title: Fields not persisting using MappedSuperclass in Symfony 2/Doctrine 2?
body: <p>A <code>MappedSuperclass</code>:</p>
  
  <pre class="lang-php prettyprint-override"><code>/** @ORM\MappedSuperclass */
  abstract class AbstractMessage
  {
      /** @ORM\Column(type="text", nullable=true) */
      protected $content;
  }
  </code></pre>
  
  <p>And a child subclass, redefining <code>$content</code> to add some custom validation asserts:</p>
  
  <pre class="lang-php prettyprint-override"><code>/** @ORM\Entity */
  class InternalMessage extends AbstractMessage
  {
      /**
       * @ORM\Id
       * @ORM\Column(type="integer")
       * @ORM\GeneratedValue(strategy="AUTO")
       */
      protected $id;
  
      /**
       * @Assert\NotBlank(message="Internal message title is required.")
       */
      protected $content;
  
      /** @return integer */
      public function getId() { return $this-&gt;id; }
  
      /**
       * @param string $content
       * @return InternalMessage
       */
      public function setContent($content)
      {
          $this-&gt;content = $content;
          return $this;
      }
  
      /** @return string */
      public function getContent() { return $this-&gt;content; }
  }
  </code></pre>
  
  <h1>When <code>$content</code> override parent</h1>
  
  <p>As in my example, <code>$content</code> is not persisted! <code>null</code> field...</p>
  
  <h1>Removing <code>$content</code> from the child</h1>
  
  <p>If i remove <code>$content</code> from <code>InternalMessage</code> field is persisted, while validation does not work anymore.</p>
  
  <p>Is this a bug or something? I opened an <a href="https://github.com/symfony/symfony/issues/5156" rel="nofollow">issue</a> but don't know if it's the right place (i'm new to how github works).</p>
  
  <p>Too bad i realized that Doctrine inheritance is buggy (starting from the generator itself...).</p>