diff --git a/hgext/narrow/narrowbundle2.py b/hgext/narrow/narrowbundle2.py
--- a/hgext/narrow/narrowbundle2.py
+++ b/hgext/narrow/narrowbundle2.py
@@ -51,7 +51,7 @@
     caps[NARROWCAP] = ['v0']
     return caps
 
-def widen_changegroup(repo, diffmatcher, common, cgversion, source):
+def widen_changegroup(repo, diffmatcher, common, cgversion):
     """generates changegroup for widening a narrow clone
 
     repo is the localrepository instance
@@ -59,7 +59,6 @@
     (oldincludes, oldexcludes)'
     common is set of common revs between server and client
     cgversion is the changegroup version to send
-    source is the command which called this codepath
 
     returns changegroup data of the changegroup built or return None if there
     are no common revs
@@ -76,7 +75,7 @@
                                         filematcher=diffmatcher,
                                         fullnodes=commonnodes)
         cgdata = packer.generate(set([nullid]), list(commonnodes), False,
-                                 source, changelog=False)
+                                 'narrow_widen', changelog=False)
 
         return cgdata
 
@@ -110,7 +109,7 @@
     common = set(common or [nullid])
 
     if (oldinclude != include or oldexclude != exclude):
-        cgdata = widen_changegroup(repo, diffmatch, common, version, source)
+        cgdata = widen_changegroup(repo, diffmatch, common, version)
         if cgdata is not None:
             part = bundler.newpart('changegroup', data=cgdata)
             part.addparam('version', version)
@@ -189,7 +188,7 @@
                                             shallow=depth is not None,
                                             ellipsisroots=newellipsis,
                                             fullnodes=newfull)
-            cgdata = packer.generate(common, newvisit, False, source)
+            cgdata = packer.generate(common, newvisit, False, 'narrow_widen')
 
             part = bundler.newpart('changegroup', data=cgdata)
             part.addparam('version', version)
@@ -207,7 +206,7 @@
                                         shallow=depth is not None,
                                         ellipsisroots=ellipsisroots,
                                         fullnodes=relevant_nodes)
-        cgdata = packer.generate(common, visitnodes, False, source)
+        cgdata = packer.generate(common, visitnodes, False, 'narrow_widen')
 
         part = bundler.newpart('changegroup', data=cgdata)
         part.addparam('version', version)