# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
# Exceptions. See /LICENSE for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

name: test

on:
  push:
    branches: [trunk]
    paths:
      # Conservatively run the tests. However, skip them if the only paths in
      # the pull request match files that we know don't impact the build.
      - '**'
      - '!**/*.md'
      - '!LICENSE'
      - '!CODEOWNERS'
      - '!.git*'
  pull_request:
    paths:
      # Conservatively run the tests. However, skip them if the only paths in
      # the pull request match files that we know don't impact the build.
      - '**'
      - '!**/*.md'
      - '!LICENSE'
      - '!CODEOWNERS'
      - '!.git*'

jobs:
  test:
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest]
        build_mode: [fastbuild, opt]
    runs-on: ${{ matrix.os }}
    steps:
      - name: Create environment variables
        run: |
          echo "BAZEL_OUTPUT_BASE_PATH=$HOME/.cache/bazel-output-base" >> $GITHUB_ENV
          echo "BAZEL=bazelisk --output_base=$HOME/.cache/bazel-output-base" >> $GITHUB_ENV

      - name: Checkout
        uses: actions/checkout@v2
        with:
          submodules: true

      # Setup Python and related tools.
      - uses: actions/setup-python@v2
        with:
          # Match the min version listed in docs/project/contribution_tools.md
          python-version: '3.6'

      # On macOS we need Go and to use it to install Bazelisk.
      - uses: actions/setup-go@v2
        if: matrix.os == 'macos-latest'
      - name: Install bazelisk
        if: matrix.os == 'macos-latest'
        run: |
          go get github.com/bazelbuild/bazelisk
          echo "$(go env GOPATH)/bin" >> $GITHUB_PATH

      # Print the various tool versions to help in debugging.
      - name: Print tool versions
        run: |
          bazelisk --version
          python --version

      # Make the date available to subsequent steps.
      - name: Get date
        id: date
        shell: bash
        run: |
          echo "::set-output name=date::$(/bin/date -u "+%Y%m%d")"

      # Preserve and restore the Bazel cache across builds.
      #
      # These cached entries are keyed on this file (which configures the
      # command and other inputs) as well as the date. Because Bazel is
      # hermetic, it doesn't matter if we get a "stale" entry here, but it makes
      # the cache less efficient. So we use the date to get a fresh baseline
      # cache once per day. We include this file so that changing the build
      # structure itself returns us to a clean state. We can also increment the
      # counter in this comment to forcibly rotate this hash in the event we get
      # a corrupted cache that breaks Bazel. This is a risk because we very
      # selectively prune directories out of the internals of the Bazel output
      # base to reduce the storage of the cache. At any point, this might break
      # invariants and require us to clear our caches. There is no way to
      # actually delete them and so instead we can simply bump the counter here.
      #
      # Current cache version: 2
      - name: Cache Bazel build data
        uses: actions/cache@v2
        with:
          # We exclude the install symlink so that Bazel reconnects to the
          # current installation. This helps repair any damage done by other
          # exclusions as well. Then we exclude the `external` tree because
          # those are all downloaded and rapidly rebuilt, so no benefit from
          # downloading them with the cached state.
          path: |
            ${{ env.BAZEL_OUTPUT_BASE_PATH }}
            !${{ env.BAZEL_OUTPUT_BASE_PATH }}/install
            !${{ env.BAZEL_OUTPUT_BASE_PATH }}/external
          key: |
            bazel-${{ matrix.os }}-${{ matrix.build_mode }}-${{ hashFiles('.github/workflows/tests.yaml')
            }}-${{ steps.date.outputs.date }}
          # When we get a cache miss, try finding the most recent previous day's
          # cache to start.
          restore-keys: |
            bazel-${{ matrix.os }}-${{ matrix.build_mode }}-${{ hashFiles('.github/workflows/tests.yaml')
            }}-

      # Print Bazel diagnostics to make debugging easier.
      - name: Print Bazel info
        run: |
          ${{ env.BAZEL }} info

      # Build all targets first to isolate build failures.
      - name: Build (${{ matrix.build_mode }})
        run: |
          ${{ env.BAZEL }} build -c ${{ matrix.build_mode }} --verbose_failures \
            --deleted_packages=migrate_cpp,migrate_cpp/cpp_refactoring \
            //...:all

      # Run all test targets.
      - name: Test (${{ matrix.build_mode }})
        run: |
          ${{ env.BAZEL }} test -c ${{ matrix.build_mode }} --test_output errors \
            --deleted_packages=migrate_cpp,migrate_cpp/cpp_refactoring \
            --verbose_failures //...:all

      # We manually shut down the Bazel server to make sure the cached files
      # don't interact with it.
      - name: Shutdown Bazel
        run: |
          ${{ env.BAZEL }} shutdown