commit-graph: return if there is no git directory

Return early if git directory does not exist. This will protect against
test failures in the upcoming change to BUG in prepare_repo_settings if no
git directory exists.

Signed-off-by: Lessley Dennington <[email protected]>
Reviewed-by: Elijah Newren <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ldennington

commit-graph.c

@@ -632,10 +632,13 @@ static int prepare_commit_graph(struct repository *r)
 	struct object_directory *odb;
 
 	/*
+	 * Early return if there is no git dir or if the commit graph is
+	 * disabled.
+	 *
 	 * This must come before the "already attempted?" check below, because
 	 * we want to disable even an already-loaded graph file.
 	 */
-	if (r->commit_graph_disabled)
+	if (!r->gitdir || r->commit_graph_disabled)
 		return 0;
 
 	if (r->objects->commit_graph_attempted)