🚬 Big Diff Energy Action

A GitHub Action that automatically comments on PRs with large diffs (1000+ additions by default), showing the change statistics with a humorous touch.

Why?

Large PRs are harder to review and more prone to issues slipping through. This action gently reminds contributors to consider breaking up massive changes into smaller, more reviewable chunks.

Features

• 🔍 Automatically detects PRs with large diffs
• 📊 Shows addition and deletion statistics in a clean two-column layout with color indicators
• 🔄 Dynamically updates comment numbers as PR changes
• 🧹 Auto-deletes comment when PR is cleaned up below threshold (rewards good behavior!)
• ⚙️ Configurable threshold for what counts as "large" (default: 1000 additions)
• 🎨 Includes a fun image to keep things light-hearted

Usage

Add this action to your repository's workflow:

name: Big Diff Check
on:
  pull_request:
    types: [opened, synchronize, reopened]

permissions:
  pull-requests: write
  contents: read

jobs:
  check-pr-size:
    runs-on: ubuntu-latest
    steps:
      - name: Check for big diffs
        uses: lukasjuhas/big-diff-energy-action@v1
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          threshold: 1000  # Optional: defaults to 1000

Inputs

Input	Description	Required	Default
github-token	GitHub token for posting comments	Yes	N/A
threshold	Minimum number of additions to trigger the comment	No	1000
title	Custom title for the comment	No	This PR has some **big diff energy**:
message	Custom message to display below the stats	No	That's a lot of changes! Consider breaking this into smaller PRs for easier review.
image-url	Custom image URL for the comment	No	https://raw.githubusercontent.com/lukasjuhas/big-diff-energy-action/main/assets/matthew-smoking.jpeg

Permissions

This action requires the following permissions:

permissions:
  pull-requests: write  # To post comments
  contents: read        # To read PR files

Example Comment

When triggered, the action posts a comment like this:

The comment uses a two-column layout with Matthew smoking on the left and stats on the right, with color indicators (🟢 for additions, 🔴 for deletions).

How It Works

1. Triggered on PR open, synchronize, or reopen events
2. Fetches all files changed in the PR
3. Calculates total additions and deletions
4. Smart comment management:
   • If above threshold and no comment exists: Posts new comment
   • If above threshold and comment exists: Updates comment with new numbers
   • If below threshold and comment exists: Deletes comment (rewards cleanup!)

Customization

Different Threshold

Want to be stricter or more lenient? Adjust the threshold:

- uses: lukasjuhas/big-diff-energy-action@v1
  with:
    github-token: ${{ secrets.GITHUB_TOKEN }}
    threshold: 500  # Trigger on 500+ additions

Custom Title and Message

Personalize the comment to match your team's style:

- uses: lukasjuhas/big-diff-energy-action@v1
  with:
    github-token: ${{ secrets.GITHUB_TOKEN }}
    title: "🐘 This PR is quite large!"
    message: "Please consider splitting this into multiple smaller PRs. Our team prefers PRs under 500 lines for better review quality."

Custom Image

Use your own image URL:

- uses: lukasjuhas/big-diff-energy-action@v1
  with:
    github-token: ${{ secrets.GITHUB_TOKEN }}
    image-url: "https://example.com/your-custom-image.png"

Full Customization Example

Combine all options for complete control:

- uses: lukasjuhas/big-diff-energy-action@v1
  with:
    github-token: ${{ secrets.GITHUB_TOKEN }}
    threshold: 800
    title: "⚠️ Large PR detected"
    message: "This PR exceeds our recommended size. Please review our [contribution guidelines](https://example.com/guidelines) for best practices."
    image-url: "https://example.com/custom-warning.png"

Workflow Triggers

You can customize when the action runs:

on:
  pull_request:
    types: [opened]  # Only on first open, not on updates

Development

Local Setup

# Clone the repo
git clone https://github.com/lukasjuhas/big-diff-energy-action.git
cd big-diff-energy-action

# Install dependencies
npm install

# Make your changes to index.js

Testing

To test this action in your own repository:

1. Reference it using a branch or commit SHA:

- uses: lukasjuhas/big-diff-energy-action@main

1. Create a PR with 1000+ line additions to trigger the comment

Contributing

Contributions are welcome! Feel free to:

• Open issues for bugs or feature requests
• Submit PRs with improvements
• Share feedback on the action

License

MIT © Lukas Juhas

Credits

Inspired by the eternal struggle of reviewing massive PRs. 🙏