F22 System Wide Change: Legacy implementations of the Java platform in Fedora

[Mikolaj Izdebski]

On 02/24/2015 04:06 PM, Deepak Bhole wrote:
> * Mikolaj Izdebski <mizdebsk at redhat.com> [2015-02-24 09:58]:
>> On 02/24/2015 03:32 PM, Deepak Bhole wrote:
>>> * Dominik 'Rathann' Mierzejewski <dominik at greysector.net> [2015-02-24 09:29]:
>>>> On Tuesday, 24 February 2015 at 15:09, Deepak Bhole wrote:
>>>>> * Dominik 'Rathann' Mierzejewski <dominik at greysector.net> [2015-02-24 09:04]:
>>>>>> On Tuesday, 24 February 2015 at 14:28, Jiri Vanek wrote:
>>>>>> [...]
>>>>>>> There were several attempts in past like "can you please support jdk
>>>>>>> 7,6...in newer fedoras" and we always told no. When come speech about "do it
>>>>>>> on your own" suddenly many questions marks raised up.
>>>>>>>
>>>>>>> The last open bug is: https://bugzilla.redhat.com/show_bug.cgi?id=1190137
>>>>>>> the guy is willing to maintain it.
>>>>>>
>>>>>> Fine, so let him do it and drop the Obsoletes: tag in java-1.8.0-openjdk
>>>>>> and its successors. You shouldn't arbitrarily block people from
>>>>>> re-introducing an older branch of any package back into Fedora in the
>>>>>> first place.
>>>>>>
>>>>>
>>>>> We have no intention of blocking it. The reason for proposing these
>>>>> restrictions is that the Fedora Java stack will not work with older
>>>>> JDKs, therefore we need to make sure that it goes not get installed on
>>>>> the system unless explicitly requested by someone who knows what they
>>>>> are doing.
>>>>
>>>> Well, you do that by adding/updating (Build)Requires: in the packages
>>>> which won't work otherwise, not by adding Obsoletes:.
>>>>
>>>
>>> That would generally work for most packages, but there is a new JDK
>>> released every 2 years. This means that we would have to change the BR
>>> and Requires for the entire Java stack (100s and 100s of packages) every
>>> 2 years, which is non-trivial.
>>
>> First, we have versioned auto-requires generated during package build.
>> Explicit requires on java aren't usually needed. If package requires
>> "java > 1:1.7" then it is correct - the package can be assumed to work
>> with older JDK.
>>
> 
> While that is true in terms of source compatibility, it will work only
> if it is compiled with the older JDK.
> 
>> Secondly, it is fairly easy to add requires on "java-devel >= 1:1.8" to
>> packages related to build systems like ant, maven or gradle. This would
>> cover most cases of building Java packages using latest JDK.
>>
> 
> As you stated, it will cover most cases, but not all. More critically,
> this does not solve the issue with requirement of 'java' itself.

These few remaining cases can be easily handled by provenpackager as
mass-change.

Also, my proposal of introducing "java" metapackage (see my other post
in this thread), which would always require the latest JDK, solves this
problem in a different way, without modifying ordinary Java packages at all.

-- 
Mikolaj Izdebski
Software Engineer, Red Hat
IRC: mizdebsk