1 files changed, 60 insertions, 21 deletions

diff --git a/includes/specials/SpecialDoubleRedirects.php b/includes/specials/SpecialDoubleRedirects.php
index 5864ca9f..5a5d749c 100644
--- a/includes/specials/SpecialDoubleRedirects.php
+++ b/includes/specials/SpecialDoubleRedirects.php
@@ -33,9 +33,17 @@ class DoubleRedirectsPage extends QueryPage {
 		parent::__construct( $name );
 	}
 
-	function isExpensive() { return true; }
-	function isSyndicated() { return false; }
-	function sortDescending() { return false; }
+	function isExpensive() {
+		return true;
+	}
+
+	function isSyndicated() {
+		return false;
+	}
+
+	function sortDescending() {
+		return false;
+	}
 
 	function getPageHeader() {
 		return $this->msg( 'doubleredirectstext' )->parseAsBlock();
@@ -43,23 +51,45 @@ class DoubleRedirectsPage extends QueryPage {
 
 	function reallyGetQueryInfo( $namespace = null, $title = null ) {
 		$limitToTitle = !( $namespace === null && $title === null );
+		$dbr = wfGetDB( DB_SLAVE );
 		$retval = array (
-			'tables' => array ( 'ra' => 'redirect',
-					'rb' => 'redirect', 'pa' => 'page',
-					'pb' => 'page', 'pc' => 'page' ),
-			'fields' => array ( 'namespace' => 'pa.page_namespace',
-					'title' => 'pa.page_title',
-					'value' => 'pa.page_title',
-					'nsb' => 'pb.page_namespace',
-					'tb' => 'pb.page_title',
-					'nsc' => 'pc.page_namespace',
-					'tc' => 'pc.page_title' ),
-			'conds' => array ( 'ra.rd_from = pa.page_id',
-					'pb.page_namespace = ra.rd_namespace',
-					'pb.page_title = ra.rd_title',
-					'rb.rd_from = pb.page_id',
-					'pc.page_namespace = rb.rd_namespace',
-					'pc.page_title = rb.rd_title' )
+			'tables' => array (
+				'ra' => 'redirect',
+				'rb' => 'redirect',
+				'pa' => 'page',
+				'pb' => 'page'
+			),
+			'fields' => array(
+				'namespace' => 'pa.page_namespace',
+				'title' => 'pa.page_title',
+				'value' => 'pa.page_title',
+
+				'nsb' => 'pb.page_namespace',
+				'tb' => 'pb.page_title',
+
+				// Select fields from redirect instead of page. Because there may
+				// not actually be a page table row for this target (e.g. for interwiki redirects)
+				'nsc' => 'rb.rd_namespace',
+				'tc' => 'rb.rd_title',
+				'iwc' => 'rb.rd_interwiki',
+			),
+			'conds' => array(
+				'ra.rd_from = pa.page_id',
+
+				// Filter out redirects where the target goes interwiki (bug 40353).
+				// This isn't an optimization, it is required for correct results,
+				// otherwise a non-double redirect like Bar -> w:Foo will show up
+				// like "Bar -> Foo -> w:Foo".
+
+				// Need to check both NULL and "" for some reason,
+				// apparently either can be stored for non-iw entries.
+				'ra.rd_interwiki IS NULL OR ra.rd_interwiki = ' . $dbr->addQuotes( '' ),
+
+				'pb.page_namespace = ra.rd_namespace',
+				'pb.page_title = ra.rd_title',
+
+				'rb.rd_from = pb.page_id',
+			)
 		);
 		if ( $limitToTitle ) {
 			$retval['conds']['pa.page_namespace'] = $namespace;
@@ -79,11 +109,16 @@ class DoubleRedirectsPage extends QueryPage {
 	function formatResult( $skin, $result ) {
 		$titleA = Title::makeTitle( $result->namespace, $result->title );
 
+		// If only titleA is in the query, it means this came from
+		// querycache (which only saves 3 columns).
+		// That does save the bulk of the query cost, but now we need to
+		// get a little more detail about each individual entry quickly
+		// using the filter of reallyGetQueryInfo.
 		if ( $result && !isset( $result->nsb ) ) {
 			$dbr = wfGetDB( DB_SLAVE );
 			$qi = $this->reallyGetQueryInfo( $result->namespace,
 					$result->title );
-			$res = $dbr->select($qi['tables'], $qi['fields'],
+			$res = $dbr->select( $qi['tables'], $qi['fields'],
 					$qi['conds'], __METHOD__ );
 			if ( $res ) {
 				$result = $dbr->fetchObject( $res );
@@ -94,7 +129,7 @@ class DoubleRedirectsPage extends QueryPage {
 		}
 
 		$titleB = Title::makeTitle( $result->nsb, $result->tb );
-		$titleC = Title::makeTitle( $result->nsc, $result->tc );
+		$titleC = Title::makeTitle( $result->nsc, $result->tc, '', $result->iwc );
 
 		$linkA = Linker::linkKnown(
 			$titleA,
@@ -127,4 +162,8 @@ class DoubleRedirectsPage extends QueryPage {
 
 		return( "{$linkA} {$edit} {$arr} {$linkB} {$arr} {$linkC}" );
 	}
+
+	protected function getGroupName() {
+		return 'maintenance';
+	}
 }