ApiPlatform\Core\Bridge\Doctrine\Orm\Filter\AbstractFilter::getExistingJoin PHP Method

    private function getExistingJoin(QueryBuilder $queryBuilder, string $alias, string $association)
    {
        $parts = $queryBuilder->getDQLPart('join');
        if (!isset($parts['o'])) {
            return;
        }
        foreach ($parts['o'] as $join) {
            if (sprintf('%s.%s', $alias, $association) === $join->getJoin()) {
                return $join;
            }
        }
    }