Pbuilder: virtual packages

[Gael Varoquaux]

Hi,

I am one of the upstream developpers of mayavi2 and of the enthought
tools suite. We hae just had a major release of the enthought tools suite
and I wanted to try packaging it for Debian in a more modular way then it
is currently packaged (4 packages: python-enthought-traits,
python-enthought-traits-ui, python-enthought-chaco2 and mayavi2). As I
didn't want to put the burden on the Debian developpers to create the
additionnal packages, and as I run Ubuntu, I decided to create these
packages myself, and dto hand them over to the DDs once I had working
versions, for them to imrpove and maintain.

My knowledge of Debian package is very small, and thus I ran into a
problem quite quickly. The mayavi2 package needs python-numpy and
python-vtk when building (it generates wrappers for the entire VTK
library and reuses some of the numpy build scripts). However it seems
that these do not install well in the sandbox used to build Debian
packages, as can be seen on
http://launchpadlibrarian.net/16510892/buildlog_ubuntu-hardy-i386.mayavi2_3.0.0-1~ppa1_FAILEDTOBUILD.txt.gz
. Andrea Colangelo pointed me towards pbuilder and I was able to
reproduce the problem on my box, and it boils down to this:

"""
The following packages have unmet dependencies:
  pbuilder-satisfydepends-dummy: Depends: python-numpy which is a virtual
package.
                                 Depends: python-vtk which is a virtual
package.
Resolving dependencies...
"""

So my question is: how do I get python-vtk and python-numpy as build
dependencies for my package? What is the right line in the debian/control
file?

Sorry for asking what is probably a trivial question on debian packaging.
Packaging is certainly not my core business.

Cheers,

Gaël