InvalidArgumentException: Class "toolbar_menu_navigation_links" does not exist.

We don't want to add an explicit dependency. Also toolbar will soon be replaced by the new navigation module.

Unfortunately I'll have to close this as won't fix.

I think we have different opinions about stable code.

I don't think we have different opinions about stable code – but there is quite some complexity maintaining the main admin theme which has a ton of hidden requirements for different use cases which might not be obvious at the first glance.

I got this issue just now by installing latest gin theme without toolbar module enabled what caused me couldn't access any admin page.

I had to use below code snippet to change the admin theme so that I can access the admin pages again.

$config = \Drupal::service('config.factory')->getEditable('system.theme');
$config->set('admin', 'YOUR_THEME')->save();

Even if I install toolbar,I still couldn't get the gin 4.0.2 working.
it seems that it also has conflicts with the module Ui Icons:~

2025/01/25 01:05:51 [error] 14876#17080: *377 FastCGI sent in stderr: "Uncaught PHP Exception Error: "Call to a member function getOption() on string" at H:\wemp\nginx\html\nkmz\modules\contrib\ui_icons\modules\ui_icons_menu\ui_icons_menu.module line 95" while reading response header from upstream, client: 127.0.0.1, server: localhost, request: "GET /admin/appearance HTTP/1.1", upstream: "fastcgi://127.0.0.1:9000", host: "127.0.0.1:81", referrer: "http://127.0.0.1:81/admin/appearance"