Only depend on typing_extensions for Python < 3.10

pyproject.toml

@@ -43,7 +43,7 @@ dependencies = [
   "packaging>=20",
   "setuptools",
   'tomli>=1; python_version < "3.11"',
-  "typing-extensions",
+  'typing-extensions; python_version < "3.10"',
 ]
 [project.optional-dependencies]
 docs = [
@@ -61,6 +61,7 @@ test = [
   "build",
   "pytest",
   "rich",
+  'typing-extensions; python_version < "3.11"',
   "wheel",
 ]
 toml = [

src/setuptools_scm/_file_finders/__init__.py

@@ -12,7 +12,12 @@
 from .pathtools import norm_real
 
 if TYPE_CHECKING:
-    from typing_extensions import TypeGuard
+    import sys
+
+    if sys.version_info >= (3, 10):
+        from typing import TypeGuard
+    else:
+        from typing_extensions import TypeGuard
 
 
 log = _log.log.getChild("file_finder")

src/setuptools_scm/_integration/toml.py

@@ -16,7 +16,10 @@
     from tomli import loads as load_toml
 
 if TYPE_CHECKING:
-    from typing_extensions import TypeAlias
+    if sys.version_info >= (3, 10):
+        from typing import TypeAlias
+    else:
+        from typing_extensions import TypeAlias
 
 from .. import _log
 

src/setuptools_scm/_types.py

@@ -10,7 +10,12 @@
 from typing import Union
 
 if TYPE_CHECKING:
-    from typing_extensions import TypeAlias
+    import sys
+
+    if sys.version_info >= (3, 10):
+        from typing import TypeAlias
+    else:
+        from typing_extensions import TypeAlias
 
     from . import version
 

src/setuptools_scm/version.py

@@ -18,8 +18,14 @@
 from . import _modify_version
 
 if TYPE_CHECKING:
-    from typing_extensions import Concatenate
-    from typing_extensions import ParamSpec
+    import sys
+
+    if sys.version_info >= (3, 10):
+        from typing import Concatenate
+        from typing import ParamSpec
+    else:
+        from typing_extensions import Concatenate
+        from typing_extensions import ParamSpec
 
     _P = ParamSpec("_P")
 

testing/conftest.py

@@ -2,6 +2,7 @@
 
 import contextlib
 import os
+import sys
 
 from pathlib import Path
 from types import TracebackType
@@ -11,7 +12,11 @@
 import pytest
 
 from setuptools_scm._run_cmd import run
-from typing_extensions import Self
+
+if sys.version_info >= (3, 11):
+    from typing import Self
+else:
+    from typing_extensions import Self
 
 from .wd_wrapper import WorkDir