Remove a duplicate method and add the original monkey patched code a comment for ease of understanding the change

Author: Kyle d'Oliveira

lib/polymorphic_integer_type/extensions.rb

@@ -24,11 +24,6 @@ def belongs_to(name, scope = nil, **options)
             mapping
           end
 
-          # Required way to dynamically define a class method on the model
-          singleton_class.__send__(:define_method, "#{foreign_type}_mapping") do
-            mapping
-          end
-
           define_method foreign_type do
             t = super()
             mapping[t]

lib/polymorphic_integer_type/predicate_builder_extension.rb

@@ -1,5 +1,34 @@
 module PolymorphicIntegerType
   module PredicateBuilderExtension
+
+    # Original Code:
+    # def self.expand(klass, table, column, value)
+    #   queries = []
+
+    #   # Find the foreign key when using queries such as:
+    #   # Post.where(author: author)
+    #   #
+    #   # For polymorphic relationships, find the foreign key and type:
+    #   # PriceEstimate.where(estimate_of: treasure)
+    #   if klass && reflection = klass._reflect_on_association(column)
+    #     base_class = polymorphic_base_class_from_value(value)
+
+    #     if reflection.polymorphic? && base_class
+    #       queries << build(table[reflection.foreign_type], base_class)
+    #     end
+
+    #     column = reflection.foreign_key
+
+    #     if base_class
+    #       primary_key = reflection.association_primary_key(base_class)
+    #       value = convert_value_to_association_ids(value, primary_key)
+    #     end
+    #   end
+
+    #   queries << build(table[column], value)
+    #   queries
+    # end
+
     def expand(klass, table, column, value)
       queries = []
 

spec/spec_helper.rb

@@ -13,7 +13,9 @@
   config.before(:suite) do
     database_config = YAML.load(File.open("#{File.dirname(__FILE__)}/support/database.yml"))
     ActiveRecord::Base.establish_connection(database_config)
-    ActiveRecord::MigrationContext.new("#{File.dirname(__FILE__)}/support/migrations").migrate
+    if Gem::Version.new(ActiveRecord::VERSION::STRING) >= Gem::Version.new("5")
+      ActiveRecord::MigrationContext.new("#{File.dirname(__FILE__)}/support/migrations").migrate
+    end
   end
 
   config.around do |example|