--- a/mercurial/filelog.py	Fri Sep 28 11:00:20 2018 -0700
+++ b/mercurial/filelog.py	Fri Sep 28 11:03:17 2018 -0700
@@ -49,7 +49,8 @@
         return self._revlog.node(rev)
 
     def lookup(self, node):
-        return self._revlog.lookup(node)
+        return storageutil.fileidlookup(self._revlog, node,
+                                        self._revlog.indexfile)
 
     def linkrev(self, rev):
         return self._revlog.linkrev(rev)