Rebase & Merge

Understanding the Differences Between Git Rebase and Merge

When working with Git, managing branches and combining changes from one branch to another are common tasks. Two main approaches to do this are rebase and merge. Though they serve a similar purpose, each has distinct characteristics and use cases. In this post, we'll explore how rebase and merge work and when to use each.

What Happens When You Create and Switch to a New Branch?

When you create a new branch from your current branch, the new branch inherits all the changes and history up to that point. For example, if you are on the main branch and create a new branch called feature-branch, this new branch will have the exact same commits as main at the moment of creation. From that point on, changes made in feature-branch will not affect main unless you explicitly merge or rebase them.

What Does Merge Do?

The merge command combines changes from one branch into another by creating a new commit that represents the combination of both branches' histories. This is how it works:

• How Merge Works: Merge takes the content of the feature branch and merges it into the main branch, creating a new merge commit.
• Benefits of Merge: Keeps the history of both branches intact and is straightforward to use, making it ideal for larger teams or projects that require detailed tracking of all changes.
• Downsides of Merge: Can make the commit history look messy with multiple branches merging in different directions, which can be confusing when navigating through the project's history.

What Does Rebase Do?

The rebase command, on the other hand, rewrites the history of a branch by moving or "rebasing" its commits on top of another branch. This effectively creates a linear, clean commit history.

• How Rebase Works: Rebase moves your feature branch commits on top of the main branch, creating a clean, linear history without merge commits.
• Benefits of Rebase: Provides a much cleaner project history, making it easier to understand the sequence of changes.
• Downsides of Rebase: Since it rewrites history, it can be dangerous in a team setting where others may be working on the same branch. Conflicts can also occur, requiring manual resolution.

After Rebase: Continuing Your Work

After performing a rebase, you continue working on your feature branch. Any new changes you make will be added to this branch. The branch remains independent until you decide to merge or rebase it again with the main branch. Rebase can keep your commits tidy and easy to follow, but you must handle conflicts carefully.

When to Use Merge vs. Rebase

• Use Merge: When you want to preserve all details of the project history, and when working in larger teams where rewriting history can cause issues.
• Use Rebase: For smaller projects or personal branches where maintaining a clean, linear commit history is more valuable. Avoid using rebase on shared branches.

Conclusion

Choosing between merge and rebase depends on your project's needs and your team's workflow. Merge keeps a full and intact history but can make it messy, while rebase offers a cleaner history at the cost of rewriting commit history. Use merge when in doubt or working with others, and rebase when you want clarity and are confident in handling conflicts.

By understanding these differences and applying them correctly, you can maintain a more organized and efficient Git workflow. Happy coding!