title: Woocommerce Sessions: woocommerce_get_cart_item_from_session
body: <p>I have created a plugin mainly following <a href="http://www.xatik.com/2013/02/06/add-custom-form-woocommerce-product/2/" rel="nofollow">this guide</a>, which simply adds a small bit of data to a given product.</p>
  
  <p>I know Woocommerce have made some changes <a href="http://www.skyverge.com/blog/migrating-your-plugin-woocommerce-2-0/#order_item_data" rel="nofollow">outlined here</a>.</p>
  
  <p>The problem I'm having is that when I add my item to the cart, and access the cart page, I am getting a blank screen. I believe the problem stems from the use of this filter:</p>
  
  <blockquote>
    <p>add_filter('woocommerce_get_cart_item_from_session'...</p>
  </blockquote>
  
  <p>If I comment the line with this filter, my checkout page works (but without the extra details added to my product). I can't work out why this filter is not working, or what problem it is having??</p>
  
  <p>The woocommerce changes said:</p>
  
  <blockquote>
    <p>WooCommerce 2.0 no longer uses the PHP session_start function, instead it makes use of WordPress’ transients, which is great, unless your code happens to rely on $_SESSION. </p>
  </blockquote>
  
  <p>I'm not starting any new sessions as far as I can see (my code is 90% the same as the first link). Maybe this is a problem with my server? Any ideas?  </p>