Ticket #16717: 16717.diff

wp-includes/query.php

@@ -2185 +2185 @@
                                 if ( !empty( $cat_query ) ) {
                                         $cat_query = reset( $cat_query );
                                         $the_cat = get_term_by( $cat_query['field'], $cat_query['terms'][0], 'category' );
-                                        if ( $the_cat ) {
+                                        if ( $the_cat && !is_wp_error( $the_cat ) ) {
                                                 $this->set( 'cat', $the_cat->term_id );
                                                 $this->set( 'category_name', $the_cat->slug );
                                         }