Does the "hidden classes" feature of JVM 15 have potential improve Kotlin on the JVM?

Hello everyone, after updating to Kotlin 1.4.10 i realized, that the

SerialName

annotation was set to

retention(BINARY)

Is there any way in Kotlin 1.4 to retrieve the

SerialName

of an annotated property? Because the way by reflection is now lost.

Is there a way to override a property getter so that the backing field is

const

? I.e.

(FooFeature as Feature).id

uses the property getter and

FooFeature.id

uses the compile-time constant

Hey dudes! Do i got it wrong, or the loadKoinModules works lazy ?

Hey all, looking for an equivalent of android’s Base64InputStream I can use server-side. Is anyone aware of any open source implementations?

Hi all is it possible to get the class type of the lambda ? something like

((String) -> String)::class

how come smart casting doesn't work here? i get

unresolved reference: value

for the

is Match.HasMatch

line

sealed class Match {
    object NoMatch : Match()
    class HasMatch(value: Int) : Match()
}

fun main() {
    val x: Match? = null

    when (x) {
        Match.NoMatch -> println("no match")
        is Match.HasMatch -> println("value: ${x.value}")
        null -> println("null")
    }
}

What is the appropriate way to write tests for an application that builds a command line tool (using

kotlinx.cli

)? The app itself looks pretty typical, e.g.:

fun main(args: Array<String>) {
   // Do stuff that might exit with status code 0 or 1
}

My (apparently wrong) instinct was to write tests like:

@Test fun testExitsWithoutError() {
   val result = main(args)
   assertEquals(0, result)
}

But

main

can only return

void

. How do I write tests that can pass args into main and expect a certain result?

What channel is best for discussing Jetpack DataStore?

My current data model uses nullables and a state property to handle the objects state

data class Model(
    val a: String,
    val b: String,
    val nullableOnlyForStateA: String?,
    val state: State,
    val propForStateA: String?,
    val propForStateB: String?
)

I’m trying to use sealed classes to make it more idiomatic but it seems too verbose:

sealed class Model {
    abstract val a: String
    abstract val b: String
    abstract val nullableOnlyForStateA: String?

    data class A(
        override val a: String,
        override val b: String,
        override val nullableOnlyForStateA: String?,
        val propForStateA: String
    ) : Model()

    data class B(
        override val a: String,
        override val b: String,
        override val nullableOnlyForStateA: String,
        val propForStateB: String
    ) : Model()
}

This seems okay but my original class has much more properties and more states making a 16-line data class turn into a more-than-100 line sealed class. Any ideas on how to make this more ergonomic?

Hi all, wondering whether you all tend to include or exclude tax when you decide on pricing your apps in the app store? Is there a community consensus on the etiquette here?

Is there a good way of fixing kotlinx.serialization's handling of nullable values? This class...

@Serializable
data class MyDataClass(
    val myProp: String?
)

... will throw

kotlinx.serialization.MissingFieldException: Field 'myProp' is required, but it was missing

if the json does not contain the

myProp

key. I really dont want to add a default value of

null

to every single optional field

Hi, im trying to program an android app for a school project. My idea is an app that contains exams and their corrections organized by subjects and with a pdf download option. Is that easy to do? Some help in how to start?

message has been deleted

is there a way to refer to

when

condition without binding it to a name? some sort of default provided name? For example in the code below, is it possible to write it without the

temp

variable?:

val temp = foo.bar.getBaz()
when (temp) {
is A -> print(temp)
is B -> ...
}

Currently using kotlin 1.4.10 in my android project. Is there an EAP or someway to try 1.4.20 early? I want to see if it fixes a compilation issue I'm having. I tried looking here https://kotlinlang.org/eap/ but only see a 1.4.0 rc.

How can I add all 3 lists of object into one? Given the first and the third one can be empty? There ain't something like listA.addAll(listB).addAll(listC) 🤔

kotlin-test's assertNotNull lets the compiler know that whatever is passed to it is not null afterwards, while junit's assertNotNull does not. Why is it like that?

one user is getting with one of out lib the following:

java.lang.LinkageError: loader constraint violation: when resolving method "imgui.ImGui.begin(Ljava/lang/String;Lkotlin/reflect/KMutableProperty0;I)Z" the class loader (instance of net/fabricmc/loader/launch/knot/KnotClassLoader) of the current class, net/aaa/bbbb/gui/screen/ModScreen, and the class loader (instance of sun/misc/Launcher$AppClassLoader) for the method's defining class, imgui/ImGui, have different Class objects for the type kotlin/reflect/KMutableProperty0 used in the signature

since he updated from 1.4.0 to 1.4.10, has anyone encountered something similar?

So I defined a property in

gradle.properties

file and got a reference in the

build.gradle.kts

file by declaring a global property:

val api_key: String by project

. I want to use

api_key

in my

Main.kt

, but I can't seem to figure out how to gain access. Searched on StackOverflow and all the results were android related. Can anyone help?

I am trying to get SAM conversion working. Why do I get errors right side of assignment in both

foo2

,

foo3

?

interface Foo {
    fun bar()
}

private val foo: Foo = object : Foo {
    override fun bar() {
        TODO("Not yet implemented")
    }
}

private val foo2: Foo = {}
private val foo3: Foo = Foo {}

where can I follow the progress of the IR backend? I wan't to know when it's scheduled to leave alpha

Hey guys! What are you using to measure code coverage? Jacoco doesn't have a very nice integration with Kotlin, marking inline functions as uncovered, for example, and others

Is there a way to add your own "prelude" that's automatically present in every file? For example, suppose you want to replace the standard library

map

with your own that returns an ImmutableList instead of a List. How would you do it?

Hi, I just started playing around with KMM today - I am having trouble running the ios simulator from Android studio. Is this the right place to ask for help?

It looks like #kmm exists as a channel but hasn’t gotten a whole lot of traction yet

Trying to use kotlinx immutable collections. As it says, I've added

implementation "org.jetbrains.kotlinx:kotlinx-collections-immutable-jvm:0.3.3"

to my gradle file, but it still can't seem to import. How should I debug this?

Hello! If I have a function that takes a callback that is called with a parameter, and for some callback I do not need or use this parameter – the only way to not get warnings about this is to use a @Suppress annotation, is this correct?

fun myCallback(@Suppress("UNUSED_PARAMETER") someValue: Int) { }

Is there a way in Kotlin, when I import something into a package, to make it so that it in turn becomes available for import from that package? e.g. say my package

foo

imports

bar.blub

, i want it to to be so that if somoene does

import foo.*

they also get blub.