- [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] If this is a bugfix. Have you checked that there is a bug report open for the issue you are trying to fix on [bug reports](https://bugs.launchpad.net/snapcraft)? - [x] If this is a new feature. Have you discussed the design on the [forum](https://forum.snapcraft.io)? - [x] Have you successfully run `./runtests.sh static`? - [x] Have you successfully run `./runtests.sh unit`? ----- Currently, the Catkin plugin supports rosinstall files in that, if you hand it a list of rosinstall files in the source, it'll merge them into the workspace and fetch the repositories listed therein. However, what happens if _those_ repositories have rosinstall files of their own? This is not a situation wstool handles, and is something vendors script around. This PR resolves #1714 by adding explicit support in Snapcraft for this situation by way of a new boolean option: `recursive-rosinstall`. This option defaults to false (since that's typically how wstool behaves), but if it's true, it'll continue merging/updating the workspace with newly-fetched rosinstall files until no more are found.