From 2370dd0b38b71726ab1ba83f1b6d0ef67becaf3b Mon Sep 17 00:00:00 2001
From: Sam Minnee <sam@silverstripe.com>
Date: Tue, 26 May 2009 03:46:04 +0000
Subject: [PATCH] BUGFIX: Fixed edge-case reliability with extension
 application.

git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@77828 467b73ca-7a2a-4603-9d3b-597d59a354a9
---
 core/Extension.php                 | 15 +++++++++++++--
 core/Object.php                    |  2 +-
 core/model/DataObjectDecorator.php | 23 ++++++++++++++---------
 3 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/core/Extension.php b/core/Extension.php
index deb5b1b91..11902448c 100644
--- a/core/Extension.php
+++ b/core/Extension.php
@@ -23,12 +23,23 @@ abstract class Extension extends Object {
 	 * @var DataObject
 	 */
 	protected $owner;
+	
+	/**
+	 * The base class that this extension was applied to; $this->owner must be one of these
+	 * @var DataObject
+	 */
+	protected $ownerBaseClass;
 
 	/**
 	 * Set the owner of this decorator.
-	 * @param DataObject $owner
+	 * @param Object $owner The owner object,
+	 * @param string $ownerBaseClass The base class that the extension is applied to; this may be
+	 * the class of owner, or it may be a parent.  For example, if Versioned was applied to SiteTree,
+	 * and then a Page object was instantiated, $owner would be a Page object, but $ownerBaseClass
+	 * would be 'SiteTree'.
 	 */
-	function setOwner(Object $owner) {
+	function setOwner(Object $owner, $ownerBaseClass = null) {
+		$this->ownerBaseClass = $ownerBaseClass ? $ownerBaseClass : $owner->class;
 		$this->owner = $owner;
 	}
 	
diff --git a/core/Object.php b/core/Object.php
index f49585d6c..2298d2c8f 100755
--- a/core/Object.php
+++ b/core/Object.php
@@ -453,7 +453,7 @@ abstract class Object {
 				// an $extension value can contain parameters as a string,
 				// e.g. "Versioned('Stage','Live')"
 				$instance = eval("return new $extension;");
-				$instance->setOwner($this);
+				$instance->setOwner($this, $class);
 				$this->extension_instances[$instance->class] = $instance;
 			}
 		}
diff --git a/core/model/DataObjectDecorator.php b/core/model/DataObjectDecorator.php
index 58a1262dc..8eb672a78 100755
--- a/core/model/DataObjectDecorator.php
+++ b/core/model/DataObjectDecorator.php
@@ -31,11 +31,13 @@ abstract class DataObjectDecorator extends Extension {
 		'api_access' => false,
 	);
 	
+	private static $extra_statics_loaded = array();
+	
 	/**
 	 * Set the owner of this decorator.
 	 * @param DataObject $owner
 	 */
-	function setOwner(Object $owner) {
+	function setOwner(Object $owner, $ownerBaseClass = null) {
 		if(!($owner instanceof DataObject)) {
 			user_error(sprintf(
 				"DataObjectDecorator->setOwner(): Trying to decorate an object of class '%s' with '%s', 
@@ -46,35 +48,38 @@ abstract class DataObjectDecorator extends Extension {
 			return false;
 		}
 		
-		parent::setOwner($owner);
+		parent::setOwner($owner, $ownerBaseClass);
 	}
 	
 	/**
 	 * Load the extra database fields defined in extraStatics.
 	 */
 	function loadExtraStatics() {
-		// Don't apply DB fields if the parent object has this extension too
-		if(Object::has_extension($this->owner->parentClass(), $this->class)) return;
+		if(!empty(self::$extra_statics_loaded[$this->ownerBaseClass][$this->class])) return;
+		self::$extra_statics_loaded[$this->ownerBaseClass][$this->class] = true;
+
+		// If the extension has been manually applied to a subclass, we should ignore that.
+		if(Object::has_extension(get_parent_class($this->owner), $this->class)) return;
 
 		if($fields = $this->extraStatics()) {
 			foreach($fields as $relation => $newVal) {
 				if(isset(self::$decoratable_statics[$relation])) {
-					$origVal = Object::get_static($this->owner->class, $relation);
+					$origVal = Object::get_static($this->ownerBaseClass, $relation);
 
 					// Array to be merged 
 					if(self::$decoratable_statics[$relation]) {
 						// Can't use add_static_var() here as it would merge the array rather than replacing
-						Object::set_static($this->owner->class, $relation, array_merge((array)$origVal, $newVal));
+						Object::set_static($this->ownerBaseClass, $relation, array_merge((array)$origVal, $newVal));
 
 					// Value to be overwritten
 					} else {
-						Object::set_static ($this->owner->class, $relation, $newVal);
+						Object::set_static ($this->ownerBaseClass, $relation, $newVal);
 					}
 				}
 			}
 			
-			DataObject::$cache_has_own_table[$this->owner->class]       = null;
-			DataObject::$cache_has_own_table_field[$this->owner->class] = null;
+			DataObject::$cache_has_own_table[$this->ownerBaseClass]       = null;
+			DataObject::$cache_has_own_table_field[$this->ownerBaseClass] = null;
 		}
 	}