diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index 38027b83d9..3b5d58a5fa 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -249,6 +249,8 @@ int cmd_commit_graph(int argc, const char **argv, const char *prefix)
 			     builtin_commit_graph_usage,
 			     PARSE_OPT_STOP_AT_NON_OPTION);
 
+	save_commit_buffer = 0;
+
 	if (argc > 0) {
 		if (!strcmp(argv[0], "read"))
 			return graph_read(argc, argv);