pycentral breaks if /usr/bin/dpkg-querry fails to read trigger enabled status file (was: Feisty to Gutsy Upgrade: Aborts with partial upgrade)

[Stephen Eisenhauer]

Binary package hint: update-manager

The desktop ran Feisty, up-to-date as of 10/12/07, and I used "update-manager -c -d" to upgrade to Gutsy RC1 on that same date. The installed architecture was i386, although the CPU is really an amd64. I have 768MB of RAM.

Come the installation phase of the upgrade, I received a slew of message windows indicating the failure of x package to install. Among these were (and I apologize if I made any mistakes transcribing the names):

baseutils
bash
adduser
passwd
ssl-cert
cupsys
python-apt
dbus
libgnomevfs2-0
libgnome2-0
libbonoboui2-0
libgnomeui2-0

with the given reason being "dependency problems - leaving unconfigured".

After these messages I received the closing remarks:
"Could not install the upgrades

The upgrade aborts now. Your system could be in an unusable state. A recovery will run now (dpkg --configure -a).

Please report this bug against the 'update-manager' package and include the files in /var/log/dist-upgrade/ in the bugreport.
installArchives() failed"

It proceeded with the dpkg --configure business, and the installer closed without notice. I have yet to reboot and see if the resultant installation works. Attachments to follow. Thanks!

[Stephen Eisenhauer (bhspitmonkey)]

Requested attachments.

[Michael Vogt (mvo)]

The problem is that pycentral uses /usr/bin/dpkg-querry (with explicit path) to ask for a filelist in the postinst of all appylications that use python-central. This breaks when python-apt is configured before the new dpkg is available in /usr/bin/dpkg{-querry} (the upgrader uses its own private version build against the old libraries of feisty).

[Michael Vogt (mvo)]

I can reproduce the failure on a server install with:
$ sudo apt-get install python-all-dev python-vte dpkg-dev python-all

installed.

[Martin Pitt (pitti)]

 python-apt (0.7.3.1ubuntu4) gutsy; urgency=low
 .
   * pre-depend on gutsy version pycentral, this ensures that we get a
     updated dpkg with triggers support before pycentral uses
     /usr/bin/dpkg-querry (LP: #152827)