Set default for Encoding.default_external to UTF-8 on Windows (#2877)

* Use UTF-8 as default for Encoding.default_external on Windows
* Document UTF-8 change on Windows to Encoding.default_external

fix https://bugs.ruby-lang.org/issues/16604

2 files changed, 3 insertions, 3 deletions

diff --git a/spec/ruby/command_line/dash_upper_k_spec.rb b/spec/ruby/command_line/dash_upper_k_spec.rb
index a060eab793..7e71532295 100644
--- a/spec/ruby/command_line/dash_upper_k_spec.rb
+++ b/spec/ruby/command_line/dash_upper_k_spec.rb
@@ -58,8 +58,8 @@ describe 'The -K command line option' do
   end
 
   it "ignores unknown codes" do
-    locale = Encoding.find('locale')
+    external = Encoding.find('external')
     ruby_exe(@test_string, options: '-KZ').should ==
-      [Encoding::UTF_8.name, locale.name, nil].inspect
+      [Encoding::UTF_8.name, external.name, nil].inspect
   end
 end
diff --git a/spec/ruby/library/stringio/binmode_spec.rb b/spec/ruby/library/stringio/binmode_spec.rb
index 83178787f3..853d9c9bd6 100644
--- a/spec/ruby/library/stringio/binmode_spec.rb
+++ b/spec/ruby/library/stringio/binmode_spec.rb
@@ -9,7 +9,7 @@ describe "StringIO#binmode" do
 
   it "changes external encoding to BINARY" do
     io = StringIO.new
-    io.external_encoding.should == Encoding.find('locale')
+    io.external_encoding.should == Encoding.find('external')
     io.binmode
     io.external_encoding.should == Encoding::BINARY
   end