Hi guys, I often find it pretty useful to catch lo...

# coroutines

[Joffrey]

Hi guys, I often find it pretty useful to catch low-level exceptions and wrap them into more meaningful higher-level exceptions:

try {
   // some suspending operations to connect to web socket
} catch(e: Exception) {
   throw WebSocketConnectionFailedException("meaningful high-level msg", e)
}

But when coroutine machinery like withTimeout is used around this code, it doesn’t behave as expected (we’re expecting a TimeoutCancellationException but get another one).

To solve this problem, I add an extra catch to rethrow CancellationException as-is, but it doesn’t feel right…

try {
   // so some operations to connect to web socket
} catch(e: CancellationException) {
   throw e // no wrapping here
} catch(e: Exception) {
   throw WebSocketConnectionFailedException("meaningful high-level msg", e)
}

Is there a better / built-in way to do this?

[marstran]

The other way would be to catch a more specific exception than Exception, and pass everything else through.