title: Entity field array type in forms
body: <p>I have an entity</p>
  
  <pre><code>class Icon
  {
  ...
  
       /**
       * @var array $padding
       *
       * @ORM\Column(name="padding", type="array")
       */
      private $padding;
  
      /**
       * Set padding
       *
       * @param array $padding
       * @return Icon
       */
      public function setPadding($padding)
      {
          $this-&gt;padding = $padding;
          return $this;
      }
  
      /**
       * Get padding
       *
       * @return array
       */
      public function getPadding()
      {
          return $this-&gt;padding;
      }
  
  ...
  }
  </code></pre>
  
  <p>, an icon form</p>
  
  <pre><code>&lt;?php
  
  namespace Acme\ExBundle\Form;
  
  use Symfony\Component\Form\AbstractType;
  use Symfony\Component\Form\FormBuilderInterface;
  use Symfony\Component\OptionsResolver\OptionsResolverInterface;
  
  class IconPaddingType extends AbstractType
  {
      public function buildForm(FormBuilderInterface $builder, array $options)
      {
          $builder
              -&gt;add('padding', new PaddingType())
          ;
      }
  
      public function setDefaultOptions(OptionsResolverInterface $resolver)
      {
          $resolver-&gt;setDefaults(array(
              'data_class' =&gt; 'Acme\ExBundle\Entity\Icon'
          ));
      }
  
      public function getName()
      {
          return 'icontype';
      }
  }
  </code></pre>
  
  <p>and a padding form</p>
  
  <pre><code>&lt;?php
  
  namespace Acme\ExBundle\Form;
  
  use Symfony\Component\Form\AbstractType;
  use Symfony\Component\Form\FormBuilderInterface;
  use Symfony\Component\OptionsResolver\OptionsResolverInterface;
  
  class PaddingType extends AbstractType
  {
      public function buildForm(FormBuilderInterface $builder, array $options)
      {
          $builder
              -&gt;add('top', 'integer', array('data' =&gt; 0))
              -&gt;add('right', 'integer', array('data' =&gt; 0))
              -&gt;add('bottom', 'integer', array('data' =&gt; 0))
              -&gt;add('left', 'integer', array('data' =&gt; 0))
          ;
      }
  
      public function setDefaultOptions(OptionsResolverInterface $resolver)
      {
      }
  
      public function getName()
      {
          return 'paddingtype';
      }
  }
  </code></pre>
  
  <p>If I create or update icon with <code>IconType</code></p>
  
  <p>and fill paddings, icon saves as I expect.</p>
  
  <p>But after this when I edit icon again,</p>
  
  <p><code>PaddingForm</code> does not use <code>icon.padding</code> values</p>
  
  <p>to populate the form ( top, left, right, bottom are '0' again).</p>
  
  <p>How do you fill embed <code>PaddingForm</code> with <code>icon.padding</code> values?</p>