code: public function editAction(Request $request, Post $post)
      {
          if(is_object($post->getPublished()) && $post->getPublished()->format('dmY') == '3011-0001'){
              $post->setPublished(null);
          }
          $deleteForm = $this->createDeleteForm($post);
          $editForm = $this->createForm('BlogBundle\Form\PostType', $post, array('translator' => $this->get('translator') ));
          $editForm->handleRequest($request);
  
          if ($editForm->isSubmitted() && $editForm->isValid()) {
              $em = $this->getDoctrine()->getManager();
              $em->persist($post);
              $em->flush();
  
              $this->get('session')->getFlashBag()->add('success', 'post.edited');
              
              return $this->redirectToRoute('blog_post_index');
          }
  
          return array(
              'entity' => $post,
              'edit_form' => $editForm->createView(),
              'delete_form' => $deleteForm->createView(),
          );
      }
docs: Displays a form to edit an existing Post entity.
  
  @Route("/{id}/edit")
  @Method({"GET", "POST"})
  @Template()
  @I18nDoctrine