Weird behavior with uninitialized typed properties and __set/__get

Uninitialized typed properties 2.bug

Link: https://bugs.php.net/bug.php?id=78859

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Weird behavior with uninitialized typed properties and __set/__get


Seems calling a constructor is triggering __set magic for uninitialized typed properties. So it does not matter the property is public or private/protected.

I suppose the problem is __set/__get called before __construct when a type is given to a property. Also I if remove __get then I get object(acme\Options)#1 (1) { ["stack"]=> array(1) { ["stack"]=> array(1) { ["one"]=> int(1) } } }.


Test script:

final class Options {
    // This is OK but why redundant initialization?
    // public array $stack = [];
    public array $stack;

    public function __construct(array $stack) {
        $this->stack = $stack;
    }

    public function __set(string $name, $value) {
        // if (empty($this->stack)) {
        //     // This line below yields: object(acme\Options)#1 (0) { ["stack"]=> uninitialized(array) }.
        //     // return;
        //     // This line below yields: object(acme\Options)#1 (1) { ["stack"]=> array(1) { ["stack"]=> array(1) { ["one"]=> int(1) } } }.
        //     // $this->stack = [];
        // }

        // This is solving problem but the purpose is not that also corrupting $stack structure inserting a new sub-array.
        // object(acme\Options)#1 (1) { ["stack"]=> array(2) { ["one"]=> int(1) ["stack"]=> array(1) { ["one"]=> int(1) } } }
        // $this->stack = $value;

        // This is indicating that __set called before (before __construct).
        // throw new \Exception();

        // This is problematic part.
        $this->stack[$name] = $value;
    }

    public function __get(string $name) {
        // This is indicating that __get called before (before __construct).
        // throw new \Exception();

        return $this->stack[$name] ?? null;
    }
}

var_dump(new Options(['one' => 1]));


Expected result:

object(acme\Options)#1 (1) {
  ["stack"]=>
  array(1) {
    ["one"]=>
    int(1)
  }
}


Actual result:

PHP Notice:  Indirect modification of overloaded property acme\Options::$stack has no effect in /var/www/a.php on line 19
PHP Fatal error:  Uncaught TypeError: Typed property acme\Options::$stack must be array, null used in /var/www/a.php:19
Stack trace:
#0 /var/www/a.php(16): acme\Options->__set()
#1 /var/www/a.php(26): acme\Options->__construct()
#2 {main}
  thrown in /var/www/a.php on line 19