Merge branch 'gc/stash-on-branch-with-multi-level-name'

"git checkout -b branch/with/multi/level/name && git stash" only
recorded the last level component of the branch name, which has
been corrected.

* gc/stash-on-branch-with-multi-level-name:
  stash: strip "refs/heads/" with skip_prefix

builtin/stash.c

@@ -1327,7 +1327,7 @@ static int do_create_stash(const struct pathspec *ps, struct strbuf *stash_msg_b
 
 	branch_ref = resolve_ref_unsafe("HEAD", 0, NULL, &flags);
 	if (flags & REF_ISSYMREF)
-		branch_name = strrchr(branch_ref, '/') + 1;
+		skip_prefix(branch_ref, "refs/heads/", &branch_name);
 	head_short_sha1 = find_unique_abbrev(&head_commit->object.oid,
 					     DEFAULT_ABBREV);
 	strbuf_addf(&msg, "%s: %s ", branch_name, head_short_sha1);

t/t3903-stash.sh

@@ -1045,6 +1045,17 @@ test_expect_success 'create stores correct message' '
 	test_cmp expect actual
 '
 
+test_expect_success 'create when branch name has /' '
+	test_when_finished "git checkout main" &&
+	git checkout -b some/topic &&
+	>foo &&
+	git add foo &&
+	STASH_ID=$(git stash create "create test message") &&
+	echo "On some/topic: create test message" >expect &&
+	git show --pretty=%s -s ${STASH_ID} >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'create with multiple arguments for the message' '
 	>foo &&
 	git add foo &&