# File lib/grit_adapter/git_layer_grit.rb, line 171
      def revert(path, sha1, sha2, ref)
        patch = path ?
          repo.diff(sha2, sha1, path).first.diff : repo.diff(sha2, sha1).map { |d| d.diff }.join("\n")
        @git.apply_patch({}, ref, patch)
      end