do-release-upgrade incorrectly reports no upgrade available

[rew]

I just created a "chroot" oneiric. I then ran do-release-upgrade to go to precise. Next I changed "Prompt=ltr" back to "Prompt=normal" (in update-manager/release-upgrades).

Then when I ran do-release-upgrade again, to try to upgrade to quantal I got "no upgrade available", while we're up to rascal already.

It turns out that my resolv.conf had become invalid during the upgrade to precise. That's not the problem. The problem is that do-release-upgrade apparently encounters an error (host cannot be resolved), and instead of reporting on the error reports a "valid output" for the program.

I recognize that people might be offline and therefore get resolver errors. But the good thing about Linux is that you get error messages that help you solve the problem. So in this case a:

no upgrade available because: can't resolve hostname upgrade.ubuntu.com

- maintains the "business part" that no upgrade is currently possible,
- but in case that is an error that can/needs to be solved, provides a hint as to what is wrong.

This was when upgrading from Precise to Quantal. It's a bug that needs "fixing" in an older release first, because for the current release the message "no release available" is the proper one. (hmmm. well if you just change the error message that should be testable).....

[Tv (tv42)]

This just bit me upgrading 13.10 -> 14.04.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.