lesson-gate.yml

name: Lesson Quality Gate

# Structural gate (issue #889): blocks PRs whose NEW/CHANGED lessons fail the
# quality checks (required frontmatter fields, min content length, duplicate
# titles, allowed domain, tag format). Runs only on lessons/ changes.
on:
  pull_request:
    paths:
      - 'lessons/**'
      - 'scripts/lesson_gate.py'
      - 'tests/test_lesson_gate.py'

permissions:
  contents: read
  pull-requests: write

jobs:
  gate:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v7
        with:
          fetch-depth: 0

      - name: Setup Python
        uses: actions/setup-python@v5
        with:
          python-version: '3.12'

      - name: Get changed lesson files
        id: changed
        uses: tj-actions/changed-files@v47.0.6
        with:
          files: |
            lessons/**/*.md

      - name: Run lesson quality gate
        if: steps.changed.outputs.any_changed == 'true'
        id: gate
        run: |
          FILES="${{ steps.changed.outputs.all_changed_files }}"
          # Convert space-separated list to args (paths have no spaces in this repo)
          python3 scripts/lesson_gate.py $FILES > gate_report.txt 2>&1
          GATE_EXIT=$?
          cat gate_report.txt
          echo "gate_exit=$GATE_EXIT" >> "$GITHUB_OUTPUT"
          if [ "$GATE_EXIT" -ne 0 ]; then
            echo "❌ Lesson quality gate FAILED — see report below."
            exit 1
          fi

      - name: Run unit tests for the gate
        if: steps.changed.outputs.any_changed == 'true'
        run: |
          pip install -q pytest
          python3 -m pytest tests/test_lesson_gate.py -q

      - name: Comment gate result on PR
        if: steps.changed.outputs.any_changed == 'true'
        uses: actions/github-script@v9
        with:
          script: |
            const fs = require('fs');
            let report = '✅ **Lesson Quality Gate passed.**';
            let icon = '✅';
            try {
              const gateReport = fs.readFileSync('gate_report.txt', 'utf8');
              if (gateReport.includes('FAIL')) {
                icon = '❌';
                report = '❌ **Lesson Quality Gate failed.** Check the report below.';
              }
              report += '\n\n```\n' + gateReport + '\n```';
            } catch (e) {}
            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: report,
            });