Function _register_attribute_impl

lib/sqlalchemy/orm/attributes.py:2622–2670

(
    class_: Type[_O],
    key: str,
    uselist: bool = False,
    callable_: Optional[_LoaderCallable] = None,
    useobject: bool = False,
    impl_class: Optional[Type[_AttributeImpl]] = None,
    backref: Optional[str] = None,
    **kw: Any,
)

def _register_attribute_impl(
    class_: Type[_O],
    key: str,
    uselist: bool = False,
    callable_: Optional[_LoaderCallable] = None,
    useobject: bool = False,
    impl_class: Optional[Type[_AttributeImpl]] = None,
    backref: Optional[str] = None,
    **kw: Any,
) -> QueryableAttribute[Any]:
    manager = manager_of_class(class_)
    if uselist:
        factory = kw.pop("typecallable", None)
        typecallable = manager.instrument_collection_class(
            key, factory or list
        )
    else:
        typecallable = kw.pop("typecallable", None)

    dispatch = cast(
        "_Dispatch[QueryableAttribute[Any]]", manager[key].dispatch
    )  # noqa: E501

    impl: _AttributeImpl

    if impl_class:
        # TODO: this appears to be the WriteOnlyAttributeImpl /
        # DynamicAttributeImpl constructor which is hardcoded
        impl = cast("Type[_WriteOnlyAttributeImpl]", impl_class)(
            class_, key, dispatch, **kw
        )
    elif uselist:
        impl = _CollectionAttributeImpl(
            class_, key, callable_, dispatch, typecallable=typecallable, **kw
        )
    elif useobject:
        impl = _ScalarObjectAttributeImpl(
            class_, key, callable_, dispatch, **kw
        )
    else:
        impl = _ScalarAttributeImpl(class_, key, callable_, dispatch, **kw)

    manager[key].impl = impl

    if backref:
        _backref_listeners(manager[key], backref, uselist)

    manager.post_configure_attribute(key)
    return manager[key]


def _register_descriptor(