Sonata Admin => Select just the given Discriminator Map type

Question

Subject

When I have a set of entities with a Doctrine Discriminator Map then I cannot add a filter to get just one type of all mapped entities, due SonataAdminBundle and/or SonataDoctrineORMAdminBundle are throwing an error.

Example:

Entities with a Doctrine Discriminator Map

/**
 * @ORM\Table(name="activities")
 * @ORM\Entity()
 * @ORM\InheritanceType("SINGLE_TABLE")
 * @ORM\DiscriminatorColumn(name="type", type="string")
 * @ORM\DiscriminatorMap({
 *     "joined" = "...\JoinedActivity",
 *     "other" = "...\OtherActivity"
 * })
 */
abstract class Activity()
{
    abstract public function getType();
}

/**
 * @ORM\Entity()
 */
class JoinActivity extends Activity()
{
    const TYPE = 'joined';

    public function getType()
    {
        return self::type;
    }
}

/**
 * @ORM\Entity()
 */
class OtherActivity extends Activity()
{
    const TYPE = 'other';

    public function getType()
    {
        return self::type;
    }
}

Then I add the Sonata Admin filter:

protected function configureDatagridFilters(DatagridMapper $filter)
{
    $filter->add(
        'type',
        null,
        [
            'label' => 'Activity Type',
        ],
        'choice',
        [
            'choices' => [
                JoinActivity::TYPE => ucfirst(JoinActivity::TYPE),
                OtherActivity::TYPE => ucfirst(OtherActivity::TYPE),
            ],
        ]
    );
}

Expected results

Get a new filter to select just joined or other activities.

Actual results

Notice: Undefined index: type
500 Internal Server Error - ContextErrorException

Stack trace

As requested by greg0ire this is the Stack Trace returned by Symfony/Sonata:

[1] Symfony\Component\Debug\Exception\ContextErrorException: Notice: Undefined index: type
    at n/a
        in /path/to/symfony/project/vendor/sonata-project/doctrine-orm-admin-bundle/Guesser/FilterTypeGuesser.php line 69

    at Symfony\Component\Debug\ErrorHandler->handleError('8', 'Undefined index: type', '/path/to/symfony/project/vendor/sonata-project/doctrine-orm-admin-bundle/Guesser/FilterTypeGuesser.php', '69', array('class' => 'AppBundle\EntityBundle\Entity\Activity', 'property' => 'type', 'modelManager' => object(ModelManager), 'ret' => array(object(ClassMetadata), 'type', array()), 'options' => array('field_type' => null, 'field_options' => array(), 'options' => array(), 'parent_association_mappings' => array()), 'metadata' => object(ClassMetadata), 'propertyName' => 'type', 'parentAssociationMappings' => array()))
        in /path/to/symfony/project/vendor/sonata-project/doctrine-orm-admin-bundle/Guesser/FilterTypeGuesser.php line 69

    at Sonata\DoctrineORMAdminBundle\Guesser\FilterTypeGuesser->guessType('AppBundle\EntityBundle\Entity\Activity', 'type', object(ModelManager))
        in /path/to/symfony/project/app/cache/dev/classes.php line 15104

    at Sonata\AdminBundle\Guesser\TypeGuesserChain->Sonata\AdminBundle\Guesser\{closure}(object(FilterTypeGuesser))
        in /path/to/symfony/project/app/cache/dev/classes.php line 15111

    at Sonata\AdminBundle\Guesser\TypeGuesserChain->guess(object(Closure))
        in /path/to/symfony/project/app/cache/dev/classes.php line 15105

    at Sonata\AdminBundle\Guesser\TypeGuesserChain->guessType('AppBundle\EntityBundle\Entity\Activity', 'type', object(ModelManager))
        in /path/to/symfony/project/vendor/sonata-project/doctrine-orm-admin-bundle/Builder/DatagridBuilder.php line 105

    at Sonata\DoctrineORMAdminBundle\Builder\DatagridBuilder->addFilter(object(Datagrid), null, object(FieldDescription), object(ActivityAdmin))
        in /path/to/symfony/project/app/cache/dev/classes.php line 13069

    at Sonata\AdminBundle\Datagrid\DatagridMapper->add('type', null, array('label' => 'Activity Type', 'field_options' => array('choices' => array('joined' => 'Joined')), 'field_type' => 'choice', 'field_name' => 'type'), 'choice', array('choices' => array('joined' => 'Joined')))
        in /path/to/symfony/project/src/AppBundle/SonAdminBundle/Admin/ActivityAdmin.php line 64

    at AppBundle\SonAdminBundle\Admin\ActivityAdmin->configureDatagridFilters(object(DatagridMapper))
        in /path/to/symfony/project/app/cache/dev/classes.php line 10609

    at Sonata\AdminBundle\Admin\AbstractAdmin->buildDatagrid()
        in /path/to/symfony/project/app/cache/dev/classes.php line 10910

    at Sonata\AdminBundle\Admin\AbstractAdmin->getDatagrid()
        in /path/to/symfony/project/vendor/sonata-project/admin-bundle/Controller/CRUDController.php line 104

    at Sonata\AdminBundle\Controller\CRUDController->listAction()
        in  line 

    at call_user_func_array(array(object(CRUDController), 'listAction'), array())
        in /path/to/symfony/project/app/bootstrap.php.cache line 3222

    at Symfony\Component\HttpKernel\HttpKernel->handleRaw(object(Request), '1')
        in /path/to/symfony/project/app/bootstrap.php.cache line 3181

    at Symfony\Component\HttpKernel\HttpKernel->handle(object(Request), '1', true)
        in /path/to/symfony/project/app/bootstrap.php.cache line 3335

    at Symfony\Component\HttpKernel\DependencyInjection\ContainerAwareHttpKernel->handle(object(Request), '1', true)
        in /path/to/symfony/project/app/bootstrap.php.cache line 2540

    at Symfony\Component\HttpKernel\Kernel->handle(object(Request))
        in /path/to/symfony/project/web/app_dev.php line 15

    at require('/path/to/symfony/project/web/app_dev.php')
        in /path/to/symfony/project/vendor/symfony/symfony/src/Symfony/Bundle/FrameworkBundle/Resources/config/router_dev.php line 40

Any idea how I can fix it?

Thanks,

Answer 1

It is not recommanded to modify the link between an inherited entity and his superclass once it is created. If you need it, you should consider using composition instead.

That's why Doctrine does not allow to directly manage the discriminator field.

All the following text is copied from this very useful response which is precious for a global and better understanding.

It is not a good sign when the type of an instance of an object needs to change over time. I'm not talking about downcasting/upcasting here, but about the need to change the real type of an object.

First of all, let me tell you why it is a bad idea:

1. A subclass might define more attributes and do some additionnal work in it's constructor. Should we run the new constructor again? What if it overwrites some of our old object's attributes?
2. What if you were working on an instance of that Person in some part of your code, and then it suddenly transforms into an Employee (which might have some redefined behavior you wouldn't expect)?!

That is part of the reason why most languages will not allow you to change the real class type of an object during execution (and memory, of course, but I don't want to get into details). Some let you do that (sometimes in twisted ways, e.g. the JVM), but it's really not good practice!

More often than not, the need to do so lies in bad object-oriented design decisions.

For those reasons, Doctrine will not allow you to change the type of your entity object. Of course, you could write plain SQL (at the end of this post - but please read through!) to do the change anyway, but here's two "clean" options I would suggest:

I realize you've already said the first option wasn't an option but I spent a while writing down this post so I feel like I should make it as complete as possible for future reference.

1. Whenever you need to "change the type" from Person to Employee, create a new instance of the Employee and copy the data you want to copy over from the old Person object to the Employee object. Don't forget to remove the old entity and to persist the new one.
2. Use composition instead of inheritance (see this wiki article for details and links to other articles). EDIT: For the hell of it, here's a part of a nice conversation with Erich Gamma about "Composition over Inheritance"!

See related discussions here and here.

---

Now, here is the plain SQL method I was talking about earlier - I hope you won't need to use it!

Make sure your query is sanitized (as the query will be executed without any verification).

$query = "UPDATE TABLE_NAME_HERE SET discr = 'employee' WHERE id = ".$entity->getId();
$entity_manager->getConnection()->exec( $query );

Here is the documentation and code for the exec method which is in the DBAL\Connection class (for your information):

/**
 * Execute an SQL statement and return the number of affected rows.
 *
 * @param string $statement
 * @return integer The number of affected rows.
 */
public function exec($statement)
{
    $this->connect();
    return $this->_conn->exec($statement);
}

Answer 2

I face the same issue. I did a work around - I use doctrine_orm_callback type with doctrine INSTANCE OF operator.

Code looks like this:

->add('userType',
            'doctrine_orm_callback',
            [
                'callback' => function ($queryBuilder, $alias, $field, $value) {
                    if (!is_array($value) || !array_key_exists('value', $value) || empty($value['value'])) {
                        return false;
                    }

                    $queryBuilder->andWhere($alias . ' INSTANCE OF :userType');
                    $queryBuilder->setParameter('userType', $value['value']);

                    return true;
                },
            ],
            ChoiceType::class,
            [
                'choices' => array_flip(UserType::getChoices()),
                'translation_domain' => $this->getTranslationDomain(),
            ]
        )

And it's working. Maybe it helps you.

Answer 3

I think Sonata is confused b/c it expects type to appear in the fields in your Doctrine mapping. I don't think filtering by type is supporting, but I recall having some support for single inheritance, especially when creating new objects. Can't find it back though.