bpo-40137: Convert _functools module to use PyType_FromModuleAndSpec. (GH-23405)

3 files changed, 255 insertions, 224 deletions

diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
index bee9f9112bf..caeeb2712a1 100644
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -27,8 +27,7 @@ import functools
 
 py_functools = import_helper.import_fresh_module('functools',
                                                  blocked=['_functools'])
-c_functools = import_helper.import_fresh_module('functools',
-                                                fresh=['_functools'])
+c_functools = import_helper.import_fresh_module('functools')
 
 decimal = import_helper.import_fresh_module('decimal', fresh=['_decimal'])
 
diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-11-19-23-12-57.bpo-40137.bihl9O.rst b/Misc/NEWS.d/next/Core and Builtins/2020-11-19-23-12-57.bpo-40137.bihl9O.rst
new file mode 100644
index 00000000000..607fa0ecccf
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-11-19-23-12-57.bpo-40137.bihl9O.rst
@@ -0,0 +1 @@
+Convert functools module to use :c:func:`PyType_FromModuleAndSpec`.
diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index 621b721d011..b121ec7d141 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -24,9 +24,37 @@ typedef struct {
     vectorcallfunc vectorcall;
 } partialobject;
 
-static PyTypeObject partial_type;
+typedef struct _functools_state {
+    /* this object is used delimit args and keywords in the cache keys */
+    PyObject *kwd_mark;
+    PyTypeObject *partial_type;
+    PyTypeObject *keyobject_type;
+    PyTypeObject *lru_list_elem_type;
+} _functools_state;
+
+static inline _functools_state *
+get_functools_state(PyObject *module)
+{
+    void *state = PyModule_GetState(module);
+    assert(state != NULL);
+    return (_functools_state *)state;
+}
 
 static void partial_setvectorcall(partialobject *pto);
+static struct PyModuleDef _functools_module;
+static PyObject *
+partial_call(partialobject *pto, PyObject *args, PyObject *kwargs);
+
+static inline _functools_state *
+get_functools_state_by_type(PyTypeObject *type)
+{
+    PyObject *module = _PyType_GetModuleByDef(type, &_functools_module);
+    if (module == NULL) {
+        return NULL;
+    }
+    _functools_state *state = get_functools_state(module);
+    return state;
+}
 
 static PyObject *
 partial_new(PyTypeObject *type, PyObject *args, PyObject *kw)
@@ -42,7 +70,11 @@ partial_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 
     pargs = pkw = NULL;
     func = PyTuple_GET_ITEM(args, 0);
-    if (Py_IS_TYPE(func, &partial_type) && type == &partial_type) {
+    if (Py_TYPE(func)->tp_call == (ternaryfunc)partial_call) {
+        // The type of "func" might not be exactly the same type object
+        // as "type", but if it is called using partial_call, it must have the
+        // same memory layout (fn, args and kw members).
+        // We can use its underlying function directly and merge the arguments.
         partialobject *part = (partialobject *)func;
         if (part->dict == NULL) {
             pargs = part->args;
@@ -117,6 +149,7 @@ partial_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 static void
 partial_dealloc(partialobject *pto)
 {
+    PyTypeObject *tp = Py_TYPE(pto);
     /* bpo-31095: UnTrack is needed before calling any callbacks */
     PyObject_GC_UnTrack(pto);
     if (pto->weakreflist != NULL)
@@ -125,7 +158,8 @@ partial_dealloc(partialobject *pto)
     Py_XDECREF(pto->args);
     Py_XDECREF(pto->kw);
     Py_XDECREF(pto->dict);
-    Py_TYPE(pto)->tp_free(pto);
+    tp->tp_free(pto);
+    Py_DECREF(tp);
 }
 
 
@@ -294,6 +328,12 @@ static PyMemberDef partial_memberlist[] = {
      "tuple of arguments to future partial calls"},
     {"keywords",        T_OBJECT,       OFF(kw),        READONLY,
      "dictionary of keyword arguments to future partial calls"},
+    {"__weaklistoffset__", T_PYSSIZET,
+     offsetof(partialobject, weakreflist), READONLY},
+    {"__dictoffset__", T_PYSSIZET,
+     offsetof(partialobject, dict), READONLY},
+    {"__vectorcalloffset__", T_PYSSIZET,
+     offsetof(partialobject, vectorcall), READONLY},
     {NULL}  /* Sentinel */
 };
 
@@ -420,49 +460,28 @@ static PyMethodDef partial_methods[] = {
     {NULL,              NULL}           /* sentinel */
 };
 
-static PyTypeObject partial_type = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    "functools.partial",                /* tp_name */
-    sizeof(partialobject),              /* tp_basicsize */
-    0,                                  /* tp_itemsize */
-    /* methods */
-    (destructor)partial_dealloc,        /* tp_dealloc */
-    offsetof(partialobject, vectorcall),/* tp_vectorcall_offset */
-    0,                                  /* tp_getattr */
-    0,                                  /* tp_setattr */
-    0,                                  /* tp_as_async */
-    (reprfunc)partial_repr,             /* tp_repr */
-    0,                                  /* tp_as_number */
-    0,                                  /* tp_as_sequence */
-    0,                                  /* tp_as_mapping */
-    0,                                  /* tp_hash */
-    (ternaryfunc)partial_call,          /* tp_call */
-    0,                                  /* tp_str */
-    PyObject_GenericGetAttr,            /* tp_getattro */
-    PyObject_GenericSetAttr,            /* tp_setattro */
-    0,                                  /* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_BASETYPE |
-        Py_TPFLAGS_HAVE_VECTORCALL,     /* tp_flags */
-    partial_doc,                        /* tp_doc */
-    (traverseproc)partial_traverse,     /* tp_traverse */
-    0,                                  /* tp_clear */
-    0,                                  /* tp_richcompare */
-    offsetof(partialobject, weakreflist),       /* tp_weaklistoffset */
-    0,                                  /* tp_iter */
-    0,                                  /* tp_iternext */
-    partial_methods,                    /* tp_methods */
-    partial_memberlist,                 /* tp_members */
-    partial_getsetlist,                 /* tp_getset */
-    0,                                  /* tp_base */
-    0,                                  /* tp_dict */
-    0,                                  /* tp_descr_get */
-    0,                                  /* tp_descr_set */
-    offsetof(partialobject, dict),      /* tp_dictoffset */
-    0,                                  /* tp_init */
-    0,                                  /* tp_alloc */
-    partial_new,                        /* tp_new */
-    PyObject_GC_Del,                    /* tp_free */
+static PyType_Slot partial_type_slots[] = {
+    {Py_tp_dealloc, partial_dealloc},
+    {Py_tp_repr, partial_repr},
+    {Py_tp_call, partial_call},
+    {Py_tp_getattro, PyObject_GenericGetAttr},
+    {Py_tp_setattro, PyObject_GenericSetAttr},
+    {Py_tp_doc, (void *)partial_doc},
+    {Py_tp_traverse, partial_traverse},
+    {Py_tp_methods, partial_methods},
+    {Py_tp_members, partial_memberlist},
+    {Py_tp_getset, partial_getsetlist},
+    {Py_tp_new, partial_new},
+    {Py_tp_free, PyObject_GC_Del},
+    {0, 0}
+};
+
+static PyType_Spec partial_type_spec = {
+    .name = "functools.partial",
+    .basicsize = sizeof(partialobject),
+    .flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
+             Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_VECTORCALL,
+    .slots = partial_type_slots
 };
 
 
@@ -474,12 +493,21 @@ typedef struct {
     PyObject *object;
 } keyobject;
 
+static int
+keyobject_clear(keyobject *ko)
+{
+    Py_CLEAR(ko->cmp);
+    Py_CLEAR(ko->object);
+    return 0;
+}
+
 static void
 keyobject_dealloc(keyobject *ko)
 {
-    Py_DECREF(ko->cmp);
-    Py_XDECREF(ko->object);
+    PyTypeObject *tp = Py_TYPE(ko);
+    keyobject_clear(ko);
     PyObject_Free(ko);
+    Py_DECREF(tp);
 }
 
 static int
@@ -490,15 +518,6 @@ keyobject_traverse(keyobject *ko, visitproc visit, void *arg)
     return 0;
 }
 
-static int
-keyobject_clear(keyobject *ko)
-{
-    Py_CLEAR(ko->cmp);
-    if (ko->object)
-        Py_CLEAR(ko->object);
-    return 0;
-}
-
 static PyMemberDef keyobject_members[] = {
     {"obj", T_OBJECT,
      offsetof(keyobject, object), 0,
@@ -512,38 +531,22 @@ keyobject_call(keyobject *ko, PyObject *args, PyObject *kwds);
 static PyObject *
 keyobject_richcompare(PyObject *ko, PyObject *other, int op);
 
-static PyTypeObject keyobject_type = {
-    PyVarObject_HEAD_INIT(&PyType_Type, 0)
-    "functools.KeyWrapper",             /* tp_name */
-    sizeof(keyobject),                  /* tp_basicsize */
-    0,                                  /* tp_itemsize */
-    /* methods */
-    (destructor)keyobject_dealloc,      /* tp_dealloc */
-    0,                                  /* tp_vectorcall_offset */
-    0,                                  /* tp_getattr */
-    0,                                  /* tp_setattr */
-    0,                                  /* tp_as_async */
-    0,                                  /* tp_repr */
-    0,                                  /* tp_as_number */
-    0,                                  /* tp_as_sequence */
-    0,                                  /* tp_as_mapping */
-    0,                                  /* tp_hash */
-    (ternaryfunc)keyobject_call,        /* tp_call */
-    0,                                  /* tp_str */
-    PyObject_GenericGetAttr,            /* tp_getattro */
-    0,                                  /* tp_setattro */
-    0,                                  /* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT,                 /* tp_flags */
-    0,                                  /* tp_doc */
-    (traverseproc)keyobject_traverse,   /* tp_traverse */
-    (inquiry)keyobject_clear,           /* tp_clear */
-    keyobject_richcompare,              /* tp_richcompare */
-    0,                                  /* tp_weaklistoffset */
-    0,                                  /* tp_iter */
-    0,                                  /* tp_iternext */
-    0,                                  /* tp_methods */
-    keyobject_members,                  /* tp_members */
-    0,                                  /* tp_getset */
+static PyType_Slot keyobject_type_slots[] = {
+    {Py_tp_dealloc, keyobject_dealloc},
+    {Py_tp_call, keyobject_call},
+    {Py_tp_getattro, PyObject_GenericGetAttr},
+    {Py_tp_traverse, keyobject_traverse},
+    {Py_tp_clear, keyobject_clear},
+    {Py_tp_richcompare, keyobject_richcompare},
+    {Py_tp_members, keyobject_members},
+    {0, 0}
+};
+
+static PyType_Spec keyobject_type_spec = {
+    .name = "functools.KeyWrapper",
+    .basicsize = sizeof(keyobject),
+    .flags = Py_TPFLAGS_DEFAULT,
+    .slots = keyobject_type_slots
 };
 
 static PyObject *
@@ -555,9 +558,11 @@ keyobject_call(keyobject *ko, PyObject *args, PyObject *kwds)
 
     if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:K", kwargs, &object))
         return NULL;
-    result = PyObject_New(keyobject, &keyobject_type);
-    if (!result)
+
+    result = PyObject_New(keyobject, Py_TYPE(ko));
+    if (result == NULL) {
         return NULL;
+    }
     Py_INCREF(ko->cmp);
     result->cmp = ko->cmp;
     Py_INCREF(object);
@@ -575,7 +580,7 @@ keyobject_richcompare(PyObject *ko, PyObject *other, int op)
     PyObject *answer;
     PyObject* stack[2];
 
-    if (!Py_IS_TYPE(other, &keyobject_type)) {
+    if (!Py_IS_TYPE(other, Py_TYPE(ko))) {
         PyErr_Format(PyExc_TypeError, "other argument must be K instance");
         return NULL;
     }
@@ -609,10 +614,13 @@ functools_cmp_to_key(PyObject *self, PyObject *args, PyObject *kwds)
     PyObject *cmp;
     static char *kwargs[] = {"mycmp", NULL};
     keyobject *object;
+    _functools_state *state;
 
     if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:cmp_to_key", kwargs, &cmp))
         return NULL;
-    object = PyObject_New(keyobject, &keyobject_type);
+
+    state = get_functools_state(self);
+    object = PyObject_New(keyobject, state->keyobject_type);
     if (!object)
         return NULL;
     Py_INCREF(cmp);
@@ -729,10 +737,6 @@ iterable is empty.");
 
 */
 
-
-/* this object is used delimit args and keywords in the cache keys */
-static PyObject *kwd_mark = NULL;
-
 struct lru_list_elem;
 struct lru_cache_object;
 
@@ -746,33 +750,23 @@ typedef struct lru_list_elem {
 static void
 lru_list_elem_dealloc(lru_list_elem *link)
 {
+    PyTypeObject *tp = Py_TYPE(link);
     Py_XDECREF(link->key);
     Py_XDECREF(link->result);
     PyObject_Free(link);
+    Py_DECREF(tp);
 }
 
-static PyTypeObject lru_list_elem_type = {
-    PyVarObject_HEAD_INIT(&PyType_Type, 0)
-    "functools._lru_list_elem",         /* tp_name */
-    sizeof(lru_list_elem),              /* tp_basicsize */
-    0,                                  /* tp_itemsize */
-    /* methods */
-    (destructor)lru_list_elem_dealloc,  /* tp_dealloc */
-    0,                                  /* tp_vectorcall_offset */
-    0,                                  /* tp_getattr */
-    0,                                  /* tp_setattr */
-    0,                                  /* tp_as_async */
-    0,                                  /* tp_repr */
-    0,                                  /* tp_as_number */
-    0,                                  /* tp_as_sequence */
-    0,                                  /* tp_as_mapping */
-    0,                                  /* tp_hash */
-    0,                                  /* tp_call */
-    0,                                  /* tp_str */
-    0,                                  /* tp_getattro */
-    0,                                  /* tp_setattro */
-    0,                                  /* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT,                 /* tp_flags */
+static PyType_Slot lru_list_elem_type_slots[] = {
+    {Py_tp_dealloc, lru_list_elem_dealloc},
+    {0, 0}
+};
+
+static PyType_Spec lru_list_elem_type_spec = {
+    .name = "functools._lru_list_elem",
+    .basicsize = sizeof(lru_list_elem),
+    .flags = Py_TPFLAGS_DEFAULT,
+    .slots = lru_list_elem_type_slots
 };
 
 
@@ -792,10 +786,9 @@ typedef struct lru_cache_object {
     PyObject *weakreflist;
 } lru_cache_object;
 
-static PyTypeObject lru_cache_type;
-
 static PyObject *
-lru_cache_make_key(PyObject *args, PyObject *kwds, int typed)
+lru_cache_make_key(_functools_state *state, PyObject *args,
+                   PyObject *kwds, int typed)
 {
     PyObject *key, *keyword, *value;
     Py_ssize_t key_size, pos, key_pos, kwds_size;
@@ -834,8 +827,8 @@ lru_cache_make_key(PyObject *args, PyObject *kwds, int typed)
         PyTuple_SET_ITEM(key, key_pos++, item);
     }
     if (kwds_size) {
-        Py_INCREF(kwd_mark);
-        PyTuple_SET_ITEM(key, key_pos++, kwd_mark);
+        Py_INCREF(state->kwd_mark);
+        PyTuple_SET_ITEM(key, key_pos++, state->kwd_mark);
         for (pos = 0; PyDict_Next(kwds, &pos, &keyword, &value);) {
             Py_INCREF(keyword);
             PyTuple_SET_ITEM(key, key_pos++, keyword);
@@ -879,7 +872,12 @@ infinite_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwd
 {
     PyObject *result;
     Py_hash_t hash;
-    PyObject *key = lru_cache_make_key(args, kwds, self->typed);
+    _functools_state *state;
+    state = get_functools_state_by_type(Py_TYPE(self));
+    if (state == NULL) {
+        return NULL;
+    }
+    PyObject *key = lru_cache_make_key(state, args, kwds, self->typed);
     if (!key)
         return NULL;
     hash = PyObject_Hash(key);
@@ -979,8 +977,13 @@ bounded_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds
     lru_list_elem *link;
     PyObject *key, *result, *testresult;
     Py_hash_t hash;
+    _functools_state *state;
 
-    key = lru_cache_make_key(args, kwds, self->typed);
+    state = get_functools_state_by_type(Py_TYPE(self));
+    if (state == NULL) {
+        return NULL;
+    }
+    key = lru_cache_make_key(state, args, kwds, self->typed);
     if (!key)
         return NULL;
     hash = PyObject_Hash(key);
@@ -1035,7 +1038,7 @@ bounded_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds
     {
         /* Cache is not full, so put the result in a new link */
         link = (lru_list_elem *)PyObject_New(lru_list_elem,
-                                             &lru_list_elem_type);
+                                             state->lru_list_elem_type);
         if (link == NULL) {
             Py_DECREF(key);
             Py_DECREF(result);
@@ -1229,22 +1232,31 @@ lru_cache_clear_list(lru_list_elem *link)
     }
 }
 
+static int
+lru_cache_tp_clear(lru_cache_object *self)
+{
+    lru_list_elem *list = lru_cache_unlink_list(self);
+    Py_CLEAR(self->func);
+    Py_CLEAR(self->cache);
+    Py_CLEAR(self->cache_info_type);
+    Py_CLEAR(self->dict);
+    lru_cache_clear_list(list);
+    return 0;
+}
+
 static void
 lru_cache_dealloc(lru_cache_object *obj)
 {
-    lru_list_elem *list;
+    PyTypeObject *tp = Py_TYPE(obj);
     /* bpo-31095: UnTrack is needed before calling any callbacks */
     PyObject_GC_UnTrack(obj);
-    if (obj->weakreflist != NULL)
+    if (obj->weakreflist != NULL) {
         PyObject_ClearWeakRefs((PyObject*)obj);
+    }
 
-    list = lru_cache_unlink_list(obj);
-    Py_XDECREF(obj->cache);
-    Py_XDECREF(obj->func);
-    Py_XDECREF(obj->cache_info_type);
-    Py_XDECREF(obj->dict);
-    lru_cache_clear_list(list);
-    Py_TYPE(obj)->tp_free(obj);
+    lru_cache_tp_clear(obj);
+    tp->tp_free(obj);
+    Py_DECREF(tp);
 }
 
 static PyObject *
@@ -1323,18 +1335,6 @@ lru_cache_tp_traverse(lru_cache_object *self, visitproc visit, void *arg)
     return 0;
 }
 
-static int
-lru_cache_tp_clear(lru_cache_object *self)
-{
-    lru_list_elem *list = lru_cache_unlink_list(self);
-    Py_CLEAR(self->func);
-    Py_CLEAR(self->cache);
-    Py_CLEAR(self->cache_info_type);
-    Py_CLEAR(self->dict);
-    lru_cache_clear_list(list);
-    return 0;
-}
-
 
 PyDoc_STRVAR(lru_cache_doc,
 "Create a cached callable that wraps another function.\n\
@@ -1366,51 +1366,37 @@ static PyGetSetDef lru_cache_getsetlist[] = {
     {NULL}
 };
 
-static PyTypeObject lru_cache_type = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    "functools._lru_cache_wrapper",     /* tp_name */
-    sizeof(lru_cache_object),           /* tp_basicsize */
-    0,                                  /* tp_itemsize */
-    /* methods */
-    (destructor)lru_cache_dealloc,      /* tp_dealloc */
-    0,                                  /* tp_vectorcall_offset */
-    0,                                  /* tp_getattr */
-    0,                                  /* tp_setattr */
-    0,                                  /* tp_as_async */
-    0,                                  /* tp_repr */
-    0,                                  /* tp_as_number */
-    0,                                  /* tp_as_sequence */
-    0,                                  /* tp_as_mapping */
-    0,                                  /* tp_hash */
-    (ternaryfunc)lru_cache_call,        /* tp_call */
-    0,                                  /* tp_str */
-    0,                                  /* tp_getattro */
-    0,                                  /* tp_setattro */
-    0,                                  /* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE |
-    Py_TPFLAGS_HAVE_GC | Py_TPFLAGS_METHOD_DESCRIPTOR,
-                                        /* tp_flags */
-    lru_cache_doc,                      /* tp_doc */
-    (traverseproc)lru_cache_tp_traverse,/* tp_traverse */
-    (inquiry)lru_cache_tp_clear,        /* tp_clear */
-    0,                                  /* tp_richcompare */
-    offsetof(lru_cache_object, weakreflist),
-                                        /* tp_weaklistoffset */
-    0,                                  /* tp_iter */
-    0,                                  /* tp_iternext */
-    lru_cache_methods,                  /* tp_methods */
-    0,                                  /* tp_members */
-    lru_cache_getsetlist,               /* tp_getset */
-    0,                                  /* tp_base */
-    0,                                  /* tp_dict */
-    lru_cache_descr_get,                /* tp_descr_get */
-    0,                                  /* tp_descr_set */
-    offsetof(lru_cache_object, dict),   /* tp_dictoffset */
-    0,                                  /* tp_init */
-    0,                                  /* tp_alloc */
-    lru_cache_new,                      /* tp_new */
+static PyMemberDef lru_cache_memberlist[] = {
+    {"__dictoffset__", T_PYSSIZET,
+     offsetof(lru_cache_object, dict), READONLY},
+    {"__weaklistoffset__", T_PYSSIZET,
+     offsetof(lru_cache_object, weakreflist), READONLY},
+    {NULL}  /* Sentinel */
+};
+
+static PyType_Slot lru_cache_type_slots[] = {
+    {Py_tp_dealloc, lru_cache_dealloc},
+    {Py_tp_call, lru_cache_call},
+    {Py_tp_doc, (void *)lru_cache_doc},
+    {Py_tp_traverse, lru_cache_tp_traverse},
+    {Py_tp_clear, lru_cache_tp_clear},
+    {Py_tp_methods, lru_cache_methods},
+    {Py_tp_members, lru_cache_memberlist},
+    {Py_tp_getset, lru_cache_getsetlist},
+    {Py_tp_descr_get, lru_cache_descr_get},
+    {Py_tp_new, lru_cache_new},
+    {0, 0}
 };
 
+static PyType_Spec lru_cache_type_spec = {
+    .name = "functools._lru_cache_wrapper",
+    .basicsize = sizeof(lru_cache_object),
+    .flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
+             Py_TPFLAGS_METHOD_DESCRIPTOR,
+    .slots = lru_cache_type_slots
+};
+
+
 /* module level code ********************************************************/
 
 PyDoc_STRVAR(_functools_doc,
@@ -1423,38 +1409,83 @@ static PyMethodDef _functools_methods[] = {
     {NULL,              NULL}           /* sentinel */
 };
 
-static void
-_functools_free(void *m)
-{
-    // FIXME: Do not clear kwd_mark to avoid NULL pointer dereferencing if we have
-    //        other modules instances that could use it. Will fix when PEP-573 land
-    //        and we could move kwd_mark to a per-module state.
-    // Py_CLEAR(kwd_mark);
-}
-
 static int
 _functools_exec(PyObject *module)
 {
-    PyTypeObject *typelist[] = {
-        &partial_type,
-        &lru_cache_type
-    };
-
-    if (!kwd_mark) {
-        kwd_mark = _PyObject_CallNoArg((PyObject *)&PyBaseObject_Type);
-        if (!kwd_mark) {
-            return -1;
-        }
+    _functools_state *state = get_functools_state(module);
+    state->kwd_mark = _PyObject_CallNoArg((PyObject *)&PyBaseObject_Type);
+    if (state->kwd_mark == NULL) {
+        return -1;
     }
 
-    for (size_t i = 0; i < Py_ARRAY_LENGTH(typelist); i++) {
-        if (PyModule_AddType(module, typelist[i]) < 0) {
-            return -1;
-        }
+    state->partial_type = (PyTypeObject *)PyType_FromModuleAndSpec(module,
+        &partial_type_spec, NULL);
+    if (state->partial_type == NULL) {
+        return -1;
     }
+    if (PyModule_AddType(module, state->partial_type) < 0) {
+        return -1;
+    }
+
+    PyObject *lru_cache_type = PyType_FromModuleAndSpec(module,
+        &lru_cache_type_spec, NULL);
+    if (lru_cache_type == NULL) {
+        return -1;
+    }
+    if (PyModule_AddType(module, (PyTypeObject *)lru_cache_type) < 0) {
+        Py_DECREF(lru_cache_type);
+        return -1;
+    }
+
+    state->keyobject_type = (PyTypeObject *)PyType_FromModuleAndSpec(module,
+        &keyobject_type_spec, NULL);
+    if (state->keyobject_type == NULL) {
+        return -1;
+    }
+    if (PyModule_AddType(module, state->keyobject_type) < 0) {
+        return -1;
+    }
+
+    state->lru_list_elem_type = (PyTypeObject *)PyType_FromModuleAndSpec(
+        module, &lru_list_elem_type_spec, NULL);
+    if (state->lru_list_elem_type == NULL) {
+        return -1;
+    }
+    if (PyModule_AddType(module, state->lru_list_elem_type) < 0) {
+        return -1;
+    }
+
     return 0;
 }
 
+static int
+_functools_traverse(PyObject *module, visitproc visit, void *arg)
+{
+    _functools_state *state = get_functools_state(module);
+    Py_VISIT(state->kwd_mark);
+    Py_VISIT(state->partial_type);
+    Py_VISIT(state->keyobject_type);
+    Py_VISIT(state->lru_list_elem_type);
+    return 0;
+}
+
+static int
+_functools_clear(PyObject *module)
+{
+    _functools_state *state = get_functools_state(module);
+    Py_CLEAR(state->kwd_mark);
+    Py_CLEAR(state->partial_type);
+    Py_CLEAR(state->keyobject_type);
+    Py_CLEAR(state->lru_list_elem_type);
+    return 0;
+}
+
+static void
+_functools_free(void *module)
+{
+    _functools_clear((PyObject *)module);
+}
+
 static struct PyModuleDef_Slot _functools_slots[] = {
     {Py_mod_exec, _functools_exec},
     {0, NULL}
@@ -1462,14 +1493,14 @@ static struct PyModuleDef_Slot _functools_slots[] = {
 
 static struct PyModuleDef _functools_module = {
     PyModuleDef_HEAD_INIT,
-    "_functools",
-    _functools_doc,
-    0,
-    _functools_methods,
-    _functools_slots,
-    NULL,
-    NULL,
-    _functools_free,
+    .m_name = "_functools",
+    .m_doc = _functools_doc,
+    .m_size = sizeof(_functools_state),
+    .m_methods = _functools_methods,
+    .m_slots = _functools_slots,
+    .m_traverse = _functools_traverse,
+    .m_clear = _functools_clear,
+    .m_free = _functools_free,
 };
 
 PyMODINIT_FUNC