error building package with interfaces due to member_of_group rosidl_interface_packages location in package.xml

Question

I've been trying to establish communication between 2 nodes and shared library .so. Encountered an error:

Packages installing interfaces must include '<member_of_group>rosidl_interface_packages</member_of_group>' in their package.xml Call Stack (most recent call first): CMakeLists.txt:24 (rosidl_generate_interfaces)

my CMakeLists.txt:

    cmake_minimum_required(VERSION 3.5)
project(parameter_subscriber)

# Default to C99
if(NOT CMAKE_C_STANDARD)
  set(CMAKE_C_STANDARD 99)
endif()

# Default to C++14
if(NOT CMAKE_CXX_STANDARD)
  set(CMAKE_CXX_STANDARD 14)
endif()

if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
  add_compile_options(-Wall -Wextra -Wpedantic)
endif()

# Find dependencies
find_package(ament_cmake REQUIRED)
find_package(rclcpp REQUIRED)
find_package(rosidl_default_generators REQUIRED)

# Generate messages
rosidl_generate_interfaces(${PROJECT_NAME}
  "msg/Parameters.msg"
)

# Add executable
add_executable(subscriber src/subscriber.cpp)
ament_target_dependencies(subscriber rclcpp)
rosidl_target_interfaces(subscriber ${PROJECT_NAME} "rosidl_typesupport_cpp")

# Specify the path to the shared library
set(LIBBEBOT_PATH "${CMAKE_CURRENT_SOURCE_DIR}/../libbebot.so")

# Link the shared library
target_link_libraries(subscriber ${LIBBEBOT_PATH})

install(TARGETS
  subscriber
  DESTINATION lib/${PROJECT_NAME})

ament_export_dependencies(rosidl_default_runtime)

if(BUILD_TESTING)
  find_package(ament_lint_auto REQUIRED)
  ament_lint_auto_find_test_dependencies()
endif()

ament_package()

my package.xml:

<?xml version="1.0"?>
<package format="3">
  <name>parameter_subscriber</name>
  <version>0.0.0</version>
  <description>TODO: Package description</description>

  <license>TODO: License declaration</license>

  <buildtool_depend>ament_cmake</buildtool_depend>
  <build_depend>rosidl_default_generators</build_depend>
  <exec_depend>rosidl_default_runtime</exec_depend>
  <build_depend>rclcpp</build_depend>
  <exec_depend>rclcpp</exec_depend>
  
  <test_depend>ament_lint_auto</test_depend>
  <test_depend>ament_lint_common</test_depend>

  <export>
    <build_type>ament_cmake</build_type>
    <member_of_group>rosidl_interface_packages</member_of_group>
  </export>
</package>

What can be an issue here? Thank you for your time!

Answer 1

The <member_of_group> tag should be at the top level not inside the <exports> tag.

The format spec is here: https://ros.org/reps/rep-0149.html#group-dependencies-and-memberships

For example:

https://github.com/ros2/geometry2/blob/381d381739d008f83c2ebdf39034d46a19ea364e/tf2_msgs/package.xml#L29

Answer 2

The error message says:

Packages installing interfaces must include '<member_of_group>rosidl_interface_packages</member_of_group>' in their package.xml Call Stack (most recent call first): CMakeLists.txt:24 (rosidl_generate_interfaces)

You do have <member_of_group>rosidl_interface_packages</member_of_group> in your package.xml, but it's in the wrong place. It should not be inside <export>...</export>. It should be:

<?xml version="1.0"?>
<package format="3">
  <name>parameter_subscriber</name>
  <version>0.0.0</version>
  <description>TODO: Package description</description>

  <license>TODO: License declaration</license>

  <buildtool_depend>ament_cmake</buildtool_depend>
  <build_depend>rosidl_default_generators</build_depend>
  <exec_depend>rosidl_default_runtime</exec_depend>
  <build_depend>rclcpp</build_depend>
  <exec_depend>rclcpp</exec_depend>
  
  <test_depend>ament_lint_auto</test_depend>
  <test_depend>ament_lint_common</test_depend>

  <member_of_group>rosidl_interface_packages</member_of_group>

  <export>
    <build_type>ament_cmake</build_type>
  </export>
</package>

Edit: well, Tully beat me by 1 minute!