Bug#838997: lintian: checks/init.d: Check for initscripts that source /lib/lsb/init-functions without declaring the corresponding dependency on lsb-base (>= 3.0-6).

[Andreas Henriksson <andreas@fatal.se>]

Hello Chris,

On Tue, Nov 08, 2016 at 06:56:10PM +0000, Chris Lamb wrote:
> Hi Andreas,
> 
> > Simply *why* is this error added?
> 
> I added this Lintian check after #838966 was filed against one of my
> packages.
[...]

Thanks for providing this background info.

Though I have to say this only makes me more certain we're heading down
the wrong path here. Consider the case when someone has bind-mounted
enough bits into their chroot that invoke-rc.d starts systemctl
instead of directly invoking the init script. What about upstart (which
is still supported in invoke-rc.d even though I hear upstart is no more)?
And open-rc? And ... ?

I'm hope we agree that because your package ships an init script (|| \
systemd unit || ...) you should not start depending on lsb-base &&
systemd && ... (in other words every init system?! Will it even work
to run systemctl in the chroot talking to systemd outside the chroot
starting things inside the chroot? I'd guess no.)

I'm still hoping we can solve this in one generic place. Without having
thought it through I feel like pointing the finger towards
init-system-helpers (invoke-rc.d and update-rc.d). I would think that
when you run an init-less (aka *buildd*) chroot you would also
have a policy-rc.d rule that disallows running of init-scripts etc. via
invoke-rc.d (and update-rc.d).
Maybe we could even automate that by having the *-rc.d tools auto-detect
we don't have an init system in the chroot and treat that as if a
policy-rc.d rule was in place.
(Someone with experience on how buildd setups and policy-rc.d actually
works would be welcome to hear from here.)

I'm sure there are a bunch of trivial init scripts that will work to
start in a init-less chroot, but I would think it can't be a generally
supportable concept. Likely if you skip the init system you should start
whatever you want to run directly.

Ideas and/or comments welcome.

Regards,
Andreas Henriksson

PS. sorry for both being pessimistic and incapable of writing short
mails.