can't use it with oh-my-zsh

[Raphaël ACISCLO]

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 1121, 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/commands.py", line 1138, in ignore_pipe
    result = func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/builtins.py", line 2893, in run
    Logger(b, rqst).show(lf)
  File "/usr/lib/python2.7/dist-packages/bzrlib/log.py", line 382, in show
    self._show_body(lf)
  File "/usr/lib/python2.7/dist-packages/bzrlib/log.py", line 411, in _show_body
    for lr in generator.iter_log_revisions():
  File "/usr/lib/python2.7/dist-packages/bzrlib/log.py", line 450, in iter_log_revisions
    revision_iterator = self._create_log_revision_iterator()
  File "/usr/lib/python2.7/dist-packages/bzrlib/log.py", line 501, in _create_log_revision_iterator
    self.rqst.get('end_revision'))
  File "/usr/lib/python2.7/dist-packages/bzrlib/log.py", line 1043, in _get_revision_limits
    branch_revno, branch_rev_id = branch.last_revision_info()
  File "/usr/lib/python2.7/dist-packages/bzrlib/decorators.py", line 155, in read_locked
    result = unbound(self, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/branch.py", line 1049, in last_revision_info
    self._last_revision_info_cache = self._read_last_revision_info()
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/git/branch.py", line 566, in _read_last_revision_info
    [(revision.NULL_REVISION, 0)])
  File "/usr/lib/python2.7/dist-packages/bzrlib/graph.py", line 370, in find_distance_to_null
    parent_map = self.get_parent_map(to_search)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/git/repository.py", line 376, in get_parent_map
    parents = self._get_parents(revision_id, no_alternates=no_alternates)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/git/repository.py", line 368, in _get_parents
    for p in commit.parents]
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/git/repository.py", line 430, in lookup_foreign_revision_id
    commit = self._git.object_store.peel_sha(foreign_revid)
  File "/usr/lib/python2.7/dist-packages/dulwich/object_store.py", line 218, in peel_sha
    obj = self[sha]
  File "/usr/lib/python2.7/dist-packages/dulwich/object_store.py", line 118, in __getitem__
    type_num, uncomp = self.get_raw(sha)
  File "/usr/lib/python2.7/dist-packages/dulwich/object_store.py", line 384, in get_raw
    raise KeyError(hexsha)
KeyError: 'b4b55fa502af7b545d04045474d1550d57274c42'

bzr 2.8.0dev1 on python 2.7.14rc1 (Linux-4.12.0-1-amd64-x86_64-with-debian-
    buster-sid)
arguments: ['/usr/bin/bzr', 'log']
plugins: bash_completion[2.8.0dev1], changelog_merge[2.8.0dev1], git[0.6.12],
    grep[2.8.0dev1], launchpad[2.8.0dev1], netrc_credential_store[2.8.0dev1],
    news_merge[2.8.0dev1], po_merge[2.8.0dev1], weave_fmt[2.8.0dev1]
encoding: 'utf-8', fsenc: 'UTF-8', lang: 'fr_FR.UTF-8'

*** 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.

There was an update of python 2.7 for debian unstable: It is broken since then.
It crashes every time I do a command on a git repo (Because oh-my-zsh is using bazaar for agnoster, it seems) which is quite annoying.