/usr/bin/update-manager:ValueError:restart_icon_renderer_data_func:pkg_requires_restart:__get_candidate

[errors.ubuntu.com bug bridge]

The Ubuntu Error Tracker has been receiving reports about a problem regarding update-manager. This problem was most recently seen with package version 1:18.04.11, the problem page at https://errors.ubuntu.com/problem/a2ba8d3ab5e432b3c15f172ded6d473f4c00720a contains more details, including versions of packages affected, stacktrace or traceback, and individual crash reports.
If you do not have access to the Ubuntu Error Tracker and are a software developer, you can request it at http://forms.canonical.com/reports/.

[Brian Murray (brian-murray)]

The Traceback follows:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/UpdateManager/UpdatesAvailable.py", line 417, in restart_icon_renderer_data_func
    group_item.pkg):
  File "/usr/lib/python3/dist-packages/UpdateManager/UpdatesAvailable.py", line 391, in pkg_requires_restart
    if pkg is None or pkg.candidate is None:
  File "/usr/lib/python3/dist-packages/apt/package.py", line 1031, in __get_candidate
    cand = self._pcache._depcache.get_candidate_ver(self._pkg)
ValueError: Object of different cache passed as argument to apt_pkg.DepCache method

[Julian Andres Klode (juliank)]

This is a safety check added in python-apt to prevent old package objects being reused in new (dep)caches. since the cache operates on package ids, and the package ids might change, there are three things that can happen:

(1) If # of packages in new cache < # in old cache: SEGV
(2) If id changed, functions called on the package might operate on a different package
(3) If you are lucky, everything works

[Launchpad Janitor (janitor)]

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