Hi guys, I was playing with `withTimeout` function and I’ve noticed that if the block inside is not ...

# coroutines

[Andrea Giuliano]

Hi guys, I was playing with withTimeout function and I’ve noticed that if the block inside is not a suspending function, withTimeout simply does nothing.
Is that the expected behaviour? I know from the spec it’s stated that the block is a suspending block. However I was expecting at least some error or warning if the block is not suspending. Anything I’m missing here?

[streetsofboston]

withTimeout (or any cancellation of a coroutine) can only cancel a currently suspending function. It cannot cancel a blocking function.

[Andrea Giuliano]

yeah I got that and it makes sense. Problem is I believe it’s very error prone. I could figure this out thanks to unit tests since I was expecting a compilation error saying that the block is not suspending

[streetsofboston]

The compiler wouldn't know that.... Blocking code is not marked as such...

There is a lint warning for when you call code that throws an IOException in a Coroutine for which it is not immediately clear that its dispatcher is Dispatchers.IO.... often this warning is wrong and not very useful...

[louiscad]

You can use withTimeout + runInterruptible if the blocking code is interruptible though.

[Andrea Giuliano]

that’s super @louiscad thanks for sharing