bpo-42972: Fully support GC protocol for _operator heap types (GH-26371)

Author: Erlend Egeberg Aasland

Modules/_operator.c

@@ -1004,19 +1004,27 @@ itemgetter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
  return (PyObject *)ig;
 }
 
+static int
+itemgetter_clear(itemgetterobject *ig)
+{
+ Py_CLEAR(ig->item);
+ return 0;
+}
+
 static void
 itemgetter_dealloc(itemgetterobject *ig)
 {
  PyTypeObject *tp = Py_TYPE(ig);
  PyObject_GC_UnTrack(ig);
- Py_XDECREF(ig->item);
+ (void)itemgetter_clear(ig);
  tp->tp_free(ig);
  Py_DECREF(tp);
 }
 
 static int
 itemgetter_traverse(itemgetterobject *ig, visitproc visit, void *arg)
 {
+ Py_VISIT(Py_TYPE(ig));
  Py_VISIT(ig->item);
  return 0;
 }
@@ -1113,6 +1121,7 @@ static PyType_Slot itemgetter_type_slots[] = {
  {Py_tp_dealloc, itemgetter_dealloc},
  {Py_tp_call, itemgetter_call},
  {Py_tp_traverse, itemgetter_traverse},
+ {Py_tp_clear, itemgetter_clear},
  {Py_tp_methods, itemgetter_methods},
  {Py_tp_new, itemgetter_new},
  {Py_tp_getattro, PyObject_GenericGetAttr},
@@ -1250,12 +1259,19 @@ attrgetter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
  return (PyObject *)ag;
 }
 
+static int
+attrgetter_clear(attrgetterobject *ag)
+{
+ Py_CLEAR(ag->attr);
+ return 0;
+}
+
 static void
 attrgetter_dealloc(attrgetterobject *ag)
 {
  PyTypeObject *tp = Py_TYPE(ag);
  PyObject_GC_UnTrack(ag);
- Py_XDECREF(ag->attr);
+ (void)attrgetter_clear(ag);
  tp->tp_free(ag);
  Py_DECREF(tp);
 }
@@ -1264,6 +1280,7 @@ static int
 attrgetter_traverse(attrgetterobject *ag, visitproc visit, void *arg)
 {
  Py_VISIT(ag->attr);
+ Py_VISIT(Py_TYPE(ag));
  return 0;
 }
 
@@ -1435,6 +1452,7 @@ static PyType_Slot attrgetter_type_slots[] = {
  {Py_tp_dealloc, attrgetter_dealloc},
  {Py_tp_call, attrgetter_call},
  {Py_tp_traverse, attrgetter_traverse},
+ {Py_tp_clear, attrgetter_clear},
  {Py_tp_methods, attrgetter_methods},
  {Py_tp_new, attrgetter_new},
  {Py_tp_getattro, PyObject_GenericGetAttr},
@@ -1505,23 +1523,32 @@ methodcaller_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
  return (PyObject *)mc;
 }
 
+static int
+methodcaller_clear(methodcallerobject *mc)
+{
+ Py_CLEAR(mc->name);
+ Py_CLEAR(mc->args);
+ Py_CLEAR(mc->kwds);
+ return 0;
+}
+
 static void
 methodcaller_dealloc(methodcallerobject *mc)
 {
  PyTypeObject *tp = Py_TYPE(mc);
  PyObject_GC_UnTrack(mc);
- Py_XDECREF(mc->name);
- Py_XDECREF(mc->args);
- Py_XDECREF(mc->kwds);
+ (void)methodcaller_clear(mc);
  tp->tp_free(mc);
  Py_DECREF(tp);
 }
 
 static int
 methodcaller_traverse(methodcallerobject *mc, visitproc visit, void *arg)
 {
+ Py_VISIT(mc->name);
  Py_VISIT(mc->args);
  Py_VISIT(mc->kwds);
+ Py_VISIT(Py_TYPE(mc));
  return 0;
 }
 
@@ -1680,6 +1707,7 @@ static PyType_Slot methodcaller_type_slots[] = {
  {Py_tp_dealloc, methodcaller_dealloc},
  {Py_tp_call, methodcaller_call},
  {Py_tp_traverse, methodcaller_traverse},
+ {Py_tp_clear, methodcaller_clear},
  {Py_tp_methods, methodcaller_methods},
  {Py_tp_new, methodcaller_new},
  {Py_tp_getattro, PyObject_GenericGetAttr},