Re: [ovirt-devel] hibernate's internal PersistentBag sent to FE

From: "Liran Zelkha" <lzelkha(a)redhat.com&gt; To: "Tomas Jelinek" <tjelinek(a)redhat.com&gt; Cc: awels(a)redhat.com, devel(a)ovirt.org Sent: Monday, June 1, 2015 3:56:03 PM Subject: Re: [ovirt-devel] hibernate's internal PersistentBag sent to FE Guys, Why is https://gerrit.ovirt.org/#/c/40804/ not enough?

Where do you get these errors?

> On Jun 1, 2015, at 4:33 PM, Tomas Jelinek <tjelinek(a)redhat.com&gt; wrote: > > > > ----- Original Message ----- >> From: "Alexander Wels" <awels(a)redhat.com&gt; >> To: devel(a)ovirt.org >> Cc: "Tomas Jelinek" <tjelinek(a)redhat.com&gt;, "Liran Zelkha" >> <lzelkha(a)redhat.com&gt; >> Sent: Monday, June 1, 2015 3:16:34 PM >> Subject: Re: [ovirt-devel] hibernate's internal PersistentBag sent to FE >> >>> On Monday, June 01, 2015 09:08:50 AM Tomas Jelinek wrote: >>> Hey all, >>> >>> since the org.ovirt.engine.core.common.job.Job/Step... has been moved to >>> use >>> the JPA we have a problem on frontend. The problem is that the @OneToMany >>> annotations results in a List which is of type PersistentBag. When we >>> send >>> this to Frontend it fails during deserialization. It actually fails quite >>> bad because the FE already has an ui-override of it which is not correct >>> resulting in a ton of NPEs in development mode. >>> >>> So, there are 2 nasty fixes I have made where none of them should be >>> merged >>> but demonstrate the possibilities: 1: extend the FE to be able to work >>> with >>> the PersistentBag (https://gerrit.ovirt.org/#/c/41682/) not really good >>> solution since the PersistenBag is an internal Hibernate class which is >>> really not meant to be passed around >>> >>> 2: fix on the backend to not send the PersistentBag but an ArrayList. >>> This >>> is only a PoC fixed on a command we face the problem >>> (https://gerrit.ovirt.org/#/c/41797/) Obviously this is not going to work >>> for other commands accessing the same Job nor for other entities. >>> >>> So, the first option is generic but very very bad. The second option >>> should >>> be used but not sure how to do this in a cheep way (e.g. without using >>> reflection to deep traverse everything sent back to frontend checking if >>> it >>> does not have a PersistentBag in it. >> >> Tomas, >> >> Thanks, I was investigating the same issue, I noticed it last Friday just >> before leaving, so I was investigating the problem to see what was going >> on. >> You are right we should not be sending PersistentBag to the frontend at >> all. >> So how about we do a combination of [1] and [2], but instead of delegating >> in >> [1] we actually simple throw an exception stating don't sent PersistentBag >> to >> the front end. that way anyone inadvertently using it will be notified >> immediately (since their code won't work). > > Throwing the exception would help us in debugging but the main question is > how will we make it work? > Since we are planning to move more and more to JPA so we will face this > issue more and more often. > Solving it one by one on backend in each command is not going to work. > >> >> Alexander >> >>> Any better ideas? >>> Thanx, >>> Tomas >>> _______________________________________________ >>> Devel mailing list >>> Devel(a)ovirt.org >>> http://lists.ovirt.org/mailman/listinfo/devel >> >>