Hello Just wanted to warn anyone who is integrating Coroutin

Question

Hello Just wanted to warn anyone who is integrating Coroutines Flow into an existing RxJava based code base that `ObservableSource asFlow ` has proven at least for me to be quite unsafe and can even crash your app I have several stack traces in <https github com Kotlin kotlinx coroutines issues 2104>

Marcelo Hernandez · Answer

It seems that using this extension within streams that leverage `combine` or `flatMapLatest` or any operators that cause downstream cancellations where `ObservableSource asFlow ` is used in the downstream may run into race conditions where the Coroutine might get cancelled concurrently while the Rx `Observable` is still emitting causing a `JobCancellationException` or a `ChildCancelledException`

Marcelo Hernandez · Answer

I wish I had a solid and consistent repro but unfortunately that is currently not the case disappointed

wbertan · Answer

I got what I think similar case with Rx disappointed In my case I did `dispose` which then something finished and throw exception and I got `io reactivex exceptions UndeliverableException` The code contains a proper error handler where usually was the reason for this error So I found this issue in GitHub <https github com ReactiveX RxJava issues 4991> with this comment gt This is by design your Callable crashes and the downstream has disposed so the operator routes the error to the global error handler as it can t know if the exception is relevant or not Don t crash into RxJava and consider using create with emitter tryOnError instead

wbertan · Answer

The problem in my case the Callable crash was in Retrofit as the exception is ```Caused by retrofit2 adapter rxjava2 HttpException HTTP 404 Client Error``` So not sure if in my case I would be able to handle better as the comment suggests with `create ` and `emitter tryOnError ` Anyway it was the first time we notice this kind of Exception like this and it was in our Alpha build internal so we will keep an eye and if becomes more often we will act on it

Marcelo Hernandez · Answer

Interesting scenario thinking face

Marcelo Hernandez · Answer

The `ObservableSource asFlow ` crasher has been fixed and will be included in the Coroutines 1 4 release tada Thanks < louiscad> < Tash> and < Vsevolod Tolstopyatov JB > clap