MyGit

Minimal Git-like implementation in Swift. It supports repo initialization, staging, committing, status, and log, with Git-style object storage and optional compression. Built as a SwiftPM executable for macOS 10.15+.

Features

• mygit init sets up .mygit/, objects/, refs/, HEAD, and an empty index.
• mygit add <file> hashes content (SHA-1), stores blobs, and updates the staging index.
• mygit commit -m "msg" builds trees from the index, links parent commits, records author/committer/timestamps, writes commit objects, and updates refs/HEAD.
• mygit status shows modified/deleted/untracked files relative to the index.
• mygit log walks commit history from HEAD and prints commits.
• Global flags: --verbose for tracing actions, --compress to zlib-compress stored objects.

Requirements

• macOS 10.15+
• Swift toolchain with CryptoKit available (Command Line Tools or Xcode)

Building

swift build

Running

From the package root:

# Initialize a repository
.build/debug/MyGit init

# Stage a file
.build/debug/MyGit add path/to/file.txt

# Commit staged changes
.build/debug/MyGit commit -m "Initial commit"

# Inspect status
.build/debug/MyGit status

# View history
.build/debug/MyGit log

Global flags can precede the command:

.build/debug/MyGit --verbose --compress add file.txt

Author/Committer Info

Uses environment variables if set:

• MYGIT_AUTHOR_NAME, MYGIT_AUTHOR_EMAIL
• MYGIT_COMMITTER_NAME, MYGIT_COMMITTER_EMAIL Falls back to system user info when unset.

Notes

• Objects are stored Git-style under .mygit/objects/aa/bb.... Compression is optional.
• The index is a simple JSON mapping of path → blob hash (staged snapshot).
• HEAD defaults to refs/heads/main; commits update the branch ref or write directly to HEAD when detached.