expose Bound::from_owned_ptr etc

[davidhewitt]

Split from #3606

This makes Bound::from_owned_ptr and variants part of the public API, instead of pub(crate).

This is useful for the occasional use case outside of PyO3 which deals with raw FFI. These APIs also have equivalents with the same names which already exist on Py<T>, so it seems to me that we might as well have these.

[codspeed-hq]

CodSpeed Performance Report

Merging #3779 will improve performances by 20.41%

_{Comparing davidhewitt:bound-from-ptr (86f294f) with main (ecb4ecb)}

🎉 Hooray! pytest-codspeed just leveled up to 2.2.0!

A heads-up, this is a breaking change and it might affect your current performance baseline a bit. But here's the exciting part - it's packed with new, cool features and promises improved result stability 🥳!
Curious about what's new? Visit our releases page to delve into all the awesome details about this new version.

Summary

⚡ 4 improvements
✅ 75 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	davidhewitt:bound-from-ptr	Change
⚡	list_via_downcast	185 ns	157.2 ns	+17.67%
⚡	sequence_from_list	355.6 ns	300 ns	+18.52%
⚡	mapping_from_dict	327.8 ns	272.2 ns	+20.41%
⚡	not_a_list_via_downcast	242.8 ns	215 ns	+12.92%

[davidhewitt]

I suppose the one design question here is whether we think the simpler Bound::from_ptr, Bound::from_ptr_or_opt etc would be better(i.e. dropping the _owned bit).

Nicer names maybe, but they then lose the consistency with Py.

[Icxolu]

I think it makes sense to have these as a complement to the ones on Py. I would suggest to keep the names the same. It's not that much longer to keep _owned and I think its easier to reason about for users if the names are consistent.

I would also suggest to deprecate the corresponding functions on Python, which look like the predecessors of these.

[davidhewitt]

Thanks, that's enough support for me to merge forward with these as-is for now 👍

I would also suggest to deprecate the corresponding functions on Python, which look like the predecessors of these.

Agreed, let me see if I can throw together something for those quickly now...

[davidhewitt]

Agreed, let me see if I can throw together something for those quickly now...

Actually there's still quite a lot of work to migrate off these internally, for now I've just added bullets to #3684 under a deprecations section.