Flake issues # error: program 'git' failed with exit code 128

  • system: "x86_64-linux"
  • host os: Linux 6.1.34, NixOS, 23.05 (Stoat), 23.05.1092.c7ff1b9b956
  • multi-user?: yes
  • sandbox: yes
  • version: nix-env (Nix) 2.13.3
  • channels(root): "nixgl, nixos-23.05, nixos-hardware"
  • channels(usera): ""
  • nixpkgs: /nix/var/nix/profiles/per-user/root/channels/nixos

  description = "A simple Go package";

  # Nixpkgs / NixOS version to use.
  inputs.nixpkgs.url = "nixpkgs/nixos-${nixosVersion}";

  outputs = { self, nixpkgs }:

      # Generate a user-friendly version number.
      version = builtins.substring 0 8 self.lastModifiedDate;

      # System types to support.
      supportedSystems = [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ];

      # Helper function to generate an attrset '{ x86_64-linux = f "x86_64-linux"; ... }'.
      forAllSystems = nixpkgs.lib.genAttrs supportedSystems;

      # Nixpkgs instantiated for supported system types.
      nixpkgsFor = forAllSystems (system: import nixpkgs { inherit system; });


      # Provide some binary packages for selected system types.
      packages = forAllSystems (system:
          pkgs = nixpkgsFor.${system};
          # The default package for 'nix build'. This makes sense if the
          # flake provides only one package or there is a clear "main"
          # package.
          default = pkgs.buildGoModule {
            pname = "go-hello";
            inherit version;
            # In 'nix develop', we don't need a copy of the source tree
            # in the Nix store.
            src = ./.;

            # This hash locks the dependencies of this package. It is
            # necessary because of how Go requires network access to resolve
            # VCS.  See https://www.tweag.io/blog/2021-03-04-gomod2nix/ for
            # details. Normally one can build with a fake sha256 and rely on native Go
            # mechanisms to tell you what the hash should be or determine what
            # it should be "out-of-band" with other tooling (eg. gomod2nix).
            # To begin with it is recommended to set this, but one must
            # remeber to bump this hash when your dependencies change.
            #vendorSha256 = pkgs.lib.fakeSha256;

            vendorSha256 = "sha256-pQpattmS9VmO3ZIQUFn66az8GSmB4IvYhTTCFn6SUmo=";

nix flake metadata

fatal: unable to read 0dcc561e038fbc9141d14843df255f69ba1584eb
error: program 'git' failed with exit code 128
(use '--show-trace' to show detailed location information)

nix-shell Nix_buildEnv_flake__test_go.nix

error: undefined variable 'nixosVersion'

       at /home/ae/ae_share_VM/z_DS_setup/toolbox/nixMachNixEnv/testingMachNix/Nix_buildEnv_flake__test_go.nix:8:41:

            7|   # Nixpkgs / NixOS version to use.
            8|   inputs.nixpkgs.url = "nixpkgs/nixos-${nixosVersion}";
             |                                         ^

How to set variables for flakes before output (let in)?

How to get it working?

You can’t.

The flake.nix looks like nix code, but actually is a very limited subset when it is evaluated as a flake.

  1. You can’t use dynamic values in the inputs or description (and probably nixConfig as well)
  2. The top-level expression has to be a set, you can’t wrap it in a let/in
  3. You can’t even eta reduce the outputs function with something imported.

mh, thanks for that information

still I don’t know, how it could work

inputs rec { 
    nixpkgs.url = "nixpkgs/nixos-${nixosVersion}";

fails, as well

I said that, and I mean it.

PS: The thread title doesn’t really match the question, do you mind updating it?