1 files changed, 11 insertions, 5 deletions
diff --git a/commit-graph.h b/commit-graph.h
index 7dfb8c896f..869717ca19 100644
--- a/commit-graph.h
+++ b/commit-graph.h
@@ -65,12 +65,18 @@ struct commit_graph *parse_commit_graph(void *graph_map, int fd,
  */
 int generation_numbers_enabled(struct repository *r);
 
-void write_commit_graph_reachable(const char *obj_dir, int append,
+/*
+ * The write_commit_graph* methods return zero on success
+ * and a negative value on failure. Note that if the repository
+ * is not compatible with the commit-graph feature, then the
+ * methods will return 0 without writing a commit-graph.
+ */
+int write_commit_graph_reachable(const char *obj_dir, int append,
 				  int report_progress);
-void write_commit_graph(const char *obj_dir,
-			struct string_list *pack_indexes,
-			struct string_list *commit_hex,
-			int append, int report_progress);
+int write_commit_graph(const char *obj_dir,
+		       struct string_list *pack_indexes,
+		       struct string_list *commit_hex,
+		       int append, int report_progress);
 
 int verify_commit_graph(struct repository *r, struct commit_graph *g);