[2.0] DDC-414 - Changed semantics of preUpdate Event to allow only changes to the entity changeset, not the internal state of the entity anymore.

UPGRADE_TO_2_0

@@ -19,6 +19,13 @@ mapped fields inside PHP easily. Upon persist() invocation these values are save
 The 'inheritance-type' attribute changed to take last bit of ClassMetadata constant names, i.e.
 NONE, SINGLE_TABLE, INHERITANCE_TYPE_JOINED
 
+## Change of PreUpdate Event Listener
+
+Event Listeners listening to the 'preUpdate' event can only affect the primitive values of entity changesets
+by using the API on the `PreUpdateEventArgs` instance passed to the preUpdate listener method. Any changes
+to the state of the entitys properties won't affect the database UPDATE statement anymore. This gives drastic
+performance benefits for the preUpdate event.
+
 # Upgrade from 2.0-ALPHA3 to 2.0-ALPHA4
 
 ## CLI Controller changes

lib/Doctrine/ORM/Event/PreUpdateEventArgs.php

@@ -0,0 +1,98 @@
+<?php
+
+namespace Doctrine\ORM\Event;
+
+use Doctrine\Common\EventArgs,
+    Doctrine\ORM\EntityManager;
+
+/**
+ * Class that holds event arguments for a preInsert/preUpdate event.
+ *
+ * @author Roman Borschel <roman@code-factory.org>
+ * @author Benjamin Eberlei <kontakt@beberlei.de>
+ * @since 2.0
+ */
+class PreUpdateEventArgs extends LifecycleEventArgs
+{
+    /**
+     * @var array
+     */
+    private $_entityChangeSet;
+
+    /**
+     *
+     * @param object $entity
+     * @param EntityManager $em
+     * @param array $changeSet
+     */
+    public function __construct($entity, $em, array &$changeSet)
+    {
+        parent::__construct($entity, $em);
+        $this->_entityChangeSet = &$changeSet;
+    }
+
+    public function getEntityChangeSet()
+    {
+        return $this->_entityChangeSet;
+    }
+
+    /**
+     * Field has a changeset?
+     *
+     * @return bool
+     */
+    public function hasChangedField($field)
+    {
+        return isset($this->_entityChangeSet[$field]);
+    }
+
+    /**
+     * Get the old value of the changeset of the changed field.
+     * 
+     * @param  string $field
+     * @return mixed
+     */
+    public function getOldValue($field)
+    {
+    	$this->_assertValidField($field);
+
+        return $this->_entityChangeSet[$field][0];
+    }
+
+    /**
+     * Get the new value of the changeset of the changed field.
+     *
+     * @param  string $field
+     * @return mixed
+     */
+    public function getNewValue($field)
+    {
+        $this->_assertValidField($field);
+
+        return $this->_entityChangeSet[$field][1];
+    }
+
+    /**
+     * Set the new value of this field.
+     * 
+     * @param string $field
+     * @param mixed $value
+     */
+    public function setNewValue($field, $value)
+    {
+        $this->_assertValidField($field);
+
+        $this->_entityChangeSet[$field][1] = $value;
+    }
+
+    private function _assertValidField($field)
+    {
+    	if (!isset($this->_entityChangeSet[$field])) {
+            throw new \InvalidArgumentException(
+                "Field '".$field."' is not a valid field of the entity ".
+                "'".get_class($this->getEntity())."' in PreInsertUpdateEventArgs."
+            );
+        }
+    }
+}
+

lib/Doctrine/ORM/UnitOfWork.php

@@ -752,16 +752,14 @@ class UnitOfWork implements PropertyChangedListener
                 
                 if ($hasPreUpdateLifecycleCallbacks) {
                     $class->invokeLifecycleCallbacks(Events::preUpdate, $entity);
-                    if ( ! $hasPreUpdateListeners) {
-                        // Need to recompute entity changeset to detect changes made in the callback.
-                        $this->recomputeSingleEntityChangeSet($class, $entity);
-                    }
-                }
-                if ($hasPreUpdateListeners) {
-                    $this->_evm->dispatchEvent(Events::preUpdate, new LifecycleEventArgs($entity, $this->_em));
-                    // Need to recompute entity changeset to detect changes made in the listener.
                     $this->recomputeSingleEntityChangeSet($class, $entity);
                 }
+                
+                if ($hasPreUpdateListeners) {
+                    $this->_evm->dispatchEvent(Events::preUpdate, new Event\PreUpdateEventArgs(
+                        $entity, $this->_em, $this->_entityChangeSets[$oid])
+                    );
+                }
 
                 $persister->update($entity);
                 unset($this->_entityUpdates[$oid]);

tests/Doctrine/Tests/ORM/Functional/LifecycleCallbackTest.php

@@ -1,6 +1,7 @@
 <?php
 
 namespace Doctrine\Tests\ORM\Functional;
+use Doctrine\ORM\Event\PreUpdateEventArgs;
 
 require_once __DIR__ . '/../../TestInit.php';
 
@@ -111,6 +112,32 @@ class LifecycleCallbackTest extends \Doctrine\Tests\OrmFunctionalTestCase
         $childMeta = $this->_em->getClassMetadata(__NAMESPACE__ . '\LifecycleCallbackChildEntity');
         $this->assertEquals(array('prePersist' => array(0 => 'doStuff')), $childMeta->lifecycleCallbacks);
     }
+
+    public function testLifecycleListener_ChangeUpdateChangeSet()
+    {
+        $listener = new LifecycleListenerPreUpdate;
+        $this->_em->getEventManager()->addEventListener(array('preUpdate'), $listener);
+
+        $user = new LifecycleCallbackTestUser;
+        $user->setName('Bob');
+        $user->setValue('value');
+        $this->_em->persist($user);
+        $this->_em->flush();
+        $this->_em->clear();
+
+        $dql = "SELECT u FROM Doctrine\Tests\ORM\Functional\LifecycleCallbackTestUser u WHERE u.name = 'Bob'";
+        $bob = $this->_em->createQuery($dql)->getSingleResult();
+        $bob->setName('Alice');
+
+        $this->_em->flush(); // preUpdate reverts Alice to Bob
+        $this->_em->clear();
+
+        $this->_em->getEventManager()->removeEventListener(array('preUpdate'), $listener);
+
+        $bob = $this->_em->createQuery($dql)->getSingleResult();
+
+        $this->assertEquals('Bob', $bob->getName());
+    }
 }
 
 /** @Entity @HasLifecycleCallbacks */
@@ -219,3 +246,11 @@ class LifecycleCallbackChildEntity extends LifecycleCallbackParentEntity {
     /** @Id @Column(type="integer") @GeneratedValue */
     private $id;
 }
+
+class LifecycleListenerPreUpdate
+{
+    public function preUpdate(PreUpdateEventArgs $eventArgs)
+    {
+        $eventArgs->setNewValue('name', 'Bob');
+    }
+}