diff -r 9eeca021a803 -r 4e554a7df1e9 mercurial/demandimport.py
--- a/mercurial/demandimport.py	Sat Nov 14 17:14:14 2015 -0800
+++ b/mercurial/demandimport.py	Sat Nov 21 22:28:01 2015 -0800
@@ -245,6 +245,10 @@
 
 def enable():
     "enable global demand-loading of modules"
+    # PyPy doesn't work with demand import.
+    if '__pypy__' in sys.builtin_module_names:
+        return
+
     if os.environ.get('HGDEMANDIMPORT') != 'disable':
         builtins.__import__ = _demandimport