Implementing a perfect software solution on the first try is impossible. At some point, developers may start suspecting their codebase is a complete mess and doesn’t correspond to what they had in their heads at the beginning of the project. It happens often and sometimes forces developers to make urgent code adjustments even before the product is launched, and users begin to find undetected bugs. As Fred Brooks wrote in The Mythical Man-Month, “The management question, therefore, is not whether to build a pilot system and throw it away. You will do that.” It’s not an action guide but rather a metaphor that nevertheless gives some clues about the state of affairs in the software development industry.

After the launch, the situation doesn’t usually improve in the long run. Technical debt, obsolescence of initially used technologies and techniques, and other factors make code changes unavoidable. Here, developers have multiple options for getting the job done, but the choice is often between rewriting the code from scratch and refactoring it. Both these approaches have their benefits and drawbacks that we’ll consider today.

Taking a Closer Look at Your Codebase

There are different signs that the source code of your project requires intervention. For example, maintenance may become pretty hard because developers can’t say what a specific piece of code does. Dealing with such a code may require too much effort and make developers feel overwhelmed even by the idea of dealing with it. If you decide that living this way is no longer an option and want to introduce some fundamental changes, you should start with code assessment. It will help you identify what specific issues require your attention.

Code analysis tools are software applications that can become pretty useful. They inspect and evaluate the source code and generate reports or metrics that indicate the code’s quality, performance, and complexity. Some analysis tools that can help with code refactoring are SonarQube, Code Climate, and ReSharper. Considering the pace of AI technology development and widespread adoption, it’s not a big surprise that there are a lot of AI/ML-powered code review tools. For example, CodeScene, DeepCode, Codacy, Reviewable, Snyk, and many others.

Technical debt and maintenance costs are the crucial factors signaling the need for quick changes. Technical debt refers to a situation when developers decide to postpone the implementation of technically complex solutions and choose a more straightforward path instead, which, over time, slows down development and makes code maintenance less convenient. In a way, it is similar to financial debt, where the cost of the debt increases over time if not repaid.

Read Also Technical Debt: Where Comes From and How to Manage It

The application’s inability to scale following increasing users is another major problem. More obvious signs include slow performance, lagging, and crashing of the app that you can detect via user feedback, which you, of course, carefully collect and analyze. Once all issues have been detected and analyzed, you can choose the optional way of introducing changes to the codebase.

Before choosing between code rewrite and refactoring, it’s essential to understand what they are and what they are not. If fixing defects, delivering new features, or cleaning up the UI are among your goals, you better consider product enhancement techniques rather than code refactoring or rewriting. The approaches we’re discussing today apply to a situation where the app does what it should do, but there’s an issue with how it does it. Here, we deal with non-functional or quality attributes of a software system. If users are happy with the app’s features but it crashes under peak loads and it’s hard for developers to work with the code, code rewrite or refactoring may become the solutions you’re looking for.

Code Rewrite. Tear It up and Throw It Away

Let’s start with something anyone with no coding experience can understand. When we say “rewriting,” we literally mean that you write the application code from a blank slate. Despite the apparent radicality of this method, it has its advantages and sometimes can feel like a relief since it frees developers from some limitations of the old codebase. In the case of legacy systems, some code parts may play significant roles, while the absence of proper documentation results in a poor understanding of how it actually works. Here, it’s easier for the software modernization team to rewrite the code thoroughly.

Read Also Busting Common Myths Regarding Legacy Software Modernization

When you need to rewrite the code, it doesn’t necessarily mean that the development team has failed or made some bad decisions. Even big and successful companies sometimes resort to this tactic. In 2017, the Uber company that revolutionized how people move from one point to another was on a rocket-ship growth trajectory. Yet, the company decided to rewrite Uber’s driver app to deal with technical debt, overcome product challenges, and align with engineering decisions made while rewriting the rider app in 2016. This code rewrite process is well-documented and considered super successful. However, it’s crucial to remember that when rewriting the code, you must freeze the implementation of new features since, in this case, you’ll be chasing a target that constantly moves. Not every business can afford not to pamper users with new features regularly.

Code rewrite is easy to understand but hard to implement. Creating the application code from scratch while preserving all its functionality requires two separate software development teams to maintain the old code and write the new one. Besides moving to new technology, developers may also move to more modern architecture, for example, shifting from a monolithic application to microservices.

Read Also Pros and Cons of Distributed and Centralized Architectures. Comparing Monolith, Microservices, and Distributed Monolith

However, rewriting doesn’t mean replacing all your code. That’s why you should start determining which code parts are still helpful and which ones need to go. Since you’ll have to rebuild certain application parts, you’ll need to create a new development plan, including project scoping, resource allocation, a clear understanding of the project goals and requirements, etc.

Continue reading to know what Code Refactoring is and see the tips of choosing the right option: https://xbsoftware.com/blog/code-rewrite-vs-code-refactoring/