--- a/mercurial/exchange.py	Mon Apr 21 19:42:51 2014 -0700
+++ b/mercurial/exchange.py	Mon Apr 21 19:43:01 2014 -0700
@@ -584,7 +584,7 @@
     bundle = pullop.remote.getbundle('pull', **kwargs)
     try:
         op = bundle2.processbundle(pullop.repo, bundle, pullop.gettransaction)
-    except KeyError, exc:
+    except UnknownPartError, exc:
         raise util.Abort('missing support for %s' % exc)
     assert len(op.records['changegroup']) == 1
     pullop.cgresult = op.records['changegroup'][0]['return']