Merge branch '119333-systemstackerror-stack-level-too-deep' into 'master'

Prevent stack overflowing with a lot of user references

Closes #119333

See merge request gitlab-org/gitlab!22247

lib/banzai/reference_parser/base_parser.rb

@@ -177,7 +177,7 @@ module Banzai
             collection.where(id: to_query).each { |row| cache[row.id] = row }
           end
 
-          cache.values_at(*ids).compact
+          ids.uniq.map { |id| cache[id] }.compact
         else
           collection.where(id: ids)
         end

spec/lib/banzai/reference_parser/base_parser_spec.rb

@@ -312,6 +312,12 @@ describe Banzai::ReferenceParser::BaseParser do
         expect(subject.collection_objects_for_ids(Project, [project.id]))
           .to eq([project])
       end
+
+      it 'will not overflow the stack' do
+        ids = 1.upto(1_000_000).to_a
+
+        expect { subject.collection_objects_for_ids(User, ids) }.not_to raise_error
+      end
     end
   end