Discard Classification's Entities are discarded after $om->clear

Fix sonata-project/SonataClassificationBundle#60 (sonata-project/SonataClassificationBundle#60)

MediaEventSubscriber caches the root instances of Category.
If the EntityManager is cleared, the instanced are detached
and need to be re-fetched or merged before being persisted again.

I went the easy way and simply discarded the cache.

Listener/ORM/MediaEventSubscriber.php

@@ -36,9 +36,15 @@ public function getSubscribedEvents()
             Events::postUpdate,
             Events::postRemove,
             Events::postPersist,
+            Events::onClear,
         );
     }
 
+    public function onClear()
+    {
+        $this->rootCategories = null;
+    }
+
     /**
      * {@inheritdoc}
      */

Tests/Listener/ORM/MediaEventSubscriberTest.php

@@ -0,0 +1,79 @@
+<?php
+
+/*
+ * This file is part of the Sonata Project package.
+ *
+ * (c) Thomas Rabaix <thomas.rabaix@sonata-project.org>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Sonata\MediaBundle\Tests\Listener\ORM;
+
+use Doctrine\ORM\Events;
+use Sonata\MediaBundle\Listener\ORM\MediaEventSubscriber;
+use Sonata\MediaBundle\Model\Media;
+use Sonata\MediaBundle\Provider\Pool;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * @author Mathieu Lemoine <mlemoine@mlemoine.name>
+ */
+class MediaEventSubscriberTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @see https://github.com/sonata-project/SonataClassificationBundle/issues/60
+     * @see https://github.com/sonata-project/SonataMediaBundle/pull/780
+     */
+    public function testRefetchCategoriesAfterClear()
+    {
+        $provider = $this->getMock('Sonata\\MediaBundle\\Provider\\MediaProviderInterface');
+
+        $pool = $this->getMock('Sonata\\MediaBundle\\Provider\\Pool', array(), array('default'));
+
+        $pool->method('getProvider')->will($this->returnValueMap(array(array('provider', $provider))));
+
+        $category = $this->getMock('Sonata\\ClassificationBundle\\Model\\CategoryInterface');
+
+        $catManager = $this->getMockBuilder('Sonata\\ClassificationBundle\\Entity\\CategoryManager', array('getRootCategories'))
+                           ->disableOriginalConstructor()
+                           ->getMock();
+
+        $container = $this->getMock('Symfony\\Component\\DependencyInjection\\ContainerInterface');
+
+        $container->method('get')->will($this->returnValueMap(array(
+            array('sonata.media.pool', ContainerInterface::EXCEPTION_ON_INVALID_REFERENCE, $pool),
+            array('sonata.classification.manager.category', ContainerInterface::EXCEPTION_ON_INVALID_REFERENCE, $catManager),
+        )));
+
+        $catManager->expects($this->exactly(2))
+                   ->method('getRootCategories')
+                   ->willReturn(array('context' => $category))
+                       ;
+
+        $subscriber = new MediaEventSubscriber($container);
+
+        $this->assertContains(Events::onClear, $subscriber->getSubscribedEvents());
+
+        $media1 = $this->getMock('Sonata\\MediaBundle\\Model\\Media', array('getId', 'getCategory', 'getProvider', 'getContext'));
+        $media1->method('getProvider')->willReturn('provider');
+        $media1->method('getContext')->willReturn('context');
+
+        $args1 = $this->getMock('Doctrine\\Common\\EventArgs', array('getEntity'));
+        $args1->method('getEntity')->willReturn($media1);
+
+        $subscriber->prePersist($args1);
+
+        $subscriber->onClear();
+
+        $media2 = $this->getMock('Sonata\\MediaBundle\\Model\\Media', array('getId', 'getCategory', 'getProvider', 'getContext'));
+        $media2->method('getProvider')->willReturn('provider');
+        $media2->method('getContext')->willReturn('context');
+
+        $args2 = $this->getMock('Doctrine\\Common\\EventArgs', array('getEntity'));
+        $args2->method('getEntity')->willReturn($media2);
+
+        $subscriber->prePersist($args2);
+    }
+}