This PR most notably, - looks for ROS packages in `$SNAPCRAFT_PART_INSTALL/opt/ros/$ROS_DISTRO` in case the workspace exists (e.g. provided by a build-snap) during the build step - does not `rosdep resolve` packages that are available locally in `$SNAPCRAFT_PART_INSTALL/opt/ros/$ROS_DISTRO` during stage step. Such locally available package may be part of the built sources or provided by a stage-snap. Furthermore, it fixes the following current issue; if the source contains packages `foo` & `bar` - two packages that are not released in the rosdistro database - where `foo` depends on `bar`, staging fails as it tries to `rosdep resolve` the `bar` key (which does not exists since it is not released). With this fix, it finds `bar` locally and thus does not try to resolve it. - port 'test-snapcraft-fake-ros-package-core18' to core20 to test the above 2 bullets Note: - I own the test-snapcraft-fake-ros-package-core20 snap that's used in the new spread test, I imagine we should transfer ownership - [x] Have you followed the [guidelines for contributing](https://github.com/snapcore/snapcraft/blob/master/CONTRIBUTING.md)? - [x] Have you signed the [CLA](http://www.ubuntu.com/legal/contributors/)? - [x] Have you successfully run `./runtests.sh static`? - [x] Have you successfully run `./runtests.sh tests/unit`? -----