private @NotNull List<Change> executeDiff(@NotNull FilePath path, @Nullable HgFileRevision rev1, @Nullable HgFileRevision rev2) {
    VirtualFile root = VcsUtil.getVcsRootFor(myProject, path);
    LOG.assertTrue(root != null, "Repository is null for " + path);

    return HgUtil
      .getDiff(myProject, root, path, rev1 != null ? rev1.getRevisionNumber() : null, rev2 != null ? rev2.getRevisionNumber() : null);
  }
private @NotNull List<Change> executeDiff(@NotNull FilePath path, @Nullable HgFileRevision rev1, @Nullable HgFileRevision rev2)