GeezerVison

Description

Fixes #1256

ReferenceTypeNode.refTypeWithCallback, used by weakref.ref(obj, cb) and weakref.proxy(obj, cb), skipped the getWeaklistoffset() check that refType does for a None callback, so dict, list, int, None and other builtin objects got a weak reference. CPython checks _PyType_SUPPORTS_WEAKREFS before it looks at the callback (weakrefobject.c#L405-L415).

getBuiltinTypeWeaklistoffset was also missing collections.deque, array.array, mmap.mmap, _contextvars.Context, _queue.SimpleQueue, _struct.Struct and the typing.TypeVar family. These worked only with a callback, so the check alone would have rejected them. With the entries, they now accept a weak reference without a callback too, as on CPython.

AS-IS

>>> weakref.proxy({}, callback)
<weakproxy at 1415; to 'dict' at 1419>
>>> weakref.ref(None, callback)
<weakref at 1753773164; to 'NoneType' at 1613378103>
>>> weakref.ref(d)   # d = collections.deque()
TypeError: cannot create weak reference to 'collections.deque' object

TO-BE

>>> weakref.proxy({}, callback)
TypeError: cannot create weak reference to 'dict' object
>>> weakref.ref(None, callback)
TypeError: cannot create weak reference to 'NoneType' object
>>> weakref.ref(d)
<weakref at 0x10632dfd0; to 'collections.deque' at 0x106351b70>

(matching CPython)

Changes

• Raise TypeError in refTypeWithCallback when the object's class is a PythonBuiltinClassType with a zero getWeaklistoffset(), as refType does.
• Add deque, array, mmap, Context, SimpleQueue and Struct to getBuiltinTypeWeaklistoffset with their CPython 3.13 offsets, and TypeVar, TypeVarTuple, ParamSpec, ParamSpecArgs and ParamSpecKwargs with the managed weakref offset -32.
• Add test_weakref_with_callback_object_type_support and test_weakref_builtin_types_with_weaklist to tests/test_weakref.py.

Testing

mx python-jvm on darwin-aarch64. tests/test_weakref.py passes (13 tests), and both new tests fail on the unpatched build. The tagged lib-python suites test_weakref, test_weakset, test_typing, test_deque, test_array, test_mmap, test_queue, test_struct, test_context, test_functools, test_re and test_threading_local pass. Over 79 builtin, stdlib and user-defined objects, weakref.ref(obj), weakref.ref(obj, cb) and weakref.proxy(obj, cb) now succeed or raise TypeError exactly as on CPython 3.13.14, apart from a __slots__ = () class and operator.attrgetter, which GraalPy already accepted without a callback.