title: Warning: spl_object_hash() expects parameter 1 to be object
body: <pre><code>Warning: spl_object_hash() expects parameter 1 to be object, string given in
  /var/www/sitetwo/vendor/doctrine/orm/lib/Doctrine/ORM/UnitOfWork.php line 1367
  </code></pre>
  
  <p>I created MainBlogBundle with <code>Category.php</code> and <code>Product.php</code> using yml mapping annotation via php app/console commands. After using CRUD actions for add/edit/delete/show actions I tried to add a category and after submitting <code>Add category form</code> I get the </p>
  
  <pre><code>Warning: spl_object_hash() expects parameter 1 to be object, string given in
  /var/www/sitetwo/vendor/doctrine/orm/lib/Doctrine/ORM/UnitOfWork.php line 1367
  </code></pre>
  
  <p>I posted my sample code on github and below is the script of database.</p>
  
  <p><code>git@github.com:veerpartap/ProblemSymfony.git</code></p>
  
  <pre><code>/****************************************************************************/
  
  -- phpMyAdmin SQL Dump
  -- version 3.4.10.1deb1
  -- http://www.phpmyadmin.net
  --
  -- Host: localhost
  -- Generation Time: Oct 26, 2013 at 01:56 PM
  -- Server version: 5.5.32
  -- PHP Version: 5.5.3-1+debphp.org~precise+2
  
  SET SQL_MODE="NO_AUTO_VALUE_ON_ZERO";
  SET time_zone = "+00:00";
  
  --
  -- Database: `sitetwo`
  --
  
  -- --------------------------------------------------------
  
  --
  -- Table structure for table `category`
  --
  
  CREATE TABLE IF NOT EXISTS `category` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
  PRIMARY KEY (`id`)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1 ;
  
  -- --------------------------------------------------------
  
  --
  -- Table structure for table `Company`
  --
  
  CREATE TABLE IF NOT EXISTS `Company` (
   `id` int(11) NOT NULL AUTO_INCREMENT,
   `company_name` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
   `address` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
   `owner_name` varchar(150) COLLATE utf8_unicode_ci NOT NULL,
   `status` tinyint(1) NOT NULL,
   `created` datetime NOT NULL,
   PRIMARY KEY (`id`)
  ) ENGINE=InnoDB  DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=3 ;
  
  --
  -- Dumping data for table `Company`
  --
  
   INSERT INTO `Company` (`id`, `company_name`, `address`, `owner_name`, `status`, `created`) VALUES
  (1, 'My First Company', 'Street 5A Sector 85 Chandigarh 1665588', 'Mr. Prateek Kumar', 1, '2013-09-06 00:00:00'),
  (2, 'My Second Private Company', 'Street 34N Sector 89, Chandigarh 165898', 'Mr. Saurabh Shuja', 1, '2013-09-07 00:00:00');
  
  -- --------------------------------------------------------
  
  --
  -- Table structure for table `Post`
  --
  
  CREATE TABLE IF NOT EXISTS `Post` (
   `id` int(11) NOT NULL AUTO_INCREMENT,
   `title` varchar(250) COLLATE utf8_unicode_ci NOT NULL,
   `body` longtext COLLATE utf8_unicode_ci NOT NULL,
   `published` datetime NOT NULL,
   PRIMARY KEY (`id`)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1 ;
  
  -- --------------------------------------------------------
  
  --
  -- Table structure for table `posts`
  --
  
  CREATE TABLE IF NOT EXISTS `posts` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `title` varchar(250) COLLATE utf8_unicode_ci NOT NULL,
  `body` longtext COLLATE utf8_unicode_ci NOT NULL,
  `published` datetime NOT NULL,
   PRIMARY KEY (`id`)
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1 ;
  
  -- --------------------------------------------------------
  
  --
  -- Table structure for table `products`
  --
  
  CREATE TABLE IF NOT EXISTS `products` (
   `id` int(11) NOT NULL AUTO_INCREMENT,
   `category_id` int(11) DEFAULT NULL,
   `name` varchar(100) COLLATE utf8_unicode_ci NOT NULL,
   `price` decimal(10,0) NOT NULL,
   `description` longtext COLLATE utf8_unicode_ci NOT NULL,
   PRIMARY KEY (`id`),
   KEY `IDX_B3BA5A5A12469DE2` (`category_id`)
   ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=1 ;
  
   -- --------------------------------------------------------
  
   --
   -- Table structure for table `User`
   --
  
     CREATE TABLE IF NOT EXISTS `User` (
      `id` int(11) NOT NULL AUTO_INCREMENT,
      `first_name` varchar(150) NOT NULL,
      `last_name` varchar(150) NOT NULL,
     `sex` tinyint(1) DEFAULT NULL,
     `date_of_birth` datetime DEFAULT NULL,
     `education` varchar(10) NOT NULL,
     `mobile` varchar(10) NOT NULL,
     `email` varchar(100) NOT NULL,
     `address` varchar(200) NOT NULL,
     `status` tinyint(1) DEFAULT NULL,
     PRIMARY KEY (`id`)
     ) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=3 ;
  
     --
     -- Dumping data for table `User`
     --
  
     INSERT INTO `User` (`id`, `first_name`, `last_name`, `sex`, `date_of_birth`,  `education`, `mobile`, `email`, `address`, `status`) VALUES
    (1, 'Veerpartap', 'Singh', 1, '2008-11-24 00:00:00', 'MCA', '71505897', 'metveerpartapsingh@gmail.com', 'hl 99 phase 2 sas nagar mohali', 1),
    (2, 'Vicky', 'Sharma', 1, '2008-05-09 00:00:00', 'MCA', '88754257', 'vicky.sharma@gmail.com', 'Village Burari, Jila Nawanshar', 1);
  
    --
    -- Constraints for dumped tables
    --
  
    --
    -- Constraints for table `products`
    --
    ALTER TABLE `products`
    ADD CONSTRAINT `FK_B3BA5A5A12469DE2` FOREIGN KEY (`category_id`) REFERENCES `category` (`id`);
  
   /****************************************************************************/
  </code></pre>