Merge tax updating code and deprecate Order#create_tax_charge!

Previously we had two different sets of tax updating code.  One was
Order#create_tax_charge! and the other was the code in OrderUpdater.
The effect of the former encompasses the effect of the latter, so
functionally we can merge these.

This may result in increased load since we're now using the more
encompassing method which was more heavyweight.

CHANGELOG.md

@@ -18,7 +18,7 @@
 * Remove callback `Spree::LineItem.after_create :update_tax_charge`
 
  Any code that creates `LineItem`s outside the context of OrderContents
- should ensure that it calls `order.create_tax_charge!` after doing so.
+ should ensure that it calls `order.update!` after doing so.
 
 * Mark `Spree::Tax::ItemAdjuster` as api-private
 

core/app/models/spree/order.rb

@@ -17,7 +17,7 @@ module Spree
  # `checkout_allowed?` or `payment_required?`.
  #
  # * Implements an interface for mutating the order with methods like
- # `create_tax_charge!` and `fulfill!`.
+ # `empty!` and `fulfill!`.
  #
  class Order < Spree::Base
  ORDER_NUMBER_LENGTH = 9
@@ -348,9 +348,11 @@ def line_item_options_match(line_item, options)
 
  # Creates new tax charges if there are any applicable rates. If prices already
  # include taxes then price adjustments are created instead.
+ # @deprecated This now happens during #update!
  def create_tax_charge!
  Spree::Tax::OrderAdjuster.new(self).adjust!
  end
+ deprecate create_tax_charge!: :update!, deprecator: Spree::Deprecation
 
  def outstanding_balance
  # If reimbursement has happened add it back to total to prevent balance_due payment state

core/app/models/spree/order/checkout.rb

@@ -78,7 +78,6 @@ def self.define_state_machine!
 
  after_transition to: :complete, do: :add_payment_sources_to_wallet
  before_transition to: :payment, do: :set_shipments_cost
- before_transition to: :payment, do: :create_tax_charge!
  before_transition to: :payment, do: :assign_default_credit_card
 
  before_transition to: :confirm, do: :add_store_credit_payments
@@ -90,7 +89,6 @@ def self.define_state_machine!
  before_transition from: :cart, do: :ensure_line_items_present
 
  if states[:address]
- before_transition from: :address, do: :create_tax_charge!
  before_transition to: :address, do: :assign_default_addresses!
  before_transition from: :address, do: :persist_user_address!
  end

core/app/models/spree/order_contents.rb

@@ -36,8 +36,6 @@ def remove_line_item(line_item, options = {})
 
  def update_cart(params)
  if order.update_attributes(params)
- order.create_tax_charge!
-
  unless order.completed?
  order.line_items = order.line_items.select { |li| li.quantity > 0 }
  # Update totals, then check if the order is eligible for any cart promotions.
@@ -77,7 +75,6 @@ def after_add_or_remove(line_item, options = {})
  shipment = options[:shipment]
  shipment.present? ? shipment.update_amounts : order.ensure_updated_shipments
  PromotionHandler::Cart.new(order, line_item).activate
- order.create_tax_charge!
  reload_totals
  line_item
  end

core/app/models/spree/order_updater.rb

@@ -197,10 +197,10 @@ def update_order_promotions
  end
 
  def update_taxes
+ Spree::Tax::OrderAdjuster.new(order).adjust!
+
  [*line_items, *shipments].each do |item|
  tax_adjustments = item.adjustments.select(&:tax?)
-
- tax_adjustments.each(&:update!)
  # Tax adjustments come in not one but *two* exciting flavours:
  # Included & additional
 

core/lib/spree/core/unreturned_item_charger.rb

@@ -24,7 +24,6 @@ def charge_for_items
  new_order.associate_user!(@original_order.user) if @original_order.user
 
  add_exchange_variants_to_order
- new_order.create_tax_charge!
  set_shipment_for_new_order
 
  new_order.update!

core/lib/spree/testing_support/factories/order_factory.rb

@@ -45,7 +45,6 @@
  create(:line_item, attributes)
  end
  order.line_items.reload
- order.create_tax_charge!
 
  create(:shipment, order: order, cost: evaluator.shipment_cost, shipping_method: evaluator.shipping_method, stock_location: evaluator.stock_location)
  order.shipments.reload

core/spec/lib/spree/core/unreturned_item_charger_spec.rb

@@ -53,7 +53,6 @@
 
  it "applies tax" do
  exchange_order = exchange_shipment.order
- exchange_order.create_tax_charge!
  exchange_order.update!
  subject
  expect(new_order.additional_tax_total).to be > 0

core/spec/models/spree/order_contents_spec.rb

@@ -256,11 +256,6 @@
  }.to change { subject.order.total }
  end
 
- it "updates tax adjustments" do
- expect(subject.order).to receive(:create_tax_charge!)
- subject.update_cart params
- end
-
  context "submits item quantity 0" do
  let(:params) do
  { line_items_attributes: {