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

1 files changed, 3 insertions, 2 deletions

diff --git a/tests/phpunit/includes/Status/StatusFormatterTest.php b/tests/phpunit/includes/Status/StatusFormatterTest.php
index b16d8064b2a9..289c9c381d41 100644
--- a/tests/phpunit/includes/Status/StatusFormatterTest.php
+++ b/tests/phpunit/includes/Status/StatusFormatterTest.php
@@ -1,6 +1,7 @@
 <?php
 
 use MediaWiki\Context\RequestContext;
+use MediaWiki\Language\MessageParser;
 use MediaWiki\Language\RawMessage;
 use MediaWiki\Message\Message;
 use MediaWiki\Parser\ParserOutput;
@@ -37,8 +38,8 @@ class StatusFormatterTest extends MediaWikiLangTestCase {
 			}
 		};
 
-		$cache = $this->createNoOpMock( MessageCache::class, [ 'parseWithPostprocessing' ] );
-		$cache->method( 'parseWithPostprocessing' )->willReturnCallback(
+		$cache = $this->createNoOpMock( MessageParser::class, [ 'parse' ] );
+		$cache->method( 'parse' )->willReturnCallback(
 			static function ( $text, ...$args ) {
 				$text = html_entity_decode( $text, ENT_QUOTES | ENT_HTML5 );
 				return new ParserOutput( "<p>" . trim( $text ) . "\n</p>" );