KeyError in weak ref package cache

[Dmitry-Kogura]

On start update software sometimes update-manager crashes with message:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/aptdaemon/worker.py", line 1041, in _simulate
    trans.unauthenticated = self.__simulate(trans)
  File "/usr/lib/python2.7/dist-packages/aptdaemon/worker.py", line 1156, in __simulate
    unauthenticated = self._get_unauthenticated()
  File "/usr/lib/python2.7/dist-packages/aptdaemon/worker.py", line 347, in _get_unauthenticated
    for pkg in self._iterate_packages():
  File "/usr/lib/python2.7/dist-packages/aptdaemon/worker.py", line 1352, in _iterate_packages
    for enum, pkg in enumerate(self._cache):
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 197, in __iter__
    yield self[pkgname]
  File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 182, in __getitem__
    pkg = self._weakref[key] = Package(self, self._cache[key])
KeyError: '9693634216138521010ce3ac1d73'

Ubuntu 12.04 (behind proxy). Apt 0.8.16~exp12ubuntu10.3

[Launchpad Janitor (janitor)]

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

[Julian Andres Klode (juliank)]

That key does not make sense. The key should be a package name. I don't know what's happening here, but will try to take a closer look.