Catch msgspec DecodeError by name when reading corrupt store files

Author: T4rk1n

dash/_shared_storage/_codec.py

@@ -11,6 +11,10 @@
 
 import msgspec
 
+# msgspec raises this on malformed input. It subclasses ``ValueError`` in
+# current msgspec but not in every version, so callers should catch it by name.
+DecodeError = msgspec.DecodeError
+
 _encoder = msgspec.msgpack.Encoder()
 _decoder = msgspec.msgpack.Decoder()
 

dash/_shared_storage/_persistence.py

@@ -107,8 +107,9 @@ def _read(path: str) -> Optional[Any]:
         try:
             with open(path, "rb") as f:
                 return _codec.decode(f.read())
-        except (OSError, ValueError):
-            # OSError -> missing/unreadable; ValueError -> msgspec DecodeError.
+        except (OSError, ValueError, _codec.DecodeError):
+            # OSError -> missing/unreadable; DecodeError -> corrupt msgpack
+            # (caught by name since it does not subclass ValueError everywhere).
             return None
 
     def _write_chunk(self, chunk_num: int) -> None: