Always base64-encode email attachments (Z#23242540)

It might sound unneccesary to base64-encode plaintext attachments, but some smtp providers modify them otherwise

doc/api/resources/checkin.rst

@@ -71,6 +71,8 @@ Checking a ticket in
    :>json object questions: List of questions to be answered for check-in, only set on status ``"incomplete"``.
    :>json object media_policy: Reusable media policy (see documentation on items), only set on status ``"exchange"``.
    :>json object media_type: Reusable media type (see documentation on items), only set on status ``"exchange"``.
+   :>json boolean simulate: Do not actually perform the check-in, only simulate the response. The ``position`` response
+                            object will not reflect the simulated changes.
 
    **Example request**:
 

doc/api/resources/orders.rst

@@ -2038,7 +2038,7 @@ Manipulating individual positions
 
    * ``order`` (mandatory, specified as a string mapping to a ``code``)
 
-   * ``addon_to`` (optional, specified as an integer mapping to the ``positionid`` of the parent position)
+   * ``addon_to`` (optional, specified as an integer mapping to ``positionid`` - the number of the position within the order, see :ref:`_order-position-resource` - of the parent position)
 
    * ``item`` (mandatory)
 
@@ -2348,7 +2348,7 @@ otherwise, such as splitting an order or changing fees.
             "subevent": 562,
             "seat": "seat-guid-2",
             "price": "99.99",
-            "addon_to": 12374,
+            "addon_to": 1,
             "attendee_name": "Peter",
           }
         ],

src/pretix/api/auth/devicesecurity.py

@@ -115,7 +115,7 @@ class PretixScanSecurityProfile(AllowListSecurityProfile):
         ('GET', 'api-v1:event.settings'),
         ('POST', 'api-v1:upload'),
         ('POST', 'api-v1:checkinrpc.redeem'),
-        ('POST', 'api-v1:checkinrpc.annull'),
+        ('POST', 'api-v1:checkinrpc.annul'),
         ('GET', 'api-v1:checkinrpc.search'),
         ('GET', 'api-v1:reusablemedium-list'),
         ('POST', 'api-v1:reusablemedium-lookup'),
@@ -154,7 +154,7 @@ class PretixScanNoSyncNoSearchSecurityProfile(AllowListSecurityProfile):
         ('GET', 'api-v1:event.settings'),
         ('POST', 'api-v1:upload'),
         ('POST', 'api-v1:checkinrpc.redeem'),
-        ('POST', 'api-v1:checkinrpc.annull'),
+        ('POST', 'api-v1:checkinrpc.annul'),
         ('GET', 'api-v1:checkinrpc.search'),
     )
 
@@ -191,7 +191,7 @@ class PretixScanNoSyncSecurityProfile(AllowListSecurityProfile):
         ('GET', 'api-v1:event.settings'),
         ('POST', 'api-v1:upload'),
         ('POST', 'api-v1:checkinrpc.redeem'),
-        ('POST', 'api-v1:checkinrpc.annull'),
+        ('POST', 'api-v1:checkinrpc.annul'),
         ('GET', 'api-v1:checkinrpc.search'),
     )
 

src/pretix/api/serializers/checkin.py

@@ -90,6 +90,7 @@ class CheckinRPCRedeemInputSerializer(serializers.Serializer):
     answers = serializers.JSONField(required=False, allow_null=True)
     exchange_medium_type = serializers.ChoiceField(required=False, choices=MEDIA_TYPES)
     exchange_medium_identifier = serializers.CharField(required=False)
+    simulate = serializers.BooleanField(default=False, required=False)
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)

src/pretix/api/views/checkin.py

@@ -839,6 +839,11 @@ def _redeem_process(*, checkinlists, raw_barcode, answers_data, datetime, force,
             )
 
             if exchange_medium_identifier:  # other fields are filled, see CheckinRPCRedeemInputSerializer.validate
+                if simulate:
+                    raise CheckInError(
+                        gettext('You cannot simulate a medium exchange.'),
+                        'error'
+                    )
                 with transaction.atomic():
                     # Do exchange and check-in atomically, i.e. both succeed or both fail
                     medium = perform_media_exchange(
@@ -1066,6 +1071,7 @@ class CheckinRPCRedeemView(views.APIView):
             legacy_url_support=False,
             exchange_medium_type=s.validated_data.get('exchange_medium_type'),
             exchange_medium_identifier=s.validated_data.get('exchange_medium_identifier'),
+            simulate=s.validated_data.get('simulate'),
         )
 
 

src/pretix/base/forms/widgets.py

@@ -314,3 +314,18 @@ class BusinessBooleanRadio(forms.RadioSelect):
             'False': False,
             False: False,
         }.get(value)
+
+
+class OptionAttrsSelect(forms.Select):
+    def __init__(self, *args, option_attrs=None, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.option_attrs = option_attrs or {}
+
+    def create_option(self, name, value, label, selected, index, subindex=None, attrs=None):
+        option = super().create_option(
+            name, value, label, selected, index, subindex=subindex, attrs=attrs
+        )
+        extra = self.option_attrs.get(str(value))
+        if extra:
+            option["attrs"].update(extra)
+        return option

src/pretix/base/reldate.py

@@ -19,30 +19,245 @@
 # 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/>.
 #
+import copy
 import datetime
+import os
+import warnings
 from collections import namedtuple
-from typing import Union
+from dataclasses import dataclass
+from typing import (
+    TYPE_CHECKING, Iterable, List, Literal, Optional, Tuple, Union, cast,
+)
 from zoneinfo import ZoneInfo
 
 from dateutil import parser
 from django import forms
 from django.core.exceptions import ValidationError
 from django.db import models
+from django.forms.widgets import Widget
 from django.utils.formats import get_format
-from django.utils.functional import lazy
+from django.utils.functional import Promise, lazy
 from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _
 from rest_framework import serializers
 
-BASE_CHOICES = (
-    ('date_from', _('Event start')),
-    ('date_to', _('Event end')),
-    ('date_admission', _('Event admission')),
-    ('presale_start', _('Presale start')),
-    ('presale_end', _('Presale end')),
-)
+from pretix.base.forms.widgets import OptionAttrsSelect
 
-RelativeDate = namedtuple('RelativeDate', ['days', 'minutes', 'time', 'is_after', 'base_date_name'], defaults=(0, None, None, False, 'date_from'))
+if TYPE_CHECKING:
+    from .models import Event, Order, SubEvent
+
+
+@dataclass(frozen=True)
+class BaseChoice:
+    base: Literal["event", "order"]
+    attribute: str
+    text: Promise
+    supports_before: bool
+    supports_after: bool
+
+    @property
+    def key(self) -> str:
+        key = f"{self.base}__{self.attribute}"
+        return key
+
+    @staticmethod
+    def find(objects: Iterable["BaseChoice"], key: str) -> "BaseChoice":
+        if "__" in key:
+            choice = next((obj for obj in objects if obj.key == key), None)
+        else:
+            # fallback for RelativeDateFields stored, before support for bases other than event was added
+            choice = next((obj for obj in objects if obj.attribute == key and obj.base == "event"), None)
+
+        if choice is None:
+            raise TypeError(f"key {key} must be a valid key in BASE_CHOICES")
+
+        return choice
+
+
+BASE_CHOICES: List[BaseChoice] = [
+    BaseChoice('event', 'date_from', _('Event start'), True, True),
+    BaseChoice('event', 'date_to', _('Event end'), True, True),
+    BaseChoice('event', 'date_admission', _('Event admission'), True, True),
+    BaseChoice('event', 'presale_start', _('Presale start'), True, True),
+    BaseChoice('event', 'presale_end', _('Presale end'), True, True),
+    BaseChoice('order', 'datetime', _('Order creation'), False, True),
+    BaseChoice('order', 'expires', _('Order expiry'), True, True),
+]
+
+EVENT_BASE_CHOICES = [
+    x for x in BASE_CHOICES if x.base == 'event'
+]
+
+ORDER_BASE_CHOICES = [
+    x for x in BASE_CHOICES if x.base == 'order'
+]
+
+
+@dataclass(frozen=True)
+class RelativeDate:
+    """
+    This contains information on a date that is defined in relation to a fixed base point.
+    This means that the underlying data is a fixed date as the base point and a number of days or a time interval
+    to calculate the date.
+
+    The list of valid base date choices is defined in BASE_CHOICES.
+    If the base_date_name is not set, the date_from attribute of Event is used.
+    """
+
+    days: int = 0
+    minutes: Optional[int] = None
+    time: Optional[datetime.time] = None
+    is_after: bool = False
+    base_date_name: str = 'event__date_from__'
+
+    def __post_init__(self) -> None:
+        if self.is_after and not self._choice.supports_after:
+            raise ValueError(
+                "The selected base date and attribute combination does not support relative dates placed after the base date"
+            )
+        if not self.is_after and not self._choice.supports_before:
+            raise ValueError(
+                "The selected base date and attribute combination does not support relative dates placed before the base date")
+
+    @property
+    def _choice(self):
+        return BaseChoice.find(BASE_CHOICES, self.base_date_name)
+
+    @property
+    def key(self):
+        return self._choice.key
+
+    def __eq__(self, o: object) -> bool:
+        if not isinstance(o, RelativeDate):
+            return False
+        return self.to_string() == o.to_string()
+
+    def _resolve_date(self, base: "Event | Order | SubEvent") -> Tuple[datetime.datetime, ZoneInfo]:
+        """
+        Resolves the datetime and timezone information of this RelativeDate object in relation to the provided reference.
+
+        :param base: the reference which should be used to resolve the relative date
+        :return:
+        """
+        from .models import Event, Order, SubEvent
+
+        choice = self._choice
+
+        if choice.base == "order" and isinstance(base, Order):
+            event = base.event
+            base_date = getattr(base, choice.attribute)
+        elif choice.base == "event" and isinstance(base, SubEvent):
+            event = base.event
+            base_date = (getattr(base, choice.attribute) or
+                         getattr(base.event, choice.attribute) or
+                         base.date_from)
+        elif choice.base == "event" and isinstance(base, Event):
+            event = base
+            base_date = getattr(base, choice.attribute) or event.date_from
+        else:
+            raise TypeError("The base defined by data does not match the passed in base")
+
+        tz = ZoneInfo(event.settings.timezone)
+        return base_date, tz
+
+    def date(self, base: "Event | Order | SubEvent") -> datetime.date:
+        """
+        Resolves the effective date of this RelativeDate object in relation to the provided reference.
+
+        :param base: the reference which should be used to resolve the date
+        :return: datetime.date
+        """
+        if self.minutes is not None:
+            raise ValueError('A minute-based relative datetime can not be used as a date')
+
+        base_date, tz = self._resolve_date(base)
+
+        if self.is_after:
+            new_date = base_date.astimezone(tz) + datetime.timedelta(days=self.days)
+        else:
+            new_date = base_date.astimezone(tz) - datetime.timedelta(days=self.days)
+        return new_date.date()
+
+    def datetime(self, base: "Event | Order | SubEvent") -> datetime.datetime:
+        """
+        Resolves the effective datetime of this RelativeDate object in relation to the provided reference.
+
+        :param base: the reference which should be used to resolve the datetime
+        :return: datetime.datetime
+        """
+        base_date, tz = self._resolve_date(base)
+
+        if self.minutes is not None:
+            if self.is_after:
+                return base_date.astimezone(tz) + datetime.timedelta(minutes=self.minutes)
+            else:
+                return base_date.astimezone(tz) - datetime.timedelta(minutes=self.minutes)
+        else:
+            if self.is_after:
+                new_date = (base_date.astimezone(tz) + datetime.timedelta(days=self.days)).astimezone(tz)
+            else:
+                new_date = (base_date.astimezone(tz) - datetime.timedelta(days=self.days)).astimezone(tz)
+            if self.time:
+                new_date = new_date.replace(
+                    hour=self.time.hour,
+                    minute=self.time.minute,
+                    second=self.time.second
+                )
+            new_date = new_date.astimezone(tz)
+            return new_date
+
+    def to_string(self) -> str:
+        if self.minutes is not None:
+            return 'RELDATE/minutes/{}/{}/{}'.format(  #
+                self.minutes,
+                self._choice.key,
+                'after' if self.is_after else '',
+            )
+        return 'RELDATE/{}/{}/{}/{}'.format(  #
+            self.days,
+            self.time.strftime('%H:%M:%S') if self.time else '-',
+            self._choice.key,
+            'after' if self.is_after else '',
+        )
+
+    @classmethod
+    def from_string(cls, input: str):
+        if not input.startswith('RELDATE/'):
+            raise TypeError("Invalid input for RelativeDate.from_string()")
+
+        parts = input.split('/')
+        if parts[1] == 'minutes':
+            data = RelativeDate(
+                days=0,
+                minutes=int(parts[2]),
+                base_date_name=parts[3],
+                time=None,
+                is_after=len(parts) > 4 and parts[4] == "after",
+            )
+        else:
+            if parts[2] == '-':
+                time = None
+            else:
+                timeparts = parts[2].split(':')
+                time = datetime.time(hour=int(timeparts[0]), minute=int(timeparts[1]), second=int(timeparts[2]))
+            try:
+                data = RelativeDate(
+                    days=int(parts[1] or 0),
+                    base_date_name=parts[3],
+                    time=time,
+                    minutes=None,
+                    is_after=len(parts) > 4 and parts[4] == "after",
+                )
+            except ValueError:
+                data = RelativeDate(
+                    days=0,
+                    base_date_name=parts[3],
+                    time=time,
+                    minutes=None,
+                    is_after=len(parts) > 4 and parts[4] == "after",
+                )
+
+        return data
 
 
 class RelativeDateWrapper:
@@ -50,130 +265,53 @@ class RelativeDateWrapper:
     This contains information on a date that might be relative to an event. This means
     that the underlying data is either a fixed date or a number of days and a wall clock
     time to calculate the date based on a base point.
-
-    The base point can be the date_from, date_to, date_admission, presale_start or presale_end
-    attribute of an event or subevent. If the respective attribute is not set, ``date_from``
-    will be used.
     """
 
     def __init__(self, data: Union[datetime.datetime, RelativeDate]):
         self.data = data
 
-    def date(self, event) -> datetime.date:
-        from .models import SubEvent
+    def date(self, base: "Event | Order | SubEvent") -> datetime.date:
+        """
+        If the RelativeDateWrapper wraps a RelativeDate object:
+            Resolves the effective date of this object in relation to the provided reference.
+        If the RelativeDateWrapper wraps an absolute date or datetime:
+            Returns the wrapped absolute date.
 
+        :param base: the reference which should be used to resolve the date in case it is a relative date.
+        :return: datetime.date
+        """
         if isinstance(self.data, datetime.datetime):
             return self.data.date()
         elif isinstance(self.data, datetime.date):
             return self.data
         else:
-            if self.data.minutes is not None:
-                raise ValueError('A minute-based relative datetime can not be used as a date')
+            return self.data.date(base)
 
-            tz = ZoneInfo(event.settings.timezone)
-            if isinstance(event, SubEvent):
-                base_date = (
-                    getattr(event, self.data.base_date_name)
-                    or getattr(event.event, self.data.base_date_name)
-                    or event.date_from
-                )
-            else:
-                base_date = getattr(event, self.data.base_date_name) or event.date_from
-
-            if self.data.is_after:
-                new_date = base_date.astimezone(tz) + datetime.timedelta(days=self.data.days)
-            else:
-                new_date = base_date.astimezone(tz) - datetime.timedelta(days=self.data.days)
-            return new_date.date()
-
-    def datetime(self, event) -> datetime.datetime:
-        from .models import SubEvent
+    def datetime(self, base: "Event | Order | SubEvent") -> datetime.datetime:
+        """
+        If the RelativeDateWrapper wraps a RelativeDate object:
+            Resolves the effective datetime of this object in relation to the provided reference.
+        If the RelativeDateWrapper wraps an absolute date or datetime:
+            Returns the wrapped absolute datetime.
 
+        :param base: the reference which should be used to resolve the datetime in case it is a relative datetime.
+        :return: datetime.datetime
+        """
         if isinstance(self.data, (datetime.datetime, datetime.date)):
             return self.data
         else:
-            tz = ZoneInfo(event.settings.timezone)
-            if isinstance(event, SubEvent):
-                base_date = (
-                    getattr(event, self.data.base_date_name)
-                    or getattr(event.event, self.data.base_date_name)
-                    or event.date_from
-                )
-            else:
-                base_date = getattr(event, self.data.base_date_name) or event.date_from
-
-            if self.data.minutes is not None:
-                if self.data.is_after:
-                    return base_date.astimezone(tz) + datetime.timedelta(minutes=self.data.minutes)
-                else:
-                    return base_date.astimezone(tz) - datetime.timedelta(minutes=self.data.minutes)
-            else:
-                if self.data.is_after:
-                    new_date = (base_date.astimezone(tz) + datetime.timedelta(days=self.data.days)).astimezone(tz)
-                else:
-                    new_date = (base_date.astimezone(tz) - datetime.timedelta(days=self.data.days)).astimezone(tz)
-                if self.data.time:
-                    new_date = new_date.replace(
-                        hour=self.data.time.hour,
-                        minute=self.data.time.minute,
-                        second=self.data.time.second
-                    )
-                new_date = new_date.astimezone(tz)
-                return new_date
+            return self.data.datetime(base)
 
     def to_string(self) -> str:
         if isinstance(self.data, (datetime.datetime, datetime.date)):
             return self.data.isoformat()
         else:
-            if self.data.minutes is not None:
-                return 'RELDATE/minutes/{}/{}/{}'.format(  #
-                    self.data.minutes,
-                    self.data.base_date_name,
-                    'after' if self.data.is_after else '',
-                )
-            return 'RELDATE/{}/{}/{}/{}'.format(  #
-                self.data.days,
-                self.data.time.strftime('%H:%M:%S') if self.data.time else '-',
-                self.data.base_date_name,
-                'after' if self.data.is_after else '',
-            )
+            return self.data.to_string()
 
     @classmethod
     def from_string(cls, input: str):
         if input.startswith('RELDATE/'):
-            parts = input.split('/')
-            if parts[1] == 'minutes':
-                data = RelativeDate(
-                    days=0,
-                    minutes=int(parts[2]),
-                    base_date_name=parts[3],
-                    time=None,
-                    is_after=len(parts) > 4 and parts[4] == "after",
-                )
-            else:
-                if parts[2] == '-':
-                    time = None
-                else:
-                    timeparts = parts[2].split(':')
-                    time = datetime.time(hour=int(timeparts[0]), minute=int(timeparts[1]), second=int(timeparts[2]))
-                try:
-                    data = RelativeDate(
-                        days=int(parts[1] or 0),
-                        base_date_name=parts[3],
-                        time=time,
-                        minutes=None,
-                        is_after=len(parts) > 4 and parts[4] == "after",
-                    )
-                except ValueError:
-                    data = RelativeDate(
-                        days=0,
-                        base_date_name=parts[3],
-                        time=time,
-                        minutes=None,
-                        is_after=len(parts) > 4 and parts[4] == "after",
-                    )
-            if data.base_date_name not in [k[0] for k in BASE_CHOICES]:
-                raise ValueError('{} is not a valid base date'.format(data.base_date_name))
+            data = RelativeDate.from_string(input)
         else:
             data = parser.parse(input)
         return RelativeDateWrapper(data)
@@ -187,7 +325,6 @@ BEFORE_AFTER_CHOICE = (
     ('after', _('after')),
 )
 
-
 reldatetimeparts = namedtuple('reldatetimeparts', (
     "status",  # 0
     "absolute",  # 1
@@ -202,6 +339,14 @@ reldatetimeparts = namedtuple('reldatetimeparts', (
 reldatetimeparts.indizes = reldatetimeparts(*range(9))
 
 
+def _get_choices(base_choices: List[BaseChoice]) -> List[Tuple[str, Promise]]:
+    return [(c.key, c.text) for c in base_choices]
+
+
+def _get_choice_validation_obj(choices: List[BaseChoice]):
+    return {c.key: {"data-supports-before": c.supports_before, "data-supports-after": c.supports_after} for c in choices}
+
+
 class RelativeDateTimeWidget(forms.MultiWidget):
     template_name = 'pretixbase/forms/widgets/reldatetime.html'
     parts = reldatetimeparts
@@ -209,6 +354,7 @@ class RelativeDateTimeWidget(forms.MultiWidget):
     def __init__(self, *args, **kwargs):
         self.status_choices = kwargs.pop('status_choices')
         base_choices = kwargs.pop('base_choices')
+        choices = _get_choices(base_choices)
 
         def placeholder_datetime_format():
             df = get_format('DATETIME_INPUT_FORMATS')[0]
@@ -220,21 +366,29 @@ class RelativeDateTimeWidget(forms.MultiWidget):
             tf = get_format('TIME_INPUT_FORMATS')[0]
             return datetime.time(8, 30, 0).strftime(tf)
 
-        widgets = reldatetimeparts(
+        widgets = cast(dict[str, Widget | type[Widget]], cast(object, reldatetimeparts(
             status=forms.RadioSelect(choices=self.status_choices),
             absolute=forms.DateTimeInput(
                 attrs={'placeholder': lazy(placeholder_datetime_format, str), 'class': 'datetimepicker'}
             ),
             rel_days_number=forms.NumberInput(),
-            rel_mins_relationto=forms.Select(choices=base_choices),
+            rel_mins_relationto=OptionAttrsSelect(
+                attrs={'data-relative-choice': True},
+                choices=choices,
+                option_attrs=_get_choice_validation_obj(base_choices)
+            ),
             rel_days_timeofday=forms.TimeInput(
                 attrs={'placeholder': lazy(placeholder_time_format, str), 'class': 'timepickerfield'}
             ),
             rel_mins_number=forms.NumberInput(),
-            rel_days_relationto=forms.Select(choices=base_choices),
-            rel_mins_relation=forms.Select(choices=BEFORE_AFTER_CHOICE),
-            rel_days_relation=forms.Select(choices=BEFORE_AFTER_CHOICE),
-        )
+            rel_days_relationto=OptionAttrsSelect(
+                attrs={'data-relative-choice': True},
+                choices=choices,
+                option_attrs=_get_choice_validation_obj(base_choices)
+            ),
+            rel_mins_relation=forms.Select(attrs={'data-relation-choice': True}, choices=BEFORE_AFTER_CHOICE),
+            rel_days_relation=forms.Select(attrs={'data-relation-choice': True}, choices=BEFORE_AFTER_CHOICE),
+        )))
         super().__init__(widgets=widgets, *args, **kwargs)
 
     def decompress(self, value):
@@ -247,10 +401,10 @@ class RelativeDateTimeWidget(forms.MultiWidget):
                 status="unset",
                 absolute=None,
                 rel_days_number=1,
-                rel_mins_relationto="date_from",
+                rel_mins_relationto="event__date_from",
                 rel_days_timeofday=None,
                 rel_mins_number=0,
-                rel_days_relationto="date_from",
+                rel_days_relationto="event__date_from",
                 rel_mins_relation="before",
                 rel_days_relation="before"
             )
@@ -259,10 +413,10 @@ class RelativeDateTimeWidget(forms.MultiWidget):
                 status="absolute",
                 absolute=value.data,
                 rel_days_number=1,
-                rel_mins_relationto="date_from",
+                rel_mins_relationto="event__date_from",
                 rel_days_timeofday=None,
                 rel_mins_number=0,
-                rel_days_relationto="date_from",
+                rel_days_relationto="event__date_from",
                 rel_mins_relation="before",
                 rel_days_relation="before"
             )
@@ -271,10 +425,10 @@ class RelativeDateTimeWidget(forms.MultiWidget):
                 status="relative_minutes",
                 absolute=None,
                 rel_days_number=None,
-                rel_mins_relationto=value.data.base_date_name,
+                rel_mins_relationto=value.data.key,
                 rel_days_timeofday=None,
                 rel_mins_number=value.data.minutes,
-                rel_days_relationto=value.data.base_date_name,
+                rel_days_relationto=value.data.key,
                 rel_mins_relation="after" if value.data.is_after else "before",
                 rel_days_relation="after" if value.data.is_after else "before"
             )
@@ -282,10 +436,10 @@ class RelativeDateTimeWidget(forms.MultiWidget):
             status="relative",
             absolute=None,
             rel_days_number=value.data.days,
-            rel_mins_relationto=value.data.base_date_name,
+            rel_mins_relationto=value.data.key,
             rel_days_timeofday=value.data.time,
             rel_mins_number=0,
-            rel_days_relationto=value.data.base_date_name,
+            rel_days_relationto=value.data.key,
             rel_mins_relation="after" if value.data.is_after else "before",
             rel_days_relation="after" if value.data.is_after else "before"
         )
@@ -309,17 +463,41 @@ class RelativeDateTimeField(forms.MultiValueField):
             ('relative', _('Relative date:')),
             ('relative_minutes', _('Relative time:')),
         ]
+        self.relative_to_order = kwargs.pop('relative_to_order', False)
+
+        possible_choices = copy.deepcopy(EVENT_BASE_CHOICES)
+        if self.relative_to_order:
+            possible_choices.extend(ORDER_BASE_CHOICES)
+
         if kwargs.get('limit_choices'):
             limit = kwargs.pop('limit_choices')
-            choices = [(k, v) for k, v in BASE_CHOICES if k in limit]
-        else:
-            choices = BASE_CHOICES
+            if any(["__" not in l for l in limit]):
+                _warn_skips = (str(os.path.dirname(__file__)),)
+
+                warnings.warn(
+                    message="Please prefix limit_choices with the base the attributes refer to, for example event__date_from",
+                    category=DeprecationWarning,
+                    skip_file_prefixes=_warn_skips
+                )
+
+            possible_choices = [
+                c for c in possible_choices if
+                # new base case as we want limit_choices to be expressed as base__attribute
+                (c.key in limit) or
+                # fallback for old event based entries
+                # if the base is an event, then using only attribute is fine
+                (c.base == "event" and c.attribute in limit)
+            ]
+
         if not kwargs.get('required', True):
             status_choices.insert(0, ('unset', _('Not set')))
+
+        choices = _get_choices(possible_choices)
+
         fields = reldatetimeparts(
             status=forms.ChoiceField(
                 choices=status_choices,
-                required=True
+                required=True,
             ),
             absolute=forms.DateTimeField(
                 required=False
@@ -329,7 +507,7 @@ class RelativeDateTimeField(forms.MultiValueField):
             ),
             rel_mins_relationto=forms.ChoiceField(
                 choices=choices,
-                required=False
+                required=False,
             ),
             rel_days_timeofday=forms.TimeField(
                 required=False,
@@ -339,7 +517,7 @@ class RelativeDateTimeField(forms.MultiValueField):
             ),
             rel_days_relationto=forms.ChoiceField(
                 choices=choices,
-                required=False
+                required=False,
             ),
             rel_mins_relation=forms.ChoiceField(
                 choices=BEFORE_AFTER_CHOICE,
@@ -350,8 +528,9 @@ class RelativeDateTimeField(forms.MultiValueField):
                 required=False
             ),
         )
+
         if 'widget' not in kwargs:
-            kwargs['widget'] = RelativeDateTimeWidget(status_choices=status_choices, base_choices=choices)
+            kwargs['widget'] = RelativeDateTimeWidget(status_choices=status_choices, base_choices=possible_choices)
         kwargs.pop('max_length', 0)
         kwargs.pop('empty_value', 0)
         super().__init__(
@@ -359,21 +538,24 @@ class RelativeDateTimeField(forms.MultiValueField):
         )
 
     def set_event(self, event):
-        self.widget.widgets[reldatetimeparts.indizes.rel_days_relationto].choices = [
-            (k, v) for k, v in BASE_CHOICES if getattr(event, k, None)
-        ]
-        self.widget.widgets[reldatetimeparts.indizes.rel_mins_relationto].choices = [
-            (k, v) for k, v in BASE_CHOICES if getattr(event, k, None)
-        ]
+        possible_choices = copy.deepcopy(EVENT_BASE_CHOICES)
+        if self.relative_to_order:
+            possible_choices.extend(ORDER_BASE_CHOICES)
+
+        possible_choices = possible_choices
+        choices = _get_choices(possible_choices)
+
+        self.widget.widgets[reldatetimeparts.indizes.rel_days_relationto].choices = choices
+        self.widget.widgets[reldatetimeparts.indizes.rel_mins_relationto].choices = choices
 
     def compress(self, data_list):
         if not data_list:
             return None
         data = reldatetimeparts(*data_list)
-        if data.status == 'absolute':
-            return RelativeDateWrapper(data.absolute)
-        elif data.status == 'unset':
+        if data.status == 'unset':
             return None
+        elif data.status == 'absolute':
+            return RelativeDateWrapper(data.absolute)
         elif data.status == 'relative_minutes':
             return RelativeDateWrapper(RelativeDate(
                 days=0,
@@ -404,6 +586,18 @@ class RelativeDateTimeField(forms.MultiValueField):
             raise ValidationError(self.error_messages['incomplete'])
         elif data.status == 'relative_minutes' and (data.rel_mins_number is None or not data.rel_mins_relationto):
             raise ValidationError(self.error_messages['incomplete'])
+        elif data.status == 'relative':
+            choice = BaseChoice.find(BASE_CHOICES, data.rel_days_relationto)
+            if data.rel_days_relation == "before" and not choice.supports_before:
+                raise ValidationError(_('A relative date cannot be expressed as "before" for "{}"'.format(choice.text)))
+            elif data.status == 'relative' and data.rel_days_relation == "after" and not choice.supports_after:
+                raise ValidationError(_('A relative date cannot be expressed as "after" for "{}"'.format(choice.text)))
+        elif data.status == 'relative_minutes':
+            choice = BaseChoice.find(BASE_CHOICES, data.rel_days_relationto)
+            if data.rel_days_relation == "before" and not choice.supports_before:
+                raise ValidationError(_('A relative time cannot be expressed as "before" for "{}"'.format(choice.text)))
+            elif data.rel_days_relation == "after" and not choice.supports_after:
+                raise ValidationError(_('A relative time cannot be expressed as "after" for "{}"'.format(choice.text)))
 
         return super().clean(value)
 
@@ -424,15 +618,20 @@ class RelativeDateWidget(RelativeDateTimeWidget):
 
     def __init__(self, *args, **kwargs):
         self.status_choices = kwargs.pop('status_choices')
-        widgets = reldateparts(
+        self.base_choices = kwargs.pop('base_choices')
+        widgets = cast(dict[str, Widget | type[Widget]], cast(object, reldateparts(
             status=forms.RadioSelect(choices=self.status_choices),
             absolute=forms.DateInput(
                 attrs={'class': 'datepickerfield'}
             ),
             rel_days_number=forms.NumberInput(),
-            rel_days_relationto=forms.Select(choices=kwargs.pop('base_choices')),
-            rel_days_relation=forms.Select(choices=BEFORE_AFTER_CHOICE),
-        )
+            rel_days_relationto=OptionAttrsSelect(
+                choices=self.base_choices,
+                option_attrs=_get_choice_validation_obj(self.base_choices),
+                attrs={'data-relative-choice': True},
+            ),
+            rel_days_relation=forms.Select(choices=BEFORE_AFTER_CHOICE, attrs={'data-relation-choice': True},),
+        )))
         forms.MultiWidget.__init__(self, widgets=widgets, *args, **kwargs)
 
     def decompress(self, value):
@@ -460,7 +659,7 @@ class RelativeDateWidget(RelativeDateTimeWidget):
             status="relative",
             absolute=None,
             rel_days_number=value.data.days,
-            rel_days_relationto=value.data.base_date_name,
+            rel_days_relationto=value.data.key,
             rel_days_relation="after" if value.data.is_after else "before"
         )
 
@@ -474,6 +673,15 @@ class RelativeDateField(RelativeDateTimeField):
         ]
         if not kwargs.get('required', True):
             status_choices.insert(0, ('unset', _('Not set')))
+
+        self.relative_to_order = kwargs.pop('relative_to_order', False)
+
+        possible_choices = copy.deepcopy(EVENT_BASE_CHOICES)
+        if self.relative_to_order:
+            possible_choices.extend(ORDER_BASE_CHOICES)
+
+        choices = _get_choices(possible_choices)
+
         fields = reldateparts(
             status=forms.ChoiceField(
                 choices=status_choices,
@@ -486,33 +694,37 @@ class RelativeDateField(RelativeDateTimeField):
                 required=False
             ),
             rel_days_relationto=forms.ChoiceField(
-                choices=BASE_CHOICES,
-                required=False
+                choices=choices,
+                required=False,
             ),
             rel_days_relation=forms.ChoiceField(
                 choices=BEFORE_AFTER_CHOICE,
                 required=False
             ),
         )
+
         if 'widget' not in kwargs:
-            kwargs['widget'] = RelativeDateWidget(status_choices=status_choices, base_choices=BASE_CHOICES)
+            kwargs['widget'] = RelativeDateWidget(status_choices=status_choices, base_choices=possible_choices)
         forms.MultiValueField.__init__(
             self, fields=fields, require_all_fields=False, *args, **kwargs
         )
 
     def set_event(self, event):
-        self.widget.widgets[reldateparts.indizes.rel_days_relationto].choices = [
-            (k, v) for k, v in BASE_CHOICES if getattr(event, k, None)
+        choices = [
+            (c.key, c.text) for c in EVENT_BASE_CHOICES if getattr(event, c.attribute, None)
         ]
+        if self.relative_to_order:
+            choices += [(c.key, c.text) for c in ORDER_BASE_CHOICES]
+        self.widget.widgets[reldateparts.indizes.rel_days_relationto].choices = choices
 
     def compress(self, data_list):
         if not data_list:
             return None
         data = reldateparts(*data_list)
-        if data.status == 'absolute':
-            return RelativeDateWrapper(data.absolute)
-        elif data.status == 'unset':
+        if data.status == 'unset':
             return None
+        elif data.status == 'absolute':
+            return RelativeDateWrapper(data.absolute)
         else:
             return RelativeDateWrapper(RelativeDate(
                 days=data.rel_days_number,
@@ -525,8 +737,14 @@ class RelativeDateField(RelativeDateTimeField):
         data = reldateparts(*value)
         if data.status == 'absolute' and not data.absolute:
             raise ValidationError(self.error_messages['incomplete'])
-        elif data.status == 'relative' and (data.rel_days_number is None or not data.rel_days_relationto):
-            raise ValidationError(self.error_messages['incomplete'])
+        if data.status == 'relative':
+            choice = BaseChoice.find(BASE_CHOICES, data.rel_days_relationto)
+            if data.rel_days_number is None or not data.rel_days_relationto:
+                raise ValidationError(self.error_messages['incomplete'])
+            elif data.rel_days_relation == "before" and not choice.supports_before:
+                raise ValidationError(_("A relative date cannot be expressed as 'before' for '{}'".format(choice.text)))
+            elif data.rel_days_relation == "after" and not choice.supports_after:
+                raise ValidationError(_("A relative date cannot be expressed as 'after' for '{}'".format(choice.text)))
 
         return forms.MultiValueField.clean(self, value)
 

src/pretix/base/services/checkin.py

@@ -40,7 +40,7 @@ import dateutil
 import dateutil.parser
 from dateutil.tz import datetime_exists
 from django.core.files import File
-from django.db import IntegrityError, transaction
+from django.db import IntegrityError
 from django.db.models import (
     BooleanField, Case, Count, ExpressionWrapper, F, IntegerField, Max, Min,
     OuterRef, Q, Subquery, TextField, Value, When,
@@ -59,6 +59,7 @@ from pretix.base.models import (
 )
 from pretix.base.signals import checkin_created, periodic_task
 from pretix.helpers import OF_SELF
+from pretix.helpers.database import conditional_atomic
 from pretix.helpers.jsonlogic import Logic
 from pretix.helpers.jsonlogic_boolalg import convert_to_dnf
 from pretix.helpers.jsonlogic_query import (
@@ -1043,10 +1044,10 @@ def perform_checkin(op: OrderPosition, clist: CheckinList, given_answers: dict,
         if not simulate:
             _save_answers(op, answers, given_answers)
 
-    with transaction.atomic():
+    with conditional_atomic(not simulate):
         # Lock order positions, if it is an entry. We don't need it for exits, as a race condition wouldn't be problematic
         opqs = OrderPosition.all.select_related("order", "item")
-        if type != Checkin.TYPE_EXIT:
+        if type != Checkin.TYPE_EXIT and not simulate:
             opqs = opqs.select_for_update(of=OF_SELF)
         op = opqs.get(pk=op.pk)
 

src/pretix/base/services/mail.py

@@ -32,6 +32,7 @@
 # Unless required by applicable law or agreed to in writing, software distributed under the Apache License 2.0 is
 # 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 hashlib
 import inspect
 import logging
@@ -42,6 +43,9 @@ import smtplib
 import uuid
 import warnings
 from datetime import timedelta
+from email import encoders, message_from_bytes
+from email.message import Message
+from email.mime.base import MIMEBase
 from email.mime.image import MIMEImage
 from email.utils import formataddr
 from typing import Any, Dict, List, Optional, Sequence, Union
@@ -53,12 +57,15 @@ from celery import chain
 from celery.exceptions import MaxRetriesExceededError
 from django.conf import settings
 from django.core.files.storage import default_storage
-from django.core.mail import EmailMultiAlternatives, SafeMIMEMultipart
-from django.core.mail.message import SafeMIMEText
+from django.core.mail import (
+    EmailMessage, EmailMultiAlternatives, SafeMIMEMultipart,
+)
+from django.core.mail.message import SafeMIMEMessage, SafeMIMEText
 from django.db import connection, transaction
 from django.db.models import Q
 from django.dispatch import receiver
 from django.template.loader import get_template
+from django.utils.encoding import force_bytes
 from django.utils.html import escape
 from django.utils.timezone import now, override
 from django.utils.translation import gettext as _, pgettext
@@ -382,15 +389,25 @@ def mail(email: Union[str, Sequence[str]], subject: Union[str, FormattedString],
 class CustomEmail(EmailMultiAlternatives):
     def _create_mime_attachment(self, content, mimetype):
         """
-        Convert the content, mimetype pair into a MIME attachment object.
-
-        If the mimetype is message/rfc822, content may be an
-        email.Message or EmailMessage object, as well as a str.
+        Modified version of EmailMessage._create_mime_attachment that supports multiparts and
+        never generates plaintext attachments.
         """
         basetype, subtype = mimetype.split('/', 1)
         if basetype == 'multipart' and isinstance(content, SafeMIMEMultipart):
-            return content
-        return super()._create_mime_attachment(content, mimetype)
+            attachment = content
+        # START: VENDORED FROM EmailMessage #
+        elif basetype == "message" and subtype == "rfc822":
+            if isinstance(content, EmailMessage):
+                content = content.message()
+            elif not isinstance(content, Message):
+                content = message_from_bytes(force_bytes(content))
+            attachment = SafeMIMEMessage(content, subtype)
+        else:
+            attachment = MIMEBase(basetype, subtype)
+            attachment.set_payload(content)
+            encoders.encode_base64(attachment)
+        return attachment
+        # END: VENDORED FROM EmailMessage #
 
 
 @app.task(base=TransactionAwareTask, bind=True, acks_late=True)

src/pretix/base/services/orders.py

@@ -48,12 +48,12 @@ from celery.exceptions import MaxRetriesExceededError
 from django.conf import settings
 from django.core.cache import cache
 from django.core.exceptions import ValidationError
-from django.db import transaction
+from django.db import models, transaction
 from django.db.models import (
-    Count, Exists, F, IntegerField, Max, Min, OuterRef, Q, QuerySet, Sum,
-    Value,
+    Count, Exists, F, IntegerField, Max, Min, OuterRef, Q, QuerySet, Subquery,
+    Sum, Value,
 )
-from django.db.models.functions import Coalesce, Greatest
+from django.db.models.functions import Cast, Greatest
 from django.db.transaction import get_connection
 from django.dispatch import receiver
 from django.utils.functional import cached_property
@@ -71,7 +71,7 @@ from pretix.base.models import (
     Membership, Order, OrderPayment, OrderPosition, Quota, Seat,
     SeatCategoryMapping, User, Voucher,
 )
-from pretix.base.models.event import SubEvent
+from pretix.base.models.event import Event_SettingsStore, SubEvent
 from pretix.base.models.orders import (
     BlockedTicketSecret, InvoiceAddress, OrderFee, OrderRefund,
     generate_secret,
@@ -1494,83 +1494,104 @@ def send_expiry_warnings(sender, **kwargs):
 @scopes_disabled()
 def send_download_reminders(sender, **kwargs):
     today = now().replace(hour=0, minute=0, second=0, microsecond=0)
-    qs = Order.objects.annotate(
-        first_date=Coalesce(
-            Min('all_positions__subevent__date_from'),
-            F('event__date_from')
+
+    events = Event.objects.filter(
+        Q(has_subevents=False, date_from__gte=now()) |
+        (Q(has_subevents=True) & Q(Exists(
+            SubEvent.objects.filter(event_id=OuterRef('id'), date_from__gte=now())
+        )))
+    ).annotate(
+        reminder_days=Subquery(
+            Event_SettingsStore.objects.filter(
+                object=OuterRef('id'),
+                key='mail_days_download_reminder'
+            ).exclude(
+                value="None"
+            ).annotate(
+                val=Cast(F("value"), output_field=models.IntegerField()),
+            ).values("val")
         )
     ).filter(
-        download_reminder_sent=False,
-        datetime__lte=now() - timedelta(hours=2),
-        first_date__gte=today,
-    ).only(
-        'pk', 'event_id', 'sales_channel', 'datetime',
-    ).order_by('event_id')
-    event_id = None
-    days = None
-    event = None
+        reminder_days__isnull=False,
+    ).order_by()
 
-    for o in qs:
-        if o.event_id != event_id:
-            days = o.event.settings.get('mail_days_download_reminder', as_type=int)
-            event = o.event
-            event_id = o.event_id
+    for event in events.iterator(chunk_size=10_000):
+        qs = event.orders.filter(
+            download_reminder_sent=False,
+            datetime__lte=now() - timedelta(hours=2),
+        )
 
-        if days is None:
-            continue
-
-        if o.sales_channel.identifier not in event.settings.mail_sales_channel_download_reminder:
-            continue
-
-        reminder_date = (o.first_date - timedelta(days=days)).replace(hour=0, minute=0, second=0, microsecond=0)
-        if now() < reminder_date or o.datetime > reminder_date:
-            continue
-
-        with transaction.atomic():
-            o = Order.objects.select_for_update(of=OF_SELF).get(pk=o.pk)
-            if o.download_reminder_sent:
-                # Race condition
-                continue
-            positions = list(o.positions_with_tickets)
-            if not positions:
+        if event.has_subevents:
+            qs = qs.annotate(
+                first_date=Min('all_positions__subevent__date_from')
+            ).filter(
+                Q(first_date__gte=today)
+            )
+        else:
+            event_reminder_date = (event.date_from - timedelta(days=event.reminder_days)).replace(hour=0, minute=0, second=0, microsecond=0)
+            if now() < event_reminder_date:
                 continue
 
-            if not o.ticket_download_available:
+        qs = qs.only(
+            'pk', 'event_id', 'sales_channel', 'datetime',
+        ).order_by()
+
+        for o in qs:
+            if o.sales_channel.identifier not in event.settings.mail_sales_channel_download_reminder:
                 continue
 
-            if o.status != Order.STATUS_PAID:
-                if o.status != Order.STATUS_PENDING or o.require_approval or (not o.valid_if_pending and not o.event.settings.ticket_download_pending):
+            if event.has_subevents:
+                reminder_date = ((o.first_date or event.date_from) - timedelta(days=event.reminder_days)).replace(hour=0, minute=0, second=0, microsecond=0)
+            else:
+                reminder_date = event_reminder_date
+            if now() < reminder_date or o.datetime > reminder_date:
+                continue
+
+            with transaction.atomic():
+                o = Order.objects.select_for_update(of=OF_SELF).get(pk=o.pk)
+                if o.download_reminder_sent:
+                    # Race condition
+                    continue
+                positions = list(o.positions_with_tickets)
+                if not positions:
                     continue
 
-            with language(o.locale, o.event.settings.region):
-                o.download_reminder_sent = True
-                o.save(update_fields=['download_reminder_sent'])
-                email_template = event.settings.mail_text_download_reminder
-                email_subject = event.settings.mail_subject_download_reminder
-                email_context = get_email_context(event=event, order=o)
-                o.send_mail(
-                    email_subject, email_template, email_context,
-                    'pretix.event.order.email.download_reminder_sent',
-                    attach_tickets=True
-                )
+                if not o.ticket_download_available:
+                    continue
 
-                if event.settings.mail_send_download_reminder_attendee:
-                    for p in positions:
-                        if p.subevent_id:
-                            reminder_date = (p.subevent.date_from - timedelta(days=days)).replace(
-                                hour=0, minute=0, second=0, microsecond=0
-                            )
-                            if now() < reminder_date:
-                                continue
-                        if p.addon_to_id is None and p.attendee_email and p.attendee_email != o.email:
-                            email_template = event.settings.mail_text_download_reminder_attendee
-                            email_subject = event.settings.mail_subject_download_reminder_attendee
-                            email_context = get_email_context(event=event, order=o, position=p)
-                            o.send_mail(
-                                email_subject, email_template, email_context,
-                                'pretix.event.order.email.download_reminder_sent',
-                                attach_tickets=True, position=p
-                            )
+                if o.status != Order.STATUS_PAID:
+                    if o.status != Order.STATUS_PENDING or o.require_approval or (not o.valid_if_pending and not o.event.settings.ticket_download_pending):
+                        continue
+
+                with language(o.locale, o.event.settings.region):
+                    o.download_reminder_sent = True
+                    o.save(update_fields=['download_reminder_sent'])
+                    email_template = event.settings.mail_text_download_reminder
+                    email_subject = event.settings.mail_subject_download_reminder
+                    email_context = get_email_context(event=event, order=o)
+                    o.send_mail(
+                        email_subject, email_template, email_context,
+                        'pretix.event.order.email.download_reminder_sent',
+                        attach_tickets=True
+                    )
+
+                    if event.settings.mail_send_download_reminder_attendee:
+                        for p in positions:
+                            if p.subevent_id:
+                                reminder_date = (p.subevent.date_from - timedelta(days=event.reminder_days)).replace(
+                                    hour=0, minute=0, second=0, microsecond=0
+                                )
+                                if now() < reminder_date:
+                                    continue
+                            if p.addon_to_id is None and p.attendee_email and p.attendee_email != o.email:
+                                email_template = event.settings.mail_text_download_reminder_attendee
+                                email_subject = event.settings.mail_subject_download_reminder_attendee
+                                email_context = get_email_context(event=event, order=o, position=p)
+                                o.send_mail(
+                                    email_subject, email_template, email_context,
+                                    'pretix.event.order.email.download_reminder_sent',
+                                    attach_tickets=True, position=p
+                                )
 
 
 def notify_user_changed_order(order, user=None, auth=None, invoices=[]):

src/pretix/base/settings.py

@@ -2930,7 +2930,7 @@ Your {event} team"""))  # noqa: W291
     },
     'mail_days_download_reminder': {
         'type': int,
-        'default': None
+        'default': None  # when this default is changed, send_download_reminders needs to change
     },
     'mail_send_download_reminder_attendee': {
         'type': bool,

src/pretix/control/forms/subevents.py

@@ -94,14 +94,14 @@ class SubEventBulkForm(SubEventForm):
         label=_('Start of presale'),
         help_text=_('Optional. No products will be sold before this date.'),
         required=False,
-        limit_choices=('date_from', 'date_to'),
+        limit_choices=('event__date_from', 'event__date_to'),
     )
     rel_presale_end = RelativeDateTimeField(
         label=_('End of presale'),
         help_text=_('Optional. No products will be sold after this date. If you do not set this value, the presale '
                     'will end after the end date of your event.'),
         required=False,
-        limit_choices=('date_from', 'date_to'),
+        limit_choices=('event__date_from', 'event__date_to'),
     )
     skip_if_overlap = forms.BooleanField(
         label=pgettext_lazy('subevent', 'Skip dates that overlap with any existing date'),
@@ -333,12 +333,12 @@ class BulkSubEventItemForm(SubEventItemForm):
     rel_available_from = RelativeDateTimeField(
         label=_('Available from'),
         required=False,
-        limit_choices=('date_from', 'date_to'),
+        limit_choices=('event__date_from', 'event__date_to'),
     )
     rel_available_until = RelativeDateTimeField(
         label=_('Available until'),
         required=False,
-        limit_choices=('date_from', 'date_to'),
+        limit_choices=('event__date_from', 'event__date_to'),
     )
 
     def __init__(self, *args, **kwargs):
@@ -355,12 +355,12 @@ class BulkSubEventItemVariationForm(SubEventItemVariationForm):
     rel_available_from = RelativeDateTimeField(
         label=_('Available from'),
         required=False,
-        limit_choices=('date_from', 'date_to'),
+        limit_choices=('event__date_from', 'event__date_to'),
     )
     rel_available_until = RelativeDateTimeField(
         label=_('Available_until'),
         required=False,
-        limit_choices=('date_from', 'date_to'),
+        limit_choices=('event__date_from', 'event__date_to'),
     )
 
     def __init__(self, *args, **kwargs):

src/pretix/control/templates/pretixcontrol/base.html

@@ -58,6 +58,7 @@
             <script type="text/javascript" src="{% static "leaflet/leaflet.js" %}"></script>
             <script type="text/javascript" src="{% static "pretixcontrol/js/ui/geo.js" %}"></script>
             <script type="text/javascript" src="{% static "pretixbase/js/details.js" %}"></script>
+            <script type="text/javascript" src="{% static "pretixbase/js/reldate.js" %}"></script>
             <script type="text/javascript" src="{% static "pretixbase/js/asynctask.js" %}"></script>
             <script type="text/javascript" src="{% static "sortable/Sortable.js" %}"></script>
             <script type="text/javascript" src="{% static "colorpicker/bootstrap-colorpicker.js" %}"></script>

src/pretix/control/views/subevents.py

@@ -431,7 +431,7 @@ class SubEventEditorMixin(MetaDataEditorMixin):
         days = (self.copy_from.date_from.astimezone(tz).date() - value.astimezone(tz).date()).days
         return RelativeDateWrapper(RelativeDate(
             days=abs(days),
-            base_date_name='date_from',
+            base_date_name='event__date_from',
             time=value.astimezone(tz).time(),
             minutes=None,
             is_after=days < 0,

src/pretix/helpers/database.py

@@ -288,6 +288,15 @@ def get_deterministic_ordering(model, ordering):
     return ordering
 
 
+@contextlib.contextmanager
+def conditional_atomic(do_atomic, **kwargs):
+    if do_atomic:
+        with transaction.atomic(**kwargs):
+            yield
+    else:
+        yield
+
+
 class IgnoreOnSQLiteMixin:
     # Mixin to allow defining PostgreSQL-specific indexes that will just not be created
     # on SQLite. SQLite is supported for testing only anyways!

src/pretix/static/pretixbase/js/reldate.js

@@ -0,0 +1,42 @@
+$(document).on('pretix:bind-forms', () => {
+	document.querySelectorAll('.reldatetime, .reldate').forEach(container => {
+		const groups = container.querySelectorAll('.radio')
+
+		groups.forEach(group => {
+			const referenceSelect = group.querySelector('select[data-relative-choice]')
+			const beforeAfterSelect = group.querySelector('select[data-relation-choice]')
+			if (!referenceSelect || !beforeAfterSelect) return
+
+			const beforeOption = beforeAfterSelect.querySelector('option[value="before"]')
+			const afterOption = beforeAfterSelect.querySelector('option[value="after"]')
+
+			const updateBeforeOption = () => {
+				let supportsBefore = referenceSelect.selectedOptions[0].hasAttribute('data-supports-before')
+				if (beforeOption) {
+					beforeOption.disabled = !beforeOption.disabled && !supportsBefore
+				}
+
+				let supportsAfter = referenceSelect.selectedOptions[0].hasAttribute('data-supports-after')
+				if (afterOption) {
+					afterOption.disabled = !afterOption.disabled && !supportsAfter
+				}
+
+				let dirty = false
+				if (beforeOption.disabled && beforeAfterSelect.value === 'before') {
+					beforeAfterSelect.value = 'after'
+					dirty = true
+				}
+				if (afterOption.disabled && beforeAfterSelect.value === 'after') {
+					beforeAfterSelect.value = 'before'
+					dirty = true
+				}
+
+				if (dirty) {
+					beforeAfterSelect.dispatchEvent(new Event('change', {bubbles: true}))
+				}
+			}
+			referenceSelect.addEventListener('change', updateBeforeOption)
+			updateBeforeOption()
+		})
+	})
+})

src/pretix/testutils/db.py

@@ -0,0 +1,25 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020  Raphael Michel and contributors
+# Copyright (C) 2020-today pretix 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/>.
+#
+def readonly_db(execute, sql, params, many, context):
+    if not sql.lower().startswith("select"):
+        raise Exception(f"Should not write anything to the database, but detected query: {sql}")
+    return execute(sql, params, many, context)

src/tests/api/test_checkinrpc.py

@@ -25,6 +25,7 @@ from unittest import mock
 
 import pytest
 from django.core.files.base import ContentFile
+from django.db import connection
 from django.utils.timezone import now
 from django_countries.fields import Country
 from django_scopes import scopes_disabled
@@ -36,6 +37,7 @@ from pretix.api.serializers.item import QuestionSerializer
 from pretix.base.models import (
     Checkin, InvoiceAddress, Item, Order, OrderPosition, ReusableMedium,
 )
+from pretix.testutils.db import readonly_db
 
 # Lots of this code is overlapping with test_checkin.py, and some of it is arguably redundant since it's triggering
 # the same backend code paths (for now). However, this is SUCH a critical part of pretix that we don't want to take
@@ -1739,3 +1741,41 @@ def test_exchange_create_gift_card(token_client, organizer, clist, event, order,
     with scopes_disabled():
         rm = ReusableMedium.objects.get(identifier="0412345")
         assert rm.linked_giftcard.currency == "EUR"
+
+
+@pytest.mark.django_db
+def test_simulate(token_client, organizer, clist, event, order):
+    with scopes_disabled():
+        p = order.positions.first()
+    with connection.execute_wrapper(readonly_db):
+        resp = _redeem(token_client, organizer, clist, p.secret, {"simulate": True})
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+    with scopes_disabled():
+        assert not p.checkins.exists()
+
+
+@pytest.mark.django_db
+def test_simulate_no_exchange(token_client, organizer, clist, event, order, item):
+    organizer.settings.reusable_media_type_nfc_uid = True
+    item.media_type = "nfc_uid"
+    item.media_policy = Item.MEDIA_POLICY_NEW
+    item.save()
+    with scopes_disabled():
+        rm = ReusableMedium.objects.create(
+            type="nfc_uid",
+            identifier="12345678",
+            organizer=organizer,
+        )
+    with connection.execute_wrapper(readonly_db):
+        resp = _redeem(token_client, organizer, clist, "z3fsn8jyufm5kpk768q69gkbyr5f4h6w", {
+            "source_type": "barcode",
+            "exchange_medium_type": "nfc_uid",
+            "exchange_medium_identifier": "12345678",
+            "simulate": True,
+        })
+    assert resp.status_code == 400
+    assert resp.data['status'] == 'error'
+    assert resp.data['reason'] == 'error'
+    with scopes_disabled():
+        assert not rm.linked_orderpositions.exists()

src/tests/base/test_models.py

@@ -473,7 +473,7 @@ class QuotaTestCase(BaseQuotaTestCase):
     @classscope(attr='o')
     def test_waitinglist_auto_disable(self):
         self.event.settings.waiting_list_auto_disable = RelativeDateWrapper(
-            RelativeDate(days=0, time=None, base_date_name='date_from', minutes=20, is_after=True)
+            RelativeDate(days=0, time=None, base_date_name='event__date_from', minutes=20, is_after=True)
         )
         self.quota.items.add(self.item1)
         self.quota.size = 1
@@ -484,7 +484,7 @@ class QuotaTestCase(BaseQuotaTestCase):
         self.assertEqual(self.item1.check_quotas(), (Quota.AVAILABILITY_ORDERED, 0))
         self.assertEqual(self.item1.check_quotas(count_waitinglist=False), (Quota.AVAILABILITY_OK, 1))
         self.event.settings.waiting_list_auto_disable = RelativeDateWrapper(
-            RelativeDate(days=0, time=None, base_date_name='date_from', minutes=20, is_after=False)
+            RelativeDate(days=0, time=None, base_date_name='event__date_from', minutes=20, is_after=False)
         )
         self.assertEqual(self.item1.check_quotas(), (Quota.AVAILABILITY_OK, 1))
         self.assertEqual(self.item1.check_quotas(count_waitinglist=False), (Quota.AVAILABILITY_OK, 1))
@@ -1192,7 +1192,7 @@ class OrderTestCase(BaseQuotaTestCase):
         self.op2.subevent = se2
         self.op2.save()
         self.event.settings.set('payment_term_last', RelativeDateWrapper(
-            RelativeDate(days=2, time=None, base_date_name='date_from', minutes=None)
+            RelativeDate(days=2, time=None, base_date_name='event__date_from', minutes=None)
         ))
 
         self.order.status = Order.STATUS_EXPIRED
@@ -1347,7 +1347,7 @@ class OrderTestCase(BaseQuotaTestCase):
         self.op2.subevent = se2
         self.op2.save()
         self.event.settings.set('last_order_modification_date', RelativeDateWrapper(
-            RelativeDate(days=2, time=None, base_date_name='date_from', minutes=None)
+            RelativeDate(days=2, time=None, base_date_name='event__date_from', minutes=None)
         ))
         assert self.order.can_modify_answers
         self.op2.subevent = se3
@@ -1363,7 +1363,7 @@ class OrderTestCase(BaseQuotaTestCase):
         self.event.date_from = datetime.datetime(2017, 5, 3, 12, 0, 0, tzinfo=datetime.timezone.utc)
         self.event.save()
         self.event.settings.set('payment_term_last', RelativeDateWrapper(
-            RelativeDate(days=2, time=None, base_date_name='date_from', minutes=None)
+            RelativeDate(days=2, time=None, base_date_name='event__date_from', minutes=None)
         ))
         assert self.order.payment_term_last == datetime.datetime(2017, 5, 1, 23, 59, 59, tzinfo=datetime.timezone.utc)
 
@@ -1379,7 +1379,7 @@ class OrderTestCase(BaseQuotaTestCase):
         self.op2.subevent = se2
         self.op2.save()
         self.event.settings.set('payment_term_last', RelativeDateWrapper(
-            RelativeDate(days=2, time=None, base_date_name='date_from', minutes=None)
+            RelativeDate(days=2, time=None, base_date_name='event__date_from', minutes=None)
         ))
         assert self.order.payment_term_last > now()
         self.op2.subevent = se3
@@ -1395,7 +1395,7 @@ class OrderTestCase(BaseQuotaTestCase):
         self.event.date_from = datetime.datetime(2017, 5, 3, 12, 0, 0, tzinfo=datetime.timezone.utc)
         self.event.save()
         self.event.settings.set('ticket_download_date', RelativeDateWrapper(
-            RelativeDate(days=2, time=None, base_date_name='date_from', minutes=None)
+            RelativeDate(days=2, time=None, base_date_name='event__date_from', minutes=None)
         ))
         assert self.order.ticket_download_date == datetime.datetime(2017, 5, 1, 12, 0, 0, tzinfo=datetime.timezone.utc)
 
@@ -1411,7 +1411,7 @@ class OrderTestCase(BaseQuotaTestCase):
         self.op2.subevent = se2
         self.op2.save()
         self.event.settings.set('ticket_download_date', RelativeDateWrapper(
-            RelativeDate(days=2, time=None, base_date_name='date_from', minutes=None)
+            RelativeDate(days=2, time=None, base_date_name='event__date_from', minutes=None)
         ))
         assert self.order.ticket_download_date > now()
         self.op2.subevent = se3
@@ -1582,13 +1582,13 @@ class OrderTestCase(BaseQuotaTestCase):
 
         assert self.order.user_cancel_deadline is None
         self.event.settings.set('cancel_allow_user_until', RelativeDateWrapper(
-            RelativeDate(days=2, time=datetime.time(14, 0, 0), base_date_name='date_from', minutes=None)
+            RelativeDate(days=2, time=datetime.time(14, 0, 0), base_date_name='event__date_from', minutes=None)
         ))
         self.order = Order.objects.get(pk=self.order.pk)
         assert self.order.user_cancel_deadline > now()
         assert self.order.user_cancel_allowed
         self.event.settings.set('cancel_allow_user_until', RelativeDateWrapper(
-            RelativeDate(days=4, time=datetime.time(14, 0, 0), base_date_name='date_from', minutes=None)
+            RelativeDate(days=4, time=datetime.time(14, 0, 0), base_date_name='event__date_from', minutes=None)
         ))
         self.order = Order.objects.get(pk=self.order.pk)
         assert self.order.user_cancel_deadline < now()
@@ -1607,7 +1607,7 @@ class OrderTestCase(BaseQuotaTestCase):
         self.op2.save()
 
         self.event.settings.set('cancel_allow_user_until', RelativeDateWrapper(
-            RelativeDate(days=2, time=datetime.time(14, 0, 0), base_date_name='date_from', minutes=None)
+            RelativeDate(days=2, time=datetime.time(14, 0, 0), base_date_name='event__date_from', minutes=None)
         ))
         self.order = Order.objects.get(pk=self.order.pk)
         assert self.order.user_cancel_deadline < now()
@@ -2018,13 +2018,13 @@ class OrderTestCase(BaseQuotaTestCase):
 
         assert self.order.user_change_deadline is None
         self.event.settings.set('change_allow_user_until', RelativeDateWrapper(
-            RelativeDate(days=2, time=datetime.time(14, 0, 0), base_date_name='date_from', minutes=None)
+            RelativeDate(days=2, time=datetime.time(14, 0, 0), base_date_name='event__date_from', minutes=None)
         ))
         self.order = Order.objects.get(pk=self.order.pk)
         assert self.order.user_change_deadline > now()
         assert self.order.user_change_allowed
         self.event.settings.set('change_allow_user_until', RelativeDateWrapper(
-            RelativeDate(days=4, time=datetime.time(14, 0, 0), base_date_name='date_from', minutes=None)
+            RelativeDate(days=4, time=datetime.time(14, 0, 0), base_date_name='event__date_from', minutes=None)
         ))
         self.order = Order.objects.get(pk=self.order.pk)
         assert self.order.user_change_deadline < now()
@@ -2046,7 +2046,7 @@ class OrderTestCase(BaseQuotaTestCase):
         self.op2.save()
 
         self.event.settings.set('change_allow_user_until', RelativeDateWrapper(
-            RelativeDate(days=2, time=datetime.time(14, 0, 0), base_date_name='date_from', minutes=None)
+            RelativeDate(days=2, time=datetime.time(14, 0, 0), base_date_name='event__date_from', minutes=None)
         ))
         self.order = Order.objects.get(pk=self.order.pk)
         assert self.order.user_change_deadline < now()

src/tests/base/test_orders.py

@@ -204,7 +204,7 @@ def test_expiry_last_relative(event):
     event.date_from = now() + timedelta(days=5)
     event.save()
     event.settings.set('payment_term_last', RelativeDateWrapper(
-        RelativeDate(days=2, time=None, base_date_name='date_from', minutes=None)
+        RelativeDate(days=2, time=None, base_date_name='event__date_from', minutes=None)
     ))
     order = _create_order(event, email='dummy@example.org', positions=[],
                           now_dt=today,
@@ -245,7 +245,7 @@ def test_expiry_last_relative_subevents(event):
     )
 
     event.settings.set('payment_term_last', RelativeDateWrapper(
-        RelativeDate(days=2, time=None, base_date_name='date_from', minutes=None)
+        RelativeDate(days=2, time=None, base_date_name='event__date_from', minutes=None)
     ))
     order = _create_order(event, email='dummy@example.org', positions=[cp1, cp2],
                           now_dt=today,

src/tests/base/test_payment.py

@@ -133,7 +133,7 @@ def test_availability_date_relative(event):
     event.save()
     prov = DummyPaymentProvider(event)
     prov.settings.set('_availability_date', RelativeDateWrapper(
-        RelativeDate(days=2, time=None, base_date_name='date_from', minutes=None)
+        RelativeDate(days=2, time=None, base_date_name='event__date_from', minutes=None)
     ))
 
     utc = datetime.timezone.utc
@@ -150,7 +150,7 @@ def test_availability_start_relative(event):
     event.save()
     prov = DummyPaymentProvider(event)
     prov.settings.set('_availability_start', RelativeDateWrapper(
-        RelativeDate(days=2, time=datetime.time(12, 0), base_date_name='date_from', minutes=None)
+        RelativeDate(days=2, time=datetime.time(12, 0), base_date_name='event__date_from', minutes=None)
     ))
 
     utc = datetime.timezone.utc
@@ -193,12 +193,12 @@ def test_availability_date_cart_relative_subevents(event):
 
     prov = DummyPaymentProvider(event)
     prov.settings.set('_availability_date', RelativeDateWrapper(
-        RelativeDate(days=3, time=None, base_date_name='date_from', minutes=None)
+        RelativeDate(days=3, time=None, base_date_name='event__date_from', minutes=None)
     ))
     assert prov._is_available_by_time(cart_id="123")
 
     prov.settings.set('_availability_date', RelativeDateWrapper(
-        RelativeDate(days=4, time=None, base_date_name='date_from', minutes=None)
+        RelativeDate(days=4, time=None, base_date_name='event__date_from', minutes=None)
     ))
     assert not prov._is_available_by_time(cart_id="123")
 
@@ -233,11 +233,11 @@ def test_availability_date_order_relative_subevents(event):
 
     prov = DummyPaymentProvider(event)
     prov.settings.set('_availability_date', RelativeDateWrapper(
-        RelativeDate(days=3, time=None, base_date_name='date_from', minutes=None)
+        RelativeDate(days=3, time=None, base_date_name='event__date_from', minutes=None)
     ))
     assert prov._is_available_by_time(order=order)
 
     prov.settings.set('_availability_date', RelativeDateWrapper(
-        RelativeDate(days=4, time=None, base_date_name='date_from', minutes=None)
+        RelativeDate(days=4, time=None, base_date_name='event__date_from', minutes=None)
     ))
     assert not prov._is_available_by_time(order=order)

src/tests/base/test_reldate.py

@@ -19,13 +19,13 @@
 # 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 datetime import datetime, time
+from datetime import datetime, time, timedelta
 from zoneinfo import ZoneInfo
 
 import pytest
 from django_scopes import scope
 
-from pretix.base.models import Event, Organizer
+from pretix.base.models import Event, Order, Organizer
 from pretix.base.reldate import RelativeDate, RelativeDateWrapper
 
 TOKYO = ZoneInfo('Asia/Tokyo')
@@ -40,7 +40,6 @@ def event():
         date_from=datetime(2017, 12, 27, 5, 0, 0, tzinfo=TOKYO),
         presale_start=datetime(2017, 12, 1, 5, 0, 0, tzinfo=TOKYO),
         plugins='pretix.plugins.banktransfer'
-
     )
     event.settings.timezone = "Asia/Tokyo"
     return event
@@ -56,57 +55,57 @@ def test_absolute_date(event):
 
 @pytest.mark.django_db
 def test_relative_date_without_time(event):
-    rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='date_from', minutes=None))
+    rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='event__date_from', minutes=None))
     assert rdw.datetime(event).astimezone(TOKYO) == datetime(2017, 12, 26, 5, 0, 0, tzinfo=TOKYO)
-    assert rdw.to_string() == 'RELDATE/1/-/date_from/'
-    rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='date_from', minutes=None, is_after=True))
+    assert rdw.to_string() == 'RELDATE/1/-/event__date_from/'
+    rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='event__date_from', minutes=None, is_after=True))
     assert rdw.datetime(event).astimezone(TOKYO) == datetime(2017, 12, 28, 5, 0, 0, tzinfo=TOKYO)
-    assert rdw.to_string() == 'RELDATE/1/-/date_from/after'
+    assert rdw.to_string() == 'RELDATE/1/-/event__date_from/after'
 
 
 @pytest.mark.django_db
 def test_relative_date_other_base_point(event):
     with scope(organizer=event.organizer):
-        rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='presale_start', minutes=None))
+        rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='event__presale_start', minutes=None))
         assert rdw.datetime(event) == datetime(2017, 11, 30, 5, 0, 0, tzinfo=TOKYO)
-        assert rdw.to_string() == 'RELDATE/1/-/presale_start/'
+        assert rdw.to_string() == 'RELDATE/1/-/event__presale_start/'
 
         # presale_end is unset, defaults to date_from
-        rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='presale_end', minutes=None))
+        rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='event__presale_end', minutes=None))
         assert rdw.datetime(event) == datetime(2017, 12, 26, 5, 0, 0, tzinfo=TOKYO)
-        assert rdw.to_string() == 'RELDATE/1/-/presale_end/'
+        assert rdw.to_string() == 'RELDATE/1/-/event__presale_end/'
 
         # subevent base
         se = event.subevents.create(name="SE1", date_from=datetime(2017, 11, 27, 5, 0, 0, tzinfo=TOKYO))
-        rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='date_from', minutes=None))
+        rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='event__date_from', minutes=None))
         assert rdw.datetime(se) == datetime(2017, 11, 26, 5, 0, 0, tzinfo=TOKYO)
 
         # presale_start is unset on subevent, default to event
-        rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='presale_start', minutes=None))
+        rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='event__presale_start', minutes=None))
         assert rdw.datetime(se) == datetime(2017, 11, 30, 5, 0, 0, tzinfo=TOKYO)
 
         # presale_end is unset on all, default to date_from of subevent
-        rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='presale_end', minutes=None))
+        rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='event__presale_end', minutes=None))
         assert rdw.datetime(se) == datetime(2017, 11, 26, 5, 0, 0, tzinfo=TOKYO)
 
 
 @pytest.mark.django_db
 def test_relative_date_in_minutes(event):
-    rdw = RelativeDateWrapper(RelativeDate(days=0, time=None, base_date_name='date_from', minutes=60))
-    assert rdw.to_string() == 'RELDATE/minutes/60/date_from/'
+    rdw = RelativeDateWrapper(RelativeDate(days=0, time=None, base_date_name='event__date_from', minutes=60))
+    assert rdw.to_string() == 'RELDATE/minutes/60/event__date_from/'
     assert rdw.datetime(event) == datetime(2017, 12, 27, 4, 0, 0, tzinfo=TOKYO)
-    rdw = RelativeDateWrapper(RelativeDate(days=0, time=None, base_date_name='date_from', minutes=60, is_after=True))
-    assert rdw.to_string() == 'RELDATE/minutes/60/date_from/after'
+    rdw = RelativeDateWrapper(RelativeDate(days=0, time=None, base_date_name='event__date_from', minutes=60, is_after=True))
+    assert rdw.to_string() == 'RELDATE/minutes/60/event__date_from/after'
     assert rdw.datetime(event) == datetime(2017, 12, 27, 6, 0, 0, tzinfo=TOKYO)
 
 
 @pytest.mark.django_db
 def test_relative_date_with_time(event):
-    rdw = RelativeDateWrapper(RelativeDate(days=1, time=time(8, 5, 13), base_date_name='date_from', minutes=None))
-    assert rdw.to_string() == 'RELDATE/1/08:05:13/date_from/'
+    rdw = RelativeDateWrapper(RelativeDate(days=1, time=time(8, 5, 13), base_date_name='event__date_from', minutes=None))
+    assert rdw.to_string() == 'RELDATE/1/08:05:13/event__date_from/'
     assert rdw.datetime(event) == datetime(2017, 12, 26, 8, 5, 13, tzinfo=TOKYO)
-    rdw = RelativeDateWrapper(RelativeDate(days=1, time=time(8, 5, 13), base_date_name='date_from', minutes=None, is_after=True))
-    assert rdw.to_string() == 'RELDATE/1/08:05:13/date_from/after'
+    rdw = RelativeDateWrapper(RelativeDate(days=1, time=time(8, 5, 13), base_date_name='event__date_from', minutes=None, is_after=True))
+    assert rdw.to_string() == 'RELDATE/1/08:05:13/event__date_from/after'
     assert rdw.datetime(event) == datetime(2017, 12, 28, 8, 5, 13, tzinfo=TOKYO)
 
 
@@ -115,35 +114,94 @@ def test_relative_date_with_time_around_dst(event):
     event.settings.timezone = "Europe/Berlin"
     event.date_from = datetime(2020, 3, 29, 18, 0, 0, tzinfo=BERLIN)
 
-    rdw = RelativeDateWrapper(RelativeDate(days=1, time=time(18, 0, 0), base_date_name='date_from', minutes=None))
-    assert rdw.to_string() == 'RELDATE/1/18:00:00/date_from/'
+    rdw = RelativeDateWrapper(RelativeDate(days=1, time=time(18, 0, 0), base_date_name='event__date_from', minutes=None))
+    assert rdw.to_string() == 'RELDATE/1/18:00:00/event__date_from/'
     assert rdw.datetime(event) == datetime(2020, 3, 28, 18, 0, 0, tzinfo=BERLIN)
 
-    rdw = RelativeDateWrapper(RelativeDate(days=0, time=time(2, 30, 0), base_date_name='date_from', minutes=None))
-    assert rdw.to_string() == 'RELDATE/0/02:30:00/date_from/'
+    rdw = RelativeDateWrapper(RelativeDate(days=0, time=time(2, 30, 0), base_date_name='event__date_from', minutes=None))
+    assert rdw.to_string() == 'RELDATE/0/02:30:00/event__date_from/'
     assert rdw.datetime(event) == datetime(2020, 3, 29, 2, 30, 0, tzinfo=BERLIN)
 
     event.date_from = datetime(2020, 10, 25, 18, 0, 0, tzinfo=BERLIN)
 
-    rdw = RelativeDateWrapper(RelativeDate(days=1, time=time(18, 0, 0), base_date_name='date_from', minutes=None))
-    assert rdw.to_string() == 'RELDATE/1/18:00:00/date_from/'
+    rdw = RelativeDateWrapper(RelativeDate(days=1, time=time(18, 0, 0), base_date_name='event__date_from', minutes=None))
+    assert rdw.to_string() == 'RELDATE/1/18:00:00/event__date_from/'
     assert rdw.datetime(event) == datetime(2020, 10, 24, 18, 0, 0, tzinfo=BERLIN)
 
-    rdw = RelativeDateWrapper(RelativeDate(days=0, time=time(2, 30, 0), base_date_name='date_from', minutes=None))
-    assert rdw.to_string() == 'RELDATE/0/02:30:00/date_from/'
+    rdw = RelativeDateWrapper(RelativeDate(days=0, time=time(2, 30, 0), base_date_name='event__date_from', minutes=None))
+    assert rdw.to_string() == 'RELDATE/0/02:30:00/event__date_from/'
     assert rdw.datetime(event) == datetime(2020, 10, 25, 2, 30, 0, tzinfo=BERLIN)
 
 
-def test_unserialize():
+def test_unserialize_backwards_compatibility():
+    d = datetime(2017, 12, 25, 10, 0, 0, tzinfo=TOKYO)
+    rdw = RelativeDateWrapper.from_string(d.isoformat())
+    assert rdw.data == d
+
+    # keeping the test for the old from_string_format to ensure that we don't break anything
+    rdw = RelativeDateWrapper.from_string('RELDATE/1/-/date_from/')
+    assert rdw.data == RelativeDate(days=1, time=None, base_date_name='date_from', minutes=None)
+
+    # keeping the test for the old from_string_format to ensure that we don't break anything
+    rdw = RelativeDateWrapper.from_string('RELDATE/1/18:05:13/date_from/')
+    assert rdw.data == RelativeDate(days=1, time=time(18, 5, 13), base_date_name='date_from', minutes=None)
+
+    # keeping the test for the old from_string_format to ensure that we don't break anything
+    rdw = RelativeDateWrapper.from_string('RELDATE/minutes/60/date_from/')
+    assert rdw.data == RelativeDate(days=0, time=None, base_date_name='date_from', minutes=60)
+
+
+def test_backwards_compatibility():
+    # the data model of RelativeDate had to be extended to support other models as relation target
+    # previously only:
+    # - date_from
+    # - date_to
+    # - date_admission
+    # - presale_start
+    # - presale_end
+    # where valid values for the fourth slot (base_date_names) of the serialized form.
+    # the relationship in this case always pointed at event
+    # so any preexisting base_date_names without __ should continue to work and upgrade to event__{old_base_date_name}
     d = datetime(2017, 12, 25, 10, 0, 0, tzinfo=TOKYO)
     rdw = RelativeDateWrapper.from_string(d.isoformat())
     assert rdw.data == d
 
     rdw = RelativeDateWrapper.from_string('RELDATE/1/-/date_from/')
-    assert rdw.data == RelativeDate(days=1, time=None, base_date_name='date_from', minutes=None)
+    assert rdw.to_string() == 'RELDATE/1/-/event__date_from/'
 
-    rdw = RelativeDateWrapper.from_string('RELDATE/1/18:05:13/date_from/')
-    assert rdw.data == RelativeDate(days=1, time=time(18, 5, 13), base_date_name='date_from', minutes=None)
+    rdw = RelativeDateWrapper.from_string('RELDATE/1/-/date_to/')
+    assert rdw.to_string() == 'RELDATE/1/-/event__date_to/'
 
-    rdw = RelativeDateWrapper.from_string('RELDATE/minutes/60/date_from/')
-    assert rdw.data == RelativeDate(days=0, time=None, base_date_name='date_from', minutes=60)
+    rdw = RelativeDateWrapper.from_string('RELDATE/1/-/date_admission/')
+    assert rdw.to_string() == 'RELDATE/1/-/event__date_admission/'
+
+    rdw = RelativeDateWrapper.from_string('RELDATE/1/-/presale_start/')
+    assert rdw.to_string() == 'RELDATE/1/-/event__presale_start/'
+
+    rdw = RelativeDateWrapper.from_string('RELDATE/1/-/presale_end/')
+    assert rdw.to_string() == 'RELDATE/1/-/event__presale_end/'
+
+    # new order base_date_names should not work without __
+    with pytest.raises(TypeError):
+        RelativeDateWrapper.from_string('RELDATE/1/-/datetime/')
+    with pytest.raises(TypeError):
+        RelativeDateWrapper.from_string('RELDATE/1/-/expires/')
+
+
+@pytest.mark.django_db
+def test_relative_to_order(event):
+    with scope(organizer=event.organizer):
+        order_moment = datetime(2020, 3, 29, 18, 0, 0, tzinfo=TOKYO)
+
+        order = Order.objects.create(
+            code='FOO', event=event, email='dummy@dummy.test',
+            status=Order.STATUS_PENDING, secret="k24fiuwvu8kxz3y1",
+            datetime=order_moment,
+            expires=order_moment + timedelta(days=10),
+            sales_channel=event.organizer.sales_channels.get(identifier="web"),
+            total=23, locale='en'
+        )
+
+        rdw = RelativeDateWrapper(RelativeDate(days=1, time=None, base_date_name='order__datetime', minutes=None, is_after=True))
+        assert rdw.datetime(order).astimezone(TOKYO) == datetime(2020, 3, 30, 18, 0, 0, tzinfo=TOKYO)
+        assert rdw.to_string() == 'RELDATE/1/-/order__datetime/after'

src/tests/base/test_waitinglist.py

@@ -235,7 +235,7 @@ class WaitingListTestCase(TestCase):
         self.event.settings.set('waiting_list_enabled', True)
         self.event.settings.set('waiting_list_auto', True)
         self.event.settings.waiting_list_auto_disable = RelativeDateWrapper(
-            RelativeDate(days=0, time=None, base_date_name='date_from', minutes=20, is_after=False)
+            RelativeDate(days=0, time=None, base_date_name='event__date_from', minutes=20, is_after=False)
         )
         self.event.save()
         with scope(organizer=self.o):

src/tests/control/test_events.py

@@ -481,7 +481,7 @@ class EventsTest(SoupTest):
             'payment_term_last_0': 'absolute',
             'payment_term_last_1': (self.event1.presale_end - datetime.timedelta(1)).strftime('%Y-%m-%d'),
             'payment_term_last_2': '0',
-            'payment_term_last_3': 'date_from',
+            'payment_term_last_3': 'event__date_from',
             'tax_rule_payment': 'default',
         })
         assert doc.select('.alert-danger')
@@ -496,7 +496,7 @@ class EventsTest(SoupTest):
             'payment_term_last_0': 'relative',
             'payment_term_last_1': '',
             'payment_term_last_2': '10',
-            'payment_term_last_3': 'date_from',
+            'payment_term_last_3': 'event__date_from',
             'tax_rule_payment': 'default',
         })
         assert doc.select('.alert-danger')

src/tests/control/test_subevents.py

@@ -230,19 +230,19 @@ class SubEventsTest(SoupTest):
             'rel_presale_start_0': 'unset',
             'rel_presale_start_1': '',
             'rel_presale_start_2': '1',
-            'rel_presale_start_3': 'date_from',
+            'rel_presale_start_3': 'event__date_from',
             'rel_presale_start_4': '',
             'rel_presale_start_5': '',
-            'rel_presale_start_6': 'date_from',
+            'rel_presale_start_6': 'event__date_from',
             'rel_presale_start_7': 'before',
             'rel_presale_start_8': 'before',
             'rel_presale_end_1': '',
             'rel_presale_end_0': 'relative',
             'rel_presale_end_2': '1',
-            'rel_presale_end_3': 'date_from',
+            'rel_presale_end_3': 'event__date_from',
             'rel_presale_end_4': '13:29:31',
             'rel_presale_end_5': '',
-            'rel_presale_end_6': 'date_from',
+            'rel_presale_end_6': 'event__date_from',
             'rel_presale_end_7': 'before',
             'rel_presale_end_8': 'before',
             'quotas-TOTAL_FORMS': '1',
@@ -328,19 +328,19 @@ class SubEventsTest(SoupTest):
             'rel_presale_start_0': 'unset',
             'rel_presale_start_1': '',
             'rel_presale_start_2': '1',
-            'rel_presale_start_3': 'date_from',
+            'rel_presale_start_3': 'event__date_from',
             'rel_presale_start_4': '',
             'rel_presale_start_5': '',
-            'rel_presale_start_6': 'date_from',
+            'rel_presale_start_6': 'event__date_from',
             'rel_presale_start_7': 'before',
             'rel_presale_start_8': 'before',
             'rel_presale_end_1': '',
             'rel_presale_end_0': 'relative',
             'rel_presale_end_2': '1',
-            'rel_presale_end_3': 'date_from',
+            'rel_presale_end_3': 'event__date_from',
             'rel_presale_end_4': '13:29:31',
             'rel_presale_end_5': '',
-            'rel_presale_end_6': 'date_from',
+            'rel_presale_end_6': 'event__date_from',
             'rel_presale_end_7': 'before',
             'rel_presale_end_8': 'before',
             'quotas-TOTAL_FORMS': '1',
@@ -403,19 +403,19 @@ class SubEventsTest(SoupTest):
             'rel_presale_start_0': 'unset',
             'rel_presale_start_1': '',
             'rel_presale_start_2': '1',
-            'rel_presale_start_3': 'date_from',
+            'rel_presale_start_3': 'event__date_from',
             'rel_presale_start_4': '',
             'rel_presale_start_5': '',
-            'rel_presale_start_6': 'date_from',
+            'rel_presale_start_6': 'event__date_from',
             'rel_presale_start_7': 'before',
             'rel_presale_start_8': 'before',
             'rel_presale_end_1': '',
             'rel_presale_end_0': 'relative',
             'rel_presale_end_2': '1',
-            'rel_presale_end_3': 'date_from',
+            'rel_presale_end_3': 'event__date_from',
             'rel_presale_end_4': '13:29:31',
             'rel_presale_end_5': '',
-            'rel_presale_end_6': 'date_from',
+            'rel_presale_end_6': 'event__date_from',
             'rel_presale_end_7': 'before',
             'rel_presale_end_8': 'before',
             'quotas-TOTAL_FORMS': '1',
@@ -479,19 +479,19 @@ class SubEventsTest(SoupTest):
             'rel_presale_start_0': 'unset',
             'rel_presale_start_1': '',
             'rel_presale_start_2': '1',
-            'rel_presale_start_3': 'date_from',
+            'rel_presale_start_3': 'event__date_from',
             'rel_presale_start_4': '',
             'rel_presale_start_5': '',
-            'rel_presale_start_6': 'date_from',
+            'rel_presale_start_6': 'event__date_from',
             'rel_presale_start_7': 'before',
             'rel_presale_start_8': 'before',
             'rel_presale_end_1': '',
             'rel_presale_end_0': 'relative',
             'rel_presale_end_2': '1',
-            'rel_presale_end_3': 'date_from',
+            'rel_presale_end_3': 'event__date_from',
             'rel_presale_end_4': '02:30:00',
             'rel_presale_end_5': '',
-            'rel_presale_end_6': 'date_from',
+            'rel_presale_end_6': 'event__date_from',
             'rel_presale_end_7': 'before',
             'rel_presale_end_8': 'before',
             'quotas-TOTAL_FORMS': '1',
@@ -567,19 +567,19 @@ class SubEventsTest(SoupTest):
             'rel_presale_start_0': 'unset',
             'rel_presale_start_1': '',
             'rel_presale_start_2': '1',
-            'rel_presale_start_3': 'date_from',
+            'rel_presale_start_3': 'event__date_from',
             'rel_presale_start_4': '',
             'rel_presale_start_5': '',
-            'rel_presale_start_6': 'date_from',
+            'rel_presale_start_6': 'event__date_from',
             'rel_presale_start_7': 'before',
             'rel_presale_start_8': 'before',
             'rel_presale_end_1': '',
             'rel_presale_end_0': 'relative',
             'rel_presale_end_2': '1',
-            'rel_presale_end_3': 'date_from',
+            'rel_presale_end_3': 'event__date_from',
             'rel_presale_end_4': '13:29:31',
             'rel_presale_end_5': '',
-            'rel_presale_end_6': 'date_from',
+            'rel_presale_end_6': 'event__date_from',
             'rel_presale_end_7': 'before',
             'rel_presale_end_8': 'before',
             'quotas-TOTAL_FORMS': '1',
@@ -639,19 +639,19 @@ class SubEventsTest(SoupTest):
             'rel_presale_start_0': 'unset',
             'rel_presale_start_1': '',
             'rel_presale_start_2': '1',
-            'rel_presale_start_3': 'date_from',
+            'rel_presale_start_3': 'event__date_from',
             'rel_presale_start_4': '',
             'rel_presale_start_5': '',
-            'rel_presale_start_6': 'date_from',
+            'rel_presale_start_6': 'event__date_from',
             'rel_presale_start_7': 'before',
             'rel_presale_start_8': 'before',
             'rel_presale_end_0': 'unset',
             'rel_presale_end_1': '',
             'rel_presale_end_2': '1',
-            'rel_presale_end_3': 'date_from',
+            'rel_presale_end_3': 'event__date_from',
             'rel_presale_end_4': '13:29:31',
             'rel_presale_end_5': '',
-            'rel_presale_end_6': 'date_from',
+            'rel_presale_end_6': 'event__date_from',
             'rel_presale_end_7': 'before',
             'rel_presale_end_8': 'before',
             'quotas-TOTAL_FORMS': '1',
@@ -711,19 +711,19 @@ class SubEventsTest(SoupTest):
             'rel_presale_start_0': 'unset',
             'rel_presale_start_1': '',
             'rel_presale_start_2': '1',
-            'rel_presale_start_3': 'date_from',
+            'rel_presale_start_3': 'event__date_from',
             'rel_presale_start_4': '',
             'rel_presale_start_5': '',
-            'rel_presale_start_6': 'date_from',
+            'rel_presale_start_6': 'event__date_from',
             'rel_presale_start_7': 'before',
             'rel_presale_start_8': 'before',
             'rel_presale_end_0': 'unset',
             'rel_presale_end_1': '',
             'rel_presale_end_2': '1',
-            'rel_presale_end_3': 'date_from',
+            'rel_presale_end_3': 'event__date_from',
             'rel_presale_end_4': '13:29:31',
             'rel_presale_end_5': '',
-            'rel_presale_end_6': 'date_from',
+            'rel_presale_end_6': 'event__date_from',
             'rel_presale_end_7': 'before',
             'rel_presale_end_8': 'before',
             'quotas-TOTAL_FORMS': '1',

src/tests/control/test_views.py

@@ -224,3 +224,28 @@ def test_one_view(logged_in_client, url, expected, event, item, item_category, o
         )
     response = logged_in_client.get(url)
     assert response.status_code == expected
+
+    # Do not reintroduce any CSP nonces into control responses, as discussed in PR #6387
+    if response['Content-Type'] != 'application/json':
+        assert 'script-src' in response['Content-Security-Policy']
+        assert 'nonce-' not in response['Content-Security-Policy']
+
+
+@pytest.mark.parametrize('url', [
+    '/control/login',
+    '/',
+    '/{orga}/{event}/',
+])
+@pytest.mark.django_db
+def test_csp_header_unauthenticated(client, url, event):
+    # Do not reintroduce any CSP nonces into most presale responses, as discussed in PR #6387
+    with scope(organizer=event.organizer):
+        url = url.format(
+            event=event.slug, orga=event.organizer.slug,
+        )
+        event.live = True
+        event.save()
+    response = client.get(url)
+    assert response.status_code == 200
+    assert 'script-src' in response['Content-Security-Policy']
+    assert 'nonce-' not in response['Content-Security-Policy']

src/tests/presale/test_event.py

@@ -1132,7 +1132,7 @@ class WaitingListTest(EventTestMixin, SoupTest):
     def test_auto_disable(self):
         self.event.settings.set('waiting_list_enabled', True)
         self.event.settings.waiting_list_auto_disable = RelativeDateWrapper(
-            RelativeDate(days=900, time=datetime.time(9, 0, 0), base_date_name='date_from', minutes=None, is_after=False)
+            RelativeDate(days=900, time=datetime.time(9, 0, 0), base_date_name='event__date_from', minutes=None, is_after=False)
         )
         response = self.client.get(
             '/%s/%s/' % (self.orga.slug, self.event.slug)

src/tests/presale/test_order_change.py

@@ -1527,7 +1527,7 @@ class OrderChangeAddonsTest(BaseOrdersTest):
         self.order.save()
         self._subevent_setup()
         self.event.settings.set('payment_term_last', RelativeDateWrapper(
-            RelativeDate(days=2, time=None, base_date_name='date_from', minutes=None)
+            RelativeDate(days=2, time=None, base_date_name='event__date_from', minutes=None)
         ))
 
         response = self.client.get(

src/tests/presale/test_orders.py

@@ -1076,7 +1076,7 @@ class OrdersTest(BaseOrdersTest):
         self.event.date_from = now() + datetime.timedelta(days=3)
         self.event.save()
         self.event.settings.set('ticket_download_date', RelativeDateWrapper(RelativeDate(
-            base_date_name='date_from', days=2, time=None, minutes=None
+            base_date_name='event__date_from', days=2, time=None, minutes=None
         )))
         response = self.client.post(
             '/%s/%s/order/%s/%s/download/%d/testdummy' % (self.orga.slug, self.event.slug, self.order.code,