many--nix-flake-check.yaml

name: Nix Flake Checks
# Runs `nix flake check` in matrix form on any push or pull request to the main
# branches. This is also the workflow that we will put on the readme. Since you
# shouldn't merge any PR that fails a workflow, this workflow should never fail
# on the main branches. Meaning you'll always have a pretty "CI: passing" badge
# on your README showing the quality of your work.

on:
  push:
    branches: [main, master, release, development]
  pull_request:
    branches: [main, master, release, development]
    types: [opened, synchronize, reopened]

jobs:

  build-nix-flake-check-matrix:
    name: Build the Nix flake Matrix
    runs-on: ubuntu-latest
    outputs:
      matrix: ${{ steps.set-matrix.outputs.matrix }}
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4.3.0
      - name: Install Nix
        uses: cachix/install-nix-action@v31.7.0
      - name: Generate Nix Matrix
        id: set-matrix
        run: |
          set -Eeu
          matrix="$(nix eval --json '.#githubActions.matrix')"
          echo "matrix=$matrix" >> "$GITHUB_OUTPUT"

  nix-flake-check:
    name: ${{ matrix.name }} for ${{ matrix.system }}
    timeout-minutes: 10
    needs: build-nix-flake-check-matrix
    runs-on: ${{ matrix.os }}
    strategy:
      fail-fast: false
      matrix: ${{fromJSON(needs.build-nix-flake-check-matrix.outputs.matrix)}}
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4.3.0
      - name: Install Nix
        uses: cachix/install-nix-action@v31.7.0
      - name: Add nix cache
        uses: nix-community/cache-nix-action@v6.1.3
        with:
          primary-key: nix-${{ matrix.os }}-${{ hashFiles('**/*.nix') }}
          restore-prefixes-first-match: nix-${{ matrix.os }}-
          gc-max-store-size-linux: 1073741824
          purge: false
      - name: Build derivation ${{ matrix.attr }} using Nix
        run: nix build --print-build-logs '.#${{ matrix.attr }}'