Lecture Notes: Scott Chacon's Talk on Git

Introduction

• Speaker: Scott Chacon, co-founder of GitHub and author of 'Pro Git'
• New project: Working on a Git client called GitButler
• Focus: Technical discussion on Git, its commands, and new updates

Git Commands Overview

• Total Git Commands: ~145
  • Porcelain commands: 44 (e.g., add, commit, push, pull, rebase)
  • Manipulators: 11 (e.g., config, reflog)
  • Interrogators and Interactors: Includes commands like send-email
  • Plumbing commands: 63 (e.g., cat-file)
• Aim of Talk: Refresher and introduction to new commands
• Average updates: 9 commits/day, 10,000 commits in last 3 years

Configuration Tips

1. Aliases: For easier command executions
   • Example: alias.gl = git log --oneline
   • Use git stash --all for a cleaner stash
2. Include If: For specific configurations based on directory
   • Example: Separate configs for open-source projects and work projects

Oldies But Goodies

1. Git Blame: git blame and git blame -L for specific line ranges
2. Git Log: Use -L for function-specific logs
3. Whitespace Ignore: Using options like -w, -C, and -CCC
4. Git Word Diff: git diff --word-diff for more granular diffs
5. Reflog: View history of references with git reflog
6. Re-use Recorded Resolutions: rerere to auto-resolve recurring conflicts

New Features in Git

1. Branch Options:
   • -—column for column output
   • branch.sort for sorting branches by last commit
2. Force-With-Lease: Safe force push to avoid overwriting changes
3. SSH Signing of Commits: Option to use SSH keys for signing instead of GPG
4. Git Maintenance: Auto maintenance tasks like prefetching and commit graph generation

Large Repositories Support

1. Prefetching: Background fetching to speed up subsequent fetches
2. Commit Graph: Caches commit data for faster operations
3. File System Monitor (FS Monitor): Uses filesystem watchers to speed up git status
4. Partial Cloning: Allows downloading only portions of the repository
5. Sparse Checkout: Check out only specific subdirectories to handle large mono repos
6. Monorepo and Submodule Support: Various tips and tools to handle large project structures

New GitHub Features

• Allowed Merge Types: Configure which merge methods are allowed
• Auto Merge: Merge PRs automatically once CI passes
• Linear History Requirement: Enforce rebasing
• PR refs: Use local references to fetch and merge PRs

GitButler Project

• Emphasis on virtual branches to streamline multiple branches management without switching

Q&A Highlights

1. Range Diff: Discussed utility in specific workflows
2. Submodules Issue: Monorepos and package management as potential alternatives
3. Force with Lease: Discussion on making it the default
4. Future of Git: Ideas on improvements like working on multiple branches and auto-saving all changes.