Can not add element to webform

hi. I use Drupal 10.2.3 , calendar_systems Version: 4.0.2 and webform 6.2.2 but get this error in webform add element

TypeError: function_exists(): Argument #1 ($function) must be of type string, array given in function_exists() (line 178 of /modules/contrib/calendar_systems/src/Element/CalendarSystemsDateTime.php).

Thanks, Amir
your solution works for me

Hi everyone,

I encountered the same error with Drupal 10.2.3, calendar_systems 4.0.2, and Webform 6.2.2:

TypeError: function_exists(): Argument #1 ($function) must be of type string, array given in function_exists() (line 178 of /modules/contrib/calendar_systems/src/Element/CalendarSystemsDateTime.php).

To fix this, I modified the code to check if the callback is a string before calling `function_exists()`. Here’s the relevant snippet I used:

if (is_string($callback) && function_exists($callback)) {
  $callback($element, $form_state, $date);
}

This prevents passing an array (or other non-string types) to function_exists(), which causes the TypeError.

I applied this check in both #date_date_callbacks and #date_time_callbacks loops. After this change, the error stopped occurring and the webform element addition works properly.

I believe this is a safer and cleaner fix than assuming the callback is an array or accessing $callback[1].