symfony/routing · error · InvalidArgumentException

Invalid resource " " passed to the route loader: use the…

Error message

Invalid resource "%s" passed to the %s route loader: use the format "object_id::method" or "object_id" if your object class has an "__invoke" method.

What it means

ObjectLoader::load() expects a routing resource string identifying an object method in the form 'object_id::method', or just 'object_id' when the service class has an __invoke method. Any resource string not matching this pattern is rejected with InvalidArgumentException before the loader even resolves the object.

Solutions

1. Use a service id followed by :: and the method name, e.g. 'app.route_loader::loadRoutes'
2. If using __invoke, pass only the service id, e.g. 'app.route_loader'
3. Check the resource string for typos — stray '::', file paths, or FQCNs with backslashes are not accepted; register the class as a service and use its id

Example fix

# before (config/packages/routing.yaml)
app_routes:
    resource: 'App\Routing\RoutesLoader::load'
    type: service

# after
app_routes:
    resource: 'app.routing.routes_loader::load'
    type: service

if (!preg_match('/^[^:]+(?:::(?:[^:]+))?$/', $resource)) {
    throw new \InvalidArgumentException('Resource must be "object_id::method" or "object_id".');
}

function isValidObjectResource(string $resource): bool { return preg_match('/^[^:]+(?:::(?:[^:]+))?$/', $resource) === 1; }

try { $collection = $loader->load($resource, 'service'); } catch (\InvalidArgumentException $e) { /* fix resource format to object_id::method */ }

When it happens

Trigger: Passing a malformed resource to the object route loader, e.g. containing extra colons ('service::method::extra'), absolute file paths, class::staticMethod (static call syntax is fine per regex but plain strings with slashes/URLs are not), or an empty string.

Common situations: Configuring type: service imports with a wrong resource syntax; pasting a file path or controller action string ('App\\Controller::index' with a namespace — namespaces contain backslashes which fail the regex) instead of a service id.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• Method " " not found on " " when importing routing resource…
• Parameter " " for route " " must match " " (" " given) to…
• Parameters for route
• Route aliases cannot be used on non-invokable class
• The " ()" method must not be called.

AI-assisted analysis of symfony/routing@83fa223250 (2026-09-14). Data as JSON: /api/errors/97a7dde47cc34a3d. Report an issue: GitHub.

Appendix: source

Thrown at Loader/ObjectLoader.php:39

 * @author Ryan Weaver <ryan@knpuniversity.com>
 */
abstract class ObjectLoader extends Loader
{
    /**
     * Returns the object that the method will be called on to load routes.
     *
     * For example, if your application uses a service container,
     * the $id may be a service id.
     */
    abstract protected function getObject(string $id): object;

    /**
     * Calls the object method that will load the routes.
     */
    public function load(mixed $resource, ?string $type = null): RouteCollection
    {
        if (!preg_match('/^[^\:]+(?:::(?:[^\:]+))?$/', $resource)) {
            throw new \InvalidArgumentException(\sprintf('Invalid resource "%s" passed to the %s route loader: use the format "object_id::method" or "object_id" if your object class has an "__invoke" method.', $resource, \is_string($type) ? '"'.$type.'"' : 'object'));
        }

        $parts = explode('::', $resource);
        $method = $parts[1] ?? '__invoke';

        $loaderObject = $this->getObject($parts[0]);

        if (!\is_callable([$loaderObject, $method])) {
            throw new \BadMethodCallException(\sprintf('Method "%s" not found on "%s" when importing routing resource "%s".', $method, get_debug_type($loaderObject), $resource));
        }

        $routeCollection = $loaderObject->$method($this, $this->env);

        if (!$routeCollection instanceof RouteCollection) {
            $type = get_debug_type($routeCollection);

            throw new \LogicException(\sprintf('The "%s::%s()" method must return a RouteCollection: "%s" returned.', get_debug_type($loaderObject), $method, $type));
        }

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