Make roll_dep.py work on Windows

roll_dep.py

 #!/usr/bin/env python
 # Copyright 2015 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.
 
 """Rolls DEPS controlled dependency.
 
 Works only with git checkout and git dependencies.
 """
 
 import optparse
 import os
 import re
 import subprocess
 import sys
 
 
+NEED_SHELL = sys.platform.startswith('win')
+
+
+def check_output(*args, **kwargs):
+  """subprocess.check_output() passing shell=True on Windows for git."""
+  kwargs.setdefault('shell', NEED_SHELL)
+  return subprocess.check_output(*args, **kwargs)
+
+
+def check_call(*args, **kwargs):
+  """subprocess.check_call() passing shell=True on Windows for git."""
+  kwargs.setdefault('shell', NEED_SHELL)
+  subprocess.check_call(*args, **kwargs)
+
+
 def is_pristine(root, merge_base='origin/master'):
   """Returns True if a git checkout is pristine."""
   cmd = ['git', 'diff', '--ignore-submodules', merge_base]
-  return not (
-      subprocess.check_output(cmd, cwd=root).strip() or
-      subprocess.check_output(cmd + ['--cached'], cwd=root).strip())
+  return not (check_output(cmd, cwd=root).strip() or
+              check_output(cmd + ['--cached'], cwd=root).strip())
 
 
 def roll(root, deps_dir, key, reviewers, bug):
   deps = os.path.join(root, 'DEPS')
   try:
     with open(deps, 'rb') as f:
       deps_content = f.read()
   except OSError:
     print >> sys.stderr, (
         'Ensure the script is run in the directory containing DEPS file.')
     return 1
 
   if not is_pristine(root):
     print >> sys.stderr, 'Ensure %s is clean first.' % root
     return 1
 
-  full_dir = os.path.join(os.path.dirname(root), deps_dir)
-  head = subprocess.check_output(
+  full_dir = os.path.normpath(os.path.join(os.path.dirname(root), deps_dir))
+  head = check_output(
       ['git', 'rev-parse', 'HEAD'], cwd=full_dir).strip()
 
   if not head in deps_content:
     print('Warning: %s is not checked out at the expected revision in DEPS' %
           deps_dir)
     # It happens if the user checked out a branch in the dependency by himself.
     # Fall back to reading the DEPS to figure out the original commit.
     for i in deps_content.splitlines():
       m = re.match(r'\s+"' + key + '": "([a-z0-9]{40})",', i)
       if m:
         head = m.group(1)
         break
     else:
       print >> sys.stderr, 'Expected to find commit %s for %s in DEPS' % (
           head, key)
       return 1
 
   print('Found old revision %s' % head)
 
-  subprocess.check_call(['git', 'fetch', 'origin'], cwd=full_dir)
-  master = subprocess.check_output(
+  check_call(['git', 'fetch', 'origin'], cwd=full_dir)
+  master = check_output(
       ['git', 'rev-parse', 'origin/master'], cwd=full_dir).strip()
   print('Found new revision %s' % master)
 
   if master == head:
     print('No revision to roll!')
     return 1
 
   commit_range = '%s..%s' % (head[:9], master[:9])
 
-  logs = subprocess.check_output(
+  logs = check_output(
       ['git', 'log', commit_range, '--date=short', '--format=%ad %ae %s'],
       cwd=full_dir).strip()
   logs = re.sub(r'(?m)^(\d\d\d\d-\d\d-\d\d [^@]+)@[^ ]+( .*)$', r'\1\2', logs)
   cmd = 'git log %s --date=short --format=\'%%ad %%ae %%s\'' % commit_range
   reviewer = 'R=%s\n' % ','.join(reviewers) if reviewers else ''
   bug = 'BUG=%s\n' % bug if bug else ''
   msg = (
       'Roll %s/ to %s.\n'
       '\n'
       '$ %s\n'
       '%s\n\n'
       '%s'
       '%s') % (
           deps_dir,
           master,
           cmd,
           logs,
           reviewer,
           bug)
 
   print('Commit message:')
   print('\n'.join('    ' + i for i in msg.splitlines()))
   deps_content = deps_content.replace(head, master)
   with open(deps, 'wb') as f:
     f.write(deps_content)
-  subprocess.check_call(['git', 'add', 'DEPS'], cwd=root)
-  subprocess.check_call(['git', 'commit', '-m', msg], cwd=root)
+  check_call(['git', 'add', 'DEPS'], cwd=root)
+  check_call(['git', 'commit', '-m', msg], cwd=root)
   print('')
   if not reviewers:
     print('You forgot to pass -r, make sure to insert a R=foo@example.com line')
     print('to the commit description before emailing.')
     print('')
   print('Run:')
   print('  git cl upload --send-mail')
   return 0
 
 
 def main():
   parser = optparse.OptionParser(
       description=sys.modules[__name__].__doc__,
       usage='roll-dep [flags] <dependency path> <variable>')
   parser.add_option(
       '-r', '--reviewer', default='',
       help='To specify multiple reviewers, use comma separated list, e.g. '
-           '-r joe,jack,john. Defaults to @chromium.org')
+           '-r joe,jane,john. Defaults to @chromium.org')
   parser.add_option('-b', '--bug', default='')
   options, args = parser.parse_args()
   if not len(args) or len(args) > 2:
     parser.error('Expect one or two arguments' % args)
 
   reviewers = None
   if options.reviewer:
     reviewers = options.reviewer.split(',')
     for i, r in enumerate(reviewers):
       if not '@' in r:
         reviewers[i] = r + '@chromium.org'
 
   return roll(
       os.getcwd(),
       args[0],
       args[1] if len(args) > 1 else None,
       reviewers,
       options.bug)
 
 
 if __name__ == '__main__':
   sys.exit(main())