How to cancel a task correctly?

[Alex0Klain]

Hello!
I don't quite understand what's wrong here. I want to cancel the previous .buildCommand action and leave the last one. .someAction can be called a lot of times and you need to leave sending only the last action. But actually when called .buildCommand, if you call .someAction again, then last .buildCommand will also be canceled for some reason. If you don't call .someAction again during this .buildCommand call, then everything will work correctly

Reducer:

   case .someAction:
    return EffectTask.concatenate(
      EffectTask.merge(
        EffectTask(value: .action1),
        EffectTask(value: .action2),
        EffectTask(value: .action3)
      ),
      EffectTask.concatenate(
        .cancel(id: CancelID.changeTemperature),
        .task {
          try? await Task.sleep(nanoseconds: 2_000_000_000)
          return .buildCommand
        }
        .cancellable(
          id: CancelID.changeTemperature
        )
      )
    )

[mbrandonw]

The problem is that you are using try? await for the sleep. When that effect is cancelled it causes Task.sleep to throw, but that error is discarded with try? and so the .buildCommand is emitted by the effect. I think you just want try await.

[Alex0Klain]

I changed to try await, but unfortunately it didn't solve the problem. So if you call .someAction during these 2 seconds while Task.sleep is active, then .buildCommand will not be sent

[mbrandonw]

I'm not sure I understand your description of what is happening versus what you expect to happen. Can you extra the code to a project that one can run and see the behavior?

[Alex0Klain]

I expect that clicking on .someAction will cancel the last one .buildCommand and go from the current .someAction. But in fact, if immediately after sending .buildCommand (within 2 seconds) click again on .someAction, then the effect of the past and current .buildCommand will be canceled.
Unfortunately, I cannot provide the project because it is under NDA :(

[mbrandonw]

Sorry I am still not understanding. I don't need access to the full project, but if you want help I think you need to show some concrete code. Try building something from scratch and share it.