python3-twisted seems to be broken for txfixture package

[Rafael David Tinoco]

When trying to package txfixture using regular python3-twisted package I get this:

$ ps auxwww | grep cannotlis
ubuntu 46610 0.5 0.8 34884 29268 pts/1 S+ 19:33 0:00 /usr/bin/python3.5 -Wignore::DeprecationWarning /usr/bin/twistd -o -y /home/ubuntu/source/packages/txfixture/recipe/.pybuild/pythonX.Y_3.5/build/tests/cannotlisten.tac --pidfile /tmp/tmpiae4_7c4/cannotlisten.pid --logfile /tmp/tmpiae4_7c4/cannotlisten.log

$ cat /tmp/tmpiae4_7c4/cannotlisten.log
2017-07-21 19:33:54+0000 [-] Log opened.
2017-07-21 19:33:54+0000 [-] twistd 16.0.0 (/usr/bin/python3.5 3.5.2) starting up.
2017-07-21 19:33:54+0000 [-] reactor class: twisted.internet.epollreactor.EPollReactor.
2017-07-21 19:33:54+0000 [-] Traceback (most recent call last):
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/internet/tcp.py", line 982, in startListening
2017-07-21 19:33:54+0000 [-] skt.bind(addr)
2017-07-21 19:33:54+0000 [-] PermissionError: [Errno 13] Permission denied
2017-07-21 19:33:54+0000 [-]
2017-07-21 19:33:54+0000 [-] During handling of the above exception, another exception occurred:
2017-07-21 19:33:54+0000 [-]
2017-07-21 19:33:54+0000 [-] Traceback (most recent call last):
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/scripts/_twistd_unix.py", line 207, in postApplication
2017-07-21 19:33:54+0000 [-] self.startApplication(self.application)
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/scripts/_twistd_unix.py", line 394, in startApplication
2017-07-21 19:33:54+0000 [-] service.IService(application).privilegedStartService()
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/application/service.py", line 278, in privilegedStartService
2017-07-21 19:33:54+0000 [-] service.privilegedStartService()
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/application/internet.py", line 106, in privilegedStartService
2017-07-21 19:33:54+0000 [-] self._port = self._getPort()
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/application/internet.py", line 134, in _getPort
2017-07-21 19:33:54+0000 [-] 'listen%s' % (self.method,))(*self.args, **self.kwargs)
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/internet/posixbase.py", line 478, in listenTCP
2017-07-21 19:33:54+0000 [-] p.startListening()
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/internet/tcp.py", line 984, in startListening
2017-07-21 19:33:54+0000 [-] raise CannotListenError(self.interface, self.port, le)
2017-07-21 19:33:54+0000 [-] twisted.internet.error.CannotListenError: Couldn't listen on any:1: [Errno 13] Permission denied.
2017-07-21 19:33:54+0000 [-]
2017-07-21 19:33:54+0000 [-] During handling of the above exception, another exception occurred:
2017-07-21 19:33:54+0000 [-]
2017-07-21 19:33:54+0000 [-] Traceback (most recent call last):
2017-07-21 19:33:54+0000 [-] File "/usr/bin/twistd", line 18, in <module>
2017-07-21 19:33:54+0000 [-] run()
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/scripts/twistd.py", line 29, in run
2017-07-21 19:33:54+0000 [-] app.run(runApp, ServerOptions)
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/application/app.py", line 617, in run
2017-07-21 19:33:54+0000 [-] runApp(config)
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/scripts/twistd.py", line 25, in runApp
2017-07-21 19:33:54+0000 [-] _SomeApplicationRunner(config).run()
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/application/app.py", line 352, in run
2017-07-21 19:33:54+0000 [-] self.postApplication()
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/scripts/_twistd_unix.py", line 213, in postApplication
2017-07-21 19:33:54+0000 [-] untilConcludes(os.write, statusPipe, "1 %s" % (strippedError,))
2017-07-21 19:33:54+0000 [-] File "/usr/lib/python3/dist-packages/twisted/python/util.py", line 713, in untilConcludes
2017-07-21 19:33:54+0000 [-] return f(*a, **kw)
2017-07-21 19:33:54+0000 [-] TypeError: a bytes-like object is required, not 'str'

And txfixture package hangs in

tests.test_tachandler.TacTestFixtureTestCase.test_couldNotListenTac

Because the exception is not caught by twisted (that had exception itself).

"twisted" package found at:

https://launchpad.net/~ubuntu-debian-backports/+archive/ubuntu/sid

seems to be able to solve this.

I guess changes in between those 2 versions fix this issue.