"AssertionError: paths must be Unicode strings" when starting a node

[daira]

I have tried to install tahoe-lafs on ubuntu 14.04.1 from github source.

All tests are passed, like in travis. But when I try to run the binary: tahoe start

I got the following error:

STARTING '/home/tahoe_user/.tahoe'
starting node in '/home/tahoe_user/.tahoe'
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/allmydata/scripts/runner.py", line 156, in run
    rc = runner(sys.argv[1:], install_node_control=install_node_control)
  File "/usr/local/lib/python2.7/dist-packages/allmydata/scripts/runner.py", line 135, in runner
    rc = startstop_node.dispatch[command](so, stdout, stderr)
  File "/usr/local/lib/python2.7/dist-packages/allmydata/scripts/startstop_node.py", line 159, in start
    twistd.runApp(twistd_config)
  File "/usr/lib/python2.7/dist-packages/twisted/scripts/twistd.py", line 23, in runApp
    _SomeApplicationRunner(config).run()
  File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 376, in run
    self.application = self.createOrGetApplication()
  File "/usr/lib/python2.7/dist-packages/twisted/application/app.py", line 436, in createOrGetApplication
    ser = plg.makeService(self.config.subOptions)
  File "/usr/local/lib/python2.7/dist-packages/allmydata/scripts/startstop_node.py", line 68, in makeService
    return Client(self.basedir)
  File "/usr/local/lib/python2.7/dist-packages/allmydata/client.py", line 151, in __init__
    self.init_sftp_server()
  File "/usr/local/lib/python2.7/dist-packages/allmydata/client.py", line 479, in init_sftp_server
    sftp_portstr, pubkey_file, privkey_file)
  File "/usr/local/lib/python2.7/dist-packages/allmydata/frontends/sftpd.py", line 1988, in __init__
    c = AccountFileChecker(self, accountfile)
  File "/usr/local/lib/python2.7/dist-packages/allmydata/frontends/auth.py", line 34, in __init__
    for line in open(abspath_expanduser_unicode(accountfile), "r"):
  File "/usr/local/lib/python2.7/dist-packages/allmydata/util/fileutil.py", line 314, in abspath_expanduser_unicode
    raise AssertionError("paths must be Unicode strings")
AssertionError: paths must be Unicode strings

And here are my version:

/usr/local/bin/tahoe --version-and-path
allmydata-tahoe: 1.10.0.post272 [master: e9e63c5e72619f4e5811cd1eed31e344db6236c8] (/usr/local/lib/python2.7/dist-packages)
foolscap: 0.6.4 (/usr/lib/python2.7/dist-packages)
pycryptopp: 0.6.0.1206569328141510525648634803928199668821045408958 (/usr/lib/python2.7/dist-packages)
zfec: 1.4.5 (/usr/lib/python2.7/dist-packages)
Twisted: 13.2.0 (/usr/lib/python2.7/dist-packages)
Nevow: 0.11.1 (/usr/local/lib/python2.7/dist-packages)
zope.interface: unknown (/usr/lib/python2.7/dist-packages/zope)
python: 2.7.6 (/usr/bin/python)
platform: Linux-Ubuntu_14.04-x86_64-64bit_ELF (None)
pyOpenSSL: 0.13 (/usr/lib/python2.7/dist-packages)
simplejson: 3.3.1 (/usr/lib/python2.7/dist-packages)
pycrypto: 2.6.1 (/usr/lib/python2.7/dist-packages)
pyasn1: 0.1.7 (/usr/lib/python2.7/dist-packages)
mock: 1.0.1 (/usr/lib/python2.7)
setuptools: 3.3 (/usr/lib/python2.7/dist-packages)
service-identity: 14.0.0 (/usr/local/lib/python2.7/dist-packages)
characteristic: 14.3.0 (/usr/local/lib/python2.7)
pyasn1-modules: 0.0.5 (/usr/local/lib/python2.7/dist-packages)