1 files changed, 3 insertions, 2 deletions
diff --git a/shallow.c b/shallow.c
index dbd9f5a..4d90eda 100644
--- a/shallow.c
+++ b/shallow.c
@@ -56,7 +56,7 @@ struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
 			if (i < heads->nr) {
 				commit = (struct commit *)
 					deref_tag(heads->objects[i++].item, NULL, 0);
-				if (commit->object.type != OBJ_COMMIT) {
+				if (!commit || commit->object.type != OBJ_COMMIT) {
 					commit = NULL;
 					continue;
 				}
@@ -70,7 +70,8 @@ struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
 				cur_depth = *(int *)commit->util;
 			}
 		}
-		parse_commit(commit);
+		if (parse_commit(commit))
+			die("invalid commit");
 		commit->object.flags |= not_shallow_flag;
 		cur_depth++;
 		for (p = commit->parents, commit = NULL; p; p = p->next) {