Helper methods not called synchronously

output.txt

Started GET "/plugins/1" for 127.0.0.1 at 2012-07-27 08:12:13 -0400
  Processing by PluginsController#show as HTML
  Parameters: {"id"=>"1"}
  Plugin Load (0.1ms)  SELECT `plugins`.* FROM `plugins` WHERE `plugins`.`id` = 1 LIMIT 1
Rendered plugins/show.html.erb (0.3ms)
Completed 200 OK in 110ms (Views: 2.2ms | ActiveRecord: 0.1ms)
Private User
Rendering Plugin


Started GET "/plugins/3" for 127.0.0.1 at 2012-07-27 08:12:13 -0400
  Processing by PluginsController#show as HTML
  Parameters: {"id"=>"3"}
  Plugin Load (0.1ms)  SELECT `plugins`.* FROM `plugins` WHERE `plugins`.`id` = 3 LIMIT 1
Redirecting to login
Redirected to http://localhost:3000/login
  CACHE (0.0ms)  SELECT `plugins`.* FROM `plugins` WHERE `plugins`.`id` = 3 LIMIT 1
Completed 500 Internal Server Error in 116ms

AbstractController::DoubleRenderError (Render and/or redirect were called multiple times in this action. Please note that you may only call render OR redirect, and at most once per action. Also note that neither redirect nor render terminate execution of the action, so if you want to exit an action after redirecting, you need to do something like "redirect_to(...) and return".):
  app/controllers/plugins_controller.rb:75:in `show'

Rendered .rvm/gems/ruby-1.9.2-p290@rails3013/gems/actionpack-3.0.13/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.4ms)
Rendered .rvm/gems/ruby-1.9.2-p290@rails3013/gems/actionpack-3.0.13/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (2.9ms)
Rendered .rvm/gems/ruby-1.9.2-p290@rails3013/gems/actionpack-3.0.13/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (9.1ms)

plugins_controllers.rb

class ApplicationController < ActionController::Base
  helper :all
  def require_user
    unless current_user
      puts "Redirecting to login"
      redirect_to :login_path and return 
    end
  end
end

class PluginsController < ApplicationController
  def show
    plugin = Plugin.find(params[:id])
    if plugin.private?
      puts "Private User"
      require_user
    end
    puts "Rendering plugin"
    render :text => "Display Plugin", :layout => true
  end
end