[Engine-devel] java 1.6 compatibility no more?

[Itamar Heim]

On 07/23/2012 08:29 AM, Allon Mureinik wrote:
>
>
> ----- Original Message -----
>> From: "Itamar Heim" <iheim at redhat.com>
>> To: "Allon Mureinik" <amureini at redhat.com>
>> Cc: "Livnat Peer" <lpeer at redhat.com>, "Juan Hernandez" <jhernand at redhat.com>, engine-devel at ovirt.org, "Michael
>> Kublin" <mkublin at redhat.com>
>> Sent: Sunday, July 22, 2012 7:41:00 PM
>> Subject: Re: [Engine-devel] java 1.6 compatibility no more?
>>
>> On 07/22/2012 07:38 PM, Allon Mureinik wrote:
>>>
>>>
>>> ----- Original Message -----
>>>> From: "Livnat Peer" <lpeer at redhat.com>
>>>> To: "Itamar Heim" <iheim at redhat.com>, "Michael Kublin"
>>>> <mkublin at redhat.com>
>>>> Cc: "Juan Hernandez" <jhernand at redhat.com>, engine-devel at ovirt.org
>>>> Sent: Sunday, July 22, 2012 9:50:47 AM
>>>> Subject: Re: [Engine-devel] java 1.6 compatibility no more?
>>>>
>>>> On 21/07/12 15:15, Itamar Heim wrote:
>>>>> On 07/19/2012 03:34 PM, Ayal Baron wrote:
>>>>>>
>>>>>>
>>>>>> ----- Original Message -----
>>>>>>>
>>>>>>> On Jul 19, 2012, at 14:14 , Livnat Peer wrote:
>>>>>>>
>>>>>>>> On 19/07/12 14:41, Juan Hernandez wrote:
>>>>>>>>> On 07/19/2012 01:39 PM, Yair Zaslavsky wrote:
>>>>>>>>>> On 07/19/2012 02:31 PM, Vojtech Szocs wrote:
>>>>>>>>>>>> Don't we need that (the source part) to avoid Java 7
>>>>>>>>>>>> syntax
>>>>>>>>>>>> in
>>>>>>>>>>>> GWT code?
>>>>>>>>>>>
>>>>>>>>>>> That's a very good point.
>>>>>>>>>>>
>>>>>>>>>>> In general, GWT compiler supports Java 5 syntax (note that
>>>>>>>>>>> there
>>>>>>>>>>> are no language changes between Java 5 and 6). For this
>>>>>>>>>>> reason,
>>>>>>>>>>> our frontend code should be compliant with Java 5. If
>>>>>>>>>>> someone
>>>>>>>>>>> uses new Java 7 language features in frontend code, GWT
>>>>>>>>>>> compiler will throw an error and the build will fail.
>>>>>>>>>>>
>>>>>>>>>>> So the 'Java 5 only' limitation applies to frontend code
>>>>>>>>>>> and
>>>>>>>>>>> any
>>>>>>>>>>> other code (e.g. shared modules) that is directly
>>>>>>>>>>> referenced
>>>>>>>>>>> by
>>>>>>>>>>> frontend code. This shouldn't affect the backend, however.
>>>>>>>>>>>
>>>>>>>>>>> We could do something like this:
>>>>>>>>>>>
>>>>>>>>>>> - let oVirt root POM declare source and target compliance
>>>>>>>>>>> to
>>>>>>>>>>> Java 7
>>>>>>>>>>> - let frontend modules POM
>>>>>>>>>>> (frontend/webadmin/modules/pom.xml)
>>>>>>>>>>> declare source compliance to Java 5 (or 6)
>>>>>>>>>>>
>>>>>>>>>>> (note that target compliance can be left to Java 7 since
>>>>>>>>>>> frontend compilation results in JavaScript code)
>>>>>>>>>>>
>>>>>>>>>>> What do you think?
>>>>>>>>>>>
>>>>>>>>>>> Vojtech
>>>>>>>>>>
>>>>>>>>>> +1 - I really like this idea!
>>>>>>>>>
>>>>>>>>> +1 from me as well.
>>>>>>>>
>>>>>>>>
>>>>>>>> There are two calls to make when it comes to JDK7 (regardless
>>>>>>>> of
>>>>>>>> GWT -
>>>>>>>> excuse me for taking this discussion some steps backwards)
>>>>>>>>
>>>>>>>> 1. Are we running with JRE 7?
>>>>>>>> The answer is yes we agreed on that a few months ago.
>>>>>>>>
>>>>>>>> 2. Are we using code syntax which is incompatible with JDK6?
>>>>>>>>
>>>>>>>> I think the answer to the above should be no (at least for now
>>>>>>>> -
>>>>>>>> maybe
>>>>>>>> until the next ovirt release?).
>>>>>>> +1
>>>>>>> exactly. Why starting with jdk6 incompatible constructs unless
>>>>>>> there
>>>>>>> is a good (or at least any) reason for them…
>>>>>>
>>>>>> +1
>>>>>
>>>>> +1 - there is merit keeping backward compatibility to allow
>>>>> comparing
>>>>> behavior while java 7 is still young.
>>>>
>>>> Since no one objected, we'll go with JDK6 syntax compatibility for
>>>> Now.
>>> I'm a very small fan of enforcing policy by reviewers.
>>> Not that the community reviews aren't great - but people miss
>>> things.
>>>
>>> Here's my take on Maven's enforcer plugin to actually verify we
>>> aren't compiling with JDK 7:
>>> http://gerrit.ovirt.org/#/c/6523
>>
>> we don't want to enforce compilation or run with JDK 6, only to
>> preserve
>> backward compatibility.
>> I'm for jenkins to have a job to compile and run unitests with
>> openjdk 6
>> to be on the safe side.
>
> I don't understand this suggestion.
> What you're saying is that you can compile with whatever JDK you want, but:
> - it won't compile with JDKs prior to 6, since we're using 6's features.
> - you aren't allowed to use JDK 7 features, and if you do, you'll get an email from jenkins that you broke something and must fix it.
>
> To me, this sounds a lot like enforcing JDK 6 compatibility.
>

its preserving jdk 6 compatibility for a few more months, not enforcing 
to use jdk 6 compiler.

> /today/ if have way too many (i.e., >0) jenkins breaks, a lot of which could be avoided by not running with -DskipTetst or making sure to run with -Penable-dao-tests.
> I fear this suggestion will just add to this "noise", and could easily be avoided.

jenkins breaks should be visible at patch level prior to commit, 
something we are trying to resolve by adding more hardware to allow 
running the various tests at patch level rather than post commit only.

>
>>
>>>
>>> comments welcome.
>>>
>>>>
>>>> Kublin - can you please send a patch to remove the usage of
>>>> Long.Compare
>>>> in StorageDomainCommandBase
>>>>
>>>> Thanks, Livnat
>>>>
>>>>
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>>>>
>>>>
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>>
>>
>>