diff -r d702f0d26c6a -r 48d18ba05480 hgext/obsolete.py
--- a/hgext/obsolete.py	Tue Aug 07 16:02:50 2012 +0200
+++ b/hgext/obsolete.py	Tue Aug 07 18:17:13 2012 +0200
@@ -557,6 +557,40 @@
             newer.add(())
     return sorted(newer)
 
+def createmarkers(repo, relations, metadata=None, flag=0):
+    """Add obsolete markers between changeset in a repo
+
+    <relations> must be an iterable of (<old>, (<new>, ...)) tuple.
+    `old` and `news` are changectx.
+
+    Current user and date are used except if specified otherwise in the
+    metadata attribute.
+
+    /!\ assume the repo have been locked byt the user /!\
+    """
+    # prepare metadata
+    if metadata is None:
+        metadata = {}
+    if 'date' not in metadata:
+        metadata['date'] = '%i %i' % util.makedate()
+    if 'user' not in metadata:
+        metadata['user'] = repo.ui.username()
+    # check future marker
+    tr = repo.transaction('add-obsolescence-marker')
+    try:
+        for prec, sucs in relations:
+            if not prec.mutable():
+                raise util.Abort("Cannot obsolete immutable changeset: %s" % prec)
+            nprec = prec.node()
+            nsucs = tuple(s.node() for s in sucs)
+            if nprec in nsucs:
+                raise util.Abort("Changeset %s cannot obsolete himself" % prec)
+            repo.obsstore.create(tr, nprec, nsucs, flag, metadata)
+            repo._clearobsoletecache()
+        tr.close()
+    finally:
+        tr.release()
+
 @eh.reposetup
 def _repoobsutilsetup(ui, repo):
     if not repo.local():
@@ -567,31 +601,11 @@
         # XXX kill me
         def addobsolete(self, sub, obj):
             """Add a relation marking that node <sub> is a new version of <obj>"""
-            assert sub != obj
-            if not repo[obj].phase():
-                if sub is None:
-                    self.ui.warn(
-                        _("trying to kill immutable changeset %(obj)s\n")
-                        % {'obj': short(obj)})
-                if sub is not None:
-                    self.ui.warn(
-                        _("%(sub)s try to obsolete immutable changeset %(obj)s\n")
-                        % {'sub': short(sub), 'obj': short(obj)})
+            prec = repo[obj]
+            sucs = (sub == nullid) and [] or [repo[sub]]
             lock = self.lock()
             try:
-                tr = self.transaction('add-obsolete')
-                try:
-                    meta = {
-                        'date':  '%i %i' % util.makedate(),
-                        'user': ui.username(),
-                        }
-                    subs = (sub == nullid) and [] or [sub]
-                    mid = self.obsstore.create(tr, obj, subs, 0, meta)
-                    tr.close()
-                    self._clearobsoletecache()
-                    return mid
-                finally:
-                    tr.release()
+                createmarkers(self, [(prec, sucs)])
             finally:
                 lock.release()