Presubmit recipe: rebase Gerrit patches.

scripts/slave/recipes/run_presubmit.py

 # Copyright (c) 2013 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.
 
 DEPS = [
   'depot_tools/bot_update',
   'depot_tools/gclient',
   'depot_tools/git',
   'depot_tools/presubmit',
   'recipe_engine/json',
   'recipe_engine/path',
   'recipe_engine/properties',
   'recipe_engine/python',
   'recipe_engine/step',
   'depot_tools/tryserver',
   'depot_tools/rietveld',
   'v8',
   'webrtc',
 ]
 
 
 def _RunStepsInternal(api):
   repo_name = api.properties['repo_name']
   codereview_auth = api.properties.get('codereview_auth', False)
   force_checkout = api.properties.get('force_checkout', False)
+  patch_storage = api.properties.get('patch_storage', 'rietveld')
 
   api.gclient.set_config(repo_name)
 
+  kwargs = {}
+  if patch_storage == 'gerrit':
+    kwargs['gerrit_rebase_patch_ref'] = True
   bot_update_step = api.bot_update.ensure_checkout(
       force=force_checkout,
-      patch_oauth2=codereview_auth)
+      patch_oauth2=codereview_auth,
+      **kwargs)
   relative_root = api.gclient.calculate_patch_root(
       api.properties['patch_project']).rstrip('/')
   got_revision_property = api.gclient.c.got_revision_mapping[relative_root]
   upstream = bot_update_step.json.output['properties'].get(
       got_revision_property)
   if (not upstream or
       isinstance(upstream, int) or
       (upstream.isdigit() and len(upstream) < 40)):
     # If got_revision is an svn revision, then use got_revision_git.
     upstream = bot_update_step.json.output['properties'].get(
         '%s_git' % got_revision_property) or ''
 
   abs_root = api.path['slave_build'].join(relative_root)
   # TODO(hinoka): Extract email/name from issue?
   api.git('-c', 'user.email=commit-bot@chromium.org',
           '-c', 'user.name=The Commit Bot',
           'commit', '-a', '-m', 'Committed patch',
           name='commit git patch', cwd=abs_root)
 
   if api.properties.get('runhooks'):
     api.gclient.runhooks()
 
-  patch_storage = api.properties.get('patch_storage', 'rietveld')
   if patch_storage == 'rietveld':
     presubmit_args = [
       '--issue', api.properties['issue'],
       '--patchset', api.properties['patchset'],
       '--rietveld_url', api.properties['rietveld'],
       '--rietveld_fetch',
     ]
     if codereview_auth:
       presubmit_args.extend([
           '--rietveld_email_file',
@@ skipping 165 matching lines @@
 
   yield (
     api.test('presubmit-infra-failure') +
     api.properties.tryserver(
         mastername='tryserver.chromium.linux',
         buildername='chromium_presubmit',
         repo_name='chromium',
         patch_project='chromium') +
     api.step_data('presubmit', api.json.output({}, retcode=2))
   )