# HG changeset patch
# User Lucas Moscovicz <lmoscovicz@fb.com>
# Date 1391472168 28800
# Node ID ad2f1512eaa618c7f1edf21a6c563c18e5bee43b
# Parent  92f6f2db3cf475e7a1f20f7e1a78cf41b49985b5
revset: added lazyset implementation to date revset

Performance Benchmarking:

$ time hg log -qr "first(date(05/03/2005))"
0:9117c6561b0b

real  0m3.157s
user  0m2.994s
sys 0m0.087s

$ time ./hg log -qr "first(date(05/03/2005))"
0:9117c6561b0b

real  0m0.509s
user  0m0.289s
sys 0m0.070s

diff -r 92f6f2db3cf4 -r ad2f1512eaa6 mercurial/revset.py
--- a/mercurial/revset.py	Wed Jan 29 09:22:31 2014 -0800
+++ b/mercurial/revset.py	Mon Feb 03 16:02:48 2014 -0800
@@ -582,7 +582,7 @@
     # i18n: "date" is a keyword
     ds = getstring(x, _("date requires a string"))
     dm = util.matchdate(ds)
-    return baseset([r for r in subset if dm(repo[r].date()[0])])
+    return lazyset(subset, lambda x: dm(repo[x].date()[0]))
 
 def desc(repo, subset, x):
     """``desc(string)``