Catch catchable fatal errors when formatting echo notifications

Change-Id: Ieaf02ece716802309e85ed0e32a0a15fcd24c50d

controller/NotificationController.php

@@ -327,13 +327,15 @@ class EchoNotificationController {
 
 		$eventType = $event->getType();
 
+		$res = '';
 		if ( isset( $wgEchoNotifications[$eventType] ) ) {
+			set_error_handler( array( __CLASS__, 'formatterErrorHandler' ), -1 );
 			try {
 				$params = $wgEchoNotifications[$eventType];
 				$notifier = EchoNotificationFormatter::factory( $params );
 				$notifier->setOutputFormat( $format );
 
-				return $notifier->format( $event, $user, $type );
+				$res = $notifier->format( $event, $user, $type );
 			} catch ( Exception $e ) {
 				$meta = array(
 					'id' => $event->getId(),
@@ -344,11 +346,38 @@ class EchoNotificationController {
 				);
 				wfDebugLog( __CLASS__, __FUNCTION__ . ": Error formatting " . FormatJson::encode( $meta ) );
 				MWExceptionHandler::logException( $e );
-				return '';
 			}
+			restore_error_handler();
 		}
 
-		return Xml::tags( 'span', array( 'class' => 'error' ),
+		if ( $res ) {
-			wfMessage( 'echo-error-no-formatter', $event->getType() )->escaped() );
+			return $res;
+		} else {
+			return Xml::tags( 'span', array( 'class' => 'error' ),
+				wfMessage( 'echo-error-no-formatter', $event->getType() )->escaped() );
+		}
+	}
+
+	/**
+	 * INTERNAL.  Must be public to be callable by the php error handling methods.
+	 *
+	 * Converts E_RECOVERABLE_ERROR, such as passing null to a method expecting 
+	 * a non-null object, into exceptions.
+	 */
+	public static function formatterErrorHandler( $errno, $errstr, $errfile, $errline ) {
+		if ( $errno !== E_RECOVERABLE_ERROR ) {
+			return false;
+		}
+
+		throw new CatchableFatalErrorException( $errno, $errstr, $errfile, $errline );
+	}
+}
+
+class CatchableFatalErrorException extends MWException {
+	public function __construct( $errno, $errstr, $errfile, $errline ) {
+		parent::__construct( "Catchable fatal error: $errstr", $errno );
+		// inherited protected variables from \Exception
+		$this->file = $errfile;
+		$this->line = $errline;
 	}
 }

tests/NotificationFormatterTest.php

@@ -206,19 +206,15 @@ class EchoNotificationFormatterTest extends MediaWikiTestCase {
 		$this->assertContains( $expect, $this->format( $event, 'html' ) );
 	}
 
-	protected function format( EchoEvent $event, $format, $user = false, $type = 'web', array $params = array() ) {
+	protected function format( EchoEvent $event, $format, $user = false, $type = 'web' ) {
 		global $wgEchoNotifications;
 
-		$params += $wgEchoNotifications[ $event->getType() ];
-		$formatter = EchoNotificationFormatter::factory( $params );
-		$formatter->setOutputFormat( $format );
-
 		if ( $user === false ) {
 			$user = User::newFromName('Notification-formatter-test');
 		}
 
 		// Notification users can not be anonymous, use a fake user id
-		return $formatter->format( $event, $user, $type );
+		return EchoNotificationController::formatNotification( $event, $user, $format, $type );
 	}
 
 	protected function mockEvent( $type, array $extra = array(), Revision $rev = null ) {