MergeGuard

Detect cross-PR conflicts before they reach your merge queue.

MergeGuard analyzes open pull requests and finds conflicts between them — hard overlaps, interface breaks, behavioral incompatibilities, duplications, transitive dependencies, and regressions — while you're still developing, not at merge time.

The Problem

Traditional CI checks a single PR against the base branch. It can't see that two PRs are about to break each other. Merge queues (Mergify, Trunk, Aviator) catch this at merge time — but by then you've already done the work.

MergeGuard catches it during development.

Quick Start

pip install py-mergeguard

cd your-repo
export GITHUB_TOKEN=ghp_...
mergeguard analyze --pr 42

That's it. Auto-detects platform and repo from your git remote.

What It Detects

GitHub Action

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

jobs:
  analyze:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: Vansh2795/mergeguard@v1
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}

How It Compares

Platforms

CLI Commands

mergeguard analyze --pr 42          # Analyze a PR for cross-PR conflicts
mergeguard map                      # Collision map of all open PRs
mergeguard suggest-order            # Optimal merge sequence
mergeguard watch                    # Continuous monitoring
mergeguard serve                    # Webhook server for real-time detection
mergeguard init                     # Interactive setup wizard

Configuration

# .mergeguard.yml
risk_threshold: 50
max_open_prs: 30
ignored_paths:
  - "*.lock"
  - "package-lock.json"

See Configuration Guide for all options.

Benchmarks

Tested against real open-source repos. Transitive accuracy improvements reduced false positives by 59-82% on FastAPI. See Benchmark Results.

Documentation

• Getting Started
• How It Works
• CI Setup
• Configuration
• Architecture
• Benchmark Results
• Contributing
• Changelog

Also Included

MergeGuard ships with additional features for enterprise workflows:

• Policy engine — declarative conditions-and-actions for merge automation
• DORA metrics — conflict resolution time tracking
• Blast radius visualization — interactive D3.js dependency graph
• CODEOWNERS routing — team-aware Slack/Teams notifications
• Merge queue integration — commit status checks with priority labels
• Stacked PR support — Graphite, branch chains, label-based detection
• MCP server — AI agent integration (check_conflicts, get_risk_score, suggest_merge_order)

See docs/ for details on each feature.

Development

git clone https://github.com/Vansh2795/mergeguard.git
cd mergeguard
uv sync --dev
uv run pytest
uv run ruff check src/ tests/
uv run mypy src/

License

MIT — see LICENSE.