Function _add_class

lib/sqlalchemy/orm/clsregistry.py:65–116

Add a class to the _decl_class_registry associated with the given declarative class.

(
    classname: str, cls: Type[_T], decl_class_registry: _ClsRegistryType
)

def _add_class(
    classname: str, cls: Type[_T], decl_class_registry: _ClsRegistryType
) -> None:
    """Add a class to the _decl_class_registry associated with the
    given declarative class.

    """
    if classname in decl_class_registry:
        # class already exists.
        existing = decl_class_registry[classname]
        if not isinstance(existing, _MultipleClassMarker):
            decl_class_registry[classname] = _MultipleClassMarker(
                [cls, cast("Type[Any]", existing)]
            )
    else:
        decl_class_registry[classname] = cls

    try:
        root_module = cast(
            _ModuleMarker, decl_class_registry["_sa_module_registry"]
        )
    except KeyError:
        decl_class_registry["_sa_module_registry"] = root_module = (
            _ModuleMarker("_sa_module_registry", None)
        )

    tokens = cls.__module__.split(".")

    # build up a tree like this:
    # modulename:  myapp.snacks.nuts
    #
    # myapp->snack->nuts->(classes)
    # snack->nuts->(classes)
    # nuts->(classes)
    #
    # this allows partial token paths to be used.
    while tokens:
        token = tokens.pop(0)
        module = root_module.get_module(token)
        for token in tokens:
            module = module.get_module(token)

        try:
            module.add_class(classname, cls)
        except AttributeError as ae:
            if not isinstance(module, _ModuleMarker):
                raise exc.InvalidRequestError(
                    f'name "{classname}" matches both a '
                    "class name and a module name"
                ) from ae
            else:
                raise


def _remove_class(