gh-94673: Hide Objects in PyTypeObject Behind Accessors (gh-104074)

This makes it much cleaner to move more PyTypeObject fields to PyInterpreterState.

Include/internal/pycore_object.h

@@ -331,10 +331,6 @@ extern int _Py_CheckSlotResult(
     const char *slot_name,
     int success);
 
-// PyType_Ready() must be called if _PyType_IsReady() is false.
-// See also the Py_TPFLAGS_READY flag.
-#define _PyType_IsReady(type) ((type)->tp_dict != NULL)
-
 // Test if a type supports weak references
 static inline int _PyType_SUPPORTS_WEAKREFS(PyTypeObject *type) {
     return (type->tp_weaklistoffset != 0);
@@ -392,8 +388,6 @@ _PyDictOrValues_SetValues(PyDictOrValues *ptr, PyDictValues *values)
 extern PyObject ** _PyObject_ComputedDictPointer(PyObject *);
 extern void _PyObject_FreeInstanceAttributes(PyObject *obj);
 extern int _PyObject_IsInstanceDictEmpty(PyObject *);
-extern int _PyType_HasSubclasses(PyTypeObject *);
-extern PyObject* _PyType_GetSubclasses(PyTypeObject *);
 
 // Access macro to the members which are floating "behind" the object
 static inline PyMemberDef* _PyHeapType_GET_MEMBERS(PyHeapTypeObject *etype) {

Include/internal/pycore_typeobject.h

@@ -109,6 +109,20 @@ extern static_builtin_state * _PyStaticType_GetState(PyInterpreterState *, PyTyp
 extern void _PyStaticType_ClearWeakRefs(PyInterpreterState *, PyTypeObject *type);
 extern void _PyStaticType_Dealloc(PyInterpreterState *, PyTypeObject *);
 
+PyAPI_FUNC(PyObject *) _PyType_GetDict(PyTypeObject *);
+extern PyObject * _PyType_GetBases(PyTypeObject *type);
+extern PyObject * _PyType_GetMRO(PyTypeObject *type);
+extern PyObject* _PyType_GetSubclasses(PyTypeObject *);
+extern int _PyType_HasSubclasses(PyTypeObject *);
+
+// PyType_Ready() must be called if _PyType_IsReady() is false.
+// See also the Py_TPFLAGS_READY flag.
+static inline int
+_PyType_IsReady(PyTypeObject *type)
+{
+    return _PyType_GetDict(type) != NULL;
+}
+
 PyObject *
 _Py_type_getattro_impl(PyTypeObject *type, PyObject *name, int *suppress_missing_attribute);
 PyObject *

Modules/_abc.c

@@ -452,7 +452,8 @@ _abc__abc_init(PyObject *module, PyObject *self)
      * their special status w.r.t. pattern matching. */
     if (PyType_Check(self)) {
         PyTypeObject *cls = (PyTypeObject *)self;
-        PyObject *flags = PyDict_GetItemWithError(cls->tp_dict,
+        PyObject *dict = _PyType_GetDict(cls);
+        PyObject *flags = PyDict_GetItemWithError(dict,
                                                   &_Py_ID(__abc_tpflags__));
         if (flags == NULL) {
             if (PyErr_Occurred()) {
@@ -471,7 +472,7 @@ _abc__abc_init(PyObject *module, PyObject *self)
                 }
                 ((PyTypeObject *)self)->tp_flags |= (val & COLLECTION_FLAGS);
             }
-            if (PyDict_DelItem(cls->tp_dict, &_Py_ID(__abc_tpflags__)) < 0) {
+            if (PyDict_DelItem(dict, &_Py_ID(__abc_tpflags__)) < 0) {
                 return NULL;
             }
         }
@@ -742,7 +743,7 @@ _abc__abc_subclasscheck_impl(PyObject *module, PyObject *self,
     Py_DECREF(ok);
 
     /* 4. Check if it's a direct subclass. */
-    PyObject *mro = ((PyTypeObject *)subclass)->tp_mro;
+    PyObject *mro = _PyType_GetMRO((PyTypeObject *)subclass);
     assert(PyTuple_Check(mro));
     for (pos = 0; pos < PyTuple_GET_SIZE(mro); pos++) {
         PyObject *mro_item = PyTuple_GET_ITEM(mro, pos);

Objects/structseq.c

@@ -26,7 +26,7 @@ const char * const PyStructSequence_UnnamedField = "unnamed field";
 static Py_ssize_t
 get_type_attr_as_size(PyTypeObject *tp, PyObject *name)
 {
-    PyObject *v = PyDict_GetItemWithError(tp->tp_dict, name);
+    PyObject *v = PyDict_GetItemWithError(_PyType_GetDict(tp), name);
     if (v == NULL && !PyErr_Occurred()) {
         PyErr_Format(PyExc_TypeError,
                      "Missed attribute '%U' of type %s",
@@ -493,7 +493,7 @@ initialize_static_type(PyTypeObject *type, PyStructSequence_Desc *desc,
     Py_INCREF(type);
 
     if (initialize_structseq_dict(
-            desc, type->tp_dict, n_members, n_unnamed_members) < 0) {
+            desc, _PyType_GetDict(type), n_members, n_unnamed_members) < 0) {
         Py_DECREF(type);
         return -1;
     }
@@ -549,7 +549,7 @@ _PyStructSequence_InitBuiltinWithFlags(PyInterpreterState *interp,
     }
 
     if (initialize_structseq_dict(
-            desc, type->tp_dict, n_members, n_unnamed_members) < 0) {
+            desc, _PyType_GetDict(type), n_members, n_unnamed_members) < 0) {
         goto error;
     }
 
@@ -675,7 +675,7 @@ _PyStructSequence_NewType(PyStructSequence_Desc *desc, unsigned long tp_flags)
     }
 
     if (initialize_structseq_dict(
-            desc, type->tp_dict, n_members, n_unnamed_members) < 0) {
+            desc, _PyType_GetDict(type), n_members, n_unnamed_members) < 0) {
         Py_DECREF(type);
         return NULL;
     }

Python/context.c

@@ -1309,7 +1309,7 @@ _PyContext_Init(PyInterpreterState *interp)
 
     PyObject *missing = get_token_missing();
     if (PyDict_SetItemString(
-        PyContextToken_Type.tp_dict, "MISSING", missing))
+        _PyType_GetDict(&PyContextToken_Type), "MISSING", missing))
     {
         Py_DECREF(missing);
         return _PyStatus_ERR("can't init context types");