Refactor bundled condition

Merged: https://github.com/ruby/ruby/pull/12847

lib/bundled_gems.rb

@@ -195,15 +195,17 @@ module Gem::BUNDLED_GEMS # :nodoc:
     Bundler.reset!
 
     builder = Bundler::Dsl.new
+
     if Bundler::SharedHelpers.in_bundle?
-      if Bundler.definition.gemfiles.empty?
+      if Bundler.locked_gems
         Bundler.locked_gems.specs.each{|spec| builder.gem spec.name, spec.version.to_s }
-      else
+      elsif Bundler.definition.gemfiles.size > 0
         Bundler.definition.gemfiles.each{|gemfile| builder.eval_gemfile(gemfile) }
       end
-      builder.gem gem
     end
 
+    builder.gem gem
+
     definition = builder.to_definition(nil, true)
     definition.validate_runtime!
 

spec/bundled_gems_spec.rb

@@ -363,11 +363,36 @@ RSpec.describe "bundled_gems.rb" do
   end
 
   describe ".force_activate" do
-    context "when gem activation fails" do
+    before do
+      allow_any_instance_of(Bundler::Runtime).to receive(:setup).and_raise(Bundler::GemNotFound)
+    end
+
+    context "with bundle environment" do
       before do
-        allow_any_instance_of(Bundler::Runtime).to receive(:setup).and_raise(Bundler::GemNotFound)
+        code = <<-RUBY
+          #!/usr/bin/env ruby
+
+          Gem::BUNDLED_GEMS.force_activate("csv")
+        RUBY
+        create_file("script.rb", code)
+        create_file("Gemfile", "source 'https://rubygems.org'")
       end
 
+      it "lockfile is available" do
+        bundle "install"
+        bundle "exec ./script.rb"
+
+        expect(err).to include("gem install csv")
+      end
+
+      it "lockfile is not available" do
+        bundle "exec ./script.rb"
+
+        expect(err).to include("gem install csv")
+      end
+    end
+
+    context "without bundle environment" do
       it "warns about installation requirement" do
         expect_any_instance_of(Object).to receive(:warn)
         Gem::BUNDLED_GEMS.force_activate("csv")