32 lines
1 KiB
Markdown
32 lines
1 KiB
Markdown
---
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title: Comments can lie. Code can't.
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date: 2025-01-17
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permalink: daily/2025/01/17/lies
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tags:
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- software-development
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cta: ~
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snippet: |
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Comments in code can lie, but the code itself can't.
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---
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How often have you need code like this?
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```php
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// Returns true.
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return false;
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```
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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.
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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.
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Comments should describe why the code is needed, not what it does.
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If a comment describes the functionality, it can be refactored and extracted to a class, method or function - a.k.a. self-documenting code.
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But, if you want something that will alert you if the functionality changes, look into [automated testing][0].
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If you have a passing test that suddenly starts to fail, you know the behaviour has changed.
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[0]: {{site.url}}/atdc
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