[BUG] Python client fails for camelCase multipart/form-data file binary property

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 the Python client code for the OAS YAML spec provided below, there's a mapping error in the generated code for the camelCase property inputFile of binary type:

The code is assigning params['file'][param_name] (param_name = 'input_file'), when it should be params['file'][base_name] (base_name = 'inputFile')

Generated code looks like:

                if (param_location == 'form' and
                        self.openapi_types[param_name] == (file_type,)):
                    params['file'][param_name] = [param_value]
                elif (param_location == 'form' and
                        self.openapi_types[param_name] == ([file_type],)):
                    # param_value is already a list
                    params['file'][param_name] = param_value

It should be:

                if (param_location == 'form' and
                        self.openapi_types[param_name] == (file_type,)):
                    params['file'][base_name] = [param_value]
                elif (param_location == 'form' and
                        self.openapi_types[param_name] == ([file_type],)):
                    # param_value is already a list
                    params['file'][base_name] = param_value

openapi-generator version

5.2.0

OpenAPI declaration file content or URL

openapi: 3.0.1
info:
  title: My API
  version: 0.9.0

paths:
  /uploadFile:
    post:
      operationId: uploadFile
      requestBody:
        content:
          multipart/form-data:
            schema:
              type: object
              properties:
                description:
                  type: string
                inputFile:
                  type: string
                  format: binary
              required:
                - description
                - inputFile
      responses:
        '201':
          description: Created

Generation Details

openapi-generator generate \
  --input-spec minimal-api-spec.yaml \
  --generator-name python \
  --package-name client \
  --output client

Steps to reproduce

1. Generate the Python client code with the command above
2. Verify the generated api_client.py has the wrong mapping for the 'file' params

Generated code looks like:

                if (param_location == 'form' and
                        self.openapi_types[param_name] == (file_type,)):
                    params['file'][param_name] = [param_value]
                elif (param_location == 'form' and
                        self.openapi_types[param_name] == ([file_type],)):
                    # param_value is already a list
                    params['file'][param_name] = param_value

It should be:

                if (param_location == 'form' and
                        self.openapi_types[param_name] == (file_type,)):
                    params['file'][base_name] = [param_value]
                elif (param_location == 'form' and
                        self.openapi_types[param_name] == ([file_type],)):
                    # param_value is already a list
                    params['file'][base_name] = param_value

Related issues/PRs

None

Suggest a fix

Start with minimal-api-spec.yaml and run the documented openapi-generator command for the Python client. Inspect the generated api_client.py multipart file-parameter mapping for the camelCase inputFile property and compare it with the expected output in the issue; done means the generated mapping preserves inputFile for binary form data.