The Evolution of Code Reviews: The Beginnings
Tags: programming, devops, productivity, github
Published: 2023-07-12 17:00:00

Code review is now a vital part of software development in the age of DevOps. Understand the evolution of code review from its early days to its present shape. We'll look at how code review has adjusted to the demands of development teams, from time-consuming manual reviews to efficient automated ones.

With the rise of DevOps, the code review process has become a substantial part of software development. The right code review process ensures that our applications are highly available and can be built with high velocity.

Over the years, code review has evolved from manual processes to automated tools, adapting to the changing needs of development teams. As application development continues to evolve, it's essential for code review to keep pace and provide teams with the best possible workflow for ensuring code quality.

In this 2 part series, we will explore the evolution of code review from its early days to its current state. We'll look at how code review has adapted to the needs of development teams, the trends driving its evolution, and the future of code review.

In this first part, we will go through the pages of history to understand how the code review process came into existence, and how some of the shortcomings led to major disruptions.

Whether you're a team leader trying to set the right practices for your development team, just a seasoned developer or simply starting in the software development world, this series will provide valuable insights into the importance of code review. Join us on a journey through the evolution of code review, and discover how it continues to shape the future of application development.

## The Dark Ages

In the early days of software development, code review was a manual process. Developers would physically sit down together and review the code line by line, discussing any issues or suggestions. While this method was effective, it was also time-consuming and not scalable for large development teams.


![code review evolution meme](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/tynxcfpcaerpvxlrbjvt.png)

The  [introduction of Git in 2005](https://www.welcometothejungle.com/en/articles/btc-history-git) revolutionized how software development teams worked. It scaled the way teams, and contributors could now collaborate as developers could submit their code changes as pull requests. These pull requests would then be discussed and reviewed by other team members and, once accepted, were automatically merged into the main codebase. This was the rise of version control and all its benefits, such as keeping a history of changes and being able to roll back to previous versions.

However, this method relied on manual reviews, and the feedback process was often slow and inconsistent. With Git, teams had the flexibility to conduct code reviews in any way they saw fit, which led to inconsistencies in how code was reviewed. Different teams used different processes and tools, and the process of manually checking the pull request still made it difficult to standardize the entire code review process.

Overall the code review process was very manual and slow. Cutting corners to get functionality out to production often meant disruptions and bugs.

## When Disaster Hit

This is exactly what happened to the [London Stock Exchange on February 8th, 2008](https://www.nytimes.com/2008/09/08/business/worldbusiness/08iht-lse.4.15984073.html). It's usually not the best time for a financial institution facilitating trade in Europe's financial hub to be down in the middle of a global recession. This disruption was caused due to a bug in the new trading system that was released then.

The impact was that trading came to a halt for almost an entire day, and till today the financial amount lost due to the impact is not publicly available. It is safe to say, though, there are significant losses for the Exchange and its customers. Given the scale of the incident and the impact, it had on the financial markets.

Another such example is that of [Knight Capital Group's trading systems](https://www.henricodolfing.com/2019/06/project-failure-case-study-knight-capital.html) which experienced an incident that led to a significant financial loss of $440 million in just 45 minutes. The issue was due to a code change that was not properly reviewed and tested, underscoring the significance of a comprehensive and efficient code review process.

## Conclusion

The code review process has become an integral part of software development with the rise of DevOps. Over the years, code review has evolved from manual processes to incorporating automation. This was due to the need to push changes faster while maintaining the stability of your systems.

However, meeting this requirement was something that was just not feasible with the way code reviews were being performed. Stress the system too much and you could have experienced great outages and disruptions such as that of the London Stock Exchange or…

By tracking the evolution of code reviews and being aware of the past issues, we know it is important for us to refine our coe review process. How we can do so is answered in [part 2](/blog/the-evolution-of-code-reviews-a-better-tomorrow) of this series where we continue our evolution into the future!

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