Return true on success, not just false on failure. A bit of documentation as well :-)

includes/AutoLoader.php

@@ -463,6 +463,14 @@ class AutoLoader {
 
 	);
 
+	/**
+	 * autoload - take a class name and attempt to load it
+	 * 
+	 * @param string $className Name of class we're looking for.
+	 * @return bool Returning false is important on failure as
+	 * it allows Zend to try and look in other registered autoloaders
+	 * as well. 
+	 */
 	static function autoload( $className ) {
 		global $wgAutoloadClasses;
 
@@ -484,7 +492,7 @@ class AutoLoader {
 			if ( !$filename ) {
 				# Give up
 				wfProfileOut( __METHOD__ );
-				return;
+				return false;
 			}
 		}
 
@@ -495,6 +503,7 @@ class AutoLoader {
 		}
 		require( $filename );
 		wfProfileOut( __METHOD__ );
+		return true;
 	}
 
 	static function loadAllExtensions() {