Not obvious how to correctly build from source

[rotu]

Description

Fails to build with Ubuntu 18.04 and ROS source (i.e. master).

Note that all other platform/district pairs appear to build.

matrix:
  os: [ubuntu-18.04, macOS-latest, windows-latest]
  rosdistro: [dashing, eloquent, source]

https://github.com/RoverRobotics-forks/rmw_cyclonedds/pull/1/checks?check_run_id=544943756

Exit Criteria

• All inputs of the action are validated and properly throw an error if the input parameter is invalid
• Clarify the documentation to explain that by default, action-ros-ci is building from source because the default VCS file is containing all the ROS 2 repositories.

[thomas-moulard]

source is not a valid value for required-ros-distributions for action setup-ros.

There is a bug in the doc in https://github.com/ros-tooling/setup-ros/blob/master/action.yml
An empty string should be passed instead.

[rotu]

Thanks! That's exactly why I made this mistake. Here are some other suggestions which could help in addition to updating the docs:

1. required-ros-distributions doesn't really tell me that it's binaries. Maybe rename to 'binary-ros-distributions`.
2. I expect the failure message to mention that the provided value is invalid.
3. I expect the Mac OS and Windows to also fail if given an invalid distribution. I see that this argument is ignored silently on those platforms, but it should issue a warning or an error.

[jikawa-az]

Addressed in Validate that the distribution input is correct #196