bug#42371: Grafts max out build slots without being queued

["Ludovic Courtès" <ludo@gnu.org>]

Hi,

Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:

> While working on ruby-asciidoctor-pdf, the following command failed
> because of maxing out build users:
>
> ./pre-inst-env guix build --quiet --keep-going --check ruby_version@1.0.2 gnome-shell-extension-gsconnect@33 numix-gtk-theme@2.6.7 arc-theme@20190917 gnome@3.34.2 ruby-fakefs@1.2.2 ruby-protobuf@3.10.3 ruby-fast-gettext@2.0.3 ruby-sass-rails@5.0.7 mailcatcher@0.7.1 ruby-rspec-its@1.3.0 warzone2100@3.4.0 keepassxc@2.6.0 wsjtx@2.2.2 js8call@2.2.0 ruby-yard-with-tests@0.9.25 ruby-asciidoctor-pdf@1.5.3-1.f25ea78 ruby-web-console@3.7.0 ruby-autoprefixer-rails@9.4.7 ruby-jekyll-paginate-v2@2.0.0 ruby-solargraph@0.36.0 --max-jobs=1
> The following derivations will be built:
>    /gnu/store/w5qba9nzswv7ysrlxfwcqdvrf9vsgbk6-ruby-jekyll-paginate-v2-2.0.0.drv
>    /gnu/store/4r1ziw3cb5n5jgknd1jfsvdl46cz56f9-ruby-autoprefixer-rails-9.4.7.drv
>    /gnu/store/2f674244hhb399p86z15zgv246sj78gr-ruby-web-console-3.7.0.drv
>    /gnu/store/sqy6f63vzgbyk6jg1zigxvks9g365wfs-ruby-rspec-its-1.3.0.drv
>    /gnu/store/zz34dh2q37r21r2d26k7z5rpryysc3km-ruby-sass-rails-5.0.7.drv
>    /gnu/store/62nlbfwd2jf01nm0p0wlc9sgvn5yp6gc-ruby-fakefs-1.2.2.drv
>    /gnu/store/pjdh08jh7pxlfm4dcz86bg5xqbjyf4lm-gnome-3.34.2.drv
>    /gnu/store/xqdvar6gmkz28003md4w9c1mqvg0slas-arc-theme-20190917.drv
>    /gnu/store/qwmj9b493ays4dvgkmniq61fnxg3claw-numix-gtk-theme-2.6.7.drv
>    /gnu/store/s112ayw6qg86y7j45r5yslfl151ngvgn-ruby_version-1.0.2.drv
> The following grafts will be made:
>    /gnu/store/ww8blyc1nkf788jjb3anh22dylibvbah-ruby-solargraph-0.36.0.drv
>    /gnu/store/c7bfyqfq8d7imgy8il7wzqpx3qpx4zpw-ruby-asciidoctor-pdf-1.5.3-1.f25ea78.drv
>    /gnu/store/cf501w2kdgw6k2gv6n24ikhzww8f51x7-ruby-yard-with-tests-0.9.25.drv
>    /gnu/store/da8hhcaj20z06f2kww0sg4y24ma034dy-js8call-2.2.0.drv
>    /gnu/store/zn1jkg86fpji54s0pa0lfnf1dy00s2nh-wsjtx-2.2.2.drv
>    /gnu/store/77g250mf14rskilpsggn070y4fjrbngx-keepassxc-2.6.0.drv
>    /gnu/store/5k393vfm5qw442ya7v061q5fmjvhhcs5-warzone2100-3.4.0.drv
>    /gnu/store/5d4h76qsr0rmbkn2c0zilyjr7mpzk5pd-mailcatcher-0.7.1.drv
>    /gnu/store/mxm64sm569fyhdmxh6jlvdl18fwdb6f6-ruby-fast-gettext-2.0.3.drv
>    /gnu/store/wglga3r1j6x87hqksrh5d1ra70kl729l-ruby-protobuf-3.10.3.drv
>    /gnu/store/73nw9dxmmp8jykhmzwdpc3wk7mn81yal-gnome-shell-extension-gsconnect-33.drv
> guix build: error: all build users are currently in use; consider
> creating additional users and adding them to the `guixbuild' group

Presumably here it’s running one job at a time, so I don’t think it can
end up using more than one build user.

What does “guix processes” return when that happens?  Could it be that
some other Guix clients are running?

Thanks,
Ludo’.