Gracefully handle when intents in stories.yml or rules.yml have no value

[sentry-io]

Sentry Issue: RASA-OPEN-SOURCE-9YN

Stack Trace

AttributeError: 'NoneType' object has no attribute 'strip'
(22 additional frame(s) were not displayed)
...
  File "rasa/shared/core/training_data/story_reader/yaml_story_reader.py", line 258, in _parse_plain_item
    self._parse_step(step)
  File "rasa/shared/core/training_data/story_reader/yaml_story_reader.py", line 279, in _parse_step
    self._parse_user_utterance(step)
  File "rasa/shared/core/training_data/story_reader/yaml_story_reader.py", line 314, in _parse_user_utterance
    utterance = self._parse_raw_user_utterance(step)
  File "rasa/shared/core/training_data/story_reader/yaml_story_reader.py", line 414, in _parse_raw_user_utterance
    intent_name, full_retrieval_intent = self._user_intent_from_step(step)
  File "rasa/shared/core/training_data/story_reader/yaml_story_reader.py", line 373, in _user_intent_from_step
    user_intent = step.get(KEY_USER_INTENT, "").strip()

Further Information

This error can be reproduced if we have an intent with no value :

in rules.yml like shown below

version: "2.0"
rules:
  - rule: Greet user
    steps:
      - intent:
      - action: utter_greet

or in stories.yml like shown below

version: "2.0"
stories:
  - story: stop form + continue
    steps:
      - intent:
      - action: restaurant_form

** Command that led to error**:

rasa train

Potential Solutions

• Add a check in the code which checks that step.get(KEY_USER_INTENT, "") has a value and otherwise it raises :
  • an InvalidRule error if the object is a RuleParser
  • an InvalidStory error if the object is a StoryParser

Fun Fact

• The function _user_intent_from_step has an argument called step and python debugger pdb has a command called step. So if someone wants to debug with pdb while being inside that function and tries to see what the variable step has by giving (Pdb) step tough luck! It will just move on the next statement. Temporarily renaming the argument works though. :)

[ancalita]

PR merged to 2.6.x