import bcrypt error

[carrchr]

>>> import bcrypt
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File ".../venv/lib/python2.7/site-packages/bcrypt/__init__.py", line 23, in <module>
    from bcrypt import _bcrypt
ImportError: dlopen(.../venv/lib/python2.7/site-packages/_cffi_backend.so, 2): Symbol not found: _PyUnicodeUCS2_AsASCIIString
  Referenced from: .../venv/lib/python2.7/site-packages/_cffi_backend.so
  Expected in: flat namespace
 in ...venv/lib/python2.7/site-packages/_cffi_backend.so

This might be an issue with cffi but I figured I would post something here in case anyone has ever run into it. I get the same error when running my project, but I get the same error (as above) when simply activating the virtualenv, running a Python shell and trying as above.
This is 2.7.11 using pyenv and virtualenv on Mac OS X 10.11.4
I have libffi installed via brew
I have tried cleaning, rebuilding, reinstalling, environment variables, and more for the last four hours and can not get past this error

[reaperhulk]

How did you get your Python? System, brew, python.org? Also, what pip version. If < 8.1 try upgrading and then uninstall and reinstall cffi

[carrchr]

pip version 8.1.1
I think the 2.7.11 Python I am using was built from source and is managed via pyenv

Python 2.7.11 (default, Mar  7 2016, 16:47:50) 
[GCC 4.2.1 Compatible Apple LLVM 7.0.2 (clang-700.1.81)] on darwin

Someone from cffi commented this :

CFFI is not correctly installed: the version that it is trying to import was compiled with a different Python than the current one. That's a typical error message for UCS2 versus UCS4 Python versions.

And I was also pointed to pyenv Issue #257 and that it may have something to do with how I built the Python I am using.

[carrchr]

Turns out that it was a "UCS2 versus UCS4 Python versions" problem. Running these commands got my project to build:

$pyenv uninstall 2.7.11
$PYTHON_CONFIGURE_OPTS="--enable-unicode=ucs2" pyenv install 2.7.11

and then reinstalling pip, virtualenv, and pyenv rehash

[carrchr]

Is it worth creating a PR to add some documentation or FAQ/troubleshooting regarding this issue? CFFI did add this to their installation README - http://cffi.readthedocs.io/en/latest/installation.html#linux-and-os-x-ucs2-versus-ucs4

[reaperhulk]

@carrchr Thanks for the information. I'm going to be modifying the build systems to produce both ucs2 and ucs4 wheels for cffi so that users will be able to pull the correct one. Unfortunately users on out of date pip will still pull the wrong one (as pip prior to 8 is unaware of the proper tag), but we can add some information to explain that upgrading to pip8+ will fix the issue.

[reaperhulk]

A UCS4 wheel is now available so this issue should be resolved for future users on pip8+