Hello for all! Can anybody help with error "kotlin.native.concurrent.InvalidMutabilityException: mutation attempt of frozen". Problem is that object is created in main thread on iOS and exception thrown from constructor. When and why object become frozen?

You can find more info here: https://github.com/JetBrains/kotlin-native/blob/master/CONCURRENCY.md What's your concrete code?

I already read this article I don't wee why objects become frozen: it is not global variable and song object definition, it references to static object but as I understand it should not make it frozen. They are not objects but classes, instance is created in AppDelegate.application, code is very big, I can't show all. Initially that was framework developed as multiplatform, but tested only in Android.

Could you please provide more info about what's your class is and how it's created. Some code would be nice.

You can use ensureNeverFrozen to see an exception thrown on what freezes the object. https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.native.concurrent/ensure-never-frozen.html

OK, thanks 🙂 I'll try it

You could make an expect/actual for the function? In the past I found some issues with freezing this way in my common code. I remember mostly being caused by code inside an object or by Lambdas being passed with an unneeded scope which was later frozen.

Thanks. Already done that but it sill crash with "Mutation attempt of already frozen object MyClass" when MyClass have init { ensureNeverFrozen() }

What is "listener for another thread"? Please provide some piece of code.

Is

MyClass

a

class

or an

object

? If it is a

class

then where is an instance of it created?

MyClass

is a class, instance is created in AppDelegate.application() method

And where is the instance stored?