Git Rebase Vs Merge

Git rebase and merge are git two utilities that are designed to combine changes from one branch to another branch. This means that Git offers two primary methods for bringing changes from one branch into another: merge and rebase.

Rebasing takes a series of commits from one branch and applies them on top of another branch. This is like picking up your changes from your branch and placing them on top of a different branch. It makes it look as if you developed your changes directly on the other branch.

Git Merge works as same but can develop a new commit that can integrate the changes from two branches. Each has its own advantages and use cases. Let’s explore the differences and details of both:

Git Merge

Merging Strategy: When you perform a merge, Git creates a new merge commit that has two parent commits — the commit of the current branch and the commit from the branch being merged. This results in a merge history that shows all the individual branch histories.

Merge Commits: Merge commits often clutter the commit history, making it more challenging to track the individual changes made on each branch.

Use Case

• Merging is typically used for integrating feature branches into a main or stable branch.
• It’s a safe choice when you want to preserve the history of each branch and want to maintain a clear distinction between different lines of development.

Commands:

• To merge a branch into the current branch: git merge <branch_name>.

Git Rebase

Rebasing Strategy: When you perform a rebase, Git essentially moves or “replays” the commits from the current branch on top of the branch you’re rebasing onto. It doesn’t create merge commits. This results in a linear commit history.

Commit History: Rebasing keeps the commit history cleaner and linear. It makes it easier to follow the chronological order of changes.

Use Cases:

• Rebasing is often used when you want to incorporate the latest changes from the target branch into your feature branch.
• It’s also helpful for creating a linear, more readable history before merging your changes into the main branch.

Commands:

• To rebase the current branch onto another branch: git rebase <branch_name>

When to Choose Git Merge and Git Rebase?

• Use merge when you want to maintain a clear history of each branch’s development and when a non-linear history is acceptable.
• Use rebase when you want a linear, cleaner history, or when you need to update your feature branch with the latest changes from the main branch.

Lets go through one scenario to understand more clearly.

Using Git Merge:

First, you are on the feature branch, and you want to integrate your changes into the main branch using git merge

# On the feature branch
git merge main        

When you merge feature into main, Git creates a new merge commit with two parent commits, one from feature and one from main. This results in a branching commit history:

*   Merge branch 'feature' into 'main'
|\
| * Commit F3 (feature)
| * Commit F2
|/
* Commit M2 (main)
* Commit M1        

In the history, you can see a clear distinction between the main and feature branches, but the merge commit adds some noise to the history.

Using Git Rebase:

First, you are on the feature branch, and you want to integrate your changes into the main branch using git rebase

# On the feature branch
git rebase main        

When you rebase feature onto main, Git replays the commits from feature on top of main. This results in a linear commit history without merge commits:

* Commit F3 (feature)
* Commit F2
* Commit M2 (main)
* Commit M1        

With rebase, you have a clean, linear history that makes it easier to understand the chronological order of changes. The downside is that it appears as if the feature branch was developed directly on top of main.