Modern VCS (mvcs)

A modern version control system built in Rust, inspired by Git and Jujutsu (jj).

Features

Core VCS Features

• Repository Management: Initialize, clone, and manage repositories
• Content-Addressable Storage: Efficient object storage with deduplication
• Staging Area: Track changes and prepare commits
• Commit System: Create and manage commits with metadata
• Branch Management: Create, switch, and merge branches
• Diff Engine: Compare files and generate patches
• Three-Way Merging: Automatic conflict resolution with manual fallback
• Remote Operations: Push, pull, and sync with remote repositories

Modern Features (inspired by jj)

• Operation Log: Track all repository operations with undo capability
• Change IDs: Immutable identifiers for changes
• Working Copy as Commit: Treat working directory as a commit
• Describe Command: Update commit messages after creation
• New Command: Create new changes based on existing ones

Production-Ready Features

• Comprehensive Error Handling: Detailed error messages and recovery
• Cross-Platform Support: Works on Windows, macOS, and Linux
• Efficient Storage: Compressed object storage
• Conflict Resolution: Advanced merge conflict handling
• Configuration Management: User and repository settings
• CLI Interface: Full-featured command-line interface

Installation

cargo install --path .

Quick Start

Initialize a repository

mvcs init

Configure user (global)

mvcs config --global user.name "Your Name"
mvcs config --global user.email "[email protected]"

Add files and commit

mvcs add .
mvcs commit -m "Initial commit"

Create and switch branches

mvcs branch feature-branch
mvcs checkout feature-branch

View status and history

mvcs status
mvcs log
mvcs diff

Work with remotes

mvcs remote add origin https://example.com/repo.git
mvcs push origin main
mvcs pull origin main

Commands

Basic Commands

• mvcs init [directory] - Initialize a new repository
• mvcs clone <url> [directory] - Clone a repository
• mvcs add <files> - Add files to staging area
• mvcs commit -m "message" - Create a commit
• mvcs status - Show working tree status
• mvcs log - Show commit history
• mvcs diff - Show changes

Branch Commands

• mvcs branch - List branches
• mvcs branch <name> - Create a branch
• mvcs branch -d <name> - Delete a branch
• mvcs checkout <branch> - Switch branches
• mvcs checkout -b <name> - Create and switch to branch

Merge Commands

• mvcs merge <branch> - Merge a branch
• mvcs merge --no-ff <branch> - Force merge commit

Remote Commands

• mvcs remote add <name> <url> - Add a remote
• mvcs remote list - List remotes
• mvcs push <remote> <branch> - Push to remote
• mvcs pull <remote> <branch> - Pull from remote

Advanced Commands

• mvcs show <object> - Show object details
• mvcs reset [--hard|--soft] [commit] - Reset to commit
• mvcs describe -m "message" [change] - Update commit message
• mvcs new [base] - Create new change
• mvcs oplog - Show operation log

Architecture

Object Storage

• Blobs: File content
• Trees: Directory structure
• Commits: Snapshots with metadata
• Compressed Storage: All objects are compressed with zlib

Index/Staging

• Staging Area: Prepare commits incrementally
• Conflict Resolution: Handle merge conflicts with stages
• File Status Tracking: Track added, modified, deleted files

Repository Structure

.mvcs/
├── objects/          # Content-addressable object storage
├── refs/
│   ├── heads/        # Branch references
│   └── remotes/      # Remote branch references
├── index             # Staging area
├── HEAD              # Current branch/commit reference
├── config            # Repository configuration
└── oplog             # Operation log

Modern Features

Operation Log

Every operation is logged with:

• Operation ID and timestamp
• User information
• Before/after commit hashes
• Operation description

Change IDs

Each commit has:

• Content hash (traditional)
• Change ID (immutable, survives rebases)

Working Copy as Commit

• Working directory is treated as a commit
• Enables advanced workflows
• Simplifies conflict resolution

Development

Building

cargo build --release

Testing

cargo test

Running

cargo run -- <command>

Comparison with Git

Feature	Git	mvcs
Object Storage	✓	✓
Branches	✓	✓
Merging	✓	✓ (improved)
Remotes	✓	✓
Operation Log	✗	✓
Change IDs	✗	✓
Working Copy Commits	✗	✓
Conflict Resolution	Basic	Advanced

Comparison with Jujutsu

Feature	jj	mvcs
Change IDs	✓	✓
Operation Log	✓	✓
Working Copy Commits	✓	✓
Git Compatibility	✓	Partial
Conflict Resolution	✓	✓
Performance	High	High

License

MIT License - see LICENSE file for details.

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests
5. Submit a pull request

Roadmap

• Git interoperability
• Advanced merge algorithms
• Distributed operation log
• Web interface
• IDE integrations
• Performance optimizations
• Advanced conflict resolution UI