diff -r 90f86ad3d4ff -r 73f394f4affc mercurial/error.py
--- a/mercurial/error.py	Wed Oct 01 23:40:23 2014 -0500
+++ b/mercurial/error.py	Wed Oct 15 03:22:47 2014 -0700
@@ -102,6 +102,7 @@
 class BundleValueError(ValueError):
     """error raised when bundle2 cannot be processed"""
 
+class UnsupportedPartError(BundleValueError):
     def __init__(self, parttype=None, params=()):
         self.parttype = parttype
         self.params = params