Use stub executables generated by RubyGems istead of original executables.

It resolved the conflict issues when invoking `gem i rdoc` and the binstub
issues with Bundler and Rails.

  [Bug #5060][ruby-core:38257][Fix GH-2023]

  * https://github.com/rubygems/rubygems/pull/2338
  * https://github.com/heroku/heroku-buildpack-ruby/issues/829

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65963 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 22 insertions, 6 deletions

diff --git a/bin/irb b/bin/irb
index c64ee85fbd..e44609a1b0 100755
--- a/bin/irb
+++ b/bin/irb
@@ -1,11 +1,27 @@
 #!/usr/bin/env ruby
 #
-#   irb.rb - interactive ruby
-#   	$Release Version: 0.9.6 $
-#   	$Revision$
-#   	by Keiju ISHITSUKA(keiju@ruby-lang.org)
+# This file was generated by RubyGems.
 #
+# The application 'irb' is installed as part of a gem, and
+# this file is here to facilitate running it.
+#
+
+require 'rubygems'
+
+version = ">= 0.a"
 
-require "irb"
+if ARGV.first
+  str = ARGV.first
+  str = str.dup.force_encoding("BINARY") if str.respond_to? :force_encoding
+  if str =~ /\A_(.*)_\z/ and Gem::Version.correct?($1) then
+    version = $1
+    ARGV.shift
+  end
+end
 
-IRB.start(__FILE__)
+if Gem.respond_to?(:activate_bin_path)
+load Gem.activate_bin_path('irb', 'irb', version)
+else
+gem "irb", version
+load Gem.bin_path("irb", "irb", version)
+end