Merge branch '339097-fix-discussions-access-cache' into 'master'

Fix stale MR discussion cache when author role changes

See merge request gitlab-org/gitlab!69642

app/models/note.rb

@@ -583,6 +583,7 @@ class Note < ApplicationRecord
 
   def post_processed_cache_key
     cache_key_items = [cache_key, author&.cache_key]
+    cache_key_items << project.team.human_max_access(author&.id) if author.present?
     cache_key_items << Digest::SHA1.hexdigest(redacted_note_html) if redacted_note_html.present?
 
     cache_key_items.join(':')

spec/models/note_spec.rb

@@ -1573,7 +1573,7 @@ RSpec.describe Note do
     let(:note) { build(:note) }
 
     it 'returns cache key and author cache key by default' do
-      expect(note.post_processed_cache_key).to eq("#{note.cache_key}:#{note.author.cache_key}")
+      expect(note.post_processed_cache_key).to eq("#{note.cache_key}:#{note.author.cache_key}:#{note.project.team.human_max_access(note.author_id)}")
     end
 
     context 'when note has no author' do
@@ -1592,7 +1592,7 @@ RSpec.describe Note do
       end
 
       it 'returns cache key with redacted_note_html sha' do
-        expect(note.post_processed_cache_key).to eq("#{note.cache_key}:#{note.author.cache_key}:#{Digest::SHA1.hexdigest(redacted_note_html)}")
+        expect(note.post_processed_cache_key).to eq("#{note.cache_key}:#{note.author.cache_key}:#{note.project.team.human_max_access(note.author_id)}:#{Digest::SHA1.hexdigest(redacted_note_html)}")
       end
     end
   end

spec/requests/projects/merge_requests_discussions_spec.rb

@@ -59,6 +59,7 @@ RSpec.describe 'merge requests discussions' do
       let!(:first_note) { create(:diff_note_on_merge_request, author: author, noteable: merge_request, project: project, note: "reference: #{reference.to_reference}") }
       let!(:second_note) { create(:diff_note_on_merge_request, in_reply_to: first_note, noteable: merge_request, project: project) }
       let!(:award_emoji) { create(:award_emoji, awardable: first_note) }
+      let!(:author_membership) { project.add_maintainer(author) }
 
       before do
         # Make a request to cache the discussions
@@ -229,6 +230,16 @@ RSpec.describe 'merge requests discussions' do
         end
       end
 
+      context 'when author role changes' do
+        before do
+          Members::UpdateService.new(user, access_level: Gitlab::Access::GUEST).execute(author_membership)
+        end
+
+        it_behaves_like 'cache miss' do
+          let(:changed_notes) { [first_note, second_note] }
+        end
+      end
+
       context 'when merge_request_discussion_cache is disabled' do
         before do
           stub_feature_flags(merge_request_discussion_cache: false)