Wondering what would be the idiomatic way to launch multiple coroutines in a `supervisorScope` while...

# coroutines

[Patrick Steiger]

Wondering what would be the idiomatic way to launch multiple coroutines in a supervisorScope while still capturing all exceptions (aggregated) that are thrown in them.

Note that I do not want failure of a child to cancel other children (or the scope), hence supervisor scope, but I might want to “sum” (probably addSuppressed) all exceptions and throw it later after scope is done

Right now I’m using withContext with a custom CoroutineExceptionHandler that puts all exceptions in a collection and later reduce the collection and throw, but it just feels boilerplate-y and wonder if I’m missing something

[Sam]

How would you write this if you weren’t using coroutines? Maybe instead of having the child coroutines fail, you could instead have them return something like a Result.

[Patrick Steiger]

I think adding the async to a list and then mapNotNull { runCatching { it.await() }.exceptionOrNull() } is indeed cleaner, then I can return a list of Throwable to join and throw later

[kevin.cianfarini]

don’t use runCatching in coroutines code. It can capture CancellationException and break structured concurrency.

See: https://github.com/Kotlin/kotlinx.coroutines/issues/1814