attac-t Skill: Type Safety
"Strong type systems allow developers to have much more insight into the program when writing the code, instead of having to run it."
The Standard
- Types Are Documentation: A signature tells you what's expected.
- Fail at Compile Time: PHP 8+ gives us tools. Use them.
- DTOs Over Arrays: Named fields over string keys.
- IDE as Partner: If your IDE can't autocomplete, neither can your brain.
The Check
Ask yourself:
- Can my IDE autocomplete this?
- Would a typo in a key cause a runtime error?
- Does the function signature tell me what it expects?
- Am I relying on documentation that might be stale?
The Protocol
- Type Everything: Return types, parameters, properties.
- Avoid Mixed: If you write
mixed, you've given up. - Strict Mode:
declare(strict_types=1);in every file. - Static Analysis: Run PHPStan/Psalm. Trust the warnings.
Real-World Examples
See examples.md.