RFR: 1797: Add support for /backport pull request command

[David Holmes]

On 2/02/2023 9:33 pm, Erik Duveblad wrote:
>> On 2 Feb 2023, at 09:28, Thomas Stüfe <thomas.stuefe at gmail.com> wrote:
>>
>>> 1. If the `/backport` command is used in an **open** pull request, it adds a label `Backport=repo:branch` to the PR. If the PR is later integrated, the PR bot scans for backport labels and begins the backporting process. To cancel the backport, the user can use `/backport disable repo master` to remove the label before the PR is integrated.
>>
>> This does not sound desirable. Fixes should undergo some bake time in
>> the primary repo before they get backported anywhere. With the current
>> situation it is up to the person doing the backport to go to the commit
>> in question and know that the commit has been suitable tested/baked.
>>
>> David
>> -----
>>
>>
>> I agree with David. Making it easy to downport fresh changes right away is not something we should encourage.
> 
> Please do not jump to conclusions about what Zhao is proposing without understanding the patch :) Zhao’s patch is only making it easier to create a backport _pull request_, it will not automatically create any backport commits.

Okay I misconstrued what "begins the backporting process" actually 
meant. Sorry for the false alarm.

> A user can already today type `/backport` in a commit comment for
> the commit a pull request resulted in once it was integrated. This can be
> done only seconds after the pull request was integrated and the Skara
> bots will then go ahead and create a “backport pull request” (see the
> Skara wiki on backports for more details [0]). Zhao’s patch only removes
> the manual step of having to navigate to the GitHub page for the
> resulting commit and add a commit comment. With Zhao’s patch a user can
> now instead type `/backport` in the pull request and the Skara bots will
> create the “backport pull request” once the pull request has been
>integrated.

Sure. And I understand better this isn't really trying to allow (though 
it does) the ability to type:

/integrate
/backport ...

in a PR but more dealing with the common(?) problem that when someone 
does decide to backport a change they tend to go to the JBS issue, see 
the PR link, go to the PR and type "/backport ..." only to be told they 
are in the wrong place and need to go to the commit. I know I've done it 
myself :)

Cheers,
David
-----

> 
> So, this patch is not creating any new workflows, it is just removing a couple of manual steps needed today to create a "backport pull request". The "backport pull request" should of course not be integrated until the commit in mainline has received proper “soak time” and testing.
> 
> Thanks,
> Erik
> 
> [0]: https://wiki.openjdk.org/display/SKARA/Backports
>