monkeypatch Socket on jruby+windows to return UTF-8 strings

Fixes #2507

lib/logstash/event.rb

@@ -296,7 +296,6 @@ class LogStash::Event
   def self.validate_value(value)
     case value
     when String
-      value.force_encoding("UTF-8") if LogStash::Environment.windows?
       raise("expected UTF-8 encoding for value=#{value}, encoding=#{value.encoding.inspect}") unless value.encoding == Encoding::UTF_8
       raise("invalid UTF-8 encoding for value=#{value}, encoding=#{value.encoding.inspect}") unless value.valid_encoding?
       value

lib/logstash/monkeypatches-for-bugs.rb

@@ -0,0 +1,34 @@
+require "logstash/environment"
+
+if LogStash::Environment.windows? && LogStash::Environment.jruby? then
+  require "socket"
+  module JRubyBug2558SocketPeerAddrBugFix
+    def peeraddr
+      orig_peeraddr.map do |v|
+        case v
+        when String
+          v.force_encoding(Encoding::UTF_8)
+        else
+          v
+        end
+      end
+    end
+  end
+
+  class << Socket
+    # Bugfix for jruby #2558
+    alias_method :orig_gethostname, :gethostname
+    def gethostname
+      return orig_gethostname.force_encoding(Encoding::UTF_8)
+    end
+  end
+
+  class TCPSocket
+    alias_method :orig_peeraddr, :peeraddr
+    include JRubyBug2558SocketPeerAddrBugFix
+  end
+  class UDPSocket
+    alias_method :orig_peeraddr, :peeraddr
+    include JRubyBug2558SocketPeerAddrBugFix
+  end
+end

lib/logstash/runner.rb

@@ -45,6 +45,7 @@ if ENV["PROFILE_BAD_LOG_CALLS"] || $DEBUGLIST.include?("log")
   end
 end # PROFILE_BAD_LOG_CALLS
 
+require "logstash/monkeypatches-for-bugs"
 require "logstash/monkeypatches-for-debugging"
 require "logstash/namespace"
 require "logstash/program"