[Question] Is it possible to create a LifecycleRegistry on Desktop using `kotlinx-coroutines-swing` dependency but without having to call the `createUnsafe` function?

[luanrodrigsr]

Describe the bug Hi!

I'm trying to achieve something like this:

abstract class Application : ViewModelStoreOwner(), LifecycleOwner {
     private lateinit var lifecycleRegistry: LifecycleRegistry

     // ...

     private fun createLifecycle() {
          lifecycleRegistry = LifecycleRegistry(this)
     }

     private fun create() {
          if (lifecycle.currentState == Lifecycle.State.INITIALIZED) {
               lifecycleRegistry.currentState = Lifecycle.State.CREATED

               log.d { "Application created!" }

               onCreate()
        }
    }

     // ...

     companion object {
          internal inline fun <reified T : Application> create(): T {
               val instance = T::class.createInstance()

               instance.createLifecycle()
               instance.create()

               return instance
          } 
     }
}

The code works pretty well, but then when i add the org.jetbrains.kotlinx:kotlinx-coroutines-swing dependency to the commonMain, the line where i need to update the lifecycle state doesn't work (lifecycleRegistry.currentState = Lifecycle.State.CREATED). It only works if i call the function LifecycleRegistry.createUnsafe(this) on the createLifecycle method.

Maybe it got something to do with the thread, but i'm not sure. 😅

Is it possible to create a LifecycleRegistry on Desktop using kotlinx-coroutines-swing dependency but without having to call the createUnsafe function?

Thank you!

Affected platforms

• Desktop (Windows)

Versions

• Kotlin version*: 1.9.23
• Compose Multiplatform version*: 1.6.10-beta01
• OS version(s)* (required for Desktop and iOS issues): Windows 11 23H2
• JDK (for desktop issues): JBR-17 17.0.9

Additional context Lifecycle ViewModel Compose version: 2.8.0-alpha01 Navigation Compose version: 2.8.0-alpha01

[pablichjenkov]

kotlinx-coroutines-swing should go in jvmMain/desktopMain dependecies block.

[luanrodrigsr]

Hey @pablichjenkov, thanks! I updated my build.gradle.kts files, but still couldn't get the code to work.

[pablichjenkov]

I think you misunderstood my previous comment. You have either jvmMain or desktopMain not both. Need to add swing dependecy in one of them. Are you using jvmMain or desktopMain?

[luanrodrigsr]

Oh. I tried both of them, separately. Not at the same time.

I am using desktopMain right now, by the way.

[pablichjenkov]

Oh. I tried both of them, separately. Not at the same time.

I am using desktopMain right now, by the way.

Ah ok sorry I misunderstood you. Can you post the errors you are getting

[luanrodrigsr]

The code after the lifecycleRegistry.currentState = Lifecycle.State.CREATED line is not being executed. Which is preventing the "Application" for being created. It only happens when i use the kotlinx-coroutines-swing dependency.

But, when i updated the code on line 75 to LifecycleRegistry.createUnsafe(this), it works fine. (Pay attention to the debug panel which shows the enforceMainThread field set to false. Looking at the source code, this parameter is present in the private constructor of the LifecycleRegistry, that is (i believe) supposed to be always true).

The documentation says that the method createUnsafe:

Creates a new LifecycleRegistry for the given provider, that doesn't check that its methods are called on the threads other than main. LifecycleRegistry is not synchronized: if multiple threads access this LifecycleRegistry, it must be synchronized externally.

Considering all this, I may not be fully aware of the implications that using the createUnsafe method can bring. Except for the fact that "if multiple threads access this LifecycleRegistry, it must be synchronized externally".

[luanrodrigsr]

To add more context, what I'm trying to achieve is to create a custom implementation of the LifecycleOwner interface in an abstract Application class that will be responsible for controlling the lifecycle of the desktop app (outside of compose). I needed to add the kotlinx-coroutines-swing dependency because of the "Module with the Main dispatcher is missing" (#4653) error.

[pablichjenkov]

I see, Humm 🤔 seems like a problem inside LifecycleRegistry constructor. You are basically having a silent crash or so. It is hard to predict with logs or more information. I would start by checking the implementation of LifecycleRegistry.

[luanrodrigsr]

Thank you. I will try to dig into the implementation.

I just wanna note that the enforceMainThread being set to false on the example i gave is working as intended, I think, since it is the role of the createUnsafe method.

This makes me wonder if the right way to create a LifecycleRegistry, in my case, wasn't using the public constructor which sets this field to true . I am just too worried about the inability to do so. I mean, the lifecycle registry is created, but I'm unable to interact with it.

[kropp]

Hi @luanrodrigsr I confirm that this is a bug in Lifecycle implementation for desktop target. The good news is that it is already fixed, however, the fix is not yet published. I tried your snippet on the newer version and it now works. Currently, I would expect it to be available Lifecycle 2.8.0-rc01 release and the subsequent Compose 1.6.10-rc01 release.

[luanrodrigsr]

Thank you! @kropp

[okushnikov]

Please check the following ticket on YouTrack for follow-ups to this issue. GitHub issues will be closed in the coming weeks.