PHP Overridden Method

class ParentClass 
{
    public function __construct(int $id) 
    {
        // Base initialization logic
    }

    /**
     * Base method to be overridden.
     */
    protected function processData(array $payload): object 
    {
        // Casting an array to an object inherently creates a stdClass instance
        return (object) $payload;
    }

    /**
     * This method cannot be overridden by any child class.
     */
    final public function getIdentifier(): string 
    {
        return static::class;
    }
}

class ChildClass extends ParentClass 
{
    /**
     * Constructor Exemption:
     * The child constructor can have a completely different signature.
     */
    public function __construct(string $uuid) 
    {
        // Explicitly invoking the parent constructor is required to run its logic
        parent::__construct((int) $uuid);
    }

    /**
     * Overridden method demonstrating PHP's overriding rules:
     * 1. Visibility widened (protected -> public).
     * 2. Parameter type widened (array -> iterable) [Contravariance].
     * 3. New optional parameter added ($log).
     * 4. Return type narrowed (object -> stdClass) [Covariance].
     */
    public function processData(iterable $payload, bool $log = false): stdClass 
    {
        // Convert iterable to array to satisfy the parent's strict signature
        $arrayPayload = is_array($payload) ? $payload : iterator_to_array($payload);

        // Explicitly invoking the shadowed parent method
        $baseObject = parent::processData($arrayPayload);

        // Child-specific mutation
        $baseObject->isProcessed = true;
        $baseObject->isLogged = $log;

        // $baseObject is already a stdClass (from the parent's array-to-object cast),
        // satisfying the covariant return type declaration.
        return $baseObject;
    }
}