Git Rebase vs Merge: When to Use Each

You should use Git rebase when you want to maintain a clean, linear project history by incorporating changes from one branch into another without creating merge commits. Git merge combines branches by creating a new merge commit that preserves the actual history, while Git rebase moves or re-applies commits from one branch onto another, creating a new linear sequence. After a successful rebase, you typically don’t need to perform a merge unless you’re merging back to a shared branch, and this approach significantly simplifies your Git workflow by avoiding unnecessary merge commits and making the history easier to follow and understand.

Contents

• Understanding Git Rebase vs Merge
• When to Use Git Rebase
• When to Use Git Merge
• Key Differences Between Rebase and Merge
• Do You Need to Merge After Rebasing?
• Workflow Implications
• Best Practices and Considerations

Understanding Git Rebase vs Merge

Git rebase and Git merge are two fundamental operations for integrating changes from one branch into another, but they approach this task in fundamentally different ways that affect your project’s history and workflow.

Git merge creates a new “merge commit” that combines the histories of two branches. This commit has two parents: the tip of the current branch and the tip of the branch you’re merging. This preserves the actual historical timeline and shows when two lines of development diverged and came back together.

Git rebase takes the commits from your current branch and re-applies them on top of another branch. Instead of creating a merge commit, it creates entirely new commits that are identical in content but have different parents, effectively rewriting history to create a linear timeline.

# Example of merge
git checkout feature
git merge main

# Example of rebase
git checkout feature
git rebase main

The choice between these operations has significant implications for collaboration, history readability, and long-term project maintenance.

When to Use Git Rebase

You should use Git rebase in several key scenarios where maintaining a clean, linear history is important:

Local Branch Cleanup

When working on a feature branch that hasn’t been shared with others, rebase is ideal for keeping your commits clean and organized. This is particularly useful when you’ve made multiple commits that could be better structured as logical units.

# Interactive rebase to clean up commits
git rebase -i HEAD~3

Integrating Changes from Main

When you need to pull in the latest changes from the main branch into your feature branch, rebase helps avoid unnecessary merge commits. This creates a linear history that’s easier to follow and understand.

# Keep your branch up to date with main
git rebase main

Creating Pull Requests

Many teams prefer rebase-based workflows for pull requests because they create cleaner PRs with linear histories that are easier to review and understand. This eliminates confusing merge commits from the PR view.

Personal Feature Development

For personal projects or when working alone, rebase provides maximum flexibility to reorganize, squash, or split commits before integrating them into the main branch.

When to Use Git Merge

Git merge is preferable in several important scenarios:

Preserving Complete History

When you need to maintain the complete historical record showing when branches diverged and reconverged, merge is the better choice. This is crucial for auditing, debugging, and understanding the evolution of complex features.

Collaborative Branches

When working with shared branches that other team members are actively using, merge is safer because it doesn’t rewrite history. This prevents conflicts and confusion in collaborative environments.

Stable Release Branches

For release branches or maintenance branches where you need to clearly track when fixes were integrated, merge provides better visibility into the integration timeline.

Avoiding Rewriting History

When you’re uncertain about the history of a branch or when working with public repositories, merge is the safer option because it doesn’t rewrite existing commits that others might have based their work on.

Key Differences Between Rebase and Merge

History Structure

The most fundamental difference is how they handle project history:

Conflict Handling

Both operations handle conflicts, but differently:

• Merge: Conflicts occur during the merge commit creation. You resolve conflicts and commit the merge.
• Rebase: Conflicts occur when reapplying each commit. You resolve conflicts and continue the rebase with git rebase --continue.

Performance Considerations

• Merge: Generally faster for large repositories with many branches
• Rebase: Can be slower for complex histories due to reapplying commits

Safety and Reversibility

• Merge: Easy to revert with git revert
• Rebase: Rewrites history, making it harder to undo without careful branch management

Do You Need to Merge After Rebasing?

The answer depends on your workflow and branch strategy:

Local Development Workflow

When rebasing a local feature branch that hasn’t been pushed to a remote repository, you typically don’t need to merge afterward. The rebase directly incorporates changes into the target branch.

Remote Branch Integration

After rebasing a branch that has been shared with others, you’ll need to force push (git push --force) to update the remote branch. Then, when merging back to main or another shared branch, you may want to use a merge to create a merge commit that documents the integration.

Pull Request Workflows

In GitHub/GitLab workflows, after rebasing your feature branch, you still need to create a merge (either via merge commit or squash merge) to integrate the changes into the target branch. The rebase cleans up your history, but the final integration still requires a merge operation.

Hybrid Approach

Many teams use a hybrid approach:

1. Use rebase locally to clean up commits
2. Use merge for the final integration into shared branches

This combines the benefits of both operations while minimizing their drawbacks.

Workflow Implications

Rebase-First Workflow

Main branch: A → B → C → D
Feature branch: A → E → F

After rebase:
Main branch: A → B → C → D
Feature branch: A → B → C → D → E' → F'

Merge-First Workflow

Main branch: A → B → C → D
Feature branch: A → E → F

After merge:
Main branch: A → B → C → D → G (merge commit)
Feature branch: A → E → F

Team Collaboration Impact

• Rebase workflows require team coordination and clear communication about when it’s safe to rebase
• Merge workflows are more forgiving for team collaboration but create more complex histories
• Mixed workflows can work well but require clear documentation and standards

CI/CD Pipeline Considerations

• Rebase workflows may require pipeline adjustments to handle force pushes
• Merge workflows integrate more naturally with most CI/CD systems
• Both approaches need careful handling of branch protection rules

Best Practices and Considerations

Rebase Best Practices

1. Never rebase shared branches that others are actively working on
2. Always create backups before force pushing after rebase
3. Use interactive rebase (git rebase -i) to clean up commits
4. Communicate with your team about rebase operations

Merge Best Practices

1. Use descriptive merge commit messages to document integration points
2. Consider using squash merge for pull requests to keep history clean
3. Set up branch protection rules to prevent accidental force pushes
4. Document your merge strategy in team guidelines

Choosing the Right Approach

Consider these factors when deciding between rebase and merge:

• Team size and collaboration patterns
• Project complexity and history requirements
• Review process and pull request workflow
• Documentation and auditing needs
• Team experience with Git workflows

Many successful teams use a context-dependent approach, using rebase for local development and merge for shared branch integration, creating the best of both worlds while minimizing potential conflicts.

Conclusion

Git rebase and merge serve different purposes in version control workflows, with rebase being ideal for maintaining clean, linear histories in local development, while merge provides better history preservation for collaborative work. After a successful rebase, you typically don’t need to perform another merge unless you’re integrating back into a shared branch, though the final integration may still require a merge operation to create proper documentation of the integration point. The choice between these operations depends on your team’s workflow, collaboration needs, and how much emphasis you place on history readability versus preservation. Many teams find success in using a hybrid approach that leverages rebase for local cleanup and merge for shared branch integration.

Sources

1. Atlassian Git Documentation - Rebase vs Merge
2. Pro Git Book - Rebasing
3. GitHub Documentation - Rebasing
4. Git Official Documentation - Merge
5. Stack Overflow - When to use rebase vs merge