SUMMARY Recent update via pkcon refresh+update earlier today borked my plasmashell due to an unresolved symbol PluginMetaData::value(), which is supposed to be provided by libkf5coreaddons. Running apt list --installed, I saw I had libkf5plasma5 5.88 installed, but libkf5coreaddons5 was stuck on 5.86, and another pkcon refresh+update would not update it. It's there in the repositories, though, and I was able to install the .deb files manually which fixed the problem for me (see below). Note: I forgot to try apt update+upgrade; not sure if that would have made a difference. STEPS TO REPRODUCE 1. Update KDE Neon User 20.04 (sudo pkcon refresh && sudo pkcon update) 2. Reboot OBSERVED RESULT * libkf5coreaddons5 gets stuck on version 5.86 * The login screen reports the following error: file:///user/share/sddm/themes/breeze/Main.qml:14:1: plugin cannot be loaded for module "org.kde.plasma.core": Cannot load library /usr/lib/x86_64-linux-gnu/qt5/qml/org/kde/plasma/core/libcorebindingsplugin.so: (/usr/lib/x86_64-linux-gnu/libKF5Plasma.so.5: undefined symbol: _ZNK15KPluginMetaData5valueERK7QStringRK11QStringList) * Attempting to log in hangs. * Opening another screen with Ctrl+Alt+F2 and running "plasmashell" directly from the terminal, we get that same "undefined symbol" error as above. EXPECTED RESULT * libkf5coreaddons5 should update to 5.88 * Plasmashell should launch like normal SOFTWARE/OS VERSIONS Linux/KDE Plasma: KDE neon User 20.04 KDE Plasma Version: 5.23.3 KDE Frameworks Version: 5.88.0 Qt Version: 5.15.3 ADDITIONAL INFORMATION Fixed my plasmashell by forcing Ubuntu to install the correct version of KCoreAddons 5.88: sudo pkcon refresh apt download libkf5coreaddons-data=5.88.0-0xneon+20.04+focal+release+build32 libkf5coreaddons-dev=5.88.0-0xneon+20.04+focal+release+build32 libkf5coreaddons-dev-bin=5.88.0-0xneon+20.04+focal+release+build32 libkf5coreaddons-dev-bin=5.88.0-0xneon+20.04+focal+release+build32 libkf5coreaddons5=5.88.0-0xneon+20.04+focal+release+build32 sudo dpkg -i libkf5coreaddons-data_5.88.0-0xneon+20.04+focal+release+build32_all.deb libkf5coreaddons-dev_5.88.0-0xneon+20.04+focal+release+build32_amd64.deb libkf5coreaddons-dev-bin_5.88.0-0xneon+20.04+focal+release+build32_amd64.deb libkf5coreaddons5_5.88.0-0xneon+20.04+focal+release+build32_amd64.deb During installation, I saw the following warning from dpkg: warning: downgrading libkf5coreaddons-dev:amd64 from 5:5.86.0-0xneon+20.04+focal+release+build25 to 5.88.0-0xneon+20.04+focal+release+build32 which I think means dpkg thinks the version string "5:5.86.0" is newer than "5.88".
Created attachment 143651 [details] Screenshot on login I have the same problem. I use working snapshots in my sysmetm and I can help with reproduce
Can you paste the output of apt-cache policy libkf5coreaddons-dev and cat /etc/apt/preferences.d/50-kcoreaddons
I've fixed this issue by next command: sudo apt install libkf5coreaddons5=5.88.* libkf5coreaddons-data=5.88.* -V
@Jonathan Riddell sure: (Note this is with 5.88 installed. I dunno how to go back to 5.86 without manually installing that version, which I think would mess up the output of apt-cache policy?) $ apt-cache policy libkf5coreaddons-dev libkf5coreaddons-dev: Installed: 5.88.0-0xneon+20.04+focal+release+build32 Candidate: 5.88.0-0xneon+20.04+focal+release+build32 Version table: *** 5.88.0-0xneon+20.04+focal+release+build32 500 500 http://archive.neon.kde.org/user focal/main amd64 Packages 100 /var/lib/dpkg/status 5.87.0-0xneon+20.04+focal+release+build31 500 500 http://archive.neon.kde.org/user focal/main amd64 Packages 5.86.0-0xneon+20.04+focal+release+build27 500 500 http://archive.neon.kde.org/user focal/main amd64 Packages 5.85.0-0xneon+20.04+focal+release+build25 500 500 http://archive.neon.kde.org/user focal/main amd64 Packages 5.84.0-0xneon+20.04+focal+release+build24 500 500 http://archive.neon.kde.org/user focal/main amd64 Packages 5.68.0-0ubuntu1 500 500 http://us.archive.ubuntu.com/ubuntu focal/universe amd64 Packages $ I don't have the file /etc/apt/preferences.d/50-kcoreaddons: $ find /etc/apt/preferences.d | grep -i 'core.*addon' $ One thing I noticed is "apt download" surprisingly downloads the latest version: $ apt download libkf5coreaddons5 libkf5coreaddons-data libkf5coreaddons-dev libkf5coreaddons-dev-bin Get:1 http://archive.neon.kde.org/user focal/main amd64 libkf5coreaddons-data all 5.88.0-0xneon+20.04+focal+release+build32 [148 kB] Get:2 http://archive.neon.kde.org/user focal/main amd64 libkf5coreaddons-dev amd64 5.88.0-0xneon+20.04+focal+release+build32 [106 kB] Get:3 http://archive.neon.kde.org/user focal/main amd64 libkf5coreaddons-dev-bin amd64 5.88.0-0xneon+20.04+focal+release+build32 [41.0 kB] Get:4 http://archive.neon.kde.org/user focal/main amd64 libkf5coreaddons5 amd64 5.88.0-0xneon+20.04+focal+release+build32 [247 kB] Fetched 541 kB in 1s (552 kB/s) $
Jonathan apt-cache policy libkf5coreaddons-dev : libkf5coreaddons5: Installed: 5:5.86.0-0xneon+20.04+focal+release+build26 Candidate: 5:5.86.0-0xneon+20.04+focal+release+build26 Version table: *** 5:5.86.0-0xneon+20.04+focal+release+build26 100 100 /var/lib/dpkg/status 5.88.0-0xneon+20.04+focal+release+build32 500 500 https://origin.archive.neon.kde.org/user focal/main amd64 Packages 5.87.0-0xneon+20.04+focal+release+build31 500 500 https://origin.archive.neon.kde.org/user focal/main amd64 Packages 5.86.0-0xneon+20.04+focal+release+build27 500 500 https://origin.archive.neon.kde.org/user focal/main amd64 Packages 5.85.0-0xneon+20.04+focal+release+build25 500 500 https://origin.archive.neon.kde.org/user focal/main amd64 Packages 5.84.0-0xneon+20.04+focal+release+build24 500 500 https://origin.archive.neon.kde.org/user focal/main amd64 Packages 5.68.0-0ubuntu1 500 500 http://ua.archive.ubuntu.com/ubuntu focal/universe amd64 Packages Folder /etc/apt/preferences.d/ is empty
You are missing the file /etc/apt/preferences.d/50-kcoreaddons which comes from the package neon-settings-2 do you have that package installed?
I don't have that installed, but it's available in apt.
Here's what happens when I try to install it. daddesio@daddesio-HP-EliteDesk-800-G2-TWR:~$ sudo apt install neon-settings-2 [sudo] password for daddesio: Reading package lists... Done Building dependency tree Reading state information... Done Starting pkgProblemResolver with broken count: 1 Starting 2 pkgProblemResolver with broken count: 1 Investigating (0) kubuntu-settings-desktop:amd64 < 1:20.04.9 @ii mK Ib > Broken kubuntu-settings-desktop:amd64 Conflicts on neon-settings:amd64 < none @rc H > Conflicts//Breaks against version 0.0+p18.04+git20200805.1230 for neon-settings but that is not InstVer, ignoring Conflicts//Breaks against version 0.4+p20.04+trelease+git20210817.1407 for neon-settings-2 but that is not InstVer, ignoring Conflicts//Breaks against version 0.4+p20.04+trelease+git20210818.1110 for neon-settings-2 but that is not InstVer, ignoring Conflicts//Breaks against version 0.4+p20.04+trelease+git20210909.0907 for neon-settings-2 but that is not InstVer, ignoring Considering neon-settings-2:amd64 9999 as a solution to kubuntu-settings-desktop:amd64 1 Removing kubuntu-settings-desktop:amd64 rather than change neon-settings:amd64 Investigating (0) kubuntu-desktop:amd64 < 1.398 @ii mK NPb Ib > Broken kubuntu-desktop:amd64 Depends on kubuntu-settings-desktop:amd64 < 1:20.04.9 @ii mR > Considering kubuntu-settings-desktop:amd64 1 as a solution to kubuntu-desktop:amd64 0 Removing kubuntu-desktop:amd64 rather than change kubuntu-settings-desktop:amd64 Done The following package was automatically installed and is no longer required: libkf5coreaddons-doc Use 'sudo apt autoremove' to remove it. The following packages will be REMOVED: kubuntu-desktop kubuntu-settings-desktop The following NEW packages will be installed: neon-settings-2 0 upgraded, 1 newly installed, 2 to remove and 0 not upgraded. Need to get 40.7 kB of archives. After this operation, 494 kB disk space will be freed. Do you want to continue? [Y/n] n Abort. Note that I manually installed kubuntu-desktop last year, since my system broke during the Neon 18.04 -> Neon 20.04 update and the easiest "fix" at the time was manually installing kubuntu-desktop (which I thought was a metapackage that reinstalled all the KDE apps).
Ah yes, after installing neon-settings-2 then doing another pkcon refresh+update, I see: $ sudo pkcon update Getting updates [=========================] Finished [=========================] Loading cache [=========================] Testing changes [=========================] Finished [ ] (0%) The following packages have to be downgraded: libkf5coreaddons-doc-5:5.86.0-0xneon+20.04+focal+release+build26.all KDE Frameworks 5 addons to QtCore (documentation) The following packages have to be updated: libnetplan0-0.103-0ubuntu5~20.04.3.amd64 YAML network configuration abstraction runtime library netplan.io-0.103-0ubuntu5~20.04.3.amd64 YAML network configuration abstraction for various backends rsync-3.1.3-8ubuntu0.1.amd64 fast, versatile, remote (and local) file-copying tool Proceed with changes? [N/y which looks like it will successfully update (or what it calls "downgrade") "5:5.86.0" to "5.88.0".
Okay, I installed neon-settings-2 and uninstalled kubuntu-desktop, and my system still boots and works like normal. Thanks for your help, @Jonathan Riddell
Hmm, I wonder: Was neon-settings-2 available in Neon since day one? Did it have the file /etc/apt/preferences.d/50-kcoreaddons since day one? What happens if someone updates an old system and immediately reboots - could they potentially experience this error? Don't you need two rounds of "pkcon refresh+update" - the first one to install the file, and the second one to actually "downgrade" to 5.88?
(In reply to Andrew D'Addesio from comment #11) > Hmm, I wonder: Was neon-settings-2 available in Neon since day one? Did it > have the file /etc/apt/preferences.d/50-kcoreaddons since day one? > > What happens if someone updates an old system and immediately reboots - > could they potentially experience this error? Don't you need two rounds of > "pkcon refresh+update" - the first one to install the file, and the second > one to actually "downgrade" to 5.88? 5:5 is not longer available as per your policy output so there is no way and old system ever ends up with it