Don't query the database schema when calling `serialize`

We need to decorate the types lazily. This is extracted to a separate
API, as there are other refactorings that will be able to make use of
it, and to allow unit testing the finer points more granularly.

1 files changed, 11 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/column.rb b/activerecord/lib/active_record/connection_adapters/column.rb
index 5e4e00bc64..23434df1fe 100644
--- a/activerecord/lib/active_record/connection_adapters/column.rb
+++ b/activerecord/lib/active_record/connection_adapters/column.rb
@@ -13,7 +13,7 @@ module ActiveRecord
         ISO_DATETIME = /\A(\d{4})-(\d\d)-(\d\d) (\d\d):(\d\d):(\d\d)(\.\d+)?\z/
       end
 
-      attr_reader :name, :default, :cast_type, :null, :sql_type, :default_function
+      attr_reader :name, :cast_type, :null, :sql_type, :default_function
 
       delegate :type, :precision, :scale, :limit, :klass, :accessor,
         :text?, :number?, :binary?, :serialized?, :changed?,
@@ -35,7 +35,7 @@ module ActiveRecord
         @cast_type        = cast_type
         @sql_type         = sql_type
         @null             = null
-        @default          = extract_default(default)
+        @original_default = default
         @default_function = nil
       end
 
@@ -51,8 +51,15 @@ module ActiveRecord
         Base.human_attribute_name(@name)
       end
 
-      def extract_default(default)
-        type_cast(default)
+      def default
+        @default ||= type_cast(@original_default)
+      end
+
+      def with_type(type)
+        dup.tap do |clone|
+          clone.instance_variable_set('@default', nil)
+          clone.instance_variable_set('@cast_type', type)
+        end
       end
     end