diff -r 1dd178277cf5 -r 546fa6576815 mercurial/revset.py
--- a/mercurial/revset.py	Thu Oct 09 09:12:54 2014 -0700
+++ b/mercurial/revset.py	Thu Oct 09 04:24:51 2014 -0700
@@ -2283,12 +2283,7 @@
         """Returns a new object with the union of the two collections.
 
         This is part of the mandatory API for smartset."""
-        kwargs = {}
-        if self.isascending() and other.isascending():
-            kwargs['ascending'] = True
-        if self.isdescending() and other.isdescending():
-            kwargs['ascending'] = False
-        return addset(self, other, **kwargs)
+        return addset(self, other)
 
     def __sub__(self, other):
         """Returns a new object with the substraction of the two collections.