# HG changeset patch
# User Michael O'Connor <moconnor@janestreet.com>
# Date 2015-04-13 13:54:36
# Node ID 2b044925580057148784a819cafa010297127bf5
# Parent  03ee576784e68d9396b6e97a3d150815c414eb0d

discovery: don't compute allfuturecommon when it won't be used

In repos with many changesets, the computation of allfuturecommon
can take a significant amount of time.  Since it's only used if
there's an obsstore, don't compute it otherwise.

diff --git a/mercurial/discovery.py b/mercurial/discovery.py
--- a/mercurial/discovery.py
+++ b/mercurial/discovery.py
@@ -272,9 +272,13 @@ def checkheads(repo, remote, outgoing, r
     # If there are more heads after the push than before, a suitable
     # error message, depending on unsynced status, is displayed.
     error = None
-    allmissing = set(outgoing.missing)
-    allfuturecommon = set(c.node() for c in repo.set('%ld', outgoing.common))
-    allfuturecommon.update(allmissing)
+    # If there is no obsstore, allfuturecommon won't be used, so no
+    # need to compute it.
+    if repo.obsstore:
+        allmissing = set(outgoing.missing)
+        cctx = repo.set('%ld', outgoing.common)
+        allfuturecommon = set(c.node() for c in cctx)
+        allfuturecommon.update(allmissing)
     for branch, heads in sorted(headssum.iteritems()):
         remoteheads, newheads, unsyncedheads = heads
         candidate_newhs = set(newheads)