Problem with slot list in forms

hello guys, to consolidate my knowledge in rasa i’m developing a bot for a pizzeria. To collect order information, I am using the form. Since a pizza can have up to 4 different flavors, I created a list type slot to store them. When the user types the desired flavors, the form stores the list in the “tops” slot, but on the next iteration of the form the list elements just disappear, does anyone know what might be going on?

here is the domain:

      - entity: tops
        type: from_entity
      - entity: size
        type: from_entity
      - type: from_text
- border
- drink
- size
- tops
    type: text
    influence_conversation: true
    type: list
    influence_conversation: true
    type: any
    influence_conversation: false

here is the “tops” validation:

def validate_tops(
        slot_value: Any,
        dispatcher: CollectingDispatcher,
        tracker: Tracker,
        domain: DomainDict,
    ) -> Dict[Text, Any]:
        """Validate `pizza_type` value."""
        if len(slot_value) == 0:
            return {"tops": None}
        if len(slot_value) > 4:
            dispatcher.utter_message(text=f"Desculpe, só servimos pizzas de até 4 sabores")
            return {"tops": None}
        for top in slot_value:
            if top.lower() not in ALLOWED_PIZZA_TOPS:
                dispatcher.utter_message(text=f"Desculpe, não temos a opção { top }, você pode escolher entre {'/'.join(ALLOWED_PIZZA_TOPS)}.")
                return {"tops": None}
        dispatcher.utter_message(text=f"Ok! uma pizza de {'/'.join(slot_value)}.")
        return {"tops": slot_value}```


on the next iteration of the form the list elements just disappear

Could you please clarify this statement by providing the full debug log? Did I understand correctly that when you activate the form in the same conversation a 2nd time, the tops slot is requested again because it’s empty?

Also please confirm your rasa & sdk version.

Yes, I had the same problem. The list is override with an empty one. Check this thread.

Thanks guys, I I implemented it in another way, changing tops slot to text type.

Can you please help me with your code, i still can’t fix the error