pythongh-123504: Fix reference leak in finalization of _tkinter (python#123505)

Author: ZeroIntensity

Misc/NEWS.d/next/Library/2024-08-30-09-01-35.gh-issue-123504.lJ9_BB.rst

@@ -0,0 +1 @@
+Fixed reference leak in the finalization of :mod:`tkinter`.

Modules/_tkinter.c

@@ -3389,17 +3389,28 @@ DisableEventHook(void)
 #endif
 }
 
+static int
+module_clear(PyObject *mod)
+{
+    Py_CLEAR(Tkinter_TclError);
+    Py_CLEAR(Tkapp_Type);
+    Py_CLEAR(Tktt_Type);
+    Py_CLEAR(PyTclObject_Type);
+    return 0;
+}
+
+static void
+module_free(void *mod)
+{
+    module_clear((PyObject *)mod);
+}
 
 static struct PyModuleDef _tkintermodule = {
     PyModuleDef_HEAD_INIT,
-    "_tkinter",
-    NULL,
-    -1,
-    moduleMethods,
-    NULL,
-    NULL,
-    NULL,
-    NULL
+    .m_name = "_tkinter",
+    .m_methods = moduleMethods,
+    .m_clear = module_clear,
+    .m_free = module_free
 };
 
 PyMODINIT_FUNC