Workshop proposal: How to do backports/bug fixes properly?

[Severin Gehwolf]

On Fri, 2019-01-18 at 11:13 +0100, Severin Gehwolf wrote:
> With the new fast-release cycle it's hard to know where fixes should
> get pushed in certain phases of the development cycle. Let's exclude
> enhancements for this discussion for simplicity.
> 
> Consider the fast-release-cadence cycle:
> 
> ---------------------------------------------------------------------------------------
>                              ,- JDK 12,     ,- JDK 12,     ,-- JDK 12 GA
> Time:                        |  RDP 1       | RDP 2        |
>                             \|/            \|/            \|/
>                              `              `              `
> ---------------------------------------------------------------------------------------
> 
> 
>                 ,--jdk-updates/jdk11u----                   ,--------jdk-updates/jdk12u
>  ,---jdk/jdk11-+              ,------------jdk/jdk12-------+ 
> +----------------------------+-----------------------jdk/jdk---------------------------
> 
> 
> We are currently between JDK 12, RDP 1 and JDK 12, RDP 2. So if a
> bugfix is being developed it's not entirely clear where to push the fix
> to. Should it go to jdk/jdk, or jdk/jdk12? Do all bugfixes go to
> jdk/jdk12 directly before RDP 2? Would I need to push it to both,
> jdk/jdk and jdk/jdk12?
> 
> What if the fix needs to go to JDK 11 too? It's possible for a fix to
> be in jdk/jdk and jdk-updates/jdk11u, but not in jdk/jdk12 because of
> some RDP 2 rules where only high priority bugs can be fixed. This might
> cause issues where JDK 12 could potentially regress if the developer
> forgets to revisit the backport for jdk-updates/jdk12u once that tree
> exists.
> 
> Who gets to decide which fix gets pushed where?
> 
> If a backport depends on other fixes getting backported too, what's the
> process to get it included? Should the backport merged changes? Keep
> them separate as much as possible? Where do we draw the line?
> 
> Perhaps we could discuss those issues and set some ground rules. Trying
> to simplify the process would help too.

FYI:

At the workshop in February I've volunteered to write some guidance
document. Here it is:

https://wiki.openjdk.java.net/display/JDKUpdates/JDK+Updates+Guidance

Feel free to edit/comment/etc.

Thanks,
Severin