# This action uses the following secrets:
#   CACHIX_AUTH_TOKEN: Write access to nodejs.cachix.org – without it, the cache is read-only.
name: Nix files edited

on:
  push:
    branches:
      - main
      - canary
      - v[0-9]+.x-staging
      - v[0-9]+.x
    paths:
      - '**.nix'
      - tools/nix/**
      - .github/workflows/nix-changes.yml
  pull_request:
    paths:
      - '**.nix'
      - tools/nix/**
      - .github/workflows/nix-changes.yml
    types: [opened, synchronize, reopened, ready_for_review]

concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  diff:
    if: github.event.pull_request.draft == false
    strategy:
      fail-fast: false
      matrix:
        include:
          - runner: ubuntu-24.04
            system: x86_64-linux
          - runner: ubuntu-24.04-arm
            system: aarch64-linux
          - runner: macos-15-intel
            system: x86_64-darwin
          - runner: macos-latest
            system: aarch64-darwin
    name: '${{ matrix.system }}: dependencies diff'
    runs-on: ${{ matrix.runner }}
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
        with:
          fetch-depth: 2
          persist-credentials: true # We need read access in case we need to fetch in `Compute requisites before change` step
          sparse-checkout: |
            shell.nix
            tools/nix/
          sparse-checkout-cone-mode: false

      - uses: cachix/install-nix-action@75c75c31ebece974e48ebc36b4ad125bd97bd97b  # v31.11.3
        with:
          extra_nix_config: sandbox = true

      - uses: cachix/cachix-action@38b082610b782e7e93e209c35fd730d399dee866  # v17
        with:
          authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
          name: nodejs

      - name: Compute requisites after change
        run: ./tools/nix/list-requisites.sh > requisites-${{ matrix.system }}-after.list

      - name: Compute requisites before change
        run: |
          BASE_SHA="$(git rev-parse HEAD^)"
          if [ -n "$PUSH_BEFORE_SHA" ] && [ "$PUSH_BEFORE_SHA" != "$BASE_SHA" ] \
            && [ "$PUSH_BEFORE_SHA" != "0000000000000000000000000000000000000000" ] \
            && git fetch --no-tags --depth=1 origin "$PUSH_BEFORE_SHA"; then
            BASE_SHA="$PUSH_BEFORE_SHA"
          fi
          git reset "$BASE_SHA" --hard
          ./tools/nix/list-requisites.sh > requisites-${{ matrix.system }}-before.list
        env:
          PUSH_BEFORE_SHA: ${{ github.event_name == 'push' && github.event.before || '' }}

      - name: Output diff
        run: |
          {
            if diff_output="$(git diff -U0 --no-color --no-index requisites-${{ matrix.system }}-before.list requisites-${{ matrix.system }}-after.list)"; then
              echo 'No changes detected.'
            else
              echo '```diff'
              echo "$diff_output" | tail -n +5
              echo '```'
            fi
          } >> "$GITHUB_STEP_SUMMARY"

      - name: Store PR number
        if: ${{ github.event.pull_request && matrix.system == 'x86_64-linux' }}
        run: echo "${{ github.event.pull_request.number }}" > pr_number.txt

      - name: Upload requisites lists
        if: ${{ github.event.pull_request }}
        uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9  # v7.0.2
        with:
          name: requisites-${{ matrix.system }}
          path: |
            pr_number.*
            requisites-${{ matrix.system }}-before.list
            requisites-${{ matrix.system }}-after.list

  lint-nix:
    if: github.event.pull_request.draft == false
    runs-on: ubuntu-slim
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
        with:
          persist-credentials: false
          sparse-checkout: '*.nix'
          sparse-checkout-cone-mode: false
      - uses: cachix/install-nix-action@75c75c31ebece974e48ebc36b4ad125bd97bd97b  # v31.11.3
      - name: Lint Nix files
        run: |
          NIX_LINTER=$(nix-instantiate --eval --raw -E '(import ./shell.nix {}).NIX_LINTER')
          # Attempt to get it from cache, and fallback to building `devTools.nix` otherwise.
          nix-store --realise "${NIX_LINTER%/bin/*}" || nix-build -I nixpkgs=tools/nix/pkgs.nix ./tools/nix/devTools.nix --no-out-link
          "$NIX_LINTER" --quiet --ci && EXIT_CODE="$?" || EXIT_CODE="$?"
          if [ "$EXIT_CODE" != "0" ]
          then
            git --no-pager diff || true
            exit "$EXIT_CODE"
          fi