MongoDB: Many to many relation issue

Bug description

see schema below

when I try to create a new record using the following code:

const doc = await this.prisma.book.create({
			data: {
				price,
				title,
				category: {
					connect: { id: categoryID[0] },
				},
				authorID: undefined,
				author: { connect: { id: authorID } },
			},
		});

How to reproduce

1. Create a prisma schema using the provided schema and use mongo db
2. Try to add categories to book and author at the same time
3. See typescript error when you try to add authorId and category at the same time, when using the connect options, record inserts but get panic from prisma engine.
4. Cannot query books anymore after a failed insertion

Expected behavior

It should create a collection to store the relation which is not getting created and gets an error instead

PANIC in query-engine\connectors\mongodb-query-connector\src\root_queries\write.rs:219:74
called `Option::unwrap()` on a `None` value

Prisma information

model Author {
    id        String @id @default(dbgenerated()) @map("_id") @db.ObjectId
    firstName String
    lastName  String
    Book      Book[]
}

model Category {
    id    String @id @default(dbgenerated()) @map("_id") @db.ObjectId
    title String
    slug  String @unique
    books Book[]
}

model Book {
    id       String     @id @default(dbgenerated()) @map("_id") @db.ObjectId
    title    String
    author   Author     @relation(fields: [authorID], references: [id])
    category Category[]
    price    Int
    authorID String     @db.ObjectId
}

Environment & setup

• OS Windows 10
• Mongodb 4.4 local install
• Nodejs 14 lts
• prisma version 2.22.1(mongodb early access)

Prisma Version

prisma               : 2.22.1
@prisma/client       : 2.22.1
Current platform     : windows
Query Engine         : query-engine 60cc71d884972ab4e897f0277c4b84383dddaf6c (at node_modules\@prisma\engines\query-engine-windows.exe)
Migration Engine     : migration-engine-cli 60cc71d884972ab4e897f0277c4b84383dddaf6c (at node_modules\@prisma\engines\migration-engine-windows.exe)
Introspection Engine : introspection-core 60cc71d884972ab4e897f0277c4b84383dddaf6c (at node_modules\@prisma\engines\introspection-engine-windows.exe)
Format Binary        : prisma-fmt 60cc71d884972ab4e897f0277c4b84383dddaf6c (at node_modules\@prisma\engines\prisma-fmt-windows.exe)
Default Engines Hash : 60cc71d884972ab4e897f0277c4b84383dddaf6c
Studio               : 0.379.0
Preview Features     : mongoDb

[matthewmueller]

@crazydev901 this is a duplicate of: https://github.com/prisma/prisma/issues/6717 where we don’t auto-fix the relations yet.

The workaround now is to manually fill in the relation. Something like:

model User {
  id             String   @id @default(dbgenerated()) @map("_id") @db.ObjectId
  createdAt      DateTime @default(now())
  updatedAt      DateTime @updatedAt
  ...
  favProjects    Project[]  @relation(fields: [favProjectsIds])// Worker's favorite projects
  favProjectsIds String[] @db.Array(ObjectId)
  ...
}

model Project {
  id                String     @id @default(dbgenerated()) @map("_id") @db.ObjectId
  createdAt         DateTime   @default(now())
  updatedAt         DateTime   @updatedAt
  ...
+  userIds String[] @db.Array(ObjectId)
+  users   User[]   @relation(fields: [userIds])
}

FYI, the linked issue won’t auto-fix M:N, but rather it will auto-fix the relation to be 1:N, then you can tweak it to be M:N. This is how we do it with SQL database support right now.

[janpio]

Please open a new issue @BoraALAP and provide all the information the bug report template asks for. Thanks.