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The client fetches Scalar list fields as [] while they behave as if the value is NULL.

See original GitHub issue

Bug description

Item with scalar list field of value NULL comes as empty list from the prismaClient. This makes when consuming data, impossible to differentiate between empty lists and NULL value lists.

How to reproduce

Running:

const blogPost0 = await prismaClient.blogPost.create({});
const blogPost1 = await prismaClient.blogPost.create({ tags: [] });
console.log({ blogPost0, blogPost1 });

// Logs
// { 
//  blogPost0: {
//    "id": "3b7a0ff6-dbe5-450a-a10f-af9aa0f0adff",
//    "createdAt": "2022-06-16T15:23:19.856Z",
//    "tags": [],  // The item behaves as if the value is NULL, but is fetched as empty list.
//  },
//  blogPost1: {
//    "id": "248f05b8-590a-4342-af9b-651aa5831df0",
//    "createdAt": "2022-06-16T15:23:19.875Z",
//    "tags": [],
//  }
//}

const blogPostsWithoutTag = await prismaClient.blogPost.findMany({
  where: {
    tag: {
      isEmpty: true,
    },
  },
});
console.log(blogPostsWithoutTag);

// Logs
//  [{
//    "id": "248f05b8-590a-4342-af9b-651aa5831df0",
//    "createdAt": "2022-06-16T15:23:19.875Z",
//    "tags": [],
//  }]
// This proofs that the item 'blogPost0' behaves as if the value of the 'tag' field is 'NULL' and not an empty list.

Expected behavior

No response

Prisma information

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

generator client {
  provider = "prisma-client-js"
  output   = "../generated/client"
  previewFeatures = []
}

model BlogPost {
  id                   String               @id @default(uuid())
  createdAt            DateTime             @default(now())
  tags                 String[]
}