Symfony3 and PHP 7 return type decleration for Doctrine Repository methods - doctrine-orm

Question

I really like PHP's return type declarations, and I want to use it on Symfony 3.
All controller methods should return a Response object, no problem there. But in Doctrine repositories though, Doctrine might return an Entity object, or null.
Consider this example:
You have created a simple Post entity.
You have created a custom findByName method in PostRepository:
PostRepository.php
public function findByName($name) : Post
{
$qb = $this->createQueryBuilder('p')
->where('p.name = :name')
->setParameter('name', $name);
$post = $qb->getQuery()->getOneOrNullResult();
return (null === $post) ? new Post() : $post;
}
You call this method from a controller, like this:
DefaultController.php
/**
* #Route("/", name="homepage")
*/
public function indexAction(Request $request)
{
$em = $this->getDoctrine()->getManager();
$repository = $em->getRepository('AppBundle:Post');
try {
$post = $repository->findByName('test');
} catch (\TypeError $e) {
$post = new Post();
}
return new Response(dump($post));
}
I am aware trying to catch exception won't execute because findByName() always returns a Post object.
My question is, where should we handle the exception? According to this answer, it is better to throw an exception. Should we ensure repository method does not throw an exception at all by using this:
$post = $qb->getQuery()->getOneOrNullResult();
return (null === $post) ? new Post() : $post;
or let PHP throw a TypeError exception and let controller handle it?
Doctrine, throws exceptions for getOneOrNullResult() and getSingleResult() methods as described here.
If this scenario doesn't make sense because it's better to let your controller handle the exception and return a "not found" page because post doesn't exist like this:
return $this->createNotFoundException();
Scenario #2
Post exists in the database, and another repository method is called, getApprovedComments(), no comments are returned, we're expecting an ArrayCollection but we get an array. This will throw PHP's TypeError exception.
I think code is going to be full of try/catch blocks. Is it ok to handle this kind of exceptions at a higher level to have less try/catch blocks in code?
At a second thought this is not the best solution, because code should be flexible enough to catch every TypeError exception and take proper action on how to render the page.