[PATCH 7 of 7] checkheads: simplify the code around obsolescence post-processing

[Pierre-Yves David]

# HG changeset patch
# User Pierre-Yves David <pierre-yves.david at octobus.net>
# Date 1496028210 -7200
#      Mon May 29 05:23:30 2017 +0200
# Node ID 54ef0920630de5f0c3c666dbb30a73b1adcb91ec
# Parent  e3c199932c9c84037a05ffe817838a5a4bd6f5a8
# EXP-Topic pushrace
# Available At https://www.mercurial-scm.org/repo/users/marmoute/mercurial/
#              hg pull https://www.mercurial-scm.org/repo/users/marmoute/mercurial/ -r 54ef0920630d
checkheads: simplify the code around obsolescence post-processing

The 'discardedheads' return become unused and the relationship between newheads
and newhs can be clarified. Our next goal here is to be able to extract the
_postprocessobsolete call outside of the loop.

We keep returning the 'discardedheads' because we'll start using it again soon
in this series.

diff --git a/mercurial/discovery.py b/mercurial/discovery.py
--- a/mercurial/discovery.py
+++ b/mercurial/discovery.py
@@ -347,13 +347,10 @@ def checkheads(pushop):
             oldhs = set(remoteheads)
         oldhs.update(unsyncedheads)
         dhs = None # delta heads, the new heads on branch
-        if not repo.obsstore:
-            discardedheads = set()
-            newhs = set(newheads)
-        else:
-            newhs, discardedheads = _postprocessobsolete(pushop,
-                                                         allfuturecommon,
-                                                         newheads)
+        if repo.obsstore:
+            result = _postprocessobsolete(pushop, allfuturecommon, newheads)
+            newheads = sorted(result[0])
+        newhs = set(newheads)
         newhs.update(unsyncedheads)
         if unsyncedheads:
             if None in unsyncedheads: