Ticket #11018: 11018_prevent_loop.diff

C:/xampp/htdocs/wordpress_trunk/wp-admin/includes/post.php

@@ -124 +124 @@
 }
 
 /**
+ * Sanity check the page to make sure the pending modification doesn't result in 
+ * an orphaned chain or form a loop. If so, don't try to change the post_parent
+ */
+function _sanity_check_page_chain( &$post_data ) {
+        global $wpdb; 
+        
+        if ( 'page' != $post_data[ 'post_type' ] )
+                return; 
+        
+        if ( empty( $post_data[ 'post_parent' ] ) ) //skip '' or 0
+                return; 
+        
+        $p = (int)( $post_data[ 'post_parent' ] ); 
+        
+        if ( $p == $post_data[ 'post_ID' ] ){ //fix self loop
+                $post_data[ 'post_parent' ] = 0; 
+                return; 
+        }
+        
+        $post_parent_db = $wpdb->get_var( $wpdb->prepare("SELECT post_parent FROM $wpdb->posts WHERE ID = %d LIMIT 1", $post_data[ 'post_ID' ] ) ); 
+        if ( is_null( $post_parent_db ) || $post_parent_db == $p )  //same value
+                return; 
+
+        //try to set post_parent to a new value, make sure it does not form a loop, or being part of orphaned chain
+        $track_parents[] = (int)$post_data[ 'post_ID' ];
+        
+        while ( $p > 0 ){
+                
+                $track_parents[] = $p; 
+                
+                $p = $wpdb->get_var( $wpdb->prepare("SELECT post_parent FROM $wpdb->posts WHERE ID = %d LIMIT 1", $p ) ); 
+                
+                if ( is_null( $p ) ){ //encountered an orphan page in the chain
+                        $post_data[ 'post_parent' ] = $post_parent_db; 
+                        return; 
+                } 
+                
+                //encountered a loop, restore the post_parent value from db
+                if ( in_array( $p, $track_parents ) ) { 
+                        $post_data[ 'post_parent' ] = $post_parent_db; 
+                        return; 
+                }
+        }
+}
+
+/**
  * Update an existing post with values provided in $_POST.
  *
  * @since unknown
@@ -189 +235 @@
 
         add_meta( $post_ID );
 
+        _sanity_check_page_chain( $post_data ); 
+
         wp_update_post( $post_data );
 
         // Reunite any orphaned attachments with their parent