rasa: use_entities is broken when domain is split

Rasa Open Source version

2.8.12

Rasa SDK version

2.8.2

Rasa X version

No response

Python version

3.8

What operating system are you using?

Linux

What happened?

Create a domain.yml with the following content:

intents:
  - greet:
      use_entities: [country]
  - goodbye:
      use_entities: []
  - affirm
  - deny
  - mood_great
  - mood_unhappy
  - bot_challenge
 
entities:
  - city
  - country

Create another domain yaml with the following content:

intents:
  - inform:
      use_entities: [city]

Reading the merged domain files using Domain.load shows that the intent inform is still using the entities city and country.

The workaround is to repeat the list of entities in the first domain file in the second domain file i.e.:

intents:
  - inform:
      use_entities: [city]

entities:
  - city
  - country

Here is the code to reproduce this behavior.

Command / Request

No response

Relevant log output

No response

Definition of done

• Fix bug in 2.8 and 3.0
• Create integration test to ensure this works as expected
• Fixed merged into 2.8 and 3.0