Guide: withTimeout: missing info on statements being executed in atomically

[arberg]

I'm learning, I read the withTimeout and it's claim that the second example will not leak resources. This can only be true if kotlin coroutines withTimeout guarantees that a statement is atomic, either it executes completely (including the assignment) or not at all. It would be nice if this was explicitly stated, and possibly with link to details if it's not so simple.
https://kotlinlang.org/docs/cancellation-and-timeouts.html

Otherwise really nice and clear writeup. Thank you to whoever wrote it.

[dkhalanskyjb]

The specifics are covered in the same document, in the "Cancellation is cooperative" section. Statements are definitely not atomic in general (some function that is part of a statement could have checked whether the job is cancelled), and this is true not only about withTimeout but about any suspend function.

The reason why that particular example works is that nothing on the resource = Resource() line checks whether the job was cancelled, and since cancellation is cooperative (that is, the code can not be forced to stop executing, it must check on its own whether it should), this line of code will ignore cancellations.

[arberg]

Ah right, that makes sense, thank you. That would be a perfect addition to the document, just pointing in the direction that its because cancellation is cooperative and thus the job runs till it finishes, but the result is discarded upon cancel.