AssertionError: Should pass previous_version as str not <type 'NoneType'>

[David D Lowe]

Binary package hint: bzr-builddeb

Here are the steps to reproduce this bug:

~/Programming/openteacher$ bzr branch lp:openteacher trunk
~/Programming/openteacher$ cd trunk
~/Programming/openteacher/trunk$ bzr revert -r 96
~/Programming/openteacher/trunk$ ./setup.py sdist
# output deleted for brevity
~/Programming/openteacher/trunk$ mv dist/openteacher-1.0.tar.gz ../
~/Programming/openteacher/trunk$ cd ..
~/Programming/openteacher$ bzr init debian
Created a repository tree (format: 2a)
Using shared repository: /home/david/Programming/openteacher/
~/Programming/openteacher$ cd debian
~/Programming/openteacher/debian$ bzr merge-upstream ../openteacher-1.0.tar.gz --version 1.0 --package openteacher --distribution debian
bzr: ERROR: exceptions.AssertionError: Should pass previous_version as str not <type 'NoneType'>
# The rest of the output has been deleted for brevity, see the attachments.

ProblemType: Crash
DistroRelease: Ubuntu 10.10
Package: bzr 2.2.0-1
ProcVersionSignature: Ubuntu 2.6.35-22.33-generic-pae 2.6.35.4
Uname: Linux 2.6.35-22-generic-pae i686
Architecture: i386
BzrDebugFlags: set()
BzrVersion: 2.2.0
CrashDb: bzr
Date: Wed Oct 13 00:35:01 2010
ExecutablePath: /usr/bin/bzr
FileSystemEncoding: UTF-8
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release i386 (20091028.5)
InterpreterPath: /usr/bin/python2.6
Locale: en_GB.utf8
Platform: Linux-2.6.35-22-generic-pae-i686-with-Ubuntu-10.10-maverick
ProcCmdline: /usr/bin/python /usr/bin/bzr merge-upstream ../openteacher-1.0.tar.gz --version 1.0 --package openteacher --distribution debian
ProcEnviron:
 SHELL=/bin/bash
 PATH=(custom, user)
 LANG=en_GB.utf8
PythonVersion: 2.6.6
SourcePackage: bzr
Title: bzr crashed with AssertionError in merge_upstream()
UserEncoding: UTF-8
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare