gh-101152: Implement PEP 699 (GH-101193)

Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
Co-authored-by: Ken Jin <kenjin@python.org>

Doc/whatsnew/3.12.rst

@@ -430,6 +430,11 @@ Deprecated
   Before, the Python implementation emitted :exc:`FutureWarning`, and the C
   implementation emitted nothing.
 
+* In accordance with :pep:`699`, the ``ma_version_tag`` field in :c:type:`PyDictObject`
+  is deprecated for extension modules. Accessing this field will generate a compiler
+  warning at compile time. This field will be removed in Python 3.14.
+  (Contributed by Ramvikrams and Kumar Aditya in :gh:`101193`. PEP by Ken Jin.)
+
 
 Pending Removal in Python 3.13
 ------------------------------

Include/cpython/dictobject.h

@@ -16,7 +16,11 @@ typedef struct {
 
     /* Dictionary version: globally unique, value change each time
        the dictionary is modified */
+#ifdef Py_BUILD_CORE       
     uint64_t ma_version_tag;
+#else
+    Py_DEPRECATED(3.12) uint64_t ma_version_tag;
+#endif        
 
     PyDictKeysObject *ma_keys;
 

Misc/NEWS.d/next/Build/2023-01-21-10-31-35.gh-issue-101152.xvM8pL.rst

@@ -0,0 +1,3 @@
+In accordance with :PEP:`699`, the ``ma_version_tag`` field in :c:type:`PyDictObject`
+is deprecated for extension modules. Accessing this field will generate a compiler
+warning at compile time. This field will be removed in Python 3.14.

Modules/_testcapimodule.c

@@ -2148,7 +2148,10 @@ dict_get_version(PyObject *self, PyObject *args)
     if (!PyArg_ParseTuple(args, "O!", &PyDict_Type, &dict))
         return NULL;
 
+    _Py_COMP_DIAG_PUSH
+    _Py_COMP_DIAG_IGNORE_DEPR_DECLS    
     version = dict->ma_version_tag;
+    _Py_COMP_DIAG_POP
 
     static_assert(sizeof(unsigned long long) >= sizeof(version),
                   "version is larger than unsigned long long");