text_array type propery that is nullable

[ChrisChrisi]

When I use the text_array type and want to set the value of the proprty to null the convertToDatabaseValue() method of TextArrayType class automatically set it to ematy array ( {}). I don't want the field value to be emty array. I want it to be null. I want the values of the property to can be set to null or text array.