kotlinlang #kotlin-native

I am kind of stuck on iOS packaging options and am looking for some help. The goal is to build static frameworks that can be published with cocoapods, but also possibly other options in the future. I've tried the following configurations (a thread):

v79

11/02/2020, 6:20 PM

With a huge amount of thanks to @Marcin Wisniowski and @Big Chungus I've got a Kotlin Native application running on the Pi, using a Linux shared library. And that's cross-compiled from Windows X86 to Linux ARM32Hfp for my Raspberry Pi. And the mistake I had made? Windows can't follow a linux symbolic link, so it wasn't finding

libcurl.so

because the true library file was

libcurl.so.4.5.0

- just a naming problem.

🎉 3

Leon K

11/02/2020, 11:51 PM

Hey folks! We're trying to see if we can write a Window manager with Kotlin/Native, but starting out with it, we're hitting some issues we cannot seem to figure out. this is working c code:

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xcb_connection = create_xcb_connection();
xcb_setup = xcb_get_setup(xcb_connection);
xcb_screen_iterator = xcb_setup_roots_iterator(xcb_setup);
xcb_screen = xcb_screen_iterator.data;
xcb_root = xcb_screen->root;

and this is the kotlin counterpart to the c code above, but it unfortunately crashes with a null-pointer,

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import kotlinx.cinterop.*
import xcb.*

fun main() {
    val connection = xcb_connect(null, null)
    val xcb_setup = xcb_get_setup(connection)!!
    val xcb_screen_iterator = xcb_setup_roots_iterator(xcb_setup)

    // val xcb_screen = xcb_screen_iterator.placeTo(scope).pointed.data!!

    // This !! crashes, indicating that the data value here is null. in the equivalent C code shown above, 
    // This exact same value is _not_ null however, which makes us think
    // that we are wrongly using the Kotlin/Native C interop somehow.
    val xcb_screen = xcb_screen_iterator.useContents { data }!!

    val xcb_root = xcb_screen.pointed.root
    
    println("okidoki")
}

As described in the comment, we're getting a null value on

xcb_screen_iterator.useContents { data }

, which - as far as we understand - should be equivalent to the C code given above, which does work. Any help would be appreciated. LIkely, we're just failing to understand how to use kotlin native's C interop

Arnaud Vallat

11/03/2020, 12:17 AM

Hi, I'm building a library in Kotlin Multiplatform and Kotlin Native that targets different platform including linuxArm32Hfp. The code I have on the linux side that interacts with the shared kotlin library code is in C++. Is there a way to change the projection to C++ instead of C? I found it extremely verbose to allocate objects and call their methods. I couldn't find something in the documentation about that, so curious. Thank you

Elias

11/04/2020, 11:55 AM

Hi there. I have been looking at compiling a native project for linux arm32 v7 but are struggling to get my binary to run. I have attempted to compile down to linuxArm32Hfp. The code is for now an simple auto generated Hello World program that runs fine on my computer when compiled to mac. This is configured in a build.gradle.kts file. If it needs to be done elsewhere to get more control that should note be an issue. The unit in question has the following processor and linux version, in case I have misconstrued what the target is. • Linux version 3.12.10+ (root@localhost) (gcc version 4.9.3 (GCC) ) #1 custom • Model name: ARMv7 Processor rev 2 (v7l) • Features : swp half fastmult vfp edsp neon vfpv3 tls vfpd32 We are currently running a golang binary on the unit, that is compiled with the following parameters. • GOOS=linux GOARCH=arm GOARM=7 Thanks in advance for any help!

phisch

11/04/2020, 2:43 PM

How do you guys test your kotlin native code (ideally multiplatform). Do you just add another target jvm to get junit integration in IDEA, or how is your workflow? I have no idea how to set this up properly to be able to generate test from within IDEA etc.

Arnaud Vallat

11/04/2020, 5:01 PM

Hi, is there a way to have data classes being projected better as a C struct without a function pointer for each member to access its data?

➕ 1

🤔 1

Vinod Rai

11/05/2020, 8:53 AM

Hey! I am getting while compileKotlinIos. Can anyone pls tell me how to rectify this issue I am not available to get the root cause earlier it was working fine.

2020-11-05T14:06:50.543+0530 [ERROR] [system.err] e: Compilation failed: null

* Compiler version info: Konan: 1.4.10 / Kotlin: 1.4.10

2020-11-05T14:06:50.543+0530 [ERROR] [system.err]  * Output kind: LIBRARY

2020-11-05T14:06:50.543+0530 [ERROR] [system.err]

2020-11-05T14:06:50.544+0530 [ERROR] [system.err] e: java.lang.StackOverflowError

2020-11-05T14:06:50.544+0530 [ERROR] [system.err] 	at org.jetbrains.kotlin.psi2ir.generators.IrSyntheticDeclarationGenerator.visitCall(IrSyntheticDeclarationGenerator.kt:17)

2020-11-05T14:06:50.544+0530 [ERROR] [system.err] 	at org.jetbrains.kotlin.ir.expressions.impl.IrCallImpl.accept(IrCallImpl.kt:78)

2020-11-05T14:06:50.544+0530 [ERROR] [system.err] 	at org.jetbrains.kotlin.ir.expressions.impl.IrMemberAccessExpressionBase.acceptChildren(IrMemberAccessExpressionBase.kt:57)

2020-11-05T14:06:50.544+0530 [ERROR] [system.err] 	at org.jetbrains.kotlin.ir.expressions.impl.IrCallWithIndexedArgumentsBase.acceptChildren(IrCallWithIndexedArgumentsBase.kt:63)

2020-11-05T14:06:50.544+0530 [ERROR] [system.err] 	at org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoidKt.acceptChildrenVoid(IrElementVisitorVoid.kt:275)

william

11/06/2020, 12:08 AM

can anyone help me understand how atomicfu library works? what does it do under the hood that allows you to mutate something wrapped with

atomic(...)

? i understand that the object in

atomic

is frozen, but its unclear to me why it can be mutated. (also what does

fu

stand for / mean?)

Jamie Craane

11/06/2020, 8:54 AM

I have some problems setting up a dependency in a KMM project from a jvmmodule to the shared code. In short, the attached image shows what I want to do. The jvmmodule has a class called Test with a main method which uses code from the shared module. I tried several solutions, none which are 100% working: 1. (https://github.com/jcraane/kmm-with-jvmmodule/tree/jvm-kotlin-lib) jvmmodule is configured as a regular kotlin jvm module which also has the application plugin enabled for testing purposes. The module has a project dependency on the shared module. When the Test class is ran using the ./gradlew jvmmodulerun command everything works as expected. The output in the console should be ‘Hello from JVM’. In IntelliJ or Android Studio the Greeting class in Test.kt cannot be found (not in the editor, compile error) and not at runtime. When running the classes from the gutter icon the following error occurs:

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Caused by: java.lang.ClassNotFoundException: Greeting
   at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:602)
   at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
   at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
   ... 1 more

2. (https://github.com/jcraane/kmm-with-jvmmodule/tree/jvm-mp-lib) (inspired by kotlinconf app) jvmmodule is configured as a multiplatform module with a single jvm target and a project dependency on the shared module. In this scenario code completion works in IntelliJ but when the Test class is run from the gutter icon the following error occurs:

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Error: Could not find or load main class TestKt
Caused by: java.lang.ClassNotFoundException: TestKt

Is this the correct way of using shared code from a plain kotlin (kvm) module?

v79

11/07/2020, 8:58 AM

I'm having trouble using a cinteropt enum in my Kotlin code. Given the following C header:

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typedef enum
{
    BCM2835_GPIO_FSEL_INPT  = 0x00,
...
} bcm2835FunctionSelect;

I have added this as a strictEnum to `libbcm.def`:

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strictEnums = bcm2835FunctionSelect

Then when I try to use it in Kotlin code, there are two issues. Firstly, I have to use it rather verbosely:

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bcm2835_gpio_fsel(pin, bcm2835FunctionSelect.BCM2835_GPIO_FSEL_INPT.value.toUByte());

And secondly it doesn't compile, with the following error:

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e: kotlin.UninitializedPropertyAccessException: Parent not initialized: org.jetbrains.kotlin.ir.declarations.impl.IrEnumEntryImpl@31d85176
        at org.jetbrains.kotlin.ir.declarations.impl.IrDeclarationBase.getParent(IrDeclarationBase.kt:39)
        at org.jetbrains.kotlin.ir.util.IrUtilsKt.getParentAsClass(IrUtils.kt:286)
        at org.jetbrains.kotlin.backend.konan.ir.interop.cenum.CEnumCompanionGenerator.generateAliasGetterBody(CEnumCompanionGenerator.kt:84)

It looks like I've found a bug, but maybe I'm doing something wrong?

tieskedh

11/08/2020, 5:42 PM

Hello everyone, I'm very new to Kotlin native and I know almost nothing about iOS-development. I'm trying refactor an existing IOS-app which uses pods. I use JWTDecode as POD dependency. The idea autocompletion etc. works. When I build the code for an emulator, it fails on JWTDecodeIos. The error I get is:

(1,9) Module JWTDecode not found.

The project has objc-attributes added: https://github.com/auth0/JWTDecode.swift/pull/55 The top-level pod uses:

use_frameworks!

(It also has the JWTDecode-dependency...) I do have:

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// Revert to just ios() when gradle plugin can properly resolve it
val onPhone = System.getenv("SDK_NAME")?.startsWith("iphoneos") ?: false
if (onPhone) {
    iosArm64("ios")
} else {
    iosX64("ios")
}

which maybe explains the difference? But removing the if and trying first one and then the other also didn't seem to work. Can anyone help me?

Nikky

11/10/2020, 12:31 AM

if i recall correctly one could have a shared sourcset for all native targets, how can i configure that ?

KamilH

11/10/2020, 1:14 PM

In my multiplatform project I created a simple structure to implement DI manually, main part of it are

Provider<T>

interface and

Singleton<T>

abstract class (code in thread). It works very well, however when I’m testing it on iOS I’m keep getting Uncaught Kotlin exception: kotlin.native.concurrent.InvalidMutabilityException: mutation attempt of frozen
when trying to

get()

Singleton

. How can I fix it without using

object

and

ThreadLocal

max.cruz

11/11/2020, 1:18 AM

Hi. I’m updating an Android/iOS multiplatform project to 1.4, but I’m having a hard time understanding the changes in coroutines and concurrency. Running a code like this:

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val scope = CoroutineScope(Dispatchers.Main + SupervisorJob())
...
scope.launch {
	val something = withContext(Dispatchers.Default) { suspendCall() }
	println(something)
}

Works fine in Andorid but in iOS I get:

Uncaught Kotlin exception: kotlin.native.IncorrectDereferenceException: illegal attempt to access non-shared <object>@3faca88 from other thread

Daniel Gruber

11/13/2020, 9:38 AM

Hi there :) we‘re currently developing a Kotlin native app for Windows and want to use Coroutines. As it seems we need to add some kind of Runloop with yield in order to keep them running, does someone know a better idea? Thanks a lot!

v79

11/13/2020, 3:19 PM

Linking in Kotlin native is the big, slow part, isn't it? I tried a gradle build on my Raspberry Pi, and Gradle wanted 3Gb of RAM to do the linking! Back on my Win PC, I've got a single large Kotlin enum with a bytestream (about 83kb) and linking my otherwise small project now takes about 2 or 3 minutes 😞.

🤞 2

Vaclav Hodek

11/14/2020, 12:54 PM

Does anyone have a problem running a native app built with Kotlin for macOS on Big Sur? It works great on all other macOS versions except for Big Sur. Right after the launch, the app is closed with seg fault.

👀 1

SBNTT

11/16/2020, 12:03 AM

I tried to publish a mpp library using the 1.4.20-RC kotlin version No metadata module was published, so consumer project doesn't have autocomplete in common module How do i bring back the metadata module ?

Alexander Black

11/17/2020, 6:57 PM

Hello all, I’m trying to write a file download method using Ktor on a native/mpp app. I hope this is the place to ask this… if not please direct me to the right channel. here’s my method so far:

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suspend fun HttpClient.downloadFile(
    output: File,
    downloadUrl: Url,
    md5Hash: String
): Flow<DownloadResult> {
    return flow {
        try {
            val response = get<HttpResponse> { url(downloadUrl) }
            val data = ByteArray(response.contentLength()?.toInt() ?: 0)
            var offset = 0
            do {
                val progress = (offset.toDouble() / data.size) * 100
                emit(DownloadResult.Progress(progress))
                val currentRead = response.content.readAvailable(data, offset, data.size)
                offset += currentRead
            } while (currentRead > 0)

            if (response.status.isSuccess()) {
                if (data.md5().hex == md5Hash) {
                    output.write(data)
                    emit(DownloadResult.Success)
                } else {
                    emit(DownloadResult.ErrorCorruptFile)
                }
            } else {
                emit(DownloadResult.ErrorBadResponseCode(response.status.value))
            }
        } catch (e: TimeoutCancellationException) {
            emit(DownloadResult.ErrorRequestTimeout("Connection timed out", e))
        } catch (t: Throwable) {
            emit(DownloadResult.Error("Failed to connect", t))
        }
    }
}

The problem is that the

response.content.readAvailable()

method always seems to read the whole file at once without chunking it up, which means my progress emission only gets outputted once. I’m wondering if there’s something I’m doing wrong here? or if that’s normal behaviour? Also as a side note the file I’m testing on is 25MB so it should emit a few times I’d think.

Alexander Black

11/18/2020, 5:26 PM

I’m trying to build a simple objective c library from it’s original source and generate bindings for it... I got the bindings to build, but when I try to build my app on the iOS simulator I get this message:

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Undefined symbols for architecture x86_64:
  "_OBJC_CLASS_$_Reachability", referenced from:
      objc-class-ref in result.o
ld: symbol(s) not found for architecture x86_64

I’m thinking it has something to do with building from a .m and .h file and it not being a dynamic library, so the binaries are not included, but I’m not sure how to include them here’s my def in my build.gradle.kts:

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iosX64("ios") {
            compilations.getByName("main") {
                val reachabilityInterop by cinterops.creating {
                    defFile(project.file("src/nativeInterop/Reachability.def"))
                    val headerPath = project.file("src/nativeInterop/Reachability/").absoluteFile
                    compilerOpts("-I${headerPath}", "-L${headerPath}")
                }
            }
        }

v79

11/19/2020, 7:25 AM

Well, adding one 40-line kotlin file, and one 4kb C-library, increased compilation times of this project https://github.com/v79/WaveShareTests/tree/libbmp from about 3.5minutes to 1 hour 40 minutes.

👀 2

aleksey.tomin

11/20/2020, 10:28 AM

I make macOS application. For some reason (maybe coroutines bug) I’ve replace _`app.run()` (_app = NSApplication.sharedApplication) to

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app.finishLaunching()
while (active.value) {
    app.nextEventMatchingMask(NSEventMaskAny, null, NSDefaultRunLoopMode, true)?.let {
        app.sendEvent(it)
    }
    runBlocking {
        delay(100.milliseconds)
    }
}

But now hotkeys (cmd+Q) and window’s button

close

don’t work. How can I process this events manually in macOS code? In main cycle? In Controller? In some

NSWindow

field?

Animesh Sahu

11/20/2020, 5:07 PM

Will K/N support C++ interop in future (not soon but some day)?

👀 3

benny.huo

11/23/2020, 8:05 AM

How to compile a shared library on Linux? I tried but got a ld error.

dambakk

11/23/2020, 8:47 AM

Hi! We use our common module for communicating with an API and, as everyone else, use a sealed class for the response:

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sealed class Response<out T : Any> {
    data class Success<out T : Any>(val data: T) : Response<T>()
    data class Error(val reason: ErrorReason) : Response<Nothing>()
}

Receiving success in ios is ok. However, we are not able to cast the result to an

Response.Error

. When printing the object to console (

(lldb) e dump(response)

) we can see that it is an

Optional(Error)

object with all the params we are looking for, but we cannot cast it to en Error in any way. Anyone knows what we have to do?

Alex Gladkov

11/23/2020, 11:50 AM

Hello, everyone. Has anyone worked with Keychain in Kotlin Native? We need to read from keychain from iosMain. I've seen Kissme library, but we can't use it

Michal Klimczak

11/23/2020, 12:25 PM

I'm completely new to kotlin-native. Trying to use it for multiplatform mobile and when I set up

ktor

I get an error (i have narrowed it down to an issue with initializing ktor

serializer)

. Not specifically asking about the serializer issue right now, but tell me - is this how the error reports are supposed to look (local build, local simulator), or do I need to somehow symbolicate the debug builds as well? It seems that everyone talks about symbolication of kotlin-native reports in crashlytics in release builds, no one mentions how it works during development.

Oleg Yukhnevich

11/23/2020, 1:18 PM

Hey, does anyone tried to profile K/N using some interactive tool like IDEA async profiler for JVM? So I need, not to benchmark, but find places, which are consuming CPU. I know, CLion has profiler, may be it's possible to somehow attach it to executable produce by K/N compiler?

steelahhh

11/24/2020, 2:48 PM

Hi, I'm getting

Symbol with IrSimpleFunctionSymbolImpl is unbound

when running

linkDebugFrameworkIos(Arm64, X64)

After some investigation, it turned out that the piece of code causing this exception is this:

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lateinit var property: String
    private set

Without

private set

it builds just fine. Is it a known issue?