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PORailstutorial: Putting flash messages in partial yields error "undefined method `each' for nil:NilClass"?
 

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  1. PORailstutorial: Putting flash messages in partial yields error "undefined method `each' for nil:NilClass"?
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    <blockquote> <p><strong>Possible Duplicate:</strong><br> <a href="https://stackoverflow.com/questions/3111844/flash-messages-in-partials-rails-3">Flash Messages in Partials (Rails 3)</a> </p> </blockquote> <p>I am doing Michael Hartl's Railstutorial and <a href="http://ruby.railstutorial.org/chapters/sign-up#code-layout_flash" rel="nofollow noreferrer">listing 7.26</a> adds flash messages to the application layout:</p> <pre><code>&lt;!DOCTYPE html&gt; &lt;html&gt; . . . &lt;body&gt; &lt;%= render 'layouts/header' %&gt; &lt;div class="container"&gt; &lt;% flash.each do |key, value| %&gt; &lt;div class="alert alert-&lt;%= key %&gt;"&gt;&lt;%= value %&gt;&lt;/div&gt; &lt;% end %&gt; &lt;%= yield %&gt; &lt;%= render 'layouts/footer' %&gt; &lt;%= debug(params) if Rails.env.development? %&gt; &lt;/div&gt; . . . &lt;/body&gt; &lt;/html&gt; </code></pre> <p>This works fine.</p> <p>However, I tried to clean up this code by creating a _flash.html.erb in my partial folder...</p> <pre><code>&lt;% flash.each do |key,value| %&gt; &lt;%= content_tag(:div, value, class: "alert alert-#{key}") %&gt; &lt;!-- &lt;div class="alert alert-&lt;%= key %&gt;"&gt;&lt;%= value %&gt;&lt;/div&gt; --&gt; &lt;% end %&gt; </code></pre> <p>...and than using...</p> <pre><code>&lt;%= render 'partials/flash' %&gt; </code></pre> <p>...in my application layout all my Rspec tests start failing with the following message for each test:</p> <pre><code> Failure/Error: before { visit signup_path } ActionView::Template::Error: undefined method `each' for nil:NilClass </code></pre> <p>The key issue seems to be that flash is nil because wrapping my _flash partial in an if statement like this...</p> <pre><code>&lt;% unless flash.empty? %&gt; &lt;% flash.each do |key,value| %&gt; &lt;%= content_tag(:div, value, class: "alert alert-#{key}") %&gt; &lt;!-- &lt;div class="alert alert-&lt;%= key %&gt;"&gt;&lt;%= value %&gt;&lt;/div&gt; --&gt; &lt;% end %&gt; &lt;% end %&gt; </code></pre> <p>... yields the same error message about NilClass as above and wrapping it in an if statement like this...</p> <pre><code>&lt;% if flash %&gt; &lt;% flash.each do |key,value| %&gt; &lt;%= content_tag(:div, value, class: "alert alert-#{key}") %&gt; &lt;!-- &lt;div class="alert alert-&lt;%= key %&gt;"&gt;&lt;%= value %&gt;&lt;/div&gt; --&gt; &lt;% end %&gt; &lt;% end %&gt; </code></pre> <p>... breaks the flash messages from working (because 'if flash' is always false).</p> <p>I have two related questions:</p> <ol> <li><p>Why/how exactly does using the partials/flash solution change the behavior of a rails app?</p></li> <li><p>How to change my partials/flash so it will work?</p></li> </ol> <p>Thanks! </p>
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