diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -1912,17 +1912,7 @@ class localrepository(object):
                             self.ui.warn(_('updating %s to public failed!\n')
                                             % newremotehead)
                 self.ui.debug('try to push obsolete markers to remote\n')
-                if (obsolete._enabled and self.obsstore and
-                    'obsolete' in remote.listkeys('namespaces')):
-                    rslts = []
-                    remotedata = self.listkeys('obsolete')
-                    for key in sorted(remotedata, reverse=True):
-                        # reverse sort to ensure we end with dump0
-                        data = remotedata[key]
-                        rslts.append(remote.pushkey('obsolete', key, '', data))
-                    if [r for r in rslts if not r]:
-                        msg = _('failed to push some obsolete markers!\n')
-                        self.ui.warn(msg)
+                obsolete.syncpush(self, remote)
             finally:
                 if lock is not None:
                     lock.release()
diff --git a/mercurial/obsolete.py b/mercurial/obsolete.py
--- a/mercurial/obsolete.py
+++ b/mercurial/obsolete.py
@@ -370,6 +370,22 @@ def pushmarker(repo, key, old, new):
     finally:
         lock.release()
 
+def syncpush(repo, remote):
+    """utility function to push bookmark to a remote
+
+    Exist mostly to allow overridding for experimentation purpose"""
+    if (_enabled and repo.obsstore and
+        'obsolete' in remote.listkeys('namespaces')):
+        rslts = []
+        remotedata = repo.listkeys('obsolete')
+        for key in sorted(remotedata, reverse=True):
+            # reverse sort to ensure we end with dump0
+            data = remotedata[key]
+            rslts.append(remote.pushkey('obsolete', key, '', data))
+        if [r for r in rslts if not r]:
+            msg = _('failed to push some obsolete markers!\n')
+            repo.ui.warn(msg)
+
 def allmarkers(repo):
     """all obsolete markers known in a repository"""
     for markerdata in repo.obsstore: