when you have "world clocks" configured (e.g. from the Gnome Clocks application), Gnome Shell crashes on login, resulting in a login loop

This seems to happen both when you have world clocks configured before upgrading from cosmic to disco, as well as when configuring them after upgrading.

Thank you for taking the time to report this bug and helping to make Ubuntu better. It sounds like some part of the system has crashed. To help us find the cause of the crash please follow these steps:

1. Look in /var/crash for crash files and if found run:
    ubuntu-bug YOURFILE.crash
Then tell us the ID of the newly-created bug.

2. If step 1 failed then look at https://errors.ubuntu.com/user/ID where ID is the content of file /var/lib/whoopsie/whoopsie-id on the machine. Do you find any links to recent problems on that page? If so then please send the links to us.

3. If step 2 also failed then apply the workaround from bug 994921, reboot, reproduce the crash, and retry step 1.

Please take care to avoid attaching .crash files to bugs as we are unable to process them as file attachments. It would also be a security risk for yourself.

what locations did you configure in gnome-clocks?
what's the output of that command
$ gsettings get orc.gnome.clocks world-clocks

Ok, confirmed and it's reported upstream and fixed in https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/518

(installing gnome-clocks and adding dusserdorf as a location triggers the issue)

You can workaround it by going to a VT and do
$ gsettings reset org.gnome.clocks world-clocks

This bug was fixed in the package gnome-shell - 3.32.2-1ubuntu1

---------------
gnome-shell (3.32.2-1ubuntu1) eoan; urgency=medium

  * Merge with Debian. Remaining changes:
    + Replace gnome-backgrounds dep with ubuntu-wallpapers and Suggests
      gnome-themes-standard-data, gnome-backgrounds
    + Add some Recommends:
      - ubuntu-session (| gnome-session) to have the ubuntu session available
      - xserver-xorg-legacy
      - yaru-theme-gnome-shell for the default ubuntu theming
    + Update debian/gbp.conf with Ubuntu settings
    + gnome-shell-common.install: Install Ubuntu mode
    + gnome-shell-common.prerm: Remove deprecated ubuntu theme alternative
    + ubuntu/desktop_detect.patch:
      - add caching for desktop detection to avoid querying the current
        desktop env variable as iterate through the list each time. For the
        time of the Shell process, we can expect this env variable to stay
        stable.
    + ubuntu/smarter_alt_tab.patch:
      - quick alt-tab (without showing up the switcher) switch only between
        the last window of the last 2 applications to be focused instead of
        raising all windows of those apps.
    + ubuntu/lightdm-user-switching.patch:
      - Allow user switching when using LightDM.
    + ubuntu/lock_on_suspend.patch
      - Respect Ubuntu's lock-on-suspend setting.
    + ubuntu/gdm.patch
      - as gdm is system-wide and not session-wide, ensure gdm has an ubuntu
        styling by default, not impacting the gnome user session though.
    + ubuntu/background_login.patch
      - Change default background color as we modified the default GDM color
        for our ubuntu session. Change it as well here, still applying the
        background noise loading.
    + ubuntu/gdm_alternatives.patch
      - Add support for GDM3 theme alternatives
    + ubuntu/block_mode_extension_update.patch
      - Don't allow ubuntu mode extension to update
    + optional-hot-corner.patch
      - enable patch proposed by upstream developer already in package (but
        not in series) to add a settings for optional hot corner activation.
    + volume-Add-back-sound-feedback-on-scroll.patch
      - Fix regression causing missing feedback on volume slider scroll
    + main-show-an-error-message-on-gnome-shell-crash.patch,
      global-make-possible-to-set-debug-flags-dynamically.patch,
      main-increase-the-granularity-of-backtraces-in-SHELL_DEBU.patch,
      main-add-backtrace-crashes-all-and-backtrace-all.patch,
      sessionMode-add-support-for-debugFlags-parameter.patch:
      - Improve debug JS tracing for crash reports
    + st-scroll-view-Handle-the-case-where-scrollbars-are-NULL.patch,
      st-scroll-view-Remove-scrollbars-references-on-dispose.patch:
      - Fix crash on theme changes
    + ubuntu/search-call-XUbuntuCancel-method-on-providers-when-no-dat.patch:
      - stop searches when requested from UI
    + magnifier-Show-cursor-when-magnifier-is-enabled-and-scale.patch:
      - Show monitor scaled cursor when magnifier is enabled

gnome-shell (3.32.2-1) experimental; urgency=medium

  * New upstream release
    - Fix ellipsization in dialog subtitles/bodies (LP: #1809788)
    - Don't ...

Hello Jan, or anyone else affected,

Accepted gnome-shell into disco-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/gnome-shell/3.32.2-2ubuntu1~ubuntu19.04.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-disco to verification-done-disco. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-disco. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

I tested gnome-shell 3.32.2-2ubuntu1~ubuntu19.04.1 from disco-proposed and I had no problem to login, so it seems to be fixed.

The version of gnome-shell in the proposed pocket of Disco that was purported to fix this bug report has been removed because one or more bugs that were to be fixed by the upload have failed verification and been in this state for more than 10 days.

Did I miss something?

The verification of the Stable Release Update for gnome-shell has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.

This bug was fixed in the package gnome-shell - 3.32.2-2ubuntu1~ubuntu19.04.1

---------------
gnome-shell (3.32.2-2ubuntu1~ubuntu19.04.1) disco; urgency=medium

  * No-change SRU backport from eoan to disco. (LP: #1834517)

gnome-shell (3.32.2-2ubuntu1) eoan; urgency=medium

  * Merge with Debian. Remaining changes:
    + Replace gnome-backgrounds dep with ubuntu-wallpapers and Suggests
      gnome-themes-standard-data, gnome-backgrounds
    + Add some Recommends:
      - ubuntu-session (| gnome-session) to have the ubuntu session available
      - xserver-xorg-legacy
      - yaru-theme-gnome-shell for the default ubuntu theming
    + Update debian/gbp.conf with Ubuntu settings
    + gnome-shell-common.install: Install Ubuntu mode
    + gnome-shell-common.prerm: Remove deprecated ubuntu theme alternative
    + ubuntu/desktop_detect.patch:
      - add caching for desktop detection to avoid querying the current
        desktop env variable as iterate through the list each time. For the
        time of the Shell process, we can expect this env variable to stay
        stable.
    + ubuntu/smarter_alt_tab.patch:
      - quick alt-tab (without showing up the switcher) switch only between
        the last window of the last 2 applications to be focused instead of
        raising all windows of those apps.
    + ubuntu/lightdm-user-switching.patch:
      - Allow user switching when using LightDM.
    + ubuntu/lock_on_suspend.patch
      - Respect Ubuntu's lock-on-suspend setting.
    + ubuntu/gdm.patch
      - as gdm is system-wide and not session-wide, ensure gdm has an ubuntu
        styling by default, not impacting the gnome user session though.
    + ubuntu/background_login.patch
      - Change default background color as we modified the default GDM color
        for our ubuntu session. Change it as well here, still applying the
        background noise loading.
    + ubuntu/gdm_alternatives.patch
      - Add support for GDM3 theme alternatives
    + ubuntu/block_mode_extension_update.patch
      - Don't allow ubuntu mode extension to update
    + optional-hot-corner.patch
      - enable patch proposed by upstream developer already in package (but
        not in series) to add a settings for optional hot corner activation.
    + volume-Add-back-sound-feedback-on-scroll.patch
      - Fix regression causing missing feedback on volume slider scroll
    + main-show-an-error-message-on-gnome-shell-crash.patch,
      global-make-possible-to-set-debug-flags-dynamically.patch,
      main-increase-the-granularity-of-backtraces-in-SHELL_DEBU.patch,
      main-add-backtrace-crashes-all-and-backtrace-all.patch,
      sessionMode-add-support-for-debugFlags-parameter.patch:
      - Improve debug JS tracing for crash reports
    + st-scroll-view-Handle-the-case-where-scrollbars-are-NULL.patch,
      st-scroll-view-Remove-scrollbars-references-on-dispose.patch:
      - Fix crash on theme changes
    + ubuntu/search-call-XUbuntuCancel-method-on-providers-when-no-dat.patch:
      - stop searches when requested from UI
    + magnifier-Show-cursor-when-magnifier-is-enabled-and-scale.patch:
      - Show monitor scaled cursor when magnifier is enabled

gnome-shell ...