Comment 6 for bug 452090

I can reproduce the problem in a VM:

The dependencies look as following:

Package: sysvinit-utils
Priority: required
Depends: upstart (>= 0.6.3-4)

Package: upstart
Priority: required
Pre-Depends: sysvinit-utils

Because of the pre-depends apt would have to unpack and configure sysinit-utils before upstart, but upstart is a dependency of sysvinit-utils so it can not configure it until upstart is unpacked.

Its actually worse, because both packages are really low in the dependency chain and util-linux (with essential=yes) needs them, apt wants to do a immediate configure on both of them. So even if the Pre-Depends sysvinit-utils becomes
a normal depends apt will still error out unless it is called with "-o Apt::Immediate-Configure=false" (which is in itself dangerous).