Merge pull request #5710 from nhsuk/fix-mmrv-memoisation-leak-in-offline-exporter

Fix memoisation leak between MMR and MMRV variants

Author: jhenderson

app/lib/reports/offline_session_exporter.rb

@@ -334,7 +334,7 @@ def add_existing_row_cells(row, vaccination_record:)
     row[:programme] = programme.import_names.first
     row[:vaccine_given] = Cell.new(
       vaccine&.upload_name,
-      allowed_values: vaccine_values_for_programmes([programme])
+      allowed_values: vaccine_values_for_programme(programme)
     )
     row[:performing_professional_email] = Cell.new(
       vaccination_record.performed_by_user&.email,
@@ -390,7 +390,7 @@ def add_new_row_cells(row, patient:, programme:)
     )
     row[:programme] = programme_variant.import_names.first
     row[:vaccine_given] = Cell.new(
-      allowed_values: vaccine_values_for_programmes([programme_variant])
+      allowed_values: vaccine_values_for_programme(programme_variant)
     )
     row[:performing_professional_email] = Cell.new(
       allowed_formula: performing_professionals_range
@@ -415,10 +415,15 @@ def add_new_row_cells(row, patient:, programme:)
     end
   end
 
-  def vaccine_values_for_programmes(programmes)
-    @vaccines[programmes] ||= Vaccine
+  def vaccine_values_for_programme(programme)
+    # We use the variant_type or type strings as the cache key because
+    # Programme::Variant delegates identity methods (hash, ==) to the base
+    # Programme. Without this, MMR vaccines would be returned for an MMRV
+    # variant.
+    cache_key = programme.try(:variant_type) || programme.type
+    @vaccines[cache_key] ||= Vaccine
       .active
-      .for_programmes(programmes)
+      .for_programmes([programme])
       .pluck(:upload_name)
   end
 

spec/lib/reports/offline_session_exporter_spec.rb

@@ -1189,4 +1189,27 @@ def validation_formula(worksheet:, column_name:, row: 1)
 
     include_examples "generates a report"
   end
+
+  describe "#vaccine_values_for_programmes" do
+    let(:programme) { Programme.mmr }
+    let(:mmr_programme_variant) do
+      Programme::Variant.new(programme, variant_type: "mmr")
+    end
+    let(:mmrv_programme_variant) do
+      Programme::Variant.new(programme, variant_type: "mmrv")
+    end
+    let(:session) { create(:session, programmes: [programme]) }
+
+    it "returns the correct vaccines for the given programme variants" do
+      exporter = described_class.send(:new, session)
+
+      expect(
+        exporter.send(:vaccine_values_for_programme, mmr_programme_variant)
+      ).to eq(%w[Priorix VaxPro])
+
+      expect(
+        exporter.send(:vaccine_values_for_programme, mmrv_programme_variant)
+      ).to eq(%w[ProQuad Priorix-Tetra])
+    end
+  end
 end