Function validate_view_definition 

pub async fn validate_view_definition(
    def: &ViewDefinition,
    view: &SqlBatchView,
    factory: &Arc<ViewFactory>,
    runtime: Arc<RuntimeEnv>,
    lake: Arc<DataLakeConnection>,
    session_configurator: Arc<dyn SessionConfigurator>,
) -> Result<(), Error>

Every check runs before a definition’s row is written, in this one function shared by the DDL executor and the registry loader – so a definition the loader would skip can never be accepted at CREATE time in the first place. view must already be the result of build_sql_batch_view over def – constructing it is most of the validation (it plans the extract query and yields the schema every check below inspects). factory is the factory view was built against – every other definition, for the DDL executor, or only the definitions in a strictly lower update_group processed so far, for the registry loader – which the update-group ordering check below reads.