really stupid question, but i can’t find an answer by googling… Are there any guarantees on order of execution when using a single threaded coroutine dispatcher? e.g.:

val dispatcher = Executors.newSingleThreadExecutor().asCoroutineDispatcher()
val scope = CoroutineScope(dispatcher)

for (i in 1..5) {
    scope.launch {
        println(i)
    }
}

Because your

CoroutineDispatcher

is based on a Java single thread executor, coroutines are executed sequentially, in the order of submission. Note that this is not guaranteed for all

CoroutineDispatcher

implementations.

okay, thank you 🙂

people often will be really cagey about answering this question because if you find yourself relying on the order of resumed continuation execution instead of more explicitly controlling your desired ordering, you're likely to be in for some headaches down the road

It's easier to assume that there is no guarantee of sequential execution rather than rely on dispatcher implementation

Agreed, if you don't want your code to be asynchronous from each other, you should write your code to be sequential in the first place.