Full dpkg error is :
{{{
Selecting previously deselected package python2.4-matplotlib.
Unpacking python2.4-matplotlib (from .../python2.4-matplotlib_0.82-5ubuntu1_i386.deb) ...
dpkg: error processing /var/cache/apt/archives/python2.4-matplotlib_0.82-5ubuntu1_i386.deb (--unpack):
trying to overwrite `/usr/lib/python2.4/site-packages/pytz/__init__.py', which is also in package python2.4-tz
dpkg-deb: subprocess paste killed by signal (Broken pipe)
Selecting previously deselected package python-matplotlib.
Unpacking python-matplotlib (from .../python-matplotlib_0.82-5ubuntu1_all.deb) ...
Errors were encountered while processing:
/var/cache/apt/archives/python2.4-matplotlib_0.82-5ubuntu1_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
}}}
I wonder what is different in built-in pytz.
I'm getting the same problem.
I've checked out matplotlib, and in setup.py it tests for existence of pytz and dateutil in the system, and won't install them unless the user doesn't have them already. So I suspect that using python-tz as a build dependency and runtime dependency might fix the issue.
We're considering using matplotlib in a project, and this problem is affecting us, since zope3 depends on python-tz, and matplotlib currently breaks with python-tz installed, so we can't have both zope3 and matplotlib available at the same time.