Ticket #42860: 42860-1.2.patch

src/wp-includes/class-wp-query.php

@@ -3158 +3158 @@
                          */
                         $this->found_posts = $wpdb->get_var( apply_filters_ref_array( 'found_posts_query', array( 'SELECT FOUND_ROWS()', &$this ) ) );
                 } else {
-                        $this->found_posts = count( $this->posts );
+                        $this->found_posts = is_array( $this->posts ) ? count( $this->posts ) : 0;
                 }
 
                 /**