php version guide

PHP 8.4 Changes

PHP 8.4 added property hooks, asymmetric property visibility, lazy objects, #[\Deprecated], request_parse_body(), and several standard-library improvements. Property hooks are powerful but should not hide surprising side effects.

Changes Worth Recognising

Property hooks attach controlled get or set behaviour to properties.
Asymmetric visibility can expose reads while limiting writes.
Lazy objects are mainly infrastructure for frameworks and libraries.
#[\Deprecated] lets APIs signal migration paths to callers.

Representative Code

PHP example

<?php

final class Product
{
    public private(set) string $sku;

    public function __construct(string $sku)
    {
        $this->sku = strtoupper($sku);
    }
}

echo (new Product('php-84'))->sku . PHP_EOL;

// Prints:
// PHP-84

Upgrade Review

Keep property hooks small and unsurprising.
Check reflection, serialisation, hydrators, and framework support before adopting hooks broadly.
Do not build lazy objects manually in ordinary application code without a concrete need.

Use PHP 8.4 features where they simplify a real model; do not turn every getter and setter into a hook merely because syntax exists.

Practice

Restrict a Public Write

Create a class with a publicly readable but privately writable identifier using asymmetric visibility. Set it in the constructor and prove external code can read it.

Show solution

Declare public private(set) string $id;, assign it from class scope, and read it from the created object. An external reassignment should fail.