I should mention: I was trying `brz` in a git repository checked out from git.  Fixing the above produces a new bug:

brz info
brz: ERROR: TypeError: a bytes-like object is required, not 'str'

Traceback (most recent call last):
  File "/opt/pkg/lib/python3.7/site-packages/breezy/commands.py", line 1009, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/commands.py", line 1194, in run_bzr
    ret = run(*run_argv)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/commands.py", line 760, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/commands.py", line 784, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/cleanup.py", line 136, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/cleanup.py", line 165, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/commands.py", line 1211, in ignore_pipe
    result = func(*args, **kwargs)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/builtins.py", line 1844, in run
    verbose=noise_level, outfile=self.outf)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/info.py", line 354, in show_bzrdir_info
    recommend_upgrade=False)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/git/dir.py", line 593, in open_workingtree
    return GitWorkingTree(self, repo, branch)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/git/workingtree.py", line 122, in __init__
    self._reset_data()
  File "/opt/pkg/lib/python3.7/site-packages/breezy/git/workingtree.py", line 677, in _reset_data
    self.store.__getitem__, self.store[head].tree)
  File "/opt/pkg/lib/python3.7/site-packages/dulwich/object_store.py", line 119, in __getitem__
    type_num, uncomp = self.get_raw(sha)
  File "/opt/pkg/lib/python3.7/site-packages/dulwich/object_store.py", line 446, in get_raw
    for pack in self.packs:
  File "/opt/pkg/lib/python3.7/site-packages/breezy/git/transportgit.py", line 594, in packs
    self._update_pack_cache()
  File "/opt/pkg/lib/python3.7/site-packages/breezy/git/transportgit.py", line 598, in _update_pack_cache
    for pack in self._load_packs():
  File "/opt/pkg/lib/python3.7/site-packages/breezy/git/transportgit.py", line 627, in _load_packs
    size = self.pack_transport.stat(name).st_size
  File "/opt/pkg/lib/python3.7/site-packages/breezy/transport/local.py", line 484, in stat
    path = self._abspath(relpath)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/transport/local.py", line 99, in _abspath
    return self._local_base + urlutils.unescape(relative_reference)
  File "/opt/pkg/lib/python3.7/site-packages/breezy/urlutils.py", line 684, in unescape
    return urlparse.unquote(url)
  File "/opt/pkg/lib/python3.7/urllib/parse.py", line 609, in unquote
    if '%' not in string:
TypeError: a bytes-like object is required, not 'str'

brz 3.0a1 on python 3.7.0 (Darwin-17.7.0-x86_64-i386-64bit)
arguments: ['/opt/pkg/bin/brz', 'info']
plugins: bash_completion[3.0a1], changelog_merge[3.0a1],
    commitfromnews[unknown], cvs[3.0a1], darcs[unknown], email[unknown],
    fastimport[unknown], grep[3.0a1], launchpad[3.0a1], mtn[3.0a1],
    netrc_credential_store[3.0a1], news_merge[3.0a1], po_merge[3.0a1],
    repodebug[unknown], stats[3.0a1], upload[3.0a1], weave_fmt[3.0a1]
encoding: 'utf-8', fsenc: 'utf-8', lang: 'en_CA.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/brz/+filebug
    including this traceback and a description of the problem.