However NoResultException is thrown only when hydration mode is not HYDRATE_SINGLE_SCALAR.

That's not quite correct as $result = $this->execute(null, $hydrationMode); can still throw NoResultException exception.

Please see screenshot:

How to reproduce:

$qb = $this->em->createQueryBuilder();

$qb->select('p.code')
   ->from('App:Product', 'p')
   ->where('p.name = :name')
   ->setMaxResults(1)
   ->setParameter('name', 'missing');

$code = $qb->getQuery()->getSingleScalarResult();

You're right. Please send a PR to add back the @throws annotation.

Shall I add back only @throws annotation or revert this PR completely?

I can't make getSingleScalarResult return null under any condition, I think the original code was correct.

I'd suggest to revert this PR altogether unless @whatUwant can provide a test case for returning null.

It's correct that NoResultException can still be thrown.
null can be returned when aggregate functions such as MIN MAX are used.

$qb = $this->em->createQueryBuilder();

$qb->select('MAX(p.id)')
   ->from('App:Product', 'p')
   ->where('p.name = :name')
   ->setParameter('name', 'missing');

$code = $qb->getQuery()->getSingleScalarResult();

getSingleScalarResult() with a SELECT on a nullable field should yield null, shouldn't it?

getSingleScalarResult() with a SELECT on a nullable field should yield null, shouldn't it?

You are totally right 👍