apt-get dist-upgrade shouldn't run when asked to upgrade between two releases

[James Troup]

Binary package hint: apt

apt-get dist-upgrade is not a supported upgrade path for upgrading
from one release to another (e.g. hardy to intrepid). However, I see
a lot of people who a) don't realise it's not a supported upgrade path
(for various reasons) and b) don't even realise do-release-upgrade
exists.

I think it'd be really useful to alter apt to check to see whether the
dist-upgrade it's being asked to do is across releases and refuse to
run if it is (or at least require confirmation like removing essential
packages does) and suggest the user use do-release-upgrade instead.

[Torsten Spindler (tspindler)]

How would the upgrade from one release to the next be best checked? Probably by checking the lsb release codename versus the distribution field in sources.list. This might conflict with users of mirrors that might have renamed that field. So the check needs to be configurable.

[Julian Andres Klode (juliank)]

apt-get is a low-level tool. The people who use it should know what they do. Normal Ubuntu users do not even reach the point where they'd do an apt-get dist-upgrade, so I don't see a problem here.

[Jean-Baptiste Lallement (jibel)]

I'd like to reopen this issue. 16 years later, there are still plenty of *informed* users who change their sources.list, run a dist-upgrade to upgrade the release, and break their system. They then come to the desktop team asking for help to rescue their broken system.

Even if we don't block them completely, apt should display a bit fat warning informing the users that what they are going to do is definitely not recommended, are they sure they want to proceed with the dist-upgrade.

[Julian Andres Klode (juliank)]

Acknowledge. We need to identify a key package and see whether it changes suites compared to the os-release. Usually that's base-files on Debian.

I'll add this to my apt 3.0 UX improvements list.