Python 3.12 and generics

[dantownsend]

We use slotscheck in the CI for Piccolo and sister projects.

For Python 3.12, they changed Generic - it no longer defines __slots__.

This means code like this now fails slotscheck:

https://github.com/piccolo-orm/piccolo/blob/febe5bbdc76cbcba50a994187cf9d953d52a00d3/piccolo/engine/base.py#L27

I know there's a new syntax for defining generics in Python 3.12, but as Piccolo supports Python 3.8 and above, it's harder to implement.

Any ideas how we can fix this? Maybe a special case for Generic in slotscheck (I haven't checked whether using Generic does invalidate the slots in child classes, but I assume not).

Thanks!

[ariebovenberg]

Hi @dantownsend, thanks for opening this issue. I'm having a look at this today

[ariebovenberg]

Looks like Generic was moved to an extension module, and didn't define __slots__ anymore. A special case needed to be added, because it does (thankfully) still behave like a properly slotted class.

[dantownsend]

@ariebovenberg Yeah, that's my understanding too. Thanks a lot for looking into it so quickly 👍

[ariebovenberg]

version 0.17.1 is now out on PyPI with the fix 🔧

[dantownsend]

@ariebovenberg Awesome, thanks a lot! 🎉🎉🎉