private @NotNull @NonNls String constructLightFilePath() {
      if (originalFilePath != null) {
        return originalFilePath;
      }

      String name = fileName;
      if (name == null) {
        FileType fileType = guessFileType();
        name = "diff." + StringUtil.defaultIfEmpty(fileType != null ? fileType.getDefaultExtension() : null, "txt");
      }
      return name;
    }
private @NotNull @NonNls String constructLightFilePath()