[Bug 1798951] Re: Unattended Upgrades failing with variable reference error

[Balint Reczey]

*** This bug is a duplicate of bug 1795696 ***
    https://bugs.launchpad.net/bugs/1795696

** This bug has been marked a duplicate of bug 1795696
   /usr/bin/unattended-upgrade:UnboundLocalError:/usr/bin/unattended-upgrade at 1991:main:do_auto_remove

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to unattended-upgrades in Ubuntu.
https://bugs.launchpad.net/bugs/1798951

Title:
  Unattended Upgrades failing with variable reference error

Status in unattended-upgrades package in Ubuntu:
  New

Bug description:
  When running unattended-upgrades with auto-remove enabled the script
  complains about a variable being referenced before assignment:

  ```
  # unattended-upgrade -d
  [...]
  Removing unused kernel packages: linux-image-4.15.0-32-generic linux-modules-4.15.0-32-generic
  Keeping 2 auto-removable package(s) because it would also remove the following packages which should be kept in this step: [...]
  Traceback (most recent call last):
    File "/usr/bin/unattended-upgrade", line 1991, in <module>
      sys.exit(main(options))
    File "/usr/bin/unattended-upgrade", line 1791, in main
      options.verbose or options.debug, options.dry_run)
    File "/usr/bin/unattended-upgrade", line 1480, in do_auto_remove
      if res:
  UnboundLocalError: local variable 'res' referenced before assignment
  ```

  This causes the apt-daily-upgrade.service to "fail" which then again
  causes no updates to be installed, which means the package does not
  fulfil its purpose:

  ```
  # systemctl status apt-daily-upgrade.service
  ● apt-daily-upgrade.service - Daily apt upgrade and clean activities
     Loaded: loaded (/lib/systemd/system/apt-daily-upgrade.service; static; vendor preset: enabled)
     Active: inactive (dead) since Sat 2018-10-20 06:17:09 CEST; 6h ago
       Docs: man:apt(8)
   Main PID: 32708 (code=exited, status=0/SUCCESS)

  Oct 20 06:16:00 myhost systemd[1]: Starting Daily apt upgrade and clean activities...
  Oct 20 06:17:09 myhost apt.systemd.daily[32708]: Traceback (most recent call last):
  Oct 20 06:17:09 myhost apt.systemd.daily[32708]:   File "/usr/bin/unattended-upgrade", line 1991, in <module>
  Oct 20 06:17:09 myhost apt.systemd.daily[32708]:     sys.exit(main(options))
  Oct 20 06:17:09 myhost apt.systemd.daily[32708]:   File "/usr/bin/unattended-upgrade", line 1791, in main
  Oct 20 06:17:09 myhost apt.systemd.daily[32708]:     options.verbose or options.debug, options.dry_run)
  Oct 20 06:17:09 myhost apt.systemd.daily[32708]:   File "/usr/bin/unattended-upgrade", line 1480, in do_auto_remove
  Oct 20 06:17:09 myhost apt.systemd.daily[32708]:     if res:
  Oct 20 06:17:09 myhost apt.systemd.daily[32708]: UnboundLocalError: local variable 'res' referenced before assignment
  Oct 20 06:17:09 myhost systemd[1]: Started Daily apt upgrade and clean activities.

  # apt-get --just-print upgrade | grep ^Inst | wc -l
  99
  ```

  Mapped to the current source code of the script within the bionic
  branch the error occurs in this line:

  https://git.launchpad.net/ubuntu/+source/unattended-upgrades/tree
  /unattended-
  upgrade?h=ubuntu/bionic&id=165a91cd44a77a03a83c64cd3812831ba26e3a80#n1418

  Used version of the package:

  ```
  # apt-cache policy unattended-upgrades
  unattended-upgrades:
    Installed: 1.1ubuntu1.18.04.5
    Candidate: 1.1ubuntu1.18.04.5
    Version table:
   *** 1.1ubuntu1.18.04.5 500
          500 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
          500 http://archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages
          500 http://mirror.hetzner.de/ubuntu/packages bionic-updates/main amd64 Packages
          500 http://mirror.hetzner.de/ubuntu/packages bionic-updates/main i386 Packages
          100 /var/lib/dpkg/status
       1.1ubuntu1 500
          500 http://archive.ubuntu.com/ubuntu bionic/main amd64 Packages
          500 http://archive.ubuntu.com/ubuntu bionic/main i386 Packages
          500 http://mirror.hetzner.de/ubuntu/packages bionic/main amd64 Packages
          500 http://mirror.hetzner.de/ubuntu/packages bionic/main i386 Packages
  ```

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/unattended-upgrades/+bug/1798951/+subscriptions