test-impact-plan-comment.yml

name: test-impact-plan-comment

on:
  workflow_run:
    workflows: ["test-impact-plan"]
    types: [completed]

permissions:
  contents: read
  issues: write
  pull-requests: write

concurrency:
  group: test-impact-plan-comment-${{ github.event.workflow_run.head_repository.full_name }}-${{ github.event.workflow_run.head_branch }}
  cancel-in-progress: true

jobs:
  comment:
    if: github.event.workflow_run.event == 'pull_request' && github.event.workflow_run.conclusion == 'success'
    runs-on: ubuntu-24.04-arm
    timeout-minutes: 5
    steps:
      - name: Checkout trusted default branch
        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
        with:
          ref: ${{ github.event.repository.default_branch }}
          fetch-depth: 1
          persist-credentials: false

      - name: Resolve pull request context
        id: context
        env:
          GH_TOKEN: ${{ github.token }}
          REPOSITORY: ${{ github.repository }}
          RUN_HEAD_SHA: ${{ github.event.workflow_run.head_sha }}
          TARGET_BRANCH: ${{ github.event.repository.default_branch }}
        run: |
          set -euo pipefail
          pr_count="$(jq -r '.workflow_run.pull_requests | length' "$GITHUB_EVENT_PATH")"
          if [ "$pr_count" != "1" ]; then
            echo "Expected one pull request context, found $pr_count."
            echo "current=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          pr_number="$(jq -r '.workflow_run.pull_requests[0].number // empty' "$GITHUB_EVENT_PATH")"
          if [ -z "$pr_number" ]; then
            echo "No pull request context found for workflow run."
            echo "current=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          pr_json=/tmp/test-impact-pr.json
          gh api "repos/$REPOSITORY/pulls/$pr_number" > "$pr_json"
          head_sha="$(jq -r '.head.sha' "$pr_json")"
          state="$(jq -r '.state' "$pr_json")"
          base_repo="$(jq -r '.base.repo.full_name' "$pr_json")"
          base_ref="$(jq -r '.base.ref' "$pr_json")"
          changed_files="$(jq -r '.changed_files' "$pr_json")"

          if [ "$state" != "open" ]; then
            echo "Skipping PR #$pr_number because it is $state."
            echo "current=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          if [ "$base_repo" != "$REPOSITORY" ] || [ "$base_ref" != "$TARGET_BRANCH" ]; then
            echo "Skipping PR #$pr_number targeting $base_repo:$base_ref."
            echo "current=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          if [ "$head_sha" != "$RUN_HEAD_SHA" ]; then
            echo "Skipping stale workflow run for $RUN_HEAD_SHA; current PR head is $head_sha."
            echo "current=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          echo "current=true" >> "$GITHUB_OUTPUT"
          echo "pr_number=$pr_number" >> "$GITHUB_OUTPUT"
          echo "changed_files=$changed_files" >> "$GITHUB_OUTPUT"

      - name: Generate test impact plan
        if: steps.context.outputs.current == 'true'
        env:
          GH_TOKEN: ${{ github.token }}
          PR_NUMBER: ${{ steps.context.outputs.pr_number }}
          REPOSITORY: ${{ github.repository }}
          CHANGED_FILES: ${{ steps.context.outputs.changed_files }}
        run: |
          set -euo pipefail
          gh api "repos/$REPOSITORY/pulls/$PR_NUMBER/files?per_page=100" \
            --paginate \
            --slurp \
            > /tmp/test-impact-pr-files.json

          python3 scripts/test_impact_plan.py \
            --github-pr-files-json /tmp/test-impact-pr-files.json \
            --expected-file-count "$CHANGED_FILES" \
            --markdown-output /tmp/test-impact-plan.md \
            --json-output /tmp/test-impact-plan.json

          cat /tmp/test-impact-plan.md >> "$GITHUB_STEP_SUMMARY"

      - name: Comment on pull request
        if: steps.context.outputs.current == 'true'
        env:
          GH_TOKEN: ${{ github.token }}
          PR_NUMBER: ${{ steps.context.outputs.pr_number }}
          REPOSITORY: ${{ github.repository }}
        run: |
          set -euo pipefail
          marker="<!-- test-impact-plan -->"
          body_file=/tmp/test-impact-plan-comment.md
          {
            echo "$marker"
            cat /tmp/test-impact-plan.md
          } > "$body_file"

          existing_id="$(
            gh api "repos/$REPOSITORY/issues/$PR_NUMBER/comments" --paginate \
              --jq '.[] | select(.user.login == "github-actions[bot]" and (.body | startswith("<!-- test-impact-plan -->"))) | .id' \
              | tail -n 1
          )"

          if [ -n "$existing_id" ]; then
            gh api "repos/$REPOSITORY/issues/comments/$existing_id" \
              -X PATCH \
              -F "body=@$body_file" >/dev/null
          else
            gh api "repos/$REPOSITORY/issues/$PR_NUMBER/comments" \
              -F "body=@$body_file" >/dev/null
          fi