fixup_swapped_children

# File lib/rubygems/resolver/molinillo/lib/molinillo/resolution.rb, line 359
      def fixup_swapped_children(vertex) # rubocop:disable Metrics/CyclomaticComplexity
        payload = vertex.payload
        deps = dependencies_for(payload).group_by(&method(:name_for))
        vertex.outgoing_edges.each do |outgoing_edge|
          requirement = outgoing_edge.requirement
          parent_index = @parents_of[requirement].last
          succ = outgoing_edge.destination
          matching_deps = Array(deps[succ.name])
          dep_matched = matching_deps.include?(requirement)

          # only push the current index when it was originally required by the
          # same named spec
          if parent_index && states[parent_index].name == name
            @parents_of[requirement].push(states.size - 1)
          end

          if matching_deps.empty? && !succ.root? && succ.predecessors.to_a == [vertex]
            debug(depth) { "Removing orphaned spec #{succ.name} after swapping #{name}" }
            succ.requirements.each { |r| @parents_of.delete(r) }

            removed_names = activated.detach_vertex_named(succ.name).map(&:name)
            requirements.delete_if do |r|
              # the only removed vertices are those with no other requirements,
              # so it's safe to delete only based upon name here
              removed_names.include?(name_for(r))
            end
          elsif !dep_matched
            debug(depth) { "Removing orphaned dependency #{requirement} after swapping #{name}" }
            # also reset if we're removing the edge, but only if its parent has
            # already been fixed up
            @parents_of[requirement].push(states.size - 1) if @parents_of[requirement].empty?

            activated.delete_edge(outgoing_edge)
            requirements.delete(requirement)
          end
        end
      end