Use deserialized data structures for mapping configuration (#5351)

src/pretix/base/datasync/datasync.py

@@ -25,7 +25,7 @@ import logging
 from collections import namedtuple
 from datetime import timedelta
 from functools import cached_property
-from typing import Optional, Protocol
+from typing import List, Optional, Protocol
 
 import sentry_sdk
 from django.db import DatabaseError, transaction
@@ -176,7 +176,7 @@ class OutboundSyncProvider:
                 - `pretix_id_field`: Which pretix data field should be used to identify the mapped object. Any ``DataFieldInfo.key``
                   returned by ``sourcefields.get_data_fields()`` for the combination of ``Event`` and ``pretix_model``.
                 - `external_id_field`: Destination identifier field in the target system.
-                - `property_mappings`: Mapping configuration as generated by ``PropertyMappingFormSet.to_property_mappings_json()``.
+                - `property_mappings`: Mapping configuration as generated by ``PropertyMappingFormSet.to_property_mappings_list()``.
         """
         raise NotImplementedError
 
@@ -270,8 +270,7 @@ class OutboundSyncProvider:
             val = ",".join(val)
         return val
 
-    def get_properties(self, inputs: dict, property_mappings: str):
-        property_mappings = json.loads(property_mappings)
+    def get_properties(self, inputs: dict, property_mappings: List[dict]):
         return [
             (m["external_field"], self.get_field_value(inputs, m), m["overwrite"])
             for m in property_mappings