[gentoo-user] ujson in a virtualenv explodes with undefined symbol: Buffer_AppendShortHexUnchecked

[Daniel Quinn]

I'm hoping someone can explain what's going on to me here.

I had a perfectly reasonable dev environment for months, and then one
day, I upgrade ujson in that virtualenv and it explodes with this:

    ImportError:
/home/daniel/.virtualenvs/myvenv/lib/python2.7/site-packages/ujson.so:
undefined symbol: Buffer_AppendShortHexUnchecked

Assuming it was just the update, forced a downgrade from 1.34 to 1.33. 
The error is still there.  In fact, no matter what version I install
now, even to go so far back as 1.4, the same error comes up.

Now, knowing that the error doesn't happen on other machines at these
versions, and knowing that even on this machine it was working fine
until this afternoon, I have to assume that it has to do with the host
system and not the virtualenv.  Indeed, the steps to produce this
problem are:

    virtualenv myvenv
    . myvenv/bin/activate
    pip install ujson
    python -c 'import ujson'

Interestingly, ujson works just fine *outside of a virtualenv*.  As in,
if I install it with `emerge dev-python/ujson` it works just fine.  It's
the existence within a virtualenv that appears to be the problem.  I did
run an update recently that updated dev-python/setuptools, but
downgrading that from 19.2 to 19.1.1 doesn't appear to fix the problem
either.  Also, reinstall virtualenv (just for kicks) didn't fix things.

I'm really at a loss here and I'd like to get some work done today.  Any
suggestions?