Script to add master variants for spree_products that are missing them

add_missing_master_variants.rb

puts "Rails environment is #{Rails.env}"

products_without_master = Spree::Product.joins('left outer join spree_variants sv on sv.product_id = spree_products.id and sv.is_master = 1').where('sv.id is null').all
ids_without_master = products_without_master.map(&:id)

puts "Spree products without master variants are #{ids_without_master.count} in number and have ids #{ids_without_master}"
updated_at_values = products_without_master.map(&:updated_at)

ActiveRecord::Base.transaction do
  puts "Creating missing master variants inside a transaction..."
  products_without_master.each do |sp|
    updated_at = sp.updated_at
    Spree::Variant.create!(product_id: id, is_master: true, cost_price: sp.teni_product.transfer_price)
    sp.update_column(:updated_at, updated_at)
  end 
  new_updated_at_values = Spree::Product.where(id: ids_without_master).pluck(:updated_at)
  if updated_at_values == new_updated_at_values 
     puts "Congrats, updated_at values were preserved"
  else
     puts "Ugh, updated_at values were not preserved. See the differences yourself. Updated_at originally was #{updated_at_values}"
     puts "Now, it is #{new_updated_at_values}"
     puts "Cancelling transcation because of this. Bad luck."
  end 

  puts "Now ids without master = #{ids_without_master}"

#  raise "Need to cancel transaction -- just testing"
end