Fix: Check PropertyPath value for add error to form

[lchrusciel]

Q	A
Branch?	1.6
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no
Related tickets	replaces #10689
License	MIT

[Coosos]

@lchrusciel
Last commit who remove is_null check is not included : b4edb10

EDIT : I let you do to avoid making a bad manipulation

[Zales0123]

Is there any possibility to add some test to that fix?

[lchrusciel]

When I tried to code one, I've found one scenario added already: https://github.com/Sylius/Sylius/blob/master/features/inventory/cart_inventory/prevent_buying_more_products_than_available_in_a_stock.feature#L26-L30

Also, tested manually and it works at the current master:

@Coosos can you check it as well?

[Coosos]

@lchrusciel

I've checked with demo version (1.5 and master) and I reproduced.
Example to reproduce (fresh installation) :

In \Sylius\Bundle\InventoryBundle\Validator\Constraints\InStockValidator, line 45, add (just after assert) :

$this->context->addViolation(
   $constraint->message,
   ['%itemName%' => 'Example item']
);

And with the browser, test to add a product, no error is displayed

With the fix, the error is displayed 👍