Add PyWrapperDescr_Type, allow cls->tp_descr_get, allow overwriting attributes inside PyType_Ready

from_cpython/Include/descrobject.h

@@ -82,6 +82,8 @@ PyAPI_DATA(PyTypeObject) PyGetSetDescr_Type;
 PyAPI_DATA(PyTypeObject) PyMemberDescr_Type;
 #endif
 // (Pyston TODO: add #defines to our names)
+PyAPI_DATA(PyTypeObject*) wrapperdescr_cls;
+#define PyWrapperDescr_Type (*wrapperdescr_cls)
 
 PyAPI_FUNC(PyObject *) PyDescr_NewMethod(PyTypeObject *, PyMethodDef *) PYSTON_NOEXCEPT;
 PyAPI_FUNC(PyObject *) PyDescr_NewClassMethod(PyTypeObject *, PyMethodDef *) PYSTON_NOEXCEPT;

src/capi/typeobject.cpp

@@ -2706,7 +2706,6 @@ extern "C" int PyType_Ready(PyTypeObject* cls) noexcept {
         RELEASE_ASSERT(cls->tp_flags & Py_TPFLAGS_CHECKTYPES, "Pyston doesn't yet support non-checktypes behavior");
     }
 
-    RELEASE_ASSERT(cls->tp_descr_get == NULL, "");
     RELEASE_ASSERT(cls->tp_descr_set == NULL, "");
     RELEASE_ASSERT(cls->tp_free == NULL || cls->tp_free == PyObject_Del || cls->tp_free == PyObject_GC_Del, "");
     RELEASE_ASSERT(cls->tp_is_gc == NULL, "");
@@ -2750,7 +2749,7 @@ extern "C" int PyType_Ready(PyTypeObject* cls) noexcept {
     }
 
     for (PyMethodDef* method = cls->tp_methods; method && method->ml_name; ++method) {
-        cls->giveAttr(method->ml_name, new BoxedMethodDescriptor(method, cls));
+        cls->setattr(method->ml_name, new BoxedMethodDescriptor(method, cls), NULL);
     }
 
     for (PyMemberDef* member = cls->tp_members; member && member->name; ++member) {

src/capi/types.h

@@ -34,7 +34,7 @@ struct wrapper_def {
     // exists in CPython: PyObject *name_strobj
 };
 
-extern BoxedClass* capifunc_cls, *wrapperdescr_cls, *wrapperobject_cls;
+extern "C" BoxedClass* capifunc_cls, *wrapperdescr_cls, *wrapperobject_cls;
 
 class BoxedCApiFunction : public Box {
 private:

src/runtime/capi.cpp

@@ -50,11 +50,10 @@ extern "C" bool _PyObject_CheckBuffer(PyObject* obj) noexcept {
 
 extern "C" {
 int Py_Py3kWarningFlag;
-}
 
 BoxedClass* capifunc_cls;
-
 BoxedClass* wrapperdescr_cls, *wrapperobject_cls;
+}
 
 Box* BoxedWrapperDescriptor::__get__(BoxedWrapperDescriptor* self, Box* inst, Box* owner) {
     RELEASE_ASSERT(self->cls == wrapperdescr_cls, "");

test/test_extension/slots_test.c

@@ -573,6 +573,55 @@ static PyTypeObject slots_tester_nullreturngetattr = {
     0,                                  /* tp_free */
 };
 
+static PyObject* descr_get_func(PyObject* obj, PyObject* inst, PyObject* owner) {
+    printf("Inside descr_get_func:\n");
+    return PyInt_FromLong(42);
+}
+
+static PyTypeObject slots_tester_descrget = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "slots_test.slots_tester_descr_get",            /* tp_name */
+    sizeof(PyObject),          /* tp_basicsize */
+    0,                                  /* tp_itemsize */
+    /* methods */
+    0,                                  /* tp_dealloc */
+    0,                                  /* tp_print */
+    0,                                  /* tp_getattr */
+    0,                                  /* tp_setattr */
+    0,                                  /* tp_compare */
+    0,                                  /* tp_repr */
+    0,                                  /* tp_as_number */
+    0,                                  /* tp_as_sequence */
+    0,                                  /* tp_as_mapping */
+    0,                                  /* tp_hash */
+    0,                                  /* tp_call */
+    0,                                  /* tp_str */
+    PyObject_GenericGetAttr,            /* tp_getattro */
+    0,                                  /* tp_setattro */
+    0,                                  /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT,                 /* tp_flags */
+    0,                                  /* tp_doc */
+    0,                                  /* tp_traverse */
+    0,                                  /* tp_clear */
+    0,                                  /* tp_richcompare */
+    0,                                  /* tp_weaklistoffset */
+    0,                                  /* tp_iter */
+    0,                                  /* tp_iternext */
+    0,                                  /* tp_methods */
+    0,                                  /* tp_members */
+    0,                                  /* tp_getset */
+    0,                                  /* tp_base */
+    0,                                  /* tp_dict */
+    descr_get_func,                     /* tp_descr_get */
+    0,                                  /* tp_descr_set */
+    0,                                  /* tp_dictoffset */
+    0,                                  /* tp_init */
+    0,                                  /* tp_alloc */
+    PyType_GenericNew,                  /* tp_new */
+    0,                                  /* tp_free */
+};
+
+
 // Tests the correctness of the CAPI slots when the attributes get set in Python code:
 static PyObject *
 call_funcs(PyObject* _module, PyObject* args) {
@@ -787,6 +836,10 @@ initslots_test(void)
     res = PyType_Ready(&slots_tester_nullreturngetattr);
     if (res < 0)
         return;
+        
+    res = PyType_Ready(&slots_tester_descrget);
+    if (res < 0)
+        return;
 
     // Not sure if the result of PyInt_FromLong needs to be decref'd
     PyDict_SetItemString(slots_tester_seq.tp_dict, "set_through_tpdict", PyInt_FromLong(123));
@@ -797,4 +850,5 @@ initslots_test(void)
     PyModule_AddObject(m, "SlotsTesterSub", (PyObject *)&slots_tester_sub);
     PyModule_AddObject(m, "SlotsTesterNonsubclassable", (PyObject *)&slots_tester_nonsubclassable);
     PyModule_AddObject(m, "SlotsTesterNullReturnGetAttr", (PyObject *)&slots_tester_nullreturngetattr);
+    PyModule_AddObject(m, "SlotsTesterDescrGet", (PyObject *)&slots_tester_descrget);
 }

test/tests/capi_slots.py

@@ -217,3 +217,8 @@ C.__get__ = lambda *args: None
 slots_test.call_funcs(C())
 del C.__get__
 slots_test.call_funcs(C())
+
+# test if __get__'s called
+class C(object):
+    val = slots_test.SlotsTesterDescrGet()
+print C().val