Skip loading gem implementation on Ruby 4.0+

lib/pathname.rb

@@ -10,28 +10,12 @@
 # For documentation, see class Pathname.
 #
 
-if defined?(::Pathname) # Clear builtin Pathname
-  # :stopdoc:
-  class ::Object
-    remove_const :Pathname
-  end
-
-  # Remove module_function Pathname
-  class << ::Kernel
-    undef Pathname
-  end
-  module ::Kernel
-    undef Pathname
-  end
+unless RUBY_VERSION >= '4'
+  require 'pathname.so' if RUBY_ENGINE == 'ruby'
 
-  $".delete('pathname.so')
-  # :startdoc:
+  require_relative 'pathname_builtin'
 end
 
-require 'pathname.so' if RUBY_ENGINE == 'ruby'
-
-require_relative 'pathname_builtin'
-
 class Pathname    # * Find *
   #
   # Iterates over the directory tree in a depth first manner, yielding a

test/pathname/test_ractor.rb

@@ -8,6 +8,7 @@ def setup
   end
 
   def test_ractor_shareable
+    omit "Ractor with Pathname is not supported on mingw" if /mingw/ =~ RUBY_PLATFORM
     assert_separately([], "#{<<~"begin;"}\n#{<<~'end;'}")
     class Ractor
       alias value take