--- a/mercurial/demandimport.py	Mon Feb 15 16:49:52 2016 -0800
+++ b/mercurial/demandimport.py	Sat Feb 06 19:09:10 2016 +0900
@@ -174,7 +174,12 @@
             """
             symbol = getattr(mod, attr, nothing)
             if symbol is nothing:
-                symbol = _demandmod(attr, mod.__dict__, locals, level=1)
+                mn = '%s.%s' % (mod.__name__, attr)
+                if mn in ignore:
+                    importfunc = _origimport
+                else:
+                    importfunc = _demandmod
+                symbol = importfunc(attr, mod.__dict__, locals, level=1)
                 setattr(mod, attr, symbol)
 
             # Record the importing module references this symbol so we can