Update Manager / Broken Packages / X Failsafe

[Matt Zimmerman]

On Wed, Aug 23, 2006 at 02:44:25AM -0700, Adam Weiss wrote:
> The interesting thing that I noticed is that when I started the update
> manager after fixing things, it still had stale information.  Clicking on
> "Check" caused it to see the new fixed package, but had I not done so, it
> would have been perfectly happy to reinstall the busted one.
> 
> I'm wondering if this means that the delay time from busted package fix to
> actual install is not just two hours for the replication, but actually 24
> in cases where the package db is updated by the daily cronjob with a
> bad package and the user doesn't actually click the "Check" button.

No; you only encountered this situation because you rolled back to an old
version of the package rather than forward to the fixed version.  The update
system will never replace a newer package from the official repositories
with an older one.

> Would it make sense to change the update manager to automatically try to
> check for updates/refresh whenever it's started?

This can take a rather long time on a dialup connection in some cases, and
since most users only start Update Manager when they see the notification,
it's often up to date already.

> Also, has anyone given any thought to an emergency brake of sorts to halt
> broken packages as soon as they're known broken?  Something like apt does
> a DNS query that is a combination of the package name and some centrally
> controlled domain that if a result comes back- abort the install?  (I
> don't know, that's kinda janky, but you get the idea: some cheap scalable
> way for the maintainers to immeadiately flag a package as bad.)

Some thought, yes.  Serious infrastructure work, no.

> I haven't really looked under the hood, but I wonder if it might make
> sense to add a roll-back feature to the update manager.  Something along
> the lines of when you install a bundle of updates, not only are the
> updates downloaded, but also debs for the stuff you have installed that is
> going to be replaced.  In the event of something serious (like X failing
> to start) a console app could walk the user through a "roll-back"- in less
> serious situations, add a button to the update manager itself.  Purge old
> packages after the machine has been rebooted one and n days have elapsed.
> Something like that...

Package downgrades are, in general, unsupportable and to be avoided, so this
would not be a good default.  It is better to install a fixed version
wherever possible.

-- 
 - mdz