bpo-42972: Fully implement GC protocol for xxlimited (GH-26451) (GH-26460)

(cherry picked from commit 4b20f25)

Co-authored-by: Hai Shi <[email protected]>

Co-authored-by: Hai Shi <[email protected]>

Author: miss-islington

Modules/xxlimited.c

@@ -106,6 +106,13 @@ Xxo_traverse(XxoObject *self, visitproc visit, void *arg)
     return 0;
 }
 
+static int
+Xxo_clear(XxoObject *self)
+{
+    Py_CLEAR(self->x_attr);
+    return 0;
+}
+
 static void
 Xxo_finalize(XxoObject *self)
 {
@@ -214,6 +221,7 @@ PyDoc_STRVAR(Xxo_doc,
 static PyType_Slot Xxo_Type_slots[] = {
     {Py_tp_doc, (char *)Xxo_doc},
     {Py_tp_traverse, Xxo_traverse},
+    {Py_tp_clear, Xxo_clear},
     {Py_tp_finalize, Xxo_finalize},
     {Py_tp_dealloc, Xxo_dealloc},
     {Py_tp_getattro, Xxo_getattro},

Modules/xxlimited_35.c

@@ -43,6 +43,13 @@ Xxo_traverse(XxoObject *self, visitproc visit, void *arg)
     return 0;
 }
 
+static int
+Xxo_clear(XxoObject *self)
+{
+    Py_CLEAR(self->x_attr);
+    return 0;
+}
+
 static void
 Xxo_finalize(XxoObject *self)
 {
@@ -108,6 +115,7 @@ Xxo_setattr(XxoObject *self, const char *name, PyObject *v)
 static PyType_Slot Xxo_Type_slots[] = {
     {Py_tp_doc, "The Xxo type"},
     {Py_tp_traverse, Xxo_traverse},
+    {Py_tp_clear, Xxo_clear},
     {Py_tp_finalize, Xxo_finalize},
     {Py_tp_getattro, Xxo_getattro},
     {Py_tp_setattr, Xxo_setattr},