Does it work if you uninstall qqc2-desktop-style?

I can confirm the above-mentioned issue. Uninstalling qqc2-desktop-style does not solve it. In fact, starting plasma-discover from the console gives

Adding empty sources model QStandardItemModel(0x55e521fad920)
Segmentation fault (core dumped)

(In reply to Frank Kruger from comment #2)
> I can confirm the above-mentioned issue. Uninstalling qqc2-desktop-style
> does not solve it.

Ok, then I can only suggest trying to install discover 5.16.2 from KDE:Frameworks5 for now.
Maybe it is fixed already?
Otherwise an upstream bug report might be a good idea.

Uninstalling qqc2-desktop-style gives me the following error when launching plasma-discover in Konsole:
invalid kns backend! "/usr/share/knsrcfiles/ksysguard.knsrc" because: "Config group not found! Check your KNS3 installation."
adding empty sources model QStandardItemModel(0x561cd80b9500)
Segmentation fault (core dumped)

Uninstalling Discover (and backend pacakages) and then replacing them with the 5.16.2 packages from the KDE:Frameworks5 repo gives this error on launch:
file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:62: TypeError: Cannot read property 'selectedText' of null
file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:70: TypeError: Cannot read property 'selectedText' of null
file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:78: TypeError: Cannot read property 'canPaste' of null
adding empty sources model QStandardItemModel(0x557a07e8b5d0)
Segmentation fault (core dumped)

I've searched on Google for anyone else having similar problems, but the only ones I can find are from more than a year ago when Plasma 5.12 came out. Searching KDE forums and KDE bugs draws a blank, so at the moment I think it is openSUSe specific.
https://old.reddit.com/r/openSUSE/comments/c5hu8j/fresh_install_tumbleweed_discover_crashes_on/
https://forums.opensuse.org/showthread.php/536562-Discover

(In reply to Ms Hmm from comment #4)
> Uninstalling Discover (and backend pacakages) and then replacing them with
> the 5.16.2 packages from the KDE:Frameworks5 repo gives this error on launch:
> file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/
> MobileTextActionsToolBar.qml:62: TypeError: Cannot read property
> 'selectedText' of null
> file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/
> MobileTextActionsToolBar.qml:70: TypeError: Cannot read property
> 'selectedText' of null
> file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/
> MobileTextActionsToolBar.qml:78: TypeError: Cannot read property 'canPaste'
> of null
> adding empty sources model QStandardItemModel(0x557a07e8b5d0)
> Segmentation fault (core dumped)
Ok, the QML errors are the same as before, probably because you reinstalled qqc2-desktop-style, but that doesn't seem to be the reason for the crash anyway.

> I've searched on Google for anyone else having similar problems, but the
> only ones I can find are from more than a year ago when Plasma 5.12 came
> out. Searching KDE forums and KDE bugs draws a blank, so at the moment I
> think it is openSUSe specific.
That's not necessarily an indication for an openSUSE specific problem though, especially on Tumbleweed. Most distributions are not as up-to-date... ;-)

I'd still suggest filing an upstream bug report.

This seems to be relevant though:
Adding empty sources model QStandardItemModel(0x55e521fad920)

(In reply to Ms Hmm from comment #4)
> I've searched on Google for anyone else having similar problems, but the
> only ones I can find are from more than a year ago when Plasma 5.12 came
> out. Searching KDE forums and KDE bugs draws a blank, so at the moment I
> think it is openSUSe specific.
> https://old.reddit.com/r/openSUSE/comments/c5hu8j/
> fresh_install_tumbleweed_discover_crashes_on/
> https://forums.opensuse.org/showthread.php/536562-Discover

Others are also hit by this isssue: https://www.reddit.com/r/openSUSE/comments/c5hu8j/fresh_install_tumbleweed_discover_crashes_on/

Well, the only change in 5.16.1 that seems relevant is this:
https://cgit.kde.org/discover.git/commit/?id=67b313bdd6472e79e3d500f8b32d0451c236ce84

Can you please try discover from here that has this reverted?
https://download.opensuse.org/repositories/home:/wolfi323:/boo1139463/openSUSE_Tumbleweed/

(In reply to Wolfgang Bauer from comment #7)
> Well, the only change in 5.16.1 that seems relevant is this:
> https://cgit.kde.org/discover.git/commit/
> ?id=67b313bdd6472e79e3d500f8b32d0451c236ce84
> 
> Can you please try discover from here that has this reverted?
> https://download.opensuse.org/repositories/home:/wolfi323:/boo1139463/
> openSUSE_Tumbleweed/

Unfortunately, it does not work for me. Same error messages as before.

Then I don't know, and it's probably caused by some other update.
Appstream maybe?

> That's not necessarily an indication for an openSUSE specific problem
> though, especially on Tumbleweed. Most distributions are not as
> up-to-date... ;-)

Fair point, although I did search for the bug on Arch Linux.

> I'd still suggest filing an upstream bug report.

I've now found an upstream bug report https://bugs.kde.org/show_bug.cgi?id=409195

FYI: With TW20190626 and after a reboot Discover is working again for me.

Still crashes here on 20190626

(In reply to Michael Pujos from comment #12)
> Still crashes here on 20190626

For the sake of curiosity, could you please install or uninstall discover-backend-fwupd and then restart Discover?

(In reply to Frank Kruger from comment #13)
> (In reply to Michael Pujos from comment #12)
> > Still crashes here on 20190626
> 
> For the sake of curiosity, could you please install or uninstall
> discover-backend-fwupd and then restart Discover?

Still crashing after uninstalling that package, and again after reinstalling it.

(In reply to Frank Kruger from comment #11)
> FYI: With TW20190626 and after a reboot Discover is working again for me.

Fresh install of TW20190626, Discover still present the issue.

An update, now discover is launching for some reason. I can't see any apps and now it complains about Appstream.

Here is the terminal output:

file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:62: TypeError: Cannot read property 'selectedText' of null
file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:70: TypeError: Cannot read property 'selectedText' of null
file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:78: TypeError: Cannot read property 'canPaste' of null
invalid kns backend! "/usr/share/knsrcfiles/ksysguard.knsrc" because: "Config group not found! Check your KNS3 installation."
adding empty sources model QStandardItemModel(0x55ef31dde230)
Could not open the AppStream metadata pool "Some components have been ignored: Los archivos de metadatos tienen errores: /var/cache/app-info/xmls/download.opensuse.org-oss.xml.gz, /var/cache/app-info/xmls/download.opensuse.org-non-oss.xml.gz"
no packages for "org.kde.okular-md"
no packages for "org.kde.okular-ooo"
no packages for "org.kde.plasma.quicklaunch"
no packages for "org.kde.plasma.weather"
no packages for "org.kde.plasma.systemmonitor.memory"
no packages for "org.kde.desktopcontainment"
no packages for "org.kde.plasma.networkmanagement"
no packages for "org.kde.plasma.systemloadviewer"
no packages for "org.kde.plasma.webbrowser"
no packages for "org.kde.plasma.clipboard"
no packages for "org.kde.okular-tiff"
no packages for "org.kde.plasma.pager"
no packages for "org.kde.okular-plucker"
no packages for "org.kde.plasma.showActivityManager"
no packages for "org.kde.plasma.notes"
no packages for "org.kde.okular-dvi"
no packages for "org.kde.okular-comicbook"
no packages for "org.kde.plasma.trash"
no packages for "org.kde.plasma.comic"
no packages for "org.kde.plasma.windowlist"
no packages for "org.kde.plasma.battery"
no packages for "org.kde.hunyango"
no packages for "org.kde.haenau"
no packages for "org.kde.okular-poppler"
no packages for "org.kde.plasma.lock_logout"
no packages for "org.kde.plasma.keyboardindicator"
no packages for "org.kde.paneltoolbox"
no packages for "org.kde.plasma.printmanager"
no packages for "org.kde.okular-xps"
no packages for "org.kde.plasma.grouping"
no packages for "org.kde.plasma.analogclock"
no packages for "org.kde.plasma.folder"
no packages for "org.kde.color"
no packages for "org.kde.image"
no packages for "org.kde.okular-epub"
no packages for "org.kde.okular-fax"
no packages for "org.kde.plasma.bluetooth"
no packages for "org.kde.plasma.systemmonitor.diskusage"
no packages for "org.kde.plasma.wacomtablet"
no packages for "org.kde.plasma.showdesktop"
no packages for "org.kde.okular-mobipocket"
no packages for "org.kde.plasma.diskquota"
no packages for "org.kde.plasma.systemtray"
no packages for "org.kde.plasma.calendar"
no packages for "org.gnome.cantarell"
no packages for "org.kde.plasma.systemmonitor.diskactivity"
no packages for "org.freedesktop.appstream.cli"
no packages for "org.kde.breezedark.desktop"
no packages for "org.kde.plasma.userswitcher"
no packages for "org.kde.plasma.systemmonitor.net"
no packages for "org.kde.plasma.desktop.emptyPanel"
no packages for "org.kde.desktoptoolbox"
no packages for "org.kde.okular-kimgio"
no packages for "org.kde.plasma.fuzzyclock"
no packages for "org.kde.plasma.kicker"
no packages for "org.kde.plasma_applet_dict"
no packages for "org.kde.plasma.activitypager"
no packages for "org.kde.kio_audiocd"
no packages for "org.kde.plasma.colorpicker"
no packages for "org.kde.plasma.pkupdates"
no packages for "org.kde.plasmashell"
no packages for "org.kde.plasma.fifteenpuzzle"
no packages for "org.kde.plasma.timer"
no packages for "org.kde.kscreen"
no packages for "org.kde.milou"
no packages for "org.kde.plasma.mediacontroller"
no packages for "org.kde.plasma.konsoleprofiles"
no packages for "org.kde.discover.packagekit"
no packages for "org.kde.breeze.desktop"
no packages for "org.kde.plasma.quickshare"
no packages for "org.kde.plasma.mediaframe"
no packages for "org.kde.plasma.systemmonitor.cpu"
no packages for "org.kde.plasma.katesessions"
no packages for "org.kde.plasma.activitybar"
no packages for "org.kde.potd"
no packages for "org.kde.slideshow"
no packages for "org.kde.plasma.icontasks"
no packages for "org.kde.okular-fb"
no packages for "org.kde.kinfocenter"
no packages for "org.kde.plasma.taskmanager"
no packages for "owncloud_kaccounts_ui"
no packages for "org.kde.okular-chm"
no packages for "org.kde.plasma.digitalclock"
no packages for "org.kde.plasma.desktop.appmenubar"
no packages for "org.kde.okular-txt"
no packages for "org.kde.plasma.volume"
no packages for "org.kde.plasma.desktop.defaultPanel"
no packages for "org.kde.plasma.kickerdash"
no packages for "org.kde.plasma.calculator"
no packages for "org.kde.plasma.appmenu"
no packages for "org.kde.plasma.notifications"
no packages for "org.kde.plasma.devicenotifier"
no packages for "org.kde.plasma.binaryclock"
no packages for "org.kde.plasma.desktop"
no packages for "org.kde.plasma.kimpanel"
no packages for "org.kde.okular-djvu"
no packages for "org.kde.wacomtablet"
no packages for "org.kde.plasma.kickoff"
no packages for "org.kde.plasma.minimizeall"
empty appstream db
qml: message: Por favor, asegúrese de que Appstream está bien configurado en su sistema.
took really long to fetch PackageKitBackend(0x55ef31db0f70)

(In reply to Vitor Louro Valadares from comment #16)
> An update, now discover is launching for some reason. I can't see any apps
> and now it complains about Appstream.
> 
> Here is the terminal output:
> 
> file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/
> MobileTextActionsToolBar.qml:62: TypeError: Cannot read property
> 'selectedText' of null
> file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/
> MobileTextActionsToolBar.qml:70: TypeError: Cannot read property
> 'selectedText' of null
> file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/
> MobileTextActionsToolBar.qml:78: TypeError: Cannot read property 'canPaste'
> of null
> invalid kns backend! "/usr/share/knsrcfiles/ksysguard.knsrc" because:
> "Config group not found! Check your KNS3 installation."
> adding empty sources model QStandardItemModel(0x55ef31dde230)
> Could not open the AppStream metadata pool "Some components have been
> ignored: Los archivos de metadatos tienen errores:
> /var/cache/app-info/xmls/download.opensuse.org-oss.xml.gz,
> /var/cache/app-info/xmls/download.opensuse.org-non-oss.xml.gz"
> no packages for "org.kde.okular-md"
> no packages for "org.kde.okular-ooo"
> no packages for "org.kde.plasma.quicklaunch"
> no packages for "org.kde.plasma.weather"
> no packages for "org.kde.plasma.systemmonitor.memory"
> no packages for "org.kde.desktopcontainment"
> no packages for "org.kde.plasma.networkmanagement"
> no packages for "org.kde.plasma.systemloadviewer"
> no packages for "org.kde.plasma.webbrowser"
> no packages for "org.kde.plasma.clipboard"
> no packages for "org.kde.okular-tiff"
> no packages for "org.kde.plasma.pager"
> no packages for "org.kde.okular-plucker"
> no packages for "org.kde.plasma.showActivityManager"
> no packages for "org.kde.plasma.notes"
> no packages for "org.kde.okular-dvi"
> no packages for "org.kde.okular-comicbook"
> no packages for "org.kde.plasma.trash"
> no packages for "org.kde.plasma.comic"
> no packages for "org.kde.plasma.windowlist"
> no packages for "org.kde.plasma.battery"
> no packages for "org.kde.hunyango"
> no packages for "org.kde.haenau"
> no packages for "org.kde.okular-poppler"
> no packages for "org.kde.plasma.lock_logout"
> no packages for "org.kde.plasma.keyboardindicator"
> no packages for "org.kde.paneltoolbox"
> no packages for "org.kde.plasma.printmanager"
> no packages for "org.kde.okular-xps"
> no packages for "org.kde.plasma.grouping"
> no packages for "org.kde.plasma.analogclock"
> no packages for "org.kde.plasma.folder"
> no packages for "org.kde.color"
> no packages for "org.kde.image"
> no packages for "org.kde.okular-epub"
> no packages for "org.kde.okular-fax"
> no packages for "org.kde.plasma.bluetooth"
> no packages for "org.kde.plasma.systemmonitor.diskusage"
> no packages for "org.kde.plasma.wacomtablet"
> no packages for "org.kde.plasma.showdesktop"
> no packages for "org.kde.okular-mobipocket"
> no packages for "org.kde.plasma.diskquota"
> no packages for "org.kde.plasma.systemtray"
> no packages for "org.kde.plasma.calendar"
> no packages for "org.gnome.cantarell"
> no packages for "org.kde.plasma.systemmonitor.diskactivity"
> no packages for "org.freedesktop.appstream.cli"
> no packages for "org.kde.breezedark.desktop"
> no packages for "org.kde.plasma.userswitcher"
> no packages for "org.kde.plasma.systemmonitor.net"
> no packages for "org.kde.plasma.desktop.emptyPanel"
> no packages for "org.kde.desktoptoolbox"
> no packages for "org.kde.okular-kimgio"
> no packages for "org.kde.plasma.fuzzyclock"
> no packages for "org.kde.plasma.kicker"
> no packages for "org.kde.plasma_applet_dict"
> no packages for "org.kde.plasma.activitypager"
> no packages for "org.kde.kio_audiocd"
> no packages for "org.kde.plasma.colorpicker"
> no packages for "org.kde.plasma.pkupdates"
> no packages for "org.kde.plasmashell"
> no packages for "org.kde.plasma.fifteenpuzzle"
> no packages for "org.kde.plasma.timer"
> no packages for "org.kde.kscreen"
> no packages for "org.kde.milou"
> no packages for "org.kde.plasma.mediacontroller"
> no packages for "org.kde.plasma.konsoleprofiles"
> no packages for "org.kde.discover.packagekit"
> no packages for "org.kde.breeze.desktop"
> no packages for "org.kde.plasma.quickshare"
> no packages for "org.kde.plasma.mediaframe"
> no packages for "org.kde.plasma.systemmonitor.cpu"
> no packages for "org.kde.plasma.katesessions"
> no packages for "org.kde.plasma.activitybar"
> no packages for "org.kde.potd"
> no packages for "org.kde.slideshow"
> no packages for "org.kde.plasma.icontasks"
> no packages for "org.kde.okular-fb"
> no packages for "org.kde.kinfocenter"
> no packages for "org.kde.plasma.taskmanager"
> no packages for "owncloud_kaccounts_ui"
> no packages for "org.kde.okular-chm"
> no packages for "org.kde.plasma.digitalclock"
> no packages for "org.kde.plasma.desktop.appmenubar"
> no packages for "org.kde.okular-txt"
> no packages for "org.kde.plasma.volume"
> no packages for "org.kde.plasma.desktop.defaultPanel"
> no packages for "org.kde.plasma.kickerdash"
> no packages for "org.kde.plasma.calculator"
> no packages for "org.kde.plasma.appmenu"
> no packages for "org.kde.plasma.notifications"
> no packages for "org.kde.plasma.devicenotifier"
> no packages for "org.kde.plasma.binaryclock"
> no packages for "org.kde.plasma.desktop"
> no packages for "org.kde.plasma.kimpanel"
> no packages for "org.kde.okular-djvu"
> no packages for "org.kde.wacomtablet"
> no packages for "org.kde.plasma.kickoff"
> no packages for "org.kde.plasma.minimizeall"
> empty appstream db
> qml: message: Por favor, asegúrese de que Appstream está bien configurado en
> su sistema.
> took really long to fetch PackageKitBackend(0x55ef31db0f70)

Same problem here on Discover 5.16.2-1.1 on openSUSE Tumbleweed 20190627. Discover now stays open on launch, but gives the message "Please make sure that Appstream is properly set up on your system". I get the same as  Vitor Louro Valadares above when launching plasma-discover from Konsole.

(In reply to Ms Hmm from comment #17)
> Same problem here on Discover 5.16.2-1.1 on openSUSE Tumbleweed 20190627.
> Discover now stays open on launch, but gives the message "Please make sure
> that Appstream is properly set up on your system". I get the same as  Vitor
> Louro Valadares above when launching plasma-discover from Konsole.

Agreed. You should maybe change the title, since it does not crash anymore.

(In reply to Frank Kruger from comment #18)
> (In reply to Ms Hmm from comment #17)
> > Same problem here on Discover 5.16.2-1.1 on openSUSE Tumbleweed 20190627.
> > Discover now stays open on launch, but gives the message "Please make sure
> > that Appstream is properly set up on your system". I get the same as  Vitor
> > Louro Valadares above when launching plasma-discover from Konsole.
> 
> Agreed. You should maybe change the title, since it does not crash anymore.

I've amended it slightly as it's now merely unusable rather than crashing...

Last I checked it still crash here relatively recently. When I get back on the machine again I'll double check and update this report accordingly.

It also crash here as per post #1 here, latest snapshot as of today.

(In reply to Frank Kruger from comment #11)
> FYI: With TW20190626 and after a reboot Discover is working again for me.

It seems that I was lucky for only two snapshots. After today's update to TW20190628 Discover crashes again with the known error messages (from the console): 

file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:70: TypeError: Cannot read property 'selectedText' of null
file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:78: TypeError: Cannot read property 'canPaste' of null
adding empty sources model QStandardItemModel(0x555e2c744190)
Segmentation fault (core dumped)

Created attachment 808939 [details]
plasma-discover gdb trace

I ran plasma-discover with gdb and got a backtrace. (once I installed libappstream4 debug symbols)
I only am sending the first 24 lines as if I let it show the whole backtrace, it goes on forever.(looping issue?)

(In reply to kevin whitaker from comment #23)
> Created attachment 808939 [details]
> plasma-discover gdb trace
Hm, I cannot make much sense of that either, unfortunately. (that crash certainly is not in plasma-discover though)

There was a backtrace added to the upstream bug report too (https://bugs.kde.org/show_bug.cgi?id=409195), that was in AppStream or rather lmdb (the latest update does use lmdb).

That really means that the trigger is the AppStream update as I suspected earlier.

People who need to use discover currently can reinstall the previous AppStream/libappstream version that I provide here meanwhile:
https://download.opensuse.org/repositories/home:/wolfi323:/boo1139463/openSUSE_Tumbleweed/

A downgrade of AppStream is of course not the proper action here IMHO.

I have no idea yet whether the bug is in AppStream or lmdb though...

Just for the record, I can reproduce the crash here now on Leap 15.1 with additional KDE repositories, after updating AppStream to 0.12.7, while it didn't crash before.

I didn't update it earlier because a vendor change was involved...

IOW, it works fine with the standard AppStream 0.12.6 (from the standard Leap 15.1 repos), but crashes with 0.12.7 (from KDE:Frameworks5, in my case).

(In reply to Wolfgang Bauer from comment #25)
> Just for the record, I can reproduce the crash here now on Leap 15.1 with
> additional KDE repositories, after updating AppStream to 0.12.7, while it
> didn't crash before.
> 
> I didn't update it earlier because a vendor change was involved...
> 
> IOW, it works fine with the standard AppStream 0.12.6 (from the standard
> Leap 15.1 repos), but crashes with 0.12.7 (from KDE:Frameworks5, in my case).

I'm not too familiar with the appstream package. Will downgrading it possibly break anything else or cause any other issues? And is that the best course of action for someone on leap 15.1 to take for now until the issue is fixed?

(In reply to Rylee K from comment #26)
> I'm not too familiar with the appstream package. Will downgrading it
> possibly break anything else or cause any other issues?
I'd say the chances are quite low that a downgrade would break anything.

I was actually using the previous version until now, because I didn't notice that it hadn't been updated... ;-)

> And is that the best
> course of action for someone on leap 15.1 to take for now until the issue is
> fixed?
Probably, if you do want to use discover at least.
(I actually don't use it personally, I have to admit, so it wouldn't matter much for me)

For Tumbleweed users, see comment#24.

PS: the critical part seems to be libappstream4, downgrading that makes discover start here (though I haven't tested the actual functionality).

It's certainly a good idea to downgrade AppStream itself and libAppStreamQt2 too though.

(In reply to kevin whitaker from comment #23)
> Created attachment 808939 [details]
> plasma-discover gdb trace
> 
> I ran plasma-discover with gdb and got a backtrace. (once I installed
> libappstream4 debug symbols)
> I only am sending the first 24 lines as if I let it show the whole
> backtrace, it goes on forever.(looping issue?)
Indeed.

I did some investigation yesterday (had the same backtrace here).
According to some debug output I added, AppStream apparently tried to add the same line over and over again in an endless loop, and eventually ran out of memory (resulting in the crash) I suppose.

Also, setting LANG=C did avoid the crash.

It doesn't crash anymore today here though for some reason... :-/ (I didn't install any updates)

I can confirm LANG=C causes the interface to stay up and not crash. That being said, it now says appstream isn't set up correctly and is still unusable for installations. Also intretesting to note, after passing that var once, passing it again causes crashes like before, but leaving it out acts like the first time I passed LANG=C.

Well, I deleted /var/cache/app-info/ here and ran "zypper appstream-cache refresh", and the crashes were back. So I should be able to investigate more (probably not today anymore though).

Interestingly, I ran "zypper appstream-cache refresh" again afterwards, and the crash was gone again. And when I ran that again, discover crashed again afterwards, and deleting /var/cache/app-info/ "fixed" it again.

So it seems something is flaky when actually creating the cache... Maybe the actual problem is in libzypp-plugin-appdata? (might be an incompatibility with the newer AppStream perhaps)

JFYI: The situation does not change with KDE Plasma 5.16.3 and KDE Frameworks 5.60.0, with AppStream still at version 0.12.7.

hello !

if it helps:

Système d'exploitation : openSUSE Tumbleweed 20190724
Version de KDE Plasma : 5.16.2
Version de KDE Frameworks : 5.59.0
Version de Qt : 5.13.0
Version de noyau : 5.2.1-1-default
Type de système d'exploitation : 64-bit
Processeurs : 4 × AMD Phenom(tm) II X4 965 Processor
Mémoire : 15,7 Gio de mémoire vive

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christian@localhost:~> plasma-discover
file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:62: TypeError: Cannot read property 'selectedText' of null
file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:70: TypeError: Cannot read property 'selectedText' of null
file:///usr/lib64/qt5/qml/QtQuick/Controls.2/org.kde.desktop/private/MobileTextActionsToolBar.qml:78: TypeError: Cannot read property 'canPaste' of null
invalid kns backend! "/usr/share/knsrcfiles/ksysguard.knsrc" because: "Config group not found! Check your KNS3 installation."
adding empty sources model QStandardItemModel(0x563083735880)
Erreur de segmentation (core dumped)

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christian@localhost:~> sudo plasma-discover
[sudo] Mot de passe de root : 
qt.qpa.xcb: could not connect to display 
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
error: XDG_RUNTIME_DIR not set in the environment.
Failed to create wl_display (No such file or directory)
qt.qpa.plugin: Could not load the Qt platform plugin "wayland" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: wayland-org.kde.kwin.qpa, eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.

Abandon

I just found this upstream commit (in AppStream) that's supposed to fix an infinite loop (which seems to match the crash backtrace AFAICS):
https://github.com/ximion/appstream/commit/8a7acbf81de51ff991bf8211eff248b46c2b5421

Can somebody please test the new packages from here if they fix the crash?
https://download.opensuse.org/repositories/home:/wolfi323:/boo1139463_crashfix/openSUSE_Tumbleweed/
Thanks.

I probably won't be able to try myself until next week...

PS, @christian mathieu (comment#34):
You should not (and cannot) run discover with sudo.

The first and foremost problem here is that sudo doesn't pass the necessary environment for security reasons, so the app doesn't even find the display.
That's not a bug, and no indication for a problem either.

(In reply to Wolfgang Bauer from comment #34)
> I just found this upstream commit (in AppStream) that's supposed to fix an
> infinite loop (which seems to match the crash backtrace AFAICS):
> https://github.com/ximion/appstream/commit/
> 8a7acbf81de51ff991bf8211eff248b46c2b5421
> 
> Can somebody please test the new packages from here if they fix the crash?
> https://download.opensuse.org/repositories/home:/wolfi323:/
> boo1139463_crashfix/openSUSE_Tumbleweed/
> Thanks.

Tested.

When installing:
Zypper shows this warning: ‘The AppStream system cache was updated, but some errors were detected, which might lead to missing metadata. Refer to the verbose log for more information.’

When running plasma-discover:
Crashes at launch.

After sudo rm -rf /var/cache/app-info/:
Discover does *not* crash at launch. But it shows the message ‘Please check your connectivity’, the ‘Fetching updates…’ never ends, and all software categories are empty.

No news? On my Tumbleweed Discover it is still broken. But I managed to start it and I can use FlatHub, but I can't install applications from the openSUSE repositories.

Appears to be caused by AppStream 0.12.7, I filed an issue and also left a comment in the KDE bugtracker: https://github.com/ximion/appstream/issues/243

git master does not work either so it's not fixed yet.

Root cause is an invalid metainfo file from QXmlEditor.

A fixed AppStream which doesn't crash is on its way to TW.

(In reply to Fabian Vogt from comment #39)
> Root cause is an invalid metainfo file from QXmlEditor.
> 
> A fixed AppStream which doesn't crash is on its way to TW.

Thanks, great news.

(In reply to Fabian Vogt from comment #39)
> Root cause is an invalid metainfo file from QXmlEditor.
> 
> A fixed AppStream which doesn't crash is on its way to TW.

After updating Discover and Apptream from https://download.opensuse.org/repositories/KDE:/Frameworks5/openSUSE_Factory/ the above-mentioned issue is solved for me. Even the bug "Check Connectivity" instead of displaying content (https://bugs.kde.org/show_bug.cgi?id=409220) is gone. Thanks a lot!