findUnique used with Promise.all returns null

[thomasjiangcy]

Bug description

There is an unexpected behaviour with .findUnique() and Promise.all() similar to #4438.

When used together, it returns an array of null:

// Assuming these IDs exist in the DB
await Promise.all(
  [1n, 2n, 3n].map(async (id) => await prisma.user.findUnique({
    where: {
      id
    }
  })
);

// Returns [null, null, null]

However, using .findUniqueOrThrow() with Promise.all() seems to work as expected.

---

How to reproduce

Here's a minimally reproducible repository - https://github.com/thomasjiangcy/prisma-promise-all-find-unique-bug

1. Clone the repository
2. npm install
3. docker compose up -d (if you have docker compose installed, if not you can run postgres another way)
4. npx prisma migrate dev
5. npx ts-node index.ts

Output of DEBUG='*' npx ts-node index.ts

  prisma:tryLoadEnv  Environment variables loaded from /Users/thomasjiang/Projects/prisma-promise-all-find-unique-bug/.env +0ms
  prisma:tryLoadEnv  Environment variables loaded from /Users/thomasjiang/Projects/prisma-promise-all-find-unique-bug/.env +2ms
  prisma:client  dirname /Users/thomasjiang/Projects/prisma-promise-all-find-unique-bug/node_modules/.prisma/client +0ms
  prisma:client  relativePath ../../../prisma +0ms
  prisma:client  cwd /Users/thomasjiang/Projects/prisma-promise-all-find-unique-bug/prisma +0ms
  prisma:client  clientVersion 4.10.1 +0ms
  prisma:client  clientEngineType library +0ms
  prisma:client:libraryEngine  internalSetup +0ms
  prisma:client:libraryEngine:loader  Searching for Query Engine Library in /Users/thomasjiang/Projects/prisma-promise-all-find-unique-bug/node_modules/.prisma/client +0ms
  prisma:client:libraryEngine:loader  loadEngine using /Users/thomasjiang/Projects/prisma-promise-all-find-unique-bug/node_modules/.prisma/client/libquery_engine-darwin-arm64.dylib.node +0ms
  prisma:client:libraryEngine  library starting +13ms
  prisma:client:libraryEngine  library started +44ms
  prisma:client  Prisma Client call: +68ms
  prisma:client  prisma.connection.create({
  data: {
    name: 'Connection 1',
    user: {
      create: {
        name: 'User 1'
      }
    }
  }
}) +1ms
  prisma:client  Generated request: +0ms
  prisma:client  mutation {
  createOneConnection(data: {
    name: "Connection 1"
    user: {
      create: {
        name: "User 1"
      }
    }
  }) {
    id
    name
    userId
  }
}
 +0ms
  prisma:client:libraryEngine  sending request, this.libraryStarted: true +12ms
  prisma:client  Prisma Client call: +31ms
  prisma:client  prisma.connection.create({
  data: {
    name: 'Connection 2',
    user: {
      create: {
        name: 'User 2'
      }
    }
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  mutation {
  createOneConnection(data: {
    name: "Connection 2"
    user: {
      create: {
        name: "User 2"
      }
    }
  }) {
    id
    name
    userId
  }
}
 +0ms
  prisma:client:libraryEngine  sending request, this.libraryStarted: true +30ms
  prisma:client  Prisma Client call: +4ms
  prisma:client  prisma.connection.create({
  data: {
    name: 'Connection 3',
    user: {
      create: {
        name: 'User 3'
      }
    }
  }
}) +1ms
  prisma:client  Generated request: +0ms
  prisma:client  mutation {
  createOneConnection(data: {
    name: "Connection 3"
    user: {
      create: {
        name: "User 3"
      }
    }
  }) {
    id
    name
    userId
  }
}
 +0ms
  prisma:client:libraryEngine  sending request, this.libraryStarted: true +5ms
  prisma:client  Prisma Client call: +3ms
  prisma:client  prisma.connection.create({
  data: {
    name: 'Connection 4',
    user: {
      create: {
        name: 'User 4'
      }
    }
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  mutation {
  createOneConnection(data: {
    name: "Connection 4"
    user: {
      create: {
        name: "User 4"
      }
    }
  }) {
    id
    name
    userId
  }
}
 +0ms
  prisma:client:libraryEngine  sending request, this.libraryStarted: true +4ms
  prisma:client  Prisma Client call: +4ms
  prisma:client  prisma.connection.create({
  data: {
    name: 'Connection 5',
    user: {
      create: {
        name: 'User 5'
      }
    }
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  mutation {
  createOneConnection(data: {
    name: "Connection 5"
    user: {
      create: {
        name: "User 5"
      }
    }
  }) {
    id
    name
    userId
  }
}
 +0ms
  prisma:client:libraryEngine  sending request, this.libraryStarted: true +3ms
  prisma:client  Prisma Client call: +4ms
  prisma:client  prisma.connection.findMany(undefined) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  query {
  findManyConnection {
    id
    name
    userId
  }
}
 +0ms
  prisma:client:libraryEngine  sending request, this.libraryStarted: true +4ms
  prisma:client  Prisma Client call: +3ms
  prisma:client  prisma.user.findUnique({
  where: {
    id: '1'
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  query {
  findUniqueUser(where: {
    id: 1
  }) {
    id
    name
  }
}
 +0ms
  prisma:client  Prisma Client call: +0ms
  prisma:client  prisma.user.findUnique({
  where: {
    id: '2'
  }
}) +1ms
  prisma:client  Generated request: +0ms
  prisma:client  query {
  findUniqueUser(where: {
    id: 2
  }) {
    id
    name
  }
}
 +0ms
  prisma:client  Prisma Client call: +0ms
  prisma:client  prisma.user.findUnique({
  where: {
    id: '3'
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  query {
  findUniqueUser(where: {
    id: 3
  }) {
    id
    name
  }
}
 +0ms
  prisma:client  Prisma Client call: +0ms
  prisma:client  prisma.user.findUnique({
  where: {
    id: '4'
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  query {
  findUniqueUser(where: {
    id: 4
  }) {
    id
    name
  }
}
 +0ms
  prisma:client  Prisma Client call: +0ms
  prisma:client  prisma.user.findUnique({
  where: {
    id: '5'
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  query {
  findUniqueUser(where: {
    id: 5
  }) {
    id
    name
  }
}
 +0ms
  prisma:client:libraryEngine  requestBatch +4ms
[ null, null, null, null, null ]
  prisma:client  Prisma Client call: +5ms
  prisma:client  prisma.user.findUniqueOrThrow({
  where: {
    id: '1'
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  query {
  findUniqueUserOrThrow(where: {
    id: 1
  }) {
    id
    name
  }
}
 +0ms
  prisma:client  Prisma Client call: +0ms
  prisma:client  prisma.user.findUniqueOrThrow({
  where: {
    id: '2'
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  query {
  findUniqueUserOrThrow(where: {
    id: 2
  }) {
    id
    name
  }
}
 +0ms
  prisma:client  Prisma Client call: +0ms
  prisma:client  prisma.user.findUniqueOrThrow({
  where: {
    id: '3'
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  query {
  findUniqueUserOrThrow(where: {
    id: 3
  }) {
    id
    name
  }
}
 +0ms
  prisma:client  Prisma Client call: +0ms
  prisma:client  prisma.user.findUniqueOrThrow({
  where: {
    id: '4'
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  query {
  findUniqueUserOrThrow(where: {
    id: 4
  }) {
    id
    name
  }
}
 +0ms
  prisma:client  Prisma Client call: +0ms
  prisma:client  prisma.user.findUniqueOrThrow({
  where: {
    id: '5'
  }
}) +0ms
  prisma:client  Generated request: +0ms
  prisma:client  query {
  findUniqueUserOrThrow(where: {
    id: 5
  }) {
    id
    name
  }
}
 +0ms
  prisma:client:libraryEngine  requestBatch +6ms
[
  { id: 1n, name: 'User 1' },
  { id: 2n, name: 'User 2' },
  { id: 3n, name: 'User 3' },
  { id: 4n, name: 'User 4' },
  { id: 5n, name: 'User 5' }
]
  prisma:client:libraryEngine  library stopping +56ms
  prisma:client:libraryEngine  library stopped +0ms
  prisma:client:libraryEngine:exitHooks  exit event received: beforeExit +0ms
  prisma:client:libraryEngine:exitHooks  exit event received: exit +0ms

Expected behavior

Using .findUnique() with Promise.all() should return an array of unique objects.

Prisma information

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

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

model User {
  id    BigInt  @id @default(autoincrement())
  name  String  @db.VarChar(255)

  connections Connection[]
}

model Connection {
  id      BigInt  @id @default(autoincrement())
  name    String  @db.VarChar(255)
  userId  BigInt
  user    User    @relation(fields: [userId], references: [id], onDelete: NoAction, onUpdate: NoAction)
}

import { PrismaClient } from '@prisma/client'

const prisma = new PrismaClient()

async function main() {
  for (let i = 0; i < 5; i++) {
    await prisma.connection.create({
      data: {
        name: `Connection ${i + 1}`,
        user: {
          create: {
            name: `User ${i + 1}`
          }
        }
      }
    });
  }

  const allConnections = await prisma.connection.findMany();
  const allConnectionTeamMembers_promiseAllFindUnique = await Promise.all(allConnections.map(async connection => await prisma.user.findUnique({
    where: {
      id: connection.userId
    }
  })));
  console.log(allConnectionTeamMembers_promiseAllFindUnique);

  const allConnectionTeamMembers_promiseAllFindUniqueOrThrow = await Promise.all(allConnections.map(async connection => await prisma.user.findUniqueOrThrow(({
    where: {
      id: connection.userId
    }
  }))));
  console.log(allConnectionTeamMembers_promiseAllFindUniqueOrThrow);
}

main()
  .then(async () => {
    await prisma.$disconnect()
  })
  .catch(async (e) => {
    console.error(e)
    await prisma.$disconnect()
    process.exit(1)
  })

Environment & setup

• OS: macOS 13.2.1
• Database: PostgreSQL 14.3
• Node.js version: v19.6.1

Prisma Version

prisma                  : 4.10.1
@prisma/client          : 4.10.1
Current platform        : darwin-arm64
Query Engine (Node-API) : libquery-engine aead147aa326ccb985dcfed5b065b4fdabd44b19 (at node_modules/@prisma/engines/libquery_engine-darwin-arm64.dylib.node)
Migration Engine        : migration-engine-cli aead147aa326ccb985dcfed5b065b4fdabd44b19 (at node_modules/@prisma/engines/migration-engine-darwin-arm64)
Format Wasm             : @prisma/prisma-fmt-wasm 4.10.1-1.80b351cc7c06d352abe81be19b8a89e9c6b7c110
Default Engines Hash    : aead147aa326ccb985dcfed5b065b4fdabd44b19
Studio                  : 0.481.0

[reteps]

Just lost my mind over this, thank you ❤️

[EduardoBautista]

This is also an issue when trying to use findUnique to avoid N+1 calls in GraphQL field resolvers. So it might be related to batching?

[nic-rod]

Also running into this - seems like a pretty significant issue. Seeing the issue on 4.7.1.

[janpio]

I can confirm this observation with the provided reproduction repository. Thanks for that @thomasjiangcy.

[aqrln]

I can reproduce this when the type of id is BigInt but not when it is Int.

[Nickersoft]

Not sure if this is related, but after upgrade to 4.10.0+ I'm seeing null get returned randomly for standalone findUnique calls that previously worked fine. Sometimes the call returns a value, other times null. I output the raw SQL via Prisma logging, ran it in my database manager, and was able to get rows back. I'm currently stuck on 4.9.0 as a result.

Edit: Just saw @EduardoBautista's comment regarding batching, which I am using. Surprised this is being seeing on versions 4.9.0 and below, though.

[nik-lampe]

We're having the same issue since upgrading to 4.10.
With 4.9. it works fine, like @Nickersoft commented.

Is there a way to disable the batching?
Otherwise we'll just stick to 4.9 until this is resolved :)

[moishinetzer]

I'm seeing this issue on prisma version 5.1.1

Update: This is enum related

[janpio]

Can you open a new issue @moishinetzer, optimally with a reproduction so we can observe this ourselves? Thanks.

[moishinetzer]

Sorry for not updating: It seems to be resolved now. My dependencies weren't matching between prisma and @prisma/client thanks for the help.