Aqueduct ORM ManagedObject's transient property being persisted - dart

Question

I have an Aqueduct project using the ORM, with a data model as follows:
class _Thing {
#primaryKey
int id;
String first;
String second;
}
class Thing extends ManagedObject<_Thing> implements _Thing {
#Serialize()
OtherThing get firstAndSecond() {
// return some value computed from first and second
}
#Serialize()
set firstAndSecond(OtherThing firstAndSecond) {
// set first and second based on some computation
}
}
According to the docs for transient properties, annotating with #Serialize() should enable this model to be serialized/deserialized. It also says that properties in ManagedObjects are not persisted, but when I run the server, I get the error:
Data Model Error: Property 'firstAndSecond' on 'Thing' has an unsupported type.
If I remove the #Serialize(), it doesn't try to persist it, but I can't serialize/deserialize this object.
Any suggestions as to why this is happening or how I can control this behaviour?

Answer 1

This should be in the docs -
A Serializable property must be a primitive type (e.g. String, int, double, bool or a Map or List containing these types). Serializable values are passed directly to the codec that is reading from a request body or writing to a response body (by default, this codec is JSON). In the case of a custom type like OtherThing, the codec doesn't know how to encode or decode that type.
For complex types, you might use a map:
#Serialize()
Map<String, dynanic> get firstAndSecond() {
return {"first": first, "second": second};
}
You might also use CSV-like data:
#Serialize()
String get firstAndSecond() {
return "$first,$second";
}