Allow tax rules to trigger approval requirement (#2409)

src/pretix/base/models/orders.py

@@ -1442,11 +1442,13 @@ class AbstractPosition(models.Model):
         lines = [r.strip() for r in lines if r]
         return '\n'.join(lines).strip()
 
-    def requires_approval(self):
+    def requires_approval(self, invoice_address=None):
         if self.item.require_approval:
             return True
         if self.variation and self.variation.require_approval:
             return True
+        if self.item.tax_rule and self.item.tax_rule._require_approval(invoice_address):
+            return True
         return False
 
 

src/pretix/base/models/tax.py

@@ -211,7 +211,7 @@ class TaxRule(LoggedModel):
             rule = self.get_matching_rule(invoice_address)
             if rule.get('action', 'vat') == 'block':
                 raise self.SaleNotAllowed()
-            if rule.get('action', 'vat') == 'vat' and rule.get('rate') is not None:
+            if rule.get('action', 'vat') in ('vat', 'require_approval') and rule.get('rate') is not None:
                 return Decimal(rule.get('rate'))
         return Decimal(self.rate)
 
@@ -337,12 +337,19 @@ class TaxRule(LoggedModel):
 
         return False
 
+    def _require_approval(self, invoice_address):
+        if self._custom_rules:
+            rule = self.get_matching_rule(invoice_address)
+            if rule.get('action', 'vat') == 'require_approval':
+                return True
+        return False
+
     def _tax_applicable(self, invoice_address):
         if self._custom_rules:
             rule = self.get_matching_rule(invoice_address)
             if rule.get('action', 'vat') == 'block':
                 raise self.SaleNotAllowed()
-            return rule.get('action', 'vat') == 'vat'
+            return rule.get('action', 'vat') in ('vat', 'require_approval')
 
         if not self.eu_reverse_charge:
             # No reverse charge rules? Always apply VAT!