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

[Michal Skrivanek]

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?

> 
>> 
>> 
>> 
>>> 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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