Python version: factor mapping causes side-effect on Tox v4

[bittner]

Describe the bug
tox-gh-actions uses a colon : in the version = factor mapping, which causes Tox to interpret the left part (version) as "additional environments". See tox-dev/tox#3014 for details.

To Reproduce

1. Configure a [gh-actions] section with default mappings in tox.ini
2. Run tox list locally
3. Inspect the output (versions are listed as "additional environments")

Expected behavior
The tox-gh-actions configuration should not confuse Tox. It should not be possible that keys of the python mapping are interpreted as environments. This may be achieved by replacing : by =.

Additional context
A Tox maintainer suggests to use tox-gh instead of tox-gh-actions in tox-dev/tox#3014. Unfortunately, that plugin only supports Python > 3.6 -- and I have projects that try to support older versions of Python.

I'd be interested in tox-gh-actions fixing the issue and keep supporting older Pythons.

[ymyzk]

Thanks for reporting the issue.

The use of : is imported from tox-dev/tox-travis (it's a plugin under tox-dev 😅) https://tox-travis.readthedocs.io/en/stable/envlist.html when tox-gh-action is created initially. As changing the syntax will cause build failures, we need to think about how to fix this issue carefully.

By updating our parser, we may be able to both : and = and migrate to = eventually in the future. I'll find time to think about this problem.

[bittner]

By updating our parser, we may be able to both : and = and migrate to = eventually in the future.

That sounds promising. Lets proceed with that. 🚀