Accessing session from request stack

[szymach]

Hello,

I have a private library for handling translations, which works in a way where you have a translatable entity and a collection of translation entities for it, each for a different locale. Each time the translatable entity is being created or modified via Doctrine's Unit of Work, the current locale is being checked and either a new translation is created or an existing one is modified. The locale is checked like so, through a dedicated service:

final class LocaleProvider 
{
    private const SESSION_KEY = 'key';

    private RequestStack $requestStack;
    private string $defaultLocale; // `%kernel.default_locale%`

    public function getLocale(): string
    {
        $savedLocale = $this->getSavedLocale();
        if (null !== $savedLocale) {
            return $savedLocale;
        }

        $request = $this->requestStack->getCurrentRequest();
        if (null !== $request) {
            return $request->getLocale();
        }

        return $this->defaultLocale;
    }

    private function getSavedLocale(): ?string
    {
        $session = $this->getSession();
        if (null === $session) {
            return null;
        }

        return $session->get(self::SESSION_KEY);
    }

    private function getSession(): ?SessionInterface
    {
        $currentRequest = $this->requestStack->getCurrentRequest();
        if (null === $currentRequest) {
            return null;
        }

        return $currentRequest->getSession();
    }
}

The library worked just fine until I switched from accessing the session service directly from the container to accessing the instance from the request_stack, as seen above. Basically, $this->requestStack->getCurrentRequest() (or any other of it's methods) never returns an actual request. From analyzing the code it seems that there is a RequestStack being created in the HttpKernel used by Symfony module, but from what I have checked it is not the same instance that gets injected into my LocaleProvider service. Is there anything that I am missing here?