Hi, am I right that there's no way to distinguish whether a `CancellationException` is caused by a f...

# coroutines

[louiscad]

Hi, am I right that there's no way to distinguish whether a CancellationException is caused by a function call or by the cancellation of the coroutine scope?
I'd like to handle cancellation caused by a function call without stopping suspending iteration, unless the whole scope is cancelled (because the Activity is destroyed)

[elizarov]

What do you mean “caused by a function call”?

[elizarov]

CancellationException is only thrown when the scope (job) is cancelled

[louiscad]

Caused by calling cancel() from a CompletableDeferred that is awaited.

I had a while(true) try { ... } catch(e: Exception) { ... }, but I added a coroutineScope { ... } and did a while(isActive) instead to fix. BTW, I realized I could have made an infinite cancellation loop by adding cancellation support to a method without allowing cancellation to ever succeed.

[elizarov]

The convention is that CancellationException is thrown on cancellation. So if you are writing an infinite loop and you want it to be cancellable, then you can either check for isActive or break when you catch CancellationException

[louiscad]

Yes, but I caught it, without rethrowing it, and moved on to the next iteration, which began in the try block that would throw the CancellationException, then caught again, and so on...

Reading your words, I think I'm realizing it's not a good idea to throw a CancellationException that can't be disambiguated by its type like TimeoutCancellationException can for things like an alert dialog being dismissed so I'll create a CancellationException subclass and cancel the CompletableDeferred with it, so a coroutine calling it can recover safely if needed.