port Python::import to Bound API

[Icxolu]

Part of #3684

This ports the Python::import over to the Bound API. This does not port PyModule::import, which can be done separately and is currently part of #3775. I left a FIXME there, indicating that it needs to change in the future, but it should also popup once PyModule::import gets deprecated.

[codspeed-hq]

CodSpeed Performance Report

Merging #3832 will degrade performances by 28.99%

_{Comparing Icxolu:python-import (dc36403) with main (e308c8d)}

Summary

⚡ 3 improvements
❌ 3 regressions
✅ 73 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	Icxolu:python-import	Change
❌	mapping_from_dict	272.2 ns	355.6 ns	-23.44%
⚡	list_via_downcast	185 ns	157.2 ns	+17.67%
⚡	list_via_extract	392.2 ns	336.7 ns	+16.5%
⚡	not_a_list_via_downcast	244.4 ns	216.7 ns	+12.82%
❌	sequence_from_list	272.2 ns	383.3 ns	-28.99%
❌	sequence_from_tuple	232.8 ns	260.6 ns	-10.66%

[davidhewitt]

Thanks yet again! Looks great, it's nice to see a whole bunch of .as_borrowed() and .as_gil_ref() calls getting removed.

Only one tiny adjustment which I thought could be worth doing, plus a couple of thoughts which aren't really for this PR and more follow-ups...

[davidhewitt]

Nice tidy ups 👍

[davidhewitt]

👍 nicely done figuring out the to_str / to_cow tweaks on PyString. I guess we should probably add a note about PyString::to_str to the migration guide; I don't think we have one at the moment...

[Icxolu]

Yeah, thats a good idea. I think I stumbled over this twice already...

[davidhewitt]

Suggested change

	use pyo3::{prelude::PyAnyMethods, types::PyDate, Python};
	use pyo3::{prelude::*, types::PyDate};

Slightly related thought: I've been thinking we might want to make these traits public at some path other than the prelude, just for the few occasions when users might want to directly name them (?).

One option would be to make their existing paths public, e.g. pyo3::types::any::PyAnyMethods. We'd just need to be careful we didn't accidentally make other APIs public at the same time.

[Icxolu]

We could also reexport them from pyo3::types, like we already do for the types themselfs

[davidhewitt]

pyo3::types I think makes a lot of sense. That module is already public, and we can control easily what gets exposed 👍

[davidhewitt]

I decided to commit the tiny fixup & merge now, and we can continue to discuss the follow-ups while potentially I rebase and get #3775 ready for review.