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What is the reason behind `objects` being _frozen_ - technical limitation or a language concept?
What us then the alternative of keeping the global modifiable list of, say, users in the app?

Frozen objects are immutable, immutable objects are thread-safe, thread-safe objects remove multi-threading bugs

I see the logic here, but how do I implement [mutable] singleton multithreaded component in Kotlin?

AtomicReference? <https://medium.com/@kpgalligan/kotlin-native-stranger-threads-ep-2-208523d63c8f>

Notify me if this helps, I'm also interested in solution but I don't have time to allocate to this right now

What's preventing you from declaring the fields inside an object as `var`, or setting a mutable object (like a `MutableList`) as a field?

Hm.. just checked - I have my mutable list declared inside the object like ` private val fetchers: ArrayList&lt;DataSourceFetcher&gt; = ArrayList()` . Will try the same using `var`and report.

Once an object is frozen, all its children objects are also frozen. The only way to have mutable properties in an `object` for mutable singletons is to use `AtomicReference` or other atomic data structures. I was fighting this a while ago and that really is the only route, unfortunately

Oh, is this a KotlinJS or Android thing? Because JVM objects are just singletons. I just tested out some code with a mutableList field in an object.

<@U5N0JPBEE> This is a Kotlin/Native memory model restriction

Any ideas why `AtomicReference` is not available for me? Kotlin '1.3.30'

According to documentation - it should be in both Common and Native.

There's atomicfu that should have multiplaform atomic ops <https://github.com/Kotlin/kotlinx.atomicfu>

Not sure if that is the right way to go. Can somebody help? <@U0AAQKT9Q>

<@UD17D4K8W>
&gt; Once an object is frozen, all its children objects are also frozen.

Is there any option to distinguish between real children (owned) and referenced objects? Currently if I pass some object in constructor to the frozen object, that one is also get frozen which is not what I want.