private static boolean isRequestValid(@Nullable DiffRequest request) {
    if (request instanceof ContentDiffRequest) {
      for (DiffContent content : ((ContentDiffRequest)request).getContents()) {
        // We compare CurrentContentRevision by their FilePath in cache map
        // If file was removed and then created again - we should not reuse request with old invalidated VirtualFile
        if (content instanceof FileContent && !((FileContent)content).getFile().isValid()) return false;
      }
    }
    return true;
  }
private static boolean isRequestValid(@Nullable DiffRequest request)