Omines Datatables - Depth > 2, multiple relation support with orderable/search functionalities

I tried to get this working:

$table = $this->createDataTable()
                ->add('firstname', TextColumn::class, ['label' => 'Vorname', 'orderable'=> true, 'field' => 'personalData.firstname'])
                ->add('lastname', TextColumn::class, ['label' => 'Nachname', 'orderable'=> true, 'field' => 'personalData.lastname'])
                ->add('email', TextColumn::class, ['label' => 'Nachname', 'orderable'=> true, 'field' => 'personalData.lastname'])
                ->add('phone', TextColumn::class, ['label' => 'Telefon', 'orderable'=> true, 'field' => 'personalData.phone'])
                ->add('mobilePhone', TextColumn::class, ['label' => 'Mobil', 'orderable'=> true, 'field' => 'personalData.mobilePhone'])
                ->add('gender', TextColumn::class, ['label' => 'Gender', 'orderable'=> true, 'field' => 'personalData.gender.abbreviation'])
                ->add('lastModified', DateTimeColumn::class, ['label' => 'letzte Änderung', 'orderable'=> true, 'format' => 'd.m.Y H:i:s'])
                ->add('dateCreated', DateTimeColumn::class, ['label' => 'Datum Erstellung', 'orderable'=> true, 'format' => 'd.m.Y H:i:s'])
                ->add('actions', TextColumn::class, ['label' => 'Aktionen', 'orderable'=> false, 'render' => function($value, $context) {
                        $user_id = $context->getId();
                        return sprintf('<button type="button" data-user-id="%s" class="btn btn-primary edit-user-btn"><i class="fas fa-pencil-alt fa-fw fa-fw"></i></button><button type="button" data-user-id="%s" class="btn btn-danger del-user-btn margin-left-10"><i class="fas fa-trash fa-fw fa-fw"></i></button>', $user_id, $user_id);
                    }])
                ->createAdapter(ORMAdapter::class, [
            'entity' => User::class,
        ]);

This results in the following error: Catchable Fatal Error: Object of class App\Entity\Gender could not be converted to string

So as workaround I could add the __toString method to the entity but unfortunately it does not solve the problem so that this column is also orderable.

Then I tried this approach:

$table = $this->createDataTable()
                ->add('firstname', TextColumn::class, ['label' => 'Vorname', 'orderable'=> true, 'field' => 'personalData.firstname'])
                ->add('lastname', TextColumn::class, ['label' => 'Nachname', 'orderable'=> true, 'field' => 'personalData.lastname'])
                ->add('email', TextColumn::class, ['label' => 'Nachname', 'orderable'=> true, 'field' => 'personalData.lastname'])
                ->add('phone', TextColumn::class, ['label' => 'Telefon', 'orderable'=> true, 'field' => 'personalData.phone'])
                ->add('mobilePhone', TextColumn::class, ['label' => 'Mobil', 'orderable'=> true, 'field' => 'personalData.mobilePhone'])
                ->add('gender', TextColumn::class, ['label' => 'Geschlecht', 'orderable'=> true, 'render' => function($value ,$context) {
                        $user_id = $context->getId();

                        $user = $this->getDoctrine()
                                ->getRepository(User::class)
                                ->findOneBy(['id' => $user_id]);

                        return $user->getPersonalData()->getGender()->getAbbreviation();
                    }])
                ->add('lastModified', DateTimeColumn::class, ['label' => 'letzte Änderung', 'orderable'=> true, 'format' => 'd.m.Y H:i:s'])
                ->add('dateCreated', DateTimeColumn::class, ['label' => 'Datum Erstellung', 'orderable'=> true, 'format' => 'd.m.Y H:i:s'])
                ->add('actions', TextColumn::class, ['label' => 'Aktionen', 'orderable'=> false, 'render' => function($value, $context) {
                        $user_id = $context->getId();
                        return sprintf('<button type="button" data-user-id="%s" class="btn btn-primary edit-user-btn"><i class="fas fa-pencil-alt fa-fw fa-fw"></i></button><button type="button" data-user-id="%s" class="btn btn-danger del-user-btn margin-left-10"><i class="fas fa-trash fa-fw fa-fw"></i></button>', $user_id, $user_id);
                    }])
                ->createAdapter(ORMAdapter::class, [
            'entity' => User::class,
        ]);

Now I can see the table loading but if I try to order the table I'm getting the following error message:

Doctrine\ORM\Query\QueryException:
[Syntax Error] line 0, col -1: Error: Expected Doctrine\ORM\Query\Lexer::T_IDENTIFIER, got end of string.

  at vendor/doctrine/orm/lib/Doctrine/ORM/Query/QueryException.php:54
  at Doctrine\ORM\Query\QueryException::syntaxError('line 0, col -1: Error: Expected Doctrine\\ORM\\Query\\Lexer::T_IDENTIFIER, got end of string.', object(QueryException))
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query/Parser.php:457)
  at Doctrine\ORM\Query\Parser->syntaxError('Doctrine\\ORM\\Query\\Lexer::T_IDENTIFIER')
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query/Parser.php:325)
  at Doctrine\ORM\Query\Parser->match(102)
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query/Parser.php:1022)
  at Doctrine\ORM\Query\Parser->ResultVariable()
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query/Parser.php:1521)
  at Doctrine\ORM\Query\Parser->OrderByItem()
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query/Parser.php:1408)
  at Doctrine\ORM\Query\Parser->OrderByClause()
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query/Parser.php:884)
  at Doctrine\ORM\Query\Parser->SelectStatement()
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query/Parser.php:848)
  at Doctrine\ORM\Query\Parser->QueryLanguage()
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query/Parser.php:261)
  at Doctrine\ORM\Query\Parser->getAST()
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query/Parser.php:360)
  at Doctrine\ORM\Query\Parser->parse()
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query.php:286)
  at Doctrine\ORM\Query->_parse()
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query.php:234)
  at Doctrine\ORM\Query->getResultSetMapping()
     (vendor/doctrine/orm/lib/Doctrine/ORM/AbstractQuery.php:902)
  at Doctrine\ORM\AbstractQuery->iterate(array(), 1)
     (vendor/doctrine/orm/lib/Doctrine/ORM/Query.php:689)
  at Doctrine\ORM\Query->iterate(array(), 1)
     (vendor/omines/datatables-bundle/src/Adapter/Doctrine/ORMAdapter.php:205)
  at Omines\DataTablesBundle\Adapter\Doctrine\ORMAdapter->getResults(object(Query))
     (vendor/omines/datatables-bundle/src/Adapter/AbstractAdapter.php:51)
  at Omines\DataTablesBundle\Adapter\AbstractAdapter->getData(object(DataTableState))
     (vendor/omines/datatables-bundle/src/DataTable.php:372)
  at Omines\DataTablesBundle\DataTable->getResultSet()
     (vendor/omines/datatables-bundle/src/DataTable.php:331)
  at Omines\DataTablesBundle\DataTable->getResponse()
     (src/Controller/UsersController.php:100)
  at App\Controller\UsersController->getUsers(object(Request))
     (vendor/symfony/http-kernel/HttpKernel.php:151)
  at Symfony\Component\HttpKernel\HttpKernel->handleRaw(object(Request), 1)
     (vendor/symfony/http-kernel/HttpKernel.php:68)
  at Symfony\Component\HttpKernel\HttpKernel->handle(object(Request), 1, true)
     (vendor/symfony/http-kernel/Kernel.php:198)
  at Symfony\Component\HttpKernel\Kernel->handle(object(Request))
     (public/index.php:24)

So I have an Entity "User" and this has a relation to the entity "personalData" - in addition "personalData" has a relation to "gender" --> I want to have the gender data displayed in the datatables and keep the order and search functionalities working

Is there any workaround or is this a bug?