FetchableFluentQuery ignores 'project'

[trks1970]

spring-data-jpa: 3.0.4

when using JpaSpecificationExecutor.findBy(Specification, FetchableFluentQuery)

and looking at the SQL query generated by hibernate I see that all the entity attributes are queried, not just the ones defined in the project statement of the FetchableFluentQuery.

Executing:

Set<IdProjection> children =
        new HashSet<>(
            jpaChildEntityRepository.findBy(
                ChildEntitySpecification.parent(id),
                fetchableFluentQuery ->
                    fetchableFluentQuery.as(IdProjection.class).project(ChildEntity_.ID).all()));

generates the SQL:

select c1_0.id,c1_0.description,c1_0.name,c1_0.parent_id,c1_0.revision from child c1_0 where c1_0.parent_id=?

complete code is available at: GitHub
ParentServiceTest.deleteWithChildren

[schauder]

Duplicate of #2721