php-rules

PHP Rules

These rules come from app/rules/php/ in ai-toolkit. They cover the project's standards for coding style, frameworks, patterns, security, and testing in PHP. Apply them when writing or reviewing PHP code.

PHP Coding Style

Standards

• Follow PSR-12 extended coding style.
• Use declare(strict_types=1) at the top of every file.
• Use PHP 8.1+ features: enums, fibers, readonly properties, intersection types.
• Use PHP CS Fixer or Pint for automated formatting.

Naming

• PascalCase: classes, interfaces, traits, enums.
• camelCase: methods, functions, variables.
• UPPER_SNAKE: class constants (public const MAX_RETRIES = 3).
• snake_case: not used for methods. PSR convention is camelCase.
• Suffix interfaces with Interface or prefix with contract name (project convention).

Type System

• Use typed properties: private readonly string $name;.
• Use union types: string|int. Use intersection types: Countable&Iterator.
• Use enum (PHP 8.1) for fixed sets of values. Use backed enums for persistence.
• Use readonly classes (PHP 8.2) for immutable DTOs.
• Use constructor promotion: public function __construct(private string $name).
• Use never return type for functions that throw or exit.

Functions

• Use typed parameters and return types on all functions/methods.
• Use named arguments for readability: new User(name: 'Ada', age: 36).
• Use null-safe operator: $user?->address?->city.
• Use match expression over switch for value mapping.
• Use first-class callable syntax: array_map($this->transform(...), $items).

Imports and Namespaces

• Use PSR-4 autoloading via Composer.
• Group use statements: classes, functions, constants.
• Never use require/include for class loading. Use Composer autoloader.
• Use one class per file. File name matches class name.

Error Handling

• Use exceptions for error conditions. Never return error codes.
• Create domain exception hierarchies extending RuntimeException or LogicException.
• Use match with throw for exhaustive error mapping.
• Log exceptions with context using PSR-3 logger.