[PYTHON] Generated python server cannot import controller

Description

Some generated controller names are inconsistent between usage in import statements, and the name of the file.

Swagger-codegen version

2.4.0-SNAPSHOT

Swagger declaration file content or url

swagger: '2.0'
info:
  title: bad tag
  description: blah
  version: '0.0'
tags:
  - name: ABCD 1234
    description: blah
paths:
  /something:
    get:
      tags:
        - ABCD 1234
      responses:
        '200':
          description: Successful

Command line used for generation

java -jar swagger-codegen-cli.jar generate \
  -i tag.yaml \
  -l python-flask \
  -o tag/ \
  -s

Steps to reproduce

After running code generation, attempt to start the python server: python3 -m swagger_server. This throws an exception.

Related issues/PRs

This seems similar to issue #7357.

Suggest a fix/enhancement

It seems there is inconsistent name mangling. The module being imported is named abcd_1234_controller, whereas the file is named abcd1234_controller.py.

Python server output

$ python3 -m swagger_server
Failed to add operation for GET /something
Traceback (most recent call last):
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/apis/abstract.py", line 242, in add_paths
    self.add_operation(method, path, endpoint, path_parameters)
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/apis/abstract.py", line 195, in add_operation
    pythonic_params=self.pythonic_params)
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/operation.py", line 215, in __init__
    resolution = resolver.resolve(self)
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/resolver.py", line 40, in resolve
    return Resolution(self.resolve_function_from_operation_id(operation_id), operation_id)
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/resolver.py", line 65, in resolve_function_from_operation_id
    raise ResolverError(msg, sys.exc_info())
connexion.exceptions.ResolverError: <ResolverError: Cannot resolve operationId "swagger_server.controllers.abcd_1234_controller.something_get"! Import error was "No module named 'swagger_server.controllers.abcd_1234_controller'">

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.5/runpy.py", line 184, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.5/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/ethan/Dev/bad-swagger/tag/swagger_server/__main__.py", line 16, in <module>
    main()
  File "/home/ethan/Dev/bad-swagger/tag/swagger_server/__main__.py", line 11, in main
    app.add_api('swagger.yaml', arguments={'title': 'bad tag'})
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/apps/flask_app.py", line 54, in add_api
    api = super(FlaskApp, self).add_api(specification, **kwargs)
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/apps/abstract.py", line 159, in add_api
    options=api_options.as_dict())
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/apis/abstract.py", line 131, in __init__
    self.add_paths()
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/apis/abstract.py", line 249, in add_paths
    self._handle_add_operation_error(path, method, err.exc_info)
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/apis/abstract.py", line 263, in _handle_add_operation_error
    six.reraise(*exc_info)
  File "/home/ethan/.local/lib/python3.5/site-packages/six.py", line 693, in reraise
    raise value
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/resolver.py", line 62, in resolve_function_from_operation_id
    return self.function_resolver(operation_id)
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/utils.py", line 46, in get_function_from_name
    raise last_import_error
  File "/home/ethan/.local/lib/python3.5/site-packages/connexion/utils.py", line 34, in get_function_from_name
    module = importlib.import_module(module_name)
  File "/usr/lib/python3.5/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 986, in _gcd_import
  File "<frozen importlib._bootstrap>", line 969, in _find_and_load
  File "<frozen importlib._bootstrap>", line 956, in _find_and_load_unlocked
ImportError: No module named 'swagger_server.controllers.abcd_1234_controller'

Filesystem:

$ ls swagger_server/controllers
abcd1234_controller.py  __init__.py  __pycache__

Reproduce generation with the supplied Swagger YAML and the python-flask command, then inspect the generated swagger_server/controllers filenames and the operation imports used when running python3 -m swagger_server. Done means the controller module name and filename use consistent mangling so the generated server starts without the reported import error.