Prisma extension not working inside generated RelationResolver

[p0thi]

Hi everyone,

I'm encountering an issue where my extended Prisma client (prisma.$extends()) doesn't add the __typename field to the root element inside the generated relation resolvers.

This is my extenstion

It adds the __typename field to each object coming from prisma. This field contains the name of its Model

const brandExtension = Prisma.defineExtension((client) => {
type ModelKey = Exclude<keyof typeof client, `$${string}` | symbol>;
type Result = {
  [K in ModelKey]: {
    __typename: {
      needs: Record<string, never>;
      compute: () => Capitalize<K>;
    };
  };
};

const result = {} as Result;
const modelKeys = Object.keys(client).filter(
  (key) => !key.startsWith("$") && !key.startsWith("_"),
) as ModelKey[];
modelKeys.forEach((k) => {
  const capK = k.charAt(0).toUpperCase() + k.slice(1);
  result[k] = {
    __typename: {
      needs: {},
      // eslint-disable-next-line @typescript-eslint/no-explicit-any
      compute: () => capK as any,
    },
  };
});

return client.$extends({ result });
});

export const prisma = new PrismaClient().$extends(brandExtension);

Here's a detailed breakdown:

• Extended Prisma Client: I am using an extended prisma client, that adds the model name to a new __typename field of each object coming from prisma.
• Custom Auth Hook: I use a custom auth hook named MFAuth to add authorization checks to certain fields using ModelsEnhanceMap:

const userEnhanceConfig: ModelConfig<"User"> = {
   fields: {
    email: [MFAuth(["read", "User", "email"])],
    // ...
   },
};
const modelsEnhanceMap: ModelsEnhanceMap = {
  User: userEnhanceConfig,
  // ...
};
applyModelsEnhanceMap(modelsEnhanceMap);

• I am using the Auth Checker to check the root object to verify if the user is authorized to request certain fields of it.
• Prisma context: I made sure i only use the extended prisma client everywhere and also put it in the context.

For my own resolvers and the generated CrudResolvers, this setup works perfectly, and I can detect the model of each object by its __typename field inside the auth checker.

Example that works:

query User {
  user {
    email
  }
}

However, when using the generated RelationResolvers, the root object of the nested objects does not include the __typename field.

Example that doesn't work:

query Post {
  post {
    title
    user {
      email
    }
  }
}

In this case, the user object from the PostRelationResolver doesn't contain the __typename field in the root object.

How can I ensure the __typename field is included in the root object for auto-generated relation resolvers?

Thank you for your assistance!