Handle nil results in NetworkPoliciesController#summary

ee/app/controllers/projects/security/network_policies_controller.rb

@@ -19,7 +19,7 @@ module Projects
           interval: params[:interval] || "minute",
           from:     (Time.parse(params[:from]) rescue 1.hour.ago),
           to:       (Time.parse(params[:to]) rescue Time.now)
-        )
+        ) || {}
 
         respond_to do |format|
           format.json do

ee/spec/controllers/projects/security/network_policies_controller_spec.rb

@@ -88,6 +88,15 @@ describe Projects::Security::NetworkPoliciesController do
             end
           end
         end
+
+        context 'with nil results' do
+          it 'returns network policies summary' do
+            allow(adapter).to receive(:query).and_return(nil)
+            subject
+
+            expect(response).to have_gitlab_http_status(:bad_request)
+          end
+        end
       end
 
       context 'without prometheus configured' do