Understanding Git Rebase: An Alternative to Merging

When learning Git, programmers typically start with commands like add, commit, push, pull, status, branch, checkout, and merge. After mastering these foundational commands, it's important to understand the rebase command.

Rebasing is often used as an alternative to merging. It updates one branch with the commits of another by applying the commits of one branch on top of the other. For example, if you're working on a feature branch that is out of date with a dev branch, you can rebase the feature branch onto dev to include all the new commits from dev. Here's a visual representation of this process:

Before Rebase

dev:     A---B---C---D
              \
feature:        E---F---G

After Rebase

dev:     A---B---C---D
                    \
feature:             E'---F'---G'

In command line, you can achieve this with:

git rebase dev feature

However, the more common approach is:

git checkout feature
git rebase dev

Typical Rebase Use Cases

Updating a Feature Branch

Imagine you're working on a feature branch, diligently adding commits.

feature:  E---F---G

Then you notice new commits on the dev branch that may impact your feature branch.

dev:     A---B---C---D
feature:  E---F---G

You decide to run git rebase dev from your feature branch to get up-to-date with dev.

git checkout feature
git rebase dev

During the rebase, conflicts may arise between your changes and the new commits on dev. Git will notify you of conflicts and the files that need resolution. After resolving conflicts, you add the changes with git add and continue the rebase process with git rebase --continue. If there are no more conflicts, your feature branch will be successfully rebased onto dev.

dev:     A---B---C---D
                    \
feature:             E'---F'---G'

Now, your feature branch includes the latest commits from dev, and you can continue working seamlessly.

Updating a Feature Branch Prior to Merge

Another common use for rebasing is to update a feature branch before merging it into the dev branch. Initially, the state of your branches might look like this:

dev:     A---B---C
              \
feature:        D---E

Once your feature is complete, you should rebase it onto dev before merging:

git checkout feature
git rebase dev

dev:     A---B---C
                    \
feature:             D'---E'

Next, merge your feature branch into dev. This is often done through a Pull Request for review. The result will be:

dev:     A---B---C---D'---E'

Rebasing before merging ensures that all commits from the feature branch appear at the end of the dev branch. This happens because rebasing rewrites commit history, giving new hashes and timestamps to the commits. Consequently, when you merge a rebased feature branch into dev, all the feature branch commits are ordered chronologically at the end.

Summary

Understanding how to rebase is essential for efficient Git workflows. Whether updating a feature branch with the latest changes from dev or preparing a branch for merging, rebase ensures a clean and organized commit history.

Understanding Git Rebase: An Alternative to Merging

Comments

More from this blog

I Built a Docker Security Scanner That Deploys Itself: Here's How A DevSecOps journey from code to production in 5 minutes

📰 GitOps CI/CD Pipeline

VIM Essentials: Think of It Like Working in the Cloud.

How to Configure a Local YUM Repository: The Interview Question Every Linux Admin Should Know

Understanding Linux File Permissions: A Visual Guide

After Rebase

Typical Rebase Use Cases

Updating a Feature Branch

Updating a Feature Branch Prior to Merge

Summary

Command Palette

Comments

More from this blog

After Rebase

Typical Rebase Use Cases

Updating a Feature Branch

Updating a Feature Branch Prior to Merge

Summary