The Comment Conundrum

In the world of software development, code comments are often touted as a way to clarify and document code. However, the reality is more nuanced. While comments can be useful, they often do more harm than good. Let’s dive into why this is the case and explore some practical examples to illustrate the point.

The Noise in the Code

Comments can quickly turn into noise within your codebase. When every line of code is accompanied by a comment, it becomes mentally taxing for developers to filter out the comments to focus on the actual code. This is particularly problematic because, over time, developers tend to ignore comments altogether to maintain their productivity[1][3][4].

Imagine reading a novel where every sentence is followed by an explanation of what the sentence means. It would be exhausting and would likely make you lose interest in the story. The same principle applies to code.

Commented Out Code: The Ultimate Sin

Commented out code is perhaps the most harmful type of comment. It serves no purpose other than to clutter the codebase and can lead to confusion. If the code is commented out, it’s likely because it’s no longer needed or it doesn’t work. In such cases, it’s better to delete it outright. Version control systems are there to keep track of past revisions, so there’s no need to keep commented out code lingering around[4].

graph TD A("Code Change") -->|Comment Out|B(Commented Out Code) B -->|Delete|C(Clean Codebase) C -->|Version Control|D(Historical Record) D -->|No Clutter| B("Efficient Development")

Confusing or Misleading Comments

Comments that contradict the code or are outdated can be more harmful than helpful. If a comment says one thing but the code does another, it can lead to confusion and errors. For instance, a comment might say “this function optimizes the algorithm” when, in reality, the function does something entirely different. This discrepancy can mislead other developers and even the original author when they revisit the code later[1][3].

The Myth of Helpful Comments

There’s a pervasive myth that comments are always beneficial because they provide additional context. However, this is not always true. Comments should only be used when the code cannot express the necessary information itself. For example, if a particular implementation is unconventional or has specific reasons for being that way, a comment can explain why. But if the comment simply restates what the code does, it’s redundant and unnecessary[3][4].

Public APIs and External Dependencies

One of the few legitimate uses of comments is in public APIs and when dealing with external dependencies. Here, comments can provide crucial information about how to use the API or why certain decisions were made. However, even in these cases, the comments should be minimal and focused on what the code cannot express[4].

Comment Therapy: A False Sense of Security

Some developers and managers believe that mandating comments for every function or block of code ensures clarity and maintainability. However, this approach can be counterproductive. It implies that the developers cannot write clear code on their own and need to patch over their deficiencies with comments. This not only insults the developers but also encourages them to write poorer code, knowing they can always add a comment to explain it[4].

The Boy Who Cried Wolf

When comments are overused, they lose their significance. Just like the boy who cried wolf, if every piece of code has a comment, the important warnings and explanations get ignored along with the noise. This makes it harder for developers to distinguish between critical comments and redundant ones[3].

Best Practices: When to Comment

So, when should you use comments? Here are some best practices:

  • Use comments sparingly: Only comment when the code cannot express the necessary information itself.
  • Avoid redundant comments: If the comment simply restates what the code does, it’s unnecessary.
  • Delete commented out code: It serves no purpose other than to clutter the codebase.
  • Keep comments up-to-date: Ensure that comments reflect the current state of the code.

By following these practices, you can ensure that your codebase remains clean, efficient, and easy to maintain.

Conclusion

Comments are not inherently bad, but they can be harmful if not used judiciously. The key is to strike a balance between clarity and brevity. By focusing on writing clear, self-explanatory code and using comments only when necessary, you can avoid the pitfalls of over-commenting and keep your codebase in top shape.

In the end, it’s about writing code that tells its own story, with comments serving as occasional footnotes rather than the main narrative. This approach not only makes your code more readable but also respects the intelligence and skill of your fellow developers. So, the next time you’re tempted to add a comment, ask yourself: “Is this comment really necessary, or is it just noise?”