mercurial/bundle2.py

--- a/mercurial/bundle2.py	Wed May 28 16:46:58 2014 -0700
+++ b/mercurial/bundle2.py	Wed May 28 15:37:47 2014 -0700
@@ -523,7 +523,7 @@
         if name[0].islower():
             self.ui.debug("ignoring unknown parameter %r\n" % name)
         else:
-            raise KeyError(name)
+            raise error.BundleValueError(params=(name,))
 
 
     def iterparts(self):