A modern programming language that makes developers happier.

kotlinlang

So I just switch to `Dispatcher.Default` from `<http://Dispatcher.IO|Dispatcher.IO>`  to handle a `ProcessBuilder`  and got this recommendation from the intellij idea: `Possibly blocking call in non-blocking context could lead to thread starvation` . I used `waitFor` on the `ProcessBuilder`  so it's probably why the idea suggested to switch back to `<http://Dispatcher.IO|Dispatcher.IO>` , does the idea suggest this for every operation that gonna block the thread its run on without knowing whether the operation depend on CPU or IO more?

`ProcessBuilder` creates a new external process that doesn't use your current process's resources. Your current thread should use `IO` dispatcher to wait for the external process because the current thread is not computing anything; the current thread is only waiting.

It is very much the same situation as if your external process were replaced by a remote server that you access via the internet. Your current thread is waiting for input/output from something external, so it should use `IO` dispatcher. It doesn't matter if the external process/server is doing its own CPU work.

>  does the idea suggest this for every operation that gonna block the thread its run on without knowing whether the operation depend on CPU or IO more
It's correct, this check is not very sophisticated, it mostly relies on what kind of exceptions specific function throws

And as Ryan mentioned, you just need IO here

You also should use runInterruptible, so it will work better with coroutines cancellation, because waitFor is a code with thread interruption support
<https://kotlinlang.org/api/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutines/run-interruptible.html>

<@U0BRK9HC5> I see, what will happen to the calling coroutine if `waitFor` return an `InterruptedException` in the case that I don't use `runInterruptible` ?

If coroutine where you run would be cancellable, waitFor continue blocking coroutine and thread

How is that the cancelled coroutine still be blocked by `waitFor` and not get GC-ed? 

because thread is blocked, it does work, cannot be reused for anythign else with cancellign task