diff --git a/mercurial/patch.py b/mercurial/patch.py
index 85fc79707cb297f80c243a62ec70a011a41aff42_bWVyY3VyaWFsL3BhdGNoLnB5..0d6b64fbb5ba24f9dc88bdd7baf0068dfeae4953_bWVyY3VyaWFsL3BhdGNoLnB5 100644
--- a/mercurial/patch.py
+++ b/mercurial/patch.py
@@ -16,7 +16,6 @@
 
 from i18n import _
 from node import hex, short
-import cStringIO
 import base85, mdiff, scmutil, util, diffhelpers, copies, encoding, error
 import pathutil