Fill newly created tuple with Py_None instead of NULL

[sergey-miryanov]

Feature or enhancement

Proposal:

Eventually we can remove NULL checks inside _PyTuple_MaybeUntrack if all created tuples will be well-constructed and contain NULL only if the user is doing something wrong.

cc @markshannon

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• GH-145914: Fill newly created tuple with Py_None instead of NULL #145913

[picnixz]

I would be extra careful here. This is part of the stable ABI and while not explicitly documented, we should be careful that this change won't break downstream. I suggest closing the PR for now and wait for more feedback.

Regarding performances, I don't think it will matter much but I see that for growing tuples, a memset has been replaced by a loop. This may not necessarily be more efficient if we create lots of tuples that are directly discarded or unfilled (though I wonder whether this happens a lot).

[picnixz]

cc @encukou @vstinner @serhiy-storchaka