TypeError: model.collection.addQueue is not a function because property "collection" is overwritten when loading class and "collection" was provided in class

[Baumgaer]

version 5.12.8 worked fine and since 5.12.9 the following bug occures when building the schemas:

TypeError: model.collection.addQueue is not a function
     at D:\Atom_projects\ba\node_modules\mongoose\lib\model.js:1693:30
     at processTicksAndRejections (internal/process/task_queues.js:75:11)

I don't know how to reproduce this, but the logging on the tracebacks given position, following will be printed:

Line of code:

model.collection.addQueue(create, []);

logging: console.log(model, model.collection, model.collection.addQueue)

Result:

THE MODEL: Model { SystemUser }
THE COLLECTION: users
THE FUNCTION: undefined

The model SystemUser is derived from Model user and both have the same collection.
The collection "users" seems to be a String instead of a "NaviveCollection"-Object

Expected behavior is to queue the collection

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

Node: v12.13.0
mongoose: 5.12.9
MongoDB: 4.4.2 Community

[Baumgaer]

Found the reason. I had a static property called "collection" and I loaded the whole class to the model. So the loading has overwritten the models property "collection". Maybe there should be an error message which protects internal properties from overwrite or add a mapping to an alternative, internal choosen name.

[vkarpov15]

Any code in model.js that uses this.collection should use this.$__collection instead, and models should have both a collection and a $__collection property that point to the underlying collection object. We should use $__collection internally to minimize risk of conflicts, but we should leave collection for backwards compatibility.

[Baumgaer]

The same should be done with the property "schema" and all other properties which could be overwritten by loading a class into the schema.