GitHub

How to Merge Branches in GitHub

February 9, 2025

Merging branches in GitHub efficiently can change the way you handle code integration across multiple developers. Whether you’re managing a small repository or a significant open-source project, knowing how to merge branches in GitHub is crucial.

Understanding the process behind merging branches includes more than just a few commands; it involves strategic use of different branch types like feature and hotfix branches, managing merge conflicts, and ensuring smooth collaboration.

You will learn not only the steps to combine branches but also best practices for maintaining a clean and functional codebase.

By the end of this article, you’ll be adept at using GitHub’s CLI, creating pull requests, resolving conflicts, and more. I’ll also cover advanced topics like automating merges with GitHub Actions and how to handle continuous integration environments.

Let’s explore the essential commands, tools, and techniques you need to master for effective branch management in GitHub.

How To Merge Branches In GitHub: Quick Workflow

To merge branches in GitHub, follow these steps, which can be performed through the GitHub web interface or via the command line.

Merging Branches via the GitHub Web Interface

Create a Branch: Start by creating a new branch for your changes. In your repository, click on the Current Branch dropdown and select New Branch. Name your branch appropriately and make your changes.
Commit Your Changes: After making changes in your new branch, commit them with a descriptive message to document what you have done.
Open a Pull Request:
- Navigate to your repository and click on the Pull requests tab.
- Click on New pull request.
- Choose the base branch (typically main) and compare it with your newly created branch.
Review the Pull Request: After creating the pull request, you can review the changes. If everything looks good, you can proceed to merge.
Merge Options:
- Click on the Merge pull request button to merge all commits into the main branch.
- If you want to combine all commits into one, select Squash and merge.
- For rebasing commits onto the main branch, choose Rebase and merge.
Confirm Merge: After selecting your preferred merge option, leave a comment if desired, then click on Confirm merge. A confirmation message will appear if the merge is successful.
Delete the Branch (Optional): To keep your repository tidy, you can delete the merged branch by clicking on Delete branch.

Merging Branches via Command Line

If you prefer using Git from the command line, here’s how to do it:

Switch to the Target Branch: Use git checkout to switch to the branch you want to merge into (usually main):
git checkout main
Merge the Other Branch: Use git merge followed by the name of the branch you want to merge:
git merge feature-branch
This command will perform either a fast-forward or three-way merge depending on whether there are diverging changes.
Resolve Conflicts (if any): If there are any conflicts during merging, Git will notify you. You’ll need to resolve these conflicts manually before completing the merge.
Push Changes: Finally, push your changes to update the remote repository:
git push origin main

This process ensures that your code changes are integrated smoothly into the main project while maintaining a clear history of modifications.

Key Strategies for Merging Branches

maxresdefault How to Merge Branches in GitHub

Preparing for a Merge

Ensuring branch compatibility

Before thinking about how to merge branches in GitHub, you need to ensure both branches are compatible. Check branch history for conflicting changes. Always keep an eye on consistent coding styles. This step minimizes the issues later during the merge process.

Syncing branches to reduce conflicts

Sync your branches regularly. This involves continuous integration and syncing with the main branch. Frequent syncing catches conflicts early and makes the final merge process smoother. It’s simple: git fetch, then git rebase origin/main. Stay updated.

Types of Merges in Git

Fast-forward merges: Definition and use cases

A fast-forward merge moves the base branch pointer to the feature branch’s endpoint since there’s a straight line from start to finish. Simple and effective, but best for small, straightforward updates. No new commit is created.

Merge commits: Explanation and when to use

Merge commits are for complex histories. When branches diverge significantly, a merge commit creates a new commit that ties both histories together. It aids in tracking changes and keeps the branch history intact. Use this when changes are substantial.

Squash merges: Benefits and implementation

Squash merges compress all commits in a branch into a single commit on the target branch. This creates a clean history. Implement it by choosing “Squash and merge” during the merge process on GitHub. Perfect for cleaning up messy commit histories.

Rebase merges: Overview and workflow integration

Rebasing replays your branch changes onto another base branch, creating a linear history. While it’s great for a cleaner commit log, it can rewrite history. Handle with care. It’s done using git rebase command. Ideal for feature branches and ongoing projects.

Executing a Merge

Merging Branches Using GitHub

Steps to merge using the GitHub interface

Simple. Direct. First, navigate to your repository on GitHub. Choose the branch you want to merge into, typically main or master. Click on “New pull request.” Select your feature branch from the compare dropdown. Review your changes. Click “Create pull request.” Finally, if everything checks out, click “Merge pull request.” Done.

Selecting the appropriate merge option (fast-forward, squash, rebase)

GitHub offers multiple merge options. Choose wisely. Fast-forward creates a direct line. Squash merges compress all commits into one. Rebase combines changes into a fresh line. Select based on your needs. Click the dropdown next to “Merge pull request” and pick the appropriate option.

Merging Locally Using Git Commands

The git merge command: Syntax and options

Working locally? Use git merge. Switch to the branch you want to merge into with git checkout main. Now, execute git merge <feature-branch-name>. This integrates changes. Options include --no-ff to avoid fast-forward, or --squash to combine commits.

Example workflows for local branch merging

Example one: Fast-forward:

git fetch origin
git checkout main
git merge feature-branch

Example two: No fast-forward:

git fetch origin
git checkout main
git merge --no-ff feature-branch

Example three: Squash merge:

git fetch origin
git checkout main
git merge --squash feature-branch
git commit -m "Squash commit message"

Handling Merge Conflicts

Understanding Merge Conflicts

What causes merge conflicts?

Merge conflicts happen when two branches make different changes to the same line of a file, or when one branch edits a file while the other deletes it. Conflicts arise because Git can’t reconcile these differences automatically.

Identifying conflicts during a merge process

During the merge process, conflicts are flagged by Git. You’ll see conflict markers in the conflicting files (<<<<<<<, =======, >>>>>>>). Git will also alert you in the command line or GitHub interface, indicating which files need attention.

Resolving Conflicts

Manual resolution using conflict markers

Open the conflicted files. Look for conflict markers. The code between <<<<<<< HEAD and >>>>>>> reflects conflicting changes. Decide which changes to keep or combine them as needed. Remove conflict markers. Save the file.

Tools and techniques for resolving conflicts

Git mergetool: Use git mergetool to open a merge tool that helps visualize conflicts.
Visual editors: Editors like VSCode or Atom highlight conflicts and offer interfaces to resolve them.

Both tools provide a more intuitive way to handle conflicts, reducing manual errors.

Staging and committing resolved changes

Once conflicts are resolved, the next step is essential. Stage the changes using git add <file-name>. Commit the changes with a clear message, git commit -m "Resolved merge conflict in <file-name>". This finalizes the resolution process.

Best Practices for Avoiding Merge Conflicts

Keeping branches small and focused

Smaller, focused branches reduce the likelihood of conflicts. Make fewer, more manageable changes. This practice keeps the codebase clean and conflicts minimal. Aim for a single purpose per branch.

Regularly syncing with the main branch

Sync with the main branch often. Use git pull origin main to integrate any changes from the main branch into your working branch. This keeps your branch updated and conflicts minimal. Regular syncing is key to avoiding large, unexpected conflicts.

FAQ on How To Merge Branches In GitHub

How do I merge two branches in GitHub?

To merge two branches, first switch to the branch you want to merge into (usually the main branch). Use git merge <branch-name> to merge the changes. If there are conflicts, resolve them using your preferred text editor. Finally, commit the changes.

What is a pull request and how does it relate to merging?

A pull request is a way to notify others about changes in a branch that you want to merge. It allows collaborators to review the code, discuss potential issues, and approve the changes before they’re merged. It’s essential for collaboration on GitHub.

How can I resolve merge conflicts?

To resolve merge conflicts, open the conflicted files using your text editor. Look for conflict markers <<<<<<<, =======, and >>>>>>>. Choose which changes to keep or combine both changes as needed. Remove the conflict markers, then save and commit the resolved file.

What are the differences between merging and rebasing?

Merging combines different branches into one, preserving the commit history. Rebasing moves or combines a sequence of commits to a new base commit, creating a linear history.

Both have their uses; merging is straightforward, while rebasing can make the history cleaner but more complex.

How do I use GitHub Desktop to merge branches?

Open GitHub Desktop, select the current branch, and switch to the branch you want to merge into. Click on “Branch” and then “Merge into Current Branch”. Choose the branch to merge from the list, then follow any prompts to resolve conflicts and finalize the merge.

What should I do if a merge goes wrong?

If a merge goes wrong, use git merge --abort to stop the merge and return to the previous state. Alternatively, git reset --hard can revert to the last committed state. It’s crucial to regularly commit your work to avoid significant data loss.

What are fast-forward merges?

Fast-forward merges occur when the branch you are merging from is a direct ancestor of the target branch. Git simply moves the branch pointer forward without creating a new merge commit. Use git merge --no-ff to avoid fast-forward merges if you want a merge commit.

How do I merge branches in a forked repository?

First, update your forked repository by adding the original repository as a remote. Fetch the latest changes and then use git checkout to switch to the branch you want to update. Merge the updated branch and push the changes back to your forked repository.

What is a merge commit?

A merge commit is a special type of commit created when performing a non-fast-forward merge. It has two parent commits, representing the branches that were combined. This helps to track the merge history and understand which branches were merged and when.

How do I automate branch merging with GitHub Actions?

Create a .github/workflows directory in your repository and add a YAML file with the workflow definition. Configure the workflow to trigger on specific events like push or pull request. Use actions like actions/checkout and custom scripts to automate the merge process.

Conclusion

Mastering the process of how to merge branches in GitHub is an essential skill for efficient project management and collaboration. This guide has walked you through steps to merge branches, resolve conflicts, and use key tools like pull requests and GitHub Desktop.

Remember to create and manage feature branches, handle merge conflicts carefully, and automate your processes with GitHub Actions for better workflow. Effective use of pull requests can significantly improve code review processes and ensure high-quality merges.

By integrating these techniques, you’ll maintain a clean and functional codebase, enhancing your project’s stability and performance. Keep practicing, ensure your branch management is robust, and leverage the power of GitHub to streamline your development process. This knowledge will not only benefit your current projects but also position you as a more competent developer in the collaborative space.

If you liked this article about how to merge branches in GitHub, you should check out this article about how to delete a repository in GitHub.

There are also similar articles discussing how to clone a GitHub repository, how to use GitHub Copilot, how to add SSH key to GitHub, and how to pull from GitHub.

And let’s not forget about articles on how to delete a branch in GitHub, how to commit to GitHub, how to change GitHub username, and how to host a website on GitHub.

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Bogdan Sandu

Bogdan is a seasoned web designer and tech strategist, with a keen eye on emerging industry trends.

With over a decade in the tech field, Bogdan blends technical expertise with insights on business innovation in technology.

A regular contributor to TMS Outsource's blog, where you'll find sharp analyses on software development, tech business strategies, and global tech dynamics.