Bug 400447

Summary:	cantor.knsrc causes plasma-discover to hang when opening
Product:	[Applications] Discover	Reporter:	Claudius <claudius+kde>
Component:	KNewStuff Backend	Assignee:	Aleix Pol <aleixpol>
Status:	RESOLVED FIXED
Severity:	normal	CC:	aleixpol, alexander.semke, alexanderrieder, leinir, warquark
Priority:	NOR
Version First Reported In:	5.14.2
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Claudius 2018-10-29 14:44:46 UTC

plasma-discover uses 100% cpu and seems to hang/freeze for several minutes when cantor*.knsrc files reside in /etc/xdg

STEPS TO REPRODUCE
1. install cantor
2. open discover


OBSERVED RESULT

the discover UI freezes for several minutes and these messages appear on stdout while plasma-discover memory consumption rises to about 800MB:

org.kde.knewstuff.core: Could not find category "Cantor (Python 3)"
org.kde.knewstuff.core: Could not find category "Cantor (KAlgebra)"
org.kde.knewstuff.core: Could not find category "Cantor (Python 2)"
org.kde.knewstuff.core: Could not find category "Cantor (Scilab)"
org.kde.knewstuff.core: Could not find category "Cantor (Octave)"
org.kde.knewstuff.core: Could not find category "Cantor (Sage)"
org.kde.knewstuff.core: Could not find category "Cantor (Maxima)"
org.kde.knewstuff.core: Could not find category "Cantor (R)"
org.kde.knewstuff.core: Could not find category "Cantor (Lua)"
org.kde.knewstuff.core: Could not find category "Cantor (Qalculate)"
invalid kns backend! "/etc/xdg/cantor_scilab.knsrc" because: "All categories are missing"
org.kde.plasma.libdiscover: Discarding invalid backend "cantor_scilab.knsrc"
kns error "/etc/xdg/cantor_scilab.knsrc" "Invalid Cantor_scilab backend, contact your distributor."
org.kde.knewstuff.core: Could not find category "Cantor (Python 3)"
org.kde.knewstuff.core: Could not find category "Cantor (KAlgebra)"
org.kde.knewstuff.core: Could not find category "Cantor (Python 2)"
org.kde.knewstuff.core: Could not find category "Cantor (Scilab)"
org.kde.knewstuff.core: Could not find category "Cantor (Octave)"
org.kde.knewstuff.core: Could not find category "Cantor (Sage)"
org.kde.knewstuff.core: Could not find category "Cantor (Maxima)"
org.kde.knewstuff.core: Could not find category "Cantor (R)"
org.kde.knewstuff.core: Could not find category "Cantor (Lua)"
org.kde.knewstuff.core: Could not find category "Cantor (Qalculate)"
invalid kns backend! "/etc/xdg/cantor_qalculate.knsrc" because: "All categories are missing"
org.kde.plasma.libdiscover: Discarding invalid backend "cantor_qalculate.knsrc"
kns error "/etc/xdg/cantor_qalculate.knsrc" "Invalid Cantor_qalculate backend, contact your distributor."
org.kde.knewstuff.core: Could not find category "Cantor (Python 3)"
org.kde.knewstuff.core: Could not find category "Cantor (KAlgebra)"
org.kde.knewstuff.core: Could not find category "Cantor (Python 2)"
org.kde.knewstuff.core: Could not find category "Cantor (Scilab)"
org.kde.knewstuff.core: Could not find category "Cantor (Octave)"
org.kde.knewstuff.core: Could not find category "Cantor (Sage)"
org.kde.knewstuff.core: Could not find category "Cantor (Maxima)"
org.kde.knewstuff.core: Could not find category "Cantor (R)"
org.kde.knewstuff.core: Could not find category "Cantor (Lua)"
org.kde.knewstuff.core: Could not find category "Cantor (Qalculate)"
invalid kns backend! "/etc/xdg/cantor_sage.knsrc" because: "All categories are missing"
org.kde.plasma.libdiscover: Discarding invalid backend "cantor_sage.knsrc"
kns error "/etc/xdg/cantor_sage.knsrc" "Invalid Cantor_sage backend, contact your distributor."
org.kde.knewstuff.core: Could not find category "Cantor (Python 3)"
org.kde.knewstuff.core: Could not find category "Cantor (KAlgebra)"
org.kde.knewstuff.core: Could not find category "Cantor (Python 2)"
org.kde.knewstuff.core: Could not find category "Cantor (Scilab)"
org.kde.knewstuff.core: Could not find category "Cantor (Octave)"
org.kde.knewstuff.core: Could not find category "Cantor (Sage)"
org.kde.knewstuff.core: Could not find category "Cantor (Maxima)"
org.kde.knewstuff.core: Could not find category "Cantor (R)"
org.kde.knewstuff.core: Could not find category "Cantor (Lua)"
org.kde.knewstuff.core: Could not find category "Cantor (Qalculate)"
invalid kns backend! "/etc/xdg/cantor_kalgebra.knsrc" because: "All categories are missing"
org.kde.plasma.libdiscover: Discarding invalid backend "cantor_kalgebra.knsrc"
kns error "/etc/xdg/cantor_kalgebra.knsrc" "Invalid Cantor_kalgebra backend, contact your distributor."
org.kde.knewstuff.core: Could not find category "Cantor (Python 3)"
org.kde.knewstuff.core: Could not find category "Cantor (KAlgebra)"
org.kde.knewstuff.core: Could not find category "Cantor (Python 2)"
org.kde.knewstuff.core: Could not find category "Cantor (Scilab)"
org.kde.knewstuff.core: Could not find category "Cantor (Octave)"
org.kde.knewstuff.core: Could not find category "Cantor (Sage)"
org.kde.knewstuff.core: Could not find category "Cantor (Maxima)"
org.kde.knewstuff.core: Could not find category "Cantor (R)"
org.kde.knewstuff.core: Could not find category "Cantor (Lua)"
org.kde.knewstuff.core: Could not find category "Cantor (Qalculate)"
invalid kns backend! "/etc/xdg/cantor.knsrc" because: "All categories are missing"
org.kde.plasma.libdiscover: Discarding invalid backend "cantor.knsrc"
kns error "/etc/xdg/cantor.knsrc" "Invalid Cantor backend, contact your distributor."
org.kde.knewstuff.core: Could not find category "Cantor (Python 3)"
org.kde.knewstuff.core: Could not find category "Cantor (KAlgebra)"
org.kde.knewstuff.core: Could not find category "Cantor (Python 2)"
org.kde.knewstuff.core: Could not find category "Cantor (Scilab)"
org.kde.knewstuff.core: Could not find category "Cantor (Octave)"
org.kde.knewstuff.core: Could not find category "Cantor (Sage)"
org.kde.knewstuff.core: Could not find category "Cantor (Maxima)"
org.kde.knewstuff.core: Could not find category "Cantor (R)"
org.kde.knewstuff.core: Could not find category "Cantor (Lua)"
org.kde.knewstuff.core: Could not find category "Cantor (Qalculate)"
invalid kns backend! "/etc/xdg/cantor_maxima.knsrc" because: "All categories are missing"
org.kde.plasma.libdiscover: Discarding invalid backend "cantor_maxima.knsrc"
kns error "/etc/xdg/cantor_maxima.knsrc" "Invalid Cantor_maxima backend, contact your distributor."
org.kde.knewstuff.core: Could not find category "Cantor (Python 3)"
org.kde.knewstuff.core: Could not find category "Cantor (KAlgebra)"
org.kde.knewstuff.core: Could not find category "Cantor (Python 2)"
org.kde.knewstuff.core: Could not find category "Cantor (Scilab)"
org.kde.knewstuff.core: Could not find category "Cantor (Octave)"
org.kde.knewstuff.core: Could not find category "Cantor (Sage)"
org.kde.knewstuff.core: Could not find category "Cantor (Maxima)"
org.kde.knewstuff.core: Could not find category "Cantor (R)"
org.kde.knewstuff.core: Could not find category "Cantor (Lua)"
org.kde.knewstuff.core: Could not find category "Cantor (Qalculate)"
invalid kns backend! "/etc/xdg/cantor_lua.knsrc" because: "All categories are missing"
org.kde.plasma.libdiscover: Discarding invalid backend "cantor_lua.knsrc"
kns error "/etc/xdg/cantor_lua.knsrc" "Invalid Cantor_lua backend, contact your distributor."
org.kde.knewstuff.core: Could not find category "Cantor (Python 3)"
org.kde.knewstuff.core: Could not find category "Cantor (KAlgebra)"
org.kde.knewstuff.core: Could not find category "Cantor (Python 2)"
org.kde.knewstuff.core: Could not find category "Cantor (Scilab)"
org.kde.knewstuff.core: Could not find category "Cantor (Octave)"
org.kde.knewstuff.core: Could not find category "Cantor (Sage)"
org.kde.knewstuff.core: Could not find category "Cantor (Maxima)"
org.kde.knewstuff.core: Could not find category "Cantor (R)"
org.kde.knewstuff.core: Could not find category "Cantor (Lua)"
org.kde.knewstuff.core: Could not find category "Cantor (Qalculate)"
invalid kns backend! "/etc/xdg/cantor_python3.knsrc" because: "All categories are missing"
org.kde.plasma.libdiscover: Discarding invalid backend "cantor_python3.knsrc"
kns error "/etc/xdg/cantor_python3.knsrc" "Invalid Cantor_python3 backend, contact your distributor."
org.kde.knewstuff.core: Could not find category "Cantor (Python 3)"
org.kde.knewstuff.core: Could not find category "Cantor (KAlgebra)"
org.kde.knewstuff.core: Could not find category "Cantor (Python 2)"
org.kde.knewstuff.core: Could not find category "Cantor (Scilab)"
org.kde.knewstuff.core: Could not find category "Cantor (Octave)"
org.kde.knewstuff.core: Could not find category "Cantor (Sage)"
org.kde.knewstuff.core: Could not find category "Cantor (Maxima)"
org.kde.knewstuff.core: Could not find category "Cantor (R)"
org.kde.knewstuff.core: Could not find category "Cantor (Lua)"
org.kde.knewstuff.core: Could not find category "Cantor (Qalculate)"
invalid kns backend! "/etc/xdg/cantor_python2.knsrc" because: "All categories are missing"
org.kde.plasma.libdiscover: Discarding invalid backend "cantor_python2.knsrc"
kns error "/etc/xdg/cantor_python2.knsrc" "Invalid Cantor_python2 backend, contact your distributor."
org.kde.knewstuff.core: Could not find category "Cantor (Python 3)"
org.kde.knewstuff.core: Could not find category "Cantor (KAlgebra)"
org.kde.knewstuff.core: Could not find category "Cantor (Python 2)"
org.kde.knewstuff.core: Could not find category "Cantor (Scilab)"
org.kde.knewstuff.core: Could not find category "Cantor (Octave)"
org.kde.knewstuff.core: Could not find category "Cantor (Sage)"
org.kde.knewstuff.core: Could not find category "Cantor (Maxima)"
org.kde.knewstuff.core: Could not find category "Cantor (R)"
org.kde.knewstuff.core: Could not find category "Cantor (Lua)"
org.kde.knewstuff.core: Could not find category "Cantor (Qalculate)"
invalid kns backend! "/etc/xdg/cantor_octave.knsrc" because: "All categories are missing"
org.kde.plasma.libdiscover: Discarding invalid backend "cantor_octave.knsrc"
kns error "/etc/xdg/cantor_octave.knsrc" "Invalid Cantor_octave backend, contact your distributor."
org.kde.knewstuff.core: Could not find category "Cantor (Python 3)"
org.kde.knewstuff.core: Could not find category "Cantor (KAlgebra)"
org.kde.knewstuff.core: Could not find category "Cantor (Python 2)"
org.kde.knewstuff.core: Could not find category "Cantor (Scilab)"
org.kde.knewstuff.core: Could not find category "Cantor (Octave)"
org.kde.knewstuff.core: Could not find category "Cantor (Sage)"
org.kde.knewstuff.core: Could not find category "Cantor (Maxima)"
org.kde.knewstuff.core: Could not find category "Cantor (R)"
org.kde.knewstuff.core: Could not find category "Cantor (Lua)"
org.kde.knewstuff.core: Could not find category "Cantor (Qalculate)"
invalid kns backend! "/etc/xdg/cantor_r.knsrc" because: "All categories are missing"
org.kde.plasma.libdiscover: Discarding invalid backend "cantor_r.knsrc"
kns error "/etc/xdg/cantor_r.knsrc" "Invalid Cantor_r backend, contact your distributor."
org.kde.knewstuff.core: Could not find category "Parley"
org.kde.knewstuff.core: "Socket operation timed out"
kns error "/etc/xdg/kalzium.knsrc" "Loading of providers from file: http://data.kstuff.org/cgi-bin/hotstuff-provider?site=kalzium failed"
qml: message: kalzium.knsrc: Loading of providers from file: http://data.kstuff.org/cgi-bin/hotstuff-provider?site=kalzium failed
PackageKit stopped running!

EXPECTED RESULT

Normal startup of discover. Memory consumption is maybe a bug in appstream/discover.

SOFTWARE VERSIONS
(available in About System)
KDE Plasma Version: 5.14.2
KDE Frameworks Version: 5.51.0
Qt Version: 5.11.2

Using Arch packages:
cantor 18.08.2-1
appstream-0.12.3-1
discover-5.14.2-1


ADDITIONAL INFORMATION

When cantor is not installed opening discover works fine.

Comment 1 Nikita Sirgienko 2018-11-03 19:17:21 UTC

I can't reproduce it.
On my Ubuntu 18.04 and Kde Neon Useredition-20180920 (in VirtualBox) the presence or absence of Cantor does not affect on Discover.
That about this messages about categories: in this moment we haven't any categories in kde.store.
Cantor without any backends also reproduce this error?

Comment 2 Aleix Pol 2018-11-07 02:44:05 UTC

I've just been testing this and it works fine for me.

Can you reproduce the issue?

The CPU/Memory consumption problem you're referring to has been solved already for 5.15. Sorry for the inconvenience.

Comment 3 Aleix Pol 2018-11-07 14:55:39 UTC

Cantor developers tell me that these categories were just added, now it will work fine.
Sorry for the inconvenience.

Comment 4 Claudius 2018-11-07 19:32:11 UTC

Sorry that I have been unresponsive, I was away until now.
I will get to my Arch machine tomorrow to check it out. Thanks for the quick fix!

Comment 5 Claudius 2018-11-08 14:18:04 UTC

Now with
cantor 18.08.3-1
appstream 0.12.3-1
discover 5.14.3-1

on KDE 5.14.3

all problems have gone away!

Thanks again.