Coding, Software Development

Git Rebase vs. Merge: Workings, Differences, and Similarities

Written by Contributing Writer
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Updated on September 25, 2024

In the fast-paced world of software development, keeping track of code changes efficiently is crucial. That’s where Git comes into play. Git isn’t just another version control system; it’s a powerful tool that developers all over the world rely on every day. With its wide array of features, Git makes tracking and integrating changes a breeze.

One of the essential capabilities of Git is merging changes from different branches in a repository. Whether you’re collaborating on a team project or working solo, smoothly integrating these changes is vital. Git offers two main methods for this: Git rebase and Git merge.

At first, these techniques might seem a bit overwhelming or even intimidating. However, understanding their differences is key to effectively managing your code. This knowledge helps you maintain a clean and clear project history, making your life as a developer much simpler.

In this blog, we’ll break down the concepts of Git rebase and Git merge in a straightforward way. We’ll explore how each method works, highlight their similarities and differences, and delve into the pros and cons of each. By the end, you’ll have a solid grasp of when and how to use Git rebase and Git merge to keep your codebase organized and efficient. We also share a web development bootcamp you can take to gain the top software development skills to boost your career.

So, let’s dive in and explore these powerful Git commands.

What Is Git Rebase?

Git rebase is a game-changer when it comes to managing your development workflow. Picture this: you’ve been diligently working on a feature branch, and now it’s time to pull in the latest updates from the main branch. Instead of merging, which combines both branches’ histories into a new commit, rebasing takes your changes and re-applies them on top of the main branch’s latest commit. This process effectively moves your sequence of commits, creating a clean, linear project history that makes it easy to navigate and understand.

However, there’s a catch. Rebasing rewrites the commit history, which can spell trouble if you’re collaborating with a team. If your teammates have already pulled the original commits, rebasing can lead to conflicts and confusion. You’re essentially rewriting history, and that’s risky in a shared repository. So, while Git rebase is fantastic for maintaining a tidy and straightforward project timeline, it’s crucial to use it with caution and keep your team in the loop to avoid any potential hiccups.

What Is Git Merge?

Git merge is one of the cornerstone operations in Git that developers frequently use to integrate changes from one branch into another. Imagine you’re working on a feature branch while your teammate is making updates on the main branch. When it’s time to bring those changes together, Git merge steps in to help.

Merging creates a new commit, aptly named a “merge commit,” which serves as a bridge that combines the histories of both branches. This new commit has two parent commits: one from your feature branch and one from the main branch. As a result, it keeps a complete and detailed record of all changes made in both branches, ensuring nothing gets lost in the shuffle.

One of the biggest advantages of using Git merge is its ability to preserve the entire history of both branches. This comprehensive history can be incredibly beneficial for tracking the evolution of your project, allowing you to see how different features and fixes have developed over time.

In collaborative environments, merging is generally considered safer than rebasing. Why? Because it doesn’t rewrite or alter the existing commit history. This means there’s less risk of running into complex conflicts or inadvertently overwriting someone else’s work. Everyone’s contributions are preserved as they were originally committed, making it easier to manage shared repositories and maintain team harmony.

Also Read: All About the Software Development Life Cycle

Git Rebase vs. Merge: How They Work

Let’s see how Git rebase and Git merge work and what that means for your project.

When you use Git rebase, it’s like taking the changes from one branch and replaying them on top of another. Imagine you’ve been working on a feature branch with a series of commits. With rebase, each commit is applied to the target branch, creating new commits that look like they were made directly on top of that target branch. This process effectively shifts the entire feature branch to start from the tip of the target branch, making your project history look nice and linear as if all the work was done sequentially.

Now, compare this to Git merge. When you merge two branches, Git creates a special kind of commit called a merge commit. This merge commit has two parent commits, one from each branch being merged. It’s like a snapshot that combines the histories of both branches into one. So, instead of replaying commits, Git just joins the two branches together at that point in time, preserving the history of both branches as they were.

Rease rewrites history to create a straight line of commits, while merge keeps all the twists and turns, combining them at a single point. Each method has its strengths and can be incredibly useful depending on what you aim to achieve with your project’s history.

Similarities Between Git Rebase and Git Merge

When managing a project’s codebase with Git, rebase and merge are invaluable tools for integrating changes from one branch into another. Let’s delve into the similarities between these two methods:

Integration of Changes: At their core, Git rebase and merge are fundamental to integrating changes from one branch into another. Whether you’re reapplying commits or combining branch histories, both methods ensure your project’s progress is unified.
Conflict Resolution: Both techniques have conflict resolution capabilities. When concurrent changes cause conflicts, rebase and merge provide mechanisms to address these issues, allowing you to reconcile differences and maintain a consistent codebase.
Version Control Maintenance: Maintaining a coherent project history is crucial in the context of version control. Git rebase and merge are essential tools that help achieve this goal, ensuring that changes are tracked and managed effectively.
Commit History Management: While they handle history differently, rebase and merge ultimately aim to manage and maintain your commit history. Rebase creates a linear sequence of commits, while merge preserves the original history. Both methods strive to keep your project’s history organized.
Collaboration: In a collaborative environment, Git rebase and merge play vital roles in integrating work from multiple team members. They allow you to incorporate changes from different branches, ensuring everyone’s contributions are included in the final project.

Also Read: What is Software Testing in Software Engineering?

Git Merge vs. Rebase: Differences

Let’s understand how Git rebase and merge work and what they mean for your project. Here’s a more detailed look at their differences:

Difference	Git Rebase	Git Merge
History Management	Think of rebase as rewriting history to create a seamless story. When you rebase, you take each commit from your feature branch and apply it individually to the target branch. This process makes your project history look like a straight line, with all the commits appearing as if they were made sequentially, without any branches.	In contrast, merging preserves the history of both branches. When you merge, Git creates a new commit with two parent commits, one from each branch combined. This merge commit acts like a bridge, joining the histories of the branches at that point. Your history retains all the twists and turns, showing exactly how the development progressed on each branch.
Commit Handling	Rebasing applies individual commits from one branch to another. This means each commit from the feature branch is replayed on the target branch, creating new commits that appear as if they were part of the target branch from the start.	Merging, on the other hand, combines the histories of both branches into a single commit. This merge commit encapsulates all the changes from both branches up to that point, maintaining the original commits without altering them.
Conflict Resolution	When you rebase, you might encounter conflicts that must be resolved for each commit being applied. If a conflict appears in several commits, you could resolve it multiple times.	Merging typically requires resolving conflicts only once, at the point of the merge commit. This can make conflict resolution more straightforward since you handle all the conflicts simultaneously.
Branch History	After a rebase, the feature branch starts from the tip of the target branch. This can make your history cleaner and easier to follow, especially when looking at the commit log. All the work was done sequentially, even if it was done in parallel on different branches.	With a merge, the history shows the parallel development of both branches. The merge commit marks the point where the branches were combined, preserving the complete history of both branches before the merge. This can be useful for understanding the context and progression of changes.
Usage Scenarios	Rebase is useful for cleaning up a messy history before merging changes into a main branch. It’s great for making the commit log more readable and integrating long-running feature branches without cluttering the history of multiple merge commits.	Merge is often the go-to choice for combining branches in collaborative environments. It’s safer because it doesn’t rewrite history, making it easier to manage shared repositories. It’s also beneficial when you want to maintain a complete and detailed record of the project’s evolution.

Git Rebase vs Git Merge: Advantages and Disadvantages

When deciding between Git rebase vs. merge, it’s important to weigh their advantages and disadvantages, especially when working in a team. Let’s break down what makes these Git features unique and when you might want to use one over the other.

	Advantages	Disadvantages
Git Rebase	Cleaner History: Git rebase creates a linear project history, which means you get a straight line of commits. This can make your project history look much cleaner and more organized. Simplified Commit History: With a rebased history, you can easily follow the development timeline without dealing with numerous branches and merging commits. Easier to Understand: A linear history is easier for new team members or contributors trying to get up to speed with the project. Better Bisecting: Debugging issues with ‘git bisect’ becomes simpler with a linear history. Eliminates Merge Commits: By using rebase, you can avoid the clutter of multiple merge commits in your history. Customizable Commits: Rebase allows you to edit commit messages and squash commits, which can be useful for cleaning up your commit history before merging. Consistent Project Timeline: With rebase, the project timeline remains consistent, making it easier to see when specific changes were made. Maintains Context: Rebase keeps the context of the changes clear by applying commits in a logical order. Integrates Changes Smoothly: Rebasing can integrate changes more smoothly when you’re working on a feature branch and need to incorporate updates from the main branch. Ideal for Small Teams: Rebasing can be an excellent way to keep the project history tidy in smaller teams or solo projects.	History Rewriting: Rebase rewrites commit history, which can be problematic in collaborative environments where others might have based their work on the original commits. Complex Conflicts: Resolving conflicts during a rebase can be complex and may need to be done multiple times if the same conflict arises in different commits. Potential Data Loss: If not done carefully, there’s a risk of losing commits, especially when dealing with a shared repository. Collaboration Issues: Rebasing can lead to confusion and conflicts when working with a team, as it changes the commit hashes and history. Dangerous for Shared Branches: Rebasing public or shared branches is risky and can disrupt other team members’ work. Requires Careful Coordination: Team members must coordinate carefully when using rebase to avoid issues with conflicting histories. Not Ideal for Long-Running Branches: Rebasing long-running branches can become cumbersome and lead to significant merge conflicts. Learning Curve: Rebase has a steeper learning curve and can be intimidating for new Git users. Time-Consuming: The rebasing process can be time-consuming, especially when dealing with conflicts. Risk of Mistakes: Mistakes during rebase can be harder to correct than those during merge, which can be more forgiving.
Git Merge	Preserves History: Git merge keeps the complete history of changes, which is beneficial for tracking the project’s evolution. Safer for Teams: Merge is safer for collaborative work since it doesn’t rewrite history, avoiding potential issues with conflicting histories. Single Conflict Resolution: Conflicts are resolved once the merge commit is completed, simplifying the conflict resolution process. Clear Merge Points: Merge commits show where two branches were combined, providing context for future reference. Less Risk of Data Loss: Since it doesn’t rewrite history, there’s less risk of losing commits or changes. Works Well with CI/CD: Merging is often more compatible with Continuous Integration/Continuous Deployment (CI/CD) workflows, where maintaining a full history is crucial. Ideal for Shared Repositories: Merging is a better choice for shared repositories, minimizing disruption for other contributors. Simpler for New Users: Merge is easier for new Git users to understand and use without worrying about altering commit history. Handles Complex Histories: Merge can handle complex branch histories without requiring a deep understanding of the project’s commit structure. Easier to Undo: Undoing a merge is straightforward compared to a rebase, making it more forgiving when mistakes happen.	Cluttered History: Merge commits can clutter the project history, making it harder to follow the development timeline. More Complex History: The commit history can become complex and harder to understand, especially with multiple merge commits. Difficult Navigation: Navigating a project’s history with many merges can be challenging and time-consuming. Merge Conflicts: Although conflicts are resolved once, they can still be difficult and time-consuming during the merge process. Not as Clean: The project history with merges is not as clean and linear as with rebasing, which can be a drawback for some teams. Less Customization: Merging doesn’t offer the same level of customization for commit messages and history as rebasing does. Potential for Redundant Merges: In projects with frequent merges, redundant merge commits that don’t add much value can exist. Slower CI Builds: Merge commits can lead to slower continuous integration builds due to the additional history needed to process. Harder to Identify Changes: Identifying specific changes in a merge commit can be more difficult than a linear history. Potential for Merge Hell: In complex projects, multiple branches and frequent merges can lead to what’s known as “merge hell,” where resolving conflicts becomes a major headache.

Also Read: Web Development Tutorial: What is Unit Testing in Python?

How to Use Git Rebase and Git Merge Together

Combining Git rebase and Git merge can be a powerful strategy for maintaining a clean and organized project history while effectively managing branches. Here’s how to leverage both techniques to get the best of both worlds.

1. Start with a Feature Branch

When you begin working on a new feature, create a new branch off the main branch (often ‘main’ or ‘master’):

git checkout -b feature-branch

2. Rebase Regularly to Keep Up-to-Date

As you develop your feature, keeping your branch up-to-date with the latest changes from the main branch is essential. This is where rebasing comes in handy. Regularly rebase your feature branch onto the main branch to incorporate the latest changes:

git checkout feature-branch

git fetch origin

git rebase origin/main

Doing this ensures that your feature branch is always in sync with the main branch, minimizing the risk of conflicts when you merge.

3. Resolve Conflicts During Rebase

If conflicts occur during the rebase process, Git will pause and allow you to resolve them. After resolving the conflicts, use the following commands to continue rebasing:

git add .

git rebase –continue

Repeat this process until the rebase is complete.

4. Complete Your Feature Development

Continue working on your feature branch, making commits as needed. Since you’re rebasing regularly, your branch will remain current with the main branch.

5. Perform a Final Rebase Before Merging

Before merging your feature branch into the main branch, perform a final rebase to ensure it’s fully up-to-date:

git checkout feature-branch

git fetch origin

git rebase origin/main

Resolve any conflicts that arise during this rebase.

6. Merge Your Feature Branch into the Main

Once the final rebase is complete and your feature branch is ready, switch to the main branch and perform the merge:

git checkout main

git merge feature-branch

The merge should be straightforward and conflict-free since you’ve kept your feature branch up-to-date with regular rebasing.

7. Push Your Changes

Finally, push the updated main branch to the remote repository:

git push origin main

What is Git Reset?

Git reset is a powerful command in Git that allows you to undo changes in your repository. It can move the current branch to a specified commit, erasing the commits that follow it. This command has three modes: soft, mixed, and hard.

Soft Reset: Moves the HEAD to the specified commit but keeps the changes in the staging area.
Mixed Reset: This resets the HEAD to the specified commit and resets the staging area but leaves the working directory unchanged.
Hard Reset: Moves the HEAD to the specified commit and resets the staging area and the working directory, erasing all changes.

Git reset is a powerful tool for undoing mistakes, but it should be used with caution. If not handled properly, it can permanently remove changes.

Also Read: What Does a Software Engineer Do?

Difference Between Squash and Merge, and Rebase and Merge

Squash and Merge

Squash and merge is a Git feature that combines multiple commits into a single commit before merging a branch into the main branch. This technique is useful for cleaning up a messy commit history. Instead of preserving each commit, it consolidates them into one, making the history easier to read.

Key Points:

Combines multiple commits into one.
Keeps commit history clean and concise.
Ideal for merging feature branches with lots of minor commits.

Rebase and Merge

Rebase and merge involves using the rebase command to move the entire feature branch onto the tip of the main branch before merging. This process rewrites the commit history, creating a linear sequence of commits.

Key Points:

Reapplies commits from the feature branch onto the main branch.
Creates a linear commit history.
Can lead to conflicts that need to be resolved multiple times.

Which is Better, Git Rebase or Merge?

The choice between rebase and merge depends on your project’s needs and your team’s workflow.

Rebase

Pros

Cleaner History: Creates a linear, easy-to-follow commit history.
Bisecting: Easier to use git bisect to find bugs.

Cons

Rewrite History: Changes commit hashes, which can be problematic for shared branches.
Conflict Resolution: This may require resolving conflicts multiple times.

Merge

Pros

Safe for Collaboration: Does not rewrite history, making it safer for shared branches.
Single Conflict Resolution: Conflicts are resolved once in the merge commit.

Cons

Messy History: Creates a more complex commit history with merge commits.
Potentially Confusing: Can make the history harder to follow.

Git Rebase vs. Merge: Summary

Use rebase for a clean, linear history and when working on feature branches locally.
Use merge when working in a collaborative environment to avoid rewriting history and ensure a clear record of how branches were integrated.

Upskill to Learn the Latest Web Development Skills, Tools, and Techniques

Mastering Git rebase and Git merge is key for web developers to keep their codebases organized and efficient. Git rebase creates a clean, linear history in solo projects or small teams. In contrast, Git merge is safer and better suited for larger, collaborative projects where preserving the entire project history is essential. By correctly understanding and applying these tools, you can improve your development workflow, seamlessly integrate changes, and maintain your project’s history.

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