handle country=None in InvoiceAddress even if it is not allowed

src/pretix/base/models/customers.py

@@ -395,7 +395,7 @@ class AttendeeProfile(models.Model):
             self.company,
             self.street,
             (self.zipcode or '') + ' ' + (self.city or '') + ' ' + (self.state_for_address or ''),
-            self.country.name,
+            self.country.name if self.country else None,
         ]
         for a in self.answers:
             value = a.get('value')

src/pretix/base/models/orders.py

@@ -1697,7 +1697,7 @@ class AbstractPosition(RoundingCorrectionMixin, models.Model):
             self.company,
             self.street,
             (self.zipcode or '') + ' ' + (self.city or '') + ' ' + (self.state_for_address or ''),
-            self.country.name
+            self.country.name if self.country else ''
         ]
         lines = [r.strip() for r in lines if r]
         return '\n'.join(lines).strip()
@@ -3438,7 +3438,7 @@ class InvoiceAddress(models.Model):
             self.name,
             self.street,
             (self.zipcode or '') + ' ' + (self.city or '') + ' ' + (self.state_for_address or ''),
-            self.country.name,
+            self.country.name if self.country else '',
             self.vat_id,
             self.custom_field,
             self.internal_reference,

src/pretix/presale/checkoutflow.py

@@ -1158,7 +1158,7 @@ class QuestionsStep(QuestionsViewMixin, CartMixin, TemplateFlowStep):
                 for a in addresses:
                     data = {
                         "_pk": a.pk,
-                        "_country_for_address": a.country.name,
+                        "_country_for_address": a.country.name if a.country else '',
                         "_state_for_address": a.state_for_address,
                         "_name": a.name,
                         "is_business": "business" if a.is_business else "individual",
@@ -1201,7 +1201,7 @@ class QuestionsStep(QuestionsViewMixin, CartMixin, TemplateFlowStep):
             for p in profiles:
                 data = {
                     "_pk": p.pk,
-                    "_country_for_address": p.country.name,
+                    "_country_for_address": p.country.name if p.country else '',
                     "_state_for_address": p.state_for_address,
                     "_attendee_name": p.attendee_name,
                 }

src/pretix/presale/templates/pretixpresale/event/checkout_confirm.html

@@ -90,7 +90,7 @@
                                 <dt>{% trans "ZIP code and city" %}</dt>
                                 <dd>{{ addr.zipcode }} {{ addr.city }}</dd>
                                 <dt>{% trans "Country" %}</dt>
-                                <dd>{{ addr.country.name }}</dd>
+                                <dd>{{ addr.country.name|default_if_none:"" }}</dd>
                                 {% if addr.state %}
                                     <dt>{% trans "State" context "address" as state_label %}{{ COUNTRY_STATE_LABEL|getitem:addr.country.code|default:state_label }}</dt>
                                     <dd>{{ addr.state_name }}</dd>