fix #4149 by (again) waiting to load Psych

also add a new test specifically to catch if Psych is ever loaded by 
bundler/setup in the future

2 files changed, 16 insertions, 1 deletions

diff --git a/lib/bundler/rubygems_integration.rb b/lib/bundler/rubygems_integration.rb
index e5bd850743..f40b40b1de 100644
--- a/lib/bundler/rubygems_integration.rb
+++ b/lib/bundler/rubygems_integration.rb
@@ -1,7 +1,6 @@
 require "monitor"
 require "rubygems"
 require "rubygems/config_file"
-require "bundler/psyched_yaml"
 
 module Bundler
   class RubygemsIntegration
@@ -63,6 +62,7 @@ module Bundler
     end
 
     def configuration
+      require "bundler/psyched_yaml"
       Gem.configuration
     rescue Gem::SystemExitException => e
       Bundler.ui.error "#{e.class}: #{e.message}"
diff --git a/spec/runtime/setup_spec.rb b/spec/runtime/setup_spec.rb
index 4f0d395342..7e205ca59a 100644
--- a/spec/runtime/setup_spec.rb
+++ b/spec/runtime/setup_spec.rb
@@ -954,4 +954,19 @@ describe "Bundler.setup" do
       end
     end
   end
+
+  describe "when Psych is not in the Gemfile", :ruby => "~> 2.2" do
+    it "does not load Psych" do
+      gemfile ""
+      ruby <<-RUBY
+        require 'bundler/setup'
+        puts defined?(Psych::VERSION) ? Psych::VERSION : "undefined"
+        require 'psych'
+        puts Psych::VERSION
+      RUBY
+      pre_bundler, post_bundler = out.split("\n")
+      expect(pre_bundler).to eq("undefined")
+      expect(post_bundler).to match(/\d+\.\d+\.\d+/)
+    end
+  end
 end