ruby on rails - Why flash message won't disappear?

Question

I am doing some exception handling in my controller, when there is an exception thrown in :create action, I will render to the :new action and show a flash message.

Everything works fine, I can see the flash message when exception caught, but when I redirect to(handly click) other page, the flash message still here. Then I redirect to another page(the second handly click), the message could disappear.

Anyone who knows what is the reason?

My controller code:

class MessagesController < ApplicationController
  rescue_from Exception, :with => :render_new

  def new
  end

  def create
  end

private
  def render_new
    flash[:alert] = t("uploading_error")
    render :action => :new
  end
end

My layout code (Haml):

%body
  #content
    - unless flash[:alert].blank?
      #alert= flash[:alert]

Answer 1

Replace

flash[:alert] = t("uploading_error")

with

flash.now.alert = t("uploading_error")

and see if that is the result you expect?

flash[:alert] will stay around for the next page (hence it only disappears at the second redirect); but flash.now.alert will only display for the current page.