feat: add warning about data loss/corruption with JSONStorage access_mode options

msiemens · msiemens · commit 505d782e27e1 · 2023-02-18T22:25:04.000+01:00
Closes: msiemens#506
diff --git a/tinydb/storages.py b/tinydb/storages.py
@@ -6,6 +6,7 @@
 import io
 import json
 import os
+import warnings
 from abc import ABC, abstractmethod
 from typing import Dict, Any, Optional
 
@@ -100,6 +101,12 @@ def __init__(self, path: str, create_dirs=False, encoding=None, access_mode='r+'
         self._mode = access_mode
         self.kwargs = kwargs
 
+        if access_mode not in ('r', 'rb', 'r+', 'rb+'):
+            warnings.warn(
+                'Using an `access_mode` other than \'r\', \'rb\', \'r+\' '
+                'or \'rb+\' can cause data loss or corruption'
+            )
+
         # Create the file if it doesn't exist and creating is allowed by the
         # access mode
         if any([character in self._mode for character in ('+', 'w', 'a')]):  # any of the writing modes
