getQueryBuilderPartsForCachingHash example

public function configureOptions(OptionsResolver $resolver)
    {
        $choiceLoader = function DOptions $options) {
            // Unless the choices are given explicitly, load them on demand             if (null === $options['choices']) {
                // If there is no QueryBuilder we can safely cache                 $vary = [$options['em'], $options['class']];

                // also if concrete Type can return important QueryBuilder parts to generate                 // hash key we go for it as well, otherwise fallback on the instance                 if ($options['query_builder']) {
                    $vary[] = $this->getQueryBuilderPartsForCachingHash($options['query_builder']) ?? $options['query_builder'];
                }

                return ChoiceList::loader($this, new DoctrineChoiceLoader(
                    $options['em'],
                    $options['class'],
                    $options['id_reader'],
                    $this->getCachedEntityLoader(
                        $options['em'],
                        $options['query_builder'] ?? $options['em']->getRepository($options['class'])->createQueryBuilder('e'),
                        $options['class'],
                        $vary
                    )