Re: Essentiality of Bash

[Goswin von Brederlow <goswin-v-b@web.de>]

Josselin Mouette <joss@debian.org> writes:

> Le samedi 26 juin 2010 à 22:30 +0200, Marc Haber a écrit :
>> On Sat, 26 Jun 2010 15:20:46 +0200, Josselin Mouette <joss@debian.org>
>> wrote:
>> >Furthermore, Iâ??d be interested to know how to fix such a â??shortcomingâ??
>> >in our software. If both A and B depend on each other, A.postinst must
>> >be executed before B.postinst, and vice versa.
>> 
>> That's only one kind of circular dependency, and the one making the
>> problems. When you look at the circular dependencies, for example
>> within the exim4 or the aide packages, you see that the dependencies
>> defined in there aren't _that_ strict.
>
> You could say itâ??s not problematic all the time - thatâ??s the case of
> fcron/exim4, which is only a problem for users installing fcron. But it
> is a real one: if fcron requires exim to be running to work correctly,
> while exim requires fcron to be running to work correctly, youâ??re
> doomed.
>
> In this case, thereâ??s a solution: exim needs (f)cron installed on the
> system, but it doesnâ??t need it to be configured and running. But thereâ??s
> simply no way for dpkg to know that, since the semantics of dependencies
> donâ??t express that order.
>
> For aide, I just donâ??t see the point: itâ??s the simplest, straight
> example of an unjustified 2-packages circular dependency.

It would be nice to introduce a Post-Depends. Post-Depends means the
depended on package needs to be installed but is not needed for
maintainer script. As such the order in which packages are configured is
not restricted.

MfG
        Goswin