findOneAndUpdate with upsert option won't respect "_id: String"

[eric-burel]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Mongoose version

6.4.5

Node.js version

16.15.0

MongoDB server version

4.0.4

Description

The inserted document will have an "ObjectId" _id despite using _id: String in a schema.

new mongoose.Schema({ _id: String }, { strict: false })

Steps to Reproduce

• Create a new model with _id: String in the schema

const schema = new Schema({ _id: String }, { strict: false});
const MyModel = mongoose.model('MyModel', schema);

• Use findOneAndUpdate with upsert option to create a new document:

// since the doc doesn't exist, it will be inserted thanks to the upsert option
    const res =
      await MyModel.findOneAndUpdate(
        { foo: "bar" },
        {},
        { upsert: true, returnDocument: "after" }
      );

The document will have an ObjectId _id, the String type is not respected.

Expected Behavior

The new document should have a string _id.

[IslandRhythms]

const mongoose = require('mongoose');

const testSchema = new mongoose.Schema({
    _id: String
}, { strict: false })

const Test = mongoose.model('Test', testSchema);

async function run() {
    await mongoose.connect('mongodb://localhost:27017');
    await mongoose.connection.dropDatabase();

    const entry = await Test.create({
        _id: 'Test Testerson'
    });

    console.log(entry, entry._id, typeof entry._id);

    const test = await Test.findOneAndUpdate({foo: 'bar'}, {}, {upsert: true, returnDocument: "after"});
    console.log(test, test._id, typeof test._id)
}

run();

[github-actions]

This issue is stale because it has been open 14 days with no activity. Remove stale label or comment or this will be closed in 5 days

[github-actions]

This issue was closed because it has been inactive for 19 days since being marked as stale.