From: Marius Hoch <hoo@online.de>
Date: Wed, 2 Jan 2013 22:18:50 +0000 (+0100)
Subject: (bug 43595) Add a cache version variable to SiteArray
X-Git-Tag: 1.31.0-rc.0~21149^2
X-Git-Url: https://git.cyclocoop.org/%27.WWW_URL.%27admin/?a=commitdiff_plain;h=9f06c90aa0ee966d987073fe9ed09ba0d640c923;p=lhc%2Fweb%2Fwiklou.git

(bug 43595) Add a cache version variable to SiteArray

Added a $cacheVersion variable to SiteArray to prevent problems
on SiteArray format changes due to a Memcached value of the object
being stored in the outdated format. This already caused disruption
on wikidata.org twice.

(This new version isn't tested as I don't have a memcached environment
with me atm.)

Change-Id: Ib290b465276b6be8b8753c27ea3f57d4597ec3c1
---

diff --git a/includes/site/SiteArray.php b/includes/site/SiteArray.php
index 096a17929c..5d2c86b220 100644
--- a/includes/site/SiteArray.php
+++ b/includes/site/SiteArray.php
@@ -27,6 +27,24 @@
  * @author Jeroen De Dauw < jeroendedauw@gmail.com >
  */
 class SiteArray extends GenericArrayObject implements SiteList {
+	/**
+	 * Update this version number when the SiteArray format
+	 * changes in an incompatible way
+	 *
+	 * @since 1.21
+	 *
+	 * @var integer
+	 */
+	const CACHE_VERSION = 1;
+
+	/**
+	 * Version number of the SiteArray format of the currently used object
+	 *
+	 * @since 1.21
+	 *
+	 * @var integer
+	 */
+	public $cacheVersion = self::CACHE_VERSION;
 
 	/**
 	 * Internal site identifiers pointing to their sites offset value.
@@ -213,6 +231,7 @@ class SiteArray extends GenericArrayObject implements SiteList {
 		return array_merge(
 			parent::getSerializationData(),
 			array(
+				'cacheVersion' => self::CACHE_VERSION,
 				'internalIds' => $this->byInternalId,
 				'globalIds' => $this->byGlobalId,
 			)
@@ -231,6 +250,7 @@ class SiteArray extends GenericArrayObject implements SiteList {
 	public function unserialize( $serialization ) {
 		$serializationData = parent::unserialize( $serialization );
 
+		$this->cacheVersion = $serializationData['cacheVersion'];
 		$this->byInternalId = $serializationData['internalIds'];
 		$this->byGlobalId = $serializationData['globalIds'];
 
diff --git a/includes/site/Sites.php b/includes/site/Sites.php
index 135308c8e7..a67d474306 100644
--- a/includes/site/Sites.php
+++ b/includes/site/Sites.php
@@ -99,10 +99,9 @@ class Sites {
 				$cache = wfGetMainCache();
 				$sites = $cache->get( wfMemcKey( 'SiteList' ) );
 
-				if ( is_object( $sites ) ) {
+				if ( is_object( $sites ) && isset( $sites->cacheVersion ) && $sites->cacheVersion === SiteArray::CACHE_VERSION ) {
 					$this->sites = $sites;
-				}
-				else {
+				} else {
 					$this->loadSites();
 				}
 			}