PyType_FromSpec() is a convenient function to create types dynamically in C extension modules, but its usefulness is limited by the fact that it creates new types using the default metaclass.

I suggest adding a new C API function

PyObject *PyType_FromSpecEx(PyObject *meta, PyType_Spec *spec)

and redefine PyType_FromSpec() as

PyType_FromSpecEx((PyObject *)&PyType_Type, spec)


This functionality cannot be implemented by user because PyType_FromSpec requires access to private slotoffsets table.

A (trivial) patch attached.