[Bug 1624644] Re: By default settings unattended-upgrade is unable to automatically remove packages that become unused in conjunction with updating by other software.

[Balint Reczey]

On Wed, Sep 27, 2017 at 1:49 PM, Brian Murray <brian at ubuntu.com> wrote:
> @Balint re "@Jarno: IMO Unattended-Upgrade::Remove-Unused-Dependencies
> is already a risky option and I don't recommend enabling it because it
> may remove packages which are not used according the to package-
> dependency chain but which users rely on using software that is not
> packaged."
>
> Could you give me an example of how people would install dependencies
> for software that is not package that would also set the
> "is_auto_removable" flag in the apt cache to True? I can't think of a
> situation like this.

I had the opposite situation in my mind. People would remove packages
which are not auto removable, like ubuntu-desktop (for example because
something ubuntu-desktop depends on is acting badly) and then many
package in ubuntu-desktop's dependency change become auto removable:

$ sudo apt-get remove ubuntu-desktop
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  a11y-profile-manager-indicator activity-log-manager adium-theme-ubuntu
  aisleriot app-install-data-partner apturl apturl-common baobab bluez-cups
...
  xorg
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED:
  ubuntu-desktop
0 upgraded, 0 newly installed, 1 to remove and 7 not upgraded.
After this operation, 46,1 kB disk space will be freed.
Do you want to continue? [Y/n]

It is a simpler problematic situation than the one I originally mentioned, u-u
would remove software which is probably in use, no additional software is
broken.

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https://bugs.launchpad.net/bugs/1624644

Title:
  By default settings unattended-upgrade is unable to automatically
  remove packages that become unused in conjunction with updating by
  other software.

Status in apt package in Ubuntu:
  New
Status in gnome-software package in Ubuntu:
  New
Status in unattended-upgrades package in Ubuntu:
  New
Status in update-manager package in Ubuntu:
  New
Status in apt source package in Artful:
  New
Status in gnome-software source package in Artful:
  New
Status in unattended-upgrades source package in Artful:
  New
Status in update-manager source package in Artful:
  New

Bug description:
  When using default settings for unattended-upgrade i.e.
  Unattended-Upgrade::Remove-Unused-Dependencies "false";
  # default "false"
  Unattended-Upgrade::Remove-New-Unused-Dependencies "true";
  # default "true"
  in configuration file /etc/apt/apt.conf.d/50unattended-upgrades,
  unattended-upgrade is unable to remove packages that become unused in conjunction with updating by other software such as update-manager or apt full-upgrade. This is because unattended-upgrade compares the list of unneeded packages before and after it upgrades packages to detect which packages are new unused ones.

  Consequently, if user installs new kernels using e.g. update-manager,
  the excessive kernels will not be removed by unattended-upgrade, and
  eventually (small) /boot will become full.

  Expected behavior: handle removing of unused packages differently at
  least until other package management software installed by default can
  handle removing of new unused packages.

  ProblemType: Bug
  DistroRelease: Ubuntu 16.04
  Package: unattended-upgrades 0.90
  ProcVersionSignature: Ubuntu 4.4.0-36.55-generic 4.4.16
  Uname: Linux 4.4.0-36-generic i686
  ApportVersion: 2.20.1-0ubuntu2.1
  Architecture: i386
  CurrentDesktop: XFCE
  Date: Sat Sep 17 11:28:44 2016
  InstallationDate: Installed on 2016-09-05 (11 days ago)
  InstallationMedia: Mythbuntu 16.04.1 LTS "Xenial Xerus" - Release i386 (20160719)
  PackageArchitecture: all
  SourcePackage: unattended-upgrades
  UpgradeStatus: No upgrade log present (probably fresh install)

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