Are i understand something wrong or it s kotlin bug I have d

Question

Are i understand something wrong or it s kotlin bug I have data class Foo val initializationType InitializationType val isInitDefault = initializationType == InitializationType Default and when i call this val it s working incorrect but when i transform it to fun or just add custom get = initializationType == InitializationType Default it start working like it should what the problem P S InitializationType it s enum

gildor · Answer

what exactly working incorrect Maybe your initializationType is mutable in your code Don t forget that isInitDefault caches result and do not update value on initializationType change Just show some example you can try to reproduce it on <http try kotlinlang org|try kotlinlang org> and share your code

Jacks0n23 · Answer

it s val

gildor · Answer

So maybe you could share some self contained example

Jacks0n23 · Answer

group fields any it fieldType initializationType == InitializationType Optional true group fields any it fieldType isInitOptional false

gildor · Answer

what is group and fields Is that reflections API

Jacks0n23 · Answer

no it s data classes

Jacks0n23 · Answer

it came from back

gildor · Answer

Oh so you use something like Gson to map backend response to data class

Jacks0n23 · Answer

yes

gildor · Answer

This is because of way how Gson works If your class do not have default constructor Gson uses sun misc Unsafe to create instance and set fields without calling constructor so your field not initialised

gildor · Answer

it s known problem of some Java only json mappers Use default constructor just add default values to all the properties or use default constructor compiler plugin Use some another solution for mapping json to classes that respects nullability and probably support Kotlin data classes moshi kotlin kotshi < C90AVCDQU|klaxon> kotlinx serialization < C7A1U5PTM|serialization> or something else don t know such libraries for Gson tho only Gson + AutoValue

gildor · Answer

Or use method getter extension function of course that doesn t have such problem

Jacks0n23 · Answer

ohh thank you very much

gildor · Answer

Also because of this default properties values don t work if you don t have default constructor be careful with this

gildor · Answer

and also Gson can write null to non null field because doesn t respect nullability