replace NoExtraItems globals with static singletons and getters

Author: angela-tarantula

Include/internal/pycore_typevarobject.h

@@ -21,8 +21,8 @@ extern int _Py_typing_type_repr(PyUnicodeWriter *, PyObject *);
 extern PyTypeObject _PyTypeAlias_Type;
 extern PyTypeObject _PyNoDefault_Type;
 extern PyObject _Py_NoDefaultStruct;
-extern PyTypeObject _PyNoExtraItems_Type;
-extern PyObject _Py_NoExtraItemsStruct;
+PyAPI_FUNC(PyObject *) _Py_GetNoExtraItemsSingleton(void);
+PyAPI_FUNC(PyTypeObject *) _Py_GetNoExtraItemsType(void);
 
 #ifdef __cplusplus
 }

Modules/_typingmodule.c

@@ -70,7 +70,7 @@ _typing_exec(PyObject *m)
     if (PyModule_AddObjectRef(m, "NoDefault", (PyObject *)&_Py_NoDefaultStruct) < 0) {
         return -1;
     }
-    if (PyModule_AddObjectRef(m, "NoExtraItems", (PyObject *)&_Py_NoExtraItemsStruct) < 0) {
+    if (PyModule_AddObjectRef(m, "NoExtraItems", _Py_GetNoExtraItemsSingleton()) < 0) {
         return -1;
     }
     return 0;

Objects/typevarobject.c

@@ -123,7 +123,10 @@ PyTypeObject _PyNoDefault_Type = {
 
 PyObject _Py_NoDefaultStruct = _PyObject_HEAD_INIT(&_PyNoDefault_Type);
 
-/* NoExtraItems: a marker object for TypeDict extra_items when it's unset. */
+/* NoExtraItems: a marker object for TypedDict extra_items when it's unset. */
+
+static PyTypeObject _PyNoExtraItems_Type;
+static PyObject _Py_NoExtraItemsStruct;
 
 static PyObject *
 NoExtraItems_repr(PyObject *op)
@@ -167,7 +170,7 @@ PyDoc_STRVAR(noextraitems_doc,
 "--\n\n"
 "The type of the NoExtraItems singleton.");
 
-PyTypeObject _PyNoExtraItems_Type = {
+static PyTypeObject _PyNoExtraItems_Type = {
     PyVarObject_HEAD_INIT(&PyType_Type, 0)
     "NoExtraItemsType",
     .tp_dealloc = noextraitems_dealloc,
@@ -178,7 +181,16 @@ PyTypeObject _PyNoExtraItems_Type = {
     .tp_new = noextraitems_new,
 };
 
-PyObject _Py_NoExtraItemsStruct = _PyObject_HEAD_INIT(&_PyNoExtraItems_Type);
+static PyObject _Py_NoExtraItemsStruct = _PyObject_HEAD_INIT(&_PyNoExtraItems_Type);
+
+/* Accessors to avoid exporting global variables. */
+PyObject * _Py_GetNoExtraItemsSingleton(void) {
+    return &_Py_NoExtraItemsStruct;
+}
+
+PyTypeObject * _Py_GetNoExtraItemsType(void) {
+    return &_PyNoExtraItems_Type;
+}
 
 typedef struct {
     PyObject_HEAD