Don't set BUNDLER_ORIG environment variables

bundler/lib/bundler.rb

@@ -34,9 +34,6 @@
 # of loaded and required modules.
 #
 module Bundler
-  environment_preserver = EnvironmentPreserver.from_env
-  ORIGINAL_ENV = environment_preserver.restore
-  environment_preserver.replace_with_backup
   SUDO_MUTEX = Thread::Mutex.new
 
   autoload :Definition,             File.expand_path("bundler/definition", __dir__)
@@ -78,6 +75,8 @@ module Bundler
   autoload :VersionRanges,          File.expand_path("bundler/version_ranges", __dir__)
 
   class << self
+    include EnvironmentPreserver
+
     def configure
       @configured ||= configure_gem_home_and_path
     end
@@ -344,11 +343,6 @@ def settings
       @settings = Settings.new(Pathname.new(".bundle").expand_path)
     end
 
-    # @return [Hash] Environment present before Bundler was activated
-    def original_env
-      ORIGINAL_ENV.clone
-    end
-
     # @deprecated Use `unbundled_env` instead
     def clean_env
       Bundler::SharedHelpers.major_deprecation(

bundler/lib/bundler/environment_preserver.rb

@@ -1,85 +1,19 @@
 # frozen_string_literal: true
 
 module Bundler
-  class EnvironmentPreserver
-    INTENTIONALLY_NIL = "BUNDLER_ENVIRONMENT_PRESERVER_INTENTIONALLY_NIL".freeze
-    BUNDLER_KEYS = %w[
-      BUNDLE_BIN_PATH
-      BUNDLE_GEMFILE
-      BUNDLER_VERSION
-      GEM_HOME
-      GEM_PATH
-      MANPATH
-      PATH
-      RB_USER_INSTALL
-      RUBYLIB
-      RUBYOPT
-    ].map(&:freeze).freeze
-    BUNDLER_PREFIX = "BUNDLER_ORIG_".freeze
-
-    def self.from_env
-      new(env_to_hash(ENV), BUNDLER_KEYS)
-    end
-
+  module EnvironmentPreserver
     def self.env_to_hash(env)
       to_hash = env.to_hash
       return to_hash unless Gem.win_platform?
 
       to_hash.each_with_object({}) {|(k,v), a| a[k.upcase] = v }
     end
 
-    # @param env [Hash]
-    # @param keys [Array<String>]
-    def initialize(env, keys)
-      @original = env
-      @keys = keys
-      @prefix = BUNDLER_PREFIX
-    end
-
-    # Replaces `ENV` with the bundler environment variables backed up
-    def replace_with_backup
-      unless Gem.win_platform?
-        ENV.replace(backup)
-        return
-      end
-
-      # Fallback logic for Windows below to workaround
-      # https://bugs.ruby-lang.org/issues/16798. Can be dropped once all
-      # supported rubies include the fix for that.
-
-      ENV.clear
-
-      backup.each {|k, v| ENV[k] = v }
-    end
-
-    # @return [Hash]
-    def backup
-      env = @original.clone
-      @keys.each do |key|
-        value = env[key]
-        if !value.nil? && !value.empty?
-          env[@prefix + key] ||= value
-        elsif value.nil?
-          env[@prefix + key] ||= INTENTIONALLY_NIL
-        end
-      end
-      env
-    end
+    ORIGINAL_ENV = env_to_hash(ENV)
 
-    # @return [Hash]
-    def restore
-      env = @original.clone
-      @keys.each do |key|
-        value_original = env[@prefix + key]
-        next if value_original.nil? || value_original.empty?
-        if value_original == INTENTIONALLY_NIL
-          env.delete(key)
-        else
-          env[key] = value_original
-        end
-        env.delete(@prefix + key)
-      end
-      env
+    # @return [Hash] Environment present before Bundler was activated
+    def original_env
+      ORIGINAL_ENV.clone
     end
   end
 end

bundler/lib/bundler/shared_helpers.rb

@@ -261,12 +261,6 @@ def search_up(*names)
     end
 
     def set_env(key, value)
-      raise ArgumentError, "new key #{key}" unless EnvironmentPreserver::BUNDLER_KEYS.include?(key)
-      orig_key = "#{EnvironmentPreserver::BUNDLER_PREFIX}#{key}"
-      orig = ENV[key]
-      orig ||= EnvironmentPreserver::INTENTIONALLY_NIL
-      ENV[orig_key] ||= orig
-
       ENV[key] = value
     end
     public :set_env

bundler/spec/runtime/with_unbundled_env_spec.rb

@@ -62,9 +62,6 @@ def run_bundler_script(env, script)
     end
 
     it "removes variables that bundler added", :ruby_repo do
-      # Simulate bundler has not yet been loaded
-      ENV.replace(ENV.to_hash.delete_if {|k, _v| k.start_with?(Bundler::EnvironmentPreserver::BUNDLER_PREFIX) })
-
       original = ruby('puts ENV.to_a.map {|e| e.join("=") }.sort.join("\n")')
       create_file("source.rb", <<-RUBY)
         puts Bundler.original_env.to_a.map {|e| e.join("=") }.sort.join("\n")