Ensure the type caster object given to Arel is always marshallable

The Relation will ultimately end up holding a reference to the arel
table object, and its associated type caster. If this is a
`TypeCaster::Connection`, that means it'll hold a reference to the
connection adapter, which cannot be marshalled. We can work around this
by just holding onto the class object instead. It's ugly, but I'm hoping
to remove the need for the connection adapter type caster in the future
anyway.

[Sean Griffin & anthonynavarre]

1 files changed, 4 insertions, 3 deletions

diff --git a/activerecord/lib/active_record/type_caster/connection.rb b/activerecord/lib/active_record/type_caster/connection.rb
index 9e4a130b40..1d204edb76 100644
--- a/activerecord/lib/active_record/type_caster/connection.rb
+++ b/activerecord/lib/active_record/type_caster/connection.rb
@@ -1,8 +1,8 @@
 module ActiveRecord
   module TypeCaster
     class Connection
-      def initialize(connection, table_name)
-        @connection = connection
+      def initialize(klass, table_name)
+        @klass = klass
         @table_name = table_name
       end
 
@@ -14,7 +14,8 @@ module ActiveRecord
 
       protected
 
-      attr_reader :connection, :table_name
+      attr_reader :table_name
+      delegate :connection, to: :@klass
 
       private