Recommends by Default

Emmet Hikory persia at
Fri Aug 15 17:24:27 BST 2008

    As you may have heard, Ubuntu is installing Recommends by default
in intrepid.  As a result, the current disk images (and expected
installs) include a large number of packages previously not present in
UbuntuStudio.  While many of these packages are useful, some are less
so, and in some cases, additional changes are required.

    Cory and I spent about an hour and a half looking at the list of
new packages recently, and found two issues which seemed like they
would benefit from immediate attention: that the current install
appers to include most of KDE and that it includes also
usplash-theme-ubuntu.  These are different classes of problem, but
serve to illustrate some of the work that can be done to help bring
the package selection back under control.

    In the case of KDE, it appears that rosegarden depends on
kdebase-bin, khelpcenter, and has a preferred dependency on konqueror
as a browser.  While this is perfectly normal for a KDE application,
with Recommends-by-default, these applications suddenly begin to
include much more of KDE than was true previously.  As these packages
are part of the core of KDE, it is presumed that Kubuntu relies on the
relationships in order to ensure the desired desktop.  It is presumed
to be rather difficult to fix this, and so rosegarden has been dropped
from the ubuntustudio-audio base install (alternate applications
include, depending on your requirements, audacity, seq24, MuSE,
ardour, and possibly others).  There may be other applications with
similar large independent dependency/recommends trees that ought be
reviewed to see if there is an alternate program for which the
dependencies and recommendations more closely match that which is
generally installed in Ubuntu Studio: these should be found, and
discussed with the team as possible candidates for removal.

    In the case of usplash-themes-ubuntu, it appears that usplash
Recommends: usplash-theme-ubuntu | usplash-theme.  As
usplash-theme-ubuntustudio doesn't provide usplash-theme, usplash will
always install usplash-theme-ubuntu.  usplash-theme-ubuntustudio has
now been modified to include the necessary Provides:, and so
usplash-theme-ubuntu will no longer be required.  As with the case
above, there are surely more packages where the recommends include
some Ubuntu-specific feature, and some change may be required to
ubuntustudio packages to work around it.  One known example is gdm
(1).  There are surely more: these should be found, and fixed.

    Some tools that might help you in your quest to find the growth:
firstly, from a hardy install, configure intrepid sources.list, and
run `apt-get --fix-policy --install-recommends dist-upgrade`.  The set
of NEW packages to install may include things that surprise you, and
it is these that could be reduced.  You may also find that the output
of e.g. `apt-rdepends --show=Depends,Recommends ubuntustudio-audio`
provides some intersting information: be warned this generates a *lot*
of output, so be prepared for a bit of a search.

    If you have a candidate you know to be unexpected, `apt-cache
rdepends <pkgname>` will show you want depends upon it (which might
help you to understand how it is getting installed).  `apt-cache show
<pkgname>` can help show a specific package, so one may determine if
the dependency indicated by rdepends is a Depends: or Recommends:, or
otherwise give you information about the package.  There's lots to be
done: if you're up for fixing things, please do so.  If you're not,
please file bugs indicating what change would make sense.  It is
generally worth considering how these changes will affect other
flavours as well: it may be that a given change would interfere with
another flavour, and a more complex solution found (as in the case of
usplash), or the package dropped (as in the case of rosegarden).  Best
of luck, and please ask in #ubuntustudio-devel if you seek guidance in
working on this effort.



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