Use typing-extensions only on Python < 3.8 (#44)

Author: mgorny

asyncstdlib/_lrucache.py

@@ -17,8 +17,12 @@
 )
 from functools import update_wrapper
 from collections import OrderedDict
+import sys
 
-from typing_extensions import Protocol, TypedDict
+if sys.version_info[:2] >= (3, 8):
+    from typing import Protocol, TypedDict
+else:
+    from typing_extensions import Protocol, TypedDict
 
 from ._utility import public_module
 

asyncstdlib/asynctools.py

@@ -10,7 +10,12 @@
     Any,
     overload,
 )
-from typing_extensions import AsyncContextManager
+import sys
+
+if sys.version_info[:2] >= (3, 8):
+    from typing import AsyncContextManager
+else:
+    from typing_extensions import AsyncContextManager
 
 from ._core import AnyIterable, aiter
 from .contextlib import nullcontext

asyncstdlib/contextlib.py

@@ -8,12 +8,16 @@
     Any,
     Awaitable,
 )
-from typing_extensions import Protocol, AsyncContextManager, ContextManager
 from functools import wraps
 from collections import deque
 from functools import partial
 import sys
 
+if sys.version_info[:2] >= (3, 8):
+    from typing import Protocol, AsyncContextManager, ContextManager
+else:
+    from typing_extensions import Protocol, AsyncContextManager, ContextManager
+
 from ._core import awaitify
 from ._utility import public_module, slot_get as _slot_get
 

pyproject.toml

@@ -16,7 +16,7 @@ classifiers = [
     "License :: OSI Approved :: MIT License",
     "Programming Language :: Python :: 3 :: Only",
 ]
-requires = ["typing_extensions"]
+requires = ["typing_extensions; python_version<'3.8'"]
 
 [tool.flit.metadata.requires-extra]
 test = [