Fix N+1 in MergeRequestParser

read_project can be prevented by a very expensive condition, which we want to
avoid, while still not writing manual SQL queries. read_project_for_iids is used
by read_issue_iid and read_merge_request_iid to satisfy both of those
constraints, and allow the declarative policy runner to use its normal caching
strategy.

1 files changed, 23 insertions, 0 deletions

diff --git a/spec/lib/banzai/reference_parser/issue_parser_spec.rb b/spec/lib/banzai/reference_parser/issue_parser_spec.rb
index 0a63567ee40..cb7f8b20dda 100644
--- a/spec/lib/banzai/reference_parser/issue_parser_spec.rb
+++ b/spec/lib/banzai/reference_parser/issue_parser_spec.rb
@@ -117,4 +117,27 @@ describe Banzai::ReferenceParser::IssueParser do
       expect(subject.records_for_nodes(nodes)).to eq({ link => issue })
     end
   end
+
+  context 'when checking multiple merge requests on another project' do
+    let(:other_project) { create(:project, :public) }
+    let(:other_issue) { create(:issue, project: other_project) }
+
+    let(:control_links) do
+      [issue_link(other_issue)]
+    end
+
+    let(:actual_links) do
+      control_links + [issue_link(create(:issue, project: other_project))]
+    end
+
+    def issue_link(issue)
+      Nokogiri::HTML.fragment(%Q{<a data-issue="#{issue.id}"></a>}).children[0]
+    end
+
+    before do
+      project.add_developer(user)
+    end
+
+    it_behaves_like 'no N+1 queries'
+  end
 end