Change the test listener than layers on second-level-caching so that it is more conservative, only turning on caching-associations when it knows the target entity is cache-able.

tests/Doctrine/Tests/EventListener/CacheMetadataListener.php

@@ -3,33 +3,74 @@
 namespace Doctrine\Tests\EventListener;
 
 use Doctrine\Common\Persistence\Event\LoadClassMetadataEventArgs;
+use Doctrine\Common\Persistence\ObjectManager;
+use Doctrine\ORM\EntityManager;
 use Doctrine\ORM\Mapping\ClassMetadata;
 
 class CacheMetadataListener
 {
+
+    /**
+     * Tracks which entities we have already forced caching enabled on. This is
+     * important to avoid some potential infinite-recursion issues.
+     * @var array
+     */
+    protected $enabledItems = array();
+
     /**
      * @param \Doctrine\Common\Persistence\Event\LoadClassMetadataEventArgs $event
      */
     public function loadClassMetadata(LoadClassMetadataEventArgs $event)
     {
         $metadata = $event->getClassMetadata();
-        $cache    = array(
+        $em = $event->getObjectManager();
-            'usage' => ClassMetadata::CACHE_USAGE_NONSTRICT_READ_WRITE
-        );
 
         /** @var $metadata \Doctrine\ORM\Mapping\ClassMetadata */
         if (strstr($metadata->name, 'Doctrine\Tests\Models\Cache')) {
             return;
         }
 
+        if( ! $em instanceof EntityManager){
+            return;
+        }
+
+        $this->enableCaching($metadata, $em);
+    }
+
+    /**
+     * @param ClassMetadata $metadata
+     * @param EntityManager $em
+     */
+    protected function enableCaching(ClassMetadata $metadata, EntityManager $em){
+
+        if(array_key_exists($metadata->getName(), $this->enabledItems)){
+            return; // Already handled in the past
+        }
+
+        $cache    = array(
+            'usage' => ClassMetadata::CACHE_USAGE_NONSTRICT_READ_WRITE
+        );
+
         if ($metadata->isVersioned) {
             return;
         }
 
         $metadata->enableCache($cache);
 
+        $this->enabledItems[$metadata->getName()] = $metadata;
+
+        /*
+         * Only enable association-caching when the target has already been
+         * given caching settings
+         */
         foreach ($metadata->associationMappings as $mapping) {
-            $metadata->enableAssociationCache($mapping['fieldName'], $cache);
+
+            $targetMeta = $em->getClassMetadata($mapping['targetEntity']);
+            $this->enableCaching($targetMeta, $em);
+
+            if(array_key_exists($targetMeta->getName(), $this->enabledItems)){
+                $metadata->enableAssociationCache($mapping['fieldName'], $cache);
+            }
         }
     }
 }