bpo-39573: Py_TYPE becomes a static inline function (GH-28128)

Convert the Py_TYPE() and Py_SIZE() macros to static inline
functions. The Py_SET_TYPE() and Py_SET_SIZE() functions must now be
used to set an object type and size.

2 files changed, 38 insertions, 3 deletions

diff --git a/Doc/c-api/structures.rst b/Doc/c-api/structures.rst
index 05c54cc..49f2a61 100644
--- a/Doc/c-api/structures.rst
+++ b/Doc/c-api/structures.rst
@@ -99,7 +99,10 @@ the definition of all other Python objects.
 
    Return a :term:`borrowed reference`.
 
-   The :c:func:`Py_SET_TYPE` function must be used to set an object type.
+   Use the :c:func:`Py_SET_TYPE` function to set an object type.
+
+   .. versionchanged:: 3.11
+      :c:func:`Py_TYPE()` is changed to an inline static function.
 
 
 .. c:function:: int Py_IS_TYPE(PyObject *o, PyTypeObject *type)
@@ -121,9 +124,10 @@ the definition of all other Python objects.
 
    Get the reference count of the Python object *o*.
 
+   Use the :c:func:`Py_SET_REFCNT()` function to set an object reference count.
+
    .. versionchanged:: 3.10
       :c:func:`Py_REFCNT()` is changed to the inline static function.
-      Use :c:func:`Py_SET_REFCNT()` to set an object reference count.
 
 
 .. c:function:: void Py_SET_REFCNT(PyObject *o, Py_ssize_t refcnt)
@@ -137,7 +141,10 @@ the definition of all other Python objects.
 
    Get the size of the Python object *o*.
 
-   The :c:func:`Py_SET_SIZE` function must be used to set an object size.
+   Use the :c:func:`Py_SET_SIZE` function to set an object size.
+
+   .. versionchanged:: 3.11
+      :c:func:`Py_SIZE()` is changed to an inline static function.
 
 
 .. c:function:: void Py_SET_SIZE(PyVarObject *o, Py_ssize_t size)
diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst
index 60ef953..30ee182 100644
--- a/Doc/whatsnew/3.11.rst
+++ b/Doc/whatsnew/3.11.rst
@@ -402,6 +402,34 @@ Porting to Python 3.11
   :ref:`static types <static-types>`.
   (Contributed by Erlend E. Aasland in :issue:`43908`)
 
+* Since :c:func:`Py_TYPE()` is changed to a inline static function,
+  ``Py_TYPE(obj) = new_type`` must be replaced with
+  ``Py_SET_TYPE(obj, new_type)``: see the :c:func:`Py_SET_TYPE()` function
+  (available since Python 3.9). For backward compatibility, this macro can be
+  used::
+
+      #if PY_VERSION_HEX < 0x030900A4 && !defined(Py_SET_TYPE)
+      static inline void _Py_SET_TYPE(PyObject *ob, PyTypeObject *type)
+      { ob->ob_type = type; }
+      #define Py_SET_TYPE(ob, type) _Py_SET_TYPE((PyObject*)(ob), type)
+      #endif
+
+  (Contributed by Victor Stinner in :issue:`39573`.)
+
+* Since :c:func:`Py_SIZE()` is changed to a inline static function,
+  ``Py_SIZE(obj) = new_size`` must be replaced with
+  ``Py_SET_SIZE(obj, new_size)``: see the :c:func:`Py_SET_SIZE()` function
+  (available since Python 3.9). For backward compatibility, this macro can be
+  used::
+
+      #if PY_VERSION_HEX < 0x030900A4 && !defined(Py_SET_SIZE)
+      static inline void _Py_SET_SIZE(PyVarObject *ob, Py_ssize_t size)
+      { ob->ob_size = size; }
+      #define Py_SET_SIZE(ob, size) _Py_SET_SIZE((PyVarObject*)(ob), size)
+      #endif
+
+  (Contributed by Victor Stinner in :issue:`39573`.)
+
 Deprecated
 ----------