Fix issue with stale cache from bad builds.

bin/cbuildbot.py

 #!/usr/bin/python
 
 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """CBuildbot is wrapper around the build process used by the pre-flight queue"""
 
 import errno
 import re
@@ skipping 327 matching lines @@
   _UprevAllPackages(buildroot)
 
 
 def _UprevCleanup(buildroot, error_ok=False):
   """Clean up after a previous uprev attempt."""
   cwd = os.path.join(buildroot, 'src', 'scripts')
   RunCommand(['./cros_mark_as_stable', '--srcroot=..',
               '--tracking_branch="cros/master"', 'clean'],
              cwd=cwd, error_ok=error_ok)
 
+  workon_packages = RunCommand(['./cros_workon', 'list'],
+                               enter_chroot=True, cwd=cwd, error_ok=error_ok,
+                               redirect_stdout=True)
+  if workon_packages:
+    Info('Cleaning up workon packages %s' % workon_packages)
+    RunCommand(['./cros_workon', 'stop'] + workon_packages.split(),
+               enter_chroot=True, cwd=cwd, error_ok=False)
+
 
 def _UprevPush(buildroot):
   """Pushes uprev changes to the main line."""
   cwd = os.path.join(buildroot, 'src', 'scripts')
   RunCommand(['./cros_mark_as_stable', '--srcroot=..',
               '--tracking_branch="cros/master"',
               '--push_options', '--bypass-hooks -f', 'push'],
              cwd=cwd)
 
 
@@ skipping 74 matching lines @@
 
     if buildconfig['smoke_bvt']:
       _BuildVMImageForTesting(buildroot)
       _RunSmokeSuite(buildroot)
 
     if buildconfig['uprev']:
       if buildconfig['master']:
         # Master bot needs to check if the other slaves completed.
         if cbuildbot_comm.HaveSlavesCompleted(config):
           _UprevPush(buildroot)
-          _UprevCleanup(buildroot)
         else:
           # At least one of the slaves failed or we timed out.
           _UprevCleanup(buildroot)
           Die('CBUILDBOT - One of the slaves has failed!!!')
       else:
         # Publish my status to the master if its expecting it.
         if buildconfig['important']:
           cbuildbot_comm.PublishStatus(cbuildbot_comm.STATUS_BUILD_COMPLETE)
 
-        _UprevCleanup(buildroot)
+      _UprevCleanup(buildroot)
   except:
     # Send failure to master bot.
     if not buildconfig['master'] and buildconfig['important']:
       cbuildbot_comm.PublishStatus(cbuildbot_comm.STATUS_BUILD_FAILED)
 
     raise
 
 
 if __name__ == '__main__':
     main()