Bot update!

scripts/slave/chromium_commands.py

 # Copyright (c) 2012 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.
 
 """A subclass of commands.SVN that allows more flexible error recovery.
 
 This code is only used on the slave but it is living in common/ because it is
 directly imported from buildbot/slave/bot.py."""
 
 import os
@@ skipping 251 matching lines @@
     self.gclient_deps = args.get('gclient_deps')
     self.sourcedata = '%s\n' % self.svnurl
     self.rm_timeout = args.get('rm_timeout', self.timeout)
     self.env = args.get('env')
     self.gclient_nohooks = args.get('gclient_nohooks', False)
     self.env['CHROMIUM_GYP_SYNTAX_CHECK'] = '1'
     self.no_gclient_branch = args.get('no_gclient_branch')
     self.no_gclient_revision = args.get('no_gclient_revision', False)
     self.gclient_transitive = args.get('gclient_transitive')
     self.gclient_jobs = args.get('gclient_jobs')
+    self.do_nothing = False
 
   def start(self):
     """Start the update process.
 
     start() is cut-and-paste from the base class, the block calling
     self.sourcedirIsPatched() and the revert support is the only functional
     difference from base."""
     self.sendStatus({'header': "starting " + self.header + "\n"})
     self.command = None
 
     # self.srcdir is where the VC system should put the sources
     if self.mode == "copy":
       self.srcdir = "source" # hardwired directory name, sorry
     else:
       self.srcdir = self.workdir
     self.sourcedatafile = os.path.join(self.builder.basedir,
                                        self.srcdir,
                                        ".buildbot-sourcedata")
+    self.do_nothing = os.path.isfile(os.path.join(self.builder.basedir,
+                                                  self.srcdir,
+                                                  'update.flag'))
 
-    d = defer.succeed(None)
+    d = defer.succeed(0)
+
+    if self.do_nothing:
+      # If bot update is run, we don't need to run the traditional update step.
+      msg = 'update.flag file found: bot_update has run and checkout is \n'
+      msg += 'already in a consistent state.\n'
+      msg += 'No actions will be performed in this step.'
+      self.sendStatus({'header': msg})
+      d.addCallback(self._sendRC)
+      return d
+
     # Do we need to clobber anything?
     if self.mode in ("copy", "clobber", "export"):
       d.addCallback(self.doClobber, self.workdir)
     if not (self.sourcedirIsUpdateable() and self.sourcedataMatches()):
       # the directory cannot be updated, so we have to clobber it.
       # Perhaps the master just changed modes from 'export' to
       # 'update'.
       d.addCallback(self.doClobber, self.srcdir)
     elif self.sourcedirIsPatched():
       # The directory is patched. Revert the sources.
@@ skipping 321 matching lines @@
   try:
     # We run this code in a try because it fails with an assertion if
     # the module is loaded twice.
     commandRegistry['gclient'] = 'slave.chromium_commands.GClient'
     return
   except (AssertionError, NameError):
     pass
 
 
 RegisterCommands()