dropbox: fix error moving just created objects - fixes #8881

The bisync tests have been failing as Dropbox is failing to move just
created objects. This seems to be caused by an eventual consistency
problem so this attempts to fix it by retrying the specific error.

backend/dropbox/dropbox.go

@@ -1330,6 +1330,16 @@ func (f *Fs) Move(ctx context.Context, src fs.Object, remote string) (fs.Object,
 	var result *files.RelocationResult
 	err = f.pacer.Call(func() (bool, error) {
 		result, err = f.srv.MoveV2(&arg)
+		switch e := err.(type) {
+		case files.MoveV2APIError:
+			// There seems to be a bit of eventual consistency here which causes this to
+			// fail on just created objects
+			// See: https://github.com/rclone/rclone/issues/8881
+			if e.EndpointError != nil && e.EndpointError.FromLookup != nil && e.EndpointError.FromLookup.Tag == files.LookupErrorNotFound {
+				fs.Debugf(srcObj, "Retrying move on %v error", err)
+				return true, err
+			}
+		}
 		return shouldRetry(ctx, err)
 	})
 	if err != nil {