symfony/http-kernel · error · InvalidArgumentException

Controller " " cannot be fetched from the container because…

Error message

Controller "%s" cannot be fetched from the container because it is private. Did you forget to tag the service with "controller.service_arguments"?

What it means

Symfony's ContainerControllerResolver found a controller id in the compiled container's list of removed (private, unused) service ids. The service was removed at compile time because nothing makes it public/autowired as a controller, so it cannot be fetched at runtime and an InvalidArgumentException is thrown.

Solutions

1. Tag the service with controller.service_arguments in services.yaml so it is made public/autowired for controllers
2. Prefer relying on Symfony's default autoconfiguration: put the class under the controllers namespace or add _instanceof + autoconfigure: true
3. If not a real controller, fix the route's _controller value to point at the correct class/service id
4. Pass constructor arguments explicitly in the route defaults if the controller cannot be a service

Example fix

# before (services.yaml)
App\Controller\FooController:
    public: false

// after
services:
    App\Controller\FooController:
        tags: ['controller.service_arguments']

if ($this->container instanceof Container && isset($this->container->getRemovedIds()[$controllerId])) {
    // controller service is private/removed: fix registration before dispatch
}

function isPublicControllerService(ContainerInterface $c, string $id): bool {
    return !$c instanceof Container || !isset($c->getRemovedIds()[$id]);
}

try { $controller = $resolver->getController($request); } catch (\InvalidArgumentException $e) {
    // check for 'cannot be fetched from the container because it is private'
}

When it happens

Trigger: Requesting a route whose _controller is a service id (e.g. 'App\Controller\FooController') but the service is private and not tagged with controller.service_arguments (or not auto-registered via the _instanceof controller.service_attributes defaults). Also occurs when services.yaml sets 'public: false' with 'autoconfigure: false' or the class lives outside the controllers autoloaded namespace.

Common situations: Controller defined manually in services.yaml without the controller.service_arguments tag; services.yaml using 'resource: .' with excluded controller dirs; class outside App\ namespace not matched by the framework.controller autoconfig; Symfony upgrades where autconfigure behavior changed.

Understand the failure class

Background: "not installed", "pip install", "required for": how missing-dependency errors surface across open-source libraries — this error's family across 34 libraries.

Related errors

• Controller " " has required constructor arguments and does…
• Controller " " does neither exist as service nor as class.
• The controller for URI
• Message built by getControllerError(): e.g. Function
• Users will expect the alias of the default extension of a…

AI-assisted analysis of symfony/http-kernel@aa3a39d728 (2026-09-13). Data as JSON: /api/errors/abab0d9fa56abaef. Report an issue: GitHub.

Appendix: source

Thrown at Controller/ContainerControllerResolver.php:58

        try {
            return parent::instantiateController($class);
        } catch (\Error $e) {
        }

        $this->throwExceptionIfControllerWasRemoved($class, $e);

        if ($e instanceof \ArgumentCountError) {
            throw new \InvalidArgumentException(\sprintf('Controller "%s" has required constructor arguments and does not exist in the container. Did you forget to define the controller as a service?', $class), 0, $e);
        }

        throw new \InvalidArgumentException(\sprintf('Controller "%s" does neither exist as service nor as class.', $class), 0, $e);
    }

    private function throwExceptionIfControllerWasRemoved(string $controller, \Throwable $previous): void
    {
        if ($this->container instanceof Container && isset($this->container->getRemovedIds()[$controller])) {
            throw new \InvalidArgumentException(\sprintf('Controller "%s" cannot be fetched from the container because it is private. Did you forget to tag the service with "controller.service_arguments"?', $controller), 0, $previous);
        }
    }
}

View on GitHub (pinned to aa3a39d728)