dpkg hooks

[William Pursell]

Originally, I was planning to post this question to one of the
Debian lists, but the second part of the question is more
appropriate here, so I thought I would just start here.

I often find myself removing a package and then deleting
all of my cache files, but I have a tendency to forget
to delete the cache files until a configure invocation
noticeably misbehaves.

At first, I thought that I wanted some sort of hook
into dpkg/aptitude/apt-get/synaptic/etc to automatically
remove all of my cache files when a package is deleted.
I'm perfectly happy making dpkg a shell function that
does the delete for me, but was hoping for more elegant
suggestions.

Then I realized that what I really want is a hook to
update all the cache files.  Clearly, updating the
cache is hard in general, but for simple packages,
it would be very easy for the package's install and
post-install scripts to do, for sufficiently broad
definitions of "very easy".  However, that puts
all the work on the package maintainer.  All of
the information is available in the database, and
could be done automatically.  Does any such mechanism
already exist?  Is there a way to update a cache file
easily and quickly?