title: respond_with is redirecting to specified location even on validation errors, in rails3
body: <p>When using location in respond with, it is ignoring validation errors and redirecting to the specified location. Is this expected behavior?</p>
  
  <p>I checked in the <a href="https://github.com/rails/rails/blob/600a89f2082beadf4af9fe140a1a2ae56386cd49/actionpack/lib/action_controller/metal/responder.rb" rel="nofollow">responder module</a> that it checking if there are any errors on the model. I inspected the model and it contains validation errors in the @solution object. What am I missing here?</p>
  
  <p>controller:</p>
  
  <pre><code>def create
    @problem = Problem.find(params[:problem_id])
    @solution = @problem.solutions.build params[:solution]
    @solution.save
    respond_with(@solution, :location =&gt; detail_problem_solution_path(@problem, @solution)
  end
  </code></pre>
  
  <p>model:</p>
  
  <pre><code>  validates :body, :presence =&gt; true, :unless =&gt; :reference
  </code></pre>
  
  <p>reference is true or false false.</p>