Keep instance

SFactory.php

interface F{}

class Article implements F
{
public function __construct(public readonly string $foo)
{
}
}

interface FactoryAwareInterface{
    public static function getInstance(string $className, ...$with): F;
}

trait ClassInstanceCached
{
    private static object $real;

    public static function getInstance(string $className, ...$with): F
    {
        return self::$real ??= (new static())->build($className, ...$with);
    }
}
class FactoryAware implements FactoryAwareInterface
{
    use ClassInstanceCached;
    public static function build(string $className, ...$with): F
    {
        if(is_a($className, F::class, true)) {
            return new $className(...$with);
        }
        
        throw new RuntimeError("Not a F");
    }
}

$a = FactoryAware::getInstance(Article::class, "foo");
$sameAsA = FactoryAware::getInstance(Article::class, "foo");
$sameAsABis = FactoryAware::getInstance(Article::class, "foo");