Problem with auth.ts session callback

[pierol234]

Hi, I have a problem with my auth.ts file.
I try to npm run build my project but i can't solve this error:

   ▲ Next.js 15.0.3
   - Environments: .env

   Creating an optimized production build ...
 ✓ Compiled successfully
   Linting and checking validity of types  ..Failed to compile.

./auth.ts:32:15
Type error: Type '({ token }: { session: { user: AdapterUser; } & AdapterSession; user: AdapterUser; } & { session: Session; token: JWT; } & { newSession: any; trigger?: "update" | undefined; }) => Promise<...>' is not assignable to type '(params: { session: { user: AdapterUser; } & AdapterSession; user: AdapterUser; } & { session: Session; token: JWT; } & { newSession: any; trigger?: "update" | undefined; }) => Awaitable<...>'.
  Type 'Promise<void>' is not assignable to type 'Awaitable<Session | DefaultSession>'.
    Type 'Promise<void>' is not assignable to type 'PromiseLike<Session | DefaultSession>'.
      Types of property 'then' are incompatible.
        Type '<TResult1 = void, TResult2 = never>(onfulfilled?: ((value: void) => TResult1 | PromiseLike<TResult1>) | null | undefined, onrejected?: ((reason: any) => TResult2 | PromiseLike<...>) | null | undefined) => Promise<...>' is not assignable to type '<TResult1 = Session | DefaultSession, TResult2 = never>(onfulfilled?: ((value: Session | DefaultSession) => TResult1 | PromiseLike<TResult1>) | null | undefined, onrejected?: ((reason: any) => TResult2 | PromiseLike<...>) | ... 1 more ... | undefined) => PromiseLike<...>'.
          Types of parameters 'onfulfilled' and 'onfulfilled' are incompatible.
            Types of parameters 'value' and 'value' are incompatible.
              Type 'void' is not assignable to type 'Session | DefaultSession'.

I can't solve this error and I try to find some solution but no fix is working for me.

This is my auth.ts file and my next-auth.d.ts

Auth.ts

import NextAuth from "next-auth"
import { PrismaAdapter } from "@auth/prisma-adapter"
import { db } from "@/lib/db"
import authConfig from "./auth.config"
import { getUserByEmail, getUserById, updateLastAccess  } from "@/data/user"

export const { 
    handlers, 
    auth, 
    signIn, 
    signOut,
} = NextAuth({
    callbacks: {
        async signIn( { user }) {
            console.log(user?.id);
            const existingUser = await getUserById(user.id ?? "");
            if(!existingUser?.emailVerified) {
                return false;
            }
            await updateLastAccess(String(existingUser?.ID));
            return true;
        
        },
        async jwt( {token}) {
            if(!token.sub) return token;
            const existingUser = await getUserByEmail(token.email ?? "");
            token.role = existingUser?.Ruolo;
            return token;
        },
        async session({ session, token}) {
            if(token.sub && session.user) {
                session.user.id = token.sub;
            }
            if(token.role && session.user) {
                session.user.role = token.role as UserRole;
            }
        },
    },  
    adapter: PrismaAdapter(db),
    session: {strategy: "jwt"},
    ...authConfig,

})

next-auth.d.ts
import { UserRole } from "@prisma/client";
import NextAuth, { type DefaultSession} from "next-auth";
declare module "next-auth" {
    interface Session {
        user: {
            id: string
            role: UserRole;
        } & DefaultSession['user'];
    }
}

My UserRole:

enum UserRole {
  ADMIN
  USER
}

auth.config.ts

import { NextAuthConfig } from "next-auth"
import CredentialsProvider from "next-auth/providers/credentials";
import { LoginSchema } from "./schemas"
import bcrypt from "bcryptjs"
import { getUserByEmail } from "@/data/user";
export default {

  providers: [
    CredentialsProvider({
    async authorize(credentials) {
        const validateFields = LoginSchema.safeParse(credentials);
        if(validateFields.success) {
            const { email, password } = validateFields.data;
            const user = await getUserByEmail(email);
            if(!user || !user.password) return null;
            const passwordMatch = await bcrypt.compare(password, user.password);
            if(passwordMatch) return user;
        }
        return null;
    }
  })],
} satisfies NextAuthConfig