🥅 Display OIDC error properly (#261)

src/routes/+layout.svelte

@@ -136,7 +136,7 @@
 	{#if isSettingsOpen}
 		<SettingsModal on:close={() => (isSettingsOpen = false)} settings={data.settings} />
 	{/if}
-	{#if data.requiresLogin ? !data.user : !data.settings.ethicsModalAcceptedAt}
+	{#if !$page.error && (data.requiresLogin ? !data.user : !data.settings.ethicsModalAcceptedAt)}
 		<LoginModal settings={data.settings} />
 	{/if}
 	<slot />

src/routes/login/callback/{+server.ts → +page.server.ts}

@@ -4,16 +4,16 @@ import { z } from "zod";
 import { base } from "$app/paths";
 import { updateUser } from "./updateUser";
 
-export async function GET({ url, locals, cookies }) {
-	const { error: errorName } = z
+export async function load({ url, locals, cookies }) {
+	const { error: errorName, error_description: errorDescription } = z
 		.object({
 			error: z.string().optional(),
+			error_description: z.string().optional(),
 		})
 		.parse(Object.fromEntries(url.searchParams.entries()));
 
 	if (errorName) {
-		// TODO: Display denied error on the UI
-		throw redirect(302, `${base}/`);
+		throw error(400, errorName + (errorDescription ? ": " + errorDescription : ""));
 	}
 
 	const { code, state } = z