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PHP 8.2 Released

PHP 8.2 is a major update of the PHP language.
It contains many new features, including readonly classes, null, false, and true as stand-alone types, deprecated dynamic properties, performance improvements and more.

Readonly classes

class BlogData
{
    public readonly string $title;

    public readonly Status $status;

    public function __construct(string $title, Status $status)
    {
        $this->title = $title;
        $this->status = $status;
    }
}
readonly class BlogData
{
    public string $title;

    public Status $status;

    public function __construct(string $title, Status $status)
    {
        $this->title = $title;
        $this->status = $status;
    }
}

Disjunctive Normal Form (DNF) Types

DNF types allow us to combine union and intersection types, following a strict rule: when combining union and intersection types, intersection types must be grouped with brackets.

class Foo {
    public function bar(mixed $entity) {
        if ((($entity instanceof A) && ($entity instanceof B)) || ($entity === null)) {
            return $entity;
        }

        throw new Exception('Invalid entity');
    }
}
class Foo {
    public function bar((A&B)|null $entity) {
        return $entity;
    }
}

Allow null, false, and true as stand-alone types

class Falsy
{
    public function almostFalse(): bool { /* ... */ *}

    public function almostTrue(): bool { /* ... */ *}

    public function almostNull(): string|null { /* ... */ *}
}
class Falsy
{
    public function alwaysFalse(): false { /* ... */ *}

    public function alwaysTrue(): true { /* ... */ *}

    public function alwaysNull(): null { /* ... */ *}
}

New "Random" extension

The "random" extension provides a new object-oriented API to random number generation. Instead of relying on a globally seeded random number generator (RNG) using the Mersenne Twister algorithm the object-oriented API provides several classes ("Engine"s) providing access to modern algorithms that store their state within objects to allow for multiple independent seedable sequences.

The \Random\Randomizer class provides a high level interface to use the engine's randomness to generate a random integer, to shuffle an array or string, to select random array keys and more.

use Random\Engine\Xoshiro256StarStar;
use Random\Randomizer;

$blueprintRng = new Xoshiro256StarStar(
    hash('sha256', "Example seed that is converted to a 256 Bit string via SHA-256", true)
);

$fibers = [];
for ($i = 0; $i < 8; $i++) {
    $fiberRng = clone $blueprintRng;
    // Xoshiro256**'s 'jump()' method moves the blueprint ahead 2**128 steps, as if calling
    // 'generate()' 2**128 times, giving the Fiber 2**128 unique values without needing to reseed.
    $blueprintRng->jump();

    $fibers[] = new Fiber(function () use ($fiberRng, $i): void {
        $randomizer = new Randomizer($fiberRng);

        echo "{$i}: " . $randomizer->getInt(0, 100), PHP_EOL;
    });
}

// The randomizer will use a CSPRNG by default.
$randomizer = new Randomizer();

// Even though the fibers execute in a random order, they will print the same value
// each time, because each has its own unique instance of the RNG.
$fibers = $randomizer->shuffleArray($fibers);
foreach ($fibers as $fiber) {
    $fiber->start();
}

Constants in traits

You cannot access the constant through the name of the trait, but, you can access the constant through the class that uses the trait.

trait Foo
{
    public const CONSTANT = 1;
}

class Bar
{
    use Foo;
}

var_dump(Bar::CONSTANT); // 1
var_dump(Foo::CONSTANT); // Error

Deprecate dynamic properties

The creation of dynamic properties is deprecated to help avoid mistakes and typos, unless the class opts in by using the #[\AllowDynamicProperties] attribute. stdClass allows dynamic properties.

Usage of the __get/__set magic methods is not affected by this change.

class User
{
    public $name;
}

$user = new User();
$user->last_name = 'Doe';

$user = new stdClass();
$user->last_name = 'Doe';
class User
{
    public $name;
}

$user = new User();
$user->last_name = 'Doe'; // Deprecated notice

$user = new stdClass();
$user->last_name = 'Doe'; // Still allowed

Deprecations and backward compatibility breaks