gh-111178: fix UBSan failures in Modules/_functoolsmodule.c (GH-129778)

Fix UBSan failures for `keyobject`, `lru_list_elem`, `lru_cache_object`.
Suppress unused return values.
Change `_PyPartialObject_CAST` (from #124733) to `partialobject_CAST`
for consistency with the current style for these macros

Author: picnixz

Modules/_functoolsmodule.c

@@ -145,7 +145,7 @@ typedef struct {
 } partialobject;
 
 // cast a PyObject pointer PTR to a partialobject pointer (no type checks)
-#define _PyPartialObject_CAST(PTR)  ((partialobject *)(PTR))
+#define partialobject_CAST(op)  ((partialobject *)(op))
 
 static void partial_setvectorcall(partialobject *pto);
 static struct PyModuleDef _functools_module;
@@ -312,7 +312,7 @@ partial_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 static int
 partial_clear(PyObject *self)
 {
-    partialobject *pto = _PyPartialObject_CAST(self);
+    partialobject *pto = partialobject_CAST(self);
     Py_CLEAR(pto->fn);
     Py_CLEAR(pto->args);
     Py_CLEAR(pto->kw);
@@ -323,7 +323,7 @@ partial_clear(PyObject *self)
 static int
 partial_traverse(PyObject *self, visitproc visit, void *arg)
 {
-    partialobject *pto = _PyPartialObject_CAST(self);
+    partialobject *pto = partialobject_CAST(self);
     Py_VISIT(Py_TYPE(pto));
     Py_VISIT(pto->fn);
     Py_VISIT(pto->args);
@@ -338,7 +338,7 @@ partial_dealloc(PyObject *self)
     PyTypeObject *tp = Py_TYPE(self);
     /* bpo-31095: UnTrack is needed before calling any callbacks */
     PyObject_GC_UnTrack(self);
-    if (_PyPartialObject_CAST(self)->weakreflist != NULL) {
+    if (partialobject_CAST(self)->weakreflist != NULL) {
         PyObject_ClearWeakRefs(self);
     }
     (void)partial_clear(self);
@@ -372,7 +372,7 @@ static PyObject *
 partial_vectorcall(PyObject *self, PyObject *const *args,
                    size_t nargsf, PyObject *kwnames)
 {
-    partialobject *pto = _PyPartialObject_CAST(self);;
+    partialobject *pto = partialobject_CAST(self);;
     PyThreadState *tstate = _PyThreadState_GET();
     Py_ssize_t nargs = PyVectorcall_NARGS(nargsf);
 
@@ -482,7 +482,7 @@ partial_setvectorcall(partialobject *pto)
 static PyObject *
 partial_call(PyObject *self, PyObject *args, PyObject *kwargs)
 {
-    partialobject *pto = _PyPartialObject_CAST(self);
+    partialobject *pto = partialobject_CAST(self);
     assert(PyCallable_Check(pto->fn));
     assert(PyTuple_Check(pto->args));
     assert(PyDict_Check(pto->kw));
@@ -595,7 +595,7 @@ static PyGetSetDef partial_getsetlist[] = {
 static PyObject *
 partial_repr(PyObject *self)
 {
-    partialobject *pto = _PyPartialObject_CAST(self);
+    partialobject *pto = partialobject_CAST(self);
     PyObject *result = NULL;
     PyObject *arglist;
     PyObject *mod;
@@ -668,7 +668,7 @@ partial_repr(PyObject *self)
 static PyObject *
 partial_reduce(PyObject *self, PyObject *Py_UNUSED(args))
 {
-    partialobject *pto = _PyPartialObject_CAST(self);
+    partialobject *pto = partialobject_CAST(self);
     return Py_BuildValue("O(O)(OOOO)", Py_TYPE(pto), pto->fn, pto->fn,
                          pto->args, pto->kw,
                          pto->dict ? pto->dict : Py_None);
@@ -677,7 +677,7 @@ partial_reduce(PyObject *self, PyObject *Py_UNUSED(args))
 static PyObject *
 partial_setstate(PyObject *self, PyObject *state)
 {
-    partialobject *pto = _PyPartialObject_CAST(self);
+    partialobject *pto = partialobject_CAST(self);
     PyObject *fn, *fnargs, *kw, *dict;
 
     if (!PyTuple_Check(state)) {
@@ -782,16 +782,19 @@ typedef struct {
     PyObject *object;
 } keyobject;
 
+#define keyobject_CAST(op)  ((keyobject *)(op))
+
 static int
-keyobject_clear(keyobject *ko)
+keyobject_clear(PyObject *op)
 {
+    keyobject *ko = keyobject_CAST(op);
     Py_CLEAR(ko->cmp);
     Py_CLEAR(ko->object);
     return 0;
 }
 
 static void
-keyobject_dealloc(keyobject *ko)
+keyobject_dealloc(PyObject *ko)
 {
     PyTypeObject *tp = Py_TYPE(ko);
     PyObject_GC_UnTrack(ko);
@@ -801,8 +804,9 @@ keyobject_dealloc(keyobject *ko)
 }
 
 static int
-keyobject_traverse(keyobject *ko, visitproc visit, void *arg)
+keyobject_traverse(PyObject *op, visitproc visit, void *arg)
 {
+    keyobject *ko = keyobject_CAST(op);
     Py_VISIT(Py_TYPE(ko));
     Py_VISIT(ko->cmp);
     Py_VISIT(ko->object);
@@ -817,18 +821,18 @@ static PyMemberDef keyobject_members[] = {
 };
 
 static PyObject *
-keyobject_text_signature(PyObject *self, void *Py_UNUSED(ignored))
+keyobject_text_signature(PyObject *Py_UNUSED(self), void *Py_UNUSED(ignored))
 {
     return PyUnicode_FromString("(obj)");
 }
 
 static PyGetSetDef keyobject_getset[] = {
-    {"__text_signature__", keyobject_text_signature, (setter)NULL},
+    {"__text_signature__", keyobject_text_signature, NULL},
     {NULL}
 };
 
 static PyObject *
-keyobject_call(keyobject *ko, PyObject *args, PyObject *kwds);
+keyobject_call(PyObject *ko, PyObject *args, PyObject *kwds);
 
 static PyObject *
 keyobject_richcompare(PyObject *ko, PyObject *other, int op);
@@ -854,11 +858,12 @@ static PyType_Spec keyobject_type_spec = {
 };
 
 static PyObject *
-keyobject_call(keyobject *ko, PyObject *args, PyObject *kwds)
+keyobject_call(PyObject *self, PyObject *args, PyObject *kwds)
 {
     PyObject *object;
     keyobject *result;
     static char *kwargs[] = {"obj", NULL};
+    keyobject *ko = keyobject_CAST(self);
 
     if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:K", kwargs, &object))
         return NULL;
@@ -874,17 +879,20 @@ keyobject_call(keyobject *ko, PyObject *args, PyObject *kwds)
 }
 
 static PyObject *
-keyobject_richcompare(PyObject *ko, PyObject *other, int op)
+keyobject_richcompare(PyObject *self, PyObject *other, int op)
 {
-    if (!Py_IS_TYPE(other, Py_TYPE(ko))) {
+    if (!Py_IS_TYPE(other, Py_TYPE(self))) {
         PyErr_Format(PyExc_TypeError, "other argument must be K instance");
         return NULL;
     }
 
-    PyObject *compare = ((keyobject *) ko)->cmp;
+    keyobject *lhs = keyobject_CAST(self);
+    keyobject *rhs = keyobject_CAST(other);
+
+    PyObject *compare = lhs->cmp;
     assert(compare != NULL);
-    PyObject *x = ((keyobject *) ko)->object;
-    PyObject *y = ((keyobject *) other)->object;
+    PyObject *x = lhs->object;
+    PyObject *y = rhs->object;
     if (!x || !y){
         PyErr_Format(PyExc_AttributeError, "object");
         return NULL;
@@ -1053,9 +1061,12 @@ typedef struct lru_list_elem {
     PyObject *key, *result;
 } lru_list_elem;
 
+#define lru_list_elem_CAST(op)  ((lru_list_elem *)(op))
+
 static void
-lru_list_elem_dealloc(lru_list_elem *link)
+lru_list_elem_dealloc(PyObject *op)
 {
+    lru_list_elem *link = lru_list_elem_CAST(op);
     PyTypeObject *tp = Py_TYPE(link);
     Py_XDECREF(link->key);
     Py_XDECREF(link->result);
@@ -1096,6 +1107,8 @@ typedef struct lru_cache_object {
     PyObject *weakreflist;
 } lru_cache_object;
 
+#define lru_cache_object_CAST(op)   ((lru_cache_object *)(op))
+
 static PyObject *
 lru_cache_make_key(PyObject *kwd_mark, PyObject *args,
                    PyObject *kwds, int typed)
@@ -1531,8 +1544,9 @@ lru_cache_clear_list(lru_list_elem *link)
 }
 
 static int
-lru_cache_tp_clear(lru_cache_object *self)
+lru_cache_tp_clear(PyObject *op)
 {
+    lru_cache_object *self = lru_cache_object_CAST(op);
     lru_list_elem *list = lru_cache_unlink_list(self);
     Py_CLEAR(self->cache);
     Py_CLEAR(self->func);
@@ -1545,23 +1559,25 @@ lru_cache_tp_clear(lru_cache_object *self)
 }
 
 static void
-lru_cache_dealloc(lru_cache_object *obj)
+lru_cache_dealloc(PyObject *op)
 {
+    lru_cache_object *obj = lru_cache_object_CAST(op);
     PyTypeObject *tp = Py_TYPE(obj);
     /* bpo-31095: UnTrack is needed before calling any callbacks */
     PyObject_GC_UnTrack(obj);
     if (obj->weakreflist != NULL) {
-        PyObject_ClearWeakRefs((PyObject*)obj);
+        PyObject_ClearWeakRefs(op);
     }
 
-    (void)lru_cache_tp_clear(obj);
+    (void)lru_cache_tp_clear(op);
     tp->tp_free(obj);
     Py_DECREF(tp);
 }
 
 static PyObject *
-lru_cache_call(lru_cache_object *self, PyObject *args, PyObject *kwds)
+lru_cache_call(PyObject *op, PyObject *args, PyObject *kwds)
 {
+    lru_cache_object *self = lru_cache_object_CAST(op);
     PyObject *result;
     Py_BEGIN_CRITICAL_SECTION(self);
     result = self->wrapper(self, args, kwds);
@@ -1638,8 +1654,9 @@ lru_cache_deepcopy(PyObject *self, PyObject *unused)
 }
 
 static int
-lru_cache_tp_traverse(lru_cache_object *self, visitproc visit, void *arg)
+lru_cache_tp_traverse(PyObject *op, visitproc visit, void *arg)
 {
+    lru_cache_object *self = lru_cache_object_CAST(op);
     Py_VISIT(Py_TYPE(self));
     lru_list_elem *link = self->root.next;
     while (link != &self->root) {
@@ -1827,7 +1844,7 @@ _functools_clear(PyObject *module)
 static void
 _functools_free(void *module)
 {
-    _functools_clear((PyObject *)module);
+    (void)_functools_clear((PyObject *)module);
 }
 
 static struct PyModuleDef_Slot _functools_slots[] = {