class Gem::Resolver

def search_for(dependency)
  possibles, all = find_possible(dependency)
  if !@soft_missing && possibles.empty?
    exc = Gem::UnsatisfiableDependencyError.new dependency, all
    exc.errors = @set.errors
    raise exc
  end
  groups = Hash.new {|hash, key| hash[key] = [] }
  # create groups & sources in the same loop
  sources = possibles.map do |spec|
    source = spec.source
    groups[source] << spec
    source
  end.uniq.reverse
  activation_requests = []
  sources.each do |source|
    groups[source].
      sort_by {|spec| [spec.version, spec.platform =~ Gem::Platform.local ? 1 : 0] }. # rubocop:disable Performance/RegexpMatch
      map {|spec| ActivationRequest.new spec, dependency }.
      each {|activation_request| activation_requests << activation_request }
  end
  activation_requests
end