coverage.yaml

name: Coverage

# Manual-only coverage. The instrumented core + api builds are expensive, so
# they never run on push or PR open -- only when explicitly asked for:
#   * the Actions "Run workflow" button (workflow_dispatch), or
#   * a `/coverage` comment on a PR by a repo owner/member/collaborator.
# Both paths build core AND api coverage. The comment path posts the report
# back to the PR: unlike ci.yaml, an issue_comment run executes in the
# base-repo context with a write token, so it can comment directly -- no
# pr-comment.yaml delegation needed.
#
# NOTE: issue_comment triggers only fire for the workflow file on the default
# branch, so `/coverage` starts working once this file is merged to main.
on:
  workflow_dispatch:
  issue_comment:
    types: [created]

permissions:
  contents: read
  pull-requests: write

concurrency:
  group: coverage-${{ github.event.issue.number || github.ref }}
  cancel-in-progress: true

env:
  DOCKER_VOLUME: mx-build

jobs:
  coverage:
    runs-on: ubuntu-latest

    # Run on the manual button, or on a `/coverage` comment made on a PR (not a
    # plain issue) by someone with a write-ish association. Anything else -- a
    # comment on an issue, a different command, a drive-by commenter -- is
    # ignored.
    if: >-
      github.event_name == 'workflow_dispatch' ||
      (github.event.issue.pull_request &&
       startsWith(github.event.comment.body, '/coverage') &&
       contains(fromJSON('["OWNER", "MEMBER", "COLLABORATOR"]'), github.event.comment.author_association))

    steps:
      # Acknowledge the command so the requester knows it was accepted.
      - name: Acknowledge command
        if: github.event_name == 'issue_comment'
        uses: actions/github-script@v8
        with:
          script: |
            // Cosmetic ack only -- never fail the run if the reaction can't post.
            try {
              await github.rest.reactions.createForIssueComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: context.payload.comment.id,
                content: 'eyes',
              });
            } catch (e) {
              core.info(`Could not add reaction: ${e.message}`);
            }

      # workflow_dispatch checks out the triggering ref directly. The comment
      # path carries no PR ref in the event, so resolve the PR head SHA first.
      - name: Resolve PR head
        id: pr
        if: github.event_name == 'issue_comment'
        uses: actions/github-script@v8
        with:
          script: |
            const pr = await github.rest.pulls.get({
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: context.issue.number,
            });
            core.setOutput('sha', pr.data.head.sha);

      - uses: actions/checkout@v5
        with:
          ref: ${{ steps.pr.outputs.sha || github.sha }}

      # Same container-driver + runtime-token + bind-backed volume + ccache
      # setup as ci.yaml's Linux jobs so the instrumented builds reuse the warm
      # toolchain layer cache.
      - uses: docker/setup-buildx-action@v3
      - uses: crazy-max/ghaction-github-runtime@v3

      - name: Create bind-backed build volume
        run: |
          mkdir -p build/docker
          docker volume create --driver local \
            --opt type=none --opt o=bind \
            --opt device="$GITHUB_WORKSPACE/build/docker" mx-build

      - name: Cache ccache
        uses: actions/cache@v4
        with:
          path: build/docker/.ccache
          key: ccache-${{ runner.os }}-coverage-${{ github.sha }}
          restore-keys: ccache-${{ runner.os }}-coverage-

      - name: core coverage (corert + unit, instrumented)
        run: make core-coverage

      - name: api coverage (mxtest + round-trip, instrumented)
        run: make api-coverage

      # Turn gcovr's 3-line summaries (data/testOutput/coverage[/api]/summary.txt,
      # e.g. "lines: 52.1% (17624 out of 33846)") into Markdown tables for the
      # job summary and the PR comment.
      - name: Build coverage tables
        id: tables
        if: always()
        run: |
          make_table() {
            local file="$1"
            echo '| Metric | Coverage | Covered / Total |'
            echo '|---|---:|---:|'
            awk '/^(lines|functions|branches):/ {
              m=$1; sub(":","",m);
              c=$3; sub("[(]","",c);
              t=$6; sub("[)]","",t);
              M=toupper(substr(m,1,1)) substr(m,2);
              printf "| %s | %s | %s / %s |\n", M, $2, c, t
            }' "$file"
          }
          {
            echo '### Core-dev coverage `src/private/mx/core/`'
            echo ''
            make_table data/testOutput/coverage/summary.txt 2>/dev/null || echo '(core coverage not produced)'
            echo ''
            echo '### API coverage `src/private/mx/{api,impl,utility}/`'
            echo ''
            make_table data/testOutput/coverage/api/summary.txt 2>/dev/null || echo '(api coverage not produced)'
          } > tables.md
          cat tables.md >> "$GITHUB_STEP_SUMMARY"

      # Single self-contained page each, stored (compression-level 0). GitHub
      # delivers artifacts as a .zip -- there is no raw-file download -- so each
      # zip just holds one index.html to unzip and open.
      - name: Upload core HTML report
        id: upload-core
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: coverage-core-dev
          path: data/testOutput/coverage/index.html
          compression-level: 0

      - name: Upload api HTML report
        id: upload-api
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: coverage-api
          path: data/testOutput/coverage/api/index.html
          compression-level: 0

      # Post the report to the PR. issue_comment runs in the base-repo context
      # with a write token, so this comments directly. always() so a test
      # failure mid-build still reports whatever coverage was produced.
      - name: Post coverage comment
        if: always() && github.event_name == 'issue_comment'
        env:
          GH_TOKEN: ${{ github.token }}
          REPO: ${{ github.repository }}
          PR: ${{ github.event.issue.number }}
          SHA: ${{ steps.pr.outputs.sha }}
          CORE_URL: ${{ steps.upload-core.outputs.artifact-url }}
          API_URL: ${{ steps.upload-api.outputs.artifact-url }}
        run: |
          {
            echo '### Coverage report'
            echo ''
            cat tables.md
            echo ''
            echo "[Core HTML report]($CORE_URL) | [API HTML report]($API_URL)"
            echo ''
            echo "Commit \`$SHA\`."
          } > comment.md
          gh pr comment "$PR" --repo "$REPO" --body-file comment.md