The Imperative of Code Comments in Non-Trivial Projects

Introduction

When developers are asked if they need to comment their code, the debate often revolves around the concept of ldquo;self-documentingrdquo; code. While it is true that well-written code with clear structure can be self-explanatory, it is not always sufficient, especially in larger and more complex projects. This article will explore the necessity of code comments in both short and long-term projects and address common myths and practices in corporate software environments.

Why Code Comments Are Necessary

For large amounts of code, particularly in non-trivial projects, documentation is crucial. Despite developers’ best efforts, the need for documentation cannot be overstated. Code comments help to explain architectural concepts and design decisions that make complex systems easier to understand. This is especially important in production systems, such as those used in banks and insurance companies, where code can remain unchanged for decades.

Consider a 20-line block of code in a production system. Without comments, identifying the purpose and functionality of this code becomes extremely difficult. After 2 months, a developer is less likely to remember the exact purpose, and new developers who join the project will face the same challenge. Therefore, commenting is a necessity to ensure readability and maintainability in long-term codebases.

The Challenge of Long-Term Projects

Code in large-scale production systems tends to be less refactorable due to various corporate and managerial factors. Here are some factors that contribute to this:

Under political and hierarchical pressures, mid-level managers and executives often avoid refactoring existing code, as it does not contribute significantly to their promotions or bonuses. Breaking existing functionality is not viewed favorably, and bugs and new features take precedence over refactoring.

Many organizations choose to use manual management tools due to a lack of understanding and the time and effort required to transition to more sophisticated source code and version management systems. Legacy tools like SVN are preferred over modern alternatives due to their lower learning curve and cost.

Senior developers in corporate environments may have more experience in managing their managerial roles rather than focusing on technical practices like unit testing. Consequently, these practices are often not implemented, and legacy code remains uncommented and difficult to maintain.

These factors create a culture where code comments are essential to keep the project understandable and maintainable over time.

Best Practices for Implementing Code Comments

To ensure that code comments are effective, follow these guidelines:

For every 20 to 30 lines of code that convey a complex concept, ensure that the comments are specific enough to explain why certain decisions were made rather than simply describing what the code does.

Comment blocks of code rather than individual lines. This helps in providing a clear overview of the purpose and functionality of the block.

As changes are made to the code, ensure that the comments also reflect these changes. Old comments can be misleading and create confusion for future developers.

By adhering to these practices, developers can ensure that the code remains maintainable, even in the face of political and managerial obstacles.

Conclusion

While self-documenting code is an excellent goal, it is not always sufficient, particularly in non-trivial projects and large-scale production systems. Code comments are crucial for explaining complex concepts and ensuring that the code remains understandable and maintainable over time. Developers should take the time to comment effectively and keep the codebase clear and concise.