Republish drafts of other translations on PUT of new translation

When a draft translation is added and another translation of the same
content ID exists, we need to send the existing translation(s)
downstream so their `available_translations` links can be updated to
include the new translation.

We're not currently doing this, which leads to a situation where the
link to the new translation never appears on the draft of the existing
translations.

app/commands/v2/put_content.rb

@@ -4,6 +4,8 @@ class PutContent < BaseCommand
       def call
         PutContentValidator.new(payload, self).validate
 
+        update_draft_items_of_different_locale_but_matching_content_id
+
         remove_previous_path_reservations
         reserve_current_path
         clear_draft_items_of_same_locale_and_base_path
@@ -200,6 +202,29 @@ def clear_draft_item_of_different_locale_but_matching_base_path
         )
       end
 
+      def update_draft_items_of_different_locale_but_matching_content_id
+        return unless payload[:base_path]
+        return if Document.where(content_id: payload[:content_id], locale: payload[:locale]).any?
+
+        draft_editions_for_different_locale = Document
+          .where(content_id: payload[:content_id])
+          .where
+          .not(locale: payload[:locale])
+          .map(&:draft)
+          .compact
+
+        after_transaction_commit do
+          draft_editions_for_different_locale.each do |edition|
+            DownstreamDraftWorker.perform_async_in_queue(
+              bulk_publishing? ? DownstreamDraftWorker::LOW_QUEUE : DownstreamDraftWorker::HIGH_QUEUE,
+              "content_id" => edition.content_id,
+              "locale" => edition.locale,
+              "source_command" => "put_content",
+            )
+          end
+        end
+      end
+
       def bulk_publishing?
         payload.fetch(:bulk_publishing, false)
       end

spec/commands/v2/put_content_spec.rb

@@ -338,7 +338,7 @@
       end
     end
 
-    context "when a draft does exist with a different locale" do
+    context "when a draft does exist with a different locale but same base path" do
       let(:en_document) { create(:document, content_id:) }
       let!(:en_edition) do
         create(:draft_edition, base_path:, document: en_document)
@@ -387,5 +387,45 @@
         described_class.call(payload)
       end
     end
+
+    context "when creating a new translation and a draft exists with a different locale and different base path" do
+      let(:cy_document) { create(:document, content_id:, locale: "cy") }
+      let!(:cy_edition) do
+        create(:draft_edition, base_path: "#{base_path}.cy", document: cy_document)
+      end
+
+      it "sends all draft translations downstream" do
+        expect(DownstreamDraftWorker).to receive(:perform_async_in_queue)
+          .with(anything, a_hash_including("content_id" => content_id, "locale" => "en"))
+
+        expect(DownstreamDraftWorker).to receive(:perform_async_in_queue)
+          .with(anything, a_hash_including("content_id" => content_id, "locale" => "cy"))
+
+        described_class.call(payload)
+      end
+    end
+
+    context "when updating a translation and a draft exists with a different locale and different base path" do
+      let(:en_document) { create(:document, content_id:, locale: "en") }
+      let!(:en_edition) do
+        create(:draft_edition, base_path:, document: en_document)
+      end
+
+      let(:cy_document) { create(:document, content_id:, locale: "cy") }
+      let!(:cy_edition) do
+        create(:draft_edition, base_path: "#{base_path}.cy", document: cy_document)
+      end
+
+      it "sends only sends the updated translation downstream" do
+        expect(DownstreamDraftWorker).to receive(:perform_async_in_queue)
+          .with(anything, a_hash_including("content_id" => content_id, "locale" => "en"))
+
+        expect(DownstreamDraftWorker).to receive(:perform_async_in_queue)
+          .with(anything, a_hash_including("content_id" => content_id, "locale" => "cy"))
+          .never
+
+        described_class.call(payload)
+      end
+    end
   end
 end