bzr: ERROR: No module named expat; use SimpleXMLTreeBuilder instead

[Stephen J. Turnbull]

On Fri, Mar 23, 2012 at 11:58 AM, Erik de Castro Lopo
<mle+tools at mega-nerd.com> wrote:
> Martin Packman wrote:
>
>> Make sure you have the package 'python' installed, not just
>> 'python-minimal'.
>
> I have:
>
>    $ dpkg -l | grep python2.7
>    ii  libpython2.7        2.7.3~rc2-1   Shared Python runtime library (version 2.7)

Uh, that's why they call it the "bleeding edge".  This has the
super-paranoid "improved"
randomized-hash dictionaries in it.

>    $ python -c "import xml.parsers.expat"
>    [...]
>    ImportError: /usr/lib/python2.7/lib-dynload/pyexpat.so: undefined symbol: XML_SetHashSalt

You need a blood transfusion for your expat, I think.  It appears that
your expat is too old to have the corresponding change in expat.
See the "Hash collision security issue (now public)" thread on
python-dev (maybe tl;dr :-P):
http://mail.python.org/pipermail/python-dev/2011-December/115116.html

Or you can just wait for Debian.