Method setup_mapping

lib/sqlalchemy/orm/decl_base.py:300–328

(
        cls,
        registry: _RegistryType,
        cls_: Type[_O],
        dict_: _ClassDict,
        table: Optional[FromClause],
        mapper_kw: _MapperKwArgs,
    )

    @classmethod
    def setup_mapping(
        cls,
        registry: _RegistryType,
        cls_: Type[_O],
        dict_: _ClassDict,
        table: Optional[FromClause],
        mapper_kw: _MapperKwArgs,
    ) -> Optional[_MapperConfig]:
        manager = attributes.opt_manager_of_class(cls)
        if manager and manager.class_ is cls_:
            raise exc.InvalidRequestError(
                f"Class {cls!r} already has been instrumented declaratively"
            )

        if cls_.__dict__.get("__abstract__", False):
            return None

        defer_map = _get_immediate_cls_attr(
            cls_, "_sa_decl_prepare_nocascade", strict=True
        ) or hasattr(cls_, "_sa_decl_prepare")

        if defer_map:
            return _DeferredMapperConfig(
                registry, cls_, dict_, table, mapper_kw
            )
        else:
            return _ClassScanMapperConfig(
                registry, cls_, dict_, table, mapper_kw
            )

    def __init__(
        self,