Please call insserv on package installation

[Martin Pitt]

Package: insserv
Version: 1.14.0-5.3

Hello,

With the recent changes to make  "init" not essential any more and
drop "initscripts" dependencies from packages it is now possible to
uninstall insserv in Debian sid, or respectively, it would not be
installed any more by debootstrap. This will break any package which
only has a SysV init script without an accompanying systemd unit, and
breaks switching between systemd-sysv and sysvinit-core.

Michael quickly added an insserv dependency to init-system-helpers in [1]
as a quick fix, but we don't actually want to keep this dependency for
an extended time. I now created a proper fallback in update-rc.d
itself [2] that creates start/stop links from Default-{Start,Stop}
headers. However, that only uses [SK]01 priorities as (1) priorities
don't matter in such environments (systemd or chroot without any
init), and (2) we really don't want complex dependency parsing logic
in update-rc.d. Installing sysvinit-core depends on sysv-rc which
depends on insserv.

The only thing missing is that installing insserv (usually via
sysvinit-core) should recompute the link priorities, to get away from
the fixed "01" ones from the update-rc.d fallback. This should be as
simple as calling "insserv" in insserv's postinst, at least on new
installs [ -z "$2" ]. I tested this with a few packages and that
nicely fixes up the priorities.

Thanks for considering,

Martin

[1] https://tracker.debian.org/news/783545
[2] https://anonscm.debian.org/cgit/collab-maint/init-system-helpers.git/commit/?id=ee156d7

-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)