diff --git a/lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php b/lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php
index 146dfb5c5..6c095c9e3 100644
--- a/lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php
+++ b/lib/Doctrine/ORM/Internal/Hydration/AbstractHydrator.php
@@ -245,6 +245,9 @@ abstract class AbstractHydrator
             if (isset($cache[$key]['isMetaColumn'])) {
                 if ( ! isset($rowData[$dqlAlias][$cache[$key]['fieldName']]) || $value !== null) {
                     $rowData[$dqlAlias][$cache[$key]['fieldName']] = $value;
+                    if ($cache[$key]['isIdentifier']) {
+                        $nonemptyComponents[$dqlAlias] = true;
+                    }
                 }
 
                 continue;
diff --git a/lib/Doctrine/ORM/Mapping/Builder/ClassMetadataBuilder.php b/lib/Doctrine/ORM/Mapping/Builder/ClassMetadataBuilder.php
index 978a87601..f7d5031cd 100644
--- a/lib/Doctrine/ORM/Mapping/Builder/ClassMetadataBuilder.php
+++ b/lib/Doctrine/ORM/Mapping/Builder/ClassMetadataBuilder.php
@@ -19,7 +19,8 @@
 
 namespace Doctrine\ORM\Mapping\Builder;
 
-use Doctrine\ORM\Mapping\ClassMetadata;
+use Doctrine\ORM\Mapping\ClassMetadata,
+    Doctrine\ORM\Mapping\ClassMetadataInfo;
 
 /**
  * Builder Object for ClassMetadata
@@ -28,18 +29,19 @@ use Doctrine\ORM\Mapping\ClassMetadata;
  * @link        www.doctrine-project.com
  * @since       2.2
  * @author      Benjamin Eberlei <kontakt@beberlei.de>
+ * @author      Guilherme Blanco <guilhermeblanco@hotmail.com>
  */
 class ClassMetadataBuilder
 {
     /**
-     * @var ClassMetadata
+     * @var \Doctrine\ORM\Mapping\ClassMetadataInfo
      */
     private $cm;
 
     /**
-     * @param ClassMetadata $cm
+     * @param \Doctrine\ORM\Mapping\ClassMetadataInfo $cm
      */
-    public function __construct(ClassMetadata $cm)
+    public function __construct(ClassMetadataInfo $cm)
     {
         $this->cm = $cm;
     }
@@ -60,6 +62,7 @@ class ClassMetadataBuilder
     public function setMappedSuperClass()
     {
         $this->cm->isMappedSuperclass = true;
+        
         return $this;
     }
 
@@ -72,6 +75,7 @@ class ClassMetadataBuilder
     public function setCustomRepositoryClass($repositoryClassName)
     {
         $this->cm->setCustomRepositoryClass($repositoryClassName);
+
         return $this;
     }
 
@@ -83,6 +87,7 @@ class ClassMetadataBuilder
     public function setReadOnly()
     {
         $this->cm->markReadOnly();
+
         return $this;
     }
 
@@ -95,6 +100,7 @@ class ClassMetadataBuilder
     public function setTable($name)
     {
         $this->cm->setPrimaryTable(array('name' => $name));
+
         return $this;
     }
 
@@ -110,7 +116,9 @@ class ClassMetadataBuilder
         if (!isset($this->cm->table['indexes'])) {
             $this->cm->table['indexes'] = array();
         }
+
         $this->cm->table['indexes'][$name] = array('columns' => $columns);
+
         return $this;
     }
 
@@ -123,10 +131,12 @@ class ClassMetadataBuilder
      */
     public function addUniqueConstraint(array $columns, $name)
     {
-        if (!isset($this->cm->table['uniqueConstraints'])) {
+        if ( ! isset($this->cm->table['uniqueConstraints'])) {
             $this->cm->table['uniqueConstraints'] = array();
         }
+
         $this->cm->table['uniqueConstraints'][$name] = array('columns' => $columns);
+
         return $this;
     }
 
@@ -143,6 +153,7 @@ class ClassMetadataBuilder
             'name' => $name,
             'query' => $dqlQuery,
         ));
+
         return $this;
     }
 
@@ -154,6 +165,7 @@ class ClassMetadataBuilder
     public function setJoinedTableInheritance()
     {
         $this->cm->setInheritanceType(ClassMetadata::INHERITANCE_TYPE_JOINED);
+
         return $this;
     }
 
@@ -165,6 +177,7 @@ class ClassMetadataBuilder
     public function setSingleTableInheritance()
     {
         $this->cm->setInheritanceType(ClassMetadata::INHERITANCE_TYPE_SINGLE_TABLE);
+
         return $this;
     }
 
@@ -181,12 +194,13 @@ class ClassMetadataBuilder
             'type' => $type,
             'length' => $length,
         ));
+
         return $this;
     }
 
     /**
      * Add a subclass to this inheritance hierachy.
-     * 
+     *
      * @param string $name
      * @param string $class
      * @return ClassMetadataBuilder
@@ -194,6 +208,7 @@ class ClassMetadataBuilder
     public function addDiscriminatorMapClass($name, $class)
     {
         $this->cm->addDiscriminatorMapClass($name, $class);
+
         return $this;
     }
 
@@ -205,6 +220,7 @@ class ClassMetadataBuilder
     public function setChangeTrackingPolicyDeferredExplicit()
     {
         $this->cm->setChangeTrackingPolicy(ClassMetadata::CHANGETRACKING_DEFERRED_EXPLICIT);
+
         return $this;
     }
 
@@ -216,12 +232,13 @@ class ClassMetadataBuilder
     public function setChangeTrackingPolicyNotify()
     {
         $this->cm->setChangeTrackingPolicy(ClassMetadata::CHANGETRACKING_NOTIFY);
+
         return $this;
     }
 
     /**
      * Add lifecycle event
-     * 
+     *
      * @param string $methodName
      * @param string $event
      * @return ClassMetadataBuilder
@@ -229,6 +246,7 @@ class ClassMetadataBuilder
     public function addLifecycleEvent($methodName, $event)
     {
         $this->cm->addLifecycleCallback($methodName, $event);
+
         return $this;
     }
 
@@ -243,7 +261,9 @@ class ClassMetadataBuilder
     {
         $mapping['fieldName'] = $name;
         $mapping['type'] = $type;
+
         $this->cm->mapField($mapping);
+
         return $this;
     }
 
@@ -256,12 +276,18 @@ class ClassMetadataBuilder
      */
     public function createField($name, $type)
     {
-        return new FieldBuilder($this, array('fieldName' => $name, 'type' => $type));
+        return new FieldBuilder(
+            $this,
+            array(
+                'fieldName' => $name,
+                'type'      => $type
+            )
+        );
     }
 
     /**
      * Add a simple many to one association, optionally with the inversed by field.
-     * 
+     *
      * @param string $name
      * @param string $targetEntity
      * @param string|null $inversedBy
@@ -270,9 +296,11 @@ class ClassMetadataBuilder
     public function addManyToOne($name, $targetEntity, $inversedBy = null)
     {
         $builder = $this->createManyToOne($name, $targetEntity);
+
         if ($inversedBy) {
             $builder->setInversedBy($inversedBy);
         }
+
         return $builder->build();
     }
 
@@ -287,19 +315,33 @@ class ClassMetadataBuilder
      */
     public function createManyToOne($name, $targetEntity)
     {
-        return new AssociationBuilder($this, array('fieldName' => $name, 'targetEntity' => $targetEntity), ClassMetadata::MANY_TO_ONE);
+        return new AssociationBuilder(
+            $this,
+            array(
+                'fieldName'    => $name,
+                'targetEntity' => $targetEntity
+            ),
+            ClassMetadata::MANY_TO_ONE
+        );
     }
 
     /**
      * Create OneToOne Assocation Builder
-     * 
+     *
      * @param string $name
      * @param string $targetEntity
      * @return AssociationBuilder
      */
     public function createOneToOne($name, $targetEntity)
     {
-        return new AssociationBuilder($this, array('fieldName' => $name, 'targetEntity' => $targetEntity), ClassMetadata::ONE_TO_ONE);
+        return new AssociationBuilder(
+            $this,
+            array(
+                'fieldName'    => $name,
+                'targetEntity' => $targetEntity
+            ),
+            ClassMetadata::ONE_TO_ONE
+        );
     }
 
     /**
@@ -314,6 +356,7 @@ class ClassMetadataBuilder
     {
         $builder = $this->createOneToOne($name, $targetEntity);
         $builder->setMappedBy($mappedBy);
+
         return $builder->build();
     }
 
@@ -328,9 +371,11 @@ class ClassMetadataBuilder
     public function addOwningOneToOne($name, $targetEntity, $inversedBy = null)
     {
         $builder = $this->createOneToOne($name, $targetEntity);
+
         if ($inversedBy) {
             $builder->setInversedBy($inversedBy);
         }
+
         return $builder->build();
     }
 
@@ -343,12 +388,19 @@ class ClassMetadataBuilder
      */
     public function createManyToMany($name, $targetEntity)
     {
-        return new ManyToManyAssociationBuilder($this, array('fieldName' => $name, 'targetEntity' => $targetEntity), ClassMetadata::MANY_TO_MANY);
+        return new ManyToManyAssociationBuilder(
+            $this,
+            array(
+                'fieldName'    => $name,
+                'targetEntity' => $targetEntity
+            ),
+            ClassMetadata::MANY_TO_MANY
+        );
     }
 
     /**
      * Add a simple owning many to many assocation.
-     * 
+     *
      * @param string $name
      * @param string $targetEntity
      * @param string|null $inversedBy
@@ -357,9 +409,11 @@ class ClassMetadataBuilder
     public function addOwningManyToMany($name, $targetEntity, $inversedBy = null)
     {
         $builder = $this->createManyToMany($name, $targetEntity);
+
         if ($inversedBy) {
             $builder->setInversedBy($inversedBy);
         }
+
         return $builder->build();
     }
 
@@ -375,24 +429,32 @@ class ClassMetadataBuilder
     {
         $builder = $this->createManyToMany($name, $targetEntity);
         $builder->setMappedBy($mappedBy);
+
         return $builder->build();
     }
 
     /**
      * Create a one to many assocation builder
-     * 
+     *
      * @param string $name
      * @param string $targetEntity
      * @return OneToManyAssociationBuilder
      */
     public function createOneToMany($name, $targetEntity)
     {
-        return new OneToManyAssociationBuilder($this, array('fieldName' => $name, 'targetEntity' => $targetEntity), ClassMetadata::ONE_TO_MANY);
+        return new OneToManyAssociationBuilder(
+            $this,
+            array(
+                'fieldName'    => $name,
+                'targetEntity' => $targetEntity
+            ),
+            ClassMetadata::ONE_TO_MANY
+        );
     }
 
     /**
      * Add simple OneToMany assocation.
-     * 
+     *
      * @param string $name
      * @param string $targetEntity
      * @param string $mappedBy
@@ -402,6 +464,7 @@ class ClassMetadataBuilder
     {
         $builder = $this->createOneToMany($name, $targetEntity);
         $builder->setMappedBy($mappedBy);
+
         return $builder->build();
     }
 }
diff --git a/lib/Doctrine/ORM/Query/ResultSetMapping.php b/lib/Doctrine/ORM/Query/ResultSetMapping.php
index 5c6305e25..3c292fda4 100644
--- a/lib/Doctrine/ORM/Query/ResultSetMapping.php
+++ b/lib/Doctrine/ORM/Query/ResultSetMapping.php
@@ -120,7 +120,7 @@ class ResultSetMapping
      *                      results or joined entity results within this ResultSetMapping.
      * @param string $resultAlias The result alias with which the entity result should be
      *                            placed in the result structure.
-     *
+     * @return ResultSetMapping This ResultSetMapping instance.
      * @todo Rename: addRootEntity
      */
     public function addEntityResult($class, $alias, $resultAlias = null)
@@ -131,6 +131,8 @@ class ResultSetMapping
         if ($resultAlias !== null) {
             $this->isMixed = true;
         }
+        
+        return $this;
     }
 
     /**
@@ -141,13 +143,15 @@ class ResultSetMapping
      * @param string $alias The alias of the entity result or joined entity result the discriminator
      *                      column should be used for.
      * @param string $discrColumn The name of the discriminator column in the SQL result set.
-     *
+     * @return ResultSetMapping This ResultSetMapping instance.
      * @todo Rename: addDiscriminatorColumn
      */
     public function setDiscriminatorColumn($alias, $discrColumn)
     {
         $this->discriminatorColumns[$alias] = $discrColumn;
         $this->columnOwnerMap[$discrColumn] = $alias;
+        
+        return $this;
     }
 
     /**
@@ -155,6 +159,7 @@ class ResultSetMapping
      *
      * @param string $alias The alias of an entity result or joined entity result.
      * @param string $fieldName The name of the field to use for indexing.
+     * @return ResultSetMapping This ResultSetMapping instance.
      */
     public function addIndexBy($alias, $fieldName)
     {
@@ -180,17 +185,21 @@ class ResultSetMapping
             throw new \LogicException($message);
         }
         */
+        
+        return $this;
     }
 
     /**
      * Set to index by a scalar result column name
      *
      * @param $resultColumnName
-     * @return void
+     * @return ResultSetMapping This ResultSetMapping instance.
      */
     public function addIndexByScalar($resultColumnName)
     {
         $this->indexByMap['scalars'] = $resultColumnName;
+        
+        return $this;
     }
 
     /**
@@ -198,11 +207,13 @@ class ResultSetMapping
      *
      * @param $alias
      * @param $resultColumnName
-     * @return void
+     * @return ResultSetMapping This ResultSetMapping instance.
      */
     public function addIndexByColumn($alias, $resultColumnName)
     {
         $this->indexByMap[$alias] = $resultColumnName;
+        
+        return $this;
     }
 
     /**
@@ -242,6 +253,7 @@ class ResultSetMapping
      *                               the field $fieldName is defined on a subclass, specify that here.
      *                               If not specified, the field is assumed to belong to the class
      *                               designated by $alias.
+     * @return ResultSetMapping This ResultSetMapping instance.
      * @todo Rename: addField
      */
     public function addFieldResult($alias, $columnName, $fieldName, $declaringClass = null)
@@ -256,6 +268,8 @@ class ResultSetMapping
         if ( ! $this->isMixed && $this->scalarMappings) {
             $this->isMixed = true;
         }
+        
+        return $this;
     }
 
     /**
@@ -265,6 +279,7 @@ class ResultSetMapping
      * @param string $alias The unique alias to use for the joined entity.
      * @param string $parentAlias The alias of the entity result that is the parent of this joined result.
      * @param object $relation The association field that connects the parent entity result with the joined entity result.
+     * @return ResultSetMapping This ResultSetMapping instance.
      * @todo Rename: addJoinedEntity
      */
     public function addJoinedEntityResult($class, $alias, $parentAlias, $relation)
@@ -272,6 +287,8 @@ class ResultSetMapping
         $this->aliasMap[$alias]       = $class;
         $this->parentAliasMap[$alias] = $parentAlias;
         $this->relationMap[$alias]    = $relation;
+        
+        return $this;
     }
 
     /**
@@ -279,6 +296,7 @@ class ResultSetMapping
      *
      * @param string $columnName The name of the column in the SQL result set.
      * @param string $alias The result alias with which the scalar result should be placed in the result structure.
+     * @return ResultSetMapping This ResultSetMapping instance.
      * @todo Rename: addScalar
      */
     public function addScalarResult($columnName, $alias)
@@ -288,6 +306,8 @@ class ResultSetMapping
         if ( ! $this->isMixed && $this->fieldMappings) {
             $this->isMixed = true;
         }
+        
+        return $this;
     }
 
     /**
@@ -439,6 +459,7 @@ class ResultSetMapping
      * @param string $columnName
      * @param string $fieldName
      * @param bool
+     * @return ResultSetMapping This ResultSetMapping instance.
      */
     public function addMetaResult($alias, $columnName, $fieldName, $isIdentifierColumn = false)
     {
@@ -448,5 +469,7 @@ class ResultSetMapping
         if ($isIdentifierColumn) {
             $this->isIdentifierColumn[$alias][$columnName] = true;
         }
+        
+        return $this;
     }
 }
diff --git a/lib/Doctrine/ORM/UnitOfWork.php b/lib/Doctrine/ORM/UnitOfWork.php
index 803e6683c..eb3111fb8 100644
--- a/lib/Doctrine/ORM/UnitOfWork.php
+++ b/lib/Doctrine/ORM/UnitOfWork.php
@@ -1735,7 +1735,7 @@ class UnitOfWork implements PropertyChangedListener
                             $managedCol->initialize();
 
                             // clear and set dirty a managed collection if its not also the same collection to merge from.
-                            if (!$managedCol->isEmpty() && $managedCol != $mergeCol) {
+                            if (!$managedCol->isEmpty() && $managedCol !== $mergeCol) {
                                 $managedCol->unwrap()->clear();
                                 $managedCol->setDirty(true);
 
diff --git a/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1400Test.php b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1400Test.php
index 1639f98bd..2523b5b72 100644
--- a/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1400Test.php
+++ b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1400Test.php
@@ -59,12 +59,7 @@ class DDC1400Test extends \Doctrine\Tests\OrmFunctionalTestCase
         $q->setParameter('activeUser', $user1);
         $articles = $q->getResult();
 
-        var_dump(array_keys($articles[0]->userStates->toArray()));
-
         $this->_em->flush();
-        var_dump($this->_sqlLoggerStack);
-
-
     }
 }
 
diff --git a/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1515Test.php b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1515Test.php
new file mode 100644
index 000000000..9bd3360b8
--- /dev/null
+++ b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC1515Test.php
@@ -0,0 +1,64 @@
+<?php
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+
+/**
+ * @group DDC-1515
+ */
+class DDC1515Test extends \Doctrine\Tests\OrmFunctionalTestCase
+{
+    public function setUp()
+    {
+        parent::setUp();
+        $this->_schemaTool->createSchema(array(
+            $this->_em->getClassMetadata(__NAMESPACE__ . '\\DDC1515Foo'),
+            $this->_em->getClassMetadata(__NAMESPACE__ . '\\DDC1515Bar'),
+        ));
+    }
+
+    public function testIssue()
+    {
+        $bar = new DDC1515Bar();
+        $this->_em->persist($bar);
+        $this->_em->flush();
+
+        $foo = new DDC1515Foo();
+        $foo->bar = $bar;
+        $this->_em->persist($foo);
+        $this->_em->flush();
+        $this->_em->clear();
+
+        $bar = $this->_em->find(__NAMESPACE__ . '\DDC1515Bar', $bar->id);
+        $this->assertInstanceOf(__NAMESPACE__.'\DDC1515Foo', $bar->foo);
+    }
+}
+
+/**
+ * @Entity
+ */
+class DDC1515Foo
+{
+    /**
+     * @OneToOne(targetEntity="DDC1515Bar", inversedBy="foo") @Id
+     */
+    public $bar;
+}
+
+/**
+ * @Entity
+ */
+class DDC1515Bar
+{
+    /**
+     * @Id @Column(type="integer") @GeneratedValue
+     */
+    public $id;
+
+    /**
+     * @OneToOne(targetEntity="DDC1515Foo", mappedBy="bar")
+     */
+    public $foo;
+}
+
+
diff --git a/tests/Doctrine/Tests/ORM/Hydration/ResultSetMappingTest.php b/tests/Doctrine/Tests/ORM/Hydration/ResultSetMappingTest.php
index 562fd4d87..d18c4dbb7 100644
--- a/tests/Doctrine/Tests/ORM/Hydration/ResultSetMappingTest.php
+++ b/tests/Doctrine/Tests/ORM/Hydration/ResultSetMappingTest.php
@@ -14,7 +14,14 @@ require_once __DIR__ . '/../../TestInit.php';
  */
 class ResultSetMappingTest extends \Doctrine\Tests\OrmTestCase
 {
+    /**
+     * @var ResultSetMapping
+     */
     private $_rsm;
+    
+    /**
+     * @var \Doctrine\ORM\EntityManager
+     */
     private $_em;
 
     protected function setUp() {
@@ -56,5 +63,35 @@ class ResultSetMappingTest extends \Doctrine\Tests\OrmTestCase
         $this->assertEquals('username', $this->_rsm->getFieldName('username'));
         $this->assertEquals('name', $this->_rsm->getFieldName('name'));
     }
+    
+    /**
+     * @group DDC-1057
+     * 
+     * Fluent interface test, not a real result set mapping
+     */
+    public function testFluentInterface()
+    {
+        $rms = $this->_rsm;
+        
+        $rms->addEntityResult('Doctrine\Tests\Models\CMS\CmsUser','u')
+            ->addJoinedEntityResult('Doctrine\Tests\Models\CMS\CmsPhonenumber','p','u','phonenumbers')
+            ->addFieldResult('u', 'id', 'id')
+            ->addFieldResult('u', 'name', 'name')
+            ->setDiscriminatorColumn('name', 'name')
+            ->addIndexByColumn('id', 'id')
+            ->addIndexBy('username', 'username')
+            ->addIndexByScalar('sclr0')
+            ->addScalarResult('sclr0', 'numPhones')
+            ->addMetaResult('a', 'user_id', 'user_id');
+        
+        
+        $this->assertTrue($rms->hasIndexBy('id'));
+        $this->assertTrue($rms->isFieldResult('id'));
+        $this->assertTrue($rms->isFieldResult('name'));
+        $this->assertTrue($rms->isScalarResult('sclr0'));
+        $this->assertTrue($rms->isRelation('p'));
+        $this->assertTrue($rms->hasParentAlias('p'));
+        $this->assertTrue($rms->isMixedResult());
+    }
 }