Question

I have this project with an entity A that holds a property b that should be a valid B or null.
B has itself a mandatory property.

How can I assert that b is valid or null? I tried using the Valid assertion, but null is not valid, so it complains about mandatoryItem being null.

<?php 
// use statements

class A
{
    /**
     * @ORM\OneToOne(targetEntity="B")
     * @Assert\Valid
     */
    private b;
}

// meanwhile, in another file...
class B
{
   /**
    * @Assert\NotBlank
    */
   private $mandatoryItem;
}

Answer 1

Before doing anything below make sure you have Assert enabled. If thats already the cause the steps below might be helpful to you.

If you use a form to submit the data and got a formType for that form, but the Valid constraint is not working, you can do this:

Remove the Valid assert.

Inside the AType class buildForm() block you add it like this:

...
$builder->add('B', new BType(), array(
    'required' => false,
));
...

Also in the AType class add this function:

public function setDefaultOptions(OptionsResolverInterface $resolver)
{
    $resolver->setDefaults(array(
        'data_class' => 'Your\AppBundle\Entity\A',
        'cascade_validation' => true,
    ));
}

'cascade_validation' => true, Does the same as Valid but then within the form.