Adding attributes to the control file / access to the status file
To ease the packaging of python modules, extensions and applications,
some extra meta information should be added to packages building
python modules, extensions and applications. This information says
something about for which python versions the package should be built
and which python versions can be used with this package. The new
metadata can be kept either in a separate db/file or as a user
attribute in the control file. Having a separate db doesn't allow to
work with the existing packaging tools, and you have to look at the
content of packages when you want to know something over the package.
The added attribute moves this information in reach of the packaging
tools. Accessing this kind of information in the postinst/prerm is
possible, but comes for a price: speed of dpkg. This can be
accelerated by directly accessing the status file or using tools like
grep-dctrl to access the status file. Steve Langasek pointed out that
the status file is internal do dpkg and may change without notice. Is
it safe to assume that dpkg will either provide a backward compatible
way to access this data, and/or that another method to access this
data will be provided? The task in this case is to find a subset of
packages with the new meta information, when doing an update to the
another python version.
Matthias
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