Move non_null_str_or_none to s.utils.stringutils

2 files changed, 6 insertions, 4 deletions

diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py
index 42d484dc98..0df8ff5395 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -52,6 +52,7 @@ from synapse.storage.util.sequence import SequenceGenerator
 from synapse.types import JsonDict, StateMap, get_domain_from_id
 from synapse.util import json_encoder
 from synapse.util.iterutils import batch_iter, sorted_topologically
+from synapse.util.stringutils import non_null_str_or_none
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
@@ -1728,9 +1729,6 @@ class PersistEventsStore:
                 not affect the current local state.
         """
 
-        def non_null_str_or_none(val: Any) -> Optional[str]:
-            return val if isinstance(val, str) and "\u0000" not in val else None
-
         self.db_pool.simple_insert_many_txn(
             txn,
             table="room_memberships",
diff --git a/synapse/util/stringutils.py b/synapse/util/stringutils.py
index b26546aecd..11246d95e9 100644
--- a/synapse/util/stringutils.py
+++ b/synapse/util/stringutils.py
@@ -16,7 +16,7 @@ import itertools
 import re
 import secrets
 import string
-from typing import Iterable, Optional, Tuple
+from typing import Any, Iterable, Optional, Tuple
 
 from netaddr import valid_ipv6
 
@@ -247,3 +247,7 @@ def base62_encode(num: int, minwidth: int = 1) -> str:
     # pad to minimum width
     pad = "0" * (minwidth - len(res))
     return pad + res
+
+
+def non_null_str_or_none(val: Any) -> Optional[str]:
+    return val if isinstance(val, str) and "\u0000" not in val else None