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

[Jaroslav Reznik]

= Proposed System Wide Change: Legacy implementations of the Java platform in 
Fedora =
https://fedoraproject.org/wiki/Changes/LegacyJDKsInFedora

Change owner(s): Jiri Vanek <jvanek at redhat.com>

Currently Fedora supports one main Java runtime and Java Development Kit (JDK) 
and from time to time one future JDK as a tech preview. This change should be 
set of rules, which will enable community to maintain legacy JDKs. Please 
note, people are bugging main JDK maintainers pretty often with this, and to 
allow them to maintain legacy JDKs is a step in right direction.

* This Change is announced after the Change Submission Deadline as an 
exception to the process. May not be approved for proposed Fedora release. *

== Detailed Description ==
This is no real work proposal. The result of this proposal is set of rules, 
which will allow community maintainers to pack any legacy jdk and will be 
ensuring that this JDKs will not conflict by any other JDK and will smoothly 
integrate to system. The results are summarized here, and pledged for 
discussion until final resolution is done.

=== Proposed rules ===
0. '''Main JDK maintainers are not never ever responsible for any legacy jdk. 
This must remain clear'''

==== option one - introducing new packages - preferred ====
1. main jdk is proclaimed as dead as it was until now.  The new jdk is derived 
as new package prviousName-legacy
 1. so from killed java-1.7.0-openjdk will become new package java-1.7.0-
openjdk-legacy
 2. next main jdk do Obsolete previous one as usually
2. new package '''must''' not do any virtual provides (aka java,java-devel)... 
(protection against random pull by as dependence)
 1. it provides only itself by name
3 its priority '''must''' be kept on less digits (right now it would be 5) 
then main jdk (protection against winning in alternatives after update)
 1. the automated check as https://bugzilla.redhat.com/show_bug.cgi?id=1189084 
are '''mandatory'''
4. at least one of the main-jdk's members '''must''' be set as comaintainer 
(to watch the commits and save the world if necessary)
5. new  package '''should''' to follow both original jdk (ideally not change 
at all (except source updates and necessary)) and current main jdk as close as 
possibly
 1. here it requires some common sense and a lot of testing if integration 
with system is as expected
6. as it is generally not new package, the review process '''should''' be only 
formal - to know maintainer and to create cvs repo 
 1. this is quite important, otherwise the new maintainer can become really 
frustrated, and we are forcing the "dead" package over"orpahned" so the full 
review (especially in alignment with rule 5) really should not be forced.
 2. on the contrary, rules agreed here '''must''' be checked.  (even the 
number 5)
7. all depending packages '''must''' keep requiring java-headless or java (and 
BuildRequires java-devel). Requirements on any exact jdk - or even worse on 
any exact legacy jdk are forbidden and needs FESCO exception. 

This option is forcing maintainers to fight with the name x current setup of 
alternatives. However, the work should be minimal. But it makes the update 
path pretty clear and it keeps users well protected against legacy jdk.

==== option two - orphaning legacy jdks and ensure update path ====
1. main JDK is only orphaned when new main JDK landed
 1. it do '''not''' Obsolate previous jdk
2. other rules (2-7) are same

This is making life of legacy JDK maintainers a bit simpler. But I don't know, 
how to ensure proper "obsolete" implementation in this case.

== Scope ==
* Proposal owners: are responsible for initial setup of those guidelines. 
The FESCO, the owners and pssible legacy JDKs maintainers have to agree on 
those rules. New legacy JDK can be then added anytime in Fedora lifecycle.
* Other developers: no developers
* Release engineering: in ideal case, no release engineer needed  
* Policies and guidelines: The proposal may split to proposal and "Legacy JDKs 
in Fedora guidelines" pages