When missing AUTH_URL, should error be being thrown or warning printed?

[vanviethieuanh]

Goals

When missing AUTH_URL (or NEXTAUTH_URL) I expected an error to be thrown or a warning printed.

Non-Goals

No response

Background

I'm using Svelte Kit now and when I set up Authjs like this without config AUTH_URL nor NEXTAUTH_URL at all:

SvelteKitAuth({
	adapter: MongoDBAdapter(mongoClient, {
		databaseName: 'auth',
		collections: {
			Accounts: 'accounts',
			Sessions: 'sessions',
			Users: 'users',
			VerificationTokens: 'verificationTokens'
		}
	}),
	providers: [Google({ clientId: AUTH_GG_CLIENT_ID, clientSecret: AUTH_GG_CLIENT_SECRET })],
	session: {
		generateSessionToken: () => createId(),
		strategy: 'database'
	},
	...
});

everything works fine when I run it with yarn run dev. However, when I run yarn run build && yarn run preview an error happened (I consider it an error but it is not logging nor throwing any error so if it is not then it is not 🥲).

When I ran the built version, I logged in successfully, the token is sitting in my cookies (which is good). However, this code on the client side (a +page.svelte file) returns the user as undefined:

import { page } from '$app/stores';
const user = $page.data.session?.user;

this also happened on server-side files, for example, session on this +page.server.js file is null:

export async function load({ params, url, locals, cookies }) {
	const session = await locals.auth(); // session is null
}

The problem here is my users were logged in successfully. If something is missing, an error should be thrown, so I can tell my users we have a problem. Or at least somehow, I would know why the token is in my cookies but my session is null. However, no error was thrown nor warning was printed.

Proposal

I suggest we throw an error similar to MissingSecret or at least print a warning when the session token is received but something is wrong and cannot get the session.

A supper thank you to all of you who contributed to this repository!