Moshi: Deserializing extended Kotlin class

[LukasVykuka]

I'm trying to deserialize this JSON

{
  "derived_value": "foo",
  "parent_value": "bar"
}

with these classes

data class DerivedEntity(
    @Json(name = "derived_value") val derivedValue: String? = null
) : ParentEntity()

abstract class ParentEntity(
    @Json(name = "parent_value") val parentValue: String? = null
)

Result is instance of DerivedEntity class with values set to derivedValue = "foo" and parentValue = null.
It's possible to have parentValue also set to value from JSON?

(I'm able to achieve it by changing parentValue to var but I feel it's not correct solution.)

[NightlyNexus]

Working as intended.
Vals are read-only, so you probably want the parent_value as a constructor parameter or a var.
(Aside: Inheritance with value types is strange, and I'm surprised Kotlin data classes allow this behavior.)

[LukasVykuka]

Unfortunately our API send some common parameters in every response so inheritance was natural choice for me. At least var is working.

Thanks for answer, I think this issue can be closed.

[SpaceBison]

@LukasVykuka could you post a code example that worked for you?

[LukasVykuka]

@SpaceBison having parent parameter as var (not val) make it work

abstract class ParentEntity(
    @Json(name = "parent_value") var parentValue: String? = null
)

[SpaceBison]

@LukasVykuka do you use codegen to generate adapters or do you use the reflection-based runtime adapter factory?

[LukasVykuka]

@SpaceBison codegen

[SpaceBison]

I'm surprised that this worked for you. In my case, for classes such as these:

@JsonClass(generateAdapter = true)
class Subclass(@Json(name="subclassPropertyJsonName") val subclassProperty: String? = null) : Superclass()

codegen ignored the annotations on Superclass. It started working when I specified the annotation target in the constructor:

abstract class Superclass(@property:Json(name="superclassPropertyJsonName") var superclassProperty: String? = null)

or moved the property to the class' body:

abstract class Superclass {
    @Json(name="superclassPropertyJsonName") var superclassProperty: String? = null
}

Thanks anyway!

[LukasVykuka]

@SpaceBison ups, sorry, I forgot that in production code I don't use anotations because JSON parameters have same names ParentEntity. That's why it worked.

But thanks for your hints, they are useful.

[NightlyNexus]

@SpaceBison

I filed https://github.com/square/moshi/issues/700 for that.