I propose adding PyType_GetModuleByDef() to the limited C API version 3.13. The function was added to Python 3.9, the function is now well tested. We could add it way earlier to the limited C API.

cc @encukou

The PyType_GetModuleByDef() function is needed to access the module state in C function which don't get a module as first parameter, but only an instance of a heap type. Heap types should be created with PyType_FromModuleAndSpec(module, spec, bases) to store the module in the type. PyType_GetModuleByDef(type) gives the module and then PyModule_GetState() gives the moulde state.

Examples of functions which don't get a module argument:

• Class methods
• Most slots, examples: tp_new, tp_richcompare, tp_iternext, etc.
• PyGetSetDef getter and setter functions

Without PyType_GetModuleByDef(), many static types cannot be converted to heap types.

The following stdlib extensions use PyType_GetModuleByDef()

Modules/_asynciomodule.c
Modules/_bz2module.c
Modules/_collectionsmodule.c
Modules/_csv.c
Modules/_decimal/_decimal.c
Modules/_elementtree.c
Modules/_functoolsmodule.c
Modules/_io/_iomodule.h
Modules/_pickle.c
Modules/_queuemodule.c
Modules/_randommodule.c
Modules/_sqlite/module.h
Modules/_ssl.c
Modules/_ssl.h
Modules/_struct.c
Modules/_testmultiphase.c
Modules/_threadmodule.c
Modules/_xxinterpchannelsmodule.c
Modules/_zoneinfo.c
Modules/arraymodule.c
Modules/cjkcodecs/multibytecodec.c
Modules/clinic/_testmultiphase.c.h
Modules/itertoolsmodule.c
Modules/socketmodule.c
Python/Python-tokenize.c

Linked PRs

• gh-116936: Add PyType_GetModuleByDef() to the limited C API #116937