PHP8.3版本正式发布——更好的性能、语法及类型安全

 PHP 8.3 是 PHP 语言的主版本更新。它包含了许多新功能，它包含了许多新功能，例如：类常量显式类型、只读属性深拷贝，以及对随机性功能的补充。一如既往，它还包括性能改进、错误修复和常规清理等。

类型化类常量
PHP < 8.3 interface I { // We may naively assume that the PHP constant is always a string. const PHP = 'PHP 8.2'; } class Foo implements I { // But implementing classes may define it as an array. const PHP = []; } PHP 8.3 interface I { const string PHP = 'PHP 8.3'; } class Foo implements I { const string PHP = []; } // Fatal error: Cannot use array as value for class constant // Foo::PHP of type string 动态获取类常量 PHP < 8.3 class Foo { const PHP = 'PHP 8.2'; } $searchableConstant = 'PHP'; var_dump(constant(Foo::class . "::{$searchableConstant}")); PHP 8.3 class Foo { const PHP = 'PHP 8.3'; } $searchableConstant = 'PHP'; var_dump(Foo::{$searchableConstant}); 新增 #[\Override] 属性 PHP < 8.3 use PHPUnit\Framework\TestCase; final class MyTest extends TestCase { protected $logFile; protected function setUp(): void { $this->logFile = fopen('/tmp/logfile', 'w'); } protected function taerDown(): void { fclose($this->logFile); unlink('/tmp/logfile'); } } // The log file will never be removed, because the // method name was mistyped (taerDown vs tearDown). 
PHP 8.3 use PHPUnit\Framework\TestCase; final class MyTest extends TestCase { protected $logFile; protected function setUp(): void { $this->logFile = fopen('/tmp/logfile', 'w'); } #[\Override] protected function taerDown(): void { fclose($this->logFile); unlink('/tmp/logfile'); } } // Fatal error: MyTest::taerDown() has #[\Override] attribute, // but no matching parent method exists 
通过给方法添加 #[\Override] 属性，PHP 将确保在父类或实现的接口中存在同名的方法。添加该属性表示明确说明覆盖父方法是有意为之，并且简化了重构过程，因为删除被覆盖的父方法将被检测出来。

只读属性深拷贝
PHP < 8.3 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 $instance; // Fatal error: Cannot modify readonly property Foo::$php 
PHP 8.3 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; $cloned->php->version = '8.3'; 
readonly 属性现在可以在魔术方法 __clone 中被修改一次，以此实现只读属性的深拷贝

新增 json_validate() 函数
PHP < 8.3 function json_validate(string $string): bool { json_decode($string); return json_last_error() === JSON_ERROR_NONE; } var_dump(json_validate('{ "test": { "foo": "bar" } }')); // true PHP 8.3 var_dump(json_validate('{ "test": { "foo": "bar" } }')); // true json_validate() 可以检查一个字符串是否为语法正确的 JSON，比 json_decode() 更有效。 新增 Randomizer::getBytesFromString() 方法 PHP < 8.3 // This function needs to be manually implemented. function getBytesFromString(string $string, int $length) { $stringLength = strlen($string); $result = ''; for ($i = 0; $i < $length; $i++) { // random_int is not seedable for testing, but secure. $result .= $string[random_int(0, $stringLength - 1)]; } return $result; } $randomDomain = sprintf( "%s.example.com", getBytesFromString( 'abcdefghijklmnopqrstuvwxyz0123456789', 16, ), ); echo $randomDomain; PHP 8.3 // A \Random\Engine may be passed for seeding, // the default is the secure engine. $randomizer = new \Random\Randomizer(); $randomDomain = sprintf( "%s.example.com", $randomizer->getBytesFromString( 'abcdefghijklmnopqrstuvwxyz0123456789', 16, ), ); echo $randomDomain; 
在 PHP 8.2 中新增的 Random 扩展 通过一个新方法生成由特定字节组成的随机字符串。这种方法可以使开发者更轻松的生成随机的标识符（如域名），以及任意长度的数字字符串。

新增 Randomizer::getFloat() 和 Randomizer::nextFloat() 方法
PHP < 8.3 // Returns a random float between $min and $max, both including. function getFloat(float $min, float $max) { // This algorithm is biased for specific inputs and may // return values outside the given range. This is impossible // to work around in userland. $offset = random_int(0, PHP_INT_MAX) / PHP_INT_MAX; return $offset * ($max - $min) + $min; } $temperature = getFloat(-89.2, 56.7); $chanceForTrue =