delete the symref branch
instead.
Signed-off-by: NRene Scharfe <rene.scharfe@lsrfire.ath.cx>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

builtin/branch.c

@@ -239,7 +239,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 			continue;
 		}
 
-		if (delete_ref(name, sha1, 0)) {
+		if (delete_ref(name, sha1, REF_NODEREF)) {
 			error(remote_branch
 			      ? _("Error deleting remote branch '%s'")
 			      : _("Error deleting branch '%s'"),

t/t3200-branch.sh

@@ -262,6 +262,17 @@ test_expect_success 'config information was renamed, too' \
 	"test $(git config branch.s.dummy) = Hello &&
 	 test_must_fail git config branch.s/s/dummy"
 
+test_expect_success 'deleting a symref' '
+	git branch target &&
+	git symbolic-ref refs/heads/symref refs/heads/target &&
+	sha1=$(git rev-parse symref | cut -c 1-7) &&
+	echo "Deleted branch symref (was $sha1)." >expect &&
+	git branch -d symref >actual &&
+	test_path_is_file .git/refs/heads/target &&
+	test_path_is_missing .git/refs/heads/symref &&
+	test_i18ncmp expect actual
+'
+
 test_expect_success 'renaming a symref is not allowed' \
 '
 	git symbolic-ref refs/heads/master2 refs/heads/master &&