next.js – GraphQL query returns an empty array on many-to-many relation – Prisma-Pothos

I’ve been struggling for some days now and feel dumb. I’m new to GraphQL and Prisma.

I’m creating a simple CRUD app with Next.js, GraphQL-Yoga, Prisma, Pothos, Apollo-Client and auth0. I use supabase for a PostgreSQL database. I want to query the posts and the corresponding user for each post. So I can map over it in react and display for example the role and the email of each user next to their post. I made a many-to-many relationship in the schema.prisma.

I tried using a one-to-many relation but I could only get, for example, the id, not the id and the email simultaneously.

GraphQL-Playground query:

query MyQuery {
  posts {
    title
    id
    user {
      email
      id
    }
  }
}

The user remains empty. Output:

{
  "data": {
    "posts": [
      {
        "title": "Lettuce",
        "id": "1",
        "user": []
      },
      {
        "title": "Banana",
        "id": "2",
        "user": []
      },
      {
        "title": "Carrot",
        "id": "3",
        "user": []
      }
    ]
  }
}

// /prisma/schema.prisma:
model User {
  id        String   @id @default(uuid())
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
  email     String?  @unique
  image     String?
  role      Role     @default(USER)
  Posts     Post[] 
}

model Post {
  id          String   @id @default(uuid())
  createdAt   DateTime @default(now())
  updatedAt   DateTime @updatedAt
  title       String
  description String
  category    String
  User        User[] 
}

// /graphQL/types/Post.ts
import { builder } from "../builder";

builder.prismaObject("Post", {
  fields: (t) => ({
    id: t.exposeID("id"),
    title: t.exposeString("title"),
    description: t.exposeString("description"),
    category: t.exposeString("category"),
    user: t.relation("User"),
  }),
});

builder.queryField("posts", (t) =>
  t.prismaField({
    type: ["Post"],
    resolve: (query, _parent, _args, _ctx, _info) =>
      prisma.post.findMany({
        ...query,
      }),
  })
);

It seems like this is what I need but when I integrate the <builder.queryType> portion I get an error saying:

PothosSchemaError: Duplicate typename: Another type with name Query already exists.

I tried some other things and got nothing. It seems like REST is so much easier.