Add migration to remove broken variants from open carts

db/migrate/20190906165501_remove_broken_variants_from_carts.rb

@@ -0,0 +1,17 @@
+class RemoveBrokenVariantsFromCarts < ActiveRecord::Migration
+  def up
+    # Removes line_items from open carts where the variant has a hard-deleted price
+
+    variants_without_prices = execute(
+      'SELECT spree_variants.id FROM spree_variants
+      LEFT OUTER JOIN spree_prices ON (spree_variants.id = spree_prices.variant_id)
+      WHERE spree_prices.id IS NULL'
+    ).to_a.map{ |v| v['id'] }
+
+    broken_line_items = Spree::LineItem.
+      joins(:variant).where('spree_variants.id IN (?)', variants_without_prices).
+      joins(:order).merge(Spree::Order.where(state: 'cart'))
+
+    broken_line_items.each(&:destroy)
+  end
+end