calling findUnique concurrently on a model with a compound unique constraint causes it to return null

[MichaelB-99]

Bug description

This bug occurs when running multiple findUnique queries with another non unique value (extendedWhereUnique) concurrently on a model with a compound unique constraint. It causes prisma to return null instead of the record.

• Only occurs when calling findUnique with the unique field and another non unique field
• Only occurs when the model has a @@unique() constraint
• Only occurs when findUnique queries are run concurrently
• Note that if filtering on the non unique value e.g deletedAt: { not:null }, we get the following rust error : tokio-runtime-worker' panicked at 'called Option::unwrap() on a None value', query-engine\core\src\response_ir\mod.rs:55:43

How to reproduce

I have made a repo with a reproduction here: https://github.com/MichaelB-99/prisma-bug-reproduction.

Expected behavior

That findUnique returns the record regardless of if it is run concurrently or not

Prisma information

generator client {
  provider        = "prisma-client-js"
  previewFeatures = ["extendedWhereUnique"]
}

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

model Post {
  id        Int
  userId    Int
  text      String
  deletedAt DateTime?

  @@unique([id, userId])
}

import { PrismaClient } from "@prisma/client";

async function main() {
  const prisma = new PrismaClient();
  await prisma.post.deleteMany({});
  await prisma.post.create({
    data: {
      id: 1,
      userId: 1,
      text: "Hello, world!",
    },
  });

  const queryPost = () =>
    prisma.post.findUnique({
      where: {
        id_userId: {
          id: 1,
          userId: 1,
        },
        // without non unique values the error doesn't occur
        deletedAt: null,
      },
    });

    
    // if we change the length to one to run this once then we get the expected result
  // {concurrent: [ { id: 1, userId: 1, text: 'Hello, world!', deletedAt: null } ]}

  const concurrent = await Promise.all(Array.from({ length: 2 }, queryPost));
  console.log({ concurrent });

  // { concurrent: [ null, null ] }
}

main().catch((e) => console.error(e));

Environment & setup

• OS: Windows 10
• Database: PostgreSQL,
• Node.js version: v17.9.0

Prisma Version

prisma                  : 4.5.0
@prisma/client          : 4.5.0
Current platform        : windows
Query Engine (Node-API) : libquery-engine 0362da9eebca54d94c8ef5edd3b2e90af99ba452 (at node_modules\@prisma\engines\query_engine-windows.dll.node)      
Migration Engine        : migration-engine-cli 0362da9eebca54d94c8ef5edd3b2e90af99ba452 (at node_modules\@prisma\engines\migration-engine-windows.exe)  
Introspection Engine    : introspection-core 0362da9eebca54d94c8ef5edd3b2e90af99ba452 (at node_modules\@prisma\engines\introspection-engine-windows.exe)
Format Binary           : prisma-fmt 0362da9eebca54d94c8ef5edd3b2e90af99ba452 (at node_modules\@prisma\engines\prisma-fmt-windows.exe)
Format Wasm             : @prisma/prisma-fmt-wasm 4.5.0-43.0362da9eebca54d94c8ef5edd3b2e90af99ba452
Default Engines Hash    : 0362da9eebca54d94c8ef5edd3b2e90af99ba452
Studio                  : 0.476.0
Preview Features        : extendedWhereUnique