diff -r 980aee54fd70 -r d474b3b44d4f mercurial/bundle2.py
--- a/mercurial/bundle2.py	Sun Jul 08 19:34:11 2018 +0900
+++ b/mercurial/bundle2.py	Sun Jul 08 19:24:18 2018 +0900
@@ -628,9 +628,10 @@
     def addparam(self, name, value=None):
         """add a stream level parameter"""
         if not name:
-            raise ValueError(r'empty parameter name')
+            raise error.ProgrammingError(b'empty parameter name')
         if name[0:1] not in pycompat.bytestr(string.ascii_letters):
-            raise ValueError(r'non letter first character: %s' % name)
+            raise error.ProgrammingError(b'non letter first character: %s'
+                                         % name)
         self._params.append((name, value))
 
     def addpart(self, part):