Introduce an Attribute object to handle the type casting dance

There's a lot more that can be moved to these, but this felt like a good
place to introduce the object. Plans are:

- Remove all knowledge of type casting from the columns, beyond a
  reference to the cast_type
- Move type_cast_for_database to these objects
- Potentially make them mutable, introduce a state machine, and have
  dirty checking handled here as well
- Move `attribute`, `decorate_attribute`, and anything else that
  modifies types to mess with this object, not the columns hash
- Introduce a collection object to manage these, reduce allocations, and
  not require serializing the types

1 files changed, 3 insertions, 2 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/bytea.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bytea.rb
index 36c53d8732..89b203d2b1 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/bytea.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/bytea.rb
@@ -3,8 +3,9 @@ module ActiveRecord
     module PostgreSQL
       module OID # :nodoc:
         class Bytea < Type::Binary
-          def cast_value(value)
-            PGconn.unescape_bytea value
+          def type_cast_from_database(value)
+            return if value.nil?
+            PGconn.unescape_bytea(super)
           end
         end
       end