Why are exceptions shared/jumping between Canceled Coroutines

[bedla]

Hi,
I found something interesting to me and want to know some more educated opinion on this.

We have CoroutineScope, where there are two Coroutines A and B. Both have some independent business logic and own business exception hierarchy.
When Coroutine-B is doing some work, and Coroutine-A throws some business exception, first coroutine is cancelled by "internal" kotlinx.coroutines.JobCancellationException.
What is kind of strange is that when I get rootCause I get business exception from Coroutine-A inside try/catch block inside Coroutine-B.
This means that logs or debugging is little bit misleading.

The only reasonable explanation I have is, that by this behavior it says, that Coroutine was cancelled by particular exception and Kotlin Coroutine machinery does not care that exception is from different part of business logic - it just says the state, that it was cancelled because of that exception.

Am I right? Or Am I missing something?
If yes, than it means, that catching and/or logging kotlinx.coroutines.JobCancellationException does not make sense. And another question comes to my mind is what are proper use-cases to catch JobCancellationException in the wild?

I also prepared small steps to reproduce repository here https://github.com/bedla/kotlin-coroutines-cancellation-jumping-exception

Thanks for explanation, or link to some documentation.

Ivos