Move more code into change_payment_provider

src/pretix/base/services/orders.py

@@ -1684,7 +1684,9 @@ def cancel_order(self, order: int, user: int=None, send_mail: bool=True, api_tok
         raise OrderError(error_messages['busy'])
 
 
-def change_payment_provider(order: Order, payment_provider, amount=None, new_payment=None):
+def change_payment_provider(order: Order, payment_provider, amount=None, new_payment=None, create_log=True,
+                            recreate_invoices=True):
+    oldtotal = order.total
     e = OrderPayment.objects.filter(fee=OuterRef('pk'), state__in=(OrderPayment.PAYMENT_STATE_CONFIRMED,
                                                                    OrderPayment.PAYMENT_STATE_REFUNDED))
     open_fees = list(
@@ -1730,4 +1732,30 @@ def change_payment_provider(order: Order, payment_provider, amount=None, new_pay
 
     order.total = (order.positions.aggregate(sum=Sum('price'))['sum'] or 0) + (order.fees.aggregate(sum=Sum('value'))['sum'] or 0)
     order.save(update_fields=['total'])
-    return old_fee, new_fee, fee
+
+    if not new_payment:
+        new_payment = order.payments.create(
+            state=OrderPayment.PAYMENT_STATE_CREATED,
+            provider=payment_provider.identifier,
+            amount=order.pending_sum,
+            fee=fee
+        )
+    if create_log and new_payment:
+        order.log_action(
+            'pretix.event.order.payment.changed' if open_payment else 'pretix.event.order.payment.started',
+            {
+                'fee': new_fee,
+                'old_fee': old_fee,
+                'provider': payment_provider.identifier,
+                'payment': new_payment.pk,
+                'local_id': new_payment.local_id,
+            }
+        )
+
+    if recreate_invoices:
+        i = order.invoices.filter(is_cancellation=False).last()
+        if i and order.total != oldtotal:
+            generate_cancellation(i)
+            generate_invoice(order)
+
+    return old_fee, new_fee, fee, new_payment

src/pretix/plugins/banktransfer/tasks.py

@@ -119,8 +119,9 @@ def _handle_transaction(trans: BankTransaction, code: str, event: Event=None, or
         }
 
         if created:
-            # We're perform a payment method switchign on-demand here
+            # We're perform a payment method switching on-demand here
-            old_fee, new_fee, fee = change_payment_provider(trans.order, p.payment_provider, p.amount, new_payment=p)  # noqa
+            old_fee, new_fee, fee, p = change_payment_provider(trans.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

@@ -25,8 +25,7 @@ from pretix.base.models.orders import (
 )
 from pretix.base.payment import PaymentException
 from pretix.base.services.invoices import (
-    generate_cancellation, generate_invoice, invoice_pdf, invoice_pdf_task,
+    generate_invoice, invoice_pdf, invoice_pdf_task, invoice_qualified,
-    invoice_qualified,
 )
 from pretix.base.services.mail import SendMailException
 from pretix.base.services.orders import cancel_order, change_payment_provider
@@ -543,34 +542,13 @@ class OrderPayChangeMethod(EventViewMixin, OrderDetailMixin, TemplateView):
 
     def post(self, request, *args, **kwargs):
         self.request = request
-        oldtotal = self.order.total
         for p in self.provider_forms:
             if p['provider'].identifier == request.POST.get('payment', ''):
                 request.session['payment'] = p['provider'].identifier
                 request.session['payment_change_{}'.format(self.order.pk)] = '1'
 
                 with transaction.atomic():
-                    old_fee, new_fee, fee = change_payment_provider(self.order, p['provider'], None)
+                    old_fee, new_fee, fee, newpayment = change_payment_provider(self.order, p['provider'], None)
-                    newpayment = self.order.payments.create(
-                        state=OrderPayment.PAYMENT_STATE_CREATED,
-                        provider=p['provider'].identifier,
-                        amount=self.order.pending_sum,
-                        fee=fee
-                    )
-                    self.order.log_action(
-                        'pretix.event.order.payment.changed' if self.open_payment else 'pretix.event.order.payment.started',
-                        {
-                            'fee': new_fee,
-                            'old_fee': old_fee,
-                            'provider': newpayment.provider,
-                            'payment': newpayment.pk,
-                            'local_id': newpayment.local_id,
-                        }
-                    )
-                    i = self.order.invoices.filter(is_cancellation=False).last()
-                    if i and self.order.total != oldtotal:
-                        generate_cancellation(i)
-                        generate_invoice(self.order)
 
                 resp = p['provider'].payment_prepare(request, newpayment)
                 if isinstance(resp, str):