Lumen application does not show stack trace in debug mode

Question

I have two Lumen microservices that (as far as I know) have the same configuration. One displays a user-friendly error page and the other does not.

Both services have this simple controller method:

public function test()
{
    echo $a;
    exit;
}

One of the services only shows:

Oops! An error occurred The server returns "500 Internal Server Error". Something is broken. Please let us know what you are doing when this error occurs. We will fix it as soon as possible. sorry cause any inconvenience.

Other services show stack traces, etc.

APP_DEBUG=true and APP_ENV=local on both environments. I verified these settings by echoing them in the controller method.

What setting might I be missing that prevents me from seeing the stack trace?

Answer 1

The problem is that I have a config/app.php file in which the debug setting is missing. Adding 'debug' => env('APP_DEBUG', false), to the array solved my problem.