Fix duplication issue

When a product had mutiple variant assigned to the same category it
should only return the product one

app/reflexes/products_reflex.rb

@@ -152,7 +152,7 @@ class ProductsReflex < ApplicationReflex
 
   def fetch_products
     product_query = OpenFoodNetwork::Permissions.new(current_user)
-      .editable_products.merge(product_scope).ransack(ransack_query).result
+      .editable_products.merge(product_scope).ransack(ransack_query).result(distinct: true)
     @pagy, @products = pagy(product_query.order(:name), items: @per_page, page: @page,
                                                         size: [1, 2, 2, 1])
   end

spec/reflexes/products_reflex_spec.rb

@@ -15,7 +15,7 @@ describe ProductsReflex, type: :reflex, feature: :admin_style_v3 do
   end
 
   describe '#fetch' do
-    subject{ build_reflex(method_name: :fetch, **context) }
+    subject { build_reflex(method_name: :fetch, **context) }
 
     describe "sorting" do
       let!(:product_z) { create(:simple_product, name: "Zucchini") }
@@ -34,6 +34,27 @@ describe ProductsReflex, type: :reflex, feature: :admin_style_v3 do
     end
   end
 
+  describe '#filter' do
+    context "when filtering by category" do
+      let!(:product_a) { create(:simple_product, name: "Apples") }
+      let!(:product_z) do
+        create(:simple_product, name: "Zucchini").tap do |p|
+          p.variants.first.update(primary_taxon: category_c)
+        end
+      end
+      let(:category_c) { create(:taxon, name: "Category 1") }
+
+      it "returns product with a variant matching the given category" do
+        # Add a second variant to test we are not returning duplicate product
+        product_z.variants << create(:variant, primary_taxon: category_c)
+
+        reflex = run_reflex(:filter, params: { category_id: category_c.id } )
+
+        expect(reflex.get(:products).to_a).to eq([product_z])
+      end
+    end
+  end
+
   describe '#bulk_update' do
     let!(:variant_a1) {
       product_a.variants.first.tap{ |v|