Projection with '+' not including field (since v7.1.1)

[draperunner]

Prerequisites

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

Mongoose version

7.1.1

Node.js version

16.x, 18.x

MongoDB server version

4.4

Typescript version (if applicable)

No response

Description

This issue is very similar to this: #13340

7.1.1 is the first version that is bad. I have tested that 7.1.0 works, and that the latest version (7.4.4) also fails.

I have a Schema where one sub-document is not selected by default (select: false in schema definition). I have queries that needs this sub-document and therefore select it explicitly with the "+" syntax like so: .select("+myField").
The problem is that this field is not returned although being explicitly selected.

Note that one difference from #13340 is that now the other fields are included, just not the one that is selected. In #13340 only the _id was returned – no other fields.

Steps to Reproduce

This can be reproduced by running the following code with mongoose >= 7.1.1. See that age is not returned.

If you use mongoose 7.1.0, age is included in the response as expected.

const mongoose = require('mongoose');

async function main() {
  await mongoose.connect('mongodb://127.0.0.1:27017/test');

  const kittySchema = new mongoose.Schema({
      name: String,
      age: {
        select: false,
        type: Number
      }
    });

  const Kitten = mongoose.model('Kitten', kittySchema);
  const silence = new Kitten({ name: 'Silence', age: 2 });
  await silence.save()

  const updated = await Kitten.findByIdAndUpdate(silence._id, { age: 3 })
    .select("+age")

  console.log("UPDATED", updated) // <-- Returns _id, name and __v, but not age!
}

main()

Result from the console.log using mongoose 7.1.1:

UPDATED {
  _id: new ObjectId("64e674ea250a3fbd6b986c1c"),
  name: 'Silence',
  __v: 0
}

Result from the console.log using mongoose 7.1.0:

UPDATED {
  _id: new ObjectId("64e676bfd40527d1db7d3166"),
  name: 'Silence',
  age: 2,
  __v: 0
}

Expected Behavior

When using .select('+someField'), someField should be included in the response.

[draperunner]

Something also happened in v7.2.1 with find queries. age is returned as expected in 7.2.0, but is broken in 7.2.1:

Run the following code with v7.2.1 to see that age is not included:

const mongoose = require("mongoose");

async function main() {
  await mongoose.connect("mongodb://127.0.0.1:27017/test");

  const kittySchema = new mongoose.Schema({
    name: String,
    age: {
      select: false,
      type: Number,
    },
  });

  const Kitten = mongoose.model("Kitten", kittySchema);
  const silence = new Kitten({ name: "Silence", age: 2 });
  await silence.save();

  const cursor = Kitten.find().select("+age").cursor();

  for await (const kitten of cursor) {
    console.log(kitten);
  }

  mongoose.disconnect();
}

main();

This outputs:

{
  _id: new ObjectId("64e67ba65da08a10deff42a2"),
  name: 'Silence',
  __v: 0
}

While running with version 7.2.0 gives:

{
  _id: new ObjectId("64e67c3191569b0402e87d32"),
  name: 'Silence',
  age: 2,
  __v: 0
}

[IslandRhythms]

Mongoose 7.4.5 does not have this issue. Unable to reproduce.

const mongoose = require('mongoose');

async function main() {
  await mongoose.connect('mongodb://127.0.0.1:27017/test');

  const kittySchema = new mongoose.Schema({
      name: String,
      age: {
        select: false,
        type: Number
      }
    });

  const Kitten = mongoose.model('Kitten', kittySchema);
  const silence = new Kitten({ name: 'Silence', age: 2 });
  await silence.save()

  const updated = await Kitten.findByIdAndUpdate(silence._id, { age: 3 })
    .select("+age")

  console.log("UPDATED", updated) // <-- Returns _id, name and __v, but not age!
}

main()

UPDATED {
  _id: new ObjectId("64ee519258a712e851a47d50"),
  name: 'Silence',
  age: 2,
  __v: 0
}

[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

[draperunner]

I have tested again, and yes, findByIdAndUpdate now works with v7.4.5.

But not using cursor as I explained in my first comment!

The following code:

const mongoose = require("mongoose");

async function main() {
  await mongoose.connect("mongodb://127.0.0.1:27017/test");

  const kittySchema = new mongoose.Schema({
    name: String,
    age: {
      select: false,
      type: Number,
    },
  });

  const Kitten = mongoose.model("Kitten", kittySchema);
  const silence = new Kitten({ name: "Silence", age: 2 });
  await silence.save();

  const cursor = Kitten.find().select("+age").cursor();

  for await (const kitten of cursor) {
    console.log(kitten);
  }

  mongoose.disconnect();
}

main();

Returns

{
  _id: new ObjectId("6505714454789b1a5e9e3d62"),
  name: 'Silence',
  __v: 0
}

But the expected result is

{
  _id: new ObjectId("6505714454789b1a5e9e3d62"),
  name: 'Silence',
  age: 2,
  __v: 0
}