Ticket #22360: 22360.patch

wp-includes/link-template.php

@@ -1132 +1132 @@
         if ( $in_same_cat || ! empty( $excluded_categories ) ) {
                 $join = " INNER JOIN $wpdb->term_relationships AS tr ON p.ID = tr.object_id INNER JOIN $wpdb->term_taxonomy tt ON tr.term_taxonomy_id = tt.term_taxonomy_id";
 
-                if ( $in_same_cat ) {
+                if ( $in_same_cat && is_object_in_taxonomy( $post->post_type, 'category' ) ) {
                         $cat_array = wp_get_object_terms($post->ID, 'category', array('fields' => 'ids'));
-                        $join .= " AND tt.taxonomy = 'category' AND tt.term_id IN (" . implode(',', $cat_array) . ")";
+                        if ( $cat_array )
+                                $join .= " AND tt.taxonomy = 'category' AND tt.term_id IN (" . implode(',', $cat_array) . ")";
                 }
 
                 $posts_in_ex_cats_sql = "AND tt.taxonomy = 'category'";