Clone links when cloning product variants

Only links within the same product are supported so far.

lib/spree/core/product_duplicator.rb

@@ -32,9 +32,12 @@ module Spree
       end
 
       def duplicate_variants
-        product.variants.map do |variant|
+        # Create a hash with mapping: { <orig-variant>: <new-variant>, }
+        mapped_variants = product.variants.index_with do |variant|
           duplicate_variant(variant)
         end
+        duplicate_variant_links(mapped_variants)
+        mapped_variants.values
       end
 
       def duplicate_variant(variant)
@@ -47,6 +50,19 @@ module Spree
         end
       end
 
+      def duplicate_variant_links(mapped_variants)
+        # Find any links between orig variants (links to/from another product are ignored)
+        variant_links = VariantLink.where(source_variant: [mapped_variants.keys],
+                                          target_variant: [mapped_variants.keys])
+        # Link the new variants
+        variant_links.find_each do |variant_link|
+          VariantLink.create(
+            source_variant: mapped_variants[variant_link.source_variant],
+            target_variant: mapped_variants[variant_link.target_variant]
+          )
+        end
+      end
+
       def duplicate_image(image)
         new_image = image.dup
         new_image.attachment.attach(image.attachment_blob)

spec/lib/spree/core/product_duplicator_spec.rb

@@ -36,6 +36,7 @@ RSpec.describe Spree::Core::ProductDuplicator do
 
     it "can duplicate a product" do
       duplicator = Spree::Core::ProductDuplicator.new(product)
+      allow(duplicator).to receive(:duplicate_variant_links) # tested elsewhere
       expect(new_product).to receive(:name=).with("COPY OF foo")
       expect(new_product).to receive(:sku=).with("")
       expect(new_product).to receive(:product_properties=).with([new_property])
@@ -65,6 +66,29 @@ RSpec.describe Spree::Core::ProductDuplicator do
     end
   end
 
+  describe "duplicating" do
+    subject { described_class.new(product).duplicate }
+    context "with variant links" do
+      let!(:product) { create(:product) }
+      let!(:source_variant) { product.variants.first }
+      let!(:linked_variant1) { source_variant.create_linked_variant(source_variant.supplier.owner) }
+      let!(:linked_variant2) { source_variant.create_linked_variant(source_variant.supplier.owner) }
+
+      it "duplicates variant links" do
+        expect(subject).to be_a Spree::Product
+        expect(subject.variants.count).to eq 3
+
+        # assuming they are cloned in the same order
+        new_source_variant = subject.variants[0]
+        new_linked_variant1 = subject.variants[1]
+        new_linked_variant2 = subject.variants[2]
+        expect(new_source_variant.target_variants).to eq [new_linked_variant1, new_linked_variant2]
+        expect(new_linked_variant1.source_variants).to eq [new_source_variant]
+        expect(new_linked_variant2.source_variants).to eq [new_source_variant]
+      end
+    end
+  end
+
   describe "errors" do
     context "with invalid product" do
       # Name has a max length of 255 char, when cloning a product the cloned product has a name