[PEP 573] bpo-38787: Module State Access from C Extension Methods

[ghost]

This is a WIP pull request for PEP 573.

The purpose of this PEP is to provide a way to access per-module state from methods belonging to classes defined in extension modules.

https://bugs.python.org/issue38787

[scoder]

Py_XINCREF()?

[scoder]

What is the guarantee that prevents the two tuple item accesses (here and below) from running out of bounds?
Could that be worth a comment, at least?

[encukou]

A for loop might be better: first use PyTuple_Size to also check the type, then use the faster PyTuple_GET_ITEM.

[encukou]

Lots of comments on first glance:

[encukou]

This should be unnecessary.

[encukou]

Can we use the existing PyCFunction_Type for methods?
The METH_METHOD flag should signal that the underlying struct is PyCMethodObject; you'll also want to set tp_itemsize and the use PyObject_GC_NewVar.

[encukou]

This looks unnecessary; the PEP only mentions PyCFunction_GET_CLASS.

[encukou]

Oops, this is missing from the PEP's summary.

[encukou]

This is duplicates the definition in Include/internal/object.h.

[encukou]

This should be much simpler, since PyCFunction_NewEx(...) is defined as PyCMethod_New(..., NULL).

[encukou]

This looks like it would allow (METH_VARARGS | METH_METHOD) or METH_FASTCALL | METH_METHOD

[encukou]

A for loop might be better: first use PyTuple_Size to also check the type, then use the faster PyTuple_GET_ITEM.

[encukou]

Could you also test with another slot, not only __init__?

[encukou]

Is it always named cls?