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

[Alexander Wels]

On Monday, June 01, 2015 04:09:08 PM Michal Skrivanek wrote:
> On Jun 1, 2015, at 15:59 , Tomas Jelinek <tjelinek at redhat.com> wrote:
> > ----- Original Message -----
> > 
> >> From: "Liran Zelkha" <lzelkha at redhat.com>
> >> To: "Tomas Jelinek" <tjelinek at redhat.com>
> >> Cc: awels at redhat.com, devel at 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?
> > 
> > because the PersistenBag has an inner property "bag" and FE fails on bunch
> > of NPEs because of it> 
> >> Where do you get these errors?
> > 
> > open debug mode and load webadmin - you will see loads of NPEs
> 
> does this happen in normal mode too?
> 

It does not appear to happen in Chrome, but I have some open bugzillas about 
unexplained null pointer exceptions in IE (the null pointers are during 
transfer of objects), which may or may not be related to this problem. 
Regardless doing any work in the GWT debugger is impossible right now due to 
these exceptions.

> >>> On Jun 1, 2015, at 4:33 PM, Tomas Jelinek <tjelinek at redhat.com> wrote:
> >>> 
> >>> 
> >>> 
> >>> ----- Original Message -----
> >>> 
> >>>> From: "Alexander Wels" <awels at redhat.com>
> >>>> To: devel at ovirt.org
> >>>> Cc: "Tomas Jelinek" <tjelinek at redhat.com>, "Liran Zelkha"
> >>>> <lzelkha at redhat.com>
> >>>> 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 at ovirt.org
> >>>>> http://lists.ovirt.org/mailman/listinfo/devel
> > 
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