Do not use deepcopy on models

src/pretix/base/services/invoices.py

@@ -1,4 +1,3 @@
-import copy
 import json
 import logging
 import urllib.error
@@ -27,6 +26,7 @@ from pretix.base.settings import GlobalSettingsObject
 from pretix.base.signals import periodic_task
 from pretix.celery_app import app
 from pretix.helpers.database import rolledback_transaction
+from pretix.helpers.models import modelcopy
 
 logger = logging.getLogger(__name__)
 
@@ -171,7 +171,7 @@ def build_cancellation(invoice: Invoice):
 
 
 def generate_cancellation(invoice: Invoice, trigger_pdf=True):
-    cancellation = copy.deepcopy(invoice)
+    cancellation = modelcopy(invoice)
     cancellation.pk = None
     cancellation.invoice_no = None
     cancellation.prefix = None

src/pretix/base/services/orders.py

@@ -1,4 +1,3 @@
-import copy
 import json
 import logging
 from collections import Counter, namedtuple
@@ -44,6 +43,7 @@ from pretix.base.signals import (
     allow_ticket_download, order_fee_calculation, order_placed, periodic_task,
 )
 from pretix.celery_app import app
+from pretix.helpers.models import modelcopy
 from pretix.multidomain.urlreverse import build_absolute_uri
 
 error_messages = {
@@ -923,7 +923,7 @@ class OrderChangeManager:
             op.save()
 
         try:
-            ia = copy.deepcopy(self.order.invoice_address)
+            ia = modelcopy(self.order.invoice_address)
             ia.pk = None
             ia.order = split_order
             ia.save()
@@ -947,7 +947,7 @@ class OrderChangeManager:
             split_order.total += fee.value
 
         for fee in self.order.fees.exclude(fee_type=OrderFee.FEE_TYPE_PAYMENT):
-            new_fee = copy.deepcopy(fee)
+            new_fee = modelcopy(fee)
             new_fee.pk = None
             new_fee.order = split_order
             split_order.total += new_fee.value

src/pretix/control/forms/item.py

@@ -1,5 +1,3 @@
-import copy
-
 from django import forms
 from django.core.exceptions import ValidationError
 from django.db.models import Max
@@ -18,6 +16,7 @@ from pretix.base.models.items import ItemAddOn
 from pretix.base.signals import item_copy_data
 from pretix.control.forms import SplitDateTimePickerWidget
 from pretix.control.forms.widgets import Select2
+from pretix.helpers.models import modelcopy
 from pretix.helpers.money import change_decimal_field
 
 
@@ -78,7 +77,7 @@ class QuotaForm(I18nModelForm):
         self.instance = kwargs.get('instance', None)
         self.event = kwargs.get('event')
         items = kwargs.pop('items', None) or self.event.items.prefetch_related('variations')
-        self.original_instance = copy.deepcopy(self.instance) if self.instance else None
+        self.original_instance = modelcopy(self.instance) if self.instance else None
         initial = kwargs.get('initial', {})
         if self.instance and self.instance.pk:
             initial['itemvars'] = [str(i.pk) for i in self.instance.items.all()] + [

src/pretix/control/forms/vouchers.py

@@ -1,5 +1,3 @@
-import copy
-
 from django import forms
 from django.core.exceptions import ObjectDoesNotExist, ValidationError
 from django.db.models.functions import Lower
@@ -11,6 +9,7 @@ from pretix.base.models import Item, Voucher
 from pretix.control.forms import SplitDateTimePickerWidget
 from pretix.control.forms.widgets import Select2, Select2ItemVarQuota
 from pretix.control.signals import voucher_form_validation
+from pretix.helpers.models import modelcopy
 
 
 class FakeChoiceField(forms.ChoiceField):
@@ -45,7 +44,7 @@ class VoucherForm(I18nModelForm):
         instance = kwargs.get('instance')
         initial = kwargs.get('initial')
         if instance:
-            self.initial_instance_data = copy.deepcopy(instance)
+            self.initial_instance_data = modelcopy(instance)
             try:
                 if instance.variation:
                     initial['itemvar'] = '%d-%d' % (instance.item.pk, instance.variation.pk)
@@ -217,7 +216,7 @@ class VoucherBulkForm(VoucherForm):
     def save(self, event, *args, **kwargs):
         objs = []
         for code in self.cleaned_data['codes']:
-            obj = copy.deepcopy(self.instance)
+            obj = modelcopy(self.instance)
             obj.event = event
             obj.code = code
             data = dict(self.cleaned_data)

src/pretix/control/views/subevents.py

@@ -33,6 +33,7 @@ from pretix.control.forms.subevents import (
 from pretix.control.permissions import EventPermissionRequiredMixin
 from pretix.control.views import PaginationMixin
 from pretix.control.views.event import MetaDataEditorMixin
+from pretix.helpers.models import modelcopy
 
 
 class SubEventList(EventPermissionRequiredMixin, PaginationMixin, ListView):
@@ -424,7 +425,7 @@ class SubEventCreate(SubEventEditorMixin, EventPermissionRequiredMixin, CreateVi
         kwargs = super().get_form_kwargs()
         kwargs['event'] = self.request.event
         if self.copy_from:
-            i = copy.deepcopy(self.copy_from)
+            i = modelcopy(self.copy_from)
             i.pk = None
             kwargs['instance'] = i
         else:

src/pretix/helpers/models.py

@@ -1,3 +1,5 @@
+import copy
+
 from django.db import models
 
 
@@ -8,3 +10,14 @@ class Thumbnail(models.Model):
 
     class Meta:
         unique_together = (('source', 'size'),)
+
+
+def modelcopy(obj: models.Model):
+    n = copy.copy(obj)
+    for f in obj._meta.fields:
+        val = getattr(obj, f.name)
+        if isinstance(val, models.Model):
+            setattr(n, f.name, val)
+        else:
+            setattr(n, f.name, copy.deepcopy(val))
+    return n

src/tests/control/test_vouchers.py

@@ -394,6 +394,12 @@ class VoucherFormTest(SoupTest):
             'itemvar': '%d' % self.shirt.pk,
         })
 
+    def test_create_bulk_many(self):
+        self._create_bulk_vouchers({
+            'codes': 'ABCDE\nDEFGH\nIJKLM\nNOPQR\nSTUVW\nXYZ',
+            'itemvar': '%d' % self.ticket.pk,
+        })
+
     def test_create_blocking_bulk_quota_full(self):
         self.quota_tickets.size = 0
         self.quota_tickets.save()