TypeError: pull() got an unexpected keyword argument 'show_base'

Imported from Debian bug http://bugs.debian.org/679387:

Package: bzr-svn
Version: 1.2.1-1
Severity: minor

Running "bzr pull <branch>" on a Subversion checkout generated a stack
backtrace and the following error:

bzr: ERROR: exceptions.TypeError: pull() got an unexpected keyword argument 'show_base'

I don't necessarily expect this to work, but a nicer error message would
be good, hence priority "minor".

Full steps to reproduce below:

wraith:/tmp/pull-bug$ bzr init bzr
Created a standalone tree (format: 2a)
wraith:/tmp/pull-bug$ svnadmin create svn-repo
wraith:/tmp/pull-bug$ svn mkdir -m '' file://${PWD}/svn-repo/trunk

Committed revision 1.
wraith:/tmp/pull-bug$ svn checkout file://${PWD}/svn-repo/trunk svn-checkout
Checked out revision 1.
wraith:/tmp/pull-bug$ cd svn-checkout
wraith:/tmp/pull-bug/svn-checkout$ bzr pull ../bzr
Initialising Subversion metadata cache in
/home/bjh21/.bazaar/svn-cache/51b7064b-8ce7-457f-aaa6-716cb730721e.
bzr: ERROR: exceptions.TypeError: pull() got an unexpected keyword argument 'show_base'

Traceback (most recent call last):
   File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 930, in exception_to_return_code
     return the_callable(*args, **kwargs)
   File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 1141, in run_bzr
     ret = run(*run_argv)
   File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 673, in run_argv_aliases
     return self.run(**all_cmd_args)
   File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 697, in run
     return self._operation.run_simple(*args, **kwargs)
   File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 136, in run_simple
     self.cleanups, self.func, *args, **kwargs)
   File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 166, in _do_with_cleanups
     result = func(*args, **kwargs)
   File "/usr/lib/python2.7/dist-packages/bzrlib/builtins.py", line 1244, in run
     local=local, show_base=show_base)
TypeError: pull() got an unexpected keyword argument 'show_base'

bzr 2.6.0dev2 on python 2.7.3rc2 (Linux-3.2.0-2-686-pae-i686-with-debian-
     wheezy-sid)
arguments: ['/usr/bin/bzr', 'pull', '../bzr']
plugins: bash_completion[2.6.0dev2], bzrtools[2.5.0],
     changelog_merge[2.6.0dev2], dbus[0.1.0dev], git[0.6.9],
gtk[0.104.0dev],
     launchpad[2.6.0dev2], netrc_credential_store[2.6.0dev2],
     news_merge[2.6.0dev2], po_merge[2.6.0dev2], search[1.7.0dev],
     svn[1.2.1],
     weave_fmt[2.6.0dev2]
encoding: 'ascii', fsenc: 'utf8', lang: None

*** Bazaar has encountered an internal error. This probably indicates a
     bug in Bazaar. You can help us fix it by filing a bug report at
         https://bugs.launchpad.net/bzr/+filebug
     including this traceback and a description of the problem.

-- System Information:
Debian Release: wheezy/sid
   APT prefers testing
   APT policy: (500, 'testing')
Architecture: i386 (i686)

Kernel: Linux 3.2.0-2-686-pae (SMP w/2 CPU cores)
Locale: LANG=C, LC_CTYPE=C (charmap=ANSI_X3.4-1968)
Shell: /bin/sh linked to /bin/bash

Versions of packages bzr-svn depends on:
ii python 2.7.3~rc2-1
ii python-bzrlib 2.6.0~bzr6522-1
ii python-subvertpy 0.8.10-2
ii python2.6 2.6.7-4
ii python2.7 2.7.3~rc2-2.1

Versions of packages bzr-svn recommends:
ii bzr 2.6.0~bzr6522-1
ii python-tdb 1.2.10-2
ii python-xdg 0.19-4

Versions of packages bzr-svn suggests:
pn bzr-rewrite <none>

-- no debconf information

--
Ben Harris, University of Cambridge Computing Service.