links.yml

name: Link check

# The repository carries ~270 external links, many of them years old. This runs
# weekly rather than per-push: link rot is not caused by a commit, and failing a
# pull request because a third-party site is briefly down would be noise.

on:
  schedule:
    - cron: "0 6 * * 1"      # Mondays, 06:00 UTC
  workflow_dispatch:

permissions:
  contents: read
  issues: write

jobs:
  check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - uses: actions/setup-python@v5
        with:
          python-version: "3.12"

      # scripts/check_links.py is standard library only, so nothing to install.
      # It reports MOVED as well as DEAD: three MDN links in this repository once
      # returned HTTP 200 through a redirect while their canonical URL had
      # changed underneath, which a 404-only checker passes in silence.
      - name: Check links
        id: links
        run: |
          set +e
          python scripts/check_links.py --json link-report.json | tee link-output.txt
          echo "exit_code=$?" >> "$GITHUB_OUTPUT"
          set -e

      - name: Summary
        if: always()
        run: |
          {
            echo '## Link check'
            echo
            echo '```'
            tail -40 link-output.txt
            echo '```'
          } >> "$GITHUB_STEP_SUMMARY"

      - uses: actions/upload-artifact@v4
        if: always()
        with:
          name: link-report
          path: |
            link-report.json
            link-output.txt

      - name: Fail if any link is dead
        if: steps.links.outputs.exit_code != '0'
        run: |
          echo "Dead links found -- see the job summary and the link-report artifact."
          exit 1