Re: Should we allow packages to depend on packages with lower priority values?
On Mon, 8 Dec 2003, Marc Haber wrote:
> Policy 2.5 says that packages must not depend on packages with lower
> priority values. From what I tried to research, that rule is meant to
> allow CD builders to build "Debian foo standard" CDs containing
> required, important and standard packages, guaranteed that all
> dependencies are satisfied just from choosing from the Priority.
Not only that, combined with the rule saying "packages which conflicts
with optional or higher should be extra", people should be able to
forget completely about extra packages when choosing packages without
having unmet dependencies.
> This must be residue from the times when CD building tools didn't
> follow dependency chains. Today, it is trivial to build
> dependency-complete "Debian standard" CDs by including required,
> important and standard packages and following down the dependency
> chain. apt-get is a tool that can solve this, and at least the old CD
> building tools used apt-get to resolve the dependencies. This has been
> the case at least since slink when I joined the Debian user community.
>
> This being said, I'd like to point out a problem that this policy
> requirement poses.
>
> Let A and B both be packages that provide virtual package C. A is the
> default C in Debian, and is therefore Priority: important. A depends
> on E and F, which must be Priority: important as well, as required by
> current Policy.
>
> Now let's look at a system where the local administrator has decided
> to use B instead of A. Since E and F are Priority: important, dselect
> happily proceeds to install E and F on the system, even if they are
> not needed since the system in question uses B instead of A.
So you want postfix but not the dependencies for exim?
Just tell dselect to uninstall E and F. Where is the problem?
You will only have to do this once and dselect will remember that you
don't want E and F installed (unless they are required later by another
package).
The dependency rule is still useful for those who trust Debian having
good defaults and want to forget about extra packages.
The deborphan package provides a much better way of getting rid of
unwanted packages which are installed only because of dependencies,
have not you tried it?
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