[Pkg-utopia-maintainers] Bug#846381: avahi-daemon: cups frequently forgets about all printers untils restarting avahi-daemon

[Helmut Grohne]

Package: avahi-daemon
Version: 0.6.31-5
Control: affects -1 cups-daemon

Since Debian jessie, cups uses avahi to broadcast its printers to the
local network. I have a jessie cups with a few printers and publish them
via avahi. Now I am seeing a little weird behaviour on client systems:
After booting their cups daemons know about the broadcasted printers,
but after some time (usually a few times a day) they forget. I have no
clue what causes the client cups to forget about all network printers,
but after issuing "service avahi-daemon restart" on the client machine,
all the printers are back.  Restarting something else (such as cups)
doesn't get me the printers back instead. This lets me conclude that
avahi-daemon somehow is the cause. I am observing this with both jessie
and unstable client systems, so stretch is affected. The
avahi-daemon.conf is pretty much the default with the exception of
setting disable-publishing=yes on all client systems. I have no idea how
to reliably trigger this bug (beyond waiting a day). Before and after
restarting avahi-daemon, the output of "avahi-browse -at" looks no
different (i.e. printers always show up there).

I understand that this bug description is quite vague. Still, it is
fairly annoying and as it happens on multiple systems some of which are
pretty close to defaults, I believe still believe it to be a bug. I
already spent considerable time trying to diagnose it and intend to do
further diagnosis if someone can provide hints as to what to check. It
might even be a cups bug. Please reassign as appropriate.

Thanks in advance

Helmut