lib/attr/gather/workflow/callable.rb in attr-gather-1.4.0 vs lib/attr/gather/workflow/callable.rb in attr-gather-1.5.1

@@ -1,7 +1,9 @@
 # frozen_string_literal: true
 
+require 'concurrent/promise'
+
 module Attr
   module Gather
     module Workflow
       # @api private
       module Callable
@@ -61,10 +63,10 @@
         # @api private
         def aggregator
           return @aggregator if defined?(@aggregator) && !@aggregator.nil?
 
           @aggregator = self.class.aggregator
-          @aggregator.filter ||= filter
+          @aggregator.filter ||= filter if @aggregator.respond_to?(:filter=)
 
           @aggregator
         end
 
         # @api private