Merge branch 'sh-optimize-groups-api' into 'master'

Optimize API /groups/:id/projects by preloading assocations

Closes #40308

See merge request gitlab-org/gitlab-ce!15475

3 files changed, 25 insertions, 4 deletions

diff --git a/spec/models/project_spec.rb b/spec/models/project_spec.rb
index 34e160aa599..000d5b7126d 100644
--- a/spec/models/project_spec.rb
+++ b/spec/models/project_spec.rb
@@ -315,7 +315,6 @@ describe Project do
 
     it { is_expected.to delegate_method(:empty_repo?).to(:repository) }
     it { is_expected.to delegate_method(:members).to(:team).with_prefix(true) }
-    it { is_expected.to delegate_method(:count).to(:forks).with_prefix(true) }
     it { is_expected.to delegate_method(:name).to(:owner).with_prefix(true).with_arguments(allow_nil: true) }
   end
 
@@ -2472,7 +2471,7 @@ describe Project do
     it 'returns the number of forks' do
       project = build(:project)
 
-      allow(project.forks).to receive(:count).and_return(1)
+      expect_any_instance_of(Projects::ForksCountService).to receive(:count).and_return(1)
 
       expect(project.forks_count).to eq(1)
     end
diff --git a/spec/requests/api/groups_spec.rb b/spec/requests/api/groups_spec.rb
index 04a658cd6c3..554723d6b1e 100644
--- a/spec/requests/api/groups_spec.rb
+++ b/spec/requests/api/groups_spec.rb
@@ -401,6 +401,20 @@ describe API::Groups do
 
         expect(response).to have_gitlab_http_status(404)
       end
+
+      it 'avoids N+1 queries' do
+        get api("/groups/#{group1.id}/projects", admin)
+
+        control_count = ActiveRecord::QueryRecorder.new do
+          get api("/groups/#{group1.id}/projects", admin)
+        end.count
+
+        create(:project, namespace: group1)
+
+        expect do
+          get api("/groups/#{group1.id}/projects", admin)
+        end.not_to exceed_query_limit(control_count)
+      end
     end
 
     context 'when using group path in URL' do
diff --git a/spec/services/projects/count_service_spec.rb b/spec/services/projects/count_service_spec.rb
index cc496501bad..183f6128c7b 100644
--- a/spec/services/projects/count_service_spec.rb
+++ b/spec/services/projects/count_service_spec.rb
@@ -4,9 +4,17 @@ describe Projects::CountService do
   let(:project) { build(:project, id: 1) }
   let(:service) { described_class.new(project) }
 
-  describe '#relation_for_count' do
+  describe '.query' do
     it 'raises NotImplementedError' do
-      expect { service.relation_for_count }.to raise_error(NotImplementedError)
+      expect { described_class.query(project.id) }.to raise_error(NotImplementedError)
+    end
+  end
+
+  describe '#relation_for_count' do
+    it 'calls the class method query with the project id' do
+      expect(described_class).to receive(:query).with(project.id)
+
+      service.relation_for_count
     end
   end