mercurial/pycompat.py

--- a/mercurial/pycompat.py	Wed Apr 06 22:35:52 2016 +0000
+++ b/mercurial/pycompat.py	Wed Apr 06 20:31:31 2016 +0000
@@ -11,6 +11,13 @@
 from __future__ import absolute_import
 
 try:
+    import cStringIO as io
+    stringio = io.StringIO
+except ImportError:
+    import io
+    stringio = io.StringIO
+
+try:
     import Queue as _queue
     _queue.Queue
 except ImportError: