bug#59884: ‘gui-installed-desktop-os-encrypted’ test intermittent failures

[Mathieu Othacehe <othacehe@gnu.org>]

Hello,

> ice-9/eval.scm:619:8: Throw to key `marionette-eval-failure' with args `((quote (complete-installation installer-socket)))'.
> builder for `/gnu/store/wgw64jfyqrrg27afqmlj70a22d1mr5mv-installation.drv' failed with exit code 1
> @ build-failed /gnu/store/wgw64jfyqrrg27afqmlj70a22d1mr5mv-installation.drv - 1 builder for `/gnu/store/wgw64jfyqrrg27afqmlj70a22d1mr5mv-installation.drv' failed with exit code 1
> cannot build derivation `/gnu/store/dr20sisps9rlpbq0vfzncdiyymrd5r0i-gui-installed-desktop-os-encrypted.drv': 1 dependencies couldn't be built
>
> (From <https://ci.guix.gnu.org/build/224930/details>.)
>
> Does that ring a bell, Mathieu?

I spent days on that issue before. It used to show up on all installer
tests, and even on real hardware, then
8ce6f4dc2879919c12bc76a2f4b01200af97e01 mitigated it.

The installation is now made in a container to make sure that we are
later on able to umount the store overlay even though some background
processes such as kmscon or udev opened files from the overlay.

Now the issue only shows up on that specific test and is intermittent as
you noticed.

To be honest, that was quite painful to debug and I'm a bit scared to
jump back in. I think I had the marionette produce some lsof reports
back then, or something like that. I very much regret not to have kept
notes somewhere.

Mathieu