Make retry_lock to not be infinite

app/services/ci/process_pipeline_service.rb

@@ -31,8 +31,8 @@ module Ci
       if HasStatus::COMPLETED_STATUSES.include?(current_status)
         created_builds_in_stage(index).select do |build|
-          Gitlab::OptimisticLocking.retry_lock(build) do |build|
-            process_build(build, current_status)
+          Gitlab::OptimisticLocking.retry_lock(build) do |subject|
+            process_build(subject, current_status)
           end
         end
       end

lib/gitlab/optimistic_locking.rb

 module Gitlab
-  class OptimisticLocking
-    def self.retry_lock(subject, &block)
+  module OptimisticLocking
+    extend self
+
+    def retry_lock(subject, retries = 100, &block)
       loop do
         begin
-          subject.transaction do
+          ActiveRecord::Base.transaction do
             return block.call(subject)
           end
         rescue ActiveRecord::StaleObjectError
+          retries -= 1
+          raise unless retries >= 0
           subject.reload
         end
       end

spec/lib/gitlab/optimistic_locking_spec.rb

@@ -24,5 +24,16 @@ describe Gitlab::OptimisticLocking, lib: true do
         subject.drop
       end
     end
+
+    it 'raises exception when too many retries' do
+      expect(pipeline).to receive(:drop).twice.and_call_original
+
+      expect do
+        described_class.retry_lock(pipeline, 1) do |subject|
+          subject.lock_version = 100
+          subject.drop
+        end
+      end.to raise_error(ActiveRecord::StaleObjectError)
+    end
   end
 end