Undefine id and let it automatically be generated

activerecord/lib/active_record/attribute_methods.rb

@@ -77,6 +77,9 @@ module ActiveRecord
             end
           end
         end
+        unless generated_methods.include?("id")
+          define_read_method(:id, primary_key, columns_hash[primary_key.to_s])
+        end
       end
 
       def undefine_attribute_methods
@@ -89,7 +92,6 @@ module ActiveRecord
       # method is defined by Active Record though.
       def instance_method_already_implemented?(method_name)
         method_name = method_name.to_s
-        return true if method_name == "id"
         @_defined_class_methods         ||= ancestors.first(ancestors.index(ActiveRecord::Base)).sum([]) { |m| m.public_instance_methods(false) | m.private_instance_methods(false) | m.protected_instance_methods(false) }.map {|m| m.to_s }.to_set
         @@_defined_activerecord_methods ||= (ActiveRecord::Base.public_instance_methods(false) | ActiveRecord::Base.private_instance_methods(false) | ActiveRecord::Base.protected_instance_methods(false)).map{|m| m.to_s }.to_set
         raise DangerousAttributeError, "#{method_name} is defined by ActiveRecord" if @@_defined_activerecord_methods.include?(method_name)
@@ -109,9 +111,7 @@ module ActiveRecord
 
         # Evaluate the definition for an attribute related method
         def evaluate_attribute_method(attr_name, method_definition, method_name)
-          unless method_name.to_s == primary_key.to_s
           generated_methods << method_name
-          end
 
           begin
             class_eval(method_definition, __FILE__, __LINE__)

activerecord/lib/active_record/attribute_methods/read.rb

@@ -5,6 +5,7 @@ module ActiveRecord
 
       included do
         attribute_method_suffix ""
+        undef_method :id
       end
 
       module ClassMethods
@@ -54,7 +55,7 @@ module ActiveRecord
             if cache_attribute?(attr_name)
               access_code = "@attributes_cache['#{attr_name}'] ||= (#{access_code})"
             end
-            evaluate_attribute_method attr_name, "def #{symbol}; #{access_code}; end", attr_name
+            evaluate_attribute_method attr_name, "def #{symbol}; #{access_code}; end", symbol
           end
       end
 
@@ -78,16 +79,6 @@ module ActiveRecord
         end
       end
 
-      # A model instance's primary key is always available as model.id
-      # whether you name it the default 'id' or set it to something else.
-      def id
-        attr_name = self.class.primary_key
-        column = column_for_attribute(attr_name)
-
-        self.class.send(:define_read_method, :id, attr_name, column)
-        id
-      end
-
       # Returns true if the attribute is of a text column and marked for serialization.
       def unserializable_attribute?(attr_name, column)
         column.text? && self.class.serialized_attributes[attr_name]

activerecord/test/cases/attribute_methods_test.rb

@@ -74,10 +74,6 @@ class AttributeMethodsTest < ActiveRecord::TestCase
     end
   end
 
-  def test_primary_key_implemented
-    assert Class.new(ActiveRecord::Base).instance_method_already_implemented?('id')
-  end
-
   def test_defined_kernel_methods_implemented_in_model
     %w(test name display y).each do |method|
       klass = Class.new ActiveRecord::Base

activerecord/test/cases/base_test.rb

@@ -422,11 +422,6 @@ class BasicsTest < ActiveRecord::TestCase
   end
 
 
-  def test_reader_for_invalid_column_names
-    Topic.send(:define_read_method, "mumub-jumbo".to_sym, "mumub-jumbo", nil)
-    assert !Topic.generated_methods.include?("mumub-jumbo")
-  end
-
   def test_non_attribute_access_and_assignment
     topic = Topic.new
     assert !topic.respond_to?("mumbo")