Undefined references when linking MicroROS with an SMT32CubeMX project

Describe the bug

I am trying to integrate MicroROS in an existing STM32CubeMX CMake project. Linking the final binary fails with errors about unresolved references in librmw_microxrcedds.a to symbols in Micro XRCE-DDS Client and to symbols in Micro XRCE-DDS typesupport:

../../install/lib/librmw_microxrcedds.a(rmw_client.c.obj): in function `rmw_destroy_client':
MicroROS/microros/rmw_microxrcedds/rmw_microxrcedds_c/src/rmw_client.c:220:(.text.rmw_destroy_client+0x9e): undefined reference to `uxr_buffer_cancel_data'
...
../../install/lib/libstd_msgs__rosidl_typesupport_c.a(int32__type_support.cpp.obj):
./build/std_msgs/rosidl_typesupport_c/std_msgs/msg/int32__type_support.cpp:67:(.data._ZN8std_msgs3msg20rosidl_typesupport_cL31_Int32_message_typesupport_dataE+0x0): undefined reference to `rosidl_typesupport_introspection_c__get_message_type_support_handle__std_msgs__msg__Int32'

Everything, including the main project, is a colcon package built with Ninja. The project layout is:

<project root>
├── Core
│   ├── Inc
│   │   └── <CubeMX generated headers>
│   └── Src
│       ├── <CubeMX generated sources>
│       ├── cubemx_uart_transport.c
│       ├── microros_allocator.c
│       └── main.c
├── MicroROS
│   ├── microros
│   │   └── <MicroROS packages>
│   ├── ros2
│   │   └── <ROS2 packages>
│   └── microros.repos
├── App
│   └── int32_publisher
│       ├── src
│       ├── CMakeLists.txt
│       └── package.xml
├── <other Cubemx generated files>
├── colcon.meta
├── colcon.pkg
└── CMakeLists.txt

The default task in main.c initializes MicroROS, calls into application packages, which are built as static libraries, to initialize node(s) etc., and then calls rclc_executor_spin_some() in a loop.

The project is built with colcon build --packages-up-to cubemx-microros-cmake --packages-ignore-regex=".*_cpp" --metas ./colcon.meta --merge-install --paths . --base-paths ./MicroROS ./App --cmake-args -G Ninja --no-warn-unused-cli -DCMAKE_POSITION_INDEPENDENT_CODE=OFF -DTHIRDPARTY=ON -DBUILD_SHARED_LIBS=OFF -DBUILD_TESTING=OFF -DCMAKE_BUILD_TYPE=Debug -DCMAKE_TOOLCHAIN_FILE="$(pwd)/cmake/gcc-arm-none-eabi.cmake"

Relevant parts of CMakeLists.txt:

Application package(s):

find_package(ament_cmake REQUIRED)
find_package(ament_cmake_ros REQUIRED)

find_package(rclc REQUIRED)
find_package(std_msgs REQUIRED)

# Basic MicroROS publisher                                                                  
add_library(int32_publisher STATIC
  src/int32_publisher.c
)
ament_target_dependencies(int32_publisher
  std_msgs rclc
)

# ...

install(
  TARGETS int32_publisher
  EXPORT  export_${PROJECT_NAME}
  ARCHIVE DESTINATION lib
)

ament_export_targets(
  export_${PROJECT_NAME} HAS_LIBRARY_TARGET
)
ament_export_dependencies(std_msgs rclc)

ament_package()

Main CMakeLists.txt:

find_package(microxrcedds_client REQUIRED)
find_package(rmw_microxrcedds REQUIRED)
find_package(rcutils REQUIRED)
find_package(rcl REQUIRED)
find_package(rclc REQUIRED)
find_package(int32_publisher REQUIRED)

add_executable(${CMAKE_PROJECT_NAME})

# ...

target_link_libraries(${CMAKE_PROJECT_NAME}
    int32_publisher::int32_publisher
    ${rmw_microxrcedds_LIBRARIES}
    rclc::rclc rcl::rcl rcutils::rcutils
)

I also tried to make the top level project an ament_cmake_ros package using ament_target_dependencies(), to no avail.

Expected behavior:

Linking the binary works without errors, all required MicroROS libraries are passed to the linker in the correct order.

System information:

OS: FreeRTOS+POSIX, CMSIS v2
ROS 2 Humble

This is how the linker is invoked from the CMake-generated Ninja build files:

arm-none-eabi-g++ -mcpu=cortex-m7 -mfpu=fpv5-d16 -mfloat-abi=hard -Wall -Wextra -Wpedantic -fdata-sections -ffunction-sections -O0 -g3 -DCLOCK_MONOTONIC=1 -fno-rtti -fno-exceptions -fno-threadsafe-statics -g -mcpu=cortex-m7 -mfpu=fpv5-d16 -mfloat-abi=hard -T "STM32F767ZITx_FLASH.ld" --specs=nano.specs -Wl,-Map=microros-cubemx-cmake.map -Wl,--gc-sections -Wl,--print-memory-usage $OBJECTS -o microros-cubemx-cmake.elf ../../install/lib/libint32_publisher.a ../../install/lib/librmw_microxrcedds.a ../../install/lib/librcutils.a ../../install/lib/librcutils.a ../../install/lib/librosidl_runtime_c.a ../../install/lib/librmw.a ../../install/lib/librcutils.a ../../install/lib/librosidl_runtime_c.a ../../install/lib/librcutils.a ../../install/lib/librosidl_runtime_c.a ../../install/lib/librmw.a ../../install/lib/librcutils.a ../../install/lib/librosidl_runtime_c.a ../../install/lib/librmw.a ../../install/lib/librosidl_runtime_c.a ../../install/lib/librcutils.a ../../install/lib/librosidl_typesupport_microxrcedds_c.a ../../install/lib/librosidl_runtime_c.a ../../install/lib/librclc.a ../../install/lib/librcl.a ../../install/lib/librcutils.a ../../install/lib/librcl_action.a ../../install/lib/librcl.a ../../install/lib/librcl_interfaces__rosidl_typesupport_introspection_c.a ../../install/lib/librcl_interfaces__rosidl_typesupport_c.a ../../install/lib/librcl_interfaces__rosidl_generator_c.a ../../install/lib/librcl_logging_interface.a ../../install/lib/librmw_microxrcedds.a ../../install/lib/librcutils.a ../../install/lib/librosidl_runtime_c.a ../../install/lib/librmw.a ../../install/lib/librcutils.a ../../install/lib/librosidl_runtime_c.a ../../install/lib/librmw.a ../../install/lib/librosidl_typesupport_microxrcedds_c.a ../../install/lib/librmw.a ../../install/lib/libaction_msgs__rosidl_typesupport_introspection_c.a ../../install/lib/libunique_identifier_msgs__rosidl_typesupport_introspection_c.a ../../install/lib/libaction_msgs__rosidl_typesupport_c.a ../../install/lib/libaction_msgs__rosidl_generator_c.a ../../install/lib/libunique_identifier_msgs__rosidl_typesupport_c.a ../../install/lib/libunique_identifier_msgs__rosidl_generator_c.a ../../install/lib/libstd_msgs__rosidl_typesupport_introspection_c.a ../../install/lib/libbuiltin_interfaces__rosidl_typesupport_introspection_c.a ../../install/lib/librosidl_typesupport_introspection_c.a ../../install/lib/libstd_msgs__rosidl_typesupport_c.a ../../install/lib/libstd_msgs__rosidl_generator_c.a ../../install/lib/libbuiltin_interfaces__rosidl_typesupport_c.a ../../install/lib/libbuiltin_interfaces__rosidl_generator_c.a ../../install/lib/librosidl_typesupport_c.a ../../install/lib/librosidl_runtime_c.a ../../install/lib/librcutils.a -lm -lc -lnosys

micro-ROS / rmw_microxrcedds

Undefined references when linking MicroROS with an SMT32CubeMX project #309