Revert changeset 1f31bf3f76f5 (issue5322) except tests.

Lib/test/test_descr.py

@@ -1662,6 +1662,7 @@ order (MRO) for bases """
         self.assertEqual(b.foo, 3)
         self.assertEqual(b.__class__, D)
 
+    @unittest.expectedFailure
     def test_bad_new(self):
         self.assertRaises(TypeError, object.__new__)
         self.assertRaises(TypeError, object.__new__, '')
@@ -1708,6 +1709,7 @@ order (MRO) for bases """
         object.__init__(A(3))
         self.assertRaises(TypeError, object.__init__, A(3), 5)
 
+    @unittest.expectedFailure
     def test_restored_object_new(self):
         class A(object):
             def __new__(cls, *args, **kwargs):

Misc/NEWS

@@ -13,9 +13,6 @@ Core and Builtins
 - Issue #28512: Fixed setting the offset attribute of SyntaxError by
   PyErr_SyntaxLocationEx() and PyErr_SyntaxLocationObject().
 
-- Issue #5322: Fixed setting __new__ to a PyCFunction inside Python code.
-  Original patch by Andreas Stührk.
-
 - Issue #28648: Fixed crash in Py_DecodeLocale() in debug build on Mac OS X
   when decode astral characters.  Patch by Xiang Zhang.
 

Objects/typeobject.c

@@ -6798,34 +6798,7 @@ update_one_slot(PyTypeObject *type, slotdef *p)
                sanity checks and constructing a new argument
                list.  Cut all that nonsense short -- this speeds
                up instance creation tremendously. */
-            PyObject *self = PyCFunction_GET_SELF(descr);
-            if (!self || !PyType_Check(self)) {
-                /* This should never happen because
-                   tp_new_wrapper expects a type for self.
-                   Use slot_tp_new which will call
-                   tp_new_wrapper which will raise an
-                   exception. */
-                specific = (void *)slot_tp_new;
-            }
-            else {
-                PyTypeObject *staticbase;
-                specific = ((PyTypeObject *)self)->tp_new;
-                /* Check that the user does not do anything
-                   silly and unsafe like object.__new__(dict).
-                   To do this, we check that the most derived
-                   base that's not a heap type is this type. */
-                staticbase = type->tp_base;
-                while (staticbase &&
-                       (staticbase->tp_flags & Py_TPFLAGS_HEAPTYPE))
-                    staticbase = staticbase->tp_base;
-                if (staticbase &&
-                    staticbase->tp_new != specific)
-                    /* Seems to be unsafe, better use
-                       slot_tp_new which will call
-                       tp_new_wrapper which will raise an
-                       exception if it is unsafe. */
-                    specific = (void *)slot_tp_new;
-            }
+            specific = (void *)type->tp_new;
             /* XXX I'm not 100% sure that there isn't a hole
                in this reasoning that requires additional
                sanity checks.  I'll buy the first person to