Fix pages build locking problem

atomic processing changes the lock_version of jobs, so it can cause
StaleObjectError in some places

app/services/projects/update_pages_service.rb

@@ -2,6 +2,8 @@
 
 module Projects
   class UpdatePagesService < BaseService
+    include Gitlab::OptimisticLocking
+
     InvalidStateError = Class.new(StandardError)
     FailedToExtractError = Class.new(StandardError)
 
@@ -23,8 +25,8 @@ module Projects
 
       # Create status notifying the deployment of pages
       @status = create_status
-      @status.enqueue!
-      @status.run!
+      retry_optimistic_lock(@status, &:enqueue!)
+      retry_optimistic_lock(@status, &:run!)
 
       raise InvalidStateError, 'missing pages artifacts' unless build.artifacts?
       raise InvalidStateError, 'build SHA is outdated for this ref' unless latest?
@@ -51,7 +53,7 @@ module Projects
     private
 
     def success
-      @status.success
+      retry_optimistic_lock(@status, &:success)
       @project.mark_pages_as_deployed
       super
     end
@@ -61,7 +63,7 @@ module Projects
       log_error("Projects::UpdatePagesService: #{message}")
       @status.allow_failure = !latest?
       @status.description = message
-      @status.drop(:script_failure)
+      retry_optimistic_lock(@status) { |status| status.drop(:script_failure) }
       super
     end
 

lib/api/commit_statuses.rb

@@ -106,7 +106,7 @@ module API
             status.enqueue!
           when 'running'
             status.enqueue
-            status.run!
+            Gitlab::OptimisticLocking.retry_lock(status, &:run!)
           when 'success'
             status.success!
           when 'failed'

spec/services/projects/update_pages_service_spec.rb

@@ -158,6 +158,23 @@ describe Projects::UpdatePagesService do
           expect(project.pages_metadatum).not_to be_deployed
         end
       end
+
+      context 'with background jobs running', :sidekiq_inline do
+        where(:ci_atomic_processing) do
+          [true, false]
+        end
+
+        with_them do
+          before do
+            stub_feature_flags(ci_atomic_processing: ci_atomic_processing)
+          end
+
+          it 'succeeds' do
+            expect(project.pages_deployed?).to be_falsey
+            expect(execute).to eq(:success)
+          end
+        end
+      end
     end
   end