Create a repository updated event when updating the default branch

ee/app/models/ee/repository.rb

@@ -78,6 +78,13 @@ module EE
       log_geo_updated_event
     end
 
+    override :after_change_head
+    def after_change_head
+      super
+    ensure
+      log_geo_updated_event
+    end
+
     def log_geo_updated_event
       return unless ::Gitlab::Geo.primary?
 

ee/app/services/geo/repository_sync_service.rb

@@ -6,7 +6,7 @@ module Geo
 
     def sync_repository
       fetch_repository
-      update_default_branch
+      update_root_ref
       mark_sync_as_successful
     rescue Gitlab::Shell::Error => e
       # In some cases repository does not exist, the only way to know about this is to parse the error text.
@@ -46,7 +46,7 @@ module Geo
     end
 
     # Update the default branch querying the remote to determine its HEAD
-    def update_default_branch
+    def update_root_ref
       root_ref = repository.find_remote_root_ref(GEO_REMOTE_NAME)
       project.change_head(root_ref) if root_ref.present?
     end

ee/spec/models/repository_spec.rb

@@ -3,8 +3,12 @@ require 'spec_helper'
 describe Repository do
   include RepoHelpers
   include ::EE::GeoHelpers
+
   TestBlob = Struct.new(:path)
 
+  set(:primary_node)   { create(:geo_node, :primary) }
+  set(:secondary_node) { create(:geo_node) }
+
   let(:project) { create(:project, :repository) }
   let(:repository) { project.repository }
 
@@ -116,8 +120,6 @@ describe Repository do
   end
 
   describe '#keep_around' do
-    set(:primary_node)   { create(:geo_node, :primary) }
-    set(:secondary_node) { create(:geo_node) }
     let(:sha) { sample_commit.id }
 
     context 'on a Geo primary' do
@@ -174,4 +176,20 @@ describe Repository do
       repository.code_owners_blob
     end
   end
+
+  describe '#after_change_head' do
+    it 'creates a RepositoryUpdatedEvent on a Geo primary' do
+      stub_current_geo_node(primary_node)
+
+      expect { repository.after_change_head }
+        .to change { ::Geo::RepositoryUpdatedEvent.count }.by(1)
+    end
+
+    it 'does not create a RepositoryUpdatedEvent on a Geo secondary' do
+      stub_current_geo_node(secondary_node)
+
+      expect { repository.after_change_head }
+        .not_to change { ::Geo::RepositoryUpdatedEvent.count }
+    end
+  end
 end