[Mesa-dev] How to merge Mesa changes which require corresponding piglit changes

[Mark Janes]

Michel Dänzer <michel at daenzer.net> writes:

> Now that the GitLab CI pipeline tests a snapshot of piglit with llvmpipe
> (https://gitlab.freedesktop.org/mesa/mesa/merge_requests/2468), the
> question has come up how to deal with inter-dependent Mesa/piglit
> changes (where merging only one or the other causes some piglit
> regressions).
>
>
> First of all, let it be clear that just merging the Mesa changes as-is
> and breaking the GitLab CI pipeline is not acceptable.
>
>
> From the Mesa POV, the easiest solution is:
>
> 1. Merge the piglit changes
> 2. In the Mesa MR (merge request), add a commit which updates piglit[0]
> 3. If the CI pipeline is green, the MR can be merged
>
>
> In case one wants to avoid alarms from external CI systems, another
> possibility is:

For the Intel CI, no alarm is generated if the piglit test is pushed
first.  Normal development process includes writing a piglit test to
illustrate the bug that is being fixed.

> 1. In the Mesa MR, add a commit which disables the piglit tests broken
> by the Mesa changes.
> 2. If the CI pipeline is green, the MR can be merged
> 3. Merge the piglit changes
> 4. Create another Mesa MR which updates piglit[0] and re-enables the
> tests disabled in step 1
>
> I hope that covers it, don't hesitate to ask questions if something's
> still unclear.

It might help developers if CI generated the patch to make their pipeline
pass.

> [0] How to update piglit in the CI pipeline:
>
> * Change the commit hash on the "git checkout" line in
> .gitlab-ci/debian-test-install.sh[1] to a later commit from the piglit
> master branch
> * Bump DEBIAN_TEST_TAG[1] in .gitlab-ci.yml to the current date
> * May also need to update .gitlab-ci/piglit/*.txt to match any expected
> changes in test results
>
> See https://gitlab.freedesktop.org/mesa/mesa/merge_requests/2748 for an
> example.
>
>
> [1] Might soon be .gitlab-ci/container/x86_test.sh and DEBIAN_TAG in the
> x86_test job definition, respectively, once
> https://gitlab.freedesktop.org/mesa/mesa/merge_requests/2722 is merged.
>
>
> -- 
> Earthling Michel Dänzer               |               https://redhat.com
> Libre software enthusiast             |             Mesa and X developer
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