bpo-39573: Convert Py_TYPE() and Py_SIZE() back to macros (GH-23366)

This change partically reverts
commit ad3252bad905d41635bcbb4b76db30d570cf0087
and the commit fe2978b3b940fe2478335e3a2ca5ad22338cdf9c.

Many third party C extension modules rely on the ability of using
Py_TYPE() to set an object type: "Py_TYPE(obj) = type;" or to set an
object type using: "Py_SIZE(obj) = size;".

1 files changed, 4 insertions, 9 deletions

diff --git a/Include/object.h b/Include/object.h
index dd1b217..f68423a 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -128,16 +128,11 @@ static inline Py_ssize_t _Py_REFCNT(const PyObject *ob) {
 #define Py_REFCNT(ob) _Py_REFCNT(_PyObject_CAST_CONST(ob))
 
 
-static inline Py_ssize_t _Py_SIZE(const PyVarObject *ob) {
-    return ob->ob_size;
-}
-#define Py_SIZE(ob) _Py_SIZE(_PyVarObject_CAST_CONST(ob))
-
+// bpo-39573: The Py_SET_TYPE() function must be used to set an object type.
+#define Py_TYPE(ob)             (_PyObject_CAST(ob)->ob_type)
 
-static inline PyTypeObject* _Py_TYPE(const PyObject *ob) {
-    return ob->ob_type;
-}
-#define Py_TYPE(ob) _Py_TYPE(_PyObject_CAST_CONST(ob))
+// bpo-39573: The Py_SET_SIZE() function must be used to set an object size.
+#define Py_SIZE(ob)             (_PyVarObject_CAST(ob)->ob_size)
 
 
 static inline int _Py_IS_TYPE(const PyObject *ob, const PyTypeObject *type) {