--- a/mercurial/revlog.py	Wed Feb 20 11:49:06 2019 +0100
+++ b/mercurial/revlog.py	Wed Jan 16 16:19:26 2019 +0100
@@ -1121,6 +1121,8 @@
                 return self.index.headrevs()
             except AttributeError:
                 return self._headrevs()
+        if rustext is not None:
+            return rustext.dagop.headrevs(self.index, revs)
         return dagop.headrevs(revs, self._uncheckedparentrevs)
 
     def computephases(self, roots):