Test Python 3.8

[MaxGhenis]

Python 3.10 will also be launched in about 6 weeks.

[MattiSG]

Thanks @MaxGhenis!

Once #1030 is approved, we should have enough test runners to apply a matrix strategy that should let us test on several Python versions at once :smiley:

In order to help prioritise and avoid resource wastage, could you please share any deployment constraints you have / know of? With which version of Python do you currently use OpenFisca? 🙂

[bonjourmauko]

I've been tinkering with a working prototype here #1031 😃 (it works in local if you want to try it out).

[MaxGhenis]

In order to help prioritise and avoid resource wastage, could you please share any deployment constraints you have / know of?

No constraints, though there could be general performance improvements. @nikhilwoodruff also mentioned code structuring improvements in 3.9.

With which version of Python do you currently use OpenFisca?

3.7

[MattiSG]

#1030 has been approved, a preliminary implementation in https://github.com/openfisca/openfisca-france/pull/1663 seems to show that 3.7 and 3.8 pass tests, while 3.9 fails at least for the Web API.

[bonjourmauko]

@MattiSG great! In #1031 I've got all the tests passing for 3.9 but test_shell_script_with_reform, we can take a look together @HAEKADI if you think it could help.

[HAEKADI]

@maukoquiroga The api-test keeps running without exiting for Python 3.9. You can take a look at the logs on GitHub Actions. I had to stop the workflow manually 🤔

[MaxGhenis]

Since Python 3.9 has issues (https://github.com/openfisca/openfisca-core/issues/1035#issuecomment-913693451), I shrunk this issue down to Python 3.8. Python 3.8 support would be especially useful since it's the default conda Python version, and that's how many developers install Python.