trait FooTrait {
    public function doFoo(int $value): void {
        if ($value > self::MAX_VALUE) {
            throw new \Exception('out of range');
        }
    }
}
 
class FooClass {
    private const MAX_VALUE = 42;
    use FooTrait;
}

class User {
    const HASH = 'bcrypt';
    
    public function __construct(
        public $firstName,
        public $lastName,
    ) {}
    
    public function intro()
    {
        return "My name is {$this->firstName} {$this->lastName}";
    }
}

$dan = new User('Dan', 'Murrphy');

// Dynamic propertey
$prop = 'firstName';
echo $dan->$prop;

// Dynamic variable
$var = 'dan';
echo $$var->firstName;
echo $$var->$prop;

// Dynamic method
$method = 'intro';
echo $dan->{$method}();
echo $$var->{$method}();

$dan = new User('Dan', 'Murrphy');

$constant = 'HASH';
$class = 'User';

echo User::HASH;
echo $class::HASH;

// PHP < 8.3
echo \constant("User::{$constant}");

// PHP 8.3+
echo User::{$constant};
echo $class::{$constant};

enum Hash: string {
    case Bcrypt = 'bcrypt';
    case Sha256 = 'sha256';
}

$case = 'Sha256';
$enum = 'Hash';

echo Hash::Sha256->value;
echo $enum::Sha256->value;

// PHP < 8.3
echo \constant("Hash::{$case}")->value;

// PHP 8.3+
echo Hash::{$case};
echo $enum::{$case};

unserialize('foo');
// Notice: unserialize(): Error at offset 0 of 3 bytes

unserialize('i:12345678901234567890;'); 
// Warning: unserialize(): Numerical result out of range

unserialize('E:3:"foo";'); 
// Warning: unserialize(): Invalid enum name 'foo' (missing colon)
// Notice: unserialize(): Error at offset 0 of 10 bytes

unserialize('E:3:"fo:";'); 
// Warning: unserialize(): Class 'fo' not found
// Notice: unserialize(): Error at offset 0 of 10 bytes

try {
    unserialize('O:19:"SplDoublyLinkedList":3:{i:0;i:0;i:1;N;i:2;a:0:{}}');
} catch (UnexpectedValueException $e) {
    echo $e->getMessage(); 
    // Incomplete or ill-typed serialization data
}
 
try {
    unserialize(
        'a:2:{i:12345678901234567890;O:19:"SplDoublyLinkedList":3:{i:0;i:0;i:1;N;i:2;a:0:{}}}'
    ); 
    // Warning: unserialize(): Numerical result out of range
    // Notice: unserialize(): Unexpected end of serialized data
    // Notice: unserialize(): Error at offset 83 of 84 bytes
} catch (UnexpectedValueException $e) {
    echo $e->getMessage(); 
    // Incomplete or ill-typed serialization data
}
 

try {
    set_error_handler(static function ($severity, $message, $file, $line) {
        throw new \ErrorException($message, 0, $severity, $file, $line);
    });
    
    $result = unserialize($serialized);
} catch (\Throwable $e) {
    // Unserialization failed.
    // Catch block optional if the error should not be handled.
} finally {
    restore_error_handler();
}
 
// Do something with the $result. Must not appear
// in the 'try' to not 'catch' unrelated errors.
var_dump($result);

try {
    $result = unserialize($serialized);
    
    // Do something with the $result
    // Can appear in the 'try'
    var_dump($result); 
} catch (\UnserializationFailureException $e) {
    // unserialization failed.
    var_dump($e->getPrevious());
}