Disable pickling

Author: Viicos

src/test_typing_extensions.py

@@ -9124,6 +9124,14 @@ def test_sentinel_not_callable(self):
         ):
             sentinel()
 
+    def test_sentinel_not_picklable(self):
+        sentinel = Sentinel('sentinel')
+        with self.assertRaisesRegex(
+            TypeError,
+            "Cannot pickle 'Sentinel' object"
+        ):
+            pickle.dumps(sentinel)
+
 
 if __name__ == '__main__':
     main()

src/typing_extensions.py

@@ -4258,6 +4258,9 @@ def __or__(self, other):
     def __ror__(self, other):
         return Union[other, self]
 
+    def __getstate__(self):
+        raise TypeError(f"Cannot pickle {type(self).__name__!r} object")
+
 
 # Aliases for items that are in typing in all supported versions.
 # Explicitly assign these (rather than using `from typing import *` at the top),