[PATCH 3 of 3] changegroup: switch to manifestctx.readstoragenewnodes() (issue5367)

[Gregory Szorc]

# HG changeset patch
# User Gregory Szorc <gregory.szorc at gmail.com>
# Date 1489519968 25200
#      Tue Mar 14 12:32:48 2017 -0700
# Node ID 58091ccc1d551152d4c135db1a394c1763bb24c4
# Parent  c130f8c7496a823c92d3d71880e5beb9fb60c0f7
changegroup: switch to manifestctx.readstoragenewnodes() (issue5367)

readdelta() could return a delta against an empty manifest, which
would result in scanning every single file in the manifest.

We now have an API for returning a more minimal delta. So we
switch to it.

diff --git a/mercurial/changegroup.py b/mercurial/changegroup.py
--- a/mercurial/changegroup.py
+++ b/mercurial/changegroup.py
@@ -338,9 +338,9 @@ class cg1unpacker(object):
                     # validate incoming csets have their manifests
                     for cset in xrange(clstart, clend):
                         mfnode = cl.changelogrevision(cset).manifest
-                        mfest = ml[mfnode].readdelta()
-                        # store file nodes we must see
-                        for f, n in mfest.iteritems():
+                        # Find new nodes referenced by the manifest so we
+                        # can verify they exist later.
+                        for f, n in ml[mfnode].readstoragenewnodes():
                             needfiles.setdefault(f, set()).add(n)
 
                 # process the files