Debugging Rasa Errors

This is a short summary of the "random" Rasa and python errors (and what to look for to fix them) you will no doubt encounter when you're developing a chat bot using Rasa. Some are pretty obscure, and after some time you'll get used to identifying them, and other times no so much.

I'll admit, this post is pretty selfish, it is more for me to have a location bookmarked that I can reference from time to time when I can't remember, but I know it'll help someone new or old to the Rasa scene.

I've posted this as a repo as well (https://github.com/jwheat/rasa-errors), so if you have any updates / corrections / or new errors I've missed (now that there's a new Beta out) feel free to issue a pull-request and I'll get them merged in.

Now without further rambling, here are the errors, in no particular order, other than the order I've encountered them over the last few months when I was compiling this.

AttributeError: 'str' object has no attribute 'setdefault'

File "c:\users\jonathan\anaconda3\envs\rasa\lib\site-packages\rasa\core\domain.py", line 290, in _transform_intent_properties_for_internal_use
    properties.setdefault(USE_ENTITIES_KEY, True)
AttributeError: 'str' object has no attribute 'setdefault'

Type: Syntax Error

File: domain.yml

Where to look: intents: - specifically use_entities: []

Solution:

• Make sure there is a space between the : and the []
• Make sure your use_entities: [] is indented properly under the parent intent name. Here's an example of good indenting practices

intents:
  - enter_data:
    use_entities: []

AttributeError: 'bool' object has no attribute 'get'

File "c:\users\jonathan\anaconda3\envs\rasa\lib\site-packages\rasa\core\domain.py", line 265, in collect_slots
    slot_class = Slot.resolve_by_type(slot_dict[slot_name].get("type"))
AttributeError: 'bool' object has no attribute 'get'

Type: Syntax Error

File: domain.yml

Where to look: slots:

What the problem is: indenting slot properties

Solution: you need an ever increasing set of indents for slot definitions. Make sure your type and auto_fill, initial_value and any other properties of a slot are indented under the slot name

What I've done: I utilize past code a lot, and VSCode likes to automatically indent when you past a block that has indening, so many times my indenting is off and I'm in a rush and don't see it is incorrect. Needless to say, this error is my most frequent.

Here is an example of proper slot indentation

slots:
  customer_first_name:
    type: unfeaturized
    auto_fill: true

pykwalify.core - ["Value 'None' is not a dict. Value path: '/slots'"]

Type: Syntax Error

File: domain.yml

Where to look: slots:

What the problem is: indenting slot name, and/or missing - if your slot happens to be a list or array

Solution: Similar to the above error, you need an ever increasing set of indents for slot definitions with proper - hyphens as well. Make sure your slot name is properly indented under the slots: key and double check your hyphens o be sure they're all there (or not)

What I've done: Sometimes even though you have your hyphens, the indents are still off. I have some custom slots that have dictionaries (multiple hyphenated items) and sometimes I forget the -

Here is an example of proper slot indentation

slots:
  risk_level:
    type: categorical
    values:
      - low
      - medium
      - high

rasa.core.actions.action - Failed to extract slot customer_first_name with action form_change_customer_first_name

Type: spelling / naming error

File: actions.py, domain.yml

Where to look: python slot code in your actions.py and specifically the slot names in your domain.yml

What the problem is: slot name mismatch (aka typo)

Solution: - this is more than likely a naming / spelling issue. Make sure the slot name you're referencing in your actions.py file MATCHES to the slot and/or response in your domain.yml file.

What I've done: Sometimes I'll write python code for a new slot, and forget to add it to my domain.yml file, or I'll rename it in my head and forget to update it somewhere.

TypeError: 'NoneType' object is not iterable

Type:

File: actions.py

Where to look: required_slots method

What the problem is:

Your required slots does not return anything. You may have some nested if logic, and chances are whatever path you just took in chat, resulted in a path that did not return anything.

Solution:

A quick hack, not advisable is to add a return [] to the end of your required_slots method. This catch all will always return an empty list, and satisfy the actual functionality of this method.

The better solution is to trace your if logic and handle the path you took in chat, and return an actual list (even one) of requiredSlots

Check out the repo (https://github.com/jwheat/rasa-errors) for any updates to this, or send me a pull-request if you have changes, or new errors to add!