Error: [] operator not supported for strings in claro_preprocess_admin_block_content()

Hello ashutosh.mishra,
I install claro theme but I have not got any error. Shared screenshot as well .
my configuration:
drupal-10.1.3
php 8.1.2

Not able to reproduce the issue!

We've encountered the same issue on the following page: /en/admin/
This happens on all environments including production.
Drupal version we use is 9.5.10.

I've attached a patch that works for us, it simply negates the issue, but does not address it's root.
ashutosh.mishra please test this patch

Thanks

The attributes options should be an array https://git.drupalcode.org/project/drupal/-/blob/11.x/core/lib/Drupal/Co...

   *   - 'attributes': An associative array of HTML attributes that will be
   *     added to the anchor tag if you use the \Drupal\Core\Link class to make
   *     the link.

So if the getOption returns a string, then the definition of the item is not correct.

 $item['url']->getOption('attributes') ?: [];

In our case, it is because of a view menu tab.

MariaDB [drupal]> select route_name, url, menu_name, parent, provider from menu_tree where options like '%class";s:0%';
+---------------------------+-----+-----------+--------------------+-------------------+
| route_name                | url | menu_name | parent             | provider          |
+---------------------------+-----+-----------+--------------------+-------------------+
| view.reporter_news.page_1 |     | admin     | mysite.admin | menu_link_content |
+---------------------------+-----+-----------+--------------------+-------------------+
1 row in set (0.001 sec)

Column options unserialized:

array (
  'attributes' => 
  array (
    'title' => '',
    'id' => '',
    'name' => '',
    'rel' => '',
    'class' => '',
    'style' => '',
    'target' => '',
    'accesskey' => '',
  ),
  'item_attributes' => 
  array (
    'id' => '',
    'class' => '',
    'style' => '',
  ),
  'query' => 
  array (
  ),
)

We are not sure, why views are saving the class as a string instead of an array.

After some research seems like like is a custom menu item, and the attributes comes from menu_link_attributes