BigInt becomes Number if queried with `$queryRaw`

Bug description

When I try to $queryRaw() a BigInt column, it becomes Number, resulting in loss of precision for greater number than Number.MAX_SAFE_INTEGER.

// This user has ID of `BigInt(1)` with schema written below.
await prisma.user.create({
  data: { name: 'dummy' },
})

const user1 = (await prisma.user.findFirst()) as User
// This output `true`, as expected
console.log({ user: user1, isSame: user1.id === BigInt(1) })

const [user2] = await prisma.$queryRaw<User[]>`SELECT id, name FROM "User"`
// However, this output `false`, as `typeof user2.id === 'number'`
console.log({ user: user2, isSame: user2.id === BigInt(1) })

How to reproduce

I created a minimal reproduction repository of this issue.

$ git clone https://github.com/yukidaruma/prisma-bigint-rawquery
$ cd prisma-bigint-rawquery
$ npm i
$ docker-compose up -d
$ npx prisma migrate dev --name bigint_rawquery_test
$ npm run dev

> dev
> ts-node ./script.ts

{ user: { id: 1n, name: 'dummy' }, isSame: true } // Using `findFirst()` method
{ user: { id: 1, name: 'dummy' }, isSame: false } // Using `$queryRaw()` method 

Expected behavior

I expect $queryRaw() to handle BigInt column properly, returning BigInt value instead of Number value.

{ user: { id: 1n, name: 'dummy' }, isSame: true } // Using `findFirst()` method
{ user: { id: 1n, name: 'dummy' }, isSame: true } // Using `$queryRaw()` method

Prisma information

// Can be found at: https://github.com/yukidaruma/prisma-bigint-rawquery/blob/main/prisma/schema.prisma

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}

generator client {
  provider = "prisma-client-js"
}

model User {
  id   BigInt @id @default(autoincrement())
  name String
}

Environment & setup

• OS: Windows
• Database: PostgreSQL 13.3 (with postgres:13.3-alpine Docker image)
• Node.js version: v16.1.0

Prisma Version

Environment variables loaded from prisma\.env
prisma               : 2.23.0
@prisma/client       : 2.23.0
Current platform     : windows
Query Engine         : query-engine adf5e8cba3daf12d456d911d72b6e9418681b28b (at node_modules\@prisma\engines\query-engine-windows.exe)
Migration Engine     : migration-engine-cli adf5e8cba3daf12d456d911d72b6e9418681b28b (at node_modules\@prisma\engines\migration-engine-windows.exe)
Introspection Engine : introspection-core adf5e8cba3daf12d456d911d72b6e9418681b28b (at node_modules\@prisma\engines\introspection-engine-windows.exe)
Format Binary        : prisma-fmt adf5e8cba3daf12d456d911d72b6e9418681b28b (at node_modules\@prisma\engines\prisma-fmt-windows.exe)
Default Engines Hash : adf5e8cba3daf12d456d911d72b6e9418681b28b
Studio               : 0.393.0

[gersmann]

Too bad I had to find out about this after migrating quite some logic to Prisma in dev. Any chance that there will be a fix for this soon? This is critical.

[Weakky]

Hey,

This issue was fixed by https://github.com/prisma/prisma-engines/pull/2847. It will be available in the next release under the improvedQueryRaw feature flag.

Beware that enabling improvedQueryRaw is a breaking change. Release notes will contain information as to how to upgrade (so will the documentation).

Thanks for reporting 🙏