Propagate resetState to canceled child tasks

[jelhan]

It seems that there isn't an option to reset the state of child tasks when canceling a parent task.

Assuming I have a parent and child task like this:

class Foo {
  @task
  *parent() {
    yield this.child.perform();
    return 'foo';
  }

  @task
  *child() {
    return 'bar';
  }
}

I can reset the state of the parent task when canceling it by passing { resetState: true } option:

cancel() {
  this.parent.cancelAll({ resetState: true });
}

But that option does not seem to propagate to cancellation of the child task.

As a work-a-round I need to cancel the child task manually and pass the { resetState: true } option to it as well:

cancel() {
  this.child.cancelAll({ resetState: true });
  this.parent.cancelAll({ resetState: true });
}

It would be great if I the resetState option propagates to all child tasks instead. Maybe controlled by another option for cancelAll.

[maxfierke]

This is a great idea! I could see cases where you might not want this behavior, but it makes sense that the default should probably be to reset child task state too.

[machty]

class Foo {
  @task
  *parent() {
    yield this.child1.perform();
    yield this.child2.perform();
    yield this.child3.perform();
    return 'foo';
  }
  // ...
}

Let's say parent is cancelled while awaiting child2; is the idea that child1 (in additional to child2) would have its state reset because it was previously performed by child1?

I can imagine some trickiness in the mental model and potentially how we implement this if, say, other tasks might be calling child1 directly; and we might not be able to say this is a backwards-compatible change.

[maxfierke]

I can imagine some trickiness in the mental model and potentially how we implement this if, say, other tasks might be calling child1 directly; and we might not be able to say this is a backwards-compatible change.

agreed. it's definitely a change that would have to come under a toggle of some sort or next major release. would also add that it might make sense to have it entangled w/ linked() vs unlinked() on it too (i.e. unlinked() shouldn't trigger that behavior), but also there should be an opt-out at the cancelAll level too (e.g. cancelAll({ resetState: true, skipChildren: true }) or something