[BUG][Python] python-fastapi 7.9.0 generates wrong imports

[al3ad]

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

An import is generated that does not exist.

openapi-generator version

7.9.0

OpenAPI declaration file content or url

The code for the yaml spec can be found here: https://github.com/bbc/tams/tree/main/api

Generation Details

This is a snippet of the file it generates with the relevant to the issue imports:

from pydantic import ConfigDict, Field
from openapi_server.models.object import object
try:
    from typing import Self
except ImportError:
    from typing_extensions import Self

class MediaBucketObjectStore(object):
    ...

The issue is the imported object, which doesn't exist.

I believe the generated file should be this:

from pydantic import ConfigDict, Field, BaseModel
try:
    from typing import Self
except ImportError:
    from typing_extensions import Self

class MediaBucketObjectStore(BaseModel):
    ...

Steps to reproduce

build-server-local-fastapi:
	docker run --user ${USER}:${GROUP} --rm \
                   -v ${PWD}:/local openapitools/openapi-generator-cli:v${GEN_VER} generate \
				   --additional-properties=apiNameSuffix=controller_impl \
                   -t /local/.templates/7.9.0/python_fastapi/.openapi-generator-server/ \
                   -i /local/openapi.yaml \
                   -g python-fastapi \
                   -o /local/python_fastapi/

[claudiadpp]

Hi, I have the same problem.

summary

When generating Python FastAPI server code with OpenAPI Generator, the generated models import object from a non-existent module and inherit from object

openapi-generator version

v7.15.0
Generator: python-fastapi

description
For the API specification

    Configuration:
      type: object
      additionalProperties: true
      properties:
        acceptedOutputModes:
          type: array
          maxItems: 100
          description: "Accepted output modes"
          items:
            type: string
            maxLength: 100
            example: "text"
            enum:
              - "text"
              - "text/plain"

The generated code is

from pydantic import ConfigDict, Field, field_validator
from <module_name>.models.object import object

class Configuration(object):
    ...

The generated could should be

from pydantic import ConfigDict, Field, field_validator, BaseModel

class Configuration(BaseModel):
    ...

where BaseModel is added to pydantic import and the object import is removed.

[Shaun-3adesign]

The spec has changed so the object "MediaBucketObjectStore" this issue originally referenced is no longer an issue but the bug still exists, and can be seen in the HTTPRequest model of the same api