On November 23, 2023, PHP 8.3 is set to launch, featuring enhancements to readonly classes, the introduction of the json_validate() function, expansions to the recently incorporated Randomizer class, stack overflow detection, and various other improvements.

Readonly improvements

This Request for Comments (RFC) suggested two modifications, but only one gained approval: the ability to reinitialize readonly properties during cloning. While this might seem significant, it’s essential to note that this RFC specifically targets a narrow, yet crucial, scenario – the alteration of property values within __clone() to facilitate the deep cloning of readonly properties.

class PHP {
    public string $version = '8.2';
}

readonly class Foo {
    public function __construct(
        public PHP $php
    ) {}

    public function __clone(): void {
        $this->php = clone $this->php;
    }
}

$instance = new Foo(new PHP());
$cloned = clone $instance;

// For PHP<8.3 Fatal error: Cannot modify readonly property Foo::$php
// With PHP 8.3 this is now possible!!
$cloned->php->version = '8.3';

[RFC] Class constants with explicit types

It is now possible to provide type hints for class constants:

class Foo
{
    const string BAR = 'PHP8.3'; 
} 

[RFC] Introduced #[\Override] attribute

The recently introduced #[Override] attribute serves as a declaration of the programmer’s intent. Essentially, it communicates, “I am aware that this method is overriding a parent method. If this ever changes, kindly bring it to my attention.”

abstract class Foo
{
    public function someMethod(): string
    {
        return 'PHP8.2';
    }
}

final class Bar extends Foo
{
    #[Override]
    public function someMethod(): string
    {
        return 'PHP8.2'; // The overridden method
    }
} 

[RFC] Recently added function, json_validate()

Before, the sole method to validate if a string constituted valid JSON was to decode it and check for any resulting errors. The newly introduced json_validate() function proves advantageous when you solely need to determine the validity of the input as JSON, as it consumes less memory than decoding the string.

var_dump(json_validate('{ "test": { "foo": "bar" } }')); // true

[RFC] Additions to the Randomizer

In PHP 8.2, the introduction of the new Randomizer class comes with a few minor additions:

Randomizer::getBytesFromString(string $string, int $length): string

This function enables the creation of a string with a specified length, comprising randomly chosen bytes from a given input string.

$randomizer = new \Random\Randomizer();

$temperature = $randomizer->getFloat(
    -89.2,
    56.7,
    \Random\IntervalBoundary::ClosedOpen,
);

The getFloat() function produces a float value within the range of $min and $max. You can specify whether the boundaries, $min and $max, are inclusive using the IntervalBoundary enum. A setting of “Closed” includes the value, whereas “Open” excludes it.

Fetching dynamic class constants

In PHP 8.3, you can retrieve constants using a more dynamic syntax:

class Foo {
    const PHP = 'PHP 8.3';
}

$searchableConstant = 'PHP';

var_dump(Foo::{$searchableConstant});

Related reads:

What’s new in PHP 8.2