Surface multiphase init

[oddbookworm]

Since disabling the GIL on singlephase initialization requires the use of PyUnstable_* calls, I would like to make use of multiphase initialization whenever possible. Here is a tentative implementation for an initial port for pygame.Surface. Note that this is just for moving over to multiphase initialization and has nothing to do with free-threading. This should not affect current behavior in any way to the best of my understanding

[ankith26]

why this change? for now I believe it should still be -1 right?

[oddbookworm]

I’ll double check, but it wouldn’t run for me with -1 because -1 is incompatible with subinterpreters, and multiphase implicitly assumes subinterpreter compat (and I actually forgot to figure out what the actual value should be)

[oddbookworm]

Yeah, that's what I thought

❯ python -c "import pygame"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
    import pygame
  File "C:\Users\andre\Projects\pygame-ce\src_py\__init__.py", line 166, in <module>
    import pygame.display
SystemError: module pygame.surface: m_size may not be negative for multi-phase initialization

[damusss]

Hi Andrew. Could you explain to me what this singlephase/multiphase initialization and subinterpreters thing is about? Or if it's easier, where can I properly read about it? I'm uninformed about the topic.

[oddbookworm]

Hi Andrew. Could you explain to me what this singlephase/multiphase initialization and subinterpreters thing is about? Or if it's easier, where can I properly read about it? I'm uninformed about the topic.

Here’s the pep for multi phase
single phase docs
multi phase docs

the reason I want to make this change is because of free threading. Disabling the GIL at a module level in single phase requires the use of unstable API, which can (and probably will) change on us at some arbitrary Python minor version update. Disabling the GIL at a module level in multi phase is as simple as defining a slot

[oddbookworm]

subinterpreters is another topic. The only reason it’s brought up here is because multiphase makes some assumptions that need to be handled for it

[oddbookworm]

Properly handling subinterpreters should be left off for a future pull