Gerrit git cl upload: warn and offer to remove Gerrit commit-msg hook.

git_cl.py

 #!/usr/bin/env python
 # 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.
 
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
 """A git-command for integrating reviews on Rietveld and Gerrit."""
 
 from distutils.version import LooseVersion
@@ skipping 2296 matching lines @@
     else:
       part = parsed_url.path
     match = re.match('(/c)?/(\d+)(/(\d+)?/?)?$', part)
     if match:
       return _ParsedIssueNumberArgument(
           issue=int(match.group(2)),
           patchset=int(match.group(4)) if match.group(4) else None,
           hostname=parsed_url.netloc)
     return None
 
+  def _GerritCommitMsgHookCheck(self, offer_removal):
+    hook = os.path.join(settings.GetRoot(), '.git', 'hooks', 'commit-msg')
+    if not os.path.exists(hook):
+      return
+    # Crude attempt to distinguish Gerrit Codereview hook from potentially
+    # custom developer made one.
+    data = gclient_utils.FileRead(hook)
+    if not('From Gerrit Code Review' in data and 'add_ChangeId()' in data):
+      return
+    print('Warning: you have Gerrit commit-msg hook installed.\n'
+          'It is not neccessary for uploading with git cl in squash mode, '
+          'and may interfere with it in subtle ways.\n'
+          'We recommend you remove the commit-msg hook.')
+    if offer_removal:
+      reply = ask_for_data('Do you want to remove it now? [Yes/No]')
+      if reply.lower().startswith('y'):
+        gclient_utils.rm_file_or_tree(hook)
+        print('Gerrit commit-msg hook removed.')
+      else:
+        print('OK, will keep Gerrit commit-msg hook in place.')
+
   def CMDUploadChange(self, options, args, change):
     """Upload the current branch to Gerrit."""
     if options.squash and options.no_squash:
       DieWithError('Can only use one of --squash or --no-squash')
     options.squash = ((settings.GetSquashGerritUploads() or options.squash) and
                       not options.no_squash)
     # We assume the remote called "origin" is the one we want.
     # It is probably not worthwhile to support different workflows.
     gerrit_remote = 'origin'
 
     remote, remote_branch = self.GetRemoteBranch()
     branch = GetTargetRef(remote, remote_branch, options.target_branch,
                           pending_prefix='')
 
     if options.squash:
+      self._GerritCommitMsgHookCheck(offer_removal=not options.force)
       if not self.GetIssue():
         # TODO(tandrii): deperecate this after 2016Q2.  Backwards compatibility
         # with shadow branch, which used to contain change-id for a given
         # branch, using which we can fetch actual issue number and set it as the
         # property of the branch, which is the new way.
         message = RunGitSilent([
             'show', '--format=%B', '-s',
             'refs/heads/git_cl_uploads/%s' % self.GetBranch()])
         if message:
           change_ids = git_footers.get_footer_change_id(message.strip())
@@ skipping 2593 matching lines @@
 if __name__ == '__main__':
   # These affect sys.stdout so do it outside of main() to simplify mocks in
   # unit testing.
   fix_encoding.fix_encoding()
   setup_color.init()
   try:
     sys.exit(main(sys.argv[1:]))
   except KeyboardInterrupt:
     sys.stderr.write('interrupted\n')
     sys.exit(1)