Error HR000069 when with simeoultaneous requests to @ReactiveTransactional REST endpoint

[phinjensen]

I've got an application that, for legacy compatibility, manages its own data_lock table for one of the models, Person. I have a route that looks up a person and adds a lock to the data_lock table, then looks up and returns a child model. The resource looks like this:

@Path("/secure/person/{personId}/child")
@Consumes("application/json")
@Produces("application/json")
public class PersonChildResource {
  @GET
  @Path("/{id}")
  @ReactiveTransactional
  public Uni<PersonChild> getChild(@Context SecurityContext sec, @RestPath long personId, @RestPath long id) {
    return Person.lock(sec.getUserPrincipal().getName(), personId)
        .onFailure(PersistenceException.class)
        .retry()
        // .withBackOff(Duration.ofMillis(100))
        .atMost(3)
        .chain(
            person ->
                PersonChild.find("person_id = ?1 AND id = ?2", personId, id).firstResult());
  }
}

The Person.lock function is what looks up the Person and adds a row to data_lock. Basically, it finds a person and user, checks to see if the person is locked (i.e. has a row referencing it in the data_lock table where the user is not the authenticated user), and if it's unlocked creates and persists a new lock before returning the user:

@Table(schema = "public", name = "person")
@Entity
public class Person extends PanacheEntity {
  // ...

  @OneToMany(
      mappedBy = "person",
      fetch = FetchType.EAGER)
  private List<Lock> locks;

  public static Uni<Person> lock(String uid, Long id) {
    LOG.info("Locking person " + id + " by user " + uid);
    return Uni.combine()
        .all()
        .unis(
            Person.<Person>findById(id)
                .map(
                    person -> {
                      person.locked =
                          person.locks.stream().anyMatch(lock -> !lock.user.uid.equals(uid));
                      return person;
                    }),
            User.findByUid(uid))
        .asTuple()
        .call(
            tuple -> {
              Person person = tuple.getItem1();
              if (!person.locked) {
                Lock lock = new Lock();
                lock.person = person;
                lock.user = tuple.getItem2();
                return lock.persist();
              }
              return Uni.createFrom().voidItem();
            })
        .map(tuple -> tuple.getItem1());
  }
}

And the Lock class for data_lock:

@Table(schema = "public", name = "data_lock")
@Entity
public class Lock extends PanacheEntityBase {
  @Id
  @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "data_lock_id")
  public Long id;

  @ManyToOne
  @JoinColumn(name = "user_id")
  public User user;

  @ManyToOne(fetch = FetchType.LAZY)
  @JoinColumn(name = "person_id", nullable = true)
  @JsonIgnore
  public Person person;

  @Column(name = "lock_time")
  @CreationTimestamp
  public LocalDateTime lockTime;

  // Private so as to not loop when fetching a Person
  @ManyToOne(fetch = FetchType.LAZY)
  @JoinColumn(name = "person_child_id", nullable = true)
  private PersonChild personChild;
}

I'm using @ReactiveTransactional and sticking to PanacheEntity classes. However, I have a frontend page that fetches the /secure/person/{personId}/child/{id} twice simeoultaneously, and the first time I do that after restarting the server, one of the requests always fails with the following error:

2022-08-05 10:25:56,828 ERROR [org.jbo.res.rea.com.cor.AbstractResteasyReactiveContext] (vert.x-eventloop-thread-0) Request failed: java.lang.IllegalStateException: HR000069: Detected use of the reactive Session from a different Thread than the one which was used to open the reactive Session - this suggests an invalid integration; original thread [119]: 'vert.x-eventloop-thread-0' current Thread [120]: 'vert.x-eventloop-thread-1'
...

I can post the full stack trace if it helps, but it's all library calls, not anything from my app. The weird thing is that after throwing this error the first time, any more simultaneous requests work perfectly. Trying to add a delay to the retry (the commented line in PersonChildResource) doesn't help.

I've seen other threads and questions about this error, but most of them say either to double-check that you're using Panache for everything (I am) or that it's a bug that has since been fixed. I'm not super familiar with reactive programming, Java, or any of these libraries, so I imagine I'm just doing something wrong. If anyone could help me in the right direction, I would greatly appreciate it.