There is absolutely no good reason these should show up in NARs besides
misconfigured systems and as long as the case hack exists, unpacking
such a NAR will cause its repacking to be wrong on systems with case
hack enabled.
This should not have any security impact on Lix to fix, but it was one
of the vectors for CVE-2024-45593:
https://github.com/NixOS/nix/security/advisories/GHSA-h4vv-h3jq-v493
Change-Id: I85b6075aacc069ee7039240b0f525804a2d8edcb
This also rewrites a lot of the command handling in the fixtures
library, since we want to more precisely control which way that the nix
store is set up in the tests, rather than the previous method of
renaming /nix/store to some temp dir (which allows builds but does not
allow any /nix/store paths or stability across runs, which is a
significant issue for snapshot testing).
It uses a builder to reduce the amount of state carelessly thrown
around.
The evil NARs are inspired by CVE-2024-45593
(https://github.com/NixOS/nix/security/advisories/GHSA-h4vv-h3jq-v493).
No bugs were found in this endeavor.
Change-Id: Iee41b055fa96529c5a3c761f680ed1d0667ba5da
jade