lib/paper_trail/serializers/yaml.rb in paper_trail-4.2.0 vs lib/paper_trail/serializers/yaml.rb in paper_trail-5.0.0

@@ -1,9 +1,10 @@
-require 'yaml'
+require "yaml"
 
 module PaperTrail
   module Serializers
+    # The default serializer for, e.g. `versions.object`.
     module YAML
       extend self # makes all instance methods become module methods as well
 
       def load(string)
         ::YAML.load string
@@ -21,16 +22,34 @@
 
       # Returns a SQL condition to be used to match the given field and value
       # in the serialized object_changes
       def where_object_changes_condition(arel_field, field, value)
         # Need to check first (before) and secondary (after) fields
-        if (defined?(::YAML::ENGINE) && ::YAML::ENGINE.yamler == 'psych') ||
-          (defined?(::Psych) && ::YAML == ::Psych)
-          arel_field.matches("%\n#{field}:\n- #{value}\n%").
-            or(arel_field.matches("%\n#{field}:\n-%\n- #{value}\n%"))
-        else # Syck adds extra spaces into array dumps
-          arel_field.matches("%\n#{field}: \n%- #{value}\n%").
-            or(arel_field.matches("%\n#{field}: \n-%\n- #{value}\n%"))
+        m1 = nil
+        m2 = nil
+        case yaml_engine_id
+        when :psych
+          m1 = "%\n#{field}:\n- #{value}\n%"
+          m2 = "%\n#{field}:\n-%\n- #{value}\n%"
+        when :syck
+          # Syck adds extra spaces into array dumps
+          m1 = "%\n#{field}: \n%- #{value}\n%"
+          m2 = "%\n#{field}: \n-%\n- #{value}\n%"
+        else
+          raise "Unknown yaml engine"
+        end
+        arel_field.matches(m1).or(arel_field.matches(m2))
+      end
+
+      # Returns a symbol identifying the YAML engine. Syck was removed from
+      # the ruby stdlib in ruby 2.0, but is still available as a gem.
+      # @api private
+      def yaml_engine_id
+        if (defined?(::YAML::ENGINE) && ::YAML::ENGINE.yamler == "psych") ||
+            (defined?(::Psych) && ::YAML == ::Psych)
+          :psych
+        else
+          :syck
         end
       end
     end
   end
 end