[rubygems/rubygems] Skip warnings if bundled gems is already loaded

https://github.com/rubygems/rubygems/commit/9583a7eb82

lib/bundler/rubygems_integration.rb

@@ -233,13 +233,15 @@ module Bundler
         kernel_class.send(:define_method, :require) do |file|
           name = file.tr("/", "-")
           if (::Gem::BUNDLED_GEMS.keys - specs.to_a.map(&:name)).include?(name)
-            target_file = begin
-                            Bundler.default_gemfile.basename
-                          rescue GemfileNotFound
-                            "inline Gemfile"
-                          end
-            warn "#{name} is not part of the default gems since Ruby #{::Gem::BUNDLED_GEMS[file]}." \
-            " Add it to your #{target_file}."
+            unless $LOADED_FEATURES.any?{|f| f.end_with?("#{name}.rb", "#{name}.#{RbConfig::CONFIG['DLEXT']}")}
+              target_file = begin
+                              Bundler.default_gemfile.basename
+                            rescue GemfileNotFound
+                              "inline Gemfile"
+                            end
+              warn "#{name} is not part of the default gems since Ruby #{::Gem::BUNDLED_GEMS[file]}." \
+              " Add it to your #{target_file}."
+            end
           end
           kernel_class.send(:no_warning_require, file)
         end

spec/bundler/runtime/setup_spec.rb

@@ -1574,6 +1574,25 @@ end
     expect(err).to include("csv is not part of the default gems")
   end
 
+  it "don't warn with bundled gems when it's loaded twice" do
+    build_repo4 do
+      build_gem "rack"
+    end
+
+    install_gemfile <<-G
+      source "#{file_uri_for(gem_repo4)}"
+      gem "rack"
+    G
+
+    ruby <<-R
+      require 'csv'
+      require 'bundler/setup'
+      require 'csv'
+    R
+
+    expect(err).to be_empty
+  end
+
   it "don't warn with bundled gems when it's declared in Gemfile" do
     build_repo4 do
       build_gem "csv"