Use constants instead of variables and assign value when the module f…

…ile is loaded

lib/goldiloader/compatibility.rb

@@ -3,19 +3,20 @@
 module Goldiloader
   module Compatibility
 
+    MASS_ASSIGNMENT_SECURITY = (::ActiveRecord::VERSION::MAJOR < 4 || defined?(::ActiveRecord::MassAssignmentSecurity))
+    ASSOCIATION_FINDER_SQL = (::Gem::Version.new(::ActiveRecord::VERSION::STRING) < ::Gem::Version.new('4.1'))
+    UNSCOPE_QUERY_METHOD = (::Gem::Version.new(::ActiveRecord::VERSION::STRING) >= ::Gem::Version.new('4.1'))
+
     def self.mass_assignment_security_enabled?
-      @mass_assignment_security_enabled = (::ActiveRecord::VERSION::MAJOR < 4 || defined?(::ActiveRecord::MassAssignmentSecurity)) unless defined?(@mass_assignment_security_enabled)
-      @mass_assignment_security_enabled
+      MASS_ASSIGNMENT_SECURITY
     end
 
     def self.association_finder_sql_enabled?
-      @association_finder_sql = (::Gem::Version.new(::ActiveRecord::VERSION::STRING) < ::Gem::Version.new('4.1')) unless defined?(@association_finder_sql)
-      @association_finder_sql
+      ASSOCIATION_FINDER_SQL
     end
 
     def self.unscope_query_method_enabled?
-      @unscope_query_method = (::Gem::Version.new(::ActiveRecord::VERSION::STRING) >= ::Gem::Version.new('4.1')) unless defined?(@unscope_query_method)
-      @unscope_query_method
+      UNSCOPE_QUERY_METHOD
     end
   end
 end