Cryptography: Handle having the "enum" package installed better

[MortenEriksen]

After upgrading the cryptography module with pip, the Python OpenSSL wrapper doesn't work properly any more on my system because an import from cryptography fails. I could recreate this in a naked Python REPL, so it doesn't look like it has anything to do with OpenSSL per se?:

>>> from cryptography import x509
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/cryptography/x509/__init__.py", line 8, in <module>
    from cryptography.x509.base import (
  File "/usr/local/lib/python2.7/dist-packages/cryptography/x509/base.py", line 16, in <module>
    from cryptography.x509.extensions import Extension, ExtensionType
  File "/usr/local/lib/python2.7/dist-packages/cryptography/x509/extensions.py", line 24, in <module>
    from cryptography.x509.general_name import GeneralName, IPAddress, OtherName
  File "/usr/local/lib/python2.7/dist-packages/cryptography/x509/general_name.py", line 18, in <module>
    from cryptography.x509.name import Name
  File "/usr/local/lib/python2.7/dist-packages/cryptography/x509/name.py", line 28, in <module>
    _ASN1_TYPE_TO_ENUM = dict((i.value, i) for i in _ASN1Type)
TypeError: 'type' object is not iterable
>>> 
>>> import cryptography
>>> cryptography.__version__
'2.1.3'
>>> 

[MortenEriksen]

Found out why it happened. My system had this enum package installed: https://pypi.python.org/pypi/enum

But it looks like the cryptography code needs the Python 3 enum, or its backport for 2.7: https://pypi.python.org/pypi/enum34

[alex]

Yeah that's right. Unfortunately I don't think there's a way around this.

[MortenEriksen]

No problem for me, easy enough to update to enum34. For other users who may run into the same problem, I suppose a version check and abort on detecting a non-conforming version would be a nice way to handle it.

[xiapeng0701]

@MortenEriksen
Thanks your solution.
"pip install enum34" could fixed my question.
you are so nice.

[alex]

The ecosystem appears to have resolved this issue, so we're not going to add an explicit workaround.