[Python-modules-team] Bug#796889: python-xlib: UnicodeDecodeError on instantiating Xlib.xauth.Xauthority

[Mel Collins]

Package: python-xlib
Version: 0.14+20091101-4
Severity: grave
Justification: renders package unusable

Dear Maintainer,

After upgrading python-xlib (or python3-xlib) to 0.14+20091101-3 (or -4),
attempting to instantiate an Xauthority instance (eg. via attempting to get a
Display()) fails with a UnicodeDecodeError:

$ python
Python 2.7.10 (default, Jul  1 2015, 10:54:53)
[GCC 4.9.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from Xlib import xauth
>>> xauth.Xauthority()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/dist-packages/Xlib/xauth.py", line 84, in __init__
    self.entries.append((family, addr.decode('UTF-8'),
  File "/usr/lib/python2.7/encodings/utf_8.py", line 16, in decode
    return codecs.utf_8_decode(input, errors, True)
UnicodeDecodeError: 'utf8' codec can't decode byte 0xac in position 0: invalid
start byte

Following the logic of Xauthority.__init__ indicates my ~/.Xauthority file has:

>>> raw[4:8] # first addr
'\xac\x11\x11\x89'


Downgrading to 0.14+20091101-1 from Jessie fixes the issue:

$ python
Python 2.7.10 (default, Jul  1 2015, 10:54:53)
[GCC 4.9.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from Xlib import xauth
>>> xauth.Xauthority()
<Xlib.xauth.Xauthority instance at 0x7fd2656ec8c0>



-- System Information:
Debian Release: stretch/sid
  APT prefers testing
  APT policy: (900, 'testing'), (500, 'testing-updates'), (500, 'unstable'), 
(1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.1.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages python-xlib depends on:
pn  python:any  <none>

python-xlib recommends no packages.

python-xlib suggests no packages.

-- no debconf information