Bug 495115

The ID of QStandardItemModel changes on every launch:
plasma-discover
libs QList("/usr/lib/x86_64-linux-gnu/qt6/plugins", "/usr/bin")
org.kde.plasma.libdiscover: OdrsReviewsBackend: Fetch ratings: true
adding empty sources model QStandardItemModel(0x5de8ff8ece80)
^C

I'm seeing this too, very consistently.  It appears to be the same as #481993, but that one has been marked fixed (albeit with a hack).  

As in that bug, plasma-discover hangs if I do not specify any backends. But it succeeds if I specify all the backends.  But the order matters.

        $ plasma-discover                                             
        libs QList("/usr/lib/x86_64-linux-gnu/qt6/plugins", "/usr/bin")
        org.kde.plasma.libdiscover: OdrsReviewsBackend: Fetch ratings: false
        adding empty sources model QStandardItemModel(0x5bf3e89f78c0)
        ^C


When I specified the backends to load and included all of them, it worked.

        $ plasma-discover --listbackends
        Available backends:
        * packagekit-backend
        * snap-backend
        * fwupd-backend
        * flatpak-backend
        * kns-backend

        $ plasma-discover --backends packagekit,fwupd,kns,snap,flatpak
        org.kde.plasma.libdiscover: OdrsReviewsBackend: Fetch ratings: false
        adding empty sources model QStandardItemModel(0x5a420195d800)
        qrc:/qt/qml/org/kde/kirigami/dialogs/Dialog.qml:344:18: QML ScrollView: Binding loop detected for property "calculatedImplicitWidth"
        qrc:/qt/qml/org/kde/kirigami/dialogs/Dialog.qml:344:18: QML ScrollView: Binding loop detected for property "calculatedImplicitHeight"
        qrc:/qt/qml/org/kde/kirigami/dialogs/Dialog.qml:401:33: QML Binding: Binding loop detected for property "value"
        qrc:/qt/qml/org/kde/discover/qml/BrowsingPage.qml:17:1: QML BrowsingPage: Created graphical object was not placed in the graphics scene.


If I specify the backends in the order they were listed, it fails the same as before:

        $ plasma-discover --backends packagekit,snap,fwupd,flatpak,kns
        org.kde.plasma.libdiscover: OdrsReviewsBackend: Fetch ratings: false
        adding empty sources model QStandardItemModel(0x62a8c78bd620)
        ^C

Same behavior after upgrade to 24.04 LTS, does not load. 
Running from command line does not open anything or shows any errors

Actually, it shows:
$ plasma-discover
libs QList("/usr/lib/x86_64-linux-gnu/qt6/plugins", "/usr/bin")
org.kde.plasma.libdiscover: OdrsReviewsBackend: Fetch ratings: true
adding empty sources model QStandardItemModel(0x62d3a8610650)

Launching second time does not show any errors, but keeps hanging until CTRL+C.

OK, this is funny (or not). I have installed the debug symbols:
$ pkcon install plasma-discover-dbgsym
Resolving                               [=========================]
Testing changes                         [=========================]
Finished                                [                         ] (0%)
The following packages have to be installed:
plasma-discover-dbgsym-6.2.3-0zneon+24.04+noble+release+build8.amd64   debug symbols for plasma-discover
Proceed with changes? [N/y] y

[=========================]
Installing                              [=========================]
Waiting for authentication              [=========================]
Loading cache                           [=========================]
Downloading packages                    [=========================]
Running                                 [=========================]
Finished                                [=========================]

Then suddenly Discover started. Until I closed it again and now I am unable to start it again...

Created attachment 175933 [details]
strace log

strace log

as confirmed by other users:
https://www.reddit.com/r/kde/comments/1b5ludx/discover_doesnt_start_up_on_plasma_6_in_kde_neon/

OK, related to:
https://bugs.kde.org/show_bug.cgi?id=481993
or possibly a duplicate.

Solution recommended here works:
https://bugs.kde.org/show_bug.cgi?id=481993#c4

these work for me when running from command line:
plasma-discover --backends packagekit-backend
plasma-discover --backends flatpak-backend
plasma-discover --backends packagekit-backend,flatpak-backend

Since this bug is not resolved in the last KDE-Neon Jammy with Plasma 6.2.0, is there any fix available?
We have many users, who can't start Discover after upgrading from Plasma 6.1.5 to Plasma 6.2.0 last available versions in neons jammy repo.