Re: Getting rid of circular dependencies, stage 6

[Frank Küster <frank@debian.org>]

Don Armstrong <don@debian.org> wrote:

> On Tue, 24 Oct 2006, Petter Reinholdtsen wrote:
>> [Ian Jackson]
>> > The only argument I've heard against circular dependencies as a
>> > general rule is that they can trigger a particularly stupid (and
>> > probably not very hard to fix) bug in apt,
>> 
>> You seem to have missed the argument that packages with circular
>> dependencies are impossible to install and configure in the correct
>> (dependency) order, and thus will end up being installed and
>> configured in a nondeterministic order instead. It is documented
>> that dpkg try its best to find a sensible order for the packages,
>> but it is bound to fail one way or another if two packages really do
>> need each other to be configured before they are configured.
>
> Packages which have circular dependencies and depend on the other
> package being configured are buggy; at most they can depend on the
> other package being unpacked. Since there is no way to specify this
> kind of dependency, Depends: is as close as you can get.

It seems to me that the solution in such situation shouldn't be a
circular dependency with its "nondeterministic" behavior, but instead to
separate one of the packages into two.  For example if package b needs
package a unpacked, but not configured, separate package a in a-data and
a-therest, where a-data provides all that package b needs: Now b can
depend on a-data, and a-therest can depend on b.

Regards, Frank
-- 
Dr. Frank Küster
Single Molecule Spectroscopy, Protein Folding @ Inst. f. Biochemie, Univ. Zürich
Debian Developer (teTeX/TeXLive)