# HG changeset patch
# User Tony Tung <tonytung@merly.org>
# Date 1462227736 25200
# Node ID e2178f7d17c01fcd5a60b7c2a3f016f1d464c8cf
# Parent  4a65c9c6cd3fdd8e56a366dd16a8bc138f2e0ad6
manifest: improve filesnotin performance by using lazymanifest diff

lazymanifests can compute diffs significantly faster than taking the set
of two manifests and calculating the delta.

when running hg diff --git -c . on Facebook's big repo, this reduces the
run time from 2.1s to 1.5s.

diff -r 4a65c9c6cd3f -r e2178f7d17c0 mercurial/manifest.py
--- a/mercurial/manifest.py	Tue Apr 19 11:00:15 2016 +0100
+++ b/mercurial/manifest.py	Mon May 02 15:22:16 2016 -0700
@@ -211,8 +211,10 @@
 
     def filesnotin(self, m2):
         '''Set of files in this manifest that are not in the other'''
-        files = set(self)
-        files.difference_update(m2)
+        diff = self.diff(m2)
+        files = set(filepath
+                    for filepath, hashflags in diff.iteritems()
+                    if hashflags[1][0] is None)
         return files
 
     @propertycache