forked-pr-coverage.yml

name: Post Coverage Comment

# This workflow handles posting coverage comments for FORKED PRs.
#
# Why a separate workflow?
# - Forked PRs have restricted GITHUB_TOKEN permissions for security
# - They cannot write comments directly to the base repository's PRs
# - workflow_run triggers run in the BASE repository context with full permissions
# - This allows us to safely post comments on forked PRs
#
# How it works:
# 1. PR Code Coverage workflow uploads coverage data as an artifact (forked PRs only)
# 2. This workflow triggers when PR Code Coverage completes successfully
# 3. Downloads the artifact and posts the comment with full write permissions
#
# Same-repo PRs post comments directly in pr-code-coverage.yml (faster)
# Forked PRs use this workflow (required for permissions)

on:
  workflow_run:
    workflows: ["PR Code Coverage"]
    types:
      - completed

jobs:
  post-comment:
    runs-on: ubuntu-latest
    if: >
      github.event.workflow_run.event == 'pull_request' &&
      github.event.workflow_run.conclusion == 'success'
    permissions:
      pull-requests: write
      contents: read
    
    steps:
      - name: Checkout repo
        uses: actions/checkout@v4

      - name: Download coverage data
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          # Download artifact with error handling for non-existent artifacts
          if ! gh run download ${{ github.event.workflow_run.id }} \
            --repo ${{ github.repository }} \
            --name coverage-comment-data 2>&1; then
            echo "⚠️ No coverage-comment-data artifact found"
            echo "This is expected for same-repo PRs (they post comments directly)"
            echo "Exiting gracefully..."
            exit 0
          fi
          
          # Verify artifact was downloaded
          if [[ ! -f pr-info.json ]]; then
            echo "⚠️ Artifact downloaded but pr-info.json not found"
            echo "This may indicate an issue with artifact upload"
            exit 1
          fi

      - name: Read coverage data
        id: coverage
        run: |
          if [[ ! -f pr-info.json ]]; then
            echo "❌ pr-info.json not found"
            exit 1
          fi
          
          cat pr-info.json
          
          # Extract values from JSON with proper quoting
          PR_NUMBER="$(jq -r '.pr_number' pr-info.json)"
          COVERAGE_PCT="$(jq -r '.coverage_percentage' pr-info.json)"
          COVERED_LINES="$(jq -r '.covered_lines' pr-info.json)"
          TOTAL_LINES="$(jq -r '.total_lines' pr-info.json)"
          PATCH_PCT="$(jq -r '.patch_coverage_pct' pr-info.json)"
          LOW_COV_FILES="$(jq -r '.low_coverage_files' pr-info.json)"
          PATCH_SUMMARY="$(jq -r '.patch_coverage_summary' pr-info.json)"
          ADO_URL="$(jq -r '.ado_url' pr-info.json)"
          
          # Export to env for next step (single-line values)
          echo "PR_NUMBER=${PR_NUMBER}" >> $GITHUB_ENV
          echo "COVERAGE_PERCENTAGE=${COVERAGE_PCT}" >> $GITHUB_ENV
          echo "COVERED_LINES=${COVERED_LINES}" >> $GITHUB_ENV
          echo "TOTAL_LINES=${TOTAL_LINES}" >> $GITHUB_ENV
          echo "PATCH_COVERAGE_PCT=${PATCH_PCT}" >> $GITHUB_ENV
          echo "ADO_URL=${ADO_URL}" >> $GITHUB_ENV
          
          # Handle multiline values with proper quoting
          {
            echo "LOW_COVERAGE_FILES<<EOF"
            echo "$LOW_COV_FILES"
            echo "EOF"
          } >> $GITHUB_ENV
          
          {
            echo "PATCH_COVERAGE_SUMMARY<<EOF"
            echo "$PATCH_SUMMARY"
            echo "EOF"
          } >> $GITHUB_ENV

      - name: Comment coverage summary on PR
        uses: ./.github/actions/post-coverage-comment
        with:
          pr_number: ${{ env.PR_NUMBER }}
          coverage_percentage: ${{ env.COVERAGE_PERCENTAGE }}
          covered_lines: ${{ env.COVERED_LINES }}
          total_lines: ${{ env.TOTAL_LINES }}
          patch_coverage_pct: ${{ env.PATCH_COVERAGE_PCT }}
          low_coverage_files: ${{ env.LOW_COVERAGE_FILES }}
          patch_coverage_summary: ${{ env.PATCH_COVERAGE_SUMMARY }}
          ado_url: ${{ env.ADO_URL }}