path to full python2+python3 support

[mr-c]

Building off of #306, #287, and #305

• populate the typeshed/3 directory with any needed type stubs
  • submit these type stubs to https://github.com/python/typeshed
• add code to use avro-python3 as needed here and in schema_salad
• pass mypy without --py2 (test with make mypy3 after pip install -rrequirements.txt in a py3 venv)
• pass tests running using python3
• pass CWL conformance tests using python3

[manu-chroma]

Regarding use of avro-python3 and it's compatibility with python 2:

• https://issues.apache.org/jira/browse/AVRO-1788
• AVRO-1788: Implement Python 2 API apache/avro#133

[mr-c]

We should consider signing the http://www.python3statement.org/

[manu-chroma]

@mr-c can you highlight some of the reasons why the codebase is currently incompatible with windows?

I'm tried setting up schema_salad in windows environment and tried running some tests which were mostly failing.

[mr-c]

@manu-chroma I don't have access to MS Windows myself so the incompatibility is due to not being targeted nor tested.

[AleksandrSl]

@mr-c Is there a way I can help with this issue?

[mr-c]

Hello @AleksandrSl, thank you for your offer.

All contributions are welcome -- though we do have pending Google Summer of Code applications on this topic.

[tetron]

See common-workflow-language/schema_salad#109 (comment)

[manu-chroma]

It seems apt to close this issue now, since we've released a Python 3 compatible version on pypi and integrated Python 3 in all our tests. I have opened an issue regarding avro package for reference in the future: #524

Thank you, everyone, for your efforts. :)