def populate_ds_graph!
      @all_artifacts = Set.new

      graph.artifacts.each do |artifact|
        add_artifact_to_ds_graph(artifact)
        @all_artifacts << ds_graph.package(artifact.name)
      end
    end
def populate_ds_graph!
      @all_artifacts = Set.new

      graph.artifacts.each do |artifact|
        add_artifact_to_ds_graph(artifact)
        @all_artifacts << ds_graph.package(artifact.name)
      end
    end
Converts artifacts to DepSelector::Package objects and adds them to the
 DepSelector graph. This should only be called once; use #all_artifacts
 to safely get the set of all artifacts.