From 69aecc2eeae01dc94e40785fbfb9dd11e5b1c6b4 Mon Sep 17 00:00:00 2001
From: Max Semenik <maxsem.wiki@gmail.com>
Date: Mon, 30 Apr 2018 17:35:08 -0700
Subject: [PATCH] Don't initialize MediaWikiServices before extensions have
 been loaded

Bug: T153256
Bug: T190425
Change-Id: I749f66d13a8c8a8ae4a83661b83c56f0db74a187
---
 includes/ServiceWiring.php                  | 20 ++------------------
 includes/objectcache/ObjectCache.php        | 17 +++++++++++++++++
 includes/registration/ExtensionRegistry.php |  7 ++++---
 3 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/includes/ServiceWiring.php b/includes/ServiceWiring.php
index f97d60df02..ee92cbfecf 100644
--- a/includes/ServiceWiring.php
+++ b/includes/ServiceWiring.php
@@ -404,24 +404,8 @@ return [
 	},
 
 	'LocalServerObjectCache' => function ( MediaWikiServices $services ) {
-		$mainConfig = $services->getMainConfig();
-
-		if ( function_exists( 'apc_fetch' ) ) {
-			$id = 'apc';
-		} elseif ( function_exists( 'apcu_fetch' ) ) {
-			$id = 'apcu';
-		} elseif ( function_exists( 'wincache_ucache_get' ) ) {
-			$id = 'wincache';
-		} else {
-			$id = CACHE_NONE;
-		}
-
-		if ( !isset( $mainConfig->get( 'ObjectCaches' )[$id] ) ) {
-			throw new UnexpectedValueException(
-				"Cache type \"$id\" is not present in \$wgObjectCaches." );
-		}
-
-		return \ObjectCache::newFromParams( $mainConfig->get( 'ObjectCaches' )[$id] );
+		$cacheId = \ObjectCache::detectLocalServerCache();
+		return \ObjectCache::newFromId( $cacheId );
 	},
 
 	'VirtualRESTServiceClient' => function ( MediaWikiServices $services ) {
diff --git a/includes/objectcache/ObjectCache.php b/includes/objectcache/ObjectCache.php
index a6f55e6026..c384032220 100644
--- a/includes/objectcache/ObjectCache.php
+++ b/includes/objectcache/ObjectCache.php
@@ -413,4 +413,21 @@ class ObjectCache {
 		self::$instances = [];
 		self::$wanInstances = [];
 	}
+
+	/**
+	 * Detects which local server cache library is present and returns a configuration for it
+	 * @since 1.32
+	 *
+	 * @return int|string Index to cache in $wgObjectCaches
+	 */
+	public static function detectLocalServerCache() {
+		if ( function_exists( 'apc_fetch' ) ) {
+			return 'apc';
+		} elseif ( function_exists( 'apcu_fetch' ) ) {
+			return 'apcu';
+		} elseif ( function_exists( 'wincache_ucache_get' ) ) {
+			return 'wincache';
+		}
+		return CACHE_NONE;
+	}
 }
diff --git a/includes/registration/ExtensionRegistry.php b/includes/registration/ExtensionRegistry.php
index b000dc11b1..b34a123635 100644
--- a/includes/registration/ExtensionRegistry.php
+++ b/includes/registration/ExtensionRegistry.php
@@ -1,7 +1,5 @@
 <?php
 
-use MediaWiki\MediaWikiServices;
-
 /**
  * ExtensionRegistry class
  *
@@ -142,7 +140,10 @@ class ExtensionRegistry {
 		// We use a try/catch because we don't want to fail here
 		// if $wgObjectCaches is not configured properly for APC setup
 		try {
-			$cache = MediaWikiServices::getInstance()->getLocalServerObjectCache();
+			// Don't use MediaWikiServices here to prevent instantiating it before extensions have
+			// been loaded
+			$cacheId = ObjectCache::detectLocalServerCache();
+			$cache = ObjectCache::newFromId( $cacheId );
 		} catch ( MWException $e ) {
 			$cache = new EmptyBagOStuff();
 		}
-- 
2.20.1