Add @RequestScoped EntityManager Example #238

A very common pattern is to use an EntityManager which is @RequestScoped with CDI. This is often referred to as the entitymanager-per-request pattern.

Currently I am unable to make this work in coordination with @Transactional without going SynchronizationType.UNSYNCHRONIZED and manually calling an entityManager.joinTransaction()

public class PersistenceResources {

    @PersistenceContext(type = PersistenceContextType.EXTENDED, synchronization = SynchronizationType.SYNCHRONIZED)
    private EntityManager em;

    @Produces
    @RequestScoped
    private EntityManager requestScopedEntityManager() {
        return em;
    }
}

Unfortunately all the entities appear to get detached after the first transaction commits. Is this pattern possible with EE 7 without having to manually join to the transaction?