Bug#911771: IPv4: AttributeError: 'module' object has no attribute 'in_' = Missing version constraint on python-attr dependencies

[Ulrike Uhlig]

After some research, this is actually not due to python-twisted but to a
change in the API of python-attrs in 17.1.0
(http://www.attrs.org/en/stable/changelog.html).

But python-twisted from stretch-backports has no versioned dependency on
python-attrs > 17.1.0. Installing python-attrs from stretch-backports
fixes the issue.

#910056 seems to concern the same problem and possibly #911771 should be
merged with it.

Ulrike

Bug#911771: IPv4: AttributeError: 'module' object has no attribute 'in_'

[Ulrike Uhlig]

package: python-twisted
severity:  normal

Dear Maintainer,

when launching torbrowser-launcher, that relies on python-twisted, I get
the following error:

  File "/usr/bin/torbrowser-launcher", line 29, in 
import torbrowser_launcher
  File
"/usr/lib/python2.7/dist-packages/torbrowser_launcher/__init__.py", line
33, in 
from .common import Common, SHARE
  File "/usr/lib/python2.7/dist-packages/torbrowser_launcher/common.py",
line 55, in 
from twisted.internet import gtk2reactor
  File
"/usr/lib/python2.7/dist-packages/twisted/internet/gtk2reactor.py", line
23, in 
from twisted.internet import _glibbase
  File "/usr/lib/python2.7/dist-packages/twisted/internet/_glibbase.py",
line 20, in 
from twisted.internet import base, posixbase, selectreactor
  File "/usr/lib/python2.7/dist-packages/twisted/internet/base.py", line
27, in 
from twisted.internet._resolver import (
  File "/usr/lib/python2.7/dist-packages/twisted/internet/_resolver.py",
line 25, in 
from twisted.internet.address import IPv4Address, IPv6Address
  File "/usr/lib/python2.7/dist-packages/twisted/internet/address.py",
line 23, in 
class IPv4Address(object):
  File "/usr/lib/python2.7/dist-packages/twisted/internet/address.py",
line 37, in IPv4Address
type = attr.ib(validator=attr.validators.in_(["TCP", "UDP"]))

I'm using 18.7.0-2~bpo9+1 and
python 2.7.13-2 (as the default on Stretch).

Cheers,
u.