| Note: Bug first noticed in our code on Hibernate 5.0.10.Final.
Created a testcase on 5.2.2.Final with the exact same behavior. Testcase attached. If
- you have a previously-persisted parent entity A with a ManyToOne list property B of not-yet-persisted entities C
- and there is no cascade-setting on B (defaults to empty list) *
- and you perform a merge on A (`entityManager.merge(A);`)
you'll end up with A containing for it's property B a collection of "empty copies" of C, call them C', which are newly-constructed objects without the attribute values C had.
Obviously, this leads to problems and is an unwanted situation. This seems to come from the `null` value on CollectionType#549
```while ( iter.hasNext() ) { result.add( elemType.replace( iter.next(), null, session, owner, copyCache ) ); } ``` combined with EntityType#352-357
```if ( session.getContextEntityIdentifier( original ) == null &&
ForeignKeys.isTransient( associatedEntityName, original, Boolean.FALSE, session ) ) { final Object copy = session.getEntityPersister( associatedEntityName, original ) .instantiate( null, session ); copyCache.put( original, copy ); return copy; } ``` which says that if original (child object C) is unsaved then a new instantion of C should be created and returned. |