Storing version references with layer entities?

[hrstoyanov]

I have this use case - I want to create a purchase that is linked to a specific version of a product. Therefore, if the product changes (price changes) the purchase will always be linked to the version of the product at the time when purchase was made. Is there a way to do that automatically?

With the code below, the purchase entity will always point to the lates product entity, which is wrong -m is this assumption correct? I know that layered entities can use versioned context, but it seems the current approach is to always explicitly refer to the version, can this be automatically done?

versionContext.versions(product).get(10L); //always have to refer to explicit version

here is some sample code:

import org.eclipse.serializer.entity.Entity;

interface  Product  extends Entity {
 ...
}

interface Purchase extends Entity {
   Product product();
}

void main () {

//Create version context
var versionContext = EntityVersionContext. AutoIncrementingLong();


//Product is created here, but can undergo many updates
var product = ProductCreator.New()
	.addLayer(versionContext)
	.name("Toyota")
	.price(123.01)
	.create();

// This wIll always point to the latest product, which is wrong for this use case
var purchase = PurchaseCreator.New()
	.product(product)
	.create();
}

[hrstoyanov]

Will this explicitly pin down the purchase to a specific version (last in this case)?

var purchase = PurchaseCreator.New()
	.product(versionContext.versions(product).last())
	.create();
}
;

Also, is versioning transitive - for example, if the product has a "cancellation policy" entity associated, will the purchase linked to a particular version of the product will transitively be also linked to the particular product's cancellation policy at the time of purchase?