Add safely-roll-webkit.py to streamline webkit rolls.

tools/safely-roll-webkit.py

Index: tools/safely-roll-webkit.py
diff --git a/tools/safely-roll-webkit.py b/tools/safely-roll-webkit.py
new file mode 100755
index 0000000000000000000000000000000000000000..97260fb671c4631e0d6186ae3a981ee5268ef2d8
--- /dev/null
+++ b/tools/safely-roll-webkit.py
@@ -0,0 +1,82 @@
+#!/usr/bin/env python
+# Copyright (c) 2011 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.
+
+"""Generate a CL to roll webkit to the specified revision number and post
+it to Rietveld so that the CL will land automatically if it passes the
+commit-queue's checks.
+"""
+
+import logging
+import optparse
+import os
+import re
+import sys
+
+import find_depot_tools
+import scm
+import subprocess2
+
+
+def die_with_error(msg):
+  print >> sys.stderr, msg
+  sys.exit(1)
+
+
+def process_deps(path, new_rev):
+  """Update webkit_revision to |new_issue|.
+
+  A bit hacky, could it be made better?
+  """
+  content = open(path).read()
+  old_line = r'(\s+)"webkit_revision": "(\d+)",'
+  new_line = r'\1"webkit_revision": "%d",' % new_rev
+  new_content = re.sub(old_line, new_line, content, 1)
+  if new_content == content:
+    die_with_error('Failed to update the DEPS file')
+  open(path, 'w').write(new_content)
+
+
+def main():
+  tool_dir = os.path.dirname(os.path.abspath(__file__))
+  parser = optparse.OptionParser(usage='<new webkit rev>')
+  parser.add_option('-v', '--verbose', action='count', default=0)
+  options, args = parser.parse_args()
+  logging.basicConfig(
+      level=
+          [logging.WARNING, logging.INFO, logging.DEBUG][
+            min(2, options.verbose)])
+  if len(args) != 1:
+    parser.error('Need only one arg: new webkit revision to roll to.')
+
+  root_dir = os.path.dirname(tool_dir)
+  os.chdir(root_dir)
+
+  new_rev = int(args[0])
+  msg = 'Roll webkit revision to %s' % new_rev
+  print msg
+
+  # Silence the editor.
+  os.environ['EDITOR'] = '/bin/true'
+
+  old_branch = scm.GIT.GetBranch(root_dir)
+  if old_branch == 'webkit_roll':
+    parser.error(
+        'Please delete the branch webkit_roll and move to a different branch')
+  subprocess2.check_output(
+      ['git', 'checkout', '-b', 'webkit_roll', 'origin/trunk'])
+  try:
+    process_deps(os.path.join(root_dir, 'DEPS'), new_rev)
+    commit_msg = msg + '\nTBR=\n'
+    subprocess2.check_output(['git', 'commit', '-m', commit_msg, 'DEPS'])
+    subprocess2.check_call(['git', 'diff', 'origin/trunk'])
+    subprocess2.check_call(['git', 'cl', 'upload', '--use-commit-queue'])
+  finally:
+    subprocess2.check_output(['git', 'checkout', old_branch])
+    subprocess2.check_output(['git', 'branch', '-D', 'webkit_roll'])
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main())