// properties generated on update can never be updatable...
if ( property.isUpdateable() && generationTiming == GenerationTiming.ALWAYS ) {
	if ( singularAttributeSource.isUpdatable() == null ) {
		// updatable only because the user did not specify
		// anything; just override it
		property.setUpdateable( false );
	}
	else {
		// the user specifically supplied update="true",
		// which constitutes an illegal combo
		throw new MappingException(
			String.format(
				Locale.ENGLISH,
				"Cannot specify both update=\"true\" and generated=\"%s\" for property %s",
				generationTiming.name().toLowerCase(Locale.ROOT),
				propertySource.getName()
			),
			mappingDocument.getOrigin()
		);
	}
}