Make `_before_type_cast` actually be before type cast

- The following is now true for all types, all the time
  - `model.attribute_before_type_cast == given_value`
  - `model.attribute == model.save_and_reload.attribute`
  - `model.attribute == model.dup.attribute`
  - `model.attribute == YAML.load(YAML.dump(model)).attribute`
- Removes the remaining types implementing `type_cast_for_write`
- Simplifies the implementation of time zone aware attributes
- Brings tz aware attributes closer to being implemented as an attribute
  decorator
- Adds additional point of control for custom types

3 files changed, 11 insertions, 3 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/column.rb b/activerecord/lib/active_record/connection_adapters/column.rb
index 23434df1fe..22decbc2da 100644
--- a/activerecord/lib/active_record/connection_adapters/column.rb
+++ b/activerecord/lib/active_record/connection_adapters/column.rb
@@ -17,7 +17,7 @@ module ActiveRecord
 
       delegate :type, :precision, :scale, :limit, :klass, :accessor,
         :text?, :number?, :binary?, :serialized?, :changed?,
-        :type_cast, :type_cast_for_write, :type_cast_for_database,
+        :type_cast, :type_cast_from_user, :type_cast_for_database,
         :type_cast_for_schema,
         to: :cast_type
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
index a65ca83f77..0a48a14b06 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/hstore.rb
@@ -7,7 +7,11 @@ module ActiveRecord
             :hstore
           end
 
-          def type_cast_for_write(value)
+          def type_cast_from_user(value)
+            type_cast(type_cast_for_database(value))
+          end
+
+          def type_cast_for_database(value)
             ConnectionAdapters::PostgreSQLColumn.hstore_to_string(value)
           end
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/oid/json.rb b/activerecord/lib/active_record/connection_adapters/postgresql/oid/json.rb
index c87422fe32..c64cf27797 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/oid/json.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/oid/json.rb
@@ -7,7 +7,11 @@ module ActiveRecord
             :json
           end
 
-          def type_cast_for_write(value)
+          def type_cast_from_user(value)
+            type_cast(type_cast_for_database(value))
+          end
+
+          def type_cast_for_database(value)
             ConnectionAdapters::PostgreSQLColumn.json_to_string(value)
           end