push: move push return value in the push object

The return code convey information about the success of changeset push. This is
used by phases to compute the new common set between local and remote. So we
need to move it into the object to extract the phase sync from the god
function.

Note that this information will be used by obsolescence markers too.

mercurial/exchange.py

@@ -35,6 +35,13 b' class pushoperation(object):'
         self.newbranch = newbranch
         # did a local lock get acquired?
         self.locallocked = None
+        # Integer version of the push result
+        # - None means nothing to push
+        # - 0 means HTTP error
+        # - 1 means we pushed and remote head count is unchanged *or*
+        #   we have outgoing changesets but refused to push
+        # - other values as described by addchangegroup()
+        self.ret = None
 
 def push(repo, remote, force=False, revs=None, newbranch=False):
     '''Push outgoing changesets (limited by revs) from a local
@@ -99,7 +106,6 b' def push(repo, remote, force=False, revs'
             if not outgoing.missing:
                 # nothing to push
                 scmutil.nochangesfound(unfi.ui, unfi, outgoing.excluded)
-                ret = None
             else:
                 # something to push
                 if not pushop.force:
@@ -156,14 +162,15 b' def push(repo, remote, force=False, revs'
                         remoteheads = ['force']
                     # ssh: return remote's addchangegroup()
                     # http: return remote's addchangegroup() or 0 for error
-                    ret = pushop.remote.unbundle(cg, remoteheads, 'push')
+                    pushop.ret = pushop.remote.unbundle(cg, remoteheads,
+                                                        'push')
                 else:
                     # we return an integer indicating remote head count
                     # change
-                    ret = pushop.remote.addchangegroup(cg, 'push',
-                                                       pushop.repo.url())
+                    pushop.ret = pushop.remote.addchangegroup(cg, 'push',
+                                                              pushop.repo.url())
 
-            if ret:
+            if pushop.ret:
                 # push succeed, synchronize target of the push
                 cheads = outgoing.missingheads
             elif pushop.revs is None:
@@ -197,7 +204,7 b' def push(repo, remote, force=False, revs'
             remotephases = pushop.remote.listkeys('phases')
             if (pushop.ui.configbool('ui', '_usedassubrepo', False)
                 and remotephases    # server supports phases
-                and ret is None # nothing was pushed
+                and pushop.ret is None # nothing was pushed
                 and remotephases.get('publishing', False)):
                 # When:
                 # - this is a subrepo push
@@ -246,7 +253,7 b' def push(repo, remote, force=False, revs'
             locallock.release()
 
     _pushbookmark(pushop)
-    return ret
+    return pushop.ret
 
 def _localphasemove(pushop, nodes, phase=phases.public):
     """move <nodes> to <phase> in the local source repo"""