Member CirrusSearch\Maintenance\Validators\MappingValidator::__construct (Index $index, $masterTimeout, $optimizeIndexForExperimentalHighlighter, array $availablePlugins, array $mappingConfig, ?Printer $out=null): this constructor takes way too much arguments - refactor
Class CirrusSearch\Search\Rescore\FunctionScoreDecorator: : find another pattern to deal with this problem and avoid this strong dependency to FunctionScore::addFunction signature.
Member CirrusSearch\SearchConfig::makeId ( $pageId): The indices have to be rebuilt with new id's and we have to know when generating queries if new style id's are being used, or old style. It could plausibly be done with the metastore index, but that seems like overkill because the knowledge is only necessary during transition, and not post-transition. Additionally this function would then need to know the name of the index being queried, and that isn't always known when building.