#914 ✓resolved
John

Patched hibernate 3.6.1 causes save()-related bug

Reported by John | June 15th, 2011 @ 11:58 PM | in 1.2.5 (closed)

Framework version: 1.2.1
Platform you're using: Windows 7 x64, JDK 1.6.0_26 x64

Reproduction steps:
@Entity public class AnEntity extends Model
{ public List children; }

@Entity public class AnotherEntity extends Model
{ public String prop; }

public class Blah
{ public void blah() {

     AnEntity e1 = new AnEntity().save();
     e1.children = new ArrayList<AnotherEntity>();

     //this save will cause collectionEntry for e1.children to be deleted in hibernate for reasons explained below
     new AnotherEntity().save();

    e1.save(); //PersistenceException occured : org.hibernate.HibernateException: Found two representations of same collection

} }

Details:

In patched AbstractFlushingEventListener.java: flushCollections only recreates a CollectionEntry if isDocreate() == true, and if the collection is owned by an entity with willBeSaved==true.

Also in AbstractFlushingEventListener, postFlush() removes all collections for whom getLoadedPersister() == null because it assumes they are dereferenced

When saving AnotherEntity, play does not re-create e1.children because e1 is not the entity being saved. However, if not re-creating e1.children (with CollectionRecreateAction) has the side effect of making getLoadedPersister() == null, which in turn has the side effect of having hibernate remove collection from StatefulPersistenceContext.collectionEntries;

When FlushVisitor.processCollection() runs after second save of AnotherEntity. It calls Collections.processReachableCollection(), which cannot find the children collection in collectionEntries and throws exception:

CollectionEntry ce = session.getPersistenceContext().getCollectionEntry(collection);

    if ( ce == null ) {
        // refer to comment in StatefulPersistenceContext.addCollection()
        throw new HibernateException(
                "Found two representations of same collection: " +
                type.getRole()
        );
    }

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