Kotin 2.1.x seems to break the `asCache` extension functions

[mluiten]

When updating to Kotlin 2.1.20, the asCache extensions functions don't seem to resolve anymore and there seems to be no workaround that works for me... getting these types of errors:

[ERROR] <BLABLA>Service.kt:[60,10] None of the following candidates is applicable:
[ERROR] fun <K, V> Caffeine<in K, in V>.asCache(): Cache<K, V>
[ERROR] fun <K, V> Caffeine<in K, in V>.asCache(scope: CoroutineScope): Cache<K, V>

Could be related to https://kotlinlang.org/docs/whatsnew21.html#improved-overload-resolution-for-functions-with-generic-types ?

[wingsofovnia]

My code also breaks similarly. Can be reproduced by having a nullable cache value:

// Works
private val agreementCache = Caffeine.newBuilder().asCache<UUID, AgreementResponse>()

// Doesn't work: None of the following candidates is applicable
private val agreementCache = Caffeine.newBuilder().asCache<UUID, AgreementResponse?>()

On a separate note, having proper @ReplaceWith would have helped a lot.

[mluiten]

@wingsofovnia ah yes, that is a great addition! It indeed seems to be limited to nullable cache values

[tomaszym]

Workaround: wrap your cached value in an Option class (eg arrow's Option has nice integration with kotlin nullables https://arrow-kt.io/learn/immutable-data/optional/ )

[sven42]

Hello @sksamuel,

I have the same error as I wanted to update from v2.1.2 to v3.0.1 with kotlin 2.2.20:

With a nullable value I now get the following errors:

val envelopeCache: Cache<Id<Envelope>, Envelope?> = Caffeine.newBuilder().asCache()

• Type argument is not within its bounds: must be subtype of 'Any'.
• Initializer type mismatch: expected 'Cache<Id<Envelope>, Envelope?>', actual 'Cache<Any, Any>'.

Is this change intended? If yes, do you have a recommendation how to deal with nullable values?

Best regards,
Sven

[sksamuel]

Is this working in the latest release ?

[sven42]

It did not work with v3.0.1 (which currently is the latest release) and kotlin 2.2.20.

I have not retested with kotlin 2.2.21.