Provide deprecation on ProxyDepositListener

app/services/hyrax/listeners.rb

@@ -25,6 +25,7 @@ module Listeners
     autoload :MemberCleanupListener
     autoload :MetadataIndexListener
     autoload :ObjectLifecycleListener
+    autoload :ProxyDepositListener
     autoload :TrophyCleanupListener
     autoload :WorkflowListener
   end

app/services/hyrax/listeners/proxy_deposit_listener.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+module Hyrax
+  module Listeners
+    ##
+    # @deprecated transfer requests are now carried out synchronously during
+    # object save
+    #
+    ## Listens for deposit events, and checks for proxy situations. When a user
+    # deposits an item `on_behalf_of` another, ensures transfer is handled.
+    class ProxyDepositListener
+      ##
+      # Called when 'object.deposited' event is published
+      # @param [Dry::Events::Event] _event
+      # @return [void]
+      def on_object_deposited(_event)
+        Deprecation.warn(
+          "The ProxyDepositListener was deprecated, effective immediately, in \
+          response to a difficult-to-diagnose race condition bug. This listener \
+          is now a no-op. To retain functionality ensure that \
+          DefaultMiddlewareStack is configured to use \
+          Hyrax::Actors::TransferRequestActor. To quiet this deprecation remove any \
+          local initializer configuration that subscribes this listener."
+        )
+      end
+    end
+  end
+end

spec/services/hyrax/listeners/proxy_deposit_listener_spec.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+RSpec.describe Hyrax::Listeners::ProxyDepositListener do
+  subject(:listener) { described_class.new }
+  let(:data)         { { object: resource, user: depositor } }
+  let(:depositor)    { FactoryBot.create(:user) }
+  let(:event)        { Dry::Events::Event.new(event_type, data) }
+  let(:proxied_to)   { FactoryBot.create(:user) }
+  let(:resource)     { FactoryBot.valkyrie_create(:hyrax_work, on_behalf_of: proxied_to.user_key) }
+
+  describe 'on_object_deposited' do
+    let(:event_type) { :on_object_deposited }
+
+    context 'when object has been deposited as proxy for another user' do
+      it 'is a deprecated no-op' do
+        expect(Deprecation).to receive(:warn).at_least(:once)
+        expect { listener.on_object_deposited(event) }
+          .not_to have_enqueued_job
+      end
+    end
+  end
+end