Add index on spree_adjustments.order_id

app/controllers/spree/admin/adjustments_controller.rb

@@ -2,16 +2,18 @@ module Spree
   module Admin
     class AdjustmentsController < ::Admin::ResourceController
       belongs_to 'spree/order', find_by: :number
-      destroy.after :reload_order
 
       prepend_before_action :set_included_tax, only: [:create, :update]
+      before_action :set_order_id, only: [:create, :update]
+      after_action :update_order, only: [:create, :update, :destroy]
       before_action :set_default_tax_rate, only: :edit
       before_action :enable_updates, only: :update
 
       private
 
-      def reload_order
+      def update_order
         @order.reload
+        @order.update!
       end
 
       def collection
@@ -22,6 +24,10 @@ module Spree
         parent.all_adjustments.eligible.find(params[:id])
       end
 
+      def set_order_id
+        @adjustment.order_id = parent.id
+      end
+
       # Choose a default tax rate to show on the edit form. The adjustment stores its included
       # tax in dollars, but doesn't store the source of the tax (ie. TaxRate that generated it).
       # We guess which tax rate here, choosing:

db/migrate/20210312095840_add_index_to_adjustments.rb

@@ -0,0 +1,5 @@
+class AddIndexToAdjustments < ActiveRecord::Migration
+  def change
+    add_index :spree_adjustments, :order_id
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20210216203057) do
+ActiveRecord::Schema.define(version: 20210312095840) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -399,6 +399,7 @@ ActiveRecord::Schema.define(version: 20210216203057) do
   end
 
   add_index "spree_adjustments", ["adjustable_id"], name: "index_adjustments_on_order_id", using: :btree
+  add_index "spree_adjustments", ["order_id"], name: "index_spree_adjustments_on_order_id", using: :btree
 
   create_table "spree_assets", force: :cascade do |t|
     t.integer  "viewable_id"

spec/controllers/spree/admin/adjustments_controller_spec.rb

@@ -21,6 +21,9 @@ module Spree
           expect(a.label).to eq('Testing included tax')
           expect(a.amount).to eq(110)
           expect(a.included_tax).to eq(0)
+          expect(a.order_id).to eq(order.id)
+
+          expect(order.reload.total).to eq 110
         end
 
         it "calculates included tax when a tax rate is provided" do
@@ -31,6 +34,9 @@ module Spree
           expect(a.label).to eq('Testing included tax')
           expect(a.amount).to eq(110)
           expect(a.included_tax).to eq(10)
+          expect(a.order_id).to eq(order.id)
+
+          expect(order.reload.total).to eq 110
         end
       end
 
@@ -47,6 +53,9 @@ module Spree
           expect(a.label).to eq('Testing included tax')
           expect(a.amount).to eq(110)
           expect(a.included_tax).to eq(0)
+          expect(a.order_id).to eq(order.id)
+
+          expect(order.reload.total).to eq 110
         end
 
         it "calculates included tax when a tax rate is provided" do
@@ -57,6 +66,9 @@ module Spree
           expect(a.label).to eq('Testing included tax')
           expect(a.amount).to eq(110)
           expect(a.included_tax).to eq(10)
+          expect(a.order_id).to eq(order.id)
+
+          expect(order.reload.total).to eq 110
         end
       end
     end