3.13.2: cast in Py_XDECREF causes runtime failures with immortal objects

Bug report

Bug description:

In Python 3.13.2 I use

Py_XDECREF(PyObject *op) 

It is called at the end of a function-call to load an image (cv2.imread) which fails, resulting in a None value (not NULL!). For Python 3.9 Py_XDECREF works just fine, without crash. For Python 3.13.2 the program, compiled with VS2022 (64 Bit), raises a "Run-Time Check Failure #1 - A cast to a smaller data type has caused a loss of data." and my application crashes ("/RTC1 = Basic Runtime Checks enabled").

I followed up the calls:

    Py_DECREF
        _Py_IsImmortal
            #elif SIZEOF_VOID_P > 4
                _Py_CAST(PY_INT32_T, op->ob_refcnt)     <-- crash

The value is

op->ob_refcnt == 0x0000000100000000

To fix this problem, I propose, that the type cast to 32 bit should be changed to

_Py_CAST(PY_INT32_T, op->ob_refcnt & 0xFFFFFFFF)

CPython versions tested on:

3.13

Operating systems tested on:

Windows

從 Py_XDECREF/Py_DECREF 和 _Py_IsImmortal 的呼叫路徑開始，使用回報的 immortal reference count 重現 Windows VS2022 /RTC1 失敗。將 cast 行為與提議的 masking 進行比較，然後使用相關的 CPython 測試驗證該失敗已獲得解決；該 issue 未指定特定的原始碼檔案或測試。