[PATCH 3 of 7] revset: add stub to handle parentpost operation

[Yuya Nishihara]

# HG changeset patch
# User Yuya Nishihara <yuya at tcha.org>
# Date 1470559732 -32400
#      Sun Aug 07 17:48:52 2016 +0900
# Node ID 9a660e4113cae1f0af3c55056d703659e760ec35
# Parent  4d34f5ba70ec4eb76fd592245adf695e7cd2a805
revset: add stub to handle parentpost operation

All operations will take 'order' flag, but p1() function won't.

diff --git a/mercurial/revset.py b/mercurial/revset.py
--- a/mercurial/revset.py
+++ b/mercurial/revset.py
@@ -1528,6 +1528,9 @@ def p2(repo, subset, x):
     # some optimisations from the fact this is a baseset.
     return subset & ps
 
+def parentpost(repo, subset, x):
+    return p1(repo, subset, x)
+
 @predicate('parents([set])', safe=True)
 def parents(repo, subset, x):
     """
@@ -2307,7 +2310,7 @@ methods = {
     "func": func,
     "ancestor": ancestorspec,
     "parent": parentspec,
-    "parentpost": p1,
+    "parentpost": parentpost,
 }
 
 # Constants for ordering requirement, used in _analyze():