Tengo el problema de que SpEL está evaluando el argumento de la entidad como referencia nula en el segundo método de este repositorio. Este primer método funciona bien y la identificación se evalúa correctamente en Long como debería ser.

@NoRepositoryBean
public interface SecuredPagingAndSortingRepository<T extends AuditedEntity, ID extends Serializable>
        extends PagingAndSortingRepository<T, ID> {

    @Override
    @RestResource(exported = false)
    @PreAuthorize("hasPermission(#id, null, 'owner')")
    void delete(ID id);

    @Override
    @PreAuthorize("hasPermission(#entity, 'owner')")
    void delete(T entity);
}

Este es mi PermissionEvaluator personalizado:

@Slf4j
@Component
public class CustomPermissionEvaluator implements PermissionEvaluator {

    private final PermissionResolverFactory permissionResolverFactory;

    @Autowired
    public CustomPermissionEvaluator(PermissionResolverFactory permissionResolverFactory) {
        this.permissionResolverFactory = permissionResolverFactory;
    }

    @Override
    public boolean hasPermission(Authentication authentication, Object targetDomainObject, Object permission) {
        UserDetails userDetails = (UserDetails) authentication.getPrincipal();
        Assert.notNull(userDetails, "User details cannot be null");
        Assert.notNull(targetDomainObject, "Target object cannot be null");
        log.debug("Permmission: " + permission + " check on: " + targetDomainObject + " for user: " + userDetails.getUsername());

        PermissionType permissionType = PermissionType.valueOf(((String) permission).toUpperCase());
        return permissionResolverFactory.getPermissionResolver(permissionType).resolve(targetDomainObject.getClass(), authentication, (AuditedEntity) targetDomainObject);
    }

    @Override
    public boolean hasPermission(Authentication authentication, Serializable targetId, String targetType, Object permission) {
        // TODO
        return false;
    }
}

Esta prueba no pasa porque se afirma que el objeto de destino no puede ser nulo en CustomPermissionEvaluator.

@RunWith(SpringRunner.class)
@SpringBootTest
@Transactional
@ContextConfiguration(classes = SqapApiApplication.class)
public class PermissionsIT {
    @Autowired
    private TestGroupRepository testGroupRepository;

    @Autowired
    private UserRepository userRepository;

    UserEntity user;

    @Before
    public void before() {
        user = new UserEntity("user", "password1", true, Sets.newHashSet(RoleType.ROLE_USER));
        user = userRepository.save(user);
    }

    @Test
    @WithMockUser(username="user")
    public void shouldDeleteWhenIsOwner() throws Exception {
        TestGroupEntity testGroupEntity = new TestGroupEntity("testGroup", "testdesc", Sets.newHashSet(new AbxTestEntity(1, "abx", "desc", null)));
        user.addTestGroup(testGroupEntity);
        user = userRepository.save(user);
        TestGroupEntity createdEntity = testGroupRepository.findAll().iterator().next();
        testGroupRepository.delete(createdEntity);
    }
}