git cl issue: add --json switch for machine-readable output

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 __future__ import print_function
@@ skipping 3428 matching lines @@
       if color in line.upper():
         # Extract whitespaces first and the leading '-'.
         indent = len(line) - len(line.lstrip(' ')) + 1
         return line[:indent] + getattr(Fore, color) + line[indent:] + Fore.RESET
     return line
 
   lines = CMDstatus.__doc__.splitlines()
   CMDstatus.__doc__ = '\n'.join(colorize_line(l) for l in lines)
 
 
+def write_json(path, contents):
+  with open(path, 'w') as f:
+    json.dump(contents, f)
+
+
 @subcommand.usage('[issue_number]')
 def CMDissue(parser, args):
   """Sets or displays the current code review issue number.
 
   Pass issue number 0 to clear the current issue.
   """
   parser.add_option('-r', '--reverse', action='store_true',
                     help='Lookup the branch(es) for the specified issues. If '
                          'no issues are specified, all branches with mapped '
                          'issues will be listed.')
+  parser.add_option('--json', help='Path to JSON output file.')
   _add_codereview_select_options(parser)
   options, args = parser.parse_args(args)
   _process_codereview_select_options(parser, options)
 
   if options.reverse:
     branches = RunGit(['for-each-ref', 'refs/heads',
                        '--format=%(refname:short)']).splitlines()
 
     # Reverse issue lookup.
     issue_branch_map = {}
     for branch in branches:
       cl = Changelist(branchref=branch)
       issue_branch_map.setdefault(cl.GetIssue(), []).append(branch)
     if not args:
       args = sorted(issue_branch_map.iterkeys())
+    result = {}
     for issue in args:
       if not issue:
         continue
+      result[int(issue)] = issue_branch_map.get(int(issue))
       print('Branch for issue number %s: %s' % (
           issue, ', '.join(issue_branch_map.get(int(issue)) or ('None',))))
+    if options.json:
+      write_json(options.json, result)
   else:
     cl = Changelist(codereview=options.forced_codereview)
     if len(args) > 0:
       try:
         issue = int(args[0])
       except ValueError:
         DieWithError('Pass a number to set the issue or none to list it.\n'
                      'Maybe you want to run git cl status?')
       cl.SetIssue(issue)
     print('Issue number: %s (%s)' % (cl.GetIssue(), cl.GetIssueURL()))
+    if options.json:
+      write_json(options.json, {
+        'issue': cl.GetIssue(),
+        'issue_url': cl.GetIssueURL(),
+      })
   return 0
 
 
 def CMDcomments(parser, args):
   """Shows or posts review comments for any changelist."""
   parser.add_option('-a', '--add-comment', dest='comment',
                     help='comment to add to an issue')
   parser.add_option('-i', dest='issue',
                     help="review issue id (defaults to current issue)")
   parser.add_option('-j', '--json-file',
@@ skipping 1688 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)