private static @Nullable File getCommonBeforeAfterAncestor(@NotNull Change change) {
    FilePath before = getBeforePath(change);
    FilePath after = getAfterPath(change);
    return before == null
           ? Objects.requireNonNull(after).getIOFile()
           : after == null ? before.getIOFile() : FileUtil.findAncestor(before.getIOFile(), after.getIOFile());
  }
private static @Nullable File getCommonBeforeAfterAncestor(@NotNull Change change)