Support for |change| argument to |GetPreferredTrySlaves()|, try 2.

git_cl.py

 #!/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.
 
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
 """A git-command for integrating reviews on Rietveld."""
 
 import logging
@@ skipping 470 matching lines @@
     """Set this branch's issue.  If issue=0, clears the issue."""
     if issue:
       RunGit(['config', self._IssueSetting(), str(issue)])
       if self.rietveld_server:
         RunGit(['config', self._RietveldServer(), self.rietveld_server])
     else:
       RunGit(['config', '--unset', self._IssueSetting()])
       self.SetPatchset(0)
     self.has_issue = False
 
-  def RunHook(self, committing, upstream_branch, may_prompt, verbose, author):
-    """Calls sys.exit() if the hook fails; returns a HookResults otherwise."""
+  def GetChange(self, upstream_branch, author):
     root = RunCommand(['git', 'rev-parse', '--show-cdup']).strip() or '.'
     absroot = os.path.abspath(root)
 
     # We use the sha1 of HEAD as a name of this change.
     name = RunCommand(['git', 'rev-parse', 'HEAD']).strip()
     # Need to pass a relative path for msysgit.
     files = scm.GIT.CaptureStatus([root], upstream_branch)
 
     issue = ConvertToInteger(self.GetIssue())
     patchset = ConvertToInteger(self.GetPatchset())
     if issue:
       description = self.GetDescription()
     else:
       # If the change was never uploaded, use the log messages of all commits
       # up to the branch point, as git cl upload will prefill the description
       # with these log messages.
       description = RunCommand(['git', 'log', '--pretty=format:%s%n%n%b',
                                 '%s...' % (upstream_branch)]).strip()
 
     if not author:
       author = RunGit(['config', 'user.email']).strip() or None
-    change = presubmit_support.GitChange(
+    return presubmit_support.GitChange(
         name,
         description,
         absroot,
         files,
         issue,
         patchset,
         author)
 
+  def RunHook(self, committing, upstream_branch, may_prompt, verbose, author):
+    """Calls sys.exit() if the hook fails; returns a HookResults otherwise."""
+    change = self.GetChange(upstream_branch, author)
+
     # Apply watchlists on upload.
     if not committing:
       watchlist = watchlists.Watchlists(change.RepositoryRoot())
       files = [f.LocalPath() for f in change.AffectedFiles()]
       self.SetWatchers(watchlist.GetWatchersForPaths(files))
 
     try:
       output = presubmit_support.DoPresubmitChecks(change, committing,
           verbose=verbose, output_stream=sys.stdout, input_stream=sys.stdin,
           default_presubmit=None, may_prompt=may_prompt,
@@ skipping 896 matching lines @@
              'and retry or visit go/isgaeup.\n%s') % (e.code, str(e)))
 
   # Not a known command. Default to help.
   GenUsage(parser, 'help')
   return CMDhelp(parser, argv)
 
 
 if __name__ == '__main__':
   fix_encoding.fix_encoding()
   sys.exit(main(sys.argv[1:]))