title: flash notice is lost on redirect, how to find out what's removing it?
body: <p>There are many posts on SO about this ( <a href="https://stackoverflow.com/questions/6101631/respond-with-redirect-with-notice-flash-message-not-working">respond_with redirect with notice flash message not working</a>  <a href="https://stackoverflow.com/questions/4799395/why-is-notice-not-showing-after-redirect-in-rails-3">Why is :notice not showing after redirect in Rails 3</a>, among others) , I've read at least 4 and still can't solve this issue. </p>
  
  <p>I've got a portion of my site that lets people do some things before they create an account. I prefer this from a UX perspective. So they're allowed to do X and Y then they get redirected to the "Create account" page (uses Devise). </p>
  
  <p>The redirect looks like: </p>
  
  <pre><code>if userIsNew 
    ... stow information in a cookie to be retrieved later ...     
    redirect_to "/flash", flash[:notice]  
      =&gt; "Ok, we'll get right on that after you sign up (we need your email)." 
        and return # this has to be here, since I'm terminating the action early
  end 
  </code></pre>
  
  <p>So <code>"/flash"</code> is a plain page that I made to test this. It doesn't do anything, has no markup of its own, just has the basic html from the application.html, which has this line in the body: </p>
  
  <pre><code> &lt;% if flash[:notice] %&gt;
      &lt;p&gt;&lt;%= notice %&gt;&lt;/p&gt;
   &lt;% else %&gt;
    No notice!
   &lt;% end %&gt;
  </code></pre>
  
  <p>It says 'No notice' every time. </p>
  
  <p>I have tried: </p>
  
  <ul>
  <li>adding in a flash.keep to my <code>before_filter</code> in the static controller </li>
  <li>using <code>:notice =&gt;</code> instead of <code>flash[:notice] =&gt;</code></li>
  <li>putting the notice in a cookie and pulling that text out of the cookie and into a flash in the before_filter of my application controller</li>
  <li><code>redirect_to :back</code> with the <code>flash[:notice] =&gt;</code></li>
  </ul>