Windows: Read ENV names and values as UTF-8 encoded Strings (#3818)

* Windows: Read ENV names and values as UTF-8 encoded Strings

Implements issue #12650: fix https://bugs.ruby-lang.org/issues/12650

This also removes the special encoding for ENV['PATH'] and some
complexity in the code that is unnecessary now.

* Windows: Improve readablity of getenv() encoding

getenv() did use the expected codepage as an implicit parameter of the macro.
This is mis-leading since include/ruby/win32.h has a different definition.
Using the "cp" variable explicit (like the other function calls) makes it
more readable and consistent.

* Windows: Change external C-API macros getenv() and execv() to use UTF-8

They used to process and return strings with locale encoding,
but since all ruby-internal spawn and environment functions use UTF-8,
it makes sense to change the C-API equally.

2 files changed, 16 insertions, 13 deletions

diff --git a/test/ruby/test_env.rb b/test/ruby/test_env.rb
index 7735b53045..ddfce136a4 100644
--- a/test/ruby/test_env.rb
+++ b/test/ruby/test_env.rb
@@ -369,7 +369,8 @@ class TestEnv < Test::Unit::TestCase
       assert_equal("foo", v)
     end
     assert_invalid_env {|var| ENV.assoc(var)}
-    assert_equal(Encoding.find("locale"), v.encoding)
+    encoding = /mswin|mingw/ =~ RUBY_PLATFORM ? Encoding::UTF_8 : Encoding.find("locale")
+    assert_equal(encoding, v.encoding)
   end
 
   def test_has_value2
@@ -579,15 +580,13 @@ class TestEnv < Test::Unit::TestCase
       end;
     end
 
-    if Encoding.find("locale") == Encoding::UTF_8
-      def test_utf8
-        text = "testing \u{e5 e1 e2 e4 e3 101 3042}"
-        test = ENV["test"]
-        ENV["test"] = text
-        assert_equal text, ENV["test"]
-      ensure
-        ENV["test"] = test
-      end
+    def test_utf8
+      text = "testing \u{e5 e1 e2 e4 e3 101 3042}"
+      test = ENV["test"]
+      ENV["test"] = text
+      assert_equal text, ENV["test"]
+    ensure
+      ENV["test"] = test
     end
   end
 end
diff --git a/test/ruby/test_m17n.rb b/test/ruby/test_m17n.rb
index 2c6dc3f8f5..3f28d55ac1 100644
--- a/test/ruby/test_m17n.rb
+++ b/test/ruby/test_m17n.rb
@@ -1325,10 +1325,14 @@ class TestM17N < Test::Unit::TestCase
   end
 
   def test_env
-    locale_encoding = Encoding.find("locale")
+    if RUBY_PLATFORM =~ /bccwin|mswin|mingw/
+      env_encoding = Encoding::UTF_8
+    else
+      env_encoding = Encoding.find("locale")
+    end
     ENV.each {|k, v|
-      assert_equal(locale_encoding, k.encoding, k)
-      assert_equal(locale_encoding, v.encoding, v)
+      assert_equal(env_encoding, k.encoding, k)
+      assert_equal(env_encoding, v.encoding, v)
     }
   end