There is no simple way to clear form collection if form is bound to an object.

[Redigast13]

I use doctrine 2 with ZF2 forms. When I submit a form I bind doctrine entity to the form. Then I set POST data to the form. And if the form is valid I save the data to DB. I think it is a normal way to work with ZF2 forms. I use this code when user wants to update "user" entity.

// $form has form collection "roles"
$form->bind($entity); // $entity->roles is not empty
$form->setData($someData); // $someData['roles'] is empty array
if ($form->isValid()) {
    $form->get('roles')->getCount(); // 2(!) it is not empty!
    saveToDb($entity);
}
return $form;

Do you think that this code is corrrect? No. Because there is a form collection in this form. And $entity has two roles now. And user wants to remove all roles from "user" entity. And this beautiful framework can't clear form collection. (populateValues() does nothing if data is empty https://github.com/zendframework/zf2/blob/master/library/Zend/Form/Element/Collection.php#L199 )

So, what should I do? I should find all form collections in this form and clear this collection in doctrine entity before I bind this entity to the form.

foreach ($form->getFieldsets() as $fieldset) {
    if ($fieldset instanceof Collection) {
        $name = $fieldset->getName();
        if (empty($someData[$name])) {
            $methodName = 'set' . ucfirst($name);
            call_user_func([$entity, $methodName], []);
        }
    }
}
$form->bind($entity); // now $entity->roles is empty
$form->setData($someData); // $someData['roles'] is empty array
if ($form->isValid()) {
    $form->get('roles')->getCount(); // 0
    saveToDb($entity);
}
return $form;

Very elegant! Here is the same issue #4492 . It opened TWO years ago. What happened with ZF2? Is this project dead?

[sandrokeil]

Hello @Redigast13 , I've worked with Doctrine 2 and form collections (fieldsets) and had no issues. Do you use the DoctrineModule\Stdlib\Hydrator\DoctrineObject in your fieldset? Here is a fieldset example. The verifier (Account table) is optional and can be null. Must be defined in your database table. Doctrine does the rest.

    public function init()
    {
        $this->setHydrator(new \DoctrineModule\Stdlib\Hydrator\DoctrineObject($this->getObjectManager(), false));
        // bind entity to form
        $this->setObject(new Bug());

        // some more stuff

        $this->add($this->getElementVerifiedBy());

        parent::init();
    }

    protected function getElementVerifiedBy()
    {
        return array(
            'type' => 'DoctrineORMModule\Form\Element\EntitySelect',
            'name' => 'verifiedBy',
            'attributes' => array('id' => 'verifier',),
            'options' => array(
                'label' => 'verifier',
                'empty_option' => 'Please choose verifier',
                'object_manager' => $this->getObjectManager(),
                'target_class' => 'Account',
                'property' => 'username' // property name for option value
            )
        );
    }

The method $this->getObjectManager()returns an instance of `\Doctrine\Common\Persistence\ObjectManager``.

[Redigast13]

Hello @sandrokeil . Yes, I use DoctrineModule\Stdlib\Hydrator\DoctrineObject. But it is not a fieldset. It is a form collection (Zend\Form\Element\Collection). The problem is that I can't clear collection if there is already some data in the collection. For example:

$form->setData(['roles' => ['admin', 'moderator]]); // form collection "roles" will have two items
$form->setData(['roles' => []]); // form collection "roles" still has two items

It happens bacause of populateValues() method does nothing if data is empty https://github.com/zendframework/zf2/blob/master/library/Zend/Form/Element/Collection.php#L199

In ZF2 if I want to bind an object to the form I should bind it before I set data to the form from $_POST array. In my case the entity object already has some value in collection.
When I do $form->bind($entity) I set some data to the form collection. Then I do $form->setData(['roles' => []]) And form collection still has value.
For example user wants to remove all roles. He removes all roles in the form and submits data. Then he see the form with roles again. This is a problem. So, I have to manually change entity before I bind it to the form (I clear collection in the entity bacause I can't clear it in the form). It is very ugly.

[sandrokeil]

Hmm, but on the form collection element page is a link to the form collections aka fieldsets page. You have 2 entities user and role, which is the same (entity bug and user) from my example above. I think you have to use a form fieldset. The Doctrine form element handles the values.

[Redigast13]

In your example one Bug has one user (verifier), right? In my example one user has many roles.
Zend\Form\Fieldset is just a group of fields.
Zend\Form\Collection extends Zend\Form\Fieldset. In collection I can add and remove elements dynamically. So, I need exactly Zend\Form\Collection because I need to add and remove roles from user.

[sandrokeil]

Yes, you're right. But a bug can have multiple products with select option multiple. With this I can add/remove multiple products from bug. But it's a select element. I've never tried the collection element. Maybe other users can help you.

    protected function getElementProduct()
    {
        return array(
            'type' => 'DoctrineORMModule\Form\Element\EntitySelect',
            'name' => 'product',
            'attributes' => array(
                'id' => 'product',
                'multiple' => true // <-- one or more
            ),
            'options' => array(
                'label' => 'product',
                'empty_option' => 'Please choose product',
                'object_manager' => $this->getObjectManager(),
                'target_class' => 'Product',
                'property' => 'name' // property name for option
            )
        );
    }

[Redigast13]

Anyway thank you. Multiple select will really solve this problem. But it was a simple example. If I had text field or group of fields that should dynamically add or remove then I would need form collection. And it is very sad that ZF2 developers don't solve this issue for two years. (#4492)

[svycka]

this is not fixed after 2 years.. 2.4.0 still have this bug
seems like there is a test for this https://github.com/zendframework/zf2/blob/6002c348ee9ebad645654bfd8e5a4f64b69c5fbe/tests/ZendTest/Form/Element/CollectionTest.php#L933-L948
but it does not fail. @weierophinney maybe you can take a look at this. I think you merged this.

[svycka]

fixed with zendframework/zend-form#14

[write2art]

zendframework/zend-form#14 does not fix the issue, cause it lies deeper, in the Form::prepareBindData() method:

protected function prepareBindData(array $values, array $match)
{
    $data = [];
    foreach ($values as $name => $value) {
        if (!array_key_exists($name, $match)) {
            continue;
        }

        if (is_array($value) && is_array($match[$name])) {
            $data[$name] = $this->prepareBindData($value, $match[$name]);
        } else {
            $data[$name] = $value;
        }
    }
    return $data;
}

$match - is a data came from post. And if it does not contain empty array (which is impossible to accomplish without altering post data manually before $form->setData($post)) the collection will not be cleared.

[svycka]

I think there is one more issue when empty collection is not passed to hydrator so it does not get hydrated.

[write2art]

If an empty array for a collection presents in a post data it hydrates normally, clearing the collection. Given that zendframework/zend-form#14 fix applied.

[svycka]

@write2art would zendframework/zend-form#19 fix your problem?

[write2art]

@svycka nope. As i mentioned before, all data which is not present in post gets filtered in Form::prepareBindData() method.

[svycka]

prepareBindData() descriptions says

Parse filtered values and return only posted fields for binding

so it works correctly I think.

also added test to check your usecase and it seems it passed so what exactly does not work? Maybe my test doesn't cover what you need?