diff --git a/modules/repofiles/update.go b/modules/repofiles/update.go
index 0ce0318da..d7751d50e 100644
--- a/modules/repofiles/update.go
+++ b/modules/repofiles/update.go
@@ -940,10 +940,13 @@ func moveAndAddFiles(oldTreePath, newTreePath string, t *TemporaryUploadReposito
 		if v == "" {
 			continue
 		}
+		//example for v(mode SHA-1 stage file)
+		//100755 d294c88235ac05d3dece028d8a65590f28ec46ac 0       custom/conf/app.ini
 		v = strings.ReplaceAll(v, "0\t", "")
 		tmpArray := strings.Split(v, " ")
 		oldPath := tmpArray[2]
 		newPath := newTreePath + strings.TrimPrefix(oldPath, oldTreePath)
+		// mode 0 means remove file
 		stdIn.WriteString("0 0000000000000000000000000000000000000000\t")
 		stdIn.WriteString(oldPath)
 		stdIn.WriteByte('\000')