diff -r a2c08adbb86e -r 9a49feb408f3 mercurial/revset.py
--- a/mercurial/revset.py	Wed Feb 12 01:00:51 2014 +0100
+++ b/mercurial/revset.py	Thu Jan 30 17:46:08 2014 -0800
@@ -1202,7 +1202,7 @@
     # i18n: "public" is a keyword
     getargs(x, 0, 0, _("public takes no arguments"))
     pc = repo._phasecache
-    return baseset([r for r in subset if pc.phase(repo, r) == phases.public])
+    return lazyset(subset, lambda r: pc.phase(repo, r) == phases.public)
 
 def remote(repo, subset, x):
     """``remote([id [,path]])``