Why in Symfony2 is $form->isValid() returning true, when one of its constraints returns false?
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I have a simple class constraint validator which is referenced correctly in my entity and I can see that it is being called and returning **false** when I validate my form based on the entity, but `$form->isValid()` is returning **true**.

Any idea why this is happening? Surely any constraint returning false should cause the form to be invalid?


Entity:

    * @ACMEAssert\ExampleConstraint()

ACMEConstraint:

<?php


    **
     * @Annotation
     */
    class ExampleConstraint extends Constraint
    {
        public function validatedBy()
        {
            return 'acme.example.validator.example';
        }
    
        public function getTargets()
        {
            return Constraint::CLASS_CONSTRAINT;
        }
    }

ACMEValidator:

    class ExampleValidator extends ConstraintValidator
    {
        public function isValid($entity, Constraint $constraint)
        {
            return false;
        }
    }