Support on_duplicate_key_update for recursive imports

lib/activerecord-import/import.rb

@@ -857,6 +857,15 @@ def import_without_validations_or_callbacks( column_names, array_of_attributes,
 
     private
 
+    def associated_options(options, associated_class)
+      return options unless options.key?(:recursive_on_duplicate_key_update)
+
+      table_name = associated_class.arel_table.name.to_sym
+      options.merge(
+        on_duplicate_key_update: options[:recursive_on_duplicate_key_update][table_name]
+      )
+    end
+
     def set_attributes_and_mark_clean(models, import_result, timestamps, options)
       return if models.nil?
       models -= import_result.failed_instances
@@ -963,7 +972,11 @@ def import_associations(models, options)
 
       associated_objects_by_class.each_value do |associations|
         associations.each_value do |associated_records|
-          associated_records.first.class.bulk_import(associated_records, options) unless associated_records.empty?
+          next if associated_records.empty?
+
+          associated_class = associated_records.first.class
+          associated_class.bulk_import(associated_records,
+                                       associated_options(options, associated_class))
         end
       end
     end

test/support/shared_examples/recursive_import.rb

@@ -213,6 +213,54 @@ def should_support_recursive_import
           end
         end
       end
+
+      describe "recursive_on_duplicate_key_update" do
+        let(:new_topics) { Build(1, :topic_with_book) }
+
+        setup do
+          Topic.import new_topics, recursive: true
+        end
+
+        it "updates associated objects" do
+          new_author_name = 'Richard Bachman'
+          topic = new_topics.first
+          topic.books.each do |book|
+            book.author_name = new_author_name
+          end
+
+          assert_nothing_raised do
+            Topic.import new_topics,
+              recursive: true,
+              on_duplicate_key_update: [:id],
+              recursive_on_duplicate_key_update: {
+                books: { conflict_target: [:id], columns: [:author_name] }
+              }
+          end
+          Topic.find(topic.id).books.each do |book|
+            assert_equal new_author_name, book.author_name
+          end
+        end
+
+        it "updates nested associated objects" do
+          new_chapter_title = 'The Final Chapter'
+          book = new_topics.first.books.first
+          book.author_name = 'Richard Bachman'
+
+          example_chapter = book.chapters.first
+          example_chapter.title = new_chapter_title
+
+          assert_nothing_raised do
+            Topic.import new_topics,
+              recursive: true,
+              on_duplicate_key_update: [:id],
+              recursive_on_duplicate_key_update: {
+                books: { conflict_target: [:id], columns: [:author_name] },
+                chapters: { conflict_target: [:id], columns: [:title] }
+              }
+          end
+          assert_equal new_chapter_title, Chapter.find(example_chapter.id).title
+        end
+      end
     end
 
     # If returning option is provided, it is only applied to top level models so that SQL with invalid