Objects with computed properties returned from an extended prisma client return true for any property name when calling hasOwn or hasOwnProperty on it

[ludwigbacklund]

Bug description

Objects with computed properties returned from an extended prisma client return true for any property name when calling .hasOwn or .hasOwnProperty on it.

Spreading the returned object into a new object and then running .hasOwn or .hasOwnProperty again with any property name works as expected, returning false for names that don't exist in the object.

Does this have something to do with the returned object being a proxy when it has a computed property from $extends on it?

How to reproduce

1. Git clone this repro repo: https://github.com/ludwigbacklund/prisma-hasown-bug-repro (it is based on your rest-nextjs-api-routes example)
2. Create a draft post
3. Go to the index page and check the server console

OR

Run the following code (replace post with any prisma model)

const testExtension = Prisma.defineExtension((client) => {
  return client.$extends({
    result: { post: { computed: { needs: {}, compute: () => 'whatever' } } },
  });
});

const prisma = new PrismaClient({
  datasources: { db: { url: 'SOME_DB_URL' } },
}).$extends(testExtension);

const post = await prisma.post.findFirst();
console.log(Object.hasOwn(post, 'this should not return true but it does')); // -> true
console.log(post.hasOwnProperty('this should not return true but it does')); // -> true

Expected behavior

.hasOwn and .hasOwnProperty should not always return true, only when the property name actually exists on the returned object.

Prisma information

model Post {
  id     String @id @default(cuid())
  title  String
  text   String
  userId String @map("user_id")

  user User @relation(fields: [userId], references: [id], onDelete: Cascade)

  createdAt DateTime @default(now()) @map("created_at")
  updatedAt DateTime @default(now()) @updatedAt @map("updated_at")

  @@map("posts")
}

Environment & setup

• OS: macOS Ventura 13.0
• Database: PostgreSQL 14
• Node.js version: 18.11.0

Prisma Version

5.11.0

[ludwigbacklund]

Tried reproducing in a fresh prisma example repo but cannot... not sure what is going on here.

[ludwigbacklund]

Okay I narrowed it down to client extensions adding computed properties to an object makes it act this way. It's all yours prisma team! 🙏