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pythongh-105927: Add PyWeakref_GetRef() function (python#105932)
Add tests on PyWeakref_NewRef(), PyWeakref_GetObject(), PyWeakref_GET_OBJECT() and PyWeakref_GetRef().
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‎Doc/c-api/weakref.rst‎

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@@ -11,20 +11,20 @@ simple reference object, and the second acts as a proxy for the original object
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as much as it can.
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.. c:function:: int PyWeakref_Check(ob)
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.. c:function:: int PyWeakref_Check(PyObject *ob)
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Return true if *ob* is either a reference or proxy object. This function
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Return non-zero if *ob* is either a reference or proxy object. This function
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always succeeds.
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.. c:function:: int PyWeakref_CheckRef(ob)
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.. c:function:: int PyWeakref_CheckRef(PyObject *ob)
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Return true if *ob* is a reference object. This function always succeeds.
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Return non-zero if *ob* is a reference object. This function always succeeds.
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.. c:function:: int PyWeakref_CheckProxy(ob)
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.. c:function:: int PyWeakref_CheckProxy(PyObject *ob)
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Return true if *ob* is a proxy object. This function always succeeds.
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Return non-zero if *ob* is a proxy object. This function always succeeds.
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.. c:function:: PyObject* PyWeakref_NewRef(PyObject *ob, PyObject *callback)
@@ -51,10 +51,21 @@ as much as it can.
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``None``, or ``NULL``, this will return ``NULL`` and raise :exc:`TypeError`.
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.. c:function:: int PyWeakref_GetRef(PyObject *ref, PyObject **pobj)
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Get a :term:`strong reference` to the referenced object from a weak
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reference, *ref*, into *\*pobj*.
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Return 0 on success. Raise an exception and return -1 on error.
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If the referent is no longer live, set *\*pobj* to ``NULL`` and return 0.
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.. versionadded:: 3.13
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.. c:function:: PyObject* PyWeakref_GetObject(PyObject *ref)
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Return the referenced object from a weak reference, *ref*. If the referent is
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no longer live, returns :const:`Py_None`.
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Return a :term:`borrowed reference` to the referenced object from a weak
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reference, *ref*. If the referent is no longer live, returns ``Py_None``.
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.. note::
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‎Doc/data/refcounts.dat‎

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@@ -2813,6 +2813,10 @@ PyWeakref_GET_OBJECT:PyObject*:ref:0:
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PyWeakref_GetObject:PyObject*::0:
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PyWeakref_GetObject:PyObject*:ref:0:
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PyWeakref_GetRef:int:::
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PyWeakref_GetRef:PyObject*:ref:0:
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PyWeakref_GetRef:PyObject**:pobj:+1:
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PyWeakref_NewProxy:PyObject*::+1:
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PyWeakref_NewProxy:PyObject*:ob:0:
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PyWeakref_NewProxy:PyObject*:callback:0:

‎Doc/data/stable_abi.dat‎

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‎Doc/whatsnew/3.13.rst‎

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@@ -431,6 +431,10 @@ New Features
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of a :term:`borrowed reference`.
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(Contributed by Victor Stinner in :gh:`105922`.)
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* Add :c:func:`PyWeakref_GetRef` function: similar to
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:c:func:`PyWeakref_GetObject` but returns a :term:`strong reference`, or
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``NULL`` if the referent is no longer live.
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(Contributed by Victor Stinner in :gh:`105927`.)
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Porting to Python 3.13
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----------------------

‎Include/weakrefobject.h‎

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@@ -28,6 +28,7 @@ PyAPI_FUNC(PyObject *) PyWeakref_NewRef(PyObject *ob,
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PyAPI_FUNC(PyObject *) PyWeakref_NewProxy(PyObject *ob,
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PyObject *callback);
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PyAPI_FUNC(PyObject *) PyWeakref_GetObject(PyObject *ref);
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PyAPI_FUNC(int) PyWeakref_GetRef(PyObject *ref, PyObject **pobj);
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#ifndef Py_LIMITED_API

‎Lib/test/test_stable_abi_ctypes.py‎

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‎Misc/NEWS.d/next/C API/2023-06-20-08-59-05.gh-issue-105927.DfGeEA.rst‎

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Add :c:func:`PyWeakref_GetRef` function: similar to
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:c:func:`PyWeakref_GetObject` but returns a :term:`strong reference`, or
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``NULL`` if the referent is no longer live. Patch by Victor Stinner.

‎Misc/stable_abi.toml‎

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@@ -2430,3 +2430,5 @@
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added = '3.12'
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[function.PyImport_AddModuleRef]
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added = '3.13'
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[function.PyWeakref_GetRef]
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added = '3.13'

‎Modules/_testcapimodule.c‎

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@@ -3372,6 +3372,84 @@ check_pyimport_addmodule(PyObject *self, PyObject *args)
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}
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static PyObject *
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test_weakref_capi(PyObject *Py_UNUSED(module), PyObject *Py_UNUSED(args))
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{
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// Create a new heap type, create an instance of this type, and delete the
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// type. This object supports weak references.
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PyObject *new_type = PyObject_CallFunction((PyObject*)&PyType_Type,
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"s(){}", "TypeName");
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if (new_type == NULL) {
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return NULL;
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}
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PyObject *obj = PyObject_CallNoArgs(new_type);
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Py_DECREF(new_type);
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if (obj == NULL) {
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return NULL;
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}
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Py_ssize_t refcnt = Py_REFCNT(obj);
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// test PyWeakref_NewRef(), reference is alive
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PyObject *weakref = PyWeakref_NewRef(obj, NULL);
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if (weakref == NULL) {
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Py_DECREF(obj);
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return NULL;
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}
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assert(PyWeakref_Check(weakref));
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assert(PyWeakref_CheckRefExact(weakref));
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assert(PyWeakref_CheckRefExact(weakref));
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assert(Py_REFCNT(obj) == refcnt);
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// test PyWeakref_GetRef(), reference is alive
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PyObject *ref1;
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assert(PyWeakref_GetRef(weakref, &ref1) == 0);
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assert(ref1 == obj);
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assert(Py_REFCNT(obj) == (refcnt + 1));
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Py_DECREF(ref1);
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// test PyWeakref_GetObject(), reference is alive
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PyObject *ref2 = PyWeakref_GetObject(weakref);
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assert(ref2 == obj);
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// test PyWeakref_GET_OBJECT(), reference is alive
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PyObject *ref3 = PyWeakref_GET_OBJECT(weakref);
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assert(ref3 == obj);
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// delete the referenced object
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assert(Py_REFCNT(obj) == 1);
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Py_DECREF(obj);
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// test PyWeakref_GET_OBJECT(), reference is dead
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assert(PyWeakref_GET_OBJECT(weakref) == Py_None);
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// test PyWeakref_GetRef(), reference is dead
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PyObject *ref4 = Py_True; // marker to check that value was set
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assert(PyWeakref_GetRef(weakref, &ref4) == 0);
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assert(ref4 == NULL);
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// None is not a weak reference object
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PyObject *invalid_weakref = Py_None;
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assert(!PyWeakref_Check(invalid_weakref));
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assert(!PyWeakref_CheckRefExact(invalid_weakref));
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assert(!PyWeakref_CheckRefExact(invalid_weakref));
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// test PyWeakref_GetRef(), invalid type
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assert(!PyErr_Occurred());
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PyObject *ref5 = Py_True; // marker to check that value was set
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assert(PyWeakref_GetRef(invalid_weakref, &ref5) == -1);
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assert(PyErr_ExceptionMatches(PyExc_TypeError));
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PyErr_Clear();
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assert(ref5 == NULL);
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// test PyWeakref_GetObject(), invalid type
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assert(PyWeakref_GetObject(invalid_weakref) == NULL);
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assert(PyErr_ExceptionMatches(PyExc_SystemError));
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PyErr_Clear();
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Py_RETURN_NONE;
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}
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static PyMethodDef TestMethods[] = {
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{"set_errno", set_errno, METH_VARARGS},
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{"test_config", test_config, METH_NOARGS},
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{"function_set_kw_defaults", function_set_kw_defaults, METH_VARARGS, NULL},
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{"test_atexit", test_atexit, METH_NOARGS},
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{"check_pyimport_addmodule", check_pyimport_addmodule, METH_VARARGS},
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{"test_weakref_capi", test_weakref_capi, METH_NOARGS},
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{NULL, NULL} /* sentinel */
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};
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‎Objects/weakrefobject.c‎

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@@ -894,6 +894,24 @@ PyWeakref_NewProxy(PyObject *ob, PyObject *callback)
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}
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int
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PyWeakref_GetRef(PyObject *ref, PyObject **pobj)
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{
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if (ref == NULL) {
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*pobj = NULL;
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PyErr_BadInternalCall();
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return -1;
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}
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if (!PyWeakref_Check(ref)) {
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*pobj = NULL;
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PyErr_SetString(PyExc_TypeError, "expected a weakref");
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return -1;
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}
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*pobj = _PyWeakref_GET_REF(ref);
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return 0;
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}
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PyObject *
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PyWeakref_GetObject(PyObject *ref)
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{

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