changeset 22863:a1a02b516cca

baseset: empty or one-element sets are ascending and descending

The empty set is full of interesting properties. In the ordering case, the one
element set is too.

--- a/mercurial/revset.py	Tue Oct 07 01:33:05 2014 -0700
+++ b/mercurial/revset.py	Thu Oct 09 04:12:20 2014 -0700
@@ -2368,12 +2368,16 @@
         """Returns True if the collection is ascending order, False if not.
 
         This is part of the mandatory API for smartset."""
+        if len(self) <= 1:
+            return True
         return self._ascending is not None and self._ascending
 
     def isdescending(self):
         """Returns True if the collection is descending order, False if not.
 
         This is part of the mandatory API for smartset."""
+        if len(self) <= 1:
+            return True
         return self._ascending is not None and not self._ascending
 
     def first(self):