[PATCH 1 of 2] revset: make wdir() work with parent '^' operator(issue4905)

[Pulkit Goyal]

# HG changeset patch
# User Pulkit Goyal <7895pulkit at gmail.com>
# Date 1487801796 -19800
#      Thu Feb 23 03:46:36 2017 +0530
# Node ID e86b701628b33640c537e7377bbee8b69f22e390
# Parent  4572027bbe6795e66758120375f647c1c1804195
revset: make wdir() work with parent '^' operator(issue4905)

Before this patch, running `hg log -r 'wdir()^'` returns error.

diff -r 4572027bbe67 -r e86b701628b3 mercurial/revset.py
--- a/mercurial/revset.py	Wed Feb 22 18:33:00 2017 +0530
+++ b/mercurial/revset.py	Thu Feb 23 03:46:36 2017 +0530
@@ -1399,7 +1399,10 @@
     ps = set()
     cl = repo.changelog
     for r in getset(repo, fullreposet(repo), x):
-        ps.add(cl.parentrevs(r)[0])
+        if r == node.wdirrev:
+            ps.add(subset.last())
+        else:
+            ps.add(cl.parentrevs(r)[0])
     ps -= set([node.nullrev])
     # XXX we should turn this into a baseset instead of a set, smartset may do
     # some optimizations from the fact this is a baseset.
diff -r 4572027bbe67 -r e86b701628b3 tests/test-revset.t
--- a/tests/test-revset.t	Wed Feb 22 18:33:00 2017 +0530
+++ b/tests/test-revset.t	Thu Feb 23 03:46:36 2017 +0530
@@ -1221,6 +1221,8 @@
 Test working-directory revision
   $ hg debugrevspec 'wdir()'
   2147483647
+  $ hg debugrevspec 'wdir()^'
+  9
   $ hg debugrevspec 'tip or wdir()'
   9
   2147483647