We should make it hard to add a new option to cbuildbot without setting an 'api' version number for it. Multiple people have added new options without setting API versions, which then broke cbuildbot in backwards incompatible ways.

One approach:

  Make the 'api' option required, and set it for all existing values.


Example of an option that already has an API value:

  group.add_remote_option('--git-cache-dir', type='path',
                          api=constants.REEXEC_API_GIT_CACHE_DIR,
                          help='help text here')