Fix cleanup so we don't have to clobber as much when failures occur

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 198 matching lines @@
   RunCommand(['sudo', 'rm', '-rf', buildroot])
   MakeDir(buildroot, parents=True)
   RunCommand(['repo', 'init', '-u', 'http://src.chromium.org/git/manifest'],
              cwd=buildroot, input='\n\ny\n')
   RepoSync(buildroot, rw_checkout, retries)
 
 
 def _IncrementalCheckout(buildroot, rw_checkout=True,
                          retries=_DEFAULT_RETRIES):
   """Performs a checkout without clobbering previous checkout."""
+  _UprevCleanup(buildroot, error_ok=True)
   RepoSync(buildroot, rw_checkout, retries)
 
 
 def _MakeChroot(buildroot):
   """Wrapper around make_chroot."""
   cwd = os.path.join(buildroot, 'src', 'scripts')
   RunCommand(['./make_chroot', '--fast'], cwd=cwd)
 
 
 def _SetupBoard(buildroot, board='x86-generic'):
@@ skipping 45 matching lines @@
   #if revisions != 'None':
   #  print >> sys.stderr, 'CBUILDBOT Revision list found %s' % revisions
   #  revision_list = _ParseRevisionString(revisions,
   #      _CreateRepoDictionary(buildroot, board))
   #  _UprevFromRevisionList(buildroot, revision_list)
   #else:
   Info('CBUILDBOT Revving all')
   _UprevAllPackages(buildroot)
 
 
-def _UprevCleanup(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)
+             cwd=cwd, error_ok=error_ok)
 
 
 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 90 matching lines @@
   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()