*** Bug 419257 has been marked as a duplicate of this bug. ***

*** Bug 420393 has been marked as a duplicate of this bug. ***

Could you try running plasma-autostart-list? It's a test application built by plasma-workspace.

It could help us see where plasma gets the idea of starting discover.

I get something like this:
$ ./bin/plasma-autostart-list
phase: 0
- xembedsniproxy /home/apol/devel/kde5/etc/xdg/autostart/xembedsniproxy.desktop
- org.kde.plasmashell /home/apol/devel/kde5/etc/xdg/autostart/org.kde.plasmashell.desktop
- polkit-kde-authentication-agent-1 /home/apol/devel/kde5/etc/xdg/autostart/polkit-kde-authentication-agent-1.desktop
- kaccess /home/apol/devel/kde5/etc/xdg/autostart/kaccess.desktop

phase: 1
- gmenudbusmenuproxy /home/apol/devel/kde5/etc/xdg/autostart/gmenudbusmenuproxy.desktop
- org.kde.discover.notifier /home/apol/devel/kde5/etc/xdg/autostart/org.kde.discover.notifier.desktop
- org.kde.kdeconnect.daemon /home/apol/devel/kde5/etc/xdg/autostart/org.kde.kdeconnect.daemon.desktop
- pulseaudio /etc/xdg/autostart/pulseaudio.desktop

phase: 2
- org.kde.yakuake /home/apol/.config/autostart/org.kde.yakuake.desktop
- tracker-store /etc/xdg/autostart/tracker-store.desktop, startAfter:panel
- snap-userd-autostart /etc/xdg/autostart/snap-userd-autostart.desktop
- powerdevil /home/apol/devel/kde5/etc/xdg/autostart/powerdevil.desktop
- gnome-shell-overrides-migration /etc/xdg/autostart/gnome-shell-overrides-migration.desktop
- geoclue-demo-agent /etc/xdg/autostart/geoclue-demo-agent.desktop

Here's what I have:


phase: 0
- pam_kwallet_init /etc/xdg/autostart/pam_kwallet_init.desktop
- org.kde.plasmashell /home/nate/kde/usr/etc/xdg/autostart/org.kde.plasmashell.desktop
- kaccess /home/nate/kde/usr/etc/xdg/autostart/kaccess.desktop
- polkit-kde-authentication-agent-1 /home/nate/kde/usr/etc/xdg/autostart/polkit-kde-authentication-agent-1.desktop
- xembedsniproxy /home/nate/kde/usr/etc/xdg/autostart/xembedsniproxy.desktop
- baloo_file /home/nate/kde/usr/etc/xdg/autostart/baloo_file.desktop

phase: 1
- xdg-user-dirs /etc/xdg/autostart/xdg-user-dirs.desktop
- pulseaudio /etc/xdg/autostart/pulseaudio.desktop
- gmenudbusmenuproxy /home/nate/kde/usr/etc/xdg/autostart/gmenudbusmenuproxy.desktop
- org.kde.kdeconnect.daemon /home/nate/kde/usr/etc/xdg/autostart/org.kde.kdeconnect.daemon.desktop
- org.kde.discover.notifier /home/nate/kde/usr/etc/xdg/autostart/org.kde.discover.notifier.desktop

phase: 2
- hplip-systray /etc/xdg/autostart/hplip-systray.desktop
- xbindkeys /home/nate/.config/autostart/xbindkeys.desktop
- z-displaycal-apply-profiles /home/nate/.config/autostart/z-displaycal-apply-profiles.desktop
- powerdevil /home/nate/kde/usr/etc/xdg/autostart/powerdevil.desktop
- kup-daemon /home/nate/kde/usr/etc/xdg/autostart/kup-daemon.desktop, startAfter:panel
- SpiderOakONE /home/nate/.config/autostart/SpiderOakONE.desktop
- ibus-autostart /etc/xdg/autostart/ibus-autostart.desktop, startAfter:panel
- telegramdesktop /home/nate/.config/autostart/telegramdesktop.desktop



I guess the notifier causes all of Discover to get launched?

Git commit 0012f339a6cb5fbfd51ad1747373a081a88959c2 by Aleix Pol.
Committed on 22/05/2020 at 18:06.
Pushed by apol into branch 'Plasma/5.18'.

Disable session management for Discover

M  +1    -0    discover/main.cpp

https://invent.kde.org/plasma/discover/commit/0012f339a6cb5fbfd51ad1747373a081a88959c2

*** Bug 428072 has been marked as a duplicate of this bug. ***

Clearly not fixed. :( Can reproduce myself.

Git commit 718e6fdc1019f2a3153b1c45f79b90ec598a826d by Nate Graham.
Committed on 29/10/2020 at 20:42.
Pushed by ngraham into branch 'master'.

Disable session management properly

The attribute needs to be set before the QGuiApplication is created or
else it doesn't have any effect.

M  +3    -1    discover/main.cpp

https://invent.kde.org/plasma/discover/commit/718e6fdc1019f2a3153b1c45f79b90ec598a826d

Git commit d513a424dc7f35246e712359e0807d01431da579 by Nate Graham.
Committed on 29/10/2020 at 20:43.
Pushed by ngraham into branch 'Plasma/5.20'.

Disable session management properly

The attribute needs to be set before the QGuiApplication is created or
else it doesn't have any effect.
(cherry picked from commit 718e6fdc1019f2a3153b1c45f79b90ec598a826d)

M  +3    -1    discover/main.cpp

https://invent.kde.org/plasma/discover/commit/d513a424dc7f35246e712359e0807d01431da579

I have seen this behavior several times on Kubuntu 20.10 (plasma-discover 5.19.5)

When this happens, it is always after DiscoverNotifier has notified about updates, I have used it to launch discover, installed updates, and closed discover when it has completed during the previous KDE session. I notice that most of the time after closing it, there is a "stuck" "plasma-discover --mode update" process hanging around.

So I think the root cause is not some bug with the session management/restoration functionality, but with a hang in plasma-discover at close (the window is gone so the user thinks it has exited, but the process remains and is still registered with the session).

I will try to catch a stacktrace next time I see it.

No need, it was already fixed in Plasma 5.20.3. :)

I understand that the fix was to disable session support in discover though, am I mistaken? 

If session restoration is enabled, and discover was open when the session was exited, it should be restored next time..

I was able to catch the issue (in my case) that leads to discover being restored on login again, please see Bug 431892. Perhaps it is the root cause for others.

*** Bug 435683 has been marked as a duplicate of this bug. ***