flake.nix: Add flakeModule

[roberth]

Makes devenv usable for flake-parts users.

[montchr]

When using devenv via the flake module, assuming that the devenv CLI isn't available, how would I run processes/services defined in configuration?

[montchr]

On that note, it would be pretty amazing to expose the process runners and/or the direct commands they execute via flake.apps

[montchr]

assuming that the devenv CLI isn't available

Bad assumption -- I just checked out this branch (after rebasing onto main) and I see that the CLI is available. However, when I run devenv up:

✦ ❯ devenv up
File devenv.nix does not exist. To get started, run:

  $ devenv init

[roberth]

I accidentally shadowed the shim by adding the whole devenv package to the packages. That was old code from before the shim existed. Now the module is on par with the existing flake integration.

[terlar]

How to propagate the pre-commit-hooks.nix flake-parts integration into devenv, I tried to do something like this:

{
  perSystem = {config, ...}: {
    devenv.shells.default = {
      pre-commit = {
        inherit (config.pre-commit.settings) hooks settings;
      };
    };
  };
}

But all the settings end up being repeated/merged, e.g. the generated YAML file:

...
        {
          "entry": "/nix/store/d1x69xig1bwbk8xpn35zw6lcizdwnyhh-statix-0.5.6/bin/statix check -o errfmt /nix/store/d1x69xig1bwbk8xpn35zw6lcizdwnyhh-statix-0.5.6/bin/statix check -o errfmt ",
          "exclude": "^$^$",
          "files": "\\.nix$\\.nix$",
          "id": "statix",
          "language": "systemsystem",
          "name": "statixstatix",
          "pass_filenames": false,
          "stages": [
            "commit",
            "commit"
          ],
          "types": [
            "file",
            "file"
          ],
          "types_or": []
        },
...

[terlar]

For now my workaround was to not use the integration, but instead just add the hook via a script:

{
  perSystem = {config, ...}: {
    devenv.shells.default = {
      enterShell = config.pre-commit.installationScript;
    };
  };
}

[roberth]

Just did a trivial rebase to update the CI config and hopefully fix the CI, but looks like it needs to be approved.

[srid]

Out of curiosity, why does devenv require --impure?

[montchr]

I've also been curiously wondering about this.

[montchr]

Related: #330

[roberth]

Unclear to me too, but this is just inherited from the existing flake integration.

[nazarewk]

I'm getting same error as reported in #495 with latest commit of this PR, here is my complete flake.nix:

error: Function called without required argument "system" at /nix/store/l5m6bhcq0g2rz0pfkqqrk4ix72grs0s8-source/src/modules/mkNakedShell.nix:27, did you mean "mystem", "systemc" or "systemd"?

{
  description = "Description for the project";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    # devenv.url = "github:cachix/devenv/latest";
    # see https://github.com/cachix/devenv/pull/360
    devenv.url = "github:cachix/devenv/9f761946802870fcbfd5710cd722b568971e057a";
  };

  outputs = inputs@{ flake-parts, ... }:
    flake-parts.lib.mkFlake { inherit inputs; } {
      imports = [
        inputs.devenv.flakeModule
      ];
      systems = [ "x86_64-linux" "i686-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ];

      perSystem = { config, self', inputs', pkgs, system, ... }: {
        # Per-system attributes can be defined here. The self' and inputs'
        # module parameters provide easy access to attributes of the same
        # system.

        # Equivalent to  inputs'.nixpkgs.legacyPackages.hello;
        packages.default = pkgs.hello;

        devenv.shells.default = {
          # https://devenv.sh/reference/options/
          packages = [ config.packages.default ];

          enterShell = ''
            hello
          '';
        };

      };
      flake = {
        # The usual flake attributes can be defined here, including system-
        # agnostic ones like nixosModule and system-enumerating ones, although
        # those are more easily expressed in perSystem.

      };
    };
}

[roberth]

@nazarewk How did you invoke it?

nix build and nix develop work for me. The error seems unrelated.

[nazarewk]

@nazarewk How did you invoke it?

nix build and nix develop work for me. The error seems unrelated.

The error is indeed unrelated to your changes, updated my issue #495 to reflect that.

I just tried direnv reload

update: nix develop work just fine

[roberth]

Rebased, tests pass locally (workflow needs approval), added the containers as packages.

@domenkozar wdyt?