[BUG] Build with Qt6 seems to fail

[ConiKost]

Description
If -DPROJECTEUR_QT_VERSION=6 is being used, to build Projecteur with Qt6, it will fail, as it can't find the needed packages. This seems not be an issue with installed packages, but instead, the checks seems not correct.

Even, that -DPROJECTEUR_QT_VERSION=6 is set to Qt6, you can see, that ist still tries to get Qt5 additional.

    -- Detecting CXX compile features - done
    CMake Error at cmake/modules/Translation.cmake:1 (find_package):
      By not providing "FindQt5.cmake" in CMAKE_MODULE_PATH this project has
      asked CMake to find a package configuration file provided by "Qt5", but
      CMake did not find one.

Looking further, in modules/Translation.cmake is a check, which is hardcoded for Qt5 and gets also used, when trying to use Qt6.

find_package(Qt5 REQUIRED COMPONENTS Core)

As a result, more further errors happens:

    -- Found WrapVulkanHeaders: /usr/include
    CMake Error at /usr/lib64/cmake/Qt6Qml/Qt6QmlMacros.cmake:2415 (message):
       qt_generate_foreign_qml_types() is only available in Qt 6.

Looking into the code of Qt6QmlMacros clearly shows:

    if(NOT QT_NO_CREATE_VERSIONLESS_FUNCTIONS)
        if(QT_DEFAULT_MAJOR_VERSION EQUAL 6)
            function(qt_generate_foreign_qml_types)
                qt6_generate_foreign_qml_types(${ARGV})
            endfunction()
        else()
            message(FATAL_ERROR "qt_generate_foreign_qml_types() is only available in Qt 6.")
        endif()
    endif()

So apparently, the "bad" Qt5 check likely set QT_DEFAULT_MAJOR_VERSION to 5 despite trying to use Qt6.

To Reproduce

• Install only Qt6 libs
• Compile Projecteur with -DPROJECTEUR_QT_VERSION=6

Expected behavior
Compilation works with Qt6

Desktop/Linux Environment (please complete the following information):

• Linux Distribution and Version: Gentoo Linux (Newest rolling release)
• Desktop/Window Manager and Version: i3 4.23
• Did you built Projecteur yourself?: Y
• What is the output of projecteur -f ?: N/A
• What is the output of projecteur -d ?: N/A

[jahnf]

@ConiKost thank you for reporting I will look into it.

[a17r]

After using the following patch to build with Qt6: https://gist.github.com/a17r/1d2e0f2e3876331e5f547fee20573ad4

I'm getting errors like these:

src/asynchronous.h:148:35: error: no matching function for call to ‘makeSafeCallback(HIDPP::FeatureSet*, HIDPP::FeatureSet::getFirmwareCount(std::function<void(HidppConnectionInterface::MsgResult, unsigned char, unsigned char)>)::<lambda(HIDPP::FeatureSet::MsgResult, uint8_t)>, bool&)’
  148 |     return async::makeSafeCallback(static_cast<T*>(this), std::forward<F>(f), autoConnection);
      |            ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

src/asynchronous.h:154:18: error: no matching function for call to ‘invoke(HIDPP::FeatureSet*, HIDPP::FeatureSet::getFeatureIndex(HIDPP::FeatureCode, std::function<void(HidppConnectionInterface::MsgResult, unsigned char)>)::<lambda()>)’
  154 |     async::invoke(static_cast<T*>(this), std::forward<F>(function));
      |     ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

src/asynchronous.h:46:13: error: no match for call to ‘(SubHidppConnection::subDeviceInit()::<lambda(SubHidppConnection::ReceiverState)>::<lambda(SubHidppConnection::PresenterState)>) (QTemplatedMetaMethodReturnArgument<void>&, SubHidppConnection::PresenterState)’
   46 |       lambda(std::forward<decltype(args)>(args) ...);
      |       ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[ConiKost]

@jahnf any news on this?

[ConiKost]

@jahnf ping

[ConiKost]

@jahnf ping 2

[ConiKost]

Sadly this has been not fixed, so we are going to drop Projecteur from Gentoo Linux.

[olifre]

The patch:
https://gist.github.com/olifre/88791e881efd570673a31ea53bf64c35
(includes the patch by @a17r ) fixes compilation with Qt6 for me. While most changes were straightforward and are human-made by me, the change in asynchronous.h was created with the help of AI (but reviewed by me).

I could also put this into a PR, but I am not sure the repo maintainer @jahnf is still active?

[olifre]

PR now opened, hoping to ease the life of the maintainer.

[jahnf]

thanks for the PR, I guess this will need an version bump, an update to the docs and CI pipelines in general will be necessary, also older distributions not supported anymore out of the box. will review in the next few days