If Next.js version is 15 or higher, does it only return null when trying to obtain a session?

[fumiyasac]

Introduction

I'm currently trying to create a sample app for an EC site.

• NextJS E-Com Masterclass: Learn The All New Next JS）

So, I wrote code to redirect if a session exists, but the session remains null forever and it doesn't work properly even though I use getServerSession.

I am in deep trouble and cannot move on as things stand, so I am desperately asking for help.

Will this library not work properly if Next.js version is 15 or higher?

※ I use Next.js 15.1.3.

auth.ts

// [NOTE] next-auth version "0.0.0-pr.11562.ed0fce23"

import NextAuth, { NextAuthOptions } from "next-auth";
import CredentialsProvider from "next-auth/providers/credentials";
import { SignInCredentials } from "./app/types";

const authConfig: NextAuthOptions = {
  providers: [CredentialsProvider({
    type: 'credentials',
    credentials: {},
    async authorize(credentials, request) {

      const { email, password } = credentials as SignInCredentials;
      const { user, error } = await fetch('http://localhost:3000/api/users/signin', {
        method: 'POST',
        body: JSON.stringify({ email, password }),
      }).then(async res => await res.json());

      if (error) return null;
      return { id: user.id, ...user };
    },
  })],
  callbacks: {
    async jwt(params) {
      console.log('jwt ===> ', params);
      if (params.user) {
        params.token.user = params.user
      }
      return params.token;
    },
    async session(params) {
      console.log('session ===> ', params);
      const user = params.token.user;
      if (user) {
        params.session.user = { ...params.session.user, ...user };
      }
      return params.session;
    },
  },
};

const handler = NextAuth(authConfig);
export { handler as GET, handler as POST, authConfig };
export const { handlers, auth, signIn, signOut } = NextAuth(authConfig);

app/api/auth/[...nextauth]/route.ts

export { GET, POST } from "@/auth";

app/(guest_routes)/layout.tsx

import { getServerSession } from "next-auth/next";
import { authConfig } from '@/auth';
import React, { ReactNode } from 'react';
import { redirect } from "next/navigation";
interface Props {
    children: ReactNode;
};

// This code is not working for me...
export default async function GuestLayout({ children }: Props) {

  const session = await getServerSession(authConfig);
  console.log(session); // 👉 null (This is too strange!!!!!!)
  console.log(!session); // 👉 true (I'd like to change false!!!!!!)

  if (session) {
    return redirect("/");
  }

  return (
    <div>{children}</div>
  );
};

Thanks 🙏

[fumiyasac]

When I try to update, I get an error like this.