Missing validations for date range type

[johnkrovitch]

When using the date range form type, if we fill only the start date and leave the endDate empty, an exception is thrown.

A validator should be applied to return a form error and the bundle should not throw exception for a missing field.

[johnkrovitch]

The error is present event if the two fields are filled :

"Cannot read index "startDate" while trying to traverse path "[startDate]". Available indices are "Array
(
)
".

[johnkrovitch]

It is missing a transform like :

 ->addModelTransformer(new CallbackTransformer(function ($value) {
                if (null === $value) {
                    $value = [
                        'startDate' => null,
                        'endDate' => null,
                    ];
                }
                
                return $value;
            }, function ($value) {
                
                return $value;
            }))