I have a code like this:

launch {
  try {
    myCoroutine() // throws exception when executed
  } catch (e: Exception) {
    println("caught $e")
  }
}

and instead of catching it crashes. But if I replace try/catch with

runCatching { myCoroutine() }.exceptionOrNull()?.let { println("caught $e") }

it catches and prints exception. Now,

myCoroutine

above involves calling android-related Retrofit library which has it's own coroutine adapters, so it might be doing some smarty stuff (debugger shows that

continuation.resumeWithException()

is called, maybe on different dispatcher), but I want to understand in general the difference between

try/catch

and `runCatching`: why can this situation happen and when I should use which approach to handling exceptions?

are you sure it's not throwing a

Throwable

instead of

Exception

?

hahaha, omg, that's it! I twisted my head in so many ways trying to understand what the hell happens here 🙂

Just be mindful that when Coroutines get cancelled, a

CancellationException

gets thrown. However it will not cause a crash. If you catch

Throwable

be sure to re-

throw

it if it is an instance of

CancellationException

so that the Coroutine cancels correctly. Otherwise you'll be treating the cancellation as is it were an actual error.

Thank you!

You're welcome 🙂