Description

The generated Python client does not properly return the final classes when multi-level inheritance is used.

For example:

• When GET /pet returns any of AngryDog, NiceDog, and FunnyCat object, the Python client will return a Pet object (without all final_type-specific attributes missing).
• When GET /dog returns any of AngryDog or NiceDog object, the Python client will return a Pet object (without all final_type-specific attributes missing).

Please note that you can also see that the member fields of the Pet and Dog parent object are missing in the AngryDog (cfr. #453).

openapi-generator version

I used OpenAPI generator CLI version 4.0.0-SNAPSHOT:
https://oss.sonatype.org/content/repositories/snapshots/org/openapitools/openapi-generator-cli/4.0.0-SNAPSHOT/openapi-generator-cli-4.0.0-20181210.103357-85.jar

OpenAPI declaration file content or url

See multi-level-inheritance.yaml in the attached zip-file:
multi-level-inheritance.zip

Command line used for generation

java -jar openapi-generator-cli-4.x.jar generate -i ./multi-level-inheritance.yaml -g python -o ./multi-level-inheritance/client/python

Steps to reproduce

1. Generate client code

   See also multi-level-inheritance.sh.

   wget \
       'https://oss.sonatype.org/content/repositories/snapshots/org/openapitools/openapi-generator-cli/4.0.0-SNAPSHOT/openapi-generator-cli-4.0.0-20181210.103357-85.jar' \
       -O 'openapi-generator-cli-4.x.jar'
   rm -rf ./multi-level-inheritance/
   java -jar openapi-generator-cli-4.x.jar generate -i ./multi-level-inheritance.yaml -g python -o ./multi-level-inheritance/client/python
   

2. Start (mocked) server

   python3 -m connexion run --mock=all multi-level-inheritance.yaml
   

3. Run the client test

   (cd multi-level-inheritance/client/python/ && python3)
   

   import openapi_client
   api = openapi_client.DefaultApi()
   pet = api.pet_get()
   print(type(pet))
   print(pet)
   dog = api.dog_get()
   print(type(dog))
   print(dog)

   Output:

   <class 'openapi_client.models.pet.Pet'>
   {'pet_type': 'NiceDog'}
   <class 'openapi_client.models.dog.Dog'>
   {'doggie_thing': 'Playing with piece of wood'}
   

Related issues/PRs

• Better support for composed schema (allOf) #1842
• [WIP] Fix allOf in inline model resolver #1841

Similar issues has been seen with CSHARP and Java:

• [CSHARP] Multi Level inheritance is not building #1068
• [JAVA] Cannot use single discriminator field for two-level inheritance #1113
• [BUG][Python] oneOf (with multi-level inheritance) misses code generation #1663
• [Python] Generated model for component with "allOf" has no attributes #453

Suggest a fix

When we add an addition discriminator in the Dog schema then GET /dog does properly return either an AngryDog or NiceDog object.