WHat's new in PHP 8.2

MergePHP December 2022

Ian Littman

@ian@phpc.social / @iansltx

https://ian.im/php82merge

It's Live!

Thanks to release managers Ben Ramsey, Pierrick Charron, and Sergey Panteleev

What we'll cover

Where to get it now
What's new
What's deprecated/removed
How to find out more information

How do I get it?

macOS

```
brew tap shivammathur/php
```
```
brew install php@8.2
```

Ubuntu/Debian instructions (aka use Ondrej's repo)
Red Hat-based: use Remi's repo
Inside Docker: e.g. php:8.2.0-fpm-alpine3.17
Windows builds can be downloaded here
Source code to build yourself is on php.net

New Features

Before

class Post
{

    public readonly string $title;
    public readonly Status $status;

    // snip
}

After

readonly class Post
{

    public string $title;
    public Status $status;

    // snip
}

Readonly Classes

This also disables dynamic properties and untyped properties (use "mixed")

Type improvements

Disjunctive Normal Form (DNF) types
- (A&B)|C -> Must be both A and B, or C; builds on:
  - A&B -> Must implement/extend/be both A and B (PHP 8.1)
  - A|C -> Must be either A or C (PHP 8.0)
- Parentheses required when OR'ing AND'd types
- One layer of nesting; (A&(B|C)) is not valid
- Only intersections in parentheses: A&(B|D) is not valid
New standalone types
- null and false
- true
- Powerful when combined with union or DNF types

Random extension

random_* functions, plus e.g. rand/srand/mt_rand, now live in this extension

New Random\Randomizer class

Takes a Random\Engine impl (default "Secure")
```
nextInt(): int
```
```
getInt(int $min, int $max): int
```
```
getBytes(int $length): string
```
```
shuffleArray(array $array): array
```
```
shuffleBytes(string $bytes): string
```

pickArrayKeys(array $array, int $num): array

```
__serialize()/__unserialize()
```

Random Engines

namespace Random;

interface Engine {
    public function generate(): string;
}

interface CryptoSafeEngine extends Engine {}

Non-crypto-safe, seedable Engines
- Mt19937 (Mersenne Twister, from mt_rand)
- PcgOneseq128XslRr64 (Permutated congruential generator)
- Xoshiro256StarStar (Xoshiro); fastest randomizer
Secure (same method as random_int/bytes uses; only CryptoSafe engine)
Implement your own (for mocks, plz no rolling your own crypto)

Constants in traits!

Cannot be referenced directly
Cannot collide with already-declared constants in class
- Can be redeclared in the class using the trait, but must be compatible
  - Same visibility
  - Same value
  - Same finality (final consts are new in PHP 8.1)
- Can import multiple traits with the same constants
  as long as they're compatible

Sansitive Parameter Value Redaction

function login(
    string $user,
    #[\SensitiveParameter] string $password
) {
    // …
    throw new Exception('Error');
}
 
login('root', 'root');

Fatal error: Uncaught Exception: Error in login.php:8
Stack trace:
#0 login.php(11): login('root', Object(SensitiveParameterValue))
#1 {main}
  thrown in login.php on line 8

Enum properties in constant expressions

enum A: string 
{
    case B = 'B';
    
    const C = [self::B->value => self::B];
}

Useful primarily for array keys mapping to enum names/values

minor tweaks

BC Breaks and Deprecations

Dynamic properties

Deprecation -> fatal in PHP 9.0
Can still use __set/__get
Can still use \stdClass
Can opt out of warning via #[AllowDynamicProperties] attribute
- Attribute is automatically inherited