Migrate master variant :sku to product

(cherry picked from commit d8649fc9fb)

app/models/spree/product.rb

@@ -75,7 +75,7 @@ module Spree
         )
     }
 
-    delegate_belongs_to :master, :images, :sku
+    delegate_belongs_to :master, :images
     delegate :images_attributes=, to: :master
 
     # Transient attributes used temporarily when creating a new product,

db/migrate/20230522090252_add_sku_to_product.rb

@@ -0,0 +1,24 @@
+class AddSkuToProduct < ActiveRecord::Migration[7.0]
+  def up
+    add_column :spree_products, :sku, :string, limit: 255, default: "", null: false
+
+    migrate_master_sku
+  end
+
+  def down
+    remove_column :spree_products, :sku
+  end
+
+  private
+
+  def migrate_master_sku
+    ActiveRecord::Base.connection.execute(<<-SQL
+      UPDATE spree_products
+      SET sku = spree_variants.sku
+      FROM spree_variants
+      WHERE spree_variants.product_id = spree_products.id
+        AND spree_variants.is_master = true
+    SQL
+    )
+  end
+end

db/schema.rb

@@ -745,6 +745,7 @@ ActiveRecord::Schema[7.0].define(version: 2023_05_22_120633) do
     t.text "notes"
     t.integer "primary_taxon_id", null: false
     t.boolean "inherits_properties", default: true, null: false
+    t.string "sku", limit: 255, default: "", null: false
     t.index ["available_on"], name: "index_products_on_available_on"
     t.index ["deleted_at"], name: "index_products_on_deleted_at"
     t.index ["name"], name: "index_products_on_name"