Only load project license if needed

https://gitlab.com/gitlab-org/gitlab/-/merge_requests/24310 introduced a
unintended side effect: instead of loading the project license name only
when the explore tab were present, the license would always be loaded
even if it were not displayed.

To fix that, we now load the license only if it is needed and memoize
the value via `SafeRequestStore` in the helper.

Closes https://gitlab.com/gitlab-org/gitlab/-/issues/223740

app/helpers/projects_helper.rb

@@ -384,9 +384,12 @@ module ProjectsHelper
   end
 
   def project_license_name(project)
-    project.repository.license&.name
+    key = "project:#{project.id}:license_name"
+
+    Gitlab::SafeRequestStore.fetch(key) { project.repository.license&.name }
   rescue GRPC::Unavailable, GRPC::DeadlineExceeded, Gitlab::Git::CommandError => e
     Gitlab::ErrorTracking.track_exception(e)
+    Gitlab::SafeRequestStore[key] = nil
 
     nil
   end

app/views/shared/projects/_project.html.haml

@@ -16,7 +16,6 @@
 - css_controls_class = compact_mode ? [] : ["flex-lg-row", "justify-content-lg-between"]
 - css_controls_class << "with-pipeline-status" if show_pipeline_status_icon
 - avatar_container_class = project.creator && use_creator_avatar ? '' : 'rect-avatar'
-- license_name = project_license_name(project)
 
 %li.project-row.d-flex{ class: css_class }
   = cache(cache_key) do
@@ -43,10 +42,10 @@
           %span.metadata-info.visibility-icon.append-right-10.gl-mt-3.text-secondary.has-tooltip{ data: { container: 'body', placement: 'top' }, title: visibility_icon_description(project) }
             = visibility_level_icon(project.visibility_level, fw: true)
 
-          - if explore_projects_tab? && license_name
+          - if explore_projects_tab? && project_license_name(project)
             %span.metadata-info.d-inline-flex.align-items-center.append-right-10.gl-mt-3
               = sprite_icon('scale', size: 14, css_class: 'append-right-4')
-              = license_name
+              = project_license_name(project)
 
           - if !explore_projects_tab? && access&.nonzero?
             -# haml-lint:disable UnnecessaryStringOutput

changelogs/unreleased/sh-memoize-project-license-name.yml

+---
+title: Only load project license if needed
+merge_request: 35068
+author:
+type: performance

spec/helpers/projects_helper_spec.rb

@@ -977,19 +977,32 @@ describe ProjectsHelper do
     end
   end
 
-  describe '#project_license_name(project)' do
+  describe '#project_license_name(project)', :request_store do
     let_it_be(:project) { create(:project) }
     let_it_be(:repository) { project.repository }
 
     subject { project_license_name(project) }
 
+    def license_name
+      project_license_name(project)
+    end
+
     context 'gitaly is working appropriately' do
-      it 'returns the license name' do
-        license = Licensee::License.new('mit')
-        allow(repository).to receive(:license).and_return(license)
+      let(:license) { Licensee::License.new('mit') }
+
+      before do
+        expect(repository).to receive(:license).and_return(license)
+      end
 
+      it 'returns the license name' do
         expect(subject).to eq(license.name)
       end
+
+      it 'memoizes the value' do
+        expect do
+          2.times { expect(license_name).to eq(license.name) }
+        end.to change { Gitlab::GitalyClient.get_request_count }.by_at_most(1)
+      end
     end
 
     context 'gitaly is unreachable' do
@@ -1003,10 +1016,16 @@ describe ProjectsHelper do
 
           subject
         end
+
+        it 'memoizes the nil value' do
+          expect do
+            2.times { expect(license_name).to be_nil }
+          end.to change { Gitlab::GitalyClient.get_request_count }.by_at_most(1)
+        end
       end
 
       before do
-        allow(repository).to receive(:license).and_raise(exception)
+        expect(repository).to receive(:license).and_raise(exception)
       end
 
       context "Gitlab::Git::CommandError" do