In this guide, we’ll compare Git merge and rebase, explain their use cases, and provide examples to help you decide when to use each. By mastering these concepts, you can handle branch integration with confidence and efficiency.

What is Git Merge?

Git merge combines changes from one branch into another, creating a new merge commit in the process. The history of both branches is preserved, making it easy to track the integration of changes.

For example, to merge a feature-login branch into the main branch:

git checkout main
git merge feature-login

This results in a new commit on the main branch that integrates changes from feature-login.

What is Git Rebase?

Git rebase moves the base of a branch to another branch, replaying commits from the source branch onto the target branch. Unlike merge, rebase rewrites the commit history.

To rebase feature-login onto main:

git checkout feature-login
git rebase main

This integrates changes from main into feature-login, but the history appears linear, as if all changes were made sequentially.

Merge vs. Rebase: Key Differences

When to Use Merge

• Collaborative projects: Use merge to preserve the history of contributions from different branches.
• Complex projects: Retain detailed commit histories to understand the evolution of the codebase.
• Default integration: When no specific need exists to rewrite history.

When to Use Rebase

• Linear history: Use rebase to create a clean, linear commit history before merging a feature branch.
• Small teams: Rebase is ideal when fewer contributors are involved, minimizing conflicts.
• Private branches: Safely rewrite history on branches that haven’t been shared with others.

Example: Merging in a .NET Project

Suppose you’re working on a feature branch for a .NET Framework project. The main branch has a Program.cs file with the following code:

// Program.cs in main branch
using System;

namespace MergeExample
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello from main!");
        }
    }
}

Your feature branch modifies the file:

// Program.cs in feature-login branch
using System;

namespace MergeExample
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello from feature-login!");
        }
    }
}

To merge the feature branch into the main branch:

git checkout main
git merge feature-login

The result will include both changes with a new merge commit.

Example: Rebasing in a .NET Project

If you rebase the feature-login branch onto the main branch:

git checkout feature-login
git rebase main

The commit history will appear as if all changes were made sequentially in the main branch.

Best Practices

• Collaborate with merge: Use merge for shared branches to maintain transparency.
• Clean up with rebase: Use rebase to tidy up feature branches before merging.
• Avoid rebasing public branches: Rewriting history on shared branches can cause conflicts.

Conclusion

Both Git merge and rebase are powerful tools for integrating changes. Choosing the right one depends on your project’s needs and collaboration style. By understanding their differences and use cases, you can confidently handle branch integration and maintain an effective version control system.