Why does `Task.waitAll` require a non-empty array of tasks?

[jreut]

Task.waitAll([]) fails with an error saying it requires a non-empty array of tasks. To my mind, Task.waitAll([]) is a Task that will always resolve to [], just like Task.waitAll([Task.of(42)]) is a Task that will always resolve to [42].

I might be missing something, though. What is the motivation behind failing on an empty array? I'm happy to submit a patch if this behavior could indeed be changed.

Thanks!

[robotlolita]

That's correct. Task.waitAll([]) would resolve to the empty array. Originally this (and Task.waitAny) were designed for the static case, where you know which tasks you're passing there, so an empty array is an obvious error. But that's not necessarily the case for a dynamic case, where you get an arbitrary array containing tasks from elsewhere, and you might want to resolve that to an empty array if they're empty.

I don't really feel strongly either way, so this behaviour could change to support the latter use case. My only reservation right now is with Task.waitAny not having a similar empty value, and thus Task.waitAll([]) wouldn't throw an error, whereas Task.waitAny([]) would have to, since returning a Task that never resolves there would make finding accidental empty arrays difficult.