the typecast value should be passed to the serializer. fixes #10830

activerecord/lib/active_record/attribute_methods/serialization.rb

@@ -63,7 +63,7 @@ def initialize(column)
         end
 
         def type_cast(value)
-          value.unserialized_value
+          value.unserialized_value @column.type_cast value.value
         end
 
         def type
@@ -72,17 +72,17 @@ def type
       end
 
       class Attribute < Struct.new(:coder, :value, :state) # :nodoc:
-        def unserialized_value
-          state == :serialized ? unserialize : value
+        def unserialized_value(v = value)
+          state == :serialized ? unserialize(v) : value
         end
 
         def serialized_value
           state == :unserialized ? serialize : value
         end
 
-        def unserialize
+        def unserialize(v)
           self.state = :unserialized
-          self.value = coder.load(value)
+          self.value = coder.load(v)
         end
 
         def serialize

activerecord/test/cases/adapters/postgresql/bytea_test.rb

@@ -92,7 +92,6 @@ def dump(str); str; end
   end
 
   def test_serialize
-    serializer = Serializer.new
     klass = Class.new(ByteaDataType) {
       serialize :serialized, Serializer.new
     }