Clarify updating only pre-existing customers

app/models/spree/order.rb

@@ -708,10 +708,8 @@ module Spree
     end
 
     def ensure_customer
-      self.customer ||= CustomerSyncer.find_customer(self)
+      self.customer ||= CustomerSyncer.find_and_update_customer(self)
       self.customer ||= CustomerSyncer.create_customer(self) if require_customer?
-
-      CustomerSyncer.new(self).synchronise_customer_email
     end
 
     def update_adjustment!(adjustment)

app/services/customer_syncer.rb

@@ -4,11 +4,32 @@
 #
 # P.S.: I almost couldn't resist to call this CustomerService.
 class CustomerSyncer
+  def self.find_and_update_customer(order)
+    find_customer(order).tap { |customer| synchronise_email(order, customer) }
+  end
+
   def self.find_customer(order)
     order.user&.customers&.of(order.distributor)&.first ||
       Customer.of(order.distributor).find_by(email: customer_email(order))
   end
 
+  def self.synchronise_email(order, customer)
+    email = order.user&.email
+
+    return unless email && customer && email != customer.email
+
+    duplicate = Customer.find_by(email: email, enterprise: order.distributor)
+
+    if duplicate.present?
+      Spree::Order.where(customer_id: duplicate.id).update_all(customer_id: customer.id)
+      Subscription.where(customer_id: duplicate.id).update_all(customer_id: customer.id)
+
+      duplicate.destroy
+    end
+
+    customer.update(email: email)
+  end
+
   def self.create_customer(order)
     Customer.create(
       enterprise: order.distributor,
@@ -24,28 +45,4 @@ class CustomerSyncer
   def self.customer_email(order)
     (order.user&.email || order.email)&.downcase
   end
-
-  attr_reader :customer, :distributor, :user
-
-  def initialize(order)
-    @customer = order.customer
-    @distributor = order.distributor
-    @user = order.user
-  end
-
-  # Update the customer record if the user changed their email address.
-  def synchronise_customer_email
-    return unless user && customer && user.email != customer.email
-
-    duplicate = Customer.find_by(email: user.email, enterprise: distributor)
-
-    if duplicate.present?
-      Spree::Order.where(customer_id: duplicate.id).update_all(customer_id: customer.id)
-      Subscription.where(customer_id: duplicate.id).update_all(customer_id: customer.id)
-
-      duplicate.destroy
-    end
-
-    customer.update(email: user.email)
-  end
 end