gh-89653: PEP 670: Convert PyCell macros to functions (#92653)

Convert the following macros to static inline functions:

* PyCell_GET()
* PyCell_SET()

Limited C API version 3.12 no longer casts arguments.

Fix also usage of PyCell_SET(): only delete the old value after
setting the new value.

1 files changed, 17 insertions, 2 deletions

diff --git a/Include/cpython/cellobject.h b/Include/cpython/cellobject.h
index e07f9d1..f778f86 100644
--- a/Include/cpython/cellobject.h
+++ b/Include/cpython/cellobject.h
@@ -21,8 +21,23 @@ PyAPI_FUNC(PyObject *) PyCell_New(PyObject *);
 PyAPI_FUNC(PyObject *) PyCell_Get(PyObject *);
 PyAPI_FUNC(int) PyCell_Set(PyObject *, PyObject *);
 
-#define PyCell_GET(op) (((PyCellObject *)(op))->ob_ref)
-#define PyCell_SET(op, v) _Py_RVALUE(((PyCellObject *)(op))->ob_ref = (v))
+static inline PyObject* PyCell_GET(PyObject *op) {
+    assert(PyCell_Check(op));
+    PyCellObject *cell = _Py_CAST(PyCellObject*, op);
+    return cell->ob_ref;
+}
+#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030c0000
+#  define PyCell_GET(op) PyCell_GET(_PyObject_CAST(op))
+#endif
+
+static inline void PyCell_SET(PyObject *op, PyObject *value) {
+    assert(PyCell_Check(op));
+    PyCellObject *cell = _Py_CAST(PyCellObject*, op);
+    cell->ob_ref = value;
+}
+#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 < 0x030c0000
+#  define PyCell_SET(op, value) PyCell_SET(_PyObject_CAST(op), (value))
+#endif
 
 #ifdef __cplusplus
 }