Unresolvable problem message does not help users and results in less useful bug reports

[Brian Murray]

In UpdateManager/UpdateManager.py the following code exists:

    except SystemError, e:
        msg = ("<big><b>%s</b></big>\n\n%s\n'%s'" %
               (_("Could not calculate the upgrade"),
                _("An unresolvable problem occurred while "
                  "calculating the upgrade.\n\n"
                  "Please report this bug against the 'update-manager' "
                  "package and include the following error message:"),
                e)
               )

The upgrade may not be calculated for a couple of reasons. As an example we have:

E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

 This can be caused by:
 * Upgrading to a pre-release version of Ubuntu
 * Running the current pre-release version of Ubuntu
 * Unofficial software packages not provided by Ubuntu

update-manager knows, or should know, if you are upgrading to a pre-release or running one and should notify the user to try again as this may be due to archive inconsistencies rather than having them file a bug right away.

[Paolo Rotolo (paolorotolo)]

Thanks for reporting this bug and any supporting documentation. Since this bug has enough information provided for a developer to begin work, I'm going to mark it as confirmed and let them handle it from here. Thanks for taking the time to make Ubuntu better!

[RedSingularity (redsingularity)]

Hey Brian, are you going to take care of this one or should I assign it to Michael?
---
Ubuntu Bug Squad volunteer triager
http://wiki.ubuntu.com/BugSquad

[Brian Murray (brian-murray)]

I plan on working on this real soon now.

[Robert Roth (evfool)]

@Brian Murray: what's the status? DId you manage to find out anything on this?

[Brian Murray (brian-murray)]

The same message is produced by ubuntu-release-upgrader's DistUpgrade/DistUpgradeCache.py. These issues should be resolved in tandem.

[Brian Murray (brian-murray)]

Users who have a package in the removal blacklist:

LP: #1245037/VarLogDistupgradeMainlog.txt:2013-10-26 13:40:53,234 ERROR Dist-upgrade failed: 'The package 'postgresql-8.4' is marked for removal buLP: #1245037/VarLogDistupgradeMainlog.txt:2013-10-26 13:40:53,234 ERROR Dist-upgrade failed: 'The package 'postgresql-8.4' is marked for removal but it is in the removal blacklist.'

Will also see this same error message which actually doesn't fall into any of the conditions listed.

[Cylgalad (cylgalad)]

I can't upgrade to saucy (from raring) because of this "bug", which looks very much Microsoftian to me btw.
Is there anything to do to know what's offending the upgrader so I can upgrade to saucy before the next upgrade?

[Brian Murray (brian-murray)]

Log files for the distribution upgrade are kept in /var/log/dist-upgrade. You'll want to start by looking at main.log.

[Cylgalad (cylgalad)]

Thanks but main.log is not very informative.
At first I thought it was lack of lubuntu-desktop (and the crap it installs like OBSOLETE xscreensaver) that was the problem, but I did apt-get install lubuntu-desktop and after that the upgrade still failed.

I must say that ubuntu's upgrade process is a real PIA, but generally the problems happen *after* the upgrade not *before* !
I may want to go back to a distro that is always up-to-date.

[Cris Dywan (kalikiana)]

> grep ERROR /var/log/dist-upgrade/main.log
2014-11-21 13:32:56,186 ERROR Dist-upgrade failed: 'Das Paket »ubuntu-desktop-next« ist zum Löschen vorgesehen, wurde aber durch das System gesperrt.'

For me the log did contain the offending failure. Question is, why doesn't the UI handle this. Showing the very same error message, which is even localized, would help a lot, even if it means manually taking care of it.

[DLMiller (dlm-miller)]

So what is the resolution to problem seems it was reported in 2012. All I want to do is upgrade to Ubuntu 15.04

[Brian Murray (brian-murray)]

The problem messages are now more informative:

            # the most likely problem is the 3rd party pkgs so don't address
            # foreignPkgs and devRelease being True
            details = _("An unresolvable problem occurred while "
                         "calculating the upgrade.\n\n ")
            if self.config.get("Options", "foreignPkgs") == "True":
                details += _("This was likely caused by:\n"
                             " * Unofficial software packages not provided by Ubuntu\n"
                             "Please use the tool 'ppa-purge' from the ppa-purge \n"
                             "package to remove software from a Launchpad PPA and \n"
                             "try the upgrade again.\n"
                             "\n")
            elif self.config.get("Options", "foreignPkgs") == "False" and \
                self.config.get("Options", "devRelease") == "True":
                details += _("This was caused by:\n"
                              " * Upgrading to a pre-release version of Ubuntu\n"
                              "This is most likely a transient problem, \n"
                              "please try again later.\n")
            # we never have partialUpgrades (including removes) on a stable system
            # with only ubuntu sources so we do not recommend reporting a bug
            if partialUpgrade:
                details += _("This is most likely a transient problem, "
                             "please try again later.")
            else:
                details += _("If none of this applies, then please report this bug using "
                             "the command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. ")
                details += _("If you want to investigate this yourself the log files in "
                             "'/var/log/dist-upgrade' will contain details about the upgrade. "
                             "Specifically, look at 'main.log' and 'apt.log'.")
            # make the error text available again on stdout for the
            # text frontend
            self._stopAptResolverLog()
            view.error(_("Could not calculate the upgrade"), details)

[Muhammad Adnan Ahmed (madnanahmedss)]

An unresolvable problem occurred while calculating the upgrade.

 This was likely caused by:
 * Unofficial software packages not provided by Ubuntu
Please use the tool 'ppa-purge' from the ppa-purge
package to remove software from a Launchpad PPA and
try the upgrade again.

If none of this applies, then please report this bug using the command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. If you want to investigate this yourself the log files in '/var/log/dist-upgrade' will contain details about the upgrade. Specifically, look at 'main.log' and 'apt.log'.

[Moshe Caspi (mcaspi12)]

Muhammad, see this:
Please use the tool 'ppa-purge' from the ppa-purge
package to remove software from a Launchpad PPA and
try the upgrade again.

[Moshe Caspi (mcaspi12)]

"Please use the tool 'ppa-purge' from the ppa-purge
package to remove software from a Launchpad PPA".

Brian, this kind of message won't help my mom or someone like her solve the problem. If you want people like them to use Ubuntu, I think that all these messages should look like this:
1. Open Terminal.
2. Type: sudo apt install ppa-purge and click Enter.
...

I think that this bug needs to be "In progress" until resolved.