Add price sync logic to in-memory updater

This was introduced upstream in #6399 and we want to preserve this
functionality in the in-memory updater we're introducing as well.

Co-authored-by: Martin Meyerhoff <mamhoff@gmail.com>
Co-authored-by: Alistair Norman <alistair@super.gd>

Author: 3 people

core/app/models/spree/in_memory_order_updater.rb

@@ -33,6 +33,7 @@ def recalculate(persist: true)
 
       order.transaction do
         monitor.call do
+          recalculate_line_item_prices
           recalculate_item_count
           assign_shipment_amounts
         end
@@ -228,6 +229,12 @@ def recalculate_item_total
       recalculate_order_total
     end
 
+    def recalculate_line_item_prices
+      if Spree::Config.recalculate_cart_prices
+        line_items.each(&:recalculate_price)
+      end
+    end
+
     def persist_totals
       shipments.each(&:persist_amounts)
       assign_item_totals

core/spec/models/spree/in_memory_order_updater_spec.rb

@@ -350,6 +350,39 @@ module Spree
       end
     end
 
+    describe "price recalculation" do
+      let(:variant) { create(:variant, price: 98) }
+      let!(:order) { create(:order_with_line_items, line_items_attributes: [{ variant:, price: 98 }]) }
+
+      subject { updater.recalculate }
+
+      before do
+        variant.price = 100
+        variant.save!
+        order.reload
+      end
+
+      context "when recalculate_cart_prices is true" do
+        before do
+          stub_spree_preferences(recalculate_cart_prices: true)
+        end
+
+        it "sets prices to the currently active price" do
+          expect { subject }.to change { order.line_items.first.price }.from(98).to(100)
+        end
+      end
+
+      context "when recalculate_cart_prices is false" do
+        before do
+          stub_spree_preferences(recalculate_cart_prices: false)
+        end
+
+        it "does not recalculate prices" do
+          expect { subject }.not_to change { order.line_items.first.price }.from(98)
+        end
+      end
+    end
+
     context "updating shipment state" do
       let(:order) { create :order_with_line_items }