Generate invoice earlier in payment method change process (Z#23179304) (#4763)

* Generate invoice earlier in payment method change process (Z##23179304)

* Resolve review note

src/pretix/base/services/orders.py

@@ -3114,14 +3114,34 @@ def change_payment_provider(order: Order, payment_provider, amount=None, new_pay
             }
         )
 
+    new_invoice_created = False
     if recreate_invoices:
+        # Lock to prevent duplicate invoice creation
+        order = Order.objects.select_for_update(of=OF_SELF).get(pk=order.pk)
+
         i = order.invoices.filter(is_cancellation=False).last()
-        if i and order.total != oldtotal and not i.canceled:
+        has_active_invoice = i and not i.canceled
+
+        if has_active_invoice and order.total != oldtotal:
             generate_cancellation(i)
             generate_invoice(order)
+            new_invoice_created = True
+
+        elif (not has_active_invoice or order.invoice_dirty) and invoice_qualified(order):
+            if order.event.settings.get('invoice_generate') == 'True' or (
+                order.event.settings.get('invoice_generate') == 'paid' and
+                new_payment.payment_provider.requires_invoice_immediately
+            ):
+                if has_active_invoice:
+                    generate_cancellation(i)
+                i = generate_invoice(order)
+                new_invoice_created = True
+                order.log_action('pretix.event.order.invoice.generated', data={
+                    'invoice': i.pk
+                })
 
     order.create_transactions()
-    return old_fee, new_fee, fee, new_payment
+    return old_fee, new_fee, fee, new_payment, new_invoice_created
 
 
 @receiver(order_paid, dispatch_uid="pretixbase_order_paid_giftcards")

src/pretix/plugins/banktransfer/tasks.py

@@ -267,8 +267,9 @@ def _handle_transaction(trans: BankTransaction, matches: tuple, event: Event = N
 
         if created:
             # We're perform a payment method switching on-demand here
-            old_fee, new_fee, fee, p = change_payment_provider(order, p.payment_provider, p.amount,
+            old_fee, new_fee, fee, p, new_invoice_created = change_payment_provider(
-                                                               new_payment=p, create_log=False)  # noqa
+                order, p.payment_provider, p.amount, new_payment=p, create_log=False
+            )  # noqa
             if fee:
                 p.fee = fee
                 p.save(update_fields=['fee'])

src/pretix/presale/views/order.py

@@ -86,7 +86,6 @@ from pretix.base.signals import order_modified, register_ticket_outputs
 from pretix.base.templatetags.money import money_filter
 from pretix.base.views.mixins import OrderQuestionsViewMixin
 from pretix.base.views.tasks import AsyncAction
-from pretix.helpers import OF_SELF
 from pretix.helpers.http import redirect_to_url
 from pretix.helpers.safedownload import check_token
 from pretix.multidomain.urlreverse import build_absolute_uri, eventreverse
@@ -445,22 +444,8 @@ class OrderPaymentConfirm(EventViewMixin, OrderDetailMixin, TemplateView):
 
     def post(self, request, *args, **kwargs):
         try:
-            with transaction.atomic():
+            self.payment.process_initiated = True
-                order = Order.objects.select_for_update(of=OF_SELF).get(pk=self.order.pk)
+            self.payment.save(update_fields=['process_initiated'])
-                i = order.invoices.filter(is_cancellation=False).last()
-                has_active_invoice = i and not i.canceled
-                if (not has_active_invoice or order.invoice_dirty) and invoice_qualified(order):
-                    if self.request.event.settings.get('invoice_generate') == 'True' or (
-                            self.request.event.settings.get('invoice_generate') == 'paid' and self.payment.payment_provider.requires_invoice_immediately):
-                        if has_active_invoice:
-                            generate_cancellation(i)
-                        i = generate_invoice(order)
-                        order.log_action('pretix.event.order.invoice.generated', data={
-                            'invoice': i.pk
-                        })
-                        messages.success(self.request, _('An invoice has been generated.'))
-                self.payment.process_initiated = True
-                self.payment.save(update_fields=['process_initiated'])
             resp = self.payment.payment_provider.execute_payment(request, self.payment)
         except PaymentException as e:
             messages.error(request, str(e))
@@ -674,7 +659,12 @@ class OrderPayChangeMethod(EventViewMixin, OrderDetailMixin, TemplateView):
                 request.session['payment_change_{}'.format(self.order.pk)] = '1'
 
                 with transaction.atomic():
-                    old_fee, new_fee, fee, newpayment = change_payment_provider(self.order, p['provider'], None)
+                    old_fee, new_fee, fee, newpayment, new_invoice_created = change_payment_provider(
+                        self.order, p['provider'], None
+                    )
+
+                if new_invoice_created:
+                    messages.success(self.request, _('An invoice has been generated.'))
 
                 resp = p['provider'].payment_prepare(request, newpayment)
                 if isinstance(resp, str):