Vim on Ubuntu 14.04 uses a funny python path, python can't import _io among other modules

Question

All of a sudden (probably after a package update or something) vim stopped working with YouCompleteMe and throws:

Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/lib/python2.7/io.py", line 51, in <module>
    import _io
ImportError: No module named _io

(this also happens when I try to import io from inside vim using :python import io).

I've been battling this for the last couple of hours, no idea what the problem is, reinstalled python and vim several times, both from source and from aptitude, no difference. I've noticed that python inside vim uses a funny path compared to from the command line:

~$ python
Python 2.7.6 (default, Jun 22 2015, 17:58:13) 
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys; print sys.path
['', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-x86_64-linux-gnu', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/PILcompat', '/usr/lib/python2.7/dist-packages/gtk-2.0', '/usr/lib/pymodules/python2.7', '/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode']
>>> 

And from vim:

:python import sys; print sys.path
['/usr/lib/python27.zip', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-linux2', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '
/usr/lib/python2.7/lib-dynload', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/PILcompat', '/usr/lib/python2.7/dist-pa
ckages/gtk-2.0', '/usr/lib/pymodules/python2.7', '/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode', '_vim_path_']

I am not usingvirtualenv (I've noticed some people running into this with virtualenv set up).

Also must point out that Python works perfectly fine from the command line and I can happily import io when launching the interpreter and that this happens with both vim 8 compiled from source and vim-nox from aptitude.

Is it an issue with how python sees its path inside vim? I'm at my wits' end, no idea what to do to fix this.

Answer 1

YouCompleteMe provides an option g:ycm_server_python_interpreter to set a specific interpreter.

Just add let g:ycm_server_python_interpreter = path/to/your/interpreter in your .vimrc with the path of your favored interpreter.