Does anyone have tips for improving iterative/debug KMP/iOS workflows without having a monorepo setup? Current setup: We currently have separate repos for our shared libraries and iOS app (

quizlet-kmp

and

quizlet-ios

). Our current approach is that `quizlet-kmp`'s CI builds the framework and publishes it to our private spec repo. iOS folks can then just pull the latest version. Problem: This approach has worked fine for us for the past while, but some issues with this approach that are starting to get annoying are: 1. It takes a lot of time to iterate within KMP and test the change on iOS. Having to push, wait for a release to be published, update your podfile, etc is time consuming. We want an opt-in way to allow iOS folks to develop using locally checked out KMP sources. 2. We can't drop breakpoints into the KMP code to debug issues on iOS. My understanding is that this is impossible to do unless you've built the code locally. What we're thinking: 1. The official Kotlin/Native Cocoapods Plugin seems to address issue 1 if we use it in an opt-in way (defaulting to CI builds instead). 2. Touchlab's xcode-kotlin plugin for Xcode seems to address issue 2 if the framework is built locally (and I think it's designed to be used alongside the cocoapods plugin?) Both of the examples for these tools are using a monorepo setup though. Has anyone gotten them working with separate, independent repos? I think I should be able to get the cocoapods plugin working by pointing the ios app's

Podfile

to the absolute path of `quizlet-kmp`'s generated Podspec (regardless of directory). This could be conditionally done for every iOS engineer, since the Podfile is just a ruby script. I also think the xcode-kotlin plugin should also allow me to drag in files from any arbitrary directory. I'd love to hear if anyone else has done so and can confirm!

Is it possible to catch exceptions thrown by Swift/Objective-C code? I’m integrating a library whose methods are throwing various exceptions (

NSException

) and I would like to catch and handle them, is it possible? I can see that the documentation mentions that it’s not yet possible, but maybe some work has been done in this topic? Is there any issue I can star and follow?

Note that the opposite reversed translation is not implemented yet: Swift/Objective-C error-throwing methods aren’t imported to Kotlin as exception-throwing.

How do I turn a string into a

CPointer<ByteVar>

? I only see

.cstr

documented but that turns it into a

CValues<ByteVar>

strangely enough it crashes either in my function or before it depending on what functions I have defined somehow?

I believe I've seen several repos (include JetBrains' own) using JNI to write functions that get used in both JVM apps, and in Kotlin Native. If true, how does this work? Since JNI requires the

JNIEnv*

param implicit in all calls. Or am I out of my mind haha

Not sure how KN is transparently calling

Java_org_jetbrains_skija_Canvas__1nDrawPicture

without (what looks like) passing any

JNIEnv

🤔

Yo I'm trying to get the target of a symlink in posix. I'm trying

realpath

(platform.posix.realpath) but for some reason, a

private

prefix is added on the resolved path. Any idea why that could be? Code is something like that

val fullpath = realpath(path.toString(), null)
        try {
          symlinkTarget = Buffer().writeNullTerminated(fullpath).toPath()
        } finally {
          free(fullpath)
        }

And my test fails with

kotlin.AssertionError: Expected </base/symlink-target>, actual </private/base/symlink-target>.

How does one adds parameters to a native call? Like there is

fun realpath(arg0: String?, arg1: CValuesRef<stat>?): Int

In the console, there are multiple params like

--logical

,

--zero

, etc. How do we set those up when calling from Kotlin native?

Has anyone have experience with what causes a

SIGSEGV: Attempted to dereference garbage pointer 0xe480162a0.

? Total iOS noob here, but any suggestions could help

What is the reason that

dispatcher

gets frozen after launching the job? I noticed it does not happen when

channel

is a global value. I’m having issues wrapping my head around it.

class FreezeTest {
  private val dispatcher = ImmediateDispatcher()
  private val callbacks = AtomicReference(emptyList<() -> Unit>().freeze())

  @Test
  fun freezeTest() = runBlocking(dispatcher) {
    println("1 isFrozen: ${dispatcher.isFrozen}") // False
    val job = launch {
      val channel = Channel<Unit>()
      val callback: () -> Unit = { channel.trySend(Unit) }
      callbacks.update { it + callback }
      try {
        for (signal in channel) {
          channel.send(Unit)
        }
      } finally {
        callbacks.update { it - callback }
      }
    }
    println("2 isFrozen: ${dispatcher.isFrozen}") // True
    job.cancel()
  }
}

fun <T> AtomicReference<T>.update(func: (T) -> T) {
  while (true) {
    val old = value
    val new = func(old).freeze()
    if (compareAndSet(old, new)) break
  }
}

class ImmediateDispatcher : CoroutineDispatcher() {
  override fun dispatch(context: CoroutineContext, block: Runnable) = block.run()
}

Could anyone explain why I get frozen collection mutation in this code? It is marked as ThreadLocal.

Where can I find an example of allocating an array of structs in order to pass a

CValuesRef

to the leading item + item count to a C function? I've done with things like ByteArray where I can call

refTo(0)

but I don't see an explanation or example of how to do this with a struct type.

Is there any reason why instead of only being able to generate definitions from

C .h -> Kotlin Native type

you could write a compiler plugin that did codegen and emitted an

.h

?

interface SomeStruct {
    @CType.Int32
    val anInt: Int
}

typedef struct SomeStruct {
  int32_t anInt;
} SomeStruct;

Hi, I wanna try making some stuff with Kotlin/Native for the Wasm target, and I saw that IDEA doesn't have good support for kotlin native. What should I use? (I have access to the all-products pack)

I'm trying to add a dependency on a CocoaPod with custom cinterop options, as described here. I want cinterop to pass "-fmodules" and "-fcxx-modules" to the compiler, and so I'm using the following bit inside the cocoapods block of my build.gradle.kts file:

pod("MatrixSDK"){
            extraOpts = listOf("-compiler-options = -fmodules -fcxx-modules")
}

But I continue to get an error that says:

Exception in thread "main" java.lang.IllegalStateException: Unknown option -compiler-options = -fmodules -fcxx-modules

I'm clearly just using the command wrong, but I can't find any documentation for proper use anywhere. Can someone help me out with this?

I'm trying to confirm

KotlinEnum

to

Identifiable

with the following code:

extension KotlinEnum: Identifiable {
    public var id: Int32 { ordinal }
}

but the build fails with the following:

Extension of a generic Objective-C class cannot access the class's generic parameters at runtime

I don't understand the problem, as

ordinal

has strict type

Int32

, not a generic one. How can I bypass it?

Not sure if this belongs here, or #gradle, but I'm trying to understand why our build times for release artifacts are so painfully slow. We have a multi-module, multi-platform build, and it looks like linking iOS Frameworks is taking 2/3 of our total build time. After running a build scan, it looks like our

linkReleaseFramework<Target>

tasks (

KotlinNativeLink

) are starting late in the build and executing serially, even though there are plenty of idle workers available. Things got much worse once we added M1 support since there was now yet another framework to link 😕 The

KotlinNativeLink

tasks don't seem to depend on each other in any way. Are these tasks supposed to be able to run in parallel? If so, how can I find out why they aren't for our builds? If not, is there a YT ticket for this? Screenshot/description of build scan timeline in 🧵

I’m trying to run some sql queries within a transaction by using

databaseQueries.transactionWithResult { ... }

(SQLDelight) but it throws the following error :

kotlin.native.concurrent.InvalidMutabilityException: mutation attempt of frozen kotlin.Array@10f1738

it works correctly on my android target. Am I suppose to do/use something else?

Hi everyone. I need to check app notifications settings on the device, and in order to do this, I use the following snippet for the iOS target :

actual suspend fun areNotificationsSystemEnabled() : Boolean = suspendCoroutine { continuation ->
    val settingsCompletionHandler = { settings: UNNotificationSettings? ->
        val enabled = settings?.authorizationStatus == UNAuthorizationStatusAuthorized
        continuation.resume(enabled)
    }.freeze()

    val notificationCenter = UNUserNotificationCenter.currentNotificationCenter()
    notificationCenter.getNotificationSettingsWithCompletionHandler(settingsCompletionHandler)
}

My problem here is that the “continuation” used inside the completion handler is frozen, so it crashes on the

continuation.resume(enabled)

:

Uncaught Kotlin exception: kotlin.native.concurrent.InvalidMutabilityException: mutation attempt of frozen kotlin.coroutines.SafeContinuation@80487928
[...]
    at 7   KMM                                 0x00000001071d43e0 kfun:kotlin.coroutines.SafeContinuation#resumeWith(kotlin.Result<1:0>)

I think my issue is more or less the same than this one : https://youtrack.jetbrains.com/issue/KT-43566 I don’t know if I should ask this on #coroutines but if anyone already hit this issue, I’ll be glad to hear from you 😄 Thanks !

This might be an old issue already solved in

0.7.1

https://kotlinlang.slack.com/archives/C3SGXARS6/p1528475089000678 but I wanted to get another opinion from the community. Our dynamic scanner has identified a use of private iOS API:

Frameworks/Core.framework/Core: _unsymbolicated_function accessed _NSBlock

within a KMP library module. Upon some digging, I came across this similar old issue on github with fix already merged. So my question is, has anyone else come across this? And if so, is this issue already addressed and have folks been fine publishing to App store without rejections?

Hi there, have had a look around and can’t seem to find the recommended solution to this. If I am calling an obj-C function from native, and this function returns a List<*>, (due to limited generics in obj-C), how might I cast to a DoubleArray if I know the type in the collection?

I have completely forgotten how to setup a Kotlin Native project (for a Kotlin Native program) to use a dreaded C header only library 😱. The library being used in this case is LVGL ( https://lvgl.io/ ) via its Linux Frame Buffer ( https://kevinboone.me/linuxfbc.html?i=1 ) backend. At one point I had a Kotlin Native project that successfully used a C header only library (the third party library provided some GTK Chart widgets) but can't find it 😦. @Artyom Degtyarev [JB] - Can someone please advise on how to use a C header only library in a Kotlin Native project that will generate a Linux program (an ELF binary).

Hey there! I’m trying to build a KMP project into 3 targets: arm64 (real device) plus x64 and arm64 for simulator. I’m using the

./gradlew createSwiftPackage

command, which in turn creates an xcframework using KMP’s tooling. However, the built framework only contains x64 simulator and arm64 (real device) code, so the simulator on my MacBook M1 will not run. Did anyone successfully build an xcframework for all 3 targets, that is also able to run on M1 simulators as well as on Intel simulators?

I upgraded to kotlin 1.5.31 in the last few days and I'm getting this error when compiling in iOS:

@SharedImmutable is applicable only to top level declarations

and also this one in enums:

@SharedImmutable is applicable only to val with backing field or to property with delegation

Example of data class:

data class SomeDataClass(
    @SharedImmutable val someInt: Int,
    @SharedImmutable val someString: String,
    @SharedImmutable val someBool: Boolean
)

Example of enum class:

enum class SomeEnumClass(
    /** The [Int] representation of this enum value. */
    @SharedImmutable val value: Int
) {
    @SharedImmutable ValueA(0),
    @SharedImmutable ValueB(1);

    companion object {
        internal fun fromInt(value: Int) = values().firstOrNull() { it.value == value } ?: ValueA
    }
}

After upgrading to Big Sur, the cinterop task for cocoapod dependencies is failing. Anyone have any idea what might be going on? System OS: macOS Big Sur version 11.6 Android Studio: Arctic Fox 2020.3.1 Patch 3 I tried creating a new KMM Application project using CocoaPods for the iOS framework distribution step. After creating the project a gradle sync works fine. Then I add

pod("AFNetworking")

to the

cocoapods

section of the build.gradle.kts. When I try to do a gradle sync after that the following error appears:

Execution failed for task ':shared:cinteropAFNetworkingIos'.
> Process 'command '/Users/me/Library/Java/JavaVirtualMachines/corretto-16.0.2/Contents/Home/bin/java'' finished with non-zero exit value 1

* Try:
Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':shared:cinteropAFNetworkingIos'.
	at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.lambda$executeIfValid$1(ExecuteActionsTaskExecuter.java:187)
    <36 internal calls>
Caused by: org.gradle.process.internal.ExecException: Process 'command '/Users/me/Library/Java/JavaVirtualMachines/corretto-16.0.2/Contents/Home/bin/java'' finished with non-zero exit value 1
	at org.gradle.process.internal.DefaultExecHandle$ExecResultImpl.assertNormalExitValue(DefaultExecHandle.java:414)
	at org.gradle.process.internal.DefaultJavaExecAction.execute(DefaultJavaExecAction.java:52)
	at org.gradle.process.internal.DefaultExecActionFactory.javaexec(DefaultExecActionFactory.java:198)
	at org.gradle.api.internal.project.DefaultProject.javaexec(DefaultProject.java:1145)
	at org.jetbrains.kotlin.compilerRunner.KotlinToolRunner.runViaExec(KotlinToolRunner.kt:102)
	at org.jetbrains.kotlin.compilerRunner.KotlinToolRunner.run(KotlinToolRunner.kt:77)
	at org.jetbrains.kotlin.gradle.tasks.CInteropProcess.processInterop(KotlinNativeTasks.kt:1017)
    <122 internal calls>

Anyone have some gradle magic that they use to override the filename and

spec.name

that the cocoapods plugin generates? We use an umbrella module with a name like

xcode-umbrella

but... that's not the name we want for our actual cocoapod. Setting

framework.baseName

works for the final

.framework

and the value for what's included in the Podspec, but doesn't impact the

spec.name

or actual

*.podspec

filename

I have an iOS application that uses some shared code that itself depends on a Kotlin multiplatform library. iOS.app -> shared -> library I’m trying to develop a timer that uses

CADisplayLink

in the Kotlin code. This is the code of my “timer”:

@ThreadLocal
object AppTimer {

   fun start(){
      val selector = NSSelectorFromString("execution")
      val displayLink = CADisplayLink.displayLinkWithTarget(this, selector)
      displayLink.addToRunLoop(NSRunLoop.currentRunLoop, NSRunLoop.currentRunLoop.currentMode)
   }

   @ObjCAction
   fun execution(){
      NSLog("AppTimer::Execution through CADisplayLink")
   }
}

It works without problem if the timer code is located in the shared module. But, when I move it into the library, it throws this error:

2021-10-27 13:45:35.769237+0200 iOSApp1[21754:6605253] -[App1_kobjcc0 execution]: unrecognized selector sent to instance 0x6000026025e0
2021-10-27 13:45:35.793415+0200 iOSApp1[21754:6605253] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[App1_kobjcc0 execution]: unrecognized selector sent to instance 0x6000026025e0'
*** First throw call stack:
(
	0   CoreFoundation                      0x00007fff20422fba __exceptionPreprocess + 242
	1   libobjc.A.dylib                     0x00007fff20193ff5 objc_exception_throw + 48
	2   CoreFoundation                      0x00007fff20431d2f +[NSObject(NSObject) instanceMethodSignatureForSelector:] + 0
	3   CoreFoundation                      0x00007fff204274cf ___forwarding___ + 1455
	4   CoreFoundation                      0x00007fff204297a8 _CF_forwarding_prep_0 + 120

Does anyone have an idea of why this is happening?

Looks like no dagger in kotlin-native - is there a drop-in replacement?

Is there a known issue with

xcodeConfigurationToNativeBuildType

in Gradle Cocoapods plugin in 1.5.31? In Xcode, we have a custom configuration named

Development

In Gradle, we're setting

xcodeConfigurationToNativeBuildType["Development"] = NativeBuildType.DEBUG

But we still see this in our logs:

Unable to detect Kotlin framework build type for CONFIGURATION=Development automatically. Specify 'KOTLIN_FRAMEWORK_BUILD_TYPE' to 'debug' or 'release'

It looks like it's still building the debug framework, but would love to know if • this is already known, • we're doing something wrong, • or if we should file a YT