[C API] Add PyImport_GetModuleAttrString(mod_name, attr_name) helper function

[vstinner]

Feature or enhancement

Proposal:

Python has an internal _PyImport_GetModuleAttrString(mod_name, attr_name) helper function to import a module and get a module attribute. I propose to make this function public to be able to use it outside Python.

The function is convenient to use and is used by the following files in Python:

• Modules/arraymodule.c
• Modules/cjkcodecs/cjkcodecs.h
• Modules/_ctypes/callbacks.c
• Modules/_datetimemodule.c
• Modules/_decimal/_decimal.c
• Modules/_elementtree.c
• Modules/faulthandler.c
• Modules/_lsprof.c
• Modules/_operator.c
• Modules/_pickle.c
• Modules/posixmodule.c
• Modules/selectmodule.c
• Modules/_sqlite/connection.c
• Modules/_sqlite/module.c
• Modules/_sre/sre.c
• Modules/timemodule.c
• Modules/_zoneinfo.c
• Objects/abstract.c
• Objects/fileobject.c
• Objects/memoryobject.c
• Parser/pegen.c
• Parser/tokenizer/file_tokenizer.c
• Python/import.c
• Python/pylifecycle.c

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

No response

Linked PRs

• gh-128911: Add PyImport_GetModuleAttrString() function #128912
• gh-128911: Add tests on the PyImport C API #128915

[encukou]

IMO, the *String functions should generally have variants that take PyObject*.
So, if we add this we should also add PyImport_GetModuleAttr.

[vstinner]

So, if we add this we should also add PyImport_GetModuleAttr.

Ok, I added PyImport_GetModuleAttr() to my PR.