Change type of extraRecipients to a list....

master.o3d/master.cfg

 # -*- python -*-
 # ex: set syntax=python:
 
 # Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This is the buildmaster config file for the 'chromium' bot. It must
 # be installed as 'master.cfg' in your buildmaster's base directory
 # (although the filename can be changed with the --basedir option to
@@ skipping 453 matching lines @@
   exclusions = {}
   forgiving_steps = ['update scripts', 'update', 'svnkill', 'taskkill',
                      'archived build']
   c['status'].append(gatekeeper.GateKeeper(
       fromaddr=ActiveMaster.from_address,
       categories_steps=categories_steps,
       exclusions=exclusions,
       relayhost=config.Master.smtp,
       subject='buildbot %(result)s in %(projectName)s on %(builder)s, '
               'revision %(revision)s',
-      extraRecipients=tuple(ActiveMaster.tree_closing_notification_recipients),
+      extraRecipients=ActiveMaster.tree_closing_notification_recipients,
       tree_status_url=ActiveMaster.tree_status_url,
       lookup='google.com',
       forgiving_steps=forgiving_steps))
 
 if GOOD_REVISIONS:
   import goodrevisions
   # This is the list of builders with their respective list of critical steps
   # that all need to succeed to mark a revision as successful. A single failure
   # in any of the steps of any of the builders will mark the revision as failed.
   good_revision_steps = {
@@ skipping 44 matching lines @@
 c['projectURL'] = config.Master.project_url
 
 # the 'buildbotURL' string should point to the location where the buildbot's
 # internal web server (usually the html.Waterfall page) is visible. This
 # typically uses the port number set in the Waterfall 'status' entry, but
 # with an externally-visible host name which the buildbot cannot figure out
 # without some help.
 
 c['buildbotURL'] = 'http://build.chromium.org/buildbot/o3d/'