diff -r 6c86c673dde6 -r 8792ac090e3b hgext/histedit.py
--- a/hgext/histedit.py	Tue Oct 14 13:23:52 2014 -0700
+++ b/hgext/histedit.py	Tue Oct 14 13:25:13 2014 -0700
@@ -738,7 +738,7 @@
     When keep is false, the specified set can't have children."""
     ctxs = list(repo.set('%n::%n', old, new))
     if ctxs and not keep:
-        if (not obsolete._enabled and
+        if (not obsolete.isenabled(repo, obsolete.allowunstableopt) and
             repo.revs('(%ld::) - (%ld)', ctxs, ctxs)):
             raise util.Abort(_('cannot edit history that would orphan nodes'))
         if repo.revs('(%ld) and merge()', ctxs):