Improve documentation and fail on Windows

Author: elyscape

lib/puppet/parser/functions/pw_hash.rb

@@ -32,11 +32,18 @@
     password = args[0].to_s
     return nil if password.empty?
 
-    # work around JRuby bug in String#crypt for JRuby < 1.7.17
-    if RUBY_PLATFORM == 'java' and 'test'.crypt('$1$1') != '$1$1$Bp8CU9Oujr9SSEw53WV6G.'
-      def password.crypt(salt)
-        # puppetserver bundles Apache Commons Codec
-        org.apache.commons.codec.digest.Crypt.crypt(self.to_java_bytes, salt)
+    # handle weak implementations of String#crypt
+    if 'test'.crypt('$1$1') != '$1$1$Bp8CU9Oujr9SSEw53WV6G.'
+      # JRuby < 1.7.17
+      if RUBY_PLATFORM == 'java'
+        # override String#crypt for password variable
+        def password.crypt(salt)
+          # puppetserver bundles Apache Commons Codec
+          org.apache.commons.codec.digest.Crypt.crypt(self.to_java_bytes, salt)
+        end
+      else
+        # MS Windows and other systems that don't support enhanced salts
+        raise Puppet::ParseError, 'system does not support enhanced salts'
       end
     end
     password.crypt("$#{args[1]}$#{args[2]}")