Element\DateTime construction w/ invalid min / max validation values causes form to not work w/o a clear reason why

[jackdpeterson]

Given the following array notation, the DateTime Element will indicate that the date information provided on submission is invalid. The cause for this is because the Element is presuming that the min / max validators will ALWAYS construct to a \DateTime object; however, in this case they return to null because the format is not compliant with the expected constant's string.

[
    'spec' => [
        'name' => 'start_time',
        'type' => Zend\Form\Element\DateTime::class,
        'options' => [
            'label' => 'Appointment Date',
        ],
        'attributes' => [
            'min' => '2017-01-01',
            'max' => '2017-12-29',
            'step' => 1,
        ],
    ],
]

The following spec does work:

[
    'spec' => [
        'name' => 'start_time',
        'type' => Zend\Form\Element\DateTime::class,
        'options' => [
            'label' => 'Appointment Date',
        ],
        'attributes' => [
            'min' => '2017-01-01T00:00+00:00',
            'max' => '2017-12-29T23:59+00:00',
            'step' => 1,
        ],
    ],
]

[jackdpeterson]

Stack trace one one gets through submission would look something like this:

#0 vendor\/zendframework\/zend-validator\/src\/ValidatorChain.php(246): Zend\\Validator\\DateStep->isValid('2017-01-01T09:0...', Array)\n
#1 vendor\/zendframework\/zend-inputfilter\/src\/Input.php(434): Zend\\Validator\\ValidatorChain->isValid('2017-01-01T09:0...', Array)\n
#2 vendor\/zendframework\/zend-inputfilter\/src\/BaseInputFilter.php(259): Zend\\InputFilter\\Input->isValid(Array)\n
#3 vendor\/zendframework\/zend-inputfilter\/src\/BaseInputFilter.php(213): Zend\\InputFilter\\BaseInputFilter->validateInputs(Array, Array, NULL)\n
#4 vendor\/zendframework\/zend-inputfilter\/src\/BaseInputFilter.php(237): Zend\\InputFilter\\BaseInputFilter->isValid(NULL)\n
#5 vendor\/zendframework\/zend-inputfilter\/src\/BaseInputFilter.php(213): Zend\\InputFilter\\BaseInputFilter->validateInputs(Array, Array, NULL)\n
#6 vendor\/zendframework\/zend-form\/src\/Form.php(513): Zend\\InputFilter\\BaseInputFilter->isValid()\n