记录一次ROS2消息BUG ImportError rosidl_generator_c.so: undefined symbol

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BUG表现如下 自定义消息，编译不报错，运行就出错

Traceback (most recent call last):
  File "/opt/ros/foxy/lib/python3.8/site-packages/rosidl_generator_py/import_type_support_impl.py", line 46, in import_type_support
    return importlib.import_module(module_name, package=pkg_name)
  File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "", line 1014, in _gcd_import
  File "", line 991, in _find_and_load
  File "", line 975, in _find_and_load_unlocked
  File "", line 657, in _load_unlocked
  File "", line 556, in module_from_spec
  File "", line 1166, in create_module
  File "", line 219, in _call_with_frames_removed
ImportError: /home/ros2/code/town_ws/install/village_interfaces/lib/libvillage_interfaces__rosidl_generator_c.so: undefined symbol: sensor_msgs__msg__Image__init

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/ros2/code/town_ws/install/village_li/lib/village_li/li4_node", line 11, in 
    load_entry_point('village-li==0.0.0', 'console_scripts', 'li4_node')()
  File "/home/ros2/code/town_ws/install/village_li/lib/python3.8/site-packages/village_li/li4.py", line 46, in main
    node = Li4Node()  # 新建一个节点
  File "/home/ros2/code/town_ws/install/village_li/lib/python3.8/site-packages/village_li/li4.py", line 23, in __init__
    self.borrow_server = self.create_service(BorrowMoney,"borrow_money",self.borrow_money_callback)
  File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/node.py", line 1295, in create_service
    check_for_type_support(srv_type)
  File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/type_support.py", line 29, in check_for_type_support
    msg_type.__class__.__import_type_support__()
  File "/home/ros2/code/town_ws/install/village_interfaces/lib/python3.8/site-packages/village_interfaces/srv/_borrow_money.py", line 316, in __import_type_support__
    module = import_type_support('village_interfaces')
  File "/opt/ros/foxy/lib/python3.8/site-packages/rosidl_generator_py/import_type_support_impl.py", line 48, in import_type_support
    raise UnsupportedTypeSupport(pkg_name)
rosidl_generator_py.import_type_support_impl.UnsupportedTypeSupport: Could not import 'rosidl_typesupport_c' for package 'village_interfaces'

原因：

自定义消息未添加对其他消息的依赖

解决办法，添加依赖在CMakeists.txt中

find_package(rosidl_default_generators REQUIRED)
rosidl_generate_interfaces(${PROJECT_NAME}
  #---msg---
  "msg/Novel.msg"
  #---srv---
  "srv/BorrowMoney.srv"
  "srv/SellNovel.srv"
   DEPENDENCIES std_msgs sensor_msgs
 )