Handle SystemError in apt.cache.Cache.required_download properly

[Raphaël Facchini]

Binary package hint: aptdaemon

I was trying to update and I got an error. Then I wanted to report the bug, and I got this other error.

Ubuntu 11.04
0.41+bzr646-0ubuntu2

ProblemType: Crash
DistroRelease: Ubuntu 11.04
Package: aptdaemon 0.41+bzr646-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
Annotation: Applying software changes failed
Architecture: i386
Date: Mon May 9 22:08:52 2011
DesktopFile: /usr/share/aptdaemon/aptdaemon.desktop
ExecutablePath: /usr/sbin/aptd
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
PackageArchitecture: all
SourcePackage: aptdaemon
Title: <type 'exceptions.SystemError'>: E:The package index files are corrupted. No Filename: field for package tzdata.
TransactionDepends: [[], [], [], [], [], [], []]
TransactionErrorCode: error-unknown
TransactionKwargs: {}
TransactionLocale: fr_BE.UTF8
TransactionOutput:

TransactionPackages: [[], [], [], [], [dbus.String(u'gwibber-service'), dbus.String(u'gwibber-service-facebook'), dbus.String(u'gwibber-service-identica'), dbus.String(u'gwibber-service-twitter'), dbus.String(u'libsyncdaemon-1.0-1'), dbus.String(u'python-ubuntuone-client'), dbus.String(u'tzdata'), dbus.String(u'ubuntuone-client'), dbus.String(u'ubuntuone-client-gnome')], []]
TransactionRole: role-commit-packages
UpgradeStatus: No upgrade log present (probably fresh install)

[Goyo (goyodiaz)]

This is due to corrupted index files (likely an incomplete download) and can be solved by removing the content of /var/lib/apt/lists

sudo rm -r /var/lib/apt/lists/*

(or just the corrupted file if you can identify it)

Anyway it would be nice if this could be handled in a better way. It is unavoidable that it happens every now and then and most users do not have a clue about what to do.