Qt - Module "QtQuick.Controls" is not installed - qt

Question

I try to deploy a QT application which works fine on a PC. The application is deployed in an image of a yocto installation, based on ASEM, with release "morty".
I receive the error message "qml: ERROR loading component: qrc:/GUI/InputDialog.qml:3 module "QtQuick.Controls" version 2.0 is not installed"
However, I don't see any trouble in the LDD output:
ldd $clientApp
linux-vdso.so.1 (0x7ed4b000)
libquazip.so.1 => /usr/lib/libquazip.so.1 (0x76f72000)
libQt5QuickWidgets.so.5 => /usr/lib/libQt5QuickWidgets.so.5 (0x76f64000)
libQt5Quick.so.5 => /usr/lib/libQt5Quick.so.5 (0x76c5e000)
libQt5Widgets.so.5 => /usr/lib/libQt5Widgets.so.5 (0x7674c000)
libQt5Gui.so.5 => /usr/lib/libQt5Gui.so.5 (0x762dd000)
libQt5Qml.so.5 => /usr/lib/libQt5Qml.so.5 (0x75f8d000)
libQt5Network.so.5 => /usr/lib/libQt5Network.so.5 (0x75e3d000)
libQt5Xml.so.5 => /usr/lib/libQt5Xml.so.5 (0x75e0d000)
libQt5Sql.so.5 => /usr/lib/libQt5Sql.so.5 (0x75dc1000)
libQt5Test.so.5 => /usr/lib/libQt5Test.so.5 (0x75d8c000)
libQt5Core.so.5 => /usr/lib/libQt5Core.so.5 (0x75861000)
libpthread.so.0 => /lib/libpthread.so.0 (0x75839000)
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x756f3000)
libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x756c7000)
libc.so.6 => /lib/libc.so.6 (0x7558b000)
libGLESv2.so.2 => /usr/lib/libGLESv2.so.2 (0x75492000)
libm.so.6 => /lib/libm.so.6 (0x75414000)
libz.so.1 => /lib/libz.so.1 (0x753f2000)
libpng16.so.16 => /usr/lib/libpng16.so.16 (0x753ba000)
libmysqlclient.so.18 => /usr/lib/libmysqlclient.so.18 (0x750e9000)
libdl.so.2 => /lib/libdl.so.2 (0x750d6000)
libglib-2.0.so.0 => /usr/lib/libglib-2.0.so.0 (0x74fd7000)
librt.so.1 => /lib/librt.so.1 (0x74fc0000)
/lib/ld-linux-armhf.so.3 (0x76faa000)
libGAL.so => /usr/lib/libGAL.so (0x74ebc000)
libEGL.so.1 => /usr/lib/libEGL.so.1 (0x74e9d000)
libVSC.so => /usr/lib/libVSC.so (0x74ddb000)
libpcre.so.1 => /usr/lib/libpcre.so.1 (0x74d8c000)
libXdamage.so.1 => /usr/lib/libXdamage.so.1 (0x74d7a000)
libXfixes.so.3 => /usr/lib/libXfixes.so.3 (0x74d66000)
libXext.so.6 => /usr/lib/libXext.so.6 (0x74d48000)
libX11.so.6 => /usr/lib/libX11.so.6 (0x74c2e000)
libxcb.so.1 => /usr/lib/libxcb.so.1 (0x74c01000)
libXau.so.6 => /usr/lib/libXau.so.6 (0x74bef000)
libXdmcp.so.6 => /usr/lib/libXdmcp.so.6 (0x74bdb000)
The offending line in the qml code is:
import QtQuick.Controls 2.0
Without any success, I have already added the following code to the recipe:
+IMAGE_INSTALL_append = " qtquickcontrols"
The directory /usr/lib/qt5/qml/QtQuick is present and contains libqtquick2plugin.so
Adding this directory to the LD_LIBRARY_PATH prior to starting the application does not solve the issue though.
I have exported:
export LD_LIBRARY_PATH=/usr/lib/qt5/qml/QtQuick.2:/usr/lib/qt5/qml/QtQuick
I wonder what file could be missing.
Can please somebody provide pointers on how to debug this?
To test Amfasis idea, I now also export
export QML2_IMPORT_PATH="/usr/lib/qt5/qml"
prior to starting the application in the same shell.
ls /usr/lib/qt5/qml/
Qt
QtGraphicalEffects
QtLocation
QtPositioning
QtQml
QtQuick
QtQuick.2
QtTest
QtWebChannel
QtWebEngine
builtins.qmltypes
Nevertheless, the error stays the same.
Looks as if I was missing libQt5QuickControls.so
I'll dig into this...

Answer 1

For future reference:
The idea is to explicitly state a dependency in yocto.
This can be achieved by adding
RDEPENDS_${PN} = "qtquickcontrols2 \
qtquickcontrols2-mkspecs \
"
Then, the dependency will be compiled and installed.
It is not enough, though, to add the following (which I had before already):
DEPENDS = "qtquickcontrols2"

Answer 2

I followed this answer:
sudo apt install qml-module-qtquick-controls2
Note the 2 at the end. By default minuet package installs qml-module-qtquick-controls.
And fixed the errors running minuet 19.12.3-0ubuntu1 on Ubuntu 20.04:
[...]
QQmlApplicationEngine failed to load component
qrc:/Main.qml:24 module "QtQuick.Controls" version 2.0 is not installed