windeployqt.exe looks for library in the wrong place

Mesrine

Hi everyone.

I have a console application and I use cmake-deployment-api to deploy the qt dependencies.
This works well for linux and macos,but not for windows.
For windows the cmake install step

Run cmake --install .

returns

...
-- Installing: D:/a/_temp/install/lib/cmake/Qt6Mqtt/Qt6MqttConfigVersionImpl.cmake
-- Installing: D:/a/_temp/install/lib/Qt6Mqtt.lib
-- Installing: D:/a/_temp/install/bin/Qt6Mqtt.dll
-- Installing: D:/a/_temp/install/lib/cmake/Qt6Mqtt/Qt6MqttTargets.cmake
-- Installing: D:/a/_temp/install/lib/cmake/Qt6Mqtt/Qt6MqttTargets-release.cmake
-- Installing: D:/a/_temp/install/lib/cmake/Qt6Mqtt/Qt6MqttVersionlessTargets.cmake
-- Installing: D:/a/_temp/install/./modules/Mqtt.json
...
-- Running Qt deploy tool for D:/a/_temp/build/outConsolidator.exe in working directory 'D:/a/_temp/install'
'D:/a/outConsolidator/Qt/6.6.0/msvc2019_64/bin/windeployqt.exe' 'D:/a/_temp/build/outConsolidator.exe' '--dir' '.' '--libdir' 'bin' '--plugindir' 'plugins' '--force'
Unable to find dependent libraries of D:\a\outConsolidator\Qt\6.6.0\msvc2019_64\bin\Qt6Mqtt.dll :Cannot open 'D:/a/outConsolidator/Qt/6.6.0/msvc2019_64/bin/Qt6Mqtt.dll': The system cannot find the file specified.
CMake Error at D:/a/outConsolidator/Qt/6.6.0/msvc2019_64/lib/cmake/Qt6Core/Qt6CoreDeploySupport.cmake:475 (message):
  Executing D:/a/outConsolidator/Qt/6.6.0/msvc2019_64/bin/windeployqt.exe
  failed: 1
Call Stack (most recent call first):
  .qt/deploy_outConsolidator_67a0058dfd.cmake:5 (qt6_deploy_runtime_dependencies)
  cmake_install.cmake:71 (include)

The thing is I have not installed QtMqtt as part of Qt installation.

My CMake project downloads and build Qt6Mqtt.dll.
My project also install the library as shown on the cmake install step above in D:/a/_temp/install/bin/Qt6Mqtt.dll.

So, It seems windeployqt.exe detects that the application depends on Qt6Mqtt.dll but it is looking at the bin folder of the Qt installation directory.

Interestingly I also have a qtquick application that uses the same libraries and cmake-deployment-api.
But there everything works well.

So any help clarifying why windeployqt.exe gives that error and how to fix it will be much appreciated.

Christian Ehrlicher

windeployqt (as also qmake and the cmake scripts) expects that all Qt stuff is innstalled with the same prefix which is not in your case.
So install the Qt6Mqtt stuff with the same prefix as the rest.

Mesrine

@Christian-Ehrlicher

Thanks, do you know how to install Qt6Mqtt on a GitHub runner?
And how it is that works for the qtquick application and not for the console application.
For the qtquick application, Qt6Mqtt is not installed as part of Qt and works.
For the Qt-Windows installation are the .dlls installed in the bin folder or in a lib folder?
If installed in a lib folder windeployqt.exe is looking also in the wrong folder.

Mesrine

@Mesrine
According to this. I should pass --ignore-library-errors.
But the CMake API it seems that do not allow it.
Where is the source code of windeployqt for qt 6.5.0?

cristian-adam

I've opened up https://bugreports.qt.io/browse/QTBUG-116551

I think the CMake API should provide a way to specify arguments to windeployqt and macdeployqt.

Mesrine

@cristian-adam Thanks, It is a nice thing to have on the CMake API.

Mesrine

@Mesrine

It seems that the generic deploy tool uses file(GET_RUNTIME_DEPENDENCIES) of CMake.

The Qt cmake API allows setting variables like PRE_INCLUDE_REGEXES .

So, I am wondering how to use something like

if(QTDEPLOY)
		qt_generate_deploy_app_script(
			TARGET ${example}
			OUTPUT_SCRIPT deploy_script
			PRE_INCLUDE_REGEXES "${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}/*"
			)

		install(SCRIPT ${deploy_script})
endif(QTDEPLOY)

I want to set PRE_INCLUDE_REGEXES to the path the MQTT library was installed.
The best will be to use DIRECTORIES but I do not see how to pass this from the QT CMake API.

cristian-adam

This is only available for Linux, on Windows and macOS the windeployqt and macdeployqt tools are used.

Woud be nice to have the generic deploy tool, but AFAIK it's not possible.

Please do create a bugreport at https://bugreports.qt.io/

Mesrine

@Mesrine This does not make much sense because windeploy.exe what it does is to populate the install folder with the QT dependencies.
Still, I have not found the windeploy source code to see where it is getting that mqttlibrary path.

Mesrine

@cristian-adam I see for Linux it is called 'generic Qt deploy tool' and use file(GET_RUNTIME_DEPENDENCIES).
Thanks.

cristian-adam

https://code.qt.io/cgit/qt/qtbase.git/tree/src/tools/windeployqt ist the place for the windeployqt source code.

Mesrine

@cristian-adam
It seems this part checks if the library is called "Qt6Something" and adds the Qt bin installation directory to the path for the next iteration of the function.