Automatic eval fail in 4.9 quiz on pkg not found

Course Support ROS2 in 5 Days C++
1

The automatic evaluation fails on “package not found” in Quiz 4.9 (Ros2 in C++ 5days) even though both packages exist (“services_quiz” and “services_quiz_srv”) and can also launch just fine. This is also visible in the screenshot shown below where the packages are correctly found in the correct path also.
I have now tried three times recompiling the packages after cleaning using
rm -rf build/services_quiz install/services_quiz log/services_quiz

image
image1920×993 156 KB

2

Thank you for sharing that image! I can see some useful pointers therein.

  1. We have some strange files in ros2_ws/src, because you are inadvertently running colcon build in that directory. You need to run it in ros2_ws.
  2. You should be able to compile services_quiz and services_quiz_srv in one go, because services_quiz should depend on services_quiz_srv

Suggest way forward:

  1. Double-check that you have created and set up your packages properly, ensuring services_quiz has only one dependency within the workspace, services_quiz_srv, which must not depend on another package within the workspace.

  2. Remove strange files in ros2_ws/src and compile in ros2_ws. This step must pass without errors.

# Remove build files in src
cd ~/ros2_ws/src
rm -rf build/ install/ log/

# Recompile workspace
cd ~/ros2_ws
rm -rf build/ install/ log/
colcon build --packages-select services_quiz services_quiz_srv
source install/setup.bash
  1. Check that your packages exist and you can launch them properly. Then try to submit again.
3

Thanks it worked. I was missing a dependency in the package xml towards services_quiz_srv, so it worked when I manually build services_quiz_srv first, but not building at the same time. But I don’t understand what that had to do with th packages missing?
Btw. the quiz solution does not work either when pushing the button you get this:

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image1034×309 18.2 KB

4

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5

The packages are missing because they are not properly compiled. Only compiled packages are found by the ROS system.

Sorry about that. Let’s look into that.