FU r97022: Fallback to empty array for getExtraSortFields() result in __construct...

diff --git a/includes/Pager.php b/includes/Pager.php
index 993a7ab..6178b9a 100644 (file)
--- a/includes/Pager.php
+++ b/includes/Pager.php
@@ -119,18 +119,22 @@ abstract class IndexPager implements Pager {
                $this->mIsBackwards = ( $this->mRequest->getVal( 'dir' ) == 'prev' );
                $this->mDb = wfGetDB( DB_SLAVE );
 
-               $index = $this->getIndexField();
-               $extraSort = $this->getExtraSortFields();
+               $index = $this->getIndexField(); // column to sort on
+               $extraSort = $this->getExtraSortFields(); // extra columns to sort on for query planning
                $order = $this->mRequest->getVal( 'order' );
                if( is_array( $index ) && isset( $index[$order] ) ) {
                        $this->mOrderType = $order;
                        $this->mIndexField = $index[$order];
-                       $this->mExtraSortFields = (array)$extraSort[$order];
+                       $this->mExtraSortFields = isset( $extraSort[$order] )
+                               ? (array)$extraSort[$order]
+                               : array();
                } elseif( is_array( $index ) ) {
                        # First element is the default
                        reset( $index );
                        list( $this->mOrderType, $this->mIndexField ) = each( $index );
-                       $this->mExtraSortFields = (array)$extraSort[$this->mOrderType];
+                       $this->mExtraSortFields = isset( $extraSort[$this->mOrderType] )
+                               ? (array)$extraSort[$this->mOrderType]
+                               : array();
                } else {
                        # $index is not an array
                        $this->mOrderType = null;
@@ -599,8 +603,8 @@ abstract class IndexPager implements Pager {
         * not be used in the pager offset or in any links for users.
         *
         * If getIndexField() returns an array of 'querykey' => 'indexfield' pairs then
-        * this must return a corresponding array of 'querykey' => array( fields...) pairs,
-        * so that a request with &count=querykey will use array( fields...) to sort.
+        * this must return a corresponding array of 'querykey' => array( fields...) pairs
+        * in order for a request with &count=querykey to use array( fields...) to sort.
         *
         * This is useful for pagers that GROUP BY a unique column (say page_id)
         * and ORDER BY another (say page_len). Using GROUP BY and ORDER BY both on