Revert "switch to buildbot"

This reverts commit d6ae2ad.

I don't want to use buildbot when there is no good reason to.
It makes it harder for others to work on the CI and makes it unfriendly for forks.

Author: adisbladis

.envrc

@@ -0,0 +1 @@
+use flake

.github/workflows/ci.yml

@@ -5,19 +5,57 @@ on:
   merge_group:
   push:
     branches:
+      - master
       - main
 
 jobs:
+  nix-matrix:
+    runs-on: ubuntu-latest
+    outputs:
+      matrix: ${{ steps.set-matrix.outputs.matrix }}
+    steps:
+      - uses: actions/checkout@v5
+      - uses: cachix/install-nix-action@v31
+      - id: set-matrix
+        name: Generate Nix Matrix
+        run: |
+          set -Eeu
+          echo "matrix=$(nix eval --json '.#githubActions.matrix')" >> "$GITHUB_OUTPUT"
+
+  nix-build:
+    needs: nix-matrix
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix: ${{fromJSON(needs.nix-matrix.outputs.matrix)}}
+    steps:
+      - uses: actions/checkout@v5
+      - uses: cachix/install-nix-action@v31
+      - run: nix build -L ".#${{ matrix.attr }}"
+
   nix-unit:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5
       - name: Install Nix
+<<<<<<< HEAD:.github/workflows/ci.yml
         uses: cachix/install-nix-action@v31
       - uses: DeterminateSystems/magic-nix-cache-action@main
+=======
+        uses: DeterminateSystems/nix-installer-action@v19
+      - name: Build shell
+        run: nix develop -c true
+>>>>>>> parent of d6ae2ad (switch to buildbot):.github/workflows/nix-github-actions.yml
       - name: Test nix-unit
         run: nix develop -c ./tests/tests.py
 
+  collect:
+    runs-on: ubuntu-latest
+    needs:
+      - nix-build
+      - nix-unit
+    steps:
+      - run: exit 0
+
   deploy-pages:
     if: github.ref == 'refs/heads/main'
     runs-on: ubuntu-latest

flake.lock

@@ -7,28 +7,37 @@
     flake-parts.inputs.nixpkgs-lib.follows = "nixpkgs";
     treefmt-nix.url = "github:numtide/treefmt-nix";
     treefmt-nix.inputs.nixpkgs.follows = "nixpkgs";
+    nix-github-actions.url = "github:nix-community/nix-github-actions";
+    nix-github-actions.inputs.nixpkgs.follows = "nixpkgs";
   };
 
   outputs =
-    inputs@{ flake-parts, ... }:
+    inputs@{ flake-parts, nix-github-actions, ... }:
     let
       inherit (inputs.nixpkgs) lib;
       inherit (inputs) self;
     in
     flake-parts.lib.mkFlake { inherit inputs; } {
-      systems = [
-        "x86_64-linux"
-        "aarch64-linux"
-        "aarch64-darwin"
-        "x86_64-darwin"
-      ];
+      systems = inputs.nixpkgs.lib.systems.flakeExposed;
       imports = [
         inputs.flake-parts.flakeModules.modules
         inputs.flake-parts.flakeModules.partitions
         ./lib/modules.nix
         ./templates/flake-module.nix
       ];
 
+      flake.githubActions = nix-github-actions.lib.mkGithubMatrix {
+        checks = {
+          x86_64-linux = builtins.removeAttrs (self.packages.x86_64-linux // self.checks.x86_64-linux) [
+            "default"
+          ];
+          x86_64-darwin = builtins.removeAttrs (self.packages.x86_64-darwin // self.checks.x86_64-darwin) [
+            "default"
+            "treefmt"
+          ];
+        };
+      };
+
       flake.lib = import ./lib { inherit lib; };
 
       perSystem =