Add typing and collections.abc module prefix

[gentlegiantJGC]

Description

Add typing. and collections.abc prefix to remove ambiguity.

Suggested changelog entry:

Fix typing and collections.abc type hint ambiguity.

[gentlegiantJGC]

The tests need updating to reflect these changes.
Please give an indication if this is something you would consider merging and I will update the tests.

[henryiii]

@InvincibleRMC, thoughts?

[InvincibleRMC]

I think this is a good idea. This was discussed a little in and around #5566 (comment). Adding the module prefix will allow users to create their own Sequence class for example and not have the type hints conflict with typing.Sequence see issues like sizmailov/pybind11-stubgen#241.

[rwgk]

Looks good to me, but do we actually still want to support Python 3.8?

Python 3.8 EOL was 2024-10-07

[rwgk]

Suggestion to make these

PYBIND11_TYPE_HINT_...

so they line up nicely and are easier to pin-point.

[rwgk]

// Python 3.9+ Compatibility

?
(The + is the most important aspect of my suggestion.)

[gentlegiantJGC]

do we actually still want to support Python 3.8?

You still have test runners for 3.8 so I assumed you still supported it.
I couldn't find anything saying what your minimum supported version was.
If you want to drop support then it would simplify this.

[rwgk]

If you want to drop support then it would simplify this.

Me: yes

But I'll go with @henryiii's judgement.

[henryiii]

Let's keep it for 3.0. We can drop it for 3.1.

[henryiii]

I couldn't find anything saying what your minimum supported version was.

It's in setup.cfg (or pyproject.toml after #5598)

[gentlegiantJGC]

I think I am going to scale back this pull request to just adding the module prefix.
Fixing the issue in 3.8 is going to require a lot of changes to the tests which seems pointless for a version that has reached end of life.
I will leave the 3.8 macros but commented out so someone can add them later if they want.

[gentlegiantJGC]

I have fixed the tests.
This only includes adding the module prefixes for typing and collections.abc.
I have no personal interest in supporting Python 3.8 so I will leave that to someone else.
I have left the type hint macros for 3.8 in common.h but commented out to make it easier if someone does want to fix the 3.8 issues. This should just be a case of uncommenting the macros and updating the tests with a switch based on python version.

[henryiii]

If you want it to go into 3.0, 3.8 needs to work (where "work" is very loosely defined as "not be worse that it is now"). If you are fine to wait till after 3.0 (like a week), then no need to worry about 3.8. I'd personally go for the latter.

[gentlegiantJGC]

This can wait for 3.1. I have removed the 3.8 compatibility macros and moved the strings inline.

[gentlegiantJGC]

I don't know why that test is failing

[rwgk]

All tests pass.

@gentlegiantJGC do you want to merge this now (looks good to me)? Or wait until after the v3.0.0 release?

[gentlegiantJGC]

This can't be merged yet because it changes the following which are incompatible with Python 3.8
(typing.)Iterable -> collections.abc.Iterable
(typing.)Iterator -> collections.abc.Iterator
(typing.)Callable -> collections.abc.Callable
(typing.)Sequence -> collections.abc.Sequence

I decided not to support 3.8 because it would make the codebase more complex for something which is getting removed which felt pointless.

[rwgk]

I decided not to support 3.8 because it would make the codebase more complex for something which is getting removed which felt pointless.

Sounds good. I'm just curious: What exactly is incompatible? Certain type checkers when running under 3.8? We're not testing that here? Could/should we?

[henryiii]

Aren't these strings? Those are valid at type-check time, just not turning them into non-string annotations at runtime. I think that's not terrible, though? We might even have examples elsewhere? Our annotations are very much not runnable at runtime already.