Adds a new {Edge} to the dependency graph @param [Vertex]
origin @param [Vertex]
destination @param [Object] requirement the
requirement that this edge represents @return [Edge] the added edge
# File lib/rubygems/resolver/molinillo/lib/molinillo/dependency_graph.rb, line 190
def add_edge(origin, destination, requirement)
if destination.path_to?(origin)
raise CircularDependencyError.new([origin, destination])
end
add_edge_no_circular(origin, destination, requirement)
end
