🎁 Change set_child_flag transaction to listener

This commit will remove the set_child_flag transaction and replace it
with a listener.

Ref:
  - #330

app/listeners/iiif_print/listener.rb

@@ -29,5 +29,21 @@ def on_file_set_attached(event, service: IiifPrint::SplitPdfs::ChildWorkCreation
 
       service.conditionally_enqueue(file_set: file_set, work: work, file: file, user: user)
     end
+
+    ##
+    # Responsible for setting the is_child flag on the work when a child work is created.
+    #
+    # @param event [#[]] a hash like construct with :object key
+    def on_object_membership_updated(event)
+      object = event[:object]
+      return unless object.respond_to?(:iiif_print_config?) && object.iiif_print_config?
+
+      Hyrax.custom_queries.find_child_works(resource: object).each do |child_work|
+        unless child_work.is_child
+          child_work.is_child = true
+          Hyrax.persister.save(resource: child_work)
+        end
+      end
+    end
   end
 end

app/transactions/hyrax/transactions/iiif_print_container_decorator.rb

@@ -27,34 +27,6 @@ class IiifPrintContainerDecorator
           )
         end
       end
-
-      namespace 'change_set' do |ops|
-        ops.register 'update_work' do
-          steps = Hyrax::Transactions::WorkUpdate::DEFAULT_STEPS.dup
-          # NOTE: applications that don't want the file splitting of IIIF Print will want to remove
-          # this step from their transactions.
-          steps.insert(steps.index('work_resource.update_work_members') + 1, 'work_resource.set_child_flag')
-          Hyrax::Transactions::WorkUpdate.new(steps: steps)
-        end
-      end
-
-      if defined?(Bulkrax::Transactions::Container)
-        namespace 'work_resource' do |ops|
-          ops.register Bulkrax::Transactions::Container::UPDATE_WITH_BULK_BEHAVIOR do
-            steps = Bulkrax::Transactions::Container::UPDATE_WITH_BULK_BEHAVIOR_STEPS.dup
-            # NOTE: applications that don't want the file splitting of IIIF Print will want to remove
-            # this step from their transactions.
-            steps.insert(steps.index('work_resource.update_work_members') + 1, 'work_resource.set_child_flag')
-            Hyrax::Transactions::WorkUpdate.new(steps: steps)
-          end
-        end
-      end
-
-      namespace 'work_resource' do |ops|
-        ops.register 'set_child_flag' do
-          Steps::SetChildFlag.new
-        end
-      end
     end
   end
 end

spec/listeners/iiif_print/listener_spec.rb

@@ -30,4 +30,38 @@
       end
     end
   end
+
+  describe '#on_object_membership_updated' do
+    class Work < Hyrax::Work
+      include Hyrax::Schema(:child_works_from_pdf_splitting)
+
+      def iiif_print_config?
+        true
+      end
+    end
+
+    subject { described_class.new.on_object_membership_updated(event) }
+
+    let(:event) { { object: parent_work } }
+    let(:parent_work) do
+      parent_work = Work.new
+      parent_work.title = ['Parent Work']
+      Hyrax.persister.save(resource: parent_work)
+    end
+    let(:child_work) do
+      child_work = Work.new
+      child_work.title = ['Child Work']
+      Hyrax.persister.save(resource: child_work)
+    end
+
+    before do
+      parent_work.member_ids << child_work.id
+      Hyrax.persister.save(resource: parent_work)
+      Hyrax.index_adapter.save(resource: parent_work)
+    end
+
+    it 'sets the is_child flag on the child work' do
+      expect { subject }.to change { Hyrax.query_service.find_by(id: child_work.id).is_child }.to(true)
+    end
+  end
 end

spec/transactions/hyrax/transactions/iiif_print_container_decorator_spec.rb

@@ -26,13 +26,7 @@
       expect(transaction_step.steps).to match_array(["change_set.apply",
                                                      "work_resource.save_acl",
                                                      "work_resource.add_file_sets",
-                                                     "work_resource.update_work_members",
-                                                     "work_resource.set_child_flag"])
+                                                     "work_resource.update_work_members"])
     end
   end
-
-  describe 'work_resource.set_child_flag' do
-    subject(:transaction_step) { described_class['work_resource.set_child_flag'] }
-    it { is_expected.to be_a Hyrax::Transactions::Steps::SetChildFlag }
-  end
 end