[3.10] gh-94245: Fix pickling and copying of typing.Tuple[()] (GH-94260)

Author: serhiy-storchaka

Lib/typing.py

@@ -1099,7 +1099,8 @@ def __reduce__(self):
         else:
             origin = self.__origin__
         args = tuple(self.__args__)
-        if len(args) == 1 and not isinstance(args[0], tuple):
+        if len(args) == 1 and (not isinstance(args[0], tuple) or
+                               origin is Tuple and not args[0]):
             args, = args
         return operator.getitem, (origin, args)
 

Misc/NEWS.d/next/Library/2022-06-25-13-33-18.gh-issue-94245.-zQY1a.rst

@@ -0,0 +1 @@
+Fix pickling and copying of ``typing.Tuple[()]``.