bug#50676: [core-updates-frozen] Image production is broken.

[Mathieu Othacehe]

Hello,

When a producing a disk-image, the system derivations are built twice:

--8<---------------cut here---------------start------------->8---
building /gnu/store/8w9ic3h26w6rp4pj94gd93lw2bnqywgm-system.drv...
successfully built /gnu/store/8w9ic3h26w6rp4pj94gd93lw2bnqywgm-system.drv
building /gnu/store/bxh7s2lwl82d3lwd59swkf243h17gyg1-system.drv...
successfully built /gnu/store/bxh7s2lwl82d3lwd59swkf243h17gyg1-system.drv
building /gnu/store/81wqilcd9g8c0yh6xj7chbla9agz06d9-grub.cfg.drv...
successfully built /gnu/store/81wqilcd9g8c0yh6xj7chbla9agz06d9-grub.cfg.drv
building /gnu/store/m87i36kdb09vig99q3mj24f30i1h8bjf-grub.cfg.drv...
successfully built /gnu/store/m87i36kdb09vig99q3mj24f30i1h8bjf-grub.cfg.drv
building /gnu/store/ngdkc4dhaf9qhry71dmcp1dj7rvnaqiy-partition.img.drv...
--8<---------------cut here---------------end--------------->8---

The installed Grub configuration file in /boot/grub/grub.cfg points to a
system that is *not* part of the closure. The second Grub configuration
file shown above points to the other system that *is* part of the
closure.

While booting the image in QEMU, the boot fails when trying to access
the missing /gnu/system/xxx-system/boot file.

Thanks,

Mathieu