preg_match(): Compilation failed in Shield and Myth/Auth

It seems your route is invalid.
Check your routes.

php spark routes

Thank you very much.

I'm still learning about CodeIgniter.
>php spark routes

There was no problem before using Shield or Myth/Auth,
but the problem occurred when using the locale as follows.

App/Configuration/Routes.php
/*=================================*/
$routes->group('{locale}', static function ($routes) {
      service('auth')->routes($routes);
});
/*=================================*/

Of course there is no problem with the routing above.
This problem was caused by my incorrect use of regular expressions in other route rules.

---

@dolsorina Are you trying to access routes {locale}/login as below?

eg:

http://localhost:8080/index.php/fa/auth/a/show
http://localhost:8080/index.php/ja/auth/a/show

If yes, you should know that currently Shield does not support this method.

I want to know if you really need this possibility or not.

Because in order to support this method, we have to make changes in the file  Auth class LoginController and ... Shield.

Thank you very much for your interest and reply.

The problem was caused by using regular expressions that violate routing rules.