diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index c1c40b516d..a81a2c76ff 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -711,7 +711,7 @@ int cmd_bisect__helper(int argc, const char **argv, const char *prefix)
 		res = bisect_start(&terms, no_checkout, argv, argc);
 		break;
 	default:
-		return error("BUG: unknown subcommand '%d'", cmdmode);
+		BUG("unknown subcommand %d", (int)cmdmode);
 	}
 	free_terms(&terms);