(GH-1759) Preserve encoding of commands in powershell transport

When conveying data from the WinRM transport back to the powershell
shell class, we use a set of pipes. Those pipes acquire the default
external encoding of Ruby, even though the winrm gem ensures that the
content will always be UTF-8. We now properly tag those pipes as UTF-8
to avoid the data being misinterpreted.

In order to preserve \r\n line endings for Windows targets, the
powershell shell class then puts those pipes into binmode. That causes
the character encoding information to be stripped away entirely. We now
save that encoding information before converting the pipe and we
reassert the encoding on the string after reading it.

This addresses an issue where systems with non-UTF-8 encodings would
have valid UTF-8 data misinterpreted as invalid data in their native
character encoding.

!bug

  * **Improved support for non-UTF-8 character encodings**
    ([#1759](#1759))

    Commands run from a target where the default character encoding is
    non-UTF-8 will now return proper results when using the WinRM
    transport.

Author: nicklewis

lib/bolt/shell/powershell.rb

@@ -267,10 +267,18 @@ def execute(command)
 
         result = Bolt::Node::Output.new
         inp.close
-        out.binmode
-        err.binmode
-        stdout = Thread.new { result.stdout << out.read }
-        stderr = Thread.new { result.stderr << err.read }
+        stdout = Thread.new do
+          # Set to binmode to preserve \r\n line endings, but save and restore
+          # the proper encoding so the string isn't later misinterpreted
+          encoding = out.external_encoding
+          out.binmode
+          result.stdout << out.read.force_encoding(encoding)
+        end
+        stderr = Thread.new do
+          encoding = err.external_encoding
+          err.binmode
+          result.stderr << err.read.force_encoding(encoding)
+        end
 
         stdout.join
         stderr.join

lib/bolt/transport/winrm/connection.rb

@@ -108,8 +108,8 @@ def execute(command)
           # it will fail if the shell attempts to provide stdin
           inp.close
 
-          out_rd, out_wr = IO.pipe
-          err_rd, err_wr = IO.pipe
+          out_rd, out_wr = IO.pipe('UTF-8')
+          err_rd, err_wr = IO.pipe('UTF-8')
           th = Thread.new do
             result = @session.run(command)
             out_wr << result.stdout