> I know that this will cause a patch that
actually doesn't rebase cleanly onto the current HEAD at the moment to
fail the test, but isn't that a desirable feature?

I agree. I don’t think this would be a particularly difficult change to make, but I’m just wondering if there are any impacts that we have not considered, particularly for those working on larger features or refactoring work in high-traffic areas of the code-base.

> I don't think this applies to the patches currently affected by this
problem. They fail because their parent is out of date with other
repositories, not because the patch itself would somehow not apply
cleanly. If it wasn't for the CI issue these patches should be able to
get submitted (i.e. cherry-picked onto HEAD) cleanly by Gerrit without
needing another rebase, because the rebase doesn't actually change
anything about the patch itself, it just updates the parent.

Sure, I don’t mean that they would necessarily have to be rebased manually.

Chris

From: Julius Werner <jwerner@chromium.org>
Date: Monday, 15 August 2022 at 22:21
To: Chris Kay <Chris.Kay@arm.com>
Cc: Olivier Deprez <Olivier.Deprez@arm.com>, tf-a <tf-a@lists.trustedfirmware.org>, Glen Valante <glen.valante@linaro.org>, Don Harbin <don.harbin@linaro.org>, Julius Werner <jwerner@chromium.org>
Subject: Re: [TF-A] Re: TF-A CI often fail due to missing rebase

Hi Chris, Olivier,

Thanks for the detailed explanation about the interaction with other
repositories, I understand the cause of the issue better now.

However, I still feel like changing the strategy with which Jenkins
tests the patches would be an elegant and hopefully not too
complicated solution. I know that this will cause a patch that
actually doesn't rebase cleanly onto the current HEAD at the moment to
fail the test, but isn't that a desirable feature? If they don't
rebase cleanly that means the author will need to manually intervene
before submission anyway, and the CI is supposed to test whether the
patch is ready for submission, so I think it makes sense for the CI to
fail and notify the author of the problem in that case.

> It’s usually not too much hassle, though, to just rebase, given that Gerrit can usually do it automatically with the click of a button. The patches will, inevitably, have to be rebased eventually before merging anyway.

I don't think this applies to the patches currently affected by this
problem. They fail because their parent is out of date with other
repositories, not because the patch itself would somehow not apply
cleanly. If it wasn't for the CI issue these patches should be able to
get submitted (i.e. cherry-picked onto HEAD) cleanly by Gerrit without
needing another rebase, because the rebase doesn't actually change
anything about the patch itself, it just updates the parent.

I know it's just one button click, but I think the problem is more
that this issue is hard to understand for new contributors. Before you
know to click that button you first have to dig through the CI
interface, find the errors, be utterly confused why you're getting
build errors in directories completely unrelated to your patch, ask a
maintainer for help, and then be told to click the rebase button. If
there is an easy automated solution to eliminate all this unnecessary
friction, I think it would be nice to implement it.