git-reunify

Safe repository reunification for diverged codebases

The Problem

Developers fork, branch, or split repos. Time passes. They want to merge back together.

Traditional git merge often fails because:

• Unrelated histories

• Conflicting directory structures

• Risk of losing one developer’s work

• No clear audit trail of what came from where

The Solution

git-reunify safely merges diverged repositories:

git-reunify \
  --primary repo-a \
  --absorb repo-b \
  --strategy subdirectory \
  --backup-tag "pre-merge-$(date +%Y%m%d)"

Features

• Safety first: Creates tagged backups before any operation

• History preservation: All commits from both repos survive

• Conflict detection: Identifies overlapping files before merge

• Audit trail: Generates merge report showing what went where

• Rollback support: Easy undo if something goes wrong

Strategies

Strategy	Use Case	Preserves Structure
subdirectory	Different components (frontend/backend)	Yes - puts absorbed repo in subdir
overlay	Same project, parallel development	Merges at root, renames conflicts
timestamp	Keep both versions, decide later	Suffixes files with source repo name

Installation

# Homebrew (macOS/Linux)
brew install hyperpolymath/tap/git-reunify

# Cargo (Rust)
cargo install git-reunify

# From source
just install

Quick Start

# 1. Analyze what would happen
git-reunify analyze --primary ./main-repo --absorb ./diverged-repo

# 2. Preview the merge (dry run)
git-reunify merge --primary ./main-repo --absorb ./diverged-repo --dry-run

# 3. Execute the merge
git-reunify merge --primary ./main-repo --absorb ./diverged-repo

License

MIT OR Palimpsest-0.8