Expected behavior when traversing deleted relations that are targetAuditMode=RelationTargetAuditMode.NOT_AUDITED

[hltbdivl]

I'm evaluating Envers for historical configuration tracking in our system. So far I really like what I see; our custom history mechanism is many lines of complex code, and Envers has the potential to get rid of that.
One thing I'm stumbling on is Envers' behavior involving deletions and NOT_AUDITED. Here's a sample data model:
{code}
class Foo {
  @Audited(withModifiedFlag=true)
  String interestingField;
  @Audited(targetAuditMode=RelationTargetAuditMode.NOT_AUDITED)
  Bar myBar;
  public boolean equals(Object obj) {
    // compares interestingField and myBar
  }
  public int hashCode() {
    // hashes interestingField and myBar
  }
}
class Bar {
  ...
}
{code}

Now imagine the following:

1. Transaction 1 creates and persists a Foo and a Bar.
2. Transaction 2 deletes both the Foo and the Bar.
3. Transaction 3 queries for all revisions.

What I'm seeing is that the query throws an exception that looks kind of like this:

{quote}
javax.persistence.EntityNotFoundException: Unable to find Bar with id 1
          at org.hibernate.ejb.Ejb3Configuration$Ejb3EntityNotFoundDelegate.handleEntityNotFound(Ejb3Configuration.java:155)
          at org.hibernate.proxy.AbstractLazyInitializer.checkTargetState(AbstractLazyInitializer.java:171)
          at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:160)
          at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:195)
          at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:185)
          ...
          at org.hibernate.envers.tools.Triple.hashCode(Triple.java:74)
          at java.util.HashMap.put(HashMap.java:372)
          at org.hibernate.envers.reader.FirstLevelCache.putOnEntityNameCache(FirstLevelCache.java:87)
          at org.hibernate.envers.entities.EntityInstantiator.createInstanceFromVersionsEntity(EntityInstantiator.java:104)
          at org.hibernate.envers.query.impl.RevisionsOfEntityQuery.list(RevisionsOfEntityQuery.java:134)
          at org.hibernate.envers.query.impl.AbstractAuditQuery.getResultList(AbstractAuditQuery.java:105)
        ...
{quote}

I was expecting to get back two revisions. In the first, I was expecting a Foo associated to null (since the "current" Bar was deleted). At the very least, it'd be nice to avoid initializing Bar's proxy within Envers; let me step on (or avoid) that landmine myself.

[adamw]

The assumption behind RelationTargetAuditMode.NOT_AUDITED relations was that the target entities are kind of "dictionary" ones, that is they are constant through the lifetime of the system. Hence the deletion was never a problem.

Maybe we should add a flag specifying that if the target entity does not exist, it should be null?

Adam

[hltbdivl]

{quote}
Maybe we should add a flag specifying that if the target entity does not exist, it should be null?
{quote}
That would work for me.
Alternatively, if I could delete associated audits when I delete their target entity, that would work too. Or at least nullify the relation to the (now deleted) target entity. I don't think I can delete them today without running a native SQL query. Not to mention that it's not clear what the audit history looks like at that point: I either have revisions with no associated audits, or if I've deleted these "empty" revisions, I've got gaps in my revision list. Neither seem particularly elegant.

[jhuang8285]

hi, everyone

I just encountered the exact problem when I am using Envers to implement our audit feature. I am glad this issue has been reported. It would be nice to have such option in case the assocaited entity has been deleted.

[adamw]

Well, you can't really tamper with history, so no deleting is possible, and I think I'd like to keep it that way.

Can you create a feature request in JIRA?

Adam

[hltbdivl]

Filed https://hibernate.onjira.com/browse/HHH-8051.  I also filed a feature request for history deletion: https://hibernate.onjira.com/browse/HHH-8052.