--- a/mercurial/manifest.py	Fri Aug 05 11:19:22 2016 -0400
+++ b/mercurial/manifest.py	Fri Aug 05 13:08:11 2016 -0400
@@ -913,7 +913,7 @@
         self._usemanifestv2 = usemanifestv2
         indexfile = "00manifest.i"
         if dir:
-            assert self._treeondisk
+            assert self._treeondisk, 'opts is %r' % opts
             if not dir.endswith('/'):
                 dir = dir + '/'
             indexfile = "meta/" + dir + "00manifest.i"