Code Review Best Practices for High-Quality Software

A code review is a systematic examination of software code. It involves one or more software developers reviewing and evaluating the code written by a fellow developer before it's merged into the main codebase. To conduct effective code reviews that maximize these benefits, teams should follow certain best practices around process, mindset, automation, and human dynamics. This guide covers actionable recommendations on how to implement high-quality code reviews for better software.

Have a Clear Purpose

Code reviews should have a clear purpose beyond just "reviewing code". Well-defined goals help code reviewers provide valuable feedback efficiently. Some good purposes for code reviews include:

• Prevent bugs/errors: Reviewing code before it's merged can catch bugs, edge cases, errors, and regressions early. Reviewers can test the logic and spot potential issues. This prevents defects from impacting customers.
• Share knowledge: Reviewing each other's code is a great way for developers to learn. The author can explain their thinking, while reviewers share their expertise. Knowledge spreads throughout the team.
• Enforce standards: Code reviews help enforce consistent coding conventions and best practices. Reviewers can suggest improvements to bring code up to team standards. This improves maintainability.

Defining the motivations upfront prevents bike-shedding and focuses the conversation. Explicit goals keep code reviews productive and impactful.

Use Automated Tools

Automated tools like linters, pre-commit hooks, and formatters can help improve code quality and streamline the review process.

Linters

Linters analyze code for potential errors, bugs, stylistic errors, and suspicious usage. Running linters as part of your CI/CD pipeline can shift some basic quality checks out of code reviews. This enables reviewers to focus their efforts on more substantive issues.

Some popular linting tools include:

• ESLint for JavaScript
• Pylint for Python
• Rubocop for Ruby

Pre-commit Hooks

Pre-commit hooks automate checks or fixes during local development, before changes are committed. For example, you could run unit tests or auto-formatting with hooks. This helps authors find issues early and reduces back-and-forth in the review.

Tools like Prettier, Black, YAPF, and gofmt can auto-format different languages.

Formatters

Consistent code formatting eliminates whole classes of review comments. Formatting standards should be codified and enforced automatically.

Popular formatting tools include Prettier, Black, clang-format, gofmt, and more. Most IDEs and code editors can also auto-format code on save.

Automated tools lead to cleaner inbound code and speed up reviews. They complement human review rather than replacing it.

Involve the Right People

Code reviews should involve the author, reviewer, and maintainer when possible. This ensures that knowledge is shared between all parties involved in the code being reviewed.

The author provides context on the code changes and implementation decisions. The reviewer brings a fresh perspective to identify issues. The maintainer has insight into the overall architecture and future plans.

Including all three roles leads to more thorough reviews. The author benefits from the reviewer's suggestions. The maintainer gains awareness of recent changes. The reviewer sees the big picture and learns the reasoning behind the code.

Reviews limited to just the author and reviewer have gaps. The author lacks the maintainer's architectural knowledge. The reviewer has no background on the code's context. Involving the maintainer adds oversight and expertise.

Knowledge sharing is a key benefit of collaborative code reviews. The author explains their changes to the reviewer and maintainer. The maintainer shares the high-level design with the author and reviewer. The reviewer asks questions to learn from the author and maintainer.

Code quality is improved when all parties gain understanding through code reviews. Authors learn better practices from reviewers and maintainers. Reviewers develop skills from exposure to new techniques. Maintainers keep up with recent changes from developers.

In the end, code reviews are strengthened when authors, reviewers, and maintainers are engaged together. Reviews become a knowledge sharing exercise, benefiting everyone involved and leading to better code.

Provide Constructive Feedback

Code reviews provide an opportunity for team members to learn from each other and improve the overall quality of their code. However, giving feedback on someone's work can be challenging. Reviewers should strive to make their comments constructive, specific, and focused on solutions.

When providing feedback:

• Be kind. Focus comments on the code itself, not the coder. Use a polite, professional tone and avoid harshly worded criticisms.
• Be specific. Point to particular lines, variables, functions, etc. that should be changed. Vague comments like "this code is sloppy" are not helpful.
• Offer solutions. If you see an issue, suggest a way to fix it. Propose cleaner or more efficient alternatives.
• Justify suggestions. Explain the reasons for changes so the coder understands. Comments like "use a better name" should say what's unclear about the current name.
• Avoid nitpicking. Don't waste time on trivial formatting issues, like spacing or newlines. Focus feedback on substantive ways to improve code quality.
• Praise good coding practices. If something is done well, say so! Recognize solid structure, useful comments, good naming conventions, etc.
• Check your biases. Don't assume your coding style is the only right way. Be open-minded to alternative solutions.

Providing thoughtful, constructive feedback shows you care about improving the team's work. Just remember to deliver criticism with kindness, specifics, and solutions. This develops better code without hurting coder morale.

Discuss Complex Issues Separately

Code reviews should focus on small, incremental changes that are easy to review and understand. If major architectural changes or complex code refactors come up during the review, avoid blocking the pull request. Instead, have an offline conversation to thoroughly discuss the bigger picture issues. Usually software website review their project focusing on small ones and then going to bigger ones.

Schedule a separate meeting with the right stakeholders to debate large-scale changes. This could involve revising the requirements and goals for the feature, exploring alternative technical approaches, or planning a phased rollout. Taking the time to align on complex topics prevents frustrating back-and-forth debates during code review.

By keeping code reviews focused, reviewers can concentrate on improving the quality and correctness of each incremental change. Engaging in deep architectural discussions during a review can lead to frustration and bikeshedding. Having thorough offline conversations about complex issues leads to better solutions and helps avoid blocking progress.

Conclusion

Code reviews are an essential practice for producing high-quality software. By taking the time to thoroughly review code changes, development teams can reduce defects and technical debt while improving code health, knowledge sharing, and collaboration.

The benefits of well-executed code reviews are immense. Code quality improves, bugs are caught earlier, designs stay consistent, and teams develop better skills. Just as important, they enable knowledge sharing across the organization. By making code reviews a regular practice and following the best practices outlined, teams can reap these benefits and deliver higher-quality software.