trying to set up virtualenv gives error 'cannot import name _remove_dead_weakref' while installing vatic

Question

Im trying to install vatic, and one requirement is to run 'virtualenv .env' from the vatic workspace. When I run this, I get that ~/anaconda2/lib/python2.7/weakref.py has an error 'cannot import name_remove_dead_weakref.

virtualenv .env
New python executable in /home/tyler/vatic_ws/.env/bin/python
Installing setuptools, pip, wheel...
    Complete output from command /home/tyler/vatic_ws/.env/bin/python - setuptools pip wheel:
      Traceback (most recent call last):
      File "<stdin>", line 7, in <module>
      File "/home/tyler/anaconda2/lib/python2.7/site-packages/virtualenv_support/pip-9.0.1-py2.py3-none-any.whl/pip/__init__.py", line 5, in <module>
      File "/home/tyler/anaconda2/lib/python2.7/logging/__init__.py", line 26, in <module>
        import sys, os, time, cStringIO, traceback, warnings, weakref, collections
      File "/home/tyler/anaconda2/lib/python2.7/weakref.py", line 14, in <module>
        from _weakref import (
    ImportError: cannot import name _remove_dead_weakref

But when I try to run a python script of my own with

from _weakref import _remove_dead_weakref

I dont get an error. Why cant I replicate the error, and how do I fix it?

Answer 1

Brandon Rhodes has solved this problem.
The relevant part of the description:

# How does the Anaconda Python binary usually wind up linking to their
# own "libpython2.7.so" instead of Ubuntu's?  By, it turns out, having a
# relative RPATH - that only works if their Python binary is sitting
# right next to the "lib" directory containing their libpython:
#
# $ readelf -d anaconda/bin/python2.7 | grep RPATH
# 0x0000000f (RPATH)                      Library rpath: [$ORIGIN/../lib]
#
# This situation obviously does not pertain in a new virtualenv since it
# only copies in a minimal ".../lib/pythonX.Y" directory, not any shared
# libraries into "../lib" itself.  Hence the linker falls back to
# discovering and linking to the system "libpythonX.Y.so".

You need to run his script. I'll duplicate the script here in case it disappears.

if ! python -c 'import virtualenv' 2>/dev/null
then
    echo 'Error: virtualenv is not available to the current "python" binary'
    exit 1
fi

venv=$(python -c 'import virtualenv; print(virtualenv.__file__)')
venv=${venv%c}

if grep -q 'Added by Brandon' $venv
then
    echo 'Exiting: virtualenv.py has already been fixed'
    exit 0
fi

echo 'Editing virtualenv.py'

sed -i -f - $venv <<'EOF'
/^    stdlib_dirs = /i\
\
    # Added by Brandon's ",fix-virtualenv" script to copy the Anaconda\
    # libpython libraries into the new environment as well:\
    outer_lib_dir = os.path.dirname(lib_dir)\
    conda_lib_dir = os.path.dirname(os.path.dirname(os.__file__))\
    for fn in os.listdir(conda_lib_dir):\
        if fn.startswith('libpython'):\
            copyfile(join(conda_lib_dir, fn), join(outer_lib_dir, fn), symlink)\
EOF