Changeset 30239

Timestamp:

11/05/2014 01:08:44 AM (10 years ago)

Author:

boonebgorges

Message:

Enforce ORDER BY and LIMIT clauses in term_exists() queries.

In case of edge cases where a duplicate term might exist in a replicated
database for a split second, these explicit query clauses ensure that
term_exists() will always recognize the oldest matched term as the
canonical one. See [30238] for background.

Props pento.
See #22023, #5809.

File:

• trunk/src/wp-includes/taxonomy.php (modified) (2 diffs)

trunk/src/wp-includes/taxonomy.php

@@ -2055 +2055 @@
     $where_fields = array($slug);
     $else_where_fields = array($term);
+    $orderby = 'ORDER BY t.term_id ASC';
+    $limit = 'LIMIT 1';
     if ( !empty($taxonomy) ) {
         if ( is_numeric( $parent ) ) {
@@ -2067 +2069 @@
         $else_where_fields[] = $taxonomy;
 
-        if ( $result = $wpdb->get_row( $wpdb->prepare("SELECT tt.term_id, tt.term_taxonomy_id FROM $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy as tt ON tt.term_id = t.term_id WHERE $where AND tt.taxonomy = %s", $where_fields), ARRAY_A) )
+        if ( $result = $wpdb->get_row( $wpdb->prepare("SELECT tt.term_id, tt.term_taxonomy_id FROM $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy as tt ON tt.term_id = t.term_id WHERE $where AND tt.taxonomy = %s $orderby $limit", $where_fields), ARRAY_A) )
             return $result;
 
-        return $wpdb->get_row( $wpdb->prepare("SELECT tt.term_id, tt.term_taxonomy_id FROM $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy as tt ON tt.term_id = t.term_id WHERE $else_where AND tt.taxonomy = %s", $else_where_fields), ARRAY_A);
-    }
-
-    if ( $result = $wpdb->get_var( $wpdb->prepare("SELECT term_id FROM $wpdb->terms as t WHERE $where", $where_fields) ) )
+        return $wpdb->get_row( $wpdb->prepare("SELECT tt.term_id, tt.term_taxonomy_id FROM $wpdb->terms AS t INNER JOIN $wpdb->term_taxonomy as tt ON tt.term_id = t.term_id WHERE $else_where AND tt.taxonomy = %s $orderby $limit", $else_where_fields), ARRAY_A);
+    }
+
+    if ( $result = $wpdb->get_var( $wpdb->prepare("SELECT term_id FROM $wpdb->terms as t WHERE $where $orderby $limit", $where_fields) ) )
         return $result;
 
-    return $wpdb->get_var( $wpdb->prepare("SELECT term_id FROM $wpdb->terms as t WHERE $else_where", $else_where_fields) );
+    return $wpdb->get_var( $wpdb->prepare("SELECT term_id FROM $wpdb->terms as t WHERE $else_where $orderby $limit", $else_where_fields) );
 }