python
diff --git a/‎Lib/tkinter/test/test_tkinter/test_internals.py
Lines changed: 38 additions & 0 deletions b/‎Lib/tkinter/test/test_tkinter/test_internals.py
Lines changed: 38 additions & 0 deletions
diff --git a/‎Modules/_tkinter.c
Lines changed: 3 additions & 3 deletions b/‎Modules/_tkinter.c
Lines changed: 3 additions & 3 deletions
@@ -0,0 +1,38 @@
+import unittest, test.support
+import _tkinter
+import re
+
+class InternalsTest(unittest.TestCase):
+    def assert_raise_on_new(self, tkinter_type):
+        # Users are intentionally prevented from creating new instances of
+        # _tkinter.TkappType, _tkinter.Tcl_Obj and _tkinter.TkttType
+        tkinter_type_name = f'_tkinter.{tkinter_type.__name__}'
+
+        cant_create_message = re.escape(f"cannot create '{tkinter_type_name}' instances")
+        object_message = re.escape(
+            f'object.__new__({tkinter_type_name}) is not safe, '
+            f'use {tkinter_type_name}.__new__()'
+        )
+
+        with self.assertRaisesRegex(TypeError, cant_create_message):
+            tkinter_type()
+        with self.assertRaisesRegex(TypeError, cant_create_message):
+            tkinter_type.__new__(tkinter_type)
+        with self.assertRaisesRegex(TypeError, object_message):
+            object.__new__(tkinter_type)
+
+    def test_tkapp_type_no_instantiation(self):
+        self.assert_raise_on_new(_tkinter.TkappType)
+
+    def test_tck_obj_no_instantiation(self):
+        self.assert_raise_on_new(_tkinter.Tcl_Obj)
+
+    def test_tktt_type_info_no_instantiation(self):
+        self.assert_raise_on_new(_tkinter.TkttType)
+
+
+def test_main():
+    test.support.run_unittest(InternalsTest,)
+
+if __name__ == "__main__":
+    test_main()
@@ -906,6 +906,7 @@ static PyGetSetDef PyTclObject_getsetlist[] = {
 };
 
 static PyType_Slot PyTclObject_Type_slots[] = {
+    {Py_tp_new, PyType_NullNew},
     {Py_tp_dealloc, (destructor)PyTclObject_dealloc},
     {Py_tp_repr, (reprfunc)PyTclObject_repr},
     {Py_tp_str, (reprfunc)PyTclObject_str},
@@ -3206,6 +3207,7 @@ static PyMethodDef Tktt_methods[] =
 };
 
 static PyType_Slot Tktt_Type_slots[] = {
+    {Py_tp_new, PyType_NullNew},
     {Py_tp_dealloc, Tktt_Dealloc},
     {Py_tp_repr, Tktt_Repr},
     {Py_tp_methods, Tktt_methods},
@@ -3261,6 +3263,7 @@ static PyMethodDef Tkapp_methods[] =
 };
 
 static PyType_Slot Tkapp_Type_slots[] = {
+    {Py_tp_new, PyType_NullNew},
     {Py_tp_dealloc, Tkapp_Dealloc},
     {Py_tp_methods, Tkapp_methods},
     {0, 0}
@@ -3459,7 +3462,6 @@ PyInit__tkinter(void)
         Py_DECREF(m);
         return NULL;
     }
-    ((PyTypeObject *)o)->tp_new = NULL;
     if (PyModule_AddObject(m, "TkappType", o)) {
         Py_DECREF(o);
         Py_DECREF(m);
@@ -3472,7 +3474,6 @@ PyInit__tkinter(void)
         Py_DECREF(m);
         return NULL;
     }
-    ((PyTypeObject *)o)->tp_new = NULL;
     if (PyModule_AddObject(m, "TkttType", o)) {
         Py_DECREF(o);
         Py_DECREF(m);
@@ -3485,7 +3486,6 @@ PyInit__tkinter(void)
         Py_DECREF(m);
         return NULL;
     }
-    ((PyTypeObject *)o)->tp_new = NULL;
     if (PyModule_AddObject(m, "Tcl_Obj", o)) {
         Py_DECREF(o);
         Py_DECREF(m);