What Is Code Review? 

A code review is a critical part of the software development process where the source code is systematically examined by one or more peers before it is merged into the main codebase. This practice aims to identify bugs, ensure coding standards are met, and improve the overall quality of the software. It’s a collaborative exercise that encourages sharing knowledge across the team, fosters learning, and enhances code maintainability.

Code review lies not just about identifying errors, but also about code optimization and adherence to coding conventions. This process enables developers to learn from each other and adopt best practices, leading to more efficient and reliable code. Moreover, it facilitates early detection of potential security vulnerabilities, significantly reducing the risk of security breaches post-deployment. 

Through constructive feedback, developers can refine their skills, contributing to the team’s overall expertise and the project’s success.

The Role of Code Review in CI/CD 

Code review is an important, if often overlooked, element in a Continuous Integration/Continuous Deployment (CI/CD) process. It acts as a quality gate that ensures only well-vetted and secure code is integrated into the main branch, supporting a rapid yet reliable release cycle. Code reviews ensure a level of quality that gives developers the confidence to automate many phases of the software delivery process.

Code review enhances collaboration and communication among team members. It allows for immediate feedback and iterations, making the development process more dynamic and responsive to change. Developers can address and rectify issues much faster, reducing the lead time for changes to be deployed. This continuous loop of feedback and improvement is crucial for maintaining high-quality standards in a fast-paced CI/CD environment.

Learn more in the detailed guide to CI/CD

Code Review Process Steps 

Here a structured process you can follow to implement code reviews in your organization:

1. Establishing Code Review Guidelines

Before diving into the review process, it’s crucial to establish clear code review guidelines. These guidelines serve as a roadmap for both reviewers and authors, ensuring that everyone is on the same page regarding what to look for and how to evaluate the code. 

Effective guidelines typically include criteria for code functionality, readability, and adherence to the project’s coding standards. They might also outline how to prioritize issues based on severity, from critical bugs to minor style violations. By setting these standards, teams can streamline the review process, making it more efficient and focused on areas that contribute most significantly to the project’s quality and maintainability.

In addition to technical aspects, guidelines should encourage a constructive and respectful feedback culture. This includes recommending language and tone that foster positive communication and growth. Guidelines might also suggest timeframes for review completion to ensure that the process does not become a bottleneck in the development workflow.

2. Reviewer Selection

Reviewers should have a good understanding of the project’s codebase and the technical expertise relevant to the code being reviewed. It’s often beneficial to include a mix of developers in the review process: those familiar with the specific subsystem or feature being changed and those with a broader perspective on the project. This diversity can lead to more comprehensive feedback, uncovering issues that might be missed by someone too close to the work.

Beyond technical skills, it’s important to consider the interpersonal dynamics of the team when selecting reviewers. Reviewers should be able to provide constructive feedback in a manner that is supportive and conducive to learning. In some cases, rotating the reviewer role among team members can help distribute knowledge and prevent any single individual from becoming a bottleneck.

3. Implementing Code Review Environment or Tools

The effectiveness of code reviews is significantly influenced by the choice of environment or tools used. 

Modern development workflows often leverage integrated development environments (IDEs) and code review platforms that facilitate the review process. These tools can highlight changes, facilitate inline comments, and support automated checks, making it easier for reviewers to provide precise feedback. Popular platforms like GitHub, GitLab, and Bitbucket offer built-in code review features that integrate seamlessly with version control systems.

Choosing the right tools can also enhance collaboration among team members who are not co-located. Features such as real-time notifications, threaded discussions, and the ability to suggest code changes directly can streamline the review process.

4. Code Inspection

The code inspection stage is where the core of the review takes place. Reviewers closely examine the code for issues related to functionality, security, performance, and adherence to coding standards. This involves not just looking for bugs but also assessing the code’s maintainability and scalability.

During this phase, reviewers might run the code, review unit tests, and check documentation to understand the changes fully. They look for code smells, potential optimization opportunities, and any deviations from the project’s coding conventions. 

It’s important for reviewers to approach this process with an open mind, considering the author’s intent and possible trade-offs they made. By focusing on significant issues that impact the project’s health and future development, reviewers can provide valuable insights that go beyond surface-level critiques.

5. Feedbacks and Comments

Providing feedback is a delicate art that requires balancing honesty with empathy. Effective feedback is specific, actionable, and focused on the code rather than the coder. Reviewers should clearly explain the reasons behind their comments, offering suggestions for improvement or asking clarifying questions.

Feedback should be organized and prioritized, distinguishing between mandatory changes and recommendations. Using a polite and respectful tone encourages a positive response and fosters a culture of continuous improvement. It’s also beneficial for reviewers to acknowledge what’s been done well, reinforcing good practices alongside identifying areas for improvement.

6. Final Approval and Merge

The final step in the code review process is the approval and merging of changes into the main codebase. This step usually requires at least one (or more, depending on the project’s rules) reviewer to formally approve the changes. 

Approval indicates that the code meets the project’s standards and is deemed ready for integration. However, if significant issues are identified during the review, the code may need to be revised and resubmitted for review, potentially undergoing multiple iterations.

Once approved, the code can be merged. This step should be accompanied by a clear commit message summarizing the changes and the review process. In some workflows, automated tests are run again post-merge to ensure that the new code does not break the build or introduce regressions.

Learn more in our detailed guide to code review checklist

Code reviews with Swimm

Code reviews are a hallmark of teams striving for high code quality and development best practices. However, They often create bottlenecks in the development process. The review process not only slows down the time it takes to ship code, it also often occupies some of the most talented and experienced developers on the team. Therefore, making code reviews more efficient can have a significant impact on a team’s velocity.

Swimm is an AI coding assistant that helps developers quickly understand large, complex codebases, while simultaneously capturing technical knowledge to fill in any documentation gaps. With Swimm, developers ask questions about their codebase and instantly get answers contextualized to their organizations codebase. 

Swimm can also be used to document Pull Requests, which helps streamline the review process and improve developer velocity. Once a PR is open, a document can be generated from it. Within seconds, AI will provide the developer with the context and reasoning behind the important changes in the PR, making the code review process faster and easier.

To try out Swimm, sign up for a 1:1 demo.