Merge pull request #2945 from MycroftAI/refactor/race-condition-comment

Added comments to document race condition

mycroft/skills/mycroft_skill/mycroft_skill.py

@@ -411,7 +411,16 @@ def converse(self, message=None):
  return False
 
  def __get_response(self):
- """Helper to get a reponse from the user
+ """Helper to get a response from the user
+
+ NOTE: There is a race condition here. There is a small amount of
+ time between the end of the device speaking and the converse method
+ being overridden in this method. If an utterance is injected during
+ this time, the wrong converse method is executed. The condition is
+ hidden during normal use due to the amount of time it takes a user
+ to speak a response. The condition is revealed when an automated
+ process injects an utterance quicker than this method can flip the
+ converse methods.
 
  Returns:
  str: user's response or None on a timeout

test/integrationtests/voight_kampff/features/steps/utterance_responses.py

@@ -235,6 +235,12 @@ def check_contains(message):
 @then('the user replies "{text}"')
 @then('the user says "{text}"')
 def then_user_follow_up(context, text):
+ """Send a user response after being prompted by device.
+
+ The sleep after the device is finished speaking is to address a race
+ condition in the MycroftSkill base class conversational code. It can
+ be removed when the race condition is addressed.
+ """
  wait_while_speaking()
  time.sleep(2)
  context.bus.emit(Message('recognizer_loop:utterance',