Code review is an important part of the software development lifecycle. It allows developers to improve code quality dramatically.

The process is like writing a book. The writer creates the story, but the editor reviews it, so there aren't any errors, like confusing "you're" with "yours". In this case, code review is the act of reading and evaluating other people's code. The purpose is to find areas of improvement or bugs at an early stage that might otherwise go unnoticed. The code review processes typically happens before merging with the codebase.

We will now discuss the benefits of code review and how to do it properly. And remember, when creating software, it's important to do code reviews, whether for small or large projects.

Table of contents

Why is Code Review important?
Benefits of Code Review
When and who does review processes
Where should code review be done?
What are the code review best practices?
How to conduct Review Processes?
The Agile Case
Code review saves your company money
Why should you hire someone to do code reviews?

Why is Code Review important?

Any software product, website, or mobile app, consists of code. The more consistent this code is, the more convenient it will be to work with it, for instance, if there's a need to change the project.

A perfect code should be easy to understand, flexible to modify, and readable. But since the work develops quickly, it may overlook these factors. That's why code reviews procedures are necessary to improve its quality.

As a result, code review accelerates and streamlines the software development process.

Benefits of Code Review

1. Ensures consistency in design and implementation

Every developer has a unique programming style. If developers continue to use their coding style, this hinders collaboration and delays progress. Code review forces developers to follow specific coding practices. Using this approach, all developers (including new ones) will understand the source code more easily.

Code review is also valuable as team members change throughout a project in the long run. Maintaining a consistent coding pattern will also enable future developers to spend less time analyzing the existing code and instead build new features.

2. Optimizing code for better performance

Even the most experienced developers can overlook mistakes in programming due to its monotonous nature. By inviting a fresh set of eyes to review the code units, code review helps cut errors before moving on.

3. Collaborating and sharing new techniques

Generally, developers work alone, and it’s easy to make some mistakes. With our code audit service, there is an opportunity to learn better techniques to write code and, possibly, learn how to do it better. This way, developers can upgrade their skills by learning about the latest technologies.

4. Tracking project requirements and quality

Projects have clearly defined scopes and requirements. But some unnecessary things can happen when a project involves several developers. Imaginary Cloud works closely with Project Managers to ensure that processes align with client needs.

Code review manages scenarios by comparing development to expectations. It validates developed features. Doing so quickly resolves any misinterpretation of the scope or requirements. It also helps ensure to don't miss critical features.

Although code reviews seem like another routine check, they do much more than that. Code reviews improve collaboration, learning, timely verification, and streamlined development.

When and who does review processes

Code reviews occur after all automation checks and before the working branch merges with the main branch (source code).

In the code review process, at least two roles are present. Those who write code and create Pull Requests are "authors," and those who examine the code are "reviewers." The reviewer and the author can elaborate in more depth with the following diagram:

Code Review Cycle.
Code review cycle

Where should code review be done?

The process can happen in many places, like developers' machines, online platforms, etc. The following points explain the best practices for review processes.

  • Over-the-shoulder: Over-the-shoulder code reviews happen at a developer's desk, where an experienced team member walks through the new code and makes suggestions. This approach is the easiest to use and does not need predefined structures.

  • E-mail pass-around: The code is sent by e-mail once it is ready. Although e-mails offer a more passive approach to code review, content can become nested in multiple replies and difficult to manage and search. Further, it can be challenging to determine when to finish the review.

  • Pair programming: Using this method, many developers can be present at the workstation, but only one writes code, and the other provides real-time feedback and suggestions.

While it may serve as a helpful tool for teams to inspect the code and train developers, it could prove inefficient due to its time-consuming nature. This process locks the reviewer from doing any other productive work during the period.

  • Tool-assisted: A tool-assisted code review process makes code review easier. It could be open source or paid, like GitHub, BitBucket, etc. Today, most people prefer it. It generally helps with:

    • Organizing and displaying the updated files.
    • Providing a communication channel between reviewers and developers.
    • Measuring the effectiveness of the code review process.

What are the code review best practices?

1. Create code reviews checklist

The code review checklist is a structured method for ensuring code excellence before accepting it. Some of the items are:

  • Functionality: Does the code behave as the PR/MR author likely intended? Does the code behave as users would expect?
  • Readability: Code should be self-explanatory. Use appropriate names for variables, functions, and classes.
  • Security: Does the code expose the system to cyber-attacks? Is more testing necessary?
  • Architecture: Is the code well-designed and fitted to the surrounding architecture?
  • Reusability: Does the code use reusable components, functions, and services? For some things, such as structure and logic, you can automate checks (e.g., static analysis).
  • Tests: Does the PR/MR have correct and well-designed automated tests?
  • Comments: Are the comments clear and useful?

Others, such as design and functionality, require human review. Reviewing code with certain questions can help you focus on the right things. For instance, you might test code to answer:

  • Is it clear what the code does?
  • Does it perform as expected?
  • Does this code fulfill regulatory requirements?

When you look at code critically, you will ensure you check for the right things with questions in mind. It reduces testing time.

2. Introduce code review metrics

Without metrics, you can't correct the code quality. Measurement of objective metrics improves your reviews, assesses the impact of process changes, and predicts the time to complete a task. Some commonly used review metrics include:

  • Inspection rate: The rate at which your team reviews a specific amount of code, calculated by dividing lines of code by the number of inspection hours. There may be readability issues if it takes a long time to review the code.

  • Defect rate: The frequency of identifying a defect divided by the inspection time. The metric helps you determine the effectiveness of your testing procedures. For instance, if your developer is slow to find bugs, you may need better testing tools.

  • Defect density: You can calculate it by dividing the defect count by thousands of lines of code. You can then allocate more resources to the most vulnerable components. Suppose one of your web apps has significantly more defects than others in the project. More experienced developers may be required to work on it.

3. Keep your code reviews under 60 minutes.

Reviewing code for longer than 60 minutes is not recommended. The performance and attention to detail begin to drop after that point. It's best to conduct code reviews frequently (in short sessions) so the breaks allow your brain to recharge. Then, you can review it again with fresh eyes. Frequent reviews will help you improve the codebase quality.

4. Limit your checks to 400 lines per day.

Trying to review a lot of code at once makes it harder to find defects. Keep code reviews to 400 lines or less each. Lines-of-code limits are equally important as time limits. It helps you maintain the best codebase.

5. Provide Helpful Feedback

Instead of being critical, try to be constructive. It's easier to do this by asking questions instead of making statements. Make sure to give constructive feedback as well as praise. Giving feedback in person (or even doing your review) will help you communicate with the right tone. Reviewing is a learning experience that benefits all involved.

How to conduct Review Processes?

If you decide to run a code review by yourself or internally, you should follow these steps:

  • Know what you're looking for in a code review.
  • Understand the different ways to conduct a code review.
  • Hold regular group meetings where participants can receive feedback on their particular areas while also receiving notes about any issues.
  • Make comments clear and specific.
  • Be open to improvement.
  • Be available for discussions.
  • Start with small changes, then review more complex ones.
  • Keep the status of a commit updated.

The Agile Case

In an Agile environment, it is possible to conduct code reviews seamlessly.

The premise is to adapt to changing requirements, respond to user needs faster, streamline processes, shorten development iterations, and enable higher productivity. It involves continuous attention to technical excellence and the ability to respond to change while maintaining a high level of quality.

Apple and Google are known Agile companies, and the quality of their products reflects this additional effort.

The methods mentioned above for code reviews are an example of Agile processes. They are less expensive and effective in minimizing bugs and improving the quality of the source code.

Code review saves your company money

A code review allows you to fix bugs, ensure compliance and confirm the application meets specs before completion – when it would be more expensive to make those changes.

To see where code reviews' time- and cost savings come from, you need to look at the process differently. Catching errors and bugs and fixing them quickly means they won't cause problems in the next development phase. If you don't catch them immediately, the time and costs involved in rework can multiply. IBM's Systems Sciences Institute reports that fixing bugs at implementation costs five times more than during design and architecture.
Further, fixes at the integration testing phase can cost ten times more during beta testing, fifteen times more, and thirty times more after release.

Why should you hire someone to do code reviews?

While in this article, we discuss how to conduct a code review, more often than not when dealing with more complex projects, this can consume a lot of time and resources.

For this reason, outsourcing code review might be a wise move as:

  • Someone with a fresh perspective should review the code.
  • Developers involved in the project can continue to work on it and add features or progress, which saves valuable time.
  • Efficient use of resources (use in-house experts in other functions where they are most needed).
  • These companies have already developed well-established methods, making the process more efficient.

As we can see, this service offers several advantages. For this reason, Imaginary Cloud performs code audits because we want to simplify people's lives.

Imaginary Cloud code audit