Hibernate: merge detached entities with inheritance ignore null attributes on child classes

[antoinechamot]

Describe the bug

Using Hibernate entity inheritance ( Quarkus 3 ).

I have created a repository with a test class to reproduce the bug: https://github.com/antoinechamot/quarkus-bugfind. Launch tests (one must fail )

My entities are

@SuperBuilder
@NoArgsConstructor
@Setter
@Getter
@Inheritance(strategy = InheritanceType.JOINED)
@Entity(name = "shape")
public abstract class Shape {

    @Id
    @Builder.Default
    private UUID id = UUID.randomUUID();

    @Column(nullable = false, length = 100)
    private String name;

    @Column(length = 100)
    private String surname;
}

@Entity(name = "circle")
@SuperBuilder
@NoArgsConstructor
@Getter
@Setter
public class Circle extends Shape{

    private String color;
}

I have a simple repository with one method

@Override
@Transactional
public Circle update(Circle circle) {
    return getEntityManager().merge(circle);
}

For test i populate the database with some data:

INSERT INTO shape (id,name,surname) VALUES ('847dae35-7ae0-4041-8257-e23fb7c5b033','My circle','My surname');
INSERT INTO circle (id,color) VALUES ('847dae35-7ae0-4041-8257-e23fb7c5b033','red');
...

And then i run a test to update the circle color to null

    /**
     * Update Circle color to null : KO
     */
    @Test
    void testUpdateCircleColorNullKO(){
        Circle myCircle = Circle.builder()
                .id(UUID.fromString("847dae35-7ae0-4041-8257-e23fb7c5b033"))
                .name("My circle")
                .surname("My surname")
                .color(null)
                .build();

        repository.update(myCircle);

        Circle updatedCircle = repository.findById(UUID.fromString("847dae35-7ae0-4041-8257-e23fb7c5b033"));
        assertThat(updatedCircle.getColor()).isNull();
    }

Expected behavior

• On merge, I expect hibernate to launch an update request to set the value in the color column of the circle table to null.
• If I put null on surname for example, an update request is launched by hibernate.
• It seems that the problem only occurs on attributes of the child class Circle and not on the parent class Shape

Actual behavior

• On merge, null attributes of the child class Circle are ignored. Not update request is done on the circle table.
• If I update the color to something not null like 'blue', it is correctly updated

How to Reproduce?

Repository : https://github.com/antoinechamot/quarkus-bugfind

Output of uname -a or ver

No response

Output of java -version

No response

Quarkus version or git rev

No response

Build tool (ie. output of mvnw --version or gradlew --version)

No response

Additional information

No response

[quarkus-bot]

/cc @gsmet (hibernate-orm), @yrodiere (hibernate-orm)

[yrodiere]

Hello,

Is this different from #38722 ? Because that one is a bug in Hibernate ORM, not in Quarkus, and it's already being fixed upstream.

If it's not the same bug, you might want to check these already-reported issues that mention "merge": https://github.com/quarkusio/quarkus/issues?q=is%3Aissue+is%3Aopen+merge+label%3Aarea%2Fhibernate-orm

[antoinechamot]

Hi,
It could be indeed related to #38722 as inheritance can be considered as "some case". No sure tho as I am not a specialist of hibernate ORM
Are you referring to this hibernate PR in progress on bytecode enhancement : hibernate/hibernate-orm#7912 ?

[yrodiere]

I am referring to https://hibernate.atlassian.net/browse/HHH-17761 and the corresponding PR hibernate/hibernate-orm#7912 , yes.

[yrodiere]

@antoinechamot I'll go ahead and close this as duplicate of #38722, which has been fixed on main (Quarkus 3.11). Feel free to comment here if it turns out this was a different problem.
Thanks for your feedback.