Re: Proper dependency on essential package (dpkg) for preinst

[Sven Joachim <svenjoac@gmx.de>]

Am 28.05.2009 um 19:34 schrieb Helge Kreutzmann:

> I recently got an RC bug (#530653) which turned out to be a change 
> in dpkg's update-alternative (the string and output channel of an 
> error message was changed which is used in the preinst). So I 
> prepared a new package, but this of course will only work with the
> dpkg in unstable (not the one currently in testing nor (old)stable). 
>
> To allow (partial) updates I think the proper way would be to depend
> on dpkg (>= 1.15.0) until Squeeze is released. 
>
> I read debian-policy and I think I'm right. But given this is in the
> preinst I would like to confirm that in this case not one of the other
> options (Pre-Depends, Conflicts, Breaks) is more suitable.

I don't know why this preinst script is necessary, but if you need to
insure that the new update-alternatives script is run in it, you have to
use Pre-Depends rather than Depends.  See Policy § 7.2.

AFAIK on the buildds packages are unpacked by the host system's dpkg
which will be the stable version, so a Pre-Dependency on an unstable
dpkg is frowned upon.

Sven