From 2f401c66aa5e57419aa0884fe602de006edf1e60 Mon Sep 17 00:00:00 2001
From: daniel <dkinzler@wikimedia.org>
Date: Tue, 26 Nov 2019 20:33:10 +0100
Subject: [PATCH] LocalisationCache: Don't instantiate ResourceLoader

When clearing the LocalisationCache, avoid instantiating a ResourceLoader
instance. Doing so introduces a circular dependency among service
instances.

This patch introduces a static method for clearing the MessageBlobStore
without the need for a ResoruceLoader instance.

Bug: T231866
Change-Id: I404e64713fee6a534ba014981cef78af0b91f2aa
(cherry picked from commit 41415deda4c66ba52194c4df51c54c367f1f10b9)
---
 includes/ServiceWiring.php                   |  5 ++++-
 includes/resourceloader/MessageBlobStore.php | 17 +++++++++++++++--
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/includes/ServiceWiring.php b/includes/ServiceWiring.php
index 626c14fc46..a106157130 100644
--- a/includes/ServiceWiring.php
+++ b/includes/ServiceWiring.php
@@ -319,7 +319,10 @@ return [
 			$store,
 			$logger,
 			[ function () use ( $services ) {
-				$services->getResourceLoader()->getMessageBlobStore()->clear();
+				// NOTE: Make sure we use the same cache object that is assigned in the
+				// constructor of the MessageBlobStore class used by ResourceLoader.
+				// T231866: Avoid circular dependency via ResourceLoader.
+				MessageBlobStore::clearGlobalCacheEntry( $services->getMainWANObjectCache() );
 			} ],
 			$services->getLanguageNameUtils()
 		);
diff --git a/includes/resourceloader/MessageBlobStore.php b/includes/resourceloader/MessageBlobStore.php
index b4f0b7c25b..29dc866ecf 100644
--- a/includes/resourceloader/MessageBlobStore.php
+++ b/includes/resourceloader/MessageBlobStore.php
@@ -57,6 +57,10 @@ class MessageBlobStore implements LoggerAwareInterface {
 	public function __construct( ResourceLoader $rl, LoggerInterface $logger = null ) {
 		$this->resourceloader = $rl;
 		$this->logger = $logger ?: new NullLogger();
+
+		// NOTE: when changing this assignment, make sure the code in the instantiator for
+		// LocalisationCache which calls MessageBlobStore::clearGlobalCacheEntry() uses the
+		// same cache object.
 		$this->wanCache = MediaWikiServices::getInstance()->getMainWANObjectCache();
 	}
 
@@ -169,10 +173,19 @@ class MessageBlobStore implements LoggerAwareInterface {
 
 	/**
 	 * Invalidate cache keys for all known modules.
-	 * Called by LocalisationCache after cache is regenerated.
 	 */
 	public function clear() {
-		$cache = $this->wanCache;
+		self::clearGlobalCacheEntry( $this->wanCache );
+	}
+
+	/**
+	 * Invalidate cache keys for all known modules.
+	 *
+	 * Called by LocalisationCache after cache is regenerated.
+	 *
+	 * @param WANObjectCache $cache
+	 */
+	public static function clearGlobalCacheEntry( WANObjectCache $cache ) {
 		// Disable hold-off because:
 		// - LocalisationCache is populated by messages on-disk and don't have DB lag,
 		//   thus there is no need for hold off. We only clear it after new localisation
-- 
2.20.1