Managing parallel change in JDK 8 and JDK 9

[Chris Hegarty]

On 2 Dec 2013, at 23:36, mark.reinhold at oracle.com wrote:

> ...
> 
> By "apply independently" I mean "cherry pick"; i.e., export the patch
> for the JDK 8 changeset, apply the patch to a JDK 9 working forest,
> adjust the result as needed, build and test, and then commit a new
> changeset to JDK 9 with the same bug number and other log information.
> 
> This change will, I hope, make things clearer for everyone.  The only
> downside I can see is that it won't be possible to build JDK 8 GA from
> a JDK 9 forest since the latter will fork from JDK 8 prior to GA.  It's

Provided that engineers forward port JDK8 changes to JDK9 in a timely manner, then 'hg import --exact' can be used. Since JDK9 will contain the parent change set. That way tag changesets could also be forward ported, when  'hg import --exact' detects that the parent is a tag changeset that is not currently in JDK9. All tags up to and inclusing JDK8 FCS would then be applicable in the JDK9 forest.

But every engineer would have to follow this ( use --exact ). Probably not practical, but worth considering ( if not already done so ).

-Chris.

> somewhat convenient -- and kind of cool -- to be able to do that, but I
> think it has more aesthetic than technical value.  You can't build a JDK
> 7 Update release from a JDK 8 forest; this situation is no different.
> 
> (There might be a way to merge JDK 8 GA into JDK 9, for the historical
> record, using named-branch trickery and some jcheck refinements, but
> that's something we can always do after the fact.)
> 
> Comments?
> 
> - Mark