What are your thoughts on committing the .idea file? Does this make sense or are those custom settings for every user?

I'm trying to write extension for AssertK that will deep compare objects ignoring id. Works well if I use

T:Any

but fails when I want to support nullable fields. Any idea how to cast other to not null type so I can access it class.members?

fun <T : Any?> assertk.Assert<T>.isEqualToIgnoringId(
    other: T
) {
    all {
        if (other == null)
            this.isEqualTo(null)
        else
            other?.let { it::class.members }
    }
}

I have a C++ library that builds with CMake and i am trying to write a GUI for it in kotlin and i am assuming i'll need to write JNI bindings for the library. i can't figure out how setup the build system for a project with C++ and kotlin/java for the JNI bindings. Any help would be appreciated.

hey I was wondering how I would disable warnings about using unsigned types? I know that they are experemental, I don't want to add @ExperimentalUnsignedTypes hundreds of times in my code. I've tried adding

tasks.withType<KotlinCompile> {
    kotlinOptions.jvmTarget = "1.8"
    kotlinOptions.freeCompilerArgs += "-Xexperimental=kotlin.ExperimentalUnsignedTypes"
}

this to my build.gradle.kts, but it still warns me in intellij

FIrst time I've seen this and I can't find info about it online. I can do the quick fix, but there has to be some reason it's not enabled by default, right?

Is there a way to only allow a single class

A

to instantiate a class

B

, while keeping

B

itself public? Basically I want

B

to have a private constructor that can also be accessed by

A

but not by a random class

C

. Putting

A

and

B

is the same file doesn't allow

A

to use the private constructor, and even making

B

a nested class of

A

also doesn't work. Is there a solution?

Hi , just wanted to understand what is the main difference between open and sealed class and also the use cases for its usage.

Is it possible to make a companion object equal to the output of some function? I am trying to do something like

companion object : SomeType = someFunc()

. Or do you always have to declare the companion, as in

companion object : SomeType {body}

?

One more question, would it be possible to override the equals and hashcode methods on the ByteArray from the Kotlin standard library, to check for value equality rather then referential equality? Extension methods seem to be shadowed by member declarations, but is there some other way of doing that or do I have to manually do this in all data classes that contain ByteArrays?

Hello everone 👋 - just starting out with kotlin and coming from mostly scripting languages I'm really enjoying it n.n

I don’t understand why this works: val UInt.le_ubytes:UByteArray get() { val quad = (0 until 31 step 8 ).map { shift -> (this shr shift and 0xFFu).ubyte } return quad.toUByteArray() } but this doesn’t work: val UInt.le_ubytes:UByteArray get() { val quad = (0 until 31 step 8 ).map { shift -> (this shr shift and 0xFFu).ubyte } return ubyteArrayOf(*quad) } It hates on the ubyteArrayOf() with the spread operator. It wants a UByteArray as the argument. Which is pointless, because why would I be using the ubyteArrayOf() helper if I had a UByteArray already?

To work with a Java API, I need to create a method whose return type is

Void

and has the following behavior:

override fun getResult(): Void {
        if (!success) throw RuntimeException()
    }

This doesn't compile, because a function with a block body requires a return statement.

Is there any channel to talk about kotlin development? I’m running the tests from https://github.com/JetBrains/kotlin/ in my computer and they don’t pass.

./gradlew ideaPluginTest

Simple way to have a closure execute 250.milliseconds in the future? Looking for the Kotroid equivalent of the Swiftios DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(250)) { Foo().makeABar() }

If I have

sealed class Foo<T:Any> {
	object Bar : Foo<Nothing>()
	class Baz(val p: String) : Foo<String>()

	// I can do this
	fun String.convert() = this.let(::Baz)
}

// One type argument expected for class Foo<T : Any>
fun String.convert2() = this.let(Foo::Baz)

typealias FooBaz = Foo.Baz

fun String.convert3() = this.let(::FooBaz)

I get an error if i try

Foo::Baz

but adding a type makes

Baz

an unresolved reference. The code does work if all generics are removed. Can I fix this without import statements?

If I have:

class Auto(val isNew: Boolean)
val car: Car? = Car(true)

why the following code works:

if (car?.isNew == true) println("new car")

and the following doesn't compile:

if (car?.isNew) println("new car")

This message was deleted.

When I have a chain of collection transformations, is it always possible to easily convert that to operations on a sequence? In other words: Is there any operation that I can use in a chain of collection operations, but not on a sequence?

Collections -> I have a SizedIterable list with dynamic content that came from an inner join statement. How can I map a new list with grouped "father" fields, and add an inner list with child records of each father?

I have an interface with a function that has the signature

fun <T: Any?> asArray(tClazz: Class<T>): Array<T>

, how ever, I have no idea how to return an Array of type T in Kotlin on a non-reified function with only the Class as argument.

Is there something similar to Java’s Stream.Builder? Something that I can pass around and let code add values to and finally create a Sequence? I mean I can always use a mutable list, but I like the smaller API of Stream.Builder.

when does Regex("1+2") (or "(1)+2" )fail to match "12" ?

I hate Java’s lack of unsigned values, particularly that “Byte” should have ever been signed. So I’m loving Kotlin’s Unsigned stuff, especially UByte(Array). Is there any reason NOT to embrace UByte(Array) throughout my app and just translate to/from at the edges when using Android APIs? For example, performance penalties? I notice that there doesn’t seem to be a UByteArrayInput/OutputStream, but I can probably make my own of those.

What do you use for mocking? Mockitos support for Kotlin is kinda meh, especially with coroutines and mockk seems kinda abandoned. There are lots of blockers and the author recently wrote that he has no time for mockk any longer.

Is there some trick to getting project wide Unsigned support? I tried:

is there a more kotlin idiomatic way of doing this?

for (i in 0..fooCount) {
            foos.add(bar.getFoo(i))
        }

I am using DynamDBMapper annotations on a data class (AWS Java SDK). I am trying to get back the methods that have a particular annotation, and I am getting nothing, even though annotations on the class itself are shown. Is there something that I am missing when retrieving method annotations? (see thread for details)

Folks, I am using KTOR/KOTLIN/NETTY and looking for monitoring tool like new relic or javamelody that support coroutines can you please help me with tool that finds hotspots in code/ and profiles time spent with GUI

I was just astonished to find out that Map.getValue(key) does not guarantee non-null value. If a map has explicit null value for a key, this method will return null !