return error as object from server actions

apps/login/next.config.mjs

@@ -33,9 +33,6 @@ const secureHeaders = [
 const nextConfig = {
   reactStrictMode: true, // Recommended for the `pages` directory, default in `app`.
   swcMinify: true,
-  experimental: {
-    serverComponentsErrorOverride: true,
-  },
   images: {
     remotePatterns: [
       {

apps/login/src/lib/server/loginname.ts

@@ -79,7 +79,7 @@ export async function sendLoginname(command: SendLoginnameCommand) {
     );
 
     if (!session.factors?.user?.id) {
-      throw Error("Could not create session for user");
+      return { error: "Could not create session for user" };
     }
 
     const methods = await listAuthenticationMethodTypes(
@@ -87,9 +87,10 @@ export async function sendLoginname(command: SendLoginnameCommand) {
     );
 
     if (!methods.authMethodTypes || !methods.authMethodTypes.length) {
-      throw Error(
+      return {
+        error:
           "User has no available authentication methods. Contact your administrator to setup authentication for the requested user.",
-      );
+      };
     }
 
     if (methods.authMethodTypes.length == 1) {
@@ -175,7 +176,7 @@ export async function sendLoginname(command: SendLoginnameCommand) {
     // TODO: do we need to handle login hints for IDPs here?
     await redirectUserToSingleIDPIfAvailable();
 
-    throw Error("Could not find user");
+    return { error: "Could not find user" };
   } else if (
     loginSettings?.allowRegister &&
     loginSettings?.allowUsernamePassword
@@ -232,5 +233,5 @@ export async function sendLoginname(command: SendLoginnameCommand) {
     return redirect("/password?" + new URLSearchParams(paramsPasswordDefault));
   }
 
-  throw Error("Could not find user");
+  return { error: "Could not find user" };
 }

apps/login/src/ui/UsernameForm.tsx

@@ -51,9 +51,13 @@ export default function UsernameForm({
       organization,
       authRequestId,
     }).catch((error: Error) => {
-      setError(error.message ?? "An internal error occurred");
+      setError("An internal error occurred");
     });
 
+    if (res?.error) {
+      setError(res.error);
+    }
+
     setLoading(false);
 
     return res;