Add compatibility for Pyodide-tagged wheels

[hoodmane]

We are changing our wheel platform tag to pyemscripten_2024_0 so we need to teach packaging to map Emscripten platform to this.

cc @henryiii

[hoodmane]

@mayeut @henryiii @pradyunsg would appreciate review on this from any of you (and running the workflow).

[hoodmane]

Tests and coverage check now pass locally for me.

[agriyakhetarpal]

I stumbled into this PR, somehow – I guess the tests are valid for only Python 3.12 and should be skipped for other Python versions, @hoodmane?

[agriyakhetarpal]

Now, we also pre-emptively need 2025_0 as we broke/will be breaking the ABI.

[juntyr]

+1 - it would be great if packaging installed from PyPi would just work out of the box in Pyodide

[agriyakhetarpal]

I guess the only remaining parts here are to generalise the ABI tags, so that emscripten_x_y_zw and pyodide_abcd_e, where $$x, y, z, w, a, b, c, d, e ∈ [0, 9] $$ work, and skip the tests on unsupported Python versions (by probably grabbing the Python version from pyodide config get python_version)?

[ofek]

What are the next steps for this?

[hoodmane]

This can only be merged once PEP 783 is approved.

[ofek]

Indeed, and what's the status of that? I haven't seen any discussion update in months so I don't quite understand the state of the proposal.

[hoodmane]

Well I assume you also asked on the discuss thread? You can see the new comments there.
https://discuss.python.org/t/pep-783-emscripten-packaging/86862/64

[ofek]

Ah I don't have notifications for that enabled apparently, thanks a lot!