Understanding Git Merge vs Rebase

Git is an essential version control tool, allowing developers to efficiently manage and track changes in their codebases. One of the fundamental ...

operations when working with Git branches is merging and rebasing. While both techniques are used to integrate changes from one branch into another, they have distinct differences that can impact your workflow. In this blog post, we'll explore what merging and rebasing are, how they differ, and which method might be more appropriate in different scenarios.

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1. What is Git Merge?
2. What is Git Rebase?
3. Key Differences Between Merge and Rebase:
4. Conclusion:

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1.) What is Git Merge?

Git Merge is the process of integrating changes from one branch into another. When you merge, Git creates a new commit that represents the union of two branches at the point of merging. This operation effectively combines the history of the source branch (the branch being merged) and the target branch (where the merge is performed).

How Merge Works:

1. Choose the Branch: Decide which branch you want to merge into another. Let's say you are working on a feature in `feature-branch` and want to integrate its changes into `main`.
2. Merge Command: Use the command `git merge <source-branch->>`, where `<source-branch->>` is the name of the branch you want to merge from. For example, `git merge feature-branch`.
3. Creating a Merge Commit: Git will create a new commit that combines all changes from both branches up to the point of merging. This creates a new commit in the target branch (e.g., `main`) that references commits from both branches.
4. Merge Conflicts: If there are conflicting changes, Git won't be able to automatically combine them and will prompt you to resolve conflicts manually by editing the files or using specific commands like `git add <file->>` for accepted changes and `git rm --cached <file->>` to remove conflicted content.
5. Completion: Once conflicts are resolved, commit the merge with a message explaining what was merged (`git commit`).

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2.) What is Git Rebase?

Git Rebase, on the other hand, involves applying commits from one branch onto another branch and effectively rewriting history. This means that instead of creating a new merge commit, rebase applies each commit in sequence to the target branch's tip.

How Rebase Works:

1. Choose the Branch: Decide which feature branch you want to integrate into another. Let's consider `feature-branch` and how its commits can be applied to `main`.
2. Rebase Command: Use the command `git rebase <source-branch->>`, where `<source-branch->>` is the name of the branch you want to rebase onto your current branch (you can also use `--onto` option if you are rebasing onto a different starting point).
3. Applying Commits: Git will replay each commit from `feature-branch` on top of `main`, effectively rewriting history and applying those commits one by one.
4. Resolving Conflicts: Similar to merge, rebase can lead to conflicts where changes have been made in both branches that Git cannot automatically resolve. You need to manually resolve these conflicts using `git add <file->>`.
5. Continuing the Rebase: Once all conflicts are resolved, continue the rebase with `git rebase --continue`. If there were no more conflicts, this will complete the process.
6. Completion: After resolving conflicts and continuing the rebase, Git applies the remaining changes from the source branch to the target branch.

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3.) Key Differences Between Merge and Rebase:

1. History Integrity: Merge maintains a linear history but can create more commits if there are merge commits. Rebase creates a new base for your branch that appears as if it was developed independently, which some consider cleaner and more linear in terms of commit history.
2. Conflict Resolution: Both operations can lead to conflicts, but rebase attempts to rewrite history to avoid making unnecessary merge commits, potentially reducing the number of conflicts.
3. Commit Message Impact: Merge retains original commit messages unless there are conflicts, while rebasing applies new commit messages that reflect changes on top of a different base. This might require updating commit messages after a rebase.
4. Maintaining Upstream History: Some teams prefer merge for preserving the full history and context of contributions from contributors. Rebase can be preferred when you want to present a cleaner, more linear contribution graph or when collaborating with other developers who are actively pushing new changes.
5. Usage Context: Use merge when you need to incorporate multiple branches' changes together without rewriting history significantly, which is typical in feature development phases where the full context of contributions matters. Rebase is ideal for scenarios requiring a more linear commit history or cleaner project structure, especially after reviews and before final merging into main.

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4.) Conclusion:

While both Git merge and rebase serve to integrate changes from one branch into another, they do so in fundamentally different ways. Understanding the nuances between these operations will allow you to choose the right tool for your workflow, whether it's maintaining a clear contribution history or keeping your project structure tidy post-review phases. Each approach has its pros and cons, and being aware of them can help you make more informed decisions about how to work with Git branches in your projects.

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The Autor: BetaBlues / Aarav 2025-06-15