1 files changed, 5 insertions, 12 deletions
diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
index 2f32caa257..b9b2acff37 100644
--- a/activerecord/lib/active_record/attribute_methods/primary_key.rb
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -8,17 +8,14 @@ module ActiveRecord
       # Returns this record's primary key value wrapped in an array if one is
       # available.
       def to_key
-        sync_with_transaction_state
         key = id
         [key] if key
       end
 
       # Returns the primary key value.
       def id
-        if pk = self.class.primary_key
-          sync_with_transaction_state
-          _read_attribute(pk)
-        end
+        sync_with_transaction_state
+        _read_attribute(self.class.primary_key) if self.class.primary_key
       end
 
       # Sets the primary key value.
@@ -57,16 +54,12 @@ module ActiveRecord
         end
 
         module ClassMethods
-          def define_method_attribute(attr_name)
-            super
+          ID_ATTRIBUTE_METHODS = %w(id id= id? id_before_type_cast id_was id_in_database).to_set
 
-            if attr_name == primary_key && attr_name != "id"
-              generated_attribute_methods.send(:alias_method, :id, primary_key)
-            end
+          def instance_method_already_implemented?(method_name)
+            super || primary_key && ID_ATTRIBUTE_METHODS.include?(method_name)
           end
 
-          ID_ATTRIBUTE_METHODS = %w(id id= id? id_before_type_cast id_was id_in_database).to_set
-
           def dangerous_attribute_method?(method_name)
             super && !ID_ATTRIBUTE_METHODS.include?(method_name)
           end