Hello all. We have a KMM project and try to run th...

# ios

[Philipp Bykow]

Hello all.
We have a KMM project and try to run the App on iOS but when executing the following error comes Function doesn't have or inherit @Throws annotation and thus exception isn't propagated from Kotlin to Objective-C/Swift as NSError. and crashes the App. In the class init we call something like this

coroutineScope.launch {
    test()
}

The test function is as followed:

@Throws(Exception::class)
    private suspend fun test() {
       ...
    }

[kpgalligan]

Well, the short answer is you have a crash in your Kotlin code which makes its way to the “Swift/Kotlin” border, at which point it falls over. Whatever calls the coroutineScope.launch from Swift is failing. It’s probably wrapping and throwing whatever test() throws.

[kpgalligan]

To just get logs, I’d wrap coroutineScope.launch call with try/catch, print that stack trace, then rethrow.

[kpgalligan]

You should only add @Throws if you want to bubble errors up to Swift. However, you’ll need to use explicit try calls from Swift. Exceptions in that context are very different. We basically don’t use @Throws

[kpgalligan]

This isn’t directly about the topic, but sort of adjacent, about how the different platforms handle exceptions: https://www.kgalligan.com/crash-reporting-and-kmp/

[Philipp Bykow]

Hello @kpgalligan, thank you i will try the try/catch you suggested.