[BUG][PYTHON] Generator creates Enums with duplicate attributes

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

Generator creates Enums with duplicate attributes

openapi-generator version

openapi-generator v7.8.0

OpenAPI declaration file content or url

{
  "openapi": "3.1.0",
  "info": {
    "title": "FastAPI",
    "version": "0.1.0"
  },
  "paths": {
    "/status": {
      "get": {
        "summary": "Get Status",
        "operationId": "get_status_status_get",
        "parameters": [
          {
            "name": "Status",
            "in": "query",
            "required": true,
            "schema": {
              "$ref": "#/components/schemas/StatusEnum"
            }
          }
        ],
        "responses": {
          "200": {
            "description": "Successful Response",
            "content": {
              "application/json": {
                "schema": {}
              }
            }
          },
          "422": {
            "description": "Validation Error",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/HTTPValidationError"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "HTTPValidationError": {
        "properties": {
          "detail": {
            "items": {
              "$ref": "#/components/schemas/ValidationError"
            },
            "type": "array",
            "title": "Detail"
          }
        },
        "type": "object",
        "title": "HTTPValidationError"
      },
      "StatusEnum": {
        "type": "string",
        "enum": [
          "ACTIVE",
          "active"
        ],
        "title": "StatusEnum"
      },
      "ValidationError": {
        "properties": {
          "loc": {
            "items": {
              "anyOf": [
                {
                  "type": "string"
                },
                {
                  "type": "integer"
                }
              ]
            },
            "type": "array",
            "title": "Location"
          },
          "msg": {
            "type": "string",
            "title": "Message"
          },
          "type": {
            "type": "string",
            "title": "Error Type"
          }
        },
        "type": "object",
        "required": [
          "loc",
          "msg",
          "type"
        ],
        "title": "ValidationError"
      }
    }
  }
}

where the important part is:

"StatusEnum": {
  "type": "string",
  "enum": [
    "ACTIVE",
    "active"
  ],
  "title": "StatusEnum"
}

Generation Details

openapi-generator generate -i openapi_example.json -g python --package-name example -o .

Steps to reproduce

Create a simple FastAPI:

import json
from enum import Enum

from fastapi import FastAPI, APIRouter

app = FastAPI()
router = APIRouter()

class StatusEnum(str, Enum):
    ACTIVE = "ACTIVE"
    ENUM_ACTIVE = "active"

@router.get("/status")
async def get_status(Status: StatusEnum):
    return {"status": Status.value}

def write_openap_spec(app):

    openapi_schema = app.openapi()

    with open("openapi_example.json", "w") as f:
        json.dump(openapi_schema, f, indent=2)

if __name__ == "__main__":
    app.include_router(router)
    write_openap_spec(app)

and generate the PythonClient with the generator, resulting in the following Enum in Python:

# coding: utf-8

"""
    FastAPI

    No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)

    The version of the OpenAPI document: 0.1.0
    Generated by OpenAPI Generator (https://openapi-generator.tech)

    Do not edit the class manually.
"""  # noqa: E501


from __future__ import annotations
import json
from enum import Enum
from typing_extensions import Self


class StatusEnum(str, Enum):
    """
    StatusEnum
    """

    """
    allowed enum values
    """
    ACTIVE = 'ACTIVE'
    ACTIVE = 'active'

    @classmethod
    def from_json(cls, json_str: str) -> Self:
        """Create an instance of StatusEnum from a JSON string"""
        return cls(json.loads(json_str))

where we retrieve the duplicate attribute ACTIVE in the StatusEnum.

Related issues/PRs

None

Suggest a fix

Add

@Setter protected boolean allEnumValuesUpperCase = true;

in AbstractPythonCodegen.java and the regarding logic to handle the case where enums shouldn't be capitalized.

Start with AbstractPythonCodegen.java and reproduce the issue using the supplied OpenAPI declaration and openapi-generator generate -i openapi_example.json -g python --package-name example -o . command. Trace how the ACTIVE and active enum values become Python attributes. Done means the generated StatusEnum no longer contains duplicate attribute names while preserving both enum values.