hey! Is there any way when using

awaitAll()

with different variables of different types for it to not be casted as Any?

Hello! I have a question but I was not sure which was the appropriate channel to post it. I have a multi-module project and I noticed that in some modules I can not use the

buildList

,

buildMap

, etc. due to

Unresolved reference

. In my gradle file I have added a stdlib dependency. So why does this happen? Does it need some extra configuration?

hello, does anyone know a good test coverage gradle plugin for kotlin?

In the case of a maven project with Kotlin and Java side by side, the Kotlin docu (https://kotlinlang.org/docs/maven.html#compile-kotlin-and-java-sources) suggests this configuration

<configuration>
    <sourceDirs>
        <sourceDir>${project.basedir}/src/main/kotlin</sourceDir>
        <sourceDir>${project.basedir}/src/main/java</sourceDir>
    </sourceDirs>
</configuration>

but what do I do if I have a multi-module project?

${project.basedir}/src/main/kotlin

lacks the module in it's path, doesn't it?

am i correct in thinking this is a false positive inspection on my mvn pom? updates says i am running plugin version 221-1.7.0-release-281-IJ5591.52

Kotlin version that is used for building with Maven (1.7.0) differs from the one bundled into the IDE plugin (1.6.10)

is there a feature in between it being a 'data' class and a normal class? how do i get kotlin to generate componentN's if it is not a data class?

Hello! Can anyone tell me how to use posgtresql with jetbrains exposed as want to build a basic blog app using micronaut framework.

I have a huge file to read, more than 5GB. I need to do some transformation over each line, convert into my data object and than persist.

File.forEachLine

is a good choice for that?

Hello there... I'm new here and I very interested in learning about kotling... I'm curretly working with Salesforce and I wanted to create POC to integrate Salesforce with external systems using serveless APIs...

does anyone know if

b in a..c

has the same performance as

a <= b && b <= c

?

Is there any way to force a failure in the

runCatching

block like:

runCatching {
     when (some_condition) {
         1 > failure
         else -> todo
}

Is there any way to get a "safe"

is

check on Kotlin/JVM, in the sense that it doesn't fail with

NoClassDefFoundError

if the class is not on the classpath? I would like to do something with an object if it's of a given type, with the smart cast, but I don't want it to fail if running on lower JDK that doesn't have that class, I just want the condition to be false, and the code to move on without trying to load the class.

hello, jacoco says that this specific line has 6 branches. i can't figure out the missing branch, does anyone know?

Is there a way to prevent developers from using kotlin-logging's logger.log("this $expensiveOperation()"), in favor of them doing logger.log { "this $expensiveOperation()" } ? https://github.com/MicroUtils/kotlin-logging

Hello, The attached file contains a class that tests access to a block of code protected by a mutex. The pattern is I only want the first coroutine to access the protected block, by rerouting all subsequent calls using a condition on mutex.isLocked. I’m getting inconsistent behavior: at times all coroutines can access the block and at other times, they get rerouted. With some experimentation, if I delay launching coroutines, then the expected behavior is observed, however, this is not a practical solution. Is there a best practice around using Mutex? Thanks!

import kotlinx.coroutines.*
import kotlinx.coroutines.Dispatchers.Default
import kotlinx.coroutines.sync.Mutex
import kotlinx.coroutines.sync.withLock

class TestMutex {
    val mutex = Mutex()

    suspend fun createJobs() {
        val job1 = CoroutineScope(Default).launch {
            println("Job1")
            acquireMutex("Job1")
        }

        val job2 = CoroutineScope(Default).launch {
            println("Job2")
            acquireMutex("Job2")
        }

        val job3 = CoroutineScope(Default).launch {
            println("Job3")
            acquireMutex("Job3")
        }

        joinAll(job1, job2, job3)
        println("Delaying for a bit...")
        delay(1000)
        println("Done")
    }

    suspend fun createJobs2() {
        CoroutineScope(Default).launch {
            repeat(3) {
                CoroutineScope(Default).launch {
                    println("Job$it")
                    acquireMutex("Job$it")
                }
            }
        }.join()

        println("Delaying for a bit...")
        delay(1000)
        println("Done")
    }

    suspend fun acquireMutex(id : String) {
        if (!mutex.isLocked) {
            mutex.withLock {
                println("Got here...$id")
            }
        }
        else {
            println("I was directed to here...$id")
        }
    }
}

suspend fun main() {
    val testClass = TestMutex()

    println("First run...")
    testClass.createJobs()

    println("Second run...")
    testClass.createJobs2()
}

given some constraints, I have to express some logic via boxed primitives It turns out I also have to collect them in a map, but different boxed instance of the same value (ie

java.lang.Boolean(true)

, which returns a boxed Boolean) won't be seen as different keys, that is they would be overwritten how can I solve it?

Is there a way to link two field states together?

class FormField {
    var hasError: Boolean by mutableStateOf(false)
    var errorMessage: String? by mutableStateOf(null)

    // errorMessage != null iff. hasError == true
}

I tried contracts but one cannot reference variables that are not part of the contract method. I can't reason about

this@FormField.errorMessage

inside the implies boolean expression.

Hi, Is there any guidelines when to use sequences vs normal collection operations with some dataset? Is there overhead if sequence is used with small dataset?

Is there a Kotlin convenience function that allows me to combine multiple Iterables into a single Iterable? In other words, can I do something like this:

(list1 + list2).firstOrNull { it.matches(something) }

but without eagerly iterating the lists and creating a new list from them? In other words, exactly like Guava's

FluentIterable.concat(list1, list2)

but more Kotlin-idiomatic?

Question about use of lateinit var: I’ve only seen it used in class variables, but I recently came across it in a PR from someone new to Kotlin that used it inside a method call. What are the patterns and advice for using lateinit var inside methods? Or should it be avoided? Is the below use of lateinit valid?

fun degreesToDirection(degrees: Float?): Direction {
            var smallestDistance: Float = Float.POSITIVE_INFINITY
            lateinit var direction: Direction

            degreesMapping.entries.forEach {
                if (abs(it.value - (degrees ?: 0f)) < smallestDistance) {
                    direction = it.key
                    smallestDistance = (degrees ?: 0f) -  it.value

                }
            }

            return direction
        }

Possibly an IntelliJ question, is there a way to specify the root package name? I noticed if I have at least 1 class in the root and set the package to the name I want, then new files added there or sub directories automatically get the correct package name. Problem is if there are no classes in the root (only other sub-packages) then new files created in those don't get the correct package name and defaults to "package dirname" instead of "com.blah.modulename.dirname"

Is it possible to have nested lambdas which uses different

DslMarker

markers and picking the nested one? If I have two function with the same name, the outermost is used

kotlin {
    android() // from kotlin
    multiplatform {
        common()
        android() // from kotlin, should be from multiplatform
        jvm()
    }
}

is it possible to use ktor's type-safe requests to call an endpoint that needs a query param with no argument. I tried doing this:

@Serializable
@Resource("/end_point")
class EndPoint(val query: String? = "")

client().get(EndPoint())

This results in:

<http://base_url/end_point?query=>

but I just want it to be

<http://base_url/end_point?query>

Does val property has a setter or not ? And is it equivalent to var property having private setter? E.g. 'val a = 2' is same as 'var a = 2 private set'

My project builds successfully in Kotlin 1.6.21. When upgrading to Kotlin 1.7.0 I get:

[error] Compliance level '1.4' is incompatible with target level '11'. A compliance level '11' or better is required.

It 's a simple gradle kotlin("jvm") project with:

java {
    sourceCompatibility = JavaVersion.VERSION_11
    targetCompatibility = JavaVersion.VERSION_11
}

tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile> {
    kotlinOptions.jvmTarget = "11"
}

I have no idea what Compliance level is

Hello all. I'm trying to understand why it's giving error, and how to fix it

abstract class SomeClass {

abstract fun someFunction(someParameter: String) : List<String?>

}

suspend inline fun <reified T : SomeClass> otherFunction(): Return<T> {

val someAtt = T::someFunction("abc")

}

error: 
left-hand side of callable referece cannot be a type parameter

I'm mighty confused. I've got a Kotlin 1.7 project, requiring JDK 18. It doesn't compile:

e: D:\Development\Experiments\Pellet\server\src\main\kotlin\dev\pellet\server\PelletServerClient.kt: (8, 17): Unresolved reference: UnixDomainSocketAddress

IntelliJ can see the import (no red squiggly lines). In Project Structure, I've chosen SDK `openjdk-18 java version "18.0.1"`(and I've also tried the cornetto variant of JDK18). The language level is set to 17 in InteilliJ and in the

build.gradle.kts

file. In IntelliJ's External Libraries view I can drill down to

<http://java.base.java.net|java.base.java.net>

and see the

UnixDomainSocketAddress

class (it was introduced in Java 16). But neither IntelliJ nor Gradle can find the class to compile it! (I've even dug into the JDK source folder, and it definitely exists!). Please, any ideas?

Is there any way to store reified types to a variable?

so I am trying to add a list of items to a list, there’s 1 item that I would like to either add (or not add) according to some flag

Has anyone been having issues using sealed classes/interfaces in Kotlin 1.7? I seem to constantly get runtime issues with classes throwing exceptions saying things like "X can't extend sealed class" when it has worked fine before. Plus compile-time issues where exhaustive when statements will break, saying they need an else when they definitely don't. They get fixed by doing completely clean builds so I was wondering if maybe there's an issue with compilation? I'm using the incremental kotlin compiler with classpath snapshots - could this be an issue with that?