Re: Test parallelism with CMake

[Greg Hogan <code@greghogan.com>]

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On Fri, Oct 29, 2021 at 8:09 AM Ludovic Courtès <ludo@gnu.org> wrote:

> Hi Greg,
>
> Greg Hogan <code@greghogan.com> skribis:
> > It seems that we should at a minimum document the issue in
> > cmake-build-system:check. We could patch cmake-build-system to enable
> test
> > parallelism and explicitly disable that setting for packages which
> succeed
> > before but fail after making the change. What do you think?
>
> I think we could make the change you made—running ‘ctest’—in
> ‘core-updates’.  If it turns out to be safer, we can have
> #:parallel-build? default to #f at the beginning in
> ‘cmake-build-system’.
>
> How does that sound?
>

Hi Liliana and Ludo’,

If the default is to disable parallel tests then it is unlikely that future
committers will be aware of, remember, and bother to enable the setting.
And once packages do override the default then there would be additional
future work to invert the default value.

I do not know how to obtain the list of packages using the
cmake-build-system.

The strategy looks to require multiple stages. First build and test the
packages and ignore current failures. As noted by Liliana, next build and
test the successful builds with ctest in serial. Hopefully no or few builds
are newly failing at this point. Lastly build and test with ctest in
parallel, and explicitly disable test parallelism for the failing builds.

Greg

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