From: Stephen Bannasch <stephen.bannasch@...>
Date: 2010-08-29T23:53:05+09:00
Subject: [ruby-core:31928] Re: Avoiding $LOAD_PATH pollution

At 2:01 PM +0900 8/29/10, Eric Hodel wrote:
>On Aug 28, 2010, at 23:45, Run Paint Run Run wrote:
>>
>>>> How confident are we that this API would be sufficient for replacing the
>>>> multiude of require hacks present in the various RubyGems replacements?
>>
>>> I know of no successful RubyGems replacement that alters Kernel#require
>>> (rvm, bundler, isolate depend on RubyGems, RubyOpals never got off the
>>> ground, RPA is long dead).
>>
>> Ah, OK. I thought I'd read about various libraries overriding `require`, and
>> chaos resulting, but I can't find the thread again, so was possibly
>> hallucinating.
>
>Yes, I recall this thread... I don't know of any wide-spread use of the idea besides RubyGems.  I think it was a theoretical discussion.
>
>> Theoretically, the presence of arbitrary objects in $LOAD_PATH breaks backward
>> compatibility in that users may expect an Array of Strings. That's not a
>> significant hurdle, however.
>
>Yes.
>
>How often do people use $LOAD_PATH besides printing it?

Scanning through a local dir with many gems most of the uses are adding to $LOAD_PATH using '<<', 'unshift', 'shift',and 'push'

Scanning through these gems:
  aasm, activerecord-import, activerecord-jdbc-adapter, arel,
  aruba, awesome_print, awestruct, bj, bones, buildr, bundler,
  chef, cloud-crowd, compass, composite_primary_keys, couch_foo,
  cucumber, datamapper, desert, docrails, dropbox, earth,
  em-http-request, execwar, extlib, fakeweb, ffi-zlib, gem-this,
  gherkin, gist, git_remote_branch, goio, goio-ffi, haml,
  has_many_polymorphs, jammit, jasmine-gem, jeweler, journeta,
  libxml, mail, merb, mixlib-cli, mongrel, neo4j, nokogiri, ohm,
  passenger, persevere, prawn, prawn-format, rack, rack-fiber_pool,
  rack-reverse-proxy, radiant, railroad, rails, rainbows, rake,
  rake-compiler, rawr, rcov, rdoc, redcar, ri_cal, rjack, rspec,
  rspec-core, rspec-rails, ruby-debug, ruby-debug-ide, showoff,
  sinatra, sinatra_more, specjour, spork, sqlite3-ruby-1.2.4,
  strokedb, test23, threadz, treetop, ttfunk, ultraviolet, warbler,
  webrat, words, yajl-ruby, yard

Here's the interactions with $LOAD_PATH that don't involve adding to it using: '<<', 'unshift', 'shift', 'concat' and 'push' or directly printing it:

  $LOAD_PATH.clear
  $LOAD_PATH.delete File.expand_path('../unregistered_handler', __FILE__)
  $LOAD_PATH.delete(@other_load_path)
  $LOAD_PATH.delete(@path)
  $LOAD_PATH.each do |base|
  $LOAD_PATH.each do |path|
  $LOAD_PATH.include?(File.expand_path(__DIR__))
  $LOAD_PATH.include?(__DIR__) ||
  $LOAD_PATH.index(File.join(RAILS_ROOT, 'lib')) || 0
  $LOAD_PATH.insert(application_lib_index + 1, path)
  $LOAD_PATH.reject! do |p|
  $LOAD_PATH.reject! { |path| !(original_load_path.include?(path)) }
  $LOAD_PATH.replace @_sandbox[:load_path]
  $LOAD_PATH.should include(libdir)
  $LOAD_PATH.should include(specdir)
  $LOAD_PATH.should_receive(:unshift).with("a/dir")
  $LOAD_PATH.stub!(:unshift)
  $LOAD_PATH.uniq!
  !$LOAD_PATH.include?(component_path)
  $servlet_context.log("LoadError while loading '#{library}', current path:\n " + $LOAD_PATH.join("\n "))
  %w{test lib ext/libxml}.each{ |path| $LOAD_PATH.unshift(path) }
  @options[:load_paths].each {|p| $LOAD_PATH << p}
  @snoop[:load_path]         = $LOAD_PATH
  @snoop[:load_path] = $LOAD_PATH
  @_sandbox[:load_path] = $LOAD_PATH.clone
  abs = $LOAD_PATH.map { |path| ::File.join(path, loaded) }.
  ar_lib_path = $LOAD_PATH.detect {|p| p if File.exist?File.join(p, ar_version)}
  assert $LOAD_PATH.include?(File.join(plugin_fixture_path('default/acts/acts_as_chunky_bacon'), 'lib'))
  assert $LOAD_PATH.include?(File.join(plugin_fixture_path('default/stubby'), 'lib'))
  assert $LOAD_PATH.index(File.join(plugin_fixture_path('default/acts/acts_as_chunky_bacon'), 'lib')) >= assert  
    $LOAD_PATH.index(File.join(plugin_fixture_path('default/stubby'), 'lib')) >= stubbed_application_lib_index_in_LOAD_PATHS
  assert load_paths_count.select { |k, v| v > 1 }.empty?, $LOAD_PATH.inspect
  def add_dir_from_project_root_to_load_path(dir, load_path=$LOAD_PATH) # :nodoc:
  def rake_require(file_name, paths=$LOAD_PATH, loaded=$")
  describe $LOAD_PATH do
  dir  = $LOAD_PATH.find { |dir| File.exist? File.join(dir, file) }
  env["test.$LOAD_PATH"]  = $LOAD_PATH
  f << "$LOAD_PATH.unshift 'file:' + dir + '/#{rack_dir}'\n"
  f << "$LOAD_PATH.unshift dir + '/#{rack_dir}'\n"
  files = $LOAD_PATH.map do |p|
  if $LOAD_PATH.first != LIBDIR
  if ( $LOAD_PATH.index( ext_dir ).nil? )
  it "should prepend gemspec require paths to $LOAD_PATH in order" do
  libs.map {|lib| $LOAD_PATH.unshift lib}
  libs.reverse.each{|lib| $LOAD_PATH.unshift(lib)}
  load_paths = spec.load_paths.reject {|path| $LOAD_PATH.include?(path)}
  load_paths.reverse_each { |dir| $LOAD_PATH.unshift(dir) if File.directory?(dir) }
  load_paths_count = $LOAD_PATH.inject({}) { |paths, path|
  on("--dev", "Add this project's bin/ and lib/ to $LOAD_PATH.",
  on("-I PATH", "Add PATH to $LOAD_PATH") do |path|
  opts.on("-I", "--include PATH", String, "Add PATH to $LOAD_PATH") do |path|
  opts.on('-I', '--include PATH', String, 'Add PATH to $LOAD_PATH') do |path|
  original_load_path = $LOAD_PATH
  ORIGINAL_LOAD_PATH = $LOAD_PATH.dup
  ORIGINAL_LOAD_PATH.each { |path| $LOAD_PATH << path }
  parser.on('-I DIRECTORY', 'specify $LOAD_PATH directory (may be used more than once)') do |dir|
  path = $LOAD_PATH.grep(/#{gem_name}[\w.-]*\/lib$/).first
  paths = ['./', *$LOAD_PATH].uniq
  plugin.load_paths.each { |path| $LOAD_PATH.unshift(path) }
  plugin_load_paths.each { |path| assert $LOAD_PATH.include?(path) }
  puts $LOAD_PATH.grep(/activesupport/i)
  puts( $LOAD_PATH.inject([]) do |res, path|
  require spec_classes_path unless $LOAD_PATH.include?(spec_classes_path)
  template_dir = $LOAD_PATH.map do |path|