--- a/mercurial/manifest.py	Mon Jul 02 11:14:13 2018 -0700
+++ b/mercurial/manifest.py	Wed Jul 04 12:12:49 2018 -0700
@@ -1348,6 +1348,9 @@
         self._dirmancache.clear()
         self._revlog.clearcaches()
 
+    def rev(self, node):
+        return self._revlog.rev(node)
+
 @interfaceutil.implementer(repository.imanifestrevisionwritable)
 class memmanifestctx(object):
     def __init__(self, manifestlog):