[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-2763) (lazy) m:n relation + EventListener = AssertionFailure: collection [n-side] was not processed by flush()

[Michael Newcomb (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-2763?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_29892 ] 

Michael Newcomb commented on HHH-2763:
--------------------------------------

The problem is that AbstractFlushingEventListener.performExecutions() can result in new CollectionEntrys being created (because listeners access lazy collections, etc...). These CollectionEntry objects are technically created during a flush but not when the PersistenceConext.flushing attribute is set.

I looks safe to update AbstractFlushingEventListener.performExecutions() to:

session.getPersistenceContext().setFlushing(true);
try {
  session.getJDBCContext().getConnectionManager().flushBeginning();
  // we need to lock the collection caches before
  // executing entity inserts/updates in order to
  // account for bidi associations
  session.getActionQueue().prepareActions();
  session.getActionQueue().executeActions();
}
catch (HibernateException he) {
  log.error("Could not synchronize database state with session", he);
  throw he;
}
finally {
  session.getPersistenceContext().setFlushing(false);
  session.getJDBCContext().getConnectionManager().flushEnding();
}

That should get rid of this issue, but I am have not analyzed everything that occurs in session.getActionQueue().executeActions() so there could be some side affect, but since the 'flushing' attribute is really only used for CollectionEntry objects, it seems safe.


> (lazy) m:n relation + EventListener = AssertionFailure: collection [n-side] was not processed by flush()
> --------------------------------------------------------------------------------------------------------
>
>                 Key: HHH-2763
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2763
>             Project: Hibernate3
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 3.2.4.sp1, 3.2.5
>         Environment: Windows-XP, Jboss 4.2.1GA, Hibernate 3.2.4SP1, EJB3
>            Reporter: S.Schnabl
>            Priority: Critical
>         Attachments: bidirectional_many-to-many.gif, cdel_analyse.txt, HHH-2763_standalone_testcases.zip, one-to-many_with_many_side_having_collections.gif, Testcase.zip
>
>
> For more details see the attached testcase. I'm sorry, but in the short of time i only got a testcase for jboss-server 4.2. Please deploy the server.ear from /release-directory and then call the /src/client/TestCaseClient.java.
> [Summarized]
> It seems, that touching a lazy (Persistent-)Collection of at least a m:n relation inside a Hibernate event-listener always raises this error:
> org.hibernate.AssertionFailure: collection [n-side] was not processed by flush()
> [Explanation]
> I have two entities A. and B. Both having a m:n relation between each other. Furthermore there is an PostUpdateListener, which iterates onUpdate of entitiy through all properties of updated entity.
> [Testcase]
> Both entities are linked with eachother (m:n). If i  now do a simple update of a property of entity A --> MyPostUpdateListener will be called, which iterates through every property of the updated entity. In case of this property was a collection (= lazy PersistentCollection of m:n relation), hibernate initializes the collection for further work. I can now run through all objects of the collection, but after all work is done in listener, I get the following exception from postFlush:
> Caused by: org.hibernate.AssertionFailure: collection [com.qualitype.testcase.server.ejb.entity.EntityB.entitiesOfA] was not processed by flush()
> at org.hibernate.engine.CollectionEntry.postFlush(CollectionEntry.java:205)
> at org.hibernate.event.def.AbstractFlushingEventListener.postFlush(AbstractFlushingEventListener.java:333)
> at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:28)
> at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000)
> at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338)
> at org.hibernate.ejb.AbstractEntityManagerImpl$1.beforeCompletion(AbstractEntityManagerImpl.java:515)
> ... 29 more
> Attention: EntityB.entitiesOfA is the other-side  collection of the m:n relation of the updated EntityA.
> We are using hibernate-event listener system for auditing-purposes, so you should understand that touching every (element in the) collection is necessary for audit-purposes.
> Seems for me like a serious bug. Need this fixed asap ...

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