Split MessageParser out of MessageCache

MessageCache has enough to do without also being a parser. Split a
MessageParser class out of MessageCache and make it a service.

* MessageCache::parseWithPostprocessing() becomes MessageParser::parse()
  because every caller wants postprocessing so it makes sense to use the
  shorter name for this.
* MessageCache::parse() becomes MessageParser
  ::parseWithoutPostprocessing(). I changed the return type from
  ParserOutput|string to ParserOutput, which is a followup to
  I8a1fa84e650d920d07d74722d8059d5afeedec6b. Narrowing the return type
  does not break b/c so it is possible to make this change for both
  variants.
* In the new methods, a null title is always a convenience alias for a
  placeholder title (Special:Badtitle). This reflects the convention in
  Parser::setPage(). The old MessageCache::parse() retains its b/c
  fallback to $wgTitle. MessageCache::transform() had the potential to
  fall back to the title used in the previous call, a fragile mechanism
  which I removed without deprecation.
* For consistency, allow a string language in all new methods.
* In EmailNotification, clean up an early attempt at global state
  avoidance.

Change-Id: I05ab21508d5f8394189fd41ac6a2254ac0e0d785

3 files changed, 8 insertions, 9 deletions

diff --git a/includes/specials/SpecialExpandTemplates.php b/includes/specials/SpecialExpandTemplates.php
index aadf89286b4e..e7bc4e944776 100644
--- a/includes/specials/SpecialExpandTemplates.php
+++ b/includes/specials/SpecialExpandTemplates.php
@@ -133,7 +133,6 @@ class SpecialExpandTemplates extends SpecialPage {
 			$rawhtml = MediaWikiServices::getInstance()->getDefaultOutputPipeline()
 				->run( $pout, $options, [ 'enableSectionEditLinks' => false ] )->getContentHolderText();
 			if ( $generateRawHtml && $rawhtml !== '' ) {
-				// @phan-suppress-next-line SecurityCheck-DoubleEscaped Wanted here to display the html
 				$out->addHTML( $this->makeOutput( $rawhtml, 'expand_templates_html_output' ) );
 			}
 
diff --git a/includes/specials/SpecialRecentChanges.php b/includes/specials/SpecialRecentChanges.php
index 3c9544238fc7..e3796c1d849e 100644
--- a/includes/specials/SpecialRecentChanges.php
+++ b/includes/specials/SpecialRecentChanges.php
@@ -29,6 +29,7 @@ use MediaWiki\ChangeTags\ChangeTagsStore;
 use MediaWiki\Context\IContextSource;
 use MediaWiki\Html\FormOptions;
 use MediaWiki\Html\Html;
+use MediaWiki\Language\MessageParser;
 use MediaWiki\MainConfigNames;
 use MediaWiki\MediaWikiServices;
 use MediaWiki\SpecialPage\ChangesListSpecialPage;
@@ -39,7 +40,6 @@ use MediaWiki\User\UserIdentityUtils;
 use MediaWiki\Utils\MWTimestamp;
 use MediaWiki\Watchlist\WatchedItemStoreInterface;
 use MediaWiki\Xml\Xml;
-use MessageCache;
 use OOUI\ButtonWidget;
 use OOUI\HtmlSnippet;
 use RecentChange;
@@ -59,7 +59,7 @@ class SpecialRecentChanges extends ChangesListSpecialPage {
 	private $watchlistFilterGroupDefinition;
 
 	private WatchedItemStoreInterface $watchedItemStore;
-	private MessageCache $messageCache;
+	private MessageParser $messageParser;
 	private UserOptionsLookup $userOptionsLookup;
 
 	/** @var int */
@@ -68,7 +68,7 @@ class SpecialRecentChanges extends ChangesListSpecialPage {
 
 	public function __construct(
 		?WatchedItemStoreInterface $watchedItemStore = null,
-		?MessageCache $messageCache = null,
+		?MessageParser $messageParser = null,
 		?UserOptionsLookup $userOptionsLookup = null,
 		?ChangeTagsStore $changeTagsStore = null,
 		?UserIdentityUtils $userIdentityUtils = null,
@@ -84,7 +84,7 @@ class SpecialRecentChanges extends ChangesListSpecialPage {
 			$tempUserConfig ?? $services->getTempUserConfig()
 		);
 		$this->watchedItemStore = $watchedItemStore ?? $services->getWatchedItemStore();
-		$this->messageCache = $messageCache ?? $services->getMessageCache();
+		$this->messageParser = $messageParser ?? $services->getMessageParser();
 		$this->userOptionsLookup = $userOptionsLookup ?? $services->getUserOptionsLookup();
 		$this->changeTagsStore = $changeTagsStore ?? $services->getChangeTagsStore();
 
@@ -724,7 +724,7 @@ class SpecialRecentChanges extends ChangesListSpecialPage {
 			// Parse the message in this weird ugly way to preserve the ability to include interlanguage
 			// links in it (T172461). In the future when T66969 is resolved, perhaps we can just use
 			// $message->parse() instead. This code is copied from Message::parseText().
-			$parserOutput = $this->messageCache->parseWithPostprocessing(
+			$parserOutput = $this->messageParser->parse(
 				$message->plain(),
 				$this->getPageTitle(),
 				/*linestart*/ true,
diff --git a/includes/specials/SpecialRecentChangesLinked.php b/includes/specials/SpecialRecentChangesLinked.php
index bc0a90e9ad79..693b738ec92c 100644
--- a/includes/specials/SpecialRecentChangesLinked.php
+++ b/includes/specials/SpecialRecentChangesLinked.php
@@ -23,6 +23,7 @@ namespace MediaWiki\Specials;
 use MediaWiki\ChangeTags\ChangeTagsStore;
 use MediaWiki\Html\FormOptions;
 use MediaWiki\Html\Html;
+use MediaWiki\Language\MessageParser;
 use MediaWiki\MainConfigNames;
 use MediaWiki\Title\Title;
 use MediaWiki\User\Options\UserOptionsLookup;
@@ -30,7 +31,6 @@ use MediaWiki\User\TempUser\TempUserConfig;
 use MediaWiki\User\UserIdentityUtils;
 use MediaWiki\Watchlist\WatchedItemStoreInterface;
 use MediaWiki\Xml\Xml;
-use MessageCache;
 use RecentChange;
 use SearchEngineFactory;
 use Wikimedia\Rdbms\SelectQueryBuilder;
@@ -51,7 +51,7 @@ class SpecialRecentChangesLinked extends SpecialRecentChanges {
 
 	public function __construct(
 		WatchedItemStoreInterface $watchedItemStore,
-		MessageCache $messageCache,
+		MessageParser $messageParser,
 		UserOptionsLookup $userOptionsLookup,
 		SearchEngineFactory $searchEngineFactory,
 		ChangeTagsStore $changeTagsStore,
@@ -60,7 +60,7 @@ class SpecialRecentChangesLinked extends SpecialRecentChanges {
 	) {
 		parent::__construct(
 			$watchedItemStore,
-			$messageCache,
+			$messageParser,
 			$userOptionsLookup,
 			$changeTagsStore,
 			$userIdentityUtils,