Auto merge of #5837 - bundler:seg-default-gem-activation-spec-hack, r=segiddins

Improve logging in default gem activation specs

### What was the end-user problem that led to this PR?

The problem was those specs were failing on CI and I couldn't figure out why.

### What was your diagnosis of the problem?

My diagnosis was we needed the hack loaded before all bundler code.

### What is your fix for the problem, implemented in this PR?

My fix gets the hack loaded in via an `-r` switch set in `RUBYOPT`

### Why did you choose this fix out of the possible options?

I chose this fix because it will make spec failures more informative.

1 files changed, 14 insertions, 10 deletions

diff --git a/spec/runtime/setup_spec.rb b/spec/runtime/setup_spec.rb
index 3025b502ae..5e8d652497 100644
--- a/spec/runtime/setup_spec.rb
+++ b/spec/runtime/setup_spec.rb
@@ -1235,7 +1235,7 @@ end
         end << "bundler"
       end
 
-      let(:code) { strip_whitespace(<<-RUBY) }
+      let(:activation_warning_hack) { strip_whitespace(<<-RUBY) }
         require "rubygems"
 
         if Gem::Specification.instance_methods.map(&:to_sym).include?(:activate)
@@ -1250,7 +1250,14 @@ end
             bundler_spec_activate
           end
         end
+      RUBY
+
+      let(:activation_warning_hack_rubyopt) do
+        create_file("activation_warning_hack.rb", activation_warning_hack)
+        "-r#{bundled_app("activation_warning_hack.rb")} #{ENV["RUBYOPT"]}"
+      end
 
+      let(:code) { strip_whitespace(<<-RUBY) }
         require "bundler/setup"
         require "pp"
         loaded_specs = Gem.loaded_specs.dup
@@ -1266,17 +1273,15 @@ end
 
       it "activates no gems with -rbundler/setup" do
         install_gemfile! ""
-        ruby!(code)
-        expect(err).to eq("")
-        expect(out).to eq("{}")
+        ruby! code, :env => { :RUBYOPT => activation_warning_hack_rubyopt }
+        expect(last_command.stdout).to eq("{}")
       end
 
       it "activates no gems with bundle exec" do
         install_gemfile! ""
         create_file("script.rb", code)
-        bundle! "exec ruby ./script.rb"
-        expect(err).to eq("")
-        expect(out).to eq("{}")
+        bundle! "exec ruby ./script.rb", :env => { :RUBYOPT => activation_warning_hack_rubyopt }
+        expect(last_command.stdout).to eq("{}")
       end
 
       it "activates no gems with bundle exec that is loaded" do
@@ -1286,9 +1291,8 @@ end
         install_gemfile! ""
         create_file("script.rb", "#!/usr/bin/env ruby\n\n#{code}")
         FileUtils.chmod(0o777, bundled_app("script.rb"))
-        bundle! "exec ./script.rb", :artifice => nil
-        expect(err).to eq("")
-        expect(out).to eq("{}")
+        bundle! "exec ./script.rb", :artifice => nil, :env => { :RUBYOPT => activation_warning_hack_rubyopt }
+        expect(last_command.stdout).to eq("{}")
       end
 
       let(:default_gems) do