Git Merge, Rebase, and Squash: Key Differences and Best Practices

Introduction

• Common issue: Deciding whether to use git merge, git rebase, or squash commits
• Objective: Breakdown the key differences and when to use each command in a workflow

Main Content

Scenario Setup

• *Feature branch vs. Main branch:
  • Created new feature branch from main
  • Feature branch commits: A, B, C
  • Main branch commits: D, E
• Visual analogy: Two branches of a tree growing in different directions
• Goal: Keep feature branch up to date with main using git merge or git rebase

Git Merge

• Description: Pulls in latest changes from main into the feature branch, creating a new "merge commit"
• Analogy: Tying two branches together with a knot
• Result: Complete picture of commit history but can become messy with many merge commits

Git Rebase

• Description: Changes the base of the feature branch to the latest commit on main and replays changes from there
• Result: Clean, straightforward commit history

Getting Feature Branch Back to Main

• Options:
  • Git Merge: Creates a new "merge commit" that ties histories of both branches
    • Analogy: Knot in the rope showing where branches joined
    • Note: Can result in messy history with multiple merge commits
  • Git Rebase and Fast-Forward Merge: Moves feature branch's changes to the tip of main; then fast-forward merge
    • Analogy: Straightening out the rope for a linear history
  • Squash Commits: Combines all feature branch commits into a single commit
    • Result: Linear history in main, loss of detailed commit history
    • Popularity: Common on platforms like GitHub for tidy main branch history
    • Hybrid approach: Preserves detailed commit history in the feature branch

Summary

• Git Merge: Provides a complete picture of commit history and branch evolution
• Git Rebase: Tidies up history by moving commits to the main branch tip
• Squashing: Consolidates commits for clean, linear main branch history at the cost of detailed history

Considerations

• Team Values: Clean history vs detailed commit history
• Choosing strategy: No one-size-fits-all; evaluate pros and cons based on team needs

Call to Action

• Discussion: Have you used these strategies? Which one do you prefer and why?
• Newsletter: Subscribe to the system design newsletter at blog.bytebytego.com, trusted by 450,000 readers