sources/ldap: use merger that only appends unique items to list

closes #2211

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

authentik/lib/merge.py

@@ -0,0 +1,6 @@
+"""merge utils"""
+from deepmerge import Merger
+
+MERGE_LIST_UNIQUE = Merger(
+    [(list, ["append_unique"]), (dict, ["merge"]), (set, ["union"])], ["override"], ["override"]
+)

authentik/sources/ldap/sync/base.py

@@ -1,13 +1,13 @@
 """Sync LDAP Users and groups into authentik"""
 from typing import Any
 
-from deepmerge import always_merger
 from django.db.models.base import Model
 from django.db.models.query import QuerySet
 from structlog.stdlib import BoundLogger, get_logger
 
 from authentik.core.exceptions import PropertyMappingExpressionException
 from authentik.events.models import Event, EventAction
+from authentik.lib.merge import MERGE_LIST_UNIQUE
 from authentik.sources.ldap.auth import LDAP_DISTINGUISHED_NAME
 from authentik.sources.ldap.models import LDAPPropertyMapping, LDAPSource
 
@@ -123,8 +123,8 @@ class BaseLDAPSynchronizer:
                 continue
             setattr(instance, key, value)
         final_atttributes = {}
-        always_merger.merge(final_atttributes, instance.attributes)
-        always_merger.merge(final_atttributes, data.get("attributes", {}))
+        MERGE_LIST_UNIQUE.merge(final_atttributes, instance.attributes)
+        MERGE_LIST_UNIQUE.merge(final_atttributes, data.get("attributes", {}))
         instance.attributes = final_atttributes
         instance.save()
         return (instance, False)