From 6333fe241c8e2181c6c537755d874eaa75eca4df Mon Sep 17 00:00:00 2001
From: Danny B <danny_b@users.mediawiki.org>
Date: Mon, 7 Dec 2009 18:28:25 +0000
Subject: [PATCH] * (bug 21776) Empty project + language interwikis do not work
 anymore [patch by Platonides]

---
 RELEASE-NOTES     | 1 +
 includes/Wiki.php | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/RELEASE-NOTES b/RELEASE-NOTES
index af9b47236f..402eff3741 100644
--- a/RELEASE-NOTES
+++ b/RELEASE-NOTES
@@ -669,6 +669,7 @@ Hopefully we will remove this configuration var soon)
 * (bug 21559) "logempty" message is now wrapped in a div with class
   "mw-warning-logempty" when used in log extract
 * (bug 20549) Parser tests were broken on SQLite backend
+* (bug 21776) Interwiki urls like http://en.wikibooks.org/wiki/cs: should give a redirect instead of a baderror.
 
 == API changes in 1.16 ==
 
diff --git a/includes/Wiki.php b/includes/Wiki.php
index faeb6e84a1..631cd03931 100644
--- a/includes/Wiki.php
+++ b/includes/Wiki.php
@@ -182,11 +182,13 @@ class MediaWiki {
 		global $wgContLang, $wgUser;
 		$action = $this->getVal( 'Action' );
 		$perferred = $wgContLang->getPreferredVariant( false );
-		// Invalid titles
-		if( is_null($title) || $title->getDBkey() == '' ) {
+
+		// Invalid titles. Bug 21776: The interwikis must redirect even if the page name is empty.
+		if( is_null($title) || ( ($title->getDBkey() == '') && ($title->getInterwiki() == '') ) ) {
 			$title = SpecialPage::getTitleFor( 'Badtitle' );
 			# Die now before we mess up $wgArticle and the skin stops working
 			throw new ErrorPageError( 'badtitle', 'badtitletext' );
+
 		// Interwiki redirects
 		} else if( $title->getInterwiki() != '' ) {
 			if( $rdfrom = $request->getVal( 'rdfrom' ) ) {
-- 
2.20.1