fix: convert to cstrings in PyString::from_object

[Dr-Emann]

fixes #5005

This only fixes the API, and adds a test of the API, it does not deprecate the API or introduce a version which takes &CStr directly, this can be done later.

[davidhewitt]

Thanks!

[Wumpf]

@davidhewitt thank you so much for releasing this so timely in a patch release! Do you plan on backporting this to the 0.23.x line as well? I'd like to update to 0.24.x but we also depend on arrow-rs which only recently moved their main branch to 0.24, so stuck on 0.23.x for the moment.

[mejrs]

@davidhewitt thank you so much for releasing this so timely in a patch release! Do you plan on backporting this to the 0.23.x line as well? I'd like to update to 0.24.x but we also depend on arrow-rs which only recently moved their main branch to 0.24, so stuck on 0.23.x for the moment.

I don't see why not, but note that you can safely use this api if you take care to null terminate the string yourself, like "utf-8\0".

[davidhewitt]

As per #5005 (comment), I was not planning to backport. I suspect that almost nobody was using this API, hence why it was broken for so long, so I think the ecosystem risk is low.