bundle: make combinechangegroupresults() take a bundleoperation

Both callers have a bundleoperation. Passing it in lets us share a bit
more code.

mercurial/bundle2.py

@@ -1478,8 +1478,10 b' def writebundle(ui, cg, filename, bundle'
     # in case of sshrepo because we don't know the end of the stream
     return changegroup.writechunks(ui, chunkiter, filename, vfs=vfs)
 
-def combinechangegroupresults(results):
+def combinechangegroupresults(op):
     """logic to combine 0 or more addchangegroup results into one"""
+    results = [r.get('return', 0)
+               for r in op.records['changegroup']]
     changedheads = 0
     result = 1
     for ret in results:

mercurial/commands.py

@@ -5214,9 +5214,7 b' def unbundle(ui, repo, fname1, *fnames, '
                             hint=_("see https://mercurial-scm.org/"
                                    "wiki/BundleFeature for more "
                                    "information"))
-                changes = [r.get('return', 0)
-                           for r in op.records['changegroup']]
-                modheads = bundle2.combinechangegroupresults(changes)
+                modheads = bundle2.combinechangegroupresults(op)
             else:
                 txnname = 'unbundle\n%s' % util.hidepassword(url)
                 with repo.transaction(txnname) as tr:

mercurial/exchange.py

@@ -1397,8 +1397,7 b' def _pullbundle2(pullop):'
         raise error.Abort(_('missing support for %s') % exc)
 
     if pullop.fetch:
-        results = [cg['return'] for cg in op.records['changegroup']]
-        pullop.cgresult = bundle2.combinechangegroupresults(results)
+        pullop.cgresult = bundle2.combinechangegroupresults(op)
 
     # processing phases change
     for namespace, value in op.records['listkeys']: