static L<File> logFileWithEarlierParts(File file) {
  S name = file.getName() + ".part";
  try {
    new Matches m;
    new TreeMap<Int, File> map;
    for (File p : listFiles(file.getParent())) pcall {
      S n = p.getName();
      if (startsWith(n, name, m))
        map.put(parseFirstInt(m.rest()), p);
    }
    ret concatLists(valuesList(map), file);
  } catch print e {
    ret ll(file);
  }
}