build-pr.yml

name: Comment on pull request

on:
    workflow_run:
        workflows: ["build"]
        types: [completed]

jobs:
    pr_comment:
        if: github.event.workflow_run.event == 'pull_request' && github.event.workflow_run.conclusion == 'success'
        runs-on: ubuntu-latest
        steps:
            - run: |
                  # Query the issue search API to get the PR associated with it
                  PR_RAW=$(curl 'https://api.github.com/search/issues?q=${{ github.event.workflow_run.head_commit.id }}')
                  # Get the event number from the search results, which will be the PR number
                  # Filter by PRs only in this repository, as a PR with an identical head commit may be made in another repository (e.g. a fork)
                  # Assume the 0th index in the array of found PRs is the correct one (it seems to usually be the latest one)
                  PR_NUM=$(echo $PR_RAW | jq '.items | map(select(.repository_url=="https://api.github.com/repos/${{ github.repository }}")) | .[0].number')
                  echo "PR_NUM=${PR_NUM}" >> ${GITHUB_ENV}
            - uses: actions/github-script@v7
              with:
                  # This snippet is public-domain, taken from
                  # https://github.com/oprypin/nightly.link/blob/master/.github/workflows/pr-comment.yml
                  # and modified to allow comments on external PRs
                  script: |
                      async function upsertComment(owner, repo, issue_number, purpose, body) {
                        const {data: comments} = await github.rest.issues.listComments(
                          {owner, repo, issue_number});
                        const marker = `<!-- bot: ${purpose} -->`;
                        body = marker + "\n" + body;
                        const existing = comments.filter((c) => c.body.includes(marker));
                        if (existing.length > 0) {
                          const last = existing[existing.length - 1];
                          core.info(`Updating comment ${last.id}`);
                          await github.rest.issues.updateComment({
                            owner, repo,
                            body,
                            comment_id: last.id,
                          });
                        } else {
                          core.info(`Creating a comment in issue / PR #${issue_number}`);
                          await github.rest.issues.createComment({issue_number, body, owner, repo});
                        }
                      }
                      const {owner, repo} = context.repo;
                      const run_id = '${{github.event.workflow_run.id}}';
                      const artifacts = await github.paginate(
                        github.rest.actions.listWorkflowRunArtifacts, {owner, repo, run_id});
                      if (!artifacts.length) {
                        return core.error(`No artifacts found`);
                      }
                      let body = `Download the artifacts for this pull request:\n`;
                      for (const art of artifacts) {
                        body += `\n* [${art.name}.zip](https://nightly.link/${owner}/${repo}/actions/artifacts/${art.id}.zip)`;
                      }
                      core.info("Review thread message body:");
                      core.info(body);
                      await upsertComment(owner, repo, ${{ env.PR_NUM }},
                        "nightly-link", body);