Start documenting abi3 support

[alex]

No description provided.

[davidhewitt]

This PR documents the abi3 feature, but I understood we decided to invert the pattern and instead have an unstable-abi feature which would be enabled by default?

There was a commit on the abi3 branch to this effect: 1941f4d

However that change doesn't appear to be present in the latest version of #1152 - perhaps came unstuck with a merge conflict?

[kngwyu]

I understood we decided to invert the pattern and instead have an unstable-abi feature which would be enabled by default?

I inverted the change to introduce py3*-abi3 features.

[davidhewitt]

I inverted the change to introduce py3*-abi3 features.

Can you elaborate? I don't think I can see these py3*-abi3 features on that branch at the moment either.

[kngwyu]

Sorry, I meant that 'I changed it to abi3 so that it would be integrated well with py3*-abi3 features that we're going to introduce based on the discussion in #1195'

[alex]

Yes, this documents the branch as it exists today, and I followed this documentation when I wrote the tests for setuptools-rust, so I'm sure it works :-)

[davidhewitt]

👍 in that case I propose let's merge it and review everything on the abi3 branch!