Youshido\GraphQL\Execution\Request::getVariableReferences PHP Метод

    public function getVariableReferences()
    {
        return $this->variableReferences;
    }

 private function assertAllVariablesExists(Request $request)
 {
     foreach ($request->getVariableReferences() as $variableReference) {
         if (!$variableReference->getVariable()) {
             throw new InvalidRequestException(sprintf('Variable "%s" not exists', $variableReference->getName()), $variableReference->getLocation());
         }
     }
 }