Auto merge of #4268 - Elffers:hhh_fix_ruby-I, r=indirect

Place bundler loaded gems after -I and RUBYLIB

Previously, gems were being placed at the front of the LOAD_PATH. This
meant you couldn't override a gem by setting -I or RUBYLIB.

This patch places -I and RUBYLIB in front of loaded gems and matches the
behavior in RubyGems.

3 files changed, 42 insertions, 1 deletions

diff --git a/lib/bundler/rubygems_integration.rb b/lib/bundler/rubygems_integration.rb
index c8ebe2cb9a..0f567db12a 100644
--- a/lib/bundler/rubygems_integration.rb
+++ b/lib/bundler/rubygems_integration.rb
@@ -35,6 +35,10 @@ module Bundler
       Gem::Command.build_args = args
     end
 
+    def load_path_insert_index
+      Gem.load_path_insert_index
+    end
+
     def loaded_specs(name)
       Gem.loaded_specs[name]
     end
diff --git a/lib/bundler/runtime.rb b/lib/bundler/runtime.rb
index c2d5ad4b0a..e80a9eaeba 100644
--- a/lib/bundler/runtime.rb
+++ b/lib/bundler/runtime.rb
@@ -37,7 +37,17 @@ module Bundler
 
         Bundler.rubygems.mark_loaded(spec)
         load_paths = spec.load_paths.reject {|path| $LOAD_PATH.include?(path) }
-        $LOAD_PATH.unshift(*load_paths)
+
+        # See Gem::Specification#add_self_to_load_path (since RubyGems 1.8)
+        insert_index = Bundler.rubygems.load_path_insert_index
+
+        if insert_index
+          # Gem directories must come after -I and ENV['RUBYLIB']
+          $LOAD_PATH.insert(insert_index, *load_paths)
+        else
+          # We are probably testing in core, -I and RUBYLIB don't apply
+          $LOAD_PATH.unshift(*load_paths)
+        end
       end
 
       setup_manpath
diff --git a/spec/runtime/setup_spec.rb b/spec/runtime/setup_spec.rb
index be3d1baf2b..d6c60dcf24 100644
--- a/spec/runtime/setup_spec.rb
+++ b/spec/runtime/setup_spec.rb
@@ -108,6 +108,33 @@ describe "Bundler.setup" do
     end
   end
 
+  context "load order" do
+    it "puts loaded gems after -I and RUBYLIB" do
+      install_gemfile <<-G
+        source "file://#{gem_repo1}"
+        gem "rack"
+      G
+
+      ENV["RUBYOPT"] = "-Idash_i_dir"
+      ENV["RUBYLIB"] = "rubylib_dir"
+
+      ruby <<-RUBY
+        require 'rubygems'
+        require 'bundler'
+        Bundler.setup
+        puts $LOAD_PATH
+      RUBY
+
+      load_path = out.split("\n")
+      rack_load_order = load_path.index {|path| path.include?("rack") }
+
+      expect(err).to eq("")
+      expect(load_path[1]).to include "dash_i_dir"
+      expect(load_path[2]).to include "rubylib_dir"
+      expect(rack_load_order).to be > 0
+    end
+  end
+
   it "raises if the Gemfile was not yet installed" do
     gemfile <<-G
       source "file://#{gem_repo1}"