Message9548

Flask App used to work with 2.7-b3, but now it doesn't with 2.7-b4

The issue can be reproduced from the shell just importing flask:

In 2.7-b3: No errors:

$ java -jar jython-standalone-2.7-b3.jar
Jython 2.7b3 (default:e81256215fb0, Aug 4 2014, 02:39:51)
[OpenJDK 64-Bit Server VM (Oracle Corporation)] on java1.7.0_75
Type "help", "copyright", "credits" or "license" for more information.
>>> import flask
>>> quit()

In 2.7-b4: Errors:

$ java -jar jython-standalone-2.7-b4.jar
Jython 2.7b4 (default:3672e624962a, Feb 13 2015, 04:59:14)
[OpenJDK 64-Bit Server VM (Oracle Corporation)] on java1.7.0_75
Type "help", "copyright", "credits" or "license" for more information.
>>> import flask
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "flask/__init__.py", line 21, in <module>
    from .app import Flask, Request, Response
  File "flask/app.py", line 24, in <module>
    from .helpers import _PackageBoundObject, url_for, get_flashed_messages, \
  File "flask/helpers.py", line 40, in <module>
    from .globals import session, _request_ctx_stack, _app_ctx_stack, \
  File "flask/globals.py", line 14, in <module>
    from werkzeug.local import LocalStack, LocalProxy
  File "werkzeug/local.py", line 249, in <module>
    @implements_bool
TypeError: Error when calling the metaclass bases
    __dict__ slot disallowed: we already got one
>>>