final Serializable id = persister.hasIdentifierProperty() ?
persister.getIdentifier( entity, source.getEntityMode() ) :
null;
final Object copy = persister.instantiate( id, source.getEntityMode() ); //TODO: should this be Session.instantiate(Persister, ...)?
copyCache.put(entity, copy); //before cascade!
// cascade first, so that all unsaved objects get their
// copy created before we actually copy
//cascadeOnMerge(event, persister, entity, copyCache, Cascades.CASCADE_BEFORE_MERGE);