Group identical add-ons in cart (#2500)

Co-authored-by: Richard Schreiber <schreiber@rami.io>

src/pretix/base/email.py

@@ -177,7 +177,7 @@ class TemplateBasedMailRenderer(BaseHTMLMailRenderer):
                     op.variation,
                     op.subevent,
                     op.attendee_name,
-                    (op.pk if op.addon_to_id else None),
+                    op.addon_to_id,
                     (op.pk if op.has_addons else None)
                 )
             )]

src/pretix/base/models/orders.py

@@ -1330,6 +1330,10 @@ class AbstractPosition(models.Model):
         else:
             return {}
 
+    @property
+    def item_and_variation(self):
+        return self.item, self.variation
+
     @meta_info_data.setter
     def meta_info_data(self, d):
         self.meta_info = json.dumps(d)

src/pretix/base/templates/pretixbase/email/order_details.html

@@ -90,13 +90,16 @@
                         {% for groupkey, positions in cart %}
                             <tr>
                                 <td>
-                                    {% if not groupkey.4 %} {# is addon #}
+                                    {% if not groupkey.4 %} {# is not addon #}
                                         {{ positions|length }}x
                                     {% endif %}
                                 </td>
                                 <td>
                                     {% if groupkey.4 %} {# is addon #}
                                         +
+                                        {% if positions|length > 1 %}
+                                            {{ positions|length }}x
+                                        {% endif %}
                                     {% endif %}
                                     {{ groupkey.0.name }}{% if groupkey.1 %} – {{ groupkey.1.value }}{% endif %}
                                     {% if groupkey.2 %} {# subevent #}