class Bundler::Resolver

def amount_constrained(dependency)

before dependencies that are unconstrained
are given very negative values, so they _always_ sort first,
dependencies w/ 0 or 1 possibilities (ignoring version requirements)

a number closer to 0 means the dependency is less constraining
returns an integer \in (-\infty, 0] 
def amount_constrained(dependency)
  @amount_constrained ||= {}
  @amount_constrained[dependency.name] ||= begin
    if (base = @base[dependency.name]) && !base.empty?
      dependency.requirement.satisfied_by?(base.first.version) ? 0 : 1
    else
      all = index_for(dependency).search(dependency.name).size
      if all <= 1
        all - 1_000_000
      else
        search = search_for(dependency)
        search = @prerelease_specified[dependency.name] ? search.count : search.count {|s| !s.version.prerelease? }
        search - all
      end
    end
  end
end