Playing with Nix on Gitlab CI

.gitlab-ci.yml

---
image: ${CI_DEPENDENCY_PROXY_GROUP_IMAGE_PREFIX}/nixos/nix:2.17.0

variables:
    COMPOSER_ALLOW_SUPERUSER: 1

default:
    before_script:
        - echo experimental-features = nix-command flakes >> /etc/nix/nix.conf
        - echo access-tokens = github.com=${GITHUB_TOKEN} >> /etc/nix/nix.conf
        - |
            cat > flake.nix << EOF
            {
            description = "Gitlab CI devshell";

            inputs = {
              nixpkgs.url = "github:NixOS/nixpkgs/4b0ef51702e1512880179cd24e9e63b88f0a2121";
            };

            outputs = inputs@{ self, flake-parts, ... }:
              flake-parts.lib.mkFlake { inherit inputs; } {
                systems = [ "x86_64-linux" ];

                perSystem = { config, pkgs, system, ... }:
                    let
                      php = pkgs.php.withExtensions ({ enabled, all }: enabled ++ [ all.xsl all.pcov ]);
                    in
                    {
                      packages.default = pkgs.buildEnv {
                        name = "gitlab-ci";
                        paths = [
                            php
                            php.packages.composer
                            pkgs.nodePackages.prettier
                        ];
                      };
                    };
                };
            }
            EOF
        - git add .
        - nix profile install .

stages:
    - test

Unit tests:
    stage: test
    script:
        - composer install
        - composer grumphp

Prettier checks:
    stage: test
    script:
        - prettier --check .