Fix crash in roll_dep.py when key == None

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')
 
-NEED_SHELL = sys.platform.startswith('win')
+
+class Error(Exception):
+  pass
 
 
 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 (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 (IOError, OSError):
-    print >> sys.stderr, (
-        'Ensure the script is run in the directory containing DEPS file.')
-    return 1
+    raise Error('Ensure the script is run in the directory '
+                'containing DEPS file.')
 
   if not is_pristine(root):
-    print >> sys.stderr, 'Ensure %s is clean first.' % root
-    return 1
+    raise Error('Ensure %s is clean first.' % root)
 
   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()
+  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)
+    if key is None:
+      print("Warning: no key specified.  Using '%s'." % deps_dir)
+      key = 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
+      raise Error('Expected to find commit %s for %s in DEPS' % (head, key))
 
   print('Found old revision %s' % head)
 
   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
+    raise Error('No revision to roll!')
 
   commit_range = '%s..%s' % (head[:9], master[:9])
 
   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 ''
@@ skipping 18 matching lines @@
     f.write(deps_content)
   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,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)
+  try:
+    roll(
+        os.getcwd(),
+        deps_dir=args[0],
+        key=args[1] if len(args) > 1 else None,
+        reviewers=reviewers,
+        bug=options.bug)
+
+  except Error as e:
+    sys.stderr.write('error: %s\n' % e)
+    return 1
+
+  return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())