Why are Symfony2 validation propertyPath valus in square brackets? - symfony

Question

I am validating some values:
$collectionConstraint = new Collection(array(
'email' => array(
new NotBlank(),
new Email(),
),
'password' => array(
new NotBlank(),
new MinLength(array('limit' => 6)),
new MaxLength(array('limit' => 25)),
),
));
$data = array('email' => $this->getRequest()->get('email'), 'password' => $this->getRequest()->get('password'));
$errors = $this->get('validator')->validateValue($data, $collectionConstraint);
But for some reason the fields (propertyPath) are stored with square brackets - I'd like to understand why Sf does that. I have to manually remove all the brackets which seems absurd so I think I am missing some functionality somewhere.
Dump of $errors:
Symfony\Component\Validator\ConstraintViolationList Object
(
[violations:protected] => Array
(
[0] => Symfony\Component\Validator\ConstraintViolation Object
(
[messageTemplate:protected] => This value should not be blank
[messageParameters:protected] => Array
(
)
[root:protected] => Array
(
[email] =>
[password] =>
)
[propertyPath:protected] => [email]
[invalidValue:protected] =>
)
[1] => Symfony\Component\Validator\ConstraintViolation Object
(
[messageTemplate:protected] => This value should not be blank
[messageParameters:protected] => Array
(
)
[root:protected] => Array
(
[email] =>
[password] =>
)
[propertyPath:protected] => [password]
[invalidValue:protected] =>
)
)
)
Even the toString function is useless.
"[email]: This value should not be blank","[password]: This value should not be blank"

Answer 1

Property paths can map either to properties or to indices. Consider a class OptionBag which implements \ArrayAccess and a method getSize().
The property path size refers to $optionBag->getSize()
The property path [size] refers to $optionBag['size']
In your case, you validate an array. Since array elements are also accessed by index, the resulting property path in the violation contains squared brackets.
Update:
You don't have to manually remove the squared brackets. You can use Symfony's PropertyAccess component to map errors to an array with the same structure as your data, for example:
$collectionConstraint = new Collection(array(
'email' => array(
new NotBlank(),
new Email(),
),
'password' => array(
new NotBlank(),
new MinLength(array('limit' => 6)),
new MaxLength(array('limit' => 25)),
),
));
$data = array(
'email' => $this->getRequest()->get('email'),
'password' => $this->getRequest()->get('password')
);
$violations = $this->get('validator')->validateValue($data, $collectionConstraint);
$errors = array();
$accessor = $this->get('property_accessor');
foreach ($violations as $violation) {
$accessor->setValue($errors, $violation->getPropertyPath(), $violation->getMessage());
}
=> array(
'email' => 'This value should not be blank.',
'password' => 'This value should have 6 characters or more.',
)
This also works with multi-dimensional data arrays. There the property paths will be something like [author][name]. The PropertyAccessor will insert the error messages in the same location in the $errors array, i.e. $errors['author']['name'] = 'Message'.

Answer 2

PropertyAccessor's setValue is no real help because it cannot handle multiple violations for a single field. For instance, a field might be shorter than a constraint length and also contain illegal characters. For this, we would have two error messages.
I had to create my own code:
$messages = [];
foreach ($violations as $violation) {
$field = substr($violation->getPropertyPath(), 1, -1);
$messages[] = [$field => $violation->getMessage()];
}
$output = [
'name' => array_unique(array_column($messages, 'name')),
'email' => array_unique(array_column($messages, 'email')),
];
return $output;
We manually strip the [] characters from the property path and create an
array of arrays of fields and corresponding messages. Later we transform the
array to group the messages by fields.
$session = $request->getSession();
$session->getFlashBag()->setAll($messages);
In the controller, we add the messages to the flash bag.