Using immediate AND transition

[arggh]

I apologize if this is a silly question, I just got started with robot.

I wrote this state machine (codesandbox here) and it didn't work as I expected:

const canSubmit = () => false; // will never approve!
const machine = createMachine({
  idle: state(transition("submit", "validate")),
  validate: state(
    immediate("submission", guard(canSubmit)),
    transition("revalidate", "submission", guard(canSubmit))
  ),
  submission: state()
});

What I thought would happen

After sending submit, I expected the machine to be in validate state, waiting for the revalidate transition.

What happened

Machine went back to idle

Why it's strange

In the guide, there's this code:

const machine = createMachine({
  idle: state(
    transition('submit', 'validate')
  ),
  validate: state(
    immediate('submission', guard(canSubmit)),
    immediate('idle') // <--- you can omit this line if you want to?
  ),
  submission: state()
});

...but to go back to idle then the guard prevents proceeding to 'submission', it's completely unnecessary to call immediate('idle'). The machine will go back to idle without it, too.

Is there a fault in my thinking, or a fault in the robot?🤔

[Matthew Phillips]

Interesting. I sort of expect what you expect as well. I'll look at the tests and the code and get back to you.

[Matthew Phillips]

It's a bug, fix coming soon.

[Matthew Phillips]

Fixed in https://github.com/matthewp/robot/releases/tag/v0.2.12, thanks for finding this interesting bug!