diff --git a/server/repo.go b/server/repo.go
index 5483cc7..c1ed91e 100644
--- a/server/repo.go
+++ b/server/repo.go
@@ -51,7 +51,7 @@ var (
 )
 
 func (ot OpType) String() string {
-	return ot.String()
+	return string(ot)
 }
 
 type Op struct {