I ran into an edge case today while working on a project that uses Drone.
If the entire pipeline is skipped because all conditions are false, drone still runs the build, only executing the clone stage, and then completes. It probably makes more sense for drone to skip the build entirely.
I was going to make a pull request to solve this issue, but the template advised me to post this here, first.
When 0.10 is released the build object will be created and stored in the database before the yaml is evaluated, so unfortunately we are moving in a direction where this would not be possible. This is in preparation for the introduction of the
.drone.js file . With that being said, we are introducing a new concept called triggers  which I believe can be used to eliminate this scenario.
 see http://discuss.harness.io/t/roadmap-for-the-1-0-release