diff --git a/builtin/blame.c b/builtin/blame.c
index 5a67c20..01956c8 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -2050,14 +2050,8 @@
 		return 0;
 	}
 
-	switch (userdiff_config(var, value)) {
-	case 0:
-		break;
-	case -1:
+	if (userdiff_config(var, value) < 0)
 		return -1;
-	default:
-		return 0;
-	}
 
 	return git_default_config(var, value, cb);
 }