Re: changing tests/qtest/meson.build causes unnecessary rebuilding

[Paolo Bonzini]

On 21/01/21 15:29, Thomas Huth wrote:
> Not sure if it is related, but I noticed that we are also rebuilding a 
> lot of files in the gitlab-CI that we did not before the meson 
> conversion, especially in the check-system-* jobs, e.g:
>
> https://gitlab.com/qemu-project/qemu/-/jobs/977344949#L366
>
> The check-system-* jobs should normally take the artifacts from the 
> build-system-* jobs and thus hardly recompile anything at all.
>
> A part of the problem seems to be that we check out the submodules 
> again, I can get rid of the superfluous reconfiguration step by adding 
> something like:

Yes, there's a

[0/1] Regenerating build files.
/usr/bin/python3: can't open file 
'/builds/qemu-project/qemu/meson/meson.py': [Errno 2] No such file or 
directory

because the submodules have not been checked out, and that causes meson 
to run again.

> diff -u a/.gitlab-ci.yml b/.gitlab-ci.yml
> --- a/.gitlab-ci.yml
> +++ b/.gitlab-ci.yml
> @@ -39,6 +39,8 @@ include:
>     image: $CI_REGISTRY_IMAGE/qemu/$IMAGE:latest
>     script:
>       - cd build
> +    - touch *
> +    - make git-submodule-update
>       - find . -type f -exec touch {} +
>       - make $MAKE_CHECK_ARGS
>
> ... but still, the jobs then recompile almost all files afterwards... 
> could that be related to that meson problem, too?

No, I think it's just that, after the new checkout, the source files' 
timestamps should be quite new and cause everything to be rebuilt.

Paolo