How to insert a detail record with custom id in Panache/JPA?

[rcbgdf]

I have to tables with a one-to-many relation. In the 'many' table I need a custom id (eg. GTIN).
So I have two classes

@Data
@EqualsAndHashCode(callSuper=false)
@Entity(name = "Master")
public class MasterEntity extends PanacheEntity {

    @Getter
    @Setter
    @OneToMany(orphanRemoval = true, cascade = CascadeType.ALL)
    @JoinColumns({
        @JoinColumn(name = "masterId", referencedColumnName = "id")
    })
    private Set<DetailEntity> details = new HashSet<>();
}

@Data
@EqualsAndHashCode(callSuper=false)
@Getter
@Setter
@Entity(name = "Detail")
public class DetailEntity extends PanacheEntityBase {

    @Id
    private Long masterId;

    @Id
    private Long detailId;
}

I wrote a test:

 @Test
    @Transactional
    public void testOneToMany() {
        MasterEntity mediaItemEntity = new MasterEntity();
        DetailEntity mediaItemGtinEntity = new DetailEntity();
        mediaItemGtinEntity.setDetailId(1234567890123L);
        mediaItemEntity.getDetails().add(mediaItemGtinEntity);
        mediaItemEntity.persist();
    }

Caused by: org.postgresql.util.PSQLException: ERROR: null value in column "masterid" of relation "detail" violates not-null constraint
  Detail: Failing row contains (1234567890123, null).

It seems that the generated id for master is not getting propagated to the detail entity. I need to derive detail from EntityBase as I do not need a generated id.

How can I get this working?

[quarkus-bot[bot]]

/cc @FroMage (panache), @loicmathieu (panache)