[Bug 1650202] [NEW] issubclass(a_type, union_type) has stopped working

[Gavin Panella]

Public bug reported:

issubclass(a_type, union_type) has stopped working:

In zesty:

  # python3
  Python 3.5.2+ (default, Dec 13 2016, 14:16:35)
  [GCC 6.2.1 20161212] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  >>> import typing
  >>> issubclass(str, typing.Optional[str])
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/usr/lib/python3.5/typing.py", line 770, in __subclasscheck__
      raise TypeError("Unions cannot be used with issubclass().")
  TypeError: Unions cannot be used with issubclass().

In yakkety:

  $ python3
  Python 3.5.2+ (default, Sep 22 2016, 12:18:14)
  [GCC 6.2.0 20160927] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  >>> import typing
  >>> issubclass(str, typing.Optional[str])
  True

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: python3.5 3.5.2-9
ProcVersionSignature: Ubuntu 4.8.0-30.32-generic 4.8.6
Uname: Linux 4.8.0-30-generic x86_64
ApportVersion: 2.20.3-0ubuntu8
Architecture: amd64
Date: Thu Dec 15 09:58:29 2016
ProcEnviron:
 TERM=screen.xterm-256color
 PATH=(custom, no user)
SourcePackage: python3.5
UpgradeStatus: No upgrade log present (probably fresh install)

** Affects: python3.5 (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug zesty

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https://bugs.launchpad.net/bugs/1650202

Title:
  issubclass(a_type, union_type) has stopped working

Status in python3.5 package in Ubuntu:
  New

Bug description:
  issubclass(a_type, union_type) has stopped working:

  In zesty:

    # python3
    Python 3.5.2+ (default, Dec 13 2016, 14:16:35)
    [GCC 6.2.1 20161212] on linux
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import typing
    >>> issubclass(str, typing.Optional[str])
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/usr/lib/python3.5/typing.py", line 770, in __subclasscheck__
        raise TypeError("Unions cannot be used with issubclass().")
    TypeError: Unions cannot be used with issubclass().

  In yakkety:

    $ python3
    Python 3.5.2+ (default, Sep 22 2016, 12:18:14)
    [GCC 6.2.0 20160927] on linux
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import typing
    >>> issubclass(str, typing.Optional[str])
    True

  ProblemType: Bug
  DistroRelease: Ubuntu 17.04
  Package: python3.5 3.5.2-9
  ProcVersionSignature: Ubuntu 4.8.0-30.32-generic 4.8.6
  Uname: Linux 4.8.0-30-generic x86_64
  ApportVersion: 2.20.3-0ubuntu8
  Architecture: amd64
  Date: Thu Dec 15 09:58:29 2016
  ProcEnviron:
   TERM=screen.xterm-256color
   PATH=(custom, no user)
  SourcePackage: python3.5
  UpgradeStatus: No upgrade log present (probably fresh install)

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