[rubygems/rubygems] Fix Bundler.original_env['GEM_HOME'] when Bundler is trampolined

ruby/rubygems@4c450eb05e

Author: deivid-rodriguez

lib/bundler/self_manager.rb

@@ -68,15 +68,23 @@ def install(spec)
 
     def restart_with(version)
       configured_gem_home = ENV["GEM_HOME"]
+      configured_orig_gem_home = ENV["BUNDLER_ORIG_GEM_HOME"]
       configured_gem_path = ENV["GEM_PATH"]
+      configured_orig_gem_path = ENV["BUNDLER_ORIG_GEM_PATH"]
 
       argv0 = File.exist?($PROGRAM_NAME) ? $PROGRAM_NAME : Process.argv0
       cmd = [argv0, *ARGV]
       cmd.unshift(Gem.ruby) unless File.executable?(argv0)
 
       Bundler.with_original_env do
         Kernel.exec(
-          { "GEM_HOME" => configured_gem_home, "GEM_PATH" => configured_gem_path, "BUNDLER_VERSION" => version.to_s },
+          {
+            "GEM_HOME" => configured_gem_home,
+            "BUNDLER_ORIG_GEM_HOME" => configured_orig_gem_home,
+            "GEM_PATH" => configured_gem_path,
+            "BUNDLER_ORIG_GEM_PATH" => configured_orig_gem_path,
+            "BUNDLER_VERSION" => version.to_s,
+          },
           *cmd
         )
       end

spec/bundler/runtime/self_management_spec.rb

@@ -82,6 +82,10 @@
       bundle "-v"
       expect(out).to eq(previous_minor)
 
+      # Preserves original gem home when auto-switching
+      bundle "exec ruby -e 'puts Bundler.original_env[\"GEM_HOME\"]'"
+      expect(out).to eq(ENV["GEM_HOME"])
+
       # ruby-core test setup has always "lib" in $LOAD_PATH so `require "bundler/setup"` always activate the local version rather than using RubyGems gem activation stuff
       unless ruby_core?
         # App now uses locked version, even when not using the CLI directly