How can I Validate All Children of a Form Collection? - forms

Question

I have spent a long time without making progress on what seems to be a simple problem. I need to allow the user to add up to three references to a form. Each reference will have a name and phone number (two text inputs). I would like to do some simple validation on each one. I have created my ReferenceType and nested it into the main form with the following (note, I created the PhoneNumber validator and added the Null() just for testing):
$builder->add('references', 'collection', array(
'type' => new ReferenceType(),
'by_reference' => false,
'allow_add' => true,
'label' => false,
'required' => false,
'attr' => array('class' => 'reference'),
'options' => array(
'required' => false,
'label' => false,
),
'cascade_validation' => true,
'constraints' => array(
new Null(),
new PhoneNumber(),
)
));
ReferenceType:
$builder->add('name', 'text', array(
'label' => 'Reference',
'required' => false,
'cascade_validation' => true,
'attr' => array(
'placeholder' => 'Name'
)
));
$builder->add('phone', 'text', array(
'label' => false,
'required' => false,
'attr' => array(
'placeholder' => 'Phone Number'
),
'cascade_validation' => true,
'constraints' => array(
new Length(array('max' => 14)),
new PhoneNumber(),
)
));
All of that is quite simple and straight forward. However, I have been unable to get the form to throw an error for any reason related to those references. I use Propel for my ORM and have a lot of validation which works correctly on the main form. These references also display and function correctly except for validation. They are all mapped to one column (references) and I have tried Propel's type="array" as well as defining my own getter and setter which serializes the array of items. The type=array doesn't work at all with the collection, and serializing it seems to work ok.
I have searched SO and symfony.com docs for an answer but have found nothing that would actually cause either name or phone to throw an error. I have tried adding validation to my validation.yml file without success (3 chars only for testing):
references:
- Valid: ~
- Collection:
fields:
name:
- Length:
max: 3
maxMessage: Please limit your reference's name to 3 characters or less.
I'm probably missing something very obvious here, but I can't seem to grasp what. I have also dug through the Profiler and everything appears correct in there as well.
Could any provide hints on things to look for? It seems that creating a new database just for references is a little overkill (they don't need to be searchable or anything). Propel has some information on collections, but it didn't seem to make a difference. Or am I entirely missing the idea here and perhaps I should implement the fields an entirely different way?
Symfony 2.6
Propel 2