ci.yaml

name: CI

# Controls when the action will run.
on:
  # Triggers the workflow on push or pull request events but only for the main branch
  push:
    branches: [main]
  pull_request:
    branches: [main]

  # Allows you to run this workflow manually from the Actions tab
  workflow_dispatch:

jobs:
  # matrix-prep-* steps dynamically generate a bit of JSON depending on whether our action has
  # access to repository secrets. When running on a pull_request from a fork, the author is
  # untrusted so the secret will be absent. Insanely complex for how simple this requirement is...
  # inspired from
  # https://stackoverflow.com/questions/65384420/how-to-make-a-github-action-matrix-element-conditional

  matrix-prep-bazelversion:
    # Prepares the 'bazelversion' axis of the test matrix
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - id: bazel_6
        run: echo "bazelversion=$(head -n 1 .bazelversion)" >> $GITHUB_OUTPUT
      - id: bazel_5
        run: echo "bazelversion=5.3.2" >> $GITHUB_OUTPUT
    outputs:
      # Will look like ["<version from .bazelversion>", "5.3.2"]
      bazelversions: ${{ toJSON(steps.*.outputs.bazelversion) }}

  matrix-prep-os:
    # Prepares the 'os' axis of the test matrix
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - id: linux
        run: echo "os=ubuntu-latest" >> $GITHUB_OUTPUT
      - id: macos
        run: echo "os=macos-latest" >> $GITHUB_OUTPUT
        # Only run on main branch (not PRs) to minimize macOS minutes (billed at 10X)
        # https://docs.github.com/en/billing/managing-billing-for-github-actions/about-billing-for-github-actions#included-storage-and-minutes
        if: ${{ github.ref == 'refs/heads/main' }}
      - id: windows
        run: echo "os=windows-latest" >> $GITHUB_OUTPUT
        # Only run on main branch (or PR branches that contain 'windows') to minimize Windows minutes (billed at 2X)
        # https://docs.github.com/en/billing/managing-billing-for-github-actions/about-billing-for-github-actions#included-storage-and-minutes
        if: ${{ github.ref == 'refs/heads/main' || contains(github.head_ref, 'windows') }}
    outputs:
      # Will look like ["ubuntu-latest", "macos-latest", "windows-latest"]
      os: ${{ toJSON(steps.*.outputs.os) }}

  test:
    # The type of runner that the job will run on
    runs-on: ${{ matrix.os }}

    needs:
      - matrix-prep-bazelversion
      - matrix-prep-os

    strategy:
      fail-fast: false
      matrix:
        os: ${{ fromJSON(needs.matrix-prep-os.outputs.os) }}
        bazelversion: ${{ fromJSON(needs.matrix-prep-bazelversion.outputs.bazelversions) }}
        bzlmodEnabled: [true, false]
        folder:
          - '.'
          - 'e2e/smoke'
          - 'e2e/npm-links'
          - 'e2e/sourcemaps'
          - 'e2e/tsconfig'
          - 'e2e/bundle'
        exclude:
          # Don't test macos with Bazel 5 to minimize macOS minutes (billed at 10X)
          # https://docs.github.com/en/billing/managing-billing-for-github-actions/about-billing-for-github-actions#included-storage-and-minutes
          - os: macos-latest
            bazelversion: 5.3.2
          # Don't test bzlmod with Bazel 5 (not supported)
          - bazelversion: 5.3.2
            bzlmodEnabled: true
          # Don't test Windows with Bazel 5 to minimize Windows minutes (billed at 2X)
          - bazelversion: 5.3.2
            os: windows-latest

    # Steps represent a sequence of tasks that will be executed as part of the job
    steps:
      # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
      - uses: actions/checkout@v3

      # Cache build and external artifacts so that the next ci build is incremental.
      # Because github action caches cannot be updated after a build, we need to
      # store the contents of each build in a unique cache key, then fall back to loading
      # it on the next ci run. We use hashFiles(...) in the key and restore-keys- with
      # the prefix to load the most recent cache for the branch on a cache miss. You
      # should customize the contents of hashFiles to capture any bazel input sources,
      # although this doesn't need to be perfect. If none of the input sources change
      # then a cache hit will load an existing cache and bazel won't have to do any work.
      # In the case of a cache miss, you want the fallback cache to contain most of the
      # previously built artifacts to minimize build time. The more precise you are with
      # hashFiles sources the less work bazel will have to do.
      - name: Mount bazel caches
        uses: actions/cache@v3
        with:
          path: |
            "~/.cache/bazel"
            "~/.cache/bazel-repo"
          key: bazel-cache-${{ hashFiles('**/BUILD.bazel', '**/*.bzl', 'WORKSPACE') }}
          restore-keys: bazel-cache-

      - name: Configure Bazel version
        working-directory: ${{ matrix.folder }}
        # Overwrite the .bazelversion instead of using USE_BAZEL_VERSION so that Bazelisk
        # still bootstraps Aspect CLI from configuration in .bazeliskrc. Aspect CLI will
        # then use .bazelversion to determine which Bazel version to use
        run: echo "${{ matrix.bazelversion }}" > .bazelversion

      - name: Set bzlmod flag
        # Store the bzlmod flag that we add to the test command below
        # only when we're running bzlmod in our test matrix.
        id: set_bzlmod_flag
        if: matrix.bzlmodEnabled
        run: echo "bzlmod_flag=--config=bzlmod" >> $GITHUB_OUTPUT

      - name: bazel test //...
        env:
          # Bazelisk will download bazel to here, ensure it is cached between runs.
          XDG_CACHE_HOME: ~/.cache/bazel-repo
        working-directory: ${{ matrix.folder }}
        run: |
          bazel --bazelrc=${{ github.workspace }}/.github/workflows/ci.bazelrc --bazelrc=.bazelrc test ${{ steps.set_bzlmod_flag.outputs.bzlmod_flag }} //...