00402: Add PyType_GetDict()

This should make pyqt6 build with Python 3.12.
For more infor see: python#105747

Author: ericsnowcurrently

Doc/c-api/type.rst

@@ -50,6 +50,22 @@ Type Objects
       The return type is now ``unsigned long`` rather than ``long``.
 
 
+.. c:function:: PyObject* PyType_GetDict(PyTypeObject* type)
+
+   Return the type object's internal namespace, which is otherwise only
+   exposed via a read-only proxy (``cls.__dict__``).  This is a
+   replacement for accessing :c:member:`~PyTypeObject.tp_dict` directly.
+   The returned dictionary must be treated as read-only.
+
+   This function isn't intended for general use.  It's meant for
+   specific embedding and language-binding cases, where direct access
+   to the dict is necessary and indirect access (e.g. via the proxy)
+   isn't adequate.  Extension modules may continue to use ``tp_dict``,
+   directly or indirectly, when setting up their own types.
+
+   .. versionadded:: 3.12
+
+
 .. c:function:: void PyType_Modified(PyTypeObject *type)
 
    Invalidate the internal lookup cache for the type and all of its

Doc/c-api/typeobj.rst

@@ -110,7 +110,7 @@ Quick Reference
    +------------------------------------------------+-----------------------------------+-------------------+---+---+---+---+
    | :c:member:`~PyTypeObject.tp_base`              | :c:type:`PyTypeObject` *          | __base__          |   |   | X |   |
    +------------------------------------------------+-----------------------------------+-------------------+---+---+---+---+
-   | :c:member:`~PyTypeObject.tp_dict`              | :c:type:`PyObject` *              | __dict__          |   |   | ? |   |
+   | <<:c:member:`~PyTypeObject.tp_dict`>>          | :c:type:`PyObject` *              | __dict__          |   |   | ? |   |
    +------------------------------------------------+-----------------------------------+-------------------+---+---+---+---+
    | :c:member:`~PyTypeObject.tp_descr_get`         | :c:type:`descrgetfunc`            | __get__           |   |   |   | X |
    +------------------------------------------------+-----------------------------------+-------------------+---+---+---+---+
@@ -157,6 +157,9 @@ Quick Reference
    **<>**: Names in angle brackets should be initially set to ``NULL`` and
    treated as read-only.
 
+   **<<>>**: Names in double angle brackets should be initially set to
+   ``NULL`` and treated as read-only after initialization.
+
    **[]**: Names in square brackets are for internal use only.
 
    **<R>** (as a prefix) means the field is required (must be non-``NULL``).
@@ -1717,7 +1720,17 @@ and :c:type:`PyType_Type` effectively act as defaults.)
    called; it may also be initialized to a dictionary containing initial attributes
    for the type.  Once :c:func:`PyType_Ready` has initialized the type, extra
    attributes for the type may be added to this dictionary only if they don't
-   correspond to overloaded operations (like :meth:`__add__`).
+   correspond to overloaded operations (like :meth:`__add__`).  Once
+   initialization for the type has finished, this field should be
+   treated as read-only.
+
+   .. versionchanged:: 3.12
+
+      Internals detail: For the static builtin types this is always ``NULL``.
+      Instead, the dict for each is stored on ``PyInterpreterState``.
+      If needed, use :c:func:`PyType_GetDict` to get the corresponding
+      dict for those types.  This is not normally necessary,
+      and certainly not for user-defined type objects.
 
    **Inheritance:**
 

Include/cpython/object.h

@@ -283,6 +283,7 @@ PyAPI_FUNC(PyTypeObject *) _PyType_CalculateMetaclass(PyTypeObject *, PyObject *
 PyAPI_FUNC(PyObject *) _PyType_GetDocFromInternalDoc(const char *, const char *);
 PyAPI_FUNC(PyObject *) _PyType_GetTextSignatureFromInternalDoc(const char *, const char *);
 PyAPI_FUNC(PyObject *) PyType_GetModuleByDef(PyTypeObject *, PyModuleDef *);
+PyAPI_FUNC(PyObject *) PyType_GetDict(PyTypeObject *);
 
 PyAPI_FUNC(int) PyObject_Print(PyObject *, FILE *, int);
 PyAPI_FUNC(void) _Py_BreakPoint(void);

Misc/NEWS.d/next/C API/2023-06-13-14-24-55.gh-issue-105227.HDL9aF.rst

@@ -0,0 +1,5 @@
+The new :c:func:`PyType_GetDict` provides the dictionary for the given type
+object that is normally exposed by ``cls.__dict__``.  Normally it's
+sufficient to use :c:member:`~PyTypeObject.tp_dict`, but for the static
+builtin types ``tp_dict`` is now always ``NULL``.  ``PyType_GetDict()``
+provides the correct dict object instead.

Objects/typeobject.c

@@ -238,6 +238,13 @@ _PyType_GetDict(PyTypeObject *self)
     return lookup_tp_dict(self);
 }
 
+PyObject *
+PyType_GetDict(PyTypeObject *self)
+{
+    PyObject *dict = lookup_tp_dict(self);
+    return _Py_XNewRef(dict);
+}
+
 static inline void
 set_tp_dict(PyTypeObject *self, PyObject *dict)
 {