Code Review: benefits, best practices, tools, and tips

Code review is a fundamental process in software development that involves authors inviting other developers to provide feedback on their code before it's integrated into the main codebase. It's not just about catching bugs; it's a team effort to improve the code, share knowledge, and maintain coding standards.

Benefits of Code Review:

• Enhanced Code Quality: Code reviews play a vital role in improving the overall quality of the code. They pinpoint bugs, performance issues, security vulnerabilities, and other flaws early on in the development process.
• Knowledge Sharing: Through code reviews, team members can learn from one another, gaining deeper insights into the codebase and coding standards.
• Consistency: Code reviews ensure that coding standards and best practices are consistently applied throughout the project.
• Team Collaboration: Code reviews create a supportive atmosphere, enhancing teamwork and trust within the team.
• Continuous Improvement: By offering feedback and pinpointing areas for improvement, code reviews help developers enhance their coding skills and refine their practices.

Code Review Drawbacks:

• Time-Consuming: Code reviews can be time-consuming, especially for large codebases or complex projects.
• Development Delays: Code reviews might cause a bit of a delay in the development process since developers might have to wait for their code to be reviewed before moving forward.
• Feedback Overload: Code reviews might give developers a lot of feedback, which makes it challenging for them to handle.
• Reviewer Quality: The feedback and code review quality can vary depending on how much experience and knowledge the reviewers have.
• Resistance to Feedback: Developers may resist feedback or suggestions from reviewers, which could lead to conflicts and delays in progress.

Code Review Best Practices:

The code review process involves different perspectives: the code author, who asks for feedback, and the code reviewers, who look through the code change and provide feedback. While some best practices are specific to authors or reviewers, many benefit everyone on the team.

1. Things that Actually Matter:

To keep things friendly and productive during code reviews, it's helpful to have some guidelines in place. Here's what we suggest focusing on:

• Design: Is the code nicely designed and suitable for your system?Example: A reviewer might point out that a complex function could be broken down into smaller, more manageable functions for better readability and maintainability.
• Functionality: Does the code work as expected by the author? Does it benefit its users?Example: A reviewer might test the code with different inputs and scenarios to ensure it handles edge cases correctly.
• Complexity: Can the code be simplified? Will other developers find it easy to understand and utilize in the future?Example: A reviewer might suggest using a more efficient algorithm or data structure to improve the code's performance.
• Tests: Are there proper and well-constructed automated tests for the code?Example: A reviewer might point out missing test cases or suggest adding more comprehensive tests to cover different scenarios.
• Naming: Did the developer choose clear names for variables, classes, methods, etc.?Example: A reviewer might suggest renaming a variable from "x" to "userAge" for better clarity.
• Comments: Are the comments clear and useful?Example: A reviewer might suggest adding comments to explain the logic behind a complex section of code.
• Style: Does the code follow our style guides?Example: A reviewer might point out inconsistent indentation or spacing that violates the team's coding style guide.
• Documentation: Did the developer also update relevant documentation?Example: A reviewer might suggest updating the API documentation to reflect the changes made in the code.

It's best for developers not to spend their time reviewing things that can be automatically checked.

Example: Reviewing a function that calculates the total price of an order:

2. Discuss the High-Level Approach Early:

Before delving into coding a complex feature, it's good to chat about the big picture first. Usually, we do this when we're planning out the feature.

It's not very pleasant if a PR ends up needing a complete overhaul because we didn't discuss the approach beforehand. PR rewrites do happen every so often, but it's a hint that we should have a more thorough chat before diving in.

Sometimes, to get things rolling, we need a proof-of-concept. A great way to start is by opening a draft PR of the approach and making architectural decisions based on what we learn.

3. Use Code Review Checklists:

Using a code review checklist helps ensure consistency among all team members involved in coding or reviewing. It supports both seasoned developers and newcomers by providing guidance on best practices for their language or framework.

50% of the companies spend 2–5 hours weekly on code reviews. You can streamline this process with a checklist, and developers save time.

4. Keep Pull Requests Small:

Breaking down tasks into smaller batches makes them more manageable and efficient to handle. It's essential to consider not only the number of lines but also the number of files affected by the change.

Concentrating on smaller sections allows reviewers to thoroughly inspect all aspects (Consider using a code review checklist). With smaller PRs, developers can quickly understand code changes, and reviewers can give more focused and detailed feedback. This approach ensures that each change gets the attention it deserves and makes it easier to follow the style guide.

5. Foster a Positive Feedback Culture:

The code review process should be viewed as a chance for growth and knowledge exchange, rather than a critique of developers' capabilities.

For successful code reviews, it's crucial to establish a culture of collaboration and learning. Below is a list of suggestions for improving code review discussions:

• Always provide feedback on the code, not the author.
• Be open to the suggested changes.
• Inform those who benefit from this review.
• Admit that there are multiple correct solutions to every problem.
• Provide positive and helpful feedback.

This allows the development team to know the purpose behind code review and take it as a way to improve their coding abilities and skills.

6. Automate as Much as Possible:

Code review is important, but it takes time. Therefore, it is advisable to automate tasks that can be automated.

Use GitHub Actions to create a robust CI pipeline. Automated checks free up reviewers to focus on meaningful areas. It helps to improve code quality and increases the level of speed, accuracy, and consistency.

With GitHub Actions, developers can save time and avoid the frustration of having to manually check for quality. The action automatically collects and organizes all relevant tests, test coverage, code style checks, commit message standards, static analysis, and much more.

7. Be Less Nitpicky:

Your role as a reviewer is to help with fundamental issues like bugs, architectural problems, code design, or anything that affects maintainability. If you find yourself focusing too much on minor details, consider automating those checks to save time.

Many of the things that are criticized in code reviews can be detected using ESLint or Prettier rules to help identify issues like syntax errors, unused variables, formatting, and other common mistakes developers make. By automating these checks, we can free up time for code reviewers to focus on the bigger picture, such as code design, overall architecture, and test coverage.

8. Automate Review Requests:

When collaborating on large projects with multiple developers and numerous pull requests (PRs) are generated simultaneously, it can be challenging for reviewers to keep track of each PR. Sometimes, during the feedback cycle, reviewers may not know whether or not the author has made changes. In such situations, we need a mechanism to notify the code owner, ensuring that feedback changes are ready for review.

In these situations, using GitHub review requests is a friendly and helpful way to inform others that your code is prepared for review.

9. Read Your Own Changes:

Before submitting a pull request for review, it's best to carefully review the code changes. It's important to ensure that you've addressed any issues yourself before asking for feedback from others. This not only saves time for reviewers but also helps you catch any overlooked changes or problems that need to be fixed.

10. Document Code Review Decisions:

For a coder, having reliable documentation is really important. Good documentation helps us to understand the functionality of the code, promotes maintainability, and ensures smooth collaboration within our development team.

Documentation helps us to understand the purpose and intent of the code. Comments and README files make it easy for everyone to understand.

Well-documented code makes it easier to maintain. Clear explanations help to resolve problems quickly.

Documentation speeds up the development process. It helps us to quickly understand the code and make changes.

11. Create Clear PR Title and Description:

Providing a detailed title and description for the pull request (PR) helps reviewers quickly understand the changes.

12. Ask Open-Ended Questions:

Encourage an open dialogue during code review by asking questions that invite discussion and learning.

By following these best practices, development teams can maximize the benefits of code review, improving software quality, fostering learning and collaboration, and optimizing the overall development process.