--- a/mercurial/unionrepo.py	Tue Jan 10 06:59:49 2017 +0800
+++ b/mercurial/unionrepo.py	Thu Jan 05 17:16:07 2017 +0000
@@ -93,7 +93,7 @@
         return mdiff.textdiff(self.revision(self.node(rev1)),
                               self.revision(self.node(rev2)))
 
-    def revision(self, nodeorrev):
+    def revision(self, nodeorrev, raw=False):
         """return an uncompressed revision of a given node or revision
         number.
         """