I'm trying to implement a generic spy class to be used in tests for interfaces derived from a base UseCase interface... is there any way to make the spies generic? Or does one have to be made for each derived interface? (See thread for code)

Hello everyone, do you know if there is a way to implement a UI skeleton placeholder using Jetpack compose components or should it be done using a third party library?

Hi guys, I was wondering if there is a way to write a function similar to let, where I can set some context to the lambda invoked. More specifically, I want to write a method that takes as a parameter a lambda and gives some context (an object) available to that lambda. Example:

fun myFancyMethod(function: () -> O)

so that a caller can use it this way:

myfancyMethod{
  context.giveMeSomething() //context or it.context is available since it's set somehow from myFancyMethod
}

Is that feasible?

Has anyone noticed inconsistent behavior with

SomeClass::class.sealedSubclasses

method? Sometimes I need to

gradle clean

my project for it to return correct results. Happened with 1.4 and now with 1.5 RC versions

class SeonApi {
    companion object {
        fun getEmailScore(emailInput: String): String {
            return "hello"
            var request: HttpRequest = HttpRequest.newBuilder()
                .GET()
                .uri(URI.create("<https://api.seon.io/SeonRestService/email-api/v2.0/>".plus(emailInput)))
                .setHeader("X-API-KEY", @Value("\${seon_api_key}")) //***************complained: "Annotation class cannot be instantiated"
                .build()
            var response: HttpResponse<String> = HttpClient.newHttpClient().send(request, BodyHandlers.ofString())
            return response.body()
        }
    }
}

This piece of code failed to compile and the debug. Had been spending 30 minutes debuging + googling without any success, anyone has a suggestion?

Hi everyone, I'm trying to remove a duplication of this code:

.filter { _key, value ->
            value.getTimestamp().isBefore(Instant.now().plusSeconds(600))
        }

key

is a string but I don't care what type it is

value

can be multiple types but all implement the getTimestamp method that returns an instant, so I've tried tried to create a file like this:

interface DataWIthTimestamp {
    fun getTimestamp(): Instant
}

val filterFutureData: (key: Any, value: DataWIthTimestamp) -> Boolean = { _, value ->
    value.getTimestamp().isBefore(Instant.now().plusSeconds(600))
}

which doesn't work as it says

Type mismatch.
Required: Predicate<in String!, in Metric!>!
Found: (Any, DataWIthTimestamp) → Boolean

I know my implementation might not make sense 🙂

I noticed link is 404.

Hi I made a Kotlin project in Intellij. Kotlin files run just fine, however, when I create a java file I can't run it, giving me this error. Do I need to Edit Configurations for Java? I would assume you could run both..

So, I’m trying to make an honest effort to write code that doesn’t use exceptions to indicate expected (non-logic) errors, but I keep running into cases that exceptions solve very nicely and sealed classes do not. I’m finding it really hard to resist the urge to use exceptions, even though the fact that they’re unchecked means the type system doesn’t enforce error handling discipline on the caller. Examples of cases I don’t have good answers for: • Short-circuiting. I have to make a bunch of calls, the first of which that fails should stop execution of the rest. I’m not sure I see a good pattern for this with e.g. a Result type, other than wrapping each call with the same boilerplate to check the Result type and return early if appropriate. • Validation when instantiating a data class. Say I have a data class whose constructor does some validation on the passed-in values (say, one of its fields is an enum, but it’s being populated from an API call which returns a string). There’s no way that I can think of to signify failure in a constructor other than throwing an exception, since you can’t change the return type.

hello, no #ide specific channel?

I’m struggling understanding how to use in/out for generic types, here is what I’m trying to do :

interface Executor<T, U> {
    fun isExecutable(): (T) -> Boolean
    fun execute(): suspend (U) -> Unit
}

class MyClass<T, U> {

     val executors = mutableMapOf<String, Executor<T, U>>()

    fun register(eventName: String, executor: Executor<T, U>) {
        executors[eventName] = executor
    }

    inline fun <reified V : U> register(executor: Executor<T, V>) {
        val eventName = V::class.toString()
        register(eventName, executor)
    }
}

I get the following error from the IDE

Type mismatch. Required: Executor<T, U>, Found: Executor<T, V>

U

is a sealed class and

V

a subtype of that class. I did read the page about generic and “PECS” in the doc, but I still haven’t figured it out. Anyone knows what I need to change?

Hi. Is there a reason why 1.5.0 is not yet officially released, even though it seems available? At least our dependabot finds it and tries to update all our versions. Which is a bit confusing if you cannot find releasenotes 😅

API docs are still only 1.4?

I have an abstract class with two concrete subclasses containing implementations of

fun myFunction()

. The body of both implementations is different, but the last line is the same, calling a function in the abstract superclass. The common last line must be executed last. What is the most appropriate way to use Kotlin language features to refactor out the duplication?

Dumb question, just updated to kotlin 1.5 and I cannot find the declaration of “listOf”. What’s up? I couldn’t find anywhere telling that it changed so I can only guess this is not usual. Anyone?

What's the idiomatic way to map a nullable list? Let's say I have this class

class ProductModel {
   val productListModel: List<ProductListModel>? = null,
}

And I have the mapper like this

fun map(input : ProductModel) : List<Product>{
  return input.productListModel?.map{Product(....)}.orEmpty()
}

Is there another elegant way? If the list is null or empty I should return an empty List of Product and if not, the list mapped

does anybody know how to generate .d.ts typescript definitions from my jvm project data / value classes? I read about (https://kotlinlang.org/docs/js-to-kotlin-interop.html#jsexport-annotation) but don’t get it if it works from an jvm style kotlin project.

anyone having trouble with the new Duration API in 1.5?

Expression 'seconds' cannot be invoked as a function. The function 'invoke()' is not found

… literally looking at the seconds function in the Duration companion object 😳

does anybody know how to get the type (KType / KClass ?) of the embedded value in a value class?

if (klass.isValueClass) {
  // TODO get type of embedded value for further processing
}

update - I think I found it:

if (klass.isValue) {
  val ctor = klass.primaryConstructor ?: error("value class has no primary constructor")
  val valueType = ctor.parameters.firstOrNull()?.type ?: error("value class has no single parameter in constructor")
   // use it
}

If somebody knows a shorter way I would appreciate

Could be a better way of doing it without changing the signature of the model?

fun createDummyProduct(number: Int = 1) = Product(id = "id$number", name = "name$number", title = "title$number")

Every time I try to update the Kotlin plugin this happens...any ideas? I'm on IJ Ultimate 2021.1.1; the 'Plugins' settings area doesn't suggest any updates are available

does anybody know why https://pastebin.com/rdrdNDXn gives unresolved reference and https://pastebin.com/WSaThfvV doesn't and if it is possible to define a function within main(), why can't it be called too?

With 1.5 I can declare sealed subclasses outside of the parent class. With default sealed subclass I can access it easily by

Sealed.Subclass

, but is there a way to define new subclass in an other file but still be able to have it inside

Sealed

"namespace"?

class Sealed.NewSubclass: Sealed()

is not possible, but maybe there's an alternative? The reason why I need it is because I wanna generate some of sealed subclasses, and it's very convenient to have all subclasses under single namespace

When I try to update my kotlin plugin in intellij it tries to download 1.3.72 not 1.5.0, even though it was correct in the overview. Any idea what I can do? I use Intellij 2021.1.1

Hi ! I'm discovering the new Jetpack Compose for web. I discovered the ability to write Stylesheets in Kotlin. For non Kotlin supported properties, there is the property(propertyName: String, value: StylePropertyValue). I would like to be able to add a font family from ttf file to my style. I know there is the @font-face in css but how could I manage to use it with the property(...) thing ?

Hey, I have a question regarding bounds on generic types. ❓ In the Kotlin stdlib there this function:

@SinceKotlin("1.3")
@kotlin.internal.InlineOnly
public inline fun <C, R> C.ifEmpty(defaultValue: () -> R): R where C : CharSequence, C : R =
    if (isEmpty()) defaultValue() else this

You can call it and it works great. However, if I simply copy this function into my code (with intention to later have a slightly modified version), it simply does not compile:

public inline fun <C, R> C.ifEmpty2(defaultValue: () -> R): R where C : CharSequence, C : R =
    if (isEmpty()) defaultValue() else this

Produces error highlighting `CharSequence`:

Type parameter cannot have any other bounds if it's bounded by another type parameter

You can find the example here: https://pl.kotl.in/oGzbGuXah Why is this the case? Why can’t I use the same features used in stdlib?

Hi i want my dialog status bar like this as show in image. I asked in stack overflow also https://stackoverflow.com/questions/67415478/how-to-make-status-bar-inactive-in-custom-dialog

I created this issue here - https://youtrack.jetbrains.com/issue/KT-46508 but thought might get better guidance here. Consider main.kt and Attachment.java below, should the compiler have warned about self-assignment in extension method below?

private fun ImageFile.toJavaAttachment(): JavaAttachment {
    return JavaAttachment().apply {
        /* Here imageName is correctly referenced */
        fileName = imageName
        /* compiler should have warned that this is a self-assignment? */
        updateTime = updateTime
    }
}

package org.kotllinlang.play

import JavaAttachment

data class ImageFile (
    val imageName: String,
    val imageType: Int,
    val updateTime: String
)

data class KotlinAttachment (
    var fileName: String = "default-kotlin-file-name",
    var updateTime: String = "default-kotlin-time"
)

fun main() {

    val image = ImageFile(
        imageName = "file.jpg",
        imageType = 1,
        updateTime = "this-is-updated-time-stamp")

    val javaAttachment = image.toJavaAttachment()

    val kotlinAttachment = image.toKotlinAttachment()


    println("Java attachment $javaAttachment")

    println("Kotlin attachment $kotlinAttachment")

}

private fun ImageFile.toKotlinAttachment(): KotlinAttachment {
    return KotlinAttachment().apply {
        fileName = imageName
        /* compiler correctly generates a self-assignment warning */
        updateTime = updateTime
    }
}

private fun ImageFile.toJavaAttachment(): JavaAttachment {
    return JavaAttachment().apply {
        /* Here imageName is correctly referenced */
        fileName = imageName
        /* compiler should have warned that this is a self-assignment? */
        updateTime = updateTime
    }
}

package org.kotllinlang.play;
public class JavaAttachment {

    public String getFileName() {
        return fileName;
    }

    public void setFileName(String fileName) {
        this.fileName = fileName;
    }

    public String getUpdateTime() {
        return updateTime;
    }

    public void setUpdateTime(String updateTime) {
        this.updateTime = updateTime;
    }

    private String fileName;
    private String updateTime;

    public JavaAttachment() {
        updateTime = "default-java-time";
        fileName = "default-java-file-name";
    }

    @Override
    public String toString() {
        return "JavaAttachment{" +
                "fileName='" + fileName + '\'' +
                ", updateTime='" + updateTime + '\'' +
                '}';
    }
}

Anyone met problems when upgrading

org.jetbrains.kotlin.jvm

 to 

1.5.0

with subproject dependency?

An exception occurred applying plugin request [id: 'org.jetbrains.kotlin.jvm', version: '1.5.0']
> Failed to apply plugin 'org.jetbrains.kotlin.jvm'.
   > Gradle#projectsEvaluated(Action) on build 'boot' cannot be executed in the current context.

I am using build.gradle.kts, It works fine with kotlin 1.4.31, but not 1.5.0.

hi, just wanted to ask a quick question regarding multiple elvis operators. TLDR: is this correct?

id = action.id ?: state.activeId ?: -1