Comment 4 for bug 396261

A bare 'bzr help' gives:

bzr help
bzr: ERROR: exceptions.SystemError: NULL result without error in PyObject_Call

Traceback (most recent call last):
  File "/home/vila/src/bzr/trunk/bzrlib/commands.py", line 843, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/home/vila/src/bzr/trunk/bzrlib/commands.py", line 1044, in run_bzr
    ret = run(*run_argv)
  File "/home/vila/src/bzr/trunk/bzrlib/commands.py", line 655, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/home/vila/src/bzr/trunk/bzrlib/commands.py", line 1059, in ignore_pipe
    result = func(*args, **kwargs)
  File "/home/vila/src/bzr/trunk/bzrlib/builtins.py", line 4158, in run
    bzrlib.help.help(topic)
  File "/home/vila/src/bzr/trunk/bzrlib/help.py", line 46, in help
    topics = indices.search(topic)
  File "/home/vila/src/bzr/trunk/bzrlib/help.py", line 156, in search
    result.extend([(index, _topic) for _topic in index.get_topics(topic)])
  File "/home/vila/src/bzr/trunk/bzrlib/commands.py", line 1172, in get_topics
    cmd = _get_cmd_object(topic)
  File "/home/vila/src/bzr/trunk/bzrlib/commands.py", line 238, in _get_cmd_object
    cmd = hook(cmd_name)
  File "/home/vila/.bazaar/plugins/guess/__init__.py", line 38, in guess_command
    matcher = patiencediff.PatienceSequenceMatcher(None, cmd_name, name)
SystemError: NULL result without error in PyObject_Call

bzr 2.1.0dev4 on python 2.6.4 (Linux-2.6.31-15-generic-x86_64-with-Ubuntu-9.10-karmic)
arguments: ['/home/vila/bin/bzr', 'help']
encoding: 'UTF-8', fsenc: 'UTF-8', lang: 'en_US.UTF-8'
plugins:
  bookmarks /home/vila/.bazaar/plugins/bookmarks [unknown]
  builddeb /home/vila/.bazaar/plugins/builddeb [2.1.1dev]
  builder /home/vila/.bazaar/plugins/builder [unknown]
  bzrtools /home/vila/.bazaar/plugins/bzrtools [2.1.0b1]
  diffstat /home/vila/.bazaar/plugins/diffstat [0.2.0]
  email /home/vila/.bazaar/plugins/email [unknown]
  explorer /home/vila/.bazaar/plugins/explorer [0.10.0dev]
  fix277537 /home/vila/.bazaar/plugins/fix277537 [unknown]
  gtk /home/vila/.bazaar/plugins/gtk [0.98.0dev1]
  guess /home/vila/.bazaar/plugins/guess [unknown]
  launchpad /home/vila/src/bzr/trunk/bzrlib/plugins/launchpad [2.1.0dev4]
  local_test_server /home/vila/.bazaar/plugins/local_test_server [unknown]
  loom /home/vila/.bazaar/plugins/loom [1.4.0dev]
  netrc_credential_store /home/vila/src/bzr/trunk/bzrlib/plugins/netrc_credential_store [2.1.0dev4]
  qbzr /home/vila/.bazaar/plugins/qbzr [0.17.0dev]
  stats /home/vila/.bazaar/plugins/stats [unknown]
  upload /home/vila/.bazaar/plugins/upload [1.0.0dev]

*** 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.

I fixed it, went to report the bug, saw he fixed it in the same way.