Tiny NixOS VirtualBox appliance

olaf · January 13, 2024, 10:42am

which nix version do you use?
most likely you hit this problem:

error: path is not valid using nix ==2.18.0

opened 07:24AM - 27 Sep 23 UTC

bug

**Describe the bug** On CI, we were seeing this problem: ``` Return code: 1… Error output: these 2 derivations will be built: /nix/store/313azxr6w777rrgz0lcgkp5f0dlm2nvr-posix-toolchain.drv /nix/store/qp53d6mv3gs81akp4gv89pk9k7rb76zc-bazel-nixpkgs-posix-toolchain.drv this path will be fetched (0.09 MiB download, 0.09 MiB unpacked): /nix/store/cqam21jchkwyp7k0128g6spcx3mzv6p6-bash-5.1-p16-man error: path '/nix/store/cqam21jchkwyp7k0128g6spcx3mzv6p6-bash-5.1-p16-man' is not valid ``` This started to happen around the time when nix 2.18.0 was released. Downgrading to 2.17.0 has resolved this problem. **Steps To Reproduce** 1. clone the daml project: `git clone https://github.com/digital-asset/daml.git ` 2. `cd daml` 3. `git checkout 662a4417912df90ba9d9a99817b8ad9703480d06` # not really needed, also fails for commits from 2021 4. install nix in single-user mode: `bash <( curl -sSfL https://nixos.org/nix/install ) --no-daemon` 5. create `path_invalid.nix`: ```path_invalid.nix with import <nixpkgs> { config = {}; overlays = []; }; let # `packages` might include lists, e.g. `stdenv.initialPath` is a list itself, # so we need to flatten `packages`. flatten = builtins.concatMap (x: if builtins.isList x then x else [x]); env = buildEnv { name = "posix-toolchain"; paths = flatten [ stdenv.initialPath ]; }; cmd_glob = "${env}/bin/*"; os = if stdenv.isDarwin then "osx" else "linux"; in runCommand "bazel-nixpkgs-posix-toolchain" { executable = false; # Pointless to do this on a remote machine. preferLocalBuild = true; allowSubstitutes = false; } '' n=$out/nixpkgs_sh_posix.bzl mkdir -p "$(dirname "$n")" cat >>$n <<EOF load("@rules_sh//sh:posix.bzl", "posix", "sh_posix_toolchain") discovered = { EOF for cmd in ${cmd_glob}; do if [[ -x $cmd ]]; then echo " \'$(basename $cmd)\': \'$cmd\'," >>$n fi done cat >>$n <<EOF } def create_posix_toolchain(): sh_posix_toolchain( name = "nixpkgs_sh_posix", cmds = { cmd: discovered[cmd] for cmd in posix.commands if cmd in discovered } ) EOF '' ``` 6. run: ```bash DADE_NIXPKGS=$(pwd)/nixpkgs-snapshot if [[ ! -e "$DADE_NIXPKGS" ]]; then echo "Loading outdated or missing nixpkgs snapshot..." outpath="$( nix-store -Q --realise --indirect --add-root "$DADE_NIXPKGS" \ "$(nix-instantiate -Q --eval "nix/nixpkgs.nix" -A path \ | sed 's/^\"//;s/\"$//')" )" echo "Done loading the nixpkgs snapshot to $outpath" fi ``` 7. run: `NIX_PATH=nixpkgs=$DADE_NIXPKGS nix-build path_invalid.nix` **Expected behavior** I would expect the nix-build command to succeed. **`nix-env --version` output** ```console $ nix-env --version nix-env (Nix) 2.18.0 ``` **Additional context** I have tracked down the error message to https://github.com/NixOS/nix/blob/57eb62d2307adfd6ce881b41c861eb873153517c/src/libstore/store-api.cc#L727 **Priorities** Add :+1: to [issues you find important](https://github.com/NixOS/nix/issues?q=is%3Aissue+is%3Aopen+sort%3Areactions-%2B1-desc).

maybe downgrade nix to < 2.18