diff --git a/lib/Doctrine/ORM/Proxy/ProxyFactory.php b/lib/Doctrine/ORM/Proxy/ProxyFactory.php
index de67e2f86..aa1e6a8e8 100644
--- a/lib/Doctrine/ORM/Proxy/ProxyFactory.php
+++ b/lib/Doctrine/ORM/Proxy/ProxyFactory.php
@@ -25,6 +25,7 @@ use Doctrine\ORM\EntityNotFoundException;
 use Doctrine\Common\Util\ClassUtils;
 use Doctrine\Common\Proxy\Proxy;
 use Doctrine\Common\Proxy\ProxyGenerator;
+use Doctrine\ORM\ORMInvalidArgumentException;
 
 /**
  * This factory is used to create proxy objects for entities at runtime.
@@ -123,6 +124,31 @@ class ProxyFactory
         return $proxy;
     }
 
+    /**
+     * @param \Doctrine\Common\Proxy\Proxy $proxy
+     *
+     * @return \Doctrine\Common\Proxy\Proxy
+     *
+     * @throws \Doctrine\ORM\ORMInvalidArgumentException
+     */
+    public function resetUninitializedProxy(Proxy $proxy)
+    {
+        if ($proxy->__isInitialized()) {
+            throw new ORMInvalidArgumentException('Provided proxy must not be initialized');
+        }
+
+        $className = $this->em->getClassMetadata(get_class($proxy))->getName();
+
+        if ( ! isset($this->definitions[$className])) {
+            $this->initProxyDefinitions($className);
+        }
+
+        $proxy->__setInitializer($this->definitions[$className]['initializer']);
+        $proxy->__setCloner($this->definitions[$className]['cloner']);
+
+        return $proxy;
+    }
+
     /**
      * Generates proxy classes for all given classes.
      *
@@ -179,8 +205,9 @@ class ProxyFactory
      */
     private function initProxyDefinitions($className)
     {
-        $fqcn = ClassUtils::generateProxyClassName($className, $this->proxyNs);
         $classMetadata = $this->em->getClassMetadata($className);
+        $className     = $classMetadata->getName();
+        $fqcn          = ClassUtils::generateProxyClassName($className, $this->proxyNs);
 
         if ( ! class_exists($fqcn, false)) {
             $generator = $this->getProxyGenerator();
diff --git a/lib/Doctrine/ORM/UnitOfWork.php b/lib/Doctrine/ORM/UnitOfWork.php
index 1fa7676bb..35f677fc5 100644
--- a/lib/Doctrine/ORM/UnitOfWork.php
+++ b/lib/Doctrine/ORM/UnitOfWork.php
@@ -1769,7 +1769,8 @@ class UnitOfWork implements PropertyChangedListener
         $managedCopy = $entity;
 
         if ($this->getEntityState($entity, self::STATE_DETACHED) !== self::STATE_MANAGED) {
-            if ($entity instanceof Proxy && ! $entity->__isInitialized__) {
+            if ($entity instanceof Proxy && ! $entity->__isInitialized()) {
+                $this->em->getProxyFactory()->resetUninitializedProxy($entity);
                 $entity->__load();
             }
 
diff --git a/lib/vendor/doctrine-common b/lib/vendor/doctrine-common
index c2b45fdb2..0aa165610 160000
--- a/lib/vendor/doctrine-common
+++ b/lib/vendor/doctrine-common
@@ -1 +1 @@
-Subproject commit c2b45fdb2757492e75abaab119164aaf311cd395
+Subproject commit 0aa165610e2fdd6617e0e2b91c35fedf92aea2f7
diff --git a/tests/Doctrine/Tests/Models/DDC1734/DDC1734Article.php b/tests/Doctrine/Tests/Models/DDC1734/DDC1734Article.php
new file mode 100644
index 000000000..b018da840
--- /dev/null
+++ b/tests/Doctrine/Tests/Models/DDC1734/DDC1734Article.php
@@ -0,0 +1,37 @@
+<?php
+
+namespace Doctrine\Tests\Models\DDC1734;
+
+/**
+ * @Entity
+ */
+class DDC1734Article
+{
+
+    /**
+     * @Id @Column(type="integer")
+     * @GeneratedValue
+     */
+    protected $id;
+
+    /**
+     * @Column(type="string")
+     */
+    protected $name;
+
+    public function __construct($name)
+    {
+        $this->name = $name;
+    }
+
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    public function getName()
+    {
+        return $this->name;
+    }
+
+}
diff --git a/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1734Test.php b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1734Test.php
new file mode 100644
index 000000000..d5748a5aa
--- /dev/null
+++ b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1734Test.php
@@ -0,0 +1,78 @@
+<?php
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+use Doctrine\Tests\Models\DDC1734\DDC1734Article;
+
+require_once __DIR__ . '/../../../TestInit.php';
+
+class DDC1734Test extends \Doctrine\Tests\OrmFunctionalTestCase
+{
+
+    protected function setUp()
+    {
+        $this->useModelSet('ddc1734');
+        parent::setUp();
+    }
+
+    /**
+     * This test is DDC-1734 minus the serialization, i.e. it works
+     * @group DDC-1734
+     */
+    public function testMergeWorksOnNonSerializedProxies()
+    {
+        $article = new DDC1734Article("Foo");
+        $this->_em->persist($article);
+        $this->_em->flush();
+        // Get a proxy of the entity
+        $this->_em->clear();
+        $proxy = $this->getProxy($article);
+        $this->assertInstanceOf('Doctrine\ORM\Proxy\Proxy', $proxy);
+        $this->assertFalse($proxy->__isInitialized__);
+        // Detach
+        $this->_em->detach($proxy);
+        $this->_em->clear();
+        // Merge
+        $proxy = $this->_em->merge($proxy);
+        $this->assertEquals("Foo", $proxy->getName(), "The entity is broken");
+    }
+
+    /**
+     * This test reproduces DDC-1734 which is:
+     * - A non-initialized proxy is detached and serialized (the identifier of the proxy is *not* serialized)
+     * - the object is deserialized and merged (to turn into an entity)
+     * - the entity is broken because it has no identifier and no field defined
+     * @group DDC-1734
+     */
+    public function testMergeWorksOnSerializedProxies()
+    {
+        $article = new DDC1734Article("Foo");
+        $this->_em->persist($article);
+        $this->_em->flush();
+        // Get a proxy of the entity
+        $this->_em->clear();
+        $proxy = $this->getProxy($article);
+        $this->assertInstanceOf('Doctrine\ORM\Proxy\Proxy', $proxy);
+        $this->assertFalse($proxy->__isInitialized());
+        // Detach and serialize
+        $this->_em->detach($proxy);
+        $serializedProxy = serialize($proxy);
+        $this->_em->clear();
+        // Unserialize and merge
+        /** @var $unserializedProxy DDC1734Article */
+        $unserializedProxy = unserialize($serializedProxy);
+        // Merge
+        $unserializedProxy = $this->_em->merge($unserializedProxy);
+        $this->assertEquals("Foo", $unserializedProxy->getName(), "The entity is broken");
+    }
+
+    private function getProxy($object)
+    {
+        $metadataFactory = $this->_em->getMetadataFactory();
+        $identifier      = $metadataFactory->getMetadataFor(get_class($object))->getIdentifierValues($object);
+        $proxyFactory    = $this->_em->getProxyFactory();
+
+        return $proxyFactory->getProxy(get_class($object), $identifier);
+    }
+
+}
\ No newline at end of file
diff --git a/tests/Doctrine/Tests/OrmFunctionalTestCase.php b/tests/Doctrine/Tests/OrmFunctionalTestCase.php
index 715c32a5f..a16cba368 100644
--- a/tests/Doctrine/Tests/OrmFunctionalTestCase.php
+++ b/tests/Doctrine/Tests/OrmFunctionalTestCase.php
@@ -134,6 +134,9 @@ abstract class OrmFunctionalTestCase extends OrmTestCase
             'Doctrine\Tests\Models\DDC117\DDC117Editor',
             'Doctrine\Tests\Models\DDC117\DDC117Link',
         ),
+        'ddc1734' => array(
+            'Doctrine\Tests\Models\DDC1734\DDC1734Article',
+        ),
         'stockexchange' => array(
             'Doctrine\Tests\Models\StockExchange\Bond',
             'Doctrine\Tests\Models\StockExchange\Stock',