Reject non-string atomic text writes (#1819)

core/atomic_io.py

@@ -34,6 +34,8 @@ def atomic_write_json(path: str, data: Any, *, indent: Optional[int] = None) ->
 
 
 def atomic_write_text(path: str, text: str) -> None:
+    if not isinstance(text, str):
+        raise TypeError("atomic_write_text expects a string")
     os.makedirs(os.path.dirname(path) or ".", exist_ok=True)
     tmp = f"{path}.tmp.{os.getpid()}"
     with open(tmp, "w", encoding="utf-8") as f: