php-8.2

PHP 8.2 Features and Best Practices

Overview

PHP 8.2 continues the language's evolution with new features, deprecations, and performance improvements. This document outlines the key features introduced in PHP 8.2 and provides best practices for their implementation.

Key Language Features

Readonly Classes

PHP 8.2 introduces readonly classes, which automatically make all declared properties readonly without having to declare each property individually as readonly.

readonly class User {
    public function __construct(
        public string $id,
        public string $name,
        public string $email
    ) {}
}

$user = new User('1', 'John', '[email protected]');
// $user->name = 'Jane'; // This would trigger an error

Best Practices:

• Use readonly classes for immutable value objects and DTOs
• Combines well with constructor property promotion for concise code
• Great for entities where you want to ensure data integrity
• Remember that readonly applies to properties but not to methods
• Consider using readonly classes instead of creating getters for all properties

Disjunctive Normal Form (DNF) Types

PHP 8.2 supports Disjunctive Normal Form types, allowing more complex type expressions by combining union and intersection types.

function process(
    (Countable&Iterator)|array|Traversable $collection
): (int&Stringable)|string {
    // Process collection
}

Best Practices:

• Use for complex type constraints that need both union and intersection types
• Parentheses clarify the type hierarchy and grouping
• Keep type expressions as simple as possible for readability
• Document complex type requirements thoroughly
• Consider if a complex type might be better represented by an interface

Allow null and false as Stand-alone Types

PHP 8.2 allows using null and false as standalone types, not just in union types.

function alwaysReturnsNull(): null {
    return null;
}

function processBooleanResult(): false|int {
    // Return false for failure or an integer for success
}