Data Model /Service Factory error generating manyToMany relationships

[yuning-zhang]

Bug report

Describe the bug

While generating manyToMany relationship between two models, retrieved relationship is not correct (using retrieve or list). This is possible due to ORM switching the select statement from different tables.

System information

Medusa version (including plugins): v2.0.8-preview
Node.js version: v20.12.2
Database: postgres (PostgreSQL) 14.12 (Homebrew)
Operating system: macOS 14.6
Browser (if relevant):

Steps to reproduce the behavior

Example repo of this bug https://github.com/yuning-zhang/medusa-bug

1. Set up this models

const Role = model.define("role", {
  id: model.id().primaryKey(),
  name: model.text().unique(),
  employees: model.manyToMany(() => Employee),
});

const Employee = model.define("employee", {
  id: model.id().primaryKey(),
  name: model.text().nullable(),
  first_name: model.text().nullable(),
  last_name: model.text().nullable(),
  email: model.text().unique(),
  roles: model.manyToMany(() => Role),
});

2. Generate migrations and run
3. Set up test route to generate example data

// src/api/company/test/route.ts

import { AuthenticatedMedusaRequest, MedusaResponse } from "@medusajs/medusa";
import B2BModuleService from "../../../modules/b2b/service";
import { B2B_MODULE } from "../../../modules/b2b";

type RequestBody = {};

export const POST = async (
  req: AuthenticatedMedusaRequest<RequestBody>,
  res: MedusaResponse
) => {
  const b2bModuleService: B2BModuleService = req.scope.resolve(B2B_MODULE);

  const role = await b2bModuleService.createRoles({
    name: "test_role",
  });

  const employee = await b2bModuleService.createEmployees({
    name: "Hello World",
    first_name: "Hello",
    last_name: "World",
    email: "test@test.com",
    roles: [role.id],
  });

  const fullEmployee = await b2bModuleService.retrieveEmployee(employee.id, {
    relations: ["roles"],
  });

  res.json({ role, employee, fullEmployee });
};

4. Send request to test route

curl -X POST 'http://localhost:9000/company/test' \
-H 'Content-Type: application/json' \
--data-raw '{}'

5. Received wrong response with roles not correct within employee. As you can see, role and employee are created correctly. But to retrieve the employee again with the roles relationship, the role id is actually the employee id, and the role name is the employee name

{
    -----------correct role created-------------
    "role": {
        "id": "01J7DA40JRN0FGDZABZZEPEA31",
        "name": "test_role",
        "employees": [],
        "created_at": "2024-09-10T06:32:16.216Z",
        "updated_at": "2024-09-10T06:32:16.216Z"
    },

    -----------correct employee created-------------
    "employee": {
        "id": "01J7DA40JZFENYDGKRTD056BZR",
        "name": "Hello World",
        "first_name": "Hello",
        "last_name": "World",
        "email": "test@test.com",
        "roles": [
            {
                "id": "01J7DA40JRN0FGDZABZZEPEA31"
            }
        ],
        "created_at": "2024-09-10T06:32:16.223Z",
        "updated_at": "2024-09-10T06:32:16.223Z"
    },

    -----------retrieve employee with id-------------
    "fullEmployee": {
        "id": "01J7DA40JZFENYDGKRTD056BZR",
        "name": "Hello World",
        "first_name": "Hello",
        "last_name": "World",
        "email": "test@test.com",
        "created_at": "2024-09-10T06:32:16.223Z",
        "updated_at": "2024-09-10T06:32:16.223Z",
        "deleted_at": null,
        "roles": [
            {
                -----------id here is same as employee id above?? and name?-------------
                "id": "01J7DA40JZFENYDGKRTD056BZR",
                "name": "Hello World",
                "created_at": "2024-09-10T06:32:16.223Z",
                "updated_at": "2024-09-10T06:32:16.223Z",
                "deleted_at": null
            }
        ]
    }
}

Expected behavior

The correct response in step 5 should be

{
    "fullEmployee": {
        "id": "01J7DA40JZFENYDGKRTD056BZR",
        "name": "Hello World",
        "first_name": "Hello",
        "last_name": "World",
        "email": "test@test.com",
        "created_at": "2024-09-10T06:32:16.223Z",
        "updated_at": "2024-09-10T06:32:16.223Z",
        "deleted_at": null,
        "roles": [
            {
                "id": "01J7DA40JRN0FGDZABZZEPEA31",
                "name": "test_role",
                "employees": [],
                "created_at": "2024-09-10T06:32:16.216Z",
                "updated_at": "2024-09-10T06:32:16.216Z"
            }
        ]
    }
}

Screenshots

If applicable, add screenshots to help explain your problem

Code snippets

Set up a public repo. Just need to run it locally with a database.

https://github.com/yuning-zhang/medusa-bug

Additional context

Not all manyToMany relationships are broken, not sure why this particular set up causes ORM to error.

[adrien2p]

Hey @yuning-zhang, just wanted to let you know that I am on it and ill get to the bottom of this issue

[adrien2p]

@yuning-zhang could you update your role DML with the following please (including mappedBy)

const Role = model.define("role", {
  id: model.id().primaryKey(),
  name: model.text().unique(),
  employees: model.manyToMany(() => Employee, {
    mappedBy: "roles",
  }),
});

it should fix this issue, in the meantime I ll find a way to warn when this happens

[yuning-zhang]

@adrien2p Thank you! That worked. I tested with adding mappedBy to Employee model too and it also fixed the issue. Do you recommend adding a mappedBy to one side of manyToMany relationship in general?

Feel free to close the ticket.

[adrien2p]

    mappedBy: "roles",

Yes at least one side must have the mapped by, I ve created a PR to throw if it is not the case (#9085)

@shahednasser maybe we should add that as part of the doc?