qt_generate_deploy_qml_app_script generates script with empty include()

[rhvonlehe]

Here's a CMakeLists.txt that is attempting to use the CMake macro qt_generate_deploy_qml_app_script. I'm following the blog here [1]. Everything seems fine until the install stage, where it seems the deploy script is missing some environment variables being set. The main one I've discovered so far is ${QT_DEPLOY_SUPPORT}. This seems to be something the Core library should set at some point, but it's empty in my case resulting in a deploy script that errors out.

find_package(Qt6 COMPONENTS Core Gui Qml REQUIRED)
qt_standard_project_setup()

set(QML_FILES
    qml/Intro.qml
    qml/RootWindow.qml
)

set(CPP_FILES
    QWarClientApp.cpp
)

qt_add_executable(QWarClient
    main.cpp
)

qt_add_qml_module(QWarClient
    VERSION 1.0
    URI "QWarClient"
    QML_FILES ${QML_FILES}
    SOURCES ${CPP_FILES}
)

target_link_libraries(QWarClient
    PRIVATE
    Qt6::Core
    Qt6::Gui
    Qt6::Qml
)

install(TARGETS QWarClient
    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
)

qt_generate_deploy_qml_app_script(
    TARGET QWarClient
    FILENAME_VARIABLE deploy_script
    NO_UNSUPPORTED_PLATFORM_ERROR
)

message("deploy script name: ${deploy_script}")
message("qt_deploy_support: ${QT_DEPLOY_SUPPORT}")
install(SCRIPT ${deploy_script})

the generated deploy script ends up looking like this:

include()
_qt_internal_show_skip_runtime_deploy_message("static Qt libs")
_qt_internal_show_skip_qml_runtime_deploy_message()

Is there something I'm missing here?

[1] https://www.qt.io/blog/cmake-deployment-api

[rhvonlehe]

@rhvonlehe If I remove the NO_UNSUPPORTED_PLATFORM_ERROR option from qt_generate_deploy_qml_app_script then I get a CMake configuration error like this:

CMake Error at C:/.conan/ac5814/1/lib/cmake/Qt6Qml/Qt6QmlMacros.cmake:3088 (message):
  Support for installing runtime dependencies is not implemented for this
  target platform (Windows, static Qt libs).
Call Stack (most recent call first):
  C:/.conan/ac5814/1/lib/cmake/Qt6Qml/Qt6QmlMacros.cmake:3104 (qt6_generate_deploy_qml_app_script)
  client/CMakeLists.txt:37 (qt_generate_deploy_qml_app_script)

I'm confused about why it thinks I'm trying to use static Qt libs.

Below is my conanfile.py

from conans import ConanFile
from conan.tools.cmake import CMakeToolchain, CMakeDeps, CMake

class QWar(ConanFile):
    name = "QWar"
    version = "0.1"
    settings = "os", "compiler", "build_type", "arch"
    requires = "boost/1.77.0", "qt/6.4.2"
    generators = "CMakeToolchain", "CMakeDeps"


    def configure(self):
        # requiring qt doesn't get all modules, some have to be explicitly added as
        # shown here
        self.options["qt"].qtdeclarative = True
        self.options["qt"].shared = True

    def build(self):
        cmake = CMake(self)
        cmake.configure()
        cmake.build()

[rhvonlehe]

@rhvonlehe Some more context:

There's an important variable that gets checked in Qt6QmlMacros.cmake called QT6_IS_SHARED_LIBS_BUILD. If this CMake variable is not set, it will error out as shown in my previous posts because it assumes the Qt6 build created static libraries. The only place I see QT6_IS_SHARED_LIBS_BUILD being set to true is in Qt6CoreConfigExtras.cmake. However, when I run cmake --trace I don't ever see that module being used.

The only path to getting that variable set is to have these cmake modules included in this order:
QtSetup.cmake --> QtBuild.cmake ->> QtModuleHelpers.cmake --> Qt6CoreConfigExtras.cmake

I don't know when or how those are supposed to get included and by whom.

Does anyone have any knowledge of this?

EDIT: I can see now that QtSetup and QtBuild are CMake modules that are only supposed to be used for the actual building of Qt6. So my question now becomes, why is this variable QT6_IS_SHARED_LIBS_BUILD being relied on when invokingqt_generate_deploy_qml_app_script from a user program when a user program's CMake will never invoke the modules that set that variable?

[jobor]

@rhvonlehe Qt6CoreConfigExtras.cmake is supposed to be included by the Qt6Core CMake package.
The find_package call at the top of your CMakeLists.txt file should take care of that.

Please configure your project with --trace-expand --trace-redirect=cmake.trace, and make that trace file available. Then we can have a look why Qt6CoreConfigExtras.cmake is not loaded for you.

[jobor]

For reference, here's the bug report Rich created for this issue: https://bugreports.qt.io/browse/QTBUG-113769