[BUG][Python] Composed Model serialization bug (anyOf)

[gbvanrenswoude]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

When generating a client from an OAS with a composed model situation (like https://gist.github.com/gbvanrenswoude/1143a79dd6f150931c5c00826f6454a2) the resulting EventModel class does contain wrong information about the possible Models being used:

openapi_client/model/event_model.py

    def openapi_types():
        """
        This must be a method because a model may have properties that are
        of type self, this must run after the class is loaded

        Returns
            openapi_types (dict): The key is attribute name
                and the value is attribute type.
        """
        return {
            'event_payload': (bool, date, datetime, dict, float, int, list, str, none_type,),  # noqa: E501
            'correlatie_id': (str,),  # noqa: E501
            'event_title': (str,),  # noqa: E501
        }

Where

'event_payload': (bool, date, datetime, dict, float, int, list, str, none_type,),  # noqa: E501

is wrong. This might indicate a composed model serialization bug caused by the use of anyOf in the OAS.

replicate

In order to replicate the situation, save the linked gist as whoof.json.
The command then used is openapi-generator generate -i whoof.json -g python -o resources/whoof_api_client

openapi-generator version

5.3.0

With 5.2.0 the issue exists too, but results in 'event_payload': (dict,), # noqa: E501.

related issues

This might be related to this PR:

• [Java] Fixes schema class type booleans for composed schemas #10334

[spacether]

An example showing that anyOf transmit/receive serialization/deserialization works is being added in: #10754

When you are using composed payloads (oneOf/anyOf/allOf) definitions

• make sure that the composed schema is defined as a component with the oneOf/anyOf/allOf in its root level
• if one needs to use this as a nested field in an object or array, $ref the component

[gbvanrenswoude]

We succesfully implemented the example being added in #10754. I will close this issue with that. That being said, the less pressing question for the future would be to support model composition in the future in properties. I will leave the example in the issue up and add the changed example below for any folks running into the same / similar issues with model composition.

"components": {
    "schemas": {
      "fixed": {
        "anyOf": [
          {
            "$ref": "#/components/schemas/aaa"
          },
          {
            "$ref": "#/components/schemas/bbb"
          },
          {
            "$ref": "#/components/schemas/ccc"
          },
          {
            "$ref": "#/components/schemas/ddd"
          }
        ]
      },
      "EventModel": {
        "title": "Event Model",
        "required": [
          "aaa",
          "bbb",
          "ccc",
          "event_payload",
        ],
        "type": "object",
        "properties": {
          "event_payload": {
            "$ref": "#/components/schemas/fixed"
          }, 
....

[spacether]

I am working on a new python-experimental generator which will support composition in all Schema locations:

• models (CodegenModel)
• properties/additionalProperties/items (CodegenProperty)
• payload responses (CodegenResponse)
• endpoint parameters (CodegenParameter)