Fix order split with add-ons involved (#2513)

src/pretix/base/services/orders.py

@@ -1527,6 +1527,8 @@ class OrderChangeManager:
             self._invoice_dirty = True
 
         self._operations.append(self.SplitOperation(position))
+        for a in position.addons.all():
+            self._operations.append(self.SplitOperation(a))
 
     def set_addons(self, addons):
         if self._operations:

src/pretix/control/forms/orders.py

@@ -482,6 +482,9 @@ class OrderPositionChangeForm(forms.Form):
         self.fields['tax_rule'].queryset = instance.event.tax_rules.all()
         self.fields['tax_rule'].label_from_instance = self.taxrule_label_from_instance
 
+        if instance.addon_to_id:
+            del self.fields['operation_split']
+
         if not instance.seat and not (
                 instance.item.seat_category_mappings.filter(subevent=instance.subevent).exists()
         ):

src/pretix/control/templates/pretixcontrol/order/change.html

@@ -202,10 +202,12 @@
                         </div>
 
                         {% bootstrap_field position.form.operation_cancel layout='inline' %}
-                        {% bootstrap_field position.form.operation_split layout='inline' %}
+                        {% if position.form.operation_split %}
+                            {% bootstrap_field position.form.operation_split layout='inline' %}
+                        {% endif %}
                         {% if position.addons.exists %}
                             <em class="text-danger">
-                                {% trans "Removing this position will also remove all add-ons to this position." %}
+                                {% trans "Removing or splitting this position will also remove or split all add-ons to this position." %}
                             </em>
                         {% endif %}
                     </div>

src/pretix/control/views/orders.py

@@ -1760,7 +1760,7 @@ class OrderChange(OrderView):
                 if p.form.cleaned_data['tax_rule'] and p.form.cleaned_data['tax_rule'] != p.tax_rule:
                     ocm.change_tax_rule(p, p.form.cleaned_data['tax_rule'])
 
-                if p.form.cleaned_data['operation_split']:
+                if p.form.cleaned_data.get('operation_split'):
                     ocm.split(p)
 
                 if p.form.cleaned_data['operation_secret']:

src/tests/base/test_orders.py

@@ -1782,6 +1782,37 @@ class OrderChangeManagerTests(TestCase):
         assert not self.order.invoices.exists()
         assert not o2.invoices.exists()
 
+    @classscope(attr='o')
+    def test_split_include_addons(self):
+        self.shirt.category = self.event.categories.create(name='Add-ons', is_addon=True)
+        self.ticket.addons.create(addon_category=self.shirt.category)
+        self.ocm.add_position(self.shirt, None, Decimal('13.00'), self.op2)
+        self.ocm.commit()
+        self.order.refresh_from_db()
+        self.ocm = OrderChangeManager(self.order, None)
+        a = self.order.positions.get(addon_to=self.op2)
+
+        old_secret = self.op2.secret
+        self.ocm.split(self.op2)
+        self.ocm.commit()
+        self.order.refresh_from_db()
+        self.op2.refresh_from_db()
+        a.refresh_from_db()
+        assert self.order.total == Decimal('23.00')
+        assert self.order.positions.count() == 1
+        assert self.op2.order != self.order
+        o2 = self.op2.order
+        assert o2.total == Decimal('36.00')
+        assert o2.positions.count() == 2
+        assert o2.code != self.order.code
+        assert o2.secret != self.order.secret
+        assert o2.datetime > self.order.datetime
+        assert a.addon_to == self.op2
+        assert a.order == o2
+        assert self.op2.secret != old_secret
+        assert not self.order.invoices.exists()
+        assert not o2.invoices.exists()
+
     @classscope(attr='o')
     def test_split_require_approval(self):
         self.op2.item.require_approval = True