This is another attempt at fixing the annoying nixpkgs-vet errors in CI,
which just throw with `error: SQLite database '...' is busy`.
The assumption is that this happens while initially setting up the state
directories. nixpkgs-vet runs `nix-instantiate` on both the base and the
head commit and these two could interfere.
Those checks are part of top-level/nixpkgs-basic-release-checks.nix, but
can be run in CI already to prevent regressions. The idea is to upstream
them into nixpkgs-vet eventually, but we can just as well run them as-is
in the same derivation already.
Every now and then, the nixpkgs-vet CI job currently fails with one of:
error: creating symlink
'/build/.local/share/nix/root/nix/var/nix/gcroots/profiles' ->
'/build/.local/share/nix/root/nix/var/nix/profiles': File exists
error: SQLite database
'/build/.local/share/nix/root/nix/var/nix/db/db.sqlite' is busy
It's hard to reproduce for me, so just taking a guess with the required
changes.
We have added nixpkgs-vet as a regular package to nixpkgs a while ago,
so we can now use it from pinned nixpkgs. This avoids pulling a
platform-specific binary version from upstream.
This change also allows to run the tool easily locally, the same way as
other tools:
nix-build ci -A nixpkgs-vet
This will do a full check of the repo with the exception of
nixpkgs-vet's "ratchet" checks: Those depend on having two branches to
compare, but the default is to only look at the head branch. Those
ratchet checks will still be run in CI, though.
