unattended-upgrade crashed with AttributeError in _write(): 'NoneType' object has no attribute 'write'

[Raony Guimarães]

This happened after upgrading it to Artful.

ProblemType: Crash
DistroRelease: Ubuntu 17.10
Package: unattended-upgrades 0.93.1ubuntu3
ProcVersionSignature: Ubuntu 4.10.0-20.22-generic 4.10.8
Uname: Linux 4.10.0-20-generic x86_64
ApportVersion: 2.20.4-0ubuntu6
Architecture: amd64
CrashCounter: 1
Date: Tue May 9 08:20:24 2017
ExecutablePath: /usr/bin/unattended-upgrade
InstallationDate: Installed on 2017-05-05 (3 days ago)
InstallationMedia: Ubuntu-MATE 17.04 "Zesty Zapus" - Release amd64 (20170412)
InterpreterPath: /usr/bin/python3.5
PackageArchitecture: all
ProcCmdline: /usr/bin/python3 /usr/bin/unattended-upgrade -d 3
ProcEnviron:
 LANGUAGE=en_IE:en
 PATH=(custom, no user)
 LANG=en_IE.UTF-8
PythonArgs: ['/usr/bin/unattended-upgrade', '-d', '3']
SourcePackage: unattended-upgrades
Title: unattended-upgrade crashed with AttributeError in _write(): 'NoneType' object has no attribute 'write'
UpgradeStatus: Upgraded to artful on 2017-05-05 (3 days ago)
UserGroups:

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Robie Basak (racb)]

Still affects me on Artful with 0.93.1ubuntu4. uklas, why did you change this to Fix Released with no explanation?

[Brian Murray (brian-murray)]

Robie - Do you have any more information about how this crash occurs and its effects?

[Robie Basak (racb)]

The first I knew of it was an apport/whoopsie GUI popup, which then sent me to this bug IIRC. I installed this machine fresh from an Artful daily. The only relevant change I think I made was to add an apt proxy in /etc/apt.conf.d/. I don't have any other information and didn't save my traceback, assuming it was the same as in this report. I haven't seen the issue since, though I don't know if that's due to whoopsie suppression.