Why is this double render error appearing?

Question

In my rails app all of a sudden i keep getting a double render error (Render and/or redirect were called multiple times in this action. Please note that you may only call render OR redirect, and at mos ....etc...) and i could not for the life of me figure out where the double render is. It comes when the user types in a query that is not the proper format. Here is the code that checks the format and displays errors:

 def if_user_formulated_request_properly
    unless request.post?
      flash[:error] = "This page can only be accessed through the search page. (POST request only)"
      redirect_to(:action => "index") and return
    end
    if params[:query].blank?
      flash[:error] = "Search criteria can not be blank"
      redirect_to(:action => "index") and return
    end
    if !(params[:query] =~ /-/)
      flash[:error] = %( Format of search criteria is wrong.<br /> Should be [IXLSpecClass value][year]-[Message ID] for example GP07-8)
      redirect_to(:action => "index") and return
    end

    if !(QueryParser.expression.match(params[:query]))
      flash[:error] = %( Format of search criteria is wrong.<br /> Should be [IXLSpecClass value][year]-[Message ID] for example GP07-8)
      redirect_to(:action => "index") and return
    end

Any suggestions?

UPDATE

Controller action code as requested:

def show
  if_user_formulated_request_properly do
    @input_messages = InputMessage.search_by(params[:query].strip) unless params[:query].blank?
  end
  respond_to do |format|
    format.html #default rendering
  end
end

Answer 1

I'll suggest a refactoring for the action code and leave it to you to refactor the rest . . .

def show
  unless user_formulated_request_properly?
    redirect_to(:action => "index")
    return
  end
  respond_to do |format|
    format.html 
  end
end

In case it's not obvious, you shouldn't have any redirect calls in user_formulated_request_properly?, and you shouldn't be calling yield either. (imho, yield is the most overused ruby language feature)

Answer 2

I'm making some assumptions about your code.

Assuming that if_user_formulated_request_properly is not the action of your controller, your controller action is calling this method. When you do a return, you exit if_user_formulated_request_properly, but control goes back to the code in your action method.

I think you are expecting it to return from the action method, but that's not what happens. Instead, it goes to the next line in the action.