<?php
declare(strict_types=1);

require __DIR__ . '/vendor/autoload.php';

class CidHolder {
    public function __construct(public readonly int|string $cid)
    {
    }
}

class SomeDependency {}

class MyService {
    private string|int $cid;

    public function __construct(
        CidHolder $cidHolder,
        private readonly SomeDependency $dependency
    ) {
        $this->cid = $cidHolder->cid;
    }
}

$containerBuilder = new \DI\ContainerBuilder();
$containerBuilder->useAutowiring(true);
$containerBuilder->addDefinitions([
    CidHolder::class => \DI\factory(function () {
       return new CidHolder($_SESSION['client']['cid'] ?? 'unknown');
    }),
]);

$container = $containerBuilder->build();

var_dump($container->get(MyService::class));