Retry rename on lock induced failures (#16435)

* Retry rename on lock induced failures

Due to external locking on Windows it is possible for an
os.Rename to fail if the files or directories are being
used elsewhere.

This PR simply suggests retrying the rename again similar
to how we handle the os.Remove problems.

Fix #16427

Signed-off-by: Andrew Thornton <art27@cantab.net>

* resolve CI fail

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

modules/util/remove.go

@@ -33,7 +33,7 @@ func Remove(name string) error {
 	return err
 }
 
-// RemoveAll removes the named file or (empty) directory with at most 5 attempts.Remove
+// RemoveAll removes the named file or (empty) directory with at most 5 attempts.
 func RemoveAll(name string) error {
 	var err error
 	for i := 0; i < 5; i++ {
@@ -55,3 +55,30 @@ func RemoveAll(name string) error {
 	}
 	return err
 }
+
+// Rename renames (moves) oldpath to newpath with at most 5 attempts.
+func Rename(oldpath, newpath string) error {
+	var err error
+	for i := 0; i < 5; i++ {
+		err = os.Rename(oldpath, newpath)
+		if err == nil {
+			break
+		}
+		unwrapped := err.(*os.PathError).Err
+		if unwrapped == syscall.EBUSY || unwrapped == syscall.ENOTEMPTY || unwrapped == syscall.EPERM || unwrapped == syscall.EMFILE || unwrapped == syscall.ENFILE {
+			// try again
+			<-time.After(100 * time.Millisecond)
+			continue
+		}
+
+		if i == 0 && os.IsNotExist(err) {
+			return err
+		}
+
+		if unwrapped == syscall.ENOENT {
+			// it's already gone
+			return nil
+		}
+	}
+	return err
+}