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| title | date | permalink | tags | cta | snippet | |
|---|---|---|---|---|---|---|
| Comments can lie. Code can't. | 2025-01-17 | daily/2025/01/17/lies |
|
~ | Comments in code can lie, but the code itself can't. |
How often have you need code like this?
// Returns true.
return false;
Whilst a comment like this could have been true when it was written, the code can change independently of the comment - making them out of sync and the comment no longer true.
As the comment is not evaluated or executed, there isn't a way to validate whether it's still correct, so whilst it could be, it may not be.
Comments should describe why the code is needed, not what it does.
If a comment describes the functionality, it can be refactored and extracted to a class, method or function - a.k.a. self-documenting code.
But, if you want something that will alert you if the functionality changes, look into automated testing.
If you have a passing test that suddenly starts to fail, you know the behaviour has changed.