Here's the hpss trace in case that helps. It's reproducible, at least on this branch. Fri 2009-06-19 19:51:01 +1000 0.026 bzr arguments: [u'-Dhpss', u'diff', u'-c', u'4148', u'lp:~mbp/bzr/progress'] 0.043 looking for plugins in /home/mbp/.bazaar/plugins [16744] 2009-06-19 19:51:02.001 WARNING: Unable to load plugin 'gtk'. It requested API version (1, 15, 0) of module but the minimum exported version is (1, 17, 0), and the maximum is (1, 17, 0) 0.121 looking for plugins in /home/mbp/bzr/progress/bzrlib/plugins 0.142 looking for plugins in /usr/lib/python2.6/dist-packages/bzrlib/plugins 0.143 Plugin name netrc_credential_store already loaded 0.143 Plugin name launchpad already loaded 0.148 Returning RevisionSpec RevisionSpec_before for before:4148 2.402 hpss: Built a new medium: SmartSSHClientMedium 2.427 hpss call: 'BzrDir.open', '~mbp/bzr/progress/' 2.427 (to bzr+ssh://bazaar.launchpad.net/%7Embp/bzr/progress/) 2.474 ssh implementation is OpenSSH 10.193 result: ('yes',) 10.194 hpss call: 'BzrDir.open_branchV2', '~mbp/bzr/progress/' 10.194 (to bzr+ssh://bazaar.launchpad.net/%7Embp/bzr/progress/) 10.564 result: ('branch', 'Bazaar Branch Format 7 (needs bzr 1.6)\n') 10.564 hpss call: 'BzrDir.find_repositoryV3', '~mbp/bzr/progress/' 10.564 (to bzr+ssh://bazaar.launchpad.net/%7Embp/bzr/progress/) 10.931 result: ('ok', '', 'no', 'no', 'yes', 'Bazaar RepositoryFormatKnitPack6 (bzr 1.9)\n') 10.954 hpss call: 'Branch.get_stacked_on_url', '~mbp/bzr/progress/' 10.955 (to bzr+ssh://bazaar.launchpad.net/%7Embp/bzr/progress/) 11.339 result: ('ok', '/~bzr/bzr/trunk') 11.340 hpss call: 'BzrDir.open', '~bzr/bzr/trunk/' 11.340 (to bzr+ssh://bazaar.launchpad.net/%7Embp/bzr/progress/) 11.799 result: ('yes',) 11.799 hpss call: 'BzrDir.open_branchV2', '~bzr/bzr/trunk/' 11.799 (to bzr+ssh://bazaar.launchpad.net/%7Embp/bzr/progress/) 12.168 result: ('branch', 'Bazaar Branch Format 7 (needs bzr 1.6)\n') 12.168 hpss call: 'BzrDir.find_repositoryV3', '~bzr/bzr/trunk/' 12.168 (to bzr+ssh://bazaar.launchpad.net/%7Embp/bzr/progress/) 12.534 result: ('ok', '', 'no', 'no', 'yes', 'Bazaar RepositoryFormatKnitPack6 (bzr 1.9)\n') 12.535 hpss call: 'Branch.get_stacked_on_url', '~bzr/bzr/trunk/' 12.535 (to bzr+ssh://bazaar.launchpad.net/%7Embp/bzr/progress/) 12.906 result: ('NotStacked',) 12.907 hpss call: 'Branch.last_revision_info', '~mbp/bzr/progress/' 12.907 (to bzr+ssh://bazaar.launchpad.net/%7Embp/bzr/progress/) 13.281 result: ('ok', '4148', '