As soon as we update from 1.4.0 to 1.4.1 (or further) we encounter an issue with a single type being referenced from a library. We’re in control of the library, the update from 1.4.0 to 1.4.1 is occurring in that library. Library:

api

type:

@Serializable
enum class ProductType {
    Cash, Loan, Prepaid, Monthly;
}

Consumer: pom.xml can use any of

1.4.0

,

1.4.1

or

1.5.0

. If

api

is at

1.4.0

we get no error, our application compiles fine. If

api

is at

1.4.1

or higher we get

Serializer has not been found for type 'ProductType?'. To use context serializer as fallback, explicitly annotate type or property with @Contextual

Initially I thought it might be related to this youtrack ticket, but ours continues to fail even if we remove the nullability. Has anyone seen this before?