I've tried compiling KVision with K2 and get error...

# k2-adopters

[Robert Jaros]

I've tried compiling KVision with K2 and get errors on compiling this class: https://github.com/rjaros/kvision/blob/master/kvision-modules/kvision-server-javalin/src/jvmMain/kotlin/io/kvision/remote/KVServiceManager.kt

[Robert Jaros]

I'm using 1.9.20

[Robert Jaros]

This is the stacktrace https://pastebin.com/7SzG9qUC

[Robert Jaros]

Does it look like a known issue?

[dmitriy.novozhilov]

Could you please check it with 2.0.0-Beta1, which was released today?

[Robert Jaros]

It doesn't crash with 2.0.0-Beta1. It still doesn't compile but there is a normal error message.

[Robert Jaros]

Still I'm not sure how to address this issue. The compiler doesn't allow default values in my expect declarations:

Default argument values inside expect declaration 'KVServiceManager' are not allowed for methods actualized via fake override. Possible fix is to remove default argument values in members

[dmitriy.novozhilov]

cc @bobko

[Robert Jaros]

But I can't have default values in my actuals as well:

The following declaration is incompatible because actual function cannot have default argument values, they should be declared in the expected function

[Robert Jaros]

Any way to fix this other then dropping default values (which seems to work but I don't like this at all 😉) ?

[bobko]

> Default argument values inside expect declaration 'KVServiceManager' are not allowed for methods actualized via fake override. Possible fix is to remove default argument values in members...
@Robert Jaros can you please post the full compilation message? The compilation message mentions members at the end (the members are enumerated on new lines). I'm interested in the member names

It's this issue: https://youtrack.jetbrains.com/issue/KT-62036

[Robert Jaros]

e: file:///home/rjaros/git/kvision/kvision-modules/kvision-server-javalin/src/jsMain/kotlin/io/kvision/remote/KVServiceManager.kt:29:95 Default argument values inside expect declaration 'KVServiceManager' are not allowed for methods actualized via fake override. Possible fix is to remove default argument values in members:
    expect fun <reified RET> bind(noinline function: suspend T.() -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR, reified RET> bind(noinline function: suspend T.(PAR) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1, reified PAR2, reified RET> bind(noinline function: suspend T.(PAR1, PAR2) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1, reified PAR2, reified PAR3, reified RET> bind(noinline function: suspend T.(PAR1, PAR2, PAR3) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1, reified PAR2, reified PAR3, reified PAR4, reified RET> bind(noinline function: suspend T.(PAR1, PAR2, PAR3, PAR4) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1, reified PAR2, reified PAR3, reified PAR4, reified PAR5, reified RET> bind(noinline function: suspend T.(PAR1, PAR2, PAR3, PAR4, PAR5) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1, reified PAR2, reified PAR3, reified PAR4, reified PAR5, reified PAR6, reified RET> bind(noinline function: suspend T.(PAR1, PAR2, PAR3, PAR4, PAR5, PAR6) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1 : Any, reified PAR2 : Any> bind(noinline function: suspend T.(ReceiveChannel<PAR1>, SendChannel<PAR2>) -> Unit, route: String? = ...): Unit

    expect fun <reified PAR : Any> bind(noinline function: suspend T.(SendChannel<PAR>) -> Unit, route: String? = ...): Unit

    expect fun <reified RET> bindTabulatorRemote(noinline function: suspend T.(Int?, Int?, List<RemoteFilter>?, List<RemoteSorter>?, String?) -> RemoteData<RET>, route: String? = ...): Unit

[Robert Jaros]

And the other one - for JVM target:

[Robert Jaros]

e: file:///home/rjaros/git/kvision/kvision-modules/kvision-server-javalin/src/jvmMain/kotlin/io/kvision/remote/KVServiceManager.kt:58:5 Default argument values inside expect declaration 'KVServiceManager' are not allowed for methods actualized via fake override. Possible fix is to remove default argument values in members:
    expect fun <reified RET> bind(noinline function: suspend T.() -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR, reified RET> bind(noinline function: suspend T.(PAR) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1, reified PAR2, reified RET> bind(noinline function: suspend T.(PAR1, PAR2) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1, reified PAR2, reified PAR3, reified RET> bind(noinline function: suspend T.(PAR1, PAR2, PAR3) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1, reified PAR2, reified PAR3, reified PAR4, reified RET> bind(noinline function: suspend T.(PAR1, PAR2, PAR3, PAR4) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1, reified PAR2, reified PAR3, reified PAR4, reified PAR5, reified RET> bind(noinline function: suspend T.(PAR1, PAR2, PAR3, PAR4, PAR5) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1, reified PAR2, reified PAR3, reified PAR4, reified PAR5, reified PAR6, reified RET> bind(noinline function: suspend T.(PAR1, PAR2, PAR3, PAR4, PAR5, PAR6) -> RET, method: HttpMethod = ..., route: String? = ...): Unit

    expect fun <reified PAR1 : Any, reified PAR2 : Any> bind(noinline function: suspend T.(ReceiveChannel<PAR1>, SendChannel<PAR2>) -> Unit, route: String? = ...): Unit

    expect fun <reified PAR : Any> bind(noinline function: suspend T.(SendChannel<PAR>) -> Unit, route: String? = ...): Unit

    expect fun <reified RET> bindTabulatorRemote(noinline function: suspend T.(Int?, Int?, List<RemoteFilter>?, List<RemoteSorter>?, String?) -> RemoteData<RET>, route: String? = ...): Unit

[Robert Jaros]

Not sure if both are identical

[bobko]

Minimized example:

// COMMON
expect open class KVServiceManager {
    protected inline fun bind(route: String? = null)
}

// PLATFORM
open class KVServiceBinder {
    internal inline fun bind(route: String?) {}
}
actual open class KVServiceManager : KVServiceBinder()

I confirm that it's exactly what we prohibited in https://youtrack.jetbrains.com/issue/KT-62036 because it wasn't properly supported.

Right now, I can only advise a workaround to declare an overload with substituted default args (the workaround is mentioned in the issue).

If we see that this prohibition breaks a lot of code we might want to reconsider, so thanks for letting us know. But until then we'd like to keep it prohibited (expect/actual classes is a Beta feature, that's why we can do that)

[Robert Jaros]

Thanks for the explanation. I should be able to deal with this issue now.