bundle2: return a bundle20 object from exchanges.unbundle

When a bundle2 is pushed we return a bundle instead of an integer. We use to
return a binary stream. We now return a `bundle20` bundler to make the life of
wireprotocol implementation simpler.

mercurial/exchange.py

@@ -694,10 +694,8 b' def unbundle(repo, cg, heads, source, ur'
         # push can proceed
         if util.safehasattr(cg, 'params'):
             tr = repo.transaction('unbundle')
-            ret = bundle2.processbundle(repo, cg, lambda: tr)
+            r = bundle2.processbundle(repo, cg, lambda: tr).reply
             tr.close()
-            stream = util.chunkbuffer(ret.reply.getchunks())
-            r = bundle2.unbundle20(repo.ui, stream)
         else:
             r = changegroup.addchangegroup(repo, cg, source, url)
     finally:

mercurial/localrepo.py

@@ -124,7 +124,14 b' class localpeer(peer.peerrepository):'
         This function handles the repo locking itself."""
         try:
             cg = exchange.readbundle(self.ui, cg, None)
-            return exchange.unbundle(self._repo, cg, heads, 'push', url)
+            ret = exchange.unbundle(self._repo, cg, heads, 'push', url)
+            if util.safehasattr(ret, 'getchunks'):
+                # This is a bundle20 object, turn it into an unbundler.
+                # This little dance should be dropped eventually when the API
+                # is finally improved.
+                stream = util.chunkbuffer(ret.getchunks())
+                ret = bundle2.unbundle20(self.ui, stream)
+            return ret
         except exchange.PushRaced, exc:
             raise error.ResponseError(_('push failed:'), exc.message)