Machine exit actions have been called twice

[huan]

Description

I have a machine with two children: one is spawn-ed and the other is invoke-ed.

They all have entry and exit actions which is a spy for testing.

Expected Result

after the interpreter.stop(), the parent and two children exit actions will be called once.

Actual Result

They have been called twice instead of once.

Reproduction

https://github.com/wechaty/bot5-assistant/blob/ffb902ebfa2513630a92309ce9091a28c80dbdfc/src/mailbox/xstate-child-exit-order.spec.ts#L61-L68

Additional context

I want to do cleanup whenever the machine (actor) has been stopped.

One more thing: I noticed that the exit order is not the same as the entry order.

• Entry order: spawn, invoke, parent
• Exit order: parent, spawn, invoke

I think the exit order should be exactly the reverse order of the entry?

[Andarist]

Have you tried with 4.27.0? This should have been just fixed there: https://github.com/statelyai/xstate/releases/tag/xstate%404.27.0

[huan]

@Andarist Thank you very much for the information!

I can confirm that this issue has been fixed by the 4.27 (#2895), appreciate your fix!

[huan]

And may I ask your option for the exit order is not as same as the entry order problem?

• Entry order: spawn, invoke, parent
• Exit order: parent, spawn, invoke

I think the exit order should be exactly the reverse order of the entry, or do we have any reason that make those order like this?

[Andarist]

The exit actions order is being fixed here: #2903

[huan]

Aha, brilliant!