[Flow] Validator is not called ...

[Tomas M]

Hello!

I have defined two classes; both are presisted in db (see code snipped below).

In the according form the user selects one "car" from a select box.
As long the user really selects one, all is fine.

But if the field is left blank I get

Exception while property mapping for target type "My\Pkg\Domain\Model\myObject", at property path "":
Catchable Fatal Error: Argument 1 passed to My\Pkg\Domain\Model\myObject_Original::setCar() must be an instance of 
My\Pkg\Domain\Model\Car, null given ....


First I've used 

  @Flow\Validate(type="NotEmpty")

but I got exactly the same message. 

My validator is called only, if a "car" was selected
else I get the message above.


What I'm doing wrong?

Does someone have an idea?






/**
 * @Flow\Entity
 */
class myObject {

	/**
	* @var string
	*
	* @Flow\Validate(type="Text")
	* @Flow\Validate(type="StringLength", options={ "minimum"=5, "maximum"=80 })
	* ORM\Column(length=255)
	*/
	
	protected $theLabel;
	

	/**
	 * @var \My\Pkg\Domain\Model\Car
	 * @Flow\Validate( argumentName="car", type="\My\Pkg\Validation\Validator\myObjectValidator",  options={})
 	 * @ORM\ManyToOne
	 */

	protected $car;

	
	...
	

}