Bug 522815 - Discover does not start until process is killed manually
Summary: Discover does not start until process is killed manually
Status: RESOLVED FIXED
Alias: None
Product: Discover
Classification: Applications
Component: discover (other bugs)
Version First Reported In: 6.7.2
Platform: NixOS Linux
: VHI normal
Target Milestone: ---
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2026-07-08 17:50 UTC by adarsy1
Modified: 2026-08-15 14:31 UTC (History)
5 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


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Description adarsy1 2026-07-08 17:50:47 UTC
DESCRIPTION
I have experienced this issue on Fedora Linux, Arch Linux, and NixOS.
Sometimes, I am unable to open KDE Discover without first killing the process using System Monitor.
I have KDE Discover pinned to my task manager, so I encounter this frequently.

STEPS TO REPRODUCE
1. Open KDE Discover
2. Close KDE Discover while it is loading
3. Try opening KDE Discover

OBSERVED RESULT
Cannot open KDE Discover until I manually kill it with System Monitor.

EXPECTED RESULT
Process kills itself after I try closing while it's loading.

SOFTWARE/OS VERSIONS
Operating System (available in the Info Center app, or by running `kinfo` in a terminal window):
KDE Plasma Version: 6.7.2
KDE Frameworks Version: 6.27.0
Qt Version: 6.11.1

ADDITIONAL INFORMATION
This happened on a NixOS installation I installed yesterday.
Comment 1 David Edmundson 2026-07-09 13:52:23 UTC
That means the old one did not quit properly. 

I attached gdb and got nothing interesting.
Comment 2 TraceyC 2026-07-10 00:25:43 UTC
This sounds the same as bug 507217, that one was linked to Snap and KNS

On any of your distros, if you run this, does Discover launch?

plasma-discover --backends flatpak-backend
Comment 3 adarsy1 2026-07-10 01:20:01 UTC
(In reply to TraceyC from comment #2)
> This sounds the same as bug 507217, that one was linked to Snap and KNS
> 
> On any of your distros, if you run this, does Discover launch?
> 
> plasma-discover --backends flatpak-backend

No
Comment 4 TraceyC 2026-07-14 20:40:31 UTC
Thanks. The developers will need to investigate.
Comment 5 klecho 2026-07-28 15:23:29 UTC
Re-ordering the package systems included, seems to workaround the problem.
On my Debian and Ubuntu the system monitor icon never manages to launch it, even though showing that there are updates available, just blocks it from starting, until the process killed.
Comment 6 TraceyC 2026-07-29 16:33:01 UTC
I found that there's an existing bug about this, so I'll merge this in with the older one. Please follow bug 522245 for updates.
In both cases, the steps to reproduce include closing Discover while it's loading.

*** This bug has been marked as a duplicate of bug 522245 ***
Comment 7 Oliver Beard 2026-08-15 14:10:43 UTC
Git commit a8b5538958594d90406aa0294d3934bcd06e7607 by Oliver Beard, on behalf of Aleix Pol.
Committed on 15/08/2026 at 14:03.
Pushed by olib into branch 'master'.

DiscoverObject: Address quitting with concurrent KJobs

We have a mechanism that disables random eventloops (KJobs) from
quitting Discover outside of the user's interaction (see
QCoreApplication::setQuitLockEnabled in discover/main.cpp).

It so happens that we would at times have KJobs running also _after_
Discover's window closes. See how on the reported bugs they often
describe it happening early in the startup process.

This patch restores the Q*Application::quitLockEnabled property so that
once Discover is with its task and we let go and QCoreApplication can
let these jobs finish and eventually quit.

It changes the DummyBackend to issue a KJob at the start to be able to
reproduce this problem and eventually its fix.
Related: bug 497419, bug 522245, bug 518264

M  +2    -0    discover/DiscoverObject.cpp
M  +22   -0    libdiscover/backends/DummyBackend/DummyBackend.cpp

https://invent.kde.org/plasma/discover/-/commit/a8b5538958594d90406aa0294d3934bcd06e7607
Comment 8 Oliver Beard 2026-08-15 14:31:42 UTC
Git commit 0d0a1d35c715838f585590d54a1a9d5b14cbd151 by Oliver Beard.
Committed on 15/08/2026 at 14:11.
Pushed by olib into branch 'Plasma/6.7'.

DiscoverObject: Address quitting with concurrent KJobs

We have a mechanism that disables random eventloops (KJobs) from
quitting Discover outside of the user's interaction (see
QCoreApplication::setQuitLockEnabled in discover/main.cpp).

It so happens that we would at times have KJobs running also _after_
Discover's window closes. See how on the reported bugs they often
describe it happening early in the startup process.

This patch restores the Q*Application::quitLockEnabled property so that
once Discover is with its task and we let go and QCoreApplication can
let these jobs finish and eventually quit.

It changes the DummyBackend to issue a KJob at the start to be able to
reproduce this problem and eventually its fix.
Related: bug 497419, bug 522245, bug 518264


(cherry picked from commit a8b5538958594d90406aa0294d3934bcd06e7607)

Co-authored-by: Aleix Pol <aleixpol@kde.org>

M  +2    -0    discover/DiscoverObject.cpp
M  +22   -0    libdiscover/backends/DummyBackend/DummyBackend.cpp

https://invent.kde.org/plasma/discover/-/commit/0d0a1d35c715838f585590d54a1a9d5b14cbd151