diff -r 33e1fd2aeb3c -r 95514b58709d mercurial/context.py
--- a/mercurial/context.py	Thu Oct 14 21:36:00 2010 +0200
+++ b/mercurial/context.py	Thu Oct 14 22:47:50 2010 +0200
@@ -357,10 +357,11 @@
 
         returns True if different than fctx.
         """
-        if not self._repo._encodefilterpats and self.size() != fctx.size():
-            return True
+        if (fctx._filerev is None and self._repo._encodefilterpats
+            or self.size() == fctx.size()):
+            return self._filelog.cmp(self._filenode, fctx.data())
 
-        return self._filelog.cmp(self._filenode, fctx.data())
+        return True
 
     def renamed(self):
         """check if file was actually renamed in this changeset revision