Internal C-API: Proposal to optimize or expand helper methods in pycore_abstract.h

[denizguney]

Feature or enhancement

Proposal:

While reviewing the internal abstract protocols in pycore_abstract.h, I noticed potential areas for improving helper functions and fast-path inline checks for object protocols.

Proposed Improvement:
To enhance readability and performance for internal C-API consumers (such as shared extensions and JIT support), we can refine or add small inline utility checks similar to _PyIndex_Check:

// Example concept for checking or optimizing internal operations
static inline int
_PyIndex_Check(PyObject *obj)
{
    PyNumberMethods *tp_as_number = Py_TYPE(obj)->tp_as_number;
    return (tp_as_number != NULL && tp_as_number->nb_index != NULL);
}

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-157199: Add fast inline _PyMapping_Check to pycore_abstract.h #157200

[skirpichev]

Please try to justify this change, e.g. by some benchmarks.