[BUG][PYTHON] Multiple authentication schemes are used, only want to use one

Created by: phillip-elliott

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
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Description

I have a spec with the following securitySchemes:

"securitySchemes": {
      "APIKeyHeader": {
        "type": "apiKey",
        "name": "API-Key",
        "in": "header"
      },
      "basicAuth": {
        "type": "http",
        "scheme": "basic"
      }
    }

I am applying these schemes globally, indicating that either APIKeyHeader OR basicAuth can be used:

security": [
    {
      "APIKeyHeader": []
    },
    {
      "basicAuth": []
    }
  ],

When using a python client, I do the following:

config = Configuration()
config.host = base_url
config.api_key['API-Key'] = api_key

api_client = ApiClient(configuration=config)
project_api = ProjectsApi(api_client)

I am not providing a username or password. I would expect the python client to ignore the basic auth scheme and just use the apiKey scheme instead. Instead, both are used and all requests are denied (403).

openapi-generator version

4.1.1

OpenAPI declaration file content or url

https://gist.github.com/phillip-elliott/0438a8159f138e1f270a7814b81e65d9

Command line used for generation

openapi-generator generate -i openapispec.json -g python

Suggest a fix

The python client's Configuration class has a method named get_basic_auth_token. This method could return None if username and password are both set to None. If it returns None, then I believe the basic auth header will not be added to the requests (see ApiClient.update_params_for_auth).