New Signal: order_expiry_changed (#4867)

Co-authored-by: Raphael Michel <michel@rami.io>

doc/development/api/general.rst

@@ -23,7 +23,7 @@ There are multiple signals that will be sent out in the ordering cycle:
 
 .. automodule:: pretix.base.signals
    :no-index:
-   :members: validate_cart, validate_cart_addons, validate_order, order_valid_if_pending, order_fee_calculation, order_paid, order_placed, order_canceled, order_reactivated, order_expired, order_modified, order_changed, order_approved, order_denied, order_fee_type_name, allow_ticket_download, order_split, order_gracefully_delete, invoice_line_text
+   :members: validate_cart, validate_cart_addons, validate_order, order_valid_if_pending, order_fee_calculation, order_paid, order_placed, order_canceled, order_reactivated, order_expired, order_expiry_changed, order_modified, order_changed, order_approved, order_denied, order_fee_type_name, allow_ticket_download, order_split, order_gracefully_delete, invoice_line_text
 
 Check-ins
 """""""""

src/pretix/base/services/orders.py

@@ -98,8 +98,9 @@ from pretix.base.services.quotas import QuotaAvailability
 from pretix.base.services.tasks import ProfiledEventTask, ProfiledTask
 from pretix.base.signals import (
     order_approved, order_canceled, order_changed, order_denied, order_expired,
-    order_fee_calculation, order_paid, order_placed, order_reactivated,
+    order_expiry_changed, order_fee_calculation, order_paid, order_placed,
-    order_split, order_valid_if_pending, periodic_task, validate_order,
+    order_reactivated, order_split, order_valid_if_pending, periodic_task,
+    validate_order,
 )
 from pretix.base.timemachine import time_machine_now, time_machine_now_assigned
 from pretix.celery_app import app
@@ -302,6 +303,7 @@ def extend_order(order: Order, new_date: datetime, force: bool=False, valid_if_p
                     'state_change': was_expired
                 }
             )
+            order_expiry_changed.send(sender=order.event, order=order)
 
         if was_expired:
             num_invoices = order.invoices.filter(is_cancellation=False).count()

src/pretix/base/signals.py

@@ -563,6 +563,16 @@ as the first argument.
 As with all event-plugin signals, the ``sender`` keyword argument will contain the event.
 """
 
+order_expiry_changed = EventPluginSignal()
+"""
+Arguments: ``order``
+
+This signal is sent out every time an order expiry date is changed as an explicit operation (i.e. not if
+this is the result of an approval or order change). The order object is given as the first argument.
+
+As with all event-plugin signals, the ``sender`` keyword argument will contain the event.
+"""
+
 order_modified = EventPluginSignal()
 """
 Arguments: ``order``