do-release-upgrade should provide a way to upgrade to $distro-proposed

[Simon Déziel]

It seems there is no way to do a release upgrade to $distro-proposed. do-release-upgrade has the --proposed flag but that only tells it to use the upgrader from $distro-proposed.

When validating bug fixes for distro upgrade problem (like LP: #1865218), it would be handy to have do-release-upgrade enable $distro-proposed in the sources.list.

Maybe 'do-release-upgrade --to-proposed' could be used for this?

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.37
ProcVersionSignature: Ubuntu 5.3.0-53.47~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-53-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.14
Architecture: amd64
CrashDB: ubuntu
Date: Tue May 26 21:07:14 2020
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 LANG=C.UTF-8
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2020-05-26 (0 days ago)

[Bryce Harrington (bryce)]

We ended up not requiring this, as the SRU found another way to get uploaded. :-)

However, I did look into how we might go about implementing this. In case it might help someone else needing similar some day, here's what I was thinking:

* In do-release-upgrade, add a new command line option such as '--allow-proposed'. Like for options.allow_third_party, this option would set an environment variable "RELEASE_UPGRADER_ALLOW_PROPOSED" to "True"

* In data/DistUpgrade.cfg, at the end of the [Sources] section add a ";AllowProposed=False".

* In DistUpgradeController::rewriteSourcesList(), after the code that uses the config and env var settings to set mirror_check, add a similar section for a new 'allow_proposed=False' variable.

* Also in DistUpgradeController::rewriteSourcesList(), update the clause that does the actual proposed disablement should be modified to look like this:

            # Disable proposed on upgrade to a development release.
            if (not entry.disabled
                and not allow_proposed
                and self.options and self.options.devel_release == True
                and "%s-proposed" % self.fromDist in entry.dist):
                logging.debug("upgrade to development release, disabling proposed")
                entry.dist = "%s-proposed" % self.toDist
                entry.comment += _("Not for humans during development stage of release %s") % self.toDist
                entry.disabled = True
                continue

I *think* that's the correct logic. This should skip the removal of -proposed for any release, so if you enable proposed on your current system, it should leave proposed enabled on the target distro. The routine has a lot of branches so I may have missed some clause; I'd test well.

This wouldn't permit upgrading to a proposed distro from a non-proposed distro. If that functionality is wanted, then support would also need added for that. Probably somewhere around the loop that adds -updates and -security.

[Launchpad Janitor (janitor)]

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