Qt 6.9 ds-build conflicts with ds-src

Yihua Liu

After I upgrade my Qt from 6.8.2 to 6.9.0, the CMake configuration fails:

[cmake] CMake Error at qmlcomponents:33 (add_subdirectory):
[cmake]   The binary directory
[cmake] 
[cmake]     E:/Documents/GitHub/Suis/build/Desktop_Qt_6_9_0_MSVC2022_64bit-Debug/_deps/ds-build
[cmake] 
[cmake]   is already used to build a source directory.  It cannot be used to build
[cmake]   source directory
[cmake] 
[cmake]     E:/Documents/GitHub/Suis/build/Desktop_Qt_6_9_0_MSVC2022_64bit-Debug/_deps/ds-src
[cmake] 
[cmake]   Specify a unique binary directory name.
[cmake] Call Stack (most recent call first):
[cmake]   CMakeLists.txt:117 (include)
[cmake] 
[cmake] 
[cmake] -- Configuring incomplete, errors occurred!

I found that the _deps directory does not exist in my Qt 6.8.2 build but exists in my Qt 6.9.0 build. The qmlcomponent file was automatically generated by Qt Design Studio:

### This file is automatically generated by Qt Design Studio.
### Do not change

message("Building designer components.")

set(QT_QML_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/qml")

include(FetchContent)
FetchContent_Declare(
    ds
    GIT_TAG qds-4.7
    # https://github.com/qt-labs/qtquickdesigner-components
    GIT_REPOSITORY https://code.qt.io/qt-labs/qtquickdesigner-components.git
)

FetchContent_GetProperties(ds)
# Calling FetchContent_Populate(ds) is deprecated, call FetchContent_MakeAvailable(ds) instead.
# Policy CMP0169 can be set to OLD to allow FetchContent_Populate(ds) to be called directly for now,
# but the ability to call it with declared details will be removed completely in a future version.
FetchContent_MakeAvailable(ds)

target_link_libraries(${CMAKE_PROJECT_NAME} PRIVATE
    QuickStudioComponentsplugin
    QuickStudioEffectsplugin
    QuickStudioApplicationplugin
    FlowViewplugin
    QuickStudioLogicHelperplugin
    QuickStudioMultiTextplugin
    QuickStudioEventSimulatorplugin
    QuickStudioEventSystemplugin
)

add_subdirectory(${ds_SOURCE_DIR} ${ds_BINARY_DIR})

target_compile_definitions(${CMAKE_PROJECT_NAME} PRIVATE
  BULD_QDS_COMPONENTS=true
)

I only changed line 20 to avoid the deprecated FetchContent_Populate, but line 33 is not changed. How to fix this error?

Yihua Liu

@Christian-Ehrlicher Hi, I found that if I downgrade CMake to 3.28 and change line 20 back to FetchContent_Populate then the CMake build can run successfully. I learned that different from FetchContent_Populate, FetchContent_MakeAvailable not only downloads and unpacks the content but also automatically adds it to my build by calling add_subdirectory() internally. Aftter I remove add_subdirectory(${ds_SOURCE_DIR} ${ds_BINARY_DIR}) then the CMake build can run successfully

Christian Ehrlicher

Use a clean build dir and make sure you did not do an in-source build by accident (aka remove all build artifacts from your source dir).

Yihua Liu

@Christian-Ehrlicher Hi, I clean the build dir and redo the build but the error still exists

Christian Ehrlicher

There must be some old cmake files from your old build.

Yihua Liu

@Christian-Ehrlicher Hi, I found that if I downgrade CMake to 3.28 and change line 20 back to FetchContent_Populate then the CMake build can run successfully. I learned that different from FetchContent_Populate, FetchContent_MakeAvailable not only downloads and unpacks the content but also automatically adds it to my build by calling add_subdirectory() internally. Aftter I remove add_subdirectory(${ds_SOURCE_DIR} ${ds_BINARY_DIR}) then the CMake build can run successfully