module GraphQL::StaticValidation::MutationRootExists

def on_operation_definition(node, _parent)
  if node.operation_type == 'mutation' && context.warden.root_type_for_operation("mutation").nil?
    add_error(GraphQL::StaticValidation::MutationRootExistsError.new(
      'Schema is not configured for mutations',
      nodes: node
    ))
  else
    super
  end
end