AbstractController::DoubleRenderError

[soulim]

Hi,

I have AbstractController::DoubleRenderError in UsersController#create when I'm trying to create user account via OpenID.

The code of create action:

def create
  @user = User.new(params[:user])
  @user.save do |result|
    if result
      flash[:notice] = "Account registered!"
      redirect_to root_url
    else
      redirect_to sign_up_url
    end
  end
end

Parameters for create action:

{"commit"=>"Register",
"authentication_type"=>"user",
"authenticity_token"=>"+X7c+p3LvOQ0Bt38wvu3kykY2UAkKyqaII0yiCPQ7ks=",
"utf8"=>"\342\234\223",
"openid_identifier"=>"username.myopenid.com"}

I'm using Rails 3 and REE.