Hello, this might be caused by having the current plasma-desktop package built against libkf5plasma-dev (5.49.0-1) [1], while in buster/testing is only version (5.47.0-1).
Looks like that package is not yet migrated from unstable to testing. The tracker page [2] tells some reasons for not yet being migrated. [1] https://buildd.debian.org/status/fetch.php?pkg=plasma-desktop&arch=amd64&ver=4%3A5.13.4-1&stamp=1534764652&raw=0 [2] https://tracker.debian.org/pkg/plasma-framework Kind regards, Bernhard
apt source plasma-workspace apt source libkf5plasma5 apt source libkf5package5 export PKG="plasma-workspace-dbgsym libkf5plasma5-dbgsym libkf5package5-dbgsym libkf5coreaddons5-dbgsym"; apt install $PKG; apt-mark auto $PKG $ grep -n "Unable to load applet" . -R ./plasma-windowed/plasmawindowedcorona.cpp:72: qWarning() << "Unable to load applet" << applet << "with arguments" <<arguments; ./plasma-windowed/plasmawindowedcorona.cpp:91: qWarning() << "Unable to load applet" << applet << "with arguments" <<arguments; # ~/.gdb/qt5-gdbinit: https://github.com/Lekensteyn/qt5printers.git gdb -q --args plasmawindowed org.kde.plasma.systemtray set height 0 set width 0 set pagination off directory /home/bernhard/data/entwicklung/2018/debian/10_buster/907301_plasma-no-systray/plasma-workspace/orig/plasma-workspace-5.13.4 directory /home/bernhard/data/entwicklung/2018/debian/10_buster/907301_plasma-no-systray/libkf5plasma5/orig/plasma-framework-5.47.0 directory /home/bernhard/data/entwicklung/2018/debian/10_buster/907301_plasma-no-systray/libkf5package5/orig/kpackage-5.47.0 directory /home/bernhard/data/entwicklung/2018/debian/10_buster/907301_plasma-no-systray/libkf5coreaddons5/orig/kcoreaddons-5.47.0 source ~/.gdb/qt5-gdbinit b plasmawindowedcorona.cpp:89 b Plasma::PluginLoader::loadApplet b KPackage::PackageLoader::loadPackage b packageloader.cpp:133 b pluginloader.cpp:201 (gdb) next 871 if (version < minVersion || version > maxVersion) { (gdb) print minVersion $10 = 327680 (gdb) print version $9 = 340224 (gdb) print maxVersion $11 = 339772 (gdb) bt #0 Plasma::PluginLoader::isPluginVersionCompatible (this=this@entry=0x5555556a1030, loader=...) at ./src/plasma/pluginloader.cpp:871 #1 0x00007ffff7a97606 in Plasma::PluginLoader::loadApplet (this=0x5555556a1030, name="org.kde.plasma.systemtray", appletId=3, args=<empty>) at ./src/plasma/pluginloader.cpp:202 #2 0x000055555555bbd9 in PlasmaWindowedCorona::loadApplet (this=<optimized out>, applet="org.kde.plasma.systemtray", arguments=<empty>) at ./plasma-windowed/plasmawindowedcorona.cpp:89 #3 0x000055555555ae2b in main (argc=<optimized out>, argv=<optimized out>) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qlist.h:115 (gdb) list Plasma::PluginLoader::isPluginVersionCompatible 857 858 bool PluginLoader::isPluginVersionCompatible(KPluginLoader &loader) 859 { 860 const quint32 version = loader.pluginVersion(); 861 if (version == quint32(-1)) { 862 // unversioned, just let it through 863 qCWarning(LOG_PLASMA) << loader.fileName() << "unversioned plugin detected, may result in instability"; 864 return true; 865 } 866 867 // we require PLASMA_VERSION_MAJOR and PLASMA_VERSION_MINOR 868 const quint32 minVersion = PLASMA_MAKE_VERSION(PLASMA_VERSION_MAJOR, 0, 0); 869 const quint32 maxVersion = PLASMA_MAKE_VERSION(PLASMA_VERSION_MAJOR, PLASMA_VERSION_MINOR, 60); 870 871 if (version < minVersion || version > maxVersion) { 872 #ifndef NDEBUG 873 qCDebug(LOG_PLASMA) << loader.fileName() << ": this plugin is compiled against incompatible Plasma version" << version 874 << "This build is compatible with" << PLASMA_VERSION_MAJOR << ".0.0 (" << minVersion 875 << ") to" << PLASMA_VERSION_STRING << "(" << maxVersion << ")"; 876 #endif 877 return false; 878 } 879 880 return true; 881 } (gdb) bt #0 KPluginLoader::load (this=this@entry=0x7fffffffdda0) at ./src/lib/plugin/kpluginloader.cpp:198 #1 0x00007ffff5ce701a in KPluginLoader::pluginVersion (this=this@entry=0x7fffffffdda0) at ./src/lib/plugin/kpluginloader.cpp:132 #2 0x00007ffff7a92295 in Plasma::PluginLoader::isPluginVersionCompatible (this=this@entry=0x55555568dc60, loader=...) at ./src/plasma/pluginloader.cpp:860 #3 0x00007ffff7a97606 in Plasma::PluginLoader::loadApplet (this=0x55555568dc60, name="org.kde.plasma.systemtray", appletId=3, args=<empty>) at ./src/plasma/pluginloader.cpp:202 #4 0x000055555555bbd9 in PlasmaWindowedCorona::loadApplet (this=<optimized out>, applet="org.kde.plasma.systemtray", arguments=<empty>) at ./plasma-windowed/plasmawindowedcorona.cpp:89 #5 0x000055555555ae2b in main (argc=<optimized out>, argv=<optimized out>) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qlist.h:115 (gdb) list KPluginLoader::load 179 180 bool KPluginLoader::load() 181 { 182 Q_D(KPluginLoader); 183 184 if (!d->loader->load()) { 185 return false; 186 } 187 188 if (d->pluginVersionResolved) { 189 return true; 190 } 191 192 Q_ASSERT(!fileName().isEmpty()); 193 QLibrary lib(fileName()); 194 Q_ASSERT(lib.isLoaded()); // already loaded by QPluginLoader::load() 195 196 // TODO: this messes up KPluginLoader::errorString(): it will change from unknown error to could not resolve kde_plugin_version 197 quint32 *version = reinterpret_cast<quint32 *>(lib.resolve("kde_plugin_version")); 198 if (version) { 199 d->pluginVersion = *version; 200 } else { 201 d->pluginVersion = ~0U; 202 } 203 d->pluginVersionResolved = true; 204 205 return true; 206 } (gdb) print *version $24 = 340224 $ objdump -TC /usr/lib/x86_64-linux-gnu/qt5/plugins/plasma/applets/org.kde.plasma.systemtray.so | grep kde_plugin_version 0000000000005140 g DO .rodata 0000000000000004 Base kde_plugin_version gdb -batch -ex 'file /usr/lib/x86_64-linux-gnu/qt5/plugins/plasma/applets/org.kde.plasma.systemtray.so' -ex 'print kde_plugin_version' $1 = 340224 $ QT_LOGGING_RULES="*plasma*=true" plasmawindowed org.kde.plasma.systemtray org.kde.plasmaquick: Applet preload policy set to 1 org.kde.plasma: "/usr/lib/x86_64-linux-gnu/qt5/plugins/plasma_containmentactions_paste.so" : this plugin is compiled against incompatible Plasma version 340224 This build is compatible with 5 .0.0 ( 327680 ) to 5.47.0 ( 339772 ) org.kde.plasma: "/usr/lib/x86_64-linux-gnu/qt5/plugins/plasma_containmentactions_contextmenu.so" : this plugin is compiled against incompatible Plasma version 340224 This build is compatible with 5 .0.0 ( 327680 ) to 5.47.0 ( 339772 ) org.kde.plasma: "/usr/lib/x86_64-linux-gnu/qt5/plugins/plasma_containmentactions_switchdesktop.so" : this plugin is compiled against incompatible Plasma version 340224 This build is compatible with 5 .0.0 ( 327680 ) to 5.47.0 ( 339772 ) org.kde.plasma: "/usr/lib/x86_64-linux-gnu/qt5/plugins/plasma/applets/org.kde.plasma.systemtray.so" : this plugin is compiled against incompatible Plasma version 340224 This build is compatible with 5 .0.0 ( 327680 ) to 5.47.0 ( 339772 ) Unable to load applet "org.kde.plasma.systemtray" with arguments () # export PKG="baloo-kf5-dev extra-cmake-modules gir1.2-harfbuzz-0.0 gir1.2-nm-1.0 kdesignerplugin-data kdoctools5 kgendesignerplugin kgendesignerplugin-bin kinit-dev kross-dev kscreenlocker-dev kwin-dev libappstreamqt-dev libboost-dev libboost1.62-dev libcln-dev libdbusmenu-qt5-dev libegl1-mesa-dev libepoxy-dev libglib2.0-dev libgmp-dev libgmpxx4ldbl libgps-dev libgraphite2-dev libharfbuzz-dev libharfbuzz-gobject0 libice-dev libicu-dev libicu-le-hb-dev libkf5activities-dev libkf5archive-dev libkf5attica-dev libkf5auth-dev libkf5auth-dev-bin libkf5bookmarks-dev libkf5codecs-dev libkf5completion-dev libkf5config-dev libkf5config-dev-bin libkf5configwidgets-dev libkf5coreaddons-dev libkf5coreaddons-dev-bin libkf5crash-dev libkf5dbusaddons-dev libkf5declarative-dev libkf5dnssd-dev libkf5doctools-dev libkf5emoticons-dev libkf5filemetadata-dev libkf5globalaccel-dev libkf5guiaddons-dev libkf5holidays-dev libkf5i18n-dev libkf5iconthemes-dev libkf5idletime-dev libkf5itemmodels-dev libkf5itemviews-dev libkf5jobwidgets-dev libkf5jsembed-dev libkf5kcmutils-dev libkf5kdelibs4support-dev libkf5khtml-dev libkf5kio-dev libkf5kjs-dev libkf5mediaplayer-data libkf5mediaplayer-dev libkf5mediaplayer5 libkf5networkmanagerqt-dev libkf5newstuff-dev libkf5notifications-dev libkf5notifyconfig-dev libkf5package-dev libkf5parts-dev libkf5plasma-dev libkf5plotting-dev libkf5plotting5 libkf5prison-dev libkf5pty-dev libkf5runner-dev libkf5screen-dev libkf5service-dev libkf5solid-dev libkf5sonnet-dev libkf5sonnet-dev-bin libkf5style-dev libkf5su-dev libkf5sysguard-dev libkf5texteditor-dev libkf5textwidgets-dev libkf5threadweaver-dev libkf5unitconversion-dev libkf5wallet-dev libkf5wayland-dev libkf5webkit-dev libkf5webkit5 libkf5widgetsaddons-dev libkf5windowsystem-dev libkf5xmlgui-dev libkf5xmlrpcclient-dev liblsofui7 libnm-dev libpam0g-dev libpcre16-3 libpcre3-dev libpcre32-3 libphonon4qt5-dev libphonon4qt5experimental-dev libphonon4qt5experimental4 libqalculate-dev libqt5quickparticles5 libqt5quicktest5 libqt5sensors5-dev libqt5webkit5-dev libqt5x11extras5-dev libraw1394-dev libsm-dev libudev-dev libwayland-dev libxapian-dev libxcb-composite0-dev libxcb-damage0-dev libxcb-image0-dev libxcb-keysyms1-dev libxcb-shm0-dev libxcb-util0-dev libxcursor-dev libxi-dev libxkbcommon-dev libxkbfile-dev libxml2-dev libxrandr-dev libxrender-dev libxtst-dev qtdeclarative5-dev qtdeclarative5-dev-tools qtscript5-dev qttools5-dev x11proto-record-dev"; apt install $PKG; apt-mark auto $PKG apt build-dep plasma-workspace plasma-workspace-5.13.4 dpkg-buildpackage -b gdb -batch -ex 'file ./obj-x86_64-linux-gnu/bin/org.kde.plasma.systemtray.so' -ex 'print kde_plugin_version' $1 = 339712 cd .. dpkg -l | grep -E "$(ls -1 *.deb | cut -d_ -f 1 | xargs echo | tr ' ' '|')" dpkg -i libcolorcorrect5_5.13.4-1_amd64.deb libkworkspace5-5_5.13.4-1_amd64.deb libplasma-geolocation-interface5_5.13.4-1_amd64.deb libtaskmanager6_5.13.4-1_amd64.deb libweather-ion7_5.13.4-1_amd64.deb plasma-workspace_5.13.4-1_amd64.deb plasma-workspace-dbgsym_5.13.4-1_amd64.deb plasma-workspace-wayland_5.13.4-1_amd64.deb sddm-theme-breeze_5.13.4-1_amd64.deb dpkg -l | grep -E "$(ls -1 *.deb | cut -d_ -f 1 | xargs echo | tr ' ' '|')" | cut -d" " -f 3 | xargs echo apt-mark auto libcolorcorrect5 libkworkspace5-5 libplasma-geolocation-interface5 libtaskmanager6 libweather-ion7 plasma-workspace plasma-workspace-dbgsym plasma-workspace-wallpapers plasma-workspace-wayland sddm-theme-breeze Related places in include files in testing package: /usr/include/KF5/plasma_version.h:#define PLASMA_VERSION_STRING "5.47.0" /usr/include/KF5/plasma/applet.h: K_EXPORT_PLUGIN_VERSION(PLASMA_VERSION)
