diff --git a/lib/bundler/cli.rb b/lib/bundler/cli.rb
index 3d93ce5e6f..e1c284130b 100644
--- a/lib/bundler/cli.rb
+++ b/lib/bundler/cli.rb
@@ -251,7 +251,9 @@ module Bundler
       remembered_negative_flag_deprecation("no-deployment")
 
       require_relative "cli/install"
-      Install.new(options.dup).run
+      Bundler.settings.temporary(:no_install => false) do
+        Install.new(options.dup).run
+      end
     end
 
     map aliases_for("install")
@@ -297,7 +299,9 @@ module Bundler
     def update(*gems)
       SharedHelpers.major_deprecation(2, "The `--force` option has been renamed to `--redownload`") if ARGV.include?("--force")
       require_relative "cli/update"
-      Update.new(options, gems).run
+      Bundler.settings.temporary(:no_install => false) do
+        Update.new(options, gems).run
+      end
     end
 
     desc "show GEM [OPTIONS]", "Shows all gems that are part of the bundle, or the path to a given gem"
diff --git a/lib/bundler/cli/cache.rb b/lib/bundler/cli/cache.rb
index eb5dd23092..c8698ed7e3 100644
--- a/lib/bundler/cli/cache.rb
+++ b/lib/bundler/cli/cache.rb
@@ -14,7 +14,7 @@ module Bundler
       Bundler.settings.set_command_option_if_given :cache_path, options["cache-path"]
 
       setup_cache_all
-      install unless Bundler.settings[:no_install]
+      install
 
       # TODO: move cache contents here now that all bundles are locked
       custom_path = Bundler.settings[:path] if options[:path]
diff --git a/lib/bundler/cli/install.rb b/lib/bundler/cli/install.rb
index acf92f28ad..e9b85f7f6f 100644
--- a/lib/bundler/cli/install.rb
+++ b/lib/bundler/cli/install.rb
@@ -161,6 +161,8 @@ module Bundler
 
       Bundler.settings.set_command_option_if_given :no_prune, options["no-prune"]
 
+      Bundler.settings.set_command_option_if_given :no_install, options["no-install"]
+
       Bundler.settings.set_command_option_if_given :clean, options["clean"]
 
       normalize_groups if options[:without] || options[:with]
diff --git a/lib/bundler/current_ruby.rb b/lib/bundler/current_ruby.rb
index 27997982c0..36f26b7ab4 100644
--- a/lib/bundler/current_ruby.rb
+++ b/lib/bundler/current_ruby.rb
@@ -78,7 +78,7 @@ module Bundler
     end
 
     def x64_mingw?
-      Gem.win_platform? && Bundler.local_platform != Gem::Platform::RUBY && Bundler.local_platform.os == "mingw32" && Bundler.local_platform.cpu == "x64"
+      Gem.win_platform? && Bundler.local_platform != Gem::Platform::RUBY && Bundler.local_platform.os.start_with?("mingw") && Bundler.local_platform.cpu == "x64"
     end
 
     (KNOWN_MINOR_VERSIONS + KNOWN_MAJOR_VERSIONS).each do |version|
diff --git a/lib/bundler/dependency.rb b/lib/bundler/dependency.rb
index 018a3182b9..472363c72c 100644
--- a/lib/bundler/dependency.rb
+++ b/lib/bundler/dependency.rb
@@ -122,7 +122,7 @@ module Bundler
     end
 
     def expanded_platforms
-      @expanded_platforms ||= @platforms.map {|pl| PLATFORM_MAP[pl] }.compact.uniq
+      @expanded_platforms ||= @platforms.map {|pl| PLATFORM_MAP[pl] }.compact.flatten.uniq
     end
 
     def should_include?
diff --git a/lib/bundler/friendly_errors.rb b/lib/bundler/friendly_errors.rb
index ff6cdc4123..d0d2a6679a 100644
--- a/lib/bundler/friendly_errors.rb
+++ b/lib/bundler/friendly_errors.rb
@@ -29,8 +29,11 @@ module Bundler
         Bundler.ui.error error.message
         Bundler.ui.trace error.orig_exception
       when BundlerError
-        Bundler.ui.error error.message, :wrap => true
-        Bundler.ui.trace error
+        if Bundler.ui.debug?
+          Bundler.ui.trace error
+        else
+          Bundler.ui.error error.message, :wrap => true
+        end
       when Thor::Error
         Bundler.ui.error error.message
       when LoadError
diff --git a/lib/bundler/gem_helpers.rb b/lib/bundler/gem_helpers.rb
index 632698482f..d85d23f0db 100644
--- a/lib/bundler/gem_helpers.rb
+++ b/lib/bundler/gem_helpers.rb
@@ -10,6 +10,7 @@ module Bundler
       [Gem::Platform.new("universal-mingw32"), Gem::Platform.new("universal-mingw32")],
       [Gem::Platform.new("x64-mingw32"), Gem::Platform.new("x64-mingw32")],
       [Gem::Platform.new("x86_64-mingw32"), Gem::Platform.new("x64-mingw32")],
+      [Gem::Platform.new("x64-mingw-ucrt"), Gem::Platform.new("x64-mingw-ucrt")],
       [Gem::Platform.new("mingw32"), Gem::Platform.new("x86-mingw32")],
     ].freeze
 
diff --git a/lib/bundler/index.rb b/lib/bundler/index.rb
index 8930fca6d0..5bc24fc0b2 100644
--- a/lib/bundler/index.rb
+++ b/lib/bundler/index.rb
@@ -192,11 +192,7 @@ module Bundler
         specs += base if base
         found = specs.select do |spec|
           next true if spec.source.is_a?(Source::Gemspec)
-          if base # allow all platforms when searching from a lockfile
-            dependency.matches_spec?(spec)
-          else
-            dependency.matches_spec?(spec) && Gem::Platform.match_spec?(spec)
-          end
+          dependency.matches_spec?(spec)
         end
 
         found
diff --git a/lib/bundler/installer/standalone.rb b/lib/bundler/installer/standalone.rb
index e8494b4bcd..248b677233 100644
--- a/lib/bundler/installer/standalone.rb
+++ b/lib/bundler/installer/standalone.rb
@@ -12,6 +12,7 @@ module Bundler
       end
       File.open File.join(bundler_path, "setup.rb"), "w" do |file|
         file.puts "require 'rbconfig'"
+        file.puts define_path_helpers
         file.puts reverse_rubygems_kernel_mixin
         paths.each do |path|
           if Pathname.new(path).absolute?
@@ -29,14 +30,20 @@ module Bundler
       @specs.map do |spec|
         next if spec.name == "bundler"
         Array(spec.require_paths).map do |path|
-          gem_path(path, spec).sub(version_dir, '#{RUBY_ENGINE}/#{RbConfig::CONFIG["ruby_version"]}')
+          gem_path(path, spec).
+            sub(version_dir, '#{RUBY_ENGINE}/#{Gem.ruby_api_version}').
+            sub(extensions_dir, 'extensions/\k<platform>/#{Gem.extension_api_version}')
           # This is a static string intentionally. It's interpolated at a later time.
         end
       end.flatten.compact
     end
 
     def version_dir
-      "#{RUBY_ENGINE}/#{RbConfig::CONFIG["ruby_version"]}"
+      "#{RUBY_ENGINE}/#{Gem.ruby_api_version}"
+    end
+
+    def extensions_dir
+      %r{extensions/(?<platform>[^/]+)/#{Regexp.escape(Gem.extension_api_version)}}
     end
 
     def bundler_path
@@ -55,6 +62,26 @@ module Bundler
       raise Gem::InvalidSpecificationException.new(error_message)
     end
 
+    def define_path_helpers
+      <<~'END'
+        unless defined?(Gem)
+          module Gem
+            def self.ruby_api_version
+              RbConfig::CONFIG["ruby_version"]
+            end
+
+            def self.extension_api_version
+              if 'no' == RbConfig::CONFIG['ENABLE_SHARED']
+                "#{ruby_api_version}-static"
+              else
+                ruby_api_version
+              end
+            end
+          end
+        end
+      END
+    end
+
     def reverse_rubygems_kernel_mixin
       <<~END
       kernel = (class << ::Kernel; self; end)
diff --git a/lib/bundler/lazy_specification.rb b/lib/bundler/lazy_specification.rb
index 198906b987..8430b86988 100644
--- a/lib/bundler/lazy_specification.rb
+++ b/lib/bundler/lazy_specification.rb
@@ -84,7 +84,7 @@ module Bundler
         else
           ruby_platform_materializes_to_ruby_platform? ? self : Dependency.new(name, version)
         end
-        platform_object = Gem::Platform.new(platform)
+        platform_object = ruby_platform_materializes_to_ruby_platform? ? Gem::Platform.new(platform) : Gem::Platform.local
         candidates = source.specs.search(search_object)
         same_platform_candidates = candidates.select do |spec|
           MatchPlatform.platforms_match?(spec.platform, platform_object)
@@ -152,7 +152,7 @@ module Bundler
     # explicitly add a more specific platform.
     #
     def ruby_platform_materializes_to_ruby_platform?
-      !Bundler.most_specific_locked_platform?(Gem::Platform::RUBY) || Bundler.settings[:force_ruby_platform]
+      !Bundler.most_specific_locked_platform?(generic_local_platform) || Bundler.settings[:force_ruby_platform]
     end
   end
 end
diff --git a/lib/bundler/man/bundle-add.1 b/lib/bundler/man/bundle-add.1
index 5ed5cf6f68..821c253ff2 100644
--- a/lib/bundler/man/bundle-add.1
+++ b/lib/bundler/man/bundle-add.1
@@ -41,7 +41,7 @@ Specify version requirements(s) for the added gem\.
 Specify the group(s) for the added gem\. Multiple groups should be separated by commas\.
 .
 .TP
-\fB\-\-source\fR, , \fB\-s\fR
+\fB\-\-source\fR, \fB\-s\fR
 Specify the source for the added gem\.
 .
 .TP
diff --git a/lib/bundler/man/bundle-add.1.ronn b/lib/bundler/man/bundle-add.1.ronn
index 7571a431ab..8eead9c569 100644
--- a/lib/bundler/man/bundle-add.1.ronn
+++ b/lib/bundler/man/bundle-add.1.ronn
@@ -27,7 +27,7 @@ bundle add rails --group "development, test"
 * `--group`, `-g`:
   Specify the group(s) for the added gem. Multiple groups should be separated by commas.
 
-* `--source`, , `-s`:
+* `--source`, `-s`:
   Specify the source for the added gem.
 
 * `--require`, `-r`:
diff --git a/lib/bundler/match_platform.rb b/lib/bundler/match_platform.rb
index 69074925a6..7f7e8227f9 100644
--- a/lib/bundler/match_platform.rb
+++ b/lib/bundler/match_platform.rb
@@ -15,7 +15,6 @@ module Bundler
       return true if Gem::Platform::RUBY == gemspec_platform
       return true if local_platform == gemspec_platform
       gemspec_platform = Gem::Platform.new(gemspec_platform)
-      return true if GemHelpers.generic(gemspec_platform) === local_platform
       return true if gemspec_platform === local_platform
 
       false
diff --git a/lib/bundler/resolver.rb b/lib/bundler/resolver.rb
index 18eb18160d..fc4d7cb15d 100644
--- a/lib/bundler/resolver.rb
+++ b/lib/bundler/resolver.rb
@@ -284,7 +284,7 @@ module Bundler
       if specs_matching_requirement.any?
         specs = specs_matching_requirement
         matching_part = requirement_label
-        requirement_label = "#{requirement_label} #{requirement.__platform}"
+        requirement_label = "#{requirement_label}' with platform '#{requirement.__platform}"
       end
 
       message = String.new("Could not find gem '#{requirement_label}'#{extra_message} in #{source}#{cache_message}.\n")
diff --git a/lib/bundler/rubygems_ext.rb b/lib/bundler/rubygems_ext.rb
index af669d7d0b..a47692d1f2 100644
--- a/lib/bundler/rubygems_ext.rb
+++ b/lib/bundler/rubygems_ext.rb
@@ -216,11 +216,12 @@ module Gem
   require "rubygems/platform"
 
   class Platform
-    JAVA  = Gem::Platform.new("java") unless defined?(JAVA)
-    MSWIN = Gem::Platform.new("mswin32") unless defined?(MSWIN)
-    MSWIN64 = Gem::Platform.new("mswin64") unless defined?(MSWIN64)
-    MINGW = Gem::Platform.new("x86-mingw32") unless defined?(MINGW)
-    X64_MINGW = Gem::Platform.new("x64-mingw32") unless defined?(X64_MINGW)
+    JAVA  = Gem::Platform.new("java")
+    MSWIN = Gem::Platform.new("mswin32")
+    MSWIN64 = Gem::Platform.new("mswin64")
+    MINGW = Gem::Platform.new("x86-mingw32")
+    X64_MINGW = [Gem::Platform.new("x64-mingw32"),
+                 Gem::Platform.new("x64-mingw-ucrt")].freeze
   end
 
   Platform.singleton_class.module_eval do
diff --git a/lib/bundler/source/rubygems.rb b/lib/bundler/source/rubygems.rb
index f78e6a443b..04ba4a654c 100644
--- a/lib/bundler/source/rubygems.rb
+++ b/lib/bundler/source/rubygems.rb
@@ -160,6 +160,8 @@ module Bundler
           raise GemNotFound, "Could not find #{spec.file_name} for installation" unless path
         end
 
+        return if Bundler.settings[:no_install]
+
         if requires_sudo?
           install_path = Bundler.tmp(spec.full_name)
           bin_path     = install_path.join("bin")
diff --git a/lib/bundler/spec_set.rb b/lib/bundler/spec_set.rb
index 0dfaed9807..2df14fbb09 100644
--- a/lib/bundler/spec_set.rb
+++ b/lib/bundler/spec_set.rb
@@ -12,17 +12,19 @@ module Bundler
     end
 
     def for(dependencies, check = false, match_current_platform = false)
-      handled = []
+      # dep.name => [list, of, deps]
+      handled = Hash.new {|h, k| h[k] = [] }
       deps = dependencies.dup
       specs = []
 
       loop do
         break unless dep = deps.shift
-        next if handled.any? {|d| d.name == dep.name && (match_current_platform || d.__platform == dep.__platform) } || dep.name == "bundler"
+        next if handled[dep.name].any? {|d| match_current_platform || d.__platform == dep.__platform } || dep.name == "bundler"
 
-        handled << dep
+        # use a hash here to ensure constant lookup time in the `any?` call above
+        handled[dep.name] << dep
 
-        specs_for_dep = spec_for_dependency(dep, match_current_platform)
+        specs_for_dep = specs_for_dependency(dep, match_current_platform)
         if specs_for_dep.any?
           specs.concat(specs_for_dep)
 
@@ -171,12 +173,13 @@ module Bundler
       @specs.sort_by(&:name).each {|s| yield s }
     end
 
-    def spec_for_dependency(dep, match_current_platform)
-      specs_for_platforms = lookup[dep.name]
+    def specs_for_dependency(dep, match_current_platform)
+      specs_for_name = lookup[dep.name]
       if match_current_platform
-        GemHelpers.select_best_platform_match(specs_for_platforms.select {|s| Gem::Platform.match_spec?(s) }, Bundler.local_platform)
+        GemHelpers.select_best_platform_match(specs_for_name.select {|s| Gem::Platform.match_spec?(s) }, Bundler.local_platform)
       else
-        GemHelpers.select_best_platform_match(specs_for_platforms, dep.__platform)
+        specs_for_name_and_platform = GemHelpers.select_best_platform_match(specs_for_name, dep.__platform)
+        specs_for_name_and_platform.any? ? specs_for_name_and_platform : specs_for_name
       end
     end
 
diff --git a/lib/bundler/version.rb b/lib/bundler/version.rb
index a9a2934be8..efb0162ea3 100644
--- a/lib/bundler/version.rb
+++ b/lib/bundler/version.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: false
 
 module Bundler
-  VERSION = "2.3.16".freeze
+  VERSION = "2.3.17".freeze
 
   def self.bundler_major_version
     @bundler_major_version ||= VERSION.split(".").first.to_i
diff --git a/lib/rubygems.rb b/lib/rubygems.rb
index 1dd8e27486..00169ba587 100644
--- a/lib/rubygems.rb
+++ b/lib/rubygems.rb
@@ -8,7 +8,7 @@
 require 'rbconfig'
 
 module Gem
-  VERSION = "3.3.16".freeze
+  VERSION = "3.3.17".freeze
 end
 
 # Must be first since it unloads the prelude from 1.9.2
@@ -1323,8 +1323,9 @@ begin
 rescue LoadError
   # Ignored
 rescue StandardError => e
+  path = e.backtrace_locations.reverse.find {|l| l.path.end_with?("rubygems/defaults/operating_system.rb") }.path
   msg = "#{e.message}\n" \
-    "Loading the rubygems/defaults/operating_system.rb file caused an error. " \
+    "Loading the #{path} file caused an error. " \
     "This file is owned by your OS, not by rubygems upstream. " \
     "Please find out which OS package this file belongs to and follow the guidelines from your OS to report " \
     "the problem and ask for help."
diff --git a/lib/rubygems/commands/environment_command.rb b/lib/rubygems/commands/environment_command.rb
index b6eeb620bd..b6b3d3812c 100644
--- a/lib/rubygems/commands/environment_command.rb
+++ b/lib/rubygems/commands/environment_command.rb
@@ -8,8 +8,9 @@ class Gem::Commands::EnvironmentCommand < Gem::Command
 
   def arguments # :nodoc:
     args = <<-EOF
-          gemdir          display the path where gems are installed
-          gempath         display path used to search for gems
+          home            display the path where gems are installed. Aliases: gemhome, gemdir, GEM_HOME
+          path            display path used to search for gems. Aliases: gempath, GEM_PATH
+          user_gemhome    display the path where gems are installed when `--user-install` is given. Aliases: user_gemdir
           version         display the gem format version
           remotesources   display the remote gem servers
           platform        display the supported gem platforms
@@ -80,6 +81,8 @@ lib/rubygems/defaults/operating_system.rb
         Gem.dir
       when /^gempath/, /^path/, /^GEM_PATH/ then
         Gem.path.join(File::PATH_SEPARATOR)
+      when /^user_gemdir/, /^user_gemhome/ then
+        Gem.user_dir
       when /^remotesources/ then
         Gem.sources.to_a.join("\n")
       when /^platform/ then
diff --git a/lib/rubygems/ext/builder.rb b/lib/rubygems/ext/builder.rb
index e9986a3fc8..99dd2c162c 100644
--- a/lib/rubygems/ext/builder.rb
+++ b/lib/rubygems/ext/builder.rb
@@ -17,7 +17,7 @@ class Gem::Ext::Builder
     $1.downcase
   end
 
-  def self.make(dest_path, results, make_dir = Dir.pwd)
+  def self.make(dest_path, results, make_dir = Dir.pwd, sitedir = nil)
     unless File.exist? File.join(make_dir, 'Makefile')
       raise Gem::InstallError, 'Makefile not found'
     end
@@ -33,11 +33,18 @@ class Gem::Ext::Builder
     # The installation of the bundled gems is failed when DESTDIR is empty in mswin platform.
     destdir = (/\bnmake/i !~ make_program_name || ENV['DESTDIR'] && ENV['DESTDIR'] != "") ? 'DESTDIR=%s' % ENV['DESTDIR'] : ''
 
+    env = [destdir]
+
+    if sitedir
+      env << 'sitearchdir=%s' % sitedir
+      env << 'sitelibdir=%s' % sitedir
+    end
+
     ['clean', '', 'install'].each do |target|
       # Pass DESTDIR via command line to override what's in MAKEFLAGS
       cmd = [
         *make_program,
-        destdir,
+        *env,
         target,
       ].reject(&:empty?)
       begin
diff --git a/lib/rubygems/ext/cargo_builder.rb b/lib/rubygems/ext/cargo_builder.rb
index 8465e9ef05..232c0a313d 100644
--- a/lib/rubygems/ext/cargo_builder.rb
+++ b/lib/rubygems/ext/cargo_builder.rb
@@ -268,29 +268,22 @@ class Gem::Ext::CargoBuilder < Gem::Ext::Builder
       tmp_dest = Dir.mktmpdir(".gem.", extension_dir)
 
       # Some versions of `mktmpdir` return absolute paths, which will break make
-      # if the paths contain spaces. However, on Ruby 1.9.x on Windows, relative
-      # paths cause all C extension builds to fail.
+      # if the paths contain spaces.
       #
-      # As such, we convert to a relative path unless we are using Ruby 1.9.x on
-      # Windows. This means that when using Ruby 1.9.x on Windows, paths with
-      # spaces do not work.
-      #
-      # Details: https://github.com/rubygems/rubygems/issues/977#issuecomment-171544940
+      # As such, we convert to a relative path.
       tmp_dest_relative = get_relative_path(tmp_dest.clone, extension_dir)
 
-      if tmp_dest_relative
-        full_tmp_dest = File.join(extension_dir, tmp_dest_relative)
+      full_tmp_dest = File.join(extension_dir, tmp_dest_relative)
 
-        # TODO: remove in RubyGems 3
-        if Gem.install_extension_in_lib && lib_dir
-          FileUtils.mkdir_p lib_dir
-          FileUtils.cp_r ext_path, lib_dir, remove_destination: true
-        end
+      # TODO: remove in RubyGems 4
+      if Gem.install_extension_in_lib && lib_dir
+        FileUtils.mkdir_p lib_dir
+        FileUtils.cp_r ext_path, lib_dir, remove_destination: true
+      end
 
-        FileUtils::Entry_.new(full_tmp_dest).traverse do |ent|
-          destent = ent.class.new(dest_path, ent.rel)
-          destent.exist? || FileUtils.mv(ent.path, destent.path)
-        end
+      FileUtils::Entry_.new(full_tmp_dest).traverse do |ent|
+        destent = ent.class.new(dest_path, ent.rel)
+        destent.exist? || FileUtils.mv(ent.path, destent.path)
       end
     ensure
       FileUtils.rm_rf tmp_dest if tmp_dest
diff --git a/lib/rubygems/ext/ext_conf_builder.rb b/lib/rubygems/ext/ext_conf_builder.rb
index 3e8aa950c9..2f0183fe2f 100644
--- a/lib/rubygems/ext/ext_conf_builder.rb
+++ b/lib/rubygems/ext/ext_conf_builder.rb
@@ -13,75 +13,50 @@ class Gem::Ext::ExtConfBuilder < Gem::Ext::Builder
     tmp_dest = Dir.mktmpdir(".gem.", extension_dir)
 
     # Some versions of `mktmpdir` return absolute paths, which will break make
-    # if the paths contain spaces. However, on Ruby 1.9.x on Windows, relative
-    # paths cause all C extension builds to fail.
+    # if the paths contain spaces.
     #
-    # As such, we convert to a relative path unless we are using Ruby 1.9.x on
-    # Windows. This means that when using Ruby 1.9.x on Windows, paths with
-    # spaces do not work.
-    #
-    # Details: https://github.com/rubygems/rubygems/issues/977#issuecomment-171544940
+    # As such, we convert to a relative path.
     tmp_dest_relative = get_relative_path(tmp_dest.clone, extension_dir)
 
-    Tempfile.open %w[siteconf .rb], extension_dir do |siteconf|
-      siteconf.puts "require 'rbconfig'"
-      siteconf.puts "dest_path = #{tmp_dest_relative.dump}"
-      %w[sitearchdir sitelibdir].each do |dir|
-        siteconf.puts "RbConfig::MAKEFILE_CONFIG['#{dir}'] = dest_path"
-        siteconf.puts "RbConfig::CONFIG['#{dir}'] = dest_path"
+    destdir = ENV["DESTDIR"]
+
+    begin
+      require "shellwords"
+      cmd = Gem.ruby.shellsplit << "-I" << File.expand_path('../..', __dir__) << File.basename(extension)
+      cmd.push(*args)
+
+      run(cmd, results, class_name, extension_dir) do |s, r|
+        mkmf_log = File.join(extension_dir, 'mkmf.log')
+        if File.exist? mkmf_log
+          unless s.success?
+            r << "To see why this extension failed to compile, please check" \
+              " the mkmf.log which can be found here:\n"
+            r << "  " + File.join(dest_path, 'mkmf.log') + "\n"
+          end
+          FileUtils.mv mkmf_log, dest_path
+        end
       end
 
-      siteconf.close
+      ENV["DESTDIR"] = nil
 
-      destdir = ENV["DESTDIR"]
+      make dest_path, results, extension_dir, tmp_dest_relative
 
-      begin
-        # workaround for https://github.com/oracle/truffleruby/issues/2115
-        siteconf_path = RUBY_ENGINE == "truffleruby" ? siteconf.path.dup : siteconf.path
-        require "shellwords"
-        cmd = Gem.ruby.shellsplit << "-I" << File.expand_path('../..', __dir__) <<
-              "-r" << get_relative_path(siteconf_path, extension_dir) << File.basename(extension)
-        cmd.push(*args)
+      full_tmp_dest = File.join(extension_dir, tmp_dest_relative)
 
-        begin
-          run(cmd, results, class_name, extension_dir) do |s, r|
-            mkmf_log = File.join(extension_dir, 'mkmf.log')
-            if File.exist? mkmf_log
-              unless s.success?
-                r << "To see why this extension failed to compile, please check" \
-                  " the mkmf.log which can be found here:\n"
-                r << "  " + File.join(dest_path, 'mkmf.log') + "\n"
-              end
-              FileUtils.mv mkmf_log, dest_path
-            end
-          end
-          siteconf.unlink
-        end
-
-        ENV["DESTDIR"] = nil
-
-        make dest_path, results, extension_dir
-
-        if tmp_dest_relative
-          full_tmp_dest = File.join(extension_dir, tmp_dest_relative)
-
-          # TODO remove in RubyGems 3
-          if Gem.install_extension_in_lib and lib_dir
-            FileUtils.mkdir_p lib_dir
-            entries = Dir.entries(full_tmp_dest) - %w[. ..]
-            entries = entries.map {|entry| File.join full_tmp_dest, entry }
-            FileUtils.cp_r entries, lib_dir, :remove_destination => true
-          end
-
-          FileUtils::Entry_.new(full_tmp_dest).traverse do |ent|
-            destent = ent.class.new(dest_path, ent.rel)
-            destent.exist? or FileUtils.mv(ent.path, destent.path)
-          end
-        end
-      ensure
-        ENV["DESTDIR"] = destdir
-        siteconf.close!
+      # TODO remove in RubyGems 4
+      if Gem.install_extension_in_lib and lib_dir
+        FileUtils.mkdir_p lib_dir
+        entries = Dir.entries(full_tmp_dest) - %w[. ..]
+        entries = entries.map {|entry| File.join full_tmp_dest, entry }
+        FileUtils.cp_r entries, lib_dir, :remove_destination => true
       end
+
+      FileUtils::Entry_.new(full_tmp_dest).traverse do |ent|
+        destent = ent.class.new(dest_path, ent.rel)
+        destent.exist? or FileUtils.mv(ent.path, destent.path)
+      end
+    ensure
+      ENV["DESTDIR"] = destdir
     end
 
     results
diff --git a/lib/rubygems/indexer.rb b/lib/rubygems/indexer.rb
index 6e8dade640..a5a86f4111 100644
--- a/lib/rubygems/indexer.rb
+++ b/lib/rubygems/indexer.rb
@@ -401,6 +401,8 @@ class Gem::Indexer
 
       File.utime newest_mtime, newest_mtime, dst_name
     end
+  ensure
+    FileUtils.rm_rf @directory
   end
 
   ##
diff --git a/spec/bundler/bundler/definition_spec.rb b/spec/bundler/bundler/definition_spec.rb
index 2618786e7c..13688c2b3d 100644
--- a/spec/bundler/bundler/definition_spec.rb
+++ b/spec/bundler/bundler/definition_spec.rb
@@ -136,7 +136,7 @@ RSpec.describe Bundler::Definition do
             only_java (1.1-java)
 
         PLATFORMS
-          #{lockfile_platforms_for(["java"] + local_platforms)}
+          #{lockfile_platforms_for(["java", specific_local_platform])}
 
         DEPENDENCIES
           only_java
diff --git a/spec/bundler/bundler/friendly_errors_spec.rb b/spec/bundler/bundler/friendly_errors_spec.rb
index 496191f891..69fba7b826 100644
--- a/spec/bundler/bundler/friendly_errors_spec.rb
+++ b/spec/bundler/bundler/friendly_errors_spec.rb
@@ -104,7 +104,6 @@ RSpec.describe Bundler, "friendly errors" do
         expect(Bundler.ui).to receive(:error).with(error.message, :wrap => true)
         Bundler::FriendlyErrors.log_error(error)
       end
-      it_behaves_like "Bundler.ui receive trace", Bundler::BundlerError.new
     end
 
     context "Thor::Error" do
diff --git a/spec/bundler/commands/clean_spec.rb b/spec/bundler/commands/clean_spec.rb
index db81c10e9d..76c7e2adec 100644
--- a/spec/bundler/commands/clean_spec.rb
+++ b/spec/bundler/commands/clean_spec.rb
@@ -792,7 +792,7 @@ RSpec.describe "bundle clean" do
     should_not_have_gems "foo-1.0"
   end
 
-  it "doesn't remove extensions artifacts from bundled git gems after clean", :ruby_repo do
+  it "doesn't remove extensions artifacts from bundled git gems after clean" do
     build_git "very_simple_git_binary", &:add_c_extension
 
     revision = revision_for(lib_path("very_simple_git_binary-1.0"))
@@ -815,7 +815,7 @@ RSpec.describe "bundle clean" do
     expect(vendored_gems("bundler/gems/very_simple_git_binary-1.0-#{revision[0..11]}")).to exist
   end
 
-  it "removes extension directories", :ruby_repo do
+  it "removes extension directories" do
     gemfile <<-G
       source "#{file_uri_for(gem_repo1)}"
 
@@ -851,7 +851,7 @@ RSpec.describe "bundle clean" do
     expect(simple_binary_extensions_dir).to exist
   end
 
-  it "removes git extension directories", :ruby_repo do
+  it "removes git extension directories" do
     build_git "very_simple_git_binary", &:add_c_extension
 
     revision = revision_for(lib_path("very_simple_git_binary-1.0"))
diff --git a/spec/bundler/commands/lock_spec.rb b/spec/bundler/commands/lock_spec.rb
index 11f96315ca..b20a6ded43 100644
--- a/spec/bundler/commands/lock_spec.rb
+++ b/spec/bundler/commands/lock_spec.rb
@@ -217,7 +217,7 @@ RSpec.describe "bundle lock" do
 
     allow(Bundler::SharedHelpers).to receive(:find_gemfile).and_return(bundled_app_gemfile)
     lockfile = Bundler::LockfileParser.new(read_lockfile)
-    expect(lockfile.platforms).to match_array(local_platforms.unshift(java, mingw).uniq)
+    expect(lockfile.platforms).to match_array([java, mingw, specific_local_platform].uniq)
   end
 
   it "supports adding new platforms with force_ruby_platform = true" do
@@ -249,7 +249,7 @@ RSpec.describe "bundle lock" do
 
     allow(Bundler::SharedHelpers).to receive(:find_gemfile).and_return(bundled_app_gemfile)
     lockfile = Bundler::LockfileParser.new(read_lockfile)
-    expect(lockfile.platforms).to match_array(local_platforms.unshift("ruby").uniq)
+    expect(lockfile.platforms).to match_array(["ruby", specific_local_platform].uniq)
   end
 
   it "warns when adding an unknown platform" do
@@ -262,16 +262,16 @@ RSpec.describe "bundle lock" do
 
     allow(Bundler::SharedHelpers).to receive(:find_gemfile).and_return(bundled_app_gemfile)
     lockfile = Bundler::LockfileParser.new(read_lockfile)
-    expect(lockfile.platforms).to match_array(local_platforms.unshift(java, mingw).uniq)
+    expect(lockfile.platforms).to match_array([java, mingw, specific_local_platform].uniq)
 
     bundle "lock --remove-platform java"
 
     lockfile = Bundler::LockfileParser.new(read_lockfile)
-    expect(lockfile.platforms).to match_array(local_platforms.unshift(mingw).uniq)
+    expect(lockfile.platforms).to match_array([mingw, specific_local_platform].uniq)
   end
 
   it "errors when removing all platforms" do
-    bundle "lock --remove-platform #{local_platforms.join(" ")}", :raise_on_error => false
+    bundle "lock --remove-platform #{specific_local_platform}", :raise_on_error => false
     expect(err).to include("Removing all platforms from the bundle is not allowed")
   end
 
diff --git a/spec/bundler/commands/outdated_spec.rb b/spec/bundler/commands/outdated_spec.rb
index 121e39f55a..d0209022a2 100644
--- a/spec/bundler/commands/outdated_spec.rb
+++ b/spec/bundler/commands/outdated_spec.rb
@@ -821,7 +821,7 @@ RSpec.describe "bundle outdated" do
       expect(out).to end_with("Bundle up to date!")
     end
 
-    it "reports that updates are available if the JRuby platform is used", :jruby do
+    it "reports that updates are available if the JRuby platform is used", :jruby_only do
       install_gemfile <<-G
         source "#{file_uri_for(gem_repo2)}"
         gem "laduradura", '= 5.15.2', :platforms => [:ruby, :jruby]
diff --git a/spec/bundler/commands/pristine_spec.rb b/spec/bundler/commands/pristine_spec.rb
index 2f730bd4e2..fe85e1ecd1 100644
--- a/spec/bundler/commands/pristine_spec.rb
+++ b/spec/bundler/commands/pristine_spec.rb
@@ -2,7 +2,7 @@
 
 require "bundler/vendored_fileutils"
 
-RSpec.describe "bundle pristine", :ruby_repo do
+RSpec.describe "bundle pristine" do
   before :each do
     build_lib "baz", :path => bundled_app do |s|
       s.version = "1.0.0"
diff --git a/spec/bundler/install/gemfile/gemspec_spec.rb b/spec/bundler/install/gemfile/gemspec_spec.rb
index 6bcfadab7e..941f1c6db9 100644
--- a/spec/bundler/install/gemfile/gemspec_spec.rb
+++ b/spec/bundler/install/gemfile/gemspec_spec.rb
@@ -8,6 +8,26 @@ RSpec.describe "bundle install from an existing gemspec" do
     end
   end
 
+  let(:x64_mingw_archs) do
+    if RUBY_PLATFORM == "x64-mingw-ucrt"
+      if Gem.rubygems_version >= Gem::Version.new("3.2.28")
+        ["x64-mingw-ucrt", "x64-mingw32"]
+      else
+        ["x64-mingw32", "x64-unknown"]
+      end
+    else
+      ["x64-mingw32"]
+    end
+  end
+
+  let(:x64_mingw_gems) do
+    x64_mingw_archs.map {|p| "platform_specific (1.0-#{p})" }.join("\n    ")
+  end
+
+  let(:x64_mingw_platforms) do
+    x64_mingw_archs.join("\n  ")
+  end
+
   it "should install runtime and development dependencies" do
     build_lib("foo", :path => tmp.join("foo")) do |s|
       s.write("Gemfile", "source :rubygems\ngemspec")
@@ -168,7 +188,7 @@ RSpec.describe "bundle install from an existing gemspec" do
     expect(out.scan(message).size).to eq(1)
   end
 
-  it "should match a lockfile on non-ruby platforms with a transitive platform dependency", :jruby do
+  it "should match a lockfile on non-ruby platforms with a transitive platform dependency", :jruby_only do
     build_lib("foo", :path => tmp.join("foo")) do |s|
       s.add_dependency "platform_specific"
     end
@@ -328,83 +348,65 @@ RSpec.describe "bundle install from an existing gemspec" do
   context "with a lockfile and some missing dependencies" do
     let(:source_uri) { "http://localgemserver.test" }
 
-    context "previously bundled for Ruby" do
-      let(:platform) { "ruby" }
+    before do
+      build_lib("foo", :path => tmp.join("foo")) do |s|
+        s.add_dependency "rack", "=1.0.0"
+      end
 
+      gemfile <<-G
+        source "#{source_uri}"
+        gemspec :path => "../foo"
+      G
+
+      lockfile <<-L
+        PATH
+          remote: ../foo
+          specs:
+            foo (1.0)
+              rack (= 1.0.0)
+
+        GEM
+          remote: #{source_uri}
+          specs:
+            rack (1.0.0)
+
+        PLATFORMS
+          #{generic_local_platform}
+
+        DEPENDENCIES
+          foo!
+
+        BUNDLED WITH
+           #{Bundler::VERSION}
+      L
+    end
+
+    context "using JRuby with explicit platform", :jruby_only do
       before do
-        skip "not installing for some reason" if Gem.win_platform?
-
-        build_lib("foo", :path => tmp.join("foo")) do |s|
-          s.add_dependency "rack", "=1.0.0"
-        end
-
-        gemfile <<-G
-          source "#{source_uri}"
-          gemspec :path => "../foo"
-        G
-
-        lockfile <<-L
-          PATH
-            remote: ../foo
-            specs:
-              foo (1.0)
-                rack (= 1.0.0)
-
-          GEM
-            remote: #{source_uri}
-            specs:
-              rack (1.0.0)
-
-          PLATFORMS
-            #{generic_local_platform}
-
-          DEPENDENCIES
-            foo!
-
-          BUNDLED WITH
-             #{Bundler::VERSION}
-        L
+        create_file(
+          tmp.join("foo", "foo-java.gemspec"),
+          build_spec("foo", "1.0", "java") do
+            dep "rack", "=1.0.0"
+            @spec.authors = "authors"
+            @spec.summary = "summary"
+          end.first.to_ruby
+        )
       end
 
-      context "using JRuby with explicit platform", :jruby do
-        before do
-          create_file(
-            tmp.join("foo", "foo-java.gemspec"),
-            build_spec("foo", "1.0", "java") do
-              dep "rack", "=1.0.0"
-              @spec.authors = "authors"
-              @spec.summary = "summary"
-            end.first.to_ruby
-          )
-        end
-
-        it "should install" do
-          results = bundle "install", :artifice => "endpoint"
-          expect(results).to include("Installing rack 1.0.0")
-          expect(the_bundle).to include_gems "rack 1.0.0"
-        end
-      end
-
-      context "using JRuby", :jruby do
-        it "should install" do
-          results = bundle "install", :artifice => "endpoint"
-          expect(results).to include("Installing rack 1.0.0")
-          expect(the_bundle).to include_gems "rack 1.0.0"
-        end
-      end
-
-      context "using Windows" do
-        it "should install" do
-          simulate_windows do
-            results = bundle "install", :artifice => "endpoint"
-            expect(results).to include("Installing rack 1.0.0")
-            expect(the_bundle).to include_gems "rack 1.0.0"
-          end
-        end
+      it "should install" do
+        results = bundle "install", :artifice => "endpoint"
+        expect(results).to include("Installing rack 1.0.0")
+        expect(the_bundle).to include_gems "rack 1.0.0"
       end
     end
 
-    context "bundled for ruby and jruby" do
+    it "should install", :jruby do
+      results = bundle "install", :artifice => "endpoint"
+      expect(results).to include("Installing rack 1.0.0")
+      expect(the_bundle).to include_gems "rack 1.0.0"
+    end
+
+    context "bundled for multiple platforms" do
       let(:platform_specific_type) { :runtime }
       let(:dependency) { "platform_specific" }
       before do
@@ -434,6 +436,7 @@ RSpec.describe "bundle install from an existing gemspec" do
 
         simulate_new_machine
         simulate_platform("jruby") { bundle "install" }
+        simulate_platform(x64_mingw) { bundle "install" }
       end
 
       context "on ruby" do
@@ -443,7 +446,7 @@ RSpec.describe "bundle install from an existing gemspec" do
         end
 
         context "as a runtime dependency" do
-          it "keeps java dependencies in the lockfile" do
+          it "keeps all platform dependencies in the lockfile" do
             expect(the_bundle).to include_gems "foo 1.0", "platform_specific 1.0 RUBY"
             expect(lockfile).to eq strip_whitespace(<<-L)
               PATH
@@ -457,10 +460,12 @@ RSpec.describe "bundle install from an existing gemspec" do
                 specs:
                   platform_specific (1.0)
                   platform_specific (1.0-java)
+                  #{x64_mingw_gems}
 
               PLATFORMS
                 java
                 ruby
+                #{x64_mingw_platforms}
 
               DEPENDENCIES
                 foo!
@@ -474,7 +479,7 @@ RSpec.describe "bundle install from an existing gemspec" do
         context "as a development dependency" do
           let(:platform_specific_type) { :development }
 
-          it "keeps java dependencies in the lockfile" do
+          it "keeps all platform dependencies in the lockfile" do
             expect(the_bundle).to include_gems "foo 1.0", "platform_specific 1.0 RUBY"
             expect(lockfile).to eq strip_whitespace(<<-L)
               PATH
@@ -487,10 +492,12 @@ RSpec.describe "bundle install from an existing gemspec" do
                 specs:
                   platform_specific (1.0)
                   platform_specific (1.0-java)
+                  #{x64_mingw_gems}
 
               PLATFORMS
                 java
                 ruby
+                #{x64_mingw_platforms}
 
               DEPENDENCIES
                 foo!
@@ -506,7 +513,7 @@ RSpec.describe "bundle install from an existing gemspec" do
           let(:platform_specific_type) { :development }
           let(:dependency) { "indirect_platform_specific" }
 
-          it "keeps java dependencies in the lockfile" do
+          it "keeps all platform dependencies in the lockfile" do
             expect(the_bundle).to include_gems "foo 1.0", "indirect_platform_specific 1.0", "platform_specific 1.0 RUBY"
             expect(lockfile).to eq strip_whitespace(<<-L)
               PATH
@@ -521,10 +528,12 @@ RSpec.describe "bundle install from an existing gemspec" do
                     platform_specific
                   platform_specific (1.0)
                   platform_specific (1.0-java)
+                  #{x64_mingw_gems}
 
               PLATFORMS
                 java
                 ruby
+                #{x64_mingw_platforms}
 
               DEPENDENCIES
                 foo!
@@ -608,7 +617,7 @@ RSpec.describe "bundle install from an existing gemspec" do
 
         PLATFORMS
           ruby
-          x64-mingw32
+          #{x64_mingw_platforms}
           x86-mingw32
 
         DEPENDENCIES
@@ -665,7 +674,7 @@ RSpec.describe "bundle install from an existing gemspec" do
             railties (6.1.4)
 
         PLATFORMS
-          #{lockfile_platforms_for(["java"] + local_platforms)}
+          #{lockfile_platforms_for(["java", specific_local_platform])}
 
         DEPENDENCIES
           activeadmin!
diff --git a/spec/bundler/install/gemfile/git_spec.rb b/spec/bundler/install/gemfile/git_spec.rb
index 07995d013b..3f8a5afc40 100644
--- a/spec/bundler/install/gemfile/git_spec.rb
+++ b/spec/bundler/install/gemfile/git_spec.rb
@@ -92,7 +92,7 @@ RSpec.describe "bundle install with git sources" do
       expect(err).to include("The source contains the following gems matching 'foo':\n  * foo-1.0")
     end
 
-    it "complains with version and platform if pinned specs don't exist in the git repo", :jruby do
+    it "complains with version and platform if pinned specs don't exist in the git repo", :jruby_only do
       build_git "only_java" do |s|
         s.platform = "java"
       end
@@ -107,7 +107,7 @@ RSpec.describe "bundle install with git sources" do
       expect(err).to include("The source contains the following gems matching 'only_java':\n  * only_java-1.0-java")
     end
 
-    it "complains with multiple versions and platforms if pinned specs don't exist in the git repo", :jruby do
+    it "complains with multiple versions and platforms if pinned specs don't exist in the git repo", :jruby_only do
       build_git "only_java", "1.0" do |s|
         s.platform = "java"
       end
@@ -1206,11 +1206,12 @@ RSpec.describe "bundle install with git sources" do
       expect(out).to include(Pathname.glob(default_bundle_path("bundler/gems/extensions/**/foo-1.0-*")).first.to_s)
     end
 
-    it "does not use old extension after ref changes", :ruby_repo do
+    it "does not use old extension after ref changes" do
       git_reader = build_git "foo", :no_default => true do |s|
         s.extensions = ["ext/extconf.rb"]
         s.write "ext/extconf.rb", <<-RUBY
           require "mkmf"
+          $extout = "$(topdir)/" + RbConfig::CONFIG["EXTOUT"] unless RUBY_VERSION < "2.4"
           create_makefile("foo")
         RUBY
         s.write "ext/foo.c", "void Init_foo() {}"
diff --git a/spec/bundler/install/gemfile/platform_spec.rb b/spec/bundler/install/gemfile/platform_spec.rb
index 68d794ed84..d35935e46b 100644
--- a/spec/bundler/install/gemfile/platform_spec.rb
+++ b/spec/bundler/install/gemfile/platform_spec.rb
@@ -50,7 +50,7 @@ RSpec.describe "bundle install across platforms" do
     expect(the_bundle).to include_gems "platform_specific 1.0 JAVA"
   end
 
-  it "pulls the pure ruby version on jruby if the java platform is not present in the lockfile and bundler is run in frozen mode", :jruby do
+  it "pulls the pure ruby version on jruby if the java platform is not present in the lockfile and bundler is run in frozen mode", :jruby_only do
     lockfile <<-G
       GEM
         remote: #{file_uri_for(gem_repo1)}
@@ -332,8 +332,6 @@ end
 
 RSpec.describe "bundle install with platform conditionals" do
   it "installs gems tagged w/ the current platforms" do
-    skip "platform issues" if Gem.win_platform?
-
     install_gemfile <<-G
       source "#{file_uri_for(gem_repo1)}"
 
@@ -402,8 +400,6 @@ RSpec.describe "bundle install with platform conditionals" do
   end
 
   it "installs gems tagged w/ the current platforms inline" do
-    skip "platform issues" if Gem.win_platform?
-
     install_gemfile <<-G
       source "#{file_uri_for(gem_repo1)}"
       gem "nokogiri", :platforms => :#{local_tag}
@@ -422,8 +418,6 @@ RSpec.describe "bundle install with platform conditionals" do
   end
 
   it "installs gems tagged w/ the current platform inline" do
-    skip "platform issues" if Gem.win_platform?
-
     install_gemfile <<-G
       source "#{file_uri_for(gem_repo1)}"
       gem "nokogiri", :platform => :#{local_tag}
diff --git a/spec/bundler/install/gemfile/specific_platform_spec.rb b/spec/bundler/install/gemfile/specific_platform_spec.rb
index 113a0a1352..276a84f2a6 100644
--- a/spec/bundler/install/gemfile/specific_platform_spec.rb
+++ b/spec/bundler/install/gemfile/specific_platform_spec.rb
@@ -250,10 +250,11 @@ RSpec.describe "bundle install with specific platforms" do
     end
   end
 
-  it "installs sorbet-static, which does not provide a pure ruby variant, just fine on truffleruby", :truffleruby do
+  it "installs sorbet-static, which does not provide a pure ruby variant, just fine", :truffleruby do
+    skip "does not apply to Windows" if Gem.win_platform?
+
     build_repo2 do
-      build_gem("sorbet-static", "0.5.6403") {|s| s.platform = "x86_64-linux" }
-      build_gem("sorbet-static", "0.5.6403") {|s| s.platform = "universal-darwin-20" }
+      build_gem("sorbet-static", "0.5.6403") {|s| s.platform = Bundler.local_platform }
     end
 
     gemfile <<~G
@@ -266,8 +267,7 @@ RSpec.describe "bundle install with specific platforms" do
       GEM
         remote: #{file_uri_for(gem_repo2)}/
         specs:
-          sorbet-static (0.5.6403-universal-darwin-20)
-          sorbet-static (0.5.6403-x86_64-linux)
+          sorbet-static (0.5.6403-#{Bundler.local_platform})
 
       PLATFORMS
         ruby
@@ -283,54 +283,95 @@ RSpec.describe "bundle install with specific platforms" do
   end
 
   it "does not resolve if the current platform does not match any of available platform specific variants for a top level dependency" do
-    build_repo2 do
+    build_repo4 do
       build_gem("sorbet-static", "0.5.6433") {|s| s.platform = "x86_64-linux" }
       build_gem("sorbet-static", "0.5.6433") {|s| s.platform = "universal-darwin-20" }
     end
 
     gemfile <<~G
-      source "#{file_uri_for(gem_repo2)}"
+      source "#{file_uri_for(gem_repo4)}"
 
       gem "sorbet-static", "0.5.6433"
     G
 
-    simulate_platform "arm64-darwin-21" do
-      bundle "install", :raise_on_error => false
-    end
-
-    expect(err).to include <<~ERROR.rstrip
-      Could not find gem 'sorbet-static (= 0.5.6433) arm64-darwin-21' in rubygems repository #{file_uri_for(gem_repo2)}/ or installed locally.
+    error_message = <<~ERROR.strip
+      Could not find gem 'sorbet-static (= 0.5.6433)' with platform 'arm64-darwin-21' in rubygems repository #{file_uri_for(gem_repo4)}/ or installed locally.
 
       The source contains the following gems matching 'sorbet-static (= 0.5.6433)':
         * sorbet-static-0.5.6433-universal-darwin-20
         * sorbet-static-0.5.6433-x86_64-linux
     ERROR
+
+    simulate_platform "arm64-darwin-21" do
+      bundle "lock", :raise_on_error => false
+    end
+
+    expect(err).to include(error_message).once
+
+    # Make sure it doesn't print error twice in verbose mode
+
+    simulate_platform "arm64-darwin-21" do
+      bundle "lock --verbose", :raise_on_error => false
+    end
+
+    expect(err).to include(error_message).once
   end
 
   it "does not resolve if the current platform does not match any of available platform specific variants for a transitive dependency" do
-    build_repo2 do
+    build_repo4 do
       build_gem("sorbet", "0.5.6433") {|s| s.add_dependency "sorbet-static", "= 0.5.6433" }
       build_gem("sorbet-static", "0.5.6433") {|s| s.platform = "x86_64-linux" }
       build_gem("sorbet-static", "0.5.6433") {|s| s.platform = "universal-darwin-20" }
     end
 
     gemfile <<~G
-      source "#{file_uri_for(gem_repo2)}"
+      source "#{file_uri_for(gem_repo4)}"
 
       gem "sorbet", "0.5.6433"
     G
 
-    simulate_platform "arm64-darwin-21" do
-      bundle "install", :raise_on_error => false
-    end
-
-    expect(err).to include <<~ERROR.rstrip
-      Could not find gem 'sorbet-static (= 0.5.6433) arm64-darwin-21', which is required by gem 'sorbet (= 0.5.6433)', in rubygems repository #{file_uri_for(gem_repo2)}/ or installed locally.
+    error_message = <<~ERROR.strip
+      Could not find gem 'sorbet-static (= 0.5.6433)' with platform 'arm64-darwin-21', which is required by gem 'sorbet (= 0.5.6433)', in rubygems repository #{file_uri_for(gem_repo4)}/ or installed locally.
 
       The source contains the following gems matching 'sorbet-static (= 0.5.6433)':
         * sorbet-static-0.5.6433-universal-darwin-20
         * sorbet-static-0.5.6433-x86_64-linux
     ERROR
+
+    simulate_platform "arm64-darwin-21" do
+      bundle "lock", :raise_on_error => false
+    end
+
+    expect(err).to include(error_message).once
+
+    # Make sure it doesn't print error twice in verbose mode
+
+    simulate_platform "arm64-darwin-21" do
+      bundle "lock --verbose", :raise_on_error => false
+    end
+
+    expect(err).to include(error_message).once
+  end
+
+  it "does not generate a lockfile if RUBY platform is forced and some gem has no RUBY variant available" do
+    build_repo4 do
+      build_gem("sorbet-static", "0.5.9889") {|s| s.platform = Gem::Platform.local }
+    end
+
+    gemfile <<~G
+      source "#{file_uri_for(gem_repo4)}"
+
+      gem "sorbet-static", "0.5.9889"
+    G
+
+    bundle "lock", :raise_on_error => false, :env => { "BUNDLE_FORCE_RUBY_PLATFORM" => "true" }
+
+    expect(err).to include <<~ERROR.rstrip
+      Could not find gem 'sorbet-static (= 0.5.9889)' with platform 'ruby' in rubygems repository #{file_uri_for(gem_repo4)}/ or installed locally.
+
+      The source contains the following gems matching 'sorbet-static (= 0.5.9889)':
+        * sorbet-static-0.5.9889-#{Gem::Platform.local}
+    ERROR
   end
 
   private
diff --git a/spec/bundler/install/gemfile_spec.rb b/spec/bundler/install/gemfile_spec.rb
index 0f8f1ecfa8..e643573454 100644
--- a/spec/bundler/install/gemfile_spec.rb
+++ b/spec/bundler/install/gemfile_spec.rb
@@ -66,7 +66,7 @@ RSpec.describe "bundle install" do
     end
   end
 
-  context "with engine specified in symbol", :jruby do
+  context "with engine specified in symbol", :jruby_only do
     it "does not raise any error parsing Gemfile" do
       install_gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
diff --git a/spec/bundler/install/gems/native_extensions_spec.rb b/spec/bundler/install/gems/native_extensions_spec.rb
index d5cafcfc2c..c3e05586bd 100644
--- a/spec/bundler/install/gems/native_extensions_spec.rb
+++ b/spec/bundler/install/gems/native_extensions_spec.rb
@@ -1,12 +1,13 @@
 # frozen_string_literal: true
 
-RSpec.describe "installing a gem with native extensions", :ruby_repo do
+RSpec.describe "installing a gem with native extensions" do
   it "installs" do
     build_repo2 do
       build_gem "c_extension" do |s|
         s.extensions = ["ext/extconf.rb"]
         s.write "ext/extconf.rb", <<-E
           require "mkmf"
+          $extout = "$(topdir)/" + RbConfig::CONFIG["EXTOUT"] unless RUBY_VERSION < "2.4"
           name = "c_extension_bundle"
           dir_config(name)
           raise "OMG" unless with_config("c_extension") == "hello"
@@ -51,6 +52,7 @@ RSpec.describe "installing a gem with native extensions", :ruby_repo do
       s.extensions = ["ext/extconf.rb"]
       s.write "ext/extconf.rb", <<-E
         require "mkmf"
+        $extout = "$(topdir)/" + RbConfig::CONFIG["EXTOUT"] unless RUBY_VERSION < "2.4"
         name = "c_extension_bundle"
         dir_config(name)
         raise "OMG" unless with_config("c_extension") == "hello"
@@ -95,6 +97,7 @@ RSpec.describe "installing a gem with native extensions", :ruby_repo do
           s.extensions = ["ext/extconf.rb"]
           s.write "ext/extconf.rb", <<-E
             require "mkmf"
+            $extout = "$(topdir)/" + RbConfig::CONFIG["EXTOUT"] unless RUBY_VERSION < "2.4"
             name = "c_extension_bundle_#{n}"
             dir_config(name)
             raise "OMG" unless with_config("c_extension_#{n}") == "#{n}"
@@ -147,6 +150,7 @@ RSpec.describe "installing a gem with native extensions", :ruby_repo do
       s.extensions = ["ext/extconf.rb"]
       s.write "ext/extconf.rb", <<-E
         require "mkmf"
+        $extout = "$(topdir)/" + RbConfig::CONFIG["EXTOUT"] unless RUBY_VERSION < "2.4"
         name = "c_extension_bundle"
         dir_config(name)
         raise "OMG" unless with_config("c_extension") == "hello" && with_config("c_extension_bundle-dir") == "hola"
diff --git a/spec/bundler/install/gems/resolving_spec.rb b/spec/bundler/install/gems/resolving_spec.rb
index f23d137bc1..b136dea8bd 100644
--- a/spec/bundler/install/gems/resolving_spec.rb
+++ b/spec/bundler/install/gems/resolving_spec.rb
@@ -187,11 +187,7 @@ RSpec.describe "bundle install with install-time dependencies" do
 
         bundle :install, :env => { "DEBUG_RESOLVER_TREE" => "1", "DEBUG" => "1" }
 
-        activated_groups = if local_platforms.any?
-          "net_b (1.0) (ruby), net_b (1.0) (#{local_platforms.join(", ")})"
-        else
-          "net_b (1.0) (ruby)"
-        end
+        activated_groups = "net_b (1.0) (ruby), net_b (1.0) (#{specific_local_platform})"
 
         expect(out).to include(" net_b").
           and include("BUNDLER: Starting resolution").
diff --git a/spec/bundler/install/gems/standalone_spec.rb b/spec/bundler/install/gems/standalone_spec.rb
index 0bbd829148..a5302877c1 100644
--- a/spec/bundler/install/gems/standalone_spec.rb
+++ b/spec/bundler/install/gems/standalone_spec.rb
@@ -32,6 +32,21 @@ RSpec.shared_examples "bundle install --standalone" do
       expect(out).to eq(expected_gems.values.join("\n"))
     end
 
+    it "makes the gems available without bundler nor rubygems" do
+      testrb = String.new <<-RUBY
+        $:.unshift File.expand_path("bundle")
+        require "bundler/setup"
+
+      RUBY
+      expected_gems.each do |k, _|
+        testrb << "\nrequire \"#{k}\""
+        testrb << "\nputs #{k.upcase}"
+      end
+      sys_exec %(#{Gem.ruby} --disable-gems -w -e #{testrb.shellescape})
+
+      expect(out).to eq(expected_gems.values.join("\n"))
+    end
+
     it "makes the gems available without bundler via Kernel.require" do
       testrb = String.new <<-RUBY
         $:.unshift File.expand_path("bundle")
@@ -154,8 +169,8 @@ RSpec.shared_examples "bundle install --standalone" do
       load_path_lines = bundled_app("bundle/bundler/setup.rb").read.split("\n").select {|line| line.start_with?("$:.unshift") }
 
       expect(load_path_lines).to eq [
-        '$:.unshift File.expand_path("#{__dir__}/../#{RUBY_ENGINE}/#{RbConfig::CONFIG["ruby_version"]}/gems/bar-1.0.0/lib")',
-        '$:.unshift File.expand_path("#{__dir__}/../#{RUBY_ENGINE}/#{RbConfig::CONFIG["ruby_version"]}/gems/foo-1.0.0/lib")',
+        '$:.unshift File.expand_path("#{__dir__}/../#{RUBY_ENGINE}/#{Gem.ruby_api_version}/gems/bar-1.0.0/lib")',
+        '$:.unshift File.expand_path("#{__dir__}/../#{RUBY_ENGINE}/#{Gem.ruby_api_version}/gems/foo-1.0.0/lib")',
       ]
     end
   end
@@ -190,7 +205,7 @@ RSpec.shared_examples "bundle install --standalone" do
     end
   end
 
-  describe "with gems with native extension", :ruby_repo do
+  describe "with gems with native extension" do
     before do
       bundle "config set --local path #{bundled_app("bundle")}"
       install_gemfile <<-G, :standalone => true, :dir => cwd
@@ -201,9 +216,13 @@ RSpec.shared_examples "bundle install --standalone" do
 
     it "generates a bundle/bundler/setup.rb with the proper paths" do
       expected_path = bundled_app("bundle/bundler/setup.rb")
-      extension_line = File.read(expected_path).each_line.find {|line| line.include? "/extensions/" }.strip
-      expect(extension_line).to start_with '$:.unshift File.expand_path("#{__dir__}/../#{RUBY_ENGINE}/#{RbConfig::CONFIG["ruby_version"]}/extensions/'
-      expect(extension_line).to end_with '/very_simple_binary-1.0")'
+      script_content = File.read(expected_path)
+      expect(script_content).to include("def self.ruby_api_version")
+      expect(script_content).to include("def self.extension_api_version")
+      extension_line = script_content.each_line.find {|line| line.include? "/extensions/" }.strip
+      platform = Gem::Platform.local
+      expect(extension_line).to start_with '$:.unshift File.expand_path("#{__dir__}/../#{RUBY_ENGINE}/#{Gem.ruby_api_version}/extensions/'
+      expect(extension_line).to end_with platform.to_s + '/#{Gem.extension_api_version}/very_simple_binary-1.0")'
     end
   end
 
diff --git a/spec/bundler/install/global_cache_spec.rb b/spec/bundler/install/global_cache_spec.rb
index afa0ff76c1..3021d6ae17 100644
--- a/spec/bundler/install/global_cache_spec.rb
+++ b/spec/bundler/install/global_cache_spec.rb
@@ -205,7 +205,7 @@ RSpec.describe "global gem caching" do
   end
 
   describe "extension caching" do
-    it "works", :ruby_repo do
+    it "works" do
       skip "gets incorrect ref in path" if Gem.win_platform?
 
       build_git "very_simple_git_binary", &:add_c_extension
diff --git a/spec/bundler/install/path_spec.rb b/spec/bundler/install/path_spec.rb
index b0392c4ed2..bd5385b265 100644
--- a/spec/bundler/install/path_spec.rb
+++ b/spec/bundler/install/path_spec.rb
@@ -176,7 +176,7 @@ RSpec.describe "bundle install" do
       expect(the_bundle).to include_gems "rack 1.0.0"
     end
 
-    it "re-installs gems whose extensions have been deleted", :ruby_repo do
+    it "re-installs gems whose extensions have been deleted" do
       build_lib "very_simple_binary", "1.0.0", :to_system => true do |s|
         s.write "lib/very_simple_binary.rb", "raise 'FAIL'"
       end
diff --git a/spec/bundler/lock/lockfile_spec.rb b/spec/bundler/lock/lockfile_spec.rb
index 8ec0a80bd0..ea9893fb0e 100644
--- a/spec/bundler/lock/lockfile_spec.rb
+++ b/spec/bundler/lock/lockfile_spec.rb
@@ -982,7 +982,7 @@ RSpec.describe "the lockfile format" do
           rack (1.0.0)
 
       PLATFORMS
-        #{lockfile_platforms_for(["java"] + local_platforms)}
+        #{lockfile_platforms_for(["java", specific_local_platform])}
 
       DEPENDENCIES
         rack
diff --git a/spec/bundler/other/ext_spec.rb b/spec/bundler/other/ext_spec.rb
index e13f62a856..9b829a2b36 100644
--- a/spec/bundler/other/ext_spec.rb
+++ b/spec/bundler/other/ext_spec.rb
@@ -44,6 +44,10 @@ RSpec.describe "Bundler::GemHelpers#generic" do
     expect(generic(pl("x64-mingw32"))).to eq(pl("x64-mingw32"))
     expect(generic(pl("x86_64-mingw32"))).to eq(pl("x64-mingw32"))
   end
+
+  it "converts 64-bit mingw UCRT platform variants into x64-mingw-ucrt" do
+    expect(generic(pl("x64-mingw-ucrt"))).to eq(pl("x64-mingw-ucrt"))
+  end
 end
 
 RSpec.describe "Gem::SourceIndex#refresh!" do
diff --git a/spec/bundler/other/platform_spec.rb b/spec/bundler/other/platform_spec.rb
index bf38a05646..c157345cab 100644
--- a/spec/bundler/other/platform_spec.rb
+++ b/spec/bundler/other/platform_spec.rb
@@ -2,10 +2,6 @@
 
 RSpec.describe "bundle platform" do
   context "without flags" do
-    let(:bundle_platform_platforms_string) do
-      local_platforms.reverse.map {|pl| "* #{pl}" }.join("\n")
-    end
-
     it "returns all the output" do
       gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
@@ -20,7 +16,7 @@ RSpec.describe "bundle platform" do
 Your platform is: #{Gem::Platform.local}
 
 Your app has gems that work on these platforms:
-#{bundle_platform_platforms_string}
+* #{specific_local_platform}
 
 Your Gemfile specifies a Ruby version requirement:
 * ruby #{RUBY_VERSION}
@@ -43,7 +39,7 @@ G
 Your platform is: #{Gem::Platform.local}
 
 Your app has gems that work on these platforms:
-#{bundle_platform_platforms_string}
+* #{specific_local_platform}
 
 Your Gemfile specifies a Ruby version requirement:
 * ruby #{RUBY_VERSION}p#{RUBY_PATCHLEVEL}
@@ -64,7 +60,7 @@ G
 Your platform is: #{Gem::Platform.local}
 
 Your app has gems that work on these platforms:
-#{bundle_platform_platforms_string}
+* #{specific_local_platform}
 
 Your Gemfile does not specify a Ruby version requirement.
 G
@@ -84,7 +80,7 @@ G
 Your platform is: #{Gem::Platform.local}
 
 Your app has gems that work on these platforms:
-#{bundle_platform_platforms_string}
+* #{specific_local_platform}
 
 Your Gemfile specifies a Ruby version requirement:
 * ruby #{not_local_ruby_version}
@@ -305,7 +301,7 @@ G
       expect(bundled_app_lock).to exist
     end
 
-    it "installs fine with any engine", :jruby do
+    it "installs fine with any engine", :jruby_only do
       install_gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem "rack"
@@ -351,7 +347,7 @@ G
       should_be_engine_incorrect
     end
 
-    it "doesn't install when engine version doesn't match", :jruby do
+    it "doesn't install when engine version doesn't match", :jruby_only do
       install_gemfile <<-G, :raise_on_error => false
         source "#{file_uri_for(gem_repo1)}"
         gem "rack"
@@ -394,7 +390,7 @@ G
       expect(out).to match(/\AResolving dependencies\.\.\.\.*\nThe Gemfile's dependencies are satisfied\z/)
     end
 
-    it "checks fine with any engine", :jruby do
+    it "checks fine with any engine", :jruby_only do
       install_gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem "rack"
@@ -445,7 +441,7 @@ G
       should_be_engine_incorrect
     end
 
-    it "fails when engine version doesn't match", :jruby do
+    it "fails when engine version doesn't match", :jruby_only do
       install_gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem "rack"
@@ -511,7 +507,7 @@ G
       expect(the_bundle).to include_gems "rack 1.2", "rack-obama 1.0", "activesupport 3.0"
     end
 
-    it "updates fine with any engine", :jruby do
+    it "updates fine with any engine", :jruby_only do
       gemfile <<-G
         source "#{file_uri_for(gem_repo2)}"
         gem "activesupport"
@@ -547,7 +543,7 @@ G
       should_be_ruby_version_incorrect
     end
 
-    it "fails when ruby engine doesn't match", :jruby do
+    it "fails when ruby engine doesn't match", :jruby_only do
       gemfile <<-G
         source "#{file_uri_for(gem_repo2)}"
         gem "activesupport"
@@ -563,7 +559,7 @@ G
       should_be_engine_incorrect
     end
 
-    it "fails when ruby engine version doesn't match", :jruby do
+    it "fails when ruby engine version doesn't match", :jruby_only do
       gemfile <<-G
         source "#{file_uri_for(gem_repo2)}"
         gem "activesupport"
@@ -615,7 +611,7 @@ G
       expect(out).to eq(default_bundle_path("gems", "rails-2.3.2").to_s)
     end
 
-    it "prints path if ruby version is correct for any engine", :jruby do
+    it "prints path if ruby version is correct for any engine", :jruby_only do
       install_gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem "rails"
@@ -651,7 +647,7 @@ G
       should_be_engine_incorrect
     end
 
-    it "fails if engine version doesn't match", :bundler => "< 3", :jruby => true do
+    it "fails if engine version doesn't match", :bundler => "< 3", :jruby_only => true do
       gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem "rails"
@@ -699,7 +695,7 @@ G
       expect(bundled_app("vendor/cache/rack-1.0.0.gem")).to exist
     end
 
-    it "copies the .gem file to vendor/cache when ruby version matches for any engine", :jruby do
+    it "copies the .gem file to vendor/cache when ruby version matches for any engine", :jruby_only do
       install_gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem 'rack'
@@ -735,7 +731,7 @@ G
       should_be_engine_incorrect
     end
 
-    it "fails if the engine version doesn't match", :jruby do
+    it "fails if the engine version doesn't match", :jruby_only do
       gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem 'rack'
@@ -780,7 +776,7 @@ G
       expect(bundled_app("vendor/cache/rack-1.0.0.gem")).to exist
     end
 
-    it "copies the .gem file to vendor/cache when ruby version matches any engine", :jruby do
+    it "copies the .gem file to vendor/cache when ruby version matches any engine", :jruby_only do
       install_gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem 'rack'
@@ -816,7 +812,7 @@ G
       should_be_engine_incorrect
     end
 
-    it "fails if the engine version doesn't match", :jruby do
+    it "fails if the engine version doesn't match", :jruby_only do
       gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem 'rack'
@@ -859,7 +855,7 @@ G
       expect(out).to include("0.9.1")
     end
 
-    it "activates the correct gem when ruby version matches any engine", :jruby do
+    it "activates the correct gem when ruby version matches any engine", :jruby_only do
       system_gems "rack-1.0.0", "rack-0.9.1", :path => default_bundle_path
       gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
@@ -896,7 +892,7 @@ G
       should_be_engine_incorrect
     end
 
-    # it "fails when the engine version doesn't match", :jruby do
+    # it "fails when the engine version doesn't match", :jruby_only do
     #   gemfile <<-G
     #     gem "rack", "0.9.1"
     #
@@ -947,7 +943,7 @@ G
       expect(out).to include("0.9.1")
     end
 
-    it "starts IRB with the default group loaded when ruby version matches", :readline, :jruby do
+    it "starts IRB with the default group loaded when ruby version matches", :readline, :jruby_only do
       gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem "rack"
@@ -992,7 +988,7 @@ G
       should_be_engine_incorrect
     end
 
-    it "fails when engine version doesn't match", :jruby do
+    it "fails when engine version doesn't match", :jruby_only do
       gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem "rack"
@@ -1047,7 +1043,7 @@ G
       expect(bundled_app_lock).to exist
     end
 
-    it "makes a Gemfile.lock if setup succeeds for any engine", :jruby do
+    it "makes a Gemfile.lock if setup succeeds for any engine", :jruby_only do
       install_gemfile <<-G
         source "#{file_uri_for(gem_repo1)}"
         gem "yard"
@@ -1096,7 +1092,7 @@ G
       should_be_engine_incorrect
     end
 
-    it "fails when engine version doesn't match", :jruby do
+    it "fails when engine version doesn't match", :jruby_only do
       install_gemfile <<-G, :raise_on_error => false
         source "#{file_uri_for(gem_repo1)}"
         gem "yard"
@@ -1169,7 +1165,7 @@ G
       expect(out).to match(Regexp.new(expected_output))
     end
 
-    it "returns list of outdated gems when the ruby version matches for any engine", :jruby do
+    it "returns list of outdated gems when the ruby version matches for any engine", :jruby_only do
       bundle :install
       update_repo2 do
         build_gem "activesupport", "3.0"
@@ -1231,7 +1227,7 @@ G
       should_be_engine_incorrect
     end
 
-    it "fails when the engine version doesn't match", :jruby do
+    it "fails when the engine version doesn't match", :jruby_only do
       update_repo2 do
         build_gem "activesupport", "3.0"
         update_git "foo", :path => lib_path("foo")
@@ -1249,7 +1245,7 @@ G
       should_be_engine_version_incorrect
     end
 
-    it "fails when the patchlevel doesn't match", :jruby do
+    it "fails when the patchlevel doesn't match", :jruby_only do
       update_repo2 do
         build_gem "activesupport", "3.0"
         update_git "foo", :path => lib_path("foo")
@@ -1267,7 +1263,7 @@ G
       should_be_patchlevel_incorrect
     end
 
-    it "fails when the patchlevel is a fixnum", :jruby do
+    it "fails when the patchlevel is a fixnum", :jruby_only do
       update_repo2 do
         build_gem "activesupport", "3.0"
         update_git "foo", :path => lib_path("foo")
diff --git a/spec/bundler/resolver/platform_spec.rb b/spec/bundler/resolver/platform_spec.rb
index bc4081f8b5..9931c9080b 100644
--- a/spec/bundler/resolver/platform_spec.rb
+++ b/spec/bundler/resolver/platform_spec.rb
@@ -291,7 +291,7 @@ RSpec.describe "Resolving platform craziness" do
   describe "with mingw32" do
     before :each do
       @index = build_index do
-        platforms "mingw32 mswin32 x64-mingw32" do |platform|
+        platforms "mingw32 mswin32 x64-mingw32 x64-mingw-ucrt" do |platform|
           gem "thin", "1.2.7", platform
         end
         gem "win32-api", "1.5.1", "universal-mingw32"
@@ -312,7 +312,7 @@ RSpec.describe "Resolving platform craziness" do
       should_resolve_as %w[thin-1.2.7-mingw32]
     end
 
-    it "finds x64-mingw gems" do
+    it "finds x64-mingw32 gems" do
       platforms "x64-mingw32"
       dep "thin"
       should_resolve_as %w[thin-1.2.7-x64-mingw32]
@@ -329,6 +329,14 @@ RSpec.describe "Resolving platform craziness" do
       dep "win32-api"
       should_resolve_as %w[win32-api-1.5.1-universal-mingw32]
     end
+
+    if Gem.rubygems_version >= Gem::Version.new("3.2.28")
+      it "finds x64-mingw-ucrt gems" do
+        platforms "x64-mingw-ucrt"
+        dep "thin"
+        should_resolve_as %w[thin-1.2.7-x64-mingw-ucrt]
+      end
+    end
   end
 
   describe "with conflicting cases" do
diff --git a/spec/bundler/runtime/platform_spec.rb b/spec/bundler/runtime/platform_spec.rb
index f7159635e6..f97969402c 100644
--- a/spec/bundler/runtime/platform_spec.rb
+++ b/spec/bundler/runtime/platform_spec.rb
@@ -86,7 +86,7 @@ RSpec.describe "Bundler.setup with multi platform stuff" do
           racc (1.5.2)
 
       PLATFORMS
-        #{lockfile_platforms_for(["ruby"] + local_platforms)}
+        #{lockfile_platforms_for(["ruby", specific_local_platform])}
 
       DEPENDENCIES
         nokogiri (~> 1.11)
@@ -145,7 +145,7 @@ RSpec.describe "Bundler.setup with multi platform stuff" do
     expect(the_bundle).not_to include_gems "nokogiri 1.11.1 #{Bundler.local_platform}"
   end
 
-  it "will use the java platform if both generic java and generic ruby platforms are locked", :jruby do
+  it "will use the java platform if both generic java and generic ruby platforms are locked", :jruby_only do
     gemfile <<-G
       source "#{file_uri_for(gem_repo1)}"
       gem "nokogiri"
@@ -204,7 +204,7 @@ RSpec.describe "Bundler.setup with multi platform stuff" do
     expect(the_bundle).to include_gems "nokogiri 1.4.2", "platform_specific 1.0 x86-darwin-100"
   end
 
-  it "allows specifying only-ruby-platform on jruby", :jruby do
+  it "allows specifying only-ruby-platform on jruby", :jruby_only do
     install_gemfile <<-G
       source "#{file_uri_for(gem_repo1)}"
       gem "nokogiri"
@@ -246,7 +246,7 @@ RSpec.describe "Bundler.setup with multi platform stuff" do
     expect(the_bundle).to include_gems "nokogiri 1.4.2", "platform_specific 1.0 RUBY"
   end
 
-  it "doesn't pull platform specific gems on truffleruby", :truffleruby do
+  it "doesn't pull platform specific gems on truffleruby", :truffleruby_only do
     install_gemfile <<-G
      source "#{file_uri_for(gem_repo1)}"
      gem "platform_specific"
diff --git a/spec/bundler/runtime/require_spec.rb b/spec/bundler/runtime/require_spec.rb
index d91b5f8666..e59fa564f6 100644
--- a/spec/bundler/runtime/require_spec.rb
+++ b/spec/bundler/runtime/require_spec.rb
@@ -449,8 +449,6 @@ RSpec.describe "Bundler.require with platform specific dependencies" do
   end
 
   it "requires gems pinned to multiple platforms, including the current one" do
-    skip "platform issues" if Gem.win_platform?
-
     install_gemfile <<-G
       source "#{file_uri_for(gem_repo1)}"
 
diff --git a/spec/bundler/runtime/setup_spec.rb b/spec/bundler/runtime/setup_spec.rb
index 91f8aaf78a..0d7573752a 100644
--- a/spec/bundler/runtime/setup_spec.rb
+++ b/spec/bundler/runtime/setup_spec.rb
@@ -827,7 +827,7 @@ end
     expect(out).to eq("yay")
   end
 
-  it "should clean $LOAD_PATH properly", :ruby_repo do
+  it "should clean $LOAD_PATH properly" do
     gem_name = "very_simple_binary"
     full_gem_name = gem_name + "-1.0"
     ext_dir = File.join(tmp("extensions", full_gem_name))
diff --git a/spec/bundler/spec_helper.rb b/spec/bundler/spec_helper.rb
index 23db133b67..892ad10e98 100644
--- a/spec/bundler/spec_helper.rb
+++ b/spec/bundler/spec_helper.rb
@@ -74,6 +74,8 @@ RSpec.configure do |config|
     ENV["BUNDLER_SPEC_RUN"] = "true"
     ENV["BUNDLER_NO_OLD_RUBYGEMS_WARNING"] = "true"
     ENV["BUNDLE_USER_CONFIG"] = ENV["BUNDLE_USER_CACHE"] = ENV["BUNDLE_USER_PLUGIN"] = nil
+    ENV["BUNDLE_APP_CONFIG"] = nil
+    ENV["BUNDLE_SILENCE_ROOT_WARNING"] = nil
     ENV["RUBYGEMS_GEMDEPS"] = nil
     ENV["XDG_CONFIG_HOME"] = nil
     ENV["GEMRC"] = nil
diff --git a/spec/bundler/support/builders.rb b/spec/bundler/support/builders.rb
index 91f0106d7d..285b68c047 100644
--- a/spec/bundler/support/builders.rb
+++ b/spec/bundler/support/builders.rb
@@ -121,6 +121,10 @@ module Spec
           s.platform = "x64-mingw32"
         end
 
+        build_gem "platform_specific" do |s|
+          s.platform = "x64-mingw-ucrt"
+        end
+
         build_gem "platform_specific" do |s|
           s.platform = "x86-darwin-100"
           s.write "lib/platform_specific.rb", "PLATFORM_SPECIFIC = '1.0.0 x86-darwin-100'"
@@ -444,8 +448,7 @@ module Spec
         write "ext/extconf.rb", <<-RUBY
           require "mkmf"
 
-
-          # exit 1 unless with_config("simple")
+          $extout = "$(topdir)/" + RbConfig::CONFIG["EXTOUT"] unless RUBY_VERSION < "2.4"
 
           extension_name = "#{name}_c"
           if extra_lib_dir = with_config("ext-lib")
diff --git a/spec/bundler/support/filters.rb b/spec/bundler/support/filters.rb
index 96f2e2a274..c3b7a425ae 100644
--- a/spec/bundler/support/filters.rb
+++ b/spec/bundler/support/filters.rb
@@ -33,8 +33,8 @@ RSpec.configure do |config|
   config.filter_run_excluding :no_color_tty => Gem.win_platform? || !ENV["GITHUB_ACTION"].nil?
   config.filter_run_excluding :permissions => Gem.win_platform?
   config.filter_run_excluding :readline => Gem.win_platform?
-  config.filter_run_excluding :jruby => RUBY_ENGINE != "jruby"
-  config.filter_run_excluding :truffleruby => RUBY_ENGINE != "truffleruby"
+  config.filter_run_excluding :jruby_only => RUBY_ENGINE != "jruby"
+  config.filter_run_excluding :truffleruby_only => RUBY_ENGINE != "truffleruby"
   config.filter_run_excluding :man => Gem.win_platform?
 
   config.filter_run_when_matching :focus unless ENV["CI"]
diff --git a/spec/bundler/support/matchers.rb b/spec/bundler/support/matchers.rb
index 3c2a7f9f58..ce6b216619 100644
--- a/spec/bundler/support/matchers.rb
+++ b/spec/bundler/support/matchers.rb
@@ -178,7 +178,7 @@ module Spec
 
             begin
               require '#{name}'
-              name_constant = '#{Spec::Builders.constantize(name)}'
+              name_constant = #{Spec::Builders.constantize(name)}
               if #{version.nil?} || name_constant == '#{version}'
                 exit 64
               else
diff --git a/spec/bundler/support/platforms.rb b/spec/bundler/support/platforms.rb
index 07973fd727..48479723e4 100644
--- a/spec/bundler/support/platforms.rb
+++ b/spec/bundler/support/platforms.rb
@@ -55,13 +55,15 @@ module Spec
     def local_tag
       if RUBY_PLATFORM == "java"
         :jruby
+      elsif ["x64-mingw32", "x64-mingw-ucrt"].include?(RUBY_PLATFORM)
+        :x64_mingw
       else
         :ruby
       end
     end
 
     def not_local_tag
-      [:ruby, :jruby].find {|tag| tag != local_tag }
+      [:jruby, :x64_mingw, :ruby].find {|tag| tag != local_tag }
     end
 
     def local_ruby_engine
@@ -74,7 +76,7 @@ module Spec
 
     def not_local_engine_version
       case not_local_tag
-      when :ruby
+      when :ruby, :x64_mingw
         not_local_ruby_version
       when :jruby
         "1.6.1"
@@ -90,15 +92,11 @@ module Spec
     end
 
     def lockfile_platforms
-      lockfile_platforms_for(local_platforms)
+      lockfile_platforms_for([specific_local_platform])
     end
 
     def lockfile_platforms_for(platforms)
       platforms.map(&:to_s).sort.join("\n  ")
     end
-
-    def local_platforms
-      [specific_local_platform]
-    end
   end
 end
diff --git a/test/rubygems/helper.rb b/test/rubygems/helper.rb
index 75eed7be6b..7bd7dd0c3b 100644
--- a/test/rubygems/helper.rb
+++ b/test/rubygems/helper.rb
@@ -119,6 +119,12 @@ class Gem::TestCase < Test::Unit::TestCase
     assert File.directory?(path), msg
   end
 
+  def refute_directory_exists(path, msg = nil)
+    msg = build_message(msg, "Expected path '#{path}' not to be a directory")
+    assert_path_not_exist path
+    refute File.directory?(path), msg
+  end
+
   # https://github.com/seattlerb/minitest/blob/21d9e804b63c619f602f3f4ece6c71b48974707a/lib/minitest/assertions.rb#L188
   def _synchronize
     yield
diff --git a/test/rubygems/test_gem_commands_environment_command.rb b/test/rubygems/test_gem_commands_environment_command.rb
index 2bf80d8d85..eeddb2befe 100644
--- a/test/rubygems/test_gem_commands_environment_command.rb
+++ b/test/rubygems/test_gem_commands_environment_command.rb
@@ -25,6 +25,8 @@ class TestGemCommandsEnvironmentCommand < Gem::TestCase
     assert_match %r{RUBY VERSION: \d+\.\d+\.\d+ \(.*\) \[.*\]}, @ui.output
     assert_match %r{INSTALLATION DIRECTORY: #{Regexp.escape @gemhome}},
                  @ui.output
+    assert_match %r{USER INSTALLATION DIRECTORY: #{Regexp.escape Gem.user_dir}},
+                 @ui.output
     assert_match %r{RUBYGEMS PREFIX: }, @ui.output
     assert_match %r{RUBY EXECUTABLE:.*#{RbConfig::CONFIG['ruby_install_name']}},
                  @ui.output
@@ -63,6 +65,28 @@ class TestGemCommandsEnvironmentCommand < Gem::TestCase
     assert_equal '', @ui.error
   end
 
+  def test_execute_user_gemdir
+    @cmd.send :handle_options, %w[user_gemdir]
+
+    use_ui @ui do
+      @cmd.execute
+    end
+
+    assert_equal "#{Gem.user_dir}\n", @ui.output
+    assert_equal '', @ui.error
+  end
+
+  def test_execute_user_gemhome
+    @cmd.send :handle_options, %w[user_gemhome]
+
+    use_ui @ui do
+      @cmd.execute
+    end
+
+    assert_equal "#{Gem.user_dir}\n", @ui.output
+    assert_equal '', @ui.error
+  end
+
   def test_execute_gempath
     @cmd.send :handle_options, %w[gempath]
 
diff --git a/test/rubygems/test_gem_ext_cargo_builder/custom_name/Cargo.lock b/test/rubygems/test_gem_ext_cargo_builder/custom_name/Cargo.lock
index cb1bdb3c61..447ab9ac38 100644
--- a/test/rubygems/test_gem_ext_cargo_builder/custom_name/Cargo.lock
+++ b/test/rubygems/test_gem_ext_cargo_builder/custom_name/Cargo.lock
@@ -11,47 +11,23 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "ansi_term"
-version = "0.12.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d52a9bb7ec0cf484c551830a7ce27bd20d67eac647e1befb56b0be4ee39a55d2"
-dependencies = [
- "winapi",
-]
-
-[[package]]
-name = "atty"
-version = "0.2.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
-dependencies = [
- "hermit-abi",
- "libc",
- "winapi",
-]
-
 [[package]]
 name = "bindgen"
-version = "0.59.2"
+version = "0.60.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2bd2a9a458e8f4304c52c43ebb0cfbd520289f8379a52e329a38afda99bf8eb8"
+checksum = "062dddbc1ba4aca46de6338e2bf87771414c335f7b2f2036e8f3e9befebf88e6"
 dependencies = [
  "bitflags",
  "cexpr",
  "clang-sys",
- "clap",
- "env_logger",
  "lazy_static",
  "lazycell",
- "log",
  "peeking_take_while",
  "proc-macro2",
  "quote",
  "regex",
  "rustc-hash",
  "shlex",
- "which",
 ]
 
 [[package]]
@@ -60,12 +36,6 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
-[[package]]
-name = "cc"
-version = "1.0.73"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2fff2a6927b3bb87f9595d67196a70493f627687a71d87a0d692242c33f58c11"
-
 [[package]]
 name = "cexpr"
 version = "0.6.0"
@@ -92,21 +62,6 @@ dependencies = [
  "libloading",
 ]
 
-[[package]]
-name = "clap"
-version = "2.34.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a0610544180c38b88101fecf2dd634b174a62eef6946f84dfc6a7127512b381c"
-dependencies = [
- "ansi_term",
- "atty",
- "bitflags",
- "strsim",
- "textwrap",
- "unicode-width",
- "vec_map",
-]
-
 [[package]]
 name = "custom-name-ext"
 version = "0.1.0"
@@ -114,46 +69,12 @@ dependencies = [
  "rb-sys",
 ]
 
-[[package]]
-name = "either"
-version = "1.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
-
-[[package]]
-name = "env_logger"
-version = "0.9.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b2cf0344971ee6c64c31be0d530793fba457d322dfec2810c453d0ef228f9c3"
-dependencies = [
- "atty",
- "humantime",
- "log",
- "regex",
- "termcolor",
-]
-
 [[package]]
 name = "glob"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9b919933a397b79c37e33b77bb2aa3dc8eb6e165ad809e58ff75bc7db2e34574"
 
-[[package]]
-name = "hermit-abi"
-version = "0.1.19"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
-dependencies = [
- "libc",
-]
-
-[[package]]
-name = "humantime"
-version = "2.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a3a5bfb195931eeb336b2a7b4d761daec841b97f947d34394601737a7bba5e4"
-
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -191,15 +112,6 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "log"
-version = "0.4.17"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
-dependencies = [
- "cfg-if",
-]
-
 [[package]]
 name = "memchr"
 version = "2.5.0"
@@ -228,41 +140,42 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "19b17cddbe7ec3f8bc800887bab5e717348c95ea2ca0b1bf0837fb964dc67099"
 
-[[package]]
-name = "pkg-config"
-version = "0.3.25"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1df8c4ec4b0627e53bdf214615ad287367e482558cf84b109250b37464dc03ae"
-
 [[package]]
 name = "proc-macro2"
-version = "1.0.39"
+version = "1.0.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c54b25569025b7fc9651de43004ae593a75ad88543b17178aa5e1b9c4f15f56f"
+checksum = "dd96a1e8ed2596c337f8eae5f24924ec83f5ad5ab21ea8e455d3566c69fbcaf7"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.18"
+version = "1.0.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1feb54ed693b93a84e14094943b84b7c4eae204c512b7ccb95ab0c66d278ad1"
+checksum = "3bcdf212e9776fbcb2d23ab029360416bb1706b1aea2d1a5ba002727cbcab804"
 dependencies = [
  "proc-macro2",
 ]
 
 [[package]]
 name = "rb-sys"
-version = "0.9.4"
+version = "0.9.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f5465c5bd695ef70959b91b4ca9cfd515e9af012f6d9f0ae46f09fa4bcc3b722"
+checksum = "104c5bcb9fa23bf3823124c003c516b22664fef50c4a481ff2d0e21b76e0f92c"
 dependencies = [
  "bindgen",
- "cc",
- "lazy_static",
  "linkify",
- "pkg-config",
+ "rb-sys-build",
+]
+
+[[package]]
+name = "rb-sys-build"
+version = "0.9.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4cdf919b75ba95aa480159f3b20070cbec110d6c8a7af86b35844270069a4cb3"
+dependencies = [
+ "regex",
  "shell-words",
 ]
 
@@ -301,58 +214,11 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "43b2853a4d09f215c24cc5489c992ce46052d359b5109343cbafbf26bc62f8a3"
 
-[[package]]
-name = "strsim"
-version = "0.8.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
-
-[[package]]
-name = "termcolor"
-version = "1.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bab24d30b911b2376f3a13cc2cd443142f0c81dda04c118693e35b3835757755"
-dependencies = [
- "winapi-util",
-]
-
-[[package]]
-name = "textwrap"
-version = "0.11.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
-dependencies = [
- "unicode-width",
-]
-
 [[package]]
 name = "unicode-ident"
-version = "1.0.0"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d22af068fba1eb5edcb4aea19d382b2a3deb4c8f9d475c589b6ada9e0fd493ee"
-
-[[package]]
-name = "unicode-width"
-version = "0.1.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ed742d4ea2bd1176e236172c8429aaf54486e7ac098db29ffe6529e0ce50973"
-
-[[package]]
-name = "vec_map"
-version = "0.8.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
-
-[[package]]
-name = "which"
-version = "4.2.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5c4fb54e6113b6a8772ee41c3404fb0301ac79604489467e0a9ce1f3e97c24ae"
-dependencies = [
- "either",
- "lazy_static",
- "libc",
-]
+checksum = "5bd2fe26506023ed7b5e1e315add59d6f584c621d037f9368fea9cfb988f368c"
 
 [[package]]
 name = "winapi"
@@ -370,15 +236,6 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
-[[package]]
-name = "winapi-util"
-version = "0.1.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
-dependencies = [
- "winapi",
-]
-
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
diff --git a/test/rubygems/test_gem_ext_cargo_builder/custom_name/Cargo.toml b/test/rubygems/test_gem_ext_cargo_builder/custom_name/Cargo.toml
index cbc9225140..d84ffe611e 100644
--- a/test/rubygems/test_gem_ext_cargo_builder/custom_name/Cargo.toml
+++ b/test/rubygems/test_gem_ext_cargo_builder/custom_name/Cargo.toml
@@ -1,9 +1,10 @@
 [package]
 name = "custom-name-ext"
 version = "0.1.0"
+edition = "2021"
 
 [lib]
 crate-type = ["cdylib"]
 
 [dependencies]
-rb-sys = "0.9.4" 
+rb-sys = { version = "0.9.15", features = ["gem"] }
diff --git a/test/rubygems/test_gem_ext_cargo_builder/custom_name/src/lib.rs b/test/rubygems/test_gem_ext_cargo_builder/custom_name/src/lib.rs
index ca9cf4e656..543ad4a70e 100644
--- a/test/rubygems/test_gem_ext_cargo_builder/custom_name/src/lib.rs
+++ b/test/rubygems/test_gem_ext_cargo_builder/custom_name/src/lib.rs
@@ -1,11 +1,8 @@
-#[macro_use]
 extern crate rb_sys;
 
 use rb_sys::{rb_define_module, rb_define_module_function, rb_utf8_str_new, VALUE};
 use std::ffi::CString;
 
-ruby_extension!();
-
 #[no_mangle]
 unsafe extern "C" fn say_hello(_klass: VALUE) -> VALUE {
     let cstr = CString::new("Hello world!").unwrap();
diff --git a/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/Cargo.lock b/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/Cargo.lock
index edbeda8420..25937fe892 100644
--- a/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/Cargo.lock
+++ b/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/Cargo.lock
@@ -11,47 +11,23 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "ansi_term"
-version = "0.12.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d52a9bb7ec0cf484c551830a7ce27bd20d67eac647e1befb56b0be4ee39a55d2"
-dependencies = [
- "winapi",
-]
-
-[[package]]
-name = "atty"
-version = "0.2.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
-dependencies = [
- "hermit-abi",
- "libc",
- "winapi",
-]
-
 [[package]]
 name = "bindgen"
-version = "0.59.2"
+version = "0.60.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2bd2a9a458e8f4304c52c43ebb0cfbd520289f8379a52e329a38afda99bf8eb8"
+checksum = "062dddbc1ba4aca46de6338e2bf87771414c335f7b2f2036e8f3e9befebf88e6"
 dependencies = [
  "bitflags",
  "cexpr",
  "clang-sys",
- "clap",
- "env_logger",
  "lazy_static",
  "lazycell",
- "log",
  "peeking_take_while",
  "proc-macro2",
  "quote",
  "regex",
  "rustc-hash",
  "shlex",
- "which",
 ]
 
 [[package]]
@@ -60,12 +36,6 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
-[[package]]
-name = "cc"
-version = "1.0.73"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2fff2a6927b3bb87f9595d67196a70493f627687a71d87a0d692242c33f58c11"
-
 [[package]]
 name = "cexpr"
 version = "0.6.0"
@@ -92,61 +62,12 @@ dependencies = [
  "libloading",
 ]
 
-[[package]]
-name = "clap"
-version = "2.34.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a0610544180c38b88101fecf2dd634b174a62eef6946f84dfc6a7127512b381c"
-dependencies = [
- "ansi_term",
- "atty",
- "bitflags",
- "strsim",
- "textwrap",
- "unicode-width",
- "vec_map",
-]
-
-[[package]]
-name = "either"
-version = "1.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
-
-[[package]]
-name = "env_logger"
-version = "0.9.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b2cf0344971ee6c64c31be0d530793fba457d322dfec2810c453d0ef228f9c3"
-dependencies = [
- "atty",
- "humantime",
- "log",
- "regex",
- "termcolor",
-]
-
 [[package]]
 name = "glob"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9b919933a397b79c37e33b77bb2aa3dc8eb6e165ad809e58ff75bc7db2e34574"
 
-[[package]]
-name = "hermit-abi"
-version = "0.1.19"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
-dependencies = [
- "libc",
-]
-
-[[package]]
-name = "humantime"
-version = "2.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a3a5bfb195931eeb336b2a7b4d761daec841b97f947d34394601737a7bba5e4"
-
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -184,15 +105,6 @@ dependencies = [
  "memchr",
 ]
 
-[[package]]
-name = "log"
-version = "0.4.17"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
-dependencies = [
- "cfg-if",
-]
-
 [[package]]
 name = "memchr"
 version = "2.5.0"
@@ -221,41 +133,42 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "19b17cddbe7ec3f8bc800887bab5e717348c95ea2ca0b1bf0837fb964dc67099"
 
-[[package]]
-name = "pkg-config"
-version = "0.3.25"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1df8c4ec4b0627e53bdf214615ad287367e482558cf84b109250b37464dc03ae"
-
 [[package]]
 name = "proc-macro2"
-version = "1.0.39"
+version = "1.0.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c54b25569025b7fc9651de43004ae593a75ad88543b17178aa5e1b9c4f15f56f"
+checksum = "dd96a1e8ed2596c337f8eae5f24924ec83f5ad5ab21ea8e455d3566c69fbcaf7"
 dependencies = [
  "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.18"
+version = "1.0.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a1feb54ed693b93a84e14094943b84b7c4eae204c512b7ccb95ab0c66d278ad1"
+checksum = "3bcdf212e9776fbcb2d23ab029360416bb1706b1aea2d1a5ba002727cbcab804"
 dependencies = [
  "proc-macro2",
 ]
 
 [[package]]
 name = "rb-sys"
-version = "0.9.4"
+version = "0.9.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f5465c5bd695ef70959b91b4ca9cfd515e9af012f6d9f0ae46f09fa4bcc3b722"
+checksum = "104c5bcb9fa23bf3823124c003c516b22664fef50c4a481ff2d0e21b76e0f92c"
 dependencies = [
  "bindgen",
- "cc",
- "lazy_static",
  "linkify",
- "pkg-config",
+ "rb-sys-build",
+]
+
+[[package]]
+name = "rb-sys-build"
+version = "0.9.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4cdf919b75ba95aa480159f3b20070cbec110d6c8a7af86b35844270069a4cb3"
+dependencies = [
+ "regex",
  "shell-words",
 ]
 
@@ -301,58 +214,11 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "43b2853a4d09f215c24cc5489c992ce46052d359b5109343cbafbf26bc62f8a3"
 
-[[package]]
-name = "strsim"
-version = "0.8.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
-
-[[package]]
-name = "termcolor"
-version = "1.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bab24d30b911b2376f3a13cc2cd443142f0c81dda04c118693e35b3835757755"
-dependencies = [
- "winapi-util",
-]
-
-[[package]]
-name = "textwrap"
-version = "0.11.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
-dependencies = [
- "unicode-width",
-]
-
 [[package]]
 name = "unicode-ident"
-version = "1.0.0"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d22af068fba1eb5edcb4aea19d382b2a3deb4c8f9d475c589b6ada9e0fd493ee"
-
-[[package]]
-name = "unicode-width"
-version = "0.1.9"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ed742d4ea2bd1176e236172c8429aaf54486e7ac098db29ffe6529e0ce50973"
-
-[[package]]
-name = "vec_map"
-version = "0.8.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
-
-[[package]]
-name = "which"
-version = "4.2.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5c4fb54e6113b6a8772ee41c3404fb0301ac79604489467e0a9ce1f3e97c24ae"
-dependencies = [
- "either",
- "lazy_static",
- "libc",
-]
+checksum = "5bd2fe26506023ed7b5e1e315add59d6f584c621d037f9368fea9cfb988f368c"
 
 [[package]]
 name = "winapi"
@@ -370,15 +236,6 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
-[[package]]
-name = "winapi-util"
-version = "0.1.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
-dependencies = [
- "winapi",
-]
-
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
diff --git a/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/Cargo.toml b/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/Cargo.toml
index 3aec0690b0..534303b598 100644
--- a/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/Cargo.toml
+++ b/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/Cargo.toml
@@ -1,9 +1,10 @@
 [package]
 name = "rust_ruby_example"
 version = "0.1.0"
+edition = "2021"
 
 [lib]
 crate-type = ["cdylib"]
 
 [dependencies]
-rb-sys = "0.9.4"
+rb-sys = { version = "0.9.15", features = ["gem"] }
diff --git a/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/src/lib.rs b/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/src/lib.rs
index 26bddaeaf1..b2a907c736 100644
--- a/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/src/lib.rs
+++ b/test/rubygems/test_gem_ext_cargo_builder/rust_ruby_example/src/lib.rs
@@ -1,4 +1,3 @@
-#[macro_use]
 extern crate rb_sys;
 
 use rb_sys::{
@@ -7,8 +6,6 @@ use rb_sys::{
 use std::ffi::{CStr, CString};
 use std::os::raw::{c_char, c_long};
 
-ruby_extension!();
-
 #[inline]
 unsafe fn cstr_to_string(str: *const c_char) -> String {
     CStr::from_ptr(str).to_string_lossy().into_owned()
diff --git a/test/rubygems/test_gem_indexer.rb b/test/rubygems/test_gem_indexer.rb
index 6653f29adf..24afae5fcc 100644
--- a/test/rubygems/test_gem_indexer.rb
+++ b/test/rubygems/test_gem_indexer.rb
@@ -103,6 +103,8 @@ class TestGemIndexer < Gem::TestCase
 
     assert_indexed @indexerdir, "latest_specs.#{@marshal_version}"
     assert_indexed @indexerdir, "latest_specs.#{@marshal_version}.gz"
+
+    refute_directory_exists @indexer.directory
   end
 
   def test_generate_index_modern
@@ -342,6 +344,8 @@ class TestGemIndexer < Gem::TestCase
 
       assert_includes pre_specs_index, @d2_1_a_tuple
       refute_includes pre_specs_index, @d2_1_tuple
+
+      refute_directory_exists @indexer.directory
     end
   end
 
diff --git a/test/rubygems/test_gem_package.rb b/test/rubygems/test_gem_package.rb
index 34660bdccd..e3dce87c95 100644
--- a/test/rubygems/test_gem_package.rb
+++ b/test/rubygems/test_gem_package.rb
@@ -737,9 +737,7 @@ class TestGemPackage < Gem::Package::TarTestCase
     file = 'foo//file.rb'.dup
     file.taint if RUBY_VERSION < '2.7'
 
-    destination = @destination.sub '/', '//'
-
-    destination = package.install_location file, destination
+    destination = package.install_location file, @destination
 
     assert_equal File.join(@destination, 'foo', 'file.rb'), destination
     refute destination.tainted? if RUBY_VERSION < '2.7'
diff --git a/test/rubygems/test_rubygems.rb b/test/rubygems/test_rubygems.rb
index 739a9985b0..e5c0a22caf 100644
--- a/test/rubygems/test_rubygems.rb
+++ b/test/rubygems/test_rubygems.rb
@@ -16,7 +16,7 @@ class GemTest < Gem::TestCase
     output = Gem::Util.popen(*ruby_with_rubygems_and_fake_operating_system_in_load_path(path), '-e', "'require \"rubygems\"'", { :err => [:child, :out] }).strip
     assert !$?.success?
     assert_includes output, "undefined local variable or method `intentionally_not_implemented_method'"
-    assert_includes output, "Loading the rubygems/defaults/operating_system.rb file caused an error. " \
+    assert_includes output, "Loading the #{operating_system_rb_at(path)} file caused an error. " \
     "This file is owned by your OS, not by rubygems upstream. " \
     "Please find out which OS package this file belongs to and follow the guidelines from your OS to report " \
     "the problem and ask for help."
@@ -53,16 +53,19 @@ class GemTest < Gem::TestCase
 
   def util_install_operating_system_rb(content)
     dir_lib = Dir.mktmpdir("test_operating_system_lib", @tempdir)
-    dir_lib_arg = File.join dir_lib
+    dir_lib_arg = File.join dir_lib, "lib"
 
-    dir_lib_rubygems_defaults_arg = File.join dir_lib_arg, "lib", "rubygems", "defaults"
-    FileUtils.mkdir_p dir_lib_rubygems_defaults_arg
+    operating_system_rb = operating_system_rb_at(dir_lib_arg)
 
-    operating_system_rb = File.join dir_lib_rubygems_defaults_arg, "operating_system.rb"
+    FileUtils.mkdir_p File.dirname(operating_system_rb)
 
     File.open(operating_system_rb, 'w') {|f| f.write content }
 
-    File.join dir_lib_arg, "lib"
+    dir_lib_arg
+  end
+
+  def operating_system_rb_at(dir)
+    File.join dir, "rubygems", "defaults", "operating_system.rb"
   end
 
   def ruby_with_rubygems_and_fake_operating_system_in_load_path(operating_system_path)
diff --git a/tool/bundler/dev_gems.rb.lock b/tool/bundler/dev_gems.rb.lock
index f800741de8..13288110ef 100644
--- a/tool/bundler/dev_gems.rb.lock
+++ b/tool/bundler/dev_gems.rb.lock
@@ -33,6 +33,8 @@ PLATFORMS
   java
   ruby
   universal-java-11
+  universal-java-18
+  x64-mingw-ucrt
   x64-mingw32
   x86_64-darwin-20
   x86_64-linux
@@ -51,4 +53,4 @@ DEPENDENCIES
   webrick (~> 1.6)
 
 BUNDLED WITH
-   2.3.16
+   2.3.17
diff --git a/tool/bundler/rubocop_gems.rb.lock b/tool/bundler/rubocop_gems.rb.lock
index 45e66a8b84..a6f5bb353c 100644
--- a/tool/bundler/rubocop_gems.rb.lock
+++ b/tool/bundler/rubocop_gems.rb.lock
@@ -47,6 +47,8 @@ PLATFORMS
   arm64-darwin-20
   arm64-darwin-21
   universal-java-11
+  universal-java-18
+  x64-mingw-ucrt
   x86_64-darwin-19
   x86_64-darwin-20
   x86_64-linux
@@ -60,4 +62,4 @@ DEPENDENCIES
   test-unit
 
 BUNDLED WITH
-   2.3.16
+   2.3.17
diff --git a/tool/bundler/standard_gems.rb.lock b/tool/bundler/standard_gems.rb.lock
index 99e7e2aff5..10b7af19ab 100644
--- a/tool/bundler/standard_gems.rb.lock
+++ b/tool/bundler/standard_gems.rb.lock
@@ -53,6 +53,8 @@ PLATFORMS
   arm64-darwin-20
   arm64-darwin-21
   universal-java-11
+  universal-java-18
+  x64-mingw-ucrt
   x86_64-darwin-19
   x86_64-darwin-20
   x86_64-linux
@@ -66,4 +68,4 @@ DEPENDENCIES
   test-unit
 
 BUNDLED WITH
-   2.3.16
+   2.3.17
diff --git a/tool/bundler/test_gems.rb.lock b/tool/bundler/test_gems.rb.lock
index a79bc65e8d..dc4dc3d8ad 100644
--- a/tool/bundler/test_gems.rb.lock
+++ b/tool/bundler/test_gems.rb.lock
@@ -26,6 +26,8 @@ PLATFORMS
   java
   ruby
   universal-java-11
+  universal-java-18
+  x64-mingw-ucrt
   x64-mingw32
   x86_64-darwin-20
   x86_64-linux
@@ -41,4 +43,4 @@ DEPENDENCIES
   webrick (= 1.7.0)
 
 BUNDLED WITH
-   2.3.16
+   2.3.17