config_loader.rb in rubocop-0.25.0

- old
+ new

@@ -1,17 +1,10 @@
 # encoding: utf-8
 
 require 'yaml'
 require 'pathname'
 
-# Psych can give an error when reading an empty file, so we use syck in Ruby
-# versions where it's available. Also, the problem with empty files does not
-# appear in Ruby 2 or in JRuby 1.9 mode.
-if RUBY_VERSION < '2.0.0' && RUBY_PLATFORM != 'java'
-  YAML::ENGINE.yamler = 'syck'
-end
-
 module RuboCop
   # This class represents the configuration of the RuboCop application
   # and all its cops. A Config is associated with a YAML configuration
   # file from which it was read. Several different Configs can be used
   # during a run of the rubocop program, if files in several
@@ -29,10 +22,21 @@
       alias_method :debug?, :debug
       alias_method :auto_gen_config?, :auto_gen_config
 
       def load_file(path)
         path = File.absolute_path(path)
+
+        # Psych can give an error when reading an empty file, so we use syck in
+        # Ruby versions where it's available. Also, the problem with empty
+        # files does not appear in Ruby 2 or in JRuby 1.9 mode.
+        if RUBY_VERSION < '2.0.0' && RUBY_PLATFORM != 'java'
+          original_yamler = YAML::ENGINE.yamler
+          YAML::ENGINE.yamler = 'syck'
+        end
         hash = YAML.load_file(path) || {}
+        # Restore yamler for applications using RuboCop as a library.
+        YAML::ENGINE.yamler = original_yamler if original_yamler
+
         puts "configuration from #{path}" if debug?
 
         resolve_inheritance(path, hash)
 
         Array(hash.delete('require')).each { |r| require(r) }