Core22 ROS 2 colcon snaps couldn't build packages creating custom ROS 2 interfaces. It was sourcing the environment before downloading the dependencies. Some dependencies (rosidl) have specificities when sourced, hence sourcing before downloading them causes issues. In the case of ROS 2 message, the PYTHONPATH only had the site-packages subdir and not the dist-packages subdir added by rosidl. This issue couldn't appear with lxd spread tests because the lxd environment was not cleaned properly by colcon spread tests (Debian packages were still installed, hence the dependencies were mostly already installed). Additionally, the advanced colcon spread tests had no entry in the spread.yaml and were never called. Hence, this code: - Adds missing spread entry for colcon specific tests - Adds package-utils.sh to restore the state of Debian package installed before a spread tests - Adds a colcon spread test with a message package to highlight that there is a bug - Fixes the bug by sourcing the ROS 2 environment after installing the ROS 2 dependencies - [ ] Have you followed the [guidelines for contributing](https://github.com/snapcore/snapcraft/blob/master/CONTRIBUTING.md)? - [ ] Have you signed the [CLA](http://www.ubuntu.com/legal/contributors/)? - [ ] Have you successfully run `make lint`? - [ ] Have you successfully run `pytest tests/unit`? -----