不确定你在这里追求什么，可能还有其他选择，但有。this 挂钩：

/**
 * Filters a widget\'s settings before saving.
 *
 * Returning false will effectively short-circuit the widget\'s ability
 * to update settings.
 *
 * @since 2.8.0
 *
 * @param array     $instance     The current widget instance\'s settings.
 * @param array     $new_instance Array of new widget settings.
 * @param array     $old_instance Array of old widget settings.
 * @param WP_Widget $this         The current widget instance.
 */
 $instance = apply_filters( 
    \'widget_update_callback\', 
    $instance, 
    $new_instance, 
    $old_instance, 
    $this 
);

add_filter( \'widget_update_callback\', function( $instance, $new, $old, $obj )
{
    if( \'text\' === $obj->id_base && ! empty( $instance[\'text\'] ) )
    {
        // Warning this overrides the widget instance text input:
        // $instance[\'text\'] = \'override text\';
    }

    return $instance;
}, 10, 4 );