Load names from line item where available.

I'm not sure why Arel complained about SQL in the SELECT clause (fields), but not the GROUP BY clause (key_fields). Maybe because it's not susceptible to user injection.

I'm also not sure why I couldn't use the aliases defined in SELECT in the GROUP BY clause, but hey this seems to work.

engines/dfc_provider/app/services/affiliate_sales_query.rb

@@ -14,7 +14,7 @@ class AffiliateSalesQuery
           },
         )
         .group(key_fields)
-        .pluck(fields)
+        .pluck(Arel.sql(fields))
     end
 
     # Create a hash with labels for an array of data points:
@@ -48,8 +48,8 @@ class AffiliateSalesQuery
 
     def fields
       <<~SQL.squish
-        spree_products.name AS product_name,
-        spree_variants.display_name AS unit_name,
+        COALESCE(spree_line_items.product_name, spree_products.name) AS product_name,
+        COALESCE(spree_line_items.variant_name, spree_variants.display_name) AS unit_name,
         spree_variants.variant_unit AS unit_type,
         spree_variants.unit_value AS units,
         spree_variants.unit_presentation,
@@ -65,8 +65,8 @@ class AffiliateSalesQuery
 
     def key_fields
       <<~SQL.squish
-        product_name,
-        unit_name,
+        COALESCE(spree_line_items.product_name, spree_products.name),
+        COALESCE(spree_line_items.variant_name, spree_variants.display_name),
         unit_type,
         units,
         spree_variants.unit_presentation,

engines/dfc_provider/spec/services/affiliate_sales_query_spec.rb

@@ -63,7 +63,7 @@ RSpec.describe AffiliateSalesQuery do
 
       expect(labelled_row).to include(
         product_name: "Tomatoes",
-        unit_name: "Tomatoes - Roma",
+        unit_name: "Tomatoes - Roma (1kg)",
         unit_type: "weight",
         units: 1000.to_f,
         unit_presentation: "1kg",
@@ -78,20 +78,22 @@ RSpec.describe AffiliateSalesQuery do
 
     it "returns data stored in line item at time of order" do
       # Records are updated after the orders are created
-      product.update! name: "Tomatoes Updated"
-      variant1.update! display_name: "Tomatoes - Updated Roma", price: 11
+      product.update! name: "Tommy toes"
+      variant1.update! display_name: "Tommy toes - Roma", price: 11
 
       labelled_row = query.label_row(query.data(order1.distributor).first)
 
-      pending "#13220 store product and variant names"
       expect(labelled_row).to include(
         product_name: "Tomatoes",
-        unit_name: "Tomatoes - Roma",
+        unit_name: "Tomatoes - Roma (1kg)",
         price: 10.to_d, # this price is hardcoded in the line item factory.
       )
     end
 
     it "returns data from variant if line item doesn't have it" do
+      # Old line item records (before migration 20250713110052) don't have these values stored
+      order1.line_items.first.update! product_name: nil, variant_name: nil
+
       labelled_row = query.label_row(query.data(order1.distributor).first)
 
       expect(labelled_row).to include(
@@ -131,12 +133,12 @@ RSpec.describe AffiliateSalesQuery do
 
           expect(labelled_data).to include a_hash_including(
             product_name: "Tomatoes",
-            unit_name: "Tomatoes - Roma",
+            unit_name: "Tomatoes - Roma (1kg)",
             quantity_sold: 1,
           )
           expect(labelled_data).to include a_hash_including(
             product_name: "Tomatoes",
-            unit_name: "Tomatoes - Cherry",
+            unit_name: "Tomatoes - Cherry (500g)",
             quantity_sold: 1,
             units: 500,
             unit_presentation: "500g",