coreutils/.github/workflows/SizeComment.yml

name: SizeComment

# spell-checker:ignore zizmor backquote

on:
  workflow_run:
    workflows: ["make"]
    types:
      - completed  # zizmor: ignore[dangerous-triggers]

permissions: {}
jobs:
  post-comment:
    permissions:
      actions: read  #  to list workflow runs artifacts
      pull-requests: write  #  to comment on pr

    runs-on: ubuntu-latest
    if: >
      github.event.workflow_run.event == 'pull_request'
    steps:
      - name: 'Download artifact'
        uses: actions/github-script@v9
        with:
          script: |
            // List all artifacts from the make workflow run
            var artifacts = await github.rest.actions.listWorkflowRunArtifacts({
              owner: context.repo.owner,
              repo: context.repo.repo,
              run_id: ${{ github.event.workflow_run.id }},
            });

            // Download the "size-comment" artifact, which contains a PR
            // number (NR) and result.txt produced by compare_size_results.py.
            var matchArtifact = artifacts.data.artifacts.filter((artifact) => {
              return artifact.name == "size-comment"
            })[0];
            if (!matchArtifact) {
              core.info("No size-comment artifact found; nothing to post.");
              return;
            }
            var download = await github.rest.actions.downloadArtifact({
              owner: context.repo.owner,
              repo: context.repo.repo,
              artifact_id: matchArtifact.id,
              archive_format: 'zip',
            });
            var fs = require('fs');
            fs.writeFileSync('${{ github.workspace }}/size-comment.zip', Buffer.from(download.data));
      - name: 'Unzip artifact'
        run: |
          if [ -f size-comment.zip ]; then
            unzip size-comment.zip
          fi

      - name: 'Comment on PR'
        uses: actions/github-script@v9
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const fs = require('fs');
            if (!fs.existsSync('./NR') || !fs.existsSync('./result.txt')) {
              core.info("No size comment payload to post.");
              return;
            }
            const issue_number = Number(fs.readFileSync('./NR'));
            if (!issue_number) {
              core.info("No PR number; skipping.");
              return;
            }
            const content = fs.readFileSync('./result.txt').toString();

            const marker = '<!-- size-comment-bot -->';
            const body = `${marker}\nBinary size comparison:\n\`\`\`\n${content}\`\`\``;

            const { data: comments } = await github.rest.issues.listComments({
              ...context.repo,
              issue_number
            });

            const existing = comments.find(c =>
              c.user.login === 'github-actions[bot]' &&
              c.body.includes(marker)
            );

            if (existing) {
              await github.rest.issues.updateComment({
                ...context.repo,
                comment_id: existing.id,
                body
              });
            } else {
              // Only comment when there is something meaningful to say.
              // compare_size_results.py only writes the file when there is a
              // significant change, so an empty/short body is treated as
              // "nothing to report".
              if (content.trim().length == 0) {
                return;
              }
              await github.rest.issues.createComment({
                ...context.repo,
                issue_number,
                body
              });
            }