diff --git a/sha1_name.c b/sha1_name.c
index 73a915ff1b..9b5d14b4bf 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1263,11 +1263,12 @@ int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
 {
 	char *at;
 	const char *start;
-	int len = interpret_nth_prior_checkout(name, namelen, buf);
+	int len;
 
 	if (!namelen)
 		namelen = strlen(name);
 
+	len = interpret_nth_prior_checkout(name, namelen, buf);
 	if (!len) {
 		return len; /* syntax Ok, not enough switches */
 	} else if (len > 0) {
diff --git a/t/t0100-previous.sh b/t/t0100-previous.sh
index e0a6940232..58c0b7e9b6 100755
--- a/t/t0100-previous.sh
+++ b/t/t0100-previous.sh
@@ -56,5 +56,13 @@ test_expect_success 'merge @{-100} before checking out that many branches yet' '
 	test_must_fail git merge @{-100}
 '
 
+test_expect_success 'log -g @{-1}' '
+	git checkout -b last_branch &&
+	git checkout -b new_branch &&
+	echo "last_branch@{0}" >expect &&
+	git log -g --format=%gd @{-1} >actual &&
+	test_cmp expect actual
+'
+
 test_done