How to indicate that an entity in a route is optional

[pauljura]

Hi folks,

This section: https://symfony.com/doc/current/doctrine.html#automatically-fetching-objects-entityvalueresolver

The bundle uses the {id} from the route to query for the Product by the id column. If it's not found, a 404 page is generated.

I think this is missing an explanation of how to override the default 404 behaviour.

The solution is to indicate that the method parameter is optional, by inserting a question mark in front of the class name. Some example code might look like this:

class ProductController extends AbstractController
{
    #[Route('/product/{id}')]
    public function show(?Product $product): Response
    {
        if ($product instanceof Product) {
            // use the Product!
            // ...
        } else {
            // your custom response
            // ...
        }
    }
}

I think this was documented at some point, because I know this works and I think I read it here, so I guess at some point this was removed. I think it's a useful feature to know about, so should be documented somewhere.

Thanks