Re: Bug#801065: Section 6.4 - discourage failing install or upgrade when service fails to start

[Henrique de Moraes Holschuh <hmh@debian.org>]

On Mon, Oct 5, 2015, at 22:13, Marvin Renich wrote:
> The discussion started on d-devel; should it be moved back there?  The
> overwhelming majority of opinion seems to be in favor of the change.

We have supported per-package behavior on this for a very long time,
maybe since forever (this is no joke).  We have had packages that
restart after the upgrade instead of stopping before, or that ignore
service start failures during upgrades for *years*.

All it takes is that the package maintainer actually stop to think about
it, consider which behavior is more appropriate to that specific
package, and adjust things appropriately.  There is a damn good reason
why policy does not use "must" to mandate service start/stop/restart
behavior across package updates.

The reason for this thread, an "undesired" behavior of stopping a
package upgrade if the service fails to start, which is the current
default, is both employed by the (likely few) packages that absolutely
depend on it to avoid worse damage down the service/package dependency
chain, as well as by packages that the maintainer did not even think
about the issue (and therefore might or might not need this behavior).

IMO, we should not just "change this default" in the *implementation*
(debhelper, etc), at least not without actually acessing the real risk
of the change.  It does not look like this kind of risk accessment was
done by anyone yet in the d-devel thread.  Just because we expect it to
be low, doesn't mean it doesn't exist or that it won't have a high
impact on the user if it happens.

If the need for this kind of provision in a possible policy text update
(possibly as a foot-note) is contentious, IMHO the matter needs to go
back to d-devel for further discussion.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique de Moraes Holschuh <hmh@debian.org>