From 1cb8d790b64f542406a576b878d67abe284e7275 Mon Sep 17 00:00:00 2001
From: Marco Pivetta <ocramius@gmail.com>
Date: Thu, 7 Jul 2016 20:29:00 +0200
Subject: [PATCH] Disallowing `null` as part of the entity identifier

---
 lib/Doctrine/ORM/UnitOfWork.php | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/Doctrine/ORM/UnitOfWork.php b/lib/Doctrine/ORM/UnitOfWork.php
index c54d97a0b..23bee1401 100644
--- a/lib/Doctrine/ORM/UnitOfWork.php
+++ b/lib/Doctrine/ORM/UnitOfWork.php
@@ -1398,12 +1398,13 @@ class UnitOfWork implements PropertyChangedListener
     public function addToIdentityMap($entity)
     {
         $classMetadata = $this->em->getClassMetadata(get_class($entity));
-        $idHash        = implode(' ', $this->entityIdentifiers[spl_object_hash($entity)]);
+        $identifier    = $this->entityIdentifiers[spl_object_hash($entity)];
 
-        if ($idHash === '') {
+        if (in_array(null, $identifier, true)) {
             throw ORMInvalidArgumentException::entityWithoutIdentity($classMetadata->name, $entity);
         }
 
+        $idHash    = implode(' ', $identifier);
         $className = $classMetadata->rootEntityName;
 
         if (isset($this->identityMap[$className][$idHash])) {