Preliminary migration

This reverts commit b847612e1a.

src/pretix/base/logentrytype_registry.py

@@ -0,0 +1,165 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+from collections import defaultdict
+from typing import Optional
+
+from django.urls import reverse
+from django.utils.html import format_html
+from django.utils.translation import gettext_lazy as _
+
+from pretix.base.signals import EventPluginRegistry
+
+
+def make_link(a_map, wrapper, is_active=True, event=None, plugin_name=None):
+    if a_map:
+        if 'href' not in a_map:
+            a_map['val'] = format_html('<i>{val}</i>', **a_map)
+        elif is_active:
+            a_map['val'] = format_html('<a href="{href}">{val}</a>', **a_map)
+        elif event and plugin_name:
+            a_map['val'] = format_html(
+                '<i>{val}</i> <a href="{plugin_href}">'
+                '<span data-toggle="tooltip" title="{errmes}" class="fa fa-warning fa-fw"></span></a>',
+                **a_map,
+                errmes=_("The relevant plugin is currently not active. To activate it, click here to go to the plugin settings."),
+                plugin_href=reverse('control:event.settings.plugins', kwargs={
+                    'organizer': event.organizer.slug,
+                    'event': event.slug,
+                }) + '#plugin_' + plugin_name,
+            )
+        else:
+            a_map['val'] = format_html(
+                '<i>{val}</i> <span data-toggle="tooltip" title="{errmes}" class="fa fa-warning fa-fw"></span>',
+                **a_map,
+                errmes=_("The relevant plugin is currently not active."),
+            )
+        return format_html(wrapper, **a_map)
+
+
+class LogEntryTypeRegistry(EventPluginRegistry):
+    def __init__(self):
+        super().__init__({'action_type': lambda o: getattr(o, 'action_type')})
+
+    def register(self, *objs):
+        for obj in objs:
+            if not isinstance(obj, LogEntryType):
+                raise TypeError('Entries must be derived from LogEntryType')
+
+            if obj.__module__.startswith('pretix.base.'):
+                raise TypeError('Must not register base classes, only derived ones')
+
+        return super().register(*objs)
+
+    def new_from_dict(self, data):
+        """
+        Register multiple instance of a `LogEntryType` class with different `action_type`
+        and plain text strings, as given by the items of the specified data dictionary.
+
+        This method is designed to be used as a decorator as follows:
+
+        .. code-block:: python
+
+            @log_entry_types.new_from_dict({
+                'pretix.event.item.added': _('The product has been created.'),
+                'pretix.event.item.changed': _('The product has been changed.'),
+                # ...
+            })
+            class CoreItemLogEntryType(ItemLogEntryType):
+                # ...
+
+        :param data: action types and descriptions
+                     ``{"some_action_type": "Plain text description", ...}``
+        """
+        def reg(clz):
+            for action_type, plain in data.items():
+                self.register(clz(action_type=action_type, plain=plain))
+            return clz
+        return reg
+
+
+"""
+Registry for LogEntry types.
+
+Each entry in this registry should be an instance of a subclass of ``LogEntryType``.
+They are annotated with their ``action_type`` and the defining ``plugin``.
+"""
+log_entry_types = LogEntryTypeRegistry()
+
+
+class LogEntryType:
+    """
+    Base class for a type of LogEntry, identified by its action_type.
+    """
+
+    def __init__(self, action_type=None, plain=None):
+        if action_type:
+            self.action_type = action_type
+        if plain:
+            self.plain = plain
+
+    def display(self, logentry, data):
+        """
+        Returns the message to be displayed for a given logentry of this type.
+
+        :return: `str` or `LazyI18nString`
+        """
+        if hasattr(self, 'plain'):
+            plain = str(self.plain)
+            if '{' in plain:
+                data = defaultdict(lambda: '?', data)
+                return plain.format_map(data)
+            else:
+                return plain
+
+    def get_object_link_info(self, logentry) -> Optional[dict]:
+        """
+        Return information to generate a link to the `content_object` of a given log entry.
+
+        Not implemented in the base class, causing the object link to be omitted.
+
+        :return: Dictionary with the keys ``href`` (URL to view/edit the object) and
+                 ``val`` (text for the anchor element)
+        """
+        pass
+
+    def get_object_link(self, logentry):
+        a_map = self.get_object_link_info(logentry)
+        return make_link(a_map, self.object_link_wrapper)
+
+    object_link_wrapper = '{val}'
+
+    def shred_pii(self, logentry):
+        """
+        To be used for shredding personally identified information contained in the data field of a LogEntry of this
+        type.
+        """
+        raise NotImplementedError
+
+
+class NoOpShredderMixin:
+    def shred_pii(self, logentry):
+        pass
+
+
+class ClearDataShredderMixin:
+    def shred_pii(self, logentry):
+        logentry.data = None

src/pretix/base/logentrytypes.py

@@ -19,137 +19,20 @@
 # You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
 # <https://www.gnu.org/licenses/>.
 #
-from collections import defaultdict
+from typing import Optional
 
 from django.urls import reverse
-from django.utils.html import escape
 from django.utils.translation import gettext_lazy as _, pgettext_lazy
 
-from pretix.base.signals import EventPluginRegistry
+from pretix.base.models import (
+    Discount, Item, ItemCategory, Order, Question, Quota, SubEvent, TaxRule,
+    Voucher,
+)
 
-
-def make_link(a_map, wrapper, is_active=True, event=None, plugin_name=None):
-    if a_map:
-        if is_active:
-            a_map['val'] = '<a href="{href}">{val}</a>'.format_map(a_map)
-        elif event and plugin_name:
-            a_map['val'] = (
-                '<i>{val}</i> <a href="{plugin_href}">'
-                '<span data-toggle="tooltip" title="{errmes}" class="fa fa-warning fa-fw"></span></a>'
-            ).format_map({
-                **a_map,
-                "errmes": _("The relevant plugin is currently not active. To activate it, click here to go to the plugin settings."),
-                "plugin_href": reverse('control:event.settings.plugins', kwargs={
-                    'organizer': event.organizer.slug,
-                    'event': event.slug,
-                }) + '#plugin_' + plugin_name,
-            })
-        else:
-            a_map['val'] = '<i>{val}</i> <span data-toggle="tooltip" title="{errmes}" class="fa fa-warning fa-fw"></span>'.format_map({
-                **a_map,
-                "errmes": _("The relevant plugin is currently not active."),
-            })
-        return wrapper.format_map(a_map)
-
-
-class LogEntryTypeRegistry(EventPluginRegistry):
-    def __init__(self):
-        super().__init__({'action_type': lambda o: getattr(o, 'action_type')})
-
-    def register(self, *objs):
-        for obj in objs:
-            if not isinstance(obj, LogEntryType):
-                raise TypeError('Entries must be derived from LogEntryType')
-
-            if obj.__module__ == LogEntryType.__module__:
-                raise TypeError('Must not register base classes, only derived ones')
-
-        return super().register(*objs)
-
-    def new_from_dict(self, data):
-        """
-        Register multiple instance of a `LogEntryType` class with different `action_type`
-        and plain text strings, as given by the items of the specified data dictionary.
-
-        This method is designed to be used as a decorator as follows:
-
-        .. code-block:: python
-
-            @log_entry_types.new_from_dict({
-                'pretix.event.item.added': _('The product has been created.'),
-                'pretix.event.item.changed': _('The product has been changed.'),
-                # ...
-            })
-            class CoreItemLogEntryType(ItemLogEntryType):
-                # ...
-
-        :param data: action types and descriptions
-                     ``{"some_action_type": "Plain text description", ...}``
-        """
-        def reg(clz):
-            for action_type, plain in data.items():
-                self.register(clz(action_type=action_type, plain=plain))
-            return clz
-        return reg
-
-
-"""
-Registry for LogEntry types.
-
-Each entry in this registry should be an instance of a subclass of ``LogEntryType``.
-They are annotated with their ``action_type`` and the defining ``plugin``.
-"""
-log_entry_types = LogEntryTypeRegistry()
-
-
-class LogEntryType:
-    """
-    Base class for a type of LogEntry, identified by its action_type.
-    """
-
-    def __init__(self, action_type=None, plain=None):
-        if action_type:
-            self.action_type = action_type
-        if plain:
-            self.plain = plain
-
-    def display(self, logentry):
-        """
-        Returns the message to be displayed for a given logentry of this type.
-
-        :return: `str` or `LazyI18nString`
-        """
-        if hasattr(self, 'plain'):
-            plain = str(self.plain)
-            if '{' in plain:
-                data = defaultdict(lambda: '?', logentry.parsed_data)
-                return plain.format_map(data)
-            else:
-                return plain
-
-    def get_object_link_info(self, logentry) -> dict:
-        """
-        Return information to generate a link to the `content_object` of a given log entry.
-
-        Not implemented in the base class, causing the object link to be omitted.
-
-        :return: Dictionary with the keys ``href`` (containing a URL to view/edit the object) and ``val`` (containing the
-                 escaped text for the anchor element)
-        """
-        pass
-
-    def get_object_link(self, logentry):
-        a_map = self.get_object_link_info(logentry)
-        return make_link(a_map, self.object_link_wrapper)
-
-    object_link_wrapper = '{val}'
-
-    def shred_pii(self, logentry):
-        """
-        To be used for shredding personally identified information contained in the data field of a LogEntry of this
-        type.
-        """
-        raise NotImplementedError
+from .logentrytype_registry import (  # noqa
+    ClearDataShredderMixin, LogEntryType, NoOpShredderMixin, log_entry_types,
+    make_link, LogEntryTypeRegistry,
+)
 
 
 class EventLogEntryType(LogEntryType):
@@ -157,15 +40,27 @@ class EventLogEntryType(LogEntryType):
     Base class for any `LogEntry` type whose `content_object` is either an `Event` itself or belongs to a specific `Event`.
     """
 
-    def get_object_link_info(self, logentry) -> dict:
-        if hasattr(self, 'object_link_viewname') and logentry.content_object:
+    def get_object_link_info(self, logentry) -> Optional[dict]:
+        if hasattr(self, 'object_link_viewname'):
+            content = logentry.content_object
+            if not content:
+                if logentry.content_type_id:
+                    return {
+                        'val': _('(deleted)'),
+                    }
+                else:
+                    return
+
+            if hasattr(self, 'content_type') and not isinstance(content, self.content_type):
+                return
+
             return {
                 'href': reverse(self.object_link_viewname, kwargs={
                     'event': logentry.event.slug,
                     'organizer': logentry.event.organizer.slug,
-                    **self.object_link_args(logentry.content_object),
+                    **self.object_link_args(content),
                 }),
-                'val': escape(self.object_link_display_name(logentry.content_object)),
+                'val': self.object_link_display_name(logentry.content_object),
             }
 
     def object_link_args(self, content_object):
@@ -182,6 +77,7 @@ class EventLogEntryType(LogEntryType):
 class OrderLogEntryType(EventLogEntryType):
     object_link_wrapper = _('Order {val}')
     object_link_viewname = 'control:event.order'
+    content_type = Order
 
     def object_link_args(self, order):
         return {'code': order.code}
@@ -194,6 +90,7 @@ class VoucherLogEntryType(EventLogEntryType):
     object_link_wrapper = _('Voucher {val}…')
     object_link_viewname = 'control:event.voucher'
     object_link_argname = 'voucher'
+    content_type = Voucher
 
     def object_link_display_name(self, voucher):
         if len(voucher.code) > 6:
@@ -205,49 +102,46 @@ class ItemLogEntryType(EventLogEntryType):
     object_link_wrapper = _('Product {val}')
     object_link_viewname = 'control:event.item'
     object_link_argname = 'item'
+    content_type = Item
 
 
 class SubEventLogEntryType(EventLogEntryType):
     object_link_wrapper = pgettext_lazy('subevent', 'Date {val}')
     object_link_viewname = 'control:event.subevent'
     object_link_argname = 'subevent'
+    content_type = SubEvent
 
 
 class QuotaLogEntryType(EventLogEntryType):
     object_link_wrapper = _('Quota {val}')
     object_link_viewname = 'control:event.items.quotas.show'
     object_link_argname = 'quota'
+    content_type = Quota
 
 
 class DiscountLogEntryType(EventLogEntryType):
     object_link_wrapper = _('Discount {val}')
     object_link_viewname = 'control:event.items.discounts.edit'
     object_link_argname = 'discount'
+    content_type = Discount
 
 
 class ItemCategoryLogEntryType(EventLogEntryType):
     object_link_wrapper = _('Category {val}')
     object_link_viewname = 'control:event.items.categories.edit'
     object_link_argname = 'category'
+    content_type = ItemCategory
 
 
 class QuestionLogEntryType(EventLogEntryType):
     object_link_wrapper = _('Question {val}')
     object_link_viewname = 'control:event.items.questions.show'
     object_link_argname = 'question'
+    content_type = Question
 
 
 class TaxRuleLogEntryType(EventLogEntryType):
     object_link_wrapper = _('Tax rule {val}')
     object_link_viewname = 'control:event.settings.tax.edit'
     object_link_argname = 'rule'
-
-
-class NoOpShredderMixin:
-    def shred_pii(self, logentry):
-        pass
-
-
-class ClearDataShredderMixin:
-    def shred_pii(self, logentry):
-        logentry.data = None
+    content_type = TaxRule

src/pretix/base/migrations/0276_item_hidden_if_item_available_mode.py

@@ -0,0 +1,18 @@
+# Generated by Django 4.2.16 on 2025-01-23 11:27
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("pretixbase", "0275_alter_question_valid_number_max_and_more"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="item",
+            name="hidden_if_item_available_mode",
+            field=models.CharField(default="hide", max_length=16, null=True),
+        ),
+    ]

src/pretix/base/models/log.py

@@ -40,7 +40,7 @@ from django.contrib.contenttypes.models import ContentType
 from django.db import models
 from django.utils.functional import cached_property
 
-from pretix.base.logentrytypes import log_entry_types, make_link
+from pretix.base.logentrytype_registry import log_entry_types, make_link
 from pretix.base.signals import is_app_active, logentry_object_link
 
 
@@ -93,7 +93,7 @@ class LogEntry(models.Model):
     def display(self):
         log_entry_type, meta = log_entry_types.get(action_type=self.action_type)
         if log_entry_type:
-            return log_entry_type.display(self)
+            return log_entry_type.display(self, self.parsed_data)
 
         from ..signals import logentry_display
 

src/pretix/base/models/orders.py

@@ -355,7 +355,7 @@ class Order(LockModel, LoggedModel):
 
         if not self.testmode:
             raise TypeError("Only test mode orders can be deleted.")
-        self.event.log_action(
+        self.log_action(
             'pretix.event.order.deleted', user=user, auth=auth,
             data={
                 'code': self.code,

src/pretix/control/forms/event.py

@@ -231,7 +231,7 @@ class EventWizardBasicsForm(I18nModelForm):
             raise ValidationError({
                 'timezone': _('Your default locale must be specified.')
             })
-        if not data.get("no_taxes") and not data.get("tax_rate"):
+        if not data.get("no_taxes") and data.get("tax_rate") is None:
             raise ValidationError({
                 'tax_rate': _('You have not specified a tax rate. If you do not want us to compute sales taxes, please '
                               'check "{field}" above.').format(field=self.fields["no_taxes"].label)

src/pretix/control/logdisplay.py

@@ -33,16 +33,16 @@
 # distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations under the License.
 
-import json
 from collections import defaultdict
 from decimal import Decimal
+from typing import Optional
 
 import bleach
 import dateutil.parser
 from django.dispatch import receiver
 from django.urls import reverse
 from django.utils.formats import date_format
-from django.utils.html import escape
+from django.utils.html import escape, format_html
 from django.utils.safestring import mark_safe
 from django.utils.translation import gettext_lazy as _, pgettext_lazy
 from i18nfield.strings import LazyI18nString
@@ -68,128 +68,212 @@ OVERVIEW_BANLIST = [
 ]
 
 
-def _display_order_changed(event: Event, logentry: LogEntry):
-    data = json.loads(logentry.data)
+class OrderChangeLogEntryType(OrderLogEntryType):
+    prefix = _('The order has been changed:')
 
-    text = _('The order has been changed:')
-    if logentry.action_type == 'pretix.event.order.changed.item':
+    def display(self, logentry, data):
+        return self.prefix + ' ' + self.display_prefixed(logentry.event, logentry, data)
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
+        return super().display(logentry, data)
+
+
+class OrderPositionChangeLogEntryType(OrderChangeLogEntryType):
+    prefix = _('The order has been changed:')
+
+    def display(self, logentry, data):
+        return super().display(logentry, {**data, 'posid': data.get('positionid', '?')})
+
+
+@log_entry_types.new()
+class OrderItemChanged(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.item'
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
         old_item = str(event.items.get(pk=data['old_item']))
         if data['old_variation']:
             old_item += ' - ' + str(ItemVariation.objects.get(item__event=event, pk=data['old_variation']))
         new_item = str(event.items.get(pk=data['new_item']))
         if data['new_variation']:
             new_item += ' - ' + str(ItemVariation.objects.get(item__event=event, pk=data['new_variation']))
-        return text + ' ' + _('Position #{posid}: {old_item} ({old_price}) changed '
-                              'to {new_item} ({new_price}).').format(
+        return _('Position #{posid}: {old_item} ({old_price}) changed to {new_item} ({new_price}).').format(
             posid=data.get('positionid', '?'),
             old_item=old_item, new_item=new_item,
             old_price=money_filter(Decimal(data['old_price']), event.currency),
             new_price=money_filter(Decimal(data['new_price']), event.currency),
         )
-    elif logentry.action_type == 'pretix.event.order.changed.membership':
-        return text + ' ' + _('Position #{posid}: Used membership changed.').format(
-            posid=data.get('positionid', '?'),
-        )
-    elif logentry.action_type == 'pretix.event.order.changed.seat':
-        return text + ' ' + _('Position #{posid}: Seat "{old_seat}" changed '
-                              'to "{new_seat}".').format(
-            posid=data.get('positionid', '?'),
-            old_seat=data.get('old_seat'), new_seat=data.get('new_seat'),
-        )
-    elif logentry.action_type == 'pretix.event.order.changed.subevent':
+
+
+@log_entry_types.new()
+class OrderMembershipChanged(OrderPositionChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.membership'
+    plain = _('Position #{posid}: Used membership changed.')
+
+
+@log_entry_types.new()
+class OrderSeatChanged(OrderPositionChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.seat'
+    plain = _('Position #{posid}: Seat "{old_seat}" changed to "{new_seat}".')
+
+
+@log_entry_types.new()
+class OrderSubeventChanged(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.subevent'
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
         old_se = str(event.subevents.get(pk=data['old_subevent']))
         new_se = str(event.subevents.get(pk=data['new_subevent']))
-        return text + ' ' + _('Position #{posid}: Event date "{old_event}" ({old_price}) changed '
-                              'to "{new_event}" ({new_price}).').format(
+        return _('Position #{posid}: Event date "{old_event}" ({old_price}) changed '
+                 'to "{new_event}" ({new_price}).').format(
             posid=data.get('positionid', '?'),
             old_event=old_se, new_event=new_se,
             old_price=money_filter(Decimal(data['old_price']), event.currency),
             new_price=money_filter(Decimal(data['new_price']), event.currency),
         )
-    elif logentry.action_type == 'pretix.event.order.changed.price':
-        return text + ' ' + _('Price of position #{posid} changed from {old_price} '
-                              'to {new_price}.').format(
+
+
+@log_entry_types.new()
+class OrderPriceChanged(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.price'
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
+        return _('Price of position #{posid} changed from {old_price} to {new_price}.').format(
             posid=data.get('positionid', '?'),
             old_price=money_filter(Decimal(data['old_price']), event.currency),
             new_price=money_filter(Decimal(data['new_price']), event.currency),
         )
-    elif logentry.action_type == 'pretix.event.order.changed.tax_rule':
+
+
+@log_entry_types.new()
+class OrderTaxRuleChanged(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.tax_rule'
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
         if 'positionid' in data:
-            return text + ' ' + _('Tax rule of position #{posid} changed from {old_rule} '
-                                  'to {new_rule}.').format(
+            return _('Tax rule of position #{posid} changed from {old_rule} to {new_rule}.').format(
                 posid=data.get('positionid', '?'),
                 old_rule=TaxRule.objects.get(pk=data['old_taxrule']) if data['old_taxrule'] else '–',
                 new_rule=TaxRule.objects.get(pk=data['new_taxrule']),
             )
         elif 'fee' in data:
-            return text + ' ' + _('Tax rule of fee #{fee} changed from {old_rule} '
-                                  'to {new_rule}.').format(
+            return _('Tax rule of fee #{fee} changed from {old_rule} to {new_rule}.').format(
                 fee=data.get('fee', '?'),
                 old_rule=TaxRule.objects.get(pk=data['old_taxrule']) if data['old_taxrule'] else '–',
                 new_rule=TaxRule.objects.get(pk=data['new_taxrule']),
             )
-    elif logentry.action_type == 'pretix.event.order.changed.addfee':
-        return text + ' ' + str(_('A fee has been added'))
-    elif logentry.action_type == 'pretix.event.order.changed.feevalue':
-        return text + ' ' + _('A fee was changed from {old_price} to {new_price}.').format(
+
+
+@log_entry_types.new()
+class OrderFeeAdded(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.addfee'
+    plain = _('A fee has been added')
+
+
+@log_entry_types.new()
+class OrderFeeChanged(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.feevalue'
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
+        return _('A fee was changed from {old_price} to {new_price}.').format(
             old_price=money_filter(Decimal(data['old_price']), event.currency),
             new_price=money_filter(Decimal(data['new_price']), event.currency),
         )
-    elif logentry.action_type == 'pretix.event.order.changed.cancelfee':
-        return text + ' ' + _('A fee of {old_price} was removed.').format(
+
+
+@log_entry_types.new()
+class OrderFeeRemoved(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.cancelfee'
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
+        return _('A fee of {old_price} was removed.').format(
             old_price=money_filter(Decimal(data['old_price']), event.currency),
         )
-    elif logentry.action_type == 'pretix.event.order.changed.cancel':
+
+
+@log_entry_types.new()
+class OrderCanceled(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.cancel'
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
         old_item = str(event.items.get(pk=data['old_item']))
         if data['old_variation']:
             old_item += ' - ' + str(ItemVariation.objects.get(pk=data['old_variation']))
-        return text + ' ' + _('Position #{posid} ({old_item}, {old_price}) canceled.').format(
+        return _('Position #{posid} ({old_item}, {old_price}) canceled.').format(
             posid=data.get('positionid', '?'),
             old_item=old_item,
             old_price=money_filter(Decimal(data['old_price']), event.currency),
         )
-    elif logentry.action_type == 'pretix.event.order.changed.add':
+
+
+@log_entry_types.new()
+class OrderPositionAdded(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.add'
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
         item = str(event.items.get(pk=data['item']))
         if data['variation']:
             item += ' - ' + str(ItemVariation.objects.get(item__event=event, pk=data['variation']))
         if data['addon_to']:
             addon_to = OrderPosition.objects.get(order__event=event, pk=data['addon_to'])
-            return text + ' ' + _('Position #{posid} created: {item} ({price}) as an add-on to '
-                                  'position #{addon_to}.').format(
+            return _('Position #{posid} created: {item} ({price}) as an add-on to position #{addon_to}.').format(
                 posid=data.get('positionid', '?'),
                 item=item, addon_to=addon_to.positionid,
                 price=money_filter(Decimal(data['price']), event.currency),
             )
         else:
-            return text + ' ' + _('Position #{posid} created: {item} ({price}).').format(
+            return _('Position #{posid} created: {item} ({price}).').format(
                 posid=data.get('positionid', '?'),
                 item=item,
                 price=money_filter(Decimal(data['price']), event.currency),
             )
-    elif logentry.action_type == 'pretix.event.order.changed.secret':
-        return text + ' ' + _('A new secret has been generated for position #{posid}.').format(
-            posid=data.get('positionid', '?'),
-        )
-    elif logentry.action_type == 'pretix.event.order.changed.valid_from':
-        return text + ' ' + _('The validity start date for position #{posid} has been changed to {value}.').format(
+
+
+@log_entry_types.new()
+class OrderSecretChanged(OrderPositionChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.secret'
+    plain = _('A new secret has been generated for position #{posid}.')
+
+
+@log_entry_types.new()
+class OrderValidFromChanged(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.valid_from'
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
+        return _('The validity start date for position #{posid} has been changed to {value}.').format(
             posid=data.get('positionid', '?'),
             value=date_format(dateutil.parser.parse(data.get('new_value')), 'SHORT_DATETIME_FORMAT') if data.get(
                 'new_value') else '–'
         )
-    elif logentry.action_type == 'pretix.event.order.changed.valid_until':
-        return text + ' ' + _('The validity end date for position #{posid} has been changed to {value}.').format(
+
+
+@log_entry_types.new()
+class OrderValidUntilChanged(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.valid_until'
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
+        return _('The validity end date for position #{posid} has been changed to {value}.').format(
             posid=data.get('positionid', '?'),
             value=date_format(dateutil.parser.parse(data.get('new_value')), 'SHORT_DATETIME_FORMAT') if data.get('new_value') else '–'
         )
-    elif logentry.action_type == 'pretix.event.order.changed.add_block':
-        return text + ' ' + _('A block has been added for position #{posid}.').format(
-            posid=data.get('positionid', '?'),
-        )
-    elif logentry.action_type == 'pretix.event.order.changed.remove_block':
-        return text + ' ' + _('A block has been removed for position #{posid}.').format(
-            posid=data.get('positionid', '?'),
-        )
-    elif logentry.action_type == 'pretix.event.order.changed.split':
+
+
+@log_entry_types.new()
+class OrderChangedBlockAdded(OrderPositionChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.add_block'
+    plain = _('A block has been added for position #{posid}.')
+
+
+@log_entry_types.new()
+class OrderChangedBlockRemoved(OrderPositionChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.remove_block'
+    plain = _('A block has been removed for position #{posid}.')
+
+
+@log_entry_types.new()
+class OrderChangedSplit(OrderChangeLogEntryType):
+    action_type = 'pretix.event.order.changed.split'
+
+    def display_prefixed(self, event: Event, logentry: LogEntry, data):
         old_item = str(event.items.get(pk=data['old_item']))
         if data['old_variation']:
             old_item += ' - ' + str(ItemVariation.objects.get(pk=data['old_variation']))
@@ -198,194 +282,144 @@ def _display_order_changed(event: Event, logentry: LogEntry):
             'organizer': event.organizer.slug,
             'code': data['new_order']
         })
-        return mark_safe(escape(text) + ' ' + _('Position #{posid} ({old_item}, {old_price}) split into new order: {order}').format(
+        return mark_safe(self.prefix + ' ' + _('Position #{posid} ({old_item}, {old_price}) split into new order: {order}').format(
             old_item=escape(old_item),
             posid=data.get('positionid', '?'),
             order='<a href="{}">{}</a>'.format(url, data['new_order']),
             old_price=money_filter(Decimal(data['old_price']), event.currency),
         ))
-    elif logentry.action_type == 'pretix.event.order.changed.split_from':
+
+
+@log_entry_types.new()
+class OrderChangedSplitFrom(OrderLogEntryType):
+    action_type = 'pretix.event.order.changed.split_from'
+
+    def display(self, logentry: LogEntry, data):
         return _('This order has been created by splitting the order {order}').format(
             order=data['original_order'],
         )
 
 
-def _display_checkin(event, logentry):
-    data = logentry.parsed_data
+@log_entry_types.new_from_dict({
+    'pretix.event.checkin.unknown': (
+        _('Unknown scan of code "{barcode}…" at {datetime} for list "{list}", type "{type}".'),
+        _('Unknown scan of code "{barcode}…" for list "{list}", type "{type}".'),
+    ),
+    'pretix.event.checkin.revoked': (
+        _('Scan of revoked code "{barcode}…" at {datetime} for list "{list}", type "{type}", was uploaded.'),
+        _('Scan of revoked code "{barcode}" for list "{list}", type "{type}", was uploaded.'),
+    ),
+    'pretix.event.checkin.denied': (
+        _('Denied scan of position #{posid} at {datetime} for list "{list}", type "{type}", error code "{errorcode}".'),
+        _('Denied scan of position #{posid} for list "{list}", type "{type}", error code "{errorcode}".'),
+    ),
+    'pretix.control.views.checkin.reverted': _('The check-in of position #{posid} on list "{list}" has been reverted.'),
+    'pretix.event.checkin.reverted': _('The check-in of position #{posid} on list "{list}" has been reverted.'),
+})
+class CheckinErrorLogEntryType(OrderLogEntryType):
+    def display(self, logentry: LogEntry, data):
+        self.display_plain(self.plain, logentry, data)
 
-    show_dt = False
-    if 'datetime' in data:
-        dt = dateutil.parser.parse(data.get('datetime'))
-        show_dt = abs((logentry.datetime - dt).total_seconds()) > 5 or 'forced' in data
-        tz = event.timezone
-        dt_formatted = date_format(dt.astimezone(tz), "SHORT_DATETIME_FORMAT")
+    def display_plain(self, plain, logentry: LogEntry, data):
+        if isinstance(plain, tuple):
+            plain_with_dt, plain_without_dt = plain
+        else:
+            plain_with_dt, plain_without_dt = plain, plain
 
-    if 'list' in data:
-        try:
-            checkin_list = event.checkin_lists.get(pk=data.get('list')).name
-        except CheckinList.DoesNotExist:
-            checkin_list = _("(unknown)")
-    else:
-        checkin_list = _("(unknown)")
+        data = defaultdict(lambda: '?', data)
 
-    if logentry.action_type == 'pretix.event.checkin.unknown':
-        if show_dt:
-            return _(
-                'Unknown scan of code "{barcode}…" at {datetime} for list "{list}", type "{type}".'
-            ).format(
-                posid=data.get('positionid'),
-                type=data.get('type'),
-                barcode=data.get('barcode')[:16],
-                datetime=dt_formatted,
-                list=checkin_list
+        event = logentry.event
+
+        if 'list' in data:
+            try:
+                data['list'] = event.checkin_lists.get(pk=data.get('list')).name
+            except CheckinList.DoesNotExist:
+                data['list'] = _("(unknown)")
+        else:
+            data['list'] = _("(unknown)")
+
+        data['barcode'] = data.get('barcode')[:16]
+        data['posid'] = logentry.parsed_data.get('positionid', '?')
+
+        if 'datetime' in data:
+            dt = dateutil.parser.parse(data.get('datetime'))
+            if abs((logentry.datetime - dt).total_seconds()) > 5 or 'forced' in data:
+                tz = event.timezone
+                data['datetime'] = date_format(dt.astimezone(tz), "SHORT_DATETIME_FORMAT")
+                return str(plain_with_dt).format_map(data)
+            else:
+                return str(plain_without_dt).format_map(data)
+
+
+class CheckinLogEntryType(CheckinErrorLogEntryType):
+    def display(self, logentry: LogEntry, data):
+        if data.get('type') == Checkin.TYPE_EXIT:
+            return self.display_plain((
+                _('Position #{posid} has been checked out at {datetime} for list "{list}".'),
+                _('Position #{posid} has been checked out for list "{list}".'),
+            ), logentry, data)
+        elif data.get('first'):
+            return self.display_plain((
+                _('Position #{posid} has been checked in at {datetime} for list "{list}".'),
+                _('Position #{posid} has been checked in for list "{list}".'),
+            ), logentry, data)
+        elif data.get('forced'):
+            return self.display_plain(
+                _('A scan for position #{posid} at {datetime} for list "{list}" has been uploaded even though it has '
+                  'been scanned already.'),
+                logentry, data
             )
         else:
-            return _(
-                'Unknown scan of code "{barcode}…" for list "{list}", type "{type}".'
-            ).format(
-                posid=data.get('positionid'),
-                type=data.get('type'),
-                barcode=data.get('barcode')[:16],
-                list=checkin_list
+            return self.display_plain(
+                _('Position #{posid} has been scanned and rejected because it has already been scanned before '
+                  'on list "{list}".'),
+                logentry, data
             )
 
-    if logentry.action_type == 'pretix.event.checkin.revoked':
-        if show_dt:
-            return _(
-                'Scan scan of revoked code "{barcode}…" at {datetime} for list "{list}", type "{type}", was uploaded.'
-            ).format(
-                posid=data.get('positionid'),
-                type=data.get('type'),
-                barcode=data.get('barcode')[:16],
-                datetime=dt_formatted,
-                list=checkin_list
-            )
-        else:
-            return _(
-                'Scan of revoked code "{barcode}" for list "{list}", type "{type}", was uploaded.'
-            ).format(
-                posid=data.get('positionid'),
-                type=data.get('type'),
-                barcode=data.get('barcode')[:16],
-                list=checkin_list
-            )
 
-    if logentry.action_type == 'pretix.event.checkin.denied':
-        if show_dt:
-            return _(
-                'Denied scan of position #{posid} at {datetime} for list "{list}", type "{type}", '
-                'error code "{errorcode}".'
-            ).format(
-                posid=data.get('positionid'),
-                type=data.get('type'),
-                errorcode=data.get('errorcode'),
-                datetime=dt_formatted,
-                list=checkin_list
-            )
-        else:
-            return _(
-                'Denied scan of position #{posid} for list "{list}", type "{type}", error code "{errorcode}".'
-            ).format(
-                posid=data.get('positionid'),
-                type=data.get('type'),
-                errorcode=data.get('errorcode'),
-                list=checkin_list
-            )
+class OrderConsentLogEntryType(OrderLogEntryType):
+    action_type = 'pretix.event.order.consent'
 
-    if data.get('type') == Checkin.TYPE_EXIT:
-        if show_dt:
-            return _('Position #{posid} has been checked out at {datetime} for list "{list}".').format(
-                posid=data.get('positionid'),
-                datetime=dt_formatted,
-                list=checkin_list
-            )
+    def display(self, logentry: LogEntry, data):
+        return _('The user confirmed the following message: "{}"').format(
+            bleach.clean(data.get('msg'), tags=set(), strip=True)
+        )
+
+
+class OrderCanceledLogEntryType(OrderLogEntryType):
+    action_type = 'pretix.event.order.canceled'
+
+    def display(self, logentry: LogEntry, data):
+        comment = data.get('comment')
+        if comment:
+            return _('The order has been canceled (comment: "{comment}").').format(comment=comment)
         else:
-            return _('Position #{posid} has been checked out for list "{list}".').format(
-                posid=data.get('positionid'),
-                list=checkin_list
-            )
-    if data.get('first'):
-        if show_dt:
-            return _('Position #{posid} has been checked in at {datetime} for list "{list}".').format(
-                posid=data.get('positionid'),
-                datetime=dt_formatted,
-                list=checkin_list
-            )
-        else:
-            return _('Position #{posid} has been checked in for list "{list}".').format(
-                posid=data.get('positionid'),
-                list=checkin_list
-            )
-    else:
-        if data.get('forced'):
-            return _(
-                'A scan for position #{posid} at {datetime} for list "{list}" has been uploaded even though it has '
-                'been scanned already.'.format(
-                    posid=data.get('positionid'),
-                    datetime=dt_formatted,
-                    list=checkin_list
-                )
-            )
-        return _(
-            'Position #{posid} has been scanned and rejected because it has already been scanned before '
-            'on list "{list}".'.format(
-                posid=data.get('positionid'),
-                list=checkin_list
-            )
+            return _('The order has been canceled.')
+
+
+class OrderPrintLogEntryType(OrderLogEntryType):
+    action_type = 'pretix.event.order.print'
+
+    def display(self, logentry: LogEntry, data):
+        return _('Position #{posid} has been printed at {datetime} with type "{type}".').format(
+            posid=data.get('positionid'),
+            datetime=date_format(
+                dateutil.parser.parse(data["datetime"]).astimezone(logentry.event.timezone),
+                "SHORT_DATETIME_FORMAT"
+            ),
+            type=dict(PrintLog.PRINT_TYPES)[data["type"]],
         )
 
 
 @receiver(signal=logentry_display, dispatch_uid="pretixcontrol_logentry_display")
 def pretixcontrol_logentry_display(sender: Event, logentry: LogEntry, **kwargs):
 
-    if logentry.action_type.startswith('pretix.event.order.changed'):
-        return _display_order_changed(sender, logentry)
-
     if logentry.action_type.startswith('pretix.event.payment.provider.'):
         return _('The settings of a payment provider have been changed.')
 
     if logentry.action_type.startswith('pretix.event.tickets.provider.'):
         return _('The settings of a ticket output provider have been changed.')
 
-    if logentry.action_type == 'pretix.event.order.consent':
-        return _('The user confirmed the following message: "{}"').format(
-            bleach.clean(logentry.parsed_data.get('msg'), tags=set(), strip=True)
-        )
-
-    if logentry.action_type == 'pretix.event.order.canceled':
-        comment = logentry.parsed_data.get('comment')
-        if comment:
-            return _('The order has been canceled (comment: "{comment}").').format(comment=comment)
-        else:
-            return _('The order has been canceled.')
-
-    if logentry.action_type in ('pretix.control.views.checkin.reverted', 'pretix.event.checkin.reverted'):
-        if 'list' in logentry.parsed_data:
-            try:
-                checkin_list = sender.checkin_lists.get(pk=logentry.parsed_data.get('list')).name
-            except CheckinList.DoesNotExist:
-                checkin_list = _("(unknown)")
-        else:
-            checkin_list = _("(unknown)")
-
-        return _('The check-in of position #{posid} on list "{list}" has been reverted.').format(
-            posid=logentry.parsed_data.get('positionid'),
-            list=checkin_list,
-        )
-
-    if sender and logentry.action_type.startswith('pretix.event.checkin'):
-        return _display_checkin(sender, logentry)
-
-    if logentry.action_type == 'pretix.event.order.print':
-        return _('Position #{posid} has been printed at {datetime} with type "{type}".').format(
-            posid=logentry.parsed_data.get('positionid'),
-            datetime=date_format(
-                dateutil.parser.parse(logentry.parsed_data["datetime"]).astimezone(sender.timezone),
-                "SHORT_DATETIME_FORMAT"
-            ),
-            type=dict(PrintLog.PRINT_TYPES)[logentry.parsed_data["type"]],
-        )
-
 
 @receiver(signal=orderposition_blocked_display, dispatch_uid="pretixcontrol_orderposition_blocked_display")
 def pretixcontrol_orderposition_blocked_display(sender: Event, orderposition, block_name, **kwargs):
@@ -396,6 +430,7 @@ def pretixcontrol_orderposition_blocked_display(sender: Event, orderposition, bl
 
 
 @log_entry_types.new_from_dict({
+    'pretix.event.order.deleted': _('The test mode order {code} has been deleted.'),
     'pretix.event.order.modified': _('The order details have been changed.'),
     'pretix.event.order.unpaid': _('The order has been marked as unpaid.'),
     'pretix.event.order.secret.changed': _('The order\'s secret has been changed.'),
@@ -486,17 +521,16 @@ class VoucherRedeemedLogEntryType(VoucherLogEntryType):
     action_type = 'pretix.voucher.redeemed'
     plain = _('The voucher has been redeemed in order {order_code}.')
 
-    def display(self, logentry):
-        data = json.loads(logentry.data)
-        data = defaultdict(lambda: '?', data)
+    def display(self, logentry, data):
         url = reverse('control:event.order', kwargs={
             'event': logentry.event.slug,
             'organizer': logentry.event.organizer.slug,
-            'code': data['order_code']
+            'code': data.get('order_code', '?')
         })
-        return mark_safe(self.plain.format(
-            order_code='<a href="{}">{}</a>'.format(url, data['order_code']),
-        ))
+        return format_html(
+            self.plain,
+            order_code=format_html('<a href="{}">{}</a>', url, data('order_code', '?')),
+        )
 
 
 @log_entry_types.new_from_dict({
@@ -519,8 +553,8 @@ class CoreTaxRuleLogEntryType(TaxRuleLogEntryType):
 
 
 class TeamMembershipLogEntryType(LogEntryType):
-    def display(self, logentry):
-        return self.plain.format(user=logentry.parsed_data.get('email'))
+    def display(self, logentry, data):
+        return self.plain.format(user=data.get('email'))
 
 
 @log_entry_types.new_from_dict({
@@ -537,9 +571,9 @@ class CoreTeamMembershipLogEntryType(TeamMembershipLogEntryType):
 class TeamMemberJoinedLogEntryType(LogEntryType):
     action_type = 'pretix.team.member.joined'
 
-    def display(self, logentry):
+    def display(self, logentry, data):
         return _('{user} has joined the team using the invite sent to {email}.').format(
-            user=logentry.parsed_data.get('email'), email=logentry.parsed_data.get('invite_email')
+            user=data.get('email'), email=data.get('invite_email')
         )
 
 
@@ -547,23 +581,23 @@ class TeamMemberJoinedLogEntryType(LogEntryType):
 class UserSettingsChangedLogEntryType(LogEntryType):
     action_type = 'pretix.user.settings.changed'
 
-    def display(self, logentry):
+    def display(self, logentry, data):
         text = str(_('Your account settings have been changed.'))
-        if 'email' in logentry.parsed_data:
+        if 'email' in data:
             text = text + ' ' + str(
-                _('Your email address has been changed to {email}.').format(email=logentry.parsed_data['email']))
-        if 'new_pw' in logentry.parsed_data:
+                _('Your email address has been changed to {email}.').format(email=data['email']))
+        if 'new_pw' in data:
             text = text + ' ' + str(_('Your password has been changed.'))
-        if logentry.parsed_data.get('is_active') is True:
+        if data.get('is_active') is True:
             text = text + ' ' + str(_('Your account has been enabled.'))
-        elif logentry.parsed_data.get('is_active') is False:
+        elif data.get('is_active') is False:
             text = text + ' ' + str(_('Your account has been disabled.'))
         return text
 
 
 class UserImpersonatedLogEntryType(LogEntryType):
-    def display(self, logentry):
-        return self.plain.format(logentry.parsed_data['other_email'])
+    def display(self, logentry, data):
+        return self.plain.format(data['other_email'])
 
 
 @log_entry_types.new_from_dict({
@@ -688,16 +722,13 @@ class CoreLogEntryType(LogEntryType):
 
 
 @log_entry_types.new_from_dict({
-    'pretix.event.order.deleted': _('The test mode order {code} has been deleted.'),
     'pretix.event.item_meta_property.added': _('A meta property has been added to this event.'),
     'pretix.event.item_meta_property.deleted': _('A meta property has been removed from this event.'),
     'pretix.event.item_meta_property.changed': _('A meta property has been changed on this event.'),
-    'pretix.event.checkinlist.added': _('The check-in list has been added.'),
-    'pretix.event.checkinlist.deleted': _('The check-in list has been deleted.'),
-    'pretix.event.checkinlists.deleted': _('The check-in list has been deleted.'),  # backwards compatibility
-    'pretix.event.checkinlist.changed': _('The check-in list has been changed.'),
     'pretix.event.settings': _('The event settings have been changed.'),
     'pretix.event.tickets.settings': _('The ticket download settings have been changed.'),
+    'pretix.event.tickets.provider': _('The settings of a ticket output provider have been changed.'),
+    'pretix.event.payment.provider': _('The settings of a payment provider have been changed.'),
     'pretix.event.live.activated': _('The shop has been taken live.'),
     'pretix.event.live.deactivated': _('The shop has been taken offline.'),
     'pretix.event.testmode.activated': _('The shop has been taken into test mode.'),
@@ -717,6 +748,19 @@ class CoreEventLogEntryType(EventLogEntryType):
     pass
 
 
+@log_entry_types.new_from_dict({
+    'pretix.event.checkinlist.added': _('The check-in list has been added.'),
+    'pretix.event.checkinlist.deleted': _('The check-in list has been deleted.'),
+    'pretix.event.checkinlists.deleted': _('The check-in list has been deleted.'),  # backwards compatibility
+    'pretix.event.checkinlist.changed': _('The check-in list has been changed.'),
+})
+class CheckinlistLogEntryType(EventLogEntryType):
+    object_link_wrapper = _('Check-in list {val}')
+    object_link_viewname = 'control:event.orders.checkinlists.edit'
+    object_link_argname = 'list'
+    content_type = CheckinList
+
+
 @log_entry_types.new_from_dict({
     'pretix.event.plugins.enabled': _('The plugin has been enabled.'),
     'pretix.event.plugins.disabled': _('The plugin has been disabled.'),
@@ -724,7 +768,7 @@ class CoreEventLogEntryType(EventLogEntryType):
 class EventPluginStateLogEntryType(EventLogEntryType):
     object_link_wrapper = _('Plugin {val}')
 
-    def get_object_link_info(self, logentry) -> dict:
+    def get_object_link_info(self, logentry) -> Optional[dict]:
         if 'plugin' in logentry.parsed_data:
             app = app_cache.get(logentry.parsed_data['plugin'])
             if app and hasattr(app, 'PretixPluginMeta'):
@@ -759,17 +803,17 @@ class CoreItemLogEntryType(ItemLogEntryType):
     'pretix.event.item.variation.changed': _('The variation "{value}" has been changed.'),
 })
 class VariationLogEntryType(ItemLogEntryType):
-    def display(self, logentry):
-        if 'value' not in logentry.parsed_data:
+    def display(self, logentry, data):
+        if 'value' not in data:
             # Backwards compatibility
-            var = ItemVariation.objects.filter(id=logentry.parsed_data['id']).first()
+            var = ItemVariation.objects.filter(id=data['id']).first()
             if var:
-                logentry.parsed_data['value'] = str(var.value)
+                data['value'] = str(var.value)
             else:
-                logentry.parsed_data['value'] = '?'
+                data['value'] = '?'
         else:
-            logentry.parsed_data['value'] = LazyI18nString(logentry.parsed_data['value'])
-        return super().display(logentry)
+            data['value'] = LazyI18nString(data['value'])
+        return super().display(logentry, data)
 
 
 @log_entry_types.new_from_dict({
@@ -825,27 +869,27 @@ class CoreDiscountLogEntryType(DiscountLogEntryType):
 class LegacyCheckinLogEntryType(OrderLogEntryType):
     action_type = 'pretix.control.views.checkin'
 
-    def display(self, logentry):
+    def display(self, logentry, data):
         # deprecated
-        dt = dateutil.parser.parse(logentry.parsed_data.get('datetime'))
+        dt = dateutil.parser.parse(data.get('datetime'))
         tz = logentry.event.timezone
         dt_formatted = date_format(dt.astimezone(tz), "SHORT_DATETIME_FORMAT")
-        if 'list' in logentry.parsed_data:
+        if 'list' in data:
             try:
-                checkin_list = logentry.event.checkin_lists.get(pk=logentry.parsed_data.get('list')).name
+                checkin_list = logentry.event.checkin_lists.get(pk=data.get('list')).name
             except CheckinList.DoesNotExist:
                 checkin_list = _("(unknown)")
         else:
             checkin_list = _("(unknown)")
 
-        if logentry.parsed_data.get('first'):
+        if data.get('first'):
             return _('Position #{posid} has been checked in manually at {datetime} on list "{list}".').format(
-                posid=logentry.parsed_data.get('positionid'),
+                posid=data.get('positionid'),
                 datetime=dt_formatted,
                 list=checkin_list,
             )
         return _('Position #{posid} has been checked in again at {datetime} on list "{list}".').format(
-            posid=logentry.parsed_data.get('positionid'),
+            posid=data.get('positionid'),
             datetime=dt_formatted,
             list=checkin_list
         )

src/pretix/control/views/event.py

@@ -491,8 +491,11 @@ class PaymentProviderSettings(EventSettingsViewMixin, EventPermissionRequiredMix
         if self.form.is_valid():
             if self.form.has_changed():
                 self.request.event.log_action(
-                    'pretix.event.payment.provider.' + self.provider.identifier, user=self.request.user, data={
-                        k: self.form.cleaned_data.get(k) for k in self.form.changed_data
+                    'pretix.event.payment.provider', user=self.request.user, data={
+                        'provider': self.provider.identifier,
+                        'new_values': {
+                            k: self.form.cleaned_data.get(k) for k in self.form.changed_data
+                        }
                     }
                 )
                 self.form.save()
@@ -888,11 +891,14 @@ class TicketSettings(EventSettingsViewMixin, EventPermissionRequiredMixin, FormV
                 provider.form.save()
                 if provider.form.has_changed():
                     self.request.event.log_action(
-                        'pretix.event.tickets.provider.' + provider.identifier, user=self.request.user, data={
-                            k: (provider.form.cleaned_data.get(k).name
-                                if isinstance(provider.form.cleaned_data.get(k), File)
-                                else provider.form.cleaned_data.get(k))
-                            for k in provider.form.changed_data
+                        'pretix.event.tickets.provider', user=self.request.user, data={
+                            'provider': provider.identifier,
+                            'new_values': {
+                                k: (provider.form.cleaned_data.get(k).name
+                                    if isinstance(provider.form.cleaned_data.get(k), File)
+                                    else provider.form.cleaned_data.get(k))
+                                for k in provider.form.changed_data
+                            }
                         }
                     )
                     tickets.invalidate_cache.apply_async(kwargs={'event': self.request.event.pk, 'provider': provider.identifier})

src/pretix/control/views/main.py

@@ -313,7 +313,7 @@ class EventWizard(SafeSessionWizardView):
                     )
                 event.set_defaults()
 
-            if basics_data['tax_rate']:
+            if basics_data['tax_rate'] is not None:
                 if not event.settings.tax_rate_default or event.settings.tax_rate_default.rate != basics_data['tax_rate']:
                     event.settings.tax_rate_default = event.tax_rules.create(
                         name=LazyI18nString.from_gettext(gettext('VAT')),