IronPython handles descriptor replacement differently than CPython #843

class SomeDescriptor(object):
    def __get__(self, obj, obj_type=None):
        print('__get__', self, obj, obj_type)
        return self

    def __set__(self, obj, value):
        print('__set__', self, obj, value)
        return self


class Thing(object):
    @property
    def value(self):
        return 123


original_property = Thing.value
Thing.value = SomeDescriptor()
Thing.value = original_property
print(Thing().value)

123

('__set__', <SomeDescriptor object at 0x000000000000006C>, None, <property object at 0x000000000000006D>)
('__get__', <SomeDescriptor object at 0x000000000000006C>, <Thing object at 0x000000000000006E>, <class '__main__.Thing'>)
<SomeDescriptor object at 0x000000000000006C>