Own message generator and building tests

Next Generation ROS
1

For my C# wrapper I wrote my own message generator and implemented a rosidl_generator_cs package ( https://github.com/firesurfer/rosidl_generator_cs ).

This works fine when doing a normal build but today I tried building ros2 with the --build-tests option. With this option the build fails at the builtin_interfaces package.

Scanning dependencies of target builtin_interfaces__py
Scanning dependencies of target generate_cs_messages_Time
make[2]: *** Keine Regel vorhanden, um das Ziel „/home/firesurfer/workspace/ros2_ws/src/ros2/common_interfaces/builtin_interfaces/ros2cs_message_generator“, 
benötigt von „CMakeFiles/generate_cs_messages_Duration“, zu erstellen.  Schluss.
CMakeFiles/Makefile2:520: die Regel für Ziel „CMakeFiles/generate_cs_messages_Duration.dir/all“ scheiterte
make[1]: *** [CMakeFiles/generate_cs_messages_Duration.dir/all] Fehler 2
make[1]: *** Es wird auf noch nicht beendete Prozesse gewartet...
make[2]: *** Keine Regel vorhanden, um das Ziel „/home/firesurfer/workspace/ros2_ws/src/ros2/common_interfaces/builtin_interfaces/ros2cs_message_generator“, 
benötigt von „CMakeFiles/generate_cs_messages_Time“, zu erstellen.  Schluss.
CMakeFiles/Makefile2:1378: die Regel für Ziel „CMakeFiles/generate_cs_messages_Time.dir/all“ scheiterte
make[1]: *** [CMakeFiles/generate_cs_messages_Time.dir/all] Fehler 2

Only english (sry that I’m working on a german system) the error is (translated):

No rule exists to create the target „/home/firesurfer/workspace/ros2_ws/src/ros2/common_interfaces/builtin_interfaces/ros2cs_message_generator“, 
needed from „CMakeFiles/generate_cs_messages_Duration“, Exit.
CMakeFiles/Makefile2:520: the rule for target „CMakeFiles/generate_cs_messages_Duration.dir/all“ failed.

Then it says the same for the Time message.
I’ve got absolutely no idea why everything works fine if I’m building without tests but fails with tests enabled.

2

When you build with --build-tests, the BUILD_TESTING cmake option is set to true.

From looking at your project, I think you are only appending the target to the list of message targets if BUILD_TESTING is true:

That might explain why it’s only failing when you build with --build-testing

As for why it’s failing, the documentation for add_custom_target says that add_dependencies() should be used instead of DEPENDS if you’re looking to add a dependency on another target, which looks to be your case with ros2cs_message_generator - not sure if that helps

3

Thanks a lot. Sometimes it’s hard to see the most obvious things. add_dependencies() has by the way the same problem as the DEPENDS statement.
I had to use this rather ugly solution:

 if(${PROJECT_NAME} STREQUAL "rosidl_generator_cs")
   add_dependencies(${MSG_TARGET_NAME} ros2cs_message_generator)
 endif()