Index: languages/Language.php
===================================================================
--- languages/Language.php	(revision 93959)
+++ languages/Language.php	(working copy)
@@ -148,9 +148,6 @@
 	 * @return Language
 	 */
 	protected static function newFromCode( $code ) {
-		global $IP;
-		static $recursionLevel = 0;
-
 		// Protect against path traversal below
 		if ( !Language::isValidCode( $code )
 			|| strcspn( $code, ":/\\\000" ) !== strlen( $code ) )
@@ -166,35 +163,31 @@
 			return $lang;
 		}
 
-		if ( $code == 'en' ) {
-			$class = 'Language';
-		} else {
-			$class = 'Language' . str_replace( '-', '_', ucfirst( $code ) );
-			if ( !defined( 'MW_COMPILED' ) ) {
-				// Preload base classes to work around APC/PHP5 bug
-				if ( file_exists( "$IP/languages/classes/$class.deps.php" ) ) {
-					include_once( "$IP/languages/classes/$class.deps.php" );
-				}
-				if ( file_exists( "$IP/languages/classes/$class.php" ) ) {
-					include_once( "$IP/languages/classes/$class.php" );
-				}
-			}
+		// Check if there is a language class for the code
+		$class = self::classFromCode( $code );
+		self::preloadLanguageClass( $class );
+		if ( MWInit::classExists( $class ) ) {
+			$lang = Language::newFromCode( $code );
+			return $lang;
 		}
 
-		if ( $recursionLevel > 5 ) {
-			throw new MWException( "Language fallback loop detected when creating class $class\n" );
+		// Keep trying the fallback list until we find an existing class
+		$fallbacks = Language::getFallbacskFor( $code );
+		foreach ( $fallbacks as $fallbackCode ) {
+			if ( !Language::isValidBuiltInCode( $fallbackCode ) ) {
+				throw new MWException( "Invalid fallback '$fallbackCode' in fallback sequence for '$code'" );
+			}
+
+			$class = self::classFromCode( $fallbackCode );
+			self::preloadLanguageClass( $class );
+			if ( MWInit::classExists( $class ) ) {
+				$lang = Language::newFromCode( $fallbackCode );
+				$lang->setCode( $code );
+				return $lang;
+			}
 		}
 
-		if ( !MWInit::classExists( $class ) ) {
-			$fallback = Language::getFallbackFor( $code );
-			++$recursionLevel;
-			$lang = Language::newFromCode( $fallback );
-			--$recursionLevel;
-			$lang->setCode( $code );
-		} else {
-			$lang = new $class;
-		}
-		return $lang;
+		throw new MWException( "Invalid fallback sequence for language '$code'" );
 	}
 
 	/**
@@ -224,6 +217,32 @@
 		return preg_match( '/^[a-z0-9-]*$/i', $code );
 	}
 
+	public static function classFromCode( $code ) {
+		if ( $code == 'en' ) {
+			return 'Language';
+		} else {
+			return 'Language' . str_replace( '-', '_', ucfirst( $code ) );
+		}
+	}
+
+	public static function preloadLanguageClass( $class ) {
+		global $IP;
+
+		if ( $class === 'Language' ) {
+			return;
+		}
+
+		if ( !defined( 'MW_COMPILED' ) ) {
+			// Preload base classes to work around APC/PHP5 bug
+			if ( file_exists( "$IP/languages/classes/$class.deps.php" ) ) {
+				include_once( "$IP/languages/classes/$class.deps.php" );
+			}
+			if ( file_exists( "$IP/languages/classes/$class.php" ) ) {
+				include_once( "$IP/languages/classes/$class.php" );
+			}
+		}
+	}
+
 	/**
 	 * Get the LocalisationCache instance
 	 *
@@ -2437,14 +2451,7 @@
 	 */
 	function addMagicWordsByLang( $newWords ) {
 		$code = $this->getCode();
-		$fallbackChain = array();
-		while ( $code && !in_array( $code, $fallbackChain ) ) {
-			$fallbackChain[] = $code;
-			$code = self::getFallbackFor( $code );
-		}
-		if ( !in_array( 'en', $fallbackChain ) ) {
-			$fallbackChain[] = 'en';
-		}
+		$fallbackChain = self::getFallbacskFor( $code );
 		$fallbackChain = array_reverse( $fallbackChain );
 		foreach ( $fallbackChain as $code ) {
 			if ( isset( $newWords[$code] ) ) {
@@ -3304,11 +3311,29 @@
 			// Shortcut
 			return false;
 		} else {
-			return self::getLocalisationCache()->getItem( $code, 'fallback' );
+			$fallbacks = self::getFallbacskFor( $code );
+			// Thank you, php
+			$first = array_shift( $fallbacks );
+			return $first;
 		}
 	}
 
 	/**
+	 * Get the ordered list of fallback languages.
+	 *
+	 * @param $code string Language code
+	 * @return array
+	 */
+	static function getFallbacskFor( $code ) {
+		if ( $code === 'en' ) {
+			// Shortcut
+			return array();
+		} else {
+			return (array) self::getLocalisationCache()->getItem( $code, 'fallback' );
+		}
+	}
+
+	/**
 	 * Get all messages for a given language
 	 * WARNING: this may take a long time
 	 *