Hi All, I seem to have an issue with Coroutine Ex...

# coroutines

[Sean Keane]

Hi All,

I seem to have an issue with Coroutine Exception handler. I have created a scope that accepts a response callback.

internal class MainScope<T>(private val coroutineContextProvider: CoroutineContextProvider, private val response: (Response<T>) -> Unit) : CoroutineScope {
    override val coroutineContext: CoroutineContext
        get() = coroutineContextProvider.context() + job + exceptionHandler

    private val job = SupervisorJob()

    //This needs more investigation with thread scope
    private val exceptionHandler = CoroutineExceptionHandler { _, throwable ->
        logWarn(throwable.message.orEmpty())
        response.invoke(Response(error = throwable, value = null))
    }
}

When an exception occurs I want to capture it and pass it back through the response object.

class Response<out T>(val value:T?, val error: Throwable? = null) {

    fun isSuccess(block: (T) -> Unit): Response<T> {
        value?.let(block)
        return this
    }

    fun isFailure(block: (Throwable) -> Unit): Response<T> {
        error?.let(block)
        return this
    }

}

But the exception handler never gets called when a failure occurs.
This is how I launch.

MainScope(coroutineContextProvider, onResponse).launch { 
 //CODE
}

Am I missing something for handling the exception or should it just be captured when an exception occurs

[fatih]

Why do you need to create your own scope? I think it seems like this can be done with giving your own exception handler directly to scope. For instance

val handler = CoroutineExceptionHandler{ context, exception -> response.doSomething(exception) }

And give it like scope.launch(handler) {...}

[Sean Keane]

I'll try that and see, I need to inject the same context so I can test so need them together.

[Sean Keane]

Found the issue. I had a run catching inside a class preventing the exception being thrown