Missing breaking change in v6 changelog: schema no longer inherits minimize option

[ZhangYiJiang]

Do you want to request a feature or report a bug?

Bug

What is the current behavior?

In v5, the minimize option seem to be inherited by child schema. This is no longer the case in v6. This should be considered at least a bug in the changelog

v5 -

> const { Schema, model, version } = require('mongoose');
> console.log(version);
5.9.29
> const child = new Schema({ thing: Schema.Types.Mixed });
> const parent = new Schema({ child }, { minimize: false });
> const Parent = model('Parent', parent);
> const p = new Parent({ child: { thing: {} } });
> console.log(p.toObject());
{
  _id: 615670e7ce0fe77733511fa8,
  child: { _id: 615670e7ce0fe77733511fa9, thing: {} }
}

v6 -

> const { Schema, model, version } = require('mongoose');
> console.log(version);
6.0.6
> const child = new Schema({ thing: Schema.Types.Mixed });
> const parent = new Schema({ child }, { minimize: false });
> const Parent = model('Parent', parent);
> const p = new Parent({ child: { thing: {} } });
> console.log(p.toObject());
{
  child: { _id: new ObjectId("615670bbd7853d32111ae88e") },
  _id: new ObjectId("615670bbd7853d32111ae88d")
}

For easier copy-pasting -

const { Schema, model, version } = require('mongoose');
console.log(version);
const child = new Schema({ thing: Schema.Types.Mixed });
const parent = new Schema({ child }, { minimize: false });
const Parent = model('Parent', parent);
const p = new Parent({ child: { thing: {} } });
console.log(p.toObject());

If the current behavior is a bug, please provide the steps to reproduce.

What is the expected behavior?

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.

[IslandRhythms]

So on newer versions of 5 thing does not show up.

[vkarpov15]

I took a closer look and this is expected behavior as of v5.10.5 with #9405. This is not a change in v6. As a workaround, you can either explicitly set minimize by calling toObject({ minimize: false }), or, in 6.0, you can define schemas inline (without new Schema()) so the schema inherits its parent's minimize:

const { Schema, model, version } = require('mongoose');
console.log(version);
const parent = new Schema({ child: { thing: Schema.Types.Mixed } }, { minimize: false });
const Parent = model('Parent', parent);
const p = new Parent({ child: { thing: {} } });
console.log(p.toObject()); // Contains `thing` in v6.x

[nomcopter]

Sure, if it is expected behavior then this is instead an undocumented breaking change introduced in a patch version.

[vkarpov15]

@nomcopter correct. This change was meant to be a bug fix, but sometimes bug fixes break code :( Do you need any help getting a workaround or do you just think there should be a note in the 6.0 changelog?

[nomcopter]

@vkarpov15 a note in the 6.0 changelog should cover it well at this point!