Function in admin_cols throws PHP error on custom post type list

[herrschuessler]

I have a taxonomy assigned to a custom post type with a custom admin_cols function, like this:

register_extended_taxonomy(
  'tax_x',
  [ 'cpt_x' ],
  [
    'public'       => true,
    'hierarchical' => true,
    'admin_cols'   => [
      'my_column' => [
        'title'    => 'My Function',
        'function' => function( $term_id ) {
          // Do something ...
        },
      ],
    ],

  ],
);

The custom column shows up on the taxonomy listing in the admin area, but when I open the post type listing for the corresponding post typ, I get the PHP error (via Query Monitor): Uncaught Exception: Serialization of 'Closure' is not allowed – wp-includes/class-wp-object-cache.php:465, and when editing a custom post, the taxonomy meta box is not showing in the block editor.

The error disapears after removing the my_column part from above.

[herrschuessler]

Edit: The meta box not showing was due to missing the meta_box key in the arguments, sorry.

[johnbillion]

Can you get a full stack trace for that error please? This should be available from your PHP error log file, or by installing Xdebug.

Cheers!

[herrschuessler]

Sorry, should have done that in the first place. Looking at the stack trace, it looks like the problem is related to Debug Bar.

[07-Jun-2021 08:13:19 UTC] PHP Fatal error:  Uncaught Exception: Serialization of 'Closure' is not allowed in /wp-includes/class-wp-object-cache.php:465
Stack trace:
#0 /wp-includes/class-wp-object-cache.php(465): serialize(Array)
#1 /wp-content/plugins/debug-bar/panels/class-debug-bar-object-cache.php(18): WP_Object_Cache->stats()
#2 /wp-content/plugins/debug-bar/debug-bar.php(370): Debug_Bar_Object_Cache->render()
#3 /wp-includes/class-wp-hook.php(292): Debug_Bar->render('')
#4 /wp-includes/class-wp-hook.php(316): WP_Hook->apply_filters(NULL, Array)
#5 /wp-includes/plugin.php(484): WP_Hook->do_action(Array)
#6 /wp-admin/admin-footer.php(78): do_action('admin_footer', '')
#7 /wp-admin/edit.php(489): require_once('/www/htdocs/...')
#8 {main}
  thrown in /wp-includes/class-wp-object-cache.php on line 465

After disabling that plugin, the error goes away. Sorry again for not checking that.

[johnbillion]

I've done some testing and I'm unable to reproduce this problem, but judging by the stack trace I'd say this is a problem in Debug Bar where it's trying to serialize a closure.

[redactuk]

@herrschuessler A long time ago, but just wondered if you found solution to this? as I'm getting the same.