class ActiveRecord::ConnectionAdapters::PostgreSQL::OID::Array

def cast(value)
  if value.is_a?(::String)
    value = begin
      @pg_decoder.decode(value)
    rescue TypeError
      # malformed array string is treated as [], will raise in PG 2.0 gem
      # this keeps a consistent implementation
      []
    end
  end
  type_cast_array(value, :cast)
end