getbundle: add a ``cg`` boolean argument to control changegroup inclusion The ``getbundle`` function was initially design to return a changegroup bundle. However, bundle2 allows transmitting a wide range of data. Some bundle2 requests may not include a changegroup at all. Before this changeset, the client would request a changegroup for ``heads=[nullid]`` and receive an empty changegroup. We introduce an official boolean parameter, ``cg``, that can be set to false to disable changegroup generation on getbundle. A new bundle2 capability is introduced to let the client know.

--- a/mercurial/wireproto.py	Thu May 22 17:20:52 2014 -0700
+++ b/mercurial/wireproto.py	Sat May 31 16:48:29 2014 -0700
@@ -203,7 +203,8 @@
 gboptsmap = {'heads':  'nodes',
              'common': 'nodes',
              'bundlecaps': 'csv',
-             'listkeys': 'csv'}
+             'listkeys': 'csv',
+             'cg': 'boolean'}
 
 # client side