On hold until #27934 is merged. There should be no conflicts with #27931.

This PR will need a rebase after #27934 is merged.

SET_CALLBACK_CONTEXT and CLEAR_CALLBACK_CONTEXT can both be regular functions rather than macros, making them shorter and more readable.
That leaves VISIT_CALLBACK_CONTEXT, which I think is too robust for the 3 uses. But that's very much a personal opinion.

• VISIT_CALLBACK_CONTEXT cannot be implemented as a regular function since it uses Py_VISIT; I prefer to keep the macro
• I'll change CLEAR_CALLBACK_CONTEXT to a regular function; I have no strong opinion about this :)
• SET_CALLBACK_CONTEXT will IMO be more complex as a function, since it would take a pointer to a pointer as an argument; if you have a strong opinion about this, I'll of course change it

NB, this needs to be rebased onto main after #28088 is merged, assuming of course that it'll be easier to land that PR.

will IMO be more complex as a function, since it would take a pointer to a pointer as an argument

Personally I'd prefer a type-safe function with a more complex argument, but as I said, this is nitpicking. Feel free to make them all macros for consistency, if you find it easier to read :)

I plan to review #28088 first.

will IMO be more complex as a function, since it would take a pointer to a pointer as an argument

Personally I'd prefer a type-safe function with a more complex argument, but as I said, this is nitpicking. Feel free to make them all macros for consistency, if you find it easier to read :)

I'll keep VISIT_CALLBACK_CONTEXT function a macro in any case, but I'll think thrice about SET_CALLBACK_CONTEXT before deciding :)

I plan to review #28088 first.

Great, thanks!

BTW, I'm creating a bpo for cleaning up connection __init__; I've got a WIP branch lying around already, so you can expect a PR anytime soon :)

All right, no more changes comin' up, unless you've got further remarks :)

Looks good, thanks!

Likewise!