WIP: better way to get python package metadata

[rotu]

Instead of monkey-patching setup.py to harvest the args, use distutils.core.run_setup which returns the actual metadata, inclusive of cfg files.

[dirk-thomas]

Interesting, I didn't know about distutils.core.run_setup.

I tried using the function on some of the existing packages but it seems it has trouble even parsing some of the existing setup.cfg files: e.g. https://github.com/ros2/ros2cli/blob/9f2854465ee704ee9b6c58c91c286fef5939f411/ros2multicast/setup.cfg

If this approach works it might be better to replace the Python identification in colcon_core and get rid of this package altogether.

[rotu]

That package seems to work just fine for me. There are some gotchas:

1. Some of the properties of the distribution object seem like they should work but don't (e.g. you need to use .get_name() or .metadata.name or dist.command_options['metadata']['name'][1] -- .name will seemingly always be 0).
2. It only properly finds setuptools.cfg if it's in the cwd.

>>> os.chdir('/Users/dan/Downloads/ros2cli-9f2854465ee704ee9b6c58c91c286fef5939f411/ros2multicast')
>>> dist=run_setup('setup.py')
>>> dist.dump_option_dicts()
option dict for 'build_ext' command:
  {'include_dirs': ('/usr/local/Cellar/python/3.7.4/Frameworks/Python.framework/Versions/3.7/lib/python3.7/distutils/distutils.cfg',
                    '/usr/local/include:/usr/local/opt/openssl/include:/usr/local/opt/sqlite/include'),
   'library_dirs': ('/usr/local/Cellar/python/3.7.4/Frameworks/Python.framework/Versions/3.7/lib/python3.7/distutils/distutils.cfg',
                    '/usr/local/lib:/usr/local/opt/openssl/lib:/usr/local/opt/sqlite/lib')}
option dict for 'install' command:
  {'prefix': ('/usr/local/Cellar/python/3.7.4/Frameworks/Python.framework/Versions/3.7/lib/python3.7/distutils/distutils.cfg',
              '/usr/local')}
option dict for 'metadata' command:
  {'author': ('setup.cfg', 'Dirk Thomas'),
   'author_email': ('setup.cfg', 'dthomas@osrfoundation.org'),
   'classifiers': ('setup.cfg',
                   '\n'
                   'Environment :: Console\n'
                   'Intended Audience :: Developers\n'
                   'License :: OSI Approved :: Apache Software License\n'
                   'Programming Language :: Python'),
   'description': ('setup.cfg',
                   'The multicast command for ROS 2 command line tools.'),
   'keywords': ('setup.cfg', 'ros2cli'),
   'license': ('setup.cfg', 'Apache License, Version 2.0'),
   'long_description': ('setup.cfg', 'file: README.rst'),
   'maintainer': ('setup.cfg', 'Dirk Thomas'),
   'maintainer_email': ('setup.cfg', 'dthomas@osrfoundation.org'),
   'name': ('setup.cfg', 'ros2multicast'),
   'project_urls': ('setup.cfg',
                    '\n'
                    'GitHub = '
                    'https://github.com/ros2/ros2cli/tree/master/ros2multicast'),
   'version': ('setup.cfg', "'0.6.3'")}
option dict for 'options' command:
  {'install_requires': ('setup.cfg', '\nros2cli'),
   'packages': ('setup.cfg', 'find:'),
   'tests_require': ('setup.cfg', '\npytest\npytest-cov'),
   'zip_safe': ('setup.cfg', 'true')}
option dict for 'options.entry_points' command:
  {'ros2cli.command': ('setup.cfg',
                       '\n'
                       'multicast = '
                       'ros2multicast.command.multicast:MulticastCommand'),
   'ros2cli.extension_point': ('setup.cfg',
                               '\n'
                               'ros2multicast.verb = '
                               'ros2multicast.verb:VerbExtension'),
   'ros2multicast.verb': ('setup.cfg',
                          '\n'
                          'receive = ros2multicast.verb.receive:ReceiveVerb\n'
                          'send = ros2multicast.verb.send:SendVerb')}

[dirk-thomas]

I think you may have accidentally typed run_setup('setup.cfg') instead of run_setup('setup.py')

🤐 indeed, sorry for the noise...

If this approach works it might be better to replace the Python identification in colcon_core and get rid of this package altogether.

How about proceeding with this instead? Would you like to create a PR against colcon-core with a similar change or do you want me to do it?

[rotu]

How about proceeding with this instead? Would you like to create a PR against colcon-core with a similar change or do you want me to do it?

I'm working on it right now. Closing this PR in preference.