Steps to reproduce:

1. Adding error(_s('widget.view.php logging')); in modules/lesson_gauge_chart/views/widget.view.php file as follows.
2. <?php
          
          /**
           * Gauge chart widget view.
           *
           * @var CView $this
           * @var array $data
           */
          
          error(_s('widget.view.php logging'));
          // error_log(print_r($data['value']['value'], true));
          (new CWidgetView($data))
              ->addItem([
                  new CTag('h1', true, $data['description']),
                  new CDiv($data['value'] !== null ? $data['value']['value'] : _('No data'))
              ])
              ->show();

Result:
"widget.view.php logging" message is shown on web browser.

Expected:
"widget.view.php logging" message is saved to log file