<h2 id="heading-background">Background</h2>
<p>Today I encountered with the following error.  I didn't know what might be the cause of this error.</p>
<h3 id="heading-expected-culprit">Expected Culprit</h3>
<pre><code class="lang-ruby">SystemStackError <span class="hljs-keyword">in</span> DashboardsController<span class="hljs-comment">#show</span>
stack level too deep

Extracted source (around line <span class="hljs-comment">#11):</span>

    <span class="hljs-keyword">else</span>
      &gt; @questions = current_organization.questions.in_dashboard
        @subjects  = current_organization.subjects.in_dashboard
    <span class="hljs-keyword">end</span>
  <span class="hljs-keyword">end</span>

Rails.<span class="hljs-symbol">root:</span> /Users/john/projects/lgprofile

Application Trace <span class="hljs-params">| Framework Trace |</span> Full Trace
app/controllers/dashboards_controller.<span class="hljs-symbol">rb:</span><span class="hljs-number">11</span><span class="hljs-symbol">:in</span> <span class="hljs-string">`show'</span>
</code></pre>
<p>The code in line no#11 looks fine to me. It was n't changed in a few days. This should not be the cause.
I then checked the associations. May be something changed and is causing this error. I found no
 changes in the model association code.</p>
<p>While going through the <code>git diff</code> I saw some new line in model like</p>
<h3 id="heading-real-culprit">Real Culprit</h3>
<pre><code class="lang-ruby">  +  scope <span class="hljs-symbol">:parents</span>, -&gt; { where(<span class="hljs-symbol">question_id:</span> <span class="hljs-literal">nil</span>) }
  +
</code></pre>
<p>When I commented this code, the app started running again.</p>
<h2 id="heading-reason-behind-this-error">Reason behind this error</h2>



## Background

Today I encountered with the following error.  I didn't know what might be the cause of this error.

### Expected Culprit
```ruby
SystemStackError in DashboardsController#show
stack level too deep

Extracted source (around line #11):

    else
      > @questions = current_organization.questions.in_dashboard
        @subjects  = current_organization.subjects.in_dashboard
    end
  end

Rails.root: /Users/john/projects/lgprofile

Application Trace | Framework Trace | Full Trace
app/controllers/dashboards_controller.rb:11:in `show'

```


The code in line no#11 looks fine to me. It was n't changed in a few days. This should not be the cause.
I then checked the associations. May be something changed and is causing this error. I found no
 changes in the model association code.

While going through the `git diff` I saw some new line in model like

### Real Culprit

```ruby
  +  scope :parents, -> { where(question_id: nil) }
  +
```

When I commented this code, the app started running again.

## Reason behind this error


Shiva's Blog

Shiva's Blog

SystemStackError: stack level too deep

Background

Expected Culprit

Real Culprit

Reason behind this error