io.objectbox.exception.DbDetachedException when iterat a empty ToMany<>

[crazyxu]

1.2.1 kotlin
i have a ToMany<> whoes content may be empty, i need add if (xxx.addCount == 0) return to avoid crash.

[greenrobot-team]

Does your entity have @Id(assignable = true) and did you create the entity with the ToMany yourself (you did not get it from its box)?

If yes, either put the entity first or call box.attach(entity) to attach it to its box. (See notes on Updating ToMany.)

If the above is not the case, it would be helpful if you share a little example project so we can reproduce this.
-ut

[greenrobot]

No response, issue is not clear to me.

[williamwue]

Thanks very much. I have meet same issue, and "box.attach(entity)" works for me