Invalidate comparison cache when licenses approved or blacklisted

ee/app/models/software_license_policy.rb

@@ -43,4 +43,8 @@ class SoftwareLicensePolicy < ApplicationRecord
   end
 
   delegate :name, to: :software_license
+
+  def self.workaround_cache_key
+    pluck(:id, :approval_status).flatten
+  end
 end

ee/app/services/ci/compare_license_scanning_reports_service.rb

@@ -13,5 +13,11 @@ module Ci
     def get_report(pipeline)
       pipeline&.license_scanning_report
     end
+
+    private
+
+    def key(base_pipeline, head_pipeline)
+      super(base_pipeline, head_pipeline) + project.software_license_policies.workaround_cache_key
+    end
   end
 end

ee/spec/models/merge_request_spec.rb

@@ -453,6 +453,18 @@ describe MergeRequest do
           subject
         end
 
+        context 'cache key includes sofware license policies' do
+          let!(:license_1) { create(:software_license_policy, project: project) }
+          let!(:license_2) { create(:software_license_policy, project: project) }
+
+          it 'returns key with license information' do
+            expect_any_instance_of(Ci::CompareLicenseScanningReportsService)
+                .to receive(:execute).with(base_pipeline, head_pipeline).and_call_original
+
+            expect(subject[:key]).to include(*[license_1.id, license_1.approval_status, license_2.id, license_2.approval_status])
+          end
+        end
+
         context 'when cached results is not latest' do
           before do
             allow_any_instance_of(Ci::CompareLicenseScanningReportsService)