[hibernate-issues] [Hibernate-JIRA] Closed: (HHH-4135) Merging of one-to-many relations not JPA spec compliant for lazy relations

[Steve Ebersole (JIRA)]

     [ http://opensource.atlassian.com/projects/hibernate/browse/HHH-4135?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Steve Ebersole closed HHH-4135.
-------------------------------

    Resolution: Rejected

Correct the spec does say that
{quote}
The persistence provider must not merge fields marked LAZY that have not been fetched: it must ignore
such fields when merging.
{quote}

It really comes down to the definition of "merge".  And what does it mean to ignore "such a field when merging"?

Well it also says that
{quote}
The merge operation allows for the propagation of state from detached entities onto persistent entities
managed by the entity manager.
{quote}

The important piece is the "propagation of state".

> Merging of one-to-many relations not JPA spec compliant for lazy relations
> --------------------------------------------------------------------------
>
>                 Key: HHH-4135
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-4135
>             Project: Hibernate Core
>          Issue Type: Bug
>          Components: entity-manager
>         Environment: Hibernate 3.2.6, Hibernate EntityManager 3.4.0, Hibernate Annotations 3.4.0, Oracle  
>            Reporter: Dirk
>         Attachments: CascadeTest.zip
>
>
> Topic has been posted to the Hibernate Forum. See https://forum.hibernate.org/viewtopic.php?f=1&t=999398
> Summary:
> Suppose you have an object Master with one-to-many relation to Detail. 
> @Entity
> public class Master implements Serializable {
>     @OneToMany(mappedBy = "master", cascade={CascadeType.MERGE, CascadeType.PERSIST})
>     private List<Detail> details = new ArrayList<Detail>();
> ...
> }
> Master is loaded without fetching Detail (= lazy) and EntityManager is closed. Master is now in detached state. Merging Master causes Hibernate EntityManager to eagerly load the Detail collection although it is in lazy state. This is not JPA spec compliant.
> JPA spec states: The persistence provider must not merge fields marked LAZY that have not been fetched: it must ignore
> such fields when merging. See 3.2.4.1 Merging Detached Entity State, p.51.
> Tested also with the latest version of EclipseLink. EclipseLink behaves as expected.
> Testcase attached (Netbeans 6.7).

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