How to consume public header files of a generic qml_module in a project specific qml_module

[Andreas Schacherbauer]

Hi!
We have a bit more complex setup with a generic library that defines (multiple) qml_modules. These qml_modules are then consumed in projects. Projects are again separated into multiple qml_modules. The problem arises while we wanted to transition to QmlProject files from CMake (as the Qt for MCUs CMake API is deprecated). The project specific qml_module has C++ types that need to be used in Qml, hence we define a InterfaceFiles node in the QmlProject like the following:

    InterfaceFiles {
        files: [
            "include/path/to/a/InterfaceHeader.h"
        ]
        MCU.qmlImports: [
            "com.company.generic.component"
        ]
    }

The compiler fails to resolve header includes in InterfaceHeader.h as the qmlprojectgenerator only gets CMake INCLUDE_DIRECTORIES of the CMake targets of the project feature qml_module passed as the --include-dirs parameter. The feature lib (created with qul_add_target(TARGET_NAME QML_PROJECT feature.qmlproject) does link to the generic qml_module with a target_link_libraries() call but this is too late for the internal workings of the qul_add_target macro.

Somehow the QmlProject is missing a way to tell it which other qml_modules need to be linked/considered. The qul_add_target macro at some point internally is only evaluating the direct INCLUDE_DIRECTORIES which does not include the include directories of transitive dependencies.

Here is another short overview of the structure:

* generic-library
    - output: qml_module

* project
    * feature-a
        - defines qml_module
            - depends on qml_module of generic-library
            - ERROR: the interface header files of this of this qml_module are unable to include headers of the generic-library when using .qmlproject files. 
    * feature-xxx
        - defines qml_module
            - depends on qml_module of generic-library
            - additionally might depend on another feature of the project
    * project-lib
        - depends on all features 
    * project-app
        - depends on project-lib

Thx,
Andi