Code Reviews on GitHub

Code reviews are a critical part of collaborative development, helping maintain code quality, share knowledge, and catch bugs before they reach production.

What is a Code Review?

A code review is the process of examining code changes before they are merged into the main codebase. On GitHub, this happens through Pull Requests (PRs).

Benefits of Code Reviews

• Quality assurance: Catch bugs and issues early
• Knowledge sharing: Team members learn from each other
• Code consistency: Maintain coding standards across the team
• Documentation: PRs serve as a record of why changes were made
• Security: Identify potential security vulnerabilities

How to Conduct a Code Review

1. Understand the context: Read the PR description and related issues
2. Review the changes: Look at the diff and understand what changed
3. Test the changes: Pull the branch locally if needed
4. Provide feedback: Leave comments on specific lines
5. Make a decision: Approve, request changes, or comment
6. Follow up: Ensure feedback is addressed

Best Practices for Reviewers

What to Look For

• Correctness: Does the code do what it's supposed to do?
• Clarity: Is the code easy to understand?
• Performance: Are there any performance issues?
• Security: Are there any security vulnerabilities?
• Testing: Are there adequate tests?
• Documentation: Is the code properly documented?

How to Give Feedback

• Be specific: Point to exact lines that need attention
• Be constructive: Suggest improvements, not just problems
• Ask questions: Use questions to understand intent
• Praise good work: Acknowledge well-written code
• Focus on the code: Review the code, not the coder

Best Practices for Authors

Before Requesting Review

• Self-review first: Review your own changes before submitting
• Write clear descriptions: Explain what changes were made and why
• Keep PRs focused: Make one logical change per PR
• Add tests: Include appropriate test coverage
• Update documentation: Update docs if needed

During Review

• Respond promptly: Address feedback in a timely manner
• Ask for clarification: If feedback is unclear, ask questions
• Be open to feedback: Consider suggestions objectively
• Explain decisions: If you disagree with feedback, explain why

Review Types on GitHub

Approval States

• Approve: The changes look good and can be merged
• Request Changes: The PR needs modifications before merging
• Comment: Provide feedback without explicit approval/rejection

Review Tools

• Line comments: Comment on specific lines of code
• General comments: Overall feedback on the PR
• Suggestions: Propose specific code changes
• File comments: Comments that apply to entire files

Setting Up Review Requirements

You can configure repositories to require reviews:

1. Go to repository Settings
2. Navigate to Branches
3. Add a branch protection rule
4. Require pull request reviews before merging
5. Set the number of required reviewers

Common Code Review Patterns

The Nitpick

Focus on style and minor issues. Use sparingly and consider automation instead.

The Teaching Moment

Use reviews to share knowledge and explain better approaches.

The Safety Check

Focus on security, performance, and correctness issues.

The Architecture Review

Discuss design decisions and architectural patterns.

Additional Resources