How to Merge a Pull Request on GitHub?

GitHub is a powerful platform that enables developers to collaborate on software projects by using Git, a version control system.

One of the most common ways developers collaborate is through pull requests (PRs). A pull request allows developers to propose changes to a repository by submitting their code changes for review. Once reviewed and approved, these changes are merged into the main codebase.

In this blog post, we will walk you through the process of merging a pull request on GitHub. Whether you’re a team lead, project maintainer, or contributor, understanding how to merge pull requests is crucial for ensuring smooth collaboration and efficient workflow.

What is a Pull Request?

A pull request is a request to merge one branch into another (typically, into the main or master branch) in a Git repository. When you create a pull request, you’re asking the project maintainers to review and merge your changes into the target branch. Pull requests are commonly used in collaborative projects, enabling other developers to review the changes before they are merged into the main codebase.

Here’s the typical flow of a pull request:

1. Fork or clone the repository.
2. Create a new branch to work on your changes.
3. Make changes and commit them to the branch.
4. Push the branch to GitHub and create a pull request.
5. Review the pull request by other developers.
6. Merge the pull request into the main branch if everything looks good.

Why Merge a Pull Request?

Merging a pull request is a critical step in any collaborative software development workflow. When you merge a pull request, you:

• Integrate new features or bug fixes into the main branch of the repository.
• Collaborate with other developers, ensuring their changes are reviewed and tested before being included in the codebase.
• Maintain a clean and manageable codebase, with each set of changes clearly documented in the pull request.

Step-by-Step Guide to Merging a Pull Request on GitHub

Step 1: Open the Pull Request

1. Navigate to Your Repository: Go to the GitHub repository where the pull request has been submitted.
2. Find the Pull Request: On the repository’s main page, click on the Pull requests tab. This will show a list of open pull requests.
3. Select the Pull Request: Click on the pull request that you want to merge. This will open the detailed view of the pull request, where you can see the changes, discussions, and review comments.

Step 2: Review the Changes

Before merging a pull request, it’s important to review the changes to ensure that they meet the project’s standards and do not introduce any issues. Here’s what you should do:

1. Review the Files Changed: On the pull request page, you can view the list of files that have been changed. GitHub provides a diff view, showing additions and deletions line-by-line.
   • Look for coding standards, tests, and documentation updates.
   • Check for conflicts: If there are conflicts between the pull request and the base branch (e.g., main), they will be highlighted.
2. Check for Automated Tests: If your project uses continuous integration (CI), check the status of automated tests that are triggered by the pull request. Ideally, all tests should pass before merging.
3. Read Comments and Approvals: Ensure that any comments or requests from reviewers have been addressed, and that at least one team member has approved the changes. Some repositories may require approvals before a pull request can be merged.

Step 3: Merge the Pull Request

Once you are satisfied with the changes and the pull request is ready for merging, follow these steps:

1. Choose the Merge Option: On the pull request page, you will see a green button labeled Merge pull request. Click on the button to initiate the merge process. GitHub provides three main merge strategies:
   • Merge commit: This is the default option. It creates a merge commit, preserving the history of both the source branch and the target branch. This method is ideal when you want to keep a detailed record of changes.
   • Squash and merge: This option combines all commits from the feature branch into a single commit before merging. This is useful for keeping the main branch’s history clean and concise.
   • Rebase and merge: This option rebases the feature branch onto the target branch before merging, creating a linear history. It’s useful for projects that prefer a cleaner, linear commit history.
2. Confirm the Merge: After selecting your preferred merge strategy, GitHub will prompt you to confirm the merge. You can also edit the commit message if necessary.
   • For squash and merge and rebase and merge, you’ll be prompted to write a commit message summarizing the changes.
   • For merge commit, GitHub will automatically generate a merge commit message, but you can customize it if needed.
3. Click Merge: Once you’re ready, click the Confirm merge button. GitHub will merge the pull request into the target branch (usually main or master).

Step 4: Delete the Branch (Optional)

After merging the pull request, you can delete the source branch (the feature or bugfix branch) to keep your repository clean. GitHub provides an option to delete the branch immediately after the merge:

1. Click Delete Branch: After merging, GitHub will display a button to delete the branch. Click Delete branch to remove it from the repository.
2. Clean Up Locally: If you’ve cloned the repository locally, you can delete the branch from your local machine as well: git branch -d <branch-name>

Best Practices for Merging Pull Requests

1. Review Thoroughly: Always review the pull request carefully to ensure the changes are correct, complete, and align with the project’s goals. Use GitHub’s comment and review features to leave feedback or request changes before merging.
2. Use Merge Commit for Context: Use the default Merge commit strategy when you want to keep a detailed history of feature branches or bug fixes.
3. Squash Small Changes: Use Squash and merge for minor changes or small feature additions that don’t require a detailed commit history.
4. Rebase for Clean History: Use Rebase and merge if you want to maintain a linear, clean commit history without merge commits.
5. Automate Testing: Ensure that all automated tests pass before merging, and consider using a continuous integration (CI) tool to automate this process.
6. Communicate with Your Team: Ensure that the pull request is reviewed and approved by your team members before merging. Communication is key to a successful collaboration.

Conclusion

Merging pull requests is a fundamental part of collaborative software development on GitHub. By following the steps outlined in this blog, you can ensure that changes are thoroughly reviewed, properly integrated, and added to the project’s main codebase.

Whether you’re merging for bug fixes, new features, or documentation changes, GitHub makes it easy to collaborate and manage contributions from different developers.

By adhering to best practices and choosing the right merge strategy for your project, you can maintain a clean, organized, and efficient repository.