title: Cocoapods: Class XX is implemented in both
body: <p>I have bunch of such errors using Firebase in my target:</p>
  
  <blockquote>
    <p>objc[13653]: Class FIRAAppEnvironmentUtil is implemented in both
    /Users/.../DataController.framework/DataController (0x10b2fe1f8) and
    /Users/.../MyApp.app/MyApp (0x1088b5d48). One of the two will be used.
    Which one is undefined.</p>
  </blockquote>
  
  <p>I have my application and several targets (some logic was moved to separate targets to maintain application more easily).</p>
  
  <p>App structure:</p>
  
  <ul>
  <li>MyApp &lt;- application</li>
  <li>DataController &lt;- app's target </li>
  <li>&lt;...> &lt;- another targets</li>
  </ul>
  
  <p>I'm using Pods, example Podfile I'm using:</p>
  
  <pre><code>platform :ios, '9.0'
  use_frameworks!
  
  target 'MyApp' do
      pod 'Test'
  end
  
  target 'DataController' do
      pod 'Firebase', '~&gt; 3.7.1'
  end
  </code></pre>
  
  <p>In my investigations I've found that <em>Pods-MyApp.debug.xcconfig</em> contains paths to ALL frameworks inside <code>FRAMEWORK_SEARCH_PATHS</code> (not only to owns frameworks, but also paths to frameworks for all targets). I don't know if it is correct, maybe that information can help.</p>
  
  <p><strong>I've tried:</strong></p>
  
  <ul>
  <li>Remove <code>Pods</code> directory</li>
  <li>Remove <code>.xcworkspace</code> file</li>
  <li>Install latest CocoaPods (1.2.0.beta.1)</li>
  </ul>
  
  <p>Nothing helped, what else I can try? That problem is only with Firebase as I see in logs, I have other Objective-C pods, but there is no such problem with them. I'm absolutely sure that Firebase module is not duplicated in main application target.</p>