[Bug 1771894] Re: /usr/bin/update-manager:TypeError:<lambda>:on_button_install_clicked:start_install:_start_pane:start:unwind_generator

[Launchpad Bug Tracker]

This bug was fixed in the package update-manager - 1:16.04.15

---------------
update-manager (1:16.04.15) xenial; urgency=medium

  * Keep or delete packages after looping over all of them.
    This prevents the resolver from changing the packages in the loop resulting
    in not keeping some phased packages back from being upgraded. (LP: #1072136)
  * Stop lazy import of InstallBackends.
    Lazy imports made update-manager crash when an update-manager
    update changed the backend API and an updated incompatible backend
    was loaded to the not updated running update-manager process. (LP: #1795898)
  * Cancel transaction on exit only when Cancel button is active.
    Also ignore exception when cancellation fails. (LP: #1790670)
  * Make commit()'s last parameter optional for avoiding crash on upgrade
    (LP: #1771894)

 -- Balint Reczey <rbalint at ubuntu.com>  Thu, 04 Oct 2018 21:51:10 +0200

** Changed in: update-manager (Ubuntu Xenial)
       Status: Fix Committed => Fix Released

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https://bugs.launchpad.net/bugs/1771894

Title:
  /usr/bin/update-
  manager:TypeError:<lambda>:on_button_install_clicked:start_install:_start_pane:start:unwind_generator

Status in update-manager package in Ubuntu:
  Invalid
Status in update-manager source package in Xenial:
  Fix Released

Bug description:
  [Impact]

  The backend API change made update-manager crash when the updated
  incompatible backend was loaded to the not updated running update-
  manager process.

  The issue causes crashes upon update-manager updates harming the
  upgrade experience for users.

  The fix avoids lazy loading of the backend modules but still honors
  the backend selection options.

  [Test Case]


  1. Start with a fully upgraded system and downgrade a few packages to let u-m upgrade them and also downgrade update-manager to 1:16.04.12 or earlier:
  $ sudo eatmydata apt install -y --allow-downgrades gnome-software=3.28.1-0ubuntu4 gnome-software-common=3.28.1-0ubuntu4
  $ sudo apt install update-manager=1:16.04.12 update-manager-core=1:16.04.12 python3-update-manager=1:16.04.12

  2. Start u-m with:
   $ update-manager --no-update

  3. Upgrade update-manager to a still not fixed version to observe the crash:
  $ sudo apt install update-manager=1:16.04.14 update-manager-core=1:16.04.14 python3-update-manager=1:16.04.14

  ... or to the fixed version to a see the crash not happening in step
  4:

  $ sudo apt install update-manager=1:16.04.15 update-manager-
  core=1:16.04.15 python3-update-manager=1:16.04.15

  
  4. Press "Install Now" on u-m GUI.
   The fixed u-m will successfully perform the installation, the unfixed one will fail with:
  TypeError: commit() missing 1 required positional argument: 'pkgs_remove'

  [Regression Potential]

  The change to the backend API could cause u-m not able to remove
  unused kernels, but in my testing this feature still worked.

  [Original Bug Text]

  The Ubuntu Error Tracker has been receiving reports about a problem regarding update-manager.  This problem was most recently seen with package version 1:18.04.11, the problem page at https://errors.ubuntu.com/problem/310b9890e139c17b61faeee8f50078909283794e contains more details, including versions of packages affected, stacktrace or traceback, and individual crash reports.
  If you do not have access to the Ubuntu Error Tracker and are a software developer, you can request it at http://forms.canonical.com/reports/.

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