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

[Marvin Renich <mrvn@renich.org>]

* Russ Allbery <rra@debian.org> [151005 18:24]:
> I'm also in favor.  However, this is a very substantial change to Debian
> practice, and I'm not sure what process should be used for making this
> kind of decision.  This wasn't a gap in our specification; rather, the
> previous standard was explicitly chosen (by at least some folks).  Failure
> to install was intentional and believed better since it didn't hide
> service failures.

I understand that this was intentional, but it is not the only way to
make sure the user (admin) is informed of the failure.

It was suggested in the discussion on d-devel that some other
notification mechanism could be implemented instead of installation
failure.

I was thinking about a special dpkg trigger that would be handled
internally by dpkg.  Packages would, in their postinst, place a file
containing non-fatal but important failure information in a directory
owned by dpkg.  This info would be printed out by dpkg at the end of the
run, and would also be passed to front ends that asked.

Front ends such as aptitude could ask dpkg for these notifications.  If
a large installation needed to be split into multiple calls to dpkg, the
front end can aggregate the notifications and present them all at the
very end, in whatever way is native to the front end.

One of the other notifications that I, personally, would like to see
this used for is when a configuration file has changes that cannot be
handled automatically.  Currently you are asked in the middle of the
installation; this would not change at all.  But it would be nice to
have a summary at the end of all the config files that had incompatible
changes, regardless of how I answered the dpkg or ucf prompt.

> I feel like this would benefit from a broader discussion than just the
> Policy list, but I'm not sure how to go about that, or what teams in
> particular should weigh in.

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.

...Marvin