August 30, 2023

What Is a Code Review? + How to Do Code Reviews at Scale

Code Review
Version Control

Code review: it is an essential step in the development process for many businesses. Software developers often have a love/hate relationship with code reviews. Generally, the organizations that implement code reviews agree that they save time in the long run by catching issues and inefficiencies early. 

In this blog, get an overview of what a code review is, the challenges involved with them, and the purpose of code review. Plus, learn how to do code reviews at scale. 

Read long or jump ahead to the section that interests you most.

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What Is a Code Review? 

A code review is the process of examining code for quality. One or more developers who weren’t involved in authoring the changed code will review code changes to identify potential errors and suggest improvements. This can happen before or after the code changes are committed to the existing codebase. 

Why Are Code Reviews Important? 

Code reviews are important because they improve the quality and security of code, as well as the efficiency of the team developing it. 

Code reviews are a critical step in the development process for many teams. They improve a product’s quality by letting teams find and fix issues as early as possible. They ensure the consistency and reliability of code. And they help cross-train and align the development team on how the product is built and the standards they are expected to maintain. 

For those reasons, code reviews improve a team’s efficiency over time — even if they can feel time-consuming in the present! 

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What Do Developers Look at in a Code Review? 

The purpose of a code review is to improve the quality, security, and maintainability of a codebase. For that reason, these are some elements developers typically assess when doing code reviews: 

  • Functionality — Does it perform its intended task correctly and meet the specified requirements? 
  • Design — Does it align with the codebase’s existing architecture? Does it align with best practices your team follows? 
  • Readability and clarity — Is the code easy to follow? Does it have clear variable names? 
  • Maintainability — How easy will the code be to maintain and modify in the future? 
  • Security Does the code remove or add any vulnerabilities to the product? 
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How to Do Code Reviews: The Basic Steps 

There isn’t a one-size-fits-all approach to code review. There are different models for code reviews depending on when it is done in the lifecycle of changes in the product.  

For example, you could do a code review before code is committed to a shared repository. These are known as “pre-commit” code reviews. Or you could instead choose to do a code review after code is committed. These are known as “post-commit” code reviews. Sometimes development teams will mix both pre-commit and post-commit code reviews in a single project. For example, repositories requiring more checks and balances typically use a pre-commit review, whereas code in the early prototyping stages of a product may prefer to use a post-commit review process. 

Even though there are many ways to perform code reviews, here are some basic steps many teams follow: 

  1. Get context. Review the specifications for the code and understand why it is being created or changed. 
  1. Set it up. [Optional] Run a build containing the proposed (pre-commit) changes or the already submitted (post-commit) changes.  
  1. Review. Assess the code for the previously mentioned factors — functionality, design, clarity, and maintainability. Since code reviews are often a collaborative process, you may want to use a code review tool (more on those later). Takes notes and make comments. Remember to be constructive and helpful. 
  1. Get changes approved and merge it. If doing pre-commit reviews, once all feedback has been addressed and issues resolved, the new code can be merged into the main codebase.  

Using Multiple Repository Types? 

Cross-functional teams use Helix TeamHubto collaborate better, even when using multiple repository types, from Git to Mercurial to SVN. 


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Top Code Review Challenges 

In addition to ironing out a process that works the best for your team, there can be many challenges to doing code reviews. Some of these challenges include: 


Code reviews for a small team and project might be straightforward. It can be as easy as simply asking a colleague to take a look at what you have written and give you a few verbal comments.  

But as the team, number of projects, and number of changes grow, there are challenges to doing good code reviews at scale. It can be hard to balance quality, consistency, and speed.  

Scale is not only about the number of people on your team. It’s also about how many projects and branches there are.  

Distributed Teams 

With distributed and remote teams, it can become very challenging to stay on top of what has been reviewed. This will become a big source of wasted time without appropriate tooling.  

Cost of Mistakes 

Code reviews can present different challenges based on what you’re building. For instance, in chip design, you have tape-out dates (the final phase of the design lifecycle). In this situation, mistakes can be extremely expensive and must be avoided at all costs. 

Variant Management 

Another complexity at scale is variant management. The more variants your product has, the more complex the code review process risks becoming. Working with all of this at-scale can be a challenge. 


Another challenge is establishing traceability. How can you prove what has been reviewed and by who? How do you track the decisions that resulted in a certain solution? This can be extremely important in patent rights discussions in regulated industries. Traceability is also important for identifying the source of new issues. 


If you’re in a regulated industry like automotive, standards may define how code reviews should be done. Obviously, not following a regulation is not an option. But you might be able to find more efficient ways to comply than what your competitors do via a more efficient code review process.  


Being Agile at scale can be difficult, but ensuring that the code review process is something that is speeding up rather than burdening the organization is essential.  

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How to Do Code Reviews at Scale  

The larger your teams are, and the more complicated your projects are, the more considerations there are when establishing a code review process. Here are some tips for how to do code reviews at scale. 


1. Choose the Right Tool 

It’s important to choose the right code review tool for your team.  

The right tool: 

  • Doesn’t keep your colleagues waiting. 
  • Gives you visibility into what’s going on. 
  • Automates via workflows and integrations into other DevOps tools (version control, build automation, etc.) 
  • Delivers feedback and automated notifications. 

All of this is critical to overcome the challenges of doing code review at scale. 

Helix Swarm, for instance, is the code review tool for Perforce Helix Core. It does all of the above and helps your team work as efficiently as possible.  

2. Remember Reviewing Code is a Skill 

Communication is critical in code reviews. It’s important to give clear feedback during code reviews to improve the overall quality of your product. It is also important to remember that the feedback should be directed at critiquing the code, not the author of the code.   

It’s also important that the team stays in the loop — and that you have visibility — throughout the process. This can be difficult when you deal with different time zones, especially as the trend for remote work continues to grow. Being able to communicate clearly your review feedback is key to working efficiently. 

Treat reviewing code as a skill. This is something your teams can be good or bad at. Invest in training the team to improve their feedback and review skills. 

Using Helix Swarm will help your team members communicate, collaborate, and improve — even if everyone works from a different location. 

3. Maintain a Single Source of Truth 

Maintaining a single source of truth is just as important in code reviews as it is in version control 

You need to have a global review system that scales — and keeps everyone reviewing the most recent changes to the code. If you don’t, it’s much harder to get a big picture — especially if you’re working with teams of hundreds or thousands of people. When a change is ready to be reviewed, you want that to happen as quickly as possible.  

With Helix Swarm, you’ll be able to work effectively locally and scale globally. You will get visibility into what people are doing. And your team will be able to work quickly to commit changes. 

4. Integrate Your Toolset 

Integrating your toolset is essential for doing code reviews at scale for DevOps. After all, code review and version control aren’t the only tools you’ll be using. 

For example, you might be using Jenkins as yourbuild runner. Jenkins can be integrated with Helix Swarm and Helix Core to ensure an efficient workflow for CI/CD.  

In the case of a pre-commit review, a team member submits their code for review. Once Jenkins (or whichever build runner tool the team uses) reports that the build and tests have passed, Swarm notifies the team that changes are waiting to be reviewed and approved. Once approved, the code can be committed automatically.  

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How to Make Good Code Reviews Better With Helix Swarm 

You can make good code reviews even better by using Helix Swarm 

By using Helix Swarm, you’ll be able to conquer the code review challenges of: 

  • Scale. 
  • Distributed teams. 
  • Cost of mistakes. 
  • Variant management. 
  • Traceability. 
  • Regulations. 
  • Agility. 

Your team will be able to communicate better. You will get a single source of truth. And Helix Swarm is built for use alongside Helix Core. It integrates with Jenkins, Jira, and many other tools to make your code review workflows flow smoothly.  

Ready to review code, collaborate faster, automate workflows, and monitor progress? Get started with Helix Swarm today. 

Already Using Helix Core?  

You can download Helix Swarm and use it for free. 

Not Using Helix Core Yet?  

Helix Core is the industry standard version control system for teams who need to innovate at scale. You can use the full version completely free for up to 5 users.  


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