feat: add comment-body output

[rzzf]

Releted: #2 (comment)

Write the results to outputs so downstream workflows can manage comments on their own. For example, the results can be uploaded as artifacts, and a workflow_run with write permissions can then post comments on PRs from forks.

Compressed Size Comment Body

name: Compressed Size Comment Body

on:
  pull_request:

jobs:
  size:
    runs-on: ubuntu-latest

    steps:
      - id: compressed-size
        uses: preactjs/compressed-size-action@v2
        with:
          repo-token: ${{ secrets.GITHUB_TOKEN }}

      - name: Save comment body
        env:
          COMMENT_BODY: ${{ steps.compressed-size.outputs.comment-body }}
        run: printf '%s\n' "$COMMENT_BODY" > compressed-size-comment.md

      - uses: actions/upload-artifact@v4
        with:
          name: compressed-size-comment
          path: compressed-size-comment.md

Compressed Size Comment Post

name: Compressed Size Comment Post

on:
  workflow_run:
    workflows: ['Compressed Size Comment Body']
    types: [completed]

jobs:
  comment:
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write

    steps:
      - uses: dawidd6/action-download-artifact@v21
        with:
          workflow: ${{ github.event.workflow.id }}
          run_id: ${{ github.event.workflow_run.id }}
          name: compressed-size-comment

      - id: comment
        run: |
          {
            echo 'body<<EOF'
            cat compressed-size-comment.md
            echo EOF
          } >> "$GITHUB_OUTPUT"

      - uses: actions-cool/maintain-one-comment@v3.3.0
        with:
          body: ${{ steps.comment.outputs.body }}
          body-include: '<!-- compressed-size-action -->'
          number: ${{ github.event.pull_request.number }}

[rschristian]

This is what I was concerned with by bumping the actions version:

---

Size Change: +132 kB (+325.89%) 🆘

Total Size: 173 kB

📦 View Changed

Filename	Size	Change
index.js	173 kB	+132 kB (+325.89%)	🆘

_{compressed-size-action}

---

Ideally want to avoid such a blow up, even for something that just runs as an action. At the very least, much harder to audit.

[rzzf]

This size increase is caused by the circular dependencies in @actions/core and its unfriendly tree-shaking behavior.

• Allow to transform programatical to ESM remove circular dependencies @actions/core actions/toolkit#981
• @actions/core support tree shaking when bundled in a GitHub Action. actions/toolkit#1436

I tested this locally with Github Local Action + Docker. If we don’t upgrade to 1.10.0 or later, we won’t be able to use outputs in the current CI environment unless we implement a simple setOutput ourselves. (Maybe my testing approach was incorrect? I’m not entirely sure either. 😅)

Test Workflow

name: Test comment-body

on:
  pull_request:
  push:

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

jobs:
  test:
    name: job
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v5
        with:
          fetch-depth: 0

      - id: compressed-size
        uses: ./
        with:
          repo-token: ${{ secrets.GITHUB_TOKEN }}
          base-ref: master
          pattern: index.js
          comment-key: output-smoke

      - name: Print comment-body output
        env:
          COMMENT_BODY: ${{ steps.compressed-size.outputs.comment-body }}
        run: |
          if [ -z "$COMMENT_BODY" ]; then
            echo "comment-body output is empty" >&2
            exit 1
          fi

          printf '%s\n' "$COMMENT_BODY"

If bundle size is a concern, I’d prefer to implement a lightweight setOutput ourselves. WDYT?

For example

export function setOutput(name, value) {
	const outputPath = process.env.GITHUB_OUTPUT;

	if (outputPath) {
		const delimiter = `ghadelimiter_${Date.now()}`;
		fs.appendFileSync(outputPath, `${name}<<${delimiter}${EOL}${value}${EOL}${delimiter}${EOL}`);
		return;
	}

	console.log(
		`::set-output name=${name}::${String(value).replace(/\n/g, '%0A').replace(/\r/g, '%0D')}`
	);
}

[rschristian]

Circular dependencies just result in (some) tools throwing a warning, it has no bearing whatsoever on final bundle size. Treeshaking is also less of an issue compared to plain bundle bloat that's been allowed to occur over there but 🤷

You can try pinning 1.10.0, tiny chance that's better than 1.11.1 (what you have now), but otherwise yes, I'd prefer we implement matching what you dug up earlier. I assume the code you've gathered above is an extracted version of what the lib otherwise uses?

[rzzf]

Circular dependencies just result in (some) tools throwing a warning, it has no bearing whatsoever on final bundle size. Treeshaking is also less of an issue compared to plain bundle bloat that's been allowed to occur over there but 🤷

It's nice to know this 👍

I assume the code you've gathered above is an extracted version of what the lib otherwise uses?

Yes, it is based on the implementation from core, with some simplified handling for name and value edge cases.

https://github.com/actions/toolkit/blob/8066c8132268398c77366dae936dac12c03d39ee/packages/core/src/core.ts#L217-L225

[rschristian]

Any progress will be reported here.

It's on my todo list, I'll get to it when I can. Thanks for bearing with me.