Default value for unknown Enum value

[cosminstefanxp]

In order to be forward-compatible and support certain scenarios, it would be useful to have a way to specify a default value for a deserialized Enum field, if an unknown value is encountered. That way, if a new type is defined and being returned by remote APIs, apps already in production will work properly in the intermediate period before migration.

Example:

enum class Status { ACTIVE, INACTIVE, UNKNOWN }
class Test(val status: Status = Status.UNKNOWN)

would return a Test(UNKNOWN) when provided with the following json: {'status': 'PENDING'}

[simonovvasiliy]

Good use case, Jackson can do it and we rely its feature

[avently]

@sandwwraith
A year is gone. Any news related to enums?

[sandwwraith]

@avently Not yet

[Larsmyrup]

This would be really useful. Does anyone know if this will be implemented?

[santoshastagi]

This is important for us too. Any other ways to do this?

[ManuelDCR]

This would be a really appreciated feature!
Any news @sandwwraith ?

[arberg]

This is just to help others who need to solve this issue here and now: Bolinfest showed us how to do create a custom serializer here on issue #31

[igrmk]

For those who need a solution here is a complete answer.
https://github.com/igrmk/smsq/blob/532e3468266c8fc319c8ecca11be76f7026949a7/android/app/src/main/java/com/github/igrmk/smsq/entities/DeliveryResult.kt

[azabost]

If you are interested in even better forward compatibility of enums, I would recommend using a wrapper like this: https://github.com/bright/codified. I have been using it for a quite long time and it works beautifully. Feel free to let me know what you think about it 😊

[tagy]

Enabling coerceInputValues and setting default enum values in you class was easiest way to solve this at the moment I think.

[arberg]

For those who need a solution here is a complete answer. https://github.com/igrmk/smsq/blob/532e3468266c8fc319c8ecca11be76f7026949a7/android/app/src/main/java/com/github/igrmk/smsq/entities/DeliveryResult.kt

I updated this example by @igrmk, and made it generic: https://gist.github.com/arberg/e20db05e018c61f37f1d274a254657c3

The code above annotates the enum-class with something like @Serializable(with = TestEnumSerializer::class), and it has the advantage that classes that use the enum does not have to do anything special. This is great, because when reviewing code for correctness we only have to review the enum-class and its annotation, not every single file that uses it now (or in the future).