Fix incorrect setting if Invoice.full_invoice_no

src/pretix/base/models/invoices.py

@@ -264,6 +264,7 @@ class Invoice(models.Model):
                     self.invoice_no = self._get_invoice_number_from_order()
                 try:
                     with transaction.atomic():
+                        self.full_invoice_no = self.prefix + self.invoice_no
                         return super().save(*args, **kwargs)
                 except DatabaseError:
                     # Suppress duplicate key errors and try again

src/tests/base/test_invoices.py

@@ -522,7 +522,9 @@ def test_invoice_number_prefixes(env):
     event2.settings.set('invoice_numbers_counter_length', 4)
     i = generate_invoice(order2)
     assert i.number == 'inv_0001'
-    assert generate_cancellation(i).number == 'crd_0001'
+    ci = generate_cancellation(i)
+    assert ci.number == 'crd_0001'
+    assert ci.full_invoice_no == 'crd_0001'
 
     event2.settings.set('invoice_numbers_consecutive', False)
     i = generate_invoice(order2)