RFR: Section on backporting [v6]

[Goetz Lindenmaier]

On Thu, 25 Nov 2021 18:17:46 GMT, Jesper Wilhelmsson <jwilhelm at openjdk.org> wrote:

>> Guidance on backporting.
>> Also moved "Backing out a change" to the testing section where I believe it fits better. This section is unchanged.
>
> Jesper Wilhelmsson has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update src/index.md
>   
>   Co-authored-by: Andrew Haley <aph-open at littlepinkcloud.com>

A general remark wrt. backouts:
One thing I have always been wondering about: 
What to do if a backported issue is backed out?
For an example see JDK-8274338. It was backported
to 11.0.14 but then backed out again as JDK-8276943.
Nevertheless in JBS the original issue is marked as backported 
to 11.0.14.
Should we advise to remove this link, and change
the backport issue and the backout issue to 
bugs?
I think this would make obvious that the issue is NOT 
fixed in the older release (here 11.0.14).

src/index.md line 1501:

> 1499: 
> 1500: In order to be allowed to push a change to one of the OpenJDK Update Release repositories, an approval is required. The [official process for how to request push approval for a backport](https://openjdk.java.net/projects/jdk-updates/approval.html) describes in detail how to work with JBS when requesting approvals. In short, there's a label `jdk<release>u-fix-request` that should be added to the main JBS issue. Also put a motivation as to why the issue needs to be backported as a comment in the main issue. Once the label and motivation has been added, wait for the maintainers of the release to approve your request. The approval will be indicated with a label, `jdk<release>u-fix-yes`, added to the main issue.
> 1501: 

Hi,
I would propose to differ the development and release
repositories most update projects use (like jdk11u-dev and jdk11u).

In this case, in the first sentence, it should say 
"... OpenJDK Update **Development** repositories ..."

and at the end you could add
  If an update is in rampdown in the Release repository, 
  urgent fixes need to be approved with
  `jdk<release>u-critical-request` / `jdk<release>u-critical-yes`.

If you want to keep it short, omitting this is ok.  But this is 
also missing on the "JDK Updates: Requesting push approval for fixes"
wiki page referred to from here.

-------------

Changes requested by goetz (no project role).

PR: https://git.openjdk.java.net/guide/pull/66