# HG changeset patch
# User Martin von Zweigbergk <martinvonz@google.com>
# Date 1414777296 25200
# Node ID c23c03605c59556910e643a36dd4278f0143bd87
# Parent  0b7853f969ac69b9db735778389b62184a65c48c
revset: don't recreate matcher for every revision

The matcher variable 'm' in checkstatus() is reset to None on each
call, so the caching of the matcher no longer happens as it was
intended. This seems to be a regression in ed7b674824a3 (revset: added
lazyset implementation to checkstatus, 2014-01-03).

Fix by moving the cached matcher into the enclosing function so it's
actually cached across calls. This speeds up

  hg log -r 'modifies(mercurial/context.py)' >/dev/null

from 7.5s to 4s.

Also see similar fix in f2aeff8a87b6 (revset: avoid recalculating
filesets, 2014-10-22).

diff -r 0b7853f969ac -r c23c03605c59 mercurial/revset.py
--- a/mercurial/revset.py	Sat Nov 01 02:43:08 2014 +0900
+++ b/mercurial/revset.py	Fri Oct 31 10:41:36 2014 -0700
@@ -526,14 +526,15 @@
 def checkstatus(repo, subset, pat, field):
     hasset = matchmod.patkind(pat) == 'set'
 
+    mcache = [None]
     def matches(x):
-        m = None
-        fname = None
         c = repo[x]
-        if not m or hasset:
-            m = matchmod.match(repo.root, repo.getcwd(), [pat], ctx=c)
-            if not m.anypats() and len(m.files()) == 1:
-                fname = m.files()[0]
+        if not mcache[0] or hasset:
+            mcache[0] = matchmod.match(repo.root, repo.getcwd(), [pat], ctx=c)
+        m = mcache[0]
+        fname = None
+        if not m.anypats() and len(m.files()) == 1:
+            fname = m.files()[0]
         if fname is not None:
             if fname not in c.files():
                 return False