Modules/_weakref.c: weakref module

Modules/_weakref.c is a thin shell. Almost all logic lives in Objects/weakrefobject.c; this file re-exports a handful of functions as module-level callables, adds _remove_dead_weakref for list cleanup, and registers the module with the interpreter.

Map

C symbol	Lines (approx)	Role	Go equivalent
weakref_getweakrefcount	20-40	Delegates to PyWeakref_GetWeakrefCount	weakref.Getweakrefcount
weakref_getweakrefs	42-65	Delegates to PyWeakref_GetWeakrefs, returns list	weakref.Getweakrefs
weakref_proxy	67-90	Delegates to PyWeakref_NewProxy	weakref.Proxy
weakref_ref	92-115	Delegates to PyWeakref_NewRef	weakref.Ref
_remove_dead_weakref	117-155	Removes a dead ref from a dict by key	weakref.RemoveDeadWeakref
weakref_exec	157-180	Module exec slot, imports ref type from Objects/	module init
_PyWeakref_ModuleDef	182-200	PyModuleDef struct, sets name and methods	module def

Reading

ref and proxy re-exports

The four callables (ref, proxy, getweakrefcount, getweakrefs) each wrap a single PyWeakref_* function from Objects/weakrefobject.c. The wrappers exist only to attach Python-level docstrings and to appear in the module method table. No logic is duplicated.

// CPython: Modules/_weakref.c:67
static PyObject *
weakref_proxy(PyObject *self, PyObject *const *args, Py_ssize_t nargs)
{
    ...
    return PyWeakref_NewProxy(object, callback);
}

_remove_dead_weakref

This function is called by the garbage collector after a referent is collected. It receives a dict and a key, looks up the entry, and removes it only if the stored value is a dead weakref. The conditional check prevents accidental deletion of a live ref that was inserted under the same key after collection.

// CPython: Modules/_weakref.c:117
static PyObject *
_weakref__remove_dead_weakref_impl(PyObject *module,
                                   PyObject *dct, PyObject *key)
{
    if (_PyDict_DelItemIf(dct, key, is_dead_weakref, NULL) < 0) {
        ...
    }
    Py_RETURN_NONE;
}

Module exec slot

CPython 3.12+ uses a multi-phase init (Py_mod_exec) rather than PyInit_*. The exec slot borrows the ref type from the core PyWeakref_RefType and re-exposes it as weakref.ref.

// CPython: Modules/_weakref.c:157
static int
weakref_exec(PyObject *m)
{
    if (PyModule_AddObjectRef(m, "ref",
            (PyObject *)&_PyWeakref_RefType) < 0) {
        return -1;
    }
    return 0;
}

gopy notes

• module/weakref/module.go wraps the same four object-layer functions.
• _remove_dead_weakref maps to a dict DelItemIf helper; gopy uses objects/dict_mutate.go for conditional deletion.
• The module does not own the ref type. That type is defined in objects/ and registered here by reference, matching CPython's pattern.
• Multi-phase init is represented in gopy as a plain ModuleInit function called once at startup; there is no separate exec slot concept yet.