Mongoose: Populate multiple nested Virtuals not working

[simonepri]

I have the following Schemas:

var TripSchema = new mongoose.Schema({
  ...
});
TripSchema.virtual('Orders', {
  ref: 'Order',
  localField: '_id',
  foreignField: 'trip_id'
});
var OrderSchema = new mongoose.Schema({
  'trip_id': {type: mongoose.Schema.Types.ObjectId, required: true},
  'vehicle_id': {type: mongoose.Schema.Types.ObjectId, required: true},
  ....
});
OrderSchema.virtual('Vehicle', {
  ref: 'Vehicle',
  localField: 'vehicle_id',
  foreignField: '_id',
  justOne: true
});
var VehicleSchema = new mongoose.Schema({
  ...
});

var Order = mongoose.model('Order', OrderSchema);
var Trip = mongoose.model('Trip', TripSchema);
var Vehicle = mongoose.model('Vehicle', VehicleSchema);

And i'm trying to populate it querying from a Trip model:

var self = this; // <-- suppose we are inside a TripSchema.statics.someFuncName
var trip_id = "XXXXXXXXXXXXXXXXXX";
var populate = [{
    path: 'Orders',
    populate: {
      path: 'Vehicle'
    }
}];
self.findById(trip_id).populate(populate).exec(function(err, trip) {
  // trip.Orders is correctly populated with an array of Order as expected
  // trip.Orders[x].Vehicle is not populated
}

But is not properly populated.

Oviusly if I try to populate 'vehicle_id' instead of 'Vehicle' it works, but i want to use the Virtuals if possible.

Also i didn't find the documentation about this use of Virtuals anywhere.

Thanks.

Related:

4219 , #2562 , #4348 , #4354

[simonepri]

The features works. It was a problem related to a thing external to mongoose.
I close the issue.

@vkarpov15 I think this could be useful for someone as example of how to use nested virtuals. I think that something like this should be added to the documentation.

Regards,
Simone