Stop cleaning up $LOAD_PATH on bundler/setup

If the `$LOAD_PATH` has been modified prior to bundler being loaded,
don't mess with that, just put the paths of the gems resolved by the
Gemfile{,.lock} file in front of it.

This way, if some default gem has been required before bundler, and
rubygems has enhanced the `$LOAD_PATH` to use the latest version in the
system, further requires of that default gem after bundler has been
activated will use the same version. That, unless the gem is a Gemfile
dependency. In that case, we'll get a mismatch error anyways as we do
now.

Author: deivid-rodriguez

bundler/lib/bundler.rb

@@ -149,6 +149,7 @@ def setup(*groups)
         # Load all groups, but only once
         @setup = load.setup
       else
+        SharedHelpers.clean_load_path
         load.setup(*groups)
       end
     end

bundler/lib/bundler/runtime.rb

@@ -12,9 +12,6 @@ def initialize(root, definition)
     def setup(*groups)
       @definition.ensure_equivalent_gemfile_and_lockfile if Bundler.frozen_bundle?
 
-      # Has to happen first
-      clean_load_path
-
       specs = @definition.specs_for(groups)
 
       SharedHelpers.set_bundle_environment

bundler/lib/bundler/shared_helpers.rb

@@ -198,6 +198,18 @@ def write_to_gemfile(gemfile_path, contents)
       filesystem_access(gemfile_path) {|g| File.open(g, "w") {|file| file.puts contents } }
     end
 
+    def clean_load_path
+      bundler_lib = bundler_ruby_lib
+
+      loaded_gem_paths = Bundler.rubygems.loaded_gem_paths
+
+      $LOAD_PATH.reject! do |p|
+        next if resolve_path(p).start_with?(bundler_lib)
+        loaded_gem_paths.delete(p)
+      end
+      $LOAD_PATH.uniq!
+    end
+
     private
 
     def validate_bundle_path
@@ -312,18 +324,6 @@ def bundler_ruby_lib
       resolve_path File.expand_path("../..", __FILE__)
     end
 
-    def clean_load_path
-      bundler_lib = bundler_ruby_lib
-
-      loaded_gem_paths = Bundler.rubygems.loaded_gem_paths
-
-      $LOAD_PATH.reject! do |p|
-        next if resolve_path(p).start_with?(bundler_lib)
-        loaded_gem_paths.delete(p)
-      end
-      $LOAD_PATH.uniq!
-    end
-
     def resolve_path(path)
       expanded = File.expand_path(path)
       return expanded unless File.respond_to?(:realpath) && File.exist?(expanded)

bundler/spec/runtime/setup_spec.rb

@@ -828,37 +828,6 @@ def clean_load_path(lp)
     expect(out).to eq("yay")
   end
 
-  it "should clean $LOAD_PATH properly", :ruby_repo do
-    gem_name = "very_simple_binary"
-    full_gem_name = gem_name + "-1.0"
-    ext_dir = File.join(tmp("extensions", full_gem_name))
-
-    system_gems full_gem_name
-
-    install_gemfile <<-G
-      source "#{file_uri_for(gem_repo1)}"
-    G
-
-    ruby <<-R
-      s = Gem::Specification.find_by_name '#{gem_name}'
-      s.extension_dir = '#{ext_dir}'
-
-      # Don't build extensions.
-      s.class.send(:define_method, :build_extensions) { nil }
-
-      require 'bundler'
-      gem '#{gem_name}'
-
-      puts $LOAD_PATH.count {|path| path =~ /#{gem_name}/} >= 2
-
-      Bundler.setup
-
-      puts $LOAD_PATH.count {|path| path =~ /#{gem_name}/} == 0
-    R
-
-    expect(out).to eq("true\ntrue")
-  end
-
   context "with bundler is located in symlinked GEM_HOME" do
     let(:gem_home) { Dir.mktmpdir }
     let(:symlinked_gem_home) { Tempfile.new("gem_home").path }
@@ -1511,5 +1480,28 @@ def lock_with(ruby_version = nil)
 
       expect(out).to include("rack, yard")
     end
+
+    it "does not cause double loads when higher versions of default gems are activated before bundler" do
+      build_repo2 do
+        build_gem "json", "999.999.999" do |s|
+          s.write "lib/json.rb", <<~RUBY
+            module JSON
+              VERSION = "999.999.999"
+            end
+          RUBY
+        end
+      end
+
+      system_gems "json-999.999.999", :gem_repo => gem_repo2
+
+      install_gemfile "source \"#{file_uri_for(gem_repo1)}\""
+      ruby <<-RUBY
+        require "json"
+        require "bundler/setup"
+        require "json"
+      RUBY
+
+      expect(err).to be_empty
+    end
   end
 end