2 files changed, 19 insertions, 0 deletions
diff --git a/lib/bundler/rubygems_integration.rb b/lib/bundler/rubygems_integration.rb
index 488aa8b9a4..ec1a408715 100644
--- a/lib/bundler/rubygems_integration.rb
+++ b/lib/bundler/rubygems_integration.rb
@@ -353,6 +353,10 @@ module Bundler
 
           true
         end
+
+        # TODO: delete this in 2.0, it's a backwards compatibility shim
+        # see https://github.com/bundler/bundler/issues/5102
+        kernel_class.send(:public, :gem)
       end
     end
 
diff --git a/spec/runtime/setup_spec.rb b/spec/runtime/setup_spec.rb
index eab66e2ee2..1251f25d80 100644
--- a/spec/runtime/setup_spec.rb
+++ b/spec/runtime/setup_spec.rb
@@ -1094,4 +1094,19 @@ describe "Bundler.setup" do
       expect(post_bundler).to match(/\d+\.\d+\.\d+/)
     end
   end
+
+  describe "after setup" do
+    it "allows calling #gem on random objects" do
+      install_gemfile <<-G
+        source "file:#{gem_repo1}"
+        gem "rack"
+      G
+      ruby! <<-RUBY
+        require "bundler/setup"
+        Object.new.gem "rack"
+        puts Gem.loaded_specs["rack"].full_name
+      RUBY
+      expect(out).to eq("rack-1.0.0")
+    end
+  end
 end