PR Size Checker

A reusable GitHub Action that automatically checks Pull Request size and adds appropriate labels.

Features

• Automatically calculates total lines changed (additions + deletions)
• Adds size-based labels: small, medium, large, extra-large
• Automatically creates labels if they don't exist in the repository
• Removes old labels when size changes
• Comments on large PRs suggesting split (optional)
• Configurable with custom thresholds

Usage

Basic Setup

Create a .github/workflows/pr-size-check.yml file in your repository:

name: PR Size Check

on:
  pull_request:
    types: [opened, synchronize, reopened]

jobs:
  check-pr-size:
    runs-on: ubuntu-latest
    name: Check PR Size
    steps:
      - name: Check PR Size
        uses: automationDojo/github-custom-action-examples@main
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}

Advanced Configuration

name: PR Size Check

on:
  pull_request:
    types: [opened, synchronize, reopened]

jobs:
  check-pr-size:
    runs-on: ubuntu-latest
    name: Check PR Size
    steps:
      - name: Check PR Size
        uses: automationDojo/github-custom-action-examples@main
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          small-threshold: 100      # PRs up to 100 lines = small
          medium-threshold: 300     # PRs up to 300 lines = medium
          large-threshold: 600      # PRs up to 600 lines = large
          comment-on-large: true    # Comment on large PRs

Inputs

Input	Description	Required	Default
github-token	GitHub token for API calls	Yes	-
small-threshold	Maximum lines changed for a small PR	No	100
medium-threshold	Maximum lines changed for a medium PR	No	300
large-threshold	Maximum lines changed for a large PR	No	600
comment-on-large	Whether to comment on large PRs	No	true

Outputs

Output	Description
size-label	Label applied to the PR (small, medium, large, extra-large)
lines-changed	Total number of lines changed

Example Usage with Outputs

- name: Check PR Size
  id: pr-size
  uses: automationDojo/github-custom-action-examples@main
  with:
    github-token: ${{ secrets.GITHUB_TOKEN }}

- name: Display PR Size
  run: |
    echo "PR Size: ${{ steps.pr-size.outputs.size-label }}"
    echo "Lines Changed: ${{ steps.pr-size.outputs.lines-changed }}"

Labels Created

The action automatically creates the following labels:

Label	Color	Description
small	Green	Small PRs, easy to review
medium	Yellow	Medium-sized PRs
large	Orange	Large PRs, consider splitting
extra-large	Red	Very large PRs, splitting recommended

How It Works

1. The action is triggered on pull request events
2. Calculates total lines changed (additions + deletions)
3. Determines size based on configured thresholds
4. Removes old size labels
5. Adds the appropriate new label
6. If the PR is large or extra-large, adds a comment suggesting split

Local Development

Prerequisites

• Node.js 20 or higher
• npm

Setup

npm install
npm run build

Building

The action uses @vercel/ncc to compile the code and dependencies into a single file. This eliminates the need to commit node_modules.

npm run build

This creates a dist/index.js file that includes all dependencies bundled together.

File Structure

github-custom-action-examples/
├── action.yml          # Action metadata (points to dist/index.js)
├── index.js           # Main logic (source)
├── dist/
│   └── index.js       # Bundled code with dependencies (commit this!)
├── package.json       # Dependencies
├── README.md          # Documentation
└── .github/
    └── workflows/
        ├── release.yml                # Semantic Release workflow
        ├── pr-size-check.yml          # Local usage example
        └── pr-size-check-external.yml # External usage example

Releases and Versioning

This project uses Semantic Release for automated versioning and releases.

Commit Message Format

Follow the Conventional Commits specification:

• feat: - A new feature (triggers minor version bump)
• fix: - A bug fix (triggers patch version bump)
• docs: - Documentation changes
• chore: - Maintenance tasks
• BREAKING CHANGE: - Breaking changes (triggers major version bump)

Examples:

feat: add support for custom label colors
fix: resolve issue with label removal
docs: update README with new examples
chore: update dependencies

How It Works

1. Push commits to main branch using conventional commit format
2. Semantic Release analyzes commits and determines version bump
3. Automatically generates CHANGELOG.md
4. Creates a GitHub release with release notes
5. Updates version in package.json

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a branch for your feature
3. Commit your changes using conventional commit format
4. Open a Pull Request

License

MIT

Author

AutomationDojo

Useful Links

• GitHub Actions Documentation
• Creating a JavaScript Action