[PATCH discussion-starter] context: use unfiltered repo for '.'

[Martin von Zweigbergk]

# HG changeset patch
# User Martin von Zweigbergk <martinvonz at google.com>
# Date 1416514512 28800
#      Thu Nov 20 12:15:12 2014 -0800
# Node ID 0fc2520d2eb615497542d3103eab0c3c7ab25e13
# Parent  e1dbe0b215ae137eec53ceb12440536d570a83d2
context: use unfiltered repo for '.'

There is no reason to read obsolescence markers when doing a plain 'hg
status' without --rev. Use the unfiltered repo when initializing
context._rev to speed things up. This speeds up 'hg status' from
1.342s to 0.080s on my repo with ~110k markers.

diff -r e1dbe0b215ae -r 0fc2520d2eb6 mercurial/context.py
--- a/mercurial/context.py	Mon Feb 02 19:58:41 2015 -0500
+++ b/mercurial/context.py	Thu Nov 20 12:15:12 2014 -0800
@@ -376,10 +376,6 @@
                 return
             if isinstance(changeid, long):
                 changeid = str(changeid)
-            if changeid == '.':
-                self._node = repo.dirstate.p1()
-                self._rev = repo.changelog.rev(self._node)
-                return
             if changeid == 'null':
                 self._node = nullid
                 self._rev = nullrev
@@ -388,6 +384,10 @@
                 self._node = repo.changelog.tip()
                 self._rev = repo.changelog.rev(self._node)
                 return
+            if changeid == '.' or changeid == repo.dirstate.p1():
+                self._node = repo.dirstate.p1()
+                self._rev = repo.unfiltered().changelog.rev(self._node)
+                return
             if len(changeid) == 20:
                 try:
                     self._node = changeid