Fix lighthouse_comment workflow to handle workflow_run event context

[Copilot]

The lighthouse_comment.yml workflow fails to post PR comments because it accesses github.event.pull_request.number, which doesn't exist in workflow_run trigger contexts.

Changes

Artifact download

• Added run-id: ${{ github.event.workflow_run.id }} to download artifacts from the triggering workflow run

PR number extraction

• Extract from github.event.workflow_run.pull_requests[0].number with null/empty validation
• Fail early with descriptive error if extraction fails

Execution control

• Added if: github.event.workflow_run.conclusion == 'success' to skip commenting on failed runs

- name: Extract PR number
  id: pr
  run: |
    PR_NUMBER=$(jq -r '.workflow_run.pull_requests[0].number' <<< '${{ toJSON(github.event) }}')
    if [ -z "$PR_NUMBER" ] || [ "$PR_NUMBER" = "null" ]; then
      echo "❌ Error: Could not extract PR number from workflow run event"
      exit 1
    fi
    echo "number=$PR_NUMBER" >> $GITHUB_OUTPUT

- name: Post Lighthouse comment
  uses: peter-evans/create-or-update-comment@v4
  with:
    issue-number: ${{ steps.pr.outputs.number }}
    body-path: lighthouse-comment.md

Original prompt

Hey copilot, currently there is a problem in the lighthouse github actions, there are two actions are there run and comment, the comment is working but the run is not working, please help me to fix the issues

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[Copilot]

Pull request overview

This PR fixes the lighthouse_comment.yml workflow to correctly handle workflow_run event contexts. The workflow previously failed because it tried to access github.event.pull_request.number, which doesn't exist when triggered by a workflow_run event.

Changes:

• Added execution control to only run on successful workflow runs
• Configured artifact download to fetch from the triggering workflow run using run-id
• Implemented PR number extraction from workflow_run.pull_requests[0].number with proper validation
• Updated comment posting to use the dynamically extracted PR number

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[dhananjay6561]

Hey @copilot-swe-agent 👋 — thanks so much for contributing to the project, really appreciate it!

Your PR looks great and has been marked for merging. Here's a quick note from the reviewer:

Correctly extracts PR number from workflow_run event context.

We'll get this merged in soon. Keep the great work coming! 🚀

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 2 comments.

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[Copilot]

actions/download-artifact@v4 with run-id calls the Actions Artifacts API; with the workflow-level permissions: block present, the default GITHUB_TOKEN no longer has implicit actions: read. This will typically fail with Resource not accessible by integration. Add actions: read (or remove the explicit permissions block and set least-privilege explicitly including actions: read) so the artifact download can succeed.

[Copilot]

The failure message for missing PR number is descriptive but doesn’t suggest a next step. Consider expanding it to include likely causes (e.g., the triggering run wasn’t associated with a PR, or workflow_run.pull_requests was empty) and what to check (triggering workflow event type / repository settings) to speed up triage.

Suggested change

echo "❌ Error: Could not extract PR number from workflow run event"

echo "❌ Error: Could not extract a PR number from the workflow_run event. This usually means the triggering workflow run was not associated with a pull request or workflow_run.pull_requests was empty. Next, check that the upstream \"Lighthouse – Run\" workflow was triggered by a pull_request-related event and confirm the repository/workflow settings allow PR context to be included in workflow_run payloads."